Simplify GetEnumPropertyKeys and avoid trimming fixed arrays in large object space.

src/handles.cc

 // 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 694 matching lines @@
                        *storage,
                        indices.is_null() ? Object::cast(Smi::FromInt(0))
                                          : Object::cast(*indices));
     if (cache_result) {
       object->map()->SetEnumLength(enum_size);
     }
 
     return ReduceFixedArrayTo(storage, enum_size);
   } else {
     Handle<NameDictionary> dictionary(object->property_dictionary());
-
-    int length = dictionary->NumberOfElements();
+    int length = dictionary->NumberOfEnumElements();
     if (length == 0) {
       return Handle<FixedArray>(isolate->heap()->empty_fixed_array());
     }
-
-    // The enumeration array is generated by allocating an array big enough to
-    // hold all properties that have been seen, whether they are are deleted or
-    // not. Subsequently all visible properties are added to the array. If some
-    // properties were not visible, the array is trimmed so it only contains
-    // visible properties. This improves over adding elements and sorting by
-    // index by having linear complexity rather than n*log(n).
-
-    // By comparing the monotonous NextEnumerationIndex to the NumberOfElements,
-    // we can predict the number of holes in the final array. If there will be
-    // more than 50% holes, regenerate the enumeration indices to reduce the
-    // number of holes to a minimum. This avoids allocating a large array if
-    // many properties were added but subsequently deleted.
-    int next_enumeration = dictionary->NextEnumerationIndex();
-    if (!object->IsGlobalObject() && next_enumeration > (length * 3) / 2) {
-      NameDictionary::DoGenerateNewEnumerationIndices(dictionary);
-      next_enumeration = dictionary->NextEnumerationIndex();
-    }
-
-    Handle<FixedArray> storage =
-        isolate->factory()->NewFixedArray(next_enumeration);
-
-    storage = Handle<FixedArray>(dictionary->CopyEnumKeysTo(*storage));
-    ASSERT(storage->length() == object->NumberOfLocalProperties(DONT_SHOW));
+    Handle<FixedArray> storage = isolate->factory()->NewFixedArray(length);
+    dictionary->CopyEnumKeysTo(*storage);
     return storage;
   }
 }
 
 
 DeferredHandleScope::DeferredHandleScope(Isolate* isolate)
     : impl_(isolate->handle_scope_implementer()) {
   impl_->BeginDeferredScope();
   HandleScopeData* data = impl_->isolate()->handle_scope_data();
   Object** new_next = impl_->GetSpareOrNewBlock();
@@ skipping 36 matching lines @@
                                    Handle<Code> code) {
   heap->EnsureWeakObjectToCodeTable();
   Handle<DependentCode> dep(heap->LookupWeakObjectToCodeDependency(*object));
   dep = DependentCode::Insert(dep, DependentCode::kWeaklyEmbeddedGroup, code);
   CALL_HEAP_FUNCTION_VOID(heap->isolate(),
                           heap->AddWeakObjectToCodeDependency(*object, *dep));
 }
 
 
 } }  // namespace v8::internal