Revert "Skip AOT snapshot build if inputs are unchanged" (#11463)

* Revert "Support space- and backslash-escaped dependencies (#11090)"

This reverts commit e6bafd0b.

* Revert "Skip AOT snapshot build if inputs are unchanged (#11084)"

This reverts commit b5e522e2.

packages/flutter_tools/lib/src/base/build.dart

@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:async';
 import 'dart:convert' show JSON;
 
 import 'package:crypto/crypto.dart' show md5;
@@ -43,28 +42,3 @@ class Checksum {
   @override
   int get hashCode => _checksums.hashCode;
 }
-
-final RegExp _separatorExpr = new RegExp(r'([^\\]) ');
-final RegExp _escapeExpr = new RegExp(r'\\(.)');
-
-/// Parses a VM snapshot dependency file.
-///
-/// Snapshot dependency files are a single line mapping the output snapshot to a
-/// space-separated list of input files used to generate that output. Spaces and
-/// backslashes are escaped with a backslash. e.g,
-///
-/// outfile : file1.dart fil\\e2.dart fil\ e3.dart
-///
-/// will return a set containing: 'file1.dart', 'fil\e2.dart', 'fil e3.dart'.
-Future<Set<String>> readDepfile(String depfilePath) async {
-  // Depfile format:
-  // outfile1 outfile2 : file1.dart file2.dart file3.dart
-  final String contents = await fs.file(depfilePath).readAsString();
-  final String dependencies = contents.split(': ')[1];
-  return dependencies
-      .replaceAllMapped(_separatorExpr, (Match match) => '${match.group(1)}\n')
-      .split('\n')
-      .map((String path) => path.replaceAllMapped(_escapeExpr, (Match match) => match.group(1)).trim())
-      .where((String path) => path.isNotEmpty)
-      .toSet();
-}

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

@@ -5,7 +5,6 @@
 import 'dart:async';
 
 import '../artifacts.dart';
-import '../base/build.dart';
 import '../base/common.dart';
 import '../base/file_system.dart';
 import '../base/logger.dart';
@@ -150,15 +149,13 @@ Future<String> _buildAotSnapshot(
   final String uiPath = fs.path.join(skyEnginePkg, 'lib', 'ui', 'ui.dart');
   final String vmServicePath = fs.path.join(skyEnginePkg, 'sdk_ext', 'vmservice_io.dart');
 
-  final List<String> inputPaths = <String>[
+  final List<String> filePaths = <String>[
     vmEntryPoints,
     ioEntryPoints,
     uiPath,
     vmServicePath,
   ];
 
-  final Set<String> outputPaths = new Set<String>();
-
   // These paths are used only on iOS.
   String snapshotDartIOS;
   String assembly;
@@ -167,15 +164,13 @@ Future<String> _buildAotSnapshot(
     case TargetPlatform.android_arm:
     case TargetPlatform.android_x64:
     case TargetPlatform.android_x86:
-      outputPaths.addAll(<String>[
-        vmSnapshotData,
-        isolateSnapshotData,
-      ]);
       break;
     case TargetPlatform.ios:
       snapshotDartIOS = artifacts.getArtifactPath(Artifact.snapshotDart, platform, buildMode);
       assembly = fs.path.join(outputDir.path, 'snapshot_assembly.S');
-      inputPaths.add(snapshotDartIOS);
+      filePaths.addAll(<String>[
+        snapshotDartIOS,
+      ]);
       break;
     case TargetPlatform.darwin_x64:
     case TargetPlatform.linux_x64:
@@ -184,9 +179,9 @@ Future<String> _buildAotSnapshot(
       assert(false);
   }
 
-  final Iterable<String> missingInputs = inputPaths.where((String p) => !fs.isFileSync(p));
-  if (missingInputs.isNotEmpty) {
-    printError('Missing input files: $missingInputs');
+  final List<String> missingFiles = filePaths.where((String p) => !fs.isFileSync(p)).toList();
+  if (missingFiles.isNotEmpty) {
+    printError('Missing files: $missingFiles');
     return null;
   }
   if (!processManager.canRun(genSnapshot)) {
@@ -212,17 +207,6 @@ Future<String> _buildAotSnapshot(
     genSnapshotCmd.add('--embedder_entry_points_manifest=$ioEntryPoints');
   }
 
-  // iOS symbols used to load snapshot data in the engine.
-  const String kVmSnapshotData = 'kDartVmSnapshotData';
-  const String kIsolateSnapshotData = 'kDartIsolateSnapshotData';
-
-  // iOS snapshot generated files, compiled object files.
-  final String kVmSnapshotDataC = fs.path.join(outputDir.path, '$kVmSnapshotData.c');
-  final String kIsolateSnapshotDataC = fs.path.join(outputDir.path, '$kIsolateSnapshotData.c');
-  final String kVmSnapshotDataO = fs.path.join(outputDir.path, '$kVmSnapshotData.o');
-  final String kIsolateSnapshotDataO = fs.path.join(outputDir.path, '$kIsolateSnapshotData.o');
-  final String assemblyO = fs.path.join(outputDir.path, 'snapshot_assembly.o');
-
   switch (platform) {
     case TargetPlatform.android_arm:
     case TargetPlatform.android_x64:
@@ -239,14 +223,9 @@ Future<String> _buildAotSnapshot(
       if (interpreter) {
         genSnapshotCmd.add('--snapshot_kind=core');
         genSnapshotCmd.add(snapshotDartIOS);
-        outputPaths.addAll(<String>[
-          kVmSnapshotDataO,
-          kIsolateSnapshotDataO,
-        ]);
       } else {
         genSnapshotCmd.add('--snapshot_kind=app-aot-assembly');
         genSnapshotCmd.add('--assembly=$assembly');
-        outputPaths.add(assemblyO);
       }
       break;
     case TargetPlatform.darwin_x64:
@@ -265,27 +244,6 @@ Future<String> _buildAotSnapshot(
 
   genSnapshotCmd.add(mainPath);
 
-  final File checksumFile = fs.file('$dependencies.checksum');
-  final List<File> checksumFiles = <File>[checksumFile, fs.file(dependencies)]
-      ..addAll(inputPaths.map(fs.file))
-      ..addAll(outputPaths.map(fs.file));
-  if (checksumFiles.every((File file) => file.existsSync())) {
-    try {
-      final String json = await checksumFile.readAsString();
-      final Checksum oldChecksum = new Checksum.fromJson(json);
-      final Set<String> snapshotInputPaths = await readDepfile(dependencies);
-      snapshotInputPaths.addAll(outputPaths);
-      final Checksum newChecksum = new Checksum.fromFiles(snapshotInputPaths);
-      if (oldChecksum == newChecksum) {
-        printTrace('Skipping AOT snapshot build. Checksums match.');
-        return outputPath;
-      }
-    } catch (e, s) {
-      // Log exception and continue, this step is a performance improvement only.
-      printTrace('Error during AOT snapshot checksum check: $e\n$s');
-    }
-  }
-
   final RunResult results = await runAsync(genSnapshotCmd);
   if (results.exitCode != 0) {
     printError('Dart snapshot generator failed with exit code ${results.exitCode}');
@@ -302,6 +260,16 @@ Future<String> _buildAotSnapshot(
   if (platform == TargetPlatform.ios) {
     printStatus('Building App.framework...');
 
+    // These names are known to from the engine.
+    const String kVmSnapshotData = 'kDartVmSnapshotData';
+    const String kIsolateSnapshotData = 'kDartIsolateSnapshotData';
+
+    final String kVmSnapshotDataC = fs.path.join(outputDir.path, '$kVmSnapshotData.c');
+    final String kIsolateSnapshotDataC = fs.path.join(outputDir.path, '$kIsolateSnapshotData.c');
+    final String kVmSnapshotDataO = fs.path.join(outputDir.path, '$kVmSnapshotData.o');
+    final String kIsolateSnapshotDataO = fs.path.join(outputDir.path, '$kIsolateSnapshotData.o');
+    final String assemblyO = fs.path.join(outputDir.path, 'snapshot_assembly.o');
+
     final List<String> commonBuildOptions = <String>['-arch', 'arm64', '-miphoneos-version-min=8.0'];
 
     if (interpreter) {
@@ -348,16 +316,5 @@ Future<String> _buildAotSnapshot(
     await runCheckedAsync(linkCommand);
   }
 
-  // Compute and record checksums.
-  try {
-    final Set<String> snapshotInputPaths = await readDepfile(dependencies);
-    snapshotInputPaths..addAll(outputPaths);
-    final Checksum checksum = new Checksum.fromFiles(snapshotInputPaths);
-    await checksumFile.writeAsString(checksum.toJson());
-  } catch (e, s) {
-    // Log exception and continue, this step is a performance improvement only.
-    printTrace('Error during AOT snapshot checksum output: $e\n$s');
-  }
-
   return outputPath;
 }

packages/flutter_tools/lib/src/flx.dart

@@ -65,7 +65,7 @@ Future<int> _createSnapshot({
     try {
         final String json = await checksumFile.readAsString();
         final Checksum oldChecksum = new Checksum.fromJson(json);
-        final Set<String> inputPaths = await readDepfile(depfilePath);
+        final Set<String> inputPaths = await _readDepfile(depfilePath);
         inputPaths.add(snapshotPath);
         final Checksum newChecksum = new Checksum.fromFiles(inputPaths);
         if (oldChecksum == newChecksum) {
@@ -85,7 +85,7 @@ Future<int> _createSnapshot({
 
   // Compute and record input file checksums.
   try {
-    final Set<String> inputPaths = await readDepfile(depfilePath);
+    final Set<String> inputPaths = await _readDepfile(depfilePath);
     inputPaths.add(snapshotPath);
     final Checksum checksum = new Checksum.fromFiles(inputPaths);
     await checksumFile.writeAsString(checksum.toJson());
@@ -96,6 +96,24 @@ Future<int> _createSnapshot({
   return 0;
 }
 
+/// Parses a VM snapshot dependency file.
+///
+/// Snapshot dependency files are a single line mapping the output snapshot to a
+/// space-separated list of input files used to generate that output. e.g,
+///
+/// outfile : file1.dart file2.dart file3.dart
+Future<Set<String>> _readDepfile(String depfilePath) async {
+  // Depfile format:
+  // outfile : file1.dart file2.dart file3.dart
+  final String contents = await fs.file(depfilePath).readAsString();
+  final String dependencies = contents.split(': ')[1];
+  return dependencies
+      .split(' ')
+      .map((String path) => path.trim())
+      .where((String path) => path.isNotEmpty)
+      .toSet();
+}
+
 Future<Null> build({
   String mainPath: defaultMainPath,
   String manifestPath: defaultManifestPath,

packages/flutter_tools/test/base/build_test.dart

@@ -64,43 +64,4 @@ void main() {
       });
     });
   });
-
-  group('readDepfile', () {
-    MemoryFileSystem fs;
-
-    setUp(() {
-      fs = new MemoryFileSystem();
-    });
-
-    testUsingContext('returns one file if only one is listed', () async {
-      await fs.file('a.d').writeAsString('snapshot.d: /foo/a.dart');
-      expect(await readDepfile('a.d'), unorderedEquals(<String>['/foo/a.dart']));
-    }, overrides: <Type, Generator>{ FileSystem: () => fs});
-
-    testUsingContext('returns multiple files', () async {
-      await fs.file('a.d').writeAsString('snapshot.d: /foo/a.dart /foo/b.dart');
-      expect(await readDepfile('a.d'), unorderedEquals(<String>[
-        '/foo/a.dart',
-        '/foo/b.dart',
-      ]));
-    }, overrides: <Type, Generator>{ FileSystem: () => fs});
-
-    testUsingContext('trims extra spaces between files', () async {
-      await fs.file('a.d').writeAsString('snapshot.d: /foo/a.dart    /foo/b.dart  /foo/c.dart');
-      expect(await readDepfile('a.d'), unorderedEquals(<String>[
-        '/foo/a.dart',
-        '/foo/b.dart',
-        '/foo/c.dart',
-      ]));
-    }, overrides: <Type, Generator>{ FileSystem: () => fs});
-
-    testUsingContext('returns files with spaces and backslashes', () async {
-      await fs.file('a.d').writeAsString(r'snapshot.d: /foo/a\ a.dart /foo/b\\b.dart /foo/c\\ c.dart');
-      expect(await readDepfile('a.d'), unorderedEquals(<String>[
-        r'/foo/a a.dart',
-        r'/foo/b\b.dart',
-        r'/foo/c\ c.dart',
-      ]));
-    }, overrides: <Type, Generator>{ FileSystem: () => fs});
-  });
 }