1//===- 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_IR_CFG_H 16#define LLVM_IR_CFG_H 17 18#include "llvm/ADT/GraphTraits.h" 19#include "llvm/ADT/iterator_range.h" 20#include "llvm/IR/Function.h" 21#include "llvm/IR/InstrTypes.h" 22 23namespace llvm { 24 25//===----------------------------------------------------------------------===// 26// BasicBlock pred_iterator definition 27//===----------------------------------------------------------------------===// 28 29template <class Ptr, class USE_iterator> // Predecessor Iterator 30class PredIterator : public std::iterator<std::forward_iterator_tag, 31 Ptr, ptrdiff_t, Ptr*, Ptr*> { 32 typedef std::iterator<std::forward_iterator_tag, Ptr, ptrdiff_t, Ptr*, 33 Ptr*> super; 34 typedef PredIterator<Ptr, USE_iterator> Self; 35 USE_iterator It; 36 37 inline void advancePastNonTerminators() { 38 // Loop to ignore non-terminator uses (for example BlockAddresses). 39 while (!It.atEnd() && !isa<TerminatorInst>(*It)) 40 ++It; 41 } 42 43public: 44 typedef typename super::pointer pointer; 45 typedef typename super::reference reference; 46 47 PredIterator() {} 48 explicit inline PredIterator(Ptr *bb) : It(bb->user_begin()) { 49 advancePastNonTerminators(); 50 } 51 inline PredIterator(Ptr *bb, bool) : It(bb->user_end()) {} 52 53 inline bool operator==(const Self& x) const { return It == x.It; } 54 inline bool operator!=(const Self& x) const { return !operator==(x); } 55 56 inline reference operator*() const { 57 assert(!It.atEnd() && "pred_iterator out of range!"); 58 return cast<TerminatorInst>(*It)->getParent(); 59 } 60 inline pointer *operator->() const { return &operator*(); } 61 62 inline Self& operator++() { // Preincrement 63 assert(!It.atEnd() && "pred_iterator out of range!"); 64 ++It; advancePastNonTerminators(); 65 return *this; 66 } 67 68 inline Self operator++(int) { // Postincrement 69 Self tmp = *this; ++*this; return tmp; 70 } 71 72 /// getOperandNo - Return the operand number in the predecessor's 73 /// terminator of the successor. 74 unsigned getOperandNo() const { 75 return It.getOperandNo(); 76 } 77 78 /// getUse - Return the operand Use in the predecessor's terminator 79 /// of the successor. 80 Use &getUse() const { 81 return It.getUse(); 82 } 83}; 84 85typedef PredIterator<BasicBlock, Value::user_iterator> pred_iterator; 86typedef PredIterator<const BasicBlock, 87 Value::const_user_iterator> const_pred_iterator; 88typedef llvm::iterator_range<pred_iterator> pred_range; 89typedef llvm::iterator_range<const_pred_iterator> pred_const_range; 90 91inline pred_iterator pred_begin(BasicBlock *BB) { return pred_iterator(BB); } 92inline const_pred_iterator pred_begin(const BasicBlock *BB) { 93 return const_pred_iterator(BB); 94} 95inline pred_iterator pred_end(BasicBlock *BB) { return pred_iterator(BB, true);} 96inline const_pred_iterator pred_end(const BasicBlock *BB) { 97 return const_pred_iterator(BB, true); 98} 99inline bool pred_empty(const BasicBlock *BB) { 100 return pred_begin(BB) == pred_end(BB); 101} 102inline pred_range predecessors(BasicBlock *BB) { 103 return pred_range(pred_begin(BB), pred_end(BB)); 104} 105inline pred_const_range predecessors(const BasicBlock *BB) { 106 return pred_const_range(pred_begin(BB), pred_end(BB)); 107} 108 109//===----------------------------------------------------------------------===// 110// BasicBlock succ_iterator definition 111//===----------------------------------------------------------------------===// 112 113template <class Term_, class BB_> // Successor Iterator 114class SuccIterator : public std::iterator<std::random_access_iterator_tag, BB_, 115 int, BB_ *, BB_ *> { 116 typedef std::iterator<std::random_access_iterator_tag, BB_, int, BB_ *, BB_ *> 117 super; 118 119public: 120 typedef typename super::pointer pointer; 121 typedef typename super::reference reference; 122 123private: 124 Term_ Term; 125 unsigned idx; 126 typedef SuccIterator<Term_, BB_> Self; 127 128 inline bool index_is_valid(int idx) { 129 return idx >= 0 && (unsigned) idx < Term->getNumSuccessors(); 130 } 131 132 /// \brief Proxy object to allow write access in operator[] 133 class SuccessorProxy { 134 Self it; 135 136 public: 137 explicit SuccessorProxy(const Self &it) : it(it) {} 138 139 SuccessorProxy(const SuccessorProxy&) = default; 140 141 SuccessorProxy &operator=(SuccessorProxy r) { 142 *this = reference(r); 143 return *this; 144 } 145 146 SuccessorProxy &operator=(reference r) { 147 it.Term->setSuccessor(it.idx, r); 148 return *this; 149 } 150 151 operator reference() const { return *it; } 152 }; 153 154public: 155 explicit inline SuccIterator(Term_ T) : Term(T), idx(0) {// begin iterator 156 } 157 inline SuccIterator(Term_ T, bool) // end iterator 158 : Term(T) { 159 if (Term) 160 idx = Term->getNumSuccessors(); 161 else 162 // Term == NULL happens, if a basic block is not fully constructed and 163 // consequently getTerminator() returns NULL. In this case we construct a 164 // SuccIterator which describes a basic block that has zero successors. 165 // Defining SuccIterator for incomplete and malformed CFGs is especially 166 // useful for debugging. 167 idx = 0; 168 } 169 170 /// getSuccessorIndex - This is used to interface between code that wants to 171 /// operate on terminator instructions directly. 172 unsigned getSuccessorIndex() const { return idx; } 173 174 inline bool operator==(const Self& x) const { return idx == x.idx; } 175 inline bool operator!=(const Self& x) const { return !operator==(x); } 176 177 inline reference operator*() const { return Term->getSuccessor(idx); } 178 inline pointer operator->() const { return operator*(); } 179 180 inline Self& operator++() { ++idx; return *this; } // Preincrement 181 182 inline Self operator++(int) { // Postincrement 183 Self tmp = *this; ++*this; return tmp; 184 } 185 186 inline Self& operator--() { --idx; return *this; } // Predecrement 187 inline Self operator--(int) { // Postdecrement 188 Self tmp = *this; --*this; return tmp; 189 } 190 191 inline bool operator<(const Self& x) const { 192 assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 193 return idx < x.idx; 194 } 195 196 inline bool operator<=(const Self& x) const { 197 assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 198 return idx <= x.idx; 199 } 200 inline bool operator>=(const Self& x) const { 201 assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 202 return idx >= x.idx; 203 } 204 205 inline bool operator>(const Self& x) const { 206 assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 207 return idx > x.idx; 208 } 209 210 inline Self& operator+=(int Right) { 211 unsigned new_idx = idx + Right; 212 assert(index_is_valid(new_idx) && "Iterator index out of bound"); 213 idx = new_idx; 214 return *this; 215 } 216 217 inline Self operator+(int Right) const { 218 Self tmp = *this; 219 tmp += Right; 220 return tmp; 221 } 222 223 inline Self& operator-=(int Right) { 224 return operator+=(-Right); 225 } 226 227 inline Self operator-(int Right) const { 228 return operator+(-Right); 229 } 230 231 inline int operator-(const Self& x) const { 232 assert(Term == x.Term && "Cannot work on iterators of different blocks!"); 233 int distance = idx - x.idx; 234 return distance; 235 } 236 237 inline SuccessorProxy operator[](int offset) { 238 Self tmp = *this; 239 tmp += offset; 240 return SuccessorProxy(tmp); 241 } 242 243 /// Get the source BB of this iterator. 244 inline BB_ *getSource() { 245 assert(Term && "Source not available, if basic block was malformed"); 246 return Term->getParent(); 247 } 248}; 249 250typedef SuccIterator<TerminatorInst*, BasicBlock> succ_iterator; 251typedef SuccIterator<const TerminatorInst*, 252 const BasicBlock> succ_const_iterator; 253typedef llvm::iterator_range<succ_iterator> succ_range; 254typedef llvm::iterator_range<succ_const_iterator> succ_const_range; 255 256inline succ_iterator succ_begin(BasicBlock *BB) { 257 return succ_iterator(BB->getTerminator()); 258} 259inline succ_const_iterator succ_begin(const BasicBlock *BB) { 260 return succ_const_iterator(BB->getTerminator()); 261} 262inline succ_iterator succ_end(BasicBlock *BB) { 263 return succ_iterator(BB->getTerminator(), true); 264} 265inline succ_const_iterator succ_end(const BasicBlock *BB) { 266 return succ_const_iterator(BB->getTerminator(), true); 267} 268inline bool succ_empty(const BasicBlock *BB) { 269 return succ_begin(BB) == succ_end(BB); 270} 271inline succ_range successors(BasicBlock *BB) { 272 return succ_range(succ_begin(BB), succ_end(BB)); 273} 274inline succ_const_range successors(const BasicBlock *BB) { 275 return succ_const_range(succ_begin(BB), succ_end(BB)); 276} 277 278 279template <typename T, typename U> struct isPodLike<SuccIterator<T, U> > { 280 static const bool value = isPodLike<T>::value; 281}; 282 283 284 285//===--------------------------------------------------------------------===// 286// GraphTraits specializations for 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... 291 292template <> struct GraphTraits<BasicBlock*> { 293 typedef BasicBlock NodeType; 294 typedef succ_iterator ChildIteratorType; 295 296 static NodeType *getEntryNode(BasicBlock *BB) { return BB; } 297 static inline ChildIteratorType child_begin(NodeType *N) { 298 return succ_begin(N); 299 } 300 static inline ChildIteratorType child_end(NodeType *N) { 301 return succ_end(N); 302 } 303}; 304 305template <> struct GraphTraits<const BasicBlock*> { 306 typedef const BasicBlock NodeType; 307 typedef succ_const_iterator ChildIteratorType; 308 309 static NodeType *getEntryNode(const BasicBlock *BB) { return BB; } 310 311 static inline ChildIteratorType child_begin(NodeType *N) { 312 return succ_begin(N); 313 } 314 static inline ChildIteratorType child_end(NodeType *N) { 315 return succ_end(N); 316 } 317}; 318 319// Provide specializations of GraphTraits to be able to treat a function as a 320// graph of basic blocks... and to walk it in inverse order. Inverse order for 321// a function is considered to be when traversing the predecessor edges of a BB 322// instead of the successor edges. 323// 324template <> struct GraphTraits<Inverse<BasicBlock*> > { 325 typedef BasicBlock NodeType; 326 typedef pred_iterator ChildIteratorType; 327 static NodeType *getEntryNode(Inverse<BasicBlock *> G) { return G.Graph; } 328 static inline ChildIteratorType child_begin(NodeType *N) { 329 return pred_begin(N); 330 } 331 static inline ChildIteratorType child_end(NodeType *N) { 332 return pred_end(N); 333 } 334}; 335 336template <> struct GraphTraits<Inverse<const BasicBlock*> > { 337 typedef const BasicBlock NodeType; 338 typedef const_pred_iterator ChildIteratorType; 339 static NodeType *getEntryNode(Inverse<const BasicBlock*> G) { 340 return G.Graph; 341 } 342 static inline ChildIteratorType child_begin(NodeType *N) { 343 return pred_begin(N); 344 } 345 static inline ChildIteratorType child_end(NodeType *N) { 346 return pred_end(N); 347 } 348}; 349 350 351 352//===--------------------------------------------------------------------===// 353// GraphTraits specializations for function basic block graphs (CFGs) 354//===--------------------------------------------------------------------===// 355 356// Provide specializations of GraphTraits to be able to treat a function as a 357// graph of basic blocks... these are the same as the basic block iterators, 358// except that the root node is implicitly the first node of the function. 359// 360template <> struct GraphTraits<Function*> : public GraphTraits<BasicBlock*> { 361 static NodeType *getEntryNode(Function *F) { return &F->getEntryBlock(); } 362 363 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph 364 typedef Function::iterator nodes_iterator; 365 static nodes_iterator nodes_begin(Function *F) { return F->begin(); } 366 static nodes_iterator nodes_end (Function *F) { return F->end(); } 367 static size_t size (Function *F) { return F->size(); } 368}; 369template <> struct GraphTraits<const Function*> : 370 public GraphTraits<const BasicBlock*> { 371 static NodeType *getEntryNode(const Function *F) {return &F->getEntryBlock();} 372 373 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph 374 typedef Function::const_iterator nodes_iterator; 375 static nodes_iterator nodes_begin(const Function *F) { return F->begin(); } 376 static nodes_iterator nodes_end (const Function *F) { return F->end(); } 377 static size_t size (const Function *F) { return F->size(); } 378}; 379 380 381// Provide specializations of GraphTraits to be able to treat a function as a 382// graph of basic blocks... and to walk it in inverse order. Inverse order for 383// a function is considered to be when traversing the predecessor edges of a BB 384// instead of the successor edges. 385// 386template <> struct GraphTraits<Inverse<Function*> > : 387 public GraphTraits<Inverse<BasicBlock*> > { 388 static NodeType *getEntryNode(Inverse<Function*> G) { 389 return &G.Graph->getEntryBlock(); 390 } 391}; 392template <> struct GraphTraits<Inverse<const Function*> > : 393 public GraphTraits<Inverse<const BasicBlock*> > { 394 static NodeType *getEntryNode(Inverse<const Function *> G) { 395 return &G.Graph->getEntryBlock(); 396 } 397}; 398 399} // End llvm namespace 400 401#endif 402