Reland "Enable Object.observe by default" again

src/objects.cc

 // Copyright 2013 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 2163 matching lines @@
     } else {
       // Normalize the object to prevent very large instance descriptors.
       // This eliminates unwanted N^2 allocation and lookup behavior.
       NormalizeProperties(object, CLEAR_INOBJECT_PROPERTIES, 0);
       AddSlowProperty(object, name, value, attributes);
     }
   } else {
     AddSlowProperty(object, name, value, attributes);
   }
 
-  if (FLAG_harmony_observation &&
-      object->map()->is_observed() &&
+  if (object->map()->is_observed() &&
       *name != isolate->heap()->hidden_string()) {
     Handle<Object> old_value = isolate->factory()->the_hole_value();
     EnqueueChangeRecord(object, "add", name, old_value);
   }
 
   return value;
 }
 
 
 void JSObject::EnqueueChangeRecord(Handle<JSObject> object,
@@ skipping 1877 matching lines @@
       Handle<Object> error = isolate->factory()->NewTypeError(
           "strict_read_only_property", HandleVector(args, ARRAY_SIZE(args)));
       isolate->Throw(*error);
       return Handle<Object>();
     } else {
       return value;
     }
   }
 
   Handle<Object> old_value = isolate->factory()->the_hole_value();
-  bool is_observed = FLAG_harmony_observation &&
-                     object->map()->is_observed() &&
+  bool is_observed = object->map()->is_observed() &&
                      *name != isolate->heap()->hidden_string();
   if (is_observed && lookup->IsDataProperty()) {
     old_value = Object::GetProperty(object, name);
   }
 
   // This is a real property that is not read-only, or it is a
   // transition or null descriptor and there are no setters in the prototypes.
   Handle<Object> result = value;
   switch (lookup->type()) {
     case NORMAL:
@@ skipping 101 matching lines @@
     object->map()->LookupTransition(*object, *name, &lookup);
     TransitionFlag flag = lookup.IsFound()
         ? OMIT_TRANSITION : INSERT_TRANSITION;
     // Neither properties nor transitions found.
     return AddProperty(object, name, value, attributes, SLOPPY,
         MAY_BE_STORE_FROM_KEYED, extensibility_check, value_type, mode, flag);
   }
 
   Handle<Object> old_value = isolate->factory()->the_hole_value();
   PropertyAttributes old_attributes = ABSENT;
-  bool is_observed = FLAG_harmony_observation &&
-                     object->map()->is_observed() &&
+  bool is_observed = object->map()->is_observed() &&
                      *name != isolate->heap()->hidden_string();
   if (is_observed && lookup.IsProperty()) {
     if (lookup.IsDataProperty()) old_value =
         Object::GetProperty(object, name);
     old_attributes = lookup.GetAttributes();
   }
 
   // Check of IsReadOnly removed from here in clone.
   switch (lookup.type()) {
     case NORMAL:
@@ skipping 962 matching lines @@
 
   if (object->IsJSGlobalProxy()) {
     Handle<Object> proto(object->GetPrototype(), isolate);
     if (proto->IsNull()) return factory->false_value();
     ASSERT(proto->IsJSGlobalObject());
     return DeleteElement(Handle<JSObject>::cast(proto), index, mode);
   }
 
   Handle<Object> old_value;
   bool should_enqueue_change_record = false;
-  if (FLAG_harmony_observation && object->map()->is_observed()) {
+  if (object->map()->is_observed()) {
     should_enqueue_change_record = HasLocalElement(object, index);
     if (should_enqueue_change_record) {
       old_value = object->GetLocalElementAccessorPair(index) != NULL
           ? Handle<Object>::cast(factory->the_hole_value())
           : Object::GetElement(isolate, object, index);
     }
   }
 
   // Skip interceptor if forcing deletion.
   Handle<Object> result;
@@ skipping 50 matching lines @@
       Handle<Object> args[2] = { name, object };
       Handle<Object> error = isolate->factory()->NewTypeError(
           "strict_delete_property", HandleVector(args, ARRAY_SIZE(args)));
       isolate->Throw(*error);
       return Handle<Object>();
     }
     return isolate->factory()->false_value();
   }
 
   Handle<Object> old_value = isolate->factory()->the_hole_value();
-  bool is_observed = FLAG_harmony_observation &&
-                     object->map()->is_observed() &&
+  bool is_observed = object->map()->is_observed() &&
                      *name != isolate->heap()->hidden_string();
   if (is_observed && lookup.IsDataProperty()) {
     old_value = Object::GetProperty(object, name);
   }
   Handle<Object> result;
 
   // Check for interceptor.
   if (lookup.IsInterceptor()) {
     // Skip interceptor if forcing a deletion.
     if (mode == FORCE_DELETION) {
@@ skipping 215 matching lines @@
 
   // Do a map transition, other objects with this map may still
   // be extensible.
   // TODO(adamk): Extend the NormalizedMapCache to handle non-extensible maps.
   Handle<Map> new_map = Map::Copy(handle(object->map()));
 
   new_map->set_is_extensible(false);
   JSObject::MigrateToMap(object, new_map);
   ASSERT(!object->map()->is_extensible());
 
-  if (FLAG_harmony_observation && object->map()->is_observed()) {
+  if (object->map()->is_observed()) {
     EnqueueChangeRecord(object, "preventExtensions", Handle<Name>(),
                         isolate->factory()->the_hole_value());
   }
   return object;
 }
 
 
 template<typename Dictionary>
 static void FreezeDictionary(Dictionary* dictionary) {
   int capacity = dictionary->Capacity();
@@ skipping 837 matching lines @@
 
   // Try to flatten before operating on the string.
   if (name->IsString()) String::cast(*name)->TryFlatten();
 
   if (!JSObject::CanSetCallback(object, name)) return;
 
   uint32_t index = 0;
   bool is_element = name->AsArrayIndex(&index);
 
   Handle<Object> old_value = isolate->factory()->the_hole_value();
-  bool is_observed = FLAG_harmony_observation &&
-                     object->map()->is_observed() &&
+  bool is_observed = object->map()->is_observed() &&
                      *name != isolate->heap()->hidden_string();
   bool preexists = false;
   if (is_observed) {
     if (is_element) {
       preexists = HasLocalElement(object, index);
       if (preexists && object->GetLocalElementAccessorPair(index) == NULL) {
         old_value = Object::GetElement(isolate, object, index);
       }
     } else {
       LookupResult lookup(isolate);
@@ skipping 5040 matching lines @@
                   Handle<JSFunction>(isolate->observers_end_perform_splice()),
                   isolate->factory()->undefined_value(), ARRAY_SIZE(args), args,
                   &threw);
   ASSERT(!threw);
 }
 
 
 MaybeObject* JSArray::SetElementsLength(Object* len) {
   // We should never end in here with a pixel or external array.
   ASSERT(AllowsSetElementsLength());
-  if (!(FLAG_harmony_observation && map()->is_observed()))
+  if (!map()->is_observed())
     return GetElementsAccessor()->SetLength(this, len);
 
   Isolate* isolate = GetIsolate();
   HandleScope scope(isolate);
   Handle<JSArray> self(this);
   List<uint32_t> indices;
   List<Handle<Object> > old_values;
   Handle<Object> old_length_handle(self->length(), isolate);
   Handle<Object> new_length_handle(len, isolate);
   uint32_t old_length = 0;
@@ skipping 1108 matching lines @@
     return Handle<Object>();
   }
 
   // Normalize the elements to enable attributes on the property.
   if ((attributes & (DONT_DELETE | DONT_ENUM | READ_ONLY)) != 0) {
     Handle<SeededNumberDictionary> dictionary = NormalizeElements(object);
     // Make sure that we never go back to fast case.
     dictionary->set_requires_slow_elements();
   }
 
-  if (!(FLAG_harmony_observation && object->map()->is_observed())) {
+  if (!object->map()->is_observed()) {
     return object->HasIndexedInterceptor()
       ? SetElementWithInterceptor(object, index, value, attributes, strict_mode,
                                   check_prototype,
                                    set_mode)
       : SetElementWithoutInterceptor(object, index, value, attributes,
                                      strict_mode,
                                      check_prototype,
                                      set_mode);
   }
 
@@ skipping 581 matching lines @@
 
 bool JSObject::ShouldConvertToFastElements() {
   ASSERT(HasDictionaryElements() || HasDictionaryArgumentsElements());
   // If the elements are sparse, we should not go back to fast case.
   if (!HasDenseElements()) return false;
   // An object requiring access checks is never allowed to have fast
   // elements.  If it had fast elements we would skip security checks.
   if (IsAccessCheckNeeded()) return false;
   // Observed objects may not go to fast mode because they rely on map checks,
   // and for fast element accesses we sometimes check element kinds only.
-  if (FLAG_harmony_observation && map()->is_observed()) return false;
+  if (map()->is_observed()) return false;
 
   FixedArray* elements = FixedArray::cast(this->elements());
   SeededNumberDictionary* dictionary = NULL;
   if (elements->map() == GetHeap()->sloppy_arguments_elements_map()) {
     dictionary = SeededNumberDictionary::cast(elements->get(1));
   } else {
     dictionary = SeededNumberDictionary::cast(elements);
   }
   // If an element has been added at a very high index in the elements
   // dictionary, we cannot go back to fast case.
@@ skipping 3320 matching lines @@
 #define ERROR_MESSAGES_TEXTS(C, T) T,
   static const char* error_messages_[] = {
       ERROR_MESSAGES_LIST(ERROR_MESSAGES_TEXTS)
   };
 #undef ERROR_MESSAGES_TEXTS
   return error_messages_[reason];
 }
 
 
 } }  // namespace v8::internal