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/IR/Function.h"
20 #include "llvm/IR/InstrTypes.h"
24 //===----------------------------------------------------------------------===//
25 // BasicBlock pred_iterator definition
26 //===----------------------------------------------------------------------===//
28 template <class Ptr, class USE_iterator> // Predecessor Iterator
29 class 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*,
33 typedef PredIterator<Ptr, USE_iterator> Self;
36 inline void advancePastNonTerminators() {
37 // Loop to ignore non-terminator uses (for example BlockAddresses).
38 while (!It.atEnd() && !isa<TerminatorInst>(*It))
43 typedef typename super::pointer pointer;
44 typedef typename super::reference reference;
47 explicit inline PredIterator(Ptr *bb) : It(bb->user_begin()) {
48 advancePastNonTerminators();
50 inline PredIterator(Ptr *bb, bool) : It(bb->user_end()) {}
52 inline bool operator==(const Self& x) const { return It == x.It; }
53 inline bool operator!=(const Self& x) const { return !operator==(x); }
55 inline reference operator*() const {
56 assert(!It.atEnd() && "pred_iterator out of range!");
57 return cast<TerminatorInst>(*It)->getParent();
59 inline pointer *operator->() const { return &operator*(); }
61 inline Self& operator++() { // Preincrement
62 assert(!It.atEnd() && "pred_iterator out of range!");
63 ++It; advancePastNonTerminators();
67 inline Self operator++(int) { // Postincrement
68 Self tmp = *this; ++*this; return tmp;
71 /// getOperandNo - Return the operand number in the predecessor's
72 /// terminator of the successor.
73 unsigned getOperandNo() const {
74 return It.getOperandNo();
77 /// getUse - Return the operand Use in the predecessor's terminator
84 typedef PredIterator<BasicBlock, Value::user_iterator> pred_iterator;
85 typedef PredIterator<const BasicBlock,
86 Value::const_user_iterator> const_pred_iterator;
88 inline pred_iterator pred_begin(BasicBlock *BB) { return pred_iterator(BB); }
89 inline const_pred_iterator pred_begin(const BasicBlock *BB) {
90 return const_pred_iterator(BB);
92 inline pred_iterator pred_end(BasicBlock *BB) { return pred_iterator(BB, true);}
93 inline const_pred_iterator pred_end(const BasicBlock *BB) {
94 return const_pred_iterator(BB, true);
96 inline iterator_range<pred_iterator> predecessors(BasicBlock *BB) {
97 return make_range(pred_begin(BB), pred_end(BB));
99 inline iterator_range<const_pred_iterator> predecessors(const BasicBlock *BB) {
100 return make_range(pred_begin(BB), pred_end(BB));
105 //===----------------------------------------------------------------------===//
106 // BasicBlock succ_iterator definition
107 //===----------------------------------------------------------------------===//
109 template <class Term_, class BB_> // Successor Iterator
110 class SuccIterator : public std::iterator<std::random_access_iterator_tag, BB_,
112 typedef std::iterator<std::random_access_iterator_tag, BB_, int, BB_ *, BB_ *>
116 typedef typename super::pointer pointer;
117 typedef typename super::reference reference;
122 typedef SuccIterator<Term_, BB_> Self;
124 inline bool index_is_valid(int idx) {
125 return idx >= 0 && (unsigned) idx < Term->getNumSuccessors();
128 /// \brief Proxy object to allow write access in operator[]
129 class SuccessorProxy {
133 explicit SuccessorProxy(const Self &it) : it(it) {}
135 SuccessorProxy &operator=(SuccessorProxy r) {
136 *this = reference(r);
140 SuccessorProxy &operator=(reference r) {
141 it.Term->setSuccessor(it.idx, r);
145 operator reference() const { return *it; }
149 explicit inline SuccIterator(Term_ T) : Term(T), idx(0) {// begin iterator
151 inline SuccIterator(Term_ T, bool) // end iterator
154 idx = Term->getNumSuccessors();
156 // Term == NULL happens, if a basic block is not fully constructed and
157 // consequently getTerminator() returns NULL. In this case we construct a
158 // SuccIterator which describes a basic block that has zero successors.
159 // Defining SuccIterator for incomplete and malformed CFGs is especially
160 // useful for debugging.
164 inline const Self &operator=(const Self &I) {
165 assert(Term == I.Term &&"Cannot assign iterators to two different blocks!");
170 /// getSuccessorIndex - This is used to interface between code that wants to
171 /// operate on terminator instructions directly.
172 unsigned getSuccessorIndex() const { return idx; }
174 inline bool operator==(const Self& x) const { return idx == x.idx; }
175 inline bool operator!=(const Self& x) const { return !operator==(x); }
177 inline reference operator*() const { return Term->getSuccessor(idx); }
178 inline pointer operator->() const { return operator*(); }
180 inline Self& operator++() { ++idx; return *this; } // Preincrement
182 inline Self operator++(int) { // Postincrement
183 Self tmp = *this; ++*this; return tmp;
186 inline Self& operator--() { --idx; return *this; } // Predecrement
187 inline Self operator--(int) { // Postdecrement
188 Self tmp = *this; --*this; return tmp;
191 inline bool operator<(const Self& x) const {
192 assert(Term == x.Term && "Cannot compare iterators of different blocks!");
196 inline bool operator<=(const Self& x) const {
197 assert(Term == x.Term && "Cannot compare iterators of different blocks!");
200 inline bool operator>=(const Self& x) const {
201 assert(Term == x.Term && "Cannot compare iterators of different blocks!");
205 inline bool operator>(const Self& x) const {
206 assert(Term == x.Term && "Cannot compare iterators of different blocks!");
210 inline Self& operator+=(int Right) {
211 unsigned new_idx = idx + Right;
212 assert(index_is_valid(new_idx) && "Iterator index out of bound");
217 inline Self operator+(int Right) const {
223 inline Self& operator-=(int Right) {
224 return operator+=(-Right);
227 inline Self operator-(int Right) const {
228 return operator+(-Right);
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;
237 inline SuccessorProxy operator[](int offset) {
240 return SuccessorProxy(tmp);
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();
250 typedef SuccIterator<TerminatorInst*, BasicBlock> succ_iterator;
251 typedef SuccIterator<const TerminatorInst*,
252 const BasicBlock> succ_const_iterator;
254 inline succ_iterator succ_begin(BasicBlock *BB) {
255 return succ_iterator(BB->getTerminator());
257 inline succ_const_iterator succ_begin(const BasicBlock *BB) {
258 return succ_const_iterator(BB->getTerminator());
260 inline succ_iterator succ_end(BasicBlock *BB) {
261 return succ_iterator(BB->getTerminator(), true);
263 inline succ_const_iterator succ_end(const BasicBlock *BB) {
264 return succ_const_iterator(BB->getTerminator(), true);
266 inline iterator_range<succ_iterator> successors(BasicBlock *BB) {
267 return make_range(succ_begin(BB), succ_end(BB));
269 inline iterator_range<succ_const_iterator> successors(const BasicBlock *BB) {
270 return make_range(succ_begin(BB), succ_end(BB));
273 template <typename T, typename U> struct isPodLike<SuccIterator<T, U> > {
274 static const bool value = isPodLike<T>::value;
279 //===--------------------------------------------------------------------===//
280 // GraphTraits specializations for basic block graphs (CFGs)
281 //===--------------------------------------------------------------------===//
283 // Provide specializations of GraphTraits to be able to treat a function as a
284 // graph of basic blocks...
286 template <> struct GraphTraits<BasicBlock*> {
287 typedef BasicBlock NodeType;
288 typedef succ_iterator ChildIteratorType;
290 static NodeType *getEntryNode(BasicBlock *BB) { return BB; }
291 static inline ChildIteratorType child_begin(NodeType *N) {
292 return succ_begin(N);
294 static inline ChildIteratorType child_end(NodeType *N) {
299 template <> struct GraphTraits<const BasicBlock*> {
300 typedef const BasicBlock NodeType;
301 typedef succ_const_iterator ChildIteratorType;
303 static NodeType *getEntryNode(const BasicBlock *BB) { return BB; }
305 static inline ChildIteratorType child_begin(NodeType *N) {
306 return succ_begin(N);
308 static inline ChildIteratorType child_end(NodeType *N) {
313 // Provide specializations of GraphTraits to be able to treat a function as a
314 // graph of basic blocks... and to walk it in inverse order. Inverse order for
315 // a function is considered to be when traversing the predecessor edges of a BB
316 // instead of the successor edges.
318 template <> struct GraphTraits<Inverse<BasicBlock*> > {
319 typedef BasicBlock NodeType;
320 typedef pred_iterator ChildIteratorType;
321 static NodeType *getEntryNode(Inverse<BasicBlock *> G) { return G.Graph; }
322 static inline ChildIteratorType child_begin(NodeType *N) {
323 return pred_begin(N);
325 static inline ChildIteratorType child_end(NodeType *N) {
330 template <> struct GraphTraits<Inverse<const BasicBlock*> > {
331 typedef const BasicBlock NodeType;
332 typedef const_pred_iterator ChildIteratorType;
333 static NodeType *getEntryNode(Inverse<const BasicBlock*> G) {
336 static inline ChildIteratorType child_begin(NodeType *N) {
337 return pred_begin(N);
339 static inline ChildIteratorType child_end(NodeType *N) {
346 //===--------------------------------------------------------------------===//
347 // GraphTraits specializations for function basic block graphs (CFGs)
348 //===--------------------------------------------------------------------===//
350 // Provide specializations of GraphTraits to be able to treat a function as a
351 // graph of basic blocks... these are the same as the basic block iterators,
352 // except that the root node is implicitly the first node of the function.
354 template <> struct GraphTraits<Function*> : public GraphTraits<BasicBlock*> {
355 static NodeType *getEntryNode(Function *F) { return &F->getEntryBlock(); }
357 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
358 typedef Function::iterator nodes_iterator;
359 static nodes_iterator nodes_begin(Function *F) { return F->begin(); }
360 static nodes_iterator nodes_end (Function *F) { return F->end(); }
361 static size_t size (Function *F) { return F->size(); }
363 template <> struct GraphTraits<const Function*> :
364 public GraphTraits<const BasicBlock*> {
365 static NodeType *getEntryNode(const Function *F) {return &F->getEntryBlock();}
367 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
368 typedef Function::const_iterator nodes_iterator;
369 static nodes_iterator nodes_begin(const Function *F) { return F->begin(); }
370 static nodes_iterator nodes_end (const Function *F) { return F->end(); }
371 static size_t size (const Function *F) { return F->size(); }
375 // Provide specializations of GraphTraits to be able to treat a function as a
376 // graph of basic blocks... and to walk it in inverse order. Inverse order for
377 // a function is considered to be when traversing the predecessor edges of a BB
378 // instead of the successor edges.
380 template <> struct GraphTraits<Inverse<Function*> > :
381 public GraphTraits<Inverse<BasicBlock*> > {
382 static NodeType *getEntryNode(Inverse<Function*> G) {
383 return &G.Graph->getEntryBlock();
386 template <> struct GraphTraits<Inverse<const Function*> > :
387 public GraphTraits<Inverse<const BasicBlock*> > {
388 static NodeType *getEntryNode(Inverse<const Function *> G) {
389 return &G.Graph->getEntryBlock();
393 } // End llvm namespace