Avoid duplication of a hidden & inherited prototype's properties.

src/runtime.cc

 // Copyright 2012 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 5708 matching lines @@
       GetKeysInFixedArrayFor(object, INCLUDE_PROTOS, &threw);
   if (threw) return Failure::Exception();
 
   // Test again, since cache may have been built by preceding call.
   if (object->IsSimpleEnum()) return object->map();
 
   return *content;
 }
 
 
+// Returns true if inherited accessors have been copied down
+// to obj from proto's function template.
+static bool IsInheritedApiFunctionOf(JSObject *obj, Object *proto) {
+  Object *constructor = HeapObject::cast(proto)->map()->constructor();
+  if (!constructor->IsJSFunction()) {

[jochen (gone - plz use gerrit), 2013/12/17 15:00:53]

nit. v8 style is if (...) return false; (in one line). if it doesn't fit in one
line, but the body is just one line, no need for { }

+    return false;
+  }
+  JSFunction *constructor_fun = JSFunction::cast(constructor);
+  if (!constructor_fun->shared()->IsApiFunction()) {
+    return false;
+  }
+  return constructor_fun->shared()->

[jochen (gone - plz use gerrit), 2013/12/17 15:00:53]

nit the -> should go on the next line

+      get_api_func_data()->IsTemplateFor(obj);
+}
+
+
 // Find the length of the prototype chain that is to to handled as one. If a
 // prototype object is hidden it is to be viewed as part of the the object it
 // is prototype for.
 static int LocalPrototypeChainLength(JSObject* obj) {
   int count = 1;
   Object* proto = obj->GetPrototype();
   while (proto->IsJSObject() &&
-         JSObject::cast(proto)->map()->is_hidden_prototype()) {
+         JSObject::cast(proto)->map()->is_hidden_prototype() &&
+         !IsInheritedApiFunctionOf(obj, proto)) {
     count++;
     proto = JSObject::cast(proto)->GetPrototype();
   }
   return count;
 }
 
 
 // Return the names of the local named properties.
 // args[0]: object
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetLocalPropertyNames) {
@@ skipping 9156 matching lines @@
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
                                        "Runtime::PerformGC");
   }
 }
 
 
 } }  // namespace v8::internal