1 /*
2 * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "memory/allocation.inline.hpp"
27 #include "memory/resourceArea.hpp"
28 #include "runtime/atomic.hpp"
29 #include "utilities/bitMap.inline.hpp"
30 #include "utilities/copy.hpp"
31 #include "utilities/debug.hpp"
32
33 STATIC_ASSERT(sizeof(BitMap::bm_word_t) == BytesPerWord); // "Implementation assumption."
34
35 typedef BitMap::bm_word_t bm_word_t;
36 typedef BitMap::idx_t idx_t;
37
38 class ResourceBitMapAllocator : StackObj {
39 public:
40 bm_word_t* allocate(idx_t size_in_words) const {
41 return NEW_RESOURCE_ARRAY(bm_word_t, size_in_words);
42 }
43 void free(bm_word_t* map, idx_t size_in_words) const {
44 // Don't free resource allocated arrays.
45 }
46 };
47
48 class CHeapBitMapAllocator : StackObj {
49 MEMFLAGS _flags;
50
51 public:
52 CHeapBitMapAllocator(MEMFLAGS flags) : _flags(flags) {}
53 bm_word_t* allocate(size_t size_in_words) const {
54 return ArrayAllocator<bm_word_t>::allocate(size_in_words, _flags);
55 }
56 void free(bm_word_t* map, idx_t size_in_words) const {
57 ArrayAllocator<bm_word_t>::free(map, size_in_words);
58 }
59 };
60
61 class ArenaBitMapAllocator : StackObj {
62 Arena* _arena;
63
64 public:
65 ArenaBitMapAllocator(Arena* arena) : _arena(arena) {}
66 bm_word_t* allocate(idx_t size_in_words) const {
67 return (bm_word_t*)_arena->Amalloc(size_in_words * BytesPerWord);
68 }
69 void free(bm_word_t* map, idx_t size_in_words) const {
70 // ArenaBitMaps currently don't free memory.
71 }
72 };
73
74 template <class Allocator>
75 BitMap::bm_word_t* BitMap::reallocate(const Allocator& allocator, bm_word_t* old_map, idx_t old_size_in_bits, idx_t new_size_in_bits) {
76 size_t old_size_in_words = calc_size_in_words(old_size_in_bits);
77 size_t new_size_in_words = calc_size_in_words(new_size_in_bits);
78
79 bm_word_t* map = NULL;
80
81 if (new_size_in_words > 0) {
82 map = allocator.allocate(new_size_in_words);
83
84 if (old_map != NULL) {
85 Copy::disjoint_words((HeapWord*)old_map, (HeapWord*) map,
86 MIN2(old_size_in_words, new_size_in_words));
87 }
88
89 if (new_size_in_words > old_size_in_words) {
90 clear_range_of_words(map, old_size_in_words, new_size_in_words);
91 }
92 }
93
94 if (old_map != NULL) {
95 allocator.free(old_map, old_size_in_words);
96 }
97
98 return map;
99 }
100
101 template <class Allocator>
102 bm_word_t* BitMap::allocate(const Allocator& allocator, idx_t size_in_bits) {
103 // Reuse reallocate to ensure that the new memory is cleared.
104 return reallocate(allocator, NULL, 0, size_in_bits);
105 }
106
107 template <class Allocator>
108 void BitMap::free(const Allocator& allocator, bm_word_t* map, idx_t size_in_bits) {
109 bm_word_t* ret = reallocate(allocator, map, size_in_bits, 0);
110 assert(ret == NULL, "Reallocate shouldn't have allocated");
111 }
112
113 template <class Allocator>
114 void BitMap::resize(const Allocator& allocator, idx_t new_size_in_bits) {
115 bm_word_t* new_map = reallocate(allocator, map(), size(), new_size_in_bits);
116
117 update(new_map, new_size_in_bits);
118 }
119
120 template <class Allocator>
121 void BitMap::initialize(const Allocator& allocator, idx_t size_in_bits) {
122 assert(map() == NULL, "precondition");
123 assert(size() == 0, "precondition");
124
125 resize(allocator, size_in_bits);
126 }
127
128 template <class Allocator>
129 void BitMap::reinitialize(const Allocator& allocator, idx_t new_size_in_bits) {
130 // Remove previous bits.
131 resize(allocator, 0);
132
133 initialize(allocator, new_size_in_bits);
134 }
135
136 ResourceBitMap::ResourceBitMap(idx_t size_in_bits)
137 : BitMap(allocate(ResourceBitMapAllocator(), size_in_bits), size_in_bits) {
138 }
139
140 void ResourceBitMap::resize(idx_t new_size_in_bits) {
141 BitMap::resize(ResourceBitMapAllocator(), new_size_in_bits);
142 }
143
144 void ResourceBitMap::initialize(idx_t size_in_bits) {
145 BitMap::initialize(ResourceBitMapAllocator(), size_in_bits);
146 }
147
148 void ResourceBitMap::reinitialize(idx_t size_in_bits) {
149 BitMap::reinitialize(ResourceBitMapAllocator(), size_in_bits);
150 }
151
152 ArenaBitMap::ArenaBitMap(Arena* arena, idx_t size_in_bits)
153 : BitMap(allocate(ArenaBitMapAllocator(arena), size_in_bits), size_in_bits) {
154 }
155
156 CHeapBitMap::CHeapBitMap(idx_t size_in_bits, MEMFLAGS flags)
157 : BitMap(allocate(CHeapBitMapAllocator(flags), size_in_bits), size_in_bits), _flags(flags) {
158 }
159
160 CHeapBitMap::~CHeapBitMap() {
161 free(CHeapBitMapAllocator(_flags), map(), size());
162 }
163
164 void CHeapBitMap::resize(idx_t new_size_in_bits) {
165 BitMap::resize(CHeapBitMapAllocator(_flags), new_size_in_bits);
166 }
167
168 void CHeapBitMap::initialize(idx_t size_in_bits) {
169 BitMap::initialize(CHeapBitMapAllocator(_flags), size_in_bits);
170 }
171
172 void CHeapBitMap::reinitialize(idx_t size_in_bits) {
173 BitMap::reinitialize(CHeapBitMapAllocator(_flags), size_in_bits);
174 }
175
176 #ifdef ASSERT
177 void BitMap::verify_index(idx_t index) const {
178 assert(index < _size, "BitMap index out of bounds");
179 }
180
181 void BitMap::verify_range(idx_t beg_index, idx_t end_index) const {
182 assert(beg_index <= end_index, "BitMap range error");
183 // Note that [0,0) and [size,size) are both valid ranges.
184 if (end_index != _size) verify_index(end_index);
185 }
186 #endif // #ifdef ASSERT
187
188 void BitMap::pretouch() {
189 os::pretouch_memory(word_addr(0), word_addr(size()));
190 }
191
192 void BitMap::set_range_within_word(idx_t beg, idx_t end) {
193 // With a valid range (beg <= end), this test ensures that end != 0, as
194 // required by inverted_bit_mask_for_range. Also avoids an unnecessary write.
195 if (beg != end) {
196 bm_word_t mask = inverted_bit_mask_for_range(beg, end);
197 *word_addr(beg) |= ~mask;
198 }
199 }
200
201 void BitMap::clear_range_within_word(idx_t beg, idx_t end) {
202 // With a valid range (beg <= end), this test ensures that end != 0, as
203 // required by inverted_bit_mask_for_range. Also avoids an unnecessary write.
204 if (beg != end) {
205 bm_word_t mask = inverted_bit_mask_for_range(beg, end);
206 *word_addr(beg) &= mask;
207 }
208 }
209
210 void BitMap::par_put_range_within_word(idx_t beg, idx_t end, bool value) {
211 assert(value == 0 || value == 1, "0 for clear, 1 for set");
212 // With a valid range (beg <= end), this test ensures that end != 0, as
213 // required by inverted_bit_mask_for_range. Also avoids an unnecessary write.
214 if (beg != end) {
215 bm_word_t* pw = word_addr(beg);
216 bm_word_t w = *pw;
217 bm_word_t mr = inverted_bit_mask_for_range(beg, end);
218 bm_word_t nw = value ? (w | ~mr) : (w & mr);
219 while (true) {
220 bm_word_t res = Atomic::cmpxchg(nw, pw, w);
221 if (res == w) break;
222 w = res;
223 nw = value ? (w | ~mr) : (w & mr);
224 }
225 }
226 }
227
228 void BitMap::set_range(idx_t beg, idx_t end) {
229 verify_range(beg, end);
230
231 idx_t beg_full_word = word_index_round_up(beg);
232 idx_t end_full_word = word_index(end);
233
234 if (beg_full_word < end_full_word) {
235 // The range includes at least one full word.
236 set_range_within_word(beg, bit_index(beg_full_word));
237 set_range_of_words(beg_full_word, end_full_word);
238 set_range_within_word(bit_index(end_full_word), end);
239 } else {
240 // The range spans at most 2 partial words.
241 idx_t boundary = MIN2(bit_index(beg_full_word), end);
242 set_range_within_word(beg, boundary);
243 set_range_within_word(boundary, end);
244 }
245 }
246
247 void BitMap::clear_range(idx_t beg, idx_t end) {
248 verify_range(beg, end);
249
250 idx_t beg_full_word = word_index_round_up(beg);
251 idx_t end_full_word = word_index(end);
252
253 if (beg_full_word < end_full_word) {
254 // The range includes at least one full word.
255 clear_range_within_word(beg, bit_index(beg_full_word));
256 clear_range_of_words(beg_full_word, end_full_word);
257 clear_range_within_word(bit_index(end_full_word), end);
258 } else {
259 // The range spans at most 2 partial words.
260 idx_t boundary = MIN2(bit_index(beg_full_word), end);
261 clear_range_within_word(beg, boundary);
262 clear_range_within_word(boundary, end);
263 }
264 }
265
266 void BitMap::set_large_range(idx_t beg, idx_t end) {
267 verify_range(beg, end);
268
269 idx_t beg_full_word = word_index_round_up(beg);
270 idx_t end_full_word = word_index(end);
271
272 assert(end_full_word - beg_full_word >= 32,
273 "the range must include at least 32 bytes");
274
275 // The range includes at least one full word.
276 set_range_within_word(beg, bit_index(beg_full_word));
277 set_large_range_of_words(beg_full_word, end_full_word);
278 set_range_within_word(bit_index(end_full_word), end);
279 }
280
281 void BitMap::clear_large_range(idx_t beg, idx_t end) {
282 verify_range(beg, end);
283
284 idx_t beg_full_word = word_index_round_up(beg);
285 idx_t end_full_word = word_index(end);
286
287 if (end_full_word - beg_full_word < 32) {
288 clear_range(beg, end);
289 return;
290 }
291
292 // The range includes at least one full word.
293 clear_range_within_word(beg, bit_index(beg_full_word));
294 clear_large_range_of_words(beg_full_word, end_full_word);
295 clear_range_within_word(bit_index(end_full_word), end);
296 }
297
298 void BitMap::at_put(idx_t offset, bool value) {
299 if (value) {
300 set_bit(offset);
301 } else {
302 clear_bit(offset);
303 }
304 }
305
306 // Return true to indicate that this thread changed
307 // the bit, false to indicate that someone else did.
308 // In either case, the requested bit is in the
309 // requested state some time during the period that
310 // this thread is executing this call. More importantly,
311 // if no other thread is executing an action to
312 // change the requested bit to a state other than
313 // the one that this thread is trying to set it to,
314 // then the the bit is in the expected state
315 // at exit from this method. However, rather than
316 // make such a strong assertion here, based on
317 // assuming such constrained use (which though true
318 // today, could change in the future to service some
319 // funky parallel algorithm), we encourage callers
320 // to do such verification, as and when appropriate.
321 bool BitMap::par_at_put(idx_t bit, bool value) {
322 return value ? par_set_bit(bit) : par_clear_bit(bit);
323 }
324
325 void BitMap::at_put_range(idx_t start_offset, idx_t end_offset, bool value) {
326 if (value) {
327 set_range(start_offset, end_offset);
328 } else {
329 clear_range(start_offset, end_offset);
330 }
331 }
332
333 void BitMap::par_at_put_range(idx_t beg, idx_t end, bool value) {
334 verify_range(beg, end);
335
336 idx_t beg_full_word = word_index_round_up(beg);
337 idx_t end_full_word = word_index(end);
338
339 if (beg_full_word < end_full_word) {
340 // The range includes at least one full word.
341 par_put_range_within_word(beg, bit_index(beg_full_word), value);
342 if (value) {
343 set_range_of_words(beg_full_word, end_full_word);
344 } else {
345 clear_range_of_words(beg_full_word, end_full_word);
346 }
347 par_put_range_within_word(bit_index(end_full_word), end, value);
348 } else {
349 // The range spans at most 2 partial words.
350 idx_t boundary = MIN2(bit_index(beg_full_word), end);
351 par_put_range_within_word(beg, boundary, value);
352 par_put_range_within_word(boundary, end, value);
353 }
354
355 }
356
357 void BitMap::at_put_large_range(idx_t beg, idx_t end, bool value) {
358 if (value) {
359 set_large_range(beg, end);
360 } else {
361 clear_large_range(beg, end);
362 }
363 }
364
365 void BitMap::par_at_put_large_range(idx_t beg, idx_t end, bool value) {
366 verify_range(beg, end);
367
368 idx_t beg_full_word = word_index_round_up(beg);
369 idx_t end_full_word = word_index(end);
370
371 assert(end_full_word - beg_full_word >= 32,
372 "the range must include at least 32 bytes");
373
374 // The range includes at least one full word.
375 par_put_range_within_word(beg, bit_index(beg_full_word), value);
376 if (value) {
377 set_large_range_of_words(beg_full_word, end_full_word);
378 } else {
379 clear_large_range_of_words(beg_full_word, end_full_word);
380 }
381 par_put_range_within_word(bit_index(end_full_word), end, value);
382 }
383
384 inline bm_word_t tail_mask(idx_t tail_bits) {
385 assert(tail_bits != 0, "precondition"); // Works, but shouldn't be called.
386 assert(tail_bits < (idx_t)BitsPerWord, "precondition");
387 return (bm_word_t(1) << tail_bits) - 1;
388 }
389
390 // Get the low tail_bits of value, which is the last partial word of a map.
391 inline bm_word_t tail_of_map(bm_word_t value, idx_t tail_bits) {
392 return value & tail_mask(tail_bits);
393 }
394
395 // Compute the new last word of a map with a non-aligned length.
396 // new_value has the new trailing bits of the map in the low tail_bits.
397 // old_value is the last word of the map, including bits beyond the end.
398 // Returns old_value with the low tail_bits replaced by the corresponding
399 // bits in new_value.
400 inline bm_word_t merge_tail_of_map(bm_word_t new_value,
401 bm_word_t old_value,
402 idx_t tail_bits) {
403 bm_word_t mask = tail_mask(tail_bits);
404 return (new_value & mask) | (old_value & ~mask);
405 }
406
407 bool BitMap::contains(const BitMap& other) const {
408 assert(size() == other.size(), "must have same size");
409 const bm_word_t* dest_map = map();
410 const bm_word_t* other_map = other.map();
411 idx_t limit = word_index(size());
412 for (idx_t index = 0; index < limit; ++index) {
413 // false if other bitmap has bits set which are clear in this bitmap.
414 if ((~dest_map[index] & other_map[index]) != 0) return false;
415 }
416 idx_t rest = bit_in_word(size());
417 // true unless there is a partial-word tail in which the other
418 // bitmap has bits set which are clear in this bitmap.
419 return (rest == 0) || tail_of_map(~dest_map[limit] & other_map[limit], rest) == 0;
420 }
421
422 bool BitMap::intersects(const BitMap& other) const {
423 assert(size() == other.size(), "must have same size");
424 const bm_word_t* dest_map = map();
425 const bm_word_t* other_map = other.map();
426 idx_t limit = word_index(size());
427 for (idx_t index = 0; index < limit; ++index) {
428 if ((dest_map[index] & other_map[index]) != 0) return true;
429 }
430 idx_t rest = bit_in_word(size());
431 // false unless there is a partial-word tail with non-empty intersection.
432 return (rest > 0) && tail_of_map(dest_map[limit] & other_map[limit], rest) != 0;
433 }
434
435 void BitMap::set_union(const BitMap& other) {
436 assert(size() == other.size(), "must have same size");
437 bm_word_t* dest_map = map();
438 const bm_word_t* other_map = other.map();
439 idx_t limit = word_index(size());
440 for (idx_t index = 0; index < limit; ++index) {
441 dest_map[index] |= other_map[index];
442 }
443 idx_t rest = bit_in_word(size());
444 if (rest > 0) {
445 bm_word_t orig = dest_map[limit];
446 dest_map[limit] = merge_tail_of_map(orig | other_map[limit], orig, rest);
447 }
448 }
449
450 void BitMap::set_difference(const BitMap& other) {
451 assert(size() == other.size(), "must have same size");
452 bm_word_t* dest_map = map();
453 const bm_word_t* other_map = other.map();
454 idx_t limit = word_index(size());
455 for (idx_t index = 0; index < limit; ++index) {
456 dest_map[index] &= ~other_map[index];
457 }
458 idx_t rest = bit_in_word(size());
459 if (rest > 0) {
460 bm_word_t orig = dest_map[limit];
461 dest_map[limit] = merge_tail_of_map(orig & ~other_map[limit], orig, rest);
462 }
463 }
464
465 void BitMap::set_intersection(const BitMap& other) {
466 assert(size() == other.size(), "must have same size");
467 bm_word_t* dest_map = map();
468 const bm_word_t* other_map = other.map();
469 idx_t limit = word_index(size());
470 for (idx_t index = 0; index < limit; ++index) {
471 dest_map[index] &= other_map[index];
472 }
473 idx_t rest = bit_in_word(size());
474 if (rest > 0) {
475 bm_word_t orig = dest_map[limit];
476 dest_map[limit] = merge_tail_of_map(orig & other_map[limit], orig, rest);
477 }
478 }
479
480 bool BitMap::set_union_with_result(const BitMap& other) {
481 assert(size() == other.size(), "must have same size");
482 bool changed = false;
483 bm_word_t* dest_map = map();
484 const bm_word_t* other_map = other.map();
485 idx_t limit = word_index(size());
486 for (idx_t index = 0; index < limit; ++index) {
487 bm_word_t orig = dest_map[index];
488 bm_word_t temp = orig | other_map[index];
489 changed = changed || (temp != orig);
490 dest_map[index] = temp;
491 }
492 idx_t rest = bit_in_word(size());
493 if (rest > 0) {
494 bm_word_t orig = dest_map[limit];
495 bm_word_t temp = merge_tail_of_map(orig | other_map[limit], orig, rest);
496 changed = changed || (temp != orig);
497 dest_map[limit] = temp;
498 }
499 return changed;
500 }
501
502 bool BitMap::set_difference_with_result(const BitMap& other) {
503 assert(size() == other.size(), "must have same size");
504 bool changed = false;
505 bm_word_t* dest_map = map();
506 const bm_word_t* other_map = other.map();
507 idx_t limit = word_index(size());
508 for (idx_t index = 0; index < limit; ++index) {
509 bm_word_t orig = dest_map[index];
510 bm_word_t temp = orig & ~other_map[index];
511 changed = changed || (temp != orig);
512 dest_map[index] = temp;
513 }
514 idx_t rest = bit_in_word(size());
515 if (rest > 0) {
516 bm_word_t orig = dest_map[limit];
517 bm_word_t temp = merge_tail_of_map(orig & ~other_map[limit], orig, rest);
518 changed = changed || (temp != orig);
519 dest_map[limit] = temp;
520 }
521 return changed;
522 }
523
524 bool BitMap::set_intersection_with_result(const BitMap& other) {
525 assert(size() == other.size(), "must have same size");
526 bool changed = false;
527 bm_word_t* dest_map = map();
528 const bm_word_t* other_map = other.map();
529 idx_t limit = word_index(size());
530 for (idx_t index = 0; index < limit; ++index) {
531 bm_word_t orig = dest_map[index];
532 bm_word_t temp = orig & other_map[index];
533 changed = changed || (temp != orig);
534 dest_map[index] = temp;
535 }
536 idx_t rest = bit_in_word(size());
537 if (rest > 0) {
538 bm_word_t orig = dest_map[limit];
539 bm_word_t temp = merge_tail_of_map(orig & other_map[limit], orig, rest);
540 changed = changed || (temp != orig);
541 dest_map[limit] = temp;
542 }
543 return changed;
544 }
545
546 void BitMap::set_from(const BitMap& other) {
547 assert(size() == other.size(), "must have same size");
548 bm_word_t* dest_map = map();
549 const bm_word_t* other_map = other.map();
550 idx_t copy_words = word_index(size());
551 Copy::disjoint_words((HeapWord*)other_map, (HeapWord*)dest_map, copy_words);
552 idx_t rest = bit_in_word(size());
553 if (rest > 0) {
554 dest_map[copy_words] = merge_tail_of_map(other_map[copy_words],
555 dest_map[copy_words],
556 rest);
557 }
558 }
559
560 bool BitMap::is_same(const BitMap& other) const {
561 assert(size() == other.size(), "must have same size");
562 const bm_word_t* dest_map = map();
563 const bm_word_t* other_map = other.map();
564 idx_t limit = word_index(size());
565 for (idx_t index = 0; index < limit; ++index) {
566 if (dest_map[index] != other_map[index]) return false;
567 }
568 idx_t rest = bit_in_word(size());
569 return (rest == 0) || (tail_of_map(dest_map[limit] ^ other_map[limit], rest) == 0);
570 }
571
572 bool BitMap::is_full() const {
573 const bm_word_t* words = map();
574 idx_t limit = word_index(size());
575 for (idx_t index = 0; index < limit; ++index) {
576 if (~words[index] != 0) return false;
577 }
578 idx_t rest = bit_in_word(size());
579 return (rest == 0) || (tail_of_map(~words[limit], rest) == 0);
580 }
581
582 bool BitMap::is_empty() const {
583 const bm_word_t* words = map();
584 idx_t limit = word_index(size());
585 for (idx_t index = 0; index < limit; ++index) {
586 if (words[index] != 0) return false;
587 }
588 idx_t rest = bit_in_word(size());
589 return (rest == 0) || (tail_of_map(words[limit], rest) == 0);
590 }
591
592 void BitMap::clear_large() {
593 clear_large_range_of_words(0, size_in_words());
594 }
595
596 // Note that if the closure itself modifies the bitmap
597 // then modifications in and to the left of the _bit_ being
598 // currently sampled will not be seen. Note also that the
599 // interval [leftOffset, rightOffset) is right open.
600 bool BitMap::iterate(BitMapClosure* blk, idx_t leftOffset, idx_t rightOffset) {
601 verify_range(leftOffset, rightOffset);
602
603 idx_t startIndex = word_index(leftOffset);
604 idx_t endIndex = MIN2(word_index(rightOffset) + 1, size_in_words());
605 for (idx_t index = startIndex, offset = leftOffset;
606 offset < rightOffset && index < endIndex;
607 offset = (++index) << LogBitsPerWord) {
608 idx_t rest = map(index) >> (offset & (BitsPerWord - 1));
609 for (; offset < rightOffset && rest != 0; offset++) {
610 if (rest & 1) {
611 if (!blk->do_bit(offset)) return false;
612 // resample at each closure application
613 // (see, for instance, CMS bug 4525989)
614 rest = map(index) >> (offset & (BitsPerWord -1));
615 }
616 rest = rest >> 1;
617 }
618 }
619 return true;
620 }
621
622 const BitMap::idx_t* BitMap::_pop_count_table = NULL;
623
624 void BitMap::init_pop_count_table() {
625 if (_pop_count_table == NULL) {
626 BitMap::idx_t *table = NEW_C_HEAP_ARRAY(idx_t, 256, mtInternal);
627 for (uint i = 0; i < 256; i++) {
628 table[i] = num_set_bits(i);
629 }
630
631 if (!Atomic::replace_if_null(table, &_pop_count_table)) {
632 guarantee(_pop_count_table != NULL, "invariant");
633 FREE_C_HEAP_ARRAY(idx_t, table);
634 }
635 }
636 }
637
638 BitMap::idx_t BitMap::num_set_bits(bm_word_t w) {
639 idx_t bits = 0;
640
641 while (w != 0) {
642 while ((w & 1) == 0) {
643 w >>= 1;
644 }
645 bits++;
646 w >>= 1;
647 }
648 return bits;
649 }
650
651 BitMap::idx_t BitMap::num_set_bits_from_table(unsigned char c) {
652 assert(_pop_count_table != NULL, "precondition");
653 return _pop_count_table[c];
654 }
655
656 BitMap::idx_t BitMap::count_one_bits() const {
657 init_pop_count_table(); // If necessary.
658 idx_t sum = 0;
659 typedef unsigned char uchar;
660 for (idx_t i = 0; i < size_in_words(); i++) {
661 bm_word_t w = map()[i];
662 for (size_t j = 0; j < sizeof(bm_word_t); j++) {
663 sum += num_set_bits_from_table(uchar(w & 255));
664 w >>= 8;
665 }
666 }
667 return sum;
668 }
669
670 void BitMap::print_on_error(outputStream* st, const char* prefix) const {
671 st->print_cr("%s[" PTR_FORMAT ", " PTR_FORMAT ")",
672 prefix, p2i(map()), p2i((char*)map() + (size() >> LogBitsPerByte)));
673 }
674
675 #ifndef PRODUCT
676
677 void BitMap::print_on(outputStream* st) const {
678 tty->print("Bitmap(" SIZE_FORMAT "):", size());
679 for (idx_t index = 0; index < size(); index++) {
680 tty->print("%c", at(index) ? '1' : '0');
681 }
682 tty->cr();
683 }
684
685 #endif