Robert Nystrom
fc1b1ecc71
Change-Id: Idbcc965a27e9ffeedf5e0a1068b019de4193070f Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/127745 Commit-Queue: Bob Nystrom <rnystrom@google.com> Reviewed-by: Alexander Thomas <athom@google.com>
58 lines
1.6 KiB
Dart
58 lines
1.6 KiB
Dart
// Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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// Regression test for dart2js that used to generate wrong code for
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// it. The bug happened in the SSA type propagation.
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class A {
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next() => new B();
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doIt() => null;
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bool get isEmpty => false;
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foo() => 42;
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bar() => 54;
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}
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bool entered = false;
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class B extends A {
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foo() => 54;
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doIt() => new A();
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bool get isEmpty => true;
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bar() => entered = true;
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}
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// (1) At initialization phase of the type propagation, [a] would be
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// marked as [exact A].
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// (2) Will make the loop phi [b] typed [null, exact A].
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// (3) Will create a [HTypeKnown] [exact A] for [b].
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// (4) Will create a [HTypeKnown] [exact A] for [b] and update users
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// of [b] to use this [HTypeKnown] instead.
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// (5) [a] will be updated to [subclass A].
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// (6) Will change the [HTypeKnown] of [b] from [exact A] to [subclass A].
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// (7) Receiver is [subclass A] and it will refine it to
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// [subclass A]. We used to wrongly assume there was
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// no need to update the [HTypeKnown] created in (3).
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// (8) Consider that bar is called on an [exact A] (the [HTypeKnown]
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// created in (3)) and remove the call because it does not have
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// any side effects.
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main() {
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var a = new A();
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for (var i in [42]) {
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a = a.next();
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}
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// (1, 5)
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var b = a;
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while (b.isEmpty) {
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// (4, 6)
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b.foo(); // (3, 7)
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b.bar(); // (8)
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b = b.doIt(); // (2)
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}
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if (!entered) throw 'Test failed';
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}
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