[wasm] Differentiate unnamed and empty names

src/messages.cc

 // Copyright 2011 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/messages.h"
 
 #include "src/api.h"
 #include "src/execution.h"
 #include "src/isolate-inl.h"
 #include "src/keys.h"
@@ skipping 187 matching lines @@
 Handle<Object> CallSite::GetFileName() {
   if (!IsJavaScript()) return isolate_->factory()->null_value();
   Object* script = fun_->shared()->script();
   if (!script->IsScript()) return isolate_->factory()->null_value();
   return Handle<Object>(Script::cast(script)->name(), isolate_);
 }
 
 
 Handle<Object> CallSite::GetFunctionName() {
   if (IsWasm()) {
-    if (wasm_obj_->IsUndefined()) return isolate_->factory()->null_value();
-    // wasm_obj_ can be a String if we generate WASM code directly in a test
-    // case.
-    if (wasm_obj_->IsString()) return wasm_obj_;
-    return wasm::GetWasmFunctionName(Handle<JSObject>::cast(wasm_obj_),
-                                     wasm_func_index_);
+    MaybeHandle<String> name;
+    if (!wasm_obj_->IsUndefined()) {
+      name = wasm::GetWasmFunctionName(Handle<JSObject>::cast(wasm_obj_),
+                                       wasm_func_index_);
+    }
+    if (name.is_null()) return isolate_->factory()->null_value();
+    return name.ToHandleChecked();
   }
   Handle<String> result = JSFunction::GetName(fun_);
   if (result->length() != 0) return result;
 
   Handle<Object> script(fun_->shared()->script(), isolate_);
   if (script->IsScript() &&
       Handle<Script>::cast(script)->compilation_type() ==
           Script::COMPILATION_TYPE_EVAL) {
     return isolate_->factory()->eval_string();
   }
@@ skipping 221 matching lines @@
       builder.AppendCharacter(*c);
     }
   }
 
   return builder.Finish();
 }
 
 
 }  // namespace internal
 }  // namespace v8