5d875a57fa
The previous hack with HInstanceOfKnownGlobal was not only slower, but also very brittle and required a lot of weird hacks to support it. And what's even more important it wasn't even correct (because a map check on the lhs is never enough for instanceof). The new implementation provides a sane runtime implementation for InstanceOf plus a fast case in the InstanceOfStub, combined with a proper specialization in the case of a known global in CrankShaft, which does only the prototype chain walk (coupled with a code dependency on the known global). As a drive-by-fix: Also fix the incorrect Object.prototype.isPrototypeOf implementation. BUG=v8:4376 LOG=y Review URL: https://codereview.chromium.org/1304633002 Cr-Commit-Position: refs/heads/master@{#30342}
11 lines
317 B
JavaScript
11 lines
317 B
JavaScript
// Copyright 2015 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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function Foo() {}
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var x = new Foo();
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function foo() { return x instanceof Foo; }
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assertTrue(foo());
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Foo.prototype = 1;
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assertThrows(foo, TypeError);
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