69 lines
2.7 KiB
JavaScript
69 lines
2.7 KiB
JavaScript
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// Copyright 2012 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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// Flags: --allow-natives-syntax
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// The original problem from the bug: In the example below SMI check for b
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// generated for inlining of equals invocation (marked with (*)) will be hoisted
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// out of the loop across the typeof b === "object" condition and cause an
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// immediate deopt. Another problem here is that no matter how many time we
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// deopt and reopt we will continue to produce the wrong code.
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//
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// The fix is to notice when a deopt and subsequent reopt doesn't find
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// additional type information, indicating that optimistic LICM should be
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// disabled during compilation.
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function eq(a, b) {
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if (typeof b === "object") {
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return b.equals(a); // (*)
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}
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return a === b;
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}
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Object.prototype.equals = function (other) {
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return (this === other);
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};
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function test() {
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for (var i = 0; !eq(i, 10); i++)
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;
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}
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eq({}, {});
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eq({}, {});
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eq(1, 1);
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eq(1, 1);
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test();
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%OptimizeFunctionOnNextCall(test);
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test();
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%OptimizeFunctionOnNextCall(test);
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// Second compilation should have noticed that LICM wasn't a good idea, and now
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// function should no longer deopt when called.
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test();
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assertTrue(2 != %GetOptimizationStatus(test));
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