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