Port faster callbacks invocation to x64.

src/ia32/codegen-ia32.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 12257 matching lines @@
 // using the location_ field directly.  If false, it is passed and
 // returned as a pointer to a handle.
 #ifdef USING_BSD_ABI
 static const bool kPassHandlesDirectly = true;
 #else
 static const bool kPassHandlesDirectly = false;
 #endif
 
 
 void ApiGetterEntryStub::Generate(MacroAssembler* masm) {
-  Label get_result;
+  Label empty_handle;
   Label prologue;
   Label promote_scheduled_exception;
   __ EnterApiExitFrame(ExitFrame::MODE_NORMAL, kStackSpace, kArgc);
   STATIC_ASSERT(kArgc == 4);
   if (kPassHandlesDirectly) {
     // When handles as passed directly we don't have to allocate extra
     // space for and pass an out parameter.
     __ mov(Operand(esp, 0 * kPointerSize), ebx);  // name.
     __ mov(Operand(esp, 1 * kPointerSize), eax);  // arguments pointer.
   } else {
@@ skipping 22 matching lines @@
   ExternalReference scheduled_exception_address =
       ExternalReference::scheduled_exception_address();
   __ cmp(Operand::StaticVariable(scheduled_exception_address),
          Immediate(Factory::the_hole_value()));
   __ j(not_equal, &promote_scheduled_exception, not_taken);
   if (!kPassHandlesDirectly) {
     // The returned value is a pointer to the handle holding the result.
     // Dereference this to get to the location.
     __ mov(eax, Operand(eax, 0));
   }
-  // Check if the result handle holds 0
+  // Check if the result handle holds 0.
   __ test(eax, Operand(eax));
-  __ j(not_zero, &get_result, taken);
-  // It was zero; the result is undefined.
-  __ mov(eax, Factory::undefined_value());
-  __ jmp(&prologue);
+  __ j(zero, &empty_handle, not_taken);
   // It was non-zero.  Dereference to get the result value.
-  __ bind(&get_result);
   __ mov(eax, Operand(eax, 0));
   __ bind(&prologue);
   __ LeaveExitFrame(ExitFrame::MODE_NORMAL);
   __ ret(0);
   __ bind(&promote_scheduled_exception);
   __ TailCallRuntime(Runtime::kPromoteScheduledException, 0, 1);
+  __ bind(&empty_handle);
+  // It was zero; the result is undefined.
+  __ mov(eax, Factory::undefined_value());
+  __ jmp(&prologue);
 }
 
 
 void CEntryStub::GenerateCore(MacroAssembler* masm,
                               Label* throw_normal_exception,
                               Label* throw_termination_exception,
                               Label* throw_out_of_memory_exception,
                               bool do_gc,
                               bool always_allocate_scope,
                               int /* alignment_skew */) {
@@ skipping 1614 matching lines @@
   masm.GetCode(&desc);
   // Call the function from C++.
   return FUNCTION_CAST<MemCopyFunction>(buffer);
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32