1 //===-- Support/GraphTraits.h - Graph traits template -----------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the little GraphTraits<X> template class that should be
11 // specialized by classes that want to be iteratable by generic graph iterators.
13 // This file also defines the marker class Inverse that is used to iterate over
14 // graphs in a graph defined, inverse ordering...
16 //===----------------------------------------------------------------------===//
18 #ifndef SUPPORT_GRAPHTRAITS_H
19 #define SUPPORT_GRAPHTRAITS_H
21 // GraphTraits - This class should be specialized by different graph types...
22 // which is why the default version is empty.
24 template<class GraphType>
26 // Elements to provide:
28 // typedef NodeType - Type of Node in the graph
29 // typedef ChildIteratorType - Type used to iterate over children in graph
31 // static NodeType *getEntryNode(GraphType *)
32 // Return the entry node of the graph
34 // static ChildIteratorType child_begin(NodeType *)
35 // static ChildIteratorType child_end (NodeType *)
36 // Return iterators that point to the beginning and ending of the child
37 // node list for the specified node.
41 // typedef ...iterator nodes_iterator;
42 // static nodes_iterator nodes_begin(GraphType *G)
43 // static nodes_iterator nodes_end (GraphType *G)
45 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
48 // If anyone tries to use this class without having an appropriate
49 // specialization, make an error. If you get this error, it's because you
50 // need to include the appropriate specialization of GraphTraits<> for your
51 // graph, or you need to define it for a new graph type. Either that or
52 // your argument to XXX_begin(...) is unknown or needs to have the proper .h
55 typedef typename GraphType::UnknownGraphTypeError NodeType;
59 // Inverse - This class is used as a little marker class to tell the graph
60 // iterator to iterate over the graph in a graph defined "Inverse" ordering.
61 // Not all graphs define an inverse ordering, and if they do, it depends on
62 // the graph exactly what that is. Here's an example of usage with the
65 // idf_iterator<Method*> I = idf_begin(M), E = idf_end(M);
66 // for (; I != E; ++I) { ... }
68 // Which is equivalent to:
69 // df_iterator<Inverse<Method*> > I = idf_begin(M), E = idf_end(M);
70 // for (; I != E; ++I) { ... }
72 template <class GraphType>
76 inline Inverse(GraphType &G) : Graph(G) {}