Unifying the handling of storing and loading from safepoint stack

src/x64/macro-assembler-x64.h

 // 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 153 matching lines @@
   // argument in register rsi.
   void LeaveExitFrame(bool save_doubles = false);
 
   // Leave the current exit frame. Expects/provides the return value in
   // register rax (untouched).
   void LeaveApiExitFrame();
 
   // Push and pop the registers that can hold pointers.
   void PushSafepointRegisters() { Pushad(); }
   void PopSafepointRegisters() { Popad(); }
-  static int SafepointRegisterStackIndex(int reg_code) {
-    return kNumSafepointRegisters - 1 -
-        kSafepointPushRegisterIndices[reg_code];
-  }
+  // Store the value in register src in the safepoint register stack
+  // slot for register dst.
+  void StoreToSafepointRegisterSlot(Register dst, Register src);
 
 
   // ---------------------------------------------------------------------------
   // JavaScript invokes
 
   // Invoke the JavaScript function code by either calling or jumping.
   void InvokeCode(Register code,
                   const ParameterCount& expected,
                   const ParameterCount& actual,
                   InvokeFlag flag,
@@ skipping 840 matching lines @@
   // Update allocation top with value in result_end register.
   // If scratch is valid, it contains the address of the allocation top.
   void UpdateAllocationTopHelper(Register result_end, Register scratch);
 
   // Helper for PopHandleScope.  Allowed to perform a GC and returns
   // NULL if gc_allowed.  Does not perform a GC if !gc_allowed, and
   // possibly returns a failure object indicating an allocation failure.
   Object* PopHandleScopeHelper(Register saved,
                                Register scratch,
                                bool gc_allowed);
+
+
+  // Compute memory operands for safepoint stack slots.
+  Operand SafepointRegisterSlot(Register reg);
+  static int SafepointRegisterStackIndex(int reg_code) {
+    return kNumSafepointRegisters - kSafepointPushRegisterIndices[reg_code] - 1;
+  }
+
+  // Needs access to SafepointRegisterStackIndex for optimized frame
+  // traversal.
+  friend class OptimizedFrame;
 };
 
 
 // The code patcher is used to patch (typically) small parts of code e.g. for
 // debugging and other types of instrumentation. When using the code patcher
 // the exact number of bytes specified must be emitted. Is not legal to emit
 // relocation information. If any of these constraints are violated it causes
 // an assertion.
 class CodePatcher {
  public:
@@ skipping 785 matching lines @@
       Jump(adaptor, RelocInfo::CODE_TARGET);
     }
     bind(&invoke);
   }
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_MACRO_ASSEMBLER_X64_H_