Add a HBreak instruction for debugging

src/arm/lithium-arm.cc

 // 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 962 matching lines @@
   // deoptimization environment.
   Representation rep = value->representation();
   HType type = value->type();
   if (rep.IsTagged() && !type.IsSmi() && !type.IsBoolean()) {
     return AssignEnvironment(result);
   }
   return result;
 }
 
 
+LInstruction* LChunkBuilder::DoDebugBreak(HDebugBreak* instr) {
+  return new(zone()) LDebugBreak();
+}
+
 
 LInstruction* LChunkBuilder::DoCompareMap(HCompareMap* instr) {
   ASSERT(instr->value()->representation().IsTagged());
   LOperand* value = UseRegisterAtStart(instr->value());
   LOperand* temp = TempRegister();
   return new(zone()) LCmpMapAndBranch(value, temp);
 }
 
 
 LInstruction* LChunkBuilder::DoArgumentsLength(HArgumentsLength* instr) {
@@ skipping 1611 matching lines @@
 
 
 LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   LOperand* object = UseRegister(instr->object());
   LOperand* index = UseRegister(instr->index());
   return DefineAsRegister(new(zone()) LLoadFieldByIndex(object, index));
 }
 
 
 } }  // namespace v8::internal