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

src/x64/builtins-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 879 matching lines @@
 
   // Jump to the function-specific construct stub.
   __ movq(rbx, FieldOperand(rdi, JSFunction::kSharedFunctionInfoOffset));
   __ movq(rbx, FieldOperand(rbx, SharedFunctionInfo::kConstructStubOffset));
   __ lea(rbx, FieldOperand(rbx, Code::kHeaderSize));
   __ jmp(rbx);
 
   // rdi: called object
   // rax: number of arguments
   __ bind(&non_function_call);
-  // CALL_NON_FUNCTION expects the non-function constructor as receiver
-  // (instead of the original receiver from the call site).  The receiver is
-  // stack element argc+1.
-  __ movq(Operand(rsp, rax, times_pointer_size, kPointerSize), rdi);
   // Set expected number of arguments to zero (not changing rax).
   __ movq(rbx, Immediate(0));
   __ GetBuiltinEntry(rdx, Builtins::CALL_NON_FUNCTION_AS_CONSTRUCTOR);
   __ Jump(Handle<Code>(builtin(ArgumentsAdaptorTrampoline)),
           RelocInfo::CODE_TARGET);
 }
 
 
 static void Generate_JSConstructStubHelper(MacroAssembler* masm,
                                            bool is_api_function) {
@@ skipping 392 matching lines @@
   __ LeaveInternalFrame();
 
   // Do a tail-call of the compiled function.
   __ lea(rcx, FieldOperand(rax, Code::kHeaderSize));
   __ jmp(rcx);
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64