1 //===- llvm/ADT/DenseSet.h - Dense probed hash table ------------*- 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 defines the DenseSet and SmallDenseSet classes. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_ADT_DENSESET_H 15 #define LLVM_ADT_DENSESET_H 16 17 #include "llvm/ADT/DenseMap.h" 18 #include "llvm/ADT/DenseMapInfo.h" 19 #include "llvm/Support/type_traits.h" 20 #include <algorithm> 21 #include <cstddef> 22 #include <initializer_list> 23 #include <iterator> 24 #include <utility> 25 26 namespace llvm { 27 28 namespace detail { 29 30 struct DenseSetEmpty {}; 31 32 // Use the empty base class trick so we can create a DenseMap where the buckets 33 // contain only a single item. 34 template <typename KeyT> class DenseSetPair : public DenseSetEmpty { 35 KeyT key; 36 37 public: 38 KeyT &getFirst() { return key; } 39 const KeyT &getFirst() const { return key; } 40 DenseSetEmpty &getSecond() { return *this; } 41 const DenseSetEmpty &getSecond() const { return *this; } 42 }; 43 44 /// Base class for DenseSet and DenseSmallSet. 45 /// 46 /// MapTy should be either 47 /// 48 /// DenseMap<ValueT, detail::DenseSetEmpty, ValueInfoT, 49 /// detail::DenseSetPair<ValueT>> 50 /// 51 /// or the equivalent SmallDenseMap type. ValueInfoT must implement the 52 /// DenseMapInfo "concept". 53 template <typename ValueT, typename MapTy, typename ValueInfoT> 54 class DenseSetImpl { 55 static_assert(sizeof(typename MapTy::value_type) == sizeof(ValueT), 56 "DenseMap buckets unexpectedly large!"); 57 MapTy TheMap; 58 59 template <typename T> 60 using const_arg_type_t = typename const_pointer_or_const_ref<T>::type; 61 62 public: 63 using key_type = ValueT; 64 using value_type = ValueT; 65 using size_type = unsigned; 66 67 explicit DenseSetImpl(unsigned InitialReserve = 0) : TheMap(InitialReserve) {} 68 69 DenseSetImpl(std::initializer_list<ValueT> Elems) 70 : DenseSetImpl(Elems.size()) { 71 insert(Elems.begin(), Elems.end()); 72 } 73 74 bool empty() const { return TheMap.empty(); } 75 size_type size() const { return TheMap.size(); } 76 size_t getMemorySize() const { return TheMap.getMemorySize(); } 77 78 /// Grow the DenseSet so that it has at least Size buckets. Will not shrink 79 /// the Size of the set. 80 void resize(size_t Size) { TheMap.resize(Size); } 81 82 /// Grow the DenseSet so that it can contain at least \p NumEntries items 83 /// before resizing again. 84 void reserve(size_t Size) { TheMap.reserve(Size); } 85 86 void clear() { 87 TheMap.clear(); 88 } 89 90 /// Return 1 if the specified key is in the set, 0 otherwise. 91 size_type count(const_arg_type_t<ValueT> V) const { 92 return TheMap.count(V); 93 } 94 95 bool erase(const ValueT &V) { 96 return TheMap.erase(V); 97 } 98 99 void swap(DenseSetImpl &RHS) { TheMap.swap(RHS.TheMap); } 100 101 // Iterators. 102 103 class ConstIterator; 104 105 class Iterator { 106 typename MapTy::iterator I; 107 friend class DenseSetImpl; 108 friend class ConstIterator; 109 110 public: 111 using difference_type = typename MapTy::iterator::difference_type; 112 using value_type = ValueT; 113 using pointer = value_type *; 114 using reference = value_type &; 115 using iterator_category = std::forward_iterator_tag; 116 117 Iterator() = default; 118 Iterator(const typename MapTy::iterator &i) : I(i) {} 119 120 ValueT &operator*() { return I->getFirst(); } 121 const ValueT &operator*() const { return I->getFirst(); } 122 ValueT *operator->() { return &I->getFirst(); } 123 const ValueT *operator->() const { return &I->getFirst(); } 124 125 Iterator& operator++() { ++I; return *this; } 126 Iterator operator++(int) { auto T = *this; ++I; return T; } 127 bool operator==(const ConstIterator& X) const { return I == X.I; } 128 bool operator!=(const ConstIterator& X) const { return I != X.I; } 129 }; 130 131 class ConstIterator { 132 typename MapTy::const_iterator I; 133 friend class DenseSet; 134 friend class Iterator; 135 136 public: 137 using difference_type = typename MapTy::const_iterator::difference_type; 138 using value_type = ValueT; 139 using pointer = value_type *; 140 using reference = value_type &; 141 using iterator_category = std::forward_iterator_tag; 142 143 ConstIterator() = default; 144 ConstIterator(const Iterator &B) : I(B.I) {} 145 ConstIterator(const typename MapTy::const_iterator &i) : I(i) {} 146 147 const ValueT &operator*() const { return I->getFirst(); } 148 const ValueT *operator->() const { return &I->getFirst(); } 149 150 ConstIterator& operator++() { ++I; return *this; } 151 ConstIterator operator++(int) { auto T = *this; ++I; return T; } 152 bool operator==(const ConstIterator& X) const { return I == X.I; } 153 bool operator!=(const ConstIterator& X) const { return I != X.I; } 154 }; 155 156 using iterator = Iterator; 157 using const_iterator = ConstIterator; 158 159 iterator begin() { return Iterator(TheMap.begin()); } 160 iterator end() { return Iterator(TheMap.end()); } 161 162 const_iterator begin() const { return ConstIterator(TheMap.begin()); } 163 const_iterator end() const { return ConstIterator(TheMap.end()); } 164 165 iterator find(const_arg_type_t<ValueT> V) { return Iterator(TheMap.find(V)); } 166 const_iterator find(const_arg_type_t<ValueT> V) const { 167 return ConstIterator(TheMap.find(V)); 168 } 169 170 /// Alternative version of find() which allows a different, and possibly less 171 /// expensive, key type. 172 /// The DenseMapInfo is responsible for supplying methods 173 /// getHashValue(LookupKeyT) and isEqual(LookupKeyT, KeyT) for each key type 174 /// used. 175 template <class LookupKeyT> 176 iterator find_as(const LookupKeyT &Val) { 177 return Iterator(TheMap.find_as(Val)); 178 } 179 template <class LookupKeyT> 180 const_iterator find_as(const LookupKeyT &Val) const { 181 return ConstIterator(TheMap.find_as(Val)); 182 } 183 184 void erase(Iterator I) { return TheMap.erase(I.I); } 185 void erase(ConstIterator CI) { return TheMap.erase(CI.I); } 186 187 std::pair<iterator, bool> insert(const ValueT &V) { 188 detail::DenseSetEmpty Empty; 189 return TheMap.try_emplace(V, Empty); 190 } 191 192 std::pair<iterator, bool> insert(ValueT &&V) { 193 detail::DenseSetEmpty Empty; 194 return TheMap.try_emplace(std::move(V), Empty); 195 } 196 197 /// Alternative version of insert that uses a different (and possibly less 198 /// expensive) key type. 199 template <typename LookupKeyT> 200 std::pair<iterator, bool> insert_as(const ValueT &V, 201 const LookupKeyT &LookupKey) { 202 return TheMap.insert_as({V, detail::DenseSetEmpty()}, LookupKey); 203 } 204 template <typename LookupKeyT> 205 std::pair<iterator, bool> insert_as(ValueT &&V, const LookupKeyT &LookupKey) { 206 return TheMap.insert_as({std::move(V), detail::DenseSetEmpty()}, LookupKey); 207 } 208 209 // Range insertion of values. 210 template<typename InputIt> 211 void insert(InputIt I, InputIt E) { 212 for (; I != E; ++I) 213 insert(*I); 214 } 215 }; 216 217 } // end namespace detail 218 219 /// Implements a dense probed hash-table based set. 220 template <typename ValueT, typename ValueInfoT = DenseMapInfo<ValueT>> 221 class DenseSet : public detail::DenseSetImpl< 222 ValueT, DenseMap<ValueT, detail::DenseSetEmpty, ValueInfoT, 223 detail::DenseSetPair<ValueT>>, 224 ValueInfoT> { 225 using BaseT = 226 detail::DenseSetImpl<ValueT, 227 DenseMap<ValueT, detail::DenseSetEmpty, ValueInfoT, 228 detail::DenseSetPair<ValueT>>, 229 ValueInfoT>; 230 231 public: 232 using BaseT::BaseT; 233 }; 234 235 /// Implements a dense probed hash-table based set with some number of buckets 236 /// stored inline. 237 template <typename ValueT, unsigned InlineBuckets = 4, 238 typename ValueInfoT = DenseMapInfo<ValueT>> 239 class SmallDenseSet 240 : public detail::DenseSetImpl< 241 ValueT, SmallDenseMap<ValueT, detail::DenseSetEmpty, InlineBuckets, 242 ValueInfoT, detail::DenseSetPair<ValueT>>, 243 ValueInfoT> { 244 using BaseT = detail::DenseSetImpl< 245 ValueT, SmallDenseMap<ValueT, detail::DenseSetEmpty, InlineBuckets, 246 ValueInfoT, detail::DenseSetPair<ValueT>>, 247 ValueInfoT>; 248 249 public: 250 using BaseT::BaseT; 251 }; 252 253 } // end namespace llvm 254 255 #endif // LLVM_ADT_DENSESET_H 256
