1 /*
2 * Copyright (c) 2005, 2012, 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.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::par_set_bit(idx_t bit) {
54 verify_index(bit);
55 volatile idx_t* const addr = word_addr(bit);
56 const idx_t mask = bit_mask(bit);
57 idx_t old_val = *addr;
58
59 do {
60 const idx_t new_val = old_val | mask;
61 if (new_val == old_val) {
62 return false; // Someone else beat us to it.
63 }
64 const idx_t cur_val = (idx_t) Atomic::cmpxchg_ptr((void*) new_val,
65 (volatile void*) addr,
66 (void*) old_val);
67 if (cur_val == old_val) {
68 return true; // Success.
69 }
70 old_val = cur_val; // The value changed, try again.
71 } while (true);
72 }
73
74 inline bool BitMap::par_clear_bit(idx_t bit) {
75 verify_index(bit);
76 volatile idx_t* const addr = word_addr(bit);
77 const idx_t mask = ~bit_mask(bit);
78 idx_t old_val = *addr;
79
80 do {
81 const idx_t new_val = old_val & mask;
82 if (new_val == old_val) {
83 return false; // Someone else beat us to it.
84 }
85 const idx_t cur_val = (idx_t) Atomic::cmpxchg_ptr((void*) new_val,
86 (volatile void*) addr,
87 (void*) old_val);
88 if (cur_val == old_val) {
89 return true; // Success.
90 }
91 old_val = cur_val; // The value changed, try again.
92 } while (true);
93 }
94
95 inline void BitMap::set_range(idx_t beg, idx_t end, RangeSizeHint hint) {
96 if (hint == small_range && end - beg == 1) {
97 set_bit(beg);
98 } else {
99 if (hint == large_range) {
100 set_large_range(beg, end);
101 } else {
102 set_range(beg, end);
103 }
104 }
105 }
106
107 inline void BitMap::clear_range(idx_t beg, idx_t end, RangeSizeHint hint) {
108 if (hint == small_range && end - beg == 1) {
109 clear_bit(beg);
110 } else {
111 if (hint == large_range) {
112 clear_large_range(beg, end);
113 } else {
114 clear_range(beg, end);
115 }
116 }
117 }
118
119 inline void BitMap::par_set_range(idx_t beg, idx_t end, RangeSizeHint hint) {
120 if (hint == small_range && end - beg == 1) {
121 par_at_put(beg, true);
122 } else {
123 if (hint == large_range) {
124 par_at_put_large_range(beg, end, true);
125 } else {
126 par_at_put_range(beg, end, true);
127 }
128 }
129 }
130
131 inline void BitMap::set_range_of_words(idx_t beg, idx_t end) {
132 bm_word_t* map = _map;
133 for (idx_t i = beg; i < end; ++i) map[i] = ~(uintptr_t)0;
134 }
135
136
137 inline void BitMap::clear_range_of_words(idx_t beg, idx_t end) {
138 bm_word_t* map = _map;
139 for (idx_t i = beg; i < end; ++i) map[i] = 0;
140 }
141
142
143 inline void BitMap::clear() {
144 clear_range_of_words(0, size_in_words());
145 }
146
147
148 inline void BitMap::par_clear_range(idx_t beg, idx_t end, RangeSizeHint hint) {
149 if (hint == small_range && end - beg == 1) {
150 par_at_put(beg, false);
151 } else {
152 if (hint == large_range) {
153 par_at_put_large_range(beg, end, false);
154 } else {
155 par_at_put_range(beg, end, false);
156 }
157 }
158 }
159
160 inline BitMap::idx_t
161 BitMap::get_next_one_offset_inline(idx_t l_offset, idx_t r_offset) const {
162 assert(l_offset <= size(), "BitMap index out of bounds");
163 assert(r_offset <= size(), "BitMap index out of bounds");
164 assert(l_offset <= r_offset, "l_offset > r_offset ?");
165
166 if (l_offset == r_offset) {
167 return l_offset;
168 }
169 idx_t index = word_index(l_offset);
170 idx_t r_index = word_index(r_offset-1) + 1;
171 idx_t res_offset = l_offset;
172
173 // check bits including and to the _left_ of offset's position
174 idx_t pos = bit_in_word(res_offset);
175 idx_t res = map(index) >> pos;
176 if (res != (uintptr_t)NoBits) {
177 // find the position of the 1-bit
178 for (; !(res & 1); res_offset++) {
179 res = res >> 1;
180 }
181
182 #ifdef ASSERT
183 // In the following assert, if r_offset is not bitamp word aligned,
184 // checking that res_offset is strictly less than r_offset is too
185 // strong and will trip the assert.
186 //
187 // Consider the case where l_offset is bit 15 and r_offset is bit 17
188 // of the same map word, and where bits [15:16:17:18] == [00:00:00:01].
189 // All the bits in the range [l_offset:r_offset) are 0.
190 // The loop that calculates res_offset, above, would yield the offset
191 // of bit 18 because it's in the same map word as l_offset and there
192 // is a set bit in that map word above l_offset (i.e. res != NoBits).
193 //
194 // In this case, however, we can assert is that res_offset is strictly
195 // less than size() since we know that there is at least one set bit
196 // at an offset above, but in the same map word as, r_offset.
197 // Otherwise, if r_offset is word aligned then it will not be in the
198 // same map word as l_offset (unless it equals l_offset). So either
199 // there won't be a set bit between l_offset and the end of it's map
200 // word (i.e. res == NoBits), or res_offset will be less than r_offset.
201
202 idx_t limit = is_word_aligned(r_offset) ? r_offset : size();
203 assert(res_offset >= l_offset && res_offset < limit, "just checking");
204 #endif // ASSERT
205 return MIN2(res_offset, r_offset);
206 }
207 // skip over all word length 0-bit runs
208 for (index++; index < r_index; index++) {
209 res = map(index);
210 if (res != (uintptr_t)NoBits) {
211 // found a 1, return the offset
212 for (res_offset = bit_index(index); !(res & 1); res_offset++) {
213 res = res >> 1;
214 }
215 assert(res & 1, "tautology; see loop condition");
216 assert(res_offset >= l_offset, "just checking");
217 return MIN2(res_offset, r_offset);
218 }
219 }
220 return r_offset;
221 }
222
223 inline BitMap::idx_t
224 BitMap::get_next_zero_offset_inline(idx_t l_offset, idx_t r_offset) const {
225 assert(l_offset <= size(), "BitMap index out of bounds");
226 assert(r_offset <= size(), "BitMap index out of bounds");
227 assert(l_offset <= r_offset, "l_offset > r_offset ?");
228
229 if (l_offset == r_offset) {
230 return l_offset;
231 }
232 idx_t index = word_index(l_offset);
233 idx_t r_index = word_index(r_offset-1) + 1;
234 idx_t res_offset = l_offset;
235
236 // check bits including and to the _left_ of offset's position
237 idx_t pos = res_offset & (BitsPerWord - 1);
238 idx_t res = (map(index) >> pos) | left_n_bits((int)pos);
239
240 if (res != (uintptr_t)AllBits) {
241 // find the position of the 0-bit
242 for (; res & 1; res_offset++) {
243 res = res >> 1;
244 }
245 assert(res_offset >= l_offset, "just checking");
246 return MIN2(res_offset, r_offset);
247 }
248 // skip over all word length 1-bit runs
249 for (index++; index < r_index; index++) {
250 res = map(index);
251 if (res != (uintptr_t)AllBits) {
252 // found a 0, return the offset
253 for (res_offset = index << LogBitsPerWord; res & 1;
254 res_offset++) {
255 res = res >> 1;
256 }
257 assert(!(res & 1), "tautology; see loop condition");
258 assert(res_offset >= l_offset, "just checking");
259 return MIN2(res_offset, r_offset);
260 }
261 }
262 return r_offset;
263 }
264
265 inline BitMap::idx_t
266 BitMap::get_next_one_offset_inline_aligned_right(idx_t l_offset,
267 idx_t r_offset) const
268 {
269 verify_range(l_offset, r_offset);
270 assert(bit_in_word(r_offset) == 0, "r_offset not word-aligned");
271
272 if (l_offset == r_offset) {
273 return l_offset;
274 }
275 idx_t index = word_index(l_offset);
276 idx_t r_index = word_index(r_offset);
277 idx_t res_offset = l_offset;
278
279 // check bits including and to the _left_ of offset's position
280 idx_t res = map(index) >> bit_in_word(res_offset);
281 if (res != (uintptr_t)NoBits) {
282 // find the position of the 1-bit
283 for (; !(res & 1); res_offset++) {
284 res = res >> 1;
285 }
286 assert(res_offset >= l_offset &&
287 res_offset < r_offset, "just checking");
288 return res_offset;
289 }
290 // skip over all word length 0-bit runs
291 for (index++; index < r_index; index++) {
292 res = map(index);
293 if (res != (uintptr_t)NoBits) {
294 // found a 1, return the offset
295 for (res_offset = bit_index(index); !(res & 1); res_offset++) {
296 res = res >> 1;
297 }
298 assert(res & 1, "tautology; see loop condition");
299 assert(res_offset >= l_offset && res_offset < r_offset, "just checking");
300 return res_offset;
301 }
302 }
303 return r_offset;
304 }
305
306
307 // Returns a bit mask for a range of bits [beg, end) within a single word. Each
308 // bit in the mask is 0 if the bit is in the range, 1 if not in the range. The
309 // returned mask can be used directly to clear the range, or inverted to set the
310 // range. Note: end must not be 0.
311 inline BitMap::bm_word_t
312 BitMap::inverted_bit_mask_for_range(idx_t beg, idx_t end) const {
313 assert(end != 0, "does not work when end == 0");
314 assert(beg == end || word_index(beg) == word_index(end - 1),
315 "must be a single-word range");
316 bm_word_t mask = bit_mask(beg) - 1; // low (right) bits
317 if (bit_in_word(end) != 0) {
318 mask |= ~(bit_mask(end) - 1); // high (left) bits
319 }
320 return mask;
321 }
322
323 inline void BitMap::set_large_range_of_words(idx_t beg, idx_t end) {
324 memset(_map + beg, ~(unsigned char)0, (end - beg) * sizeof(uintptr_t));
325 }
326
327 inline void BitMap::clear_large_range_of_words(idx_t beg, idx_t end) {
328 memset(_map + beg, 0, (end - beg) * sizeof(uintptr_t));
329 }
330
331 inline BitMap::idx_t BitMap::word_index_round_up(idx_t bit) const {
332 idx_t bit_rounded_up = bit + (BitsPerWord - 1);
333 // Check for integer arithmetic overflow.
334 return bit_rounded_up > bit ? word_index(bit_rounded_up) : size_in_words();
335 }
336
337 inline BitMap::idx_t BitMap::get_next_one_offset(idx_t l_offset,
338 idx_t r_offset) const {
339 return get_next_one_offset_inline(l_offset, r_offset);
340 }
341
342 inline BitMap::idx_t BitMap::get_next_zero_offset(idx_t l_offset,
343 idx_t r_offset) const {
344 return get_next_zero_offset_inline(l_offset, r_offset);
345 }
346
347 inline void BitMap2D::clear() {
348 _map.clear();
349 }
350
351 #endif // SHARE_VM_UTILITIES_BITMAP_INLINE_HPP