1//===- llvm/Support/InstIterator.h - Classes for inst iteration -*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file contains definitions of two iterators for iterating over the
11// instructions in a function.  This is effectively a wrapper around a two level
12// iterator that can probably be genericized later.
13//
14// Note that this iterator gets invalidated any time that basic blocks or
15// instructions are moved around.
16//
17//===----------------------------------------------------------------------===//
18
19#ifndef LLVM_SUPPORT_INSTITERATOR_H
20#define LLVM_SUPPORT_INSTITERATOR_H
21
22#include "llvm/IR/BasicBlock.h"
23#include "llvm/IR/Function.h"
24
25namespace llvm {
26
27// This class implements inst_begin() & inst_end() for
28// inst_iterator and const_inst_iterator's.
29//
30template <class _BB_t, class _BB_i_t, class _BI_t, class _II_t>
31class InstIterator {
32  typedef _BB_t   BBty;
33  typedef _BB_i_t BBIty;
34  typedef _BI_t   BIty;
35  typedef _II_t   IIty;
36  _BB_t  *BBs;      // BasicBlocksType
37  _BB_i_t BB;       // BasicBlocksType::iterator
38  _BI_t   BI;       // BasicBlock::iterator
39public:
40  typedef std::bidirectional_iterator_tag iterator_category;
41  typedef IIty                            value_type;
42  typedef signed                        difference_type;
43  typedef IIty*                           pointer;
44  typedef IIty&                           reference;
45
46  // Default constructor
47  InstIterator() {}
48
49  // Copy constructor...
50  template<typename A, typename B, typename C, typename D>
51  InstIterator(const InstIterator<A,B,C,D> &II)
52    : BBs(II.BBs), BB(II.BB), BI(II.BI) {}
53
54  template<typename A, typename B, typename C, typename D>
55  InstIterator(InstIterator<A,B,C,D> &II)
56    : BBs(II.BBs), BB(II.BB), BI(II.BI) {}
57
58  template<class M> InstIterator(M &m)
59    : BBs(&m.getBasicBlockList()), BB(BBs->begin()) {    // begin ctor
60    if (BB != BBs->end()) {
61      BI = BB->begin();
62      advanceToNextBB();
63    }
64  }
65
66  template<class M> InstIterator(M &m, bool)
67    : BBs(&m.getBasicBlockList()), BB(BBs->end()) {    // end ctor
68  }
69
70  // Accessors to get at the underlying iterators...
71  inline BBIty &getBasicBlockIterator()  { return BB; }
72  inline BIty  &getInstructionIterator() { return BI; }
73
74  inline reference operator*()  const { return *BI; }
75  inline pointer operator->() const { return &operator*(); }
76
77  inline bool operator==(const InstIterator &y) const {
78    return BB == y.BB && (BB == BBs->end() || BI == y.BI);
79  }
80  inline bool operator!=(const InstIterator& y) const {
81    return !operator==(y);
82  }
83
84  InstIterator& operator++() {
85    ++BI;
86    advanceToNextBB();
87    return *this;
88  }
89  inline InstIterator operator++(int) {
90    InstIterator tmp = *this; ++*this; return tmp;
91  }
92
93  InstIterator& operator--() {
94    while (BB == BBs->end() || BI == BB->begin()) {
95      --BB;
96      BI = BB->end();
97    }
98    --BI;
99    return *this;
100  }
101  inline InstIterator  operator--(int) {
102    InstIterator tmp = *this; --*this; return tmp;
103  }
104
105  inline bool atEnd() const { return BB == BBs->end(); }
106
107private:
108  inline void advanceToNextBB() {
109    // The only way that the II could be broken is if it is now pointing to
110    // the end() of the current BasicBlock and there are successor BBs.
111    while (BI == BB->end()) {
112      ++BB;
113      if (BB == BBs->end()) break;
114      BI = BB->begin();
115    }
116  }
117};
118
119
120typedef InstIterator<iplist<BasicBlock>,
121                     Function::iterator, BasicBlock::iterator,
122                     Instruction> inst_iterator;
123typedef InstIterator<const iplist<BasicBlock>,
124                     Function::const_iterator,
125                     BasicBlock::const_iterator,
126                     const Instruction> const_inst_iterator;
127
128inline inst_iterator inst_begin(Function *F) { return inst_iterator(*F); }
129inline inst_iterator inst_end(Function *F)   { return inst_iterator(*F, true); }
130inline const_inst_iterator inst_begin(const Function *F) {
131  return const_inst_iterator(*F);
132}
133inline const_inst_iterator inst_end(const Function *F) {
134  return const_inst_iterator(*F, true);
135}
136inline inst_iterator inst_begin(Function &F) { return inst_iterator(F); }
137inline inst_iterator inst_end(Function &F)   { return inst_iterator(F, true); }
138inline const_inst_iterator inst_begin(const Function &F) {
139  return const_inst_iterator(F);
140}
141inline const_inst_iterator inst_end(const Function &F) {
142  return const_inst_iterator(F, true);
143}
144
145} // End llvm namespace
146
147#endif
148