Optimize prototype chain when creating initial maps for functions used as constructors

src/objects.cc

 // Copyright 2013 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.
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/allocation-site-scopes.h"
 #include "src/api.h"
 #include "src/arguments.h"
@@ skipping 10171 matching lines @@
     instance_type = JS_OBJECT_TYPE;
     instance_size = function->shared()->CalculateInstanceSize();
     in_object_properties = function->shared()->CalculateInObjectProperties();
   }
   Handle<Map> map = isolate->factory()->NewMap(instance_type, instance_size);
 
   // Fetch or allocate prototype.
   Handle<Object> prototype;
   if (function->has_instance_prototype()) {
     prototype = handle(function->instance_prototype(), isolate);
+    for (Handle<Object> p = prototype; !p->IsNull() && !p->IsJSProxy();
+         p = Object::GetPrototype(isolate, p)) {
+      JSObject::OptimizeAsPrototype(Handle<JSObject>::cast(p));
+    }
   } else {
     prototype = isolate->factory()->NewFunctionPrototype(function);
   }
   map->set_inobject_properties(in_object_properties);
   map->set_unused_property_fields(in_object_properties);
   map->set_prototype(*prototype);
   ASSERT(map->has_fast_object_elements());
 
   // Finally link initial map and constructor function.
   function->set_initial_map(*map);
@@ skipping 6892 matching lines @@
 #define ERROR_MESSAGES_TEXTS(C, T) T,
   static const char* error_messages_[] = {
       ERROR_MESSAGES_LIST(ERROR_MESSAGES_TEXTS)
   };
 #undef ERROR_MESSAGES_TEXTS
   return error_messages_[reason];
 }
 
 
 } }  // namespace v8::internal