Refactor ujit_examples.h generator. Remove dwarfdump dependency

5 files changed, 215 insertions, 62 deletions

diff --git a/tool/ruby_vm/models/instructions.rb b/tool/ruby_vm/models/instructions.rb
index 83dff9c5b0..065ac7dbf2 100644
--- a/tool/ruby_vm/models/instructions.rb
+++ b/tool/ruby_vm/models/instructions.rb
@@ -13,71 +13,12 @@
 require_relative 'bare_instructions'
 require_relative 'operands_unifications'
 require_relative 'instructions_unifications'
-
-class RubyVM::UJITExampleInstructions
-  include RubyVM::CEscape
-
-  attr_reader :name
-
-  def initialize name
-    @name = name
-  end
-
-  def pretty_name
-    return sprintf "%s(...)(...)(...)", @name
-  end
-
-  def jump_destination
-    return @orig.name
-  end
-
-  def bin
-    return sprintf "BIN(%s)", @name
-  end
-
-  def width
-    1
-  end
-
-  def operands_info
-    ""
-  end
-
-  def rets
-    return ['...']
-  end
-
-  def pops
-    return ['...']
-  end
-
-  def attributes
-    return []
-  end
-
-  def has_attribute? *;
-    return false
-  end
-
-  def handles_sp?
-    false
-  end
-
-  def always_leaf?
-    false
-  end
-
-  @all_examples = [new('ujit_call_example')]
-
-  def self.to_a
-    @all_examples
-  end
-end
+require_relative 'micro_jit'
 
 RubyVM::Instructions = RubyVM::BareInstructions.to_a + \
                        RubyVM::OperandsUnifications.to_a + \
                        RubyVM::InstructionsUnifications.to_a + \
-                       RubyVM::UJITExampleInstructions.to_a
+                       RubyVM::MicroJIT::ExampleInstructions.to_a
 
                 
 
diff --git a/tool/ruby_vm/models/micro_jit.rb b/tool/ruby_vm/models/micro_jit.rb
new file mode 100644
index 0000000000..eee829a2e6
--- /dev/null
+++ b/tool/ruby_vm/models/micro_jit.rb
@@ -0,0 +1,125 @@
+#! /your/favourite/path/to/ruby
+# -*- Ruby -*-
+# -*- frozen_string_literal: true; -*-
+# -*- warn_indent: true; -*-
+#
+# Copyright (c) 2020 Wu, Alan.  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.
+
+module RubyVM::MicroJIT
+  class << self
+    def get_fileoff
+      # use the load command to figure out the offset to the start of the content of vm.o
+      `otool -l vm.o`.each_line do |line|
+        if (fileoff = line[/fileoff (\d+)/, 1])
+          p [__method__, line] if $DEBUG
+          return fileoff.to_i
+        end
+      end
+      raise
+    end
+
+    def get_symbol_offset(symbol)
+      `nm vm.o`.each_line do |line|
+        if (offset = line[Regexp.compile('(\h+).+' + Regexp.escape(symbol) + '\Z'), 1])
+          p [__method__, line] if $DEBUG
+          return Integer(offset, 16)
+        end
+      end
+      raise
+    end
+
+    def readint8b(offset)
+      bytes = IO.binread('vm.o', 8, offset)
+      bytes.unpack('q').first #  this is native endian but we want little endian. it's fine if the host moachine is x86
+    end
+
+    def disassemble(offset)
+      command = "objdump --x86-asm-syntax=intel --start-address=#{offset} --stop-address=#{offset+50} -d vm.o"
+      puts "Running: #{command}"
+      puts "feel free to verify with --reloc"
+      disassembly = `#{command}`
+      instructions = []
+      puts disassembly if $DEBUG
+      disassembly.each_line do |line|
+        line = line.strip
+        match_data = /\h+: ((?:\h\h\s?)+)\s+(\w+)/.match(line)
+        if match_data
+          bytes = match_data[1]
+          mnemonic = match_data[2]
+          instructions << [bytes, mnemonic, line]
+          break if mnemonic == 'jmp'
+        elsif !instructions.empty?
+          p line
+          raise "expected a continuous sequence of disassembly lines"
+        end
+      end
+
+      jmp_idx = instructions.find_index { |_, mnemonic, _| mnemonic == 'jmp' }
+      raise 'failed to find jmp' unless jmp_idx
+      raise 'generated code for example too long' unless jmp_idx < 10
+      handler_instructions = instructions[(0..jmp_idx)]
+
+      puts "Disassembly for the example handler:"
+      puts handler_instructions.map {|_, _, line| line}
+
+
+      raise 'rip reference in example makes copying unsafe' if handler_instructions.any? { |_, _, full_line| full_line.downcase.include?('rip') }
+      acceptable_mnemonics = %w(mov jmp lea call)
+      unrecognized = nil
+      handler_instructions.each { |i| unrecognized = i unless acceptable_mnemonics.include?(i[1]) }
+      raise "found an unrecognized \"#{unrecognized[1]}\" instruction in the example. List of recognized instructions: #{acceptable_mnemonics.join(', ')}" if unrecognized
+      raise 'found multiple jmp instructions' if handler_instructions.count { |_, mnemonic, _| mnemonic == 'jmp' } > 1
+      raise "the jmp instruction seems to be relative which isn't copiable" if instructions[jmp_idx][0].split.size > 4
+      raise 'found multiple call instructions' if handler_instructions.count { |_, mnemonic, _| mnemonic == 'call' } > 1
+      call_idx = handler_instructions.find_index { |_, mnemonic, _| mnemonic == 'call' }
+
+
+      @pre_call_bytes = []
+      @post_call_bytes = []
+
+      handler_instructions.take(call_idx).each do |bytes, mnemonic, _|
+        @pre_call_bytes += bytes.split
+      end
+
+      handler_instructions[call_idx + 1, handler_instructions.size].each do |bytes, _, _|
+        @post_call_bytes += bytes.split
+      end
+    end
+
+    def scrape
+      instruction_id = RubyVM::Instructions.find_index { |insn| insn.name == 'ujit_call_example' }
+      fileoff = get_fileoff
+      tc_table_offset = get_symbol_offset('vm_exec_core.insns_address_table')
+      vm_exec_core_offset = get_symbol_offset('vm_exec_core')
+      p instruction_id if $DEBUG
+      p fileoff if $DEBUG
+      p tc_table_offset.to_s(16) if $DEBUG
+      offset_to_insn_in_tc_table = fileoff + tc_table_offset + 8 * instruction_id
+      p offset_to_insn_in_tc_table if $DEBUG
+      offset_to_handler_code_from_vm_exec_core = readint8b(offset_to_insn_in_tc_table)
+      p offset_to_handler_code_from_vm_exec_core if $DEBUG
+      disassemble(vm_exec_core_offset + offset_to_handler_code_from_vm_exec_core)
+    end
+
+    def comma_separated_hex_string(nums)
+      nums.map{ |byte| '0x'+byte}.join(', ')
+    end
+
+    def pre_call_bytes
+      scrape unless @pre_call_bytes
+      comma_separated_hex_string(@pre_call_bytes)
+    end
+
+    def post_call_bytes
+      scrape unless @post_call_bytes
+      comma_separated_hex_string(@post_call_bytes)
+    end
+  end
+end
+
+require_relative 'micro_jit/example_instructions'
diff --git a/tool/ruby_vm/models/micro_jit/example_instructions.rb b/tool/ruby_vm/models/micro_jit/example_instructions.rb
new file mode 100644
index 0000000000..5117d1c519
--- /dev/null
+++ b/tool/ruby_vm/models/micro_jit/example_instructions.rb
@@ -0,0 +1,71 @@
+#! /your/favourite/path/to/ruby
+# -*- Ruby -*-
+# -*- frozen_string_literal: true; -*-
+# -*- warn_indent: true; -*-
+#
+# Copyright (c) 2020 Wu, Alan.  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.
+
+class RubyVM::MicroJIT::ExampleInstructions
+  include RubyVM::CEscape
+
+  attr_reader :name
+
+  def initialize name
+    @name = name
+  end
+
+  def pretty_name
+    return sprintf "%s(...)(...)(...)", @name
+  end
+
+  def jump_destination
+    return @orig.name
+  end
+
+  def bin
+    return sprintf "BIN(%s)", @name
+  end
+
+  def width
+    1
+  end
+
+  def operands_info
+    ""
+  end
+
+  def rets
+    return ['...']
+  end
+
+  def pops
+    return ['...']
+  end
+
+  def attributes
+    return []
+  end
+
+  def has_attribute? *;
+    return false
+  end
+
+  def handles_sp?
+    false
+  end
+
+  def always_leaf?
+    false
+  end
+
+  @all_examples = [new('ujit_call_example')]
+
+  def self.to_a
+    @all_examples
+  end
+end
diff --git a/tool/ruby_vm/views/ujit_examples.inc.erb b/tool/ruby_vm/views/ujit_examples.inc.erb
new file mode 100644
index 0000000000..a301c5ca74
--- /dev/null
+++ b/tool/ruby_vm/views/ujit_examples.inc.erb
@@ -0,0 +1,16 @@
+/* -*- C -*- */
+
+%# Copyright (c) 2020 Wu, Alan.  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.
+<%= render 'copyright' %>
+<%= render 'notice', locals: {
+    this_file: 'contains raw instruction bytes that helps MicroJIT generate code',
+    edit: __FILE__,
+} -%>
+
+static const uint8_t ujit_pre_call_bytes[] = { <%= RubyVM::MicroJIT.pre_call_bytes %> };
+static const uint8_t ujit_post_call_bytes[] = { <%= RubyVM::MicroJIT.post_call_bytes %> };
diff --git a/tool/ruby_vm/views/vm.inc.erb b/tool/ruby_vm/views/vm.inc.erb
index 7942a3ef87..3c7b602859 100644
--- a/tool/ruby_vm/views/vm.inc.erb
+++ b/tool/ruby_vm/views/vm.inc.erb
@@ -28,7 +28,7 @@
 % RubyVM::TraceInstructions.to_a.each do |insn|
 <%= render 'trace_instruction', locals: { insn: insn } -%>
 % end
-% RubyVM::UJITExampleInstructions.to_a.each do |insn|
+% RubyVM::MicroJIT::ExampleInstructions.to_a.each do |insn|
 INSN_ENTRY(<%= insn.name %>)
 {
     START_OF_ORIGINAL_INSN(<%= insn.name %>);