Make Object::ToObject() output more useful error messages

This allows us to avoid a separate receiver typecheck in a few places
without regressing the error messages generated.

As more Array methods move to C++, this will get more usage.

Bug: v8:3577
Change-Id: Ibdd17c781548520172ce62442bc3a800e5c09e99
Reviewed-on: https://chromium-review.googlesource.com/486103Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Commit-Queue: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44904}

src/builtins/builtins-array.cc

@@ -1206,15 +1206,9 @@ BUILTIN(ArrayConcat) {
   HandleScope scope(isolate);
 
   Handle<Object> receiver = args.receiver();
-  // TODO(bmeurer): Do we really care about the exact exception message here?
-  if (receiver->IsNullOrUndefined(isolate)) {
-    THROW_NEW_ERROR_RETURN_FAILURE(
-        isolate, NewTypeError(MessageTemplate::kCalledOnNullOrUndefined,
-                              isolate->factory()->NewStringFromAsciiChecked(
-                                  "Array.prototype.concat")));
-  }
   ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
-      isolate, receiver, Object::ToObject(isolate, args.receiver()));
+      isolate, receiver,
+      Object::ToObject(isolate, args.receiver(), "Array.prototype.concat"));
   args[0] = *receiver;
 
   Handle<JSArray> result_array;

src/objects-inl.h

@@ -1121,9 +1121,10 @@ bool Object::ToUint32(uint32_t* value) {
 
 // static
 MaybeHandle<JSReceiver> Object::ToObject(Isolate* isolate,
-                                         Handle<Object> object) {
+                                         Handle<Object> object,
+                                         const char* method_name) {
   if (object->IsJSReceiver()) return Handle<JSReceiver>::cast(object);
-  return ToObject(isolate, object, isolate->native_context());
+  return ToObject(isolate, object, isolate->native_context(), method_name);
 }
 
 

src/objects.cc

@@ -108,10 +108,10 @@ Handle<FieldType> Object::OptimalType(Isolate* isolate,
   return FieldType::Any(isolate);
 }
 
-
 MaybeHandle<JSReceiver> Object::ToObject(Isolate* isolate,
                                          Handle<Object> object,
-                                         Handle<Context> native_context) {
+                                         Handle<Context> native_context,
+                                         const char* method_name) {
   if (object->IsJSReceiver()) return Handle<JSReceiver>::cast(object);
   Handle<JSFunction> constructor;
   if (object->IsSmi()) {
@@ -120,6 +120,14 @@ MaybeHandle<JSReceiver> Object::ToObject(Isolate* isolate,
     int constructor_function_index =
         Handle<HeapObject>::cast(object)->map()->GetConstructorFunctionIndex();
     if (constructor_function_index == Map::kNoConstructorFunctionIndex) {
+      if (method_name != nullptr) {
+        THROW_NEW_ERROR(
+            isolate,
+            NewTypeError(
+                MessageTemplate::kCalledOnNullOrUndefined,
+                isolate->factory()->NewStringFromAsciiChecked(method_name)),
+            JSReceiver);
+      }
       THROW_NEW_ERROR(isolate,
                       NewTypeError(MessageTemplate::kUndefinedOrNullToObject),
                       JSReceiver);

src/objects.h

@@ -1234,12 +1234,19 @@ class Object {
   // ES6 section 7.2.13 Strict Equality Comparison
   bool StrictEquals(Object* that);
 
+  // ES6 section 7.1.13 ToObject
   // Convert to a JSObject if needed.
   // native_context is used when creating wrapper object.
+  //
+  // Passing a non-null method_name allows us to give a more informative
+  // error message for those cases where ToObject is being called on
+  // the receiver of a built-in method.
   MUST_USE_RESULT static inline MaybeHandle<JSReceiver> ToObject(
-      Isolate* isolate, Handle<Object> object);
+      Isolate* isolate, Handle<Object> object,
+      const char* method_name = nullptr);
   MUST_USE_RESULT static MaybeHandle<JSReceiver> ToObject(
-      Isolate* isolate, Handle<Object> object, Handle<Context> context);
+      Isolate* isolate, Handle<Object> object, Handle<Context> native_context,
+      const char* method_name = nullptr);
 
   // ES6 section 9.2.1.2, OrdinaryCallBindThis for sloppy callee.
   MUST_USE_RESULT static MaybeHandle<JSReceiver> ConvertReceiver(

src/runtime/runtime-array.cc

@@ -531,16 +531,10 @@ RUNTIME_FUNCTION(Runtime_ArrayIndexOf) {
   CONVERT_ARG_HANDLE_CHECKED(Object, from_index, 2);
 
   // Let O be ? ToObject(this value).
-  Handle<Object> receiver_obj = args.at(0);
-  if (receiver_obj->IsNullOrUndefined(isolate)) {
-    THROW_NEW_ERROR_RETURN_FAILURE(
-        isolate, NewTypeError(MessageTemplate::kCalledOnNullOrUndefined,
-                              isolate->factory()->NewStringFromAsciiChecked(
-                                  "Array.prototype.indexOf")));
-  }
   Handle<JSReceiver> object;
-  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, object,
-                                     Object::ToObject(isolate, args.at(0)));
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+      isolate, object,
+      Object::ToObject(isolate, args.at(0), "Array.prototype.indexOf"));
 
   // Let len be ? ToLength(? Get(O, "length")).
   int64_t len;