MIPS: Reland and fix r21225 and r21226.

src/mips/macro-assembler-mips.h

 // Copyright 2012 the V8 project 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 V8_MIPS_MACRO_ASSEMBLER_MIPS_H_
 #define V8_MIPS_MACRO_ASSEMBLER_MIPS_H_
 
 #include "assembler.h"
 #include "mips/assembler-mips.h"
 #include "v8globals.h"
@@ skipping 1468 matching lines @@
                           DoubleRegister temp_double_reg);
 
 
   void LoadInstanceDescriptors(Register map, Register descriptors);
   void EnumLength(Register dst, Register map);
   void NumberOfOwnDescriptors(Register dst, Register map);
 
   template<typename Field>
   void DecodeField(Register reg) {
     static const int shift = Field::kShift;
-    static const int mask = (Field::kMask >> shift) << kSmiTagSize;
+    static const int mask = Field::kMask >> shift;
     srl(reg, reg, shift);
     And(reg, reg, Operand(mask));
   }
 
   // Generates function and stub prologue code.
   void Prologue(PrologueFrameMode frame_mode);
 
   // Activation support.
   void EnterFrame(StackFrame::Type type);
   void LeaveFrame(StackFrame::Type type);
@@ skipping 151 matching lines @@
 #define CODE_COVERAGE_TOSTRING(x) CODE_COVERAGE_STRINGIFY(x)
 #define __FILE_LINE__ __FILE__ ":" CODE_COVERAGE_TOSTRING(__LINE__)
 #define ACCESS_MASM(masm) masm->stop(__FILE_LINE__); masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 } }  // namespace v8::internal
 
 #endif  // V8_MIPS_MACRO_ASSEMBLER_MIPS_H_