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