Add a HBreak instruction for debugging

src/arm/lithium-arm.h

 // Copyright 2012 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 71 matching lines @@
   V(ClassOfTestAndBranch)                       \
   V(CmpConstantEqAndBranch)                     \
   V(CmpIDAndBranch)                             \
   V(CmpObjectEqAndBranch)                       \
   V(CmpMapAndBranch)                            \
   V(CmpT)                                       \
   V(ConstantD)                                  \
   V(ConstantI)                                  \
   V(ConstantT)                                  \
   V(Context)                                    \
+  V(DebugBreak)                                 \
   V(DeclareGlobals)                             \
   V(DeleteProperty)                             \
   V(Deoptimize)                                 \
   V(DivI)                                       \
   V(DoubleToI)                                  \
   V(DummyUse)                                   \
   V(ElementsKind)                               \
   V(FixedArrayBaseLength)                       \
   V(FunctionLiteral)                            \
   V(GetCachedArrayIndex)                        \
@@ skipping 586 matching lines @@
   }
 
   LOperand* minuend() { return inputs_[0]; }
   LOperand* multiplier() { return inputs_[1]; }
   LOperand* multiplicand() { return inputs_[2]; }
 
   DECLARE_CONCRETE_INSTRUCTION(MultiplySubD, "multiply-sub-d")
 };
 
 
+class LDebugBreak: public LTemplateInstruction<0, 0, 0> {
+ public:
+  DECLARE_CONCRETE_INSTRUCTION(DebugBreak, "break")
+};
+
+
 class LCmpIDAndBranch: public LControlInstruction<2, 0> {
  public:
   LCmpIDAndBranch(LOperand* left, LOperand* right) {
     inputs_[0] = left;
     inputs_[1] = right;
   }
 
   LOperand* left() { return inputs_[0]; }
   LOperand* right() { return inputs_[1]; }
 
@@ skipping 2105 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(LChunkBuilder);
 };
 
 #undef DECLARE_HYDROGEN_ACCESSOR
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_LITHIUM_ARM_H_