[stubs] Introduce ToNameStub to implement %_ToName.

src/crankshaft/hydrogen.cc

Index: src/crankshaft/hydrogen.cc
diff --git a/src/crankshaft/hydrogen.cc b/src/crankshaft/hydrogen.cc
index 0fa2df566d556ec94ca0a49e1b13b5dc1b0cc4be..36107aca06056d03b201e4cfb7da4355be319692 100644
--- a/src/crankshaft/hydrogen.cc
+++ b/src/crankshaft/hydrogen.cc
@@ -12291,6 +12291,30 @@ void HOptimizedGraphBuilder::GenerateToInteger(CallRuntime* call) {
 }
 
 
+void HOptimizedGraphBuilder::GenerateToName(CallRuntime* call) {
+  DCHECK_EQ(1, call->arguments()->length());
+  CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
+  HValue* input = Pop();
+  if (input->type().IsSmi()) {
+    HValue* result = BuildNumberToString(input, Type::SignedSmall(zone()));
+    return ast_context()->ReturnValue(result);
+  } else if (input->type().IsTaggedNumber()) {
+    HValue* result = BuildNumberToString(input, Type::Number(zone()));
+    return ast_context()->ReturnValue(result);
+  } else if (input->type().IsString()) {
+    return ast_context()->ReturnValue(input);
+  } else {
+    Callable callable = CodeFactory::ToName(isolate());
+    HValue* stub = Add<HConstant>(callable.code());
+    HValue* values[] = {context(), input};
+    HInstruction* result =
+        New<HCallWithDescriptor>(stub, 0, callable.descriptor(),
+                                 Vector<HValue*>(values, arraysize(values)));
+    return ast_context()->ReturnInstruction(result, call->id());
+  }
+}
+
+
 void HOptimizedGraphBuilder::GenerateToObject(CallRuntime* call) {
   DCHECK_EQ(1, call->arguments()->length());
   CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
@@ -12303,11 +12327,11 @@ void HOptimizedGraphBuilder::GenerateToObject(CallRuntime* call) {
 void HOptimizedGraphBuilder::GenerateToString(CallRuntime* call) {
   DCHECK_EQ(1, call->arguments()->length());
   CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
-  Callable callable = CodeFactory::ToString(isolate());
   HValue* input = Pop();
   if (input->type().IsString()) {
     return ast_context()->ReturnValue(input);
   } else {
+    Callable callable = CodeFactory::ToString(isolate());
     HValue* stub = Add<HConstant>(callable.code());
     HValue* values[] = {context(), input};
     HInstruction* result =