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.h"
20 #include "llvm/ADT/iterator_range.h"
21 #include "llvm/IR/BasicBlock.h"
22 #include "llvm/IR/Function.h"
23 #include "llvm/IR/InstrTypes.h"
24 #include "llvm/IR/Value.h"
25 #include "llvm/Support/Casting.h"
26 #include "llvm/Support/type_traits.h"
33 //===----------------------------------------------------------------------===//
34 // BasicBlock pred_iterator definition
35 //===----------------------------------------------------------------------===//
37 template <class Ptr, class USE_iterator> // Predecessor Iterator
38 class PredIterator : public std::iterator<std::forward_iterator_tag,
39 Ptr, ptrdiff_t, Ptr*, Ptr*> {
40 typedef std::iterator<std::forward_iterator_tag, Ptr, ptrdiff_t, Ptr*,
42 typedef PredIterator<Ptr, USE_iterator> Self;
45 inline void advancePastNonTerminators() {
46 // Loop to ignore non-terminator uses (for example BlockAddresses).
47 while (!It.atEnd() && !isa<TerminatorInst>(*It))
52 typedef typename super::pointer pointer;
53 typedef typename super::reference reference;
55 PredIterator() = default;
56 explicit inline PredIterator(Ptr *bb) : It(bb->user_begin()) {
57 advancePastNonTerminators();
59 inline PredIterator(Ptr *bb, bool) : It(bb->user_end()) {}
61 inline bool operator==(const Self& x) const { return It == x.It; }
62 inline bool operator!=(const Self& x) const { return !operator==(x); }
64 inline reference operator*() const {
65 assert(!It.atEnd() && "pred_iterator out of range!");
66 return cast<TerminatorInst>(*It)->getParent();
68 inline pointer *operator->() const { return &operator*(); }
70 inline Self& operator++() { // Preincrement
71 assert(!It.atEnd() && "pred_iterator out of range!");
72 ++It; advancePastNonTerminators();
76 inline Self operator++(int) { // Postincrement
77 Self tmp = *this; ++*this; return tmp;
80 /// getOperandNo - Return the operand number in the predecessor's
81 /// terminator of the successor.
82 unsigned getOperandNo() const {
83 return It.getOperandNo();
86 /// getUse - Return the operand Use in the predecessor's terminator
93 typedef PredIterator<BasicBlock, Value::user_iterator> pred_iterator;
94 typedef PredIterator<const BasicBlock,
95 Value::const_user_iterator> const_pred_iterator;
96 typedef iterator_range<pred_iterator> pred_range;
97 typedef iterator_range<const_pred_iterator> pred_const_range;
99 inline pred_iterator pred_begin(BasicBlock *BB) { return pred_iterator(BB); }
100 inline const_pred_iterator pred_begin(const BasicBlock *BB) {
101 return const_pred_iterator(BB);
103 inline pred_iterator pred_end(BasicBlock *BB) { return pred_iterator(BB, true);}
104 inline const_pred_iterator pred_end(const BasicBlock *BB) {
105 return const_pred_iterator(BB, true);
107 inline bool pred_empty(const BasicBlock *BB) {
108 return pred_begin(BB) == pred_end(BB);
110 inline pred_range predecessors(BasicBlock *BB) {
111 return pred_range(pred_begin(BB), pred_end(BB));
113 inline pred_const_range predecessors(const BasicBlock *BB) {
114 return pred_const_range(pred_begin(BB), pred_end(BB));
117 //===----------------------------------------------------------------------===//
118 // BasicBlock succ_iterator helpers
119 //===----------------------------------------------------------------------===//
121 typedef TerminatorInst::SuccIterator<TerminatorInst *, BasicBlock>
123 typedef TerminatorInst::SuccIterator<const TerminatorInst *, const BasicBlock>
125 typedef iterator_range<succ_iterator> succ_range;
126 typedef iterator_range<succ_const_iterator> succ_const_range;
128 inline succ_iterator succ_begin(BasicBlock *BB) {
129 return succ_iterator(BB->getTerminator());
131 inline succ_const_iterator succ_begin(const BasicBlock *BB) {
132 return succ_const_iterator(BB->getTerminator());
134 inline succ_iterator succ_end(BasicBlock *BB) {
135 return succ_iterator(BB->getTerminator(), true);
137 inline succ_const_iterator succ_end(const BasicBlock *BB) {
138 return succ_const_iterator(BB->getTerminator(), true);
140 inline bool succ_empty(const BasicBlock *BB) {
141 return succ_begin(BB) == succ_end(BB);
143 inline succ_range successors(BasicBlock *BB) {
144 return succ_range(succ_begin(BB), succ_end(BB));
146 inline succ_const_range successors(const BasicBlock *BB) {
147 return succ_const_range(succ_begin(BB), succ_end(BB));
150 template <typename T, typename U>
151 struct isPodLike<TerminatorInst::SuccIterator<T, U>> {
152 static const bool value = isPodLike<T>::value;
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 *NodeRef;
164 typedef succ_iterator ChildIteratorType;
166 static NodeRef getEntryNode(BasicBlock *BB) { return BB; }
167 static ChildIteratorType child_begin(NodeRef N) { return succ_begin(N); }
168 static ChildIteratorType child_end(NodeRef N) { return succ_end(N); }
171 template <> struct GraphTraits<const BasicBlock*> {
172 typedef const BasicBlock *NodeRef;
173 typedef succ_const_iterator ChildIteratorType;
175 static NodeRef getEntryNode(const BasicBlock *BB) { return BB; }
177 static ChildIteratorType child_begin(NodeRef N) { return succ_begin(N); }
178 static ChildIteratorType child_end(NodeRef N) { return succ_end(N); }
181 // Provide specializations of GraphTraits to be able to treat a function as a
182 // graph of basic blocks... and to walk it in inverse order. Inverse order for
183 // a function is considered to be when traversing the predecessor edges of a BB
184 // instead of the successor edges.
186 template <> struct GraphTraits<Inverse<BasicBlock*>> {
187 typedef BasicBlock *NodeRef;
188 typedef pred_iterator ChildIteratorType;
189 static NodeRef getEntryNode(Inverse<BasicBlock *> G) { return G.Graph; }
190 static ChildIteratorType child_begin(NodeRef N) { return pred_begin(N); }
191 static ChildIteratorType child_end(NodeRef N) { return pred_end(N); }
194 template <> struct GraphTraits<Inverse<const BasicBlock*>> {
195 typedef const BasicBlock *NodeRef;
196 typedef const_pred_iterator ChildIteratorType;
197 static NodeRef getEntryNode(Inverse<const BasicBlock *> G) { return G.Graph; }
198 static ChildIteratorType child_begin(NodeRef N) { return pred_begin(N); }
199 static ChildIteratorType child_end(NodeRef N) { return pred_end(N); }
202 //===--------------------------------------------------------------------===//
203 // GraphTraits specializations for function basic block graphs (CFGs)
204 //===--------------------------------------------------------------------===//
206 // Provide specializations of GraphTraits to be able to treat a function as a
207 // graph of basic blocks... these are the same as the basic block iterators,
208 // except that the root node is implicitly the first node of the function.
210 template <> struct GraphTraits<Function*> : public GraphTraits<BasicBlock*> {
211 static NodeRef getEntryNode(Function *F) { return &F->getEntryBlock(); }
213 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
214 typedef pointer_iterator<Function::iterator> nodes_iterator;
216 static nodes_iterator nodes_begin(Function *F) {
217 return nodes_iterator(F->begin());
220 static nodes_iterator nodes_end(Function *F) {
221 return nodes_iterator(F->end());
224 static size_t size(Function *F) { return F->size(); }
226 template <> struct GraphTraits<const Function*> :
227 public GraphTraits<const BasicBlock*> {
228 static NodeRef getEntryNode(const Function *F) { return &F->getEntryBlock(); }
230 // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
231 typedef pointer_iterator<Function::const_iterator> nodes_iterator;
233 static nodes_iterator nodes_begin(const Function *F) {
234 return nodes_iterator(F->begin());
237 static nodes_iterator nodes_end(const Function *F) {
238 return nodes_iterator(F->end());
241 static size_t size(const Function *F) { return F->size(); }
244 // Provide specializations of GraphTraits to be able to treat a function as a
245 // graph of basic blocks... and to walk it in inverse order. Inverse order for
246 // a function is considered to be when traversing the predecessor edges of a BB
247 // instead of the successor edges.
249 template <> struct GraphTraits<Inverse<Function*>> :
250 public GraphTraits<Inverse<BasicBlock*>> {
251 static NodeRef getEntryNode(Inverse<Function *> G) {
252 return &G.Graph->getEntryBlock();
255 template <> struct GraphTraits<Inverse<const Function*>> :
256 public GraphTraits<Inverse<const BasicBlock*>> {
257 static NodeRef getEntryNode(Inverse<const Function *> G) {
258 return &G.Graph->getEntryBlock();
262 } // end namespace llvm
264 #endif // LLVM_IR_CFG_H