1 //===-- llvm/Support/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 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_SUPPORT_CFG_H
16 #define LLVM_SUPPORT_CFG_H
18 #include "llvm/ADT/GraphTraits.h"
19 #include "llvm/Function.h"
20 #include "llvm/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,
31 typedef std::iterator<std::forward_iterator_tag, _Ptr, ptrdiff_t> super;
34 typedef PredIterator<_Ptr,_USE_iterator> _Self;
35 typedef typename super::pointer pointer;
37 inline void advancePastNonTerminators() {
38 // Loop to ignore non terminator uses (for example PHI nodes)...
39 while (!It.atEnd() && !isa<TerminatorInst>(*It))
43 inline PredIterator(_Ptr *bb) : It(bb->use_begin()) {
44 advancePastNonTerminators();
46 inline PredIterator(_Ptr *bb, bool) : It(bb->use_end()) {}
48 inline bool operator==(const _Self& x) const { return It == x.It; }
49 inline bool operator!=(const _Self& x) const { return !operator==(x); }
51 inline pointer operator*() const {
52 assert(!It.atEnd() && "pred_iterator out of range!");
53 return cast<TerminatorInst>(*It)->getParent();
55 inline pointer *operator->() const { return &(operator*()); }
57 inline _Self& operator++() { // Preincrement
58 assert(!It.atEnd() && "pred_iterator out of range!");
59 ++It; advancePastNonTerminators();
63 inline _Self operator++(int) { // Postincrement
64 _Self tmp = *this; ++*this; return tmp;
68 typedef PredIterator<BasicBlock, Value::use_iterator> pred_iterator;
69 typedef PredIterator<const BasicBlock,
70 Value::const_use_iterator> pred_const_iterator;
72 inline pred_iterator pred_begin(BasicBlock *BB) { return pred_iterator(BB); }
73 inline pred_const_iterator pred_begin(const BasicBlock *BB) {
74 return pred_const_iterator(BB);
76 inline pred_iterator pred_end(BasicBlock *BB) { return pred_iterator(BB, true);}
77 inline pred_const_iterator pred_end(const BasicBlock *BB) {
78 return pred_const_iterator(BB, true);
83 //===----------------------------------------------------------------------===//
84 // BasicBlock succ_iterator definition
85 //===----------------------------------------------------------------------===//
87 template <class Term_, class BB_> // Successor Iterator
88 class SuccIterator : public std::iterator<std::bidirectional_iterator_tag,
92 typedef std::iterator<std::bidirectional_iterator_tag, BB_, ptrdiff_t> super;
94 typedef SuccIterator<Term_, BB_> _Self;
95 typedef typename super::pointer pointer;
96 // TODO: This can be random access iterator, only operator[] missing.
98 inline SuccIterator(Term_ T) : Term(T), idx(0) { // begin iterator
99 assert(T && "getTerminator returned null!");
101 inline SuccIterator(Term_ T, bool) // end iterator
102 : Term(T), idx(Term->getNumSuccessors()) {
103 assert(T && "getTerminator returned null!");
106 inline const _Self &operator=(const _Self &I) {
107 assert(Term == I.Term &&"Cannot assign iterators to two different blocks!");
112 inline bool index_is_valid (int idx) {
113 return idx >= 0 && (unsigned) idx < Term->getNumSuccessors();
116 /// getSuccessorIndex - This is used to interface between code that wants to
117 /// operate on terminator instructions directly.
118 unsigned getSuccessorIndex() const { return idx; }
120 inline bool operator==(const _Self& x) const { return idx == x.idx; }
121 inline bool operator!=(const _Self& x) const { return !operator==(x); }
123 inline pointer operator*() const { return Term->getSuccessor(idx); }
124 inline pointer operator->() const { return operator*(); }
126 inline _Self& operator++() { ++idx; return *this; } // Preincrement
128 inline _Self operator++(int) { // Postincrement
129 _Self tmp = *this; ++*this; return tmp;
132 inline _Self& operator--() { --idx; return *this; } // Predecrement
133 inline _Self operator--(int) { // Postdecrement
134 _Self tmp = *this; --*this; return tmp;
137 inline bool operator<(const _Self& x) const {
138 assert(Term == x.Term && "Cannot compare iterators of different blocks!");
142 inline bool operator<=(const _Self& x) const {
143 assert(Term == x.Term && "Cannot compare iterators of different blocks!");
146 inline bool operator>=(const _Self& x) const {
147 assert(Term == x.Term && "Cannot compare iterators of different blocks!");
151 inline bool operator>(const _Self& x) const {
152 assert(Term == x.Term && "Cannot compare iterators of different blocks!");
156 inline _Self& operator+=(int Right) {
157 unsigned new_idx = idx + Right;
158 assert(index_is_valid(new_idx) && "Iterator index out of bound");
163 inline _Self operator+(int Right) {
169 inline _Self& operator-=(int Right) {
170 return operator+=(-Right);
173 inline _Self operator-(int Right) {
174 return operator+(-Right);
177 inline int operator-(const _Self& x) {
178 assert(Term == x.Term && "Cannot work on iterators of different blocks!");
179 int distance = idx - x.idx;
183 // This works for read access, however write access is difficult as changes
184 // to Term are only possible with Term->setSuccessor(idx). Pointers that can
185 // be modified are not available.
187 // inline pointer operator[](int offset) {
188 // _Self tmp = *this;
190 // return tmp.operator*();
193 /// Get the source BB of this iterator.
194 inline BB_ *getSource() {
195 return Term->getParent();
199 typedef SuccIterator<TerminatorInst*, BasicBlock> succ_iterator;
200 typedef SuccIterator<const TerminatorInst*,
201 const BasicBlock> succ_const_iterator;
203 inline succ_iterator succ_begin(BasicBlock *BB) {
204 return succ_iterator(BB->getTerminator());
206 inline succ_const_iterator succ_begin(const BasicBlock *BB) {
207 return succ_const_iterator(BB->getTerminator());
209 inline succ_iterator succ_end(BasicBlock *BB) {
210 return succ_iterator(BB->getTerminator(), true);
212 inline succ_const_iterator succ_end(const BasicBlock *BB) {
213 return succ_const_iterator(BB->getTerminator(), true);
218 //===--------------------------------------------------------------------===//
219 // GraphTraits specializations for basic block graphs (CFGs)
220 //===--------------------------------------------------------------------===//
222 // Provide specializations of GraphTraits to be able to treat a function as a
223 // graph of basic blocks...
225 template <> struct GraphTraits<BasicBlock*> {
226 typedef BasicBlock NodeType;
227 typedef succ_iterator ChildIteratorType;
229 static NodeType *getEntryNode(BasicBlock *BB) { return BB; }
230 static inline ChildIteratorType child_begin(NodeType *N) {
231 return succ_begin(N);
233 static inline ChildIteratorType child_end(NodeType *N) {
238 template <> struct GraphTraits<const BasicBlock*> {
239 typedef const BasicBlock NodeType;
240 typedef succ_const_iterator ChildIteratorType;
242 static NodeType *getEntryNode(const BasicBlock *BB) { return BB; }
244 static inline ChildIteratorType child_begin(NodeType *N) {
245 return succ_begin(N);
247 static inline ChildIteratorType child_end(NodeType *N) {
252 // Provide specializations of GraphTraits to be able to treat a function as a
253 // graph of basic blocks... and to walk it in inverse order. Inverse order for
254 // a function is considered to be when traversing the predecessor edges of a BB
255 // instead of the successor edges.
257 template <> struct GraphTraits<Inverse<BasicBlock*> > {
258 typedef BasicBlock NodeType;
259 typedef pred_iterator ChildIteratorType;
260 static NodeType *getEntryNode(Inverse<BasicBlock *> G) { return G.Graph; }
261 static inline ChildIteratorType child_begin(NodeType *N) {
262 return pred_begin(N);
264 static inline ChildIteratorType child_end(NodeType *N) {
269 template <> struct GraphTraits<Inverse<const BasicBlock*> > {
270 typedef const BasicBlock NodeType;
271 typedef pred_const_iterator ChildIteratorType;
272 static NodeType *getEntryNode(Inverse<const BasicBlock*> G) {
275 static inline ChildIteratorType child_begin(NodeType *N) {
276 return pred_begin(N);
278 static inline ChildIteratorType child_end(NodeType *N) {
285 //===--------------------------------------------------------------------===//
286 // GraphTraits specializations for function basic block graphs (CFGs)
287 //===--------------------------------------------------------------------===//
289 // Provide specializations of GraphTraits to be able to treat a function as a
290 // graph of basic blocks... these are the same as the basic block iterators,
291 // except that the root node is implicitly the first node of the function.
293 template <> struct GraphTraits<Function*> : public GraphTraits<BasicBlock*> {
294 static NodeType *getEntryNode(Function *F) { return &F->getEntryBlock(); }
296 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
297 typedef Function::iterator nodes_iterator;
298 static nodes_iterator nodes_begin(Function *F) { return F->begin(); }
299 static nodes_iterator nodes_end (Function *F) { return F->end(); }
301 template <> struct GraphTraits<const Function*> :
302 public GraphTraits<const BasicBlock*> {
303 static NodeType *getEntryNode(const Function *F) {return &F->getEntryBlock();}
305 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
306 typedef Function::const_iterator nodes_iterator;
307 static nodes_iterator nodes_begin(const Function *F) { return F->begin(); }
308 static nodes_iterator nodes_end (const Function *F) { return F->end(); }
312 // Provide specializations of GraphTraits to be able to treat a function as a
313 // graph of basic blocks... and to walk it in inverse order. Inverse order for
314 // a function is considered to be when traversing the predecessor edges of a BB
315 // instead of the successor edges.
317 template <> struct GraphTraits<Inverse<Function*> > :
318 public GraphTraits<Inverse<BasicBlock*> > {
319 static NodeType *getEntryNode(Inverse<Function*> G) {
320 return &G.Graph->getEntryBlock();
323 template <> struct GraphTraits<Inverse<const Function*> > :
324 public GraphTraits<Inverse<const BasicBlock*> > {
325 static NodeType *getEntryNode(Inverse<const Function *> G) {
326 return &G.Graph->getEntryBlock();
330 } // End llvm namespace