1 files changed, 0 insertions, 1 deletions
diff --git a/tool/ruby_vm/controllers/application_controller.rb b/tool/ruby_vm/controllers/application_controller.rb
index e03e54e397..f6c0e39600 100644
--- a/tool/ruby_vm/controllers/application_controller.rb
+++ b/tool/ruby_vm/controllers/application_controller.rb
@@ -1,4 +1,3 @@
-#! /your/favourite/path/to/ruby
 # -*- Ruby -*-
 # -*- frozen_string_literal: true; -*-
 # -*- warn_indent: true; -*-
diff --git a/.appveyor.yml b/.appveyor.yml
new file mode 100644
index 0000000000..05ff204541
--- /dev/null
+++ b/.appveyor.yml
@@ -0,0 +1,134 @@
+---
+version: '{build}'
+init:
+  - git config --global user.name git
+  - git config --global user.email svn-admin@ruby-lang.org
+  - git config --global core.autocrlf false
+  - git config --global core.eol lf
+  - git config --global advice.detachedHead 0
+shallow_clone: true
+clone_depth: 10
+platform:
+  - x64
+skip_commits:
+  message: /\[DOC\]/
+  files:
+    - doc/*
+    - '**/*.md'
+    - '**/*.rdoc'
+    - '**/.document'
+    - '**/*.[1-8]'
+    - '**/*.ronn'
+environment:
+  ruby_version: "24-%Platform%"
+  matrix:
+    # Test only the oldest supported version because AppVeyor is unstable, its concurrency
+    # is limited, and compatibility issues that happen only in newer versions are rare.
+    # You may test some other stuff on GitHub Actions instead.
+    - build: vs
+      vs: 120 # Visual Studio 2013
+      ssl: OpenSSL-v111
+      # The worker image name. This is NOT the Visual Studio version we're using here.
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
+      GEMS_FOR_TEST: ""
+  RELINE_TEST_ENCODING: "UTF-8"
+cache:
+  - c:\Tools\vcpkg\installed\
+for:
+-
+  matrix:
+    only:
+      - build: vs
+  install:
+    - ver
+    - chcp
+    - SET BITS=%Platform:x86=32%
+    - SET BITS=%BITS:x=%
+    - SET OPENSSL_DIR=C:\%ssl%-Win%BITS%
+    - cd C:\Tools\vcpkg
+    - git pull -q
+    - .\bootstrap-vcpkg.bat
+    - ps: Start-FileDownload 'https://github.com/microsoft/vcpkg-tool/releases/download/2023-08-09/vcpkg.exe' -FileName 'C:\Tools\vcpkg\vcpkg.exe'
+    - cd %APPVEYOR_BUILD_FOLDER%
+    - vcpkg --triplet %Platform%-windows install --x-use-aria2 libffi libyaml readline zlib
+    - CALL SET vcvars=%%^VS%VS%COMNTOOLS^%%..\..\VC\vcvarsall.bat
+    - SET vcvars
+    - '"%vcvars%" %Platform:x64=amd64%'
+    - SET ruby_path=C:\Ruby%ruby_version:-x86=%
+    - SET PATH=\usr\local\bin;%ruby_path%\bin;%PATH%;C:\msys64\mingw64\bin;C:\msys64\usr\bin
+    - ruby --version
+    - 'cl'
+    - echo> Makefile srcdir=.
+    - echo>> Makefile MSC_VER=0
+    - echo>> Makefile RT=none
+    - echo>> Makefile RT_VER=0
+    - echo>> Makefile BUILTIN_ENCOBJS=nul
+    - type win32\Makefile.sub >> Makefile
+    - nmake %mflags% up VCSUP="echo Update OK"
+    - nmake %mflags% extract-extlibs
+    - del Makefile
+    - mkdir \usr\local\bin
+    - mkdir \usr\local\include
+    - mkdir \usr\local\lib
+    - for %%I in (%OPENSSL_DIR%\*.dll) do mklink /h \usr\local\bin\%%~nxI %%I
+    - for %%I in (c:\Tools\vcpkg\installed\%Platform%-windows\bin\*.dll) do (
+        if not %%~nI == readline mklink \usr\local\bin\%%~nxI %%I
+      )
+    - attrib +r /s /d
+    - mkdir %Platform%-mswin_%vs%
+  build_script:
+    - set HAVE_GIT=no
+    - cd %APPVEYOR_BUILD_FOLDER%
+    - cd %Platform%-mswin_%vs%
+    - >-
+      ..\win32\configure.bat
+      --with-opt-dir="/usr/local;c:/Tools/vcpkg/installed/%Platform%-windows"
+      --with-openssl-dir=%OPENSSL_DIR:\=/%
+    - nmake -l
+    - nmake install-nodoc
+    - \usr\bin\ruby -v -e "p :locale => Encoding.find('locale'), :filesystem => Encoding.find('filesystem')"
+    - if not "%GEMS_FOR_TEST%" == "" \usr\bin\gem install --no-document %GEMS_FOR_TEST%
+    - \usr\bin\ruby -ropenssl -e "puts 'Build    ' + OpenSSL::OPENSSL_VERSION, 'Runtime  ' + OpenSSL::OPENSSL_LIBRARY_VERSION"
+  test_script:
+    - set /a JOBS=%NUMBER_OF_PROCESSORS%
+    - nmake -l "TESTOPTS=-v -q" btest
+    - nmake -l "TESTOPTS=-v -q" test-basic
+    - >-
+      nmake -l "TESTOPTS=--timeout-scale=3.0
+      --excludes=../test/excludes/_appveyor -j%JOBS%
+      --exclude win32ole
+      --exclude test_bignum
+      --exclude test_syntax
+      --exclude test_open-uri
+      --exclude test_bundled_ca
+      " test-all
+    # separately execute tests without -j which may crash worker with -j.
+    - >-
+      nmake -l
+      "TESTOPTS=--timeout-scale=3.0 --excludes=../test/excludes/_appveyor"
+      TESTS="
+      ../test/win32ole
+      ../test/ruby/test_bignum.rb
+      ../test/ruby/test_syntax.rb
+      ../test/open-uri/test_open-uri.rb
+      ../test/rubygems/test_bundled_ca.rb
+      " test-all
+    - nmake -l test-spec MSPECOPT=-fs # not using `-j` because sometimes `mspec -j` silently dies on Windows
+notifications:
+  - provider: Webhook
+    method: POST
+    url:
+      secure: CcFlJNDJ/a6to7u3Z4Fnz6dScEPNx7hTha2GkSRlV+1U6dqmxY/7uBcLXYb9gR3jfQk6w+2o/HrjNAyXMNGU/JOka3s2WRI4VKitzM+lQ08owvJIh0R7LxrGH0J2e81U # ruby-lang slack: ruby/simpler-alerts-bot
+    body: >-
+      {{^isPullRequest}}
+        {
+          "ci": "AppVeyor CI",
+          "env": "Visual Studio 2013",
+          "url": "{{buildUrl}}",
+          "commit": "{{commitId}}",
+          "branch": "{{branch}}"
+        }
+      {{/isPullRequest}}
+    on_build_success: false
+    on_build_failure: true
+    on_build_status_changed: false
diff --git a/.dir-locals.el b/.dir-locals.el
new file mode 100644
index 0000000000..8f4b96445c
--- /dev/null
+++ b/.dir-locals.el
@@ -0,0 +1,39 @@
+;; Copyright (c) 2018 Urabe, Shyouhei.  All rights reserved.
+;;
+;; This file is a part of  the programming language Ruby.  Permission is hereby
+;; granted, to either  redistribute and/or modify this file,  provided that the
+;; conditions mentioned  in the  file COPYING  are met.   Consult the  file for
+;; details.
+
+((nil .
+     ((indent-tabs-mode . nil)
+      (require-final-newline . t)
+      (tab-width . 8)
+      (show-trailing-whitespace . t)
+      (whitespace-line-column . 80))) ;; See also [Misc #12277]
+
+ ;; (bat-mode . ((buffer-file-coding-system . utf-8-dos)))
+
+ (ruby-mode . ((ruby-indent-level . 2)))
+
+ (rdoc-mode . ((fill-column . 74)))
+
+ (yaml-mode . ((yaml-indent-offset . 2)))
+
+ (makefile-mode . ((indent-tabs-mode . t)))
+
+ (c-mode . ((c-file-style . "ruby")))
+
+ (c++-mode . ((c-file-style . "ruby")))
+
+ (change-log-mode .
+     ((buffer-file-coding-system . us-ascii)
+      (indent-tabs-mode . t)
+      (change-log-indent-text . 2)
+      (add-log-time-format . (lambda (&optional x y)
+        (let* ((time (or x (current-time)))
+	       (system-time-locale "C")
+	       (diff (+ (cadr time) 32400))
+	       (lo (% diff 65536))
+	       (hi (+ (car time) (/ diff 65536))))
+        (format-time-string "%a %b %e %H:%M:%S %Y" (list hi lo) t)))))))
diff --git a/.document b/.document
index 9a5067bc52..3a6b0c238c 100644
--- a/.document
+++ b/.document
@@ -5,9 +5,31 @@
 
 # Process all the C source files
 *.c
+*.y
 
 # prelude
 prelude.rb
+rbconfig.rb
+
+array.rb
+ast.rb
+dir.rb
+gc.rb
+io.rb
+kernel.rb
+marshal.rb
+mjit.rb
+numeric.rb
+nilclass.rb
+pack.rb
+ractor.rb
+string.rb
+symbol.rb
+timev.rb
+thread_sync.rb
+trace_point.rb
+warning.rb
+yjit.rb
 
 # the lib/ directory (which has its own .document file)
 lib
@@ -16,13 +38,17 @@ lib
 ext
 
 # rdoc files
-ChangeLog
+NEWS.md
 
-NEWS
+README.md
+README.ja.md
 
-README
-README.EXT
-README.EXT.ja
-README.ja
+COPYING
+COPYING.ja
+
+LEGAL
+
+# win32/README.win32 linked from README.md
+win32
 
 doc
diff --git a/.editorconfig b/.editorconfig
index 67abf4b978..4633a7acae 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -2,15 +2,29 @@ root = true
 
 [*]
 end_of_line = lf
+indent_size = 4
+indent_style = space
 insert_final_newline = true
-trim_trailing_whitespace = true
 tab_width = 8
-indent_style = tab
-indent_size = 4
+trim_trailing_whitespace = true
 
-[**.bat]
+[*.bat]
 end_of_line = crlf
 
-[**.rb]
-indent_style = space
+[*.gemspec]
+indent_size = 2
+
+[*.rb]
+indent_size = 2
+
+[*.yml]
+indent_size = 2
+
+[{*[Mm]akefile*,*.mak,*.mk,depend}]
+indent_style = tab
+
+[enc/*]
+indent_size = 2
+
+[reg*.[ch]]
 indent_size = 2
diff --git a/.gdbinit b/.gdbinit
index 17be7d8779..34d044caf6 100644
--- a/.gdbinit
+++ b/.gdbinit
@@ -1,3 +1,5 @@
+set startup-with-shell off
+
 define hook-run
   set $color_type = 0
   set $color_highlite = 0
@@ -50,7 +52,7 @@ define rp
     end
   else
   set $flags = ((struct RBasic*)($arg0))->flags
-  if ($flags & RUBY_FL_PROMOTED)
+  if ($flags & RUBY_FL_PROMOTED) == RUBY_FL_PROMOTED
     printf "[PROMOTED] "
   end
   if ($flags & RUBY_T_MASK) == RUBY_T_NONE
@@ -63,7 +65,15 @@ define rp
   else
   if ($flags & RUBY_T_MASK) == RUBY_T_OBJECT
     printf "%sT_OBJECT%s: ", $color_type, $color_end
-    print (struct RObject *)($arg0)
+    print ((struct RObject *)($arg0))->basic
+    if ($flags & ROBJECT_EMBED)
+      print/x *((VALUE*)((struct RObject*)($arg0))->as.ary) @ (ROBJECT_EMBED_LEN_MAX+0)
+    else
+      print (((struct RObject *)($arg0))->as.heap)
+      if (((struct RObject*)($arg0))->as.heap.numiv) > 0
+        print/x *(((struct RObject*)($arg0))->as.heap.ivptr) @ (((struct RObject*)($arg0))->as.heap.numiv)
+      end
+    end
   else
   if ($flags & RUBY_T_MASK) == RUBY_T_CLASS
     printf "%sT_CLASS%s%s: ", $color_type, ($flags & RUBY_FL_SINGLETON) ? "*" : "", $color_end
@@ -89,14 +99,15 @@ define rp
     set $regsrc = ((struct RRegexp*)($arg0))->src
     set $rsflags = ((struct RBasic*)$regsrc)->flags
     printf "%sT_REGEXP%s: ", $color_type, $color_end
+    set $len = ($rsflags & RUBY_FL_USER1) ? \
+            ((struct RString*)$regsrc)->as.heap.len : \
+            (($rsflags & (RUBY_FL_USER2|RUBY_FL_USER3|RUBY_FL_USER4|RUBY_FL_USER5|RUBY_FL_USER6)) >> RUBY_FL_USHIFT+2)
     set print address off
-    output (char *)(($rsflags & RUBY_FL_USER1) ? \
+    output *(char *)(($rsflags & RUBY_FL_USER1) ? \
 	    ((struct RString*)$regsrc)->as.heap.ptr : \
-	    ((struct RString*)$regsrc)->as.ary)
+	    ((struct RString*)$regsrc)->as.ary) @ $len
     set print address on
-    printf " len:%ld ", ($rsflags & RUBY_FL_USER1) ? \
-            ((struct RString*)$regsrc)->as.heap.len : \
-            (($rsflags & (RUBY_FL_USER2|RUBY_FL_USER3|RUBY_FL_USER4|RUBY_FL_USER5|RUBY_FL_USER6)) >> RUBY_FL_USHIFT+2)
+    printf " len:%ld ", $len
     if $flags & RUBY_FL_USER6
       printf "(none) "
     end
@@ -117,7 +128,7 @@ define rp
       if ($len == 0)
 	printf "{(empty)} "
       else
-	output/x *((VALUE*)((struct RArray*)($arg0))->as.ary) @ $len
+	print/x *((VALUE*)((struct RArray*)($arg0))->as.ary) @ $len
 	printf " "
       end
     else
@@ -125,7 +136,7 @@ define rp
       printf "%sT_ARRAY%s: len=%ld ", $color_type, $color_end, $len
       if ($flags & RUBY_FL_USER2)
 	printf "(shared) shared="
-	output/x ((struct RArray*)($arg0))->as.heap.aux.shared
+	output/x ((struct RArray*)($arg0))->as.heap.aux.shared_root
 	printf " "
       else
 	printf "(ownership) capa=%ld ", ((struct RArray*)($arg0))->as.heap.aux.capa
@@ -133,7 +144,7 @@ define rp
       if ($len == 0)
 	printf "{(empty)} "
       else
-	output/x *((VALUE*)((struct RArray*)($arg0))->as.heap.ptr) @ $len
+	print/x *((VALUE*)((struct RArray*)($arg0))->as.heap.ptr) @ $len
 	printf " "
       end
     end
@@ -145,34 +156,27 @@ define rp
   else
   if ($flags & RUBY_T_MASK) == RUBY_T_HASH
     printf "%sT_HASH%s: ", $color_type, $color_end,
-    if ((struct RHash *)($arg0))->ntbl
-      printf "len=%ld ", ((struct RHash *)($arg0))->ntbl->num_entries
+    if (((struct RHash *)($arg0))->basic.flags & RHASH_ST_TABLE_FLAG)
+      printf "st len=%ld ", ((struct RHash *)($arg0))->as.st->num_entries
+    else
+      printf "li len=%ld bound=%ld ", \
+        ((((struct RHash *)($arg0))->basic.flags & RHASH_AR_TABLE_SIZE_MASK) >> RHASH_AR_TABLE_SIZE_SHIFT), \
+        ((((struct RHash *)($arg0))->basic.flags & RHASH_AR_TABLE_BOUND_MASK) >> RHASH_AR_TABLE_BOUND_SHIFT)
     end
     print (struct RHash *)($arg0)
   else
   if ($flags & RUBY_T_MASK) == RUBY_T_STRUCT
-    printf "%sT_STRUCT%s: len=%ld ", $color_type, $color_end, \
-      (($flags & (RUBY_FL_USER1|RUBY_FL_USER2)) ? \
+    set $len = (($flags & (RUBY_FL_USER1|RUBY_FL_USER2)) ? \
        ($flags & (RUBY_FL_USER1|RUBY_FL_USER2)) >> (RUBY_FL_USHIFT+1) : \
        ((struct RStruct *)($arg0))->as.heap.len)
+    printf "%sT_STRUCT%s: len=%ld ", $color_type, $color_end, $len
     print (struct RStruct *)($arg0)
-    x/xw (($flags & (RUBY_FL_USER1|RUBY_FL_USER2)) ? \
-          ((struct RStruct *)($arg0))->as.ary : \
-          ((struct RStruct *)($arg0))->as.heap.ptr)
+    output/x *(($flags & (RUBY_FL_USER1|RUBY_FL_USER2)) ? \
+              ((struct RStruct *)($arg0))->as.ary : \
+              ((struct RStruct *)($arg0))->as.heap.ptr) @ $len
   else
   if ($flags & RUBY_T_MASK) == RUBY_T_BIGNUM
-    printf "%sT_BIGNUM%s: sign=%d len=%ld ", $color_type, $color_end, \
-      (($flags & RUBY_FL_USER1) != 0), \
-      (($flags & RUBY_FL_USER2) ? \
-       ($flags & (RUBY_FL_USER5|RUBY_FL_USER4|RUBY_FL_USER3)) >> (RUBY_FL_USHIFT+3) : \
-       ((struct RBignum*)($arg0))->as.heap.len)
-    if $flags & RUBY_FL_USER2
-      printf "(embed) "
-    end
-    print (struct RBignum *)($arg0)
-    x/xw (($flags & RUBY_FL_USER2) ? \
-          ((struct RBignum*)($arg0))->as.ary : \
-          ((struct RBignum*)($arg0))->as.heap.digits)
+    rp_bignum $arg0
   else
   if ($flags & RUBY_T_MASK) == RUBY_T_RATIONAL
     printf "%sT_RATIONAL%s: ", $color_type, $color_end
@@ -211,12 +215,46 @@ define rp
   else
   if ($flags & RUBY_T_MASK) == RUBY_T_SYMBOL
     printf "%sT_SYMBOL%s: ", $color_type, $color_end
-    print (struct RBasic *)($arg0)
+    print (struct RSymbol *)($arg0)
+    set $id_type = ((struct RSymbol *)($arg0))->id & RUBY_ID_SCOPE_MASK
+    if $id_type == RUBY_ID_LOCAL
+      printf "l"
+    else
+    if $id_type == RUBY_ID_INSTANCE
+      printf "i"
+    else
+    if $id_type == RUBY_ID_GLOBAL
+      printf "G"
+    else
+    if $id_type == RUBY_ID_ATTRSET
+      printf "a"
+    else
+    if $id_type == RUBY_ID_CONST
+      printf "C"
+    else
+    if $id_type == RUBY_ID_CLASS
+      printf "c"
+    else
+      printf "j"
+    end
+    end
+    end
+    end
+    end
+    end
+    set $id_fstr = ((struct RSymbol *)($arg0))->fstr
+    rp_string $id_fstr
   else
   if ($flags & RUBY_T_MASK) == RUBY_T_UNDEF
     printf "%sT_UNDEF%s: ", $color_type, $color_end
     print (struct RBasic *)($arg0)
   else
+  if ($flags & RUBY_T_MASK) == RUBY_T_IMEMO
+    printf "%sT_IMEMO%s(", $color_type, $color_end
+    output (enum imemo_type)(($flags>>RUBY_FL_USHIFT)&RUBY_IMEMO_MASK)
+    printf "): "
+    rp_imemo $arg0
+  else
   if ($flags & RUBY_T_MASK) == RUBY_T_NODE
     printf "%sT_NODE%s(", $color_type, $color_end
     output (enum node_type)(($flags&RUBY_NODE_TYPEMASK)>>RUBY_NODE_TYPESHIFT)
@@ -227,6 +265,10 @@ define rp
     printf "%sT_ZOMBIE%s: ", $color_type, $color_end
     print (struct RData *)($arg0)
   else
+  if ($flags & RUBY_T_MASK) == RUBY_T_MOVED
+    printf "%sT_MOVED%s: ", $color_type, $color_end
+    print *(struct RMoved *)$arg0
+  else
     printf "%sunknown%s: ", $color_type, $color_end
     print (struct RBasic *)($arg0)
   end
@@ -261,6 +303,8 @@ define rp
   end
   end
   end
+  end
+  end
 end
 document rp
   Print a Ruby's VALUE.
@@ -292,6 +336,9 @@ define rp_id
   if $id == idLTLT
     printf "(:<<)\n"
   else
+  if $id == idGTGT
+    printf "(:>>)\n"
+  else
   if $id == idLE
     printf "(:<=)\n"
   else
@@ -319,6 +366,18 @@ define rp_id
   if $id == idASET
     printf "(:[]=)\n"
   else
+  if $id == idCOLON2
+    printf "(:'::')\n"
+  else
+  if $id == idANDOP
+    printf "(:&&)\n"
+  else
+  if $id == idOROP
+    printf "(:||)\n"
+  else
+  if $id == idANDDOT
+    printf "(:&.)\n"
+  else
     if $id <= tLAST_OP_ID
       printf "O"
     else
@@ -350,12 +409,13 @@ define rp_id
       end
     end
     printf "(%ld): ", $id
-    rb_numtable_entry global_symbols.id_str $id
-    if $rb_numtable_rec
-      rp_string $rb_numtable_rec
-    else
-      echo undef\n
-    end
+    print_id $id
+    echo \n
+  end
+  end
+  end
+  end
+  end
   end
   end
   end
@@ -378,16 +438,35 @@ document rp_id
   Print an ID.
 end
 
-define rp_string
+define output_string
   set $flags = ((struct RBasic*)($arg0))->flags
-  set print address off
-  output (char *)(($flags & RUBY_FL_USER1) ? \
+  set $len = ($flags & RUBY_FL_USER1) ? \
+          ((struct RString*)($arg0))->as.heap.len : \
+          (($flags & (RUBY_FL_USER2|RUBY_FL_USER3|RUBY_FL_USER4|RUBY_FL_USER5|RUBY_FL_USER6)) >> RUBY_FL_USHIFT+2)
+  if $len > 0
+    output *(char *)(($flags & RUBY_FL_USER1) ? \
 	    ((struct RString*)($arg0))->as.heap.ptr : \
-	    ((struct RString*)($arg0))->as.ary)
-  set print address on
-  printf " bytesize:%ld ", ($flags & RUBY_FL_USER1) ? \
+	    ((struct RString*)($arg0))->as.ary) @ $len
+  else
+    output ""
+  end
+end
+
+define print_string
+  set $flags = ((struct RBasic*)($arg0))->flags
+  set $len = ($flags & RUBY_FL_USER1) ? \
           ((struct RString*)($arg0))->as.heap.len : \
           (($flags & (RUBY_FL_USER2|RUBY_FL_USER3|RUBY_FL_USER4|RUBY_FL_USER5|RUBY_FL_USER6)) >> RUBY_FL_USHIFT+2)
+  if $len > 0
+    printf "%s", *(char *)(($flags & RUBY_FL_USER1) ? \
+	    ((struct RString*)($arg0))->as.heap.ptr : \
+	    ((struct RString*)($arg0))->as.ary) @ $len
+  end
+end
+
+define rp_string
+  output_string $arg0
+  printf " bytesize:%ld ", $len
   if !($flags & RUBY_FL_USER1)
     printf "(embed) "
   else
@@ -418,20 +497,109 @@ document rp_string
   Print the content of a String.
 end
 
+define rp_bignum
+  set $flags = ((struct RBignum*)($arg0))->basic.flags
+  set $len = (($flags & RUBY_FL_USER2) ? \
+       ($flags & (RUBY_FL_USER5|RUBY_FL_USER4|RUBY_FL_USER3)) >> (RUBY_FL_USHIFT+3) : \
+       ((struct RBignum*)($arg0))->as.heap.len)
+  printf "%sT_BIGNUM%s: sign=%d len=%ld ", $color_type, $color_end, \
+         (($flags & RUBY_FL_USER1) != 0), $len
+  if $flags & RUBY_FL_USER2
+    printf "(embed) "
+  end
+  print (struct RBignum *)($arg0)
+  set $ptr = (($flags & RUBY_FL_USER2) ? \
+              ((struct RBignum*)($arg0))->as.ary : \
+              ((struct RBignum*)($arg0))->as.heap.digits)
+  set $len = $len-1
+  printf "0x%x", $ptr[$len]
+  while $len > 0
+    set $len = $len-1
+    set $val = $ptr[$len]
+    set $w = sizeof($ptr[0])
+    printf "_"
+    if $w > 8
+      printf "%.32x", $val
+    else
+    if $w > 4
+      printf "%.16x", $val
+    else
+    if $w > 2
+      printf "%.8x", $val
+    else
+    if $w > 1
+      printf "%.4x", $val
+    else
+      printf "%.2x", $val
+    end
+    end
+    end
+    end
+  end
+  printf "\n"
+end
+document rp_bignum
+  Print the content of a Bignum.
+end
+
 define rp_class
   printf "(struct RClass *) %p", (void*)$arg0
-  if ((struct RClass *)($arg0))->ptr.origin != $arg0
-    printf " -> %p", ((struct RClass *)($arg0))->ptr.origin
+  if RCLASS_ORIGIN((struct RClass *)($arg0)) != $arg0
+    printf " -> %p", RCLASS_ORIGIN((struct RClass *)($arg0))
   end
   printf "\n"
   rb_classname $arg0
-  print *(struct RClass *)($arg0)
-  print *((struct RClass *)($arg0))->ptr
+  print/x *(struct RClass *)($arg0)
+  print *RCLASS_EXT((struct RClass *)($arg0))
 end
 document rp_class
   Print the content of a Class/Module.
 end
 
+define rp_imemo
+  set $flags = (enum imemo_type)((((struct RBasic *)($arg0))->flags >> RUBY_FL_USHIFT) & RUBY_IMEMO_MASK)
+  if $flags == imemo_cref
+    printf "(rb_cref_t *) %p\n", (void*)$arg0
+    print *(rb_cref_t *)$arg0
+  else
+  if $flags == imemo_svar
+    printf "(struct vm_svar *) %p\n", (void*)$arg0
+    print *(struct vm_svar *)$arg0
+  else
+  if $flags == imemo_throw_data
+    printf "(struct vm_throw_data *) %p\n", (void*)$arg0
+    print *(struct vm_throw_data *)$arg0
+  else
+  if $flags == imemo_ifunc
+    printf "(struct vm_ifunc *) %p\n", (void*)$arg0
+    print *(struct vm_ifunc *)$arg0
+  else
+  if $flags == imemo_memo
+    printf "(struct MEMO *) %p\n", (void*)$arg0
+    print *(struct MEMO *)$arg0
+  else
+  if $flags == imemo_ment
+    printf "(rb_method_entry_t *) %p\n", (void*)$arg0
+    print *(rb_method_entry_t *)$arg0
+  else
+  if $flags == imemo_iseq
+    printf "(rb_iseq_t *) %p\n", (void*)$arg0
+    print *(rb_iseq_t *)$arg0
+  else
+    printf "(struct RIMemo *) %p\n", (void*)$arg0
+    print *(struct RIMemo *)$arg0
+  end
+  end
+  end
+  end
+  end
+  end
+  end
+end
+document rp_imemo
+  Print the content of a memo
+end
+
 define nd_type
   print (enum node_type)((((NODE*)($arg0))->flags&RUBY_NODE_TYPEMASK)>>RUBY_NODE_TYPESHIFT)
 end
@@ -541,12 +709,6 @@ define nd_cval
   rp ($arg0).u3.value
 end
 
-
-define nd_cnt
-  printf "%su3.cnt%s: ", $color_highlite, $color_end
-  p ($arg0).u3.cnt
-end
-
 define nd_tbl
   printf "%su1.tbl%s: ", $color_highlite, $color_end
   p ($arg0).u1.tbl
@@ -585,12 +747,6 @@ define nd_lit
   rp ($arg0).u1.value
 end
 
-
-define nd_frml
-  printf "%su1.node%s: ", $color_highlite, $color_end
-  rp ($arg0).u1.node
-end
-
 define nd_rest
   printf "%su2.argc%s: ", $color_highlite, $color_end
   p ($arg0).u2.argc
@@ -617,12 +773,6 @@ define nd_args
   rp ($arg0).u3.node
 end
 
-
-define nd_noex
-  printf "%su1.id%s: ", $color_highlite, $color_end
-  p ($arg0).u1.id
-end
-
 define nd_defn
   printf "%su3.node%s: ", $color_highlite, $color_end
   rp ($arg0).u3.node
@@ -640,17 +790,6 @@ define nd_new
 end
 
 
-define nd_cfnc
-  printf "%su1.cfunc%s: ", $color_highlite, $color_end
-  p ($arg0).u1.cfunc
-end
-
-define nd_argc
-  printf "%su2.argc%s: ", $color_highlite, $color_end
-  p ($arg0).u2.argc
-end
-
-
 define nd_cname
   printf "%su1.id%s: ", $color_highlite, $color_end
   p ($arg0).u1.id
@@ -710,6 +849,12 @@ define nd_tval
   rp ($arg0).u2.value
 end
 
+define nd_tree
+  set $buf = (struct RString *)rb_str_buf_new(0)
+  call dump_node((VALUE)($buf), rb_str_tmp_new(0), 0, ($arg0))
+  printf "%s\n", $buf->as.heap.ptr
+end
+
 define rb_p
   call rb_p($arg0)
 end
@@ -731,7 +876,7 @@ define rb_numtable_entry
       end
     end
   else
-    set $rb_numtable_p = $rb_numtable_tbl->as.big.bins[$rb_numtable_id % $rb_numtable_tbl->num_bins]
+    set $rb_numtable_p = $rb_numtable_tbl->as.big.bins[st_numhash($rb_numtable_id) % $rb_numtable_tbl->num_bins]
     while $rb_numtable_p
       if $rb_numtable_p->key == $rb_numtable_id
 	set $rb_numtable_key = $rb_numtable_p->key
@@ -761,7 +906,7 @@ define rb_method_entry
     rb_numtable_entry $rb_method_entry_klass->m_tbl_wrapper->tbl $rb_method_entry_id
     set $rb_method_entry_me = (rb_method_entry_t *)$rb_numtable_rec
     if !$rb_method_entry_me
-      set $rb_method_entry_klass = (struct RClass *)$rb_method_entry_klass->ptr->super
+      set $rb_method_entry_klass = (struct RClass *)RCLASS_SUPER($rb_method_entry_klass)
     end
   end
   if $rb_method_entry_me
@@ -777,8 +922,7 @@ end
 
 define rb_classname
   # up to 128bit int
-  set $rb_classname_permanent = "0123456789ABCDEF"
-  set $rb_classname = classname($arg0, $rb_classname_permanent)
+  set $rb_classname = rb_mod_name($arg0)
   if $rb_classname != RUBY_Qnil
     rp $rb_classname
   else
@@ -790,7 +934,7 @@ define rb_ancestors
   set $rb_ancestors_module = $arg0
   while $rb_ancestors_module
     rp_class $rb_ancestors_module
-    set $rb_ancestors_module = ((struct RClass *)($rb_ancestors_module))->ptr.super
+    set $rb_ancestors_module = RCLASS_SUPER($rb_ancestors_module)
   end
 end
 document rb_ancestors
@@ -827,7 +971,7 @@ define iseq
 end
 
 define rb_ps
-  rb_ps_vm ruby_current_vm
+  rb_ps_vm ruby_current_vm_ptr
 end
 document rb_ps
 Dump all threads and their callstacks
@@ -835,36 +979,307 @@ end
 
 define rb_ps_vm
   print $ps_vm = (rb_vm_t*)$arg0
-  set $ps_threads = (st_table*)$ps_vm->living_threads
-  if $ps_threads->entries_packed
-    set $ps_threads_i = 0
-    while $ps_threads_i < $ps_threads->num_entries
-      set $ps_threads_key = (st_data_t)$ps_threads->as.packed.entries[$ps_threads_i].key
-      set $ps_threads_val = (st_data_t)$ps_threads->as.packed.entries[$ps_threads_i].val
-      rb_ps_thread $ps_threads_key $ps_threads_val
-      set $ps_threads_i = $ps_threads_i + 1
-    end
-  else
-    set $ps_threads_ptr = (st_table_entry*)$ps_threads->head
-    while $ps_threads_ptr
-      set $ps_threads_key = (st_data_t)$ps_threads_ptr->key
-      set $ps_threads_val = (st_data_t)$ps_threads_ptr->record
-      rb_ps_thread $ps_threads_key $ps_threads_val
-      set $ps_threads_ptr = (st_table_entry*)$ps_threads_ptr->fore
+  set $ps_thread_ln      = $ps_vm->ractor.main_ractor.threads.set.n.next
+  set $ps_thread_ln_last = $ps_vm->ractor.main_ractor.threads.set.n.prev
+  while 1
+    set $ps_thread_th = (rb_thread_t *)$ps_thread_ln
+    set $ps_thread = (VALUE)($ps_thread_th->self)
+    rb_ps_thread $ps_thread
+    if $ps_thread_ln == $ps_thread_ln_last
+      loop_break
     end
+    set $ps_thread_ln = $ps_thread_ln->next
   end
 end
 document rb_ps_vm
 Dump all threads in a (rb_vm_t*) and their callstacks
 end
 
-define rb_ps_thread
-  set $ps_thread = (struct RTypedData*)$arg0
-  set $ps_thread_id = $arg1
-  print $ps_thread_th = (rb_thread_t*)$ps_thread->data
+define print_lineno
+  set $cfp = $arg0
+  set $iseq = $cfp->iseq
+  set $pos = $cfp->pc - $iseq->body->iseq_encoded
+  if $pos != 0
+    set $pos = $pos - 1
+  end
+
+  set $index = 0
+  set $size = $iseq->body->insns_info.size
+  set $table = $iseq->body->insns_info.body
+  set $positions = $iseq->body->insns_info.positions
+  #printf "size: %d\n", $size
+  if $size == 0
+  else
+  if $size == 1
+    printf "%d", $table[0].line_no
+  else
+    if $positions
+      # get_insn_info_linear_search
+      set $index = 1
+      while $index < $size
+        #printf "table[%d]: position: %d, line: %d, pos: %d\n", $i, $positions[$i], $table[$i].line_no, $pos
+        if $positions[$index] > $pos
+          loop_break
+        end
+        set $index = $index + 1
+        if $positions[$index] == $pos
+          loop_break
+        end
+      end
+    else
+      # get_insn_info_succinct_bitvector
+      set $sd = $iseq->body->insns_info.succ_index_table
+      set $immediate_table_size = sizeof($sd->imm_part) / sizeof(uint64_t) * 9
+      if $pos < $immediate_table_size
+        set $i = $pos / 9
+        set $j = $pos % 9
+        set $index = ((int)($sd->imm_part[$i] >> ($j * 7))) & 0x7f
+      else
+        set $block_index = ($pos - $immediate_table_size) / 512
+        set $block = &$sd->succ_part[$block_index]
+        set $block_bit_index = ($pos - $immediate_table_size) % 512
+        set $small_block_index = $block_bit_index / 64
+        set $small_block_popcount = $small_block_index == 0 ? 0 : (((int)($block->small_block_ranks >> (($small_block_index - 1) * 9))) & 0x1ff)
+        set $x = $block->bits[$small_block_index] << (63 - $block_bit_index % 64)
+        set $x = ($x & 0x5555555555555555) + ($x >> 1 & 0x5555555555555555)
+        set $x = ($x & 0x3333333333333333) + ($x >> 2 & 0x3333333333333333)
+        set $x = ($x & 0x0707070707070707) + ($x >> 4 & 0x0707070707070707)
+        set $x = ($x & 0x001f001f001f001f) + ($x >> 8 & 0x001f001f001f001f)
+        set $x = ($x & 0x0000003f0000003f) + ($x >>16 & 0x0000003f0000003f)
+        set $popcnt = ($x & 0x7f) + ($x >>32 & 0x7f)
+        set $index = $block->rank + $small_block_popcount + $popcnt
+      end
+    end
+    printf "%d", $table[$index-1].line_no
+  end
+  end
 end
 
-# Details: https://bugs.ruby-lang.org/projects/ruby-trunk/wiki/MachineInstructionsTraceWithGDB
+define check_method_entry
+  set $imemo = (struct RBasic *)$arg0
+  if $imemo != RUBY_Qfalse
+    set $type = ($imemo->flags >> 12) & 0x07
+    if $type == imemo_ment
+      set $me = (rb_callable_method_entry_t *)$imemo
+    else
+    if $type == imemo_svar
+      set $imemo = ((struct vm_svar *)$imemo)->cref_or_me
+      check_method_entry $imemo
+    end
+    end
+  end
+end
+
+define print_id
+  set $id = $arg0
+  # rb_id_to_serial
+  if $id > tLAST_OP_ID
+    set $serial = (rb_id_serial_t)($id >> RUBY_ID_SCOPE_SHIFT)
+  else
+    set $serial = (rb_id_serial_t)$id
+  end
+  if $serial && $serial <= ruby_global_symbols.last_id
+    set $idx = $serial / ID_ENTRY_UNIT
+    set $ids = (struct RArray *)ruby_global_symbols.ids
+    set $flags = $ids->basic.flags
+    if ($flags & RUBY_FL_USER1)
+      set $idsptr = $ids->as.ary
+      set $idslen = (($flags & (RUBY_FL_USER3|RUBY_FL_USER4)) >> (RUBY_FL_USHIFT+3))
+    else
+      set $idsptr = $ids->as.heap.ptr
+      set $idslen = $ids->as.heap.len
+    end
+    if $idx < $idslen
+      set $t = 0
+      set $ary = (struct RArray *)$idsptr[$idx]
+      if $ary != RUBY_Qnil
+        set $flags = $ary->basic.flags
+        if ($flags & RUBY_FL_USER1)
+          set $aryptr = $ary->as.ary
+          set $arylen = (($flags & (RUBY_FL_USER3|RUBY_FL_USER4)) >> (RUBY_FL_USHIFT+3))
+        else
+          set $aryptr = $ary->as.heap.ptr
+          set $arylen = $ary->as.heap.len
+        end
+        set $result = $aryptr[($serial % ID_ENTRY_UNIT) * ID_ENTRY_SIZE + $t]
+        if $result != RUBY_Qnil
+          print_string $result
+        else
+          echo undef
+        end
+      end
+    end
+  end
+end
+
+define print_pathobj
+  set $flags = ((struct RBasic*)($arg0))->flags
+  if ($flags & RUBY_T_MASK) == RUBY_T_STRING
+    print_string $arg0
+  end
+  if ($flags & RUBY_T_MASK) == RUBY_T_ARRAY
+    if $flags & RUBY_FL_USER1
+      set $str = ((struct RArray*)($arg0))->as.ary[0]
+    else
+      set $str = ((struct RArray*)($arg0))->as.heap.ptr[0]
+    end
+    print_string $str
+  end
+end
+
+define rb_ps_thread
+  set $ps_thread = (struct RTypedData*)$arg0
+  set $ps_thread_th = (rb_thread_t*)$ps_thread->data
+  printf "* #<Thread:%p rb_thread_t:%p native_thread:%p>\n", \
+    $ps_thread, $ps_thread_th, $ps_thread_th->thread_id
+  set $cfp = $ps_thread_th->ec->cfp
+  set $cfpend = (rb_control_frame_t *)($ps_thread_th->ec->vm_stack + $ps_thread_th->ec->vm_stack_size)-1
+  while $cfp < $cfpend
+    if $cfp->iseq
+      if !((VALUE)$cfp->iseq & RUBY_IMMEDIATE_MASK) && (((imemo_ifunc << RUBY_FL_USHIFT) | RUBY_T_IMEMO)==$cfp->iseq->flags & ((RUBY_IMEMO_MASK << RUBY_FL_USHIFT) | RUBY_T_MASK))
+        printf "%d:ifunc ", $cfpend-$cfp
+        set print symbol-filename on
+        output/a $cfp->iseq.body
+        set print symbol-filename off
+        printf "\n"
+      else
+      if $cfp->pc
+        set $location = $cfp->iseq->body->location
+        printf "%d:", $cfpend-$cfp
+        print_pathobj $location.pathobj
+        printf ":"
+        print_lineno $cfp
+        printf ":in `"
+        print_string $location.label
+        printf "'\n"
+      else
+        printf "%d: ???.rb:???:in `???'\n", $cfpend-$cfp
+      end
+      end
+    else
+      # if VM_FRAME_TYPE($cfp->flag) == VM_FRAME_MAGIC_CFUNC
+      set $ep = $cfp->ep
+      if ($ep[0] & 0xffff0001) == 0x55550001
+        #define VM_ENV_FLAG_LOCAL 0x02
+        #define VM_ENV_PREV_EP(ep)   GC_GUARDED_PTR_REF(ep[VM_ENV_DATA_INDEX_SPECVAL])
+        set $me = 0
+        set $env_specval = $ep[-1]
+        set $env_me_cref = $ep[-2]
+        while ($env_specval & 0x02) != 0
+          check_method_entry $env_me_cref
+          if $me != 0
+            loop_break
+          end
+          set $ep = $ep[0]
+          set $env_specval = $ep[-1]
+          set $env_me_cref = $ep[-2]
+        end
+        if $me == 0
+          check_method_entry $env_me_cref
+        end
+        printf "%d:", $cfpend-$cfp
+        set print symbol-filename on
+        output/a $me->def->body.cfunc.func
+        set print symbol-filename off
+        set $mid = $me->def->original_id
+        printf ":in `"
+        print_id $mid
+        printf "'\n"
+      else
+        printf "%d:unknown_frame:???:in `???'\n", $cfpend-$cfp
+      end
+    end
+    set $cfp = $cfp + 1
+  end
+end
+
+define rb_count_objects
+  set $objspace = ruby_current_vm_ptr->objspace
+  set $counts_00 = 0
+  set $counts_01 = 0
+  set $counts_02 = 0
+  set $counts_03 = 0
+  set $counts_04 = 0
+  set $counts_05 = 0
+  set $counts_06 = 0
+  set $counts_07 = 0
+  set $counts_08 = 0
+  set $counts_09 = 0
+  set $counts_0a = 0
+  set $counts_0b = 0
+  set $counts_0c = 0
+  set $counts_0d = 0
+  set $counts_0e = 0
+  set $counts_0f = 0
+  set $counts_10 = 0
+  set $counts_11 = 0
+  set $counts_12 = 0
+  set $counts_13 = 0
+  set $counts_14 = 0
+  set $counts_15 = 0
+  set $counts_16 = 0
+  set $counts_17 = 0
+  set $counts_18 = 0
+  set $counts_19 = 0
+  set $counts_1a = 0
+  set $counts_1b = 0
+  set $counts_1c = 0
+  set $counts_1d = 0
+  set $counts_1e = 0
+  set $counts_1f = 0
+  set $total = 0
+  set $i = 0
+  while $i < $objspace->heap_pages.allocated_pages
+    printf "\rcounting... %d/%d", $i, $objspace->heap_pages.allocated_pages
+    set $page = $objspace->heap_pages.sorted[$i]
+    set $p = $page->start
+    set $pend = $p + $page->total_slots
+    while $p < $pend
+      set $flags = $p->as.basic.flags & 0x1f
+      eval "set $counts_%02x = $counts_%02x + 1", $flags, $flags
+      set $p = $p + 1
+    end
+    set $total = $total + $page->total_slots
+    set $i = $i + 1
+  end
+  printf "\rTOTAL: %d, FREE: %d\n", $total, $counts_00
+  printf "T_OBJECT: %d\n", $counts_01
+  printf "T_CLASS: %d\n", $counts_02
+  printf "T_MODULE: %d\n", $counts_03
+  printf "T_FLOAT: %d\n", $counts_04
+  printf "T_STRING: %d\n", $counts_05
+  printf "T_REGEXP: %d\n", $counts_06
+  printf "T_ARRAY: %d\n", $counts_07
+  printf "T_HASH: %d\n", $counts_08
+  printf "T_STRUCT: %d\n", $counts_09
+  printf "T_BIGNUM: %d\n", $counts_0a
+  printf "T_FILE: %d\n", $counts_0b
+  printf "T_DATA: %d\n", $counts_0c
+  printf "T_MATCH: %d\n", $counts_0d
+  printf "T_COMPLEX: %d\n", $counts_0e
+  printf "T_RATIONAL: %d\n", $counts_0f
+  #printf "UNKNOWN_10: %d\n", $counts_10
+  printf "T_NIL: %d\n", $counts_11
+  printf "T_TRUE: %d\n", $counts_12
+  printf "T_FALSE: %d\n", $counts_13
+  printf "T_SYMBOL: %d\n", $counts_14
+  printf "T_FIXNUM: %d\n", $counts_15
+  printf "T_UNDEF: %d\n", $counts_16
+  #printf "UNKNOWN_17: %d\n", $counts_17
+  #printf "UNKNOWN_18: %d\n", $counts_18
+  #printf "UNKNOWN_19: %d\n", $counts_19
+  printf "T_IMEMO: %d\n", $counts_1a
+  printf "T_NODE: %d\n", $counts_1b
+  printf "T_ICLASS: %d\n", $counts_1c
+  printf "T_ZOMBIE: %d\n", $counts_1d
+  #printf "UNKNOWN_1E: %d\n", $counts_1e
+  printf "T_MASK: %d\n", $counts_1f
+end
+document rb_count_objects
+  Counts all objects grouped by type.
+end
+
+# Details: https://bugs.ruby-lang.org/projects/ruby-master/wiki/MachineInstructionsTraceWithGDB
 define trace_machine_instructions
   set logging on
   set height 0
@@ -880,3 +1295,56 @@ define SDR
   call rb_vmdebug_stack_dump_raw_current()
 end
 
+define rbi
+  if ((LINK_ELEMENT*)$arg0)->type == ISEQ_ELEMENT_LABEL
+    p *(LABEL*)$arg0
+  else
+  if ((LINK_ELEMENT*)$arg0)->type == ISEQ_ELEMENT_INSN
+    p *(INSN*)$arg0
+  else
+  if ((LINK_ELEMENT*)$arg0)->type == ISEQ_ELEMENT_ADJUST
+    p *(ADJUST*)$arg0
+  else
+    print *$arg0
+  end
+  end
+  end
+end
+
+define dump_node
+  set $str = rb_parser_dump_tree($arg0, 0)
+  set $flags = ((struct RBasic*)($str))->flags
+  printf "%s", (char *)(($flags & RUBY_FL_USER1) ? \
+                        ((struct RString*)$str)->as.heap.ptr : \
+                        ((struct RString*)$str)->as.ary)
+end
+
+define print_flags
+  printf "RUBY_FL_WB_PROTECTED: %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_WB_PROTECTED ? "1" : "0"
+  printf "RUBY_FL_PROMOTED0   : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_PROMOTED0 ? "1" : "0"
+  printf "RUBY_FL_PROMOTED1   : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_PROMOTED1 ? "1" : "0"
+  printf "RUBY_FL_FINALIZE    : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_FINALIZE ? "1" : "0"
+  printf "RUBY_FL_SHAREABLE   : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_SHAREABLE ? "1" : "0"
+  printf "RUBY_FL_EXIVAR      : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_EXIVAR ? "1" : "0"
+  printf "RUBY_FL_FREEZE      : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_FREEZE ? "1" : "0"
+
+  printf "RUBY_FL_USER0       : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_USER0 ? "1" : "0"
+  printf "RUBY_FL_USER1       : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_USER1 ? "1" : "0"
+  printf "RUBY_FL_USER2       : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_USER2 ? "1" : "0"
+  printf "RUBY_FL_USER3       : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_USER3 ? "1" : "0"
+  printf "RUBY_FL_USER4       : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_USER4 ? "1" : "0"
+  printf "RUBY_FL_USER5       : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_USER5 ? "1" : "0"
+  printf "RUBY_FL_USER6       : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_USER6 ? "1" : "0"
+  printf "RUBY_FL_USER7       : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_USER7 ? "1" : "0"
+  printf "RUBY_FL_USER8       : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_USER8 ? "1" : "0"
+  printf "RUBY_FL_USER9       : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_USER9 ? "1" : "0"
+  printf "RUBY_FL_USER10      : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_USER10 ? "1" : "0"
+  printf "RUBY_FL_USER11      : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_USER11 ? "1" : "0"
+  printf "RUBY_FL_USER12      : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_USER12 ? "1" : "0"
+  printf "RUBY_FL_USER13      : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_USER13 ? "1" : "0"
+  printf "RUBY_FL_USER14      : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_USER14 ? "1" : "0"
+  printf "RUBY_FL_USER15      : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_USER15 ? "1" : "0"
+  printf "RUBY_FL_USER16      : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_USER16 ? "1" : "0"
+  printf "RUBY_FL_USER17      : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_USER17 ? "1" : "0"
+  printf "RUBY_FL_USER18      : %s\n", ((struct RBasic*)($arg0))->flags & RUBY_FL_USER18 ? "1" : "0"
+end
diff --git a/.git-blame-ignore-revs b/.git-blame-ignore-revs
new file mode 100644
index 0000000000..6c5eac5a0f
--- /dev/null
+++ b/.git-blame-ignore-revs
@@ -0,0 +1,23 @@
+# This is a file used by GitHub to ignore the following commits on `git blame`.
+#
+# You can also do the same thing in your local repository with:
+# $ git config --local blame.ignoreRevsFile .git-blame-ignore-revs
+
+# Expand tabs
+5b21e94bebed90180d8ff63dad03b8b948361089
+
+# Enable Style/StringLiterals cop for RubyGems/Bundler
+d7ffd3fea402239b16833cc434404a7af82d44f3
+
+# [ruby/digest] Revert tab-expansion in external files
+48b09aae7ec5632209229dcc294dd0d75a93a17f
+8a65cf3b61c60e4cb886f59a73ff6db44364bfa9
+39dc9f9093901d40d2998653948d5da38b18ee2c
+
+# [ruby/io-nonblock] Revert tab expansion
+f28287d34c03f472ffe90ea262bdde9affd4b965
+0d842fecb4f75ab3b1d4097ebdb8e88f51558041
+4ba2c66761d6a293abdfba409241d31063cefd62
+
+# Make benchmark indentation consistent
+fc4acf8cae82e5196186d3278d831f2438479d91
diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000000..d0c2d266b4
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,8 @@
+*.gemspec diff=ruby
+*.rb diff=ruby
+bin svn-properties=svn:ignore=ruby
+bin/* diff=ruby
+tool/update-deps diff=ruby
+tool/make-snapshot diff=ruby
+tool/format-release diff=ruby
+tool/leaked-globals diff=ruby
diff --git a/.github/SECURITY.md b/.github/SECURITY.md
new file mode 100644
index 0000000000..56baa29942
--- /dev/null
+++ b/.github/SECURITY.md
@@ -0,0 +1,9 @@
+# Security Policy
+
+## Supported Versions
+
+See <https://www.ruby-lang.org/en/downloads/branches/>.
+
+## Reporting a Vulnerability
+
+See <https://www.ruby-lang.org/en/security/>.
diff --git a/.github/codeql/codeql-config.yml b/.github/codeql/codeql-config.yml
new file mode 100644
index 0000000000..91f82b842b
--- /dev/null
+++ b/.github/codeql/codeql-config.yml
@@ -0,0 +1,3 @@
+name: "CodeQL config for the Ruby language"
+
+languages: cpp
diff --git a/.github/dependabot.yml b/.github/dependabot.yml
new file mode 100644
index 0000000000..bc63aca35b
--- /dev/null
+++ b/.github/dependabot.yml
@@ -0,0 +1,6 @@
+version: 2
+updates:
+  - package-ecosystem: 'github-actions'
+    directory: '/'
+    schedule:
+      interval: 'monthly'
diff --git a/.github/workflows/baseruby.yml b/.github/workflows/baseruby.yml
new file mode 100644
index 0000000000..ebaafe3bf0
--- /dev/null
+++ b/.github/workflows/baseruby.yml
@@ -0,0 +1,80 @@
+name: BASERUBY Check
+
+on:
+  push:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+  pull_request:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+  merge_group:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:
+  contents: read
+
+jobs:
+  baseruby:
+    name: BASERUBY
+    runs-on: ubuntu-22.04
+    if: ${{ !contains(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
+    strategy:
+      matrix:
+        ruby:
+          - ruby-2.2
+#         - ruby-2.3
+#         - ruby-2.4
+#         - ruby-2.5
+#         - ruby-2.6
+#         - ruby-2.7
+          - ruby-3.0
+          - ruby-3.1
+
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+        with:
+          path: .downloaded-cache
+          key: downloaded-cache
+      - uses: ruby/setup-ruby@13e7a03dc3ac6c3798f4570bfead2aed4d96abfb # v1.244.0
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          bundler: none
+      - run: echo "GNUMAKEFLAGS=-j$((1 + $(nproc --all)))" >> $GITHUB_ENV
+      - run: sudo apt-get install build-essential autoconf bison libyaml-dev
+      - run: ./autogen.sh
+      - run: ./configure --disable-install-doc
+      - run: make common-srcs
+      - run: make incs
+      - run: make all
+      - run: make test
+      - uses: ruby/action-slack@0bd85c72233cdbb6a0fe01d37aaeff1d21b5fce1 # v3.2.1
+        with:
+          payload: |
+            {
+              "ci": "GitHub Actions",
+              "env": "${{ github.workflow }} / BASERUBY @ ${{ matrix.ruby }}",
+              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
+              "commit": "${{ github.sha }}",
+              "branch": "${{ github.ref_name }}"
+            }
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() && github.event_name == 'push' }}
diff --git a/.github/workflows/bundled_gems.yml b/.github/workflows/bundled_gems.yml
new file mode 100644
index 0000000000..070c0fa1dd
--- /dev/null
+++ b/.github/workflows/bundled_gems.yml
@@ -0,0 +1,166 @@
+name: bundled_gems
+
+on:
+  push:
+    branches: [ "master" ]
+    paths:
+      - '.github/workflows/bundled_gems.yml'
+      - 'gems/bundled_gems'
+  pull_request:
+    branches: [ "master" ]
+    paths:
+      - '.github/workflows/bundled_gems.yml'
+      - 'gems/bundled_gems'
+  merge_group:
+    branches: [ "master" ]
+    paths:
+      - '.github/workflows/bundled_gems.yml'
+      - 'gems/bundled_gems'
+  schedule:
+    - cron: '45 6 * * *'
+  workflow_dispatch:
+
+permissions:  # added using https://github.com/step-security/secure-workflows
+  contents: read
+
+jobs:
+  update:
+    permissions:
+      contents: write  # for Git to git push
+    if: ${{ github.event_name != 'schedule' || github.repository == 'ruby/ruby' }}
+    name: update ${{ github.workflow }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: git config
+        run: |
+          git config --global advice.detachedHead 0
+          git config --global init.defaultBranch garbage
+
+      - name: Set ENV
+        run: |
+          echo "GNUMAKEFLAGS=-j$((1 + $(nproc --all)))" >> $GITHUB_ENV
+          echo "TODAY=$(date +%F)" >> $GITHUB_ENV
+
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+
+      - uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+        with:
+          path: .downloaded-cache
+          key: downloaded-cache-${{ github.sha }}
+          restore-keys: |
+            downloaded-cache
+
+      - name: Download previous gems list
+        run: |
+          data=bundled_gems.json
+          mkdir -p .downloaded-cache
+          ln -s .downloaded-cache/$data .
+          curl -O -R -z ./$data https://stdgems.org/$data
+
+      - name: Update bundled gems list
+        run: |
+          ruby -i~ tool/update-bundled_gems.rb gems/bundled_gems
+
+      - name: Maintain updated gems list in NEWS
+        run: |
+          #!ruby
+          require 'json'
+          news = File.read("NEWS.md")
+          prev = news[/since the \*+(\d+\.\d+\.\d+)\*+/, 1]
+          prevs = [prev, prev.sub(/\.\d+\z/, '')]
+          %W[bundled].each do |type|
+            last = JSON.parse(File.read("#{type}_gems.json"))['gems'].filter_map do |g|
+              v = g['versions'].values_at(*prevs).compact.first
+              g = g['gem']
+              g = 'RubyGems' if g == 'rubygems'
+              [g, v] if v
+            end.to_h
+            changed = File.foreach("gems/#{type}_gems").filter_map do |l|
+              next if l.start_with?("#")
+              g, v = l.split(" ", 3)
+              [g, v] unless last[g] == v
+            end
+            changed, added = changed.partition {|g, _| last[g]}
+            news.sub!(/^\*( +)The following #{type} gems? are updated\.\n+\K(?: \1\*( +).*\n)*/) do
+              mark = "#{$1} *#{$2}"
+              changed.map {|g, v|"#{mark}#{g} #{v}\n"}.join("")
+            end or next
+            news.sub!(/^\*( +)The following default gems are now bundled gems\.\n+\K(?: \1\*( +).*\n)*/) do
+              mark = "#{$1} *#{$2}"
+              added.map {|g, v|"#{mark}#{g} #{v}\n"}.join("")
+            end or next unless added.empty?
+            File.write("NEWS.md", news)
+          end
+        shell: ruby {0}
+
+      - name: Check diffs
+        id: diff
+        run: |
+          git add -- NEWS.md
+          git diff --no-ext-diff --ignore-submodules --quiet -- gems/bundled_gems
+        continue-on-error: true
+
+      - name: Install libraries
+        run: |
+          set -x
+          sudo apt-get update -q || :
+          sudo apt-get install --no-install-recommends -q -y build-essential libssl-dev libyaml-dev libreadline6-dev zlib1g-dev libncurses5-dev libffi-dev bison autoconf ruby
+        if: ${{ steps.diff.outcome == 'failure' }}
+
+      - name: Build
+        run: |
+          ./autogen.sh
+          ./configure -C --disable-install-doc
+          make
+        if: ${{ steps.diff.outcome == 'failure' }}
+
+      - name: Prepare bundled gems
+        run: |
+          make -s prepare-gems
+        if: ${{ steps.diff.outcome == 'failure' }}
+
+      - name: Test bundled gems
+        run: |
+          make -s test-bundled-gems
+          git add -- gems/bundled_gems
+        timeout-minutes: 30
+        env:
+          RUBY_TESTOPTS: "-q --tty=no"
+          TEST_BUNDLED_GEMS_ALLOW_FAILURES: ""
+        if: ${{ steps.diff.outcome == 'failure' }}
+
+      - name: Show diffs
+        id: show
+        run: |
+          git diff --cached --color --no-ext-diff --ignore-submodules --exit-code --
+        continue-on-error: true
+
+      - name: Commit
+        run: |
+          git pull --ff-only origin ${GITHUB_REF#refs/heads/}
+          message="Update bundled gems list at "
+          if [ ${{ steps.diff.outcome }} = success ]; then
+            git commit --message="${message}${GITHUB_SHA:0:30} [ci skip]"
+          else
+            git commit --message="${message}${TODAY}"
+          fi
+          git push origin ${GITHUB_REF#refs/heads/}
+        env:
+          EMAIL: svn-admin@ruby-lang.org
+          GIT_AUTHOR_NAME: git
+          GIT_COMMITTER_NAME: git
+        if: ${{ github.repository == 'ruby/ruby' && !startsWith(github.event_name, 'pull') && steps.show.outcome == 'failure' }}
+
+      - uses: ruby/action-slack@0bd85c72233cdbb6a0fe01d37aaeff1d21b5fce1 # v3.2.1
+        with:
+          payload: |
+            {
+              "ci": "GitHub Actions",
+              "env": "${{ github.workflow }} / update",
+              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
+              "commit": "${{ github.sha }}",
+              "branch": "${{ github.ref_name }}"
+            }
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() && github.event_name == 'push' }}
diff --git a/.github/workflows/check_dependencies.yml b/.github/workflows/check_dependencies.yml
new file mode 100644
index 0000000000..79b2916feb
--- /dev/null
+++ b/.github/workflows/check_dependencies.yml
@@ -0,0 +1,78 @@
+name: Check Dependencies
+on:
+  push:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+  pull_request:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+  merge_group:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:
+  contents: read
+
+jobs:
+  update-deps:
+    strategy:
+      matrix:
+        os: [ubuntu-22.04]
+      fail-fast: true
+    runs-on: ${{ matrix.os }}
+    if: ${{ !contains(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
+    steps:
+      - name: Install libraries
+        run: |
+          set -x
+          sudo apt-get update -q || :
+          sudo apt-get install --no-install-recommends -q -y build-essential libssl-dev libyaml-dev libreadline6-dev zlib1g-dev libncurses5-dev libffi-dev bison autoconf ruby
+        if: ${{ contains(matrix.os, 'ubuntu') }}
+      - name: Install libraries
+        run: |
+          brew install gmp libffi openssl@1.1 zlib autoconf automake libtool readline
+        if: ${{ contains(matrix.os, 'macos') }}
+      - name: git config
+        run: |
+          git config --global advice.detachedHead 0
+          git config --global init.defaultBranch garbage
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+        with:
+          path: .downloaded-cache
+          key: downloaded-cache
+      - run: ./autogen.sh
+      - name: Run configure
+        run: ./configure -C --disable-install-doc --disable-rubygems --with-gcc 'optflags=-O0' 'debugflags=-save-temps=obj -g'
+      - run: make all golf
+      - run: ruby tool/update-deps --fix
+      - run: git diff --no-ext-diff --ignore-submodules --exit-code
+      - uses: ruby/action-slack@0bd85c72233cdbb6a0fe01d37aaeff1d21b5fce1 # v3.2.1
+        with:
+          payload: |
+            {
+              "ci": "GitHub Actions",
+              "env": "${{ matrix.os }} / Dependencies need to update",
+              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
+              "commit": "${{ github.sha }}",
+              "branch": "${{ github.ref_name }}"
+            }
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() && github.event_name == 'push' }}
diff --git a/.github/workflows/codeql-analysis.yml b/.github/workflows/codeql-analysis.yml
new file mode 100644
index 0000000000..8dba76fbe2
--- /dev/null
+++ b/.github/workflows/codeql-analysis.yml
@@ -0,0 +1,75 @@
+name: "Code scanning - action"
+
+on:
+  # push:
+  #   paths-ignore:
+  #     - 'doc/**'
+  #     - '**/man'
+  #     - '**.md'
+  #     - '**.rdoc'
+  #     - '**/.document'
+  # pull_request:
+  #   paths-ignore:
+  #     - 'doc/**'
+  #     - '**/man'
+  #     - '**.md'
+  #     - '**.rdoc'
+  #     - '**/.document'
+  schedule:
+    - cron: '0 12 * * *'
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:  # added using https://github.com/step-security/secure-workflows
+  contents: read
+
+jobs:
+  CodeQL-Build:
+
+    # CodeQL runs on ubuntu-latest and windows-latest
+    permissions:
+      actions: read  # for github/codeql-action/init to get workflow details
+      contents: read  # for actions/checkout to fetch code
+      security-events: write  # for github/codeql-action/autobuild to send a status report
+    runs-on: ubuntu-latest
+    # CodeQL fails to run pull requests from dependabot due to missing write access to upload results.
+    if: ${{ !contains(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') && github.event.head_commit.pusher.name != 'dependabot[bot]' }}
+
+    env:
+      enable_install_doc: no
+
+    steps:
+    - name: Install libraries
+      run: |
+        set -x
+        sudo apt-get update -q || :
+        sudo apt-get install --no-install-recommends -q -y build-essential libssl-dev libyaml-dev libreadline6-dev zlib1g-dev libncurses5-dev libffi-dev bison autoconf ruby
+
+    - name: Checkout repository
+      uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+
+    - uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+      with:
+        path: .downloaded-cache
+        key: downloaded-cache
+
+    - name: Remove an obsolete rubygems vendored file
+      run: sudo rm /usr/lib/ruby/vendor_ruby/rubygems/defaults/operating_system.rb
+
+    - name: Initialize CodeQL
+      uses: github/codeql-action/init@959cbb7472c4d4ad70cdfe6f4976053fe48ab394 # v2.1.37
+      with:
+        config-file: ./.github/codeql/codeql-config.yml
+        trap-caching: false
+
+    - name: Set ENV
+      run: echo "GNUMAKEFLAGS=-j$((1 + $(nproc --all)))" >> $GITHUB_ENV
+
+    - name: Autobuild
+      uses: github/codeql-action/autobuild@959cbb7472c4d4ad70cdfe6f4976053fe48ab394 # v2.1.37
+
+    - name: Perform CodeQL Analysis
+      uses: github/codeql-action/analyze@959cbb7472c4d4ad70cdfe6f4976053fe48ab394 # v2.1.37
diff --git a/.github/workflows/compilers.yml b/.github/workflows/compilers.yml
new file mode 100644
index 0000000000..caf12cc0f4
--- /dev/null
+++ b/.github/workflows/compilers.yml
@@ -0,0 +1,281 @@
+name: Compilations
+
+on:
+  push:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+  pull_request:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.rdoc'
+      - '**/.document'
+  merge_group:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.rdoc'
+      - '**/.document'
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+# GitHub actions does not support YAML anchors.  This creative use of
+# environment variables (plus the "echo $GITHUB_ENV" hack) is to reroute that
+# restriction.
+env:
+  default_cc: clang-15
+  append_cc: ''
+
+  # -O1 is faster than -O3 in our tests... Majority of time are consumed trying
+  # to optimize binaries.  Also GitHub Actions run on relatively modern CPUs
+  # compared to, say, GCC 4 or Clang 3.  We don't specify `-march=native`
+  # because compilers tend not understand what the CPU is.
+  optflags: '-O1'
+
+  # -g0 disables backtraces when SEGV.  Do not set that.
+  debugflags: '-ggdb3'
+
+  default_configure: >-
+    --enable-debug-env
+    --disable-install-doc
+    --with-ext=-test-/cxxanyargs,+
+  append_configure: >-
+    --without-valgrind
+    --without-jemalloc
+    --without-gmp
+
+  UPDATE_UNICODE: >-
+    UNICODE_FILES=.
+    UNICODE_PROPERTY_FILES=.
+    UNICODE_AUXILIARY_FILES=.
+    UNICODE_EMOJI_FILES=.
+  CONFIGURE_TTY: never
+  GITPULLOPTIONS: --no-tags origin ${{github.ref}}
+  RUBY_DEBUG: ci rgengc
+  RUBY_TESTOPTS: >-
+    -q
+    --color=always
+    --tty=no
+
+permissions:
+  contents: read
+
+jobs:
+  compile:
+    strategy:
+      fail-fast: false
+      matrix:
+        env:
+          - {}
+        entry:
+          - { name: gcc-12,    env: { default_cc: gcc-12 } }
+          - { name: gcc-11,    env: { default_cc: gcc-11 } }
+          - { name: gcc-10,    env: { default_cc: gcc-10 } }
+          - { name: gcc-9,     env: { default_cc: gcc-9 } }
+          - { name: gcc-8,     env: { default_cc: gcc-8 } }
+          - { name: gcc-7,     env: { default_cc: gcc-7 } }
+          - name: 'gcc-13 LTO'
+            container: gcc-13
+            env:
+              default_cc: 'gcc-13 -flto=auto -ffat-lto-objects -Werror=lto-type-mismatch'
+              optflags: '-O2'
+            shared: disable
+            # check: true
+          - { name: clang-16,  env: { default_cc: clang-16 } }
+          - { name: clang-15,  env: { default_cc: clang-15 } }
+          - { name: clang-14,  env: { default_cc: clang-14 } }
+          - { name: clang-13,  env: { default_cc: clang-13 } }
+          - { name: clang-12,  env: { default_cc: clang-12 } }
+          - { name: clang-11,  env: { default_cc: clang-11 } }
+          - { name: clang-10,  env: { default_cc: clang-10 } }
+          # llvm-objcopy<=9 doesn't have --wildcard. It compiles, but leaves Rust symbols in libyjit.o.
+          - { name: clang-9,   env: { default_cc: clang-9,   append_configure: '--disable-yjit' } }
+          - { name: clang-8,   env: { default_cc: clang-8,   append_configure: '--disable-yjit' } }
+          - { name: clang-7,   env: { default_cc: clang-7,   append_configure: '--disable-yjit' } }
+          - { name: clang-6.0, env: { default_cc: clang-6.0, append_configure: '--disable-yjit' } }
+          - name: 'clang-16 LTO'
+            container: clang-16
+            env:
+              default_cc: 'clang-16 -flto=auto'
+              optflags: '-O2'
+            shared: disable
+            # check: true
+
+#         - { name: aarch64-linux-gnu,     crosshost: aarch64-linux-gnu, container: crossbuild-essential-arm64 }
+#         - { name: arm-linux-gnueabi,     crosshost: arm-linux-gnueabi }
+#         - { name: arm-linux-gnueabihf,   crosshost: arm-linux-gnueabihf }
+#         - { name: i686-w64-mingw32,      crosshost: i686-w64-mingw32 }
+#         - { name: powerpc-linux-gnu,     crosshost: powerpc-linux-gnu }
+#         - { name: powerpc64le-linux-gnu, crosshost: powerpc64le-linux-gnu, container: crossbuild-essential-ppc64el }
+#         - { name: s390x-linux-gnu,       crosshost: s390x-linux-gnu, container: crossbuild-essential-s390x }
+#         - { name: x86_64-w64-mingw32,    crosshost: x86_64-w64-mingw32, container: mingw-w64 }
+
+          # -Wno-strict-prototypes is necessary with current clang-15 since
+          # older autoconf generate functions without prototype and -pedantic
+          # now implies strict-prototypes. Disabling the error but leaving the
+          # warning generates a lot of noise from use of ANYARGS in
+          # rb_define_method() and friends.
+          # See: https://github.com/llvm/llvm-project/commit/11da1b53d8cd3507959022cd790d5a7ad4573d94
+          - { name: c99,   env: { append_cc: '-std=c99   -Werror=pedantic -pedantic-errors -Wno-strict-prototypes' } }
+#         - { name: c11,   env: { append_cc: '-std=c11   -Werror=pedantic -pedantic-errors -Wno-strict-prototypes' } }
+#         - { name: c17,   env: { append_cc: '-std=c17   -Werror=pedantic -pedantic-errors -Wno-strict-prototypes' } }
+          - { name: c2x,   env: { append_cc: '-std=c2x   -Werror=pedantic -pedantic-errors -Wno-strict-prototypes' } }
+          - { name: c++98, env: { CXXFLAGS: '-std=c++98 -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' } }
+#         - { name: c++11, env: { CXXFLAGS: '-std=c++11 -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' } }
+#         - { name: c++14, env: { CXXFLAGS: '-std=c++14 -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' } }
+#         - { name: c++17, env: { CXXFLAGS: '-std=c++17 -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' } }
+          - { name: c++2a, env: { CXXFLAGS: '-std=c++2a -Werror=pedantic -pedantic-errors -Wno-c++11-long-long' } }
+
+          - { name: '-O0', env: { optflags: '-O0 -march=x86-64 -mtune=generic' } }
+#         - { name: '-O3', env: { optflags: '-O3 -march=x86-64 -mtune=generic' }, check: true }
+
+          - { name: gmp,                  env: { append_configure: '--with-gmp' } }
+          - { name: jemalloc,             env: { append_configure: '--with-jemalloc' } }
+          - { name: valgrind,             env: { append_configure: '--with-valgrind' } }
+          - { name: 'coroutine=ucontext', env: { append_configure: '--with-coroutine=ucontext' } }
+          - { name: 'coroutine=pthread',  env: { append_configure: '--with-coroutine=pthread' } }
+          - { name: disable-jit-support,  env: { append_configure: '--disable-jit-support' } }
+          - { name: disable-dln,          env: { append_configure: '--disable-dln' } }
+          - { name: enable-mkmf-verbose,  env: { append_configure: '--enable-mkmf-verbose' } }
+          - { name: disable-rubygems,     env: { append_configure: '--disable-rubygems' } }
+          - { name: RUBY_DEVEL,           env: { append_configure: '--enable-devel' } }
+
+          - { name: OPT_THREADED_CODE=1,            env: { cppflags: '-DOPT_THREADED_CODE=1' } }
+          - { name: OPT_THREADED_CODE=2,            env: { cppflags: '-DOPT_THREADED_CODE=2' } }
+          - { name: OPT_THREADED_CODE=3,            env: { cppflags: '-DOPT_THREADED_CODE=3' } }
+
+          - { name: NDEBUG,                         env: { cppflags: '-DNDEBUG' } }
+          - { name: RUBY_DEBUG,                     env: { cppflags: '-DRUBY_DEBUG' } }
+#         - { name: ARRAY_DEBUG,                    env: { cppflags: '-DARRAY_DEBUG' } }
+#         - { name: BIGNUM_DEBUG,                   env: { cppflags: '-DBIGNUM_DEBUG' } }
+#         - { name: CCAN_LIST_DEBUG,                env: { cppflags: '-DCCAN_LIST_DEBUG' } }
+#         - { name: CPDEBUG=-1,                     env: { cppflags: '-DCPDEBUG=-1' } }
+#         - { name: ENC_DEBUG,                      env: { cppflags: '-DENC_DEBUG' } }
+#         - { name: GC_DEBUG,                       env: { cppflags: '-DGC_DEBUG' } }
+#         - { name: HASH_DEBUG,                     env: { cppflags: '-DHASH_DEBUG' } }
+#         - { name: ID_TABLE_DEBUG,                 env: { cppflags: '-DID_TABLE_DEBUG' } }
+#         - { name: RGENGC_DEBUG=-1,                env: { cppflags: '-DRGENGC_DEBUG=-1' } }
+#         - { name: SYMBOL_DEBUG,                   env: { cppflags: '-DSYMBOL_DEBUG' } }
+
+#         - { name: RGENGC_CHECK_MODE,              env: { cppflags: '-DRGENGC_CHECK_MODE' } }
+#         - { name: TRANSIENT_HEAP_CHECK_MODE,      env: { cppflags: '-DTRANSIENT_HEAP_CHECK_MODE' } }
+#         - { name: VM_CHECK_MODE,                  env: { cppflags: '-DVM_CHECK_MODE' } }
+
+          - { name: USE_EMBED_CI=0,                 env: { cppflags: '-DUSE_EMBED_CI=0' } }
+          - name: USE_FLONUM=0,
+            env:
+              cppflags: '-DUSE_FLONUM=0'
+              # yjit requires FLONUM for the pointer tagging scheme
+              append_configure: '--disable-yjit'
+#         - { name: USE_GC_MALLOC_OBJ_INFO_DETAILS, env: { cppflags: '-DUSE_GC_MALLOC_OBJ_INFO_DETAILS' } }
+          - { name: USE_LAZY_LOAD,                  env: { cppflags: '-DUSE_LAZY_LOAD' } }
+#         - { name: USE_RINCGC=0,                   env: { cppflags: '-DUSE_RINCGC=0' } }
+#         - { name: USE_SYMBOL_GC=0,                env: { cppflags: '-DUSE_SYMBOL_GC=0' } }
+#         - { name: USE_THREAD_CACHE=0,             env: { cppflags: '-DUSE_THREAD_CACHE=0' } }
+#         - { name: USE_TRANSIENT_HEAP=0,           env: { cppflags: '-DUSE_TRANSIENT_HEAP=0' } }
+#         - { name: USE_RUBY_DEBUG_LOG=1,           env: { cppflags: '-DUSE_RUBY_DEBUG_LOG=1' } }
+          - { name: USE_RVARGC=0,                   env: { cppflags: '-DUSE_RVARGC=0' } }
+#         - { name: USE_RVARGC=1,                   env: { cppflags: '-DUSE_RVARGC=1' } }
+#         - { name: USE_DEBUG_COUNTER,              env: { cppflags: '-DUSE_DEBUG_COUNTER=1', RUBY_DEBUG_COUNTER_DISABLE: '1' } }
+
+          - { name: DEBUG_FIND_TIME_NUMGUESS,       env: { cppflags: '-DDEBUG_FIND_TIME_NUMGUESS' } }
+          - { name: DEBUG_INTEGER_PACK,             env: { cppflags: '-DDEBUG_INTEGER_PACK' } }
+#         - { name: ENABLE_PATH_CHECK,              env: { cppflags: '-DENABLE_PATH_CHECK' } }
+
+          - { name: GC_DEBUG_STRESS_TO_CLASS,       env: { cppflags: '-DGC_DEBUG_STRESS_TO_CLASS' } }
+#         - { name: GC_ENABLE_LAZY_SWEEP=0,         env: { cppflags: '-DGC_ENABLE_LAZY_SWEEP=0' } }
+#         - { name: GC_PROFILE_DETAIL_MEMOTY,       env: { cppflags: '-DGC_PROFILE_DETAIL_MEMOTY' } }
+#         - { name: GC_PROFILE_MORE_DETAIL,         env: { cppflags: '-DGC_PROFILE_MORE_DETAIL' } }
+
+#         - { name: CALC_EXACT_MALLOC_SIZE,         env: { cppflags: '-DCALC_EXACT_MALLOC_SIZE' } }
+#         - { name: MALLOC_ALLOCATED_SIZE_CHECK,    env: { cppflags: '-DMALLOC_ALLOCATED_SIZE_CHECK' } }
+
+#         - { name: IBF_ISEQ_ENABLE_LOCAL_BUFFER,   env: { cppflags: '-DIBF_ISEQ_ENABLE_LOCAL_BUFFER' } }
+
+#         - { name: RGENGC_ESTIMATE_OLDMALLOC,      env: { cppflags: '-DRGENGC_ESTIMATE_OLDMALLOC' } }
+#         - { name: RGENGC_FORCE_MAJOR_GC,          env: { cppflags: '-DRGENGC_FORCE_MAJOR_GC' } }
+#         - { name: RGENGC_OBJ_INFO,                env: { cppflags: '-DRGENGC_OBJ_INFO' } }
+#         - { name: RGENGC_OLD_NEWOBJ_CHECK,        env: { cppflags: '-DRGENGC_OLD_NEWOBJ_CHECK' } }
+#         - { name: RGENGC_PROFILE,                 env: { cppflags: '-DRGENGC_PROFILE' } }
+
+#         - { name: VM_DEBUG_BP_CHECK,              env: { cppflags: '-DVM_DEBUG_BP_CHECK' } }
+#         - { name: VM_DEBUG_VERIFY_METHOD_CACHE,   env: { cppflags: '-DVM_DEBUG_VERIFY_METHOD_CACHE' } }
+
+          - { name: MJIT_FORCE_ENABLE,              env: { cppflags: '-DMJIT_FORCE_ENABLE' } }
+          - { name: YJIT_FORCE_ENABLE,              env: { cppflags: '-DYJIT_FORCE_ENABLE' } }
+
+    name: ${{ matrix.entry.name }}
+    runs-on: ubuntu-latest
+    container:
+      image: ghcr.io/ruby/ruby-ci-image:${{ matrix.entry.container || matrix.entry.env.default_cc || 'clang-15' }}
+      options: --user root
+    if: ${{ !contains(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
+    env: ${{ matrix.entry.env || matrix.env }}
+    steps:
+      - run: id
+        working-directory:
+      - run: mkdir build
+        working-directory:
+      - name: setenv
+        run: |
+          echo "GNUMAKEFLAGS=-sj$((1 + $(nproc --all)))" >> $GITHUB_ENV
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          path: src
+      - uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+        with:
+          path: src/.downloaded-cache
+          key: downloaded-cache
+      - run: ./autogen.sh
+        working-directory: src
+      - name: Run configure
+        run: >
+          ../src/configure -C ${default_configure} ${append_configure}
+          --${{
+            matrix.entry.crosshost && 'host' || 'with-gcc'
+          }}=${{
+            matrix.entry.crosshost || '"${default_cc}${append_cc:+ $append_cc}"'
+          }}
+          --${{ matrix.entry.shared || 'enable' }}-shared
+      - run: make extract-extlibs
+      - run: make incs
+      - run: make showflags
+      - run: make
+      - run: make leaked-globals
+      - run: make test
+      - run: make install
+        if: ${{ matrix.entry.check }}
+      - run: make test-tool
+        if: ${{ matrix.entry.check }}
+      - run: make test-all TESTS='-- ruby -ext-'
+        if: ${{ matrix.entry.check }}
+      - run: make test-spec
+        env:
+          CHECK_LEAKS: true
+        if: ${{ matrix.entry.check }}
+      - run: make test-annocheck
+        if: ${{ matrix.entry.check && endsWith(matrix.entry.name, 'annocheck') }}
+
+      - uses: ruby/action-slack@0bd85c72233cdbb6a0fe01d37aaeff1d21b5fce1 # v3.2.1
+        with:
+          payload: |
+            {
+              "ci": "GitHub Actions",
+              "env": "${{ github.workflow }} / ${{ matrix.entry.name }}",
+              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
+              "commit": "${{ github.sha }}",
+              "branch": "${{ github.ref_name }}"
+            }
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() && github.event_name == 'push' }}
+
+defaults:
+  run:
+    working-directory: build
diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
new file mode 100644
index 0000000000..d8dc58b119
--- /dev/null
+++ b/.github/workflows/macos.yml
@@ -0,0 +1,113 @@
+name: macOS
+on:
+  push:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+  pull_request:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+  merge_group:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:
+  contents: read
+
+jobs:
+  make:
+    strategy:
+      matrix:
+        test_task: ["check"] # "test-bundler-parallel", "test-bundled-gems"
+        os:
+          - macos-13
+          - macos-14
+          - macos-15
+      fail-fast: false
+    env:
+      GITPULLOPTIONS: --no-tags origin ${{github.ref}}
+    runs-on: ${{ matrix.os }}
+    if: ${{ !contains(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
+    steps:
+      - run: mkdir build
+        working-directory:
+      - name: git config
+        run: |
+          git config --global advice.detachedHead 0
+          git config --global init.defaultBranch garbage
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          path: src
+      - uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+        with:
+          path: src/.downloaded-cache
+          key: downloaded-cache
+      - name: Install libraries
+        run: |
+          brew install gmp libffi openssl@1.1 zlib autoconf automake libtool readline bison
+        working-directory: src
+      - name: Set ENV
+        run: |
+          echo "MAKEFLAGS=-j$((1 + $(sysctl -n hw.activecpu)))" >> $GITHUB_ENV
+          echo "PATH="/usr/local/opt/bison/bin:/opt/homebrew/opt/bison/bin:$PATH"" >> $GITHUB_ENV
+      - run: ./autogen.sh
+        working-directory: src
+      - name: Run configure
+        run: ../src/configure -C --disable-install-doc --with-openssl-dir=$(brew --prefix openssl@1.1) --with-readline-dir=$(brew --prefix readline)
+      - run: make incs
+      - run: make prepare-gems
+        if: ${{ matrix.test_task == 'test-bundled-gems' }}
+      - run: make
+      - run: make leaked-globals
+        if: ${{ matrix.test_task == 'check' }}
+      - name: make ${{ matrix.test_task }}
+        run: |
+          make -s ${{ matrix.test_task }} ${TESTS:+TESTS=`echo "$TESTS" | sed 's| |$$/ -n!/|g;s|^|-n!/|;s|$|$$/|'`}
+        timeout-minutes: 40
+        env:
+          RUBY_TESTOPTS: "-q --tty=no"
+          TESTS: ${{ matrix.test_task == 'check' && matrix.skipped_tests || '' }}
+          TEST_BUNDLED_GEMS_ALLOW_FAILURES: ""
+          PRECHECK_BUNDLED_GEMS: "no"
+      - name: make skipped tests
+        run: |
+          make -s test-all TESTS=`echo "$TESTS" | sed 's| |$$/ -n/|g;s|^|-n/|;s|$|$$/|'`
+        env:
+          GNUMAKEFLAGS: ""
+          RUBY_TESTOPTS: "-v --tty=no"
+          TESTS: ${{ matrix.skipped_tests }}
+          PRECHECK_BUNDLED_GEMS: "no"
+        if: ${{ matrix.test_task == 'check' && matrix.skipped_tests != '' }}
+        continue-on-error: ${{ matrix.continue-on-skipped_tests || false }}
+      - uses: ruby/action-slack@0bd85c72233cdbb6a0fe01d37aaeff1d21b5fce1 # v3.2.1
+        with:
+          payload: |
+            {
+              "ci": "GitHub Actions",
+              "env": "${{ matrix.os }} / ${{ matrix.test_task }}${{ matrix.configure }}",
+              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
+              "commit": "${{ github.sha }}",
+              "branch": "${{ github.ref_name }}"
+            }
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() && github.event_name == 'push' }}
+
+defaults:
+  run:
+    working-directory: build
diff --git a/.github/workflows/mingw.yml b/.github/workflows/mingw.yml
new file mode 100644
index 0000000000..0df917d3d8
--- /dev/null
+++ b/.github/workflows/mingw.yml
@@ -0,0 +1,179 @@
+name: MinGW
+on:
+  push:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+  pull_request:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+  merge_group:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:
+  contents: read
+
+# Notes:
+# Actions console encoding causes issues, see test-all & test-spec steps
+#
+jobs:
+  make:
+    runs-on: windows-2022
+    name: ${{ github.workflow }} (${{ matrix.msystem }})
+    env:
+      MSYSTEM: ${{ matrix.msystem }}
+      MSYS2_ARCH: x86_64
+      CHOST: "x86_64-w64-mingw32"
+      CFLAGS:   "-march=x86-64 -mtune=generic -O3 -pipe"
+      CXXFLAGS: "-march=x86-64 -mtune=generic -O3 -pipe"
+      CPPFLAGS: "-D_FORTIFY_SOURCE=2 -D__USE_MINGW_ANSI_STDIO=1 -DFD_SETSIZE=2048"
+      LDFLAGS:  "-pipe"
+      UPDATE_UNICODE: "UNICODE_FILES=. UNICODE_PROPERTY_FILES=. UNICODE_AUXILIARY_FILES=. UNICODE_EMOJI_FILES=."
+      GITPULLOPTIONS: --no-tags origin ${{github.ref}}
+    strategy:
+      matrix:
+        include:
+          # To mitigate flakiness of MinGW CI, we test only one runtime that newer MSYS2 uses.
+          - msystem: "UCRT64"
+            base_ruby: head
+            test_task: "check"
+            test-all-opts: "--name=!/TestObjSpace#test_reachable_objects_during_iteration/"
+      fail-fast: false
+    if: ${{ !contains(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
+    steps:
+      - run: mkdir build
+        working-directory:
+      - name: git config
+        run: |
+          git config --global core.autocrlf false
+          git config --global core.eol lf
+          git config --global advice.detachedHead 0
+          git config --global init.defaultBranch garbage
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          path: src
+      - uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+        with:
+          path: src/.downloaded-cache
+          key: downloaded-cache
+      - name: Set up Ruby & MSYS2
+        uses: ruby/setup-ruby@13e7a03dc3ac6c3798f4570bfead2aed4d96abfb # v1.244.0
+        with:
+          ruby-version: ${{ matrix.base_ruby }}
+      - name: set env
+        run: |
+          echo "GNUMAKEFLAGS=-j$((2 * NUMBER_OF_PROCESSORS))" >> $GITHUB_ENV
+
+      - name: where check
+        run: |
+          # show where
+          mv /c/Windows/System32/libcrypto-1_1-x64.dll /c/Windows/System32/libcrypto-1_1-x64.dll_
+          mv /c/Windows/System32/libssl-1_1-x64.dll    /c/Windows/System32/libssl-1_1-x64.dll_
+          result=true
+          for e in gcc.exe ragel.exe make.exe bison.exe libcrypto-1_1-x64.dll libssl-1_1-x64.dll; do
+            echo '##['group']'$'\033[93m'$e$'\033[m'
+            where $e || result=false
+            echo '##['endgroup']'
+          done
+          $result
+
+      - name: version check
+        run: |
+          # show version
+          result=true
+          for e in gcc ragel make bison "openssl version"; do
+            case "$e" in *" "*) ;; *) e="$e --version";; esac
+            echo '##['group']'$'\033[93m'$e$'\033[m'
+            $e || result=false
+            echo '##['endgroup']'
+          done
+          $result
+
+      - name: autogen
+        run: |
+          ./autogen.sh
+        working-directory: src
+
+      - name: configure
+        run: >
+          ../src/configure --disable-install-doc --prefix=/.
+          --build=$CHOST --host=$CHOST --target=$CHOST
+
+      - name: update
+        run: |
+          make incs
+
+      - name: download gems
+        run: |
+          make update-gems
+
+      - name: make all
+        timeout-minutes: 30
+        run: |
+          make
+
+      - run: make leaked-globals
+
+      - name: make install
+        run: |
+          make DESTDIR=../install install-nodoc
+
+      - name: test
+        timeout-minutes: 5
+        run: |
+          make test
+        if: ${{matrix.test_task == 'check' || matrix.test_task == 'test'}}
+
+      - name: test-all
+        timeout-minutes: 45
+        run: |
+          # Actions uses UTF8, causes test failures, similar to normal OS setup
+          chcp.com 437
+          make ${{ StartsWith(matrix.test_task, 'test/') && matrix.test_task || 'test-all' }}
+        env:
+          RUBY_TESTOPTS: >-
+            --retry --job-status=normal --show-skip --timeout-scale=1.5
+            ${{ matrix.test-all-opts }}
+          BUNDLER_VERSION:
+        if: ${{matrix.test_task == 'check' || matrix.test_task == 'test-all' || StartsWith(matrix.test_task, 'test/')}}
+
+      - name: test-spec
+        timeout-minutes: 10
+        run: |
+          make ${{ StartsWith(matrix.test_task, 'spec/') && matrix.test_task || 'test-spec' }}
+        if: ${{matrix.test_task == 'check' || matrix.test_task == 'test-spec' || StartsWith(matrix.test_task, 'spec/')}}
+
+      - uses: ruby/action-slack@0bd85c72233cdbb6a0fe01d37aaeff1d21b5fce1 # v3.2.1
+        with:
+          payload: |
+            {
+              "ci": "GitHub Actions",
+              "env": "${{ github.workflow }} ${{ matrix.msystem }} / ${{ matrix.test_task }}",
+              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
+              "commit": "${{ github.sha }}",
+              "branch": "${{ github.ref_name }}"
+            }
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() && github.event_name == 'push' }}
+
+defaults:
+  run:
+    working-directory: build
+    shell: sh
diff --git a/.github/workflows/mjit-bindgen.yml b/.github/workflows/mjit-bindgen.yml
new file mode 100644
index 0000000000..26f8a1b2aa
--- /dev/null
+++ b/.github/workflows/mjit-bindgen.yml
@@ -0,0 +1,104 @@
+name: MJIT bindgen
+on:
+  push:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+  pull_request:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+  merge_group:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:
+  contents: read
+
+jobs:
+  make:
+    strategy:
+      matrix:
+        include:
+          - task: mjit-bindgen
+      fail-fast: false
+    runs-on: ubuntu-22.04
+    if: ${{ !contains(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
+    steps:
+      - run: mkdir build
+        working-directory:
+      - name: Set ENV
+        run: |
+          echo "GNUMAKEFLAGS=-j$((1 + $(nproc --all)))" >> $GITHUB_ENV
+      - name: Install libraries
+        run: |
+          set -x
+          sudo apt-get update -q || :
+          sudo apt-get install --no-install-recommends -q -y \
+          build-essential \
+          libssl-dev libyaml-dev libreadline6-dev \
+          zlib1g-dev libncurses5-dev libffi-dev \
+          libclang1-14 \
+          bison autoconf
+          sudo apt-get install -q -y pkg-config || :
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@13e7a03dc3ac6c3798f4570bfead2aed4d96abfb # v1.244.0
+        with:
+          ruby-version: '3.1'
+      - name: git config
+        run: |
+          git config --global advice.detachedHead 0
+          git config --global init.defaultBranch garbage
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          path: src
+      - uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+        with:
+          path: src/.downloaded-cache
+          key: downloaded-cache
+      - name: Fixed world writable dirs
+        run: |
+          chmod -v go-w $HOME $HOME/.config
+          sudo chmod -R go-w /usr/share
+          sudo bash -c 'IFS=:; for d in '"$PATH"'; do chmod -v go-w $d; done' || :
+      - run: ./autogen.sh
+        working-directory: src
+      - name: Run configure
+        run: ../src/configure -C --disable-install-doc --prefix=$(pwd)/install --enable-yjit=dev_nodebug
+      - run: make incs
+      - run: make
+      - run: make install
+      - run: make ${{ matrix.task }}
+      - run: git diff --exit-code
+        working-directory: src
+      - uses: ruby/action-slack@0bd85c72233cdbb6a0fe01d37aaeff1d21b5fce1 # v3.2.1
+        with:
+          payload: |
+            {
+              "ci": "GitHub Actions",
+              "env": "${{ matrix.os }} / ${{ matrix.test_task }}${{ matrix.configure }}",
+              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
+              "commit": "${{ github.sha }}",
+              "branch": "${{ github.ref_name }}"
+            }
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() && github.event_name == 'push' }}
+
+defaults:
+  run:
+    working-directory: build
diff --git a/.github/workflows/mjit.yml b/.github/workflows/mjit.yml
new file mode 100644
index 0000000000..6f7181489a
--- /dev/null
+++ b/.github/workflows/mjit.yml
@@ -0,0 +1,113 @@
+name: MJIT
+on:
+  push:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+  pull_request:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+      - '**.[1-8]'
+      - '**.ronn'
+  merge_group:
+    paths-ignore:
+      - 'doc/**'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+      - '**.[1-8]'
+      - '**.ronn'
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:
+  contents: read
+
+jobs:
+  make:
+    strategy:
+      matrix:
+        test_task: [check] # to make job names consistent
+        mjit_opts: [--mjit-wait]
+      fail-fast: false
+    runs-on: ubuntu-latest
+    if: ${{ !contains(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
+    env:
+      TESTOPTS: '-q --tty=no'
+      RUN_OPTS: '--disable-gems ${{ matrix.mjit_opts }} --mjit-debug=-ggdb3'
+      GITPULLOPTIONS: --no-tags origin ${{github.ref}}
+    steps:
+      - run: mkdir build
+        working-directory:
+      - name: Install libraries
+        run: |
+          set -x
+          sudo apt-get update -q || :
+          sudo apt-get install --no-install-recommends -q -y build-essential libssl-dev libyaml-dev libreadline6-dev zlib1g-dev libncurses5-dev libffi-dev bison autoconf ruby
+      - name: git config
+        run: |
+          git config --global advice.detachedHead 0
+          git config --global init.defaultBranch garbage
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          path: src
+      - uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+        with:
+          path: src/.downloaded-cache
+          key: downloaded-cache
+      - name: Fixed world writable dirs
+        run: |
+          chmod -v go-w $HOME $HOME/.config
+          sudo chmod -R go-w /usr/share
+          sudo bash -c 'IFS=:; for d in '"$PATH"'; do chmod -v go-w $d; done' || :
+      - name: Set ENV
+        run: |
+          echo "GNUMAKEFLAGS=-j$((1 + $(nproc --all)))" >> $GITHUB_ENV
+      - run: ./autogen.sh
+        working-directory: src
+      - name: Run configure
+        run: ../src/configure -C --disable-install-doc cppflags=-DVM_CHECK_MODE
+      - run: make incs
+      - run: make
+      - run: sudo make -s install
+      - name: Run test
+        run: |
+          unset GNUMAKEFLAGS
+          make -s test RUN_OPTS="$RUN_OPTS"
+        timeout-minutes: 60
+      # - name: Run test-all
+      #   run: |
+      #     ulimit -c unlimited
+      #     make -s test-all RUN_OPTS="$RUN_OPTS"
+      #   timeout-minutes: 60
+      - name: Run test-spec
+        run: |
+          unset GNUMAKEFLAGS
+          make -s test-spec RUN_OPTS="$RUN_OPTS"
+        timeout-minutes: 60
+      - uses: ruby/action-slack@0bd85c72233cdbb6a0fe01d37aaeff1d21b5fce1 # v3.2.1
+        with:
+          payload: |
+            {
+              "ci": "GitHub Actions",
+              "env": "${{ github.workflow }} / ${{ matrix.test_task }} ${{ matrix.mjit_opts }}",
+              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
+              "commit": "${{ github.sha }}",
+              "branch": "${{ github.ref_name }}"
+            }
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() && github.event_name == 'push' }}
+
+defaults:
+  run:
+    working-directory: build
diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
new file mode 100644
index 0000000000..5d4474d978
--- /dev/null
+++ b/.github/workflows/publish.yml
@@ -0,0 +1,18 @@
+name: Start release workflow
+on:
+  push:
+    tags:
+      - '*'
+
+jobs:
+  notify:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Build release package
+        run: |
+          curl -L -X POST \
+            -H "Authorization: Bearer ${{ secrets.MATZBOT_GITHUB_WORKFLOW_TOKEN }}" \
+            -H "Accept: application/vnd.github+json" \
+            -H "X-GitHub-Api-Version: 2022-11-28" \
+            https://api.github.com/repos/ruby/actions/dispatches \
+            -d '{"event_type": "${{ github.ref }}"}'
diff --git a/.github/workflows/scorecards.yml b/.github/workflows/scorecards.yml
new file mode 100644
index 0000000000..c12a95362d
--- /dev/null
+++ b/.github/workflows/scorecards.yml
@@ -0,0 +1,72 @@
+# This workflow uses actions that are not certified by GitHub. They are provided
+# by a third-party and are governed by separate terms of service, privacy
+# policy, and support documentation.
+
+name: Scorecards supply-chain security
+on:
+  # For Branch-Protection check. Only the default branch is supported. See
+  # https://github.com/ossf/scorecard/blob/main/docs/checks.md#branch-protection
+  branch_protection_rule:
+  # To guarantee Maintained check is occasionally updated. See
+  # https://github.com/ossf/scorecard/blob/main/docs/checks.md#maintained
+  schedule:
+    - cron: '22 4 * * 2'
+  push:
+    branches: [ "master" ]
+
+# Declare default permissions as read only.
+permissions: read-all
+
+jobs:
+  analysis:
+    name: Scorecards analysis
+    runs-on: ubuntu-latest
+    permissions:
+      # Needed to upload the results to code-scanning dashboard.
+      security-events: write
+      # Needed to publish results and get a badge (see publish_results below).
+      id-token: write
+      # Uncomment the permissions below if installing in a private repository.
+      # contents: read
+      # actions: read
+
+    steps:
+      - name: "Checkout code"
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          persist-credentials: false
+
+      - name: "Run analysis"
+        uses: ossf/scorecard-action@ea651e62978af7915d09fe2e282747c798bf2dab # v2.4.1
+        with:
+          results_file: results.sarif
+          results_format: sarif
+          # (Optional) Read-only PAT token. Uncomment the `repo_token` line below if:
+          # - you want to enable the Branch-Protection check on a *public* repository, or
+          # - you are installing Scorecards on a *private* repository
+          # To create the PAT, follow the steps in https://github.com/ossf/scorecard-action#authentication-with-pat.
+          repo_token: ${{ secrets.SCORECARD_READ_TOKEN }}
+
+          # Public repositories:
+          #   - Publish results to OpenSSF REST API for easy access by consumers
+          #   - Allows the repository to include the Scorecard badge.
+          #   - See https://github.com/ossf/scorecard-action#publishing-results.
+          # For private repositories:
+          #   - `publish_results` will always be set to `false`, regardless
+          #     of the value entered here.
+          publish_results: true
+
+      # Upload the results as artifacts (optional). Commenting out will disable uploads of run results in SARIF
+      # format to the repository Actions tab.
+      - name: "Upload artifact"
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
+        with:
+          name: SARIF file
+          path: results.sarif
+          retention-days: 5
+
+      # Upload the results to GitHub's code scanning dashboard.
+      - name: "Upload to code-scanning"
+        uses: github/codeql-action/upload-sarif@959cbb7472c4d4ad70cdfe6f4976053fe48ab394 # v2.1.27
+        with:
+          sarif_file: results.sarif
diff --git a/.github/workflows/spec_guards.yml b/.github/workflows/spec_guards.yml
new file mode 100644
index 0000000000..4521195a2b
--- /dev/null
+++ b/.github/workflows/spec_guards.yml
@@ -0,0 +1,71 @@
+name: Rubyspec Version Guards Check
+
+on:
+  push:
+    paths:
+      - 'spec/**'
+      - '!spec/*.md'
+  pull_request:
+    paths:
+      - 'spec/**'
+      - '!spec/*.md'
+  merge_group:
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:
+  contents: read
+
+jobs:
+  rubyspec:
+    name: Rubyspec
+
+    runs-on: ubuntu-22.04
+
+    if: >-
+      ${{!(false
+      || contains(github.event.head_commit.message, '[DOC]')
+      || contains(github.event.head_commit.message, 'Document')
+      || contains(github.event.pull_request.title, '[DOC]')
+      || contains(github.event.pull_request.title, 'Document')
+      || contains(github.event.pull_request.labels.*.name, 'Document')
+      || (github.event_name == 'push' && github.actor == 'dependabot[bot]')
+      )}}
+
+    strategy:
+      matrix:
+        # Specs from ruby/spec should still run on all supported Ruby versions.
+        # This also ensures the needed ruby_version_is guards are there, see spec/README.md.
+        ruby:
+          - ruby-3.1
+          - ruby-3.2
+
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+
+      - uses: ruby/setup-ruby@13e7a03dc3ac6c3798f4570bfead2aed4d96abfb # v1.244.0
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          bundler: none
+
+      - run: gem install webrick
+
+      - run: ruby ../mspec/bin/mspec
+        working-directory: spec/ruby
+        env:
+          CHECK_LEAKS: true
+      - uses: ruby/action-slack@0bd85c72233cdbb6a0fe01d37aaeff1d21b5fce1 # v3.2.1
+        with:
+          payload: |
+            {
+              "ci": "GitHub Actions",
+              "env": "${{ github.workflow }} / rubyspec @ ${{ matrix.ruby }}",
+              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
+              "commit": "${{ github.sha }}",
+              "branch": "${{ github.ref_name }}"
+            }
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() }}
diff --git a/.github/workflows/ubuntu.yml b/.github/workflows/ubuntu.yml
new file mode 100644
index 0000000000..4fbca1170e
--- /dev/null
+++ b/.github/workflows/ubuntu.yml
@@ -0,0 +1,146 @@
+name: Ubuntu
+on:
+  push:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+  pull_request:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+  merge_group:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:
+  contents: read
+
+jobs:
+  make:
+    strategy:
+      matrix:
+        # main variables included in the job name
+        test_task: [check]
+        configure: [cppflags=-DRUBY_DEBUG] # default to use more assertions
+        arch: ['']
+        # specify all jobs with `include` to avoid testing duplicated things
+        include:
+          - test_task: check
+          - test_task: check
+            arch: i686
+            configure: '' # test without -DRUBY_DEBUG as well
+          - test_task: check
+            configure: "--enable-shared --enable-load-relative"
+          - test_task: test-all TESTS=--repeat-count=2
+          - test_task: test-bundler-parallel
+          - test_task: test-bundled-gems
+      fail-fast: false
+    env:
+      GITPULLOPTIONS: --no-tags origin ${{github.ref}}
+      RUBY_DEBUG: ci
+      SETARCH: ${{ matrix.arch && format('setarch {0}', matrix.arch) }}
+    runs-on: ubuntu-22.04
+    if: ${{ !contains(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
+    steps:
+      - run: mkdir build
+        working-directory:
+      - name: Set ENV
+        run: |
+          echo "GNUMAKEFLAGS=-j$((1 + $(nproc --all)))" >> $GITHUB_ENV
+      - name: Install libraries
+        env:
+          arch: ${{matrix.arch}}
+        run: |
+          set -x
+          arch=${arch:+:${arch/i[3-6]86/i386}}
+          ${arch:+sudo dpkg --add-architecture ${arch#:}}
+          sudo apt-get update -q || :
+          sudo apt-get install --no-install-recommends -q -y \
+          ${arch:+cross}build-essential${arch/:/-} \
+          libssl-dev${arch} libyaml-dev${arch} libreadline6-dev${arch} \
+          zlib1g-dev${arch} libncurses5-dev${arch} libffi-dev${arch} \
+          bison autoconf ruby
+          sudo apt-get install -q -y pkg-config${arch} || :
+      - name: git config
+        run: |
+          git config --global advice.detachedHead 0
+          git config --global init.defaultBranch garbage
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          path: src
+      - uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+        with:
+          path: src/.downloaded-cache
+          key: downloaded-cache
+      - name: Fixed world writable dirs
+        run: |
+          chmod -v go-w $HOME $HOME/.config
+          sudo chmod -R go-w /usr/share
+          sudo bash -c 'IFS=:; for d in '"$PATH"'; do chmod -v go-w $d; done' || :
+      - run: ./autogen.sh
+        working-directory: src
+      - name: Run configure
+        env:
+          arch: ${{matrix.arch}}
+        run: >-
+          $SETARCH ../src/configure -C --disable-install-doc ${{ matrix.configure }}
+          ${arch:+--target=$arch-$OSTYPE --host=$arch-$OSTYPE}
+      - run: $SETARCH make incs
+      - run: $SETARCH make prepare-gems
+        if: ${{ matrix.test_task == 'test-bundled-gems' }}
+      - run: $SETARCH make
+      - run: $SETARCH make leaked-globals
+        if: ${{ matrix.test_task == 'check' }}
+      - name: Create dummy files in build dir
+        run: |
+          $SETARCH ./miniruby -e '(("a".."z").to_a+("A".."Z").to_a+("0".."9").to_a+%w[foo bar test zzz]).each{|basename|File.write("#{basename}.rb", "raise %(do not load #{basename}.rb)")}'
+        if: ${{ matrix.test_task == 'check' }}
+      - name: make ${{ matrix.test_task }}
+        run: |
+          $SETARCH make -s ${{ matrix.test_task }} ${TESTS:+TESTS=`echo "$TESTS" | sed 's| |$$/ -n!/|g;s|^|-n!/|;s|$|$$/|'`}
+        timeout-minutes: 40
+        env:
+          RUBY_TESTOPTS: "-q --tty=no"
+          TESTS: ${{ matrix.test_task == 'check' && matrix.skipped_tests || '' }}
+          TEST_BUNDLED_GEMS_ALLOW_FAILURES: ""
+          PRECHECK_BUNDLED_GEMS: "no"
+      - name: make skipped tests
+        run: |
+          $SETARCH make -s test-all TESTS=`echo "$TESTS" | sed 's| |$$/ -n/|g;s|^|-n/|;s|$|$$/|'`
+        env:
+          GNUMAKEFLAGS: ""
+          RUBY_TESTOPTS: "-v --tty=no"
+          TESTS: ${{ matrix.skipped_tests }}
+        if: ${{ matrix.test_task == 'check' && matrix.skipped_tests != '' }}
+        continue-on-error: ${{ matrix.continue-on-skipped_tests || false }}
+      - uses: ruby/action-slack@0bd85c72233cdbb6a0fe01d37aaeff1d21b5fce1 # v3.2.1
+        with:
+          payload: |
+            {
+              "ci": "GitHub Actions",
+              "env": "${{ github.workflow }} / ${{ matrix.test_task }} ${{ matrix.configure }}${{ matrix.arch }}",
+              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
+              "commit": "${{ github.sha }}",
+              "branch": "${{ github.ref_name }}"
+            }
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() && github.event_name == 'push' }}
+
+defaults:
+  run:
+    working-directory: build
diff --git a/.github/workflows/wasm.yml b/.github/workflows/wasm.yml
new file mode 100644
index 0000000000..27920b5821
--- /dev/null
+++ b/.github/workflows/wasm.yml
@@ -0,0 +1,146 @@
+name: WebAssembly
+on:
+  push:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+  pull_request:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+  merge_group:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:  # added using https://github.com/step-security/secure-workflows
+  contents: read
+
+jobs:
+  make:
+    strategy:
+      matrix:
+        entry:
+#         # wasmtime can't compile non-optimized Asyncified binary due to locals explosion
+#         - { name: O0-debuginfo, optflags: "-O0", debugflags: "-g", wasmoptflags: "-O1" }
+#         - { name: O1,           optflags: "-O1", debugflags: ""  , wasmoptflags: "-O1" }
+          - { name: O2,           optflags: "-O2", debugflags: ""  , wasmoptflags: "-O2" }
+#         - { name: O3,           optflags: "-O3", debugflags: ""  , wasmoptflags: "-O3" }
+#         # -O4 is equivalent to -O3 in clang, but it's different in wasm-opt
+#         - { name: O4,           optflags: "-O3", debugflags: ""  , wasmoptflags: "-O4" }
+#         - { name: Oz,           optflags: "-Oz", debugflags: ""  , wasmoptflags: "-Oz" }
+      fail-fast: false
+    env:
+      RUBY_TESTOPTS: '-q --tty=no'
+      GITPULLOPTIONS: --no-tags origin ${{github.ref}}
+      WASI_SDK_VERSION_MAJOR: 14
+      WASI_SDK_VERSION_MINOR: 0
+      BINARYEN_VERSION: 109
+      WASMTIME_VERSION: v0.33.0
+    runs-on: ubuntu-22.04
+    if: ${{ !contains(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
+    steps:
+      - run: mkdir build
+        working-directory:
+      - name: git config
+        run: |
+          git config --global advice.detachedHead 0
+          git config --global init.defaultBranch garbage
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          path: src
+      - name: Install libraries
+        run: |
+          set -ex
+          sudo apt-get update -q || :
+          sudo apt-get install --no-install-recommends -q -y ruby bison make autoconf git wget
+
+          wasi_sdk_deb="wasi-sdk_${WASI_SDK_VERSION_MAJOR}.${WASI_SDK_VERSION_MINOR}_amd64.deb"
+          wget "https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-${WASI_SDK_VERSION_MAJOR}/${wasi_sdk_deb}"
+          sudo dpkg -i "$wasi_sdk_deb"
+          rm -f "$wasi_sdk_deb"
+
+          mkdir build-sdk
+          pushd build-sdk
+
+          wasmtime_url="https://github.com/bytecodealliance/wasmtime/releases/download/${WASMTIME_VERSION}/wasmtime-${WASMTIME_VERSION}-x86_64-linux.tar.xz"
+          wget -O - "$wasmtime_url" | tar xJf -
+          sudo ln -fs "$PWD/wasmtime-${WASMTIME_VERSION}-x86_64-linux/wasmtime" /usr/local/bin/wasmtime
+
+          binaryen_tarball="binaryen-version_${BINARYEN_VERSION}-x86_64-linux.tar.gz"
+          binaryen_url="https://github.com/WebAssembly/binaryen/releases/download/version_${BINARYEN_VERSION}/${binaryen_tarball}"
+          wget -O - "$binaryen_url" | tar xfz -
+          sudo ln -fs "$PWD/binaryen-version_${BINARYEN_VERSION}/bin/wasm-opt" /usr/local/bin/wasm-opt
+        working-directory: src
+      - name: Set ENV
+        run: |
+          echo "MAKEFLAGS=-j$((1 + $(sysctl -n hw.activecpu)))" >> $GITHUB_ENV
+          echo "WASI_SDK_PATH=/opt/wasi-sdk" >> $GITHUB_ENV
+      - run: ./autogen.sh
+        working-directory: src
+
+      - uses: ruby/setup-ruby@13e7a03dc3ac6c3798f4570bfead2aed4d96abfb # v1.244.0
+        with:
+          ruby-version: '3.0'
+          bundler: none
+
+      - name: Download config.guess with wasi version
+        run: |
+          rm tool/config.guess tool/config.sub
+          ruby tool/downloader.rb -d tool -e gnu config.guess config.sub
+        working-directory: src
+
+      - name: Run configure
+        run: |
+          ../src/configure \
+            --host wasm32-unknown-wasi \
+            --with-static-linked-ext \
+            LDFLAGS=" \
+              -Xlinker --stack-first \
+              -Xlinker -z -Xlinker stack-size=16777216 \
+            " \
+            optflags="${{ matrix.entry.optflags }}" \
+            debugflags="${{ matrix.entry.debugflags }}" \
+            wasmoptflags="${{ matrix.entry.wasmoptflags }} ${{ matrix.entry.debugflags }}"
+
+      # miniruby may not be built when cross-compling
+      - run: make mini ruby
+      - name: Run basictest
+        run: wasmtime run ./../build/miniruby --mapdir /::./ -- basictest/test.rb
+        working-directory: src
+      - name: Run bootstraptest (no thread)
+        run: |
+          NO_THREAD_TESTS="$(grep -L Thread -R ./bootstraptest | awk -F/ '{ print $NF }' | uniq | sed -n 's/test_\(.*\).rb/\1/p' | paste -s -d, -)"
+          ruby ./bootstraptest/runner.rb --ruby="$(which wasmtime) run $PWD/../build/ruby --mapdir /::./ -- " --verbose "--sets=$NO_THREAD_TESTS"
+        working-directory: src
+
+      - uses: ruby/action-slack@0bd85c72233cdbb6a0fe01d37aaeff1d21b5fce1 # v3.2.1
+        with:
+          payload: |
+            {
+              "ci": "GitHub Actions",
+              "env": "${{ github.workflow }} / ${{ matrix.name }}",
+              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
+              "commit": "${{ github.sha }}",
+              "branch": "${{ github.ref_name }}"
+            }
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() && github.event_name == 'push' }}
+
+defaults:
+  run:
+    working-directory: build
diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
new file mode 100644
index 0000000000..c2bd4881c2
--- /dev/null
+++ b/.github/workflows/windows.yml
@@ -0,0 +1,149 @@
+name: Windows
+on:
+  push:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+  pull_request:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+  merge_group:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:
+  contents: read
+
+jobs:
+  make:
+    strategy:
+      matrix:
+        include:
+          - vs: 2022
+            vcvers: -vcvars_ver=14.2
+      fail-fast: false
+    runs-on: windows-${{ matrix.vs }}
+    if: ${{ !contains(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
+    name: VisualStudio ${{ matrix.vs }}
+    env:
+      GITPULLOPTIONS: --no-tags origin ${{github.ref}}
+      PATCH: C:\msys64\usr\bin\patch.exe
+      OS_VER: windows-${{ matrix.vs }}
+    steps:
+      - run: md build
+        working-directory:
+      - uses: msys2/setup-msys2@61f9e5e925871ba6c9e3e8da24ede83ea27fa91f # v2.27.0
+        id: setup-msys2
+        with:
+          update: true
+          install: bison patch
+      - name: patch path
+        shell: msys2 {0}
+        run: echo PATCH=$(cygpath -wa $(command -v patch)) >> $GITHUB_ENV
+        if: ${{ steps.setup-msys2.outcome == 'success' }}
+      - uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+        with:
+          path: C:\vcpkg\installed
+          key: ${{ runner.os }}-vcpkg-installed-windows-${{ matrix.vs }}-${{ github.sha }}
+          restore-keys: |
+            ${{ runner.os }}-vcpkg-installed-windows-${{ matrix.vs }}-
+            ${{ runner.os }}-vcpkg-installed-windows-
+      - name: Install libraries with vcpkg
+        run: |
+          iex "& {$(irm get.scoop.sh)} -RunAsAdmin"
+          Join-Path (Resolve-Path ~).Path "scoop\shims" >> $Env:GITHUB_PATH
+          scoop install cmake@3.31.6
+          vcpkg --triplet x64-windows install libffi libyaml openssl readline zlib
+        shell:
+          pwsh
+      - name: git config
+        run: |
+          git config --global core.autocrlf false
+          git config --global core.eol lf
+          git config --global advice.detachedHead 0
+          git config --global init.defaultBranch garbage
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          path: src
+      - uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+        with:
+          path: src/.downloaded-cache
+          key: downloaded-cache
+      - name: setup env
+        # %TEMP% is inconsistent with %TMP% and test-all expects they are consistent.
+        # https://github.com/actions/virtual-environments/issues/712#issuecomment-613004302
+        # msys2/setup-msys2 installs MSYS2 to D:/a/_temp/msys64/usr/bin
+        run: |
+          set Path=D:/a/_temp/msys64/usr/bin;%Path%
+          if not "%VCVARS%" == "" goto :vcset
+            set VCVARS="C:\Program Files (x86)\Microsoft Visual Studio\${{ matrix.vs }}\Enterprise\VC\Auxiliary\Build\vcvars64.bat"
+            if not exist %VCVARS% set VCVARS="C:\Program Files\Microsoft Visual Studio\${{ matrix.vs }}\Enterprise\VC\Auxiliary\Build\vcvars64.bat"
+          :vcset
+          set | C:\msys64\usr\bin\sort > old.env
+          call %VCVARS% ${{ matrix.vcvers || ''}}
+          set TMP=%USERPROFILE%\AppData\Local\Temp
+          set TEMP=%USERPROFILE%\AppData\Local\Temp
+          set /a TEST_JOBS=(15 * %NUMBER_OF_PROCESSORS% / 10) > nul
+          set | C:\msys64\usr\bin\sort > new.env
+          C:\msys64\usr\bin\comm -13 old.env new.env >> %GITHUB_ENV%
+          del *.env
+      - name: compiler version
+        run: cl
+      - name: link libraries
+        run: |
+          for %%I in (C:\vcpkg\installed\x64-windows\bin\*.dll) do (
+            if not %%~nI == readline mklink %%~nxI %%I
+          )
+          for %%I in (libcrypto-1_1-x64 libssl-1_1-x64) do (
+            ren c:\Windows\System32\%%I.dll %%I.dll_
+          )
+      - name: Configure
+        run: >-
+          ../src/win32/configure.bat --disable-install-doc
+          --with-opt-dir=C:/vcpkg/installed/x64-windows
+      - run: nmake incs
+      - run: nmake extract-extlibs
+      - run: nmake
+        env:
+          YACC: bison.exe
+      - run: nmake test
+        timeout-minutes: 5
+      - run: nmake test-spec
+        timeout-minutes: 10
+      - run: nmake test-all
+        env:
+          RUBY_TESTOPTS: -j${{env.TEST_JOBS}} --job-status=normal
+        timeout-minutes: 60
+      - uses: ruby/action-slack@0bd85c72233cdbb6a0fe01d37aaeff1d21b5fce1 # v3.2.1
+        with:
+          payload: |
+            {
+              "ci": "GitHub Actions",
+              "env": "VS${{ matrix.vs }} / ${{ matrix.test_task || 'check' }}",
+              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
+              "commit": "${{ github.sha }}",
+              "branch": "${{ github.ref_name }}"
+            }
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() && github.event_name == 'push' }}
+
+defaults:
+  run:
+    working-directory: build
+    shell: cmd
diff --git a/.github/workflows/yjit-ubuntu.yml b/.github/workflows/yjit-ubuntu.yml
new file mode 100644
index 0000000000..0b7b9046e9
--- /dev/null
+++ b/.github/workflows/yjit-ubuntu.yml
@@ -0,0 +1,170 @@
+name: YJIT Ubuntu
+on:
+  push:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+  pull_request:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+  merge_group:
+    paths-ignore:
+      - 'doc/**'
+      - '**/man'
+      - '**.md'
+      - '**.rdoc'
+      - '**/.document'
+
+concurrency:
+  group: ${{ github.workflow }} / ${{ startsWith(github.event_name, 'pull') && github.ref_name || github.sha }}
+  cancel-in-progress: ${{ startsWith(github.event_name, 'pull') }}
+
+permissions:
+  contents: read
+
+jobs:
+  cargo:
+    name: Rust cargo test
+    # GitHub Action's image seems to already contain a Rust 1.58.0.
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      # For now we can't run cargo test --offline because it complains about the
+      # capstone dependency, even though the dependency is optional
+      #- run: cargo test --offline
+      - run: RUST_BACKTRACE=1 cargo test
+        working-directory: yjit
+      # Also compile and test with all features enabled
+      - run: RUST_BACKTRACE=1 cargo test --all-features
+        working-directory: yjit
+      # Check that we can build in release mode too
+      - run: cargo build --release
+        working-directory: yjit
+  make:
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - test_task: 'yjit-bindgen'
+            hint: 'To fix: use patch in logs'
+            configure: '--with-gcc=clang-14 --enable-yjit=dev'
+            libclang_path: '/usr/lib/llvm-14/lib/libclang.so.1'
+
+          - test_task: "check"
+            # YJIT should be automatically built in release mode on x86-64 Linux with rustc present
+            #configure: "--enable-yjit RUSTC='rustc +1.58.0'"
+            configure: "RUSTC='rustc +1.58.0'"
+            rust_version: "1.58.0"
+
+          - test_task: "check"
+            configure: "--enable-yjit=dev"
+
+          - test_task: "check"
+            configure: "--enable-yjit=dev"
+            yjit_opts: "--yjit-call-threshold=1 --yjit-verify-ctx"
+
+          - test_task: "test-all TESTS=--repeat-count=2"
+            configure: "--enable-yjit=dev"
+
+          - test_task: "test-bundled-gems"
+            configure: "--enable-yjit=dev"
+
+          - test_task: "yjit-bench"
+            configure: "--enable-yjit=dev"
+            yjit_bench_opts: "--yjit-stats"
+    env:
+      GITPULLOPTIONS: --no-tags origin ${{github.ref}}
+      RUN_OPTS: ${{ matrix.yjit_opts }}
+      YJIT_BENCH_OPTS: ${{ matrix.yjit_bench_opts }}
+      RUBY_DEBUG: ci
+      BUNDLE_JOBS: 8 # for yjit-bench
+    runs-on: ubuntu-22.04
+    if: ${{ !contains(github.event.head_commit.message, '[DOC]') && !contains(github.event.pull_request.labels.*.name, 'Documentation') }}
+    steps:
+      - run: mkdir build
+        working-directory:
+      - name: Install libraries
+        run: |
+          set -x
+          sudo apt-get update -q || :
+          sudo apt-get install --no-install-recommends -q -y build-essential libssl-dev libyaml-dev libreadline6-dev zlib1g-dev libncurses5-dev libffi-dev bison autoconf ruby
+      - name: Install Rust
+        if: ${{ matrix.rust_version }}
+        run: rustup install ${{ matrix.rust_version }} --profile minimal
+      - name: git config
+        run: |
+          git config --global advice.detachedHead 0
+          git config --global init.defaultBranch garbage
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          path: src
+      - uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
+        with:
+          path: src/.downloaded-cache
+          key: downloaded-cache
+      - name: Fixed world writable dirs
+        run: |
+          chmod -v go-w $HOME $HOME/.config
+          sudo chmod -R go-w /usr/share
+          sudo bash -c 'IFS=:; for d in '"$PATH"'; do chmod -v go-w $d; done' || :
+      - name: Set ENV
+        run: |
+          echo "GNUMAKEFLAGS=-j$((1 + $(nproc --all)))" >> $GITHUB_ENV
+      - run: ./autogen.sh
+        working-directory: src
+      - name: Run configure
+        run: ../src/configure -C --disable-install-doc --prefix=$(pwd)/install ${{ matrix.configure }}
+      - run: make incs
+      - run: make prepare-gems
+        if: ${{ matrix.test_task == 'test-bundled-gems' }}
+      - run: make -j
+      - run: make leaked-globals
+        if: ${{ matrix.test_task == 'check' }}
+      - name: Create dummy files in build dir
+        run: |
+          ./miniruby -e '(("a".."z").to_a+("A".."Z").to_a+("0".."9").to_a+%w[foo bar test zzz]).each{|basename|File.write("#{basename}.rb", "raise %(do not load #{basename}.rb)")}'
+        if: ${{ matrix.test_task == 'check' }}
+      - name: Enable YJIT through ENV
+        run: echo "RUBY_YJIT_ENABLE=1" >> $GITHUB_ENV
+      # Check that the binary was built with YJIT
+      - name: Check YJIT enabled
+        run: ./miniruby --yjit -v | grep "+YJIT"
+      - name: make ${{ matrix.test_task }}
+        run: make -s -j ${{ matrix.test_task }} RUN_OPTS="$RUN_OPTS" YJIT_BENCH_OPTS="$YJIT_BENCH_OPTS"
+        timeout-minutes: 60
+        env:
+          RUBY_TESTOPTS: "-q --tty=no"
+          TEST_BUNDLED_GEMS_ALLOW_FAILURES: ""
+          PRECHECK_BUNDLED_GEMS: "no"
+          LIBCLANG_PATH: ${{ matrix.libclang_path }}
+        continue-on-error: ${{ matrix.test_task == 'yjit-bench' }}
+      - name: Show ${{ github.event.pull_request.base.ref }} GitHub URL for yjit-bench comparison
+        run: echo "https://github.com/${BASE_REPO}/commit/${BASE_SHA}"
+        env:
+          BASE_REPO: ${{ github.event.pull_request.base.repo.full_name }}
+          BASE_SHA: ${{ github.event.pull_request.base.sha }}
+        if: ${{ matrix.test_task == 'yjit-bench' && startsWith(github.event_name, 'pull') }}
+      - uses: ruby/action-slack@0bd85c72233cdbb6a0fe01d37aaeff1d21b5fce1 # v3.2.1
+        with:
+          payload: |
+            {
+              "ci": "GitHub Actions",
+              "env": "${{ github.workflow }} / ${{ matrix.test_task }} ${{ matrix.configure }}",
+              "url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
+              "commit": "${{ github.sha }}",
+              "branch": "${{ github.ref_name }}"
+            }
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SIMPLER_ALERTS_URL }} # ruby-lang slack: ruby/simpler-alerts-bot
+        if: ${{ failure() && github.event_name == 'push' }}
+
+defaults:
+  run:
+    working-directory: build
diff --git a/.gitignore b/.gitignore
index aa6994a8dc..99d32a1825 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,44 +1,72 @@
 *-*-*.def
+*-*-*.exp
+*-*-*.lib
 *.a
 *.bak
+*.bc
+*.bundle
 *.dSYM
 *.dmyh
 *.dylib
 *.elc
+*.i
+*.ii
 *.inc
 *.log
 *.o
+*.o.tmp
+*.obj
+*.old
 *.orig
+*.pch
+*.pdb
+*.rbinc
 *.rej
+*.s
 *.sav
+*.sl
+*.so
+*.so.*
 *.swp
+*.yarb
 *~
-.*-*
 .*.list
 .*.time
 .DS_Store
+.bundle
 .ccmalloc
 .ext
 .pc
 .ppack
 .svn
+.time
+.ruby-version
 Makefile
-Makefile.old
+cygruby*.def
 extconf.h
 y.output
 y.tab.c
+*.gcda
+*.gcno
+*.gcov
+*.vscode
+lcov*.info
 
 # /
 /*-fake.rb
+/*.dll
+/*.exe
+/*.res
 /*.pc
+/*.rc
 /*_prelude.c
+/.downloaded-cache
+/.top-enc.mk
+/build*/
 /COPYING.LIB
-/ChangeLog-1.8.0
-/ChangeLog.pre-alpha
-/ChangeLog.pre1_1
+/ChangeLog
 /Doxyfile
 /GNUmakefile
-/GNUmakefile.old
 /README.atheos
 /README.fat-patch
 /README.v6
@@ -46,7 +74,9 @@ y.tab.c
 /archive
 /autom4te*.cache
 /automake
+/benchmark/benchmark-driver
 /beos
+/bmlog-*
 /breakpoints.gdb
 /config.cache
 /config.h
@@ -54,6 +84,13 @@ y.tab.c
 /config.status
 /config.status.lineno
 /configure
+/coverage/simplecov
+/coverage/simplecov-html
+/coverage/doclie
+/coverage/.last_run.json
+/coverage/.resultset.json*
+/coverage/assets
+/coverage/index.html
 /doc/capi
 /enc.mk
 /encdb.h
@@ -61,6 +98,9 @@ y.tab.c
 /goruby
 /id.[ch]
 /largefile.h
+/lcov-c-out
+/lcov-rb-out
+/lcov-out
 /lex.c
 /libruby*.*
 /miniprelude.c
@@ -76,42 +116,94 @@ y.tab.c
 /ppack
 /prelude.c
 /preview
+/probes.dmyh
 /probes.h
 /rbconfig.rb
 /rename2.h
 /repack
 /revision.h
+/revision.tmp
 /riscos
 /rubicon
 /ruby
+/ruby-runner
+/ruby-runner.h
 /ruby-man.rd.gz
+/rubyspec_temp
+/run.gdb
 /sizes.c
+/static-ruby
 /test.rb
+/test-coverage.dat
 /tmp
 /transdb.h
 /uncommon.mk
 /verconf.h
+/verconf.mk
 /web
 /yasmdata.rb
 
+# /bin/
+
+/bin/*.exe
+/bin/*.dll
+/bin/goruby
+/bin/ruby
+
 # /benchmark/
+/benchmark/bm_require.data
 /benchmark/bmx_*.rb
+/benchmark/fasta.output.*
+/benchmark/wc.input
+
+/enc/*.def
+/enc/*.exp
+/enc/*.lib
+/enc/jis/props.h
+/enc/unicode/data
+
+# /coroutine/
+!/coroutine/**/*.s
 
 # /enc/trans/
 /enc/trans/*.c
+/enc/trans/*.def
+/enc/trans/*.exp
+/enc/trans/*.lib
+
+# /exe/
+/exe/goruby
+/exe/ruby
 
 # /ext/
 /ext/extinit.c
+/ext/configure-ext.mk
+/ext/*/exts.mk
+
+# /ext/-test-/cxxanyargs
+/ext/-test-/cxxanyargs/failure*.failed
+
+# /ext/-test-/win32/dln/
+/ext/-test-/win32/dln/dlntest.dll
+/ext/-test-/win32/dln/dlntest.exp
+/ext/-test-/win32/dln/dlntest.lib
 
-# /ext/dl/callback/
-/ext/dl/callback/callback-*.c
-/ext/dl/callback/callback.c
+# /ext/-test-/gems
+/ext/-test-/gems
+
+# /ext/etc/
+/ext/etc/constdefs.h
+
+# /ext/fiddle/
+/ext/fiddle/libffi-*
 
 # /ext/rbconfig/
 /ext/rbconfig/sizeof/sizes.c
+/ext/rbconfig/sizeof/limits.c
 
 # /ext/ripper/
 /ext/ripper/eventids1.c
+/ext/ripper/.eventids2-check
 /ext/ripper/eventids2table.c
 /ext/ripper/ripper.*
 /ext/ripper/ids1
@@ -122,12 +214,20 @@ y.tab.c
 /ext/socket/constdefs.h
 /ext/socket/constdefs.c
 
-# /ext/tk/
-/ext/tk/config_list
+# /gems
+/gems/*.gem
+/gems/src
+/gems/*-*
+
+# /lib/
+/lib/ruby/[1-9]*.*
+/lib/ruby/vendor_ruby
+
+# /misc/
+/misc/**/__pycache__
 
-# /spec/
-/spec/mspec
-/spec/rubyspec
+# /spec/bundler
+/.rspec_status
 
 # /tool/
 /tool/config.guess
@@ -135,4 +235,16 @@ y.tab.c
 
 # /win32/
 /win32/*.ico
-/win32/.time
+
+# MJIT
+/include/ruby-*/*/rb_mjit_min_header-*.h
+/lib/ruby_vm/mjit/instruction.rb
+/mjit_config.h
+/rb_mjit_header.h
+
+# YJIT
+/yjit-bench
+/yjit_exit_locations.dump
+
+# /wasm/
+/wasm/tests/*.wasm
diff --git a/.indent.pro b/.indent.pro
index 6a207a0554..1d61cbcad1 100644
--- a/.indent.pro
+++ b/.indent.pro
@@ -2,12 +2,15 @@
 -nbbb
 -nbc
 -br
+-brs
 -nbs
 -ncdb
--ce
--cli0.5
+-nce
+-cdw
+-cli2
+-cbi2
 -ndj
--ei
+-ncs
 -nfc1
 -i4
 -l120
@@ -16,6 +19,14 @@
 -psl
 -sc
 -sob
+-sbi4
+-nut
+-par
 
 -TID
 -TVALUE
+-Tst_data_t
+-Tst_index_t
+-Tst_table
+-Trb_data_type_t
+-TFILE
diff --git a/.rdoc_options b/.rdoc_options
new file mode 100644
index 0000000000..760507c7a2
--- /dev/null
+++ b/.rdoc_options
@@ -0,0 +1,4 @@
+---
+page_dir: doc
+main_page: README.md
+title: Documentation for Ruby development version
diff --git a/.rspec_parallel b/.rspec_parallel
new file mode 100644
index 0000000000..aaff198a32
--- /dev/null
+++ b/.rspec_parallel
@@ -0,0 +1,2 @@
+--format progress
+--format ParallelTests::RSpec::RuntimeLogger --out tmp/parallel_runtime_rspec.log
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 8db00587d6..0000000000
--- a/.travis.yml
+++ /dev/null
@@ -1,86 +0,0 @@
-# Copyright (C) 2011 Urabe, Shyouhei.  All rights reserved.
-#
-# This file is  a part of the programming language  Ruby.  Permission is hereby
-# granted,  to either  redistribute  or  modify this  file,  provided that  the
-# conditions  mentioned in  the file  COPYING are  met.  Consult  the  file for
-# details.
-
-# This is  a Travis-CI  build configuration file.   The list  of configurations
-# available is located in
-#
-#     http://about.travis-ci.org/docs/user/build-configuration/
-#
-# and as Ruby itself is a project written in C language,
-#
-#     http://about.travis-ci.org/docs/user/languages/c/
-#
-# is also a good place to look at.
-
-# Language specification.
-language: c
-
-# Compilers.  Several  compilers are  provided in Travis,  so we try  them all.
-# The value set here is visible via $CC environment variable.
-compiler:
-  - gcc
-  - clang
-
-# Dependencies.  Some  header files are missing  in a Travis' worker  VM, so we
-# have  to install  them.  The  "1.9.1" here  is OK.   It is  the  most adopted
-# version string  for Debian/Ubuntu, and  no dependencies have been  changed so
-# far since the 1.9.1 release.
-before_install:
-  - "sudo apt-get -qq update"
-  - "sudo apt-get -qq install $CC" # upgrade if any
-install: "sudo apt-get -qq build-dep ruby1.9.1 2>/dev/null"
-
-# Script is where the test runs.  Note  we just do "make test", not other tests
-# like  test-all, test-rubyspec.   This is  because  they take  too much  time,
-# enough for Travis to shut down the VM as being stalled.
-before_script:
-  - "make -f common.mk BASERUBY=ruby srcdir=. update-config_files"
-  - "autoconf"
-  - "mkdir config_1st config_2nd"
-  - "./configure -C --with-gcc=$CC"
-  - "cp -pr config.status .ext/include config_1st"
-  - "make reconfig"
-  - "cp -pr config.status .ext/include config_2nd"
-  - "diff -ru config_1st config_2nd"
-  - "make -sj encs"
-  - "make -sj exts"
-script:
-  - "make test OPTS=-v"
-#  - "make test-all TESTS='-v'"
-
-# Branch matrix.  Not all branches are Travis-ready so we limit branches here.
-branches:
-  only:
-    - trunk
-    - ruby_1_9_3
-
-# We want to be notified when something happens.
-notifications:
-  irc:
-    channels:
-      - "irc.freenode.org#ruby-core"
-      - "irc.freenode.org#ruby-ja"
-    on_success: change # [always|never|change] # default: always
-    on_failure: change # [always|never|change] # default: always
-    template:
-      - "%{message} by @%{author}: See %{build_url}"
-
-  # Update ruby-head installed on Travis CI so other projects can test against it.
-  webhooks:
-    urls:
-      - "https://rubies.travis-ci.org/rebuild/ruby-head"
-    on_success: always
-    on_failure: never
-
-# Local Variables:
-# mode: YAML
-# coding: utf-8-unix
-# indent-tabs-mode: nil
-# tab-width: 4
-# fill-column: 79
-# default-justification: full
-# End:
diff --git a/BSDL b/BSDL
index a009caefea..66d93598aa 100644
--- a/BSDL
+++ b/BSDL
@@ -4,10 +4,10 @@ Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions
 are met:
 1. Redistributions of source code must retain the above copyright
-notice, this list of conditions and the following disclaimer.
+   notice, this list of conditions and the following disclaimer.
 2. Redistributions in binary form must reproduce the above copyright
-notice, this list of conditions and the following disclaimer in the
-documentation and/or other materials provided with the distribution.
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
 
 THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 100644
index 0000000000..13df6087ca
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1 @@
+See ["Contributing to Ruby"](https://docs.ruby-lang.org/en/master/contributing_md.html), which includes setup and build instructions.
diff --git a/COPYING b/COPYING
index a1f19ff99d..48e5a96de7 100644
--- a/COPYING
+++ b/COPYING
@@ -2,55 +2,55 @@ Ruby is copyrighted free software by Yukihiro Matsumoto <matz@netlab.jp>.
 You can redistribute it and/or modify it under either the terms of the
 2-clause BSDL (see the file BSDL), or the conditions below:
 
-  1. You may make and give away verbatim copies of the source form of the
-     software without restriction, provided that you duplicate all of the
-     original copyright notices and associated disclaimers.
+1. You may make and give away verbatim copies of the source form of the
+   software without restriction, provided that you duplicate all of the
+   original copyright notices and associated disclaimers.
 
-  2. You may modify your copy of the software in any way, provided that
-     you do at least ONE of the following:
+2. You may modify your copy of the software in any way, provided that
+   you do at least ONE of the following:
 
-       a) place your modifications in the Public Domain or otherwise
-          make them Freely Available, such as by posting said
-	  modifications to Usenet or an equivalent medium, or by allowing
-	  the author to include your modifications in the software.
+   a. place your modifications in the Public Domain or otherwise
+      make them Freely Available, such as by posting said
+      modifications to Usenet or an equivalent medium, or by allowing
+      the author to include your modifications in the software.
 
-       b) use the modified software only within your corporation or
-          organization.
+   b. use the modified software only within your corporation or
+      organization.
 
-       c) give non-standard binaries non-standard names, with
-          instructions on where to get the original software distribution.
+   c. give non-standard binaries non-standard names, with
+      instructions on where to get the original software distribution.
 
-       d) make other distribution arrangements with the author.
+   d. make other distribution arrangements with the author.
 
-  3. You may distribute the software in object code or binary form,
-     provided that you do at least ONE of the following:
+3. You may distribute the software in object code or binary form,
+   provided that you do at least ONE of the following:
 
-       a) distribute the binaries and library files of the software,
-	  together with instructions (in the manual page or equivalent)
-	  on where to get the original distribution.
+   a. distribute the binaries and library files of the software,
+      together with instructions (in the manual page or equivalent)
+      on where to get the original distribution.
 
-       b) accompany the distribution with the machine-readable source of
-	  the software.
+   b. accompany the distribution with the machine-readable source of
+      the software.
 
-       c) give non-standard binaries non-standard names, with
-          instructions on where to get the original software distribution.
+   c. give non-standard binaries non-standard names, with
+      instructions on where to get the original software distribution.
 
-       d) make other distribution arrangements with the author.
+   d. make other distribution arrangements with the author.
 
-  4. You may modify and include the part of the software into any other
-     software (possibly commercial).  But some files in the distribution
-     are not written by the author, so that they are not under these terms.
+4. You may modify and include the part of the software into any other
+   software (possibly commercial).  But some files in the distribution
+   are not written by the author, so that they are not under these terms.
 
-     For the list of those files and their copying conditions, see the
-     file LEGAL.
+   For the list of those files and their copying conditions, see the
+   file LEGAL.
 
-  5. The scripts and library files supplied as input to or produced as 
-     output from the software do not automatically fall under the
-     copyright of the software, but belong to whomever generated them, 
-     and may be sold commercially, and may be aggregated with this
-     software.
+5. The scripts and library files supplied as input to or produced as
+   output from the software do not automatically fall under the
+   copyright of the software, but belong to whomever generated them,
+   and may be sold commercially, and may be aggregated with this
+   software.
 
-  6. THIS SOFTWARE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
-     IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
-     WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
-     PURPOSE.
+6. THIS SOFTWARE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
+   IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+   WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+   PURPOSE.
diff --git a/COPYING.ja b/COPYING.ja
index e50d01c8d1..230376bc60 100644
--- a/COPYING.ja
+++ b/COPYING.ja
@@ -2,50 +2,50 @@
 または以下に示す条件で本プログラムを再配布できます
 2-clause BSDLについてはBSDLファイルを参照して下さい．
 
-  1. 複製は制限なく自由です．
+1. 複製は制限なく自由です．
 
-  2. 以下の条件のいずれかを満たす時に本プログラムのソースを
-     自由に変更できます．
+2. 以下の条件のいずれかを満たす時に本プログラムのソースを
+   自由に変更できます．
 
-     (a) ネットニューズにポストしたり，作者に変更を送付する
-         などの方法で，変更を公開する．
+   a.  ネットニューズにポストしたり，作者に変更を送付する
+       などの方法で，変更を公開する．
 
-     (b) 変更した本プログラムを自分の所属する組織内部だけで
-         使う．
+   b.  変更した本プログラムを自分の所属する組織内部だけで
+       使う．
 
-     (c) 変更点を明示したうえ，ソフトウェアの名前を変更する．
-         そのソフトウェアを配布する時には変更前の本プログラ
-         ムも同時に配布する．または変更前の本プログラムのソー
-         スの入手法を明示する．
+   c.  変更点を明示したうえ，ソフトウェアの名前を変更する．
+       そのソフトウェアを配布する時には変更前の本プログラ
+       ムも同時に配布する．または変更前の本プログラムのソー
+       スの入手法を明示する．
 
-     (d) その他の変更条件を作者と合意する．
+   d.  その他の変更条件を作者と合意する．
 
-  3. 以下の条件のいずれかを満たす時に本プログラムをコンパイ
-     ルしたオブジェクトコードや実行形式でも配布できます．
+3. 以下の条件のいずれかを満たす時に本プログラムをコンパイ
+   ルしたオブジェクトコードや実行形式でも配布できます．
 
-     (a) バイナリを受け取った人がソースを入手できるように，
-         ソースの入手法を明示する．
+   a.  バイナリを受け取った人がソースを入手できるように，
+       ソースの入手法を明示する．
 
-     (b) 機械可読なソースコードを添付する．
+   b.  機械可読なソースコードを添付する．
 
-     (c) 変更を行ったバイナリは名前を変更したうえ，オリジナ
-         ルのソースコードの入手法を明示する．
+   c.  変更を行ったバイナリは名前を変更したうえ，オリジナ
+       ルのソースコードの入手法を明示する．
 
-     (d) その他の配布条件を作者と合意する．
+   d.  その他の配布条件を作者と合意する．
 
-  4. 他のプログラムへの引用はいかなる目的であれ自由です．た
-     だし，本プログラムに含まれる他の作者によるコードは，そ
-     れぞれの作者の意向による制限が加えられる場合があります．
+4. 他のプログラムへの引用はいかなる目的であれ自由です．た
+   だし，本プログラムに含まれる他の作者によるコードは，そ
+   れぞれの作者の意向による制限が加えられる場合があります．
 
-     それらファイルの一覧とそれぞれの配布条件などに付いては
-     LEGALファイルを参照してください．
+   それらファイルの一覧とそれぞれの配布条件などに付いては
+   LEGALファイルを参照してください．
 
-  5. 本プログラムへの入力となるスクリプトおよび，本プログラ
-     ムからの出力の権利は本プログラムの作者ではなく，それぞ
-     れの入出力を生成した人に属します．また，本プログラムに
-     組み込まれるための拡張ライブラリについても同様です．
+5. 本プログラムへの入力となるスクリプトおよび，本プログラ
+   ムからの出力の権利は本プログラムの作者ではなく，それぞ
+   れの入出力を生成した人に属します．また，本プログラムに
+   組み込まれるための拡張ライブラリについても同様です．
 
-  6. 本プログラムは無保証です．作者は本プログラムをサポート
-     する意志はありますが，プログラム自身のバグあるいは本プ
-     ログラムの実行などから発生するいかなる損害に対しても責
-     任を持ちません．
+6. 本プログラムは無保証です．作者は本プログラムをサポート
+   する意志はありますが，プログラム自身のバグあるいは本プ
+   ログラムの実行などから発生するいかなる損害に対しても責
+   任を持ちません．
diff --git a/ChangeLog b/ChangeLog
deleted file mode 100644
index 3cfe9918c1..0000000000
--- a/ChangeLog
+++ /dev/null
@@ -1,835 +0,0 @@
-Tue Jan 21 20:14:55 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* thread_pthread.c (rb_thread_create_timer_thread): fix for platforms
-	  where PTHREAD_STACK_MIN is a dynamic value and not a compile-time
-	  constant.  [ruby-dev:47911] [Bug #9436]
-
-Tue Jan 21 17:55:09 2014  Zachary Scott  <e@zzak.io>
-
-	* lib/uri/common.rb: [DOC] Use static w3.org uri [ci skip]
-	  Patch by @ykzts [Fix GH-484] https://github.com/ruby/ruby/pull/484
-
-Tue Jan 21 16:43:22 2014  Zachary Scott  <e@zzak.io>
-
-	* enum.c: [DOC] Add simple example of Enumerable#zip [ci skip]
-	  Patch by @nruth on documenting-ruby/ruby#22
-	  https://github.com/documenting-ruby/ruby/pull/22
-
-Tue Jan 21 16:26:44 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* thread_pthread.c (rb_thread_create_timer_thread): expand timer
-	  thread stack size to get rid of segfault on FreeBSD/powerpc64.
-	  based on the patch by Steve Wills at [ruby-core:59923].
-	  [ruby-core:56590] [Bug #8783]
-
-Tue Jan 21 04:31:23 2014  Tanaka Akira  <akr@fsij.org>
-
-	* ext/socket/option.c: Use "int" for IP_MULTICAST_LOOP and
-	  IP_MULTICAST_TTL on Mac OS X and Windows.
-
-Tue Jan 21 00:39:15 2014  Tanaka Akira  <akr@fsij.org>
-
-	* ext/socket/option.c: Use "byte" as default argument for
-	  IP_MULTICAST_LOOP and IP_MULTICAST_TTL socket option to follow
-	  the original multicast implementation.
-
-Mon Jan 20 20:20:27 2014  Tanaka Akira  <akr@fsij.org>
-
-	* ext/socket/option.c: Use preprocessor macros to avoid repeated
-	  conditionals.
-
-Mon Jan 20 13:55:03 2014  Zachary Scott  <e@zzak.io>
-
-	* lib/rubygems/version.rb: [DOC] Use gender-neutral pronouns [ci skip]
-	* lib/rubygems/security.rb: ditto
-
-Sun Jan 19 06:38:48 2014  Benoit Daloze  <eregontp@gmail.com>
-
-	* compar.c (cmp_equal): warn for this release and still rescue
-	  standard exceptions for a nicer transition. See #7688.
-	  Partly reverts r44502.
-
-	* test/ruby/test_comparable.rb: adapt assertion to match new behavior.
-
-Sun Jan 19 06:27:18 2014  Benoit Daloze  <eregontp@gmail.com>
-
-	* test/ruby/test_comparable.rb: specify behavior for the different
-	  kind of exceptions rescued (or not) by Comparable#==.
-
-Sat Jan 18 23:12:19 2014  Tanaka Akira  <akr@fsij.org>
-
-	* ext/socket: Avoid unnecessary ppoll/select on Linux.
-	  Patch by Eric Wong.  [ruby-core:57950] [Bug #9039]
-
-Sat Jan 18 22:57:44 2014  Tanaka Akira  <akr@fsij.org>
-
-	* lib/resolv.rb (Resolv::DNS::Resource::TXT#data): Return concatenated
-	  string.
-	  Patch by Ryan Brunner.  [ruby-core:58220] [Bug #9093]
-
-Sat Jan 18 22:35:15 2014  Tanaka Akira  <akr@fsij.org>
-
-	* io.c (rb_update_max_fd): Return immediately if the given fd is small
-	  enough.
-
-Sat Jan 18 22:25:53 2014  Tanaka Akira  <akr@fsij.org>
-
-	* io.c: Test O_CLOEXEC only once.
-	  Patch by Eric Wong.  [ruby-core:59419] [Feature #9328]
-
-Sat Jan 18 21:24:49 2014  Tanaka Akira  <akr@fsij.org>
-
-	* ext/socket/option.c: IP_MULTICAST_LOOP and IP_MULTICAST_TTL socket
-	  option takes a byte on OpenBSD.
-	  Fixed by Jeremy Evans.  [ruby-core:59496] [Bug #9350]
-
-Sat Jan 18 21:19:04 2014  Tanaka Akira  <akr@fsij.org>
-
-	* lib/open-uri.rb: Make proxy disabling working again.
-	  Fixed by Christophe Philemotte.   [ruby-core:59650] [Bug #9385]
-
-Fri Jan 17 20:05:02 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* lib/delegate.rb (Delegator): keep source information methods
-	  which start and end with '__'.  [ruby-core:59718] [Bug #9403]
-
-Fri Jan 17 17:58:04 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* eval.c (rb_mod_s_constants): return its own constants for other
-	  than Module itself.  [ruby-core:59763] [Bug #9413]
-
-Tue Jan 16 00:17:00 2014  Kenta Murata  <mrkn@mrkn.jp>
-
-	* ext/bigdecimal/bigdecimal.gemspec: bigdecimal version 1.2.5.
-
-Wed Jan 15 20:30:31 2014  Masaki Matsushita  <glass.saga@gmail.com>
-
-	* io.c (io_binwrite): use writev(2) to avoid double write if available.
-
-	* configure.in: check writev(2)
-
-Wed Jan 15 14:04:33 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* string.c (get_encoding): respect BOM on pseudo encodings.
-	  [ruby-dev:47895] [Bug #9415]
-
-Wed Jan 15 14:03:47 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* string.c (get_actual_encoding): get actual encoding according to
-	  the BOM if exists.
-
-	* string.c (rb_str_inspect): use according encoding, instead of
-	  pseudo encodings, UTF-{16,32}.  [ruby-core:59757] [Bug #8940]
-
-Tue Jan 14 21:07:22 2014  Masaki Matsushita  <glass.saga@gmail.com>
-
-	* ext/thread/thread.c (rb_szqueue_clear): notify SZQUEUE_WAITERS
-	  on SizedQueue#clear. [ruby-core:59462] [Bug #9342]
-
-	* test/thread/test_queue.rb: add test. the patch is from
-	  Justin Collins.
-
-Tue Jan 14 15:58:43 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* ext/bigdecimal/bigdecimal.c (CLASS_NAME): macro to wrap
-	  depending on PRIsVALUE for 1.9.  [Backport #9406]
-
-	* ext/bigdecimal/bigdecimal.c (DECIMAL_SIZE_OF_BITS): fallback
-	  definition for 2.1 or older.  [ruby-core:59750] [Backport #9406]
-
-Tue Jan 14 11:28:44 2014  Yuki Yugui Sonoda  <yugui@google.com>
-
-	* vm_exec.c (cfp): Fixes a SEGV issue in r44554.
-	  r11 can be broken by subroutine and sometimes causes SEGV at
-	  runtime.  Use r13 instead.
-
-Tue Jan 14 02:20:00 2014  Kenta Murata  <mrkn@mrkn.jp>
-
-	* ext/bigdecimal/bigdecimal.c (BigDecimal_divide): Add an additional
-	  digit for the quotient to be compatible with bigdecimal 1.2.1 and
-	  the former.  [ruby-core:59365] [#9316] [#9305]
-
-	* test/bigdecimal/test_bigdecimal.rb: tests for the above change.
-
-	* ext/bigdecimal/bigdecimal.gemspec: bigdecimal version 1.2.4.
-
-Mon Jan 13 14:55:31 2014  Zachary Scott  <e@zzak.io>
-
-	* lib/xmlrpc/client.rb: [DOC] Remove note about SSL package on RAA
-	  Since RAA has been deprecated, and the SSL package has been replaced
-	  with net/https this statement is entirely false and should be
-	  deleted. [Bug #9152]
-
-Mon Jan 13 14:47:07 2014  Zachary Scott  <e@zzak.io>
-
-	* lib/net/smtp.rb: [DOC] Remove dead link to RAA by Giorgos Tsiftsis
-	  Fixes the following bugs: [Bug #9152] [Bug #9268] [Bug #9394]
-	* lib/open-uri.rb: ditto
-
-Mon Jan 13 14:25:55 2014  Zachary Scott  <e@zzak.io>
-
-	* ext/openssl/ossl_pkey_dh.c: Fixed typo by Sandor Sz?cs [Bug #9243]
-
-Mon Jan 13 12:03:00 2014  Charlie Somerville  <charliesome@ruby-lang.org>
-
-	* ext/thread/thread.c (rb_szqueue_push): check GET_SZQUEUE_WAITERS
-	  instead of GET_QUEUE_WAITERS to prevent deadlock. Patch by Eric Wong.
-	  [Bug #9302] [ruby-core:59324]
-
-	* test/thread/test_queue.rb: add test
-
-Sun Jan 12 16:41:10 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* iseq.c (iseq_load): keep type_map to get rid of memory leak.
-	  based on a patch by Eric Wong at [ruby-core:59699].  [Bug #9399]
-
-Sun Jan 12 09:21:35 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* include/ruby/util.h (DECIMAL_SIZE_OF_BITS): a preprocessor
-	  constant macro to approximate decimal representation size of n-bits
-	  integer.
-
-	* iseq.c (register_label): use DECIMAL_SIZE_OF_BITS for better
-	  approximation.
-
-	* ext/bigdecimal/bigdecimal.c (BigMath_s_log): ditto.
-
-	* common.mk (iseq.o), ext/bigdecimal/depend (bigdecimal.o): add
-	  dependency to ruby/util.h for DECIMAL_SIZE_OF_BITS.
-
-Fri Jan 10 16:27:20 2014  Yuki Yugui Sonoda  <yugui@google.com>
-
-	* vm_exec.c (cfp): Avoid generating invalid binary for
-	  NativeClient.
-	  r15 on x86_64 is reserved by NativeClient.  So r15 to cfp used to
-	  generate invalid binary under some combinations of compiler
-	  optimization flags.
-
-Fri Jan 10 18:01:41 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* vm_insnhelper.c (vm_search_super_method): allow bound method from a
-	  module, yet another method transplanting.
-
-Fri Jan 10 13:34:04 2014  Aman Gupta <ruby@tmm1.net>
-
-	* insns.def (opt_aref_with): new instruction to optimize Hash#[],
-	  removing any allocation overhead when used with a string literal
-	  key. Patch by normalperson (Eric Wong). [ruby-core:59640] [Bug #9382]
-	* insns.def (opt_aset_with): new instruction to optimize Hash#[]=
-	* compile.c (iseq_compile_each): compiler shortcuts for new
-	  instructions
-	* hash.c (static VALUE rb_hash_compare_by_id_p): fix documentation for
-	  Hash#compare_by_identity to reflect frozen string sharing
-	* test/ruby/test_hash.rb (class TestHash): test for new behavior
-
-Fri Jan 10 06:23:21 2014  Benoit Daloze  <eregontp@gmail.com>
-
-	* range.c (Range#size): [DOC] improve description and add examples.
-	  Patch by @skade. [Fixes GH-501]
-
-Fri Jan 10 00:47:52 2014  Josef Stribny  <strzibny@gmail.com>
-
-	* ext/tk/extconf.rb: fix to pass arrays instead of strings to
-	  libpathflag.  patch at [ruby-core:59665].  [Bug #9386]
-
-Thu Jan  9 20:49:22 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* configure.in: -mstackrealign is necessary for -msse2 working.
-	  [ruby-core:54716] [Bug #8349]
-
-	* configure.in: use SSE2 instructions to drop unexpected precisions on
-	  other than mingw.  [ruby-core:59472] [Bug #8358]
-
-Thu Jan  9 20:31:10 2014  NAKAMURA Usaku  <usa@ruby-lang.org>
-
-	* hash.c (rb_objid_hash): should return `long'.  brushup r44534.
-
-	* object.c (rb_obj_hash): follow above change.
-
-Thu Jan  9 19:12:37 2014  Koichi Sasada  <ko1@atdot.net>
-
-	* vm.c (rb_vm_pop_cfunc_frame): added.  It cares c_return event.
-	  The patch base by drkaes (Stefan Kaes).
-	  [Bug #9321]
-
-	* variable.c (rb_mod_const_missing): use rb_vm_pop_cfunc_frame()
-	  instead of rb_frame_pop().
-
-	* vm_eval.c (raise_method_missing): ditto.
-
-	* vm_eval.c (rb_iterate): ditto.
-
-	* internal.h (rb_vm_pop_cfunc_frame): add decl.
-
-	* test/ruby/test_settracefunc.rb: add tests.
-	  provided by drkaes (Stefan Kaes).
-
-	* vm.c, eval.c, include/ruby/intern.h (rb_frame_pop):
-	  move definition of rb_frame_pop() and deprecate it.
-	  It doesn't care about `return' events.
-
-Thu Jan  9 17:40:28 2014  NAKAMURA Usaku  <usa@ruby-lang.org>
-
-	* hash.c (rb_any_hash): should treat the return value of rb_objid_hash()
-	  as `long', because ruby assumes the hash value of the object id of
-	  an object is `long'.
-	  this fixes test failures on mswin64 introduced at r44525.
-
-Thu Jan  9 09:55:20 2014  Aaron Patterson <aaron@tenderlovemaking.com>
-
-	* ext/psych/lib/psych/visitors/yaml_tree.rb: dumping strings with
-	  quotes should not have changed.  [ruby-core:59316] [Bug #9300]
-
-	* ext/psych/lib/psych.rb: fixed missing require.
-
-	* test/psych/test_string.rb: test
-
-Thu Jan  9 09:51:00 2014  Aaron Patterson <aaron@tenderlovemaking.com>
-
-	* ext/psych/lib/psych/visitors/to_ruby.rb: anonymous structs
-	  should be able to roundtrip.  Thanks @splattael!
-
-	* test/psych/test_object_references.rb: test for change
-
-Wed Jan  8 22:53:16 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* vm_insnhelper.c (vm_search_super_method): when super called in a
-	  bound UnboundMethod generated from a module, no superclass is
-	  found since the current defined class is the module, then call
-	  method_missing in that case.  [ruby-core:59619] [Bug #9377]
-
-Wed Jan  8 15:55:21 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* hash.c (rb_objid_hash): return hash value from object ID with a
-	  salt, extract from rb_any_hash().
-
-	* object.c (rb_obj_hash): return same value as rb_any_hash().
-	  fix r44125.  [ruby-core:59638] [Bug #9381]
-
-Wed Jan  8 13:12:41 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* lib/timeout.rb (Timeout::ExitException.catch): pass arguments
-	  for new instance.
-
-	* lib/timeout.rb (Timeout::ExitException#exception): fallback to
-	  Timeout::Error if couldn't throw.  [ruby-dev:47872] [Bug #9380]
-
-	* lib/timeout.rb (Timeout#timeout): initialize ExitException with
-	  message for the fallback case.
-
-Tue Jan  7 12:43:06 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* lib/timeout.rb (Timeout#timeout): should not rescue ordinarily
-	  raised ExitException, which should not be thrown.
-
-	* lib/timeout.rb (Timeout::ExitException.catch): set @thread only if
-	  it ought to be caught.
-
-	* lib/timeout.rb (Timeout#timeout): when a custom exception is given,
-	  no instance is needed to be caught, so defer creating new instance
-	  until it is raised.  [ruby-core:59511] [Bug #9354]
-
-Tue Jan  7 10:16:02 2014  Eric Hodel  <drbrain@segment7.net>
-
-	* lib/rubygems:  Update to RubyGems master 21e409d / RubyGems 2.2.1.
-
-	  See http://rubygems.rubyforge.org/rubygems-update/History_txt.html
-	  for a list of bug fixes.
-
-	* test/rubygems:  ditto.
-
-Tue Jan  7 10:10:46 2014  Eric Wong <e@80x24.org>
-
-	* ext/json/generator/depend: add build dependencies for json extension
-	  [Bug #9374] [ruby-core:59609]
-	* ext/json/parser/depend: ditto
-
-Tue Jan  7 04:35:46 2014  Aman Gupta <ruby@tmm1.net>
-
-	* array.c (ary_add_hash): Fix consistency issue between Array#uniq and
-	  Array#uniq! [Bug #9340] [ruby-core:59457]
-	* test/ruby/test_array.rb (class TestArray): regression test for above.
-
-Mon Jan  6 21:28:48 2014  Kazuhiro NISHIYAMA  <zn@mbf.nifty.com>
-
-	* .gitignore: ignore *-fake.rb generated even when CROSS_COMPILING = no
-	  since r42862.
-
-Sun Jan  5 20:14:14 2014  Benoit Daloze  <eregontp@gmail.com>
-
-	* compar.c (cmp_equal): remove error hiding in Comparable#==.
-	  Comparable#== no longer rescues exceptions silently.
-	  This was the cause of quite a couple bugs. See #7688. [EXPERIMENTAL]
-
-	* test/ruby/test_comparable.rb: adapt assertion to match new behavior.
-
-	* lib/rdoc/method_attr.rb: fix bugs discovered by this change.
-
-	* test/rdoc/test_rdoc_normal_class.rb: fix bugs in tests.
-
-Sat Jan  4 22:44:00 2014  Charlie Somerville  <charliesome@ruby-lang.org>
-
-	* struct.c (rb_struct_set): return assigned value from setter method
-	  rather than struct object. [Bug #9353] [ruby-core:59509]
-
-	* test/ruby/test_struct.rb (test_setter_method_returns_value): add test
-
-Sat Jan  4 21:44:31 2014  Kazuhiro NISHIYAMA  <zn@mbf.nifty.com>
-
-	* test/ruby/test_gc.rb (TestGc#test_latest_gc_info): use
-	  GC.stat(:key) instead of GC.stat.
-
-Sat Jan  4 19:15:29 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* ext/socket/socket.c (rsock_syserr_fail_host_port): use format flags,
-	  '+' to inspect, ' ' to quote unprintables.
-
-	* ext/socket/socket.c (rsock_syserr_fail_path): ditto.
-
-	* ext/socket/socket.c (rsock_syserr_fail_raddrinfo): ditto.
-
-	* ext/socket/socket.c (rsock_syserr_fail_host_port): add errno
-	  argument version and use rb_syserr_fail_str() instead of
-	  rb_sys_fail_str() with restoring errno.
-
-	* ext/socket/socket.c (rsock_syserr_fail_path): ditto, and
-	  rb_syserr_fail().
-
-	* ext/socket/socket.c (rsock_sys_fail_sockaddr): ditto, use
-	  rsock_syserr_fail_raddrinfo().
-
-	* ext/socket/socket.c (rsock_sys_fail_raddrinfo): ditto.
-
-	* ext/socket/socket.c (setup_domain_and_type): ditto.
-
-Sat Jan  4 17:18:58 2014  Kazuki Tsujimoto  <kazuki@callcc.net>
-
-	* vm.c (RubyVM::OPTS): get rid of a garbage character.
-
-Sat Jan  4 10:17:54 2014  Eric Hodel  <drbrain@segment7.net>
-
-	* lib/rinda/ring.rb (Rinda::RingFinger#make_socket):  Use
-	  ipv4_multicast_ttl option for portability.
-
-Sat Jan  4 10:15:47 2014  Eric Hodel  <drbrain@segment7.net>
-
-	* lib/rinda/ring.rb (Rinda::RingFinger#make_socket):  Use
-	  ipv4_multicast_loop option for portability.  Patch by Jeremy Evans.
-	  [ruby-trunk - Bug #9351]
-
-Fri Jan  3 19:09:00 2014  Eric Wong  <normalperson@yhbt.net>
-
-	* ext/socket/socket.c (rsock_sys_fail_host_port): save and restore errno
-	  before calling rb_sys_fail_str to prevent [BUG] errno == 0.
-	  Patch by Eric Wong. [ruby-core:59498] [Bug #9352]
-
-	* ext/socket/socket.c (rsock_sys_fail_path): ditto
-	* ext/socket/socket.c (rsock_sys_fail_sockaddr): ditto
-	* ext/socket/socket.c (rsock_sys_fail_raddrinfo): ditto
-	* ext/socket/socket.c (rsock_sys_fail_raddrinfo_or_sockaddr): ditto
-
-Fri Jan  3 10:43:57 2014  Aman Gupta <ruby@tmm1.net>
-
-	* test/net/imap/cacert.pem: generate new CA cert, since the last one
-	  expired. [Bug #9341] [ruby-core:59459]
-	* test/net/imap/server.crt: new server cert signed with updated CA.
-	* test/net/imap/Makefile: add `make regen_certs` to automate this
-	  process.
-
-Fri Jan  3 00:09:54 2014  Benoit Daloze  <eregontp@gmail.com>
-
-	* ext/bigdecimal: update class method call style from :: to .
-	  in documentation and usage.
-
-	* ext/bigdecimal/lib/bigdecimal/math.rb: [DOC] fix examples values.
-	  Computations were made using ruby 2.0.0p247 to ensure
-	  no effect of the recent BigDecimal bug.
-
-	* ext/bigdecimal/sample/nlsolve.rb: fix indent.
-
-Thu Jan  2 16:07:21 2014  Masaki Matsushita  <glass.saga@gmail.com>
-
-	* io.c (io_fwrite): freeze converted str.
-
-Thu Jan  2 04:15:13 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* eval.c (rb_longjmp): remove an extra modifier from the forward
-	  declaration to match the actual definition.  [ruby-core:59451]
-	  [Bug #9338]
-
-Thu Jan  2 01:23:30 2014  Masaki Matsushita  <glass.saga@gmail.com>
-
-	* vm_eval.c (method_missing): use ALLOCV_N() instead of
-	  ALLOCA_N() and rb_ary_tmp_new().
-
-Thu Jan  2 00:53:16 2014  Masaki Matsushita  <glass.saga@gmail.com>
-
-	* array.c (rb_ary_zip): use ALLOCV_N() instead of ALLOCA_N().
-
-Thu Jan  2 00:04:29 2014  Masaki Matsushita  <glass.saga@gmail.com>
-
-	* hash.c (rb_hash_keys): make rb_hash_keys() static.
-	  it is no longer used from array.c since r43969.
-	  the patch is from normalperson (Eric Wong).
-	  [ruby-core:59449] [Feature #9336]
-
-	* internal.h: remove definition of rb_hash_keys().
-
-Wed Jan  1 18:19:35 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* configure.in: reset LDFLAGS and DLDFLAGS for opt-dir again after
-	  LIBPATHFLAG and RPATHFLAG are set.  [ruby-dev:47868] [Bug #9317]
-
-Wed Jan  1 11:12:29 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* configure.in: use SSE2 instructions for drop unexpected
-	  precisions.  [ruby-core:54738] [Bug #8358]
-
-Tue Dec 31 23:49:07 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* eval.c (rb_f_raise): add cause: optional keyword argument.
-	  [ruby-core:58610] [Feature #8257] [EXPERIMENTAL]
-
-Tue Dec 31 21:44:17 2013  Akio Tajima <artonx@yahoo.co.jp>
-
-	* win32/Makefile.sub: remove HAVE_FSEEKO because fseeko removed from win32/win32.c
-	  Fixed [Bug #9333].
-
-Tue Dec 31 21:02:27 2013  Masaki Matsushita  <glass.saga@gmail.com>
-
-	* io.c (io_fwrite): allocate frozen str only when str is not converted.
-
-Tue Dec 31 15:44:48 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* lib/mkmf.rb (RbConfig): expand RUBY_SO_NAME for extensions
-	  backward compatibility.  [ruby-core:59426] [Bug #9329]
-
-Mon Dec 30 23:33:07 2013  Ayumu AIZAWA  <ayumu.aizawa@gmail.com>
-
-	* variable.c: [DOC] adding extra example in docs.
-	  patched by Steve Klabnik. [Bug #9210]
-
-Mon Dec 30 18:34:18 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* encoding.c (must_encindex, rb_enc_from_index, rb_obj_encoding): mask
-	  encoding index and ignore dummy flags.  [ruby-core:59354] [Bug #9314]
-
-Mon Dec 30 16:11:52 2013  WATANABE Hirofumi  <eban@ruby-lang.org>
-
-	* tool/make-snapshot: needs CXXFLAGS.  [ruby-core:59393][Bug #9320]
-
-Sun Dec 29 18:36:54 2013  Shota Fukumori  <her@sorah.jp>
-
-	* lib/mkmf.rb (configuration): Make CXXFLAGS customizable.
-	  Patch by Kohei Suzuki (eagletmt). [Fixes GH-492]
-
-Sun Dec 29 12:11:11 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* proc.c (mnew_from_me): keep iclass as-is, to make inheritance
-	  chain consistent.  [ruby-core:59358] [Bug #9315]
-
-	* proc.c (method_owner): return the original defined_class from
-	  prepended iclass, instead.
-
-Sun Dec 29 08:47:24 2013  Lucas Allan Amorim  <lucas.allan@gmail.com>
-
-	* test/ruby/test_sprintf.rb (test_hash): Added tests for sprintf
-	  with a hash as parameter.  [Fixes GH-491]
-
-Sun Dec 29 07:27:51 2013  Benoit Daloze  <eregontp@gmail.com>
-
-	* compar.c (cmp_eq_recursive): Fix the return value, the value for
-	  failed #<=> should be nil. It was raising a NoMethodError for
-	  the test case TestComparable#test_no_cmp (undefined method `>'
-	  for false:FalseClass). Yet one more reason for #7688.
-
-Sat Dec 28 22:21:59 2013  Benoit Daloze  <eregontp@gmail.com>
-
-	* object.c (Kernel#<=>) surround Comparable operators with <code> tags.
-	  The #== method was hidden in ri/rdoc's output and was highlighting
-	  the line instead.
-
-Sat Dec 28 17:24:00 2013  DV Suresh  <e@dvsuresh.me>
-
-	* benchmark/bm_so_meteor_contest.rb: [DOC] Fix a few typos
-	* ext/fiddle/lib/fiddle/import.rb: ditto
-	* ext/psych/lib/psych.rb: ditto
-	* ext/psych/lib/psych/nodes/sequence.rb: ditto
-	* ext/tk/lib/multi-tk.rb: ditto
-	* ext/tk/lib/tcltk.rb: ditto
-
-Sat Dec 28 00:42:37 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* parse.y (local_push_gen, local_pop_gen): save cmdarg_stack to
-	  isolate command argument state from outer scope.
-	  [ruby-core:59342] [Bug #9308]
-
-Fri Dec 27 13:25:03 2013  NAKAMURA Usaku  <usa@ruby-lang.org>
-
-	* win32/{setup.mak,Makefile.sub}: update fake.rb like
-	  template/fake.rb.in.
-
-Thu Dec 26 16:10:41 2013  NAKAMURA Usaku  <usa@ruby-lang.org>
-
-	* win32/Makefile.sub (fake.rb): should depend on version.h because
-	  if RUBY_VERSION is updated, fake.rb need to say the new version
-	  to avoid install error in rbconfig.rb.
-
-Thu Dec 26 14:25:03 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* hash.c (HASH_REJECT_COPY_EXTRA_STATES): turn off the old
-	  behavior, copying extra states by accident.
-
-Thu Dec 26 10:49:14 2013  Yukihiro Matsumoto  <matz@ruby-lang.org>
-
-	* version.h (RUBY_VERSION): 2.2.0 development has started.
-
-Thu Dec 26 10:27:53 2013  NAKAMURA Usaku  <usa@ruby-lang.org>
-
-	* tool/merger.rb (tag): support 2.1.1 semi-automatic tagging and 2.2.0
-	  explicit tagging.
-
-Thu Dec 26 06:35:25 2013  Marc-Andre Lafortune  <ruby-core@marc-andre.ca>
-
-	* proc.c: Having any mandatory keyword argument increases min arity
-	  [#9299]
-
-Thu Dec 26 06:27:08 2013  Marc-Andre Lafortune  <ruby-core@marc-andre.ca>
-
-	* proc.c: Having optional keyword arguments makes maximum arity +1,
-	  not unlimited [#8072]
-
-Thu Dec 26 01:09:57 2013  NAKAMURA Usaku  <usa@ruby-lang.org>
-
-	* tool/release.sh: make symbolic links.
-
-Thu Dec 26 00:45:33 2013  NAKAMURA Usaku  <usa@ruby-lang.org>
-
-	* tool/make-snapshot: support new version scheme.
-
-Wed Dec 25 22:44:14 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* compile.c (iseq_set_arguments): set arg_keyword_check from
-	  nd_cflag, which is set by parser.  internal ID is used for
-	  unnamed keyword rest argument, which should be separated from no
-	  keyword check.
-
-	* iseq.c (rb_iseq_parameters): if no keyword check, keyword rest is
-	  present.
-
-	* parse.y (new_args_tail_gen): set keywords check to nd_cflag, which
-	  equals to that keyword rest is not present.
-
-Wed Dec 25 22:32:19 2013  Zachary Scott  <e@zzak.io>
-
-	* lib/abbrev.rb: [DOC] rdoc format patch by Giorgos Tsiftsis [Bug #9146]
-
-Wed Dec 25 20:30:10 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* iseq.c (rb_iseq_parameters): push argument type symbol only for
-	  unnamed rest keywords argument.
-
-Wed Dec 25 20:28:48 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* proc.c (rb_iseq_min_max_arity): maximum argument is unlimited if
-	  having rest keywords argument.  [ruby-core:53298] [Bug #8072]
-
-Wed Dec 25 18:29:22 2013  Koichi Sasada  <ko1@atdot.net>
-
-	* vm_insnhelper.c (argument_error): insert dummy frame to make
-	  a backtrace object intead of modify backtrace string array.
-	  [Bug #9295]
-
-	* test/ruby/test_backtrace.rb: add a test for this patch.
-	  fix test to compare a result of Exception#backtrace with
-	  a result of Exception#backtrace_locations.
-
-Wed Dec 25 13:00:54 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* configure.in: let mingw do something black-magic, and check if
-	  _gmtime64_s() is available actually.
-
-	* win32/win32.c (gmtime_s, localtime_s): use _gmtime64_s() and
-	  _localtime64_s() if available, not depending on very confusing
-	  mingw variants macros.  based on the patch by phasis68 (Heesob
-	  Park) at [ruby-core:58764].  [ruby-core:58391] [Bug #9119]
-
-Wed Dec 25 12:33:41 2013  Yusuke Endoh  <mame@tsg.ne.jp>
-
-	* sample/trick2013/: added the award-winning entries of TRICK 2013.
-	  See https://github.com/tric/trick2013 for the contest outline.
-	  (Matz has approved the attachment.)
-
-Wed Dec 25 10:42:02 2013  Yamashita Yuu  <yamashita@geishatokyo.com>
-
-	* ext/openssl/ossl_ssl.c (Init_ossl_ssl): Declare a constant
-	  `OP_MSIE_SSLV2_RSA_PADDING` only if the macro is defined.  The
-	  `SSL_OP_MSIE_SSLV2_RSA_PADDING` has been removed from latest
-	  snapshot of OpenSSL 1.0.1.  [Fixes GH-488]
-
-Wed Dec 25 01:03:00 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* proc.c (bind_local_variables): allowing binding to list its
-	  local variables.  patch by Jack Danger Canty <jackdanger AT
-	  squareup.com> at [ruby-core:56543].  [Feature #8773]
-
-Tue Dec 24 23:20:38 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* test/fileutils/fileasserts.rb (assert_ownership_user): new
-	  assertion for user ownership.
-
-	* test/fileutils/test_fileutils.rb (test_chown_error),
-	  (test_chown_without_permission, test_chown_with_root):
-	  based on the patch by vajrasky (Vajrasky Kok) at
-	  [ruby-core:59298].  [Feature #9292]
-
-Tue Dec 24 16:28:05 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* proc.c (rb_mod_define_method): consider visibility only if self
-	  in the caller is same as the receiver, otherwise make public as
-	  well as old behavior.  [ruby-core:57747] [Bug #9005]
-	  [ruby-core:58497] [Bug #9141]
-
-	* vm.c (rb_vm_cref_in_context): return ruby level cref if self is
-	  same.
-
-Tue Dec 24 14:13:14 2013  Koichi Sasada  <ko1@atdot.net>
-
-	* README.EXT: add a refer to URL.
-
-Tue Dec 24 13:48:45 2013  Koichi Sasada  <ko1@atdot.net>
-
-	* README.EXT: add a document about RGenGC.
-	  Reviewed by havenwood.
-	  [misc #8962]
-
-	* README.EXT.ja: ditto.
-
-Tue Dec 24 12:11:43 2013  Koichi Sasada  <ko1@atdot.net>
-
-	* include/ruby/ruby.h (RARRAY_ASET): try to avoid compiler warning.
-	  [Bug #9287]
-
-Tue Dec 24 05:04:56 2013  NAKAMURA Usaku  <usa@ruby-lang.org>
-
-	* test/fileutils/test_fileutils.rb (setup): should not call
-	  Process.groups for Windows.  get rid of many errors introduced by
-	  r44364.
-
-Mon Dec 23 18:37:16 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* test/fileutils/fileasserts.rb (assert_ownership_group): new
-	  assertion for group ownership.
-
-	* test/fileutils/test_fileutils.rb (test_chown{,_verbose,_noop}):
-	  based on the patch by vajrasky (Vajrasky Kok) at
-	  [ruby-core:59281].  [Feature #9286]
-
-Mon Dec 23 15:53:45 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* hash.c (HAS_EXTRA_STATES): warn extra states only when something
-	  differ.  [ruby-core:59254] [Bug #9275]
-
-Mon Dec 23 12:42:13 2013  Marc-Andre Lafortune  <ruby-core@marc-andre.ca>
-
-	* array.c: Have to_h raise on elements that are not key-value pairs
-	  [#9239]
-
-	* enum.c: ditto
-
-Mon Dec 23 05:01:55 2013  Zachary Scott  <e@zzak.io>
-
-	* doc/syntax/methods.rdoc: [DOC] Added example for underscore
-	  conventions in method names. Also added doc to clarify encoding
-	  character set support for Ruby programs and elaborated on defining
-	  predicate and bang methods. Based on a patch by @gaurish
-	  [Fixes GH-477] https://github.com/ruby/ruby/pull/477
-
-Mon Dec 23 03:18:09 2013  Zachary Scott  <e@zzak.io>
-
-	* doc/ChangeLog-1.9.3: [DOC] Fix typos by @dvsuresh
-	  [Fixes GH-485] https://github.com/ruby/ruby/pull/485
-	* ext/openssl/ossl_config.c: ditto
-	* lib/rss/utils.rb, lib/time.rb: ditto
-	* test/ruby/envutil.rb: ditto
-
-Sun Dec 22 23:56:56 2013  Zachary Scott  <e@zzak.io>
-
-	* lib/{rake,rdoc,rss}/*, test/rexml/test_listener.rb: [DOC] Fix typos
-	  by @dvsuresh [Fixes GH-486] https://github.com/ruby/ruby/pull/486
-
-Sun Dec 22 11:08:47 2013  Eric Hodel  <drbrain@segment7.net>
-
-	* test/rubygems/test_gem_ext_builder.rb:  Fix warning due to ambiguous
-	  expression.
-
-Sun Dec 22 11:05:53 2013  Eric Hodel  <drbrain@segment7.net>
-
-	* lib/rubygems/commands/install_command.rb:  Restore gem install
-	  --ignore-dependencies for remote gems
-	* test/rubygems/test_gem_commands_install_command.rb:  Test for the
-	  above.
-
-Sun Dec 22 10:23:40 2013  Eric Hodel  <drbrain@segment7.net>
-
-	* lib/rdoc.rb:  Set RDoc to release version.
-
-Sun Dec 22 10:19:07 2013  Eric Hodel  <drbrain@segment7.net>
-
-	* lib/rubygems.rb:  Set RubyGems to release version.
-
-Sun Dec 22 10:16:08 2013  Eric Hodel  <drbrain@segment7.net>
-
-	* lib/rubygems.rb (module Gem):  Fix comment for
-	  Gem::load_path_insert_index.
-
-Sun Dec 22 04:07:55 2013  Koichi Sasada  <ko1@atdot.net>
-
-	* gc.c (ruby_gc_set_params): don't show obsolete warnings for
-	  RUBY_FREE_MIN/RUBY_HEAP_MIN_SLOTS if
-	  RUBY_GC_HEAP_FREE_SLOTS/RUBY_GC_HEAP_INIT_SLOTS are given.
-	  [Bug #9276]
-
-Sat Dec 21 13:00:20 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* file.c: remove unnecessary the source path from EEXIST error
-	  messages and show the destination path only.  [ruby-core:59202]
-	  [Feature #9263]
-
-Sat Dec 21 12:37:19 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
-
-	* lib/resolv.rb (Resolv::Hosts#lazy_initialize): should not
-	  consider encodings in hosts file.  [ruby-core:59239] [Bug #9273]
-
-	* lib/resolv.rb (Resolv::Config.parse_resolv_conf): ditto.
-
-Sat Dec 21 05:43:27 2013  NAKAMURA Usaku  <usa@ruby-lang.org>
-
-	* tool/make-snapshot: replace RUBY_PATCHLEVEL_STR in version.h to
-	  show users that this ruby is a preview/rc version.
-
-Sat Dec 21 05:03:49 2013  NAKAMURA Usaku  <usa@ruby-lang.org>
-
-	* win32/Makefile.sub (fake.rb): fixed wrong RUBY_PLATFORM, to correctly
-	  install win32.h.
-	  [ruby-core:58801][Bug #9199] reported by arton.
-
-For the changes before 2.1.0, see doc/ChangeLog-2.1.0
-For the changes before 2.0.0, see doc/ChangeLog-2.0.0
-For the changes before 1.9.3, see doc/ChangeLog-1.9.3
-For the changes before 1.8.0, see doc/ChangeLog-1.8.0
-
-Local variables:
-coding: us-ascii
-add-log-time-format: (lambda ()
-  (let* ((time (current-time))
-	 (system-time-locale "C")
-	 (diff (+ (cadr time) 32400))
-	 (lo (% diff 65536))
-	 (hi (+ (car time) (/ diff 65536))))
-  (format-time-string "%a %b %e %H:%M:%S %Y" (list hi lo) t)))
-indent-tabs-mode: t
-tab-width: 8
-change-log-indent-text: 2
-end:
-vim: tabstop=8 shiftwidth=2
diff --git a/KNOWNBUGS.rb b/KNOWNBUGS.rb
index b97a08d928..35a8e75876 100644
--- a/KNOWNBUGS.rb
+++ b/KNOWNBUGS.rb
@@ -1,5 +1,7 @@
 #
-# This test file concludes tests which point out known bugs.
+# IMPORTANT: Always keep the first 7 lines (comments),
+# even if this file is otherwise empty.
+#
+# This test file includes tests which point out known bugs.
 # So all tests will cause failure.
 #
-
diff --git a/LEGAL b/LEGAL
index 65706459cd..0423d57ac9 100644
--- a/LEGAL
+++ b/LEGAL
@@ -1,85 +1,331 @@
-LEGAL NOTICE INFORMATION
-------------------------
+# -*- rdoc -*-
+
+= LEGAL NOTICE INFORMATION
+--------------------------
 
 All the files in this distribution are covered under either the Ruby's
 license (see the file COPYING) or public-domain except some files
 mentioned below.
 
-include/ruby/oniguruma.h:
-regcomp.c:
-regenc.[ch]:
-regerror.c:
-regexec.c:
-regint.h:
-regparse.[ch]:
-enc/ascii.c
-enc/big5.c
-enc/cp949.c
-enc/emacs_mule.c
-enc/encdb.c
-enc/euc_jp.c
-enc/euc_kr.c
-enc/euc_tw.c
-enc/gb18030.c
-enc/gb2312.c
-enc/gbk.c
-enc/iso_8859_1.c
-enc/iso_8859_10.c
-enc/iso_8859_11.c
-enc/iso_8859_13.c
-enc/iso_8859_14.c
-enc/iso_8859_15.c
-enc/iso_8859_16.c
-enc/iso_8859_2.c
-enc/iso_8859_3.c
-enc/iso_8859_4.c
-enc/iso_8859_5.c
-enc/iso_8859_6.c
-enc/iso_8859_7.c
-enc/iso_8859_8.c
-enc/iso_8859_9.c
-enc/koi8_r.c
-enc/koi8_u.c
-enc/shift_jis.c
-enc/unicode.c
-enc/us_ascii.c
-enc/utf_16be.c
-enc/utf_16le.c
-enc/utf_32be.c
-enc/utf_32le.c
-enc/utf_8.c
-enc/windows_1251.c
-
-Oniguruma  ----   (C) K.Kosako <sndgk393 AT ybb DOT ne DOT jp>
-
-http://www.geocities.jp/kosako3/oniguruma/
-http://www.ruby-lang.org/cgi-bin/cvsweb.cgi/oniguruma/
-http://www.freebsd.org/cgi/cvsweb.cgi/ports/devel/oniguruma/
-
-   When this software is partly used or it is distributed with Ruby, 
-   this of Ruby follows the license of Ruby.
-
-configure:
+[addr2line.c]
+
+  A part of this file is from FreeBSD.
+
+  >>>
+    Copyright (c) 1986, 1988, 1991, 1993::
+    The Regents of the University of California.  All rights reserved.
+
+    (c) UNIX System Laboratories, Inc.
+
+    All or some portions of this file are derived from material licensed
+    to the University of California by American Telephone and Telegraph
+    Co. or Unix System Laboratories, Inc. and are reproduced herein with
+    the permission of UNIX System Laboratories, Inc.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+    4. Neither the name of the University nor the names of its contributors
+       may be used to endorse or promote products derived from this software
+       without specific prior written permission.
+
+    THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+    ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+    OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+    HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+    OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+    SUCH DAMAGE.
+
+	@(#)subr_prf.c	8.3 (Berkeley) 1/21/94
+
+
+[ccan/build_assert/build_assert.h]
+[ccan/check_type/check_type.h]
+[ccan/container_of/container_of.h]
+[ccan/str/str.h]
+
+  These files are licensed under the {CC0}[https://creativecommons.org/choose/zero/].
+
+[ccan/list/list.h]
+
+  This file is licensed under the {MIT License}[rdoc-label:label-MIT+License].
+
+[coroutine]
+
+  Unless otherwise specified, these files are licensed under the
+  {MIT License}[rdoc-label:label-MIT+License].
+
+[include/ruby/onigmo.h]
+[include/ruby/oniguruma.h]
+[regcomp.c]
+[regenc.c]
+[regenc.h]
+[regerror.c]
+[regexec.c]
+[regint.h]
+[regparse.c]
+[regparse.h]
+[enc/ascii.c]
+[enc/big5.c]
+[enc/cp949.c]
+[enc/emacs_mule.c]
+[enc/encdb.c]
+[enc/euc_jp.c]
+[enc/euc_kr.c]
+[enc/euc_tw.c]
+[enc/gb18030.c]
+[enc/gb2312.c]
+[enc/gbk.c]
+[enc/iso_8859_1.c]
+[enc/iso_8859_10.c]
+[enc/iso_8859_11.c]
+[enc/iso_8859_13.c]
+[enc/iso_8859_14.c]
+[enc/iso_8859_15.c]
+[enc/iso_8859_16.c]
+[enc/iso_8859_2.c]
+[enc/iso_8859_3.c]
+[enc/iso_8859_4.c]
+[enc/iso_8859_5.c]
+[enc/iso_8859_6.c]
+[enc/iso_8859_7.c]
+[enc/iso_8859_8.c]
+[enc/iso_8859_9.c]
+[enc/koi8_r.c]
+[enc/koi8_u.c]
+[enc/shift_jis.c]
+[enc/unicode.c]
+[enc/us_ascii.c]
+[enc/utf_16be.c]
+[enc/utf_16le.c]
+[enc/utf_32be.c]
+[enc/utf_32le.c]
+[enc/utf_8.c]
+[enc/windows_1251.c]
+[enc/windows_31j.c]
+
+  Onigmo (Oniguruma-mod) LICENSE
+
+  >>>
+    Copyright (c) 2002-2009::  K.Kosako  <sndgk393 AT ybb DOT ne DOT jp>
+    Copyright (c) 2011-2014::  K.Takata  <kentkt AT csc DOT jp>
+    All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+    ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+    OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+    HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+    OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+    SUCH DAMAGE.
+
+  Oniguruma LICENSE
+
+  >>>
+    Copyright (c) 2002-2009::  K.Kosako  <sndgk393 AT ybb DOT ne DOT jp>
+    All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+    ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+    OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+    HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+    OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+    SUCH DAMAGE.
+
+  * https://github.com/k-takata/Onigmo/
+  * https://github.com/kkos/oniguruma
+  * https://svnweb.freebsd.org/ports/head/devel/oniguruma/
+
+    When this software is partly used or it is distributed with Ruby,
+    this of Ruby follows the license of Ruby.
+
+[enc/windows_1250.c]
+[enc/windows_1252.c]
+
+  >>>
+    Copyright (c) 2006-2007::  Byte      <byte AT mail DOT kna DOT ru>
+                               K.Kosako  <sndgk393 AT ybb DOT ne DOT jp>
+    All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+    ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+    OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+    HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+    OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+    SUCH DAMAGE.
+
+[enc/cesu_8.c]
+[enc/windows_1253.c]
+[enc/windows_1254.c]
+[enc/windows_1257.c]
+
+  >>>
+    Copyright (c) 2002-2007::  K.Kosako  <sndgk393 AT ybb DOT ne DOT jp>
+    All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+    ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+    OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+    HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+    OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+    SUCH DAMAGE.
+
+[enc/trans/GB/GB12345%UCS.src]
+[enc/trans/GB/UCS%GB12345.src]
+[enc/trans/GB/GB2312%UCS.src]
+[enc/trans/GB/UCS%GB2312.src]
+
+  These files have this explanatory texts.
+
+  >>>
+    This mapping data was created from files provided by Unicode, Inc.
+    (The Unicode Consortium). The files were used to create a product supporting
+    Unicode, as explicitly permitted in the files' copyright notices.
+    Please note that Unicode, Inc. never made any claims as to fitness of these
+    files for any particular purpose, and has ceased to publish the files many
+    years ago.
+
+[enc/trans/JIS/JISX0201-KANA%UCS.src]
+[enc/trans/JIS/JISX0208\@1990%UCS.src]
+[enc/trans/JIS/JISX0212%UCS.src]
+[enc/trans/JIS/UCS%JISX0201-KANA.src]
+[enc/trans/JIS/UCS%JISX0208@1990.src]
+[enc/trans/JIS/UCS%JISX0212.src]
+
+  These files are copyrighted as the following.
+
+  >>>
+    © 2015 Unicode®, Inc.
+
+    For terms of use, see http://www.unicode.org/terms_of_use.html
+
+[enc/trans/JIS/JISX0213-1%UCS@BMP.src]
+[enc/trans/JIS/JISX0213-1%UCS@SIP.src]
+[enc/trans/JIS/JISX0213-2%UCS@BMP.src]
+[enc/trans/JIS/JISX0213-2%UCS@SIP.src]
+
+  These files are copyrighted as the following.
+
+  >>>
+    Copyright (C) 2001:: earthian@tama.or.jp, All Rights Reserved.
+    Copyright (C) 2001:: I'O, All Rights Reserved.
+    Copyright (C) 2006:: Project X0213, All Rights Reserved.
+    You can use, modify, distribute this table freely.
+
+[enc/trans/JIS/UCS@BMP%JISX0213-1.src]
+[enc/trans/JIS/UCS@BMP%JISX0213-2.src]
+[enc/trans/JIS/UCS@SIP%JISX0213-1.src]
+[enc/trans/JIS/UCS@SIP%JISX0213-2.src]
+
+  These files are copyrighted as the following.
+
+  >>>
+    Copyright (C) 2001:: earthian@tama.or.jp, All Rights Reserved.
+    Copyright (C) 2001:: I'O, All Rights Reserved.
+    You can use, modify, distribute this table freely.
+
+[enc/trans/ucm/glibc-BIG5-2.3.3.ucm]
+[enc/trans/ucm/glibc-BIG5HKSCS-2.3.3.ucm]
+
+  >>>
+    Copyright (C) 2001-2005:: International Business Machines
+                              Corporation and others.  All Rights Reserved.
+
+[enc/trans/ucm/windows-950-2000.ucm]
+[enc/trans/ucm/windows-950_hkscs-2001.ucm]
+
+  >>>
+    Copyright (C) 2001-2002:: International Business Machines
+                              Corporation and others.  All Rights Reserved.
+
+
+[configure]
 
   This file is free software.
 
-    Copyright (C) 1992, 93, 94, 95, 96 Free Software Foundation, Inc.
+  >>>
+    Copyright (C) 1992-1996, 1998-2012:: Free Software Foundation, Inc.
 
     This configure script is free software; the Free Software Foundation
     gives unlimited permission to copy, distribute and modify it.
 
-tool/config.guess:
-tool/config.sub:
+[tool/config.guess]
+[tool/config.sub]
 
   As long as you distribute these files with the file configure, they
   are covered under the Ruby's license.
 
-      Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999
-      Free Software Foundation, Inc.
+  >>>
+    Copyright 1992-2018:: Free Software Foundation, Inc.
 
     This file is free software; you can redistribute it and/or modify it
     under the terms of the GNU General Public License as published by
-    the Free Software Foundation; either version 2 of the License, or
+    the Free Software Foundation; either version 3 of the License, or
     (at your option) any later version.
 
     This program is distributed in the hope that it will be useful, but
@@ -88,54 +334,85 @@ tool/config.sub:
     General Public License for more details.
 
     You should have received a copy of the GNU General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+    along with this program; if not, see <https://www.gnu.org/licenses/>.
 
     As a special exception to the GNU General Public License, if you
     distribute this file as part of a program that contains a
     configuration script generated by Autoconf, you may include it under
-    the same distribution terms that you use for the rest of that program.
-
-parse.c:
-
-  This file is licensed under the GPL, but is incorporated into Ruby and 
+    the same distribution terms that you use for the rest of that
+    program.  This Exception is an additional permission under section 7
+    of the GNU General Public License, version 3 ("GPLv3").
+
+[tool/lib/test/*]
+[tool/lib/core_assertions.rb]
+
+  Some of methods on these files are based on MiniTest 4. MiniTest 4 is
+  distributed under the MIT License.
+
+  >>>
+    Copyright (c) Ryan Davis, seattle.rb
+
+    Permission is hereby granted, free of charge, to any person obtaining
+    a copy of this software and associated documentation files (the
+    'Software'), to deal in the Software without restriction, including
+    without limitation the rights to use, copy, modify, merge, publish,
+    distribute, sublicense, and/or sell copies of the Software, and to
+    permit persons to whom the Software is furnished to do so, subject to
+    the following conditions:
+
+    The above copyright notice and this permission notice shall be
+    included in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+    IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+    CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+    TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+    SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+[parse.c]
+[parse.h]
+
+  These files are licensed under the GPL, but are incorporated into Ruby and
   redistributed under the terms of the Ruby license, as permitted by the
   exception to the GPL below.
 
-     Copyright (C) 1984, 1989, 1990, 2000, 2001, 2002, 2003, 2004, 2005, 2006
-     Free Software Foundation, Inc.
+  >>>
+    Copyright (C) 1984, 1989-1990, 2000-2015, 2018:: Free Software Foundation, Inc.
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
 
-     This program is free software; you can redistribute it and/or modify
-     it under the terms of the GNU General Public License as published by
-     the Free Software Foundation; either version 2, or (at your option)
-     any later version.
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
 
-     This program is distributed in the hope that it will be useful,
-     but WITHOUT ANY WARRANTY; without even the implied warranty of
-     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-     GNU General Public License for more details.
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-     You should have received a copy of the GNU General Public License
-     along with this program; if not, write to the Free Software
-     Foundation, Inc., 51 Franklin Street, Fifth Floor,
-     Boston, MA 02110-1301, USA.  */
+    As a special exception, you may create a larger work that contains
+    part or all of the Bison parser skeleton and distribute that work
+    under terms of your choice, so long as that work isn't itself a
+    parser generator using the skeleton or a modified version thereof
+    as a parser skeleton.  Alternatively, if you modify or redistribute
+    the parser skeleton itself, you may (at your option) remove this
+    special exception, which will cause the skeleton and the resulting
+    Bison output files to be licensed under the GNU General Public
+    License without this special exception.
 
-  /* As a special exception, you may create a larger work that contains
-     part or all of the Bison parser skeleton and distribute that work
-     under terms of your choice, so long as that work isn't itself a
-     parser generator using the skeleton or a modified version thereof
-     as a parser skeleton.  Alternatively, if you modify or redistribute
-     the parser skeleton itself, you may (at your option) remove this
-     special exception, which will cause the skeleton and the resulting
-     Bison output files to be licensed under the GNU General Public
-     License without this special exception.
+    This special exception was added by the Free Software Foundation in
+    version 2.2 of Bison.
 
-     This special exception was added by the Free Software Foundation in
-     version 2.2 of Bison.  */
+[missing/dtoa.c]
 
-util.c (partly):
+  This file is under these licenses.
 
-    Copyright (c) 1991, 2000, 2001 by Lucent Technologies.
+  >>>
+    Copyright (c) 1991, 2000, 2001:: by Lucent Technologies.
 
     Permission to use, copy, modify, and distribute this software for any
     purpose without fee is hereby granted, provided that this entire notice
@@ -148,71 +425,74 @@ util.c (partly):
     REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
     OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
 
-win32/win32.[ch]:
+  >>>
+    Copyright (c) 2004-2008:: David Schultz <das@FreeBSD.ORG>
+                              All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+    ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+    OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+    HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+    OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+    SUCH DAMAGE.
+
+[win32/win32.c]
+[include/ruby/win32.h]
 
   You can apply the Artistic License to these files. (or GPL,
   alternatively)
 
-    Copyright (c) 1993, Intergraph Corporation
+  >>>
+    Copyright (c) 1993:: Intergraph Corporation
 
     You may distribute under the terms of either the GNU General Public
     License or the Artistic License, as specified in the perl README file.
 
-util.c (partly):
-
-   Copyright (c) 2004-2008 David Schultz <das@FreeBSD.ORG>
-   All rights reserved.
-
-   Redistribution and use in source and binary forms, with or without
-   modification, are permitted provided that the following conditions
-   are met:
-   1. Redistributions of source code must retain the above copyright
-      notice, this list of conditions and the following disclaimer.
-   2. Redistributions in binary form must reproduce the above copyright
-      notice, this list of conditions and the following disclaimer in the
-      documentation and/or other materials provided with the distribution.
-
-   THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
-   ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-   ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
-   FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
-   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
-   OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
-   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
-   LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
-   OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
-   SUCH DAMAGE.
-
-random.c
+[missing/mt19937.c]
 
   This file is under the new-style BSD license.
 
-    A C-program for MT19937, with initialization improved 2002/2/10.
+  >>>
+    A C-program for MT19937, with initialization improved 2002/2/10.::
     Coded by Takuji Nishimura and Makoto Matsumoto.
+
     This is a faster version by taking Shawn Cokus's optimization,
     Matthe Bellew's simplification, Isaku Wada's real version.
 
-    Before using, initialize the state by using init_genrand(seed) 
+    Before using, initialize the state by using init_genrand(seed)
     or init_by_array(init_key, key_length).
 
-    Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
-    All rights reserved.                          
+    Copyright (C) 1997 - 2002:: Makoto Matsumoto and Takuji Nishimura,
+                                All rights reserved.
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
     are met:
 
-      1. Redistributions of source code must retain the above copyright
-	 notice, this list of conditions and the following disclaimer.
+    1. Redistributions of source code must retain the above copyright
+       notice, this list of conditions and the following disclaimer.
 
-      2. Redistributions in binary form must reproduce the above copyright
-	 notice, this list of conditions and the following disclaimer in the
-	 documentation and/or other materials provided with the distribution.
+    2. Redistributions in binary form must reproduce the above copyright
+       notice, this list of conditions and the following disclaimer in the
+       documentation and/or other materials provided with the distribution.
 
-      3. The names of its contributors may not be used to endorse or promote 
-	 products derived from this software without specific prior written 
-	 permission.
+    3. The names of its contributors may not be used to endorse or promote
+       products derived from this software without specific prior written
+       permission.
 
     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
@@ -231,16 +511,15 @@ random.c
     http://www.math.keio.ac.jp/matumoto/emt.html
     email: matumoto@math.keio.ac.jp
 
-vsnprintf.c:
+  The Wayback Machine url: http://web.archive.org/web/19990429082237/http://www.math.keio.ac.jp/matumoto/emt.html
 
-  This file is under the old-style BSD license.  Note that the
-  paragraph 3 below is now null and void.
+[missing/procstat_vm.c]
 
-    Copyright (c) 1990, 1993
-         The Regents of the University of California.  All rights reserved.
+  This file is under the new-style BSD license.
 
-    This code is derived from software contributed to Berkeley by
-    Chris Torek.
+  >>>
+    Copyright (c) 2007:: Robert N. M. Watson
+                         All rights reserved.
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
@@ -250,14 +529,11 @@ vsnprintf.c:
     2. Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in the
        documentation and/or other materials provided with the distribution.
-    3. Neither the name of the University nor the names of its contributors
-       may be used to endorse or promote products derived from this software
-       without specific prior written permission.
 
-    THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+    THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-    ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+    ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
@@ -266,146 +542,100 @@ vsnprintf.c:
     OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     SUCH DAMAGE.
 
-    IMPORTANT NOTE:
-    --------------
-    From ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change
-    paragraph 3 above is now null and void.
-
-st.[ch]:
-missing/alloca.c:
-missing/dup2.c:
-missing/erf.c:
-missing/finite.c:
-missing/hypot.c:
-missing/isinf.c:
-missing/isnan.c:
-missing/lgamma_r.c:
-missing/memcmp.c:
-missing/memmove.c:
-missing/strchr.c:
-missing/strstr.c:
-missing/strtol.c:
-missing/tgamma.c:
-ext/digest/sha1/sha1.[ch]:
+    $FreeBSD: head/usr.bin/procstat/procstat_vm.c 261780 2014-02-11 21:57:37Z jhb $
+
+[vsnprintf.c]
+
+  This file is under the {old-style BSD license}[rdoc-label:label-Old-style+BSD+license].
+
+  >>>
+    Copyright (c) 1990, 1993::
+    The Regents of the University of California.  All rights reserved.
+
+    This code is derived from software contributed to Berkeley by
+    Chris Torek.
+
+[st.c]
+[strftime.c]
+[include/ruby/st.h]
+[missing/acosh.c]
+[missing/alloca.c]
+[missing/erf.c]
+[missing/hypot.c]
+[missing/lgamma_r.c]
+[missing/memcmp.c]
+[missing/memmove.c]
+[missing/strchr.c]
+[missing/strerror.c]
+[missing/strstr.c]
+[missing/tgamma.c]
+[ext/date/date_strftime.c]
+[ext/digest/sha1/sha1.c]
+[ext/digest/sha1/sha1.h]
 
   These files are all under public domain.
 
-missing/crypt.c:
+[missing/crypt.c]
 
-  This file is under the old-style BSD license.  Note that the
-  paragraph 3 below is now null and void.
+  This file is under the {old-style BSD license}[rdoc-label:label-Old-style+BSD+license].
 
-    Copyright (c) 1989, 1993
-    	The Regents of the University of California.  All rights reserved.
+  >>>
+    Copyright (c) 1989, 1993::
+    The Regents of the University of California.  All rights reserved.
 
     This code is derived from software contributed to Berkeley by
     Tom Truscott.
 
-    Redistribution and use in source and binary forms, with or without
-    modification, are permitted provided that the following conditions
-    are met:
-    1. Redistributions of source code must retain the above copyright
-       notice, this list of conditions and the following disclaimer.
-    2. Redistributions in binary form must reproduce the above copyright
-       notice, this list of conditions and the following disclaimer in the
-       documentation and/or other materials provided with the distribution.
-    3. Neither the name of the University nor the names of its contributors
-       may be used to endorse or promote products derived from this software
-       without specific prior written permission.
-
-    THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
-    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-    ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
-    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
-    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
-    OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
-    HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
-    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
-    OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
-    SUCH DAMAGE.
+[missing/setproctitle.c]
 
-missing/setproctitle.c
+  This file is under the {old-style BSD license}[rdoc-label:label-Old-style+BSD+license].
 
-  This file is under the old-style BSD license.  Note that the
-  paragraph 3 below is now null and void.
+  >>>
+    Copyright 2003:: Damien Miller
+    Copyright (c) 1983, 1995-1997:: Eric P. Allman
+    Copyright (c) 1988, 1993::
+    The Regents of the University of California.  All rights reserved.
 
-    Copyright 2003 Damien Miller
-    Copyright (c) 1983, 1995-1997 Eric P. Allman
-    Copyright (c) 1988, 1993
-    	The Regents of the University of California.  All rights reserved.
+[missing/strlcat.c]
+[missing/strlcpy.c]
 
-    Redistribution and use in source and binary forms, with or without
-    modification, are permitted provided that the following conditions
-    are met:
-    1. Redistributions of source code must retain the above copyright
-       notice, this list of conditions and the following disclaimer.
-    2. Redistributions in binary form must reproduce the above copyright
-       notice, this list of conditions and the following disclaimer in the
-       documentation and/or other materials provided with the distribution.
-    3. Neither the name of the University nor the names of its contributors
-       may be used to endorse or promote products derived from this software
-       without specific prior written permission.
+  These files are under an ISC-style license.
 
-    THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
-    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-    ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
-    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
-    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
-    OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
-    HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
-    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
-    OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
-    SUCH DAMAGE.
+  >>>
+    Copyright (c) 1998, 2015:: Todd C. Miller <Todd.Miller@courtesan.com>
 
-missing/strlcat.c
-missing/strlcpy.c
+    Permission to use, copy, modify, and distribute this software for any
+    purpose with or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
 
-  These files are under the new-style BSD license.
+    THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+    MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
-   Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
-   All rights reserved.
-
-   Redistribution and use in source and binary forms, with or without
-   modification, are permitted provided that the following conditions
-   are met:
-   1. Redistributions of source code must retain the above copyright
-      notice, this list of conditions and the following disclaimer.
-   2. Redistributions in binary form must reproduce the above copyright
-      notice, this list of conditions and the following disclaimer in the
-      documentation and/or other materials provided with the distribution.
-   3. The name of the author may not be used to endorse or promote products
-      derived from this software without specific prior written permission.
-
-   THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
-   INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
-   AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
-   THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
-   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
-   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
-   OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
-   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
-   OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
-   ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-missing/langinfo.c
+[missing/langinfo.c]
 
   This file is from http://www.cl.cam.ac.uk/~mgk25/ucs/langinfo.c.
   Ruby uses a modified version. The file contains the following
   author/copyright notice:
 
-  Markus.Kuhn@cl.cam.ac.uk -- 2002-03-11
-  Permission to use, copy, modify, and distribute this software
-  for any purpose and without fee is hereby granted. The author
-  disclaims all warranties with regard to this software.
+  >>>
+    Markus.Kuhn@cl.cam.ac.uk -- 2002-03-11::
+    Permission to use, copy, modify, and distribute this software
+    for any purpose and without fee is hereby granted. The author
+    disclaims all warranties with regard to this software.
 
-ext/digest/md5/md5.[ch]:
+[ext/digest/md5/md5.c]
+[ext/digest/md5/md5.h]
 
   These files are under the following license.  Ruby uses modified
   versions of them.
 
-    Copyright (C) 1999, 2000 Aladdin Enterprises.  All rights reserved.
+  >>>
+    Copyright (C) 1999, 2000:: Aladdin Enterprises.  All rights reserved.
 
     This software is provided 'as-is', without any express or implied
     warranty.  In no event will the authors be held liable for any damages
@@ -426,23 +656,27 @@ ext/digest/md5/md5.[ch]:
     L. Peter Deutsch
     ghost@aladdin.com
 
-ext/digest/rmd160/rmd160.[ch]:
+[ext/digest/rmd160/rmd160.c]
+[ext/digest/rmd160/rmd160.h]
 
   These files have the following copyright information, and by the
   author we are allowed to use it under the new-style BSD license.
 
-    AUTHOR:   Antoon Bosselaers, ESAT-COSIC
+  >>>
+    AUTHOR::  Antoon Bosselaers, ESAT-COSIC
               (Arranged for libc by Todd C. Miller)
-    DATE:     1 March 1996
+    DATE::    1 March 1996
 
-    Copyright (c) Katholieke Universiteit Leuven
+    Copyright (c):: Katholieke Universiteit Leuven
     1996, All Rights Reserved
 
-ext/digest/sha2/sha2.[ch]:
+[ext/digest/sha2/sha2.c]
+[ext/digest/sha2/sha2.h]
 
   These files are under the new-style BSD license.
 
-    Copyright 2000 Aaron D. Gifford.  All rights reserved.
+  >>>
+    Copyright 2000:: Aaron D. Gifford.  All rights reserved.
 
     Redistribution and use in source and binary forms, with or without
     modification, are permitted provided that the following conditions
@@ -468,29 +702,123 @@ ext/digest/sha2/sha2.[ch]:
     OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     SUCH DAMAGE.
 
-ext/nkf/nkf-utf8/config.h:
-ext/nkf/nkf-utf8/nkf.c:
-ext/nkf/nkf-utf8/utf8tbl.c:
+[ext/json/generator/generator.c]
+
+  The file contains the following copyright notice.
+
+  >>>
+    Copyright 2001-2004:: Unicode, Inc.
+
+    Disclaimer::
+
+      This source code is provided as is by Unicode, Inc. No claims are
+      made as to fitness for any particular purpose. No warranties of any
+      kind are expressed or implied. The recipient agrees to determine
+      applicability of information provided. If this file has been
+      purchased on magnetic or optical media from Unicode, Inc., the
+      sole remedy for any claim will be exchange of defective media
+      within 90 days of receipt.
+
+    Limitations on Rights to Redistribute This Code::
+
+      Unicode, Inc. hereby grants the right to freely use the information
+      supplied in this file in the creation of products supporting the
+      Unicode Standard, and to make copies of this file in any form
+      for internal or external distribution as long as this notice
+      remains attached.
+
+[ext/nkf/nkf-utf8/config.h]
+[ext/nkf/nkf-utf8/nkf.c]
+[ext/nkf/nkf-utf8/utf8tbl.c]
 
   These files are under the following license.  So to speak, it is
   copyrighted semi-public-domain software.
 
-    Copyright (C) 1987, Fujitsu LTD. (Itaru ICHIKAWA)
-       Everyone is permitted to do anything on this program 
-       including copying, modifying, improving,
-       as long as you don't try to pretend that you wrote it.
-       i.e., the above copyright notice has to appear in all copies.
-       Binary distribution requires original version messages.
-       You don't have to ask before copying, redistribution or publishing.
-       THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE.
+  >>>
+    Copyright (C) 1987:: Fujitsu LTD. (Itaru ICHIKAWA)
+
+    Everyone is permitted to do anything on this program
+    including copying, modifying, improving,
+    as long as you don't try to pretend that you wrote it.
+    i.e., the above copyright notice has to appear in all copies.
+    Binary distribution requires original version messages.
+    You don't have to ask before copying, redistribution or publishing.
+    THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE.
+
+[ext/psych]
+[test/psych]
+
+  The files under these directories are under the following license, except for
+  ext/psych/yaml.
+
+  >>>
+    Copyright 2009:: Aaron Patterson, et al.
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy of
+    this software and associated documentation files (the 'Software'), to deal in
+    the Software without restriction, including without limitation the rights to
+    use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+    of the Software, and to permit persons to whom the Software is furnished to do
+    so, subject to the following conditions:
 
-ext/socket/addrinfo.h:
-ext/socket/getaddrinfo.c:
-ext/socket/getnameinfo.c:
+    The above copyright notice and this permission notice shall be included in all
+    copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+    SOFTWARE.
+
+[ext/psych/yaml]
+
+  The files under this directory are under the following license.
+
+  >>>
+    Copyright (c) 2006:: Kirill Simonov
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy of
+    this software and associated documentation files (the "Software"), to deal in
+    the Software without restriction, including without limitation the rights to
+    use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+    of the Software, and to permit persons to whom the Software is furnished to do
+    so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in all
+    copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+    SOFTWARE.
+
+[ext/pty/pty.c]
+
+  >>>
+    C) Copyright 1998:: by Akinori Ito.
+
+    This software may be redistributed freely for this purpose, in full
+    or in part, provided that this entire copyright notice is included
+    on any copies of this software and applications and derivations thereof.
+
+    This software is provided on an "as is" basis, without warranty of any
+    kind, either expressed or implied, as to any matter including, but not
+    limited to warranty of fitness of purpose, or merchantability, or
+    results obtained from use of this software.
+
+[ext/socket/addrinfo.h]
+[ext/socket/getaddrinfo.c]
+[ext/socket/getnameinfo.c]
 
   These files are under the new-style BSD license.
 
-    Copyright (C) 1995, 1996, 1997, 1998, and 1999 WIDE Project.
+  >>>
+    Copyright (C) 1995, 1996, 1997, 1998, and 1999:: WIDE Project.
     All rights reserved.
 
     Redistribution and use in source and binary forms, with or without
@@ -517,17 +845,275 @@ ext/socket/getnameinfo.c:
     OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     SUCH DAMAGE.
 
-ext/win32ole/win32ole.c:
+[ext/win32ole/win32ole.c]
 
   You can apply the Artistic License to this file. (or GPL,
   alternatively)
 
-    (c) 1995 Microsoft Corporation. All rights reserved.
+  >>>
+    (c) 1995:: Microsoft Corporation. All rights reserved.
     Developed by ActiveWare Internet Corp., http://www.ActiveWare.com
 
-    Other modifications Copyright (c) 1997, 1998 by Gurusamy Sarathy
+    Other modifications Copyright (c) 1997, 1998:: by Gurusamy Sarathy
     <gsar@umich.edu> and Jan Dubois <jan.dubois@ibm.net>
- 
+
     You may distribute under the terms of either the GNU General Public
     License or the Artistic License, as specified in the README file
     of the Perl distribution.
+
+  The Wayback Machine url: http://web.archive.org/web/19970607104352/http://www.activeware.com:80/
+
+[lib/rdoc/generator/template/darkfish/css/fonts.css]
+
+  This file is licensed under the {SIL Open Font License}[http://scripts.sil.org/OFL].
+
+[spec/mspec]
+[spec/ruby]
+
+  The files under these directories are under the following license.
+
+  >>>
+    Copyright (c) 2008:: Engine Yard, Inc. All rights reserved.
+
+    Permission is hereby granted, free of charge, to any person
+    obtaining a copy of this software and associated documentation
+    files (the "Software"), to deal in the Software without
+    restriction, including without limitation the rights to use,
+    copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the
+    Software is furnished to do so, subject to the following
+    conditions:
+
+    The above copyright notice and this permission notice shall be
+    included in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+    OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+    NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+    HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+    WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+    OTHER DEALINGS IN THE SOFTWARE.
+
+[lib/rubygems.rb]
+[lib/rubygems]
+[test/rubygems]
+
+  RubyGems is under the following license.
+
+  >>>
+    RubyGems is copyrighted free software by Chad Fowler, Rich Kilmer, Jim
+    Weirich and others.  You can redistribute it and/or modify it under
+    either the terms of the {MIT license}[rdoc-label:label-MIT+License], or the conditions
+    below:
+
+    1. You may make and give away verbatim copies of the source form of the
+       software without restriction, provided that you duplicate all of the
+       original copyright notices and associated disclaimers.
+
+    2. You may modify your copy of the software in any way, provided that
+       you do at least ONE of the following:
+
+       a. place your modifications in the Public Domain or otherwise
+          make them Freely Available, such as by posting said
+          modifications to Usenet or an equivalent medium, or by allowing
+          the author to include your modifications in the software.
+
+       b. use the modified software only within your corporation or
+          organization.
+
+       c. give non-standard executables non-standard names, with
+          instructions on where to get the original software distribution.
+
+       d. make other distribution arrangements with the author.
+
+    3. You may distribute the software in object code or executable
+       form, provided that you do at least ONE of the following:
+
+       a. distribute the executables and library files of the software,
+          together with instructions (in the manual page or equivalent)
+          on where to get the original distribution.
+
+       b. accompany the distribution with the machine-readable source of
+          the software.
+
+       c. give non-standard executables non-standard names, with
+          instructions on where to get the original software distribution.
+
+       d. make other distribution arrangements with the author.
+
+    4. You may modify and include the part of the software into any other
+       software (possibly commercial).
+
+    5. The scripts and library files supplied as input to or produced as
+       output from the software do not automatically fall under the
+       copyright of the software, but belong to whomever generated them,
+       and may be sold commercially, and may be aggregated with this
+       software.
+
+    6. THIS SOFTWARE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
+       IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+       WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+       PURPOSE.
+
+[lib/bundler]
+[lib/bundler.rb]
+[spec/bundler]
+
+  Bundler is under the following license.
+
+  >>>
+    Portions copyright (c) 2010:: Andre Arko
+    Portions copyright (c) 2009:: Engine Yard
+
+    {MIT License}[rdoc-label:label-MIT+License]
+
+[lib/bundler/vendor/thor]
+
+  Thor is under the following license.
+
+  >>>
+    Copyright (c) 2008 Yehuda Katz, Eric Hodel, et al.
+
+    {MIT License}[rdoc-label:label-MIT+License]
+
+[lib/rubygems/resolver/molinillo]
+
+  molinillo is under the following license.
+
+  >>>
+    Copyright (c) 2014 Samuel E. Giddins segiddins@segiddins.me
+
+    {MIT License}[rdoc-label:label-MIT+License]
+
+[lib/bundler/vendor/pub_grub]
+
+  pub_grub is under the following license.
+
+  >>>
+    Copyright (c) 2018 John Hawthorn
+
+    {MIT License}[rdoc-label:label-MIT+License]
+
+[lib/bundler/vendor/connection_pool]
+
+  connection_pool is under the following license.
+
+  >>>
+    Copyright (c) 2011 Mike Perham
+
+    {MIT License}[rdoc-label:label-MIT+License]
+
+[lib/bundler/vendor/net-http-persistent]
+
+  net-http-persistent is under the following license.
+
+  >>>
+    Copyright (c) Eric Hodel, Aaron Patterson
+
+    {MIT License}[rdoc-label:label-MIT+License]
+
+[lib/did_you_mean]
+[lib/did_you_mean.rb]
+[test/did_you_mean]
+
+  did_you_mean is under the following license.
+
+  >>>
+    Copyright (c) 2014-2016 Yuki Nishijima
+
+    {MIT License}[rdoc-label:label-MIT+License]
+
+[lib/error_highlight]
+[lib/error_highlight.rb]
+[test/error_highlight]
+
+  error_highlight is under the following license.
+
+  >>>
+    Copyright (c) 2021 Yusuke Endoh
+
+    {MIT License}[rdoc-label:label-MIT+License]
+
+[benchmark/so_ackermann.rb]
+[benchmark/so_array.rb]
+[benchmark/so_binary_trees.rb]
+[benchmark/so_concatenate.rb]
+[benchmark/so_count_words.yml]
+[benchmark/so_exception.rb]
+[benchmark/so_fannkuch.rb]
+[benchmark/so_fasta.rb]
+[benchmark/so_k_nucleotide.yml]
+[benchmark/so_lists.rb]
+[benchmark/so_mandelbrot.rb]
+[benchmark/so_matrix.rb]
+[benchmark/so_meteor_contest.rb]
+[benchmark/so_nbody.rb]
+[benchmark/so_nested_loop.rb]
+[benchmark/so_nsieve.rb]
+[benchmark/so_nsieve_bits.rb]
+[benchmark/so_object.rb]
+[benchmark/so_partial_sums.rb]
+[benchmark/so_pidigits.rb]
+[benchmark/so_random.rb]
+[benchmark/so_reverse_complement.yml]
+[benchmark/so_sieve.rb]
+[benchmark/so_spectralnorm.rb]
+
+  These files are very old copy of then-called "The Great Computer Language
+  Shootout".  LEGAL SITUATION OF THESE FILES ARE UNCLEAR because the original
+  site has been lost.  Upstream diverged to delete several benchmarks listed
+  above.
+
+== MIT License
+>>>
+      Permission is hereby granted, free of charge, to any person obtaining
+      a copy of this software and associated documentation files (the
+      "Software"), to deal in the Software without restriction, including
+      without limitation the rights to use, copy, modify, merge, publish,
+      distribute, sublicense, and/or sell copies of the Software, and to
+      permit persons to whom the Software is furnished to do so, subject to
+      the following conditions:
+
+      The above copyright notice and this permission notice shall be
+      included in all copies or substantial portions of the Software.
+
+      THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+      EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+      MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+      NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+      LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+      OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+      WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+== Old-style BSD license
+>>>
+      Redistribution and use in source and binary forms, with or without
+      modification, are permitted provided that the following conditions
+      are met:
+      1. Redistributions of source code must retain the above copyright
+         notice, this list of conditions and the following disclaimer.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, this list of conditions and the following disclaimer in the
+         documentation and/or other materials provided with the distribution.
+      3. Neither the name of the University nor the names of its contributors
+         may be used to endorse or promote products derived from this software
+         without specific prior written permission.
+
+      THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+      ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+      IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+      ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+      FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+      DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+      OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+      HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+      LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+      OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+      SUCH DAMAGE.
+
+      IMPORTANT NOTE::
+
+      From ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change
+      paragraph 3 above is now null and void.
diff --git a/Makefile.in b/Makefile.in
deleted file mode 100644
index d3313bea2e..0000000000
--- a/Makefile.in
+++ /dev/null
@@ -1,480 +0,0 @@
-SHELL = /bin/sh
-NULLCMD = @NULLCMD@
-n=$(NULLCMD)
-ECHO1 = $(V:1=@$n)
-RUNCMD = $(SHELL)
-CDPATH = .
-CHDIR = @CHDIR@
-exec = exec
-NULL = /dev/null
-PATH_SEPARATOR = @PATH_SEPARATOR@
-
-#### Start of system configuration section. ####
-
-srcdir = @srcdir@
-top_srcdir = $(srcdir)
-hdrdir = $(srcdir)/include
-PLATFORM_DIR = @PLATFORM_DIR@
-
-CC = @CC@
-CPP = @CPP@
-LD = @LD@
-YACC = bison
-PURIFY =
-AUTOCONF = autoconf
-@SET_MAKE@
-MKFILES = @MAKEFILES@
-BASERUBY = @BASERUBY@
-TEST_RUNNABLE = @TEST_RUNNABLE@
-CROSS_COMPILING = @CROSS_COMPILING@
-DOXYGEN = @DOXYGEN@
-
-prefix = @prefix@
-exec_prefix = @exec_prefix@
-bindir = @bindir@
-sbindir = @sbindir@
-libdir = @libdir@
-libexecdir = @libexecdir@
-datarootdir = @datarootdir@
-datadir = @datadir@
-arch = @arch@
-sitearch = @sitearch@
-sitedir = @sitedir@
-archlibdir = @archlibdir@
-ruby_version = @ruby_version@
-
-TESTUI = console
-TESTS =
-INSTALLDOC = @INSTALLDOC@
-DOCTARGETS = @RDOCTARGET@ @CAPITARGET@
-
-EXTOUT = @EXTOUT@
-arch_hdrdir = $(EXTOUT)/include/$(arch)
-VPATH = $(arch_hdrdir)/ruby:$(hdrdir)/ruby:$(srcdir):$(srcdir)/enc:$(srcdir)/missing
-
-empty =
-CC_VERSION = @CC_VERSION@
-OUTFLAG = @OUTFLAG@$(empty)
-COUTFLAG = @COUTFLAG@$(empty)
-ARCH_FLAG = @ARCH_FLAG@
-CFLAGS = @CFLAGS@ $(ARCH_FLAG)
-cflags = @cflags@
-optflags = @optflags@
-debugflags = @debugflags@
-warnflags = @warnflags@ @strict_warnflags@
-cppflags = @cppflags@
-INCFLAGS = -I. -I$(arch_hdrdir) -I$(hdrdir) -I$(srcdir)
-XCFLAGS = @XCFLAGS@
-CPPFLAGS = @CPPFLAGS@ $(INCFLAGS)
-LDFLAGS = @STATIC@ $(CFLAGS) @LDFLAGS@
-EXTLDFLAGS = @EXTLDFLAGS@
-XLDFLAGS = @XLDFLAGS@ $(EXTLDFLAGS)
-EXTLIBS =
-LIBS = @LIBS@ $(EXTLIBS)
-MISSING = @LIBOBJS@ @ALLOCA@
-LDSHARED = @LIBRUBY_LDSHARED@
-DLDFLAGS = @LIBRUBY_DLDFLAGS@ $(XLDFLAGS) $(ARCH_FLAG)
-SOLIBS = @SOLIBS@
-MAINLIBS = @MAINLIBS@
-ARCHMINIOBJS = @MINIOBJS@
-DLNOBJ = @DLNOBJ@
-ENCOBJS = @ENCOBJS@
-EXTOBJS = @EXTOBJS@
-BUILTIN_ENCOBJS = @BUILTIN_ENCOBJS@
-BUILTIN_TRANSSRCS = @BUILTIN_TRANSSRCS@
-BUILTIN_TRANSOBJS = @BUILTIN_TRANSOBJS@
-POSTLINK = @POSTLINK@
-
-RUBY_BASE_NAME=@RUBY_BASE_NAME@
-RUBY_PROGRAM_VERSION=@RUBY_PROGRAM_VERSION@
-RUBY_INSTALL_NAME=@RUBY_INSTALL_NAME@
-RUBY_SO_NAME=@RUBY_SO_NAME@
-RUBY_RELEASE_DATE=@RUBY_RELEASE_DATE@
-EXEEXT = @EXEEXT@
-LIBEXT = @LIBEXT@
-PROGRAM=$(RUBY_INSTALL_NAME)$(EXEEXT)
-RUBY = $(RUBY_INSTALL_NAME)
-MINIRUBY = @MINIRUBY@\
-	$(MINIRUBYOPT)
-# RUNRUBY_COMMAND:: runruby.rb or baseruby. do not append options directly
-RUNRUBY_COMMAND = @RUNRUBY_COMMAND@
-# RUNRUBY:: run ruby with RUN_OPTS which is passed to ruby
-RUNRUBY = @RUNRUBY@ $(RUN_OPTS)
-# RUNRUBY_DEBUGGER:: debugging option for runruby.rb
-RUNRUBY_DEBUGGER = --debugger='gdb -x run.gdb --quiet --args'
-XRUBY = @XRUBY@
-BTESTRUBY = @BTESTRUBY@\
-	$(MINIRUBYOPT)
-INSTALL = @INSTALL@
-INSTALL_DATA = @INSTALL_DATA@
-INSTALL_SCRIPT = @INSTALL_SCRIPT@
-INSTALL_PROGRAM = @INSTALL_PROGRAM@
-XRUBY_LIBDIR = @XRUBY_LIBDIR@
-XRUBY_RUBYLIBDIR = @XRUBY_RUBYLIBDIR@
-XRUBY_RUBYHDRDIR = @XRUBY_RUBYHDRDIR@
-
-DEFAULT_PRELUDES = $(GEM_PRELUDE)
-
-#### End of system configuration section. ####
-
-MAJOR=	@MAJOR@
-MINOR=	@MINOR@
-TEENY=	@TEENY@
-
-LIBRUBY_A     = @LIBRUBY_A@
-LIBRUBY_SO    = @LIBRUBY_SO@
-LIBRUBY_ALIASES= @LIBRUBY_ALIASES@
-LIBRUBY	      = @LIBRUBY@
-LIBRUBYARG    = @LIBRUBYARG@
-LIBRUBYARG_STATIC = @LIBRUBYARG_STATIC@
-LIBRUBYARG_SHARED = @LIBRUBYARG_SHARED@
-LIBRUBY_RELATIVE = @LIBRUBY_RELATIVE@
-LIBRUBY_A_OBJS = @LIBRUBY_A_OBJS@
-
-THREAD_MODEL  = @THREAD_MODEL@
-
-PREP          = @PREP@
-ARCHFILE      = @ARCHFILE@
-SETUP         =
-EXTSTATIC     = @EXTSTATIC@
-SET_LC_MESSAGES = env LC_MESSAGES=C
-
-MAKEDIRS      = @MKDIR_P@
-CP            = cp
-MV            = mv
-RM            = rm -f
-RMDIR         = @RMDIR@
-RMDIRS        = @RMDIRS@
-RMALL         = @RMALL@
-NM            = @NM@
-AR            = @AR@
-ARFLAGS       = rcu
-RANLIB        = @RANLIB@
-AS            = @AS@
-ASFLAGS       = @ASFLAGS@ $(INCFLAGS)
-IFCHANGE      = $(srcdir)/tool/ifchange
-SET_LC_MESSAGES = env LC_MESSAGES=C
-OBJDUMP       = @OBJDUMP@
-OBJCOPY       = @OBJCOPY@
-VCS           = @VCS@
-VCSUP         = @VCSUP@
-DTRACE        = @DTRACE@
-DTRACE_EXT    = @DTRACE_EXT@
-DTRACE_OBJ   = @DTRACE_OBJ@
-DTRACE_GLOMMED_OBJ = @DTRACE_GLOMMED_OBJ@
-
-OBJEXT        = @OBJEXT@
-ASMEXT        = S
-DLEXT         = @DLEXT@
-MANTYPE	      = @MANTYPE@
-SYMBOL_PREFIX = @SYMBOL_PREFIX@
-
-INSTALLED_LIST= .installed.list
-
-MKMAIN_CMD    = mkmain.sh
-
-NEWLINE_C     = newline.c
-MINIPRELUDE_C = miniprelude.c
-RBCONFIG      = .rbconfig.time
-
-SRC_FILE      = $<
-OS_SRC_FILE   = $<
-DEST_FILE     = $@
-OS_DEST_FILE  = $@
-
-MESSAGE_BEGIN = @for line in
-MESSAGE_END = ; do echo "$$line"; done
-ECHO_BEGIN = @sep=''; for word in
-ECHO_END = ; do echo @ECHO_N@ "$$sep'$$word'@ECHO_C@"; sep=' '; done; echo
-
-configure_args = @configure_args@
-#### End of variables
-
-.SUFFIXES: .inc .h .c .y .i .$(DTRACE_EXT)
-
-all:
-
-.DEFAULT: all
-
-# Prevent GNU make v3 from overflowing arg limit on SysV.
-.NOEXPORT:
-
-miniruby$(EXEEXT):
-		@-if test -f $@; then $(MV) -f $@ $@.old; $(RM) $@.old; fi
-		$(ECHO) linking $@
-		$(Q) $(PURIFY) $(CC) $(LDFLAGS) $(XLDFLAGS) $(NORMALMAINOBJ) $(MINIOBJS) $(COMMONOBJS) $(DMYEXT) $(DTRACE_OBJ) $(MAINLIBS) $(LIBS) $(OUTFLAG)$@
-
-$(PROGRAM):
-		@$(RM) $@
-		$(ECHO) linking $@
-		$(Q) $(PURIFY) $(CC) $(LDFLAGS) $(XLDFLAGS) $(MAINOBJ) $(EXTOBJS) $(LIBRUBYARG) $(MAINLIBS) $(LIBS) $(EXTLIBS) $(OUTFLAG)$@
-		$(Q) $(POSTLINK)
-
-# We must `rm' the library each time this rule is invoked because "updating" a
-# MAB library on Apple/NeXT (see --enable-fat-binary in configure) is not
-# supported.
-$(LIBRUBY_A):
-		@$(RM) $@
-		$(ECHO) linking static-library $@
-		$(Q) $(AR) $(ARFLAGS) $@ $(LIBRUBY_A_OBJS) $(DMYEXT)
-		@-$(RANLIB) $@ 2> /dev/null || true
-		$(ECHO) verifying static-library $@
-		@$(PURIFY) $(CC) $(LDFLAGS) $(XLDFLAGS) $(MAINOBJ) $(LIBRUBY_A) $(MAINLIBS) $(EXTLIBS) $(LIBS) $(OUTFLAG)conftest$(EXEEXT)
-		@$(RM) conftest$(EXEEXT) conftest.c
-
-$(LIBRUBY_SO):
-		@-$(PRE_LIBRUBY_UPDATE)
-		$(ECHO) linking shared-library $@
-		$(Q) $(LDSHARED) $(DLDFLAGS) $(OBJS) $(DLDOBJS) $(DTRACE_OBJ) $(SOLIBS) $(EXTSOLIBS) $(OUTFLAG)$@
-		-$(Q) $(OBJCOPY) -w -L '$(SYMBOL_PREFIX)Init_*' -L '$(SYMBOL_PREFIX)*_threadptr_*' $@
-		$(Q) $(POSTLINK)
-		@-$(MINIRUBY) -e 'ARGV.each{|link| File.delete link rescue nil; \
-						  File.symlink "$(LIBRUBY_SO)", link}' \
-				$(LIBRUBY_ALIASES) || true
-$(arch)-fake.rb: config.status $(srcdir)/template/fake.rb.in
-		@./config.status --file=$@:$(srcdir)/template/fake.rb.in
-		@chmod +x $@
-
-ruby_pc = @ruby_pc@
-$(ruby_pc):
-		@./config.status --file=$@:$(srcdir)/template/ruby.pc.in
-
-install-cross: $(arch)-fake.rb $(RBCONFIG) rbconfig.rb $(arch_hdrdir)/ruby/config.h \
-	$(LIBRUBY_A) $(LIBRUBY_SO) $(ARCHFILE)
-	$(ECHO) installing cross-compiling stuff
-	$(Q) $(MAKEDIRS) $(XRUBY_RUBYLIBDIR)/$(arch) $(XRUBY_RUBYHDRDIR)/$(arch)/ruby
-	$(Q) sed '/^\$$:\.unshift/q' $(arch)-fake.rb > fake.rb
-	$(Q) $(BASERUBY) -p \
-	-e '~/^\s*CONFIG\["LDFLAGS"\]/ and' \
-	-e '$$_[/(?=\s*"$$)/] = %q[ #{(CONFIG["LIBPATHFLAG"]%File.dirname(__FILE__)).strip}]' \
-	rbconfig.rb > fake-rbconfig.rb
-	$(INSTALL_SCRIPT) fake.rb $(XRUBY_RUBYLIBDIR)/$(arch)/fake.rb
-	$(INSTALL_SCRIPT) fake-rbconfig.rb $(XRUBY_RUBYLIBDIR)/$(arch)/rbconfig.rb
-	@$(RM) fake.rb fake-rbconfig.rb
-	$(INSTALL_DATA) $(arch_hdrdir)/ruby/config.h $(XRUBY_RUBYHDRDIR)/$(arch)/ruby
-	$(INSTALL_DATA) $(top_srcdir)/include/ruby/win32.h $(XRUBY_RUBYHDRDIR)/ruby
-	$(INSTALL_DATA) $(LIBRUBY) $(LIBRUBY_A) $(XRUBY_RUBYLIBDIR)/$(arch)
-	$(INSTALL_PROGRAM) $(LIBRUBY_SO) $(XRUBY_RUBYLIBDIR)/$(arch)
-
-Makefile:	$(srcdir)/Makefile.in $(srcdir)/enc/Makefile.in
-
-$(MKFILES): config.status
-		@[ -f $@ ] && mv $@ $@.old
-		MAKE=$(MAKE) $(SHELL) ./config.status $@
-		@cmp $@ $@.old > /dev/null 2>&1 && echo $@ unchanged && exit 0; \
-		{ \
-		    echo "all:; -@rm -f conftest.mk"; \
-		    echo "conftest.mk: .force; @echo AUTO_REMAKE"; \
-		    echo ".force:"; \
-		} > conftest.mk || exit 1; \
-		$(MAKE) -f conftest.mk | grep '^AUTO_REMAKE$$' >/dev/null 2>&1 || \
-		{ echo "$@ updated, restart."; exit 1; }
-
-uncommon.mk: $(srcdir)/common.mk
-		sed 's/{\$$([^(){}]*)[^{}]*}//g' $< > $@
-
-.PHONY: reconfig
-reconfig-args = $(srcdir)/configure $(configure_args)
-config.status-args = ./config.status --recheck
-reconfig-exec-0 = exec 3>&1; exit `exec 4>&1; { "$$@" 3>&- 4>&-; echo $$? 1>&4; } | fgrep -v '(cached)' 1>&3`
-reconfig-exec-1 = set -x; "$$@"
-
-reconfig config.status:	$(srcdir)/configure $(srcdir)/enc/Makefile.in \
-			$(srcdir)/include/ruby/version.h
-	@PWD= MINIRUBY="$(MINIRUBY)"; export MINIRUBY; \
-	set $(SHELL) $($@-args); $(reconfig-exec-$(V))
-
-$(srcdir)/configure: $(srcdir)/configure.in
-	$(CHDIR) $(srcdir) && exec $(AUTOCONF)
-
-incs: id.h
-all-incs: probes.h
-
-# Things which should be considered:
-# * with gperf v.s. without gperf
-# * committers may have various versions of gperf
-# * ./configure v.s. ../ruby/configure
-# * GNU make v.s. HP-UX make	# HP-UX make invokes the action if lex.c and keywords has same mtime.
-# * svn checkout generate a file with mtime as current time
-# * ext4 and XFS has a mtime with fractional part
-lex.c: defs/keywords
-	@\
-	if cmp -s $(srcdir)/defs/lex.c.src $?; then \
-	  [ $(Q) ] && echo copying $@ || set -x; \
-	  $(CP) $(srcdir)/lex.c.blt $@; \
-	else \
-	  [ $(Q) ] && echo generating $@ || set -x; \
-	  gperf -C -p -j1 -i 1 -g -o -t -N rb_reserved_word -k1,3,$$ $? > $@.tmp && \
-	  $(MV) $@.tmp $@ && \
-	  $(CP) $? $(srcdir)/defs/lex.c.src && \
-	  $(CP) $@ $(srcdir)/lex.c.blt; \
-	fi
-
-NAME2CTYPE_OPTIONS = -7 -c -j1 -i1 -t -C -P -T -H uniname2ctype_hash -Q uniname2ctype_pool -N uniname2ctype_p
-
-enc/unicode/name2ctype.h: enc/unicode/name2ctype.kwd
-	$(MAKEDIRS) $(@D)
-	@set +e; \
-	if cmp -s $(?:.kwd=.src) $?; then \
-	  set -x; \
-	  $(CP) $(?:.kwd=.h.blt) $@; \
-	else \
-	  trap '$(RM) $@-1.h $@-2.h' 0 && \
-	  set -x; \
-	  sed '/^#ifdef USE_UNICODE_PROPERTIES/,/^#endif/d' $? | gperf $(NAME2CTYPE_OPTIONS) > $@-1.h && \
-	  sed '/^#ifdef USE_UNICODE_PROPERTIES/d;/^#endif/d' $? | gperf $(NAME2CTYPE_OPTIONS) > $@-2.h && \
-	  diff -DUSE_UNICODE_PROPERTIES $@-1.h $@-2.h > $@.tmp || :; \
-	  $(MV) $@.tmp $@ && \
-	  $(CP) $? $(?:.kwd=.src) && \
-	  $(CP) $@ $(?:.kwd=.h.blt); \
-	fi
-
-.c.@OBJEXT@:
-	@$(ECHO) compiling $<
-	$(Q) $(CC) $(CFLAGS) $(XCFLAGS) $(CPPFLAGS) $(COUTFLAG)$@ -c $<
-
-.s.@OBJEXT@:
-	@$(ECHO) assembling $<
-	$(Q) $(AS) $(ASFLAGS) -o $@ $<
-
-.c.S:
-	@$(ECHO) translating $<
-	$(Q) $(CC) $(CFLAGS) $(XCFLAGS) $(CPPFLAGS) $(COUTFLAG)$@ -S $<
-
-.c.i:
-	@$(ECHO) preprocessing $<
-	$(Q) $(CPP) $(warnflags) $(XCFLAGS) $(CPPFLAGS) $(COUTFLAG)$@ -E $< > $@
-
-.d.h:
-	@$(ECHO) translating probes $<
-	$(Q) $(DTRACE) -o $@.tmp -h -C $(INCFLAGS) -s $<
-	$(Q) sed -e 's/RUBY_/RUBY_DTRACE_/g' -e 's/PROBES_H_TMP/PROBES_H/g' -e 's/(char \*/(const char */g' -e 's/, char \*/, const char */g' $@.tmp > $@
-	$(Q) $(RM) $@.tmp
-
-.dmyh.h:
-	@$(ECHO) copying dummy $(DEST_FILE)
-	$(Q) $(CP) $(OS_SRC_FILE) $(OS_DEST_FILE)
-
-probes.@OBJEXT@: $(srcdir)/probes.d
-	@$(ECHO) processing probes in object files
-	$(Q) stamp="$*.stamp"; \
-	  if test -f "$$stamp" -o -f "$@"; then \
-	  $(RM) $(DTRACE_DEPENDENT_OBJS) "$$stamp"; \
-	  for o in $(DTRACE_DEPENDENT_OBJS); do \
-	    echo "rebuilding $$o which was modified by \"dtrace -G\""; \
-	    $(MAKE) "$$o"; \
-	  done; \
-	fi; \
-	touch "$$stamp"
-	$(RM) $@
-	$(Q) $(DTRACE) -G -C $(INCFLAGS) -s $(srcdir)/probes.d -o $@ $(DTRACE_DEPENDENT_OBJS)
-
-# DTrace static library hacks described here:
-# http://mail.opensolaris.org/pipermail/dtrace-discuss/2005-August/000207.html
-ruby-glommed.$(OBJEXT):
-	@$(ECHO) generating a glommed object with DTrace probes for static library
-	$(Q) $(LD) -r -o $@ $(OBJS) $(DTRACE_OBJ)
-
-clean-local::
-	$(Q)$(RM) ext/extinit.c ext/extinit.$(OBJEXT) ext/ripper/y.output \
-		enc/encinit.c enc/encinit.$(OBJEXT)
-	-$(Q)$(RM) $(pkgconfig_DATA)
-
-distclean-local::
-	$(Q)$(RM) ext/config.cache $(RBCONFIG) Doxyfile
-	-$(Q)$(RM) run.gdb
-	-$(Q)$(RM) $(INSTALLED_LIST) $(arch_hdrdir)/ruby/config.h verconf.h
-	-$(Q)$(RMDIRS) $(arch_hdrdir)/ruby 2> /dev/null || true
-
-clean-ext distclean-ext realclean-ext::
-	@cd ext 2>/dev/null || exit 0; set dummy `echo "${EXTS}" | tr , ' '`; shift; \
-	test "$$#" = 0 && set .; \
-	set dummy `\
-	    find "$$@" -name Makefile -print | sed 's:^\./::;s:/Makefile$$:~:' | sort | sed 's:~$$::'; \
-	`; shift; \
-	cd ..; \
-	for dir do \
-	    echo $(@:-ext=)ing "$$dir"; \
-	    (cd "ext/$$dir" && exec $(MAKE) $(MFLAGS) $(@:-ext=)) && \
-	    case "$@" in \
-	    *distclean-ext*|*realclean-ext*) \
-		$(RMDIRS) "ext/$$dir" 2> /dev/null || true;; \
-	    esac; \
-	done
-	-$(Q)$(RM) ext/extinit.$(OBJEXT)
-
-distclean-ext realclean-ext::
-	-$(Q)$(RM) ext/extinit.c
-	-$(Q)$(RMDIR) ext 2> /dev/null || true
-
-clean-extout:
-	-$(Q)$(RMDIRS) $(EXTOUT) 2> /dev/null || true
-
-clean-enc distclean-enc realclean-enc:
-	@test -f "$(ENC_MK)" || exit 0; \
-	echo $(@:-enc=ing) encodings; \
-	exec $(MAKE) -f $(ENC_MK) $(MFLAGS) $(@:-enc=)
-
-clean-rdoc distclean-rdoc realclean-rdoc:
-	@echo $(@:-rdoc=ing) rdoc
-	$(Q)$(RMALL) $(RDOCOUT)
-clean-capi distclean-capi realclean-capi:
-	@echo $(@:-capi=ing) capi
-	$(Q)$(RMALL) $(CAPIOUT)
-
-clean-platform:
-	@$(RM) $(PLATFORM_D)
-	-$(Q) $(RMDIR) $(PLATFORM_DIR) 2> /dev/null || true
-
-ext/extinit.$(OBJEXT): ext/extinit.c $(SETUP)
-	$(ECHO) compiling $@
-	$(Q) $(CC) $(CFLAGS) $(XCFLAGS) $(CPPFLAGS) $(COUTFLAG)$@ -c ext/extinit.c
-
-enc/encinit.$(OBJEXT): enc/encinit.c $(SETUP)
-
-up::
-	@$(CHDIR) "$(srcdir)" && LC_TIME=C exec $(VCSUP)
-
-up::
-	-$(Q)$(MAKE) $(MFLAGS) after-update
-
-after-update:: update-config_files
-
-update-mspec:
-	@$(CHDIR) $(srcdir); \
-	if [ -d spec/mspec ]; then \
-	  cd spec/mspec; \
-	  echo updating mspec ...; \
-	  exec git pull; \
-	else \
-	  echo retrieving mspec ...; \
-	  exec git clone $(MSPEC_GIT_URL) spec/mspec; \
-	fi
-
-update-rubyspec: update-mspec
-	@$(CHDIR) $(srcdir); \
-	if [ -d spec/rubyspec ]; then \
-	  cd spec/rubyspec; \
-	  echo updating rubyspec ...; \
-	  exec git pull; \
-	else \
-	  echo retrieving rubyspec ...; \
-	  exec git clone $(RUBYSPEC_GIT_URL) spec/rubyspec; \
-	fi
-
-test-rubyspec-precheck:
-	@if [ ! -d $(srcdir)/spec/rubyspec ]; then echo No rubyspec here.  make update-rubyspec first.; exit 1; fi
-
-INSNS	= opt_sc.inc optinsn.inc optunifs.inc insns.inc insns_info.inc \
-	  vmtc.inc vm.inc
-
-$(INSNS): $(srcdir)/insns.def vm_opts.h \
-	  $(srcdir)/defs/opt_operand.def $(srcdir)/defs/opt_insn_unif.def \
-	  $(srcdir)/tool/instruction.rb $(srcdir)/tool/insns2vm.rb
-	$(ECHO) generating $@
-	$(Q) $(BASERUBY) -Ku $(srcdir)/tool/insns2vm.rb $(INSNS2VMOPT) $@
-
-loadpath: verconf.h
-	@$(CPP) $(XCFLAGS) $(CPPFLAGS) $(srcdir)/loadpath.c | \
-	sed -e '1,/^const char ruby_initial_load_paths/d;/;/,$$d' \
-	    -e '/^ /!d;s/ *"\\0"$$//;s/" *"//g'
diff --git a/NEWS b/NEWS
deleted file mode 100644
index 0c70db07bc..0000000000
--- a/NEWS
+++ /dev/null
@@ -1,27 +0,0 @@
-# -*- rdoc -*-
-
-= NEWS for Ruby 2.2.0
-
-This document is a list of user visible feature changes made between
-releases except for bug fixes.
-
-Note that each entry is kept so brief that no reason behind or
-reference information is supplied with.  For a full list of changes
-with all sufficient information, see the ChangeLog file.
-
-== Changes since the 2.1.0 release
-
-=== Language changes
-
-=== Core classes updates (outstanding ones only)
-
-=== Core classes compatibility issues (excluding feature bug fixes)
-
-=== Stdlib updates (outstanding ones only)
-
-=== Stdlib compatibility issues (excluding feature bug fixes)
-
-=== Built-in global variables compatibility issues
-
-=== C API updates
-
diff --git a/NEWS.md b/NEWS.md
new file mode 100644
index 0000000000..f6c3c6fc97
--- /dev/null
+++ b/NEWS.md
@@ -0,0 +1,820 @@
+# NEWS for Ruby 3.2.0
+
+This document is a list of user-visible feature changes
+since the **3.1.0** release, except for bug fixes.
+
+Note that each entry is kept to a minimum, see links for details.
+
+## Language changes
+
+* Anonymous rest and keyword rest arguments can now be passed as
+  arguments, instead of just used in method parameters.
+  [[Feature #18351]]
+
+    ```ruby
+    def foo(*)
+      bar(*)
+    end
+    def baz(**)
+      quux(**)
+    end
+    ```
+
+* A proc that accepts a single positional argument and keywords will
+  no longer autosplat. [[Bug #18633]]
+
+    ```ruby
+    proc{|a, **k| a}.call([1, 2])
+    # Ruby 3.1 and before
+    # => 1
+    # Ruby 3.2 and after
+    # => [1, 2]
+    ```
+
+* Constant assignment evaluation order for constants set on explicit
+  objects has been made consistent with single attribute assignment
+  evaluation order. With this code:
+
+    ```ruby
+    foo::BAR = baz
+    ```
+
+    `foo` is now called before `baz`. Similarly, for multiple assignments
+    to constants,  left-to-right evaluation order is used. With this
+    code:
+
+    ```ruby
+    foo1::BAR1, foo2::BAR2 = baz1, baz2
+    ```
+
+    The following evaluation order is now used:
+
+    1. `foo1`
+    2. `foo2`
+    3. `baz1`
+    4. `baz2`
+
+    [[Bug #15928]]
+
+* "Find pattern" is no longer experimental.
+  [[Feature #18585]]
+
+* Methods taking a rest parameter (like `*args`) and wishing to delegate keyword
+  arguments through `foo(*args)` must now be marked with `ruby2_keywords`
+  (if not already the case). In other words, all methods wishing to delegate
+  keyword arguments through `*args` must now be marked with `ruby2_keywords`,
+  with no exception. This will make it easier to transition to other ways of
+  delegation once a library can require Ruby 3+. Previously, the `ruby2_keywords`
+  flag was kept if the receiving method took `*args`, but this was a bug and an
+  inconsistency. A good technique to find the potentially-missing `ruby2_keywords`
+  is to run the test suite, for where it fails find the last method which must
+  receive keyword arguments, use `puts nil, caller, nil` there, and check each
+  method/block on the call chain which must delegate keywords is correctly marked
+  as `ruby2_keywords`. [[Bug #18625]] [[Bug #16466]]
+
+    ```ruby
+    def target(**kw)
+    end
+
+    # Accidentally worked without ruby2_keywords in Ruby 2.7-3.1, ruby2_keywords
+    # needed in 3.2+. Just like (*args, **kwargs) or (...) would be needed on
+    # both #foo and #bar when migrating away from ruby2_keywords.
+    ruby2_keywords def bar(*args)
+      target(*args)
+    end
+
+    ruby2_keywords def foo(*args)
+      bar(*args)
+    end
+
+    foo(k: 1)
+    ```
+
+## Core classes updates
+
+Note: We're only listing outstanding class updates.
+
+* Fiber
+
+    * Introduce Fiber.[] and Fiber.[]= for inheritable fiber storage.
+      Introduce Fiber#storage and Fiber#storage= (experimental) for
+      getting and resetting the current storage.  Introduce
+      `Fiber.new(storage:)` for setting the storage when creating a
+      fiber. [[Feature #19078]]
+
+        Existing Thread and Fiber local variables can be tricky to use.
+        Thread-local variables are shared between all fibers, making it
+        hard to isolate, while Fiber-local variables can be hard to
+        share.  It is often desirable to define unit of execution
+        ("execution context") such that some state is shared between all
+        fibers and threads created in that context.  This is what Fiber
+        storage provides.
+
+        ```ruby
+        def log(message)
+          puts "#{Fiber[:request_id]}: #{message}"
+        end
+
+        def handle_requests
+          while request = read_request
+            Fiber.schedule do
+              Fiber[:request_id] = SecureRandom.uuid
+
+              request.messages.each do |message|
+                Fiber.schedule do
+                  log("Handling #{message}") # Log includes inherited request_id.
+                end
+              end
+            end
+          end
+        end
+        ```
+
+        You should generally consider Fiber storage for any state which
+        you want to be shared implicitly between all fibers and threads
+        created in a given context, e.g. a connection pool, a request
+        id, a logger level, environment variables, configuration, etc.
+
+* Fiber::Scheduler
+
+    * Introduce `Fiber::Scheduler#io_select` for non-blocking IO.select.
+      [[Feature #19060]]
+
+* IO
+
+    * Introduce IO#timeout= and IO#timeout which can cause
+      IO::TimeoutError to be raised if a blocking operation exceeds the
+      specified timeout. [[Feature #18630]]
+
+        ```ruby
+        STDIN.timeout = 1
+        STDIN.read # => Blocking operation timed out! (IO::TimeoutError)
+        ```
+
+    * Introduce `IO.new(..., path:)` and promote `File#path` to `IO#path`.
+      [[Feature #19036]]
+
+* Class
+
+    * Class#attached_object, which returns the object for which
+      the receiver is the singleton class. Raises TypeError if the
+      receiver is not a singleton class.
+      [[Feature #12084]]
+
+        ```ruby
+        class Foo; end
+
+        Foo.singleton_class.attached_object        #=> Foo
+        Foo.new.singleton_class.attached_object    #=> #<Foo:0x000000010491a370>
+        Foo.attached_object                        #=> TypeError: `Foo' is not a singleton class
+        nil.singleton_class.attached_object        #=> TypeError: `NilClass' is not a singleton class
+        ```
+
+* Data
+
+    * New core class to represent simple immutable value object. The class is
+      similar to Struct and partially shares an implementation, but has more
+      lean and strict API. [[Feature #16122]]
+
+        ```ruby
+        Measure = Data.define(:amount, :unit)
+        distance = Measure.new(100, 'km')            #=> #<data Measure amount=100, unit="km">
+        weight = Measure.new(amount: 50, unit: 'kg') #=> #<data Measure amount=50, unit="kg">
+        weight.with(amount: 40)                      #=> #<data Measure amount=40, unit="kg">
+        weight.amount                                #=> 50
+        weight.amount = 40                           #=> NoMethodError: undefined method `amount='
+        ```
+
+* Encoding
+
+    * Encoding#replicate has been deprecated and will be removed in 3.3. [[Feature #18949]]
+    * The dummy `Encoding::UTF_16` and `Encoding::UTF_32` encodings no longer
+      try to dynamically guess the endian based on a byte order mark.
+      Use `Encoding::UTF_16BE`/`UTF_16LE` and `Encoding::UTF_32BE`/`UTF_32LE` instead.
+      This change speeds up getting the encoding of a String. [[Feature #18949]]
+    * Limit maximum encoding set size by 256.
+      If exceeding maximum size, `EncodingError` will be raised. [[Feature #18949]]
+
+* Enumerator
+
+    * Enumerator.product has been added.  Enumerator::Product is the implementation. [[Feature #18685]]
+
+* Exception
+
+    * Exception#detailed_message has been added.
+      The default error printer calls this method on the Exception object
+      instead of #message. [[Feature #18564]]
+
+* Hash
+
+    * Hash#shift now always returns nil if the hash is
+      empty, instead of returning the default value or
+      calling the default proc. [[Bug #16908]]
+
+* Integer
+
+    * Integer#ceildiv has been added. [[Feature #18809]]
+
+* Kernel
+
+    * Kernel#binding raises RuntimeError if called from a non-Ruby frame
+      (such as a method defined in C). [[Bug #18487]]
+
+* MatchData
+
+    * MatchData#byteoffset has been added. [[Feature #13110]]
+    * MatchData#deconstruct has been added. [[Feature #18821]]
+    * MatchData#deconstruct_keys has been added. [[Feature #18821]]
+
+* Module
+
+    * Module.used_refinements has been added. [[Feature #14332]]
+    * Module#refinements has been added. [[Feature #12737]]
+    * Module#const_added has been added. [[Feature #17881]]
+    * Module#undefined_instance_methods has been added. [[Feature #12655]]
+
+* Proc
+
+    * Proc#dup returns an instance of subclass. [[Bug #17545]]
+    * Proc#parameters now accepts lambda keyword. [[Feature #15357]]
+
+* Process
+    * Added `RLIMIT_NPTS` constant to FreeBSD platform
+
+* Regexp
+
+    * The cache-based optimization is introduced.
+      Many (but not all) Regexp matching is now in linear time, which
+      will prevent regular expression denial of service (ReDoS)
+      vulnerability. [[Feature #19104]]
+
+    * Regexp.linear_time? is introduced. [[Feature #19194]]
+
+    * Regexp.new now supports passing the regexp flags not only as an Integer,
+      but also as a String.  Unknown flags raise ArgumentError.
+      Otherwise, anything other than `true`, `false`, `nil` or Integer will be warned.
+      [[Feature #18788]]
+
+    * Regexp.timeout= has been added. Also, Regexp.new new supports timeout keyword.
+      See [[Feature #17837]]
+
+* Refinement
+
+    * Refinement#refined_class has been added. [[Feature #12737]]
+
+* RubyVM::AbstractSyntaxTree
+
+    * Add `error_tolerant` option for `parse`, `parse_file` and `of`. [[Feature #19013]]
+      With this option
+
+        1. SyntaxError is suppressed
+        2. AST is returned for invalid input
+        3. `end` is complemented when a parser reaches to the end of input but `end` is insufficient
+        4. `end` is treated as keyword based on indent
+
+        ```ruby
+        # Without error_tolerant option
+        root = RubyVM::AbstractSyntaxTree.parse(<<~RUBY)
+        def m
+          a = 10
+          if
+        end
+        RUBY
+        # => <internal:ast>:33:in `parse': syntax error, unexpected `end' (SyntaxError)
+
+        # With error_tolerant option
+        root = RubyVM::AbstractSyntaxTree.parse(<<~RUBY, error_tolerant: true)
+        def m
+          a = 10
+          if
+        end
+        RUBY
+        p root # => #<RubyVM::AbstractSyntaxTree::Node:SCOPE@1:0-4:3>
+
+        # `end` is treated as keyword based on indent
+        root = RubyVM::AbstractSyntaxTree.parse(<<~RUBY, error_tolerant: true)
+        module Z
+          class Foo
+            foo.
+          end
+
+          def bar
+          end
+        end
+        RUBY
+        p root.children[-1].children[-1].children[-1].children[-2..-1]
+        # => [#<RubyVM::AbstractSyntaxTree::Node:CLASS@2:2-4:5>, #<RubyVM::AbstractSyntaxTree::Node:DEFN@6:2-7:5>]
+        ```
+
+    * Add `keep_tokens` option for `parse`, `parse_file` and `of`. Add `#tokens` and `#all_tokens`
+      for RubyVM::AbstractSyntaxTree::Node [[Feature #19070]]
+
+        ```ruby
+        root = RubyVM::AbstractSyntaxTree.parse("x = 1 + 2", keep_tokens: true)
+        root.tokens # => [[0, :tIDENTIFIER, "x", [1, 0, 1, 1]], [1, :tSP, " ", [1, 1, 1, 2]], ...]
+        root.tokens.map{_1[2]}.join # => "x = 1 + 2"
+        ```
+
+* Set
+
+    * Set is now available as a built-in class without the need for `require "set"`. [[Feature #16989]]
+      It is currently autoloaded via the Set constant or a call to Enumerable#to_set.
+
+* String
+
+    * String#byteindex and String#byterindex have been added. [[Feature #13110]]
+    * Update Unicode to Version 15.0.0 and Emoji Version 15.0. [[Feature #18639]]
+      (also applies to Regexp)
+    * String#bytesplice has been added.  [[Feature #18598]]
+    * String#dedup has been added as an alias to String#-@.  [[Feature #18595]]
+
+* Struct
+
+    * A Struct class can also be initialized with keyword arguments
+      without `keyword_init: true` on Struct.new [[Feature #16806]]
+
+        ```ruby
+        Post = Struct.new(:id, :name)
+        Post.new(1, "hello") #=> #<struct Post id=1, name="hello">
+        # From Ruby 3.2, the following code also works without keyword_init: true.
+        Post.new(id: 1, name: "hello") #=> #<struct Post id=1, name="hello">
+        ```
+
+* Thread
+
+    * Thread.each_caller_location is added. [[Feature #16663]]
+
+* Thread::Queue
+
+    * Thread::Queue#pop(timeout: sec) is added. [[Feature #18774]]
+
+* Thread::SizedQueue
+
+    * Thread::SizedQueue#pop(timeout: sec) is added. [[Feature #18774]]
+    * Thread::SizedQueue#push(timeout: sec) is added. [[Feature #18944]]
+
+* Time
+
+    * Time#deconstruct_keys is added, allowing to use Time instances
+      in pattern-matching expressions [[Feature #19071]]
+
+    * Time.new now can parse a string like generated by Time#inspect
+      and return a Time instance based on the given argument.
+      [[Feature #18033]]
+
+* SyntaxError
+    * SyntaxError#path has been added.  [[Feature #19138]]
+
+* TracePoint
+
+    * TracePoint#binding now returns `nil` for `c_call`/`c_return` TracePoints.
+      [[Bug #18487]]
+    * TracePoint#enable `target_thread` keyword argument now defaults to the
+      current thread if a block is given and `target` and `target_line` keyword
+      arguments are not passed. [[Bug #16889]]
+
+* UnboundMethod
+
+    * `UnboundMethod#==` returns `true` if the actual method is same. For example,
+      `String.instance_method(:object_id) == Array.instance_method(:object_id)`
+      returns `true`. [[Feature #18798]]
+
+    * `UnboundMethod#inspect` does not show the receiver of `instance_method`.
+      For example `String.instance_method(:object_id).inspect` returns
+      `"#<UnboundMethod: Kernel#object_id()>"`
+      (was `"#<UnboundMethod: String(Kernel)#object_id()>"`).
+
+* GC
+
+    * Expose `need_major_gc` via `GC.latest_gc_info`. [GH-6791]
+
+* ObjectSpace
+
+    * `ObjectSpace.dump_all` dump shapes as well. [GH-6868]
+
+## Stdlib updates
+
+* Bundler
+
+    * Bundler now uses [PubGrub] resolver instead of [Molinillo] for performance improvement.
+    * Add --ext=rust support to bundle gem for creating simple gems with Rust extensions.
+      [[GH-rubygems-6149]]
+    * Make cloning git repos faster [[GH-rubygems-4475]]
+
+* RubyGems
+
+    * Add mswin support for cargo builder. [[GH-rubygems-6167]]
+
+* CGI
+
+    * `CGI.escapeURIComponent` and `CGI.unescapeURIComponent` are added.
+      [[Feature #18822]]
+
+* Coverage
+
+    * `Coverage.setup` now accepts `eval: true`. By this, `eval` and related methods are
+      able to generate code coverage. [[Feature #19008]]
+
+    * `Coverage.supported?(mode)` enables detection of what coverage modes are
+      supported. [[Feature #19026]]
+
+* Date
+
+    * Added `Date#deconstruct_keys` and `DateTime#deconstruct_keys` same as [[Feature #19071]]
+
+* ERB
+
+    * `ERB::Util.html_escape` is made faster than `CGI.escapeHTML`.
+        * It no longer allocates a String object when no character needs to be escaped.
+        * It skips calling `#to_s` method when an argument is already a String.
+        * `ERB::Escape.html_escape` is added as an alias to `ERB::Util.html_escape`,
+          which has not been monkey-patched by Rails.
+    * `ERB::Util.url_encode` is made faster using `CGI.escapeURIComponent`.
+    * `-S` option is removed from `erb` command.
+
+* FileUtils
+
+    * Add FileUtils.ln_sr method and `relative:` option to FileUtils.ln_s.
+      [[Feature #18925]]
+
+* IRB
+
+    * debug.gem integration commands have been added: `debug`, `break`, `catch`,
+      `next`, `delete`, `step`, `continue`, `finish`, `backtrace`, `info`
+        * They work even if you don't have `gem "debug"` in your Gemfile.
+        * See also: [What's new in Ruby 3.2's IRB?](https://st0012.dev/whats-new-in-ruby-3-2-irb)
+    * More Pry-like commands and features have been added.
+        * `edit` and `show_cmds` (like Pry's `help`) are added.
+        * `ls` takes `-g` or `-G` option to filter out outputs.
+        * `show_source` is aliased from `$` and accepts unquoted inputs.
+        * `whereami` is aliased from `@`.
+
+* Net::Protocol
+
+    * Improve `Net::BufferedIO` performance. [[GH-net-protocol-14]]
+
+* Pathname
+
+    * Added `Pathname#lutime`. [[GH-pathname-20]]
+
+* Socket
+
+    * Added the following constants for supported platforms.
+        * `SO_INCOMING_CPU`
+        * `SO_INCOMING_NAPI_ID`
+        * `SO_RTABLE`
+        * `SO_SETFIB`
+        * `SO_USER_COOKIE`
+        * `TCP_KEEPALIVE`
+        * `TCP_CONNECTION_INFO`
+
+* SyntaxSuggest
+
+    * The feature of `syntax_suggest` formerly `dead_end` is integrated in Ruby.
+      [[Feature #18159]]
+
+* UNIXSocket
+
+    * Add support for UNIXSocket on Windows. Emulate anonymous sockets. Add
+      support for File.socket? and File::Stat#socket? where possible.
+      [[Feature #19135]]
+
+*   The following default gems are updated.
+
+    * RubyGems 3.4.1
+    * abbrev 0.1.1
+    * benchmark 0.2.1
+    * bigdecimal 3.1.3
+    * bundler 2.4.1
+    * cgi 0.3.6
+    * csv 3.2.6
+    * date 3.3.3
+    * delegate 0.3.0
+    * did_you_mean 1.6.3
+    * digest 3.1.1
+    * drb 2.1.1
+    * english 0.7.2
+    * erb 4.0.2
+    * error_highlight 0.5.1
+    * etc 1.4.2
+    * fcntl 1.0.2
+    * fiddle 1.1.1
+    * fileutils 1.7.0
+    * forwardable 1.3.3
+    * getoptlong 0.2.0
+    * io-console 0.6.0
+    * io-nonblock 0.2.0
+    * io-wait 0.3.0
+    * ipaddr 1.2.5
+    * irb 1.6.2
+    * json 2.6.3
+    * logger 1.5.3
+    * mutex_m 0.1.2
+    * net-http 0.4.0
+    * net-protocol 0.2.1
+    * nkf 0.1.2
+    * open-uri 0.3.0
+    * open3 0.1.2
+    * openssl 3.1.0
+    * optparse 0.3.1
+    * ostruct 0.5.5
+    * pathname 0.2.1
+    * pp 0.4.0
+    * pstore 0.1.2
+    * psych 5.0.1
+    * racc 1.6.2
+    * rdoc 6.5.0
+    * readline-ext 0.1.5
+    * reline 0.3.2
+    * resolv 0.2.2
+    * resolv-replace 0.1.1
+    * securerandom 0.2.2
+    * set 1.0.3
+    * stringio 3.0.4
+    * strscan 3.0.5
+    * syntax_suggest 1.0.2
+    * syslog 0.1.1
+    * tempfile 0.1.3
+    * time 0.2.1
+    * timeout 0.3.1
+    * tmpdir 0.1.3
+    * tsort 0.1.1
+    * un 0.2.1
+    * uri 0.12.0
+    * weakref 0.1.2
+    * win32ole 1.8.9
+    * yaml 0.2.1
+    * zlib 3.0.0
+
+*   The following bundled gems are updated.
+
+    * minitest 5.16.3
+    * power_assert 2.0.3
+    * test-unit 3.5.7
+    * net-ftp 0.2.0
+    * net-imap 0.3.4
+    * net-pop 0.1.2
+    * net-smtp 0.3.3
+    * rbs 2.8.2
+    * typeprof 0.21.3
+    * debug 1.7.1
+
+See GitHub releases like [GitHub Releases of Logger](https://github.com/ruby/logger/releases) or changelog for details of the default gems or bundled gems.
+
+## Supported platforms
+
+* WebAssembly/WASI is added. See [wasm/README.md] and [ruby.wasm] for more details. [[Feature #18462]]
+
+## Compatibility issues
+
+* `String#to_c` currently treat a sequence of underscores as an end of Complex
+  string. [[Bug #19087]]
+
+* Now `ENV.clone` raises `TypeError` as well as `ENV.dup` [[Bug #17767]]
+
+### Removed constants
+
+The following deprecated constants are removed.
+
+* `Fixnum` and `Bignum` [[Feature #12005]]
+* `Random::DEFAULT` [[Feature #17351]]
+* `Struct::Group`
+* `Struct::Passwd`
+
+### Removed methods
+
+The following deprecated methods are removed.
+
+* `Dir.exists?` [[Feature #17391]]
+* `File.exists?` [[Feature #17391]]
+* `Kernel#=~` [[Feature #15231]]
+* `Kernel#taint`, `Kernel#untaint`, `Kernel#tainted?`
+  [[Feature #16131]]
+* `Kernel#trust`, `Kernel#untrust`, `Kernel#untrusted?`
+  [[Feature #16131]]
+* `Method#public?`, `Method#private?`, `Method#protected?`,
+  `UnboundMethod#public?`, `UnboundMethod#private?`, `UnboundMethod#protected?`
+  [[Bug #18729]] [[Bug #18751]] [[Bug #18435]]
+
+### Source code incompatibility of extension libraries
+
+* Extension libraries provide PRNG, subclasses of Random, need updates.
+  See [PRNG update] below for more information. [[Bug #19100]]
+
+### Error printer
+
+* Ruby no longer escapes control characters and backslashes in an
+  error message. [[Feature #18367]]
+
+### Constant lookup when defining a class/module
+
+* When defining a class/module directly under the Object class by class/module
+  statement, if there is already a class/module defined by `Module#include`
+  with the same name, the statement was handled as "open class" in Ruby 3.1 or before.
+  Since Ruby 3.2, a new class is defined instead. [[Feature #18832]]
+
+## Stdlib compatibility issues
+
+* Psych no longer bundles libyaml sources.
+  And also Fiddle no longer bundles libffi sources.
+  Users need to install the libyaml/libffi library themselves via the package
+  manager like apt, yum, brew, etc.
+
+    Psych and fiddle supported the static build with specific version of libyaml
+    and libffi sources. You can build psych with libyaml-0.2.5 like this.
+
+    ```bash
+    $ ./configure --with-libyaml-source-dir=/path/to/libyaml-0.2.5
+    ```
+
+    And you can build fiddle with libffi-3.4.4 like this.
+
+    ```bash
+    $ ./configure --with-libffi-source-dir=/path/to/libffi-3.4.4
+    ```
+
+    [[Feature #18571]]
+
+* Check cookie name/path/domain characters in `CGI::Cookie`. [[CVE-2021-33621]]
+
+* `URI.parse` return empty string in host instead of nil. [[sec-156615]]
+
+## C API updates
+
+### Updated C APIs
+
+The following APIs are updated.
+
+* PRNG update
+
+    `rb_random_interface_t` in ruby/random.h updated and versioned.
+    Extension libraries which use this interface and built for older
+    versions need to rebuild with adding `init_int32` function.
+
+### Added C APIs
+
+* `VALUE rb_hash_new_capa(long capa)` was added to created hashes with the desired capacity.
+* `rb_internal_thread_add_event_hook` and `rb_internal_thread_add_event_hook` were added to instrument threads scheduling.
+  The following events are available:
+    * `RUBY_INTERNAL_THREAD_EVENT_STARTED`
+    * `RUBY_INTERNAL_THREAD_EVENT_READY`
+    * `RUBY_INTERNAL_THREAD_EVENT_RESUMED`
+    * `RUBY_INTERNAL_THREAD_EVENT_SUSPENDED`
+    * `RUBY_INTERNAL_THREAD_EVENT_EXITED`
+* `rb_debug_inspector_current_depth` and `rb_debug_inspector_frame_depth` are added for debuggers.
+
+### Removed C APIs
+
+The following deprecated APIs are removed.
+
+* `rb_cData` variable.
+* "taintedness" and "trustedness" functions. [[Feature #16131]]
+
+## Implementation improvements
+
+* Fixed several race conditions in Kernel#autoload. [[Bug #18782]]
+* Cache invalidation for expressions referencing constants is now
+  more fine-grained. `RubyVM.stat(:global_constant_state)` was
+  removed because it was closely tied to the previous caching scheme
+  where setting any constant invalidates all caches in the system.
+  New keys, `:constant_cache_invalidations` and `:constant_cache_misses`,
+  were introduced to help with use cases for `:global_constant_state`.
+  [[Feature #18589]]
+* The cache-based optimization for Regexp matching is introduced.
+  [[Feature #19104]]
+* [Variable Width Allocation](https://shopify.engineering/ruby-variable-width-allocation)
+  is now enabled by default. [[Feature #18239]]
+* Added a new instance variable caching mechanism, called object shapes, which
+  improves inline cache hits for most objects and allows us to generate very
+  efficient JIT code. Objects whose instance variables are defined in a
+  consistent order will see the most performance benefits.
+  [[Feature #18776]]
+* Speed up marking instruction sequences by using a bitmap to find "markable"
+  objects.  This change results in faster major collections.
+  [[Feature #18875]]
+
+## JIT
+
+### YJIT
+
+* YJIT is no longer experimental
+    * Has been tested on production workloads for over a year and proven to be quite stable.
+* YJIT now supports both x86-64 and arm64/aarch64 CPUs on Linux, MacOS, BSD and other UNIX platforms.
+    * This release brings support for Mac M1/M2, AWS Graviton and Raspberry Pi 4.
+* Building YJIT now requires Rust 1.58.0+. [[Feature #18481]]
+    * In order to ensure that CRuby is built with YJIT, please install `rustc` >= 1.58.0
+      before running `./configure`
+    * Please reach out to the YJIT team should you run into any issues.
+* Physical memory for JIT code is lazily allocated. Unlike Ruby 3.1,
+  the RSS of a Ruby process is minimized because virtual memory pages
+  allocated by `--yjit-exec-mem-size` will not be mapped to physical
+  memory pages until actually utilized by JIT code.
+* Introduce Code GC that frees all code pages when the memory consumption
+  by JIT code reaches `--yjit-exec-mem-size`.
+    * `RubyVM::YJIT.runtime_stats` returns Code GC metrics in addition to
+      existing `inline_code_size` and `outlined_code_size` keys:
+      `code_gc_count`, `live_page_count`, `freed_page_count`, and `freed_code_size`.
+* Most of the statistics produced by `RubyVM::YJIT.runtime_stats` are now available in release builds.
+    * Simply run ruby with `--yjit-stats` to compute and dump stats (incurs some run-time overhead).
+* YJIT is now optimized to take advantage of object shapes. [[Feature #18776]]
+* Take advantage of finer-grained constant invalidation to invalidate less code when defining new constants. [[Feature #18589]]
+* The default `--yjit-exec-mem-size` is changed to 64 (MiB).
+* The default `--yjit-call-threshold` is changed to 30.
+
+### MJIT
+
+* The MJIT compiler is re-implemented in Ruby as `ruby_vm/mjit/compiler`.
+* MJIT compiler is executed under a forked Ruby process instead of
+  doing it in a native thread called MJIT worker. [[Feature #18968]]
+    * As a result, Microsoft Visual Studio (MSWIN) is no longer supported.
+* MinGW is no longer supported. [[Feature #18824]]
+* Rename `--mjit-min-calls` to `--mjit-call-threshold`.
+* Change default `--mjit-max-cache` back from 10000 to 100.
+
+[Feature #12005]:     https://bugs.ruby-lang.org/issues/12005
+[Feature #12084]:     https://bugs.ruby-lang.org/issues/12084
+[Feature #12655]:     https://bugs.ruby-lang.org/issues/12655
+[Feature #12737]:     https://bugs.ruby-lang.org/issues/12737
+[Feature #13110]:     https://bugs.ruby-lang.org/issues/13110
+[Feature #14332]:     https://bugs.ruby-lang.org/issues/14332
+[Feature #15231]:     https://bugs.ruby-lang.org/issues/15231
+[Feature #15357]:     https://bugs.ruby-lang.org/issues/15357
+[Bug #15928]:         https://bugs.ruby-lang.org/issues/15928
+[Feature #16122]:     https://bugs.ruby-lang.org/issues/16122
+[Feature #16131]:     https://bugs.ruby-lang.org/issues/16131
+[Bug #16466]:         https://bugs.ruby-lang.org/issues/16466
+[Feature #16663]:     https://bugs.ruby-lang.org/issues/16663
+[Feature #16806]:     https://bugs.ruby-lang.org/issues/16806
+[Bug #16889]:         https://bugs.ruby-lang.org/issues/16889
+[Bug #16908]:         https://bugs.ruby-lang.org/issues/16908
+[Feature #16989]:     https://bugs.ruby-lang.org/issues/16989
+[Feature #17351]:     https://bugs.ruby-lang.org/issues/17351
+[Feature #17391]:     https://bugs.ruby-lang.org/issues/17391
+[Bug #17545]:         https://bugs.ruby-lang.org/issues/17545
+[Bug #17767]:         https://bugs.ruby-lang.org/issues/17767
+[Feature #17837]:     https://bugs.ruby-lang.org/issues/17837
+[Feature #17881]:     https://bugs.ruby-lang.org/issues/17881
+[Feature #18033]:     https://bugs.ruby-lang.org/issues/18033
+[Feature #18159]:     https://bugs.ruby-lang.org/issues/18159
+[Feature #18239]:     https://bugs.ruby-lang.org/issues/18239#note-17
+[Feature #18351]:     https://bugs.ruby-lang.org/issues/18351
+[Feature #18367]:     https://bugs.ruby-lang.org/issues/18367
+[Bug #18435]:         https://bugs.ruby-lang.org/issues/18435
+[Feature #18462]:     https://bugs.ruby-lang.org/issues/18462
+[Feature #18481]:     https://bugs.ruby-lang.org/issues/18481
+[Bug #18487]:         https://bugs.ruby-lang.org/issues/18487
+[Feature #18564]:     https://bugs.ruby-lang.org/issues/18564
+[Feature #18571]:     https://bugs.ruby-lang.org/issues/18571
+[Feature #18585]:     https://bugs.ruby-lang.org/issues/18585
+[Feature #18589]:     https://bugs.ruby-lang.org/issues/18589
+[Feature #18595]:     https://bugs.ruby-lang.org/issues/18595
+[Feature #18598]:     https://bugs.ruby-lang.org/issues/18598
+[Bug #18625]:         https://bugs.ruby-lang.org/issues/18625
+[Feature #18630]:     https://bugs.ruby-lang.org/issues/18630
+[Bug #18633]:         https://bugs.ruby-lang.org/issues/18633
+[Feature #18639]:     https://bugs.ruby-lang.org/issues/18639
+[Feature #18685]:     https://bugs.ruby-lang.org/issues/18685
+[Bug #18729]:         https://bugs.ruby-lang.org/issues/18729
+[Bug #18751]:         https://bugs.ruby-lang.org/issues/18751
+[Feature #18774]:     https://bugs.ruby-lang.org/issues/18774
+[Feature #18776]:     https://bugs.ruby-lang.org/issues/18776
+[Bug #18782]:         https://bugs.ruby-lang.org/issues/18782
+[Feature #18788]:     https://bugs.ruby-lang.org/issues/18788
+[Feature #18798]:     https://bugs.ruby-lang.org/issues/18798
+[Feature #18809]:     https://bugs.ruby-lang.org/issues/18809
+[Feature #18821]:     https://bugs.ruby-lang.org/issues/18821
+[Feature #18822]:     https://bugs.ruby-lang.org/issues/18822
+[Feature #18824]:     https://bugs.ruby-lang.org/issues/18824
+[Feature #18832]:     https://bugs.ruby-lang.org/issues/18832
+[Feature #18875]:     https://bugs.ruby-lang.org/issues/18875
+[Feature #18925]:     https://bugs.ruby-lang.org/issues/18925
+[Feature #18944]:     https://bugs.ruby-lang.org/issues/18944
+[Feature #18949]:     https://bugs.ruby-lang.org/issues/18949
+[Feature #18968]:     https://bugs.ruby-lang.org/issues/18968
+[Feature #19008]:     https://bugs.ruby-lang.org/issues/19008
+[Feature #19013]:     https://bugs.ruby-lang.org/issues/19013
+[Feature #19026]:     https://bugs.ruby-lang.org/issues/19026
+[Feature #19036]:     https://bugs.ruby-lang.org/issues/19036
+[Feature #19060]:     https://bugs.ruby-lang.org/issues/19060
+[Feature #19070]:     https://bugs.ruby-lang.org/issues/19070
+[Feature #19071]:     https://bugs.ruby-lang.org/issues/19071
+[Feature #19078]:     https://bugs.ruby-lang.org/issues/19078
+[Bug #19087]:         https://bugs.ruby-lang.org/issues/19087
+[Bug #19100]:         https://bugs.ruby-lang.org/issues/19100
+[Feature #19104]:     https://bugs.ruby-lang.org/issues/19104
+[Feature #19135]:     https://bugs.ruby-lang.org/issues/19135
+[Feature #19138]:     https://bugs.ruby-lang.org/issues/19138
+[Feature #19194]:     https://bugs.ruby-lang.org/issues/19194
+[Molinillo]:          https://github.com/CocoaPods/Molinillo
+[PubGrub]:            https://github.com/jhawthorn/pub_grub
+[GH-net-protocol-14]: https://github.com/ruby/net-protocol/pull/14
+[GH-pathname-20]:     https://github.com/ruby/pathname/pull/20
+[GH-6791]:            https://github.com/ruby/ruby/pull/6791
+[GH-6868]:            https://github.com/ruby/ruby/pull/6868
+[GH-rubygems-4475]:   https://github.com/rubygems/rubygems/pull/4475
+[GH-rubygems-6149]:   https://github.com/rubygems/rubygems/pull/6149
+[GH-rubygems-6167]:   https://github.com/rubygems/rubygems/pull/6167
+[sec-156615]:         https://hackerone.com/reports/156615
+[CVE-2021-33621]:     https://www.ruby-lang.org/en/news/2022/11/22/http-response-splitting-in-cgi-cve-2021-33621/
+[wasm/README.md]:     https://github.com/ruby/ruby/blob/master/wasm/README.md
+[ruby.wasm]:          https://github.com/ruby/ruby.wasm
diff --git a/README b/README
deleted file mode 100644
index 3ffe3553a8..0000000000
--- a/README
+++ /dev/null
@@ -1,166 +0,0 @@
-= What's Ruby
-
-Ruby is the interpreted scripting language for quick and
-easy object-oriented programming.  It has many features to
-process text files and to do system management tasks (as in
-Perl).  It is simple, straight-forward, and extensible.
-
-
-== Features of Ruby
-
-*   Simple Syntax
-*   *Normal* Object-Oriented features(ex. class, method calls)
-*   *Advanced* Object-Oriented features(ex. Mix-in, Singleton-method)
-*   Operator Overloading
-*   Exception Handling
-*   Iterators and Closures
-*   Garbage Collection
-*   Dynamic Loading of Object files(on some architecture)
-*   Highly Portable (works on many Unix-like/POSIX compatible platforms
-    as well as Windows, Mac OS X, BeOS etc.)
-    cf. http://bugs.ruby-lang.org/projects/ruby-trunk/wiki/SupportedPlatforms
-
-
-== How to get Ruby
-
-For a complete list of ways to install Ruby, including using third party
-tools like rvm, see:
-
-http://www.ruby-lang.org/en/downloads/
-
-The Ruby distribution files can be found in the following FTP site:
-
-ftp://ftp.ruby-lang.org/pub/ruby/
-
-The trunk of the Ruby source tree can be checked out with the
-following command:
-
-  $ svn co http://svn.ruby-lang.org/repos/ruby/trunk/ ruby
-
-Or if you are using git then use the following command:
-
-  $ git clone git://github.com/ruby/ruby.git
-
-There are some other branches under development.  Try the following
-command and see the list of branches:
-
-  $ svn ls http://svn.ruby-lang.org/repos/ruby/branches/
-
-Or if you are using git then use the following command:
-
-  $ git ls-remote git://github.com/ruby/ruby.git
-
-== Ruby home-page
-
-The URL of the Ruby home-page is:
-
-http://www.ruby-lang.org/
-
-
-== Mailing list
-
-There is a mailing list to talk about Ruby.
-To subscribe this list, please send the following phrase
-
-        subscribe YourFirstName YourFamilyName
-e.g.
-        subscribe Joseph Smith
-
-in the mail body (not subject) to the address <mailto:ruby-talk-ctl@ruby-lang.org>.
-
-
-== How to compile and install
-
-This is what you need to do to compile and install Ruby:
-
-0.   If you want to use Microsoft Visual C++ to compile ruby,
-     read win32/README.win32 instead of this document.
-
-1.   If +./configure+ does not exist or is older than configure.in,
-     run autoconf to (re)generate configure.
-
-2.   Run +./configure+, which will generate config.h and Makefile.
-
-     Some C compiler flags may be added by default depending on your
-     environment.  Specify <tt>optflags=..</tt> and <tt>warnflags=..</tt> as
-     necessary to override them.
-
-3.   Edit +defines.h+ if you need. Usually this step will not be needed.
-
-4.   Remove comment mark(<tt>#</tt>) before the module names from +ext/Setup+
-     (or add module names if not present), if you want to link modules
-     statically.
-
-     If you don't want to compile non static extension modules
-     (probably on architectures which does not allow dynamic loading),
-     remove comment mark from the line "<tt>#option nodynamic</tt>" in
-     +ext/Setup+.
-
-     Usually this step will not be needed.
-
-5.   Run +make+.
-
-6.   Optionally, run '<tt>make check</tt>' to check whether the compiled Ruby
-     interpreter works well. If you see the message "<tt>check succeeded</tt>",
-     your ruby works as it should (hopefully).
-
-7.   Run '<tt>make install</tt>'
-
-     This command will create following directories and install files
-     onto them.
-
-     * <tt>${DESTDIR}${prefix}/bin</tt>
-     * <tt>${DESTDIR}${prefix}/include/ruby-${MAJOR}.${MINOR}.${TEENY}</tt>
-     * <tt>${DESTDIR}${prefix}/include/ruby-${MAJOR}.${MINOR}.${TEENY}/${PLATFORM}</tt>
-     * <tt>${DESTDIR}${prefix}/lib</tt>
-     * <tt>${DESTDIR}${prefix}/lib/ruby</tt>
-     * <tt>${DESTDIR}${prefix}/lib/ruby/${MAJOR}.${MINOR}.${TEENY}</tt>
-     * <tt>${DESTDIR}${prefix}/lib/ruby/${MAJOR}.${MINOR}.${TEENY}/${PLATFORM}</tt>
-     * <tt>${DESTDIR}${prefix}/lib/ruby/site_ruby</tt>
-     * <tt>${DESTDIR}${prefix}/lib/ruby/site_ruby/${MAJOR}.${MINOR}.${TEENY}</tt>
-     * <tt>${DESTDIR}${prefix}/lib/ruby/site_ruby/${MAJOR}.${MINOR}.${TEENY}/${PLATFORM}</tt>
-     * <tt>${DESTDIR}${prefix}/lib/ruby/vendor_ruby</tt>
-     * <tt>${DESTDIR}${prefix}/lib/ruby/vendor_ruby/${MAJOR}.${MINOR}.${TEENY}</tt>
-     * <tt>${DESTDIR}${prefix}/lib/ruby/vendor_ruby/${MAJOR}.${MINOR}.${TEENY}/${PLATFORM}</tt>
-     * <tt>${DESTDIR}${prefix}/lib/ruby/gems/${MAJOR}.${MINOR}.${TEENY}</tt>
-     * <tt>${DESTDIR}${prefix}/share/man/man1</tt>
-     * <tt>${DESTDIR}${prefix}/share/ri/${MAJOR}.${MINOR}.${TEENY}/system</tt>
-
-     If Ruby's API version is '_x.y.z_', the <tt>${MAJOR}</tt> is '_x_', the
-     <tt>${MINOR}</tt> is '_y_', and the <tt>${TEENY}</tt> is '_z_'.
-
-     *NOTE*: teeny of the API version may be different from one of
-     Ruby's program version
-
-     You may have to be a super user to install ruby.
-
-If you fail to compile ruby, please send the detailed error report with
-the error log and machine/OS type, to help others.
-
-Some extension libraries may not get compiled because of lack of
-necessary external libraries and/or headers, then you will need to run
-'<tt>make distclean-ext</tt>' to remove old configuration after
-installing them in such case.
-
-== Copying
-
-See the file +COPYING+.
-
-== Feedback
-
-Questions about the Ruby language can be asked on the Ruby-Talk mailing list
-(http://www.ruby-lang.org/en/community/mailing-lists) or on websites like
-(http://stackoverflow.com).
-
-Bug reports should be filed at http://bugs.ruby-lang.org
-
-== The Author
-
-Ruby was originally designed and developed by Yukihiro Matsumoto (Matz) in 1995.
-
-<mailto:matz@ruby-lang.org>
-
---
-Local variables:
-mode: rdoc
-end:
diff --git a/README.EXT b/README.EXT
index b1a816c271..48b8d964c4 100644
--- a/README.EXT
+++ b/README.EXT
@@ -1,1598 +1 @@
-# README.EXT -  -*- RDoc -*- created at: Mon Aug  7 16:45:54 JST 1995
-
-This document explains how to make extension libraries for Ruby.
-
-= Basic Knowledge
-
-In C, variables have types and data do not have types.  In contrast,
-Ruby variables do not have a static type, and data themselves have
-types, so data will need to be converted between the languages.
-
-Data in Ruby are represented by the C type `VALUE'.  Each VALUE data
-has its data-type.
-
-To retrieve C data from a VALUE, you need to:
-
-1. Identify the VALUE's data type
-2. Convert the VALUE into C data
-
-Converting to the wrong data type may cause serious problems.
-
-== Data-Types
-
-The Ruby interpreter has the following data types:
-
-T_NIL       :: nil
-T_OBJECT    :: ordinary object
-T_CLASS     :: class
-T_MODULE    :: module
-T_FLOAT     :: floating point number
-T_STRING    :: string
-T_REGEXP    :: regular expression
-T_ARRAY     :: array
-T_HASH      :: associative array
-T_STRUCT    :: (Ruby) structure
-T_BIGNUM    :: multi precision integer
-T_FIXNUM    :: Fixnum(31bit or 63bit integer)
-T_COMPLEX   :: complex number
-T_RATIONAL  :: rational number
-T_FILE      :: IO
-T_TRUE      :: true
-T_FALSE     :: false
-T_DATA      :: data
-T_SYMBOL    :: symbol
-
-In addition, there are several other types used internally:
-
-T_ICLASS    :: included module
-T_MATCH     :: MatchData object
-T_UNDEF     :: undefined
-T_NODE      :: syntax tree node
-T_ZOMBIE    :: object awaiting finalization
-
-Most of the types are represented by C structures.
-
-== Check Data Type of the VALUE
-
-The macro TYPE() defined in ruby.h shows the data type of the VALUE.
-TYPE() returns the constant number T_XXXX described above.  To handle
-data types, your code will look something like this:
-
-  switch (TYPE(obj)) {
-    case T_FIXNUM:
-      /* process Fixnum */
-      break;
-    case T_STRING:
-      /* process String */
-      break;
-    case T_ARRAY:
-      /* process Array */
-      break;
-    default:
-      /* raise exception */
-      rb_raise(rb_eTypeError, "not valid value");
-      break;
-  }
-
-There is the data-type check function
-
-  void Check_Type(VALUE value, int type)
-
-which raises an exception if the VALUE does not have the type
-specified.
-
-There are also faster check macros for fixnums and nil.
-
-  FIXNUM_P(obj)
-  NIL_P(obj)
-
-== Convert VALUE into C Data
-
-The data for type T_NIL, T_FALSE, T_TRUE are nil, false, true
-respectively.  They are singletons for the data type.
-The equivalent C constants are: Qnil, Qfalse, Qtrue.
-Note that Qfalse is false in C also (i.e. 0), but not Qnil.
-
-The T_FIXNUM data is a 31bit or 63bit length fixed integer.
-This size is depend on the size of long: if long is 32bit then
-T_FIXNUM is 31bit, if long is 64bit then T_FIXNUM is 63bit.
-T_FIXNUM can be converted to a C integer by using the
-FIX2INT() macro or FIX2LONG().  Though you have to check that the
-data is really FIXNUM before using them, they are faster.  FIX2LONG()
-never raises exceptions, but FIX2INT() raises RangeError if the
-result is bigger or smaller than the size of int.
-There are also NUM2INT() and NUM2LONG() which converts any Ruby
-numbers into C integers.  These macros includes a type check,
-so an exception will be raised if the conversion failed.  NUM2DBL()
-can be used to retrieve the double float value in the same way.
-
-You can use the macros
-StringValue() and StringValuePtr() to get a char* from a VALUE.
-StringValue(var) replaces var's value with the result of "var.to_str()".
-StringValuePtr(var) does same replacement and returns char*
-representation of var.  These macros will skip the replacement if var
-is a String.  Notice that the macros take only the lvalue as their
-argument, to change the value of var in place.
-
-You can also use the macro named StringValueCStr(). This is just
-like StringValuePtr(), but always add nul character at the end of
-the result. If the result contains nul character, this macro causes
-the ArgumentError exception.
-StringValuePtr() doesn't guarantee the existence of a nul at the end
-of the result, and the result may contain nul.
-
-Other data types have corresponding C structures, e.g. struct RArray
-for T_ARRAY etc. The VALUE of the type which has the corresponding
-structure can be cast to retrieve the pointer to the struct.  The
-casting macro will be of the form RXXXX for each data type; for
-instance, RARRAY(obj).  See "ruby.h".  However, we do not recommend
-to access RXXXX data directly because these data structure is complex.
-Use corresponding rb_xxx() functions to access internal struct.
-For example, to access an entry of array, use rb_ary_entry(ary, offset)
-and rb_ary_store(ary, offset, obj).
-
-There are some accessing macros for structure members, for example
-`RSTRING_LEN(str)' to get the size of the Ruby String object.  The
-allocated region can be accessed by `RSTRING_PTR(str)'.
-
-Notice: Do not change the value of the structure directly, unless you
-are responsible for the result.  This ends up being the cause of
-interesting bugs.
-
-== Convert C Data into VALUE
-
-To convert C data to Ruby values:
-
-FIXNUM ::
-
-  left shift 1 bit, and turn on LSB.
-
-Other pointer values::
-
-  cast to VALUE.
-
-You can determine whether a VALUE is pointer or not by checking its LSB.
-
-Notice Ruby does not allow arbitrary pointer values to be a VALUE.  They
-should be pointers to the structures which Ruby knows about.  The known
-structures are defined in <ruby.h>.
-
-To convert C numbers to Ruby values, use these macros.
-
-INT2FIX() :: for integers within 31bits.
-INT2NUM() :: for arbitrary sized integer.
-
-INT2NUM() converts an integer into a Bignum if it is out of the FIXNUM
-range, but is a bit slower.
-
-== Manipulating Ruby Data
-
-As I already mentioned, it is not recommended to modify an object's
-internal structure.  To manipulate objects, use the functions supplied
-by the Ruby interpreter. Some (not all) of the useful functions are
-listed below:
-
-=== String Functions
-
-rb_str_new(const char *ptr, long len) ::
-
-  Creates a new Ruby string.
-
-rb_str_new2(const char *ptr) ::
-rb_str_new_cstr(const char *ptr) ::
-
-  Creates a new Ruby string from a C string.  This is equivalent to
-  rb_str_new(ptr, strlen(ptr)).
-
-rb_tainted_str_new(const char *ptr, long len) ::
-
-  Creates a new tainted Ruby string.  Strings from external data
-  sources should be tainted.
-
-rb_tainted_str_new2(const char *ptr) ::
-rb_tainted_str_new_cstr(const char *ptr) ::
-
-  Creates a new tainted Ruby string from a C string.
-
-rb_sprintf(const char *format, ...) ::
-rb_vsprintf(const char *format, va_list ap) ::
-
-  Creates a new Ruby string with printf(3) format.
-
-  Note: In the format string, %i is used for Object#to_s (or Object#inspect if
-  '+' flag is set) output (and related argument must be a VALUE).  For integers
-  in format strings, use %d.
-
-rb_str_cat(VALUE str, const char *ptr, long len) ::
-
-  Appends len bytes of data from ptr to the Ruby string.
-
-rb_str_cat2(VALUE str, const char* ptr) ::
-
-  Appends C string ptr to Ruby string str.  This function is
-  equivalent to rb_str_cat(str, ptr, strlen(ptr)).
-
-rb_str_catf(VALUE str, const char* format, ...) ::
-rb_str_vcatf(VALUE str, const char* format, va_list ap) ::
-
-  Appends C string format and successive arguments to Ruby string
-  str according to a printf-like format.  These functions are
-  equivalent to rb_str_cat2(str, rb_sprintf(format, ...)) and
-  rb_str_cat2(str, rb_vsprintf(format, ap)), respectively.
-
-rb_enc_str_new(const char *ptr, long len, rb_encoding *enc) ::
-rb_enc_str_new_cstr(const char *ptr, rb_encoding *enc) ::
-
-  Creates a new Ruby string with the specified encoding.
-
-rb_usascii_str_new(const char *ptr, long len) ::
-rb_usascii_str_new_cstr(const char *ptr) ::
-
-  Creates a new Ruby string with encoding US-ASCII.
-
-rb_str_resize(VALUE str, long len) ::
-
-  Resizes Ruby string to len bytes.  If str is not modifiable, this
-  function raises an exception.  The length of str must be set in
-  advance.  If len is less than the old length the content beyond
-  len bytes is discarded, else if len is greater than the old length
-  the content beyond the old length bytes will not be preserved but
-  will be garbage.  Note that RSTRING_PTR(str) may change by calling
-  this function.
-
-rb_str_set_len(VALUE str, long len) ::
-
-  Sets the length of Ruby string.  If str is not modifiable, this
-  function raises an exception.  This function preserves the content
-  upto len bytes, regardless RSTRING_LEN(str).  len must not exceed
-  the capacity of str.
-
-=== Array Functions
-
-rb_ary_new() ::
-
-  Creates an array with no elements.
-
-rb_ary_new2(long len) ::
-rb_ary_new_capa(long len) ::
-
-  Creates an array with no elements, allocating internal buffer
-  for len elements.
-
-rb_ary_new3(long n, ...) ::
-rb_ary_new_from_args(long n, ...) ::
-
-  Creates an n-element array from the arguments.
-
-rb_ary_new4(long n, VALUE *elts) ::
-rb_ary_new_from_values(long n, VALUE *elts) ::
-
-  Creates an n-element array from a C array.
-
-rb_ary_to_ary(VALUE obj) ::
-
-  Converts the object into an array.
-  Equivalent to Object#to_ary.
-
-There are many functions to operate an array.  They may dump core if other
-types are given.
-
-rb_ary_aref(argc, VALUE *argv, VALUE ary) ::
-
-  Equivalent to Array#[].
-
-rb_ary_entry(VALUE ary, long offset) ::
-
-  ary[offset]
-
-rb_ary_store(VALUE ary, long offset, VALUE obj) ::
-
-  ary[offset] = obj
-
-rb_ary_subseq(VALUE ary, long beg, long len) ::
-
-  ary[beg, len]
-
-rb_ary_push(VALUE ary, VALUE val) ::
-rb_ary_pop(VALUE ary) ::
-rb_ary_shift(VALUE ary) ::
-rb_ary_unshift(VALUE ary, VALUE val) ::
-
-rb_ary_cat(VALUE ary, const VALUE *ptr, long len) ::
-
-  Appends len elements of objects from ptr to the array.
-
-= Extending Ruby with C
-
-== Adding New Features to Ruby
-
-You can add new features (classes, methods, etc.) to the Ruby
-interpreter.  Ruby provides APIs for defining the following things:
-
-* Classes, Modules
-* Methods, Singleton Methods
-* Constants
-
-=== Class and Module Definition
-
-To define a class or module, use the functions below:
-
-  VALUE rb_define_class(const char *name, VALUE super)
-  VALUE rb_define_module(const char *name)
-
-These functions return the newly created class or module.  You may
-want to save this reference into a variable to use later.
-
-To define nested classes or modules, use the functions below:
-
-  VALUE rb_define_class_under(VALUE outer, const char *name, VALUE super)
-  VALUE rb_define_module_under(VALUE outer, const char *name)
-
-=== Method and Singleton Method Definition
-
-To define methods or singleton methods, use these functions:
-
-  void rb_define_method(VALUE klass, const char *name,
-		        VALUE (*func)(), int argc)
-
-  void rb_define_singleton_method(VALUE object, const char *name,
-			          VALUE (*func)(), int argc)
-
-The `argc' represents the number of the arguments to the C function,
-which must be less than 17.  But I doubt you'll need that many.
-
-If `argc' is negative, it specifies the calling sequence, not number of
-the arguments.
-
-If argc is -1, the function will be called as:
-
-  VALUE func(int argc, VALUE *argv, VALUE obj)
-
-where argc is the actual number of arguments, argv is the C array of
-the arguments, and obj is the receiver.
-
-If argc is -2, the arguments are passed in a Ruby array. The function
-will be called like:
-
-  VALUE func(VALUE obj, VALUE args)
-
-where obj is the receiver, and args is the Ruby array containing
-actual arguments.
-
-There are some more functions to define methods. One takes an ID
-as the name of method to be defined. See also ID or Symbol below.
-
-  void rb_define_method_id(VALUE klass, ID name,
-                           VALUE (*func)(ANYARGS), int argc)
-
-There are two functions to define private/protected methods:
-
-  void rb_define_private_method(VALUE klass, const char *name,
-			        VALUE (*func)(), int argc)
-  void rb_define_protected_method(VALUE klass, const char *name,
-			          VALUE (*func)(), int argc)
-
-At last, rb_define_module_function defines a module functions,
-which are private AND singleton methods of the module.
-For example, sqrt is the module function defined in Math module.
-It can be called in the following way:
-
-  Math.sqrt(4)
-
-or
-
-  include Math
-  sqrt(4)
-
-To define module functions, use:
-
-  void rb_define_module_function(VALUE module, const char *name,
-				 VALUE (*func)(), int argc)
-
-In addition, function-like methods, which are private methods defined
-in the Kernel module, can be defined using:
-
-  void rb_define_global_function(const char *name, VALUE (*func)(), int argc)
-
-To define an alias for the method,
-
-  void rb_define_alias(VALUE module, const char* new, const char* old);
-
-To define a reader/writer for an attribute,
-
-  void rb_define_attr(VALUE klass, const char *name, int read, int write)
-
-To define and undefine the `allocate' class method,
-
-  void rb_define_alloc_func(VALUE klass, VALUE (*func)(VALUE klass));
-  void rb_undef_alloc_func(VALUE klass);
-
-func has to take the klass as the argument and return a newly
-allocated instance.  This instance should be as empty as possible,
-without any expensive (including external) resources.
-
-=== Constant Definition
-
-We have 2 functions to define constants:
-
-  void rb_define_const(VALUE klass, const char *name, VALUE val)
-  void rb_define_global_const(const char *name, VALUE val)
-
-The former is to define a constant under specified class/module.  The
-latter is to define a global constant.
-
-== Use Ruby Features from C
-
-There are several ways to invoke Ruby's features from C code.
-
-=== Evaluate Ruby Programs in a String
-
-The easiest way to use Ruby's functionality from a C program is to
-evaluate the string as Ruby program.  This function will do the job:
-
-  VALUE rb_eval_string(const char *str)
-
-Evaluation is done under the current context, thus current local variables
-of the innermost method (which is defined by Ruby) can be accessed.
-
-Note that the evaluation can raise an exception. There is a safer
-function:
-
-  VALUE rb_eval_string_protect(const char *str, int *state)
-
-It returns nil when an error occur. Moreover, *state is zero if str was
-successfully evaluated, or nonzero otherwise.
-
-=== ID or Symbol
-
-You can invoke methods directly, without parsing the string.  First I
-need to explain about ID.  ID is the integer number to represent
-Ruby's identifiers such as variable names.  The Ruby data type
-corresponding to ID is Symbol.  It can be accessed from Ruby in the
-form:
-
-  :Identifier
-
-or
-
-  :"any kind of string"
-
-You can get the ID value from a string within C code by using
-
-  rb_intern(const char *name)
-  rb_intern_str(VALUE name)
-
-You can retrieve ID from Ruby object (Symbol or String) given as an
-argument by using
-
-  rb_to_id(VALUE symbol)
-  rb_check_id(volatile VALUE *name)
-  rb_check_id_cstr(const char *name, long len, rb_encoding *enc)
-
-These functions try to convert the argument to a String if it was not
-a Symbol nor a String.  The second function stores the converted
-result into *name, and returns 0 if the string is not a known symbol.
-After this function returned a non-zero value, *name is always a
-Symbol or a String, otherwise it is a String if the result is 0.
-The third function takes NUL-terminated C string, not Ruby VALUE.
-
-You can convert C ID to Ruby Symbol by using
-
-  VALUE ID2SYM(ID id)
-
-and to convert Ruby Symbol object to ID, use
-
-  ID SYM2ID(VALUE symbol)
-
-=== Invoke Ruby Method from C
-
-To invoke methods directly, you can use the function below
-
-  VALUE rb_funcall(VALUE recv, ID mid, int argc, ...)
-
-This function invokes a method on the recv, with the method name
-specified by the symbol mid.
-
-=== Accessing the Variables and Constants
-
-You can access class variables and instance variables using access
-functions.  Also, global variables can be shared between both
-environments.  There's no way to access Ruby's local variables.
-
-The functions to access/modify instance variables are below:
-
-  VALUE rb_ivar_get(VALUE obj, ID id)
-  VALUE rb_ivar_set(VALUE obj, ID id, VALUE val)
-
-id must be the symbol, which can be retrieved by rb_intern().
-
-To access the constants of the class/module:
-
-  VALUE rb_const_get(VALUE obj, ID id)
-
-See also Constant Definition above.
-
-= Information Sharing Between Ruby and C
-
-=== Ruby Constants That C Can Be Accessed From C
-
-As stated in section 1.3,
-the following Ruby constants can be referred from C.
-
-  Qtrue
-  Qfalse
-
-Boolean values.  Qfalse is false in C also (i.e. 0).
-
-  Qnil
-
-Ruby nil in C scope.
-
-== Global Variables Shared Between C and Ruby
-
-Information can be shared between the two environments using shared global
-variables.  To define them, you can use functions listed below:
-
-  void rb_define_variable(const char *name, VALUE *var)
-
-This function defines the variable which is shared by both environments.
-The value of the global variable pointed to by `var' can be accessed
-through Ruby's global variable named `name'.
-
-You can define read-only (from Ruby, of course) variables using the
-function below.
-
-  void rb_define_readonly_variable(const char *name, VALUE *var)
-
-You can defined hooked variables.  The accessor functions (getter and
-setter) are called on access to the hooked variables.
-
-  void rb_define_hooked_variable(const char *name, VALUE *var,
-				 VALUE (*getter)(), void (*setter)())
-
-If you need to supply either setter or getter, just supply 0 for the
-hook you don't need.  If both hooks are 0, rb_define_hooked_variable()
-works just like rb_define_variable().
-
-The prototypes of the getter and setter functions are as follows:
-
-  VALUE (*getter)(ID id, VALUE *var);
-  void (*setter)(VALUE val, ID id, VALUE *var);
-
-
-Also you can define a Ruby global variable without a corresponding C
-variable.  The value of the variable will be set/get only by hooks.
-
-  void rb_define_virtual_variable(const char *name,
-				  VALUE (*getter)(), void (*setter)())
-
-The prototypes of the getter and setter functions are as follows:
-
-  VALUE (*getter)(ID id);
-  void (*setter)(VALUE val, ID id);
-
-
-== Encapsulate C Data into a Ruby Object
-
-To wrap and objectify a C pointer as a Ruby object (so called
-DATA), use Data_Wrap_Struct().
-
-  Data_Wrap_Struct(klass, mark, free, sval)
-
-Data_Wrap_Struct() returns a created DATA object.  The klass argument
-is the class for the DATA object.  The mark argument is the function
-to mark Ruby objects pointed by this data.  The free argument is the
-function to free the pointer allocation.  If this is -1, the pointer
-will be just freed.  The functions mark and free will be called from
-garbage collector.
-
-These mark / free functions are invoked during GC execution.  No
-object allocations are allowed during it, so do not allocate ruby
-objects inside them.
-
-You can allocate and wrap the structure in one step.
-
-  Data_Make_Struct(klass, type, mark, free, sval)
-
-This macro returns an allocated Data object, wrapping the pointer to
-the structure, which is also allocated.  This macro works like:
-
-  (sval = ALLOC(type), Data_Wrap_Struct(klass, mark, free, sval))
-
-Arguments klass, mark, and free work like their counterparts in
-Data_Wrap_Struct().  A pointer to the allocated structure will be
-assigned to sval, which should be a pointer of the type specified.
-
-To retrieve the C pointer from the Data object, use the macro
-Data_Get_Struct().
-
-  Data_Get_Struct(obj, type, sval)
-
-A pointer to the structure will be assigned to the variable sval.
-
-See the example below for details.
-
-= Example - Creating dbm Extension
-
-OK, here's the example of making an extension library.  This is the
-extension to access DBMs.  The full source is included in the ext/
-directory in the Ruby's source tree.
-
-== Make the Directory
-
-  % mkdir ext/dbm
-
-Make a directory for the extension library under ext directory.
-
-== Design the Library
-
-You need to design the library features, before making it.
-
-== Write the C Code
-
-You need to write C code for your extension library.  If your library
-has only one source file, choosing ``LIBRARY.c'' as a file name is
-preferred.  On the other hand, in case your library has multiple source
-files, avoid choosing ``LIBRARY.c'' for a file name.  It may conflict
-with an intermediate file ``LIBRARY.o'' on some platforms.
-Note that some functions in mkmf library described below generate
-a file ``conftest.c'' for checking with compilation.  You shouldn't
-choose ``conftest.c'' as a name of a source file.
-
-Ruby will execute the initializing function named ``Init_LIBRARY'' in
-the library.  For example, ``Init_dbm()'' will be executed when loading
-the library.
-
-Here's the example of an initializing function.
-
-  void
-  Init_dbm(void)
-  {
-      /* define DBM class */
-      cDBM = rb_define_class("DBM", rb_cObject);
-      /* DBM includes Enumerate module */
-      rb_include_module(cDBM, rb_mEnumerable);
-
-      /* DBM has class method open(): arguments are received as C array */
-      rb_define_singleton_method(cDBM, "open", fdbm_s_open, -1);
-
-      /* DBM instance method close(): no args */
-      rb_define_method(cDBM, "close", fdbm_close, 0);
-      /* DBM instance method []: 1 argument */
-      rb_define_method(cDBM, "[]", fdbm_fetch, 1);
-
-      /* ... */
-
-      /* ID for a instance variable to store DBM data */
-      id_dbm = rb_intern("dbm");
-  }
-
-The dbm extension wraps the dbm struct in the C environment using
-Data_Make_Struct.
-
-  struct dbmdata {
-      int  di_size;
-      DBM *di_dbm;
-  };
-
-  obj = Data_Make_Struct(klass, struct dbmdata, 0, free_dbm, dbmp);
-
-This code wraps the dbmdata structure into a Ruby object.  We avoid
-wrapping DBM* directly, because we want to cache size information.
-
-To retrieve the dbmdata structure from a Ruby object, we define the
-following macro:
-
-  #define GetDBM(obj, dbmp) {\
-      Data_Get_Struct(obj, struct dbmdata, dbmp);\
-      if (dbmp->di_dbm == 0) closed_dbm();\
-  }
-
-This sort of complicated macro does the retrieving and close checking for
-the DBM.
-
-There are three kinds of way to receive method arguments.  First,
-methods with a fixed number of arguments receive arguments like this:
-
-  static VALUE
-  fdbm_delete(VALUE obj, VALUE keystr)
-  {
-        /* ... */
-  }
-
-The first argument of the C function is the self, the rest are the
-arguments to the method.
-
-Second, methods with an arbitrary number of arguments receive
-arguments like this:
-
-  static VALUE
-  fdbm_s_open(int argc, VALUE *argv, VALUE klass)
-  {
-      /* ... */
-      if (rb_scan_args(argc, argv, "11", &file, &vmode) == 1) {
-          mode = 0666;		/* default value */
-      }
-      /* ... */
-  }
-
-The first argument is the number of method arguments, the second
-argument is the C array of the method arguments, and the third
-argument is the receiver of the method.
-
-You can use the function rb_scan_args() to check and retrieve the
-arguments.  The third argument is a string that specifies how to
-capture method arguments and assign them to the following VALUE
-references.
-
-
-The following is an example of a method that takes arguments by Ruby's
-array:
-
-  static VALUE
-  thread_initialize(VALUE thread, VALUE args)
-  {
-      /* ... */
-  }
-
-The first argument is the receiver, the second one is the Ruby array
-which contains the arguments to the method.
-
-*Notice*: GC should know about global variables which refer to Ruby's objects,
-but are not exported to the Ruby world.  You need to protect them by
-
-  void rb_global_variable(VALUE *var)
-
-== Prepare extconf.rb
-
-If the file named extconf.rb exists, it will be executed to generate
-Makefile.
-
-extconf.rb is the file for checking compilation conditions etc.  You
-need to put
-
-  require 'mkmf'
-
-at the top of the file.  You can use the functions below to check
-various conditions.
-
-  have_macro(macro[, headers[, opt]]): check whether macro is defined
-  have_library(lib[, func[, headers[, opt]]]): check whether library containing function exists
-  find_library(lib[, func, *paths]): find library from paths
-  have_func(func[, headers[, opt]): check whether function exists
-  have_var(var[, headers[, opt]]): check whether variable exists
-  have_header(header[, preheaders[, opt]]): check whether header file exists
-  find_header(header, *paths): find header from paths
-  have_framework(fw): check whether framework exists (for MacOS X)
-  have_struct_member(type, member[, headers[, opt]]): check whether struct has member
-  have_type(type[, headers[, opt]]): check whether type exists
-  find_type(type, opt, *headers): check whether type exists in headers
-  have_const(const[, headers[, opt]]): check whether constant is defined
-  check_sizeof(type[, headers[, opts]]): check size of type
-  check_signedness(type[, headers[, opts]]): check signedness of type
-  convertible_int(type[, headers[, opts]]): find convertible integer type
-  find_executable(bin[, path]): find executable file path
-  create_header(header): generate configured header
-  create_makefile(target[, target_prefix]): generate Makefile
-
-See MakeMakefile for full documentation of these functions.
-
-The value of the variables below will affect the Makefile.
-
-  $CFLAGS: included in CFLAGS make variable (such as -O)
-  $CPPFLAGS: included in CPPFLAGS make variable (such as -I, -D)
-  $LDFLAGS: included in LDFLAGS make variable (such as -L)
-  $objs: list of object file names
-
-Normally, the object files list is automatically generated by searching
-source files, but you must define them explicitly if any sources will
-be generated while building.
-
-If a compilation condition is not fulfilled, you should not call
-``create_makefile''.  The Makefile will not be generated, compilation will
-not be done.
-
-== Prepare Depend (Optional)
-
-If the file named depend exists, Makefile will include that file to
-check dependencies.  You can make this file by invoking
-
-  % gcc -MM *.c > depend
-
-It's harmless.  Prepare it.
-
-== Generate Makefile
-
-Try generating the Makefile by:
-
-  ruby extconf.rb
-
-If the library should be installed under vendor_ruby directory
-instead of site_ruby directory, use --vendor option as follows.
-
-  ruby extconf.rb --vendor
-
-You don't need this step if you put the extension library under the ext
-directory of the ruby source tree.  In that case, compilation of the
-interpreter will do this step for you.
-
-== Run make
-
-Type
-
-  make
-
-to compile your extension.  You don't need this step either if you have
-put the extension library under the ext directory of the ruby source tree.
-
-== Debug
-
-You may need to rb_debug the extension.  Extensions can be linked
-statically by adding the directory name in the ext/Setup file so that
-you can inspect the extension with the debugger.
-
-== Done! Now You Have the Extension Library
-
-You can do anything you want with your library.  The author of Ruby
-will not claim any restrictions on your code depending on the Ruby API.
-Feel free to use, modify, distribute or sell your program.
-
-= Appendix A. Ruby Source Files Overview
-
-== Ruby Language Core
-
-class.c    :: classes and modules
-error.c    :: exception classes and exception mechanism
-gc.c       :: memory management
-load.c     :: library loading
-object.c   :: objects
-variable.c :: variables and constants
-
-== Ruby Syntax Parser
-
-parse.y  :: grammar definition
-parse.c  :: automatically generated from parse.y
-keywords :: reserved keywords
-lex.c    :: automatically generated from keywords
-
-== Ruby Evaluator (a.k.a. YARV)
-
-  compile.c
-  eval.c
-  eval_error.c
-  eval_jump.c
-  eval_safe.c
-  insns.def           : definition of VM instructions
-  iseq.c              : implementation of VM::ISeq
-  thread.c            : thread management and context switching
-  thread_win32.c      : thread implementation
-  thread_pthread.c    : ditto
-  vm.c
-  vm_dump.c
-  vm_eval.c
-  vm_exec.c
-  vm_insnhelper.c
-  vm_method.c
-
-  opt_insns_unif.def  : instruction unification
-  opt_operand.def     : definitions for optimization
-
-    -> insn*.inc      : automatically generated
-    -> opt*.inc       : automatically generated
-    -> vm.inc         : automatically generated
-
-== Regular Expression Engine (Oniguruma)
-
-  regex.c
-  regcomp.c
-  regenc.c
-  regerror.c
-  regexec.c
-  regparse.c
-  regsyntax.c
-
-== Utility Functions
-
-debug.c    :: debug symbols for C debugger
-dln.c      :: dynamic loading
-st.c       :: general purpose hash table
-strftime.c :: formatting times
-util.c     :: misc utilities
-
-== Ruby Interpreter Implementation
-
-  dmyext.c
-  dmydln.c
-  dmyencoding.c
-  id.c
-  inits.c
-  main.c
-  ruby.c
-  version.c
-
-  gem_prelude.rb
-  prelude.rb
-
-== Class Library
-
-array.c      :: Array
-bignum.c     :: Bignum
-compar.c     :: Comparable
-complex.c    :: Complex
-cont.c       :: Fiber, Continuation
-dir.c        :: Dir
-enum.c       :: Enumerable
-enumerator.c :: Enumerator
-file.c       :: File
-hash.c       :: Hash
-io.c         :: IO
-marshal.c    :: Marshal
-math.c       :: Math
-numeric.c    :: Numeric, Integer, Fixnum, Float
-pack.c       :: Array#pack, String#unpack
-proc.c       :: Binding, Proc
-process.c    :: Process
-random.c     :: random number
-range.c      :: Range
-rational.c   :: Rational
-re.c         :: Regexp, MatchData
-signal.c     :: Signal
-sprintf.c    :: String#sprintf
-string.c     :: String
-struct.c     :: Struct
-time.c       :: Time
-
-defs/known_errors.def :: Errno::* exception classes
--> known_errors.inc   :: automatically generated
-
-== Multilingualization
-
-encoding.c  :: Encoding
-transcode.c :: Encoding::Converter
-enc/*.c     :: encoding classes
-enc/trans/* :: codepoint mapping tables
-
-== goruby Interpreter Implementation
-
-  goruby.c
-  golf_prelude.rb     : goruby specific libraries.
-    -> golf_prelude.c : automatically generated
-
-
-= Appendix B. Ruby Extension API Reference
-
-== Types
-
-VALUE ::
-
-  The type for the Ruby object.  Actual structures are defined in ruby.h,
-  such as struct RString, etc.  To refer the values in structures, use
-  casting macros like RSTRING(obj).
-
-== Variables and Constants
-
-Qnil::
-  nil object
-
-Qtrue::
-  true object (default true value)
-
-Qfalse::
-  false object
-
-== C Pointer Wrapping
-
-Data_Wrap_Struct(VALUE klass, void (*mark)(), void (*free)(), void *sval) ::
-
-  Wrap a C pointer into a Ruby object.  If object has references to other
-  Ruby objects, they should be marked by using the mark function during
-  the GC process.  Otherwise, mark should be 0.  When this object is no
-  longer referred by anywhere, the pointer will be discarded by free
-  function.
-
-Data_Make_Struct(klass, type, mark, free, sval) ::
-
-  This macro allocates memory using malloc(), assigns it to the variable
-  sval, and returns the DATA encapsulating the pointer to memory region.
-
-Data_Get_Struct(data, type, sval) ::
-
-  This macro retrieves the pointer value from DATA, and assigns it to
-  the variable sval.
-
-== Checking Data Types
-
-TYPE(value) ::
-
-  Internal type (T_NIL, T_FIXNUM, etc.)
-
-FIXNUM_P(value) ::
-
-  Is +value+ a Fixnum?
-
-NIL_P(value) ::
-
-  Is +value+ nil?
-
-void Check_Type(VALUE value, int type) ::
-
-  Ensures +value+ is of the given internal +type+ or raises a TypeError
-
-SaveStringValue(value) ::
-
-  Checks that +value+ is a String and is not tainted
-
-== Data Type Conversion
-
-FIX2INT(value), INT2FIX(i) ::
-
-  Fixnum <-> integer
-
-FIX2LONG(value), LONG2FIX(l) ::
-
-  Fixnum <-> long
-
-NUM2INT(value), INT2NUM(i) ::
-
-  Numeric <-> integer
-
-NUM2UINT(value), UINT2NUM(ui) ::
-
-  Numeric <-> unsigned integer
-
-NUM2LONG(value), LONG2NUM(l) ::
-
-  Numeric <-> long
-
-NUM2ULONG(value), ULONG2NUM(ul) ::
-
-  Numeric <-> unsigned long
-
-NUM2LL(value), LL2NUM(ll) ::
-
-  Numeric <-> long long
-
-NUM2ULL(value), ULL2NUM(ull) ::
-
-  Numeric <-> unsigned long long
-
-NUM2OFFT(value), OFFT2NUM(off) ::
-
-  Numeric <-> off_t
-
-NUM2SIZET(value), SIZET2NUM(size) ::
-
-  Numeric <-> size_t
-
-NUM2SSIZET(value), SSIZET2NUM(ssize) ::
-
-  Numeric <-> ssize_t
-
-rb_integer_pack(value, words, numwords, wordsize, nails, flags), rb_integer_unpack(words, numwords, wordsize, nails, flags) ::
-
-  Numeric <-> Arbitrary size integer buffer
-
-NUM2DBL(value) ::
-
-  Numeric -> double
-
-rb_float_new(f) ::
-
-  double -> Float
-
-StringValue(value) ::
-
-  Object with #to_str -> String
-
-StringValuePtr(value) ::
-
-  Object with #to_str -> pointer to String data
-
-StringValueCStr(value) ::
-
-  Object with #to_str -> pointer to String data without NULL bytes
-
-rb_str_new2(s) ::
-
-  char * -> String
-
-== Defining Class and Module
-
-VALUE rb_define_class(const char *name, VALUE super) ::
-
-  Defines a new Ruby class as a subclass of super.
-
-VALUE rb_define_class_under(VALUE module, const char *name, VALUE super) ::
-
-  Creates a new Ruby class as a subclass of super, under the module's
-  namespace.
-
-VALUE rb_define_module(const char *name) ::
-
-  Defines a new Ruby module.
-
-VALUE rb_define_module_under(VALUE module, const char *name) ::
-
-  Defines a new Ruby module under the module's namespace.
-
-void rb_include_module(VALUE klass, VALUE module) ::
-
-  Includes module into class.  If class already includes it, just ignored.
-
-void rb_extend_object(VALUE object, VALUE module) ::
-
-  Extend the object with the module's attributes.
-
-== Defining Global Variables
-
-void rb_define_variable(const char *name, VALUE *var) ::
-
-  Defines a global variable which is shared between C and Ruby.  If name
-  contains a character which is not allowed to be part of the symbol,
-  it can't be seen from Ruby programs.
-
-void rb_define_readonly_variable(const char *name, VALUE *var) ::
-
-  Defines a read-only global variable.  Works just like
-  rb_define_variable(), except the defined variable is read-only.
-
-void rb_define_virtual_variable(const char *name, VALUE (*getter)(), VALUE (*setter)()) ::
-
-  Defines a virtual variable, whose behavior is defined by a pair of C
-  functions.  The getter function is called when the variable is
-  referenced.  The setter function is called when the variable is set to a
-  value.  The prototype for getter/setter functions are:
-
-    VALUE getter(ID id)
-    void setter(VALUE val, ID id)
-
-  The getter function must return the value for the access.
-
-void rb_define_hooked_variable(const char *name, VALUE *var, VALUE (*getter)(), VALUE (*setter)()) ::
-
-  Defines hooked variable.  It's a virtual variable with a C variable.
-  The getter is called as
-
-    VALUE getter(ID id, VALUE *var)
-
-  returning a new value.  The setter is called as
-
-    void setter(VALUE val, ID id, VALUE *var)
-
-  GC requires C global variables which hold Ruby values to be marked.
-
-void rb_global_variable(VALUE *var)
-
-  Tells GC to protect these variables.
-
-== Constant Definition
-
-void rb_define_const(VALUE klass, const char *name, VALUE val) ::
-
-  Defines a new constant under the class/module.
-
-void rb_define_global_const(const char *name, VALUE val) ::
-
-  Defines a global constant.  This is just the same as
-
-    rb_define_const(cKernal, name, val)
-
-== Method Definition
-
-rb_define_method(VALUE klass, const char *name, VALUE (*func)(), int argc) ::
-
-  Defines a method for the class.  func is the function pointer.  argc
-  is the number of arguments.  if argc is -1, the function will receive
-  3 arguments: argc, argv, and self.  if argc is -2, the function will
-  receive 2 arguments, self and args, where args is a Ruby array of
-  the method arguments.
-
-rb_define_private_method(VALUE klass, const char *name, VALUE (*func)(), int argc) ::
-
-  Defines a private method for the class.  Arguments are same as
-  rb_define_method().
-
-rb_define_singleton_method(VALUE klass, const char *name, VALUE (*func)(), int argc) ::
-
-  Defines a singleton method.  Arguments are same as rb_define_method().
-
-rb_scan_args(int argc, VALUE *argv, const char *fmt, ...) ::
-
-  Retrieve argument from argc and argv to given VALUE references
-  according to the format string.  The format can be described in ABNF
-  as follows:
-
-    scan-arg-spec  := param-arg-spec [option-hash-arg-spec] [block-arg-spec]
-
-    param-arg-spec := pre-arg-spec [post-arg-spec] / post-arg-spec /
-                      pre-opt-post-arg-spec
-    pre-arg-spec   := num-of-leading-mandatory-args [num-of-optional-args]
-    post-arg-spec  := sym-for-variable-length-args
-                      [num-of-trailing-mandatory-args]
-    pre-opt-post-arg-spec := num-of-leading-mandatory-args num-of-optional-args
-                             num-of-trailing-mandatory-args
-    option-hash-arg-spec := sym-for-option-hash-arg
-    block-arg-spec := sym-for-block-arg
-
-    num-of-leading-mandatory-args  := DIGIT ; The number of leading
-                                            ; mandatory arguments
-    num-of-optional-args           := DIGIT ; The number of optional
-                                            ; arguments
-    sym-for-variable-length-args   := "*"   ; Indicates that variable
-                                            ; length arguments are
-                                            ; captured as a ruby array
-    num-of-trailing-mandatory-args := DIGIT ; The number of trailing
-                                            ; mandatory arguments
-    sym-for-option-hash-arg        := ":"   ; Indicates that an option
-                                            ; hash is captured if the last
-                                            ; argument is a hash or can be
-                                            ; converted to a hash with
-                                            ; #to_hash.  When the last
-                                            ; argument is nil, it is
-                                            ; captured if it is not
-                                            ; ambiguous to take it as
-                                            ; empty option hash; i.e. '*'
-                                            ; is not specified and
-                                            ; arguments are given more
-                                            ; than sufficient.
-    sym-for-block-arg              := "&"   ; Indicates that an iterator
-                                            ; block should be captured if
-                                            ; given
-
-  For example, "12" means that the method requires at least one
-  argument, and at most receives three (1+2) arguments.  So, the format
-  string must be followed by three variable references, which are to be
-  assigned to captured arguments.  For omitted arguments, variables are
-  set to Qnil.  NULL can be put in place of a variable reference, which
-  means the corresponding captured argument(s) should be just dropped.
-
-  The number of given arguments, excluding an option hash or iterator
-  block, is returned.
-
-== Invoking Ruby method
-
-VALUE rb_funcall(VALUE recv, ID mid, int narg, ...) ::
-
-  Invokes a method.  To retrieve mid from a method name, use rb_intern().
-  Able to call even private/protected methods.
-
-VALUE rb_funcall2(VALUE recv, ID mid, int argc, VALUE *argv) ::
-VALUE rb_funcallv(VALUE recv, ID mid, int argc, VALUE *argv) ::
-
-  Invokes a method, passing arguments as an array of values.
-  Able to call even private/protected methods.
-
-VALUE rb_funcallv_public(VALUE recv, ID mid, int argc, VALUE *argv) ::
-
-  Invokes a method, passing arguments as an array of values.
-  Able to call only public methods.
-
-VALUE rb_eval_string(const char *str) ::
-
-  Compiles and executes the string as a Ruby program.
-
-ID rb_intern(const char *name) ::
-
-  Returns ID corresponding to the name.
-
-char *rb_id2name(ID id) ::
-
-  Returns the name corresponding ID.
-
-char *rb_class2name(VALUE klass) ::
-
-  Returns the name of the class.
-
-int rb_respond_to(VALUE object, ID id) ::
-
-  Returns true if the object responds to the message specified by id.
-
-== Instance Variables
-
-VALUE rb_iv_get(VALUE obj, const char *name) ::
-
-  Retrieve the value of the instance variable.  If the name is not
-  prefixed by `@', that variable shall be inaccessible from Ruby.
-
-VALUE rb_iv_set(VALUE obj, const char *name, VALUE val) ::
-
-  Sets the value of the instance variable.
-
-== Control Structure
-
-VALUE rb_block_call(VALUE recv, ID mid, int argc, VALUE * argv, VALUE (*func) (ANYARGS), VALUE data2) ::
-
-  Calls a method on the recv, with the method name specified by the
-  symbol mid, with argc arguments in argv, supplying func as the
-  block. When func is called as the block, it will receive the value
-  from yield as the first argument, and data2 as the second argument.
-  When yielded with multiple values (in C, rb_yield_values(),
-  rb_yield_values2() and rb_yield_splat()), data2 is packed as an Array,
-  whereas yielded values can be gotten via argc/argv of the third/fourth
-  arguments.
-
-[OBSOLETE] VALUE rb_iterate(VALUE (*func1)(), void *arg1, VALUE (*func2)(), void *arg2) ::
-
-  Calls the function func1, supplying func2 as the block.  func1 will be
-  called with the argument arg1.  func2 receives the value from yield as
-  the first argument, arg2 as the second argument.
-
-  When rb_iterate is used in 1.9, func1 has to call some Ruby-level method.
-  This function is obsolete since 1.9; use rb_block_call instead.
-
-VALUE rb_yield(VALUE val) ::
-
-  Evaluates the block with value val.
-
-VALUE rb_rescue(VALUE (*func1)(), VALUE arg1, VALUE (*func2)(), VALUE arg2) ::
-
-  Calls the function func1, with arg1 as the argument.  If an exception
-  occurs during func1, it calls func2 with arg2 as the argument.  The
-  return value of rb_rescue() is the return value from func1 if no
-  exception occurs, from func2 otherwise.
-
-VALUE rb_ensure(VALUE (*func1)(), VALUE arg1, VALUE (*func2)(), VALUE arg2) ::
-
-  Calls the function func1 with arg1 as the argument, then calls func2
-  with arg2 if execution terminated.  The return value from
-  rb_ensure() is that of func1 when no exception occurred.
-
-VALUE rb_protect(VALUE (*func) (VALUE), VALUE arg, int *state) ::
-
-  Calls the function func with arg as the argument.  If no exception
-  occurred during func, it returns the result of func and *state is zero.
-  Otherwise, it returns Qnil and sets *state to nonzero.  If state is
-  NULL, it is not set in both cases.
-  You have to clear the error info with rb_set_errinfo(Qnil) when
-  ignoring the caught exception.
-
-void rb_jump_tag(int state) ::
-
-  Continues the exception caught by rb_protect() and rb_eval_string_protect().
-  state must be the returned value from those functions.  This function
-  never return to the caller.
-
-void rb_iter_break() ::
-
-  Exits from the current innermost block.  This function never return to
-  the caller.
-
-void rb_iter_break_value(VALUE value) ::
-
-  Exits from the current innermost block with the value.  The block will
-  return the given argument value.  This function never return to the
-  caller.
-
-== Exceptions and Errors
-
-void rb_warn(const char *fmt, ...) ::
-
-  Prints a warning message according to a printf-like format.
-
-void rb_warning(const char *fmt, ...) ::
-
-  Prints a warning message according to a printf-like format, if
-  $VERBOSE is true.
-
-void rb_raise(rb_eRuntimeError, const char *fmt, ...) ::
-
-  Raises RuntimeError.  The fmt is a format string just like printf().
-
-void rb_raise(VALUE exception, const char *fmt, ...) ::
-
-  Raises a class exception.  The fmt is a format string just like printf().
-
-void rb_fatal(const char *fmt, ...) ::
-
-  Raises a fatal error, terminates the interpreter.  No exception handling
-  will be done for fatal errors, but ensure blocks will be executed.
-
-void rb_bug(const char *fmt, ...) ::
-
-  Terminates the interpreter immediately.  This function should be
-  called under the situation caused by the bug in the interpreter.  No
-  exception handling nor ensure execution will be done.
-
-Note: In the format string, %i is used for Object#to_s (or Object#inspect if
-'+' flag is set) output (and related argument must be a VALUE).  For integers
-in format strings, use %d.
-
-== Initialize and Start the Interpreter
-
-The embedding API functions are below (not needed for extension libraries):
-
-void ruby_init() ::
-
-  Initializes the interpreter.
-
-void ruby_options(int argc, char **argv) ::
-
-  Process command line arguments for the interpreter.
-
-void ruby_run() ::
-
-  Starts execution of the interpreter.
-
-void ruby_script(char *name) ::
-
-  Specifies the name of the script ($0).
-
-== Hooks for the Interpreter Events
-
-  void rb_add_event_hook(rb_event_hook_func_t func, rb_event_flag_t events,
-                         VALUE data)
-
-Adds a hook function for the specified interpreter events.
-events should be OR'ed value of:
-
-  RUBY_EVENT_LINE
-  RUBY_EVENT_CLASS
-  RUBY_EVENT_END
-  RUBY_EVENT_CALL
-  RUBY_EVENT_RETURN
-  RUBY_EVENT_C_CALL
-  RUBY_EVENT_C_RETURN
-  RUBY_EVENT_RAISE
-  RUBY_EVENT_ALL
-
-The definition of rb_event_hook_func_t is below:
-
-  typedef void (*rb_event_hook_func_t)(rb_event_t event, VALUE data,
-                                       VALUE self, ID id, VALUE klass)
-
-The third argument `data' to rb_add_event_hook() is passed to the hook
-function as the second argument, which was the pointer to the current
-NODE in 1.8.  See RB_EVENT_HOOKS_HAVE_CALLBACK_DATA below.
-
-  int rb_remove_event_hook(rb_event_hook_func_t func)
-
-Removes the specified hook function.
-
-== Macros for Compatibility
-
-Some macros to check API compatibilities are available by default.
-
-NORETURN_STYLE_NEW ::
-
-  Means that NORETURN macro is functional style instead of prefix.
-
-HAVE_RB_DEFINE_ALLOC_FUNC ::
-
-  Means that function rb_define_alloc_func() is provided, that means the
-  allocation framework is used.  This is same as the result of
-  have_func("rb_define_alloc_func", "ruby.h").
-
-HAVE_RB_REG_NEW_STR ::
-
-  Means that function rb_reg_new_str() is provided, that creates Regexp
-  object from String object.  This is same as the result of
-  have_func("rb_reg_new_str", "ruby.h").
-
-HAVE_RB_IO_T ::
-
-  Means that type rb_io_t is provided.
-
-USE_SYMBOL_AS_METHOD_NAME ::
-
-  Means that Symbols will be returned as method names, e.g.,
-  Module#methods, #singleton_methods and so on.
-
-HAVE_RUBY_*_H ::
-
-  Defined in ruby.h and means corresponding header is available.  For
-  instance, when HAVE_RUBY_ST_H is defined you should use ruby/st.h not
-  mere st.h.
-
-RB_EVENT_HOOKS_HAVE_CALLBACK_DATA ::
-
-  Means that rb_add_event_hook() takes the third argument `data', to be
-  passed to the given event hook function.
-
-= Appendix C. Functions available for use in extconf.rb
-
-See documentation for {mkmf}[rdoc-ref:MakeMakefile].
-
-= Appendix D. Generational GC
-
-Ruby 2.1 introduced a generational garbage collector (called RGenGC).
-RGenGC (mostly) keeps compatibility.
-
-Generally, the use of the technique called write barriers is required in
-extension libraries for generational GC
-(http://en.wikipedia.org/wiki/Garbage_collection_%28computer_science%29).
-RGenGC works fine without write barriers in extension libraries.
-
-If your library adheres to the following tips, performance can
-be further improved. Especially, the "Don't touch pointers directly" section is
-important.
-
-== Incompatibility
-
-You can't write RBASIC(obj)->klass field directly because it is const
-value now.
-
-Basically you should not write this field because MRI expects it to be
-an immutable field, but if you want to do it in your extension you can
-use the following functions:
-
-VALUE rb_obj_hide(VALUE obj) ::
-
-  Clear RBasic::klass field. The object will be an internal object.
-  ObjectSpace::each_object can't find this object.
-
-VALUE rb_obj_reveal(VALUE obj, VALUE klass) ::
-
-  Reset RBasic::klass to be klass.
-  We expect the `klass' is hidden class by rb_obj_hide().
-
-== Write barriers
-
-RGenGC doesn't require write barriers to support generational GC.
-However, caring about write barrier can improve the performance of
-RGenGC. Please check the following tips.
-
-=== Don't touch pointers directly
-
-In MRI (include/ruby/ruby.h), some macros to acquire pointers to the
-internal data structures are supported such as RARRAY_PTR(),
-RSTRUCT_PTR() and so on.
-
-DO NOT USE THESE MACROS and instead use the corresponding C-APIs such as
-rb_ary_aref(), rb_ary_store() and so on.
-
-=== Consider whether to insert write barriers
-
-You don't need to care about write barriers if you only use built-in
-types.
-
-If you support T_DATA objects, you may consider using write barriers.
-
-Inserting write barriers into T_DATA objects only works with the
-following type objects: (a) long-lived objects, (b) when a huge number
-of objects are generated and (c) container-type objects that have
-references to other objects. If your extension provides such a type of
-T_DATA objects, consider inserting write barriers.
-
-(a): short-lived objects don't become old generation objects.
-(b): only a few oldgen objects don't have performance impact.
-(c): only a few references don't have performance impact.
-
-Inserting write barriers is a very difficult hack, it is easy to
-introduce critical bugs. And inserting write barriers has several areas
-of overhead. Basically we don't recommend you insert write barriers.
-Please carefully consider the risks.
-
-=== Combine with built-in types
-
-Please consider utilizing built-in types. Most built-in types support
-write barrier, so you can use them to avoid manually inserting write
-barriers.
-
-For example, if your T_DATA has references to other objects, then you
-can move these references to Array. A T_DATA object only has a reference
-to an array object. Or you can also use a Struct object to gather a
-T_DATA object (without any references) and an that Array contains
-references.
-
-With use of such techniques, you don't need to insert write barriers
-anymore.
-
-=== Insert write barriers
-
-[AGAIN] Inserting write barriers is a very difficult hack, and it is
-easy to introduce critical bugs. And inserting write barriers has
-several areas of overhead. Basically we don't recommend you insert write
-barriers. Please carefully consider the risks.
-
-Before inserting write barriers, you need to know about RGenGC algorithm
-(gc.c will help you). Macros and functions to insert write barriers are
-available in in include/ruby/ruby.h. An example is available in iseq.c.
-
-For a complete guide for RGenGC and write barriers, please refer to
-<https://bugs.ruby-lang.org/projects/ruby-trunk/wiki/RGenGC>.
-
-/*
- * Local variables:
- * fill-column: 70
- * end:
- */
+Moved to doc/extension.rdoc
diff --git a/README.EXT.ja b/README.EXT.ja
index 17be4e4c1c..f884ecbb0e 100644
--- a/README.EXT.ja
+++ b/README.EXT.ja
@@ -1,1650 +1 @@
-# README.EXT.ja -  -*- RDoc -*- created at: Mon Aug  7 16:45:54 JST 1995
-
-Rubyの拡張ライブラリの作り方を説明します．
-
-= 基礎知識
-
-Cの変数には型があり，データには型がありません．ですから，た
-とえばポインタをintの変数に代入すると，その値は整数として取
-り扱われます．逆にRubyの変数には型がなく，データに型がありま
-す．この違いのため，CとRubyは相互に変換しなければ，お互いの
-データをアクセスできません．
-
-RubyのデータはVALUEというCの型で表現されます．VALUE型のデー
-タはそのデータタイプを自分で知っています．このデータタイプと
-いうのはデータ(オブジェクト)の実際の構造を意味していて，Ruby
-のクラスとはまた違ったものです．
-
-VALUEからCにとって意味のあるデータを取り出すためには
-
-1. VALUEのデータタイプを知る
-2. VALUEをCのデータに変換する
-
-の両方が必要です．(1)を忘れると間違ったデータの変換が行われ
-て，最悪プログラムがcore dumpします．
-
-== データタイプ
-
-Rubyにはユーザが使う可能性のある以下のタイプがあります．
-
-T_NIL      :: nil
-T_OBJECT   :: 通常のオブジェクト
-T_CLASS    :: クラス
-T_MODULE   :: モジュール
-T_FLOAT    :: 浮動小数点数
-T_STRING   :: 文字列
-T_REGEXP   :: 正規表現
-T_ARRAY    :: 配列
-T_HASH     :: 連想配列
-T_STRUCT   :: (Rubyの)構造体
-T_BIGNUM   :: 多倍長整数
-T_FIXNUM   :: Fixnum(31bitまたは63bit長整数)
-T_COMPLEX  :: 複素数
-T_RATIONAL :: 有理数
-T_FILE     :: 入出力
-T_TRUE     :: 真
-T_FALSE    :: 偽
-T_DATA     :: データ
-T_SYMBOL   :: シンボル
-
-その他に内部で利用されている以下のタイプがあります．
-
-  T_ICLASS
-  T_MATCH
-  T_UNDEF
-  T_NODE
-  T_ZOMBIE
-
-ほとんどのタイプはCの構造体で実装されています．
-
-== VALUEのデータタイプをチェックする
-
-ruby.hではTYPE()というマクロが定義されていて，VALUEのデータ
-タイプを知ることが出来ます．TYPE()マクロは上で紹介したT_XXXX
-の形式の定数を返します．VALUEのデータタイプに応じて処理する
-場合には，TYPE()の値で分岐することになります．
-
-  switch (TYPE(obj)) {
-    case T_FIXNUM:
-      /* FIXNUMの処理 */
-      break;
-    case T_STRING:
-      /* 文字列の処理 */
-      break;
-    case T_ARRAY:
-      /* 配列の処理 */
-      break;
-    default:
-      /* 例外を発生させる */
-      rb_raise(rb_eTypeError, "not valid value");
-      break;
-  }
-
-それとデータタイプをチェックして，正しくなければ例外を発生す
-る関数が用意されています．
-
-  void Check_Type(VALUE value, int type)
-
-この関数はvalueがtypeで無ければ，例外を発生させます．引数と
-して与えられたVALUEのデータタイプが正しいかどうかチェックす
-るためには，この関数を使います．
-
-FIXNUMとNILに関してはより高速な判別マクロが用意されています．
-
-  FIXNUM_P(obj)
-  NIL_P(obj)
-
-== VALUEをCのデータに変換する
-
-データタイプがT_NIL，T_FALSE，T_TRUEである時，データはそれぞ
-れnil，false，trueです．このデータタイプのオブジェクトはひと
-つずつしか存在しません．
-
-データタイプがT_FIXNUMの時，これは31bitまたは63bitのサイズを
-持つ整数です．longのサイズが32bitのプラットフォームであれば
-31bitに，longのサイズが64bitのプラットフォームであれば63bit
-になります. FIXNUM を C の整数に変換するためにはマクロ
-「FIX2INT()」または「FIX2LONG()」を使います．これらのマクロ
-を使用する際には事前にデータタイプがFIXNUMであることを確認す
-る必要がありますが，比較的高速に変換を行うことができます．ま
-た，「FIX2LONG()」は例外を発生しませんが，「FIX2INT()」は変
-換結果がintのサイズに収まらない場合には例外を発生します．
-それから，FIXNUMに限らずRubyのデータを整数に変換する
-「NUM2INT()」および「NUM2LONG()」というマクロがあります．こ
-れらのマクロはマクロはデータタイプのチェック無しで使えます
-(整数に変換できない場合には例外が発生する)．同様にチェック無
-で使える変換マクロはdoubleを取り出す「NUM2DBL()」があります．
-
-char* を取り出す場合， StringValue() と StringValuePtr()
-を使います．
-StringValue(var) は var が String
-であれば何もせず，そうでなければ var を var.to_str() の結果
-に置き換えるマクロ，StringValuePtr(var) は同様に var を
-String に置き換えてから var のバイト列表現に対する char* を
-返すマクロです．var の内容を直接置き換える処理が入るので，
-var は lvalue である必要があります．
-また，StringValuePtr() に類似した StringValueCStr() というマ
-クロもあります．StringValueCStr(var) は var を String に置き
-換えてから var の文字列表現に対する char* を返します．返され
-る文字列の末尾には nul 文字が付加されます．なお，途中に nul
-文字が含まれる場合は ArgumentError が発生します．
-一方，StringValuePtr() では，末尾に nul 文字がある保証はなく，
-途中に nul 文字が含まれている可能性もあります．
-
-それ以外のデータタイプは対応するCの構造体があります．対応す
-る構造体のあるVALUEはそのままキャスト(型変換)すれば構造体の
-ポインタに変換できます．
-
-構造体は「struct RXxxxx」という名前でruby.hで定義されていま
-す．例えば文字列は「struct RString」です．実際に使う可能性が
-あるのは文字列と配列くらいだと思います．
-
-ruby.hでは構造体へキャストするマクロも「RXXXXX()」(全部大文
-字にしたもの)という名前で提供されています(例: RSTRING())．た
-だし、構造体への直接のアクセスはできるだけ避け，対応する
-rb_xxxx() といった関数を使うようにして下さい．例えば，配列の
-要素へアクセスする場合は，rb_ary_entry(ary, offset)，
-rb_ary_store(ary, offset, obj) を利用するようにして下さい．
-
-構造体からデータを取り出すマクロが提供されています．文字列
-strの長さを得るためには「RSTRING_LEN(str)」とし，文字列strを
-char*として得るためには「RSTRING_PTR(str)」とします．
-
-Rubyの構造体を直接アクセスする時に気をつけなければならないこ
-とは，配列や文字列の構造体の中身は参照するだけで，直接変更し
-ないことです．直接変更した場合，オブジェクトの内容の整合性が
-とれなくなって，思わぬバグの原因になります．
-
-== CのデータをVALUEに変換する
-
-VALUEの実際の構造は
-
-FIXNUMの場合 ::
-
-  1bit左シフトして，LSBを立てる．
-
-その他のポインタの場合 ::
-
-  そのままVALUEにキャストする．
-
-となっています．よって，LSBをチェックすればVALUEがFIXNUMかど
-うかわかるわけです(ポインタのLSBが立っていないことを仮定して
-いる)．
-
-ですから，FIXNUM以外のRubyのオブジェクトの構造体は単にVALUE
-にキャストするだけでVALUEに変換出来ます．ただし，任意の構造
-体がVALUEにキャスト出来るわけではありません．キャストするの
-はRubyの知っている構造体(ruby.hで定義されているstruct RXxxx
-のもの)だけです．
-
-FIXNUMに関しては変換マクロを経由する必要があります．Cの整数
-からVALUEに変換するマクロは以下のものがあります．必要に応じ
-て使い分けてください．
-
-INT2FIX() :: もとの整数が31bitまたは63bit以内に収まる自信
-      	     がある時
-INT2NUM() :: 任意の整数からVALUEへ
-
-INT2NUM()は整数がFIXNUMの範囲に収まらない場合，Bignumに変換
-してくれます(が，少し遅い)．
-
-== Rubyのデータを操作する
-
-先程も述べた通り，Rubyの構造体をアクセスする時に内容の更新を
-行うことは勧められません．で，Rubyのデータを操作する時には
-Rubyが用意している関数を用いてください．
-
-ここではもっとも使われるであろう文字列と配列の生成/操作を行
-う関数をあげます(全部ではないです)．
-
-=== 文字列に対する関数
-
-rb_str_new(const char *ptr, long len) ::
-
-  新しいRubyの文字列を生成する．
-
-rb_str_new2(const char *ptr)
-rb_str_new_cstr(const char *ptr)
-
-  Cの文字列からRubyの文字列を生成する．この関数の機能は
-  rb_str_new(ptr, strlen(ptr))と同等である．
-
-rb_tainted_str_new(const char *ptr, long len)
-
-  汚染マークが付加された新しいRubyの文字列を生成する．外部
-  からのデータに基づく文字列には汚染マークが付加されるべき
-  である．
-
-rb_tainted_str_new2(const char *ptr)
-rb_tainted_str_new_cstr(const char *ptr)
-
-  Cの文字列から汚染マークが付加されたRubyの文字列を生成する．
-
-rb_sprintf(const char *format, ...)
-rb_vsprintf(const char *format, va_list ap)
-
-  Cの文字列formatと続く引数をprintf(3)のフォーマットにしたがって
-  整形し，Rubyの文字列を生成する．
-
-  注意: %iはObject#to_s('+'フラグが指定されているときはObject#inspect)を
-  使ったVALUEの出力に使用されているため，整数には%dを使用すること．
-
-rb_str_cat(VALUE str, const char *ptr, long len)
-
-  Rubyの文字列strにlenバイトの文字列ptrを追加する．
-
-rb_str_cat2(VALUE str, const char* ptr)
-
-  Rubyの文字列strにCの文字列ptrを追加する．この関数の機能は
-  rb_str_cat(str, ptr, strlen(ptr))と同等である．
-
-rb_str_catf(VALUE str, const char* format, ...)
-rb_str_vcatf(VALUE str, const char* format, va_list ap)
-
-  Cの文字列formatと続く引数をprintf(3)のフォーマットにしたがって
-  整形し，Rubyの文字列strに追加する．この関数の機能は，それぞれ
-  rb_str_cat2(str, rb_sprintf(format, ...)) や
-  rb_str_cat2(str, rb_vsprintf(format, ap)) と同等である．
-
-rb_enc_str_new(const char *ptr, long len, rb_encoding *enc)
-rb_enc_str_new_cstr(const char *ptr, rb_encoding *enc)
-
-  指定されたエンコーディングでRubyの文字列を生成する.
-
-rb_usascii_str_new(const char *ptr, long len)
-rb_usascii_str_new_cstr(const char *ptr)
-
-  エンコーディングがUS-ASCIIのRubyの文字列を生成する.
-
-rb_str_resize(VALUE str, long len)
-
-  Rubyの文字列のサイズをlenバイトに変更する．strの長さは前
-  以てセットされていなければならない．lenが元の長さよりも短
-  い時は，lenバイトを越えた部分の内容は捨てられる．lenが元
-  の長さよりも長い時は，元の長さを越えた部分の内容は保存さ
-  れないでゴミになるだろう．この関数の呼び出しによって
-  RSTRING_PTR(str)が変更されるかもしれないことに注意．
-
-rb_str_set_len(VALUE str, long len)
-
-  Rubyの文字列のサイズをlenバイトにセットする．strが変更可
-  能でなければ例外が発生する．RSTRING_LEN(str)とは無関係に，
-  lenバイトまでの内容は保存される．lenはstrの容量を越えてい
-  てはならない．
-
-
-== 配列に対する関数
-
-rb_ary_new()
-
-  要素が0の配列を生成する．
-
-rb_ary_new2(long len)
-rb_ary_new_capa(long len)
-
-  要素が0の配列を生成する．len要素分の領域をあらかじめ割り
-  当てておく．
-
-rb_ary_new3(long n, ...)
-rb_ary_new_from_args(long n, ...)
-
-  引数で指定したn要素を含む配列を生成する．
-
-rb_ary_new4(long n, VALUE *elts)
-rb_ary_new_from_values(long n, VALUE *elts)
-
-  配列で与えたn要素の配列を生成する．
-
-rb_ary_to_ary(VALUE obj)
-
-  オブジェクトを配列に変換する.
-  Object#to_aryと同等である.
-
-他にも配列を操作する関数が多数ある. これらは
-引数aryに配列を渡さなければならない. さもないと
-コアを吐く.
-
-rb_ary_aref(argc, VALUE *argv, VALUE ary)
-
-  Array#[]と同等.
-
-rb_ary_entry(VALUE ary, long offset)
-
-  ary[offset]
-
-rb_ary_store(VALUE ary, long offset, VALUE obj) ::
-
-  ary[offset] = obj
-
-rb_ary_subseq(VALUE ary, long beg, long len)
-
-  ary[beg, len]
-
-rb_ary_push(VALUE ary, VALUE val)
-rb_ary_pop(VALUE ary)
-rb_ary_shift(VALUE ary)
-rb_ary_unshift(VALUE ary, VALUE val)
-
-rb_ary_cat(VALUE ary, const VALUE *ptr, long len)
-
-  配列aryにptrからlen個のオブジェクトを追加する．
-
-= Rubyの機能を使う
-
-原理的にRubyで書けることはCでも書けます．RubyそのものがCで記
-述されているんですから，当然といえば当然なんですけど．ここで
-はRubyの拡張に使うことが多いだろうと予測される機能を中心に紹
-介します．
-
-== Rubyに機能を追加する
-
-Rubyで提供されている関数を使えばRubyインタプリタに新しい機能
-を追加することができます．Rubyでは以下の機能を追加する関数が
-提供されています．
-
-* クラス，モジュール
-* メソッド，特異メソッドなど
-* 定数
-
-では順に紹介します．
-
-=== クラス/モジュール定義
-
-クラスやモジュールを定義するためには，以下の関数を使います．
-
-  VALUE rb_define_class(const char *name, VALUE super)
-  VALUE rb_define_module(const char *name)
-
-これらの関数は新しく定義されたクラスやモジュールを返します．
-メソッドや定数の定義にこれらの値が必要なので，ほとんどの場合
-は戻り値を変数に格納しておく必要があるでしょう．
-
-クラスやモジュールを他のクラスの内部にネストして定義する時に
-は以下の関数を使います．
-
-  VALUE rb_define_class_under(VALUE outer, const char *name, VALUE super)
-  VALUE rb_define_module_under(VALUE outer, const char *name)
-
-=== メソッド/特異メソッド定義
-
-メソッドや特異メソッドを定義するには以下の関数を使います．
-
-  void rb_define_method(VALUE klass, const char *name,
-                        VALUE (*func)(), int argc)
-
-  void rb_define_singleton_method(VALUE object, const char *name,
-                                  VALUE (*func)(), int argc)
-
-
-念のため説明すると「特異メソッド」とは，その特定のオブジェク
-トに対してだけ有効なメソッドです．RubyではよくSmalltalkにお
-けるクラスメソッドとして，クラスに対する特異メソッドが使われ
-ます．
-
-これらの関数の argcという引数はCの関数へ渡される引数の数(と
-形式)を決めます．argcが0以上の時は関数に引き渡す引数の数を意
-味します．16個以上の引数は使えません(が，要りませんよね，そ
-んなに)．実際の関数には先頭の引数としてselfが与えられますの
-で，指定した数より1多い引数を持つことになります．
-
-argcが負の時は引数の数ではなく，形式を指定したことになります．
-argcが-1の時は引数を配列に入れて渡されます．argcが-2の時は引
-数はRubyの配列として渡されます．
-
-メソッドを定義する関数はまだいくつかあります. ひとつはメソッド
-名としてIDを取ります. IDについては2.2.2を参照.
-
-  void rb_define_method_id(VALUE klass, ID name,
-                           VALUE (*func)(ANYARGS), int argc)
-
-private/protectedなメソッドを定義するふたつの関数があります.
-
-  void rb_define_private_method(VALUE klass, const char *name,
-				VALUE (*func)(), int argc)
-  void rb_define_protected_method(VALUE klass, const char *name,
-			          VALUE (*func)(), int argc)
-
-privateメソッドとは関数形式でしか呼び出すことの出来ないメソッ
-ドです．
-
-最後に， rb_define_module関数はモジュール関数を定義します．
-モジュール関数とはモジュールの特異メソッドであり，同時に
-privateメソッドでもあるものです．例をあげるとMathモジュール
-のsqrt()などがあげられます．このメソッドは
-
-  Math.sqrt(4)
-
-という形式でも
-
-  include Math
-  sqrt(4)
-
-という形式でも使えます．モジュール関数を定義する関数は以下の
-通りです．
-
-  void rb_define_module_function(VALUE module, const char *name,
-		                 VALUE (*func)(), int argc)
-
-関数的メソッド(Kernelモジュールのprivate method)を定義するた
-めの関数は以下の通りです．
-
-  void rb_define_global_function(const char *name, VALUE (*func)(), int argc)
-
-
-メソッドの別名を定義するための関数は以下の通りです．
-
-  void rb_define_alias(VALUE module, const char* new, const char* old);
-
-属性の取得・設定メソッドを定義するには
-
-  void rb_define_attr(VALUE klass, const char *name, int read, int write)
-
-クラスメソッドallocateを定義したり削除したりするための関数は
-以下の通りです．
-
-  void rb_define_alloc_func(VALUE klass, VALUE (*func)(VALUE klass));
-  void rb_undef_alloc_func(VALUE klass);
-
-funcはクラスを引数として受け取って，新しく割り当てられたイン
-スタンスを返さなくてはなりません．このインスタンスは，外部リ
-ソースなどを含まない，できるだけ「空」のままにしておいたほう
-がよいでしょう．
-
-=== 定数定義
-
-拡張ライブラリが必要な定数はあらかじめ定義しておいた方が良い
-でしょう．定数を定義する関数は二つあります．
-
-  void rb_define_const(VALUE klass, const char *name, VALUE val)
-  void rb_define_global_const(const char *name, VALUE val)
-
-前者は特定のクラス/モジュールに属する定数を定義するもの，後
-者はグローバルな定数を定義するものです．
-
-== Rubyの機能をCから呼び出す
-
-既に『1.5 Rubyのデータを操作する』で一部紹介したような関数を
-使えば，Rubyの機能を実現している関数を直接呼び出すことが出来
-ます．
-
-# このような関数の一覧表はいまのところありません．ソースを見
-# るしかないですね．
-
-それ以外にもRubyの機能を呼び出す方法はいくつかあります．
-
-=== Rubyのプログラムをevalする
-
-CからRubyの機能を呼び出すもっとも簡単な方法として，文字列で
-与えられたRubyのプログラムを評価する以下の関数があります．
-
-  VALUE rb_eval_string(const char *str)
-
-この評価は現在の環境で行われます．つまり，現在のローカル変数
-などを受け継ぎます．
-
-評価は例外を発生するかもしれないことに注意しましょう. より安全
-な関数もあります.
-
-  VALUE rb_eval_string_protect(const char *str, int *state)
-
-この関数はエラーが発生するとnilを返します．そして，成功時には
-*stateはゼロに，さもなくば非ゼロになります．
-
-=== IDまたはシンボル
-
-Cから文字列を経由せずにRubyのメソッドを呼び出すこともできま
-す．その前に，Rubyインタプリタ内でメソッドや変数名を指定する
-時に使われているIDについて説明しておきましょう．
-
-IDとは変数名，メソッド名を表す整数です．Rubyの中では
-
- :識別子
-
-または
-
- :"任意の文字列"
-
-でアクセスできます．Cからこの整数を得るためには関数
-
-  rb_intern(const char *name)
-  rb_intern_str(VALUE name)
-
-を使います．Rubyから引数として与えられたシンボル(または文字
-列)をIDに変換するには以下の関数を使います．
-
-  rb_to_id(VALUE symbol)
-  rb_check_id(volatile VALUE *name)
-  rb_check_id_cstr(const char *name, long len, rb_encoding *enc)
-
-もし引数がシンボルでも文字列でもなければ、to_strメソッドで文
-字列に変換しようとします．第二の関数はその変換結果を*nameに保
-存し,その名前が既知のシンボルでない場合は0を返します．この関
-数が0以外を返した場合は*nameは常にシンボルか文字列であり、0を
-返した場合は常に文字列です．第三の関数はRubyの文字列ではなく
-NUL終端されたCの文字列を使います．
-
-=== CからRubyのメソッドを呼び出す
-
-Cから文字列を経由せずにRubyのメソッドを呼び出すためには以下
-の関数を使います．
-
-  VALUE rb_funcall(VALUE recv, ID mid, int argc, ...)
-
-この関数はオブジェクトrecvのmidで指定されるメソッドを呼び出
-します．その他に引数の指定の仕方が違う以下の関数もあります．
-
-  VALUE rb_funcall2(VALUE recv, ID mid, int argc, VALUE *argv)
-  VALUE rb_funcallv(VALUE recv, ID mid, int argc, VALUE *argv)
-  VALUE rb_apply(VALUE recv, ID mid, VALUE args)
-
-applyには引数としてRubyの配列を与えます．
-
-=== 変数/定数を参照/更新する
-
-Cから関数を使って参照・更新できるのは，定数，インスタンス変
-数です．大域変数は一部のものはCの大域変数としてアクセスでき
-ます．ローカル変数を参照する方法は公開していません．
-
-オブジェクトのインスタンス変数を参照・更新する関数は以下の通
-りです．
-
-  VALUE rb_ivar_get(VALUE obj, ID id)
-  VALUE rb_ivar_set(VALUE obj, ID id, VALUE val)
-
-idはrb_intern()で得られるものを使ってください．
-
-定数を参照するには以下の関数を使ってください．
-
-  VALUE rb_const_get(VALUE obj, ID id)
-
-定数を新しく定義するためには『2.1.3 定数定義』で紹介さ
-れている関数を使ってください．
-
-= RubyとCとの情報共有
-
-C言語とRubyの間で情報を共有する方法について解説します．
-
-== Cから参照できるRubyの定数
-
-以下のRubyの定数はCのレベルから参照できます．
-
-  Qtrue
-  Qfalse
-
-真偽値．QfalseはC言語でも偽とみなされます(つまり0)．
-
-  Qnil
-
-C言語から見た「nil」．
-
-== CとRubyで共有される大域変数
-
-CとRubyで大域変数を使って情報を共有できます．共有できる大域
-変数にはいくつかの種類があります．そのなかでもっとも良く使わ
-れると思われるのはrb_define_variable()です．
-
-  void rb_define_variable(const char *name, VALUE *var)
-
-この関数はRubyとCとで共有する大域変数を定義します．変数名が
-`$'で始まらない時には自動的に追加されます．この変数の値を変
-更すると自動的にRubyの対応する変数の値も変わります．
-
-またRuby側からは更新できない変数もあります．このread onlyの
-変数は以下の関数で定義します．
-
-  void rb_define_readonly_variable(const char *name, VALUE *var)
-
-これら変数の他にhookをつけた大域変数を定義できます．hook付き
-の大域変数は以下の関数を用いて定義します．hook付き大域変数の
-値の参照や設定はhookで行う必要があります．
-
-  void rb_define_hooked_variable(const char *name, VALUE *var,
-				 VALUE (*getter)(), void (*setter)())
-
-この関数はCの関数によってhookのつけられた大域変数を定義しま
-す．変数が参照された時には関数getterが，変数に値がセットされ
-た時には関数setterが呼ばれる．hookを指定しない場合はgetterや
-setterに0を指定します．
-# getterもsetterも0ならばrb_define_variable()と同じになる．
-
-getterとsetterの仕様は次の通りです．
-
-  VALUE (*getter)(ID id, VALUE *var);
-  void (*setter)(VALUE val, ID id, VALUE *var);
-
-
-それから，対応するCの変数を持たないRubyの大域変数を定義する
-こともできます. その変数の値はフック関数のみによって取得・設定
-されます.
-
-  void rb_define_virtual_variable(const char *name,
-				  VALUE (*getter)(), void (*setter)())
-
-この関数によって定義されたRubyの大域変数が参照された時には
-getterが，変数に値がセットされた時にはsetterが呼ばれます．
-
-getterとsetterの仕様は以下の通りです．
-
-  (*getter)(ID id);
-  (*setter)(VALUE val, ID id);
-
-== CのデータをRubyオブジェクトにする
-
-Cの世界で定義されたデータ(構造体)をRubyのオブジェクトとして
-取り扱いたい場合がありえます．このような場合には，Dataという
-RubyオブジェクトにCの構造体(へのポインタ)をくるむことでRuby
-オブジェクトとして取り扱えるようになります．
-
-Dataオブジェクトを生成して構造体をRubyオブジェクトにカプセル
-化するためには，以下のマクロを使います．
-
-  Data_Wrap_Struct(klass, mark, free, sval)
-
-このマクロの戻り値は生成されたDataオブジェクトです．
-
-klassはこのDataオブジェクトのクラスです．markはこの構造体が
-Rubyのオブジェクトへの参照がある時に使う関数です．そのような
-参照を含まない時には0を指定します．
-
-# そのような参照は勧められません．
-
-freeはこの構造体がもう不要になった時に呼ばれる関数です．この
-関数がガーベージコレクタから呼ばれます．これが-1の場合は，単
-純に開放されます．
-
-markおよびfree関数はGC実行中に呼び出されます.
-なお, GC実行中はRubyオブジェクトのアロケーションは禁止されま
-す. よって, markおよびfree関数でRubyオブジェクトのアロケーシ
-ョンは行わないでください.
-
-Cの構造体の割当とDataオブジェクトの生成を同時に行うマクロと
-して以下のものが提供されています．
-
-  Data_Make_Struct(klass, type, mark, free, sval)
-
-このマクロの戻り値は生成されたDataオブジェクトです．このマク
-ロは以下の式のように働きます:
-
-  (sval = ALLOC(type), Data_Wrap_Struct(klass, mark, free, sval))
-
-klass, mark, freeはData_Wrap_Structと同じ働きをします．type
-は割り当てるC構造体の型です．割り当てられた構造体は変数sval
-に代入されます．この変数の型は (type*) である必要があります．
-
-Dataオブジェクトからポインタを取り出すのは以下のマクロを用い
-ます．
-
-  Data_Get_Struct(obj, type, sval)
-
-Cの構造体へのポインタは変数svalに代入されます．
-
-これらのDataの使い方はちょっと分かりにくいので，後で説明する
-例題を参照してください．
-
-= 例題 - dbmパッケージを作る
-
-ここまでの説明でとりあえず拡張ライブラリは作れるはずです．
-Rubyのextディレクトリにすでに含まれているdbmライブラリを例に
-して段階的に説明します．
-
-== ディレクトリを作る
-
-  % mkdir ext/dbm
-
-Ruby 1.1からは任意のディレクトリでダイナミックライブラリを作
-ることができるようになりました．Rubyに静的にリンクする場合に
-はRubyを展開したディレクトリの下，extディレクトリの中に拡張
-ライブラリ用のディレクトリを作る必要があります．名前は適当に
-選んで構いません．
-
-== 設計する
-
-まあ，当然なんですけど，どういう機能を実現するかどうかまず設
-計する必要があります．どんなクラスをつくるか，そのクラスには
-どんなメソッドがあるか，クラスが提供する定数などについて設計
-します．
-
-== Cコードを書く
-
-拡張ライブラリ本体となるC言語のソースを書きます．C言語のソー
-スがひとつの時には「ライブラリ名.c」を選ぶと良いでしょう．C
-言語のソースが複数の場合には逆に「ライブラリ名.c」というファ
-イル名は避ける必要があります．オブジェクトファイルとモジュー
-ル生成時に中間的に生成される「ライブラリ名.o」というファイル
-とが衝突するからです．また，後述する mkmf ライブラリのいくつ
-かの関数がコンパイルを要するテストのために「conftest.c」とい
-うファイル名を使用することに注意してください．ソースファイル
-名として「conftest.c」を使用してはなりません．
-
-Rubyは拡張ライブラリをロードする時に「Init_ライブラリ名」と
-いう関数を自動的に実行します．dbmライブラリの場合「Init_dbm」
-です．この関数の中でクラス，モジュール，メソッド，定数などの
-定義を行います．dbm.cから一部引用します．
-
-  void
-  Init_dbm(void)
-  {
-      /* DBMクラスを定義する */
-      cDBM = rb_define_class("DBM", rb_cObject);
-      /* DBMはEnumerateモジュールをインクルードする */
-      rb_include_module(cDBM, rb_mEnumerable);
-
-      /* DBMクラスのクラスメソッドopen(): 引数はCの配列で受ける */
-      rb_define_singleton_method(cDBM, "open", fdbm_s_open, -1);
-
-      /* DBMクラスのメソッドclose(): 引数はなし */
-      rb_define_method(cDBM, "close", fdbm_close, 0);
-      /* DBMクラスのメソッド[]: 引数は1個 */
-      rb_define_method(cDBM, "[]", fdbm_fetch, 1);
-
-      /* ... */
-
-      /* DBMデータを格納するインスタンス変数名のためのID */
-      id_dbm = rb_intern("dbm");
-  }
-
-DBMライブラリはdbmのデータと対応するオブジェクトになるはずで
-すから，Cの世界のdbmをRubyの世界に取り込む必要があります．
-
-dbm.cではData_Make_Structを以下のように使っています．
-
-  struct dbmdata {
-      int  di_size;
-      DBM *di_dbm;
-  };
-
-
-  obj = Data_Make_Struct(klass, struct dbmdata, 0, free_dbm, dbmp);
-
-ここではdbmstruct構造体へのポインタをDataにカプセル化してい
-ます．DBM*を直接カプセル化しないのはclose()した時の処理を考
-えてのことです．
-
-Dataオブジェクトからdbmstruct構造体のポインタを取り出すため
-に以下のマクロを使っています．
-
-  #define GetDBM(obj, dbmp) {\
-      Data_Get_Struct(obj, struct dbmdata, dbmp);\
-      if (dbmp->di_dbm == 0) closed_dbm();\
-  }
-
-ちょっと複雑なマクロですが，要するにdbmdata構造体のポインタ
-の取り出しと，closeされているかどうかのチェックをまとめてい
-るだけです．
-
-DBMクラスにはたくさんメソッドがありますが，分類すると3種類の
-引数の受け方があります．ひとつは引数の数が固定のもので，例と
-してはdeleteメソッドがあります．deleteメソッドを実装している
-fdbm_delete()はこのようになっています．
-
-  static VALUE
-  fdbm_delete(VALUE obj, VALUE keystr)
-  {
-      /* ... */
-  }
-
-引数の数が固定のタイプは第1引数がself，第2引数以降がメソッド
-の引数となります．
-
-引数の数が不定のものはCの配列で受けるものとRubyの配列で受け
-るものとがあります．dbmライブラリの中で，Cの配列で受けるもの
-はDBMのクラスメソッドであるopen()です．これを実装している関
-数fdbm_s_open()はこうなっています．
-
-  static VALUE
-  fdbm_s_open(int argc, VALUE *argv, VALUE klass)
-  {
-      /* ... */
-
-      if (rb_scan_args(argc, argv, "11", &file, &vmode) == 1) {
-  	mode = 0666;		/* default value */
-      }
-
-      /* ... */
-  }
-
-このタイプの関数は第1引数が与えられた引数の数，第2引数が与え
-られた引数の入っている配列になります．selfは第3引数として与
-えられます．
-
-この配列で与えられた引数を解析するための関数がopen()でも使わ
-れているrb_scan_args()です．第3引数に指定したフォーマットに従
-い，第4変数以降に指定したVALUEへの参照に値を代入してくれま
-す．
-
-
-引数をRubyの配列として受け取るメソッドの例には
-Thread#initializeがあります．実装はこうです．
-
-  static VALUE
-  thread_initialize(VALUE thread, VALUE args)
-  {
-      /* ... */
-  }
-
-第1引数はself，第2引数はRubyの配列です．
-
-*注意事項*
-
-Rubyと共有はしないがRubyのオブジェクトを格納する可能性のある
-Cの大域変数は以下の関数を使ってRubyインタプリタに変数の存在
-を教えてあげてください．でないとGCでトラブルを起こします．
-
-  void rb_global_variable(VALUE *var)
-
-== extconf.rbを用意する
-
-Makefileを作る場合の雛型になるextconf.rbというファイルを作り
-ます．extconf.rbはライブラリのコンパイルに必要な条件のチェッ
-クなどを行うことが目的です．まず，
-
-  require 'mkmf'
-
-をextconf.rbの先頭に置きます．extconf.rbの中では以下のRuby関
-数を使うことが出来ます．
-
-  have_library(lib, func): ライブラリの存在チェック
-  have_func(func, header): 関数の存在チェック
-  have_header(header): ヘッダファイルの存在チェック
-  create_makefile(target[, target_prefix]): Makefileの生成
-
-以下の変数を使うことができます．
-
-  $CFLAGS: コンパイル時に追加的に指定するフラグ(-Oなど)
-  $CPPFLAGS: プリプロセッサに追加的に指定するフラグ(-Iや-Dなど)
-  $LDFLAGS: リンク時に追加的に指定するフラグ(-Lなど)
-  $objs: リンクされるオブジェクトファイル名のリスト
-
-オブジェクトファイルのリストは，通常はソースファイルを検索し
-て自動的に生成されますが，makeの途中でソースを生成するような
-場合は明示的に指定する必要があります．
-
-ライブラリをコンパイルする条件が揃わず，そのライブラリをコン
-パイルしない時にはcreate_makefileを呼ばなければMakefileは生
-成されず，コンパイルも行われません．
-
-== dependを用意する
-
-もし，ディレクトリにdependというファイルが存在すれば，
-Makefileが依存関係をチェックしてくれます．
-
-  % gcc -MM *.c > depend
-
-などで作ることが出来ます．あって損は無いでしょう．
-
-== Makefileを生成する
-
-Makefileを実際に生成するためには
-
-  ruby extconf.rb
-
-とします．extconf.rbに require 'mkmf' の行がない場合にはエラー
-になりますので，引数を追加して
-
-  ruby -r mkmf extconf.rb
-
-としてください．
-
-site_ruby ディレクトリでなく，
-vendor_ruby ディレクトリにインストールする場合には
-以下のように --vendor オプションを加えてください．
-
-  ruby extconf.rb --vendor
-
-ディレクトリをext以下に用意した場合にはRuby全体のmakeの時に
-自動的にMakefileが生成されますので，このステップは不要です．
-
-== makeする
-
-動的リンクライブラリを生成する場合にはその場でmakeしてくださ
-い．必要であれば make install でインストールされます．
-
-ext以下にディレクトリを用意した場合は，Rubyのディレクトリで
-makeを実行するとMakefileを生成からmake，必要によってはそのモ
-ジュールのRubyへのリンクまで自動的に実行してくれます．
-extconf.rbを書き換えるなどしてMakefileの再生成が必要な時はま
-たRubyディレクトリでmakeしてください．
-
-拡張ライブラリはmake installでRubyライブラリのディレクトリの
-下にコピーされます．もし拡張ライブラリと協調して使うRubyで記
-述されたプログラムがあり，Rubyライブラリに置きたい場合には，
-拡張ライブラリ用のディレクトリの下に lib というディレクトリ
-を作り，そこに 拡張子 .rb のファイルを置いておけば同時にイン
-ストールされます．
-
-== デバッグ
-
-まあ，デバッグしないと動かないでしょうね．ext/Setupにディレ
-クトリ名を書くと静的にリンクするのでデバッガが使えるようにな
-ります．その分コンパイルが遅くなりますけど．
-
-== できあがり
-
-後はこっそり使うなり，広く公開するなり，売るなり，ご自由にお
-使いください．Rubyの作者は拡張ライブラリに関して一切の権利を
-主張しません．
-
-= Appendix A. Rubyのソースコードの分類
-
-Rubyのソースはいくつかに分類することが出来ます．このうちクラ
-スライブラリの部分は基本的に拡張ライブラリと同じ作り方になっ
-ています．これらのソースは今までの説明でほとんど理解できると
-思います．
-
-== Ruby言語のコア
-
-class.c    :: クラスとモジュール
-error.c    :: 例外クラスと例外機構
-gc.c       :: 記憶領域管理
-load.c     :: ライブラリのロード
-object.c   :: オブジェクト
-variable.c :: 変数と定数
-
-== Rubyの構文解析器
-
-  parse.y      : 字句解析器と構文定義
-    -> parse.c : 自動生成
-  keywords     : 予約語
-    -> lex.c   : 自動生成
-
-== Rubyの評価器 (通称YARV)
-  compile.c
-  eval.c
-  eval_error.c
-  eval_jump.c
-  eval_safe.c
-  insns.def           : 仮想機械語の定義
-  iseq.c              : VM::ISeqの実装
-  thread.c            : スレッド管理とコンテキスト切り替え
-  thread_win32.c      : スレッド実装
-  thread_pthread.c    : 同上
-  vm.c
-  vm_dump.c
-  vm_eval.c
-  vm_exec.c
-  vm_insnhelper.c
-  vm_method.c
-
-  opt_insns_unif.def  : 命令融合
-  opt_operand.def     : 最適化のための定義
-
-    -> insn*.inc      : 自動生成
-    -> opt*.inc       : 自動生成
-    -> vm.inc         : 自動生成
-
-== 正規表現エンジン (鬼車)
-
-  regex.c
-  regcomp.c
-  regenc.c
-  regerror.c
-  regexec.c
-  regparse.c
-  regsyntax.c
-
-== ユーティリティ関数
-
-debug.c    :: Cデバッガ用のデバッグシンボル
-dln.c      :: 動的ローディング
-st.c       :: 汎用ハッシュ表
-strftime.c :: 時刻整形
-util.c     :: その他のユーティリティ
-
-== Rubyコマンドの実装
-
-  dmyext.c
-  dmydln.c
-  dmyencoding.c
-  id.c
-  inits.c
-  main.c
-  ruby.c
-  version.c
-
-  gem_prelude.rb
-  prelude.rb
-
-== クラスライブラリ
-
-array.c      :: Array
-bignum.c     :: Bignum
-compar.c     :: Comparable
-complex.c    :: Complex
-cont.c       :: Fiber, Continuation
-dir.c        :: Dir
-enum.c       :: Enumerable
-enumerator.c :: Enumerator
-file.c       :: File
-hash.c       :: Hash
-io.c         :: IO
-marshal.c    :: Marshal
-math.c       :: Math
-numeric.c    :: Numeric, Integer, Fixnum, Float
-pack.c       :: Array#pack, String#unpack
-proc.c       :: Binding, Proc
-process.c    :: Process
-random.c     :: 乱数
-range.c      :: Range
-rational.c   :: Rational
-re.c         :: Regexp, MatchData
-signal.c     :: Signal
-sprintf.c    :: String#sprintf
-string.c     :: String
-struct.c     :: Struct
-time.c       :: Time
-defs/known_errors.def :: 例外クラス Errno::*
--> known_errors.inc   :: 自動生成
-
-== 多言語化
-
-encoding.c  :: Encoding
-transcode.c :: Encoding::Converter
-enc/*.c     :: エンコーディングクラス群
-enc/trans/* :: コードポイント対応表
-
-== gorubyコマンドの実装
-
-  goruby.c
-  golf_prelude.rb      : goruby固有のライブラリ
-    -> golf_prelude.c  : 自動生成
-
-= Appendix B. 拡張用関数リファレンス
-
-C言語からRubyの機能を利用するAPIは以下の通りである．
-
-== 型
-
-VALUE ::
-
-  Rubyオブジェクトを表現する型．必要に応じてキャストして用いる．
-  組み込み型を表現するCの型はruby.hに記述してあるRで始まる構造
-  体である．VALUE型をこれらにキャストするためにRで始まる構造体
-  名を全て大文字にした名前のマクロが用意されている．
-
-== 変数・定数
-
-Qnil ::
-
-  定数: nilオブジェクト
-
-Qtrue ::
-
-  定数: trueオブジェクト(真のデフォルト値)
-
-Qfalse ::
-
-  定数: falseオブジェクト
-
-== Cデータのカプセル化
-
-Data_Wrap_Struct(VALUE klass, void (*mark)(), void (*free)(), void *sval) ::
-
-  Cの任意のポインタをカプセル化したRubyオブジェクトを返す．こ
-  のポインタがRubyからアクセスされなくなった時，freeで指定した
-  関数が呼ばれる．また，このポインタの指すデータが他のRubyオブ
-  ジェクトを指している場合，markに指定する関数でマークする必要
-  がある．
-
-Data_Make_Struct(klass, type, mark, free, sval) ::
-
-  type型のメモリをmallocし，変数svalに代入した後，それをカプセ
-  ル化したデータを返すマクロ．
-
-Data_Get_Struct(data, type, sval) ::
-
-  dataからtype型のポインタを取り出し変数svalに代入するマクロ．
-
-== 型チェック
-
-  TYPE(value)
-  FIXNUM_P(value)
-  NIL_P(value)
-  void Check_Type(VALUE value, int type)
-  SafeStringValue(value)
-
-== 型変換
-
-  FIX2INT(value), INT2FIX(i)
-  FIX2LONG(value), LONG2FIX(l)
-  NUM2INT(value), INT2NUM(i)
-  NUM2UINT(value), UINT2NUM(ui)
-  NUM2LONG(value), LONG2NUM(l)
-  NUM2ULONG(value), ULONG2NUM(ul)
-  NUM2LL(value), LL2NUM(ll)
-  NUM2ULL(value), ULL2NUM(ull)
-  NUM2OFFT(value), OFFT2NUM(off)
-  NUM2SIZET(value), SIZET2NUM(size)
-  NUM2SSIZET(value), SSIZET2NUM(ssize)
-  rb_integer_pack(value, words, numwords, wordsize, nails, flags), rb_integer_unpack(words, numwords, wordsize, nails, flags)
-  NUM2DBL(value)
-  rb_float_new(f)
-  StringValue(value)
-  StringValuePtr(value)
-  StringValueCStr(value)
-  rb_str_new2(s)
-
-== クラス/モジュール定義
-
-VALUE rb_define_class(const char *name, VALUE super) ::
-
-  superのサブクラスとして新しいRubyクラスを定義する．
-
-VALUE rb_define_class_under(VALUE module, const char *name, VALUE super) ::
-
-  superのサブクラスとして新しいRubyクラスを定義し，moduleの
-  定数として定義する．
-
-VALUE rb_define_module(const char *name) ::
-
-  新しいRubyモジュールを定義する．
-
-VALUE rb_define_module_under(VALUE module, const char *name) ::
-
-  新しいRubyモジュールを定義し，moduleの定数として定義する．
-
-void rb_include_module(VALUE klass, VALUE module) ::
-
-  モジュールをインクルードする．classがすでにmoduleをインク
-  ルードしている時には何もしない(多重インクルードの禁止)．
-
-void rb_extend_object(VALUE object, VALUE module) ::
-
-  オブジェクトをモジュール(で定義されているメソッド)で拡張する．
-
-== 大域変数定義
-
-void rb_define_variable(const char *name, VALUE *var) ::
-
-  RubyとCとで共有するグローバル変数を定義する．変数名が`$'で
-  始まらない時には自動的に追加される．nameとしてRubyの識別子
-  として許されない文字(例えば` ')を含む場合にはRubyプログラ
-  ムからは見えなくなる．
-
-void rb_define_readonly_variable(const char *name, VALUE *var) ::
-
-  RubyとCとで共有するread onlyのグローバル変数を定義する．
-  read onlyであること以外はrb_define_variable()と同じ．
-
-void rb_define_virtual_variable(const char *name, VALUE (*getter)(), void (*setter)()) ::
-
-  関数によって実現されるRuby変数を定義する．変数が参照された
-  時にはgetterが，変数に値がセットされた時にはsetterが呼ばれ
-  る．
-
-void rb_define_hooked_variable(const char *name, VALUE *var, VALUE (*getter)(), void (*setter)()) ::
-
-  関数によってhookのつけられたグローバル変数を定義する．変数
-  が参照された時にはgetterが，関数に値がセットされた時には
-  setterが呼ばれる．getterやsetterに0を指定した時にはhookを
-  指定しないのと同じ事になる．
-
-void rb_global_variable(VALUE *var)
-
-  GCのため，Rubyプログラムからはアクセスされないが, Rubyオブ
-  ジェクトを含む大域変数をマークする．
-
-== 定数
-
-void rb_define_const(VALUE klass, const char *name, VALUE val) ::
-
-  定数を定義する．
-
-void rb_define_global_const(const char *name, VALUE val) ::
-
-  大域定数を定義する．
-
-    rb_define_const(rb_cObject, name, val)
-
-  と同じ意味．
-
-== メソッド定義
-
-rb_define_method(VALUE klass, const char *name, VALUE (*func)(), int argc) ::
-
-  メソッドを定義する．argcはselfを除く引数の数．argcが-1の時,
-  関数には引数の数(selfを含まない)を第1引数, 引数の配列を第2
-  引数とする形式で与えられる(第3引数はself)．argcが-2の時,
-  第1引数がself, 第2引数がargs(argsは引数を含むRubyの配列)と
-  いう形式で与えられる．
-
-rb_define_private_method(VALUE klass, const char *name, VALUE (*func)(), int argc) ::
-
-  privateメソッドを定義する．引数はrb_define_method()と同じ．
-
-rb_define_singleton_method(VALUE klass, const char *name, VALUE (*func)(), int argc) ::
-
-  特異メソッドを定義する．引数はrb_define_method()と同じ．
-
-rb_scan_args(int argc, VALUE *argv, const char *fmt, ...) ::
-
-  argc, argv形式で与えられた指定されたフォーマットに従って引
-  数を分解し，続くVALUEへの参照にセットします．このフォーマッ
-  トは，ABNFで記述すると以下の通りです．
-
-    scan-arg-spec  := param-arg-spec [option-hash-arg-spec] [block-arg-spec]
-
-    param-arg-spec := pre-arg-spec [post-arg-spec] / post-arg-spec /
-                      pre-opt-post-arg-spec
-    pre-arg-spec   := num-of-leading-mandatory-args [num-of-optional-args]
-    post-arg-spec  := sym-for-variable-length-args
-                      [num-of-trailing-mandatory-args]
-    pre-opt-post-arg-spec := num-of-leading-mandatory-args num-of-optional-args
-                             num-of-trailing-mandatory-args
-    option-hash-arg-spec := sym-for-option-hash-arg
-    block-arg-spec := sym-for-block-arg
-
-    num-of-leading-mandatory-args  := DIGIT ; 先頭に置かれる省略不能な引数の数
-    num-of-optional-args           := DIGIT ; 続いて置かれる省略可能な引数の数
-    sym-for-variable-length-args   := "*"   ; 続いて置かれる可変長引数を
-                                            ; Rubyの配列で取得するための指定
-    num-of-trailing-mandatory-args := DIGIT ; 終端に置かれる省略不能な引数の数
-    sym-for-option-hash-arg        := ":"   ; オプションハッシュを取得する
-                                            ; ための指定; 省略不能な引数の
-                                            ; 数よりも多くの引数が指定され，
-                                            ; 最後の引数がハッシュ（または
-                                            ; #to_hashで変換可能）の場合に
-                                            ; 取得される．最後の引数がnilの
-                                            ; 場合，可変長引数指定がなく，
-                                            ; 省略不能引数の数よりも多くの
-                                            ; 引数が指定された場合に取得される
-    sym-for-block-arg              := "&"   ; イテレータブロックを取得するための
-                                            ; 指定
-
-  フォーマットが"12"の場合，引数は最低1つで，3つ(1+2)まで許さ
-  れるという意味になります．従って，フォーマット文字列に続い
-  て3つのVALUEへの参照を置く必要があります．それらには取得した
-  変数がセットされます．変数への参照の代わりにNULLを指定する
-  こともでき，その場合は取得した引数の値は捨てられます．なお，
-  省略可能引数が省略された時の変数の値はnil(C言語のレベルでは
-  Qnil)になります．
-
-  返り値は与えられた引数の数です．オプションハッシュおよびイ
-  テレータブロックは数えません．
-
-== Rubyメソッド呼び出し
-
-VALUE rb_funcall(VALUE recv, ID mid, int narg, ...) ::
-
-  メソッド呼び出し．文字列からmidを得るためにはrb_intern()を
-  使う．
-  private/protectedなメソッドでも呼び出せる．
-
-VALUE rb_funcall2(VALUE recv, ID mid, int argc, VALUE *argv) ::
-VALUE rb_funcallv(VALUE recv, ID mid, int argc, VALUE *argv) ::
-
-  メソッド呼び出し．引数をargc, argv形式で渡す．
-  private/protectedなメソッドでも呼び出せる．
-
-VALUE rb_funcallv_public(VALUE recv, ID mid, int argc, VALUE *argv) ::
-
-  メソッド呼び出し．
-  publicなメソッドしか呼べない．
-
-VALUE rb_eval_string(const char *str)
-
-  文字列をRubyスクリプトとしてコンパイル・実行する．
-
-ID rb_intern(const char *name) ::
-
-  文字列に対応するIDを返す．
-
-char *rb_id2name(ID id) ::
-
-  IDに対応する文字列を返す(デバッグ用)．
-
-char *rb_class2name(VALUE klass) ::
-
-  クラスの名前を返す(デバッグ用)．クラスが名前を持たない時に
-  は, 祖先を遡って名前を持つクラスの名前を返す．
-
-int rb_respond_to(VALUE obj, ID id) ::
-
-  objがidで示されるメソッドを持つかどうかを返す．
-
-== インスタンス変数
-
-VALUE rb_iv_get(VALUE obj, const char *name) ::
-
-  objのインスタンス変数の値を得る．`@'で始まらないインスタン
-  ス変数は Rubyプログラムからアクセスできない「隠れた」イン
-  スタンス変数になる．定数は大文字の名前を持つクラス(または
-  モジュール)のインスタンス変数として実装されている．
-
-VALUE rb_iv_set(VALUE obj, const char *name, VALUE val) ::
-
-  objのインスタンス変数をvalにセットする．
-
-== 制御構造
-
-VALUE rb_block_call(VALUE obj, ID mid, int argc, VALUE * argv, VALUE (*func) (ANYARGS), VALUE data2) ::
-
-  funcをブロックとして設定し，objをレシーバ，argcとargvを引数
-  としてmidメソッドを呼び出す．funcは第一引数にyieldされた値，
-  第二引数にdata2を受け取る．複数の値がyieldされた場合(Cでは
-  rb_yield_values()とrb_yield_values2(), rb_yield_splat())，
-  data2はArrayとしてパックされている．第三, 第四引数のargcと
-  argvによってyieldされた値を取り出すことができる．
-
-[OBSOLETE] VALUE rb_iterate(VALUE (*func1)(), VALUE arg1, VALUE (*func2)(), VALUE arg2) ::
-
-  func2をブロックとして設定し, func1をイテレータとして呼ぶ．
-  func1には arg1が引数として渡され, func2には第1引数にイテレー
-  タから与えられた値, 第2引数にarg2が渡される．
-
-  1.9でrb_iterateを使う場合は, func1の中でRubyレベルのメソッド
-  を呼び出さなければならない.
-  1.9でobsoleteとなった. 代わりにrb_block_callが用意された.
-
-VALUE rb_yield(VALUE val) ::
-
-  valを値としてイテレータブロックを呼び出す．
-
-VALUE rb_rescue(VALUE (*func1)(), VALUE arg1, VALUE (*func2)(), VALUE arg2) ::
-
-  関数func1をarg1を引数に呼び出す．func1の実行中に例外が発生
-  した時には func2をarg2を引数として呼ぶ．戻り値は例外が発生
-  しなかった時はfunc1の戻り値, 例外が発生した時にはfunc2の戻
-  り値である．
-
-VALUE rb_ensure(VALUE (*func1)(), VALUE arg1, VALUE (*func2)(), VALUE arg2) ::
-
-  関数func1をarg1を引数として実行し, 実行終了後(たとえ例外が
-  発生しても) func2をarg2を引数として実行する．戻り値はfunc1
-  の戻り値である(例外が発生した時は戻らない)．
-
-VALUE rb_protect(VALUE (*func) (VALUE), VALUE arg, int *state) ::
-
-  関数funcをargを引数として実行し, 例外が発生しなければその戻
-  り値を返す．例外が発生した場合は, *stateに非0をセットして
-  Qnilを返す．
-  rb_jump_tag()を呼ばずに捕捉した例外を無視する場合には，
-  rb_set_errinfo(Qnil)でエラー情報をクリアしなければならない．
-
-void rb_jump_tag(int state) ::
-
-  rb_protect()やrb_eval_string_protect()で捕捉された例外を再
-  送する．stateはそれらの関数から返された値でなければならない．
-  この関数は直接の呼び出し元に戻らない．
-
-void rb_iter_break() ::
-
-  現在の最も内側のブロックを終了する．この関数は直接の呼び出
-  し元に戻らない．
-
-void rb_iter_break_value(VALUE value) ::
-
-  現在の最も内側のブロックをvalueで終了する．ブロックは引数で
-  与えられたvalueを返す．この関数は直接の呼び出し元に戻らない．
-
-== 例外・エラー
-
-void rb_warning(const char *fmt, ...) ::
-
-  rb_verbose時に標準エラー出力に警告情報を表示する．引数は
-  printf()と同じ．
-
-void rb_raise(rb_eRuntimeError, const char *fmt, ...) ::
-
-  RuntimeError例外を発生させる．引数はprintf()と同じ．
-
-void rb_raise(VALUE exception, const char *fmt, ...) ::
-
-  exceptionで指定した例外を発生させる．fmt以下の引数は
-  printf()と同じ．
-
-void rb_fatal(const char *fmt, ...) ::
-
-  致命的例外を発生させる．通常の例外処理は行なわれず, インター
-  プリタが終了する(ただしensureで指定されたコードは終了前に
-  実行される)．
-
-void rb_bug(const char *fmt, ...) ::
-
-  インタープリタなどプログラムのバグでしか発生するはずのない
-  状況の時呼ぶ．インタープリタはコアダンプし直ちに終了する．
-  例外処理は一切行なわれない．
-
-注意: %iはObject#to_s('+'フラグが指定されているときはObject#inspect)を
-使ったVALUEの出力に使用されているため，整数には%dを使用すること．
-
-== Rubyの初期化・実行
-
-Rubyをアプリケーションに埋め込む場合には以下のインタフェース
-を使う．通常の拡張ライブラリには必要ない．
-
-void ruby_init() ::
-
-  Rubyインタプリタの初期化を行なう．
-
-void ruby_options(int argc, char **argv) ::
-
-  Rubyインタプリタのコマンドライン引数の処理を行なう．
-
-void ruby_run() ::
-
-  Rubyインタプリタを実行する．
-
-void ruby_script(char *name) ::
-
-  Rubyのスクリプト名($0)を設定する．
-
-== インタプリタのイベントのフック
-
-  void rb_add_event_hook(rb_event_hook_func_t func, rb_event_flag_t events,
-                         VALUE data)
-
-指定されたインタプリタのイベントに対するフック関数を追加します．
-eventsは以下の値のorでなければなりません:
-
-  RUBY_EVENT_LINE
-  RUBY_EVENT_CLASS
-  RUBY_EVENT_END
-  RUBY_EVENT_CALL
-  RUBY_EVENT_RETURN
-  RUBY_EVENT_C_CALL
-  RUBY_EVENT_C_RETURN
-  RUBY_EVENT_RAISE
-  RUBY_EVENT_ALL
-
-rb_event_hook_func_tの定義は以下の通りです:
-
-  typedef void (*rb_event_hook_func_t)(rb_event_t event, VALUE data,
-                                       VALUE self, ID id, VALUE klass)
-
-rb_add_event_hook() の第3引数 data は，フック関数の第2引数と
-して渡されます．これは1.8では現在のNODEへのポインタでした．以
-下の RB_EVENT_HOOKS_HAVE_CALLBACK_DATA も参照してください．
-
-  int rb_remove_event_hook(rb_event_hook_func_t func)
-
-指定されたフック関数を削除します．
-
-== 互換性のためのマクロ
-
-APIの互換性をチェックするために以下のマクロがデフォルトで定義されています．
-
-NORETURN_STYLE_NEW ::
-
-  NORETURN マクロが関数型マクロとして定義されていることを意味する．
-
-HAVE_RB_DEFINE_ALLOC_FUNC ::
-
-  rb_define_alloc_func() 関数が提供されていること，つまり
-  allocation framework が使われることを意味する．
-  have_func("rb_define_alloc_func", "ruby.h")
-  の結果と同じ．
-
-HAVE_RB_REG_NEW_STR ::
-
-  StringオブジェクトからRegexpオブジェクトを作る
-  rb_reg_new_str() 関数が提供されていることを意味する．
-  have_func("rb_reg_new_str", "ruby.h").
-  の結果と同じ．
-
-HAVE_RB_IO_T ::
-
-  rb_io_t 型が提供されていることを意味する．
-
-USE_SYMBOL_AS_METHOD_NAME ::
-
-  メソッド名を返すメソッド，Module#methods, #singleton_methods
-  などがSymbolを返すことを意味する．
-
-HAVE_RUBY_*_H ::
-
-  ruby.h で定義されている．対応するヘッダが提供されていること
-  を意味する．たとえば，HAVE_RUBY_ST_H が定義されている場合は
-  単なる st.h ではなく ruby/st.h を使用する．
-
-RB_EVENT_HOOKS_HAVE_CALLBACK_DATA ::
-
-  rb_add_event_hook() がフック関数に渡す data を第3引数として
-  受け取ることを意味する．
-
-= Appendix C. extconf.rbで使える関数たち
-
-extconf.rbの中では利用可能なコンパイル条件チェックの関数は以
-下の通りである．
-
-have_macro(macro, headers) ::
-
-  ヘッダファイルheaderをインクルードしてマクロmacroが定義さ
-  れているかどうかチェックする．マクロが定義されている時true
-  を返す．
-
-have_library(lib, func) ::
-
-  関数funcを定義しているライブラリlibの存在をチェックする．
-  チェックに成功すると，-llibを$libsに追加し，trueを返す．
-
-find_library(lib, func, path...) ::
-
-  関数funcを定義しているライブラリlibの存在を -Lpath を追加
-  しながらチェックする．チェックに成功すると，-llibを$libsに
-  追加し，trueを返す．
-
-have_func(func, header) ::
-
-  ヘッダファイルheaderをインクルードして関数funcの存在をチェ
-  ックする．funcが標準ではリンクされないライブラリ内のもので
-  ある時には先にhave_libraryでそのライブラリをチェックしてお
-  く事．チェックに成功すると，プリプロセッサマクロ
-  `HAVE_{FUNC}` を定義し，trueを返す．
-
-have_var(var, header) ::
-
-  ヘッダファイルheaderをインクルードして変数varの存在をチェッ
-  クする．varが標準ではリンクされないライブラリ内のものであ
-  る時には先にhave_libraryでそのライブラリをチェックしておく
-  事．チェックに成功すると，プリプロセッサマクロ
-  `HAVE_{VAR}` を定義し，trueを返す．
-
-have_header(header) ::
-
-  ヘッダファイルの存在をチェックする．チェックに成功すると，
-  プリプロセッサマクロ `HAVE_{HEADER_H}` を定義し，trueを返す．
-  (スラッシュやドットはアンダースコアに置換される)
-
-find_header(header, path...) ::
-
-  ヘッダファイルheaderの存在を -Ipath を追加しながらチェック
-  する．チェックに成功すると，プリプロセッサマクロ
-  `HAVE_{HEADER_H}` を定義し，trueを返す．
-  (スラッシュやドットはアンダースコアに置換される)
-
-have_struct_member(type, member[, header[, opt]]) ::
-
-  ヘッダファイルheaderをインクルードして型typeが定義され，
-  なおかつメンバmemberが存在するかをチェックする．チェックに
-  成功すると，プリプロセッサマクロ `HAVE_{TYPE}_{MEMBER}` を
-  定義し，trueを返す．
-
-have_type(type, header, opt) ::
-
-  ヘッダファイルheaderをインクルードして型typeが存在するかを
-  チェックする．チェックに成功すると，プリプロセッサマクロ
-  `HAVE_TYPE_{TYPE}` を定義し，trueを返す．
-
-check_sizeof(type, header) ::
-
-  ヘッダファイルheaderをインクルードして型typeのchar単位サイ
-  ズを調べる．チェックに成功すると，プリプロセッサマクロ
-  `SIZEOF_{TYPE}` を定義し，そのサイズを返す．定義されていな
-  いときはnilを返す．
-
-create_makefile(target[, target_prefix]) ::
-
-  拡張ライブラリ用のMakefileを生成する．この関数を呼ばなけれ
-  ばそのライブラリはコンパイルされない．targetはモジュール名
-  を表す．
-
-find_executable(command, path) ::
-
-  コマンドcommandをFile::PATH_SEPARATORで区切られたパス名の
-  リストpathから探す．pathがnilまたは省略された場合は，環境
-  変数PATHの値を使用する．実行可能なコマンドが見つかった場合
-  はパスを含むファイル名，見つからなかった場合はnilを返す．
-
-with_config(withval[, default=nil]) ::
-
-  コマンドライン上の--with-<withval>で指定されたオプション値
-  を得る．
-
-enable_config(config, *defaults) ::
-disable_config(config, *defaults) ::
-
-  コマンドライン上の--enable-<config>または
-  --disable-<config>で指定された真偽値を得る．
-  --enable-<config>が指定されていた場合はtrue，
-  --disable-<config>が指定されていた場合はfalseを返す．
-  どちらも指定されていない場合は，ブロックつきで呼び出されて
-  いる場合は*defaultsをyieldした結果，ブロックなしなら
-  *defaultsを返す．
-
-dir_config(target[, default_dir]) ::
-dir_config(target[, default_include, default_lib]) ::
-
-  コマンドライン上の--with-<target>-dir, --with-<target>-include,
-  --with-<target>-libのいずれかで指定されるディレクトリを
-  $CFLAGS や $LDFLAGS に追加する．--with-<target>-dir=/pathは
-  --with-<target>-include=/path/include --with-<target>-lib=/path/lib
-  と等価である．追加された include ディレクトリと lib ディレ
-  クトリの配列を返す． ([include_dir, lib_dir])
-
-pkg_config(pkg, option=nil) ::
-
-  pkg-configコマンドからパッケージpkgの情報を [cflags, ldflags, libs]
-  の配列として得る．$CFLAGS, $LDFLAGS, $libs にはそれぞれの値が
-  追加される．
-
-  pkg-configの実際のコマンドは，以下の順で試される．
-
-  1. コマンドラインで--with-{pkg}-config={command}オプションが
-     指定された場合: {command} {option}
-  2. {pkg}-config {option}
-  3. pkg-config {option} {pkg}
-
-  optionが指定された場合は、上記の配列の代わりにそのオプションを
-  指定して得られた出力をstripしたものを返す．
-
-= Appendix D. 世代別GC
-
-Ruby 2.1から世代別GCに対応しました。我々はこれをRGenGCと呼んでいます。
-RGenGCは、過去の拡張ライブラリに（ほぼ）互換性を保つように開発されている
-ため、拡張ライブラリ側の対応はほぼ不要です。
-
-ただし、対応をすることで性能を向上することができる可能性があります。もし
-拡張ライブラリに高い性能が必要である場合は対応を検討して下さい。
-
-とくにRARRAY_PTR()/RHASH_TBL()のようなマクロを用いてポインタに直接アクセ
-スするようなコードは書かないようにして下さい。代わりに、rb_ary_aref(),
-rb_ary_store() などの、適切な API 関数を利用するようにして下さい。
-
-そのほか、対応についての詳細は README.EXT の「Appendix D. Generational
-GC」を参照して下さい。
-
-/*
- * Local variables:
- * fill-column: 60
- * end:
- */
+doc/extension.ja.rdocに移動しました
diff --git a/README.ja b/README.ja
deleted file mode 100644
index 9ab2f3ca0e..0000000000
--- a/README.ja
+++ /dev/null
@@ -1,192 +0,0 @@
-= Rubyとは
-
-Rubyはシンプルかつ強力なオブジェクト指向スクリプト言語です．
-Rubyは最初から純粋なオブジェクト指向言語として設計されていま
-すから，オブジェクト指向プログラミングを手軽に行う事が出来ま
-す．もちろん通常の手続き型のプログラミングも可能です．
-
-Rubyはテキスト処理関係の能力などに優れ，Perlと同じくらい強力
-です．さらにシンプルな文法と，例外処理やイテレータなどの機構
-によって，より分かりやすいプログラミングが出来ます．
-
-
-== Rubyの特長
-
-*   シンプルな文法
-*   普通のオブジェクト指向機能(クラス，メソッドコールなど)
-*   特殊なオブジェクト指向機能(Mixin, 特異メソッドなど)
-*   演算子オーバーロード
-*   例外処理機能
-*   イテレータとクロージャ
-*   ガーベージコレクタ
-*   ダイナミックローディング (アーキテクチャによる)
-*   移植性が高い．多くのUnix-like/POSIX互換プラットフォーム上で
-    動くだけでなく，Windows， Mac OS X，BeOSなどの上でも動く
-    cf. http://bugs.ruby-lang.org/projects/ruby-trunk/wiki/SupportedPlatformsJa
-
-== 入手法
-
-=== FTPで
-
-以下の場所においてあります．
-
-ftp://ftp.ruby-lang.org/pub/ruby/
-
-=== Subversionで
-
-開発先端のソースコードは次のコマンドで取得できます．
-
-  $ svn co http://svn.ruby-lang.org/repos/ruby/trunk/ ruby
-
-他に開発中のブランチの一覧は次のコマンドで見られます．
-
-  $ svn ls http://svn.ruby-lang.org/repos/ruby/branches/
-
-=== Gitで
-
-SubversionのミラーをGitHubに公開しています．
-以下のコマンドでリポジトリを取得できます．
-
-  $ git clone git://github.com/ruby/ruby.git
-
-== ホームページ
-
-RubyのホームページのURLは
-
-http://www.ruby-lang.org/
-
-です．
-
-
-== メーリングリスト
-
-Rubyのメーリングリストがあります。参加希望の方は
-
-mailto:ruby-list-ctl@ruby-lang.org
-
-まで本文に
-
-   subscribe YourFirstName YourFamilyName
-
-と書いて送って下さい。
-
-Ruby開発者向けメーリングリストもあります。こちらではrubyのバ
-グ、将来の仕様拡張など実装上の問題について議論されています。
-参加希望の方は
-
-mailto:ruby-dev-ctl@ruby-lang.org
-
-までruby-listと同様の方法でメールしてください。
-
-Ruby拡張モジュールについて話し合うruby-extメーリングリストと
-数学関係の話題について話し合うruby-mathメーリングリストと
-英語で話し合うruby-talkメーリングリストもあります。参加方法
-はどれも同じです。
-
-
-== コンパイル・インストール
-
-以下の手順で行ってください．
-
-1.   もし +configure+ ファイルが見つからない、もしくは
-     +configure.in+ より古いようなら、 +autoconf+ を実行して
-     新しく +configure+ を生成する
-
-2.   +configure+ を実行して +Makefile+ などを生成する
-
-     環境によってはデフォルトのCコンパイラ用オプションが付き
-     ます． +configure+ オプションで <tt>optflags=..</tt> <tt>warnflags=..</tt> 等
-     で上書きできます．
-
-3.   (必要ならば)+defines.h+ を編集する
-
-     多分，必要無いと思います．
-
-4.   (必要ならば)+ext/Setup+ に静的にリンクする拡張モジュールを
-     指定する
-
-     +ext/Setup+ に記述したモジュールは静的にリンクされます．
-
-     ダイナミックローディングをサポートしていないアーキテク
-     チャでは +Setup+ の1行目の「<tt>option nodynamic</tt>」という行のコ
-     メントを外す必要があります．また，このアーキテクチャで
-     拡張モジュールを利用するためには，あらかじめ静的にリン
-     クしておく必要があります．
-
-5.   +make+ を実行してコンパイルする
-
-6.   <tt>make check</tt>でテストを行う．
-
-     「<tt>check succeeded</tt>」と表示されれば成功です．ただしテスト
-     に成功しても完璧だと保証されている訳ではありません．
-
-7.   <tt>make install</tt>
-
-     以下のディレクトリを作って，そこにファイルをインストー
-     ルします．
-
-     * <tt>${DESTDIR}${prefix}/bin</tt>
-     * <tt>${DESTDIR}${prefix}/include/ruby-${MAJOR}.${MINOR}.${TEENY}</tt>
-     * <tt>${DESTDIR}${prefix}/include/ruby-${MAJOR}.${MINOR}.${TEENY}/${PLATFORM}</tt>
-     * <tt>${DESTDIR}${prefix}/lib</tt>
-     * <tt>${DESTDIR}${prefix}/lib/ruby</tt>
-     * <tt>${DESTDIR}${prefix}/lib/ruby/${MAJOR}.${MINOR}.${TEENY}</tt>
-     * <tt>${DESTDIR}${prefix}/lib/ruby/${MAJOR}.${MINOR}.${TEENY}/${PLATFORM}</tt>
-     * <tt>${DESTDIR}${prefix}/lib/ruby/site_ruby</tt>
-     * <tt>${DESTDIR}${prefix}/lib/ruby/site_ruby/${MAJOR}.${MINOR}.${TEENY}</tt>
-     * <tt>${DESTDIR}${prefix}/lib/ruby/site_ruby/${MAJOR}.${MINOR}.${TEENY}/${PLATFORM}</tt>
-     * <tt>${DESTDIR}${prefix}/lib/ruby/vendor_ruby</tt>
-     * <tt>${DESTDIR}${prefix}/lib/ruby/vendor_ruby/${MAJOR}.${MINOR}.${TEENY}</tt>
-     * <tt>${DESTDIR}${prefix}/lib/ruby/vendor_ruby/${MAJOR}.${MINOR}.${TEENY}/${PLATFORM}</tt>
-     * <tt>${DESTDIR}${prefix}/lib/ruby/gems/${MAJOR}.${MINOR}.${TEENY}</tt>
-     * <tt>${DESTDIR}${prefix}/share/man/man1</tt>
-     * <tt>${DESTDIR}${prefix}/share/ri/${MAJOR}.${MINOR}.${TEENY}/system</tt>
-
-     RubyのAPIバージョンが'_x.y.z_'であれば，<tt>${MAJOR}</tt>は
-     '_x_'で，<tt>${MINOR}</tt>は'_y_'，<tt>${TEENY}</tt>は'_z_'です．
-
-     <b>注意</b>: APIバージョンの +teeny+ は，Rubyプログラムのバージョ
-     ンとは異なることがあります．
-
-     +root+ で作業する必要があるかもしれません．
-
-もし，コンパイル時にエラーが発生した場合にはエラーのログとマ
-シン，OSの種類を含むできるだけ詳しいレポートを作者に送ってく
-ださると他の方のためにもなります．
-
-
-== 移植
-
-UNIXであれば +configure+ がほとんどの差異を吸収してくれるはずで
-すが，思わぬ見落としがあった場合(あるに違いない)，作者にその
-ことをレポートすれば，解決できるかも知れません．
-
-アーキテクチャにもっとも依存するのはGC部です．RubyのGCは対象
-のアーキテクチャが<tt>setjmp()</tt>または<tt>getcontext()</tt>によって全てのレ
-ジスタを +jmp_buf+ や +ucontext_t+ に格納することと， +jmp_buf+ や
-+ucontext_t+ とスタックが32bitアラインメントされていることを仮定
-しています．特に前者が成立しない場合の対応は非常に困難でしょう．
-後者の解決は比較的簡単で， +gc.c+ でスタックをマークしている
-部分にアラインメントのバイト数だけずらしてマークするコードを
-追加するだけで済みます．<tt>defined(\_\_mc68000\_\_)</tt>で括られてい
-る部分を参考にしてください．
-
-レジスタウィンドウを持つCPUでは，レジスタウィンドウをスタッ
-クにフラッシュするアセンブラコードを追加する必要があるかも知
-れません．
-
-
-== 配布条件
-
-+COPYING.ja+ ファイルを参照してください。
-
-
-== 著者
-
-コメント，バグレポートその他は mailto:matz@ruby-lang.org まで．
--------------------------------------------------------
-created at: Thu Aug  3 11:57:36 JST 1995
---
-Local variables:
-mode: rdoc
-end:
diff --git a/README.ja.md b/README.ja.md
new file mode 100644
index 0000000000..93c0131690
--- /dev/null
+++ b/README.ja.md
@@ -0,0 +1,182 @@
+[![Actions Status: MinGW](https://github.com/ruby/ruby/workflows/MinGW/badge.svg)](https://github.com/ruby/ruby/actions?query=workflow%3A"MinGW")
+[![Actions Status: MJIT](https://github.com/ruby/ruby/workflows/MJIT/badge.svg)](https://github.com/ruby/ruby/actions?query=workflow%3A"MJIT")
+[![Actions Status: Ubuntu](https://github.com/ruby/ruby/workflows/Ubuntu/badge.svg)](https://github.com/ruby/ruby/actions?query=workflow%3A"Ubuntu")
+[![Actions Status: Windows](https://github.com/ruby/ruby/workflows/Windows/badge.svg)](https://github.com/ruby/ruby/actions?query=workflow%3A"Windows")
+[![AppVeyor status](https://ci.appveyor.com/api/projects/status/0sy8rrxut4o0k960/branch/master?svg=true)](https://ci.appveyor.com/project/ruby/ruby/branch/master)
+[![Travis Status](https://app.travis-ci.com/ruby/ruby.svg?branch=master)](https://app.travis-ci.com/ruby/ruby)
+
+# Rubyとは
+
+Rubyはシンプルかつ強力なオブジェクト指向スクリプト言語です． Rubyは純粋なオブジェクト指向言語として設計されているので，
+オブジェクト指向プログラミングを手軽に行う事が出来ます．もちろん普通の手続き型のプログラミングも可能です．
+
+Rubyはテキスト処理関係の能力などに優れ，Perlと同じくらい強力です．さらにシンプルな文法と，
+例外処理やイテレータなどの機構によって，より分かりやすいプログラミングが出来ます．
+
+## Rubyの特長
+
+*   シンプルな文法
+*   普通のオブジェクト指向機能(クラス，メソッドコールなど)
+*   特殊なオブジェクト指向機能(Mixin，特異メソッドなど)
+*   演算子オーバーロード
+*   例外処理機能
+*   イテレータとクロージャ
+*   ガーベージコレクタ
+*   ダイナミックローディング (アーキテクチャによる)
+*   移植性が高い．多くのUnix-like/POSIX互換プラットフォーム上で動くだけでなく，Windows， macOS，
+    Haikuなどの上でも動く cf.
+    https://github.com/ruby/ruby/blob/master/doc/contributing.rdoc#platform-maintainers
+
+
+## 入手法
+
+サードパーティーツールを使った方法を含むRubyのインストール方法の一覧は
+
+https://www.ruby-lang.org/ja/downloads/
+
+を参照してください．
+
+### Git
+
+ミラーをGitHubに公開しています． 以下のコマンドでリポジトリを取得できます．
+
+    $ git clone https://github.com/ruby/ruby.git
+
+他のブランチの一覧は次のコマンドで見られます．
+
+    $ git ls-remote https://github.com/ruby/ruby.git
+
+Rubyリポジトリの本来のmasterは https://git.ruby-lang.org/ruby.git にあります．
+コミッタはこちらを使います．
+
+### Subversion
+
+古いRubyのバージョンのソースコードは次のコマンドでも取得できます．
+
+    $ svn co https://svn.ruby-lang.org/repos/ruby/branches/ruby_2_6/ ruby
+
+他のブランチの一覧は次のコマンドで見られます．
+
+    $ svn ls https://svn.ruby-lang.org/repos/ruby/branches/
+
+
+## ホームページ
+
+RubyのホームページのURLは
+
+https://www.ruby-lang.org/
+
+です．
+
+## メーリングリスト
+
+Rubyのメーリングリストがあります．参加希望の方は [ruby-list-request@ruby-lang.org] まで本文に
+
+    subscribe
+
+と書いて送って下さい．
+
+Ruby開発者向けメーリングリストもあります．こちらではrubyのバグ，将来の仕様拡張など実装上の問題について議論されています．
+参加希望の方は [ruby-dev-request@ruby-lang.org] までruby-listと同様の方法でメールしてください．
+
+Ruby拡張モジュールについて話し合うruby-extメーリングリストと数学関係の話題について話し合うruby-mathメーリングリストと
+英語でrubyについて話し合うruby-talkメーリングリストもあります．参加方法はどれも同じです．
+
+[ruby-list-request@ruby-lang.org]: mailto:ruby-list-request@ruby-lang.org?subject=Join%20Ruby%20Mailing%20List&body=subscribe
+[ruby-dev-request@ruby-lang.org]: mailto:ruby-dev-request@ruby-lang.org?subject=Join%20Ruby%20Mailing%20List&body=subscribe
+
+## コンパイル・インストール
+
+以下の手順で行ってください．
+
+1.  (Gitリポジトリから取得したソースをビルドする場合) `./autogen.sh` を実行して新しく `configure` を生成する
+
+2.  `configure` を実行して `Makefile` などを生成する
+
+    環境によってはデフォルトのCコンパイラ用オプションが付きます． `configure` オプションで `optflags=..`
+    `warnflags=..` 等で上書きできます．
+
+3.  (必要ならば)`include/ruby/defines.h` を編集する
+
+    多分，必要無いと思います．
+
+4.  (必要ならば)`ext/Setup` に静的にリンクする拡張モジュールを指定する
+
+    `ext/Setup` に記述したモジュールは静的にリンクされます．
+
+    ダイナミックローディングをサポートしていないアーキテクチャでは `Setup` の1行目の「`option nodynamic`」という行のコ
+    メントを外す必要があります．
+    また，このアーキテクチャで拡張モジュールを利用するためには，あらかじめ静的にリンクをしておく必要があります．
+
+5.  `make` を実行してコンパイルする
+
+6.  `make check`でテストを行う．
+
+    「`check succeeded`」と表示されれば成功です．ただしテストに成功しても完璧だと保証されている訳ではありません．
+
+7.  `make install`
+
+    以下のディレクトリを作って，そこにファイルをインストー ルします．
+
+    *   `${DESTDIR}${prefix}/bin`
+    *   `${DESTDIR}${prefix}/include/ruby-${MAJOR}.${MINOR}.${TEENY}`
+    *   `${DESTDIR}${prefix}/include/ruby-${MAJOR}.${MINOR}.${TEENY}/${PLATFORM}`
+    *   `${DESTDIR}${prefix}/lib`
+    *   `${DESTDIR}${prefix}/lib/ruby`
+    *   `${DESTDIR}${prefix}/lib/ruby/${MAJOR}.${MINOR}.${TEENY}`
+    *   `${DESTDIR}${prefix}/lib/ruby/${MAJOR}.${MINOR}.${TEENY}/${PLATFORM}`
+    *   `${DESTDIR}${prefix}/lib/ruby/site_ruby`
+    *   `${DESTDIR}${prefix}/lib/ruby/site_ruby/${MAJOR}.${MINOR}.${TEENY}`
+    *   `${DESTDIR}${prefix}/lib/ruby/site_ruby/${MAJOR}.${MINOR}.${TEENY}/${PLATFORM}`
+    *   `${DESTDIR}${prefix}/lib/ruby/vendor_ruby`
+    *   `${DESTDIR}${prefix}/lib/ruby/vendor_ruby/${MAJOR}.${MINOR}.${TEENY}`
+    *   `${DESTDIR}${prefix}/lib/ruby/vendor_ruby/${MAJOR}.${MINOR}.${TEENY}/${PLATFORM}`
+    *   `${DESTDIR}${prefix}/lib/ruby/gems/${MAJOR}.${MINOR}.${TEENY}`
+    *   `${DESTDIR}${prefix}/share/man/man1`
+    *   `${DESTDIR}${prefix}/share/ri/${MAJOR}.${MINOR}.${TEENY}/system`
+
+
+    RubyのAPIバージョンが'*x.y.z*'であれば，`${MAJOR}`は
+    '*x*'で，`${MINOR}`は'*y*'，`${TEENY}`は'*z*'です．
+
+    **注意**: APIバージョンの `teeny` は，Rubyプログラムのバージョンとは異なることがあります．
+
+    `root` で作業する必要があるかもしれません．
+
+
+もし，コンパイル時にエラーが発生した場合にはエラーのログとマシン，OSの種類を含むできるだけ詳しいレポートを作者に送って下さると他の方のためにもなります．
+
+## 移植
+
+UNIXであれば `configure` がほとんどの差異を吸収してくれるはずですが，思わぬ見落としがあった場合(ある事が多い)，作者にその
+ことを報告すれば，解決できる可能性があります．
+
+アーキテクチャにもっとも依存するのはGC部です．RubyのGCは対象
+のアーキテクチャが`setjmp()`または`getcontext()`によって全てのレジスタを `jmp_buf` や `ucontext_t`
+に格納することと， `jmp_buf` や `ucontext_t` とスタックが32bitアラインメントされていることを仮定
+しています．特に前者が成立しない場合の対応は非常に困難でしょう． 後者の解決は比較的簡単で， `gc.c` でスタックをマークしている
+部分にアラインメントのバイト数だけずらしてマークするコードを追加するだけで済みます．`defined(__mc68000__)`で括られてい
+る部分を参考にしてください．
+
+レジスタウィンドウを持つCPUでは，レジスタウィンドウをスタックにフラッシュするアセンブラコードを追加する必要があるかもしれません．
+
+## 配布条件
+
+[COPYING.ja](COPYING.ja) ファイルを参照してください．
+
+## フィードバック
+
+Rubyに関する質問は [Ruby-Talk]（英語）や [Ruby-List]（日本語）や，
+[stackoverflow] などのWebサイトに投稿してください．
+
+バグ報告は https://bugs.ruby-lang.org で受け付けています．
+
+[Ruby-Talk]: https://www.ruby-lang.org/en/community/mailing-lists
+[Ruby-List]: https://www.ruby-lang.org/ja/community/mailing-lists
+[stackoverflow]: https://ja.stackoverflow.com/
+
+## 著者
+
+Rubyのオリジナル版は，1995年にまつもとゆきひろ氏によって設計・開発されました．
+
+<mailto:matz@ruby-lang.org>
diff --git a/README.md b/README.md
new file mode 100644
index 0000000000..c445448c71
--- /dev/null
+++ b/README.md
@@ -0,0 +1,91 @@
+[![Actions Status: MinGW](https://github.com/ruby/ruby/workflows/MinGW/badge.svg)](https://github.com/ruby/ruby/actions?query=workflow%3A"MinGW")
+[![Actions Status: MJIT](https://github.com/ruby/ruby/workflows/MJIT/badge.svg)](https://github.com/ruby/ruby/actions?query=workflow%3A"MJIT")
+[![Actions Status: Ubuntu](https://github.com/ruby/ruby/workflows/Ubuntu/badge.svg)](https://github.com/ruby/ruby/actions?query=workflow%3A"Ubuntu")
+[![Actions Status: Windows](https://github.com/ruby/ruby/workflows/Windows/badge.svg)](https://github.com/ruby/ruby/actions?query=workflow%3A"Windows")
+[![AppVeyor status](https://ci.appveyor.com/api/projects/status/0sy8rrxut4o0k960/branch/master?svg=true)](https://ci.appveyor.com/project/ruby/ruby/branch/master)
+[![Travis Status](https://app.travis-ci.com/ruby/ruby.svg?branch=master)](https://app.travis-ci.com/ruby/ruby)
+
+# What is Ruby?
+
+Ruby is an interpreted object-oriented programming language often
+used for web development. It also offers many scripting features
+to process plain text and serialized files, or manage system tasks.
+It is simple, straightforward, and extensible.
+
+## Features of Ruby
+
+* Simple Syntax
+* **Normal** Object-oriented Features (e.g. class, method calls)
+* **Advanced** Object-oriented Features (e.g. mix-in, singleton-method)
+* Operator Overloading
+* Exception Handling
+* Iterators and Closures
+* Garbage Collection
+* Dynamic Loading of Object Files (on some architectures)
+* Highly Portable (works on many Unix-like/POSIX compatible platforms as
+  well as Windows, macOS, etc.) cf.
+  https://github.com/ruby/ruby/blob/master/doc/maintainers.rdoc#label-Platform+Maintainers
+
+## How to get Ruby with Git
+
+For a complete list of ways to install Ruby, including using third-party tools
+like rvm, see:
+
+https://www.ruby-lang.org/en/downloads/
+
+The mirror of the Ruby source tree can be checked out with the following command:
+
+    $ git clone https://github.com/ruby/ruby.git
+
+There are some other branches under development. Try the following command
+to see the list of branches:
+
+    $ git ls-remote https://github.com/ruby/ruby.git
+
+You may also want to use https://git.ruby-lang.org/ruby.git (actual master of Ruby source)
+if you are a committer.
+
+## How to build
+
+see [Building Ruby](doc/contributing/building_ruby.md)
+
+## Ruby home page
+
+https://www.ruby-lang.org/
+
+## Documentation
+
+- [English](https://docs.ruby-lang.org/en/master/index.html)
+- [Japanese](https://docs.ruby-lang.org/ja/master/index.html)
+
+## Mailing list
+
+There is a mailing list to discuss Ruby. To subscribe to this list, please
+send the following phrase:
+
+    subscribe
+
+in the mail body (not subject) to the address [ruby-talk-request@ruby-lang.org].
+
+[ruby-talk-request@ruby-lang.org]: mailto:ruby-talk-request@ruby-lang.org?subject=Join%20Ruby%20Mailing%20List&body=subscribe
+
+## Copying
+
+See the file [COPYING](rdoc-ref:COPYING).
+
+## Feedback
+
+Questions about the Ruby language can be asked on the [Ruby-Talk](https://www.ruby-lang.org/en/community/mailing-lists) mailing list
+or on websites like https://stackoverflow.com.
+
+Bugs should be reported at https://bugs.ruby-lang.org. Read ["Reporting Issues"](https://docs.ruby-lang.org/en/master/contributing/reporting_issues_md.html) for more information.
+
+## Contributing
+
+See ["Contributing to Ruby"](https://docs.ruby-lang.org/en/master/contributing_md.html), which includes setup and build instructions.
+
+## The Author
+
+Ruby was originally designed and developed by Yukihiro Matsumoto (Matz) in 1995.
+
+<matz@ruby-lang.org>
diff --git a/aclocal.m4 b/aclocal.m4
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/aclocal.m4
diff --git a/addr2line.c b/addr2line.c
index f936694724..e5f25293e2 100644
--- a/addr2line.c
+++ b/addr2line.c
@@ -8,14 +8,26 @@
 
 **********************************************************************/
 
-#include "ruby/config.h"
+#if defined(__clang__)
+#pragma clang diagnostic ignored "-Wgnu-empty-initializer"
+#pragma clang diagnostic ignored "-Wgcc-compat"
+#endif
+
+#include "ruby/internal/config.h"
+#include "ruby/defines.h"
 #include "ruby/missing.h"
 #include "addr2line.h"
 
 #include <stdio.h>
 #include <errno.h>
 
-#ifdef USE_ELF
+#ifdef HAVE_LIBPROC_H
+#include <libproc.h>
+#endif
+
+#include "ruby/internal/stdbool.h"
+
+#if defined(USE_ELF) || defined(HAVE_MACH_O_LOADER_H)
 
 #include <fcntl.h>
 #include <limits.h>
@@ -28,19 +40,11 @@
 #include <sys/stat.h>
 #include <unistd.h>
 
-#ifdef __OpenBSD__
-#include <elf_abi.h>
-#else
-#include <elf.h>
-#endif
-
 /* Make alloca work the best possible way.  */
 #ifdef __GNUC__
-# ifndef atarist
-#  ifndef alloca
-#   define alloca __builtin_alloca
-#  endif
-# endif	/* atarist */
+# ifndef alloca
+#  define alloca __builtin_alloca
+# endif
 #else
 # ifdef HAVE_ALLOCA_H
 #  include <alloca.h>
@@ -55,11 +59,53 @@ void *alloca();
 # endif	/* HAVE_ALLOCA_H */
 #endif /* __GNUC__ */
 
-#ifdef HAVE_DL_ITERATE_PHDR
-# ifndef _GNU_SOURCE
-#  define _GNU_SOURCE
+#ifdef HAVE_DLADDR
+# include <dlfcn.h>
+#endif
+
+#ifdef HAVE_MACH_O_LOADER_H
+# include <crt_externs.h>
+# include <mach-o/fat.h>
+# include <mach-o/loader.h>
+# include <mach-o/nlist.h>
+# include <mach-o/stab.h>
+#endif
+
+#ifdef USE_ELF
+# ifdef __OpenBSD__
+#  include <elf_abi.h>
+# else
+#  include <elf.h>
+# endif
+
+#ifndef ElfW
+# if SIZEOF_VOIDP == 8
+#  define ElfW(x) Elf64##_##x
+# else
+#  define ElfW(x) Elf32##_##x
+# endif
+#endif
+#ifndef ELF_ST_TYPE
+# if SIZEOF_VOIDP == 8
+#  define ELF_ST_TYPE ELF64_ST_TYPE
+# else
+#  define ELF_ST_TYPE ELF32_ST_TYPE
+# endif
+#endif
+#endif
+
+#ifdef SHF_COMPRESSED
+# if defined(ELFCOMPRESS_ZLIB) && defined(HAVE_LIBZ)
+   /* FreeBSD 11.0 lacks ELFCOMPRESS_ZLIB */
+#  include <zlib.h>
+#  define SUPPORT_COMPRESSED_DEBUG_LINE
 # endif
-# include <link.h>
+#else /* compatibility with glibc < 2.22 */
+# define SHF_COMPRESSED 0
+#endif
+
+#ifndef PATH_MAX
+#define PATH_MAX 4096
 #endif
 
 #define DW_LNS_copy                     0x01
@@ -81,40 +127,83 @@ void *alloca();
 #define DW_LNE_define_file              0x03
 #define DW_LNE_set_discriminator        0x04  /* DWARF4 */
 
-#ifndef ElfW
-# if SIZEOF_VOIDP == 8
-#  define ElfW(x) Elf64##_##x
-# else
-#  define ElfW(x) Elf32##_##x
-# endif
-#endif
-#ifndef PATH_MAX
-#define PATH_MAX 4096
-#endif
-
-int kprintf(const char *fmt, ...);
+PRINTF_ARGS(static int kprintf(const char *fmt, ...), 1, 2);
 
-typedef struct {
+typedef struct line_info {
     const char *dirname;
     const char *filename;
+    const char *path; /* object path */
     int line;
 
-    int fd;
-    void *mapped;
-    size_t mapped_size;
-    unsigned long base_addr;
+    uintptr_t base_addr;
+    uintptr_t saddr;
+    const char *sname; /* function name */
+
+    struct line_info *next;
 } line_info_t;
 
+struct dwarf_section {
+    char *ptr;
+    size_t size;
+    uint64_t flags;
+};
+
+typedef struct obj_info {
+    const char *path; /* object path */
+    char *mapped;
+    size_t mapped_size;
+    void *uncompressed;
+    uintptr_t base_addr;
+    uintptr_t vmaddr;
+    struct dwarf_section debug_abbrev;
+    struct dwarf_section debug_info;
+    struct dwarf_section debug_line;
+    struct dwarf_section debug_ranges;
+    struct dwarf_section debug_str_offsets;
+    struct dwarf_section debug_addr;
+    struct dwarf_section debug_rnglists;
+    struct dwarf_section debug_str;
+    struct dwarf_section debug_line_str;
+    struct obj_info *next;
+} obj_info_t;
+
+#define DWARF_SECTION_COUNT 9
+
+static struct dwarf_section *
+obj_dwarf_section_at(obj_info_t *obj, int n)
+{
+    struct dwarf_section *ary[] = {
+        &obj->debug_abbrev,
+        &obj->debug_info,
+        &obj->debug_line,
+        &obj->debug_ranges,
+        &obj->debug_str_offsets,
+        &obj->debug_addr,
+        &obj->debug_rnglists,
+        &obj->debug_str,
+        &obj->debug_line_str
+    };
+    if (n < 0 || DWARF_SECTION_COUNT <= n) {
+        abort();
+    }
+    return ary[n];
+}
+
+struct debug_section_definition {
+    const char *name;
+    struct dwarf_section *dwarf;
+};
+
 /* Avoid consuming stack as this module may be used from signal handler */
-static char binary_filename[PATH_MAX];
+static char binary_filename[PATH_MAX + 1];
 
 static unsigned long
-uleb128(char **p)
+uleb128(const char **p)
 {
     unsigned long r = 0;
     int s = 0;
     for (;;) {
-	unsigned char b = *(unsigned char *)(*p)++;
+	unsigned char b = (unsigned char)*(*p)++;
 	if (b < 0x80) {
 	    r += (unsigned long)b << s;
 	    break;
@@ -126,12 +215,12 @@ uleb128(char **p)
 }
 
 static long
-sleb128(char **p)
+sleb128(const char **p)
 {
     long r = 0;
     int s = 0;
     for (;;) {
-	unsigned char b = *(unsigned char *)(*p)++;
+	unsigned char b = (unsigned char)*(*p)++;
 	if (b < 0x80) {
 	    if (b & 0x40) {
 		r -= (0x80 - b) << s;
@@ -148,7 +237,7 @@ sleb128(char **p)
 }
 
 static const char *
-get_nth_dirname(unsigned long dir, char *p)
+get_nth_dirname(unsigned long dir, const char *p)
 {
     if (!dir--) {
 	return "";
@@ -165,155 +254,191 @@ get_nth_dirname(unsigned long dir, char *p)
     return p;
 }
 
+static const char *parse_ver5_debug_line_header(const char *p, int idx, uint8_t format, obj_info_t *obj, const char **out_path, uint64_t *out_directory_index);
+
 static void
-fill_filename(int file, char *include_directories, char *filenames,
-	      line_info_t *line)
+fill_filename(int file, uint8_t format, uint16_t version, const char *include_directories, const char *filenames, line_info_t *line, obj_info_t *obj)
 {
     int i;
-    char *p = filenames;
-    char *filename;
+    const char *p = filenames;
+    const char *filename;
     unsigned long dir;
-    for (i = 1; i <= file; i++) {
-	filename = p;
-	if (!*p) {
-	    /* Need to output binary file name? */
-	    kprintf("Unexpected file number %d in %s\n",
-		    file, binary_filename);
-	    return;
-	}
-	while (*p) p++;
-	p++;
-	dir = uleb128(&p);
-	/* last modified. */
-	uleb128(&p);
-	/* size of the file. */
-	uleb128(&p);
-
-	if (i == file) {
-	    line->filename = filename;
-	    line->dirname = get_nth_dirname(dir, include_directories);
-	}
-    }
-}
-
-static int
-get_path_from_symbol(const char *symbol, const char **p, size_t *len)
-{
-    if (symbol[0] == '0') {
-	/* libexecinfo */
-	*p   = strchr(symbol, '/');
-	if (*p == NULL) return 0;
-	*len = strlen(*p);
+    if (version >= 5) {
+        const char *path;
+        uint64_t directory_index = -1;
+        parse_ver5_debug_line_header(filenames, file, format, obj, &path, &directory_index);
+        line->filename = path;
+        parse_ver5_debug_line_header(include_directories, (int)directory_index, format, obj, &path, NULL);
+        line->dirname = path;
     }
     else {
-	/* glibc */
-	const char *q;
-	*p   = symbol;
-	q   = strchr(symbol, '(');
-	if (q == NULL) return 0;
-	*len = q - symbol;
+        for (i = 1; i <= file; i++) {
+            filename = p;
+            if (!*p) {
+                /* Need to output binary file name? */
+                kprintf("Unexpected file number %d in %s at %tx\n",
+                        file, binary_filename, filenames - obj->mapped);
+                return;
+            }
+            while (*p) p++;
+            p++;
+            dir = uleb128(&p);
+            /* last modified. */
+            uleb128(&p);
+            /* size of the file. */
+            uleb128(&p);
+
+            if (i == file) {
+                line->filename = filename;
+                line->dirname = get_nth_dirname(dir, include_directories);
+            }
+        }
     }
-    return 1;
 }
 
 static void
-fill_line(int num_traces, void **traces,
-	  unsigned long addr, int file, int line,
-	  char *include_directories, char *filenames, line_info_t *lines)
+fill_line(int num_traces, void **traces, uintptr_t addr, int file, int line,
+	  uint8_t format, uint16_t version, const char *include_directories, const char *filenames,
+	  obj_info_t *obj, line_info_t *lines, int offset)
 {
     int i;
-    for (i = 0; i < num_traces; i++) {
-	unsigned long a = (unsigned long)traces[i] - lines[i].base_addr;
+    addr += obj->base_addr - obj->vmaddr;
+    for (i = offset; i < num_traces; i++) {
+	uintptr_t a = (uintptr_t)traces[i];
 	/* We assume one line code doesn't result >100 bytes of native code.
        We may want more reliable way eventually... */
 	if (addr < a && a < addr + 100) {
-	    fill_filename(file, include_directories, filenames, &lines[i]);
+	    fill_filename(file, format, version, include_directories, filenames, &lines[i], obj);
 	    lines[i].line = line;
 	}
     }
 }
 
-static void
-parse_debug_line_cu(int num_traces, void **traces,
-		    char **debug_line, line_info_t *lines)
+struct LineNumberProgramHeader {
+    uint64_t unit_length;
+    uint16_t version;
+    uint8_t format; /* 4 or 8 */
+    uint64_t header_length;
+    uint8_t minimum_instruction_length;
+    uint8_t maximum_operations_per_instruction;
+    uint8_t default_is_stmt;
+    int8_t line_base;
+    uint8_t line_range;
+    uint8_t opcode_base;
+    /* uint8_t standard_opcode_lengths[opcode_base-1]; */
+    const char *include_directories;
+    const char *filenames;
+    const char *cu_start;
+    const char *cu_end;
+};
+
+static int
+parse_debug_line_header(obj_info_t *obj, const char **pp, struct LineNumberProgramHeader *header)
 {
-    char *p, *cu_end, *cu_start, *include_directories, *filenames;
-    unsigned long unit_length;
-    int default_is_stmt, line_base;
-    unsigned int header_length, minimum_instruction_length, line_range,
-		 opcode_base;
-    /* unsigned char *standard_opcode_lengths; */
+    const char *p = *pp;
+    header->unit_length = *(uint32_t *)p;
+    p += sizeof(uint32_t);
+
+    header->format = 4;
+    if (header->unit_length == 0xffffffff) {
+	header->unit_length = *(uint64_t *)p;
+	p += sizeof(uint64_t);
+        header->format = 8;
+    }
 
-    /* The registers. */
-    unsigned long addr = 0;
-    unsigned int file = 1;
-    unsigned int line = 1;
-    /* unsigned int column = 0; */
-    int is_stmt;
-    /* int basic_block = 0; */
-    /* int end_sequence = 0; */
-    /* int prologue_end = 0; */
-    /* int epilogue_begin = 0; */
-    /* unsigned int isa = 0; */
+    header->cu_end = p + header->unit_length;
 
-    p = *debug_line;
+    header->version = *(uint16_t *)p;
+    p += sizeof(uint16_t);
+    if (header->version > 5) return -1;
 
-    unit_length = *(unsigned int *)p;
-    p += sizeof(unsigned int);
-    if (unit_length == 0xffffffff) {
-	unit_length = *(unsigned long *)p;
-	p += sizeof(unsigned long);
+    if (header->version >= 5) {
+        /* address_size = *(uint8_t *)p++; */
+        /* segment_selector_size = *(uint8_t *)p++; */
+        p += 2;
     }
 
-    cu_end = p + unit_length;
-
-    /*dwarf_version = *(unsigned short *)p;*/
-    p += 2;
+    header->header_length = header->format == 4 ? *(uint32_t *)p : *(uint64_t *)p;
+    p += header->format;
+    header->cu_start = p + header->header_length;
 
-    header_length = *(unsigned int *)p;
-    p += sizeof(unsigned int);
+    header->minimum_instruction_length = *(uint8_t *)p++;
 
-    cu_start = p + header_length;
-
-    minimum_instruction_length = *(unsigned char *)p;
-    p++;
+    if (header->version >= 4) {
+        /* maximum_operations_per_instruction = *(uint8_t *)p; */
+        if (*p != 1) return -1; /* For non-VLIW architectures, this field is 1 */
+        p++;
+    }
 
-    is_stmt = default_is_stmt = *(unsigned char *)p;
-    p++;
+    header->default_is_stmt = *(uint8_t *)p++;
+    header->line_base = *(int8_t *)p++;
+    header->line_range = *(uint8_t *)p++;
+    header->opcode_base = *(uint8_t *)p++;
+    /* header->standard_opcode_lengths = (uint8_t *)p - 1; */
+    p += header->opcode_base - 1;
+
+    if (header->version >= 5) {
+        header->include_directories = p;
+        p = parse_ver5_debug_line_header(p, -1, header->format, obj, NULL, NULL);
+        header->filenames = p;
+    }
+    else {
+        header->include_directories = p;
 
-    line_base = *(char *)p;
-    p++;
+        /* temporary measure for compress-debug-sections */
+        if (p >= header->cu_end) return -1;
 
-    line_range = *(unsigned char *)p;
-    p++;
+        /* skip include directories */
+        while (*p) {
+            p = memchr(p, '\0', header->cu_end - p);
+            if (!p) return -1;
+            p++;
+        }
+        p++;
 
-    opcode_base = *(unsigned char *)p;
-    p++;
+        header->filenames = p;
+    }
 
-    /* standard_opcode_lengths = (unsigned char *)p - 1; */
-    p += opcode_base - 1;
+    *pp = header->cu_start;
 
-    include_directories = p;
+    return 0;
+}
 
-    /* skip include directories */
-    while (*p) {
-	while (*p) p++;
-	p++;
-    }
-    p++;
+static int
+parse_debug_line_cu(int num_traces, void **traces, const char **debug_line,
+		obj_info_t *obj, line_info_t *lines, int offset)
+{
+    const char *p = (const char *)*debug_line;
+    struct LineNumberProgramHeader header;
 
-    filenames = p;
+    /* The registers. */
+    unsigned long addr = 0;
+    unsigned int file = 1;
+    unsigned int line = 1;
+    /* unsigned int column = 0; */
+    int is_stmt;
+    /* int basic_block = 0; */
+    /* int end_sequence = 0; */
+    /* int prologue_end = 0; */
+    /* int epilogue_begin = 0; */
+    /* unsigned int isa = 0; */
 
-    p = cu_start;
+    if (parse_debug_line_header(obj, &p, &header))
+        return -1;
+    is_stmt = header.default_is_stmt;
 
 #define FILL_LINE()						    \
     do {							    \
 	fill_line(num_traces, traces, addr, file, line,		    \
-		  include_directories, filenames, lines);	    \
+                  header.format,                                    \
+                  header.version,                                   \
+                  header.include_directories,                       \
+                  header.filenames,                                 \
+		  obj, lines, offset);				    \
 	/*basic_block = prologue_end = epilogue_begin = 0;*/	    \
     } while (0)
 
-    while (p < cu_end) {
+    while (p < header.cu_end) {
 	unsigned long a;
 	unsigned char op = *p++;
 	switch (op) {
@@ -321,7 +446,7 @@ parse_debug_line_cu(int num_traces, void **traces,
 	    FILL_LINE();
 	    break;
 	case DW_LNS_advance_pc:
-	    a = uleb128(&p);
+	    a = uleb128(&p) * header.minimum_instruction_length;
 	    addr += a;
 	    break;
 	case DW_LNS_advance_line: {
@@ -342,12 +467,13 @@ parse_debug_line_cu(int num_traces, void **traces,
 	    /*basic_block = 1; */
 	    break;
 	case DW_LNS_const_add_pc:
-	    a = ((255 - opcode_base) / line_range) *
-		minimum_instruction_length;
+	    a = ((255UL - header.opcode_base) / header.line_range) *
+		header.minimum_instruction_length;
 	    addr += a;
 	    break;
 	case DW_LNS_fixed_advance_pc:
-	    a = *(unsigned char *)p++;
+	    a = *(uint16_t *)p;
+	    p += sizeof(uint16_t);
 	    addr += a;
 	    break;
 	case DW_LNS_set_prologue_end:
@@ -360,7 +486,7 @@ parse_debug_line_cu(int num_traces, void **traces,
 	    /* isa = (unsigned int)*/(void)uleb128(&p);
 	    break;
 	case 0:
-	    a = *(unsigned char *)p++;
+	    a = uleb128(&p);
 	    op = *p++;
 	    switch (op) {
 	    case DW_LNE_end_sequence:
@@ -370,7 +496,7 @@ parse_debug_line_cu(int num_traces, void **traces,
 		file = 1;
 		line = 1;
 		/* column = 0; */
-		is_stmt = default_is_stmt;
+		is_stmt = header.default_is_stmt;
 		/* end_sequence = 0; */
 		/* isa = 0; */
 		break;
@@ -392,48 +518,74 @@ parse_debug_line_cu(int num_traces, void **traces,
 	    }
 	    break;
 	default: {
-	    unsigned long addr_incr;
-	    unsigned long line_incr;
-	    a = op - opcode_base;
-	    addr_incr = (a / line_range) * minimum_instruction_length;
-	    line_incr = line_base + (a % line_range);
-	    addr += (unsigned int)addr_incr;
-	    line += (unsigned int)line_incr;
+            uint8_t adjusted_opcode = op - header.opcode_base;
+            uint8_t operation_advance = adjusted_opcode / header.line_range;
+            /* NOTE: this code doesn't support VLIW */
+            addr += operation_advance * header.minimum_instruction_length;
+            line += header.line_base + (adjusted_opcode % header.line_range);
 	    FILL_LINE();
 	}
 	}
     }
-    *debug_line = p;
+    *debug_line = (char *)p;
+    return 0;
 }
 
-static void
+static int
 parse_debug_line(int num_traces, void **traces,
-		 char *debug_line, unsigned long size, line_info_t *lines)
+		 const char *debug_line, unsigned long size,
+		 obj_info_t *obj, line_info_t *lines, int offset)
 {
-    char *debug_line_end = debug_line + size;
+    const char *debug_line_end = debug_line + size;
     while (debug_line < debug_line_end) {
-	parse_debug_line_cu(num_traces, traces, &debug_line, lines);
+	if (parse_debug_line_cu(num_traces, traces, &debug_line, obj, lines, offset))
+	    return -1;
     }
     if (debug_line != debug_line_end) {
 	kprintf("Unexpected size of .debug_line in %s\n",
 		binary_filename);
     }
+    return 0;
 }
 
 /* read file and fill lines */
+static uintptr_t
+fill_lines(int num_traces, void **traces, int check_debuglink,
+	   obj_info_t **objp, line_info_t *lines, int offset);
+
 static void
-fill_lines(int num_traces, void **traces, char **syms, int check_debuglink,
-	   line_info_t *current_line, line_info_t *lines);
+append_obj(obj_info_t **objp)
+{
+    obj_info_t *newobj = calloc(1, sizeof(obj_info_t));
+    if (*objp) (*objp)->next = newobj;
+    *objp = newobj;
+}
+
+#ifdef USE_ELF
+/* Ideally we should check 4 paths to follow gnu_debuglink:
+ *
+ *   - /usr/lib/debug/.build-id/ab/cdef1234.debug
+ *   - /usr/bin/ruby.debug
+ *   - /usr/bin/.debug/ruby.debug
+ *   - /usr/lib/debug/usr/bin/ruby.debug.
+ *
+ * but we handle only two cases for now as the two formats are
+ * used by some linux distributions.
+ *
+ * See GDB's info for detail.
+ * https://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html
+ */
 
+// check the path pattern of "/usr/lib/debug/usr/bin/ruby.debug"
 static void
-follow_debuglink(char *debuglink, int num_traces, void **traces, char **syms,
-		 line_info_t *current_line, line_info_t *lines)
+follow_debuglink(const char *debuglink, int num_traces, void **traces,
+		 obj_info_t **objp, line_info_t *lines, int offset)
 {
-    /* Ideally we should check 4 paths to follow gnu_debuglink,
-       but we handle only one case for now as this format is used
-       by some linux distributions. See GDB's info for detail. */
     static const char global_debug_dir[] = "/usr/lib/debug";
-    char *p, *subdir;
+    const size_t global_debug_dir_len = sizeof(global_debug_dir) - 1;
+    char *p;
+    obj_info_t *o1 = *objp, *o2;
+    size_t len;
 
     p = strrchr(binary_filename, '/');
     if (!p) {
@@ -441,50 +593,1448 @@ follow_debuglink(char *debuglink, int num_traces, void **traces, char **syms,
     }
     p[1] = '\0';
 
-    subdir = (char *)alloca(strlen(binary_filename) + 1);
-    strcpy(subdir, binary_filename);
-    strcpy(binary_filename, global_debug_dir);
-    strncat(binary_filename, subdir,
-	    PATH_MAX - strlen(binary_filename) - 1);
-    strncat(binary_filename, debuglink,
-	    PATH_MAX - strlen(binary_filename) - 1);
+    len = strlen(binary_filename);
+    if (len >= PATH_MAX - global_debug_dir_len)
+	len = PATH_MAX - global_debug_dir_len - 1;
+    memmove(binary_filename + global_debug_dir_len, binary_filename, len);
+    memcpy(binary_filename, global_debug_dir, global_debug_dir_len);
+    len += global_debug_dir_len;
+    strlcpy(binary_filename + len, debuglink, PATH_MAX - len);
+
+    append_obj(objp);
+    o2 = *objp;
+    o2->base_addr = o1->base_addr;
+    o2->path = o1->path;
+    fill_lines(num_traces, traces, 0, objp, lines, offset);
+}
+
+// check the path pattern of "/usr/lib/debug/.build-id/ab/cdef1234.debug"
+static void
+follow_debuglink_build_id(const char *build_id, size_t build_id_size, int num_traces, void **traces,
+                          obj_info_t **objp, line_info_t *lines, int offset)
+{
+    static const char global_debug_dir[] = "/usr/lib/debug/.build-id/";
+    const size_t global_debug_dir_len = sizeof(global_debug_dir) - 1;
+    char *p;
+    obj_info_t *o1 = *objp, *o2;
+    size_t i;
+
+    if (PATH_MAX < global_debug_dir_len + 1 + build_id_size * 2 + 6) return;
+
+    memcpy(binary_filename, global_debug_dir, global_debug_dir_len);
+    p = binary_filename + global_debug_dir_len;
+    for (i = 0; i < build_id_size; i++) {
+        static const char tbl[] = "0123456789abcdef";
+        unsigned char n = build_id[i];
+        *p++ = tbl[n / 16];
+        *p++ = tbl[n % 16];
+        if (i == 0) *p++ = '/';
+    }
+    strcpy(p, ".debug");
 
-    munmap(current_line->mapped, current_line->mapped_size);
-    close(current_line->fd);
-    fill_lines(num_traces, traces, syms, 0, current_line, lines);
+    append_obj(objp);
+    o2 = *objp;
+    o2->base_addr = o1->base_addr;
+    o2->path = o1->path;
+    fill_lines(num_traces, traces, 0, objp, lines, offset);
+}
+#endif
+
+enum
+{
+    DW_TAG_compile_unit = 0x11,
+    DW_TAG_inlined_subroutine = 0x1d,
+    DW_TAG_subprogram = 0x2e,
+};
+
+/* Attributes encodings */
+enum
+{
+    DW_AT_sibling = 0x01,
+    DW_AT_location = 0x02,
+    DW_AT_name = 0x03,
+    /* Reserved 0x04 */
+    /* Reserved 0x05 */
+    /* Reserved 0x06 */
+    /* Reserved 0x07 */
+    /* Reserved 0x08 */
+    DW_AT_ordering = 0x09,
+    /* Reserved 0x0a */
+    DW_AT_byte_size = 0x0b,
+    /* Reserved 0x0c */
+    DW_AT_bit_size = 0x0d,
+    /* Reserved 0x0e */
+    /* Reserved 0x0f */
+    DW_AT_stmt_list = 0x10,
+    DW_AT_low_pc = 0x11,
+    DW_AT_high_pc = 0x12,
+    DW_AT_language = 0x13,
+    /* Reserved 0x14 */
+    DW_AT_discr = 0x15,
+    DW_AT_discr_value = 0x16,
+    DW_AT_visibility = 0x17,
+    DW_AT_import = 0x18,
+    DW_AT_string_length = 0x19,
+    DW_AT_common_reference = 0x1a,
+    DW_AT_comp_dir = 0x1b,
+    DW_AT_const_value = 0x1c,
+    DW_AT_containing_type = 0x1d,
+    DW_AT_default_value = 0x1e,
+    /* Reserved 0x1f */
+    DW_AT_inline = 0x20,
+    DW_AT_is_optional = 0x21,
+    DW_AT_lower_bound = 0x22,
+    /* Reserved 0x23 */
+    /* Reserved 0x24 */
+    DW_AT_producer = 0x25,
+    /* Reserved 0x26 */
+    DW_AT_prototyped = 0x27,
+    /* Reserved 0x28 */
+    /* Reserved 0x29 */
+    DW_AT_return_addr = 0x2a,
+    /* Reserved 0x2b */
+    DW_AT_start_scope = 0x2c,
+    /* Reserved 0x2d */
+    DW_AT_bit_stride = 0x2e,
+    DW_AT_upper_bound = 0x2f,
+    /* Reserved 0x30 */
+    DW_AT_abstract_origin = 0x31,
+    DW_AT_accessibility = 0x32,
+    DW_AT_address_class = 0x33,
+    DW_AT_artificial = 0x34,
+    DW_AT_base_types = 0x35,
+    DW_AT_calling_convention = 0x36,
+    DW_AT_count = 0x37,
+    DW_AT_data_member_location = 0x38,
+    DW_AT_decl_column = 0x39,
+    DW_AT_decl_file = 0x3a,
+    DW_AT_decl_line = 0x3b,
+    DW_AT_declaration = 0x3c,
+    DW_AT_discr_list = 0x3d,
+    DW_AT_encoding = 0x3e,
+    DW_AT_external = 0x3f,
+    DW_AT_frame_base = 0x40,
+    DW_AT_friend = 0x41,
+    DW_AT_identifier_case = 0x42,
+    /* Reserved 0x43 */
+    DW_AT_namelist_item = 0x44,
+    DW_AT_priority = 0x45,
+    DW_AT_segment = 0x46,
+    DW_AT_specification = 0x47,
+    DW_AT_static_link = 0x48,
+    DW_AT_type = 0x49,
+    DW_AT_use_location = 0x4a,
+    DW_AT_variable_parameter = 0x4b,
+    DW_AT_virtuality = 0x4c,
+    DW_AT_vtable_elem_location = 0x4d,
+    DW_AT_allocated = 0x4e,
+    DW_AT_associated = 0x4f,
+    DW_AT_data_location = 0x50,
+    DW_AT_byte_stride = 0x51,
+    DW_AT_entry_pc = 0x52,
+    DW_AT_use_UTF8 = 0x53,
+    DW_AT_extension = 0x54,
+    DW_AT_ranges = 0x55,
+    DW_AT_trampoline = 0x56,
+    DW_AT_call_column = 0x57,
+    DW_AT_call_file = 0x58,
+    DW_AT_call_line = 0x59,
+    DW_AT_description = 0x5a,
+    DW_AT_binary_scale = 0x5b,
+    DW_AT_decimal_scale = 0x5c,
+    DW_AT_small = 0x5d,
+    DW_AT_decimal_sign = 0x5e,
+    DW_AT_digit_count = 0x5f,
+    DW_AT_picture_string = 0x60,
+    DW_AT_mutable = 0x61,
+    DW_AT_threads_scaled = 0x62,
+    DW_AT_explicit = 0x63,
+    DW_AT_object_pointer = 0x64,
+    DW_AT_endianity = 0x65,
+    DW_AT_elemental = 0x66,
+    DW_AT_pure = 0x67,
+    DW_AT_recursive = 0x68,
+    DW_AT_signature = 0x69,
+    DW_AT_main_subprogram = 0x6a,
+    DW_AT_data_bit_offset = 0x6b,
+    DW_AT_const_expr = 0x6c,
+    DW_AT_enum_class = 0x6d,
+    DW_AT_linkage_name = 0x6e,
+    DW_AT_string_length_bit_size = 0x6f,
+    DW_AT_string_length_byte_size = 0x70,
+    DW_AT_rank = 0x71,
+    DW_AT_str_offsets_base = 0x72,
+    DW_AT_addr_base = 0x73,
+    DW_AT_rnglists_base = 0x74,
+    /* Reserved 0x75 */
+    DW_AT_dwo_name = 0x76,
+    DW_AT_reference = 0x77,
+    DW_AT_rvalue_reference = 0x78,
+    DW_AT_macros = 0x79,
+    DW_AT_call_all_calls = 0x7a,
+    DW_AT_call_all_source_calls = 0x7b,
+    DW_AT_call_all_tail_calls = 0x7c,
+    DW_AT_call_return_pc = 0x7d,
+    DW_AT_call_value = 0x7e,
+    DW_AT_call_origin = 0x7f,
+    DW_AT_call_parameter = 0x80,
+    DW_AT_call_pc = 0x81,
+    DW_AT_call_tail_call = 0x82,
+    DW_AT_call_target = 0x83,
+    DW_AT_call_target_clobbered = 0x84,
+    DW_AT_call_data_location = 0x85,
+    DW_AT_call_data_value = 0x86,
+    DW_AT_noreturn = 0x87,
+    DW_AT_alignment = 0x88,
+    DW_AT_export_symbols = 0x89,
+    DW_AT_deleted = 0x8a,
+    DW_AT_defaulted = 0x8b,
+    DW_AT_loclists_base = 0x8c,
+    DW_AT_lo_user = 0x2000,
+    DW_AT_hi_user = 0x3fff
+};
+
+/* Attribute form encodings */
+enum
+{
+    DW_FORM_addr = 0x01,
+    /* Reserved 0x02 */
+    DW_FORM_block2 = 0x03,
+    DW_FORM_block4 = 0x04,
+    DW_FORM_data2 = 0x05,
+    DW_FORM_data4 = 0x06,
+    DW_FORM_data8 = 0x07,
+    DW_FORM_string = 0x08,
+    DW_FORM_block = 0x09,
+    DW_FORM_block1 = 0x0a,
+    DW_FORM_data1 = 0x0b,
+    DW_FORM_flag = 0x0c,
+    DW_FORM_sdata = 0x0d,
+    DW_FORM_strp = 0x0e,
+    DW_FORM_udata = 0x0f,
+    DW_FORM_ref_addr = 0x10,
+    DW_FORM_ref1 = 0x11,
+    DW_FORM_ref2 = 0x12,
+    DW_FORM_ref4 = 0x13,
+    DW_FORM_ref8 = 0x14,
+    DW_FORM_ref_udata = 0x15,
+    DW_FORM_indirect = 0x16,
+    DW_FORM_sec_offset = 0x17,
+    DW_FORM_exprloc = 0x18,
+    DW_FORM_flag_present = 0x19,
+    DW_FORM_strx = 0x1a,
+    DW_FORM_addrx = 0x1b,
+    DW_FORM_ref_sup4 = 0x1c,
+    DW_FORM_strp_sup = 0x1d,
+    DW_FORM_data16 = 0x1e,
+    DW_FORM_line_strp = 0x1f,
+    DW_FORM_ref_sig8 = 0x20,
+    DW_FORM_implicit_const = 0x21,
+    DW_FORM_loclistx = 0x22,
+    DW_FORM_rnglistx = 0x23,
+    DW_FORM_ref_sup8 = 0x24,
+    DW_FORM_strx1 = 0x25,
+    DW_FORM_strx2 = 0x26,
+    DW_FORM_strx3 = 0x27,
+    DW_FORM_strx4 = 0x28,
+    DW_FORM_addrx1 = 0x29,
+    DW_FORM_addrx2 = 0x2a,
+    DW_FORM_addrx3 = 0x2b,
+    DW_FORM_addrx4 = 0x2c
+};
+
+/* Range list entry encodings */
+enum {
+    DW_RLE_end_of_list = 0x00,
+    DW_RLE_base_addressx = 0x01,
+    DW_RLE_startx_endx = 0x02,
+    DW_RLE_startx_length = 0x03,
+    DW_RLE_offset_pair = 0x04,
+    DW_RLE_base_address = 0x05,
+    DW_RLE_start_end = 0x06,
+    DW_RLE_start_length = 0x07
+};
+
+enum {
+    VAL_none = 0,
+    VAL_cstr = 1,
+    VAL_data = 2,
+    VAL_uint = 3,
+    VAL_int = 4,
+    VAL_addr = 5
+};
+
+# define ABBREV_TABLE_SIZE 256
+typedef struct {
+    obj_info_t *obj;
+    const char *file;
+    uint8_t current_version;
+    const char *current_cu;
+    uint64_t current_low_pc;
+    uint64_t current_str_offsets_base;
+    uint64_t current_addr_base;
+    uint64_t current_rnglists_base;
+    const char *debug_line_cu_end;
+    uint8_t debug_line_format;
+    uint16_t debug_line_version;
+    const char *debug_line_files;
+    const char *debug_line_directories;
+    const char *p;
+    const char *cu_end;
+    const char *pend;
+    const char *q0;
+    const char *q;
+    int format; // 4 or 8
+    uint8_t address_size;
+    int level;
+    const char *abbrev_table[ABBREV_TABLE_SIZE];
+} DebugInfoReader;
+
+typedef struct {
+    ptrdiff_t pos;
+    int tag;
+    int has_children;
+} DIE;
+
+typedef struct {
+    union {
+        const char *ptr;
+        uint64_t uint64;
+        int64_t int64;
+        uint64_t addr_idx;
+    } as;
+    uint64_t off;
+    uint64_t at;
+    uint64_t form;
+    size_t size;
+    int type;
+} DebugInfoValue;
+
+#if defined(WORDS_BIGENDIAN)
+#define MERGE_2INTS(a,b,sz) (((uint64_t)(a)<<sz)|(b))
+#else
+#define MERGE_2INTS(a,b,sz) (((uint64_t)(b)<<sz)|(a))
+#endif
+
+static uint16_t
+get_uint16(const uint8_t *p)
+{
+    return (uint16_t)MERGE_2INTS(p[0],p[1],8);
+}
+
+static uint32_t
+get_uint32(const uint8_t *p)
+{
+    return (uint32_t)MERGE_2INTS(get_uint16(p),get_uint16(p+2),16);
+}
+
+static uint64_t
+get_uint64(const uint8_t *p)
+{
+    return MERGE_2INTS(get_uint32(p),get_uint32(p+4),32);
+}
+
+static uint8_t
+read_uint8(const char **ptr)
+{
+    const char *p = *ptr;
+    *ptr = (p + 1);
+    return (uint8_t)*p;
+}
+
+static uint16_t
+read_uint16(const char **ptr)
+{
+    const char *p = *ptr;
+    *ptr = (p + 2);
+    return get_uint16((const uint8_t *)p);
+}
+
+static uint32_t
+read_uint24(const char **ptr)
+{
+    const char *p = *ptr;
+    *ptr = (p + 3);
+    return ((uint8_t)*p << 16) | get_uint16((const uint8_t *)p+1);
+}
+
+static uint32_t
+read_uint32(const char **ptr)
+{
+    const char *p = *ptr;
+    *ptr = (p + 4);
+    return get_uint32((const uint8_t *)p);
+}
+
+static uint64_t
+read_uint64(const char **ptr)
+{
+    const unsigned char *p = (const unsigned char *)*ptr;
+    *ptr = (char *)(p + 8);
+    return get_uint64(p);
+}
+
+static uintptr_t
+read_uintptr(const char **ptr)
+{
+    const unsigned char *p = (const unsigned char *)*ptr;
+    *ptr = (char *)(p + SIZEOF_VOIDP);
+#if SIZEOF_VOIDP == 8
+    return get_uint64(p);
+#else
+    return get_uint32(p);
+#endif
+}
+
+static uint64_t
+read_uint(DebugInfoReader *reader)
+{
+    if (reader->format == 4) {
+        return read_uint32(&reader->p);
+    } else { /* 64 bit */
+        return read_uint64(&reader->p);
+    }
+}
+
+static uint64_t
+read_uleb128(DebugInfoReader *reader)
+{
+    return uleb128(&reader->p);
+}
+
+static int64_t
+read_sleb128(DebugInfoReader *reader)
+{
+    return sleb128(&reader->p);
 }
 
-/* read file and fill lines */
 static void
-fill_lines(int num_traces, void **traces, char **syms, int check_debuglink,
-	   line_info_t *current_line, line_info_t *lines)
+debug_info_reader_init(DebugInfoReader *reader, obj_info_t *obj)
 {
-    int i;
+    reader->file = obj->mapped;
+    reader->obj = obj;
+    reader->p = obj->debug_info.ptr;
+    reader->pend = obj->debug_info.ptr + obj->debug_info.size;
+    reader->debug_line_cu_end = obj->debug_line.ptr;
+    reader->current_low_pc = 0;
+    reader->current_str_offsets_base = 0;
+    reader->current_addr_base = 0;
+    reader->current_rnglists_base = 0;
+}
+
+static void
+di_skip_die_attributes(const char **p)
+{
+    for (;;) {
+        uint64_t at = uleb128(p);
+        uint64_t form = uleb128(p);
+        if (!at && !form) break;
+        switch (form) {
+          default:
+            break;
+          case DW_FORM_implicit_const:
+            sleb128(p);
+            break;
+        }
+    }
+}
+
+static void
+di_read_debug_abbrev_cu(DebugInfoReader *reader)
+{
+    uint64_t prev = 0;
+    const char *p = reader->q0;
+    for (;;) {
+        uint64_t abbrev_number = uleb128(&p);
+        if (abbrev_number <= prev) break;
+        if (abbrev_number < ABBREV_TABLE_SIZE) {
+            reader->abbrev_table[abbrev_number] = p;
+        }
+        prev = abbrev_number;
+        uleb128(&p); /* tag */
+        p++; /* has_children */
+        di_skip_die_attributes(&p);
+    }
+}
+
+static int
+di_read_debug_line_cu(DebugInfoReader *reader)
+{
+    const char *p;
+    struct LineNumberProgramHeader header;
+
+    p = (const char *)reader->debug_line_cu_end;
+    if (parse_debug_line_header(reader->obj, &p, &header))
+        return -1;
+
+    reader->debug_line_cu_end = (char *)header.cu_end;
+    reader->debug_line_format = header.format;
+    reader->debug_line_version = header.version;
+    reader->debug_line_directories = (char *)header.include_directories;
+    reader->debug_line_files = (char *)header.filenames;
+
+    return 0;
+}
+
+static void
+set_addr_idx_value(DebugInfoValue *v, uint64_t n)
+{
+    v->as.addr_idx = n;
+    v->type = VAL_addr;
+}
+
+static void
+set_uint_value(DebugInfoValue *v, uint64_t n)
+{
+    v->as.uint64 = n;
+    v->type = VAL_uint;
+}
+
+static void
+set_int_value(DebugInfoValue *v, int64_t n)
+{
+    v->as.int64 = n;
+    v->type = VAL_int;
+}
+
+static void
+set_cstr_value(DebugInfoValue *v, const char *s)
+{
+    v->as.ptr = s;
+    v->off = 0;
+    v->type = VAL_cstr;
+}
+
+static void
+set_cstrp_value(DebugInfoValue *v, const char *s, uint64_t off)
+{
+    v->as.ptr = s;
+    v->off = off;
+    v->type = VAL_cstr;
+}
+
+static void
+set_data_value(DebugInfoValue *v, const char *s)
+{
+    v->as.ptr = s;
+    v->type = VAL_data;
+}
+
+static const char *
+get_cstr_value(DebugInfoValue *v)
+{
+    if (v->as.ptr) {
+        return v->as.ptr + v->off;
+    } else {
+        return NULL;
+    }
+}
+
+static const char *
+resolve_strx(DebugInfoReader *reader, uint64_t idx)
+{
+    const char *p = reader->obj->debug_str_offsets.ptr + reader->current_str_offsets_base;
+    uint64_t off;
+    if (reader->format == 4) {
+        off = ((uint32_t *)p)[idx];
+    }
+    else {
+        off = ((uint64_t *)p)[idx];
+    }
+    return reader->obj->debug_str.ptr + off;
+}
+
+static void
+debug_info_reader_read_addr_value(DebugInfoReader *reader, DebugInfoValue *v)
+{
+    if (reader->address_size == 4) {
+        set_uint_value(v, read_uint32(&reader->p));
+    } else if (reader->address_size == 8) {
+        set_uint_value(v, read_uint64(&reader->p));
+    } else {
+        fprintf(stderr,"unknown address_size:%d", reader->address_size);
+        abort();
+    }
+}
+
+static void
+debug_info_reader_read_value(DebugInfoReader *reader, uint64_t form, DebugInfoValue *v)
+{
+    switch (form) {
+      case DW_FORM_addr:
+        debug_info_reader_read_addr_value(reader, v);
+        break;
+      case DW_FORM_block2:
+        v->size = read_uint16(&reader->p);
+        set_data_value(v, reader->p);
+        reader->p += v->size;
+        break;
+      case DW_FORM_block4:
+        v->size = read_uint32(&reader->p);
+        set_data_value(v, reader->p);
+        reader->p += v->size;
+        break;
+      case DW_FORM_data2:
+        set_uint_value(v, read_uint16(&reader->p));
+        break;
+      case DW_FORM_data4:
+        set_uint_value(v, read_uint32(&reader->p));
+        break;
+      case DW_FORM_data8:
+        set_uint_value(v, read_uint64(&reader->p));
+        break;
+      case DW_FORM_string:
+        v->size = strlen(reader->p);
+        set_cstr_value(v, reader->p);
+        reader->p += v->size + 1;
+        break;
+      case DW_FORM_block:
+        v->size = uleb128(&reader->p);
+        set_data_value(v, reader->p);
+        reader->p += v->size;
+        break;
+      case DW_FORM_block1:
+        v->size = read_uint8(&reader->p);
+        set_data_value(v, reader->p);
+        reader->p += v->size;
+        break;
+      case DW_FORM_data1:
+        set_uint_value(v, read_uint8(&reader->p));
+        break;
+      case DW_FORM_flag:
+        set_uint_value(v, read_uint8(&reader->p));
+        break;
+      case DW_FORM_sdata:
+        set_int_value(v, read_sleb128(reader));
+        break;
+      case DW_FORM_strp:
+        set_cstrp_value(v, reader->obj->debug_str.ptr, read_uint(reader));
+        break;
+      case DW_FORM_udata:
+        set_uint_value(v, read_uleb128(reader));
+        break;
+      case DW_FORM_ref_addr:
+        if (reader->current_version <= 2) {
+            // DWARF Version 2 specifies that references have
+            // the same size as an address on the target system
+            debug_info_reader_read_addr_value(reader, v);
+        } else {
+            if (reader->format == 4) {
+                set_uint_value(v, read_uint32(&reader->p));
+            } else if (reader->format == 8) {
+                set_uint_value(v, read_uint64(&reader->p));
+            } else {
+                fprintf(stderr,"unknown format:%d", reader->format);
+                abort();
+            }
+        }
+        break;
+      case DW_FORM_ref1:
+        set_uint_value(v, read_uint8(&reader->p));
+        break;
+      case DW_FORM_ref2:
+        set_uint_value(v, read_uint16(&reader->p));
+        break;
+      case DW_FORM_ref4:
+        set_uint_value(v, read_uint32(&reader->p));
+        break;
+      case DW_FORM_ref8:
+        set_uint_value(v, read_uint64(&reader->p));
+        break;
+      case DW_FORM_ref_udata:
+        set_uint_value(v, uleb128(&reader->p));
+        break;
+      case DW_FORM_indirect:
+        /* TODO: read the referred value */
+        set_uint_value(v, uleb128(&reader->p));
+        break;
+      case DW_FORM_sec_offset:
+        set_uint_value(v, read_uint(reader)); /* offset */
+        /* addrptr: debug_addr */
+        /* lineptr: debug_line */
+        /* loclist: debug_loclists */
+        /* loclistptr: debug_loclists */
+        /* macptr: debug_macro */
+        /* rnglist: debug_rnglists */
+        /* rnglistptr: debug_rnglists */
+        /* stroffsetsptr: debug_str_offsets */
+        break;
+      case DW_FORM_exprloc:
+        v->size = (size_t)read_uleb128(reader);
+        set_data_value(v, reader->p);
+        reader->p += v->size;
+        break;
+      case DW_FORM_flag_present:
+        set_uint_value(v, 1);
+        break;
+      case DW_FORM_strx:
+        set_cstr_value(v, resolve_strx(reader, uleb128(&reader->p)));
+        break;
+      case DW_FORM_addrx:
+        set_addr_idx_value(v, uleb128(&reader->p));
+        break;
+      case DW_FORM_ref_sup4:
+        set_uint_value(v, read_uint32(&reader->p));
+        break;
+      case DW_FORM_strp_sup:
+        set_uint_value(v, read_uint(reader));
+        /* *p = reader->sup_file + reader->sup_str->sh_offset + ret; */
+        break;
+      case DW_FORM_data16:
+        v->size = 16;
+        set_data_value(v, reader->p);
+        reader->p += v->size;
+        break;
+      case DW_FORM_line_strp:
+        set_cstrp_value(v, reader->obj->debug_line_str.ptr, read_uint(reader));
+        break;
+      case DW_FORM_ref_sig8:
+        set_uint_value(v, read_uint64(&reader->p));
+        break;
+      case DW_FORM_implicit_const:
+        set_int_value(v, sleb128(&reader->q));
+        break;
+      case DW_FORM_loclistx:
+        set_uint_value(v, read_uleb128(reader));
+        break;
+      case DW_FORM_rnglistx:
+        set_uint_value(v, read_uleb128(reader));
+        break;
+      case DW_FORM_ref_sup8:
+        set_uint_value(v, read_uint64(&reader->p));
+        break;
+      case DW_FORM_strx1:
+        set_cstr_value(v, resolve_strx(reader, read_uint8(&reader->p)));
+        break;
+      case DW_FORM_strx2:
+        set_cstr_value(v, resolve_strx(reader, read_uint16(&reader->p)));
+        break;
+      case DW_FORM_strx3:
+        set_cstr_value(v, resolve_strx(reader, read_uint24(&reader->p)));
+        break;
+      case DW_FORM_strx4:
+        set_cstr_value(v, resolve_strx(reader, read_uint32(&reader->p)));
+        break;
+      case DW_FORM_addrx1:
+        set_addr_idx_value(v, read_uint8(&reader->p));
+        break;
+      case DW_FORM_addrx2:
+        set_addr_idx_value(v, read_uint16(&reader->p));
+        break;
+      case DW_FORM_addrx3:
+        set_addr_idx_value(v, read_uint24(&reader->p));
+        break;
+      case DW_FORM_addrx4:
+        set_addr_idx_value(v, read_uint32(&reader->p));
+        break;
+      case 0:
+        goto fail;
+        break;
+    }
+    return;
+
+  fail:
+    fprintf(stderr, "%d: unsupported form: %#"PRIx64"\n", __LINE__, form);
+    exit(1);
+}
+
+/* find abbrev in current compilation unit */
+static const char *
+di_find_abbrev(DebugInfoReader *reader, uint64_t abbrev_number)
+{
+    const char *p;
+    if (abbrev_number < ABBREV_TABLE_SIZE) {
+        return reader->abbrev_table[abbrev_number];
+    }
+    p = reader->abbrev_table[ABBREV_TABLE_SIZE-1];
+    /* skip 255th record */
+    uleb128(&p); /* tag */
+    p++; /* has_children */
+    di_skip_die_attributes(&p);
+    for (uint64_t n = uleb128(&p); abbrev_number != n; n = uleb128(&p)) {
+        if (n == 0) {
+            fprintf(stderr,"%d: Abbrev Number %"PRId64" not found\n",__LINE__, abbrev_number);
+            exit(1);
+        }
+        uleb128(&p); /* tag */
+        p++; /* has_children */
+        di_skip_die_attributes(&p);
+    }
+    return p;
+}
+
+#if 0
+static void
+hexdump0(const unsigned char *p, size_t n)
+{
+    size_t i;
+    fprintf(stderr, "     0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F\n");
+    for (i=0; i < n; i++){
+        switch (i & 15) {
+          case 0:
+            fprintf(stderr, "%02" PRIdSIZE ": %02X ", i/16, p[i]);
+            break;
+          case 15:
+            fprintf(stderr, "%02X\n", p[i]);
+            break;
+          default:
+            fprintf(stderr, "%02X ", p[i]);
+            break;
+        }
+    }
+    if ((i & 15) != 15) {
+        fprintf(stderr, "\n");
+    }
+}
+#define hexdump(p,n) hexdump0((const unsigned char *)p, n)
+
+static void
+div_inspect(DebugInfoValue *v)
+{
+    switch (v->type) {
+      case VAL_uint:
+        fprintf(stderr,"%d: type:%d size:%" PRIxSIZE " v:%"PRIx64"\n",__LINE__,v->type,v->size,v->as.uint64);
+        break;
+      case VAL_int:
+        fprintf(stderr,"%d: type:%d size:%" PRIxSIZE " v:%"PRId64"\n",__LINE__,v->type,v->size,(int64_t)v->as.uint64);
+        break;
+      case VAL_cstr:
+        fprintf(stderr,"%d: type:%d size:%" PRIxSIZE " v:'%s'\n",__LINE__,v->type,v->size,v->as.ptr);
+        break;
+      case VAL_data:
+        fprintf(stderr,"%d: type:%d size:%" PRIxSIZE " v:\n",__LINE__,v->type,v->size);
+        hexdump(v->as.ptr, 16);
+        break;
+    }
+}
+#endif
+
+static DIE *
+di_read_die(DebugInfoReader *reader, DIE *die)
+{
+    uint64_t abbrev_number = uleb128(&reader->p);
+    if (abbrev_number == 0) {
+        reader->level--;
+        return NULL;
+    }
+
+    reader->q = di_find_abbrev(reader, abbrev_number);
+
+    die->pos = reader->p - reader->obj->debug_info.ptr - 1;
+    die->tag = (int)uleb128(&reader->q); /* tag */
+    die->has_children = *reader->q++; /* has_children */
+    if (die->has_children) {
+        reader->level++;
+    }
+    return die;
+}
+
+static DebugInfoValue *
+di_read_record(DebugInfoReader *reader, DebugInfoValue *vp)
+{
+    uint64_t at = uleb128(&reader->q);
+    uint64_t form = uleb128(&reader->q);
+    if (!at || !form) return NULL;
+    vp->at = at;
+    vp->form = form;
+    debug_info_reader_read_value(reader, form, vp);
+    return vp;
+}
+
+static void
+di_skip_records(DebugInfoReader *reader)
+{
+    for (;;) {
+        DebugInfoValue v = {{}};
+        uint64_t at = uleb128(&reader->q);
+        uint64_t form = uleb128(&reader->q);
+        if (!at || !form) return;
+        debug_info_reader_read_value(reader, form, &v);
+    }
+}
+
+typedef struct addr_header {
+    const char *ptr;
+    uint64_t unit_length;
+    uint8_t format;
+    uint8_t address_size;
+    /* uint8_t segment_selector_size; */
+} addr_header_t;
+
+static void
+addr_header_init(obj_info_t *obj, addr_header_t *header) {
+    const char *p = obj->debug_addr.ptr;
+
+    header->ptr = p;
+
+    if (!p) return;
+
+    header->unit_length = *(uint32_t *)p;
+    p += sizeof(uint32_t);
+
+    header->format = 4;
+    if (header->unit_length == 0xffffffff) {
+        header->unit_length = *(uint64_t *)p;
+        p += sizeof(uint64_t);
+        header->format = 8;
+    }
+
+    p += 2; /* version */
+    header->address_size = *p++;
+    p++; /* segment_selector_size */
+}
+
+static uint64_t
+read_addr(addr_header_t *header, uint64_t addr_base, uint64_t idx) {
+    if (header->address_size == 4) {
+        return ((uint32_t*)(header->ptr + addr_base))[idx];
+    }
+    else {
+        return ((uint64_t*)(header->ptr + addr_base))[idx];
+    }
+}
+
+typedef struct rnglists_header {
+    uint64_t unit_length;
+    uint8_t format;
+    uint8_t address_size;
+    uint32_t offset_entry_count;
+} rnglists_header_t;
+
+static void
+rnglists_header_init(obj_info_t *obj, rnglists_header_t *header) {
+    const char *p = obj->debug_rnglists.ptr;
+
+    if (!p) return;
+
+    header->unit_length = *(uint32_t *)p;
+    p += sizeof(uint32_t);
+
+    header->format = 4;
+    if (header->unit_length == 0xffffffff) {
+        header->unit_length = *(uint64_t *)p;
+        p += sizeof(uint64_t);
+        header->format = 8;
+    }
+
+    p += 2; /* version */
+    header->address_size = *p++;
+    p++; /* segment_selector_size */
+    header->offset_entry_count = *(uint32_t *)p;
+}
+
+typedef struct {
+    uint64_t low_pc;
+    uint64_t high_pc;
+    uint64_t ranges;
+    bool low_pc_set;
+    bool high_pc_set;
+    bool ranges_set;
+} ranges_t;
+
+static void
+ranges_set(ranges_t *ptr, DebugInfoValue *v, addr_header_t *addr_header, uint64_t addr_base)
+{
+    uint64_t n = 0;
+    if (v->type == VAL_uint) {
+        n = v->as.uint64;
+    }
+    else if (v->type == VAL_addr) {
+        n = read_addr(addr_header, addr_base, v->as.addr_idx);
+    }
+    switch (v->at) {
+      case DW_AT_low_pc:
+        ptr->low_pc = n;
+        ptr->low_pc_set = true;
+        break;
+      case DW_AT_high_pc:
+        if (v->form == DW_FORM_addr) {
+            ptr->high_pc = n;
+        }
+        else {
+            ptr->high_pc = ptr->low_pc + n;
+        }
+        ptr->high_pc_set = true;
+        break;
+      case DW_AT_ranges:
+        ptr->ranges = n;
+        ptr->ranges_set = true;
+        break;
+    }
+}
+
+static uint64_t
+read_dw_form_addr(DebugInfoReader *reader, const char **ptr)
+{
+    const char *p = *ptr;
+    *ptr = p + reader->address_size;
+    if (reader->address_size == 4) {
+        return read_uint32(&p);
+    } else if (reader->address_size == 8) {
+        return read_uint64(&p);
+    } else {
+        fprintf(stderr,"unknown address_size:%d", reader->address_size);
+        abort();
+    }
+}
+
+static uintptr_t
+ranges_include(DebugInfoReader *reader, ranges_t *ptr, uint64_t addr, rnglists_header_t *rnglists_header)
+{
+    if (ptr->high_pc_set) {
+        if (ptr->ranges_set || !ptr->low_pc_set) {
+            exit(1);
+        }
+        if (ptr->low_pc <= addr && addr <= ptr->high_pc) {
+            return (uintptr_t)ptr->low_pc;
+        }
+    }
+    else if (ptr->ranges_set) {
+        /* TODO: support base address selection entry */
+        const char *p;
+        uint64_t base = ptr->low_pc_set ? ptr->low_pc : reader->current_low_pc;
+        bool base_valid = true;
+        if (reader->current_version >= 5) {
+            if (rnglists_header->offset_entry_count == 0) {
+                // DW_FORM_sec_offset
+                p = reader->obj->debug_rnglists.ptr + ptr->ranges + reader->current_rnglists_base;
+            }
+            else {
+                // DW_FORM_rnglistx
+                const char *offset_array = reader->obj->debug_rnglists.ptr + reader->current_rnglists_base;
+                if (rnglists_header->format == 4) {
+                    p = offset_array + ((uint32_t *)offset_array)[ptr->ranges];
+                }
+                else {
+                    p = offset_array + ((uint64_t *)offset_array)[ptr->ranges];
+                }
+            }
+            for (;;) {
+                uint8_t rle = read_uint8(&p);
+                uintptr_t from = 0, to = 0;
+                if (rle == DW_RLE_end_of_list) break;
+                switch (rle) {
+                  case DW_RLE_base_addressx:
+                    uleb128(&p);
+                    base_valid = false; /* not supported yet */
+                    break;
+                  case DW_RLE_startx_endx:
+                    uleb128(&p);
+                    uleb128(&p);
+                    break;
+                  case DW_RLE_startx_length:
+                    uleb128(&p);
+                    uleb128(&p);
+                    break;
+                  case DW_RLE_offset_pair:
+                    if (!base_valid) break;
+                    from = (uintptr_t)base + uleb128(&p);
+                    to = (uintptr_t)base + uleb128(&p);
+                    break;
+                  case DW_RLE_base_address:
+                    base = read_dw_form_addr(reader, &p);
+                    base_valid = true;
+                    break;
+                  case DW_RLE_start_end:
+                    from = (uintptr_t)read_dw_form_addr(reader, &p);
+                    to = (uintptr_t)read_dw_form_addr(reader, &p);
+                    break;
+                  case DW_RLE_start_length:
+                    from = (uintptr_t)read_dw_form_addr(reader, &p);
+                    to = from + uleb128(&p);
+                    break;
+                }
+                if (from <= addr && addr < to) {
+                    return from;
+                }
+            }
+            return false;
+        }
+        p = reader->obj->debug_ranges.ptr + ptr->ranges;
+        for (;;) {
+            uintptr_t from = read_uintptr(&p);
+            uintptr_t to = read_uintptr(&p);
+            if (!from && !to) break;
+            if (from == UINTPTR_MAX) {
+                /* base address selection entry */
+                base = to;
+            }
+            else if (base + from <= addr && addr < base + to) {
+                return (uintptr_t)base + from;
+            }
+        }
+    }
+    else if (ptr->low_pc_set) {
+        if (ptr->low_pc == addr) {
+            return (uintptr_t)ptr->low_pc;
+        }
+    }
+    return false;
+}
+
+#if 0
+static void
+ranges_inspect(DebugInfoReader *reader, ranges_t *ptr)
+{
+    if (ptr->high_pc_set) {
+        if (ptr->ranges_set || !ptr->low_pc_set) {
+            fprintf(stderr,"low_pc_set:%d high_pc_set:%d ranges_set:%d\n",ptr->low_pc_set,ptr->high_pc_set,ptr->ranges_set);
+            exit(1);
+        }
+        fprintf(stderr,"low_pc:%"PRIx64" high_pc:%"PRIx64"\n",ptr->low_pc,ptr->high_pc);
+    }
+    else if (ptr->ranges_set) {
+        char *p = reader->obj->debug_ranges.ptr + ptr->ranges;
+        fprintf(stderr,"low_pc:%"PRIx64" ranges:%"PRIx64" %lx ",ptr->low_pc,ptr->ranges, p-reader->obj->mapped);
+        for (;;) {
+            uintptr_t from = read_uintptr(&p);
+            uintptr_t to = read_uintptr(&p);
+            if (!from && !to) break;
+            fprintf(stderr,"%"PRIx64"-%"PRIx64" ",ptr->low_pc+from,ptr->low_pc+to);
+        }
+        fprintf(stderr,"\n");
+    }
+    else if (ptr->low_pc_set) {
+        fprintf(stderr,"low_pc:%"PRIx64"\n",ptr->low_pc);
+    }
+    else {
+        fprintf(stderr,"empty\n");
+    }
+}
+#endif
+
+static int
+di_read_cu(DebugInfoReader *reader)
+{
+    uint64_t unit_length;
+    uint16_t version;
+    uint64_t debug_abbrev_offset;
+    reader->format = 4;
+    reader->current_cu = reader->p;
+    unit_length = read_uint32(&reader->p);
+    if (unit_length == 0xffffffff) {
+        unit_length = read_uint64(&reader->p);
+        reader->format = 8;
+    }
+    reader->cu_end = reader->p + unit_length;
+    version = read_uint16(&reader->p);
+    reader->current_version = version;
+    if (version > 5) {
+        return -1;
+    }
+    else if (version == 5) {
+        /* unit_type = */ read_uint8(&reader->p);
+        reader->address_size = read_uint8(&reader->p);
+        debug_abbrev_offset = read_uint(reader);
+    }
+    else {
+        debug_abbrev_offset = read_uint(reader);
+        reader->address_size = read_uint8(&reader->p);
+    }
+    reader->q0 = reader->obj->debug_abbrev.ptr + debug_abbrev_offset;
+
+    reader->level = 0;
+    di_read_debug_abbrev_cu(reader);
+    if (di_read_debug_line_cu(reader)) return -1;
+
+#if defined(__GNUC__) && !defined(__clang__) && !defined(__INTEL_COMPILER_BUILD_DATE)
+    /* Though DWARF specifies "the applicable base address defaults to the base
+       address of the compilation unit", but GCC seems to use zero as default */
+#else
+    do {
+        DIE die;
+
+        if (!di_read_die(reader, &die)) continue;
+
+        if (die.tag != DW_TAG_compile_unit) {
+            di_skip_records(reader);
+            break;
+        }
+
+        reader->current_str_offsets_base = 0;
+        reader->current_addr_base = 0;
+        reader->current_rnglists_base = 0;
+
+        DebugInfoValue low_pc = {{}};
+        /* enumerate abbrev */
+        for (;;) {
+            DebugInfoValue v = {{}};
+            if (!di_read_record(reader, &v)) break;
+            switch (v.at) {
+              case DW_AT_low_pc:
+                // clang may output DW_AT_addr_base after DW_AT_low_pc.
+                // We need to resolve the DW_FORM_addr* after DW_AT_addr_base is parsed.
+                low_pc = v;
+                break;
+              case DW_AT_str_offsets_base:
+                reader->current_str_offsets_base = v.as.uint64;
+                break;
+              case DW_AT_addr_base:
+                reader->current_addr_base = v.as.uint64;
+                break;
+              case DW_AT_rnglists_base:
+                reader->current_rnglists_base = v.as.uint64;
+                break;
+            }
+        }
+        // Resolve the DW_FORM_addr of DW_AT_low_pc
+        switch (low_pc.type) {
+            case VAL_uint:
+                reader->current_low_pc = low_pc.as.uint64;
+                break;
+            case VAL_addr:
+                {
+                    addr_header_t header;
+                    addr_header_init(reader->obj, &header);
+                    reader->current_low_pc = read_addr(&header, reader->current_addr_base, low_pc.as.addr_idx);
+                }
+                break;
+        }
+    } while (0);
+#endif
+    return 0;
+}
+
+static void
+read_abstract_origin(DebugInfoReader *reader, uint64_t form, uint64_t abstract_origin, line_info_t *line)
+{
+    const char *p = reader->p;
+    const char *q = reader->q;
+    int level = reader->level;
+    DIE die;
+
+    switch (form) {
+      case DW_FORM_ref1:
+      case DW_FORM_ref2:
+      case DW_FORM_ref4:
+      case DW_FORM_ref8:
+      case DW_FORM_ref_udata:
+        reader->p = reader->current_cu + abstract_origin;
+        break;
+      case DW_FORM_ref_addr:
+        goto finish; /* not supported yet */
+      case DW_FORM_ref_sig8:
+        goto finish; /* not supported yet */
+      case DW_FORM_ref_sup4:
+      case DW_FORM_ref_sup8:
+        goto finish; /* not supported yet */
+      default:
+        goto finish;
+    }
+    if (!di_read_die(reader, &die)) goto finish;
+
+    /* enumerate abbrev */
+    for (;;) {
+        DebugInfoValue v = {{}};
+        if (!di_read_record(reader, &v)) break;
+        switch (v.at) {
+          case DW_AT_name:
+            line->sname = get_cstr_value(&v);
+            break;
+        }
+    }
+
+  finish:
+    reader->p = p;
+    reader->q = q;
+    reader->level = level;
+}
+
+static void
+debug_info_read(DebugInfoReader *reader, int num_traces, void **traces,
+         line_info_t *lines, int offset) {
+
+    addr_header_t addr_header = {};
+    addr_header_init(reader->obj, &addr_header);
+
+    rnglists_header_t rnglists_header = {};
+    rnglists_header_init(reader->obj, &rnglists_header);
+
+    while (reader->p < reader->cu_end) {
+        DIE die;
+        ranges_t ranges = {};
+        line_info_t line = {};
+
+        if (!di_read_die(reader, &die)) continue;
+        /* fprintf(stderr,"%d:%tx: <%d>\n",__LINE__,die.pos,reader->level,die.tag); */
+
+        if (die.tag != DW_TAG_subprogram && die.tag != DW_TAG_inlined_subroutine) {
+          skip_die:
+            di_skip_records(reader);
+            continue;
+        }
+
+        /* enumerate abbrev */
+        for (;;) {
+            DebugInfoValue v = {{}};
+            /* ptrdiff_t pos = reader->p - reader->p0; */
+            if (!di_read_record(reader, &v)) break;
+            /* fprintf(stderr,"\n%d:%tx: AT:%lx FORM:%lx\n",__LINE__,pos,v.at,v.form); */
+            /* div_inspect(&v); */
+            switch (v.at) {
+              case DW_AT_name:
+                line.sname = get_cstr_value(&v);
+                break;
+              case DW_AT_call_file:
+                fill_filename((int)v.as.uint64, reader->debug_line_format, reader->debug_line_version, reader->debug_line_directories, reader->debug_line_files, &line, reader->obj);
+                break;
+              case DW_AT_call_line:
+                line.line = (int)v.as.uint64;
+                break;
+              case DW_AT_low_pc:
+              case DW_AT_high_pc:
+              case DW_AT_ranges:
+                ranges_set(&ranges, &v, &addr_header, reader->current_addr_base);
+                break;
+              case DW_AT_declaration:
+                goto skip_die;
+              case DW_AT_inline:
+                /* 1 or 3 */
+                break; /* goto skip_die; */
+              case DW_AT_abstract_origin:
+                read_abstract_origin(reader, v.form, v.as.uint64, &line);
+                break; /* goto skip_die; */
+            }
+        }
+        /* ranges_inspect(reader, &ranges); */
+        /* fprintf(stderr,"%d:%tx: %x ",__LINE__,diepos,die.tag); */
+        for (int i=offset; i < num_traces; i++) {
+            uintptr_t addr = (uintptr_t)traces[i];
+            uintptr_t offset = addr - reader->obj->base_addr + reader->obj->vmaddr;
+            uintptr_t saddr = ranges_include(reader, &ranges, offset, &rnglists_header);
+            if (saddr) {
+                /* fprintf(stdout, "%d:%tx: %d %lx->%lx %x %s: %s/%s %d %s %s %s\n",__LINE__,die.pos, i,addr,offset, die.tag,line.sname,line.dirname,line.filename,line.line,reader->obj->path,line.sname,lines[i].sname); */
+                if (lines[i].sname) {
+                    line_info_t *lp = malloc(sizeof(line_info_t));
+                    memcpy(lp, &lines[i], sizeof(line_info_t));
+                    lines[i].next = lp;
+                    lp->dirname = line.dirname;
+                    lp->filename = line.filename;
+                    lp->line = line.line;
+                    lp->saddr = 0;
+                }
+                lines[i].path = reader->obj->path;
+                lines[i].base_addr = line.base_addr;
+                lines[i].sname = line.sname;
+                lines[i].saddr = saddr + reader->obj->base_addr - reader->obj->vmaddr;
+            }
+        }
+    }
+}
+
+// This function parses the following attributes of Line Number Program Header in DWARF 5:
+//
+// * directory_entry_format_count
+// * directory_entry_format
+// * directories_count
+// * directories
+//
+// or
+//
+// * file_name_entry_format_count
+// * file_name_entry_format
+// * file_names_count
+// * file_names
+//
+// It records DW_LNCT_path and DW_LNCT_directory_index at the index "idx".
+static const char *
+parse_ver5_debug_line_header(const char *p, int idx, uint8_t format, obj_info_t *obj, const char **out_path, uint64_t *out_directory_index) {
+    int i, j;
+    int entry_format_count = *(uint8_t *)p++;
+    const char *entry_format = p;
+
+    /* skip the part of entry_format */
+    for (i = 0; i < entry_format_count * 2; i++) uleb128(&p);
+
+    int entry_count = (int)uleb128(&p);
+
+    DebugInfoReader reader;
+    debug_info_reader_init(&reader, obj);
+    reader.format = format;
+    reader.p = p;
+    for (j = 0; j < entry_count; j++) {
+        const char *format = entry_format;
+        for (i = 0; i < entry_format_count; i++) {
+            DebugInfoValue v = {{}};
+            unsigned long dw_lnct = uleb128(&format);
+            unsigned long dw_form = uleb128(&format);
+            debug_info_reader_read_value(&reader, dw_form, &v);
+            if (dw_lnct == 1 /* DW_LNCT_path */ && v.type == VAL_cstr && out_path)
+                *out_path = v.as.ptr + v.off;
+            if (dw_lnct == 2 /* DW_LNCT_directory_index */ && v.type == VAL_uint && out_directory_index)
+                *out_directory_index = v.as.uint64;
+        }
+        if (j == idx) return 0;
+    }
+
+    return reader.p;
+}
+
+#ifdef USE_ELF
+static unsigned long
+uncompress_debug_section(ElfW(Shdr) *shdr, char *file, char **ptr)
+{
+    *ptr = NULL;
+#ifdef SUPPORT_COMPRESSED_DEBUG_LINE
+    ElfW(Chdr) *chdr = (ElfW(Chdr) *)(file + shdr->sh_offset);
+    unsigned long destsize = chdr->ch_size;
+    int ret = 0;
+
+    if (chdr->ch_type != ELFCOMPRESS_ZLIB) {
+	/* unsupported compression type */
+	return 0;
+    }
+
+    *ptr = malloc(destsize);
+    if (!*ptr) return 0;
+    ret = uncompress((Bytef *)*ptr, &destsize,
+	    (const Bytef*)chdr + sizeof(ElfW(Chdr)),
+            shdr->sh_size - sizeof(ElfW(Chdr)));
+    if (ret != Z_OK) goto fail;
+    return destsize;
+
+fail:
+    free(*ptr);
+    *ptr = NULL;
+#endif
+    return 0;
+}
+
+/* read file and fill lines */
+static uintptr_t
+fill_lines(int num_traces, void **traces, int check_debuglink,
+	   obj_info_t **objp, line_info_t *lines, int offset)
+{
+    int i, j;
     char *shstr;
-    char *section_name;
     ElfW(Ehdr) *ehdr;
     ElfW(Shdr) *shdr, *shstr_shdr;
-    ElfW(Shdr) *debug_line_shdr = NULL, *gnu_debuglink_shdr = NULL;
+    ElfW(Shdr) *gnu_debuglink_shdr = NULL;
+    ElfW(Shdr) *note_gnu_build_id = NULL;
     int fd;
     off_t filesize;
     char *file;
+    ElfW(Shdr) *symtab_shdr = NULL, *strtab_shdr = NULL;
+    ElfW(Shdr) *dynsym_shdr = NULL, *dynstr_shdr = NULL;
+    obj_info_t *obj = *objp;
+    uintptr_t dladdr_fbase = 0;
 
     fd = open(binary_filename, O_RDONLY);
     if (fd < 0) {
-	return;
+	goto fail;
     }
     filesize = lseek(fd, 0, SEEK_END);
     if (filesize < 0) {
 	int e = errno;
 	close(fd);
 	kprintf("lseek: %s\n", strerror(e));
-	return;
+	goto fail;
     }
 #if SIZEOF_OFF_T > SIZEOF_SIZE_T
     if (filesize > (off_t)SIZE_MAX) {
 	close(fd);
 	kprintf("Too large file %s\n", binary_filename);
-	return;
+	goto fail;
     }
 #endif
     lseek(fd, 0, SEEK_SET);
@@ -494,8 +2044,9 @@ fill_lines(int num_traces, void **traces, char **syms, int check_debuglink,
 	int e = errno;
 	close(fd);
 	kprintf("mmap: %s\n", strerror(e));
-	return;
+	goto fail;
     }
+    close(fd);
 
     ehdr = (ElfW(Ehdr) *)file;
     if (memcmp(ehdr->e_ident, "\177ELF", 4) != 0) {
@@ -503,22 +2054,10 @@ fill_lines(int num_traces, void **traces, char **syms, int check_debuglink,
 	 * Huh? Maybe filename was overridden by setproctitle() and
 	 * it match non-elf file.
 	 */
-	close(fd);
-	return;
-    }
-
-    current_line->fd = fd;
-    current_line->mapped = file;
-    current_line->mapped_size = (size_t)filesize;
-
-    for (i = 0; i < num_traces; i++) {
-	const char *path;
-	size_t len;
-	if (get_path_from_symbol(syms[i], &path, &len) &&
-		!strncmp(path, binary_filename, len)) {
-	    lines[i].line = -1;
-	}
+	goto fail;
     }
+    obj->mapped = file;
+    obj->mapped_size = (size_t)filesize;
 
     shdr = (ElfW(Shdr) *)(file + ehdr->e_shoff);
 
@@ -526,125 +2065,590 @@ fill_lines(int num_traces, void **traces, char **syms, int check_debuglink,
     shstr = file + shstr_shdr->sh_offset;
 
     for (i = 0; i < ehdr->e_shnum; i++) {
-	section_name = shstr + shdr[i].sh_name;
-	if (!strcmp(section_name, ".debug_line")) {
-	    debug_line_shdr = shdr + i;
+        char *section_name = shstr + shdr[i].sh_name;
+	switch (shdr[i].sh_type) {
+	  case SHT_STRTAB:
+	    if (!strcmp(section_name, ".strtab")) {
+		strtab_shdr = shdr + i;
+	    }
+	    else if (!strcmp(section_name, ".dynstr")) {
+		dynstr_shdr = shdr + i;
+	    }
+	    break;
+	  case SHT_SYMTAB:
+	    /* if (!strcmp(section_name, ".symtab")) */
+	    symtab_shdr = shdr + i;
 	    break;
-	} else if (!strcmp(section_name, ".gnu_debuglink")) {
-	    gnu_debuglink_shdr = shdr + i;
+	  case SHT_DYNSYM:
+	    /* if (!strcmp(section_name, ".dynsym")) */
+	    dynsym_shdr = shdr + i;
+	    break;
+          case SHT_NOTE:
+            if (!strcmp(section_name, ".note.gnu.build-id")) {
+                note_gnu_build_id = shdr + i;
+            }
+            break;
+	  case SHT_PROGBITS:
+	    if (!strcmp(section_name, ".gnu_debuglink")) {
+		gnu_debuglink_shdr = shdr + i;
+	    }
+            else {
+                const char *debug_section_names[] = {
+                    ".debug_abbrev",
+                    ".debug_info",
+                    ".debug_line",
+                    ".debug_ranges",
+                    ".debug_str_offsets",
+                    ".debug_addr",
+                    ".debug_rnglists",
+                    ".debug_str",
+                    ".debug_line_str"
+                };
+
+                for (j=0; j < DWARF_SECTION_COUNT; j++) {
+                    struct dwarf_section *s = obj_dwarf_section_at(obj, j);
+
+                    if (strcmp(section_name, debug_section_names[j]) != 0)
+                        continue;
+
+                    s->ptr = file + shdr[i].sh_offset;
+                    s->size = shdr[i].sh_size;
+                    s->flags = shdr[i].sh_flags;
+                    if (s->flags & SHF_COMPRESSED) {
+                        s->size = uncompress_debug_section(&shdr[i], file, &s->ptr);
+                        if (!s->size) goto fail;
+                    }
+                    break;
+                }
+            }
+	    break;
+	}
+    }
+
+    if (offset == -1) {
+	/* main executable */
+	offset = 0;
+	if (dynsym_shdr && dynstr_shdr) {
+	    char *strtab = file + dynstr_shdr->sh_offset;
+	    ElfW(Sym) *symtab = (ElfW(Sym) *)(file + dynsym_shdr->sh_offset);
+	    int symtab_count = (int)(dynsym_shdr->sh_size / sizeof(ElfW(Sym)));
+            void *handle = dlopen(NULL, RTLD_NOW|RTLD_LOCAL);
+            if (handle) {
+                for (j = 0; j < symtab_count; j++) {
+                    ElfW(Sym) *sym = &symtab[j];
+                    Dl_info info;
+                    void *s;
+                    if (ELF_ST_TYPE(sym->st_info) != STT_FUNC || sym->st_size == 0) continue;
+                    s = dlsym(handle, strtab + sym->st_name);
+                    if (s && dladdr(s, &info)) {
+                        obj->base_addr = dladdr_fbase;
+                        dladdr_fbase = (uintptr_t)info.dli_fbase;
+                        break;
+                    }
+                }
+                dlclose(handle);
+            }
+	    if (ehdr->e_type == ET_EXEC) {
+		obj->base_addr = 0;
+	    }
+	    else {
+		/* PIE (position-independent executable) */
+		obj->base_addr = dladdr_fbase;
+	    }
 	}
     }
 
-    if (!debug_line_shdr) {
+    if (obj->debug_info.ptr && obj->debug_abbrev.ptr) {
+        DebugInfoReader reader;
+        debug_info_reader_init(&reader, obj);
+        i = 0;
+        while (reader.p < reader.pend) {
+            /* fprintf(stderr, "%d:%tx: CU[%d]\n", __LINE__, reader.p - reader.obj->debug_info.ptr, i++); */
+            if (di_read_cu(&reader)) goto use_symtab;
+            debug_info_read(&reader, num_traces, traces, lines, offset);
+        }
+    }
+    else {
+        /* This file doesn't have dwarf, use symtab or dynsym */
+use_symtab:
+        if (!symtab_shdr) {
+            /* This file doesn't have symtab, use dynsym instead */
+            symtab_shdr = dynsym_shdr;
+            strtab_shdr = dynstr_shdr;
+        }
+
+        if (symtab_shdr && strtab_shdr) {
+            char *strtab = file + strtab_shdr->sh_offset;
+            ElfW(Sym) *symtab = (ElfW(Sym) *)(file + symtab_shdr->sh_offset);
+            int symtab_count = (int)(symtab_shdr->sh_size / sizeof(ElfW(Sym)));
+            for (j = 0; j < symtab_count; j++) {
+                ElfW(Sym) *sym = &symtab[j];
+                uintptr_t saddr = (uintptr_t)sym->st_value + obj->base_addr;
+                if (ELF_ST_TYPE(sym->st_info) != STT_FUNC) continue;
+                for (i = offset; i < num_traces; i++) {
+                    uintptr_t d = (uintptr_t)traces[i] - saddr;
+                    if (lines[i].line > 0 || d > (uintptr_t)sym->st_size)
+                        continue;
+                    /* fill symbol name and addr from .symtab */
+                    if (!lines[i].sname) lines[i].sname = strtab + sym->st_name;
+                    lines[i].saddr = saddr;
+                    lines[i].path  = obj->path;
+                    lines[i].base_addr = obj->base_addr;
+                }
+            }
+        }
+    }
+
+    if (!obj->debug_line.ptr) {
 	/* This file doesn't have .debug_line section,
 	   let's check .gnu_debuglink section instead. */
 	if (gnu_debuglink_shdr && check_debuglink) {
 	    follow_debuglink(file + gnu_debuglink_shdr->sh_offset,
-			     num_traces, traces, syms,
-			     current_line, lines);
+			     num_traces, traces,
+			     objp, lines, offset);
 	}
-	return;
+        if (note_gnu_build_id && check_debuglink) {
+            ElfW(Nhdr) *nhdr = (ElfW(Nhdr)*) (file + note_gnu_build_id->sh_offset);
+            const char *build_id = (char *)(nhdr + 1) + nhdr->n_namesz;
+            follow_debuglink_build_id(build_id, nhdr->n_descsz,
+			       num_traces, traces,
+			       objp, lines, offset);
+        }
+	goto finish;
     }
 
-    parse_debug_line(num_traces, traces,
-		     file + debug_line_shdr->sh_offset,
-		     debug_line_shdr->sh_size,
-		     lines);
+    if (parse_debug_line(num_traces, traces,
+            obj->debug_line.ptr,
+            obj->debug_line.size,
+            obj, lines, offset) == -1)
+        goto fail;
+
+finish:
+    return dladdr_fbase;
+fail:
+    return (uintptr_t)-1;
 }
+#else /* Mach-O */
+/* read file and fill lines */
+static uintptr_t
+fill_lines(int num_traces, void **traces, int check_debuglink,
+        obj_info_t **objp, line_info_t *lines, int offset)
+{
+# ifdef __LP64__
+#  define LP(x) x##_64
+# else
+#  define LP(x) x
+# endif
+    int fd;
+    off_t filesize;
+    char *file, *p = NULL;
+    obj_info_t *obj = *objp;
+    struct LP(mach_header) *header;
+    uintptr_t dladdr_fbase = 0;
+
+    {
+        char *s = binary_filename;
+        char *base = strrchr(binary_filename, '/')+1;
+        size_t max = PATH_MAX;
+        size_t size = strlen(binary_filename);
+        size_t basesize = size - (base - binary_filename);
+        s += size;
+        max -= size;
+        p = s;
+        size = strlcpy(s, ".dSYM/Contents/Resources/DWARF/", max);
+        if (size == 0) goto fail;
+        s += size;
+        max -= size;
+        if (max <= basesize) goto fail;
+        memcpy(s, base, basesize);
+        s[basesize] = 0;
+
+        fd = open(binary_filename, O_RDONLY);
+        if (fd < 0) {
+            *p = 0; /* binary_filename becomes original file name */
+            fd = open(binary_filename, O_RDONLY);
+            if (fd < 0) {
+                goto fail;
+            }
+        }
+    }
 
-#ifdef HAVE_DL_ITERATE_PHDR
+    filesize = lseek(fd, 0, SEEK_END);
+    if (filesize < 0) {
+        int e = errno;
+        close(fd);
+        kprintf("lseek: %s\n", strerror(e));
+        goto fail;
+    }
+#if SIZEOF_OFF_T > SIZEOF_SIZE_T
+    if (filesize > (off_t)SIZE_MAX) {
+        close(fd);
+        kprintf("Too large file %s\n", binary_filename);
+        goto fail;
+    }
+#endif
+    lseek(fd, 0, SEEK_SET);
+    /* async-signal unsafe */
+    file = (char *)mmap(NULL, (size_t)filesize, PROT_READ, MAP_SHARED, fd, 0);
+    if (file == MAP_FAILED) {
+        int e = errno;
+        close(fd);
+        kprintf("mmap: %s\n", strerror(e));
+        goto fail;
+    }
+    close(fd);
 
-typedef struct {
-    int num_traces;
-    char **syms;
-    line_info_t *lines;
-} fill_base_addr_state_t;
+    obj->mapped = file;
+    obj->mapped_size = (size_t)filesize;
 
-static int
-fill_base_addr(struct dl_phdr_info *info, size_t size, void *data)
+    header = (struct LP(mach_header) *)file;
+    if (header->magic == LP(MH_MAGIC)) {
+        /* non universal binary */
+        p = file;
+    }
+    else if (header->magic == FAT_CIGAM) {
+        struct LP(mach_header) *mhp = _NSGetMachExecuteHeader();
+        struct fat_header *fat = (struct fat_header *)file;
+        char *q = file + sizeof(*fat);
+        uint32_t nfat_arch = __builtin_bswap32(fat->nfat_arch);
+        /* fprintf(stderr,"%d: fat:%s %d\n",__LINE__, binary_filename,nfat_arch); */
+        for (uint32_t i = 0; i < nfat_arch; i++) {
+            struct fat_arch *arch = (struct fat_arch *)q;
+            cpu_type_t cputype = __builtin_bswap32(arch->cputype);
+            cpu_subtype_t cpusubtype = __builtin_bswap32(arch->cpusubtype);
+            uint32_t offset = __builtin_bswap32(arch->offset);
+            /* fprintf(stderr,"%d: fat %d %x/%x %x/%x\n",__LINE__, i, mhp->cputype,mhp->cpusubtype, cputype,cpusubtype); */
+            if (mhp->cputype == cputype &&
+                    (cpu_subtype_t)(mhp->cpusubtype & ~CPU_SUBTYPE_MASK) == cpusubtype) {
+                p = file + offset;
+                file = p;
+                header = (struct LP(mach_header) *)p;
+                if (header->magic == LP(MH_MAGIC)) {
+                    goto found_mach_header;
+                }
+                break;
+            }
+            q += sizeof(*arch);
+        }
+        kprintf("'%s' is not a Mach-O universal binary file!\n",binary_filename);
+        close(fd);
+        goto fail;
+    }
+    else {
+        kprintf("'%s' is not a "
+# ifdef __LP64__
+                "64"
+# else
+                "32"
+# endif
+                "-bit Mach-O file!\n",binary_filename);
+        close(fd);
+        goto fail;
+    }
+found_mach_header:
+    p += sizeof(*header);
+
+    for (uint32_t i = 0; i < (uint32_t)header->ncmds; i++) {
+        struct load_command *lcmd = (struct load_command *)p;
+        switch (lcmd->cmd) {
+          case LP(LC_SEGMENT):
+            {
+                static const char *debug_section_names[] = {
+                    "__debug_abbrev",
+                    "__debug_info",
+                    "__debug_line",
+                    "__debug_ranges",
+                    "__debug_str_offsets",
+                    "__debug_addr",
+                    "__debug_rnglists",
+                    "__debug_str",
+                    "__debug_line_str",
+                };
+                struct LP(segment_command) *scmd = (struct LP(segment_command) *)lcmd;
+                if (strcmp(scmd->segname, "__TEXT") == 0) {
+                    obj->vmaddr = scmd->vmaddr;
+                }
+                else if (strcmp(scmd->segname, "__DWARF") == 0) {
+                    p += sizeof(struct LP(segment_command));
+                    for (uint64_t i = 0; i < scmd->nsects; i++) {
+                        struct LP(section) *sect = (struct LP(section) *)p;
+                        p += sizeof(struct LP(section));
+                        for (int j=0; j < DWARF_SECTION_COUNT; j++) {
+                            struct dwarf_section *s = obj_dwarf_section_at(obj, j);
+
+                            if (strcmp(sect->sectname, debug_section_names[j]) != 0)
+                                continue;
+
+                            s->ptr = file + sect->offset;
+                            s->size = sect->size;
+                            s->flags = sect->flags;
+                            if (s->flags & SHF_COMPRESSED) {
+                                goto fail;
+                            }
+                            break;
+                        }
+                    }
+                }
+            }
+            break;
+
+          case LC_SYMTAB:
+            {
+                struct symtab_command *cmd = (struct symtab_command *)lcmd;
+                struct LP(nlist) *nl = (struct LP(nlist) *)(file + cmd->symoff);
+                char *strtab = file + cmd->stroff, *sname = 0;
+                uint32_t j;
+                uintptr_t saddr = 0;
+                /* kprintf("[%2d]: %x/symtab %p\n", i, cmd->cmd, (void *)p); */
+                for (j = 0; j < cmd->nsyms; j++) {
+                    uintptr_t symsize, d;
+                    struct LP(nlist) *e = &nl[j];
+                        /* kprintf("[%2d][%4d]: %02x/%x/%x: %s %llx\n", i, j, e->n_type,e->n_sect,e->n_desc,strtab+e->n_un.n_strx,e->n_value); */
+                    if (e->n_type != N_FUN) continue;
+                    if (e->n_sect) {
+                        saddr = (uintptr_t)e->n_value + obj->base_addr - obj->vmaddr;
+                        sname = strtab + e->n_un.n_strx;
+                        /* kprintf("[%2d][%4d]: %02x/%x/%x: %s %llx\n", i, j, e->n_type,e->n_sect,e->n_desc,strtab+e->n_un.n_strx,e->n_value); */
+                        continue;
+                    }
+                    for (int k = offset; k < num_traces; k++) {
+                        d = (uintptr_t)traces[k] - saddr;
+                        symsize = e->n_value;
+                        /* kprintf("%lx %lx %lx\n",saddr,symsize,traces[k]); */
+                        if (lines[k].line > 0 || d > (uintptr_t)symsize)
+                            continue;
+                        /* fill symbol name and addr from .symtab */
+                        if (!lines[k].sname) lines[k].sname = sname;
+                        lines[k].saddr = saddr;
+                        lines[k].path  = obj->path;
+                        lines[k].base_addr = obj->base_addr;
+                    }
+                }
+            }
+        }
+        p += lcmd->cmdsize;
+    }
+
+    if (obj->debug_info.ptr && obj->debug_abbrev.ptr) {
+        DebugInfoReader reader;
+        debug_info_reader_init(&reader, obj);
+        while (reader.p < reader.pend) {
+            if (di_read_cu(&reader)) goto fail;
+            debug_info_read(&reader, num_traces, traces, lines, offset);
+        }
+    }
+
+    if (parse_debug_line(num_traces, traces,
+            obj->debug_line.ptr,
+            obj->debug_line.size,
+            obj, lines, offset) == -1)
+        goto fail;
+
+    return dladdr_fbase;
+fail:
+    return (uintptr_t)-1;
+}
+#endif
+
+#define HAVE_MAIN_EXE_PATH
+#if defined(__FreeBSD__) || defined(__DragonFly__)
+# include <sys/sysctl.h>
+#endif
+/* ssize_t main_exe_path(void)
+ *
+ * store the path of the main executable to `binary_filename`,
+ * and returns strlen(binary_filename).
+ * it is NUL terminated.
+ */
+#if defined(__linux__) || defined(__NetBSD__)
+static ssize_t
+main_exe_path(void)
 {
-    int i;
-    fill_base_addr_state_t *st = (fill_base_addr_state_t *)data;
-    for (i = 0; i < st->num_traces; i++) {
-	const char *path;
-	size_t len;
-	size_t name_len = strlen(info->dlpi_name);
-
-	if (get_path_from_symbol(st->syms[i], &path, &len) &&
-		(len == name_len || (len > name_len && path[len-name_len-1] == '/')) &&
-		!strncmp(path+len-name_len, info->dlpi_name, name_len)) {
-	    st->lines[i].base_addr = info->dlpi_addr;
-	}
+# if defined(__linux__)
+#  define PROC_SELF_EXE "/proc/self/exe"
+# elif defined(__NetBSD__)
+#  define PROC_SELF_EXE "/proc/curproc/exe"
+# endif
+    ssize_t len = readlink(PROC_SELF_EXE, binary_filename, PATH_MAX);
+    if (len < 0) return 0;
+    binary_filename[len] = 0;
+    return len;
+}
+#elif defined(__FreeBSD__) || defined(__DragonFly__)
+static ssize_t
+main_exe_path(void)
+{
+    int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
+    size_t len = PATH_MAX;
+    int err = sysctl(mib, 4, binary_filename, &len, NULL, 0);
+    if (err) {
+	kprintf("Can't get the path of ruby");
+	return -1;
+    }
+    len--; /* sysctl sets strlen+1 */
+    return len;
+}
+#elif defined(HAVE_LIBPROC_H)
+static ssize_t
+main_exe_path(void)
+{
+    int len = proc_pidpath(getpid(), binary_filename, PATH_MAX);
+    if (len == 0) return 0;
+    binary_filename[len] = 0;
+    return len;
+}
+#else
+#undef HAVE_MAIN_EXE_PATH
+#endif
+
+static void
+print_line0(line_info_t *line, void *address)
+{
+    uintptr_t addr = (uintptr_t)address;
+    uintptr_t d = addr - line->saddr;
+    if (!address) {
+        /* inlined */
+        if (line->dirname && line->dirname[0]) {
+            kprintf("%s(%s) %s/%s:%d\n", line->path, line->sname, line->dirname, line->filename, line->line);
+        }
+        else {
+            kprintf("%s(%s) %s:%d\n", line->path, line->sname, line->filename, line->line);
+        }
+    }
+    else if (!line->path) {
+        kprintf("[0x%"PRIxPTR"]\n", addr);
+    }
+    else if (!line->sname) {
+        kprintf("%s(0x%"PRIxPTR") [0x%"PRIxPTR"]\n", line->path, addr-line->base_addr, addr);
+    }
+    else if (!line->saddr) {
+        kprintf("%s(%s) [0x%"PRIxPTR"]\n", line->path, line->sname, addr);
+    }
+    else if (line->line <= 0) {
+        kprintf("%s(%s+0x%"PRIxPTR") [0x%"PRIxPTR"]\n", line->path, line->sname,
+                d, addr);
+    }
+    else if (!line->filename) {
+        kprintf("%s(%s+0x%"PRIxPTR") [0x%"PRIxPTR"] ???:%d\n", line->path, line->sname,
+                d, addr, line->line);
+    }
+    else if (line->dirname && line->dirname[0]) {
+        kprintf("%s(%s+0x%"PRIxPTR") [0x%"PRIxPTR"] %s/%s:%d\n", line->path, line->sname,
+                d, addr, line->dirname, line->filename, line->line);
+    }
+    else {
+        kprintf("%s(%s+0x%"PRIxPTR") [0x%"PRIxPTR"] %s:%d\n", line->path, line->sname,
+                d, addr, line->filename, line->line);
     }
-    return 0;
 }
 
-#endif /* HAVE_DL_ITERATE_PHDR */
+static void
+print_line(line_info_t *line, void *address)
+{
+    print_line0(line, address);
+    if (line->next) {
+        print_line(line->next, NULL);
+    }
+}
 
 void
-rb_dump_backtrace_with_lines(int num_traces, void **trace, char **syms)
+rb_dump_backtrace_with_lines(int num_traces, void **traces)
 {
     int i;
     /* async-signal unsafe */
-    line_info_t *lines = (line_info_t *)calloc(num_traces,
-					       sizeof(line_info_t));
-
-    /* Note that line info of shared objects might not be shown
-       if we don't have dl_iterate_phdr */
-#ifdef HAVE_DL_ITERATE_PHDR
-    fill_base_addr_state_t fill_base_addr_state;
-
-    fill_base_addr_state.num_traces = num_traces;
-    fill_base_addr_state.syms = syms;
-    fill_base_addr_state.lines = lines;
-    /* maybe async-signal unsafe */
-    dl_iterate_phdr(fill_base_addr, &fill_base_addr_state);
-#endif /* HAVE_DL_ITERATE_PHDR */
-
-    for (i = 0; i < num_traces; i++) {
-	const char *path;
-	size_t len;
-	if (lines[i].line) {
-	    continue;
-	}
-
-	if (!get_path_from_symbol(syms[i], &path, &len)) {
-	    continue;
+    line_info_t *lines = (line_info_t *)calloc(num_traces, sizeof(line_info_t));
+    obj_info_t *obj = NULL;
+    /* 2 is NULL + main executable */
+    void **dladdr_fbases = (void **)calloc(num_traces+2, sizeof(void *));
+
+#ifdef HAVE_MAIN_EXE_PATH
+    char *main_path = NULL; /* used on printing backtrace */
+    ssize_t len;
+    if ((len = main_exe_path()) > 0) {
+	main_path = (char *)alloca(len + 1);
+	if (main_path) {
+	    uintptr_t addr;
+	    memcpy(main_path, binary_filename, len+1);
+	    append_obj(&obj);
+	    obj->path = main_path;
+	    addr = fill_lines(num_traces, traces, 1, &obj, lines, -1);
+	    if (addr != (uintptr_t)-1) {
+		dladdr_fbases[0] = (void *)addr;
+	    }
 	}
-
-	strncpy(binary_filename, path, len);
-	binary_filename[len] = '\0';
-
-	fill_lines(num_traces, trace, syms, 1, &lines[i], lines);
     }
+#endif
 
+    /* fill source lines by reading dwarf */
     for (i = 0; i < num_traces; i++) {
-	line_info_t *line = &lines[i];
-
-	if (line->line > 0) {
-	    if (line->filename) {
-		if (line->dirname && line->dirname[0]) {
-		    kprintf("%s %s/%s:%d\n", syms[i], line->dirname, line->filename, line->line);
+	Dl_info info;
+	if (lines[i].line) continue;
+	if (dladdr(traces[i], &info)) {
+	    const char *path;
+	    void **p;
+
+	    /* skip symbols which is in already checked objects */
+	    /* if the binary is strip-ed, this may effect */
+	    for (p=dladdr_fbases; *p; p++) {
+		if (*p == info.dli_fbase) {
+		    if (info.dli_fname) lines[i].path = info.dli_fname;
+		    if (info.dli_sname) lines[i].sname = info.dli_sname;
+		    goto next_line;
 		}
-		else {
-		    kprintf("%s %s:%d\n", syms[i], line->filename, line->line);
-		}
-	    } else {
-		kprintf("%s ???:%d\n", syms[i], line->line);
 	    }
-	} else {
-	    kprintf("%s\n", syms[i]);
+	    *p = info.dli_fbase;
+
+	    append_obj(&obj);
+	    obj->base_addr = (uintptr_t)info.dli_fbase;
+	    path = info.dli_fname;
+	    obj->path = path;
+	    if (path) lines[i].path = path;
+            if (info.dli_sname) {
+                lines[i].sname = info.dli_sname;
+                lines[i].saddr = (uintptr_t)info.dli_saddr;
+            }
+	    strlcpy(binary_filename, path, PATH_MAX);
+	    if (fill_lines(num_traces, traces, 1, &obj, lines, i) == (uintptr_t)-1)
+		break;
 	}
+next_line:
+	continue;
     }
 
+    /* output */
     for (i = 0; i < num_traces; i++) {
-	line_info_t *line = &lines[i];
-	if (line->fd) {
-	    munmap(line->mapped, line->mapped_size);
-	    close(line->fd);
+        print_line(&lines[i], traces[i]);
+
+	/* FreeBSD's backtrace may show _start and so on */
+	if (lines[i].sname && strcmp("main", lines[i].sname) == 0)
+	    break;
+    }
+
+    /* free */
+    while (obj) {
+	obj_info_t *o = obj;
+        for (i=0; i < DWARF_SECTION_COUNT; i++) {
+            struct dwarf_section *s = obj_dwarf_section_at(obj, i);
+            if (s->flags & SHF_COMPRESSED) {
+                free(s->ptr);
+            }
+        }
+	if (obj->mapped_size) {
+	    munmap(obj->mapped, obj->mapped_size);
 	}
+	obj = o->next;
+	free(o);
+    }
+    for (i = 0; i < num_traces; i++) {
+        line_info_t *line = lines[i].next;
+        while (line) {
+            line_info_t *l = line;
+            line = line->next;
+            free(l);
+        }
     }
     free(lines);
+    free(dladdr_fbases);
 }
 
 /* From FreeBSD's lib/libstand/printf.c */
@@ -686,10 +2690,9 @@ rb_dump_backtrace_with_lines(int num_traces, void **trace, char **syms)
 
 #include <stdarg.h>
 #define MAXNBUF (sizeof(intmax_t) * CHAR_BIT + 1)
-extern int rb_toupper(int c);
-#define    toupper(c)  rb_toupper(c)
+static inline int toupper(int c) { return ('A' <= c && c <= 'Z') ? (c&0x5f) : c; }
 #define    hex2ascii(hex)  (hex2ascii_data[hex])
-char const hex2ascii_data[] = "0123456789abcdefghijklmnopqrstuvwxyz";
+static const char hex2ascii_data[] = "0123456789abcdefghijklmnopqrstuvwxyz";
 static inline int imax(int a, int b) { return (a > b ? a : b); }
 static int kvprintf(char const *fmt, void (*func)(int), void *arg, int radix, va_list ap);
 
@@ -703,7 +2706,7 @@ static void putce(int c)
     (void)ret;
 }
 
-int
+static int
 kprintf(const char *fmt, ...)
 {
 	va_list ap;
diff --git a/addr2line.h b/addr2line.h
index 3782d89e07..f09b665800 100644
--- a/addr2line.h
+++ b/addr2line.h
@@ -1,3 +1,5 @@
+#ifndef RUBY_ADDR2LINE_H
+#define RUBY_ADDR2LINE_H
 /**********************************************************************
 
   addr2line.h -
@@ -8,13 +10,10 @@
 
 **********************************************************************/
 
-#ifndef RUBY_ADDR2LINE_H
-#define RUBY_ADDR2LINE_H
-
-#ifdef USE_ELF
+#if (defined(USE_ELF) || defined(HAVE_MACH_O_LOADER_H))
 
 void
-rb_dump_backtrace_with_lines(int num_traces, void **traces, char **syms);
+rb_dump_backtrace_with_lines(int num_traces, void **traces);
 
 #endif /* USE_ELF */
 
diff --git a/array.c b/array.c
index 088a9a5f1a..b76e9a64a3 100644
--- a/array.c
+++ b/array.c
@@ -11,117 +11,107 @@
 
 **********************************************************************/
 
-#include "ruby/ruby.h"
-#include "ruby/util.h"
-#include "ruby/st.h"
-#include "ruby/encoding.h"
+#include "debug_counter.h"
+#include "id.h"
 #include "internal.h"
+#include "internal/array.h"
+#include "internal/compar.h"
+#include "internal/enum.h"
+#include "internal/gc.h"
+#include "internal/hash.h"
+#include "internal/numeric.h"
+#include "internal/object.h"
+#include "internal/proc.h"
+#include "internal/rational.h"
+#include "internal/vm.h"
 #include "probes.h"
-#include "id.h"
+#include "ruby/encoding.h"
+#include "ruby/st.h"
+#include "ruby/util.h"
+#include "transient_heap.h"
+#include "builtin.h"
 
-#ifndef ARRAY_DEBUG
+#if !ARRAY_DEBUG
+# undef NDEBUG
 # define NDEBUG
 #endif
-#include <assert.h>
+#include "ruby_assert.h"
 
 VALUE rb_cArray;
 
-static ID id_cmp, id_div, id_power;
+/* Flags of RArray
+ *
+ * 1:   RARRAY_EMBED_FLAG
+ *          The array is embedded (its contents follow the header, rather than
+ *          being on a separately allocated buffer).
+ * 2:   RARRAY_SHARED_FLAG (equal to ELTS_SHARED)
+ *          The array is shared. The buffer this array points to is owned by
+ *          another array (the shared root).
+ * if USE_RVARGC
+ * 3-9: RARRAY_EMBED_LEN
+ *          The length of the array when RARRAY_EMBED_FLAG is set.
+ * else
+ * 3-4: RARRAY_EMBED_LEN
+ *          The length of the array when RARRAY_EMBED_FLAG is set.
+ * endif
+ * 12:  RARRAY_SHARED_ROOT_FLAG
+ *          The array is a shared root that does reference counting. The buffer
+ *          this array points to is owned by this array but may be pointed to
+ *          by other arrays.
+ *          Note: Frozen arrays may be a shared root without this flag being
+ *                set. Frozen arrays do not have reference counting because
+ *                they cannot be modified. Not updating the reference count
+ *                improves copy-on-write performance. Their reference count is
+ *                assumed to be infinity.
+ * 13:  RARRAY_TRANSIENT_FLAG
+ *          The buffer of the array is allocated on the transient heap.
+ * 14:  RARRAY_PTR_IN_USE_FLAG
+ *          The buffer of the array is in use. This is only used during
+ *          debugging.
+ */
+
+/* for OPTIMIZED_CMP: */
+#define id_cmp idCmp
 
 #define ARY_DEFAULT_SIZE 16
 #define ARY_MAX_SIZE (LONG_MAX / (int)sizeof(VALUE))
+#define SMALL_ARRAY_LEN 16
 
-void
-rb_mem_clear(register VALUE *mem, register long size)
-{
-    while (size--) {
-	*mem++ = Qnil;
-    }
-}
-
-static void
-ary_mem_clear(VALUE ary, long beg, long size)
-{
-    RARRAY_PTR_USE(ary, ptr, {
-	rb_mem_clear(ptr + beg, size);
-    });
-}
-
-static inline void
-memfill(register VALUE *mem, register long size, register VALUE val)
-{
-    while (size--) {
-	*mem++ = val;
-    }
-}
-
-static void
-ary_memfill(VALUE ary, long beg, long size, VALUE val)
-{
-    RARRAY_PTR_USE(ary, ptr, {
-	memfill(ptr + beg, size, val);
-	RB_OBJ_WRITTEN(ary, Qundef, val);
-    });
-}
-
-static void
-ary_memcpy(VALUE ary, long beg, long argc, const VALUE *argv)
+RBIMPL_ATTR_MAYBE_UNUSED()
+static int
+should_be_T_ARRAY(VALUE ary)
 {
-#if 1
-    if (OBJ_PROMOTED(ary)) {
-	if (argc > (int)(128/sizeof(VALUE)) /* is magic number (cache line size) */) {
-	    rb_gc_writebarrier_remember_promoted(ary);
-	    RARRAY_PTR_USE(ary, ptr, {
-		MEMCPY(ptr+beg, argv, VALUE, argc);
-	    });
-	}
-	else {
-	    int i;
-	    RARRAY_PTR_USE(ary, ptr, {
-		for (i=0; i<argc; i++) {
-		    RB_OBJ_WRITE(ary, &ptr[i+beg], argv[i]);
-		}
-	    });
-	}
-    }
-    else {
-	RARRAY_PTR_USE(ary, ptr, {
-	    MEMCPY(ptr+beg, argv, VALUE, argc);
-	});
-    }
-#else
-    /* giveup write barrier (traditional way) */
-    MEMCPY(RARRAY_PTR(ary)+beg, argv, VALUE, argc);
-#endif
+    return RB_TYPE_P(ary, T_ARRAY);
 }
 
-# define ARY_SHARED_P(ary) \
-    (assert(!FL_TEST((ary), ELTS_SHARED) || !FL_TEST((ary), RARRAY_EMBED_FLAG)), \
-     FL_TEST((ary),ELTS_SHARED)!=0)
-# define ARY_EMBED_P(ary) \
-    (assert(!FL_TEST((ary), ELTS_SHARED) || !FL_TEST((ary), RARRAY_EMBED_FLAG)), \
-     FL_TEST((ary), RARRAY_EMBED_FLAG)!=0)
-
 #define ARY_HEAP_PTR(a) (assert(!ARY_EMBED_P(a)), RARRAY(a)->as.heap.ptr)
 #define ARY_HEAP_LEN(a) (assert(!ARY_EMBED_P(a)), RARRAY(a)->as.heap.len)
+#define ARY_HEAP_CAPA(a) (assert(!ARY_EMBED_P(a)), assert(!ARY_SHARED_ROOT_P(a)), \
+                          RARRAY(a)->as.heap.aux.capa)
+
 #define ARY_EMBED_PTR(a) (assert(ARY_EMBED_P(a)), RARRAY(a)->as.ary)
 #define ARY_EMBED_LEN(a) \
     (assert(ARY_EMBED_P(a)), \
      (long)((RBASIC(a)->flags >> RARRAY_EMBED_LEN_SHIFT) & \
-	 (RARRAY_EMBED_LEN_MASK >> RARRAY_EMBED_LEN_SHIFT)))
-#define ARY_HEAP_SIZE(a) (assert(!ARY_EMBED_P(a)), assert(ARY_OWNS_HEAP_P(a)), RARRAY(a)->as.heap.aux.capa * sizeof(VALUE))
+         (RARRAY_EMBED_LEN_MASK >> RARRAY_EMBED_LEN_SHIFT)))
+#define ARY_HEAP_SIZE(a) (assert(!ARY_EMBED_P(a)), assert(ARY_OWNS_HEAP_P(a)), ARY_CAPA(a) * sizeof(VALUE))
+
+#define ARY_OWNS_HEAP_P(a) (assert(should_be_T_ARRAY((VALUE)(a))), \
+                            !FL_TEST_RAW((a), RARRAY_SHARED_FLAG|RARRAY_EMBED_FLAG))
 
-#define ARY_OWNS_HEAP_P(a) (!FL_TEST((a), ELTS_SHARED|RARRAY_EMBED_FLAG))
 #define FL_SET_EMBED(a) do { \
     assert(!ARY_SHARED_P(a)); \
     FL_SET((a), RARRAY_EMBED_FLAG); \
+    RARY_TRANSIENT_UNSET(a); \
+    ary_verify(a); \
 } while (0)
+
 #define FL_UNSET_EMBED(ary) FL_UNSET((ary), RARRAY_EMBED_FLAG|RARRAY_EMBED_LEN_MASK)
 #define FL_SET_SHARED(ary) do { \
     assert(!ARY_EMBED_P(ary)); \
-    FL_SET((ary), ELTS_SHARED); \
+    FL_SET((ary), RARRAY_SHARED_FLAG); \
 } while (0)
-#define FL_UNSET_SHARED(ary) FL_UNSET((ary), ELTS_SHARED)
+#define FL_UNSET_SHARED(ary) FL_UNSET((ary), RARRAY_SHARED_FLAG)
 
 #define ARY_SET_PTR(ary, p) do { \
     assert(!ARY_EMBED_P(ary)); \
@@ -131,7 +121,6 @@ ary_memcpy(VALUE ary, long beg, long argc, const VALUE *argv)
 #define ARY_SET_EMBED_LEN(ary, n) do { \
     long tmp_n = (n); \
     assert(ARY_EMBED_P(ary)); \
-    assert(!OBJ_FROZEN(ary)); \
     RBASIC(ary)->flags &= ~RARRAY_EMBED_LEN_MASK; \
     RBASIC(ary)->flags |= (tmp_n) << RARRAY_EMBED_LEN_SHIFT; \
 } while (0)
@@ -163,8 +152,8 @@ ary_memcpy(VALUE ary, long beg, long argc, const VALUE *argv)
     } \
 } while (0)
 
-#define ARY_CAPA(ary) (ARY_EMBED_P(ary) ? RARRAY_EMBED_LEN_MAX : \
-		       ARY_SHARED_ROOT_P(ary) ? RARRAY_LEN(ary) : RARRAY(ary)->as.heap.aux.capa)
+#define ARY_CAPA(ary) (ARY_EMBED_P(ary) ? ary_embed_capa(ary) : \
+                       ARY_SHARED_ROOT_P(ary) ? RARRAY_LEN(ary) : ARY_HEAP_CAPA(ary))
 #define ARY_SET_CAPA(ary, n) do { \
     assert(!ARY_EMBED_P(ary)); \
     assert(!ARY_SHARED_P(ary)); \
@@ -172,72 +161,424 @@ ary_memcpy(VALUE ary, long beg, long argc, const VALUE *argv)
     RARRAY(ary)->as.heap.aux.capa = (n); \
 } while (0)
 
-#define ARY_SHARED(ary) (assert(ARY_SHARED_P(ary)), RARRAY(ary)->as.heap.aux.shared)
 #define ARY_SET_SHARED(ary, value) do { \
     const VALUE _ary_ = (ary); \
     const VALUE _value_ = (value); \
     assert(!ARY_EMBED_P(_ary_)); \
     assert(ARY_SHARED_P(_ary_)); \
-    assert(ARY_SHARED_ROOT_P(_value_)); \
-    RB_OBJ_WRITE(_ary_, &RARRAY(_ary_)->as.heap.aux.shared, _value_); \
+    assert(!OBJ_FROZEN(_ary_)); \
+    assert(ARY_SHARED_ROOT_P(_value_) || OBJ_FROZEN(_value_)); \
+    RB_OBJ_WRITE(_ary_, &RARRAY(_ary_)->as.heap.aux.shared_root, _value_); \
 } while (0)
-#define RARRAY_SHARED_ROOT_FLAG FL_USER5
-#define ARY_SHARED_ROOT_P(ary) (FL_TEST((ary), RARRAY_SHARED_ROOT_FLAG))
-#define ARY_SHARED_NUM(ary) \
-    (assert(ARY_SHARED_ROOT_P(ary)), RARRAY(ary)->as.heap.aux.capa)
-#define ARY_SHARED_OCCUPIED(ary) (ARY_SHARED_NUM(ary) == 1)
-#define ARY_SET_SHARED_NUM(ary, value) do { \
+
+#define ARY_SHARED_ROOT_OCCUPIED(ary) (!OBJ_FROZEN(ary) && ARY_SHARED_ROOT_REFCNT(ary) == 1)
+#define ARY_SET_SHARED_ROOT_REFCNT(ary, value) do { \
     assert(ARY_SHARED_ROOT_P(ary)); \
+    assert(!OBJ_FROZEN(ary)); \
+    assert((value) >= 0); \
     RARRAY(ary)->as.heap.aux.capa = (value); \
 } while (0)
 #define FL_SET_SHARED_ROOT(ary) do { \
+    assert(!OBJ_FROZEN(ary)); \
     assert(!ARY_EMBED_P(ary)); \
+    assert(!RARRAY_TRANSIENT_P(ary)); \
     FL_SET((ary), RARRAY_SHARED_ROOT_FLAG); \
 } while (0)
 
+static inline void
+ARY_SET(VALUE a, long i, VALUE v)
+{
+    assert(!ARY_SHARED_P(a));
+    assert(!OBJ_FROZEN(a));
+
+    RARRAY_ASET(a, i, v);
+}
+#undef RARRAY_ASET
+
+static long
+ary_embed_capa(VALUE ary)
+{
+#if USE_RVARGC
+    size_t size = rb_gc_obj_slot_size(ary) - offsetof(struct RArray, as.ary);
+    assert(size % sizeof(VALUE) == 0);
+    return size / sizeof(VALUE);
+#else
+    return RARRAY_EMBED_LEN_MAX;
+#endif
+}
+
+static size_t
+ary_embed_size(long capa)
+{
+    return offsetof(struct RArray, as.ary) + (sizeof(VALUE) * capa);
+}
+
+static bool
+ary_embeddable_p(long capa)
+{
+#if USE_RVARGC
+    return rb_gc_size_allocatable_p(ary_embed_size(capa));
+#else
+    return capa <= RARRAY_EMBED_LEN_MAX;
+#endif
+}
+
+bool
+rb_ary_embeddable_p(VALUE ary)
+{
+    /* An array cannot be turned embeddable when the array is:
+     *  - Shared root: other objects may point to the buffer of this array
+     *    so we cannot make it embedded.
+     *  - Frozen: this array may also be a shared root without the shared root
+     *    flag.
+     *  - Shared: we don't want to re-embed an array that points to a shared
+     *    root (to save memory).
+     */
+    return !(ARY_SHARED_ROOT_P(ary) || OBJ_FROZEN(ary) || ARY_SHARED_P(ary));
+}
+
+size_t
+rb_ary_size_as_embedded(VALUE ary)
+{
+    size_t real_size;
+
+    if (ARY_EMBED_P(ary)) {
+        real_size = ary_embed_size(ARY_EMBED_LEN(ary));
+    }
+    else if (rb_ary_embeddable_p(ary)) {
+        real_size = ary_embed_size(ARY_HEAP_CAPA(ary));
+    }
+    else {
+        real_size = sizeof(struct RArray);
+    }
+    return real_size;
+}
+
+
+#if ARRAY_DEBUG
+#define ary_verify(ary) ary_verify_(ary, __FILE__, __LINE__)
+
+static VALUE
+ary_verify_(VALUE ary, const char *file, int line)
+{
+    assert(RB_TYPE_P(ary, T_ARRAY));
+
+    if (ARY_SHARED_P(ary)) {
+        VALUE root = ARY_SHARED_ROOT(ary);
+        const VALUE *ptr = ARY_HEAP_PTR(ary);
+        const VALUE *root_ptr = RARRAY_CONST_PTR_TRANSIENT(root);
+        long len = ARY_HEAP_LEN(ary), root_len = RARRAY_LEN(root);
+        assert(ARY_SHARED_ROOT_P(root) || OBJ_FROZEN(root));
+        assert(root_ptr <= ptr && ptr + len <= root_ptr + root_len);
+        ary_verify(root);
+    }
+    else if (ARY_EMBED_P(ary)) {
+        assert(!RARRAY_TRANSIENT_P(ary));
+        assert(!ARY_SHARED_P(ary));
+        assert(RARRAY_LEN(ary) <= ary_embed_capa(ary));
+    }
+    else {
+#if 1
+        const VALUE *ptr = RARRAY_CONST_PTR_TRANSIENT(ary);
+        long i, len = RARRAY_LEN(ary);
+        volatile VALUE v;
+        if (len > 1) len = 1; /* check only HEAD */
+        for (i=0; i<len; i++) {
+            v = ptr[i]; /* access check */
+        }
+        v = v;
+#endif
+    }
+
+#if USE_TRANSIENT_HEAP
+    if (RARRAY_TRANSIENT_P(ary)) {
+        assert(rb_transient_heap_managed_ptr_p(RARRAY_CONST_PTR_TRANSIENT(ary)));
+    }
+#endif
+
+    rb_transient_heap_verify();
+
+    return ary;
+}
+
+void
+rb_ary_verify(VALUE ary)
+{
+    ary_verify(ary);
+}
+#else
+#define ary_verify(ary) ((void)0)
+#endif
+
+VALUE *
+rb_ary_ptr_use_start(VALUE ary)
+{
+#if ARRAY_DEBUG
+    FL_SET_RAW(ary, RARRAY_PTR_IN_USE_FLAG);
+#endif
+    return (VALUE *)RARRAY_CONST_PTR_TRANSIENT(ary);
+}
+
+void
+rb_ary_ptr_use_end(VALUE ary)
+{
+#if ARRAY_DEBUG
+    FL_UNSET_RAW(ary, RARRAY_PTR_IN_USE_FLAG);
+#endif
+}
+
+void
+rb_mem_clear(VALUE *mem, long size)
+{
+    while (size--) {
+        *mem++ = Qnil;
+    }
+}
+
+static void
+ary_mem_clear(VALUE ary, long beg, long size)
+{
+    RARRAY_PTR_USE_TRANSIENT(ary, ptr, {
+        rb_mem_clear(ptr + beg, size);
+    });
+}
+
+static inline void
+memfill(register VALUE *mem, register long size, register VALUE val)
+{
+    while (size--) {
+        *mem++ = val;
+    }
+}
+
+static void
+ary_memfill(VALUE ary, long beg, long size, VALUE val)
+{
+    RARRAY_PTR_USE_TRANSIENT(ary, ptr, {
+        memfill(ptr + beg, size, val);
+        RB_OBJ_WRITTEN(ary, Qundef, val);
+    });
+}
+
+static void
+ary_memcpy0(VALUE ary, long beg, long argc, const VALUE *argv, VALUE buff_owner_ary)
+{
+    assert(!ARY_SHARED_P(buff_owner_ary));
+
+    if (argc > (int)(128/sizeof(VALUE)) /* is magic number (cache line size) */) {
+        rb_gc_writebarrier_remember(buff_owner_ary);
+        RARRAY_PTR_USE_TRANSIENT(ary, ptr, {
+            MEMCPY(ptr+beg, argv, VALUE, argc);
+        });
+    }
+    else {
+        int i;
+        RARRAY_PTR_USE_TRANSIENT(ary, ptr, {
+            for (i=0; i<argc; i++) {
+                RB_OBJ_WRITE(buff_owner_ary, &ptr[i+beg], argv[i]);
+            }
+        });
+    }
+}
+
+static void
+ary_memcpy(VALUE ary, long beg, long argc, const VALUE *argv)
+{
+    ary_memcpy0(ary, beg, argc, argv, ary);
+}
+
+static VALUE *
+ary_heap_alloc(VALUE ary, size_t capa)
+{
+    VALUE *ptr = rb_transient_heap_alloc(ary, sizeof(VALUE) * capa);
+
+    if (ptr != NULL) {
+        RARY_TRANSIENT_SET(ary);
+    }
+    else {
+        RARY_TRANSIENT_UNSET(ary);
+        ptr = ALLOC_N(VALUE, capa);
+    }
+
+    return ptr;
+}
+
+static void
+ary_heap_free_ptr(VALUE ary, const VALUE *ptr, long size)
+{
+    if (RARRAY_TRANSIENT_P(ary)) {
+        /* ignore it */
+    }
+    else {
+        ruby_sized_xfree((void *)ptr, size);
+    }
+}
+
+static void
+ary_heap_free(VALUE ary)
+{
+    if (RARRAY_TRANSIENT_P(ary)) {
+        RARY_TRANSIENT_UNSET(ary);
+    }
+    else {
+        ary_heap_free_ptr(ary, ARY_HEAP_PTR(ary), ARY_HEAP_SIZE(ary));
+    }
+}
+
+static size_t
+ary_heap_realloc(VALUE ary, size_t new_capa)
+{
+    size_t alloc_capa = new_capa;
+    size_t old_capa = ARY_HEAP_CAPA(ary);
+
+    if (RARRAY_TRANSIENT_P(ary)) {
+        if (new_capa <= old_capa) {
+            /* do nothing */
+            alloc_capa = old_capa;
+        }
+        else {
+            VALUE *new_ptr = rb_transient_heap_alloc(ary, sizeof(VALUE) * new_capa);
+
+            if (new_ptr == NULL) {
+                new_ptr = ALLOC_N(VALUE, new_capa);
+                RARY_TRANSIENT_UNSET(ary);
+            }
+
+            MEMCPY(new_ptr, ARY_HEAP_PTR(ary), VALUE, old_capa);
+            ARY_SET_PTR(ary, new_ptr);
+        }
+    }
+    else {
+        SIZED_REALLOC_N(RARRAY(ary)->as.heap.ptr, VALUE, new_capa, old_capa);
+    }
+    ary_verify(ary);
+
+    return alloc_capa;
+}
+
+#if USE_TRANSIENT_HEAP
+static inline void
+rb_ary_transient_heap_evacuate_(VALUE ary, int transient, int promote)
+{
+    if (transient) {
+        assert(!ARY_SHARED_ROOT_P(ary));
+
+        VALUE *new_ptr;
+        const VALUE *old_ptr = ARY_HEAP_PTR(ary);
+        long capa = ARY_HEAP_CAPA(ary);
+
+        assert(ARY_OWNS_HEAP_P(ary));
+        assert(RARRAY_TRANSIENT_P(ary));
+        assert(!ARY_PTR_USING_P(ary));
+
+        if (promote) {
+            new_ptr = ALLOC_N(VALUE, capa);
+            RARY_TRANSIENT_UNSET(ary);
+        }
+        else {
+            new_ptr = ary_heap_alloc(ary, capa);
+        }
+
+        MEMCPY(new_ptr, old_ptr, VALUE, capa);
+        /* do not use ARY_SET_PTR() because they assert !frozen */
+        RARRAY(ary)->as.heap.ptr = new_ptr;
+    }
+
+    ary_verify(ary);
+}
+
+void
+rb_ary_transient_heap_evacuate(VALUE ary, int promote)
+{
+    rb_ary_transient_heap_evacuate_(ary, RARRAY_TRANSIENT_P(ary), promote);
+}
+
+void
+rb_ary_detransient(VALUE ary)
+{
+    assert(RARRAY_TRANSIENT_P(ary));
+    rb_ary_transient_heap_evacuate_(ary, TRUE, TRUE);
+}
+#else
+void
+rb_ary_detransient(VALUE ary)
+{
+    /* do nothing */
+}
+#endif
+
+void
+rb_ary_make_embedded(VALUE ary)
+{
+    assert(rb_ary_embeddable_p(ary));
+    if (!ARY_EMBED_P(ary)) {
+        const VALUE *buf = ARY_HEAP_PTR(ary);
+        long len = ARY_HEAP_LEN(ary);
+        bool was_transient = RARRAY_TRANSIENT_P(ary);
+
+        // FL_SET_EMBED also unsets the transient flag
+        FL_SET_EMBED(ary);
+        ARY_SET_EMBED_LEN(ary, len);
+
+        MEMCPY((void *)ARY_EMBED_PTR(ary), (void *)buf, VALUE, len);
+
+        if (!was_transient) {
+            ary_heap_free_ptr(ary, buf, len * sizeof(VALUE));
+        }
+    }
+}
+
 static void
 ary_resize_capa(VALUE ary, long capacity)
 {
     assert(RARRAY_LEN(ary) <= capacity);
     assert(!OBJ_FROZEN(ary));
     assert(!ARY_SHARED_P(ary));
-    if (capacity > RARRAY_EMBED_LEN_MAX) {
+
+    if (capacity > ary_embed_capa(ary)) {
+        size_t new_capa = capacity;
         if (ARY_EMBED_P(ary)) {
             long len = ARY_EMBED_LEN(ary);
-            VALUE *ptr = ALLOC_N(VALUE, (capacity));
+            VALUE *ptr = ary_heap_alloc(ary, capacity);
+
             MEMCPY(ptr, ARY_EMBED_PTR(ary), VALUE, len);
             FL_UNSET_EMBED(ary);
             ARY_SET_PTR(ary, ptr);
             ARY_SET_HEAP_LEN(ary, len);
         }
         else {
-	    SIZED_REALLOC_N(RARRAY(ary)->as.heap.ptr, VALUE, capacity, RARRAY(ary)->as.heap.aux.capa);
+            new_capa = ary_heap_realloc(ary, capacity);
         }
-        ARY_SET_CAPA(ary, (capacity));
+        ARY_SET_CAPA(ary, new_capa);
     }
     else {
         if (!ARY_EMBED_P(ary)) {
-            long len = RARRAY_LEN(ary);
-	    const VALUE *ptr = RARRAY_CONST_PTR(ary);
+            long len = ARY_HEAP_LEN(ary);
+            long old_capa = ARY_HEAP_CAPA(ary);
+            const VALUE *ptr = ARY_HEAP_PTR(ary);
 
-	    if (len > capacity) len = capacity;
+            if (len > capacity) len = capacity;
             MEMCPY((VALUE *)RARRAY(ary)->as.ary, ptr, VALUE, len);
+            ary_heap_free_ptr(ary, ptr, old_capa);
+
             FL_SET_EMBED(ary);
             ARY_SET_LEN(ary, len);
-	    ruby_xfree((VALUE *)ptr);
         }
     }
+
+    ary_verify(ary);
 }
 
 static inline void
 ary_shrink_capa(VALUE ary)
 {
     long capacity = ARY_HEAP_LEN(ary);
-    long old_capa = RARRAY(ary)->as.heap.aux.capa;
+    long old_capa = ARY_HEAP_CAPA(ary);
     assert(!ARY_SHARED_P(ary));
     assert(old_capa >= capacity);
-    if (old_capa > capacity)
-	REALLOC_N(RARRAY(ary)->as.heap.ptr, VALUE, capacity);
+    if (old_capa > capacity) ary_heap_realloc(ary, capacity);
+
+    ary_verify(ary);
 }
 
 static void
@@ -246,146 +587,183 @@ ary_double_capa(VALUE ary, long min)
     long new_capa = ARY_CAPA(ary) / 2;
 
     if (new_capa < ARY_DEFAULT_SIZE) {
-	new_capa = ARY_DEFAULT_SIZE;
+        new_capa = ARY_DEFAULT_SIZE;
     }
     if (new_capa >= ARY_MAX_SIZE - min) {
-	new_capa = (ARY_MAX_SIZE - min) / 2;
+        new_capa = (ARY_MAX_SIZE - min) / 2;
     }
     new_capa += min;
     ary_resize_capa(ary, new_capa);
+
+    ary_verify(ary);
 }
 
 static void
-rb_ary_decrement_share(VALUE shared)
+rb_ary_decrement_share(VALUE shared_root)
 {
-    if (shared) {
-	long num = ARY_SHARED_NUM(shared) - 1;
-	if (num == 0) {
-	    rb_ary_free(shared);
-	    rb_gc_force_recycle(shared);
-	}
-	else if (num > 0) {
-	    ARY_SET_SHARED_NUM(shared, num);
-	}
+    if (!OBJ_FROZEN(shared_root)) {
+        long num = ARY_SHARED_ROOT_REFCNT(shared_root);
+        ARY_SET_SHARED_ROOT_REFCNT(shared_root, num - 1);
     }
 }
 
 static void
 rb_ary_unshare(VALUE ary)
 {
-    VALUE shared = RARRAY(ary)->as.heap.aux.shared;
-    rb_ary_decrement_share(shared);
+    VALUE shared_root = ARY_SHARED_ROOT(ary);
+    rb_ary_decrement_share(shared_root);
     FL_UNSET_SHARED(ary);
 }
 
-static inline void
-rb_ary_unshare_safe(VALUE ary)
+static void
+rb_ary_reset(VALUE ary)
 {
-    if (ARY_SHARED_P(ary) && !ARY_EMBED_P(ary)) {
-	rb_ary_unshare(ary);
+    if (ARY_OWNS_HEAP_P(ary)) {
+        ary_heap_free(ary);
+    }
+    else if (ARY_SHARED_P(ary)) {
+        rb_ary_unshare(ary);
     }
+
+    FL_SET_EMBED(ary);
+    ARY_SET_EMBED_LEN(ary, 0);
 }
 
 static VALUE
-rb_ary_increment_share(VALUE shared)
+rb_ary_increment_share(VALUE shared_root)
 {
-    long num = ARY_SHARED_NUM(shared);
-    if (num >= 0) {
-	ARY_SET_SHARED_NUM(shared, num + 1);
+    if (!OBJ_FROZEN(shared_root)) {
+        long num = ARY_SHARED_ROOT_REFCNT(shared_root);
+        assert(num >= 0);
+        ARY_SET_SHARED_ROOT_REFCNT(shared_root, num + 1);
     }
-    return shared;
+    return shared_root;
 }
 
 static void
-rb_ary_set_shared(VALUE ary, VALUE shared)
+rb_ary_set_shared(VALUE ary, VALUE shared_root)
 {
-    rb_ary_increment_share(shared);
+    rb_ary_increment_share(shared_root);
     FL_SET_SHARED(ary);
-    ARY_SET_SHARED(ary, shared);
+    RB_DEBUG_COUNTER_INC(obj_ary_shared_create);
+    ARY_SET_SHARED(ary, shared_root);
 }
 
 static inline void
 rb_ary_modify_check(VALUE ary)
 {
     rb_check_frozen(ary);
+    ary_verify(ary);
 }
 
 void
-rb_ary_modify(VALUE ary)
+rb_ary_cancel_sharing(VALUE ary)
 {
-    rb_ary_modify_check(ary);
     if (ARY_SHARED_P(ary)) {
-	long shared_len, len = RARRAY_LEN(ary);
-	VALUE shared = ARY_SHARED(ary);
-        if (len <= RARRAY_EMBED_LEN_MAX) {
-	    const VALUE *ptr = ARY_HEAP_PTR(ary);
+        long shared_len, len = RARRAY_LEN(ary);
+        VALUE shared_root = ARY_SHARED_ROOT(ary);
+
+        ary_verify(shared_root);
+
+        if (len <= ary_embed_capa(ary)) {
+            const VALUE *ptr = ARY_HEAP_PTR(ary);
             FL_UNSET_SHARED(ary);
             FL_SET_EMBED(ary);
-	    MEMCPY((VALUE *)ARY_EMBED_PTR(ary), ptr, VALUE, len);
-            rb_ary_decrement_share(shared);
+            MEMCPY((VALUE *)ARY_EMBED_PTR(ary), ptr, VALUE, len);
+            rb_ary_decrement_share(shared_root);
             ARY_SET_EMBED_LEN(ary, len);
         }
-	else if (ARY_SHARED_OCCUPIED(shared) && len > ((shared_len = RARRAY_LEN(shared))>>1)) {
-	    long shift = RARRAY_CONST_PTR(ary) - RARRAY_CONST_PTR(shared);
-	    FL_UNSET_SHARED(ary);
-	    ARY_SET_PTR(ary, RARRAY_CONST_PTR(shared));
-	    ARY_SET_CAPA(ary, shared_len);
-	    RARRAY_PTR_USE(ary, ptr, {
-		MEMMOVE(ptr, ptr+shift, VALUE, len);
-	    });
-	    FL_SET_EMBED(shared);
-	    rb_ary_decrement_share(shared);
-	}
+        else if (ARY_SHARED_ROOT_OCCUPIED(shared_root) && len > ((shared_len = RARRAY_LEN(shared_root))>>1)) {
+            long shift = RARRAY_CONST_PTR_TRANSIENT(ary) - RARRAY_CONST_PTR_TRANSIENT(shared_root);
+            FL_UNSET_SHARED(ary);
+            ARY_SET_PTR(ary, RARRAY_CONST_PTR_TRANSIENT(shared_root));
+            ARY_SET_CAPA(ary, shared_len);
+            RARRAY_PTR_USE_TRANSIENT(ary, ptr, {
+                MEMMOVE(ptr, ptr+shift, VALUE, len);
+            });
+            FL_SET_EMBED(shared_root);
+            rb_ary_decrement_share(shared_root);
+        }
         else {
-            VALUE *ptr = ALLOC_N(VALUE, len);
-            MEMCPY(ptr, RARRAY_CONST_PTR(ary), VALUE, len);
+            VALUE *ptr = ary_heap_alloc(ary, len);
+            MEMCPY(ptr, ARY_HEAP_PTR(ary), VALUE, len);
             rb_ary_unshare(ary);
             ARY_SET_CAPA(ary, len);
             ARY_SET_PTR(ary, ptr);
         }
+
+        rb_gc_writebarrier_remember(ary);
     }
+    ary_verify(ary);
 }
 
-static void
+void
+rb_ary_modify(VALUE ary)
+{
+    rb_ary_modify_check(ary);
+    rb_ary_cancel_sharing(ary);
+}
+
+static VALUE
 ary_ensure_room_for_push(VALUE ary, long add_len)
 {
-    long new_len = RARRAY_LEN(ary) + add_len;
+    long old_len = RARRAY_LEN(ary);
+    long new_len = old_len + add_len;
     long capa;
 
+    if (old_len > ARY_MAX_SIZE - add_len) {
+        rb_raise(rb_eIndexError, "index %ld too big", new_len);
+    }
     if (ARY_SHARED_P(ary)) {
-	if (new_len > RARRAY_EMBED_LEN_MAX) {
-	    VALUE shared = ARY_SHARED(ary);
-	    if (ARY_SHARED_OCCUPIED(shared)) {
-		if (RARRAY_CONST_PTR(ary) - RARRAY_CONST_PTR(shared) + new_len <= RARRAY_LEN(shared)) {
-		    rb_ary_modify_check(ary);
-		}
-		else {
-		    /* if array is shared, then it is likely it participate in push/shift pattern */
-		    rb_ary_modify(ary);
-		    capa = ARY_CAPA(ary);
-		    if (new_len > capa - (capa >> 6)) {
-			ary_double_capa(ary, new_len);
-		    }
-		}
-		return;
-	    }
-	}
+        if (new_len > ary_embed_capa(ary)) {
+            VALUE shared_root = ARY_SHARED_ROOT(ary);
+            if (ARY_SHARED_ROOT_OCCUPIED(shared_root)) {
+                if (ARY_HEAP_PTR(ary) - RARRAY_CONST_PTR_TRANSIENT(shared_root) + new_len <= RARRAY_LEN(shared_root)) {
+                    rb_ary_modify_check(ary);
+
+                    ary_verify(ary);
+                    ary_verify(shared_root);
+                    return shared_root;
+                }
+                else {
+                    /* if array is shared, then it is likely it participate in push/shift pattern */
+                    rb_ary_modify(ary);
+                    capa = ARY_CAPA(ary);
+                    if (new_len > capa - (capa >> 6)) {
+                        ary_double_capa(ary, new_len);
+                    }
+                    ary_verify(ary);
+                    return ary;
+                }
+            }
+        }
+        ary_verify(ary);
+        rb_ary_modify(ary);
+    }
+    else {
+        rb_ary_modify_check(ary);
     }
-    rb_ary_modify(ary);
     capa = ARY_CAPA(ary);
     if (new_len > capa) {
-	ary_double_capa(ary, new_len);
+        ary_double_capa(ary, new_len);
     }
+
+    ary_verify(ary);
+    return ary;
 }
 
 /*
  *  call-seq:
- *      ary.freeze -> ary
+ *    array.freeze -> self
  *
- *  Calls Object#freeze on +ary+ to prevent any further
- *  modification. A RuntimeError will be raised if a modification
- *  attempt is made.
+ *  Freezes +self+; returns +self+:
  *
+ *    a = []
+ *    a.frozen? # => false
+ *    a.freeze
+ *    a.frozen? # => true
+ *
+ *  An attempt to modify a frozen \Array raises FrozenError.
  */
 
 VALUE
@@ -394,21 +772,6 @@ rb_ary_freeze(VALUE ary)
     return rb_obj_freeze(ary);
 }
 
-/*
- *  call-seq:
- *     ary.frozen?  -> true or false
- *
- *  Return +true+ if this array is frozen (or temporarily frozen
- *  while being sorted). See also Object#frozen?
- */
-
-static VALUE
-rb_ary_frozen_p(VALUE ary)
-{
-    if (OBJ_FROZEN(ary)) return Qtrue;
-    return Qfalse;
-}
-
 /* This can be used to take a snapshot of an array (with
    e.g. rb_ary_replace) and check later whether the array has been
    modified from the snapshot.  The snapshot is cheap, though if
@@ -420,18 +783,25 @@ VALUE
 rb_ary_shared_with_p(VALUE ary1, VALUE ary2)
 {
     if (!ARY_EMBED_P(ary1) && ARY_SHARED_P(ary1) &&
-	!ARY_EMBED_P(ary2) && ARY_SHARED_P(ary2) &&
-	RARRAY(ary1)->as.heap.aux.shared == RARRAY(ary2)->as.heap.aux.shared &&
-	RARRAY(ary1)->as.heap.len == RARRAY(ary2)->as.heap.len) {
-	return Qtrue;
+            !ARY_EMBED_P(ary2) && ARY_SHARED_P(ary2) &&
+            ARY_SHARED_ROOT(ary1) == ARY_SHARED_ROOT(ary2) &&
+            ARY_HEAP_LEN(ary1) == ARY_HEAP_LEN(ary2)) {
+        return Qtrue;
     }
     return Qfalse;
 }
 
 static VALUE
-ary_alloc(VALUE klass)
+ary_alloc_embed(VALUE klass, long capa)
 {
-    NEWOBJ_OF(ary, struct RArray, klass, T_ARRAY | RARRAY_EMBED_FLAG | (RGENGC_WB_PROTECTED_ARRAY ? FL_WB_PROTECTED : 0));
+    size_t size = ary_embed_size(capa);
+    assert(rb_gc_size_allocatable_p(size));
+#if !USE_RVARGC
+    assert(size <= sizeof(struct RArray));
+#endif
+    RVARGC_NEWOBJ_OF(ary, struct RArray, klass,
+                     T_ARRAY | RARRAY_EMBED_FLAG | (RGENGC_WB_PROTECTED_ARRAY ? FL_WB_PROTECTED : 0),
+                     size);
     /* Created array is:
      *   FL_SET_EMBED((VALUE)ary);
      *   ARY_SET_EMBED_LEN((VALUE)ary, 0);
@@ -440,13 +810,19 @@ ary_alloc(VALUE klass)
 }
 
 static VALUE
-empty_ary_alloc(VALUE klass)
+ary_alloc_heap(VALUE klass)
 {
-    if (RUBY_DTRACE_ARRAY_CREATE_ENABLED()) {
-	RUBY_DTRACE_ARRAY_CREATE(0, rb_sourcefile(), rb_sourceline());
-    }
+    RVARGC_NEWOBJ_OF(ary, struct RArray, klass,
+                     T_ARRAY | (RGENGC_WB_PROTECTED_ARRAY ? FL_WB_PROTECTED : 0),
+                     sizeof(struct RArray));
+    return (VALUE)ary;
+}
 
-    return ary_alloc(klass);
+static VALUE
+empty_ary_alloc(VALUE klass)
+{
+    RUBY_DTRACE_CREATE_HOOK(ARRAY, 0);
+    return ary_alloc_embed(klass, 0);
 }
 
 static VALUE
@@ -455,27 +831,26 @@ ary_new(VALUE klass, long capa)
     VALUE ary,*ptr;
 
     if (capa < 0) {
-	rb_raise(rb_eArgError, "negative array size (or size too big)");
+        rb_raise(rb_eArgError, "negative array size (or size too big)");
     }
     if (capa > ARY_MAX_SIZE) {
-	rb_raise(rb_eArgError, "array size too big");
+        rb_raise(rb_eArgError, "array size too big");
     }
 
-    if (RUBY_DTRACE_ARRAY_CREATE_ENABLED()) {
-	RUBY_DTRACE_ARRAY_CREATE(capa, rb_sourcefile(), rb_sourceline());
+    RUBY_DTRACE_CREATE_HOOK(ARRAY, capa);
+
+    if (ary_embeddable_p(capa)) {
+        ary = ary_alloc_embed(klass, capa);
     }
+    else {
+        ary = ary_alloc_heap(klass);
+        ARY_SET_CAPA(ary, capa);
+        assert(!ARY_EMBED_P(ary));
 
-    if (capa > RARRAY_EMBED_LEN_MAX) {
-	ptr = ALLOC_N(VALUE, capa);
-	ary = ary_alloc(klass);
-        FL_UNSET_EMBED(ary);
+        ptr = ary_heap_alloc(ary, capa);
         ARY_SET_PTR(ary, ptr);
-        ARY_SET_CAPA(ary, capa);
         ARY_SET_HEAP_LEN(ary, 0);
     }
-    else {
-	ary = ary_alloc(klass);
-    }
 
     return ary;
 }
@@ -489,11 +864,11 @@ rb_ary_new_capa(long capa)
 VALUE
 rb_ary_new(void)
 {
-    return rb_ary_new2(RARRAY_EMBED_LEN_MAX);
+    return rb_ary_new_capa(0);
 }
 
 VALUE
-rb_ary_new_from_args(long n, ...)
+(rb_ary_new_from_args)(long n, ...)
 {
     va_list ar;
     VALUE ary;
@@ -503,7 +878,7 @@ rb_ary_new_from_args(long n, ...)
 
     va_start(ar, n);
     for (i=0; i<n; i++) {
-	RARRAY_ASET(ary, i, va_arg(ar, VALUE));
+        ARY_SET(ary, i, va_arg(ar, VALUE));
     }
     va_end(ar);
 
@@ -511,31 +886,141 @@ rb_ary_new_from_args(long n, ...)
     return ary;
 }
 
+MJIT_FUNC_EXPORTED VALUE
+rb_ary_tmp_new_from_values(VALUE klass, long n, const VALUE *elts)
+{
+    VALUE ary;
+
+    ary = ary_new(klass, n);
+    if (n > 0 && elts) {
+        ary_memcpy(ary, 0, n, elts);
+        ARY_SET_LEN(ary, n);
+    }
+
+    return ary;
+}
+
 VALUE
 rb_ary_new_from_values(long n, const VALUE *elts)
 {
+    return rb_ary_tmp_new_from_values(rb_cArray, n, elts);
+}
+
+static VALUE
+ec_ary_alloc_embed(rb_execution_context_t *ec, VALUE klass, long capa)
+{
+    size_t size = ary_embed_size(capa);
+    assert(rb_gc_size_allocatable_p(size));
+#if !USE_RVARGC
+    assert(size <= sizeof(struct RArray));
+#endif
+    RB_RVARGC_EC_NEWOBJ_OF(ec, ary, struct RArray, klass,
+                           T_ARRAY | RARRAY_EMBED_FLAG | (RGENGC_WB_PROTECTED_ARRAY ? FL_WB_PROTECTED : 0),
+                           size);
+    /* Created array is:
+     *   FL_SET_EMBED((VALUE)ary);
+     *   ARY_SET_EMBED_LEN((VALUE)ary, 0);
+     */
+    return (VALUE)ary;
+}
+
+static VALUE
+ec_ary_alloc_heap(rb_execution_context_t *ec, VALUE klass)
+{
+    RB_RVARGC_EC_NEWOBJ_OF(ec, ary, struct RArray, klass,
+                           T_ARRAY | (RGENGC_WB_PROTECTED_ARRAY ? FL_WB_PROTECTED : 0),
+                           sizeof(struct RArray));
+    return (VALUE)ary;
+}
+
+static VALUE
+ec_ary_new(rb_execution_context_t *ec, VALUE klass, long capa)
+{
+    VALUE ary,*ptr;
+
+    if (capa < 0) {
+        rb_raise(rb_eArgError, "negative array size (or size too big)");
+    }
+    if (capa > ARY_MAX_SIZE) {
+        rb_raise(rb_eArgError, "array size too big");
+    }
+
+    RUBY_DTRACE_CREATE_HOOK(ARRAY, capa);
+
+    if (ary_embeddable_p(capa)) {
+        ary = ec_ary_alloc_embed(ec, klass, capa);
+    }
+    else {
+        ary = ec_ary_alloc_heap(ec, klass);
+        ARY_SET_CAPA(ary, capa);
+        assert(!ARY_EMBED_P(ary));
+
+        ptr = ary_heap_alloc(ary, capa);
+        ARY_SET_PTR(ary, ptr);
+        ARY_SET_HEAP_LEN(ary, 0);
+    }
+
+    return ary;
+}
+
+VALUE
+rb_ec_ary_new_from_values(rb_execution_context_t *ec, long n, const VALUE *elts)
+{
     VALUE ary;
 
-    ary = rb_ary_new2(n);
+    ary = ec_ary_new(ec, rb_cArray, n);
     if (n > 0 && elts) {
-	ary_memcpy(ary, 0, n, elts);
-	ARY_SET_LEN(ary, n);
+        ary_memcpy(ary, 0, n, elts);
+        ARY_SET_LEN(ary, n);
     }
 
     return ary;
 }
 
 VALUE
-rb_ary_tmp_new(long capa)
+rb_ary_hidden_new(long capa)
 {
-    return ary_new(0, capa);
+    VALUE ary = ary_new(0, capa);
+    rb_ary_transient_heap_evacuate(ary, TRUE);
+    return ary;
+}
+
+VALUE
+rb_ary_hidden_new_fill(long capa)
+{
+    VALUE ary = rb_ary_hidden_new(capa);
+    ary_memfill(ary, 0, capa, Qnil);
+    ARY_SET_LEN(ary, capa);
+    return ary;
 }
 
 void
 rb_ary_free(VALUE ary)
 {
     if (ARY_OWNS_HEAP_P(ary)) {
-	ruby_sized_xfree((void *)ARY_HEAP_PTR(ary), ARY_HEAP_SIZE(ary));
+        if (USE_DEBUG_COUNTER &&
+            !ARY_SHARED_ROOT_P(ary) &&
+            ARY_HEAP_CAPA(ary) > RARRAY_LEN(ary)) {
+            RB_DEBUG_COUNTER_INC(obj_ary_extracapa);
+        }
+
+        if (RARRAY_TRANSIENT_P(ary)) {
+            RB_DEBUG_COUNTER_INC(obj_ary_transient);
+        }
+        else {
+            RB_DEBUG_COUNTER_INC(obj_ary_ptr);
+            ary_heap_free(ary);
+        }
+    }
+    else {
+        RB_DEBUG_COUNTER_INC(obj_ary_embed);
+    }
+
+    if (ARY_SHARED_P(ary)) {
+        RB_DEBUG_COUNTER_INC(obj_ary_shared);
+    }
+    if (ARY_SHARED_ROOT_P(ary) && ARY_SHARED_ROOT_OCCUPIED(ary)) {
+        RB_DEBUG_COUNTER_INC(obj_ary_shared_root_occupied);
     }
 }
 
@@ -543,51 +1028,69 @@ RUBY_FUNC_EXPORTED size_t
 rb_ary_memsize(VALUE ary)
 {
     if (ARY_OWNS_HEAP_P(ary)) {
-	return RARRAY(ary)->as.heap.aux.capa * sizeof(VALUE);
+        return ARY_CAPA(ary) * sizeof(VALUE);
     }
     else {
-	return 0;
+        return 0;
     }
 }
 
-static inline void
-ary_discard(VALUE ary)
-{
-    rb_ary_free(ary);
-    RBASIC(ary)->flags |= RARRAY_EMBED_FLAG;
-    RBASIC(ary)->flags &= ~RARRAY_EMBED_LEN_MASK;
-}
-
 static VALUE
 ary_make_shared(VALUE ary)
 {
-    assert(!ARY_EMBED_P(ary));
+    assert(USE_RVARGC || !ARY_EMBED_P(ary));
+    ary_verify(ary);
+
     if (ARY_SHARED_P(ary)) {
-	return ARY_SHARED(ary);
+        return ARY_SHARED_ROOT(ary);
     }
     else if (ARY_SHARED_ROOT_P(ary)) {
-	return ary;
+        return ary;
     }
     else if (OBJ_FROZEN(ary)) {
-	ary_shrink_capa(ary);
-	FL_SET_SHARED_ROOT(ary);
-	ARY_SET_SHARED_NUM(ary, 1);
-	return ary;
+        if (!ARY_EMBED_P(ary)) {
+            rb_ary_transient_heap_evacuate(ary, TRUE);
+            ary_shrink_capa(ary);
+        }
+        return ary;
     }
     else {
-	long capa = ARY_CAPA(ary), len = RARRAY_LEN(ary);
-	NEWOBJ_OF(shared, struct RArray, 0, T_ARRAY); /* keep shared ary as non-WB-protected */
-        FL_UNSET_EMBED(shared);
+        rb_ary_transient_heap_evacuate(ary, TRUE);
+
+        long capa = ARY_CAPA(ary);
+        long len = RARRAY_LEN(ary);
+
+        /* Shared roots cannot be embedded because the reference count
+         * (refcnt) is stored in as.heap.aux.capa. */
+        VALUE shared = ary_alloc_heap(0);
+        FL_SET_SHARED_ROOT(shared);
+
+        if (ARY_EMBED_P(ary)) {
+            /* Cannot use ary_heap_alloc because we don't want to allocate
+             * on the transient heap. */
+            VALUE *ptr = ALLOC_N(VALUE, capa);
+            ARY_SET_PTR(shared, ptr);
+            ary_memcpy(shared, 0, len, RARRAY_PTR(ary));
+
+            FL_UNSET_EMBED(ary);
+            ARY_SET_HEAP_LEN(ary, len);
+            ARY_SET_PTR(ary, ptr);
+        }
+        else {
+            ARY_SET_PTR(shared, RARRAY_PTR(ary));
+        }
+
+        ARY_SET_LEN(shared, capa);
+        ary_mem_clear(shared, len, capa - len);
+        ARY_SET_SHARED_ROOT_REFCNT(shared, 1);
+        FL_SET_SHARED(ary);
+        RB_DEBUG_COUNTER_INC(obj_ary_shared_create);
+        ARY_SET_SHARED(ary, shared);
 
-	ARY_SET_LEN((VALUE)shared, capa);
-	ARY_SET_PTR((VALUE)shared, RARRAY_CONST_PTR(ary));
-	ary_mem_clear((VALUE)shared, len, capa - len);
-	FL_SET_SHARED_ROOT(shared);
-	ARY_SET_SHARED_NUM((VALUE)shared, 1);
-	FL_SET_SHARED(ary);
-	ARY_SET_SHARED(ary, (VALUE)shared);
-	OBJ_FREEZE(shared);
-	return (VALUE)shared;
+        ary_verify(shared);
+        ary_verify(ary);
+
+        return shared;
     }
 }
 
@@ -596,9 +1099,11 @@ ary_make_substitution(VALUE ary)
 {
     long len = RARRAY_LEN(ary);
 
-    if (len <= RARRAY_EMBED_LEN_MAX) {
-	VALUE subst = rb_ary_new2(len);
-	ary_memcpy(subst, 0, len, RARRAY_CONST_PTR(ary));
+    if (ary_embeddable_p(len)) {
+        VALUE subst = rb_ary_new_capa(len);
+        assert(ARY_EMBED_P(subst));
+
+        ary_memcpy(subst, 0, len, RARRAY_CONST_PTR_TRANSIENT(ary));
         ARY_SET_EMBED_LEN(subst, len);
         return subst;
     }
@@ -613,35 +1118,43 @@ rb_assoc_new(VALUE car, VALUE cdr)
     return rb_ary_new3(2, car, cdr);
 }
 
-static VALUE
-to_ary(VALUE ary)
+VALUE
+rb_to_array_type(VALUE ary)
 {
-    return rb_convert_type(ary, T_ARRAY, "Array", "to_ary");
+    return rb_convert_type_with_id(ary, T_ARRAY, "Array", idTo_ary);
 }
+#define to_ary rb_to_array_type
 
 VALUE
 rb_check_array_type(VALUE ary)
 {
-    return rb_check_convert_type(ary, T_ARRAY, "Array", "to_ary");
+    return rb_check_convert_type_with_id(ary, T_ARRAY, "Array", idTo_ary);
+}
+
+MJIT_FUNC_EXPORTED VALUE
+rb_check_to_array(VALUE ary)
+{
+    return rb_check_convert_type_with_id(ary, T_ARRAY, "Array", idTo_a);
+}
+
+VALUE
+rb_to_array(VALUE ary)
+{
+    return rb_convert_type_with_id(ary, T_ARRAY, "Array", idTo_a);
 }
 
 /*
  *  call-seq:
- *     Array.try_convert(obj) -> array or nil
+ *    Array.try_convert(object) -> object, new_array, or nil
  *
- *  Tries to convert +obj+ into an array, using +to_ary+ method.  Returns the
- *  converted array or +nil+ if +obj+ cannot be converted for any reason.
- *  This method can be used to check if an argument is an array.
+ *  If +object+ is an \Array object, returns +object+.
  *
- *     Array.try_convert([1])   #=> [1]
- *     Array.try_convert("1")   #=> nil
+ *  Otherwise if +object+ responds to <tt>:to_ary</tt>,
+ *  calls <tt>object.to_ary</tt> and returns the result.
  *
- *     if tmp = Array.try_convert(arg)
- *       # the argument is an array
- *     elsif tmp = String.try_convert(arg)
- *       # the argument is a string
- *     end
+ *  Returns +nil+ if +object+ does not respond to <tt>:to_ary</tt>
  *
+ *  Raises an exception unless <tt>object.to_ary</tt> returns an \Array object.
  */
 
 static VALUE
@@ -650,60 +1163,76 @@ rb_ary_s_try_convert(VALUE dummy, VALUE ary)
     return rb_check_array_type(ary);
 }
 
+/* :nodoc: */
+static VALUE
+rb_ary_s_new(int argc, VALUE *argv, VALUE klass)
+{
+    VALUE ary;
+
+    if (klass == rb_cArray) {
+        long size = 0;
+        if (argc > 0 && FIXNUM_P(argv[0])) {
+            size = FIX2LONG(argv[0]);
+            if (size < 0) size = 0;
+        }
+
+        ary = ary_new(klass, size);
+
+        rb_obj_call_init_kw(ary, argc, argv, RB_PASS_CALLED_KEYWORDS);
+    }
+    else {
+        ary = rb_class_new_instance_pass_kw(argc, argv, klass);
+    }
+
+    return ary;
+}
+
 /*
  *  call-seq:
- *     Array.new(size=0, obj=nil)
- *     Array.new(array)
- *     Array.new(size) {|index| block }
- *
- *  Returns a new array.
- *
- *  In the first form, if no arguments are sent, the new array will be empty.
- *  When a +size+ and an optional +obj+ are sent, an array is created with
- *  +size+ copies of +obj+.  Take notice that all elements will reference the
- *  same object +obj+.
- *
- *  The second form creates a copy of the array passed as a parameter (the
- *  array is generated by calling to_ary on the parameter).
- *
- *    first_array = ["Matz", "Guido"]
- *
- *    second_array = Array.new(first_array) #=> ["Matz", "Guido"]
+ *    Array.new -> new_empty_array
+ *    Array.new(array) -> new_array
+ *    Array.new(size) -> new_array
+ *    Array.new(size, default_value) -> new_array
+ *    Array.new(size) {|index| ... } -> new_array
  *
- *    first_array.equal? second_array       #=> false
+ *  Returns a new \Array.
  *
- *  In the last form, an array of the given size is created.  Each element in
- *  this array is created by passing the element's index to the given block
- *  and storing the return value.
+ *  With no block and no arguments, returns a new empty \Array object.
  *
- *    Array.new(3){ |index| index ** 2 }
- *    # => [0, 1, 4]
+ *  With no block and a single \Array argument +array+,
+ *  returns a new \Array formed from +array+:
  *
- *  == Common gotchas
+ *    a = Array.new([:foo, 'bar', 2])
+ *    a.class # => Array
+ *    a # => [:foo, "bar", 2]
  *
- *  When sending the second parameter, the same object will be used as the
- *  value for all the array elements:
+ *  With no block and a single \Integer argument +size+,
+ *  returns a new \Array of the given size
+ *  whose elements are all +nil+:
  *
- *     a = Array.new(2, Hash.new)
- *     # => [{}, {}]
+ *    a = Array.new(3)
+ *    a # => [nil, nil, nil]
  *
- *     a[0]['cat'] = 'feline'
- *     a # => [{"cat"=>"feline"}, {"cat"=>"feline"}]
+ *  With no block and arguments +size+ and +default_value+,
+ *  returns an \Array of the given size;
+ *  each element is that same +default_value+:
  *
- *     a[1]['cat'] = 'Felix'
- *     a # => [{"cat"=>"Felix"}, {"cat"=>"Felix"}]
+ *    a = Array.new(3, 'x')
+ *    a # => ['x', 'x', 'x']
  *
- *  Since all the Array elements store the same hash, changes to one of them
- *  will affect them all.
+ *  With a block and argument +size+,
+ *  returns an \Array of the given size;
+ *  the block is called with each successive integer +index+;
+ *  the element for that +index+ is the return value from the block:
  *
- *  If multiple copies are what you want, you should use the block
- *  version which uses the result of that block each time an element
- *  of the array needs to be initialized:
+ *    a = Array.new(3) {|index| "Element #{index}" }
+ *    a # => ["Element 0", "Element 1", "Element 2"]
  *
- *     a = Array.new(2) { Hash.new }
- *     a[0]['cat'] = 'feline'
- *     a # => [{"cat"=>"feline"}, {}]
+ *  Raises ArgumentError if +size+ is negative.
  *
+ *  With a block and no argument,
+ *  or a single argument +0+,
+ *  ignores the block and returns a new empty \Array.
  */
 
 static VALUE
@@ -714,49 +1243,48 @@ rb_ary_initialize(int argc, VALUE *argv, VALUE ary)
 
     rb_ary_modify(ary);
     if (argc == 0) {
-	if (ARY_OWNS_HEAP_P(ary) && RARRAY_CONST_PTR(ary) != 0) {
-	    ruby_sized_xfree((void *)RARRAY_CONST_PTR(ary), ARY_HEAP_SIZE(ary));
-	}
-        rb_ary_unshare_safe(ary);
-        FL_SET_EMBED(ary);
-	ARY_SET_EMBED_LEN(ary, 0);
-	if (rb_block_given_p()) {
-	    rb_warning("given block not used");
-	}
-	return ary;
+        rb_ary_reset(ary);
+        assert(ARY_EMBED_P(ary));
+        assert(ARY_EMBED_LEN(ary) == 0);
+        if (rb_block_given_p()) {
+            rb_warning("given block not used");
+        }
+        return ary;
     }
     rb_scan_args(argc, argv, "02", &size, &val);
     if (argc == 1 && !FIXNUM_P(size)) {
-	val = rb_check_array_type(size);
-	if (!NIL_P(val)) {
-	    rb_ary_replace(ary, val);
-	    return ary;
-	}
+        val = rb_check_array_type(size);
+        if (!NIL_P(val)) {
+            rb_ary_replace(ary, val);
+            return ary;
+        }
     }
 
     len = NUM2LONG(size);
+    /* NUM2LONG() may call size.to_int, ary can be frozen, modified, etc */
     if (len < 0) {
-	rb_raise(rb_eArgError, "negative array size");
+        rb_raise(rb_eArgError, "negative array size");
     }
     if (len > ARY_MAX_SIZE) {
-	rb_raise(rb_eArgError, "array size too big");
+        rb_raise(rb_eArgError, "array size too big");
     }
+    /* recheck after argument conversion */
     rb_ary_modify(ary);
     ary_resize_capa(ary, len);
     if (rb_block_given_p()) {
-	long i;
+        long i;
 
-	if (argc == 2) {
-	    rb_warn("block supersedes default value argument");
-	}
-	for (i=0; i<len; i++) {
-	    rb_ary_store(ary, i, rb_yield(LONG2NUM(i)));
-	    ARY_SET_LEN(ary, i + 1);
-	}
+        if (argc == 2) {
+            rb_warn("block supersedes default value argument");
+        }
+        for (i=0; i<len; i++) {
+            rb_ary_store(ary, i, rb_yield(LONG2NUM(i)));
+            ARY_SET_LEN(ary, i + 1);
+        }
     }
     else {
-	ary_memfill(ary, 0, len, val);
-	ARY_SET_LEN(ary, len);
+        ary_memfill(ary, 0, len, val);
+        ARY_SET_LEN(ary, len);
     }
     return ary;
 }
@@ -764,7 +1292,7 @@ rb_ary_initialize(int argc, VALUE *argv, VALUE ary)
 /*
  * Returns a new array populated with the given objects.
  *
- *   Array.[]( 1, 'a', /^A/ ) # => [1, "a", /^A/]
+ *   Array.[]( 1, 'a', /^A/)  # => [1, "a", /^A/]
  *   Array[ 1, 'a', /^A/ ]    # => [1, "a", /^A/]
  *   [ 1, 'a', /^A/ ]         # => [1, "a", /^A/]
  */
@@ -787,28 +1315,28 @@ rb_ary_store(VALUE ary, long idx, VALUE val)
     long len = RARRAY_LEN(ary);
 
     if (idx < 0) {
-	idx += len;
-	if (idx < 0) {
-	    rb_raise(rb_eIndexError, "index %ld too small for array; minimum: %ld",
-		     idx - len, -len);
-	}
+        idx += len;
+        if (idx < 0) {
+            rb_raise(rb_eIndexError, "index %ld too small for array; minimum: %ld",
+                     idx - len, -len);
+        }
     }
     else if (idx >= ARY_MAX_SIZE) {
-	rb_raise(rb_eIndexError, "index %ld too big", idx);
+        rb_raise(rb_eIndexError, "index %ld too big", idx);
     }
 
     rb_ary_modify(ary);
     if (idx >= ARY_CAPA(ary)) {
-	ary_double_capa(ary, idx);
+        ary_double_capa(ary, idx);
     }
     if (idx > len) {
-	ary_mem_clear(ary, len, idx - len + 1);
+        ary_mem_clear(ary, len, idx - len + 1);
     }
 
     if (idx >= len) {
-	ARY_SET_LEN(ary, idx + 1);
+        ARY_SET_LEN(ary, idx + 1);
     }
-    RARRAY_ASET(ary, idx, val);
+    ARY_SET(ary, idx, val);
 }
 
 static VALUE
@@ -818,31 +1346,87 @@ ary_make_partial(VALUE ary, VALUE klass, long offset, long len)
     assert(len >= 0);
     assert(offset+len <= RARRAY_LEN(ary));
 
-    if (len <= RARRAY_EMBED_LEN_MAX) {
-        VALUE result = ary_alloc(klass);
-	ary_memcpy(result, 0, len, RARRAY_CONST_PTR(ary) + offset);
+    const size_t rarray_embed_capa_max = (sizeof(struct RArray) - offsetof(struct RArray, as.ary)) / sizeof(VALUE);
+
+    if ((size_t)len <= rarray_embed_capa_max && ary_embeddable_p(len)) {
+        VALUE result = ary_alloc_embed(klass, len);
+        ary_memcpy(result, 0, len, RARRAY_CONST_PTR_TRANSIENT(ary) + offset);
         ARY_SET_EMBED_LEN(result, len);
         return result;
     }
     else {
-        VALUE shared, result = ary_alloc(klass);
-        FL_UNSET_EMBED(result);
+        VALUE shared = ary_make_shared(ary);
 
-        shared = ary_make_shared(ary);
-        ARY_SET_PTR(result, RARRAY_CONST_PTR(ary));
+        VALUE result = ary_alloc_heap(klass);
+        assert(!ARY_EMBED_P(result));
+
+        ARY_SET_PTR(result, RARRAY_CONST_PTR_TRANSIENT(ary));
         ARY_SET_LEN(result, RARRAY_LEN(ary));
         rb_ary_set_shared(result, shared);
 
         ARY_INCREASE_PTR(result, offset);
         ARY_SET_LEN(result, len);
+
+        ary_verify(shared);
+        ary_verify(result);
+        return result;
+    }
+}
+
+static VALUE
+ary_make_partial_step(VALUE ary, VALUE klass, long offset, long len, long step)
+{
+    assert(offset >= 0);
+    assert(len >= 0);
+    assert(offset+len <= RARRAY_LEN(ary));
+    assert(step != 0);
+
+    const VALUE *values = RARRAY_CONST_PTR_TRANSIENT(ary);
+    const long orig_len = len;
+
+    if (step > 0 && step >= len) {
+        VALUE result = ary_new(klass, 1);
+        VALUE *ptr = (VALUE *)ARY_EMBED_PTR(result);
+        RB_OBJ_WRITE(result, ptr, values[offset]);
+        ARY_SET_EMBED_LEN(result, 1);
         return result;
     }
+    else if (step < 0 && step < -len) {
+        step = -len;
+    }
+
+    long ustep = (step < 0) ? -step : step;
+    len = roomof(len, ustep);
+
+    long i;
+    long j = offset + ((step > 0) ? 0 : (orig_len - 1));
+
+    VALUE result = ary_new(klass, len);
+    if (ARY_EMBED_P(result)) {
+        VALUE *ptr = (VALUE *)ARY_EMBED_PTR(result);
+        for (i = 0; i < len; ++i) {
+            RB_OBJ_WRITE(result, ptr+i, values[j]);
+            j += step;
+        }
+        ARY_SET_EMBED_LEN(result, len);
+    }
+    else {
+        RARRAY_PTR_USE_TRANSIENT(result, ptr, {
+            for (i = 0; i < len; ++i) {
+                RB_OBJ_WRITE(result, ptr+i, values[j]);
+                j += step;
+            }
+        });
+        ARY_SET_LEN(result, len);
+    }
+
+    return result;
 }
 
 static VALUE
 ary_make_shared_copy(VALUE ary)
 {
-    return ary_make_partial(ary, rb_obj_class(ary), 0, RARRAY_LEN(ary));
+    return ary_make_partial(ary, rb_cArray, 0, RARRAY_LEN(ary));
 }
 
 enum ary_take_pos_flags
@@ -852,90 +1436,92 @@ enum ary_take_pos_flags
 };
 
 static VALUE
-ary_take_first_or_last(int argc, VALUE *argv, VALUE ary, enum ary_take_pos_flags last)
+ary_take_first_or_last(int argc, const VALUE *argv, VALUE ary, enum ary_take_pos_flags last)
 {
-    VALUE nv;
     long n;
     long len;
     long offset = 0;
 
-    rb_scan_args(argc, argv, "1", &nv);
-    n = NUM2LONG(nv);
+    argc = rb_check_arity(argc, 0, 1);
+    /* the case optional argument is omitted should be handled in
+     * callers of this function.  if another arity case is added,
+     * this arity check needs to rewrite. */
+    RUBY_ASSERT_ALWAYS(argc == 1);
+
+    n = NUM2LONG(argv[0]);
     len = RARRAY_LEN(ary);
     if (n > len) {
-	n = len;
+        n = len;
     }
     else if (n < 0) {
-	rb_raise(rb_eArgError, "negative array size");
+        rb_raise(rb_eArgError, "negative array size");
     }
     if (last) {
-	offset = len - n;
+        offset = len - n;
     }
     return ary_make_partial(ary, rb_cArray, offset, n);
 }
 
 /*
  *  call-seq:
- *     ary << obj            -> ary
+ *    array << object -> self
+ *
+ *  Appends +object+ to +self+; returns +self+:
  *
- *  Append---Pushes the given object on to the end of this array. This
- *  expression returns the array itself, so several appends
- *  may be chained together.
+ *    a = [:foo, 'bar', 2]
+ *    a << :baz # => [:foo, "bar", 2, :baz]
  *
- *     [ 1, 2 ] << "c" << "d" << [ 3, 4 ]
- *             #=>  [ 1, 2, "c", "d", [ 3, 4 ] ]
+ *  Appends +object+ as one element, even if it is another \Array:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a1 = a << [3, 4]
+ *    a1 # => [:foo, "bar", 2, [3, 4]]
  *
  */
 
 VALUE
 rb_ary_push(VALUE ary, VALUE item)
 {
-    long idx = RARRAY_LEN(ary);
-
-    ary_ensure_room_for_push(ary, 1);
-    RARRAY_ASET(ary, idx, item);
-    ARY_SET_LEN(ary, idx + 1);
-    return ary;
-}
-
-static VALUE
-rb_ary_push_1(VALUE ary, VALUE item)
-{
-    long idx = RARRAY_LEN(ary);
-
-    if (idx >= ARY_CAPA(ary)) {
-	ary_double_capa(ary, idx);
-    }
-    RARRAY_ASET(ary, idx, item);
+    long idx = RARRAY_LEN((ary_verify(ary), ary));
+    VALUE target_ary = ary_ensure_room_for_push(ary, 1);
+    RARRAY_PTR_USE_TRANSIENT(ary, ptr, {
+        RB_OBJ_WRITE(target_ary, &ptr[idx], item);
+    });
     ARY_SET_LEN(ary, idx + 1);
+    ary_verify(ary);
     return ary;
 }
 
 VALUE
-rb_ary_cat(VALUE ary, const VALUE *ptr, long len)
+rb_ary_cat(VALUE ary, const VALUE *argv, long len)
 {
     long oldlen = RARRAY_LEN(ary);
-
-    ary_ensure_room_for_push(ary, len);
-    ary_memcpy(ary, oldlen, len, ptr);
+    VALUE target_ary = ary_ensure_room_for_push(ary, len);
+    ary_memcpy0(ary, oldlen, len, argv, target_ary);
     ARY_SET_LEN(ary, oldlen + len);
     return ary;
 }
 
 /*
  *  call-seq:
- *     ary.push(obj, ... )   -> ary
- *
- *  Append --- Pushes the given object(s) on to the end of this array. This
- *  expression returns the array itself, so several appends
- *  may be chained together. See also Array#pop for the opposite
- *  effect.
- *
- *     a = [ "a", "b", "c" ]
- *     a.push("d", "e", "f")
- *             #=> ["a", "b", "c", "d", "e", "f"]
- *     [1, 2, 3,].push(4).push(5)
- *             #=> [1, 2, 3, 4, 5]
+ *    array.push(*objects) -> self
+ *
+ *  Appends trailing elements.
+ *
+ *  Appends each argument in +objects+ to +self+;  returns +self+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.push(:baz, :bat) # => [:foo, "bar", 2, :baz, :bat]
+ *
+ *  Appends each argument as one element, even if it is another \Array:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a1 = a.push([:baz, :bat], [:bam, :bad])
+ *    a1 # => [:foo, "bar", 2, [:baz, :bat], [:bam, :bad]]
+ *
+ *  Array#append is an alias for Array#push.
+ *
+ *  Related: #pop, #shift, #unshift.
  */
 
 static VALUE
@@ -952,32 +1538,46 @@ rb_ary_pop(VALUE ary)
     n = RARRAY_LEN(ary);
     if (n == 0) return Qnil;
     if (ARY_OWNS_HEAP_P(ary) &&
-	n * 3 < ARY_CAPA(ary) &&
-	ARY_CAPA(ary) > ARY_DEFAULT_SIZE)
+        n * 3 < ARY_CAPA(ary) &&
+        ARY_CAPA(ary) > ARY_DEFAULT_SIZE)
     {
-	ary_resize_capa(ary, n * 2);
+        ary_resize_capa(ary, n * 2);
     }
     --n;
     ARY_SET_LEN(ary, n);
+    ary_verify(ary);
     return RARRAY_AREF(ary, n);
 }
 
 /*
  *  call-seq:
- *     ary.pop    -> obj or nil
- *     ary.pop(n) -> new_ary
+ *    array.pop -> object or nil
+ *    array.pop(n) -> new_array
+ *
+ *  Removes and returns trailing elements.
+ *
+ *  When no argument is given and +self+ is not empty,
+ *  removes and returns the last element:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.pop # => 2
+ *    a # => [:foo, "bar"]
+ *
+ *  Returns +nil+ if the array is empty.
  *
- *  Removes the last element from +self+ and returns it, or
- *  +nil+ if the array is empty.
+ *  When a non-negative \Integer argument +n+ is given and is in range,
  *
- *  If a number +n+ is given, returns an array of the last +n+ elements
- *  (or less) just like <code>array.slice!(-n, n)</code> does. See also
- *  Array#push for the opposite effect.
+ *  removes and returns the last +n+ elements in a new \Array:
+ *    a = [:foo, 'bar', 2]
+ *    a.pop(2) # => ["bar", 2]
  *
- *     a = [ "a", "b", "c", "d" ]
- *     a.pop     #=> "d"
- *     a.pop(2)  #=> ["b", "c"]
- *     a         #=> ["a"]
+ *  If +n+ is positive and out of range,
+ *  removes and returns all elements:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.pop(50) # => [:foo, "bar", 2]
+ *
+ *  Related: #push, #shift, #unshift.
  */
 
 static VALUE
@@ -986,12 +1586,13 @@ rb_ary_pop_m(int argc, VALUE *argv, VALUE ary)
     VALUE result;
 
     if (argc == 0) {
-	return rb_ary_pop(ary);
+        return rb_ary_pop(ary);
     }
 
     rb_ary_modify_check(ary);
     result = ary_take_first_or_last(argc, argv, ary, ARY_TAKE_LAST);
     ARY_INCREASE_LEN(ary, -RARRAY_LEN(result));
+    ary_verify(ary);
     return result;
 }
 
@@ -1001,52 +1602,49 @@ rb_ary_shift(VALUE ary)
     VALUE top;
     long len = RARRAY_LEN(ary);
 
-    rb_ary_modify_check(ary);
-    if (len == 0) return Qnil;
+    if (len == 0) {
+        rb_ary_modify_check(ary);
+        return Qnil;
+    }
+
     top = RARRAY_AREF(ary, 0);
-    if (!ARY_SHARED_P(ary)) {
-	if (len < ARY_DEFAULT_SIZE) {
-	    RARRAY_PTR_USE(ary, ptr, {
-		MEMMOVE(ptr, ptr+1, VALUE, len-1);
-	    }); /* WB: no new reference */
-            ARY_INCREASE_LEN(ary, -1);
-	    return top;
-	}
-        assert(!ARY_EMBED_P(ary)); /* ARY_EMBED_LEN_MAX < ARY_DEFAULT_SIZE */
-
-	RARRAY_ASET(ary, 0, Qnil);
-	ary_make_shared(ary);
-    }
-    else if (ARY_SHARED_OCCUPIED(ARY_SHARED(ary))) {
-	RARRAY_ASET(ary, 0, Qnil);
-    }
-    ARY_INCREASE_PTR(ary, 1);		/* shift ptr */
-    ARY_INCREASE_LEN(ary, -1);
+
+    rb_ary_behead(ary, 1);
 
     return top;
 }
 
 /*
  *  call-seq:
- *     ary.shift    -> obj or nil
- *     ary.shift(n) -> new_ary
+ *     array.shift -> object or nil
+ *     array.shift(n) -> new_array
+ *
+ *  Removes and returns leading elements.
+ *
+ *  When no argument is given, removes and returns the first element:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.shift # => :foo
+ *    a # => ['bar', 2]
+ *
+ *  Returns +nil+ if +self+ is empty.
  *
- *  Removes the first element of +self+ and returns it (shifting all
- *  other elements down by one). Returns +nil+ if the array
- *  is empty.
+ *  When positive \Integer argument +n+ is given, removes the first +n+ elements;
+ *  returns those elements in a new \Array:
  *
- *  If a number +n+ is given, returns an array of the first +n+ elements
- *  (or less) just like <code>array.slice!(0, n)</code> does. With +ary+
- *  containing only the remainder elements, not including what was shifted to
- *  +new_ary+. See also Array#unshift for the opposite effect.
+ *    a = [:foo, 'bar', 2]
+ *    a.shift(2) # => [:foo, 'bar']
+ *    a # => [2]
  *
- *     args = [ "-m", "-q", "filename" ]
- *     args.shift     #=> "-m"
- *     args           #=> ["-q", "filename"]
+ *  If +n+ is as large as or larger than <tt>self.length</tt>,
+ *  removes all elements; returns those elements in a new \Array:
  *
- *     args = [ "-m", "-q", "filename" ]
- *     args.shift(2)  #=> ["-m", "-q"]
- *     args           #=> ["filename"]
+ *    a = [:foo, 'bar', 2]
+ *    a.shift(3) # => [:foo, 'bar', 2]
+ *
+ *  If +n+ is zero, returns a new empty \Array; +self+ is unmodified.
+ *
+ *  Related: #push, #pop, #unshift.
  */
 
 static VALUE
@@ -1056,103 +1654,162 @@ rb_ary_shift_m(int argc, VALUE *argv, VALUE ary)
     long n;
 
     if (argc == 0) {
-	return rb_ary_shift(ary);
+        return rb_ary_shift(ary);
     }
 
     rb_ary_modify_check(ary);
     result = ary_take_first_or_last(argc, argv, ary, ARY_TAKE_FIRST);
     n = RARRAY_LEN(result);
-    if (ARY_SHARED_P(ary)) {
-	if (ARY_SHARED_OCCUPIED(ARY_SHARED(ary))) {
-	    ary_mem_clear(ary, 0, n);
-	}
-        ARY_INCREASE_PTR(ary, n);
+    rb_ary_behead(ary,n);
+
+    return result;
+}
+
+MJIT_FUNC_EXPORTED VALUE
+rb_ary_behead(VALUE ary, long n)
+{
+    if (n <= 0) {
+        return ary;
     }
-    else {
-	RARRAY_PTR_USE(ary, ptr, {
-	    MEMMOVE(ptr, ptr + n, VALUE, RARRAY_LEN(ary)-n);
-	}); /* WB: no new reference */
+
+    rb_ary_modify_check(ary);
+
+    if (!ARY_SHARED_P(ary)) {
+        if (ARY_EMBED_P(ary) || RARRAY_LEN(ary) < ARY_DEFAULT_SIZE) {
+            RARRAY_PTR_USE_TRANSIENT(ary, ptr, {
+                MEMMOVE(ptr, ptr + n, VALUE, RARRAY_LEN(ary) - n);
+            }); /* WB: no new reference */
+            ARY_INCREASE_LEN(ary, -n);
+            ary_verify(ary);
+            return ary;
+        }
+
+        ary_mem_clear(ary, 0, n);
+        ary_make_shared(ary);
     }
+    else if (ARY_SHARED_ROOT_OCCUPIED(ARY_SHARED_ROOT(ary))) {
+        ary_mem_clear(ary, 0, n);
+    }
+
+    ARY_INCREASE_PTR(ary, n);
     ARY_INCREASE_LEN(ary, -n);
+    ary_verify(ary);
 
-    return result;
+    return ary;
 }
 
-static void
-ary_ensure_room_for_unshift(VALUE ary, int argc)
+static VALUE
+make_room_for_unshift(VALUE ary, const VALUE *head, VALUE *sharedp, int argc, long capa, long len)
+{
+    if (head - sharedp < argc) {
+        long room = capa - len - argc;
+
+        room -= room >> 4;
+        MEMMOVE((VALUE *)sharedp + argc + room, head, VALUE, len);
+        head = sharedp + argc + room;
+    }
+    ARY_SET_PTR(ary, head - argc);
+    assert(ARY_SHARED_ROOT_OCCUPIED(ARY_SHARED_ROOT(ary)));
+
+    ary_verify(ary);
+    return ARY_SHARED_ROOT(ary);
+}
+
+static VALUE
+ary_modify_for_unshift(VALUE ary, int argc)
 {
     long len = RARRAY_LEN(ary);
     long new_len = len + argc;
     long capa;
     const VALUE *head, *sharedp;
 
-    if (ARY_SHARED_P(ary)) {
-	VALUE shared = ARY_SHARED(ary);
-	capa = RARRAY_LEN(shared);
-	if (ARY_SHARED_OCCUPIED(shared) && capa > new_len) {
-	    head = RARRAY_CONST_PTR(ary);
-	    sharedp = RARRAY_CONST_PTR(shared);
-	    goto makeroom_if_need;
-	}
-    }
-
     rb_ary_modify(ary);
     capa = ARY_CAPA(ary);
     if (capa - (capa >> 6) <= new_len) {
-	ary_double_capa(ary, new_len);
+        ary_double_capa(ary, new_len);
     }
 
     /* use shared array for big "queues" */
-    if (new_len > ARY_DEFAULT_SIZE * 4) {
-	/* make a room for unshifted items */
-	capa = ARY_CAPA(ary);
-	ary_make_shared(ary);
-
-	head = sharedp = RARRAY_CONST_PTR(ary);
-	goto makeroom;
-      makeroom_if_need:
-	if (head - sharedp < argc) {
-	    long room;
-	  makeroom:
-	    room = capa - new_len;
-	    room -= room >> 4;
-	    MEMMOVE((VALUE *)sharedp + argc + room, head, VALUE, len);
-	    head = sharedp + argc + room;
-	}
-	ARY_SET_PTR(ary, head - argc);
+    if (new_len > ARY_DEFAULT_SIZE * 4 && !ARY_EMBED_P(ary)) {
+        ary_verify(ary);
+
+        /* make a room for unshifted items */
+        capa = ARY_CAPA(ary);
+        ary_make_shared(ary);
+
+        head = sharedp = RARRAY_CONST_PTR_TRANSIENT(ary);
+        return make_room_for_unshift(ary, head, (void *)sharedp, argc, capa, len);
     }
     else {
-	/* sliding items */
-	RARRAY_PTR_USE(ary, ptr, {
-	    MEMMOVE(ptr + argc, ptr, VALUE, len);
-	});
+        /* sliding items */
+        RARRAY_PTR_USE_TRANSIENT(ary, ptr, {
+            MEMMOVE(ptr + argc, ptr, VALUE, len);
+        });
+
+        ary_verify(ary);
+        return ary;
+    }
+}
+
+static VALUE
+ary_ensure_room_for_unshift(VALUE ary, int argc)
+{
+    long len = RARRAY_LEN(ary);
+    long new_len = len + argc;
+
+    if (len > ARY_MAX_SIZE - argc) {
+        rb_raise(rb_eIndexError, "index %ld too big", new_len);
+    }
+    else if (! ARY_SHARED_P(ary)) {
+        return ary_modify_for_unshift(ary, argc);
+    }
+    else {
+        VALUE shared_root = ARY_SHARED_ROOT(ary);
+        long capa = RARRAY_LEN(shared_root);
+
+        if (! ARY_SHARED_ROOT_OCCUPIED(shared_root)) {
+            return ary_modify_for_unshift(ary, argc);
+        }
+        else if (new_len > capa) {
+            return ary_modify_for_unshift(ary, argc);
+        }
+        else {
+            const VALUE * head = RARRAY_CONST_PTR_TRANSIENT(ary);
+            void *sharedp = (void *)RARRAY_CONST_PTR_TRANSIENT(shared_root);
+
+            rb_ary_modify_check(ary);
+            return make_room_for_unshift(ary, head, sharedp, argc, capa, len);
+        }
     }
 }
 
 /*
  *  call-seq:
- *     ary.unshift(obj, ...)  -> ary
+ *    array.unshift(*objects) -> self
  *
- *  Prepends objects to the front of +self+, moving other elements upwards.
- *  See also Array#shift for the opposite effect.
+ *  Prepends the given +objects+ to +self+:
  *
- *     a = [ "b", "c", "d" ]
- *     a.unshift("a")   #=> ["a", "b", "c", "d"]
- *     a.unshift(1, 2)  #=> [ 1, 2, "a", "b", "c", "d"]
+ *    a = [:foo, 'bar', 2]
+ *    a.unshift(:bam, :bat) # => [:bam, :bat, :foo, "bar", 2]
+ *
+ *  Array#prepend is an alias for Array#unshift.
+ *
+ *  Related: #push, #pop, #shift.
  */
 
 static VALUE
 rb_ary_unshift_m(int argc, VALUE *argv, VALUE ary)
 {
     long len = RARRAY_LEN(ary);
+    VALUE target_ary;
 
     if (argc == 0) {
-	rb_ary_modify_check(ary);
-	return ary;
+        rb_ary_modify_check(ary);
+        return ary;
     }
 
-    ary_ensure_room_for_unshift(ary, argc);
-    ary_memcpy(ary, 0, argc, argv);
+    target_ary = ary_ensure_room_for_unshift(ary, argc);
+    ary_memcpy0(ary, 0, argc, argv, target_ary);
     ARY_SET_LEN(ary, len + argc);
     return ary;
 }
@@ -1170,7 +1827,7 @@ rb_ary_elt(VALUE ary, long offset)
     long len = RARRAY_LEN(ary);
     if (len == 0) return Qnil;
     if (offset < 0 || len <= offset) {
-	return Qnil;
+        return Qnil;
     }
     return RARRAY_AREF(ary, offset);
 }
@@ -1178,14 +1835,11 @@ rb_ary_elt(VALUE ary, long offset)
 VALUE
 rb_ary_entry(VALUE ary, long offset)
 {
-    if (offset < 0) {
-	offset += RARRAY_LEN(ary);
-    }
-    return rb_ary_elt(ary, offset);
+    return rb_ary_entry_internal(ary, offset);
 }
 
 VALUE
-rb_ary_subseq(VALUE ary, long beg, long len)
+rb_ary_subseq_step(VALUE ary, long beg, long len, long step)
 {
     VALUE klass;
     long alen = RARRAY_LEN(ary);
@@ -1194,98 +1848,186 @@ rb_ary_subseq(VALUE ary, long beg, long len)
     if (beg < 0 || len < 0) return Qnil;
 
     if (alen < len || alen < beg + len) {
-	len = alen - beg;
+        len = alen - beg;
     }
-    klass = rb_obj_class(ary);
+    klass = rb_cArray;
     if (len == 0) return ary_new(klass, 0);
+    if (step == 0)
+        rb_raise(rb_eArgError, "slice step cannot be zero");
+    if (step == 1)
+        return ary_make_partial(ary, klass, beg, len);
+    else
+        return ary_make_partial_step(ary, klass, beg, len, step);
+}
 
-    return ary_make_partial(ary, klass, beg, len);
+VALUE
+rb_ary_subseq(VALUE ary, long beg, long len)
+{
+    return rb_ary_subseq_step(ary, beg, len, 1);
 }
 
+static VALUE rb_ary_aref2(VALUE ary, VALUE b, VALUE e);
+
 /*
  *  call-seq:
- *     ary[index]                -> obj     or nil
- *     ary[start, length]        -> new_ary or nil
- *     ary[range]                -> new_ary or nil
- *     ary.slice(index)          -> obj     or nil
- *     ary.slice(start, length)  -> new_ary or nil
- *     ary.slice(range)          -> new_ary or nil
- *
- *  Element Reference --- Returns the element at +index+, or returns a
- *  subarray starting at the +start+ index and continuing for +length+
- *  elements, or returns a subarray specified by +range+ of indices.
- *
- *  Negative indices count backward from the end of the array (-1 is the last
- *  element).  For +start+ and +range+ cases the starting index is just before
- *  an element.  Additionally, an empty array is returned when the starting
- *  index for an element range is at the end of the array.
- *
- *  Returns +nil+ if the index (or starting index) are out of range.
- *
- *     a = [ "a", "b", "c", "d", "e" ]
- *     a[2] +  a[0] + a[1]    #=> "cab"
- *     a[6]                   #=> nil
- *     a[1, 2]                #=> [ "b", "c" ]
- *     a[1..3]                #=> [ "b", "c", "d" ]
- *     a[4..7]                #=> [ "e" ]
- *     a[6..10]               #=> nil
- *     a[-3, 3]               #=> [ "c", "d", "e" ]
- *     # special cases
- *     a[5]                   #=> nil
- *     a[6, 1]                #=> nil
- *     a[5, 1]                #=> []
- *     a[5..10]               #=> []
+ *    array[index] -> object or nil
+ *    array[start, length] -> object or nil
+ *    array[range] -> object or nil
+ *    array[aseq] -> object or nil
+ *    array.slice(index) -> object or nil
+ *    array.slice(start, length) -> object or nil
+ *    array.slice(range) -> object or nil
+ *    array.slice(aseq) -> object or nil
+ *
+ *  Returns elements from +self+; does not modify +self+.
+ *
+ *  When a single \Integer argument +index+ is given, returns the element at offset +index+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[0] # => :foo
+ *    a[2] # => 2
+ *    a # => [:foo, "bar", 2]
+ *
+ *  If +index+ is negative, counts relative to the end of +self+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[-1] # => 2
+ *    a[-2] # => "bar"
+ *
+ *  If +index+ is out of range, returns +nil+.
+ *
+ *  When two \Integer arguments +start+ and +length+ are given,
+ *  returns a new \Array of size +length+ containing successive elements beginning at offset +start+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[0, 2] # => [:foo, "bar"]
+ *    a[1, 2] # => ["bar", 2]
+ *
+ *  If <tt>start + length</tt> is greater than <tt>self.length</tt>,
+ *  returns all elements from offset +start+ to the end:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[0, 4] # => [:foo, "bar", 2]
+ *    a[1, 3] # => ["bar", 2]
+ *    a[2, 2] # => [2]
+ *
+ *  If <tt>start == self.size</tt> and <tt>length >= 0</tt>,
+ *  returns a new empty \Array.
+ *
+ *  If +length+ is negative, returns +nil+.
+ *
+ *  When a single \Range argument +range+ is given,
+ *  treats <tt>range.min</tt> as +start+ above
+ *  and <tt>range.size</tt> as +length+ above:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[0..1] # => [:foo, "bar"]
+ *    a[1..2] # => ["bar", 2]
+ *
+ *  Special case: If <tt>range.start == a.size</tt>, returns a new empty \Array.
+ *
+ *  If <tt>range.end</tt> is negative, calculates the end index from the end:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[0..-1] # => [:foo, "bar", 2]
+ *    a[0..-2] # => [:foo, "bar"]
+ *    a[0..-3] # => [:foo]
+ *
+ *  If <tt>range.start</tt> is negative, calculates the start index from the end:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[-1..2] # => [2]
+ *    a[-2..2] # => ["bar", 2]
+ *    a[-3..2] # => [:foo, "bar", 2]
+ *
+ *  If <tt>range.start</tt> is larger than the array size, returns +nil+.
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[4..1] # => nil
+ *    a[4..0] # => nil
+ *    a[4..-1] # => nil
+ *
+ *  When a single Enumerator::ArithmeticSequence argument +aseq+ is given,
+ *  returns an \Array of elements corresponding to the indexes produced by
+ *  the sequence.
+ *
+ *    a = ['--', 'data1', '--', 'data2', '--', 'data3']
+ *    a[(1..).step(2)] # => ["data1", "data2", "data3"]
+ *
+ *  Unlike slicing with range, if the start or the end of the arithmetic sequence
+ *  is larger than array size, throws RangeError.
+ *
+ *    a = ['--', 'data1', '--', 'data2', '--', 'data3']
+ *    a[(1..11).step(2)]
+ *    # RangeError (((1..11).step(2)) out of range)
+ *    a[(7..).step(2)]
+ *    # RangeError (((7..).step(2)) out of range)
+ *
+ *  If given a single argument, and its type is not one of the listed, tries to
+ *  convert it to Integer, and raises if it is impossible:
  *
+ *    a = [:foo, 'bar', 2]
+ *    # Raises TypeError (no implicit conversion of Symbol into Integer):
+ *    a[:foo]
+ *
+ *  Array#slice is an alias for Array#[].
  */
 
 VALUE
-rb_ary_aref(int argc, VALUE *argv, VALUE ary)
+rb_ary_aref(int argc, const VALUE *argv, VALUE ary)
 {
-    VALUE arg;
-    long beg, len;
-
+    rb_check_arity(argc, 1, 2);
     if (argc == 2) {
-	beg = NUM2LONG(argv[0]);
-	len = NUM2LONG(argv[1]);
-	if (beg < 0) {
-	    beg += RARRAY_LEN(ary);
-	}
-	return rb_ary_subseq(ary, beg, len);
+        return rb_ary_aref2(ary, argv[0], argv[1]);
     }
-    if (argc != 1) {
-	rb_scan_args(argc, argv, "11", NULL, NULL);
+    return rb_ary_aref1(ary, argv[0]);
+}
+
+static VALUE
+rb_ary_aref2(VALUE ary, VALUE b, VALUE e)
+{
+    long beg = NUM2LONG(b);
+    long len = NUM2LONG(e);
+    if (beg < 0) {
+        beg += RARRAY_LEN(ary);
     }
-    arg = argv[0];
+    return rb_ary_subseq(ary, beg, len);
+}
+
+MJIT_FUNC_EXPORTED VALUE
+rb_ary_aref1(VALUE ary, VALUE arg)
+{
+    long beg, len, step;
+
     /* special case - speeding up */
     if (FIXNUM_P(arg)) {
-	return rb_ary_entry(ary, FIX2LONG(arg));
+        return rb_ary_entry(ary, FIX2LONG(arg));
     }
-    /* check if idx is Range */
-    switch (rb_range_beg_len(arg, &beg, &len, RARRAY_LEN(ary), 0)) {
+    /* check if idx is Range or ArithmeticSequence */
+    switch (rb_arithmetic_sequence_beg_len_step(arg, &beg, &len, &step, RARRAY_LEN(ary), 0)) {
       case Qfalse:
-	break;
+        break;
       case Qnil:
-	return Qnil;
+        return Qnil;
       default:
-	return rb_ary_subseq(ary, beg, len);
+        return rb_ary_subseq_step(ary, beg, len, step);
     }
+
     return rb_ary_entry(ary, NUM2LONG(arg));
 }
 
 /*
  *  call-seq:
- *     ary.at(index)   ->   obj  or nil
+ *    array.at(index) -> object
  *
- *  Returns the element at +index+. A negative index counts from the end of
- *  +self+. Returns +nil+ if the index is out of range. See also
- *  Array#[].
+ *  Returns the element at \Integer offset +index+; does not modify +self+.
+ *    a = [:foo, 'bar', 2]
+ *    a.at(0) # => :foo
+ *    a.at(2) # => 2
  *
- *     a = [ "a", "b", "c", "d", "e" ]
- *     a.at(0)     #=> "a"
- *     a.at(-1)    #=> "e"
  */
 
-static VALUE
+VALUE
 rb_ary_at(VALUE ary, VALUE pos)
 {
     return rb_ary_entry(ary, NUM2LONG(pos));
@@ -1293,80 +2035,131 @@ rb_ary_at(VALUE ary, VALUE pos)
 
 /*
  *  call-seq:
- *     ary.first     ->   obj or nil
- *     ary.first(n)  ->   new_ary
+ *    array.first -> object or nil
+ *    array.first(n) -> new_array
+ *
+ *  Returns elements from +self+; does not modify +self+.
+ *
+ *  When no argument is given, returns the first element:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.first # => :foo
+ *    a # => [:foo, "bar", 2]
+ *
+ *  If +self+ is empty, returns +nil+.
+ *
+ *  When non-negative \Integer argument +n+ is given,
+ *  returns the first +n+ elements in a new \Array:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.first(2) # => [:foo, "bar"]
  *
- *  Returns the first element, or the first +n+ elements, of the array.
- *  If the array is empty, the first form returns +nil+, and the
- *  second form returns an empty array. See also Array#last for
- *  the opposite effect.
+ *  If <tt>n >= array.size</tt>, returns all elements:
  *
- *     a = [ "q", "r", "s", "t" ]
- *     a.first     #=> "q"
- *     a.first(2)  #=> ["q", "r"]
+ *    a = [:foo, 'bar', 2]
+ *    a.first(50) # => [:foo, "bar", 2]
+ *
+ *  If <tt>n == 0</tt> returns an new empty \Array:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.first(0) # []
+ *
+ *  Related: #last.
  */
-
 static VALUE
 rb_ary_first(int argc, VALUE *argv, VALUE ary)
 {
     if (argc == 0) {
-	if (RARRAY_LEN(ary) == 0) return Qnil;
-	return RARRAY_AREF(ary, 0);
+        if (RARRAY_LEN(ary) == 0) return Qnil;
+        return RARRAY_AREF(ary, 0);
     }
     else {
-	return ary_take_first_or_last(argc, argv, ary, ARY_TAKE_FIRST);
+        return ary_take_first_or_last(argc, argv, ary, ARY_TAKE_FIRST);
     }
 }
 
 /*
  *  call-seq:
- *     ary.last     ->  obj or nil
- *     ary.last(n)  ->  new_ary
+ *    array.last  -> object or nil
+ *    array.last(n) -> new_array
+ *
+ *  Returns elements from +self+; +self+ is not modified.
+ *
+ *  When no argument is given, returns the last element:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.last # => 2
+ *    a # => [:foo, "bar", 2]
  *
- *  Returns the last element(s) of +self+. If the array is empty,
- *  the first form returns +nil+.
+ *  If +self+ is empty, returns +nil+.
  *
- *  See also Array#first for the opposite effect.
+ *  When non-negative \Integer argument +n+ is given,
+ *  returns the last +n+ elements in a new \Array:
  *
- *     a = [ "w", "x", "y", "z" ]
- *     a.last     #=> "z"
- *     a.last(2)  #=> ["y", "z"]
+ *    a = [:foo, 'bar', 2]
+ *    a.last(2) # => ["bar", 2]
+ *
+ *  If <tt>n >= array.size</tt>, returns all elements:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.last(50) # => [:foo, "bar", 2]
+ *
+ *  If <tt>n == 0</tt>, returns an new empty \Array:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.last(0) # []
+ *
+ *  Related: #first.
  */
 
 VALUE
-rb_ary_last(int argc, VALUE *argv, VALUE ary)
+rb_ary_last(int argc, const VALUE *argv, VALUE ary)
 {
     if (argc == 0) {
-	long len = RARRAY_LEN(ary);
-	if (len == 0) return Qnil;
-	return RARRAY_AREF(ary, len-1);
+        long len = RARRAY_LEN(ary);
+        if (len == 0) return Qnil;
+        return RARRAY_AREF(ary, len-1);
     }
     else {
-	return ary_take_first_or_last(argc, argv, ary, ARY_TAKE_LAST);
+        return ary_take_first_or_last(argc, argv, ary, ARY_TAKE_LAST);
     }
 }
 
 /*
  *  call-seq:
- *     ary.fetch(index)                    -> obj
- *     ary.fetch(index, default)           -> obj
- *     ary.fetch(index) { |index| block }  -> obj
- *
- *  Tries to return the element at position +index+, but throws an IndexError
- *  exception if the referenced +index+ lies outside of the array bounds.  This
- *  error can be prevented by supplying a second argument, which will act as a
- *  +default+ value.
- *
- *  Alternatively, if a block is given it will only be executed when an
- *  invalid +index+ is referenced.  Negative values of +index+ count from the
- *  end of the array.
- *
- *     a = [ 11, 22, 33, 44 ]
- *     a.fetch(1)               #=> 22
- *     a.fetch(-1)              #=> 44
- *     a.fetch(4, 'cat')        #=> "cat"
- *     a.fetch(100) { |i| puts "#{i} is out of bounds" }
- *                              #=> "100 is out of bounds"
+ *    array.fetch(index) -> element
+ *    array.fetch(index, default_value) -> element
+ *    array.fetch(index) {|index| ... } -> element
+ *
+ *  Returns the element at offset  +index+.
+ *
+ *  With the single \Integer argument +index+,
+ *  returns the element at offset +index+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.fetch(1) # => "bar"
+ *
+ *  If +index+ is negative, counts from the end of the array:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.fetch(-1) # => 2
+ *    a.fetch(-2) # => "bar"
+ *
+ *  With arguments +index+ and +default_value+,
+ *  returns the element at offset +index+ if index is in range,
+ *  otherwise returns +default_value+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.fetch(1, nil) # => "bar"
+ *
+ *  With argument +index+ and a block,
+ *  returns the element at offset +index+ if index is in range
+ *  (and the block is not called); otherwise calls the block with index and returns its return value:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.fetch(1) {|index| raise 'Cannot happen' } # => "bar"
+ *    a.fetch(50) {|index| "Value for #{index}" } # => "Value for 50"
+ *
  */
 
 static VALUE
@@ -1379,149 +2172,152 @@ rb_ary_fetch(int argc, VALUE *argv, VALUE ary)
     rb_scan_args(argc, argv, "11", &pos, &ifnone);
     block_given = rb_block_given_p();
     if (block_given && argc == 2) {
-	rb_warn("block supersedes default value argument");
+        rb_warn("block supersedes default value argument");
     }
     idx = NUM2LONG(pos);
 
     if (idx < 0) {
-	idx +=  RARRAY_LEN(ary);
+        idx +=  RARRAY_LEN(ary);
     }
     if (idx < 0 || RARRAY_LEN(ary) <= idx) {
-	if (block_given) return rb_yield(pos);
-	if (argc == 1) {
-	    rb_raise(rb_eIndexError, "index %ld outside of array bounds: %ld...%ld",
-			idx - (idx < 0 ? RARRAY_LEN(ary) : 0), -RARRAY_LEN(ary), RARRAY_LEN(ary));
-	}
-	return ifnone;
+        if (block_given) return rb_yield(pos);
+        if (argc == 1) {
+            rb_raise(rb_eIndexError, "index %ld outside of array bounds: %ld...%ld",
+                        idx - (idx < 0 ? RARRAY_LEN(ary) : 0), -RARRAY_LEN(ary), RARRAY_LEN(ary));
+        }
+        return ifnone;
     }
     return RARRAY_AREF(ary, idx);
 }
 
 /*
  *  call-seq:
- *     ary.find_index(obj)             ->  int or nil
- *     ary.find_index { |item| block } ->  int or nil
- *     ary.find_index                  ->  Enumerator
- *     ary.index(obj)             ->  int or nil
- *     ary.index { |item| block } ->  int or nil
- *     ary.index                  ->  Enumerator
+ *    array.index(object) -> integer or nil
+ *    array.index {|element| ... } -> integer or nil
+ *    array.index -> new_enumerator
  *
- *  Returns the _index_ of the first object in +ary+ such that the object is
- *  <code>==</code> to +obj+.
+ *  Returns the index of a specified element.
  *
- *  If a block is given instead of an argument, returns the _index_ of the
- *  first object for which the block returns +true+.  Returns +nil+ if no
- *  match is found.
+ *  When argument +object+ is given but no block,
+ *  returns the index of the first element +element+
+ *  for which <tt>object == element</tt>:
  *
- *  See also Array#rindex.
+ *    a = [:foo, 'bar', 2, 'bar']
+ *    a.index('bar') # => 1
  *
- *  An Enumerator is returned if neither a block nor argument is given.
+ *  Returns +nil+ if no such element found.
  *
- *     a = [ "a", "b", "c" ]
- *     a.index("b")              #=> 1
- *     a.index("z")              #=> nil
- *     a.index { |x| x == "b" }  #=> 1
+ *  When both argument +object+ and a block are given,
+ *  calls the block with each successive element;
+ *  returns the index of the first element for which the block returns a truthy value:
+ *
+ *    a = [:foo, 'bar', 2, 'bar']
+ *    a.index {|element| element == 'bar' } # => 1
+ *
+ *  Returns +nil+ if the block never returns a truthy value.
+ *
+ *  When neither an argument nor a block is given, returns a new Enumerator:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    e = a.index
+ *    e # => #<Enumerator: [:foo, "bar", 2]:index>
+ *    e.each {|element| element == 'bar' } # => 1
+ *
+ *  Array#find_index is an alias for Array#index.
+ *
+ *  Related: #rindex.
  */
 
 static VALUE
 rb_ary_index(int argc, VALUE *argv, VALUE ary)
 {
-    const VALUE *ptr;
     VALUE val;
-    long i, len;
+    long i;
 
     if (argc == 0) {
-	RETURN_ENUMERATOR(ary, 0, 0);
-	for (i=0; i<RARRAY_LEN(ary); i++) {
-	    if (RTEST(rb_yield(RARRAY_AREF(ary, i)))) {
-		return LONG2NUM(i);
-	    }
-	}
-	return Qnil;
+        RETURN_ENUMERATOR(ary, 0, 0);
+        for (i=0; i<RARRAY_LEN(ary); i++) {
+            if (RTEST(rb_yield(RARRAY_AREF(ary, i)))) {
+                return LONG2NUM(i);
+            }
+        }
+        return Qnil;
     }
     rb_check_arity(argc, 0, 1);
     val = argv[0];
     if (rb_block_given_p())
-	rb_warn("given block not used");
-    len = RARRAY_LEN(ary);
-    ptr = RARRAY_CONST_PTR(ary);
-    for (i=0; i<len; i++) {
-	VALUE e = ptr[i];
-	switch (rb_equal_opt(e, val)) {
-	  case Qundef:
-	    if (!rb_equal(e, val)) break;
-	  case Qtrue:
-	    return LONG2NUM(i);
-	  case Qfalse:
-	    continue;
-	}
-	len = RARRAY_LEN(ary);
-	ptr = RARRAY_CONST_PTR(ary);
+        rb_warn("given block not used");
+    for (i=0; i<RARRAY_LEN(ary); i++) {
+        VALUE e = RARRAY_AREF(ary, i);
+        if (rb_equal(e, val)) {
+            return LONG2NUM(i);
+        }
     }
     return Qnil;
 }
 
 /*
  *  call-seq:
- *     ary.rindex(obj)             ->  int or nil
- *     ary.rindex { |item| block } ->  int or nil
- *     ary.rindex                  ->  Enumerator
+ *    array.rindex(object) -> integer or nil
+ *    array.rindex {|element| ... } -> integer or nil
+ *    array.rindex -> new_enumerator
+ *
+ *  Returns the index of the last element for which <tt>object == element</tt>.
+ *
+ *  When argument +object+ is given but no block, returns the index of the last such element found:
  *
- *  Returns the _index_ of the last object in +self+ <code>==</code> to +obj+.
+ *    a = [:foo, 'bar', 2, 'bar']
+ *    a.rindex('bar') # => 3
  *
- *  If a block is given instead of an argument, returns the _index_ of the
- *  first object for which the block returns +true+, starting from the last
- *  object.
+ *  Returns +nil+ if no such object found.
  *
- *  Returns +nil+ if no match is found.
+ *  When a block is given but no argument, calls the block with each successive element;
+ *  returns the index of the last element for which the block returns a truthy value:
  *
- *  See also Array#index.
+ *    a = [:foo, 'bar', 2, 'bar']
+ *    a.rindex {|element| element == 'bar' } # => 3
  *
- *  If neither block nor argument is given, an Enumerator is returned instead.
+ *  Returns +nil+ if the block never returns a truthy value.
  *
- *     a = [ "a", "b", "b", "b", "c" ]
- *     a.rindex("b")             #=> 3
- *     a.rindex("z")             #=> nil
- *     a.rindex { |x| x == "b" } #=> 3
+ *  When neither an argument nor a block is given, returns a new \Enumerator:
+ *
+ *    a = [:foo, 'bar', 2, 'bar']
+ *    e = a.rindex
+ *    e # => #<Enumerator: [:foo, "bar", 2, "bar"]:rindex>
+ *    e.each {|element| element == 'bar' } # => 3
+ *
+ *  Related: #index.
  */
 
 static VALUE
 rb_ary_rindex(int argc, VALUE *argv, VALUE ary)
 {
-    const VALUE *ptr;
     VALUE val;
     long i = RARRAY_LEN(ary), len;
 
     if (argc == 0) {
-	RETURN_ENUMERATOR(ary, 0, 0);
-	while (i--) {
-	    if (RTEST(rb_yield(RARRAY_AREF(ary, i))))
-		return LONG2NUM(i);
-	    if (i > (len = RARRAY_LEN(ary))) {
-		i = len;
-	    }
-	}
-	return Qnil;
+        RETURN_ENUMERATOR(ary, 0, 0);
+        while (i--) {
+            if (RTEST(rb_yield(RARRAY_AREF(ary, i))))
+                return LONG2NUM(i);
+            if (i > (len = RARRAY_LEN(ary))) {
+                i = len;
+            }
+        }
+        return Qnil;
     }
     rb_check_arity(argc, 0, 1);
     val = argv[0];
     if (rb_block_given_p())
-	rb_warn("given block not used");
-    ptr = RARRAY_CONST_PTR(ary);
+        rb_warn("given block not used");
     while (i--) {
-	VALUE e = ptr[i];
-	switch (rb_equal_opt(e, val)) {
-	  case Qundef:
-	    if (!rb_equal(e, val)) break;
-	  case Qtrue:
-	    return LONG2NUM(i);
-	  case Qfalse:
-	    continue;
-	}
-	if (i > (len = RARRAY_LEN(ary))) {
-	    i = len;
-	}
-	ptr = RARRAY_CONST_PTR(ary);
+        VALUE e = RARRAY_AREF(ary, i);
+        if (rb_equal(e, val)) {
+            return LONG2NUM(i);
+        }
+        if (i > RARRAY_LEN(ary)) {
+            break;
+        }
     }
     return Qnil;
 }
@@ -1536,62 +2332,72 @@ rb_ary_to_ary(VALUE obj)
 }
 
 static void
-rb_ary_splice(VALUE ary, long beg, long len, VALUE rpl)
+rb_ary_splice(VALUE ary, long beg, long len, const VALUE *rptr, long rlen)
 {
-    long rlen;
     long olen;
+    long rofs;
 
     if (len < 0) rb_raise(rb_eIndexError, "negative length (%ld)", len);
     olen = RARRAY_LEN(ary);
     if (beg < 0) {
-	beg += olen;
-	if (beg < 0) {
-	    rb_raise(rb_eIndexError, "index %ld too small for array; minimum: %ld",
-		     beg - olen, -olen);
-	}
+        beg += olen;
+        if (beg < 0) {
+            rb_raise(rb_eIndexError, "index %ld too small for array; minimum: %ld",
+                     beg - olen, -olen);
+        }
     }
     if (olen < len || olen < beg + len) {
-	len = olen - beg;
+        len = olen - beg;
     }
 
-    if (rpl == Qundef) {
-	rlen = 0;
-    }
-    else {
-	rpl = rb_ary_to_ary(rpl);
-	rlen = RARRAY_LEN(rpl);
-	olen = RARRAY_LEN(ary);	/* ary may be resized in rpl.to_ary too */
+    {
+        const VALUE *optr = RARRAY_CONST_PTR_TRANSIENT(ary);
+        rofs = (rptr >= optr && rptr < optr + olen) ? rptr - optr : -1;
     }
+
     if (beg >= olen) {
-	if (beg > ARY_MAX_SIZE - rlen) {
-	    rb_raise(rb_eIndexError, "index %ld too big", beg);
-	}
-	ary_ensure_room_for_push(ary, rlen-len); /* len is 0 or negative */
-	len = beg + rlen;
-	ary_mem_clear(ary, olen, beg - olen);
-	if (rlen > 0) {
-	    ary_memcpy(ary, beg, rlen, RARRAY_CONST_PTR(rpl));
-	}
-	ARY_SET_LEN(ary, len);
+        VALUE target_ary;
+        if (beg > ARY_MAX_SIZE - rlen) {
+            rb_raise(rb_eIndexError, "index %ld too big", beg);
+        }
+        target_ary = ary_ensure_room_for_push(ary, rlen-len); /* len is 0 or negative */
+        len = beg + rlen;
+        ary_mem_clear(ary, olen, beg - olen);
+        if (rlen > 0) {
+            if (rofs != -1) rptr = RARRAY_CONST_PTR_TRANSIENT(ary) + rofs;
+            ary_memcpy0(ary, beg, rlen, rptr, target_ary);
+        }
+        ARY_SET_LEN(ary, len);
     }
     else {
-	long alen;
+        long alen;
 
-	rb_ary_modify(ary);
-	alen = olen + rlen - len;
-	if (alen >= ARY_CAPA(ary)) {
-	    ary_double_capa(ary, alen);
-	}
+        if (olen - len > ARY_MAX_SIZE - rlen) {
+            rb_raise(rb_eIndexError, "index %ld too big", olen + rlen - len);
+        }
+        rb_ary_modify(ary);
+        alen = olen + rlen - len;
+        if (alen >= ARY_CAPA(ary)) {
+            ary_double_capa(ary, alen);
+        }
 
-	if (len != rlen) {
-	    RARRAY_PTR_USE(ary, ptr,
-			   MEMMOVE(ptr + beg + rlen, ptr + beg + len,
-				   VALUE, olen - (beg + len)));
-	    ARY_SET_LEN(ary, alen);
-	}
-	if (rlen > 0) {
-	    MEMMOVE(RARRAY_PTR(ary) + beg, RARRAY_CONST_PTR(rpl), VALUE, rlen);
-	}
+        if (len != rlen) {
+            RARRAY_PTR_USE_TRANSIENT(ary, ptr,
+                                     MEMMOVE(ptr + beg + rlen, ptr + beg + len,
+                                             VALUE, olen - (beg + len)));
+            ARY_SET_LEN(ary, alen);
+        }
+        if (rlen > 0) {
+            if (rofs != -1) rptr = RARRAY_CONST_PTR_TRANSIENT(ary) + rofs;
+            /* give up wb-protected ary */
+            RB_OBJ_WB_UNPROTECT_FOR(ARRAY, ary);
+
+            /* do not use RARRAY_PTR() because it can causes GC.
+             * ary can contain T_NONE object because it is not cleared.
+             */
+            RARRAY_PTR_USE_TRANSIENT(ary, ptr,
+                                     MEMMOVE(ptr + beg, rptr, VALUE, rlen));
+        }
     }
 }
 
@@ -1602,22 +2408,14 @@ rb_ary_set_len(VALUE ary, long len)
 
     rb_ary_modify_check(ary);
     if (ARY_SHARED_P(ary)) {
-	rb_raise(rb_eRuntimeError, "can't set length of shared ");
+        rb_raise(rb_eRuntimeError, "can't set length of shared ");
     }
     if (len > (capa = (long)ARY_CAPA(ary))) {
-	rb_bug("probable buffer overflow: %ld for %ld", len, capa);
+        rb_bug("probable buffer overflow: %ld for %ld", len, capa);
     }
     ARY_SET_LEN(ary, len);
 }
 
-/*!
- * expands or shrinks \a ary to \a len elements.
- * expanded region will be filled with Qnil.
- * \param ary  an array
- * \param len  new size
- * \return     \a ary
- * \post       the size of \a ary is \a len.
- */
 VALUE
 rb_ary_resize(VALUE ary, long len)
 {
@@ -1627,68 +2425,170 @@ rb_ary_resize(VALUE ary, long len)
     olen = RARRAY_LEN(ary);
     if (len == olen) return ary;
     if (len > ARY_MAX_SIZE) {
-	rb_raise(rb_eIndexError, "index %ld too big", len);
+        rb_raise(rb_eIndexError, "index %ld too big", len);
     }
     if (len > olen) {
-	if (len >= ARY_CAPA(ary)) {
-	    ary_double_capa(ary, len);
-	}
-	ary_mem_clear(ary, olen, len - olen);
-	ARY_SET_LEN(ary, len);
+        if (len >= ARY_CAPA(ary)) {
+            ary_double_capa(ary, len);
+        }
+        ary_mem_clear(ary, olen, len - olen);
+        ARY_SET_LEN(ary, len);
     }
     else if (ARY_EMBED_P(ary)) {
         ARY_SET_EMBED_LEN(ary, len);
     }
-    else if (len <= RARRAY_EMBED_LEN_MAX) {
-	VALUE tmp[RARRAY_EMBED_LEN_MAX];
-	MEMCPY(tmp, ARY_HEAP_PTR(ary), VALUE, len);
-	ary_discard(ary);
-	MEMCPY((VALUE *)ARY_EMBED_PTR(ary), tmp, VALUE, len); /* WB: no new reference */
+    else if (len <= ary_embed_capa(ary)) {
+        const VALUE *ptr = ARY_HEAP_PTR(ary);
+        long ptr_capa = ARY_HEAP_SIZE(ary);
+        bool is_malloc_ptr = !ARY_SHARED_P(ary) && !RARRAY_TRANSIENT_P(ary);
+
+        FL_UNSET(ary, RARRAY_TRANSIENT_FLAG);
+        FL_SET_EMBED(ary);
+
+        MEMCPY((VALUE *)ARY_EMBED_PTR(ary), ptr, VALUE, len); /* WB: no new reference */
         ARY_SET_EMBED_LEN(ary, len);
+
+        if (is_malloc_ptr) ruby_sized_xfree((void *)ptr, ptr_capa);
     }
     else {
-	if (olen > len + ARY_DEFAULT_SIZE) {
-	    SIZED_REALLOC_N(RARRAY(ary)->as.heap.ptr, VALUE, len, RARRAY(ary)->as.heap.aux.capa);
-	    ARY_SET_CAPA(ary, len);
-	}
-	ARY_SET_HEAP_LEN(ary, len);
+        if (olen > len + ARY_DEFAULT_SIZE) {
+            size_t new_capa = ary_heap_realloc(ary, len);
+            ARY_SET_CAPA(ary, new_capa);
+        }
+        ARY_SET_HEAP_LEN(ary, len);
     }
+    ary_verify(ary);
     return ary;
 }
 
+static VALUE
+ary_aset_by_rb_ary_store(VALUE ary, long key, VALUE val)
+{
+    rb_ary_store(ary, key, val);
+    return val;
+}
+
+static VALUE
+ary_aset_by_rb_ary_splice(VALUE ary, long beg, long len, VALUE val)
+{
+    VALUE rpl = rb_ary_to_ary(val);
+    rb_ary_splice(ary, beg, len, RARRAY_CONST_PTR_TRANSIENT(rpl), RARRAY_LEN(rpl));
+    RB_GC_GUARD(rpl);
+    return val;
+}
+
 /*
  *  call-seq:
- *     ary[index]         = obj                      ->  obj
- *     ary[start, length] = obj or other_ary or nil  ->  obj or other_ary or nil
- *     ary[range]         = obj or other_ary or nil  ->  obj or other_ary or nil
- *
- *  Element Assignment --- Sets the element at +index+, or replaces a subarray
- *  from the +start+ index for +length+ elements, or replaces a subarray
- *  specified by the +range+ of indices.
- *
- *  If indices are greater than the current capacity of the array, the array
- *  grows automatically.  Elements are inserted into the array at +start+ if
- *  +length+ is zero.
- *
- *  Negative indices will count backward from the end of the array.  For
- *  +start+ and +range+ cases the starting index is just before an element.
- *
- *  An IndexError is raised if a negative index points past the beginning of
- *  the array.
- *
- *  See also Array#push, and Array#unshift.
- *
- *     a = Array.new
- *     a[4] = "4";                 #=> [nil, nil, nil, nil, "4"]
- *     a[0, 3] = [ 'a', 'b', 'c' ] #=> ["a", "b", "c", nil, "4"]
- *     a[1..2] = [ 1, 2 ]          #=> ["a", 1, 2, nil, "4"]
- *     a[0, 2] = "?"               #=> ["?", 2, nil, "4"]
- *     a[0..2] = "A"               #=> ["A", "4"]
- *     a[-1]   = "Z"               #=> ["A", "Z"]
- *     a[1..-1] = nil              #=> ["A", nil]
- *     a[1..-1] = []               #=> ["A"]
- *     a[0, 0] = [ 1, 2 ]          #=> [1, 2, "A"]
- *     a[3, 0] = "B"               #=> [1, 2, "A", "B"]
+ *    array[index] = object -> object
+ *    array[start, length] = object -> object
+ *    array[range] = object -> object
+ *
+ *  Assigns elements in +self+; returns the given +object+.
+ *
+ *  When \Integer argument +index+ is given, assigns +object+ to an element in +self+.
+ *
+ *  If +index+ is non-negative, assigns +object+ the element at offset +index+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[0] = 'foo' # => "foo"
+ *    a # => ["foo", "bar", 2]
+ *
+ *  If +index+ is greater than <tt>self.length</tt>, extends the array:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[7] = 'foo' # => "foo"
+ *    a # => [:foo, "bar", 2, nil, nil, nil, nil, "foo"]
+ *
+ *  If +index+ is negative, counts backwards from the end of the array:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[-1] = 'two' # => "two"
+ *    a # => [:foo, "bar", "two"]
+ *
+ *  When \Integer arguments +start+ and +length+ are given and +object+ is not an \Array,
+ *  removes <tt>length - 1</tt> elements beginning at offset +start+,
+ *  and assigns +object+ at offset +start+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[0, 2] = 'foo' # => "foo"
+ *    a # => ["foo", 2]
+ *
+ *  If +start+ is negative, counts backwards from the end of the array:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[-2, 2] = 'foo' # => "foo"
+ *    a # => [:foo, "foo"]
+ *
+ *  If +start+ is non-negative and outside the array (<tt> >= self.size</tt>),
+ *  extends the array with +nil+, assigns +object+ at offset +start+,
+ *  and ignores +length+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[6, 50] = 'foo' # => "foo"
+ *    a # => [:foo, "bar", 2, nil, nil, nil, "foo"]
+ *
+ *  If +length+ is zero, shifts elements at and following offset +start+
+ *  and assigns +object+ at offset +start+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[1, 0] = 'foo' # => "foo"
+ *    a # => [:foo, "foo", "bar", 2]
+ *
+ *  If +length+ is too large for the existing array, does not extend the array:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[1, 5] = 'foo' # => "foo"
+ *    a # => [:foo, "foo"]
+ *
+ *  When \Range argument +range+ is given and +object+ is an \Array,
+ *  removes <tt>length - 1</tt> elements beginning at offset +start+,
+ *  and assigns +object+ at offset +start+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[0..1] = 'foo' # => "foo"
+ *    a # => ["foo", 2]
+ *
+ *  if <tt>range.begin</tt> is negative, counts backwards from the end of the array:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[-2..2] = 'foo' # => "foo"
+ *    a # => [:foo, "foo"]
+ *
+ *  If the array length is less than <tt>range.begin</tt>,
+ *  assigns +object+ at offset <tt>range.begin</tt>, and ignores +length+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[6..50] = 'foo' # => "foo"
+ *    a # => [:foo, "bar", 2, nil, nil, nil, "foo"]
+ *
+ *  If <tt>range.end</tt> is zero, shifts elements at and following offset +start+
+ *  and assigns +object+ at offset +start+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[1..0] = 'foo' # => "foo"
+ *    a # => [:foo, "foo", "bar", 2]
+ *
+ *  If <tt>range.end</tt> is negative, assigns +object+ at offset +start+,
+ *  retains <tt>range.end.abs -1</tt> elements past that, and removes those beyond:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[1..-1] = 'foo' # => "foo"
+ *    a # => [:foo, "foo"]
+ *    a = [:foo, 'bar', 2]
+ *    a[1..-2] = 'foo' # => "foo"
+ *    a # => [:foo, "foo", 2]
+ *    a = [:foo, 'bar', 2]
+ *    a[1..-3] = 'foo' # => "foo"
+ *    a # => [:foo, "foo", "bar", 2]
+ *    a = [:foo, 'bar', 2]
+ *
+ *  If <tt>range.end</tt> is too large for the existing array,
+ *  replaces array elements, but does not extend the array with +nil+ values:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a[1..5] = 'foo' # => "foo"
+ *    a # => [:foo, "foo"]
+ *
  */
 
 static VALUE
@@ -1696,43 +2596,60 @@ rb_ary_aset(int argc, VALUE *argv, VALUE ary)
 {
     long offset, beg, len;
 
+    rb_check_arity(argc, 2, 3);
+    rb_ary_modify_check(ary);
     if (argc == 3) {
-	rb_ary_modify_check(ary);
-	beg = NUM2LONG(argv[0]);
-	len = NUM2LONG(argv[1]);
-	rb_ary_splice(ary, beg, len, argv[2]);
-	return argv[2];
+        beg = NUM2LONG(argv[0]);
+        len = NUM2LONG(argv[1]);
+        return ary_aset_by_rb_ary_splice(ary, beg, len, argv[2]);
     }
-    rb_check_arity(argc, 2, 2);
-    rb_ary_modify_check(ary);
     if (FIXNUM_P(argv[0])) {
-	offset = FIX2LONG(argv[0]);
-	goto fixnum;
+        offset = FIX2LONG(argv[0]);
+        return ary_aset_by_rb_ary_store(ary, offset, argv[1]);
     }
     if (rb_range_beg_len(argv[0], &beg, &len, RARRAY_LEN(ary), 1)) {
-	/* check if idx is Range */
-	rb_ary_splice(ary, beg, len, argv[1]);
-	return argv[1];
+        /* check if idx is Range */
+        return ary_aset_by_rb_ary_splice(ary, beg, len, argv[1]);
     }
 
     offset = NUM2LONG(argv[0]);
-fixnum:
-    rb_ary_store(ary, offset, argv[1]);
-    return argv[1];
+    return ary_aset_by_rb_ary_store(ary, offset, argv[1]);
 }
 
 /*
  *  call-seq:
- *     ary.insert(index, obj...)  -> ary
+ *    array.insert(index, *objects) -> self
+ *
+ *  Inserts given +objects+ before or after the element at \Integer index +offset+;
+ *  returns +self+.
+ *
+ *  When +index+ is non-negative, inserts all given +objects+
+ *  before the element at offset +index+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.insert(1, :bat, :bam) # => [:foo, :bat, :bam, "bar", 2]
+ *
+ *  Extends the array if +index+ is beyond the array (<tt>index >= self.size</tt>):
  *
- *  Inserts the given values before the element with the given +index+.
+ *    a = [:foo, 'bar', 2]
+ *    a.insert(5, :bat, :bam)
+ *    a # => [:foo, "bar", 2, nil, nil, :bat, :bam]
  *
- *  Negative indices count backwards from the end of the array, where +-1+ is
- *  the last element.
+ *  Does nothing if no objects given:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.insert(1)
+ *    a.insert(50)
+ *    a.insert(-50)
+ *    a # => [:foo, "bar", 2]
+ *
+ *  When +index+ is negative, inserts all given +objects+
+ *  _after_ the element at offset <tt>index+self.size</tt>:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.insert(-2, :bat, :bam)
+ *    a # => [:foo, "bar", :bat, :bam, 2]
  *
- *     a = %w{ a b c d }
- *     a.insert(2, 99)         #=> ["a", "b", 99, "c", "d"]
- *     a.insert(-2, 1, 2, 3)   #=> ["a", "b", 99, "c", 1, 2, 3, "d"]
  */
 
 static VALUE
@@ -1742,15 +2659,20 @@ rb_ary_insert(int argc, VALUE *argv, VALUE ary)
 
     rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);
     rb_ary_modify_check(ary);
-    if (argc == 1) return ary;
     pos = NUM2LONG(argv[0]);
+    if (argc == 1) return ary;
     if (pos == -1) {
-	pos = RARRAY_LEN(ary);
+        pos = RARRAY_LEN(ary);
     }
-    if (pos < 0) {
-	pos++;
+    else if (pos < 0) {
+        long minpos = -RARRAY_LEN(ary) - 1;
+        if (pos < minpos) {
+            rb_raise(rb_eIndexError, "index %ld too small for array; minimum: %ld",
+                     pos, minpos);
+        }
+        pos++;
     }
-    rb_ary_splice(ary, pos, 0, rb_ary_new4(argc - 1, argv + 1));
+    rb_ary_splice(ary, pos, 0, argv + 1, argc - 1);
     return ary;
 }
 
@@ -1765,51 +2687,104 @@ ary_enum_length(VALUE ary, VALUE args, VALUE eobj)
 
 /*
  *  call-seq:
- *     ary.each { |item| block }  -> ary
- *     ary.each                   -> Enumerator
+ *    array.each {|element| ... } -> self
+ *    array.each -> Enumerator
+ *
+ *  Iterates over array elements.
+ *
+ *  When a block given, passes each successive array element to the block;
+ *  returns +self+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.each {|element|  puts "#{element.class} #{element}" }
+ *
+ *  Output:
+ *
+ *    Symbol foo
+ *    String bar
+ *    Integer 2
+ *
+ *  Allows the array to be modified during iteration:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.each {|element| puts element; a.clear if element.to_s.start_with?('b') }
+ *
+ *  Output:
  *
- *  Calls the given block once for each element in +self+, passing that element
- *  as a parameter.
+ *    foo
+ *    bar
  *
- *  An Enumerator is returned if no block is given.
+ *  When no block given, returns a new \Enumerator:
+ *    a = [:foo, 'bar', 2]
  *
- *     a = [ "a", "b", "c" ]
- *     a.each {|x| print x, " -- " }
+ *    e = a.each
+ *    e # => #<Enumerator: [:foo, "bar", 2]:each>
+ *    a1 = e.each {|element|  puts "#{element.class} #{element}" }
  *
- *  produces:
+ *  Output:
  *
- *     a -- b -- c --
+ *    Symbol foo
+ *    String bar
+ *    Integer 2
+ *
+ *  Related: #each_index, #reverse_each.
  */
 
 VALUE
-rb_ary_each(VALUE array)
+rb_ary_each(VALUE ary)
 {
     long i;
-    volatile VALUE ary = array;
-
+    ary_verify(ary);
     RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
     for (i=0; i<RARRAY_LEN(ary); i++) {
-	rb_yield(RARRAY_AREF(ary, i));
+        rb_yield(RARRAY_AREF(ary, i));
     }
     return ary;
 }
 
 /*
  *  call-seq:
- *     ary.each_index { |index| block }  -> ary
- *     ary.each_index                    -> Enumerator
+ *    array.each_index {|index| ... } -> self
+ *    array.each_index -> Enumerator
+ *
+ *  Iterates over array indexes.
+ *
+ *  When a block given, passes each successive array index to the block;
+ *  returns +self+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.each_index {|index|  puts "#{index} #{a[index]}" }
+ *
+ *  Output:
+ *
+ *    0 foo
+ *    1 bar
+ *    2 2
+ *
+ *  Allows the array to be modified during iteration:
  *
- *  Same as Array#each, but passes the +index+ of the element instead of the
- *  element itself.
+ *    a = [:foo, 'bar', 2]
+ *    a.each_index {|index| puts index; a.clear if index > 0 }
  *
- *  An Enumerator is returned if no block is given.
+ *  Output:
  *
- *     a = [ "a", "b", "c" ]
- *     a.each_index {|x| print x, " -- " }
+ *    0
+ *    1
  *
- *  produces:
+ *  When no block given, returns a new \Enumerator:
  *
- *     0 -- 1 -- 2 --
+ *    a = [:foo, 'bar', 2]
+ *    e = a.each_index
+ *    e # => #<Enumerator: [:foo, "bar", 2]:each_index>
+ *    a1 = e.each {|index|  puts "#{index} #{a[index]}"}
+ *
+ *  Output:
+ *
+ *    0 foo
+ *    1 bar
+ *    2 2
+ *
+ *  Related: #each, #reverse_each.
  */
 
 static VALUE
@@ -1819,24 +2794,54 @@ rb_ary_each_index(VALUE ary)
     RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
 
     for (i=0; i<RARRAY_LEN(ary); i++) {
-	rb_yield(LONG2NUM(i));
+        rb_yield(LONG2NUM(i));
     }
     return ary;
 }
 
 /*
  *  call-seq:
- *     ary.reverse_each { |item| block }  -> ary
- *     ary.reverse_each                   -> Enumerator
+ *    array.reverse_each {|element| ... } -> self
+ *    array.reverse_each -> Enumerator
+ *
+ *  Iterates backwards over array elements.
+ *
+ *  When a block given, passes, in reverse order, each element to the block;
+ *  returns +self+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.reverse_each {|element|  puts "#{element.class} #{element}" }
+ *
+ *  Output:
+ *
+ *    Integer 2
+ *    String bar
+ *    Symbol foo
  *
- *  Same as Array#each, but traverses +self+ in reverse order.
+ *  Allows the array to be modified during iteration:
  *
- *     a = [ "a", "b", "c" ]
- *     a.reverse_each {|x| print x, " " }
+ *    a = [:foo, 'bar', 2]
+ *    a.reverse_each {|element| puts element; a.clear if element.to_s.start_with?('b') }
  *
- *  produces:
+ *  Output:
  *
- *     c b a
+ *    2
+ *    bar
+ *
+ *  When no block given, returns a new \Enumerator:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    e = a.reverse_each
+ *    e # => #<Enumerator: [:foo, "bar", 2]:reverse_each>
+ *    a1 = e.each {|element|  puts "#{element.class} #{element}" }
+ *
+ *  Output:
+ *
+ *    Integer 2
+ *    String bar
+ *    Symbol foo
+ *
+ *  Related: #each, #each_index.
  */
 
 static VALUE
@@ -1847,24 +2852,21 @@ rb_ary_reverse_each(VALUE ary)
     RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
     len = RARRAY_LEN(ary);
     while (len--) {
-	long nlen;
-	rb_yield(RARRAY_AREF(ary, len));
-	nlen = RARRAY_LEN(ary);
-	if (nlen < len) {
-	    len = nlen;
-	}
+        long nlen;
+        rb_yield(RARRAY_AREF(ary, len));
+        nlen = RARRAY_LEN(ary);
+        if (nlen < len) {
+            len = nlen;
+        }
     }
     return ary;
 }
 
 /*
  *  call-seq:
- *     ary.length -> int
+ *    array.length -> an_integer
  *
- *  Returns the number of elements in +self+. May be zero.
- *
- *     [ 1, 2, 3, 4, 5 ].length   #=> 5
- *     [].length                  #=> 0
+ *  Returns the count of elements in +self+.
  */
 
 static VALUE
@@ -1876,19 +2878,16 @@ rb_ary_length(VALUE ary)
 
 /*
  *  call-seq:
- *     ary.empty?   -> true or false
- *
- *  Returns +true+ if +self+ contains no elements.
+ *    array.empty?  -> true or false
  *
- *     [].empty?   #=> true
+ *  Returns +true+ if the count of elements in +self+ is zero,
+ *  +false+ otherwise.
  */
 
 static VALUE
 rb_ary_empty_p(VALUE ary)
 {
-    if (RARRAY_LEN(ary) == 0)
-	return Qtrue;
-    return Qfalse;
+    return RBOOL(RARRAY_LEN(ary) == 0);
 }
 
 VALUE
@@ -1896,15 +2895,18 @@ rb_ary_dup(VALUE ary)
 {
     long len = RARRAY_LEN(ary);
     VALUE dup = rb_ary_new2(len);
-    ary_memcpy(dup, 0, len, RARRAY_CONST_PTR(ary));
+    ary_memcpy(dup, 0, len, RARRAY_CONST_PTR_TRANSIENT(ary));
     ARY_SET_LEN(dup, len);
+
+    ary_verify(ary);
+    ary_verify(dup);
     return dup;
 }
 
 VALUE
 rb_ary_resurrect(VALUE ary)
 {
-    return rb_ary_new4(RARRAY_LEN(ary), RARRAY_CONST_PTR(ary));
+    return ary_make_partial(ary, rb_cArray, 0, RARRAY_LEN(ary));
 }
 
 extern VALUE rb_output_fs;
@@ -1921,15 +2923,15 @@ recursive_join(VALUE obj, VALUE argp, int recur)
     int *first = (int *)arg[3];
 
     if (recur) {
-	rb_raise(rb_eArgError, "recursive array join");
+        rb_raise(rb_eArgError, "recursive array join");
     }
     else {
-	ary_join_1(obj, ary, sep, 0, result, first);
+        ary_join_1(obj, ary, sep, 0, result, first);
     }
     return Qnil;
 }
 
-static void
+static long
 ary_join_0(VALUE ary, VALUE sep, long max, VALUE result)
 {
     long i;
@@ -1937,11 +2939,40 @@ ary_join_0(VALUE ary, VALUE sep, long max, VALUE result)
 
     if (max > 0) rb_enc_copy(result, RARRAY_AREF(ary, 0));
     for (i=0; i<max; i++) {
-	val = RARRAY_AREF(ary, i);
-	if (i > 0 && !NIL_P(sep))
-	    rb_str_buf_append(result, sep);
-	rb_str_buf_append(result, val);
-	if (OBJ_TAINTED(val)) OBJ_TAINT(result);
+        val = RARRAY_AREF(ary, i);
+        if (!RB_TYPE_P(val, T_STRING)) break;
+        if (i > 0 && !NIL_P(sep))
+            rb_str_buf_append(result, sep);
+        rb_str_buf_append(result, val);
+    }
+    return i;
+}
+
+static void
+ary_join_1_str(VALUE dst, VALUE src, int *first)
+{
+    rb_str_buf_append(dst, src);
+    if (*first) {
+        rb_enc_copy(dst, src);
+        *first = FALSE;
+    }
+}
+
+static void
+ary_join_1_ary(VALUE obj, VALUE ary, VALUE sep, VALUE result, VALUE val, int *first)
+{
+    if (val == ary) {
+        rb_raise(rb_eArgError, "recursive array join");
+    }
+    else {
+        VALUE args[4];
+
+        *first = FALSE;
+        args[0] = val;
+        args[1] = sep;
+        args[2] = result;
+        args[3] = (VALUE)first;
+        rb_exec_recursive(recursive_join, obj, (VALUE)args);
     }
 }
 
@@ -1951,50 +2982,25 @@ ary_join_1(VALUE obj, VALUE ary, VALUE sep, long i, VALUE result, int *first)
     VALUE val, tmp;
 
     for (; i<RARRAY_LEN(ary); i++) {
-	if (i > 0 && !NIL_P(sep))
-	    rb_str_buf_append(result, sep);
-
-	val = RARRAY_AREF(ary, i);
-	if (RB_TYPE_P(val, T_STRING)) {
-	  str_join:
-	    rb_str_buf_append(result, val);
-	    *first = FALSE;
-	}
-	else if (RB_TYPE_P(val, T_ARRAY)) {
-	    obj = val;
-	  ary_join:
-	    if (val == ary) {
-		rb_raise(rb_eArgError, "recursive array join");
-	    }
-	    else {
-		VALUE args[4];
-
-		args[0] = val;
-		args[1] = sep;
-		args[2] = result;
-		args[3] = (VALUE)first;
-		rb_exec_recursive(recursive_join, obj, (VALUE)args);
-	    }
-	}
-	else {
-	    tmp = rb_check_string_type(val);
-	    if (!NIL_P(tmp)) {
-		val = tmp;
-		goto str_join;
-	    }
-	    tmp = rb_check_convert_type(val, T_ARRAY, "Array", "to_ary");
-	    if (!NIL_P(tmp)) {
-		obj = val;
-		val = tmp;
-		goto ary_join;
-	    }
-	    val = rb_obj_as_string(val);
-	    if (*first) {
-		rb_enc_copy(result, val);
-		*first = FALSE;
-	    }
-	    goto str_join;
-	}
+        if (i > 0 && !NIL_P(sep))
+            rb_str_buf_append(result, sep);
+
+        val = RARRAY_AREF(ary, i);
+        if (RB_TYPE_P(val, T_STRING)) {
+            ary_join_1_str(result, val, first);
+        }
+        else if (RB_TYPE_P(val, T_ARRAY)) {
+            ary_join_1_ary(val, ary, sep, result, val, first);
+        }
+        else if (!NIL_P(tmp = rb_check_string_type(val))) {
+            ary_join_1_str(result, tmp, first);
+        }
+        else if (!NIL_P(tmp = rb_check_array_type(val))) {
+            ary_join_1_ary(val, ary, sep, result, tmp, first);
+        }
+        else {
+            ary_join_1_str(result, rb_obj_as_string(val), first);
+        }
     }
 }
 
@@ -2002,36 +3008,36 @@ VALUE
 rb_ary_join(VALUE ary, VALUE sep)
 {
     long len = 1, i;
-    int taint = FALSE;
     VALUE val, tmp, result;
 
     if (RARRAY_LEN(ary) == 0) return rb_usascii_str_new(0, 0);
-    if (OBJ_TAINTED(ary)) taint = TRUE;
 
     if (!NIL_P(sep)) {
-	StringValue(sep);
-	len += RSTRING_LEN(sep) * (RARRAY_LEN(ary) - 1);
+        StringValue(sep);
+        len += RSTRING_LEN(sep) * (RARRAY_LEN(ary) - 1);
     }
     for (i=0; i<RARRAY_LEN(ary); i++) {
-	val = RARRAY_AREF(ary, i);
-	tmp = rb_check_string_type(val);
-
-	if (NIL_P(tmp) || tmp != val) {
-	    int first;
-	    result = rb_str_buf_new(len + (RARRAY_LEN(ary)-i)*10);
-	    rb_enc_associate(result, rb_usascii_encoding());
-	    if (taint) OBJ_TAINT(result);
-	    ary_join_0(ary, sep, i, result);
-	    first = i == 0;
-	    ary_join_1(ary, ary, sep, i, result, &first);
-	    return result;
-	}
+        val = RARRAY_AREF(ary, i);
+        tmp = rb_check_string_type(val);
+
+        if (NIL_P(tmp) || tmp != val) {
+            int first;
+            long n = RARRAY_LEN(ary);
+            if (i > n) i = n;
+            result = rb_str_buf_new(len + (n-i)*10);
+            rb_enc_associate(result, rb_usascii_encoding());
+            i = ary_join_0(ary, sep, i, result);
+            first = i == 0;
+            ary_join_1(ary, ary, sep, i, result, &first);
+            return result;
+        }
 
-	len += RSTRING_LEN(tmp);
+        len += RSTRING_LEN(tmp);
     }
 
-    result = rb_str_buf_new(len);
-    if (taint) OBJ_TAINT(result);
+    result = rb_str_new(0, len);
+    rb_str_set_len(result, 0);
+
     ary_join_0(ary, sep, RARRAY_LEN(ary), result);
 
     return result;
@@ -2039,24 +3045,43 @@ rb_ary_join(VALUE ary, VALUE sep)
 
 /*
  *  call-seq:
- *     ary.join(separator=$,)    -> str
+ *    array.join ->new_string
+ *    array.join(separator = $,) -> new_string
+ *
+ *  Returns the new \String formed by joining the array elements after conversion.
+ *  For each element +element+:
+ *
+ *  - Uses <tt>element.to_s</tt> if +element+ is not a <tt>kind_of?(Array)</tt>.
+ *  - Uses recursive <tt>element.join(separator)</tt> if +element+ is a <tt>kind_of?(Array)</tt>.
+ *
+ *  With no argument, joins using the output field separator, <tt>$,</tt>:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    $, # => nil
+ *    a.join # => "foobar2"
  *
- *  Returns a string created by converting each element of the array to
- *  a string, separated by the given +separator+.
- *  If the +separator+ is +nil+, it uses current $,.
- *  If both the +separator+ and $, are nil, it uses empty string.
+ *  With \string argument +separator+, joins using that separator:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.join("\n") # => "foo\nbar\n2"
+ *
+ *  Joins recursively for nested Arrays:
+ *
+ *   a = [:foo, [:bar, [:baz, :bat]]]
+ *   a.join # => "foobarbazbat"
  *
- *     [ "a", "b", "c" ].join        #=> "abc"
- *     [ "a", "b", "c" ].join("-")   #=> "a-b-c"
  */
-
 static VALUE
 rb_ary_join_m(int argc, VALUE *argv, VALUE ary)
 {
     VALUE sep;
 
-    rb_scan_args(argc, argv, "01", &sep);
-    if (NIL_P(sep)) sep = rb_output_fs;
+    if (rb_check_arity(argc, 0, 1) == 0 || NIL_P(sep = argv[0])) {
+        sep = rb_output_fs;
+        if (!NIL_P(sep)) {
+            rb_category_warn(RB_WARN_CATEGORY_DEPRECATED, "$, is set to non-nil value");
+        }
+    }
 
     return rb_ary_join(ary, sep);
 }
@@ -2064,32 +3089,32 @@ rb_ary_join_m(int argc, VALUE *argv, VALUE ary)
 static VALUE
 inspect_ary(VALUE ary, VALUE dummy, int recur)
 {
-    int tainted = OBJ_TAINTED(ary);
     long i;
     VALUE s, str;
 
     if (recur) return rb_usascii_str_new_cstr("[...]");
     str = rb_str_buf_new2("[");
     for (i=0; i<RARRAY_LEN(ary); i++) {
-	s = rb_inspect(RARRAY_AREF(ary, i));
-	if (OBJ_TAINTED(s)) tainted = TRUE;
-	if (i > 0) rb_str_buf_cat2(str, ", ");
-	else rb_enc_copy(str, s);
-	rb_str_buf_append(str, s);
+        s = rb_inspect(RARRAY_AREF(ary, i));
+        if (i > 0) rb_str_buf_cat2(str, ", ");
+        else rb_enc_copy(str, s);
+        rb_str_buf_append(str, s);
     }
     rb_str_buf_cat2(str, "]");
-    if (tainted) OBJ_TAINT(str);
     return str;
 }
 
 /*
  *  call-seq:
- *     ary.inspect  -> string
- *     ary.to_s     -> string
+ *    array.inspect -> new_string
+ *
+ *  Returns the new \String formed by calling method <tt>#inspect</tt>
+ *  on each array element:
  *
- *  Creates a string representation of +self+.
+ *    a = [:foo, 'bar', 2]
+ *    a.inspect # => "[:foo, \"bar\", 2]"
  *
- *     [ "a", "b", "c" ].to_s     #=> "[\"a\", \"b\", \"c\"]"
+ *  Array#to_s is an alias for Array#inspect.
  */
 
 static VALUE
@@ -2107,58 +3132,88 @@ rb_ary_to_s(VALUE ary)
 
 /*
  *  call-seq:
- *     ary.to_a     -> ary
+ *    to_a -> self or new_array
  *
- *  Returns +self+.
+ *  When +self+ is an instance of \Array, returns +self+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.to_a # => [:foo, "bar", 2]
+ *
+ *  Otherwise, returns a new \Array containing the elements of +self+:
+ *
+ *    class MyArray < Array; end
+ *    a = MyArray.new(['foo', 'bar', 'two'])
+ *    a.instance_of?(Array) # => false
+ *    a.kind_of?(Array) # => true
+ *    a1 = a.to_a
+ *    a1 # => ["foo", "bar", "two"]
+ *    a1.class # => Array # Not MyArray
  *
- *  If called on a subclass of Array, converts the receiver to an Array object.
  */
 
 static VALUE
 rb_ary_to_a(VALUE ary)
 {
     if (rb_obj_class(ary) != rb_cArray) {
-	VALUE dup = rb_ary_new2(RARRAY_LEN(ary));
-	rb_ary_replace(dup, ary);
-	return dup;
+        VALUE dup = rb_ary_new2(RARRAY_LEN(ary));
+        rb_ary_replace(dup, ary);
+        return dup;
     }
     return ary;
 }
 
 /*
  *  call-seq:
- *     ary.to_h     -> hash
+ *    array.to_h -> new_hash
+ *    array.to_h {|item| ... } -> new_hash
+ *
+ *  Returns a new \Hash formed from +self+.
+ *
+ *  When a block is given, calls the block with each array element;
+ *  the block must return a 2-element \Array whose two elements
+ *  form a key-value pair in the returned \Hash:
+ *
+ *    a = ['foo', :bar, 1, [2, 3], {baz: 4}]
+ *    h = a.to_h {|item| [item, item] }
+ *    h # => {"foo"=>"foo", :bar=>:bar, 1=>1, [2, 3]=>[2, 3], {:baz=>4}=>{:baz=>4}}
+ *
+ *  When no block is given, +self+ must be an \Array of 2-element sub-arrays,
+ *  each sub-array is formed into a key-value pair in the new \Hash:
  *
- *  Returns the result of interpreting <i>ary</i> as an array of
- *  <tt>[key, value]</tt> pairs.
+ *    [].to_h # => {}
+ *    a = [['foo', 'zero'], ['bar', 'one'], ['baz', 'two']]
+ *    h = a.to_h
+ *    h # => {"foo"=>"zero", "bar"=>"one", "baz"=>"two"}
  *
- *     [[:foo, :bar], [1, 2]].to_h
- *       # => {:foo => :bar, 1 => 2}
  */
 
 static VALUE
 rb_ary_to_h(VALUE ary)
 {
     long i;
-    VALUE hash = rb_hash_new();
+    VALUE hash = rb_hash_new_with_size(RARRAY_LEN(ary));
+    int block_given = rb_block_given_p();
+
     for (i=0; i<RARRAY_LEN(ary); i++) {
-	VALUE key_value_pair = rb_check_array_type(rb_ary_elt(ary, i));
-	if (NIL_P(key_value_pair)) {
-	    rb_raise(rb_eTypeError, "wrong element type %s at %ld (expected array)",
-		rb_builtin_class_name(rb_ary_elt(ary, i)), i);
-	}
-	if (RARRAY_LEN(key_value_pair) != 2) {
-	    rb_raise(rb_eArgError, "wrong array length at %ld (expected 2, was %ld)",
-		i, RARRAY_LEN(key_value_pair));
-	}
-	rb_hash_aset(hash, RARRAY_AREF(key_value_pair, 0), RARRAY_AREF(key_value_pair, 1));
+        const VALUE e = rb_ary_elt(ary, i);
+        const VALUE elt = block_given ? rb_yield_force_blockarg(e) : e;
+        const VALUE key_value_pair = rb_check_array_type(elt);
+        if (NIL_P(key_value_pair)) {
+            rb_raise(rb_eTypeError, "wrong element type %"PRIsVALUE" at %ld (expected array)",
+                     rb_obj_class(elt), i);
+        }
+        if (RARRAY_LEN(key_value_pair) != 2) {
+            rb_raise(rb_eArgError, "wrong array length at %ld (expected 2, was %ld)",
+                i, RARRAY_LEN(key_value_pair));
+        }
+        rb_hash_aset(hash, RARRAY_AREF(key_value_pair, 0), RARRAY_AREF(key_value_pair, 1));
     }
     return hash;
 }
 
 /*
  *  call-seq:
- *     ary.to_ary -> ary
+ *    array.to_ary -> self
  *
  *  Returns +self+.
  */
@@ -2173,9 +3228,9 @@ static void
 ary_reverse(VALUE *p1, VALUE *p2)
 {
     while (p1 < p2) {
-	VALUE tmp = *p1;
-	*p1++ = *p2;
-	*p2-- = tmp;
+        VALUE tmp = *p1;
+        *p1++ = *p2;
+        *p2-- = tmp;
     }
 }
 
@@ -2187,23 +3242,23 @@ rb_ary_reverse(VALUE ary)
 
     rb_ary_modify(ary);
     if (len > 1) {
-	RARRAY_PTR_USE(ary, p1, {
-	    p2 = p1 + len - 1;	/* points last item */
-	    ary_reverse(p1, p2);
-	}); /* WB: no new reference */
+        RARRAY_PTR_USE_TRANSIENT(ary, p1, {
+            p2 = p1 + len - 1;	/* points last item */
+            ary_reverse(p1, p2);
+        }); /* WB: no new reference */
     }
     return ary;
 }
 
 /*
  *  call-seq:
- *     ary.reverse!   -> ary
+ *    array.reverse! -> self
+ *
+ *  Reverses +self+ in place:
  *
- *  Reverses +self+ in place.
+ *    a = ['foo', 'bar', 'two']
+ *    a.reverse! # => ["two", "bar", "foo"]
  *
- *     a = [ "a", "b", "c" ]
- *     a.reverse!       #=> ["c", "b", "a"]
- *     a                #=> ["c", "b", "a"]
  */
 
 static VALUE
@@ -2214,12 +3269,14 @@ rb_ary_reverse_bang(VALUE ary)
 
 /*
  *  call-seq:
- *     ary.reverse    -> new_ary
+ *    array.reverse -> new_array
  *
- *  Returns a new array containing +self+'s elements in reverse order.
+ *  Returns a new \Array with the elements of +self+ in reverse order:
+ *
+ *    a = ['foo', 'bar', 'two']
+ *    a1 = a.reverse
+ *    a1 # => ["two", "bar", "foo"]
  *
- *     [ "a", "b", "c" ].reverse   #=> ["c", "b", "a"]
- *     [ 1 ].reverse               #=> [1]
  */
 
 static VALUE
@@ -2229,9 +3286,9 @@ rb_ary_reverse_m(VALUE ary)
     VALUE dup = rb_ary_new2(len);
 
     if (len > 0) {
-	const VALUE *p1 = RARRAY_CONST_PTR(ary);
-	VALUE *p2 = (VALUE *)RARRAY_CONST_PTR(dup) + len - 1;
-	do *p2-- = *p1++; while (--len > 0);
+        const VALUE *p1 = RARRAY_CONST_PTR_TRANSIENT(ary);
+        VALUE *p2 = (VALUE *)RARRAY_CONST_PTR_TRANSIENT(dup) + len - 1;
+        do *p2-- = *p1++; while (--len > 0);
     }
     ARY_SET_LEN(dup, RARRAY_LEN(ary));
     return dup;
@@ -2243,73 +3300,143 @@ rotate_count(long cnt, long len)
     return (cnt < 0) ? (len - (~cnt % len) - 1) : (cnt % len);
 }
 
+static void
+ary_rotate_ptr(VALUE *ptr, long len, long cnt)
+{
+    if (cnt == 1) {
+        VALUE tmp = *ptr;
+        memmove(ptr, ptr + 1, sizeof(VALUE)*(len - 1));
+        *(ptr + len - 1) = tmp;
+    }
+    else if (cnt == len - 1) {
+        VALUE tmp = *(ptr + len - 1);
+        memmove(ptr + 1, ptr, sizeof(VALUE)*(len - 1));
+        *ptr = tmp;
+    }
+    else {
+        --len;
+        if (cnt < len) ary_reverse(ptr + cnt, ptr + len);
+        if (--cnt > 0) ary_reverse(ptr, ptr + cnt);
+        if (len > 0) ary_reverse(ptr, ptr + len);
+    }
+}
+
 VALUE
 rb_ary_rotate(VALUE ary, long cnt)
 {
     rb_ary_modify(ary);
 
     if (cnt != 0) {
-	VALUE *ptr = RARRAY_PTR(ary);
-	long len = RARRAY_LEN(ary);
-
-	if (len > 0 && (cnt = rotate_count(cnt, len)) > 0) {
-	    --len;
-	    if (cnt < len) ary_reverse(ptr + cnt, ptr + len);
-	    if (--cnt > 0) ary_reverse(ptr, ptr + cnt);
-	    if (len > 0) ary_reverse(ptr, ptr + len);
-	    return ary;
-	}
+        long len = RARRAY_LEN(ary);
+        if (len > 1 && (cnt = rotate_count(cnt, len)) > 0) {
+            RARRAY_PTR_USE_TRANSIENT(ary, ptr, ary_rotate_ptr(ptr, len, cnt));
+            return ary;
+        }
     }
-
     return Qnil;
 }
 
 /*
  *  call-seq:
- *     ary.rotate!(count=1)   -> ary
+ *    array.rotate! -> self
+ *    array.rotate!(count) -> self
  *
- *  Rotates +self+ in place so that the element at +count+ comes first, and
- *  returns +self+.
+ *  Rotates +self+ in place by moving elements from one end to the other; returns +self+.
+ *
+ *  When no argument given, rotates the first element to the last position:
+ *
+ *    a = [:foo, 'bar', 2, 'bar']
+ *    a.rotate! # => ["bar", 2, "bar", :foo]
+ *
+ *  When given a non-negative \Integer +count+,
+ *  rotates +count+ elements from the beginning to the end:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.rotate!(2)
+ *    a # => [2, :foo, "bar"]
+ *
+ *  If +count+ is large, uses <tt>count % array.size</tt> as the count:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.rotate!(20)
+ *    a # => [2, :foo, "bar"]
  *
- *  If +count+ is negative then it rotates in the opposite direction, starting
- *  from the end of the array where +-1+ is the last element.
+ *  If +count+ is zero, returns +self+ unmodified:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.rotate!(0)
+ *    a # => [:foo, "bar", 2]
+ *
+ *  When given a negative Integer +count+, rotates in the opposite direction,
+ *  from end to beginning:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.rotate!(-2)
+ *    a # => ["bar", 2, :foo]
+ *
+ *  If +count+ is small (far from zero), uses <tt>count % array.size</tt> as the count:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.rotate!(-5)
+ *    a # => ["bar", 2, :foo]
  *
- *     a = [ "a", "b", "c", "d" ]
- *     a.rotate!        #=> ["b", "c", "d", "a"]
- *     a                #=> ["b", "c", "d", "a"]
- *     a.rotate!(2)     #=> ["d", "a", "b", "c"]
- *     a.rotate!(-3)    #=> ["a", "b", "c", "d"]
  */
 
 static VALUE
 rb_ary_rotate_bang(int argc, VALUE *argv, VALUE ary)
 {
-    long n = 1;
-
-    switch (argc) {
-      case 1: n = NUM2LONG(argv[0]);
-      case 0: break;
-      default: rb_scan_args(argc, argv, "01", NULL);
-    }
+    long n = (rb_check_arity(argc, 0, 1) ? NUM2LONG(argv[0]) : 1);
     rb_ary_rotate(ary, n);
     return ary;
 }
 
 /*
  *  call-seq:
- *     ary.rotate(count=1)    -> new_ary
+ *    array.rotate -> new_array
+ *    array.rotate(count) -> new_array
+ *
+ *  Returns a new \Array formed from +self+ with elements
+ *  rotated from one end to the other.
+ *
+ *  When no argument given, returns a new \Array that is like +self+,
+ *  except that the first element has been rotated to the last position:
+ *
+ *    a = [:foo, 'bar', 2, 'bar']
+ *    a1 = a.rotate
+ *    a1 # => ["bar", 2, "bar", :foo]
+ *
+ *  When given a non-negative \Integer +count+,
+ *  returns a new \Array with +count+ elements rotated from the beginning to the end:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a1 = a.rotate(2)
+ *    a1 # => [2, :foo, "bar"]
+ *
+ *  If +count+ is large, uses <tt>count % array.size</tt> as the count:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a1 = a.rotate(20)
+ *    a1 # => [2, :foo, "bar"]
  *
- *  Returns a new array by rotating +self+ so that the element at +count+ is
- *  the first element of the new array.
+ *  If +count+ is zero, returns a copy of +self+, unmodified:
  *
- *  If +count+ is negative then it rotates in the opposite direction, starting
- *  from the end of +self+ where +-1+ is the last element.
+ *    a = [:foo, 'bar', 2]
+ *    a1 = a.rotate(0)
+ *    a1 # => [:foo, "bar", 2]
+ *
+ *  When given a negative \Integer +count+, rotates in the opposite direction,
+ *  from end to beginning:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a1 = a.rotate(-2)
+ *    a1 # => ["bar", 2, :foo]
+ *
+ *  If +count+ is small (far from zero), uses <tt>count % array.size</tt> as the count:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a1 = a.rotate(-5)
+ *    a1 # => ["bar", 2, :foo]
  *
- *     a = [ "a", "b", "c", "d" ]
- *     a.rotate         #=> ["b", "c", "d", "a"]
- *     a                #=> ["a", "b", "c", "d"]
- *     a.rotate(2)      #=> ["c", "d", "a", "b"]
- *     a.rotate(-3)     #=> ["b", "c", "d", "a"]
  */
 
 static VALUE
@@ -2317,22 +3444,17 @@ rb_ary_rotate_m(int argc, VALUE *argv, VALUE ary)
 {
     VALUE rotated;
     const VALUE *ptr;
-    long len, cnt = 1;
-
-    switch (argc) {
-      case 1: cnt = NUM2LONG(argv[0]);
-      case 0: break;
-      default: rb_scan_args(argc, argv, "01", NULL);
-    }
+    long len;
+    long cnt = (rb_check_arity(argc, 0, 1) ? NUM2LONG(argv[0]) : 1);
 
     len = RARRAY_LEN(ary);
     rotated = rb_ary_new2(len);
     if (len > 0) {
-	cnt = rotate_count(cnt, len);
-	ptr = RARRAY_CONST_PTR(ary);
-	len -= cnt;
-	ary_memcpy(rotated, 0, len, ptr + cnt);
-	ary_memcpy(rotated, len, cnt, ptr);
+        cnt = rotate_count(cnt, len);
+        ptr = RARRAY_CONST_PTR_TRANSIENT(ary);
+        len -= cnt;
+        ary_memcpy(rotated, 0, len, ptr + cnt);
+        ary_memcpy(rotated, len, cnt, ptr);
     }
     ARY_SET_LEN(rotated, RARRAY_LEN(ary));
     return rotated;
@@ -2340,46 +3462,41 @@ rb_ary_rotate_m(int argc, VALUE *argv, VALUE ary)
 
 struct ary_sort_data {
     VALUE ary;
-    int opt_methods;
-    int opt_inited;
+    VALUE receiver;
 };
 
-enum {
-    sort_opt_Fixnum,
-    sort_opt_String,
-    sort_optimizable_count
-};
-
-#define STRING_P(s) (RB_TYPE_P((s), T_STRING) && CLASS_OF(s) == rb_cString)
-
-#define SORT_OPTIMIZABLE_BIT(type) (1U << TOKEN_PASTE(sort_opt_,type))
-#define SORT_OPTIMIZABLE(data, type) \
-    (((data)->opt_inited & SORT_OPTIMIZABLE_BIT(type)) ? \
-     ((data)->opt_methods & SORT_OPTIMIZABLE_BIT(type)) : \
-     (((data)->opt_inited |= SORT_OPTIMIZABLE_BIT(type)), \
-      rb_method_basic_definition_p(TOKEN_PASTE(rb_c,type), id_cmp) && \
-      ((data)->opt_methods |= SORT_OPTIMIZABLE_BIT(type))))
-
 static VALUE
 sort_reentered(VALUE ary)
 {
     if (RBASIC(ary)->klass) {
-	rb_raise(rb_eRuntimeError, "sort reentered");
+        rb_raise(rb_eRuntimeError, "sort reentered");
     }
     return Qnil;
 }
 
+static void
+sort_returned(struct ary_sort_data *data)
+{
+    if (rb_obj_frozen_p(data->receiver)) {
+        rb_raise(rb_eFrozenError, "array frozen during sort");
+    }
+    sort_reentered(data->ary);
+}
+
 static int
 sort_1(const void *ap, const void *bp, void *dummy)
 {
     struct ary_sort_data *data = dummy;
     VALUE retval = sort_reentered(data->ary);
     VALUE a = *(const VALUE *)ap, b = *(const VALUE *)bp;
+    VALUE args[2];
     int n;
 
-    retval = rb_yield_values(2, a, b);
+    args[0] = a;
+    args[1] = b;
+    retval = rb_yield_values2(2, args);
     n = rb_cmpint(retval, a, b);
-    sort_reentered(data->ary);
+    sort_returned(data);
     return n;
 }
 
@@ -2391,41 +3508,64 @@ sort_2(const void *ap, const void *bp, void *dummy)
     VALUE a = *(const VALUE *)ap, b = *(const VALUE *)bp;
     int n;
 
-    if (FIXNUM_P(a) && FIXNUM_P(b) && SORT_OPTIMIZABLE(data, Fixnum)) {
-	if ((long)a > (long)b) return 1;
-	if ((long)a < (long)b) return -1;
-	return 0;
+    if (FIXNUM_P(a) && FIXNUM_P(b) && CMP_OPTIMIZABLE(INTEGER)) {
+        if ((long)a > (long)b) return 1;
+        if ((long)a < (long)b) return -1;
+        return 0;
+    }
+    if (STRING_P(a) && STRING_P(b) && CMP_OPTIMIZABLE(STRING)) {
+        return rb_str_cmp(a, b);
     }
-    if (STRING_P(a) && STRING_P(b) && SORT_OPTIMIZABLE(data, String)) {
-	return rb_str_cmp(a, b);
+    if (RB_FLOAT_TYPE_P(a) && CMP_OPTIMIZABLE(FLOAT)) {
+        return rb_float_cmp(a, b);
     }
 
     retval = rb_funcallv(a, id_cmp, 1, &b);
     n = rb_cmpint(retval, a, b);
-    sort_reentered(data->ary);
+    sort_returned(data);
 
     return n;
 }
 
 /*
  *  call-seq:
- *     ary.sort!                   -> ary
- *     ary.sort! { |a, b| block }  -> ary
+ *    array.sort! -> self
+ *    array.sort! {|a, b| ... } -> self
+ *
+ *  Returns +self+ with its elements sorted in place.
  *
- *  Sorts +self+ in place.
+ *  With no block, compares elements using operator <tt><=></tt>
+ *  (see Comparable):
  *
- *  Comparisons for the sort will be done using the <code><=></code> operator
- *  or using an optional code block.
+ *    a = 'abcde'.split('').shuffle
+ *    a # => ["e", "b", "d", "a", "c"]
+ *    a.sort!
+ *    a # => ["a", "b", "c", "d", "e"]
  *
- *  The block must implement a comparison between +a+ and +b+, and return
- *  +-1+, when +a+ follows +b+, +0+ when +a+ and +b+ are equivalent, or ++1+
- *  if +b+ follows +a+.
+ *  With a block, calls the block with each element pair;
+ *  for each element pair +a+ and +b+, the block should return an integer:
  *
- *  See also Enumerable#sort_by.
+ *  - Negative when +b+ is to follow +a+.
+ *  - Zero when +a+ and +b+ are equivalent.
+ *  - Positive when +a+ is to follow +b+.
+ *
+ *  Example:
+ *
+ *    a = 'abcde'.split('').shuffle
+ *    a # => ["e", "b", "d", "a", "c"]
+ *    a.sort! {|a, b| a <=> b }
+ *    a # => ["a", "b", "c", "d", "e"]
+ *    a.sort! {|a, b| b <=> a }
+ *    a # => ["e", "d", "c", "b", "a"]
+ *
+ *  When the block returns zero, the order for +a+ and +b+ is indeterminate,
+ *  and may be unstable:
+ *
+ *    a = 'abcde'.split('').shuffle
+ *    a # => ["e", "b", "d", "a", "c"]
+ *    a.sort! {|a, b| 0 }
+ *    a # => ["d", "e", "c", "a", "b"]
  *
- *     a = [ "d", "a", "e", "c", "b" ]
- *     a.sort!                    #=> ["a", "b", "c", "d", "e"]
- *     a.sort! { |x,y| y <=> x }  #=> ["e", "d", "c", "b", "a"]
  */
 
 VALUE
@@ -2434,25 +3574,23 @@ rb_ary_sort_bang(VALUE ary)
     rb_ary_modify(ary);
     assert(!ARY_SHARED_P(ary));
     if (RARRAY_LEN(ary) > 1) {
-	VALUE tmp = ary_make_substitution(ary); /* only ary refers tmp */
-	struct ary_sort_data data;
-	long len = RARRAY_LEN(ary);
-
-	RBASIC_CLEAR_CLASS(tmp);
-	data.ary = tmp;
-	data.opt_methods = 0;
-	data.opt_inited = 0;
-	RARRAY_PTR_USE(tmp, ptr, {
-	    ruby_qsort(ptr, len, sizeof(VALUE),
-		       rb_block_given_p()?sort_1:sort_2, &data);
-	}); /* WB: no new reference */
-	rb_ary_modify(ary);
+        VALUE tmp = ary_make_substitution(ary); /* only ary refers tmp */
+        struct ary_sort_data data;
+        long len = RARRAY_LEN(ary);
+        RBASIC_CLEAR_CLASS(tmp);
+        data.ary = tmp;
+        data.receiver = ary;
+        RARRAY_PTR_USE(tmp, ptr, {
+            ruby_qsort(ptr, len, sizeof(VALUE),
+                       rb_block_given_p()?sort_1:sort_2, &data);
+        }); /* WB: no new reference */
+        rb_ary_modify(ary);
         if (ARY_EMBED_P(tmp)) {
             if (ARY_SHARED_P(ary)) { /* ary might be destructively operated in the given block */
                 rb_ary_unshare(ary);
+                FL_SET_EMBED(ary);
             }
-            FL_SET_EMBED(ary);
-	    ary_memcpy(ary, 0, ARY_EMBED_LEN(tmp), ARY_EMBED_PTR(tmp));
+            ary_memcpy(ary, 0, ARY_EMBED_LEN(tmp), ARY_EMBED_PTR(tmp));
             ARY_SET_LEN(ary, ARY_EMBED_LEN(tmp));
         }
         else {
@@ -2470,44 +3608,65 @@ rb_ary_sort_bang(VALUE ary)
                     rb_ary_unshare(ary);
                 }
                 else {
-		    ruby_sized_xfree((void *)ARY_HEAP_PTR(ary), ARY_HEAP_SIZE(ary));
+                    ary_heap_free(ary);
                 }
-                ARY_SET_PTR(ary, RARRAY_CONST_PTR(tmp));
+                ARY_SET_PTR(ary, ARY_HEAP_PTR(tmp));
                 ARY_SET_HEAP_LEN(ary, len);
-                ARY_SET_CAPA(ary, RARRAY_LEN(tmp));
+                ARY_SET_CAPA(ary, ARY_HEAP_LEN(tmp));
             }
             /* tmp was lost ownership for the ptr */
             FL_UNSET(tmp, FL_FREEZE);
             FL_SET_EMBED(tmp);
             ARY_SET_EMBED_LEN(tmp, 0);
             FL_SET(tmp, FL_FREEZE);
-	}
+        }
         /* tmp will be GC'ed. */
         RBASIC_SET_CLASS_RAW(tmp, rb_cArray); /* rb_cArray must be marked */
     }
+    ary_verify(ary);
     return ary;
 }
 
 /*
  *  call-seq:
- *     ary.sort                   -> new_ary
- *     ary.sort { |a, b| block }  -> new_ary
+ *    array.sort -> new_array
+ *    array.sort {|a, b| ... } -> new_array
+ *
+ *  Returns a new \Array whose elements are those from +self+, sorted.
  *
- *  Returns a new array created by sorting +self+.
+ *  With no block, compares elements using operator <tt><=></tt>
+ *  (see Comparable):
  *
- *  Comparisons for the sort will be done using the <code><=></code> operator
- *  or using an optional code block.
+ *    a = 'abcde'.split('').shuffle
+ *    a # => ["e", "b", "d", "a", "c"]
+ *    a1 = a.sort
+ *    a1 # => ["a", "b", "c", "d", "e"]
  *
- *  The block must implement a comparison between +a+ and +b+, and return
- *  +-1+, when +a+ follows +b+, +0+ when +a+ and +b+ are equivalent, or ++1+
- *  if +b+ follows +a+.
+ *  With a block, calls the block with each element pair;
+ *  for each element pair +a+ and +b+, the block should return an integer:
  *
+ *  - Negative when +b+ is to follow +a+.
+ *  - Zero when +a+ and +b+ are equivalent.
+ *  - Positive when +a+ is to follow +b+.
  *
- *  See also Enumerable#sort_by.
+ *  Example:
  *
- *     a = [ "d", "a", "e", "c", "b" ]
- *     a.sort                    #=> ["a", "b", "c", "d", "e"]
- *     a.sort { |x,y| y <=> x }  #=> ["e", "d", "c", "b", "a"]
+ *    a = 'abcde'.split('').shuffle
+ *    a # => ["e", "b", "d", "a", "c"]
+ *    a1 = a.sort {|a, b| a <=> b }
+ *    a1 # => ["a", "b", "c", "d", "e"]
+ *    a2 = a.sort {|a, b| b <=> a }
+ *    a2 # => ["e", "d", "c", "b", "a"]
+ *
+ *  When the block returns zero, the order for +a+ and +b+ is indeterminate,
+ *  and may be unstable:
+ *
+ *    a = 'abcde'.split('').shuffle
+ *    a # => ["e", "b", "d", "a", "c"]
+ *    a1 = a.sort {|a, b| 0 }
+ *    a1 # =>  ["c", "e", "b", "d", "a"]
+ *
+ *  Related: Enumerable#sort_by.
  */
 
 VALUE
@@ -2518,105 +3677,83 @@ rb_ary_sort(VALUE ary)
     return ary;
 }
 
+static VALUE rb_ary_bsearch_index(VALUE ary);
+
 /*
  *  call-seq:
- *     ary.bsearch {|x| block }  -> elem
- *
- *  By using binary search, finds a value from this array which meets
- *  the given condition in O(log n) where n is the size of the array.
- *
- *  You can use this method in two use cases: a find-minimum mode and
- *  a find-any mode.  In either case, the elements of the array must be
- *  monotone (or sorted) with respect to the block.
- *
- *  In find-minimum mode (this is a good choice for typical use case),
- *  the block must return true or false, and there must be an index i
- *  (0 <= i <= ary.size) so that:
- *
- *  - the block returns false for any element whose index is less than
- *    i, and
- *  - the block returns true for any element whose index is greater
- *    than or equal to i.
- *
- *  This method returns the i-th element.  If i is equal to ary.size,
- *  it returns nil.
- *
- *     ary = [0, 4, 7, 10, 12]
- *     ary.bsearch {|x| x >=   4 } #=> 4
- *     ary.bsearch {|x| x >=   6 } #=> 7
- *     ary.bsearch {|x| x >=  -1 } #=> 0
- *     ary.bsearch {|x| x >= 100 } #=> nil
- *
- *  In find-any mode (this behaves like libc's bsearch(3)), the block
- *  must return a number, and there must be two indices i and j
- *  (0 <= i <= j <= ary.size) so that:
- *
- *  - the block returns a positive number for ary[k] if 0 <= k < i,
- *  - the block returns zero for ary[k] if i <= k < j, and
- *  - the block returns a negative number for ary[k] if
- *    j <= k < ary.size.
- *
- *  Under this condition, this method returns any element whose index
- *  is within i...j.  If i is equal to j (i.e., there is no element
- *  that satisfies the block), this method returns nil.
- *
- *     ary = [0, 4, 7, 10, 12]
- *     # try to find v such that 4 <= v < 8
- *     ary.bsearch {|x| 1 - x / 4 } #=> 4 or 7
- *     # try to find v such that 8 <= v < 10
- *     ary.bsearch {|x| 4 - x / 2 } #=> nil
- *
- *  You must not mix the two modes at a time; the block must always
- *  return either true/false, or always return a number.  It is
- *  undefined which value is actually picked up at each iteration.
+ *    array.bsearch {|element| ... } -> object
+ *    array.bsearch -> new_enumerator
+ *
+ *  Returns an element from +self+ selected by a binary search.
+ *
+ *  See {Binary Searching}[rdoc-ref:bsearch.rdoc].
  */
 
 static VALUE
 rb_ary_bsearch(VALUE ary)
 {
+    VALUE index_result = rb_ary_bsearch_index(ary);
+
+    if (FIXNUM_P(index_result)) {
+        return rb_ary_entry(ary, FIX2LONG(index_result));
+    }
+    return index_result;
+}
+
+/*
+ *  call-seq:
+ *    array.bsearch_index {|element| ... } -> integer or nil
+ *    array.bsearch_index -> new_enumerator
+ *
+ *  Searches +self+ as described at method #bsearch,
+ *  but returns the _index_ of the found element instead of the element itself.
+ */
+
+static VALUE
+rb_ary_bsearch_index(VALUE ary)
+{
     long low = 0, high = RARRAY_LEN(ary), mid;
     int smaller = 0, satisfied = 0;
     VALUE v, val;
 
     RETURN_ENUMERATOR(ary, 0, 0);
     while (low < high) {
-	mid = low + ((high - low) / 2);
-	val = rb_ary_entry(ary, mid);
-	v = rb_yield(val);
-	if (FIXNUM_P(v)) {
-	    if (FIX2INT(v) == 0) return val;
-	    smaller = FIX2INT(v) < 0;
-	}
-	else if (v == Qtrue) {
-	    satisfied = 1;
-	    smaller = 1;
-	}
-	else if (v == Qfalse || v == Qnil) {
-	    smaller = 0;
-	}
-	else if (rb_obj_is_kind_of(v, rb_cNumeric)) {
-	    const VALUE zero = INT2FIX(0);
-	    switch (rb_cmpint(rb_funcallv(v, id_cmp, 1, &zero), v, INT2FIX(0))) {
-		case 0: return val;
-		case 1: smaller = 1; break;
-		case -1: smaller = 0;
-	    }
-	}
-	else {
-	    rb_raise(rb_eTypeError, "wrong argument type %s"
-		" (must be numeric, true, false or nil)",
-		rb_obj_classname(v));
-	}
-	if (smaller) {
-	    high = mid;
-	}
-	else {
-	    low = mid + 1;
-	}
-    }
-    if (low == RARRAY_LEN(ary)) return Qnil;
+        mid = low + ((high - low) / 2);
+        val = rb_ary_entry(ary, mid);
+        v = rb_yield(val);
+        if (FIXNUM_P(v)) {
+            if (v == INT2FIX(0)) return INT2FIX(mid);
+            smaller = (SIGNED_VALUE)v < 0; /* Fixnum preserves its sign-bit */
+        }
+        else if (v == Qtrue) {
+            satisfied = 1;
+            smaller = 1;
+        }
+        else if (!RTEST(v)) {
+            smaller = 0;
+        }
+        else if (rb_obj_is_kind_of(v, rb_cNumeric)) {
+            const VALUE zero = INT2FIX(0);
+            switch (rb_cmpint(rb_funcallv(v, id_cmp, 1, &zero), v, zero)) {
+              case 0: return INT2FIX(mid);
+              case 1: smaller = 0; break;
+              case -1: smaller = 1;
+            }
+        }
+        else {
+            rb_raise(rb_eTypeError, "wrong argument type %"PRIsVALUE
+                     " (must be numeric, true, false or nil)",
+                     rb_obj_class(v));
+        }
+        if (smaller) {
+            high = mid;
+        }
+        else {
+            low = mid + 1;
+        }
+    }
     if (!satisfied) return Qnil;
-    return rb_ary_entry(ary, low);
+    return INT2FIX(low);
 }
 
 
@@ -2628,13 +3765,27 @@ sort_by_i(RB_BLOCK_CALL_FUNC_ARGLIST(i, dummy))
 
 /*
  *  call-seq:
- *     ary.sort_by! { |obj| block }    -> ary
- *     ary.sort_by!                    -> Enumerator
+ *    array.sort_by! {|element| ... } -> self
+ *    array.sort_by! -> new_enumerator
+ *
+ *  Sorts the elements of +self+ in place,
+ *  using an ordering determined by the block; returns self.
+ *
+ *  Calls the block with each successive element;
+ *  sorts elements based on the values returned from the block.
  *
- *  Sorts +self+ in place using a set of keys generated by mapping the
- *  values in +self+ through the given block.
+ *  For duplicates returned by the block, the ordering is indeterminate, and may be unstable.
  *
- *  If no block is given, an Enumerator is returned instead.
+ *  This example sorts strings based on their sizes:
+ *
+ *    a = ['aaaa', 'bbb', 'cc', 'd']
+ *    a.sort_by! {|element| element.size }
+ *    a # => ["d", "cc", "bbb", "aaaa"]
+ *
+ *  Returns a new \Enumerator if no block given:
+ *
+ *    a = ['aaaa', 'bbb', 'cc', 'd']
+ *    a.sort_by! # => #<Enumerator: ["aaaa", "bbb", "cc", "d"]:sort_by!>
  *
  */
 
@@ -2653,23 +3804,22 @@ rb_ary_sort_by_bang(VALUE ary)
 
 /*
  *  call-seq:
- *     ary.collect { |item| block }  -> new_ary
- *     ary.map     { |item| block }  -> new_ary
- *     ary.collect                   -> Enumerator
- *     ary.map                       -> Enumerator
- *
- *  Invokes the given block once for each element of +self+.
+ *    array.map {|element| ... } -> new_array
+ *    array.map -> new_enumerator
  *
- *  Creates a new array containing the values returned by the block.
+ *  Calls the block, if given, with each element of +self+;
+ *  returns a new \Array whose elements are the return values from the block:
  *
- *  See also Enumerable#collect.
+ *    a = [:foo, 'bar', 2]
+ *    a1 = a.map {|element| element.class }
+ *    a1 # => [Symbol, String, Integer]
  *
- *  If no block is given, an Enumerator is returned instead.
+ *  Returns a new \Enumerator if no block given:
+ *    a = [:foo, 'bar', 2]
+ *    a1 = a.map
+ *    a1 # => #<Enumerator: [:foo, "bar", 2]:map>
  *
- *     a = [ "a", "b", "c", "d" ]
- *     a.collect { |x| x + "!" }        #=> ["a!", "b!", "c!", "d!"]
- *     a.map.with_index{ |x, i| x * i } #=> ["", "b", "cc", "ddd"]
- *     a                                #=> ["a", "b", "c", "d"]
+ *  Array#collect is an alias for Array#map.
  */
 
 static VALUE
@@ -2681,7 +3831,7 @@ rb_ary_collect(VALUE ary)
     RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
     collect = rb_ary_new2(RARRAY_LEN(ary));
     for (i = 0; i < RARRAY_LEN(ary); i++) {
-	rb_ary_push(collect, rb_yield(RARRAY_AREF(ary, i)));
+        rb_ary_push(collect, rb_yield(RARRAY_AREF(ary, i)));
     }
     return collect;
 }
@@ -2689,23 +3839,22 @@ rb_ary_collect(VALUE ary)
 
 /*
  *  call-seq:
- *     ary.collect! {|item| block }   -> ary
- *     ary.map!     {|item| block }   -> ary
- *     ary.collect!                   -> Enumerator
- *     ary.map!                       -> Enumerator
+ *    array.map! {|element| ... } -> self
+ *    array.map! -> new_enumerator
  *
- *  Invokes the given block once for each element of +self+, replacing the
- *  element with the value returned by the block.
+ *  Calls the block, if given, with each element;
+ *  replaces the element with the block's return value:
  *
- *  See also Enumerable#collect.
+ *    a = [:foo, 'bar', 2]
+ *    a.map! { |element| element.class } # => [Symbol, String, Integer]
  *
- *  If no block is given, an Enumerator is returned instead.
+ *  Returns a new \Enumerator if no block given:
  *
- *     a = [ "a", "b", "c", "d" ]
- *     a.map! {|x| x + "!" }
- *     a #=>  [ "a!", "b!", "c!", "d!" ]
- *     a.collect!.with_index {|x, i| x[0...i] }
- *     a #=>  ["", "b", "c!", "d!"]
+ *    a = [:foo, 'bar', 2]
+ *    a1 = a.map!
+ *    a1 # => #<Enumerator: [:foo, "bar", 2]:map!>
+ *
+ *  Array#collect! is an alias for Array#map!.
  */
 
 static VALUE
@@ -2716,78 +3865,140 @@ rb_ary_collect_bang(VALUE ary)
     RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
     rb_ary_modify(ary);
     for (i = 0; i < RARRAY_LEN(ary); i++) {
-	rb_ary_store(ary, i, rb_yield(RARRAY_AREF(ary, i)));
+        rb_ary_store(ary, i, rb_yield(RARRAY_AREF(ary, i)));
     }
     return ary;
 }
 
 VALUE
-rb_get_values_at(VALUE obj, long olen, int argc, VALUE *argv, VALUE (*func) (VALUE, long))
+rb_get_values_at(VALUE obj, long olen, int argc, const VALUE *argv, VALUE (*func) (VALUE, long))
 {
     VALUE result = rb_ary_new2(argc);
     long beg, len, i, j;
 
     for (i=0; i<argc; i++) {
-	if (FIXNUM_P(argv[i])) {
-	    rb_ary_push(result, (*func)(obj, FIX2LONG(argv[i])));
-	    continue;
-	}
-	/* check if idx is Range */
-	if (rb_range_beg_len(argv[i], &beg, &len, olen, 1)) {
-	    long end = olen < beg+len ? olen : beg+len;
-	    for (j = beg; j < end; j++) {
-		rb_ary_push(result, (*func)(obj, j));
-	    }
-	    if (beg + len > j)
-		rb_ary_resize(result, RARRAY_LEN(result) + (beg + len) - j);
-	    continue;
-	}
-	rb_ary_push(result, (*func)(obj, NUM2LONG(argv[i])));
+        if (FIXNUM_P(argv[i])) {
+            rb_ary_push(result, (*func)(obj, FIX2LONG(argv[i])));
+            continue;
+        }
+        /* check if idx is Range */
+        if (rb_range_beg_len(argv[i], &beg, &len, olen, 1)) {
+            long end = olen < beg+len ? olen : beg+len;
+            for (j = beg; j < end; j++) {
+                rb_ary_push(result, (*func)(obj, j));
+            }
+            if (beg + len > j)
+                rb_ary_resize(result, RARRAY_LEN(result) + (beg + len) - j);
+            continue;
+        }
+        rb_ary_push(result, (*func)(obj, NUM2LONG(argv[i])));
     }
     return result;
 }
 
+static VALUE
+append_values_at_single(VALUE result, VALUE ary, long olen, VALUE idx)
+{
+    long beg, len;
+    if (FIXNUM_P(idx)) {
+        beg = FIX2LONG(idx);
+    }
+    /* check if idx is Range */
+    else if (rb_range_beg_len(idx, &beg, &len, olen, 1)) {
+        if (len > 0) {
+            const VALUE *const src = RARRAY_CONST_PTR_TRANSIENT(ary);
+            const long end = beg + len;
+            const long prevlen = RARRAY_LEN(result);
+            if (beg < olen) {
+                rb_ary_cat(result, src + beg, end > olen ? olen-beg : len);
+            }
+            if (end > olen) {
+                rb_ary_store(result, prevlen + len - 1, Qnil);
+            }
+        }
+        return result;
+    }
+    else {
+        beg = NUM2LONG(idx);
+    }
+    return rb_ary_push(result, rb_ary_entry(ary, beg));
+}
+
 /*
  *  call-seq:
- *     ary.values_at(selector, ...)  -> new_ary
+ *    array.values_at(*indexes) -> new_array
+ *
+ *  Returns a new \Array whose elements are the elements
+ *  of +self+ at the given \Integer or \Range +indexes+.
+ *
+ *  For each positive +index+, returns the element at offset +index+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.values_at(0, 2) # => [:foo, 2]
+ *    a.values_at(0..1) # => [:foo, "bar"]
+ *
+ *  The given +indexes+ may be in any order, and may repeat:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.values_at(2, 0, 1, 0, 2) # => [2, :foo, "bar", :foo, 2]
+ *    a.values_at(1, 0..2) # => ["bar", :foo, "bar", 2]
+ *
+ *  Assigns +nil+ for an +index+ that is too large:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.values_at(0, 3, 1, 3) # => [:foo, nil, "bar", nil]
+ *
+ *  Returns a new empty \Array if no arguments given.
+ *
+ *  For each negative +index+, counts backward from the end of the array:
  *
- *  Returns an array containing the elements in +self+ corresponding to the
- *  given +selector+(s).
+ *    a = [:foo, 'bar', 2]
+ *    a.values_at(-1, -3) # => [2, :foo]
  *
- *  The selectors may be either integer indices or ranges.
+ *  Assigns +nil+ for an +index+ that is too small:
  *
- *  See also Array#select.
+ *    a = [:foo, 'bar', 2]
+ *    a.values_at(0, -5, 1, -6, 2) # => [:foo, nil, "bar", nil, 2]
+ *
+ *  The given +indexes+ may have a mixture of signs:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.values_at(0, -2, 1, -1) # => [:foo, "bar", "bar", 2]
  *
- *     a = %w{ a b c d e f }
- *     a.values_at(1, 3, 5)          # => ["b", "d", "f"]
- *     a.values_at(1, 3, 5, 7)       # => ["b", "d", "f", nil]
- *     a.values_at(-1, -2, -2, -7)   # => ["f", "e", "e", nil]
- *     a.values_at(4..6, 3...6)      # => ["e", "f", nil, "d", "e", "f"]
  */
 
 static VALUE
 rb_ary_values_at(int argc, VALUE *argv, VALUE ary)
 {
-    return rb_get_values_at(ary, RARRAY_LEN(ary), argc, argv, rb_ary_entry);
+    long i, olen = RARRAY_LEN(ary);
+    VALUE result = rb_ary_new_capa(argc);
+    for (i = 0; i < argc; ++i) {
+        append_values_at_single(result, ary, olen, argv[i]);
+    }
+    RB_GC_GUARD(ary);
+    return result;
 }
 
 
 /*
  *  call-seq:
- *     ary.select { |item| block } -> new_ary
- *     ary.select                  -> Enumerator
+ *    array.select {|element| ... } -> new_array
+ *    array.select -> new_enumerator
  *
- *  Returns a new array containing all elements of +ary+
- *  for which the given +block+ returns a true value.
+ *  Calls the block, if given, with each element of +self+;
+ *  returns a new \Array containing those elements of +self+
+ *  for which the block returns a truthy value:
  *
- *  If no block is given, an Enumerator is returned instead.
+ *    a = [:foo, 'bar', 2, :bam]
+ *    a1 = a.select {|element| element.to_s.start_with?('b') }
+ *    a1 # => ["bar", :bam]
  *
- *     [1,2,3,4,5].select { |num|  num.even?  }   #=> [2, 4]
+ *  Returns a new \Enumerator if no block given:
  *
- *     a = %w{ a b c d e f }
- *     a.select { |v| v =~ /[aeiou]/ }  #=> ["a", "e"]
+ *    a = [:foo, 'bar', 2, :bam]
+ *    a.select # => #<Enumerator: [:foo, "bar", 2, :bam]:select>
  *
- *  See also Enumerable#select.
+ *  Array#filter is an alias for Array#select.
  */
 
 static VALUE
@@ -2799,65 +4010,110 @@ rb_ary_select(VALUE ary)
     RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
     result = rb_ary_new2(RARRAY_LEN(ary));
     for (i = 0; i < RARRAY_LEN(ary); i++) {
-	if (RTEST(rb_yield(RARRAY_AREF(ary, i)))) {
-	    rb_ary_push(result, rb_ary_elt(ary, i));
-	}
+        if (RTEST(rb_yield(RARRAY_AREF(ary, i)))) {
+            rb_ary_push(result, rb_ary_elt(ary, i));
+        }
     }
     return result;
 }
 
+struct select_bang_arg {
+    VALUE ary;
+    long len[2];
+};
+
+static VALUE
+select_bang_i(VALUE a)
+{
+    volatile struct select_bang_arg *arg = (void *)a;
+    VALUE ary = arg->ary;
+    long i1, i2;
+
+    for (i1 = i2 = 0; i1 < RARRAY_LEN(ary); arg->len[0] = ++i1) {
+        VALUE v = RARRAY_AREF(ary, i1);
+        if (!RTEST(rb_yield(v))) continue;
+        if (i1 != i2) {
+            rb_ary_store(ary, i2, v);
+        }
+        arg->len[1] = ++i2;
+    }
+    return (i1 == i2) ? Qnil : ary;
+}
+
+static VALUE
+select_bang_ensure(VALUE a)
+{
+    volatile struct select_bang_arg *arg = (void *)a;
+    VALUE ary = arg->ary;
+    long len = RARRAY_LEN(ary);
+    long i1 = arg->len[0], i2 = arg->len[1];
+
+    if (i2 < len && i2 < i1) {
+        long tail = 0;
+        rb_ary_modify(ary);
+        if (i1 < len) {
+            tail = len - i1;
+            RARRAY_PTR_USE_TRANSIENT(ary, ptr, {
+                    MEMMOVE(ptr + i2, ptr + i1, VALUE, tail);
+                });
+        }
+        ARY_SET_LEN(ary, i2 + tail);
+    }
+    return ary;
+}
+
 /*
  *  call-seq:
- *     ary.select!  {|item| block } -> ary or nil
- *     ary.select!                  -> Enumerator
+ *    array.select! {|element| ... } -> self or nil
+ *    array.select! -> new_enumerator
+ *
+ *  Calls the block, if given  with each element of +self+;
+ *  removes from +self+ those elements for which the block returns +false+ or +nil+.
  *
- *  Invokes the given block passing in successive elements from +self+,
- *  deleting elements for which the block returns a +false+ value.
+ *  Returns +self+ if any elements were removed:
  *
- *  If changes were made, it will return +self+, otherwise it returns +nil+.
+ *    a = [:foo, 'bar', 2, :bam]
+ *    a.select! {|element| element.to_s.start_with?('b') } # => ["bar", :bam]
  *
- *  See also Array#keep_if
+ *  Returns +nil+ if no elements were removed.
  *
- *  If no block is given, an Enumerator is returned instead.
+ *  Returns a new \Enumerator if no block given:
  *
+ *    a = [:foo, 'bar', 2, :bam]
+ *    a.select! # => #<Enumerator: [:foo, "bar", 2, :bam]:select!>
+ *
+ *  Array#filter! is an alias for Array#select!.
  */
 
 static VALUE
 rb_ary_select_bang(VALUE ary)
 {
-    long i1, i2;
+    struct select_bang_arg args;
 
     RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
     rb_ary_modify(ary);
-    for (i1 = i2 = 0; i1 < RARRAY_LEN(ary); i1++) {
-	VALUE v = RARRAY_AREF(ary, i1);
-	if (!RTEST(rb_yield(v))) continue;
-	if (i1 != i2) {
-	    rb_ary_store(ary, i2, v);
-	}
-	i2++;
-    }
 
-    if (i1 == i2) return Qnil;
-    if (i2 < i1)
-	ARY_SET_LEN(ary, i2);
-    return ary;
+    args.ary = ary;
+    args.len[0] = args.len[1] = 0;
+    return rb_ensure(select_bang_i, (VALUE)&args, select_bang_ensure, (VALUE)&args);
 }
 
 /*
  *  call-seq:
- *     ary.keep_if { |item| block } -> ary
- *     ary.keep_if                  -> Enumerator
+ *    array.keep_if {|element| ... } -> self
+ *    array.keep_if -> new_enumeration
  *
- *  Deletes every element of +self+ for which the given block evaluates to
- *  +false+.
+ *  Retains those elements for which the block returns a truthy value;
+ *  deletes all other elements; returns +self+:
  *
- *  See also Array#select!
+ *    a = [:foo, 'bar', 2, :bam]
+ *    a.keep_if {|element| element.to_s.start_with?('b') } # => ["bar", :bam]
  *
- *  If no block is given, an Enumerator is returned instead.
+ *  Returns a new \Enumerator if no block given:
+ *
+ *    a = [:foo, 'bar', 2, :bam]
+ *    a.keep_if # => #<Enumerator: [:foo, "bar", 2, :bam]:keep_if>
  *
- *     a = %w{ a b c d e f }
- *     a.keep_if { |v| v =~ /[aeiou]/ }  #=> ["a", "e"]
  */
 
 static VALUE
@@ -2873,32 +4129,48 @@ ary_resize_smaller(VALUE ary, long len)
 {
     rb_ary_modify(ary);
     if (RARRAY_LEN(ary) > len) {
-	ARY_SET_LEN(ary, len);
-	if (len * 2 < ARY_CAPA(ary) &&
-	    ARY_CAPA(ary) > ARY_DEFAULT_SIZE) {
-	    ary_resize_capa(ary, len * 2);
-	}
+        ARY_SET_LEN(ary, len);
+        if (len * 2 < ARY_CAPA(ary) &&
+            ARY_CAPA(ary) > ARY_DEFAULT_SIZE) {
+            ary_resize_capa(ary, len * 2);
+        }
     }
 }
 
 /*
  *  call-seq:
- *     ary.delete(obj)            -> item or nil
- *     ary.delete(obj) { block }  -> item or result of block
+ *    array.delete(obj) -> deleted_object
+ *    array.delete(obj) {|nosuch| ... } -> deleted_object or block_return
+ *
+ *  Removes zero or more elements from +self+.
+ *
+ *  When no block is given,
+ *  removes from +self+ each element +ele+ such that <tt>ele == obj</tt>;
+ *  returns the last deleted element:
+ *
+ *    s1 = 'bar'; s2 = 'bar'
+ *    a = [:foo, s1, 2, s2]
+ *    a.delete('bar') # => "bar"
+ *    a # => [:foo, 2]
+ *
+ *  Returns +nil+ if no elements removed.
+ *
+ *  When a block is given,
+ *  removes from +self+ each element +ele+ such that <tt>ele == obj</tt>.
+ *
+ *  If any such elements are found, ignores the block
+ *  and returns the last deleted element:
  *
- *  Deletes all items from +self+ that are equal to +obj+.
+ *    s1 = 'bar'; s2 = 'bar'
+ *    a = [:foo, s1, 2, s2]
+ *    deleted_obj = a.delete('bar') {|obj| fail 'Cannot happen' }
+ *    a # => [:foo, 2]
  *
- *  Returns the last deleted item, or +nil+ if no matching item is found.
+ *  If no such elements are found, returns the block's return value:
  *
- *  If the optional code block is given, the result of the block is returned if
- *  the item is not found.  (To remove +nil+ elements and get an informative
- *  return value, use Array#compact!)
+ *    a = [:foo, 'bar', 2]
+ *    a.delete(:nosuch) {|obj| "#{obj} not found" } # => "nosuch not found"
  *
- *     a = [ "a", "b", "b", "b", "c" ]
- *     a.delete("b")                   #=> "b"
- *     a                               #=> ["a", "c"]
- *     a.delete("z")                   #=> nil
- *     a.delete("z") { "not found" }   #=> "not found"
  */
 
 VALUE
@@ -2908,26 +4180,27 @@ rb_ary_delete(VALUE ary, VALUE item)
     long i1, i2;
 
     for (i1 = i2 = 0; i1 < RARRAY_LEN(ary); i1++) {
-	VALUE e = RARRAY_AREF(ary, i1);
+        VALUE e = RARRAY_AREF(ary, i1);
 
-	if (rb_equal(e, item)) {
-	    v = e;
-	    continue;
-	}
-	if (i1 != i2) {
-	    rb_ary_store(ary, i2, e);
-	}
-	i2++;
+        if (rb_equal(e, item)) {
+            v = e;
+            continue;
+        }
+        if (i1 != i2) {
+            rb_ary_store(ary, i2, e);
+        }
+        i2++;
     }
     if (RARRAY_LEN(ary) == i2) {
-	if (rb_block_given_p()) {
-	    return rb_yield(item);
-	}
-	return Qnil;
+        if (rb_block_given_p()) {
+            return rb_yield(item);
+        }
+        return Qnil;
     }
 
     ary_resize_smaller(ary, i2);
 
+    ary_verify(ary);
     return v;
 }
 
@@ -2937,18 +4210,18 @@ rb_ary_delete_same(VALUE ary, VALUE item)
     long i1, i2;
 
     for (i1 = i2 = 0; i1 < RARRAY_LEN(ary); i1++) {
-	VALUE e = RARRAY_AREF(ary, i1);
+        VALUE e = RARRAY_AREF(ary, i1);
 
-	if (e == item) {
-	    continue;
-	}
-	if (i1 != i2) {
-	    rb_ary_store(ary, i2, e);
-	}
-	i2++;
+        if (e == item) {
+            continue;
+        }
+        if (i1 != i2) {
+            rb_ary_store(ary, i2, e);
+        }
+        i2++;
     }
     if (RARRAY_LEN(ary) == i2) {
-	return;
+        return;
     }
 
     ary_resize_smaller(ary, i2);
@@ -2962,33 +4235,41 @@ rb_ary_delete_at(VALUE ary, long pos)
 
     if (pos >= len) return Qnil;
     if (pos < 0) {
-	pos += len;
-	if (pos < 0) return Qnil;
+        pos += len;
+        if (pos < 0) return Qnil;
     }
 
     rb_ary_modify(ary);
     del = RARRAY_AREF(ary, pos);
-    RARRAY_PTR_USE(ary, ptr, {
-	MEMMOVE(ptr+pos, ptr+pos+1, VALUE, len-pos-1);
+    RARRAY_PTR_USE_TRANSIENT(ary, ptr, {
+        MEMMOVE(ptr+pos, ptr+pos+1, VALUE, len-pos-1);
     });
     ARY_INCREASE_LEN(ary, -1);
-
+    ary_verify(ary);
     return del;
 }
 
 /*
  *  call-seq:
- *     ary.delete_at(index)  -> obj or nil
+ *    array.delete_at(index) -> deleted_object or nil
+ *
+ *  Deletes an element from +self+, per the given \Integer +index+.
+ *
+ *  When +index+ is non-negative, deletes the element at offset +index+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.delete_at(1) # => "bar"
+ *    a # => [:foo, 2]
  *
- *  Deletes the element at the specified +index+, returning that element, or
- *  +nil+ if the +index+ is out of range.
+ *  If index is too large, returns +nil+.
  *
- *  See also Array#slice!
+ *  When +index+ is negative, counts backward from the end of the array:
  *
- *     a = ["ant", "bat", "cat", "dog"]
- *     a.delete_at(2)    #=> "cat"
- *     a                 #=> ["ant", "bat", "dog"]
- *     a.delete_at(99)   #=> nil
+ *    a = [:foo, 'bar', 2]
+ *    a.delete_at(-2) # => "bar"
+ *    a # => [:foo, 2]
+ *
+ *  If +index+ is too small (far from zero), returns nil.
  */
 
 static VALUE
@@ -2997,73 +4278,133 @@ rb_ary_delete_at_m(VALUE ary, VALUE pos)
     return rb_ary_delete_at(ary, NUM2LONG(pos));
 }
 
+static VALUE
+ary_slice_bang_by_rb_ary_splice(VALUE ary, long pos, long len)
+{
+    const long orig_len = RARRAY_LEN(ary);
+
+    if (len < 0) {
+        return Qnil;
+    }
+    else if (pos < -orig_len) {
+        return Qnil;
+    }
+    else if (pos < 0) {
+        pos += orig_len;
+    }
+    else if (orig_len < pos) {
+        return Qnil;
+    }
+    if (orig_len < pos + len) {
+        len = orig_len - pos;
+    }
+    if (len == 0) {
+        return rb_ary_new2(0);
+    }
+    else {
+        VALUE arg2 = rb_ary_new4(len, RARRAY_CONST_PTR_TRANSIENT(ary)+pos);
+        rb_ary_splice(ary, pos, len, 0, 0);
+        return arg2;
+    }
+}
+
 /*
  *  call-seq:
- *     ary.slice!(index)         -> obj or nil
- *     ary.slice!(start, length) -> new_ary or nil
- *     ary.slice!(range)         -> new_ary or nil
- *
- *  Deletes the element(s) given by an +index+ (optionally up to +length+
- *  elements) or by a +range+.
- *
- *  Returns the deleted object (or objects), or +nil+ if the +index+ is out of
- *  range.
- *
- *     a = [ "a", "b", "c" ]
- *     a.slice!(1)     #=> "b"
- *     a               #=> ["a", "c"]
- *     a.slice!(-1)    #=> "c"
- *     a               #=> ["a"]
- *     a.slice!(100)   #=> nil
- *     a               #=> ["a"]
+ *    array.slice!(n) -> object or nil
+ *    array.slice!(start, length) -> new_array or nil
+ *    array.slice!(range) -> new_array or nil
+ *
+ *  Removes and returns elements from +self+.
+ *
+ *  When the only argument is an \Integer +n+,
+ *  removes and returns the _nth_ element in +self+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.slice!(1) # => "bar"
+ *    a # => [:foo, 2]
+ *
+ *  If +n+ is negative, counts backwards from the end of +self+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.slice!(-1) # => 2
+ *    a # => [:foo, "bar"]
+ *
+ *  If +n+ is out of range, returns +nil+.
+ *
+ *  When the only arguments are Integers +start+ and +length+,
+ *  removes +length+ elements from +self+ beginning at offset  +start+;
+ *  returns the deleted objects in a new \Array:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.slice!(0, 2) # => [:foo, "bar"]
+ *    a # => [2]
+ *
+ *  If <tt>start + length</tt> exceeds the array size,
+ *  removes and returns all elements from offset +start+ to the end:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.slice!(1, 50) # => ["bar", 2]
+ *    a # => [:foo]
+ *
+ *  If <tt>start == a.size</tt> and +length+ is non-negative,
+ *  returns a new empty \Array.
+ *
+ *  If +length+ is negative, returns +nil+.
+ *
+ *  When the only argument is a \Range object +range+,
+ *  treats <tt>range.min</tt> as +start+ above and <tt>range.size</tt> as +length+ above:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.slice!(1..2) # => ["bar", 2]
+ *    a # => [:foo]
+ *
+ *  If <tt>range.start == a.size</tt>, returns a new empty \Array.
+ *
+ *  If <tt>range.start</tt> is larger than the array size, returns +nil+.
+ *
+ *  If <tt>range.end</tt> is negative, counts backwards from the end of the array:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.slice!(0..-2) # => [:foo, "bar"]
+ *    a # => [2]
+ *
+ *  If <tt>range.start</tt> is negative,
+ *  calculates the start index backwards from the end of the array:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.slice!(-2..2) # => ["bar", 2]
+ *    a # => [:foo]
+ *
  */
 
 static VALUE
 rb_ary_slice_bang(int argc, VALUE *argv, VALUE ary)
 {
-    VALUE arg1, arg2;
-    long pos, len, orig_len;
+    VALUE arg1;
+    long pos, len;
 
     rb_ary_modify_check(ary);
+    rb_check_arity(argc, 1, 2);
+    arg1 = argv[0];
+
     if (argc == 2) {
-	pos = NUM2LONG(argv[0]);
-	len = NUM2LONG(argv[1]);
-      delete_pos_len:
-	if (len < 0) return Qnil;
-	orig_len = RARRAY_LEN(ary);
-	if (pos < 0) {
-	    pos += orig_len;
-	    if (pos < 0) return Qnil;
-	}
-	else if (orig_len < pos) return Qnil;
-	if (orig_len < pos + len) {
-	    len = orig_len - pos;
-	}
-	if (len == 0) return rb_ary_new2(0);
-	arg2 = rb_ary_new4(len, RARRAY_CONST_PTR(ary)+pos);
-	RBASIC_SET_CLASS(arg2, rb_obj_class(ary));
-	rb_ary_splice(ary, pos, len, Qundef);
-	return arg2;
-    }
-
-    if (argc != 1) {
-	/* error report */
-	rb_scan_args(argc, argv, "11", NULL, NULL);
+        pos = NUM2LONG(argv[0]);
+        len = NUM2LONG(argv[1]);
+        return ary_slice_bang_by_rb_ary_splice(ary, pos, len);
     }
-    arg1 = argv[0];
 
     if (!FIXNUM_P(arg1)) {
-	switch (rb_range_beg_len(arg1, &pos, &len, RARRAY_LEN(ary), 0)) {
-	  case Qtrue:
-	    /* valid range */
-	    goto delete_pos_len;
-	  case Qnil:
-	    /* invalid range */
-	    return Qnil;
-	  default:
-	    /* not a range */
-	    break;
-	}
+        switch (rb_range_beg_len(arg1, &pos, &len, RARRAY_LEN(ary), 0)) {
+          case Qtrue:
+            /* valid range */
+            return ary_slice_bang_by_rb_ary_splice(ary, pos, len);
+          case Qnil:
+            /* invalid range */
+            return Qnil;
+          default:
+            /* not a range */
+            break;
+        }
     }
 
     return rb_ary_delete_at(ary, NUM2LONG(arg1));
@@ -3075,68 +4416,89 @@ ary_reject(VALUE orig, VALUE result)
     long i;
 
     for (i = 0; i < RARRAY_LEN(orig); i++) {
-	VALUE v = RARRAY_AREF(orig, i);
-	if (!RTEST(rb_yield(v))) {
-	    rb_ary_push_1(result, v);
-	}
+        VALUE v = RARRAY_AREF(orig, i);
+
+        if (!RTEST(rb_yield(v))) {
+            rb_ary_push(result, v);
+        }
     }
     return result;
 }
 
 static VALUE
-ary_reject_bang(VALUE ary)
+reject_bang_i(VALUE a)
 {
-    long i;
-    VALUE result = Qnil;
+    volatile struct select_bang_arg *arg = (void *)a;
+    VALUE ary = arg->ary;
+    long i1, i2;
 
-    rb_ary_modify_check(ary);
-    for (i = 0; i < RARRAY_LEN(ary); ) {
-	VALUE v = RARRAY_AREF(ary, i);
-	if (RTEST(rb_yield(v))) {
-	    rb_ary_delete_at(ary, i);
-	    result = ary;
-	}
-	else {
-	    i++;
-	}
+    for (i1 = i2 = 0; i1 < RARRAY_LEN(ary); arg->len[0] = ++i1) {
+        VALUE v = RARRAY_AREF(ary, i1);
+        if (RTEST(rb_yield(v))) continue;
+        if (i1 != i2) {
+            rb_ary_store(ary, i2, v);
+        }
+        arg->len[1] = ++i2;
     }
-    return result;
+    return (i1 == i2) ? Qnil : ary;
+}
+
+static VALUE
+ary_reject_bang(VALUE ary)
+{
+    struct select_bang_arg args;
+    rb_ary_modify_check(ary);
+    args.ary = ary;
+    args.len[0] = args.len[1] = 0;
+    return rb_ensure(reject_bang_i, (VALUE)&args, select_bang_ensure, (VALUE)&args);
 }
 
 /*
  *  call-seq:
- *     ary.reject! { |item| block }  -> ary or nil
- *     ary.reject!                   -> Enumerator
+ *    array.reject! {|element| ... } -> self or nil
+ *    array.reject! -> new_enumerator
+ *
+ *  Removes each element for which the block returns a truthy value.
+ *
+ *  Returns +self+ if any elements removed:
+ *
+ *    a = [:foo, 'bar', 2, 'bat']
+ *    a.reject! {|element| element.to_s.start_with?('b') } # => [:foo, 2]
  *
- *  Equivalent to Array#delete_if, deleting elements from +self+ for which the
- *  block evaluates to +true+, but returns +nil+ if no changes were made.
+ *  Returns +nil+ if no elements removed.
  *
- *  The array is changed instantly every time the block is called, not after
- *  the iteration is over.
+ *  Returns a new \Enumerator if no block given:
  *
- *  See also Enumerable#reject and Array#delete_if.
+ *    a = [:foo, 'bar', 2]
+ *    a.reject! # => #<Enumerator: [:foo, "bar", 2]:reject!>
  *
- *  If no block is given, an Enumerator is returned instead.
  */
 
 static VALUE
 rb_ary_reject_bang(VALUE ary)
 {
     RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
+    rb_ary_modify(ary);
     return ary_reject_bang(ary);
 }
 
 /*
  *  call-seq:
- *     ary.reject  {|item| block }  -> new_ary
- *     ary.reject                   -> Enumerator
+ *    array.reject {|element| ... } -> new_array
+ *    array.reject -> new_enumerator
+ *
+ *  Returns a new \Array whose elements are all those from +self+
+ *  for which the block returns +false+ or +nil+:
  *
- *  Returns a new array containing the items in +self+ for which the given
- *  block is not +true+.
+ *    a = [:foo, 'bar', 2, 'bat']
+ *    a1 = a.reject {|element| element.to_s.start_with?('b') }
+ *    a1 # => [:foo, 2]
  *
- *  See also Array#delete_if
+ *  Returns a new \Enumerator if no block given:
+ *
+ *     a = [:foo, 'bar', 2]
+ *     a.reject # => #<Enumerator: [:foo, "bar", 2]:reject>
  *
- *  If no block is given, an Enumerator is returned instead.
  */
 
 static VALUE
@@ -3152,25 +4514,26 @@ rb_ary_reject(VALUE ary)
 
 /*
  *  call-seq:
- *     ary.delete_if { |item| block }  -> ary
- *     ary.delete_if                   -> Enumerator
+ *    array.delete_if {|element| ... } -> self
+ *    array.delete_if -> Enumerator
  *
- *  Deletes every element of +self+ for which block evaluates to +true+.
+ *  Removes each element in +self+ for which the block returns a truthy value;
+ *  returns +self+:
  *
- *  The array is changed instantly every time the block is called, not after
- *  the iteration is over.
+ *    a = [:foo, 'bar', 2, 'bat']
+ *    a.delete_if {|element| element.to_s.start_with?('b') } # => [:foo, 2]
  *
- *  See also Array#reject!
+ *  Returns a new \Enumerator if no block given:
  *
- *  If no block is given, an Enumerator is returned instead.
+ *    a = [:foo, 'bar', 2]
+ *    a.delete_if # => #<Enumerator: [:foo, "bar", 2]:delete_if>
  *
- *     scores = [ 97, 42, 75 ]
- *     scores.delete_if {|score| score < 80 }   #=> [97]
- */
+3 */
 
 static VALUE
 rb_ary_delete_if(VALUE ary)
 {
+    ary_verify(ary);
     RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
     ary_reject_bang(ary);
     return ary;
@@ -3180,9 +4543,9 @@ static VALUE
 take_i(RB_BLOCK_CALL_FUNC_ARGLIST(val, cbarg))
 {
     VALUE *args = (VALUE *)cbarg;
-    if (args[1]-- == 0) rb_iter_break();
     if (argc > 1) val = rb_ary_new4(argc, argv);
     rb_ary_push(args[0], val);
+    if (--args[1] == 0) rb_iter_break();
     return Qnil;
 }
 
@@ -3192,38 +4555,71 @@ take_items(VALUE obj, long n)
     VALUE result = rb_check_array_type(obj);
     VALUE args[2];
 
+    if (n == 0) return result;
     if (!NIL_P(result)) return rb_ary_subseq(result, 0, n);
     result = rb_ary_new2(n);
     args[0] = result; args[1] = (VALUE)n;
-    if (rb_check_block_call(obj, idEach, 0, 0, take_i, (VALUE)args) == Qundef)
-	rb_raise(rb_eTypeError, "wrong argument type %"PRIsVALUE" (must respond to :each)",
-		 rb_obj_class(obj));
+    if (UNDEF_P(rb_check_block_call(obj, idEach, 0, 0, take_i, (VALUE)args)))
+        rb_raise(rb_eTypeError, "wrong argument type %"PRIsVALUE" (must respond to :each)",
+                 rb_obj_class(obj));
     return result;
 }
 
 
 /*
  *  call-seq:
- *     ary.zip(arg, ...)                  -> new_ary
- *     ary.zip(arg, ...) { |arr| block }  -> nil
+ *    array.zip(*other_arrays) -> new_array
+ *    array.zip(*other_arrays) {|other_array| ... } -> nil
+ *
+ *  When no block given, returns a new \Array +new_array+ of size <tt>self.size</tt>
+ *  whose elements are Arrays.
+ *
+ *  Each nested array <tt>new_array[n]</tt> is of size <tt>other_arrays.size+1</tt>,
+ *  and contains:
+ *
+ *  - The _nth_ element of +self+.
+ *  - The _nth_ element of each of the +other_arrays+.
+ *
+ *  If all +other_arrays+ and +self+ are the same size:
+ *
+ *    a = [:a0, :a1, :a2, :a3]
+ *    b = [:b0, :b1, :b2, :b3]
+ *    c = [:c0, :c1, :c2, :c3]
+ *    d = a.zip(b, c)
+ *    d # => [[:a0, :b0, :c0], [:a1, :b1, :c1], [:a2, :b2, :c2], [:a3, :b3, :c3]]
+ *
+ *  If any array in +other_arrays+ is smaller than +self+,
+ *  fills to <tt>self.size</tt> with +nil+:
+ *
+ *    a = [:a0, :a1, :a2, :a3]
+ *    b = [:b0, :b1, :b2]
+ *    c = [:c0, :c1]
+ *    d = a.zip(b, c)
+ *    d # => [[:a0, :b0, :c0], [:a1, :b1, :c1], [:a2, :b2, nil], [:a3, nil, nil]]
+ *
+ *  If any array in +other_arrays+ is larger than +self+,
+ *  its trailing elements are ignored:
  *
- *  Converts any arguments to arrays, then merges elements of +self+ with
- *  corresponding elements from each argument.
+ *    a = [:a0, :a1, :a2, :a3]
+ *    b = [:b0, :b1, :b2, :b3, :b4]
+ *    c = [:c0, :c1, :c2, :c3, :c4, :c5]
+ *    d = a.zip(b, c)
+ *    d # => [[:a0, :b0, :c0], [:a1, :b1, :c1], [:a2, :b2, :c2], [:a3, :b3, :c3]]
  *
- *  This generates a sequence of <code>ary.size</code> _n_-element arrays,
- *  where _n_ is one more than the count of arguments.
+ *  When a block is given, calls the block with each of the sub-arrays (formed as above); returns +nil+:
  *
- *  If the size of any argument is less than the size of the initial array,
- *  +nil+ values are supplied.
+ *    a = [:a0, :a1, :a2, :a3]
+ *    b = [:b0, :b1, :b2, :b3]
+ *    c = [:c0, :c1, :c2, :c3]
+ *    a.zip(b, c) {|sub_array| p sub_array} # => nil
  *
- *  If a block is given, it is invoked for each output +array+, otherwise an
- *  array of arrays is returned.
+ *  Output:
+ *
+ *    [:a0, :b0, :c0]
+ *    [:a1, :b1, :c1]
+ *    [:a2, :b2, :c2]
+ *    [:a3, :b3, :c3]
  *
- *     a = [ 4, 5, 6 ]
- *     b = [ 7, 8, 9 ]
- *     [1, 2, 3].zip(a, b)   #=> [[1, 4, 7], [2, 5, 8], [3, 6, 9]]
- *     [1, 2].zip(a, b)      #=> [[1, 4, 7], [2, 5, 8]]
- *     a.zip([1, 2], [8])    #=> [[4, 1, 8], [5, 2, nil], [6, nil, nil]]
  */
 
 static VALUE
@@ -3234,51 +4630,51 @@ rb_ary_zip(int argc, VALUE *argv, VALUE ary)
     VALUE result = Qnil;
 
     for (i=0; i<argc; i++) {
-	argv[i] = take_items(argv[i], len);
+        argv[i] = take_items(argv[i], len);
     }
 
     if (rb_block_given_p()) {
-	int arity = rb_block_arity();
-
-	if (arity > 1) {
-	    VALUE work, *tmp;
-
-	    tmp = ALLOCV_N(VALUE, work, argc+1);
-
-	    for (i=0; i<RARRAY_LEN(ary); i++) {
-		tmp[0] = RARRAY_AREF(ary, i);
-		for (j=0; j<argc; j++) {
-		    tmp[j+1] = rb_ary_elt(argv[j], i);
-		}
-		rb_yield_values2(argc+1, tmp);
-	    }
-
-	    if (work) ALLOCV_END(work);
-	}
-	else {
-	    for (i=0; i<RARRAY_LEN(ary); i++) {
-		VALUE tmp = rb_ary_new2(argc+1);
-
-		rb_ary_push(tmp, RARRAY_AREF(ary, i));
-		for (j=0; j<argc; j++) {
-		    rb_ary_push(tmp, rb_ary_elt(argv[j], i));
-		}
-		rb_yield(tmp);
-	    }
-	}
+        int arity = rb_block_arity();
+
+        if (arity > 1) {
+            VALUE work, *tmp;
+
+            tmp = ALLOCV_N(VALUE, work, argc+1);
+
+            for (i=0; i<RARRAY_LEN(ary); i++) {
+                tmp[0] = RARRAY_AREF(ary, i);
+                for (j=0; j<argc; j++) {
+                    tmp[j+1] = rb_ary_elt(argv[j], i);
+                }
+                rb_yield_values2(argc+1, tmp);
+            }
+
+            if (work) ALLOCV_END(work);
+        }
+        else {
+            for (i=0; i<RARRAY_LEN(ary); i++) {
+                VALUE tmp = rb_ary_new2(argc+1);
+
+                rb_ary_push(tmp, RARRAY_AREF(ary, i));
+                for (j=0; j<argc; j++) {
+                    rb_ary_push(tmp, rb_ary_elt(argv[j], i));
+                }
+                rb_yield(tmp);
+            }
+        }
     }
     else {
-	result = rb_ary_new_capa(len);
+        result = rb_ary_new_capa(len);
 
-	for (i=0; i<len; i++) {
-	    VALUE tmp = rb_ary_new_capa(argc+1);
+        for (i=0; i<len; i++) {
+            VALUE tmp = rb_ary_new_capa(argc+1);
 
-	    rb_ary_push(tmp, RARRAY_AREF(ary, i));
-	    for (j=0; j<argc; j++) {
-		rb_ary_push(tmp, rb_ary_elt(argv[j], i));
-	    }
-	    rb_ary_push(result, tmp);
-	}
+            rb_ary_push(tmp, RARRAY_AREF(ary, i));
+            for (j=0; j<argc; j++) {
+                rb_ary_push(tmp, rb_ary_elt(argv[j], i));
+            }
+            rb_ary_push(result, tmp);
+        }
     }
 
     return result;
@@ -3286,15 +4682,14 @@ rb_ary_zip(int argc, VALUE *argv, VALUE ary)
 
 /*
  *  call-seq:
- *     ary.transpose -> new_ary
+ *    array.transpose -> new_array
  *
- *  Assumes that +self+ is an array of arrays and transposes the rows and
- *  columns.
+ *  Transposes the rows and columns in an \Array of Arrays;
+ *  the nested Arrays must all be the same size:
  *
- *     a = [[1,2], [3,4], [5,6]]
- *     a.transpose   #=> [[1, 3, 5], [2, 4, 6]]
+ *    a = [[:a0, :a1], [:b0, :b1], [:c0, :c1]]
+ *    a.transpose # => [[:a0, :b0, :c0], [:a1, :b1, :c1]]
  *
- *  If the length of the subarrays don't match, an IndexError is raised.
  */
 
 static VALUE
@@ -3306,36 +4701,34 @@ rb_ary_transpose(VALUE ary)
     alen = RARRAY_LEN(ary);
     if (alen == 0) return rb_ary_dup(ary);
     for (i=0; i<alen; i++) {
-	tmp = to_ary(rb_ary_elt(ary, i));
-	if (elen < 0) {		/* first element */
-	    elen = RARRAY_LEN(tmp);
-	    result = rb_ary_new2(elen);
-	    for (j=0; j<elen; j++) {
-		rb_ary_store(result, j, rb_ary_new2(alen));
-	    }
-	}
-	else if (elen != RARRAY_LEN(tmp)) {
-	    rb_raise(rb_eIndexError, "element size differs (%ld should be %ld)",
-		     RARRAY_LEN(tmp), elen);
-	}
-	for (j=0; j<elen; j++) {
-	    rb_ary_store(rb_ary_elt(result, j), i, rb_ary_elt(tmp, j));
-	}
+        tmp = to_ary(rb_ary_elt(ary, i));
+        if (elen < 0) {		/* first element */
+            elen = RARRAY_LEN(tmp);
+            result = rb_ary_new2(elen);
+            for (j=0; j<elen; j++) {
+                rb_ary_store(result, j, rb_ary_new2(alen));
+            }
+        }
+        else if (elen != RARRAY_LEN(tmp)) {
+            rb_raise(rb_eIndexError, "element size differs (%ld should be %ld)",
+                     RARRAY_LEN(tmp), elen);
+        }
+        for (j=0; j<elen; j++) {
+            rb_ary_store(rb_ary_elt(result, j), i, rb_ary_elt(tmp, j));
+        }
     }
     return result;
 }
 
 /*
  *  call-seq:
- *     ary.replace(other_ary)  -> ary
- *     ary.initialize_copy(other_ary)	-> ary
+ *    array.replace(other_array) -> self
  *
- *  Replaces the contents of +self+ with the contents of +other_ary+,
- *  truncating or expanding if necessary.
+ *  Replaces the content of +self+ with the content of +other_array+; returns +self+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.replace(['foo', :bar, 3]) # => ["foo", :bar, 3]
  *
- *     a = [ "a", "b", "c", "d", "e" ]
- *     a.replace([ "x", "y", "z" ])   #=> ["x", "y", "z"]
- *     a                              #=> ["x", "y", "z"]
  */
 
 VALUE
@@ -3345,176 +4738,347 @@ rb_ary_replace(VALUE copy, VALUE orig)
     orig = to_ary(orig);
     if (copy == orig) return copy;
 
-    if (RARRAY_LEN(orig) <= RARRAY_EMBED_LEN_MAX) {
-        VALUE shared = 0;
+    rb_ary_reset(copy);
 
-        if (ARY_OWNS_HEAP_P(copy)) {
-	    RARRAY_PTR_USE(copy, ptr, ruby_sized_xfree(ptr, ARY_HEAP_SIZE(copy)));
-	}
-        else if (ARY_SHARED_P(copy)) {
-            shared = ARY_SHARED(copy);
-            FL_UNSET_SHARED(copy);
-        }
-        FL_SET_EMBED(copy);
-	ary_memcpy(copy, 0, RARRAY_LEN(orig), RARRAY_CONST_PTR(orig));
-        if (shared) {
-            rb_ary_decrement_share(shared);
-        }
-        ARY_SET_LEN(copy, RARRAY_LEN(orig));
+    /* orig has enough space to embed the contents of orig. */
+    if (RARRAY_LEN(orig) <= ary_embed_capa(copy)) {
+        assert(ARY_EMBED_P(copy));
+        ary_memcpy(copy, 0, RARRAY_LEN(orig), RARRAY_CONST_PTR_TRANSIENT(orig));
+        ARY_SET_EMBED_LEN(copy, RARRAY_LEN(orig));
     }
+#if USE_RVARGC
+    /* orig is embedded but copy does not have enough space to embed the
+     * contents of orig. */
+    else if (ARY_EMBED_P(orig)) {
+        long len = ARY_EMBED_LEN(orig);
+        VALUE *ptr = ary_heap_alloc(copy, len);
+
+        FL_UNSET_EMBED(copy);
+        ARY_SET_PTR(copy, ptr);
+        ARY_SET_LEN(copy, len);
+        ARY_SET_CAPA(copy, len);
+
+        // No allocation and exception expected that could leave `copy` in a
+        // bad state from the edits above.
+        ary_memcpy(copy, 0, len, RARRAY_CONST_PTR_TRANSIENT(orig));
+    }
+#endif
+    /* Otherwise, orig is on heap and copy does not have enough space to embed
+     * the contents of orig. */
     else {
-        VALUE shared = ary_make_shared(orig);
-        if (ARY_OWNS_HEAP_P(copy)) {
-	    RARRAY_PTR_USE(copy, ptr, ruby_sized_xfree(ptr, ARY_HEAP_SIZE(copy)));
-        }
-        else {
-            rb_ary_unshare_safe(copy);
-        }
+        VALUE shared_root = ary_make_shared(orig);
         FL_UNSET_EMBED(copy);
-        ARY_SET_PTR(copy, RARRAY_CONST_PTR(orig));
-        ARY_SET_LEN(copy, RARRAY_LEN(orig));
-        rb_ary_set_shared(copy, shared);
+        ARY_SET_PTR(copy, ARY_HEAP_PTR(orig));
+        ARY_SET_LEN(copy, ARY_HEAP_LEN(orig));
+        rb_ary_set_shared(copy, shared_root);
     }
+    ary_verify(copy);
     return copy;
 }
 
 /*
  *  call-seq:
- *     ary.clear    -> ary
+ *     array.clear -> self
  *
- *  Removes all elements from +self+.
+ *  Removes all elements from +self+:
+ *
+ *    a = [:foo, 'bar', 2]
+ *    a.clear # => []
  *
- *     a = [ "a", "b", "c", "d", "e" ]
- *     a.clear    #=> [ ]
  */
 
 VALUE
 rb_ary_clear(VALUE ary)
 {
     rb_ary_modify_check(ary);
-    ARY_SET_LEN(ary, 0);
     if (ARY_SHARED_P(ary)) {
-	if (!ARY_EMBED_P(ary)) {
-	    rb_ary_unshare(ary);
-	    FL_SET_EMBED(ary);
-	}
+        if (!ARY_EMBED_P(ary)) {
+            rb_ary_unshare(ary);
+            FL_SET_EMBED(ary);
+            ARY_SET_EMBED_LEN(ary, 0);
+        }
     }
-    else if (ARY_DEFAULT_SIZE * 2 < ARY_CAPA(ary)) {
-	ary_resize_capa(ary, ARY_DEFAULT_SIZE * 2);
+    else {
+        ARY_SET_LEN(ary, 0);
+        if (ARY_DEFAULT_SIZE * 2 < ARY_CAPA(ary)) {
+            ary_resize_capa(ary, ARY_DEFAULT_SIZE * 2);
+        }
     }
+    ary_verify(ary);
     return ary;
 }
 
 /*
  *  call-seq:
- *     ary.fill(obj)                                 -> ary
- *     ary.fill(obj, start [, length])               -> ary
- *     ary.fill(obj, range )                         -> ary
- *     ary.fill { |index| block }                    -> ary
- *     ary.fill(start [, length] ) { |index| block } -> ary
- *     ary.fill(range) { |index| block }             -> ary
+ *    array.fill(obj) -> self
+ *    array.fill(obj, start) -> self
+ *    array.fill(obj, start, length) -> self
+ *    array.fill(obj, range) -> self
+ *    array.fill {|index| ... } -> self
+ *    array.fill(start) {|index| ... } -> self
+ *    array.fill(start, length) {|index| ... } -> self
+ *    array.fill(range) {|index| ... } -> self
+ *
+ *  Replaces specified elements in +self+ with specified objects; returns +self+.
+ *
+ *  With argument +obj+ and no block given, replaces all elements with that one object:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a # => ["a", "b", "c", "d"]
+ *    a.fill(:X) # => [:X, :X, :X, :X]
+ *
+ *  With arguments +obj+ and \Integer +start+, and no block given,
+ *  replaces elements based on the given start.
+ *
+ *  If +start+ is in range (<tt>0 <= start < array.size</tt>),
+ *  replaces all elements from offset +start+ through the end:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(:X, 2) # => ["a", "b", :X, :X]
+ *
+ *  If +start+ is too large (<tt>start >= array.size</tt>), does nothing:
  *
- *  The first three forms set the selected elements of +self+ (which
- *  may be the entire array) to +obj+.
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(:X, 4) # => ["a", "b", "c", "d"]
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(:X, 5) # => ["a", "b", "c", "d"]
  *
- *  A +start+ of +nil+ is equivalent to zero.
+ *  If +start+ is negative, counts from the end (starting index is <tt>start + array.size</tt>):
  *
- *  A +length+ of +nil+ is equivalent to the length of the array.
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(:X, -2) # => ["a", "b", :X, :X]
  *
- *  The last three forms fill the array with the value of the given block,
- *  which is passed the absolute index of each element to be filled.
+ *  If +start+ is too small (less than and far from zero), replaces all elements:
  *
- *  Negative values of +start+ count from the end of the array, where +-1+ is
- *  the last element.
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(:X, -6) # => [:X, :X, :X, :X]
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(:X, -50) # => [:X, :X, :X, :X]
+ *
+ *  With arguments +obj+, \Integer +start+, and \Integer +length+, and no block given,
+ *  replaces elements based on the given +start+ and +length+.
+ *
+ *  If +start+ is in range, replaces +length+ elements beginning at offset +start+:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(:X, 1, 1) # => ["a", :X, "c", "d"]
+ *
+ *  If +start+ is negative, counts from the end:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(:X, -2, 1) # => ["a", "b", :X, "d"]
+ *
+ *  If +start+ is large (<tt>start >= array.size</tt>), extends +self+ with +nil+:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(:X, 5, 0) # => ["a", "b", "c", "d", nil]
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(:X, 5, 2) # => ["a", "b", "c", "d", nil, :X, :X]
+ *
+ *  If +length+ is zero or negative, replaces no elements:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(:X, 1, 0) # => ["a", "b", "c", "d"]
+ *    a.fill(:X, 1, -1) # => ["a", "b", "c", "d"]
+ *
+ *  With arguments +obj+ and \Range +range+, and no block given,
+ *  replaces elements based on the given range.
+ *
+ *  If the range is positive and ascending (<tt>0 < range.begin <= range.end</tt>),
+ *  replaces elements from <tt>range.begin</tt> to <tt>range.end</tt>:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(:X, (1..1)) # => ["a", :X, "c", "d"]
+ *
+ *  If <tt>range.first</tt> is negative, replaces no elements:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(:X, (-1..1)) # => ["a", "b", "c", "d"]
+ *
+ *  If <tt>range.last</tt> is negative, counts from the end:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(:X, (0..-2)) # => [:X, :X, :X, "d"]
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(:X, (1..-2)) # => ["a", :X, :X, "d"]
+ *
+ *  If <tt>range.last</tt> and <tt>range.last</tt> are both negative,
+ *  both count from the end of the array:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(:X, (-1..-1)) # => ["a", "b", "c", :X]
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(:X, (-2..-2)) # => ["a", "b", :X, "d"]
+ *
+ *  With no arguments and a block given, calls the block with each index;
+ *  replaces the corresponding element with the block's return value:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill { |index| "new_#{index}" } # => ["new_0", "new_1", "new_2", "new_3"]
+ *
+ *  With argument +start+ and a block given, calls the block with each index
+ *  from offset +start+ to the end; replaces the corresponding element
+ *  with the block's return value.
+ *
+ *  If start is in range (<tt>0 <= start < array.size</tt>),
+ *  replaces from offset +start+ to the end:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(1) { |index| "new_#{index}" } # => ["a", "new_1", "new_2", "new_3"]
+ *
+ *  If +start+ is too large(<tt>start >= array.size</tt>), does nothing:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(4) { |index| fail 'Cannot happen' } # => ["a", "b", "c", "d"]
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(4) { |index| fail 'Cannot happen' } # => ["a", "b", "c", "d"]
+ *
+ *  If +start+ is negative, counts from the end:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(-2) { |index| "new_#{index}" } # => ["a", "b", "new_2", "new_3"]
+ *
+ *  If start is too small (<tt>start <= -array.size</tt>, replaces all elements:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(-6) { |index| "new_#{index}" } # => ["new_0", "new_1", "new_2", "new_3"]
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(-50) { |index| "new_#{index}" } # => ["new_0", "new_1", "new_2", "new_3"]
+ *
+ *  With arguments +start+ and +length+, and a block given,
+ *  calls the block for each index specified by start length;
+ *  replaces the corresponding element with the block's return value.
+ *
+ *  If +start+ is in range, replaces +length+ elements beginning at offset +start+:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(1, 1) { |index| "new_#{index}" } # => ["a", "new_1", "c", "d"]
+ *
+ *  If start is negative, counts from the end:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(-2, 1) { |index| "new_#{index}" } # => ["a", "b", "new_2", "d"]
+ *
+ *  If +start+ is large (<tt>start >= array.size</tt>), extends +self+ with +nil+:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(5, 0) { |index| "new_#{index}" } # => ["a", "b", "c", "d", nil]
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(5, 2) { |index| "new_#{index}" } # => ["a", "b", "c", "d", nil, "new_5", "new_6"]
+ *
+ *  If +length+ is zero or less, replaces no elements:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(1, 0) { |index| "new_#{index}" } # => ["a", "b", "c", "d"]
+ *    a.fill(1, -1) { |index| "new_#{index}" } # => ["a", "b", "c", "d"]
+ *
+ *  With arguments +obj+ and +range+, and a block given,
+ *  calls the block with each index in the given range;
+ *  replaces the corresponding element with the block's return value.
+ *
+ *  If the range is positive and ascending (<tt>range 0 < range.begin <= range.end</tt>,
+ *  replaces elements from <tt>range.begin</tt> to <tt>range.end</tt>:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(1..1) { |index| "new_#{index}" } # => ["a", "new_1", "c", "d"]
+ *
+ *  If +range.first+ is negative, does nothing:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(-1..1) { |index| fail 'Cannot happen' } # => ["a", "b", "c", "d"]
+ *
+ *  If <tt>range.last</tt> is negative, counts from the end:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(0..-2) { |index| "new_#{index}" } # => ["new_0", "new_1", "new_2", "d"]
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(1..-2) { |index| "new_#{index}" } # => ["a", "new_1", "new_2", "d"]
+ *
+ *  If <tt>range.first</tt> and <tt>range.last</tt> are both negative,
+ *  both count from the end:
+ *
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(-1..-1) { |index| "new_#{index}" } # => ["a", "b", "c", "new_3"]
+ *    a = ['a', 'b', 'c', 'd']
+ *    a.fill(-2..-2) { |index| "new_#{index}" } # => ["a", "b", "new_2", "d"]
  *
- *     a = [ "a", "b", "c", "d" ]
- *     a.fill("x")              #=> ["x", "x", "x", "x"]
- *     a.fill("z", 2, 2)        #=> ["x", "x", "z", "z"]
- *     a.fill("y", 0..1)        #=> ["y", "y", "z", "z"]
- *     a.fill { |i| i*i }       #=> [0, 1, 4, 9]
- *     a.fill(-2) { |i| i*i*i } #=> [0, 1, 8, 27]
  */
 
 static VALUE
 rb_ary_fill(int argc, VALUE *argv, VALUE ary)
 {
-    VALUE item, arg1, arg2;
+    VALUE item = Qundef, arg1, arg2;
     long beg = 0, end = 0, len = 0;
-    int block_p = FALSE;
 
     if (rb_block_given_p()) {
-	block_p = TRUE;
-	rb_scan_args(argc, argv, "02", &arg1, &arg2);
-	argc += 1;		/* hackish */
+        rb_scan_args(argc, argv, "02", &arg1, &arg2);
+        argc += 1;		/* hackish */
     }
     else {
-	rb_scan_args(argc, argv, "12", &item, &arg1, &arg2);
+        rb_scan_args(argc, argv, "12", &item, &arg1, &arg2);
     }
     switch (argc) {
       case 1:
-	beg = 0;
-	len = RARRAY_LEN(ary);
-	break;
+        beg = 0;
+        len = RARRAY_LEN(ary);
+        break;
       case 2:
-	if (rb_range_beg_len(arg1, &beg, &len, RARRAY_LEN(ary), 1)) {
-	    break;
-	}
-	/* fall through */
+        if (rb_range_beg_len(arg1, &beg, &len, RARRAY_LEN(ary), 1)) {
+            break;
+        }
+        /* fall through */
       case 3:
-	beg = NIL_P(arg1) ? 0 : NUM2LONG(arg1);
-	if (beg < 0) {
-	    beg = RARRAY_LEN(ary) + beg;
-	    if (beg < 0) beg = 0;
-	}
-	len = NIL_P(arg2) ? RARRAY_LEN(ary) - beg : NUM2LONG(arg2);
-	break;
+        beg = NIL_P(arg1) ? 0 : NUM2LONG(arg1);
+        if (beg < 0) {
+            beg = RARRAY_LEN(ary) + beg;
+            if (beg < 0) beg = 0;
+        }
+        len = NIL_P(arg2) ? RARRAY_LEN(ary) - beg : NUM2LONG(arg2);
+        break;
     }
     rb_ary_modify(ary);
     if (len < 0) {
         return ary;
     }
     if (beg >= ARY_MAX_SIZE || len > ARY_MAX_SIZE - beg) {
-	rb_raise(rb_eArgError, "argument too big");
+        rb_raise(rb_eArgError, "argument too big");
     }
     end = beg + len;
     if (RARRAY_LEN(ary) < end) {
-	if (end >= ARY_CAPA(ary)) {
-	    ary_resize_capa(ary, end);
-	}
-	ary_mem_clear(ary, RARRAY_LEN(ary), end - RARRAY_LEN(ary));
-	ARY_SET_LEN(ary, end);
+        if (end >= ARY_CAPA(ary)) {
+            ary_resize_capa(ary, end);
+        }
+        ary_mem_clear(ary, RARRAY_LEN(ary), end - RARRAY_LEN(ary));
+        ARY_SET_LEN(ary, end);
     }
 
-    if (block_p) {
-	VALUE v;
-	long i;
+    if (UNDEF_P(item)) {
+        VALUE v;
+        long i;
 
-	for (i=beg; i<end; i++) {
-	    v = rb_yield(LONG2NUM(i));
-	    if (i>=RARRAY_LEN(ary)) break;
-	    RARRAY_ASET(ary, i, v);
-	}
+        for (i=beg; i<end; i++) {
+            v = rb_yield(LONG2NUM(i));
+            if (i>=RARRAY_LEN(ary)) break;
+            ARY_SET(ary, i, v);
+        }
     }
     else {
-	ary_memfill(ary, beg, len, item);
+        ary_memfill(ary, beg, len, item);
     }
     return ary;
 }
 
 /*
  *  call-seq:
- *     ary + other_ary   -> new_ary
+ *    array + other_array -> new_array
  *
- *  Concatenation --- Returns a new array built by concatenating the
- *  two arrays together to produce a third array.
+ *  Returns a new \Array containing all elements of +array+
+ *  followed by all elements of +other_array+:
  *
- *     [ 1, 2, 3 ] + [ 4, 5 ]    #=> [ 1, 2, 3, 4, 5 ]
- *     a = [ "a", "b", "c" ]
- *     c = a + [ "d", "e", "f" ]
- *     c                         #=> [ "a", "b", "c", "d", "e", "f" ]
- *     a                         #=> [ "a", "b", "c" ]
+ *    a = [0, 1] + [2, 3]
+ *    a # => [0, 1, 2, 3]
  *
- *  See also Array#concat.
+ *  Related: #concat.
  */
 
 VALUE
@@ -3529,52 +5093,75 @@ rb_ary_plus(VALUE x, VALUE y)
     len = xlen + ylen;
     z = rb_ary_new2(len);
 
-    ary_memcpy(z, 0, xlen, RARRAY_CONST_PTR(x));
-    ary_memcpy(z, xlen, ylen, RARRAY_CONST_PTR(y));
+    ary_memcpy(z, 0, xlen, RARRAY_CONST_PTR_TRANSIENT(x));
+    ary_memcpy(z, xlen, ylen, RARRAY_CONST_PTR_TRANSIENT(y));
     ARY_SET_LEN(z, len);
     return z;
 }
 
+static VALUE
+ary_append(VALUE x, VALUE y)
+{
+    long n = RARRAY_LEN(y);
+    if (n > 0) {
+        rb_ary_splice(x, RARRAY_LEN(x), 0, RARRAY_CONST_PTR_TRANSIENT(y), n);
+    }
+    RB_GC_GUARD(y);
+    return x;
+}
+
 /*
  *  call-seq:
- *     ary.concat(other_ary)   -> ary
+ *    array.concat(*other_arrays) -> self
  *
- *  Appends the elements of +other_ary+ to +self+.
+ *  Adds to +array+ all elements from each \Array in +other_arrays+; returns +self+:
  *
- *     [ "a", "b" ].concat( ["c", "d"] ) #=> [ "a", "b", "c", "d" ]
- *     a = [ 1, 2, 3 ]
- *     a.concat( [ 4, 5 ] )
- *     a                                 #=> [ 1, 2, 3, 4, 5 ]
- *
- *  See also Array#+.
+ *    a = [0, 1]
+ *    a.concat([2, 3], [4, 5]) # => [0, 1, 2, 3, 4, 5]
  */
 
-VALUE
-rb_ary_concat(VALUE x, VALUE y)
+static VALUE
+rb_ary_concat_multi(int argc, VALUE *argv, VALUE ary)
 {
-    rb_ary_modify_check(x);
-    y = to_ary(y);
-    if (RARRAY_LEN(y) > 0) {
-	rb_ary_splice(x, RARRAY_LEN(x), 0, y);
+    rb_ary_modify_check(ary);
+
+    if (argc == 1) {
+        rb_ary_concat(ary, argv[0]);
     }
-    return x;
+    else if (argc > 1) {
+        int i;
+        VALUE args = rb_ary_hidden_new(argc);
+        for (i = 0; i < argc; i++) {
+            rb_ary_concat(args, argv[i]);
+        }
+        ary_append(ary, args);
+    }
+
+    ary_verify(ary);
+    return ary;
 }
 
+VALUE
+rb_ary_concat(VALUE x, VALUE y)
+{
+    return ary_append(x, to_ary(y));
+}
 
 /*
  *  call-seq:
- *     ary * int     -> new_ary
- *     ary * str     -> new_string
+ *    array * n -> new_array
+ *    array * string_separator -> new_string
  *
- *  Repetition --- With a String argument, equivalent to
- *  <code>ary.join(str)</code>.
+ *  When non-negative argument \Integer +n+ is given,
+ *  returns a new \Array built by concatenating the +n+ copies of +self+:
  *
- *  Otherwise, returns a new array built by concatenating the +int+ copies of
- *  +self+.
+ *    a = ['x', 'y']
+ *    a * 3 # => ["x", "y", "x", "y", "x", "y"]
  *
+ *  When \String argument +string_separator+ is given,
+ *  equivalent to <tt>array.join(string_separator)</tt>:
  *
- *     [ 1, 2, 3 ] * 3    #=> [ 1, 2, 3, 1, 2, 3, 1, 2, 3 ]
- *     [ 1, 2, 3 ] * ","  #=> "1,2,3"
+ *    [0, [0, 1], {foo: 0}] * ', ' # => "0, 0, 1, {:foo=>0}"
  *
  */
 
@@ -3587,61 +5174,54 @@ rb_ary_times(VALUE ary, VALUE times)
 
     tmp = rb_check_string_type(times);
     if (!NIL_P(tmp)) {
-	return rb_ary_join(ary, tmp);
+        return rb_ary_join(ary, tmp);
     }
 
     len = NUM2LONG(times);
     if (len == 0) {
-	ary2 = ary_new(rb_obj_class(ary), 0);
-	goto out;
+        ary2 = ary_new(rb_cArray, 0);
+        goto out;
     }
     if (len < 0) {
-	rb_raise(rb_eArgError, "negative argument");
+        rb_raise(rb_eArgError, "negative argument");
     }
     if (ARY_MAX_SIZE/len < RARRAY_LEN(ary)) {
-	rb_raise(rb_eArgError, "argument too big");
+        rb_raise(rb_eArgError, "argument too big");
     }
     len *= RARRAY_LEN(ary);
 
-    ary2 = ary_new(rb_obj_class(ary), len);
+    ary2 = ary_new(rb_cArray, len);
     ARY_SET_LEN(ary2, len);
 
-    ptr = RARRAY_CONST_PTR(ary);
+    ptr = RARRAY_CONST_PTR_TRANSIENT(ary);
     t = RARRAY_LEN(ary);
     if (0 < t) {
-	ary_memcpy(ary2, 0, t, ptr);
-	while (t <= len/2) {
-	    ary_memcpy(ary2, t, t, RARRAY_CONST_PTR(ary2));
+        ary_memcpy(ary2, 0, t, ptr);
+        while (t <= len/2) {
+            ary_memcpy(ary2, t, t, RARRAY_CONST_PTR_TRANSIENT(ary2));
             t *= 2;
         }
         if (t < len) {
-	    ary_memcpy(ary2, t, len-t, RARRAY_CONST_PTR(ary2));
+            ary_memcpy(ary2, t, len-t, RARRAY_CONST_PTR_TRANSIENT(ary2));
         }
     }
   out:
-    OBJ_INFECT(ary2, ary);
-
     return ary2;
 }
 
 /*
  *  call-seq:
- *     ary.assoc(obj)   -> new_ary  or  nil
+ *    array.assoc(obj) -> found_array or nil
  *
- *  Searches through an array whose elements are also arrays comparing +obj+
- *  with the first element of each contained array using <code>obj.==</code>.
+ *  Returns the first element in +self+ that is an \Array
+ *  whose first element <tt>==</tt> +obj+:
  *
- *  Returns the first contained array that matches (that is, the first
- *  associated array), or +nil+ if no match is found.
+ *    a = [{foo: 0}, [2, 4], [4, 5, 6], [4, 5]]
+ *    a.assoc(4) # => [4, 5, 6]
  *
- *  See also Array#rassoc
+ *  Returns +nil+ if no such element is found.
  *
- *     s1 = [ "colors", "red", "blue", "green" ]
- *     s2 = [ "letters", "a", "b", "c" ]
- *     s3 = "foo"
- *     a  = [ s1, s2, s3 ]
- *     a.assoc("letters")  #=> [ "letters", "a", "b", "c" ]
- *     a.assoc("foo")      #=> nil
+ *  Related: #rassoc.
  */
 
 VALUE
@@ -3651,30 +5231,27 @@ rb_ary_assoc(VALUE ary, VALUE key)
     VALUE v;
 
     for (i = 0; i < RARRAY_LEN(ary); ++i) {
-	v = rb_check_array_type(RARRAY_AREF(ary, i));
-	if (!NIL_P(v) && RARRAY_LEN(v) > 0 &&
-	    rb_equal(RARRAY_AREF(v, 0), key))
-	    return v;
+        v = rb_check_array_type(RARRAY_AREF(ary, i));
+        if (!NIL_P(v) && RARRAY_LEN(v) > 0 &&
+            rb_equal(RARRAY_AREF(v, 0), key))
+            return v;
     }
     return Qnil;
 }
 
 /*
  *  call-seq:
- *     ary.rassoc(obj) -> new_ary or nil
+ *    array.rassoc(obj) -> found_array or nil
  *
- *  Searches through the array whose elements are also arrays.
+ *  Returns the first element in +self+ that is an \Array
+ *  whose second element <tt>==</tt> +obj+:
  *
- *  Compares +obj+ with the second element of each contained array using
- *  <code>obj.==</code>.
+ *    a = [{foo: 0}, [2, 4], [4, 5, 6], [4, 5]]
+ *    a.rassoc(4) # => [2, 4]
  *
- *  Returns the first contained array that matches +obj+.
+ *  Returns +nil+ if no such element is found.
  *
- *  See also Array#assoc.
- *
- *     a = [ [ 1, "one"], [2, "two"], [3, "three"], ["ii", "two"] ]
- *     a.rassoc("two")    #=> [2, "two"]
- *     a.rassoc("four")   #=> nil
+ *  Related: #assoc.
  */
 
 VALUE
@@ -3684,11 +5261,11 @@ rb_ary_rassoc(VALUE ary, VALUE value)
     VALUE v;
 
     for (i = 0; i < RARRAY_LEN(ary); ++i) {
-	v = RARRAY_AREF(ary, i);
-	if (RB_TYPE_P(v, T_ARRAY) &&
-	    RARRAY_LEN(v) > 1 &&
-	    rb_equal(RARRAY_AREF(v, 1), value))
-	    return v;
+        v = RARRAY_AREF(ary, i);
+        if (RB_TYPE_P(v, T_ARRAY) &&
+            RARRAY_LEN(v) > 1 &&
+            rb_equal(RARRAY_AREF(v, 1), value))
+            return v;
     }
     return Qnil;
 }
@@ -3701,43 +5278,48 @@ recursive_equal(VALUE ary1, VALUE ary2, int recur)
 
     if (recur) return Qtrue; /* Subtle! */
 
+    /* rb_equal() can evacuate ptrs */
     p1 = RARRAY_CONST_PTR(ary1);
     p2 = RARRAY_CONST_PTR(ary2);
     len1 = RARRAY_LEN(ary1);
 
     for (i = 0; i < len1; i++) {
-	if (*p1 != *p2) {
-	    if (rb_equal(*p1, *p2)) {
-		len1 = RARRAY_LEN(ary1);
-		if (len1 != RARRAY_LEN(ary2))
-		    return Qfalse;
-		if (len1 < i)
-		    return Qtrue;
-		p1 = RARRAY_CONST_PTR(ary1) + i;
-		p2 = RARRAY_CONST_PTR(ary2) + i;
-	    }
-	    else {
-		return Qfalse;
-	    }
-	}
-	p1++;
-	p2++;
+        if (*p1 != *p2) {
+            if (rb_equal(*p1, *p2)) {
+                len1 = RARRAY_LEN(ary1);
+                if (len1 != RARRAY_LEN(ary2))
+                    return Qfalse;
+                if (len1 < i)
+                    return Qtrue;
+                p1 = RARRAY_CONST_PTR(ary1) + i;
+                p2 = RARRAY_CONST_PTR(ary2) + i;
+            }
+            else {
+                return Qfalse;
+            }
+        }
+        p1++;
+        p2++;
     }
     return Qtrue;
 }
 
 /*
  *  call-seq:
- *     ary == other_ary   ->   bool
+ *    array == other_array -> true or false
+ *
+ *  Returns +true+ if both <tt>array.size == other_array.size</tt>
+ *  and for each index +i+ in +array+, <tt>array[i] == other_array[i]</tt>:
  *
- *  Equality --- Two arrays are equal if they contain the same number of
- *  elements and if each element is equal to (according to Object#==) the
- *  corresponding element in +other_ary+.
+ *    a0 = [:foo, 'bar', 2]
+ *    a1 = [:foo, 'bar', 2.0]
+ *    a1 == a0 # => true
+ *    [] == [] # => true
  *
- *     [ "a", "c" ]    == [ "a", "c", 7 ]     #=> false
- *     [ "a", "c", 7 ] == [ "a", "c", 7 ]     #=> true
- *     [ "a", "c", 7 ] == [ "a", "d", "f" ]   #=> false
+ *  Otherwise, returns +false+.
  *
+ *  This method is different from method Array#eql?,
+ *  which compares elements using <tt>Object#eql?</tt>.
  */
 
 static VALUE
@@ -3745,13 +5327,13 @@ rb_ary_equal(VALUE ary1, VALUE ary2)
 {
     if (ary1 == ary2) return Qtrue;
     if (!RB_TYPE_P(ary2, T_ARRAY)) {
-	if (!rb_respond_to(ary2, rb_intern("to_ary"))) {
-	    return Qfalse;
-	}
-	return rb_equal(ary2, ary1);
+        if (!rb_respond_to(ary2, idTo_ary)) {
+            return Qfalse;
+        }
+        return rb_equal(ary2, ary1);
     }
     if (RARRAY_LEN(ary1) != RARRAY_LEN(ary2)) return Qfalse;
-    if (RARRAY_CONST_PTR(ary1) == RARRAY_CONST_PTR(ary2)) return Qtrue;
+    if (RARRAY_CONST_PTR_TRANSIENT(ary1) == RARRAY_CONST_PTR_TRANSIENT(ary2)) return Qtrue;
     return rb_exec_recursive_paired(recursive_equal, ary1, ary2, ary2);
 }
 
@@ -3762,18 +5344,27 @@ recursive_eql(VALUE ary1, VALUE ary2, int recur)
 
     if (recur) return Qtrue; /* Subtle! */
     for (i=0; i<RARRAY_LEN(ary1); i++) {
-	if (!rb_eql(rb_ary_elt(ary1, i), rb_ary_elt(ary2, i)))
-	    return Qfalse;
+        if (!rb_eql(rb_ary_elt(ary1, i), rb_ary_elt(ary2, i)))
+            return Qfalse;
     }
     return Qtrue;
 }
 
 /*
  *  call-seq:
- *     ary.eql?(other)  -> true or false
+ *    array.eql? other_array -> true or false
+ *
+ *  Returns +true+ if +self+ and +other_array+ are the same size,
+ *  and if, for each index +i+ in +self+, <tt>self[i].eql? other_array[i]</tt>:
+ *
+ *    a0 = [:foo, 'bar', 2]
+ *    a1 = [:foo, 'bar', 2]
+ *    a1.eql?(a0) # => true
+ *
+ *  Otherwise, returns +false+.
  *
- *  Returns +true+ if +self+ and +other+ are the same object,
- *  or are both arrays with the same content (according to Object#eql?).
+ *  This method is different from method Array#==,
+ *  which compares using method <tt>Object#==</tt>.
  */
 
 static VALUE
@@ -3782,18 +5373,21 @@ rb_ary_eql(VALUE ary1, VALUE ary2)
     if (ary1 == ary2) return Qtrue;
     if (!RB_TYPE_P(ary2, T_ARRAY)) return Qfalse;
     if (RARRAY_LEN(ary1) != RARRAY_LEN(ary2)) return Qfalse;
-    if (RARRAY_CONST_PTR(ary1) == RARRAY_CONST_PTR(ary2)) return Qtrue;
+    if (RARRAY_CONST_PTR_TRANSIENT(ary1) == RARRAY_CONST_PTR_TRANSIENT(ary2)) return Qtrue;
     return rb_exec_recursive_paired(recursive_eql, ary1, ary2, ary2);
 }
 
 /*
  *  call-seq:
- *     ary.hash   -> fixnum
+ *    array.hash -> integer
  *
- *  Compute a hash-code for this array.
+ *  Returns the integer hash value for +self+.
+ *
+ *  Two arrays with the same content will have the same hash code (and will compare using eql?):
+ *
+ *    [0, 1, 2].hash == [0, 1, 2].hash # => true
+ *    [0, 1, 2].hash == [0, 1, 3].hash # => false
  *
- *  Two arrays with the same content will have the same hash code (and will
- *  compare using #eql?).
  */
 
 static VALUE
@@ -3806,38 +5400,53 @@ rb_ary_hash(VALUE ary)
     h = rb_hash_start(RARRAY_LEN(ary));
     h = rb_hash_uint(h, (st_index_t)rb_ary_hash);
     for (i=0; i<RARRAY_LEN(ary); i++) {
-	n = rb_hash(RARRAY_AREF(ary, i));
-	h = rb_hash_uint(h, NUM2LONG(n));
+        n = rb_hash(RARRAY_AREF(ary, i));
+        h = rb_hash_uint(h, NUM2LONG(n));
     }
     h = rb_hash_end(h);
-    return LONG2FIX(h);
+    return ST2FIX(h);
 }
 
 /*
  *  call-seq:
- *     ary.include?(object)   -> true or false
+ *    array.include?(obj) -> true or false
  *
- *  Returns +true+ if the given +object+ is present in +self+ (that is, if any
- *  element <code>==</code> +object+), otherwise returns +false+.
+ *  Returns +true+ if for some index +i+ in +self+, <tt>obj == self[i]</tt>;
+ *  otherwise +false+:
  *
- *     a = [ "a", "b", "c" ]
- *     a.include?("b")   #=> true
- *     a.include?("z")   #=> false
+ *    [0, 1, 2].include?(2) # => true
+ *    [0, 1, 2].include?(3) # => false
  */
 
 VALUE
 rb_ary_includes(VALUE ary, VALUE item)
 {
     long i;
+    VALUE e;
 
     for (i=0; i<RARRAY_LEN(ary); i++) {
-	if (rb_equal(RARRAY_AREF(ary, i), item)) {
-	    return Qtrue;
-	}
+        e = RARRAY_AREF(ary, i);
+        if (rb_equal(e, item)) {
+            return Qtrue;
+        }
     }
     return Qfalse;
 }
 
+static VALUE
+rb_ary_includes_by_eql(VALUE ary, VALUE item)
+{
+    long i;
+    VALUE e;
+
+    for (i=0; i<RARRAY_LEN(ary); i++) {
+        e = RARRAY_AREF(ary, i);
+        if (rb_eql(item, e)) {
+            return Qtrue;
+        }
+    }
+    return Qfalse;
+}
 
 static VALUE
 recursive_cmp(VALUE ary1, VALUE ary2, int recur)
@@ -3847,45 +5456,46 @@ recursive_cmp(VALUE ary1, VALUE ary2, int recur)
     if (recur) return Qundef;	/* Subtle! */
     len = RARRAY_LEN(ary1);
     if (len > RARRAY_LEN(ary2)) {
-	len = RARRAY_LEN(ary2);
+        len = RARRAY_LEN(ary2);
     }
     for (i=0; i<len; i++) {
-	VALUE e1 = rb_ary_elt(ary1, i), e2 = rb_ary_elt(ary2, i);
-	VALUE v = rb_funcallv(e1, id_cmp, 1, &e2);
-	if (v != INT2FIX(0)) {
-	    return v;
-	}
+        VALUE e1 = rb_ary_elt(ary1, i), e2 = rb_ary_elt(ary2, i);
+        VALUE v = rb_funcallv(e1, id_cmp, 1, &e2);
+        if (v != INT2FIX(0)) {
+            return v;
+        }
     }
     return Qundef;
 }
 
 /*
  *  call-seq:
- *     ary <=> other_ary   ->  -1, 0, +1 or nil
+ *    array <=> other_array -> -1, 0, or 1
+ *
+ *  Returns -1, 0, or 1 as +self+ is less than, equal to, or greater than +other_array+.
+ *  For each index +i+ in +self+, evaluates <tt>result = self[i] <=> other_array[i]</tt>.
+ *
+ *  Returns -1 if any result is -1:
  *
- *  Comparison --- Returns an integer (+-1+, +0+, or <code>+1</code>) if this
- *  array is less than, equal to, or greater than +other_ary+.
+ *    [0, 1, 2] <=> [0, 1, 3] # => -1
  *
- *  Each object in each array is compared (using the <=> operator).
+ *  Returns 1 if any result is 1:
  *
- *  Arrays are compared in an "element-wise" manner; the first element of +ary+
- *  is compared with the first one of +other_ary+ using the <=> operator, then
- *  each of the second elements, etc...
- *  As soon as the result of any such comparison is non zero (i.e. the two
- *  corresponding elements are not equal), that result is returned for the
- *  whole array comparison.
+ *    [0, 1, 2] <=> [0, 1, 1] # => 1
  *
- *  If all the elements are equal, then the result is based on a comparison of
- *  the array lengths. Thus, two arrays are "equal" according to Array#<=> if,
- *  and only if, they have the same length and the value of each element is
- *  equal to the value of the corresponding element in the other array.
+ *  When all results are zero:
  *
- *  +nil+ is returned if the +other_ary+ is not an array or if the comparison
- *  of two elements returned +nil+.
+ *  - Returns -1 if +array+ is smaller than +other_array+:
  *
- *     [ "a", "a", "c" ]    <=> [ "a", "b", "c" ]   #=> -1
- *     [ 1, 2, 3, 4, 5, 6 ] <=> [ 1, 2 ]            #=> +1
- *     [ 1, 2 ]             <=> [ 1, :two ]         #=> nil
+ *      [0, 1, 2] <=> [0, 1, 2, 3] # => -1
+ *
+ *  - Returns 1 if +array+ is larger than +other_array+:
+ *
+ *      [0, 1, 2] <=> [0, 1] # => 1
+ *
+ *  - Returns 0 if +array+ and +other_array+ are the same size:
+ *
+ *      [0, 1, 2] <=> [0, 1, 2] # => 0
  *
  */
 
@@ -3899,7 +5509,7 @@ rb_ary_cmp(VALUE ary1, VALUE ary2)
     if (NIL_P(ary2)) return Qnil;
     if (ary1 == ary2) return INT2FIX(0);
     v = rb_exec_recursive_paired(recursive_cmp, ary1, ary2, ary2);
-    if (v != Qundef) return v;
+    if (!UNDEF_P(v)) return v;
     len = RARRAY_LEN(ary1) - RARRAY_LEN(ary2);
     if (len == 0) return INT2FIX(0);
     if (len > 0) return INT2FIX(1);
@@ -3912,18 +5522,17 @@ ary_add_hash(VALUE hash, VALUE ary)
     long i;
 
     for (i=0; i<RARRAY_LEN(ary); i++) {
-	VALUE elt = RARRAY_AREF(ary, i);
-	if (rb_hash_lookup2(hash, elt, Qundef) == Qundef) {
-	    rb_hash_aset(hash, elt, elt);
-	}
+        VALUE elt = RARRAY_AREF(ary, i);
+        rb_hash_add_new_element(hash, elt, elt);
     }
     return hash;
 }
 
 static inline VALUE
-ary_tmp_hash_new(void)
+ary_tmp_hash_new(VALUE ary)
 {
-    VALUE hash = rb_hash_new();
+    long size = RARRAY_LEN(ary);
+    VALUE hash = rb_hash_new_with_size(size);
 
     RBASIC_CLEAR_CLASS(hash);
     return hash;
@@ -3932,7 +5541,7 @@ ary_tmp_hash_new(void)
 static VALUE
 ary_make_hash(VALUE ary)
 {
-    VALUE hash = ary_tmp_hash_new();
+    VALUE hash = ary_tmp_hash_new(ary);
     return ary_add_hash(hash, ary);
 }
 
@@ -3942,10 +5551,8 @@ ary_add_hash_by(VALUE hash, VALUE ary)
     long i;
 
     for (i = 0; i < RARRAY_LEN(ary); ++i) {
-	VALUE v = rb_ary_elt(ary, i), k = rb_yield(v);
-	if (rb_hash_lookup2(hash, k, Qundef) == Qundef) {
-	    rb_hash_aset(hash, k, v);
-	}
+        VALUE v = rb_ary_elt(ary, i), k = rb_yield(v);
+        rb_hash_add_new_element(hash, k, v);
     }
     return hash;
 }
@@ -3953,50 +5560,61 @@ ary_add_hash_by(VALUE hash, VALUE ary)
 static VALUE
 ary_make_hash_by(VALUE ary)
 {
-    VALUE hash = ary_tmp_hash_new();
+    VALUE hash = ary_tmp_hash_new(ary);
     return ary_add_hash_by(hash, ary);
 }
 
 static inline void
 ary_recycle_hash(VALUE hash)
 {
-    if (RHASH(hash)->ntbl) {
-	st_table *tbl = RHASH(hash)->ntbl;
-	RHASH(hash)->ntbl = 0;
-	st_free_table(tbl);
+    assert(RBASIC_CLASS(hash) == 0);
+    if (RHASH_ST_TABLE_P(hash)) {
+        st_table *tbl = RHASH_ST_TABLE(hash);
+        st_free_table(tbl);
+        RHASH_ST_CLEAR(hash);
     }
 }
 
 /*
  *  call-seq:
- *     ary - other_ary    -> new_ary
+ *    array - other_array -> new_array
  *
- *  Array Difference
+ *  Returns a new \Array containing only those elements from +array+
+ *  that are not found in \Array +other_array+;
+ *  items are compared using <tt>eql?</tt>;
+ *  the order from +array+ is preserved:
  *
- *  Returns a new array that is a copy of the original array, removing any
- *  items that also appear in +other_ary+. The order is preserved from the
- *  original array.
+ *    [0, 1, 1, 2, 1, 1, 3, 1, 1] - [1] # => [0, 2, 3]
+ *    [0, 1, 2, 3] - [3, 0] # => [1, 2]
+ *    [0, 1, 2] - [4] # => [0, 1, 2]
  *
- *  It compares elements using their #hash and #eql? methods for efficiency.
- *
- *     [ 1, 1, 2, 2, 3, 3, 4, 5 ] - [ 1, 2, 4 ]  #=>  [ 3, 3, 5 ]
- *
- *  If you need set-like behavior, see the library class Set.
+ *  Related: Array#difference.
  */
 
-static VALUE
+VALUE
 rb_ary_diff(VALUE ary1, VALUE ary2)
 {
     VALUE ary3;
-    volatile VALUE hash;
+    VALUE hash;
     long i;
 
-    hash = ary_make_hash(to_ary(ary2));
+    ary2 = to_ary(ary2);
+    if (RARRAY_LEN(ary2) == 0) { return ary_make_shared_copy(ary1); }
     ary3 = rb_ary_new();
 
+    if (RARRAY_LEN(ary1) <= SMALL_ARRAY_LEN || RARRAY_LEN(ary2) <= SMALL_ARRAY_LEN) {
+        for (i=0; i<RARRAY_LEN(ary1); i++) {
+            VALUE elt = rb_ary_elt(ary1, i);
+            if (rb_ary_includes_by_eql(ary2, elt)) continue;
+            rb_ary_push(ary3, elt);
+        }
+        return ary3;
+    }
+
+    hash = ary_make_hash(ary2);
     for (i=0; i<RARRAY_LEN(ary1); i++) {
-	if (st_lookup(rb_hash_tbl_raw(hash), RARRAY_AREF(ary1, i), 0)) continue;
-	rb_ary_push(ary3, rb_ary_elt(ary1, i));
+        if (rb_hash_stlike_lookup(hash, RARRAY_AREF(ary1, i), NULL)) continue;
+        rb_ary_push(ary3, rb_ary_elt(ary1, i));
     }
     ary_recycle_hash(hash);
     return ary3;
@@ -4004,18 +5622,73 @@ rb_ary_diff(VALUE ary1, VALUE ary2)
 
 /*
  *  call-seq:
- *     ary & other_ary      -> new_ary
+ *    array.difference(*other_arrays) -> new_array
+ *
+ *  Returns a new \Array containing only those elements from +self+
+ *  that are not found in any of the Arrays +other_arrays+;
+ *  items are compared using <tt>eql?</tt>;  order from +self+ is preserved:
+ *
+ *    [0, 1, 1, 2, 1, 1, 3, 1, 1].difference([1]) # => [0, 2, 3]
+ *    [0, 1, 2, 3].difference([3, 0], [1, 3]) # => [2]
+ *    [0, 1, 2].difference([4]) # => [0, 1, 2]
+ *
+ *  Returns a copy of +self+ if no arguments given.
+ *
+ *  Related: Array#-.
+ */
+
+static VALUE
+rb_ary_difference_multi(int argc, VALUE *argv, VALUE ary)
+{
+    VALUE ary_diff;
+    long i, length;
+    volatile VALUE t0;
+    bool *is_hash = ALLOCV_N(bool, t0, argc);
+    ary_diff = rb_ary_new();
+    length = RARRAY_LEN(ary);
+
+    for (i = 0; i < argc; i++) {
+        argv[i] = to_ary(argv[i]);
+        is_hash[i] = (length > SMALL_ARRAY_LEN && RARRAY_LEN(argv[i]) > SMALL_ARRAY_LEN);
+        if (is_hash[i]) argv[i] = ary_make_hash(argv[i]);
+    }
+
+    for (i = 0; i < RARRAY_LEN(ary); i++) {
+        int j;
+        VALUE elt = rb_ary_elt(ary, i);
+        for (j = 0; j < argc; j++) {
+            if (is_hash[j]) {
+                if (rb_hash_stlike_lookup(argv[j], RARRAY_AREF(ary, i), NULL))
+                    break;
+            }
+            else {
+                if (rb_ary_includes_by_eql(argv[j], elt)) break;
+            }
+        }
+        if (j == argc) rb_ary_push(ary_diff, elt);
+    }
+
+    ALLOCV_END(t0);
+
+    return ary_diff;
+}
+
+
+/*
+ *  call-seq:
+ *    array & other_array -> new_array
  *
- *  Set Intersection --- Returns a new array containing elements common to the
- *  two arrays, excluding any duplicates. The order is preserved from the
- *  original array.
+ *  Returns a new \Array containing each element found in both +array+ and \Array +other_array+;
+ *  duplicates are omitted; items are compared using <tt>eql?</tt>:
  *
- *  It compares elements using their #hash and #eql? methods for efficiency.
+ *    [0, 1, 2, 3] & [1, 2] # => [1, 2]
+ *    [0, 1, 0, 1] & [0, 1] # => [0, 1]
  *
- *     [ 1, 1, 3, 5 ] & [ 1, 2, 3 ]                 #=> [ 1, 3 ]
- *     [ 'a', 'b', 'b', 'z' ] & [ 'a', 'b', 'c' ]   #=> [ 'a', 'b' ]
+ *  Preserves order from +array+:
  *
- *  See also Array#uniq.
+ *    [0, 1, 2] & [3, 2, 1, 0] # => [0, 1, 2]
+ *
+ *  Related: Array#intersection.
  */
 
 
@@ -4023,28 +5696,70 @@ static VALUE
 rb_ary_and(VALUE ary1, VALUE ary2)
 {
     VALUE hash, ary3, v;
-    st_table *table;
     st_data_t vv;
     long i;
 
     ary2 = to_ary(ary2);
     ary3 = rb_ary_new();
-    if (RARRAY_LEN(ary2) == 0) return ary3;
+    if (RARRAY_LEN(ary1) == 0 || RARRAY_LEN(ary2) == 0) return ary3;
+
+    if (RARRAY_LEN(ary1) <= SMALL_ARRAY_LEN && RARRAY_LEN(ary2) <= SMALL_ARRAY_LEN) {
+        for (i=0; i<RARRAY_LEN(ary1); i++) {
+            v = RARRAY_AREF(ary1, i);
+            if (!rb_ary_includes_by_eql(ary2, v)) continue;
+            if (rb_ary_includes_by_eql(ary3, v)) continue;
+            rb_ary_push(ary3, v);
+        }
+        return ary3;
+    }
+
     hash = ary_make_hash(ary2);
-    table = rb_hash_tbl_raw(hash);
 
     for (i=0; i<RARRAY_LEN(ary1); i++) {
-	v = RARRAY_AREF(ary1, i);
-	vv = (st_data_t)v;
-	if (st_delete(table, &vv, 0)) {
-	    rb_ary_push(ary3, v);
-	}
+        v = RARRAY_AREF(ary1, i);
+        vv = (st_data_t)v;
+        if (rb_hash_stlike_delete(hash, &vv, 0)) {
+            rb_ary_push(ary3, v);
+        }
     }
     ary_recycle_hash(hash);
 
     return ary3;
 }
 
+/*
+ *  call-seq:
+ *    array.intersection(*other_arrays) -> new_array
+ *
+ *  Returns a new \Array containing each element found both in +self+
+ *  and in all of the given Arrays +other_arrays+;
+ *  duplicates are omitted; items are compared using <tt>eql?</tt>:
+ *
+ *    [0, 1, 2, 3].intersection([0, 1, 2], [0, 1, 3]) # => [0, 1]
+ *    [0, 0, 1, 1, 2, 3].intersection([0, 1, 2], [0, 1, 3]) # => [0, 1]
+ *
+ *  Preserves order from +self+:
+ *
+ *    [0, 1, 2].intersection([2, 1, 0]) # => [0, 1, 2]
+ *
+ *  Returns a copy of +self+ if no arguments given.
+ *
+ *  Related: Array#&.
+ */
+
+static VALUE
+rb_ary_intersection_multi(int argc, VALUE *argv, VALUE ary)
+{
+    VALUE result = rb_ary_dup(ary);
+    int i;
+
+    for (i = 0; i < argc; i++) {
+        result = rb_ary_and(result, argv[i]);
+    }
+
+    return result;
+}
+
 static int
 ary_hash_orset(st_data_t *key, st_data_t *value, st_data_t arg, int existing)
 {
@@ -4053,40 +5768,535 @@ ary_hash_orset(st_data_t *key, st_data_t *value, st_data_t arg, int existing)
     return ST_CONTINUE;
 }
 
+static void
+rb_ary_union(VALUE ary_union, VALUE ary)
+{
+    long i;
+    for (i = 0; i < RARRAY_LEN(ary); i++) {
+        VALUE elt = rb_ary_elt(ary, i);
+        if (rb_ary_includes_by_eql(ary_union, elt)) continue;
+        rb_ary_push(ary_union, elt);
+    }
+}
+
+static void
+rb_ary_union_hash(VALUE hash, VALUE ary2)
+{
+    long i;
+    for (i = 0; i < RARRAY_LEN(ary2); i++) {
+        VALUE elt = RARRAY_AREF(ary2, i);
+        if (!rb_hash_stlike_update(hash, (st_data_t)elt, ary_hash_orset, (st_data_t)elt)) {
+            RB_OBJ_WRITTEN(hash, Qundef, elt);
+        }
+    }
+}
+
 /*
  *  call-seq:
- *     ary | other_ary     -> new_ary
+ *    array | other_array -> new_array
  *
- *  Set Union --- Returns a new array by joining +ary+ with +other_ary+,
- *  excluding any duplicates and preserving the order from the original array.
+ *  Returns the union of +array+ and \Array +other_array+;
+ *  duplicates are removed; order is preserved;
+ *  items are compared using <tt>eql?</tt>:
  *
- *  It compares elements using their #hash and #eql? methods for efficiency.
+ *    [0, 1] | [2, 3] # => [0, 1, 2, 3]
+ *    [0, 1, 1] | [2, 2, 3] # => [0, 1, 2, 3]
+ *    [0, 1, 2] | [3, 2, 1, 0] # => [0, 1, 2, 3]
  *
- *     [ "a", "b", "c" ] | [ "c", "d", "a" ]    #=> [ "a", "b", "c", "d" ]
- *
- *  See also Array#uniq.
+ *  Related: Array#union.
  */
 
 static VALUE
 rb_ary_or(VALUE ary1, VALUE ary2)
 {
     VALUE hash, ary3;
-    long i;
 
     ary2 = to_ary(ary2);
+    if (RARRAY_LEN(ary1) + RARRAY_LEN(ary2) <= SMALL_ARRAY_LEN) {
+        ary3 = rb_ary_new();
+        rb_ary_union(ary3, ary1);
+        rb_ary_union(ary3, ary2);
+        return ary3;
+    }
+
     hash = ary_make_hash(ary1);
+    rb_ary_union_hash(hash, ary2);
 
-    for (i=0; i<RARRAY_LEN(ary2); i++) {
-	VALUE elt = RARRAY_AREF(ary2, i);
-	if (!st_update(RHASH_TBL_RAW(hash), (st_data_t)elt, ary_hash_orset, (st_data_t)elt)) {
-	    RB_OBJ_WRITTEN(hash, Qundef, elt);
-	}
-    }
     ary3 = rb_hash_values(hash);
     ary_recycle_hash(hash);
     return ary3;
 }
 
+/*
+ *  call-seq:
+ *    array.union(*other_arrays) -> new_array
+ *
+ *  Returns a new \Array that is the union of +self+ and all given Arrays +other_arrays+;
+ *  duplicates are removed;  order is preserved;  items are compared using <tt>eql?</tt>:
+ *
+ *    [0, 1, 2, 3].union([4, 5], [6, 7]) # => [0, 1, 2, 3, 4, 5, 6, 7]
+ *    [0, 1, 1].union([2, 1], [3, 1]) # => [0, 1, 2, 3]
+ *    [0, 1, 2, 3].union([3, 2], [1, 0]) # => [0, 1, 2, 3]
+ *
+ *  Returns a copy of +self+ if no arguments given.
+ *
+ *  Related: Array#|.
+ */
+
+static VALUE
+rb_ary_union_multi(int argc, VALUE *argv, VALUE ary)
+{
+    int i;
+    long sum;
+    VALUE hash, ary_union;
+
+    sum = RARRAY_LEN(ary);
+    for (i = 0; i < argc; i++) {
+        argv[i] = to_ary(argv[i]);
+        sum += RARRAY_LEN(argv[i]);
+    }
+
+    if (sum <= SMALL_ARRAY_LEN) {
+        ary_union = rb_ary_new();
+
+        rb_ary_union(ary_union, ary);
+        for (i = 0; i < argc; i++) rb_ary_union(ary_union, argv[i]);
+
+        return ary_union;
+    }
+
+    hash = ary_make_hash(ary);
+    for (i = 0; i < argc; i++) rb_ary_union_hash(hash, argv[i]);
+
+    ary_union = rb_hash_values(hash);
+    ary_recycle_hash(hash);
+    return ary_union;
+}
+
+/*
+ *  call-seq:
+ *     ary.intersect?(other_ary)   -> true or false
+ *
+ *  Returns +true+ if the array and +other_ary+ have at least one element in
+ *  common, otherwise returns +false+:
+ *
+ *     a = [ 1, 2, 3 ]
+ *     b = [ 3, 4, 5 ]
+ *     c = [ 5, 6, 7 ]
+ *     a.intersect?(b)   #=> true
+ *     a.intersect?(c)   #=> false
+ *
+ */
+
+static VALUE
+rb_ary_intersect_p(VALUE ary1, VALUE ary2)
+{
+    VALUE hash, v, result, shorter, longer;
+    st_data_t vv;
+    long i;
+
+    ary2 = to_ary(ary2);
+    if (RARRAY_LEN(ary1) == 0 || RARRAY_LEN(ary2) == 0) return Qfalse;
+
+    if (RARRAY_LEN(ary1) <= SMALL_ARRAY_LEN && RARRAY_LEN(ary2) <= SMALL_ARRAY_LEN) {
+        for (i=0; i<RARRAY_LEN(ary1); i++) {
+            v = RARRAY_AREF(ary1, i);
+            if (rb_ary_includes_by_eql(ary2, v)) return Qtrue;
+        }
+        return Qfalse;
+    }
+
+    shorter = ary1;
+    longer = ary2;
+    if (RARRAY_LEN(ary1) > RARRAY_LEN(ary2)) {
+        longer = ary1;
+        shorter = ary2;
+    }
+
+    hash = ary_make_hash(shorter);
+    result = Qfalse;
+
+    for (i=0; i<RARRAY_LEN(longer); i++) {
+        v = RARRAY_AREF(longer, i);
+        vv = (st_data_t)v;
+        if (rb_hash_stlike_lookup(hash, vv, 0)) {
+            result = Qtrue;
+            break;
+        }
+    }
+    ary_recycle_hash(hash);
+
+    return result;
+}
+
+static VALUE
+ary_max_generic(VALUE ary, long i, VALUE vmax)
+{
+    RUBY_ASSERT(i > 0 && i < RARRAY_LEN(ary));
+
+    VALUE v;
+    for (; i < RARRAY_LEN(ary); ++i) {
+        v = RARRAY_AREF(ary, i);
+
+        if (rb_cmpint(rb_funcallv(vmax, id_cmp, 1, &v), vmax, v) < 0) {
+            vmax = v;
+        }
+    }
+
+    return vmax;
+}
+
+static VALUE
+ary_max_opt_fixnum(VALUE ary, long i, VALUE vmax)
+{
+    const long n = RARRAY_LEN(ary);
+    RUBY_ASSERT(i > 0 && i < n);
+    RUBY_ASSERT(FIXNUM_P(vmax));
+
+    VALUE v;
+    for (; i < n; ++i) {
+        v = RARRAY_AREF(ary, i);
+
+        if (FIXNUM_P(v)) {
+            if ((long)vmax < (long)v) {
+                vmax = v;
+            }
+        }
+        else {
+            return ary_max_generic(ary, i, vmax);
+        }
+    }
+
+    return vmax;
+}
+
+static VALUE
+ary_max_opt_float(VALUE ary, long i, VALUE vmax)
+{
+    const long n = RARRAY_LEN(ary);
+    RUBY_ASSERT(i > 0 && i < n);
+    RUBY_ASSERT(RB_FLOAT_TYPE_P(vmax));
+
+    VALUE v;
+    for (; i < n; ++i) {
+        v = RARRAY_AREF(ary, i);
+
+        if (RB_FLOAT_TYPE_P(v)) {
+            if (rb_float_cmp(vmax, v) < 0) {
+                vmax = v;
+            }
+        }
+        else {
+            return ary_max_generic(ary, i, vmax);
+        }
+    }
+
+    return vmax;
+}
+
+static VALUE
+ary_max_opt_string(VALUE ary, long i, VALUE vmax)
+{
+    const long n = RARRAY_LEN(ary);
+    RUBY_ASSERT(i > 0 && i < n);
+    RUBY_ASSERT(STRING_P(vmax));
+
+    VALUE v;
+    for (; i < n; ++i) {
+        v = RARRAY_AREF(ary, i);
+
+        if (STRING_P(v)) {
+            if (rb_str_cmp(vmax, v) < 0) {
+                vmax = v;
+            }
+        }
+        else {
+            return ary_max_generic(ary, i, vmax);
+        }
+    }
+
+    return vmax;
+}
+
+/*
+ *  call-seq:
+ *    array.max -> element
+ *    array.max {|a, b| ... } -> element
+ *    array.max(n) -> new_array
+ *    array.max(n) {|a, b| ... } -> new_array
+ *
+ *  Returns one of the following:
+ *
+ *  - The maximum-valued element from +self+.
+ *  - A new \Array of maximum-valued elements selected from +self+.
+ *
+ *  When no block is given, each element in +self+ must respond to method <tt><=></tt>
+ *  with an \Integer.
+ *
+ *  With no argument and no block, returns the element in +self+
+ *  having the maximum value per method <tt><=></tt>:
+ *
+ *    [0, 1, 2].max # => 2
+ *
+ *  With an argument \Integer +n+ and no block, returns a new \Array with at most +n+ elements,
+ *  in descending order per method <tt><=></tt>:
+ *
+ *    [0, 1, 2, 3].max(3) # => [3, 2, 1]
+ *    [0, 1, 2, 3].max(6) # => [3, 2, 1, 0]
+ *
+ *  When a block is given, the block must return an \Integer.
+ *
+ *  With a block and no argument, calls the block <tt>self.size-1</tt> times to compare elements;
+ *  returns the element having the maximum value per the block:
+ *
+ *    ['0', '00', '000'].max {|a, b| a.size <=> b.size } # => "000"
+ *
+ *  With an argument +n+ and a block, returns a new \Array with at most +n+ elements,
+ *  in descending order per the block:
+ *
+ *    ['0', '00', '000'].max(2) {|a, b| a.size <=> b.size } # => ["000", "00"]
+ *
+ */
+static VALUE
+rb_ary_max(int argc, VALUE *argv, VALUE ary)
+{
+    VALUE result = Qundef, v;
+    VALUE num;
+    long i;
+
+    if (rb_check_arity(argc, 0, 1) && !NIL_P(num = argv[0]))
+       return rb_nmin_run(ary, num, 0, 1, 1);
+
+    const long n = RARRAY_LEN(ary);
+    if (rb_block_given_p()) {
+        for (i = 0; i < RARRAY_LEN(ary); i++) {
+           v = RARRAY_AREF(ary, i);
+           if (UNDEF_P(result) || rb_cmpint(rb_yield_values(2, v, result), v, result) > 0) {
+               result = v;
+           }
+        }
+    }
+    else if (n > 0) {
+        result = RARRAY_AREF(ary, 0);
+        if (n > 1) {
+            if (FIXNUM_P(result) && CMP_OPTIMIZABLE(INTEGER)) {
+                return ary_max_opt_fixnum(ary, 1, result);
+            }
+            else if (STRING_P(result) && CMP_OPTIMIZABLE(STRING)) {
+                return ary_max_opt_string(ary, 1, result);
+            }
+            else if (RB_FLOAT_TYPE_P(result) && CMP_OPTIMIZABLE(FLOAT)) {
+                return ary_max_opt_float(ary, 1, result);
+            }
+            else {
+                return ary_max_generic(ary, 1, result);
+            }
+        }
+    }
+    if (UNDEF_P(result)) return Qnil;
+    return result;
+}
+
+static VALUE
+ary_min_generic(VALUE ary, long i, VALUE vmin)
+{
+    RUBY_ASSERT(i > 0 && i < RARRAY_LEN(ary));
+
+    VALUE v;
+    for (; i < RARRAY_LEN(ary); ++i) {
+        v = RARRAY_AREF(ary, i);
+
+        if (rb_cmpint(rb_funcallv(vmin, id_cmp, 1, &v), vmin, v) > 0) {
+            vmin = v;
+        }
+    }
+
+    return vmin;
+}
+
+static VALUE
+ary_min_opt_fixnum(VALUE ary, long i, VALUE vmin)
+{
+    const long n = RARRAY_LEN(ary);
+    RUBY_ASSERT(i > 0 && i < n);
+    RUBY_ASSERT(FIXNUM_P(vmin));
+
+    VALUE a;
+    for (; i < n; ++i) {
+        a = RARRAY_AREF(ary, i);
+
+        if (FIXNUM_P(a)) {
+            if ((long)vmin > (long)a) {
+                vmin = a;
+            }
+        }
+        else {
+            return ary_min_generic(ary, i, vmin);
+        }
+    }
+
+    return vmin;
+}
+
+static VALUE
+ary_min_opt_float(VALUE ary, long i, VALUE vmin)
+{
+    const long n = RARRAY_LEN(ary);
+    RUBY_ASSERT(i > 0 && i < n);
+    RUBY_ASSERT(RB_FLOAT_TYPE_P(vmin));
+
+    VALUE a;
+    for (; i < n; ++i) {
+        a = RARRAY_AREF(ary, i);
+
+        if (RB_FLOAT_TYPE_P(a)) {
+            if (rb_float_cmp(vmin, a) > 0) {
+                vmin = a;
+            }
+        }
+        else {
+            return ary_min_generic(ary, i, vmin);
+        }
+    }
+
+    return vmin;
+}
+
+static VALUE
+ary_min_opt_string(VALUE ary, long i, VALUE vmin)
+{
+    const long n = RARRAY_LEN(ary);
+    RUBY_ASSERT(i > 0 && i < n);
+    RUBY_ASSERT(STRING_P(vmin));
+
+    VALUE a;
+    for (; i < n; ++i) {
+        a = RARRAY_AREF(ary, i);
+
+        if (STRING_P(a)) {
+            if (rb_str_cmp(vmin, a) > 0) {
+                vmin = a;
+            }
+        }
+        else {
+            return ary_min_generic(ary, i, vmin);
+        }
+    }
+
+    return vmin;
+}
+
+/*
+ *  call-seq:
+ *    array.min -> element
+ *    array.min { |a, b| ... } -> element
+ *    array.min(n) -> new_array
+ *    array.min(n) { |a, b| ... } -> new_array
+ *
+ *  Returns one of the following:
+ *
+ *  - The minimum-valued element from +self+.
+ *  - A new \Array of minimum-valued elements selected from +self+.
+ *
+ *  When no block is given, each element in +self+ must respond to method <tt><=></tt>
+ *  with an \Integer.
+ *
+ *  With no argument and no block, returns the element in +self+
+ *  having the minimum value per method <tt><=></tt>:
+ *
+ *    [0, 1, 2].min # => 0
+ *
+ *  With \Integer argument +n+ and no block, returns a new \Array with at most +n+ elements,
+ *  in ascending order per method <tt><=></tt>:
+ *
+ *    [0, 1, 2, 3].min(3) # => [0, 1, 2]
+ *    [0, 1, 2, 3].min(6) # => [0, 1, 2, 3]
+ *
+ *  When a block is given, the block must return an Integer.
+ *
+ *  With a block and no argument, calls the block <tt>self.size-1</tt> times to compare elements;
+ *  returns the element having the minimum value per the block:
+ *
+ *    ['0', '00', '000'].min { |a, b| a.size <=> b.size } # => "0"
+ *
+ *  With an argument +n+ and a block, returns a new \Array with at most +n+ elements,
+ *  in ascending order per the block:
+ *
+ *    ['0', '00', '000'].min(2) {|a, b| a.size <=> b.size } # => ["0", "00"]
+ *
+ */
+static VALUE
+rb_ary_min(int argc, VALUE *argv, VALUE ary)
+{
+    VALUE result = Qundef, v;
+    VALUE num;
+    long i;
+
+    if (rb_check_arity(argc, 0, 1) && !NIL_P(num = argv[0]))
+       return rb_nmin_run(ary, num, 0, 0, 1);
+
+    const long n = RARRAY_LEN(ary);
+    if (rb_block_given_p()) {
+        for (i = 0; i < RARRAY_LEN(ary); i++) {
+           v = RARRAY_AREF(ary, i);
+           if (UNDEF_P(result) || rb_cmpint(rb_yield_values(2, v, result), v, result) < 0) {
+               result = v;
+           }
+        }
+    }
+    else if (n > 0) {
+        result = RARRAY_AREF(ary, 0);
+        if (n > 1) {
+            if (FIXNUM_P(result) && CMP_OPTIMIZABLE(INTEGER)) {
+                return ary_min_opt_fixnum(ary, 1, result);
+            }
+            else if (STRING_P(result) && CMP_OPTIMIZABLE(STRING)) {
+                return ary_min_opt_string(ary, 1, result);
+            }
+            else if (RB_FLOAT_TYPE_P(result) && CMP_OPTIMIZABLE(FLOAT)) {
+                return ary_min_opt_float(ary, 1, result);
+            }
+            else {
+                return ary_min_generic(ary, 1, result);
+            }
+        }
+    }
+    if (UNDEF_P(result)) return Qnil;
+    return result;
+}
+
+/*
+ *  call-seq:
+ *    array.minmax -> [min_val, max_val]
+ *    array.minmax {|a, b| ... } -> [min_val, max_val]
+ *
+ *  Returns a new 2-element \Array containing the minimum and maximum values
+ *  from +self+, either per method <tt><=></tt> or per a given block:.
+ *
+ *  When no block is given, each element in +self+ must respond to method <tt><=></tt>
+ *  with an \Integer;
+ *  returns a new 2-element \Array containing the minimum and maximum values
+ *  from +self+, per method <tt><=></tt>:
+ *
+ *    [0, 1, 2].minmax # => [0, 2]
+ *
+ *  When a block is given, the block must return an \Integer;
+ *  the block is called <tt>self.size-1</tt> times to compare elements;
+ *  returns a new 2-element \Array containing the minimum and maximum values
+ *  from +self+, per the block:
+ *
+ *    ['0', '00', '000'].minmax {|a, b| a.size <=> b.size } # => ["0", "000"]
+ *
+ */
+static VALUE
+rb_ary_minmax(VALUE ary)
+{
+    if (rb_block_given_p()) {
+        return rb_call_super(0, NULL);
+    }
+    return rb_assoc_new(rb_ary_min(0, 0, ary), rb_ary_max(0, 0, ary));
+}
+
 static int
 push_value(st_data_t key, st_data_t val, st_data_t ary)
 {
@@ -4096,29 +6306,33 @@ push_value(st_data_t key, st_data_t val, st_data_t ary)
 
 /*
  *  call-seq:
- *     ary.uniq!                -> ary or nil
- *     ary.uniq! { |item| ... } -> ary or nil
+ *    array.uniq! -> self or nil
+ *    array.uniq! {|element| ... } -> self or nil
+ *
+ *  Removes duplicate elements from +self+, the first occurrence always being retained;
+ *  returns +self+ if any elements removed, +nil+ otherwise.
  *
- *  Removes duplicate elements from +self+.
+ *  With no block given, identifies and removes elements using method <tt>eql?</tt>
+ *  to compare.
  *
- *  If a block is given, it will use the return value of the block for
- *  comparison.
+ *  Returns +self+ if any elements removed:
  *
- *  It compares values using their #hash and #eql? methods for efficiency.
+ *    a = [0, 0, 1, 1, 2, 2]
+ *    a.uniq! # => [0, 1, 2]
  *
- *  Returns +nil+ if no changes are made (that is, no duplicates are found).
+ *  Returns +nil+ if no elements removed.
  *
- *     a = [ "a", "a", "b", "b", "c" ]
- *     a.uniq!   # => ["a", "b", "c"]
+ *  With a block given, calls the block for each element;
+ *  identifies (using method <tt>eql?</tt>) and removes
+ *  elements for which the block returns duplicate values.
  *
- *     b = [ "a", "b", "c" ]
- *     b.uniq!   # => nil
+ *  Returns +self+ if any elements removed:
  *
- *     c = [["student","sam"], ["student","george"], ["teacher","matz"]]
- *     c.uniq! { |s| s.first } # => [["student", "sam"], ["teacher", "matz"]]
+ *    a = ['a', 'aa', 'aaa', 'b', 'bb', 'bbb']
+ *    a.uniq! {|element| element.size } # => ['a', 'aa', 'aaa']
  *
+ *  Returns +nil+ if no elements removed.
  */
-
 static VALUE
 rb_ary_uniq_bang(VALUE ary)
 {
@@ -4129,22 +6343,22 @@ rb_ary_uniq_bang(VALUE ary)
     if (RARRAY_LEN(ary) <= 1)
         return Qnil;
     if (rb_block_given_p())
-	hash = ary_make_hash_by(ary);
+        hash = ary_make_hash_by(ary);
     else
-	hash = ary_make_hash(ary);
+        hash = ary_make_hash(ary);
 
     hash_size = RHASH_SIZE(hash);
     if (RARRAY_LEN(ary) == hash_size) {
-	return Qnil;
+        return Qnil;
     }
     rb_ary_modify_check(ary);
     ARY_SET_LEN(ary, 0);
     if (ARY_SHARED_P(ary) && !ARY_EMBED_P(ary)) {
-	rb_ary_unshare(ary);
-	FL_SET_EMBED(ary);
+        rb_ary_unshare(ary);
+        FL_SET_EMBED(ary);
     }
     ary_resize_capa(ary, hash_size);
-    st_foreach(rb_hash_tbl_raw(hash), push_value, ary);
+    rb_hash_foreach(hash, push_value, ary);
     ary_recycle_hash(hash);
 
     return ary;
@@ -4152,20 +6366,24 @@ rb_ary_uniq_bang(VALUE ary)
 
 /*
  *  call-seq:
- *     ary.uniq                -> new_ary
- *     ary.uniq { |item| ... } -> new_ary
+ *    array.uniq -> new_array
+ *    array.uniq {|element| ... } -> new_array
  *
- *  Returns a new array by removing duplicate values in +self+.
+ *  Returns a new \Array containing those elements from +self+ that are not duplicates,
+ *  the first occurrence always being retained.
  *
- *  If a block is given, it will use the return value of the block for comparison.
+ *  With no block given, identifies and omits duplicates using method <tt>eql?</tt>
+ *  to compare:
  *
- *  It compares values using their #hash and #eql? methods for efficiency.
+ *    a = [0, 0, 1, 1, 2, 2]
+ *    a.uniq # => [0, 1, 2]
  *
- *     a = [ "a", "a", "b", "b", "c" ]
- *     a.uniq   # => ["a", "b", "c"]
+ *  With a block given, calls the block for each element;
+ *  identifies (using method <tt>eql?</tt>) and omits duplicate values,
+ *  that is, those elements for which the block returns the same value:
  *
- *     b = [["student","sam"], ["student","george"], ["teacher","matz"]]
- *     b.uniq { |s| s.first } # => [["student", "sam"], ["teacher", "matz"]]
+ *    a = ['a', 'aa', 'aaa', 'b', 'bb', 'bbb']
+ *    a.uniq {|element| element.size } # => ["a", "aa", "aaa"]
  *
  */
 
@@ -4174,32 +6392,32 @@ rb_ary_uniq(VALUE ary)
 {
     VALUE hash, uniq;
 
-    if (RARRAY_LEN(ary) <= 1)
-        return rb_ary_dup(ary);
-    if (rb_block_given_p()) {
-	hash = ary_make_hash_by(ary);
-	uniq = rb_hash_values(hash);
+    if (RARRAY_LEN(ary) <= 1) {
+        hash = 0;
+        uniq = rb_ary_dup(ary);
+    }
+    else if (rb_block_given_p()) {
+        hash = ary_make_hash_by(ary);
+        uniq = rb_hash_values(hash);
     }
     else {
-	hash = ary_make_hash(ary);
-	uniq = rb_hash_values(hash);
+        hash = ary_make_hash(ary);
+        uniq = rb_hash_values(hash);
+    }
+    if (hash) {
+        ary_recycle_hash(hash);
     }
-    RBASIC_SET_CLASS(uniq, rb_obj_class(ary));
-    ary_recycle_hash(hash);
 
     return uniq;
 }
 
 /*
  *  call-seq:
- *     ary.compact!    -> ary  or  nil
+ *    array.compact! -> self or nil
  *
- *  Removes +nil+ elements from the array.
+ *  Removes all +nil+ elements from +self+.
  *
- *  Returns +nil+ if no changes were made, otherwise returns the array.
- *
- *     [ "a", nil, "b", nil, "c" ].compact! #=> [ "a", "b", "c" ]
- *     [ "a", "b", "c" ].compact!           #=> nil
+ *  Returns +self+ if any elements removed, otherwise +nil+.
  */
 
 static VALUE
@@ -4209,16 +6427,16 @@ rb_ary_compact_bang(VALUE ary)
     long n;
 
     rb_ary_modify(ary);
-    p = t = (VALUE *)RARRAY_CONST_PTR(ary); /* WB: no new reference */
+    p = t = (VALUE *)RARRAY_CONST_PTR_TRANSIENT(ary); /* WB: no new reference */
     end = p + RARRAY_LEN(ary);
 
     while (t < end) {
-	if (NIL_P(*t)) t++;
-	else *p++ = *t++;
+        if (NIL_P(*t)) t++;
+        else *p++ = *t++;
     }
-    n = p - RARRAY_CONST_PTR(ary);
+    n = p - RARRAY_CONST_PTR_TRANSIENT(ary);
     if (RARRAY_LEN(ary) == n) {
-	return Qnil;
+        return Qnil;
     }
     ary_resize_smaller(ary, n);
 
@@ -4227,12 +6445,12 @@ rb_ary_compact_bang(VALUE ary)
 
 /*
  *  call-seq:
- *     ary.compact     -> new_ary
+ *    array.compact -> new_array
  *
- *  Returns a copy of +self+ with all +nil+ elements removed.
+ *  Returns a new \Array containing all non-+nil+ elements from +self+:
  *
- *     [ "a", nil, "b", nil, "c", nil ].compact
- *                       #=> [ "a", "b", "c" ]
+ *    a = [nil, 0, nil, 1, nil, 2, nil]
+ *    a.compact # => [0, 1, 2]
  */
 
 static VALUE
@@ -4245,23 +6463,29 @@ rb_ary_compact(VALUE ary)
 
 /*
  *  call-seq:
- *     ary.count                   -> int
- *     ary.count(obj)              -> int
- *     ary.count { |item| block }  -> int
+ *    array.count -> an_integer
+ *    array.count(obj) -> an_integer
+ *    array.count {|element| ... } -> an_integer
+ *
+ *  Returns a count of specified elements.
+ *
+ *  With no argument and no block, returns the count of all elements:
  *
- *  Returns the number of elements.
+ *    [0, 1, 2].count # => 3
+ *    [].count # => 0
  *
- *  If an argument is given, counts the number of elements which equal +obj+
- *  using <code>==</code>.
+ *  With argument +obj+, returns the count of elements <tt>==</tt> to +obj+:
  *
- *  If a block is given, counts the number of elements for which the block
- *  returns a true value.
+ *    [0, 1, 2, 0.0].count(0) # => 2
+ *    [0, 1, 2].count(3) # => 0
  *
- *     ary = [1, 2, 4, 2]
- *     ary.count                  #=> 4
- *     ary.count(2)               #=> 2
- *     ary.count { |x| x%2 == 0 } #=> 3
+ *  With no argument and a block given, calls the block with each element;
+ *  returns the count of elements for which the block returns a truthy value:
  *
+ *    [0, 1, 2, 3].count {|element| element > 1} # => 2
+ *
+ *  With argument +obj+ and a block given, issues a warning, ignores the block,
+ *  and returns the count of elements <tt>==</tt> to +obj+.
  */
 
 static VALUE
@@ -4269,104 +6493,152 @@ rb_ary_count(int argc, VALUE *argv, VALUE ary)
 {
     long i, n = 0;
 
-    if (argc == 0) {
-	VALUE v;
+    if (rb_check_arity(argc, 0, 1) == 0) {
+        VALUE v;
 
-	if (!rb_block_given_p())
-	    return LONG2NUM(RARRAY_LEN(ary));
+        if (!rb_block_given_p())
+            return LONG2NUM(RARRAY_LEN(ary));
 
-	for (i = 0; i < RARRAY_LEN(ary); i++) {
-	    v = RARRAY_AREF(ary, i);
-	    if (RTEST(rb_yield(v))) n++;
-	}
+        for (i = 0; i < RARRAY_LEN(ary); i++) {
+            v = RARRAY_AREF(ary, i);
+            if (RTEST(rb_yield(v))) n++;
+        }
     }
     else {
-	VALUE obj;
+        VALUE obj = argv[0];
 
-	rb_scan_args(argc, argv, "1", &obj);
-	if (rb_block_given_p()) {
-	    rb_warn("given block not used");
-	}
-	for (i = 0; i < RARRAY_LEN(ary); i++) {
-	    if (rb_equal(RARRAY_AREF(ary, i), obj)) n++;
-	}
+        if (rb_block_given_p()) {
+            rb_warn("given block not used");
+        }
+        for (i = 0; i < RARRAY_LEN(ary); i++) {
+            if (rb_equal(RARRAY_AREF(ary, i), obj)) n++;
+        }
     }
 
     return LONG2NUM(n);
 }
 
 static VALUE
-flatten(VALUE ary, int level, int *modified)
+flatten(VALUE ary, int level)
 {
-    long i = 0;
-    VALUE stack, result, tmp, elt;
-    st_table *memo;
+    long i;
+    VALUE stack, result, tmp = 0, elt, vmemo;
+    st_table *memo = 0;
     st_data_t id;
 
-    stack = ary_new(0, ARY_DEFAULT_SIZE);
+    for (i = 0; i < RARRAY_LEN(ary); i++) {
+        elt = RARRAY_AREF(ary, i);
+        tmp = rb_check_array_type(elt);
+        if (!NIL_P(tmp)) {
+            break;
+        }
+    }
+    if (i == RARRAY_LEN(ary)) {
+        return ary;
+    }
+
     result = ary_new(0, RARRAY_LEN(ary));
-    memo = st_init_numtable();
-    st_insert(memo, (st_data_t)ary, (st_data_t)Qtrue);
-    *modified = 0;
+    ary_memcpy(result, 0, i, RARRAY_CONST_PTR_TRANSIENT(ary));
+    ARY_SET_LEN(result, i);
+
+    stack = ary_new(0, ARY_DEFAULT_SIZE);
+    rb_ary_push(stack, ary);
+    rb_ary_push(stack, LONG2NUM(i + 1));
+
+    if (level < 0) {
+        vmemo = rb_hash_new();
+        RBASIC_CLEAR_CLASS(vmemo);
+        memo = st_init_numtable();
+        rb_hash_st_table_set(vmemo, memo);
+        st_insert(memo, (st_data_t)ary, (st_data_t)Qtrue);
+        st_insert(memo, (st_data_t)tmp, (st_data_t)Qtrue);
+    }
+
+    ary = tmp;
+    i = 0;
 
     while (1) {
-	while (i < RARRAY_LEN(ary)) {
-	    elt = RARRAY_AREF(ary, i++);
-	    tmp = rb_check_array_type(elt);
-	    if (RBASIC(result)->klass) {
-		rb_raise(rb_eRuntimeError, "flatten reentered");
-	    }
-	    if (NIL_P(tmp) || (level >= 0 && RARRAY_LEN(stack) / 2 >= level)) {
-		rb_ary_push(result, elt);
-	    }
-	    else {
-		*modified = 1;
-		id = (st_data_t)tmp;
-		if (st_lookup(memo, id, 0)) {
-		    st_free_table(memo);
-		    rb_raise(rb_eArgError, "tried to flatten recursive array");
-		}
-		st_insert(memo, id, (st_data_t)Qtrue);
-		rb_ary_push(stack, ary);
-		rb_ary_push(stack, LONG2NUM(i));
-		ary = tmp;
-		i = 0;
-	    }
-	}
-	if (RARRAY_LEN(stack) == 0) {
-	    break;
-	}
-	id = (st_data_t)ary;
-	st_delete(memo, &id, 0);
-	tmp = rb_ary_pop(stack);
-	i = NUM2LONG(tmp);
-	ary = rb_ary_pop(stack);
-    }
-
-    st_free_table(memo);
-
-    RBASIC_SET_CLASS(result, rb_class_of(ary));
+        while (i < RARRAY_LEN(ary)) {
+            elt = RARRAY_AREF(ary, i++);
+            if (level >= 0 && RARRAY_LEN(stack) / 2 >= level) {
+                rb_ary_push(result, elt);
+                continue;
+            }
+            tmp = rb_check_array_type(elt);
+            if (RBASIC(result)->klass) {
+                if (memo) {
+                    RB_GC_GUARD(vmemo);
+                    st_clear(memo);
+                }
+                rb_raise(rb_eRuntimeError, "flatten reentered");
+            }
+            if (NIL_P(tmp)) {
+                rb_ary_push(result, elt);
+            }
+            else {
+                if (memo) {
+                    id = (st_data_t)tmp;
+                    if (st_is_member(memo, id)) {
+                        st_clear(memo);
+                        rb_raise(rb_eArgError, "tried to flatten recursive array");
+                    }
+                    st_insert(memo, id, (st_data_t)Qtrue);
+                }
+                rb_ary_push(stack, ary);
+                rb_ary_push(stack, LONG2NUM(i));
+                ary = tmp;
+                i = 0;
+            }
+        }
+        if (RARRAY_LEN(stack) == 0) {
+            break;
+        }
+        if (memo) {
+            id = (st_data_t)ary;
+            st_delete(memo, &id, 0);
+        }
+        tmp = rb_ary_pop(stack);
+        i = NUM2LONG(tmp);
+        ary = rb_ary_pop(stack);
+    }
+
+    if (memo) {
+        st_clear(memo);
+    }
+
+    RBASIC_SET_CLASS(result, rb_cArray);
     return result;
 }
 
 /*
  *  call-seq:
- *     ary.flatten!        -> ary or nil
- *     ary.flatten!(level) -> ary or nil
+ *    array.flatten! -> self or nil
+ *    array.flatten!(level) -> self or nil
+ *
+ *  Replaces each nested \Array in +self+ with the elements from that \Array;
+ *  returns +self+ if any changes, +nil+ otherwise.
  *
- *  Flattens +self+ in place.
+ *  With non-negative \Integer argument +level+, flattens recursively through +level+ levels:
  *
- *  Returns +nil+ if no modifications were made (i.e., the array contains no
- *  subarrays.)
+ *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
+ *    a.flatten!(1) # => [0, 1, [2, 3], 4, 5]
+ *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
+ *    a.flatten!(2) # => [0, 1, 2, 3, 4, 5]
+ *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
+ *    a.flatten!(3) # => [0, 1, 2, 3, 4, 5]
+ *    [0, 1, 2].flatten!(1) # => nil
  *
- *  The optional +level+ argument determines the level of recursion to flatten.
+ *  With no argument, a +nil+ argument, or with negative argument +level+, flattens all levels:
+ *
+ *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
+ *    a.flatten! # => [0, 1, 2, 3, 4, 5]
+ *    [0, 1, 2].flatten! # => nil
+ *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
+ *    a.flatten!(-1) # => [0, 1, 2, 3, 4, 5]
+ *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
+ *    a.flatten!(-2) # => [0, 1, 2, 3, 4, 5]
+ *    [0, 1, 2].flatten!(-1) # => nil
  *
- *     a = [ 1, 2, [3, [4, 5] ] ]
- *     a.flatten!   #=> [1, 2, 3, 4, 5]
- *     a.flatten!   #=> nil
- *     a            #=> [1, 2, 3, 4, 5]
- *     a = [ 1, 2, [3, [4, 5] ] ]
- *     a.flatten!(1) #=> [1, 2, 3, [4, 5]]
  */
 
 static VALUE
@@ -4375,15 +6647,14 @@ rb_ary_flatten_bang(int argc, VALUE *argv, VALUE ary)
     int mod = 0, level = -1;
     VALUE result, lv;
 
-    rb_scan_args(argc, argv, "01", &lv);
+    lv = (rb_check_arity(argc, 0, 1) ? argv[0] : Qnil);
     rb_ary_modify_check(ary);
     if (!NIL_P(lv)) level = NUM2INT(lv);
     if (level == 0) return Qnil;
 
-    result = flatten(ary, level, &mod);
-    if (mod == 0) {
-	ary_discard(result);
-	return Qnil;
+    result = flatten(ary, level);
+    if (result == ary) {
+        return Qnil;
     }
     if (!(mod = ARY_EMBED_P(result))) rb_obj_freeze(result);
     rb_ary_replace(ary, result);
@@ -4394,239 +6665,212 @@ rb_ary_flatten_bang(int argc, VALUE *argv, VALUE ary)
 
 /*
  *  call-seq:
- *     ary.flatten -> new_ary
- *     ary.flatten(level) -> new_ary
- *
- *  Returns a new array that is a one-dimensional flattening of +self+
- *  (recursively).
- *
- *  That is, for every element that is an array, extract its elements into
- *  the new array.
- *
- *  The optional +level+ argument determines the level of recursion to
- *  flatten.
+ *    array.flatten -> new_array
+ *    array.flatten(level) -> new_array
+ *
+ *  Returns a new \Array that is a recursive flattening of +self+:
+ *  - Each non-Array element is unchanged.
+ *  - Each \Array is replaced by its individual elements.
+ *
+ *  With non-negative \Integer argument +level+, flattens recursively through +level+ levels:
+ *
+ *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
+ *    a.flatten(0) # => [0, [1, [2, 3], 4], 5]
+ *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
+ *    a.flatten(1) # => [0, 1, [2, 3], 4, 5]
+ *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
+ *    a.flatten(2) # => [0, 1, 2, 3, 4, 5]
+ *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
+ *    a.flatten(3) # => [0, 1, 2, 3, 4, 5]
+ *
+ *  With no argument, a +nil+ argument, or with negative argument +level+, flattens all levels:
+ *
+ *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
+ *    a.flatten # => [0, 1, 2, 3, 4, 5]
+ *    [0, 1, 2].flatten # => [0, 1, 2]
+ *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
+ *    a.flatten(-1) # => [0, 1, 2, 3, 4, 5]
+ *    a = [ 0, [ 1, [2, 3], 4 ], 5 ]
+ *    a.flatten(-2) # => [0, 1, 2, 3, 4, 5]
+ *    [0, 1, 2].flatten(-1) # => [0, 1, 2]
  *
- *     s = [ 1, 2, 3 ]           #=> [1, 2, 3]
- *     t = [ 4, 5, 6, [7, 8] ]   #=> [4, 5, 6, [7, 8]]
- *     a = [ s, t, 9, 10 ]       #=> [[1, 2, 3], [4, 5, 6, [7, 8]], 9, 10]
- *     a.flatten                 #=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
- *     a = [ 1, 2, [3, [4, 5] ] ]
- *     a.flatten(1)              #=> [1, 2, 3, [4, 5]]
  */
 
 static VALUE
 rb_ary_flatten(int argc, VALUE *argv, VALUE ary)
 {
-    int mod = 0, level = -1;
-    VALUE result, lv;
+    int level = -1;
+    VALUE result;
 
-    rb_scan_args(argc, argv, "01", &lv);
-    if (!NIL_P(lv)) level = NUM2INT(lv);
-    if (level == 0) return ary_make_shared_copy(ary);
+    if (rb_check_arity(argc, 0, 1) && !NIL_P(argv[0])) {
+        level = NUM2INT(argv[0]);
+        if (level == 0) return ary_make_shared_copy(ary);
+    }
 
-    result = flatten(ary, level, &mod);
-    OBJ_INFECT(result, ary);
+    result = flatten(ary, level);
+    if (result == ary) {
+        result = ary_make_shared_copy(ary);
+    }
 
     return result;
 }
 
-#define OPTHASH_GIVEN_P(opts) \
-    (argc > 0 && !NIL_P((opts) = rb_check_hash_type(argv[argc-1])) && (--argc, 1))
-static ID id_random;
-
 #define RAND_UPTO(max) (long)rb_random_ulong_limited((randgen), (max)-1)
 
-/*
- *  call-seq:
- *     ary.shuffle!              -> ary
- *     ary.shuffle!(random: rng) -> ary
- *
- *  Shuffles elements in +self+ in place.
- *
- *  The optional +rng+ argument will be used as the random number generator.
- */
-
 static VALUE
-rb_ary_shuffle_bang(int argc, VALUE *argv, VALUE ary)
+rb_ary_shuffle_bang(rb_execution_context_t *ec, VALUE ary, VALUE randgen)
 {
-    VALUE opts, randgen = rb_cRandom;
     long i, len;
 
-    if (OPTHASH_GIVEN_P(opts)) {
-	VALUE rnd;
-	ID keyword_ids[1];
-
-	keyword_ids[0] = id_random;
-	rb_get_kwargs(opts, keyword_ids, 0, 1, &rnd);
-	if (rnd != Qundef) {
-	    randgen = rnd;
-	}
-    }
-    rb_check_arity(argc, 0, 0);
     rb_ary_modify(ary);
     i = len = RARRAY_LEN(ary);
     RARRAY_PTR_USE(ary, ptr, {
-	while (i) {
-	    long j = RAND_UPTO(i);
-	    VALUE tmp;
-	    if (len != RARRAY_LEN(ary) || ptr != RARRAY_CONST_PTR(ary)) {
-		rb_raise(rb_eRuntimeError, "modified during shuffle");
-	    }
-	    tmp = ptr[--i];
-	    ptr[i] = ptr[j];
-	    ptr[j] = tmp;
-	}
+        while (i) {
+            long j = RAND_UPTO(i);
+            VALUE tmp;
+            if (len != RARRAY_LEN(ary) || ptr != RARRAY_CONST_PTR_TRANSIENT(ary)) {
+                rb_raise(rb_eRuntimeError, "modified during shuffle");
+            }
+            tmp = ptr[--i];
+            ptr[i] = ptr[j];
+            ptr[j] = tmp;
+        }
     }); /* WB: no new reference */
     return ary;
 }
 
-
-/*
- *  call-seq:
- *     ary.shuffle              -> new_ary
- *     ary.shuffle(random: rng) -> new_ary
- *
- *  Returns a new array with elements of +self+ shuffled.
- *
- *     a = [ 1, 2, 3 ]           #=> [1, 2, 3]
- *     a.shuffle                 #=> [2, 3, 1]
- *
- *  The optional +rng+ argument will be used as the random number generator.
- *
- *     a.shuffle(random: Random.new(1))  #=> [1, 3, 2]
- */
-
 static VALUE
-rb_ary_shuffle(int argc, VALUE *argv, VALUE ary)
+rb_ary_shuffle(rb_execution_context_t *ec, VALUE ary, VALUE randgen)
 {
     ary = rb_ary_dup(ary);
-    rb_ary_shuffle_bang(argc, argv, ary);
+    rb_ary_shuffle_bang(ec, ary, randgen);
     return ary;
 }
 
-
-/*
- *  call-seq:
- *     ary.sample                  -> obj
- *     ary.sample(random: rng)     -> obj
- *     ary.sample(n)               -> new_ary
- *     ary.sample(n, random: rng)  -> new_ary
- *
- *  Choose a random element or +n+ random elements from the array.
- *
- *  The elements are chosen by using random and unique indices into the array
- *  in order to ensure that an element doesn't repeat itself unless the array
- *  already contained duplicate elements.
- *
- *  If the array is empty the first form returns +nil+ and the second form
- *  returns an empty array.
- *
- *  The optional +rng+ argument will be used as the random number generator.
- *
- *     a = [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ]
- *     a.sample         #=> 7
- *     a.sample(4)      #=> [6, 4, 2, 5]
- */
-
-
 static VALUE
-rb_ary_sample(int argc, VALUE *argv, VALUE ary)
+ary_sample(rb_execution_context_t *ec, VALUE ary, VALUE randgen, VALUE nv, VALUE to_array)
 {
-    VALUE nv, result;
-    VALUE opts, randgen = rb_cRandom;
+    VALUE result;
     long n, len, i, j, k, idx[10];
     long rnds[numberof(idx)];
+    long memo_threshold;
 
-    if (OPTHASH_GIVEN_P(opts)) {
-	VALUE rnd;
-	ID keyword_ids[1];
-
-	keyword_ids[0] = id_random;
-	rb_get_kwargs(opts, keyword_ids, 0, 1, &rnd);
-	if (rnd != Qundef) {
-	    randgen = rnd;
-	}
-    }
     len = RARRAY_LEN(ary);
-    if (argc == 0) {
-	if (len < 2)
-	    i = 0;
-	else
-	    i = RAND_UPTO(len);
+    if (!to_array) {
+        if (len < 2)
+            i = 0;
+        else
+            i = RAND_UPTO(len);
 
-	return rb_ary_elt(ary, i);
+        return rb_ary_elt(ary, i);
     }
-    rb_scan_args(argc, argv, "1", &nv);
     n = NUM2LONG(nv);
     if (n < 0) rb_raise(rb_eArgError, "negative sample number");
     if (n > len) n = len;
     if (n <= numberof(idx)) {
-	for (i = 0; i < n; ++i) {
-	    rnds[i] = RAND_UPTO(len - i);
-	}
+        for (i = 0; i < n; ++i) {
+            rnds[i] = RAND_UPTO(len - i);
+        }
     }
     k = len;
     len = RARRAY_LEN(ary);
     if (len < k && n <= numberof(idx)) {
-	for (i = 0; i < n; ++i) {
-	    if (rnds[i] >= len) return rb_ary_new_capa(0);
-	}
+        for (i = 0; i < n; ++i) {
+            if (rnds[i] >= len) return rb_ary_new_capa(0);
+        }
     }
     if (n > len) n = len;
     switch (n) {
       case 0:
-	return rb_ary_new_capa(0);
+        return rb_ary_new_capa(0);
       case 1:
-	i = rnds[0];
-	return rb_ary_new_from_values(1, &RARRAY_AREF(ary, i));
+        i = rnds[0];
+        return rb_ary_new_from_args(1, RARRAY_AREF(ary, i));
       case 2:
-	i = rnds[0];
-	j = rnds[1];
-	if (j >= i) j++;
-	return rb_ary_new_from_args(2, RARRAY_AREF(ary, i), RARRAY_AREF(ary, j));
+        i = rnds[0];
+        j = rnds[1];
+        if (j >= i) j++;
+        return rb_ary_new_from_args(2, RARRAY_AREF(ary, i), RARRAY_AREF(ary, j));
       case 3:
-	i = rnds[0];
-	j = rnds[1];
-	k = rnds[2];
-	{
-	    long l = j, g = i;
-	    if (j >= i) l = i, g = ++j;
-	    if (k >= l && (++k >= g)) ++k;
-	}
-	return rb_ary_new_from_args(3, RARRAY_AREF(ary, i), RARRAY_AREF(ary, j), RARRAY_AREF(ary, k));
+        i = rnds[0];
+        j = rnds[1];
+        k = rnds[2];
+        {
+            long l = j, g = i;
+            if (j >= i) l = i, g = ++j;
+            if (k >= l && (++k >= g)) ++k;
+        }
+        return rb_ary_new_from_args(3, RARRAY_AREF(ary, i), RARRAY_AREF(ary, j), RARRAY_AREF(ary, k));
     }
+    memo_threshold =
+        len < 2560 ? len / 128 :
+        len < 5120 ? len / 64 :
+        len < 10240 ? len / 32 :
+        len / 16;
     if (n <= numberof(idx)) {
-	long sorted[numberof(idx)];
-	sorted[0] = idx[0] = rnds[0];
-	for (i=1; i<n; i++) {
-	    k = rnds[i];
-	    for (j = 0; j < i; ++j) {
-		if (k < sorted[j]) break;
-		++k;
-	    }
-	    memmove(&sorted[j+1], &sorted[j], sizeof(sorted[0])*(i-j));
-	    sorted[j] = idx[i] = k;
-	}
-	result = rb_ary_new_capa(n);
-	RARRAY_PTR_USE(result, ptr_result, {
-	    for (i=0; i<n; i++) {
-		ptr_result[i] = RARRAY_AREF(ary, idx[i]);
-	    }
-	});
+        long sorted[numberof(idx)];
+        sorted[0] = idx[0] = rnds[0];
+        for (i=1; i<n; i++) {
+            k = rnds[i];
+            for (j = 0; j < i; ++j) {
+                if (k < sorted[j]) break;
+                ++k;
+            }
+            memmove(&sorted[j+1], &sorted[j], sizeof(sorted[0])*(i-j));
+            sorted[j] = idx[i] = k;
+        }
+        result = rb_ary_new_capa(n);
+        RARRAY_PTR_USE_TRANSIENT(result, ptr_result, {
+            for (i=0; i<n; i++) {
+                ptr_result[i] = RARRAY_AREF(ary, idx[i]);
+            }
+        });
+    }
+    else if (n <= memo_threshold / 2) {
+        long max_idx = 0;
+#undef RUBY_UNTYPED_DATA_WARNING
+#define RUBY_UNTYPED_DATA_WARNING 0
+        VALUE vmemo = Data_Wrap_Struct(0, 0, st_free_table, 0);
+        st_table *memo = st_init_numtable_with_size(n);
+        DATA_PTR(vmemo) = memo;
+        result = rb_ary_new_capa(n);
+        RARRAY_PTR_USE(result, ptr_result, {
+            for (i=0; i<n; i++) {
+                long r = RAND_UPTO(len-i) + i;
+                ptr_result[i] = r;
+                if (r > max_idx) max_idx = r;
+            }
+            len = RARRAY_LEN(ary);
+            if (len <= max_idx) n = 0;
+            else if (n > len) n = len;
+            RARRAY_PTR_USE_TRANSIENT(ary, ptr_ary, {
+                for (i=0; i<n; i++) {
+                    long j2 = j = ptr_result[i];
+                    long i2 = i;
+                    st_data_t value;
+                    if (st_lookup(memo, (st_data_t)i, &value)) i2 = (long)value;
+                    if (st_lookup(memo, (st_data_t)j, &value)) j2 = (long)value;
+                    st_insert(memo, (st_data_t)j, (st_data_t)i2);
+                    ptr_result[i] = ptr_ary[j2];
+                }
+            });
+        });
+        DATA_PTR(vmemo) = 0;
+        st_free_table(memo);
     }
     else {
-	result = rb_ary_dup(ary);
-	RBASIC_CLEAR_CLASS(result);
-	RB_GC_GUARD(ary);
-	RARRAY_PTR_USE(result, ptr_result, {
-	    for (i=0; i<n; i++) {
-		j = RAND_UPTO(len-i) + i;
-		nv = ptr_result[j];
-		ptr_result[j] = ptr_result[i];
-		ptr_result[i] = nv;
-	    }
-	});
-	RBASIC_SET_CLASS_RAW(result, rb_cArray);
+        result = rb_ary_dup(ary);
+        RBASIC_CLEAR_CLASS(result);
+        RB_GC_GUARD(ary);
+        RARRAY_PTR_USE(result, ptr_result, {
+            for (i=0; i<n; i++) {
+                j = RAND_UPTO(len-i) + i;
+                nv = ptr_result[j];
+                ptr_result[j] = ptr_result[i];
+                ptr_result[i] = nv;
+            }
+        });
+        RBASIC_SET_CLASS_RAW(result, rb_cArray);
     }
     ARY_SET_LEN(result, n);
 
@@ -4634,55 +6878,73 @@ rb_ary_sample(int argc, VALUE *argv, VALUE ary)
 }
 
 static VALUE
+ary_sample0(rb_execution_context_t *ec, VALUE ary)
+{
+    return ary_sample(ec, ary, rb_cRandom, Qfalse, Qfalse);
+}
+
+static VALUE
 rb_ary_cycle_size(VALUE self, VALUE args, VALUE eobj)
 {
     long mul;
     VALUE n = Qnil;
     if (args && (RARRAY_LEN(args) > 0)) {
-	n = RARRAY_AREF(args, 0);
+        n = RARRAY_AREF(args, 0);
     }
     if (RARRAY_LEN(self) == 0) return INT2FIX(0);
-    if (n == Qnil) return DBL2NUM(INFINITY);
+    if (NIL_P(n)) return DBL2NUM(HUGE_VAL);
     mul = NUM2LONG(n);
     if (mul <= 0) return INT2FIX(0);
     n = LONG2FIX(mul);
-    return rb_funcallv(rb_ary_length(self), '*', 1, &n);
+    return rb_fix_mul_fix(rb_ary_length(self), n);
 }
 
 /*
  *  call-seq:
- *     ary.cycle(n=nil) { |obj| block }  -> nil
- *     ary.cycle(n=nil)                  -> Enumerator
+ *    array.cycle {|element| ... } -> nil
+ *    array.cycle(count) {|element| ... } -> nil
+ *    array.cycle -> new_enumerator
+ *    array.cycle(count) -> new_enumerator
  *
- *  Calls the given block for each element +n+ times or forever if +nil+ is
- *  given.
+ *  When called with positive \Integer argument +count+ and a block,
+ *  calls the block with each element, then does so again,
+ *  until it has done so +count+ times; returns +nil+:
  *
- *  Does nothing if a non-positive number is given or the array is empty.
+ *    output = []
+ *    [0, 1].cycle(2) {|element| output.push(element) } # => nil
+ *    output # => [0, 1, 0, 1]
  *
- *  Returns +nil+ if the loop has finished without getting interrupted.
+ *  If +count+ is zero or negative, does not call the block:
  *
- *  If no block is given, an Enumerator is returned instead.
+ *    [0, 1].cycle(0) {|element| fail 'Cannot happen' } # => nil
+ *    [0, 1].cycle(-1) {|element| fail 'Cannot happen' } # => nil
  *
- *     a = ["a", "b", "c"]
- *     a.cycle { |x| puts x }     # print, a, b, c, a, b, c,.. forever.
- *     a.cycle(2) { |x| puts x }  # print, a, b, c, a, b, c.
+ *  When a block is given, and argument is omitted or +nil+, cycles forever:
+ *
+ *    # Prints 0 and 1 forever.
+ *    [0, 1].cycle {|element| puts element }
+ *    [0, 1].cycle(nil) {|element| puts element }
+ *
+ *  When no block is given, returns a new \Enumerator:
+ *
+ *    [0, 1].cycle(2) # => #<Enumerator: [0, 1]:cycle(2)>
+ *    [0, 1].cycle # => # => #<Enumerator: [0, 1]:cycle>
+ *    [0, 1].cycle.first(5) # => [0, 1, 0, 1, 0]
  *
  */
-
 static VALUE
 rb_ary_cycle(int argc, VALUE *argv, VALUE ary)
 {
     long n, i;
-    VALUE nv = Qnil;
 
-    rb_scan_args(argc, argv, "01", &nv);
+    rb_check_arity(argc, 0, 1);
 
     RETURN_SIZED_ENUMERATOR(ary, argc, argv, rb_ary_cycle_size);
-    if (NIL_P(nv)) {
+    if (argc == 0 || NIL_P(argv[0])) {
         n = -1;
     }
     else {
-        n = NUM2LONG(nv);
+        n = NUM2LONG(argv[0]);
         if (n <= 0) return Qnil;
     }
 
@@ -4694,68 +6956,87 @@ rb_ary_cycle(int argc, VALUE *argv, VALUE ary)
     return Qnil;
 }
 
-#define tmpbuf(n, size) rb_str_tmp_new((n)*(size))
-#define tmpbuf_discard(s) (rb_str_resize((s), 0L), RBASIC_SET_CLASS_RAW(s, rb_cString))
-#define tmpary(n) rb_ary_tmp_new(n)
-#define tmpary_discard(a) (ary_discard(a), RBASIC_SET_CLASS_RAW(a, rb_cArray))
+/*
+ * Build a ruby array of the corresponding values and yield it to the
+ * associated block.
+ * Return the class of +values+ for reentry check.
+ */
+static int
+yield_indexed_values(const VALUE values, const long r, const long *const p)
+{
+    const VALUE result = rb_ary_new2(r);
+    long i;
+
+    for (i = 0; i < r; i++) ARY_SET(result, i, RARRAY_AREF(values, p[i]));
+    ARY_SET_LEN(result, r);
+    rb_yield(result);
+    return !RBASIC(values)->klass;
+}
 
 /*
- * Recursively compute permutations of +r+ elements of the set
- * <code>[0..n-1]</code>.
+ * Compute permutations of +r+ elements of the set <code>[0..n-1]</code>.
  *
- * When we have a complete permutation of array indexes, copy the values
- * at those indexes into a new array and yield that array.
+ * When we have a complete permutation of array indices, copy the values
+ * at those indices into a new array and yield that array.
  *
  * n: the size of the set
  * r: the number of elements in each permutation
  * p: the array (of size r) that we're filling in
- * index: what index we're filling in now
  * used: an array of booleans: whether a given index is already used
  * values: the Ruby array that holds the actual values to permute
  */
 static void
-permute0(long n, long r, long *p, long index, char *used, VALUE values)
+permute0(const long n, const long r, long *const p, char *const used, const VALUE values)
 {
-    long i,j;
-    for (i = 0; i < n; i++) {
-	if (used[i] == 0) {
-	    p[index] = i;
-	    if (index < r-1) {             /* if not done yet */
-		used[i] = 1;               /* mark index used */
-		permute0(n, r, p, index+1, /* recurse */
-			 used, values);
-		used[i] = 0;               /* index unused */
-	    }
-	    else {
-		/* We have a complete permutation of array indexes */
-		/* Build a ruby array of the corresponding values */
-		/* And yield it to the associated block */
-		VALUE result = rb_ary_new2(r);
-		VALUE *result_array = RARRAY_PTR(result);
-		const VALUE *values_array = RARRAY_PTR(values);
-
-		for (j = 0; j < r; j++) result_array[j] = values_array[p[j]];
-		ARY_SET_LEN(result, r);
-		rb_yield(result);
-		if (RBASIC(values)->klass) {
-		    rb_raise(rb_eRuntimeError, "permute reentered");
-		}
-	    }
-	}
+    long i = 0, index = 0;
+
+    for (;;) {
+        const char *const unused = memchr(&used[i], 0, n-i);
+        if (!unused) {
+            if (!index) break;
+            i = p[--index];                /* pop index */
+            used[i++] = 0;                 /* index unused */
+        }
+        else {
+            i = unused - used;
+            p[index] = i;
+            used[i] = 1;                   /* mark index used */
+            ++index;
+            if (index < r-1) {             /* if not done yet */
+                p[index] = i = 0;
+                continue;
+            }
+            for (i = 0; i < n; ++i) {
+                if (used[i]) continue;
+                p[index] = i;
+                if (!yield_indexed_values(values, r, p)) {
+                    rb_raise(rb_eRuntimeError, "permute reentered");
+                }
+            }
+            i = p[--index];                /* pop index */
+            used[i] = 0;                   /* index unused */
+            p[index] = ++i;
+        }
     }
 }
 
 /*
  * Returns the product of from, from-1, ..., from - how_many + 1.
- * http://en.wikipedia.org/wiki/Pochhammer_symbol
+ * https://en.wikipedia.org/wiki/Pochhammer_symbol
  */
 static VALUE
 descending_factorial(long from, long how_many)
 {
-    VALUE cnt = LONG2FIX(how_many >= 0);
-    while (how_many-- > 0) {
-	VALUE v = LONG2FIX(from--);
-	cnt = rb_funcallv(cnt, '*', 1, &v);
+    VALUE cnt;
+    if (how_many > 0) {
+        cnt = LONG2FIX(from);
+        while (--how_many > 0) {
+            long v = --from;
+            cnt = rb_int_mul(cnt, LONG2FIX(v));
+        }
+    }
+    else {
+        cnt = LONG2FIX(how_many == 0);
     }
     return cnt;
 }
@@ -4763,16 +7044,23 @@ descending_factorial(long from, long how_many)
 static VALUE
 binomial_coefficient(long comb, long size)
 {
-    VALUE r, v;
+    VALUE r;
+    long i;
     if (comb > size-comb) {
-	comb = size-comb;
+        comb = size-comb;
     }
     if (comb < 0) {
-	return LONG2FIX(0);
+        return LONG2FIX(0);
     }
-    r = descending_factorial(size, comb);
-    v = descending_factorial(comb, comb);
-    return rb_funcallv(r, id_div, 1, &v);
+    else if (comb == 0) {
+        return LONG2FIX(1);
+    }
+    r = LONG2FIX(size);
+    for (i = 1; i < comb; ++i) {
+        r = rb_int_mul(r, LONG2FIX(size - i));
+        r = rb_int_idiv(r, LONG2FIX(i + 1));
+    }
+    return r;
 }
 
 static VALUE
@@ -4786,72 +7074,143 @@ rb_ary_permutation_size(VALUE ary, VALUE args, VALUE eobj)
 
 /*
  *  call-seq:
- *     ary.permutation { |p| block }          -> ary
- *     ary.permutation                        -> Enumerator
- *     ary.permutation(n) { |p| block }       -> ary
- *     ary.permutation(n)                     -> Enumerator
+ *    array.permutation {|element| ... } -> self
+ *    array.permutation(n) {|element| ... } -> self
+ *    array.permutation -> new_enumerator
+ *    array.permutation(n) -> new_enumerator
+ *
+ *  When invoked with a block, yield all permutations of elements of +self+; returns +self+.
+ *  The order of permutations is indeterminate.
+ *
+ *  When a block and an in-range positive \Integer argument +n+ (<tt>0 < n <= self.size</tt>)
+ *  are given, calls the block with all +n+-tuple permutations of +self+.
+ *
+ *  Example:
+ *
+ *    a = [0, 1, 2]
+ *    a.permutation(2) {|permutation| p permutation }
+ *
+ *  Output:
+ *
+ *    [0, 1]
+ *    [0, 2]
+ *    [1, 0]
+ *    [1, 2]
+ *    [2, 0]
+ *    [2, 1]
+ *
+ *  Another example:
+ *
+ *    a = [0, 1, 2]
+ *    a.permutation(3) {|permutation| p permutation }
+ *
+ *  Output:
  *
- * When invoked with a block, yield all permutations of length +n+ of the
- * elements of the array, then return the array itself.
+ *    [0, 1, 2]
+ *    [0, 2, 1]
+ *    [1, 0, 2]
+ *    [1, 2, 0]
+ *    [2, 0, 1]
+ *    [2, 1, 0]
  *
- * If +n+ is not specified, yield all permutations of all elements.
+ *  When +n+ is zero, calls the block once with a new empty \Array:
  *
- * The implementation makes no guarantees about the order in which the
- * permutations are yielded.
+ *    a = [0, 1, 2]
+ *    a.permutation(0) {|permutation| p permutation }
  *
- * If no block is given, an Enumerator is returned instead.
+ *  Output:
  *
- * Examples:
+ *    []
+ *
+ *  When +n+ is out of range (negative or larger than <tt>self.size</tt>),
+ *  does not call the block:
+ *
+ *    a = [0, 1, 2]
+ *    a.permutation(-1) {|permutation| fail 'Cannot happen' }
+ *    a.permutation(4) {|permutation| fail 'Cannot happen' }
+ *
+ *  When a block given but no argument,
+ *  behaves the same as <tt>a.permutation(a.size)</tt>:
+ *
+ *    a = [0, 1, 2]
+ *    a.permutation {|permutation| p permutation }
+ *
+ *  Output:
+ *
+ *    [0, 1, 2]
+ *    [0, 2, 1]
+ *    [1, 0, 2]
+ *    [1, 2, 0]
+ *    [2, 0, 1]
+ *    [2, 1, 0]
+ *
+ *  Returns a new \Enumerator if no block given:
+ *
+ *    a = [0, 1, 2]
+ *    a.permutation # => #<Enumerator: [0, 1, 2]:permutation>
+ *    a.permutation(2) # => #<Enumerator: [0, 1, 2]:permutation(2)>
  *
- *   a = [1, 2, 3]
- *   a.permutation.to_a    #=> [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
- *   a.permutation(1).to_a #=> [[1],[2],[3]]
- *   a.permutation(2).to_a #=> [[1,2],[1,3],[2,1],[2,3],[3,1],[3,2]]
- *   a.permutation(3).to_a #=> [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
- *   a.permutation(0).to_a #=> [[]] # one permutation of length 0
- *   a.permutation(4).to_a #=> []   # no permutations of length 4
  */
 
 static VALUE
 rb_ary_permutation(int argc, VALUE *argv, VALUE ary)
 {
-    VALUE num;
     long r, n, i;
 
     n = RARRAY_LEN(ary);                  /* Array length */
     RETURN_SIZED_ENUMERATOR(ary, argc, argv, rb_ary_permutation_size);   /* Return enumerator if no block */
-    rb_scan_args(argc, argv, "01", &num);
-    r = NIL_P(num) ? n : NUM2LONG(num);   /* Permutation size from argument */
+    r = n;
+    if (rb_check_arity(argc, 0, 1) && !NIL_P(argv[0]))
+        r = NUM2LONG(argv[0]);            /* Permutation size from argument */
 
     if (r < 0 || n < r) {
-	/* no permutations: yield nothing */
+        /* no permutations: yield nothing */
     }
     else if (r == 0) { /* exactly one permutation: the zero-length array */
-	rb_yield(rb_ary_new2(0));
+        rb_yield(rb_ary_new2(0));
     }
     else if (r == 1) { /* this is a special, easy case */
-	for (i = 0; i < RARRAY_LEN(ary); i++) {
-	    rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
-	}
+        for (i = 0; i < RARRAY_LEN(ary); i++) {
+            rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
+        }
     }
     else {             /* this is the general case */
-	volatile VALUE t0 = tmpbuf(n,sizeof(long));
-	long *p = (long*)RSTRING_PTR(t0);
-	volatile VALUE t1 = tmpbuf(n,sizeof(char));
-	char *used = (char*)RSTRING_PTR(t1);
-	VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
-	RBASIC_CLEAR_CLASS(ary0);
+        volatile VALUE t0;
+        long *p = ALLOCV_N(long, t0, r+roomof(n, sizeof(long)));
+        char *used = (char*)(p + r);
+        VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
+        RBASIC_CLEAR_CLASS(ary0);
 
-	MEMZERO(used, char, n); /* initialize array */
+        MEMZERO(used, char, n); /* initialize array */
 
-	permute0(n, r, p, 0, used, ary0); /* compute and yield permutations */
-	tmpbuf_discard(t0);
-	tmpbuf_discard(t1);
-	RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
+        permute0(n, r, p, used, ary0); /* compute and yield permutations */
+        ALLOCV_END(t0);
+        RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
     }
     return ary;
 }
 
+static void
+combinate0(const long len, const long n, long *const stack, const VALUE values)
+{
+    long lev = 0;
+
+    MEMZERO(stack+1, long, n);
+    stack[0] = -1;
+    for (;;) {
+        for (lev++; lev < n; lev++) {
+            stack[lev+1] = stack[lev]+1;
+        }
+        if (!yield_indexed_values(values, n, stack+1)) {
+            rb_raise(rb_eRuntimeError, "combination reentered");
+        }
+        do {
+            if (lev == 0) return;
+            stack[lev--]++;
+        } while (stack[lev+1]+n == len+lev+1);
+    }
+}
+
 static VALUE
 rb_ary_combination_size(VALUE ary, VALUE args, VALUE eobj)
 {
@@ -4863,115 +7222,122 @@ rb_ary_combination_size(VALUE ary, VALUE args, VALUE eobj)
 
 /*
  *  call-seq:
- *     ary.combination(n) { |c| block }    -> ary
- *     ary.combination(n)                  -> Enumerator
+ *    array.combination(n) {|element| ... } -> self
+ *    array.combination(n) -> new_enumerator
+ *
+ *  Calls the block, if given, with combinations of elements of +self+;
+ *  returns +self+. The order of combinations is indeterminate.
+ *
+ *  When a block and an in-range positive \Integer argument +n+ (<tt>0 < n <= self.size</tt>)
+ *  are given, calls the block with all +n+-tuple combinations of +self+.
+ *
+ *  Example:
+ *
+ *    a = [0, 1, 2]
+ *    a.combination(2) {|combination| p combination }
+ *
+ *  Output:
+ *
+ *    [0, 1]
+ *    [0, 2]
+ *    [1, 2]
+ *
+ *  Another example:
+ *
+ *    a = [0, 1, 2]
+ *    a.combination(3) {|combination| p combination }
+ *
+ *  Output:
+ *
+ *    [0, 1, 2]
+ *
+ *  When +n+ is zero, calls the block once with a new empty \Array:
+ *
+ *    a = [0, 1, 2]
+ *    a1 = a.combination(0) {|combination| p combination }
  *
- * When invoked with a block, yields all combinations of length +n+ of elements
- * from the array and then returns the array itself.
+ *  Output:
  *
- * The implementation makes no guarantees about the order in which the
- * combinations are yielded.
+ *    []
  *
- * If no block is given, an Enumerator is returned instead.
+ *  When +n+ is out of range (negative or larger than <tt>self.size</tt>),
+ *  does not call the block:
  *
- * Examples:
+ *    a = [0, 1, 2]
+ *    a.combination(-1) {|combination| fail 'Cannot happen' }
+ *    a.combination(4) {|combination| fail 'Cannot happen' }
  *
- *     a = [1, 2, 3, 4]
- *     a.combination(1).to_a  #=> [[1],[2],[3],[4]]
- *     a.combination(2).to_a  #=> [[1,2],[1,3],[1,4],[2,3],[2,4],[3,4]]
- *     a.combination(3).to_a  #=> [[1,2,3],[1,2,4],[1,3,4],[2,3,4]]
- *     a.combination(4).to_a  #=> [[1,2,3,4]]
- *     a.combination(0).to_a  #=> [[]] # one combination of length 0
- *     a.combination(5).to_a  #=> []   # no combinations of length 5
+ *  Returns a new \Enumerator if no block given:
+ *
+ *    a = [0, 1, 2]
+ *    a.combination(2) # => #<Enumerator: [0, 1, 2]:combination(2)>
  *
  */
 
 static VALUE
 rb_ary_combination(VALUE ary, VALUE num)
 {
-    long n, i, len;
+    long i, n, len;
 
     n = NUM2LONG(num);
     RETURN_SIZED_ENUMERATOR(ary, 1, &num, rb_ary_combination_size);
     len = RARRAY_LEN(ary);
     if (n < 0 || len < n) {
-	/* yield nothing */
+        /* yield nothing */
     }
     else if (n == 0) {
-	rb_yield(rb_ary_new2(0));
+        rb_yield(rb_ary_new2(0));
     }
     else if (n == 1) {
-	for (i = 0; i < len; i++) {
-	    rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
-	}
+        for (i = 0; i < RARRAY_LEN(ary); i++) {
+            rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
+        }
     }
     else {
-	volatile VALUE t0 = tmpbuf(n+1, sizeof(long));
-	long *stack = (long*)RSTRING_PTR(t0);
-	volatile VALUE cc = tmpary(n);
-	VALUE *chosen = RARRAY_PTR(cc);
-	long lev = 0;
-
-	MEMZERO(stack, long, n);
-	stack[0] = -1;
-	for (;;) {
-	    chosen[lev] = RARRAY_AREF(ary, stack[lev+1]);
-	    for (lev++; lev < n; lev++) {
-		chosen[lev] = RARRAY_AREF(ary, stack[lev+1] = stack[lev]+1);
-	    }
-	    rb_yield(rb_ary_new4(n, chosen));
-	    if (RBASIC(t0)->klass) {
-		rb_raise(rb_eRuntimeError, "combination reentered");
-	    }
-	    do {
-		if (lev == 0) goto done;
-		stack[lev--]++;
-	    } while (stack[lev+1]+n == len+lev+1);
-	}
-    done:
-	tmpbuf_discard(t0);
-	tmpary_discard(cc);
+        VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
+        volatile VALUE t0;
+        long *stack = ALLOCV_N(long, t0, n+1);
+
+        RBASIC_CLEAR_CLASS(ary0);
+        combinate0(len, n, stack, ary0);
+        ALLOCV_END(t0);
+        RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
     }
     return ary;
 }
 
 /*
- * Recursively compute repeated permutations of +r+ elements of the set
+ * Compute repeated permutations of +r+ elements of the set
  * <code>[0..n-1]</code>.
  *
- * When we have a complete repeated permutation of array indexes, copy the
- * values at those indexes into a new array and yield that array.
+ * When we have a complete repeated permutation of array indices, copy the
+ * values at those indices into a new array and yield that array.
  *
  * n: the size of the set
  * r: the number of elements in each permutation
  * p: the array (of size r) that we're filling in
- * index: what index we're filling in now
  * values: the Ruby array that holds the actual values to permute
  */
 static void
-rpermute0(long n, long r, long *p, long index, VALUE values)
+rpermute0(const long n, const long r, long *const p, const VALUE values)
 {
-    long i, j;
-    for (i = 0; i < n; i++) {
-	p[index] = i;
-	if (index < r-1) {              /* if not done yet */
-	    rpermute0(n, r, p, index+1, values); /* recurse */
-	}
-	else {
-	    /* We have a complete permutation of array indexes */
-	    /* Build a ruby array of the corresponding values */
-	    /* And yield it to the associated block */
-	    VALUE result = rb_ary_new2(r);
-	    VALUE *result_array = RARRAY_PTR(result);
-	    const VALUE *values_array = RARRAY_PTR(values);
+    long i = 0, index = 0;
 
-	    for (j = 0; j < r; j++) result_array[j] = values_array[p[j]];
-	    ARY_SET_LEN(result, r);
-	    rb_yield(result);
-	    if (RBASIC(values)->klass) {
-		rb_raise(rb_eRuntimeError, "repeated permute reentered");
-	    }
-	}
+    p[index] = i;
+    for (;;) {
+        if (++index < r-1) {
+            p[index] = i = 0;
+            continue;
+        }
+        for (i = 0; i < n; ++i) {
+            p[index] = i;
+            if (!yield_indexed_values(values, r, p)) {
+                rb_raise(rb_eRuntimeError, "repeated permute reentered");
+            }
+        }
+        do {
+            if (index <= 0) return;
+        } while ((i = ++p[--index]) >= n);
     }
 }
 
@@ -4980,39 +7346,81 @@ rb_ary_repeated_permutation_size(VALUE ary, VALUE args, VALUE eobj)
 {
     long n = RARRAY_LEN(ary);
     long k = NUM2LONG(RARRAY_AREF(args, 0));
-    VALUE v;
 
     if (k < 0) {
-	return LONG2FIX(0);
+        return LONG2FIX(0);
     }
-
-    v = LONG2NUM(k);
-    return rb_funcallv(LONG2NUM(n), id_power, 1, &v);
+    if (n <= 0) {
+        return LONG2FIX(!k);
+    }
+    return rb_int_positive_pow(n, (unsigned long)k);
 }
 
 /*
  *  call-seq:
- *     ary.repeated_permutation(n) { |p| block } -> ary
- *     ary.repeated_permutation(n)               -> Enumerator
+ *    array.repeated_permutation(n) {|permutation| ... } -> self
+ *    array.repeated_permutation(n) -> new_enumerator
+ *
+ *  Calls the block with each repeated permutation of length +n+ of the elements of +self+;
+ *  each permutation is an \Array;
+ *  returns +self+. The order of the permutations is indeterminate.
+ *
+ *  When a block and a positive \Integer argument +n+ are given, calls the block with each
+ *  +n+-tuple repeated permutation of the elements of +self+.
+ *  The number of permutations is <tt>self.size**n</tt>.
+ *
+ *  +n+ = 1:
+ *
+ *    a = [0, 1, 2]
+ *    a.repeated_permutation(1) {|permutation| p permutation }
  *
- * When invoked with a block, yield all repeated permutations of length +n+ of
- * the elements of the array, then return the array itself.
+ *  Output:
  *
- * The implementation makes no guarantees about the order in which the repeated
- * permutations are yielded.
+ *    [0]
+ *    [1]
+ *    [2]
  *
- * If no block is given, an Enumerator is returned instead.
+ *  +n+ = 2:
  *
- * Examples:
+ *    a.repeated_permutation(2) {|permutation| p permutation }
+ *
+ *  Output:
+ *
+ *    [0, 0]
+ *    [0, 1]
+ *    [0, 2]
+ *    [1, 0]
+ *    [1, 1]
+ *    [1, 2]
+ *    [2, 0]
+ *    [2, 1]
+ *    [2, 2]
+ *
+ *  If +n+ is zero, calls the block once with an empty \Array.
+ *
+ *  If +n+ is negative, does not call the block:
+ *
+ *    a.repeated_permutation(-1) {|permutation| fail 'Cannot happen' }
+ *
+ *  Returns a new \Enumerator if no block given:
+ *
+ *    a = [0, 1, 2]
+ *    a.repeated_permutation(2) # => #<Enumerator: [0, 1, 2]:permutation(2)>
+ *
+ *  Using Enumerators, it's convenient to show the permutations and counts
+ *  for some values of +n+:
+ *
+ *    e = a.repeated_permutation(0)
+ *    e.size # => 1
+ *    e.to_a # => [[]]
+ *    e = a.repeated_permutation(1)
+ *    e.size # => 3
+ *    e.to_a # => [[0], [1], [2]]
+ *    e = a.repeated_permutation(2)
+ *    e.size # => 9
+ *    e.to_a # => [[0, 0], [0, 1], [0, 2], [1, 0], [1, 1], [1, 2], [2, 0], [2, 1], [2, 2]]
  *
- *     a = [1, 2]
- *     a.repeated_permutation(1).to_a  #=> [[1], [2]]
- *     a.repeated_permutation(2).to_a  #=> [[1,1],[1,2],[2,1],[2,2]]
- *     a.repeated_permutation(3).to_a  #=> [[1,1,1],[1,1,2],[1,2,1],[1,2,2],
- *                                     #    [2,1,1],[2,1,2],[2,2,1],[2,2,2]]
- *     a.repeated_permutation(0).to_a  #=> [[]] # one permutation of length 0
  */
-
 static VALUE
 rb_ary_repeated_permutation(VALUE ary, VALUE num)
 {
@@ -5023,50 +7431,49 @@ rb_ary_repeated_permutation(VALUE ary, VALUE num)
     r = NUM2LONG(num);                    /* Permutation size from argument */
 
     if (r < 0) {
-	/* no permutations: yield nothing */
+        /* no permutations: yield nothing */
     }
     else if (r == 0) { /* exactly one permutation: the zero-length array */
-	rb_yield(rb_ary_new2(0));
+        rb_yield(rb_ary_new2(0));
     }
     else if (r == 1) { /* this is a special, easy case */
-	for (i = 0; i < RARRAY_LEN(ary); i++) {
-	    rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
-	}
+        for (i = 0; i < RARRAY_LEN(ary); i++) {
+            rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
+        }
     }
     else {             /* this is the general case */
-	volatile VALUE t0 = tmpbuf(r, sizeof(long));
-	long *p = (long*)RSTRING_PTR(t0);
-	VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
-	RBASIC_CLEAR_CLASS(ary0);
+        volatile VALUE t0;
+        long *p = ALLOCV_N(long, t0, r);
+        VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
+        RBASIC_CLEAR_CLASS(ary0);
 
-	rpermute0(n, r, p, 0, ary0); /* compute and yield repeated permutations */
-	tmpbuf_discard(t0);
-	RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
+        rpermute0(n, r, p, ary0); /* compute and yield repeated permutations */
+        ALLOCV_END(t0);
+        RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
     }
     return ary;
 }
 
 static void
-rcombinate0(long n, long r, long *p, long index, long rest, VALUE values)
+rcombinate0(const long n, const long r, long *const p, const long rest, const VALUE values)
 {
-    long j;
-    if (rest > 0) {
-	for (; index < n; ++index) {
-	    p[r-rest] = index;
-	    rcombinate0(n, r, p, index, rest-1, values);
-	}
-    }
-    else {
-	VALUE result = rb_ary_new2(r);
-	VALUE *result_array = RARRAY_PTR(result);
-	const VALUE *values_array = RARRAY_PTR(values);
+    long i = 0, index = 0;
 
-	for (j = 0; j < r; ++j) result_array[j] = values_array[p[j]];
-	ARY_SET_LEN(result, r);
-	rb_yield(result);
-	if (RBASIC(values)->klass) {
-	    rb_raise(rb_eRuntimeError, "repeated combination reentered");
-	}
+    p[index] = i;
+    for (;;) {
+        if (++index < r-1) {
+            p[index] = i;
+            continue;
+        }
+        for (; i < n; ++i) {
+            p[index] = i;
+            if (!yield_indexed_values(values, r, p)) {
+                rb_raise(rb_eRuntimeError, "repeated combination reentered");
+            }
+        }
+        do {
+            if (index <= 0) return;
+        } while ((i = ++p[--index]) >= n);
     }
 }
 
@@ -5076,35 +7483,71 @@ rb_ary_repeated_combination_size(VALUE ary, VALUE args, VALUE eobj)
     long n = RARRAY_LEN(ary);
     long k = NUM2LONG(RARRAY_AREF(args, 0));
     if (k == 0) {
-	return LONG2FIX(1);
+        return LONG2FIX(1);
     }
     return binomial_coefficient(k, n + k - 1);
 }
 
 /*
  *  call-seq:
- *     ary.repeated_combination(n) { |c| block } -> ary
- *     ary.repeated_combination(n)               -> Enumerator
+ *    array.repeated_combination(n) {|combination| ... } -> self
+ *    array.repeated_combination(n) -> new_enumerator
+ *
+ *  Calls the block with each repeated combination of length +n+ of the elements of +self+;
+ *  each combination is an \Array;
+ *  returns +self+. The order of the combinations is indeterminate.
+ *
+ *  When a block and a positive \Integer argument +n+ are given, calls the block with each
+ *  +n+-tuple repeated combination of the elements of +self+.
+ *  The number of combinations is <tt>(n+1)(n+2)/2</tt>.
+ *
+ *  +n+ = 1:
+ *
+ *    a = [0, 1, 2]
+ *    a.repeated_combination(1) {|combination| p combination }
+ *
+ *  Output:
+ *
+ *    [0]
+ *    [1]
+ *    [2]
  *
- * When invoked with a block, yields all repeated combinations of length +n+ of
- * elements from the array and then returns the array itself.
+ *  +n+ = 2:
  *
- * The implementation makes no guarantees about the order in which the repeated
- * combinations are yielded.
+ *    a.repeated_combination(2) {|combination| p combination }
  *
- * If no block is given, an Enumerator is returned instead.
+ *  Output:
  *
- * Examples:
+ *    [0, 0]
+ *    [0, 1]
+ *    [0, 2]
+ *    [1, 1]
+ *    [1, 2]
+ *    [2, 2]
  *
- *   a = [1, 2, 3]
- *   a.repeated_combination(1).to_a  #=> [[1], [2], [3]]
- *   a.repeated_combination(2).to_a  #=> [[1,1],[1,2],[1,3],[2,2],[2,3],[3,3]]
- *   a.repeated_combination(3).to_a  #=> [[1,1,1],[1,1,2],[1,1,3],[1,2,2],[1,2,3],
- *                                   #    [1,3,3],[2,2,2],[2,2,3],[2,3,3],[3,3,3]]
- *   a.repeated_combination(4).to_a  #=> [[1,1,1,1],[1,1,1,2],[1,1,1,3],[1,1,2,2],[1,1,2,3],
- *                                   #    [1,1,3,3],[1,2,2,2],[1,2,2,3],[1,2,3,3],[1,3,3,3],
- *                                   #    [2,2,2,2],[2,2,2,3],[2,2,3,3],[2,3,3,3],[3,3,3,3]]
- *   a.repeated_combination(0).to_a  #=> [[]] # one combination of length 0
+ *  If +n+ is zero, calls the block once with an empty \Array.
+ *
+ *  If +n+ is negative, does not call the block:
+ *
+ *    a.repeated_combination(-1) {|combination| fail 'Cannot happen' }
+ *
+ *  Returns a new \Enumerator if no block given:
+ *
+ *    a = [0, 1, 2]
+ *    a.repeated_combination(2) # => #<Enumerator: [0, 1, 2]:combination(2)>
+ *
+ *  Using Enumerators, it's convenient to show the combinations and counts
+ *  for some values of +n+:
+ *
+ *    e = a.repeated_combination(0)
+ *    e.size # => 1
+ *    e.to_a # => [[]]
+ *    e = a.repeated_combination(1)
+ *    e.size # => 3
+ *    e.to_a # => [[0], [1], [2]]
+ *    e = a.repeated_combination(2)
+ *    e.size # => 6
+ *    e.to_a # => [[0, 0], [0, 1], [0, 2], [1, 1], [1, 2], [2, 2]]
  *
  */
 
@@ -5117,67 +7560,105 @@ rb_ary_repeated_combination(VALUE ary, VALUE num)
     RETURN_SIZED_ENUMERATOR(ary, 1, &num, rb_ary_repeated_combination_size);   /* Return enumerator if no block */
     len = RARRAY_LEN(ary);
     if (n < 0) {
-	/* yield nothing */
+        /* yield nothing */
     }
     else if (n == 0) {
-	rb_yield(rb_ary_new2(0));
+        rb_yield(rb_ary_new2(0));
     }
     else if (n == 1) {
-	for (i = 0; i < len; i++) {
-	    rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
-	}
+        for (i = 0; i < RARRAY_LEN(ary); i++) {
+            rb_yield(rb_ary_new3(1, RARRAY_AREF(ary, i)));
+        }
     }
     else if (len == 0) {
-	/* yield nothing */
+        /* yield nothing */
     }
     else {
-	volatile VALUE t0 = tmpbuf(n, sizeof(long));
-	long *p = (long*)RSTRING_PTR(t0);
-	VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
-	RBASIC_CLEAR_CLASS(ary0);
+        volatile VALUE t0;
+        long *p = ALLOCV_N(long, t0, n);
+        VALUE ary0 = ary_make_shared_copy(ary); /* private defensive copy of ary */
+        RBASIC_CLEAR_CLASS(ary0);
 
-	rcombinate0(len, n, p, 0, n, ary0); /* compute and yield repeated combinations */
-	tmpbuf_discard(t0);
-	RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
+        rcombinate0(len, n, p, n, ary0); /* compute and yield repeated combinations */
+        ALLOCV_END(t0);
+        RBASIC_SET_CLASS_RAW(ary0, rb_cArray);
     }
     return ary;
 }
 
 /*
  *  call-seq:
- *     ary.product(other_ary, ...)                -> new_ary
- *     ary.product(other_ary, ...) { |p| block }  -> ary
+ *    array.product(*other_arrays) -> new_array
+ *    array.product(*other_arrays) {|combination| ... } -> self
+ *
+ *  Computes and returns or yields all combinations of elements from all the Arrays,
+ *  including both +self+ and +other_arrays+:
  *
- *  Returns an array of all combinations of elements from all arrays.
+ *  - The number of combinations is the product of the sizes of all the arrays,
+ *    including both +self+ and +other_arrays+.
+ *  - The order of the returned combinations is indeterminate.
  *
- *  The length of the returned array is the product of the length of +self+ and
- *  the argument arrays.
+ *  When no block is given, returns the combinations as an \Array of Arrays:
  *
- *  If given a block, #product will yield all combinations and return +self+
- *  instead.
+ *    a = [0, 1, 2]
+ *    a1 = [3, 4]
+ *    a2 = [5, 6]
+ *    p = a.product(a1)
+ *    p.size # => 6 # a.size * a1.size
+ *    p # => [[0, 3], [0, 4], [1, 3], [1, 4], [2, 3], [2, 4]]
+ *    p = a.product(a1, a2)
+ *    p.size # => 12 # a.size * a1.size * a2.size
+ *    p # => [[0, 3, 5], [0, 3, 6], [0, 4, 5], [0, 4, 6], [1, 3, 5], [1, 3, 6], [1, 4, 5], [1, 4, 6], [2, 3, 5], [2, 3, 6], [2, 4, 5], [2, 4, 6]]
+ *
+ *  If any argument is an empty \Array, returns an empty \Array.
+ *
+ *  If no argument is given, returns an \Array of 1-element Arrays,
+ *  each containing an element of +self+:
+ *
+ *    a.product # => [[0], [1], [2]]
+ *
+ *  When a block is given, yields each combination as an \Array; returns +self+:
+ *
+ *    a.product(a1) {|combination| p combination }
+ *
+ *  Output:
+ *
+ *    [0, 3]
+ *    [0, 4]
+ *    [1, 3]
+ *    [1, 4]
+ *    [2, 3]
+ *    [2, 4]
+ *
+ *  If any argument is an empty \Array, does not call the block:
+ *
+ *    a.product(a1, a2, []) {|combination| fail 'Cannot happen' }
+ *
+ *  If no argument is given, yields each element of +self+ as a 1-element \Array:
+ *
+ *    a.product {|combination| p combination }
+ *
+ *  Output:
+ *
+ *    [0]
+ *    [1]
+ *    [2]
  *
- *     [1,2,3].product([4,5])     #=> [[1,4],[1,5],[2,4],[2,5],[3,4],[3,5]]
- *     [1,2].product([1,2])       #=> [[1,1],[1,2],[2,1],[2,2]]
- *     [1,2].product([3,4],[5,6]) #=> [[1,3,5],[1,3,6],[1,4,5],[1,4,6],
- *                                #     [2,3,5],[2,3,6],[2,4,5],[2,4,6]]
- *     [1,2].product()            #=> [[1],[2]]
- *     [1,2].product([])          #=> []
  */
 
 static VALUE
 rb_ary_product(int argc, VALUE *argv, VALUE ary)
 {
     int n = argc+1;    /* How many arrays we're operating on */
-    volatile VALUE t0 = tmpary(n);
-    volatile VALUE t1 = tmpbuf(n, sizeof(int));
+    volatile VALUE t0 = rb_ary_hidden_new(n);
+    volatile VALUE t1 = Qundef;
     VALUE *arrays = RARRAY_PTR(t0); /* The arrays we're computing the product of */
-    int *counters = (int*)RSTRING_PTR(t1); /* The current position in each one */
+    int *counters = ALLOCV_N(int, t1, n); /* The current position in each one */
     VALUE result = Qnil;      /* The array we'll be returning, when no block given */
     long i,j;
     long resultlen = 1;
 
     RBASIC_CLEAR_CLASS(t0);
-    RBASIC_CLEAR_CLASS(t1);
 
     /* initialize the arrays of arrays */
     ARY_SET_LEN(t0, n);
@@ -5190,81 +7671,84 @@ rb_ary_product(int argc, VALUE *argv, VALUE ary)
 
     /* Otherwise, allocate and fill in an array of results */
     if (rb_block_given_p()) {
-	/* Make defensive copies of arrays; exit if any is empty */
-	for (i = 0; i < n; i++) {
-	    if (RARRAY_LEN(arrays[i]) == 0) goto done;
-	    arrays[i] = ary_make_shared_copy(arrays[i]);
-	}
+        /* Make defensive copies of arrays; exit if any is empty */
+        for (i = 0; i < n; i++) {
+            if (RARRAY_LEN(arrays[i]) == 0) goto done;
+            arrays[i] = ary_make_shared_copy(arrays[i]);
+        }
     }
     else {
-	/* Compute the length of the result array; return [] if any is empty */
-	for (i = 0; i < n; i++) {
-	    long k = RARRAY_LEN(arrays[i]);
-	    if (k == 0) {
-		result = rb_ary_new2(0);
-		goto done;
-	    }
+        /* Compute the length of the result array; return [] if any is empty */
+        for (i = 0; i < n; i++) {
+            long k = RARRAY_LEN(arrays[i]);
+            if (k == 0) {
+                result = rb_ary_new2(0);
+                goto done;
+            }
             if (MUL_OVERFLOW_LONG_P(resultlen, k))
-		rb_raise(rb_eRangeError, "too big to product");
-	    resultlen *= k;
-	}
-	result = rb_ary_new2(resultlen);
+                rb_raise(rb_eRangeError, "too big to product");
+            resultlen *= k;
+        }
+        result = rb_ary_new2(resultlen);
     }
     for (;;) {
-	int m;
-	/* fill in one subarray */
-	VALUE subarray = rb_ary_new2(n);
-	for (j = 0; j < n; j++) {
-	    rb_ary_push(subarray, rb_ary_entry(arrays[j], counters[j]));
-	}
-
-	/* put it on the result array */
-	if (NIL_P(result)) {
-	    FL_SET(t0, FL_USER5);
-	    rb_yield(subarray);
-	    if (! FL_TEST(t0, FL_USER5)) {
-		rb_raise(rb_eRuntimeError, "product reentered");
-	    }
-	    else {
-		FL_UNSET(t0, FL_USER5);
-	    }
-	}
-	else {
-	    rb_ary_push(result, subarray);
-	}
-
-	/*
-	 * Increment the last counter.  If it overflows, reset to 0
-	 * and increment the one before it.
-	 */
-	m = n-1;
-	counters[m]++;
-	while (counters[m] == RARRAY_LEN(arrays[m])) {
-	    counters[m] = 0;
-	    /* If the first counter overflows, we are done */
-	    if (--m < 0) goto done;
-	    counters[m]++;
-	}
+        int m;
+        /* fill in one subarray */
+        VALUE subarray = rb_ary_new2(n);
+        for (j = 0; j < n; j++) {
+            rb_ary_push(subarray, rb_ary_entry(arrays[j], counters[j]));
+        }
+
+        /* put it on the result array */
+        if (NIL_P(result)) {
+            FL_SET(t0, RARRAY_SHARED_ROOT_FLAG);
+            rb_yield(subarray);
+            if (!FL_TEST(t0, RARRAY_SHARED_ROOT_FLAG)) {
+                rb_raise(rb_eRuntimeError, "product reentered");
+            }
+            else {
+                FL_UNSET(t0, RARRAY_SHARED_ROOT_FLAG);
+            }
+        }
+        else {
+            rb_ary_push(result, subarray);
+        }
+
+        /*
+         * Increment the last counter.  If it overflows, reset to 0
+         * and increment the one before it.
+         */
+        m = n-1;
+        counters[m]++;
+        while (counters[m] == RARRAY_LEN(arrays[m])) {
+            counters[m] = 0;
+            /* If the first counter overflows, we are done */
+            if (--m < 0) goto done;
+            counters[m]++;
+        }
     }
+
 done:
-    tmpary_discard(t0);
-    tmpbuf_discard(t1);
+    ALLOCV_END(t1);
 
     return NIL_P(result) ? ary : result;
 }
 
 /*
  *  call-seq:
- *     ary.take(n)               -> new_ary
+ *    array.take(n) -> new_array
  *
- *  Returns first +n+ elements from the array.
+ *  Returns a new \Array containing the first +n+ element of +self+,
+ *  where +n+ is a non-negative \Integer;
+ *  does not modify +self+.
  *
- *  If a negative number is given, raises an ArgumentError.
+ *  Examples:
  *
- *  See also Array#drop
- *
- *     a = [1, 2, 3, 4, 5, 0]
- *     a.take(3)             #=> [1, 2, 3]
+ *    a = [0, 1, 2, 3, 4, 5]
+ *    a.take(1) # => [0]
+ *    a.take(2) # => [0, 1]
+ *    a.take(50) # => [0, 1, 2, 3, 4, 5]
+ *    a # => [0, 1, 2, 3, 4, 5]
  *
  */
 
@@ -5273,25 +7757,31 @@ rb_ary_take(VALUE obj, VALUE n)
 {
     long len = NUM2LONG(n);
     if (len < 0) {
-	rb_raise(rb_eArgError, "attempt to take negative size");
+        rb_raise(rb_eArgError, "attempt to take negative size");
     }
     return rb_ary_subseq(obj, 0, len);
 }
 
 /*
  *  call-seq:
- *     ary.take_while { |arr| block }  -> new_ary
- *     ary.take_while                  -> Enumerator
+ *    array.take_while {|element| ... } -> new_array
+ *    array.take_while -> new_enumerator
+ *
+ *  Returns a new \Array containing zero or more leading elements of +self+;
+ *  does not modify +self+.
  *
- *  Passes elements to the block until the block returns +nil+ or +false+, then
- *  stops iterating and returns an array of all prior elements.
+ *  With a block given, calls the block with each successive element of +self+;
+ *  stops if the block returns +false+ or +nil+;
+ *  returns a new \Array containing those elements for which the block returned a truthy value:
  *
- *  If no block is given, an Enumerator is returned instead.
+ *    a = [0, 1, 2, 3, 4, 5]
+ *    a.take_while {|element| element < 3 } # => [0, 1, 2]
+ *    a.take_while {|element| true } # => [0, 1, 2, 3, 4, 5]
+ *    a # => [0, 1, 2, 3, 4, 5]
  *
- *  See also Array#drop_while
+ *  With no block given, returns a new \Enumerator:
  *
- *     a = [1, 2, 3, 4, 5, 0]
- *     a.take_while { |i| i < 3 }  #=> [1, 2]
+ *    [0, 1].take_while # => #<Enumerator: [0, 1]:take_while>
  *
  */
 
@@ -5302,24 +7792,25 @@ rb_ary_take_while(VALUE ary)
 
     RETURN_ENUMERATOR(ary, 0, 0);
     for (i = 0; i < RARRAY_LEN(ary); i++) {
-	if (!RTEST(rb_yield(RARRAY_AREF(ary, i)))) break;
+        if (!RTEST(rb_yield(RARRAY_AREF(ary, i)))) break;
     }
     return rb_ary_take(ary, LONG2FIX(i));
 }
 
 /*
  *  call-seq:
- *     ary.drop(n)               -> new_ary
+ *    array.drop(n) -> new_array
  *
- *  Drops first +n+ elements from +ary+ and returns the rest of the elements in
- *  an array.
+ *  Returns a new \Array containing all but the first +n+ element of +self+,
+ *  where +n+ is a non-negative \Integer;
+ *  does not modify +self+.
  *
- *  If a negative number is given, raises an ArgumentError.
+ *  Examples:
  *
- *  See also Array#take
- *
- *     a = [1, 2, 3, 4, 5, 0]
- *     a.drop(3)             #=> [4, 5, 0]
+ *    a = [0, 1, 2, 3, 4, 5]
+ *    a.drop(0) # => [0, 1, 2, 3, 4, 5]
+ *    a.drop(1) # => [1, 2, 3, 4, 5]
+ *    a.drop(2) # => [2, 3, 4, 5]
  *
  */
 
@@ -5329,29 +7820,32 @@ rb_ary_drop(VALUE ary, VALUE n)
     VALUE result;
     long pos = NUM2LONG(n);
     if (pos < 0) {
-	rb_raise(rb_eArgError, "attempt to drop negative size");
+        rb_raise(rb_eArgError, "attempt to drop negative size");
     }
 
     result = rb_ary_subseq(ary, pos, RARRAY_LEN(ary));
-    if (result == Qnil) result = rb_ary_new();
+    if (NIL_P(result)) result = rb_ary_new();
     return result;
 }
 
 /*
  *  call-seq:
- *     ary.drop_while { |arr| block }   -> new_ary
- *     ary.drop_while                  -> Enumerator
+ *    array.drop_while {|element| ... } -> new_array
+ *    array.drop_while -> new_enumerator
+
+ *  Returns a new \Array containing zero or more trailing elements of +self+;
+ *  does not modify +self+.
  *
- *  Drops elements up to, but not including, the first element for which the
- *  block returns +nil+ or +false+ and returns an array containing the
- *  remaining elements.
+ *  With a block given, calls the block with each successive element of +self+;
+ *  stops if the block returns +false+ or +nil+;
+ *  returns a new \Array _omitting_ those elements for which the block returned a truthy value:
  *
- *  If no block is given, an Enumerator is returned instead.
+ *    a = [0, 1, 2, 3, 4, 5]
+ *    a.drop_while {|element| element < 3 } # => [3, 4, 5]
  *
- *  See also Array#take_while
+ *  With no block given, returns a new \Enumerator:
  *
- *     a = [1, 2, 3, 4, 5, 0]
- *     a.drop_while {|i| i < 3 }   #=> [3, 4, 5, 0]
+ *    [0, 1].drop_while # => # => #<Enumerator: [0, 1]:drop_while>
  *
  */
 
@@ -5362,60 +7856,588 @@ rb_ary_drop_while(VALUE ary)
 
     RETURN_ENUMERATOR(ary, 0, 0);
     for (i = 0; i < RARRAY_LEN(ary); i++) {
-	if (!RTEST(rb_yield(RARRAY_AREF(ary, i)))) break;
+        if (!RTEST(rb_yield(RARRAY_AREF(ary, i)))) break;
     }
     return rb_ary_drop(ary, LONG2FIX(i));
 }
 
 /*
- *  Arrays are ordered, integer-indexed collections of any object.
+ *  call-seq:
+ *    array.any? -> true or false
+ *    array.any? {|element| ... } -> true or false
+ *    array.any?(obj) -> true or false
+ *
+ *  Returns +true+ if any element of +self+ meets a given criterion.
+ *
+ *  With no block given and no argument, returns +true+ if +self+ has any truthy element,
+ *  +false+ otherwise:
+ *
+ *    [nil, 0, false].any? # => true
+ *    [nil, false].any? # => false
+ *    [].any? # => false
+ *
+ *  With a block given and no argument, calls the block with each element in +self+;
+ *  returns +true+ if the block returns any truthy value, +false+ otherwise:
+ *
+ *    [0, 1, 2].any? {|element| element > 1 } # => true
+ *    [0, 1, 2].any? {|element| element > 2 } # => false
+ *
+ *  If argument +obj+ is given, returns +true+ if +obj+.<tt>===</tt> any element,
+ *  +false+ otherwise:
+ *
+ *    ['food', 'drink'].any?(/foo/) # => true
+ *    ['food', 'drink'].any?(/bar/) # => false
+ *    [].any?(/foo/) # => false
+ *    [0, 1, 2].any?(1) # => true
+ *    [0, 1, 2].any?(3) # => false
+ *
+ *  Related: Enumerable#any?
+ */
+
+static VALUE
+rb_ary_any_p(int argc, VALUE *argv, VALUE ary)
+{
+    long i, len = RARRAY_LEN(ary);
+
+    rb_check_arity(argc, 0, 1);
+    if (!len) return Qfalse;
+    if (argc) {
+        if (rb_block_given_p()) {
+            rb_warn("given block not used");
+        }
+        for (i = 0; i < RARRAY_LEN(ary); ++i) {
+            if (RTEST(rb_funcall(argv[0], idEqq, 1, RARRAY_AREF(ary, i)))) return Qtrue;
+        }
+    }
+    else if (!rb_block_given_p()) {
+        for (i = 0; i < len; ++i) {
+            if (RTEST(RARRAY_AREF(ary, i))) return Qtrue;
+        }
+    }
+    else {
+        for (i = 0; i < RARRAY_LEN(ary); ++i) {
+            if (RTEST(rb_yield(RARRAY_AREF(ary, i)))) return Qtrue;
+        }
+    }
+    return Qfalse;
+}
+
+/*
+ *  call-seq:
+ *    array.all? -> true or false
+ *    array.all? {|element| ... } -> true or false
+ *    array.all?(obj) -> true or false
+ *
+ *  Returns +true+ if all elements of +self+ meet a given criterion.
+ *
+ *  With no block given and no argument, returns +true+ if +self+ contains only truthy elements,
+ *  +false+ otherwise:
+ *
+ *    [0, 1, :foo].all? # => true
+ *    [0, nil, 2].all? # => false
+ *    [].all? # => true
+ *
+ *  With a block given and no argument, calls the block with each element in +self+;
+ *  returns +true+ if the block returns only truthy values, +false+ otherwise:
+ *
+ *    [0, 1, 2].all? { |element| element < 3 } # => true
+ *    [0, 1, 2].all? { |element| element < 2 } # => false
+ *
+ *  If argument +obj+ is given, returns +true+ if <tt>obj.===</tt> every element, +false+ otherwise:
+ *
+ *    ['food', 'fool', 'foot'].all?(/foo/) # => true
+ *    ['food', 'drink'].all?(/bar/) # => false
+ *    [].all?(/foo/) # => true
+ *    [0, 0, 0].all?(0) # => true
+ *    [0, 1, 2].all?(1) # => false
+ *
+ *  Related: Enumerable#all?
+ */
+
+static VALUE
+rb_ary_all_p(int argc, VALUE *argv, VALUE ary)
+{
+    long i, len = RARRAY_LEN(ary);
+
+    rb_check_arity(argc, 0, 1);
+    if (!len) return Qtrue;
+    if (argc) {
+        if (rb_block_given_p()) {
+            rb_warn("given block not used");
+        }
+        for (i = 0; i < RARRAY_LEN(ary); ++i) {
+            if (!RTEST(rb_funcall(argv[0], idEqq, 1, RARRAY_AREF(ary, i)))) return Qfalse;
+        }
+    }
+    else if (!rb_block_given_p()) {
+        for (i = 0; i < len; ++i) {
+            if (!RTEST(RARRAY_AREF(ary, i))) return Qfalse;
+        }
+    }
+    else {
+        for (i = 0; i < RARRAY_LEN(ary); ++i) {
+            if (!RTEST(rb_yield(RARRAY_AREF(ary, i)))) return Qfalse;
+        }
+    }
+    return Qtrue;
+}
+
+/*
+ *  call-seq:
+ *    array.none? -> true or false
+ *    array.none? {|element| ... } -> true or false
+ *    array.none?(obj) -> true or false
+ *
+ *  Returns +true+ if no element of +self+ meet a given criterion.
+ *
+ *  With no block given and no argument, returns +true+ if +self+ has no truthy elements,
+ *  +false+ otherwise:
+ *
+ *    [nil, false].none? # => true
+ *    [nil, 0, false].none? # => false
+ *    [].none? # => true
+ *
+ *  With a block given and no argument, calls the block with each element in +self+;
+ *  returns +true+ if the block returns no truthy value, +false+ otherwise:
+ *
+ *    [0, 1, 2].none? {|element| element > 3 } # => true
+ *    [0, 1, 2].none? {|element| element > 1 } # => false
+ *
+ *  If argument +obj+ is given, returns +true+ if <tt>obj.===</tt> no element, +false+ otherwise:
+ *
+ *    ['food', 'drink'].none?(/bar/) # => true
+ *    ['food', 'drink'].none?(/foo/) # => false
+ *    [].none?(/foo/) # => true
+ *    [0, 1, 2].none?(3) # => true
+ *    [0, 1, 2].none?(1) # => false
+ *
+ *  Related: Enumerable#none?
+ */
+
+static VALUE
+rb_ary_none_p(int argc, VALUE *argv, VALUE ary)
+{
+    long i, len = RARRAY_LEN(ary);
+
+    rb_check_arity(argc, 0, 1);
+    if (!len) return Qtrue;
+    if (argc) {
+        if (rb_block_given_p()) {
+            rb_warn("given block not used");
+        }
+        for (i = 0; i < RARRAY_LEN(ary); ++i) {
+            if (RTEST(rb_funcall(argv[0], idEqq, 1, RARRAY_AREF(ary, i)))) return Qfalse;
+        }
+    }
+    else if (!rb_block_given_p()) {
+        for (i = 0; i < len; ++i) {
+            if (RTEST(RARRAY_AREF(ary, i))) return Qfalse;
+        }
+    }
+    else {
+        for (i = 0; i < RARRAY_LEN(ary); ++i) {
+            if (RTEST(rb_yield(RARRAY_AREF(ary, i)))) return Qfalse;
+        }
+    }
+    return Qtrue;
+}
+
+/*
+ *  call-seq:
+ *    array.one? -> true or false
+ *    array.one? {|element| ... } -> true or false
+ *    array.one?(obj) -> true or false
+ *
+ *  Returns +true+ if exactly one element of +self+ meets a given criterion.
+ *
+ *  With no block given and no argument, returns +true+ if +self+ has exactly one truthy element,
+ *  +false+ otherwise:
+ *
+ *    [nil, 0].one? # => true
+ *    [0, 0].one? # => false
+ *    [nil, nil].one? # => false
+ *    [].one? # => false
+ *
+ *  With a block given and no argument, calls the block with each element in +self+;
+ *  returns +true+ if the block a truthy value for exactly one element, +false+ otherwise:
+ *
+ *    [0, 1, 2].one? {|element| element > 0 } # => false
+ *    [0, 1, 2].one? {|element| element > 1 } # => true
+ *    [0, 1, 2].one? {|element| element > 2 } # => false
+ *
+ *  If argument +obj+ is given, returns +true+ if <tt>obj.===</tt> exactly one element,
+ *  +false+ otherwise:
+ *
+ *    [0, 1, 2].one?(0) # => true
+ *    [0, 0, 1].one?(0) # => false
+ *    [1, 1, 2].one?(0) # => false
+ *    ['food', 'drink'].one?(/bar/) # => false
+ *    ['food', 'drink'].one?(/foo/) # => true
+ *    [].one?(/foo/) # => false
+ *
+ *  Related: Enumerable#one?
+ */
+
+static VALUE
+rb_ary_one_p(int argc, VALUE *argv, VALUE ary)
+{
+    long i, len = RARRAY_LEN(ary);
+    VALUE result = Qfalse;
+
+    rb_check_arity(argc, 0, 1);
+    if (!len) return Qfalse;
+    if (argc) {
+        if (rb_block_given_p()) {
+            rb_warn("given block not used");
+        }
+        for (i = 0; i < RARRAY_LEN(ary); ++i) {
+            if (RTEST(rb_funcall(argv[0], idEqq, 1, RARRAY_AREF(ary, i)))) {
+                if (result) return Qfalse;
+                result = Qtrue;
+            }
+        }
+    }
+    else if (!rb_block_given_p()) {
+        for (i = 0; i < len; ++i) {
+            if (RTEST(RARRAY_AREF(ary, i))) {
+                if (result) return Qfalse;
+                result = Qtrue;
+            }
+        }
+    }
+    else {
+        for (i = 0; i < RARRAY_LEN(ary); ++i) {
+            if (RTEST(rb_yield(RARRAY_AREF(ary, i)))) {
+                if (result) return Qfalse;
+                result = Qtrue;
+            }
+        }
+    }
+    return result;
+}
+
+/*
+ *  call-seq:
+ *    array.dig(index, *identifiers) -> object
+ *
+ *  Finds and returns the object in nested objects
+ *  that is specified by +index+ and +identifiers+.
+ *  The nested objects may be instances of various classes.
+ *  See {Dig Methods}[rdoc-ref:dig_methods.rdoc].
+ *
+ *  Examples:
+ *
+ *    a = [:foo, [:bar, :baz, [:bat, :bam]]]
+ *    a.dig(1) # => [:bar, :baz, [:bat, :bam]]
+ *    a.dig(1, 2) # => [:bat, :bam]
+ *    a.dig(1, 2, 0) # => :bat
+ *    a.dig(1, 2, 3) # => nil
+ *
+ */
+
+static VALUE
+rb_ary_dig(int argc, VALUE *argv, VALUE self)
+{
+    rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);
+    self = rb_ary_at(self, *argv);
+    if (!--argc) return self;
+    ++argv;
+    return rb_obj_dig(argc, argv, self, Qnil);
+}
+
+static inline VALUE
+finish_exact_sum(long n, VALUE r, VALUE v, int z)
+{
+    if (n != 0)
+        v = rb_fix_plus(LONG2FIX(n), v);
+    if (!UNDEF_P(r)) {
+        v = rb_rational_plus(r, v);
+    }
+    else if (!n && z) {
+        v = rb_fix_plus(LONG2FIX(0), v);
+    }
+    return v;
+}
+
+/*
+ * call-seq:
+ *   array.sum(init = 0) -> object
+ *   array.sum(init = 0) {|element| ... } -> object
+ *
+ *  When no block is given, returns the object equivalent to:
+ *
+ *    sum = init
+ *    array.each {|element| sum += element }
+ *    sum
+ *
+ *  For example, <tt>[e1, e2, e3].sum</tt> returns <tt>init + e1 + e2 + e3</tt>.
+ *
+ *  Examples:
+ *
+ *    a = [0, 1, 2, 3]
+ *    a.sum # => 6
+ *    a.sum(100) # => 106
+ *
+ *  The elements need not be numeric, but must be <tt>+</tt>-compatible
+ *  with each other and with +init+:
+ *
+ *    a = ['abc', 'def', 'ghi']
+ *    a.sum('jkl') # => "jklabcdefghi"
+ *
+ *  When a block is given, it is called with each element
+ *  and the block's return value (instead of the element itself) is used as the addend:
+ *
+ *    a = ['zero', 1, :two]
+ *    s = a.sum('Coerced and concatenated: ') {|element| element.to_s }
+ *    s # => "Coerced and concatenated: zero1two"
+ *
+ *  Notes:
+ *
+ *  - Array#join and Array#flatten may be faster than Array#sum
+ *    for an \Array of Strings or an \Array of Arrays.
+ *  - Array#sum method may not respect method redefinition of "+" methods such as Integer#+.
+ *
+ */
+
+static VALUE
+rb_ary_sum(int argc, VALUE *argv, VALUE ary)
+{
+    VALUE e, v, r;
+    long i, n;
+    int block_given;
+
+    v = (rb_check_arity(argc, 0, 1) ? argv[0] : LONG2FIX(0));
+
+    block_given = rb_block_given_p();
+
+    if (RARRAY_LEN(ary) == 0)
+        return v;
+
+    n = 0;
+    r = Qundef;
+    for (i = 0; i < RARRAY_LEN(ary); i++) {
+        e = RARRAY_AREF(ary, i);
+        if (block_given)
+            e = rb_yield(e);
+        if (FIXNUM_P(e)) {
+            n += FIX2LONG(e); /* should not overflow long type */
+            if (!FIXABLE(n)) {
+                v = rb_big_plus(LONG2NUM(n), v);
+                n = 0;
+            }
+        }
+        else if (RB_BIGNUM_TYPE_P(e))
+            v = rb_big_plus(e, v);
+        else if (RB_TYPE_P(e, T_RATIONAL)) {
+            if (UNDEF_P(r))
+                r = e;
+            else
+                r = rb_rational_plus(r, e);
+        }
+        else
+            goto not_exact;
+    }
+    v = finish_exact_sum(n, r, v, argc!=0);
+    return v;
+
+  not_exact:
+    v = finish_exact_sum(n, r, v, i!=0);
+
+    if (RB_FLOAT_TYPE_P(e)) {
+        /*
+         * Kahan-Babuska balancing compensated summation algorithm
+         * See https://link.springer.com/article/10.1007/s00607-005-0139-x
+         */
+        double f, c;
+        double x, t;
+
+        f = NUM2DBL(v);
+        c = 0.0;
+        goto has_float_value;
+        for (; i < RARRAY_LEN(ary); i++) {
+            e = RARRAY_AREF(ary, i);
+            if (block_given)
+                e = rb_yield(e);
+            if (RB_FLOAT_TYPE_P(e))
+              has_float_value:
+                x = RFLOAT_VALUE(e);
+            else if (FIXNUM_P(e))
+                x = FIX2LONG(e);
+            else if (RB_BIGNUM_TYPE_P(e))
+                x = rb_big2dbl(e);
+            else if (RB_TYPE_P(e, T_RATIONAL))
+                x = rb_num2dbl(e);
+            else
+                goto not_float;
+
+            if (isnan(f)) continue;
+            if (isnan(x)) {
+                f = x;
+                continue;
+            }
+            if (isinf(x)) {
+                if (isinf(f) && signbit(x) != signbit(f))
+                    f = NAN;
+                else
+                    f = x;
+                continue;
+            }
+            if (isinf(f)) continue;
+
+            t = f + x;
+            if (fabs(f) >= fabs(x))
+                c += ((f - t) + x);
+            else
+                c += ((x - t) + f);
+            f = t;
+        }
+        f += c;
+        return DBL2NUM(f);
+
+      not_float:
+        v = DBL2NUM(f);
+    }
+
+    goto has_some_value;
+    for (; i < RARRAY_LEN(ary); i++) {
+        e = RARRAY_AREF(ary, i);
+        if (block_given)
+            e = rb_yield(e);
+      has_some_value:
+        v = rb_funcall(v, idPLUS, 1, e);
+    }
+    return v;
+}
+
+static VALUE
+rb_ary_deconstruct(VALUE ary)
+{
+    return ary;
+}
+
+/*
+ *  An \Array is an ordered, integer-indexed collection of objects, called _elements_.
+ *  Any object (even another array) may be an array element,
+ *  and an array can contain objects of different types.
+ *
+ *  == \Array Indexes
+ *
+ *  \Array indexing starts at 0, as in C or Java.
+ *
+ *  A positive index is an offset from the first element:
+ *
+ *  - Index 0 indicates the first element.
+ *  - Index 1 indicates the second element.
+ *  - ...
+ *
+ *  A negative index is an offset, backwards, from the end of the array:
+ *
+ *  - Index -1 indicates the last element.
+ *  - Index -2 indicates the next-to-last element.
+ *  - ...
+ *
+ *  A non-negative index is <i>in range</i> if and only if it is smaller than
+ *  the size of the array.  For a 3-element array:
+ *
+ *  - Indexes 0 through 2 are in range.
+ *  - Index 3 is out of range.
+ *
+ *  A negative index is <i>in range</i> if and only if its absolute value is
+ *  not larger than the size of the array.  For a 3-element array:
+ *
+ *  - Indexes -1 through -3 are in range.
+ *  - Index -4 is out of range.
+ *
+ *  Although the effective index into an array is always an integer,
+ *  some methods (both within and outside of class \Array)
+ *  accept one or more non-integer arguments that are
+ *  {integer-convertible objects}[rdoc-ref:implicit_conversion.rdoc@Integer-Convertible+Objects].
  *
- *  Array indexing starts at 0, as in C or Java.  A negative index is assumed
- *  to be relative to the end of the array---that is, an index of -1 indicates
- *  the last element of the array, -2 is the next to last element in the
- *  array, and so on.
  *
  *  == Creating Arrays
  *
- *  A new array can be created by using the literal constructor
- *  <code>[]</code>.  Arrays can contain different types of objects.  For
- *  example, the array below contains an Integer, a String and a Float:
+ *  You can create an \Array object explicitly with:
+ *
+ *  - An {array literal}[rdoc-ref:literals.rdoc@Array+Literals]:
+ *
+ *      [1, 'one', :one, [2, 'two', :two]]
+ *
+ *  - A {%w or %W: string-array Literal}[rdoc-ref:literals.rdoc@25w+and+-25W-3A+String-Array+Literals]:
+ *
+ *      %w[foo bar baz] # => ["foo", "bar", "baz"]
+ *      %w[1 % *]       # => ["1", "%", "*"]
  *
- *     ary = [1, "two", 3.0] #=> [1, "two", 3.0]
+ *  - A {%i pr %I: symbol-array Literal}[rdoc-ref:literals.rdoc@25i+and+-25I-3A+Symbol-Array+Literals]:
  *
- *  An array can also be created by explicitly calling Array.new with zero, one
- *  (the initial size of the Array) or two arguments (the initial size and a
- *  default object).
+ *      %i[foo bar baz] # => [:foo, :bar, :baz]
+ *      %i[1 % *]       # => [:"1", :%, :*]
  *
- *     ary = Array.new    #=> []
- *     Array.new(3)       #=> [nil, nil, nil]
- *     Array.new(3, true) #=> [true, true, true]
+ *  - \Method Kernel#Array:
  *
- *  Note that the second argument populates the array with references to the
- *  same object.  Therefore, it is only recommended in cases when you need to
- *  instantiate arrays with natively immutable objects such as Symbols,
- *  numbers, true or false.
+ *      Array(["a", "b"])             # => ["a", "b"]
+ *      Array(1..5)                   # => [1, 2, 3, 4, 5]
+ *      Array(key: :value)            # => [[:key, :value]]
+ *      Array(nil)                    # => []
+ *      Array(1)                      # => [1]
+ *      Array({:a => "a", :b => "b"}) # => [[:a, "a"], [:b, "b"]]
  *
- *  To create an array with separate objects a block can be passed instead.
- *  This method is safe to use with mutable objects such as hashes, strings or
- *  other arrays:
+ *  - \Method Array.new:
  *
- *     Array.new(4) { Hash.new } #=> [{}, {}, {}, {}]
+ *      Array.new               # => []
+ *      Array.new(3)            # => [nil, nil, nil]
+ *      Array.new(4) {Hash.new} # => [{}, {}, {}, {}]
+ *      Array.new(3, true)      # => [true, true, true]
  *
- *  This is also a quick way to build up multi-dimensional arrays:
+ *    Note that the last example above populates the array
+ *    with references to the same object.
+ *    This is recommended only in cases where that object is a natively immutable object
+ *    such as a symbol, a numeric, +nil+, +true+, or +false+.
  *
- *     empty_table = Array.new(3) { Array.new(3) }
- *     #=> [[nil, nil, nil], [nil, nil, nil], [nil, nil, nil]]
+ *    Another way to create an array with various objects, using a block;
+ *    this usage is safe for mutable objects such as hashes, strings or
+ *    other arrays:
  *
- *  An array can also be created by using the Array() method, provided by
- *  Kernel, which tries to call #to_ary, then #to_a on its argument.
+ *      Array.new(4) {|i| i.to_s } # => ["0", "1", "2", "3"]
  *
- *	Array({:a => "a", :b => "b"}) #=> [[:a, "a"], [:b, "b"]]
+ *    Here is a way to create a multi-dimensional array:
+ *
+ *      Array.new(3) {Array.new(3)}
+ *      # => [[nil, nil, nil], [nil, nil, nil], [nil, nil, nil]]
+ *
+ *  A number of Ruby methods, both in the core and in the standard library,
+ *  provide instance method +to_a+, which converts an object to an array.
+ *
+ *  - ARGF#to_a
+ *  - Array#to_a
+ *  - Enumerable#to_a
+ *  - Hash#to_a
+ *  - MatchData#to_a
+ *  - NilClass#to_a
+ *  - OptionParser#to_a
+ *  - Range#to_a
+ *  - Set#to_a
+ *  - Struct#to_a
+ *  - Time#to_a
+ *  - Benchmark::Tms#to_a
+ *  - CSV::Table#to_a
+ *  - Enumerator::Lazy#to_a
+ *  - Gem::List#to_a
+ *  - Gem::NameTuple#to_a
+ *  - Gem::Platform#to_a
+ *  - Gem::RequestSet::Lockfile::Tokenizer#to_a
+ *  - Gem::SourceList#to_a
+ *  - OpenSSL::X509::Extension#to_a
+ *  - OpenSSL::X509::Name#to_a
+ *  - Racc::ISet#to_a
+ *  - Rinda::RingFinger#to_a
+ *  - Ripper::Lexer::Elem#to_a
+ *  - RubyVM::InstructionSequence#to_a
+ *  - YAML::DBM#to_a
  *
  *  == Example Usage
  *
  *  In addition to the methods it mixes in through the Enumerable module, the
- *  Array class has proprietary methods for accessing, searching and otherwise
+ *  \Array class has proprietary methods for accessing, searching and otherwise
  *  manipulating arrays.
  *
  *  Some of the more common ones are illustrated below.
@@ -5463,7 +8485,7 @@ rb_ary_drop_while(VALUE ary)
  *
  *     arr.drop(3) #=> [4, 5, 6]
  *
- *  == Obtaining Information about an Array
+ *  == Obtaining Information about an \Array
  *
  *  Arrays keep track of their own length at all times.  To query an array
  *  about the number of elements it contains, use #length, #count or #size.
@@ -5501,7 +8523,7 @@ rb_ary_drop_while(VALUE ary)
  *     arr.insert(3, 'orange', 'pear', 'grapefruit')
  *     #=> [0, 1, 2, "orange", "pear", "grapefruit", "apple", 3, 4, 5, 6]
  *
- *  == Removing Items from an Array
+ *  == Removing Items from an \Array
  *
  *  The method #pop removes the last element in an array and returns it:
  *
@@ -5543,15 +8565,15 @@ rb_ary_drop_while(VALUE ary)
  *
  *  == Iterating over Arrays
  *
- *  Like all classes that include the Enumerable module, Array has an each
+ *  Like all classes that include the Enumerable module, \Array has an each
  *  method, which defines what elements should be iterated over and how.  In
- *  case of Array's #each, all elements in the Array instance are yielded to
+ *  case of Array's #each, all elements in the \Array instance are yielded to
  *  the supplied block in sequence.
  *
  *  Note that this operation leaves the array unchanged.
  *
  *     arr = [1, 2, 3, 4, 5]
- *     arr.each { |a| print a -= 10, " " }
+ *     arr.each {|a| print a -= 10, " "}
  *     # prints: -9 -8 -7 -6 -5
  *     #=> [1, 2, 3, 4, 5]
  *
@@ -5560,18 +8582,19 @@ rb_ary_drop_while(VALUE ary)
  *
  *     words = %w[first second third fourth fifth sixth]
  *     str = ""
- *     words.reverse_each { |word| str += "#{word} " }
+ *     words.reverse_each {|word| str += "#{word} "}
  *     p str #=> "sixth fifth fourth third second first "
  *
  *  The #map method can be used to create a new array based on the original
  *  array, but with the values modified by the supplied block:
  *
- *     arr.map { |a| 2*a }   #=> [2, 4, 6, 8, 10]
+ *     arr.map {|a| 2*a}     #=> [2, 4, 6, 8, 10]
  *     arr                   #=> [1, 2, 3, 4, 5]
- *     arr.map! { |a| a**2 } #=> [1, 4, 9, 16, 25]
+ *     arr.map! {|a| a**2}   #=> [1, 4, 9, 16, 25]
  *     arr                   #=> [1, 4, 9, 16, 25]
  *
- *  == Selecting Items from an Array
+ *
+ *  == Selecting Items from an \Array
  *
  *  Elements can be selected from an array according to criteria defined in a
  *  block.  The selection can happen in a destructive or a non-destructive
@@ -5582,9 +8605,9 @@ rb_ary_drop_while(VALUE ary)
  *  === Non-destructive Selection
  *
  *     arr = [1, 2, 3, 4, 5, 6]
- *     arr.select { |a| a > 3 }     #=> [4, 5, 6]
- *     arr.reject { |a| a < 3 }     #=> [3, 4, 5, 6]
- *     arr.drop_while { |a| a < 4 } #=> [4, 5, 6]
+ *     arr.select {|a| a > 3}       #=> [4, 5, 6]
+ *     arr.reject {|a| a < 3}       #=> [3, 4, 5, 6]
+ *     arr.drop_while {|a| a < 4}   #=> [4, 5, 6]
  *     arr                          #=> [1, 2, 3, 4, 5, 6]
  *
  *  === Destructive Selection
@@ -5595,25 +8618,205 @@ rb_ary_drop_while(VALUE ary)
  *  Similar to #select vs. #reject, #delete_if and #keep_if have the exact
  *  opposite result when supplied with the same block:
  *
- *     arr.delete_if { |a| a < 4 } #=> [4, 5, 6]
+ *     arr.delete_if {|a| a < 4}   #=> [4, 5, 6]
  *     arr                         #=> [4, 5, 6]
  *
  *     arr = [1, 2, 3, 4, 5, 6]
- *     arr.keep_if { |a| a < 4 } #=> [1, 2, 3]
+ *     arr.keep_if {|a| a < 4}   #=> [1, 2, 3]
  *     arr                       #=> [1, 2, 3]
  *
+ *  == What's Here
+ *
+ *  First, what's elsewhere. \Class \Array:
+ *
+ *  - Inherits from {class Object}[rdoc-ref:Object@What-27s+Here].
+ *  - Includes {module Enumerable}[rdoc-ref:Enumerable@What-27s+Here],
+ *    which provides dozens of additional methods.
+ *
+ *  Here, class \Array provides methods that are useful for:
+ *
+ *  - {Creating an Array}[rdoc-ref:Array@Methods+for+Creating+an+Array]
+ *  - {Querying}[rdoc-ref:Array@Methods+for+Querying]
+ *  - {Comparing}[rdoc-ref:Array@Methods+for+Comparing]
+ *  - {Fetching}[rdoc-ref:Array@Methods+for+Fetching]
+ *  - {Assigning}[rdoc-ref:Array@Methods+for+Assigning]
+ *  - {Deleting}[rdoc-ref:Array@Methods+for+Deleting]
+ *  - {Combining}[rdoc-ref:Array@Methods+for+Combining]
+ *  - {Iterating}[rdoc-ref:Array@Methods+for+Iterating]
+ *  - {Converting}[rdoc-ref:Array@Methods+for+Converting]
+ *  - {And more....}[rdoc-ref:Array@Other+Methods]
+ *
+ *  === Methods for Creating an \Array
+ *
+ *  - ::[]: Returns a new array populated with given objects.
+ *  - ::new: Returns a new array.
+ *  - ::try_convert: Returns a new array created from a given object.
+ *
+ *  === Methods for Querying
+ *
+ *  - #length, #size: Returns the count of elements.
+ *  - #include?: Returns whether any element <tt>==</tt> a given object.
+ *  - #empty?: Returns whether there are no elements.
+ *  - #all?: Returns whether all elements meet a given criterion.
+ *  - #any?: Returns whether any element meets a given criterion.
+ *  - #none?: Returns whether no element <tt>==</tt> a given object.
+ *  - #one?: Returns whether exactly one element <tt>==</tt> a given object.
+ *  - #count: Returns the count of elements that meet a given criterion.
+ *  - #find_index, #index: Returns the index of the first element that meets a given criterion.
+ *  - #rindex: Returns the index of the last element that meets a given criterion.
+ *  - #hash: Returns the integer hash code.
+ *
+ *  === Methods for Comparing
+ *
+ *  - #<=>: Returns -1, 0, or 1 * as +self+ is less than, equal to, or
+ *    greater than a given object.
+ *  - #==: Returns whether each element in +self+ is <tt>==</tt> to the corresponding element
+ *    in a given object.
+ *  - #eql?: Returns whether each element in +self+ is <tt>eql?</tt> to the corresponding
+ *    element in a given object.
+
+ *  === Methods for Fetching
+ *
+ *  These methods do not modify +self+.
+ *
+ *  - #[]: Returns one or more elements.
+ *  - #fetch: Returns the element at a given offset.
+ *  - #first: Returns one or more leading elements.
+ *  - #last: Returns one or more trailing elements.
+ *  - #max: Returns one or more maximum-valued elements,
+ *    as determined by <tt><=></tt> or a given block.
+ *  - #min: Returns one or more minimum-valued elements,
+ *    as determined by <tt><=></tt> or a given block.
+ *  - #minmax: Returns the minimum-valued and maximum-valued elements,
+ *    as determined by <tt><=></tt> or a given block.
+ *  - #assoc: Returns the first element that is an array
+ *    whose first element <tt>==</tt> a given object.
+ *  - #rassoc: Returns the first element that is an array
+ *    whose second element <tt>==</tt> a given object.
+ *  - #at: Returns the element at a given offset.
+ *  - #values_at: Returns the elements at given offsets.
+ *  - #dig: Returns the object in nested objects
+ *    that is specified by a given index and additional arguments.
+ *  - #drop: Returns trailing elements as determined by a given index.
+ *  - #take: Returns leading elements as determined by a given index.
+ *  - #drop_while: Returns trailing elements as determined by a given block.
+ *  - #take_while: Returns leading elements as determined by a given block.
+ *  - #slice: Returns consecutive elements as determined by a given argument.
+ *  - #sort: Returns all elements in an order determined by <tt><=></tt> or a given block.
+ *  - #reverse: Returns all elements in reverse order.
+ *  - #compact: Returns an array containing all non-+nil+ elements.
+ *  - #select, #filter: Returns an array containing elements selected by a given block.
+ *  - #uniq: Returns an array containing non-duplicate elements.
+ *  - #rotate: Returns all elements with some rotated from one end to the other.
+ *  - #bsearch: Returns an element selected via a binary search
+ *    as determined by a given block.
+ *  - #bsearch_index: Returns the index of an element selected via a binary search
+ *    as determined by a given block.
+ *  - #sample: Returns one or more random elements.
+ *  - #shuffle: Returns elements in a random order.
+ *
+ *  === Methods for Assigning
+ *
+ *  These methods add, replace, or reorder elements in +self+.
+ *
+ *  - #[]=: Assigns specified elements with a given object.
+ *  - #push, #append, #<<: Appends trailing elements.
+ *  - #unshift, #prepend: Prepends leading elements.
+ *  - #insert: Inserts given objects at a given offset; does not replace elements.
+ *  - #concat: Appends all elements from given arrays.
+ *  - #fill: Replaces specified elements with specified objects.
+ *  - #replace: Replaces the content of +self+ with the content of a given array.
+ *  - #reverse!: Replaces +self+ with its elements reversed.
+ *  - #rotate!: Replaces +self+ with its elements rotated.
+ *  - #shuffle!: Replaces +self+ with its elements in random order.
+ *  - #sort!: Replaces +self+ with its elements sorted,
+ *    as determined by <tt><=></tt> or a given block.
+ *  - #sort_by!: Replaces +self+ with its elements sorted, as determined by a given block.
+ *
+ *  === Methods for Deleting
+ *
+ *  Each of these methods removes elements from +self+:
+ *
+ *  - #pop: Removes and returns the last element.
+ *  - #shift:  Removes and returns the first element.
+ *  - #compact!: Removes all +nil+ elements.
+ *  - #delete: Removes elements equal to a given object.
+ *  - #delete_at: Removes the element at a given offset.
+ *  - #delete_if: Removes elements specified by a given block.
+ *  - #keep_if: Removes elements not specified by a given block.
+ *  - #reject!: Removes elements specified by a given block.
+ *  - #select!, #filter!: Removes elements not specified by a given block.
+ *  - #slice!: Removes and returns a sequence of elements.
+ *  - #uniq!: Removes duplicates.
+ *
+ *  === Methods for Combining
+ *
+ *  - #&: Returns an array containing elements found both in +self+ and a given array.
+ *  - #intersection: Returns an array containing elements found both in +self+
+ *    and in each given array.
+ *  - #+: Returns an array containing all elements of +self+ followed by all elements of a given array.
+ *  - #-: Returns an array containing all elements of +self+ that are not found in a given array.
+ *  - #|: Returns an array containing all elements of +self+ and all elements of a given array,
+ *    duplicates removed.
+ *  - #union: Returns an array containing all elements of +self+ and all elements of given arrays,
+ *    duplicates removed.
+ *  - #difference: Returns an array containing all elements of +self+ that are not found
+ *    in any of the given arrays..
+ *  - #product: Returns or yields all combinations of elements from +self+ and given arrays.
+ *
+ *  === Methods for Iterating
+ *
+ *  - #each: Passes each element to a given block.
+ *  - #reverse_each:  Passes each element, in reverse order, to a given block.
+ *  - #each_index: Passes each element index to a given block.
+ *  - #cycle: Calls a given block with each element, then does so again,
+ *    for a specified number of times, or forever.
+ *  - #combination: Calls a given block with combinations of elements of +self+;
+ *    a combination does not use the same element more than once.
+ *  - #permutation: Calls a given block with permutations of elements of +self+;
+ *    a permutation does not use the same element more than once.
+ *  - #repeated_combination: Calls a given block with combinations of elements of +self+;
+ *    a combination may use the same element more than once.
+ *  - #repeated_permutation: Calls a given block with permutations of elements of +self+;
+ *    a permutation may use the same element more than once.
+ *
+ *  === Methods for Converting
+ *
+ *  - #map, #collect: Returns an array containing the block return-value for each element.
+ *  - #map!, #collect!: Replaces each element with a block return-value.
+ *  - #flatten: Returns an array that is a recursive flattening of +self+.
+ *  - #flatten!: Replaces each nested array in +self+ with the elements from that array.
+ *  - #inspect, #to_s: Returns a new String containing the elements.
+ *  - #join: Returns a newsString containing the elements joined by the field separator.
+ *  - #to_a: Returns +self+ or a new array containing all elements.
+ *  - #to_ary: Returns +self+.
+ *  - #to_h: Returns a new hash formed from the elements.
+ *  - #transpose: Transposes +self+, which must be an array of arrays.
+ *  - #zip: Returns a new array of arrays containing +self+ and given arrays;
+ *    follow the link for details.
+ *
+ *  === Other Methods
+ *
+ *  - #*: Returns one of the following:
+ *
+ *    - With integer argument +n+, a new array that is the concatenation
+ *      of +n+ copies of +self+.
+ *    - With string argument +field_separator+, a new string that is equivalent to
+ *      <tt>join(field_separator)</tt>.
+ *
+ *  - #abbrev: Returns a hash of unambiguous abbreviations for elements.
+ *  - #pack: Packs the elements into a binary sequence.
+ *  - #sum: Returns a sum of elements according to either <tt>+</tt> or a given block.
  */
 
 void
 Init_Array(void)
 {
-#undef rb_intern
-#define rb_intern(str) rb_intern_const(str)
-
     rb_cArray  = rb_define_class("Array", rb_cObject);
     rb_include_module(rb_cArray, rb_mEnumerable);
 
     rb_define_alloc_func(rb_cArray, empty_ary_alloc);
+    rb_define_singleton_method(rb_cArray, "new", rb_ary_s_new, -1);
     rb_define_singleton_method(rb_cArray, "[]", rb_ary_s_create, -1);
     rb_define_singleton_method(rb_cArray, "try_convert", rb_ary_s_try_convert, 1);
     rb_define_method(rb_cArray, "initialize", rb_ary_initialize, -1);
@@ -5624,7 +8827,6 @@ Init_Array(void)
     rb_define_method(rb_cArray, "to_a", rb_ary_to_a, 0);
     rb_define_method(rb_cArray, "to_h", rb_ary_to_h, 0);
     rb_define_method(rb_cArray, "to_ary", rb_ary_to_ary_m, 0);
-    rb_define_method(rb_cArray, "frozen?",  rb_ary_frozen_p, 0);
 
     rb_define_method(rb_cArray, "==", rb_ary_equal, 1);
     rb_define_method(rb_cArray, "eql?", rb_ary_eql, 1);
@@ -5636,18 +8838,24 @@ Init_Array(void)
     rb_define_method(rb_cArray, "fetch", rb_ary_fetch, -1);
     rb_define_method(rb_cArray, "first", rb_ary_first, -1);
     rb_define_method(rb_cArray, "last", rb_ary_last, -1);
-    rb_define_method(rb_cArray, "concat", rb_ary_concat, 1);
+    rb_define_method(rb_cArray, "concat", rb_ary_concat_multi, -1);
+    rb_define_method(rb_cArray, "union", rb_ary_union_multi, -1);
+    rb_define_method(rb_cArray, "difference", rb_ary_difference_multi, -1);
+    rb_define_method(rb_cArray, "intersection", rb_ary_intersection_multi, -1);
+    rb_define_method(rb_cArray, "intersect?", rb_ary_intersect_p, 1);
     rb_define_method(rb_cArray, "<<", rb_ary_push, 1);
     rb_define_method(rb_cArray, "push", rb_ary_push_m, -1);
+    rb_define_alias(rb_cArray,  "append", "push");
     rb_define_method(rb_cArray, "pop", rb_ary_pop_m, -1);
     rb_define_method(rb_cArray, "shift", rb_ary_shift_m, -1);
     rb_define_method(rb_cArray, "unshift", rb_ary_unshift_m, -1);
+    rb_define_alias(rb_cArray,  "prepend", "unshift");
     rb_define_method(rb_cArray, "insert", rb_ary_insert, -1);
     rb_define_method(rb_cArray, "each", rb_ary_each, 0);
     rb_define_method(rb_cArray, "each_index", rb_ary_each_index, 0);
     rb_define_method(rb_cArray, "reverse_each", rb_ary_reverse_each, 0);
     rb_define_method(rb_cArray, "length", rb_ary_length, 0);
-    rb_define_alias(rb_cArray,  "size", "length");
+    rb_define_method(rb_cArray, "size", rb_ary_length, 0);
     rb_define_method(rb_cArray, "empty?", rb_ary_empty_p, 0);
     rb_define_method(rb_cArray, "find_index", rb_ary_index, -1);
     rb_define_method(rb_cArray, "index", rb_ary_index, -1);
@@ -5666,6 +8874,8 @@ Init_Array(void)
     rb_define_method(rb_cArray, "map!", rb_ary_collect_bang, 0);
     rb_define_method(rb_cArray, "select", rb_ary_select, 0);
     rb_define_method(rb_cArray, "select!", rb_ary_select_bang, 0);
+    rb_define_method(rb_cArray, "filter", rb_ary_select, 0);
+    rb_define_method(rb_cArray, "filter!", rb_ary_select_bang, 0);
     rb_define_method(rb_cArray, "keep_if", rb_ary_keep_if, 0);
     rb_define_method(rb_cArray, "values_at", rb_ary_values_at, -1);
     rb_define_method(rb_cArray, "delete", rb_ary_delete, 1);
@@ -5694,6 +8904,10 @@ Init_Array(void)
     rb_define_method(rb_cArray, "&", rb_ary_and, 1);
     rb_define_method(rb_cArray, "|", rb_ary_or, 1);
 
+    rb_define_method(rb_cArray, "max", rb_ary_max, -1);
+    rb_define_method(rb_cArray, "min", rb_ary_min, -1);
+    rb_define_method(rb_cArray, "minmax", rb_ary_minmax, 0);
+
     rb_define_method(rb_cArray, "uniq", rb_ary_uniq, 0);
     rb_define_method(rb_cArray, "uniq!", rb_ary_uniq_bang, 0);
     rb_define_method(rb_cArray, "compact", rb_ary_compact, 0);
@@ -5701,9 +8915,6 @@ Init_Array(void)
     rb_define_method(rb_cArray, "flatten", rb_ary_flatten, -1);
     rb_define_method(rb_cArray, "flatten!", rb_ary_flatten_bang, -1);
     rb_define_method(rb_cArray, "count", rb_ary_count, -1);
-    rb_define_method(rb_cArray, "shuffle!", rb_ary_shuffle_bang, -1);
-    rb_define_method(rb_cArray, "shuffle", rb_ary_shuffle, -1);
-    rb_define_method(rb_cArray, "sample", rb_ary_sample, -1);
     rb_define_method(rb_cArray, "cycle", rb_ary_cycle, -1);
     rb_define_method(rb_cArray, "permutation", rb_ary_permutation, -1);
     rb_define_method(rb_cArray, "combination", rb_ary_combination, 1);
@@ -5716,9 +8927,15 @@ Init_Array(void)
     rb_define_method(rb_cArray, "drop", rb_ary_drop, 1);
     rb_define_method(rb_cArray, "drop_while", rb_ary_drop_while, 0);
     rb_define_method(rb_cArray, "bsearch", rb_ary_bsearch, 0);
+    rb_define_method(rb_cArray, "bsearch_index", rb_ary_bsearch_index, 0);
+    rb_define_method(rb_cArray, "any?", rb_ary_any_p, -1);
+    rb_define_method(rb_cArray, "all?", rb_ary_all_p, -1);
+    rb_define_method(rb_cArray, "none?", rb_ary_none_p, -1);
+    rb_define_method(rb_cArray, "one?", rb_ary_one_p, -1);
+    rb_define_method(rb_cArray, "dig", rb_ary_dig, -1);
+    rb_define_method(rb_cArray, "sum", rb_ary_sum, -1);
 
-    id_cmp = rb_intern("<=>");
-    id_random = rb_intern("random");
-    id_div = rb_intern("div");
-    id_power = rb_intern("**");
+    rb_define_method(rb_cArray, "deconstruct", rb_ary_deconstruct, 0);
 }
+
+#include "array.rbinc"
diff --git a/array.rb b/array.rb
new file mode 100644
index 0000000000..b9fa9844e6
--- /dev/null
+++ b/array.rb
@@ -0,0 +1,69 @@
+class Array
+  # call-seq:
+  #    array.shuffle!(random: Random) -> array
+  #
+  # Shuffles the elements of +self+ in place.
+  #    a = [1, 2, 3] #=> [1, 2, 3]
+  #    a.shuffle!    #=> [2, 3, 1]
+  #    a             #=> [2, 3, 1]
+  #
+  # The optional +random+ argument will be used as the random number generator:
+  #    a.shuffle!(random: Random.new(1))  #=> [1, 3, 2]
+  def shuffle!(random: Random)
+    Primitive.rb_ary_shuffle_bang(random)
+  end
+
+  # call-seq:
+  #    array.shuffle(random: Random) -> new_ary
+  #
+  # Returns a new array with elements of +self+ shuffled.
+  #    a = [1, 2, 3] #=> [1, 2, 3]
+  #    a.shuffle     #=> [2, 3, 1]
+  #    a             #=> [1, 2, 3]
+  #
+  # The optional +random+ argument will be used as the random number generator:
+  #    a.shuffle(random: Random.new(1))  #=> [1, 3, 2]
+  def shuffle(random: Random)
+    Primitive.rb_ary_shuffle(random)
+  end
+
+  # call-seq:
+  #    array.sample(random: Random) -> object
+  #    array.sample(n, random: Random) -> new_ary
+  #
+  # Returns random elements from +self+.
+  #
+  # When no arguments are given, returns a random element from +self+:
+  #    a = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+  #    a.sample # => 3
+  #    a.sample # => 8
+  # If +self+ is empty, returns +nil+.
+  #
+  # When argument +n+ is given, returns a new \Array containing +n+ random
+  # elements from +self+:
+  #    a.sample(3) # => [8, 9, 2]
+  #    a.sample(6) # => [9, 6, 10, 3, 1, 4]
+  # Returns no more than <tt>a.size</tt> elements
+  # (because no new duplicates are introduced):
+  #    a.sample(a.size * 2) # => [6, 4, 1, 8, 5, 9, 10, 2, 3, 7]
+  # But +self+ may contain duplicates:
+  #    a = [1, 1, 1, 2, 2, 3]
+  #    a.sample(a.size * 2) # => [1, 1, 3, 2, 1, 2]
+  # The argument +n+ must be a non-negative numeric value.
+  # The order of the result array is unrelated to the order of +self+.
+  # Returns a new empty \Array if +self+ is empty.
+  #
+  # The optional +random+ argument will be used as the random number generator:
+  #    a = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+  #    a.sample(random: Random.new(1))     #=> 6
+  #    a.sample(4, random: Random.new(1))  #=> [6, 10, 9, 2]
+  def sample(n = (ary = false), random: Random)
+    if Primitive.mandatory_only?
+      # Primitive.cexpr! %{ rb_ary_sample(self, rb_cRandom, Qfalse, Qfalse) }
+      Primitive.ary_sample0
+    else
+      # Primitive.cexpr! %{ rb_ary_sample(self, random, n, ary) }
+      Primitive.ary_sample(random, n, ary)
+    end
+  end
+end
diff --git a/ast.c b/ast.c
new file mode 100644
index 0000000000..adb7287ed3
--- /dev/null
+++ b/ast.c
@@ -0,0 +1,773 @@
+/* indent-tabs-mode: nil */
+#include "internal.h"
+#include "internal/parse.h"
+#include "internal/symbol.h"
+#include "internal/warnings.h"
+#include "iseq.h"
+#include "node.h"
+#include "ruby.h"
+#include "ruby/encoding.h"
+#include "ruby/util.h"
+#include "vm_core.h"
+
+#include "builtin.h"
+
+static VALUE rb_mAST;
+static VALUE rb_cNode;
+
+struct ASTNodeData {
+    rb_ast_t *ast;
+    const NODE *node;
+};
+
+static void
+node_gc_mark(void *ptr)
+{
+    struct ASTNodeData *data = (struct ASTNodeData *)ptr;
+    rb_gc_mark((VALUE)data->ast);
+}
+
+static size_t
+node_memsize(const void *ptr)
+{
+    struct ASTNodeData *data = (struct ASTNodeData *)ptr;
+    return rb_ast_memsize(data->ast);
+}
+
+static const rb_data_type_t rb_node_type = {
+    "AST/node",
+    {node_gc_mark, RUBY_TYPED_DEFAULT_FREE, node_memsize,},
+    0, 0,
+    RUBY_TYPED_FREE_IMMEDIATELY,
+};
+
+static VALUE rb_ast_node_alloc(VALUE klass);
+
+static void
+setup_node(VALUE obj, rb_ast_t *ast, const NODE *node)
+{
+    struct ASTNodeData *data;
+
+    TypedData_Get_Struct(obj, struct ASTNodeData, &rb_node_type, data);
+    data->ast = ast;
+    data->node = node;
+}
+
+static VALUE
+ast_new_internal(rb_ast_t *ast, const NODE *node)
+{
+    VALUE obj;
+
+    obj = rb_ast_node_alloc(rb_cNode);
+    setup_node(obj, ast, node);
+
+    return obj;
+}
+
+static VALUE rb_ast_parse_str(VALUE str, VALUE keep_script_lines, VALUE error_tolerant, VALUE keep_tokens);
+static VALUE rb_ast_parse_file(VALUE path, VALUE keep_script_lines, VALUE error_tolerant, VALUE keep_tokens);
+
+static VALUE
+ast_parse_new(void)
+{
+    return rb_parser_set_context(rb_parser_new(), NULL, 0);
+}
+
+static VALUE
+ast_parse_done(rb_ast_t *ast)
+{
+    if (!ast->body.root) {
+        rb_ast_dispose(ast);
+        rb_exc_raise(GET_EC()->errinfo);
+    }
+
+    return ast_new_internal(ast, (NODE *)ast->body.root);
+}
+
+static VALUE
+ast_s_parse(rb_execution_context_t *ec, VALUE module, VALUE str, VALUE keep_script_lines, VALUE error_tolerant, VALUE keep_tokens)
+{
+    return rb_ast_parse_str(str, keep_script_lines, error_tolerant, keep_tokens);
+}
+
+static VALUE
+rb_ast_parse_str(VALUE str, VALUE keep_script_lines, VALUE error_tolerant, VALUE keep_tokens)
+{
+    rb_ast_t *ast = 0;
+
+    StringValue(str);
+    VALUE vparser = ast_parse_new();
+    if (RTEST(keep_script_lines)) rb_parser_keep_script_lines(vparser);
+    if (RTEST(error_tolerant)) rb_parser_error_tolerant(vparser);
+    if (RTEST(keep_tokens)) rb_parser_keep_tokens(vparser);
+    ast = rb_parser_compile_string_path(vparser, Qnil, str, 1);
+    return ast_parse_done(ast);
+}
+
+static VALUE
+ast_s_parse_file(rb_execution_context_t *ec, VALUE module, VALUE path, VALUE keep_script_lines, VALUE error_tolerant, VALUE keep_tokens)
+{
+    return rb_ast_parse_file(path, keep_script_lines, error_tolerant, keep_tokens);
+}
+
+static VALUE
+rb_ast_parse_file(VALUE path, VALUE keep_script_lines, VALUE error_tolerant, VALUE keep_tokens)
+{
+    VALUE f;
+    rb_ast_t *ast = 0;
+    rb_encoding *enc = rb_utf8_encoding();
+
+    FilePathValue(path);
+    f = rb_file_open_str(path, "r");
+    rb_funcall(f, rb_intern("set_encoding"), 2, rb_enc_from_encoding(enc), rb_str_new_cstr("-"));
+    VALUE vparser = ast_parse_new();
+    if (RTEST(keep_script_lines)) rb_parser_keep_script_lines(vparser);
+    if (RTEST(error_tolerant))  rb_parser_error_tolerant(vparser);
+    if (RTEST(keep_tokens))  rb_parser_keep_tokens(vparser);
+    ast = rb_parser_compile_file_path(vparser, Qnil, f, 1);
+    rb_io_close(f);
+    return ast_parse_done(ast);
+}
+
+static VALUE
+lex_array(VALUE array, int index)
+{
+    VALUE str = rb_ary_entry(array, index);
+    if (!NIL_P(str)) {
+        StringValue(str);
+        if (!rb_enc_asciicompat(rb_enc_get(str))) {
+            rb_raise(rb_eArgError, "invalid source encoding");
+        }
+    }
+    return str;
+}
+
+static VALUE
+rb_ast_parse_array(VALUE array, VALUE keep_script_lines, VALUE error_tolerant, VALUE keep_tokens)
+{
+    rb_ast_t *ast = 0;
+
+    array = rb_check_array_type(array);
+    VALUE vparser = ast_parse_new();
+    if (RTEST(keep_script_lines)) rb_parser_keep_script_lines(vparser);
+    if (RTEST(error_tolerant)) rb_parser_error_tolerant(vparser);
+    if (RTEST(keep_tokens)) rb_parser_keep_tokens(vparser);
+    ast = rb_parser_compile_generic(vparser, lex_array, Qnil, array, 1);
+    return ast_parse_done(ast);
+}
+
+static VALUE node_children(rb_ast_t*, const NODE*);
+
+static VALUE
+node_find(VALUE self, const int node_id)
+{
+    VALUE ary;
+    long i;
+    struct ASTNodeData *data;
+    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);
+
+    if (nd_node_id(data->node) == node_id) return self;
+
+    ary = node_children(data->ast, data->node);
+
+    for (i = 0; i < RARRAY_LEN(ary); i++) {
+        VALUE child = RARRAY_AREF(ary, i);
+
+        if (CLASS_OF(child) == rb_cNode) {
+            VALUE result = node_find(child, node_id);
+            if (RTEST(result)) return result;
+        }
+    }
+
+    return Qnil;
+}
+
+extern VALUE rb_e_script;
+
+static VALUE
+script_lines(VALUE path)
+{
+    VALUE hash, lines;
+    ID script_lines;
+    CONST_ID(script_lines, "SCRIPT_LINES__");
+    if (!rb_const_defined_at(rb_cObject, script_lines)) return Qnil;
+    hash = rb_const_get_at(rb_cObject, script_lines);
+    if (!RB_TYPE_P(hash, T_HASH)) return Qnil;
+    lines = rb_hash_lookup(hash, path);
+    if (!RB_TYPE_P(lines, T_ARRAY)) return Qnil;
+    return lines;
+}
+
+static VALUE
+node_id_for_backtrace_location(rb_execution_context_t *ec, VALUE module, VALUE location)
+{
+    int node_id;
+
+    if (!rb_frame_info_p(location)) {
+        rb_raise(rb_eTypeError, "Thread::Backtrace::Location object expected");
+    }
+
+    node_id = rb_get_node_id_from_frame_info(location);
+    if (node_id == -1) {
+        return Qnil;
+    }
+
+    return INT2NUM(node_id);
+}
+
+static VALUE
+ast_s_of(rb_execution_context_t *ec, VALUE module, VALUE body, VALUE keep_script_lines, VALUE error_tolerant, VALUE keep_tokens)
+{
+    VALUE node, lines = Qnil;
+    const rb_iseq_t *iseq;
+    int node_id;
+
+    if (rb_frame_info_p(body)) {
+        iseq = rb_get_iseq_from_frame_info(body);
+        node_id = rb_get_node_id_from_frame_info(body);
+    }
+    else {
+        iseq = NULL;
+
+        if (rb_obj_is_proc(body)) {
+            iseq = vm_proc_iseq(body);
+
+            if (!rb_obj_is_iseq((VALUE)iseq)) return Qnil;
+        }
+        else {
+            iseq = rb_method_iseq(body);
+        }
+        if (iseq) {
+            node_id = ISEQ_BODY(iseq)->location.node_id;
+        }
+    }
+
+    if (!iseq) {
+        return Qnil;
+    }
+    lines = ISEQ_BODY(iseq)->variable.script_lines;
+
+    VALUE path = rb_iseq_path(iseq);
+    int e_option = RSTRING_LEN(path) == 2 && memcmp(RSTRING_PTR(path), "-e", 2) == 0;
+
+    if (NIL_P(lines) && rb_iseq_from_eval_p(iseq) && !e_option) {
+        rb_raise(rb_eArgError, "cannot get AST for method defined in eval");
+    }
+
+    if (!NIL_P(lines) || !NIL_P(lines = script_lines(path))) {
+        node = rb_ast_parse_array(lines, keep_script_lines, error_tolerant, keep_tokens);
+    }
+    else if (e_option) {
+        node = rb_ast_parse_str(rb_e_script, keep_script_lines, error_tolerant, keep_tokens);
+    }
+    else {
+        node = rb_ast_parse_file(path, keep_script_lines, error_tolerant, keep_tokens);
+    }
+
+    return node_find(node, node_id);
+}
+
+static VALUE
+rb_ast_node_alloc(VALUE klass)
+{
+    struct ASTNodeData *data;
+    VALUE obj = TypedData_Make_Struct(klass, struct ASTNodeData, &rb_node_type, data);
+
+    return obj;
+}
+
+static const char*
+node_type_to_str(const NODE *node)
+{
+    return (ruby_node_name(nd_type(node)) + rb_strlen_lit("NODE_"));
+}
+
+static VALUE
+ast_node_type(rb_execution_context_t *ec, VALUE self)
+{
+    struct ASTNodeData *data;
+    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);
+
+    return rb_sym_intern_ascii_cstr(node_type_to_str(data->node));
+}
+
+static VALUE
+ast_node_node_id(rb_execution_context_t *ec, VALUE self)
+{
+    struct ASTNodeData *data;
+    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);
+
+    return INT2FIX(nd_node_id(data->node));
+}
+
+#define NEW_CHILD(ast, node) node ? ast_new_internal(ast, node) : Qnil
+
+static VALUE
+rb_ary_new_from_node_args(rb_ast_t *ast, long n, ...)
+{
+    va_list ar;
+    VALUE ary;
+    long i;
+
+    ary = rb_ary_new2(n);
+
+    va_start(ar, n);
+    for (i=0; i<n; i++) {
+        NODE *node;
+        node = va_arg(ar, NODE *);
+        rb_ary_push(ary, NEW_CHILD(ast, node));
+    }
+    va_end(ar);
+    return ary;
+}
+
+static VALUE
+dump_block(rb_ast_t *ast, const NODE *node)
+{
+    VALUE ary = rb_ary_new();
+    do {
+        rb_ary_push(ary, NEW_CHILD(ast, node->nd_head));
+    } while (node->nd_next &&
+        nd_type_p(node->nd_next, NODE_BLOCK) &&
+        (node = node->nd_next, 1));
+    if (node->nd_next) {
+        rb_ary_push(ary, NEW_CHILD(ast, node->nd_next));
+    }
+
+    return ary;
+}
+
+static VALUE
+dump_array(rb_ast_t *ast, const NODE *node)
+{
+    VALUE ary = rb_ary_new();
+    rb_ary_push(ary, NEW_CHILD(ast, node->nd_head));
+
+    while (node->nd_next && nd_type_p(node->nd_next, NODE_LIST)) {
+        node = node->nd_next;
+        rb_ary_push(ary, NEW_CHILD(ast, node->nd_head));
+    }
+    rb_ary_push(ary, NEW_CHILD(ast, node->nd_next));
+
+    return ary;
+}
+
+static VALUE
+var_name(ID id)
+{
+    if (!id) return Qnil;
+    if (!rb_id2str(id)) return Qnil;
+    return ID2SYM(id);
+}
+
+static VALUE
+no_name_rest(void)
+{
+    ID rest;
+    CONST_ID(rest, "NODE_SPECIAL_NO_NAME_REST");
+    return ID2SYM(rest);
+}
+
+static VALUE
+rest_arg(rb_ast_t *ast, const NODE *rest_arg)
+{
+    return NODE_NAMED_REST_P(rest_arg) ? NEW_CHILD(ast, rest_arg) : no_name_rest();
+}
+
+static VALUE
+node_children(rb_ast_t *ast, const NODE *node)
+{
+    char name[DECIMAL_SIZE_OF_BITS(sizeof(long) * CHAR_BIT) + 2]; /* including '$' */
+
+    enum node_type type = nd_type(node);
+    switch (type) {
+      case NODE_BLOCK:
+        return dump_block(ast, node);
+      case NODE_IF:
+        return rb_ary_new_from_node_args(ast, 3, node->nd_cond, node->nd_body, node->nd_else);
+      case NODE_UNLESS:
+        return rb_ary_new_from_node_args(ast, 3, node->nd_cond, node->nd_body, node->nd_else);
+      case NODE_CASE:
+        return rb_ary_new_from_node_args(ast, 2, node->nd_head, node->nd_body);
+      case NODE_CASE2:
+        return rb_ary_new_from_node_args(ast, 2, node->nd_head, node->nd_body);
+      case NODE_CASE3:
+        return rb_ary_new_from_node_args(ast, 2, node->nd_head, node->nd_body);
+      case NODE_WHEN:
+        return rb_ary_new_from_node_args(ast, 3, node->nd_head, node->nd_body, node->nd_next);
+      case NODE_IN:
+        return rb_ary_new_from_node_args(ast, 3, node->nd_head, node->nd_body, node->nd_next);
+      case NODE_WHILE:
+      case NODE_UNTIL:
+        return rb_ary_push(rb_ary_new_from_node_args(ast, 2, node->nd_cond, node->nd_body),
+                           RBOOL(node->nd_state));
+      case NODE_ITER:
+      case NODE_FOR:
+        return rb_ary_new_from_node_args(ast, 2, node->nd_iter, node->nd_body);
+      case NODE_FOR_MASGN:
+        return rb_ary_new_from_node_args(ast, 1, node->nd_var);
+      case NODE_BREAK:
+      case NODE_NEXT:
+      case NODE_RETURN:
+        return rb_ary_new_from_node_args(ast, 1, node->nd_stts);
+      case NODE_REDO:
+        return rb_ary_new_from_node_args(ast, 0);
+      case NODE_RETRY:
+        return rb_ary_new_from_node_args(ast, 0);
+      case NODE_BEGIN:
+        return rb_ary_new_from_node_args(ast, 1, node->nd_body);
+      case NODE_RESCUE:
+        return rb_ary_new_from_node_args(ast, 3, node->nd_head, node->nd_resq, node->nd_else);
+      case NODE_RESBODY:
+        return rb_ary_new_from_node_args(ast, 3, node->nd_args, node->nd_body, node->nd_head);
+      case NODE_ENSURE:
+        return rb_ary_new_from_node_args(ast, 2, node->nd_head, node->nd_ensr);
+      case NODE_AND:
+      case NODE_OR:
+        {
+            VALUE ary = rb_ary_new();
+
+            while (1) {
+                rb_ary_push(ary, NEW_CHILD(ast, node->nd_1st));
+                if (!node->nd_2nd || !nd_type_p(node->nd_2nd, type))
+                    break;
+                node = node->nd_2nd;
+            }
+            rb_ary_push(ary, NEW_CHILD(ast, node->nd_2nd));
+            return ary;
+        }
+      case NODE_MASGN:
+        if (NODE_NAMED_REST_P(node->nd_args)) {
+            return rb_ary_new_from_node_args(ast, 3, node->nd_value, node->nd_head, node->nd_args);
+        }
+        else {
+            return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_value),
+                                        NEW_CHILD(ast, node->nd_head),
+                                        no_name_rest());
+        }
+      case NODE_LASGN:
+      case NODE_DASGN:
+      case NODE_IASGN:
+      case NODE_CVASGN:
+      case NODE_GASGN:
+        if (NODE_REQUIRED_KEYWORD_P(node)) {
+            return rb_ary_new_from_args(2, var_name(node->nd_vid), ID2SYM(rb_intern("NODE_SPECIAL_REQUIRED_KEYWORD")));
+        }
+        return rb_ary_new_from_args(2, var_name(node->nd_vid), NEW_CHILD(ast, node->nd_value));
+      case NODE_CDECL:
+        if (node->nd_vid) {
+            return rb_ary_new_from_args(2, ID2SYM(node->nd_vid), NEW_CHILD(ast, node->nd_value));
+        }
+        return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_else), ID2SYM(node->nd_else->nd_mid), NEW_CHILD(ast, node->nd_value));
+      case NODE_OP_ASGN1:
+        return rb_ary_new_from_args(4, NEW_CHILD(ast, node->nd_recv),
+                                    ID2SYM(node->nd_mid),
+                                    NEW_CHILD(ast, node->nd_args->nd_head),
+                                    NEW_CHILD(ast, node->nd_args->nd_body));
+      case NODE_OP_ASGN2:
+        return rb_ary_new_from_args(5, NEW_CHILD(ast, node->nd_recv),
+                                    RBOOL(node->nd_next->nd_aid),
+                                    ID2SYM(node->nd_next->nd_vid),
+                                    ID2SYM(node->nd_next->nd_mid),
+                                    NEW_CHILD(ast, node->nd_value));
+      case NODE_OP_ASGN_AND:
+        return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_head), ID2SYM(idANDOP),
+                                    NEW_CHILD(ast, node->nd_value));
+      case NODE_OP_ASGN_OR:
+        return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_head), ID2SYM(idOROP),
+                                    NEW_CHILD(ast, node->nd_value));
+      case NODE_OP_CDECL:
+        return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_head),
+                                    ID2SYM(node->nd_aid),
+                                    NEW_CHILD(ast, node->nd_value));
+      case NODE_CALL:
+      case NODE_OPCALL:
+      case NODE_QCALL:
+        return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_recv),
+                                    ID2SYM(node->nd_mid),
+                                    NEW_CHILD(ast, node->nd_args));
+      case NODE_FCALL:
+        return rb_ary_new_from_args(2, ID2SYM(node->nd_mid),
+                                    NEW_CHILD(ast, node->nd_args));
+      case NODE_VCALL:
+        return rb_ary_new_from_args(1, ID2SYM(node->nd_mid));
+      case NODE_SUPER:
+        return rb_ary_new_from_node_args(ast, 1, node->nd_args);
+      case NODE_ZSUPER:
+        return rb_ary_new_from_node_args(ast, 0);
+      case NODE_LIST:
+      case NODE_VALUES:
+        return dump_array(ast, node);
+      case NODE_ZLIST:
+        return rb_ary_new_from_node_args(ast, 0);
+      case NODE_HASH:
+        return rb_ary_new_from_node_args(ast, 1, node->nd_head);
+      case NODE_YIELD:
+        return rb_ary_new_from_node_args(ast, 1, node->nd_head);
+      case NODE_LVAR:
+      case NODE_DVAR:
+        return rb_ary_new_from_args(1, var_name(node->nd_vid));
+      case NODE_IVAR:
+      case NODE_CONST:
+      case NODE_CVAR:
+      case NODE_GVAR:
+        return rb_ary_new_from_args(1, ID2SYM(node->nd_vid));
+      case NODE_NTH_REF:
+        snprintf(name, sizeof(name), "$%ld", node->nd_nth);
+        return rb_ary_new_from_args(1, ID2SYM(rb_intern(name)));
+      case NODE_BACK_REF:
+        name[0] = '$';
+        name[1] = (char)node->nd_nth;
+        name[2] = '\0';
+        return rb_ary_new_from_args(1, ID2SYM(rb_intern(name)));
+      case NODE_MATCH2:
+        if (node->nd_args) {
+            return rb_ary_new_from_node_args(ast, 3, node->nd_recv, node->nd_value, node->nd_args);
+        }
+        return rb_ary_new_from_node_args(ast, 2, node->nd_recv, node->nd_value);
+      case NODE_MATCH3:
+        return rb_ary_new_from_node_args(ast, 2, node->nd_recv, node->nd_value);
+      case NODE_MATCH:
+      case NODE_LIT:
+      case NODE_STR:
+      case NODE_XSTR:
+        return rb_ary_new_from_args(1, node->nd_lit);
+      case NODE_ONCE:
+        return rb_ary_new_from_node_args(ast, 1, node->nd_body);
+      case NODE_DSTR:
+      case NODE_DXSTR:
+      case NODE_DREGX:
+      case NODE_DSYM:
+        {
+            NODE *n = node->nd_next;
+            VALUE head = Qnil, next = Qnil;
+            if (n) {
+                head = NEW_CHILD(ast, n->nd_head);
+                next = NEW_CHILD(ast, n->nd_next);
+            }
+            return rb_ary_new_from_args(3, node->nd_lit, head, next);
+        }
+      case NODE_EVSTR:
+        return rb_ary_new_from_node_args(ast, 1, node->nd_body);
+      case NODE_ARGSCAT:
+        return rb_ary_new_from_node_args(ast, 2, node->nd_head, node->nd_body);
+      case NODE_ARGSPUSH:
+        return rb_ary_new_from_node_args(ast, 2, node->nd_head, node->nd_body);
+      case NODE_SPLAT:
+        return rb_ary_new_from_node_args(ast, 1, node->nd_head);
+      case NODE_BLOCK_PASS:
+        return rb_ary_new_from_node_args(ast, 2, node->nd_head, node->nd_body);
+      case NODE_DEFN:
+        return rb_ary_new_from_args(2, ID2SYM(node->nd_mid), NEW_CHILD(ast, node->nd_defn));
+      case NODE_DEFS:
+        return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_recv), ID2SYM(node->nd_mid), NEW_CHILD(ast, node->nd_defn));
+      case NODE_ALIAS:
+        return rb_ary_new_from_node_args(ast, 2, node->nd_1st, node->nd_2nd);
+      case NODE_VALIAS:
+        return rb_ary_new_from_args(2, ID2SYM(node->nd_alias), ID2SYM(node->nd_orig));
+      case NODE_UNDEF:
+        return rb_ary_new_from_node_args(ast, 1, node->nd_undef);
+      case NODE_CLASS:
+        return rb_ary_new_from_node_args(ast, 3, node->nd_cpath, node->nd_super, node->nd_body);
+      case NODE_MODULE:
+        return rb_ary_new_from_node_args(ast, 2, node->nd_cpath, node->nd_body);
+      case NODE_SCLASS:
+        return rb_ary_new_from_node_args(ast, 2, node->nd_recv, node->nd_body);
+      case NODE_COLON2:
+        return rb_ary_new_from_args(2, NEW_CHILD(ast, node->nd_head), ID2SYM(node->nd_mid));
+      case NODE_COLON3:
+        return rb_ary_new_from_args(1, ID2SYM(node->nd_mid));
+      case NODE_DOT2:
+      case NODE_DOT3:
+      case NODE_FLIP2:
+      case NODE_FLIP3:
+        return rb_ary_new_from_node_args(ast, 2, node->nd_beg, node->nd_end);
+      case NODE_SELF:
+        return rb_ary_new_from_node_args(ast, 0);
+      case NODE_NIL:
+        return rb_ary_new_from_node_args(ast, 0);
+      case NODE_TRUE:
+        return rb_ary_new_from_node_args(ast, 0);
+      case NODE_FALSE:
+        return rb_ary_new_from_node_args(ast, 0);
+      case NODE_ERRINFO:
+        return rb_ary_new_from_node_args(ast, 0);
+      case NODE_DEFINED:
+        return rb_ary_new_from_node_args(ast, 1, node->nd_head);
+      case NODE_POSTEXE:
+        return rb_ary_new_from_node_args(ast, 1, node->nd_body);
+      case NODE_ATTRASGN:
+        return rb_ary_new_from_args(3, NEW_CHILD(ast, node->nd_recv), ID2SYM(node->nd_mid), NEW_CHILD(ast, node->nd_args));
+      case NODE_LAMBDA:
+        return rb_ary_new_from_node_args(ast, 1, node->nd_body);
+      case NODE_OPT_ARG:
+        return rb_ary_new_from_node_args(ast, 2, node->nd_body, node->nd_next);
+      case NODE_KW_ARG:
+        return rb_ary_new_from_node_args(ast, 2, node->nd_body, node->nd_next);
+      case NODE_POSTARG:
+        if (NODE_NAMED_REST_P(node->nd_1st)) {
+            return rb_ary_new_from_node_args(ast, 2, node->nd_1st, node->nd_2nd);
+        }
+        return rb_ary_new_from_args(2, no_name_rest(),
+                                    NEW_CHILD(ast, node->nd_2nd));
+      case NODE_ARGS:
+        {
+            struct rb_args_info *ainfo = node->nd_ainfo;
+            return rb_ary_new_from_args(10,
+                                        INT2NUM(ainfo->pre_args_num),
+                                        NEW_CHILD(ast, ainfo->pre_init),
+                                        NEW_CHILD(ast, ainfo->opt_args),
+                                        var_name(ainfo->first_post_arg),
+                                        INT2NUM(ainfo->post_args_num),
+                                        NEW_CHILD(ast, ainfo->post_init),
+                                        (ainfo->rest_arg == NODE_SPECIAL_EXCESSIVE_COMMA
+                                            ? ID2SYM(rb_intern("NODE_SPECIAL_EXCESSIVE_COMMA"))
+                                            : var_name(ainfo->rest_arg)),
+                                        (ainfo->no_kwarg ? Qfalse : NEW_CHILD(ast, ainfo->kw_args)),
+                                        (ainfo->no_kwarg ? Qfalse : NEW_CHILD(ast, ainfo->kw_rest_arg)),
+                                        var_name(ainfo->block_arg));
+        }
+      case NODE_SCOPE:
+        {
+            rb_ast_id_table_t *tbl = node->nd_tbl;
+            int i, size = tbl ? tbl->size : 0;
+            VALUE locals = rb_ary_new_capa(size);
+            for (i = 0; i < size; i++) {
+                rb_ary_push(locals, var_name(tbl->ids[i]));
+            }
+            return rb_ary_new_from_args(3, locals, NEW_CHILD(ast, node->nd_args), NEW_CHILD(ast, node->nd_body));
+        }
+      case NODE_ARYPTN:
+        {
+            struct rb_ary_pattern_info *apinfo = node->nd_apinfo;
+            VALUE rest = rest_arg(ast, apinfo->rest_arg);
+            return rb_ary_new_from_args(4,
+                                        NEW_CHILD(ast, node->nd_pconst),
+                                        NEW_CHILD(ast, apinfo->pre_args),
+                                        rest,
+                                        NEW_CHILD(ast, apinfo->post_args));
+        }
+      case NODE_FNDPTN:
+        {
+            struct rb_fnd_pattern_info *fpinfo = node->nd_fpinfo;
+            VALUE pre_rest = rest_arg(ast, fpinfo->pre_rest_arg);
+            VALUE post_rest = rest_arg(ast, fpinfo->post_rest_arg);
+            return rb_ary_new_from_args(4,
+                                        NEW_CHILD(ast, node->nd_pconst),
+                                        pre_rest,
+                                        NEW_CHILD(ast, fpinfo->args),
+                                        post_rest);
+        }
+      case NODE_HSHPTN:
+        {
+            VALUE kwrest = node->nd_pkwrestarg == NODE_SPECIAL_NO_REST_KEYWORD ? ID2SYM(rb_intern("NODE_SPECIAL_NO_REST_KEYWORD")) :
+                                                                                 NEW_CHILD(ast, node->nd_pkwrestarg);
+
+            return rb_ary_new_from_args(3,
+                                        NEW_CHILD(ast, node->nd_pconst),
+                                        NEW_CHILD(ast, node->nd_pkwargs),
+                                        kwrest);
+        }
+      case NODE_ERROR:
+        return rb_ary_new_from_node_args(ast, 0);
+      case NODE_ARGS_AUX:
+      case NODE_LAST:
+        break;
+    }
+
+    rb_bug("node_children: unknown node: %s", ruby_node_name(type));
+}
+
+static VALUE
+ast_node_children(rb_execution_context_t *ec, VALUE self)
+{
+    struct ASTNodeData *data;
+    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);
+
+    return node_children(data->ast, data->node);
+}
+
+static VALUE
+ast_node_first_lineno(rb_execution_context_t *ec, VALUE self)
+{
+    struct ASTNodeData *data;
+    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);
+
+    return INT2NUM(nd_first_lineno(data->node));
+}
+
+static VALUE
+ast_node_first_column(rb_execution_context_t *ec, VALUE self)
+{
+    struct ASTNodeData *data;
+    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);
+
+    return INT2NUM(nd_first_column(data->node));
+}
+
+static VALUE
+ast_node_last_lineno(rb_execution_context_t *ec, VALUE self)
+{
+    struct ASTNodeData *data;
+    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);
+
+    return INT2NUM(nd_last_lineno(data->node));
+}
+
+static VALUE
+ast_node_last_column(rb_execution_context_t *ec, VALUE self)
+{
+    struct ASTNodeData *data;
+    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);
+
+    return INT2NUM(nd_last_column(data->node));
+}
+
+static VALUE
+ast_node_all_tokens(rb_execution_context_t *ec, VALUE self)
+{
+    struct ASTNodeData *data;
+    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);
+
+    return rb_ast_tokens(data->ast);
+}
+
+static VALUE
+ast_node_inspect(rb_execution_context_t *ec, VALUE self)
+{
+    VALUE str;
+    VALUE cname;
+    struct ASTNodeData *data;
+    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);
+
+    cname = rb_class_path(rb_obj_class(self));
+    str = rb_str_new2("#<");
+
+    rb_str_append(str, cname);
+    rb_str_catf(str, ":%s@%d:%d-%d:%d>",
+                node_type_to_str(data->node),
+                nd_first_lineno(data->node), nd_first_column(data->node),
+                nd_last_lineno(data->node), nd_last_column(data->node));
+
+    return str;
+}
+
+static VALUE
+ast_node_script_lines(rb_execution_context_t *ec, VALUE self)
+{
+    struct ASTNodeData *data;
+    TypedData_Get_Struct(self, struct ASTNodeData, &rb_node_type, data);
+    VALUE ret = data->ast->body.script_lines;
+    if (!RB_TYPE_P(ret, T_ARRAY)) return Qnil;
+    return ret;
+}
+
+#include "ast.rbinc"
+
+void
+Init_ast(void)
+{
+    rb_mAST = rb_define_module_under(rb_cRubyVM, "AbstractSyntaxTree");
+    rb_cNode = rb_define_class_under(rb_mAST, "Node", rb_cObject);
+    rb_undef_alloc_func(rb_cNode);
+}
diff --git a/ast.rb b/ast.rb
new file mode 100644
index 0000000000..f3f72c747f
--- /dev/null
+++ b/ast.rb
@@ -0,0 +1,276 @@
+# for ast.c
+
+# AbstractSyntaxTree provides methods to parse Ruby code into
+# abstract syntax trees. The nodes in the tree
+# are instances of RubyVM::AbstractSyntaxTree::Node.
+#
+# This module is MRI specific as it exposes implementation details
+# of the MRI abstract syntax tree.
+#
+# This module is experimental and its API is not stable, therefore it might
+# change without notice. As examples, the order of children nodes is not
+# guaranteed, the number of children nodes might change, there is no way to
+# access children nodes by name, etc.
+#
+# If you are looking for a stable API or an API working under multiple Ruby
+# implementations, consider using the _parser_ gem or Ripper. If you would
+# like to make RubyVM::AbstractSyntaxTree stable, please join the discussion
+# at https://bugs.ruby-lang.org/issues/14844.
+#
+module RubyVM::AbstractSyntaxTree
+
+  #  call-seq:
+  #     RubyVM::AbstractSyntaxTree.parse(string, keep_script_lines: false, error_tolerant: false, keep_tokens: false) -> RubyVM::AbstractSyntaxTree::Node
+  #
+  #  Parses the given _string_ into an abstract syntax tree,
+  #  returning the root node of that tree.
+  #
+  #    RubyVM::AbstractSyntaxTree.parse("x = 1 + 2")
+  #    # => #<RubyVM::AbstractSyntaxTree::Node:SCOPE@1:0-1:9>
+  #
+  #  If <tt>keep_script_lines: true</tt> option is provided, the text of the parsed
+  #  source is associated with nodes and is available via Node#script_lines.
+  #
+  #  If <tt>keep_tokens: true</tt> option is provided, Node#tokens are populated.
+  #
+  #  SyntaxError is raised if the given _string_ is invalid syntax. To overwrite this
+  #  behavior, <tt>error_tolerant: true</tt> can be provided. In this case, the parser
+  #  will produce a tree where expressions with syntax errors would be represented by
+  #  Node with <tt>type=:ERROR</tt>.
+  #
+  #     root = RubyVM::AbstractSyntaxTree.parse("x = 1; p(x; y=2")
+  #     # <internal:ast>:33:in `parse': syntax error, unexpected ';', expecting ')' (SyntaxError)
+  #     # x = 1; p(x; y=2
+  #     #           ^
+  #
+  #     root = RubyVM::AbstractSyntaxTree.parse("x = 1; p(x; y=2", error_tolerant: true)
+  #     # (SCOPE@1:0-1:15
+  #     #  tbl: [:x, :y]
+  #     #  args: nil
+  #     #  body: (BLOCK@1:0-1:15 (LASGN@1:0-1:5 :x (LIT@1:4-1:5 1)) (ERROR@1:7-1:11) (LASGN@1:12-1:15 :y (LIT@1:14-1:15 2))))
+  #     root.children.last.children
+  #     # [(LASGN@1:0-1:5 :x (LIT@1:4-1:5 1)),
+  #     #  (ERROR@1:7-1:11),
+  #     #  (LASGN@1:12-1:15 :y (LIT@1:14-1:15 2))]
+  #
+  #  Note that parsing continues even after the errored expresion.
+  #
+  def self.parse string, keep_script_lines: false, error_tolerant: false, keep_tokens: false
+    Primitive.ast_s_parse string, keep_script_lines, error_tolerant, keep_tokens
+  end
+
+  #  call-seq:
+  #     RubyVM::AbstractSyntaxTree.parse_file(pathname, keep_script_lines: false, error_tolerant: false, keep_tokens: false) -> RubyVM::AbstractSyntaxTree::Node
+  #
+  #   Reads the file from _pathname_, then parses it like ::parse,
+  #   returning the root node of the abstract syntax tree.
+  #
+  #   SyntaxError is raised if _pathname_'s contents are not
+  #   valid Ruby syntax.
+  #
+  #     RubyVM::AbstractSyntaxTree.parse_file("my-app/app.rb")
+  #     # => #<RubyVM::AbstractSyntaxTree::Node:SCOPE@1:0-31:3>
+  #
+  #   See ::parse for explanation of keyword argument meaning and usage.
+  def self.parse_file pathname, keep_script_lines: false, error_tolerant: false, keep_tokens: false
+    Primitive.ast_s_parse_file pathname, keep_script_lines, error_tolerant, keep_tokens
+  end
+
+  #  call-seq:
+  #     RubyVM::AbstractSyntaxTree.of(proc, keep_script_lines: false, error_tolerant: false, keep_tokens: false)   -> RubyVM::AbstractSyntaxTree::Node
+  #     RubyVM::AbstractSyntaxTree.of(method, keep_script_lines: false, error_tolerant: false, keep_tokens: false) -> RubyVM::AbstractSyntaxTree::Node
+  #
+  #   Returns AST nodes of the given _proc_ or _method_.
+  #
+  #     RubyVM::AbstractSyntaxTree.of(proc {1 + 2})
+  #     # => #<RubyVM::AbstractSyntaxTree::Node:SCOPE@1:35-1:42>
+  #
+  #     def hello
+  #       puts "hello, world"
+  #     end
+  #
+  #     RubyVM::AbstractSyntaxTree.of(method(:hello))
+  #     # => #<RubyVM::AbstractSyntaxTree::Node:SCOPE@1:0-3:3>
+  #
+  #   See ::parse for explanation of keyword argument meaning and usage.
+  def self.of body, keep_script_lines: false, error_tolerant: false, keep_tokens: false
+    Primitive.ast_s_of body, keep_script_lines, error_tolerant, keep_tokens
+  end
+
+  #  call-seq:
+  #     RubyVM::AbstractSyntaxTree.node_id_for_backtrace_location(backtrace_location)   -> integer
+  #
+  #   Returns the node id for the given backtrace location.
+  #
+  #     begin
+  #       raise
+  #     rescue =>  e
+  #       loc = e.backtrace_locations.first
+  #       RubyVM::AbstractSyntaxTree.node_id_for_backtrace_location(loc)
+  #     end # => 0
+  def self.node_id_for_backtrace_location backtrace_location
+    Primitive.node_id_for_backtrace_location backtrace_location
+  end
+
+  # RubyVM::AbstractSyntaxTree::Node instances are created by parse methods in
+  # RubyVM::AbstractSyntaxTree.
+  #
+  # This class is MRI specific.
+  #
+  class Node
+
+    #  call-seq:
+    #     node.type -> symbol
+    #
+    #  Returns the type of this node as a symbol.
+    #
+    #    root = RubyVM::AbstractSyntaxTree.parse("x = 1 + 2")
+    #    root.type # => :SCOPE
+    #    lasgn = root.children[2]
+    #    lasgn.type # => :LASGN
+    #    call = lasgn.children[1]
+    #    call.type # => :OPCALL
+    def type
+      Primitive.ast_node_type
+    end
+
+    #  call-seq:
+    #     node.first_lineno -> integer
+    #
+    #  The line number in the source code where this AST's text began.
+    def first_lineno
+      Primitive.ast_node_first_lineno
+    end
+
+    #  call-seq:
+    #     node.first_column -> integer
+    #
+    #  The column number in the source code where this AST's text began.
+    def first_column
+      Primitive.ast_node_first_column
+    end
+
+    #  call-seq:
+    #     node.last_lineno -> integer
+    #
+    #  The line number in the source code where this AST's text ended.
+    def last_lineno
+      Primitive.ast_node_last_lineno
+    end
+
+    #  call-seq:
+    #     node.last_column -> integer
+    #
+    #  The column number in the source code where this AST's text ended.
+    def last_column
+      Primitive.ast_node_last_column
+    end
+
+    #  call-seq:
+    #     node.tokens -> array
+    #
+    #  Returns tokens corresponding to the location of the node.
+    #  Returns +nil+ if +keep_tokens+ is not enabled when #parse method is called.
+    #
+    #    root = RubyVM::AbstractSyntaxTree.parse("x = 1 + 2", keep_tokens: true)
+    #    root.tokens # => [[0, :tIDENTIFIER, "x", [1, 0, 1, 1]], [1, :tSP, " ", [1, 1, 1, 2]], ...]
+    #    root.tokens.map{_1[2]}.join # => "x = 1 + 2"
+    #
+    #  Token is an array of:
+    #
+    #  - id
+    #  - token type
+    #  - source code text
+    #  - location [ first_lineno, first_column, last_lineno, last_column ]
+    def tokens
+      return nil unless all_tokens
+
+      all_tokens.each_with_object([]) do |token, a|
+        loc = token.last
+        if ([first_lineno, first_column] <=> [loc[0], loc[1]]) <= 0 &&
+           ([last_lineno, last_column]   <=> [loc[2], loc[3]]) >= 0
+           a << token
+        end
+      end
+    end
+
+    #  call-seq:
+    #     node.all_tokens -> array
+    #
+    #  Returns all tokens for the input script regardless the receiver node.
+    #  Returns +nil+ if +keep_tokens+ is not enabled when #parse method is called.
+    #
+    #    root = RubyVM::AbstractSyntaxTree.parse("x = 1 + 2", keep_tokens: true)
+    #    root.all_tokens # => [[0, :tIDENTIFIER, "x", [1, 0, 1, 1]], [1, :tSP, " ", [1, 1, 1, 2]], ...]
+    #    root.children[-1].all_tokens # => [[0, :tIDENTIFIER, "x", [1, 0, 1, 1]], [1, :tSP, " ", [1, 1, 1, 2]], ...]
+    def all_tokens
+      Primitive.ast_node_all_tokens
+    end
+
+    #  call-seq:
+    #     node.children -> array
+    #
+    #  Returns AST nodes under this one.  Each kind of node
+    #  has different children, depending on what kind of node it is.
+    #
+    #  The returned array may contain other nodes or <code>nil</code>.
+    def children
+      Primitive.ast_node_children
+    end
+
+    #  call-seq:
+    #     node.inspect -> string
+    #
+    #  Returns debugging information about this node as a string.
+    def inspect
+      Primitive.ast_node_inspect
+    end
+
+    #  call-seq:
+    #     node.node_id -> integer
+    #
+    #  Returns an internal node_id number.
+    #  Note that this is an API for ruby internal use, debugging,
+    #  and research. Do not use this for any other purpose.
+    #  The compatibility is not guaranteed.
+    def node_id
+      Primitive.ast_node_node_id
+    end
+
+    #  call-seq:
+    #     node.script_lines -> array
+    #
+    #  Returns the original source code as an array of lines.
+    #
+    #  Note that this is an API for ruby internal use, debugging,
+    #  and research. Do not use this for any other purpose.
+    #  The compatibility is not guaranteed.
+    def script_lines
+      Primitive.ast_node_script_lines
+    end
+
+    #  call-seq:
+    #     node.source -> string
+    #
+    #  Returns the code fragment that corresponds to this AST.
+    #
+    #  Note that this is an API for ruby internal use, debugging,
+    #  and research. Do not use this for any other purpose.
+    #  The compatibility is not guaranteed.
+    #
+    #  Also note that this API may return an incomplete code fragment
+    #  that does not parse; for example, a here document following
+    #  an expression may be dropped.
+    def source
+      lines = script_lines
+      if lines
+        lines = lines[first_lineno - 1 .. last_lineno - 1]
+        lines[-1] = lines[-1][0...last_column]
+        lines[0] = lines[0][first_column..-1]
+        lines.join
+      else
+        nil
+      end
+    end
+  end
+end
diff --git a/autogen.sh b/autogen.sh
new file mode 100755
index 0000000000..f8cdf3c0c1
--- /dev/null
+++ b/autogen.sh
@@ -0,0 +1,17 @@
+#!/bin/sh
+
+PWD=
+case "$0" in
+*/*) srcdir=`dirname $0`;;
+*) srcdir="";;
+esac
+
+symlink='--install --symlink'
+case " $* " in
+    *" -i "*|*" --install "*)
+        # reset to copy missing standard auxiliary files, instead of symlinks
+        symlink=
+        ;;
+esac
+
+exec ${AUTORECONF:-autoreconf} ${symlink} "$@" ${srcdir:+"$srcdir"}
diff --git a/basictest/runner.rb b/basictest/runner.rb
new file mode 100755
index 0000000000..0f398e7acc
--- /dev/null
+++ b/basictest/runner.rb
@@ -0,0 +1,33 @@
+#! ./miniruby
+
+exit if defined?(CROSS_COMPILING) and CROSS_COMPILING
+ruby = ENV["RUBY"]
+unless ruby
+  load './rbconfig.rb'
+  ruby = "./#{RbConfig::CONFIG['ruby_install_name']}#{RbConfig::CONFIG['EXEEXT']}"
+end
+unless File.exist? ruby
+  print "#{ruby} is not found.\n"
+  print "Try `make' first, then `make test', please.\n"
+  exit false
+end
+ARGV[0] and opt = ARGV[0][/\A--run-opt=(.*)/, 1] and ARGV.shift
+
+$stderr.reopen($stdout)
+error = ''
+
+srcdir = File.expand_path('..', File.dirname(__FILE__))
+if env = ENV["RUBYOPT"]
+  ENV["RUBYOPT"] = env + " -W1"
+end
+`#{ruby} #{opt} -W1 #{srcdir}/basictest/test.rb #{ARGV.join(' ')}`.each_line do |line|
+  if line =~ /^end of test/
+    print "\ntest succeeded\n"
+    exit true
+  end
+  error << line if %r:^(basictest/test.rb|not): =~ line
+end
+puts
+print error
+print "test failed\n"
+exit false
diff --git a/basictest/test.rb b/basictest/test.rb
new file mode 100755
index 0000000000..95875b52a6
--- /dev/null
+++ b/basictest/test.rb
@@ -0,0 +1,2367 @@
+#! /usr/bin/env ruby
+# -*- coding: us-ascii -*-
+
+$testnum=0
+$ntest=0
+$failed = 0
+class Progress
+  def initialize
+    @color = nil
+    @tty = nil
+    @quiet = nil
+    @verbose = nil
+    ARGV.each do |arg|
+      case arg
+      when /\A--color(?:=(?:always|(auto)|(never)|(.*)))?\z/
+        warn "unknown --color argument: #$3" if $3
+        @color = $1 ? nil : !$2
+      when /\A--tty(=(?:yes|(no)|(.*)))?\z/
+        warn "unknown --tty argument: #$3" if $3
+        @tty = !$1 || !$2
+        true
+      when /\A-(q|-quiet)\z/
+        @quiet = true
+      when /\A-(v|-verbose)\z/
+        @verbose = true
+      end
+    end
+    @tty = STDERR.tty? && !STDOUT.tty? && /dumb/ !~ ENV["TERM"] if @tty.nil?
+    @eol = @tty && !@verbose ? "\r\e[K\r" : "\n"
+    case @color
+    when nil
+      @color = @tty
+    end
+    if @color
+      # dircolors-like style
+      colors = (colors = ENV['TEST_COLORS']) ? Hash[colors.scan(/(\w+)=([^:\n]*)/)] : {}
+      begin
+        File.read(File.join(__dir__, "../tool/colors")).scan(/(\w+)=([^:\n]*)/) do |n, c|
+          colors[n] ||= c
+        end
+      rescue
+      end
+      @passed = "\e[;#{colors["pass"] || "32"}m"
+      @failed = "\e[;#{colors["fail"] || "31"}m"
+      @reset = "\e[m"
+    else
+      @passed = @failed = @reset = ""
+    end
+    extend(Rotator) if @tty
+  end
+
+  def passed_string
+    "."
+  end
+  def failed_string
+    "#{@failed}F#{@reset}"
+  end
+  def init_string
+  end
+  def finish_string
+    if @quiet
+      @eol
+    else
+      "#{@passed}#{@ok ? 'OK' : ''} #{$testnum}#{@reset}#{@eol}"
+    end
+  end
+  def pass
+    STDERR.print passed_string
+  end
+  def fail
+    @ok = false
+    STDERR.print failed_string
+  end
+  def init
+    @ok = true
+    STDERR.print init_string
+  end
+  def finish
+    STDERR.print finish_string
+  end
+
+  module Rotator
+    ROTATOR = %w[- \\ | /]
+    BS = "\b" * ROTATOR[0].size
+    def passed_string
+      "#{BS}#{ROTATOR[(@count += 1) % ROTATOR.size]}"
+    end
+    def failed_string
+      "#{BS}#{super}#{ROTATOR[@count % ROTATOR.size]}"
+    end
+    def init_string
+      @count = 0
+      " "
+    end
+    def finish_string
+      s = "#{BS}#{' ' * BS.size}#{BS}#{super}"
+      s.gsub!(/\n/, "\r\e[2K\r") if @quiet
+      s
+    end
+  end
+end
+PROGRESS = Progress.new
+
+def test_check(what)
+  unless $ntest.zero?
+    PROGRESS.finish
+  end
+  STDERR.print "#{$0}:#{what} "
+  PROGRESS.init
+  $what = what
+  $testnum = 0
+end
+
+def test_ok(cond,n=1)
+  $testnum+=1
+  $ntest+=1
+  where = (st = caller(n)) ? st[0] : "caller error! (n=#{n}, trace=#{caller(0).join(', ')}"
+  if cond
+    PROGRESS.pass
+    printf "ok %d (%s)\n", $testnum, where
+  else
+    PROGRESS.fail
+    printf "not ok %s %d -- %s\n", $what, $testnum, where
+    $failed+=1
+  end
+  STDOUT.flush
+  STDERR.flush
+end
+
+# make sure conditional operators work
+
+test_check "assignment"
+
+a=[]; a[0] ||= "bar";
+test_ok(a[0] == "bar")
+h={}; h["foo"] ||= "bar";
+test_ok(h["foo"] == "bar")
+
+aa = 5
+aa ||= 25
+test_ok(aa == 5)
+bb ||= 25
+test_ok(bb == 25)
+cc &&=33
+test_ok(cc == nil)
+cc = 5
+cc &&=44
+test_ok(cc == 44)
+
+a = nil; test_ok(a == nil)
+a = 1; test_ok(a == 1)
+a = []; test_ok(a == [])
+a = [1]; test_ok(a == [1])
+a = [nil]; test_ok(a == [nil])
+a = [[]]; test_ok(a == [[]])
+a = [1,2]; test_ok(a == [1,2])
+a = [*[]]; test_ok(a == [])
+a = [*[1]]; test_ok(a == [1])
+a = [*[1,2]]; test_ok(a == [1,2])
+
+a = *[]; test_ok(a == [])
+a = *[1]; test_ok(a == [1])
+a = *[nil]; test_ok(a == [nil])
+a = *[[]]; test_ok(a == [[]])
+a = *[1,2]; test_ok(a == [1,2])
+a = *[*[]]; test_ok(a == [])
+a = *[*[1]]; test_ok(a == [1])
+a = *[*[1,2]]; test_ok(a == [1,2])
+
+a, = nil; test_ok(a == nil)
+a, = 1; test_ok(a == 1)
+a, = []; test_ok(a == nil)
+a, = [1]; test_ok(a == 1)
+a, = [nil]; test_ok(a == nil)
+a, = [[]]; test_ok(a == [])
+a, = 1,2; test_ok(a == 1)
+a, = [1,2]; test_ok(a == 1)
+a, = [*[]]; test_ok(a == nil)
+a, = [*[1]]; test_ok(a == 1)
+a, = *[1,2]; test_ok(a == 1)
+a, = [*[1,2]]; test_ok(a == 1)
+
+a, = *[]; test_ok(a == nil)
+a, = *[1]; test_ok(a == 1)
+a, = *[nil]; test_ok(a == nil)
+a, = *[[]]; test_ok(a == [])
+a, = *[1,2]; test_ok(a == 1)
+a, = *[*[]]; test_ok(a == nil)
+a, = *[*[1]]; test_ok(a == 1)
+a, = *[*[1,2]]; test_ok(a == 1)
+
+*a = nil; test_ok(a == [nil])
+*a = 1; test_ok(a == [1])
+*a = []; test_ok(a == [])
+*a = [1]; test_ok(a == [1])
+*a = [nil]; test_ok(a == [nil])
+*a = [[]]; test_ok(a == [[]])
+*a = [1,2]; test_ok(a == [1,2])
+*a = [*[]]; test_ok(a == [])
+*a = [*[1]]; test_ok(a == [1])
+*a = [*[1,2]]; test_ok(a == [1,2])
+
+*a = *[]; test_ok(a == [])
+*a = *[1]; test_ok(a == [1])
+*a = *[nil]; test_ok(a == [nil])
+*a = *[[]]; test_ok(a == [[]])
+*a = *[1,2]; test_ok(a == [1,2])
+*a = *[*[]]; test_ok(a == [])
+*a = *[*[1]]; test_ok(a == [1])
+*a = *[*[1,2]]; test_ok(a == [1,2])
+
+a,b,*c = nil; test_ok([a,b,c] == [nil,nil,[]])
+a,b,*c = 1; test_ok([a,b,c] == [1,nil,[]])
+a,b,*c = []; test_ok([a,b,c] == [nil,nil,[]])
+a,b,*c = [1]; test_ok([a,b,c] == [1,nil,[]])
+a,b,*c = [nil]; test_ok([a,b,c] == [nil,nil,[]])
+a,b,*c = [[]]; test_ok([a,b,c] == [[],nil,[]])
+a,b,*c = [1,2]; test_ok([a,b,c] == [1,2,[]])
+a,b,*c = [*[]]; test_ok([a,b,c] == [nil,nil,[]])
+a,b,*c = [*[1]]; test_ok([a,b,c] == [1,nil,[]])
+a,b,*c = [*[1,2]]; test_ok([a,b,c] == [1,2,[]])
+
+a,b,*c = *[]; test_ok([a,b,c] == [nil,nil,[]])
+a,b,*c = *[1]; test_ok([a,b,c] == [1,nil,[]])
+a,b,*c = *[nil]; test_ok([a,b,c] == [nil,nil,[]])
+a,b,*c = *[[]]; test_ok([a,b,c] == [[],nil,[]])
+a,b,*c = *[1,2]; test_ok([a,b,c] == [1,2,[]])
+a,b,*c = *[*[]]; test_ok([a,b,c] == [nil,nil,[]])
+a,b,*c = *[*[1]]; test_ok([a,b,c] == [1,nil,[]])
+a,b,*c = *[*[1,2]]; test_ok([a,b,c] == [1,2,[]])
+
+def f; yield nil; end; f {|a| test_ok(a == nil)}
+def f; yield 1; end; f {|a| test_ok(a == 1)}
+def f; yield []; end; f {|a| test_ok(a == [])}
+def f; yield [1]; end; f {|a| test_ok(a == [1])}
+def f; yield [nil]; end; f {|a| test_ok(a == [nil])}
+def f; yield [[]]; end; f {|a| test_ok(a == [[]])}
+def f; yield [*[]]; end; f {|a| test_ok(a == [])}
+def f; yield [*[1]]; end; f {|a| test_ok(a == [1])}
+def f; yield [*[1,2]]; end; f {|a| test_ok(a == [1,2])}
+def f; yield *[]; end; f {|a| test_ok(a == nil)}
+def f; yield *[1]; end; f {|a| test_ok(a == 1)}
+def f; yield *[nil]; end; f {|a| test_ok(a == nil)}
+def f; yield *[[]]; end; f {|a| test_ok(a == [])}
+def f; yield *[*[]]; end; f {|a| test_ok(a == nil)}
+def f; yield *[*[1]]; end; f {|a| test_ok(a == 1)}
+def f; yield *[*[1,2]]; end; f {|a| test_ok(a == 1)}
+
+def f; yield; end; f {|a,| test_ok(a == nil)}
+def f; yield nil; end; f {|a,| test_ok(a == nil)}
+def f; yield 1; end; f {|a,| test_ok(a == 1)}
+def f; yield []; end; f {|a,| test_ok(a == nil)}
+def f; yield [1]; end; f {|a,| test_ok(a == 1)}
+def f; yield [nil]; end; f {|a,| test_ok(a == nil)}
+def f; yield [[]]; end; f {|a,| test_ok(a == [])}
+def f; yield [*[]]; end; f {|a,| test_ok(a == nil)}
+def f; yield [*[1]]; end; f {|a,| test_ok(a == 1)}
+def f; yield [*[1,2]]; end; f {|a,| test_ok(a == 1)}
+
+def f; yield *[]; end; f {|a,| test_ok(a == nil)}
+def f; yield *[1]; end; f {|a,| test_ok(a == 1)}
+def f; yield *[nil]; end; f {|a,| test_ok(a == nil)}
+def f; yield *[[]]; end; f {|a,| test_ok(a == nil)}
+def f; yield *[*[]]; end; f {|a,| test_ok(a == nil)}
+def f; yield *[*[1]]; end; f {|a,| test_ok(a == 1)}
+def f; yield *[*[1,2]]; end; f {|a,| test_ok(a == 1)}
+
+def f; yield; end; f {|*a| test_ok(a == [])}
+def f; yield nil; end; f {|*a| test_ok(a == [nil])}
+def f; yield 1; end; f {|*a| test_ok(a == [1])}
+def f; yield []; end; f {|*a| test_ok(a == [[]])}
+def f; yield [1]; end; f {|*a| test_ok(a == [[1]])}
+def f; yield [nil]; end; f {|*a| test_ok(a == [[nil]])}
+def f; yield [[]]; end; f {|*a| test_ok(a == [[[]]])}
+def f; yield [1,2]; end; f {|*a| test_ok(a == [[1,2]])}
+def f; yield [*[]]; end; f {|*a| test_ok(a == [[]])}
+def f; yield [*[1]]; end; f {|*a| test_ok(a == [[1]])}
+def f; yield [*[1,2]]; end; f {|*a| test_ok(a == [[1,2]])}
+
+def f; yield *[]; end; f {|*a| test_ok(a == [])}
+def f; yield *[1]; end; f {|*a| test_ok(a == [1])}
+def f; yield *[nil]; end; f {|*a| test_ok(a == [nil])}
+def f; yield *[[]]; end; f {|*a| test_ok(a == [[]])}
+def f; yield *[*[]]; end; f {|*a| test_ok(a == [])}
+def f; yield *[*[1]]; end; f {|*a| test_ok(a == [1])}
+def f; yield *[*[1,2]]; end; f {|*a| test_ok(a == [1,2])}
+
+def f; yield; end; f {|a,b,*c| test_ok([a,b,c] == [nil,nil,[]])}
+def f; yield nil; end; f {|a,b,*c| test_ok([a,b,c] == [nil,nil,[]])}
+def f; yield 1; end; f {|a,b,*c| test_ok([a,b,c] == [1,nil,[]])}
+def f; yield []; end; f {|a,b,*c| test_ok([a,b,c] == [nil,nil,[]])}
+def f; yield [1]; end; f {|a,b,*c| test_ok([a,b,c] == [1,nil,[]])}
+def f; yield [nil]; end; f {|a,b,*c| test_ok([a,b,c] == [nil,nil,[]])}
+def f; yield [[]]; end; f {|a,b,*c| test_ok([a,b,c] == [[],nil,[]])}
+def f; yield [*[]]; end; f {|a,b,*c| test_ok([a,b,c] == [nil,nil,[]])}
+def f; yield [*[1]]; end; f {|a,b,*c| test_ok([a,b,c] == [1,nil,[]])}
+def f; yield [*[1,2]]; end; f {|a,b,*c| test_ok([a,b,c] == [1,2,[]])}
+
+def f; yield *[]; end; f {|a,b,*c| test_ok([a,b,c] == [nil,nil,[]])}
+def f; yield *[1]; end; f {|a,b,*c| test_ok([a,b,c] == [1,nil,[]])}
+def f; yield *[nil]; end; f {|a,b,*c| test_ok([a,b,c] == [nil,nil,[]])}
+def f; yield *[[]]; end; f {|a,b,*c| test_ok([a,b,c] == [nil,nil,[]])}
+def f; yield *[*[]]; end; f {|a,b,*c| test_ok([a,b,c] == [nil,nil,[]])}
+def f; yield *[*[1]]; end; f {|a,b,*c| test_ok([a,b,c] == [1,nil,[]])}
+def f; yield *[*[1,2]]; end; f {|a,b,*c| test_ok([a,b,c] == [1,2,[]])}
+
+def r; return; end; a = r(); test_ok(a == nil)
+def r; return nil; end; a = r(); test_ok(a == nil)
+def r; return 1; end; a = r(); test_ok(a == 1)
+def r; return []; end; a = r(); test_ok(a == [])
+def r; return [1]; end; a = r(); test_ok(a == [1])
+def r; return [nil]; end; a = r(); test_ok(a == [nil])
+def r; return [[]]; end; a = r(); test_ok(a == [[]])
+def r; return [*[]]; end; a = r(); test_ok(a == [])
+def r; return [*[1]]; end; a = r(); test_ok(a == [1])
+def r; return [*[1,2]]; end; a = r(); test_ok(a == [1,2])
+
+def r; return *[]; end; a = r(); test_ok(a == [])
+def r; return *[1]; end; a = r(); test_ok(a == [1])
+def r; return *[nil]; end; a = r(); test_ok(a == [nil])
+def r; return *[[]]; end; a = r(); test_ok(a == [[]])
+def r; return *[*[]]; end; a = r(); test_ok(a == [])
+def r; return *[*[1]]; end; a = r(); test_ok(a == [1])
+def r; return *[*[1,2]]; end; a = r(); test_ok(a == [1,2])
+
+def r; return *[[]]; end; a = *r(); test_ok(a == [[]])
+def r; return *[*[1,2]]; end; a = *r(); test_ok(a == [1,2])
+
+def r; return; end; *a = r(); test_ok(a == [nil])
+def r; return nil; end; *a = r(); test_ok(a == [nil])
+def r; return 1; end; *a = r(); test_ok(a == [1])
+def r; return []; end; *a = r(); test_ok(a == [])
+def r; return [1]; end; *a = r(); test_ok(a == [1])
+def r; return [nil]; end; *a = r(); test_ok(a == [nil])
+def r; return [[]]; end; *a = r(); test_ok(a == [[]])
+def r; return [1,2]; end; *a = r(); test_ok(a == [1,2])
+def r; return [*[]]; end; *a = r(); test_ok(a == [])
+def r; return [*[1]]; end; *a = r(); test_ok(a == [1])
+def r; return [*[1,2]]; end; *a = r(); test_ok(a == [1,2])
+
+def r; return *[]; end; *a = r(); test_ok(a == [])
+def r; return *[1]; end; *a = r(); test_ok(a == [1])
+def r; return *[nil]; end; *a = r(); test_ok(a == [nil])
+def r; return *[[]]; end; *a = r(); test_ok(a == [[]])
+def r; return *[1,2]; end; *a = r(); test_ok(a == [1,2])
+def r; return *[*[]]; end; *a = r(); test_ok(a == [])
+def r; return *[*[1]]; end; *a = r(); test_ok(a == [1])
+def r; return *[*[1,2]]; end; *a = r(); test_ok(a == [1,2])
+
+def r; return *[[]]; end; *a = *r(); test_ok(a == [[]])
+def r; return *[1,2]; end; *a = *r(); test_ok(a == [1,2])
+def r; return *[*[1,2]]; end; *a = *r(); test_ok(a == [1,2])
+
+def r; return; end; a,b,*c = r(); test_ok([a,b,c] == [nil,nil,[]])
+def r; return nil; end; a,b,*c = r(); test_ok([a,b,c] == [nil,nil,[]])
+def r; return 1; end; a,b,*c = r(); test_ok([a,b,c] == [1,nil,[]])
+def r; return []; end; a,b,*c = r(); test_ok([a,b,c] == [nil,nil,[]])
+def r; return [1]; end; a,b,*c = r(); test_ok([a,b,c] == [1,nil,[]])
+def r; return [nil]; end; a,b,*c = r(); test_ok([a,b,c] == [nil,nil,[]])
+def r; return [[]]; end; a,b,*c = r(); test_ok([a,b,c] == [[],nil,[]])
+def r; return [1,2]; end; a,b,*c = r(); test_ok([a,b,c] == [1,2,[]])
+def r; return [*[]]; end; a,b,*c = r(); test_ok([a,b,c] == [nil,nil,[]])
+def r; return [*[1]]; end; a,b,*c = r(); test_ok([a,b,c] == [1,nil,[]])
+def r; return [*[1,2]]; end; a,b,*c = r(); test_ok([a,b,c] == [1,2,[]])
+
+def r; return *[]; end; a,b,*c = r(); test_ok([a,b,c] == [nil,nil,[]])
+def r; return *[1]; end; a,b,*c = r(); test_ok([a,b,c] == [1,nil,[]])
+def r; return *[nil]; end; a,b,*c = r(); test_ok([a,b,c] == [nil,nil,[]])
+def r; return *[[]]; end; a,b,*c = r(); test_ok([a,b,c] == [[],nil,[]])
+def r; return *[1,2]; end; a,b,*c = r(); test_ok([a,b,c] == [1,2,[]])
+def r; return *[*[]]; end; a,b,*c = r(); test_ok([a,b,c] == [nil,nil,[]])
+def r; return *[*[1]]; end; a,b,*c = r(); test_ok([a,b,c] == [1,nil,[]])
+def r; return *[*[1,2]]; end; a,b,*c = r(); test_ok([a,b,c] == [1,2,[]])
+
+f = lambda {|r,| test_ok([] == r)}
+f.call([], *[])
+
+f = lambda {|r,*l| test_ok([] == r); test_ok([1] == l)}
+f.call([], *[1])
+
+f = lambda{|x| x}
+test_ok(f.call(42) == 42)
+test_ok(f.call([42]) == [42])
+test_ok(f.call([[42]]) == [[42]])
+test_ok(f.call([42,55]) == [42,55])
+
+f = lambda{|x,| x}
+test_ok(f.call(42) == 42)
+test_ok(f.call([42]) == [42])
+test_ok(f.call([[42]]) == [[42]])
+test_ok(f.call([42,55]) == [42,55])
+
+f = lambda{|*x| x}
+test_ok(f.call(42) == [42])
+test_ok(f.call([42]) == [[42]])
+test_ok(f.call([[42]]) == [[[42]]])
+test_ok(f.call([42,55]) == [[42,55]])
+test_ok(f.call(42,55) == [42,55])
+
+f = lambda { |a, b=42, *c| [a,b,c] }
+test_ok(f.call(1      ) == [1,42,[  ]] )
+test_ok(f.call(1,43   ) == [1,43,[  ]] )
+test_ok(f.call(1,43,44) == [1,43,[44]] )
+
+f = lambda { |a, b=(a|16), *c, &block| [a,b,c,block&&block[]] }
+test_ok(f.call(8      )     == [8,24,[  ],nil] )
+test_ok(f.call(8,43   )     == [8,43,[  ],nil] )
+test_ok(f.call(8,43,44)     == [8,43,[44],nil] )
+test_ok(f.call(8      ){45} == [8,24,[  ],45 ] )
+test_ok(f.call(8,43   ){45} == [8,43,[  ],45 ] )
+test_ok(f.call(8,43,44){45} == [8,43,[44],45 ] )
+
+f = lambda { |a, b=42, *c, d| [a,b,c,d] }
+test_ok(f.call(1      ,99) == [1,42,[  ],99] )
+test_ok(f.call(1,43   ,99) == [1,43,[  ],99] )
+test_ok(f.call(1,43,44,99) == [1,43,[44],99] )
+
+f = lambda { |a, b=(a|16), &block| [a,b,block&&block[]] }
+test_ok(f.call(8   )     == [8,24,nil] )
+test_ok(f.call(8,43)     == [8,43,nil] )
+test_ok(f.call(8,43)     == [8,43,nil] )
+test_ok(f.call(8   ){45} == [8,24,45 ] )
+test_ok(f.call(8,43){45} == [8,43,45 ] )
+test_ok(f.call(8,43){45} == [8,43,45 ] )
+
+f = lambda { |a, b=42, d| [a,b,d] }
+test_ok(f.call(1   ,99) == [1,42,99] )
+test_ok(f.call(1,43,99) == [1,43,99] )
+test_ok(f.call(1,43,99) == [1,43,99] )
+
+f = lambda { |b=42, *c, &block| [b,c,block&&block[]] }
+test_ok(f.call(     )     == [42,[  ],nil] )
+test_ok(f.call(43   )     == [43,[  ],nil] )
+test_ok(f.call(43,44)     == [43,[44],nil] )
+test_ok(f.call(     ){45} == [42,[  ],45 ] )
+test_ok(f.call(43   ){45} == [43,[  ],45 ] )
+test_ok(f.call(43,44){45} == [43,[44],45 ] )
+
+f = lambda { |b=42, *c, d| [b,c,d] }
+test_ok(f.call(      99) == [42,[  ],99] )
+test_ok(f.call(43   ,99) == [43,[  ],99] )
+test_ok(f.call(43,44,99) == [43,[44],99] )
+
+f = lambda { |b=42, &block| [b,block&&block[]] }
+test_ok(f.call(  )     == [42,nil] )
+test_ok(f.call(43)     == [43,nil] )
+test_ok(f.call(43)     == [43,nil] )
+test_ok(f.call(  ){45} == [42,45 ] )
+test_ok(f.call(43){45} == [43,45 ] )
+test_ok(f.call(43){45} == [43,45 ] )
+
+f = lambda { |b=42, d| [b,d] }
+test_ok(f.call(   99) == [42,99] )
+test_ok(f.call(43,99) == [43,99] )
+test_ok(f.call(43,99) == [43,99] )
+
+
+a,=*[1]
+test_ok(a == 1)
+a,=*[[1]]
+test_ok(a == [1])
+a,=*[[[1]]]
+test_ok(a == [[1]])
+
+x, (y, z) = 1, 2, 3
+test_ok([1,2,nil] == [x,y,z])
+x, (y, z) = 1, [2,3]
+test_ok([1,2,3] == [x,y,z])
+x, (y, z) = 1, [2]
+test_ok([1,2,nil] == [x,y,z])
+
+a = loop do break; end; test_ok(a == nil)
+a = loop do break nil; end; test_ok(a == nil)
+a = loop do break 1; end; test_ok(a == 1)
+a = loop do break []; end; test_ok(a == [])
+a = loop do break [1]; end; test_ok(a == [1])
+a = loop do break [nil]; end; test_ok(a == [nil])
+a = loop do break [[]]; end; test_ok(a == [[]])
+a = loop do break [*[]]; end; test_ok(a == [])
+a = loop do break [*[1]]; end; test_ok(a == [1])
+a = loop do break [*[1,2]]; end; test_ok(a == [1,2])
+
+a = loop do break *[]; end; test_ok(a == [])
+a = loop do break *[1]; end; test_ok(a == [1])
+a = loop do break *[nil]; end; test_ok(a == [nil])
+a = loop do break *[[]]; end; test_ok(a == [[]])
+a = loop do break *[*[]]; end; test_ok(a == [])
+a = loop do break *[*[1]]; end; test_ok(a == [1])
+a = loop do break *[*[1,2]]; end; test_ok(a == [1,2])
+
+*a = loop do break; end; test_ok(a == [nil])
+*a = loop do break nil; end; test_ok(a == [nil])
+*a = loop do break 1; end; test_ok(a == [1])
+*a = loop do break []; end; test_ok(a == [])
+*a = loop do break [1]; end; test_ok(a == [1])
+*a = loop do break [nil]; end; test_ok(a == [nil])
+*a = loop do break [[]]; end; test_ok(a == [[]])
+*a = loop do break [1,2]; end; test_ok(a == [1,2])
+*a = loop do break [*[]]; end; test_ok(a == [])
+*a = loop do break [*[1]]; end; test_ok(a == [1])
+*a = loop do break [*[1,2]]; end; test_ok(a == [1,2])
+
+*a = loop do break *[]; end; test_ok(a == [])
+*a = loop do break *[1]; end; test_ok(a == [1])
+*a = loop do break *[nil]; end; test_ok(a == [nil])
+*a = loop do break *[[]]; end; test_ok(a == [[]])
+*a = loop do break *[1,2]; end; test_ok(a == [1,2])
+*a = loop do break *[*[]]; end; test_ok(a == [])
+*a = loop do break *[*[1]]; end; test_ok(a == [1])
+*a = loop do break *[*[1,2]]; end; test_ok(a == [1,2])
+
+*a = *loop do break *[[]]; end; test_ok(a == [[]])
+*a = *loop do break *[1,2]; end; test_ok(a == [1,2])
+*a = *loop do break *[*[1,2]]; end; test_ok(a == [1,2])
+
+a,b,*c = loop do break; end; test_ok([a,b,c] == [nil,nil,[]])
+a,b,*c = loop do break nil; end; test_ok([a,b,c] == [nil,nil,[]])
+a,b,*c = loop do break 1; end; test_ok([a,b,c] == [1,nil,[]])
+a,b,*c = loop do break []; end; test_ok([a,b,c] == [nil,nil,[]])
+a,b,*c = loop do break [1]; end; test_ok([a,b,c] == [1,nil,[]])
+a,b,*c = loop do break [nil]; end; test_ok([a,b,c] == [nil,nil,[]])
+a,b,*c = loop do break [[]]; end; test_ok([a,b,c] == [[],nil,[]])
+a,b,*c = loop do break [1,2]; end; test_ok([a,b,c] == [1,2,[]])
+a,b,*c = loop do break [*[]]; end; test_ok([a,b,c] == [nil,nil,[]])
+a,b,*c = loop do break [*[1]]; end; test_ok([a,b,c] == [1,nil,[]])
+a,b,*c = loop do break [*[1,2]]; end; test_ok([a,b,c] == [1,2,[]])
+
+a,b,*c = loop do break *[]; end; test_ok([a,b,c] == [nil,nil,[]])
+a,b,*c = loop do break *[1]; end; test_ok([a,b,c] == [1,nil,[]])
+a,b,*c = loop do break *[nil]; end; test_ok([a,b,c] == [nil,nil,[]])
+a,b,*c = loop do break *[[]]; end; test_ok([a,b,c] == [[],nil,[]])
+a,b,*c = loop do break *[1,2]; end; test_ok([a,b,c] == [1,2,[]])
+a,b,*c = loop do break *[*[]]; end; test_ok([a,b,c] == [nil,nil,[]])
+a,b,*c = loop do break *[*[1]]; end; test_ok([a,b,c] == [1,nil,[]])
+a,b,*c = loop do break *[*[1,2]]; end; test_ok([a,b,c] == [1,2,[]])
+
+def r(val); a = yield(); test_ok(a == val, 2); end
+r(nil){next}
+r(nil){next nil}
+r(1){next 1}
+r([]){next []}
+r([1]){next [1]}
+r([nil]){next [nil]}
+r([[]]){next [[]]}
+r([]){next [*[]]}
+r([1]){next [*[1]]}
+r([1,2]){next [*[1,2]]}
+
+r([]){next *[]}
+r([1]){next *[1]}
+r([nil]){next *[nil]}
+r([[]]){next *[[]]}
+r([]){next *[*[]]}
+r([1]){next *[*[1]]}
+r([1,2]){next *[*[1,2]]}
+
+def r(val); *a = yield(); test_ok(a == val, 2); end
+r([nil]){next}
+r([nil]){next nil}
+r([1]){next 1}
+r([]){next []}
+r([1]){next [1]}
+r([nil]){next [nil]}
+r([[]]){next [[]]}
+r([1,2]){next [1,2]}
+r([]){next [*[]]}
+r([1]){next [*[1]]}
+r([1,2]){next [*[1,2]]}
+
+def r(val); *a = *yield(); test_ok(a == val, 2); end
+r([[]]){next *[[]]}
+r([1,2]){next *[1,2]}
+r([1,2]){next *[*[1,2]]}
+
+def r(val); a,b,*c = yield(); test_ok([a,b,c] == val, 2); end
+r([nil,nil,[]]){next}
+r([nil,nil,[]]){next nil}
+r([1,nil,[]]){next 1}
+r([nil,nil,[]]){next []}
+r([1,nil,[]]){next [1]}
+r([nil,nil,[]]){next [nil]}
+r([[],nil,[]]){next [[]]}
+r([1,2,[]]){next [1,2]}
+r([nil,nil,[]]){next [*[]]}
+r([1,nil,[]]){next [*[1]]}
+r([1,2,[]]){next [*[1,2]]}
+
+def r(val); a,b,*c = *yield(); test_ok([a,b,c] == val, 2); end
+r([[],nil,[]]){next *[[]]}
+r([1,2,[]]){next *[1,2]}
+r([1,2,[]]){next *[*[1,2]]}
+
+test_check "condition"
+
+$x = '0';
+
+$x == $x && test_ok(true)
+$x != $x && test_ok(false)
+$x == $x || test_ok(false)
+$x != $x || test_ok(true)
+
+# first test to see if we can run the tests.
+
+test_check "if/unless";
+
+$x = 'test';
+test_ok(if $x == $x then true else false end)
+$bad = false
+unless $x == $x
+  $bad = true
+end
+test_ok(!$bad)
+test_ok(unless $x != $x then true else false end)
+
+test_check "case"
+
+case 5
+when 1, 2, 3, 4, 6, 7, 8
+  test_ok(false)
+when 5
+  test_ok(true)
+end
+
+case 5
+when 5
+  test_ok(true)
+when 1..10
+  test_ok(false)
+end
+
+case 5
+when 1..10
+  test_ok(true)
+else
+  test_ok(false)
+end
+
+case 5
+when 5
+  test_ok(true)
+else
+  test_ok(false)
+end
+
+case "foobar"
+when /^f.*r$/
+  test_ok(true)
+else
+  test_ok(false)
+end
+
+test_check "while/until";
+
+while_tmp = "while_tmp.#{$$}"
+tmp = open(while_tmp, "w")
+tmp.print "tvi925\n";
+tmp.print "tvi920\n";
+tmp.print "vt100\n";
+tmp.print "Amiga\n";
+tmp.print "paper\n";
+tmp.close
+
+# test break
+
+tmp = open(while_tmp, "r")
+test_ok(tmp.kind_of?(File))
+
+while line = tmp.gets()
+  break if /vt100/ =~ line
+end
+
+test_ok(!tmp.eof? && /vt100/ =~ line)
+tmp.close
+
+# test next
+$bad = false
+tmp = open(while_tmp, "r")
+while line = tmp.gets()
+  next if /vt100/ =~ line
+  $bad = 1 if /vt100/ =~ line
+end
+test_ok(!(!tmp.eof? || /vt100/ =~ line || $bad))
+tmp.close
+
+# test redo
+$bad = false
+tmp = open(while_tmp, "r")
+while line = tmp.gets()
+  lastline = line
+  line = line.gsub(/vt100/, 'VT100')
+  if lastline != line
+    line.gsub!('VT100', 'Vt100')
+    redo
+  end
+  $bad = 1 if /vt100/ =~ line
+  $bad = 1 if /VT100/ =~ line
+end
+test_ok(tmp.eof? && !$bad)
+tmp.close
+
+sum=0
+for i in 1..10
+  sum += i
+  i -= 1
+  if i > 0
+    redo
+  end
+end
+test_ok(sum == 220)
+
+# test interval
+$bad = false
+tmp = open(while_tmp, "r")
+while line = tmp.gets()
+  break if 3
+  case line
+  when /vt100/, /Amiga/, /paper/
+    $bad = true
+  end
+end
+test_ok(!$bad)
+tmp.close
+
+File.unlink while_tmp or `/bin/rm -f "#{while_tmp}"`
+test_ok(!File.exist?(while_tmp))
+
+i = 0
+until i>4
+  i+=1
+end
+test_ok(i>4)
+
+
+# exception handling
+test_check "exception";
+
+begin
+  raise "this must be handled"
+  test_ok(false)
+rescue
+  test_ok(true)
+end
+
+$bad = true
+begin
+  raise "this must be handled no.2"
+rescue
+  if $bad
+    $bad = false
+    retry
+    test_ok(false)
+  end
+end
+test_ok(true)
+
+# exception in rescue clause
+$string = "this must be handled no.3"
+begin
+  begin
+    raise "exception in rescue clause"
+  rescue
+    raise $string
+  end
+  test_ok(false)
+rescue => e
+  test_ok($! == e)
+  test_ok(e.message == $string)
+  test_ok(e != $string)
+end
+
+# exception in ensure clause
+begin
+  begin
+    raise "this must be handled no.4"
+  ensure
+    raise "exception in ensure clause"
+  end
+  test_ok(false)
+rescue
+  test_ok(true)
+end
+
+$bad = true
+begin
+  begin
+    raise "this must be handled no.5"
+  ensure
+    $bad = false
+  end
+rescue
+end
+test_ok(!$bad)
+
+$bad = true
+begin
+  begin
+    raise "this must be handled no.6"
+  ensure
+    $bad = false
+  end
+rescue
+end
+test_ok(!$bad)
+
+$bad = true
+while true
+  begin
+    break
+  ensure
+    $bad = false
+  end
+end
+test_ok(!$bad)
+
+test_ok(catch(:foo) {
+     loop do
+       loop do
+	 throw :foo, true
+	 break
+       end
+       break
+       test_ok(false)			# should not reach here
+     end
+     false
+   })
+
+test_check "array"
+test_ok([1, 2] + [3, 4] == [1, 2, 3, 4])
+test_ok([1, 2] * 2 == [1, 2, 1, 2])
+test_ok([1, 2] * ":" == "1:2")
+
+test_ok([1, 2].hash == [1, 2].hash)
+
+test_ok([1,2,3] & [2,3,4] == [2,3])
+test_ok([1,2,3] | [2,3,4] == [1,2,3,4])
+test_ok([1,2,3] - [2,3] == [1])
+
+$x = [0, 1, 2, 3, 4, 5]
+test_ok($x[2] == 2)
+test_ok($x[1..3] == [1, 2, 3])
+test_ok($x[1,3] == [1, 2, 3])
+
+$x[0, 2] = 10
+test_ok($x[0] == 10 && $x[1] == 2)
+
+$x[0, 0] = -1
+test_ok($x[0] == -1 && $x[1] == 10)
+
+$x[-1, 1] = 20
+test_ok($x[-1] == 20 && $x.pop == 20)
+
+# array and/or
+test_ok(([1,2,3]&[2,4,6]) == [2])
+test_ok(([1,2,3]|[2,4,6]) == [1,2,3,4,6])
+
+# compact
+$x = [nil, 1, nil, nil, 5, nil, nil]
+$x.compact!
+test_ok($x == [1, 5])
+
+# uniq
+$x = [1, 1, 4, 2, 5, 4, 5, 1, 2]
+$x.uniq!
+test_ok($x == [1, 4, 2, 5])
+
+# empty?
+test_ok(!$x.empty?)
+$x = []
+test_ok($x.empty?)
+
+# sort
+$x = ["it", "came", "to", "pass", "that", "..."]
+$x = $x.sort.join(" ")
+test_ok($x == "... came it pass that to")
+$x = [2,5,3,1,7]
+$x.sort!{|a,b| a<=>b}		# sort with condition
+test_ok($x == [1,2,3,5,7])
+$x.sort!{|a,b| b-a}		# reverse sort
+test_ok($x == [7,5,3,2,1])
+
+# split test
+$x = "The Book of Mormon"
+test_ok($x.split(//).reverse!.join == $x.reverse)
+test_ok($x.reverse == $x.reverse!)
+test_ok("1 byte string".split(//).reverse.join(":") == "g:n:i:r:t:s: :e:t:y:b: :1")
+$x = "a b c  d"
+test_ok($x.split == ['a', 'b', 'c', 'd'])
+test_ok($x.split(' ') == ['a', 'b', 'c', 'd'])
+test_ok(defined? "a".chomp)
+test_ok("abc".scan(/./) == ["a", "b", "c"])
+test_ok("1a2b3c".scan(/(\d.)/) == [["1a"], ["2b"], ["3c"]])
+# non-greedy match
+test_ok("a=12;b=22".scan(/(.*?)=(\d*);?/) == [["a", "12"], ["b", "22"]])
+
+$x = [1]
+test_ok(($x * 5).join(":") == '1:1:1:1:1')
+test_ok(($x * 1).join(":") == '1')
+test_ok(($x * 0).join(":") == '')
+
+*$x = *(1..7).to_a
+test_ok($x.size == 7)
+test_ok($x == [1, 2, 3, 4, 5, 6, 7])
+
+$x = [1,2,3]
+$x[1,0] = $x
+test_ok($x == [1,1,2,3,2,3])
+
+$x = [1,2,3]
+$x[-1,0] = $x
+test_ok($x == [1,2,1,2,3,3])
+
+$x = [1,2,3]
+$x.concat($x)
+test_ok($x == [1,2,3,1,2,3])
+
+test_check "hash"
+$x = {1=>2, 2=>4, 3=>6}
+
+test_ok($x[1] == 2)
+
+test_ok(begin
+     for k,v in $x
+       raise if k*2 != v
+     end
+     true
+   rescue
+     false
+   end)
+
+test_ok($x.length == 3)
+test_ok($x.has_key?(1))
+test_ok($x.has_value?(4))
+test_ok($x.values_at(2,3) == [4,6])
+test_ok($x == {1=>2, 2=>4, 3=>6})
+
+$z = $x.keys.sort.join(":")
+test_ok($z == "1:2:3")
+
+$z = $x.values.sort.join(":")
+test_ok($z == "2:4:6")
+test_ok($x == $x)
+
+$x.shift
+test_ok($x.length == 2)
+
+$z = [1,2]
+$x[$z] = 256
+test_ok($x[$z] == 256)
+
+$x = Hash.new(0)
+$x[1] = 1
+test_ok($x[1] == 1)
+test_ok($x[2] == 0)
+
+$x = Hash.new([])
+test_ok($x[22] == [])
+test_ok($x[22].equal?($x[22]))
+
+$x = Hash.new{[]}
+test_ok($x[22] == [])
+test_ok(!$x[22].equal?($x[22]))
+
+$x = Hash.new{|h,k| $z = k; h[k] = k*2}
+$z = 0
+test_ok($x[22] == 44)
+test_ok($z == 22)
+$z = 0
+test_ok($x[22] == 44)
+test_ok($z == 0)
+$x.default = 5
+test_ok($x[23] == 5)
+
+$x = Hash.new
+def $x.default(k)
+  $z = k
+  self[k] = k*2
+end
+$z = 0
+test_ok($x[22] == 44)
+test_ok($z == 22)
+$z = 0
+test_ok($x[22] == 44)
+test_ok($z == 0)
+
+test_check "iterator"
+
+# yield at top level
+test_ok(!defined?(yield))
+
+$x = [1, 2, 3, 4]
+$y = []
+
+# iterator over array
+for i in $x
+  $y.push i
+end
+test_ok($x == $y)
+
+# nested iterator
+def tt
+  1.upto(10) {|i|
+    yield i
+  }
+end
+
+i=0
+tt{|i| break if i == 5}
+test_ok(i == 0)
+
+def tt2(dummy)
+  yield 1
+end
+
+def tt3(&block)
+  tt2(raise(ArgumentError,""),&block)
+end
+
+$x = false
+begin
+  tt3{}
+rescue ArgumentError
+  $x = true
+rescue Exception
+end
+test_ok($x)
+
+def tt4 &block
+  tt2(raise(ArgumentError,""),&block)
+end
+$x = false
+begin
+  tt4{}
+rescue ArgumentError
+  $x = true
+rescue Exception
+end
+test_ok($x)
+
+# iterator break/redo/next/retry
+done = true
+loop{
+  break
+  done = false			# should not reach here
+}
+test_ok(done)
+
+done = false
+$bad = false
+loop {
+  break if done
+  done = true
+  next
+  $bad = true			# should not reach here
+}
+test_ok(!$bad)
+
+done = false
+$bad = false
+loop {
+  break if done
+  done = true
+  redo
+  $bad = true			# should not reach here
+}
+test_ok(!$bad)
+
+$x = []
+for i in 1 .. 7
+  $x.push i
+end
+test_ok($x.size == 7)
+test_ok($x == [1, 2, 3, 4, 5, 6, 7])
+
+# append method to built-in class
+class Array
+  def iter_test1
+    collect{|e| [e, yield(e)]}.sort{|a,b|a[1]<=>b[1]}
+  end
+  def iter_test2
+    a = collect{|e| [e, yield(e)]}
+    a.sort{|a,b|a[1]<=>b[1]}
+  end
+end
+$x = [[1,2],[3,4],[5,6]]
+test_ok($x.iter_test1{|x|x} == $x.iter_test2{|x|x})
+
+class IterTest
+  def initialize(e); @body = e; end
+
+  def each0(&block); @body.each(&block); end
+  def each1(&block); @body.each {|*x| block.call(*x) } end
+  def each2(&block); @body.each {|*x| block.call(x) } end
+  def each3(&block); @body.each {|x| block.call(*x) } end
+  def each4(&block); @body.each {|x| block.call(x) } end
+  def each5; @body.each {|*x| yield(*x) } end
+  def each6; @body.each {|*x| yield(x) } end
+  def each7; @body.each {|x| yield(*x) } end
+  def each8; @body.each {|x| yield(x) } end
+
+  def f(a)
+    a
+  end
+end
+test_ok(IterTest.new(nil).method(:f).to_proc.call([1]) == [1])
+m = /\w+/.match("abc")
+test_ok(IterTest.new(nil).method(:f).to_proc.call([m]) == [m])
+
+IterTest.new([0]).each0 {|x| test_ok(x == 0)}
+IterTest.new([1]).each1 {|x| test_ok(x == 1)}
+IterTest.new([2]).each2 {|x| test_ok(x == [2])}
+#IterTest.new([3]).each3 {|x| test_ok(x == 3)}
+IterTest.new([4]).each4 {|x| test_ok(x == 4)}
+IterTest.new([5]).each5 {|x| test_ok(x == 5)}
+IterTest.new([6]).each6 {|x| test_ok(x == [6])}
+#IterTest.new([7]).each7 {|x| test_ok(x == 7)}
+IterTest.new([8]).each8 {|x| test_ok(x == 8)}
+
+IterTest.new([[0]]).each0 {|x| test_ok(x == [0])}
+IterTest.new([[1]]).each1 {|x| test_ok(x == [1])}
+IterTest.new([[2]]).each2 {|x| test_ok(x == [[2]])}
+IterTest.new([[3]]).each3 {|x| test_ok(x == 3)}
+IterTest.new([[4]]).each4 {|x| test_ok(x == [4])}
+IterTest.new([[5]]).each5 {|x| test_ok(x == [5])}
+IterTest.new([[6]]).each6 {|x| test_ok(x == [[6]])}
+IterTest.new([[7]]).each7 {|x| test_ok(x == 7)}
+IterTest.new([[8]]).each8 {|x| test_ok(x == [8])}
+
+IterTest.new([[0,0]]).each0 {|*x| test_ok(x == [[0,0]])}
+IterTest.new([[8,8]]).each8 {|*x| test_ok(x == [[8,8]])}
+
+def m0(v)
+  v
+end
+
+def m1
+  m0(block_given?)
+end
+test_ok(m1{p 'test'})
+test_ok(!m1)
+
+def m
+  m0(block_given?,&Proc.new{})
+end
+test_ok(m1{p 'test'})
+test_ok(!m1)
+
+class C
+  include Enumerable
+  def initialize
+    @a = [1,2,3]
+  end
+  def each(&block)
+    @a.each(&block)
+  end
+end
+
+test_ok(C.new.collect{|n| n} == [1,2,3])
+
+test_ok(Proc == lambda{}.class)
+test_ok(Proc == Proc.new{}.class)
+lambda{|a|test_ok(a==1)}.call(1)
+def block_test(klass, &block)
+  test_ok(klass === block)
+end
+
+block_test(NilClass)
+block_test(Proc){}
+
+def call_argument_test(state, proc, *args)
+  x = state
+  begin
+    proc.call(*args)
+  rescue ArgumentError
+    x = !x
+  end
+  test_ok(x,2)
+end
+
+call_argument_test(true, lambda{||})
+call_argument_test(false, lambda{||}, 1)
+call_argument_test(true, lambda{|a,|}, 1)
+call_argument_test(false, lambda{|a,|})
+call_argument_test(false, lambda{|a,|}, 1,2)
+
+call_argument_test(true, Proc.new{||})
+call_argument_test(true, Proc.new{||}, 1)
+call_argument_test(true, Proc.new{|a,|}, 1)
+call_argument_test(true, Proc.new{|a,|})
+call_argument_test(true, Proc.new{|a,|}, 1,2)
+
+def block_get(&block)
+  block
+end
+
+test_ok(Proc == block_get{}.class)
+call_argument_test(true, block_get{||})
+call_argument_test(true, block_get{||}, 1)
+call_argument_test(true, block_get{|a,|}, 1)
+call_argument_test(true, block_get{|a,|})
+call_argument_test(true, block_get{|a,|}, 1,2)
+
+call_argument_test(true, block_get(&lambda{||}))
+call_argument_test(false, block_get(&lambda{||}),1)
+call_argument_test(true, block_get(&lambda{|a,|}),1)
+call_argument_test(false, block_get(&lambda{|a,|}),1,2)
+
+blk = block_get{11}
+test_ok(blk.class == Proc)
+test_ok(blk.to_proc.class == Proc)
+test_ok(blk.clone.call == 11)
+test_ok(block_get(&blk).class == Proc)
+
+lmd = lambda{44}
+test_ok(lmd.class == Proc)
+test_ok(lmd.to_proc.class == Proc)
+test_ok(lmd.clone.call == 44)
+test_ok(block_get(&lmd).class == Proc)
+
+test_ok(Proc.new{|a,| a}.yield(1,2,3) == 1)
+call_argument_test(true, Proc.new{|a,|}, 1,2)
+
+test_ok(Proc.new{|&b| b.call(10)}.call {|x| x} == 10)
+test_ok(Proc.new{|a,&b| b.call(a)}.call(12) {|x| x} == 12)
+
+def test_return1
+  Proc.new {
+    return 55
+  }.yield + 5
+end
+test_ok(test_return1() == 55)
+def test_return2
+  lambda {
+    return 55
+  }.call + 5
+end
+test_ok(test_return2() == 60)
+
+def proc_call(&b)
+  b.call
+end
+def proc_yield()
+  yield
+end
+def proc_return1
+  lambda{return 42}.call+1
+end
+test_ok(proc_return1() == 43)
+def proc_return2
+  ->{return 42}.call+1
+end
+test_ok(proc_return2() == 43)
+def proc_return3
+  proc_call{return 42}+1
+end
+test_ok(proc_return3() == 42)
+def proc_return4
+  proc_yield{return 42}+1
+end
+test_ok(proc_return4() == 42)
+
+def ljump_test(state, proc, *args)
+  x = state
+  begin
+    proc.call(*args)
+  rescue LocalJumpError
+    x = !x
+  end
+  test_ok(x,2)
+end
+
+ljump_test(false, block_get{break})
+ljump_test(true, lambda{break})
+
+def exit_value_test(&block)
+  block.call
+rescue LocalJumpError
+  $!.exit_value
+end
+
+test_ok(45 == exit_value_test{break 45})
+
+test_ok(55 == begin
+              block_get{break 55}.call
+            rescue LocalJumpError
+              $!.exit_value
+            end)
+
+def block_call(&block)
+  block.call
+end
+
+def test_b1
+  block_call{break 11}
+end
+test_ok(test_b1() == 11)
+
+def ljump_rescue(r)
+  begin
+    yield
+  rescue LocalJumpError => e
+    r if /from proc-closure/ =~ e.message
+  end
+end
+
+def test_b2
+  ljump_rescue(22) do
+    block_get{break 21}.call
+  end
+end
+test_ok(test_b2() == 22)
+
+def test_b3
+  ljump_rescue(33) do
+    Proc.new{break 31}.yield
+  end
+end
+test_ok(test_b3() == 33)
+
+def test_b4
+  lambda{break 44}.call
+end
+test_ok(test_b4() == 44)
+
+def test_b5
+  ljump_rescue(55) do
+    b = block_get{break 54}
+    block_call(&b)
+  end
+end
+test_ok(test_b5() == 55)
+
+def test_b6
+  b = lambda{break 67}
+  block_call(&b)
+  66
+end
+test_ok(test_b6() == 66)
+
+def util_r7
+  block_get{break 78}
+end
+
+def test_b7
+  b = util_r7()
+  ljump_rescue(77) do
+    block_call(&b)
+  end
+end
+test_ok(test_b7() == 77)
+
+def util_b8(&block)
+  block_call(&block)
+end
+
+def test_b8
+  util_b8{break 88}
+end
+test_ok(test_b8() == 88)
+
+def util_b9(&block)
+  lambda{block.call; 98}.call
+end
+
+def test_b9
+  util_b9{break 99}
+end
+test_ok(test_b9() == 99)
+
+def util_b10
+  util_b9{break 100}
+end
+
+def test_b10
+  util_b10()
+end
+test_ok(test_b10() == 100)
+
+def test_b11
+  ljump_rescue(111) do
+    loop do
+      Proc.new{break 110}.yield
+      break 112
+    end
+  end
+end
+test_ok(test_b11() == 111)
+
+def test_b12
+  loop do
+    break lambda{break 122}.call
+    break 121
+  end
+end
+test_ok(test_b12() == 122)
+
+def test_b13
+  ljump_rescue(133) do
+    while true
+      Proc.new{break 130}.yield
+      break 131
+    end
+  end
+end
+test_ok(test_b13() == 133)
+
+def test_b14
+  while true
+    break lambda{break 144}.call
+    break 143
+  end
+end
+test_ok(test_b14() == 144)
+
+def test_b15
+  [0].each {|c| yield 1 }
+  156
+end
+test_ok(test_b15{|e| break 155 } == 155)
+
+def marity_test(m)
+  method = method(m)
+  test_ok(method.arity == method.to_proc.arity, 2)
+end
+marity_test(:test_ok)
+marity_test(:marity_test)
+marity_test(:p)
+
+class ITER_TEST1
+   def a
+     block_given?
+   end
+end
+
+class ITER_TEST2 < ITER_TEST1
+   def a
+     test_ok(super)
+     super
+   end
+end
+test_ok(ITER_TEST2.new.a {})
+
+class ITER_TEST3
+  def foo x
+    return yield if block_given?
+    x
+  end
+end
+
+class ITER_TEST4 < ITER_TEST3
+  def foo x
+    test_ok(super == yield)
+    test_ok(super(x, &nil) == x)
+  end
+end
+
+ITER_TEST4.new.foo(44){55}
+
+class ITER_TEST5
+   def tt(aa)
+     aa
+   end
+
+   def uu(a)
+      class << self
+         define_method(:tt) do |sym|
+            super(sym)
+         end
+      end
+   end
+
+   def xx(*x)
+     x.size
+   end
+end
+
+a = ITER_TEST5.new
+a.uu(12)
+test_ok(a.tt(1) == 1)
+
+class ITER_TEST6 < ITER_TEST5
+   def xx(*a)
+      a << 12
+      super
+   end
+end
+
+test_ok(ITER_TEST6.new.xx([24]) == 2)
+
+test_check "float"
+test_ok(2.6.floor == 2)
+test_ok((-2.6).floor == -3)
+test_ok(2.6.ceil == 3)
+test_ok((-2.6).ceil == -2)
+test_ok(2.6.truncate == 2)
+test_ok((-2.6).truncate == -2)
+test_ok(2.6.round == 3)
+test_ok((-2.4).truncate == -2)
+test_ok((13.4 % 1 - 0.4).abs < 0.0001)
+nan = 0.0/0
+def nan_test(x,y)
+  test_ok(x != y)
+  test_ok((x < y) == false)
+  test_ok((x > y) == false)
+  test_ok((x <= y) == false)
+  test_ok((x >= y) == false)
+end
+nan_test(nan, nan)
+nan_test(nan, 0)
+nan_test(nan, 1)
+nan_test(nan, -1)
+nan_test(nan, 1000)
+nan_test(nan, -1000)
+nan_test(nan, 1_000_000_000_000)
+nan_test(nan, -1_000_000_000_000)
+nan_test(nan, 100.0);
+nan_test(nan, -100.0);
+nan_test(nan, 0.001);
+nan_test(nan, -0.001);
+nan_test(nan, 1.0/0);
+nan_test(nan, -1.0/0);
+
+#s = "3.7517675036461267e+17"
+#test_ok(s == sprintf("%.16e", s.to_f))
+f = 3.7517675036461267e+17
+test_ok(f == sprintf("%.16e", f).to_f)
+
+
+test_check "bignum"
+def fact(n)
+  return 1 if n == 0
+  f = 1
+  while n>0
+    f *= n
+    n -= 1
+  end
+  return f
+end
+$x = fact(40)
+test_ok($x == $x)
+test_ok($x == fact(40))
+test_ok($x < $x+2)
+test_ok($x > $x-2)
+test_ok($x == 815915283247897734345611269596115894272000000000)
+test_ok($x != 815915283247897734345611269596115894272000000001)
+test_ok($x+1 == 815915283247897734345611269596115894272000000001)
+test_ok($x/fact(20) == 335367096786357081410764800000)
+$x = -$x
+test_ok($x == -815915283247897734345611269596115894272000000000)
+test_ok(2-(2**32) == -(2**32-2))
+test_ok(2**32 - 5 == (2**32-3)-2)
+
+$good = true;
+for i in 1000..1014
+  $good = false if ((1 << i) != (2**i))
+end
+test_ok($good)
+
+$good = true;
+n1= 1 << 1000
+for i in 1000..1014
+  $good = false if ((1 << i) != n1)
+  n1 *= 2
+end
+test_ok($good)
+
+$good = true;
+n2=n1
+for i in 1..10
+  n1 = n1 / 2
+  n2 = n2 >> 1
+  $good = false if (n1 != n2)
+end
+test_ok($good)
+
+$good = true;
+for i in 4000..4096
+  n1 = 1 << i;
+  if (n1**2-1) / (n1+1) != (n1-1)
+    $good = false
+  end
+end
+test_ok($good)
+
+b = 10**80
+a = b * 9 + 7
+test_ok(7 == a.modulo(b))
+test_ok(-b + 7 == a.modulo(-b))
+test_ok(b + -7 == (-a).modulo(b))
+test_ok(-7 == (-a).modulo(-b))
+test_ok(7 == a.remainder(b))
+test_ok(7 == a.remainder(-b))
+test_ok(-7 == (-a).remainder(b))
+test_ok(-7 == (-a).remainder(-b))
+
+test_ok(10**40+10**20 == 10000000000000000000100000000000000000000)
+test_ok(10**40/10**20 == 100000000000000000000)
+
+a = 677330545177305025495135714080
+b = 14269972710765292560
+test_ok(a % b == 0)
+test_ok(-a % b == 0)
+
+def shift_test(a)
+  b = a / (2 ** 32)
+  c = a >> 32
+  test_ok(b == c)
+
+  b = a * (2 ** 32)
+  c = a << 32
+  test_ok(b == c)
+end
+
+shift_test(-4518325415524767873)
+shift_test(-0xfffffffffffffffff)
+
+test_check "string & char"
+
+test_ok("abcd" == "abcd")
+test_ok("abcd" =~ /abcd/)
+test_ok("abcd" === "abcd")
+# compile time string concatenation
+test_ok("ab" "cd" == "abcd")
+test_ok("#{22}aa" "cd#{44}" == "22aacd44")
+test_ok("#{22}aa" "cd#{44}" "55" "#{66}" == "22aacd445566")
+test_ok("abc" !~ /^$/)
+test_ok("abc\n" !~ /^$/)
+test_ok("abc" !~ /^d*$/)
+test_ok(("abc" =~ /d*$/) == 3)
+test_ok("" =~ /^$/)
+test_ok("\n" =~ /^$/)
+test_ok("a\n\n" =~ /^$/)
+test_ok("abcabc" =~ /.*a/ && $& == "abca")
+test_ok("abcabc" =~ /.*c/ && $& == "abcabc")
+test_ok("abcabc" =~ /.*?a/ && $& == "a")
+test_ok("abcabc" =~ /.*?c/ && $& == "abc")
+test_ok(/(.|\n)*?\n(b|\n)/ =~ "a\nb\n\n" && $& == "a\nb")
+
+test_ok(/^(ab+)+b/ =~ "ababb" && $& == "ababb")
+test_ok(/^(?:ab+)+b/ =~ "ababb" && $& == "ababb")
+test_ok(/^(ab+)+/ =~ "ababb" && $& == "ababb")
+test_ok(/^(?:ab+)+/ =~ "ababb" && $& == "ababb")
+
+test_ok(/(\s+\d+){2}/ =~ " 1 2" && $& == " 1 2")
+test_ok(/(?:\s+\d+){2}/ =~ " 1 2" && $& == " 1 2")
+
+$x = <<END;
+ABCD
+ABCD
+END
+$x.gsub!(/((.|\n)*?)B((.|\n)*?)D/, '\1\3')
+test_ok($x == "AC\nAC\n")
+
+test_ok("foobar" =~ /foo(?=(bar)|(baz))/)
+test_ok("foobaz" =~ /foo(?=(bar)|(baz))/)
+
+$foo = "abc"
+test_ok("#$foo = abc" == "abc = abc")
+test_ok("#{$foo} = abc" == "abc = abc")
+
+foo = "abc"
+test_ok("#{foo} = abc" == "abc = abc")
+
+test_ok('-' * 5 == '-----')
+test_ok('-' * 1 == '-')
+test_ok('-' * 0 == '')
+
+foo = '-'
+test_ok(foo * 5 == '-----')
+test_ok(foo * 1 == '-')
+test_ok(foo * 0 == '')
+
+$x = "a.gif"
+test_ok($x.sub(/.*\.([^\.]+)$/, '\1') == "gif")
+test_ok($x.sub(/.*\.([^\.]+)$/, 'b.\1') == "b.gif")
+test_ok($x.sub(/.*\.([^\.]+)$/, '\2') == "")
+test_ok($x.sub(/.*\.([^\.]+)$/, 'a\2b') == "ab")
+test_ok($x.sub(/.*\.([^\.]+)$/, '<\&>') == "<a.gif>")
+
+# character constants(assumes ASCII)
+test_ok("a"[0] == ?a)
+test_ok(?a == ?a)
+test_ok(?\C-a == "\1")
+test_ok(?\M-a == "\341")
+test_ok(?\M-\C-a == "\201")
+test_ok("a".upcase![0] == ?A)
+test_ok("A".downcase![0] == ?a)
+test_ok("abc".tr!("a-z", "A-Z") == "ABC")
+test_ok("aabbcccc".tr_s!("a-z", "A-Z") == "ABC")
+test_ok("abcc".squeeze!("a-z") == "abc")
+test_ok("abcd".delete!("bc") == "ad")
+
+$x = "abcdef"
+$y = [ ?a, ?b, ?c, ?d, ?e, ?f ]
+$bad = false
+$x.each_byte {|i|
+  if i.chr != $y.shift
+    $bad = true
+    break
+  end
+}
+test_ok(!$bad)
+
+s = "a string"
+s[0..s.size]="another string"
+test_ok(s == "another string")
+
+s = <<EOS
+#{
+[1,2,3].join(",")
+}
+EOS
+test_ok(s == "1,2,3\n")
+test_ok("Just".to_i(36) == 926381)
+test_ok("-another".to_i(36) == -23200231779)
+test_ok(1299022.to_s(36) == "ruby")
+test_ok(-1045307475.to_s(36) == "-hacker")
+test_ok("Just_another_Ruby_hacker".to_i(36) == 265419172580680477752431643787347)
+test_ok(-265419172580680477752431643787347.to_s(36) == "-justanotherrubyhacker")
+
+a = []
+(0..255).each {|n|
+  ch = [n].pack("C")
+  a.push ch if /a#{Regexp.quote ch}b/x =~ "ab"
+}
+test_ok(a.size == 0)
+
+test_check "assignment"
+a = nil
+test_ok(defined?(a))
+test_ok(a == nil)
+
+# multiple assignment
+a, b = 1, 2
+test_ok(a == 1 && b == 2)
+
+a, b = b, a
+test_ok(a == 2 && b == 1)
+
+a, = 1,2
+test_ok(a == 1)
+
+a, *b = 1, 2, 3
+test_ok(a == 1 && b == [2, 3])
+
+a, (b, c), d = 1, [2, 3], 4
+test_ok(a == 1 && b == 2 && c == 3 && d == 4)
+
+*a = 1, 2, 3
+test_ok(a == [1, 2, 3])
+
+*a = 4
+test_ok(a == [4])
+
+*a = nil
+test_ok(a == [nil])
+
+test_check "call"
+def aaa(a, b=100, *rest)
+  res = [a, b]
+  res += rest if rest
+  return res
+end
+
+# not enough argument
+begin
+  aaa()				# need at least 1 arg
+  test_ok(false)
+rescue
+  test_ok(true)
+end
+
+begin
+  aaa				# no arg given (exception raised)
+  test_ok(false)
+rescue
+  test_ok(true)
+end
+
+test_ok(aaa(1) == [1, 100])
+test_ok(aaa(1, 2) == [1, 2])
+test_ok(aaa(1, 2, 3, 4) == [1, 2, 3, 4])
+test_ok(aaa(1, *[2, 3, 4]) == [1, 2, 3, 4])
+
+test_check "proc"
+$proc = Proc.new{|i| i}
+test_ok($proc.call(2) == 2)
+test_ok($proc.call(3) == 3)
+
+$proc = Proc.new{|i| i*2}
+test_ok($proc.call(2) == 4)
+test_ok($proc.call(3) == 6)
+
+Proc.new{
+  iii=5				# nested local variable
+  $proc = Proc.new{|i|
+    iii = i
+  }
+  $proc2 = Proc.new {
+    $x = iii			# nested variables shared by procs
+  }
+  # scope of nested variables
+  test_ok(defined?(iii))
+}.call
+test_ok(!defined?(iii))		# out of scope
+
+loop{iii=5; test_ok(eval("defined? iii")); break}
+loop {
+  iii = 10
+  def dyna_var_check
+    loop {
+      test_ok(!defined?(iii))
+      break
+    }
+  end
+  dyna_var_check
+  break
+}
+$x=0
+$proc.call(5)
+$proc2.call
+test_ok($x == 5)
+
+if defined? Process.kill
+  test_check "signal"
+
+  $x = 0
+  trap "SIGINT", Proc.new{|sig| $x = 2}
+  Process.kill "SIGINT", $$
+  100.times {
+    sleep 0.1
+    break if $x != 0
+  }
+  test_ok($x == 2)
+
+  trap "SIGINT", Proc.new{raise "Interrupt"}
+
+  x = false
+  begin
+    Process.kill "SIGINT", $$
+    sleep 0.1
+  rescue
+    x = $!
+  end
+  test_ok(x && /Interrupt/ =~ x.message)
+end
+
+test_check "eval"
+test_ok(eval("") == nil)
+$bad=false
+eval 'while false; $bad = true; print "foo\n" end'
+test_ok(!$bad)
+
+test_ok(eval('Object'))
+test_ok(eval('true'))
+test_ok(!eval('nil'))
+test_ok(!eval('false'))
+
+$foo = 'test_ok(true)'
+begin
+  eval $foo
+rescue
+  test_ok(false)
+end
+
+test_ok(eval("$foo") == 'test_ok(true)')
+test_ok(eval("true") == true)
+i = 5
+test_ok(eval("i == 5"))
+test_ok(eval("i") == 5)
+test_ok(eval("defined? i"))
+
+# eval with binding
+def test_ev
+  local1 = "local1"
+  lambda {
+    local2 = "local2"
+    return binding
+  }.call
+end
+
+$x = test_ev
+test_ok(eval("local1", $x) == "local1") # normal local var
+test_ok(eval("local2", $x) == "local2") # nested local var
+$bad = true
+begin
+  p eval("local1")
+rescue NameError		# must raise error
+  $bad = false
+end
+test_ok(!$bad)
+
+module EvTest
+  EVTEST1 = 25
+  evtest2 = 125
+  $x = binding
+end
+test_ok(eval("EVTEST1", $x) == 25)	# constant in module
+test_ok(eval("evtest2", $x) == 125)	# local var in module
+$bad = true
+begin
+  eval("EVTEST1")
+rescue NameError		# must raise error
+  $bad = false
+end
+test_ok(!$bad)
+
+x = binding #! YARV Limitation: Proc.new{}
+eval "i4 = 1", x
+test_ok(eval("i4", x) == 1)
+x = Proc.new{binding}.call #! YARV Limitation: Proc.new{Proc.new{}}.call
+eval "i4 = 22", x
+test_ok(eval("i4", x) == 22)
+$x = []
+x = Proc.new{binding}.call #! YARV Limitation: Proc.new{Proc.new{}}.call
+eval "(0..9).each{|i5| $x[i5] = Proc.new{i5*2}}", x
+test_ok($x[4].call == 8)
+
+x = binding
+eval "i = 1", x
+test_ok(eval("i", x) == 1)
+x = Proc.new{binding}.call
+eval "i = 22", x
+test_ok(eval("i", x) == 22)
+$x = []
+x = Proc.new{binding}.call
+eval "(0..9).each{|i5| $x[i5] = Proc.new{i5*2}}", x
+test_ok($x[4].call == 8)
+x = Proc.new{binding}.call
+eval "for i6 in 1..1; j6=i6; end", x
+test_ok(eval("defined? i6", x))
+test_ok(eval("defined? j6", x))
+
+Proc.new {
+  p = binding
+  eval "foo11 = 1", p
+  foo22 = 5
+  Proc.new{foo11=22}.call
+  Proc.new{foo22=55}.call
+  test_ok(eval("foo11", p) == eval("foo11"))
+  test_ok(eval("foo11") == 1)
+  test_ok(eval("foo22", p) == eval("foo22"))
+  test_ok(eval("foo22") == 55)
+}.call if false #! YARV Limitation
+
+#! YARV Limitation: p1 = Proc.new{i7 = 0; Proc.new{i7}}.call
+p1 = Proc.new{i7 = 0; binding}.call
+#! YARV Limitation: test_ok(p1.call == 0)
+eval "i7=5", p1
+#! YARV Limitation: test_ok(p1.call == 5)
+test_ok(!defined?(i7))
+
+if false #! YARV Limitation
+p1 = Proc.new{i7 = 0; Proc.new{i7}}.call
+i7 = nil
+test_ok(p1.call == 0)
+eval "i7=1", p1
+test_ok(p1.call == 1)
+eval "i7=5", p1
+test_ok(p1.call == 5)
+test_ok(i7 == nil)
+end
+
+# WASI doesn't support spawning a new process for now.
+unless /wasi/ =~ RUBY_PLATFORM
+test_check "system"
+test_ok(`echo foobar` == "foobar\n")
+test_ok(`./miniruby -e 'print "foobar"'` == 'foobar')
+
+script_tmp = "script_tmp.#{$$}"
+tmp = open(script_tmp, "w")
+tmp.print "print $zzz\n";
+tmp.close
+
+test_ok(`./miniruby -s #{script_tmp} -zzz` == 'true')
+test_ok(`./miniruby -s #{script_tmp} -zzz=555` == '555')
+
+tmp = open(script_tmp, "w")
+tmp.print "#! /usr/local/bin/ruby -s\n";
+tmp.print "print $zzz\n";
+tmp.close
+
+test_ok(`./miniruby #{script_tmp} -zzz=678` == '678')
+
+tmp = open(script_tmp, "w")
+tmp.print "this is a leading junk\n";
+tmp.print "#! /usr/local/bin/ruby -s\n";
+tmp.print "print $zzz\n";
+tmp.print "__END__\n";
+tmp.print "this is a trailing junk\n";
+tmp.close
+
+test_ok(`./miniruby -x #{script_tmp}` == '')
+test_ok(`./miniruby -x #{script_tmp} -zzz=555` == '555')
+
+tmp = open(script_tmp, "w")
+for i in 1..5
+  tmp.print i, "\n"
+end
+tmp.close
+
+`./miniruby -i.bak -pe '$_.sub!(/^[0-9]+$/){$&.to_i * 5}' #{script_tmp}`
+done = true
+tmp = open(script_tmp, "r")
+while tmp.gets
+  if $_.to_i % 5 != 0
+    done = false
+    break
+  end
+end
+tmp.close
+test_ok(done)
+
+File.unlink script_tmp or `/bin/rm -f "#{script_tmp}"`
+File.unlink "#{script_tmp}.bak" or `/bin/rm -f "#{script_tmp}.bak"`
+end # not /wasi/ =~ RUBY_PLATFORM
+
+test_check "const"
+TEST1 = 1
+TEST2 = 2
+
+module Const
+  TEST3 = 3
+  TEST4 = 4
+end
+
+module Const2
+  TEST3 = 6
+  TEST4 = 8
+end
+
+include Const
+
+test_ok([TEST1,TEST2,TEST3,TEST4] == [1,2,3,4])
+
+include Const2
+STDERR.print "intentionally redefines TEST3, TEST4\n" if $VERBOSE
+test_ok([TEST1,TEST2,TEST3,TEST4] == [1,2,6,8])
+
+
+test_ok((String <=> Object) == -1)
+test_ok((Object <=> String) == 1)
+test_ok((Array <=> String) == nil)
+
+test_check "clone"
+foo = Object.new
+def foo.test
+  "test"
+end
+bar = foo.clone
+def bar.test2
+  "test2"
+end
+
+test_ok(bar.test2 == "test2")
+test_ok(bar.test == "test")
+test_ok(foo.test == "test")
+
+begin
+  foo.test2
+  test_ok false
+rescue NoMethodError
+  test_ok true
+end
+
+module M001; end
+module M002; end
+module M003; include M002; end
+module M002; include M001; end
+module M003; include M002; end
+
+test_ok(M003.ancestors == [M003, M002, M001])
+
+test_check "marshal"
+$x = [1,2,3,[4,5,"foo"],{1=>"bar"},2.5,fact(30)]
+$y = Marshal.dump($x)
+test_ok($x == Marshal.load($y))
+
+StrClone=String.clone;
+test_ok(Marshal.load(Marshal.dump(StrClone.new("abc"))).class == StrClone)
+
+[[1,2,3,4], [81, 2, 118, 3146]].each { |w,x,y,z|
+  a = (x.to_f + y.to_f / z.to_f) * Math.exp(w.to_f / (x.to_f + y.to_f / z.to_f))
+  ma = Marshal.dump(a)
+  b = Marshal.load(ma)
+  test_ok(a == b)
+}
+
+test_check "pack"
+
+$format = "c2x5CCxsdils_l_a6";
+# Need the expression in here to force ary[5] to be numeric.  This avoids
+# test2 failing because ary2 goes str->numeric->str and ary does not.
+ary = [1,-100,127,128,32767,987.654321098 / 100.0,12345,123456,-32767,-123456,"abcdef"]
+$x = ary.pack($format)
+ary2 = $x.unpack($format)
+
+test_ok(ary.length == ary2.length)
+test_ok(ary.join(':') == ary2.join(':'))
+test_ok($x =~ /def/)
+
+$x = [-1073741825]
+test_ok($x.pack("q").unpack("q") == $x)
+
+test_check "math"
+test_ok(Math.sqrt(4) == 2)
+
+include Math
+test_ok(sqrt(4) == 2)
+
+test_check "struct"
+struct_test = Struct.new("Test", :foo, :bar)
+test_ok(struct_test == Struct::Test)
+
+test = struct_test.new(1, 2)
+test_ok(test.foo == 1 && test.bar == 2)
+test_ok(test[0] == 1 && test[1] == 2)
+
+a, b = test.to_a
+test_ok(a == 1 && b == 2)
+
+test[0] = 22
+test_ok(test.foo == 22)
+
+test.bar = 47
+test_ok(test.bar == 47)
+
+test_check "variable"
+test_ok($$.instance_of?(Integer))
+
+# read-only variable
+begin
+  $$ = 5
+  test_ok false
+rescue NameError
+  test_ok true
+end
+
+foobar = "foobar"
+$_ = foobar
+test_ok($_ == foobar)
+
+class Gods
+  @@rule = "Uranus"
+  def ruler0
+    @@rule
+  end
+
+  def self.ruler1		# <= per method definition style
+    @@rule
+  end
+  class << self			# <= multiple method definition style
+    def ruler2
+      @@rule
+    end
+  end
+end
+
+module Olympians
+  @@rule ="Zeus"
+  def ruler3
+    @@rule
+  end
+end
+
+class Titans < Gods
+  @@rule = "Cronus"		# modifies @@rule in Gods
+  include Olympians
+  def ruler4
+    @@rule
+  end
+end
+
+test_ok(Gods.new.ruler0 == "Cronus")
+test_ok(Gods.ruler1 == "Cronus")
+test_ok(Gods.ruler2 == "Cronus")
+test_ok(Titans.ruler1 == "Cronus")
+test_ok(Titans.ruler2 == "Cronus")
+atlas = Titans.new
+test_ok(atlas.ruler0 == "Cronus")
+test_ok(atlas.ruler3 == "Zeus")
+begin
+  atlas.ruler4
+rescue RuntimeError => e
+  test_ok(e.message.include?("class variable @@rule of Olympians is overtaken by Gods"))
+else
+  test_ok(false)
+end
+test_ok(atlas.ruler3 == "Zeus")
+
+test_check "trace"
+$x = 1234
+$y = 0
+trace_var :$x, Proc.new{$y = $x}
+$x = 40414
+test_ok($y == $x)
+
+untrace_var :$x
+$x = 19660208
+test_ok($y != $x)
+
+trace_var :$x, Proc.new{$x *= 2}
+$x = 5
+test_ok($x == 10)
+
+untrace_var :$x
+
+test_check "defined?"
+
+test_ok(defined?($x))		# global variable
+test_ok(defined?($x) == 'global-variable')# returns description
+
+foo=5
+test_ok(defined?(foo))		# local variable
+
+test_ok(defined?(Array))	# constant
+test_ok(defined?(Object.new))	# method
+test_ok(!defined?(Object.print))# private method
+test_ok(defined?(1 == 2))	# operator expression
+
+class Foo
+  def foo
+    p :foo
+  end
+  protected :foo
+  def bar(f)
+    test_ok(defined?(self.foo))
+    test_ok(defined?(f.foo))
+  end
+end
+f = Foo.new
+test_ok(defined?(f.foo) == nil)
+f.bar(f)
+
+def defined_test
+  return !defined?(yield)
+end
+
+test_ok(defined_test)		# not iterator
+test_ok(!defined_test{})	# called as iterator
+
+test_check "alias"
+class Alias0
+  def foo; "foo" end
+end
+class Alias1 < Alias0
+  alias bar foo
+  def foo; "foo+" + super end
+end
+class Alias2 < Alias1
+  alias baz foo
+  undef foo
+end
+
+x = Alias2.new
+test_ok(x.bar == "foo")
+test_ok(x.baz == "foo+foo")
+
+# test_check for cache
+test_ok(x.baz == "foo+foo")
+
+class Alias3 < Alias2
+  def foo
+    defined? super
+  end
+  def bar
+    defined? super
+  end
+  def quux
+    defined? super
+  end
+end
+x = Alias3.new
+test_ok(!x.foo)
+test_ok(x.bar)
+test_ok(!x.quux)
+
+test_check "path"
+test_ok(File.basename("a") == "a")
+test_ok(File.basename("a/b") == "b")
+test_ok(File.basename("a/b/") == "b")
+test_ok(File.basename("/") == "/")
+test_ok(File.basename("//") == "/")
+test_ok(File.basename("///") == "/")
+test_ok(File.basename("a/b////") == "b")
+test_ok(File.basename("a.rb", ".rb") == "a")
+test_ok(File.basename("a.rb///", ".rb") == "a")
+test_ok(File.basename("a.rb///", ".*") == "a")
+test_ok(File.basename("a.rb///", ".c") == "a.rb")
+test_ok(File.dirname("a") == ".")
+test_ok(File.dirname("/") == "/")
+test_ok(File.dirname("/a") == "/")
+test_ok(File.dirname("a/b") == "a")
+test_ok(File.dirname("a/b/c") == "a/b")
+test_ok(File.dirname("/a/b/c") == "/a/b")
+test_ok(File.dirname("/a/b/") == "/a")
+test_ok(File.dirname("/a/b///") == "/a")
+case Dir.pwd
+when %r'\A\w:'
+  test_ok(/\A\w:\/\z/ =~ File.expand_path(".", "/"))
+  test_ok(/\A\w:\/a\z/ =~ File.expand_path("a", "/"))
+  dosish = true
+when %r'\A//'
+  test_ok(%r'\A//[^/]+/[^/]+\z' =~ File.expand_path(".", "/"))
+  test_ok(%r'\A//[^/]+/[^/]+/a\z' =~ File.expand_path(".", "/"))
+  dosish = true
+else
+  test_ok(File.expand_path(".", "/") == "/")
+  test_ok(File.expand_path("sub", "/") == "/sub")
+end
+if dosish
+  test_ok(File.expand_path("/", "//machine/share/sub") == "//machine/share")
+  test_ok(File.expand_path("/dir", "//machine/share/sub") == "//machine/share/dir")
+  test_ok(File.expand_path("/", "z:/sub") == "z:/")
+  test_ok(File.expand_path("/dir", "z:/sub") == "z:/dir")
+end
+test_ok(File.expand_path(".", "//") == "//")
+test_ok(File.expand_path("sub", "//") == "//sub")
+
+# test_check "Proc#binding"
+ObjectSpace.each_object(Proc){|o|
+  begin
+    b = o.binding
+    eval 'self', b
+  rescue ArgumentError
+  end
+}
+
+test_check "gc"
+begin
+  1.upto(10000) {
+    tmp = [0,1,2,3,4,5,6,7,8,9]
+  }
+  tmp = nil
+  test_ok true
+rescue
+  test_ok false
+end
+class S
+  def initialize(a)
+    @a = a
+  end
+end
+l=nil
+100000.times {
+  l = S.new(l)
+}
+GC.start
+test_ok true   # reach here or dumps core
+l = []
+100000.times {
+  l.push([l])
+}
+GC.start
+test_ok true   # reach here or dumps core
+
+ObjectSpace.each_object{|o|
+  o.class.name
+}
+
+test_ok true   # reach here or dumps core
+
+PROGRESS.finish
+if $failed > 0
+  printf "not ok/test: %d failed %d\n", $ntest, $failed
+else
+  printf "end of test(test: %d)\n", $ntest
+end
diff --git a/benchmark/README.md b/benchmark/README.md
new file mode 100644
index 0000000000..e11381cad9
--- /dev/null
+++ b/benchmark/README.md
@@ -0,0 +1,74 @@
+# ruby/benchmark
+
+This directory has benchmark definitions to be run with
+[benchmark\_driver.gem](https://github.com/benchmark-driver/benchmark-driver).
+
+## Normal usage
+
+Execute `gem install benchmark_driver` and run a command like:
+
+```bash
+# Run a benchmark script with the ruby in the $PATH
+benchmark-driver benchmark/app_fib.rb
+
+# Run benchmark scripts with multiple Ruby executables or options
+benchmark-driver benchmark/*.rb -e /path/to/ruby -e '/path/to/ruby --jit'
+
+# Or compare Ruby versions managed by rbenv
+benchmark-driver benchmark/*.rb --rbenv '2.5.1;2.6.0-preview2 --jit'
+
+# You can collect many metrics in many ways
+benchmark-driver benchmark/*.rb --runner memory --output markdown
+
+# Some are defined with YAML for complex setup or accurate measurement
+benchmark-driver benchmark/*.yml
+```
+
+See also:
+
+```console
+Usage: benchmark-driver [options] RUBY|YAML...
+    -r, --runner TYPE                Specify runner type: ips, time, memory, once, block (default: ips)
+    -o, --output TYPE                Specify output type: compare, simple, markdown, record, all (default: compare)
+    -e, --executables EXECS          Ruby executables (e1::path1 arg1; e2::path2 arg2;...)
+        --rbenv VERSIONS             Ruby executables in rbenv (x.x.x arg1;y.y.y arg2;...)
+        --repeat-count NUM           Try benchmark NUM times and use the fastest result or the worst memory usage
+        --repeat-result TYPE         Yield "best", "average" or "worst" result with --repeat-count (default: best)
+        --alternate                  Alternate executables instead of running the same executable in a row with --repeat-count
+        --bundler                    Install and use gems specified in Gemfile
+        --filter REGEXP              Filter out benchmarks with given regexp
+        --run-duration SECONDS       Warmup estimates loop_count to run for this duration (default: 3)
+        --timeout SECONDS            Timeout ruby command execution with timeout(1)
+    -v, --verbose                    Verbose mode. Multiple -v options increase visilibity (max: 2)
+```
+
+## make benchmark
+
+Using `make benchmark`, `make update-benchmark-driver` automatically downloads
+the supported version of benchmark\_driver, and it runs benchmarks with the downloaded
+benchmark\_driver.
+
+```bash
+# Run all benchmarks with the ruby in the $PATH and the built ruby
+make benchmark
+
+# Or compare with specific ruby binary
+make benchmark COMPARE_RUBY="/path/to/ruby --jit"
+
+# Run vm benchmarks
+make benchmark ITEM=vm
+
+# Run some limited benchmarks in ITEM-matched files
+make benchmark ITEM=vm OPTS=--filter=block
+
+# You can specify the benchmark by an exact filename instead of using the default argument:
+# ARGS = $$(find $(srcdir)/benchmark -maxdepth 1 -name '*$(ITEM)*.yml' -o -name '*$(ITEM)*.rb')
+make benchmark ARGS=benchmark/erb_render.yml
+
+# You can specify any option via $OPTS
+make benchmark OPTS="--help"
+
+# With `make benchmark`, some special runner plugins are available:
+#   -r peak, -r size, -r total, -r utime, -r stime, -r cutime, -r cstime
+make benchmark ITEM=vm_bigarray OPTS="-r peak"
+```
diff --git a/benchmark/bm_app_answer.rb b/benchmark/app_answer.rb
index 3cd8a8fd37..3cd8a8fd37 100644
--- a/benchmark/bm_app_answer.rb
+++ b/benchmark/app_answer.rb
diff --git a/benchmark/app_aobench.rb b/benchmark/app_aobench.rb
new file mode 100644
index 0000000000..16296af12b
--- /dev/null
+++ b/benchmark/app_aobench.rb
@@ -0,0 +1,297 @@
+# coding: US-ASCII
+
+# AO render benchmark
+# Original program (C) Syoyo Fujita in Javascript (and other languages)
+#      https://code.google.com/p/aobench/
+# Ruby(yarv2llvm) version by Hideki Miura
+#
+
+IMAGE_WIDTH = 256
+IMAGE_HEIGHT = 256
+NSUBSAMPLES = 2
+NAO_SAMPLES = 8
+
+srand(0)
+
+class Vec
+  def initialize(x, y, z)
+    @x = x
+    @y = y
+    @z = z
+  end
+
+  attr_accessor :x, :y, :z
+
+  def vadd(b)
+    Vec.new(@x + b.x, @y + b.y, @z + b.z)
+  end
+
+  def vsub(b)
+    Vec.new(@x - b.x, @y - b.y, @z - b.z)
+  end
+
+  def vcross(b)
+    Vec.new(@y * b.z - @z * b.y,
+            @z * b.x - @x * b.z,
+            @x * b.y - @y * b.x)
+  end
+
+  def vdot(b)
+    @x * b.x + @y * b.y + @z * b.z
+  end
+
+  def vlength
+    Math.sqrt(@x * @x + @y * @y + @z * @z)
+  end
+
+  def vnormalize
+    len = vlength
+    v = Vec.new(@x, @y, @z)
+    if len > 1.0e-17 then
+      v.x = v.x / len
+      v.y = v.y / len
+      v.z = v.z / len
+    end
+    v
+  end
+end
+
+
+class Sphere
+  def initialize(center, radius)
+    @center = center
+    @radius = radius
+  end
+
+  attr_reader :center, :radius
+
+  def intersect(ray, isect)
+    rs = ray.org.vsub(@center)
+    b = rs.vdot(ray.dir)
+    c = rs.vdot(rs) - (@radius * @radius)
+    d = b * b - c
+    if d > 0.0 then
+      t = - b - Math.sqrt(d)
+
+      if t > 0.0 and t < isect.t then
+        isect.t = t
+        isect.hit = true
+        isect.pl = Vec.new(ray.org.x + ray.dir.x * t,
+                          ray.org.y + ray.dir.y * t,
+                          ray.org.z + ray.dir.z * t)
+        n = isect.pl.vsub(@center)
+        isect.n = n.vnormalize
+      else
+        0.0
+      end
+    end
+    nil
+  end
+end
+
+class Plane
+  def initialize(p, n)
+    @p = p
+    @n = n
+  end
+
+  def intersect(ray, isect)
+    d = -@p.vdot(@n)
+    v = ray.dir.vdot(@n)
+    v0 = v
+    if v < 0.0 then
+      v0 = -v
+    end
+    if v0 < 1.0e-17 then
+      return
+    end
+
+    t = -(ray.org.vdot(@n) + d) / v
+
+    if t > 0.0 and t < isect.t then
+      isect.hit = true
+      isect.t = t
+      isect.n = @n
+      isect.pl = Vec.new(ray.org.x + t * ray.dir.x,
+                        ray.org.y + t * ray.dir.y,
+                        ray.org.z + t * ray.dir.z)
+    end
+    nil
+  end
+end
+
+class Ray
+  def initialize(org, dir)
+    @org = org
+    @dir = dir
+  end
+
+  attr_accessor :org, :dir
+end
+
+class Isect
+  def initialize
+    @t = 10000000.0
+    @hit = false
+    @pl = Vec.new(0.0, 0.0, 0.0)
+    @n = Vec.new(0.0, 0.0, 0.0)
+  end
+
+  attr_accessor :t, :hit, :pl, :n
+end
+
+def clamp(f)
+  i = f * 255.5
+  if i > 255.0 then
+    i = 255.0
+  end
+  if i < 0.0 then
+    i = 0.0
+  end
+  i.to_i
+end
+
+def otherBasis(basis, n)
+  basis[2] = Vec.new(n.x, n.y, n.z)
+  basis[1] = Vec.new(0.0, 0.0, 0.0)
+
+  if n.x < 0.6 and n.x > -0.6 then
+    basis[1].x = 1.0
+  elsif n.y < 0.6 and n.y > -0.6 then
+    basis[1].y = 1.0
+  elsif n.z < 0.6 and n.z > -0.6 then
+    basis[1].z = 1.0
+  else
+    basis[1].x = 1.0
+  end
+
+  basis[0] = basis[1].vcross(basis[2])
+  basis[0] = basis[0].vnormalize
+
+  basis[1] = basis[2].vcross(basis[0])
+  basis[1] = basis[1].vnormalize
+end
+
+class Scene
+  def initialize
+    @spheres = Array.new
+    @spheres[0] = Sphere.new(Vec.new(-2.0, 0.0, -3.5), 0.5)
+    @spheres[1] = Sphere.new(Vec.new(-0.5, 0.0, -3.0), 0.5)
+    @spheres[2] = Sphere.new(Vec.new(1.0, 0.0, -2.2), 0.5)
+    @plane = Plane.new(Vec.new(0.0, -0.5, 0.0), Vec.new(0.0, 1.0, 0.0))
+  end
+
+  def ambient_occlusion(isect)
+    basis = Array.new
+    otherBasis(basis, isect.n)
+
+    ntheta    = NAO_SAMPLES
+    nphi      = NAO_SAMPLES
+    eps       = 0.0001
+    occlusion = 0.0
+
+    p0 = Vec.new(isect.pl.x + eps * isect.n.x,
+                isect.pl.y + eps * isect.n.y,
+                isect.pl.z + eps * isect.n.z)
+    nphi.times do |j|
+      ntheta.times do |i|
+        r = rand
+        phi = 2.0 * 3.14159265 * rand
+        x = Math.cos(phi) * Math.sqrt(1.0 - r)
+        y = Math.sin(phi) * Math.sqrt(1.0 - r)
+        z = Math.sqrt(r)
+
+        rx = x * basis[0].x + y * basis[1].x + z * basis[2].x
+        ry = x * basis[0].y + y * basis[1].y + z * basis[2].y
+        rz = x * basis[0].z + y * basis[1].z + z * basis[2].z
+
+        raydir = Vec.new(rx, ry, rz)
+        ray = Ray.new(p0, raydir)
+
+        occisect = Isect.new
+        @spheres[0].intersect(ray, occisect)
+        @spheres[1].intersect(ray, occisect)
+        @spheres[2].intersect(ray, occisect)
+        @plane.intersect(ray, occisect)
+        if occisect.hit then
+          occlusion = occlusion + 1.0
+        else
+          0.0
+        end
+      end
+    end
+
+    occlusion = (ntheta.to_f * nphi.to_f - occlusion) / (ntheta.to_f * nphi.to_f)
+
+    Vec.new(occlusion, occlusion, occlusion)
+  end
+
+  def render(w, h, nsubsamples)
+    cnt = 0
+    nsf = nsubsamples.to_f
+    h.times do |y|
+      w.times do |x|
+        rad = Vec.new(0.0, 0.0, 0.0)
+
+        # Subsampling
+        nsubsamples.times do |v|
+          nsubsamples.times do |u|
+
+            cnt = cnt + 1
+            wf = w.to_f
+            hf = h.to_f
+            xf = x.to_f
+            yf = y.to_f
+            uf = u.to_f
+            vf = v.to_f
+
+            px = (xf + (uf / nsf) - (wf / 2.0)) / (wf / 2.0)
+            py = -(yf + (vf / nsf) - (hf / 2.0)) / (hf / 2.0)
+
+            eye = Vec.new(px, py, -1.0).vnormalize
+
+            ray = Ray.new(Vec.new(0.0, 0.0, 0.0), eye)
+
+            isect = Isect.new
+            @spheres[0].intersect(ray, isect)
+            @spheres[1].intersect(ray, isect)
+            @spheres[2].intersect(ray, isect)
+            @plane.intersect(ray, isect)
+            if isect.hit then
+              col = ambient_occlusion(isect)
+              rad.x = rad.x + col.x
+              rad.y = rad.y + col.y
+              rad.z = rad.z + col.z
+            end
+          end
+        end
+
+        r = rad.x / (nsf * nsf)
+        g = rad.y / (nsf * nsf)
+        b = rad.z / (nsf * nsf)
+        printf("%c", clamp(r))
+        printf("%c", clamp(g))
+        printf("%c", clamp(b))
+      end
+      nil
+    end
+
+    nil
+  end
+end
+
+alias printf_orig printf
+def printf *args
+  # $fp.printf(*args)
+end
+
+# File.open("ao.ppm", "w") do |fp|
+  # $fp = fp
+  printf("P6\n")
+  printf("%d %d\n", IMAGE_WIDTH, IMAGE_HEIGHT)
+  printf("255\n")
+  Scene.new.render(IMAGE_WIDTH, IMAGE_HEIGHT, NSUBSAMPLES)
+# end
+
+undef printf
+alias printf printf_orig
diff --git a/benchmark/app_erb.yml b/benchmark/app_erb.yml
new file mode 100644
index 0000000000..31e29b7644
--- /dev/null
+++ b/benchmark/app_erb.yml
@@ -0,0 +1,23 @@
+#
+# Create many HTML strings with ERB.
+#
+prelude: |
+  require 'erb'
+
+  data = <<erb
+  <html>
+    <head> <%= title %> </head>
+    <body>
+      <h1> <%= title %> </h1>
+      <p>
+        <%= content %>
+      </p>
+    </body>
+  </html>
+  erb
+
+  title = "hello world!"
+  content = "hello world!\n" * 10
+benchmark:
+  app_erb: ERB.new(data).result(binding)
+loop_count: 15000
diff --git a/benchmark/bm_app_factorial.rb b/benchmark/app_factorial.rb