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 helpers
111 //===----------------------------------------------------------------------===//
113 typedef TerminatorInst::SuccIterator<TerminatorInst *, BasicBlock>
115 typedef TerminatorInst::SuccIterator<const TerminatorInst *, const BasicBlock>
117 typedef llvm::iterator_range<succ_iterator> succ_range;
118 typedef llvm::iterator_range<succ_const_iterator> succ_const_range;
120 inline succ_iterator succ_begin(BasicBlock *BB) {
121 return succ_iterator(BB->getTerminator());
123 inline succ_const_iterator succ_begin(const BasicBlock *BB) {
124 return succ_const_iterator(BB->getTerminator());
126 inline succ_iterator succ_end(BasicBlock *BB) {
127 return succ_iterator(BB->getTerminator(), true);
129 inline succ_const_iterator succ_end(const BasicBlock *BB) {
130 return succ_const_iterator(BB->getTerminator(), true);
132 inline bool succ_empty(const BasicBlock *BB) {
133 return succ_begin(BB) == succ_end(BB);
135 inline succ_range successors(BasicBlock *BB) {
136 return succ_range(succ_begin(BB), succ_end(BB));
138 inline succ_const_range successors(const BasicBlock *BB) {
139 return succ_const_range(succ_begin(BB), succ_end(BB));
142 template <typename T, typename U>
143 struct isPodLike<TerminatorInst::SuccIterator<T, U>> {
144 static const bool value = isPodLike<T>::value;
149 //===--------------------------------------------------------------------===//
150 // GraphTraits specializations for basic block graphs (CFGs)
151 //===--------------------------------------------------------------------===//
153 // Provide specializations of GraphTraits to be able to treat a function as a
154 // graph of basic blocks...
156 template <> struct GraphTraits<BasicBlock*> {
157 typedef BasicBlock NodeType;
158 typedef BasicBlock *NodeRef;
159 typedef succ_iterator ChildIteratorType;
161 static NodeType *getEntryNode(BasicBlock *BB) { return BB; }
162 static inline ChildIteratorType child_begin(NodeType *N) {
163 return succ_begin(N);
165 static inline ChildIteratorType child_end(NodeType *N) {
170 template <> struct GraphTraits<const BasicBlock*> {
171 typedef const BasicBlock NodeType;
172 typedef const BasicBlock *NodeRef;
173 typedef succ_const_iterator ChildIteratorType;
175 static NodeType *getEntryNode(const BasicBlock *BB) { return BB; }
177 static inline ChildIteratorType child_begin(NodeType *N) {
178 return succ_begin(N);
180 static inline ChildIteratorType child_end(NodeType *N) {
185 // Provide specializations of GraphTraits to be able to treat a function as a
186 // graph of basic blocks... and to walk it in inverse order. Inverse order for
187 // a function is considered to be when traversing the predecessor edges of a BB
188 // instead of the successor edges.
190 template <> struct GraphTraits<Inverse<BasicBlock*> > {
191 typedef BasicBlock NodeType;
192 typedef BasicBlock *NodeRef;
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 const BasicBlock *NodeRef;
206 typedef const_pred_iterator ChildIteratorType;
207 static NodeType *getEntryNode(Inverse<const BasicBlock*> G) {
210 static inline ChildIteratorType child_begin(NodeType *N) {
211 return pred_begin(N);
213 static inline ChildIteratorType child_end(NodeType *N) {
220 //===--------------------------------------------------------------------===//
221 // GraphTraits specializations for function basic block graphs (CFGs)
222 //===--------------------------------------------------------------------===//
224 // Provide specializations of GraphTraits to be able to treat a function as a
225 // graph of basic blocks... these are the same as the basic block iterators,
226 // except that the root node is implicitly the first node of the function.
228 template <> struct GraphTraits<Function*> : public GraphTraits<BasicBlock*> {
229 static NodeType *getEntryNode(Function *F) { return &F->getEntryBlock(); }
231 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
232 typedef Function::iterator nodes_iterator;
233 static nodes_iterator nodes_begin(Function *F) { return F->begin(); }
234 static nodes_iterator nodes_end (Function *F) { return F->end(); }
235 static size_t size (Function *F) { return F->size(); }
237 template <> struct GraphTraits<const Function*> :
238 public GraphTraits<const BasicBlock*> {
239 static NodeType *getEntryNode(const Function *F) {return &F->getEntryBlock();}
241 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
242 typedef Function::const_iterator nodes_iterator;
243 static nodes_iterator nodes_begin(const Function *F) { return F->begin(); }
244 static nodes_iterator nodes_end (const Function *F) { return F->end(); }
245 static size_t size (const Function *F) { return F->size(); }
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();
267 } // End llvm namespace