1 /*
   2  * Copyright (c) 2005, 2017, 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 inline void BitMap::set_bit(idx_t bit) {
  32   verify_index(bit);
  33   *word_addr(bit) |= bit_mask(bit);
  34 }
  35 
  36 inline void BitMap::clear_bit(idx_t bit) {
  37   verify_index(bit);
  38   *word_addr(bit) &= ~bit_mask(bit);
  39 }
  40 
  41 inline bool BitMap::par_set_bit(idx_t bit) {
  42   verify_index(bit);
  43   volatile bm_word_t* const addr = word_addr(bit);
  44   const bm_word_t mask = bit_mask(bit);
  45   bm_word_t old_val = *addr;
  46 
  47   do {
  48     const bm_word_t new_val = old_val | mask;
  49     if (new_val == old_val) {
  50       return false;     // Someone else beat us to it.
  51     }
  52     const bm_word_t cur_val = Atomic::cmpxchg(new_val, addr, old_val);
  53     if (cur_val == old_val) {
  54       return true;      // Success.
  55     }
  56     old_val = cur_val;  // The value changed, try again.
  57   } while (true);
  58 }
  59 
  60 inline bool BitMap::par_clear_bit(idx_t bit) {
  61   verify_index(bit);
  62   volatile bm_word_t* const addr = word_addr(bit);
  63   const bm_word_t mask = ~bit_mask(bit);
  64   bm_word_t old_val = *addr;
  65 
  66   do {
  67     const bm_word_t new_val = old_val & mask;
  68     if (new_val == old_val) {
  69       return false;     // Someone else beat us to it.
  70     }
  71     const bm_word_t cur_val = Atomic::cmpxchg(new_val, addr, old_val);
  72     if (cur_val == old_val) {
  73       return true;      // Success.
  74     }
  75     old_val = cur_val;  // The value changed, try again.
  76   } while (true);
  77 }
  78 
  79 inline void BitMap::set_range(idx_t beg, idx_t end, RangeSizeHint hint) {
  80   if (hint == small_range && end - beg == 1) {
  81     set_bit(beg);
  82   } else {
  83     if (hint == large_range) {
  84       set_large_range(beg, end);
  85     } else {
  86       set_range(beg, end);
  87     }
  88   }
  89 }
  90 
  91 inline void BitMap::clear_range(idx_t beg, idx_t end, RangeSizeHint hint) {
  92   if (end - beg == 1) {
  93     clear_bit(beg);
  94   } else {
  95     if (hint == large_range) {
  96       clear_large_range(beg, end);
  97     } else {
  98       clear_range(beg, end);
  99     }
 100   }
 101 }
 102 
 103 inline void BitMap::par_set_range(idx_t beg, idx_t end, RangeSizeHint hint) {
 104   if (hint == small_range && end - beg == 1) {
 105     par_at_put(beg, true);
 106   } else {
 107     if (hint == large_range) {
 108       par_at_put_large_range(beg, end, true);
 109     } else {
 110       par_at_put_range(beg, end, true);
 111     }
 112   }
 113 }
 114 
 115 inline void BitMap::set_range_of_words(idx_t beg, idx_t end) {
 116   bm_word_t* map = _map;
 117   for (idx_t i = beg; i < end; ++i) map[i] = ~(bm_word_t)0;
 118 }
 119 
 120 inline void BitMap::clear_range_of_words(bm_word_t* map, idx_t beg, idx_t end) {
 121   for (idx_t i = beg; i < end; ++i) map[i] = 0;
 122 }
 123 
 124 inline void BitMap::clear_range_of_words(idx_t beg, idx_t end) {
 125   clear_range_of_words(_map, beg, end);
 126 }
 127 
 128 inline void BitMap::clear() {
 129   clear_range_of_words(0, size_in_words());
 130 }
 131 
 132 inline void BitMap::par_clear_range(idx_t beg, idx_t end, RangeSizeHint hint) {
 133   if (hint == small_range && end - beg == 1) {
 134     par_at_put(beg, false);
 135   } else {
 136     if (hint == large_range) {
 137       par_at_put_large_range(beg, end, false);
 138     } else {
 139       par_at_put_range(beg, end, false);
 140     }
 141   }
 142 }
 143 
 144 inline BitMap::idx_t
 145 BitMap::get_next_one_offset(idx_t l_offset, idx_t r_offset) const {
 146   assert(l_offset <= size(), "BitMap index out of bounds");
 147   assert(r_offset <= size(), "BitMap index out of bounds");
 148   assert(l_offset <= r_offset, "l_offset > r_offset ?");
 149 
 150   if (l_offset == r_offset) {
 151     return l_offset;
 152   }
 153   idx_t   index = word_index(l_offset);
 154   idx_t r_index = word_index(r_offset-1) + 1;
 155   idx_t res_offset = l_offset;
 156 
 157   // check bits including and to the _left_ of offset's position
 158   idx_t pos = bit_in_word(res_offset);
 159   bm_word_t res = map(index) >> pos;
 160   if (res != 0) {
 161     // find the position of the 1-bit
 162     for (; !(res & 1); res_offset++) {
 163       res = res >> 1;
 164     }
 165 
 166 #ifdef ASSERT
 167     // In the following assert, if r_offset is not bitamp word aligned,
 168     // checking that res_offset is strictly less than r_offset is too
 169     // strong and will trip the assert.
 170     //
 171     // Consider the case where l_offset is bit 15 and r_offset is bit 17
 172     // of the same map word, and where bits [15:16:17:18] == [00:00:00:01].
 173     // All the bits in the range [l_offset:r_offset) are 0.
 174     // The loop that calculates res_offset, above, would yield the offset
 175     // of bit 18 because it's in the same map word as l_offset and there
 176     // is a set bit in that map word above l_offset (i.e. res != NoBits).
 177     //
 178     // In this case, however, we can assert is that res_offset is strictly
 179     // less than size() since we know that there is at least one set bit
 180     // at an offset above, but in the same map word as, r_offset.
 181     // Otherwise, if r_offset is word aligned then it will not be in the
 182     // same map word as l_offset (unless it equals l_offset). So either
 183     // there won't be a set bit between l_offset and the end of it's map
 184     // word (i.e. res == NoBits), or res_offset will be less than r_offset.
 185 
 186     idx_t limit = is_word_aligned(r_offset) ? r_offset : size();
 187     assert(res_offset >= l_offset && res_offset < limit, "just checking");
 188 #endif // ASSERT
 189     return MIN2(res_offset, r_offset);
 190   }
 191   // skip over all word length 0-bit runs
 192   for (index++; index < r_index; index++) {
 193     res = map(index);
 194     if (res != 0) {
 195       // found a 1, return the offset
 196       for (res_offset = bit_index(index); !(res & 1); res_offset++) {
 197         res = res >> 1;
 198       }
 199       assert(res & 1, "tautology; see loop condition");
 200       assert(res_offset >= l_offset, "just checking");
 201       return MIN2(res_offset, r_offset);
 202     }
 203   }
 204   return r_offset;
 205 }
 206 
 207 inline BitMap::idx_t
 208 BitMap::get_next_zero_offset(idx_t l_offset, idx_t r_offset) const {
 209   assert(l_offset <= size(), "BitMap index out of bounds");
 210   assert(r_offset <= size(), "BitMap index out of bounds");
 211   assert(l_offset <= r_offset, "l_offset > r_offset ?");
 212 
 213   if (l_offset == r_offset) {
 214     return l_offset;
 215   }
 216   idx_t   index = word_index(l_offset);
 217   idx_t r_index = word_index(r_offset-1) + 1;
 218   idx_t res_offset = l_offset;
 219 
 220   // check bits including and to the _left_ of offset's position
 221   idx_t pos = bit_in_word(res_offset);
 222   bm_word_t res = ~map(index) >> pos; // flip bits and shift for l_offset
 223 
 224   if (res != 0) {
 225     // find the position of the 1-bit
 226     for (; !(res & 1); res_offset++) {
 227       res = res >> 1;
 228     }
 229     assert(res_offset >= l_offset, "just checking");
 230     return MIN2(res_offset, r_offset);
 231   }
 232   // skip over all word length 1-bit runs
 233   for (index++; index < r_index; index++) {
 234     res = map(index);
 235     if (res != ~(bm_word_t)0) {
 236       // found a 0, return the offset
 237       for (res_offset = index << LogBitsPerWord; res & 1;
 238            res_offset++) {
 239         res = res >> 1;
 240       }
 241       assert(!(res & 1), "tautology; see loop condition");
 242       assert(res_offset >= l_offset, "just checking");
 243       return MIN2(res_offset, r_offset);
 244     }
 245   }
 246   return r_offset;
 247 }
 248 
 249 inline BitMap::idx_t
 250 BitMap::get_next_one_offset_aligned_right(idx_t l_offset, idx_t r_offset) const
 251 {
 252   verify_range(l_offset, r_offset);
 253   assert(bit_in_word(r_offset) == 0, "r_offset not word-aligned");
 254 
 255   if (l_offset == r_offset) {
 256     return l_offset;
 257   }
 258   idx_t   index = word_index(l_offset);
 259   idx_t r_index = word_index(r_offset);
 260   idx_t res_offset = l_offset;
 261 
 262   // check bits including and to the _left_ of offset's position
 263   bm_word_t res = map(index) >> bit_in_word(res_offset);
 264   if (res != 0) {
 265     // find the position of the 1-bit
 266     for (; !(res & 1); res_offset++) {
 267       res = res >> 1;
 268     }
 269     assert(res_offset >= l_offset &&
 270            res_offset < r_offset, "just checking");
 271     return res_offset;
 272   }
 273   // skip over all word length 0-bit runs
 274   for (index++; index < r_index; index++) {
 275     res = map(index);
 276     if (res != 0) {
 277       // found a 1, return the offset
 278       for (res_offset = bit_index(index); !(res & 1); res_offset++) {
 279         res = res >> 1;
 280       }
 281       assert(res & 1, "tautology; see loop condition");
 282       assert(res_offset >= l_offset && res_offset < r_offset, "just checking");
 283       return res_offset;
 284     }
 285   }
 286   return r_offset;
 287 }
 288 
 289 
 290 // Returns a bit mask for a range of bits [beg, end) within a single word.  Each
 291 // bit in the mask is 0 if the bit is in the range, 1 if not in the range.  The
 292 // returned mask can be used directly to clear the range, or inverted to set the
 293 // range.  Note:  end must not be 0.
 294 inline BitMap::bm_word_t
 295 BitMap::inverted_bit_mask_for_range(idx_t beg, idx_t end) const {
 296   assert(end != 0, "does not work when end == 0");
 297   assert(beg == end || word_index(beg) == word_index(end - 1),
 298          "must be a single-word range");
 299   bm_word_t mask = bit_mask(beg) - 1;   // low (right) bits
 300   if (bit_in_word(end) != 0) {
 301     mask |= ~(bit_mask(end) - 1);       // high (left) bits
 302   }
 303   return mask;
 304 }
 305 
 306 inline void BitMap::set_large_range_of_words(idx_t beg, idx_t end) {
 307   assert(beg <= end, "underflow");
 308   memset(_map + beg, ~(unsigned char)0, (end - beg) * sizeof(bm_word_t));
 309 }
 310 
 311 inline void BitMap::clear_large_range_of_words(idx_t beg, idx_t end) {
 312   assert(beg <= end, "underflow");
 313   memset(_map + beg, 0, (end - beg) * sizeof(bm_word_t));
 314 }
 315 
 316 inline BitMap::idx_t BitMap::word_index_round_up(idx_t bit) const {
 317   idx_t bit_rounded_up = bit + (BitsPerWord - 1);
 318   // Check for integer arithmetic overflow.
 319   return bit_rounded_up > bit ? word_index(bit_rounded_up) : size_in_words();
 320 }
 321 
 322 inline bool BitMap2D::is_valid_index(idx_t slot_index, idx_t bit_within_slot_index) {
 323   verify_bit_within_slot_index(bit_within_slot_index);
 324   return (bit_index(slot_index, bit_within_slot_index) < size_in_bits());
 325 }
 326 
 327 inline bool BitMap2D::at(idx_t slot_index, idx_t bit_within_slot_index) const {
 328   verify_bit_within_slot_index(bit_within_slot_index);
 329   return _map.at(bit_index(slot_index, bit_within_slot_index));
 330 }
 331 
 332 inline void BitMap2D::set_bit(idx_t slot_index, idx_t bit_within_slot_index) {
 333   verify_bit_within_slot_index(bit_within_slot_index);
 334   _map.set_bit(bit_index(slot_index, bit_within_slot_index));
 335 }
 336 
 337 inline void BitMap2D::clear_bit(idx_t slot_index, idx_t bit_within_slot_index) {
 338   verify_bit_within_slot_index(bit_within_slot_index);
 339   _map.clear_bit(bit_index(slot_index, bit_within_slot_index));
 340 }
 341 
 342 inline void BitMap2D::at_put(idx_t slot_index, idx_t bit_within_slot_index, bool value) {
 343   verify_bit_within_slot_index(bit_within_slot_index);
 344   _map.at_put(bit_index(slot_index, bit_within_slot_index), value);
 345 }
 346 
 347 inline void BitMap2D::at_put_grow(idx_t slot_index, idx_t bit_within_slot_index, bool value) {
 348   verify_bit_within_slot_index(bit_within_slot_index);
 349 
 350   idx_t bit = bit_index(slot_index, bit_within_slot_index);
 351   if (bit >= _map.size()) {
 352     _map.resize(2 * MAX2(_map.size(), bit));
 353   }
 354   _map.at_put(bit, value);
 355 }
 356 
 357 #endif // SHARE_VM_UTILITIES_BITMAP_INLINE_HPP