1 /* 2 * Copyright (c) 1997, 2018, 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 "utilities/align.hpp" 29 30 // Forward decl; 31 class BitMapClosure; 32 33 // Operations for bitmaps represented as arrays of unsigned integers. 34 // Bit offsets are numbered from 0 to size-1. 35 36 // The "abstract" base BitMap class. 37 // 38 // The constructor and destructor are protected to prevent 39 // creation of BitMap instances outside of the BitMap class. 40 // 41 // The BitMap class doesn't use virtual calls on purpose, 42 // this ensures that we don't get a vtable unnecessarily. 43 // 44 // The allocation of the backing storage for the BitMap are handled by 45 // the subclasses. BitMap doesn't allocate or delete backing storage. 46 class BitMap { 47 friend class BitMap2D; 48 49 public: 50 typedef size_t idx_t; // Type used for bit and word indices. 51 typedef uintptr_t bm_word_t; // Element type of array that represents 52 // the bitmap. 53 54 // Hints for range sizes. 55 typedef enum { 56 unknown_range, small_range, large_range 57 } RangeSizeHint; 58 59 private: 60 bm_word_t* _map; // First word in bitmap 61 idx_t _size; // Size of bitmap (in bits) 62 63 protected: 64 // Return the position of bit within the word that contains it (e.g., if 65 // bitmap words are 32 bits, return a number 0 <= n <= 31). 66 static idx_t bit_in_word(idx_t bit) { return bit & (BitsPerWord - 1); } 67 68 // Return a mask that will select the specified bit, when applied to the word 69 // containing the bit. 70 static bm_word_t bit_mask(idx_t bit) { return (bm_word_t)1 << bit_in_word(bit); } 71 72 // Return the index of the word containing the specified bit. 73 static idx_t word_index(idx_t bit) { return bit >> LogBitsPerWord; } 74 75 // Return the bit number of the first bit in the specified word. 76 static idx_t bit_index(idx_t word) { return word << LogBitsPerWord; } 77 78 // Return the array of bitmap words, or a specific word from it. 79 bm_word_t* map() { return _map; } 80 const bm_word_t* map() const { return _map; } 81 bm_word_t map(idx_t word) const { return _map[word]; } 82 83 // Return a pointer to the word containing the specified bit. 84 bm_word_t* word_addr(idx_t bit) { return map() + word_index(bit); } 85 const bm_word_t* word_addr(idx_t bit) const { return map() + word_index(bit); } 86 87 // Set a word to a specified value or to all ones; clear a word. 88 void set_word (idx_t word, bm_word_t val) { _map[word] = val; } 89 void set_word (idx_t word) { set_word(word, ~(bm_word_t)0); } 90 void clear_word(idx_t word) { _map[word] = 0; } 91 92 // Utilities for ranges of bits. Ranges are half-open [beg, end). 93 94 // Ranges within a single word. 95 bm_word_t inverted_bit_mask_for_range(idx_t beg, idx_t end) const; 96 void set_range_within_word (idx_t beg, idx_t end); 97 void clear_range_within_word (idx_t beg, idx_t end); 98 void par_put_range_within_word (idx_t beg, idx_t end, bool value); 99 100 // Ranges spanning entire words. 101 void set_range_of_words (idx_t beg, idx_t end); 102 void clear_range_of_words (idx_t beg, idx_t end); 103 void set_large_range_of_words (idx_t beg, idx_t end); 104 void clear_large_range_of_words (idx_t beg, idx_t end); 105 106 static void clear_range_of_words(bm_word_t* map, idx_t beg, idx_t end); 107 108 // The index of the first full word in a range. 109 idx_t word_index_round_up(idx_t bit) const; 110 111 // Verification. 112 void verify_index(idx_t index) const NOT_DEBUG_RETURN; 113 void verify_range(idx_t beg_index, idx_t end_index) const NOT_DEBUG_RETURN; 114 115 // Statistics. 116 static const idx_t* _pop_count_table; 117 static void init_pop_count_table(); 118 static idx_t num_set_bits(bm_word_t w); 119 static idx_t num_set_bits_from_table(unsigned char c); 120 121 // Allocation Helpers. 122 123 // Allocates and clears the bitmap memory. 124 template <class Allocator> 125 static bm_word_t* allocate(const Allocator&, idx_t size_in_bits); 126 127 // Reallocates and clears the new bitmap memory. 128 template <class Allocator> 129 static bm_word_t* reallocate(const Allocator&, bm_word_t* map, idx_t old_size_in_bits, idx_t new_size_in_bits); 130 131 // Free the bitmap memory. 132 template <class Allocator> 133 static void free(const Allocator&, bm_word_t* map, idx_t size_in_bits); 134 135 // Protected functions, that are used by BitMap sub-classes that support them. 136 137 // Resize the backing bitmap memory. 138 // 139 // Old bits are transfered to the new memory 140 // and the extended memory is cleared. 141 template <class Allocator> 142 void resize(const Allocator& allocator, idx_t new_size_in_bits); 143 144 // Set up and clear the bitmap memory. 145 // 146 // Precondition: The bitmap was default constructed and has 147 // not yet had memory allocated via resize or (re)initialize. 148 template <class Allocator> 149 void initialize(const Allocator& allocator, idx_t size_in_bits); 150 151 // Set up and clear the bitmap memory. 152 // 153 // Can be called on previously initialized bitmaps. 154 template <class Allocator> 155 void reinitialize(const Allocator& allocator, idx_t new_size_in_bits); 156 157 // Set the map and size. 158 void update(bm_word_t* map, idx_t size) { 159 _map = map; 160 _size = size; 161 } 162 163 // Protected constructor and destructor. 164 BitMap(bm_word_t* map, idx_t size_in_bits) : _map(map), _size(size_in_bits) {} 165 ~BitMap() {} 166 167 public: 168 // Pretouch the entire range of memory this BitMap covers. 169 void pretouch(); 170 171 // Accessing 172 static idx_t calc_size_in_words(size_t size_in_bits) { 173 return word_index(size_in_bits + BitsPerWord - 1); 174 } 175 176 static idx_t calc_size_in_bytes(size_t size_in_bits) { 177 return calc_size_in_words(size_in_bits) * BytesPerWord; 178 } 179 180 idx_t size() const { return _size; } 181 idx_t size_in_words() const { return calc_size_in_words(size()); } 182 idx_t size_in_bytes() const { return calc_size_in_bytes(size()); } 183 184 bool at(idx_t index) const { 185 verify_index(index); 186 return (*word_addr(index) & bit_mask(index)) != 0; 187 } 188 189 // Align bit index up or down to the next bitmap word boundary, or check 190 // alignment. 191 static idx_t word_align_up(idx_t bit) { 192 return align_up(bit, BitsPerWord); 193 } 194 static idx_t word_align_down(idx_t bit) { 195 return align_down(bit, BitsPerWord); 196 } 197 static bool is_word_aligned(idx_t bit) { 198 return word_align_up(bit) == bit; 199 } 200 201 // Set or clear the specified bit. 202 inline void set_bit(idx_t bit); 203 inline void clear_bit(idx_t bit); 204 205 // Atomically set or clear the specified bit. 206 inline bool par_set_bit(idx_t bit); 207 inline bool par_clear_bit(idx_t bit); 208 209 // Put the given value at the given offset. The parallel version 210 // will CAS the value into the bitmap and is quite a bit slower. 211 // The parallel version also returns a value indicating if the 212 // calling thread was the one that changed the value of the bit. 213 void at_put(idx_t index, bool value); 214 bool par_at_put(idx_t index, bool value); 215 216 // Update a range of bits. Ranges are half-open [beg, end). 217 void set_range (idx_t beg, idx_t end); 218 void clear_range (idx_t beg, idx_t end); 219 void set_large_range (idx_t beg, idx_t end); 220 void clear_large_range (idx_t beg, idx_t end); 221 void at_put_range(idx_t beg, idx_t end, bool value); 222 void par_at_put_range(idx_t beg, idx_t end, bool value); 223 void at_put_large_range(idx_t beg, idx_t end, bool value); 224 void par_at_put_large_range(idx_t beg, idx_t end, bool value); 225 226 // Update a range of bits, using a hint about the size. Currently only 227 // inlines the predominant case of a 1-bit range. Works best when hint is a 228 // compile-time constant. 229 void set_range(idx_t beg, idx_t end, RangeSizeHint hint); 230 void clear_range(idx_t beg, idx_t end, RangeSizeHint hint); 231 void par_set_range(idx_t beg, idx_t end, RangeSizeHint hint); 232 void par_clear_range (idx_t beg, idx_t end, RangeSizeHint hint); 233 234 // Clearing 235 void clear_large(); 236 inline void clear(); 237 238 // Iteration support. Returns "true" if the iteration completed, false 239 // if the iteration terminated early (because the closure "blk" returned 240 // false). 241 bool iterate(BitMapClosure* blk, idx_t leftIndex, idx_t rightIndex); 242 bool iterate(BitMapClosure* blk) { 243 // call the version that takes an interval 244 return iterate(blk, 0, size()); 245 } 246 247 // Looking for 1's and 0's at indices equal to or greater than "l_index", 248 // stopping if none has been found before "r_index", and returning 249 // "r_index" (which must be at most "size") in that case. 250 idx_t get_next_one_offset (idx_t l_index, idx_t r_index) const; 251 idx_t get_next_zero_offset(idx_t l_index, idx_t r_index) const; 252 253 idx_t get_next_one_offset(idx_t offset) const { 254 return get_next_one_offset(offset, size()); 255 } 256 idx_t get_next_zero_offset(idx_t offset) const { 257 return get_next_zero_offset(offset, size()); 258 } 259 260 // Like "get_next_one_offset", except requires that "r_index" is 261 // aligned to bitsizeof(bm_word_t). 262 idx_t get_next_one_offset_aligned_right(idx_t l_index, idx_t r_index) const; 263 264 // Returns the number of bits set in the bitmap. 265 idx_t count_one_bits() const; 266 267 // Set operations. 268 void set_union(const BitMap& bits); 269 void set_difference(const BitMap& bits); 270 void set_intersection(const BitMap& bits); 271 // Returns true iff "this" is a superset of "bits". 272 bool contains(const BitMap& bits) const; 273 // Returns true iff "this and "bits" have a non-empty intersection. 274 bool intersects(const BitMap& bits) const; 275 276 // Returns result of whether this map changed 277 // during the operation 278 bool set_union_with_result(const BitMap& bits); 279 bool set_difference_with_result(const BitMap& bits); 280 bool set_intersection_with_result(const BitMap& bits); 281 282 void set_from(const BitMap& bits); 283 284 bool is_same(const BitMap& bits) const; 285 286 // Test if all bits are set or cleared 287 bool is_full() const; 288 bool is_empty() const; 289 290 void print_on_error(outputStream* st, const char* prefix) const; 291 292 #ifndef PRODUCT 293 public: 294 // Printing 295 void print_on(outputStream* st) const; 296 #endif 297 }; 298 299 // A concrete implementation of the the "abstract" BitMap class. 300 // 301 // The BitMapView is used when the backing storage is managed externally. 302 class BitMapView : public BitMap { 303 public: 304 BitMapView() : BitMap(NULL, 0) {} 305 BitMapView(bm_word_t* map, idx_t size_in_bits) : BitMap(map, size_in_bits) {} 306 }; 307 308 // A BitMap with storage in a ResourceArea. 309 class ResourceBitMap : public BitMap { 310 311 public: 312 ResourceBitMap() : BitMap(NULL, 0) {} 313 // Clears the bitmap memory. 314 ResourceBitMap(idx_t size_in_bits); 315 316 // Resize the backing bitmap memory. 317 // 318 // Old bits are transfered to the new memory 319 // and the extended memory is cleared. 320 void resize(idx_t new_size_in_bits); 321 322 // Set up and clear the bitmap memory. 323 // 324 // Precondition: The bitmap was default constructed and has 325 // not yet had memory allocated via resize or initialize. 326 void initialize(idx_t size_in_bits); 327 328 // Set up and clear the bitmap memory. 329 // 330 // Can be called on previously initialized bitmaps. 331 void reinitialize(idx_t size_in_bits); 332 }; 333 334 // A BitMap with storage in a specific Arena. 335 class ArenaBitMap : public BitMap { 336 public: 337 // Clears the bitmap memory. 338 ArenaBitMap(Arena* arena, idx_t size_in_bits); 339 340 private: 341 // Don't allow copy or assignment. 342 ArenaBitMap(const ArenaBitMap&); 343 ArenaBitMap& operator=(const ArenaBitMap&); 344 }; 345 346 // A BitMap with storage in the CHeap. 347 class CHeapBitMap : public BitMap { 348 349 private: 350 // Don't allow copy or assignment, to prevent the 351 // allocated memory from leaking out to other instances. 352 CHeapBitMap(const CHeapBitMap&); 353 CHeapBitMap& operator=(const CHeapBitMap&); 354 355 // NMT memory type 356 MEMFLAGS _flags; 357 358 public: 359 CHeapBitMap(MEMFLAGS flags = mtInternal) : BitMap(NULL, 0), _flags(flags) {} 360 // Clears the bitmap memory. 361 CHeapBitMap(idx_t size_in_bits, MEMFLAGS flags = mtInternal); 362 ~CHeapBitMap(); 363 364 // Resize the backing bitmap memory. 365 // 366 // Old bits are transfered to the new memory 367 // and the extended memory is cleared. 368 void resize(idx_t new_size_in_bits); 369 370 // Set up and clear the bitmap memory. 371 // 372 // Precondition: The bitmap was default constructed and has 373 // not yet had memory allocated via resize or initialize. 374 void initialize(idx_t size_in_bits); 375 376 // Set up and clear the bitmap memory. 377 // 378 // Can be called on previously initialized bitmaps. 379 void reinitialize(idx_t size_in_bits); 380 }; 381 382 // Convenience class wrapping BitMap which provides multiple bits per slot. 383 class BitMap2D { 384 public: 385 typedef BitMap::idx_t idx_t; // Type used for bit and word indices. 386 typedef BitMap::bm_word_t bm_word_t; // Element type of array that 387 // represents the bitmap. 388 private: 389 ResourceBitMap _map; 390 idx_t _bits_per_slot; 391 392 idx_t bit_index(idx_t slot_index, idx_t bit_within_slot_index) const { 393 return slot_index * _bits_per_slot + bit_within_slot_index; 394 } 395 396 void verify_bit_within_slot_index(idx_t index) const { 397 assert(index < _bits_per_slot, "bit_within_slot index out of bounds"); 398 } 399 400 public: 401 // Construction. bits_per_slot must be greater than 0. 402 BitMap2D(idx_t bits_per_slot) : 403 _map(), _bits_per_slot(bits_per_slot) {} 404 405 // Allocates necessary data structure in resource area. bits_per_slot must be greater than 0. 406 BitMap2D(idx_t size_in_slots, idx_t bits_per_slot) : 407 _map(size_in_slots * bits_per_slot), _bits_per_slot(bits_per_slot) {} 408 409 idx_t size_in_bits() { 410 return _map.size(); 411 } 412 413 // Returns number of full slots that have been allocated 414 idx_t size_in_slots() { 415 // Round down 416 return _map.size() / _bits_per_slot; 417 } 418 419 bool is_valid_index(idx_t slot_index, idx_t bit_within_slot_index); 420 bool at(idx_t slot_index, idx_t bit_within_slot_index) const; 421 void set_bit(idx_t slot_index, idx_t bit_within_slot_index); 422 void clear_bit(idx_t slot_index, idx_t bit_within_slot_index); 423 void at_put(idx_t slot_index, idx_t bit_within_slot_index, bool value); 424 void at_put_grow(idx_t slot_index, idx_t bit_within_slot_index, bool value); 425 }; 426 427 // Closure for iterating over BitMaps 428 429 class BitMapClosure { 430 public: 431 // Callback when bit in map is set. Should normally return "true"; 432 // return of false indicates that the bitmap iteration should terminate. 433 virtual bool do_bit(BitMap::idx_t offset) = 0; 434 }; 435 436 #endif // SHARE_VM_UTILITIES_BITMAP_HPP