LLVM  10.0.0svn
MapVector.h
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1 //===- llvm/ADT/MapVector.h - Map w/ deterministic value order --*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements a map that provides insertion order iteration. The
10 // interface is purposefully minimal. The key is assumed to be cheap to copy
11 // and 2 copies are kept, one for indexing in a DenseMap, one for iteration in
12 // a std::vector.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #ifndef LLVM_ADT_MAPVECTOR_H
17 #define LLVM_ADT_MAPVECTOR_H
18 
19 #include "llvm/ADT/DenseMap.h"
20 #include "llvm/ADT/SmallVector.h"
21 #include <algorithm>
22 #include <cassert>
23 #include <cstddef>
24 #include <iterator>
25 #include <type_traits>
26 #include <utility>
27 #include <vector>
28 
29 namespace llvm {
30 
31 /// This class implements a map that also provides access to all stored values
32 /// in a deterministic order. The values are kept in a std::vector and the
33 /// mapping is done with DenseMap from Keys to indexes in that vector.
34 template<typename KeyT, typename ValueT,
35  typename MapType = DenseMap<KeyT, unsigned>,
36  typename VectorType = std::vector<std::pair<KeyT, ValueT>>>
37 class MapVector {
38  MapType Map;
39  VectorType Vector;
40 
41  static_assert(
42  std::is_integral<typename MapType::mapped_type>::value,
43  "The mapped_type of the specified Map must be an integral type");
44 
45 public:
46  using value_type = typename VectorType::value_type;
47  using size_type = typename VectorType::size_type;
48 
49  using iterator = typename VectorType::iterator;
50  using const_iterator = typename VectorType::const_iterator;
51  using reverse_iterator = typename VectorType::reverse_iterator;
52  using const_reverse_iterator = typename VectorType::const_reverse_iterator;
53 
54  /// Clear the MapVector and return the underlying vector.
55  VectorType takeVector() {
56  Map.clear();
57  return std::move(Vector);
58  }
59 
60  size_type size() const { return Vector.size(); }
61 
62  /// Grow the MapVector so that it can contain at least \p NumEntries items
63  /// before resizing again.
64  void reserve(size_type NumEntries) {
65  Map.reserve(NumEntries);
66  Vector.reserve(NumEntries);
67  }
68 
69  iterator begin() { return Vector.begin(); }
70  const_iterator begin() const { return Vector.begin(); }
71  iterator end() { return Vector.end(); }
72  const_iterator end() const { return Vector.end(); }
73 
74  reverse_iterator rbegin() { return Vector.rbegin(); }
75  const_reverse_iterator rbegin() const { return Vector.rbegin(); }
76  reverse_iterator rend() { return Vector.rend(); }
77  const_reverse_iterator rend() const { return Vector.rend(); }
78 
79  bool empty() const {
80  return Vector.empty();
81  }
82 
83  std::pair<KeyT, ValueT> &front() { return Vector.front(); }
84  const std::pair<KeyT, ValueT> &front() const { return Vector.front(); }
85  std::pair<KeyT, ValueT> &back() { return Vector.back(); }
86  const std::pair<KeyT, ValueT> &back() const { return Vector.back(); }
87 
88  void clear() {
89  Map.clear();
90  Vector.clear();
91  }
92 
93  void swap(MapVector &RHS) {
94  std::swap(Map, RHS.Map);
95  std::swap(Vector, RHS.Vector);
96  }
97 
98  ValueT &operator[](const KeyT &Key) {
99  std::pair<KeyT, typename MapType::mapped_type> Pair = std::make_pair(Key, 0);
100  std::pair<typename MapType::iterator, bool> Result = Map.insert(Pair);
101  auto &I = Result.first->second;
102  if (Result.second) {
103  Vector.push_back(std::make_pair(Key, ValueT()));
104  I = Vector.size() - 1;
105  }
106  return Vector[I].second;
107  }
108 
109  // Returns a copy of the value. Only allowed if ValueT is copyable.
110  ValueT lookup(const KeyT &Key) const {
111  static_assert(std::is_copy_constructible<ValueT>::value,
112  "Cannot call lookup() if ValueT is not copyable.");
113  typename MapType::const_iterator Pos = Map.find(Key);
114  return Pos == Map.end()? ValueT() : Vector[Pos->second].second;
115  }
116 
117  std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &KV) {
118  std::pair<KeyT, typename MapType::mapped_type> Pair = std::make_pair(KV.first, 0);
119  std::pair<typename MapType::iterator, bool> Result = Map.insert(Pair);
120  auto &I = Result.first->second;
121  if (Result.second) {
122  Vector.push_back(std::make_pair(KV.first, KV.second));
123  I = Vector.size() - 1;
124  return std::make_pair(std::prev(end()), true);
125  }
126  return std::make_pair(begin() + I, false);
127  }
128 
129  std::pair<iterator, bool> insert(std::pair<KeyT, ValueT> &&KV) {
130  // Copy KV.first into the map, then move it into the vector.
131  std::pair<KeyT, typename MapType::mapped_type> Pair = std::make_pair(KV.first, 0);
132  std::pair<typename MapType::iterator, bool> Result = Map.insert(Pair);
133  auto &I = Result.first->second;
134  if (Result.second) {
135  Vector.push_back(std::move(KV));
136  I = Vector.size() - 1;
137  return std::make_pair(std::prev(end()), true);
138  }
139  return std::make_pair(begin() + I, false);
140  }
141 
142  size_type count(const KeyT &Key) const {
143  typename MapType::const_iterator Pos = Map.find(Key);
144  return Pos == Map.end()? 0 : 1;
145  }
146 
147  iterator find(const KeyT &Key) {
148  typename MapType::const_iterator Pos = Map.find(Key);
149  return Pos == Map.end()? Vector.end() :
150  (Vector.begin() + Pos->second);
151  }
152 
153  const_iterator find(const KeyT &Key) const {
154  typename MapType::const_iterator Pos = Map.find(Key);
155  return Pos == Map.end()? Vector.end() :
156  (Vector.begin() + Pos->second);
157  }
158 
159  /// Remove the last element from the vector.
160  void pop_back() {
161  typename MapType::iterator Pos = Map.find(Vector.back().first);
162  Map.erase(Pos);
163  Vector.pop_back();
164  }
165 
166  /// Remove the element given by Iterator.
167  ///
168  /// Returns an iterator to the element following the one which was removed,
169  /// which may be end().
170  ///
171  /// \note This is a deceivingly expensive operation (linear time). It's
172  /// usually better to use \a remove_if() if possible.
173  typename VectorType::iterator erase(typename VectorType::iterator Iterator) {
174  Map.erase(Iterator->first);
175  auto Next = Vector.erase(Iterator);
176  if (Next == Vector.end())
177  return Next;
178 
179  // Update indices in the map.
180  size_t Index = Next - Vector.begin();
181  for (auto &I : Map) {
182  assert(I.second != Index && "Index was already erased!");
183  if (I.second > Index)
184  --I.second;
185  }
186  return Next;
187  }
188 
189  /// Remove all elements with the key value Key.
190  ///
191  /// Returns the number of elements removed.
192  size_type erase(const KeyT &Key) {
193  auto Iterator = find(Key);
194  if (Iterator == end())
195  return 0;
196  erase(Iterator);
197  return 1;
198  }
199 
200  /// Remove the elements that match the predicate.
201  ///
202  /// Erase all elements that match \c Pred in a single pass. Takes linear
203  /// time.
204  template <class Predicate> void remove_if(Predicate Pred);
205 };
206 
207 template <typename KeyT, typename ValueT, typename MapType, typename VectorType>
208 template <class Function>
210  auto O = Vector.begin();
211  for (auto I = O, E = Vector.end(); I != E; ++I) {
212  if (Pred(*I)) {
213  // Erase from the map.
214  Map.erase(I->first);
215  continue;
216  }
217 
218  if (I != O) {
219  // Move the value and update the index in the map.
220  *O = std::move(*I);
221  Map[O->first] = O - Vector.begin();
222  }
223  ++O;
224  }
225  // Erase trailing entries in the vector.
226  Vector.erase(O, Vector.end());
227 }
228 
229 /// A MapVector that performs no allocations if smaller than a certain
230 /// size.
231 template <typename KeyT, typename ValueT, unsigned N>
233  : MapVector<KeyT, ValueT, SmallDenseMap<KeyT, unsigned, N>,
234  SmallVector<std::pair<KeyT, ValueT>, N>> {
235 };
236 
237 } // end namespace llvm
238 
239 #endif // LLVM_ADT_MAPVECTOR_H
const_iterator begin() const
Definition: MapVector.h:70
void clear()
Definition: MapVector.h:88
const_reverse_iterator rend() const
Definition: MapVector.h:77
size_type size() const
Definition: MapVector.h:60
This class represents lattice values for constants.
Definition: AllocatorList.h:23
reverse_iterator rend()
Definition: MapVector.h:76
void pop_back()
Remove the last element from the vector.
Definition: MapVector.h:160
This class implements a map that also provides access to all stored values in a deterministic order...
Definition: MapVector.h:37
VectorType::iterator erase(typename VectorType::iterator Iterator)
Remove the element given by Iterator.
Definition: MapVector.h:173
std::pair< KeyT, ValueT > & back()
Definition: MapVector.h:85
A MapVector that performs no allocations if smaller than a certain size.
Definition: MapVector.h:232
ValueT & operator[](const KeyT &Key)
Definition: MapVector.h:98
bool empty() const
Definition: MapVector.h:79
Key
PAL metadata keys.
typename std::vector< std::pair< AssertingVH< Instruction >, AssertingVH< Value > >> ::const_reverse_iterator const_reverse_iterator
Definition: MapVector.h:52
iterator find(const KeyT &Key)
Definition: MapVector.h:147
typename std::vector< std::pair< AssertingVH< Instruction >, AssertingVH< Value > >> ::reverse_iterator reverse_iterator
Definition: MapVector.h:51
typename std::vector< std::pair< AssertingVH< Instruction >, AssertingVH< Value > >> ::value_type value_type
Definition: MapVector.h:46
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:153
const std::pair< KeyT, ValueT > & back() const
Definition: MapVector.h:86
VectorType takeVector()
Clear the MapVector and return the underlying vector.
Definition: MapVector.h:55
std::pair< iterator, bool > insert(std::pair< KeyT, ValueT > &&KV)
Definition: MapVector.h:129
std::pair< iterator, bool > insert(const std::pair< KeyT, ValueT > &KV)
Definition: MapVector.h:117
Predicate
Predicate - These are "(BI << 5) | BO" for various predicates.
Definition: PPCPredicates.h:26
typename std::vector< std::pair< AssertingVH< Instruction >, AssertingVH< Value > >> ::const_iterator const_iterator
Definition: MapVector.h:50
size_type count(const KeyT &Key) const
Definition: MapVector.h:142
const std::pair< KeyT, ValueT > & front() const
Definition: MapVector.h:84
reverse_iterator rbegin()
Definition: MapVector.h:74
typename std::vector< std::pair< AssertingVH< Instruction >, AssertingVH< Value > >> ::iterator iterator
Definition: MapVector.h:49
void swap(llvm::BitVector &LHS, llvm::BitVector &RHS)
Implement std::swap in terms of BitVector swap.
Definition: BitVector.h:940
ValueT lookup(const KeyT &Key) const
Definition: MapVector.h:110
std::pair< KeyT, ValueT > & front()
Definition: MapVector.h:83
void reserve(size_type NumEntries)
Grow the MapVector so that it can contain at least NumEntries items before resizing again...
Definition: MapVector.h:64
const_reverse_iterator rbegin() const
Definition: MapVector.h:75
#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:192
iterator begin()
Definition: MapVector.h:69
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
iterator end()
Definition: MapVector.h:71
typename std::vector< std::pair< AssertingVH< Instruction >, AssertingVH< Value > >> ::size_type size_type
Definition: MapVector.h:47
const_iterator end() const
Definition: MapVector.h:72
void swap(MapVector &RHS)
Definition: MapVector.h:93