[builtins] TurboFan version of Array.prototype.forEach including fast path for FAST_ELEMENTS

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index da25d060ff14446258a2760ec2dc8b9dc2379130..95e18098b19e89def682e8f51cd6fd63763c8166 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -217,6 +217,8 @@ class Genesis BASE_EMBEDDED {
   HARMONY_SHIPPING(DECLARE_FEATURE_INITIALIZATION)
 #undef DECLARE_FEATURE_INITIALIZATION
 
+  void InitializeGlobal_enable_fast_array_builtins();
+
   Handle<JSFunction> InstallArrayBuffer(Handle<JSObject> target,
                                         const char* name, Builtins::Name call,
                                         BuiltinFunctionId id);
@@ -2911,6 +2913,8 @@ void Genesis::InitializeExperimentalGlobal() {
   HARMONY_STAGED(FEATURE_INITIALIZE_GLOBAL)
   HARMONY_SHIPPING(FEATURE_INITIALIZE_GLOBAL)
 #undef FEATURE_INITIALIZE_GLOBAL
+
+  InitializeGlobal_enable_fast_array_builtins();
 }
 
 
@@ -3540,6 +3544,22 @@ void InstallPublicSymbol(Factory* factory, Handle<Context> native_context,
   JSObject::AddProperty(symbol, name_string, value, attributes);
 }
 
+void Genesis::InitializeGlobal_enable_fast_array_builtins() {
+  if (!FLAG_enable_fast_array_builtins) return;
+
+  Handle<JSGlobalObject> global(native_context()->global_object());
+  Isolate* isolate = global->GetIsolate();
+  Factory* factory = isolate->factory();
+
+  Handle<JSObject> utils =
+      Handle<JSObject>::cast(isolate->natives_utils_object());

[Yang, 2017/02/03 10:20:25]

Alternatively, you could just get global.Array.prototype.forEach, and won't have
to touch the utils object at all.

[danno, 2017/02/03 12:46:55]

Done.

+  LookupIterator it(utils,
+                    factory->NewStringFromAsciiChecked("ForEachFunction"),
+                    LookupIterator::OWN_SKIP_INTERCEPTOR);
+  Handle<Object> for_each_function = Object::GetProperty(&it).ToHandleChecked();
+  Handle<JSFunction>::cast(for_each_function)
+      ->set_code(isolate->builtins()->builtin(Builtins::kArrayForEach));
+}
 
 void Genesis::InitializeGlobal_harmony_sharedarraybuffer() {
   if (!FLAG_harmony_sharedarraybuffer) return;