Fix issue 582: preserve construct stub on first allocation in case we can't optimize it.

src/runtime.cc

 // Copyright 2006-2009 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 4764 matching lines @@
   if (FLAG_inline_new
       && shared->has_only_simple_this_property_assignments()) {
     ConstructStubCompiler compiler;
     Object* code = compiler.CompileConstructStub(*shared);
     if (code->IsFailure()) {
       return Builtins::builtin(Builtins::JSConstructStubGeneric);
     }
     return Code::cast(code);
   }
 
-  return Builtins::builtin(Builtins::JSConstructStubGeneric);
+  return shared->construct_stub();
 }
 
 
 static Object* Runtime_NewObject(Arguments args) {
   HandleScope scope;
   ASSERT(args.length() == 1);
 
   Handle<Object> constructor = args.at<Object>(0);
 
   // If the constructor isn't a proper function we throw a type error.
@@ skipping 3367 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     Counters::gc_last_resort_from_js.Increment();
     Heap::CollectAllGarbage(false);
   }
 }
 
 
 } }  // namespace v8::internal