comparison src/share/vm/utilities/bitMap.cpp @ 0:a61af66fc99e jdk7-b24

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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1 /*
2 * Copyright 1997-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 # include "incls/_precompiled.incl"
26 # include "incls/_bitMap.cpp.incl"
27
28
29 BitMap::BitMap(idx_t* map, idx_t size_in_bits) {
30 assert(size_in_bits >= 0, "just checking");
31 _map = map;
32 _size = size_in_bits;
33 }
34
35
36 BitMap::BitMap(idx_t size_in_bits) {
37 assert(size_in_bits >= 0, "just checking");
38 _size = size_in_bits;
39 _map = NEW_RESOURCE_ARRAY(idx_t, size_in_words());
40 }
41
42
43 void BitMap::resize(idx_t size_in_bits) {
44 assert(size_in_bits >= 0, "just checking");
45 size_t old_size_in_words = size_in_words();
46 uintptr_t* old_map = map();
47 _size = size_in_bits;
48 size_t new_size_in_words = size_in_words();
49 _map = NEW_RESOURCE_ARRAY(idx_t, new_size_in_words);
50 Copy::disjoint_words((HeapWord*) old_map, (HeapWord*) _map, MIN2(old_size_in_words, new_size_in_words));
51 if (new_size_in_words > old_size_in_words) {
52 clear_range_of_words(old_size_in_words, size_in_words());
53 }
54 }
55
56 // Returns a bit mask for a range of bits [beg, end) within a single word. Each
57 // bit in the mask is 0 if the bit is in the range, 1 if not in the range. The
58 // returned mask can be used directly to clear the range, or inverted to set the
59 // range. Note: end must not be 0.
60 inline BitMap::idx_t
61 BitMap::inverted_bit_mask_for_range(idx_t beg, idx_t end) const {
62 assert(end != 0, "does not work when end == 0");
63 assert(beg == end || word_index(beg) == word_index(end - 1),
64 "must be a single-word range");
65 idx_t mask = bit_mask(beg) - 1; // low (right) bits
66 if (bit_in_word(end) != 0) {
67 mask |= ~(bit_mask(end) - 1); // high (left) bits
68 }
69 return mask;
70 }
71
72 void BitMap::set_range_within_word(idx_t beg, idx_t end) {
73 // With a valid range (beg <= end), this test ensures that end != 0, as
74 // required by inverted_bit_mask_for_range. Also avoids an unnecessary write.
75 if (beg != end) {
76 idx_t mask = inverted_bit_mask_for_range(beg, end);
77 *word_addr(beg) |= ~mask;
78 }
79 }
80
81 void BitMap::clear_range_within_word(idx_t beg, idx_t end) {
82 // With a valid range (beg <= end), this test ensures that end != 0, as
83 // required by inverted_bit_mask_for_range. Also avoids an unnecessary write.
84 if (beg != end) {
85 idx_t mask = inverted_bit_mask_for_range(beg, end);
86 *word_addr(beg) &= mask;
87 }
88 }
89
90 void BitMap::par_put_range_within_word(idx_t beg, idx_t end, bool value) {
91 assert(value == 0 || value == 1, "0 for clear, 1 for set");
92 // With a valid range (beg <= end), this test ensures that end != 0, as
93 // required by inverted_bit_mask_for_range. Also avoids an unnecessary write.
94 if (beg != end) {
95 intptr_t* pw = (intptr_t*)word_addr(beg);
96 intptr_t w = *pw;
97 intptr_t mr = (intptr_t)inverted_bit_mask_for_range(beg, end);
98 intptr_t nw = value ? (w | ~mr) : (w & mr);
99 while (true) {
100 intptr_t res = Atomic::cmpxchg_ptr(nw, pw, w);
101 if (res == w) break;
102 w = *pw;
103 nw = value ? (w | ~mr) : (w & mr);
104 }
105 }
106 }
107
108 inline void BitMap::set_large_range_of_words(idx_t beg, idx_t end) {
109 memset(_map + beg, ~(unsigned char)0, (end - beg) * sizeof(uintptr_t));
110 }
111
112 inline void BitMap::clear_large_range_of_words(idx_t beg, idx_t end) {
113 memset(_map + beg, 0, (end - beg) * sizeof(uintptr_t));
114 }
115
116 inline BitMap::idx_t BitMap::word_index_round_up(idx_t bit) const {
117 idx_t bit_rounded_up = bit + (BitsPerWord - 1);
118 // Check for integer arithmetic overflow.
119 return bit_rounded_up > bit ? word_index(bit_rounded_up) : size_in_words();
120 }
121
122 void BitMap::set_range(idx_t beg, idx_t end) {
123 verify_range(beg, end);
124
125 idx_t beg_full_word = word_index_round_up(beg);
126 idx_t end_full_word = word_index(end);
127
128 if (beg_full_word < end_full_word) {
129 // The range includes at least one full word.
130 set_range_within_word(beg, bit_index(beg_full_word));
131 set_range_of_words(beg_full_word, end_full_word);
132 set_range_within_word(bit_index(end_full_word), end);
133 } else {
134 // The range spans at most 2 partial words.
135 idx_t boundary = MIN2(bit_index(beg_full_word), end);
136 set_range_within_word(beg, boundary);
137 set_range_within_word(boundary, end);
138 }
139 }
140
141 void BitMap::clear_range(idx_t beg, idx_t end) {
142 verify_range(beg, end);
143
144 idx_t beg_full_word = word_index_round_up(beg);
145 idx_t end_full_word = word_index(end);
146
147 if (beg_full_word < end_full_word) {
148 // The range includes at least one full word.
149 clear_range_within_word(beg, bit_index(beg_full_word));
150 clear_range_of_words(beg_full_word, end_full_word);
151 clear_range_within_word(bit_index(end_full_word), end);
152 } else {
153 // The range spans at most 2 partial words.
154 idx_t boundary = MIN2(bit_index(beg_full_word), end);
155 clear_range_within_word(beg, boundary);
156 clear_range_within_word(boundary, end);
157 }
158 }
159
160 void BitMap::set_large_range(idx_t beg, idx_t end) {
161 verify_range(beg, end);
162
163 idx_t beg_full_word = word_index_round_up(beg);
164 idx_t end_full_word = word_index(end);
165
166 assert(end_full_word - beg_full_word >= 32,
167 "the range must include at least 32 bytes");
168
169 // The range includes at least one full word.
170 set_range_within_word(beg, bit_index(beg_full_word));
171 set_large_range_of_words(beg_full_word, end_full_word);
172 set_range_within_word(bit_index(end_full_word), end);
173 }
174
175 void BitMap::clear_large_range(idx_t beg, idx_t end) {
176 verify_range(beg, end);
177
178 idx_t beg_full_word = word_index_round_up(beg);
179 idx_t end_full_word = word_index(end);
180
181 assert(end_full_word - beg_full_word >= 32,
182 "the range must include at least 32 bytes");
183
184 // The range includes at least one full word.
185 clear_range_within_word(beg, bit_index(beg_full_word));
186 clear_large_range_of_words(beg_full_word, end_full_word);
187 clear_range_within_word(bit_index(end_full_word), end);
188 }
189
190 void BitMap::at_put(idx_t offset, bool value) {
191 if (value) {
192 set_bit(offset);
193 } else {
194 clear_bit(offset);
195 }
196 }
197
198 // Return true to indicate that this thread changed
199 // the bit, false to indicate that someone else did.
200 // In either case, the requested bit is in the
201 // requested state some time during the period that
202 // this thread is executing this call. More importantly,
203 // if no other thread is executing an action to
204 // change the requested bit to a state other than
205 // the one that this thread is trying to set it to,
206 // then the the bit is in the expected state
207 // at exit from this method. However, rather than
208 // make such a strong assertion here, based on
209 // assuming such constrained use (which though true
210 // today, could change in the future to service some
211 // funky parallel algorithm), we encourage callers
212 // to do such verification, as and when appropriate.
213 bool BitMap::par_at_put(idx_t bit, bool value) {
214 return value ? par_set_bit(bit) : par_clear_bit(bit);
215 }
216
217 void BitMap::at_put_grow(idx_t offset, bool value) {
218 if (offset >= size()) {
219 resize(2 * MAX2(size(), offset));
220 }
221 at_put(offset, value);
222 }
223
224 void BitMap::at_put_range(idx_t start_offset, idx_t end_offset, bool value) {
225 if (value) {
226 set_range(start_offset, end_offset);
227 } else {
228 clear_range(start_offset, end_offset);
229 }
230 }
231
232 void BitMap::par_at_put_range(idx_t beg, idx_t end, bool value) {
233 verify_range(beg, end);
234
235 idx_t beg_full_word = word_index_round_up(beg);
236 idx_t end_full_word = word_index(end);
237
238 if (beg_full_word < end_full_word) {
239 // The range includes at least one full word.
240 par_put_range_within_word(beg, bit_index(beg_full_word), value);
241 if (value) {
242 set_range_of_words(beg_full_word, end_full_word);
243 } else {
244 clear_range_of_words(beg_full_word, end_full_word);
245 }
246 par_put_range_within_word(bit_index(end_full_word), end, value);
247 } else {
248 // The range spans at most 2 partial words.
249 idx_t boundary = MIN2(bit_index(beg_full_word), end);
250 par_put_range_within_word(beg, boundary, value);
251 par_put_range_within_word(boundary, end, value);
252 }
253
254 }
255
256 void BitMap::at_put_large_range(idx_t beg, idx_t end, bool value) {
257 if (value) {
258 set_large_range(beg, end);
259 } else {
260 clear_large_range(beg, end);
261 }
262 }
263
264 void BitMap::par_at_put_large_range(idx_t beg, idx_t end, bool value) {
265 verify_range(beg, end);
266
267 idx_t beg_full_word = word_index_round_up(beg);
268 idx_t end_full_word = word_index(end);
269
270 assert(end_full_word - beg_full_word >= 32,
271 "the range must include at least 32 bytes");
272
273 // The range includes at least one full word.
274 par_put_range_within_word(beg, bit_index(beg_full_word), value);
275 if (value) {
276 set_large_range_of_words(beg_full_word, end_full_word);
277 } else {
278 clear_large_range_of_words(beg_full_word, end_full_word);
279 }
280 par_put_range_within_word(bit_index(end_full_word), end, value);
281 }
282
283 bool BitMap::contains(const BitMap other) const {
284 assert(size() == other.size(), "must have same size");
285 uintptr_t* dest_map = map();
286 uintptr_t* other_map = other.map();
287 idx_t size = size_in_words();
288 for (idx_t index = 0; index < size_in_words(); index++) {
289 uintptr_t word_union = dest_map[index] | other_map[index];
290 // If this has more bits set than dest_map[index], then other is not a
291 // subset.
292 if (word_union != dest_map[index]) return false;
293 }
294 return true;
295 }
296
297 bool BitMap::intersects(const BitMap other) const {
298 assert(size() == other.size(), "must have same size");
299 uintptr_t* dest_map = map();
300 uintptr_t* other_map = other.map();
301 idx_t size = size_in_words();
302 for (idx_t index = 0; index < size_in_words(); index++) {
303 if ((dest_map[index] & other_map[index]) != 0) return true;
304 }
305 // Otherwise, no intersection.
306 return false;
307 }
308
309 void BitMap::set_union(BitMap other) {
310 assert(size() == other.size(), "must have same size");
311 idx_t* dest_map = map();
312 idx_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_difference(BitMap other) {
321 assert(size() == other.size(), "must have same size");
322 idx_t* dest_map = map();
323 idx_t* other_map = other.map();
324 idx_t size = size_in_words();
325 for (idx_t index = 0; index < size_in_words(); index++) {
326 dest_map[index] = dest_map[index] & ~(other_map[index]);
327 }
328 }
329
330
331 void BitMap::set_intersection(BitMap other) {
332 assert(size() == other.size(), "must have same size");
333 idx_t* dest_map = map();
334 idx_t* other_map = other.map();
335 idx_t size = size_in_words();
336 for (idx_t index = 0; index < size; index++) {
337 dest_map[index] = dest_map[index] & other_map[index];
338 }
339 }
340
341
342 bool BitMap::set_union_with_result(BitMap other) {
343 assert(size() == other.size(), "must have same size");
344 bool changed = false;
345 idx_t* dest_map = map();
346 idx_t* other_map = other.map();
347 idx_t size = size_in_words();
348 for (idx_t index = 0; index < size; index++) {
349 idx_t temp = map(index) | other_map[index];
350 changed = changed || (temp != map(index));
351 map()[index] = temp;
352 }
353 return changed;
354 }
355
356
357 bool BitMap::set_difference_with_result(BitMap other) {
358 assert(size() == other.size(), "must have same size");
359 bool changed = false;
360 idx_t* dest_map = map();
361 idx_t* other_map = other.map();
362 idx_t size = size_in_words();
363 for (idx_t index = 0; index < size; index++) {
364 idx_t temp = dest_map[index] & ~(other_map[index]);
365 changed = changed || (temp != dest_map[index]);
366 dest_map[index] = temp;
367 }
368 return changed;
369 }
370
371
372 bool BitMap::set_intersection_with_result(BitMap other) {
373 assert(size() == other.size(), "must have same size");
374 bool changed = false;
375 idx_t* dest_map = map();
376 idx_t* other_map = other.map();
377 idx_t size = size_in_words();
378 for (idx_t index = 0; index < size; index++) {
379 idx_t orig = dest_map[index];
380 idx_t temp = orig & other_map[index];
381 changed = changed || (temp != orig);
382 dest_map[index] = temp;
383 }
384 return changed;
385 }
386
387
388 void BitMap::set_from(BitMap other) {
389 assert(size() == other.size(), "must have same size");
390 idx_t* dest_map = map();
391 idx_t* other_map = other.map();
392 idx_t size = size_in_words();
393 for (idx_t index = 0; index < size; index++) {
394 dest_map[index] = other_map[index];
395 }
396 }
397
398
399 bool BitMap::is_same(BitMap other) {
400 assert(size() == other.size(), "must have same size");
401 idx_t* dest_map = map();
402 idx_t* other_map = other.map();
403 idx_t size = size_in_words();
404 for (idx_t index = 0; index < size; index++) {
405 if (dest_map[index] != other_map[index]) return false;
406 }
407 return true;
408 }
409
410 bool BitMap::is_full() const {
411 uintptr_t* word = map();
412 idx_t rest = size();
413 for (; rest >= (idx_t) BitsPerWord; rest -= BitsPerWord) {
414 if (*word != (uintptr_t) AllBits) return false;
415 word++;
416 }
417 return rest == 0 || (*word | ~right_n_bits((int)rest)) == (uintptr_t) AllBits;
418 }
419
420
421 bool BitMap::is_empty() const {
422 uintptr_t* word = map();
423 idx_t rest = size();
424 for (; rest >= (idx_t) BitsPerWord; rest -= BitsPerWord) {
425 if (*word != (uintptr_t) NoBits) return false;
426 word++;
427 }
428 return rest == 0 || (*word & right_n_bits((int)rest)) == (uintptr_t) NoBits;
429 }
430
431 void BitMap::clear_large() {
432 clear_large_range_of_words(0, size_in_words());
433 }
434
435 // Note that if the closure itself modifies the bitmap
436 // then modifications in and to the left of the _bit_ being
437 // currently sampled will not be seen. Note also that the
438 // interval [leftOffset, rightOffset) is right open.
439 void BitMap::iterate(BitMapClosure* blk, idx_t leftOffset, idx_t rightOffset) {
440 verify_range(leftOffset, rightOffset);
441
442 idx_t startIndex = word_index(leftOffset);
443 idx_t endIndex = MIN2(word_index(rightOffset) + 1, size_in_words());
444 for (idx_t index = startIndex, offset = leftOffset;
445 offset < rightOffset && index < endIndex;
446 offset = (++index) << LogBitsPerWord) {
447 idx_t rest = map(index) >> (offset & (BitsPerWord - 1));
448 for (; offset < rightOffset && rest != (uintptr_t)NoBits; offset++) {
449 if (rest & 1) {
450 blk->do_bit(offset);
451 // resample at each closure application
452 // (see, for instance, CMS bug 4525989)
453 rest = map(index) >> (offset & (BitsPerWord -1));
454 // XXX debugging: remove
455 // The following assertion assumes that closure application
456 // doesn't clear bits (may not be true in general, e.g. G1).
457 assert(rest & 1,
458 "incorrect shift or closure application can clear bits?");
459 }
460 rest = rest >> 1;
461 }
462 }
463 }
464
465 BitMap::idx_t BitMap::get_next_one_offset(idx_t l_offset,
466 idx_t r_offset) const {
467 assert(l_offset <= size(), "BitMap index out of bounds");
468 assert(r_offset <= size(), "BitMap index out of bounds");
469 assert(l_offset <= r_offset, "l_offset > r_offset ?");
470
471 if (l_offset == r_offset) {
472 return l_offset;
473 }
474 idx_t index = word_index(l_offset);
475 idx_t r_index = word_index(r_offset-1) + 1;
476 idx_t res_offset = l_offset;
477
478 // check bits including and to the _left_ of offset's position
479 idx_t pos = bit_in_word(res_offset);
480 idx_t res = map(index) >> pos;
481 if (res != (uintptr_t)NoBits) {
482 // find the position of the 1-bit
483 for (; !(res & 1); res_offset++) {
484 res = res >> 1;
485 }
486 assert(res_offset >= l_offset, "just checking");
487 return MIN2(res_offset, r_offset);
488 }
489 // skip over all word length 0-bit runs
490 for (index++; index < r_index; index++) {
491 res = map(index);
492 if (res != (uintptr_t)NoBits) {
493 // found a 1, return the offset
494 for (res_offset = index << LogBitsPerWord; !(res & 1);
495 res_offset++) {
496 res = res >> 1;
497 }
498 assert(res & 1, "tautology; see loop condition");
499 assert(res_offset >= l_offset, "just checking");
500 return MIN2(res_offset, r_offset);
501 }
502 }
503 return r_offset;
504 }
505
506 BitMap::idx_t BitMap::get_next_zero_offset(idx_t l_offset,
507 idx_t r_offset) const {
508 assert(l_offset <= size(), "BitMap index out of bounds");
509 assert(r_offset <= size(), "BitMap index out of bounds");
510 assert(l_offset <= r_offset, "l_offset > r_offset ?");
511
512 if (l_offset == r_offset) {
513 return l_offset;
514 }
515 idx_t index = word_index(l_offset);
516 idx_t r_index = word_index(r_offset-1) + 1;
517 idx_t res_offset = l_offset;
518
519 // check bits including and to the _left_ of offset's position
520 idx_t pos = res_offset & (BitsPerWord - 1);
521 idx_t res = (map(index) >> pos) | left_n_bits((int)pos);
522
523 if (res != (uintptr_t)AllBits) {
524 // find the position of the 0-bit
525 for (; res & 1; res_offset++) {
526 res = res >> 1;
527 }
528 assert(res_offset >= l_offset, "just checking");
529 return MIN2(res_offset, r_offset);
530 }
531 // skip over all word length 1-bit runs
532 for (index++; index < r_index; index++) {
533 res = map(index);
534 if (res != (uintptr_t)AllBits) {
535 // found a 0, return the offset
536 for (res_offset = index << LogBitsPerWord; res & 1;
537 res_offset++) {
538 res = res >> 1;
539 }
540 assert(!(res & 1), "tautology; see loop condition");
541 assert(res_offset >= l_offset, "just checking");
542 return MIN2(res_offset, r_offset);
543 }
544 }
545 return r_offset;
546 }
547
548 #ifndef PRODUCT
549
550 void BitMap::print_on(outputStream* st) const {
551 tty->print("Bitmap(%d):", size());
552 for (idx_t index = 0; index < size(); index++) {
553 tty->print("%c", at(index) ? '1' : '0');
554 }
555 tty->cr();
556 }
557
558 #endif
559
560
561 BitMap2D::BitMap2D(uintptr_t* map, idx_t size_in_slots, idx_t bits_per_slot)
562 : _bits_per_slot(bits_per_slot)
563 , _map(map, size_in_slots * bits_per_slot)
564 {
565 }
566
567
568 BitMap2D::BitMap2D(idx_t size_in_slots, idx_t bits_per_slot)
569 : _bits_per_slot(bits_per_slot)
570 , _map(size_in_slots * bits_per_slot)
571 {
572 }