Generated source mapping through CPS.

pkg/compiler/lib/src/helpers/helpers.dart

Index: pkg/compiler/lib/src/helpers/helpers.dart
diff --git a/pkg/compiler/lib/src/helpers/helpers.dart b/pkg/compiler/lib/src/helpers/helpers.dart
index bcfa12c9b5ff6b0d3ce3f92cb1f66d4ddd3bbc8d..9f7e2848fe6aab78a3b36e62fb9aa52c9d37f32e 100644
--- a/pkg/compiler/lib/src/helpers/helpers.dart
+++ b/pkg/compiler/lib/src/helpers/helpers.dart
@@ -93,3 +93,52 @@ _reportHere(Compiler compiler, Spannable node, String debugMessage) {
   compiler.reportInfo(node,
       MessageKind.GENERIC, {'text': 'HERE: $debugMessage'});
 }
+
+/// Set of tracked objects used by [track] and [ifTracked].
+var _trackedObjects = new Set();
+
+/// Global default value for the `printTrace` option of [track] and [ifTracked].
+bool trackWithTrace = false;
+
+/// If [doTrack] is `true`, add [object] to the set of tracked objects.
+///
+/// If tracked, [message] is printed along the hash code and toString of
+/// [object]. If [printTrace] is `true` a trace printed additionally.
+/// If [printTrace] is `null`, [trackWithTrace] determines whether a trace is
+/// printed.
+///
+/// [object] is returned as the result of the method.
+track(bool doTrack, Object object, String message, {bool printTrace}) {
+  if (!doTrack) return object;
+  _trackedObjects.add(object);
+  String msg = 'track: ${object.hashCode}:$object:$message';
+  if (printTrace == null) printTrace = trackWithTrace;
+  if (printTrace) {
+    trace(msg);
+  } else {
+    debugPrint(msg);
+  }
+  return object;
+}
+
+/// Returns `true` if [object] is in the set of tracked objects.
+///
+/// If [message] is provided it is printed along the hash code and toString of
+/// [object]. If [printTrace] is `true` a trace printed additionally. If
+/// [printTrace] is `null`, [trackWithTrace] determines whether a trace is
+/// printed.
+bool ifTracked(Object object, {String message, bool printTrace}) {
+  if (_trackedObjects.contains(object)) {
+    if (message != null) {
+      String msg = 'tracked: ${object.hashCode}:$object:$message';
+      if (printTrace == null) printTrace = trackWithTrace;
+      if (printTrace) {
+        trace(msg);
+      } else {
+        debugPrint(msg);
+      }
+    }
+    return true;
+  }
+  return false;
+}