Introduce StackArgumentsAccessor class for X64

src/x64/macro-assembler-x64.h

Index: src/x64/macro-assembler-x64.h
diff --git a/src/x64/macro-assembler-x64.h b/src/x64/macro-assembler-x64.h
index e611c8ae27999a9520d0aa07bfa050b51a0bb831..2eb12a5f9538ba5b3d138cb589c5093bb875d933 100644
--- a/src/x64/macro-assembler-x64.h
+++ b/src/x64/macro-assembler-x64.h
@@ -1523,6 +1523,31 @@ inline Operand StackOperandForReturnAddress(int32_t disp) {
 }
 
 
+// Computes the argument address in reverse order, i.e., from the last argument
+// at rsp + kPCOnStackSize.
+inline Operand StackOperandForReversedArgument(int index) {
+  return Operand(rsp, kPCOnStackSize + index * kPointerSize);
+}
+
+
+// Computes the argument address in reverse order, i.e., from the last argument
+// at rsp + kPCOnStackSize.
+inline Operand StackOperandForReversedArgument(Register index, int offset) {
+  return Operand(rsp, index, times_pointer_size,
+                 kPCOnStackSize + offset * kPointerSize);
+}
+
+
+inline Operand StackOperandForReceiver(int index) {
+  return StackOperandForReversedArgument(index);
+}
+
+
+inline Operand StackOperandForReceiver(Register index) {
+  return StackOperandForReversedArgument(index, 0);
+}
+
+
 #ifdef GENERATED_CODE_COVERAGE
 extern void LogGeneratedCodeCoverage(const char* file_line);
 #define CODE_COVERAGE_STRINGIFY(x) #x