Move dart2js from sdk/lib/_internal/compiler to pkg/compiler

sdk/lib/_internal/compiler/implementation/helpers/track_map.dart

-// Copyright (c) 2014, 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.
-
-part of dart2js.helpers;
-
-/**
- * The track map is a simple wrapper around a map that keeps track
- * of the 'final' size of maps grouped by description. It allows
- * determining the distribution of sizes for a specific allocation
- * site and it can be used like this:
- *
- *    Map<String, int> map = new TrackMap<String, int>("my-map");
- *
- * After finishing the compilaton, the histogram of track map sizes
- * is printed but only when running in verbose mode.
- */
-class TrackMap<K, V> implements Map<K, V> {
-  final Map _map;
-  final List _counts;
-  static final Map<String, List<int>> _countsMap = {};
-
-  TrackMap._internal(this._counts) : _map = new Map<K, V>();
-
-  factory TrackMap(String description) {
-    List counts = _countsMap.putIfAbsent(description, () => [ 0 ]);
-    Map result = new TrackMap<K, V>._internal(counts);
-    counts[0]++;
-    return result;
-  }
-
-  static void printHistogram() {
-    _countsMap.forEach((description, counts) {
-      print('$description -- ${counts.length} maps');
-
-      // Count the total number of maps.
-      int sum = 0;
-      for (int i = 0; i < counts.length; i++) {
-        sum += counts[i];
-      }
-      int increment = sum ~/ 10;
-      int target = increment;
-      int accumulated = 0;
-      for (int i = 0; i < counts.length; i++) {
-        accumulated += counts[i];
-        if (accumulated >= target) {
-          String percent = (accumulated / sum * 100).toStringAsFixed(1);
-          print('  -- $percent%: length <= $i');
-          target += increment;
-        }
-      }
-    });
-  }
-
-  int get length => _map.length;
-  bool get isEmpty => _map.isEmpty;
-  bool get isNotEmpty => _map.isNotEmpty;
-
-  Iterable<K> get keys => _map.keys;
-  Iterable<V> get values => _map.values;
-
-  bool containsKey(K key) => _map.containsKey(key);
-  bool containsValue(V value) => _map.containsValue(value);
-
-  V operator[](K key) => _map[key];
-  String toString() => _map.toString();
-
-  void forEach(void action(K key, V value)) {
-    _map.forEach(action);
-  }
-
-  void operator[]=(K key, V value) {
-    if (!_map.containsKey(key)) {
-      _notifyLengthChanged(1);
-      _map[key] = value;
-    }
-  }
-
-  V putIfAbsent(K key, V ifAbsent()) {
-    if (containsKey(key)) return this[key];
-    V value = ifAbsent();
-    this[key] = value;
-    return value;
-  }
-
-  V remove(Object key) {
-    if (_map.containsKey(key)) {
-      _notifyLengthChanged(-1);
-    }
-    return _map.remove(key);
-  }
-
-  void addAll(Map<K, V> other) {
-    other.forEach((key, value) => this[key] = value);
-  }
-
-  void clear() {
-    _notifyLengthChanged(-_map.length);
-    _map.clear();
-  }
-
-  void _notifyLengthChanged(int delta) {
-    int oldLength = _map.length;
-    int newLength = oldLength + delta;
-    _counts[oldLength]--;
-    if (newLength < _counts.length) {
-      _counts[newLength]++;
-    } else {
-      _counts.add(1);
-      assert(newLength == _counts.length - 1);
-    }
-  }
-}