LLVM  6.0.0svn
MapVector.h
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1 //===- llvm/ADT/MapVector.h - Map w/ deterministic value order --*- 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 implements a map that provides insertion order iteration. The
11 // interface is purposefully minimal. The key is assumed to be cheap to copy
12 // and 2 copies are kept, one for indexing in a DenseMap, one for iteration in
13 // a std::vector.
14 //
15 //===----------------------------------------------------------------------===//
16 
17 #ifndef LLVM_ADT_MAPVECTOR_H
18 #define LLVM_ADT_MAPVECTOR_H
19 
20 #include "llvm/ADT/DenseMap.h"
21 #include "llvm/ADT/SmallVector.h"
22 #include <algorithm>
23 #include <cassert>
24 #include <cstddef>
25 #include <iterator>
26 #include <type_traits>
27 #include <utility>
28 #include <vector>
29 
30 namespace llvm {
31 
32 /// This class implements a map that also provides access to all stored values
33 /// in a deterministic order. The values are kept in a std::vector and the
34 /// mapping is done with DenseMap from Keys to indexes in that vector.
35 template<typename KeyT, typename ValueT,
36  typename MapType = DenseMap<KeyT, unsigned>,
37  typename VectorType = std::vector<std::pair<KeyT, ValueT>>>
38 class MapVector {
39  using value_type = typename VectorType::value_type;
40  using size_type = typename VectorType::size_type;
41 
42  MapType Map;
43  VectorType Vector;
44 
45 public:
46  using iterator = typename VectorType::iterator;
47  using const_iterator = typename VectorType::const_iterator;
48  using reverse_iterator = typename VectorType::reverse_iterator;
49  using const_reverse_iterator = typename VectorType::const_reverse_iterator;
50 
51  /// Clear the MapVector and return the underlying vector.
52  VectorType takeVector() {
53  Map.clear();
54  return std::move(Vector);
55  }
56 
57  size_type size() const { return Vector.size(); }
58 
59  /// Grow the MapVector so that it can contain at least \p NumEntries items
60  /// before resizing again.
61  void reserve(size_type NumEntries) {
62  Map.reserve(NumEntries);
63  Vector.reserve(NumEntries);
64  }
65 
66  iterator begin() { return Vector.begin(); }
67  const_iterator begin() const { return Vector.begin(); }
68  iterator end() { return Vector.end(); }
69  const_iterator end() const { return Vector.end(); }
70 
71  reverse_iterator rbegin() { return Vector.rbegin(); }
72  const_reverse_iterator rbegin() const { return Vector.rbegin(); }
73  reverse_iterator rend() { return Vector.rend(); }
74  const_reverse_iterator rend() const { return Vector.rend(); }
75 
76  bool empty() const {
77  return Vector.empty();
78  }
79 
80  std::pair<KeyT, ValueT> &front() { return Vector.front(); }
81  const std::pair<KeyT, ValueT> &front() const { return Vector.front(); }
82  std::pair<KeyT, ValueT> &back() { return Vector.back(); }
83  const std::pair<KeyT, ValueT> &back() const { return Vector.back(); }
84 
85  void clear() {
86  Map.clear();
87  Vector.clear();
88  }
89 
90  void swap(MapVector &RHS) {
91  std::swap(Map, RHS.Map);
92  std::swap(Vector, RHS.Vector);
93  }
94 
95  ValueT &operator[](const KeyT &Key) {
96  std::pair<KeyT, unsigned> Pair = std::make_pair(Key, 0);
97  std::pair<typename MapType::iterator, bool> Result = Map.insert(Pair);
98  unsigned &I = Result.first->second;
99  if (Result.second) {
100  Vector.push_back(std::make_pair(Key, ValueT()));
101  I = Vector.size() - 1;
102  }
103  return Vector[I].second;
104  }
105 
106  // Returns a copy of the value. Only allowed if ValueT is copyable.
107  ValueT lookup(const KeyT &Key) const {
108  static_assert(std::is_copy_constructible<ValueT>::value,
109  "Cannot call lookup() if ValueT is not copyable.");
110  typename MapType::const_iterator Pos = Map.find(Key);
111  return Pos == Map.end()? ValueT() : Vector[Pos->second].second;
112  }
113 
114  std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &KV) {
115  std::pair<KeyT, unsigned> Pair = std::make_pair(KV.first, 0);
116  std::pair<typename MapType::iterator, bool> Result = Map.insert(Pair);
117  unsigned &I = Result.first->second;
118  if (Result.second) {
119  Vector.push_back(std::make_pair(KV.first, KV.second));
120  I = Vector.size() - 1;
121  return std::make_pair(std::prev(end()), true);
122  }
123  return std::make_pair(begin() + I, false);
124  }
125 
126  std::pair<iterator, bool> insert(std::pair<KeyT, ValueT> &&KV) {
127  // Copy KV.first into the map, then move it into the vector.
128  std::pair<KeyT, unsigned> Pair = std::make_pair(KV.first, 0);
129  std::pair<typename MapType::iterator, bool> Result = Map.insert(Pair);
130  unsigned &I = Result.first->second;
131  if (Result.second) {
132  Vector.push_back(std::move(KV));
133  I = Vector.size() - 1;
134  return std::make_pair(std::prev(end()), true);
135  }
136  return std::make_pair(begin() + I, false);
137  }
138 
139  size_type count(const KeyT &Key) const {
140  typename MapType::const_iterator Pos = Map.find(Key);
141  return Pos == Map.end()? 0 : 1;
142  }
143 
144  iterator find(const KeyT &Key) {
145  typename MapType::const_iterator Pos = Map.find(Key);
146  return Pos == Map.end()? Vector.end() :
147  (Vector.begin() + Pos->second);
148  }
149 
150  const_iterator find(const KeyT &Key) const {
151  typename MapType::const_iterator Pos = Map.find(Key);
152  return Pos == Map.end()? Vector.end() :
153  (Vector.begin() + Pos->second);
154  }
155 
156  /// \brief Remove the last element from the vector.
157  void pop_back() {
158  typename MapType::iterator Pos = Map.find(Vector.back().first);
159  Map.erase(Pos);
160  Vector.pop_back();
161  }
162 
163  /// \brief Remove the element given by Iterator.
164  ///
165  /// Returns an iterator to the element following the one which was removed,
166  /// which may be end().
167  ///
168  /// \note This is a deceivingly expensive operation (linear time). It's
169  /// usually better to use \a remove_if() if possible.
170  typename VectorType::iterator erase(typename VectorType::iterator Iterator) {
171  Map.erase(Iterator->first);
172  auto Next = Vector.erase(Iterator);
173  if (Next == Vector.end())
174  return Next;
175 
176  // Update indices in the map.
177  size_t Index = Next - Vector.begin();
178  for (auto &I : Map) {
179  assert(I.second != Index && "Index was already erased!");
180  if (I.second > Index)
181  --I.second;
182  }
183  return Next;
184  }
185 
186  /// \brief Remove all elements with the key value Key.
187  ///
188  /// Returns the number of elements removed.
189  size_type erase(const KeyT &Key) {
190  auto Iterator = find(Key);
191  if (Iterator == end())
192  return 0;
193  erase(Iterator);
194  return 1;
195  }
196 
197  /// \brief Remove the elements that match the predicate.
198  ///
199  /// Erase all elements that match \c Pred in a single pass. Takes linear
200  /// time.
201  template <class Predicate> void remove_if(Predicate Pred);
202 };
203 
204 template <typename KeyT, typename ValueT, typename MapType, typename VectorType>
205 template <class Function>
207  auto O = Vector.begin();
208  for (auto I = O, E = Vector.end(); I != E; ++I) {
209  if (Pred(*I)) {
210  // Erase from the map.
211  Map.erase(I->first);
212  continue;
213  }
214 
215  if (I != O) {
216  // Move the value and update the index in the map.
217  *O = std::move(*I);
218  Map[O->first] = O - Vector.begin();
219  }
220  ++O;
221  }
222  // Erase trailing entries in the vector.
223  Vector.erase(O, Vector.end());
224 }
225 
226 /// \brief A MapVector that performs no allocations if smaller than a certain
227 /// size.
228 template <typename KeyT, typename ValueT, unsigned N>
230  : MapVector<KeyT, ValueT, SmallDenseMap<KeyT, unsigned, N>,
231  SmallVector<std::pair<KeyT, ValueT>, N>> {
232 };
233 
234 } // end namespace llvm
235 
236 #endif // LLVM_ADT_MAPVECTOR_H
const_iterator begin() const
Definition: MapVector.h:67
void clear()
Definition: MapVector.h:85
const_reverse_iterator rend() const
Definition: MapVector.h:74
size_type size() const
Definition: MapVector.h:57
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
reverse_iterator rend()
Definition: MapVector.h:73
void pop_back()
Remove the last element from the vector.
Definition: MapVector.h:157
This class implements a map that also provides access to all stored values in a deterministic order...
Definition: MapVector.h:38
VectorType::iterator erase(typename VectorType::iterator Iterator)
Remove the element given by Iterator.
Definition: MapVector.h:170
std::pair< KeyT, ValueT > & back()
Definition: MapVector.h:82
A MapVector that performs no allocations if smaller than a certain size.
Definition: MapVector.h:229
ValueT & operator[](const KeyT &Key)
Definition: MapVector.h:95
bool empty() const
Definition: MapVector.h:76
Key
PAL metadata keys.
typename std::vector< std::pair< AssertingVH< Instruction >, AssertingVH< Value > >> ::const_reverse_iterator const_reverse_iterator
Definition: MapVector.h:49
iterator find(const KeyT &Key)
Definition: MapVector.h:144
typename std::vector< std::pair< AssertingVH< Instruction >, AssertingVH< Value > >> ::reverse_iterator reverse_iterator
Definition: MapVector.h:48
void remove_if(Predicate Pred)
Remove the elements that match the predicate.
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
const_iterator find(const KeyT &Key) const
Definition: MapVector.h:150
const std::pair< KeyT, ValueT > & back() const
Definition: MapVector.h:83
VectorType takeVector()
Clear the MapVector and return the underlying vector.
Definition: MapVector.h:52
std::pair< iterator, bool > insert(std::pair< KeyT, ValueT > &&KV)
Definition: MapVector.h:126
std::pair< iterator, bool > insert(const std::pair< KeyT, ValueT > &KV)
Definition: MapVector.h:114
Predicate
Predicate - These are "(BI << 5) | BO" for various predicates.
Definition: PPCPredicates.h:27
typename std::vector< std::pair< AssertingVH< Instruction >, AssertingVH< Value > >> ::const_iterator const_iterator
Definition: MapVector.h:47
size_type count(const KeyT &Key) const
Definition: MapVector.h:139
const std::pair< KeyT, ValueT > & front() const
Definition: MapVector.h:81
reverse_iterator rbegin()
Definition: MapVector.h:71
typename std::vector< std::pair< AssertingVH< Instruction >, AssertingVH< Value > >> ::iterator iterator
Definition: MapVector.h:46
void swap(llvm::BitVector &LHS, llvm::BitVector &RHS)
Implement std::swap in terms of BitVector swap.
Definition: BitVector.h:923
ValueT lookup(const KeyT &Key) const
Definition: MapVector.h:107
std::pair< KeyT, ValueT > & front()
Definition: MapVector.h:80
void reserve(size_type NumEntries)
Grow the MapVector so that it can contain at least NumEntries items before resizing again...
Definition: MapVector.h:61
const_reverse_iterator rbegin() const
Definition: MapVector.h:72
#define I(x, y, z)
Definition: MD5.cpp:58
size_type erase(const KeyT &Key)
Remove all elements with the key value Key.
Definition: MapVector.h:189
iterator begin()
Definition: MapVector.h:66
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
iterator end()
Definition: MapVector.h:68
const_iterator end() const
Definition: MapVector.h:69
void swap(MapVector &RHS)
Definition: MapVector.h:90