745ae2d8d7
When accessing elements of a global (constant) JSArray, whose backing store is copy-on-write, we can just constant-fold the value and insert a check that the backing store stays the same. Bug: v8:6816, v8:6815 Change-Id: I090bcec7b1ce72a1f9ed8625680ed91e8c67f27f Reviewed-on: https://chromium-review.googlesource.com/662757 Reviewed-by: Yang Guo <yangguo@chromium.org> Commit-Queue: Benedikt Meurer <bmeurer@chromium.org> Cr-Commit-Position: refs/heads/master@{#47963}
36 lines
1.0 KiB
JavaScript
36 lines
1.0 KiB
JavaScript
// Copyright 2017 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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// Flags: --allow-natives-syntax --no-always-opt --opt
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// Check that we properly deoptimize TurboFan'ed code when we constant-fold
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// elements from a COW array and we change the length of the array.
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(function() {
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const a = [1, 2, 3];
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const foo = () => a[0];
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assertEquals(1, foo());
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assertEquals(1, foo());
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%OptimizeFunctionOnNextCall(foo);
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assertEquals(1, foo());
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assertOptimized(foo);
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a.length = 1;
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assertEquals(1, foo());
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assertUnoptimized(foo);
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})();
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// Check that we properly deoptimize TurboFan'ed code when we constant-fold
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// elements from a COW array and we change the element of the array.
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(function() {
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const a = [1, 2, 3];
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const foo = () => a[0];
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assertEquals(1, foo());
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assertEquals(1, foo());
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%OptimizeFunctionOnNextCall(foo);
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assertEquals(1, foo());
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assertOptimized(foo);
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a[0] = 42;
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assertEquals(42, foo());
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assertUnoptimized(foo);
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})();
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