[wasm] Differentiate unnamed and empty names

test/cctest/wasm/test-wasm-function-name-table.cc

Index: test/cctest/wasm/test-wasm-function-name-table.cc
diff --git a/test/cctest/wasm/test-wasm-function-name-table.cc b/test/cctest/wasm/test-wasm-function-name-table.cc
index f3285df1b76013e355202e4e55d22fa86922a9e8..53c17f50ff63a43d0d8cd140e7ecc557691f9ad7 100644
--- a/test/cctest/wasm/test-wasm-function-name-table.cc
+++ b/test/cctest/wasm/test-wasm-function-name-table.cc
@@ -30,10 +30,13 @@ void testFunctionNameTable(Vector<Vector<const char>> names) {
 
   WasmModule module;
   std::vector<char> all_names;
+  // No name should have offset 0, because that encodes unnamed functions.
+  // In real wasm binary, offset 0 is impossible anyway.
+  all_names.push_back('\0');
 
   uint32_t func_index = 0;
   for (Vector<const char> name : names) {
-    size_t name_offset = all_names.size();
+    size_t name_offset = name.start() ? all_names.size() : 0;
     all_names.insert(all_names.end(), name.start(),
                      name.start() + name.length());
     // Make every second function name null-terminated.
@@ -56,16 +59,21 @@ void testFunctionNameTable(Vector<Vector<const char>> names) {
     Handle<Object> string_obj = GetWasmFunctionNameFromTable(
         Handle<ByteArray>::cast(wasm_function_name_table), func_index);
     CHECK(!string_obj.is_null());
-    CHECK(string_obj->IsString());
-    Handle<String> string = Handle<String>::cast(string_obj);
-    CHECK(string->IsUtf8EqualTo(name));
+    if (name.start()) {
+      CHECK(string_obj->IsString());
+      Handle<String> string = Handle<String>::cast(string_obj);
+      CHECK(string->IsUtf8EqualTo(name));
+    } else {
+      CHECK(string_obj->IsNull());
+    }
     ++func_index;
   }
 }
 
 void testFunctionNameTable(Vector<const char *> names) {
   std::vector<Vector<const char>> names_vec;
-  for (const char *name : names) names_vec.push_back(CStrVector(name));
+  for (const char *name : names)
+    names_vec.push_back(name ? CStrVector(name) : Vector<const char>());
   testFunctionNameTable(Vector<Vector<const char>>(
       names_vec.data(), static_cast<int>(names_vec.size())));
 }
@@ -108,3 +116,8 @@ TEST(UTF8Names) {
   const char *names[] = {"↱fun↰", "↺", "alpha:α beta:β"};
   testFunctionNameTable(ArrayVector(names));
 }
+
+TEST(UnnamesVsEmptyNames) {
+  const char *names[] = {"", nullptr, nullptr, ""};
+  testFunctionNameTable(ArrayVector(names));
+}