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src/hotspot/share/utilities/bitMap.cpp

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   1 /*
   2  * Copyright (c) 1997, 2018, 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  *


 157     : BitMap(allocate(CHeapBitMapAllocator(flags), size_in_bits, clear), size_in_bits), _flags(flags) {
 158 }
 159 
 160 CHeapBitMap::~CHeapBitMap() {
 161   free(CHeapBitMapAllocator(_flags), map(), size());
 162 }
 163 
 164 void CHeapBitMap::resize(idx_t new_size_in_bits, bool clear) {
 165   BitMap::resize(CHeapBitMapAllocator(_flags), new_size_in_bits, clear);
 166 }
 167 
 168 void CHeapBitMap::initialize(idx_t size_in_bits, bool clear) {
 169   BitMap::initialize(CHeapBitMapAllocator(_flags), size_in_bits, clear);
 170 }
 171 
 172 void CHeapBitMap::reinitialize(idx_t size_in_bits, bool clear) {
 173   BitMap::reinitialize(CHeapBitMapAllocator(_flags), size_in_bits, clear);
 174 }
 175 
 176 #ifdef ASSERT





 177 void BitMap::verify_index(idx_t index) const {
 178   assert(index < _size, "BitMap index out of bounds");
 179 }
 180 
 181 void BitMap::verify_range(idx_t beg_index, idx_t end_index) const {
 182   assert(beg_index <= end_index, "BitMap range error");
 183   // Note that [0,0) and [size,size) are both valid ranges.
 184   if (end_index != _size) verify_index(end_index);
 185 }
 186 #endif // #ifdef ASSERT
 187 
 188 void BitMap::pretouch() {
 189   os::pretouch_memory(word_addr(0), word_addr(size()));
 190 }
 191 
 192 void BitMap::set_range_within_word(idx_t beg, idx_t end) {
 193   // With a valid range (beg <= end), this test ensures that end != 0, as
 194   // required by inverted_bit_mask_for_range.  Also avoids an unnecessary write.
 195   if (beg != end) {
 196     bm_word_t mask = inverted_bit_mask_for_range(beg, end);
 197     *word_addr(beg) |= ~mask;
 198   }
 199 }
 200 
 201 void BitMap::clear_range_within_word(idx_t beg, idx_t end) {
 202   // With a valid range (beg <= end), this test ensures that end != 0, as
 203   // required by inverted_bit_mask_for_range.  Also avoids an unnecessary write.
 204   if (beg != end) {


 211   assert(value == 0 || value == 1, "0 for clear, 1 for set");
 212   // With a valid range (beg <= end), this test ensures that end != 0, as
 213   // required by inverted_bit_mask_for_range.  Also avoids an unnecessary write.
 214   if (beg != end) {
 215     bm_word_t* pw = word_addr(beg);
 216     bm_word_t  w  = *pw;
 217     bm_word_t  mr = inverted_bit_mask_for_range(beg, end);
 218     bm_word_t  nw = value ? (w | ~mr) : (w & mr);
 219     while (true) {
 220       bm_word_t res = Atomic::cmpxchg(nw, pw, w);
 221       if (res == w) break;
 222       w  = res;
 223       nw = value ? (w | ~mr) : (w & mr);
 224     }
 225   }
 226 }
 227 
 228 void BitMap::set_range(idx_t beg, idx_t end) {
 229   verify_range(beg, end);
 230 
 231   idx_t beg_full_word = word_index_round_up(beg);
 232   idx_t end_full_word = word_index(end);
 233 
 234   if (beg_full_word < end_full_word) {
 235     // The range includes at least one full word.
 236     set_range_within_word(beg, bit_index(beg_full_word));
 237     set_range_of_words(beg_full_word, end_full_word);
 238     set_range_within_word(bit_index(end_full_word), end);
 239   } else {
 240     // The range spans at most 2 partial words.
 241     idx_t boundary = MIN2(bit_index(beg_full_word), end);
 242     set_range_within_word(beg, boundary);
 243     set_range_within_word(boundary, end);
 244   }
 245 }
 246 
 247 void BitMap::clear_range(idx_t beg, idx_t end) {
 248   verify_range(beg, end);
 249 
 250   idx_t beg_full_word = word_index_round_up(beg);
 251   idx_t end_full_word = word_index(end);
 252 
 253   if (beg_full_word < end_full_word) {
 254     // The range includes at least one full word.
 255     clear_range_within_word(beg, bit_index(beg_full_word));
 256     clear_range_of_words(beg_full_word, end_full_word);
 257     clear_range_within_word(bit_index(end_full_word), end);
 258   } else {
 259     // The range spans at most 2 partial words.
 260     idx_t boundary = MIN2(bit_index(beg_full_word), end);
 261     clear_range_within_word(beg, boundary);
 262     clear_range_within_word(boundary, end);
 263   }
 264 }
 265 
 266 bool BitMap::is_small_range_of_words(idx_t beg_full_word, idx_t end_full_word) {
 267   // There is little point to call large version on small ranges.
 268   // Need to check carefully, keeping potential idx_t underflow in mind.


 269   // The threshold should be at least one word.
 270   STATIC_ASSERT(small_range_words >= 1);
 271   return (beg_full_word + small_range_words >= end_full_word);
 272 }
 273 
 274 void BitMap::set_large_range(idx_t beg, idx_t end) {
 275   verify_range(beg, end);
 276 
 277   idx_t beg_full_word = word_index_round_up(beg);
 278   idx_t end_full_word = word_index(end);
 279 
 280   if (is_small_range_of_words(beg_full_word, end_full_word)) {
 281     set_range(beg, end);
 282     return;
 283   }
 284 
 285   // The range includes at least one full word.
 286   set_range_within_word(beg, bit_index(beg_full_word));
 287   set_large_range_of_words(beg_full_word, end_full_word);
 288   set_range_within_word(bit_index(end_full_word), end);
 289 }
 290 
 291 void BitMap::clear_large_range(idx_t beg, idx_t end) {
 292   verify_range(beg, end);
 293 
 294   idx_t beg_full_word = word_index_round_up(beg);
 295   idx_t end_full_word = word_index(end);
 296 
 297   if (is_small_range_of_words(beg_full_word, end_full_word)) {
 298     clear_range(beg, end);
 299     return;
 300   }
 301 
 302   // The range includes at least one full word.
 303   clear_range_within_word(beg, bit_index(beg_full_word));
 304   clear_large_range_of_words(beg_full_word, end_full_word);
 305   clear_range_within_word(bit_index(end_full_word), end);
 306 }
 307 
 308 void BitMap::at_put(idx_t offset, bool value) {
 309   if (value) {
 310     set_bit(offset);
 311   } else {
 312     clear_bit(offset);
 313   }
 314 }
 315 
 316 // Return true to indicate that this thread changed
 317 // the bit, false to indicate that someone else did.
 318 // In either case, the requested bit is in the
 319 // requested state some time during the period that
 320 // this thread is executing this call. More importantly,
 321 // if no other thread is executing an action to
 322 // change the requested bit to a state other than
 323 // the one that this thread is trying to set it to,
 324 // then the the bit is in the expected state
 325 // at exit from this method. However, rather than
 326 // make such a strong assertion here, based on
 327 // assuming such constrained use (which though true
 328 // today, could change in the future to service some
 329 // funky parallel algorithm), we encourage callers
 330 // to do such verification, as and when appropriate.
 331 bool BitMap::par_at_put(idx_t bit, bool value) {
 332   return value ? par_set_bit(bit) : par_clear_bit(bit);
 333 }
 334 
 335 void BitMap::at_put_range(idx_t start_offset, idx_t end_offset, bool value) {
 336   if (value) {
 337     set_range(start_offset, end_offset);
 338   } else {
 339     clear_range(start_offset, end_offset);
 340   }
 341 }
 342 
 343 void BitMap::par_at_put_range(idx_t beg, idx_t end, bool value) {
 344   verify_range(beg, end);
 345 
 346   idx_t beg_full_word = word_index_round_up(beg);
 347   idx_t end_full_word = word_index(end);
 348 
 349   if (beg_full_word < end_full_word) {
 350     // The range includes at least one full word.
 351     par_put_range_within_word(beg, bit_index(beg_full_word), value);


 352     if (value) {
 353       set_range_of_words(beg_full_word, end_full_word);
 354     } else {
 355       clear_range_of_words(beg_full_word, end_full_word);
 356     }
 357     par_put_range_within_word(bit_index(end_full_word), end, value);
 358   } else {
 359     // The range spans at most 2 partial words.
 360     idx_t boundary = MIN2(bit_index(beg_full_word), end);
 361     par_put_range_within_word(beg, boundary, value);
 362     par_put_range_within_word(boundary, end, value);
 363   }
 364 
 365 }
 366 
 367 void BitMap::at_put_large_range(idx_t beg, idx_t end, bool value) {
 368   if (value) {
 369     set_large_range(beg, end);
 370   } else {
 371     clear_large_range(beg, end);
 372   }
 373 }
 374 
 375 void BitMap::par_at_put_large_range(idx_t beg, idx_t end, bool value) {
 376   verify_range(beg, end);
 377 
 378   idx_t beg_full_word = word_index_round_up(beg);
 379   idx_t end_full_word = word_index(end);
 380 
 381   if (is_small_range_of_words(beg_full_word, end_full_word)) {
 382     par_at_put_range(beg, end, value);
 383     return;
 384   }
 385 
 386   // The range includes at least one full word.
 387   par_put_range_within_word(beg, bit_index(beg_full_word), value);


 388   if (value) {
 389     set_large_range_of_words(beg_full_word, end_full_word);
 390   } else {
 391     clear_large_range_of_words(beg_full_word, end_full_word);
 392   }
 393   par_put_range_within_word(bit_index(end_full_word), end, value);
 394 }
 395 
 396 inline bm_word_t tail_mask(idx_t tail_bits) {
 397   assert(tail_bits != 0, "precondition"); // Works, but shouldn't be called.
 398   assert(tail_bits < (idx_t)BitsPerWord, "precondition");
 399   return (bm_word_t(1) << tail_bits) - 1;
 400 }
 401 
 402 // Get the low tail_bits of value, which is the last partial word of a map.
 403 inline bm_word_t tail_of_map(bm_word_t value, idx_t tail_bits) {
 404   return value & tail_mask(tail_bits);
 405 }
 406 
 407 // Compute the new last word of a map with a non-aligned length.
 408 // new_value has the new trailing bits of the map in the low tail_bits.
 409 // old_value is the last word of the map, including bits beyond the end.
 410 // Returns old_value with the low tail_bits replaced by the corresponding
 411 // bits in new_value.
 412 inline bm_word_t merge_tail_of_map(bm_word_t new_value,
 413                                    bm_word_t old_value,


   1 /*
   2  * Copyright (c) 1997, 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  *


 157     : BitMap(allocate(CHeapBitMapAllocator(flags), size_in_bits, clear), size_in_bits), _flags(flags) {
 158 }
 159 
 160 CHeapBitMap::~CHeapBitMap() {
 161   free(CHeapBitMapAllocator(_flags), map(), size());
 162 }
 163 
 164 void CHeapBitMap::resize(idx_t new_size_in_bits, bool clear) {
 165   BitMap::resize(CHeapBitMapAllocator(_flags), new_size_in_bits, clear);
 166 }
 167 
 168 void CHeapBitMap::initialize(idx_t size_in_bits, bool clear) {
 169   BitMap::initialize(CHeapBitMapAllocator(_flags), size_in_bits, clear);
 170 }
 171 
 172 void CHeapBitMap::reinitialize(idx_t size_in_bits, bool clear) {
 173   BitMap::reinitialize(CHeapBitMapAllocator(_flags), size_in_bits, clear);
 174 }
 175 
 176 #ifdef ASSERT
 177 void BitMap::verify_valid_size(idx_t size_in_bits) {
 178   assert(size_in_bits <= max_size_in_bits(),
 179          "out of bounds: " SIZE_FORMAT, size_in_bits);
 180 }
 181 
 182 void BitMap::verify_index(idx_t index) const {
 183   assert(index < _size, "BitMap index out of bounds");
 184 }
 185 
 186 void BitMap::verify_range(idx_t beg_index, idx_t end_index) const {
 187   assert(beg_index <= end_index, "BitMap range error");
 188   // Note that [0,0) and [size,size) are both valid ranges.
 189   assert(end_index <= _size, "BitMap range out of bounds");
 190 }
 191 #endif // #ifdef ASSERT
 192 
 193 void BitMap::pretouch() {
 194   os::pretouch_memory(word_addr(0), word_addr(size()));
 195 }
 196 
 197 void BitMap::set_range_within_word(idx_t beg, idx_t end) {
 198   // With a valid range (beg <= end), this test ensures that end != 0, as
 199   // required by inverted_bit_mask_for_range.  Also avoids an unnecessary write.
 200   if (beg != end) {
 201     bm_word_t mask = inverted_bit_mask_for_range(beg, end);
 202     *word_addr(beg) |= ~mask;
 203   }
 204 }
 205 
 206 void BitMap::clear_range_within_word(idx_t beg, idx_t end) {
 207   // With a valid range (beg <= end), this test ensures that end != 0, as
 208   // required by inverted_bit_mask_for_range.  Also avoids an unnecessary write.
 209   if (beg != end) {


 216   assert(value == 0 || value == 1, "0 for clear, 1 for set");
 217   // With a valid range (beg <= end), this test ensures that end != 0, as
 218   // required by inverted_bit_mask_for_range.  Also avoids an unnecessary write.
 219   if (beg != end) {
 220     bm_word_t* pw = word_addr(beg);
 221     bm_word_t  w  = *pw;
 222     bm_word_t  mr = inverted_bit_mask_for_range(beg, end);
 223     bm_word_t  nw = value ? (w | ~mr) : (w & mr);
 224     while (true) {
 225       bm_word_t res = Atomic::cmpxchg(nw, pw, w);
 226       if (res == w) break;
 227       w  = res;
 228       nw = value ? (w | ~mr) : (w & mr);
 229     }
 230   }
 231 }
 232 
 233 void BitMap::set_range(idx_t beg, idx_t end) {
 234   verify_range(beg, end);
 235 
 236   idx_t beg_aligned = range_begin_align_up(beg);
 237   idx_t end_aligned = range_end_align_down(end);
 238 
 239   if (beg_aligned < end_aligned) {
 240     // The range includes at least one full word.
 241     set_range_within_word(beg, beg_aligned);
 242     set_range_of_words(word_index(beg_aligned), word_index(end_aligned));
 243     set_range_within_word(end_aligned, end);
 244   } else {
 245     // The range spans at most 2 partial words.
 246     idx_t boundary = MIN2(beg_aligned, end);
 247     set_range_within_word(beg, boundary);
 248     set_range_within_word(boundary, end);
 249   }
 250 }
 251 
 252 void BitMap::clear_range(idx_t beg, idx_t end) {
 253   verify_range(beg, end);
 254 
 255   idx_t beg_aligned = range_begin_align_up(beg);
 256   idx_t end_aligned = range_end_align_down(end);
 257 
 258   if (beg_aligned < end_aligned) {
 259     // The range includes at least one full word.
 260     clear_range_within_word(beg, beg_aligned);
 261     clear_range_of_words(word_index(beg_aligned), word_index(end_aligned));
 262     clear_range_within_word(end_aligned, end);
 263   } else {
 264     // The range spans at most 2 partial words.
 265     idx_t boundary = MIN2(beg_aligned, end);
 266     clear_range_within_word(beg, boundary);
 267     clear_range_within_word(boundary, end);
 268   }
 269 }
 270 
 271 bool BitMap::is_small_aligned_range(idx_t beg_aligned, idx_t end_aligned) {
 272   // There is little point to call large version on small ranges.
 273   // Need to check carefully, keeping potential idx_t over/underflow in mind,
 274   // because beg_aligned > end_aligned can occur when beg and end are in the
 275   // same word.
 276   // The threshold should be at least one word.
 277   STATIC_ASSERT(small_range_words >= 1);
 278   return word_index(beg_aligned) + small_range_words >= word_index(end_aligned);
 279 }
 280 
 281 void BitMap::set_large_range(idx_t beg, idx_t end) {
 282   verify_range(beg, end);
 283 
 284   idx_t beg_aligned = range_begin_align_up(beg);
 285   idx_t end_aligned = range_end_align_down(end);
 286 
 287   if (is_small_aligned_range(beg_aligned, end_aligned)) {
 288     set_range(beg, end);
 289     return;
 290   }
 291 
 292   // The range includes at least one full word.
 293   set_range_within_word(beg, beg_aligned);
 294   set_large_range_of_words(word_index(beg_aligned), word_index(end_aligned));
 295   set_range_within_word(end_aligned, end);
 296 }
 297 
 298 void BitMap::clear_large_range(idx_t beg, idx_t end) {
 299   verify_range(beg, end);
 300 
 301   idx_t beg_aligned = range_begin_align_up(beg);
 302   idx_t end_aligned = range_end_align_down(end);
 303 
 304   if (is_small_aligned_range(beg_aligned, end_aligned)) {
 305     clear_range(beg, end);
 306     return;
 307   }
 308 
 309   // The range includes at least one full word.
 310   clear_range_within_word(beg, beg_aligned);
 311   clear_large_range_of_words(word_index(beg_aligned), word_index(end_aligned));
 312   clear_range_within_word(end_aligned, end);
 313 }
 314 
 315 void BitMap::at_put(idx_t offset, bool value) {
 316   if (value) {
 317     set_bit(offset);
 318   } else {
 319     clear_bit(offset);
 320   }
 321 }
 322 
 323 // Return true to indicate that this thread changed
 324 // the bit, false to indicate that someone else did.
 325 // In either case, the requested bit is in the
 326 // requested state some time during the period that
 327 // this thread is executing this call. More importantly,
 328 // if no other thread is executing an action to
 329 // change the requested bit to a state other than
 330 // the one that this thread is trying to set it to,
 331 // then the the bit is in the expected state
 332 // at exit from this method. However, rather than
 333 // make such a strong assertion here, based on
 334 // assuming such constrained use (which though true
 335 // today, could change in the future to service some
 336 // funky parallel algorithm), we encourage callers
 337 // to do such verification, as and when appropriate.
 338 bool BitMap::par_at_put(idx_t bit, bool value) {
 339   return value ? par_set_bit(bit) : par_clear_bit(bit);
 340 }
 341 
 342 void BitMap::at_put_range(idx_t start_offset, idx_t end_offset, bool value) {
 343   if (value) {
 344     set_range(start_offset, end_offset);
 345   } else {
 346     clear_range(start_offset, end_offset);
 347   }
 348 }
 349 
 350 void BitMap::par_at_put_range(idx_t beg, idx_t end, bool value) {
 351   verify_range(beg, end);
 352 
 353   idx_t beg_aligned = range_begin_align_up(beg);
 354   idx_t end_aligned = range_end_align_down(end);
 355 
 356   if (beg_aligned < end_aligned) {
 357     // The range includes at least one full word.
 358     par_put_range_within_word(beg, beg_aligned, value);
 359     idx_t beg_full_word = word_index(beg_aligned);
 360     idx_t end_full_word = word_index(end_aligned);
 361     if (value) {
 362       set_range_of_words(beg_full_word, end_full_word);
 363     } else {
 364       clear_range_of_words(beg_full_word, end_full_word);
 365     }
 366     par_put_range_within_word(end_aligned, end, value);
 367   } else {
 368     // The range spans at most 2 partial words.
 369     idx_t boundary = MIN2(beg_aligned, end);
 370     par_put_range_within_word(beg, boundary, value);
 371     par_put_range_within_word(boundary, end, value);
 372   }
 373 
 374 }
 375 
 376 void BitMap::at_put_large_range(idx_t beg, idx_t end, bool value) {
 377   if (value) {
 378     set_large_range(beg, end);
 379   } else {
 380     clear_large_range(beg, end);
 381   }
 382 }
 383 
 384 void BitMap::par_at_put_large_range(idx_t beg, idx_t end, bool value) {
 385   verify_range(beg, end);
 386 
 387   idx_t beg_aligned = range_begin_align_up(beg);
 388   idx_t end_aligned = range_end_align_down(end);
 389 
 390   if (is_small_aligned_range(beg_aligned, end_aligned)) {
 391     par_at_put_range(beg, end, value);
 392     return;
 393   }
 394 
 395   // The range includes at least one full word.
 396   par_put_range_within_word(beg, beg_aligned, value);
 397   idx_t beg_full_word = word_index(beg_aligned);
 398   idx_t end_full_word = word_index(end_aligned);
 399   if (value) {
 400     set_large_range_of_words(beg_full_word, end_full_word);
 401   } else {
 402     clear_large_range_of_words(beg_full_word, end_full_word);
 403   }
 404   par_put_range_within_word(end_aligned, end, value);
 405 }
 406 
 407 inline bm_word_t tail_mask(idx_t tail_bits) {
 408   assert(tail_bits != 0, "precondition"); // Works, but shouldn't be called.
 409   assert(tail_bits < (idx_t)BitsPerWord, "precondition");
 410   return (bm_word_t(1) << tail_bits) - 1;
 411 }
 412 
 413 // Get the low tail_bits of value, which is the last partial word of a map.
 414 inline bm_word_t tail_of_map(bm_word_t value, idx_t tail_bits) {
 415   return value & tail_mask(tail_bits);
 416 }
 417 
 418 // Compute the new last word of a map with a non-aligned length.
 419 // new_value has the new trailing bits of the map in the low tail_bits.
 420 // old_value is the last word of the map, including bits beyond the end.
 421 // Returns old_value with the low tail_bits replaced by the corresponding
 422 // bits in new_value.
 423 inline bm_word_t merge_tail_of_map(bm_word_t new_value,
 424                                    bm_word_t old_value,


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