[wasm] Differentiate unnamed and empty names

src/wasm/wasm-function-name-table.h

 // Copyright 2016 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.
 
 #ifndef V8_WASM_FUNCTION_NAME_TABLE_H_
 #define V8_WASM_FUNCTION_NAME_TABLE_H_
 
 #include "src/handles.h"
 #include "src/objects.h"
 
 namespace v8 {
 namespace internal {
 namespace wasm {
 
 // Forward declarations for some WASM data structures.
 struct WasmModule;
 
 // Encode all function names of the WasmModule into one ByteArray.
+// Returns undefined if the array length would not fit in an integer value.
 Handle<Object> BuildFunctionNamesTable(Isolate* isolate, WasmModule* module);
 
-// Extract the function name for the given func_index from the wasm module.
-// Returns undefined if the function index is invalid.
-Handle<Object> GetWasmFunctionNameFromTable(Handle<ByteArray> wasm_names_table,
-                                            uint32_t func_index);
+// Extract the function name for the given func_index from the function name
+// table.
+// Returns a null handle if the respective function is unnamed (not to be
+// confused with empty names) or the function name is not a valid UTF-8 string.
+MaybeHandle<String> GetWasmFunctionNameFromTable(
+    Handle<ByteArray> wasm_names_table, uint32_t func_index);
 
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_WASM_FUNCTION_NAME_TABLE_H_