CFG.h revision 202375
1//===-- llvm/Support/CFG.h - Process LLVM structures as graphs --*- 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 specializations of GraphTraits that allow Function and 11// BasicBlock graphs to be treated as proper graphs for generic algorithms. 12// 13//===----------------------------------------------------------------------===// 14 15#ifndef LLVM_SUPPORT_CFG_H 16#define LLVM_SUPPORT_CFG_H 17 18#include "llvm/ADT/GraphTraits.h" 19#include "llvm/Function.h" 20#include "llvm/InstrTypes.h" 21 22namespace llvm { 23 24//===----------------------------------------------------------------------===// 25// BasicBlock pred_iterator definition 26//===----------------------------------------------------------------------===// 27 28template <class _Ptr, class _USE_iterator> // Predecessor Iterator 29class PredIterator : public std::iterator<std::forward_iterator_tag, 30 _Ptr, ptrdiff_t> { 31 typedef std::iterator<std::forward_iterator_tag, _Ptr, ptrdiff_t> super; 32 _USE_iterator It; 33public: 34 typedef PredIterator<_Ptr,_USE_iterator> _Self; 35 typedef typename super::pointer pointer; 36 37 inline void advancePastNonTerminators() { 38 // Loop to ignore non terminator uses (for example PHI nodes)... 39 while (!It.atEnd() && !isa<TerminatorInst>(*It)) 40 ++It; 41 } 42 43 inline PredIterator(_Ptr *bb) : It(bb->use_begin()) { 44 advancePastNonTerminators(); 45 } 46 inline PredIterator(_Ptr *bb, bool) : It(bb->use_end()) {} 47 48 inline bool operator==(const _Self& x) const { return It == x.It; } 49 inline bool operator!=(const _Self& x) const { return !operator==(x); } 50 51 inline pointer operator*() const { 52 assert(!It.atEnd() && "pred_iterator out of range!"); 53 return cast<TerminatorInst>(*It)->getParent(); 54 } 55 inline pointer *operator->() const { return &(operator*()); } 56 57 inline _Self& operator++() { // Preincrement 58 assert(!It.atEnd() && "pred_iterator out of range!"); 59 ++It; advancePastNonTerminators(); 60 return *this; 61 } 62 63 inline _Self operator++(int) { // Postincrement 64 _Self tmp = *this; ++*this; return tmp; 65 } 66}; 67 68typedef PredIterator<BasicBlock, Value::use_iterator> pred_iterator; 69typedef PredIterator<const BasicBlock, 70 Value::use_const_iterator> pred_const_iterator; 71 72inline pred_iterator pred_begin(BasicBlock *BB) { return pred_iterator(BB); } 73inline pred_const_iterator pred_begin(const BasicBlock *BB) { 74 return pred_const_iterator(BB); 75} 76inline pred_iterator pred_end(BasicBlock *BB) { return pred_iterator(BB, true);} 77inline pred_const_iterator pred_end(const BasicBlock *BB) { 78 return pred_const_iterator(BB, true); 79} 80 81 82 83//===----------------------------------------------------------------------===// 84// BasicBlock succ_iterator definition 85//===----------------------------------------------------------------------===// 86 87template <class Term_, class BB_> // Successor Iterator 88class SuccIterator : public std::iterator<std::bidirectional_iterator_tag, 89 BB_, ptrdiff_t> { 90 const Term_ Term; 91 unsigned idx; 92 typedef std::iterator<std::bidirectional_iterator_tag, BB_, ptrdiff_t> super; 93public: 94 typedef SuccIterator<Term_, BB_> _Self; 95 typedef typename super::pointer pointer; 96 // TODO: This can be random access iterator, only operator[] missing. 97 98 inline SuccIterator(Term_ T) : Term(T), idx(0) { // begin iterator 99 assert(T && "getTerminator returned null!"); 100 } 101 inline SuccIterator(Term_ T, bool) // end iterator 102 : Term(T), idx(Term->getNumSuccessors()) { 103 assert(T && "getTerminator returned null!"); 104 } 105 106 inline const _Self &operator=(const _Self &I) { 107 assert(Term == I.Term &&"Cannot assign iterators to two different blocks!"); 108 idx = I.idx; 109 return *this; 110 } 111 112 inline bool index_is_valid (int idx) { 113 return idx >= 0 && (unsigned) idx < Term->getNumSuccessors(); 114 } 115 116 /// getSuccessorIndex - This is used to interface between code that wants to 117 /// operate on terminator instructions directly. 118 unsigned getSuccessorIndex() const { return idx; } 119 120 inline bool operator==(const _Self& x) const { return idx == x.idx; } 121 inline bool operator!=(const _Self& x) const { return !operator==(x); } 122 123 inline pointer operator*() const { return Term->getSuccessor(idx); } 124 inline pointer operator->() const { return operator*(); } 125 126 inline _Self& operator++() { ++idx; return *this; } // Preincrement 127 128 inline _Self operator++(int) { // Postincrement 129 _Self tmp = *this; ++*this; return tmp; 130 } 131 132 inline _Self& operator--() { --idx; return *this; } // Predecrement 133 inline _Self operator--(int) { // Postdecrement 134 _Self tmp = *this; --*this; return tmp; 135 } 136 137 inline bool operator<(const _Self& x) const { 138 assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 139 return idx < x.idx; 140 } 141 142 inline bool operator<=(const _Self& x) const { 143 assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 144 return idx <= x.idx; 145 } 146 inline bool operator>=(const _Self& x) const { 147 assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 148 return idx >= x.idx; 149 } 150 151 inline bool operator>(const _Self& x) const { 152 return idx > x.idx; 153 assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 154 } 155 156 inline _Self& operator+=(int Right) { 157 unsigned new_idx = idx + Right; 158 assert(index_is_valid(new_idx) && "Iterator index out of bound"); 159 idx = new_idx; 160 return *this; 161 } 162 163 inline _Self operator+(int Right) { 164 _Self tmp = *this; 165 tmp += Right; 166 return tmp; 167 } 168 169 inline _Self& operator-=(int Right) { 170 return operator+=(-Right); 171 } 172 173 inline _Self operator-(int Right) { 174 return operator+(-Right); 175 } 176 177 inline int operator-(const _Self& x) { 178 assert(Term == x.Term && "Cannot work on iterators of different blocks!"); 179 int distance = idx - x.idx; 180 return distance; 181 } 182 183 // This works for read access, however write access is difficult as changes 184 // to Term are only possible with Term->setSuccessor(idx). Pointers that can 185 // be modified are not available. 186 // 187 // inline pointer operator[](int offset) { 188 // _Self tmp = *this; 189 // tmp += offset; 190 // return tmp.operator*(); 191 // } 192 193 /// Get the source BB of this iterator. 194 inline BB_ *getSource() { 195 return Term->getParent(); 196 } 197}; 198 199typedef SuccIterator<TerminatorInst*, BasicBlock> succ_iterator; 200typedef SuccIterator<const TerminatorInst*, 201 const BasicBlock> succ_const_iterator; 202 203inline succ_iterator succ_begin(BasicBlock *BB) { 204 return succ_iterator(BB->getTerminator()); 205} 206inline succ_const_iterator succ_begin(const BasicBlock *BB) { 207 return succ_const_iterator(BB->getTerminator()); 208} 209inline succ_iterator succ_end(BasicBlock *BB) { 210 return succ_iterator(BB->getTerminator(), true); 211} 212inline succ_const_iterator succ_end(const BasicBlock *BB) { 213 return succ_const_iterator(BB->getTerminator(), true); 214} 215 216 217 218//===--------------------------------------------------------------------===// 219// GraphTraits specializations for basic block graphs (CFGs) 220//===--------------------------------------------------------------------===// 221 222// Provide specializations of GraphTraits to be able to treat a function as a 223// graph of basic blocks... 224 225template <> struct GraphTraits<BasicBlock*> { 226 typedef BasicBlock NodeType; 227 typedef succ_iterator ChildIteratorType; 228 229 static NodeType *getEntryNode(BasicBlock *BB) { return BB; } 230 static inline ChildIteratorType child_begin(NodeType *N) { 231 return succ_begin(N); 232 } 233 static inline ChildIteratorType child_end(NodeType *N) { 234 return succ_end(N); 235 } 236}; 237 238template <> struct GraphTraits<const BasicBlock*> { 239 typedef const BasicBlock NodeType; 240 typedef succ_const_iterator ChildIteratorType; 241 242 static NodeType *getEntryNode(const BasicBlock *BB) { return BB; } 243 244 static inline ChildIteratorType child_begin(NodeType *N) { 245 return succ_begin(N); 246 } 247 static inline ChildIteratorType child_end(NodeType *N) { 248 return succ_end(N); 249 } 250}; 251 252// Provide specializations of GraphTraits to be able to treat a function as a 253// graph of basic blocks... and to walk it in inverse order. Inverse order for 254// a function is considered to be when traversing the predecessor edges of a BB 255// instead of the successor edges. 256// 257template <> struct GraphTraits<Inverse<BasicBlock*> > { 258 typedef BasicBlock NodeType; 259 typedef pred_iterator ChildIteratorType; 260 static NodeType *getEntryNode(Inverse<BasicBlock *> G) { return G.Graph; } 261 static inline ChildIteratorType child_begin(NodeType *N) { 262 return pred_begin(N); 263 } 264 static inline ChildIteratorType child_end(NodeType *N) { 265 return pred_end(N); 266 } 267}; 268 269template <> struct GraphTraits<Inverse<const BasicBlock*> > { 270 typedef const BasicBlock NodeType; 271 typedef pred_const_iterator ChildIteratorType; 272 static NodeType *getEntryNode(Inverse<const BasicBlock*> G) { 273 return G.Graph; 274 } 275 static inline ChildIteratorType child_begin(NodeType *N) { 276 return pred_begin(N); 277 } 278 static inline ChildIteratorType child_end(NodeType *N) { 279 return pred_end(N); 280 } 281}; 282 283 284 285//===--------------------------------------------------------------------===// 286// GraphTraits specializations for function basic block graphs (CFGs) 287//===--------------------------------------------------------------------===// 288 289// Provide specializations of GraphTraits to be able to treat a function as a 290// graph of basic blocks... these are the same as the basic block iterators, 291// except that the root node is implicitly the first node of the function. 292// 293template <> struct GraphTraits<Function*> : public GraphTraits<BasicBlock*> { 294 static NodeType *getEntryNode(Function *F) { return &F->getEntryBlock(); } 295 296 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph 297 typedef Function::iterator nodes_iterator; 298 static nodes_iterator nodes_begin(Function *F) { return F->begin(); } 299 static nodes_iterator nodes_end (Function *F) { return F->end(); } 300}; 301template <> struct GraphTraits<const Function*> : 302 public GraphTraits<const BasicBlock*> { 303 static NodeType *getEntryNode(const Function *F) {return &F->getEntryBlock();} 304 305 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph 306 typedef Function::const_iterator nodes_iterator; 307 static nodes_iterator nodes_begin(const Function *F) { return F->begin(); } 308 static nodes_iterator nodes_end (const Function *F) { return F->end(); } 309}; 310 311 312// Provide specializations of GraphTraits to be able to treat a function as a 313// graph of basic blocks... and to walk it in inverse order. Inverse order for 314// a function is considered to be when traversing the predecessor edges of a BB 315// instead of the successor edges. 316// 317template <> struct GraphTraits<Inverse<Function*> > : 318 public GraphTraits<Inverse<BasicBlock*> > { 319 static NodeType *getEntryNode(Inverse<Function*> G) { 320 return &G.Graph->getEntryBlock(); 321 } 322}; 323template <> struct GraphTraits<Inverse<const Function*> > : 324 public GraphTraits<Inverse<const BasicBlock*> > { 325 static NodeType *getEntryNode(Inverse<const Function *> G) { 326 return &G.Graph->getEntryBlock(); 327 } 328}; 329 330} // End llvm namespace 331 332#endif 333