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 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph 47 48 // static unsigned size (GraphType *G) 49 // Return total number of nodes in the graph 50 // 51 52 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 58 // file #include'd. 59 // 60 typedef typename GraphType::UnknownGraphTypeError NodeType; 61 }; 62 63 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 68 // df_iterator: 69 // 70 // idf_iterator<Method*> I = idf_begin(M), E = idf_end(M); 71 // for (; I != E; ++I) { ... } 72 // 73 // Which is equivalent to: 74 // df_iterator<Inverse<Method*> > I = idf_begin(M), E = idf_end(M); 75 // for (; I != E; ++I) { ... } 76 // 77 template <class GraphType> 78 struct Inverse { 79 const GraphType &Graph; 80 InverseInverse81 inline Inverse(const GraphType &G) : Graph(G) {} 82 }; 83 84 // Provide a partial specialization of GraphTraits so that the inverse of an 85 // inverse falls back to the original graph. 86 template<class T> 87 struct GraphTraits<Inverse<Inverse<T> > > { 88 typedef typename GraphTraits<T>::NodeType NodeType; 89 typedef typename GraphTraits<T>::ChildIteratorType ChildIteratorType; 90 91 static NodeType *getEntryNode(Inverse<Inverse<T> > *G) { 92 return GraphTraits<T>::getEntryNode(G->Graph.Graph); 93 } 94 95 static ChildIteratorType child_begin(NodeType* N) { 96 return GraphTraits<T>::child_begin(N); 97 } 98 99 static ChildIteratorType child_end(NodeType* N) { 100 return GraphTraits<T>::child_end(N); 101 } 102 }; 103 104 } // End llvm namespace 105 106 #endif 107