Partial recover from performance degradation after handlification of ElementsAccessor::CopyElements…

src/factory.h

 // Copyright 2014 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.
 
 #ifndef V8_FACTORY_H_
 #define V8_FACTORY_H_
 
 #include "isolate.h"
 
 namespace v8 {
@@ skipping 318 matching lines @@
       ElementsKind elements_kind,
       int length,
       int capacity,
       ArrayStorageAllocationMode mode = INITIALIZE_ARRAY_ELEMENTS_WITH_HOLE,
       PretenureFlag pretenure = NOT_TENURED);
 
   Handle<JSArray> NewJSArray(
       int capacity,
       ElementsKind elements_kind = TERMINAL_FAST_ELEMENTS_KIND,
       PretenureFlag pretenure = NOT_TENURED) {
+    if (capacity != 0) {
+      elements_kind = GetHoleyElementsKind(elements_kind);
+    }
     return NewJSArray(elements_kind, 0, capacity,
                       INITIALIZE_ARRAY_ELEMENTS_WITH_HOLE, pretenure);
   }
 
   Handle<JSArray> NewJSArrayWithElements(
       Handle<FixedArrayBase> elements,
       ElementsKind elements_kind,
       int length,
       PretenureFlag pretenure = NOT_TENURED);
 
@@ skipping 240 matching lines @@
 
   // Update the map cache in the native context with (keys, map)
   Handle<MapCache> AddToMapCache(Handle<Context> context,
                                  Handle<FixedArray> keys,
                                  Handle<Map> map);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_FACTORY_H_