summaryrefslogtreecommitdiff
path: root/include/llvm/Support/CFG.h
blob: f5dc8ea055a37e064f4f0776714a2fe887f4ea9e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
//===-- llvm/Support/CFG.h - Process LLVM structures as graphs --*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines specializations of GraphTraits that allow Function and
// BasicBlock graphs to be treated as proper graphs for generic algorithms.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_SUPPORT_CFG_H
#define LLVM_SUPPORT_CFG_H

#include "llvm/ADT/GraphTraits.h"
#include "llvm/Function.h"
#include "llvm/InstrTypes.h"

namespace llvm {

//===----------------------------------------------------------------------===//
// BasicBlock pred_iterator definition
//===----------------------------------------------------------------------===//

template <class Ptr, class USE_iterator> // Predecessor Iterator
class PredIterator : public std::iterator<std::forward_iterator_tag,
                                          Ptr, ptrdiff_t> {
  typedef std::iterator<std::forward_iterator_tag, Ptr, ptrdiff_t> super;
  typedef PredIterator<Ptr, USE_iterator> Self;
  USE_iterator It;

  inline void advancePastNonTerminators() {
    // Loop to ignore non terminator uses (for example BlockAddresses).
    while (!It.atEnd() && !isa<TerminatorInst>(*It))
      ++It;
  }

public:
  typedef typename super::pointer pointer;

  PredIterator() {}
  explicit inline PredIterator(Ptr *bb) : It(bb->use_begin()) {
    advancePastNonTerminators();
  }
  inline PredIterator(Ptr *bb, bool) : It(bb->use_end()) {}

  inline bool operator==(const Self& x) const { return It == x.It; }
  inline bool operator!=(const Self& x) const { return !operator==(x); }

  inline pointer operator*() const {
    assert(!It.atEnd() && "pred_iterator out of range!");
    return cast<TerminatorInst>(*It)->getParent();
  }
  inline pointer *operator->() const { return &operator*(); }

  inline Self& operator++() {   // Preincrement
    assert(!It.atEnd() && "pred_iterator out of range!");
    ++It; advancePastNonTerminators();
    return *this;
  }

  inline Self operator++(int) { // Postincrement
    Self tmp = *this; ++*this; return tmp;
  }

  /// getOperandNo - Return the operand number in the predecessor's
  /// terminator of the successor.
  unsigned getOperandNo() const {
    return It.getOperandNo();
  }

  /// getUse - Return the operand Use in the predecessor's terminator
  /// of the successor.
  Use &getUse() const {
    return It.getUse();
  }
};

typedef PredIterator<BasicBlock, Value::use_iterator> pred_iterator;
typedef PredIterator<const BasicBlock,
                     Value::const_use_iterator> const_pred_iterator;

inline pred_iterator pred_begin(BasicBlock *BB) { return pred_iterator(BB); }
inline const_pred_iterator pred_begin(const BasicBlock *BB) {
  return const_pred_iterator(BB);
}
inline pred_iterator pred_end(BasicBlock *BB) { return pred_iterator(BB, true);}
inline const_pred_iterator pred_end(const BasicBlock *BB) {
  return const_pred_iterator(BB, true);
}



//===----------------------------------------------------------------------===//
// BasicBlock succ_iterator definition
//===----------------------------------------------------------------------===//

template <class Term_, class BB_>           // Successor Iterator
class SuccIterator : public std::iterator<std::bidirectional_iterator_tag,
                                          BB_, ptrdiff_t> {
  const Term_ Term;
  unsigned idx;
  typedef std::iterator<std::bidirectional_iterator_tag, BB_, ptrdiff_t> super;
  typedef SuccIterator<Term_, BB_> Self;

  inline bool index_is_valid(int idx) {
    return idx >= 0 && (unsigned) idx < Term->getNumSuccessors();
  }

public:
  typedef typename super::pointer pointer;
  // TODO: This can be random access iterator, only operator[] missing.

  explicit inline SuccIterator(Term_ T) : Term(T), idx(0) {// begin iterator
  }
  inline SuccIterator(Term_ T, bool)                       // end iterator
    : Term(T) {
    if (Term)
      idx = Term->getNumSuccessors();
    else
      // Term == NULL happens, if a basic block is not fully constructed and
      // consequently getTerminator() returns NULL. In this case we construct a
      // SuccIterator which describes a basic block that has zero successors.
      // Defining SuccIterator for incomplete and malformed CFGs is especially
      // useful for debugging.
      idx = 0;
  }

  inline const Self &operator=(const Self &I) {
    assert(Term == I.Term &&"Cannot assign iterators to two different blocks!");
    idx = I.idx;
    return *this;
  }

  /// getSuccessorIndex - This is used to interface between code that wants to
  /// operate on terminator instructions directly.
  unsigned getSuccessorIndex() const { return idx; }

  inline bool operator==(const Self& x) const { return idx == x.idx; }
  inline bool operator!=(const Self& x) const { return !operator==(x); }

  inline pointer operator*() const { return Term->getSuccessor(idx); }
  inline pointer operator->() const { return operator*(); }

  inline Self& operator++() { ++idx; return *this; } // Preincrement

  inline Self operator++(int) { // Postincrement
    Self tmp = *this; ++*this; return tmp;
  }

  inline Self& operator--() { --idx; return *this; }  // Predecrement
  inline Self operator--(int) { // Postdecrement
    Self tmp = *this; --*this; return tmp;
  }

  inline bool operator<(const Self& x) const {
    assert(Term == x.Term && "Cannot compare iterators of different blocks!");
    return idx < x.idx;
  }

  inline bool operator<=(const Self& x) const {
    assert(Term == x.Term && "Cannot compare iterators of different blocks!");
    return idx <= x.idx;
  }
  inline bool operator>=(const Self& x) const {
    assert(Term == x.Term && "Cannot compare iterators of different blocks!");
    return idx >= x.idx;
  }

  inline bool operator>(const Self& x) const {
    assert(Term == x.Term && "Cannot compare iterators of different blocks!");
    return idx > x.idx;
  }

  inline Self& operator+=(int Right) {
    unsigned new_idx = idx + Right;
    assert(index_is_valid(new_idx) && "Iterator index out of bound");
    idx = new_idx;
    return *this;
  }

  inline Self operator+(int Right) {
    Self tmp = *this;
    tmp += Right;
    return tmp;
  }

  inline Self& operator-=(int Right) {
    return operator+=(-Right);
  }

  inline Self operator-(int Right) {
    return operator+(-Right);
  }

  inline int operator-(const Self& x) {
    assert(Term == x.Term && "Cannot work on iterators of different blocks!");
    int distance = idx - x.idx;
    return distance;
  }

  // This works for read access, however write access is difficult as changes
  // to Term are only possible with Term->setSuccessor(idx). Pointers that can
  // be modified are not available.
  //
  // inline pointer operator[](int offset) {
  //  Self tmp = *this;
  //  tmp += offset;
  //  return tmp.operator*();
  // }

  /// Get the source BB of this iterator.
  inline BB_ *getSource() {
    assert(Term && "Source not available, if basic block was malformed");
    return Term->getParent();
  }
};

typedef SuccIterator<TerminatorInst*, BasicBlock> succ_iterator;
typedef SuccIterator<const TerminatorInst*,
                     const BasicBlock> succ_const_iterator;

inline succ_iterator succ_begin(BasicBlock *BB) {
  return succ_iterator(BB->getTerminator());
}
inline succ_const_iterator succ_begin(const BasicBlock *BB) {
  return succ_const_iterator(BB->getTerminator());
}
inline succ_iterator succ_end(BasicBlock *BB) {
  return succ_iterator(BB->getTerminator(), true);
}
inline succ_const_iterator succ_end(const BasicBlock *BB) {
  return succ_const_iterator(BB->getTerminator(), true);
}



//===--------------------------------------------------------------------===//
// GraphTraits specializations for basic block graphs (CFGs)
//===--------------------------------------------------------------------===//

// Provide specializations of GraphTraits to be able to treat a function as a
// graph of basic blocks...

template <> struct GraphTraits<BasicBlock*> {
  typedef BasicBlock NodeType;
  typedef succ_iterator ChildIteratorType;

  static NodeType *getEntryNode(BasicBlock *BB) { return BB; }
  static inline ChildIteratorType child_begin(NodeType *N) {
    return succ_begin(N);
  }
  static inline ChildIteratorType child_end(NodeType *N) {
    return succ_end(N);
  }
};

template <> struct GraphTraits<const BasicBlock*> {
  typedef const BasicBlock NodeType;
  typedef succ_const_iterator ChildIteratorType;

  static NodeType *getEntryNode(const BasicBlock *BB) { return BB; }

  static inline ChildIteratorType child_begin(NodeType *N) {
    return succ_begin(N);
  }
  static inline ChildIteratorType child_end(NodeType *N) {
    return succ_end(N);
  }
};

// Provide specializations of GraphTraits to be able to treat a function as a
// graph of basic blocks... and to walk it in inverse order.  Inverse order for
// a function is considered to be when traversing the predecessor edges of a BB
// instead of the successor edges.
//
template <> struct GraphTraits<Inverse<BasicBlock*> > {
  typedef BasicBlock NodeType;
  typedef pred_iterator ChildIteratorType;
  static NodeType *getEntryNode(Inverse<BasicBlock *> G) { return G.Graph; }
  static inline ChildIteratorType child_begin(NodeType *N) {
    return pred_begin(N);
  }
  static inline ChildIteratorType child_end(NodeType *N) {
    return pred_end(N);
  }
};

template <> struct GraphTraits<Inverse<const BasicBlock*> > {
  typedef const BasicBlock NodeType;
  typedef const_pred_iterator ChildIteratorType;
  static NodeType *getEntryNode(Inverse<const BasicBlock*> G) {
    return G.Graph;
  }
  static inline ChildIteratorType child_begin(NodeType *N) {
    return pred_begin(N);
  }
  static inline ChildIteratorType child_end(NodeType *N) {
    return pred_end(N);
  }
};



//===--------------------------------------------------------------------===//
// GraphTraits specializations for function basic block graphs (CFGs)
//===--------------------------------------------------------------------===//

// Provide specializations of GraphTraits to be able to treat a function as a
// graph of basic blocks... these are the same as the basic block iterators,
// except that the root node is implicitly the first node of the function.
//
template <> struct GraphTraits<Function*> : public GraphTraits<BasicBlock*> {
  static NodeType *getEntryNode(Function *F) { return &F->getEntryBlock(); }

  // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
  typedef Function::iterator nodes_iterator;
  static nodes_iterator nodes_begin(Function *F) { return F->begin(); }
  static nodes_iterator nodes_end  (Function *F) { return F->end(); }
  static unsigned       size       (Function *F) { return F->size(); }
};
template <> struct GraphTraits<const Function*> :
  public GraphTraits<const BasicBlock*> {
  static NodeType *getEntryNode(const Function *F) {return &F->getEntryBlock();}

  // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
  typedef Function::const_iterator nodes_iterator;
  static nodes_iterator nodes_begin(const Function *F) { return F->begin(); }
  static nodes_iterator nodes_end  (const Function *F) { return F->end(); }
  static unsigned       size       (const Function *F) { return F->size(); }
};


// Provide specializations of GraphTraits to be able to treat a function as a
// graph of basic blocks... and to walk it in inverse order.  Inverse order for
// a function is considered to be when traversing the predecessor edges of a BB
// instead of the successor edges.
//
template <> struct GraphTraits<Inverse<Function*> > :
  public GraphTraits<Inverse<BasicBlock*> > {
  static NodeType *getEntryNode(Inverse<Function*> G) {
    return &G.Graph->getEntryBlock();
  }
};
template <> struct GraphTraits<Inverse<const Function*> > :
  public GraphTraits<Inverse<const BasicBlock*> > {
  static NodeType *getEntryNode(Inverse<const Function *> G) {
    return &G.Graph->getEntryBlock();
  }
};

} // End llvm namespace

#endif