1 /*
2 * Copyright (c) 2005, 2019, 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_UTILITIES_BITMAP_INLINE_HPP
26 #define SHARE_UTILITIES_BITMAP_INLINE_HPP
27
28 #include "runtime/atomic.hpp"
29 #include "utilities/align.hpp"
30 #include "utilities/bitMap.hpp"
31 #include "utilities/count_trailing_zeros.hpp"
32
33 inline void BitMap::set_bit(idx_t bit) {
34 verify_index(bit);
35 *word_addr(bit) |= bit_mask(bit);
36 }
37
38 inline void BitMap::clear_bit(idx_t bit) {
39 verify_index(bit);
40 *word_addr(bit) &= ~bit_mask(bit);
41 }
42
43 inline bool BitMap::par_set_bit(idx_t bit) {
44 verify_index(bit);
45 volatile bm_word_t* const addr = word_addr(bit);
46 const bm_word_t mask = bit_mask(bit);
47 bm_word_t old_val = *addr;
48
49 do {
50 const bm_word_t new_val = old_val | mask;
51 if (new_val == old_val) {
52 return false; // Someone else beat us to it.
53 }
54 const bm_word_t cur_val = Atomic::cmpxchg(new_val, addr, old_val);
55 if (cur_val == old_val) {
56 return true; // Success.
57 }
58 old_val = cur_val; // The value changed, try again.
59 } while (true);
60 }
61
62 inline bool BitMap::par_clear_bit(idx_t bit) {
63 verify_index(bit);
64 volatile bm_word_t* const addr = word_addr(bit);
65 const bm_word_t mask = ~bit_mask(bit);
66 bm_word_t old_val = *addr;
67
68 do {
69 const bm_word_t new_val = old_val & mask;
70 if (new_val == old_val) {
71 return false; // Someone else beat us to it.
72 }
73 const bm_word_t cur_val = Atomic::cmpxchg(new_val, addr, old_val);
74 if (cur_val == old_val) {
75 return true; // Success.
76 }
77 old_val = cur_val; // The value changed, try again.
78 } while (true);
79 }
80
81 inline void BitMap::set_range(idx_t beg, idx_t end, RangeSizeHint hint) {
82 if (hint == small_range && end - beg == 1) {
83 set_bit(beg);
84 } else {
85 if (hint == large_range) {
86 set_large_range(beg, end);
87 } else {
88 set_range(beg, end);
89 }
90 }
91 }
92
93 inline void BitMap::clear_range(idx_t beg, idx_t end, RangeSizeHint hint) {
94 if (end - beg == 1) {
95 clear_bit(beg);
96 } else {
97 if (hint == large_range) {
98 clear_large_range(beg, end);
99 } else {
100 clear_range(beg, end);
101 }
102 }
103 }
104
105 inline void BitMap::par_set_range(idx_t beg, idx_t end, RangeSizeHint hint) {
106 if (hint == small_range && end - beg == 1) {
107 par_at_put(beg, true);
108 } else {
109 if (hint == large_range) {
110 par_at_put_large_range(beg, end, true);
111 } else {
112 par_at_put_range(beg, end, true);
113 }
114 }
115 }
116
117 inline void BitMap::set_range_of_words(idx_t beg, idx_t end) {
118 bm_word_t* map = _map;
119 for (idx_t i = beg; i < end; ++i) map[i] = ~(bm_word_t)0;
120 }
121
122 inline void BitMap::clear_range_of_words(bm_word_t* map, idx_t beg, idx_t end) {
123 for (idx_t i = beg; i < end; ++i) map[i] = 0;
124 }
125
126 inline void BitMap::clear_range_of_words(idx_t beg, idx_t end) {
127 clear_range_of_words(_map, beg, end);
128 }
129
130 inline void BitMap::clear() {
131 clear_range_of_words(0, size_in_words());
132 }
133
134 inline void BitMap::par_clear_range(idx_t beg, idx_t end, RangeSizeHint hint) {
135 if (hint == small_range && end - beg == 1) {
136 par_at_put(beg, false);
137 } else {
138 if (hint == large_range) {
139 par_at_put_large_range(beg, end, false);
140 } else {
141 par_at_put_range(beg, end, false);
142 }
143 }
144 }
145
146 template<BitMap::bm_word_t flip, bool aligned_right>
147 inline BitMap::idx_t BitMap::get_next_bit_impl(idx_t l_index, idx_t r_index) const {
148 STATIC_ASSERT(flip == find_ones_flip || flip == find_zeros_flip);
149 verify_range(l_index, r_index);
150 assert(!aligned_right || is_aligned(r_index, BitsPerWord), "r_index not aligned");
151
152 // The first word often contains an interesting bit, either due to
153 // density or because of features of the calling algorithm. So it's
154 // important to examine that first word with a minimum of fuss,
155 // minimizing setup time for later words that will be wasted if the
156 // first word is indeed interesting.
157
158 // The benefit from aligned_right being true is relatively small.
159 // It saves a couple instructions in the setup for the word search
160 // loop. It also eliminates the range check on the final result.
161 // However, callers often have a comparison with r_index, and
162 // inlining often allows the two comparisons to be combined; it is
163 // important when !aligned_right that return paths either return
164 // r_index or a value dominated by a comparison with r_index.
165 // aligned_right is still helpful when the caller doesn't have a
166 // range check because features of the calling algorithm guarantee
167 // an interesting bit will be present.
168
169 if (l_index < r_index) {
170 // Get the word containing l_index, and shift out low bits.
171 idx_t index = word_index(l_index);
172 bm_word_t cword = (map(index) ^ flip) >> bit_in_word(l_index);
173 if ((cword & 1) != 0) {
174 // The first bit is similarly often interesting. When it matters
175 // (density or features of the calling algorithm make it likely
176 // the first bit is set), going straight to the next clause compares
177 // poorly with doing this check first; count_trailing_zeros can be
178 // relatively expensive, plus there is the additional range check.
179 // But when the first bit isn't set, the cost of having tested for
180 // it is relatively small compared to the rest of the search.
181 return l_index;
182 } else if (cword != 0) {
183 // Flipped and shifted first word is non-zero.
184 idx_t result = l_index + count_trailing_zeros(cword);
185 if (aligned_right || (result < r_index)) return result;
186 // Result is beyond range bound; return r_index.
187 } else {
188 // Flipped and shifted first word is zero. Word search through
189 // aligned up r_index for a non-zero flipped word.
190 idx_t limit = aligned_right
191 ? word_index(r_index)
192 : (word_index(r_index - 1) + 1); // Align up, knowing r_index > 0.
193 while (++index < limit) {
194 cword = map(index) ^ flip;
195 if (cword != 0) {
196 idx_t result = bit_index(index) + count_trailing_zeros(cword);
197 if (aligned_right || (result < r_index)) return result;
198 // Result is beyond range bound; return r_index.
199 assert((index + 1) == limit, "invariant");
200 break;
201 }
202 }
203 // No bits in range; return r_index.
204 }
205 }
206 return r_index;
207 }
208
209 inline BitMap::idx_t
210 BitMap::get_next_one_offset(idx_t l_offset, idx_t r_offset) const {
211 return get_next_bit_impl<find_ones_flip, false>(l_offset, r_offset);
212 }
213
214 inline BitMap::idx_t
215 BitMap::get_next_zero_offset(idx_t l_offset, idx_t r_offset) const {
216 return get_next_bit_impl<find_zeros_flip, false>(l_offset, r_offset);
217 }
218
219 inline BitMap::idx_t
220 BitMap::get_next_one_offset_aligned_right(idx_t l_offset, idx_t r_offset) const {
221 return get_next_bit_impl<find_ones_flip, true>(l_offset, r_offset);
222 }
223
224 // Returns a bit mask for a range of bits [beg, end) within a single word. Each
225 // bit in the mask is 0 if the bit is in the range, 1 if not in the range. The
226 // returned mask can be used directly to clear the range, or inverted to set the
227 // range. Note: end must not be 0.
228 inline BitMap::bm_word_t
229 BitMap::inverted_bit_mask_for_range(idx_t beg, idx_t end) const {
230 assert(end != 0, "does not work when end == 0");
231 assert(beg == end || word_index(beg) == word_index(end - 1),
232 "must be a single-word range");
233 bm_word_t mask = bit_mask(beg) - 1; // low (right) bits
234 if (bit_in_word(end) != 0) {
235 mask |= ~(bit_mask(end) - 1); // high (left) bits
236 }
237 return mask;
238 }
239
240 inline void BitMap::set_large_range_of_words(idx_t beg, idx_t end) {
241 assert(beg <= end, "underflow");
242 memset(_map + beg, ~(unsigned char)0, (end - beg) * sizeof(bm_word_t));
243 }
244
245 inline void BitMap::clear_large_range_of_words(idx_t beg, idx_t end) {
246 assert(beg <= end, "underflow");
247 memset(_map + beg, 0, (end - beg) * sizeof(bm_word_t));
248 }
249
250 inline BitMap::idx_t BitMap::range_begin_align_up(idx_t bit) {
251 return align_up(bit, BitsPerWord);
252 }
253
254 inline BitMap::idx_t BitMap::range_end_align_down(idx_t bit) {
255 return align_down(bit, BitsPerWord);
256 }
257
258 inline bool BitMap2D::is_valid_index(idx_t slot_index, idx_t bit_within_slot_index) {
259 verify_bit_within_slot_index(bit_within_slot_index);
260 return (bit_index(slot_index, bit_within_slot_index) < size_in_bits());
261 }
262
263 inline bool BitMap2D::at(idx_t slot_index, idx_t bit_within_slot_index) const {
264 verify_bit_within_slot_index(bit_within_slot_index);
265 return _map.at(bit_index(slot_index, bit_within_slot_index));
266 }
267
268 inline void BitMap2D::set_bit(idx_t slot_index, idx_t bit_within_slot_index) {
269 verify_bit_within_slot_index(bit_within_slot_index);
270 _map.set_bit(bit_index(slot_index, bit_within_slot_index));
271 }
272
273 inline void BitMap2D::clear_bit(idx_t slot_index, idx_t bit_within_slot_index) {
274 verify_bit_within_slot_index(bit_within_slot_index);
275 _map.clear_bit(bit_index(slot_index, bit_within_slot_index));
276 }
277
278 inline void BitMap2D::at_put(idx_t slot_index, idx_t bit_within_slot_index, bool value) {
279 verify_bit_within_slot_index(bit_within_slot_index);
280 _map.at_put(bit_index(slot_index, bit_within_slot_index), value);
281 }
282
283 inline void BitMap2D::at_put_grow(idx_t slot_index, idx_t bit_within_slot_index, bool value) {
284 verify_bit_within_slot_index(bit_within_slot_index);
285
286 idx_t bit = bit_index(slot_index, bit_within_slot_index);
287 if (bit >= _map.size()) {
288 _map.resize(2 * MAX2(_map.size(), bit));
289 }
290 _map.at_put(bit, value);
291 }
292
293 #endif // SHARE_UTILITIES_BITMAP_INLINE_HPP