Added module information to metadata and use by frontend_sever

- created class representing module metadata, added metadata to JsCode
  class
- added module information to metadata, such as module name, load
  function name
- added import and file uris for libraries
- added experimental-emit-debug-metadata flag to frontend_server
- added frontend server tests to check for saved metadata

Related: #41852
Closes: #40774
Change-Id: Iecbbf1e4eea1919e01f002f45363d30707cb1590
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/150181
Commit-Queue: Anna Gringauze <[email protected]>
Reviewed-by: Nicholas Shahan <[email protected]>
Reviewed-by: Gary Roumanis <[email protected]>

Author: Anna Gringauze

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

@@ -191,7 +191,7 @@ class DdcModuleBuilder extends _ModuleBuilder {
     }
 
     var resultModule = NamedFunction(
-        loadFunctionName(module.name),
+        loadFunctionIdentifier(module.name),
         js.fun("function(#) { 'use strict'; #; }", [parameters, statements]),
         true);
 
@@ -299,7 +299,7 @@ class AmdModuleBuilder extends _ModuleBuilder {
       statements.add(Return(ObjectInitializer(exportedProps, multiline: true)));
     }
     var resultModule = NamedFunction(
-        loadFunctionName(module.name),
+        loadFunctionIdentifier(module.name),
         js.fun("function(#) { 'use strict'; #; }", [fnParams, statements]),
         true);
     var block = js.statement(
@@ -309,6 +309,17 @@ class AmdModuleBuilder extends _ModuleBuilder {
   }
 }
 
+bool isSdkInternalRuntimeUri(Uri importUri) {
+  return importUri.scheme == 'dart' && importUri.path == '_runtime';
+}
+
+String libraryUriToJsIdentifier(Uri importUri) {
+  if (importUri.scheme == 'dart') {
+    return isSdkInternalRuntimeUri(importUri) ? 'dart' : importUri.path;
+  }
+  return pathToJSIdentifier(p.withoutExtension(importUri.pathSegments.last));
+}
+
 /// Converts an entire arbitrary path string into a string compatible with
 /// JS identifier naming rules while conserving path information.
 ///
@@ -327,9 +338,13 @@ String pathToJSIdentifier(String path) {
       .replaceAll('-', '_'));
 }
 
+/// Creates function name given [moduleName].
+String loadFunctionName(String moduleName) =>
+    'load__' + pathToJSIdentifier(moduleName.replaceAll('.', '_'));
+
 /// Creates function name identifier given [moduleName].
-Identifier loadFunctionName(String moduleName) =>
-    Identifier('load__' + pathToJSIdentifier(moduleName.replaceAll('.', '_')));
+Identifier loadFunctionIdentifier(String moduleName) =>
+    Identifier(loadFunctionName(moduleName));
 
 // Replacement string for path separators (i.e., '/', '\', '..').
 final encodedSeparator = '__';

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

@@ -61,6 +61,13 @@ class SharedCompilerOptions {
   /// runtime can enable synchronous stack trace deobsfuscation.
   final bool inlineSourceMap;
 
+  /// Whether to emit the debug metadata
+  ///
+  /// Debugger uses this information about to construct mapping between
+  /// modules and libraries that otherwise requires expensive communication with
+  /// the browser.
+  final bool emitDebugMetadata;
+
   /// Whether to emit a summary file containing API signatures.
   ///
   /// This is required for a modular build process.
@@ -99,6 +106,7 @@ class SharedCompilerOptions {
       this.summarizeApi = true,
       this.enableAsserts = true,
       this.replCompile = false,
+      this.emitDebugMetadata = false,
       this.summaryModules = const {},
       this.moduleFormats = const [],
       this.experiments = const {},
@@ -119,7 +127,9 @@ class SharedCompilerOptions {
             moduleFormats: parseModuleFormatOption(args),
             moduleName: _getModuleName(args, moduleRoot),
             replCompile: args['repl-compile'] as bool,
-            soundNullSafety: args['sound-null-safety'] as bool);
+            soundNullSafety: args['sound-null-safety'] as bool,
+            emitDebugMetadata:
+                args['experimental-emit-debug-metadata'] as bool);
 
   static void addArguments(ArgParser parser, {bool hide = true}) {
     addModuleFormatOptions(parser, hide: hide);
@@ -152,7 +162,14 @@ class SharedCompilerOptions {
       ..addFlag('sound-null-safety',
           help: 'Compile for sound null safety at runtime.',
           negatable: true,
-          defaultsTo: false);
+          defaultsTo: false)
+      // TODO(41852) Define a process for breaking changes before graduating from
+      // experimental.
+      ..addFlag('experimental-emit-debug-metadata',
+          help: 'Experimental option for compiler development.\n'
+              'Output a metadata file for debug tools next to the .js output.',
+          defaultsTo: false,
+          hide: true);
   }
 
   static String _getModuleName(ArgResults args, String moduleRoot) {

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

@@ -27,6 +27,7 @@ import '../js_ast/js_ast.dart' as js_ast;
 import '../js_ast/js_ast.dart' show js;
 import '../js_ast/source_map_printer.dart' show SourceMapPrintingContext;
 import 'compiler.dart';
+import 'module_metadata.dart';
 import 'target.dart';
 
 const _binaryName = 'dartdevc -k';
@@ -109,13 +110,6 @@ Future<CompilerResult> _compile(List<String> args,
         help: 'The path to the libraries.json file for the sdk.')
     ..addOption('used-inputs-file',
         help: 'If set, the file to record inputs used.', hide: true)
-    // TODO(41852) Define a process for breaking changes before graduating from
-    // experimental.
-    ..addFlag('experimental-emit-debug-metadata',
-        help: 'Experimental option for compiler development.\n'
-            'Output a metadata file for debug tools next to the .js output.',
-        defaultsTo: false,
-        hide: true)
     ..addFlag('kernel',
         abbr: 'k',
         help: 'Deprecated and ignored. To be removed in a future release.',
@@ -425,6 +419,7 @@ Future<CompilerResult> _compile(List<String> args,
     var jsCode = jsProgramToCode(jsModule, moduleFormat,
         buildSourceMap: options.sourceMap,
         inlineSourceMap: options.inlineSourceMap,
+        emitDebugMetadata: options.emitDebugMetadata,
         jsUrl: p.toUri(output).toString(),
         mapUrl: mapUrl,
         customScheme: multiRootScheme,
@@ -436,21 +431,9 @@ Future<CompilerResult> _compile(List<String> args,
       outFiles.add(
           File('$output.map').writeAsString(json.encode(jsCode.sourceMap)));
     }
-
-    if (argResults['experimental-emit-debug-metadata'] as bool) {
-      var moduleMetadata = [
-        for (var lib in compiledLibraries.libraries)
-          {
-            'name': compiler.jsLibraryName(lib),
-            'sourceMapFileUri': mapUrl,
-            'dartFileUris': [
-              lib.fileUri.toString(),
-              ...lib.parts.map((p) => p.partUri.toString())
-            ],
-          }
-      ];
+    if (jsCode.metadata != null) {
       outFiles.add(
-          File('$output.metadata').writeAsString(json.encode(moduleMetadata)));
+          File('$output.metadata').writeAsString(json.encode(jsCode.metadata)));
     }
   }
 
@@ -598,7 +581,14 @@ class JSCode {
   /// using [placeSourceMap].
   final Map sourceMap;
 
-  JSCode(this.code, this.sourceMap);
+  /// Module and library information
+  ///
+  /// The [metadata] is a contract between compiler and the debugger,
+  /// helping the debugger map between libraries, modules, source paths.
+  /// see: https://goto.google.com/dart-web-debugger-metadata
+  final ModuleMetadata metadata;
+
+  JSCode(this.code, this.sourceMap, {this.metadata});
 }
 
 /// Converts [moduleTree] to [JSCode], using [format].
@@ -608,6 +598,7 @@ class JSCode {
 JSCode jsProgramToCode(js_ast.Program moduleTree, ModuleFormat format,
     {bool buildSourceMap = false,
     bool inlineSourceMap = false,
+    bool emitDebugMetadata = false,
     String jsUrl,
     String mapUrl,
     String sourceMapBase,
@@ -666,7 +657,27 @@ JSCode jsProgramToCode(js_ast.Program moduleTree, ModuleFormat format,
   };
   text = text.replaceFirst(
       SharedCompiler.metricsLocationID, '$compileTimeStatistics');
-  return JSCode(text, builtMap);
+
+  var debugMetadata = emitDebugMetadata
+      ? _emitMetadata(moduleTree, component, mapUrl, jsUrl)
+      : null;
+
+  return JSCode(text, builtMap, metadata: debugMetadata);
+}
+
+ModuleMetadata _emitMetadata(js_ast.Program program, Component component,
+    String sourceMapUri, String moduleUri) {
+  var metadata = ModuleMetadata(
+      program.name, loadFunctionName(program.name), sourceMapUri, moduleUri);
+
+  for (var lib in component.libraries) {
+    metadata.addLibrary(LibraryMetadata(
+        libraryUriToJsIdentifier(lib.importUri),
+        lib.importUri.toString(),
+        lib.fileUri.toString(),
+        [...lib.parts.map((p) => p.partUri)]));
+  }
+  return metadata;
 }
 
 /// Parses Dart's non-standard `-Dname=value` syntax for declared variables,

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

@@ -17,7 +17,8 @@ import 'package:path/path.dart' as p;
 
 import '../compiler/js_names.dart' as js_ast;
 import '../compiler/js_utils.dart' as js_ast;
-import '../compiler/module_builder.dart' show pathToJSIdentifier;
+import '../compiler/module_builder.dart'
+    show isSdkInternalRuntimeUri, libraryUriToJsIdentifier, pathToJSIdentifier;
 import '../compiler/shared_command.dart' show SharedCompilerOptions;
 import '../compiler/shared_compiler.dart';
 import '../js_ast/js_ast.dart' as js_ast;
@@ -371,11 +372,7 @@ class ProgramCompiler extends ComputeOnceConstantVisitor<js_ast.Expression>
 
   @override
   String jsLibraryName(Library library) {
-    var uri = library.importUri;
-    if (uri.scheme == 'dart') {
-      return isSdkInternalRuntime(library) ? 'dart' : uri.path;
-    }
-    return pathToJSIdentifier(p.withoutExtension(uri.pathSegments.last));
+    return libraryUriToJsIdentifier(library.importUri);
   }
 
   @override
@@ -405,8 +402,7 @@ class ProgramCompiler extends ComputeOnceConstantVisitor<js_ast.Expression>
 
   @override
   bool isSdkInternalRuntime(Library l) {
-    var uri = l.importUri;
-    return uri.scheme == 'dart' && uri.path == '_runtime';
+    return isSdkInternalRuntimeUri(l.importUri);
   }
 
   @override