59 lines
1.9 KiB
JavaScript
59 lines
1.9 KiB
JavaScript
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// 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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// Flags: --allow-natives-syntax
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function Migrator(o) {
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return o.foo;
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}
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function Loader(o) {
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return o[0];
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}
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var first_smi_array = [1];
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var second_smi_array = [2];
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var first_object_array = ["first"];
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var second_object_array = ["string"];
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assertTrue(%HasFastSmiElements(first_smi_array));
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assertTrue(%HasFastSmiElements(second_smi_array));
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assertTrue(%HasFastObjectElements(first_object_array));
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assertTrue(%HasFastObjectElements(second_object_array));
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// Prepare identical transition chains for smi and object arrays.
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first_smi_array.foo = 0;
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second_smi_array.foo = 0;
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first_object_array.foo = 0;
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second_object_array.foo = 0;
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// Collect type feedback for not-yet-deprecated original object array map.
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for (var i = 0; i < 3; i++) Migrator(second_object_array);
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// Blaze a migration trail for smi array maps.
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// This marks the migrated smi array map as a migration target.
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first_smi_array.foo = 0.5;
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print(second_smi_array.foo);
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// Deprecate original object array map.
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// Use TryMigrate from deferred optimized code to migrate second object array.
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first_object_array.foo = 0.5;
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%OptimizeFunctionOnNextCall(Migrator);
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Migrator(second_object_array);
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// |second_object_array| now erroneously has a smi map.
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// Optimized code assuming smi elements will expose this.
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for (var i = 0; i < 3; i++) Loader(second_smi_array);
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%OptimizeFunctionOnNextCall(Loader);
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assertEquals("string", Loader(second_object_array));
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// Any of the following checks will also fail:
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assertTrue(%HasFastObjectElements(second_object_array));
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assertFalse(%HasFastSmiElements(second_object_array));
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assertTrue(%HaveSameMap(first_object_array, second_object_array));
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assertFalse(%HaveSameMap(first_smi_array, second_object_array));
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%ClearFunctionTypeFeedback(Loader);
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%ClearFunctionTypeFeedback(Migrator);
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