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 #include "llvm/ADT/iterator_range.h" 22 23 namespace llvm { 24 25 // GraphTraits - This class should be specialized by different graph types... 26 // which is why the default version is empty. 27 // 28 template<class GraphType> 29 struct GraphTraits { 30 // Elements to provide: 31 32 // typedef NodeRef - Type of Node token in the graph, which should 33 // be cheap to copy. 34 // typedef ChildIteratorType - Type used to iterate over children in graph, 35 // dereference to a NodeRef. 36 37 // static NodeRef getEntryNode(const GraphType &) 38 // Return the entry node of the graph 39 40 // static ChildIteratorType child_begin(NodeRef) 41 // static ChildIteratorType child_end (NodeRef) 42 // Return iterators that point to the beginning and ending of the child 43 // node list for the specified node. 44 45 // typedef ...iterator nodes_iterator; - dereference to a NodeRef 46 // static nodes_iterator nodes_begin(GraphType *G) 47 // static nodes_iterator nodes_end (GraphType *G) 48 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph 49 50 // typedef EdgeRef - Type of Edge token in the graph, which should 51 // be cheap to copy. 52 // typedef ChildEdgeIteratorType - Type used to iterate over children edges in 53 // graph, dereference to a EdgeRef. 54 55 // static ChildEdgeIteratorType child_edge_begin(NodeRef) 56 // static ChildEdgeIteratorType child_edge_end(NodeRef) 57 // Return iterators that point to the beginning and ending of the 58 // edge list for the given callgraph node. 59 // 60 // static NodeRef edge_dest(EdgeRef) 61 // Return the destination node of an edge. 62 63 // static unsigned size (GraphType *G) 64 // Return total number of nodes in the graph 65 66 // If anyone tries to use this class without having an appropriate 67 // specialization, make an error. If you get this error, it's because you 68 // need to include the appropriate specialization of GraphTraits<> for your 69 // graph, or you need to define it for a new graph type. Either that or 70 // your argument to XXX_begin(...) is unknown or needs to have the proper .h 71 // file #include'd. 72 using NodeRef = typename GraphType::UnknownGraphTypeError; 73 }; 74 75 // Inverse - This class is used as a little marker class to tell the graph 76 // iterator to iterate over the graph in a graph defined "Inverse" ordering. 77 // Not all graphs define an inverse ordering, and if they do, it depends on 78 // the graph exactly what that is. Here's an example of usage with the 79 // df_iterator: 80 // 81 // idf_iterator<Method*> I = idf_begin(M), E = idf_end(M); 82 // for (; I != E; ++I) { ... } 83 // 84 // Which is equivalent to: 85 // df_iterator<Inverse<Method*>> I = idf_begin(M), E = idf_end(M); 86 // for (; I != E; ++I) { ... } 87 // 88 template <class GraphType> 89 struct Inverse { 90 const GraphType &Graph; 91 92 inline Inverse(const GraphType &G) : Graph(G) {} 93 }; 94 95 // Provide a partial specialization of GraphTraits so that the inverse of an 96 // inverse falls back to the original graph. 97 template <class T> struct GraphTraits<Inverse<Inverse<T>>> : GraphTraits<T> {}; 98 99 // Provide iterator ranges for the graph traits nodes and children 100 template <class GraphType> 101 iterator_range<typename GraphTraits<GraphType>::nodes_iterator> 102 nodes(const GraphType &G) { 103 return make_range(GraphTraits<GraphType>::nodes_begin(G), 104 GraphTraits<GraphType>::nodes_end(G)); 105 } 106 template <class GraphType> 107 iterator_range<typename GraphTraits<Inverse<GraphType>>::nodes_iterator> 108 inverse_nodes(const GraphType &G) { 109 return make_range(GraphTraits<Inverse<GraphType>>::nodes_begin(G), 110 GraphTraits<Inverse<GraphType>>::nodes_end(G)); 111 } 112 113 template <class GraphType> 114 iterator_range<typename GraphTraits<GraphType>::ChildIteratorType> 115 children(const typename GraphTraits<GraphType>::NodeRef &G) { 116 return make_range(GraphTraits<GraphType>::child_begin(G), 117 GraphTraits<GraphType>::child_end(G)); 118 } 119 120 template <class GraphType> 121 iterator_range<typename GraphTraits<Inverse<GraphType>>::ChildIteratorType> 122 inverse_children(const typename GraphTraits<GraphType>::NodeRef &G) { 123 return make_range(GraphTraits<Inverse<GraphType>>::child_begin(G), 124 GraphTraits<Inverse<GraphType>>::child_end(G)); 125 } 126 127 template <class GraphType> 128 iterator_range<typename GraphTraits<GraphType>::ChildEdgeIteratorType> 129 children_edges(const typename GraphTraits<GraphType>::NodeRef &G) { 130 return make_range(GraphTraits<GraphType>::child_edge_begin(G), 131 GraphTraits<GraphType>::child_edge_end(G)); 132 } 133 134 } // end namespace llvm 135 136 #endif // LLVM_ADT_GRAPHTRAITS_H 137