1 /*
2 * Copyright (c) 1997, 2010, 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 "utilities/bitMap.inline.hpp"
28 #include "utilities/copy.hpp"
29 #ifdef TARGET_OS_FAMILY_linux
30 # include "os_linux.inline.hpp"
31 #endif
32 #ifdef TARGET_OS_FAMILY_solaris
33 # include "os_solaris.inline.hpp"
34 #endif
35 #ifdef TARGET_OS_FAMILY_windows
36 # include "os_windows.inline.hpp"
37 #endif
38 #ifdef TARGET_OS_FAMILY_bsd
39 # include "os_bsd.inline.hpp"
40 #endif
41
42
43 BitMap::BitMap(bm_word_t* map, idx_t size_in_bits) :
44 _map(map), _size(size_in_bits)
45 {
46 assert(sizeof(bm_word_t) == BytesPerWord, "Implementation assumption.");
47 assert(size_in_bits >= 0, "just checking");
48 }
49
50
51 BitMap::BitMap(idx_t size_in_bits, bool in_resource_area) :
52 _map(NULL), _size(0)
53 {
54 assert(sizeof(bm_word_t) == BytesPerWord, "Implementation assumption.");
55 resize(size_in_bits, in_resource_area);
56 }
57
58 void BitMap::resize(idx_t size_in_bits, bool in_resource_area) {
59 assert(size_in_bits >= 0, "just checking");
60 idx_t old_size_in_words = size_in_words();
61 bm_word_t* old_map = map();
62
63 _size = size_in_bits;
64 idx_t new_size_in_words = size_in_words();
65 if (in_resource_area) {
66 _map = NEW_RESOURCE_ARRAY(bm_word_t, new_size_in_words);
67 } else {
68 if (old_map != NULL) FREE_C_HEAP_ARRAY(bm_word_t, _map);
69 _map = NEW_C_HEAP_ARRAY(bm_word_t, new_size_in_words);
70 }
71 Copy::disjoint_words((HeapWord*)old_map, (HeapWord*) _map,
72 MIN2(old_size_in_words, new_size_in_words));
73 if (new_size_in_words > old_size_in_words) {
74 clear_range_of_words(old_size_in_words, size_in_words());
75 }
76 }
77
78 void BitMap::set_range_within_word(idx_t beg, idx_t end) {
79 // With a valid range (beg <= end), this test ensures that end != 0, as
80 // required by inverted_bit_mask_for_range. Also avoids an unnecessary write.
81 if (beg != end) {
82 bm_word_t mask = inverted_bit_mask_for_range(beg, end);
83 *word_addr(beg) |= ~mask;
84 }
85 }
86
87 void BitMap::clear_range_within_word(idx_t beg, idx_t end) {
88 // With a valid range (beg <= end), this test ensures that end != 0, as
89 // required by inverted_bit_mask_for_range. Also avoids an unnecessary write.
90 if (beg != end) {
91 bm_word_t mask = inverted_bit_mask_for_range(beg, end);
92 *word_addr(beg) &= mask;
93 }
94 }
95
96 void BitMap::par_put_range_within_word(idx_t beg, idx_t end, bool value) {
97 assert(value == 0 || value == 1, "0 for clear, 1 for set");
98 // With a valid range (beg <= end), this test ensures that end != 0, as
99 // required by inverted_bit_mask_for_range. Also avoids an unnecessary write.
100 if (beg != end) {
101 intptr_t* pw = (intptr_t*)word_addr(beg);
102 intptr_t w = *pw;
103 intptr_t mr = (intptr_t)inverted_bit_mask_for_range(beg, end);
104 intptr_t nw = value ? (w | ~mr) : (w & mr);
105 while (true) {
106 intptr_t res = Atomic::cmpxchg_ptr(nw, pw, w);
107 if (res == w) break;
108 w = *pw;
109 nw = value ? (w | ~mr) : (w & mr);
110 }
111 }
112 }
113
114 void BitMap::set_range(idx_t beg, idx_t end) {
115 verify_range(beg, end);
116
117 idx_t beg_full_word = word_index_round_up(beg);
118 idx_t end_full_word = word_index(end);
119
120 if (beg_full_word < end_full_word) {
121 // The range includes at least one full word.
122 set_range_within_word(beg, bit_index(beg_full_word));
123 set_range_of_words(beg_full_word, end_full_word);
124 set_range_within_word(bit_index(end_full_word), end);
125 } else {
126 // The range spans at most 2 partial words.
127 idx_t boundary = MIN2(bit_index(beg_full_word), end);
128 set_range_within_word(beg, boundary);
129 set_range_within_word(boundary, end);
130 }
131 }
132
133 void BitMap::clear_range(idx_t beg, idx_t end) {
134 verify_range(beg, end);
135
136 idx_t beg_full_word = word_index_round_up(beg);
137 idx_t end_full_word = word_index(end);
138
139 if (beg_full_word < end_full_word) {
140 // The range includes at least one full word.
141 clear_range_within_word(beg, bit_index(beg_full_word));
142 clear_range_of_words(beg_full_word, end_full_word);
143 clear_range_within_word(bit_index(end_full_word), end);
144 } else {
145 // The range spans at most 2 partial words.
146 idx_t boundary = MIN2(bit_index(beg_full_word), end);
147 clear_range_within_word(beg, boundary);
148 clear_range_within_word(boundary, end);
149 }
150 }
151
152 void BitMap::set_large_range(idx_t beg, idx_t end) {
153 verify_range(beg, end);
154
155 idx_t beg_full_word = word_index_round_up(beg);
156 idx_t end_full_word = word_index(end);
157
158 assert(end_full_word - beg_full_word >= 32,
159 "the range must include at least 32 bytes");
160
161 // The range includes at least one full word.
162 set_range_within_word(beg, bit_index(beg_full_word));
163 set_large_range_of_words(beg_full_word, end_full_word);
164 set_range_within_word(bit_index(end_full_word), end);
165 }
166
167 void BitMap::clear_large_range(idx_t beg, idx_t end) {
168 verify_range(beg, end);
169
170 idx_t beg_full_word = word_index_round_up(beg);
171 idx_t end_full_word = word_index(end);
172
173 assert(end_full_word - beg_full_word >= 32,
174 "the range must include at least 32 bytes");
175
176 // The range includes at least one full word.
177 clear_range_within_word(beg, bit_index(beg_full_word));
178 clear_large_range_of_words(beg_full_word, end_full_word);
179 clear_range_within_word(bit_index(end_full_word), end);
180 }
181
182 void BitMap::mostly_disjoint_range_union(BitMap* from_bitmap,
183 idx_t from_start_index,
184 idx_t to_start_index,
185 size_t word_num) {
186 // Ensure that the parameters are correct.
187 // These shouldn't be that expensive to check, hence I left them as
188 // guarantees.
189 guarantee(from_bitmap->bit_in_word(from_start_index) == 0,
190 "it should be aligned on a word boundary");
191 guarantee(bit_in_word(to_start_index) == 0,
192 "it should be aligned on a word boundary");
193 guarantee(word_num >= 2, "word_num should be at least 2");
194
195 intptr_t* from = (intptr_t*) from_bitmap->word_addr(from_start_index);
196 intptr_t* to = (intptr_t*) word_addr(to_start_index);
197
198 if (*from != 0) {
199 // if it's 0, then there's no point in doing the CAS
200 while (true) {
201 intptr_t old_value = *to;
202 intptr_t new_value = old_value | *from;
203 intptr_t res = Atomic::cmpxchg_ptr(new_value, to, old_value);
204 if (res == old_value) break;
205 }
206 }
207 ++from;
208 ++to;
209
210 for (size_t i = 0; i < word_num - 2; ++i) {
211 if (*from != 0) {
212 // if it's 0, then there's no point in doing the CAS
213 assert(*to == 0, "nobody else should be writing here");
214 intptr_t new_value = *from;
215 *to = new_value;
216 }
217
218 ++from;
219 ++to;
220 }
221
222 if (*from != 0) {
223 // if it's 0, then there's no point in doing the CAS
224 while (true) {
225 intptr_t old_value = *to;
226 intptr_t new_value = old_value | *from;
227 intptr_t res = Atomic::cmpxchg_ptr(new_value, to, old_value);
228 if (res == old_value) break;
229 }
230 }
231
232 // the -1 is because we didn't advance them after the final CAS
233 assert(from ==
234 (intptr_t*) from_bitmap->word_addr(from_start_index) + word_num - 1,
235 "invariant");
236 assert(to == (intptr_t*) word_addr(to_start_index) + word_num - 1,
237 "invariant");
238 }
239
240 void BitMap::at_put(idx_t offset, bool value) {
241 if (value) {
242 set_bit(offset);
243 } else {
244 clear_bit(offset);
245 }
246 }
247
248 // Return true to indicate that this thread changed
249 // the bit, false to indicate that someone else did.
250 // In either case, the requested bit is in the
251 // requested state some time during the period that
252 // this thread is executing this call. More importantly,
253 // if no other thread is executing an action to
254 // change the requested bit to a state other than
255 // the one that this thread is trying to set it to,
256 // then the the bit is in the expected state
257 // at exit from this method. However, rather than
258 // make such a strong assertion here, based on
259 // assuming such constrained use (which though true
260 // today, could change in the future to service some
261 // funky parallel algorithm), we encourage callers
262 // to do such verification, as and when appropriate.
263 bool BitMap::par_at_put(idx_t bit, bool value) {
264 return value ? par_set_bit(bit) : par_clear_bit(bit);
265 }
266
267 void BitMap::at_put_grow(idx_t offset, bool value) {
268 if (offset >= size()) {
269 resize(2 * MAX2(size(), offset));
270 }
271 at_put(offset, value);
272 }
273
274 void BitMap::at_put_range(idx_t start_offset, idx_t end_offset, bool value) {
275 if (value) {
276 set_range(start_offset, end_offset);
277 } else {
278 clear_range(start_offset, end_offset);
279 }
280 }
281
282 void BitMap::par_at_put_range(idx_t beg, idx_t end, bool value) {
283 verify_range(beg, end);
284
285 idx_t beg_full_word = word_index_round_up(beg);
286 idx_t end_full_word = word_index(end);
287
288 if (beg_full_word < end_full_word) {
289 // The range includes at least one full word.
290 par_put_range_within_word(beg, bit_index(beg_full_word), value);
291 if (value) {
292 set_range_of_words(beg_full_word, end_full_word);
293 } else {
294 clear_range_of_words(beg_full_word, end_full_word);
295 }
296 par_put_range_within_word(bit_index(end_full_word), end, value);
297 } else {
298 // The range spans at most 2 partial words.
299 idx_t boundary = MIN2(bit_index(beg_full_word), end);
300 par_put_range_within_word(beg, boundary, value);
301 par_put_range_within_word(boundary, end, value);
302 }
303
304 }
305
306 void BitMap::at_put_large_range(idx_t beg, idx_t end, bool value) {
307 if (value) {
308 set_large_range(beg, end);
309 } else {
310 clear_large_range(beg, end);
311 }
312 }
313
314 void BitMap::par_at_put_large_range(idx_t beg, idx_t end, bool value) {
315 verify_range(beg, end);
316
317 idx_t beg_full_word = word_index_round_up(beg);
318 idx_t end_full_word = word_index(end);
319
320 assert(end_full_word - beg_full_word >= 32,
321 "the range must include at least 32 bytes");
322
323 // The range includes at least one full word.
324 par_put_range_within_word(beg, bit_index(beg_full_word), value);
325 if (value) {
326 set_large_range_of_words(beg_full_word, end_full_word);
327 } else {
328 clear_large_range_of_words(beg_full_word, end_full_word);
329 }
330 par_put_range_within_word(bit_index(end_full_word), end, value);
331 }
332
333 bool BitMap::contains(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 bm_word_t word_union = dest_map[index] | other_map[index];
340 // If this has more bits set than dest_map[index], then other is not a
341 // subset.
342 if (word_union != dest_map[index]) return false;
343 }
344 return true;
345 }
346
347 bool BitMap::intersects(const BitMap other) const {
348 assert(size() == other.size(), "must have same size");
349 bm_word_t* dest_map = map();
350 bm_word_t* other_map = other.map();
351 idx_t size = size_in_words();
352 for (idx_t index = 0; index < size_in_words(); index++) {
353 if ((dest_map[index] & other_map[index]) != 0) return true;
354 }
355 // Otherwise, no intersection.
356 return false;
357 }
358
359 void BitMap::set_union(BitMap other) {
360 assert(size() == other.size(), "must have same size");
361 bm_word_t* dest_map = map();
362 bm_word_t* other_map = other.map();
363 idx_t size = size_in_words();
364 for (idx_t index = 0; index < size_in_words(); index++) {
365 dest_map[index] = dest_map[index] | other_map[index];
366 }
367 }
368
369
370 void BitMap::set_difference(BitMap other) {
371 assert(size() == other.size(), "must have same size");
372 bm_word_t* dest_map = map();
373 bm_word_t* other_map = other.map();
374 idx_t size = size_in_words();
375 for (idx_t index = 0; index < size_in_words(); index++) {
376 dest_map[index] = dest_map[index] & ~(other_map[index]);
377 }
378 }
379
380
381 void BitMap::set_intersection(BitMap other) {
382 assert(size() == other.size(), "must have same size");
383 bm_word_t* dest_map = map();
384 bm_word_t* other_map = other.map();
385 idx_t size = size_in_words();
386 for (idx_t index = 0; index < size; index++) {
387 dest_map[index] = dest_map[index] & other_map[index];
388 }
389 }
390
391
392 void BitMap::set_intersection_at_offset(BitMap other, idx_t offset) {
393 assert(other.size() >= offset, "offset not in range");
394 assert(other.size() - offset >= size(), "other not large enough");
395 // XXX Ideally, we would remove this restriction.
396 guarantee((offset % (sizeof(bm_word_t) * BitsPerByte)) == 0,
397 "Only handle aligned cases so far.");
398 bm_word_t* dest_map = map();
399 bm_word_t* other_map = other.map();
400 idx_t offset_word_ind = word_index(offset);
401 idx_t size = size_in_words();
402 for (idx_t index = 0; index < size; index++) {
403 dest_map[index] = dest_map[index] & other_map[offset_word_ind + index];
404 }
405 }
406
407 bool BitMap::set_union_with_result(BitMap other) {
408 assert(size() == other.size(), "must have same size");
409 bool changed = false;
410 bm_word_t* dest_map = map();
411 bm_word_t* other_map = other.map();
412 idx_t size = size_in_words();
413 for (idx_t index = 0; index < size; index++) {
414 idx_t temp = map(index) | other_map[index];
415 changed = changed || (temp != map(index));
416 map()[index] = temp;
417 }
418 return changed;
419 }
420
421
422 bool BitMap::set_difference_with_result(BitMap other) {
423 assert(size() == other.size(), "must have same size");
424 bool changed = false;
425 bm_word_t* dest_map = map();
426 bm_word_t* other_map = other.map();
427 idx_t size = size_in_words();
428 for (idx_t index = 0; index < size; index++) {
429 bm_word_t temp = dest_map[index] & ~(other_map[index]);
430 changed = changed || (temp != dest_map[index]);
431 dest_map[index] = temp;
432 }
433 return changed;
434 }
435
436
437 bool BitMap::set_intersection_with_result(BitMap other) {
438 assert(size() == other.size(), "must have same size");
439 bool changed = false;
440 bm_word_t* dest_map = map();
441 bm_word_t* other_map = other.map();
442 idx_t size = size_in_words();
443 for (idx_t index = 0; index < size; index++) {
444 bm_word_t orig = dest_map[index];
445 bm_word_t temp = orig & other_map[index];
446 changed = changed || (temp != orig);
447 dest_map[index] = temp;
448 }
449 return changed;
450 }
451
452
453 void BitMap::set_from(BitMap other) {
454 assert(size() == other.size(), "must have same size");
455 bm_word_t* dest_map = map();
456 bm_word_t* other_map = other.map();
457 idx_t size = size_in_words();
458 for (idx_t index = 0; index < size; index++) {
459 dest_map[index] = other_map[index];
460 }
461 }
462
463
464 bool BitMap::is_same(BitMap other) {
465 assert(size() == other.size(), "must have same size");
466 bm_word_t* dest_map = map();
467 bm_word_t* other_map = other.map();
468 idx_t size = size_in_words();
469 for (idx_t index = 0; index < size; index++) {
470 if (dest_map[index] != other_map[index]) return false;
471 }
472 return true;
473 }
474
475 bool BitMap::is_full() const {
476 bm_word_t* word = map();
477 idx_t rest = size();
478 for (; rest >= (idx_t) BitsPerWord; rest -= BitsPerWord) {
479 if (*word != (bm_word_t) AllBits) return false;
480 word++;
481 }
482 return rest == 0 || (*word | ~right_n_bits((int)rest)) == (bm_word_t) AllBits;
483 }
484
485
486 bool BitMap::is_empty() const {
487 bm_word_t* word = map();
488 idx_t rest = size();
489 for (; rest >= (idx_t) BitsPerWord; rest -= BitsPerWord) {
490 if (*word != (bm_word_t) NoBits) return false;
491 word++;
492 }
493 return rest == 0 || (*word & right_n_bits((int)rest)) == (bm_word_t) NoBits;
494 }
495
496 void BitMap::clear_large() {
497 clear_large_range_of_words(0, size_in_words());
498 }
499
500 // Note that if the closure itself modifies the bitmap
501 // then modifications in and to the left of the _bit_ being
502 // currently sampled will not be seen. Note also that the
503 // interval [leftOffset, rightOffset) is right open.
504 bool BitMap::iterate(BitMapClosure* blk, idx_t leftOffset, idx_t rightOffset) {
505 verify_range(leftOffset, rightOffset);
506
507 idx_t startIndex = word_index(leftOffset);
508 idx_t endIndex = MIN2(word_index(rightOffset) + 1, size_in_words());
509 for (idx_t index = startIndex, offset = leftOffset;
510 offset < rightOffset && index < endIndex;
511 offset = (++index) << LogBitsPerWord) {
512 idx_t rest = map(index) >> (offset & (BitsPerWord - 1));
513 for (; offset < rightOffset && rest != (bm_word_t)NoBits; offset++) {
514 if (rest & 1) {
515 if (!blk->do_bit(offset)) return false;
516 // resample at each closure application
517 // (see, for instance, CMS bug 4525989)
518 rest = map(index) >> (offset & (BitsPerWord -1));
519 }
520 rest = rest >> 1;
521 }
522 }
523 return true;
524 }
525
526 BitMap::idx_t* BitMap::_pop_count_table = NULL;
527
528 void BitMap::init_pop_count_table() {
529 if (_pop_count_table == NULL) {
530 BitMap::idx_t *table = NEW_C_HEAP_ARRAY(idx_t, 256);
531 for (uint i = 0; i < 256; i++) {
532 table[i] = num_set_bits(i);
533 }
534
535 intptr_t res = Atomic::cmpxchg_ptr((intptr_t) table,
536 (intptr_t*) &_pop_count_table,
537 (intptr_t) NULL_WORD);
538 if (res != NULL_WORD) {
539 guarantee( _pop_count_table == (void*) res, "invariant" );
540 FREE_C_HEAP_ARRAY(bm_word_t, table);
541 }
542 }
543 }
544
545 BitMap::idx_t BitMap::num_set_bits(bm_word_t w) {
546 idx_t bits = 0;
547
548 while (w != 0) {
549 while ((w & 1) == 0) {
550 w >>= 1;
551 }
552 bits++;
553 w >>= 1;
554 }
555 return bits;
556 }
557
558 BitMap::idx_t BitMap::num_set_bits_from_table(unsigned char c) {
559 assert(_pop_count_table != NULL, "precondition");
560 return _pop_count_table[c];
561 }
562
563 BitMap::idx_t BitMap::count_one_bits() const {
564 init_pop_count_table(); // If necessary.
565 idx_t sum = 0;
566 typedef unsigned char uchar;
567 for (idx_t i = 0; i < size_in_words(); i++) {
568 bm_word_t w = map()[i];
569 for (size_t j = 0; j < sizeof(bm_word_t); j++) {
570 sum += num_set_bits_from_table(uchar(w & 255));
571 w >>= 8;
572 }
573 }
574 return sum;
575 }
576
577
578 #ifndef PRODUCT
579
580 void BitMap::print_on(outputStream* st) const {
581 tty->print("Bitmap(%d):", size());
582 for (idx_t index = 0; index < size(); index++) {
583 tty->print("%c", at(index) ? '1' : '0');
584 }
585 tty->cr();
586 }
587
588 #endif
589
590
591 BitMap2D::BitMap2D(bm_word_t* map, idx_t size_in_slots, idx_t bits_per_slot)
592 : _bits_per_slot(bits_per_slot)
593 , _map(map, size_in_slots * bits_per_slot)
594 {
595 }
596
597
598 BitMap2D::BitMap2D(idx_t size_in_slots, idx_t bits_per_slot)
599 : _bits_per_slot(bits_per_slot)
600 , _map(size_in_slots * bits_per_slot)
601 {
602 }