Allocate global object as a normalized object

src/heap.cc

 // Copyright 2009 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 2085 matching lines @@
   // for example, JSArray::JSArrayVerify).
   obj->InitializeBody(map->instance_size());
 }
 
 
 Object* Heap::AllocateJSObjectFromMap(Map* map, PretenureFlag pretenure) {
   // JSFunctions should be allocated using AllocateFunction to be
   // properly initialized.
   ASSERT(map->instance_type() != JS_FUNCTION_TYPE);
 
+  // Both types of globla objects should be allocated using
+  // AllocateGloblaObject to be properly initialized.
+  ASSERT(map->instance_type() != JS_GLOBAL_OBJECT_TYPE);
+  ASSERT(map->instance_type() != JS_BUILTINS_OBJECT_TYPE);
+
   // Allocate the backing storage for the properties.
   int prop_size = map->unused_property_fields() - map->inobject_properties();
   Object* properties = AllocateFixedArray(prop_size, pretenure);
   if (properties->IsFailure()) return properties;
 
   // Allocate the JSObject.
   AllocationSpace space =
       (pretenure == TENURED) ? OLD_POINTER_SPACE : NEW_SPACE;
   if (map->instance_size() > MaxObjectSizeInPagedSpace()) space = LO_SPACE;
   Object* obj = Allocate(map, space);
@@ skipping 20 matching lines @@
   Object* result =
       AllocateJSObjectFromMap(constructor->initial_map(), pretenure);
   // Make sure result is NOT a global object if valid.
   ASSERT(result->IsFailure() || !result->IsGlobalObject());
   return result;
 }
 
 
 Object* Heap::AllocateGlobalObject(JSFunction* constructor) {
   ASSERT(constructor->has_initial_map());
+  Map* map = constructor->initial_map();
+
   // Make sure no field properties are described in the initial map.
   // This guarantees us that normalizing the properties does not
   // require us to change property values to JSGlobalPropertyCells.
-  ASSERT(constructor->initial_map()->NextFreePropertyIndex() == 0);
+  ASSERT(map->NextFreePropertyIndex() == 0);
 
   // Make sure we don't have a ton of pre-allocated slots in the
   // global objects. They will be unused once we normalize the object.
-  ASSERT(constructor->initial_map()->unused_property_fields() == 0);
-  ASSERT(constructor->initial_map()->inobject_properties() == 0);
+  ASSERT(map->unused_property_fields() == 0);
+  ASSERT(map->inobject_properties() == 0);
 
-  // Allocate the object based on the constructors initial map.
-  Object* result = AllocateJSObjectFromMap(constructor->initial_map(), TENURED);
-  if (result->IsFailure()) return result;
+  // Initial size of the backing store to avoid resize of the storage during
+  // bootstrapping. The size differs between the JS global object ad the
+  // builtins object.
+  int initial_size = map->instance_type() == JS_GLOBAL_OBJECT_TYPE ? 64 : 512;
 
-  // Normalize the result.
-  JSObject* global = JSObject::cast(result);
-  result = global->NormalizeProperties(CLEAR_INOBJECT_PROPERTIES);
-  if (result->IsFailure()) return result;
+  // Allocate a dictionary object for backing storage.
+  Object* obj =
+      StringDictionary::Allocate(
+          map->NumberOfDescribedProperties() * 2 + initial_size);
+  if (obj->IsFailure()) return obj;
+  StringDictionary* dictionary = StringDictionary::cast(obj);
+
+  // The global object might be created from an object template with accessors.
+  // Fill these accessors into the dictionary.
+  DescriptorArray* descs = map->instance_descriptors();
+  for (int i = 0; i < descs->number_of_descriptors(); i++) {
+    PropertyDetails details = descs->GetDetails(i);
+    ASSERT(details.type() == CALLBACKS);  // Only accessors are expected.
+    PropertyDetails d =
+        PropertyDetails(details.attributes(), CALLBACKS, details.index());
+    Object* value = descs->GetCallbacksObject(i);
+    value = Heap::AllocateJSGlobalPropertyCell(value);
+    if (value->IsFailure()) return value;
+
+    Object* result = dictionary->Add(descs->GetKey(i), value, d);
+    if (result->IsFailure()) return result;
+    dictionary = StringDictionary::cast(result);
+  }
+
+  // Allocate the global object and initialize it with the backing store.
+  obj = Allocate(map, OLD_POINTER_SPACE);
+  if (obj->IsFailure()) return obj;
+  JSObject* global = JSObject::cast(obj);
+  InitializeJSObjectFromMap(global, dictionary, map);
+
+  // Create a new map for the global object.
+  obj = map->CopyDropDescriptors();
+  if (obj->IsFailure()) return obj;
+  Map* new_map = Map::cast(obj);
+
+  // Setup the global object as a normalized object.
+  global->set_map(new_map);
+  global->map()->set_instance_descriptors(Heap::empty_descriptor_array());
+  global->set_properties(dictionary);
 
   // Make sure result is a global object with properties in dictionary.
   ASSERT(global->IsGlobalObject());
   ASSERT(!global->HasFastProperties());
   return global;
 }
 
 
 Object* Heap::CopyJSObject(JSObject* source) {
   // Never used to copy functions.  If functions need to be copied we
@@ skipping 1671 matching lines @@
 #ifdef DEBUG
 bool Heap::GarbageCollectionGreedyCheck() {
   ASSERT(FLAG_gc_greedy);
   if (Bootstrapper::IsActive()) return true;
   if (disallow_allocation_failure()) return true;
   return CollectGarbage(0, NEW_SPACE);
 }
 #endif
 
 } }  // namespace v8::internal