Simplify the way constructors are called and avoid pushing...

src/x64/codegen-x64.cc

 // Copyright 2010 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 5638 matching lines @@
 
 void CodeGenerator::VisitCallNew(CallNew* node) {
   Comment cmnt(masm_, "[ CallNew");
 
   // According to ECMA-262, section 11.2.2, page 44, the function
   // expression in new calls must be evaluated before the
   // arguments. This is different from ordinary calls, where the
   // actual function to call is resolved after the arguments have been
   // evaluated.
 
-  // Compute function to call and use the global object as the
-  // receiver. There is no need to use the global proxy here because
-  // it will always be replaced with a newly allocated object.
+  // Push constructor on the stack.  If it's not a function it's used as
+  // receiver for CALL_NON_FUNCTION, otherwise the value on the stack is
+  // ignored.
   Load(node->expression());
-  LoadGlobal();
 
   // Push the arguments ("left-to-right") on the stack.
   ZoneList<Expression*>* args = node->arguments();
   int arg_count = args->length();
   for (int i = 0; i < arg_count; i++) {
     Load(args->at(i));
   }
 
   // Call the construct call builtin that handles allocation and
   // constructor invocation.
   CodeForSourcePosition(node->position());
   Result result = frame_->CallConstructor(arg_count);
-  // Replace the function on the stack with the result.
-  frame_->SetElementAt(0, &result);
+  frame_->Push(&result);
 }
 
 
 void CodeGenerator::GenerateIsSmi(ZoneList<Expression*>* args) {
   ASSERT(args->length() == 1);
   Load(args->at(0));
   Result value = frame_->Pop();
   value.ToRegister();
   ASSERT(value.is_valid());
   Condition is_smi = masm_->CheckSmi(value.reg());
@@ skipping 7167 matching lines @@
 #undef __
 
 void RecordWriteStub::Generate(MacroAssembler* masm) {
   masm->RecordWriteHelper(object_, addr_, scratch_);
   masm->ret(0);
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64