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 "Support/GraphTraits.h"
19 #include "llvm/Function.h"
20 #include "llvm/InstrTypes.h"
21 #include "Support/iterator"
23 //===--------------------------------------------------------------------===//
24 // BasicBlock pred_iterator definition
25 //===--------------------------------------------------------------------===//
27 template <class _Ptr, class _USE_iterator> // Predecessor Iterator
28 class PredIterator : public bidirectional_iterator<_Ptr, ptrdiff_t> {
29 typedef bidirectional_iterator<_Ptr, ptrdiff_t> super;
33 typedef PredIterator<_Ptr,_USE_iterator> _Self;
34 typedef typename super::pointer pointer;
36 inline void advancePastConstants() {
37 // Loop to ignore non terminator uses (for example PHI nodes)...
38 while (It != BB->use_end() && !isa<TerminatorInst>(*It))
42 inline PredIterator(_Ptr *bb) : BB(bb), It(bb->use_begin()) {
43 advancePastConstants();
45 inline PredIterator(_Ptr *bb, bool) : BB(bb), It(bb->use_end()) {}
47 inline bool operator==(const _Self& x) const { return It == x.It; }
48 inline bool operator!=(const _Self& x) const { return !operator==(x); }
50 inline pointer operator*() const {
51 assert(It != BB->use_end() && "pred_iterator out of range!");
52 return cast<TerminatorInst>(*It)->getParent();
54 inline pointer *operator->() const { return &(operator*()); }
56 inline _Self& operator++() { // Preincrement
57 assert(It != BB->use_end() && "pred_iterator out of range!");
58 ++It; advancePastConstants();
62 inline _Self operator++(int) { // Postincrement
63 _Self tmp = *this; ++*this; return tmp;
66 inline _Self& operator--() { --It; return *this; } // Predecrement
67 inline _Self operator--(int) { // Postdecrement
68 _Self tmp = *this; --*this; return tmp;
72 typedef PredIterator<BasicBlock, Value::use_iterator> pred_iterator;
73 typedef PredIterator<const BasicBlock,
74 Value::use_const_iterator> pred_const_iterator;
76 inline pred_iterator pred_begin(BasicBlock *BB) { return pred_iterator(BB); }
77 inline pred_const_iterator pred_begin(const BasicBlock *BB) {
78 return pred_const_iterator(BB);
80 inline pred_iterator pred_end(BasicBlock *BB) { return pred_iterator(BB, true);}
81 inline pred_const_iterator pred_end(const BasicBlock *BB) {
82 return pred_const_iterator(BB, true);
87 //===--------------------------------------------------------------------===//
88 // BasicBlock succ_iterator definition
89 //===--------------------------------------------------------------------===//
91 template <class _Term, class _BB> // Successor Iterator
92 class SuccIterator : public bidirectional_iterator<_BB, ptrdiff_t> {
95 typedef bidirectional_iterator<_BB, ptrdiff_t> super;
97 typedef SuccIterator<_Term, _BB> _Self;
98 typedef typename super::pointer pointer;
99 // TODO: This can be random access iterator, need operator+ and stuff tho
101 inline SuccIterator(_Term T) : Term(T), idx(0) { // begin iterator
102 assert(T && "getTerminator returned null!");
104 inline SuccIterator(_Term T, bool) // end iterator
105 : Term(T), idx(Term->getNumSuccessors()) {
106 assert(T && "getTerminator returned null!");
109 inline const _Self &operator=(const _Self &I) {
110 assert(Term == I.Term &&"Cannot assign iterators to two different blocks!");
115 /// getSuccessorIndex - This is used to interface between code that wants to
116 /// operate on terminator instructions directly.
117 unsigned getSuccessorIndex() const { return Idx; }
119 inline bool operator==(const _Self& x) const { return idx == x.idx; }
120 inline bool operator!=(const _Self& x) const { return !operator==(x); }
122 inline pointer operator*() const { return Term->getSuccessor(idx); }
123 inline pointer operator->() const { return operator*(); }
125 inline _Self& operator++() { ++idx; return *this; } // Preincrement
126 inline _Self operator++(int) { // Postincrement
127 _Self tmp = *this; ++*this; return tmp;
130 inline _Self& operator--() { --idx; return *this; } // Predecrement
131 inline _Self operator--(int) { // Postdecrement
132 _Self tmp = *this; --*this; return tmp;
136 typedef SuccIterator<TerminatorInst*, BasicBlock> succ_iterator;
137 typedef SuccIterator<const TerminatorInst*,
138 const BasicBlock> succ_const_iterator;
140 inline succ_iterator succ_begin(BasicBlock *BB) {
141 return succ_iterator(BB->getTerminator());
143 inline succ_const_iterator succ_begin(const BasicBlock *BB) {
144 return succ_const_iterator(BB->getTerminator());
146 inline succ_iterator succ_end(BasicBlock *BB) {
147 return succ_iterator(BB->getTerminator(), true);
149 inline succ_const_iterator succ_end(const BasicBlock *BB) {
150 return succ_const_iterator(BB->getTerminator(), true);
155 //===--------------------------------------------------------------------===//
156 // GraphTraits specializations for basic block graphs (CFGs)
157 //===--------------------------------------------------------------------===//
159 // Provide specializations of GraphTraits to be able to treat a function as a
160 // graph of basic blocks...
162 template <> struct GraphTraits<BasicBlock*> {
163 typedef BasicBlock NodeType;
164 typedef succ_iterator ChildIteratorType;
166 static NodeType *getEntryNode(BasicBlock *BB) { return BB; }
167 static inline ChildIteratorType child_begin(NodeType *N) {
168 return succ_begin(N);
170 static inline ChildIteratorType child_end(NodeType *N) {
175 template <> struct GraphTraits<const BasicBlock*> {
176 typedef const BasicBlock NodeType;
177 typedef succ_const_iterator ChildIteratorType;
179 static NodeType *getEntryNode(const BasicBlock *BB) { return BB; }
181 static inline ChildIteratorType child_begin(NodeType *N) {
182 return succ_begin(N);
184 static inline ChildIteratorType child_end(NodeType *N) {
189 // Provide specializations of GraphTraits to be able to treat a function as a
190 // graph of basic blocks... and to walk it in inverse order. Inverse order for
191 // a function is considered to be when traversing the predecessor edges of a BB
192 // instead of the successor edges.
194 template <> struct GraphTraits<Inverse<BasicBlock*> > {
195 typedef BasicBlock NodeType;
196 typedef pred_iterator ChildIteratorType;
197 static NodeType *getEntryNode(Inverse<BasicBlock *> G) { return G.Graph; }
198 static inline ChildIteratorType child_begin(NodeType *N) {
199 return pred_begin(N);
201 static inline ChildIteratorType child_end(NodeType *N) {
206 template <> struct GraphTraits<Inverse<const BasicBlock*> > {
207 typedef const BasicBlock NodeType;
208 typedef pred_const_iterator ChildIteratorType;
209 static NodeType *getEntryNode(Inverse<const BasicBlock*> G) {
212 static inline ChildIteratorType child_begin(NodeType *N) {
213 return pred_begin(N);
215 static inline ChildIteratorType child_end(NodeType *N) {
222 //===--------------------------------------------------------------------===//
223 // GraphTraits specializations for function basic block graphs (CFGs)
224 //===--------------------------------------------------------------------===//
226 // Provide specializations of GraphTraits to be able to treat a function as a
227 // graph of basic blocks... these are the same as the basic block iterators,
228 // except that the root node is implicitly the first node of the function.
230 template <> struct GraphTraits<Function*> : public GraphTraits<BasicBlock*> {
231 static NodeType *getEntryNode(Function *F) { return &F->getEntryBlock(); }
233 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
234 typedef Function::iterator nodes_iterator;
235 static nodes_iterator nodes_begin(Function *F) { return F->begin(); }
236 static nodes_iterator nodes_end (Function *F) { return F->end(); }
238 template <> struct GraphTraits<const Function*> :
239 public GraphTraits<const BasicBlock*> {
240 static NodeType *getEntryNode(const Function *F) {return &F->getEntryBlock();}
242 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
243 typedef Function::const_iterator nodes_iterator;
244 static nodes_iterator nodes_begin(const Function *F) { return F->begin(); }
245 static nodes_iterator nodes_end (const Function *F) { return F->end(); }
249 // Provide specializations of GraphTraits to be able to treat a function as a
250 // graph of basic blocks... and to walk it in inverse order. Inverse order for
251 // a function is considered to be when traversing the predecessor edges of a BB
252 // instead of the successor edges.
254 template <> struct GraphTraits<Inverse<Function*> > :
255 public GraphTraits<Inverse<BasicBlock*> > {
256 static NodeType *getEntryNode(Inverse<Function*> G) {
257 return &G.Graph->getEntryBlock();
260 template <> struct GraphTraits<Inverse<const Function*> > :
261 public GraphTraits<Inverse<const BasicBlock*> > {
262 static NodeType *getEntryNode(Inverse<const Function *> G) {
263 return &G.Graph->getEntryBlock();