Add tool to visualize machine code/lithium.

src/lithium-codegen.cc

 // Copyright 2013 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 85 matching lines @@
 
     if (FLAG_code_comments && instr->HasInterestingComment(codegen)) {
       Comment(";;; <@%d,#%d> %s",
               current_instruction_,
               instr->hydrogen_value()->id(),
               instr->Mnemonic());
     }
 
     GenerateBodyInstructionPre(instr);
 
-    RecordAndUpdatePosition(instr->position());
+    HValue* value = instr->hydrogen_value();
+    if (value->position() != RelocInfo::kNoPosition) {
+      ASSERT(!graph()->info()->IsOptimizing() ||
+             !FLAG_opt_code_positions ||
+             value->position() != RelocInfo::kNoPosition);
+      RecordAndWritePosition(value->position());
+    }
 
     instr->CompileToNative(codegen);
 
     GenerateBodyInstructionPost(instr);
   }
   EnsureSpaceForLazyDeopt(Deoptimizer::patch_size());
   last_lazy_deopt_pc_ = masm()->pc_offset();
   return !is_aborted();
 }
 
@@ skipping 18 matching lines @@
 
 int LCodeGenBase::GetNextEmittedBlock() const {
   for (int i = current_block_ + 1; i < graph()->blocks()->length(); ++i) {
     if (!chunk_->GetLabel(i)->HasReplacement()) return i;
   }
   return -1;
 }
 
 
 } }  // namespace v8::internal