annotate src/share/vm/utilities/bitMap.hpp @ 342:37f87013dfd8

6711316: Open source the Garbage-First garbage collector Summary: First mercurial integration of the code for the Garbage-First garbage collector. Reviewed-by: apetrusenko, iveresov, jmasa, sgoldman, tonyp, ysr
author ysr
date Thu, 05 Jun 2008 15:57:56 -0700
parents a61af66fc99e
children 6e2afda171db
rev   line source
duke@0 1 /*
duke@0 2 * Copyright 1997-2006 Sun Microsystems, Inc. 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 *
duke@0 19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@0 20 * CA 95054 USA or visit www.sun.com if you need additional information or
duke@0 21 * have any 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
duke@0 96 // Verification, statistics.
ysr@342 97 void verify_index(idx_t index) const;
ysr@342 98 void verify_range(idx_t beg_index, idx_t end_index) const;
duke@0 99
ysr@342 100 static idx_t* _pop_count_table;
ysr@342 101 static void init_pop_count_table();
ysr@342 102 static idx_t num_set_bits(bm_word_t w);
ysr@342 103 static idx_t num_set_bits_from_table(unsigned char c);
duke@0 104
duke@0 105 public:
duke@0 106
duke@0 107 // Constructs a bitmap with no map, and size 0.
duke@0 108 BitMap() : _map(NULL), _size(0) {}
duke@0 109
ysr@342 110 // Constructs a bitmap with the given map and size.
ysr@342 111 BitMap(bm_word_t* map, idx_t size_in_bits);
duke@0 112
ysr@342 113 // Constructs an empty bitmap of the given size (that is, this clears the
ysr@342 114 // new bitmap). Allocates the map array in resource area if
ysr@342 115 // "in_resource_area" is true, else in the C heap.
ysr@342 116 BitMap(idx_t size_in_bits, bool in_resource_area = true);
duke@0 117
ysr@342 118 // Set the map and size.
ysr@342 119 void set_map(bm_word_t* map) { _map = map; }
duke@0 120 void set_size(idx_t size_in_bits) { _size = size_in_bits; }
duke@0 121
ysr@342 122 // Allocates necessary data structure, either in the resource area
ysr@342 123 // or in the C heap, as indicated by "in_resource_area."
duke@0 124 // Preserves state currently in bit map by copying data.
duke@0 125 // Zeros any newly-addressable bits.
ysr@342 126 // If "in_resource_area" is false, frees the current map.
ysr@342 127 // (Note that this assumes that all calls to "resize" on the same BitMap
ysr@342 128 // use the same value for "in_resource_area".)
ysr@342 129 void resize(idx_t size_in_bits, bool in_resource_area = true);
duke@0 130
duke@0 131 // Accessing
duke@0 132 idx_t size() const { return _size; }
duke@0 133 idx_t size_in_words() const {
duke@0 134 return word_index(size() + BitsPerWord - 1);
duke@0 135 }
duke@0 136
duke@0 137 bool at(idx_t index) const {
duke@0 138 verify_index(index);
duke@0 139 return (*word_addr(index) & bit_mask(index)) != 0;
duke@0 140 }
duke@0 141
duke@0 142 // Align bit index up or down to the next bitmap word boundary, or check
duke@0 143 // alignment.
duke@0 144 static idx_t word_align_up(idx_t bit) {
duke@0 145 return align_size_up(bit, BitsPerWord);
duke@0 146 }
duke@0 147 static idx_t word_align_down(idx_t bit) {
duke@0 148 return align_size_down(bit, BitsPerWord);
duke@0 149 }
duke@0 150 static bool is_word_aligned(idx_t bit) {
duke@0 151 return word_align_up(bit) == bit;
duke@0 152 }
duke@0 153
duke@0 154 // Set or clear the specified bit.
duke@0 155 inline void set_bit(idx_t bit);
ysr@342 156 void clear_bit(idx_t bit);
duke@0 157
duke@0 158 // Atomically set or clear the specified bit.
ysr@342 159 bool par_set_bit(idx_t bit);
ysr@342 160 bool par_clear_bit(idx_t bit);
duke@0 161
duke@0 162 // Put the given value at the given offset. The parallel version
duke@0 163 // will CAS the value into the bitmap and is quite a bit slower.
duke@0 164 // The parallel version also returns a value indicating if the
duke@0 165 // calling thread was the one that changed the value of the bit.
duke@0 166 void at_put(idx_t index, bool value);
duke@0 167 bool par_at_put(idx_t index, bool value);
duke@0 168
duke@0 169 // Update a range of bits. Ranges are half-open [beg, end).
duke@0 170 void set_range (idx_t beg, idx_t end);
duke@0 171 void clear_range (idx_t beg, idx_t end);
duke@0 172 void set_large_range (idx_t beg, idx_t end);
duke@0 173 void clear_large_range (idx_t beg, idx_t end);
duke@0 174 void at_put_range(idx_t beg, idx_t end, bool value);
duke@0 175 void par_at_put_range(idx_t beg, idx_t end, bool value);
duke@0 176 void at_put_large_range(idx_t beg, idx_t end, bool value);
duke@0 177 void par_at_put_large_range(idx_t beg, idx_t end, bool value);
duke@0 178
duke@0 179 // Update a range of bits, using a hint about the size. Currently only
duke@0 180 // inlines the predominant case of a 1-bit range. Works best when hint is a
duke@0 181 // compile-time constant.
ysr@342 182 void set_range(idx_t beg, idx_t end, RangeSizeHint hint);
ysr@342 183 void clear_range(idx_t beg, idx_t end, RangeSizeHint hint);
ysr@342 184 void par_set_range(idx_t beg, idx_t end, RangeSizeHint hint);
ysr@342 185 void par_clear_range (idx_t beg, idx_t end, RangeSizeHint hint);
ysr@342 186
ysr@342 187 // It performs the union operation between subsets of equal length
ysr@342 188 // of two bitmaps (the target bitmap of the method and the
ysr@342 189 // from_bitmap) and stores the result to the target bitmap. The
ysr@342 190 // from_start_index represents the first bit index of the subrange
ysr@342 191 // of the from_bitmap. The to_start_index is the equivalent of the
ysr@342 192 // target bitmap. Both indexes should be word-aligned, i.e. they
ysr@342 193 // should correspond to the first bit on a bitmap word (it's up to
ysr@342 194 // the caller to ensure this; the method does check it). The length
ysr@342 195 // of the subset is specified with word_num and it is in number of
ysr@342 196 // bitmap words. The caller should ensure that this is at least 2
ysr@342 197 // (smaller ranges are not support to save extra checks). Again,
ysr@342 198 // this is checked in the method.
ysr@342 199 //
ysr@342 200 // Atomicity concerns: it is assumed that any contention on the
ysr@342 201 // target bitmap with other threads will happen on the first and
ysr@342 202 // last words; the ones in between will be "owned" exclusively by
ysr@342 203 // the calling thread and, in fact, they will already be 0. So, the
ysr@342 204 // method performs a CAS on the first word, copies the next
ysr@342 205 // word_num-2 words, and finally performs a CAS on the last word.
ysr@342 206 void mostly_disjoint_range_union(BitMap* from_bitmap,
ysr@342 207 idx_t from_start_index,
ysr@342 208 idx_t to_start_index,
ysr@342 209 size_t word_num);
ysr@342 210
duke@0 211
duke@0 212 // Clearing
duke@0 213 void clear_large();
ysr@342 214 inline void clear();
duke@0 215
ysr@342 216 // Iteration support. Returns "true" if the iteration completed, false
ysr@342 217 // if the iteration terminated early (because the closure "blk" returned
ysr@342 218 // false).
ysr@342 219 bool iterate(BitMapClosure* blk, idx_t leftIndex, idx_t rightIndex);
ysr@342 220 bool iterate(BitMapClosure* blk) {
duke@0 221 // call the version that takes an interval
ysr@342 222 return iterate(blk, 0, size());
duke@0 223 }
duke@0 224
ysr@342 225 // Looking for 1's and 0's at indices equal to or greater than "l_index",
ysr@342 226 // stopping if none has been found before "r_index", and returning
ysr@342 227 // "r_index" (which must be at most "size") in that case.
ysr@342 228 idx_t get_next_one_offset_inline (idx_t l_index, idx_t r_index) const;
ysr@342 229 idx_t get_next_zero_offset_inline(idx_t l_index, idx_t r_index) const;
ysr@342 230
ysr@342 231 // Like "get_next_one_offset_inline", except requires that "r_index" is
ysr@342 232 // aligned to bitsizeof(bm_word_t).
ysr@342 233 idx_t get_next_one_offset_inline_aligned_right(idx_t l_index,
ysr@342 234 idx_t r_index) const;
ysr@342 235
ysr@342 236 // Non-inline versionsof the above.
duke@0 237 idx_t get_next_one_offset (idx_t l_index, idx_t r_index) const;
duke@0 238 idx_t get_next_zero_offset(idx_t l_index, idx_t r_index) const;
duke@0 239
duke@0 240 idx_t get_next_one_offset(idx_t offset) const {
duke@0 241 return get_next_one_offset(offset, size());
duke@0 242 }
duke@0 243 idx_t get_next_zero_offset(idx_t offset) const {
duke@0 244 return get_next_zero_offset(offset, size());
duke@0 245 }
duke@0 246
ysr@342 247 // Returns the number of bits set in the bitmap.
ysr@342 248 idx_t count_one_bits() const;
duke@0 249
duke@0 250 // Set operations.
duke@0 251 void set_union(BitMap bits);
duke@0 252 void set_difference(BitMap bits);
duke@0 253 void set_intersection(BitMap bits);
duke@0 254 // Returns true iff "this" is a superset of "bits".
duke@0 255 bool contains(const BitMap bits) const;
duke@0 256 // Returns true iff "this and "bits" have a non-empty intersection.
duke@0 257 bool intersects(const BitMap bits) const;
duke@0 258
duke@0 259 // Returns result of whether this map changed
duke@0 260 // during the operation
duke@0 261 bool set_union_with_result(BitMap bits);
duke@0 262 bool set_difference_with_result(BitMap bits);
duke@0 263 bool set_intersection_with_result(BitMap bits);
duke@0 264
ysr@342 265 // Requires the submap of "bits" starting at offset to be at least as
ysr@342 266 // large as "this". Modifies "this" to be the intersection of its
ysr@342 267 // current contents and the submap of "bits" starting at "offset" of the
ysr@342 268 // same length as "this."
ysr@342 269 // (For expedience, currently requires the offset to be aligned to the
ysr@342 270 // bitsize of a uintptr_t. This should go away in the future though it
ysr@342 271 // will probably remain a good case to optimize.)
ysr@342 272 void set_intersection_at_offset(BitMap bits, idx_t offset);
ysr@342 273
duke@0 274 void set_from(BitMap bits);
duke@0 275
duke@0 276 bool is_same(BitMap bits);
duke@0 277
duke@0 278 // Test if all bits are set or cleared
duke@0 279 bool is_full() const;
duke@0 280 bool is_empty() const;
duke@0 281
duke@0 282
duke@0 283 #ifndef PRODUCT
duke@0 284 public:
duke@0 285 // Printing
duke@0 286 void print_on(outputStream* st) const;
duke@0 287 #endif
duke@0 288 };
duke@0 289
duke@0 290
duke@0 291 // Convenience class wrapping BitMap which provides multiple bits per slot.
duke@0 292 class BitMap2D VALUE_OBJ_CLASS_SPEC {
duke@0 293 public:
ysr@342 294 typedef BitMap::idx_t idx_t; // Type used for bit and word indices.
ysr@342 295 typedef BitMap::bm_word_t bm_word_t; // Element type of array that
ysr@342 296 // represents the bitmap.
duke@0 297 private:
duke@0 298 BitMap _map;
duke@0 299 idx_t _bits_per_slot;
duke@0 300
duke@0 301 idx_t bit_index(idx_t slot_index, idx_t bit_within_slot_index) const {
duke@0 302 return slot_index * _bits_per_slot + bit_within_slot_index;
duke@0 303 }
duke@0 304
duke@0 305 void verify_bit_within_slot_index(idx_t index) const {
duke@0 306 assert(index < _bits_per_slot, "bit_within_slot index out of bounds");
duke@0 307 }
duke@0 308
duke@0 309 public:
duke@0 310 // Construction. bits_per_slot must be greater than 0.
ysr@342 311 BitMap2D(bm_word_t* map, idx_t size_in_slots, idx_t bits_per_slot);
duke@0 312
duke@0 313 // Allocates necessary data structure in resource area. bits_per_slot must be greater than 0.
duke@0 314 BitMap2D(idx_t size_in_slots, idx_t bits_per_slot);
duke@0 315
duke@0 316 idx_t size_in_bits() {
duke@0 317 return _map.size();
duke@0 318 }
duke@0 319
duke@0 320 // Returns number of full slots that have been allocated
duke@0 321 idx_t size_in_slots() {
duke@0 322 // Round down
duke@0 323 return _map.size() / _bits_per_slot;
duke@0 324 }
duke@0 325
duke@0 326 bool is_valid_index(idx_t slot_index, idx_t bit_within_slot_index) {
duke@0 327 verify_bit_within_slot_index(bit_within_slot_index);
duke@0 328 return (bit_index(slot_index, bit_within_slot_index) < size_in_bits());
duke@0 329 }
duke@0 330
duke@0 331 bool at(idx_t slot_index, idx_t bit_within_slot_index) const {
duke@0 332 verify_bit_within_slot_index(bit_within_slot_index);
duke@0 333 return _map.at(bit_index(slot_index, bit_within_slot_index));
duke@0 334 }
duke@0 335
duke@0 336 void set_bit(idx_t slot_index, idx_t bit_within_slot_index) {
duke@0 337 verify_bit_within_slot_index(bit_within_slot_index);
duke@0 338 _map.set_bit(bit_index(slot_index, bit_within_slot_index));
duke@0 339 }
duke@0 340
duke@0 341 void clear_bit(idx_t slot_index, idx_t bit_within_slot_index) {
duke@0 342 verify_bit_within_slot_index(bit_within_slot_index);
duke@0 343 _map.clear_bit(bit_index(slot_index, bit_within_slot_index));
duke@0 344 }
duke@0 345
duke@0 346 void at_put(idx_t slot_index, idx_t bit_within_slot_index, bool value) {
duke@0 347 verify_bit_within_slot_index(bit_within_slot_index);
duke@0 348 _map.at_put(bit_index(slot_index, bit_within_slot_index), value);
duke@0 349 }
duke@0 350
duke@0 351 void at_put_grow(idx_t slot_index, idx_t bit_within_slot_index, bool value) {
duke@0 352 verify_bit_within_slot_index(bit_within_slot_index);
duke@0 353 _map.at_put_grow(bit_index(slot_index, bit_within_slot_index), value);
duke@0 354 }
duke@0 355
ysr@342 356 void clear();
duke@0 357 };
duke@0 358
ysr@342 359 // Closure for iterating over BitMaps
duke@0 360
ysr@342 361 class BitMapClosure VALUE_OBJ_CLASS_SPEC {
ysr@342 362 public:
ysr@342 363 // Callback when bit in map is set. Should normally return "true";
ysr@342 364 // return of false indicates that the bitmap iteration should terminate.
ysr@342 365 virtual bool do_bit(BitMap::idx_t offset) = 0;
ysr@342 366 };