Reimplement SetProperty using the LookupIterator

src/objects-inl.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
@@ skipping 2060 matching lines @@
   }
 }
 
 
 bool JSObject::HasFastProperties() {
   ASSERT(properties()->IsDictionary() == map()->is_dictionary_map());
   return !properties()->IsDictionary();
 }
 
 
-bool JSObject::TooManyFastProperties(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.
-  Map* map = this->map();
-  if (map->unused_property_fields() != 0) return false;
-
-  int inobject = map->inobject_properties();
-
-  int limit;
-  if (store_mode == CERTAINLY_NOT_STORE_FROM_KEYED) {
-    limit = Max(inobject, kMaxFastProperties);
-  } else {
-    limit = Max(inobject, kFastPropertiesSoftLimit);
-  }
-  return properties()->length() > limit;
+bool Map::TooManyFastProperties(StoreFromKeyed store_mode) {
+  if (unused_property_fields() != 0) return false;
+  int minimum = store_mode == CERTAINLY_NOT_STORE_FROM_KEYED ? 128 : 12;
+  int limit = Max(minimum, inobject_properties());
+  int external = NumberOfFields() - inobject_properties();
+  return external > limit;
 }
 
 
 void Struct::InitializeBody(int object_size) {
   Object* value = GetHeap()->undefined_value();
   for (int offset = kHeaderSize; offset < object_size; offset += kPointerSize) {
     WRITE_FIELD(this, offset, value);
   }
 }
 
@@ skipping 5102 matching lines @@
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_