FoldingSet.h revision e1bf7fdcb4be19c556f4c789dd43864f5d13c5e4
13447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein//===-- llvm/ADT/FoldingSet.h - Uniquing Hash Set ---------------*- C++ -*-===// 23447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein// 3324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// The LLVM Compiler Infrastructure 43447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein// 53447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein// This file is distributed under the University of Illinois Open Source 63447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein// License. See LICENSE.TXT for details. 73447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein// 83447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein//===----------------------------------------------------------------------===// 93447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein// 10324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// This file defines a hash set that can be used to remove duplication of nodes 113447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein// in a graph. This code was originally created by Chris Lattner for use with 12324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// SelectionDAGCSEMap, but was isolated to provide use across the llvm code set. 13324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver// 143447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein//===----------------------------------------------------------------------===// 15324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver 163447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein#ifndef LLVM_ADT_FOLDINGSET_H 173447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein#define LLVM_ADT_FOLDINGSET_H 183447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein 193447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein#include "llvm/Support/DataTypes.h" 203447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein#include "llvm/ADT/SmallVector.h" 213447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein#include <string> 223447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein 233447a5916aa62f44de24cc441fc9987116ddff52Andrew Sappersteinnamespace llvm { 243447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein class APFloat; 253447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein class APInt; 263447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein 27324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver/// This folding set used for two purposes: 28324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver/// 1. Given information about a node we want to create, look up the unique 293447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein/// instance of the node in the set. If the node already exists, return 30324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver/// it, otherwise return the bucket it should be inserted into. 31324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver/// 2. Given a node that has already been created, remove it from the set. 32324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver/// 33324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver/// This class is implemented as a single-link chained hash table, where the 34324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver/// "buckets" are actually the nodes themselves (the next pointer is in the 35324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver/// node). The last node points back to the bucket to simplify node removal. 36324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver/// 37324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver/// Any node that is to be included in the folding set must be a subclass of 38324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver/// FoldingSetNode. The node class must also define a Profile method used to 39324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver/// establish the unique bits of data for the node. The Profile method is 403447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein/// passed a FoldingSetNodeID object which is used to gather the bits. Just 41324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver/// call one of the Add* functions defined in the FoldingSetImpl::NodeID class. 42324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver/// NOTE: That the folding set does not own the nodes and it is the 43324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver/// responsibility of the user to dispose of the nodes. 44324c4644fee44b9898524c09511bd33c3f12e2dfBen Gruver/// 453447a5916aa62f44de24cc441fc9987116ddff52Andrew Sapperstein/// Eg. 46/// class MyNode : public FoldingSetNode { 47/// private: 48/// std::string Name; 49/// unsigned Value; 50/// public: 51/// MyNode(const char *N, unsigned V) : Name(N), Value(V) {} 52/// ... 53/// void Profile(FoldingSetNodeID &ID) { 54/// ID.AddString(Name); 55/// ID.AddInteger(Value); 56/// } 57/// ... 58/// }; 59/// 60/// To define the folding set itself use the FoldingSet template; 61/// 62/// Eg. 63/// FoldingSet<MyNode> MyFoldingSet; 64/// 65/// Four public methods are available to manipulate the folding set; 66/// 67/// 1) If you have an existing node that you want add to the set but unsure 68/// that the node might already exist then call; 69/// 70/// MyNode *M = MyFoldingSet.GetOrInsertNode(N); 71/// 72/// If The result is equal to the input then the node has been inserted. 73/// Otherwise, the result is the node existing in the folding set, and the 74/// input can be discarded (use the result instead.) 75/// 76/// 2) If you are ready to construct a node but want to check if it already 77/// exists, then call FindNodeOrInsertPos with a FoldingSetNodeID of the bits to 78/// check; 79/// 80/// FoldingSetNodeID ID; 81/// ID.AddString(Name); 82/// ID.AddInteger(Value); 83/// void *InsertPoint; 84/// 85/// MyNode *M = MyFoldingSet.FindNodeOrInsertPos(ID, InsertPoint); 86/// 87/// If found then M with be non-NULL, else InsertPoint will point to where it 88/// should be inserted using InsertNode. 89/// 90/// 3) If you get a NULL result from FindNodeOrInsertPos then you can as a new 91/// node with FindNodeOrInsertPos; 92/// 93/// InsertNode(N, InsertPoint); 94/// 95/// 4) Finally, if you want to remove a node from the folding set call; 96/// 97/// bool WasRemoved = RemoveNode(N); 98/// 99/// The result indicates whether the node existed in the folding set. 100 101class FoldingSetNodeID; 102 103//===----------------------------------------------------------------------===// 104/// FoldingSetImpl - Implements the folding set functionality. The main 105/// structure is an array of buckets. Each bucket is indexed by the hash of 106/// the nodes it contains. The bucket itself points to the nodes contained 107/// in the bucket via a singly linked list. The last node in the list points 108/// back to the bucket to facilitate node removal. 109/// 110class FoldingSetImpl { 111protected: 112 /// Buckets - Array of bucket chains. 113 /// 114 void **Buckets; 115 116 /// NumBuckets - Length of the Buckets array. Always a power of 2. 117 /// 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 124public: 125 explicit FoldingSetImpl(unsigned Log2InitSize = 6); 126 virtual ~FoldingSetImpl(); 127 128 //===--------------------------------------------------------------------===// 129 /// Node - This class is used to maintain the singly linked bucket list in 130 /// a folding set. 131 /// 132 class Node { 133 private: 134 // NextInFoldingSetBucket - next link in the bucket list. 135 void *NextInFoldingSetBucket; 136 137 public: 138 139 Node() : NextInFoldingSetBucket(0) {} 140 141 // Accessors 142 void *getNextInBucket() const { return NextInFoldingSetBucket; } 143 void SetNextInBucket(void *N) { NextInFoldingSetBucket = N; } 144 }; 145 146 /// RemoveNode - Remove a node from the folding set, returning true if one 147 /// was removed or false if the node was not in the folding set. 148 bool RemoveNode(Node *N); 149 150 /// GetOrInsertNode - If there is an existing simple Node exactly 151 /// equal to the specified node, return it. Otherwise, insert 'N' and return 152 /// it instead. 153 Node *GetOrInsertNode(Node *N); 154 155 /// FindNodeOrInsertPos - Look up the node specified by ID. If it exists, 156 /// return it. If not, return the insertion token that will make insertion 157 /// faster. 158 Node *FindNodeOrInsertPos(const FoldingSetNodeID &ID, void *&InsertPos); 159 160 /// InsertNode - Insert the specified node into the folding set, knowing that 161 /// it is not already in the folding set. InsertPos must be obtained from 162 /// FindNodeOrInsertPos. 163 void InsertNode(Node *N, void *InsertPos); 164 165 /// size - Returns the number of nodes in the folding set. 166 unsigned size() const { return NumNodes; } 167 168private: 169 170 /// GrowHashTable - Double the size of the hash table and rehash everything. 171 /// 172 void GrowHashTable(); 173 174protected: 175 176 /// GetNodeProfile - Instantiations of the FoldingSet template implement 177 /// this function to gather data bits for the given node. 178 virtual void GetNodeProfile(FoldingSetNodeID &ID, Node *N) const = 0; 179}; 180 181//===----------------------------------------------------------------------===// 182/// FoldingSetTrait - This trait class is used to define behavior of how 183/// to "profile" (in the FoldingSet parlance) an object of a given type. 184/// The default behavior is to invoke a 'Profile' method on an object, but 185/// through template specialization the behavior can be tailored for specific 186/// types. Combined with the FoldingSetNodeWrapper classs, one can add objects 187/// to FoldingSets that were not originally designed to have that behavior. 188/// 189template<typename T> struct FoldingSetTrait { 190 static inline void Profile(const T& X, FoldingSetNodeID& ID) { X.Profile(ID);} 191 static inline void Profile(T& X, FoldingSetNodeID& ID) { X.Profile(ID); } 192}; 193 194//===--------------------------------------------------------------------===// 195/// FoldingSetNodeID - This class is used to gather all the unique data bits of 196/// a node. When all the bits are gathered this class is used to produce a 197/// hash value for the node. 198/// 199class FoldingSetNodeID { 200 /// Bits - Vector of all the data bits that make the node unique. 201 /// Use a SmallVector to avoid a heap allocation in the common case. 202 SmallVector<unsigned, 32> Bits; 203 204public: 205 FoldingSetNodeID() {} 206 207 /// getRawData - Return the ith entry in the Bits data. 208 /// 209 unsigned getRawData(unsigned i) const { 210 return Bits[i]; 211 } 212 213 /// Add* - Add various data types to Bit data. 214 /// 215 void AddPointer(const void *Ptr); 216 void AddInteger(signed I); 217 void AddInteger(unsigned I); 218 void AddInteger(int64_t I); 219 void AddInteger(uint64_t I); 220 void AddFloat(float F); 221 void AddDouble(double D); 222 void AddString(const std::string &String); 223 224 template <typename T> 225 inline void Add(const T& x) { FoldingSetTrait<T>::Profile(x, *this); } 226 227 /// clear - Clear the accumulated profile, allowing this FoldingSetNodeID 228 /// object to be used to compute a new profile. 229 inline void clear() { Bits.clear(); } 230 231 /// ComputeHash - Compute a strong hash value for this FoldingSetNodeID, used 232 /// to lookup the node in the FoldingSetImpl. 233 unsigned ComputeHash() const; 234 235 /// operator== - Used to compare two nodes to each other. 236 /// 237 bool operator==(const FoldingSetNodeID &RHS) const; 238}; 239 240// Convenience type to hide the implementation of the folding set. 241typedef FoldingSetImpl::Node FoldingSetNode; 242template<class T> class FoldingSetIterator; 243template<class T> class FoldingSetBucketIterator; 244 245//===----------------------------------------------------------------------===// 246/// FoldingSet - This template class is used to instantiate a specialized 247/// implementation of the folding set to the node class T. T must be a 248/// subclass of FoldingSetNode and implement a Profile function. 249/// 250template<class T> class FoldingSet : public FoldingSetImpl { 251private: 252 /// GetNodeProfile - Each instantiatation of the FoldingSet needs to provide a 253 /// way to convert nodes into a unique specifier. 254 virtual void GetNodeProfile(FoldingSetNodeID &ID, Node *N) const { 255 T *TN = static_cast<T *>(N); 256 FoldingSetTrait<T>::Profile(*TN,ID); 257 } 258 259public: 260 explicit FoldingSet(unsigned Log2InitSize = 6) 261 : FoldingSetImpl(Log2InitSize) 262 {} 263 264 typedef FoldingSetIterator<T> iterator; 265 iterator begin() { return iterator(Buckets); } 266 iterator end() { return iterator(Buckets+NumBuckets); } 267 268 typedef FoldingSetIterator<const T> const_iterator; 269 const_iterator begin() const { return const_iterator(Buckets); } 270 const_iterator end() const { return const_iterator(Buckets+NumBuckets); } 271 272 typedef FoldingSetBucketIterator<T> bucket_iterator; 273 274 bucket_iterator bucket_begin(unsigned hash) { 275 return bucket_iterator(Buckets + (hash & (NumBuckets-1))); 276 } 277 278 bucket_iterator bucket_end(unsigned hash) { 279 return bucket_iterator(Buckets + (hash & (NumBuckets-1)), true); 280 } 281 282 /// GetOrInsertNode - If there is an existing simple Node exactly 283 /// equal to the specified node, return it. Otherwise, insert 'N' and 284 /// return it instead. 285 T *GetOrInsertNode(Node *N) { 286 return static_cast<T *>(FoldingSetImpl::GetOrInsertNode(N)); 287 } 288 289 /// FindNodeOrInsertPos - Look up the node specified by ID. If it exists, 290 /// return it. If not, return the insertion token that will make insertion 291 /// faster. 292 T *FindNodeOrInsertPos(const FoldingSetNodeID &ID, void *&InsertPos) { 293 return static_cast<T *>(FoldingSetImpl::FindNodeOrInsertPos(ID, InsertPos)); 294 } 295}; 296 297//===----------------------------------------------------------------------===// 298/// FoldingSetIteratorImpl - This is the common iterator support shared by all 299/// folding sets, which knows how to walk the folding set hash table. 300class FoldingSetIteratorImpl { 301protected: 302 FoldingSetNode *NodePtr; 303 FoldingSetIteratorImpl(void **Bucket); 304 void advance(); 305 306public: 307 bool operator==(const FoldingSetIteratorImpl &RHS) const { 308 return NodePtr == RHS.NodePtr; 309 } 310 bool operator!=(const FoldingSetIteratorImpl &RHS) const { 311 return NodePtr != RHS.NodePtr; 312 } 313}; 314 315 316template<class T> 317class FoldingSetIterator : public FoldingSetIteratorImpl { 318public: 319 FoldingSetIterator(void **Bucket) : FoldingSetIteratorImpl(Bucket) {} 320 321 T &operator*() const { 322 return *static_cast<T*>(NodePtr); 323 } 324 325 T *operator->() const { 326 return static_cast<T*>(NodePtr); 327 } 328 329 inline FoldingSetIterator& operator++() { // Preincrement 330 advance(); 331 return *this; 332 } 333 FoldingSetIterator operator++(int) { // Postincrement 334 FoldingSetIterator tmp = *this; ++*this; return tmp; 335 } 336}; 337 338//===----------------------------------------------------------------------===// 339/// FoldingSetBucketIteratorImpl - This is the common bucket iterator support 340/// shared by all folding sets, which knows how to walk a particular bucket 341/// of a folding set hash table. 342 343class FoldingSetBucketIteratorImpl { 344protected: 345 void *Ptr; 346 347 FoldingSetBucketIteratorImpl(void **Bucket); 348 349 FoldingSetBucketIteratorImpl(void **Bucket, bool) 350 : Ptr(reinterpret_cast<void*>(Bucket)) {} 351 352 void advance() { 353 void *Probe = static_cast<FoldingSetNode*>(Ptr)->getNextInBucket(); 354 uintptr_t x = reinterpret_cast<uintptr_t>(Probe) & ~0x1; 355 Ptr = reinterpret_cast<void*>(x); 356 } 357 358public: 359 bool operator==(const FoldingSetBucketIteratorImpl &RHS) const { 360 return Ptr == RHS.Ptr; 361 } 362 bool operator!=(const FoldingSetBucketIteratorImpl &RHS) const { 363 return Ptr != RHS.Ptr; 364 } 365}; 366 367 368template<class T> 369class FoldingSetBucketIterator : public FoldingSetBucketIteratorImpl { 370public: 371 FoldingSetBucketIterator(void **Bucket) : 372 FoldingSetBucketIteratorImpl(Bucket) {} 373 374 FoldingSetBucketIterator(void **Bucket, bool) : 375 FoldingSetBucketIteratorImpl(Bucket, true) {} 376 377 T& operator*() const { return *static_cast<T*>(Ptr); } 378 T* operator->() const { return static_cast<T*>(Ptr); } 379 380 inline FoldingSetBucketIterator& operator++() { // Preincrement 381 advance(); 382 return *this; 383 } 384 FoldingSetBucketIterator operator++(int) { // Postincrement 385 FoldingSetBucketIterator tmp = *this; ++*this; return tmp; 386 } 387}; 388 389//===----------------------------------------------------------------------===// 390/// FoldingSetNodeWrapper - This template class is used to "wrap" arbitrary 391/// types in an enclosing object so that they can be inserted into FoldingSets. 392template <typename T> 393class FoldingSetNodeWrapper : public FoldingSetNode { 394 T data; 395public: 396 FoldingSetNodeWrapper(const T& x) : data(x) {} 397 virtual ~FoldingSetNodeWrapper() {} 398 399 template<typename A1> 400 explicit FoldingSetNodeWrapper(const A1& a1) 401 : data(a1) {} 402 403 template <typename A1, typename A2> 404 explicit FoldingSetNodeWrapper(const A1& a1, const A2& a2) 405 : data(a1,a2) {} 406 407 template <typename A1, typename A2, typename A3> 408 explicit FoldingSetNodeWrapper(const A1& a1, const A2& a2, const A3& a3) 409 : data(a1,a2,a3) {} 410 411 template <typename A1, typename A2, typename A3, typename A4> 412 explicit FoldingSetNodeWrapper(const A1& a1, const A2& a2, const A3& a3, 413 const A4& a4) 414 : data(a1,a2,a3,a4) {} 415 416 template <typename A1, typename A2, typename A3, typename A4, typename A5> 417 explicit FoldingSetNodeWrapper(const A1& a1, const A2& a2, const A3& a3, 418 const A4& a4, const A5& a5) 419 : data(a1,a2,a3,a4,a5) {} 420 421 422 void Profile(FoldingSetNodeID& ID) { FoldingSetTrait<T>::Profile(data, ID); } 423 424 T& getValue() { return data; } 425 const T& getValue() const { return data; } 426 427 operator T&() { return data; } 428 operator const T&() const { return data; } 429}; 430 431//===----------------------------------------------------------------------===// 432// Partial specializations of FoldingSetTrait. 433 434template<typename T> struct FoldingSetTrait<T*> { 435 static inline void Profile(const T* X, FoldingSetNodeID& ID) { 436 ID.AddPointer(X); 437 } 438 static inline void Profile(T* X, FoldingSetNodeID& ID) { 439 ID.AddPointer(X); 440 } 441}; 442 443} // End of namespace llvm. 444 445 446#endif 447 448