[wasm] Differentiate unnamed and empty names

src/frames.cc

Index: src/frames.cc
diff --git a/src/frames.cc b/src/frames.cc
index a8fe6bb7b61b2524c6f84313370ab665b234424e..e1fdb2a7180420eff2eb0f7e0e57ad20846bc703 100644
--- a/src/frames.cc
+++ b/src/frames.cc
@@ -1355,11 +1355,12 @@ uint32_t WasmFrame::function_index() {
   return val;
 }
 
-Object* WasmFrame::function_name() {
+String* WasmFrame::function_name() {
   Object* wasm_object = wasm_obj();
-  if (wasm_object->IsUndefined()) return wasm_object;
+  if (wasm_object->IsUndefined()) return nullptr;
   Handle<JSObject> wasm = handle(JSObject::cast(wasm_object));
-  return *wasm::GetWasmFunctionName(wasm, function_index());
+  MaybeHandle<String> name = wasm::GetWasmFunctionName(wasm, function_index());
+  return name.is_null() ? nullptr : *name.ToHandleChecked();

[Yang, 2016/05/18 13:38:48]

This whole method seems to have only one user. Why don't we simply compute the
name at the callsite from wasm_object() and function_index(). JavaScriptFrame
doesn't offer this functionality either.

[Clemens Hammacher, 2016/05/18 17:44:06]

Makes sense. Done.

 }
 
 namespace {