Factor out a commonly used code sequence to DropAndMove(Location, Register)

src/fast-codegen.h

 // Copyright 2009 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 42 matching lines @@
 
   void Move(Location destination, Location source);
 
   void Move(Location destination, Register source);
   void Move(Location destination, Slot* source);
   void Move(Location destination, Literal* source);
 
   void Move(Register destination, Location source);
   void Move(Slot* destination, Location source);
 
+  // Drop the TOS, and store source to destination.
+  // If destination is TOS, just overwrite TOS with source.
+  void DropAndMove(Location destination, Register source);
+
   void VisitDeclarations(ZoneList<Declaration*>* declarations);
   Handle<JSFunction> BuildBoilerplate(FunctionLiteral* fun);
   void DeclareGlobals(Handle<FixedArray> pairs);
 
   void SetFunctionPosition(FunctionLiteral* fun);
   void SetReturnPosition(FunctionLiteral* fun);
   void SetStatementPosition(Statement* stmt);
   void SetSourcePosition(int pos);
 
   // AST node visit functions.
 #define DECLARE_VISIT(type) virtual void Visit##type(type* node);
   AST_NODE_LIST(DECLARE_VISIT)
 #undef DECLARE_VISIT
 
   MacroAssembler* masm_;
   FunctionLiteral* function_;
   Handle<Script> script_;
   bool is_eval_;
 
   DISALLOW_COPY_AND_ASSIGN(FastCodeGenerator);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_FAST_CODEGEN_H_