Use the syntax of a property addition as a hint for controlling the fast-mode vs. dictionary mode h…

src/objects-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 1593 matching lines @@
     offset += kPointerSize;
   }
 }
 
 
 bool JSObject::HasFastProperties() {
   return !properties()->IsDictionary();
 }
 
 
-bool JSObject::TooManyFastProperties(int properties) {
+bool JSObject::TooManyFastProperties(int properties,
+                                     JSObject::StoreFromKeyed store_mode) {
   // Allow extra fast properties if the object has more than
   // kFastPropertiesSoftLimit in-object properties. When this is the case,
   // it is very unlikely that the object is being used as a dictionary
   // and there is a good chance that allowing more map transitions
   // will be worth it.
   int inobject = map()->inobject_properties();
 
   int limit;
-  if (map()->used_for_prototype()) {
+  if (store_mode == CERTAINLY_NOT_STORE_FROM_KEYED ||
+      map()->used_for_prototype()) {
     limit = Max(inobject, kMaxFastProperties);
   } else {
     limit = Max(inobject, kFastPropertiesSoftLimit);
   }
   return properties > limit;
 }
 
 
 void Struct::InitializeBody(int object_size) {
   Object* value = GetHeap()->undefined_value();
@@ skipping 3451 matching lines @@
 #undef WRITE_UINT32_FIELD
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_