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 22 namespace llvm { 23 24 //===----------------------------------------------------------------------===// 25 // BasicBlock pred_iterator definition 26 //===----------------------------------------------------------------------===// 27 28 template <class Ptr, class USE_iterator> // Predecessor Iterator 29 class 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 typedef PredIterator<Ptr, USE_iterator> Self; 33 USE_iterator It; 34 35 inline void advancePastNonTerminators() { 36 // Loop to ignore non terminator uses (for example BlockAddresses). 37 while (!It.atEnd() && !isa<TerminatorInst>(*It)) 38 ++It; 39 } 40 41 public: 42 typedef typename super::pointer pointer; 43 44 PredIterator() {} 45 explicit inline PredIterator(Ptr *bb) : It(bb->use_begin()) { 46 advancePastNonTerminators(); 47 } 48 inline PredIterator(Ptr *bb, bool) : It(bb->use_end()) {} 49 50 inline bool operator==(const Self& x) const { return It == x.It; } 51 inline bool operator!=(const Self& x) const { return !operator==(x); } 52 53 inline pointer operator*() const { 54 assert(!It.atEnd() && "pred_iterator out of range!"); 55 return cast<TerminatorInst>(*It)->getParent(); 56 } 57 inline pointer *operator->() const { return &operator*(); } 58 59 inline Self& operator++() { // Preincrement 60 assert(!It.atEnd() && "pred_iterator out of range!"); 61 ++It; advancePastNonTerminators(); 62 return *this; 63 } 64 65 inline Self operator++(int) { // Postincrement 66 Self tmp = *this; ++*this; return tmp; 67 } 68 69 /// getOperandNo - Return the operand number in the predecessor's 70 /// terminator of the successor. 71 unsigned getOperandNo() const { 72 return It.getOperandNo(); 73 } 74 }; 75 76 typedef PredIterator<BasicBlock, Value::use_iterator> pred_iterator; 77 typedef PredIterator<const BasicBlock, 78 Value::const_use_iterator> const_pred_iterator; 79 80 inline pred_iterator pred_begin(BasicBlock *BB) { return pred_iterator(BB); } 81 inline const_pred_iterator pred_begin(const BasicBlock *BB) { 82 return const_pred_iterator(BB); 83 } 84 inline pred_iterator pred_end(BasicBlock *BB) { return pred_iterator(BB, true);} 85 inline const_pred_iterator pred_end(const BasicBlock *BB) { 86 return const_pred_iterator(BB, true); 87 } 88 89 90 91 //===----------------------------------------------------------------------===// 92 // BasicBlock succ_iterator definition 93 //===----------------------------------------------------------------------===// 94 95 template <class Term_, class BB_> // Successor Iterator 96 class SuccIterator : public std::iterator<std::bidirectional_iterator_tag, 97 BB_, ptrdiff_t> { 98 const Term_ Term; 99 unsigned idx; 100 typedef std::iterator<std::bidirectional_iterator_tag, BB_, ptrdiff_t> super; 101 typedef SuccIterator<Term_, BB_> Self; 102 103 inline bool index_is_valid(int idx) { 104 return idx >= 0 && (unsigned) idx < Term->getNumSuccessors(); 105 } 106 107 public: 108 typedef typename super::pointer pointer; 109 // TODO: This can be random access iterator, only operator[] missing. 110 111 explicit inline SuccIterator(Term_ T) : Term(T), idx(0) {// begin iterator 112 } 113 inline SuccIterator(Term_ T, bool) // end iterator 114 : Term(T) { 115 if (Term) 116 idx = Term->getNumSuccessors(); 117 else 118 // Term == NULL happens, if a basic block is not fully constructed and 119 // consequently getTerminator() returns NULL. In this case we construct a 120 // SuccIterator which describes a basic block that has zero successors. 121 // Defining SuccIterator for incomplete and malformed CFGs is especially 122 // useful for debugging. 123 idx = 0; 124 } 125 126 inline const Self &operator=(const Self &I) { 127 assert(Term == I.Term &&"Cannot assign iterators to two different blocks!"); 128 idx = I.idx; 129 return *this; 130 } 131 132 /// getSuccessorIndex - This is used to interface between code that wants to 133 /// operate on terminator instructions directly. 134 unsigned getSuccessorIndex() const { return idx; } 135 136 inline bool operator==(const Self& x) const { return idx == x.idx; } 137 inline bool operator!=(const Self& x) const { return !operator==(x); } 138 139 inline pointer operator*() const { return Term->getSuccessor(idx); } 140 inline pointer operator->() const { return operator*(); } 141 142 inline Self& operator++() { ++idx; return *this; } // Preincrement 143 144 inline Self operator++(int) { // Postincrement 145 Self tmp = *this; ++*this; return tmp; 146 } 147 148 inline Self& operator--() { --idx; return *this; } // Predecrement 149 inline Self operator--(int) { // Postdecrement 150 Self tmp = *this; --*this; return tmp; 151 } 152 153 inline bool operator<(const Self& x) const { 154 assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 155 return idx < x.idx; 156 } 157 158 inline bool operator<=(const Self& x) const { 159 assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 160 return idx <= x.idx; 161 } 162 inline bool operator>=(const Self& x) const { 163 assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 164 return idx >= x.idx; 165 } 166 167 inline bool operator>(const Self& x) const { 168 assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 169 return idx > x.idx; 170 } 171 172 inline Self& operator+=(int Right) { 173 unsigned new_idx = idx + Right; 174 assert(index_is_valid(new_idx) && "Iterator index out of bound"); 175 idx = new_idx; 176 return *this; 177 } 178 179 inline Self operator+(int Right) { 180 Self tmp = *this; 181 tmp += Right; 182 return tmp; 183 } 184 185 inline Self& operator-=(int Right) { 186 return operator+=(-Right); 187 } 188 189 inline Self operator-(int Right) { 190 return operator+(-Right); 191 } 192 193 inline int operator-(const Self& x) { 194 assert(Term == x.Term && "Cannot work on iterators of different blocks!"); 195 int distance = idx - x.idx; 196 return distance; 197 } 198 199 // This works for read access, however write access is difficult as changes 200 // to Term are only possible with Term->setSuccessor(idx). Pointers that can 201 // be modified are not available. 202 // 203 // inline pointer operator[](int offset) { 204 // Self tmp = *this; 205 // tmp += offset; 206 // return tmp.operator*(); 207 // } 208 209 /// Get the source BB of this iterator. 210 inline BB_ *getSource() { 211 assert(Term && "Source not available, if basic block was malformed"); 212 return Term->getParent(); 213 } 214 }; 215 216 typedef SuccIterator<TerminatorInst*, BasicBlock> succ_iterator; 217 typedef SuccIterator<const TerminatorInst*, 218 const BasicBlock> succ_const_iterator; 219 220 inline succ_iterator succ_begin(BasicBlock *BB) { 221 return succ_iterator(BB->getTerminator()); 222 } 223 inline succ_const_iterator succ_begin(const BasicBlock *BB) { 224 return succ_const_iterator(BB->getTerminator()); 225 } 226 inline succ_iterator succ_end(BasicBlock *BB) { 227 return succ_iterator(BB->getTerminator(), true); 228 } 229 inline succ_const_iterator succ_end(const BasicBlock *BB) { 230 return succ_const_iterator(BB->getTerminator(), true); 231 } 232 233 234 235 //===--------------------------------------------------------------------===// 236 // GraphTraits specializations for basic block graphs (CFGs) 237 //===--------------------------------------------------------------------===// 238 239 // Provide specializations of GraphTraits to be able to treat a function as a 240 // graph of basic blocks... 241 242 template <> struct GraphTraits<BasicBlock*> { 243 typedef BasicBlock NodeType; 244 typedef succ_iterator ChildIteratorType; 245 246 static NodeType *getEntryNode(BasicBlock *BB) { return BB; } 247 static inline ChildIteratorType child_begin(NodeType *N) { 248 return succ_begin(N); 249 } 250 static inline ChildIteratorType child_end(NodeType *N) { 251 return succ_end(N); 252 } 253 }; 254 255 template <> struct GraphTraits<const BasicBlock*> { 256 typedef const BasicBlock NodeType; 257 typedef succ_const_iterator ChildIteratorType; 258 259 static NodeType *getEntryNode(const BasicBlock *BB) { return BB; } 260 261 static inline ChildIteratorType child_begin(NodeType *N) { 262 return succ_begin(N); 263 } 264 static inline ChildIteratorType child_end(NodeType *N) { 265 return succ_end(N); 266 } 267 }; 268 269 // Provide specializations of GraphTraits to be able to treat a function as a 270 // graph of basic blocks... and to walk it in inverse order. Inverse order for 271 // a function is considered to be when traversing the predecessor edges of a BB 272 // instead of the successor edges. 273 // 274 template <> struct GraphTraits<Inverse<BasicBlock*> > { 275 typedef BasicBlock NodeType; 276 typedef pred_iterator ChildIteratorType; 277 static NodeType *getEntryNode(Inverse<BasicBlock *> G) { return G.Graph; } 278 static inline ChildIteratorType child_begin(NodeType *N) { 279 return pred_begin(N); 280 } 281 static inline ChildIteratorType child_end(NodeType *N) { 282 return pred_end(N); 283 } 284 }; 285 286 template <> struct GraphTraits<Inverse<const BasicBlock*> > { 287 typedef const BasicBlock NodeType; 288 typedef const_pred_iterator ChildIteratorType; 289 static NodeType *getEntryNode(Inverse<const BasicBlock*> G) { 290 return G.Graph; 291 } 292 static inline ChildIteratorType child_begin(NodeType *N) { 293 return pred_begin(N); 294 } 295 static inline ChildIteratorType child_end(NodeType *N) { 296 return pred_end(N); 297 } 298 }; 299 300 301 302 //===--------------------------------------------------------------------===// 303 // GraphTraits specializations for function basic block graphs (CFGs) 304 //===--------------------------------------------------------------------===// 305 306 // Provide specializations of GraphTraits to be able to treat a function as a 307 // graph of basic blocks... these are the same as the basic block iterators, 308 // except that the root node is implicitly the first node of the function. 309 // 310 template <> struct GraphTraits<Function*> : public GraphTraits<BasicBlock*> { 311 static NodeType *getEntryNode(Function *F) { return &F->getEntryBlock(); } 312 313 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph 314 typedef Function::iterator nodes_iterator; 315 static nodes_iterator nodes_begin(Function *F) { return F->begin(); } 316 static nodes_iterator nodes_end (Function *F) { return F->end(); } 317 }; 318 template <> struct GraphTraits<const Function*> : 319 public GraphTraits<const BasicBlock*> { 320 static NodeType *getEntryNode(const Function *F) {return &F->getEntryBlock();} 321 322 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph 323 typedef Function::const_iterator nodes_iterator; 324 static nodes_iterator nodes_begin(const Function *F) { return F->begin(); } 325 static nodes_iterator nodes_end (const Function *F) { return F->end(); } 326 }; 327 328 329 // Provide specializations of GraphTraits to be able to treat a function as a 330 // graph of basic blocks... and to walk it in inverse order. Inverse order for 331 // a function is considered to be when traversing the predecessor edges of a BB 332 // instead of the successor edges. 333 // 334 template <> struct GraphTraits<Inverse<Function*> > : 335 public GraphTraits<Inverse<BasicBlock*> > { 336 static NodeType *getEntryNode(Inverse<Function*> G) { 337 return &G.Graph->getEntryBlock(); 338 } 339 }; 340 template <> struct GraphTraits<Inverse<const Function*> > : 341 public GraphTraits<Inverse<const BasicBlock*> > { 342 static NodeType *getEntryNode(Inverse<const Function *> G) { 343 return &G.Graph->getEntryBlock(); 344 } 345 }; 346 347 } // End llvm namespace 348 349 #endif 350
