1 //===-- llvm/ADT/GraphTraits.h - Graph traits template ----------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 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. 12 // 13 // This file also defines the marker class Inverse that is used to iterate over 14 // graphs in a graph defined, inverse ordering... 15 // 16 //===----------------------------------------------------------------------===// 17 18 #ifndef LLVM_ADT_GRAPHTRAITS_H 19 #define LLVM_ADT_GRAPHTRAITS_H 20 21 namespace llvm { 22 23 // GraphTraits - This class should be specialized by different graph types... 24 // which is why the default version is empty. 25 // 26 template<class GraphType> 27 struct GraphTraits { 28 // Elements to provide: 29 30 // typedef NodeType - Type of Node in the graph 31 // typedef ChildIteratorType - Type used to iterate over children in graph 32 33 // static NodeType *getEntryNode(const GraphType &) 34 // Return the entry node of the graph 35 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. 40 // 41 42 43 // typedef ...iterator nodes_iterator; 44 // static nodes_iterator nodes_begin(GraphType *G) 45 // static nodes_iterator nodes_end (GraphType *G) 46 // 47 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph 48 49 50 // If anyone tries to use this class without having an appropriate 51 // specialization, make an error. If you get this error, it's because you 52 // need to include the appropriate specialization of GraphTraits<> for your 53 // graph, or you need to define it for a new graph type. Either that or 54 // your argument to XXX_begin(...) is unknown or needs to have the proper .h 55 // file #include'd. 56 // 57 typedef typename GraphType::UnknownGraphTypeError NodeType; 58 }; 59 60 61 // Inverse - This class is used as a little marker class to tell the graph 62 // iterator to iterate over the graph in a graph defined "Inverse" ordering. 63 // Not all graphs define an inverse ordering, and if they do, it depends on 64 // the graph exactly what that is. Here's an example of usage with the 65 // df_iterator: 66 // 67 // idf_iterator<Method*> I = idf_begin(M), E = idf_end(M); 68 // for (; I != E; ++I) { ... } 69 // 70 // Which is equivalent to: 71 // df_iterator<Inverse<Method*> > I = idf_begin(M), E = idf_end(M); 72 // for (; I != E; ++I) { ... } 73 // 74 template <class GraphType> 75 struct Inverse { 76 const GraphType &Graph; 77 78 inline Inverse(const GraphType &G) : Graph(G) {} 79 }; 80 81 // Provide a partial specialization of GraphTraits so that the inverse of an 82 // inverse falls back to the original graph. 83 template<class T> 84 struct GraphTraits<Inverse<Inverse<T> > > { 85 typedef typename GraphTraits<T>::NodeType NodeType; 86 typedef typename GraphTraits<T>::ChildIteratorType ChildIteratorType; 87 88 static NodeType *getEntryNode(Inverse<Inverse<T> > *G) { 89 return GraphTraits<T>::getEntryNode(G->Graph.Graph); 90 } 91 92 static ChildIteratorType child_begin(NodeType* N) { 93 return GraphTraits<T>::child_begin(N); 94 } 95 96 static ChildIteratorType child_end(NodeType* N) { 97 return GraphTraits<T>::child_end(N); 98 } 99 }; 100 101 } // End llvm namespace 102 103 #endif 104
