ES6: Implement Object.setPrototypeOf

src/v8natives.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 997 matching lines @@
 
 
 // ES5 section 15.2.3.2.
 function ObjectGetPrototypeOf(obj) {
   if (!IS_SPEC_OBJECT(obj)) {
     throw MakeTypeError("called_on_non_object", ["Object.getPrototypeOf"]);
   }
   return %GetPrototype(obj);
 }
 
+// ES6 section 19.1.2.19.
+function ObjectSetPrototypeOf(obj, proto) {
+  if (IS_NULL_OR_UNDEFINED(obj) && !IS_UNDETECTABLE(obj)) {

[arv (Not doing code reviews), 2014/01/17 17:43:23]

The ES6 spec uses CheckObjectCoercible. It comes up in a few places so maybe we
should add new macro for this?

CHECK_OBJECT_COERCIBLE(obj, 'Object.setPrototypeOf')

which would throw the required type error.

[Dmitry Lomov (no reviews), 2014/01/17 20:17:36]

 Agreed, good idea.

+    throw MakeTypeError("called_on_null_or_undefined",
+                        ["Object.setPrototypeOf"]);
+  }
+
+  if (proto !== null && !IS_SPEC_OBJECT(proto)) {
+    throw MakeTypeError("proto_object_or_null", [proto]);
+  }
+
+  if (IS_SPEC_OBJECT(obj)) {
+    %SetPrototype(obj, proto);
+  }
+
+  return obj;
+}
+
 
 // ES5 section 15.2.3.3
 function ObjectGetOwnPropertyDescriptor(obj, p) {
   if (!IS_SPEC_OBJECT(obj)) {
     throw MakeTypeError("called_on_non_object",
                         ["Object.getOwnPropertyDescriptor"]);
   }
   var desc = GetOwnProperty(obj, p);
   return FromPropertyDescriptor(desc);
 }
@@ skipping 408 matching lines @@
                       ObjectGetProto, ObjectSetProto);
 
   // Set up non-enumerable functions in the Object object.
   InstallFunctions($Object, DONT_ENUM, $Array(
     "keys", ObjectKeys,
     "create", ObjectCreate,
     "defineProperty", ObjectDefineProperty,
     "defineProperties", ObjectDefineProperties,
     "freeze", ObjectFreeze,
     "getPrototypeOf", ObjectGetPrototypeOf,
+    "setPrototypeOf", ObjectSetPrototypeOf,
     "getOwnPropertyDescriptor", ObjectGetOwnPropertyDescriptor,
     "getOwnPropertyNames", ObjectGetOwnPropertyNames,
     // getOwnPropertySymbols is added in symbol.js.
     "is", ObjectIs,
     "isExtensible", ObjectIsExtensible,
     "isFrozen", ObjectIsFrozen,
     "isSealed", ObjectIsSealed,
     "preventExtensions", ObjectPreventExtension,
     "seal", ObjectSeal
     // deliverChangeRecords, getNotifier, observe and unobserve are added
@@ skipping 432 matching lines @@
 // Eventually, we should move to a real event queue that allows to maintain
 // relative ordering of different kinds of tasks.
 
 RunMicrotasks.runners = new InternalArray;
 
 function RunMicrotasks() {
   while (%SetMicrotaskPending(false)) {
     for (var i in RunMicrotasks.runners) RunMicrotasks.runners[i]();
   }
 }