Fix some usage of "this" in builtins

src/x64/codegen-x64.cc

 // Copyright 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 3604 matching lines @@
   Result obj = frame_->Pop();
   obj.ToRegister();
   Condition is_smi = masm_->CheckSmi(obj.reg());
   destination()->false_target()->Branch(is_smi);
   __ CmpObjectType(obj.reg(), JS_FUNCTION_TYPE, kScratchRegister);
   obj.Unuse();
   destination()->Split(equal);
 }
 
 
+void CodeGenerator::GenerateIsUndetectableObject(ZoneList<Expression*>* args) {
+  ASSERT(args->length() == 1);
+  Load(args->at(0));
+  Result obj = frame_->Pop();
+  obj.ToRegister();
+  Condition is_smi = masm_->CheckSmi(obj.reg());
+  destination()->false_target()->Branch(is_smi);
+  __ movq(kScratchRegister, FieldOperand(obj.reg(), HeapObject::kMapOffset));
+  __ movzxbl(kScratchRegister,
+             FieldOperand(kScratchRegister, Map::kBitFieldOffset));
+  __ testl(kScratchRegister, Immediate(1 << Map::kIsUndetectable));
+  obj.Unuse();
+  destination()->Split(not_zero);
+}
+
+
 void CodeGenerator::GenerateIsConstructCall(ZoneList<Expression*>* args) {
   ASSERT(args->length() == 0);
 
   // Get the frame pointer for the calling frame.
   Result fp = allocator()->Allocate();
   __ movq(fp.reg(), Operand(rbp, StandardFrameConstants::kCallerFPOffset));
 
   // Skip the arguments adaptor frame if it exists.
   Label check_frame_marker;
   __ SmiCompare(Operand(fp.reg(), StandardFrameConstants::kContextOffset),
@@ skipping 4750 matching lines @@
   // Call the function from C++.
   return FUNCTION_CAST<ModuloFunction>(buffer);
 }
 
 #endif
 
 
 #undef __
 
 } }  // namespace v8::internal