[MIPS] Make validator allow only two load patterns via $t8

src/trusted/validator_mips/model.h

 /*
  * Copyright (c) 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.
  */
 
 #ifndef NATIVE_CLIENT_SRC_TRUSTED_VALIDATOR_MIPS_MODEL_H
 #define NATIVE_CLIENT_SRC_TRUSTED_VALIDATOR_MIPS_MODEL_H
 
 /*
@@ skipping 24 matching lines @@
 
   /*
    * Produces the bitmask used to represent this register.
    */
   inline uint32_t Bitmask() const;
 
   inline bool Equals(const Register &) const;
 
   static const Number kJumpMask       = 14;  // $t6 = holds mask for jr.
   static const Number kLoadStoreMask  = 15;  // $t7 = holds mask for load/store.
-  static const Number kTls            = 24;  // $t8 = holds tls index.
+  static const Number kTls            = 24;  // $t8 = holds address of
+                                             // tls_value1 in NaClThreadContext.
   static const Number kSp             = 29;  // Stack pointer.
 
   static const Number kNone           = 32;
 
   /*
    * A special value used to indicate that a register field is not used.
    * This is specially chosen to ensure that bitmask() == 0, so it can be added
    * to any RegisterList with no effect.
    */
   static Register None() { return Register(kNone); }
@@ skipping 111 matching lines @@
   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
+}  // namespace nacl_mips_dec
 
 // Definitions for our inlined functions.
 #include "native_client/src/trusted/validator_mips/model-inl.h"
 
 #endif  // NATIVE_CLIENT_SRC_TRUSTED_VALIDATOR_MIPS_MODEL_H