1 /*
   2  * Copyright (c) 1997, 2013, 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   assert(end_full_word - beg_full_word >= 32,
 179          "the range must include at least 32 bytes");
 180 
 181   // The range includes at least one full word.
 182   clear_range_within_word(beg, bit_index(beg_full_word));
 183   clear_large_range_of_words(beg_full_word, end_full_word);
 184   clear_range_within_word(bit_index(end_full_word), end);
 185 }
 186 
 187 void BitMap::at_put(idx_t offset, bool value) {
 188   if (value) {
 189     set_bit(offset);
 190   } else {
 191     clear_bit(offset);
 192   }
 193 }
 194 
 195 // Return true to indicate that this thread changed
 196 // the bit, false to indicate that someone else did.
 197 // In either case, the requested bit is in the
 198 // requested state some time during the period that
 199 // this thread is executing this call. More importantly,
 200 // if no other thread is executing an action to
 201 // change the requested bit to a state other than
 202 // the one that this thread is trying to set it to,
 203 // then the the bit is in the expected state
 204 // at exit from this method. However, rather than
 205 // make such a strong assertion here, based on
 206 // assuming such constrained use (which though true
 207 // today, could change in the future to service some
 208 // funky parallel algorithm), we encourage callers
 209 // to do such verification, as and when appropriate.
 210 bool BitMap::par_at_put(idx_t bit, bool value) {
 211   return value ? par_set_bit(bit) : par_clear_bit(bit);
 212 }
 213 
 214 void BitMap::at_put_grow(idx_t offset, bool value) {
 215   if (offset >= size()) {
 216     resize(2 * MAX2(size(), offset));
 217   }
 218   at_put(offset, value);
 219 }
 220 
 221 void BitMap::at_put_range(idx_t start_offset, idx_t end_offset, bool value) {
 222   if (value) {
 223     set_range(start_offset, end_offset);
 224   } else {
 225     clear_range(start_offset, end_offset);
 226   }
 227 }
 228 
 229 void BitMap::par_at_put_range(idx_t beg, idx_t end, bool value) {
 230   verify_range(beg, end);
 231 
 232   idx_t beg_full_word = word_index_round_up(beg);
 233   idx_t end_full_word = word_index(end);
 234 
 235   if (beg_full_word < end_full_word) {
 236     // The range includes at least one full word.
 237     par_put_range_within_word(beg, bit_index(beg_full_word), value);
 238     if (value) {
 239       set_range_of_words(beg_full_word, end_full_word);
 240     } else {
 241       clear_range_of_words(beg_full_word, end_full_word);
 242     }
 243     par_put_range_within_word(bit_index(end_full_word), end, value);
 244   } else {
 245     // The range spans at most 2 partial words.
 246     idx_t boundary = MIN2(bit_index(beg_full_word), end);
 247     par_put_range_within_word(beg, boundary, value);
 248     par_put_range_within_word(boundary, end, value);
 249   }
 250 
 251 }
 252 
 253 void BitMap::at_put_large_range(idx_t beg, idx_t end, bool value) {
 254   if (value) {
 255     set_large_range(beg, end);
 256   } else {
 257     clear_large_range(beg, end);
 258   }
 259 }
 260 
 261 void BitMap::par_at_put_large_range(idx_t beg, idx_t end, bool value) {
 262   verify_range(beg, end);
 263 
 264   idx_t beg_full_word = word_index_round_up(beg);
 265   idx_t end_full_word = word_index(end);
 266 
 267   assert(end_full_word - beg_full_word >= 32,
 268          "the range must include at least 32 bytes");
 269 
 270   // The range includes at least one full word.
 271   par_put_range_within_word(beg, bit_index(beg_full_word), value);
 272   if (value) {
 273     set_large_range_of_words(beg_full_word, end_full_word);
 274   } else {
 275     clear_large_range_of_words(beg_full_word, end_full_word);
 276   }
 277   par_put_range_within_word(bit_index(end_full_word), end, value);
 278 }
 279 
 280 bool BitMap::contains(const BitMap other) const {
 281   assert(size() == other.size(), "must have same size");
 282   bm_word_t* dest_map = map();
 283   bm_word_t* other_map = other.map();
 284   idx_t size = size_in_words();
 285   for (idx_t index = 0; index < size_in_words(); index++) {
 286     bm_word_t word_union = dest_map[index] | other_map[index];
 287     // If this has more bits set than dest_map[index], then other is not a
 288     // subset.
 289     if (word_union != dest_map[index]) return false;
 290   }
 291   return true;
 292 }
 293 
 294 bool BitMap::intersects(const BitMap other) const {
 295   assert(size() == other.size(), "must have same size");
 296   bm_word_t* dest_map = map();
 297   bm_word_t* other_map = other.map();
 298   idx_t size = size_in_words();
 299   for (idx_t index = 0; index < size_in_words(); index++) {
 300     if ((dest_map[index] & other_map[index]) != 0) return true;
 301   }
 302   // Otherwise, no intersection.
 303   return false;
 304 }
 305 
 306 void BitMap::set_union(BitMap other) {
 307   assert(size() == other.size(), "must have same size");
 308   bm_word_t* dest_map = map();
 309   bm_word_t* other_map = other.map();
 310   idx_t size = size_in_words();
 311   for (idx_t index = 0; index < size_in_words(); index++) {
 312     dest_map[index] = dest_map[index] | other_map[index];
 313   }
 314 }
 315 
 316 
 317 void BitMap::set_difference(BitMap other) {
 318   assert(size() == other.size(), "must have same size");
 319   bm_word_t* dest_map = map();
 320   bm_word_t* other_map = other.map();
 321   idx_t size = size_in_words();
 322   for (idx_t index = 0; index < size_in_words(); index++) {
 323     dest_map[index] = dest_map[index] & ~(other_map[index]);
 324   }
 325 }
 326 
 327 
 328 void BitMap::set_intersection(BitMap other) {
 329   assert(size() == other.size(), "must have same size");
 330   bm_word_t* dest_map = map();
 331   bm_word_t* other_map = other.map();
 332   idx_t size = size_in_words();
 333   for (idx_t index = 0; index < size; index++) {
 334     dest_map[index]  = dest_map[index] & other_map[index];
 335   }
 336 }
 337 
 338 
 339 void BitMap::set_intersection_at_offset(BitMap other, idx_t offset) {
 340   assert(other.size() >= offset, "offset not in range");
 341   assert(other.size() - offset >= size(), "other not large enough");
 342   // XXX Ideally, we would remove this restriction.
 343   guarantee((offset % (sizeof(bm_word_t) * BitsPerByte)) == 0,
 344             "Only handle aligned cases so far.");
 345   bm_word_t* dest_map = map();
 346   bm_word_t* other_map = other.map();
 347   idx_t offset_word_ind = word_index(offset);
 348   idx_t size = size_in_words();
 349   for (idx_t index = 0; index < size; index++) {
 350     dest_map[index] = dest_map[index] & other_map[offset_word_ind + index];
 351   }
 352 }
 353 
 354 bool BitMap::set_union_with_result(BitMap other) {
 355   assert(size() == other.size(), "must have same size");
 356   bool changed = false;
 357   bm_word_t* dest_map = map();
 358   bm_word_t* other_map = other.map();
 359   idx_t size = size_in_words();
 360   for (idx_t index = 0; index < size; index++) {
 361     idx_t temp = map(index) | other_map[index];
 362     changed = changed || (temp != map(index));
 363     map()[index] = temp;
 364   }
 365   return changed;
 366 }
 367 
 368 
 369 bool BitMap::set_difference_with_result(BitMap other) {
 370   assert(size() == other.size(), "must have same size");
 371   bool changed = false;
 372   bm_word_t* dest_map = map();
 373   bm_word_t* other_map = other.map();
 374   idx_t size = size_in_words();
 375   for (idx_t index = 0; index < size; index++) {
 376     bm_word_t temp = dest_map[index] & ~(other_map[index]);
 377     changed = changed || (temp != dest_map[index]);
 378     dest_map[index] = temp;
 379   }
 380   return changed;
 381 }
 382 
 383 
 384 bool BitMap::set_intersection_with_result(BitMap other) {
 385   assert(size() == other.size(), "must have same size");
 386   bool changed = false;
 387   bm_word_t* dest_map = map();
 388   bm_word_t* other_map = other.map();
 389   idx_t size = size_in_words();
 390   for (idx_t index = 0; index < size; index++) {
 391     bm_word_t orig = dest_map[index];
 392     bm_word_t temp = orig & other_map[index];
 393     changed = changed || (temp != orig);
 394     dest_map[index]  = temp;
 395   }
 396   return changed;
 397 }
 398 
 399 
 400 void BitMap::set_from(BitMap other) {
 401   assert(size() == other.size(), "must have same size");
 402   bm_word_t* dest_map = map();
 403   bm_word_t* other_map = other.map();
 404   idx_t size = size_in_words();
 405   for (idx_t index = 0; index < size; index++) {
 406     dest_map[index] = other_map[index];
 407   }
 408 }
 409 
 410 
 411 bool BitMap::is_same(BitMap other) {
 412   assert(size() == other.size(), "must have same size");
 413   bm_word_t* dest_map = map();
 414   bm_word_t* other_map = other.map();
 415   idx_t size = size_in_words();
 416   for (idx_t index = 0; index < size; index++) {
 417     if (dest_map[index] != other_map[index]) return false;
 418   }
 419   return true;
 420 }
 421 
 422 bool BitMap::is_full() const {
 423   bm_word_t* word = map();
 424   idx_t rest = size();
 425   for (; rest >= (idx_t) BitsPerWord; rest -= BitsPerWord) {
 426     if (*word != (bm_word_t) AllBits) return false;
 427     word++;
 428   }
 429   return rest == 0 || (*word | ~right_n_bits((int)rest)) == (bm_word_t) AllBits;
 430 }
 431 
 432 
 433 bool BitMap::is_empty() const {
 434   bm_word_t* word = map();
 435   idx_t rest = size();
 436   for (; rest >= (idx_t) BitsPerWord; rest -= BitsPerWord) {
 437     if (*word != (bm_word_t) NoBits) return false;
 438     word++;
 439   }
 440   return rest == 0 || (*word & right_n_bits((int)rest)) == (bm_word_t) NoBits;
 441 }
 442 
 443 void BitMap::clear_large() {
 444   clear_large_range_of_words(0, size_in_words());
 445 }
 446 
 447 // Note that if the closure itself modifies the bitmap
 448 // then modifications in and to the left of the _bit_ being
 449 // currently sampled will not be seen. Note also that the
 450 // interval [leftOffset, rightOffset) is right open.
 451 bool BitMap::iterate(BitMapClosure* blk, idx_t leftOffset, idx_t rightOffset) {
 452   verify_range(leftOffset, rightOffset);
 453 
 454   idx_t startIndex = word_index(leftOffset);
 455   idx_t endIndex   = MIN2(word_index(rightOffset) + 1, size_in_words());
 456   for (idx_t index = startIndex, offset = leftOffset;
 457        offset < rightOffset && index < endIndex;
 458        offset = (++index) << LogBitsPerWord) {
 459     idx_t rest = map(index) >> (offset & (BitsPerWord - 1));
 460     for (; offset < rightOffset && rest != (bm_word_t)NoBits; offset++) {
 461       if (rest & 1) {
 462         if (!blk->do_bit(offset)) return false;
 463         //  resample at each closure application
 464         // (see, for instance, CMS bug 4525989)
 465         rest = map(index) >> (offset & (BitsPerWord -1));
 466       }
 467       rest = rest >> 1;
 468     }
 469   }
 470   return true;
 471 }
 472 
 473 BitMap::idx_t* BitMap::_pop_count_table = NULL;
 474 
 475 void BitMap::init_pop_count_table() {
 476   if (_pop_count_table == NULL) {
 477     BitMap::idx_t *table = NEW_C_HEAP_ARRAY(idx_t, 256, mtInternal);
 478     for (uint i = 0; i < 256; i++) {
 479       table[i] = num_set_bits(i);
 480     }
 481 
 482     intptr_t res = Atomic::cmpxchg_ptr((intptr_t)  table,
 483                                        (intptr_t*) &_pop_count_table,
 484                                        (intptr_t)  NULL_WORD);
 485     if (res != NULL_WORD) {
 486       guarantee( _pop_count_table == (void*) res, "invariant" );
 487       FREE_C_HEAP_ARRAY(bm_word_t, table, mtInternal);
 488     }
 489   }
 490 }
 491 
 492 BitMap::idx_t BitMap::num_set_bits(bm_word_t w) {
 493   idx_t bits = 0;
 494 
 495   while (w != 0) {
 496     while ((w & 1) == 0) {
 497       w >>= 1;
 498     }
 499     bits++;
 500     w >>= 1;
 501   }
 502   return bits;
 503 }
 504 
 505 BitMap::idx_t BitMap::num_set_bits_from_table(unsigned char c) {
 506   assert(_pop_count_table != NULL, "precondition");
 507   return _pop_count_table[c];
 508 }
 509 
 510 BitMap::idx_t BitMap::count_one_bits() const {
 511   init_pop_count_table(); // If necessary.
 512   idx_t sum = 0;
 513   typedef unsigned char uchar;
 514   for (idx_t i = 0; i < size_in_words(); i++) {
 515     bm_word_t w = map()[i];
 516     for (size_t j = 0; j < sizeof(bm_word_t); j++) {
 517       sum += num_set_bits_from_table(uchar(w & 255));
 518       w >>= 8;
 519     }
 520   }
 521   return sum;
 522 }
 523 
 524 void BitMap::print_on_error(outputStream* st, const char* prefix) const {
 525   st->print_cr("%s[" PTR_FORMAT ", " PTR_FORMAT ")",
 526       prefix, map(), (char*)map() + (size() >> LogBitsPerByte));
 527 }
 528 
 529 #ifndef PRODUCT
 530 
 531 void BitMap::print_on(outputStream* st) const {
 532   tty->print("Bitmap(%d):", size());
 533   for (idx_t index = 0; index < size(); index++) {
 534     tty->print("%c", at(index) ? '1' : '0');
 535   }
 536   tty->cr();
 537 }
 538 
 539 #endif
 540 
 541 
 542 BitMap2D::BitMap2D(bm_word_t* map, idx_t size_in_slots, idx_t bits_per_slot)
 543   : _bits_per_slot(bits_per_slot)
 544   , _map(map, size_in_slots * bits_per_slot)
 545 {
 546 }
 547 
 548 
 549 BitMap2D::BitMap2D(idx_t size_in_slots, idx_t bits_per_slot)
 550   : _bits_per_slot(bits_per_slot)
 551   , _map(size_in_slots * bits_per_slot)
 552 {
 553 }