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/IR/Function.h" 20#include "llvm/IR/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, Ptr*, Ptr*> { 31 typedef std::iterator<std::forward_iterator_tag, Ptr, ptrdiff_t, Ptr*, 32 Ptr*> super; 33 typedef PredIterator<Ptr, USE_iterator> Self; 34 USE_iterator It; 35 36 inline void advancePastNonTerminators() { 37 // Loop to ignore non-terminator uses (for example BlockAddresses). 38 while (!It.atEnd() && !isa<TerminatorInst>(*It)) 39 ++It; 40 } 41 42public: 43 typedef typename super::pointer pointer; 44 typedef typename super::reference reference; 45 46 PredIterator() {} 47 explicit inline PredIterator(Ptr *bb) : It(bb->user_begin()) { 48 advancePastNonTerminators(); 49 } 50 inline PredIterator(Ptr *bb, bool) : It(bb->user_end()) {} 51 52 inline bool operator==(const Self& x) const { return It == x.It; } 53 inline bool operator!=(const Self& x) const { return !operator==(x); } 54 55 inline reference operator*() const { 56 assert(!It.atEnd() && "pred_iterator out of range!"); 57 return cast<TerminatorInst>(*It)->getParent(); 58 } 59 inline pointer *operator->() const { return &operator*(); } 60 61 inline Self& operator++() { // Preincrement 62 assert(!It.atEnd() && "pred_iterator out of range!"); 63 ++It; advancePastNonTerminators(); 64 return *this; 65 } 66 67 inline Self operator++(int) { // Postincrement 68 Self tmp = *this; ++*this; return tmp; 69 } 70 71 /// getOperandNo - Return the operand number in the predecessor's 72 /// terminator of the successor. 73 unsigned getOperandNo() const { 74 return It.getOperandNo(); 75 } 76 77 /// getUse - Return the operand Use in the predecessor's terminator 78 /// of the successor. 79 Use &getUse() const { 80 return It.getUse(); 81 } 82}; 83 84typedef PredIterator<BasicBlock, Value::user_iterator> pred_iterator; 85typedef PredIterator<const BasicBlock, 86 Value::const_user_iterator> const_pred_iterator; 87 88inline pred_iterator pred_begin(BasicBlock *BB) { return pred_iterator(BB); } 89inline const_pred_iterator pred_begin(const BasicBlock *BB) { 90 return const_pred_iterator(BB); 91} 92inline pred_iterator pred_end(BasicBlock *BB) { return pred_iterator(BB, true);} 93inline const_pred_iterator pred_end(const BasicBlock *BB) { 94 return const_pred_iterator(BB, true); 95} 96 97 98 99//===----------------------------------------------------------------------===// 100// BasicBlock succ_iterator definition 101//===----------------------------------------------------------------------===// 102 103template <class Term_, class BB_> // Successor Iterator 104class SuccIterator : public std::iterator<std::random_access_iterator_tag, BB_, 105 int, BB_ *, BB_ *> { 106 typedef std::iterator<std::random_access_iterator_tag, BB_, int, BB_ *, BB_ *> 107 super; 108 109public: 110 typedef typename super::pointer pointer; 111 typedef typename super::reference reference; 112 113private: 114 const Term_ Term; 115 unsigned idx; 116 typedef SuccIterator<Term_, BB_> Self; 117 118 inline bool index_is_valid(int idx) { 119 return idx >= 0 && (unsigned) idx < Term->getNumSuccessors(); 120 } 121 122 /// \brief Proxy object to allow write access in operator[] 123 class SuccessorProxy { 124 Self it; 125 126 public: 127 explicit SuccessorProxy(const Self &it) : it(it) {} 128 129 SuccessorProxy &operator=(SuccessorProxy r) { 130 *this = reference(r); 131 return *this; 132 } 133 134 SuccessorProxy &operator=(reference r) { 135 it.Term->setSuccessor(it.idx, r); 136 return *this; 137 } 138 139 operator reference() const { return *it; } 140 }; 141 142public: 143 explicit inline SuccIterator(Term_ T) : Term(T), idx(0) {// begin iterator 144 } 145 inline SuccIterator(Term_ T, bool) // end iterator 146 : Term(T) { 147 if (Term) 148 idx = Term->getNumSuccessors(); 149 else 150 // Term == NULL happens, if a basic block is not fully constructed and 151 // consequently getTerminator() returns NULL. In this case we construct a 152 // SuccIterator which describes a basic block that has zero successors. 153 // Defining SuccIterator for incomplete and malformed CFGs is especially 154 // useful for debugging. 155 idx = 0; 156 } 157 158 inline const Self &operator=(const Self &I) { 159 assert(Term == I.Term &&"Cannot assign iterators to two different blocks!"); 160 idx = I.idx; 161 return *this; 162 } 163 164 /// getSuccessorIndex - This is used to interface between code that wants to 165 /// operate on terminator instructions directly. 166 unsigned getSuccessorIndex() const { return idx; } 167 168 inline bool operator==(const Self& x) const { return idx == x.idx; } 169 inline bool operator!=(const Self& x) const { return !operator==(x); } 170 171 inline reference operator*() const { return Term->getSuccessor(idx); } 172 inline pointer operator->() const { return operator*(); } 173 174 inline Self& operator++() { ++idx; return *this; } // Preincrement 175 176 inline Self operator++(int) { // Postincrement 177 Self tmp = *this; ++*this; return tmp; 178 } 179 180 inline Self& operator--() { --idx; return *this; } // Predecrement 181 inline Self operator--(int) { // Postdecrement 182 Self tmp = *this; --*this; return tmp; 183 } 184 185 inline bool operator<(const Self& x) const { 186 assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 187 return idx < x.idx; 188 } 189 190 inline bool operator<=(const Self& x) const { 191 assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 192 return idx <= x.idx; 193 } 194 inline bool operator>=(const Self& x) const { 195 assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 196 return idx >= x.idx; 197 } 198 199 inline bool operator>(const Self& x) const { 200 assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 201 return idx > x.idx; 202 } 203 204 inline Self& operator+=(int Right) { 205 unsigned new_idx = idx + Right; 206 assert(index_is_valid(new_idx) && "Iterator index out of bound"); 207 idx = new_idx; 208 return *this; 209 } 210 211 inline Self operator+(int Right) const { 212 Self tmp = *this; 213 tmp += Right; 214 return tmp; 215 } 216 217 inline Self& operator-=(int Right) { 218 return operator+=(-Right); 219 } 220 221 inline Self operator-(int Right) const { 222 return operator+(-Right); 223 } 224 225 inline int operator-(const Self& x) const { 226 assert(Term == x.Term && "Cannot work on iterators of different blocks!"); 227 int distance = idx - x.idx; 228 return distance; 229 } 230 231 inline SuccessorProxy operator[](int offset) { 232 Self tmp = *this; 233 tmp += offset; 234 return SuccessorProxy(tmp); 235 } 236 237 /// Get the source BB of this iterator. 238 inline BB_ *getSource() { 239 assert(Term && "Source not available, if basic block was malformed"); 240 return Term->getParent(); 241 } 242}; 243 244typedef SuccIterator<TerminatorInst*, BasicBlock> succ_iterator; 245typedef SuccIterator<const TerminatorInst*, 246 const BasicBlock> succ_const_iterator; 247 248inline succ_iterator succ_begin(BasicBlock *BB) { 249 return succ_iterator(BB->getTerminator()); 250} 251inline succ_const_iterator succ_begin(const BasicBlock *BB) { 252 return succ_const_iterator(BB->getTerminator()); 253} 254inline succ_iterator succ_end(BasicBlock *BB) { 255 return succ_iterator(BB->getTerminator(), true); 256} 257inline succ_const_iterator succ_end(const BasicBlock *BB) { 258 return succ_const_iterator(BB->getTerminator(), true); 259} 260 261template <typename T, typename U> struct isPodLike<SuccIterator<T, U> > { 262 static const bool value = isPodLike<T>::value; 263}; 264 265 266 267//===--------------------------------------------------------------------===// 268// GraphTraits specializations for basic block graphs (CFGs) 269//===--------------------------------------------------------------------===// 270 271// Provide specializations of GraphTraits to be able to treat a function as a 272// graph of basic blocks... 273 274template <> struct GraphTraits<BasicBlock*> { 275 typedef BasicBlock NodeType; 276 typedef succ_iterator ChildIteratorType; 277 278 static NodeType *getEntryNode(BasicBlock *BB) { return BB; } 279 static inline ChildIteratorType child_begin(NodeType *N) { 280 return succ_begin(N); 281 } 282 static inline ChildIteratorType child_end(NodeType *N) { 283 return succ_end(N); 284 } 285}; 286 287template <> struct GraphTraits<const BasicBlock*> { 288 typedef const BasicBlock NodeType; 289 typedef succ_const_iterator ChildIteratorType; 290 291 static NodeType *getEntryNode(const BasicBlock *BB) { return BB; } 292 293 static inline ChildIteratorType child_begin(NodeType *N) { 294 return succ_begin(N); 295 } 296 static inline ChildIteratorType child_end(NodeType *N) { 297 return succ_end(N); 298 } 299}; 300 301// Provide specializations of GraphTraits to be able to treat a function as a 302// graph of basic blocks... and to walk it in inverse order. Inverse order for 303// a function is considered to be when traversing the predecessor edges of a BB 304// instead of the successor edges. 305// 306template <> struct GraphTraits<Inverse<BasicBlock*> > { 307 typedef BasicBlock NodeType; 308 typedef pred_iterator ChildIteratorType; 309 static NodeType *getEntryNode(Inverse<BasicBlock *> G) { return G.Graph; } 310 static inline ChildIteratorType child_begin(NodeType *N) { 311 return pred_begin(N); 312 } 313 static inline ChildIteratorType child_end(NodeType *N) { 314 return pred_end(N); 315 } 316}; 317 318template <> struct GraphTraits<Inverse<const BasicBlock*> > { 319 typedef const BasicBlock NodeType; 320 typedef const_pred_iterator ChildIteratorType; 321 static NodeType *getEntryNode(Inverse<const BasicBlock*> G) { 322 return G.Graph; 323 } 324 static inline ChildIteratorType child_begin(NodeType *N) { 325 return pred_begin(N); 326 } 327 static inline ChildIteratorType child_end(NodeType *N) { 328 return pred_end(N); 329 } 330}; 331 332 333 334//===--------------------------------------------------------------------===// 335// GraphTraits specializations for function basic block graphs (CFGs) 336//===--------------------------------------------------------------------===// 337 338// Provide specializations of GraphTraits to be able to treat a function as a 339// graph of basic blocks... these are the same as the basic block iterators, 340// except that the root node is implicitly the first node of the function. 341// 342template <> struct GraphTraits<Function*> : public GraphTraits<BasicBlock*> { 343 static NodeType *getEntryNode(Function *F) { return &F->getEntryBlock(); } 344 345 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph 346 typedef Function::iterator nodes_iterator; 347 static nodes_iterator nodes_begin(Function *F) { return F->begin(); } 348 static nodes_iterator nodes_end (Function *F) { return F->end(); } 349 static size_t size (Function *F) { return F->size(); } 350}; 351template <> struct GraphTraits<const Function*> : 352 public GraphTraits<const BasicBlock*> { 353 static NodeType *getEntryNode(const Function *F) {return &F->getEntryBlock();} 354 355 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph 356 typedef Function::const_iterator nodes_iterator; 357 static nodes_iterator nodes_begin(const Function *F) { return F->begin(); } 358 static nodes_iterator nodes_end (const Function *F) { return F->end(); } 359 static size_t size (const Function *F) { return F->size(); } 360}; 361 362 363// Provide specializations of GraphTraits to be able to treat a function as a 364// graph of basic blocks... and to walk it in inverse order. Inverse order for 365// a function is considered to be when traversing the predecessor edges of a BB 366// instead of the successor edges. 367// 368template <> struct GraphTraits<Inverse<Function*> > : 369 public GraphTraits<Inverse<BasicBlock*> > { 370 static NodeType *getEntryNode(Inverse<Function*> G) { 371 return &G.Graph->getEntryBlock(); 372 } 373}; 374template <> struct GraphTraits<Inverse<const Function*> > : 375 public GraphTraits<Inverse<const BasicBlock*> > { 376 static NodeType *getEntryNode(Inverse<const Function *> G) { 377 return &G.Graph->getEntryBlock(); 378 } 379}; 380 381} // End llvm namespace 382 383#endif 384