1 //===- CFG.h - Process LLVM structures as graphs ----------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines specializations of GraphTraits that allow Function and
11 // BasicBlock graphs to be treated as proper graphs for generic algorithms.
13 //===----------------------------------------------------------------------===//
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"
25 //===----------------------------------------------------------------------===//
26 // BasicBlock pred_iterator definition
27 //===----------------------------------------------------------------------===//
29 template <class Ptr, class USE_iterator> // Predecessor Iterator
30 class 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*,
34 typedef PredIterator<Ptr, USE_iterator> Self;
37 inline void advancePastNonTerminators() {
38 // Loop to ignore non-terminator uses (for example BlockAddresses).
39 while (!It.atEnd() && !isa<TerminatorInst>(*It))
44 typedef typename super::pointer pointer;
45 typedef typename super::reference reference;
48 explicit inline PredIterator(Ptr *bb) : It(bb->user_begin()) {
49 advancePastNonTerminators();
51 inline PredIterator(Ptr *bb, bool) : It(bb->user_end()) {}
53 inline bool operator==(const Self& x) const { return It == x.It; }
54 inline bool operator!=(const Self& x) const { return !operator==(x); }
56 inline reference operator*() const {
57 assert(!It.atEnd() && "pred_iterator out of range!");
58 return cast<TerminatorInst>(*It)->getParent();
60 inline pointer *operator->() const { return &operator*(); }
62 inline Self& operator++() { // Preincrement
63 assert(!It.atEnd() && "pred_iterator out of range!");
64 ++It; advancePastNonTerminators();
68 inline Self operator++(int) { // Postincrement
69 Self tmp = *this; ++*this; return tmp;
72 /// getOperandNo - Return the operand number in the predecessor's
73 /// terminator of the successor.
74 unsigned getOperandNo() const {
75 return It.getOperandNo();
78 /// getUse - Return the operand Use in the predecessor's terminator
85 typedef PredIterator<BasicBlock, Value::user_iterator> pred_iterator;
86 typedef PredIterator<const BasicBlock,
87 Value::const_user_iterator> const_pred_iterator;
88 typedef llvm::iterator_range<pred_iterator> pred_range;
89 typedef llvm::iterator_range<const_pred_iterator> pred_const_range;
91 inline pred_iterator pred_begin(BasicBlock *BB) { return pred_iterator(BB); }
92 inline const_pred_iterator pred_begin(const BasicBlock *BB) {
93 return const_pred_iterator(BB);
95 inline pred_iterator pred_end(BasicBlock *BB) { return pred_iterator(BB, true);}
96 inline const_pred_iterator pred_end(const BasicBlock *BB) {
97 return const_pred_iterator(BB, true);
99 inline bool pred_empty(const BasicBlock *BB) {
100 return pred_begin(BB) == pred_end(BB);
102 inline pred_range predecessors(BasicBlock *BB) {
103 return pred_range(pred_begin(BB), pred_end(BB));
105 inline pred_const_range predecessors(const BasicBlock *BB) {
106 return pred_const_range(pred_begin(BB), pred_end(BB));
109 //===----------------------------------------------------------------------===//
110 // BasicBlock succ_iterator definition
111 //===----------------------------------------------------------------------===//
113 template <class Term_, class BB_> // Successor Iterator
114 class SuccIterator : public std::iterator<std::random_access_iterator_tag, BB_,
116 typedef std::iterator<std::random_access_iterator_tag, BB_, int, BB_ *, BB_ *>
120 typedef typename super::pointer pointer;
121 typedef typename super::reference reference;
126 typedef SuccIterator<Term_, BB_> Self;
128 inline bool index_is_valid(int idx) {
129 return idx >= 0 && (unsigned) idx < Term->getNumSuccessors();
132 /// \brief Proxy object to allow write access in operator[]
133 class SuccessorProxy {
137 explicit SuccessorProxy(const Self &it) : it(it) {}
139 SuccessorProxy(const SuccessorProxy&) = default;
141 SuccessorProxy &operator=(SuccessorProxy r) {
142 *this = reference(r);
146 SuccessorProxy &operator=(reference r) {
147 it.Term->setSuccessor(it.idx, r);
151 operator reference() const { return *it; }
155 explicit inline SuccIterator(Term_ T) : Term(T), idx(0) {// begin iterator
157 inline SuccIterator(Term_ T, bool) // end iterator
160 idx = Term->getNumSuccessors();
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.
170 inline const Self &operator=(const Self &I) {
171 assert(Term == I.Term &&"Cannot assign iterators to two different blocks!");
176 /// getSuccessorIndex - This is used to interface between code that wants to
177 /// operate on terminator instructions directly.
178 unsigned getSuccessorIndex() const { return idx; }
180 inline bool operator==(const Self& x) const { return idx == x.idx; }
181 inline bool operator!=(const Self& x) const { return !operator==(x); }
183 inline reference operator*() const { return Term->getSuccessor(idx); }
184 inline pointer operator->() const { return operator*(); }
186 inline Self& operator++() { ++idx; return *this; } // Preincrement
188 inline Self operator++(int) { // Postincrement
189 Self tmp = *this; ++*this; return tmp;
192 inline Self& operator--() { --idx; return *this; } // Predecrement
193 inline Self operator--(int) { // Postdecrement
194 Self tmp = *this; --*this; return tmp;
197 inline bool operator<(const Self& x) const {
198 assert(Term == x.Term && "Cannot compare iterators of different blocks!");
202 inline bool operator<=(const Self& x) const {
203 assert(Term == x.Term && "Cannot compare iterators of different blocks!");
206 inline bool operator>=(const Self& x) const {
207 assert(Term == x.Term && "Cannot compare iterators of different blocks!");
211 inline bool operator>(const Self& x) const {
212 assert(Term == x.Term && "Cannot compare iterators of different blocks!");
216 inline Self& operator+=(int Right) {
217 unsigned new_idx = idx + Right;
218 assert(index_is_valid(new_idx) && "Iterator index out of bound");
223 inline Self operator+(int Right) const {
229 inline Self& operator-=(int Right) {
230 return operator+=(-Right);
233 inline Self operator-(int Right) const {
234 return operator+(-Right);
237 inline int operator-(const Self& x) const {
238 assert(Term == x.Term && "Cannot work on iterators of different blocks!");
239 int distance = idx - x.idx;
243 inline SuccessorProxy operator[](int offset) {
246 return SuccessorProxy(tmp);
249 /// Get the source BB of this iterator.
250 inline BB_ *getSource() {
251 assert(Term && "Source not available, if basic block was malformed");
252 return Term->getParent();
256 typedef SuccIterator<TerminatorInst*, BasicBlock> succ_iterator;
257 typedef SuccIterator<const TerminatorInst*,
258 const BasicBlock> succ_const_iterator;
259 typedef llvm::iterator_range<succ_iterator> succ_range;
260 typedef llvm::iterator_range<succ_const_iterator> succ_const_range;
262 inline succ_iterator succ_begin(BasicBlock *BB) {
263 return succ_iterator(BB->getTerminator());
265 inline succ_const_iterator succ_begin(const BasicBlock *BB) {
266 return succ_const_iterator(BB->getTerminator());
268 inline succ_iterator succ_end(BasicBlock *BB) {
269 return succ_iterator(BB->getTerminator(), true);
271 inline succ_const_iterator succ_end(const BasicBlock *BB) {
272 return succ_const_iterator(BB->getTerminator(), true);
274 inline bool succ_empty(const BasicBlock *BB) {
275 return succ_begin(BB) == succ_end(BB);
277 inline succ_range successors(BasicBlock *BB) {
278 return succ_range(succ_begin(BB), succ_end(BB));
280 inline succ_const_range successors(const BasicBlock *BB) {
281 return succ_const_range(succ_begin(BB), succ_end(BB));
285 template <typename T, typename U> struct isPodLike<SuccIterator<T, U> > {
286 static const bool value = isPodLike<T>::value;
291 //===--------------------------------------------------------------------===//
292 // GraphTraits specializations for basic block graphs (CFGs)
293 //===--------------------------------------------------------------------===//
295 // Provide specializations of GraphTraits to be able to treat a function as a
296 // graph of basic blocks...
298 template <> struct GraphTraits<BasicBlock*> {
299 typedef BasicBlock NodeType;
300 typedef succ_iterator ChildIteratorType;
302 static NodeType *getEntryNode(BasicBlock *BB) { return BB; }
303 static inline ChildIteratorType child_begin(NodeType *N) {
304 return succ_begin(N);
306 static inline ChildIteratorType child_end(NodeType *N) {
311 template <> struct GraphTraits<const BasicBlock*> {
312 typedef const BasicBlock NodeType;
313 typedef succ_const_iterator ChildIteratorType;
315 static NodeType *getEntryNode(const BasicBlock *BB) { return BB; }
317 static inline ChildIteratorType child_begin(NodeType *N) {
318 return succ_begin(N);
320 static inline ChildIteratorType child_end(NodeType *N) {
325 // Provide specializations of GraphTraits to be able to treat a function as a
326 // graph of basic blocks... and to walk it in inverse order. Inverse order for
327 // a function is considered to be when traversing the predecessor edges of a BB
328 // instead of the successor edges.
330 template <> struct GraphTraits<Inverse<BasicBlock*> > {
331 typedef BasicBlock NodeType;
332 typedef pred_iterator ChildIteratorType;
333 static NodeType *getEntryNode(Inverse<BasicBlock *> G) { return G.Graph; }
334 static inline ChildIteratorType child_begin(NodeType *N) {
335 return pred_begin(N);
337 static inline ChildIteratorType child_end(NodeType *N) {
342 template <> struct GraphTraits<Inverse<const BasicBlock*> > {
343 typedef const BasicBlock NodeType;
344 typedef const_pred_iterator ChildIteratorType;
345 static NodeType *getEntryNode(Inverse<const BasicBlock*> G) {
348 static inline ChildIteratorType child_begin(NodeType *N) {
349 return pred_begin(N);
351 static inline ChildIteratorType child_end(NodeType *N) {
358 //===--------------------------------------------------------------------===//
359 // GraphTraits specializations for function basic block graphs (CFGs)
360 //===--------------------------------------------------------------------===//
362 // Provide specializations of GraphTraits to be able to treat a function as a
363 // graph of basic blocks... these are the same as the basic block iterators,
364 // except that the root node is implicitly the first node of the function.
366 template <> struct GraphTraits<Function*> : public GraphTraits<BasicBlock*> {
367 static NodeType *getEntryNode(Function *F) { return &F->getEntryBlock(); }
369 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
370 typedef Function::iterator nodes_iterator;
371 static nodes_iterator nodes_begin(Function *F) { return F->begin(); }
372 static nodes_iterator nodes_end (Function *F) { return F->end(); }
373 static size_t size (Function *F) { return F->size(); }
375 template <> struct GraphTraits<const Function*> :
376 public GraphTraits<const BasicBlock*> {
377 static NodeType *getEntryNode(const Function *F) {return &F->getEntryBlock();}
379 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
380 typedef Function::const_iterator nodes_iterator;
381 static nodes_iterator nodes_begin(const Function *F) { return F->begin(); }
382 static nodes_iterator nodes_end (const Function *F) { return F->end(); }
383 static size_t size (const Function *F) { return F->size(); }
387 // Provide specializations of GraphTraits to be able to treat a function as a
388 // graph of basic blocks... and to walk it in inverse order. Inverse order for
389 // a function is considered to be when traversing the predecessor edges of a BB
390 // instead of the successor edges.
392 template <> struct GraphTraits<Inverse<Function*> > :
393 public GraphTraits<Inverse<BasicBlock*> > {
394 static NodeType *getEntryNode(Inverse<Function*> G) {
395 return &G.Graph->getEntryBlock();
398 template <> struct GraphTraits<Inverse<const Function*> > :
399 public GraphTraits<Inverse<const BasicBlock*> > {
400 static NodeType *getEntryNode(Inverse<const Function *> G) {
401 return &G.Graph->getEntryBlock();
405 } // End llvm namespace