+//
+// 1. A Function* object, composed of BasicBlock nodes.
+// 2. An IntervalPartition& object, composed of Interval nodes.
+//
+// This iterator is defined to walk the control flow graph, returning intervals
+// in depth first order. These intervals are completely filled in except for
+// the predecessor fields (the successor information is filled in however).
+//
+// By default, the intervals created by this iterator are deleted after they
+// are no longer any use to the iterator. This behavior can be changed by
+// passing a false value into the intervals_begin() function. This causes the
+// IOwnMem member to be set, and the intervals to not be deleted.
+//
+// It is only safe to use this if all of the intervals are deleted by the caller
+// and all of the intervals are processed. However, the user of the iterator is
+// not allowed to modify or delete the intervals until after the iterator has
+// been used completely. The IntervalPartition class uses this functionality.