pkg/front_end/lib/src/api_prototype/compiler_options.dart - sdk.git - Git at Google

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // 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.

 library front_end.compiler_options;

 import 'package:_fe_analyzer_shared/src/messages/diagnostic_message.dart'
     show DiagnosticMessage, DiagnosticMessageHandler;
 import 'package:_fe_analyzer_shared/src/messages/severity.dart' show Severity;

 import 'package:kernel/ast.dart' show Version;

 import 'package:kernel/default_language_version.dart' as kernel
     show defaultLanguageVersion;

 import 'package:kernel/target/targets.dart' show Target;

 import '../base/nnbd_mode.dart';

 import 'experimental_flags.dart'
     show
         AllowedExperimentalFlags,
         defaultExperimentalFlags,
         ExperimentalFlag,
         expiredExperimentalFlags,
         parseExperimentalFlag;

 import 'experimental_flags.dart' as flags
     show
         getExperimentEnabledVersionInLibrary,
         isExperimentEnabled,
         isExperimentEnabledInLibrary,
         isExperimentEnabledInLibraryByVersion;

 import 'file_system.dart' show FileSystem;

 import 'standard_file_system.dart' show StandardFileSystem;

 import '../api_unstable/util.dart';

 export 'package:_fe_analyzer_shared/src/messages/diagnostic_message.dart'
     show DiagnosticMessage;

 /// Front-end options relevant to compiler back ends.
 ///
 /// Not intended to be implemented or extended by clients.
 class CompilerOptions {
   /// The URI of the root of the Dart SDK (typically a "file:" URI).
   ///
   /// If `null`, the SDK will be searched for using
   /// [Platform.resolvedExecutable] as a starting point.
   Uri? sdkRoot;

   /// Uri to a platform libraries specification file.
   ///
   /// A libraries specification file is a JSON file that describes how to map
   /// `dart:*` libraries to URIs in the underlying [fileSystem].  See
   /// `package:front_end/src/base/libraries_specification.dart` for details on
   /// the format.
   ///
   /// If a value is not specified and `compileSdk = true`, the compiler will
   /// infer at a default location under [sdkRoot], typically under
   /// `lib/libraries.json`.
   Uri? librariesSpecificationUri;

   DiagnosticMessageHandler? onDiagnostic;

   /// URI of the ".dart_tool/package_config.json" or ".packages" file
   /// (typically a "file:" URI).
   ///
   /// If a ".packages" file is given and a ".dart_tool/package_config.json" file
   /// exists next to it, the ".dart_tool/package_config.json" file is used
   /// instead.
   ///
   /// If `null`, the file will be found via the standard package_config search
   /// algorithm.
   ///
   /// If the URI's path component is empty (e.g. `new Uri()`), no packages file
   /// will be used.
   Uri? packagesFileUri;

   /// URIs of additional dill files.
   ///
   /// These will be loaded and linked into the output.
   ///
   /// The components provided here should be closed: any libraries that they
   /// reference should be defined in a component in [additionalDills] or
   /// [sdkSummary].
   List<Uri> additionalDills = [];

   /// URI of the SDK summary file (typically a "file:" URI).
   ///
   /// This should should be a summary previously generated by this package (and
   /// not the similarly named summary files from `package:analyzer`.)
   ///
   /// If `null` and [compileSdk] is false, the SDK summary will be searched for
   /// at a default location within [sdkRoot].
   Uri? sdkSummary;

   /// The declared variables for use by configurable imports and constant
   /// evaluation.
   Map<String, String>? declaredVariables;

   /// The [FileSystem] which should be used by the front end to access files.
   ///
   /// All file system access performed by the front end goes through this
   /// mechanism, with one exception: if no value is specified for
   /// [packagesFileUri], the packages file is located using the actual physical
   /// file system.  TODO(paulberry): fix this.
   FileSystem fileSystem = StandardFileSystem.instance;

   /// Whether to generate code for the SDK.
   ///
   /// By default the front end resolves components using a prebuilt SDK summary.
   /// When this option is `true`, [sdkSummary] must be null.
   bool compileSdk = false;

   /// Enable or disable experimental features. Features mapping to `true` are
   /// explicitly enabled. Features mapping to `false` are explicitly disabled.
   /// Features not mentioned in the map will have their default value.
   Map<ExperimentalFlag, bool> explicitExperimentalFlags =
       <ExperimentalFlag, bool>{};

   Map<ExperimentalFlag, bool>? defaultExperimentFlagsForTesting;
   AllowedExperimentalFlags? allowedExperimentalFlagsForTesting;
   Map<ExperimentalFlag, Version>? experimentEnabledVersionForTesting;
   Map<ExperimentalFlag, Version>? experimentReleasedVersionForTesting;

   /// Environment map used when evaluating `bool.fromEnvironment`,
   /// `int.fromEnvironment` and `String.fromEnvironment` during constant
   /// evaluation. If the map is `null`, all environment constants will be left
   /// unevaluated and can be evaluated by a constant evaluator later.
   Map<String, String>? environmentDefines = null;

   /// Report an error if a constant could not be evaluated (either because it
   /// is an environment constant and no environment was specified, or because
   /// it refers to a constructor or variable initializer that is not available).
   bool errorOnUnevaluatedConstant = false;

   /// The target platform that will consume the compiled code.
   ///
   /// Used to provide platform-specific details to the compiler like:
   ///   * the set of libraries are part of a platform's SDK (e.g. dart:html for
   ///     dart2js, dart:ui for flutter).
   ///
   ///   * what kernel transformations should be applied to the component
   ///     (async/await, mixin inlining, etc).
   ///
   ///   * how to deal with non-standard features like `native` extensions.
   ///
   /// If not specified, the default target is the VM.
   Target? target;

   /// Whether to show verbose messages (mainly for debugging and performance
   /// tracking).
   ///
   /// Messages are printed on stdout.
   // TODO(sigmund): improve the diagnostics API to provide mechanism to
   // intercept verbose data (Issue #30056)
   bool verbose = false;

   /// Whether to run extra verification steps to validate that compiled
   /// components are well formed.
   ///
   /// Errors are reported via the [onDiagnostic] callback.
   bool verify = false;

   /// Whether to - if verifying - skip the platform.
   bool skipPlatformVerification = false;

   /// Whether to dump generated components in a text format (also mainly for
   /// debugging).
   ///
   /// Dumped data is printed in stdout.
   bool debugDump = false;

   /// Whether to omit the platform when serializing the result from a `fasta
   /// compile` run.
   bool omitPlatform = false;

   /// Whether to set the exit code to non-zero if any problem (including
   /// warning, etc.) is encountered during compilation.
   bool setExitCodeOnProblem = false;

   /// Whether to embed the input sources in generated kernel components.
   ///
   /// The kernel `Component` API includes a `uriToSource` map field that is used
   /// to embed the entire contents of the source files. This part of the kernel
   /// API is in flux and it is not necessary for some tools. Today it is used
   /// for translating error locations and stack traces in the VM.
   // TODO(sigmund): change the default.
   bool embedSourceText = true;

   /// Whether the compiler should throw as soon as it encounters a
   /// compilation error.
   ///
   /// Typically used by developers to debug internals of the compiler.
   bool throwOnErrorsForDebugging = false;

   /// Whether the compiler should throw as soon as it encounters a
   /// compilation warning.
   ///
   /// Typically used by developers to debug internals of the compiler.
   bool throwOnWarningsForDebugging = false;

   /// For the [throwOnErrorsForDebugging] or [throwOnWarningsForDebugging]
   /// options, skip this number of otherwise fatal diagnostics without throwing.
   /// I.e. the default value of 0 means throw on the first fatal diagnostic.
   ///
   /// If the value is negative, print a stack trace for every fatal
   /// diagnostic, but do not stop the compilation.
   int skipForDebugging = 0;

   /// Whether to write a file (e.g. a dill file) when reporting a crash.
   bool writeFileOnCrashReport = true;

   /// Whether nnbd weak, strong or agnostic mode is used if experiment
   /// 'non-nullable' is enabled.
   NnbdMode nnbdMode = NnbdMode.Weak;

   /// Whether to emit a warning when a ReachabilityError is thrown to ensure
   /// soundness in mixed mode.
   bool warnOnReachabilityCheck = false;

   /// The current sdk version string, e.g. "2.6.0-edge.sha1hash".
   /// For instance used for language versioning (specifying the maximum
   /// version).
   String currentSdkVersion = "${kernel.defaultLanguageVersion.major}"
       "."
       "${kernel.defaultLanguageVersion.minor}";

   /// If `true`, a '.d' file with input dependencies is generated when
   /// compiling the platform dill.
   bool emitDeps = true;

   /// Set of invocation modes the describe how the compilation is performed.
   ///
   /// This used to selectively emit certain messages depending on how the
   /// CFE is invoked. For instance to emit a message about the null safety
   /// compilation mode when the modes includes [InvocationMode.compile].
   Set<InvocationMode> invocationModes = {};

   /// Verbosity level used for filtering emitted messages.
   Verbosity verbosity = Verbosity.all;

   /// Returns `true` if the experiment with the given [flag] is enabled, either
   /// explicitly or implicitly.
   ///
   /// Note that libraries can still opt out of the experiment by having a lower
   /// language version than required for the experiment.
   bool isExperimentEnabled(ExperimentalFlag flag) {
     return flags.isExperimentEnabled(flag,
         explicitExperimentalFlags: explicitExperimentalFlags,
         defaultExperimentFlagsForTesting: defaultExperimentFlagsForTesting);
   }

   /// Returns `true` if the experiment with the given [flag] is enabled either
   /// explicitly or implicitly for the library with the given [importUri].
   ///
   /// Note that the library can still opt out of the experiment by having a
   /// lower language version than required for the experiment. See
   /// [getExperimentEnabledVersionInLibrary].
   bool isExperimentEnabledInLibrary(ExperimentalFlag flag, Uri importUri) {
     return flags.isExperimentEnabledInLibrary(flag, importUri,
         defaultExperimentFlagsForTesting: defaultExperimentFlagsForTesting,
         explicitExperimentalFlags: explicitExperimentalFlags,
         allowedExperimentalFlags: allowedExperimentalFlagsForTesting);
   }

   /// Returns the minimum language version needed for a library with the given
   /// [importUri] to opt in to the experiment with the given [flag].
   ///
   /// Note that the experiment might not be enabled at all for the library, as
   /// computed by [isExperimentEnabledInLibrary].
   Version getExperimentEnabledVersionInLibrary(
       ExperimentalFlag flag, Uri importUri) {
     return flags.getExperimentEnabledVersionInLibrary(
         flag, importUri, explicitExperimentalFlags,
         defaultExperimentFlagsForTesting: defaultExperimentFlagsForTesting,
         allowedExperimentalFlags: allowedExperimentalFlagsForTesting,
         experimentEnabledVersionForTesting: experimentEnabledVersionForTesting,
         experimentReleasedVersionForTesting:
             experimentReleasedVersionForTesting);
   }

   /// Return `true` if the experiment with the given [flag] is enabled for the
   /// library with the given [importUri] and language [version].
   bool isExperimentEnabledInLibraryByVersion(
       ExperimentalFlag flag, Uri importUri, Version version) {
     return flags.isExperimentEnabledInLibraryByVersion(flag, importUri, version,
         explicitExperimentalFlags: explicitExperimentalFlags,
         defaultExperimentFlagsForTesting: defaultExperimentFlagsForTesting,
         allowedExperimentalFlags: allowedExperimentalFlagsForTesting,
         experimentEnabledVersionForTesting: experimentEnabledVersionForTesting,
         experimentReleasedVersionForTesting:
             experimentReleasedVersionForTesting);
   }

   bool equivalent(CompilerOptions other,
       {bool ignoreOnDiagnostic: true,
       bool ignoreVerbose: true,
       bool ignoreVerify: true,
       bool ignoreDebugDump: true}) {
     if (sdkRoot != other.sdkRoot) return false;
     if (librariesSpecificationUri != other.librariesSpecificationUri) {
       return false;
     }
     if (!ignoreOnDiagnostic) {
       if (onDiagnostic != other.onDiagnostic) return false;
     }
     if (packagesFileUri != other.packagesFileUri) return false;
     if (!equalLists(additionalDills, other.additionalDills)) return false;
     if (sdkSummary != other.sdkSummary) return false;
     if (!equalMaps(declaredVariables, other.declaredVariables)) return false;
     if (fileSystem != other.fileSystem) return false;
     if (compileSdk != compileSdk) return false;
     // chaseDependencies aren't used anywhere, so ignored here.
     // targetPatches aren't used anywhere, so ignored here.
     if (!equalMaps(
         explicitExperimentalFlags, other.explicitExperimentalFlags)) {
       return false;
     }
     if (!equalMaps(environmentDefines, other.environmentDefines)) return false;
     if (errorOnUnevaluatedConstant != other.errorOnUnevaluatedConstant) {
       return false;
     }
     if (target != other.target) {
       if (target.runtimeType != other.target.runtimeType) return false;
       if (target?.name != other.target?.name) return false;
       if (target?.flags != other.target?.flags) return false;
     }
     // enableAsserts is not used anywhere, so ignored here.
     if (!ignoreVerbose) {
       if (verbose != other.verbose) return false;
     }
     if (!ignoreVerify) {
       if (verify != other.verify) return false;
       if (skipPlatformVerification != other.skipPlatformVerification) {
         return false;
       }
     }
     if (!ignoreDebugDump) {
       if (debugDump != other.debugDump) return false;
     }
     if (omitPlatform != other.omitPlatform) return false;
     if (setExitCodeOnProblem != other.setExitCodeOnProblem) return false;
     if (embedSourceText != other.embedSourceText) return false;
     if (throwOnErrorsForDebugging != other.throwOnErrorsForDebugging) {
       return false;
     }
     if (throwOnWarningsForDebugging != other.throwOnWarningsForDebugging) {
       return false;
     }
     if (skipForDebugging != other.skipForDebugging) return false;
     if (writeFileOnCrashReport != other.writeFileOnCrashReport) return false;
     if (nnbdMode != other.nnbdMode) return false;
     if (currentSdkVersion != other.currentSdkVersion) return false;
     if (emitDeps != other.emitDeps) return false;
     if (!equalSets(invocationModes, other.invocationModes)) return false;

     return true;
   }
 }

 /// Parse experimental flag arguments of the form 'flag' or 'no-flag' into a map
 /// from 'flag' to `true` or `false`, respectively.
 Map<String, bool> parseExperimentalArguments(Iterable<String>? arguments) {
   Map<String, bool> result = {};
   if (arguments != null) {
     for (String argument in arguments) {
       for (String feature in argument.split(',')) {
         if (feature.startsWith('no-')) {
           result[feature.substring(3)] = false;
         } else {
           result[feature] = true;
         }
       }
     }
   }
   return result;
 }

 /// Parse a map of experimental flags to values that can be passed to
 /// [CompilerOptions.explicitExperimentalFlags].
 ///
 /// If an unknown flag is mentioned, or a flag is mentioned more than once,
 /// the supplied error handler is called with an error message.
 ///
 /// If an expired flag is set to its non-default value the supplied error
 /// handler is called with an error message.
 ///
 /// If an expired flag is set to its default value the supplied warning
 /// handler is called with a warning message.
 Map<ExperimentalFlag, bool> parseExperimentalFlags(
     Map<String, bool>? experiments,
     {required void Function(String message) onError,
     void Function(String message)? onWarning}) {
   Map<ExperimentalFlag, bool> flags = <ExperimentalFlag, bool>{};
   if (experiments != null) {
     for (String experiment in experiments.keys) {
       bool value = experiments[experiment]!;
       ExperimentalFlag? flag = parseExperimentalFlag(experiment);
       if (flag == null) {
         onError("Unknown experiment: " + experiment);
       } else if (flags.containsKey(flag)) {
         if (flags[flag] != value) {
           onError(
               "Experiment specified with conflicting values: " + experiment);
         }
       } else {
         if (expiredExperimentalFlags[flag]!) {
           if (value != defaultExperimentalFlags[flag]) {
             /// Produce an error when the value is not the default value.
             if (value) {
               onError("Enabling experiment " +
                   experiment +
                   " is no longer supported.");
             } else {
               onError("Disabling experiment " +
                   experiment +
                   " is no longer supported.");
             }
             value = defaultExperimentalFlags[flag]!;
           } else if (onWarning != null) {
             /// Produce a warning when the value is the default value.
             if (value) {
               onWarning("Experiment " +
                   experiment +
                   " is enabled by default. "
                       "The use of the flag is deprecated.");
             } else {
               onWarning("Experiment " +
                   experiment +
                   " is disabled by default. "
                       "The use of the flag is deprecated.");
             }
           }
           flags[flag] = value;
         } else {
           flags[flag] = value;
         }
       }
     }
   }
   return flags;
 }

 class InvocationMode {
   /// This mode is used for when the CFE is invoked in order to compile an
   /// executable.
   ///
   /// If used, a message about the null safety compilation mode will be emitted.
   static const InvocationMode compile = const InvocationMode('compile');

   final String name;

   const InvocationMode(this.name);

   /// Returns the set of information modes from a comma-separated list of
   /// invocation mode names.
   ///
   /// If a name isn't recognized and [onError] is provided, [onError] is called
   /// with an error messages and an empty set of invocation modes is returned.
   ///
   /// If a name isn't recognized and [onError] isn't provided, an error is
   /// thrown.
   static Set<InvocationMode> parseArguments(String arg,
       {void Function(String)? onError}) {
     Set<InvocationMode> result = {};
     for (String name in arg.split(',')) {
       if (name.isNotEmpty) {
         InvocationMode? mode = fromName(name);
         if (mode == null) {
           String message = "Unknown invocation mode '$name'.";
           if (onError != null) {
             onError(message);
           } else {
             throw new UnsupportedError(message);
           }
         } else {
           result.add(mode);
         }
       }
     }
     return result;
   }

   /// Returns the [InvocationMode] with the given [name].
   static InvocationMode? fromName(String name) {
     for (InvocationMode invocationMode in values) {
       if (name == invocationMode.name) {
         return invocationMode;
       }
     }
     return null;
   }

   static const List<InvocationMode> values = const [compile];
 }

 /// Verbosity level used for filtering messages during compilation.
 class Verbosity {
   /// Only error messages are emitted.
   static const Verbosity error =
       const Verbosity('error', 'Show only error messages');

   /// Error and warning messages are emitted.
   static const Verbosity warning =
       const Verbosity('warning', 'Show only error and warning messages');

   /// Error, warning, and info messages are emitted.
   static const Verbosity info =
       const Verbosity('info', 'Show error, warning, and info messages');

   /// All messages are emitted.
   static const Verbosity all = const Verbosity('all', 'Show all messages');

   static const List<Verbosity> values = const [error, warning, info, all];

   /// Returns the names of all options.
   static List<String> get allowedValues =>
       [for (Verbosity value in values) value.name];

   /// Returns a map from option name to option help messages.
   static Map<String, String> get allowedValuesHelp =>
       {for (Verbosity value in values) value.name: value.help};

   /// Returns the verbosity corresponding to the given [name].
   ///
   /// If [name] isn't recognized and [onError] is provided, [onError] is called
   /// with an error messages and [defaultValue] is returned.
   ///
   /// If [name] isn't recognized and [onError] isn't provided, an error is
   /// thrown.
   static Verbosity parseArgument(String name,
       {void Function(String)? onError, Verbosity defaultValue: Verbosity.all}) {
     for (Verbosity verbosity in values) {
       if (name == verbosity.name) {
         return verbosity;
       }
     }
     String message = "Unknown verbosity '$name'.";
     if (onError != null) {
       onError(message);
       return defaultValue;
     }
     throw new UnsupportedError(message);
   }

   static bool shouldPrint(Verbosity verbosity, DiagnosticMessage message) {
     Severity severity = message.severity;
     switch (verbosity) {
       case Verbosity.error:
         switch (severity) {
           case Severity.internalProblem:
           case Severity.error:
             return true;
           case Severity.warning:
           case Severity.info:
           case Severity.context:
           case Severity.ignored:
             return false;
         }
       case Verbosity.warning:
         switch (severity) {
           case Severity.internalProblem:
           case Severity.error:
           case Severity.warning:
             return true;
           case Severity.info:
           case Severity.context:
           case Severity.ignored:
             return false;
         }
       case Verbosity.info:
         switch (severity) {
           case Severity.internalProblem:
           case Severity.error:
           case Severity.warning:
           case Severity.info:
             return true;
           case Severity.context:
           case Severity.ignored:
             return false;
         }
       case Verbosity.all:
         return true;
     }
     throw new UnsupportedError(
         "Unsupported verbosity $verbosity and severity $severity.");
   }

   static const String defaultValue = 'all';

   final String name;
   final String help;

   const Verbosity(this.name, this.help);

   @override
   String toString() => 'Verbosity($name)';
 }
	// Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file
	// 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.

	library front_end.compiler_options;

	import 'package:_fe_analyzer_shared/src/messages/diagnostic_message.dart'
	show DiagnosticMessage, DiagnosticMessageHandler;
	import 'package:_fe_analyzer_shared/src/messages/severity.dart' show Severity;

	import 'package:kernel/ast.dart' show Version;

	import 'package:kernel/default_language_version.dart' as kernel
	show defaultLanguageVersion;

	import 'package:kernel/target/targets.dart' show Target;

	import '../base/nnbd_mode.dart';

	import 'experimental_flags.dart'
	show
	AllowedExperimentalFlags,
	defaultExperimentalFlags,
	ExperimentalFlag,
	expiredExperimentalFlags,
	parseExperimentalFlag;

	import 'experimental_flags.dart' as flags
	show
	getExperimentEnabledVersionInLibrary,
	isExperimentEnabled,
	isExperimentEnabledInLibrary,
	isExperimentEnabledInLibraryByVersion;

	import 'file_system.dart' show FileSystem;

	import 'standard_file_system.dart' show StandardFileSystem;

	import '../api_unstable/util.dart';

	export 'package:_fe_analyzer_shared/src/messages/diagnostic_message.dart'
	show DiagnosticMessage;

	/// Front-end options relevant to compiler back ends.
	///
	/// Not intended to be implemented or extended by clients.
	class CompilerOptions {
	/// The URI of the root of the Dart SDK (typically a "file:" URI).
	///
	/// If `null`, the SDK will be searched for using
	/// [Platform.resolvedExecutable] as a starting point.
	Uri? sdkRoot;

	/// Uri to a platform libraries specification file.
	///
	/// A libraries specification file is a JSON file that describes how to map
	/// `dart:*` libraries to URIs in the underlying [fileSystem]. See
	/// `package:front_end/src/base/libraries_specification.dart` for details on
	/// the format.
	///
	/// If a value is not specified and `compileSdk = true`, the compiler will
	/// infer at a default location under [sdkRoot], typically under
	/// `lib/libraries.json`.
	Uri? librariesSpecificationUri;

	DiagnosticMessageHandler? onDiagnostic;

	/// URI of the ".dart_tool/package_config.json" or ".packages" file
	/// (typically a "file:" URI).
	///
	/// If a ".packages" file is given and a ".dart_tool/package_config.json" file
	/// exists next to it, the ".dart_tool/package_config.json" file is used
	/// instead.
	///
	/// If `null`, the file will be found via the standard package_config search
	/// algorithm.
	///
	/// If the URI's path component is empty (e.g. `new Uri()`), no packages file
	/// will be used.
	Uri? packagesFileUri;

	/// URIs of additional dill files.
	///
	/// These will be loaded and linked into the output.
	///
	/// The components provided here should be closed: any libraries that they
	/// reference should be defined in a component in [additionalDills] or
	/// [sdkSummary].
	List<Uri> additionalDills = [];

	/// URI of the SDK summary file (typically a "file:" URI).
	///
	/// This should should be a summary previously generated by this package (and
	/// not the similarly named summary files from `package:analyzer`.)
	///
	/// If `null` and [compileSdk] is false, the SDK summary will be searched for
	/// at a default location within [sdkRoot].
	Uri? sdkSummary;

	/// The declared variables for use by configurable imports and constant
	/// evaluation.
	Map<String, String>? declaredVariables;

	/// The [FileSystem] which should be used by the front end to access files.
	///
	/// All file system access performed by the front end goes through this
	/// mechanism, with one exception: if no value is specified for
	/// [packagesFileUri], the packages file is located using the actual physical
	/// file system. TODO(paulberry): fix this.
	FileSystem fileSystem = StandardFileSystem.instance;

	/// Whether to generate code for the SDK.
	///
	/// By default the front end resolves components using a prebuilt SDK summary.
	/// When this option is `true`, [sdkSummary] must be null.
	bool compileSdk = false;

	/// Enable or disable experimental features. Features mapping to `true` are
	/// explicitly enabled. Features mapping to `false` are explicitly disabled.
	/// Features not mentioned in the map will have their default value.
	Map<ExperimentalFlag, bool> explicitExperimentalFlags =
	<ExperimentalFlag, bool>{};

	Map<ExperimentalFlag, bool>? defaultExperimentFlagsForTesting;
	AllowedExperimentalFlags? allowedExperimentalFlagsForTesting;
	Map<ExperimentalFlag, Version>? experimentEnabledVersionForTesting;
	Map<ExperimentalFlag, Version>? experimentReleasedVersionForTesting;

	/// Environment map used when evaluating `bool.fromEnvironment`,
	/// `int.fromEnvironment` and `String.fromEnvironment` during constant
	/// evaluation. If the map is `null`, all environment constants will be left
	/// unevaluated and can be evaluated by a constant evaluator later.
	Map<String, String>? environmentDefines = null;

	/// Report an error if a constant could not be evaluated (either because it
	/// is an environment constant and no environment was specified, or because
	/// it refers to a constructor or variable initializer that is not available).
	bool errorOnUnevaluatedConstant = false;

	/// The target platform that will consume the compiled code.
	///
	/// Used to provide platform-specific details to the compiler like:
	/// * the set of libraries are part of a platform's SDK (e.g. dart:html for
	/// dart2js, dart:ui for flutter).
	///
	/// * what kernel transformations should be applied to the component
	/// (async/await, mixin inlining, etc).
	///
	/// * how to deal with non-standard features like `native` extensions.
	///
	/// If not specified, the default target is the VM.
	Target? target;

	/// Whether to show verbose messages (mainly for debugging and performance
	/// tracking).
	///
	/// Messages are printed on stdout.
	// TODO(sigmund): improve the diagnostics API to provide mechanism to
	// intercept verbose data (Issue #30056)
	bool verbose = false;

	/// Whether to run extra verification steps to validate that compiled
	/// components are well formed.
	///
	/// Errors are reported via the [onDiagnostic] callback.
	bool verify = false;

	/// Whether to - if verifying - skip the platform.
	bool skipPlatformVerification = false;

	/// Whether to dump generated components in a text format (also mainly for
	/// debugging).
	///
	/// Dumped data is printed in stdout.
	bool debugDump = false;

	/// Whether to omit the platform when serializing the result from a `fasta
	/// compile` run.
	bool omitPlatform = false;

	/// Whether to set the exit code to non-zero if any problem (including
	/// warning, etc.) is encountered during compilation.
	bool setExitCodeOnProblem = false;

	/// Whether to embed the input sources in generated kernel components.
	///
	/// The kernel `Component` API includes a `uriToSource` map field that is used
	/// to embed the entire contents of the source files. This part of the kernel
	/// API is in flux and it is not necessary for some tools. Today it is used
	/// for translating error locations and stack traces in the VM.
	// TODO(sigmund): change the default.
	bool embedSourceText = true;

	/// Whether the compiler should throw as soon as it encounters a
	/// compilation error.
	///
	/// Typically used by developers to debug internals of the compiler.
	bool throwOnErrorsForDebugging = false;

	/// Whether the compiler should throw as soon as it encounters a
	/// compilation warning.
	///
	/// Typically used by developers to debug internals of the compiler.
	bool throwOnWarningsForDebugging = false;

	/// For the [throwOnErrorsForDebugging] or [throwOnWarningsForDebugging]
	/// options, skip this number of otherwise fatal diagnostics without throwing.
	/// I.e. the default value of 0 means throw on the first fatal diagnostic.
	///
	/// If the value is negative, print a stack trace for every fatal
	/// diagnostic, but do not stop the compilation.
	int skipForDebugging = 0;

	/// Whether to write a file (e.g. a dill file) when reporting a crash.
	bool writeFileOnCrashReport = true;

	/// Whether nnbd weak, strong or agnostic mode is used if experiment
	/// 'non-nullable' is enabled.
	NnbdMode nnbdMode = NnbdMode.Weak;

	/// Whether to emit a warning when a ReachabilityError is thrown to ensure
	/// soundness in mixed mode.
	bool warnOnReachabilityCheck = false;

	/// The current sdk version string, e.g. "2.6.0-edge.sha1hash".
	/// For instance used for language versioning (specifying the maximum
	/// version).
	String currentSdkVersion = "${kernel.defaultLanguageVersion.major}"
	"."
	"${kernel.defaultLanguageVersion.minor}";

	/// If `true`, a '.d' file with input dependencies is generated when
	/// compiling the platform dill.
	bool emitDeps = true;

	/// Set of invocation modes the describe how the compilation is performed.
	///
	/// This used to selectively emit certain messages depending on how the
	/// CFE is invoked. For instance to emit a message about the null safety
	/// compilation mode when the modes includes [InvocationMode.compile].
	Set<InvocationMode> invocationModes = {};

	/// Verbosity level used for filtering emitted messages.
	Verbosity verbosity = Verbosity.all;

	/// Returns `true` if the experiment with the given [flag] is enabled, either
	/// explicitly or implicitly.
	///
	/// Note that libraries can still opt out of the experiment by having a lower
	/// language version than required for the experiment.
	bool isExperimentEnabled(ExperimentalFlag flag) {
	return flags.isExperimentEnabled(flag,
	explicitExperimentalFlags: explicitExperimentalFlags,
	defaultExperimentFlagsForTesting: defaultExperimentFlagsForTesting);
	}

	/// Returns `true` if the experiment with the given [flag] is enabled either
	/// explicitly or implicitly for the library with the given [importUri].
	///
	/// Note that the library can still opt out of the experiment by having a
	/// lower language version than required for the experiment. See
	/// [getExperimentEnabledVersionInLibrary].
	bool isExperimentEnabledInLibrary(ExperimentalFlag flag, Uri importUri) {
	return flags.isExperimentEnabledInLibrary(flag, importUri,
	defaultExperimentFlagsForTesting: defaultExperimentFlagsForTesting,
	explicitExperimentalFlags: explicitExperimentalFlags,
	allowedExperimentalFlags: allowedExperimentalFlagsForTesting);
	}

	/// Returns the minimum language version needed for a library with the given
	/// [importUri] to opt in to the experiment with the given [flag].
	///
	/// Note that the experiment might not be enabled at all for the library, as
	/// computed by [isExperimentEnabledInLibrary].
	Version getExperimentEnabledVersionInLibrary(
	ExperimentalFlag flag, Uri importUri) {
	return flags.getExperimentEnabledVersionInLibrary(
	flag, importUri, explicitExperimentalFlags,
	defaultExperimentFlagsForTesting: defaultExperimentFlagsForTesting,
	allowedExperimentalFlags: allowedExperimentalFlagsForTesting,
	experimentEnabledVersionForTesting: experimentEnabledVersionForTesting,
	experimentReleasedVersionForTesting:
	experimentReleasedVersionForTesting);
	}

	/// Return `true` if the experiment with the given [flag] is enabled for the
	/// library with the given [importUri] and language [version].
	bool isExperimentEnabledInLibraryByVersion(
	ExperimentalFlag flag, Uri importUri, Version version) {
	return flags.isExperimentEnabledInLibraryByVersion(flag, importUri, version,
	explicitExperimentalFlags: explicitExperimentalFlags,
	defaultExperimentFlagsForTesting: defaultExperimentFlagsForTesting,
	allowedExperimentalFlags: allowedExperimentalFlagsForTesting,
	experimentEnabledVersionForTesting: experimentEnabledVersionForTesting,
	experimentReleasedVersionForTesting:
	experimentReleasedVersionForTesting);
	}

	bool equivalent(CompilerOptions other,
	{bool ignoreOnDiagnostic: true,
	bool ignoreVerbose: true,
	bool ignoreVerify: true,
	bool ignoreDebugDump: true}) {
	if (sdkRoot != other.sdkRoot) return false;
	if (librariesSpecificationUri != other.librariesSpecificationUri) {
	return false;
	}
	if (!ignoreOnDiagnostic) {
	if (onDiagnostic != other.onDiagnostic) return false;
	}
	if (packagesFileUri != other.packagesFileUri) return false;
	if (!equalLists(additionalDills, other.additionalDills)) return false;
	if (sdkSummary != other.sdkSummary) return false;
	if (!equalMaps(declaredVariables, other.declaredVariables)) return false;
	if (fileSystem != other.fileSystem) return false;
	if (compileSdk != compileSdk) return false;
	// chaseDependencies aren't used anywhere, so ignored here.
	// targetPatches aren't used anywhere, so ignored here.
	if (!equalMaps(
	explicitExperimentalFlags, other.explicitExperimentalFlags)) {
	return false;
	}
	if (!equalMaps(environmentDefines, other.environmentDefines)) return false;
	if (errorOnUnevaluatedConstant != other.errorOnUnevaluatedConstant) {
	return false;
	}
	if (target != other.target) {
	if (target.runtimeType != other.target.runtimeType) return false;
	if (target?.name != other.target?.name) return false;
	if (target?.flags != other.target?.flags) return false;
	}
	// enableAsserts is not used anywhere, so ignored here.
	if (!ignoreVerbose) {
	if (verbose != other.verbose) return false;
	}
	if (!ignoreVerify) {
	if (verify != other.verify) return false;
	if (skipPlatformVerification != other.skipPlatformVerification) {
	return false;
	}
	}
	if (!ignoreDebugDump) {
	if (debugDump != other.debugDump) return false;
	}
	if (omitPlatform != other.omitPlatform) return false;
	if (setExitCodeOnProblem != other.setExitCodeOnProblem) return false;
	if (embedSourceText != other.embedSourceText) return false;
	if (throwOnErrorsForDebugging != other.throwOnErrorsForDebugging) {
	return false;
	}
	if (throwOnWarningsForDebugging != other.throwOnWarningsForDebugging) {
	return false;
	}
	if (skipForDebugging != other.skipForDebugging) return false;
	if (writeFileOnCrashReport != other.writeFileOnCrashReport) return false;
	if (nnbdMode != other.nnbdMode) return false;
	if (currentSdkVersion != other.currentSdkVersion) return false;
	if (emitDeps != other.emitDeps) return false;
	if (!equalSets(invocationModes, other.invocationModes)) return false;

	return true;
	}
	}

	/// Parse experimental flag arguments of the form 'flag' or 'no-flag' into a map
	/// from 'flag' to `true` or `false`, respectively.
	Map<String, bool> parseExperimentalArguments(Iterable<String>? arguments) {
	Map<String, bool> result = {};
	if (arguments != null) {
	for (String argument in arguments) {
	for (String feature in argument.split(',')) {
	if (feature.startsWith('no-')) {
	result[feature.substring(3)] = false;
	} else {
	result[feature] = true;
	}
	}
	}
	}
	return result;
	}

	/// Parse a map of experimental flags to values that can be passed to
	/// [CompilerOptions.explicitExperimentalFlags].
	///
	/// If an unknown flag is mentioned, or a flag is mentioned more than once,
	/// the supplied error handler is called with an error message.
	///
	/// If an expired flag is set to its non-default value the supplied error
	/// handler is called with an error message.
	///
	/// If an expired flag is set to its default value the supplied warning
	/// handler is called with a warning message.
	Map<ExperimentalFlag, bool> parseExperimentalFlags(
	Map<String, bool>? experiments,
	{required void Function(String message) onError,
	void Function(String message)? onWarning}) {
	Map<ExperimentalFlag, bool> flags = <ExperimentalFlag, bool>{};
	if (experiments != null) {
	for (String experiment in experiments.keys) {
	bool value = experiments[experiment]!;
	ExperimentalFlag? flag = parseExperimentalFlag(experiment);
	if (flag == null) {
	onError("Unknown experiment: " + experiment);
	} else if (flags.containsKey(flag)) {
	if (flags[flag] != value) {
	onError(
	"Experiment specified with conflicting values: " + experiment);
	}
	} else {
	if (expiredExperimentalFlags[flag]!) {
	if (value != defaultExperimentalFlags[flag]) {
	/// Produce an error when the value is not the default value.
	if (value) {
	onError("Enabling experiment " +
	experiment +
	" is no longer supported.");
	} else {
	onError("Disabling experiment " +
	experiment +
	" is no longer supported.");
	}
	value = defaultExperimentalFlags[flag]!;
	} else if (onWarning != null) {
	/// Produce a warning when the value is the default value.
	if (value) {
	onWarning("Experiment " +
	experiment +
	" is enabled by default. "
	"The use of the flag is deprecated.");
	} else {
	onWarning("Experiment " +
	experiment +
	" is disabled by default. "
	"The use of the flag is deprecated.");
	}
	}
	flags[flag] = value;
	} else {
	flags[flag] = value;
	}
	}
	}
	}
	return flags;
	}

	class InvocationMode {
	/// This mode is used for when the CFE is invoked in order to compile an
	/// executable.
	///
	/// If used, a message about the null safety compilation mode will be emitted.
	static const InvocationMode compile = const InvocationMode('compile');

	final String name;

	const InvocationMode(this.name);

	/// Returns the set of information modes from a comma-separated list of
	/// invocation mode names.
	///
	/// If a name isn't recognized and [onError] is provided, [onError] is called
	/// with an error messages and an empty set of invocation modes is returned.
	///
	/// If a name isn't recognized and [onError] isn't provided, an error is
	/// thrown.
	static Set<InvocationMode> parseArguments(String arg,
	{void Function(String)? onError}) {
	Set<InvocationMode> result = {};
	for (String name in arg.split(',')) {
	if (name.isNotEmpty) {
	InvocationMode? mode = fromName(name);
	if (mode == null) {
	String message = "Unknown invocation mode '$name'.";
	if (onError != null) {
	onError(message);
	} else {
	throw new UnsupportedError(message);
	}
	} else {
	result.add(mode);
	}
	}
	}
	return result;
	}

	/// Returns the [InvocationMode] with the given [name].
	static InvocationMode? fromName(String name) {
	for (InvocationMode invocationMode in values) {
	if (name == invocationMode.name) {
	return invocationMode;
	}
	}
	return null;
	}

	static const List<InvocationMode> values = const [compile];
	}

	/// Verbosity level used for filtering messages during compilation.
	class Verbosity {
	/// Only error messages are emitted.
	static const Verbosity error =
	const Verbosity('error', 'Show only error messages');

	/// Error and warning messages are emitted.
	static const Verbosity warning =
	const Verbosity('warning', 'Show only error and warning messages');

	/// Error, warning, and info messages are emitted.
	static const Verbosity info =
	const Verbosity('info', 'Show error, warning, and info messages');

	/// All messages are emitted.
	static const Verbosity all = const Verbosity('all', 'Show all messages');

	static const List<Verbosity> values = const [error, warning, info, all];

	/// Returns the names of all options.
	static List<String> get allowedValues =>
	[for (Verbosity value in values) value.name];

	/// Returns a map from option name to option help messages.
	static Map<String, String> get allowedValuesHelp =>
	{for (Verbosity value in values) value.name: value.help};

	/// Returns the verbosity corresponding to the given [name].
	///
	/// If [name] isn't recognized and [onError] is provided, [onError] is called
	/// with an error messages and [defaultValue] is returned.
	///
	/// If [name] isn't recognized and [onError] isn't provided, an error is
	/// thrown.
	static Verbosity parseArgument(String name,
	{void Function(String)? onError, Verbosity defaultValue: Verbosity.all}) {
	for (Verbosity verbosity in values) {
	if (name == verbosity.name) {
	return verbosity;
	}
	}
	String message = "Unknown verbosity '$name'.";
	if (onError != null) {
	onError(message);
	return defaultValue;
	}
	throw new UnsupportedError(message);
	}

	static bool shouldPrint(Verbosity verbosity, DiagnosticMessage message) {
	Severity severity = message.severity;
	switch (verbosity) {
	case Verbosity.error:
	switch (severity) {
	case Severity.internalProblem:
	case Severity.error:
	return true;
	case Severity.warning:
	case Severity.info:
	case Severity.context:
	case Severity.ignored:
	return false;
	}
	case Verbosity.warning:
	switch (severity) {
	case Severity.internalProblem:
	case Severity.error:
	case Severity.warning:
	return true;
	case Severity.info:
	case Severity.context:
	case Severity.ignored:
	return false;
	}
	case Verbosity.info:
	switch (severity) {
	case Severity.internalProblem:
	case Severity.error:
	case Severity.warning:
	case Severity.info:
	return true;
	case Severity.context:
	case Severity.ignored:
	return false;
	}
	case Verbosity.all:
	return true;
	}
	throw new UnsupportedError(
	"Unsupported verbosity $verbosity and severity $severity.");
	}

	static const String defaultValue = 'all';

	final String name;
	final String help;

	const Verbosity(this.name, this.help);

	@override
	String toString() => 'Verbosity($name)';
	}