1 /*
   2  * Copyright (c) 1997, 2014, 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 #include "precompiled.hpp"
  26 #include "memory/allocation.inline.hpp"
  27 #include "utilities/bitMap.inline.hpp"
  28 #include "utilities/copy.hpp"
  29 #ifdef TARGET_OS_FAMILY_linux
  30 # include "os_linux.inline.hpp"
  31 #endif
  32 #ifdef TARGET_OS_FAMILY_solaris
  33 # include "os_solaris.inline.hpp"
  34 #endif
  35 #ifdef TARGET_OS_FAMILY_windows
  36 # include "os_windows.inline.hpp"
  37 #endif
  38 #ifdef TARGET_OS_FAMILY_aix
  39 # include "os_aix.inline.hpp"
  40 #endif
  41 #ifdef TARGET_OS_FAMILY_bsd
  42 # include "os_bsd.inline.hpp"
  43 #endif
  44 
  45 
  46 BitMap::BitMap(bm_word_t* map, idx_t size_in_bits) :
  47   _map(map), _size(size_in_bits), _map_allocator(false)
  48 {
  49   assert(sizeof(bm_word_t) == BytesPerWord, "Implementation assumption.");
  50   assert(size_in_bits >= 0, "just checking");
  51 }
  52 
  53 
  54 BitMap::BitMap(idx_t size_in_bits, bool in_resource_area) :
  55   _map(NULL), _size(0), _map_allocator(false)
  56 {
  57   assert(sizeof(bm_word_t) == BytesPerWord, "Implementation assumption.");
  58   resize(size_in_bits, in_resource_area);
  59 }
  60 
  61 void BitMap::resize(idx_t size_in_bits, bool in_resource_area) {
  62   assert(size_in_bits >= 0, "just checking");
  63   idx_t old_size_in_words = size_in_words();
  64   bm_word_t* old_map = map();
  65 
  66   _size = size_in_bits;
  67   idx_t new_size_in_words = size_in_words();
  68   if (in_resource_area) {
  69     _map = NEW_RESOURCE_ARRAY(bm_word_t, new_size_in_words);
  70   } else {
  71     if (old_map != NULL) {
  72       _map_allocator.free();
  73     }
  74     _map = _map_allocator.allocate(new_size_in_words);
  75   }
  76   Copy::disjoint_words((HeapWord*)old_map, (HeapWord*) _map,
  77                        MIN2(old_size_in_words, new_size_in_words));
  78   if (new_size_in_words > old_size_in_words) {
  79     clear_range_of_words(old_size_in_words, size_in_words());
  80   }
  81 }
  82 
  83 void BitMap::set_range_within_word(idx_t beg, idx_t end) {
  84   // With a valid range (beg <= end), this test ensures that end != 0, as
  85   // required by inverted_bit_mask_for_range.  Also avoids an unnecessary write.
  86   if (beg != end) {
  87     bm_word_t mask = inverted_bit_mask_for_range(beg, end);
  88     *word_addr(beg) |= ~mask;
  89   }
  90 }
  91 
  92 void BitMap::clear_range_within_word(idx_t beg, idx_t end) {
  93   // With a valid range (beg <= end), this test ensures that end != 0, as
  94   // required by inverted_bit_mask_for_range.  Also avoids an unnecessary write.
  95   if (beg != end) {
  96     bm_word_t mask = inverted_bit_mask_for_range(beg, end);
  97     *word_addr(beg) &= mask;
  98   }
  99 }
 100 
 101 void BitMap::par_put_range_within_word(idx_t beg, idx_t end, bool value) {
 102   assert(value == 0 || value == 1, "0 for clear, 1 for set");
 103   // With a valid range (beg <= end), this test ensures that end != 0, as
 104   // required by inverted_bit_mask_for_range.  Also avoids an unnecessary write.
 105   if (beg != end) {
 106     intptr_t* pw  = (intptr_t*)word_addr(beg);
 107     intptr_t  w   = *pw;
 108     intptr_t  mr  = (intptr_t)inverted_bit_mask_for_range(beg, end);
 109     intptr_t  nw  = value ? (w | ~mr) : (w & mr);
 110     while (true) {
 111       intptr_t res = Atomic::cmpxchg_ptr(nw, pw, w);
 112       if (res == w) break;
 113       w  = res;
 114       nw = value ? (w | ~mr) : (w & mr);
 115     }
 116   }
 117 }
 118 
 119 void BitMap::set_range(idx_t beg, idx_t end) {
 120   verify_range(beg, end);
 121 
 122   idx_t beg_full_word = word_index_round_up(beg);
 123   idx_t end_full_word = word_index(end);
 124 
 125   if (beg_full_word < end_full_word) {
 126     // The range includes at least one full word.
 127     set_range_within_word(beg, bit_index(beg_full_word));
 128     set_range_of_words(beg_full_word, end_full_word);
 129     set_range_within_word(bit_index(end_full_word), end);
 130   } else {
 131     // The range spans at most 2 partial words.
 132     idx_t boundary = MIN2(bit_index(beg_full_word), end);
 133     set_range_within_word(beg, boundary);
 134     set_range_within_word(boundary, end);
 135   }
 136 }
 137 
 138 void BitMap::clear_range(idx_t beg, idx_t end) {
 139   verify_range(beg, end);
 140 
 141   idx_t beg_full_word = word_index_round_up(beg);
 142   idx_t end_full_word = word_index(end);
 143 
 144   if (beg_full_word < end_full_word) {
 145     // The range includes at least one full word.
 146     clear_range_within_word(beg, bit_index(beg_full_word));
 147     clear_range_of_words(beg_full_word, end_full_word);
 148     clear_range_within_word(bit_index(end_full_word), end);
 149   } else {
 150     // The range spans at most 2 partial words.
 151     idx_t boundary = MIN2(bit_index(beg_full_word), end);
 152     clear_range_within_word(beg, boundary);
 153     clear_range_within_word(boundary, end);
 154   }
 155 }
 156 
 157 void BitMap::set_large_range(idx_t beg, idx_t end) {
 158   verify_range(beg, end);
 159 
 160   idx_t beg_full_word = word_index_round_up(beg);
 161   idx_t end_full_word = word_index(end);
 162 
 163   assert(end_full_word - beg_full_word >= 32,
 164          "the range must include at least 32 bytes");
 165 
 166   // The range includes at least one full word.
 167   set_range_within_word(beg, bit_index(beg_full_word));
 168   set_large_range_of_words(beg_full_word, end_full_word);
 169   set_range_within_word(bit_index(end_full_word), end);
 170 }
 171 
 172 void BitMap::clear_large_range(idx_t beg, idx_t end) {
 173   verify_range(beg, end);
 174 
 175   idx_t beg_full_word = word_index_round_up(beg);
 176   idx_t end_full_word = word_index(end);
 177 
 178   if (end_full_word - beg_full_word < 32) {
 179     clear_range(beg, end);
 180   }
 181 
 182   // The range includes at least one full word.
 183   clear_range_within_word(beg, bit_index(beg_full_word));
 184   clear_large_range_of_words(beg_full_word, end_full_word);
 185   clear_range_within_word(bit_index(end_full_word), end);
 186 }
 187 
 188 void BitMap::at_put(idx_t offset, bool value) {
 189   if (value) {
 190     set_bit(offset);
 191   } else {
 192     clear_bit(offset);
 193   }
 194 }
 195 
 196 // Return true to indicate that this thread changed
 197 // the bit, false to indicate that someone else did.
 198 // In either case, the requested bit is in the
 199 // requested state some time during the period that
 200 // this thread is executing this call. More importantly,
 201 // if no other thread is executing an action to
 202 // change the requested bit to a state other than
 203 // the one that this thread is trying to set it to,
 204 // then the the bit is in the expected state
 205 // at exit from this method. However, rather than
 206 // make such a strong assertion here, based on
 207 // assuming such constrained use (which though true
 208 // today, could change in the future to service some
 209 // funky parallel algorithm), we encourage callers
 210 // to do such verification, as and when appropriate.
 211 bool BitMap::par_at_put(idx_t bit, bool value) {
 212   return value ? par_set_bit(bit) : par_clear_bit(bit);
 213 }
 214 
 215 void BitMap::at_put_grow(idx_t offset, bool value) {
 216   if (offset >= size()) {
 217     resize(2 * MAX2(size(), offset));
 218   }
 219   at_put(offset, value);
 220 }
 221 
 222 void BitMap::at_put_range(idx_t start_offset, idx_t end_offset, bool value) {
 223   if (value) {
 224     set_range(start_offset, end_offset);
 225   } else {
 226     clear_range(start_offset, end_offset);
 227   }
 228 }
 229 
 230 void BitMap::par_at_put_range(idx_t beg, idx_t end, bool value) {
 231   verify_range(beg, end);
 232 
 233   idx_t beg_full_word = word_index_round_up(beg);
 234   idx_t end_full_word = word_index(end);
 235 
 236   if (beg_full_word < end_full_word) {
 237     // The range includes at least one full word.
 238     par_put_range_within_word(beg, bit_index(beg_full_word), value);
 239     if (value) {
 240       set_range_of_words(beg_full_word, end_full_word);
 241     } else {
 242       clear_range_of_words(beg_full_word, end_full_word);
 243     }
 244     par_put_range_within_word(bit_index(end_full_word), end, value);
 245   } else {
 246     // The range spans at most 2 partial words.
 247     idx_t boundary = MIN2(bit_index(beg_full_word), end);
 248     par_put_range_within_word(beg, boundary, value);
 249     par_put_range_within_word(boundary, end, value);
 250   }
 251 
 252 }
 253 
 254 void BitMap::at_put_large_range(idx_t beg, idx_t end, bool value) {
 255   if (value) {
 256     set_large_range(beg, end);
 257   } else {
 258     clear_large_range(beg, end);
 259   }
 260 }
 261 
 262 void BitMap::par_at_put_large_range(idx_t beg, idx_t end, bool value) {
 263   verify_range(beg, end);
 264 
 265   idx_t beg_full_word = word_index_round_up(beg);
 266   idx_t end_full_word = word_index(end);
 267 
 268   assert(end_full_word - beg_full_word >= 32,
 269          "the range must include at least 32 bytes");
 270 
 271   // The range includes at least one full word.
 272   par_put_range_within_word(beg, bit_index(beg_full_word), value);
 273   if (value) {
 274     set_large_range_of_words(beg_full_word, end_full_word);
 275   } else {
 276     clear_large_range_of_words(beg_full_word, end_full_word);
 277   }
 278   par_put_range_within_word(bit_index(end_full_word), end, value);
 279 }
 280 
 281 bool BitMap::contains(const BitMap other) const {
 282   assert(size() == other.size(), "must have same size");
 283   bm_word_t* dest_map = map();
 284   bm_word_t* other_map = other.map();
 285   idx_t size = size_in_words();
 286   for (idx_t index = 0; index < size_in_words(); index++) {
 287     bm_word_t word_union = dest_map[index] | other_map[index];
 288     // If this has more bits set than dest_map[index], then other is not a
 289     // subset.
 290     if (word_union != dest_map[index]) return false;
 291   }
 292   return true;
 293 }
 294 
 295 bool BitMap::intersects(const BitMap other) const {
 296   assert(size() == other.size(), "must have same size");
 297   bm_word_t* dest_map = map();
 298   bm_word_t* other_map = other.map();
 299   idx_t size = size_in_words();
 300   for (idx_t index = 0; index < size_in_words(); index++) {
 301     if ((dest_map[index] & other_map[index]) != 0) return true;
 302   }
 303   // Otherwise, no intersection.
 304   return false;
 305 }
 306 
 307 void BitMap::set_union(BitMap other) {
 308   assert(size() == other.size(), "must have same size");
 309   bm_word_t* dest_map = map();
 310   bm_word_t* other_map = other.map();
 311   idx_t size = size_in_words();
 312   for (idx_t index = 0; index < size_in_words(); index++) {
 313     dest_map[index] = dest_map[index] | other_map[index];
 314   }
 315 }
 316 
 317 
 318 void BitMap::set_difference(BitMap other) {
 319   assert(size() == other.size(), "must have same size");
 320   bm_word_t* dest_map = map();
 321   bm_word_t* other_map = other.map();
 322   idx_t size = size_in_words();
 323   for (idx_t index = 0; index < size_in_words(); index++) {
 324     dest_map[index] = dest_map[index] & ~(other_map[index]);
 325   }
 326 }
 327 
 328 
 329 void BitMap::set_intersection(BitMap other) {
 330   assert(size() == other.size(), "must have same size");
 331   bm_word_t* dest_map = map();
 332   bm_word_t* other_map = other.map();
 333   idx_t size = size_in_words();
 334   for (idx_t index = 0; index < size; index++) {
 335     dest_map[index]  = dest_map[index] & other_map[index];
 336   }
 337 }
 338 
 339 
 340 void BitMap::set_intersection_at_offset(BitMap other, idx_t offset) {
 341   assert(other.size() >= offset, "offset not in range");
 342   assert(other.size() - offset >= size(), "other not large enough");
 343   // XXX Ideally, we would remove this restriction.
 344   guarantee((offset % (sizeof(bm_word_t) * BitsPerByte)) == 0,
 345             "Only handle aligned cases so far.");
 346   bm_word_t* dest_map = map();
 347   bm_word_t* other_map = other.map();
 348   idx_t offset_word_ind = word_index(offset);
 349   idx_t size = size_in_words();
 350   for (idx_t index = 0; index < size; index++) {
 351     dest_map[index] = dest_map[index] & other_map[offset_word_ind + index];
 352   }
 353 }
 354 
 355 bool BitMap::set_union_with_result(BitMap other) {
 356   assert(size() == other.size(), "must have same size");
 357   bool changed = false;
 358   bm_word_t* dest_map = map();
 359   bm_word_t* other_map = other.map();
 360   idx_t size = size_in_words();
 361   for (idx_t index = 0; index < size; index++) {
 362     idx_t temp = map(index) | other_map[index];
 363     changed = changed || (temp != map(index));
 364     map()[index] = temp;
 365   }
 366   return changed;
 367 }
 368 
 369 
 370 bool BitMap::set_difference_with_result(BitMap other) {
 371   assert(size() == other.size(), "must have same size");
 372   bool changed = false;
 373   bm_word_t* dest_map = map();
 374   bm_word_t* other_map = other.map();
 375   idx_t size = size_in_words();
 376   for (idx_t index = 0; index < size; index++) {
 377     bm_word_t temp = dest_map[index] & ~(other_map[index]);
 378     changed = changed || (temp != dest_map[index]);
 379     dest_map[index] = temp;
 380   }
 381   return changed;
 382 }
 383 
 384 
 385 bool BitMap::set_intersection_with_result(BitMap other) {
 386   assert(size() == other.size(), "must have same size");
 387   bool changed = false;
 388   bm_word_t* dest_map = map();
 389   bm_word_t* other_map = other.map();
 390   idx_t size = size_in_words();
 391   for (idx_t index = 0; index < size; index++) {
 392     bm_word_t orig = dest_map[index];
 393     bm_word_t temp = orig & other_map[index];
 394     changed = changed || (temp != orig);
 395     dest_map[index]  = temp;
 396   }
 397   return changed;
 398 }
 399 
 400 
 401 void BitMap::set_from(BitMap other) {
 402   assert(size() == other.size(), "must have same size");
 403   bm_word_t* dest_map = map();
 404   bm_word_t* other_map = other.map();
 405   idx_t size = size_in_words();
 406   for (idx_t index = 0; index < size; index++) {
 407     dest_map[index] = other_map[index];
 408   }
 409 }
 410 
 411 
 412 bool BitMap::is_same(BitMap other) {
 413   assert(size() == other.size(), "must have same size");
 414   bm_word_t* dest_map = map();
 415   bm_word_t* other_map = other.map();
 416   idx_t size = size_in_words();
 417   for (idx_t index = 0; index < size; index++) {
 418     if (dest_map[index] != other_map[index]) return false;
 419   }
 420   return true;
 421 }
 422 
 423 bool BitMap::is_full() const {
 424   bm_word_t* word = map();
 425   idx_t rest = size();
 426   for (; rest >= (idx_t) BitsPerWord; rest -= BitsPerWord) {
 427     if (*word != (bm_word_t) AllBits) return false;
 428     word++;
 429   }
 430   return rest == 0 || (*word | ~right_n_bits((int)rest)) == (bm_word_t) AllBits;
 431 }
 432 
 433 
 434 bool BitMap::is_empty() const {
 435   bm_word_t* word = map();
 436   idx_t rest = size();
 437   for (; rest >= (idx_t) BitsPerWord; rest -= BitsPerWord) {
 438     if (*word != (bm_word_t) NoBits) return false;
 439     word++;
 440   }
 441   return rest == 0 || (*word & right_n_bits((int)rest)) == (bm_word_t) NoBits;
 442 }
 443 
 444 void BitMap::clear_large() {
 445   clear_large_range_of_words(0, size_in_words());
 446 }
 447 
 448 // Note that if the closure itself modifies the bitmap
 449 // then modifications in and to the left of the _bit_ being
 450 // currently sampled will not be seen. Note also that the
 451 // interval [leftOffset, rightOffset) is right open.
 452 bool BitMap::iterate(BitMapClosure* blk, idx_t leftOffset, idx_t rightOffset) {
 453   verify_range(leftOffset, rightOffset);
 454 
 455   idx_t startIndex = word_index(leftOffset);
 456   idx_t endIndex   = MIN2(word_index(rightOffset) + 1, size_in_words());
 457   for (idx_t index = startIndex, offset = leftOffset;
 458        offset < rightOffset && index < endIndex;
 459        offset = (++index) << LogBitsPerWord) {
 460     idx_t rest = map(index) >> (offset & (BitsPerWord - 1));
 461     for (; offset < rightOffset && rest != (bm_word_t)NoBits; offset++) {
 462       if (rest & 1) {
 463         if (!blk->do_bit(offset)) return false;
 464         //  resample at each closure application
 465         // (see, for instance, CMS bug 4525989)
 466         rest = map(index) >> (offset & (BitsPerWord -1));
 467       }
 468       rest = rest >> 1;
 469     }
 470   }
 471   return true;
 472 }
 473 
 474 BitMap::idx_t* BitMap::_pop_count_table = NULL;
 475 
 476 void BitMap::init_pop_count_table() {
 477   if (_pop_count_table == NULL) {
 478     BitMap::idx_t *table = NEW_C_HEAP_ARRAY(idx_t, 256, mtInternal);
 479     for (uint i = 0; i < 256; i++) {
 480       table[i] = num_set_bits(i);
 481     }
 482 
 483     intptr_t res = Atomic::cmpxchg_ptr((intptr_t)  table,
 484                                        (intptr_t*) &_pop_count_table,
 485                                        (intptr_t)  NULL_WORD);
 486     if (res != NULL_WORD) {
 487       guarantee( _pop_count_table == (void*) res, "invariant" );
 488       FREE_C_HEAP_ARRAY(bm_word_t, table, mtInternal);
 489     }
 490   }
 491 }
 492 
 493 BitMap::idx_t BitMap::num_set_bits(bm_word_t w) {
 494   idx_t bits = 0;
 495 
 496   while (w != 0) {
 497     while ((w & 1) == 0) {
 498       w >>= 1;
 499     }
 500     bits++;
 501     w >>= 1;
 502   }
 503   return bits;
 504 }
 505 
 506 BitMap::idx_t BitMap::num_set_bits_from_table(unsigned char c) {
 507   assert(_pop_count_table != NULL, "precondition");
 508   return _pop_count_table[c];
 509 }
 510 
 511 BitMap::idx_t BitMap::count_one_bits() const {
 512   init_pop_count_table(); // If necessary.
 513   idx_t sum = 0;
 514   typedef unsigned char uchar;
 515   for (idx_t i = 0; i < size_in_words(); i++) {
 516     bm_word_t w = map()[i];
 517     for (size_t j = 0; j < sizeof(bm_word_t); j++) {
 518       sum += num_set_bits_from_table(uchar(w & 255));
 519       w >>= 8;
 520     }
 521   }
 522   return sum;
 523 }
 524 
 525 void BitMap::print_on_error(outputStream* st, const char* prefix) const {
 526   st->print_cr("%s[" PTR_FORMAT ", " PTR_FORMAT ")",
 527       prefix, p2i(map()), p2i((char*)map() + (size() >> LogBitsPerByte)));
 528 }
 529 
 530 #ifndef PRODUCT
 531 
 532 void BitMap::print_on(outputStream* st) const {
 533   tty->print("Bitmap(" SIZE_FORMAT "):", size());
 534   for (idx_t index = 0; index < size(); index++) {
 535     tty->print("%c", at(index) ? '1' : '0');
 536   }
 537   tty->cr();
 538 }
 539 
 540 #endif
 541 
 542 
 543 BitMap2D::BitMap2D(bm_word_t* map, idx_t size_in_slots, idx_t bits_per_slot)
 544   : _bits_per_slot(bits_per_slot)
 545   , _map(map, size_in_slots * bits_per_slot)
 546 {
 547 }
 548 
 549 
 550 BitMap2D::BitMap2D(idx_t size_in_slots, idx_t bits_per_slot)
 551   : _bits_per_slot(bits_per_slot)
 552   , _map(size_in_slots * bits_per_slot)
 553 {
 554 }