1 //===- llvm/ADT/FoldingSet.h - Uniquing Hash Set ----------------*- 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 a hash set that can be used to remove duplication of nodes 10 // in a graph. This code was originally created by Chris Lattner for use with 11 // SelectionDAGCSEMap, but was isolated to provide use across the llvm code set. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_ADT_FOLDINGSET_H 16 #define LLVM_ADT_FOLDINGSET_H 17 18 #include "llvm/ADT/SmallVector.h" 19 #include "llvm/ADT/iterator.h" 20 #include "llvm/Support/Allocator.h" 21 #include <cassert> 22 #include <cstddef> 23 #include <cstdint> 24 #include <utility> 25 26 namespace llvm { 27 28 /// This folding set used for two purposes: 29 /// 1. Given information about a node we want to create, look up the unique 30 /// instance of the node in the set. If the node already exists, return 31 /// it, otherwise return the bucket it should be inserted into. 32 /// 2. Given a node that has already been created, remove it from the set. 33 /// 34 /// This class is implemented as a single-link chained hash table, where the 35 /// "buckets" are actually the nodes themselves (the next pointer is in the 36 /// node). The last node points back to the bucket to simplify node removal. 37 /// 38 /// Any node that is to be included in the folding set must be a subclass of 39 /// FoldingSetNode. The node class must also define a Profile method used to 40 /// establish the unique bits of data for the node. The Profile method is 41 /// passed a FoldingSetNodeID object which is used to gather the bits. Just 42 /// call one of the Add* functions defined in the FoldingSetBase::NodeID class. 43 /// NOTE: That the folding set does not own the nodes and it is the 44 /// responsibility of the user to dispose of the nodes. 45 /// 46 /// Eg. 47 /// class MyNode : public FoldingSetNode { 48 /// private: 49 /// std::string Name; 50 /// unsigned Value; 51 /// public: 52 /// MyNode(const char *N, unsigned V) : Name(N), Value(V) {} 53 /// ... 54 /// void Profile(FoldingSetNodeID &ID) const { 55 /// ID.AddString(Name); 56 /// ID.AddInteger(Value); 57 /// } 58 /// ... 59 /// }; 60 /// 61 /// To define the folding set itself use the FoldingSet template; 62 /// 63 /// Eg. 64 /// FoldingSet<MyNode> MyFoldingSet; 65 /// 66 /// Four public methods are available to manipulate the folding set; 67 /// 68 /// 1) If you have an existing node that you want add to the set but unsure 69 /// that the node might already exist then call; 70 /// 71 /// MyNode *M = MyFoldingSet.GetOrInsertNode(N); 72 /// 73 /// If The result is equal to the input then the node has been inserted. 74 /// Otherwise, the result is the node existing in the folding set, and the 75 /// input can be discarded (use the result instead.) 76 /// 77 /// 2) If you are ready to construct a node but want to check if it already 78 /// exists, then call FindNodeOrInsertPos with a FoldingSetNodeID of the bits to 79 /// check; 80 /// 81 /// FoldingSetNodeID ID; 82 /// ID.AddString(Name); 83 /// ID.AddInteger(Value); 84 /// void *InsertPoint; 85 /// 86 /// MyNode *M = MyFoldingSet.FindNodeOrInsertPos(ID, InsertPoint); 87 /// 88 /// If found then M will be non-NULL, else InsertPoint will point to where it 89 /// should be inserted using InsertNode. 90 /// 91 /// 3) If you get a NULL result from FindNodeOrInsertPos then you can insert a 92 /// new node with InsertNode; 93 /// 94 /// MyFoldingSet.InsertNode(M, InsertPoint); 95 /// 96 /// 4) Finally, if you want to remove a node from the folding set call; 97 /// 98 /// bool WasRemoved = MyFoldingSet.RemoveNode(M); 99 /// 100 /// The result indicates whether the node existed in the folding set. 101 102 class FoldingSetNodeID; 103 class StringRef; 104 105 //===----------------------------------------------------------------------===// 106 /// FoldingSetBase - Implements the folding set functionality. The main 107 /// structure is an array of buckets. Each bucket is indexed by the hash of 108 /// the nodes it contains. The bucket itself points to the nodes contained 109 /// in the bucket via a singly linked list. The last node in the list points 110 /// back to the bucket to facilitate node removal. 111 /// 112 class FoldingSetBase { 113 protected: 114 /// Buckets - Array of bucket chains. 115 void **Buckets; 116 117 /// NumBuckets - Length of the Buckets array. Always a power of 2. 118 unsigned NumBuckets; 119 120 /// NumNodes - Number of nodes in the folding set. Growth occurs when NumNodes 121 /// is greater than twice the number of buckets. 122 unsigned NumNodes; 123 124 explicit FoldingSetBase(unsigned Log2InitSize = 6); 125 FoldingSetBase(FoldingSetBase &&Arg); 126 FoldingSetBase &operator=(FoldingSetBase &&RHS); 127 ~FoldingSetBase(); 128 129 public: 130 //===--------------------------------------------------------------------===// 131 /// Node - This class is used to maintain the singly linked bucket list in 132 /// a folding set. 133 class Node { 134 private: 135 // NextInFoldingSetBucket - next link in the bucket list. 136 void *NextInFoldingSetBucket = nullptr; 137 138 public: 139 Node() = default; 140 141 // Accessors 142 void *getNextInBucket() const { return NextInFoldingSetBucket; } 143 void SetNextInBucket(void *N) { NextInFoldingSetBucket = N; } 144 }; 145 146 /// clear - Remove all nodes from the folding set. 147 void clear(); 148 149 /// size - Returns the number of nodes in the folding set. 150 unsigned size() const { return NumNodes; } 151 152 /// empty - Returns true if there are no nodes in the folding set. 153 bool empty() const { return NumNodes == 0; } 154 155 /// capacity - Returns the number of nodes permitted in the folding set 156 /// before a rebucket operation is performed. 157 unsigned capacity() { 158 // We allow a load factor of up to 2.0, 159 // so that means our capacity is NumBuckets * 2 160 return NumBuckets * 2; 161 } 162 163 protected: 164 /// Functions provided by the derived class to compute folding properties. 165 /// This is effectively a vtable for FoldingSetBase, except that we don't 166 /// actually store a pointer to it in the object. 167 struct FoldingSetInfo { 168 /// GetNodeProfile - Instantiations of the FoldingSet template implement 169 /// this function to gather data bits for the given node. 170 void (*GetNodeProfile)(const FoldingSetBase *Self, Node *N, 171 FoldingSetNodeID &ID); 172 173 /// NodeEquals - Instantiations of the FoldingSet template implement 174 /// this function to compare the given node with the given ID. 175 bool (*NodeEquals)(const FoldingSetBase *Self, Node *N, 176 const FoldingSetNodeID &ID, unsigned IDHash, 177 FoldingSetNodeID &TempID); 178 179 /// ComputeNodeHash - Instantiations of the FoldingSet template implement 180 /// this function to compute a hash value for the given node. 181 unsigned (*ComputeNodeHash)(const FoldingSetBase *Self, Node *N, 182 FoldingSetNodeID &TempID); 183 }; 184 185 private: 186 /// GrowHashTable - Double the size of the hash table and rehash everything. 187 void GrowHashTable(const FoldingSetInfo &Info); 188 189 /// GrowBucketCount - resize the hash table and rehash everything. 190 /// NewBucketCount must be a power of two, and must be greater than the old 191 /// bucket count. 192 void GrowBucketCount(unsigned NewBucketCount, const FoldingSetInfo &Info); 193 194 protected: 195 // The below methods are protected to encourage subclasses to provide a more 196 // type-safe API. 197 198 /// reserve - Increase the number of buckets such that adding the 199 /// EltCount-th node won't cause a rebucket operation. reserve is permitted 200 /// to allocate more space than requested by EltCount. 201 void reserve(unsigned EltCount, const FoldingSetInfo &Info); 202 203 /// RemoveNode - Remove a node from the folding set, returning true if one 204 /// was removed or false if the node was not in the folding set. 205 bool RemoveNode(Node *N); 206 207 /// GetOrInsertNode - If there is an existing simple Node exactly 208 /// equal to the specified node, return it. Otherwise, insert 'N' and return 209 /// it instead. 210 Node *GetOrInsertNode(Node *N, const FoldingSetInfo &Info); 211 212 /// FindNodeOrInsertPos - Look up the node specified by ID. If it exists, 213 /// return it. If not, return the insertion token that will make insertion 214 /// faster. 215 Node *FindNodeOrInsertPos(const FoldingSetNodeID &ID, void *&InsertPos, 216 const FoldingSetInfo &Info); 217 218 /// InsertNode - Insert the specified node into the folding set, knowing that 219 /// it is not already in the folding set. InsertPos must be obtained from 220 /// FindNodeOrInsertPos. 221 void InsertNode(Node *N, void *InsertPos, const FoldingSetInfo &Info); 222 }; 223 224 //===----------------------------------------------------------------------===// 225 226 /// DefaultFoldingSetTrait - This class provides default implementations 227 /// for FoldingSetTrait implementations. 228 template<typename T> struct DefaultFoldingSetTrait { 229 static void Profile(const T &X, FoldingSetNodeID &ID) { 230 X.Profile(ID); 231 } 232 static void Profile(T &X, FoldingSetNodeID &ID) { 233 X.Profile(ID); 234 } 235 236 // Equals - Test if the profile for X would match ID, using TempID 237 // to compute a temporary ID if necessary. The default implementation 238 // just calls Profile and does a regular comparison. Implementations 239 // can override this to provide more efficient implementations. 240 static inline bool Equals(T &X, const FoldingSetNodeID &ID, unsigned IDHash, 241 FoldingSetNodeID &TempID); 242 243 // ComputeHash - Compute a hash value for X, using TempID to 244 // compute a temporary ID if necessary. The default implementation 245 // just calls Profile and does a regular hash computation. 246 // Implementations can override this to provide more efficient 247 // implementations. 248 static inline unsigned ComputeHash(T &X, FoldingSetNodeID &TempID); 249 }; 250 251 /// FoldingSetTrait - This trait class is used to define behavior of how 252 /// to "profile" (in the FoldingSet parlance) an object of a given type. 253 /// The default behavior is to invoke a 'Profile' method on an object, but 254 /// through template specialization the behavior can be tailored for specific 255 /// types. Combined with the FoldingSetNodeWrapper class, one can add objects 256 /// to FoldingSets that were not originally designed to have that behavior. 257 template<typename T> struct FoldingSetTrait 258 : public DefaultFoldingSetTrait<T> {}; 259 260 /// DefaultContextualFoldingSetTrait - Like DefaultFoldingSetTrait, but 261 /// for ContextualFoldingSets. 262 template<typename T, typename Ctx> 263 struct DefaultContextualFoldingSetTrait { 264 static void Profile(T &X, FoldingSetNodeID &ID, Ctx Context) { 265 X.Profile(ID, Context); 266 } 267 268 static inline bool Equals(T &X, const FoldingSetNodeID &ID, unsigned IDHash, 269 FoldingSetNodeID &TempID, Ctx Context); 270 static inline unsigned ComputeHash(T &X, FoldingSetNodeID &TempID, 271 Ctx Context); 272 }; 273 274 /// ContextualFoldingSetTrait - Like FoldingSetTrait, but for 275 /// ContextualFoldingSets. 276 template<typename T, typename Ctx> struct ContextualFoldingSetTrait 277 : public DefaultContextualFoldingSetTrait<T, Ctx> {}; 278 279 //===--------------------------------------------------------------------===// 280 /// FoldingSetNodeIDRef - This class describes a reference to an interned 281 /// FoldingSetNodeID, which can be a useful to store node id data rather 282 /// than using plain FoldingSetNodeIDs, since the 32-element SmallVector 283 /// is often much larger than necessary, and the possibility of heap 284 /// allocation means it requires a non-trivial destructor call. 285 class FoldingSetNodeIDRef { 286 const unsigned *Data = nullptr; 287 size_t Size = 0; 288 289 public: 290 FoldingSetNodeIDRef() = default; 291 FoldingSetNodeIDRef(const unsigned *D, size_t S) : Data(D), Size(S) {} 292 293 /// ComputeHash - Compute a strong hash value for this FoldingSetNodeIDRef, 294 /// used to lookup the node in the FoldingSetBase. 295 unsigned ComputeHash() const; 296 297 bool operator==(FoldingSetNodeIDRef) const; 298 299 bool operator!=(FoldingSetNodeIDRef RHS) const { return !(*this == RHS); } 300 301 /// Used to compare the "ordering" of two nodes as defined by the 302 /// profiled bits and their ordering defined by memcmp(). 303 bool operator<(FoldingSetNodeIDRef) const; 304 305 const unsigned *getData() const { return Data; } 306 size_t getSize() const { return Size; } 307 }; 308 309 //===--------------------------------------------------------------------===// 310 /// FoldingSetNodeID - This class is used to gather all the unique data bits of 311 /// a node. When all the bits are gathered this class is used to produce a 312 /// hash value for the node. 313 class FoldingSetNodeID { 314 /// Bits - Vector of all the data bits that make the node unique. 315 /// Use a SmallVector to avoid a heap allocation in the common case. 316 SmallVector<unsigned, 32> Bits; 317 318 public: 319 FoldingSetNodeID() = default; 320 321 FoldingSetNodeID(FoldingSetNodeIDRef Ref) 322 : Bits(Ref.getData(), Ref.getData() + Ref.getSize()) {} 323 324 /// Add* - Add various data types to Bit data. 325 void AddPointer(const void *Ptr); 326 void AddInteger(signed I); 327 void AddInteger(unsigned I); 328 void AddInteger(long I); 329 void AddInteger(unsigned long I); 330 void AddInteger(long long I); 331 void AddInteger(unsigned long long I); 332 void AddBoolean(bool B) { AddInteger(B ? 1U : 0U); } 333 void AddString(StringRef String); 334 void AddNodeID(const FoldingSetNodeID &ID); 335 336 template <typename T> 337 inline void Add(const T &x) { FoldingSetTrait<T>::Profile(x, *this); } 338 339 /// clear - Clear the accumulated profile, allowing this FoldingSetNodeID 340 /// object to be used to compute a new profile. 341 inline void clear() { Bits.clear(); } 342 343 /// ComputeHash - Compute a strong hash value for this FoldingSetNodeID, used 344 /// to lookup the node in the FoldingSetBase. 345 unsigned ComputeHash() const; 346 347 /// operator== - Used to compare two nodes to each other. 348 bool operator==(const FoldingSetNodeID &RHS) const; 349 bool operator==(const FoldingSetNodeIDRef RHS) const; 350 351 bool operator!=(const FoldingSetNodeID &RHS) const { return !(*this == RHS); } 352 bool operator!=(const FoldingSetNodeIDRef RHS) const { return !(*this ==RHS);} 353 354 /// Used to compare the "ordering" of two nodes as defined by the 355 /// profiled bits and their ordering defined by memcmp(). 356 bool operator<(const FoldingSetNodeID &RHS) const; 357 bool operator<(const FoldingSetNodeIDRef RHS) const; 358 359 /// Intern - Copy this node's data to a memory region allocated from the 360 /// given allocator and return a FoldingSetNodeIDRef describing the 361 /// interned data. 362 FoldingSetNodeIDRef Intern(BumpPtrAllocator &Allocator) const; 363 }; 364 365 // Convenience type to hide the implementation of the folding set. 366 using FoldingSetNode = FoldingSetBase::Node; 367 template<class T> class FoldingSetIterator; 368 template<class T> class FoldingSetBucketIterator; 369 370 // Definitions of FoldingSetTrait and ContextualFoldingSetTrait functions, which 371 // require the definition of FoldingSetNodeID. 372 template<typename T> 373 inline bool 374 DefaultFoldingSetTrait<T>::Equals(T &X, const FoldingSetNodeID &ID, 375 unsigned /*IDHash*/, 376 FoldingSetNodeID &TempID) { 377 FoldingSetTrait<T>::Profile(X, TempID); 378 return TempID == ID; 379 } 380 template<typename T> 381 inline unsigned 382 DefaultFoldingSetTrait<T>::ComputeHash(T &X, FoldingSetNodeID &TempID) { 383 FoldingSetTrait<T>::Profile(X, TempID); 384 return TempID.ComputeHash(); 385 } 386 template<typename T, typename Ctx> 387 inline bool 388 DefaultContextualFoldingSetTrait<T, Ctx>::Equals(T &X, 389 const FoldingSetNodeID &ID, 390 unsigned /*IDHash*/, 391 FoldingSetNodeID &TempID, 392 Ctx Context) { 393 ContextualFoldingSetTrait<T, Ctx>::Profile(X, TempID, Context); 394 return TempID == ID; 395 } 396 template<typename T, typename Ctx> 397 inline unsigned 398 DefaultContextualFoldingSetTrait<T, Ctx>::ComputeHash(T &X, 399 FoldingSetNodeID &TempID, 400 Ctx Context) { 401 ContextualFoldingSetTrait<T, Ctx>::Profile(X, TempID, Context); 402 return TempID.ComputeHash(); 403 } 404 405 //===----------------------------------------------------------------------===// 406 /// FoldingSetImpl - An implementation detail that lets us share code between 407 /// FoldingSet and ContextualFoldingSet. 408 template <class Derived, class T> class FoldingSetImpl : public FoldingSetBase { 409 protected: 410 explicit FoldingSetImpl(unsigned Log2InitSize) 411 : FoldingSetBase(Log2InitSize) {} 412 413 FoldingSetImpl(FoldingSetImpl &&Arg) = default; 414 FoldingSetImpl &operator=(FoldingSetImpl &&RHS) = default; 415 ~FoldingSetImpl() = default; 416 417 public: 418 using iterator = FoldingSetIterator<T>; 419 420 iterator begin() { return iterator(Buckets); } 421 iterator end() { return iterator(Buckets+NumBuckets); } 422 423 using const_iterator = FoldingSetIterator<const T>; 424 425 const_iterator begin() const { return const_iterator(Buckets); } 426 const_iterator end() const { return const_iterator(Buckets+NumBuckets); } 427 428 using bucket_iterator = FoldingSetBucketIterator<T>; 429 430 bucket_iterator bucket_begin(unsigned hash) { 431 return bucket_iterator(Buckets + (hash & (NumBuckets-1))); 432 } 433 434 bucket_iterator bucket_end(unsigned hash) { 435 return bucket_iterator(Buckets + (hash & (NumBuckets-1)), true); 436 } 437 438 /// reserve - Increase the number of buckets such that adding the 439 /// EltCount-th node won't cause a rebucket operation. reserve is permitted 440 /// to allocate more space than requested by EltCount. 441 void reserve(unsigned EltCount) { 442 return FoldingSetBase::reserve(EltCount, Derived::getFoldingSetInfo()); 443 } 444 445 /// RemoveNode - Remove a node from the folding set, returning true if one 446 /// was removed or false if the node was not in the folding set. 447 bool RemoveNode(T *N) { 448 return FoldingSetBase::RemoveNode(N); 449 } 450 451 /// GetOrInsertNode - If there is an existing simple Node exactly 452 /// equal to the specified node, return it. Otherwise, insert 'N' and 453 /// return it instead. 454 T *GetOrInsertNode(T *N) { 455 return static_cast<T *>( 456 FoldingSetBase::GetOrInsertNode(N, Derived::getFoldingSetInfo())); 457 } 458 459 /// FindNodeOrInsertPos - Look up the node specified by ID. If it exists, 460 /// return it. If not, return the insertion token that will make insertion 461 /// faster. 462 T *FindNodeOrInsertPos(const FoldingSetNodeID &ID, void *&InsertPos) { 463 return static_cast<T *>(FoldingSetBase::FindNodeOrInsertPos( 464 ID, InsertPos, Derived::getFoldingSetInfo())); 465 } 466 467 /// InsertNode - Insert the specified node into the folding set, knowing that 468 /// it is not already in the folding set. InsertPos must be obtained from 469 /// FindNodeOrInsertPos. 470 void InsertNode(T *N, void *InsertPos) { 471 FoldingSetBase::InsertNode(N, InsertPos, Derived::getFoldingSetInfo()); 472 } 473 474 /// InsertNode - Insert the specified node into the folding set, knowing that 475 /// it is not already in the folding set. 476 void InsertNode(T *N) { 477 T *Inserted = GetOrInsertNode(N); 478 (void)Inserted; 479 assert(Inserted == N && "Node already inserted!"); 480 } 481 }; 482 483 //===----------------------------------------------------------------------===// 484 /// FoldingSet - This template class is used to instantiate a specialized 485 /// implementation of the folding set to the node class T. T must be a 486 /// subclass of FoldingSetNode and implement a Profile function. 487 /// 488 /// Note that this set type is movable and move-assignable. However, its 489 /// moved-from state is not a valid state for anything other than 490 /// move-assigning and destroying. This is primarily to enable movable APIs 491 /// that incorporate these objects. 492 template <class T> 493 class FoldingSet : public FoldingSetImpl<FoldingSet<T>, T> { 494 using Super = FoldingSetImpl<FoldingSet, T>; 495 using Node = typename Super::Node; 496 497 /// GetNodeProfile - Each instantiation of the FoldingSet needs to provide a 498 /// way to convert nodes into a unique specifier. 499 static void GetNodeProfile(const FoldingSetBase *, Node *N, 500 FoldingSetNodeID &ID) { 501 T *TN = static_cast<T *>(N); 502 FoldingSetTrait<T>::Profile(*TN, ID); 503 } 504 505 /// NodeEquals - Instantiations may optionally provide a way to compare a 506 /// node with a specified ID. 507 static bool NodeEquals(const FoldingSetBase *, Node *N, 508 const FoldingSetNodeID &ID, unsigned IDHash, 509 FoldingSetNodeID &TempID) { 510 T *TN = static_cast<T *>(N); 511 return FoldingSetTrait<T>::Equals(*TN, ID, IDHash, TempID); 512 } 513 514 /// ComputeNodeHash - Instantiations may optionally provide a way to compute a 515 /// hash value directly from a node. 516 static unsigned ComputeNodeHash(const FoldingSetBase *, Node *N, 517 FoldingSetNodeID &TempID) { 518 T *TN = static_cast<T *>(N); 519 return FoldingSetTrait<T>::ComputeHash(*TN, TempID); 520 } 521 522 static const FoldingSetBase::FoldingSetInfo &getFoldingSetInfo() { 523 static constexpr FoldingSetBase::FoldingSetInfo Info = { 524 GetNodeProfile, NodeEquals, ComputeNodeHash}; 525 return Info; 526 } 527 friend Super; 528 529 public: 530 explicit FoldingSet(unsigned Log2InitSize = 6) : Super(Log2InitSize) {} 531 FoldingSet(FoldingSet &&Arg) = default; 532 FoldingSet &operator=(FoldingSet &&RHS) = default; 533 }; 534 535 //===----------------------------------------------------------------------===// 536 /// ContextualFoldingSet - This template class is a further refinement 537 /// of FoldingSet which provides a context argument when calling 538 /// Profile on its nodes. Currently, that argument is fixed at 539 /// initialization time. 540 /// 541 /// T must be a subclass of FoldingSetNode and implement a Profile 542 /// function with signature 543 /// void Profile(FoldingSetNodeID &, Ctx); 544 template <class T, class Ctx> 545 class ContextualFoldingSet 546 : public FoldingSetImpl<ContextualFoldingSet<T, Ctx>, T> { 547 // Unfortunately, this can't derive from FoldingSet<T> because the 548 // construction of the vtable for FoldingSet<T> requires 549 // FoldingSet<T>::GetNodeProfile to be instantiated, which in turn 550 // requires a single-argument T::Profile(). 551 552 using Super = FoldingSetImpl<ContextualFoldingSet, T>; 553 using Node = typename Super::Node; 554 555 Ctx Context; 556 557 static const Ctx &getContext(const FoldingSetBase *Base) { 558 return static_cast<const ContextualFoldingSet*>(Base)->Context; 559 } 560 561 /// GetNodeProfile - Each instantiatation of the FoldingSet needs to provide a 562 /// way to convert nodes into a unique specifier. 563 static void GetNodeProfile(const FoldingSetBase *Base, Node *N, 564 FoldingSetNodeID &ID) { 565 T *TN = static_cast<T *>(N); 566 ContextualFoldingSetTrait<T, Ctx>::Profile(*TN, ID, getContext(Base)); 567 } 568 569 static bool NodeEquals(const FoldingSetBase *Base, Node *N, 570 const FoldingSetNodeID &ID, unsigned IDHash, 571 FoldingSetNodeID &TempID) { 572 T *TN = static_cast<T *>(N); 573 return ContextualFoldingSetTrait<T, Ctx>::Equals(*TN, ID, IDHash, TempID, 574 getContext(Base)); 575 } 576 577 static unsigned ComputeNodeHash(const FoldingSetBase *Base, Node *N, 578 FoldingSetNodeID &TempID) { 579 T *TN = static_cast<T *>(N); 580 return ContextualFoldingSetTrait<T, Ctx>::ComputeHash(*TN, TempID, 581 getContext(Base)); 582 } 583 584 static const FoldingSetBase::FoldingSetInfo &getFoldingSetInfo() { 585 static constexpr FoldingSetBase::FoldingSetInfo Info = { 586 GetNodeProfile, NodeEquals, ComputeNodeHash}; 587 return Info; 588 } 589 friend Super; 590 591 public: 592 explicit ContextualFoldingSet(Ctx Context, unsigned Log2InitSize = 6) 593 : Super(Log2InitSize), Context(Context) {} 594 595 Ctx getContext() const { return Context; } 596 }; 597 598 //===----------------------------------------------------------------------===// 599 /// FoldingSetVector - This template class combines a FoldingSet and a vector 600 /// to provide the interface of FoldingSet but with deterministic iteration 601 /// order based on the insertion order. T must be a subclass of FoldingSetNode 602 /// and implement a Profile function. 603 template <class T, class VectorT = SmallVector<T*, 8>> 604 class FoldingSetVector { 605 FoldingSet<T> Set; 606 VectorT Vector; 607 608 public: 609 explicit FoldingSetVector(unsigned Log2InitSize = 6) : Set(Log2InitSize) {} 610 611 using iterator = pointee_iterator<typename VectorT::iterator>; 612 613 iterator begin() { return Vector.begin(); } 614 iterator end() { return Vector.end(); } 615 616 using const_iterator = pointee_iterator<typename VectorT::const_iterator>; 617 618 const_iterator begin() const { return Vector.begin(); } 619 const_iterator end() const { return Vector.end(); } 620 621 /// clear - Remove all nodes from the folding set. 622 void clear() { Set.clear(); Vector.clear(); } 623 624 /// FindNodeOrInsertPos - Look up the node specified by ID. If it exists, 625 /// return it. If not, return the insertion token that will make insertion 626 /// faster. 627 T *FindNodeOrInsertPos(const FoldingSetNodeID &ID, void *&InsertPos) { 628 return Set.FindNodeOrInsertPos(ID, InsertPos); 629 } 630 631 /// GetOrInsertNode - If there is an existing simple Node exactly 632 /// equal to the specified node, return it. Otherwise, insert 'N' and 633 /// return it instead. 634 T *GetOrInsertNode(T *N) { 635 T *Result = Set.GetOrInsertNode(N); 636 if (Result == N) Vector.push_back(N); 637 return Result; 638 } 639 640 /// InsertNode - Insert the specified node into the folding set, knowing that 641 /// it is not already in the folding set. InsertPos must be obtained from 642 /// FindNodeOrInsertPos. 643 void InsertNode(T *N, void *InsertPos) { 644 Set.InsertNode(N, InsertPos); 645 Vector.push_back(N); 646 } 647 648 /// InsertNode - Insert the specified node into the folding set, knowing that 649 /// it is not already in the folding set. 650 void InsertNode(T *N) { 651 Set.InsertNode(N); 652 Vector.push_back(N); 653 } 654 655 /// size - Returns the number of nodes in the folding set. 656 unsigned size() const { return Set.size(); } 657 658 /// empty - Returns true if there are no nodes in the folding set. 659 bool empty() const { return Set.empty(); } 660 }; 661 662 //===----------------------------------------------------------------------===// 663 /// FoldingSetIteratorImpl - This is the common iterator support shared by all 664 /// folding sets, which knows how to walk the folding set hash table. 665 class FoldingSetIteratorImpl { 666 protected: 667 FoldingSetNode *NodePtr; 668 669 FoldingSetIteratorImpl(void **Bucket); 670 671 void advance(); 672 673 public: 674 bool operator==(const FoldingSetIteratorImpl &RHS) const { 675 return NodePtr == RHS.NodePtr; 676 } 677 bool operator!=(const FoldingSetIteratorImpl &RHS) const { 678 return NodePtr != RHS.NodePtr; 679 } 680 }; 681 682 template <class T> class FoldingSetIterator : public FoldingSetIteratorImpl { 683 public: 684 explicit FoldingSetIterator(void **Bucket) : FoldingSetIteratorImpl(Bucket) {} 685 686 T &operator*() const { 687 return *static_cast<T*>(NodePtr); 688 } 689 690 T *operator->() const { 691 return static_cast<T*>(NodePtr); 692 } 693 694 inline FoldingSetIterator &operator++() { // Preincrement 695 advance(); 696 return *this; 697 } 698 FoldingSetIterator operator++(int) { // Postincrement 699 FoldingSetIterator tmp = *this; ++*this; return tmp; 700 } 701 }; 702 703 //===----------------------------------------------------------------------===// 704 /// FoldingSetBucketIteratorImpl - This is the common bucket iterator support 705 /// shared by all folding sets, which knows how to walk a particular bucket 706 /// of a folding set hash table. 707 class FoldingSetBucketIteratorImpl { 708 protected: 709 void *Ptr; 710 711 explicit FoldingSetBucketIteratorImpl(void **Bucket); 712 713 FoldingSetBucketIteratorImpl(void **Bucket, bool) : Ptr(Bucket) {} 714 715 void advance() { 716 void *Probe = static_cast<FoldingSetNode*>(Ptr)->getNextInBucket(); 717 uintptr_t x = reinterpret_cast<uintptr_t>(Probe) & ~0x1; 718 Ptr = reinterpret_cast<void*>(x); 719 } 720 721 public: 722 bool operator==(const FoldingSetBucketIteratorImpl &RHS) const { 723 return Ptr == RHS.Ptr; 724 } 725 bool operator!=(const FoldingSetBucketIteratorImpl &RHS) const { 726 return Ptr != RHS.Ptr; 727 } 728 }; 729 730 template <class T> 731 class FoldingSetBucketIterator : public FoldingSetBucketIteratorImpl { 732 public: 733 explicit FoldingSetBucketIterator(void **Bucket) : 734 FoldingSetBucketIteratorImpl(Bucket) {} 735 736 FoldingSetBucketIterator(void **Bucket, bool) : 737 FoldingSetBucketIteratorImpl(Bucket, true) {} 738 739 T &operator*() const { return *static_cast<T*>(Ptr); } 740 T *operator->() const { return static_cast<T*>(Ptr); } 741 742 inline FoldingSetBucketIterator &operator++() { // Preincrement 743 advance(); 744 return *this; 745 } 746 FoldingSetBucketIterator operator++(int) { // Postincrement 747 FoldingSetBucketIterator tmp = *this; ++*this; return tmp; 748 } 749 }; 750 751 //===----------------------------------------------------------------------===// 752 /// FoldingSetNodeWrapper - This template class is used to "wrap" arbitrary 753 /// types in an enclosing object so that they can be inserted into FoldingSets. 754 template <typename T> 755 class FoldingSetNodeWrapper : public FoldingSetNode { 756 T data; 757 758 public: 759 template <typename... Ts> 760 explicit FoldingSetNodeWrapper(Ts &&... Args) 761 : data(std::forward<Ts>(Args)...) {} 762 763 void Profile(FoldingSetNodeID &ID) { FoldingSetTrait<T>::Profile(data, ID); } 764 765 T &getValue() { return data; } 766 const T &getValue() const { return data; } 767 768 operator T&() { return data; } 769 operator const T&() const { return data; } 770 }; 771 772 //===----------------------------------------------------------------------===// 773 /// FastFoldingSetNode - This is a subclass of FoldingSetNode which stores 774 /// a FoldingSetNodeID value rather than requiring the node to recompute it 775 /// each time it is needed. This trades space for speed (which can be 776 /// significant if the ID is long), and it also permits nodes to drop 777 /// information that would otherwise only be required for recomputing an ID. 778 class FastFoldingSetNode : public FoldingSetNode { 779 FoldingSetNodeID FastID; 780 781 protected: 782 explicit FastFoldingSetNode(const FoldingSetNodeID &ID) : FastID(ID) {} 783 784 public: 785 void Profile(FoldingSetNodeID &ID) const { ID.AddNodeID(FastID); } 786 }; 787 788 //===----------------------------------------------------------------------===// 789 // Partial specializations of FoldingSetTrait. 790 791 template<typename T> struct FoldingSetTrait<T*> { 792 static inline void Profile(T *X, FoldingSetNodeID &ID) { 793 ID.AddPointer(X); 794 } 795 }; 796 template <typename T1, typename T2> 797 struct FoldingSetTrait<std::pair<T1, T2>> { 798 static inline void Profile(const std::pair<T1, T2> &P, 799 FoldingSetNodeID &ID) { 800 ID.Add(P.first); 801 ID.Add(P.second); 802 } 803 }; 804 805 } // end namespace llvm 806 807 #endif // LLVM_ADT_FOLDINGSET_H 808