Let DescriptorArray::Append insert at proper position, avoiding need for resorting.

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 874 matching lines @@
                      Code);
 }
 
 
 Handle<String> Factory::SymbolFromString(Handle<String> value) {
   CALL_HEAP_FUNCTION(isolate(),
                      isolate()->heap()->LookupSymbol(*value), String);
 }
 
 
-Handle<DescriptorArray> Factory::CopyAppendCallbackDescriptors(
-    Handle<DescriptorArray> array,
-    Handle<Object> descriptors) {
+void Factory::CopyAppendCallbackDescriptors(Handle<Map> map,
+                                            Handle<Object> descriptors) {
+  Handle<DescriptorArray> array(map->instance_descriptors());
   v8::NeanderArray callbacks(descriptors);
   int nof_callbacks = callbacks.length();
   int descriptor_count = array->number_of_descriptors();
   Handle<DescriptorArray> result =
       NewDescriptorArray(descriptor_count + nof_callbacks);
 
   // Ensure that marking will not progress and change color of objects.
   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);
     }
   }
 
   // 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,
-                     EXPECT_UNSORTED,
-                     *key,
-                     result->NumberOfSetDescriptors()) ==
+    if (LinearSearch(*result, *key, result->NumberOfSetDescriptors()) ==
         DescriptorArray::kNotFound) {
       CallbacksDescriptor desc(*key, *entry, entry->property_attributes());
       result->Append(&desc, witness);
     }
   }
 
   int new_number_of_descriptors = result->NumberOfSetDescriptors();
-  // Return the old descriptor array if there were no new elements.
-  if (new_number_of_descriptors == descriptor_count) return array;
+  // Don't replace the descriptor array if there were no new elements.
+  if (new_number_of_descriptors == descriptor_count) 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;
   }
 
-  // Sort the result before returning.
-  result->Sort(witness);
-  return 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 367 matching lines @@
   // Set instance call-as-function information in the map.
   if (!obj->instance_call_handler()->IsUndefined()) {
     map->set_has_instance_call_handler();
   }
 
   result->shared()->set_function_data(*obj);
   result->shared()->set_construct_stub(*construct_stub);
   result->shared()->DontAdaptArguments();
 
   // Recursively copy parent templates' accessors, 'data' may be modified.
-  Handle<DescriptorArray> array =
-      Handle<DescriptorArray>(map->instance_descriptors());
   while (true) {
     Handle<Object> props = Handle<Object>(obj->property_accessors());
     if (!props->IsUndefined()) {
-      array = CopyAppendCallbackDescriptors(array, props);
+      CopyAppendCallbackDescriptors(map, props);
     }
     Handle<Object> parent = Handle<Object>(obj->parent_template());
     if (parent->IsUndefined()) break;
     obj = Handle<FunctionTemplateInfo>::cast(parent);
   }
-  if (!array->IsEmpty()) {
-    map->set_instance_descriptors(*array);
-  }
 
   ASSERT(result->shared()->IsApiFunction());
   return result;
 }
 
 
 Handle<MapCache> Factory::NewMapCache(int at_least_space_for) {
   CALL_HEAP_FUNCTION(isolate(),
                      MapCache::Allocate(at_least_space_for), MapCache);
 }
@@ skipping 103 matching lines @@
 
 
 Handle<Object> Factory::ToBoolean(bool value) {
   return Handle<Object>(value
                         ? isolate()->heap()->true_value()
                         : isolate()->heap()->false_value());
 }
 
 
 } }  // namespace v8::internal