bitMap.hpp revision 10871:90aeaed2b342
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See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25#ifndef SHARE_VM_UTILITIES_BITMAP_HPP 26#define SHARE_VM_UTILITIES_BITMAP_HPP 27 28#include "memory/allocation.hpp" 29 30// Forward decl; 31class BitMapClosure; 32 33// Operations for bitmaps represented as arrays of unsigned integers. 34// Bit offsets are numbered from 0 to size-1. 35 36class BitMap VALUE_OBJ_CLASS_SPEC { 37 friend class BitMap2D; 38 39 public: 40 typedef size_t idx_t; // Type used for bit and word indices. 41 typedef uintptr_t bm_word_t; // Element type of array that represents 42 // the bitmap. 43 44 // Hints for range sizes. 45 typedef enum { 46 unknown_range, small_range, large_range 47 } RangeSizeHint; 48 49 private: 50 bm_word_t* _map; // First word in bitmap 51 idx_t _size; // Size of bitmap (in bits) 52 53 // Puts the given value at the given offset, using resize() to size 54 // the bitmap appropriately if needed using factor-of-two expansion. 55 void at_put_grow(idx_t index, bool value); 56 57 protected: 58 // Return the position of bit within the word that contains it (e.g., if 59 // bitmap words are 32 bits, return a number 0 <= n <= 31). 60 static idx_t bit_in_word(idx_t bit) { return bit & (BitsPerWord - 1); } 61 62 // Return a mask that will select the specified bit, when applied to the word 63 // containing the bit. 64 static bm_word_t bit_mask(idx_t bit) { return (bm_word_t)1 << bit_in_word(bit); } 65 66 // Return the index of the word containing the specified bit. 67 static idx_t word_index(idx_t bit) { return bit >> LogBitsPerWord; } 68 69 // Return the bit number of the first bit in the specified word. 70 static idx_t bit_index(idx_t word) { return word << LogBitsPerWord; } 71 72 // Return the array of bitmap words, or a specific word from it. 73 bm_word_t* map() const { return _map; } 74 bm_word_t map(idx_t word) const { return _map[word]; } 75 76 // Return a pointer to the word containing the specified bit. 77 bm_word_t* word_addr(idx_t bit) const { return map() + word_index(bit); } 78 79 // Set a word to a specified value or to all ones; clear a word. 80 void set_word (idx_t word, bm_word_t val) { _map[word] = val; } 81 void set_word (idx_t word) { set_word(word, ~(bm_word_t)0); } 82 void clear_word(idx_t word) { _map[word] = 0; } 83 84 // Utilities for ranges of bits. Ranges are half-open [beg, end). 85 86 // Ranges within a single word. 87 bm_word_t inverted_bit_mask_for_range(idx_t beg, idx_t end) const; 88 void set_range_within_word (idx_t beg, idx_t end); 89 void clear_range_within_word (idx_t beg, idx_t end); 90 void par_put_range_within_word (idx_t beg, idx_t end, bool value); 91 92 // Ranges spanning entire words. 93 void set_range_of_words (idx_t beg, idx_t end); 94 void clear_range_of_words (idx_t beg, idx_t end); 95 void set_large_range_of_words (idx_t beg, idx_t end); 96 void clear_large_range_of_words (idx_t beg, idx_t end); 97 98 // The index of the first full word in a range. 99 idx_t word_index_round_up(idx_t bit) const; 100 101 // Verification. 102 void verify_index(idx_t index) const NOT_DEBUG_RETURN; 103 void verify_range(idx_t beg_index, idx_t end_index) const NOT_DEBUG_RETURN; 104 105 // Statistics. 106 static idx_t* _pop_count_table; 107 static void init_pop_count_table(); 108 static idx_t num_set_bits(bm_word_t w); 109 static idx_t num_set_bits_from_table(unsigned char c); 110 111 public: 112 113 // Constructs a bitmap with no map, and size 0. 114 BitMap() : _map(NULL), _size(0) {} 115 116 // Constructs a bitmap with the given map and size. 117 BitMap(bm_word_t* map, idx_t size_in_bits) :_map(map), _size(size_in_bits) {} 118 119 // Constructs an empty bitmap of the given size (that is, this clears the 120 // new bitmap). Allocates the map array in resource area if 121 // "in_resource_area" is true, else in the C heap. 122 BitMap(idx_t size_in_bits, bool in_resource_area = true); 123 124 // Set the map and size. 125 void set_map(bm_word_t* map) { _map = map; } 126 void set_size(idx_t size_in_bits) { _size = size_in_bits; } 127 128 // Allocates necessary data structure, either in the resource area 129 // or in the C heap, as indicated by "in_resource_area." 130 // Preserves state currently in bit map by copying data. 131 // Zeros any newly-addressable bits. 132 // If "in_resource_area" is false, frees the current map. 133 // (Note that this assumes that all calls to "resize" on the same BitMap 134 // use the same value for "in_resource_area".) 135 void resize(idx_t size_in_bits, bool in_resource_area = true); 136 137 // Pretouch the entire range of memory this BitMap covers. 138 void pretouch(); 139 140 // Accessing 141 idx_t size() const { return _size; } 142 idx_t size_in_bytes() const { return size_in_words() * BytesPerWord; } 143 idx_t size_in_words() const { 144 return calc_size_in_words(size()); 145 } 146 147 static idx_t calc_size_in_words(size_t size_in_bits) { 148 return word_index(size_in_bits + BitsPerWord - 1); 149 } 150 151 bool at(idx_t index) const { 152 verify_index(index); 153 return (*word_addr(index) & bit_mask(index)) != 0; 154 } 155 156 // Align bit index up or down to the next bitmap word boundary, or check 157 // alignment. 158 static idx_t word_align_up(idx_t bit) { 159 return align_size_up(bit, BitsPerWord); 160 } 161 static idx_t word_align_down(idx_t bit) { 162 return align_size_down(bit, BitsPerWord); 163 } 164 static bool is_word_aligned(idx_t bit) { 165 return word_align_up(bit) == bit; 166 } 167 168 // Set or clear the specified bit. 169 inline void set_bit(idx_t bit); 170 inline void clear_bit(idx_t bit); 171 172 // Atomically set or clear the specified bit. 173 inline bool par_set_bit(idx_t bit); 174 inline bool par_clear_bit(idx_t bit); 175 176 // Put the given value at the given offset. The parallel version 177 // will CAS the value into the bitmap and is quite a bit slower. 178 // The parallel version also returns a value indicating if the 179 // calling thread was the one that changed the value of the bit. 180 void at_put(idx_t index, bool value); 181 bool par_at_put(idx_t index, bool value); 182 183 // Update a range of bits. Ranges are half-open [beg, end). 184 void set_range (idx_t beg, idx_t end); 185 void clear_range (idx_t beg, idx_t end); 186 void set_large_range (idx_t beg, idx_t end); 187 void clear_large_range (idx_t beg, idx_t end); 188 void at_put_range(idx_t beg, idx_t end, bool value); 189 void par_at_put_range(idx_t beg, idx_t end, bool value); 190 void at_put_large_range(idx_t beg, idx_t end, bool value); 191 void par_at_put_large_range(idx_t beg, idx_t end, bool value); 192 193 // Update a range of bits, using a hint about the size. Currently only 194 // inlines the predominant case of a 1-bit range. Works best when hint is a 195 // compile-time constant. 196 void set_range(idx_t beg, idx_t end, RangeSizeHint hint); 197 void clear_range(idx_t beg, idx_t end, RangeSizeHint hint); 198 void par_set_range(idx_t beg, idx_t end, RangeSizeHint hint); 199 void par_clear_range (idx_t beg, idx_t end, RangeSizeHint hint); 200 201 // Clearing 202 void clear_large(); 203 inline void clear(); 204 205 // Iteration support. Returns "true" if the iteration completed, false 206 // if the iteration terminated early (because the closure "blk" returned 207 // false). 208 bool iterate(BitMapClosure* blk, idx_t leftIndex, idx_t rightIndex); 209 bool iterate(BitMapClosure* blk) { 210 // call the version that takes an interval 211 return iterate(blk, 0, size()); 212 } 213 214 // Looking for 1's and 0's at indices equal to or greater than "l_index", 215 // stopping if none has been found before "r_index", and returning 216 // "r_index" (which must be at most "size") in that case. 217 idx_t get_next_one_offset_inline (idx_t l_index, idx_t r_index) const; 218 idx_t get_next_zero_offset_inline(idx_t l_index, idx_t r_index) const; 219 220 // Like "get_next_one_offset_inline", except requires that "r_index" is 221 // aligned to bitsizeof(bm_word_t). 222 idx_t get_next_one_offset_inline_aligned_right(idx_t l_index, 223 idx_t r_index) const; 224 225 // Non-inline versionsof the above. 226 idx_t get_next_one_offset (idx_t l_index, idx_t r_index) const; 227 idx_t get_next_zero_offset(idx_t l_index, idx_t r_index) const; 228 229 idx_t get_next_one_offset(idx_t offset) const { 230 return get_next_one_offset(offset, size()); 231 } 232 idx_t get_next_zero_offset(idx_t offset) const { 233 return get_next_zero_offset(offset, size()); 234 } 235 236 // Returns the number of bits set in the bitmap. 237 idx_t count_one_bits() const; 238 239 // Set operations. 240 void set_union(BitMap bits); 241 void set_difference(BitMap bits); 242 void set_intersection(BitMap bits); 243 // Returns true iff "this" is a superset of "bits". 244 bool contains(const BitMap bits) const; 245 // Returns true iff "this and "bits" have a non-empty intersection. 246 bool intersects(const BitMap bits) const; 247 248 // Returns result of whether this map changed 249 // during the operation 250 bool set_union_with_result(BitMap bits); 251 bool set_difference_with_result(BitMap bits); 252 bool set_intersection_with_result(BitMap bits); 253 254 // Requires the submap of "bits" starting at offset to be at least as 255 // large as "this". Modifies "this" to be the intersection of its 256 // current contents and the submap of "bits" starting at "offset" of the 257 // same length as "this." 258 // (For expedience, currently requires the offset to be aligned to the 259 // bitsize of a uintptr_t. This should go away in the future though it 260 // will probably remain a good case to optimize.) 261 void set_intersection_at_offset(BitMap bits, idx_t offset); 262 263 void set_from(BitMap bits); 264 265 bool is_same(BitMap bits); 266 267 // Test if all bits are set or cleared 268 bool is_full() const; 269 bool is_empty() const; 270 271 void print_on_error(outputStream* st, const char* prefix) const; 272 273#ifndef PRODUCT 274 public: 275 // Printing 276 void print_on(outputStream* st) const; 277#endif 278}; 279 280// Convenience class wrapping BitMap which provides multiple bits per slot. 281class BitMap2D VALUE_OBJ_CLASS_SPEC { 282 public: 283 typedef BitMap::idx_t idx_t; // Type used for bit and word indices. 284 typedef BitMap::bm_word_t bm_word_t; // Element type of array that 285 // represents the bitmap. 286 private: 287 BitMap _map; 288 idx_t _bits_per_slot; 289 290 idx_t bit_index(idx_t slot_index, idx_t bit_within_slot_index) const { 291 return slot_index * _bits_per_slot + bit_within_slot_index; 292 } 293 294 void verify_bit_within_slot_index(idx_t index) const { 295 assert(index < _bits_per_slot, "bit_within_slot index out of bounds"); 296 } 297 298 public: 299 // Construction. bits_per_slot must be greater than 0. 300 BitMap2D(bm_word_t* map, idx_t size_in_slots, idx_t bits_per_slot); 301 302 // Allocates necessary data structure in resource area. bits_per_slot must be greater than 0. 303 BitMap2D(idx_t size_in_slots, idx_t bits_per_slot); 304 305 idx_t size_in_bits() { 306 return _map.size(); 307 } 308 309 // Returns number of full slots that have been allocated 310 idx_t size_in_slots() { 311 // Round down 312 return _map.size() / _bits_per_slot; 313 } 314 315 bool is_valid_index(idx_t slot_index, idx_t bit_within_slot_index); 316 bool at(idx_t slot_index, idx_t bit_within_slot_index) const; 317 void set_bit(idx_t slot_index, idx_t bit_within_slot_index); 318 void clear_bit(idx_t slot_index, idx_t bit_within_slot_index); 319 void at_put(idx_t slot_index, idx_t bit_within_slot_index, bool value); 320 void at_put_grow(idx_t slot_index, idx_t bit_within_slot_index, bool value); 321 void clear(); 322}; 323 324// Closure for iterating over BitMaps 325 326class BitMapClosure VALUE_OBJ_CLASS_SPEC { 327 public: 328 // Callback when bit in map is set. Should normally return "true"; 329 // return of false indicates that the bitmap iteration should terminate. 330 virtual bool do_bit(BitMap::idx_t offset) = 0; 331}; 332 333#endif // SHARE_VM_UTILITIES_BITMAP_HPP 334