diff -r 4ebc2e2fb97c -r 71c04702a3d5 src/hotspot/share/utilities/bitMap.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/utilities/bitMap.cpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,683 @@
+/*
+ * Copyright (c) 1997, 2017, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "memory/allocation.inline.hpp"
+#include "memory/resourceArea.hpp"
+#include "runtime/atomic.hpp"
+#include "utilities/bitMap.inline.hpp"
+#include "utilities/copy.hpp"
+#include "utilities/debug.hpp"
+
+STATIC_ASSERT(sizeof(BitMap::bm_word_t) == BytesPerWord); // "Implementation assumption."
+
+typedef BitMap::bm_word_t bm_word_t;
+typedef BitMap::idx_t     idx_t;
+
+class ResourceBitMapAllocator : StackObj {
+ public:
+  bm_word_t* allocate(idx_t size_in_words) const {
+    return NEW_RESOURCE_ARRAY(bm_word_t, size_in_words);
+  }
+  void free(bm_word_t* map, idx_t size_in_words) const {
+    // Don't free resource allocated arrays.
+  }
+};
+
+class CHeapBitMapAllocator : StackObj {
+  MEMFLAGS _flags;
+
+ public:
+  CHeapBitMapAllocator(MEMFLAGS flags) : _flags(flags) {}
+  bm_word_t* allocate(size_t size_in_words) const {
+    return ArrayAllocator<bm_word_t>::allocate(size_in_words, _flags);
+  }
+  void free(bm_word_t* map, idx_t size_in_words) const {
+    ArrayAllocator<bm_word_t>::free(map, size_in_words);
+  }
+};
+
+class ArenaBitMapAllocator : StackObj {
+  Arena* _arena;
+
+ public:
+  ArenaBitMapAllocator(Arena* arena) : _arena(arena) {}
+  bm_word_t* allocate(idx_t size_in_words) const {
+    return (bm_word_t*)_arena->Amalloc(size_in_words * BytesPerWord);
+  }
+  void free(bm_word_t* map, idx_t size_in_words) const {
+    // ArenaBitMaps currently don't free memory.
+  }
+};
+
+template <class Allocator>
+BitMap::bm_word_t* BitMap::reallocate(const Allocator& allocator, bm_word_t* old_map, idx_t old_size_in_bits, idx_t new_size_in_bits) {
+  size_t old_size_in_words = calc_size_in_words(old_size_in_bits);
+  size_t new_size_in_words = calc_size_in_words(new_size_in_bits);
+
+  bm_word_t* map = NULL;
+
+  if (new_size_in_words > 0) {
+    map = allocator.allocate(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(map, old_size_in_words, new_size_in_words);
+    }
+  }
+
+  if (old_map != NULL) {
+    allocator.free(old_map, old_size_in_words);
+  }
+
+  return map;
+}
+
+template <class Allocator>
+bm_word_t* BitMap::allocate(const Allocator& allocator, idx_t size_in_bits) {
+  // Reuse reallocate to ensure that the new memory is cleared.
+  return reallocate(allocator, NULL, 0, size_in_bits);
+}
+
+template <class Allocator>
+void BitMap::free(const Allocator& allocator, bm_word_t* map, idx_t  size_in_bits) {
+  bm_word_t* ret = reallocate(allocator, map, size_in_bits, 0);
+  assert(ret == NULL, "Reallocate shouldn't have allocated");
+}
+
+template <class Allocator>
+void BitMap::resize(const Allocator& allocator, idx_t new_size_in_bits) {
+  bm_word_t* new_map = reallocate(allocator, map(), size(), new_size_in_bits);
+
+  update(new_map, new_size_in_bits);
+}
+
+template <class Allocator>
+void BitMap::initialize(const Allocator& allocator, idx_t size_in_bits) {
+  assert(map() == NULL, "precondition");
+  assert(size() == 0,   "precondition");
+
+  resize(allocator, size_in_bits);
+}
+
+template <class Allocator>
+void BitMap::reinitialize(const Allocator& allocator, idx_t new_size_in_bits) {
+  // Remove previous bits.
+  resize(allocator, 0);
+
+  initialize(allocator, new_size_in_bits);
+}
+
+ResourceBitMap::ResourceBitMap(idx_t size_in_bits)
+    : BitMap(allocate(ResourceBitMapAllocator(), size_in_bits), size_in_bits) {
+}
+
+void ResourceBitMap::resize(idx_t new_size_in_bits) {
+  BitMap::resize(ResourceBitMapAllocator(), new_size_in_bits);
+}
+
+void ResourceBitMap::initialize(idx_t size_in_bits) {
+  BitMap::initialize(ResourceBitMapAllocator(), size_in_bits);
+}
+
+void ResourceBitMap::reinitialize(idx_t size_in_bits) {
+  BitMap::reinitialize(ResourceBitMapAllocator(), size_in_bits);
+}
+
+ArenaBitMap::ArenaBitMap(Arena* arena, idx_t size_in_bits)
+    : BitMap(allocate(ArenaBitMapAllocator(arena), size_in_bits), size_in_bits) {
+}
+
+CHeapBitMap::CHeapBitMap(idx_t size_in_bits, MEMFLAGS flags)
+    : BitMap(allocate(CHeapBitMapAllocator(flags), size_in_bits), size_in_bits), _flags(flags) {
+}
+
+CHeapBitMap::~CHeapBitMap() {
+  free(CHeapBitMapAllocator(_flags), map(), size());
+}
+
+void CHeapBitMap::resize(idx_t new_size_in_bits) {
+  BitMap::resize(CHeapBitMapAllocator(_flags), new_size_in_bits);
+}
+
+void CHeapBitMap::initialize(idx_t size_in_bits) {
+  BitMap::initialize(CHeapBitMapAllocator(_flags), size_in_bits);
+}
+
+void CHeapBitMap::reinitialize(idx_t size_in_bits) {
+  BitMap::reinitialize(CHeapBitMapAllocator(_flags), size_in_bits);
+}
+
+#ifdef ASSERT
+void BitMap::verify_index(idx_t index) const {
+  assert(index < _size, "BitMap index out of bounds");
+}
+
+void BitMap::verify_range(idx_t beg_index, idx_t end_index) const {
+  assert(beg_index <= end_index, "BitMap range error");
+  // Note that [0,0) and [size,size) are both valid ranges.
+  if (end_index != _size) verify_index(end_index);
+}
+#endif // #ifdef ASSERT
+
+void BitMap::pretouch() {
+  os::pretouch_memory(word_addr(0), word_addr(size()));
+}
+
+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) {
+    bm_word_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) {
+    bm_word_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) {
+    bm_word_t* pw = word_addr(beg);
+    bm_word_t  w  = *pw;
+    bm_word_t  mr = inverted_bit_mask_for_range(beg, end);
+    bm_word_t  nw = value ? (w | ~mr) : (w & mr);
+    while (true) {
+      bm_word_t res = Atomic::cmpxchg(nw, pw, w);
+      if (res == w) break;
+      w  = res;
+      nw = value ? (w | ~mr) : (w & mr);
+    }
+  }
+}
+
+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);
+
+  if (end_full_word - beg_full_word < 32) {
+    clear_range(beg, end);
+    return;
+  }
+
+  // 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_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);
+}
+
+inline bm_word_t tail_mask(idx_t tail_bits) {
+  assert(tail_bits != 0, "precondition"); // Works, but shouldn't be called.
+  assert(tail_bits < (idx_t)BitsPerWord, "precondition");
+  return (bm_word_t(1) << tail_bits) - 1;
+}
+
+// Get the low tail_bits of value, which is the last partial word of a map.
+inline bm_word_t tail_of_map(bm_word_t value, idx_t tail_bits) {
+  return value & tail_mask(tail_bits);
+}
+
+// Compute the new last word of a map with a non-aligned length.
+// new_value has the new trailing bits of the map in the low tail_bits.
+// old_value is the last word of the map, including bits beyond the end.
+// Returns old_value with the low tail_bits replaced by the corresponding
+// bits in new_value.
+inline bm_word_t merge_tail_of_map(bm_word_t new_value,
+                                   bm_word_t old_value,
+                                   idx_t tail_bits) {
+  bm_word_t mask = tail_mask(tail_bits);
+  return (new_value & mask) | (old_value & ~mask);
+}
+
+bool BitMap::contains(const BitMap& other) const {
+  assert(size() == other.size(), "must have same size");
+  const bm_word_t* dest_map = map();
+  const bm_word_t* other_map = other.map();
+  idx_t limit = word_index(size());
+  for (idx_t index = 0; index < limit; ++index) {
+    // false if other bitmap has bits set which are clear in this bitmap.
+    if ((~dest_map[index] & other_map[index]) != 0) return false;
+  }
+  idx_t rest = bit_in_word(size());
+  // true unless there is a partial-word tail in which the other
+  // bitmap has bits set which are clear in this bitmap.
+  return (rest == 0) || tail_of_map(~dest_map[limit] & other_map[limit], rest) == 0;
+}
+
+bool BitMap::intersects(const BitMap& other) const {
+  assert(size() == other.size(), "must have same size");
+  const bm_word_t* dest_map = map();
+  const bm_word_t* other_map = other.map();
+  idx_t limit = word_index(size());
+  for (idx_t index = 0; index < limit; ++index) {
+    if ((dest_map[index] & other_map[index]) != 0) return true;
+  }
+  idx_t rest = bit_in_word(size());
+  // false unless there is a partial-word tail with non-empty intersection.
+  return (rest > 0) && tail_of_map(dest_map[limit] & other_map[limit], rest) != 0;
+}
+
+void BitMap::set_union(const BitMap& other) {
+  assert(size() == other.size(), "must have same size");
+  bm_word_t* dest_map = map();
+  const bm_word_t* other_map = other.map();
+  idx_t limit = word_index(size());
+  for (idx_t index = 0; index < limit; ++index) {
+    dest_map[index] |= other_map[index];
+  }
+  idx_t rest = bit_in_word(size());
+  if (rest > 0) {
+    bm_word_t orig = dest_map[limit];
+    dest_map[limit] = merge_tail_of_map(orig | other_map[limit], orig, rest);
+  }
+}
+
+void BitMap::set_difference(const BitMap& other) {
+  assert(size() == other.size(), "must have same size");
+  bm_word_t* dest_map = map();
+  const bm_word_t* other_map = other.map();
+  idx_t limit = word_index(size());
+  for (idx_t index = 0; index < limit; ++index) {
+    dest_map[index] &= ~other_map[index];
+  }
+  idx_t rest = bit_in_word(size());
+  if (rest > 0) {
+    bm_word_t orig = dest_map[limit];
+    dest_map[limit] = merge_tail_of_map(orig & ~other_map[limit], orig, rest);
+  }
+}
+
+void BitMap::set_intersection(const BitMap& other) {
+  assert(size() == other.size(), "must have same size");
+  bm_word_t* dest_map = map();
+  const bm_word_t* other_map = other.map();
+  idx_t limit = word_index(size());
+  for (idx_t index = 0; index < limit; ++index) {
+    dest_map[index] &= other_map[index];
+  }
+  idx_t rest = bit_in_word(size());
+  if (rest > 0) {
+    bm_word_t orig = dest_map[limit];
+    dest_map[limit] = merge_tail_of_map(orig & other_map[limit], orig, rest);
+  }
+}
+
+bool BitMap::set_union_with_result(const BitMap& other) {
+  assert(size() == other.size(), "must have same size");
+  bool changed = false;
+  bm_word_t* dest_map = map();
+  const bm_word_t* other_map = other.map();
+  idx_t limit = word_index(size());
+  for (idx_t index = 0; index < limit; ++index) {
+    bm_word_t orig = dest_map[index];
+    bm_word_t temp = orig | other_map[index];
+    changed = changed || (temp != orig);
+    dest_map[index] = temp;
+  }
+  idx_t rest = bit_in_word(size());
+  if (rest > 0) {
+    bm_word_t orig = dest_map[limit];
+    bm_word_t temp = merge_tail_of_map(orig | other_map[limit], orig, rest);
+    changed = changed || (temp != orig);
+    dest_map[limit] = temp;
+  }
+  return changed;
+}
+
+bool BitMap::set_difference_with_result(const BitMap& other) {
+  assert(size() == other.size(), "must have same size");
+  bool changed = false;
+  bm_word_t* dest_map = map();
+  const bm_word_t* other_map = other.map();
+  idx_t limit = word_index(size());
+  for (idx_t index = 0; index < limit; ++index) {
+    bm_word_t orig = dest_map[index];
+    bm_word_t temp = orig & ~other_map[index];
+    changed = changed || (temp != orig);
+    dest_map[index] = temp;
+  }
+  idx_t rest = bit_in_word(size());
+  if (rest > 0) {
+    bm_word_t orig = dest_map[limit];
+    bm_word_t temp = merge_tail_of_map(orig & ~other_map[limit], orig, rest);
+    changed = changed || (temp != orig);
+    dest_map[limit] = temp;
+  }
+  return changed;
+}
+
+bool BitMap::set_intersection_with_result(const BitMap& other) {
+  assert(size() == other.size(), "must have same size");
+  bool changed = false;
+  bm_word_t* dest_map = map();
+  const bm_word_t* other_map = other.map();
+  idx_t limit = word_index(size());
+  for (idx_t index = 0; index < limit; ++index) {
+    bm_word_t orig = dest_map[index];
+    bm_word_t temp = orig & other_map[index];
+    changed = changed || (temp != orig);
+    dest_map[index] = temp;
+  }
+  idx_t rest = bit_in_word(size());
+  if (rest > 0) {
+    bm_word_t orig = dest_map[limit];
+    bm_word_t temp = merge_tail_of_map(orig & other_map[limit], orig, rest);
+    changed = changed || (temp != orig);
+    dest_map[limit] = temp;
+  }
+  return changed;
+}
+
+void BitMap::set_from(const BitMap& other) {
+  assert(size() == other.size(), "must have same size");
+  bm_word_t* dest_map = map();
+  const bm_word_t* other_map = other.map();
+  idx_t copy_words = word_index(size());
+  Copy::disjoint_words((HeapWord*)other_map, (HeapWord*)dest_map, copy_words);
+  idx_t rest = bit_in_word(size());
+  if (rest > 0) {
+    dest_map[copy_words] = merge_tail_of_map(other_map[copy_words],
+                                             dest_map[copy_words],
+                                             rest);
+  }
+}
+
+bool BitMap::is_same(const BitMap& other) const {
+  assert(size() == other.size(), "must have same size");
+  const bm_word_t* dest_map = map();
+  const bm_word_t* other_map = other.map();
+  idx_t limit = word_index(size());
+  for (idx_t index = 0; index < limit; ++index) {
+    if (dest_map[index] != other_map[index]) return false;
+  }
+  idx_t rest = bit_in_word(size());
+  return (rest == 0) || (tail_of_map(dest_map[limit] ^ other_map[limit], rest) == 0);
+}
+
+bool BitMap::is_full() const {
+  const bm_word_t* words = map();
+  idx_t limit = word_index(size());
+  for (idx_t index = 0; index < limit; ++index) {
+    if (~words[index] != 0) return false;
+  }
+  idx_t rest = bit_in_word(size());
+  return (rest == 0) || (tail_of_map(~words[limit], rest) == 0);
+}
+
+bool BitMap::is_empty() const {
+  const bm_word_t* words = map();
+  idx_t limit = word_index(size());
+  for (idx_t index = 0; index < limit; ++index) {
+    if (words[index] != 0) return false;
+  }
+  idx_t rest = bit_in_word(size());
+  return (rest == 0) || (tail_of_map(words[limit], rest) == 0);
+}
+
+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.
+bool 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 != 0; offset++) {
+      if (rest & 1) {
+        if (!blk->do_bit(offset)) return false;
+        //  resample at each closure application
+        // (see, for instance, CMS bug 4525989)
+        rest = map(index) >> (offset & (BitsPerWord -1));
+      }
+      rest = rest >> 1;
+    }
+  }
+  return true;
+}
+
+const BitMap::idx_t* BitMap::_pop_count_table = NULL;
+
+void BitMap::init_pop_count_table() {
+  if (_pop_count_table == NULL) {
+    BitMap::idx_t *table = NEW_C_HEAP_ARRAY(idx_t, 256, mtInternal);
+    for (uint i = 0; i < 256; i++) {
+      table[i] = num_set_bits(i);
+    }
+
+    if (!Atomic::replace_if_null(table, &_pop_count_table)) {
+      guarantee(_pop_count_table != NULL, "invariant");
+      FREE_C_HEAP_ARRAY(idx_t, table);
+    }
+  }
+}
+
+BitMap::idx_t BitMap::num_set_bits(bm_word_t w) {
+  idx_t bits = 0;
+
+  while (w != 0) {
+    while ((w & 1) == 0) {
+      w >>= 1;
+    }
+    bits++;
+    w >>= 1;
+  }
+  return bits;
+}
+
+BitMap::idx_t BitMap::num_set_bits_from_table(unsigned char c) {
+  assert(_pop_count_table != NULL, "precondition");
+  return _pop_count_table[c];
+}
+
+BitMap::idx_t BitMap::count_one_bits() const {
+  init_pop_count_table(); // If necessary.
+  idx_t sum = 0;
+  typedef unsigned char uchar;
+  for (idx_t i = 0; i < size_in_words(); i++) {
+    bm_word_t w = map()[i];
+    for (size_t j = 0; j < sizeof(bm_word_t); j++) {
+      sum += num_set_bits_from_table(uchar(w & 255));
+      w >>= 8;
+    }
+  }
+  return sum;
+}
+
+void BitMap::print_on_error(outputStream* st, const char* prefix) const {
+  st->print_cr("%s[" PTR_FORMAT ", " PTR_FORMAT ")",
+      prefix, p2i(map()), p2i((char*)map() + (size() >> LogBitsPerByte)));
+}
+
+#ifndef PRODUCT
+
+void BitMap::print_on(outputStream* st) const {
+  tty->print("Bitmap(" SIZE_FORMAT "):", size());
+  for (idx_t index = 0; index < size(); index++) {
+    tty->print("%c", at(index) ? '1' : '0');
+  }
+  tty->cr();
+}
+
+#endif