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/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->use_begin()) { 48 advancePastNonTerminators(); 49 } 50 inline PredIterator(Ptr *bb, bool) : It(bb->use_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::use_iterator> pred_iterator; 85typedef PredIterator<const BasicBlock, 86 Value::const_use_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::bidirectional_iterator_tag, 105 BB_, ptrdiff_t, BB_*, BB_*> { 106 const Term_ Term; 107 unsigned idx; 108 typedef std::iterator<std::bidirectional_iterator_tag, BB_, ptrdiff_t, BB_*, 109 BB_*> super; 110 typedef SuccIterator<Term_, BB_> Self; 111 112 inline bool index_is_valid(int idx) { 113 return idx >= 0 && (unsigned) idx < Term->getNumSuccessors(); 114 } 115 116public: 117 typedef typename super::pointer pointer; 118 typedef typename super::reference reference; 119 // TODO: This can be random access iterator, only operator[] missing. 120 121 explicit inline SuccIterator(Term_ T) : Term(T), idx(0) {// begin iterator 122 } 123 inline SuccIterator(Term_ T, bool) // end iterator 124 : Term(T) { 125 if (Term) 126 idx = Term->getNumSuccessors(); 127 else 128 // Term == NULL happens, if a basic block is not fully constructed and 129 // consequently getTerminator() returns NULL. In this case we construct a 130 // SuccIterator which describes a basic block that has zero successors. 131 // Defining SuccIterator for incomplete and malformed CFGs is especially 132 // useful for debugging. 133 idx = 0; 134 } 135 136 inline const Self &operator=(const Self &I) { 137 assert(Term == I.Term &&"Cannot assign iterators to two different blocks!"); 138 idx = I.idx; 139 return *this; 140 } 141 142 /// getSuccessorIndex - This is used to interface between code that wants to 143 /// operate on terminator instructions directly. 144 unsigned getSuccessorIndex() const { return idx; } 145 146 inline bool operator==(const Self& x) const { return idx == x.idx; } 147 inline bool operator!=(const Self& x) const { return !operator==(x); } 148 149 inline reference operator*() const { return Term->getSuccessor(idx); } 150 inline pointer operator->() const { return operator*(); } 151 152 inline Self& operator++() { ++idx; return *this; } // Preincrement 153 154 inline Self operator++(int) { // Postincrement 155 Self tmp = *this; ++*this; return tmp; 156 } 157 158 inline Self& operator--() { --idx; return *this; } // Predecrement 159 inline Self operator--(int) { // Postdecrement 160 Self tmp = *this; --*this; return tmp; 161 } 162 163 inline bool operator<(const Self& x) const { 164 assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 165 return idx < x.idx; 166 } 167 168 inline bool operator<=(const Self& x) const { 169 assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 170 return idx <= x.idx; 171 } 172 inline bool operator>=(const Self& x) const { 173 assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 174 return idx >= x.idx; 175 } 176 177 inline bool operator>(const Self& x) const { 178 assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 179 return idx > x.idx; 180 } 181 182 inline Self& operator+=(int Right) { 183 unsigned new_idx = idx + Right; 184 assert(index_is_valid(new_idx) && "Iterator index out of bound"); 185 idx = new_idx; 186 return *this; 187 } 188 189 inline Self operator+(int Right) { 190 Self tmp = *this; 191 tmp += Right; 192 return tmp; 193 } 194 195 inline Self& operator-=(int Right) { 196 return operator+=(-Right); 197 } 198 199 inline Self operator-(int Right) { 200 return operator+(-Right); 201 } 202 203 inline int operator-(const Self& x) { 204 assert(Term == x.Term && "Cannot work on iterators of different blocks!"); 205 int distance = idx - x.idx; 206 return distance; 207 } 208 209 // This works for read access, however write access is difficult as changes 210 // to Term are only possible with Term->setSuccessor(idx). Pointers that can 211 // be modified are not available. 212 // 213 // inline pointer operator[](int offset) { 214 // Self tmp = *this; 215 // tmp += offset; 216 // return tmp.operator*(); 217 // } 218 219 /// Get the source BB of this iterator. 220 inline BB_ *getSource() { 221 assert(Term && "Source not available, if basic block was malformed"); 222 return Term->getParent(); 223 } 224}; 225 226typedef SuccIterator<TerminatorInst*, BasicBlock> succ_iterator; 227typedef SuccIterator<const TerminatorInst*, 228 const BasicBlock> succ_const_iterator; 229 230inline succ_iterator succ_begin(BasicBlock *BB) { 231 return succ_iterator(BB->getTerminator()); 232} 233inline succ_const_iterator succ_begin(const BasicBlock *BB) { 234 return succ_const_iterator(BB->getTerminator()); 235} 236inline succ_iterator succ_end(BasicBlock *BB) { 237 return succ_iterator(BB->getTerminator(), true); 238} 239inline succ_const_iterator succ_end(const BasicBlock *BB) { 240 return succ_const_iterator(BB->getTerminator(), true); 241} 242 243template <typename T, typename U> struct isPodLike<SuccIterator<T, U> > { 244 static const bool value = isPodLike<T>::value; 245}; 246 247 248 249//===--------------------------------------------------------------------===// 250// GraphTraits specializations for basic block graphs (CFGs) 251//===--------------------------------------------------------------------===// 252 253// Provide specializations of GraphTraits to be able to treat a function as a 254// graph of basic blocks... 255 256template <> struct GraphTraits<BasicBlock*> { 257 typedef BasicBlock NodeType; 258 typedef succ_iterator ChildIteratorType; 259 260 static NodeType *getEntryNode(BasicBlock *BB) { return BB; } 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 269template <> struct GraphTraits<const BasicBlock*> { 270 typedef const BasicBlock NodeType; 271 typedef succ_const_iterator ChildIteratorType; 272 273 static NodeType *getEntryNode(const BasicBlock *BB) { return BB; } 274 275 static inline ChildIteratorType child_begin(NodeType *N) { 276 return succ_begin(N); 277 } 278 static inline ChildIteratorType child_end(NodeType *N) { 279 return succ_end(N); 280 } 281}; 282 283// Provide specializations of GraphTraits to be able to treat a function as a 284// graph of basic blocks... and to walk it in inverse order. Inverse order for 285// a function is considered to be when traversing the predecessor edges of a BB 286// instead of the successor edges. 287// 288template <> struct GraphTraits<Inverse<BasicBlock*> > { 289 typedef BasicBlock NodeType; 290 typedef pred_iterator ChildIteratorType; 291 static NodeType *getEntryNode(Inverse<BasicBlock *> G) { return G.Graph; } 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 300template <> struct GraphTraits<Inverse<const BasicBlock*> > { 301 typedef const BasicBlock NodeType; 302 typedef const_pred_iterator ChildIteratorType; 303 static NodeType *getEntryNode(Inverse<const BasicBlock*> G) { 304 return G.Graph; 305 } 306 static inline ChildIteratorType child_begin(NodeType *N) { 307 return pred_begin(N); 308 } 309 static inline ChildIteratorType child_end(NodeType *N) { 310 return pred_end(N); 311 } 312}; 313 314 315 316//===--------------------------------------------------------------------===// 317// GraphTraits specializations for function basic block graphs (CFGs) 318//===--------------------------------------------------------------------===// 319 320// Provide specializations of GraphTraits to be able to treat a function as a 321// graph of basic blocks... these are the same as the basic block iterators, 322// except that the root node is implicitly the first node of the function. 323// 324template <> struct GraphTraits<Function*> : public GraphTraits<BasicBlock*> { 325 static NodeType *getEntryNode(Function *F) { return &F->getEntryBlock(); } 326 327 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph 328 typedef Function::iterator nodes_iterator; 329 static nodes_iterator nodes_begin(Function *F) { return F->begin(); } 330 static nodes_iterator nodes_end (Function *F) { return F->end(); } 331 static size_t size (Function *F) { return F->size(); } 332}; 333template <> struct GraphTraits<const Function*> : 334 public GraphTraits<const BasicBlock*> { 335 static NodeType *getEntryNode(const Function *F) {return &F->getEntryBlock();} 336 337 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph 338 typedef Function::const_iterator nodes_iterator; 339 static nodes_iterator nodes_begin(const Function *F) { return F->begin(); } 340 static nodes_iterator nodes_end (const Function *F) { return F->end(); } 341 static size_t size (const Function *F) { return F->size(); } 342}; 343 344 345// Provide specializations of GraphTraits to be able to treat a function as a 346// graph of basic blocks... and to walk it in inverse order. Inverse order for 347// a function is considered to be when traversing the predecessor edges of a BB 348// instead of the successor edges. 349// 350template <> struct GraphTraits<Inverse<Function*> > : 351 public GraphTraits<Inverse<BasicBlock*> > { 352 static NodeType *getEntryNode(Inverse<Function*> G) { 353 return &G.Graph->getEntryBlock(); 354 } 355}; 356template <> struct GraphTraits<Inverse<const Function*> > : 357 public GraphTraits<Inverse<const BasicBlock*> > { 358 static NodeType *getEntryNode(Inverse<const Function *> G) { 359 return &G.Graph->getEntryBlock(); 360 } 361}; 362 363} // End llvm namespace 364 365#endif 366