1 //===-- llvm/Support/CFG.h - Process LLVM structures as graphs --*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source 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"
21 #include "llvm/ADT/iterator"
25 //===--------------------------------------------------------------------===//
26 // BasicBlock pred_iterator definition
27 //===--------------------------------------------------------------------===//
29 template <class _Ptr, class _USE_iterator> // Predecessor Iterator
30 class PredIterator : public forward_iterator<_Ptr, ptrdiff_t> {
31 typedef forward_iterator<_Ptr, ptrdiff_t> super;
35 typedef PredIterator<_Ptr,_USE_iterator> _Self;
36 typedef typename super::pointer pointer;
38 inline void advancePastNonTerminators() {
39 // Loop to ignore non terminator uses (for example PHI nodes)...
40 while (It != BB->use_end() && !isa<TerminatorInst>(*It))
44 inline PredIterator(_Ptr *bb) : BB(bb), It(bb->use_begin()) {
45 advancePastNonTerminators();
47 inline PredIterator(_Ptr *bb, bool) : BB(bb), It(bb->use_end()) {}
49 inline bool operator==(const _Self& x) const { return It == x.It; }
50 inline bool operator!=(const _Self& x) const { return !operator==(x); }
52 inline pointer operator*() const {
53 assert(It != BB->use_end() && "pred_iterator out of range!");
54 return cast<TerminatorInst>(*It)->getParent();
56 inline pointer *operator->() const { return &(operator*()); }
58 inline _Self& operator++() { // Preincrement
59 assert(It != BB->use_end() && "pred_iterator out of range!");
60 ++It; advancePastNonTerminators();
64 inline _Self operator++(int) { // Postincrement
65 _Self tmp = *this; ++*this; return tmp;
69 typedef PredIterator<BasicBlock, Value::use_iterator> pred_iterator;
70 typedef PredIterator<const BasicBlock,
71 Value::use_const_iterator> pred_const_iterator;
73 inline pred_iterator pred_begin(BasicBlock *BB) { return pred_iterator(BB); }
74 inline pred_const_iterator pred_begin(const BasicBlock *BB) {
75 return pred_const_iterator(BB);
77 inline pred_iterator pred_end(BasicBlock *BB) { return pred_iterator(BB, true);}
78 inline pred_const_iterator pred_end(const BasicBlock *BB) {
79 return pred_const_iterator(BB, true);
84 //===--------------------------------------------------------------------===//
85 // BasicBlock succ_iterator definition
86 //===--------------------------------------------------------------------===//
88 template <class Term_, class BB_> // Successor Iterator
89 class SuccIterator : public bidirectional_iterator<BB_, ptrdiff_t> {
92 typedef bidirectional_iterator<BB_, ptrdiff_t> super;
94 typedef SuccIterator<Term_, BB_> _Self;
95 typedef typename super::pointer pointer;
96 // TODO: This can be random access iterator, need operator+ and stuff tho
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 /// getSuccessorIndex - This is used to interface between code that wants to
113 /// operate on terminator instructions directly.
114 unsigned getSuccessorIndex() const { return idx; }
116 inline bool operator==(const _Self& x) const { return idx == x.idx; }
117 inline bool operator!=(const _Self& x) const { return !operator==(x); }
119 inline pointer operator*() const { return Term->getSuccessor(idx); }
120 inline pointer operator->() const { return operator*(); }
122 inline _Self& operator++() { ++idx; return *this; } // Preincrement
123 inline _Self operator++(int) { // Postincrement
124 _Self tmp = *this; ++*this; return tmp;
127 inline _Self& operator--() { --idx; return *this; } // Predecrement
128 inline _Self operator--(int) { // Postdecrement
129 _Self tmp = *this; --*this; return tmp;
133 typedef SuccIterator<TerminatorInst*, BasicBlock> succ_iterator;
134 typedef SuccIterator<const TerminatorInst*,
135 const BasicBlock> succ_const_iterator;
137 inline succ_iterator succ_begin(BasicBlock *BB) {
138 return succ_iterator(BB->getTerminator());
140 inline succ_const_iterator succ_begin(const BasicBlock *BB) {
141 return succ_const_iterator(BB->getTerminator());
143 inline succ_iterator succ_end(BasicBlock *BB) {
144 return succ_iterator(BB->getTerminator(), true);
146 inline succ_const_iterator succ_end(const BasicBlock *BB) {
147 return succ_const_iterator(BB->getTerminator(), true);
152 //===--------------------------------------------------------------------===//
153 // GraphTraits specializations for basic block graphs (CFGs)
154 //===--------------------------------------------------------------------===//
156 // Provide specializations of GraphTraits to be able to treat a function as a
157 // graph of basic blocks...
159 template <> struct GraphTraits<BasicBlock*> {
160 typedef BasicBlock NodeType;
161 typedef succ_iterator ChildIteratorType;
163 static NodeType *getEntryNode(BasicBlock *BB) { return BB; }
164 static inline ChildIteratorType child_begin(NodeType *N) {
165 return succ_begin(N);
167 static inline ChildIteratorType child_end(NodeType *N) {
172 template <> struct GraphTraits<const BasicBlock*> {
173 typedef const BasicBlock NodeType;
174 typedef succ_const_iterator ChildIteratorType;
176 static NodeType *getEntryNode(const BasicBlock *BB) { return BB; }
178 static inline ChildIteratorType child_begin(NodeType *N) {
179 return succ_begin(N);
181 static inline ChildIteratorType child_end(NodeType *N) {
186 // Provide specializations of GraphTraits to be able to treat a function as a
187 // graph of basic blocks... and to walk it in inverse order. Inverse order for
188 // a function is considered to be when traversing the predecessor edges of a BB
189 // instead of the successor edges.
191 template <> struct GraphTraits<Inverse<BasicBlock*> > {
192 typedef BasicBlock NodeType;
193 typedef pred_iterator ChildIteratorType;
194 static NodeType *getEntryNode(Inverse<BasicBlock *> G) { return G.Graph; }
195 static inline ChildIteratorType child_begin(NodeType *N) {
196 return pred_begin(N);
198 static inline ChildIteratorType child_end(NodeType *N) {
203 template <> struct GraphTraits<Inverse<const BasicBlock*> > {
204 typedef const BasicBlock NodeType;
205 typedef pred_const_iterator ChildIteratorType;
206 static NodeType *getEntryNode(Inverse<const BasicBlock*> G) {
209 static inline ChildIteratorType child_begin(NodeType *N) {
210 return pred_begin(N);
212 static inline ChildIteratorType child_end(NodeType *N) {
219 //===--------------------------------------------------------------------===//
220 // GraphTraits specializations for function basic block graphs (CFGs)
221 //===--------------------------------------------------------------------===//
223 // Provide specializations of GraphTraits to be able to treat a function as a
224 // graph of basic blocks... these are the same as the basic block iterators,
225 // except that the root node is implicitly the first node of the function.
227 template <> struct GraphTraits<Function*> : public GraphTraits<BasicBlock*> {
228 static NodeType *getEntryNode(Function *F) { return &F->getEntryBlock(); }
230 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
231 typedef Function::iterator nodes_iterator;
232 static nodes_iterator nodes_begin(Function *F) { return F->begin(); }
233 static nodes_iterator nodes_end (Function *F) { return F->end(); }
235 template <> struct GraphTraits<const Function*> :
236 public GraphTraits<const BasicBlock*> {
237 static NodeType *getEntryNode(const Function *F) {return &F->getEntryBlock();}
239 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
240 typedef Function::const_iterator nodes_iterator;
241 static nodes_iterator nodes_begin(const Function *F) { return F->begin(); }
242 static nodes_iterator nodes_end (const Function *F) { return F->end(); }
246 // Provide specializations of GraphTraits to be able to treat a function as a
247 // graph of basic blocks... and to walk it in inverse order. Inverse order for
248 // a function is considered to be when traversing the predecessor edges of a BB
249 // instead of the successor edges.
251 template <> struct GraphTraits<Inverse<Function*> > :
252 public GraphTraits<Inverse<BasicBlock*> > {
253 static NodeType *getEntryNode(Inverse<Function*> G) {
254 return &G.Graph->getEntryBlock();
257 template <> struct GraphTraits<Inverse<const Function*> > :
258 public GraphTraits<Inverse<const BasicBlock*> > {
259 static NodeType *getEntryNode(Inverse<const Function *> G) {
260 return &G.Graph->getEntryBlock();
264 } // End llvm namespace