- Allow the use of branch delay slots.

runtime/vm/constants_mips.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_CONSTANTS_MIPS_H_
 #define VM_CONSTANTS_MIPS_H_
 
 namespace dart {
 
 enum Register {
@@ skipping 268 matching lines @@
 
 
 class Instr {
  public:
   enum {
     kInstrSize = 4,
   };
 
   static const int32_t kBreakPointInstruction =
       (SPECIAL << kOpcodeShift) | (BREAK << kFunctionShift);
+  static const int32_t kNopInstruction = 0;
 
   // Get the raw instruction bits.
   inline int32_t InstructionBits() const {
     return reinterpret_cast<int32_t>(this);
   }
 
   // Read one particular bit out of the instruction bits.
   inline int32_t Bit(int nr) const {
     return (InstructionBits() >> nr) & 1;
   }
@@ skipping 46 matching lines @@
   }
 
  private:
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(Instr);
 };
 
 }  // namespace dart
 
 #endif  // VM_CONSTANTS_MIPS_H_