1 /*
2 * Copyright (c) 2005, 2013, 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 #ifndef SHARE_VM_UTILITIES_BITMAP_INLINE_HPP
26 #define SHARE_VM_UTILITIES_BITMAP_INLINE_HPP
27
28 #include "runtime/atomic.inline.hpp"
29 #include "utilities/bitMap.hpp"
30
31 #ifdef ASSERT
32 inline void BitMap::verify_index(idx_t index) const {
33 assert(index < _size, "BitMap index out of bounds");
34 }
35
36 inline void BitMap::verify_range(idx_t beg_index, idx_t end_index) const {
37 assert(beg_index <= end_index, "BitMap range error");
38 // Note that [0,0) and [size,size) are both valid ranges.
39 if (end_index != _size) verify_index(end_index);
40 }
41 #endif // #ifdef ASSERT
42
43 inline void BitMap::set_bit(idx_t bit) {
44 verify_index(bit);
45 *word_addr(bit) |= bit_mask(bit);
46 }
47
48 inline void BitMap::clear_bit(idx_t bit) {
49 verify_index(bit);
50 *word_addr(bit) &= ~bit_mask(bit);
51 }
52
53 inline bool BitMap::set_bit_with_result(idx_t bit) {
54 verify_index(bit);
55 bm_word_t old_val = *word_addr(bit);
56 bm_word_t new_val = old_val | bit_mask(bit);
57 *word_addr(bit) = new_val;
58 return (old_val != new_val);
59 }
60
61 inline bool BitMap::clear_bit_with_result(idx_t bit) {
62 verify_index(bit);
63 bm_word_t old_val = *word_addr(bit);
64 bm_word_t new_val = old_val & ~bit_mask(bit);
65 *word_addr(bit) = new_val;
66 return (old_val != new_val);
67 }
68
69 inline bool BitMap::par_set_bit(idx_t bit) {
70 verify_index(bit);
71 volatile bm_word_t* const addr = word_addr(bit);
72 const bm_word_t mask = bit_mask(bit);
73 bm_word_t old_val = *addr;
74
75 do {
76 const bm_word_t new_val = old_val | mask;
77 if (new_val == old_val) {
78 return false; // Someone else beat us to it.
79 }
80 const bm_word_t cur_val = (bm_word_t) Atomic::cmpxchg_ptr((void*) new_val,
81 (volatile void*) addr,
82 (void*) old_val);
83 if (cur_val == old_val) {
84 return true; // Success.
85 }
86 old_val = cur_val; // The value changed, try again.
87 } while (true);
88 }
89
90 inline bool BitMap::par_clear_bit(idx_t bit) {
91 verify_index(bit);
92 volatile bm_word_t* const addr = word_addr(bit);
93 const bm_word_t mask = ~bit_mask(bit);
94 bm_word_t old_val = *addr;
95
96 do {
97 const bm_word_t new_val = old_val & mask;
98 if (new_val == old_val) {
99 return false; // Someone else beat us to it.
100 }
101 const bm_word_t cur_val = (bm_word_t) Atomic::cmpxchg_ptr((void*) new_val,
102 (volatile void*) addr,
103 (void*) old_val);
104 if (cur_val == old_val) {
105 return true; // Success.
106 }
107 old_val = cur_val; // The value changed, try again.
108 } while (true);
109 }
110
111 inline void BitMap::set_range(idx_t beg, idx_t end, RangeSizeHint hint) {
112 if (hint == small_range && end - beg == 1) {
113 set_bit(beg);
114 } else {
115 if (hint == large_range) {
116 set_large_range(beg, end);
117 } else {
118 set_range(beg, end);
119 }
120 }
121 }
122
123 inline void BitMap::clear_range(idx_t beg, idx_t end, RangeSizeHint hint) {
124 if (hint == small_range && end - beg == 1) {
125 clear_bit(beg);
126 } else {
127 if (hint == large_range) {
128 clear_large_range(beg, end);
129 } else {
130 clear_range(beg, end);
131 }
132 }
133 }
134
135 inline void BitMap::par_set_range(idx_t beg, idx_t end, RangeSizeHint hint) {
136 if (hint == small_range && end - beg == 1) {
137 par_at_put(beg, true);
138 } else {
139 if (hint == large_range) {
140 par_at_put_large_range(beg, end, true);
141 } else {
142 par_at_put_range(beg, end, true);
143 }
144 }
145 }
146
147 inline void BitMap::set_range_of_words(idx_t beg, idx_t end) {
148 bm_word_t* map = _map;
149 for (idx_t i = beg; i < end; ++i) map[i] = ~(bm_word_t)0;
150 }
151
152
153 inline void BitMap::clear_range_of_words(idx_t beg, idx_t end) {
154 bm_word_t* map = _map;
155 for (idx_t i = beg; i < end; ++i) map[i] = 0;
156 }
157
158
159 inline void BitMap::clear() {
160 clear_range_of_words(0, size_in_words());
161 }
162
163
164 inline void BitMap::par_clear_range(idx_t beg, idx_t end, RangeSizeHint hint) {
165 if (hint == small_range && end - beg == 1) {
166 par_at_put(beg, false);
167 } else {
168 if (hint == large_range) {
169 par_at_put_large_range(beg, end, false);
170 } else {
171 par_at_put_range(beg, end, false);
172 }
173 }
174 }
175
176 inline BitMap::idx_t
177 BitMap::get_next_one_offset_inline(idx_t l_offset, idx_t r_offset) const {
178 assert(l_offset <= size(), "BitMap index out of bounds");
179 assert(r_offset <= size(), "BitMap index out of bounds");
180 assert(l_offset <= r_offset, "l_offset > r_offset ?");
181
182 if (l_offset == r_offset) {
183 return l_offset;
184 }
185 idx_t index = word_index(l_offset);
186 idx_t r_index = word_index(r_offset-1) + 1;
187 idx_t res_offset = l_offset;
188
189 // check bits including and to the _left_ of offset's position
190 idx_t pos = bit_in_word(res_offset);
191 bm_word_t res = map(index) >> pos;
192 if (res != 0) {
193 // find the position of the 1-bit
194 for (; !(res & 1); res_offset++) {
195 res = res >> 1;
196 }
197
198 #ifdef ASSERT
199 // In the following assert, if r_offset is not bitamp word aligned,
200 // checking that res_offset is strictly less than r_offset is too
201 // strong and will trip the assert.
202 //
203 // Consider the case where l_offset is bit 15 and r_offset is bit 17
204 // of the same map word, and where bits [15:16:17:18] == [00:00:00:01].
205 // All the bits in the range [l_offset:r_offset) are 0.
206 // The loop that calculates res_offset, above, would yield the offset
207 // of bit 18 because it's in the same map word as l_offset and there
208 // is a set bit in that map word above l_offset (i.e. res != NoBits).
209 //
210 // In this case, however, we can assert is that res_offset is strictly
211 // less than size() since we know that there is at least one set bit
212 // at an offset above, but in the same map word as, r_offset.
213 // Otherwise, if r_offset is word aligned then it will not be in the
214 // same map word as l_offset (unless it equals l_offset). So either
215 // there won't be a set bit between l_offset and the end of it's map
216 // word (i.e. res == NoBits), or res_offset will be less than r_offset.
217
218 idx_t limit = is_word_aligned(r_offset) ? r_offset : size();
219 assert(res_offset >= l_offset && res_offset < limit, "just checking");
220 #endif // ASSERT
221 return MIN2(res_offset, r_offset);
222 }
223 // skip over all word length 0-bit runs
224 for (index++; index < r_index; index++) {
225 res = map(index);
226 if (res != 0) {
227 // found a 1, return the offset
228 for (res_offset = bit_index(index); !(res & 1); res_offset++) {
229 res = res >> 1;
230 }
231 assert(res & 1, "tautology; see loop condition");
232 assert(res_offset >= l_offset, "just checking");
233 return MIN2(res_offset, r_offset);
234 }
235 }
236 return r_offset;
237 }
238
239 inline BitMap::idx_t
240 BitMap::get_next_zero_offset_inline(idx_t l_offset, idx_t r_offset) const {
241 assert(l_offset <= size(), "BitMap index out of bounds");
242 assert(r_offset <= size(), "BitMap index out of bounds");
243 assert(l_offset <= r_offset, "l_offset > r_offset ?");
244
245 if (l_offset == r_offset) {
246 return l_offset;
247 }
248 idx_t index = word_index(l_offset);
249 idx_t r_index = word_index(r_offset-1) + 1;
250 idx_t res_offset = l_offset;
251
252 // check bits including and to the _left_ of offset's position
253 idx_t pos = res_offset & (BitsPerWord - 1);
254 bm_word_t res = (map(index) >> pos) | left_n_bits((int)pos);
255
256 if (res != ~(bm_word_t)0) {
257 // find the position of the 0-bit
258 for (; res & 1; res_offset++) {
259 res = res >> 1;
260 }
261 assert(res_offset >= l_offset, "just checking");
262 return MIN2(res_offset, r_offset);
263 }
264 // skip over all word length 1-bit runs
265 for (index++; index < r_index; index++) {
266 res = map(index);
267 if (res != ~(bm_word_t)0) {
268 // found a 0, return the offset
269 for (res_offset = index << LogBitsPerWord; res & 1;
270 res_offset++) {
271 res = res >> 1;
272 }
273 assert(!(res & 1), "tautology; see loop condition");
274 assert(res_offset >= l_offset, "just checking");
275 return MIN2(res_offset, r_offset);
276 }
277 }
278 return r_offset;
279 }
280
281 inline BitMap::idx_t
282 BitMap::get_next_one_offset_inline_aligned_right(idx_t l_offset,
283 idx_t r_offset) const
284 {
285 verify_range(l_offset, r_offset);
286 assert(bit_in_word(r_offset) == 0, "r_offset not word-aligned");
287
288 if (l_offset == r_offset) {
289 return l_offset;
290 }
291 idx_t index = word_index(l_offset);
292 idx_t r_index = word_index(r_offset);
293 idx_t res_offset = l_offset;
294
295 // check bits including and to the _left_ of offset's position
296 bm_word_t res = map(index) >> bit_in_word(res_offset);
297 if (res != 0) {
298 // find the position of the 1-bit
299 for (; !(res & 1); res_offset++) {
300 res = res >> 1;
301 }
302 assert(res_offset >= l_offset &&
303 res_offset < r_offset, "just checking");
304 return res_offset;
305 }
306 // skip over all word length 0-bit runs
307 for (index++; index < r_index; index++) {
308 res = map(index);
309 if (res != 0) {
310 // found a 1, return the offset
311 for (res_offset = bit_index(index); !(res & 1); res_offset++) {
312 res = res >> 1;
313 }
314 assert(res & 1, "tautology; see loop condition");
315 assert(res_offset >= l_offset && res_offset < r_offset, "just checking");
316 return res_offset;
317 }
318 }
319 return r_offset;
320 }
321
322
323 // Returns a bit mask for a range of bits [beg, end) within a single word. Each
324 // bit in the mask is 0 if the bit is in the range, 1 if not in the range. The
325 // returned mask can be used directly to clear the range, or inverted to set the
326 // range. Note: end must not be 0.
327 inline BitMap::bm_word_t
328 BitMap::inverted_bit_mask_for_range(idx_t beg, idx_t end) const {
329 assert(end != 0, "does not work when end == 0");
330 assert(beg == end || word_index(beg) == word_index(end - 1),
331 "must be a single-word range");
332 bm_word_t mask = bit_mask(beg) - 1; // low (right) bits
333 if (bit_in_word(end) != 0) {
334 mask |= ~(bit_mask(end) - 1); // high (left) bits
335 }
336 return mask;
337 }
338
339 inline void BitMap::set_large_range_of_words(idx_t beg, idx_t end) {
340 memset(_map + beg, ~(unsigned char)0, (end - beg) * sizeof(bm_word_t));
341 }
342
343 inline void BitMap::clear_large_range_of_words(idx_t beg, idx_t end) {
344 memset(_map + beg, 0, (end - beg) * sizeof(bm_word_t));
345 }
346
347 inline BitMap::idx_t BitMap::word_index_round_up(idx_t bit) const {
348 idx_t bit_rounded_up = bit + (BitsPerWord - 1);
349 // Check for integer arithmetic overflow.
350 return bit_rounded_up > bit ? word_index(bit_rounded_up) : size_in_words();
351 }
352
353 inline BitMap::idx_t BitMap::get_next_one_offset(idx_t l_offset,
354 idx_t r_offset) const {
355 return get_next_one_offset_inline(l_offset, r_offset);
356 }
357
358 inline BitMap::idx_t BitMap::get_next_zero_offset(idx_t l_offset,
359 idx_t r_offset) const {
360 return get_next_zero_offset_inline(l_offset, r_offset);
361 }
362
363 inline void BitMap2D::clear() {
364 _map.clear();
365 }
366
367 #endif // SHARE_VM_UTILITIES_BITMAP_INLINE_HPP