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Change the default optimization level to -O2 for wasm in release mode. (#162917)

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As per the investigation in
https://github.com/flutter/flutter/issues/162620, we determined that the
soundness we gain from using `-O2` outweighs the perf benefits of `-O4`.
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Jackson Gardner 2025-02-10 13:29:35 -08:00 committed by GitHub
parent c5fbe83809
commit 30b8eb635b
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GPG Key ID: B5690EEEBB952194
2 changed files with 33 additions and 17 deletions
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39
packages/flutter_tools/lib/src/web/compiler_config.dart
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@ -21,15 +21,9 @@ sealed class WebCompilerConfig {
/// Build environment flag for [sourceMaps].
static const String kSourceMapsEnabled = 'SourceMaps';
/// Calculates the optimization level for dart2js/dart2wasm for the given
/// Calculates the optimization level for the compiler for the given
/// build mode.
int optimizationLevelForBuildMode(BuildMode mode) =>
optimizationLevel ??
switch (mode) {
BuildMode.debug => 0,
BuildMode.profile || BuildMode.release => 4,
BuildMode.jitRelease => throw ArgumentError('Invalid build mode for web'),
};
int optimizationLevelForBuildMode(BuildMode mode);
/// The compiler optimization level specified by the user.
///
@ -111,13 +105,15 @@ class JsCompilerConfig extends WebCompilerConfig {
];
@override
int optimizationLevelForBuildMode(BuildMode mode) {
final int level = super.optimizationLevelForBuildMode(mode);
// dart2js optimization level 0 is not well supported. Use
// 1 instead.
return level == 0 ? 1 : level;
}
int optimizationLevelForBuildMode(BuildMode mode) =>
optimizationLevel ??
switch (mode) {
// dart2js optimization level 0 is not well supported. Use
// 1 instead.
BuildMode.debug => 1,
BuildMode.profile || BuildMode.release => 4,
BuildMode.jitRelease => throw ArgumentError('Invalid build mode for web'),
};
/// Arguments to use in the full JS compile, but not CFE-only.
///
@ -163,6 +159,19 @@ class WasmCompilerConfig extends WebCompilerConfig {
@override
CompileTarget get compileTarget => CompileTarget.wasm;
@override
int optimizationLevelForBuildMode(BuildMode mode) =>
optimizationLevel ??
switch (mode) {
BuildMode.debug => 0,
// The optimization level of O2 uses only sound optimizations. We default
// to this level because our web benchmarks have shown that the difference
// between O2 and O4 is marginal enough that we would prefer soundness here.
BuildMode.profile || BuildMode.release => 2,
BuildMode.jitRelease => throw ArgumentError('Invalid build mode for web'),
};
List<String> toCommandOptions(BuildMode buildMode) {
final bool stripSymbols = buildMode == BuildMode.release && stripWasm;
return <String>[

11
packages/flutter_tools/test/general.shard/build_system/targets/web_test.dart
View File

@ -1140,7 +1140,7 @@ void main() {
WebRendererMode.canvaskit,
WebRendererMode.skwasm,
]) {
for (int level = 1; level <= 4; level++) {
for (final int? level in <int?>[null, 0, 1, 2, 3, 4]) {
for (final bool strip in <bool>[true, false]) {
for (final List<String> defines in const <List<String>>[
<String>[],
@ -1151,6 +1151,13 @@ void main() {
test(
'Dart2WasmTarget invokes dart2wasm with renderer=$renderer, -O$level, stripping=$strip, defines=$defines, modeMode=$buildMode sourceMaps=$sourceMaps',
() => testbed.run(() async {
final int expectedLevel =
level ??
switch (buildMode) {
'debug' => 0,
'profile' || 'release' => 2,
_ => throw UnimplementedError(),
};
environment.defines[kBuildMode] = buildMode;
environment.defines[kDartDefines] = encodeDartDefines(defines);
@ -1182,7 +1189,7 @@ void main() {
],
'-DFLUTTER_WEB_CANVASKIT_URL=https://www.gstatic.com/flutter-canvaskit/abcdefghijklmnopqrstuvwxyz/',
'--extra-compiler-option=--depfile=${depFile.absolute.path}',
'-O$level',
'-O$expectedLevel',
if (strip && buildMode == 'release') '--strip-wasm' else '--no-strip-wasm',
if (!sourceMaps) '--no-source-maps',
if (buildMode == 'debug') '--extra-compiler-option=--enable-asserts',