1 //===-- llvm/ADT/GraphTraits.h - Graph traits template ----------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // 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 LLVM_ADT_GRAPHTRAITS_H
19 #define LLVM_ADT_GRAPHTRAITS_H
23 // GraphTraits - This class should be specialized by different graph types...
24 // which is why the default version is empty.
26 template<class GraphType>
28 // Elements to provide:
30 // typedef NodeType - Type of Node in the graph
31 // typedef ChildIteratorType - Type used to iterate over children in graph
33 // static NodeType *getEntryNode(const GraphType &)
34 // Return the entry node of the graph
36 // static ChildIteratorType child_begin(NodeType *)
37 // static ChildIteratorType child_end (NodeType *)
38 // Return iterators that point to the beginning and ending of the child
39 // node list for the specified node.
43 // typedef ...iterator nodes_iterator;
44 // static nodes_iterator nodes_begin(GraphType *G)
45 // static nodes_iterator nodes_end (GraphType *G)
46 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
48 // static unsigned size (GraphType *G)
49 // Return total number of nodes in the graph
53 // If anyone tries to use this class without having an appropriate
54 // specialization, make an error. If you get this error, it's because you
55 // need to include the appropriate specialization of GraphTraits<> for your
56 // graph, or you need to define it for a new graph type. Either that or
57 // your argument to XXX_begin(...) is unknown or needs to have the proper .h
60 typedef typename GraphType::UnknownGraphTypeError NodeType;
64 // Inverse - This class is used as a little marker class to tell the graph
65 // iterator to iterate over the graph in a graph defined "Inverse" ordering.
66 // Not all graphs define an inverse ordering, and if they do, it depends on
67 // the graph exactly what that is. Here's an example of usage with the
70 // idf_iterator<Method*> I = idf_begin(M), E = idf_end(M);
71 // for (; I != E; ++I) { ... }
73 // Which is equivalent to:
74 // df_iterator<Inverse<Method*> > I = idf_begin(M), E = idf_end(M);
75 // for (; I != E; ++I) { ... }
77 template <class GraphType>
79 const GraphType &Graph;
81 inline Inverse(const GraphType &G) : Graph(G) {}
84 // Provide a partial specialization of GraphTraits so that the inverse of an
85 // inverse falls back to the original graph.
87 struct GraphTraits<Inverse<Inverse<T> > > {
88 typedef typename GraphTraits<T>::NodeType NodeType;
89 typedef typename GraphTraits<T>::ChildIteratorType ChildIteratorType;
91 static NodeType *getEntryNode(Inverse<Inverse<T> > *G) {
92 return GraphTraits<T>::getEntryNode(G->Graph.Graph);
95 static ChildIteratorType child_begin(NodeType* N) {
96 return GraphTraits<T>::child_begin(N);
99 static ChildIteratorType child_end(NodeType* N) {
100 return GraphTraits<T>::child_end(N);
104 } // End llvm namespace