+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file builds on the ADT/GraphTraits.h file to build generic depth
+// first graph iterator. This file exposes the following functions/types:
+//
+// df_begin/df_end/df_iterator
+// * Normal depth-first iteration - visit a node and then all of its children.
+//
+// idf_begin/idf_end/idf_iterator
+// * Depth-first iteration on the 'inverse' graph.
+//
+// df_ext_begin/df_ext_end/df_ext_iterator
+// * Normal depth-first iteration - visit a node and then all of its children.
+// This iterator stores the 'visited' set in an external set, which allows
+// it to be more efficient, and allows external clients to use the set for
+// other purposes.
+//
+// idf_ext_begin/idf_ext_end/idf_ext_iterator
+// * Depth-first iteration on the 'inverse' graph.
+// This iterator stores the 'visited' set in an external set, which allows
+// it to be more efficient, and allows external clients to use the set for
+// other purposes.