Always store stubs on the JSObject receiver, even when in slow mode.

src/ic-inl.h

 // 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 84 matching lines @@
     heap->mark_compact_collector()->RecordCodeTargetPatch(address, target);
   } else {
     heap->incremental_marking()->RecordCodeTargetPatch(address, target);
   }
   PostPatching(address, target, old_target);
 }
 
 
 InlineCacheHolderFlag IC::GetCodeCacheForObject(Object* object,
                                                 JSObject* holder) {
-  if (object->IsJSObject()) {
-    return GetCodeCacheForObject(JSObject::cast(object), holder);
-  }
+  if (object->IsJSObject()) return OWN_MAP;
+
   // If the object is a value, we use the prototype map for the cache.
   ASSERT(object->IsString() || object->IsSymbol() ||
          object->IsNumber() || object->IsBoolean());
   return PROTOTYPE_MAP;
 }
 
 
-InlineCacheHolderFlag IC::GetCodeCacheForObject(JSObject* object,
-                                                JSObject* holder) {
-  // Fast-properties and global objects store stubs in their own maps.
-  // Slow properties objects use prototype's map (unless the property is its own
-  // when holder == object). It works because slow properties objects having
-  // the same prototype (or a prototype with the same map) and not having
-  // the property are interchangeable for such a stub.
-  if (holder != object &&
-      !object->HasFastProperties() &&
-      !object->IsJSGlobalProxy() &&
-      !object->IsJSGlobalObject()) {
-    return PROTOTYPE_MAP;
-  }
-  return OWN_MAP;
-}
-
-
 JSObject* IC::GetCodeCacheHolder(Isolate* isolate,
                                  Object* object,
                                  InlineCacheHolderFlag holder) {
   Object* map_owner =
       holder == OWN_MAP ? object : object->GetPrototype(isolate);
   ASSERT(map_owner->IsJSObject());
   return JSObject::cast(map_owner);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_IC_INL_H_