d5c19aa9fc
In the special case of KeyedLoadIC, where the key that is passed in is a Name that is always the same we only checked for identity in both the stub and the TurboFan case, which works fine for symbols and internalized strings, but doesn't really work with non-internalized strings, where the identity check will fail, the runtime will internalize the string, and the IC will then see the original internalized string again and not progress in the feedback lattice. This leads to tricky deoptimization loops in TurboFan and constantly missing ICs. This adds fixes the stub to always try to internalize strings first when the identity check fails and then doing the check again. If the name is not found in the string table we miss, since in that case the string cannot match the previously recorded feedback name (which is always a unique name). In TurboFan we represent this checks with new CheckEqualsSymbol and CheckEqualsInternalizedString operators, which validate the previously recorded feedback, and the CheckEqualsInternalizedString operator does the attempt to internalize the input. Bug: v8:6936, v8:6948, v8:6969 Change-Id: I3f3b4a587c67f00f7c4b60d239eb98a9626fe04a Reviewed-on: https://chromium-review.googlesource.com/730224 Reviewed-by: Toon Verwaest <verwaest@chromium.org> Reviewed-by: Jaroslav Sevcik <jarin@chromium.org> Commit-Queue: Benedikt Meurer <bmeurer@chromium.org> Cr-Commit-Position: refs/heads/master@{#48784}
21 lines
520 B
JavaScript
21 lines
520 B
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 --opt
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var o = {};
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function foo(s) { return o[s]; }
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var s = 'c' + 'c';
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foo(s);
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foo(s);
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%OptimizeFunctionOnNextCall(foo);
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assertEquals(undefined, foo(s));
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assertOptimized(foo);
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assertEquals(undefined, foo('c' + 'c'));
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assertOptimized(foo);
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assertEquals(undefined, foo('ccddeeffgg'.slice(0, 2)));
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assertOptimized(foo);
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