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