Reverts "Disentangle and align `flutter build web --wasm` flags (#143517)" (#143547)

Reverts flutter/flutter#143517

Initiated by: dnfield

Reason for reverting: broke CI, see https://ci.chromium.org/ui/p/flutter/builders/prod/Linux%20web_benchmarks_skwasm/3446/overview

Original PR Author: mkustermann

Reviewed By: {eyebrowsoffire}

This change reverts the following previous change:
Original Description:
* Make `flutter build web` have one option that determins the optimization level: `-O<level>` / `--optimization-level=<level>` => Defaulting to -O4 => Will apply to both dart2js and dart2wasm

* Deprecate `--dart2js-optimization=O<level>`

* Disentagle concept of optimization from concept of static symbols => Add a `--strip-wasm` / `--no-strip-wasm` flag that determins whether static symbols are kept in the resulting wasm file.

* Remove copy&past'ed code in the tests for wasm build tests

* Cleanup some artifacts code, now that we no longer use `wasm-opt` inside flutter tools

dev/devicelab/lib/tasks/web_benchmarks.dart

@@ -34,9 +34,9 @@ Future<TaskResult> runWebBenchmark(WebBenchmarkOptions benchmarkOptions) async {
     await evalFlutter('build', options: <String>[
       'web',
       if (benchmarkOptions.useWasm) ...<String>[
-        '--O4',
         '--wasm',
-        '--no-strip-wasm',
+        '--wasm-opt=debug',
+        '--omit-type-checks',
       ],
       '--dart-define=FLUTTER_WEB_ENABLE_PROFILING=true',
       if (!benchmarkOptions.useWasm) '--web-renderer=${benchmarkOptions.webRenderer}',

packages/flutter_tools/lib/src/artifacts.dart

@@ -44,6 +44,8 @@ enum Artifact {
   dart2jsSnapshot,
   /// The dart snapshot of the dart2wasm compiler.
   dart2wasmSnapshot,
+  /// The wasm-opt binary that ships with the dart-sdk
+  wasmOptBinary,
 
   /// The root of the Linux desktop sources.
   linuxDesktopPath,
@@ -192,6 +194,8 @@ String? _artifactToFileName(Artifact artifact, Platform hostPlatform, [ BuildMod
       return 'dart2js.dart.snapshot';
     case Artifact.dart2wasmSnapshot:
       return 'dart2wasm_product.snapshot';
+    case Artifact.wasmOptBinary:
+      return 'wasm-opt$exe';
     case Artifact.frontendServerSnapshotForEngineDartSdk:
       return 'frontend_server_aot.dart.snapshot';
     case Artifact.linuxDesktopPath:
@@ -562,6 +566,7 @@ class CachedArtifacts implements Artifacts {
       case Artifact.engineDartAotRuntime:
       case Artifact.dart2jsSnapshot:
       case Artifact.dart2wasmSnapshot:
+      case Artifact.wasmOptBinary:
       case Artifact.frontendServerSnapshotForEngineDartSdk:
       case Artifact.constFinder:
       case Artifact.flutterFramework:
@@ -603,6 +608,7 @@ class CachedArtifacts implements Artifacts {
       case Artifact.engineDartAotRuntime:
       case Artifact.dart2jsSnapshot:
       case Artifact.dart2wasmSnapshot:
+      case Artifact.wasmOptBinary:
       case Artifact.frontendServerSnapshotForEngineDartSdk:
       case Artifact.constFinder:
       case Artifact.flutterMacOSFramework:
@@ -662,6 +668,7 @@ class CachedArtifacts implements Artifacts {
       case Artifact.engineDartAotRuntime:
       case Artifact.dart2jsSnapshot:
       case Artifact.dart2wasmSnapshot:
+      case Artifact.wasmOptBinary:
       case Artifact.frontendServerSnapshotForEngineDartSdk:
       case Artifact.icuData:
       case Artifact.isolateSnapshotData:
@@ -701,6 +708,11 @@ class CachedArtifacts implements Artifacts {
           _dartSdkPath(_cache), 'bin', 'snapshots',
           _artifactToFileName(artifact, _platform),
         );
+      case Artifact.wasmOptBinary:
+        return _fileSystem.path.join(
+          _dartSdkPath(_cache), 'bin', 'utils',
+          _artifactToFileName(artifact, _platform),
+        );
       case Artifact.flutterTester:
       case Artifact.vmSnapshotData:
       case Artifact.isolateSnapshotData:
@@ -1027,6 +1039,8 @@ class CachedLocalEngineArtifacts implements Artifacts {
       case Artifact.dart2wasmSnapshot:
       case Artifact.frontendServerSnapshotForEngineDartSdk:
         return _fileSystem.path.join(_getDartSdkPath(), 'bin', 'snapshots', artifactFileName);
+      case Artifact.wasmOptBinary:
+        return _fileSystem.path.join(_getDartSdkPath(), 'bin', 'utils', artifactFileName);
       case Artifact.flutterToolsFileGenerators:
         return _getFileGeneratorsPath();
       case Artifact.flutterPreviewDevice:
@@ -1164,6 +1178,11 @@ class CachedLocalWebSdkArtifacts implements Artifacts {
             _getDartSdkPath(), 'bin', 'snapshots',
             _artifactToFileName(artifact, _platform, mode),
           );
+        case Artifact.wasmOptBinary:
+          return _fileSystem.path.join(
+            _getDartSdkPath(), 'bin', 'utils',
+            _artifactToFileName(artifact, _platform, mode),
+          );
         case Artifact.genSnapshot:
         case Artifact.flutterTester:
         case Artifact.flutterFramework:

packages/flutter_tools/lib/src/commands/build_web.dart

@@ -55,18 +55,6 @@ class BuildWebCommand extends BuildSubCommand {
     usesWebRendererOption();
     usesWebResourcesCdnFlag();
 
-    //
-    // Common compilation options among JavaScript and Wasm
-    //
-    argParser.addOption(
-      'optimization-level',
-      abbr: 'O',
-      help:
-          'Sets the optimization level used for Dart compilation to JavaScript/Wasm.',
-      defaultsTo: '${WebCompilerConfig.kDefaultOptimizationLevel}',
-      allowed: const <String>['1', '2', '3', '4'],
-    );
-
     //
     // JavaScript compilation options
     //
@@ -84,7 +72,8 @@ class BuildWebCommand extends BuildSubCommand {
     );
     argParser.addOption('dart2js-optimization',
       help: 'Sets the optimization level used for Dart compilation to JavaScript. '
-            'Deprecated: Please use "-O=<level>" / "--optimization-level=<level>".',
+          'Valid values range from O1 to O4.',
+      defaultsTo: JsCompilerConfig.kDart2jsDefaultOptimizationLevel,
       allowed: const <String>['O1', 'O2', 'O3', 'O4'],
     );
     argParser.addFlag('dump-info', negatable: false,
@@ -109,9 +98,19 @@ class BuildWebCommand extends BuildSubCommand {
       hide: !featureFlags.isFlutterWebWasmEnabled,
     );
     argParser.addFlag(
-      'strip-wasm',
-      help: 'Whether to strip the resulting wasm file of static symbol names.',
-      defaultsTo: true,
+      'omit-type-checks',
+      help: 'Omit type checks in Wasm output.\n'
+          'Reduces code size and improves performance, but may affect runtime correctness. Use with care.',
+      negatable: false,
+      hide: !featureFlags.isFlutterWebWasmEnabled,
+    );
+    argParser.addOption(
+      'wasm-opt',
+      help:
+          'Optimize output wasm using the Binaryen (https://github.com/WebAssembly/binaryen) tool.',
+      defaultsTo: WasmOptLevel.defaultValue.cliName,
+      allowed: WasmOptLevel.values.map<String>((WasmOptLevel e) => e.cliName),
+      allowedHelp: CliEnum.allowedHelp(WasmOptLevel.values),
       hide: !featureFlags.isFlutterWebWasmEnabled,
     );
   }
@@ -139,13 +138,6 @@ class BuildWebCommand extends BuildSubCommand {
       throwToolExit('"build web" is not currently supported. To enable, run "flutter config --enable-web".');
     }
 
-    final int optimizationLevel = int.parse(stringArg('optimization-level')!);
-
-    final String? dart2jsOptimizationLevelValue = stringArg('dart2js-optimization');
-    final int jsOptimizationLevel =  dart2jsOptimizationLevelValue != null
-        ? int.parse(dart2jsOptimizationLevelValue.substring(1))
-        : optimizationLevel;
-
     final List<WebCompilerConfig> compilerConfigs;
     if (boolArg('wasm')) {
       if (!featureFlags.isFlutterWebWasmEnabled) {
@@ -163,13 +155,13 @@ class BuildWebCommand extends BuildSubCommand {
 
       compilerConfigs = <WebCompilerConfig>[
         WasmCompilerConfig(
-          optimizationLevel: optimizationLevel,
-          stripWasm: boolArg('strip-wasm'),
+          omitTypeChecks: boolArg('omit-type-checks'),
+          wasmOpt: WasmOptLevel.values.byName(stringArg('wasm-opt')!),
           renderer: WebRendererMode.skwasm,
         ),
         JsCompilerConfig(
           csp: boolArg('csp'),
-          optimizationLevel: jsOptimizationLevel,
+          optimizationLevel: stringArg('dart2js-optimization') ?? JsCompilerConfig.kDart2jsDefaultOptimizationLevel,
           dumpInfo: boolArg('dump-info'),
           nativeNullAssertions: boolArg('native-null-assertions'),
           noFrequencyBasedMinification: boolArg('no-frequency-based-minification'),
@@ -183,7 +175,7 @@ class BuildWebCommand extends BuildSubCommand {
       }
       compilerConfigs = <WebCompilerConfig>[JsCompilerConfig(
         csp: boolArg('csp'),
-        optimizationLevel: jsOptimizationLevel,
+        optimizationLevel: stringArg('dart2js-optimization') ?? JsCompilerConfig.kDart2jsDefaultOptimizationLevel,
         dumpInfo: boolArg('dump-info'),
         nativeNullAssertions: boolArg('native-null-assertions'),
         noFrequencyBasedMinification: boolArg('no-frequency-based-minification'),

packages/flutter_tools/lib/src/web/compiler_config.dart

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import '../base/utils.dart';
 import '../convert.dart';
 import 'compile.dart';
 
@@ -11,18 +12,7 @@ enum CompileTarget {
 }
 
 sealed class WebCompilerConfig {
-  const WebCompilerConfig({required this.renderer, required this.optimizationLevel});
-
-  /// The default optimization level for dart2js/dart2wasm.
-  static const int kDefaultOptimizationLevel = 4;
-
-  /// Build environment flag for [optimizationLevel].
-  static const String kOptimizationLevel = 'OptimizationLevel';
-
-  /// The compiler optimization level.
-  ///
-  /// Valid values are O1 (lowest, profile default) to O4 (highest, release default).
-  final int optimizationLevel;
+  const WebCompilerConfig({required this.renderer});
 
   /// Returns which target this compiler outputs (js or wasm)
   CompileTarget get compileTarget;
@@ -30,14 +20,7 @@ sealed class WebCompilerConfig {
 
   String get buildKey;
 
-  Map<String, Object> get buildEventAnalyticsValues => <String, Object>{
-    'optimizationLevel': optimizationLevel,
-  };
-
-
-  Map<String, dynamic> get _buildKeyMap => <String, dynamic>{
-    'optimizationLevel': optimizationLevel,
-  };
+  Map<String, Object> get buildEventAnalyticsValues => <String, Object>{};
 }
 
 /// Configuration for the Dart-to-Javascript compiler (dart2js).
@@ -46,7 +29,7 @@ class JsCompilerConfig extends WebCompilerConfig {
     this.csp = false,
     this.dumpInfo = false,
     this.nativeNullAssertions = false,
-    super.optimizationLevel = WebCompilerConfig.kDefaultOptimizationLevel,
+    this.optimizationLevel = kDart2jsDefaultOptimizationLevel,
     this.noFrequencyBasedMinification = false,
     this.sourceMaps = true,
     super.renderer = WebRendererMode.auto,
@@ -58,10 +41,18 @@ class JsCompilerConfig extends WebCompilerConfig {
     required WebRendererMode renderer,
   }) : this(
           nativeNullAssertions: nativeNullAssertions,
-          optimizationLevel: WebCompilerConfig.kDefaultOptimizationLevel ,
+          optimizationLevel: kDart2jsDefaultOptimizationLevel,
           renderer: renderer,
         );
 
+  /// The default optimization level for dart2js.
+  ///
+  /// Maps to [kDart2jsOptimization].
+  static const String kDart2jsDefaultOptimizationLevel = 'O4';
+
+  /// Build environment flag for [optimizationLevel].
+  static const String kDart2jsOptimization = 'Dart2jsOptimization';
+
   /// Build environment flag for [dumpInfo].
   static const String kDart2jsDumpInfo = 'Dart2jsDumpInfo';
 
@@ -91,6 +82,12 @@ class JsCompilerConfig extends WebCompilerConfig {
   // TODO(kevmoo): consider renaming this to be "positive". Double negatives are confusing.
   final bool noFrequencyBasedMinification;
 
+  /// The compiler optimization level.
+  ///
+  /// Valid values are O1 (lowest, profile default) to O4 (highest, release default).
+  // TODO(kevmoo): consider storing this as an [int] and validating it!
+  final String optimizationLevel;
+
   /// `true` if the JavaScript compiler build should output source maps.
   final bool sourceMaps;
 
@@ -108,7 +105,7 @@ class JsCompilerConfig extends WebCompilerConfig {
   /// Includes the contents of [toSharedCommandOptions].
   List<String> toCommandOptions() => <String>[
         ...toSharedCommandOptions(),
-        '-O$optimizationLevel',
+        '-$optimizationLevel',
         if (dumpInfo) '--dump-info',
         if (noFrequencyBasedMinification) '--no-frequency-based-minification',
         if (csp) '--csp',
@@ -117,11 +114,11 @@ class JsCompilerConfig extends WebCompilerConfig {
   @override
   String get buildKey {
     final Map<String, dynamic> settings = <String, dynamic>{
-      ...super._buildKeyMap,
       'csp': csp,
       'dumpInfo': dumpInfo,
       'nativeNullAssertions': nativeNullAssertions,
       'noFrequencyBasedMinification': noFrequencyBasedMinification,
+      'optimizationLevel': optimizationLevel,
       'sourceMaps': sourceMaps,
     };
     return jsonEncode(settings);
@@ -131,33 +128,79 @@ class JsCompilerConfig extends WebCompilerConfig {
 /// Configuration for the Wasm compiler.
 class WasmCompilerConfig extends WebCompilerConfig {
   const WasmCompilerConfig({
-    super.optimizationLevel = WebCompilerConfig.kDefaultOptimizationLevel,
-    this.stripWasm = true,
+    this.omitTypeChecks = false,
+    this.wasmOpt = WasmOptLevel.defaultValue,
     super.renderer = WebRendererMode.auto,
   });
 
-  /// Build environment for [stripWasm].
-  static const String kStripWasm = 'StripWasm';
+  /// Build environment for [omitTypeChecks].
+  static const String kOmitTypeChecks = 'WasmOmitTypeChecks';
+
+  /// Build environment for [wasmOpt].
+  static const String kRunWasmOpt = 'RunWasmOpt';
+
+  /// If `omit-type-checks` should be passed to `dart2wasm`.
+  final bool omitTypeChecks;
 
-  /// Whether to strip the wasm file of static symbols.
-  final bool stripWasm;
+  /// Run wasm-opt on the resulting module.
+  final WasmOptLevel wasmOpt;
 
   @override
   CompileTarget get compileTarget => CompileTarget.wasm;
 
   List<String> toCommandOptions() {
-    return <String>[
-      '-O$optimizationLevel',
-      '--${stripWasm? 'no-' : ''}name-section',
-    ];
+    // -O1: Optimizes
+    // -O2: Same as -O1 but also minifies (still semantics preserving)
+    // -O3: Same as -O2 but also omits implicit type checks.
+    // -O4: Same as -O3 but also omits explicit type checks.
+    //      (NOTE: This differs from dart2js -O4 semantics atm.)
+
+    // Ortogonal: The name section is always kept by default and we emit it only
+    // in [WasmOptLevel.full] mode (similar to `--strip` of static symbols in
+    // AOT mode).
+    final String level = !omitTypeChecks ? '-O2' : '-O4';
+    return switch (wasmOpt) {
+      WasmOptLevel.none => <String>['-O0'],
+      WasmOptLevel.debug => <String>[level, '--no-minify'],
+      WasmOptLevel.full => <String>[level, '--no-name-section'],
+    };
   }
 
+  @override
+  Map<String, Object> get buildEventAnalyticsValues => <String, Object>{
+        ...super.buildEventAnalyticsValues,
+        kOmitTypeChecks: omitTypeChecks.toString(),
+        kRunWasmOpt: wasmOpt.name,
+      };
+
   @override
   String get buildKey {
     final Map<String, dynamic> settings = <String, dynamic>{
-      ...super._buildKeyMap,
-      'stripWasm': stripWasm,
+      'omitTypeChecks': omitTypeChecks,
+      'wasmOpt': wasmOpt.name,
     };
     return jsonEncode(settings);
   }
+
+}
+
+enum WasmOptLevel implements CliEnum {
+  full,
+  debug,
+  none;
+
+  static const WasmOptLevel defaultValue = WasmOptLevel.full;
+
+  @override
+  String get cliName => name;
+
+  @override
+  String get helpText => switch (this) {
+        WasmOptLevel.none =>
+          'wasm-opt is not run. Fastest build; bigger, slower output.',
+        WasmOptLevel.debug =>
+          'Similar to `${WasmOptLevel.full.name}`, but member names are preserved. Debugging is easier, but size is a bit bigger.',
+        WasmOptLevel.full =>
+          'wasm-opt is run. Build time is slower, but output is smaller and faster.',
+      };
 }

packages/flutter_tools/test/general.shard/artifacts_test.dart

@@ -427,6 +427,13 @@ void main() {
         fileSystem.path.join('/flutter', 'prebuilts', 'linux-x64', 'dart-sdk',
             'bin', 'snapshots', 'dart2js.dart.snapshot'),
       );
+      expect(
+        artifacts.getArtifactPath(
+          Artifact.wasmOptBinary,
+          platform: TargetPlatform.web_javascript),
+        fileSystem.path.join('/flutter', 'prebuilts', 'linux-x64', 'dart-sdk',
+            'bin', 'utils', 'wasm-opt'),
+      );
     });
 
     testWithoutContext('getEngineType', () {

packages/flutter_tools/test/general.shard/build_system/targets/web_test.dart

@@ -615,6 +615,7 @@ void main() {
 
   test('Dart2JSTarget calls dart2js with expected args in release with dart2js optimization override', () => testbed.run(() async {
     environment.defines[kBuildMode] = 'release';
+    environment.defines[JsCompilerConfig.kDart2jsOptimization] = 'O3';
     processManager.addCommand(FakeCommand(
       command: <String>[
         ..._kDart2jsLinuxArgs,
@@ -643,7 +644,7 @@ void main() {
 
     await Dart2JSTarget(
       const JsCompilerConfig(
-        optimizationLevel: 3,
+        optimizationLevel: 'O3',
         sourceMaps: false,
       )
     ).build(environment);
@@ -900,13 +901,47 @@ void main() {
     ProcessManager: () => processManager,
   }));
 
-  for (final WebRendererMode renderer in <WebRendererMode>[WebRendererMode.canvaskit, WebRendererMode.skwasm]) {
-    for (int level = 1; level <= 4; level++) {
-      for (final bool strip in <bool>[true, false]) {
-        for (final List<String> defines in const <List<String>>[<String>[], <String>['FOO=bar', 'BAZ=qux']]) {
-          test('Dart2WasmTarget invokes dart2wasm with renderer=$renderer, -O$level, stripping=$strip, defines=$defines', () => testbed.run(() async {
+  test('Dart2WasmTarget invokes dart2wasm with dart defines', () => testbed.run(() async {
+    environment.defines[kBuildMode] = 'profile';
+    environment.defines[WasmCompilerConfig.kRunWasmOpt] = WasmOptLevel.defaultValue.name;
+    environment.defines[kDartDefines] = encodeDartDefines(<String>['FOO=bar', 'BAZ=qux']);
+
+    final File depFile = environment.buildDir.childFile('dart2wasm.d');
+
+    final File outputJsFile = environment.buildDir.childFile('main.dart.mjs');
+    processManager.addCommand(FakeCommand(
+      command: <String>[
+        ..._kDart2WasmLinuxArgs,
+        '-Ddart.vm.profile=true',
+        '-DFOO=bar',
+        '-DBAZ=qux',
+        '-DFLUTTER_WEB_AUTO_DETECT=false',
+        '-DFLUTTER_WEB_USE_SKIA=true',
+        '--extra-compiler-option=--depfile=${depFile.absolute.path}',
+        '-O2',
+        '--no-name-section',
+        '-o',
+        environment.buildDir.childFile('main.dart.wasm').absolute.path,
+        environment.buildDir.childFile('main.dart').absolute.path,
+      ],
+      onRun: (_) => outputJsFile..createSync()..writeAsStringSync('foo'))
+    );
+
+    await Dart2WasmTarget(
+      const WasmCompilerConfig(
+        renderer: WebRendererMode.canvaskit
+      )
+    ).build(environment);
+
+    expect(outputJsFile.existsSync(), isTrue);
+  }, overrides: <Type, Generator>{
+    ProcessManager: () => processManager,
+  }));
+
+  test('Dart2WasmTarget invokes dart2wasm with omit checks', () => testbed.run(() async {
     environment.defines[kBuildMode] = 'release';
-            environment.defines[kDartDefines] = encodeDartDefines(defines);
+    environment.defines[WasmCompilerConfig.kRunWasmOpt] = WasmOptLevel.defaultValue.name;
+    environment.defines[WasmCompilerConfig.kOmitTypeChecks] = 'true';
 
     final File depFile = environment.buildDir.childFile('dart2wasm.d');
 
@@ -914,24 +949,112 @@ void main() {
     processManager.addCommand(FakeCommand(
       command: <String>[
         ..._kDart2WasmLinuxArgs,
-                if (renderer == WebRendererMode.skwasm) ...<String>[
+        '-Ddart.vm.product=true',
+        '-DFLUTTER_WEB_AUTO_DETECT=false',
+        '-DFLUTTER_WEB_USE_SKIA=true',
+        '--extra-compiler-option=--depfile=${depFile.absolute.path}',
+        '-O4',
+        '--no-name-section',
+        '-o',
+        environment.buildDir.childFile('main.dart.wasm').absolute.path,
+        environment.buildDir.childFile('main.dart').absolute.path,
+      ],
+      onRun: (_) => outputJsFile..createSync()..writeAsStringSync('foo'))
+    );
+
+    await Dart2WasmTarget(
+      const WasmCompilerConfig(
+        omitTypeChecks: true,
+        renderer: WebRendererMode.canvaskit
+      )
+    ).build(environment);
+
+    expect(outputJsFile.existsSync(), isTrue);
+  }, overrides: <Type, Generator>{
+    ProcessManager: () => processManager,
+  }));
+
+  test('Dart2WasmTarget invokes dart2wasm and wasm-opt with debug info in wasmopt debug mode', () => testbed.run(() async {
+    environment.defines[kBuildMode] = 'release';
+    environment.defines[WasmCompilerConfig.kRunWasmOpt] = WasmOptLevel.debug.name;
+
+    final File depFile = environment.buildDir.childFile('dart2wasm.d');
+
+    final File outputJsFile = environment.buildDir.childFile('main.dart.mjs');
+    processManager.addCommand(FakeCommand(
+      command: <String>[
+        ..._kDart2WasmLinuxArgs,
+        '-Ddart.vm.product=true',
+        '-DFLUTTER_WEB_AUTO_DETECT=false',
+        '-DFLUTTER_WEB_USE_SKIA=true',
+        '--extra-compiler-option=--depfile=${depFile.absolute.path}',
+        '-O2',
+        '--no-minify',
+        '-o',
+        environment.buildDir.childFile('main.dart.wasm').absolute.path,
+        environment.buildDir.childFile('main.dart').absolute.path,
+      ], onRun: (_) => outputJsFile..createSync()..writeAsStringSync('foo')));
+
+    await Dart2WasmTarget(
+      const WasmCompilerConfig(
+        wasmOpt: WasmOptLevel.debug,
+        renderer: WebRendererMode.canvaskit
+      )
+    ).build(environment);
+
+    expect(outputJsFile.existsSync(), isTrue);
+  }, overrides: <Type, Generator>{
+    ProcessManager: () => processManager,
+  }));
+
+  test('Dart2WasmTarget invokes dart2wasm (but not wasm-opt) with wasm-opt none option', () => testbed.run(() async {
+    environment.defines[kBuildMode] = 'debug';
+    environment.defines[WasmCompilerConfig.kRunWasmOpt] = WasmOptLevel.none.name;
+
+    final File depFile = environment.buildDir.childFile('dart2wasm.d');
+
+    final File outputJsFile = environment.buildDir.childFile('main.dart.mjs');
+    processManager.addCommand(FakeCommand(
+      command: <String>[
+        ..._kDart2WasmLinuxArgs,
+        '-Ddart.vm.product=true',
+        '-DFLUTTER_WEB_AUTO_DETECT=false',
+        '-DFLUTTER_WEB_USE_SKIA=true',
+        '--extra-compiler-option=--depfile=${depFile.absolute.path}',
+        '-O0',
+        '-o',
+        environment.buildDir.childFile('main.dart.wasm').absolute.path,
+        environment.buildDir.childFile('main.dart').absolute.path,
+      ], onRun: (_) => outputJsFile..createSync()..writeAsStringSync('foo')));
+
+    await Dart2WasmTarget(
+      const WasmCompilerConfig(
+        wasmOpt: WasmOptLevel.none,
+        renderer: WebRendererMode.canvaskit
+      )
+    ).build(environment);
+  }, overrides: <Type, Generator>{
+    ProcessManager: () => processManager,
+  }));
+
+  test('Dart2WasmTarget with skwasm renderer adds extra flags', () => testbed.run(() async {
+    environment.defines[kBuildMode] = 'release';
+    environment.defines[WasmCompilerConfig.kRunWasmOpt] = WasmOptLevel.defaultValue.name;
+    final File depFile = environment.buildDir.childFile('dart2wasm.d');
+
+    final File outputJsFile = environment.buildDir.childFile('main.dart.mjs');
+    processManager.addCommand(FakeCommand(
+      command: <String>[
+        ..._kDart2WasmLinuxArgs,
         '--extra-compiler-option=--import-shared-memory',
         '--extra-compiler-option=--shared-memory-max-pages=32768',
-                ],
         '-Ddart.vm.product=true',
-                ...defines.map((String define) => '-D$define'),
-                if (renderer == WebRendererMode.skwasm) ...<String>[
         '-DFLUTTER_WEB_AUTO_DETECT=false',
         '-DFLUTTER_WEB_USE_SKIA=false',
         '-DFLUTTER_WEB_USE_SKWASM=true',
-                ],
-                if (renderer == WebRendererMode.canvaskit) ...<String>[
-                  '-DFLUTTER_WEB_AUTO_DETECT=false',
-                  '-DFLUTTER_WEB_USE_SKIA=true',
-                ],
         '--extra-compiler-option=--depfile=${depFile.absolute.path}',
-                '-O$level',
-                if (strip) '--no-name-section' else '--name-section',
+        '-O2',
+        '--no-name-section',
         '-o',
         environment.buildDir.childFile('main.dart.wasm').absolute.path,
         environment.buildDir.childFile('main.dart').absolute.path,
@@ -939,22 +1062,15 @@ void main() {
       onRun: (_) => outputJsFile..createSync()..writeAsStringSync('foo'))
     );
 
+
     await Dart2WasmTarget(
-              WasmCompilerConfig(
-                optimizationLevel: level,
-                stripWasm: strip,
-                renderer: renderer,
+      const WasmCompilerConfig(
+        renderer: WebRendererMode.skwasm,
       )
     ).build(environment);
-
-            expect(outputJsFile.existsSync(), isTrue);
   }, overrides: <Type, Generator>{
     ProcessManager: () => processManager,
   }));
-        }
-      }
-    }
-  }
 
   test('Generated service worker is empty with none-strategy', () => testbed.run(() {
     final String fileGeneratorsPath =

packages/flutter_tools/test/general.shard/web/compile_web_test.dart

@@ -74,8 +74,7 @@ void main() {
       ServiceWorkerStrategy.offlineFirst,
       compilerConfigs: <WebCompilerConfig>[
         const WasmCompilerConfig(
-          optimizationLevel: 0,
-          stripWasm: false,
+          wasmOpt: WasmOptLevel.none,
           renderer: WebRendererMode.skwasm,
         ),
         const JsCompilerConfig.run(
@@ -104,8 +103,7 @@ void main() {
         label: 'web-compile',
             parameters: CustomDimensions(
               buildEventSettings:
-                  'optimizationLevel: 4; web-renderer: skwasm,canvaskit; web-target: wasm,js;',
-
+                  'RunWasmOpt: none; WasmOmitTypeChecks: false; web-renderer: skwasm,canvaskit; web-target: wasm,js;',
       ),
           ),
         ],
@@ -118,7 +116,7 @@ void main() {
         Event.flutterBuildInfo(
           label: 'web-compile',
           buildType: 'web',
-          settings: 'optimizationLevel: 4; web-renderer: skwasm,canvaskit; web-target: wasm,js;',
+          settings: 'RunWasmOpt: none; WasmOmitTypeChecks: false; web-renderer: skwasm,canvaskit; web-target: wasm,js;',
         ),
       ]),
     );