1 /*
2 * Copyright (c) 1997, 2009, 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 "incls/_precompiled.incl"
26 # include "incls/_bitMap.cpp.incl"
27
28
29 BitMap::BitMap(bm_word_t* map, idx_t size_in_bits) :
30 _map(map), _size(size_in_bits)
31 {
32 assert(sizeof(bm_word_t) == BytesPerWord, "Implementation assumption.");
33 assert(size_in_bits >= 0, "just checking");
34 }
35
36
37 BitMap::BitMap(idx_t size_in_bits, bool in_resource_area) :
38 _map(NULL), _size(0)
39 {
40 assert(sizeof(bm_word_t) == BytesPerWord, "Implementation assumption.");
41 resize(size_in_bits, in_resource_area);
42 }
43
44 void BitMap::resize(idx_t size_in_bits, bool in_resource_area) {
45 assert(size_in_bits >= 0, "just checking");
46 idx_t old_size_in_words = size_in_words();
47 bm_word_t* old_map = map();
48
49 _size = size_in_bits;
50 idx_t new_size_in_words = size_in_words();
51 if (in_resource_area) {
52 _map = NEW_RESOURCE_ARRAY(bm_word_t, new_size_in_words);
53 } else {
54 if (old_map != NULL) FREE_C_HEAP_ARRAY(bm_word_t, _map);
55 _map = NEW_C_HEAP_ARRAY(bm_word_t, new_size_in_words);
56 }
57 Copy::disjoint_words((HeapWord*)old_map, (HeapWord*) _map,
58 MIN2(old_size_in_words, new_size_in_words));
59 if (new_size_in_words > old_size_in_words) {
60 clear_range_of_words(old_size_in_words, size_in_words());
61 }
62 }
63
64 void BitMap::set_range_within_word(idx_t beg, idx_t end) {
65 // With a valid range (beg <= end), this test ensures that end != 0, as
66 // required by inverted_bit_mask_for_range. Also avoids an unnecessary write.
67 if (beg != end) {
68 bm_word_t mask = inverted_bit_mask_for_range(beg, end);
69 *word_addr(beg) |= ~mask;
70 }
71 }
72
73 void BitMap::clear_range_within_word(idx_t beg, idx_t end) {
74 // With a valid range (beg <= end), this test ensures that end != 0, as
75 // required by inverted_bit_mask_for_range. Also avoids an unnecessary write.
76 if (beg != end) {
77 bm_word_t mask = inverted_bit_mask_for_range(beg, end);
78 *word_addr(beg) &= mask;
79 }
80 }
81
82 void BitMap::par_put_range_within_word(idx_t beg, idx_t end, bool value) {
83 assert(value == 0 || value == 1, "0 for clear, 1 for set");
84 // With a valid range (beg <= end), this test ensures that end != 0, as
85 // required by inverted_bit_mask_for_range. Also avoids an unnecessary write.
86 if (beg != end) {
87 intptr_t* pw = (intptr_t*)word_addr(beg);
88 intptr_t w = *pw;
89 intptr_t mr = (intptr_t)inverted_bit_mask_for_range(beg, end);
90 intptr_t nw = value ? (w | ~mr) : (w & mr);
91 while (true) {
92 intptr_t res = Atomic::cmpxchg_ptr(nw, pw, w);
93 if (res == w) break;
94 w = *pw;
95 nw = value ? (w | ~mr) : (w & mr);
96 }
97 }
98 }
99
100 void BitMap::set_range(idx_t beg, idx_t end) {
101 verify_range(beg, end);
102
103 idx_t beg_full_word = word_index_round_up(beg);
104 idx_t end_full_word = word_index(end);
105
106 if (beg_full_word < end_full_word) {
107 // The range includes at least one full word.
108 set_range_within_word(beg, bit_index(beg_full_word));
109 set_range_of_words(beg_full_word, end_full_word);
110 set_range_within_word(bit_index(end_full_word), end);
111 } else {
112 // The range spans at most 2 partial words.
113 idx_t boundary = MIN2(bit_index(beg_full_word), end);
114 set_range_within_word(beg, boundary);
115 set_range_within_word(boundary, end);
116 }
117 }
118
119 void BitMap::clear_range(idx_t beg, idx_t end) {
120 verify_range(beg, end);
121
122 idx_t beg_full_word = word_index_round_up(beg);
123 idx_t end_full_word = word_index(end);
124
125 if (beg_full_word < end_full_word) {
126 // The range includes at least one full word.
127 clear_range_within_word(beg, bit_index(beg_full_word));
128 clear_range_of_words(beg_full_word, end_full_word);
129 clear_range_within_word(bit_index(end_full_word), end);
130 } else {
131 // The range spans at most 2 partial words.
132 idx_t boundary = MIN2(bit_index(beg_full_word), end);
133 clear_range_within_word(beg, boundary);
134 clear_range_within_word(boundary, end);
135 }
136 }
137
138 void BitMap::set_large_range(idx_t beg, idx_t end) {
139 verify_range(beg, end);
140
141 idx_t beg_full_word = word_index_round_up(beg);
142 idx_t end_full_word = word_index(end);
143
144 assert(end_full_word - beg_full_word >= 32,
145 "the range must include at least 32 bytes");
146
147 // The range includes at least one full word.
148 set_range_within_word(beg, bit_index(beg_full_word));
149 set_large_range_of_words(beg_full_word, end_full_word);
150 set_range_within_word(bit_index(end_full_word), end);
151 }
152
153 void BitMap::clear_large_range(idx_t beg, idx_t end) {
154 verify_range(beg, end);
155
156 idx_t beg_full_word = word_index_round_up(beg);
157 idx_t end_full_word = word_index(end);
158
159 assert(end_full_word - beg_full_word >= 32,
160 "the range must include at least 32 bytes");
161
162 // The range includes at least one full word.
163 clear_range_within_word(beg, bit_index(beg_full_word));
164 clear_large_range_of_words(beg_full_word, end_full_word);
165 clear_range_within_word(bit_index(end_full_word), end);
166 }
167
168 void BitMap::mostly_disjoint_range_union(BitMap* from_bitmap,
169 idx_t from_start_index,
170 idx_t to_start_index,
171 size_t word_num) {
172 // Ensure that the parameters are correct.
173 // These shouldn't be that expensive to check, hence I left them as
174 // guarantees.
175 guarantee(from_bitmap->bit_in_word(from_start_index) == 0,
176 "it should be aligned on a word boundary");
177 guarantee(bit_in_word(to_start_index) == 0,
178 "it should be aligned on a word boundary");
179 guarantee(word_num >= 2, "word_num should be at least 2");
180
181 intptr_t* from = (intptr_t*) from_bitmap->word_addr(from_start_index);
182 intptr_t* to = (intptr_t*) word_addr(to_start_index);
183
184 if (*from != 0) {
185 // if it's 0, then there's no point in doing the CAS
186 while (true) {
187 intptr_t old_value = *to;
188 intptr_t new_value = old_value | *from;
189 intptr_t res = Atomic::cmpxchg_ptr(new_value, to, old_value);
190 if (res == old_value) break;
191 }
192 }
193 ++from;
194 ++to;
195
196 for (size_t i = 0; i < word_num - 2; ++i) {
197 if (*from != 0) {
198 // if it's 0, then there's no point in doing the CAS
199 assert(*to == 0, "nobody else should be writing here");
200 intptr_t new_value = *from;
201 *to = new_value;
202 }
203
204 ++from;
205 ++to;
206 }
207
208 if (*from != 0) {
209 // if it's 0, then there's no point in doing the CAS
210 while (true) {
211 intptr_t old_value = *to;
212 intptr_t new_value = old_value | *from;
213 intptr_t res = Atomic::cmpxchg_ptr(new_value, to, old_value);
214 if (res == old_value) break;
215 }
216 }
217
218 // the -1 is because we didn't advance them after the final CAS
219 assert(from ==
220 (intptr_t*) from_bitmap->word_addr(from_start_index) + word_num - 1,
221 "invariant");
222 assert(to == (intptr_t*) word_addr(to_start_index) + word_num - 1,
223 "invariant");
224 }
225
226 void BitMap::at_put(idx_t offset, bool value) {
227 if (value) {
228 set_bit(offset);
229 } else {
230 clear_bit(offset);
231 }
232 }
233
234 // Return true to indicate that this thread changed
235 // the bit, false to indicate that someone else did.
236 // In either case, the requested bit is in the
237 // requested state some time during the period that
238 // this thread is executing this call. More importantly,
239 // if no other thread is executing an action to
240 // change the requested bit to a state other than
241 // the one that this thread is trying to set it to,
242 // then the the bit is in the expected state
243 // at exit from this method. However, rather than
244 // make such a strong assertion here, based on
245 // assuming such constrained use (which though true
246 // today, could change in the future to service some
247 // funky parallel algorithm), we encourage callers
248 // to do such verification, as and when appropriate.
249 bool BitMap::par_at_put(idx_t bit, bool value) {
250 return value ? par_set_bit(bit) : par_clear_bit(bit);
251 }
252
253 void BitMap::at_put_grow(idx_t offset, bool value) {
254 if (offset >= size()) {
255 resize(2 * MAX2(size(), offset));
256 }
257 at_put(offset, value);
258 }
259
260 void BitMap::at_put_range(idx_t start_offset, idx_t end_offset, bool value) {
261 if (value) {
262 set_range(start_offset, end_offset);
263 } else {
264 clear_range(start_offset, end_offset);
265 }
266 }
267
268 void BitMap::par_at_put_range(idx_t beg, idx_t end, bool value) {
269 verify_range(beg, end);
270
271 idx_t beg_full_word = word_index_round_up(beg);
272 idx_t end_full_word = word_index(end);
273
274 if (beg_full_word < end_full_word) {
275 // The range includes at least one full word.
276 par_put_range_within_word(beg, bit_index(beg_full_word), value);
277 if (value) {
278 set_range_of_words(beg_full_word, end_full_word);
279 } else {
280 clear_range_of_words(beg_full_word, end_full_word);
281 }
282 par_put_range_within_word(bit_index(end_full_word), end, value);
283 } else {
284 // The range spans at most 2 partial words.
285 idx_t boundary = MIN2(bit_index(beg_full_word), end);
286 par_put_range_within_word(beg, boundary, value);
287 par_put_range_within_word(boundary, end, value);
288 }
289
290 }
291
292 void BitMap::at_put_large_range(idx_t beg, idx_t end, bool value) {
293 if (value) {
294 set_large_range(beg, end);
295 } else {
296 clear_large_range(beg, end);
297 }
298 }
299
300 void BitMap::par_at_put_large_range(idx_t beg, idx_t end, bool value) {
301 verify_range(beg, end);
302
303 idx_t beg_full_word = word_index_round_up(beg);
304 idx_t end_full_word = word_index(end);
305
306 assert(end_full_word - beg_full_word >= 32,
307 "the range must include at least 32 bytes");
308
309 // The range includes at least one full word.
310 par_put_range_within_word(beg, bit_index(beg_full_word), value);
311 if (value) {
312 set_large_range_of_words(beg_full_word, end_full_word);
313 } else {
314 clear_large_range_of_words(beg_full_word, end_full_word);
315 }
316 par_put_range_within_word(bit_index(end_full_word), end, value);
317 }
318
319 bool BitMap::contains(const BitMap other) const {
320 assert(size() == other.size(), "must have same size");
321 bm_word_t* dest_map = map();
322 bm_word_t* other_map = other.map();
323 idx_t size = size_in_words();
324 for (idx_t index = 0; index < size_in_words(); index++) {
325 bm_word_t word_union = dest_map[index] | other_map[index];
326 // If this has more bits set than dest_map[index], then other is not a
327 // subset.
328 if (word_union != dest_map[index]) return false;
329 }
330 return true;
331 }
332
333 bool BitMap::intersects(const BitMap other) const {
334 assert(size() == other.size(), "must have same size");
335 bm_word_t* dest_map = map();
336 bm_word_t* other_map = other.map();
337 idx_t size = size_in_words();
338 for (idx_t index = 0; index < size_in_words(); index++) {
339 if ((dest_map[index] & other_map[index]) != 0) return true;
340 }
341 // Otherwise, no intersection.
342 return false;
343 }
344
345 void BitMap::set_union(BitMap other) {
346 assert(size() == other.size(), "must have same size");
347 bm_word_t* dest_map = map();
348 bm_word_t* other_map = other.map();
349 idx_t size = size_in_words();
350 for (idx_t index = 0; index < size_in_words(); index++) {
351 dest_map[index] = dest_map[index] | other_map[index];
352 }
353 }
354
355
356 void BitMap::set_difference(BitMap other) {
357 assert(size() == other.size(), "must have same size");
358 bm_word_t* dest_map = map();
359 bm_word_t* other_map = other.map();
360 idx_t size = size_in_words();
361 for (idx_t index = 0; index < size_in_words(); index++) {
362 dest_map[index] = dest_map[index] & ~(other_map[index]);
363 }
364 }
365
366
367 void BitMap::set_intersection(BitMap other) {
368 assert(size() == other.size(), "must have same size");
369 bm_word_t* dest_map = map();
370 bm_word_t* other_map = other.map();
371 idx_t size = size_in_words();
372 for (idx_t index = 0; index < size; index++) {
373 dest_map[index] = dest_map[index] & other_map[index];
374 }
375 }
376
377
378 void BitMap::set_intersection_at_offset(BitMap other, idx_t offset) {
379 assert(other.size() >= offset, "offset not in range");
380 assert(other.size() - offset >= size(), "other not large enough");
381 // XXX Ideally, we would remove this restriction.
382 guarantee((offset % (sizeof(bm_word_t) * BitsPerByte)) == 0,
383 "Only handle aligned cases so far.");
384 bm_word_t* dest_map = map();
385 bm_word_t* other_map = other.map();
386 idx_t offset_word_ind = word_index(offset);
387 idx_t size = size_in_words();
388 for (idx_t index = 0; index < size; index++) {
389 dest_map[index] = dest_map[index] & other_map[offset_word_ind + index];
390 }
391 }
392
393 bool BitMap::set_union_with_result(BitMap other) {
394 assert(size() == other.size(), "must have same size");
395 bool changed = false;
396 bm_word_t* dest_map = map();
397 bm_word_t* other_map = other.map();
398 idx_t size = size_in_words();
399 for (idx_t index = 0; index < size; index++) {
400 idx_t temp = map(index) | other_map[index];
401 changed = changed || (temp != map(index));
402 map()[index] = temp;
403 }
404 return changed;
405 }
406
407
408 bool BitMap::set_difference_with_result(BitMap other) {
409 assert(size() == other.size(), "must have same size");
410 bool changed = false;
411 bm_word_t* dest_map = map();
412 bm_word_t* other_map = other.map();
413 idx_t size = size_in_words();
414 for (idx_t index = 0; index < size; index++) {
415 bm_word_t temp = dest_map[index] & ~(other_map[index]);
416 changed = changed || (temp != dest_map[index]);
417 dest_map[index] = temp;
418 }
419 return changed;
420 }
421
422
423 bool BitMap::set_intersection_with_result(BitMap other) {
424 assert(size() == other.size(), "must have same size");
425 bool changed = false;
426 bm_word_t* dest_map = map();
427 bm_word_t* other_map = other.map();
428 idx_t size = size_in_words();
429 for (idx_t index = 0; index < size; index++) {
430 bm_word_t orig = dest_map[index];
431 bm_word_t temp = orig & other_map[index];
432 changed = changed || (temp != orig);
433 dest_map[index] = temp;
434 }
435 return changed;
436 }
437
438
439 void BitMap::set_from(BitMap other) {
440 assert(size() == other.size(), "must have same size");
441 bm_word_t* dest_map = map();
442 bm_word_t* other_map = other.map();
443 idx_t size = size_in_words();
444 for (idx_t index = 0; index < size; index++) {
445 dest_map[index] = other_map[index];
446 }
447 }
448
449
450 bool BitMap::is_same(BitMap other) {
451 assert(size() == other.size(), "must have same size");
452 bm_word_t* dest_map = map();
453 bm_word_t* other_map = other.map();
454 idx_t size = size_in_words();
455 for (idx_t index = 0; index < size; index++) {
456 if (dest_map[index] != other_map[index]) return false;
457 }
458 return true;
459 }
460
461 bool BitMap::is_full() const {
462 bm_word_t* word = map();
463 idx_t rest = size();
464 for (; rest >= (idx_t) BitsPerWord; rest -= BitsPerWord) {
465 if (*word != (bm_word_t) AllBits) return false;
466 word++;
467 }
468 return rest == 0 || (*word | ~right_n_bits((int)rest)) == (bm_word_t) AllBits;
469 }
470
471
472 bool BitMap::is_empty() const {
473 bm_word_t* word = map();
474 idx_t rest = size();
475 for (; rest >= (idx_t) BitsPerWord; rest -= BitsPerWord) {
476 if (*word != (bm_word_t) NoBits) return false;
477 word++;
478 }
479 return rest == 0 || (*word & right_n_bits((int)rest)) == (bm_word_t) NoBits;
480 }
481
482 void BitMap::clear_large() {
483 clear_large_range_of_words(0, size_in_words());
484 }
485
486 // Note that if the closure itself modifies the bitmap
487 // then modifications in and to the left of the _bit_ being
488 // currently sampled will not be seen. Note also that the
489 // interval [leftOffset, rightOffset) is right open.
490 bool BitMap::iterate(BitMapClosure* blk, idx_t leftOffset, idx_t rightOffset) {
491 verify_range(leftOffset, rightOffset);
492
493 idx_t startIndex = word_index(leftOffset);
494 idx_t endIndex = MIN2(word_index(rightOffset) + 1, size_in_words());
495 for (idx_t index = startIndex, offset = leftOffset;
496 offset < rightOffset && index < endIndex;
497 offset = (++index) << LogBitsPerWord) {
498 idx_t rest = map(index) >> (offset & (BitsPerWord - 1));
499 for (; offset < rightOffset && rest != (bm_word_t)NoBits; offset++) {
500 if (rest & 1) {
501 if (!blk->do_bit(offset)) return false;
502 // resample at each closure application
503 // (see, for instance, CMS bug 4525989)
504 rest = map(index) >> (offset & (BitsPerWord -1));
505 }
506 rest = rest >> 1;
507 }
508 }
509 return true;
510 }
511
512 BitMap::idx_t* BitMap::_pop_count_table = NULL;
513
514 void BitMap::init_pop_count_table() {
515 if (_pop_count_table == NULL) {
516 BitMap::idx_t *table = NEW_C_HEAP_ARRAY(idx_t, 256);
517 for (uint i = 0; i < 256; i++) {
518 table[i] = num_set_bits(i);
519 }
520
521 intptr_t res = Atomic::cmpxchg_ptr((intptr_t) table,
522 (intptr_t*) &_pop_count_table,
523 (intptr_t) NULL_WORD);
524 if (res != NULL_WORD) {
525 guarantee( _pop_count_table == (void*) res, "invariant" );
526 FREE_C_HEAP_ARRAY(bm_word_t, table);
527 }
528 }
529 }
530
531 BitMap::idx_t BitMap::num_set_bits(bm_word_t w) {
532 idx_t bits = 0;
533
534 while (w != 0) {
535 while ((w & 1) == 0) {
536 w >>= 1;
537 }
538 bits++;
539 w >>= 1;
540 }
541 return bits;
542 }
543
544 BitMap::idx_t BitMap::num_set_bits_from_table(unsigned char c) {
545 assert(_pop_count_table != NULL, "precondition");
546 return _pop_count_table[c];
547 }
548
549 BitMap::idx_t BitMap::count_one_bits() const {
550 init_pop_count_table(); // If necessary.
551 idx_t sum = 0;
552 typedef unsigned char uchar;
553 for (idx_t i = 0; i < size_in_words(); i++) {
554 bm_word_t w = map()[i];
555 for (size_t j = 0; j < sizeof(bm_word_t); j++) {
556 sum += num_set_bits_from_table(uchar(w & 255));
557 w >>= 8;
558 }
559 }
560 return sum;
561 }
562
563
564 #ifndef PRODUCT
565
566 void BitMap::print_on(outputStream* st) const {
567 tty->print("Bitmap(%d):", size());
568 for (idx_t index = 0; index < size(); index++) {
569 tty->print("%c", at(index) ? '1' : '0');
570 }
571 tty->cr();
572 }
573
574 #endif
575
576
577 BitMap2D::BitMap2D(bm_word_t* map, idx_t size_in_slots, idx_t bits_per_slot)
578 : _bits_per_slot(bits_per_slot)
579 , _map(map, size_in_slots * bits_per_slot)
580 {
581 }
582
583
584 BitMap2D::BitMap2D(idx_t size_in_slots, idx_t bits_per_slot)
585 : _bits_per_slot(bits_per_slot)
586 , _map(size_in_slots * bits_per_slot)
587 {
588 }