Introduce StackArgumentsAccessor class for X64

src/x64/codegen-x64.h

Index: src/x64/codegen-x64.h
diff --git a/src/x64/codegen-x64.h b/src/x64/codegen-x64.h
index 5747e0bc6f0d19c3bbec0f654a4e2fb2ab052a93..9b8454a3535ac77a681439e8c2a8b986cb61d8d2 100644
--- a/src/x64/codegen-x64.h
+++ b/src/x64/codegen-x64.h
@@ -103,6 +103,73 @@ class MathExpGenerator : public AllStatic {
   DISALLOW_COPY_AND_ASSIGN(MathExpGenerator);
 };
 
+
+enum StackArgumentsAccessorReceiverMode {
+  ARGUMENTS_CONTAIN_RECEIVER,
+  ARGUMENTS_DONT_CONTAIN_RECEIVER
+};
+
+
+class StackArgumentsAccessor BASE_EMBEDDED {
+ public:
+  StackArgumentsAccessor(
+      Register base_reg,
+      int argument_count_immediate,
+      StackArgumentsAccessorReceiverMode receiver_mode =
+          ARGUMENTS_CONTAIN_RECEIVER,
+      int extra_displacement_to_last_argument = 0)
+      : base_reg_(base_reg),
+        argument_count_reg_(no_reg),
+        argument_count_immediate_(argument_count_immediate),
+        receiver_mode_(receiver_mode),
+        extra_displacement_to_last_argument_(
+            extra_displacement_to_last_argument) { }
+
+  StackArgumentsAccessor(
+      Register base_reg,
+      Register argument_count_reg,
+      StackArgumentsAccessorReceiverMode receiver_mode =
+          ARGUMENTS_CONTAIN_RECEIVER,
+      int extra_displacement_to_last_argument = 0)
+      : base_reg_(base_reg),
+        argument_count_reg_(argument_count_reg),
+        argument_count_immediate_(0),
+        receiver_mode_(receiver_mode),
+        extra_displacement_to_last_argument_(
+            extra_displacement_to_last_argument) { }
+
+  StackArgumentsAccessor(
+      Register base_reg,
+      const ParameterCount& parameter_count,
+      StackArgumentsAccessorReceiverMode receiver_mode =
+          ARGUMENTS_CONTAIN_RECEIVER,
+      int extra_displacement_to_last_argument = 0)
+      : base_reg_(base_reg),
+        argument_count_reg_(parameter_count.is_reg() ?
+                            parameter_count.reg() : no_reg),
+        argument_count_immediate_(parameter_count.is_immediate() ?
+                                  parameter_count.immediate() : 0),
+        receiver_mode_(receiver_mode),
+        extra_displacement_to_last_argument_(
+            extra_displacement_to_last_argument) { }
+
+  Operand GetArgumentOperand(int index);
+  Operand GetReceiverOperand() {
+    ASSERT(receiver_mode_ == ARGUMENTS_CONTAIN_RECEIVER);
+    return GetArgumentOperand(0);;
+  }
+
+ private:
+  const Register base_reg_;
+  const Register argument_count_reg_;
+  const int argument_count_immediate_;
+  const StackArgumentsAccessorReceiverMode receiver_mode_;
+  const int extra_displacement_to_last_argument_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(StackArgumentsAccessor);
+};
+
+
 } }  // namespace v8::internal
 
 #endif  // V8_X64_CODEGEN_X64_H_