CFG.h revision 263508
1251877Speter//===-- llvm/Support/CFG.h - Process LLVM structures as graphs --*- C++ -*-===// 2251877Speter// 3251877Speter// The LLVM Compiler Infrastructure 4251877Speter// 5251877Speter// This file is distributed under the University of Illinois Open Source 6251877Speter// License. See LICENSE.TXT for details. 7251877Speter// 8251877Speter//===----------------------------------------------------------------------===// 9251877Speter// 10251877Speter// This file defines specializations of GraphTraits that allow Function and 11251877Speter// BasicBlock graphs to be treated as proper graphs for generic algorithms. 12251877Speter// 13251877Speter//===----------------------------------------------------------------------===// 14251877Speter 15251877Speter#ifndef LLVM_SUPPORT_CFG_H 16251877Speter#define LLVM_SUPPORT_CFG_H 17251877Speter 18251877Speter#include "llvm/ADT/GraphTraits.h" 19251877Speter#include "llvm/IR/Function.h" 20251877Speter#include "llvm/IR/InstrTypes.h" 21251877Speter 22251877Speternamespace llvm { 23251877Speter 24251877Speter//===----------------------------------------------------------------------===// 25251877Speter// BasicBlock pred_iterator definition 26251877Speter//===----------------------------------------------------------------------===// 27251877Speter 28251877Spetertemplate <class Ptr, class USE_iterator> // Predecessor Iterator 29251877Speterclass PredIterator : public std::iterator<std::forward_iterator_tag, 30251877Speter Ptr, ptrdiff_t, Ptr*, Ptr*> { 31251877Speter typedef std::iterator<std::forward_iterator_tag, Ptr, ptrdiff_t, Ptr*, 32251877Speter Ptr*> super; 33251877Speter typedef PredIterator<Ptr, USE_iterator> Self; 34251877Speter USE_iterator It; 35251877Speter 36251877Speter inline void advancePastNonTerminators() { 37251877Speter // Loop to ignore non terminator uses (for example BlockAddresses). 38251877Speter while (!It.atEnd() && !isa<TerminatorInst>(*It)) 39251877Speter ++It; 40251877Speter } 41251877Speter 42251877Speterpublic: 43251877Speter typedef typename super::pointer pointer; 44251877Speter typedef typename super::reference reference; 45251877Speter 46251877Speter PredIterator() {} 47251877Speter explicit inline PredIterator(Ptr *bb) : It(bb->use_begin()) { 48251877Speter advancePastNonTerminators(); 49251877Speter } 50251877Speter inline PredIterator(Ptr *bb, bool) : It(bb->use_end()) {} 51251877Speter 52251877Speter inline bool operator==(const Self& x) const { return It == x.It; } 53251877Speter inline bool operator!=(const Self& x) const { return !operator==(x); } 54251877Speter 55251877Speter inline reference operator*() const { 56251877Speter assert(!It.atEnd() && "pred_iterator out of range!"); 57251877Speter return cast<TerminatorInst>(*It)->getParent(); 58251877Speter } 59251877Speter inline pointer *operator->() const { return &operator*(); } 60251877Speter 61251877Speter inline Self& operator++() { // Preincrement 62251877Speter assert(!It.atEnd() && "pred_iterator out of range!"); 63251877Speter ++It; advancePastNonTerminators(); 64251877Speter return *this; 65251877Speter } 66251877Speter 67251877Speter inline Self operator++(int) { // Postincrement 68251877Speter Self tmp = *this; ++*this; return tmp; 69251877Speter } 70251877Speter 71251877Speter /// getOperandNo - Return the operand number in the predecessor's 72251877Speter /// terminator of the successor. 73251877Speter unsigned getOperandNo() const { 74251877Speter return It.getOperandNo(); 75251877Speter } 76251877Speter 77251877Speter /// getUse - Return the operand Use in the predecessor's terminator 78251877Speter /// of the successor. 79251877Speter Use &getUse() const { 80251877Speter return It.getUse(); 81251877Speter } 82251877Speter}; 83251877Speter 84251877Spetertypedef PredIterator<BasicBlock, Value::use_iterator> pred_iterator; 85251877Spetertypedef PredIterator<const BasicBlock, 86251877Speter Value::const_use_iterator> const_pred_iterator; 87251877Speter 88251877Speterinline pred_iterator pred_begin(BasicBlock *BB) { return pred_iterator(BB); } 89251877Speterinline const_pred_iterator pred_begin(const BasicBlock *BB) { 90251877Speter return const_pred_iterator(BB); 91251877Speter} 92251877Speterinline pred_iterator pred_end(BasicBlock *BB) { return pred_iterator(BB, true);} 93251877Speterinline const_pred_iterator pred_end(const BasicBlock *BB) { 94251877Speter return const_pred_iterator(BB, true); 95251877Speter} 96251877Speter 97251877Speter 98251877Speter 99251877Speter//===----------------------------------------------------------------------===// 100251877Speter// BasicBlock succ_iterator definition 101251877Speter//===----------------------------------------------------------------------===// 102251877Speter 103251877Spetertemplate <class Term_, class BB_> // Successor Iterator 104251877Speterclass SuccIterator : public std::iterator<std::bidirectional_iterator_tag, 105251877Speter BB_, ptrdiff_t, BB_*, BB_*> { 106251877Speter const Term_ Term; 107251877Speter unsigned idx; 108251877Speter typedef std::iterator<std::bidirectional_iterator_tag, BB_, ptrdiff_t, BB_*, 109251877Speter BB_*> super; 110251877Speter typedef SuccIterator<Term_, BB_> Self; 111251877Speter 112251877Speter inline bool index_is_valid(int idx) { 113251877Speter return idx >= 0 && (unsigned) idx < Term->getNumSuccessors(); 114251877Speter } 115251877Speter 116251877Speterpublic: 117251877Speter typedef typename super::pointer pointer; 118251877Speter typedef typename super::reference reference; 119251877Speter // TODO: This can be random access iterator, only operator[] missing. 120251877Speter 121251877Speter explicit inline SuccIterator(Term_ T) : Term(T), idx(0) {// begin iterator 122251877Speter } 123251877Speter inline SuccIterator(Term_ T, bool) // end iterator 124251877Speter : Term(T) { 125251877Speter if (Term) 126251877Speter idx = Term->getNumSuccessors(); 127251877Speter else 128251877Speter // Term == NULL happens, if a basic block is not fully constructed and 129251877Speter // consequently getTerminator() returns NULL. In this case we construct a 130251877Speter // SuccIterator which describes a basic block that has zero successors. 131251877Speter // Defining SuccIterator for incomplete and malformed CFGs is especially 132251877Speter // useful for debugging. 133251877Speter idx = 0; 134251877Speter } 135251877Speter 136251877Speter inline const Self &operator=(const Self &I) { 137251877Speter assert(Term == I.Term &&"Cannot assign iterators to two different blocks!"); 138251877Speter idx = I.idx; 139251877Speter return *this; 140251877Speter } 141251877Speter 142251877Speter /// getSuccessorIndex - This is used to interface between code that wants to 143251877Speter /// operate on terminator instructions directly. 144251877Speter unsigned getSuccessorIndex() const { return idx; } 145251877Speter 146251877Speter inline bool operator==(const Self& x) const { return idx == x.idx; } 147251877Speter inline bool operator!=(const Self& x) const { return !operator==(x); } 148251877Speter 149251877Speter inline reference operator*() const { return Term->getSuccessor(idx); } 150251877Speter inline pointer operator->() const { return operator*(); } 151253895Speter 152253895Speter inline Self& operator++() { ++idx; return *this; } // Preincrement 153253895Speter 154253895Speter inline Self operator++(int) { // Postincrement 155253895Speter Self tmp = *this; ++*this; return tmp; 156253895Speter } 157253895Speter 158253895Speter inline Self& operator--() { --idx; return *this; } // Predecrement 159251877Speter inline Self operator--(int) { // Postdecrement 160251877Speter Self tmp = *this; --*this; return tmp; 161251877Speter } 162251877Speter 163251877Speter inline bool operator<(const Self& x) const { 164251877Speter assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 165251877Speter return idx < x.idx; 166251877Speter } 167251877Speter 168251877Speter inline bool operator<=(const Self& x) const { 169251877Speter assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 170251877Speter return idx <= x.idx; 171251877Speter } 172251877Speter inline bool operator>=(const Self& x) const { 173251877Speter assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 174251877Speter return idx >= x.idx; 175251877Speter } 176251877Speter 177251877Speter inline bool operator>(const Self& x) const { 178251877Speter assert(Term == x.Term && "Cannot compare iterators of different blocks!"); 179251877Speter return idx > x.idx; 180251877Speter } 181251877Speter 182251877Speter inline Self& operator+=(int Right) { 183251877Speter unsigned new_idx = idx + Right; 184251877Speter assert(index_is_valid(new_idx) && "Iterator index out of bound"); 185251877Speter idx = new_idx; 186251877Speter return *this; 187251877Speter } 188251877Speter 189251877Speter inline Self operator+(int Right) { 190251877Speter Self tmp = *this; 191251877Speter tmp += Right; 192251877Speter return tmp; 193251877Speter } 194251877Speter 195251877Speter inline Self& operator-=(int Right) { 196251877Speter return operator+=(-Right); 197251877Speter } 198251877Speter 199251877Speter inline Self operator-(int Right) { 200251877Speter return operator+(-Right); 201251877Speter } 202251877Speter 203251877Speter inline int operator-(const Self& x) { 204251877Speter assert(Term == x.Term && "Cannot work on iterators of different blocks!"); 205251877Speter int distance = idx - x.idx; 206251877Speter return distance; 207251877Speter } 208251877Speter 209251877Speter // This works for read access, however write access is difficult as changes 210251877Speter // to Term are only possible with Term->setSuccessor(idx). Pointers that can 211251877Speter // be modified are not available. 212251877Speter // 213251877Speter // inline pointer operator[](int offset) { 214251877Speter // Self tmp = *this; 215251877Speter // tmp += offset; 216251877Speter // return tmp.operator*(); 217251877Speter // } 218251877Speter 219251877Speter /// Get the source BB of this iterator. 220251877Speter inline BB_ *getSource() { 221251877Speter assert(Term && "Source not available, if basic block was malformed"); 222251877Speter return Term->getParent(); 223251877Speter } 224251877Speter}; 225251877Speter 226251877Spetertypedef SuccIterator<TerminatorInst*, BasicBlock> succ_iterator; 227251877Spetertypedef SuccIterator<const TerminatorInst*, 228251877Speter const BasicBlock> succ_const_iterator; 229251877Speter 230251877Speterinline succ_iterator succ_begin(BasicBlock *BB) { 231251877Speter return succ_iterator(BB->getTerminator()); 232251877Speter} 233251877Speterinline succ_const_iterator succ_begin(const BasicBlock *BB) { 234251877Speter return succ_const_iterator(BB->getTerminator()); 235251877Speter} 236251877Speterinline succ_iterator succ_end(BasicBlock *BB) { 237251877Speter return succ_iterator(BB->getTerminator(), true); 238251877Speter} 239251877Speterinline succ_const_iterator succ_end(const BasicBlock *BB) { 240251877Speter return succ_const_iterator(BB->getTerminator(), true); 241251877Speter} 242251877Speter 243251877Spetertemplate <typename T, typename U> struct isPodLike<SuccIterator<T, U> > { 244251877Speter static const bool value = isPodLike<T>::value; 245251877Speter}; 246251877Speter 247251877Speter 248251877Speter 249251877Speter//===--------------------------------------------------------------------===// 250251877Speter// GraphTraits specializations for basic block graphs (CFGs) 251251877Speter//===--------------------------------------------------------------------===// 252251877Speter 253251877Speter// Provide specializations of GraphTraits to be able to treat a function as a 254251877Speter// graph of basic blocks... 255251877Speter 256251877Spetertemplate <> struct GraphTraits<BasicBlock*> { 257251877Speter typedef BasicBlock NodeType; 258251877Speter typedef succ_iterator ChildIteratorType; 259251877Speter 260251877Speter static NodeType *getEntryNode(BasicBlock *BB) { return BB; } 261251877Speter static inline ChildIteratorType child_begin(NodeType *N) { 262251877Speter return succ_begin(N); 263251877Speter } 264251877Speter static inline ChildIteratorType child_end(NodeType *N) { 265251877Speter return succ_end(N); 266251877Speter } 267251877Speter}; 268251877Speter 269251877Spetertemplate <> struct GraphTraits<const BasicBlock*> { 270251877Speter typedef const BasicBlock NodeType; 271251877Speter typedef succ_const_iterator ChildIteratorType; 272251877Speter 273251877Speter static NodeType *getEntryNode(const BasicBlock *BB) { return BB; } 274251877Speter 275251877Speter static inline ChildIteratorType child_begin(NodeType *N) { 276251877Speter return succ_begin(N); 277251877Speter } 278251877Speter static inline ChildIteratorType child_end(NodeType *N) { 279251877Speter return succ_end(N); 280251877Speter } 281251877Speter}; 282251877Speter 283251877Speter// Provide specializations of GraphTraits to be able to treat a function as a 284251877Speter// graph of basic blocks... and to walk it in inverse order. Inverse order for 285251877Speter// a function is considered to be when traversing the predecessor edges of a BB 286251877Speter// instead of the successor edges. 287251877Speter// 288251877Spetertemplate <> struct GraphTraits<Inverse<BasicBlock*> > { 289251877Speter typedef BasicBlock NodeType; 290251877Speter typedef pred_iterator ChildIteratorType; 291251877Speter static NodeType *getEntryNode(Inverse<BasicBlock *> G) { return G.Graph; } 292251877Speter static inline ChildIteratorType child_begin(NodeType *N) { 293251877Speter return pred_begin(N); 294251877Speter } 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