Use a BOP for Hash#default

On a hash miss we need to call default if it is redefined in order to
return the default value to be used. Previously we checked this with
rb_method_basic_definition_p, which avoids the method call but requires
a method lookup.

This commit replaces the previous check with BASIC_OP_UNREDEFINED_P and
a new BOP_DEFAULT. We still need to fall back to
rb_method_basic_definition_p when called on a subclasss of hash.

    |                |compare-ruby|built-ruby|
    |:---------------|-----------:|---------:|
    |hash_aref_miss  |       2.692|     3.531|
    |                |           -|     1.31x|

Co-authored-by: Daniel Colson <danieljamescolson@gmail.com>
Co-authored-by: "Ian C. Anderson" <ian@iancanderson.com>
Co-authored-by: Jack McCracken <me@jackmc.xyz>

5 files changed, 42 insertions, 22 deletions

diff --git a/defs/id.def b/defs/id.def
index a3a383f532..ebf00506ea 100644
--- a/defs/id.def
+++ b/defs/id.def
@@ -76,6 +76,7 @@ firstline, predefined = __LINE__+1, %[\
   "/*NULL*/"                                            NULL
   empty?
   eql?
+  default
   respond_to?                                           Respond_to
   respond_to_missing?                                   Respond_to_missing
   <IFUNC>
diff --git a/hash.c b/hash.c
index a577e77985..1923c63eb3 100644
--- a/hash.c
+++ b/hash.c
@@ -28,6 +28,7 @@
 #include "internal.h"
 #include "internal/array.h"
 #include "internal/bignum.h"
+#include "internal/basic_operators.h"
 #include "internal/class.h"
 #include "internal/cont.h"
 #include "internal/error.h"
@@ -93,9 +94,11 @@ rb_hash_freeze(VALUE hash)
 VALUE rb_cHash;
 
 static VALUE envtbl;
-static ID id_hash, id_default, id_flatten_bang;
+static ID id_hash, id_flatten_bang;
 static ID id_hash_iter_lev;
 
+#define id_default idDefault
+
 VALUE
 rb_hash_set_ifnone(VALUE hash, VALUE ifnone)
 {
@@ -2070,10 +2073,22 @@ call_default_proc(VALUE proc, VALUE hash, VALUE key)
     return rb_proc_call_with_block(proc, 2, args, Qnil);
 }
 
+static bool
+rb_hash_default_unredefined(VALUE hash)
+{
+    VALUE klass = RBASIC_CLASS(hash);
+    if (LIKELY(klass == rb_cHash)) {
+        return !!BASIC_OP_UNREDEFINED_P(BOP_DEFAULT, HASH_REDEFINED_OP_FLAG);
+    }
+    else {
+        return LIKELY(rb_method_basic_definition_p(klass, id_default));
+    }
+}
+
 VALUE
 rb_hash_default_value(VALUE hash, VALUE key)
 {
-    if (LIKELY(rb_method_basic_definition_p(CLASS_OF(hash), id_default))) {
+    if (LIKELY(rb_hash_default_unredefined(hash))) {
         VALUE ifnone = RHASH_IFNONE(hash);
         if (!FL_TEST(hash, RHASH_PROC_DEFAULT)) return ifnone;
         if (UNDEF_P(key)) return Qnil;
@@ -7164,7 +7179,6 @@ void
 Init_Hash(void)
 {
     id_hash = rb_intern_const("hash");
-    id_default = rb_intern_const("default");
     id_flatten_bang = rb_intern_const("flatten!");
     id_hash_iter_lev = rb_make_internal_id();
 
diff --git a/internal/basic_operators.h b/internal/basic_operators.h
index aa63c455b7..2cd9f50073 100644
--- a/internal/basic_operators.h
+++ b/internal/basic_operators.h
@@ -35,6 +35,7 @@ enum ruby_basic_operators {
     BOP_AND,
     BOP_OR,
     BOP_CMP,
+    BOP_DEFAULT,
 
     BOP_LAST_
 };
diff --git a/vm.c b/vm.c
index 8daed5d474..2821f58adb 100644
--- a/vm.c
+++ b/vm.c
@@ -2054,6 +2054,7 @@ vm_init_redefined_flag(void)
     OP(Or, OR), (C(Integer));
     OP(NilP, NIL_P), (C(NilClass));
     OP(Cmp, CMP), (C(Integer), C(Float), C(String));
+    OP(Default, DEFAULT), (C(Hash));
 #undef C
 #undef OP
 }
diff --git a/yjit/src/cruby_bindings.inc.rs b/yjit/src/cruby_bindings.inc.rs
index f20dc04966..759c4d0ec7 100644
--- a/yjit/src/cruby_bindings.inc.rs
+++ b/yjit/src/cruby_bindings.inc.rs
@@ -418,21 +418,22 @@ pub const tNUMPARAM_6: ruby_method_ids = 234;
 pub const tNUMPARAM_7: ruby_method_ids = 235;
 pub const tNUMPARAM_8: ruby_method_ids = 236;
 pub const tNUMPARAM_9: ruby_method_ids = 237;
-pub const tTOKEN_LOCAL_END: ruby_method_ids = 238;
-pub const tTOKEN_INSTANCE_BEGIN: ruby_method_ids = 237;
-pub const tTOKEN_INSTANCE_END: ruby_method_ids = 238;
-pub const tTOKEN_GLOBAL_BEGIN: ruby_method_ids = 237;
-pub const tLASTLINE: ruby_method_ids = 238;
-pub const tBACKREF: ruby_method_ids = 239;
-pub const tERROR_INFO: ruby_method_ids = 240;
-pub const tTOKEN_GLOBAL_END: ruby_method_ids = 241;
-pub const tTOKEN_CONST_BEGIN: ruby_method_ids = 240;
-pub const tTOKEN_CONST_END: ruby_method_ids = 241;
-pub const tTOKEN_CLASS_BEGIN: ruby_method_ids = 240;
-pub const tTOKEN_CLASS_END: ruby_method_ids = 241;
-pub const tTOKEN_ATTRSET_BEGIN: ruby_method_ids = 240;
-pub const tTOKEN_ATTRSET_END: ruby_method_ids = 241;
-pub const tNEXT_ID: ruby_method_ids = 241;
+pub const tDefault: ruby_method_ids = 238;
+pub const tTOKEN_LOCAL_END: ruby_method_ids = 239;
+pub const tTOKEN_INSTANCE_BEGIN: ruby_method_ids = 238;
+pub const tTOKEN_INSTANCE_END: ruby_method_ids = 239;
+pub const tTOKEN_GLOBAL_BEGIN: ruby_method_ids = 238;
+pub const tLASTLINE: ruby_method_ids = 239;
+pub const tBACKREF: ruby_method_ids = 240;
+pub const tERROR_INFO: ruby_method_ids = 241;
+pub const tTOKEN_GLOBAL_END: ruby_method_ids = 242;
+pub const tTOKEN_CONST_BEGIN: ruby_method_ids = 241;
+pub const tTOKEN_CONST_END: ruby_method_ids = 242;
+pub const tTOKEN_CLASS_BEGIN: ruby_method_ids = 241;
+pub const tTOKEN_CLASS_END: ruby_method_ids = 242;
+pub const tTOKEN_ATTRSET_BEGIN: ruby_method_ids = 241;
+pub const tTOKEN_ATTRSET_END: ruby_method_ids = 242;
+pub const tNEXT_ID: ruby_method_ids = 242;
 pub const idMax: ruby_method_ids = 2721;
 pub const idMin: ruby_method_ids = 2737;
 pub const idFreeze: ruby_method_ids = 2753;
@@ -501,9 +502,10 @@ pub const idNUMPARAM_6: ruby_method_ids = 3745;
 pub const idNUMPARAM_7: ruby_method_ids = 3761;
 pub const idNUMPARAM_8: ruby_method_ids = 3777;
 pub const idNUMPARAM_9: ruby_method_ids = 3793;
-pub const idLASTLINE: ruby_method_ids = 3815;
-pub const idBACKREF: ruby_method_ids = 3831;
-pub const idERROR_INFO: ruby_method_ids = 3847;
+pub const idDefault: ruby_method_ids = 3809;
+pub const idLASTLINE: ruby_method_ids = 3831;
+pub const idBACKREF: ruby_method_ids = 3847;
+pub const idERROR_INFO: ruby_method_ids = 3863;
 pub const tLAST_OP_ID: ruby_method_ids = 169;
 pub const idLAST_OP_ID: ruby_method_ids = 10;
 pub type ruby_method_ids = u32;
@@ -537,7 +539,8 @@ pub const BOP_CALL: ruby_basic_operators = 26;
 pub const BOP_AND: ruby_basic_operators = 27;
 pub const BOP_OR: ruby_basic_operators = 28;
 pub const BOP_CMP: ruby_basic_operators = 29;
-pub const BOP_LAST_: ruby_basic_operators = 30;
+pub const BOP_DEFAULT: ruby_basic_operators = 30;
+pub const BOP_LAST_: ruby_basic_operators = 31;
 pub type ruby_basic_operators = u32;
 pub type rb_serial_t = ::std::os::raw::c_ulonglong;
 pub const imemo_env: imemo_type = 0;