[flutter_tools] restore report timings functionality to build aot (#52918)

packages/flutter_tools/lib/src/aot.dart

@@ -30,6 +30,7 @@ class AotBuilder {
     bool bitcode = kBitcodeEnabledDefault,
     bool quiet = true,
     Iterable<DarwinArch> iosBuildArchs = defaultIOSArchs,
+    bool reportTimings,
   }) async {
     if (platform == null) {
       throwToolExit('No AOT build platform specified');
@@ -106,6 +107,21 @@ class AotBuilder {
       throwToolExit('The aot build failed.');
     }
 
+    // This print output is used by the dart team for build benchmarks.
+    if (reportTimings) {
+      final PerformanceMeasurement kernel = result.performance['kernel_snapshot'];
+      PerformanceMeasurement aot;
+      if (expectSo) {
+        aot = result.performance.values.firstWhere(
+          (PerformanceMeasurement measurement) => measurement.analyicsName == 'android_aot');
+      } else {
+        aot = result.performance.values.firstWhere(
+          (PerformanceMeasurement measurement) => measurement.analyicsName == 'ios_aot');
+      }
+      globals.printStatus('frontend(CompileTime): ${kernel.elapsedMilliseconds} ms.');
+      globals.printStatus('snapshot(CompileTime): ${aot.elapsedMilliseconds} ms.');
+    }
+
     if (expectSo) {
       environment.buildDir.childFile('app.so')
         .copySync(globals.fs.path.join(outputPath, 'app.so'));

packages/flutter_tools/lib/src/build_system/build_system.dart

@@ -114,6 +114,14 @@ abstract class Target {
   /// argument to build a particular target.
   String get name;
 
+  /// A name that measurements can be categorized under for this [Target].
+  ///
+  /// Unlike [name], this is not expected to be unique, so multiple targets
+  /// that are conceptually the same can share an analytics name.
+  ///
+  /// If not provided, defaults to [name]
+  String get analyticsName => name;
+
   /// The dependencies of this target.
   List<Target> get dependencies;
 
@@ -594,7 +602,12 @@ class _BuildInstance {
       resource.release();
       stopwatch.stop();
       stepTimings[node.target.name] = PerformanceMeasurement(
-          node.target.name, stopwatch.elapsedMilliseconds, skipped, passed);
+        target: node.target.name,
+        elapsedMilliseconds: stopwatch.elapsedMilliseconds,
+        skipped: skipped,
+        passed: passed,
+        analyicsName: node.target.analyticsName,
+      );
     }
     return passed;
   }
@@ -617,11 +630,19 @@ class ExceptionMeasurement {
 
 /// Helper class to collect measurement data.
 class PerformanceMeasurement {
-  PerformanceMeasurement(this.target, this.elapsedMilliseconds, this.skipped, this.passed);
+  PerformanceMeasurement({
+    @required this.target,
+    @required this.elapsedMilliseconds,
+    @required this.skipped,
+    @required this.passed,
+    @required this.analyicsName,
+  });
+
   final int elapsedMilliseconds;
   final String target;
   final bool skipped;
   final bool passed;
+  final String analyicsName;
 }
 
 /// Check if there are any dependency cycles in the target.

packages/flutter_tools/lib/src/build_system/targets/dart.dart

@@ -257,6 +257,9 @@ class KernelSnapshot extends Target {
 abstract class AotElfBase extends Target {
   const AotElfBase();
 
+  @override
+  String get analyticsName => 'android_aot';
+
   @override
   Future<void> build(Environment environment) async {
     final AOTSnapshotter snapshotter = AOTSnapshotter(

packages/flutter_tools/lib/src/build_system/targets/ios.dart

@@ -26,6 +26,9 @@ import 'icon_tree_shaker.dart';
 abstract class AotAssemblyBase extends Target {
   const AotAssemblyBase();
 
+  @override
+  String get analyticsName => 'ios_aot';
+
   @override
   Future<void> build(Environment environment) async {
     final AOTSnapshotter snapshotter = AOTSnapshotter(

packages/flutter_tools/lib/src/commands/build_aot.dart

@@ -45,7 +45,8 @@ class BuildAotCommand extends BuildSubCommand with TargetPlatformBasedDevelopmen
         defaultsTo: kBitcodeEnabledDefault,
         help: 'Build the AOT bundle with bitcode. Requires a compatible bitcode engine.',
         hide: true,
-      );
+      )
+      ..addFlag('report-timings', hide: true);
   }
 
   AotBuilder aotBuilder;
@@ -76,6 +77,7 @@ class BuildAotCommand extends BuildSubCommand with TargetPlatformBasedDevelopmen
       bitcode: boolArg('bitcode'),
       quiet: boolArg('quiet'),
       iosBuildArchs: stringsArg('ios-arch').map<DarwinArch>(getIOSArchForName),
+      reportTimings: boolArg('report-timings'),
     );
     return FlutterCommandResult.success();
   }

packages/flutter_tools/test/general.shard/build_system/targets/android_test.dart

@@ -22,6 +22,10 @@ void main() {
     Platform: () => FakePlatform(operatingSystem: 'linux', environment: const <String, String>{}),
   });
 
+  test('Android AOT targets has analyicsName', () {
+    expect(androidArmProfile.analyticsName, 'android_aot');
+  });
+
   testbed.test('debug bundle contains expected resources', () async {
     final Environment environment = Environment.test(
       globals.fs.currentDirectory,

packages/flutter_tools/test/general.shard/build_system/targets/ios_test.dart

@@ -45,6 +45,11 @@ void main() {
     });
   });
 
+  test('iOS AOT targets has analyicsName', () {
+    expect(const AotAssemblyRelease().analyticsName, 'ios_aot');
+    expect(const AotAssemblyProfile().analyticsName, 'ios_aot');
+  });
+
   test('DebugUniveralFramework creates expected binary with arm64 only arch', () => testbed.run(() async {
     environment.defines[kIosArchs] = 'arm64';
     processManager = FakeProcessManager.list(<FakeCommand>[

packages/flutter_tools/test/general.shard/commands/build_aot_test.dart

@@ -3,10 +3,12 @@
 // found in the LICENSE file.
 
 import 'package:file/memory.dart';
+import 'package:flutter_tools/src/aot.dart';
 import 'package:flutter_tools/src/artifacts.dart';
 import 'package:flutter_tools/src/base/process.dart';
 import 'package:flutter_tools/src/build_info.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
+import 'package:flutter_tools/src/build_system/build_system.dart';
 import 'package:flutter_tools/src/ios/bitcode.dart';
 import 'package:flutter_tools/src/ios/plist_parser.dart';
 import 'package:flutter_tools/src/macos/xcode.dart';
@@ -106,6 +108,48 @@ void main() {
     PlistParser: () => mockPlistUtils,
   });
 
+  testUsingContext('build aot outputs timing info', () async {
+    globals.fs.file('.dart_tool/flutter_build/cce09742720db17ffec62331bd7e42d5/app.so')
+      .createSync(recursive: true);
+    when(buildSystem.build(any, any))
+      .thenAnswer((Invocation invocation) async {
+        return BuildResult(success: true, performance: <String, PerformanceMeasurement>{
+          'kernel_snapshot': PerformanceMeasurement(
+            analyicsName: 'kernel_snapshot',
+            target: 'kernel_snapshot',
+            elapsedMilliseconds: 1000,
+            passed: true,
+            skipped: false,
+          ),
+          'anything': PerformanceMeasurement(
+            analyicsName: 'android_aot',
+            target: 'anything',
+            elapsedMilliseconds: 1000,
+            passed: true,
+            skipped: false,
+          ),
+        });
+      });
+
+    await AotBuilder().build(
+      platform: TargetPlatform.android_arm64,
+      outputPath: '/',
+      buildInfo: BuildInfo.release,
+      mainDartFile: globals.fs.path.join('lib', 'main.dart'),
+      reportTimings: true,
+    );
+
+    expect(testLogger.statusText, allOf(
+      contains('frontend(CompileTime): 1000 ms.'),
+      contains('snapshot(CompileTime): 1000 ms.'),
+    ));
+  }, overrides: <Type, Generator>{
+    BuildSystem: () => MockBuildSystem(),
+    FileSystem: () => MemoryFileSystem.test(),
+    ProcessManager: () => FakeProcessManager.any(),
+  });
+
+
   testUsingContext('build aot can parse valid Xcode Clang version (11)', () async {
     final Directory flutterFramework = memoryFileSystem.directory('ios_profile/Flutter.framework')
       ..createSync(recursive: true);
@@ -227,3 +271,4 @@ void main() {
 
 class MockXcode extends Mock implements Xcode {}
 class MockPlistUtils extends Mock implements PlistParser {}
+class MockBuildSystem extends Mock implements BuildSystem {}