1 /*
2 * Copyright (c) 1997, 2019, 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, bool clear) {
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 (clear && 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, bool clear) {
103 // Reuse reallocate to ensure that the new memory is cleared.
104 return reallocate(allocator, NULL, 0, size_in_bits, clear);
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, bool clear) {
115 bm_word_t* new_map = reallocate(allocator, map(), size(), new_size_in_bits, clear);
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, bool clear) {
122 assert(map() == NULL, "precondition");
123 assert(size() == 0, "precondition");
124
125 resize(allocator, size_in_bits, clear);
126 }
127
128 template <class Allocator>
129 void BitMap::reinitialize(const Allocator& allocator, idx_t new_size_in_bits, bool clear) {
130 // Remove previous bits - no need to clear
131 resize(allocator, 0, false /* clear */);
132
133 initialize(allocator, new_size_in_bits, clear);
134 }
135
136 ResourceBitMap::ResourceBitMap(idx_t size_in_bits, bool clear)
137 : BitMap(allocate(ResourceBitMapAllocator(), size_in_bits, clear), size_in_bits) {
138 }
139
140 void ResourceBitMap::resize(idx_t new_size_in_bits) {
141 BitMap::resize(ResourceBitMapAllocator(), new_size_in_bits, true /* clear */);
142 }
143
144 void ResourceBitMap::initialize(idx_t size_in_bits) {
145 BitMap::initialize(ResourceBitMapAllocator(), size_in_bits, true /* clear */);
146 }
147
148 void ResourceBitMap::reinitialize(idx_t size_in_bits) {
149 BitMap::reinitialize(ResourceBitMapAllocator(), size_in_bits, true /* clear */);
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, bool clear)
157 : BitMap(allocate(CHeapBitMapAllocator(flags), size_in_bits, clear), 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, bool clear) {
165 BitMap::resize(CHeapBitMapAllocator(_flags), new_size_in_bits, clear);
166 }
167
168 void CHeapBitMap::initialize(idx_t size_in_bits, bool clear) {
169 BitMap::initialize(CHeapBitMapAllocator(_flags), size_in_bits, clear);
170 }
171
172 void CHeapBitMap::reinitialize(idx_t size_in_bits, bool clear) {
173 BitMap::reinitialize(CHeapBitMapAllocator(_flags), size_in_bits, clear);
174 }
175
176 #ifdef ASSERT
177 void BitMap::verify_size(idx_t size_in_bits) {
178 assert(size_in_bits <= max_size_in_bits(),
179 "out of bounds: " SIZE_FORMAT, size_in_bits);
180 }
181
182 void BitMap::verify_index(idx_t bit) const {
183 assert(bit < _size,
184 "BitMap index out of bounds: " SIZE_FORMAT " >= " SIZE_FORMAT,
185 bit, _size);
186 }
187
188 void BitMap::verify_limit(idx_t bit) const {
189 assert(bit <= _size,
190 "BitMap limit out of bounds: " SIZE_FORMAT " > " SIZE_FORMAT,
191 bit, _size);
192 }
193
194 void BitMap::verify_range(idx_t beg, idx_t end) const {
195 assert(beg <= end,
196 "BitMap range error: " SIZE_FORMAT " > " SIZE_FORMAT, beg, end);
197 verify_limit(end);
198 }
199 #endif // #ifdef ASSERT
200
201 void BitMap::pretouch() {
202 os::pretouch_memory(word_addr(0), word_addr(size()));
203 }
204
205 void BitMap::set_range_within_word(idx_t beg, idx_t end) {
206 // With a valid range (beg <= end), this test ensures that end != 0, as
207 // required by inverted_bit_mask_for_range. Also avoids an unnecessary write.
208 if (beg != end) {
209 bm_word_t mask = inverted_bit_mask_for_range(beg, end);
210 *word_addr(beg) |= ~mask;
211 }
212 }
213
214 void BitMap::clear_range_within_word(idx_t beg, idx_t end) {
215 // With a valid range (beg <= end), this test ensures that end != 0, as
216 // required by inverted_bit_mask_for_range. Also avoids an unnecessary write.
217 if (beg != end) {
218 bm_word_t mask = inverted_bit_mask_for_range(beg, end);
219 *word_addr(beg) &= mask;
220 }
221 }
222
223 void BitMap::par_put_range_within_word(idx_t beg, idx_t end, bool value) {
224 assert(value == 0 || value == 1, "0 for clear, 1 for set");
225 // With a valid range (beg <= end), this test ensures that end != 0, as
226 // required by inverted_bit_mask_for_range. Also avoids an unnecessary write.
227 if (beg != end) {
228 bm_word_t* pw = word_addr(beg);
229 bm_word_t w = *pw;
230 bm_word_t mr = inverted_bit_mask_for_range(beg, end);
231 bm_word_t nw = value ? (w | ~mr) : (w & mr);
232 while (true) {
233 bm_word_t res = Atomic::cmpxchg(pw, w, nw);
234 if (res == w) break;
235 w = res;
236 nw = value ? (w | ~mr) : (w & mr);
237 }
238 }
239 }
240
241 void BitMap::set_range(idx_t beg, idx_t end) {
242 verify_range(beg, end);
243
244 idx_t beg_full_word = to_words_align_up(beg);
245 idx_t end_full_word = to_words_align_down(end);
246
247 if (beg_full_word < end_full_word) {
248 // The range includes at least one full word.
249 set_range_within_word(beg, bit_index(beg_full_word));
250 set_range_of_words(beg_full_word, end_full_word);
251 set_range_within_word(bit_index(end_full_word), end);
252 } else {
253 // The range spans at most 2 partial words.
254 idx_t boundary = MIN2(bit_index(beg_full_word), end);
255 set_range_within_word(beg, boundary);
256 set_range_within_word(boundary, end);
257 }
258 }
259
260 void BitMap::clear_range(idx_t beg, idx_t end) {
261 verify_range(beg, end);
262
263 idx_t beg_full_word = to_words_align_up(beg);
264 idx_t end_full_word = to_words_align_down(end);
265
266 if (beg_full_word < end_full_word) {
267 // The range includes at least one full word.
268 clear_range_within_word(beg, bit_index(beg_full_word));
269 clear_range_of_words(beg_full_word, end_full_word);
270 clear_range_within_word(bit_index(end_full_word), end);
271 } else {
272 // The range spans at most 2 partial words.
273 idx_t boundary = MIN2(bit_index(beg_full_word), end);
274 clear_range_within_word(beg, boundary);
275 clear_range_within_word(boundary, end);
276 }
277 }
278
279 bool BitMap::is_small_range_of_words(idx_t beg_full_word, idx_t end_full_word) {
280 // There is little point to call large version on small ranges.
281 // Need to check carefully, keeping potential idx_t over/underflow in mind,
282 // because beg_full_word > end_full_word can occur when beg and end are in
283 // the same word.
284 // The threshold should be at least one word.
285 STATIC_ASSERT(small_range_words >= 1);
286 return beg_full_word + small_range_words >= end_full_word;
287 }
288
289 void BitMap::set_large_range(idx_t beg, idx_t end) {
290 verify_range(beg, end);
291
292 idx_t beg_full_word = to_words_align_up(beg);
293 idx_t end_full_word = to_words_align_down(end);
294
295 if (is_small_range_of_words(beg_full_word, end_full_word)) {
296 set_range(beg, end);
297 return;
298 }
299
300 // The range includes at least one full word.
301 set_range_within_word(beg, bit_index(beg_full_word));
302 set_large_range_of_words(beg_full_word, end_full_word);
303 set_range_within_word(bit_index(end_full_word), end);
304 }
305
306 void BitMap::clear_large_range(idx_t beg, idx_t end) {
307 verify_range(beg, end);
308
309 idx_t beg_full_word = to_words_align_up(beg);
310 idx_t end_full_word = to_words_align_down(end);
311
312 if (is_small_range_of_words(beg_full_word, end_full_word)) {
313 clear_range(beg, end);
314 return;
315 }
316
317 // The range includes at least one full word.
318 clear_range_within_word(beg, bit_index(beg_full_word));
319 clear_large_range_of_words(beg_full_word, end_full_word);
320 clear_range_within_word(bit_index(end_full_word), end);
321 }
322
323 void BitMap::at_put(idx_t offset, bool value) {
324 if (value) {
325 set_bit(offset);
326 } else {
327 clear_bit(offset);
328 }
329 }
330
331 // Return true to indicate that this thread changed
332 // the bit, false to indicate that someone else did.
333 // In either case, the requested bit is in the
334 // requested state some time during the period that
335 // this thread is executing this call. More importantly,
336 // if no other thread is executing an action to
337 // change the requested bit to a state other than
338 // the one that this thread is trying to set it to,
339 // then the the bit is in the expected state
340 // at exit from this method. However, rather than
341 // make such a strong assertion here, based on
342 // assuming such constrained use (which though true
343 // today, could change in the future to service some
344 // funky parallel algorithm), we encourage callers
345 // to do such verification, as and when appropriate.
346 bool BitMap::par_at_put(idx_t bit, bool value) {
347 return value ? par_set_bit(bit) : par_clear_bit(bit);
348 }
349
350 void BitMap::at_put_range(idx_t start_offset, idx_t end_offset, bool value) {
351 if (value) {
352 set_range(start_offset, end_offset);
353 } else {
354 clear_range(start_offset, end_offset);
355 }
356 }
357
358 void BitMap::par_at_put_range(idx_t beg, idx_t end, bool value) {
359 verify_range(beg, end);
360
361 idx_t beg_full_word = to_words_align_up(beg);
362 idx_t end_full_word = to_words_align_down(end);
363
364 if (beg_full_word < end_full_word) {
365 // The range includes at least one full word.
366 par_put_range_within_word(beg, bit_index(beg_full_word), value);
367 if (value) {
368 set_range_of_words(beg_full_word, end_full_word);
369 } else {
370 clear_range_of_words(beg_full_word, end_full_word);
371 }
372 par_put_range_within_word(bit_index(end_full_word), end, value);
373 } else {
374 // The range spans at most 2 partial words.
375 idx_t boundary = MIN2(bit_index(beg_full_word), end);
376 par_put_range_within_word(beg, boundary, value);
377 par_put_range_within_word(boundary, end, value);
378 }
379
380 }
381
382 void BitMap::at_put_large_range(idx_t beg, idx_t end, bool value) {
383 if (value) {
384 set_large_range(beg, end);
385 } else {
386 clear_large_range(beg, end);
387 }
388 }
389
390 void BitMap::par_at_put_large_range(idx_t beg, idx_t end, bool value) {
391 verify_range(beg, end);
392
393 idx_t beg_full_word = to_words_align_up(beg);
394 idx_t end_full_word = to_words_align_down(end);
395
396 if (is_small_range_of_words(beg_full_word, end_full_word)) {
397 par_at_put_range(beg, end, value);
398 return;
399 }
400
401 // The range includes at least one full word.
402 par_put_range_within_word(beg, bit_index(beg_full_word), value);
403 if (value) {
404 set_large_range_of_words(beg_full_word, end_full_word);
405 } else {
406 clear_large_range_of_words(beg_full_word, end_full_word);
407 }
408 par_put_range_within_word(bit_index(end_full_word), end, value);
409 }
410
411 inline bm_word_t tail_mask(idx_t tail_bits) {
412 assert(tail_bits != 0, "precondition"); // Works, but shouldn't be called.
413 assert(tail_bits < (idx_t)BitsPerWord, "precondition");
414 return (bm_word_t(1) << tail_bits) - 1;
415 }
416
417 // Get the low tail_bits of value, which is the last partial word of a map.
418 inline bm_word_t tail_of_map(bm_word_t value, idx_t tail_bits) {
419 return value & tail_mask(tail_bits);
420 }
421
422 // Compute the new last word of a map with a non-aligned length.
423 // new_value has the new trailing bits of the map in the low tail_bits.
424 // old_value is the last word of the map, including bits beyond the end.
425 // Returns old_value with the low tail_bits replaced by the corresponding
426 // bits in new_value.
427 inline bm_word_t merge_tail_of_map(bm_word_t new_value,
428 bm_word_t old_value,
429 idx_t tail_bits) {
430 bm_word_t mask = tail_mask(tail_bits);
431 return (new_value & mask) | (old_value & ~mask);
432 }
433
434 bool BitMap::contains(const BitMap& other) const {
435 assert(size() == other.size(), "must have same size");
436 const bm_word_t* dest_map = map();
437 const bm_word_t* other_map = other.map();
438 idx_t limit = to_words_align_down(size());
439 for (idx_t index = 0; index < limit; ++index) {
440 // false if other bitmap has bits set which are clear in this bitmap.
441 if ((~dest_map[index] & other_map[index]) != 0) return false;
442 }
443 idx_t rest = bit_in_word(size());
444 // true unless there is a partial-word tail in which the other
445 // bitmap has bits set which are clear in this bitmap.
446 return (rest == 0) || tail_of_map(~dest_map[limit] & other_map[limit], rest) == 0;
447 }
448
449 bool BitMap::intersects(const BitMap& other) const {
450 assert(size() == other.size(), "must have same size");
451 const bm_word_t* dest_map = map();
452 const bm_word_t* other_map = other.map();
453 idx_t limit = to_words_align_down(size());
454 for (idx_t index = 0; index < limit; ++index) {
455 if ((dest_map[index] & other_map[index]) != 0) return true;
456 }
457 idx_t rest = bit_in_word(size());
458 // false unless there is a partial-word tail with non-empty intersection.
459 return (rest > 0) && tail_of_map(dest_map[limit] & other_map[limit], rest) != 0;
460 }
461
462 void BitMap::set_union(const BitMap& other) {
463 assert(size() == other.size(), "must have same size");
464 bm_word_t* dest_map = map();
465 const bm_word_t* other_map = other.map();
466 idx_t limit = to_words_align_down(size());
467 for (idx_t index = 0; index < limit; ++index) {
468 dest_map[index] |= other_map[index];
469 }
470 idx_t rest = bit_in_word(size());
471 if (rest > 0) {
472 bm_word_t orig = dest_map[limit];
473 dest_map[limit] = merge_tail_of_map(orig | other_map[limit], orig, rest);
474 }
475 }
476
477 void BitMap::set_difference(const BitMap& other) {
478 assert(size() == other.size(), "must have same size");
479 bm_word_t* dest_map = map();
480 const bm_word_t* other_map = other.map();
481 idx_t limit = to_words_align_down(size());
482 for (idx_t index = 0; index < limit; ++index) {
483 dest_map[index] &= ~other_map[index];
484 }
485 idx_t rest = bit_in_word(size());
486 if (rest > 0) {
487 bm_word_t orig = dest_map[limit];
488 dest_map[limit] = merge_tail_of_map(orig & ~other_map[limit], orig, rest);
489 }
490 }
491
492 void BitMap::set_intersection(const BitMap& other) {
493 assert(size() == other.size(), "must have same size");
494 bm_word_t* dest_map = map();
495 const bm_word_t* other_map = other.map();
496 idx_t limit = to_words_align_down(size());
497 for (idx_t index = 0; index < limit; ++index) {
498 dest_map[index] &= other_map[index];
499 }
500 idx_t rest = bit_in_word(size());
501 if (rest > 0) {
502 bm_word_t orig = dest_map[limit];
503 dest_map[limit] = merge_tail_of_map(orig & other_map[limit], orig, rest);
504 }
505 }
506
507 bool BitMap::set_union_with_result(const BitMap& other) {
508 assert(size() == other.size(), "must have same size");
509 bool changed = false;
510 bm_word_t* dest_map = map();
511 const bm_word_t* other_map = other.map();
512 idx_t limit = to_words_align_down(size());
513 for (idx_t index = 0; index < limit; ++index) {
514 bm_word_t orig = dest_map[index];
515 bm_word_t temp = orig | other_map[index];
516 changed = changed || (temp != orig);
517 dest_map[index] = temp;
518 }
519 idx_t rest = bit_in_word(size());
520 if (rest > 0) {
521 bm_word_t orig = dest_map[limit];
522 bm_word_t temp = merge_tail_of_map(orig | other_map[limit], orig, rest);
523 changed = changed || (temp != orig);
524 dest_map[limit] = temp;
525 }
526 return changed;
527 }
528
529 bool BitMap::set_difference_with_result(const BitMap& other) {
530 assert(size() == other.size(), "must have same size");
531 bool changed = false;
532 bm_word_t* dest_map = map();
533 const bm_word_t* other_map = other.map();
534 idx_t limit = to_words_align_down(size());
535 for (idx_t index = 0; index < limit; ++index) {
536 bm_word_t orig = dest_map[index];
537 bm_word_t temp = orig & ~other_map[index];
538 changed = changed || (temp != orig);
539 dest_map[index] = temp;
540 }
541 idx_t rest = bit_in_word(size());
542 if (rest > 0) {
543 bm_word_t orig = dest_map[limit];
544 bm_word_t temp = merge_tail_of_map(orig & ~other_map[limit], orig, rest);
545 changed = changed || (temp != orig);
546 dest_map[limit] = temp;
547 }
548 return changed;
549 }
550
551 bool BitMap::set_intersection_with_result(const BitMap& other) {
552 assert(size() == other.size(), "must have same size");
553 bool changed = false;
554 bm_word_t* dest_map = map();
555 const bm_word_t* other_map = other.map();
556 idx_t limit = to_words_align_down(size());
557 for (idx_t index = 0; index < limit; ++index) {
558 bm_word_t orig = dest_map[index];
559 bm_word_t temp = orig & other_map[index];
560 changed = changed || (temp != orig);
561 dest_map[index] = temp;
562 }
563 idx_t rest = bit_in_word(size());
564 if (rest > 0) {
565 bm_word_t orig = dest_map[limit];
566 bm_word_t temp = merge_tail_of_map(orig & other_map[limit], orig, rest);
567 changed = changed || (temp != orig);
568 dest_map[limit] = temp;
569 }
570 return changed;
571 }
572
573 void BitMap::set_from(const BitMap& other) {
574 assert(size() == other.size(), "must have same size");
575 bm_word_t* dest_map = map();
576 const bm_word_t* other_map = other.map();
577 idx_t copy_words = to_words_align_down(size());
578 Copy::disjoint_words((HeapWord*)other_map, (HeapWord*)dest_map, copy_words);
579 idx_t rest = bit_in_word(size());
580 if (rest > 0) {
581 dest_map[copy_words] = merge_tail_of_map(other_map[copy_words],
582 dest_map[copy_words],
583 rest);
584 }
585 }
586
587 bool BitMap::is_same(const BitMap& other) const {
588 assert(size() == other.size(), "must have same size");
589 const bm_word_t* dest_map = map();
590 const bm_word_t* other_map = other.map();
591 idx_t limit = to_words_align_down(size());
592 for (idx_t index = 0; index < limit; ++index) {
593 if (dest_map[index] != other_map[index]) return false;
594 }
595 idx_t rest = bit_in_word(size());
596 return (rest == 0) || (tail_of_map(dest_map[limit] ^ other_map[limit], rest) == 0);
597 }
598
599 bool BitMap::is_full() const {
600 const bm_word_t* words = map();
601 idx_t limit = to_words_align_down(size());
602 for (idx_t index = 0; index < limit; ++index) {
603 if (~words[index] != 0) return false;
604 }
605 idx_t rest = bit_in_word(size());
606 return (rest == 0) || (tail_of_map(~words[limit], rest) == 0);
607 }
608
609 bool BitMap::is_empty() const {
610 const bm_word_t* words = map();
611 idx_t limit = to_words_align_down(size());
612 for (idx_t index = 0; index < limit; ++index) {
613 if (words[index] != 0) return false;
614 }
615 idx_t rest = bit_in_word(size());
616 return (rest == 0) || (tail_of_map(words[limit], rest) == 0);
617 }
618
619 void BitMap::clear_large() {
620 clear_large_range_of_words(0, size_in_words());
621 }
622
623 // Note that if the closure itself modifies the bitmap
624 // then modifications in and to the left of the _bit_ being
625 // currently sampled will not be seen. Note also that the
626 // interval [leftOffset, rightOffset) is right open.
627 bool BitMap::iterate(BitMapClosure* blk, idx_t leftOffset, idx_t rightOffset) {
628 verify_range(leftOffset, rightOffset);
629
630 idx_t startIndex = to_words_align_down(leftOffset);
631 idx_t endIndex = to_words_align_up(rightOffset);
632 for (idx_t index = startIndex, offset = leftOffset;
633 offset < rightOffset && index < endIndex;
634 offset = (++index) << LogBitsPerWord) {
635 idx_t rest = map(index) >> (offset & (BitsPerWord - 1));
636 for (; offset < rightOffset && rest != 0; offset++) {
637 if (rest & 1) {
638 if (!blk->do_bit(offset)) return false;
639 // resample at each closure application
640 // (see, for instance, CMS bug 4525989)
641 rest = map(index) >> (offset & (BitsPerWord -1));
642 }
643 rest = rest >> 1;
644 }
645 }
646 return true;
647 }
648
649 const BitMap::idx_t* BitMap::_pop_count_table = NULL;
650
651 void BitMap::init_pop_count_table() {
652 if (_pop_count_table == NULL) {
653 BitMap::idx_t *table = NEW_C_HEAP_ARRAY(idx_t, 256, mtInternal);
654 for (uint i = 0; i < 256; i++) {
655 table[i] = num_set_bits(i);
656 }
657
658 if (!Atomic::replace_if_null(&_pop_count_table, table)) {
659 guarantee(_pop_count_table != NULL, "invariant");
660 FREE_C_HEAP_ARRAY(idx_t, table);
661 }
662 }
663 }
664
665 BitMap::idx_t BitMap::num_set_bits(bm_word_t w) {
666 idx_t bits = 0;
667
668 while (w != 0) {
669 while ((w & 1) == 0) {
670 w >>= 1;
671 }
672 bits++;
673 w >>= 1;
674 }
675 return bits;
676 }
677
678 BitMap::idx_t BitMap::num_set_bits_from_table(unsigned char c) {
679 assert(_pop_count_table != NULL, "precondition");
680 return _pop_count_table[c];
681 }
682
683 BitMap::idx_t BitMap::count_one_bits() const {
684 init_pop_count_table(); // If necessary.
685 idx_t sum = 0;
686 typedef unsigned char uchar;
687 for (idx_t i = 0; i < size_in_words(); i++) {
688 bm_word_t w = map()[i];
689 for (size_t j = 0; j < sizeof(bm_word_t); j++) {
690 sum += num_set_bits_from_table(uchar(w & 255));
691 w >>= 8;
692 }
693 }
694 return sum;
695 }
696
697 void BitMap::print_on_error(outputStream* st, const char* prefix) const {
698 st->print_cr("%s[" PTR_FORMAT ", " PTR_FORMAT ")",
699 prefix, p2i(map()), p2i((char*)map() + (size() >> LogBitsPerByte)));
700 }
701
702 void BitMap::write_to(bm_word_t* buffer, size_t buffer_size_in_bytes) const {
703 assert(buffer_size_in_bytes == size_in_bytes(), "must be");
704 memcpy(buffer, _map, size_in_bytes());
705 }
706
707 #ifndef PRODUCT
708
709 void BitMap::print_on(outputStream* st) const {
710 tty->print("Bitmap(" SIZE_FORMAT "):", size());
711 for (idx_t index = 0; index < size(); index++) {
712 tty->print("%c", at(index) ? '1' : '0');
713 }
714 tty->cr();
715 }
716
717 #endif