[dartdevc] add module-name option to kernel backend

This name is not used by most module formats, but we do use it with the
legacy format.

Change-Id: I8d2f36b12a60b37d0460b57d5a360ba21b4e0476
Reviewed-on: https://dart-review.googlesource.com/c/78923
Reviewed-by: Jake Macdonald <jakemac@google.com>
Commit-Queue: Jenny Messerly <jmesserly@google.com>

pkg/dev_compiler/lib/src/analyzer/code_generator.dart

@@ -48,7 +48,7 @@ import 'error_helpers.dart';
 import 'extension_types.dart' show ExtensionTypeSet;
 import 'js_interop.dart';
 import 'js_typerep.dart';
-import 'module_compiler.dart' show BuildUnit, CompilerOptions, JSModuleFile;
+import 'module_compiler.dart' show CompilerOptions, JSModuleFile;
 import 'nullable_type_inference.dart' show NullableTypeInference;
 import 'property_model.dart';
 import 'reify_coercions.dart' show CoercionReifier;
@@ -179,8 +179,6 @@ class CodeGenerator extends Object
 
   final _deferredProperties = HashMap<PropertyAccessorElement, JS.Method>();
 
-  BuildUnit _buildUnit;
-
   String _libraryRoot;
 
   bool _superAllowed = true;
@@ -250,29 +248,29 @@ class CodeGenerator extends Object
   ///
   /// Takes the metadata for the build unit, as well as resolved trees and
   /// errors, and computes the output module code and optionally the source map.
-  JSModuleFile compile(BuildUnit unit, List<CompilationUnit> compilationUnits) {
-    _buildUnit = unit;
-    _libraryRoot = _buildUnit.libraryRoot;
+  JSModuleFile compile(List<CompilationUnit> compilationUnits) {
+    _libraryRoot = options.libraryRoot;
     if (!_libraryRoot.endsWith(path.separator)) {
       _libraryRoot += path.separator;
     }
 
+    var name = options.moduleName;
     invalidModule() =>
-        JSModuleFile.invalid(unit.name, formatErrors(context, errors), options);
+        JSModuleFile.invalid(name, formatErrors(context, errors), options);
 
     if (!options.unsafeForceCompile && errors.any(_isFatalError)) {
       return invalidModule();
     }
 
     try {
-      var module = _emitModule(compilationUnits, unit.name);
+      var module = _emitModule(compilationUnits, name);
       if (!options.unsafeForceCompile && errors.any(_isFatalError)) {
         return invalidModule();
       }
 
       var dartApiSummary = _summarizeModule(compilationUnits);
-      return JSModuleFile(unit.name, formatErrors(context, errors), options,
-          module, dartApiSummary);
+      return JSModuleFile(
+          name, formatErrors(context, errors), options, module, dartApiSummary);
     } catch (e) {
       if (errors.any(_isFatalError)) {
         // Force compilation failed.  Suppress the exception and report
@@ -443,7 +441,7 @@ class CodeGenerator extends Object
     _copyAndFlattenBlocks(items, moduleItems);
 
     // Build the module.
-    return JS.Program(items, name: _buildUnit.name);
+    return JS.Program(items, name: options.moduleName);
   }
 
   void _emitDebuggerExtensionInfo(String name) {

pkg/dev_compiler/lib/src/analyzer/command.dart

@@ -12,7 +12,7 @@ import 'package:args/command_runner.dart' show UsageException;
 import 'package:path/path.dart' as path;
 
 import 'context.dart' show AnalyzerOptions;
-import 'module_compiler.dart' show BuildUnit, CompilerOptions, ModuleCompiler;
+import 'module_compiler.dart' show CompilerOptions, ModuleCompiler;
 
 const _binaryName = 'dartdevc';
 
@@ -103,12 +103,7 @@ ArgParser ddcArgParser({bool hide = true}) {
         help: 'Ignore unrecognized command line flags.',
         defaultsTo: false,
         hide: hide)
-    ..addMultiOption('out', abbr: 'o', help: 'Output file (required).')
-    ..addOption('module-name',
-        help: 'The output module name, used in some JS module formats.\n'
-            'Defaults to the output file name (without .js).')
-    ..addOption('library-root',
-        help: 'Root of source files. Library names are relative to this root.');
+    ..addMultiOption('out', abbr: 'o', help: 'Output file (required).');
   CompilerOptions.addArguments(argParser, hide: hide);
   defineAnalysisArguments(argParser, hide: hide, ddc: true);
   AnalyzerOptions.addArguments(argParser, hide: hide);
@@ -143,32 +138,7 @@ void _compile(ArgResults argResults, AnalyzerOptions analyzerOptions,
         '');
   }
 
-  // TODO(jmesserly): for now the first one is special. This will go away once
-  // we've removed the "root" and "module name" variables.
-  var firstOutPath = outPaths[0];
-
-  var libraryRoot = argResults['library-root'] as String;
-  if (libraryRoot != null) {
-    libraryRoot = path.absolute(libraryRoot);
-  } else {
-    libraryRoot = Directory.current.path;
-  }
-  var moduleName = argResults['module-name'] as String;
-  if (moduleName == null) {
-    var moduleRoot = compilerOpts.moduleRoot;
-    if (moduleRoot != null) {
-      // TODO(jmesserly): remove this legacy support after a deprecation period.
-      // (Mainly this is to give time for migrating build rules.)
-      moduleName =
-          path.withoutExtension(path.relative(firstOutPath, from: moduleRoot));
-    } else {
-      moduleName = path.basenameWithoutExtension(firstOutPath);
-    }
-  }
-
-  var unit = BuildUnit(moduleName, libraryRoot, argResults.rest);
-
-  var module = compiler.compile(unit, compilerOpts);
+  var module = compiler.compile(argResults.rest, compilerOpts);
   module.errors.forEach(printFn);
 
   if (!module.isValid) {

pkg/dev_compiler/lib/src/analyzer/module_compiler.dart

@@ -133,14 +133,14 @@ class ModuleCompiler {
   /// *Warning* - this may require resolving the entire world.
   /// If that is not desired, the analysis context must be pre-configured using
   /// summaries before calling this method.
-  JSModuleFile compile(BuildUnit unit, CompilerOptions options) {
+  JSModuleFile compile(List<String> sourcePaths, CompilerOptions options) {
     var trees = <CompilationUnit>[];
     var errors = <AnalysisError>[];
 
     var librariesToCompile = Queue<LibraryElement>();
 
     var compilingSdk = false;
-    for (var sourcePath in unit.sources) {
+    for (var sourcePath in sourcePaths) {
       var sourceUri = sourcePathToUri(sourcePath);
       if (sourceUri.scheme == "dart") {
         compilingSdk = true;
@@ -201,9 +201,9 @@ class ModuleCompiler {
       }
     }
 
-    var codeGenerator =
+    var compiler =
         CodeGenerator(context, summaryData, options, _extensionTypes, errors);
-    return codeGenerator.compile(unit, trees);
+    return compiler.compile(trees);
   }
 
   Iterable<AnalysisError> _filterJsErrors(
@@ -256,6 +256,10 @@ class CompilerOptions extends SharedCompilerOptions {
   /// [summaryModules].
   final String moduleRoot;
 
+  /// *deprecated* If specified, `dartdevc` will synthesize library names that
+  /// are relative to this path for all libraries in the JS module.
+  final String libraryRoot;
+
   CompilerOptions(
       {bool sourceMap = true,
       this.sourceMapComment = true,
@@ -269,7 +273,8 @@ class CompilerOptions extends SharedCompilerOptions {
       Map<String, String> bazelMapping = const {},
       this.summaryOutPath,
       Map<String, String> summaryModules = const {},
-      this.moduleRoot})
+      this.moduleRoot,
+      this.libraryRoot})
       : super(
             sourceMap: sourceMap,
             summarizeApi: summarizeApi,
@@ -286,6 +291,7 @@ class CompilerOptions extends SharedCompilerOptions {
         unsafeForceCompile = args['unsafe-force-compile'] as bool,
         summaryOutPath = args['summary-out'] as String,
         moduleRoot = args['module-root'] as String,
+        libraryRoot = _getLibraryRoot(args),
         super.fromArguments(args, args['module-root'] as String,
             args['summary-extension'] as String);
 
@@ -312,27 +318,15 @@ class CompilerOptions extends SharedCompilerOptions {
       ..addOption('module-root',
           help: '(deprecated) used to determine the default module name and\n'
               'summary import name if those are not provided.',
-          hide: hide);
+          hide: hide)
+      ..addOption('library-root',
+          help: '(deprecated) used to name libraries inside the module.');
   }
-}
 
-/// A unit of Dart code that can be built into a single JavaScript module.
-class BuildUnit {
-  /// The name of this module.
-  final String name;
-
-  /// All library names are relative to this path/prefix.
-  final String libraryRoot;
-
-  /// The list of sources in this module.
-  ///
-  /// The set of Dart files can be arbitrarily large, but it must contain
-  /// complete libraries including all of their parts, as well as all libraries
-  /// that are part of a library cycle.
-  final List<String> sources;
-
-  BuildUnit(String modulePath, this.libraryRoot, this.sources)
-      : name = '${path.toUri(modulePath)}';
+  static String _getLibraryRoot(ArgResults args) {
+    var root = args['library-root'] as String;
+    return root != null ? path.absolute(root) : path.current;
+  }
 }
 
 /// The output of Dart->JS compilation.

pkg/dev_compiler/lib/src/compiler/module_builder.dart

@@ -41,14 +41,11 @@ ModuleFormat parseModuleFormat(String s) => {
     }[s];
 
 /// Parse the module format option added by [addModuleFormatOptions].
-List<ModuleFormat> parseModuleFormatOption(ArgResults argResults) {
-  var format = argResults['modules'];
-  if (format is String) {
-    return [parseModuleFormat(format)];
-  }
-  var formats = (format as List<String>).map(parseModuleFormat).toList();
+List<ModuleFormat> parseModuleFormatOption(ArgResults args) {
+  var formats =
+      (args['modules'] as List<String>).map(parseModuleFormat).toList();
 
-  if (argResults['single-out-file'] as bool) {
+  if (args['single-out-file'] as bool) {
     for (int i = 0; i < formats.length; i++) {
       var format = formats[i];
       switch (formats[i]) {
@@ -72,8 +69,7 @@ List<ModuleFormat> parseModuleFormatOption(ArgResults argResults) {
 /// Adds an option to the [argParser] for choosing the module format, optionally
 /// [allowMultiple] formats to be specified, with each emitted into a separate
 /// file.
-void addModuleFormatOptions(ArgParser argParser,
-    {bool allowMultiple = false, bool hide = true}) {
+void addModuleFormatOptions(ArgParser argParser, {bool hide = true}) {
   argParser.addMultiOption('modules', help: 'module pattern to emit', allowed: [
     'es6',
     'common',

pkg/dev_compiler/lib/src/compiler/shared_command.dart

@@ -83,6 +83,13 @@ class SharedCompilerOptions {
 
   final List<ModuleFormat> moduleFormats;
 
+  /// The name of the module.
+  ///
+  /// This used when to support file concatenation. The JS module will contain
+  /// its module name inside itself, allowing it to declare the module name
+  /// independently of the file.
+  String moduleName;
+
   SharedCompilerOptions(
       {this.sourceMap = true,
       this.summarizeApi = true,
@@ -91,7 +98,8 @@ class SharedCompilerOptions {
       this.replCompile = false,
       this.bazelMapping = const {},
       this.summaryModules = const {},
-      this.moduleFormats = const []});
+      this.moduleFormats = const [],
+      this.moduleName});
 
   SharedCompilerOptions.fromArguments(ArgResults args,
       [String moduleRoot, String summaryExtension])
@@ -104,10 +112,11 @@ class SharedCompilerOptions {
                 _parseBazelMappings(args['bazel-mapping'] as List<String>),
             summaryModules: _parseCustomSummaryModules(
                 args['summary'] as List<String>, moduleRoot, summaryExtension),
-            moduleFormats: parseModuleFormatOption(args));
+            moduleFormats: parseModuleFormatOption(args),
+            moduleName: _getModuleName(args, moduleRoot));
 
   static void addArguments(ArgParser parser, {bool hide = true}) {
-    addModuleFormatOptions(parser, allowMultiple: true, hide: hide);
+    addModuleFormatOptions(parser, hide: hide);
 
     parser
       ..addMultiOption('summary',
@@ -122,6 +131,9 @@ class SharedCompilerOptions {
           help: 'emit metadata annotations queriable via mirrors', hide: hide)
       ..addFlag('enable-asserts',
           help: 'enable assertions', defaultsTo: true, hide: hide)
+      ..addOption('module-name',
+          help: 'The output module name, used in some JS module formats.\n'
+              'Defaults to the output file name (without .js).')
       // TODO(jmesserly): rename this, it has nothing to do with bazel.
       ..addMultiOption('bazel-mapping',
           help: '--bazel-mapping=gen/to/library.dart,to/library.dart\n'
@@ -129,6 +141,32 @@ class SharedCompilerOptions {
           splitCommas: false,
           hide: hide);
   }
+
+  static String _getModuleName(ArgResults args, String moduleRoot) {
+    var moduleName = args['module-name'] as String;
+    if (moduleName == null) {
+      var outPaths = args['out'];
+      var outPath = outPaths is String
+          ? outPaths
+          : (outPaths as List<String>)
+              .firstWhere((_) => true, orElse: () => null);
+
+      if (moduleRoot != null) {
+        // TODO(jmesserly): remove this legacy support after a deprecation period.
+        // (Mainly this is to give time for migrating build rules.)
+        moduleName =
+            path.withoutExtension(path.relative(outPath, from: moduleRoot));
+      } else {
+        moduleName = path.basenameWithoutExtension(outPath);
+      }
+    }
+    // TODO(jmesserly): this should probably use sourcePathToUri.
+    //
+    // Also we should not need this logic if the user passed in the module name
+    // explicitly. It is here for backwards compatibility until we can confirm
+    // that build systems do not depend on passing windows-style paths here.
+    return path.toUri(moduleName).toString();
+  }
 }
 
 /// Finds explicit module names of the form `path=name` in [summaryPaths],

pkg/dev_compiler/lib/src/kernel/command.dart

@@ -221,6 +221,11 @@ Future<CompilerResult> _compile(List<String> args,
   var jsModule =
       compiler.emitModule(component, result.inputSummaries, summaryModules);
 
+  // TODO(jmesserly): support for multiple output formats?
+  //
+  // Also the old Analyzer backend had some code to make debugging better when
+  // --single-out-file is used, but that option does not appear to be used by
+  // any of our build systems.
   var jsCode = jsProgramToCode(jsModule, options.moduleFormats.first,
       buildSourceMap: argResults['source-map'] as bool,
       jsUrl: path.toUri(output).toString(),

pkg/dev_compiler/lib/src/kernel/compiler.dart

@@ -234,12 +234,12 @@ class ProgramCompiler extends Object
 
   bool get emitMetadata => options.emitMetadata;
 
-  JS.Program emitModule(Component buildUnit, List<Component> summaries,
+  JS.Program emitModule(Component component, List<Component> summaries,
       Map<Uri, String> summaryModules) {
     if (moduleItems.isNotEmpty) {
       throw StateError('Can only call emitModule once.');
     }
-    _component = buildUnit;
+    _component = component;
 
     var moduleImports = summaryModules.values.toList();
     for (var i = 0; i < summaries.length; i++) {
@@ -252,7 +252,7 @@ class ProgramCompiler extends Object
       }
     }
 
-    var libraries = buildUnit.libraries.where((l) => !l.isExternal);
+    var libraries = component.libraries.where((l) => !l.isExternal);
     var ddcRuntime =
         libraries.firstWhere(isSdkInternalRuntime, orElse: () => null);
     if (ddcRuntime != null) {
@@ -335,7 +335,7 @@ class ProgramCompiler extends Object
     _copyAndFlattenBlocks(items, moduleItems);
 
     // Build the module.
-    return JS.Program(items, name: buildUnit.root.name);
+    return JS.Program(items, name: options.moduleName);
   }
 
   /// Flattens blocks in [items] to a single list.

pkg/dev_compiler/tool/kernel_sdk.dart

@@ -52,9 +52,11 @@ Future main(List<String> args) async {
   await Directory(outputDir).create(recursive: true);
   await writeComponentToBinary(component, outputPath);
 
-  var jsModule =
-      ProgramCompiler(component, target.hierarchy, SharedCompilerOptions(), {})
-          .emitModule(component, [], {});
+  var jsModule = ProgramCompiler(
+      component,
+      target.hierarchy,
+      SharedCompilerOptions(moduleName: 'dart_sdk'),
+      {}).emitModule(component, [], {});
   var moduleFormats = {
     'amd': ModuleFormat.amd,
     'common': ModuleFormat.common,

pkg/dev_compiler/web/web_command.dart

@@ -293,15 +293,14 @@ class WebCompileCommand extends Command {
       }
       resources.newFile(fileName, sourceCode);
 
-      var unit = BuildUnit(libraryName, "", [fileName]);
-
-      JSModuleFile module = compiler.compile(unit, compilerOptions);
+      compilerOptions.moduleName = path.toUri(libraryName).toString();
+      JSModuleFile module = compiler.compile([fileName], compilerOptions);
 
       var moduleCode = '';
       if (module.isValid) {
-        moduleCode = module
-            .getCode(ModuleFormat.legacyConcat, unit.name, unit.name + '.map')
-            .code;
+        var name = compilerOptions.moduleName;
+        moduleCode =
+            module.getCode(ModuleFormat.legacyConcat, name, name + '.map').code;
       }
 
       return CompileResult(