Create entrypoint to measure performance of the dart2js frontend

pkg/compiler/tool/perf.dart

Index: pkg/compiler/tool/perf.dart
diff --git a/pkg/compiler/tool/perf.dart b/pkg/compiler/tool/perf.dart
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+// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// An entrypoint used to run portions of dart2js and measure its performance.
+library compiler.tool.perf;
+
+import 'dart:async';
+import 'dart:io';
+
+import 'package:compiler/compiler_new.dart';
+import 'package:compiler/src/common.dart';
+import 'package:compiler/src/diagnostics/diagnostic_listener.dart';
+import 'package:compiler/src/diagnostics/messages.dart'
+    show Message, MessageTemplate;
+import 'package:compiler/src/io/source_file.dart';
+import 'package:compiler/src/options.dart' show ParserOptions;
+import 'package:compiler/src/options.dart';
+import 'package:compiler/src/parser/element_listener.dart' show ScannerOptions;
+import 'package:compiler/src/parser/listener.dart';
+import 'package:compiler/src/parser/node_listener.dart' show NodeListener;
+import 'package:compiler/src/parser/parser.dart' show Parser;
+import 'package:compiler/src/parser/partial_parser.dart';
+import 'package:compiler/src/platform_configuration.dart' as platform;
+import 'package:compiler/src/scanner/scanner.dart';
+import 'package:compiler/src/source_file_provider.dart';
+import 'package:compiler/src/tokens/token.dart' show Token;
+import 'package:package_config/discovery.dart' show findPackages;
+import 'package:package_config/packages.dart' show Packages;
+import 'package:package_config/src/util.dart' show checkValidPackageUri;
+
+/// Cumulative total number of chars scanned.
+int scanTotalChars = 0;
+
+/// Cumulative time spent scanning.
+Stopwatch scanTimer = new Stopwatch();
+
+/// Helper class used to load source files using dart2js's internal APIs.
+_Loader loader;
+
+main(List<String> args) async {
+  // TODO(sigmund): provide sdk folder as well.
+  if (args.length < 2) {
+    print('usage: perf.dart <bench-id> <entry.dart>');
+    exit(1);
+  }
+  var totalTimer = new Stopwatch()..start();
+
+  var bench = args[0];
+  var entryUri = Uri.base.resolve(args[1]);
+
+  await setup(entryUri);
+
+  if (bench == 'scan') {
+    Set<SourceFile> files = await scanReachableFiles(entryUri);
+    // TODO(sigmund): consider replacing the warmup with instrumented snapshots.
+    for (int i = 0; i < 10; i++) scanFiles(files);
+  } else if (bench == 'parse') {
+    Set<SourceFile> files = await scanReachableFiles(entryUri);
+    // TODO(sigmund): consider replacing the warmup with instrumented snapshots.
+    for (int i = 0; i < 10; i++) parseFiles(files);
+  } else {
+    print('unsupported bench-id: $bench. Please specify "scan" or "parse"');
+    // TODO(sigmund): implement the remaining benchmarks.
+    exit(1);
+  }
+
+  totalTimer.stop();
+  report("total", totalTimer.elapsedMicroseconds);
+}
+
+Future setup(Uri entryUri) async {
+  var inputProvider = new CompilerSourceFileProvider();
+  var sdkLibraries = await platform.load(_platformConfigUri, inputProvider);
+  var packages = await findPackages(entryUri);
+  loader = new _Loader(inputProvider, sdkLibraries, packages);
+}
+
+/// Load and scans all files we need to process: files reachable from the
+/// entrypoint and all core libraries automatically included by the VM.
+Future<Set<SourceFile>> scanReachableFiles(Uri entryUri) async {
+  var files = new Set<SourceFile>();
+  var loadTimer = new Stopwatch()..start();
+  var entrypoints = [
+    entryUri,
+    Uri.parse("dart:async"),
+    Uri.parse("dart:collection"),
+    Uri.parse("dart:convert"),
+    Uri.parse("dart:core"),
+    Uri.parse("dart:developer"),
+    Uri.parse("dart:_internal"),
+    Uri.parse("dart:io"),
+    Uri.parse("dart:isolate"),
+    Uri.parse("dart:math"),
+    Uri.parse("dart:mirrors"),
+    Uri.parse("dart:typed_data"),
+  ];
+  for (var entry in entrypoints) {
+    await collectSources(await loader.loadFile(entry), files);
+  }
+  loadTimer.stop();
+
+  print('input size: ${scanTotalChars} chars');
+  var loadTime = loadTimer.elapsedMicroseconds - scanTimer.elapsedMicroseconds;
+  report("load", loadTime);
+  report("scan", scanTimer.elapsedMicroseconds);
+  return files;
+}
+
+/// Scans every file in [files] and reports the time spent doing so.
+void scanFiles(Set<SourceFile> files) {
+  // The code below will record again how many chars are scanned and how long it
+  // takes to scan them, even though we already did so in [scanReachableFiles].
+  // Recording and reporting this twice is unnecessary, but we do so for now to
+  // validate that the results are consistent.
+  scanTimer = new Stopwatch();
+  var old = scanTotalChars;
+  scanTotalChars = 0;
+  for (var source in files) {
+    tokenize(source);
+  }
+
+  // Report size and scanning time again. See discussion above.
+  if (old != scanTotalChars) print('input size changed? ${old} chars');
+  report("scan", scanTimer.elapsedMicroseconds);
+}
+
+/// Parses every file in [files] and reports the time spent doing so.
+void parseFiles(Set<SourceFile> files) {
+  // The code below will record again how many chars are scanned and how long it
+  // takes to scan them, even though we already did so in [scanReachableFiles].
+  // Recording and reporting this twice is unnecessary, but we do so for now to
+  // validate that the results are consistent.
+  scanTimer = new Stopwatch();
+  var old = scanTotalChars;
+  scanTotalChars = 0;
+  var parseTimer = new Stopwatch()..start();
+  for (var source in files) {
+    parseFull(source);
+  }
+  parseTimer.stop();
+
+  // Report size and scanning time again. See discussion above.
+  if (old != scanTotalChars) print('input size changed? ${old} chars');
+  report("scan", scanTimer.elapsedMicroseconds);
+
+  report(
+      "parse", parseTimer.elapsedMicroseconds - scanTimer.elapsedMicroseconds);
+}
+
+/// Add to [files] all sources reachable from [start].
+Future collectSources(SourceFile start, Set<SourceFile> files) async {
+  if (!files.add(start)) return;
+  for (var directive in parseDirectives(start)) {
+    var next = await loader.loadFile(start.uri.resolve(directive));
+    await collectSources(next, files);
+  }
+}
+
+/// Uses the diet-parser to parse only directives in [source], returns the
+/// URIs seen in import/export/part directives in the file.
+Set<String> parseDirectives(SourceFile source) {
+  var tokens = tokenize(source);
+  var listener = new DirectiveListener();
+  new PartialParser(listener, const _ParserOptions()).parseUnit(tokens);
+  return listener.targets;
+}
+
+/// Parse the full body of [source].
+parseFull(SourceFile source) {
+  var tokens = tokenize(source);
+  NodeListener listener = new NodeListener(
+      const ScannerOptions(canUseNative: true), new FakeReporter(), null);
+  Parser parser = new Parser(listener, const _ParserOptions());
+  parser.parseUnit(tokens);
+  return listener.popNode();
+}
+
+/// Scan [source] and return the first token produced by the scanner.
+Token tokenize(SourceFile source) {
+  scanTimer.start();
+  scanTotalChars += source.length;
+  var token = new Scanner(source).tokenize();
+  scanTimer.stop();
+  return token;
+}
+
+/// Report that metric [name] took [time] micro-seconds to process
+/// [scanTotalChars] characters.
+void report(String name, int time) {
+  var sb = new StringBuffer();
+  sb.write('$name: $time us, ${time ~/ 1000} ms');
+  sb.write(', ${scanTotalChars * 1000 ~/ time} chars/ms');
+  print('$sb');
+}
+
+/// Listener that parses out just the uri in imports, exports, and part
+/// directives.
+class DirectiveListener extends Listener {
+  Set<String> targets = new Set<String>();
+
+  bool inDirective = false;
+  void enterDirective() {
+    inDirective = true;
+  }
+
+  void exitDirective() {
+    inDirective = false;
+  }
+
+  void beginImport(Token importKeyword) => enterDirective();
+  void beginExport(Token token) => enterDirective();
+  void beginPart(Token token) => enterDirective();
+
+  void beginLiteralString(Token token) {
+    if (inDirective) {
+      var quotedString = token.value;
+      targets.add(quotedString.substring(1, quotedString.length - 1));
+    }
+  }
+
+  void endExport(Token exportKeyword, Token semicolon) => exitDirective();
+  void endImport(Token importKeyword, Token deferredKeyword, Token asKeyword,
+          Token semicolon) =>
+      exitDirective();
+  void endPart(Token partKeyword, Token semicolon) => exitDirective();
+}
+
+Uri _libraryRoot = Platform.script.resolve('../../../sdk/');
+Uri _platformConfigUri = _libraryRoot.resolve("lib/dart_server.platform");
+
+class FakeReporter extends DiagnosticReporter {
+  final hasReportedError = false;
+  final options = new FakeReporterOptions();
+
+  withCurrentElement(e, f) => f();
+  log(m) => print(m);
+  internalError(_, m) => print(m);
+  spanFromSpannable(_) => null;
+
+  void reportError(DiagnosticMessage message,
+      [List<DiagnosticMessage> infos = const <DiagnosticMessage>[]]) {
+    print('error: ${message.message}');
+  }
+
+  void reportWarning(DiagnosticMessage message,
+      [List<DiagnosticMessage> infos = const <DiagnosticMessage>[]]) {
+    print('warning: ${message.message}');
+  }
+
+  void reportHint(DiagnosticMessage message,
+      [List<DiagnosticMessage> infos = const <DiagnosticMessage>[]]) {
+    print('hint: ${message.message}');
+  }
+
+  void reportInfo(_, __, [Map arguments = const {}]) {}
+
+  DiagnosticMessage createMessage(_, MessageKind kind,
+      [Map arguments = const {}]) {
+    MessageTemplate template = MessageTemplate.TEMPLATES[kind];
+    Message message = template.message(arguments, false);
+    return new DiagnosticMessage(null, null, message);
+  }
+}
+
+class FakeReporterOptions {
+  bool get suppressHints => false;
+  bool get hidePackageWarnings => false;
+}
+
+class _Loader {
+  CompilerInput inputProvider;
+
+  /// Maps dart-URIs to a known location in the sdk.
+  Map<String, Uri> sdkLibraries;
+  Map<Uri, SourceFile> _cache = {};
+  Packages packages;
+
+  _Loader(this.inputProvider, this.sdkLibraries, this.packages);
+
+  Future<SourceFile> loadFile(Uri uri) async {
+    if (!uri.isAbsolute) throw 'Relative uri $uri provided to readScript.';
+    Uri resourceUri = _translateUri(uri);
+    if (resourceUri == null || resourceUri.scheme == 'dart-ext') {
+      throw '$uri not resolved or unsupported.';
+    }
+    var file = _cache[resourceUri];
+    if (file != null) return _cache[resourceUri];
+    return _cache[resourceUri] = await _readFile(resourceUri);
+  }
+
+  Future<SourceFile> _readFile(Uri uri) async {
+    var data = await inputProvider.readFromUri(uri);
+    if (data is List<int>) return new Utf8BytesSourceFile(uri, data);
+    if (data is String) return new StringSourceFile.fromUri(uri, data);
+    // TODO(sigmund): properly handle errors, just report, return null, wrap
+    // above and continue...
+    throw "Expected a 'String' or a 'List<int>' from the input "
+        "provider, but got: ${data.runtimeType}.";
+  }
+
+  Uri _translateUri(Uri uri) {
+    if (uri.scheme == 'dart') return sdkLibraries[uri.path];
+    if (uri.scheme == 'package') return _translatePackageUri(uri);
+    return uri;
+  }
+
+  Uri _translatePackageUri(Uri uri) {
+    checkValidPackageUri(uri);
+    return packages.resolve(uri, notFound: (_) {
+      print('$uri not found');
+    });
+  }
+}
+
+class _ParserOptions implements ParserOptions {
+  const _ParserOptions();
+  bool get enableGenericMethodSyntax => true;
+}