Reapplying r5147 (caching maps for slow case objects)....

src/ic-inl.h

 // 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 90 matching lines @@
   if (holder != object &&
       !object->HasFastProperties() &&
       !object->IsJSGlobalProxy() &&
       !object->IsJSGlobalObject()) {
     return PROTOTYPE_MAP;
   }
   return OWN_MAP;
 }
 
 
-Map* IC::GetCodeCacheMap(Object* object, InlineCacheHolderFlag holder) {
+JSObject* IC::GetCodeCacheHolder(Object* object, InlineCacheHolderFlag holder) {
   Object* map_owner = (holder == OWN_MAP ? object : object->GetPrototype());
   ASSERT(map_owner->IsJSObject());
-  return JSObject::cast(map_owner)->map();
+  return JSObject::cast(map_owner);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_IC_INL_H_