Collate stacks in test output

pkg/compiler/tool/status_files/stacks.dart

+// Copyright (c) 2017, 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.
+
+// $ dart stacks.dart LOG > STACK.txt

[Siggi Cherem (dart-lang), 2017/08/09 18:09:06]

consider renaming to include a verb that indicates what the script does? for
example:
  rank_stacks.dart
  show_top_stacks.dart
?

[sra1, 2017/08/09 20:15:13]

Done.

+
+import 'dart:io';
+
+import 'log_parser.dart';
+
+const STACK_PRINT_LENGTH = 12;
+const HOW_MANY_STACKS = 30;
+
+main(args) {
+  String text;
+
+  for (String arg in args) {
+    // Parse options.
+
+    if (text == null) {
+      var uri = Uri.base.resolve(arg);
+      var file = new File.fromUri(uri);
+      if (!file.existsSync()) {
+        print('file not found: $file');
+        exit(1);
+      }
+      text = file.readAsStringSync();
+    } else {
+      print('Extra file argument "$arg"');
+      exit(1);
+    }
+  }
+
+  if (text == null) {
+    print('No input file');
+    exit(1);
+  }
+
+  var records = parse(text);
+  var trie = new TrieNode(null);
+  for (var record in records) {
+    enter(record, 0, trie);
+  }
+
+  var leaves = trieLeaves(trie).toList();
+  leaves.sort((a, b) => b.length.compareTo(a.length));
+  for (var leaf in leaves.take(HOW_MANY_STACKS)) {
+    print('');
+    var examples = leaf.members.map((r) => r.fullReason).toSet();
+    print('${leaf.length} of:');
+    for (var example in examples) {
+      example = '\t' + example.replaceAll('\n', '\n\t');
+      print('     .${example}');
+    }
+
+    for (var line in leaf.members.first.stack.take(STACK_PRINT_LENGTH)) {
+      print('  $line');
+    }
+  }
+}
+
+class TrieNode {
+  final int depth;
+  final String key;
+  final map = {};

[Siggi Cherem (dart-lang), 2017/08/09 18:08:02]

Map<String, TrieNode> ?

[sra1, 2017/08/09 20:15:13]

Done.

+  final List<Record> members = <Record>[];
+
+  int get length => members.length;
+
+  TrieNode(this.key, [this.depth = 0]);
+
+  String toString() => 'TrieNode(#$length)';
+}
+
+void enter(Record record, int depth, TrieNode root) {
+  root.members.add(record);
+  if (depth >= record.stack.length) return;
+  var key = record.stack[depth];
+  var node = root.map[key] ??= new TrieNode(key, depth + 1);
+  enter(record, depth + 1, node);
+}
+
+void printTrie(TrieNode node) {
+  var indent = '  ' * node.depth;
+  print('${indent} ${node.length} ${node.key}');
+  for (var key in node.map.keys) {
+    printTrie(node.map[key]);
+  }
+}
+
+trieLeaves(node) sync* {
+  if (node.map.isEmpty) {
+    yield node;
+  } else {
+    for (var v in node.map.values) {
+      yield* trieLeaves(v);
+    }
+  }
+}