Use kRegisterSize when calling C++ runtime

src/x64/macro-assembler-x64.cc

Index: src/x64/macro-assembler-x64.cc
===================================================================
--- src/x64/macro-assembler-x64.cc	(revision 15891)
+++ src/x64/macro-assembler-x64.cc	(working copy)
@@ -3507,7 +3507,7 @@
   // Optionally save all XMM registers.
   if (save_doubles) {
     int space = XMMRegister::kMaxNumRegisters * kDoubleSize +
-        arg_stack_space * kPointerSize;
+        arg_stack_space * kRegisterSize;
     subq(rsp, Immediate(space));
     int offset = -2 * kPointerSize;
     for (int i = 0; i < XMMRegister::NumAllocatableRegisters(); i++) {
@@ -3515,7 +3515,7 @@
       movsd(Operand(rbp, offset - ((i + 1) * kDoubleSize)), reg);
     }
   } else if (arg_stack_space > 0) {
-    subq(rsp, Immediate(arg_stack_space * kPointerSize));
+    subq(rsp, Immediate(arg_stack_space * kRegisterSize));
   }
 
   // Get the required frame alignment for the OS.
@@ -4375,7 +4375,7 @@
   ASSERT(IsPowerOf2(frame_alignment));
   int argument_slots_on_stack =
       ArgumentStackSlotsForCFunctionCall(num_arguments);
-  subq(rsp, Immediate((argument_slots_on_stack + 1) * kPointerSize));
+  subq(rsp, Immediate((argument_slots_on_stack + 1) * kRegisterSize));
   and_(rsp, Immediate(-frame_alignment));
   movq(Operand(rsp, argument_slots_on_stack * kPointerSize), kScratchRegister);
 }
@@ -4400,7 +4400,7 @@
   ASSERT(num_arguments >= 0);
   int argument_slots_on_stack =
       ArgumentStackSlotsForCFunctionCall(num_arguments);
-  movq(rsp, Operand(rsp, argument_slots_on_stack * kPointerSize));
+  movq(rsp, Operand(rsp, argument_slots_on_stack * kRegisterSize));
 }