[wasm] Differentiate unnamed and empty names

src/runtime/runtime-function.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/runtime/runtime-utils.h"
 
 #include "src/accessors.h"
 #include "src/arguments.h"
 #include "src/compiler.h"
 #include "src/frames-inl.h"
@@ skipping 289 matching lines @@
   return function->IsJSBoundFunction()
              ? *JSBoundFunction::ToString(
                    Handle<JSBoundFunction>::cast(function))
              : *JSFunction::ToString(Handle<JSFunction>::cast(function));
 }
 
 RUNTIME_FUNCTION(Runtime_WasmGetFunctionName) {
   HandleScope scope(isolate);
   DCHECK_EQ(2, args.length());
 
-  CONVERT_ARG_HANDLE_CHECKED(JSObject, wasm, 0);
+  CONVERT_ARG_HANDLE_CHECKED(Object, wasm, 0);
   CONVERT_SMI_ARG_CHECKED(func_index, 1);
 
-  return *wasm::GetWasmFunctionName(wasm, func_index);
+  RUNTIME_ASSERT(wasm->IsUndefined() || wasm->IsJSObject());
+  Handle<Object> funName =
+      wasm->IsUndefined()
+          ? wasm
+          : wasm::GetWasmFunctionName(Handle<JSObject>::cast(wasm), func_index);
+  return *funName;
 }
 
 }  // namespace internal
 }  // namespace v8