Add tool to visualize machine code/lithium.

src/lithium-codegen.cc

Index: src/lithium-codegen.cc
diff --git a/src/lithium-codegen.cc b/src/lithium-codegen.cc
index 1917c338873f49d2b89daba7fb0e1489e1bbefd5..19ebe7e516bfe648fe7a131d2edec3fc3de8b777 100644
--- a/src/lithium-codegen.cc
+++ b/src/lithium-codegen.cc
@@ -103,7 +103,13 @@ bool LCodeGenBase::GenerateBody() {
 
     GenerateBodyInstructionPre(instr);
 
-    RecordAndUpdatePosition(instr->position());
+    HValue* value = instr->hydrogen_value();
+    if (value->position() != RelocInfo::kNoPosition) {
+      ASSERT(!graph()->info()->IsOptimizing() ||
+             !FLAG_emit_opt_code_positions ||
+             value->position() != RelocInfo::kNoPosition);
+      RecordAndWritePosition(value->position());
+    }
 
     instr->CompileToNative(codegen);