From 0df58fc2d07107846ec5fb28764283b32e6bd1dc Mon Sep 17 00:00:00 2001
From: Michael Thomsen <mit@google.com>
Date: Tue, 5 Dec 2023 15:44:53 +0000
Subject: [PATCH] Add new `dart compile wasm` command.

Marked as experimental, and only shown when verbose flag is passed:

```
$ dart help compile -v
Compile Dart to various formats.

Usage: dart [vm-options] compile <subcommand> [arguments]
-h, --help    Print this usage information.

Available subcommands:
  aot-snapshot   Compile Dart to an AOT snapshot.
  exe            Compile Dart to a self-contained executable.
  jit-snapshot   Compile Dart to a JIT snapshot.
  js             Compile Dart to JavaScript.
  kernel         Compile Dart to a kernel snapshot.
  wasm           Compile Dart to a WebAssembly/WasmGC module (EXPERIMENTAL).
```

Change-Id: I6a0e65d4fbdd7b2782406b8b9969e14036bf0711
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/304860
Reviewed-by: Ben Konyi <bkonyi@google.com>
Commit-Queue: Michael Thomsen <mit@google.com>
Reviewed-by: Aske Simon Christensen <askesc@google.com>
---
 pkg/dart2wasm/bin/dart2wasm.dart            |   6 +-
 pkg/dart2wasm/lib/compile.dart              |   2 +-
 pkg/dart2wasm/lib/compiler_options.dart     |   8 +-
 pkg/dart2wasm/lib/dart2wasm.dart            |  34 +---
 pkg/dart2wasm/lib/generate_wasm.dart        |  37 ++++
 pkg/dart2wasm/lib/option.dart               |  33 ++--
 pkg/dartdev/lib/src/commands/compile.dart   | 197 ++++++++++++++++++++
 pkg/dartdev/pubspec.yaml                    |   1 +
 pkg/dartdev/test/commands/compile_test.dart | 130 +++++++++----
 pkg/dartdev/test/core_test.dart             |   9 +-
 10 files changed, 371 insertions(+), 86 deletions(-)
 create mode 100644 pkg/dart2wasm/lib/generate_wasm.dart

diff --git a/pkg/dart2wasm/bin/dart2wasm.dart b/pkg/dart2wasm/bin/dart2wasm.dart
index 26b4ce86002..130a13584a8 100644
--- a/pkg/dart2wasm/bin/dart2wasm.dart
+++ b/pkg/dart2wasm/bin/dart2wasm.dart
@@ -2,6 +2,10 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'dart:io';
+
 import 'package:dart2wasm/dart2wasm.dart' as dart2wasm;
 
-Future<int> main(List<String> args) async => await dart2wasm.main(args);
+Future<void> main(List<String> args) async {
+  exitCode = await dart2wasm.main(args);
+}
diff --git a/pkg/dart2wasm/lib/compile.dart b/pkg/dart2wasm/lib/compile.dart
index ea9c6b62b3e..b4581d25147 100644
--- a/pkg/dart2wasm/lib/compile.dart
+++ b/pkg/dart2wasm/lib/compile.dart
@@ -58,7 +58,7 @@ class CompilerOutput {
 /// Returns `null` if an error occurred during compilation. The
 /// [handleDiagnosticMessage] callback will have received an error message
 /// describing the error.
-Future<CompilerOutput?> compileToModule(compiler.CompilerOptions options,
+Future<CompilerOutput?> compileToModule(compiler.WasmCompilerOptions options,
     void Function(DiagnosticMessage) handleDiagnosticMessage) async {
   var succeeded = true;
   void diagnosticMessageHandler(DiagnosticMessage message) {
diff --git a/pkg/dart2wasm/lib/compiler_options.dart b/pkg/dart2wasm/lib/compiler_options.dart
index a3eeb0065a0..f7377f7f25c 100644
--- a/pkg/dart2wasm/lib/compiler_options.dart
+++ b/pkg/dart2wasm/lib/compiler_options.dart
@@ -7,7 +7,7 @@ import 'dart:io';
 import 'package:dart2wasm/translator.dart';
 import 'package:front_end/src/api_unstable/vm.dart' as fe;
 
-class CompilerOptions {
+class WasmCompilerOptions {
   final TranslatorOptions translatorOptions = TranslatorOptions();
 
   Uri sdkPath = Platform.script.resolve("../../../sdk");
@@ -26,10 +26,10 @@ class CompilerOptions {
   String? dumpKernelBeforeTfa;
   String? dumpKernelAfterTfa;
 
-  factory CompilerOptions.defaultOptions() =>
-      CompilerOptions(mainUri: Uri(), outputFile: '');
+  factory WasmCompilerOptions.defaultOptions() =>
+      WasmCompilerOptions(mainUri: Uri(), outputFile: '');
 
-  CompilerOptions({required this.mainUri, required this.outputFile});
+  WasmCompilerOptions({required this.mainUri, required this.outputFile});
 
   void validate() {
     if (translatorOptions.importSharedMemory &&
diff --git a/pkg/dart2wasm/lib/dart2wasm.dart b/pkg/dart2wasm/lib/dart2wasm.dart
index 33a09903934..9bf0553eb3b 100644
--- a/pkg/dart2wasm/lib/dart2wasm.dart
+++ b/pkg/dart2wasm/lib/dart2wasm.dart
@@ -5,16 +5,16 @@
 import 'dart:io';
 
 import 'package:args/args.dart' as args;
-import 'package:front_end/src/api_unstable/vm.dart'
-    show printDiagnosticMessage, resolveInputUri;
+import 'package:front_end/src/api_unstable/vm.dart' show resolveInputUri;
 import 'package:front_end/src/api_unstable/vm.dart' as fe;
 
-import 'package:dart2wasm/compile.dart';
-import 'package:dart2wasm/compiler_options.dart';
+import 'package:dart2wasm/generate_wasm.dart';
 import 'package:dart2wasm/option.dart';
 
 // Used to allow us to keep defaults on their respective option structs.
-final CompilerOptions _d = CompilerOptions.defaultOptions();
+// Note: When adding new options, consider if CLI options should be add
+// to `pkg/dartdev/lib/src/commands/compile.dart` too.
+final WasmCompilerOptions _d = WasmCompilerOptions.defaultOptions();
 
 final List<Option> options = [
   Flag("help", (o, _) {}, abbr: "h", negatable: false, defaultsTo: false),
@@ -96,7 +96,7 @@ Map<String, String> processEnvironment(List<String> defines) =>
       return MapEntry<String, String>(keyAndValue[0], keyAndValue[1]);
     }));
 
-CompilerOptions parseArguments(List<String> arguments) {
+WasmCompilerOptions parseArguments(List<String> arguments) {
   args.ArgParser parser = args.ArgParser();
   for (Option arg in options) {
     arg.applyToParser(parser);
@@ -124,8 +124,8 @@ CompilerOptions parseArguments(List<String> arguments) {
     if (rest.length != 2) {
       throw ArgumentError('Requires two positional file arguments');
     }
-    CompilerOptions compilerOptions =
-        CompilerOptions(mainUri: resolveInputUri(rest[0]), outputFile: rest[1]);
+    WasmCompilerOptions compilerOptions = WasmCompilerOptions(
+        mainUri: resolveInputUri(rest[0]), outputFile: rest[1]);
     for (Option arg in options) {
       if (results.wasParsed(arg.name)) {
         arg.applyToOptions(compilerOptions, results[arg.name]);
@@ -140,20 +140,6 @@ CompilerOptions parseArguments(List<String> arguments) {
 }
 
 Future<int> main(List<String> args) async {
-  CompilerOptions options = parseArguments(args);
-  CompilerOutput? output = await compileToModule(
-      options, (message) => printDiagnosticMessage(message, print));
-
-  if (output == null) {
-    exitCode = 1;
-    return exitCode;
-  }
-
-  await File(options.outputFile).writeAsBytes(output.wasmModule);
-
-  final String outputJSRuntimeFile = options.outputJSRuntimeFile ??
-      '${options.outputFile.substring(0, options.outputFile.lastIndexOf('.'))}.mjs';
-  await File(outputJSRuntimeFile).writeAsString(output.jsRuntime);
-
-  return 0;
+  WasmCompilerOptions options = parseArguments(args);
+  return generateWasm(options);
 }
diff --git a/pkg/dart2wasm/lib/generate_wasm.dart b/pkg/dart2wasm/lib/generate_wasm.dart
new file mode 100644
index 00000000000..234967ea095
--- /dev/null
+++ b/pkg/dart2wasm/lib/generate_wasm.dart
@@ -0,0 +1,37 @@
+import 'dart:io';
+import 'package:dart2wasm/compiler_options.dart';
+import 'package:dart2wasm/compile.dart';
+import 'package:front_end/src/api_unstable/vm.dart' show printDiagnosticMessage;
+export 'package:dart2wasm/compiler_options.dart';
+
+typedef PrintError = void Function(String error);
+
+Future<int> generateWasm(WasmCompilerOptions options,
+    {bool verbose = false, PrintError errorPrinter = print}) async {
+  if (verbose) {
+    print('Running dart compile wasm...');
+    print('  - input file name   = ${options.mainUri}');
+    print('  - output file name  = ${options.outputFile}');
+    print('  - sdkPath           = ${options.sdkPath}');
+    print('  - librariesSpecPath = ${options.librariesSpecPath}');
+    print('  - packagesPath file = ${options.packagesPath}');
+    print('  - platformPath file = ${options.platformPath}');
+  }
+
+  CompilerOutput? output = await compileToModule(
+      options, (message) => printDiagnosticMessage(message, errorPrinter));
+
+  if (output == null) {
+    return 1;
+  }
+
+  final File outFile = File(options.outputFile);
+  outFile.parent.createSync(recursive: true);
+  await outFile.writeAsBytes(output.wasmModule);
+
+  final jsFile = options.outputJSRuntimeFile ??
+      '${options.outputFile.substring(0, options.outputFile.lastIndexOf('.'))}.mjs';
+  await File(jsFile).writeAsString(output.jsRuntime);
+
+  return 0;
+}
diff --git a/pkg/dart2wasm/lib/option.dart b/pkg/dart2wasm/lib/option.dart
index 2ddb6ebfe98..696f6866dc0 100644
--- a/pkg/dart2wasm/lib/option.dart
+++ b/pkg/dart2wasm/lib/option.dart
@@ -11,17 +11,17 @@ import 'package:dart2wasm/compiler_options.dart';
 class Option<T> {
   final String name;
   final void Function(ArgParser a) applyToParser;
-  final void Function(CompilerOptions o, T v) _applyToOptions;
+  final void Function(WasmCompilerOptions o, T v) _applyToOptions;
   final T Function(dynamic v) converter;
 
-  void applyToOptions(CompilerOptions o, dynamic v) =>
+  void applyToOptions(WasmCompilerOptions o, dynamic v) =>
       _applyToOptions(o, converter(v));
 
   Option(this.name, this.applyToParser, this._applyToOptions, this.converter);
 }
 
 class Flag extends Option<bool> {
-  Flag(String name, void applyToOptions(CompilerOptions o, bool v),
+  Flag(String name, void applyToOptions(WasmCompilerOptions o, bool v),
       {String? abbr,
       String? help,
       bool? defaultsTo = false,
@@ -38,31 +38,28 @@ class Flag extends Option<bool> {
 }
 
 class ValueOption<T> extends Option<T> {
-  ValueOption(String name, void applyToOptions(CompilerOptions o, T v),
+  ValueOption(String name, void applyToOptions(WasmCompilerOptions o, T v),
       T converter(dynamic v), {String? defaultsTo, bool hide = false})
-      : super(
-            name,
-            (a) => a.addOption(name, defaultsTo: defaultsTo, hide: hide),
-            applyToOptions,
-            converter);
+      : super(name, (a) => a.addOption(name, defaultsTo: defaultsTo),
+            applyToOptions, converter);
 }
 
 class IntOption extends ValueOption<int> {
-  IntOption(String name, void applyToOptions(CompilerOptions o, int v),
+  IntOption(String name, void applyToOptions(WasmCompilerOptions o, int v),
       {String? defaultsTo})
       : super(name, applyToOptions, (v) => int.parse(v),
             defaultsTo: defaultsTo);
 }
 
 class StringOption extends ValueOption<String> {
-  StringOption(String name, void applyToOptions(CompilerOptions o, String v),
+  StringOption(
+      String name, void applyToOptions(WasmCompilerOptions o, String v),
       {String? defaultsTo, bool hide = false})
-      : super(name, applyToOptions, (v) => v,
-            defaultsTo: defaultsTo, hide: hide);
+      : super(name, applyToOptions, (v) => v, defaultsTo: defaultsTo);
 }
 
 class UriOption extends ValueOption<Uri> {
-  UriOption(String name, void applyToOptions(CompilerOptions o, Uri v),
+  UriOption(String name, void applyToOptions(WasmCompilerOptions o, Uri v),
       {String? defaultsTo})
       : super(name, applyToOptions, (v) => Uri.file(Directory(v).absolute.path),
             defaultsTo: defaultsTo);
@@ -71,7 +68,7 @@ class UriOption extends ValueOption<Uri> {
 class MultiValueOption<T> extends Option<List<T>> {
   MultiValueOption(
       String name,
-      void Function(CompilerOptions o, List<T> v) applyToOptions,
+      void Function(WasmCompilerOptions o, List<T> v) applyToOptions,
       T converter(dynamic v),
       {Iterable<String>? defaultsTo,
       String? abbr})
@@ -83,7 +80,7 @@ class MultiValueOption<T> extends Option<List<T>> {
 }
 
 class IntMultiOption extends MultiValueOption<int> {
-  IntMultiOption(name, void applyToOptions(CompilerOptions o, List<int> v),
+  IntMultiOption(name, void applyToOptions(WasmCompilerOptions o, List<int> v),
       {Iterable<String>? defaultsTo})
       : super(name, applyToOptions, (v) => int.parse(v),
             defaultsTo: defaultsTo);
@@ -91,14 +88,14 @@ class IntMultiOption extends MultiValueOption<int> {
 
 class StringMultiOption extends MultiValueOption<String> {
   StringMultiOption(
-      name, void applyToOptions(CompilerOptions o, List<String> v),
+      name, void applyToOptions(WasmCompilerOptions o, List<String> v),
       {String? abbr, Iterable<String>? defaultsTo})
       : super(name, applyToOptions, (v) => v,
             abbr: abbr, defaultsTo: defaultsTo);
 }
 
 class UriMultiOption extends MultiValueOption<Uri> {
-  UriMultiOption(name, void applyToOptions(CompilerOptions o, List<Uri> v),
+  UriMultiOption(name, void applyToOptions(WasmCompilerOptions o, List<Uri> v),
       {Iterable<String>? defaultsTo})
       : super(name, applyToOptions, (v) => Uri.file(Directory(v).absolute.path),
             defaultsTo: defaultsTo);
diff --git a/pkg/dartdev/lib/src/commands/compile.dart b/pkg/dartdev/lib/src/commands/compile.dart
index 66d1c3d9475..be78c37af85 100644
--- a/pkg/dartdev/lib/src/commands/compile.dart
+++ b/pkg/dartdev/lib/src/commands/compile.dart
@@ -7,8 +7,10 @@ import 'dart:io';
 
 import 'package:args/args.dart';
 import 'package:dart2native/generate.dart';
+import 'package:dart2wasm/generate_wasm.dart';
 import 'package:front_end/src/api_prototype/compiler_options.dart'
     show Verbosity;
+import 'package:front_end/src/api_unstable/vm.dart' as fe;
 import 'package:path/path.dart' as path;
 import 'package:vm/target_os.dart'; // For possible --target-os values.
 
@@ -384,6 +386,200 @@ Remove debugging information from the output and save it separately to the speci
   }
 }
 
+class CompileWasmCommand extends CompileSubcommandCommand {
+  static const String commandName = 'wasm';
+  static const String format = 'wasm';
+  static const String help =
+      'Compile Dart to a WebAssembly/WasmGC module (EXPERIMENTAL).';
+
+  final String optimizer = path.join(binDir.path, 'utils', 'wasm-opt');
+  String optimizerFlags(bool outputNames) =>
+      '-all --closed-world -tnh --type-unfinalizing -O3 --type-ssa'
+      ' --gufa -O3 --type-merging -O1 --type-finalizing'
+      '${outputNames ? ' -g' : ''}';
+  static const String unoptExtension = '.unopt';
+
+  CompileWasmCommand({bool verbose = false})
+      : super(commandName, help, verbose, hidden: !verbose) {
+    argParser
+      ..addOption(
+        outputFileOption.flag,
+        help: outputFileOption.help,
+        abbr: outputFileOption.abbr,
+      )
+      ..addFlag(
+        'optimize',
+        defaultsTo: true,
+        negatable: true,
+        help: 'Optimize wasm output using Binaryen wasm-opt.',
+      )
+      ..addFlag(
+        'omit-type-checks',
+        defaultsTo: false,
+        negatable: false,
+        help: 'Omit runtime type checks, such as covariance and downcasts.',
+        hide: !verbose,
+      )
+      ..addFlag(
+        'name-section',
+        defaultsTo: false,
+        negatable: false,
+        help: 'Include a name section with printable function names.',
+        hide: !verbose,
+      )
+      ..addFlag(
+        'print-wasm',
+        help: 'Print human-readable wasm debug output',
+        hide: !verbose,
+        negatable: false,
+      )
+      ..addFlag(
+        'print-kernel',
+        help: 'Print human-readable Dart kernel debug output',
+        hide: !verbose,
+        negatable: false,
+      )
+      ..addFlag(
+        'verbose',
+        abbr: 'v',
+        help: 'Print debug output during compilation',
+        negatable: false,
+      )
+      ..addFlag(
+        'enable-asserts',
+        help: 'Enable assert statements.',
+        negatable: false,
+      )
+      ..addOption(
+        'shared-memory',
+        help: 'Import a shared memory buffer.'
+            ' The max number of pages must be passed.',
+        valueHelp: 'page count',
+        hide: !verbose,
+      )
+      ..addOption(
+        packagesOption.flag,
+        abbr: packagesOption.abbr,
+        valueHelp: packagesOption.valueHelp,
+        help: packagesOption.help,
+        hide: !verbose,
+      );
+// TODO(): Defines are currently not supported by dart2wasm.
+//      ..addMultiOption(
+//        defineOption.flag,
+//        help: defineOption.help,
+//        abbr: defineOption.abbr,
+//        valueHelp: defineOption.valueHelp,
+//      )
+  }
+
+  @override
+  String get invocation => '${super.invocation} <dart entry point>';
+
+  @override
+  FutureOr<int> run() async {
+    log.stdout('*NOTE*: Compilation to WasmGC is experimental.');
+    log.stdout(
+        'The support may change, or be removed, with no advance notice.\n');
+
+    final libraries = path.absolute(sdk.sdkPath, 'lib', 'libraries.json');
+    if (!Sdk.checkArtifactExists(libraries)) {
+      return 255;
+    }
+    final args = argResults!;
+    bool verbose = this.verbose || args['verbose'];
+    if (args['optimize'] && !Sdk.checkArtifactExists(optimizer)) {
+      return 255;
+    }
+
+    // We expect a single rest argument; the dart entry point.
+    if (args.rest.length != 1) {
+      // This throws.
+      usageException('Missing Dart entry point.');
+    }
+    final String sourcePath = args.rest[0];
+    if (!checkFile(sourcePath)) {
+      return -1;
+    }
+
+    // Determine output file name.
+    String? outputFile = args[outputFileOption.flag];
+    if (outputFile == null) {
+      final inputWithoutDart = sourcePath.endsWith('.dart')
+          ? sourcePath.substring(0, sourcePath.length - 5)
+          : sourcePath;
+      outputFile = '$inputWithoutDart.wasm';
+    }
+
+    final options = WasmCompilerOptions(
+      mainUri: Uri.file(path.absolute(sourcePath)),
+      outputFile: outputFile,
+    );
+    options.librariesSpecPath =
+        Uri.file(path.absolute(sdk.sdkPath, 'lib', 'libraries.json'));
+    options.sdkPath = Uri.file(path.absolute(sdk.sdkPath));
+    options.packagesPath = args[packagesOption.flag];
+    options.translatorOptions.enableAsserts = args['enable-asserts'];
+    options.translatorOptions.printWasm = args['print-wasm'];
+    options.translatorOptions.printKernel = args['print-kernel'];
+    options.translatorOptions.omitTypeChecks = args['omit-type-checks'];
+    options.translatorOptions.nameSection = args['name-section'];
+    if (args['shared-memory'] != null) {
+      int? maxPages = int.tryParse(args['shared-memory']);
+      if (maxPages == null) {
+        usageException(
+            'Error: The --shared-memory flag must specify a number!');
+      }
+      options.translatorOptions.importSharedMemory = true;
+      options.translatorOptions.sharedMemoryMaxPages = maxPages;
+    }
+    // Enable inline classes.
+    // TODO: Remove this when inline classe ship.
+    options.feExperimentalFlags = {fe.ExperimentalFlag.inlineClass: true};
+
+    int result;
+    try {
+      result = await generateWasm(
+        options,
+        verbose: verbose,
+        errorPrinter: (error) => log.stderr(error),
+      );
+      if (result != 0) return compileErrorExitCode;
+    } catch (e, st) {
+      log.stderr('Error: Wasm compilation failed');
+      log.stderr(e.toString());
+      if (verbose) {
+        log.stderr(st.toString());
+      }
+      return compileErrorExitCode;
+    }
+
+    if (args['optimize']) {
+      final unoptFile = outputFile + unoptExtension;
+      final flags = optimizerFlags(args['name-section']);
+      File(outputFile).renameSync(unoptFile);
+      if (verbose) {
+        log.stdout('Optimizing output with: $optimizer $flags');
+      }
+      final processResult = Process.runSync(
+        optimizer,
+        [...flags.split(' '), '-o', outputFile, unoptFile],
+      );
+      if (processResult.exitCode != 0) {
+        log.stderr('Error: Wasm compilation failed while optimizing output');
+        log.stderr(processResult.stderr);
+        return compileErrorExitCode;
+      }
+    }
+
+    final mjsFile =
+        '${options.outputFile.substring(0, options.outputFile.lastIndexOf('.'))}.mjs';
+    log.stdout(
+        "Generated wasm module '$outputFile', and JS init file '$mjsFile'.");
+    return result;
+  }
+}
+
 abstract class CompileSubcommandCommand extends DartdevCommand {
   final outputFileOption = Option(
     flag: 'output',
@@ -487,5 +683,6 @@ class CompileCommand extends DartdevCommand {
       verbose: verbose,
       nativeAssetsExperimentEnabled: nativeAssetsExperimentEnabled,
     ));
+    addSubcommand(CompileWasmCommand(verbose: verbose));
   }
 }
diff --git a/pkg/dartdev/pubspec.yaml b/pkg/dartdev/pubspec.yaml
index be2603a53eb..5e395b186be 100644
--- a/pkg/dartdev/pubspec.yaml
+++ b/pkg/dartdev/pubspec.yaml
@@ -15,6 +15,7 @@ dependencies:
   cli_util: any
   collection: any
   dart2native: any
+  dart2wasm: any
   dart_style: any
   dartdoc: any
   dds: any
diff --git a/pkg/dartdev/test/commands/compile_test.dart b/pkg/dartdev/test/commands/compile_test.dart
index 92c8eea1b82..02359a34596 100644
--- a/pkg/dartdev/test/commands/compile_test.dart
+++ b/pkg/dartdev/test/commands/compile_test.dart
@@ -46,7 +46,7 @@ void defineCompileTests() {
           path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
       final outFile = path.canonicalize(path.join(p.dirPath, 'myexe'));
 
-      var result = await p.run(
+      final result = await p.run(
         [
           'compile',
           'exe',
@@ -172,7 +172,7 @@ void defineCompileTests() {
 
   test('Implicit --help', () async {
     final p = project();
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
       ],
@@ -309,7 +309,7 @@ void defineCompileTests() {
     final p = project(mainSrc: 'void main() { print("I love executables"); }');
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'exe',
@@ -326,7 +326,7 @@ void defineCompileTests() {
     final p = project(mainSrc: 'void main() { print("I love executables"); }');
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'aot-snapshot',
@@ -418,7 +418,7 @@ void defineCompileTests() {
     final outFile = path.canonicalize(path.join(p.dirPath, 'myexe'));
     final targetOS = Platform.isLinux ? 'macos' : 'linux';
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'exe',
@@ -611,7 +611,7 @@ void main() {
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myexe'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'exe',
@@ -641,7 +641,7 @@ void main() {
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myexe'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'exe',
@@ -663,7 +663,7 @@ void main() {
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myexe'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'exe',
@@ -687,7 +687,7 @@ void main() {}
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myexe'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'exe',
@@ -743,7 +743,7 @@ void main() {}
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myexe'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'exe',
@@ -773,7 +773,7 @@ void main() {
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myexe'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'exe',
@@ -791,12 +791,68 @@ void main() {
     expect(result.exitCode, 0);
   }, skip: isRunningOnIA32);
 
+  test('Compile wasm with error', () async {
+    final p = project(mainSrc: '''
+void main() {
+  int? i;
+  i.isEven;
+}
+''');
+    final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
+    final outFile = path.canonicalize(path.join(p.dirPath, 'mywasm'));
+
+    final result = await p.run(
+      [
+        'compile',
+        'wasm',
+        '-o',
+        outFile,
+        inFile,
+      ],
+    );
+
+    expect(result.stdout, contains('Compilation to WasmGC is experimental'));
+    expect(result.stderr, contains('Error: '));
+    // The CFE doesn't print to stderr, so all output is piped to stderr, even
+    // including info-only output:
+    expect(result.stderr, isNot(contains(soundNullSafetyMessage)));
+    expect(result.exitCode, compileErrorExitCode);
+    expect(File(outFile).existsSync(), false,
+        reason: 'File not found: $outFile');
+  }, skip: isRunningOnIA32);
+
+  test('Compile wasm with warnings', () async {
+    final p = project(mainSrc: '''
+void main() {
+  int i = 0;
+  i?.isEven;
+}
+''');
+    final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
+    final outFile = path.canonicalize(path.join(p.dirPath, 'mywasm.wasm'));
+
+    final result = await p.run(
+      [
+        'compile',
+        'wasm',
+        '-o',
+        outFile,
+        inFile,
+      ],
+    );
+
+    expect(result.stderr, contains('Warning: '));
+    expect(result.exitCode, 0);
+    expect(File(outFile).existsSync(), true,
+        reason: 'File not found: $outFile');
+  }, skip: isRunningOnIA32);
+
   test('Compile JS with sound null safety', () async {
     final p = project(mainSrc: '''void main() {}''');
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myjs'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'js',
@@ -821,7 +877,7 @@ void main() {}
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myjs'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'js',
@@ -844,7 +900,7 @@ void main() {}
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myjs'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'js',
@@ -872,7 +928,7 @@ void main() {
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myjs'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'js',
@@ -893,7 +949,7 @@ void main() {
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myaot'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'aot-snapshot',
@@ -917,7 +973,7 @@ void main() {}
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myaot'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'aot-snapshot',
@@ -941,7 +997,7 @@ void main() {}
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myaot'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'aot-snapshot',
@@ -971,7 +1027,7 @@ void main() {
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myaot'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'aot-snapshot',
@@ -999,7 +1055,7 @@ void main() {
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myaot'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'aot-snapshot',
@@ -1022,7 +1078,7 @@ void main() {
     final p = project(mainSrc: '''void main() {}''');
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'kernel',
@@ -1046,7 +1102,7 @@ void main() {
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'mydill'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'kernel',
@@ -1075,7 +1131,7 @@ void main() {
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'mydill'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'kernel',
@@ -1100,7 +1156,7 @@ void main() {}
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'mydill'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'kernel',
@@ -1125,7 +1181,7 @@ void main() {}
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'mydill'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'kernel',
@@ -1149,7 +1205,7 @@ void main() {}
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'mydill'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'kernel',
@@ -1172,7 +1228,7 @@ void main() {}
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'mydill'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'kernel',
@@ -1199,7 +1255,7 @@ void main() {
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'mydill'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'kernel',
@@ -1224,7 +1280,7 @@ void main() {
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'mydill'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'kernel',
@@ -1245,7 +1301,7 @@ void main() {
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myjit'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'jit-snapshot',
@@ -1268,7 +1324,7 @@ void main() {}
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myjit'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'jit-snapshot',
@@ -1291,7 +1347,7 @@ void main() {}
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myjit'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'jit-snapshot',
@@ -1315,7 +1371,7 @@ void main() {}
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'mydill'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'jit-snapshot',
@@ -1338,7 +1394,7 @@ void main() {}
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myjit'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'jit-snapshot',
@@ -1366,7 +1422,7 @@ void main() {}
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myjit'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'jit-snapshot',
@@ -1392,7 +1448,7 @@ void main() {
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myjit'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'jit-snapshot',
@@ -1417,7 +1473,7 @@ void main() {
     final inFile = path.canonicalize(path.join(p.dirPath, p.relativeFilePath));
     final outFile = path.canonicalize(path.join(p.dirPath, 'myjit'));
 
-    var result = await p.run(
+    final result = await p.run(
       [
         'compile',
         'jit-snapshot',
diff --git a/pkg/dartdev/test/core_test.dart b/pkg/dartdev/test/core_test.dart
index d5b28d70da1..5a4549d7c0d 100644
--- a/pkg/dartdev/test/core_test.dart
+++ b/pkg/dartdev/test/core_test.dart
@@ -41,7 +41,7 @@ void _dartdevCommand() {
   });
 
   test('compile', () {
-    assertDartdevCommandProperties(CompileCommand(), 'compile', 'compile', 5);
+    assertDartdevCommandProperties(CompileCommand(), 'compile', 'compile', 6);
   });
 
   test('compile/js', () {
@@ -79,6 +79,13 @@ void _dartdevCommand() {
         'compile/aot-snapshot');
   });
 
+  test('compile/wasm', () {
+    assertDartdevCommandProperties(
+        CompileCommand().subcommands['wasm'] as DartdevCommand,
+        'wasm',
+        'compile/wasm');
+  });
+
   test('create', () {
     assertDartdevCommandProperties(CreateCommand(), 'create', 'create');
   });