include/llvm/ADT/ImmutableMap.h

   1 //===--- ImmutableMap.h - Immutable (functional) map interface --*- 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 defines the ImmutableMap class.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #ifndef LLVM_ADT_IMMUTABLEMAP_H
  14 #define LLVM_ADT_IMMUTABLEMAP_H
  15
  16 #include "llvm/ADT/FoldingSet.h"
  17 #include "llvm/ADT/ImmutableSet.h"
  18 #include "llvm/Support/Allocator.h"
  19 #include <utility>
  20
  21 namespace llvm {
  22
  23 /// ImutKeyValueInfo -Traits class used by ImmutableMap.  While both the first
  24 /// and second elements in a pair are used to generate profile information,
  25 /// only the first element (the key) is used by isEqual and isLess.
  26 template <typename T, typename S>
  27 struct ImutKeyValueInfo {
  28   using value_type = const std::pair<T,S>;
  29   using value_type_ref = const value_type&;
  30   using key_type = const T;
  31   using key_type_ref = const T&;
  32   using data_type = const S;
  33   using data_type_ref = const S&;
  34
  35   static inline key_type_ref KeyOfValue(value_type_ref V) {
  36     return V.first;
  37   }
  38
  39   static inline data_type_ref DataOfValue(value_type_ref V) {
  40     return V.second;
  41   }
  42
  43   static inline bool isEqual(key_type_ref L, key_type_ref R) {
  44     return ImutContainerInfo<T>::isEqual(L,R);
  45   }
  46   static inline bool isLess(key_type_ref L, key_type_ref R) {
  47     return ImutContainerInfo<T>::isLess(L,R);
  48   }
  49
  50   static inline bool isDataEqual(data_type_ref L, data_type_ref R) {
  51     return ImutContainerInfo<S>::isEqual(L,R);
  52   }
  53
  54   static inline void Profile(FoldingSetNodeID& ID, value_type_ref V) {
  55     ImutContainerInfo<T>::Profile(ID, V.first);
  56     ImutContainerInfo<S>::Profile(ID, V.second);
  57   }
  58 };
  59
  60 template <typename KeyT, typename ValT,
  61           typename ValInfo = ImutKeyValueInfo<KeyT,ValT>>
  62 class ImmutableMap {
  63 public:
  64   using value_type = typename ValInfo::value_type;
  65   using value_type_ref = typename ValInfo::value_type_ref;
  66   using key_type = typename ValInfo::key_type;
  67   using key_type_ref = typename ValInfo::key_type_ref;
  68   using data_type = typename ValInfo::data_type;
  69   using data_type_ref = typename ValInfo::data_type_ref;
  70   using TreeTy = ImutAVLTree<ValInfo>;
  71
  72 protected:
  73   TreeTy* Root;
  74
  75 public:
  76   /// Constructs a map from a pointer to a tree root.  In general one
  77   /// should use a Factory object to create maps instead of directly
  78   /// invoking the constructor, but there are cases where make this
  79   /// constructor public is useful.
  80   explicit ImmutableMap(const TreeTy* R) : Root(const_cast<TreeTy*>(R)) {
  81     if (Root) { Root->retain(); }
  82   }
  83
  84   ImmutableMap(const ImmutableMap &X) : Root(X.Root) {
  85     if (Root) { Root->retain(); }
  86   }
  87
  88   ~ImmutableMap() {
  89     if (Root) { Root->release(); }
  90   }
  91
  92   ImmutableMap &operator=(const ImmutableMap &X) {
  93     if (Root != X.Root) {
  94       if (X.Root) { X.Root->retain(); }
  95       if (Root) { Root->release(); }
  96       Root = X.Root;
  97     }
  98     return *this;
  99   }
 100
 101   class Factory {
 102     typename TreeTy::Factory F;
 103     const bool Canonicalize;
 104
 105   public:
 106     Factory(bool canonicalize = true) : Canonicalize(canonicalize) {}
 107
 108     Factory(BumpPtrAllocator &Alloc, bool canonicalize = true)
 109         : F(Alloc), Canonicalize(canonicalize) {}
 110
 111     Factory(const Factory &) = delete;
 112     Factory &operator=(const Factory &) = delete;
 113
 114     ImmutableMap getEmptyMap() { return ImmutableMap(F.getEmptyTree()); }
 115
 116     LLVM_NODISCARD ImmutableMap add(ImmutableMap Old, key_type_ref K,
 117                                     data_type_ref D) {
 118       TreeTy *T = F.add(Old.Root, std::pair<key_type,data_type>(K,D));
 119       return ImmutableMap(Canonicalize ? F.getCanonicalTree(T): T);
 120     }
 121
 122     LLVM_NODISCARD ImmutableMap remove(ImmutableMap Old, key_type_ref K) {
 123       TreeTy *T = F.remove(Old.Root,K);
 124       return ImmutableMap(Canonicalize ? F.getCanonicalTree(T): T);
 125     }
 126
 127     typename TreeTy::Factory *getTreeFactory() const {
 128       return const_cast<typename TreeTy::Factory *>(&F);
 129     }
 130   };
 131
 132   bool contains(key_type_ref K) const {
 133     return Root ? Root->contains(K) : false;
 134   }
 135
 136   bool operator==(const ImmutableMap &RHS) const {
 137     return Root && RHS.Root ? Root->isEqual(*RHS.Root) : Root == RHS.Root;
 138   }
 139
 140   bool operator!=(const ImmutableMap &RHS) const {
 141     return Root && RHS.Root ? Root->isNotEqual(*RHS.Root) : Root != RHS.Root;
 142   }
 143
 144   TreeTy *getRoot() const {
 145     if (Root) { Root->retain(); }
 146     return Root;
 147   }
 148
 149   TreeTy *getRootWithoutRetain() const { return Root; }
 150
 151   void manualRetain() {
 152     if (Root) Root->retain();
 153   }
 154
 155   void manualRelease() {
 156     if (Root) Root->release();
 157   }
 158
 159   bool isEmpty() const { return !Root; }
 160
 161   //===--------------------------------------------------===//
 162   // Foreach - A limited form of map iteration.
 163   //===--------------------------------------------------===//
 164
 165 private:
 166   template <typename Callback>
 167   struct CBWrapper {
 168     Callback C;
 169
 170     void operator()(value_type_ref V) { C(V.first,V.second); }
 171   };
 172
 173   template <typename Callback>
 174   struct CBWrapperRef {
 175     Callback &C;
 176
 177     CBWrapperRef(Callback& c) : C(c) {}
 178
 179     void operator()(value_type_ref V) { C(V.first,V.second); }
 180   };
 181
 182 public:
 183   template <typename Callback>
 184   void foreach(Callback& C) {
 185     if (Root) {
 186       CBWrapperRef<Callback> CB(C);
 187       Root->foreach(CB);
 188     }
 189   }
 190
 191   template <typename Callback>
 192   void foreach() {
 193     if (Root) {
 194       CBWrapper<Callback> CB;
 195       Root->foreach(CB);
 196     }
 197   }
 198
 199   //===--------------------------------------------------===//
 200   // For testing.
 201   //===--------------------------------------------------===//
 202
 203   void verify() const { if (Root) Root->verify(); }
 204
 205   //===--------------------------------------------------===//
 206   // Iterators.
 207   //===--------------------------------------------------===//
 208
 209   class iterator : public ImutAVLValueIterator<ImmutableMap> {
 210     friend class ImmutableMap;
 211
 212     iterator() = default;
 213     explicit iterator(TreeTy *Tree) : iterator::ImutAVLValueIterator(Tree) {}
 214
 215   public:
 216     key_type_ref getKey() const { return (*this)->first; }
 217     data_type_ref getData() const { return (*this)->second; }
 218   };
 219
 220   iterator begin() const { return iterator(Root); }
 221   iterator end() const { return iterator(); }
 222
 223   data_type* lookup(key_type_ref K) const {
 224     if (Root) {
 225       TreeTy* T = Root->find(K);
 226       if (T) return &T->getValue().second;
 227     }
 228
 229     return nullptr;
 230   }
 231
 232   /// getMaxElement - Returns the <key,value> pair in the ImmutableMap for
 233   ///  which key is the highest in the ordering of keys in the map.  This
 234   ///  method returns NULL if the map is empty.
 235   value_type* getMaxElement() const {
 236     return Root ? &(Root->getMaxElement()->getValue()) : nullptr;
 237   }
 238
 239   //===--------------------------------------------------===//
 240   // Utility methods.
 241   //===--------------------------------------------------===//
 242
 243   unsigned getHeight() const { return Root ? Root->getHeight() : 0; }
 244
 245   static inline void Profile(FoldingSetNodeID& ID, const ImmutableMap& M) {
 246     ID.AddPointer(M.Root);
 247   }
 248
 249   inline void Profile(FoldingSetNodeID& ID) const {
 250     return Profile(ID,*this);
 251   }
 252 };
 253
 254 // NOTE: This will possibly become the new implementation of ImmutableMap some day.
 255 template <typename KeyT, typename ValT,
 256 typename ValInfo = ImutKeyValueInfo<KeyT,ValT>>
 257 class ImmutableMapRef {
 258 public:
 259   using value_type = typename ValInfo::value_type;
 260   using value_type_ref = typename ValInfo::value_type_ref;
 261   using key_type = typename ValInfo::key_type;
 262   using key_type_ref = typename ValInfo::key_type_ref;
 263   using data_type = typename ValInfo::data_type;
 264   using data_type_ref = typename ValInfo::data_type_ref;
 265   using TreeTy = ImutAVLTree<ValInfo>;
 266   using FactoryTy = typename TreeTy::Factory;
 267
 268 protected:
 269   TreeTy *Root;
 270   FactoryTy *Factory;
 271
 272 public:
 273   /// Constructs a map from a pointer to a tree root.  In general one
 274   /// should use a Factory object to create maps instead of directly
 275   /// invoking the constructor, but there are cases where make this
 276   /// constructor public is useful.
 277   explicit ImmutableMapRef(const TreeTy *R, FactoryTy *F)
 278       : Root(const_cast<TreeTy *>(R)), Factory(F) {
 279     if (Root) {
 280       Root->retain();
 281     }
 282   }
 283
 284   explicit ImmutableMapRef(const ImmutableMap<KeyT, ValT> &X,
 285                            typename ImmutableMap<KeyT, ValT>::Factory &F)
 286     : Root(X.getRootWithoutRetain()),
 287       Factory(F.getTreeFactory()) {
 288     if (Root) { Root->retain(); }
 289   }
 290
 291   ImmutableMapRef(const ImmutableMapRef &X) : Root(X.Root), Factory(X.Factory) {
 292     if (Root) {
 293       Root->retain();
 294     }
 295   }
 296
 297   ~ImmutableMapRef() {
 298     if (Root)
 299       Root->release();
 300   }
 301
 302   ImmutableMapRef &operator=(const ImmutableMapRef &X) {
 303     if (Root != X.Root) {
 304       if (X.Root)
 305         X.Root->retain();
 306
 307       if (Root)
 308         Root->release();
 309
 310       Root = X.Root;
 311       Factory = X.Factory;
 312     }
 313     return *this;
 314   }
 315
 316   static inline ImmutableMapRef getEmptyMap(FactoryTy *F) {
 317     return ImmutableMapRef(0, F);
 318   }
 319
 320   void manualRetain() {
 321     if (Root) Root->retain();
 322   }
 323
 324   void manualRelease() {
 325     if (Root) Root->release();
 326   }
 327
 328   ImmutableMapRef add(key_type_ref K, data_type_ref D) const {
 329     TreeTy *NewT = Factory->add(Root, std::pair<key_type, data_type>(K, D));
 330     return ImmutableMapRef(NewT, Factory);
 331   }
 332
 333   ImmutableMapRef remove(key_type_ref K) const {
 334     TreeTy *NewT = Factory->remove(Root, K);
 335     return ImmutableMapRef(NewT, Factory);
 336   }
 337
 338   bool contains(key_type_ref K) const {
 339     return Root ? Root->contains(K) : false;
 340   }
 341
 342   ImmutableMap<KeyT, ValT> asImmutableMap() const {
 343     return ImmutableMap<KeyT, ValT>(Factory->getCanonicalTree(Root));
 344   }
 345
 346   bool operator==(const ImmutableMapRef &RHS) const {
 347     return Root && RHS.Root ? Root->isEqual(*RHS.Root) : Root == RHS.Root;
 348   }
 349
 350   bool operator!=(const ImmutableMapRef &RHS) const {
 351     return Root && RHS.Root ? Root->isNotEqual(*RHS.Root) : Root != RHS.Root;
 352   }
 353
 354   bool isEmpty() const { return !Root; }
 355
 356   //===--------------------------------------------------===//
 357   // For testing.
 358   //===--------------------------------------------------===//
 359
 360   void verify() const {
 361     if (Root)
 362       Root->verify();
 363   }
 364
 365   //===--------------------------------------------------===//
 366   // Iterators.
 367   //===--------------------------------------------------===//
 368
 369   class iterator : public ImutAVLValueIterator<ImmutableMapRef> {
 370     friend class ImmutableMapRef;
 371
 372     iterator() = default;
 373     explicit iterator(TreeTy *Tree) : iterator::ImutAVLValueIterator(Tree) {}
 374
 375   public:
 376     key_type_ref getKey() const { return (*this)->first; }
 377     data_type_ref getData() const { return (*this)->second; }
 378   };
 379
 380   iterator begin() const { return iterator(Root); }
 381   iterator end() const { return iterator(); }
 382
 383   data_type *lookup(key_type_ref K) const {
 384     if (Root) {
 385       TreeTy* T = Root->find(K);
 386       if (T) return &T->getValue().second;
 387     }
 388
 389     return nullptr;
 390   }
 391
 392   /// getMaxElement - Returns the <key,value> pair in the ImmutableMap for
 393   ///  which key is the highest in the ordering of keys in the map.  This
 394   ///  method returns NULL if the map is empty.
 395   value_type* getMaxElement() const {
 396     return Root ? &(Root->getMaxElement()->getValue()) : 0;
 397   }
 398
 399   //===--------------------------------------------------===//
 400   // Utility methods.
 401   //===--------------------------------------------------===//
 402
 403   unsigned getHeight() const { return Root ? Root->getHeight() : 0; }
 404
 405   static inline void Profile(FoldingSetNodeID &ID, const ImmutableMapRef &M) {
 406     ID.AddPointer(M.Root);
 407   }
 408
 409   inline void Profile(FoldingSetNodeID &ID) const { return Profile(ID, *this); }
 410 };
 411
 412 } // end namespace llvm
 413
 414 #endif // LLVM_ADT_IMMUTABLEMAP_H