- Optimized JSArray allocation in runtime system by using NewJSArrayWithEleme...

src/handles.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * 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
@@ skipping 373 matching lines @@
           content = AddKeysFromJSArray(content, v8::Utils::OpenHandle(*result));
       }
     }
   }
   return content;
 }
 
 
 Handle<JSArray> GetKeysFor(Handle<JSObject> object) {
   Counters::for_in.Increment();
-
-  Handle<FixedArray> content = GetKeysInFixedArrayFor(object);
-
-  // Allocate the JSArray with the result.
-  Handle<JSArray> obj = Factory::NewJSArray(content->length());
-  Handle<JSArray>::cast(obj)->SetContent(*content);
-  return Handle<JSArray>::cast(obj);
+  Handle<FixedArray> elements = GetKeysInFixedArrayFor(object);
+  return Factory::NewJSArrayWithElements(elements);
 }
 
 
 Handle<FixedArray> GetEnumPropertyKeys(Handle<JSObject> object) {
   int index = 0;
   if (object->HasFastProperties()) {
     if (object->map()->instance_descriptors()->HasEnumCache()) {
       Counters::enum_cache_hits.Increment();
       DescriptorArray* desc = object->map()->instance_descriptors();
       return Handle<FixedArray>(FixedArray::cast(desc->GetEnumCache()));
@@ skipping 138 matching lines @@
                Handle<Context> security_context) {
   Handle<FixedArray> arr = Factory::NewFixedArray(4);
   arr->set(0, Smi::FromInt(index));
   arr->set(1, *compile_context);  // Compile in this context
   arr->set(2, *function_context);  // Set function context to this
   arr->set(3, *security_context);  // Receiver for call
   fun->shared()->set_lazy_load_data(*arr);
 }
 
 } }  // namespace v8::internal