Update ObjectToString to Harmony-draft algorithm

test/cctest/test-api.cc

Index: test/cctest/test-api.cc
diff --git a/test/cctest/test-api.cc b/test/cctest/test-api.cc
index 283bcb8e0d66d869a7faf3751d761b5a3fb5a3c3..a2bb79a5b40617a84890ab3b7a5b87b33257b534 100644
--- a/test/cctest/test-api.cc
+++ b/test/cctest/test-api.cc
@@ -2021,6 +2021,22 @@ void SymbolAccessorSetter(Local<Name> name, Local<Value> value,
   SimpleAccessorSetter(Local<String>::Cast(sym->Name()), value, info);
 }
 
+void SymbolAccessorGetterReturnsDefault(Local<Name> name,
+                          const v8::PropertyCallbackInfo<v8::Value>& info) {
+  CHECK(name->IsSymbol());
+  Local<Symbol> sym = Local<Symbol>::Cast(name);
+  if (sym->Name()->IsUndefined())
+    return;
+  info.GetReturnValue().Set(info.Data());
+}
+
+static void ThrowingSymbolAccessorGetter(
+    Local<Name> name,
+    const v8::PropertyCallbackInfo<v8::Value>& info) {
+  ApiTestFuzzer::Fuzz();

[Dmitry Lomov (no reviews), 2014/10/18 21:24:19]

Why this line?

+  info.GetReturnValue().Set(info.GetIsolate()->ThrowException(name));
+}
+
 void EmptyInterceptorGetter(Local<String> name,
                             const v8::PropertyCallbackInfo<v8::Value>& info) {
 }
@@ -13489,6 +13505,52 @@ THREADED_TEST(ObjectProtoToString) {
   Local<Value> object = v8_compile("new Object()")->Run();
   value = object.As<v8::Object>()->ObjectProtoToString();
   CHECK(value->IsString() && value->Equals(v8_str("[object Object]")));
+
+  // Check that ES6 semantics using @@toStringTag work
+  i::FLAG_harmony_tostring = true;
+  Local<v8::Symbol> toStringTag = v8::Symbol::GetToStringTag(isolate);
+
+#define TEST_TOSTRINGTAG(type, tag, expected) \
+  do { \
+    object = v8_compile("new " #type "()")->Run(); \

[Dmitry Lomov (no reviews), 2014/10/18 21:24:19]

Nit: use CompileRun here

+    object.As<v8::Object>()->Set(toStringTag, v8_str(#tag)); \
+    value = object.As<v8::Object>()->ObjectProtoToString(); \
+    CHECK(value->IsString() && value->Equals( \
+        v8_str("[object " #expected "]"))); \
+  } while (0)
+
+  TEST_TOSTRINGTAG(Array, Object, Object);
+  TEST_TOSTRINGTAG(Object, Arguments, ~Arguments);
+  TEST_TOSTRINGTAG(Object, Array, ~Array);
+  TEST_TOSTRINGTAG(Object, Boolean, ~Boolean);
+  TEST_TOSTRINGTAG(Object, Date, ~Date);
+  TEST_TOSTRINGTAG(Object, Error, ~Error);
+  TEST_TOSTRINGTAG(Object, Function, ~Function);
+  TEST_TOSTRINGTAG(Object, Number, ~Number);
+  TEST_TOSTRINGTAG(Object, RegExp, ~RegExp);
+  TEST_TOSTRINGTAG(Object, String, ~String);
+  TEST_TOSTRINGTAG(Object, Foo, Foo);
+
+#undef TEST_TOSTRINGTAG
+
+  // @@toStringTag getter throws
+  Local<v8::Object> obj = v8::Object::New(isolate);

[Dmitry Lomov (no reviews), 2014/10/18 21:24:19]

Great test, add one more where the getter is actually written in Javascript:

Local<v8::Value> obj = CompileRun(
          "o = {};"
          "Object.defineProperty(o, Symbol.toStringTag, { ... };"
          " o");

so that ObjectProtoToString actually executes some Javascript code.

[caitp (gmail), 2014/10/18 21:27:40]

There's a problem with that --- the bootstrapper didn't load harmony-tostring,
flipping the flag won't make it use the right function. I'm not sure if there's
a way to re-bootstrap mid-test or something.

[caitp (gmail), 2014/10/18 21:35:01]

Er, I mean `Symbol.toStringTag` is not exposed --- I could expose that easily,
but it still wouldn't use the right function --- I guess that doesn't matter for
the runtime tests though

[Dmitry Lomov (no reviews), 2014/10/18 21:45:00]

Ah, I see. Extract the tests for toStringTag into a separate test.
Use UNINITIALIZED_TEST macro for it instead of THREADED_TEST.
 Add 
    FLAG_harmony_tostring = true; 
    CcTest::InitializeVM();
at the beginning of your test.

+  obj->SetAccessor(toStringTag, ThrowingSymbolAccessorGetter);
+  { TryCatch try_catch;
+    value = obj->ObjectProtoToString();
+    CHECK(value.IsEmpty());
+    CHECK(try_catch.HasCaught());
+  }
+
+  // @@toStringTag getter does not throw
+  obj = v8::Object::New(isolate);
+  obj->SetAccessor(toStringTag, SymbolAccessorGetterReturnsDefault,
+                   0, v8_str("Test"));
+  { TryCatch try_catch;
+    value = obj->ObjectProtoToString();
+    CHECK(value->IsString() && value->Equals(v8_str("[object Test]")));
+    CHECK(!try_catch.HasCaught());
+  }
 }