Append to descriptors over map.

src/factory.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 894 matching lines @@
   DescriptorArray::WhitenessWitness witness(*result);
 
   // Copy the descriptors from the array.
   if (0 < descriptor_count) {
     result->SetLastAdded(array->LastAdded());
     for (int i = 0; i < descriptor_count; i++) {
       result->CopyFrom(i, *array, i, witness);
     }
   }
 
+  map->set_instance_descriptors(*result);
+
   // Fill in new callback descriptors.  Process the callbacks from
   // back to front so that the last callback with a given name takes
   // precedence over previously added callbacks with that name.
   for (int i = nof_callbacks - 1; i >= 0; i--) {
     Handle<AccessorInfo> entry =
         Handle<AccessorInfo>(AccessorInfo::cast(callbacks.get(i)));
     // Ensure the key is a symbol before writing into the instance descriptor.
     Handle<String> key =
         SymbolFromString(Handle<String>(String::cast(entry->name())));
     // Check if a descriptor with this name already exists before writing.
     if (LinearSearch(*result, *key, result->NumberOfSetDescriptors()) ==
         DescriptorArray::kNotFound) {
       CallbacksDescriptor desc(*key, *entry, entry->property_attributes());
-      result->Append(&desc, witness);
+      map->AppendDescriptor(&desc, witness);
     }
   }
 
   int new_number_of_descriptors = result->NumberOfSetDescriptors();
-  // Don't replace the descriptor array if there were no new elements.
-  if (new_number_of_descriptors == descriptor_count) return;
+  // Reinstall the original descriptor array if no new elements were added.
+  if (new_number_of_descriptors == descriptor_count) {
+    map->set_instance_descriptors(*array);
+    return;
+  }
 
   // If duplicates were detected, allocate a result of the right size
   // and transfer the elements.
   if (new_number_of_descriptors < result->length()) {
     Handle<DescriptorArray> new_result =
         NewDescriptorArray(new_number_of_descriptors);
     for (int i = 0; i < new_number_of_descriptors; i++) {
       new_result->CopyFrom(i, *result, i, witness);
     }
     new_result->SetLastAdded(result->LastAdded());
-    result = new_result;
+    map->set_instance_descriptors(*new_result);
   }
-
-  map->set_instance_descriptors(*result);
 }
 
 
 Handle<JSObject> Factory::NewJSObject(Handle<JSFunction> constructor,
                                       PretenureFlag pretenure) {
   CALL_HEAP_FUNCTION(
       isolate(),
       isolate()->heap()->AllocateJSObject(*constructor, pretenure), JSObject);
 }
 
@@ skipping 499 matching lines @@
 
 
 Handle<Object> Factory::ToBoolean(bool value) {
   return Handle<Object>(value
                         ? isolate()->heap()->true_value()
                         : isolate()->heap()->false_value());
 }
 
 
 } }  // namespace v8::internal