1 /* 2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. 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 #include "utilities/top.hpp" 30 31 // Forward decl; 32 class BitMapClosure; 33 34 // Operations for bitmaps represented as arrays of unsigned integers. 35 // Bit offsets are numbered from 0 to size-1. 36 37 class BitMap VALUE_OBJ_CLASS_SPEC { 38 friend class BitMap2D; 39 40 public: 41 typedef size_t idx_t; // Type used for bit and word indices. 42 typedef uintptr_t bm_word_t; // Element type of array that represents 43 // the bitmap. 44 45 // Hints for range sizes. 46 typedef enum { 47 unknown_range, small_range, large_range 48 } RangeSizeHint; 49 50 private: 51 ArrayAllocator<bm_word_t, mtInternal> _map_allocator; 52 bm_word_t* _map; // First word in bitmap 53 idx_t _size; // Size of bitmap (in bits) 54 55 // Puts the given value at the given offset, using resize() to size 56 // the bitmap appropriately if needed using factor-of-two expansion. 57 void at_put_grow(idx_t index, bool value); 58 59 protected: 60 // Return the position of bit within the word that contains it (e.g., if 61 // bitmap words are 32 bits, return a number 0 <= n <= 31). 62 static idx_t bit_in_word(idx_t bit) { return bit & (BitsPerWord - 1); } 63 64 // Return a mask that will select the specified bit, when applied to the word 65 // containing the bit. 66 static bm_word_t bit_mask(idx_t bit) { return (bm_word_t)1 << bit_in_word(bit); } 67 68 // Return the index of the word containing the specified bit. 69 static idx_t word_index(idx_t bit) { return bit >> LogBitsPerWord; } 70 71 // Return the bit number of the first bit in the specified word. 72 static idx_t bit_index(idx_t word) { return word << LogBitsPerWord; } 73 74 // Return the array of bitmap words, or a specific word from it. 75 bm_word_t* map() const { return _map; } 76 bm_word_t map(idx_t word) const { return _map[word]; } 77 78 // Return a pointer to the word containing the specified bit. 79 bm_word_t* word_addr(idx_t bit) const { return map() + word_index(bit); } 80 81 // Set a word to a specified value or to all ones; clear a word. 82 void set_word (idx_t word, bm_word_t val) { _map[word] = val; } 83 void set_word (idx_t word) { set_word(word, ~(bm_word_t)0); } 84 void clear_word(idx_t word) { _map[word] = 0; } 85 86 // Utilities for ranges of bits. Ranges are half-open [beg, end). 87 88 // Ranges within a single word. 89 bm_word_t inverted_bit_mask_for_range(idx_t beg, idx_t end) const; 90 void set_range_within_word (idx_t beg, idx_t end); 91 void clear_range_within_word (idx_t beg, idx_t end); 92 void par_put_range_within_word (idx_t beg, idx_t end, bool value); 93 94 // Ranges spanning entire words. 95 void set_range_of_words (idx_t beg, idx_t end); 96 void clear_range_of_words (idx_t beg, idx_t end); 97 void set_large_range_of_words (idx_t beg, idx_t end); 98 void clear_large_range_of_words (idx_t beg, idx_t end); 99 100 // The index of the first full word in a range. 101 idx_t word_index_round_up(idx_t bit) const; 102 103 // Verification. 104 inline void verify_index(idx_t index) const NOT_DEBUG_RETURN; 105 inline void verify_range(idx_t beg_index, idx_t end_index) const 106 NOT_DEBUG_RETURN; 107 108 // Statistics. 109 static idx_t* _pop_count_table; 110 static void init_pop_count_table(); 111 static idx_t num_set_bits(bm_word_t w); 112 static idx_t num_set_bits_from_table(unsigned char c); 113 114 public: 115 116 // Constructs a bitmap with no map, and size 0. 117 BitMap() : _map(NULL), _size(0), _map_allocator(false) {} 118 119 // Constructs a bitmap with the given map and size. 120 BitMap(bm_word_t* map, idx_t size_in_bits); 121 122 // Constructs an empty bitmap of the given size (that is, this clears the 123 // new bitmap). Allocates the map array in resource area if 124 // "in_resource_area" is true, else in the C heap. 125 BitMap(idx_t size_in_bits, bool in_resource_area = true); 126 127 // Set the map and size. 128 void set_map(bm_word_t* map) { _map = map; } 129 void set_size(idx_t size_in_bits) { _size = size_in_bits; } 130 131 // Allocates necessary data structure, either in the resource area 132 // or in the C heap, as indicated by "in_resource_area." 133 // Preserves state currently in bit map by copying data. 134 // Zeros any newly-addressable bits. 135 // If "in_resource_area" is false, frees the current map. 136 // (Note that this assumes that all calls to "resize" on the same BitMap 137 // use the same value for "in_resource_area".) 138 void resize(idx_t size_in_bits, bool in_resource_area = true); 139 140 // Accessing 141 idx_t size() const { return _size; } 142 idx_t size_in_words() const { 143 return word_index(size() + BitsPerWord - 1); 144 } 145 146 bool at(idx_t index) const { 147 verify_index(index); 148 return (*word_addr(index) & bit_mask(index)) != 0; 149 } 150 151 // Align bit index up or down to the next bitmap word boundary, or check 152 // alignment. 153 static idx_t word_align_up(idx_t bit) { 154 return align_size_up(bit, BitsPerWord); 155 } 156 static idx_t word_align_down(idx_t bit) { 157 return align_size_down(bit, BitsPerWord); 158 } 159 static bool is_word_aligned(idx_t bit) { 160 return word_align_up(bit) == bit; 161 } 162 163 // Set or clear the specified bit. 164 inline void set_bit(idx_t bit); 165 inline void clear_bit(idx_t bit); 166 167 // Atomically set or clear the specified bit. 168 inline bool par_set_bit(idx_t bit); 169 inline bool par_clear_bit(idx_t bit); 170 171 // Put the given value at the given offset. The parallel version 172 // will CAS the value into the bitmap and is quite a bit slower. 173 // The parallel version also returns a value indicating if the 174 // calling thread was the one that changed the value of the bit. 175 void at_put(idx_t index, bool value); 176 bool par_at_put(idx_t index, bool value); 177 178 // Update a range of bits. Ranges are half-open [beg, end). 179 void set_range (idx_t beg, idx_t end); 180 void clear_range (idx_t beg, idx_t end); 181 void set_large_range (idx_t beg, idx_t end); 182 void clear_large_range (idx_t beg, idx_t end); 183 void at_put_range(idx_t beg, idx_t end, bool value); 184 void par_at_put_range(idx_t beg, idx_t end, bool value); 185 void at_put_large_range(idx_t beg, idx_t end, bool value); 186 void par_at_put_large_range(idx_t beg, idx_t end, bool value); 187 188 // Update a range of bits, using a hint about the size. Currently only 189 // inlines the predominant case of a 1-bit range. Works best when hint is a 190 // compile-time constant. 191 void set_range(idx_t beg, idx_t end, RangeSizeHint hint); 192 void clear_range(idx_t beg, idx_t end, RangeSizeHint hint); 193 void par_set_range(idx_t beg, idx_t end, RangeSizeHint hint); 194 void par_clear_range (idx_t beg, idx_t end, RangeSizeHint hint); 195 196 // Clearing 197 void clear_large(); 198 inline void clear(); 199 200 // Iteration support. Returns "true" if the iteration completed, false 201 // if the iteration terminated early (because the closure "blk" returned 202 // false). 203 bool iterate(BitMapClosure* blk, idx_t leftIndex, idx_t rightIndex); 204 bool iterate(BitMapClosure* blk) { 205 // call the version that takes an interval 206 return iterate(blk, 0, size()); 207 } 208 209 // Looking for 1's and 0's at indices equal to or greater than "l_index", 210 // stopping if none has been found before "r_index", and returning 211 // "r_index" (which must be at most "size") in that case. 212 idx_t get_next_one_offset_inline (idx_t l_index, idx_t r_index) const; 213 idx_t get_next_zero_offset_inline(idx_t l_index, idx_t r_index) const; 214 215 // Like "get_next_one_offset_inline", except requires that "r_index" is 216 // aligned to bitsizeof(bm_word_t). 217 idx_t get_next_one_offset_inline_aligned_right(idx_t l_index, 218 idx_t r_index) const; 219 220 // Non-inline versionsof the above. 221 idx_t get_next_one_offset (idx_t l_index, idx_t r_index) const; 222 idx_t get_next_zero_offset(idx_t l_index, idx_t r_index) const; 223 224 idx_t get_next_one_offset(idx_t offset) const { 225 return get_next_one_offset(offset, size()); 226 } 227 idx_t get_next_zero_offset(idx_t offset) const { 228 return get_next_zero_offset(offset, size()); 229 } 230 231 // Returns the number of bits set in the bitmap. 232 idx_t count_one_bits() const; 233 234 // Set operations. 235 void set_union(BitMap bits); 236 void set_difference(BitMap bits); 237 void set_intersection(BitMap bits); 238 // Returns true iff "this" is a superset of "bits". 239 bool contains(const BitMap bits) const; 240 // Returns true iff "this and "bits" have a non-empty intersection. 241 bool intersects(const BitMap bits) const; 242 243 // Returns result of whether this map changed 244 // during the operation 245 bool set_union_with_result(BitMap bits); 246 bool set_difference_with_result(BitMap bits); 247 bool set_intersection_with_result(BitMap bits); 248 249 // Requires the submap of "bits" starting at offset to be at least as 250 // large as "this". Modifies "this" to be the intersection of its 251 // current contents and the submap of "bits" starting at "offset" of the 252 // same length as "this." 253 // (For expedience, currently requires the offset to be aligned to the 254 // bitsize of a uintptr_t. This should go away in the future though it 255 // will probably remain a good case to optimize.) 256 void set_intersection_at_offset(BitMap bits, idx_t offset); 257 258 void set_from(BitMap bits); 259 260 bool is_same(BitMap bits); 261 262 // Test if all bits are set or cleared 263 bool is_full() const; 264 bool is_empty() const; 265 266 void print_on_error(outputStream* st, const char* prefix) const; 267 268 #ifndef PRODUCT 269 public: 270 // Printing 271 void print_on(outputStream* st) const; 272 #endif 273 }; 274 275 // Convenience class wrapping BitMap which provides multiple bits per slot. 276 class BitMap2D VALUE_OBJ_CLASS_SPEC { 277 public: 278 typedef BitMap::idx_t idx_t; // Type used for bit and word indices. 279 typedef BitMap::bm_word_t bm_word_t; // Element type of array that 280 // represents the bitmap. 281 private: 282 BitMap _map; 283 idx_t _bits_per_slot; 284 285 idx_t bit_index(idx_t slot_index, idx_t bit_within_slot_index) const { 286 return slot_index * _bits_per_slot + bit_within_slot_index; 287 } 288 289 void verify_bit_within_slot_index(idx_t index) const { 290 assert(index < _bits_per_slot, "bit_within_slot index out of bounds"); 291 } 292 293 public: 294 // Construction. bits_per_slot must be greater than 0. 295 BitMap2D(bm_word_t* map, idx_t size_in_slots, idx_t bits_per_slot); 296 297 // Allocates necessary data structure in resource area. bits_per_slot must be greater than 0. 298 BitMap2D(idx_t size_in_slots, idx_t bits_per_slot); 299 300 idx_t size_in_bits() { 301 return _map.size(); 302 } 303 304 // Returns number of full slots that have been allocated 305 idx_t size_in_slots() { 306 // Round down 307 return _map.size() / _bits_per_slot; 308 } 309 310 bool is_valid_index(idx_t slot_index, idx_t bit_within_slot_index) { 311 verify_bit_within_slot_index(bit_within_slot_index); 312 return (bit_index(slot_index, bit_within_slot_index) < size_in_bits()); 313 } 314 315 bool at(idx_t slot_index, idx_t bit_within_slot_index) const { 316 verify_bit_within_slot_index(bit_within_slot_index); 317 return _map.at(bit_index(slot_index, bit_within_slot_index)); 318 } 319 320 void set_bit(idx_t slot_index, idx_t bit_within_slot_index) { 321 verify_bit_within_slot_index(bit_within_slot_index); 322 _map.set_bit(bit_index(slot_index, bit_within_slot_index)); 323 } 324 325 void clear_bit(idx_t slot_index, idx_t bit_within_slot_index) { 326 verify_bit_within_slot_index(bit_within_slot_index); 327 _map.clear_bit(bit_index(slot_index, bit_within_slot_index)); 328 } 329 330 void at_put(idx_t slot_index, idx_t bit_within_slot_index, bool value) { 331 verify_bit_within_slot_index(bit_within_slot_index); 332 _map.at_put(bit_index(slot_index, bit_within_slot_index), value); 333 } 334 335 void at_put_grow(idx_t slot_index, idx_t bit_within_slot_index, bool value) { 336 verify_bit_within_slot_index(bit_within_slot_index); 337 _map.at_put_grow(bit_index(slot_index, bit_within_slot_index), value); 338 } 339 340 void clear(); 341 }; 342 343 // Closure for iterating over BitMaps 344 345 class BitMapClosure VALUE_OBJ_CLASS_SPEC { 346 public: 347 // Callback when bit in map is set. Should normally return "true"; 348 // return of false indicates that the bitmap iteration should terminate. 349 virtual bool do_bit(BitMap::idx_t offset) = 0; 350 }; 351 352 #endif // SHARE_VM_UTILITIES_BITMAP_HPP