1 /*
2 * Copyright (c) 1997, 2015, 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.inline.hpp"
29 #include "utilities/bitMap.inline.hpp"
30 #include "utilities/copy.hpp"
31
32 STATIC_ASSERT(sizeof(BitMap::bm_word_t) == BytesPerWord); // "Implementation assumption."
33
34 BitMap::BitMap(idx_t size_in_bits, bool in_resource_area) :
35 _map(NULL), _size(0)
36 {
37 resize(size_in_bits, in_resource_area);
38 }
39
40 #ifdef ASSERT
41 void BitMap::verify_index(idx_t index) const {
42 assert(index < _size, "BitMap index out of bounds");
43 }
44
45 void BitMap::verify_range(idx_t beg_index, idx_t end_index) const {
46 assert(beg_index <= end_index, "BitMap range error");
47 // Note that [0,0) and [size,size) are both valid ranges.
48 if (end_index != _size) verify_index(end_index);
49 }
50 #endif // #ifdef ASSERT
51
52 void BitMap::resize(idx_t size_in_bits, bool in_resource_area) {
53 idx_t old_size_in_words = size_in_words();
54 bm_word_t* old_map = map();
55
56 _size = size_in_bits;
57 idx_t new_size_in_words = size_in_words();
58 if (in_resource_area) {
59 _map = NEW_RESOURCE_ARRAY(bm_word_t, new_size_in_words);
60 Copy::disjoint_words((HeapWord*)old_map, (HeapWord*) _map,
61 MIN2(old_size_in_words, new_size_in_words));
62 } else {
63 _map = ArrayAllocator<bm_word_t, mtInternal>::reallocate(old_map, old_size_in_words, new_size_in_words);
64 }
65
66 if (new_size_in_words > old_size_in_words) {
67 clear_range_of_words(old_size_in_words, new_size_in_words);
68 }
69 }
70
71 void BitMap::pretouch() {
72 os::pretouch_memory((char*)word_addr(0), (char*)word_addr(size()));
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 = res;
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::at_put(idx_t offset, bool value) {
180 if (value) {
181 set_bit(offset);
182 } else {
183 clear_bit(offset);
184 }
185 }
186
187 // Return true to indicate that this thread changed
188 // the bit, false to indicate that someone else did.
189 // In either case, the requested bit is in the
190 // requested state some time during the period that
191 // this thread is executing this call. More importantly,
192 // if no other thread is executing an action to
193 // change the requested bit to a state other than
194 // the one that this thread is trying to set it to,
195 // then the the bit is in the expected state
196 // at exit from this method. However, rather than
197 // make such a strong assertion here, based on
198 // assuming such constrained use (which though true
199 // today, could change in the future to service some
200 // funky parallel algorithm), we encourage callers
201 // to do such verification, as and when appropriate.
202 bool BitMap::par_at_put(idx_t bit, bool value) {
203 return value ? par_set_bit(bit) : par_clear_bit(bit);
204 }
205
206 void BitMap::at_put_grow(idx_t offset, bool value) {
207 if (offset >= size()) {
208 resize(2 * MAX2(size(), offset));
209 }
210 at_put(offset, value);
211 }
212
213 void BitMap::at_put_range(idx_t start_offset, idx_t end_offset, bool value) {
214 if (value) {
215 set_range(start_offset, end_offset);
216 } else {
217 clear_range(start_offset, end_offset);
218 }
219 }
220
221 void BitMap::par_at_put_range(idx_t beg, idx_t end, bool value) {
222 verify_range(beg, end);
223
224 idx_t beg_full_word = word_index_round_up(beg);
225 idx_t end_full_word = word_index(end);
226
227 if (beg_full_word < end_full_word) {
228 // The range includes at least one full word.
229 par_put_range_within_word(beg, bit_index(beg_full_word), value);
230 if (value) {
231 set_range_of_words(beg_full_word, end_full_word);
232 } else {
233 clear_range_of_words(beg_full_word, end_full_word);
234 }
235 par_put_range_within_word(bit_index(end_full_word), end, value);
236 } else {
237 // The range spans at most 2 partial words.
238 idx_t boundary = MIN2(bit_index(beg_full_word), end);
239 par_put_range_within_word(beg, boundary, value);
240 par_put_range_within_word(boundary, end, value);
241 }
242
243 }
244
245 void BitMap::at_put_large_range(idx_t beg, idx_t end, bool value) {
246 if (value) {
247 set_large_range(beg, end);
248 } else {
249 clear_large_range(beg, end);
250 }
251 }
252
253 void BitMap::par_at_put_large_range(idx_t beg, idx_t end, bool value) {
254 verify_range(beg, end);
255
256 idx_t beg_full_word = word_index_round_up(beg);
257 idx_t end_full_word = word_index(end);
258
259 assert(end_full_word - beg_full_word >= 32,
260 "the range must include at least 32 bytes");
261
262 // The range includes at least one full word.
263 par_put_range_within_word(beg, bit_index(beg_full_word), value);
264 if (value) {
265 set_large_range_of_words(beg_full_word, end_full_word);
266 } else {
267 clear_large_range_of_words(beg_full_word, end_full_word);
268 }
269 par_put_range_within_word(bit_index(end_full_word), end, value);
270 }
271
272 bool BitMap::contains(const BitMap other) const {
273 assert(size() == other.size(), "must have same size");
274 bm_word_t* dest_map = map();
275 bm_word_t* other_map = other.map();
276 idx_t size = size_in_words();
277 for (idx_t index = 0; index < size_in_words(); index++) {
278 bm_word_t word_union = dest_map[index] | other_map[index];
279 // If this has more bits set than dest_map[index], then other is not a
280 // subset.
281 if (word_union != dest_map[index]) return false;
282 }
283 return true;
284 }
285
286 bool BitMap::intersects(const BitMap other) const {
287 assert(size() == other.size(), "must have same size");
288 bm_word_t* dest_map = map();
289 bm_word_t* other_map = other.map();
290 idx_t size = size_in_words();
291 for (idx_t index = 0; index < size_in_words(); index++) {
292 if ((dest_map[index] & other_map[index]) != 0) return true;
293 }
294 // Otherwise, no intersection.
295 return false;
296 }
297
298 void BitMap::set_union(BitMap other) {
299 assert(size() == other.size(), "must have same size");
300 bm_word_t* dest_map = map();
301 bm_word_t* other_map = other.map();
302 idx_t size = size_in_words();
303 for (idx_t index = 0; index < size_in_words(); index++) {
304 dest_map[index] = dest_map[index] | other_map[index];
305 }
306 }
307
308
309 void BitMap::set_difference(BitMap other) {
310 assert(size() == other.size(), "must have same size");
311 bm_word_t* dest_map = map();
312 bm_word_t* other_map = other.map();
313 idx_t size = size_in_words();
314 for (idx_t index = 0; index < size_in_words(); index++) {
315 dest_map[index] = dest_map[index] & ~(other_map[index]);
316 }
317 }
318
319
320 void BitMap::set_intersection(BitMap other) {
321 assert(size() == other.size(), "must have same size");
322 bm_word_t* dest_map = map();
323 bm_word_t* other_map = other.map();
324 idx_t size = size_in_words();
325 for (idx_t index = 0; index < size; index++) {
326 dest_map[index] = dest_map[index] & other_map[index];
327 }
328 }
329
330
331 void BitMap::set_intersection_at_offset(BitMap other, idx_t offset) {
332 assert(other.size() >= offset, "offset not in range");
333 assert(other.size() - offset >= size(), "other not large enough");
334 // XXX Ideally, we would remove this restriction.
335 guarantee((offset % (sizeof(bm_word_t) * BitsPerByte)) == 0,
336 "Only handle aligned cases so far.");
337 bm_word_t* dest_map = map();
338 bm_word_t* other_map = other.map();
339 idx_t offset_word_ind = word_index(offset);
340 idx_t size = size_in_words();
341 for (idx_t index = 0; index < size; index++) {
342 dest_map[index] = dest_map[index] & other_map[offset_word_ind + index];
343 }
344 }
345
346 bool BitMap::set_union_with_result(BitMap other) {
347 assert(size() == other.size(), "must have same size");
348 bool changed = false;
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; index++) {
353 idx_t temp = dest_map[index] | other_map[index];
354 changed = changed || (temp != dest_map[index]);
355 dest_map[index] = temp;
356 }
357 return changed;
358 }
359
360
361 bool BitMap::set_difference_with_result(BitMap other) {
362 assert(size() == other.size(), "must have same size");
363 bool changed = false;
364 bm_word_t* dest_map = map();
365 bm_word_t* other_map = other.map();
366 idx_t size = size_in_words();
367 for (idx_t index = 0; index < size; index++) {
368 bm_word_t temp = dest_map[index] & ~(other_map[index]);
369 changed = changed || (temp != dest_map[index]);
370 dest_map[index] = temp;
371 }
372 return changed;
373 }
374
375
376 bool BitMap::set_intersection_with_result(BitMap other) {
377 assert(size() == other.size(), "must have same size");
378 bool changed = false;
379 bm_word_t* dest_map = map();
380 bm_word_t* other_map = other.map();
381 idx_t size = size_in_words();
382 for (idx_t index = 0; index < size; index++) {
383 bm_word_t orig = dest_map[index];
384 bm_word_t temp = orig & other_map[index];
385 changed = changed || (temp != orig);
386 dest_map[index] = temp;
387 }
388 return changed;
389 }
390
391
392 void BitMap::set_from(BitMap other) {
393 assert(size() == other.size(), "must have same size");
394 bm_word_t* dest_map = map();
395 bm_word_t* other_map = other.map();
396 idx_t size = size_in_words();
397 for (idx_t index = 0; index < size; index++) {
398 dest_map[index] = other_map[index];
399 }
400 }
401
402
403 bool BitMap::is_same(BitMap other) {
404 assert(size() == other.size(), "must have same size");
405 bm_word_t* dest_map = map();
406 bm_word_t* other_map = other.map();
407 idx_t size = size_in_words();
408 for (idx_t index = 0; index < size; index++) {
409 if (dest_map[index] != other_map[index]) return false;
410 }
411 return true;
412 }
413
414 bool BitMap::is_full() const {
415 bm_word_t* word = map();
416 idx_t rest = size();
417 for (; rest >= (idx_t) BitsPerWord; rest -= BitsPerWord) {
418 if (*word != ~(bm_word_t)0) return false;
419 word++;
420 }
421 return rest == 0 || (*word | ~right_n_bits((int)rest)) == ~(bm_word_t)0;
422 }
423
424
425 bool BitMap::is_empty() const {
426 bm_word_t* word = map();
427 idx_t rest = size();
428 for (; rest >= (idx_t) BitsPerWord; rest -= BitsPerWord) {
429 if (*word != 0) return false;
430 word++;
431 }
432 return rest == 0 || (*word & right_n_bits((int)rest)) == 0;
433 }
434
435 void BitMap::clear_large() {
436 clear_large_range_of_words(0, size_in_words());
437 }
438
439 // Note that if the closure itself modifies the bitmap
440 // then modifications in and to the left of the _bit_ being
441 // currently sampled will not be seen. Note also that the
442 // interval [leftOffset, rightOffset) is right open.
443 bool BitMap::iterate(BitMapClosure* blk, idx_t leftOffset, idx_t rightOffset) {
444 verify_range(leftOffset, rightOffset);
445
446 idx_t startIndex = word_index(leftOffset);
447 idx_t endIndex = MIN2(word_index(rightOffset) + 1, size_in_words());
448 for (idx_t index = startIndex, offset = leftOffset;
449 offset < rightOffset && index < endIndex;
450 offset = (++index) << LogBitsPerWord) {
451 idx_t rest = map(index) >> (offset & (BitsPerWord - 1));
452 for (; offset < rightOffset && rest != 0; offset++) {
453 if (rest & 1) {
454 if (!blk->do_bit(offset)) return false;
455 // resample at each closure application
456 // (see, for instance, CMS bug 4525989)
457 rest = map(index) >> (offset & (BitsPerWord -1));
458 }
459 rest = rest >> 1;
460 }
461 }
462 return true;
463 }
464
465 BitMap::idx_t* BitMap::_pop_count_table = NULL;
466
467 void BitMap::init_pop_count_table() {
468 if (_pop_count_table == NULL) {
469 BitMap::idx_t *table = NEW_C_HEAP_ARRAY(idx_t, 256, mtInternal);
470 for (uint i = 0; i < 256; i++) {
471 table[i] = num_set_bits(i);
472 }
473
474 intptr_t res = Atomic::cmpxchg_ptr((intptr_t) table,
475 (intptr_t*) &_pop_count_table,
476 (intptr_t) NULL_WORD);
477 if (res != NULL_WORD) {
478 guarantee( _pop_count_table == (void*) res, "invariant" );
479 FREE_C_HEAP_ARRAY(idx_t, table);
480 }
481 }
482 }
483
484 BitMap::idx_t BitMap::num_set_bits(bm_word_t w) {
485 idx_t bits = 0;
486
487 while (w != 0) {
488 while ((w & 1) == 0) {
489 w >>= 1;
490 }
491 bits++;
492 w >>= 1;
493 }
494 return bits;
495 }
496
497 BitMap::idx_t BitMap::num_set_bits_from_table(unsigned char c) {
498 assert(_pop_count_table != NULL, "precondition");
499 return _pop_count_table[c];
500 }
501
502 BitMap::idx_t BitMap::count_one_bits() const {
503 init_pop_count_table(); // If necessary.
504 idx_t sum = 0;
505 typedef unsigned char uchar;
506 for (idx_t i = 0; i < size_in_words(); i++) {
507 bm_word_t w = map()[i];
508 for (size_t j = 0; j < sizeof(bm_word_t); j++) {
509 sum += num_set_bits_from_table(uchar(w & 255));
510 w >>= 8;
511 }
512 }
513 return sum;
514 }
515
516 void BitMap::print_on_error(outputStream* st, const char* prefix) const {
517 st->print_cr("%s[" PTR_FORMAT ", " PTR_FORMAT ")",
518 prefix, p2i(map()), p2i((char*)map() + (size() >> LogBitsPerByte)));
519 }
520
521 #ifndef PRODUCT
522
523 void BitMap::print_on(outputStream* st) const {
524 tty->print("Bitmap(" SIZE_FORMAT "):", size());
525 for (idx_t index = 0; index < size(); index++) {
526 tty->print("%c", at(index) ? '1' : '0');
527 }
528 tty->cr();
529 }
530
531 class TestBitMap : public AllStatic {
532 const static BitMap::idx_t BITMAP_SIZE = 1024;
533 static void fillBitMap(BitMap& map) {
534 map.set_bit(1);
535 map.set_bit(3);
536 map.set_bit(17);
537 map.set_bit(512);
538 }
539
540 static void testResize(bool in_resource_area) {
541 {
542 BitMap map(0, in_resource_area);
543 map.resize(BITMAP_SIZE, in_resource_area);
544 fillBitMap(map);
545
546 BitMap map2(BITMAP_SIZE, in_resource_area);
547 fillBitMap(map2);
548 assert(map.is_same(map2), "could be");
549 }
550
551 {
552 BitMap map(128, in_resource_area);
553 map.resize(BITMAP_SIZE, in_resource_area);
554 fillBitMap(map);
555
556 BitMap map2(BITMAP_SIZE, in_resource_area);
557 fillBitMap(map2);
558 assert(map.is_same(map2), "could be");
559 }
560
561 {
562 BitMap map(BITMAP_SIZE, in_resource_area);
563 map.resize(BITMAP_SIZE, in_resource_area);
564 fillBitMap(map);
565
566 BitMap map2(BITMAP_SIZE, in_resource_area);
567 fillBitMap(map2);
568 assert(map.is_same(map2), "could be");
569 }
570 }
571
572 static void testResizeResource() {
573 ResourceMark rm;
574 testResize(true);
575 }
576
577 static void testResizeNonResource() {
578 const size_t bitmap_bytes = BITMAP_SIZE / BitsPerByte;
579
580 // Test the default behavior
581 testResize(false);
582
583 {
584 // Make sure that AllocatorMallocLimit is larger than our allocation request
585 // forcing it to call standard malloc()
586 SizeTFlagSetting fs(ArrayAllocatorMallocLimit, bitmap_bytes * 4);
587 testResize(false);
588 }
589 {
590 // Make sure that AllocatorMallocLimit is smaller than our allocation request
591 // forcing it to call mmap() (or equivalent)
592 SizeTFlagSetting fs(ArrayAllocatorMallocLimit, bitmap_bytes / 4);
593 testResize(false);
594 }
595 }
596
597 public:
598 static void test() {
599 testResizeResource();
600 testResizeNonResource();
601 }
602
603 };
604
605 void TestBitMap_test() {
606 TestBitMap::test();
607 }
608 #endif
609
610
611 BitMap2D::BitMap2D(bm_word_t* map, idx_t size_in_slots, idx_t bits_per_slot)
612 : _bits_per_slot(bits_per_slot)
613 , _map(map, size_in_slots * bits_per_slot)
614 {
615 }
616
617
618 BitMap2D::BitMap2D(idx_t size_in_slots, idx_t bits_per_slot)
619 : _bits_per_slot(bits_per_slot)
620 , _map(size_in_slots * bits_per_slot)
621 {
622 }