Add a HBreak instruction for debugging

src/mips/lithium-mips.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 190 matching lines @@
   stream->Add("B%d", block_id());
 }
 
 
 void LBranch::PrintDataTo(StringStream* stream) {
   stream->Add("B%d | B%d on ", true_block_id(), false_block_id());
   value()->PrintTo(stream);
 }
 
 
+LInstruction* LChunkBuilder::DoDebugBreak(HDebugBreak* instr) {
+  return new(zone()) LDebugBreak();
+}
+
 void LCmpIDAndBranch::PrintDataTo(StringStream* stream) {
   stream->Add("if ");
   left()->PrintTo(stream);
   stream->Add(" %s ", Token::String(op()));
   right()->PrintTo(stream);
   stream->Add(" then B%d else B%d", true_block_id(), false_block_id());
 }
 
 
 void LIsObjectAndBranch::PrintDataTo(StringStream* stream) {
@@ skipping 2258 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