[MIPS] Forbid $sp update at the end of the last bundle.

src/trusted/validator_mips/model.h

 /*
  * Copyright 2012 The Native Client Authors.  All rights reserved.
  * Use of this source code is governed by a BSD-style license that can
  * be found in the LICENSE file.
  * Copyright 2012, Google Inc.
  */
 
 #ifndef NATIVE_CLIENT_SRC_TRUSTED_VALIDATOR_MIPS_MODEL_H
 #define NATIVE_CLIENT_SRC_TRUSTED_VALIDATOR_MIPS_MODEL_H
 
@@ skipping 135 matching lines @@
   inline uint32_t operator&(uint32_t) const;
 
  private:
   uint32_t _bits;
 };
 
 uint32_t const kInstrSize   = 4;
 uint32_t const kInstrAlign  = 0xFFFFFFFC;
 uint32_t const kBundleAlign = 0xFFFFFFF0;
 
+// Opcode for nop instruction.
+uint32_t const kNop = 0x0;
+
 }  // namespace
 
 // Definitions for our inlined functions.
 #include "native_client/src/trusted/validator_mips/model-inl.h"
 
 #endif  // NATIVE_CLIENT_SRC_TRUSTED_VALIDATOR_MIPS_MODEL_H