Add pointers to a VirtualFrame that keep track of the indexes of register...

src/virtual-frame-arm.h

 // Copyright 2008 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
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   // The index of the base of the expression stack.
   int expression_base_index() const { return local0_index() + local_count_; }
 
   // Convert a frame index into a frame pointer relative offset into the
   // actual stack.
   int fp_relative(int index) const {
     return (frame_pointer_ - index) * kPointerSize;
   }
 
   // Record an occurrence of a register in the virtual frame.  This has the
-  // effect of incrementing both the register's frame-internal reference
-  // count and its external reference count.
-  void Use(Register reg);
+  // effect of incrementing the register's external reference count and
+  // of updating the index of the register's location in the frame.
+  void Use(Register reg, int index);
 
   // Record that a register reference has been dropped from the frame.  This
-  // decrements both the register's internal and external reference counts.
+  // decrements the register's external reference count and invalidates the
+  // index of the register's location in the frame.
   void Unuse(Register reg);
 
   // Spill the element at a particular index---write it to memory if
   // necessary, free any associated register, and forget its value if
   // constant.
   void SpillElementAt(int index);
 
   // Sync the element at a particular index.  If it is a register or
   // constant that disagrees with the value on the stack, write it to memory.
   // Keep the element type as register or constant, and clear the dirty bit.
@@ skipping 61 matching lines @@
 
   bool Equals(VirtualFrame* other);
 
   friend class JumpTarget;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_VIRTUAL_FRAME_ARM_H_