LLVM  8.0.0svn
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  MapType Map;
40  VectorType Vector;
41 
42  static_assert(
43  std::is_integral<typename MapType::mapped_type>::value,
44  "The mapped_type of the specified Map must be an integral type");
45 
46 public:
47  using value_type = typename VectorType::value_type;
48  using size_type = typename VectorType::size_type;
49 
50  using iterator = typename VectorType::iterator;
51  using const_iterator = typename VectorType::const_iterator;
52  using reverse_iterator = typename VectorType::reverse_iterator;
53  using const_reverse_iterator = typename VectorType::const_reverse_iterator;
54 
55  /// Clear the MapVector and return the underlying vector.
56  VectorType takeVector() {
57  Map.clear();
58  return std::move(Vector);
59  }
60 
61  size_type size() const { return Vector.size(); }
62 
63  /// Grow the MapVector so that it can contain at least \p NumEntries items
64  /// before resizing again.
65  void reserve(size_type NumEntries) {
66  Map.reserve(NumEntries);
67  Vector.reserve(NumEntries);
68  }
69 
70  iterator begin() { return Vector.begin(); }
71  const_iterator begin() const { return Vector.begin(); }
72  iterator end() { return Vector.end(); }
73  const_iterator end() const { return Vector.end(); }
74 
75  reverse_iterator rbegin() { return Vector.rbegin(); }
76  const_reverse_iterator rbegin() const { return Vector.rbegin(); }
77  reverse_iterator rend() { return Vector.rend(); }
78  const_reverse_iterator rend() const { return Vector.rend(); }
79 
80  bool empty() const {
81  return Vector.empty();
82  }
83 
84  std::pair<KeyT, ValueT> &front() { return Vector.front(); }
85  const std::pair<KeyT, ValueT> &front() const { return Vector.front(); }
86  std::pair<KeyT, ValueT> &back() { return Vector.back(); }
87  const std::pair<KeyT, ValueT> &back() const { return Vector.back(); }
88 
89  void clear() {
90  Map.clear();
91  Vector.clear();
92  }
93 
94  void swap(MapVector &RHS) {
95  std::swap(Map, RHS.Map);
96  std::swap(Vector, RHS.Vector);
97  }
98 
99  ValueT &operator[](const KeyT &Key) {
100  std::pair<KeyT, typename MapType::mapped_type> Pair = std::make_pair(Key, 0);
101  std::pair<typename MapType::iterator, bool> Result = Map.insert(Pair);
102  auto &I = Result.first->second;
103  if (Result.second) {
104  Vector.push_back(std::make_pair(Key, ValueT()));
105  I = Vector.size() - 1;
106  }
107  return Vector[I].second;
108  }
109 
110  // Returns a copy of the value. Only allowed if ValueT is copyable.
111  ValueT lookup(const KeyT &Key) const {
112  static_assert(std::is_copy_constructible<ValueT>::value,
113  "Cannot call lookup() if ValueT is not copyable.");
114  typename MapType::const_iterator Pos = Map.find(Key);
115  return Pos == Map.end()? ValueT() : Vector[Pos->second].second;
116  }
117 
118  std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &KV) {
119  std::pair<KeyT, typename MapType::mapped_type> Pair = std::make_pair(KV.first, 0);
120  std::pair<typename MapType::iterator, bool> Result = Map.insert(Pair);
121  auto &I = Result.first->second;
122  if (Result.second) {
123  Vector.push_back(std::make_pair(KV.first, KV.second));
124  I = Vector.size() - 1;
125  return std::make_pair(std::prev(end()), true);
126  }
127  return std::make_pair(begin() + I, false);
128  }
129 
130  std::pair<iterator, bool> insert(std::pair<KeyT, ValueT> &&KV) {
131  // Copy KV.first into the map, then move it into the vector.
132  std::pair<KeyT, typename MapType::mapped_type> Pair = std::make_pair(KV.first, 0);
133  std::pair<typename MapType::iterator, bool> Result = Map.insert(Pair);
134  auto &I = Result.first->second;
135  if (Result.second) {
136  Vector.push_back(std::move(KV));
137  I = Vector.size() - 1;
138  return std::make_pair(std::prev(end()), true);
139  }
140  return std::make_pair(begin() + I, false);
141  }
142 
143  size_type count(const KeyT &Key) const {
144  typename MapType::const_iterator Pos = Map.find(Key);
145  return Pos == Map.end()? 0 : 1;
146  }
147 
148  iterator find(const KeyT &Key) {
149  typename MapType::const_iterator Pos = Map.find(Key);
150  return Pos == Map.end()? Vector.end() :
151  (Vector.begin() + Pos->second);
152  }
153 
154  const_iterator find(const KeyT &Key) const {
155  typename MapType::const_iterator Pos = Map.find(Key);
156  return Pos == Map.end()? Vector.end() :
157  (Vector.begin() + Pos->second);
158  }
159 
160  /// Remove the last element from the vector.
161  void pop_back() {
162  typename MapType::iterator Pos = Map.find(Vector.back().first);
163  Map.erase(Pos);
164  Vector.pop_back();
165  }
166 
167  /// Remove the element given by Iterator.
168  ///
169  /// Returns an iterator to the element following the one which was removed,
170  /// which may be end().
171  ///
172  /// \note This is a deceivingly expensive operation (linear time). It's
173  /// usually better to use \a remove_if() if possible.
174  typename VectorType::iterator erase(typename VectorType::iterator Iterator) {
175  Map.erase(Iterator->first);
176  auto Next = Vector.erase(Iterator);
177  if (Next == Vector.end())
178  return Next;
179 
180  // Update indices in the map.
181  size_t Index = Next - Vector.begin();
182  for (auto &I : Map) {
183  assert(I.second != Index && "Index was already erased!");
184  if (I.second > Index)
185  --I.second;
186  }
187  return Next;
188  }
189 
190  /// Remove all elements with the key value Key.
191  ///
192  /// Returns the number of elements removed.
193  size_type erase(const KeyT &Key) {
194  auto Iterator = find(Key);
195  if (Iterator == end())
196  return 0;
197  erase(Iterator);
198  return 1;
199  }
200 
201  /// Remove the elements that match the predicate.
202  ///
203  /// Erase all elements that match \c Pred in a single pass. Takes linear
204  /// time.
205  template <class Predicate> void remove_if(Predicate Pred);
206 };
207 
208 template <typename KeyT, typename ValueT, typename MapType, typename VectorType>
209 template <class Function>
211  auto O = Vector.begin();
212  for (auto I = O, E = Vector.end(); I != E; ++I) {
213  if (Pred(*I)) {
214  // Erase from the map.
215  Map.erase(I->first);
216  continue;
217  }
218 
219  if (I != O) {
220  // Move the value and update the index in the map.
221  *O = std::move(*I);
222  Map[O->first] = O - Vector.begin();
223  }
224  ++O;
225  }
226  // Erase trailing entries in the vector.
227  Vector.erase(O, Vector.end());
228 }
229 
230 /// A MapVector that performs no allocations if smaller than a certain
231 /// size.
232 template <typename KeyT, typename ValueT, unsigned N>
234  : MapVector<KeyT, ValueT, SmallDenseMap<KeyT, unsigned, N>,
235  SmallVector<std::pair<KeyT, ValueT>, N>> {
236 };
237 
238 } // end namespace llvm
239 
240 #endif // LLVM_ADT_MAPVECTOR_H
const_iterator begin() const
Definition: MapVector.h:71
void clear()
Definition: MapVector.h:89
const_reverse_iterator rend() const
Definition: MapVector.h:78
size_type size() const
Definition: MapVector.h:61
This class represents lattice values for constants.
Definition: AllocatorList.h:24
reverse_iterator rend()
Definition: MapVector.h:77
void pop_back()
Remove the last element from the vector.
Definition: MapVector.h:161
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:174
std::pair< KeyT, ValueT > & back()
Definition: MapVector.h:86
A MapVector that performs no allocations if smaller than a certain size.
Definition: MapVector.h:233
ValueT & operator[](const KeyT &Key)
Definition: MapVector.h:99
bool empty() const
Definition: MapVector.h:80
Key
PAL metadata keys.
typename std::vector< std::pair< AssertingVH< Instruction >, AssertingVH< Value > >> ::const_reverse_iterator const_reverse_iterator
Definition: MapVector.h:53
iterator find(const KeyT &Key)
Definition: MapVector.h:148
typename std::vector< std::pair< AssertingVH< Instruction >, AssertingVH< Value > >> ::reverse_iterator reverse_iterator
Definition: MapVector.h:52
typename std::vector< std::pair< AssertingVH< Instruction >, AssertingVH< Value > >> ::value_type value_type
Definition: MapVector.h:47
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:154
const std::pair< KeyT, ValueT > & back() const
Definition: MapVector.h:87
VectorType takeVector()
Clear the MapVector and return the underlying vector.
Definition: MapVector.h:56
std::pair< iterator, bool > insert(std::pair< KeyT, ValueT > &&KV)
Definition: MapVector.h:130
std::pair< iterator, bool > insert(const std::pair< KeyT, ValueT > &KV)
Definition: MapVector.h:118
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:51
size_type count(const KeyT &Key) const
Definition: MapVector.h:143
const std::pair< KeyT, ValueT > & front() const
Definition: MapVector.h:85
reverse_iterator rbegin()
Definition: MapVector.h:75
typename std::vector< std::pair< AssertingVH< Instruction >, AssertingVH< Value > >> ::iterator iterator
Definition: MapVector.h:50
void swap(llvm::BitVector &LHS, llvm::BitVector &RHS)
Implement std::swap in terms of BitVector swap.
Definition: BitVector.h:941
ValueT lookup(const KeyT &Key) const
Definition: MapVector.h:111
std::pair< KeyT, ValueT > & front()
Definition: MapVector.h:84
void reserve(size_type NumEntries)
Grow the MapVector so that it can contain at least NumEntries items before resizing again...
Definition: MapVector.h:65
const_reverse_iterator rbegin() const
Definition: MapVector.h:76
#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:193
iterator begin()
Definition: MapVector.h:70
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
iterator end()
Definition: MapVector.h:72
typename std::vector< std::pair< AssertingVH< Instruction >, AssertingVH< Value > >> ::size_type size_type
Definition: MapVector.h:48
const_iterator end() const
Definition: MapVector.h:73
void swap(MapVector &RHS)
Definition: MapVector.h:94