BitVector.h revision 693e3ee0c2d2a2cb6f691222694a788dd595c108
1//===- llvm/ADT/BitVector.h - Bit vectors -----------------------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements the BitVector class. 11// 12//===----------------------------------------------------------------------===// 13 14#ifndef LLVM_ADT_BITVECTOR_H 15#define LLVM_ADT_BITVECTOR_H 16 17#include "llvm/Support/Compiler.h" 18#include "llvm/Support/ErrorHandling.h" 19#include "llvm/Support/MathExtras.h" 20#include <algorithm> 21#include <cassert> 22#include <climits> 23#include <cstdlib> 24 25namespace llvm { 26 27class BitVector { 28 typedef unsigned long BitWord; 29 30 enum { BITWORD_SIZE = (unsigned)sizeof(BitWord) * CHAR_BIT }; 31 32 BitWord *Bits; // Actual bits. 33 unsigned Size; // Size of bitvector in bits. 34 unsigned Capacity; // Size of allocated memory in BitWord. 35 36public: 37 // Encapsulation of a single bit. 38 class reference { 39 friend class BitVector; 40 41 BitWord *WordRef; 42 unsigned BitPos; 43 44 reference(); // Undefined 45 46 public: 47 reference(BitVector &b, unsigned Idx) { 48 WordRef = &b.Bits[Idx / BITWORD_SIZE]; 49 BitPos = Idx % BITWORD_SIZE; 50 } 51 52 ~reference() {} 53 54 reference &operator=(reference t) { 55 *this = bool(t); 56 return *this; 57 } 58 59 reference& operator=(bool t) { 60 if (t) 61 *WordRef |= 1L << BitPos; 62 else 63 *WordRef &= ~(1L << BitPos); 64 return *this; 65 } 66 67 operator bool() const { 68 return ((*WordRef) & (1L << BitPos)) ? true : false; 69 } 70 }; 71 72 73 /// BitVector default ctor - Creates an empty bitvector. 74 BitVector() : Size(0), Capacity(0) { 75 Bits = 0; 76 } 77 78 /// BitVector ctor - Creates a bitvector of specified number of bits. All 79 /// bits are initialized to the specified value. 80 explicit BitVector(unsigned s, bool t = false) : Size(s) { 81 Capacity = NumBitWords(s); 82 Bits = (BitWord *)std::malloc(Capacity * sizeof(BitWord)); 83 init_words(Bits, Capacity, t); 84 if (t) 85 clear_unused_bits(); 86 } 87 88 /// BitVector copy ctor. 89 BitVector(const BitVector &RHS) : Size(RHS.size()) { 90 if (Size == 0) { 91 Bits = 0; 92 Capacity = 0; 93 return; 94 } 95 96 Capacity = NumBitWords(RHS.size()); 97 Bits = (BitWord *)std::malloc(Capacity * sizeof(BitWord)); 98 std::memcpy(Bits, RHS.Bits, Capacity * sizeof(BitWord)); 99 } 100 101#if LLVM_USE_RVALUE_REFERENCES 102 BitVector(BitVector &&RHS) 103 : Bits(RHS.Bits), Size(RHS.Size), Capacity(RHS.Capacity) { 104 RHS.Bits = 0; 105 } 106#endif 107 108 ~BitVector() { 109 std::free(Bits); 110 } 111 112 /// empty - Tests whether there are no bits in this bitvector. 113 bool empty() const { return Size == 0; } 114 115 /// size - Returns the number of bits in this bitvector. 116 unsigned size() const { return Size; } 117 118 /// count - Returns the number of bits which are set. 119 unsigned count() const { 120 unsigned NumBits = 0; 121 for (unsigned i = 0; i < NumBitWords(size()); ++i) 122 if (sizeof(BitWord) == 4) 123 NumBits += CountPopulation_32((uint32_t)Bits[i]); 124 else if (sizeof(BitWord) == 8) 125 NumBits += CountPopulation_64(Bits[i]); 126 else 127 llvm_unreachable("Unsupported!"); 128 return NumBits; 129 } 130 131 /// any - Returns true if any bit is set. 132 bool any() const { 133 for (unsigned i = 0; i < NumBitWords(size()); ++i) 134 if (Bits[i] != 0) 135 return true; 136 return false; 137 } 138 139 /// all - Returns true if all bits are set. 140 bool all() const { 141 // TODO: Optimize this. 142 return count() == size(); 143 } 144 145 /// none - Returns true if none of the bits are set. 146 bool none() const { 147 return !any(); 148 } 149 150 /// find_first - Returns the index of the first set bit, -1 if none 151 /// of the bits are set. 152 int find_first() const { 153 for (unsigned i = 0; i < NumBitWords(size()); ++i) 154 if (Bits[i] != 0) { 155 if (sizeof(BitWord) == 4) 156 return i * BITWORD_SIZE + CountTrailingZeros_32((uint32_t)Bits[i]); 157 if (sizeof(BitWord) == 8) 158 return i * BITWORD_SIZE + CountTrailingZeros_64(Bits[i]); 159 llvm_unreachable("Unsupported!"); 160 } 161 return -1; 162 } 163 164 /// find_next - Returns the index of the next set bit following the 165 /// "Prev" bit. Returns -1 if the next set bit is not found. 166 int find_next(unsigned Prev) const { 167 ++Prev; 168 if (Prev >= Size) 169 return -1; 170 171 unsigned WordPos = Prev / BITWORD_SIZE; 172 unsigned BitPos = Prev % BITWORD_SIZE; 173 BitWord Copy = Bits[WordPos]; 174 // Mask off previous bits. 175 Copy &= ~0L << BitPos; 176 177 if (Copy != 0) { 178 if (sizeof(BitWord) == 4) 179 return WordPos * BITWORD_SIZE + CountTrailingZeros_32((uint32_t)Copy); 180 if (sizeof(BitWord) == 8) 181 return WordPos * BITWORD_SIZE + CountTrailingZeros_64(Copy); 182 llvm_unreachable("Unsupported!"); 183 } 184 185 // Check subsequent words. 186 for (unsigned i = WordPos+1; i < NumBitWords(size()); ++i) 187 if (Bits[i] != 0) { 188 if (sizeof(BitWord) == 4) 189 return i * BITWORD_SIZE + CountTrailingZeros_32((uint32_t)Bits[i]); 190 if (sizeof(BitWord) == 8) 191 return i * BITWORD_SIZE + CountTrailingZeros_64(Bits[i]); 192 llvm_unreachable("Unsupported!"); 193 } 194 return -1; 195 } 196 197 /// clear - Clear all bits. 198 void clear() { 199 Size = 0; 200 } 201 202 /// resize - Grow or shrink the bitvector. 203 void resize(unsigned N, bool t = false) { 204 if (N > Capacity * BITWORD_SIZE) { 205 unsigned OldCapacity = Capacity; 206 grow(N); 207 init_words(&Bits[OldCapacity], (Capacity-OldCapacity), t); 208 } 209 210 // Set any old unused bits that are now included in the BitVector. This 211 // may set bits that are not included in the new vector, but we will clear 212 // them back out below. 213 if (N > Size) 214 set_unused_bits(t); 215 216 // Update the size, and clear out any bits that are now unused 217 unsigned OldSize = Size; 218 Size = N; 219 if (t || N < OldSize) 220 clear_unused_bits(); 221 } 222 223 void reserve(unsigned N) { 224 if (N > Capacity * BITWORD_SIZE) 225 grow(N); 226 } 227 228 // Set, reset, flip 229 BitVector &set() { 230 init_words(Bits, Capacity, true); 231 clear_unused_bits(); 232 return *this; 233 } 234 235 BitVector &set(unsigned Idx) { 236 Bits[Idx / BITWORD_SIZE] |= 1L << (Idx % BITWORD_SIZE); 237 return *this; 238 } 239 240 BitVector &reset() { 241 init_words(Bits, Capacity, false); 242 return *this; 243 } 244 245 BitVector &reset(unsigned Idx) { 246 Bits[Idx / BITWORD_SIZE] &= ~(1L << (Idx % BITWORD_SIZE)); 247 return *this; 248 } 249 250 BitVector &flip() { 251 for (unsigned i = 0; i < NumBitWords(size()); ++i) 252 Bits[i] = ~Bits[i]; 253 clear_unused_bits(); 254 return *this; 255 } 256 257 BitVector &flip(unsigned Idx) { 258 Bits[Idx / BITWORD_SIZE] ^= 1L << (Idx % BITWORD_SIZE); 259 return *this; 260 } 261 262 // Indexing. 263 reference operator[](unsigned Idx) { 264 assert (Idx < Size && "Out-of-bounds Bit access."); 265 return reference(*this, Idx); 266 } 267 268 bool operator[](unsigned Idx) const { 269 assert (Idx < Size && "Out-of-bounds Bit access."); 270 BitWord Mask = 1L << (Idx % BITWORD_SIZE); 271 return (Bits[Idx / BITWORD_SIZE] & Mask) != 0; 272 } 273 274 bool test(unsigned Idx) const { 275 return (*this)[Idx]; 276 } 277 278 /// Test if any common bits are set. 279 bool anyCommon(const BitVector &RHS) const { 280 unsigned ThisWords = NumBitWords(size()); 281 unsigned RHSWords = NumBitWords(RHS.size()); 282 for (unsigned i = 0, e = std::min(ThisWords, RHSWords); i != e; ++i) 283 if (Bits[i] & RHS.Bits[i]) 284 return true; 285 return false; 286 } 287 288 // Comparison operators. 289 bool operator==(const BitVector &RHS) const { 290 unsigned ThisWords = NumBitWords(size()); 291 unsigned RHSWords = NumBitWords(RHS.size()); 292 unsigned i; 293 for (i = 0; i != std::min(ThisWords, RHSWords); ++i) 294 if (Bits[i] != RHS.Bits[i]) 295 return false; 296 297 // Verify that any extra words are all zeros. 298 if (i != ThisWords) { 299 for (; i != ThisWords; ++i) 300 if (Bits[i]) 301 return false; 302 } else if (i != RHSWords) { 303 for (; i != RHSWords; ++i) 304 if (RHS.Bits[i]) 305 return false; 306 } 307 return true; 308 } 309 310 bool operator!=(const BitVector &RHS) const { 311 return !(*this == RHS); 312 } 313 314 // Intersection, union, disjoint union. 315 BitVector &operator&=(const BitVector &RHS) { 316 unsigned ThisWords = NumBitWords(size()); 317 unsigned RHSWords = NumBitWords(RHS.size()); 318 unsigned i; 319 for (i = 0; i != std::min(ThisWords, RHSWords); ++i) 320 Bits[i] &= RHS.Bits[i]; 321 322 // Any bits that are just in this bitvector become zero, because they aren't 323 // in the RHS bit vector. Any words only in RHS are ignored because they 324 // are already zero in the LHS. 325 for (; i != ThisWords; ++i) 326 Bits[i] = 0; 327 328 return *this; 329 } 330 331 // reset - Reset bits that are set in RHS. Same as *this &= ~RHS. 332 BitVector &reset(const BitVector &RHS) { 333 unsigned ThisWords = NumBitWords(size()); 334 unsigned RHSWords = NumBitWords(RHS.size()); 335 unsigned i; 336 for (i = 0; i != std::min(ThisWords, RHSWords); ++i) 337 Bits[i] &= ~RHS.Bits[i]; 338 return *this; 339 } 340 341 BitVector &operator|=(const BitVector &RHS) { 342 if (size() < RHS.size()) 343 resize(RHS.size()); 344 for (size_t i = 0, e = NumBitWords(RHS.size()); i != e; ++i) 345 Bits[i] |= RHS.Bits[i]; 346 return *this; 347 } 348 349 BitVector &operator^=(const BitVector &RHS) { 350 if (size() < RHS.size()) 351 resize(RHS.size()); 352 for (size_t i = 0, e = NumBitWords(RHS.size()); i != e; ++i) 353 Bits[i] ^= RHS.Bits[i]; 354 return *this; 355 } 356 357 // Assignment operator. 358 const BitVector &operator=(const BitVector &RHS) { 359 if (this == &RHS) return *this; 360 361 Size = RHS.size(); 362 unsigned RHSWords = NumBitWords(Size); 363 if (Size <= Capacity * BITWORD_SIZE) { 364 if (Size) 365 std::memcpy(Bits, RHS.Bits, RHSWords * sizeof(BitWord)); 366 clear_unused_bits(); 367 return *this; 368 } 369 370 // Grow the bitvector to have enough elements. 371 Capacity = RHSWords; 372 BitWord *NewBits = (BitWord *)std::malloc(Capacity * sizeof(BitWord)); 373 std::memcpy(NewBits, RHS.Bits, Capacity * sizeof(BitWord)); 374 375 // Destroy the old bits. 376 std::free(Bits); 377 Bits = NewBits; 378 379 return *this; 380 } 381 382#if LLVM_USE_RVALUE_REFERENCES 383 const BitVector &operator=(BitVector &&RHS) { 384 if (this == &RHS) return *this; 385 386 std::free(Bits); 387 Bits = RHS.Bits; 388 Size = RHS.Size; 389 Capacity = RHS.Capacity; 390 391 RHS.Bits = 0; 392 393 return *this; 394 } 395#endif 396 397 void swap(BitVector &RHS) { 398 std::swap(Bits, RHS.Bits); 399 std::swap(Size, RHS.Size); 400 std::swap(Capacity, RHS.Capacity); 401 } 402 403 //===--------------------------------------------------------------------===// 404 // Portable bit mask operations. 405 //===--------------------------------------------------------------------===// 406 // 407 // These methods all operate on arrays of uint32_t, each holding 32 bits. The 408 // fixed word size makes it easier to work with literal bit vector constants 409 // in portable code. 410 // 411 // The LSB in each word is the lowest numbered bit. The size of a portable 412 // bit mask is always a whole multiple of 32 bits. If no bit mask size is 413 // given, the bit mask is assumed to cover the entire BitVector. 414 415 /// setBitsInMask - Add '1' bits from Mask to this vector. Don't resize. 416 /// This computes "*this |= Mask". 417 void setBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) { 418 applyMask<true, false>(Mask, MaskWords); 419 } 420 421 /// clearBitsInMask - Clear any bits in this vector that are set in Mask. 422 /// Don't resize. This computes "*this &= ~Mask". 423 void clearBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) { 424 applyMask<false, false>(Mask, MaskWords); 425 } 426 427 /// setBitsNotInMask - Add a bit to this vector for every '0' bit in Mask. 428 /// Don't resize. This computes "*this |= ~Mask". 429 void setBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) { 430 applyMask<true, true>(Mask, MaskWords); 431 } 432 433 /// clearBitsNotInMask - Clear a bit in this vector for every '0' bit in Mask. 434 /// Don't resize. This computes "*this &= Mask". 435 void clearBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) { 436 applyMask<false, true>(Mask, MaskWords); 437 } 438 439private: 440 unsigned NumBitWords(unsigned S) const { 441 return (S + BITWORD_SIZE-1) / BITWORD_SIZE; 442 } 443 444 // Set the unused bits in the high words. 445 void set_unused_bits(bool t = true) { 446 // Set high words first. 447 unsigned UsedWords = NumBitWords(Size); 448 if (Capacity > UsedWords) 449 init_words(&Bits[UsedWords], (Capacity-UsedWords), t); 450 451 // Then set any stray high bits of the last used word. 452 unsigned ExtraBits = Size % BITWORD_SIZE; 453 if (ExtraBits) { 454 Bits[UsedWords-1] &= ~(~0L << ExtraBits); 455 Bits[UsedWords-1] |= (0 - (BitWord)t) << ExtraBits; 456 } 457 } 458 459 // Clear the unused bits in the high words. 460 void clear_unused_bits() { 461 set_unused_bits(false); 462 } 463 464 void grow(unsigned NewSize) { 465 Capacity = std::max(NumBitWords(NewSize), Capacity * 2); 466 Bits = (BitWord *)std::realloc(Bits, Capacity * sizeof(BitWord)); 467 468 clear_unused_bits(); 469 } 470 471 void init_words(BitWord *B, unsigned NumWords, bool t) { 472 memset(B, 0 - (int)t, NumWords*sizeof(BitWord)); 473 } 474 475 template<bool AddBits, bool InvertMask> 476 void applyMask(const uint32_t *Mask, unsigned MaskWords) { 477 assert(BITWORD_SIZE % 32 == 0 && "Unsupported BitWord size."); 478 MaskWords = std::min(MaskWords, (size() + 31) / 32); 479 const unsigned Scale = BITWORD_SIZE / 32; 480 unsigned i; 481 for (i = 0; MaskWords >= Scale; ++i, MaskWords -= Scale) { 482 BitWord BW = Bits[i]; 483 // This inner loop should unroll completely when BITWORD_SIZE > 32. 484 for (unsigned b = 0; b != BITWORD_SIZE; b += 32) { 485 uint32_t M = *Mask++; 486 if (InvertMask) M = ~M; 487 if (AddBits) BW |= BitWord(M) << b; 488 else BW &= ~(BitWord(M) << b); 489 } 490 Bits[i] = BW; 491 } 492 for (unsigned b = 0; MaskWords; b += 32, --MaskWords) { 493 uint32_t M = *Mask++; 494 if (InvertMask) M = ~M; 495 if (AddBits) Bits[i] |= BitWord(M) << b; 496 else Bits[i] &= ~(BitWord(M) << b); 497 } 498 if (AddBits) 499 clear_unused_bits(); 500 } 501}; 502 503} // End llvm namespace 504 505namespace std { 506 /// Implement std::swap in terms of BitVector swap. 507 inline void 508 swap(llvm::BitVector &LHS, llvm::BitVector &RHS) { 509 LHS.swap(RHS); 510 } 511} 512 513#endif 514