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 static_assert(BITWORD_SIZE == 64 || BITWORD_SIZE == 32, 33 "Unsupported word size"); 34 35 BitWord *Bits; // Actual bits. 36 unsigned Size; // Size of bitvector in bits. 37 unsigned Capacity; // Number of BitWords allocated in the Bits array. 38 39public: 40 typedef unsigned size_type; 41 // Encapsulation of a single bit. 42 class reference { 43 friend class BitVector; 44 45 BitWord *WordRef; 46 unsigned BitPos; 47 48 reference(); // Undefined 49 50 public: 51 reference(BitVector &b, unsigned Idx) { 52 WordRef = &b.Bits[Idx / BITWORD_SIZE]; 53 BitPos = Idx % BITWORD_SIZE; 54 } 55 56 reference(const reference&) = default; 57 58 reference &operator=(reference t) { 59 *this = bool(t); 60 return *this; 61 } 62 63 reference& operator=(bool t) { 64 if (t) 65 *WordRef |= BitWord(1) << BitPos; 66 else 67 *WordRef &= ~(BitWord(1) << BitPos); 68 return *this; 69 } 70 71 operator bool() const { 72 return ((*WordRef) & (BitWord(1) << BitPos)) ? true : false; 73 } 74 }; 75 76 77 /// BitVector default ctor - Creates an empty bitvector. 78 BitVector() : Size(0), Capacity(0) { 79 Bits = nullptr; 80 } 81 82 /// BitVector ctor - Creates a bitvector of specified number of bits. All 83 /// bits are initialized to the specified value. 84 explicit BitVector(unsigned s, bool t = false) : Size(s) { 85 Capacity = NumBitWords(s); 86 Bits = (BitWord *)std::malloc(Capacity * sizeof(BitWord)); 87 init_words(Bits, Capacity, t); 88 if (t) 89 clear_unused_bits(); 90 } 91 92 /// BitVector copy ctor. 93 BitVector(const BitVector &RHS) : Size(RHS.size()) { 94 if (Size == 0) { 95 Bits = nullptr; 96 Capacity = 0; 97 return; 98 } 99 100 Capacity = NumBitWords(RHS.size()); 101 Bits = (BitWord *)std::malloc(Capacity * sizeof(BitWord)); 102 std::memcpy(Bits, RHS.Bits, Capacity * sizeof(BitWord)); 103 } 104 105 BitVector(BitVector &&RHS) 106 : Bits(RHS.Bits), Size(RHS.Size), Capacity(RHS.Capacity) { 107 RHS.Bits = nullptr; 108 } 109 110 ~BitVector() { 111 std::free(Bits); 112 } 113 114 /// empty - Tests whether there are no bits in this bitvector. 115 bool empty() const { return Size == 0; } 116 117 /// size - Returns the number of bits in this bitvector. 118 size_type size() const { return Size; } 119 120 /// count - Returns the number of bits which are set. 121 size_type count() const { 122 unsigned NumBits = 0; 123 for (unsigned i = 0; i < NumBitWords(size()); ++i) 124 NumBits += countPopulation(Bits[i]); 125 return NumBits; 126 } 127 128 /// any - Returns true if any bit is set. 129 bool any() const { 130 for (unsigned i = 0; i < NumBitWords(size()); ++i) 131 if (Bits[i] != 0) 132 return true; 133 return false; 134 } 135 136 /// all - Returns true if all bits are set. 137 bool all() const { 138 for (unsigned i = 0; i < Size / BITWORD_SIZE; ++i) 139 if (Bits[i] != ~0UL) 140 return false; 141 142 // If bits remain check that they are ones. The unused bits are always zero. 143 if (unsigned Remainder = Size % BITWORD_SIZE) 144 return Bits[Size / BITWORD_SIZE] == (1UL << Remainder) - 1; 145 146 return true; 147 } 148 149 /// none - Returns true if none of the bits are set. 150 bool none() const { 151 return !any(); 152 } 153 154 /// find_first - Returns the index of the first set bit, -1 if none 155 /// of the bits are set. 156 int find_first() const { 157 for (unsigned i = 0; i < NumBitWords(size()); ++i) 158 if (Bits[i] != 0) 159 return i * BITWORD_SIZE + countTrailingZeros(Bits[i]); 160 return -1; 161 } 162 163 /// find_next - Returns the index of the next set bit following the 164 /// "Prev" bit. Returns -1 if the next set bit is not found. 165 int find_next(unsigned Prev) const { 166 ++Prev; 167 if (Prev >= Size) 168 return -1; 169 170 unsigned WordPos = Prev / BITWORD_SIZE; 171 unsigned BitPos = Prev % BITWORD_SIZE; 172 BitWord Copy = Bits[WordPos]; 173 // Mask off previous bits. 174 Copy &= ~0UL << BitPos; 175 176 if (Copy != 0) 177 return WordPos * BITWORD_SIZE + countTrailingZeros(Copy); 178 179 // Check subsequent words. 180 for (unsigned i = WordPos+1; i < NumBitWords(size()); ++i) 181 if (Bits[i] != 0) 182 return i * BITWORD_SIZE + countTrailingZeros(Bits[i]); 183 return -1; 184 } 185 186 /// clear - Clear all bits. 187 void clear() { 188 Size = 0; 189 } 190 191 /// resize - Grow or shrink the bitvector. 192 void resize(unsigned N, bool t = false) { 193 if (N > Capacity * BITWORD_SIZE) { 194 unsigned OldCapacity = Capacity; 195 grow(N); 196 init_words(&Bits[OldCapacity], (Capacity-OldCapacity), t); 197 } 198 199 // Set any old unused bits that are now included in the BitVector. This 200 // may set bits that are not included in the new vector, but we will clear 201 // them back out below. 202 if (N > Size) 203 set_unused_bits(t); 204 205 // Update the size, and clear out any bits that are now unused 206 unsigned OldSize = Size; 207 Size = N; 208 if (t || N < OldSize) 209 clear_unused_bits(); 210 } 211 212 void reserve(unsigned N) { 213 if (N > Capacity * BITWORD_SIZE) 214 grow(N); 215 } 216 217 // Set, reset, flip 218 BitVector &set() { 219 init_words(Bits, Capacity, true); 220 clear_unused_bits(); 221 return *this; 222 } 223 224 BitVector &set(unsigned Idx) { 225 assert(Bits && "Bits never allocated"); 226 Bits[Idx / BITWORD_SIZE] |= BitWord(1) << (Idx % BITWORD_SIZE); 227 return *this; 228 } 229 230 /// set - Efficiently set a range of bits in [I, E) 231 BitVector &set(unsigned I, unsigned E) { 232 assert(I <= E && "Attempted to set backwards range!"); 233 assert(E <= size() && "Attempted to set out-of-bounds range!"); 234 235 if (I == E) return *this; 236 237 if (I / BITWORD_SIZE == E / BITWORD_SIZE) { 238 BitWord EMask = 1UL << (E % BITWORD_SIZE); 239 BitWord IMask = 1UL << (I % BITWORD_SIZE); 240 BitWord Mask = EMask - IMask; 241 Bits[I / BITWORD_SIZE] |= Mask; 242 return *this; 243 } 244 245 BitWord PrefixMask = ~0UL << (I % BITWORD_SIZE); 246 Bits[I / BITWORD_SIZE] |= PrefixMask; 247 I = RoundUpToAlignment(I, BITWORD_SIZE); 248 249 for (; I + BITWORD_SIZE <= E; I += BITWORD_SIZE) 250 Bits[I / BITWORD_SIZE] = ~0UL; 251 252 BitWord PostfixMask = (1UL << (E % BITWORD_SIZE)) - 1; 253 if (I < E) 254 Bits[I / BITWORD_SIZE] |= PostfixMask; 255 256 return *this; 257 } 258 259 BitVector &reset() { 260 init_words(Bits, Capacity, false); 261 return *this; 262 } 263 264 BitVector &reset(unsigned Idx) { 265 Bits[Idx / BITWORD_SIZE] &= ~(BitWord(1) << (Idx % BITWORD_SIZE)); 266 return *this; 267 } 268 269 /// reset - Efficiently reset a range of bits in [I, E) 270 BitVector &reset(unsigned I, unsigned E) { 271 assert(I <= E && "Attempted to reset backwards range!"); 272 assert(E <= size() && "Attempted to reset out-of-bounds range!"); 273 274 if (I == E) return *this; 275 276 if (I / BITWORD_SIZE == E / BITWORD_SIZE) { 277 BitWord EMask = 1UL << (E % BITWORD_SIZE); 278 BitWord IMask = 1UL << (I % BITWORD_SIZE); 279 BitWord Mask = EMask - IMask; 280 Bits[I / BITWORD_SIZE] &= ~Mask; 281 return *this; 282 } 283 284 BitWord PrefixMask = ~0UL << (I % BITWORD_SIZE); 285 Bits[I / BITWORD_SIZE] &= ~PrefixMask; 286 I = RoundUpToAlignment(I, BITWORD_SIZE); 287 288 for (; I + BITWORD_SIZE <= E; I += BITWORD_SIZE) 289 Bits[I / BITWORD_SIZE] = 0UL; 290 291 BitWord PostfixMask = (1UL << (E % BITWORD_SIZE)) - 1; 292 if (I < E) 293 Bits[I / BITWORD_SIZE] &= ~PostfixMask; 294 295 return *this; 296 } 297 298 BitVector &flip() { 299 for (unsigned i = 0; i < NumBitWords(size()); ++i) 300 Bits[i] = ~Bits[i]; 301 clear_unused_bits(); 302 return *this; 303 } 304 305 BitVector &flip(unsigned Idx) { 306 Bits[Idx / BITWORD_SIZE] ^= BitWord(1) << (Idx % BITWORD_SIZE); 307 return *this; 308 } 309 310 // Indexing. 311 reference operator[](unsigned Idx) { 312 assert (Idx < Size && "Out-of-bounds Bit access."); 313 return reference(*this, Idx); 314 } 315 316 bool operator[](unsigned Idx) const { 317 assert (Idx < Size && "Out-of-bounds Bit access."); 318 BitWord Mask = BitWord(1) << (Idx % BITWORD_SIZE); 319 return (Bits[Idx / BITWORD_SIZE] & Mask) != 0; 320 } 321 322 bool test(unsigned Idx) const { 323 return (*this)[Idx]; 324 } 325 326 /// Test if any common bits are set. 327 bool anyCommon(const BitVector &RHS) const { 328 unsigned ThisWords = NumBitWords(size()); 329 unsigned RHSWords = NumBitWords(RHS.size()); 330 for (unsigned i = 0, e = std::min(ThisWords, RHSWords); i != e; ++i) 331 if (Bits[i] & RHS.Bits[i]) 332 return true; 333 return false; 334 } 335 336 // Comparison operators. 337 bool operator==(const BitVector &RHS) const { 338 unsigned ThisWords = NumBitWords(size()); 339 unsigned RHSWords = NumBitWords(RHS.size()); 340 unsigned i; 341 for (i = 0; i != std::min(ThisWords, RHSWords); ++i) 342 if (Bits[i] != RHS.Bits[i]) 343 return false; 344 345 // Verify that any extra words are all zeros. 346 if (i != ThisWords) { 347 for (; i != ThisWords; ++i) 348 if (Bits[i]) 349 return false; 350 } else if (i != RHSWords) { 351 for (; i != RHSWords; ++i) 352 if (RHS.Bits[i]) 353 return false; 354 } 355 return true; 356 } 357 358 bool operator!=(const BitVector &RHS) const { 359 return !(*this == RHS); 360 } 361 362 /// Intersection, union, disjoint union. 363 BitVector &operator&=(const BitVector &RHS) { 364 unsigned ThisWords = NumBitWords(size()); 365 unsigned RHSWords = NumBitWords(RHS.size()); 366 unsigned i; 367 for (i = 0; i != std::min(ThisWords, RHSWords); ++i) 368 Bits[i] &= RHS.Bits[i]; 369 370 // Any bits that are just in this bitvector become zero, because they aren't 371 // in the RHS bit vector. Any words only in RHS are ignored because they 372 // are already zero in the LHS. 373 for (; i != ThisWords; ++i) 374 Bits[i] = 0; 375 376 return *this; 377 } 378 379 /// reset - Reset bits that are set in RHS. Same as *this &= ~RHS. 380 BitVector &reset(const BitVector &RHS) { 381 unsigned ThisWords = NumBitWords(size()); 382 unsigned RHSWords = NumBitWords(RHS.size()); 383 unsigned i; 384 for (i = 0; i != std::min(ThisWords, RHSWords); ++i) 385 Bits[i] &= ~RHS.Bits[i]; 386 return *this; 387 } 388 389 /// test - Check if (This - RHS) is zero. 390 /// This is the same as reset(RHS) and any(). 391 bool test(const BitVector &RHS) const { 392 unsigned ThisWords = NumBitWords(size()); 393 unsigned RHSWords = NumBitWords(RHS.size()); 394 unsigned i; 395 for (i = 0; i != std::min(ThisWords, RHSWords); ++i) 396 if ((Bits[i] & ~RHS.Bits[i]) != 0) 397 return true; 398 399 for (; i != ThisWords ; ++i) 400 if (Bits[i] != 0) 401 return true; 402 403 return false; 404 } 405 406 BitVector &operator|=(const BitVector &RHS) { 407 if (size() < RHS.size()) 408 resize(RHS.size()); 409 for (size_t i = 0, e = NumBitWords(RHS.size()); i != e; ++i) 410 Bits[i] |= RHS.Bits[i]; 411 return *this; 412 } 413 414 BitVector &operator^=(const BitVector &RHS) { 415 if (size() < RHS.size()) 416 resize(RHS.size()); 417 for (size_t i = 0, e = NumBitWords(RHS.size()); i != e; ++i) 418 Bits[i] ^= RHS.Bits[i]; 419 return *this; 420 } 421 422 // Assignment operator. 423 const BitVector &operator=(const BitVector &RHS) { 424 if (this == &RHS) return *this; 425 426 Size = RHS.size(); 427 unsigned RHSWords = NumBitWords(Size); 428 if (Size <= Capacity * BITWORD_SIZE) { 429 if (Size) 430 std::memcpy(Bits, RHS.Bits, RHSWords * sizeof(BitWord)); 431 clear_unused_bits(); 432 return *this; 433 } 434 435 // Grow the bitvector to have enough elements. 436 Capacity = RHSWords; 437 assert(Capacity > 0 && "negative capacity?"); 438 BitWord *NewBits = (BitWord *)std::malloc(Capacity * sizeof(BitWord)); 439 std::memcpy(NewBits, RHS.Bits, Capacity * sizeof(BitWord)); 440 441 // Destroy the old bits. 442 std::free(Bits); 443 Bits = NewBits; 444 445 return *this; 446 } 447 448 const BitVector &operator=(BitVector &&RHS) { 449 if (this == &RHS) return *this; 450 451 std::free(Bits); 452 Bits = RHS.Bits; 453 Size = RHS.Size; 454 Capacity = RHS.Capacity; 455 456 RHS.Bits = nullptr; 457 458 return *this; 459 } 460 461 void swap(BitVector &RHS) { 462 std::swap(Bits, RHS.Bits); 463 std::swap(Size, RHS.Size); 464 std::swap(Capacity, RHS.Capacity); 465 } 466 467 //===--------------------------------------------------------------------===// 468 // Portable bit mask operations. 469 //===--------------------------------------------------------------------===// 470 // 471 // These methods all operate on arrays of uint32_t, each holding 32 bits. The 472 // fixed word size makes it easier to work with literal bit vector constants 473 // in portable code. 474 // 475 // The LSB in each word is the lowest numbered bit. The size of a portable 476 // bit mask is always a whole multiple of 32 bits. If no bit mask size is 477 // given, the bit mask is assumed to cover the entire BitVector. 478 479 /// setBitsInMask - Add '1' bits from Mask to this vector. Don't resize. 480 /// This computes "*this |= Mask". 481 void setBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) { 482 applyMask<true, false>(Mask, MaskWords); 483 } 484 485 /// clearBitsInMask - Clear any bits in this vector that are set in Mask. 486 /// Don't resize. This computes "*this &= ~Mask". 487 void clearBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) { 488 applyMask<false, false>(Mask, MaskWords); 489 } 490 491 /// setBitsNotInMask - Add a bit to this vector for every '0' bit in Mask. 492 /// Don't resize. This computes "*this |= ~Mask". 493 void setBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) { 494 applyMask<true, true>(Mask, MaskWords); 495 } 496 497 /// clearBitsNotInMask - Clear a bit in this vector for every '0' bit in Mask. 498 /// Don't resize. This computes "*this &= Mask". 499 void clearBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) { 500 applyMask<false, true>(Mask, MaskWords); 501 } 502 503private: 504 unsigned NumBitWords(unsigned S) const { 505 return (S + BITWORD_SIZE-1) / BITWORD_SIZE; 506 } 507 508 // Set the unused bits in the high words. 509 void set_unused_bits(bool t = true) { 510 // Set high words first. 511 unsigned UsedWords = NumBitWords(Size); 512 if (Capacity > UsedWords) 513 init_words(&Bits[UsedWords], (Capacity-UsedWords), t); 514 515 // Then set any stray high bits of the last used word. 516 unsigned ExtraBits = Size % BITWORD_SIZE; 517 if (ExtraBits) { 518 BitWord ExtraBitMask = ~0UL << ExtraBits; 519 if (t) 520 Bits[UsedWords-1] |= ExtraBitMask; 521 else 522 Bits[UsedWords-1] &= ~ExtraBitMask; 523 } 524 } 525 526 // Clear the unused bits in the high words. 527 void clear_unused_bits() { 528 set_unused_bits(false); 529 } 530 531 void grow(unsigned NewSize) { 532 Capacity = std::max(NumBitWords(NewSize), Capacity * 2); 533 assert(Capacity > 0 && "realloc-ing zero space"); 534 Bits = (BitWord *)std::realloc(Bits, Capacity * sizeof(BitWord)); 535 536 clear_unused_bits(); 537 } 538 539 void init_words(BitWord *B, unsigned NumWords, bool t) { 540 memset(B, 0 - (int)t, NumWords*sizeof(BitWord)); 541 } 542 543 template<bool AddBits, bool InvertMask> 544 void applyMask(const uint32_t *Mask, unsigned MaskWords) { 545 static_assert(BITWORD_SIZE % 32 == 0, "Unsupported BitWord size."); 546 MaskWords = std::min(MaskWords, (size() + 31) / 32); 547 const unsigned Scale = BITWORD_SIZE / 32; 548 unsigned i; 549 for (i = 0; MaskWords >= Scale; ++i, MaskWords -= Scale) { 550 BitWord BW = Bits[i]; 551 // This inner loop should unroll completely when BITWORD_SIZE > 32. 552 for (unsigned b = 0; b != BITWORD_SIZE; b += 32) { 553 uint32_t M = *Mask++; 554 if (InvertMask) M = ~M; 555 if (AddBits) BW |= BitWord(M) << b; 556 else BW &= ~(BitWord(M) << b); 557 } 558 Bits[i] = BW; 559 } 560 for (unsigned b = 0; MaskWords; b += 32, --MaskWords) { 561 uint32_t M = *Mask++; 562 if (InvertMask) M = ~M; 563 if (AddBits) Bits[i] |= BitWord(M) << b; 564 else Bits[i] &= ~(BitWord(M) << b); 565 } 566 if (AddBits) 567 clear_unused_bits(); 568 } 569 570public: 571 /// Return the size (in bytes) of the bit vector. 572 size_t getMemorySize() const { return Capacity * sizeof(BitWord); } 573}; 574 575static inline size_t capacity_in_bytes(const BitVector &X) { 576 return X.getMemorySize(); 577} 578 579} // End llvm namespace 580 581namespace std { 582 /// Implement std::swap in terms of BitVector swap. 583 inline void 584 swap(llvm::BitVector &LHS, llvm::BitVector &RHS) { 585 LHS.swap(RHS); 586 } 587} 588 589#endif 590