A64: Make the Decoder a template

src/a64/decoder-a64.h

 // Copyright 2013 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 124 matching lines @@
   #define DECLARE(A) void Visit##A(Instruction* instr);
   VISITOR_LIST(DECLARE)
   #undef DECLARE
 
  private:
   // Visitors are registered in a list.
   std::list<DecoderVisitor*> visitors_;
 };
 
 
-class Decoder : public DispatchingDecoderVisitor {
+template<typename V>
+class Decoder : public V {
  public:
   Decoder() {}
 
   // Top-level instruction decoder function. Decodes an instruction and calls
   // the visitor functions registered with the Decoder class.
   void Decode(Instruction *instr);
 
  private:
   // Decode the PC relative addressing instruction, and call the corresponding
   // visitors.
@@ skipping 43 matching lines @@
   // Decode the Advanced SIMD (NEON) data processing part of the instruction
   // tree, and call the corresponding visitors.
   // On entry, instruction bits 27:25 = 0x7.
   void DecodeAdvSIMDDataProcessing(Instruction* instr);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_A64_DECODER_A64_H_