Stephen Adams
6384eceedc
Late fields start out holding a sentinel value and after they are initialized or assigned, never hold a sentinel value again.
This CL implements some removal of checks and loads based on this monotonic behaviour.
On two large Dart Angular apps, this reduces the number of late-instance-field checks by ~25%.
One app is 0.44% smaller, the other is 0.98% smaller.
The optimization_test.dart no longer forces `--disable-inlining` because that prevents the inlining that exposes the optimization opportunities.
Most tests already use `@pragma('dart2js:noInline')` to prevent inlining where relevant.
Change-Id: I2327a96e69191313ed6c07eabe94aa2962fb2648
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/246881
Reviewed-by: Joshua Litt <joshualitt@google.com>
Commit-Queue: Stephen Adams <sra@google.com>
Reviewed-by: Sigmund Cherem <sigmund@google.com>
72 lines
1.8 KiB
Dart
72 lines
1.8 KiB
Dart
// Copyright (c) 2022, 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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// @dart = 2.17
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/*member: main:**/
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void main() {
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final x1 = XX();
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x1.assignUseBar();
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x1.assignUseFoo();
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x1.useBar();
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x1.useFoo();
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}
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class XX {
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late int foo;
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late final int bar;
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@pragma('dart2js:noInline')
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/*member: XX.useFoo:
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SsaLateFieldOptimizer.pre=[HFieldGet=3,HLateReadCheck=3],
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SsaLateFieldOptimizer.post=[HFieldGet=3,HLateReadCheck=1],
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*/
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void useFoo() {
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use(foo, foo, effect(), foo, foo, effect(), foo, foo);
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}
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@pragma('dart2js:noInline')
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/*member: XX.useBar:
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SsaLateFieldOptimizer.pre=[HFieldGet=3,HLateReadCheck=3],
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SsaLateFieldOptimizer.post=[HFieldGet=1,HLateReadCheck=1],
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*/
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void useBar() {
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use(bar, bar, effect(), bar, bar, effect(), bar, bar);
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}
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@pragma('dart2js:noInline')
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/*member: XX.assignUseFoo:
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SsaLateFieldOptimizer.pre=[HFieldGet=3,HLateReadCheck=3],
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SsaLateFieldOptimizer.post=[HFieldGet=3],
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*/
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void assignUseFoo() {
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foo = 200;
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use(effect(), foo, effect(), foo, foo, effect(), foo, foo);
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}
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@pragma('dart2js:noInline')
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/*member: XX.assignUseBar:
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SsaLateFieldOptimizer.pre=
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[HFieldGet=4,HLateReadCheck=3,HLateWriteOnceCheck=1],
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SsaLateFieldOptimizer.post=[HFieldGet=1,HLateWriteOnceCheck=1],
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*/
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void assignUseBar() {
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bar = 100;
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use(effect(), bar, effect(), bar, bar, effect(), bar, bar);
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}
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@pragma('dart2js:noInline')
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/*member: XX.use:**/
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void use(int a1, int a2, int a3, int a4, int a5, int a6, int a7, int a8) {
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print([a1, a2, a3, a4, a5, a6, a7, a8]);
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}
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@pragma('dart2js:noInline')
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/*member: XX.effect:**/
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int effect() {
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foo++;
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return 0;
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}
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}
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