Append to descriptors over map.

src/objects-inl.h

 // 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 2092 matching lines @@
                                desc->GetKey());
   NoIncrementalWriteBarrierSet(this,
                                ToValueIndex(descriptor_number),
                                desc->GetValue());
   NoIncrementalWriteBarrierSet(this,
                                ToDetailsIndex(descriptor_number),
                                desc->GetDetails().AsSmi());
 }
 
 
-void DescriptorArray::Append(Descriptor* desc,
-                             const WhitenessWitness& witness) {
-  int descriptor_number = NumberOfSetDescriptors();
+int DescriptorArray::Append(Descriptor* desc,
+                            const WhitenessWitness& witness,
+                            int number_of_set_descriptors) {
+  int descriptor_number = number_of_set_descriptors;
   int enumeration_index = descriptor_number + 1;
   desc->SetEnumerationIndex(enumeration_index);
 
   uint32_t hash = desc->GetKey()->Hash();
 
   for (; descriptor_number > 0; --descriptor_number) {
     String* key = GetKey(descriptor_number - 1);
     if (key->Hash() <= hash) break;
     Object* value = GetValue(descriptor_number - 1);
     PropertyDetails details = GetDetails(descriptor_number - 1);
     Descriptor moved_descriptor(key, value, details);
     Set(descriptor_number, &moved_descriptor, witness);
   }
 
   Set(descriptor_number, desc, witness);
-  SetLastAdded(descriptor_number);
+  return descriptor_number;
 }
 
 
 void DescriptorArray::NoIncrementalWriteBarrierSwapDescriptors(
     int first, int second) {
   NoIncrementalWriteBarrierSwap(this, ToKeyIndex(first), ToKeyIndex(second));
   NoIncrementalWriteBarrierSwap(this,
                                 ToValueIndex(first),
                                 ToValueIndex(second));
   NoIncrementalWriteBarrierSwap(this,
@@ skipping 1405 matching lines @@
   } else {
     ASSERT(object->IsMap() || object->IsUndefined());
   }
 #endif
   WRITE_FIELD(this, kInstanceDescriptorsOrBackPointerOffset, back_pointer);
   CONDITIONAL_WRITE_BARRIER(
       heap, this, kInstanceDescriptorsOrBackPointerOffset, back_pointer, mode);
 }
 
 
+void Map::AppendDescriptor(Descriptor* desc,
+                           const DescriptorArray::WhitenessWitness& witness) {
+  DescriptorArray* descriptors = instance_descriptors();
+  int set_descriptors = descriptors->NumberOfSetDescriptors();
+  int new_last_added = descriptors->Append(desc, witness, set_descriptors);
+  descriptors->SetLastAdded(new_last_added);
+}
+
 
 Object* Map::GetBackPointer() {
   Object* object = READ_FIELD(this, kInstanceDescriptorsOrBackPointerOffset);
   if (object->IsDescriptorArray()) {
     return DescriptorArray::cast(object)->back_pointer_storage();
   } else {
     ASSERT(object->IsMap() || object->IsUndefined());
     return object;
   }
 }
@@ skipping 1802 matching lines @@
 #undef WRITE_UINT32_FIELD
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_