[Isolates] Avoid dereferencing Isolate::Current() to check oddball identities...

src/handles.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 624 matching lines @@
                                           KeyCollectionType type) {
   Handle<FixedArray> content = Factory::empty_fixed_array();
   Handle<JSObject> arguments_boilerplate =
       Handle<JSObject>(
           Isolate::Current()->context()->global_context()->
               arguments_boilerplate());
   Handle<JSFunction> arguments_function =
       Handle<JSFunction>(
           JSFunction::cast(arguments_boilerplate->map()->constructor()));
 
+  Heap* heap = HEAP;
   // Only collect keys if access is permitted.
   for (Handle<Object> p = object;
-       *p != HEAP->null_value();
+       *p != heap->null_value();
        p = Handle<Object>(p->GetPrototype())) {
     Handle<JSObject> current(JSObject::cast(*p));
 
     // Check access rights if required.
     if (current->IsAccessCheckNeeded() &&
         !Isolate::Current()->MayNamedAccess(*current, HEAP->undefined_value(),
                                             v8::ACCESS_KEYS)) {
       Isolate::Current()->ReportFailedAccessCheck(*current, v8::ACCESS_KEYS);
       break;
     }
@@ skipping 170 matching lines @@
 
 OptimizedObjectForAddingMultipleProperties::
 ~OptimizedObjectForAddingMultipleProperties() {
   // Reoptimize the object to allow fast property access.
   if (has_been_transformed_) {
     TransformToFastProperties(object_, unused_property_fields_);
   }
 }
 
 } }  // namespace v8::internal