Turn the NumberToStringStub into a hydrogen stub.

src/code-stubs-hydrogen.cc

Index: src/code-stubs-hydrogen.cc
diff --git a/src/code-stubs-hydrogen.cc b/src/code-stubs-hydrogen.cc
index 0e1c941fd2f19b47bbc16e84f1fab89c9e12617b..d7cf00a0e73538c1aefe2f1c10f95587130f0c7e 100644
--- a/src/code-stubs-hydrogen.cc
+++ b/src/code-stubs-hydrogen.cc
@@ -339,6 +339,19 @@ Handle<Code> ToNumberStub::GenerateCode(Isolate* isolate) {
 
 
 template <>
+HValue* CodeStubGraphBuilder<NumberToStringStub>::BuildCodeStub() {
+  info()->MarkAsSavesCallerDoubles();

[mvstanton, 2013/09/23 09:32:34]

Comment this as to why you are doing it (the runtime call in
BuildNumberToString).

Also, I don't like that we use constant 0,1,2 for parameter numbers. In
ArrayConstructorStubBase, there is code like:

  // Parameters accessed via CodeStubGraphBuilder::GetParameter()
  static const int kConstructor = 0;
  static const int kPropertyCell = 1;

And then GetParameter calls in those stubs use the constants. Could you
similarly define a constant for NumberToStrings parameter?

[Benedikt Meurer, 2013/09/23 10:53:31]

Done.

+
+  return BuildNumberToString(GetParameter(0));
+}
+
+
+Handle<Code> NumberToStringStub::GenerateCode(Isolate* isolate) {
+  return DoGenerateCode(isolate, this);
+}
+
+
+template <>
 HValue* CodeStubGraphBuilder<FastCloneShallowArrayStub>::BuildCodeStub() {
   Factory* factory = isolate()->factory();
   HValue* undefined = graph()->GetConstantUndefined();