hotspot/src/share/vm/utilities/bitMap.cpp - platform/libcore - Git at Google

 /*
  * Copyright 1997-2006 Sun Microsystems, Inc.  All Rights Reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  * CA 95054 USA or visit www.sun.com if you need additional information or
  * have any questions.
  *
  */

 # include "incls/_precompiled.incl"
 # include "incls/_bitMap.cpp.incl"


 BitMap::BitMap(idx_t* map, idx_t size_in_bits) {
   assert(size_in_bits >= 0, "just checking");
   _map = map;
   _size = size_in_bits;
 }


 BitMap::BitMap(idx_t size_in_bits) {
   assert(size_in_bits >= 0, "just checking");
   _size = size_in_bits;
   _map = NEW_RESOURCE_ARRAY(idx_t, size_in_words());
 }


 void BitMap::resize(idx_t size_in_bits) {
   assert(size_in_bits >= 0, "just checking");
   size_t old_size_in_words = size_in_words();
   uintptr_t* old_map = map();
   _size = size_in_bits;
   size_t new_size_in_words = size_in_words();
   _map = NEW_RESOURCE_ARRAY(idx_t, new_size_in_words);
   Copy::disjoint_words((HeapWord*) old_map, (HeapWord*) _map, MIN2(old_size_in_words, new_size_in_words));
   if (new_size_in_words > old_size_in_words) {
     clear_range_of_words(old_size_in_words, size_in_words());
   }
 }

 // Returns a bit mask for a range of bits [beg, end) within a single word.  Each
 // bit in the mask is 0 if the bit is in the range, 1 if not in the range.  The
 // returned mask can be used directly to clear the range, or inverted to set the
 // range.  Note:  end must not be 0.
 inline BitMap::idx_t
 BitMap::inverted_bit_mask_for_range(idx_t beg, idx_t end) const {
   assert(end != 0, "does not work when end == 0");
   assert(beg == end || word_index(beg) == word_index(end - 1),
          "must be a single-word range");
   idx_t mask = bit_mask(beg) - 1;       // low (right) bits
   if (bit_in_word(end) != 0) {
     mask |= ~(bit_mask(end) - 1);       // high (left) bits
   }
   return mask;
 }

 void BitMap::set_range_within_word(idx_t beg, idx_t end) {
   // With a valid range (beg <= end), this test ensures that end != 0, as
   // required by inverted_bit_mask_for_range.  Also avoids an unnecessary write.
   if (beg != end) {
     idx_t mask = inverted_bit_mask_for_range(beg, end);
     *word_addr(beg) |= ~mask;
   }
 }

 void BitMap::clear_range_within_word(idx_t beg, idx_t end) {
   // With a valid range (beg <= end), this test ensures that end != 0, as
   // required by inverted_bit_mask_for_range.  Also avoids an unnecessary write.
   if (beg != end) {
     idx_t mask = inverted_bit_mask_for_range(beg, end);
     *word_addr(beg) &= mask;
   }
 }

 void BitMap::par_put_range_within_word(idx_t beg, idx_t end, bool value) {
   assert(value == 0 || value == 1, "0 for clear, 1 for set");
   // With a valid range (beg <= end), this test ensures that end != 0, as
   // required by inverted_bit_mask_for_range.  Also avoids an unnecessary write.
   if (beg != end) {
     intptr_t* pw  = (intptr_t*)word_addr(beg);
     intptr_t  w   = *pw;
     intptr_t  mr  = (intptr_t)inverted_bit_mask_for_range(beg, end);
     intptr_t  nw  = value ? (w | ~mr) : (w & mr);
     while (true) {
       intptr_t res = Atomic::cmpxchg_ptr(nw, pw, w);
       if (res == w) break;
       w  = *pw;
       nw = value ? (w | ~mr) : (w & mr);
     }
   }
 }

 inline void BitMap::set_large_range_of_words(idx_t beg, idx_t end) {
   memset(_map + beg, ~(unsigned char)0, (end - beg) * sizeof(uintptr_t));
 }

 inline void BitMap::clear_large_range_of_words(idx_t beg, idx_t end) {
   memset(_map + beg, 0, (end - beg) * sizeof(uintptr_t));
 }

 inline BitMap::idx_t BitMap::word_index_round_up(idx_t bit) const {
   idx_t bit_rounded_up = bit + (BitsPerWord - 1);
   // Check for integer arithmetic overflow.
   return bit_rounded_up > bit ? word_index(bit_rounded_up) : size_in_words();
 }

 void BitMap::set_range(idx_t beg, idx_t end) {
   verify_range(beg, end);

   idx_t beg_full_word = word_index_round_up(beg);
   idx_t end_full_word = word_index(end);

   if (beg_full_word < end_full_word) {
     // The range includes at least one full word.
     set_range_within_word(beg, bit_index(beg_full_word));
     set_range_of_words(beg_full_word, end_full_word);
     set_range_within_word(bit_index(end_full_word), end);
   } else {
     // The range spans at most 2 partial words.
     idx_t boundary = MIN2(bit_index(beg_full_word), end);
     set_range_within_word(beg, boundary);
     set_range_within_word(boundary, end);
   }
 }

 void BitMap::clear_range(idx_t beg, idx_t end) {
   verify_range(beg, end);

   idx_t beg_full_word = word_index_round_up(beg);
   idx_t end_full_word = word_index(end);

   if (beg_full_word < end_full_word) {
     // The range includes at least one full word.
     clear_range_within_word(beg, bit_index(beg_full_word));
     clear_range_of_words(beg_full_word, end_full_word);
     clear_range_within_word(bit_index(end_full_word), end);
   } else {
     // The range spans at most 2 partial words.
     idx_t boundary = MIN2(bit_index(beg_full_word), end);
     clear_range_within_word(beg, boundary);
     clear_range_within_word(boundary, end);
   }
 }

 void BitMap::set_large_range(idx_t beg, idx_t end) {
   verify_range(beg, end);

   idx_t beg_full_word = word_index_round_up(beg);
   idx_t end_full_word = word_index(end);

   assert(end_full_word - beg_full_word >= 32,
          "the range must include at least 32 bytes");

   // The range includes at least one full word.
   set_range_within_word(beg, bit_index(beg_full_word));
   set_large_range_of_words(beg_full_word, end_full_word);
   set_range_within_word(bit_index(end_full_word), end);
 }

 void BitMap::clear_large_range(idx_t beg, idx_t end) {
   verify_range(beg, end);

   idx_t beg_full_word = word_index_round_up(beg);
   idx_t end_full_word = word_index(end);

   assert(end_full_word - beg_full_word >= 32,
          "the range must include at least 32 bytes");

   // The range includes at least one full word.
   clear_range_within_word(beg, bit_index(beg_full_word));
   clear_large_range_of_words(beg_full_word, end_full_word);
   clear_range_within_word(bit_index(end_full_word), end);
 }

 void BitMap::at_put(idx_t offset, bool value) {
   if (value) {
     set_bit(offset);
   } else {
     clear_bit(offset);
   }
 }

 // Return true to indicate that this thread changed
 // the bit, false to indicate that someone else did.
 // In either case, the requested bit is in the
 // requested state some time during the period that
 // this thread is executing this call. More importantly,
 // if no other thread is executing an action to
 // change the requested bit to a state other than
 // the one that this thread is trying to set it to,
 // then the the bit is in the expected state
 // at exit from this method. However, rather than
 // make such a strong assertion here, based on
 // assuming such constrained use (which though true
 // today, could change in the future to service some
 // funky parallel algorithm), we encourage callers
 // to do such verification, as and when appropriate.
 bool BitMap::par_at_put(idx_t bit, bool value) {
   return value ? par_set_bit(bit) : par_clear_bit(bit);
 }

 void BitMap::at_put_grow(idx_t offset, bool value) {
   if (offset >= size()) {
     resize(2 * MAX2(size(), offset));
   }
   at_put(offset, value);
 }

 void BitMap::at_put_range(idx_t start_offset, idx_t end_offset, bool value) {
   if (value) {
     set_range(start_offset, end_offset);
   } else {
     clear_range(start_offset, end_offset);
   }
 }

 void BitMap::par_at_put_range(idx_t beg, idx_t end, bool value) {
   verify_range(beg, end);

   idx_t beg_full_word = word_index_round_up(beg);
   idx_t end_full_word = word_index(end);

   if (beg_full_word < end_full_word) {
     // The range includes at least one full word.
     par_put_range_within_word(beg, bit_index(beg_full_word), value);
     if (value) {
       set_range_of_words(beg_full_word, end_full_word);
     } else {
       clear_range_of_words(beg_full_word, end_full_word);
     }
     par_put_range_within_word(bit_index(end_full_word), end, value);
   } else {
     // The range spans at most 2 partial words.
     idx_t boundary = MIN2(bit_index(beg_full_word), end);
     par_put_range_within_word(beg, boundary, value);
     par_put_range_within_word(boundary, end, value);
   }

 }

 void BitMap::at_put_large_range(idx_t beg, idx_t end, bool value) {
   if (value) {
     set_large_range(beg, end);
   } else {
     clear_large_range(beg, end);
   }
 }

 void BitMap::par_at_put_large_range(idx_t beg, idx_t end, bool value) {
   verify_range(beg, end);

   idx_t beg_full_word = word_index_round_up(beg);
   idx_t end_full_word = word_index(end);

   assert(end_full_word - beg_full_word >= 32,
          "the range must include at least 32 bytes");

   // The range includes at least one full word.
   par_put_range_within_word(beg, bit_index(beg_full_word), value);
   if (value) {
     set_large_range_of_words(beg_full_word, end_full_word);
   } else {
     clear_large_range_of_words(beg_full_word, end_full_word);
   }
   par_put_range_within_word(bit_index(end_full_word), end, value);
 }

 bool BitMap::contains(const BitMap other) const {
   assert(size() == other.size(), "must have same size");
   uintptr_t* dest_map = map();
   uintptr_t* other_map = other.map();
   idx_t size = size_in_words();
   for (idx_t index = 0; index < size_in_words(); index++) {
     uintptr_t word_union = dest_map[index] | other_map[index];
     // If this has more bits set than dest_map[index], then other is not a
     // subset.
     if (word_union != dest_map[index]) return false;
   }
   return true;
 }

 bool BitMap::intersects(const BitMap other) const {
   assert(size() == other.size(), "must have same size");
   uintptr_t* dest_map = map();
   uintptr_t* other_map = other.map();
   idx_t size = size_in_words();
   for (idx_t index = 0; index < size_in_words(); index++) {
     if ((dest_map[index] & other_map[index]) != 0) return true;
   }
   // Otherwise, no intersection.
   return false;
 }

 void BitMap::set_union(BitMap other) {
   assert(size() == other.size(), "must have same size");
   idx_t* dest_map = map();
   idx_t* other_map = other.map();
   idx_t size = size_in_words();
   for (idx_t index = 0; index < size_in_words(); index++) {
     dest_map[index] = dest_map[index] | other_map[index];
   }
 }


 void BitMap::set_difference(BitMap other) {
   assert(size() == other.size(), "must have same size");
   idx_t* dest_map = map();
   idx_t* other_map = other.map();
   idx_t size = size_in_words();
   for (idx_t index = 0; index < size_in_words(); index++) {
     dest_map[index] = dest_map[index] & ~(other_map[index]);
   }
 }


 void BitMap::set_intersection(BitMap other) {
   assert(size() == other.size(), "must have same size");
   idx_t* dest_map = map();
   idx_t* other_map = other.map();
   idx_t size = size_in_words();
   for (idx_t index = 0; index < size; index++) {
     dest_map[index]  = dest_map[index] & other_map[index];
   }
 }


 bool BitMap::set_union_with_result(BitMap other) {
   assert(size() == other.size(), "must have same size");
   bool changed = false;
   idx_t* dest_map = map();
   idx_t* other_map = other.map();
   idx_t size = size_in_words();
   for (idx_t index = 0; index < size; index++) {
     idx_t temp = map(index) | other_map[index];
     changed = changed || (temp != map(index));
     map()[index] = temp;
   }
   return changed;
 }


 bool BitMap::set_difference_with_result(BitMap other) {
   assert(size() == other.size(), "must have same size");
   bool changed = false;
   idx_t* dest_map = map();
   idx_t* other_map = other.map();
   idx_t size = size_in_words();
   for (idx_t index = 0; index < size; index++) {
     idx_t temp = dest_map[index] & ~(other_map[index]);
     changed = changed || (temp != dest_map[index]);
     dest_map[index] = temp;
   }
   return changed;
 }


 bool BitMap::set_intersection_with_result(BitMap other) {
   assert(size() == other.size(), "must have same size");
   bool changed = false;
   idx_t* dest_map = map();
   idx_t* other_map = other.map();
   idx_t size = size_in_words();
   for (idx_t index = 0; index < size; index++) {
     idx_t orig = dest_map[index];
     idx_t temp = orig & other_map[index];
     changed = changed || (temp != orig);
     dest_map[index]  = temp;
   }
   return changed;
 }


 void BitMap::set_from(BitMap other) {
   assert(size() == other.size(), "must have same size");
   idx_t* dest_map = map();
   idx_t* other_map = other.map();
   idx_t size = size_in_words();
   for (idx_t index = 0; index < size; index++) {
     dest_map[index] = other_map[index];
   }
 }


 bool BitMap::is_same(BitMap other) {
   assert(size() == other.size(), "must have same size");
   idx_t* dest_map = map();
   idx_t* other_map = other.map();
   idx_t size = size_in_words();
   for (idx_t index = 0; index < size; index++) {
     if (dest_map[index] != other_map[index]) return false;
   }
   return true;
 }

 bool BitMap::is_full() const {
   uintptr_t* word = map();
   idx_t rest = size();
   for (; rest >= (idx_t) BitsPerWord; rest -= BitsPerWord) {
     if (*word != (uintptr_t) AllBits) return false;
     word++;
   }
   return rest == 0 || (*word | ~right_n_bits((int)rest)) == (uintptr_t) AllBits;
 }


 bool BitMap::is_empty() const {
   uintptr_t* word = map();
   idx_t rest = size();
   for (; rest >= (idx_t) BitsPerWord; rest -= BitsPerWord) {
     if (*word != (uintptr_t) NoBits) return false;
     word++;
   }
   return rest == 0 || (*word & right_n_bits((int)rest)) == (uintptr_t) NoBits;
 }

 void BitMap::clear_large() {
   clear_large_range_of_words(0, size_in_words());
 }

 // Note that if the closure itself modifies the bitmap
 // then modifications in and to the left of the _bit_ being
 // currently sampled will not be seen. Note also that the
 // interval [leftOffset, rightOffset) is right open.
 void BitMap::iterate(BitMapClosure* blk, idx_t leftOffset, idx_t rightOffset) {
   verify_range(leftOffset, rightOffset);

   idx_t startIndex = word_index(leftOffset);
   idx_t endIndex   = MIN2(word_index(rightOffset) + 1, size_in_words());
   for (idx_t index = startIndex, offset = leftOffset;
        offset < rightOffset && index < endIndex;
        offset = (++index) << LogBitsPerWord) {
     idx_t rest = map(index) >> (offset & (BitsPerWord - 1));
     for (; offset < rightOffset && rest != (uintptr_t)NoBits; offset++) {
       if (rest & 1) {
         blk->do_bit(offset);
         //  resample at each closure application
         // (see, for instance, CMS bug 4525989)
         rest = map(index) >> (offset & (BitsPerWord -1));
         // XXX debugging: remove
         // The following assertion assumes that closure application
         // doesn't clear bits (may not be true in general, e.g. G1).
         assert(rest & 1,
                "incorrect shift or closure application can clear bits?");
       }
       rest = rest >> 1;
     }
   }
 }

 BitMap::idx_t BitMap::get_next_one_offset(idx_t l_offset,
                                           idx_t r_offset) const {
   assert(l_offset <= size(), "BitMap index out of bounds");
   assert(r_offset <= size(), "BitMap index out of bounds");
   assert(l_offset <= r_offset, "l_offset > r_offset ?");

   if (l_offset == r_offset) {
     return l_offset;
   }
   idx_t   index = word_index(l_offset);
   idx_t r_index = word_index(r_offset-1) + 1;
   idx_t res_offset = l_offset;

   // check bits including and to the _left_ of offset's position
   idx_t pos = bit_in_word(res_offset);
   idx_t res = map(index) >> pos;
   if (res != (uintptr_t)NoBits) {
     // find the position of the 1-bit
     for (; !(res & 1); res_offset++) {
       res = res >> 1;
     }
     assert(res_offset >= l_offset, "just checking");
     return MIN2(res_offset, r_offset);
   }
   // skip over all word length 0-bit runs
   for (index++; index < r_index; index++) {
     res = map(index);
     if (res != (uintptr_t)NoBits) {
       // found a 1, return the offset
       for (res_offset = index << LogBitsPerWord; !(res & 1);
            res_offset++) {
         res = res >> 1;
       }
       assert(res & 1, "tautology; see loop condition");
       assert(res_offset >= l_offset, "just checking");
       return MIN2(res_offset, r_offset);
     }
   }
   return r_offset;
 }

 BitMap::idx_t BitMap::get_next_zero_offset(idx_t l_offset,
                                            idx_t r_offset) const {
   assert(l_offset <= size(), "BitMap index out of bounds");
   assert(r_offset <= size(), "BitMap index out of bounds");
   assert(l_offset <= r_offset, "l_offset > r_offset ?");

   if (l_offset == r_offset) {
     return l_offset;
   }
   idx_t   index = word_index(l_offset);
   idx_t r_index = word_index(r_offset-1) + 1;
   idx_t res_offset = l_offset;

   // check bits including and to the _left_ of offset's position
   idx_t pos = res_offset & (BitsPerWord - 1);
   idx_t res = (map(index) >> pos) | left_n_bits((int)pos);

   if (res != (uintptr_t)AllBits) {
     // find the position of the 0-bit
     for (; res & 1; res_offset++) {
       res = res >> 1;
     }
     assert(res_offset >= l_offset, "just checking");
     return MIN2(res_offset, r_offset);
   }
   // skip over all word length 1-bit runs
   for (index++; index < r_index; index++) {
     res = map(index);
     if (res != (uintptr_t)AllBits) {
       // found a 0, return the offset
       for (res_offset = index << LogBitsPerWord; res & 1;
            res_offset++) {
         res = res >> 1;
       }
       assert(!(res & 1), "tautology; see loop condition");
       assert(res_offset >= l_offset, "just checking");
       return MIN2(res_offset, r_offset);
     }
   }
   return r_offset;
 }

 #ifndef PRODUCT

 void BitMap::print_on(outputStream* st) const {
   tty->print("Bitmap(%d):", size());
   for (idx_t index = 0; index < size(); index++) {
     tty->print("%c", at(index) ? '1' : '0');
   }
   tty->cr();
 }

 #endif


 BitMap2D::BitMap2D(uintptr_t* map, idx_t size_in_slots, idx_t bits_per_slot)
   : _bits_per_slot(bits_per_slot)
   , _map(map, size_in_slots * bits_per_slot)
 {
 }


 BitMap2D::BitMap2D(idx_t size_in_slots, idx_t bits_per_slot)
   : _bits_per_slot(bits_per_slot)
   , _map(size_in_slots * bits_per_slot)
 {
 }
	/*
	* Copyright 1997-2006 Sun Microsystems, Inc. All Rights Reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
	* CA 95054 USA or visit www.sun.com if you need additional information or
	* have any questions.
	*
	*/

	# include "incls/_precompiled.incl"
	# include "incls/_bitMap.cpp.incl"


	BitMap::BitMap(idx_t* map, idx_t size_in_bits) {
	assert(size_in_bits >= 0, "just checking");
	_map = map;
	_size = size_in_bits;
	}


	BitMap::BitMap(idx_t size_in_bits) {
	assert(size_in_bits >= 0, "just checking");
	_size = size_in_bits;
	_map = NEW_RESOURCE_ARRAY(idx_t, size_in_words());
	}


	void BitMap::resize(idx_t size_in_bits) {
	assert(size_in_bits >= 0, "just checking");
	size_t old_size_in_words = size_in_words();
	uintptr_t* old_map = map();
	_size = size_in_bits;
	size_t new_size_in_words = size_in_words();
	_map = NEW_RESOURCE_ARRAY(idx_t, new_size_in_words);
	Copy::disjoint_words((HeapWord) old_map, (HeapWord) _map, MIN2(old_size_in_words, new_size_in_words));
	if (new_size_in_words > old_size_in_words) {
	clear_range_of_words(old_size_in_words, size_in_words());
	}
	}

	// Returns a bit mask for a range of bits [beg, end) within a single word. Each
	// bit in the mask is 0 if the bit is in the range, 1 if not in the range. The
	// returned mask can be used directly to clear the range, or inverted to set the
	// range. Note: end must not be 0.
	inline BitMap::idx_t
	BitMap::inverted_bit_mask_for_range(idx_t beg, idx_t end) const {
	assert(end != 0, "does not work when end == 0");
	assert(beg == end \|\| word_index(beg) == word_index(end - 1),
	"must be a single-word range");
	idx_t mask = bit_mask(beg) - 1; // low (right) bits
	if (bit_in_word(end) != 0) {
	mask \|= ~(bit_mask(end) - 1); // high (left) bits
	}
	return mask;
	}

	void BitMap::set_range_within_word(idx_t beg, idx_t end) {
	// With a valid range (beg <= end), this test ensures that end != 0, as
	// required by inverted_bit_mask_for_range. Also avoids an unnecessary write.
	if (beg != end) {
	idx_t mask = inverted_bit_mask_for_range(beg, end);
	*word_addr(beg) \|= ~mask;
	}
	}

	void BitMap::clear_range_within_word(idx_t beg, idx_t end) {
	// With a valid range (beg <= end), this test ensures that end != 0, as
	// required by inverted_bit_mask_for_range. Also avoids an unnecessary write.
	if (beg != end) {
	idx_t mask = inverted_bit_mask_for_range(beg, end);
	*word_addr(beg) &= mask;
	}
	}

	void BitMap::par_put_range_within_word(idx_t beg, idx_t end, bool value) {
	assert(value == 0 \|\| value == 1, "0 for clear, 1 for set");
	// With a valid range (beg <= end), this test ensures that end != 0, as
	// required by inverted_bit_mask_for_range. Also avoids an unnecessary write.
	if (beg != end) {
	intptr_t* pw = (intptr_t*)word_addr(beg);
	intptr_t w = *pw;
	intptr_t mr = (intptr_t)inverted_bit_mask_for_range(beg, end);
	intptr_t nw = value ? (w \| ~mr) : (w & mr);
	while (true) {
	intptr_t res = Atomic::cmpxchg_ptr(nw, pw, w);
	if (res == w) break;
	w = *pw;
	nw = value ? (w \| ~mr) : (w & mr);
	}
	}
	}

	inline void BitMap::set_large_range_of_words(idx_t beg, idx_t end) {
	memset(_map + beg, ~(unsigned char)0, (end - beg) * sizeof(uintptr_t));
	}

	inline void BitMap::clear_large_range_of_words(idx_t beg, idx_t end) {
	memset(_map + beg, 0, (end - beg) * sizeof(uintptr_t));
	}

	inline BitMap::idx_t BitMap::word_index_round_up(idx_t bit) const {
	idx_t bit_rounded_up = bit + (BitsPerWord - 1);
	// Check for integer arithmetic overflow.
	return bit_rounded_up > bit ? word_index(bit_rounded_up) : size_in_words();
	}

	void BitMap::set_range(idx_t beg, idx_t end) {
	verify_range(beg, end);

	idx_t beg_full_word = word_index_round_up(beg);
	idx_t end_full_word = word_index(end);

	if (beg_full_word < end_full_word) {
	// The range includes at least one full word.
	set_range_within_word(beg, bit_index(beg_full_word));
	set_range_of_words(beg_full_word, end_full_word);
	set_range_within_word(bit_index(end_full_word), end);
	} else {
	// The range spans at most 2 partial words.
	idx_t boundary = MIN2(bit_index(beg_full_word), end);
	set_range_within_word(beg, boundary);
	set_range_within_word(boundary, end);
	}
	}

	void BitMap::clear_range(idx_t beg, idx_t end) {
	verify_range(beg, end);

	idx_t beg_full_word = word_index_round_up(beg);
	idx_t end_full_word = word_index(end);

	if (beg_full_word < end_full_word) {
	// The range includes at least one full word.
	clear_range_within_word(beg, bit_index(beg_full_word));
	clear_range_of_words(beg_full_word, end_full_word);
	clear_range_within_word(bit_index(end_full_word), end);
	} else {
	// The range spans at most 2 partial words.
	idx_t boundary = MIN2(bit_index(beg_full_word), end);
	clear_range_within_word(beg, boundary);
	clear_range_within_word(boundary, end);
	}
	}

	void BitMap::set_large_range(idx_t beg, idx_t end) {
	verify_range(beg, end);

	idx_t beg_full_word = word_index_round_up(beg);
	idx_t end_full_word = word_index(end);

	assert(end_full_word - beg_full_word >= 32,
	"the range must include at least 32 bytes");

	// The range includes at least one full word.
	set_range_within_word(beg, bit_index(beg_full_word));
	set_large_range_of_words(beg_full_word, end_full_word);
	set_range_within_word(bit_index(end_full_word), end);
	}

	void BitMap::clear_large_range(idx_t beg, idx_t end) {
	verify_range(beg, end);

	idx_t beg_full_word = word_index_round_up(beg);
	idx_t end_full_word = word_index(end);

	assert(end_full_word - beg_full_word >= 32,
	"the range must include at least 32 bytes");

	// The range includes at least one full word.
	clear_range_within_word(beg, bit_index(beg_full_word));
	clear_large_range_of_words(beg_full_word, end_full_word);
	clear_range_within_word(bit_index(end_full_word), end);
	}

	void BitMap::at_put(idx_t offset, bool value) {
	if (value) {
	set_bit(offset);
	} else {
	clear_bit(offset);
	}
	}

	// Return true to indicate that this thread changed
	// the bit, false to indicate that someone else did.
	// In either case, the requested bit is in the
	// requested state some time during the period that
	// this thread is executing this call. More importantly,
	// if no other thread is executing an action to
	// change the requested bit to a state other than
	// the one that this thread is trying to set it to,
	// then the the bit is in the expected state
	// at exit from this method. However, rather than
	// make such a strong assertion here, based on
	// assuming such constrained use (which though true
	// today, could change in the future to service some
	// funky parallel algorithm), we encourage callers
	// to do such verification, as and when appropriate.
	bool BitMap::par_at_put(idx_t bit, bool value) {
	return value ? par_set_bit(bit) : par_clear_bit(bit);
	}

	void BitMap::at_put_grow(idx_t offset, bool value) {
	if (offset >= size()) {
	resize(2 * MAX2(size(), offset));
	}
	at_put(offset, value);
	}

	void BitMap::at_put_range(idx_t start_offset, idx_t end_offset, bool value) {
	if (value) {
	set_range(start_offset, end_offset);
	} else {
	clear_range(start_offset, end_offset);
	}
	}

	void BitMap::par_at_put_range(idx_t beg, idx_t end, bool value) {
	verify_range(beg, end);

	idx_t beg_full_word = word_index_round_up(beg);
	idx_t end_full_word = word_index(end);

	if (beg_full_word < end_full_word) {
	// The range includes at least one full word.
	par_put_range_within_word(beg, bit_index(beg_full_word), value);
	if (value) {
	set_range_of_words(beg_full_word, end_full_word);
	} else {
	clear_range_of_words(beg_full_word, end_full_word);
	}
	par_put_range_within_word(bit_index(end_full_word), end, value);
	} else {
	// The range spans at most 2 partial words.
	idx_t boundary = MIN2(bit_index(beg_full_word), end);
	par_put_range_within_word(beg, boundary, value);
	par_put_range_within_word(boundary, end, value);
	}

	}

	void BitMap::at_put_large_range(idx_t beg, idx_t end, bool value) {
	if (value) {
	set_large_range(beg, end);
	} else {
	clear_large_range(beg, end);
	}
	}

	void BitMap::par_at_put_large_range(idx_t beg, idx_t end, bool value) {
	verify_range(beg, end);

	idx_t beg_full_word = word_index_round_up(beg);
	idx_t end_full_word = word_index(end);

	assert(end_full_word - beg_full_word >= 32,
	"the range must include at least 32 bytes");

	// The range includes at least one full word.
	par_put_range_within_word(beg, bit_index(beg_full_word), value);
	if (value) {
	set_large_range_of_words(beg_full_word, end_full_word);
	} else {
	clear_large_range_of_words(beg_full_word, end_full_word);
	}
	par_put_range_within_word(bit_index(end_full_word), end, value);
	}

	bool BitMap::contains(const BitMap other) const {
	assert(size() == other.size(), "must have same size");
	uintptr_t* dest_map = map();
	uintptr_t* other_map = other.map();
	idx_t size = size_in_words();
	for (idx_t index = 0; index < size_in_words(); index++) {
	uintptr_t word_union = dest_map[index] \| other_map[index];
	// If this has more bits set than dest_map[index], then other is not a
	// subset.
	if (word_union != dest_map[index]) return false;
	}
	return true;
	}

	bool BitMap::intersects(const BitMap other) const {
	assert(size() == other.size(), "must have same size");
	uintptr_t* dest_map = map();
	uintptr_t* other_map = other.map();
	idx_t size = size_in_words();
	for (idx_t index = 0; index < size_in_words(); index++) {
	if ((dest_map[index] & other_map[index]) != 0) return true;
	}
	// Otherwise, no intersection.
	return false;
	}

	void BitMap::set_union(BitMap other) {
	assert(size() == other.size(), "must have same size");
	idx_t* dest_map = map();
	idx_t* other_map = other.map();
	idx_t size = size_in_words();
	for (idx_t index = 0; index < size_in_words(); index++) {
	dest_map[index] = dest_map[index] \| other_map[index];
	}
	}


	void BitMap::set_difference(BitMap other) {
	assert(size() == other.size(), "must have same size");
	idx_t* dest_map = map();
	idx_t* other_map = other.map();
	idx_t size = size_in_words();
	for (idx_t index = 0; index < size_in_words(); index++) {
	dest_map[index] = dest_map[index] & ~(other_map[index]);
	}
	}


	void BitMap::set_intersection(BitMap other) {
	assert(size() == other.size(), "must have same size");
	idx_t* dest_map = map();
	idx_t* other_map = other.map();
	idx_t size = size_in_words();
	for (idx_t index = 0; index < size; index++) {
	dest_map[index] = dest_map[index] & other_map[index];
	}
	}


	bool BitMap::set_union_with_result(BitMap other) {
	assert(size() == other.size(), "must have same size");
	bool changed = false;
	idx_t* dest_map = map();
	idx_t* other_map = other.map();
	idx_t size = size_in_words();
	for (idx_t index = 0; index < size; index++) {
	idx_t temp = map(index) \| other_map[index];
	changed = changed \|\| (temp != map(index));
	map()[index] = temp;
	}
	return changed;
	}


	bool BitMap::set_difference_with_result(BitMap other) {
	assert(size() == other.size(), "must have same size");
	bool changed = false;
	idx_t* dest_map = map();
	idx_t* other_map = other.map();
	idx_t size = size_in_words();
	for (idx_t index = 0; index < size; index++) {
	idx_t temp = dest_map[index] & ~(other_map[index]);
	changed = changed \|\| (temp != dest_map[index]);
	dest_map[index] = temp;
	}
	return changed;
	}


	bool BitMap::set_intersection_with_result(BitMap other) {
	assert(size() == other.size(), "must have same size");
	bool changed = false;
	idx_t* dest_map = map();
	idx_t* other_map = other.map();
	idx_t size = size_in_words();
	for (idx_t index = 0; index < size; index++) {
	idx_t orig = dest_map[index];
	idx_t temp = orig & other_map[index];
	changed = changed \|\| (temp != orig);
	dest_map[index] = temp;
	}
	return changed;
	}


	void BitMap::set_from(BitMap other) {
	assert(size() == other.size(), "must have same size");
	idx_t* dest_map = map();
	idx_t* other_map = other.map();
	idx_t size = size_in_words();
	for (idx_t index = 0; index < size; index++) {
	dest_map[index] = other_map[index];
	}
	}


	bool BitMap::is_same(BitMap other) {
	assert(size() == other.size(), "must have same size");
	idx_t* dest_map = map();
	idx_t* other_map = other.map();
	idx_t size = size_in_words();
	for (idx_t index = 0; index < size; index++) {
	if (dest_map[index] != other_map[index]) return false;
	}
	return true;
	}

	bool BitMap::is_full() const {
	uintptr_t* word = map();
	idx_t rest = size();
	for (; rest >= (idx_t) BitsPerWord; rest -= BitsPerWord) {
	if (*word != (uintptr_t) AllBits) return false;
	word++;
	}
	return rest == 0 \|\| (*word \| ~right_n_bits((int)rest)) == (uintptr_t) AllBits;
	}


	bool BitMap::is_empty() const {
	uintptr_t* word = map();
	idx_t rest = size();
	for (; rest >= (idx_t) BitsPerWord; rest -= BitsPerWord) {
	if (*word != (uintptr_t) NoBits) return false;
	word++;
	}
	return rest == 0 \|\| (*word & right_n_bits((int)rest)) == (uintptr_t) NoBits;
	}

	void BitMap::clear_large() {
	clear_large_range_of_words(0, size_in_words());
	}

	// Note that if the closure itself modifies the bitmap
	// then modifications in and to the left of the _bit_ being
	// currently sampled will not be seen. Note also that the
	// interval [leftOffset, rightOffset) is right open.
	void BitMap::iterate(BitMapClosure* blk, idx_t leftOffset, idx_t rightOffset) {
	verify_range(leftOffset, rightOffset);

	idx_t startIndex = word_index(leftOffset);
	idx_t endIndex = MIN2(word_index(rightOffset) + 1, size_in_words());
	for (idx_t index = startIndex, offset = leftOffset;
	offset < rightOffset && index < endIndex;
	offset = (++index) << LogBitsPerWord) {
	idx_t rest = map(index) >> (offset & (BitsPerWord - 1));
	for (; offset < rightOffset && rest != (uintptr_t)NoBits; offset++) {
	if (rest & 1) {
	blk->do_bit(offset);
	// resample at each closure application
	// (see, for instance, CMS bug 4525989)
	rest = map(index) >> (offset & (BitsPerWord -1));
	// XXX debugging: remove
	// The following assertion assumes that closure application
	// doesn't clear bits (may not be true in general, e.g. G1).
	assert(rest & 1,
	"incorrect shift or closure application can clear bits?");
	}
	rest = rest >> 1;
	}
	}
	}

	BitMap::idx_t BitMap::get_next_one_offset(idx_t l_offset,
	idx_t r_offset) const {
	assert(l_offset <= size(), "BitMap index out of bounds");
	assert(r_offset <= size(), "BitMap index out of bounds");
	assert(l_offset <= r_offset, "l_offset > r_offset ?");

	if (l_offset == r_offset) {
	return l_offset;
	}
	idx_t index = word_index(l_offset);
	idx_t r_index = word_index(r_offset-1) + 1;
	idx_t res_offset = l_offset;

	// check bits including and to the _left_ of offset's position
	idx_t pos = bit_in_word(res_offset);
	idx_t res = map(index) >> pos;
	if (res != (uintptr_t)NoBits) {
	// find the position of the 1-bit
	for (; !(res & 1); res_offset++) {
	res = res >> 1;
	}
	assert(res_offset >= l_offset, "just checking");
	return MIN2(res_offset, r_offset);
	}
	// skip over all word length 0-bit runs
	for (index++; index < r_index; index++) {
	res = map(index);
	if (res != (uintptr_t)NoBits) {
	// found a 1, return the offset
	for (res_offset = index << LogBitsPerWord; !(res & 1);
	res_offset++) {
	res = res >> 1;
	}
	assert(res & 1, "tautology; see loop condition");
	assert(res_offset >= l_offset, "just checking");
	return MIN2(res_offset, r_offset);
	}
	}
	return r_offset;
	}

	BitMap::idx_t BitMap::get_next_zero_offset(idx_t l_offset,
	idx_t r_offset) const {
	assert(l_offset <= size(), "BitMap index out of bounds");
	assert(r_offset <= size(), "BitMap index out of bounds");
	assert(l_offset <= r_offset, "l_offset > r_offset ?");

	if (l_offset == r_offset) {
	return l_offset;
	}
	idx_t index = word_index(l_offset);
	idx_t r_index = word_index(r_offset-1) + 1;
	idx_t res_offset = l_offset;

	// check bits including and to the _left_ of offset's position
	idx_t pos = res_offset & (BitsPerWord - 1);
	idx_t res = (map(index) >> pos) \| left_n_bits((int)pos);

	if (res != (uintptr_t)AllBits) {
	// find the position of the 0-bit
	for (; res & 1; res_offset++) {
	res = res >> 1;
	}
	assert(res_offset >= l_offset, "just checking");
	return MIN2(res_offset, r_offset);
	}
	// skip over all word length 1-bit runs
	for (index++; index < r_index; index++) {
	res = map(index);
	if (res != (uintptr_t)AllBits) {
	// found a 0, return the offset
	for (res_offset = index << LogBitsPerWord; res & 1;
	res_offset++) {
	res = res >> 1;
	}
	assert(!(res & 1), "tautology; see loop condition");
	assert(res_offset >= l_offset, "just checking");
	return MIN2(res_offset, r_offset);
	}
	}
	return r_offset;
	}

	#ifndef PRODUCT

	void BitMap::print_on(outputStream* st) const {
	tty->print("Bitmap(%d):", size());
	for (idx_t index = 0; index < size(); index++) {
	tty->print("%c", at(index) ? '1' : '0');
	}
	tty->cr();
	}

	#endif


	BitMap2D::BitMap2D(uintptr_t* map, idx_t size_in_slots, idx_t bits_per_slot)
	: _bits_per_slot(bits_per_slot)
	, _map(map, size_in_slots * bits_per_slot)
	{
	}


	BitMap2D::BitMap2D(idx_t size_in_slots, idx_t bits_per_slot)
	: _bits_per_slot(bits_per_slot)
	, _map(size_in_slots * bits_per_slot)
	{
	}