Add --track-widget-creation flag to frontend_server.

This is needed to activate the kernel transformer embedded with the kernel package from the flutter engine.

Change-Id: I3253e01723b662eb48b4b3743ac5bcc1b44c7d46
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/102920
Reviewed-by: Jake Macdonald <jakemac@google.com>
Reviewed-by: Aske Simon Christensen <askesc@google.com>
Commit-Queue: Jacob Richman <jacobr@google.com>

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

@@ -11,6 +11,7 @@ import 'package:build_integration/file_system/multi_root.dart';
 import 'package:cli_util/cli_util.dart' show getSdkPath;
 import 'package:front_end/src/api_unstable/ddc.dart' as fe;
 import 'package:kernel/kernel.dart' hide MapEntry;
+import 'package:kernel/target/targets.dart';
 import 'package:kernel/text/ast_to_text.dart' as kernel show Printer;
 import 'package:kernel/binary/ast_to_binary.dart' as kernel show BinaryPrinter;
 import 'package:path/path.dart' as path;
@@ -226,7 +227,8 @@ Future<CompilerResult> _compile(List<String> args,
         sourcePathToUri(packageFile),
         sourcePathToUri(librarySpecPath),
         summaryModules.keys.toList(),
-        DevCompilerTarget(trackWidgetCreation: trackWidgetCreation),
+        DevCompilerTarget(
+            TargetFlags(trackWidgetCreation: trackWidgetCreation)),
         fileSystem: fileSystem,
         experiments: experiments);
   } else {
@@ -238,7 +240,8 @@ Future<CompilerResult> _compile(List<String> args,
         sourcePathToUri(packageFile),
         sourcePathToUri(librarySpecPath),
         summaryModules.keys.toList(),
-        DevCompilerTarget(trackWidgetCreation: trackWidgetCreation),
+        DevCompilerTarget(
+            TargetFlags(trackWidgetCreation: trackWidgetCreation)),
         fileSystem: fileSystem,
         experiments: experiments);
     incrementalCompiler = compilerState.incrementalCompiler;

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

@@ -14,9 +14,9 @@ import 'kernel_helpers.dart';
 
 /// A kernel [Target] to configure the Dart Front End for dartdevc.
 class DevCompilerTarget extends Target {
-  DevCompilerTarget({this.trackWidgetCreation = false});
+  DevCompilerTarget(this.flags);
 
-  final bool trackWidgetCreation;
+  final TargetFlags flags;
 
   ClassHierarchy hierarchy;
 
@@ -103,7 +103,7 @@ class DevCompilerTarget extends Target {
       List<Library> libraries,
       DiagnosticReporter diagnosticReporter,
       {void logger(String msg)}) {
-    if (trackWidgetCreation) {
+    if (flags.trackWidgetCreation) {
       WidgetCreatorTracker().transform(component, libraries);
     }
   }

pkg/dev_compiler/test/nullable_inference_test.dart

@@ -8,6 +8,7 @@ import 'package:front_end/src/api_unstable/ddc.dart' as fe;
 import 'package:kernel/core_types.dart';
 import 'package:kernel/kernel.dart';
 import 'package:kernel/class_hierarchy.dart';
+import 'package:kernel/target/targets.dart';
 import 'package:test/test.dart';
 
 import 'package:dev_compiler/src/kernel/command.dart';
@@ -575,8 +576,8 @@ const nullCheck = const _NullCheck();
   var mainUri = Uri.file('/memory/test.dart');
   _fileSystem.entityForUri(mainUri).writeAsStringSync(code);
   var oldCompilerState = _compilerState;
-  _compilerState = await fe.initializeCompiler(
-      oldCompilerState, sdkUri, packagesUri, null, [], DevCompilerTarget(),
+  _compilerState = await fe.initializeCompiler(oldCompilerState, sdkUri,
+      packagesUri, null, [], DevCompilerTarget(TargetFlags()),
       fileSystem: _fileSystem, experiments: const {});
   if (!identical(oldCompilerState, _compilerState)) inference = null;
   fe.DdcResult result =

pkg/dev_compiler/tool/kernel_sdk.dart

@@ -16,6 +16,7 @@ import 'package:dev_compiler/src/kernel/compiler.dart';
 import 'package:front_end/src/api_unstable/ddc.dart'
     show CompilerOptions, kernelForComponent;
 import 'package:kernel/kernel.dart';
+import 'package:kernel/target/targets.dart';
 import 'package:path/path.dart' as path;
 
 Future main(List<String> args) async {
@@ -38,7 +39,7 @@ Future main(List<String> args) async {
 
   var librarySpecPath = parserOptions['libraries'] as String;
 
-  var target = DevCompilerTarget();
+  var target = DevCompilerTarget(TargetFlags());
   var options = CompilerOptions()
     ..compileSdk = true
     // TODO(sigmund): remove this unnecessary option when possible.

pkg/kernel/lib/target/targets.dart

@@ -11,8 +11,9 @@ final List<String> targetNames = targets.keys.toList();
 
 class TargetFlags {
   final bool legacyMode;
+  final bool trackWidgetCreation;
 
-  TargetFlags({this.legacyMode: false});
+  TargetFlags({this.legacyMode = false, this.trackWidgetCreation = false});
 }
 
 typedef Target _TargetBuilder(TargetFlags flags);

pkg/vm/lib/frontend_server.dart

@@ -113,6 +113,9 @@ ArgParser argParser = new ArgParser(allowTrailingOptions: true)
           'improved speed.',
       defaultsTo: false,
       hide: true)
+  ..addFlag('track-widget-creation',
+      help: 'Run a kernel transformer to track creation locations for widgets.',
+      defaultsTo: false)
   ..addMultiOption('enable-experiment',
       help: 'Comma separated list of experimental features, eg set-literals.',
       hide: true);
@@ -319,7 +322,10 @@ class FrontendCompiler implements CompilerInterface {
       return false;
     }
 
-    compilerOptions.target = createFrontEndTarget(options['target']);
+    compilerOptions.target = createFrontEndTarget(
+      options['target'],
+      trackWidgetCreation: options['track-widget-creation'],
+    );
     if (compilerOptions.target == null) {
       print('Failed to create front-end target ${options['target']}.');
       return false;

pkg/vm/lib/kernel_front_end.dart

@@ -534,11 +534,13 @@ bool parseCommandLineDefines(
 }
 
 /// Create front-end target with given name.
-Target createFrontEndTarget(String targetName) {
+Target createFrontEndTarget(String targetName,
+    {bool trackWidgetCreation = false}) {
   // Make sure VM-specific targets are available.
   installAdditionalTargets();
 
-  final TargetFlags targetFlags = new TargetFlags();
+  final TargetFlags targetFlags =
+      new TargetFlags(trackWidgetCreation: trackWidgetCreation);
   return getTarget(targetName, targetFlags);
 }
 

pkg/vm/lib/target/flutter.dart

@@ -10,10 +10,7 @@ import 'package:kernel/transformations/track_widget_constructor_locations.dart';
 import 'package:vm/target/vm.dart' show VmTarget;
 
 class FlutterTarget extends VmTarget {
-  FlutterTarget(TargetFlags flags, {this.trackWidgetCreation = false})
-      : super(flags);
-
-  final bool trackWidgetCreation;
+  FlutterTarget(TargetFlags flags) : super(flags);
 
   @override
   String get name => 'flutter';
@@ -55,7 +52,7 @@ class FlutterTarget extends VmTarget {
       List<Library> libraries,
       DiagnosticReporter diagnosticReporter,
       {void logger(String msg)}) {
-    if (trackWidgetCreation) {
+    if (flags.trackWidgetCreation) {
       new WidgetCreatorTracker().transform(component, libraries);
     }
   }

utils/bazel/kernel_worker.dart

@@ -128,7 +128,7 @@ final summaryArgsParser = new ArgParser()
   ..addOption('output')
   ..addFlag('reuse-compiler-result', defaultsTo: false)
   ..addFlag('use-incremental-compiler', defaultsTo: false)
-  ..addFlag('track-kernel-creation', defaultsTo: false);
+  ..addFlag('track-widget-creation', defaultsTo: false);
 
 class ComputeKernelResult {
   final bool succeeded;
@@ -172,13 +172,13 @@ Future<ComputeKernelResult> computeKernel(List<String> args,
   var excludeNonSources = parsedArgs['exclude-non-sources'] as bool;
 
   var summaryOnly = parsedArgs['summary-only'] as bool;
-  var trackKernelCreation = parsedArgs['track-kernel-creation'] as bool;
+  var trackWidgetCreation = parsedArgs['track-widget-creation'] as bool;
 
   // TODO(sigmund,jakemac): make target mandatory. We allow null to be backwards
   // compatible while we migrate existing clients of this tool.
   var targetName =
       (parsedArgs['target'] as String) ?? (summaryOnly ? 'ddc' : 'vm');
-  var targetFlags = new TargetFlags();
+  var targetFlags = new TargetFlags(trackWidgetCreation: trackWidgetCreation);
   Target target;
   switch (targetName) {
     case 'vm':
@@ -188,8 +188,7 @@ Future<ComputeKernelResult> computeKernel(List<String> args,
       }
       break;
     case 'flutter':
-      target = new FlutterTarget(targetFlags,
-          trackWidgetCreation: trackKernelCreation);
+      target = new FlutterTarget(targetFlags);
       if (summaryOnly) {
         throw new ArgumentError(
             'error: --summary-only not supported for the flutter target');
@@ -212,8 +211,8 @@ Future<ComputeKernelResult> computeKernel(List<String> args,
     case 'ddc':
       // TODO(jakemac):If `generateKernel` changes to return a summary
       // component, process the component instead.
-      target = new DevCompilerSummaryTarget(sources, excludeNonSources,
-          trackWidgetCreation: trackKernelCreation);
+      target =
+          new DevCompilerSummaryTarget(sources, excludeNonSources, targetFlags);
       if (!summaryOnly) {
         out.writeln('error: --no-summary-only not supported for the '
             'ddc target');
@@ -332,9 +331,9 @@ class DevCompilerSummaryTarget extends DevCompilerTarget {
   final List<Uri> sources;
   final bool excludeNonSources;
 
-  DevCompilerSummaryTarget(this.sources, this.excludeNonSources,
-      {trackWidgetCreation = false})
-      : super(trackWidgetCreation: trackWidgetCreation);
+  DevCompilerSummaryTarget(
+      this.sources, this.excludeNonSources, TargetFlags targetFlags)
+      : super(targetFlags);
 
   @override
   void performOutlineTransformations(Component component) {