0ff7b4830c
This patch implements "immutable prototype exotic objects" from the ECMAScript spec, which are objects whose __proto__ cannot be changed, but are not otherwise frozen. They are introduced in order to prevent a Proxy from being introduced to the prototype chain of the global object. The API is extended by a SetImmutablePrototype() call in ObjectTemplate, which can be used to vend new immutable prototype objects. Additionally, Object.prototype is an immutable prototype object. In the implementation, a new bit is added to Maps to say whether the prototype is immutable, which is read by SetPrototype. Map transitions to the immutable prototype state are not saved in the transition tree because the main use case is just for the prototype chain of the global object, which there will be only one of per Context, so no need to take up the extra word for a pointer in each full transition tree. BUG=v8:5149 Review-Url: https://codereview.chromium.org/2108203002 Cr-Commit-Position: refs/heads/master@{#37482}
37 lines
1.8 KiB
JavaScript
37 lines
1.8 KiB
JavaScript
// Copyright 2011 the V8 project authors. All rights reserved.
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following
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// disclaimer in the documentation and/or other materials provided
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// with the distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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// See: http://code.google.com/p/v8/issues/detail?id=1403
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a = [];
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assertThrows(() => Object.prototype.__proto__ = { __proto__: null }, TypeError);
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a.shift();
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a = [];
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Array.prototype.__proto__ = { __proto__: null };
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a.shift();
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