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_HAS_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 for (unsigned i = 0; i < Size / BITWORD_SIZE; ++i) 142 if (Bits[i] != ~0UL) 143 return false; 144 145 // If bits remain check that they are ones. The unused bits are always zero. 146 if (unsigned Remainder = Size % BITWORD_SIZE) 147 return Bits[Size / BITWORD_SIZE] == (1UL << Remainder) - 1; 148 149 return true; 150 } 151 152 /// none - Returns true if none of the bits are set. 153 bool none() const { 154 return !any(); 155 } 156 157 /// find_first - Returns the index of the first set bit, -1 if none 158 /// of the bits are set. 159 int find_first() const { 160 for (unsigned i = 0; i < NumBitWords(size()); ++i) 161 if (Bits[i] != 0) { 162 if (sizeof(BitWord) == 4) 163 return i * BITWORD_SIZE + countTrailingZeros((uint32_t)Bits[i]); 164 if (sizeof(BitWord) == 8) 165 return i * BITWORD_SIZE + countTrailingZeros(Bits[i]); 166 llvm_unreachable("Unsupported!"); 167 } 168 return -1; 169 } 170 171 /// find_next - Returns the index of the next set bit following the 172 /// "Prev" bit. Returns -1 if the next set bit is not found. 173 int find_next(unsigned Prev) const { 174 ++Prev; 175 if (Prev >= Size) 176 return -1; 177 178 unsigned WordPos = Prev / BITWORD_SIZE; 179 unsigned BitPos = Prev % BITWORD_SIZE; 180 BitWord Copy = Bits[WordPos]; 181 // Mask off previous bits. 182 Copy &= ~0UL << BitPos; 183 184 if (Copy != 0) { 185 if (sizeof(BitWord) == 4) 186 return WordPos * BITWORD_SIZE + countTrailingZeros((uint32_t)Copy); 187 if (sizeof(BitWord) == 8) 188 return WordPos * BITWORD_SIZE + countTrailingZeros(Copy); 189 llvm_unreachable("Unsupported!"); 190 } 191 192 // Check subsequent words. 193 for (unsigned i = WordPos+1; i < NumBitWords(size()); ++i) 194 if (Bits[i] != 0) { 195 if (sizeof(BitWord) == 4) 196 return i * BITWORD_SIZE + countTrailingZeros((uint32_t)Bits[i]); 197 if (sizeof(BitWord) == 8) 198 return i * BITWORD_SIZE + countTrailingZeros(Bits[i]); 199 llvm_unreachable("Unsupported!"); 200 } 201 return -1; 202 } 203 204 /// clear - Clear all bits. 205 void clear() { 206 Size = 0; 207 } 208 209 /// resize - Grow or shrink the bitvector. 210 void resize(unsigned N, bool t = false) { 211 if (N > Capacity * BITWORD_SIZE) { 212 unsigned OldCapacity = Capacity; 213 grow(N); 214 init_words(&Bits[OldCapacity], (Capacity-OldCapacity), t); 215 } 216 217 // Set any old unused bits that are now included in the BitVector. This 218 // may set bits that are not included in the new vector, but we will clear 219 // them back out below. 220 if (N > Size) 221 set_unused_bits(t); 222 223 // Update the size, and clear out any bits that are now unused 224 unsigned OldSize = Size; 225 Size = N; 226 if (t || N < OldSize) 227 clear_unused_bits(); 228 } 229 230 void reserve(unsigned N) { 231 if (N > Capacity * BITWORD_SIZE) 232 grow(N); 233 } 234 235 // Set, reset, flip 236 BitVector &set() { 237 init_words(Bits, Capacity, true); 238 clear_unused_bits(); 239 return *this; 240 } 241 242 BitVector &set(unsigned Idx) { 243 Bits[Idx / BITWORD_SIZE] |= 1L << (Idx % BITWORD_SIZE); 244 return *this; 245 } 246 247 /// set - Efficiently set a range of bits in [I, E) 248 BitVector &set(unsigned I, unsigned E) { 249 assert(I <= E && "Attempted to set backwards range!"); 250 assert(E <= size() && "Attempted to set out-of-bounds range!"); 251 252 if (I == E) return *this; 253 254 if (I / BITWORD_SIZE == E / BITWORD_SIZE) { 255 BitWord EMask = 1UL << (E % BITWORD_SIZE); 256 BitWord IMask = 1UL << (I % BITWORD_SIZE); 257 BitWord Mask = EMask - IMask; 258 Bits[I / BITWORD_SIZE] |= Mask; 259 return *this; 260 } 261 262 BitWord PrefixMask = ~0UL << (I % BITWORD_SIZE); 263 Bits[I / BITWORD_SIZE] |= PrefixMask; 264 I = RoundUpToAlignment(I, BITWORD_SIZE); 265 266 for (; I + BITWORD_SIZE <= E; I += BITWORD_SIZE) 267 Bits[I / BITWORD_SIZE] = ~0UL; 268 269 BitWord PostfixMask = (1UL << (E % BITWORD_SIZE)) - 1; 270 Bits[I / BITWORD_SIZE] |= PostfixMask; 271 272 return *this; 273 } 274 275 BitVector &reset() { 276 init_words(Bits, Capacity, false); 277 return *this; 278 } 279 280 BitVector &reset(unsigned Idx) { 281 Bits[Idx / BITWORD_SIZE] &= ~(1L << (Idx % BITWORD_SIZE)); 282 return *this; 283 } 284 285 /// reset - Efficiently reset a range of bits in [I, E) 286 BitVector &reset(unsigned I, unsigned E) { 287 assert(I <= E && "Attempted to reset backwards range!"); 288 assert(E <= size() && "Attempted to reset out-of-bounds range!"); 289 290 if (I == E) return *this; 291 292 if (I / BITWORD_SIZE == E / BITWORD_SIZE) { 293 BitWord EMask = 1UL << (E % BITWORD_SIZE); 294 BitWord IMask = 1UL << (I % BITWORD_SIZE); 295 BitWord Mask = EMask - IMask; 296 Bits[I / BITWORD_SIZE] &= ~Mask; 297 return *this; 298 } 299 300 BitWord PrefixMask = ~0UL << (I % BITWORD_SIZE); 301 Bits[I / BITWORD_SIZE] &= ~PrefixMask; 302 I = RoundUpToAlignment(I, BITWORD_SIZE); 303 304 for (; I + BITWORD_SIZE <= E; I += BITWORD_SIZE) 305 Bits[I / BITWORD_SIZE] = 0UL; 306 307 BitWord PostfixMask = (1UL << (E % BITWORD_SIZE)) - 1; 308 Bits[I / BITWORD_SIZE] &= ~PostfixMask; 309 310 return *this; 311 } 312 313 BitVector &flip() { 314 for (unsigned i = 0; i < NumBitWords(size()); ++i) 315 Bits[i] = ~Bits[i]; 316 clear_unused_bits(); 317 return *this; 318 } 319 320 BitVector &flip(unsigned Idx) { 321 Bits[Idx / BITWORD_SIZE] ^= 1L << (Idx % BITWORD_SIZE); 322 return *this; 323 } 324 325 // Indexing. 326 reference operator[](unsigned Idx) { 327 assert (Idx < Size && "Out-of-bounds Bit access."); 328 return reference(*this, Idx); 329 } 330 331 bool operator[](unsigned Idx) const { 332 assert (Idx < Size && "Out-of-bounds Bit access."); 333 BitWord Mask = 1L << (Idx % BITWORD_SIZE); 334 return (Bits[Idx / BITWORD_SIZE] & Mask) != 0; 335 } 336 337 bool test(unsigned Idx) const { 338 return (*this)[Idx]; 339 } 340 341 /// Test if any common bits are set. 342 bool anyCommon(const BitVector &RHS) const { 343 unsigned ThisWords = NumBitWords(size()); 344 unsigned RHSWords = NumBitWords(RHS.size()); 345 for (unsigned i = 0, e = std::min(ThisWords, RHSWords); i != e; ++i) 346 if (Bits[i] & RHS.Bits[i]) 347 return true; 348 return false; 349 } 350 351 // Comparison operators. 352 bool operator==(const BitVector &RHS) const { 353 unsigned ThisWords = NumBitWords(size()); 354 unsigned RHSWords = NumBitWords(RHS.size()); 355 unsigned i; 356 for (i = 0; i != std::min(ThisWords, RHSWords); ++i) 357 if (Bits[i] != RHS.Bits[i]) 358 return false; 359 360 // Verify that any extra words are all zeros. 361 if (i != ThisWords) { 362 for (; i != ThisWords; ++i) 363 if (Bits[i]) 364 return false; 365 } else if (i != RHSWords) { 366 for (; i != RHSWords; ++i) 367 if (RHS.Bits[i]) 368 return false; 369 } 370 return true; 371 } 372 373 bool operator!=(const BitVector &RHS) const { 374 return !(*this == RHS); 375 } 376 377 /// Intersection, union, disjoint union. 378 BitVector &operator&=(const BitVector &RHS) { 379 unsigned ThisWords = NumBitWords(size()); 380 unsigned RHSWords = NumBitWords(RHS.size()); 381 unsigned i; 382 for (i = 0; i != std::min(ThisWords, RHSWords); ++i) 383 Bits[i] &= RHS.Bits[i]; 384 385 // Any bits that are just in this bitvector become zero, because they aren't 386 // in the RHS bit vector. Any words only in RHS are ignored because they 387 // are already zero in the LHS. 388 for (; i != ThisWords; ++i) 389 Bits[i] = 0; 390 391 return *this; 392 } 393 394 /// reset - Reset bits that are set in RHS. Same as *this &= ~RHS. 395 BitVector &reset(const BitVector &RHS) { 396 unsigned ThisWords = NumBitWords(size()); 397 unsigned RHSWords = NumBitWords(RHS.size()); 398 unsigned i; 399 for (i = 0; i != std::min(ThisWords, RHSWords); ++i) 400 Bits[i] &= ~RHS.Bits[i]; 401 return *this; 402 } 403 404 /// test - Check if (This - RHS) is zero. 405 /// This is the same as reset(RHS) and any(). 406 bool test(const BitVector &RHS) const { 407 unsigned ThisWords = NumBitWords(size()); 408 unsigned RHSWords = NumBitWords(RHS.size()); 409 unsigned i; 410 for (i = 0; i != std::min(ThisWords, RHSWords); ++i) 411 if ((Bits[i] & ~RHS.Bits[i]) != 0) 412 return true; 413 414 for (; i != ThisWords ; ++i) 415 if (Bits[i] != 0) 416 return true; 417 418 return false; 419 } 420 421 BitVector &operator|=(const BitVector &RHS) { 422 if (size() < RHS.size()) 423 resize(RHS.size()); 424 for (size_t i = 0, e = NumBitWords(RHS.size()); i != e; ++i) 425 Bits[i] |= RHS.Bits[i]; 426 return *this; 427 } 428 429 BitVector &operator^=(const BitVector &RHS) { 430 if (size() < RHS.size()) 431 resize(RHS.size()); 432 for (size_t i = 0, e = NumBitWords(RHS.size()); i != e; ++i) 433 Bits[i] ^= RHS.Bits[i]; 434 return *this; 435 } 436 437 // Assignment operator. 438 const BitVector &operator=(const BitVector &RHS) { 439 if (this == &RHS) return *this; 440 441 Size = RHS.size(); 442 unsigned RHSWords = NumBitWords(Size); 443 if (Size <= Capacity * BITWORD_SIZE) { 444 if (Size) 445 std::memcpy(Bits, RHS.Bits, RHSWords * sizeof(BitWord)); 446 clear_unused_bits(); 447 return *this; 448 } 449 450 // Grow the bitvector to have enough elements. 451 Capacity = RHSWords; 452 BitWord *NewBits = (BitWord *)std::malloc(Capacity * sizeof(BitWord)); 453 std::memcpy(NewBits, RHS.Bits, Capacity * sizeof(BitWord)); 454 455 // Destroy the old bits. 456 std::free(Bits); 457 Bits = NewBits; 458 459 return *this; 460 } 461 462#if LLVM_HAS_RVALUE_REFERENCES 463 const BitVector &operator=(BitVector &&RHS) { 464 if (this == &RHS) return *this; 465 466 std::free(Bits); 467 Bits = RHS.Bits; 468 Size = RHS.Size; 469 Capacity = RHS.Capacity; 470 471 RHS.Bits = 0; 472 473 return *this; 474 } 475#endif 476 477 void swap(BitVector &RHS) { 478 std::swap(Bits, RHS.Bits); 479 std::swap(Size, RHS.Size); 480 std::swap(Capacity, RHS.Capacity); 481 } 482 483 //===--------------------------------------------------------------------===// 484 // Portable bit mask operations. 485 //===--------------------------------------------------------------------===// 486 // 487 // These methods all operate on arrays of uint32_t, each holding 32 bits. The 488 // fixed word size makes it easier to work with literal bit vector constants 489 // in portable code. 490 // 491 // The LSB in each word is the lowest numbered bit. The size of a portable 492 // bit mask is always a whole multiple of 32 bits. If no bit mask size is 493 // given, the bit mask is assumed to cover the entire BitVector. 494 495 /// setBitsInMask - Add '1' bits from Mask to this vector. Don't resize. 496 /// This computes "*this |= Mask". 497 void setBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) { 498 applyMask<true, false>(Mask, MaskWords); 499 } 500 501 /// clearBitsInMask - Clear any bits in this vector that are set in Mask. 502 /// Don't resize. This computes "*this &= ~Mask". 503 void clearBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) { 504 applyMask<false, false>(Mask, MaskWords); 505 } 506 507 /// setBitsNotInMask - Add a bit to this vector for every '0' bit in Mask. 508 /// Don't resize. This computes "*this |= ~Mask". 509 void setBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) { 510 applyMask<true, true>(Mask, MaskWords); 511 } 512 513 /// clearBitsNotInMask - Clear a bit in this vector for every '0' bit in Mask. 514 /// Don't resize. This computes "*this &= Mask". 515 void clearBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) { 516 applyMask<false, true>(Mask, MaskWords); 517 } 518 519private: 520 unsigned NumBitWords(unsigned S) const { 521 return (S + BITWORD_SIZE-1) / BITWORD_SIZE; 522 } 523 524 // Set the unused bits in the high words. 525 void set_unused_bits(bool t = true) { 526 // Set high words first. 527 unsigned UsedWords = NumBitWords(Size); 528 if (Capacity > UsedWords) 529 init_words(&Bits[UsedWords], (Capacity-UsedWords), t); 530 531 // Then set any stray high bits of the last used word. 532 unsigned ExtraBits = Size % BITWORD_SIZE; 533 if (ExtraBits) { 534 BitWord ExtraBitMask = ~0UL << ExtraBits; 535 if (t) 536 Bits[UsedWords-1] |= ExtraBitMask; 537 else 538 Bits[UsedWords-1] &= ~ExtraBitMask; 539 } 540 } 541 542 // Clear the unused bits in the high words. 543 void clear_unused_bits() { 544 set_unused_bits(false); 545 } 546 547 void grow(unsigned NewSize) { 548 Capacity = std::max(NumBitWords(NewSize), Capacity * 2); 549 Bits = (BitWord *)std::realloc(Bits, Capacity * sizeof(BitWord)); 550 551 clear_unused_bits(); 552 } 553 554 void init_words(BitWord *B, unsigned NumWords, bool t) { 555 memset(B, 0 - (int)t, NumWords*sizeof(BitWord)); 556 } 557 558 template<bool AddBits, bool InvertMask> 559 void applyMask(const uint32_t *Mask, unsigned MaskWords) { 560 assert(BITWORD_SIZE % 32 == 0 && "Unsupported BitWord size."); 561 MaskWords = std::min(MaskWords, (size() + 31) / 32); 562 const unsigned Scale = BITWORD_SIZE / 32; 563 unsigned i; 564 for (i = 0; MaskWords >= Scale; ++i, MaskWords -= Scale) { 565 BitWord BW = Bits[i]; 566 // This inner loop should unroll completely when BITWORD_SIZE > 32. 567 for (unsigned b = 0; b != BITWORD_SIZE; b += 32) { 568 uint32_t M = *Mask++; 569 if (InvertMask) M = ~M; 570 if (AddBits) BW |= BitWord(M) << b; 571 else BW &= ~(BitWord(M) << b); 572 } 573 Bits[i] = BW; 574 } 575 for (unsigned b = 0; MaskWords; b += 32, --MaskWords) { 576 uint32_t M = *Mask++; 577 if (InvertMask) M = ~M; 578 if (AddBits) Bits[i] |= BitWord(M) << b; 579 else Bits[i] &= ~(BitWord(M) << b); 580 } 581 if (AddBits) 582 clear_unused_bits(); 583 } 584}; 585 586} // End llvm namespace 587 588namespace std { 589 /// Implement std::swap in terms of BitVector swap. 590 inline void 591 swap(llvm::BitVector &LHS, llvm::BitVector &RHS) { 592 LHS.swap(RHS); 593 } 594} 595 596#endif 597