Fastpath some spread-call desugaring.

src/bootstrapper.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/bootstrapper.h"
 
 #include "src/accessors.h"
 #include "src/api-natives.h"
 #include "src/base/ieee754.h"
 #include "src/code-stubs.h"
@@ skipping 2412 matching lines @@
     SimpleInstallFunction(reflect, factory->ownKeys_string(),
                           Builtins::kReflectOwnKeys, 1, true);
     SimpleInstallFunction(reflect, factory->preventExtensions_string(),
                           Builtins::kReflectPreventExtensions, 1, true);
     SimpleInstallFunction(reflect, factory->set_string(), Builtins::kReflectSet,
                           3, false);
     SimpleInstallFunction(reflect, factory->setPrototypeOf_string(),
                           Builtins::kReflectSetPrototypeOf, 2, true);
   }
 
+  {  // --- S P R E A D
+    Handle<JSObject> spread =
+        factory->NewJSObject(isolate->object_function(), TENURED);
+
+    Handle<JSFunction> apply_prepare = SimpleInstallFunction(
+        spread, factory->NewStringFromAsciiChecked("SpreadIterablePrepare"),
+        Builtins::kSpreadIterablePrepare, 1, false);

[Yang, 2016/11/08 14:08:41]

Why do we need this? I think what you want is to call a runtime function. See
src/runtime/runtime.h

[petermarshall, 2016/11/10 12:19:20]

Yep I've moved it to a runtime function

+    native_context()->set_spread_iterable_prepare(*apply_prepare);
+  }
+
   {  // --- B o u n d F u n c t i o n
     Handle<Map> map =
         factory->NewMap(JS_BOUND_FUNCTION_TYPE, JSBoundFunction::kSize);
     map->set_is_callable();
     Map::SetPrototype(map, empty_function);
 
     PropertyAttributes roc_attribs =
         static_cast<PropertyAttributes>(DONT_ENUM | READ_ONLY);
     Map::EnsureDescriptorSlack(map, 2);
 
@@ skipping 1029 matching lines @@
         InstallInternalArray(utils, "InternalArray", FAST_HOLEY_ELEMENTS);
     native_context()->set_internal_array_function(*array_function);
     InstallInternalArray(utils, "InternalPackedArray", FAST_ELEMENTS);
   }
 
   // Run the rest of the native scripts.
   while (builtin_index < Natives::GetBuiltinsCount()) {
     if (!Bootstrapper::CompileBuiltin(isolate(), builtin_index++)) return false;
   }
 
+  // Store the initial array iterator on the native context.
+  {
+    Handle<JSFunction> array_constructor(native_context()->array_function());
+    Handle<JSObject> array_prototype(
+        JSObject::cast(array_constructor->instance_prototype()));
+
+    Handle<Object> iterator_func =
+        Object::GetProperty(array_prototype, factory()->iterator_symbol())
+            .ToHandleChecked();
+    DCHECK(iterator_func->IsJSFunction());
+    native_context()->set_initial_array_iterator(

[Yang, 2016/11/08 14:08:41]

Isn't this the same thing as native_context()->array_values_iterator()?

[petermarshall, 2016/11/10 12:19:20]

Removed this anyway - no longer needed

+        JSObject::cast(*iterator_func));
+  }
+
   if (!CallUtilsFunction(isolate(), "PostNatives")) return false;
   auto fast_template_instantiations_cache = isolate()->factory()->NewFixedArray(
       TemplateInfo::kFastTemplateInstantiationsCacheSize);
   native_context()->set_fast_template_instantiations_cache(
       *fast_template_instantiations_cache);
 
   auto slow_template_instantiations_cache = UnseededNumberDictionary::New(
       isolate(), ApiNatives::kInitialFunctionCacheSize);
   native_context()->set_slow_template_instantiations_cache(
       *slow_template_instantiations_cache);
@@ skipping 1051 matching lines @@
 }
 
 
 // Called when the top-level V8 mutex is destroyed.
 void Bootstrapper::FreeThreadResources() {
   DCHECK(!IsActive());
 }
 
 }  // namespace internal
 }  // namespace v8