annotate src/share/vm/utilities/bitMap.hpp @ 1472:c18cbe5936b8

6941466: Oracle rebranding changes for Hotspot repositories Summary: Change all the Sun copyrights to Oracle copyright Reviewed-by: ohair
author trims
date Thu, 27 May 2010 19:08:38 -0700
parents bd02caa94611
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duke@0 1 /*
trims@1472 2 * Copyright (c) 1997, 2009, Oracle and/or its affiliates. All rights reserved.
duke@0 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@0 4 *
duke@0 5 * This code is free software; you can redistribute it and/or modify it
duke@0 6 * under the terms of the GNU General Public License version 2 only, as
duke@0 7 * published by the Free Software Foundation.
duke@0 8 *
duke@0 9 * This code is distributed in the hope that it will be useful, but WITHOUT
duke@0 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@0 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@0 12 * version 2 for more details (a copy is included in the LICENSE file that
duke@0 13 * accompanied this code).
duke@0 14 *
duke@0 15 * You should have received a copy of the GNU General Public License version
duke@0 16 * 2 along with this work; if not, write to the Free Software Foundation,
duke@0 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@0 18 *
trims@1472 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1472 20 * or visit www.oracle.com if you need additional information or have any
trims@1472 21 * questions.
duke@0 22 *
duke@0 23 */
duke@0 24
ysr@342 25 // Forward decl;
ysr@342 26 class BitMapClosure;
duke@0 27
ysr@342 28 // Operations for bitmaps represented as arrays of unsigned integers.
ysr@342 29 // Bit offsets are numbered from 0 to size-1.
duke@0 30
duke@0 31 class BitMap VALUE_OBJ_CLASS_SPEC {
duke@0 32 friend class BitMap2D;
duke@0 33
duke@0 34 public:
duke@0 35 typedef size_t idx_t; // Type used for bit and word indices.
ysr@342 36 typedef uintptr_t bm_word_t; // Element type of array that represents
ysr@342 37 // the bitmap.
duke@0 38
duke@0 39 // Hints for range sizes.
duke@0 40 typedef enum {
duke@0 41 unknown_range, small_range, large_range
duke@0 42 } RangeSizeHint;
duke@0 43
duke@0 44 private:
ysr@342 45 bm_word_t* _map; // First word in bitmap
ysr@342 46 idx_t _size; // Size of bitmap (in bits)
duke@0 47
duke@0 48 // Puts the given value at the given offset, using resize() to size
duke@0 49 // the bitmap appropriately if needed using factor-of-two expansion.
duke@0 50 void at_put_grow(idx_t index, bool value);
duke@0 51
duke@0 52 protected:
duke@0 53 // Return the position of bit within the word that contains it (e.g., if
duke@0 54 // bitmap words are 32 bits, return a number 0 <= n <= 31).
duke@0 55 static idx_t bit_in_word(idx_t bit) { return bit & (BitsPerWord - 1); }
duke@0 56
duke@0 57 // Return a mask that will select the specified bit, when applied to the word
duke@0 58 // containing the bit.
ysr@342 59 static bm_word_t bit_mask(idx_t bit) { return (bm_word_t)1 << bit_in_word(bit); }
duke@0 60
duke@0 61 // Return the index of the word containing the specified bit.
duke@0 62 static idx_t word_index(idx_t bit) { return bit >> LogBitsPerWord; }
duke@0 63
duke@0 64 // Return the bit number of the first bit in the specified word.
duke@0 65 static idx_t bit_index(idx_t word) { return word << LogBitsPerWord; }
duke@0 66
duke@0 67 // Return the array of bitmap words, or a specific word from it.
ysr@342 68 bm_word_t* map() const { return _map; }
ysr@342 69 bm_word_t map(idx_t word) const { return _map[word]; }
duke@0 70
duke@0 71 // Return a pointer to the word containing the specified bit.
ysr@342 72 bm_word_t* word_addr(idx_t bit) const { return map() + word_index(bit); }
duke@0 73
duke@0 74 // Set a word to a specified value or to all ones; clear a word.
ysr@342 75 void set_word (idx_t word, bm_word_t val) { _map[word] = val; }
duke@0 76 void set_word (idx_t word) { set_word(word, ~(uintptr_t)0); }
duke@0 77 void clear_word(idx_t word) { _map[word] = 0; }
duke@0 78
duke@0 79 // Utilities for ranges of bits. Ranges are half-open [beg, end).
duke@0 80
duke@0 81 // Ranges within a single word.
ysr@342 82 bm_word_t inverted_bit_mask_for_range(idx_t beg, idx_t end) const;
ysr@342 83 void set_range_within_word (idx_t beg, idx_t end);
ysr@342 84 void clear_range_within_word (idx_t beg, idx_t end);
ysr@342 85 void par_put_range_within_word (idx_t beg, idx_t end, bool value);
duke@0 86
duke@0 87 // Ranges spanning entire words.
ysr@342 88 void set_range_of_words (idx_t beg, idx_t end);
ysr@342 89 void clear_range_of_words (idx_t beg, idx_t end);
ysr@342 90 void set_large_range_of_words (idx_t beg, idx_t end);
ysr@342 91 void clear_large_range_of_words (idx_t beg, idx_t end);
duke@0 92
duke@0 93 // The index of the first full word in a range.
ysr@342 94 idx_t word_index_round_up(idx_t bit) const;
duke@0 95
jcoomes@809 96 // Verification.
jcoomes@809 97 inline void verify_index(idx_t index) const NOT_DEBUG_RETURN;
jcoomes@809 98 inline void verify_range(idx_t beg_index, idx_t end_index) const
jcoomes@809 99 NOT_DEBUG_RETURN;
duke@0 100
jcoomes@809 101 // Statistics.
ysr@342 102 static idx_t* _pop_count_table;
ysr@342 103 static void init_pop_count_table();
ysr@342 104 static idx_t num_set_bits(bm_word_t w);
ysr@342 105 static idx_t num_set_bits_from_table(unsigned char c);
duke@0 106
duke@0 107 public:
duke@0 108
duke@0 109 // Constructs a bitmap with no map, and size 0.
duke@0 110 BitMap() : _map(NULL), _size(0) {}
duke@0 111
ysr@342 112 // Constructs a bitmap with the given map and size.
ysr@342 113 BitMap(bm_word_t* map, idx_t size_in_bits);
duke@0 114
ysr@342 115 // Constructs an empty bitmap of the given size (that is, this clears the
ysr@342 116 // new bitmap). Allocates the map array in resource area if
ysr@342 117 // "in_resource_area" is true, else in the C heap.
ysr@342 118 BitMap(idx_t size_in_bits, bool in_resource_area = true);
duke@0 119
ysr@342 120 // Set the map and size.
ysr@342 121 void set_map(bm_word_t* map) { _map = map; }
duke@0 122 void set_size(idx_t size_in_bits) { _size = size_in_bits; }
duke@0 123
ysr@342 124 // Allocates necessary data structure, either in the resource area
ysr@342 125 // or in the C heap, as indicated by "in_resource_area."
duke@0 126 // Preserves state currently in bit map by copying data.
duke@0 127 // Zeros any newly-addressable bits.
ysr@342 128 // If "in_resource_area" is false, frees the current map.
ysr@342 129 // (Note that this assumes that all calls to "resize" on the same BitMap
ysr@342 130 // use the same value for "in_resource_area".)
ysr@342 131 void resize(idx_t size_in_bits, bool in_resource_area = true);
duke@0 132
duke@0 133 // Accessing
duke@0 134 idx_t size() const { return _size; }
duke@0 135 idx_t size_in_words() const {
duke@0 136 return word_index(size() + BitsPerWord - 1);
duke@0 137 }
duke@0 138
duke@0 139 bool at(idx_t index) const {
duke@0 140 verify_index(index);
duke@0 141 return (*word_addr(index) & bit_mask(index)) != 0;
duke@0 142 }
duke@0 143
duke@0 144 // Align bit index up or down to the next bitmap word boundary, or check
duke@0 145 // alignment.
duke@0 146 static idx_t word_align_up(idx_t bit) {
duke@0 147 return align_size_up(bit, BitsPerWord);
duke@0 148 }
duke@0 149 static idx_t word_align_down(idx_t bit) {
duke@0 150 return align_size_down(bit, BitsPerWord);
duke@0 151 }
duke@0 152 static bool is_word_aligned(idx_t bit) {
duke@0 153 return word_align_up(bit) == bit;
duke@0 154 }
duke@0 155
duke@0 156 // Set or clear the specified bit.
duke@0 157 inline void set_bit(idx_t bit);
ysr@342 158 void clear_bit(idx_t bit);
duke@0 159
duke@0 160 // Atomically set or clear the specified bit.
ysr@342 161 bool par_set_bit(idx_t bit);
ysr@342 162 bool par_clear_bit(idx_t bit);
duke@0 163
duke@0 164 // Put the given value at the given offset. The parallel version
duke@0 165 // will CAS the value into the bitmap and is quite a bit slower.
duke@0 166 // The parallel version also returns a value indicating if the
duke@0 167 // calling thread was the one that changed the value of the bit.
duke@0 168 void at_put(idx_t index, bool value);
duke@0 169 bool par_at_put(idx_t index, bool value);
duke@0 170
duke@0 171 // Update a range of bits. Ranges are half-open [beg, end).
duke@0 172 void set_range (idx_t beg, idx_t end);
duke@0 173 void clear_range (idx_t beg, idx_t end);
duke@0 174 void set_large_range (idx_t beg, idx_t end);
duke@0 175 void clear_large_range (idx_t beg, idx_t end);
duke@0 176 void at_put_range(idx_t beg, idx_t end, bool value);
duke@0 177 void par_at_put_range(idx_t beg, idx_t end, bool value);
duke@0 178 void at_put_large_range(idx_t beg, idx_t end, bool value);
duke@0 179 void par_at_put_large_range(idx_t beg, idx_t end, bool value);
duke@0 180
duke@0 181 // Update a range of bits, using a hint about the size. Currently only
duke@0 182 // inlines the predominant case of a 1-bit range. Works best when hint is a
duke@0 183 // compile-time constant.
ysr@342 184 void set_range(idx_t beg, idx_t end, RangeSizeHint hint);
ysr@342 185 void clear_range(idx_t beg, idx_t end, RangeSizeHint hint);
ysr@342 186 void par_set_range(idx_t beg, idx_t end, RangeSizeHint hint);
ysr@342 187 void par_clear_range (idx_t beg, idx_t end, RangeSizeHint hint);
ysr@342 188
ysr@342 189 // It performs the union operation between subsets of equal length
ysr@342 190 // of two bitmaps (the target bitmap of the method and the
ysr@342 191 // from_bitmap) and stores the result to the target bitmap. The
ysr@342 192 // from_start_index represents the first bit index of the subrange
ysr@342 193 // of the from_bitmap. The to_start_index is the equivalent of the
ysr@342 194 // target bitmap. Both indexes should be word-aligned, i.e. they
ysr@342 195 // should correspond to the first bit on a bitmap word (it's up to
ysr@342 196 // the caller to ensure this; the method does check it). The length
ysr@342 197 // of the subset is specified with word_num and it is in number of
ysr@342 198 // bitmap words. The caller should ensure that this is at least 2
ysr@342 199 // (smaller ranges are not support to save extra checks). Again,
ysr@342 200 // this is checked in the method.
ysr@342 201 //
ysr@342 202 // Atomicity concerns: it is assumed that any contention on the
ysr@342 203 // target bitmap with other threads will happen on the first and
ysr@342 204 // last words; the ones in between will be "owned" exclusively by
ysr@342 205 // the calling thread and, in fact, they will already be 0. So, the
ysr@342 206 // method performs a CAS on the first word, copies the next
ysr@342 207 // word_num-2 words, and finally performs a CAS on the last word.
ysr@342 208 void mostly_disjoint_range_union(BitMap* from_bitmap,
ysr@342 209 idx_t from_start_index,
ysr@342 210 idx_t to_start_index,
ysr@342 211 size_t word_num);
ysr@342 212
duke@0 213
duke@0 214 // Clearing
duke@0 215 void clear_large();
ysr@342 216 inline void clear();
duke@0 217
ysr@342 218 // Iteration support. Returns "true" if the iteration completed, false
ysr@342 219 // if the iteration terminated early (because the closure "blk" returned
ysr@342 220 // false).
ysr@342 221 bool iterate(BitMapClosure* blk, idx_t leftIndex, idx_t rightIndex);
ysr@342 222 bool iterate(BitMapClosure* blk) {
duke@0 223 // call the version that takes an interval
ysr@342 224 return iterate(blk, 0, size());
duke@0 225 }
duke@0 226
ysr@342 227 // Looking for 1's and 0's at indices equal to or greater than "l_index",
ysr@342 228 // stopping if none has been found before "r_index", and returning
ysr@342 229 // "r_index" (which must be at most "size") in that case.
ysr@342 230 idx_t get_next_one_offset_inline (idx_t l_index, idx_t r_index) const;
ysr@342 231 idx_t get_next_zero_offset_inline(idx_t l_index, idx_t r_index) const;
ysr@342 232
ysr@342 233 // Like "get_next_one_offset_inline", except requires that "r_index" is
ysr@342 234 // aligned to bitsizeof(bm_word_t).
ysr@342 235 idx_t get_next_one_offset_inline_aligned_right(idx_t l_index,
ysr@342 236 idx_t r_index) const;
ysr@342 237
ysr@342 238 // Non-inline versionsof the above.
duke@0 239 idx_t get_next_one_offset (idx_t l_index, idx_t r_index) const;
duke@0 240 idx_t get_next_zero_offset(idx_t l_index, idx_t r_index) const;
duke@0 241
duke@0 242 idx_t get_next_one_offset(idx_t offset) const {
duke@0 243 return get_next_one_offset(offset, size());
duke@0 244 }
duke@0 245 idx_t get_next_zero_offset(idx_t offset) const {
duke@0 246 return get_next_zero_offset(offset, size());
duke@0 247 }
duke@0 248
ysr@342 249 // Returns the number of bits set in the bitmap.
ysr@342 250 idx_t count_one_bits() const;
duke@0 251
duke@0 252 // Set operations.
duke@0 253 void set_union(BitMap bits);
duke@0 254 void set_difference(BitMap bits);
duke@0 255 void set_intersection(BitMap bits);
duke@0 256 // Returns true iff "this" is a superset of "bits".
duke@0 257 bool contains(const BitMap bits) const;
duke@0 258 // Returns true iff "this and "bits" have a non-empty intersection.
duke@0 259 bool intersects(const BitMap bits) const;
duke@0 260
duke@0 261 // Returns result of whether this map changed
duke@0 262 // during the operation
duke@0 263 bool set_union_with_result(BitMap bits);
duke@0 264 bool set_difference_with_result(BitMap bits);
duke@0 265 bool set_intersection_with_result(BitMap bits);
duke@0 266
ysr@342 267 // Requires the submap of "bits" starting at offset to be at least as
ysr@342 268 // large as "this". Modifies "this" to be the intersection of its
ysr@342 269 // current contents and the submap of "bits" starting at "offset" of the
ysr@342 270 // same length as "this."
ysr@342 271 // (For expedience, currently requires the offset to be aligned to the
ysr@342 272 // bitsize of a uintptr_t. This should go away in the future though it
ysr@342 273 // will probably remain a good case to optimize.)
ysr@342 274 void set_intersection_at_offset(BitMap bits, idx_t offset);
ysr@342 275
duke@0 276 void set_from(BitMap bits);
duke@0 277
duke@0 278 bool is_same(BitMap bits);
duke@0 279
duke@0 280 // Test if all bits are set or cleared
duke@0 281 bool is_full() const;
duke@0 282 bool is_empty() const;
duke@0 283
duke@0 284
duke@0 285 #ifndef PRODUCT
duke@0 286 public:
duke@0 287 // Printing
duke@0 288 void print_on(outputStream* st) const;
duke@0 289 #endif
duke@0 290 };
duke@0 291
duke@0 292 // Convenience class wrapping BitMap which provides multiple bits per slot.
duke@0 293 class BitMap2D VALUE_OBJ_CLASS_SPEC {
duke@0 294 public:
ysr@342 295 typedef BitMap::idx_t idx_t; // Type used for bit and word indices.
ysr@342 296 typedef BitMap::bm_word_t bm_word_t; // Element type of array that
ysr@342 297 // represents the bitmap.
duke@0 298 private:
duke@0 299 BitMap _map;
duke@0 300 idx_t _bits_per_slot;
duke@0 301
duke@0 302 idx_t bit_index(idx_t slot_index, idx_t bit_within_slot_index) const {
duke@0 303 return slot_index * _bits_per_slot + bit_within_slot_index;
duke@0 304 }
duke@0 305
duke@0 306 void verify_bit_within_slot_index(idx_t index) const {
duke@0 307 assert(index < _bits_per_slot, "bit_within_slot index out of bounds");
duke@0 308 }
duke@0 309
duke@0 310 public:
duke@0 311 // Construction. bits_per_slot must be greater than 0.
ysr@342 312 BitMap2D(bm_word_t* map, idx_t size_in_slots, idx_t bits_per_slot);
duke@0 313
duke@0 314 // Allocates necessary data structure in resource area. bits_per_slot must be greater than 0.
duke@0 315 BitMap2D(idx_t size_in_slots, idx_t bits_per_slot);
duke@0 316
duke@0 317 idx_t size_in_bits() {
duke@0 318 return _map.size();
duke@0 319 }
duke@0 320
duke@0 321 // Returns number of full slots that have been allocated
duke@0 322 idx_t size_in_slots() {
duke@0 323 // Round down
duke@0 324 return _map.size() / _bits_per_slot;
duke@0 325 }
duke@0 326
duke@0 327 bool is_valid_index(idx_t slot_index, idx_t bit_within_slot_index) {
duke@0 328 verify_bit_within_slot_index(bit_within_slot_index);
duke@0 329 return (bit_index(slot_index, bit_within_slot_index) < size_in_bits());
duke@0 330 }
duke@0 331
duke@0 332 bool at(idx_t slot_index, idx_t bit_within_slot_index) const {
duke@0 333 verify_bit_within_slot_index(bit_within_slot_index);
duke@0 334 return _map.at(bit_index(slot_index, bit_within_slot_index));
duke@0 335 }
duke@0 336
duke@0 337 void set_bit(idx_t slot_index, idx_t bit_within_slot_index) {
duke@0 338 verify_bit_within_slot_index(bit_within_slot_index);
duke@0 339 _map.set_bit(bit_index(slot_index, bit_within_slot_index));
duke@0 340 }
duke@0 341
duke@0 342 void clear_bit(idx_t slot_index, idx_t bit_within_slot_index) {
duke@0 343 verify_bit_within_slot_index(bit_within_slot_index);
duke@0 344 _map.clear_bit(bit_index(slot_index, bit_within_slot_index));
duke@0 345 }
duke@0 346
duke@0 347 void at_put(idx_t slot_index, idx_t bit_within_slot_index, bool value) {
duke@0 348 verify_bit_within_slot_index(bit_within_slot_index);
duke@0 349 _map.at_put(bit_index(slot_index, bit_within_slot_index), value);
duke@0 350 }
duke@0 351
duke@0 352 void at_put_grow(idx_t slot_index, idx_t bit_within_slot_index, bool value) {
duke@0 353 verify_bit_within_slot_index(bit_within_slot_index);
duke@0 354 _map.at_put_grow(bit_index(slot_index, bit_within_slot_index), value);
duke@0 355 }
duke@0 356
ysr@342 357 void clear();
duke@0 358 };
duke@0 359
ysr@342 360 // Closure for iterating over BitMaps
duke@0 361
ysr@342 362 class BitMapClosure VALUE_OBJ_CLASS_SPEC {
ysr@342 363 public:
ysr@342 364 // Callback when bit in map is set. Should normally return "true";
ysr@342 365 // return of false indicates that the bitmap iteration should terminate.
ysr@342 366 virtual bool do_bit(BitMap::idx_t offset) = 0;
ysr@342 367 };