LLVM  10.0.0svn
BitVector.h
Go to the documentation of this file.
1 //===- llvm/ADT/BitVector.h - Bit vectors -----------------------*- 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 implements the BitVector class.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_ADT_BITVECTOR_H
14 #define LLVM_ADT_BITVECTOR_H
15 
16 #include "llvm/ADT/ArrayRef.h"
19 #include <algorithm>
20 #include <cassert>
21 #include <climits>
22 #include <cstdint>
23 #include <cstdlib>
24 #include <cstring>
25 #include <utility>
26 
27 namespace llvm {
28 
29 /// ForwardIterator for the bits that are set.
30 /// Iterators get invalidated when resize / reserve is called.
31 template <typename BitVectorT> class const_set_bits_iterator_impl {
32  const BitVectorT &Parent;
33  int Current = 0;
34 
35  void advance() {
36  assert(Current != -1 && "Trying to advance past end.");
37  Current = Parent.find_next(Current);
38  }
39 
40 public:
41  const_set_bits_iterator_impl(const BitVectorT &Parent, int Current)
42  : Parent(Parent), Current(Current) {}
43  explicit const_set_bits_iterator_impl(const BitVectorT &Parent)
44  : const_set_bits_iterator_impl(Parent, Parent.find_first()) {}
46 
48  auto Prev = *this;
49  advance();
50  return Prev;
51  }
52 
54  advance();
55  return *this;
56  }
57 
58  unsigned operator*() const { return Current; }
59 
60  bool operator==(const const_set_bits_iterator_impl &Other) const {
61  assert(&Parent == &Other.Parent &&
62  "Comparing iterators from different BitVectors");
63  return Current == Other.Current;
64  }
65 
66  bool operator!=(const const_set_bits_iterator_impl &Other) const {
67  assert(&Parent == &Other.Parent &&
68  "Comparing iterators from different BitVectors");
69  return Current != Other.Current;
70  }
71 };
72 
73 class BitVector {
74  typedef unsigned long BitWord;
75 
76  enum { BITWORD_SIZE = (unsigned)sizeof(BitWord) * CHAR_BIT };
77 
78  static_assert(BITWORD_SIZE == 64 || BITWORD_SIZE == 32,
79  "Unsupported word size");
80 
81  MutableArrayRef<BitWord> Bits; // Actual bits.
82  unsigned Size; // Size of bitvector in bits.
83 
84 public:
85  typedef unsigned size_type;
86  // Encapsulation of a single bit.
87  class reference {
88  friend class BitVector;
89 
90  BitWord *WordRef;
91  unsigned BitPos;
92 
93  public:
94  reference(BitVector &b, unsigned Idx) {
95  WordRef = &b.Bits[Idx / BITWORD_SIZE];
96  BitPos = Idx % BITWORD_SIZE;
97  }
98 
99  reference() = delete;
100  reference(const reference&) = default;
101 
103  *this = bool(t);
104  return *this;
105  }
106 
107  reference& operator=(bool t) {
108  if (t)
109  *WordRef |= BitWord(1) << BitPos;
110  else
111  *WordRef &= ~(BitWord(1) << BitPos);
112  return *this;
113  }
114 
115  operator bool() const {
116  return ((*WordRef) & (BitWord(1) << BitPos)) != 0;
117  }
118  };
119 
121  typedef const_set_bits_iterator set_iterator;
122 
123  const_set_bits_iterator set_bits_begin() const {
124  return const_set_bits_iterator(*this);
125  }
126  const_set_bits_iterator set_bits_end() const {
127  return const_set_bits_iterator(*this, -1);
128  }
130  return make_range(set_bits_begin(), set_bits_end());
131  }
132 
133  /// BitVector default ctor - Creates an empty bitvector.
134  BitVector() : Size(0) {}
135 
136  /// BitVector ctor - Creates a bitvector of specified number of bits. All
137  /// bits are initialized to the specified value.
138  explicit BitVector(unsigned s, bool t = false) : Size(s) {
139  size_t Capacity = NumBitWords(s);
140  Bits = allocate(Capacity);
141  init_words(Bits, t);
142  if (t)
143  clear_unused_bits();
144  }
145 
146  /// BitVector copy ctor.
147  BitVector(const BitVector &RHS) : Size(RHS.size()) {
148  if (Size == 0) {
149  Bits = MutableArrayRef<BitWord>();
150  return;
151  }
152 
153  size_t Capacity = NumBitWords(RHS.size());
154  Bits = allocate(Capacity);
155  std::memcpy(Bits.data(), RHS.Bits.data(), Capacity * sizeof(BitWord));
156  }
157 
158  BitVector(BitVector &&RHS) : Bits(RHS.Bits), Size(RHS.Size) {
159  RHS.Bits = MutableArrayRef<BitWord>();
160  RHS.Size = 0;
161  }
162 
163  ~BitVector() { std::free(Bits.data()); }
164 
165  /// empty - Tests whether there are no bits in this bitvector.
166  bool empty() const { return Size == 0; }
167 
168  /// size - Returns the number of bits in this bitvector.
169  size_type size() const { return Size; }
170 
171  /// count - Returns the number of bits which are set.
172  size_type count() const {
173  unsigned NumBits = 0;
174  for (unsigned i = 0; i < NumBitWords(size()); ++i)
175  NumBits += countPopulation(Bits[i]);
176  return NumBits;
177  }
178 
179  /// any - Returns true if any bit is set.
180  bool any() const {
181  for (unsigned i = 0; i < NumBitWords(size()); ++i)
182  if (Bits[i] != 0)
183  return true;
184  return false;
185  }
186 
187  /// all - Returns true if all bits are set.
188  bool all() const {
189  for (unsigned i = 0; i < Size / BITWORD_SIZE; ++i)
190  if (Bits[i] != ~0UL)
191  return false;
192 
193  // If bits remain check that they are ones. The unused bits are always zero.
194  if (unsigned Remainder = Size % BITWORD_SIZE)
195  return Bits[Size / BITWORD_SIZE] == (1UL << Remainder) - 1;
196 
197  return true;
198  }
199 
200  /// none - Returns true if none of the bits are set.
201  bool none() const {
202  return !any();
203  }
204 
205  /// find_first_in - Returns the index of the first set bit in the range
206  /// [Begin, End). Returns -1 if all bits in the range are unset.
207  int find_first_in(unsigned Begin, unsigned End) const {
208  assert(Begin <= End && End <= Size);
209  if (Begin == End)
210  return -1;
211 
212  unsigned FirstWord = Begin / BITWORD_SIZE;
213  unsigned LastWord = (End - 1) / BITWORD_SIZE;
214 
215  // Check subsequent words.
216  for (unsigned i = FirstWord; i <= LastWord; ++i) {
217  BitWord Copy = Bits[i];
218 
219  if (i == FirstWord) {
220  unsigned FirstBit = Begin % BITWORD_SIZE;
221  Copy &= maskTrailingZeros<BitWord>(FirstBit);
222  }
223 
224  if (i == LastWord) {
225  unsigned LastBit = (End - 1) % BITWORD_SIZE;
226  Copy &= maskTrailingOnes<BitWord>(LastBit + 1);
227  }
228  if (Copy != 0)
229  return i * BITWORD_SIZE + countTrailingZeros(Copy);
230  }
231  return -1;
232  }
233 
234  /// find_last_in - Returns the index of the last set bit in the range
235  /// [Begin, End). Returns -1 if all bits in the range are unset.
236  int find_last_in(unsigned Begin, unsigned End) const {
237  assert(Begin <= End && End <= Size);
238  if (Begin == End)
239  return -1;
240 
241  unsigned LastWord = (End - 1) / BITWORD_SIZE;
242  unsigned FirstWord = Begin / BITWORD_SIZE;
243 
244  for (unsigned i = LastWord + 1; i >= FirstWord + 1; --i) {
245  unsigned CurrentWord = i - 1;
246 
247  BitWord Copy = Bits[CurrentWord];
248  if (CurrentWord == LastWord) {
249  unsigned LastBit = (End - 1) % BITWORD_SIZE;
250  Copy &= maskTrailingOnes<BitWord>(LastBit + 1);
251  }
252 
253  if (CurrentWord == FirstWord) {
254  unsigned FirstBit = Begin % BITWORD_SIZE;
255  Copy &= maskTrailingZeros<BitWord>(FirstBit);
256  }
257 
258  if (Copy != 0)
259  return (CurrentWord + 1) * BITWORD_SIZE - countLeadingZeros(Copy) - 1;
260  }
261 
262  return -1;
263  }
264 
265  /// find_first_unset_in - Returns the index of the first unset bit in the
266  /// range [Begin, End). Returns -1 if all bits in the range are set.
267  int find_first_unset_in(unsigned Begin, unsigned End) const {
268  assert(Begin <= End && End <= Size);
269  if (Begin == End)
270  return -1;
271 
272  unsigned FirstWord = Begin / BITWORD_SIZE;
273  unsigned LastWord = (End - 1) / BITWORD_SIZE;
274 
275  // Check subsequent words.
276  for (unsigned i = FirstWord; i <= LastWord; ++i) {
277  BitWord Copy = Bits[i];
278 
279  if (i == FirstWord) {
280  unsigned FirstBit = Begin % BITWORD_SIZE;
281  Copy |= maskTrailingOnes<BitWord>(FirstBit);
282  }
283 
284  if (i == LastWord) {
285  unsigned LastBit = (End - 1) % BITWORD_SIZE;
286  Copy |= maskTrailingZeros<BitWord>(LastBit + 1);
287  }
288  if (Copy != ~0UL) {
289  unsigned Result = i * BITWORD_SIZE + countTrailingOnes(Copy);
290  return Result < size() ? Result : -1;
291  }
292  }
293  return -1;
294  }
295 
296  /// find_last_unset_in - Returns the index of the last unset bit in the
297  /// range [Begin, End). Returns -1 if all bits in the range are set.
298  int find_last_unset_in(unsigned Begin, unsigned End) const {
299  assert(Begin <= End && End <= Size);
300  if (Begin == End)
301  return -1;
302 
303  unsigned LastWord = (End - 1) / BITWORD_SIZE;
304  unsigned FirstWord = Begin / BITWORD_SIZE;
305 
306  for (unsigned i = LastWord + 1; i >= FirstWord + 1; --i) {
307  unsigned CurrentWord = i - 1;
308 
309  BitWord Copy = Bits[CurrentWord];
310  if (CurrentWord == LastWord) {
311  unsigned LastBit = (End - 1) % BITWORD_SIZE;
312  Copy |= maskTrailingZeros<BitWord>(LastBit + 1);
313  }
314 
315  if (CurrentWord == FirstWord) {
316  unsigned FirstBit = Begin % BITWORD_SIZE;
317  Copy |= maskTrailingOnes<BitWord>(FirstBit);
318  }
319 
320  if (Copy != ~0UL) {
321  unsigned Result =
322  (CurrentWord + 1) * BITWORD_SIZE - countLeadingOnes(Copy) - 1;
323  return Result < Size ? Result : -1;
324  }
325  }
326  return -1;
327  }
328 
329  /// find_first - Returns the index of the first set bit, -1 if none
330  /// of the bits are set.
331  int find_first() const { return find_first_in(0, Size); }
332 
333  /// find_last - Returns the index of the last set bit, -1 if none of the bits
334  /// are set.
335  int find_last() const { return find_last_in(0, Size); }
336 
337  /// find_next - Returns the index of the next set bit following the
338  /// "Prev" bit. Returns -1 if the next set bit is not found.
339  int find_next(unsigned Prev) const { return find_first_in(Prev + 1, Size); }
340 
341  /// find_prev - Returns the index of the first set bit that precedes the
342  /// the bit at \p PriorTo. Returns -1 if all previous bits are unset.
343  int find_prev(unsigned PriorTo) const { return find_last_in(0, PriorTo); }
344 
345  /// find_first_unset - Returns the index of the first unset bit, -1 if all
346  /// of the bits are set.
347  int find_first_unset() const { return find_first_unset_in(0, Size); }
348 
349  /// find_next_unset - Returns the index of the next unset bit following the
350  /// "Prev" bit. Returns -1 if all remaining bits are set.
351  int find_next_unset(unsigned Prev) const {
352  return find_first_unset_in(Prev + 1, Size);
353  }
354 
355  /// find_last_unset - Returns the index of the last unset bit, -1 if all of
356  /// the bits are set.
357  int find_last_unset() const { return find_last_unset_in(0, Size); }
358 
359  /// find_prev_unset - Returns the index of the first unset bit that precedes
360  /// the bit at \p PriorTo. Returns -1 if all previous bits are set.
361  int find_prev_unset(unsigned PriorTo) {
362  return find_last_unset_in(0, PriorTo);
363  }
364 
365  /// clear - Removes all bits from the bitvector. Does not change capacity.
366  void clear() {
367  Size = 0;
368  }
369 
370  /// resize - Grow or shrink the bitvector.
371  void resize(unsigned N, bool t = false) {
372  if (N > getBitCapacity()) {
373  unsigned OldCapacity = Bits.size();
374  grow(N);
375  init_words(Bits.drop_front(OldCapacity), t);
376  }
377 
378  // Set any old unused bits that are now included in the BitVector. This
379  // may set bits that are not included in the new vector, but we will clear
380  // them back out below.
381  if (N > Size)
382  set_unused_bits(t);
383 
384  // Update the size, and clear out any bits that are now unused
385  unsigned OldSize = Size;
386  Size = N;
387  if (t || N < OldSize)
388  clear_unused_bits();
389  }
390 
391  void reserve(unsigned N) {
392  if (N > getBitCapacity())
393  grow(N);
394  }
395 
396  // Set, reset, flip
397  BitVector &set() {
398  init_words(Bits, true);
399  clear_unused_bits();
400  return *this;
401  }
402 
403  BitVector &set(unsigned Idx) {
404  assert(Bits.data() && "Bits never allocated");
405  Bits[Idx / BITWORD_SIZE] |= BitWord(1) << (Idx % BITWORD_SIZE);
406  return *this;
407  }
408 
409  /// set - Efficiently set a range of bits in [I, E)
410  BitVector &set(unsigned I, unsigned E) {
411  assert(I <= E && "Attempted to set backwards range!");
412  assert(E <= size() && "Attempted to set out-of-bounds range!");
413 
414  if (I == E) return *this;
415 
416  if (I / BITWORD_SIZE == E / BITWORD_SIZE) {
417  BitWord EMask = 1UL << (E % BITWORD_SIZE);
418  BitWord IMask = 1UL << (I % BITWORD_SIZE);
419  BitWord Mask = EMask - IMask;
420  Bits[I / BITWORD_SIZE] |= Mask;
421  return *this;
422  }
423 
424  BitWord PrefixMask = ~0UL << (I % BITWORD_SIZE);
425  Bits[I / BITWORD_SIZE] |= PrefixMask;
426  I = alignTo(I, BITWORD_SIZE);
427 
428  for (; I + BITWORD_SIZE <= E; I += BITWORD_SIZE)
429  Bits[I / BITWORD_SIZE] = ~0UL;
430 
431  BitWord PostfixMask = (1UL << (E % BITWORD_SIZE)) - 1;
432  if (I < E)
433  Bits[I / BITWORD_SIZE] |= PostfixMask;
434 
435  return *this;
436  }
437 
439  init_words(Bits, false);
440  return *this;
441  }
442 
443  BitVector &reset(unsigned Idx) {
444  Bits[Idx / BITWORD_SIZE] &= ~(BitWord(1) << (Idx % BITWORD_SIZE));
445  return *this;
446  }
447 
448  /// reset - Efficiently reset a range of bits in [I, E)
449  BitVector &reset(unsigned I, unsigned E) {
450  assert(I <= E && "Attempted to reset backwards range!");
451  assert(E <= size() && "Attempted to reset out-of-bounds range!");
452 
453  if (I == E) return *this;
454 
455  if (I / BITWORD_SIZE == E / BITWORD_SIZE) {
456  BitWord EMask = 1UL << (E % BITWORD_SIZE);
457  BitWord IMask = 1UL << (I % BITWORD_SIZE);
458  BitWord Mask = EMask - IMask;
459  Bits[I / BITWORD_SIZE] &= ~Mask;
460  return *this;
461  }
462 
463  BitWord PrefixMask = ~0UL << (I % BITWORD_SIZE);
464  Bits[I / BITWORD_SIZE] &= ~PrefixMask;
465  I = alignTo(I, BITWORD_SIZE);
466 
467  for (; I + BITWORD_SIZE <= E; I += BITWORD_SIZE)
468  Bits[I / BITWORD_SIZE] = 0UL;
469 
470  BitWord PostfixMask = (1UL << (E % BITWORD_SIZE)) - 1;
471  if (I < E)
472  Bits[I / BITWORD_SIZE] &= ~PostfixMask;
473 
474  return *this;
475  }
476 
478  for (unsigned i = 0; i < NumBitWords(size()); ++i)
479  Bits[i] = ~Bits[i];
480  clear_unused_bits();
481  return *this;
482  }
483 
484  BitVector &flip(unsigned Idx) {
485  Bits[Idx / BITWORD_SIZE] ^= BitWord(1) << (Idx % BITWORD_SIZE);
486  return *this;
487  }
488 
489  // Indexing.
490  reference operator[](unsigned Idx) {
491  assert (Idx < Size && "Out-of-bounds Bit access.");
492  return reference(*this, Idx);
493  }
494 
495  bool operator[](unsigned Idx) const {
496  assert (Idx < Size && "Out-of-bounds Bit access.");
497  BitWord Mask = BitWord(1) << (Idx % BITWORD_SIZE);
498  return (Bits[Idx / BITWORD_SIZE] & Mask) != 0;
499  }
500 
501  bool test(unsigned Idx) const {
502  return (*this)[Idx];
503  }
504 
505  // Push single bit to end of vector.
506  void push_back(bool Val) {
507  unsigned OldSize = Size;
508  unsigned NewSize = Size + 1;
509 
510  // Resize, which will insert zeros.
511  // If we already fit then the unused bits will be already zero.
512  if (NewSize > getBitCapacity())
513  resize(NewSize, false);
514  else
515  Size = NewSize;
516 
517  // If true, set single bit.
518  if (Val)
519  set(OldSize);
520  }
521 
522  /// Test if any common bits are set.
523  bool anyCommon(const BitVector &RHS) const {
524  unsigned ThisWords = NumBitWords(size());
525  unsigned RHSWords = NumBitWords(RHS.size());
526  for (unsigned i = 0, e = std::min(ThisWords, RHSWords); i != e; ++i)
527  if (Bits[i] & RHS.Bits[i])
528  return true;
529  return false;
530  }
531 
532  // Comparison operators.
533  bool operator==(const BitVector &RHS) const {
534  unsigned ThisWords = NumBitWords(size());
535  unsigned RHSWords = NumBitWords(RHS.size());
536  unsigned i;
537  for (i = 0; i != std::min(ThisWords, RHSWords); ++i)
538  if (Bits[i] != RHS.Bits[i])
539  return false;
540 
541  // Verify that any extra words are all zeros.
542  if (i != ThisWords) {
543  for (; i != ThisWords; ++i)
544  if (Bits[i])
545  return false;
546  } else if (i != RHSWords) {
547  for (; i != RHSWords; ++i)
548  if (RHS.Bits[i])
549  return false;
550  }
551  return true;
552  }
553 
554  bool operator!=(const BitVector &RHS) const {
555  return !(*this == RHS);
556  }
557 
558  /// Intersection, union, disjoint union.
560  unsigned ThisWords = NumBitWords(size());
561  unsigned RHSWords = NumBitWords(RHS.size());
562  unsigned i;
563  for (i = 0; i != std::min(ThisWords, RHSWords); ++i)
564  Bits[i] &= RHS.Bits[i];
565 
566  // Any bits that are just in this bitvector become zero, because they aren't
567  // in the RHS bit vector. Any words only in RHS are ignored because they
568  // are already zero in the LHS.
569  for (; i != ThisWords; ++i)
570  Bits[i] = 0;
571 
572  return *this;
573  }
574 
575  /// reset - Reset bits that are set in RHS. Same as *this &= ~RHS.
576  BitVector &reset(const BitVector &RHS) {
577  unsigned ThisWords = NumBitWords(size());
578  unsigned RHSWords = NumBitWords(RHS.size());
579  unsigned i;
580  for (i = 0; i != std::min(ThisWords, RHSWords); ++i)
581  Bits[i] &= ~RHS.Bits[i];
582  return *this;
583  }
584 
585  /// test - Check if (This - RHS) is zero.
586  /// This is the same as reset(RHS) and any().
587  bool test(const BitVector &RHS) const {
588  unsigned ThisWords = NumBitWords(size());
589  unsigned RHSWords = NumBitWords(RHS.size());
590  unsigned i;
591  for (i = 0; i != std::min(ThisWords, RHSWords); ++i)
592  if ((Bits[i] & ~RHS.Bits[i]) != 0)
593  return true;
594 
595  for (; i != ThisWords ; ++i)
596  if (Bits[i] != 0)
597  return true;
598 
599  return false;
600  }
601 
603  if (size() < RHS.size())
604  resize(RHS.size());
605  for (size_t i = 0, e = NumBitWords(RHS.size()); i != e; ++i)
606  Bits[i] |= RHS.Bits[i];
607  return *this;
608  }
609 
611  if (size() < RHS.size())
612  resize(RHS.size());
613  for (size_t i = 0, e = NumBitWords(RHS.size()); i != e; ++i)
614  Bits[i] ^= RHS.Bits[i];
615  return *this;
616  }
617 
618  BitVector &operator>>=(unsigned N) {
619  assert(N <= Size);
620  if (LLVM_UNLIKELY(empty() || N == 0))
621  return *this;
622 
623  unsigned NumWords = NumBitWords(Size);
624  assert(NumWords >= 1);
625 
626  wordShr(N / BITWORD_SIZE);
627 
628  unsigned BitDistance = N % BITWORD_SIZE;
629  if (BitDistance == 0)
630  return *this;
631 
632  // When the shift size is not a multiple of the word size, then we have
633  // a tricky situation where each word in succession needs to extract some
634  // of the bits from the next word and or them into this word while
635  // shifting this word to make room for the new bits. This has to be done
636  // for every word in the array.
637 
638  // Since we're shifting each word right, some bits will fall off the end
639  // of each word to the right, and empty space will be created on the left.
640  // The final word in the array will lose bits permanently, so starting at
641  // the beginning, work forwards shifting each word to the right, and
642  // OR'ing in the bits from the end of the next word to the beginning of
643  // the current word.
644 
645  // Example:
646  // Starting with {0xAABBCCDD, 0xEEFF0011, 0x22334455} and shifting right
647  // by 4 bits.
648  // Step 1: Word[0] >>= 4 ; 0x0ABBCCDD
649  // Step 2: Word[0] |= 0x10000000 ; 0x1ABBCCDD
650  // Step 3: Word[1] >>= 4 ; 0x0EEFF001
651  // Step 4: Word[1] |= 0x50000000 ; 0x5EEFF001
652  // Step 5: Word[2] >>= 4 ; 0x02334455
653  // Result: { 0x1ABBCCDD, 0x5EEFF001, 0x02334455 }
654  const BitWord Mask = maskTrailingOnes<BitWord>(BitDistance);
655  const unsigned LSH = BITWORD_SIZE - BitDistance;
656 
657  for (unsigned I = 0; I < NumWords - 1; ++I) {
658  Bits[I] >>= BitDistance;
659  Bits[I] |= (Bits[I + 1] & Mask) << LSH;
660  }
661 
662  Bits[NumWords - 1] >>= BitDistance;
663 
664  return *this;
665  }
666 
667  BitVector &operator<<=(unsigned N) {
668  assert(N <= Size);
669  if (LLVM_UNLIKELY(empty() || N == 0))
670  return *this;
671 
672  unsigned NumWords = NumBitWords(Size);
673  assert(NumWords >= 1);
674 
675  wordShl(N / BITWORD_SIZE);
676 
677  unsigned BitDistance = N % BITWORD_SIZE;
678  if (BitDistance == 0)
679  return *this;
680 
681  // When the shift size is not a multiple of the word size, then we have
682  // a tricky situation where each word in succession needs to extract some
683  // of the bits from the previous word and or them into this word while
684  // shifting this word to make room for the new bits. This has to be done
685  // for every word in the array. This is similar to the algorithm outlined
686  // in operator>>=, but backwards.
687 
688  // Since we're shifting each word left, some bits will fall off the end
689  // of each word to the left, and empty space will be created on the right.
690  // The first word in the array will lose bits permanently, so starting at
691  // the end, work backwards shifting each word to the left, and OR'ing
692  // in the bits from the end of the next word to the beginning of the
693  // current word.
694 
695  // Example:
696  // Starting with {0xAABBCCDD, 0xEEFF0011, 0x22334455} and shifting left
697  // by 4 bits.
698  // Step 1: Word[2] <<= 4 ; 0x23344550
699  // Step 2: Word[2] |= 0x0000000E ; 0x2334455E
700  // Step 3: Word[1] <<= 4 ; 0xEFF00110
701  // Step 4: Word[1] |= 0x0000000A ; 0xEFF0011A
702  // Step 5: Word[0] <<= 4 ; 0xABBCCDD0
703  // Result: { 0xABBCCDD0, 0xEFF0011A, 0x2334455E }
704  const BitWord Mask = maskLeadingOnes<BitWord>(BitDistance);
705  const unsigned RSH = BITWORD_SIZE - BitDistance;
706 
707  for (int I = NumWords - 1; I > 0; --I) {
708  Bits[I] <<= BitDistance;
709  Bits[I] |= (Bits[I - 1] & Mask) >> RSH;
710  }
711  Bits[0] <<= BitDistance;
712  clear_unused_bits();
713 
714  return *this;
715  }
716 
717  // Assignment operator.
718  const BitVector &operator=(const BitVector &RHS) {
719  if (this == &RHS) return *this;
720 
721  Size = RHS.size();
722  unsigned RHSWords = NumBitWords(Size);
723  if (Size <= getBitCapacity()) {
724  if (Size)
725  std::memcpy(Bits.data(), RHS.Bits.data(), RHSWords * sizeof(BitWord));
726  clear_unused_bits();
727  return *this;
728  }
729 
730  // Grow the bitvector to have enough elements.
731  unsigned NewCapacity = RHSWords;
732  assert(NewCapacity > 0 && "negative capacity?");
733  auto NewBits = allocate(NewCapacity);
734  std::memcpy(NewBits.data(), RHS.Bits.data(), NewCapacity * sizeof(BitWord));
735 
736  // Destroy the old bits.
737  std::free(Bits.data());
738  Bits = NewBits;
739 
740  return *this;
741  }
742 
743  const BitVector &operator=(BitVector &&RHS) {
744  if (this == &RHS) return *this;
745 
746  std::free(Bits.data());
747  Bits = RHS.Bits;
748  Size = RHS.Size;
749 
750  RHS.Bits = MutableArrayRef<BitWord>();
751  RHS.Size = 0;
752 
753  return *this;
754  }
755 
756  void swap(BitVector &RHS) {
757  std::swap(Bits, RHS.Bits);
758  std::swap(Size, RHS.Size);
759  }
760 
761  //===--------------------------------------------------------------------===//
762  // Portable bit mask operations.
763  //===--------------------------------------------------------------------===//
764  //
765  // These methods all operate on arrays of uint32_t, each holding 32 bits. The
766  // fixed word size makes it easier to work with literal bit vector constants
767  // in portable code.
768  //
769  // The LSB in each word is the lowest numbered bit. The size of a portable
770  // bit mask is always a whole multiple of 32 bits. If no bit mask size is
771  // given, the bit mask is assumed to cover the entire BitVector.
772 
773  /// setBitsInMask - Add '1' bits from Mask to this vector. Don't resize.
774  /// This computes "*this |= Mask".
775  void setBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
776  applyMask<true, false>(Mask, MaskWords);
777  }
778 
779  /// clearBitsInMask - Clear any bits in this vector that are set in Mask.
780  /// Don't resize. This computes "*this &= ~Mask".
781  void clearBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
782  applyMask<false, false>(Mask, MaskWords);
783  }
784 
785  /// setBitsNotInMask - Add a bit to this vector for every '0' bit in Mask.
786  /// Don't resize. This computes "*this |= ~Mask".
787  void setBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
788  applyMask<true, true>(Mask, MaskWords);
789  }
790 
791  /// clearBitsNotInMask - Clear a bit in this vector for every '0' bit in Mask.
792  /// Don't resize. This computes "*this &= Mask".
793  void clearBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
794  applyMask<false, true>(Mask, MaskWords);
795  }
796 
797 private:
798  /// Perform a logical left shift of \p Count words by moving everything
799  /// \p Count words to the right in memory.
800  ///
801  /// While confusing, words are stored from least significant at Bits[0] to
802  /// most significant at Bits[NumWords-1]. A logical shift left, however,
803  /// moves the current least significant bit to a higher logical index, and
804  /// fills the previous least significant bits with 0. Thus, we actually
805  /// need to move the bytes of the memory to the right, not to the left.
806  /// Example:
807  /// Words = [0xBBBBAAAA, 0xDDDDFFFF, 0x00000000, 0xDDDD0000]
808  /// represents a BitVector where 0xBBBBAAAA contain the least significant
809  /// bits. So if we want to shift the BitVector left by 2 words, we need to
810  /// turn this into 0x00000000 0x00000000 0xBBBBAAAA 0xDDDDFFFF by using a
811  /// memmove which moves right, not left.
812  void wordShl(uint32_t Count) {
813  if (Count == 0)
814  return;
815 
816  uint32_t NumWords = NumBitWords(Size);
817 
818  auto Src = Bits.take_front(NumWords).drop_back(Count);
819  auto Dest = Bits.take_front(NumWords).drop_front(Count);
820 
821  // Since we always move Word-sized chunks of data with src and dest both
822  // aligned to a word-boundary, we don't need to worry about endianness
823  // here.
824  std::memmove(Dest.begin(), Src.begin(), Dest.size() * sizeof(BitWord));
825  std::memset(Bits.data(), 0, Count * sizeof(BitWord));
826  clear_unused_bits();
827  }
828 
829  /// Perform a logical right shift of \p Count words by moving those
830  /// words to the left in memory. See wordShl for more information.
831  ///
832  void wordShr(uint32_t Count) {
833  if (Count == 0)
834  return;
835 
836  uint32_t NumWords = NumBitWords(Size);
837 
838  auto Src = Bits.take_front(NumWords).drop_front(Count);
839  auto Dest = Bits.take_front(NumWords).drop_back(Count);
840  assert(Dest.size() == Src.size());
841 
842  std::memmove(Dest.begin(), Src.begin(), Dest.size() * sizeof(BitWord));
843  std::memset(Dest.end(), 0, Count * sizeof(BitWord));
844  }
845 
846  MutableArrayRef<BitWord> allocate(size_t NumWords) {
847  BitWord *RawBits = static_cast<BitWord *>(
848  safe_malloc(NumWords * sizeof(BitWord)));
849  return MutableArrayRef<BitWord>(RawBits, NumWords);
850  }
851 
852  int next_unset_in_word(int WordIndex, BitWord Word) const {
853  unsigned Result = WordIndex * BITWORD_SIZE + countTrailingOnes(Word);
854  return Result < size() ? Result : -1;
855  }
856 
857  unsigned NumBitWords(unsigned S) const {
858  return (S + BITWORD_SIZE-1) / BITWORD_SIZE;
859  }
860 
861  // Set the unused bits in the high words.
862  void set_unused_bits(bool t = true) {
863  // Set high words first.
864  unsigned UsedWords = NumBitWords(Size);
865  if (Bits.size() > UsedWords)
866  init_words(Bits.drop_front(UsedWords), t);
867 
868  // Then set any stray high bits of the last used word.
869  unsigned ExtraBits = Size % BITWORD_SIZE;
870  if (ExtraBits) {
871  BitWord ExtraBitMask = ~0UL << ExtraBits;
872  if (t)
873  Bits[UsedWords-1] |= ExtraBitMask;
874  else
875  Bits[UsedWords-1] &= ~ExtraBitMask;
876  }
877  }
878 
879  // Clear the unused bits in the high words.
880  void clear_unused_bits() {
881  set_unused_bits(false);
882  }
883 
884  void grow(unsigned NewSize) {
885  size_t NewCapacity = std::max<size_t>(NumBitWords(NewSize), Bits.size() * 2);
886  assert(NewCapacity > 0 && "realloc-ing zero space");
887  BitWord *NewBits = static_cast<BitWord *>(
888  safe_realloc(Bits.data(), NewCapacity * sizeof(BitWord)));
889  Bits = MutableArrayRef<BitWord>(NewBits, NewCapacity);
890  clear_unused_bits();
891  }
892 
893  void init_words(MutableArrayRef<BitWord> B, bool t) {
894  if (B.size() > 0)
895  memset(B.data(), 0 - (int)t, B.size() * sizeof(BitWord));
896  }
897 
898  template<bool AddBits, bool InvertMask>
899  void applyMask(const uint32_t *Mask, unsigned MaskWords) {
900  static_assert(BITWORD_SIZE % 32 == 0, "Unsupported BitWord size.");
901  MaskWords = std::min(MaskWords, (size() + 31) / 32);
902  const unsigned Scale = BITWORD_SIZE / 32;
903  unsigned i;
904  for (i = 0; MaskWords >= Scale; ++i, MaskWords -= Scale) {
905  BitWord BW = Bits[i];
906  // This inner loop should unroll completely when BITWORD_SIZE > 32.
907  for (unsigned b = 0; b != BITWORD_SIZE; b += 32) {
908  uint32_t M = *Mask++;
909  if (InvertMask) M = ~M;
910  if (AddBits) BW |= BitWord(M) << b;
911  else BW &= ~(BitWord(M) << b);
912  }
913  Bits[i] = BW;
914  }
915  for (unsigned b = 0; MaskWords; b += 32, --MaskWords) {
916  uint32_t M = *Mask++;
917  if (InvertMask) M = ~M;
918  if (AddBits) Bits[i] |= BitWord(M) << b;
919  else Bits[i] &= ~(BitWord(M) << b);
920  }
921  if (AddBits)
922  clear_unused_bits();
923  }
924 
925 public:
926  /// Return the size (in bytes) of the bit vector.
927  size_t getMemorySize() const { return Bits.size() * sizeof(BitWord); }
928  size_t getBitCapacity() const { return Bits.size() * BITWORD_SIZE; }
929 };
930 
931 inline size_t capacity_in_bytes(const BitVector &X) {
932  return X.getMemorySize();
933 }
934 
935 } // end namespace llvm
936 
937 namespace std {
938  /// Implement std::swap in terms of BitVector swap.
939  inline void
941  LHS.swap(RHS);
942  }
943 } // end namespace std
944 
945 #endif // LLVM_ADT_BITVECTOR_H
BitVector & reset(const BitVector &RHS)
reset - Reset bits that are set in RHS. Same as *this &= ~RHS.
Definition: BitVector.h:576
void resize(unsigned N, bool t=false)
resize - Grow or shrink the bitvector.
Definition: BitVector.h:371
void clearBitsInMask(const uint32_t *Mask, unsigned MaskWords=~0u)
clearBitsInMask - Clear any bits in this vector that are set in Mask.
Definition: BitVector.h:781
void reserve(unsigned N)
Definition: BitVector.h:391
static GCMetadataPrinterRegistry::Add< ErlangGCPrinter > X("erlang", "erlang-compatible garbage collector")
int find_last_unset() const
find_last_unset - Returns the index of the last unset bit, -1 if all of the bits are set...
Definition: BitVector.h:357
This class represents lattice values for constants.
Definition: AllocatorList.h:23
bool empty() const
empty - Tests whether there are no bits in this bitvector.
Definition: BitVector.h:166
const_set_bits_iterator set_bits_end() const
Definition: BitVector.h:126
#define LLVM_UNLIKELY(EXPR)
Definition: Compiler.h:199
int find_last() const
find_last - Returns the index of the last set bit, -1 if none of the bits are set.
Definition: BitVector.h:335
unsigned countLeadingOnes(T Value, ZeroBehavior ZB=ZB_Width)
Count the number of ones from the most significant bit to the first zero bit.
Definition: MathExtras.h:461
This provides a very simple, boring adaptor for a begin and end iterator into a range type...
unsigned size_type
Definition: BitVector.h:85
bool all() const
all - Returns true if all bits are set.
Definition: BitVector.h:188
bool test(unsigned Idx) const
Definition: BitVector.h:501
const_set_bits_iterator_impl operator++(int)
Definition: BitVector.h:47
BitVector(const BitVector &RHS)
BitVector copy ctor.
Definition: BitVector.h:147
void setBitsNotInMask(const uint32_t *Mask, unsigned MaskWords=~0u)
setBitsNotInMask - Add a bit to this vector for every &#39;0&#39; bit in Mask.
Definition: BitVector.h:787
bool operator[](unsigned Idx) const
Definition: BitVector.h:495
int find_next_unset(unsigned Prev) const
find_next_unset - Returns the index of the next unset bit following the "Prev" bit.
Definition: BitVector.h:351
BitVector & operator>>=(unsigned N)
Definition: BitVector.h:618
unsigned countTrailingZeros(T Val, ZeroBehavior ZB=ZB_Width)
Count number of 0&#39;s from the least significant bit to the most stopping at the first 1...
Definition: MathExtras.h:119
Definition: BitVector.h:937
BitVector & operator<<=(unsigned N)
Definition: BitVector.h:667
void clear()
clear - Removes all bits from the bitvector. Does not change capacity.
Definition: BitVector.h:366
size_t getMemorySize() const
Return the size (in bytes) of the bit vector.
Definition: BitVector.h:927
int find_prev_unset(unsigned PriorTo)
find_prev_unset - Returns the index of the first unset bit that precedes the bit at PriorTo...
Definition: BitVector.h:361
bool operator==(const const_set_bits_iterator_impl &Other) const
Definition: BitVector.h:60
int find_first() const
find_first - Returns the index of the first set bit, -1 if none of the bits are set.
Definition: BitVector.h:331
size_t capacity_in_bytes(const BitVector &X)
Definition: BitVector.h:931
support::ulittle32_t Word
Definition: IRSymtab.h:50
void swap(BitVector &RHS)
Definition: BitVector.h:756
int find_next(unsigned Prev) const
find_next - Returns the index of the next set bit following the "Prev" bit.
Definition: BitVector.h:339
reference(BitVector &b, unsigned Idx)
Definition: BitVector.h:94
const_set_bits_iterator_impl(const BitVectorT &Parent, int Current)
Definition: BitVector.h:41
MutableArrayRef< T > drop_front(size_t N=1) const
Drop the first N elements of the array.
Definition: ArrayRef.h:361
BitVector & operator|=(const BitVector &RHS)
Definition: BitVector.h:602
int find_first_unset() const
find_first_unset - Returns the index of the first unset bit, -1 if all of the bits are set...
Definition: BitVector.h:347
LLVM_ATTRIBUTE_RETURNS_NONNULL void * safe_realloc(void *Ptr, size_t Sz)
Definition: MemAlloc.h:52
int find_first_unset_in(unsigned Begin, unsigned End) const
find_first_unset_in - Returns the index of the first unset bit in the range [Begin, End).
Definition: BitVector.h:267
BitVector()
BitVector default ctor - Creates an empty bitvector.
Definition: BitVector.h:134
BitVector & flip(unsigned Idx)
Definition: BitVector.h:484
const_set_bits_iterator_impl & operator++()
Definition: BitVector.h:53
void clearBitsNotInMask(const uint32_t *Mask, unsigned MaskWords=~0u)
clearBitsNotInMask - Clear a bit in this vector for every &#39;0&#39; bit in Mask.
Definition: BitVector.h:793
static GCRegistry::Add< OcamlGC > B("ocaml", "ocaml 3.10-compatible GC")
bool anyCommon(const BitVector &RHS) const
Test if any common bits are set.
Definition: BitVector.h:523
int find_prev(unsigned PriorTo) const
find_prev - Returns the index of the first set bit that precedes the the bit at PriorTo.
Definition: BitVector.h:343
size_t getBitCapacity() const
Definition: BitVector.h:928
size_t size() const
size - Get the array size.
Definition: ArrayRef.h:148
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
bool any() const
any - Returns true if any bit is set.
Definition: BitVector.h:180
BitVector & operator^=(const BitVector &RHS)
Definition: BitVector.h:610
BitVector(unsigned s, bool t=false)
BitVector ctor - Creates a bitvector of specified number of bits.
Definition: BitVector.h:138
BitVector & reset()
Definition: BitVector.h:438
const_set_bits_iterator set_iterator
Definition: BitVector.h:121
const_set_bits_iterator set_bits_begin() const
Definition: BitVector.h:123
ForwardIterator for the bits that are set.
Definition: BitVector.h:31
BitVector(BitVector &&RHS)
Definition: BitVector.h:158
bool operator==(const BitVector &RHS) const
Definition: BitVector.h:533
BitVector & reset(unsigned I, unsigned E)
reset - Efficiently reset a range of bits in [I, E)
Definition: BitVector.h:449
unsigned countLeadingZeros(T Val, ZeroBehavior ZB=ZB_Width)
Count number of 0&#39;s from the most significant bit to the least stopping at the first 1...
Definition: MathExtras.h:188
MutableArrayRef< T > drop_back(size_t N=1) const
Definition: ArrayRef.h:366
void push_back(bool Val)
Definition: BitVector.h:506
constexpr bool empty(const T &RangeOrContainer)
Test whether RangeOrContainer is empty. Similar to C++17 std::empty.
Definition: STLExtras.h:209
const BitVector & operator=(const BitVector &RHS)
Definition: BitVector.h:718
iterator_range< T > make_range(T x, T y)
Convenience function for iterating over sub-ranges.
LLVM_ATTRIBUTE_RETURNS_NONNULL void * safe_malloc(size_t Sz)
Definition: MemAlloc.h:25
unsigned countPopulation(T Value)
Count the number of set bits in a value.
Definition: MathExtras.h:519
const_set_bits_iterator_impl(const BitVectorT &Parent)
Definition: BitVector.h:43
auto size(R &&Range, typename std::enable_if< std::is_same< typename std::iterator_traits< decltype(Range.begin())>::iterator_category, std::random_access_iterator_tag >::value, void >::type *=nullptr) -> decltype(std::distance(Range.begin(), Range.end()))
Get the size of a range.
Definition: STLExtras.h:1158
int find_last_in(unsigned Begin, unsigned End) const
find_last_in - Returns the index of the last set bit in the range [Begin, End).
Definition: BitVector.h:236
size_type count() const
count - Returns the number of bits which are set.
Definition: BitVector.h:172
reference operator[](unsigned Idx)
Definition: BitVector.h:490
BitVector & flip()
Definition: BitVector.h:477
void swap(llvm::BitVector &LHS, llvm::BitVector &RHS)
Implement std::swap in terms of BitVector swap.
Definition: BitVector.h:940
A range adaptor for a pair of iterators.
bool none() const
none - Returns true if none of the bits are set.
Definition: BitVector.h:201
uint64_t alignTo(uint64_t Size, Align A)
Returns a multiple of A needed to store Size bytes.
Definition: Alignment.h:126
MutableArrayRef< T > take_front(size_t N=1) const
Return a copy of *this with only the first N elements.
Definition: ArrayRef.h:386
reference & operator=(bool t)
Definition: BitVector.h:107
int find_first_in(unsigned Begin, unsigned End) const
find_first_in - Returns the index of the first set bit in the range [Begin, End). ...
Definition: BitVector.h:207
#define I(x, y, z)
Definition: MD5.cpp:58
#define N
reference & operator=(reference t)
Definition: BitVector.h:102
size_type size() const
size - Returns the number of bits in this bitvector.
Definition: BitVector.h:169
uint32_t Size
Definition: Profile.cpp:46
const_set_bits_iterator_impl< BitVector > const_set_bits_iterator
Definition: BitVector.h:120
T * data() const
Definition: ArrayRef.h:328
bool operator!=(const const_set_bits_iterator_impl &Other) const
Definition: BitVector.h:66
BitVector & reset(unsigned Idx)
Definition: BitVector.h:443
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
iterator_range< const_set_bits_iterator > set_bits() const
Definition: BitVector.h:129
E & operator &=(E &LHS, E RHS)
Definition: BitmaskEnum.h:133
unsigned countTrailingOnes(T Value, ZeroBehavior ZB=ZB_Width)
Count the number of ones from the least significant bit to the first zero bit.
Definition: MathExtras.h:477
std::underlying_type< E >::type Mask()
Get a bitmask with 1s in all places up to the high-order bit of E&#39;s largest value.
Definition: BitmaskEnum.h:80
bool test(const BitVector &RHS) const
test - Check if (This - RHS) is zero.
Definition: BitVector.h:587
int find_last_unset_in(unsigned Begin, unsigned End) const
find_last_unset_in - Returns the index of the last unset bit in the range [Begin, End)...
Definition: BitVector.h:298
for(unsigned i=Desc.getNumOperands(), e=OldMI.getNumOperands();i !=e;++i)
bool operator!=(const BitVector &RHS) const
Definition: BitVector.h:554
void setBitsInMask(const uint32_t *Mask, unsigned MaskWords=~0u)
setBitsInMask - Add &#39;1&#39; bits from Mask to this vector.
Definition: BitVector.h:775
const BitVector & operator=(BitVector &&RHS)
Definition: BitVector.h:743