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/// \file
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/ADT/ArrayRef.h"
18#include "llvm/ADT/DenseMapInfo.h"
19#include "llvm/ADT/iterator_range.h"
20#include "llvm/Support/MathExtras.h"
21#include <algorithm>
22#include <cassert>
23#include <climits>
24#include <cstdint>
25#include <cstdlib>
26#include <cstring>
27#include <iterator>
28#include <utility>
29
30namespace llvm {
31
32/// ForwardIterator for the bits that are set.
33/// Iterators get invalidated when resize / reserve is called.
34template <typename BitVectorT> class const_set_bits_iterator_impl {
35 const BitVectorT &Parent;
36 int Current = 0;
37
38 void advance() {
39 assert(Current != -1 && "Trying to advance past end.");
40 Current = Parent.find_next(Current);
41 }
42
43public:
44 using iterator_category = std::forward_iterator_tag;
45 using difference_type = void;
46 using value_type = int;
47 using pointer = value_type*;
48 using reference = value_type&;
49
50 const_set_bits_iterator_impl(const BitVectorT &Parent, int Current)
51 : Parent(Parent), Current(Current) {}
52 explicit const_set_bits_iterator_impl(const BitVectorT &Parent)
53 : const_set_bits_iterator_impl(Parent, Parent.find_first()) {}
54 const_set_bits_iterator_impl(const const_set_bits_iterator_impl &) = default;
55
56 const_set_bits_iterator_impl operator++(int) {
57 auto Prev = *this;
58 advance();
59 return Prev;
60 }
61
62 const_set_bits_iterator_impl &operator++() {
63 advance();
64 return *this;
65 }
66
67 unsigned operator*() const { return Current; }
68
69 bool operator==(const const_set_bits_iterator_impl &Other) const {
70 assert(&Parent == &Other.Parent &&
71 "Comparing iterators from different BitVectors");
72 return Current == Other.Current;
73 }
74
75 bool operator!=(const const_set_bits_iterator_impl &Other) const {
76 assert(&Parent == &Other.Parent &&
77 "Comparing iterators from different BitVectors");
78 return Current != Other.Current;
79 }
80};
81
82class BitVector {
83 typedef uintptr_t BitWord;
84
85 enum { BITWORD_SIZE = (unsigned)sizeof(BitWord) * CHAR_BIT };
86
87 static_assert(BITWORD_SIZE == 64 || BITWORD_SIZE == 32,
88 "Unsupported word size");
89
90 using Storage = SmallVector<BitWord>;
91
92 Storage Bits; // Actual bits.
93 unsigned Size = 0; // Size of bitvector in bits.
94
95public:
96 using size_type = unsigned;
97
98 // Encapsulation of a single bit.
99 class reference {
100
101 BitWord *WordRef;
102 unsigned BitPos;
103
104 public:
105 reference(BitVector &b, unsigned Idx) {
106 WordRef = &b.Bits[Idx / BITWORD_SIZE];
107 BitPos = Idx % BITWORD_SIZE;
108 }
109
110 reference() = delete;
111 reference(const reference&) = default;
112
113 reference &operator=(reference t) {
114 *this = bool(t);
115 return *this;
116 }
117
118 reference& operator=(bool t) {
119 if (t)
120 *WordRef |= BitWord(1) << BitPos;
121 else
122 *WordRef &= ~(BitWord(1) << BitPos);
123 return *this;
124 }
125
126 operator bool() const {
127 return ((*WordRef) & (BitWord(1) << BitPos)) != 0;
128 }
129 };
130
131 typedef const_set_bits_iterator_impl<BitVector> const_set_bits_iterator;
132 typedef const_set_bits_iterator set_iterator;
133
134 const_set_bits_iterator set_bits_begin() const {
135 return const_set_bits_iterator(*this);
136 }
137 const_set_bits_iterator set_bits_end() const {
138 return const_set_bits_iterator(*this, -1);
139 }
140 iterator_range<const_set_bits_iterator> set_bits() const {
141 return make_range(x: set_bits_begin(), y: set_bits_end());
142 }
143
144 /// BitVector default ctor - Creates an empty bitvector.
145 BitVector() = default;
146
147 /// BitVector ctor - Creates a bitvector of specified number of bits. All
148 /// bits are initialized to the specified value.
149 explicit BitVector(unsigned s, bool t = false)
150 : Bits(NumBitWords(S: s), 0 - (BitWord)t), Size(s) {
151 if (t)
152 clear_unused_bits();
153 }
154
155 /// empty - Tests whether there are no bits in this bitvector.
156 bool empty() const { return Size == 0; }
157
158 /// size - Returns the number of bits in this bitvector.
159 size_type size() const { return Size; }
160
161 /// count - Returns the number of bits which are set.
162 size_type count() const {
163 unsigned NumBits = 0;
164 for (auto Bit : Bits)
165 NumBits += llvm::popcount(Value: Bit);
166 return NumBits;
167 }
168
169 /// any - Returns true if any bit is set.
170 bool any() const {
171 return any_of(Range: Bits, P: [](BitWord Bit) { return Bit != 0; });
172 }
173
174 /// all - Returns true if all bits are set.
175 bool all() const {
176 for (unsigned i = 0; i < Size / BITWORD_SIZE; ++i)
177 if (Bits[i] != ~BitWord(0))
178 return false;
179
180 // If bits remain check that they are ones. The unused bits are always zero.
181 if (unsigned Remainder = Size % BITWORD_SIZE)
182 return Bits[Size / BITWORD_SIZE] == (BitWord(1) << Remainder) - 1;
183
184 return true;
185 }
186
187 /// none - Returns true if none of the bits are set.
188 bool none() const {
189 return !any();
190 }
191
192 /// find_first_in - Returns the index of the first set / unset bit,
193 /// depending on \p Set, in the range [Begin, End).
194 /// Returns -1 if all bits in the range are unset / set.
195 int find_first_in(unsigned Begin, unsigned End, bool Set = true) const {
196 assert(Begin <= End && End <= Size);
197 if (Begin == End)
198 return -1;
199
200 unsigned FirstWord = Begin / BITWORD_SIZE;
201 unsigned LastWord = (End - 1) / BITWORD_SIZE;
202
203 // Check subsequent words.
204 // The code below is based on search for the first _set_ bit. If
205 // we're searching for the first _unset_, we just take the
206 // complement of each word before we use it and apply
207 // the same method.
208 for (unsigned i = FirstWord; i <= LastWord; ++i) {
209 BitWord Copy = Bits[i];
210 if (!Set)
211 Copy = ~Copy;
212
213 if (i == FirstWord) {
214 unsigned FirstBit = Begin % BITWORD_SIZE;
215 Copy &= maskTrailingZeros<BitWord>(N: FirstBit);
216 }
217
218 if (i == LastWord) {
219 unsigned LastBit = (End - 1) % BITWORD_SIZE;
220 Copy &= maskTrailingOnes<BitWord>(N: LastBit + 1);
221 }
222 if (Copy != 0)
223 return i * BITWORD_SIZE + llvm::countr_zero(Val: Copy);
224 }
225 return -1;
226 }
227
228 /// find_last_in - Returns the index of the last set bit in the range
229 /// [Begin, End). Returns -1 if all bits in the range are unset.
230 int find_last_in(unsigned Begin, unsigned End) const {
231 assert(Begin <= End && End <= Size);
232 if (Begin == End)
233 return -1;
234
235 unsigned LastWord = (End - 1) / BITWORD_SIZE;
236 unsigned FirstWord = Begin / BITWORD_SIZE;
237
238 for (unsigned i = LastWord + 1; i >= FirstWord + 1; --i) {
239 unsigned CurrentWord = i - 1;
240
241 BitWord Copy = Bits[CurrentWord];
242 if (CurrentWord == LastWord) {
243 unsigned LastBit = (End - 1) % BITWORD_SIZE;
244 Copy &= maskTrailingOnes<BitWord>(N: LastBit + 1);
245 }
246
247 if (CurrentWord == FirstWord) {
248 unsigned FirstBit = Begin % BITWORD_SIZE;
249 Copy &= maskTrailingZeros<BitWord>(N: FirstBit);
250 }
251
252 if (Copy != 0)
253 return (CurrentWord + 1) * BITWORD_SIZE - llvm::countl_zero(Val: Copy) - 1;
254 }
255
256 return -1;
257 }
258
259 /// find_first_unset_in - Returns the index of the first unset bit in the
260 /// range [Begin, End). Returns -1 if all bits in the range are set.
261 int find_first_unset_in(unsigned Begin, unsigned End) const {
262 return find_first_in(Begin, End, /* Set = */ Set: false);
263 }
264
265 /// find_last_unset_in - Returns the index of the last unset bit in the
266 /// range [Begin, End). Returns -1 if all bits in the range are set.
267 int find_last_unset_in(unsigned Begin, unsigned End) const {
268 assert(Begin <= End && End <= Size);
269 if (Begin == End)
270 return -1;
271
272 unsigned LastWord = (End - 1) / BITWORD_SIZE;
273 unsigned FirstWord = Begin / BITWORD_SIZE;
274
275 for (unsigned i = LastWord + 1; i >= FirstWord + 1; --i) {
276 unsigned CurrentWord = i - 1;
277
278 BitWord Copy = Bits[CurrentWord];
279 if (CurrentWord == LastWord) {
280 unsigned LastBit = (End - 1) % BITWORD_SIZE;
281 Copy |= maskTrailingZeros<BitWord>(N: LastBit + 1);
282 }
283
284 if (CurrentWord == FirstWord) {
285 unsigned FirstBit = Begin % BITWORD_SIZE;
286 Copy |= maskTrailingOnes<BitWord>(N: FirstBit);
287 }
288
289 if (Copy != ~BitWord(0)) {
290 unsigned Result =
291 (CurrentWord + 1) * BITWORD_SIZE - llvm::countl_one(Value: Copy) - 1;
292 return Result < Size ? Result : -1;
293 }
294 }
295 return -1;
296 }
297
298 /// find_first - Returns the index of the first set bit, -1 if none
299 /// of the bits are set.
300 int find_first() const { return find_first_in(Begin: 0, End: Size); }
301
302 /// find_last - Returns the index of the last set bit, -1 if none of the bits
303 /// are set.
304 int find_last() const { return find_last_in(Begin: 0, End: Size); }
305
306 /// find_next - Returns the index of the next set bit following the
307 /// "Prev" bit. Returns -1 if the next set bit is not found.
308 int find_next(unsigned Prev) const { return find_first_in(Begin: Prev + 1, End: Size); }
309
310 /// find_prev - Returns the index of the first set bit that precedes the
311 /// the bit at \p PriorTo. Returns -1 if all previous bits are unset.
312 int find_prev(unsigned PriorTo) const { return find_last_in(Begin: 0, End: PriorTo); }
313
314 /// find_first_unset - Returns the index of the first unset bit, -1 if all
315 /// of the bits are set.
316 int find_first_unset() const { return find_first_unset_in(Begin: 0, End: Size); }
317
318 /// find_next_unset - Returns the index of the next unset bit following the
319 /// "Prev" bit. Returns -1 if all remaining bits are set.
320 int find_next_unset(unsigned Prev) const {
321 return find_first_unset_in(Begin: Prev + 1, End: Size);
322 }
323
324 /// find_last_unset - Returns the index of the last unset bit, -1 if all of
325 /// the bits are set.
326 int find_last_unset() const { return find_last_unset_in(Begin: 0, End: Size); }
327
328 /// find_prev_unset - Returns the index of the first unset bit that precedes
329 /// the bit at \p PriorTo. Returns -1 if all previous bits are set.
330 int find_prev_unset(unsigned PriorTo) {
331 return find_last_unset_in(Begin: 0, End: PriorTo);
332 }
333
334 /// clear - Removes all bits from the bitvector.
335 void clear() {
336 Size = 0;
337 Bits.clear();
338 }
339
340 /// resize - Grow or shrink the bitvector.
341 void resize(unsigned N, bool t = false) {
342 set_unused_bits(t);
343 Size = N;
344 Bits.resize(N: NumBitWords(S: N), NV: 0 - BitWord(t));
345 clear_unused_bits();
346 }
347
348 void reserve(unsigned N) { Bits.reserve(N: NumBitWords(S: N)); }
349
350 // Set, reset, flip
351 BitVector &set() {
352 init_words(t: true);
353 clear_unused_bits();
354 return *this;
355 }
356
357 BitVector &set(unsigned Idx) {
358 assert(Idx < Size && "access in bound");
359 Bits[Idx / BITWORD_SIZE] |= BitWord(1) << (Idx % BITWORD_SIZE);
360 return *this;
361 }
362
363 /// set - Efficiently set a range of bits in [I, E)
364 BitVector &set(unsigned I, unsigned E) {
365 assert(I <= E && "Attempted to set backwards range!");
366 assert(E <= size() && "Attempted to set out-of-bounds range!");
367
368 if (I == E) return *this;
369
370 if (I / BITWORD_SIZE == E / BITWORD_SIZE) {
371 BitWord EMask = BitWord(1) << (E % BITWORD_SIZE);
372 BitWord IMask = BitWord(1) << (I % BITWORD_SIZE);
373 BitWord Mask = EMask - IMask;
374 Bits[I / BITWORD_SIZE] |= Mask;
375 return *this;
376 }
377
378 BitWord PrefixMask = ~BitWord(0) << (I % BITWORD_SIZE);
379 Bits[I / BITWORD_SIZE] |= PrefixMask;
380 I = alignTo(Value: I, Align: BITWORD_SIZE);
381
382 for (; I + BITWORD_SIZE <= E; I += BITWORD_SIZE)
383 Bits[I / BITWORD_SIZE] = ~BitWord(0);
384
385 BitWord PostfixMask = (BitWord(1) << (E % BITWORD_SIZE)) - 1;
386 if (I < E)
387 Bits[I / BITWORD_SIZE] |= PostfixMask;
388
389 return *this;
390 }
391
392 BitVector &reset() {
393 init_words(t: false);
394 return *this;
395 }
396
397 BitVector &reset(unsigned Idx) {
398 Bits[Idx / BITWORD_SIZE] &= ~(BitWord(1) << (Idx % BITWORD_SIZE));
399 return *this;
400 }
401
402 /// reset - Efficiently reset a range of bits in [I, E)
403 BitVector &reset(unsigned I, unsigned E) {
404 assert(I <= E && "Attempted to reset backwards range!");
405 assert(E <= size() && "Attempted to reset out-of-bounds range!");
406
407 if (I == E) return *this;
408
409 if (I / BITWORD_SIZE == E / BITWORD_SIZE) {
410 BitWord EMask = BitWord(1) << (E % BITWORD_SIZE);
411 BitWord IMask = BitWord(1) << (I % BITWORD_SIZE);
412 BitWord Mask = EMask - IMask;
413 Bits[I / BITWORD_SIZE] &= ~Mask;
414 return *this;
415 }
416
417 BitWord PrefixMask = ~BitWord(0) << (I % BITWORD_SIZE);
418 Bits[I / BITWORD_SIZE] &= ~PrefixMask;
419 I = alignTo(Value: I, Align: BITWORD_SIZE);
420
421 for (; I + BITWORD_SIZE <= E; I += BITWORD_SIZE)
422 Bits[I / BITWORD_SIZE] = BitWord(0);
423
424 BitWord PostfixMask = (BitWord(1) << (E % BITWORD_SIZE)) - 1;
425 if (I < E)
426 Bits[I / BITWORD_SIZE] &= ~PostfixMask;
427
428 return *this;
429 }
430
431 BitVector &flip() {
432 for (auto &Bit : Bits)
433 Bit = ~Bit;
434 clear_unused_bits();
435 return *this;
436 }
437
438 BitVector &flip(unsigned Idx) {
439 Bits[Idx / BITWORD_SIZE] ^= BitWord(1) << (Idx % BITWORD_SIZE);
440 return *this;
441 }
442
443 // Indexing.
444 reference operator[](unsigned Idx) {
445 assert (Idx < Size && "Out-of-bounds Bit access.");
446 return reference(*this, Idx);
447 }
448
449 bool operator[](unsigned Idx) const {
450 assert (Idx < Size && "Out-of-bounds Bit access.");
451 BitWord Mask = BitWord(1) << (Idx % BITWORD_SIZE);
452 return (Bits[Idx / BITWORD_SIZE] & Mask) != 0;
453 }
454
455 /// Return the last element in the vector.
456 bool back() const {
457 assert(!empty() && "Getting last element of empty vector.");
458 return (*this)[size() - 1];
459 }
460
461 bool test(unsigned Idx) const {
462 return (*this)[Idx];
463 }
464
465 // Push single bit to end of vector.
466 void push_back(bool Val) {
467 unsigned OldSize = Size;
468 unsigned NewSize = Size + 1;
469
470 // Resize, which will insert zeros.
471 // If we already fit then the unused bits will be already zero.
472 if (NewSize > getBitCapacity())
473 resize(N: NewSize, t: false);
474 else
475 Size = NewSize;
476
477 // If true, set single bit.
478 if (Val)
479 set(OldSize);
480 }
481
482 /// Pop one bit from the end of the vector.
483 void pop_back() {
484 assert(!empty() && "Empty vector has no element to pop.");
485 resize(N: size() - 1);
486 }
487
488 /// Test if any common bits are set.
489 bool anyCommon(const BitVector &RHS) const {
490 unsigned ThisWords = Bits.size();
491 unsigned RHSWords = RHS.Bits.size();
492 for (unsigned i = 0, e = std::min(a: ThisWords, b: RHSWords); i != e; ++i)
493 if (Bits[i] & RHS.Bits[i])
494 return true;
495 return false;
496 }
497
498 // Comparison operators.
499 bool operator==(const BitVector &RHS) const {
500 if (size() != RHS.size())
501 return false;
502 unsigned NumWords = Bits.size();
503 return std::equal(first1: Bits.begin(), last1: Bits.begin() + NumWords, first2: RHS.Bits.begin());
504 }
505
506 bool operator!=(const BitVector &RHS) const { return !(*this == RHS); }
507
508 /// Intersection, union, disjoint union.
509 BitVector &operator&=(const BitVector &RHS) {
510 unsigned ThisWords = Bits.size();
511 unsigned RHSWords = RHS.Bits.size();
512 unsigned i;
513 for (i = 0; i != std::min(a: ThisWords, b: RHSWords); ++i)
514 Bits[i] &= RHS.Bits[i];
515
516 // Any bits that are just in this bitvector become zero, because they aren't
517 // in the RHS bit vector. Any words only in RHS are ignored because they
518 // are already zero in the LHS.
519 for (; i != ThisWords; ++i)
520 Bits[i] = 0;
521
522 return *this;
523 }
524
525 /// reset - Reset bits that are set in RHS. Same as *this &= ~RHS.
526 BitVector &reset(const BitVector &RHS) {
527 unsigned ThisWords = Bits.size();
528 unsigned RHSWords = RHS.Bits.size();
529 for (unsigned i = 0; i != std::min(a: ThisWords, b: RHSWords); ++i)
530 Bits[i] &= ~RHS.Bits[i];
531 return *this;
532 }
533
534 /// test - Check if (This - RHS) is zero.
535 /// This is the same as reset(RHS) and any().
536 bool test(const BitVector &RHS) const {
537 unsigned ThisWords = Bits.size();
538 unsigned RHSWords = RHS.Bits.size();
539 unsigned i;
540 for (i = 0; i != std::min(a: ThisWords, b: RHSWords); ++i)
541 if ((Bits[i] & ~RHS.Bits[i]) != 0)
542 return true;
543
544 for (; i != ThisWords ; ++i)
545 if (Bits[i] != 0)
546 return true;
547
548 return false;
549 }
550
551 template <class F, class... ArgTys>
552 static BitVector &apply(F &&f, BitVector &Out, BitVector const &Arg,
553 ArgTys const &...Args) {
554 assert(llvm::all_of(
555 std::initializer_list<unsigned>{Args.size()...},
556 [&Arg](auto const &BV) { return Arg.size() == BV; }) &&
557 "consistent sizes");
558 Out.resize(N: Arg.size());
559 for (size_type I = 0, E = Arg.Bits.size(); I != E; ++I)
560 Out.Bits[I] = f(Arg.Bits[I], Args.Bits[I]...);
561 Out.clear_unused_bits();
562 return Out;
563 }
564
565 BitVector &operator|=(const BitVector &RHS) {
566 if (size() < RHS.size())
567 resize(N: RHS.size());
568 for (size_type I = 0, E = RHS.Bits.size(); I != E; ++I)
569 Bits[I] |= RHS.Bits[I];
570 return *this;
571 }
572
573 BitVector &operator^=(const BitVector &RHS) {
574 if (size() < RHS.size())
575 resize(N: RHS.size());
576 for (size_type I = 0, E = RHS.Bits.size(); I != E; ++I)
577 Bits[I] ^= RHS.Bits[I];
578 return *this;
579 }
580
581 BitVector &operator>>=(unsigned N) {
582 assert(N <= Size);
583 if (LLVM_UNLIKELY(empty() || N == 0))
584 return *this;
585
586 unsigned NumWords = Bits.size();
587 assert(NumWords >= 1);
588
589 wordShr(Count: N / BITWORD_SIZE);
590
591 unsigned BitDistance = N % BITWORD_SIZE;
592 if (BitDistance == 0)
593 return *this;
594
595 // When the shift size is not a multiple of the word size, then we have
596 // a tricky situation where each word in succession needs to extract some
597 // of the bits from the next word and or them into this word while
598 // shifting this word to make room for the new bits. This has to be done
599 // for every word in the array.
600
601 // Since we're shifting each word right, some bits will fall off the end
602 // of each word to the right, and empty space will be created on the left.
603 // The final word in the array will lose bits permanently, so starting at
604 // the beginning, work forwards shifting each word to the right, and
605 // OR'ing in the bits from the end of the next word to the beginning of
606 // the current word.
607
608 // Example:
609 // Starting with {0xAABBCCDD, 0xEEFF0011, 0x22334455} and shifting right
610 // by 4 bits.
611 // Step 1: Word[0] >>= 4 ; 0x0ABBCCDD
612 // Step 2: Word[0] |= 0x10000000 ; 0x1ABBCCDD
613 // Step 3: Word[1] >>= 4 ; 0x0EEFF001
614 // Step 4: Word[1] |= 0x50000000 ; 0x5EEFF001
615 // Step 5: Word[2] >>= 4 ; 0x02334455
616 // Result: { 0x1ABBCCDD, 0x5EEFF001, 0x02334455 }
617 const BitWord Mask = maskTrailingOnes<BitWord>(N: BitDistance);
618 const unsigned LSH = BITWORD_SIZE - BitDistance;
619
620 for (unsigned I = 0; I < NumWords - 1; ++I) {
621 Bits[I] >>= BitDistance;
622 Bits[I] |= (Bits[I + 1] & Mask) << LSH;
623 }
624
625 Bits[NumWords - 1] >>= BitDistance;
626
627 return *this;
628 }
629
630 BitVector &operator<<=(unsigned N) {
631 assert(N <= Size);
632 if (LLVM_UNLIKELY(empty() || N == 0))
633 return *this;
634
635 unsigned NumWords = Bits.size();
636 assert(NumWords >= 1);
637
638 wordShl(Count: N / BITWORD_SIZE);
639
640 unsigned BitDistance = N % BITWORD_SIZE;
641 if (BitDistance == 0)
642 return *this;
643
644 // When the shift size is not a multiple of the word size, then we have
645 // a tricky situation where each word in succession needs to extract some
646 // of the bits from the previous word and or them into this word while
647 // shifting this word to make room for the new bits. This has to be done
648 // for every word in the array. This is similar to the algorithm outlined
649 // in operator>>=, but backwards.
650
651 // Since we're shifting each word left, some bits will fall off the end
652 // of each word to the left, and empty space will be created on the right.
653 // The first word in the array will lose bits permanently, so starting at
654 // the end, work backwards shifting each word to the left, and OR'ing
655 // in the bits from the end of the next word to the beginning of the
656 // current word.
657
658 // Example:
659 // Starting with {0xAABBCCDD, 0xEEFF0011, 0x22334455} and shifting left
660 // by 4 bits.
661 // Step 1: Word[2] <<= 4 ; 0x23344550
662 // Step 2: Word[2] |= 0x0000000E ; 0x2334455E
663 // Step 3: Word[1] <<= 4 ; 0xEFF00110
664 // Step 4: Word[1] |= 0x0000000A ; 0xEFF0011A
665 // Step 5: Word[0] <<= 4 ; 0xABBCCDD0
666 // Result: { 0xABBCCDD0, 0xEFF0011A, 0x2334455E }
667 const BitWord Mask = maskLeadingOnes<BitWord>(N: BitDistance);
668 const unsigned RSH = BITWORD_SIZE - BitDistance;
669
670 for (int I = NumWords - 1; I > 0; --I) {
671 Bits[I] <<= BitDistance;
672 Bits[I] |= (Bits[I - 1] & Mask) >> RSH;
673 }
674 Bits[0] <<= BitDistance;
675 clear_unused_bits();
676
677 return *this;
678 }
679
680 void swap(BitVector &RHS) {
681 std::swap(LHS&: Bits, RHS&: RHS.Bits);
682 std::swap(a&: Size, b&: RHS.Size);
683 }
684
685 void invalid() {
686 assert(!Size && Bits.empty());
687 Size = (unsigned)-1;
688 }
689 bool isInvalid() const { return Size == (unsigned)-1; }
690
691 ArrayRef<BitWord> getData() const { return {&Bits[0], Bits.size()}; }
692
693 //===--------------------------------------------------------------------===//
694 // Portable bit mask operations.
695 //===--------------------------------------------------------------------===//
696 //
697 // These methods all operate on arrays of uint32_t, each holding 32 bits. The
698 // fixed word size makes it easier to work with literal bit vector constants
699 // in portable code.
700 //
701 // The LSB in each word is the lowest numbered bit. The size of a portable
702 // bit mask is always a whole multiple of 32 bits. If no bit mask size is
703 // given, the bit mask is assumed to cover the entire BitVector.
704
705 /// setBitsInMask - Add '1' bits from Mask to this vector. Don't resize.
706 /// This computes "*this |= Mask".
707 void setBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
708 applyMask<true, false>(Mask, MaskWords);
709 }
710
711 /// clearBitsInMask - Clear any bits in this vector that are set in Mask.
712 /// Don't resize. This computes "*this &= ~Mask".
713 void clearBitsInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
714 applyMask<false, false>(Mask, MaskWords);
715 }
716
717 /// setBitsNotInMask - Add a bit to this vector for every '0' bit in Mask.
718 /// Don't resize. This computes "*this |= ~Mask".
719 void setBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
720 applyMask<true, true>(Mask, MaskWords);
721 }
722
723 /// clearBitsNotInMask - Clear a bit in this vector for every '0' bit in Mask.
724 /// Don't resize. This computes "*this &= Mask".
725 void clearBitsNotInMask(const uint32_t *Mask, unsigned MaskWords = ~0u) {
726 applyMask<false, true>(Mask, MaskWords);
727 }
728
729private:
730 /// Perform a logical left shift of \p Count words by moving everything
731 /// \p Count words to the right in memory.
732 ///
733 /// While confusing, words are stored from least significant at Bits[0] to
734 /// most significant at Bits[NumWords-1]. A logical shift left, however,
735 /// moves the current least significant bit to a higher logical index, and
736 /// fills the previous least significant bits with 0. Thus, we actually
737 /// need to move the bytes of the memory to the right, not to the left.
738 /// Example:
739 /// Words = [0xBBBBAAAA, 0xDDDDFFFF, 0x00000000, 0xDDDD0000]
740 /// represents a BitVector where 0xBBBBAAAA contain the least significant
741 /// bits. So if we want to shift the BitVector left by 2 words, we need
742 /// to turn this into 0x00000000 0x00000000 0xBBBBAAAA 0xDDDDFFFF by using a
743 /// memmove which moves right, not left.
744 void wordShl(uint32_t Count) {
745 if (Count == 0)
746 return;
747
748 uint32_t NumWords = Bits.size();
749
750 // Since we always move Word-sized chunks of data with src and dest both
751 // aligned to a word-boundary, we don't need to worry about endianness
752 // here.
753 std::copy(first: Bits.begin(), last: Bits.begin() + NumWords - Count,
754 result: Bits.begin() + Count);
755 std::fill(first: Bits.begin(), last: Bits.begin() + Count, value: 0);
756 clear_unused_bits();
757 }
758
759 /// Perform a logical right shift of \p Count words by moving those
760 /// words to the left in memory. See wordShl for more information.
761 ///
762 void wordShr(uint32_t Count) {
763 if (Count == 0)
764 return;
765
766 uint32_t NumWords = Bits.size();
767
768 std::copy(first: Bits.begin() + Count, last: Bits.begin() + NumWords, result: Bits.begin());
769 std::fill(first: Bits.begin() + NumWords - Count, last: Bits.begin() + NumWords, value: 0);
770 }
771
772 int next_unset_in_word(int WordIndex, BitWord Word) const {
773 unsigned Result = WordIndex * BITWORD_SIZE + llvm::countr_one(Value: Word);
774 return Result < size() ? Result : -1;
775 }
776
777 unsigned NumBitWords(unsigned S) const {
778 return (S + BITWORD_SIZE-1) / BITWORD_SIZE;
779 }
780
781 // Set the unused bits in the high words.
782 void set_unused_bits(bool t = true) {
783 // Then set any stray high bits of the last used word.
784 if (unsigned ExtraBits = Size % BITWORD_SIZE) {
785 BitWord ExtraBitMask = ~BitWord(0) << ExtraBits;
786 if (t)
787 Bits.back() |= ExtraBitMask;
788 else
789 Bits.back() &= ~ExtraBitMask;
790 }
791 }
792
793 // Clear the unused bits in the high words.
794 void clear_unused_bits() {
795 set_unused_bits(false);
796 }
797
798 void init_words(bool t) {
799 std::fill(first: Bits.begin(), last: Bits.end(), value: 0 - (BitWord)t);
800 }
801
802 template<bool AddBits, bool InvertMask>
803 void applyMask(const uint32_t *Mask, unsigned MaskWords) {
804 static_assert(BITWORD_SIZE % 32 == 0, "Unsupported BitWord size.");
805 MaskWords = std::min(a: MaskWords, b: (size() + 31) / 32);
806 const unsigned Scale = BITWORD_SIZE / 32;
807 unsigned i;
808 for (i = 0; MaskWords >= Scale; ++i, MaskWords -= Scale) {
809 BitWord BW = Bits[i];
810 // This inner loop should unroll completely when BITWORD_SIZE > 32.
811 for (unsigned b = 0; b != BITWORD_SIZE; b += 32) {
812 uint32_t M = *Mask++;
813 if (InvertMask) M = ~M;
814 if (AddBits) BW |= BitWord(M) << b;
815 else BW &= ~(BitWord(M) << b);
816 }
817 Bits[i] = BW;
818 }
819 for (unsigned b = 0; MaskWords; b += 32, --MaskWords) {
820 uint32_t M = *Mask++;
821 if (InvertMask) M = ~M;
822 if (AddBits) Bits[i] |= BitWord(M) << b;
823 else Bits[i] &= ~(BitWord(M) << b);
824 }
825 if (AddBits)
826 clear_unused_bits();
827 }
828
829public:
830 /// Return the size (in bytes) of the bit vector.
831 size_type getMemorySize() const { return Bits.size() * sizeof(BitWord); }
832 size_type getBitCapacity() const { return Bits.size() * BITWORD_SIZE; }
833};
834
835inline BitVector::size_type capacity_in_bytes(const BitVector &X) {
836 return X.getMemorySize();
837}
838
839template <> struct DenseMapInfo<BitVector> {
840 static inline BitVector getEmptyKey() { return {}; }
841 static inline BitVector getTombstoneKey() {
842 BitVector V;
843 V.invalid();
844 return V;
845 }
846 static unsigned getHashValue(const BitVector &V) {
847 return DenseMapInfo<std::pair<BitVector::size_type, ArrayRef<uintptr_t>>>::
848 getHashValue(PairVal: std::make_pair(x: V.size(), y: V.getData()));
849 }
850 static bool isEqual(const BitVector &LHS, const BitVector &RHS) {
851 if (LHS.isInvalid() || RHS.isInvalid())
852 return LHS.isInvalid() == RHS.isInvalid();
853 return LHS == RHS;
854 }
855};
856} // end namespace llvm
857
858namespace std {
859 /// Implement std::swap in terms of BitVector swap.
860inline void swap(llvm::BitVector &LHS, llvm::BitVector &RHS) { LHS.swap(RHS); }
861} // end namespace std
862
863#endif // LLVM_ADT_BITVECTOR_H
864

source code of include/llvm-17/llvm/ADT/BitVector.h