packages/flutter_tools/lib/src/build_system/targets/common.dart - external/github.com/flutter/flutter - Git at Google

 // Copyright 2014 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 import 'package:package_config/package_config.dart';

 import '../../artifacts.dart';
 import '../../base/build.dart';
 import '../../base/file_system.dart';
 import '../../build_info.dart';
 import '../../compile.dart';
 import '../../dart/package_map.dart';
 import '../../globals.dart' as globals hide fs, processManager, artifacts, logger;
 import '../build_system.dart';
 import '../depfile.dart';
 import '../exceptions.dart';
 import 'assets.dart';
 import 'icon_tree_shaker.dart';
 import 'localizations.dart';

 /// The define to pass a [BuildMode].
 const String kBuildMode = 'BuildMode';

 /// The define to pass whether we compile 64-bit android-arm code.
 const String kTargetPlatform = 'TargetPlatform';

 /// The define to control what target file is used.
 const String kTargetFile = 'TargetFile';

 /// The define to control whether the AOT snapshot is built with bitcode.
 const String kBitcodeFlag = 'EnableBitcode';

 /// Whether to enable or disable track widget creation.
 const String kTrackWidgetCreation = 'TrackWidgetCreation';

 /// Additional configuration passed to the dart front end.
 ///
 /// This is expected to be a comma separated list of strings.
 const String kExtraFrontEndOptions = 'ExtraFrontEndOptions';

 /// Additional configuration passed to gen_snapshot.
 ///
 /// This is expected to be a comma separated list of strings.
 const String kExtraGenSnapshotOptions = 'ExtraGenSnapshotOptions';

 /// Whether to strip source code information out of release builds and where to save it.
 const String kSplitDebugInfo = 'SplitDebugInfo';

 /// Alternative scheme for file URIs.
 ///
 /// May be used along with [kFileSystemRoots] to support a multi-root
 /// filesystem.
 const String kFileSystemScheme = 'FileSystemScheme';

 /// Additional filesystem roots.
 ///
 /// If provided, must be used along with [kFileSystemScheme].
 const String kFileSystemRoots = 'FileSystemRoots';

 /// The define to control what iOS architectures are built for.
 ///
 /// This is expected to be a comma-separated list of architectures. If not
 /// provided, defaults to arm64.
 ///
 /// The other supported value is armv7, the 32-bit iOS architecture.
 const String kIosArchs = 'IosArchs';

 /// Whether to enable Dart obfuscation and where to save the symbol map.
 const String kDartObfuscation = 'DartObfuscation';

 /// An output directory where one or more code-size measurements may be written.
 const String kCodeSizeDirectory = 'CodeSizeDirectory';

 /// Copies the pre-built flutter bundle.
 // This is a one-off rule for implementing build bundle in terms of assemble.
 class CopyFlutterBundle extends Target {
   const CopyFlutterBundle();

   @override
   String get name => 'copy_flutter_bundle';

   @override
   List<Source> get inputs => const <Source>[
     Source.artifact(Artifact.vmSnapshotData, mode: BuildMode.debug),
     Source.artifact(Artifact.isolateSnapshotData, mode: BuildMode.debug),
     Source.pattern('{BUILD_DIR}/app.dill'),
     ...IconTreeShaker.inputs,
   ];

   @override
   List<Source> get outputs => const <Source>[
     Source.pattern('{OUTPUT_DIR}/vm_snapshot_data'),
     Source.pattern('{OUTPUT_DIR}/isolate_snapshot_data'),
     Source.pattern('{OUTPUT_DIR}/kernel_blob.bin'),
   ];

   @override
   List<String> get depfiles => <String>[
     'flutter_assets.d'
   ];

   @override
   Future<void> build(Environment environment) async {
     if (environment.defines[kBuildMode] == null) {
       throw MissingDefineException(kBuildMode, 'copy_flutter_bundle');
     }
     final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
     environment.outputDir.createSync(recursive: true);

     // Only copy the prebuilt runtimes and kernel blob in debug mode.
     if (buildMode == BuildMode.debug) {
       final String vmSnapshotData = environment.artifacts.getArtifactPath(Artifact.vmSnapshotData, mode: BuildMode.debug);
       final String isolateSnapshotData = environment.artifacts.getArtifactPath(Artifact.isolateSnapshotData, mode: BuildMode.debug);
       environment.buildDir.childFile('app.dill')
           .copySync(environment.outputDir.childFile('kernel_blob.bin').path);
       environment.fileSystem.file(vmSnapshotData)
           .copySync(environment.outputDir.childFile('vm_snapshot_data').path);
       environment.fileSystem.file(isolateSnapshotData)
           .copySync(environment.outputDir.childFile('isolate_snapshot_data').path);
     }
     final Depfile assetDepfile = await copyAssets(
       environment,
       environment.outputDir,
       targetPlatform: TargetPlatform.android,
     );
     final DepfileService depfileService = DepfileService(
       fileSystem: environment.fileSystem,
       logger: environment.logger,
     );
     depfileService.writeToFile(
       assetDepfile,
       environment.buildDir.childFile('flutter_assets.d'),
     );
   }

   @override
   List<Target> get dependencies => const <Target>[
     KernelSnapshot(),
   ];
 }

 /// Copies the pre-built flutter bundle for release mode.
 class ReleaseCopyFlutterBundle extends CopyFlutterBundle {
   const ReleaseCopyFlutterBundle();

   @override
   String get name => 'release_flutter_bundle';

   @override
   List<Source> get inputs => const <Source>[];

   @override
   List<Source> get outputs => const <Source>[];

   @override
   List<String> get depfiles => const <String>[
     'flutter_assets.d',
   ];

   @override
   List<Target> get dependencies => const <Target>[];
 }

 /// Generate a snapshot of the dart code used in the program.
 ///
 /// Note that this target depends on the `.dart_tool/package_config.json` file
 /// even though it is not listed as an input. Pub inserts a timestamp into
 /// the file which causes unnecessary rebuilds, so instead a subset of the contents
 /// are used an input instead.
 class KernelSnapshot extends Target {
   const KernelSnapshot();

   @override
   String get name => 'kernel_snapshot';

   @override
   List<Source> get inputs => const <Source>[
     Source.pattern('{PROJECT_DIR}/.dart_tool/package_config_subset'),
     Source.pattern('{FLUTTER_ROOT}/packages/flutter_tools/lib/src/build_system/targets/common.dart'),
     Source.artifact(Artifact.platformKernelDill),
     Source.artifact(Artifact.engineDartBinary),
     Source.artifact(Artifact.frontendServerSnapshotForEngineDartSdk),
   ];

   @override
   List<Source> get outputs => const <Source>[];

   @override
   List<String> get depfiles => <String>[
     'kernel_snapshot.d',
   ];

   @override
   List<Target> get dependencies => const <Target>[
     GenerateLocalizationsTarget(),
   ];

   @override
   Future<void> build(Environment environment) async {
     final KernelCompiler compiler = KernelCompiler(
       fileSystem: environment.fileSystem,
       logger: environment.logger,
       processManager: environment.processManager,
       artifacts: environment.artifacts,
       fileSystemRoots: <String>[],
       fileSystemScheme: null,
     );
     if (environment.defines[kBuildMode] == null) {
       throw MissingDefineException(kBuildMode, 'kernel_snapshot');
     }
     if (environment.defines[kTargetPlatform] == null) {
       throw MissingDefineException(kTargetPlatform, 'kernel_snapshot');
     }
     final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
     final String targetFile = environment.defines[kTargetFile] ?? environment.fileSystem.path.join('lib', 'main.dart');
     final File packagesFile = environment.projectDir
       .childDirectory('.dart_tool')
       .childFile('package_config.json');
     final String targetFileAbsolute = environment.fileSystem.file(targetFile).absolute.path;
     // everything besides 'false' is considered to be enabled.
     final bool trackWidgetCreation = environment.defines[kTrackWidgetCreation] != 'false';
     final TargetPlatform targetPlatform = getTargetPlatformForName(environment.defines[kTargetPlatform]);

     // This configuration is all optional.
     final List<String> extraFrontEndOptions = decodeDartDefines(environment.defines, kExtraFrontEndOptions);
     final List<String> fileSystemRoots = environment.defines[kFileSystemRoots]?.split(',');
     final String fileSystemScheme = environment.defines[kFileSystemScheme];

     TargetModel targetModel = TargetModel.flutter;
     if (targetPlatform == TargetPlatform.fuchsia_x64 ||
         targetPlatform == TargetPlatform.fuchsia_arm64) {
       targetModel = TargetModel.flutterRunner;
     }
     // Force linking of the platform for desktop embedder targets since these
     // do not correctly load the core snapshots in debug mode.
     // See https://github.com/flutter/flutter/issues/44724
     bool forceLinkPlatform;
     switch (targetPlatform) {
       case TargetPlatform.darwin_x64:
       case TargetPlatform.windows_x64:
       case TargetPlatform.linux_x64:
         forceLinkPlatform = true;
         break;
       default:
         forceLinkPlatform = false;
     }

     final PackageConfig packageConfig = await loadPackageConfigWithLogging(
       packagesFile,
       logger: environment.logger,
     );

     final CompilerOutput output = await compiler.compile(
       sdkRoot: environment.artifacts.getArtifactPath(
         Artifact.flutterPatchedSdkPath,
         platform: targetPlatform,
         mode: buildMode,
       ),
       aot: buildMode.isPrecompiled,
       buildMode: buildMode,
       trackWidgetCreation: trackWidgetCreation && buildMode == BuildMode.debug,
       targetModel: targetModel,
       outputFilePath: environment.buildDir.childFile('app.dill').path,
       packagesPath: packagesFile.path,
       linkPlatformKernelIn: forceLinkPlatform || buildMode.isPrecompiled,
       mainPath: targetFileAbsolute,
       depFilePath: environment.buildDir.childFile('kernel_snapshot.d').path,
       extraFrontEndOptions: extraFrontEndOptions,
       fileSystemRoots: fileSystemRoots,
       fileSystemScheme: fileSystemScheme,
       dartDefines: decodeDartDefines(environment.defines, kDartDefines),
       packageConfig: packageConfig,
     );
     if (output == null || output.errorCount != 0) {
       throw Exception();
     }
   }
 }

 /// Supports compiling a dart kernel file to an ELF binary.
 abstract class AotElfBase extends Target {
   const AotElfBase();

   @override
   String get analyticsName => 'android_aot';

   @override
   Future<void> build(Environment environment) async {
     final AOTSnapshotter snapshotter = AOTSnapshotter(
       reportTimings: false,
       fileSystem: environment.fileSystem,
       logger: environment.logger,
       xcode: globals.xcode,
       processManager: environment.processManager,
       artifacts: environment.artifacts,
     );
     final String outputPath = environment.buildDir.path;
     if (environment.defines[kBuildMode] == null) {
       throw MissingDefineException(kBuildMode, 'aot_elf');
     }
     if (environment.defines[kTargetPlatform] == null) {
       throw MissingDefineException(kTargetPlatform, 'aot_elf');
     }
     final List<String> extraGenSnapshotOptions = decodeDartDefines(environment.defines, kExtraGenSnapshotOptions);
     final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
     final TargetPlatform targetPlatform = getTargetPlatformForName(environment.defines[kTargetPlatform]);
     final String splitDebugInfo = environment.defines[kSplitDebugInfo];
     final bool dartObfuscation = environment.defines[kDartObfuscation] == 'true';
     final String codeSizeDirectory = environment.defines[kCodeSizeDirectory];

     if (codeSizeDirectory != null) {
       final File codeSizeFile = environment.fileSystem
         .directory(codeSizeDirectory)
         .childFile('snapshot.${environment.defines[kTargetPlatform]}.json');
       final File precompilerTraceFile = environment.fileSystem
         .directory(codeSizeDirectory)
         .childFile('trace.${environment.defines[kTargetPlatform]}.json');
       extraGenSnapshotOptions.add('--write-v8-snapshot-profile-to=${codeSizeFile.path}');
       extraGenSnapshotOptions.add('--trace-precompiler-to=${precompilerTraceFile.path}');
     }

     final int snapshotExitCode = await snapshotter.build(
       platform: targetPlatform,
       buildMode: buildMode,
       mainPath: environment.buildDir.childFile('app.dill').path,
       packagesPath: environment.projectDir.childFile('.packages').path,
       outputPath: outputPath,
       bitcode: false,
       extraGenSnapshotOptions: extraGenSnapshotOptions,
       splitDebugInfo: splitDebugInfo,
       dartObfuscation: dartObfuscation,
     );
     if (snapshotExitCode != 0) {
       throw Exception('AOT snapshotter exited with code $snapshotExitCode');
     }
   }
 }

 /// Generate an ELF binary from a dart kernel file in profile mode.
 class AotElfProfile extends AotElfBase {
   const AotElfProfile(this.targetPlatform);

   @override
   String get name => 'aot_elf_profile';

   @override
   List<Source> get inputs => <Source>[
     const Source.pattern('{FLUTTER_ROOT}/packages/flutter_tools/lib/src/build_system/targets/common.dart'),
     const Source.pattern('{BUILD_DIR}/app.dill'),
     const Source.artifact(Artifact.engineDartBinary),
     const Source.artifact(Artifact.skyEnginePath),
     Source.artifact(Artifact.genSnapshot,
       platform: targetPlatform,
       mode: BuildMode.profile,
     ),
   ];

   @override
   List<Source> get outputs => const <Source>[
     Source.pattern('{BUILD_DIR}/app.so'),
   ];

   @override
   List<Target> get dependencies => const <Target>[
     KernelSnapshot(),
   ];

   final TargetPlatform targetPlatform;
 }

 /// Generate an ELF binary from a dart kernel file in release mode.
 class AotElfRelease extends AotElfBase {
   const AotElfRelease(this.targetPlatform);

   @override
   String get name => 'aot_elf_release';

   @override
   List<Source> get inputs => <Source>[
     const Source.pattern('{FLUTTER_ROOT}/packages/flutter_tools/lib/src/build_system/targets/common.dart'),
     const Source.pattern('{BUILD_DIR}/app.dill'),
     const Source.artifact(Artifact.engineDartBinary),
     const Source.artifact(Artifact.skyEnginePath),
     Source.artifact(Artifact.genSnapshot,
       platform: targetPlatform,
       mode: BuildMode.release,
     ),
   ];

   @override
   List<Source> get outputs => const <Source>[
     Source.pattern('{BUILD_DIR}/app.so'),
   ];

   @override
   List<Target> get dependencies => const <Target>[
     KernelSnapshot(),
   ];

   final TargetPlatform targetPlatform;
 }

 /// Copies the pre-built flutter aot bundle.
 // This is a one-off rule for implementing build aot in terms of assemble.
 abstract class CopyFlutterAotBundle extends Target {
   const CopyFlutterAotBundle();

   @override
   List<Source> get inputs => const <Source>[
     Source.pattern('{BUILD_DIR}/app.so'),
   ];

   @override
   List<Source> get outputs => const <Source>[
     Source.pattern('{OUTPUT_DIR}/app.so'),
   ];

   @override
   Future<void> build(Environment environment) async {
     final File outputFile = environment.outputDir.childFile('app.so');
     if (!outputFile.parent.existsSync()) {
       outputFile.parent.createSync(recursive: true);
     }
     environment.buildDir.childFile('app.so').copySync(outputFile.path);
   }
 }
	// Copyright 2014 The Flutter Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	import 'package:package_config/package_config.dart';

	import '../../artifacts.dart';
	import '../../base/build.dart';
	import '../../base/file_system.dart';
	import '../../build_info.dart';
	import '../../compile.dart';
	import '../../dart/package_map.dart';
	import '../../globals.dart' as globals hide fs, processManager, artifacts, logger;
	import '../build_system.dart';
	import '../depfile.dart';
	import '../exceptions.dart';
	import 'assets.dart';
	import 'icon_tree_shaker.dart';
	import 'localizations.dart';

	/// The define to pass a [BuildMode].
	const String kBuildMode = 'BuildMode';

	/// The define to pass whether we compile 64-bit android-arm code.
	const String kTargetPlatform = 'TargetPlatform';

	/// The define to control what target file is used.
	const String kTargetFile = 'TargetFile';

	/// The define to control whether the AOT snapshot is built with bitcode.
	const String kBitcodeFlag = 'EnableBitcode';

	/// Whether to enable or disable track widget creation.
	const String kTrackWidgetCreation = 'TrackWidgetCreation';

	/// Additional configuration passed to the dart front end.
	///
	/// This is expected to be a comma separated list of strings.
	const String kExtraFrontEndOptions = 'ExtraFrontEndOptions';

	/// Additional configuration passed to gen_snapshot.
	///
	/// This is expected to be a comma separated list of strings.
	const String kExtraGenSnapshotOptions = 'ExtraGenSnapshotOptions';

	/// Whether to strip source code information out of release builds and where to save it.
	const String kSplitDebugInfo = 'SplitDebugInfo';

	/// Alternative scheme for file URIs.
	///
	/// May be used along with [kFileSystemRoots] to support a multi-root
	/// filesystem.
	const String kFileSystemScheme = 'FileSystemScheme';

	/// Additional filesystem roots.
	///
	/// If provided, must be used along with [kFileSystemScheme].
	const String kFileSystemRoots = 'FileSystemRoots';

	/// The define to control what iOS architectures are built for.
	///
	/// This is expected to be a comma-separated list of architectures. If not
	/// provided, defaults to arm64.
	///
	/// The other supported value is armv7, the 32-bit iOS architecture.
	const String kIosArchs = 'IosArchs';

	/// Whether to enable Dart obfuscation and where to save the symbol map.
	const String kDartObfuscation = 'DartObfuscation';

	/// An output directory where one or more code-size measurements may be written.
	const String kCodeSizeDirectory = 'CodeSizeDirectory';

	/// Copies the pre-built flutter bundle.
	// This is a one-off rule for implementing build bundle in terms of assemble.
	class CopyFlutterBundle extends Target {
	const CopyFlutterBundle();

	@override
	String get name => 'copy_flutter_bundle';

	@override
	List<Source> get inputs => const <Source>[
	Source.artifact(Artifact.vmSnapshotData, mode: BuildMode.debug),
	Source.artifact(Artifact.isolateSnapshotData, mode: BuildMode.debug),
	Source.pattern('{BUILD_DIR}/app.dill'),
	...IconTreeShaker.inputs,
	];

	@override
	List<Source> get outputs => const <Source>[
	Source.pattern('{OUTPUT_DIR}/vm_snapshot_data'),
	Source.pattern('{OUTPUT_DIR}/isolate_snapshot_data'),
	Source.pattern('{OUTPUT_DIR}/kernel_blob.bin'),
	];

	@override
	List<String> get depfiles => <String>[
	'flutter_assets.d'
	];

	@override
	Future<void> build(Environment environment) async {
	if (environment.defines[kBuildMode] == null) {
	throw MissingDefineException(kBuildMode, 'copy_flutter_bundle');
	}
	final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
	environment.outputDir.createSync(recursive: true);

	// Only copy the prebuilt runtimes and kernel blob in debug mode.
	if (buildMode == BuildMode.debug) {
	final String vmSnapshotData = environment.artifacts.getArtifactPath(Artifact.vmSnapshotData, mode: BuildMode.debug);
	final String isolateSnapshotData = environment.artifacts.getArtifactPath(Artifact.isolateSnapshotData, mode: BuildMode.debug);
	environment.buildDir.childFile('app.dill')
	.copySync(environment.outputDir.childFile('kernel_blob.bin').path);
	environment.fileSystem.file(vmSnapshotData)
	.copySync(environment.outputDir.childFile('vm_snapshot_data').path);
	environment.fileSystem.file(isolateSnapshotData)
	.copySync(environment.outputDir.childFile('isolate_snapshot_data').path);
	}
	final Depfile assetDepfile = await copyAssets(
	environment,
	environment.outputDir,
	targetPlatform: TargetPlatform.android,
	);
	final DepfileService depfileService = DepfileService(
	fileSystem: environment.fileSystem,
	logger: environment.logger,
	);
	depfileService.writeToFile(
	assetDepfile,
	environment.buildDir.childFile('flutter_assets.d'),
	);
	}

	@override
	List<Target> get dependencies => const <Target>[
	KernelSnapshot(),
	];
	}

	/// Copies the pre-built flutter bundle for release mode.
	class ReleaseCopyFlutterBundle extends CopyFlutterBundle {
	const ReleaseCopyFlutterBundle();

	@override
	String get name => 'release_flutter_bundle';

	@override
	List<Source> get inputs => const <Source>[];

	@override
	List<Source> get outputs => const <Source>[];

	@override
	List<String> get depfiles => const <String>[
	'flutter_assets.d',
	];

	@override
	List<Target> get dependencies => const <Target>[];
	}

	/// Generate a snapshot of the dart code used in the program.
	///
	/// Note that this target depends on the `.dart_tool/package_config.json` file
	/// even though it is not listed as an input. Pub inserts a timestamp into
	/// the file which causes unnecessary rebuilds, so instead a subset of the contents
	/// are used an input instead.
	class KernelSnapshot extends Target {
	const KernelSnapshot();

	@override
	String get name => 'kernel_snapshot';

	@override
	List<Source> get inputs => const <Source>[
	Source.pattern('{PROJECT_DIR}/.dart_tool/package_config_subset'),
	Source.pattern('{FLUTTER_ROOT}/packages/flutter_tools/lib/src/build_system/targets/common.dart'),
	Source.artifact(Artifact.platformKernelDill),
	Source.artifact(Artifact.engineDartBinary),
	Source.artifact(Artifact.frontendServerSnapshotForEngineDartSdk),
	];

	@override
	List<Source> get outputs => const <Source>[];

	@override
	List<String> get depfiles => <String>[
	'kernel_snapshot.d',
	];

	@override
	List<Target> get dependencies => const <Target>[
	GenerateLocalizationsTarget(),
	];

	@override
	Future<void> build(Environment environment) async {
	final KernelCompiler compiler = KernelCompiler(
	fileSystem: environment.fileSystem,
	logger: environment.logger,
	processManager: environment.processManager,
	artifacts: environment.artifacts,
	fileSystemRoots: <String>[],
	fileSystemScheme: null,
	);
	if (environment.defines[kBuildMode] == null) {
	throw MissingDefineException(kBuildMode, 'kernel_snapshot');
	}
	if (environment.defines[kTargetPlatform] == null) {
	throw MissingDefineException(kTargetPlatform, 'kernel_snapshot');
	}
	final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
	final String targetFile = environment.defines[kTargetFile] ?? environment.fileSystem.path.join('lib', 'main.dart');
	final File packagesFile = environment.projectDir
	.childDirectory('.dart_tool')
	.childFile('package_config.json');
	final String targetFileAbsolute = environment.fileSystem.file(targetFile).absolute.path;
	// everything besides 'false' is considered to be enabled.
	final bool trackWidgetCreation = environment.defines[kTrackWidgetCreation] != 'false';
	final TargetPlatform targetPlatform = getTargetPlatformForName(environment.defines[kTargetPlatform]);

	// This configuration is all optional.
	final List<String> extraFrontEndOptions = decodeDartDefines(environment.defines, kExtraFrontEndOptions);
	final List<String> fileSystemRoots = environment.defines[kFileSystemRoots]?.split(',');
	final String fileSystemScheme = environment.defines[kFileSystemScheme];

	TargetModel targetModel = TargetModel.flutter;
	if (targetPlatform == TargetPlatform.fuchsia_x64 \|\|
	targetPlatform == TargetPlatform.fuchsia_arm64) {
	targetModel = TargetModel.flutterRunner;
	}
	// Force linking of the platform for desktop embedder targets since these
	// do not correctly load the core snapshots in debug mode.
	// See https://github.com/flutter/flutter/issues/44724
	bool forceLinkPlatform;
	switch (targetPlatform) {
	case TargetPlatform.darwin_x64:
	case TargetPlatform.windows_x64:
	case TargetPlatform.linux_x64:
	forceLinkPlatform = true;
	break;
	default:
	forceLinkPlatform = false;
	}

	final PackageConfig packageConfig = await loadPackageConfigWithLogging(
	packagesFile,
	logger: environment.logger,
	);

	final CompilerOutput output = await compiler.compile(
	sdkRoot: environment.artifacts.getArtifactPath(
	Artifact.flutterPatchedSdkPath,
	platform: targetPlatform,
	mode: buildMode,
	),
	aot: buildMode.isPrecompiled,
	buildMode: buildMode,
	trackWidgetCreation: trackWidgetCreation && buildMode == BuildMode.debug,
	targetModel: targetModel,
	outputFilePath: environment.buildDir.childFile('app.dill').path,
	packagesPath: packagesFile.path,
	linkPlatformKernelIn: forceLinkPlatform \|\| buildMode.isPrecompiled,
	mainPath: targetFileAbsolute,
	depFilePath: environment.buildDir.childFile('kernel_snapshot.d').path,
	extraFrontEndOptions: extraFrontEndOptions,
	fileSystemRoots: fileSystemRoots,
	fileSystemScheme: fileSystemScheme,
	dartDefines: decodeDartDefines(environment.defines, kDartDefines),
	packageConfig: packageConfig,
	);
	if (output == null \|\| output.errorCount != 0) {
	throw Exception();
	}
	}
	}

	/// Supports compiling a dart kernel file to an ELF binary.
	abstract class AotElfBase extends Target {
	const AotElfBase();

	@override
	String get analyticsName => 'android_aot';

	@override
	Future<void> build(Environment environment) async {
	final AOTSnapshotter snapshotter = AOTSnapshotter(
	reportTimings: false,
	fileSystem: environment.fileSystem,
	logger: environment.logger,
	xcode: globals.xcode,
	processManager: environment.processManager,
	artifacts: environment.artifacts,
	);
	final String outputPath = environment.buildDir.path;
	if (environment.defines[kBuildMode] == null) {
	throw MissingDefineException(kBuildMode, 'aot_elf');
	}
	if (environment.defines[kTargetPlatform] == null) {
	throw MissingDefineException(kTargetPlatform, 'aot_elf');
	}
	final List<String> extraGenSnapshotOptions = decodeDartDefines(environment.defines, kExtraGenSnapshotOptions);
	final BuildMode buildMode = getBuildModeForName(environment.defines[kBuildMode]);
	final TargetPlatform targetPlatform = getTargetPlatformForName(environment.defines[kTargetPlatform]);
	final String splitDebugInfo = environment.defines[kSplitDebugInfo];
	final bool dartObfuscation = environment.defines[kDartObfuscation] == 'true';
	final String codeSizeDirectory = environment.defines[kCodeSizeDirectory];

	if (codeSizeDirectory != null) {
	final File codeSizeFile = environment.fileSystem
	.directory(codeSizeDirectory)
	.childFile('snapshot.${environment.defines[kTargetPlatform]}.json');
	final File precompilerTraceFile = environment.fileSystem
	.directory(codeSizeDirectory)
	.childFile('trace.${environment.defines[kTargetPlatform]}.json');
	extraGenSnapshotOptions.add('--write-v8-snapshot-profile-to=${codeSizeFile.path}');
	extraGenSnapshotOptions.add('--trace-precompiler-to=${precompilerTraceFile.path}');
	}

	final int snapshotExitCode = await snapshotter.build(
	platform: targetPlatform,
	buildMode: buildMode,
	mainPath: environment.buildDir.childFile('app.dill').path,
	packagesPath: environment.projectDir.childFile('.packages').path,
	outputPath: outputPath,
	bitcode: false,
	extraGenSnapshotOptions: extraGenSnapshotOptions,
	splitDebugInfo: splitDebugInfo,
	dartObfuscation: dartObfuscation,
	);
	if (snapshotExitCode != 0) {
	throw Exception('AOT snapshotter exited with code $snapshotExitCode');
	}
	}
	}

	/// Generate an ELF binary from a dart kernel file in profile mode.
	class AotElfProfile extends AotElfBase {
	const AotElfProfile(this.targetPlatform);

	@override
	String get name => 'aot_elf_profile';

	@override
	List<Source> get inputs => <Source>[
	const Source.pattern('{FLUTTER_ROOT}/packages/flutter_tools/lib/src/build_system/targets/common.dart'),
	const Source.pattern('{BUILD_DIR}/app.dill'),
	const Source.artifact(Artifact.engineDartBinary),
	const Source.artifact(Artifact.skyEnginePath),
	Source.artifact(Artifact.genSnapshot,
	platform: targetPlatform,
	mode: BuildMode.profile,
	),
	];

	@override
	List<Source> get outputs => const <Source>[
	Source.pattern('{BUILD_DIR}/app.so'),
	];

	@override
	List<Target> get dependencies => const <Target>[
	KernelSnapshot(),
	];

	final TargetPlatform targetPlatform;
	}

	/// Generate an ELF binary from a dart kernel file in release mode.
	class AotElfRelease extends AotElfBase {
	const AotElfRelease(this.targetPlatform);

	@override
	String get name => 'aot_elf_release';

	@override
	List<Source> get inputs => <Source>[
	const Source.pattern('{FLUTTER_ROOT}/packages/flutter_tools/lib/src/build_system/targets/common.dart'),
	const Source.pattern('{BUILD_DIR}/app.dill'),
	const Source.artifact(Artifact.engineDartBinary),
	const Source.artifact(Artifact.skyEnginePath),
	Source.artifact(Artifact.genSnapshot,
	platform: targetPlatform,
	mode: BuildMode.release,
	),
	];

	@override
	List<Source> get outputs => const <Source>[
	Source.pattern('{BUILD_DIR}/app.so'),
	];

	@override
	List<Target> get dependencies => const <Target>[
	KernelSnapshot(),
	];

	final TargetPlatform targetPlatform;
	}

	/// Copies the pre-built flutter aot bundle.
	// This is a one-off rule for implementing build aot in terms of assemble.
	abstract class CopyFlutterAotBundle extends Target {
	const CopyFlutterAotBundle();

	@override
	List<Source> get inputs => const <Source>[
	Source.pattern('{BUILD_DIR}/app.so'),
	];

	@override
	List<Source> get outputs => const <Source>[
	Source.pattern('{OUTPUT_DIR}/app.so'),
	];

	@override
	Future<void> build(Environment environment) async {
	final File outputFile = environment.outputDir.childFile('app.so');
	if (!outputFile.parent.existsSync()) {
	outputFile.parent.createSync(recursive: true);
	}
	environment.buildDir.childFile('app.so').copySync(outputFile.path);
	}
	}