api accessor store ics should return passed value

src/x64/code-stubs-x64.cc

 // Copyright 2013 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 5159 matching lines @@
   // -----------------------------------
 
   Register callee = rax;
   Register call_data = rbx;
   Register holder = rcx;
   Register api_function_address = rdx;
   Register return_address = rdi;
   Register context = rsi;
 
   int argc = ArgumentBits::decode(bit_field_);
-  bool restore_context = RestoreContextBits::decode(bit_field_);
+  bool is_store = IsStoreBits::decode(bit_field_);
   bool call_data_undefined = CallDataUndefinedBits::decode(bit_field_);
 
   typedef FunctionCallbackArguments FCA;
 
   STATIC_ASSERT(FCA::kContextSaveIndex == 6);
   STATIC_ASSERT(FCA::kCalleeIndex == 5);
   STATIC_ASSERT(FCA::kDataIndex == 4);
   STATIC_ASSERT(FCA::kReturnValueOffset == 3);
   STATIC_ASSERT(FCA::kReturnValueDefaultValueIndex == 2);
   STATIC_ASSERT(FCA::kIsolateIndex == 1);
@@ skipping 55 matching lines @@
 
   // It's okay if api_function_address == callback_arg
   // but not arguments_arg
   ASSERT(!api_function_address.is(arguments_arg));
 
   // v8::InvocationCallback's argument.
   __ lea(arguments_arg, StackSpaceOperand(0));
 
   Address thunk_address = FUNCTION_ADDR(&InvokeFunctionCallback);
 
-  StackArgumentsAccessor args_from_rbp(rbp, FCA::kArgsLength,
+  // Accessor for FunctionCallbackInfo and first js arg.
+  StackArgumentsAccessor args_from_rbp(rbp, FCA::kArgsLength + 1,
                                        ARGUMENTS_DONT_CONTAIN_RECEIVER);
   Operand context_restore_operand = args_from_rbp.GetArgumentOperand(
-      FCA::kArgsLength - 1 - FCA::kContextSaveIndex);
+      FCA::kArgsLength - FCA::kContextSaveIndex);
+  // Stores return the first js argument
   Operand return_value_operand = args_from_rbp.GetArgumentOperand(
-      FCA::kArgsLength - 1 - FCA::kReturnValueOffset);
+      is_store ? 0 : FCA::kArgsLength - FCA::kReturnValueOffset);
   __ CallApiFunctionAndReturn(
       api_function_address,
       thunk_address,
       callback_arg,
       argc + FCA::kArgsLength + 1,
       return_value_operand,
-      restore_context ? &context_restore_operand : NULL);
+      &context_restore_operand);
 }
 
 
 void CallApiGetterStub::Generate(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- rsp[0]                  : return address
   //  -- rsp[8]                  : name
   //  -- rsp[16 - kArgsLength*8] : PropertyCallbackArguments object
   //  -- ...
   //  -- r8                    : api_function_address
@@ skipping 48 matching lines @@
                               return_value_operand,
                               NULL);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64