// Copyright 2015 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. function Receiver() { this.receiver = "receiver"; } function Proto() { this.proto = "proto"; } function f(a) { return a.foo; } var rec = new Receiver(); // Formerly, this mutated rec.__proto__.__proto__, but // the global object prototype chain is now immutable; // not sure if this test now hits the original hazard case. var proto = rec.__proto__; // Initialize prototype chain dependent IC (nonexistent load). assertEquals(undefined, f(rec)); assertEquals(undefined, f(rec)); // Add a new prototype to the end of the chain. var p2 = new Proto(); p2.__proto__ = null; proto.__proto__ = p2; // Update the IC. assertEquals(undefined, f(rec)); // Now modify the most recently added prototype by adding a property... p2.foo = "bar"; assertEquals("bar", f(rec)); // ...and removing it again. Due to missing prototype user registrations, // this fails to invalidate the IC. delete p2.foo; p2.secret = "GAME OVER"; assertEquals(undefined, f(rec));