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 "memory/allocation.hpp" 29 #include "utilities/align.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 // The "abstract" base BitMap class. 38 // 39 // The constructor and destructor are protected to prevent 40 // creation of BitMap instances outside of the BitMap class. 41 // 42 // The BitMap class doesn't use virtual calls on purpose, 43 // this ensures that we don't get a vtable unnecessarily. 44 // 45 // The allocation of the backing storage for the BitMap are handled by 46 // the subclasses. BitMap doesn't allocate or delete backing storage. 47 class BitMap { 48 friend class BitMap2D; 49 50 public: 51 typedef size_t idx_t; // Type used for bit and word indices. 52 typedef uintptr_t bm_word_t; // Element type of array that represents 53 // the bitmap. 54 55 // Hints for range sizes. 56 typedef enum { 57 unknown_range, small_range, large_range 58 } RangeSizeHint; 59 60 private: 61 bm_word_t* _map; // First word in bitmap 62 idx_t _size; // Size of bitmap (in bits) 63 64 protected: 65 // Return the position of bit within the word that contains it (e.g., if 66 // bitmap words are 32 bits, return a number 0 <= n <= 31). 67 static idx_t bit_in_word(idx_t bit) { return bit & (BitsPerWord - 1); } 68 69 // Return a mask that will select the specified bit, when applied to the word 70 // containing the bit. 71 static bm_word_t bit_mask(idx_t bit) { return (bm_word_t)1 << bit_in_word(bit); } 72 73 // Return the index of the word containing the specified bit. 74 static idx_t word_index(idx_t bit) { return bit >> LogBitsPerWord; } 75 76 // Return the bit number of the first bit in the specified word. 77 static idx_t bit_index(idx_t word) { return word << LogBitsPerWord; } 78 79 // Return the array of bitmap words, or a specific word from it. 80 bm_word_t* map() { return _map; } 81 const bm_word_t* map() const { return _map; } 82 bm_word_t map(idx_t word) const { return _map[word]; } 83 84 // Return a pointer to the word containing the specified bit. 85 bm_word_t* word_addr(idx_t bit) { return map() + word_index(bit); } 86 const bm_word_t* word_addr(idx_t bit) const { return map() + word_index(bit); } 87 88 // Set a word to a specified value or to all ones; clear a word. 89 void set_word (idx_t word, bm_word_t val) { _map[word] = val; } 90 void set_word (idx_t word) { set_word(word, ~(bm_word_t)0); } 91 void clear_word(idx_t word) { _map[word] = 0; } 92 93 // Utilities for ranges of bits. Ranges are half-open [beg, end). 94 95 // Ranges within a single word. 96 bm_word_t inverted_bit_mask_for_range(idx_t beg, idx_t end) const; 97 void set_range_within_word (idx_t beg, idx_t end); 98 void clear_range_within_word (idx_t beg, idx_t end); 99 void par_put_range_within_word (idx_t beg, idx_t end, bool value); 100 101 // Ranges spanning entire words. 102 void set_range_of_words (idx_t beg, idx_t end); 103 void clear_range_of_words (idx_t beg, idx_t end); 104 void set_large_range_of_words (idx_t beg, idx_t end); 105 void clear_large_range_of_words (idx_t beg, idx_t end); 106 107 static void clear_range_of_words(bm_word_t* map, idx_t beg, idx_t end); 108 109 // The index of the first full word in a range. 110 idx_t word_index_round_up(idx_t bit) const; 111 112 // Verification. 113 void verify_index(idx_t index) const NOT_DEBUG_RETURN; 114 void verify_range(idx_t beg_index, idx_t end_index) const NOT_DEBUG_RETURN; 115 116 // Statistics. 117 static const idx_t* _pop_count_table; 118 static void init_pop_count_table(); 119 static idx_t num_set_bits(bm_word_t w); 120 static idx_t num_set_bits_from_table(unsigned char c); 121 122 // Allocation Helpers. 123 124 // Allocates and clears the bitmap memory. 125 template <class Allocator> 126 static bm_word_t* allocate(const Allocator&, idx_t size_in_bits); 127 128 // Reallocates and clears the new bitmap memory. 129 template <class Allocator> 130 static bm_word_t* reallocate(const Allocator&, bm_word_t* map, idx_t old_size_in_bits, idx_t new_size_in_bits); 131 132 // Free the bitmap memory. 133 template <class Allocator> 134 static void free(const Allocator&, bm_word_t* map, idx_t size_in_bits); 135 136 // Protected functions, that are used by BitMap sub-classes that support them. 137 138 // Resize the backing bitmap memory. 139 // 140 // Old bits are transfered to the new memory 141 // and the extended memory is cleared. 142 template <class Allocator> 143 void resize(const Allocator& allocator, idx_t new_size_in_bits); 144 145 // Set up and clear the bitmap memory. 146 // 147 // Precondition: The bitmap was default constructed and has 148 // not yet had memory allocated via resize or (re)initialize. 149 template <class Allocator> 150 void initialize(const Allocator& allocator, idx_t size_in_bits); 151 152 // Set up and clear the bitmap memory. 153 // 154 // Can be called on previously initialized bitmaps. 155 template <class Allocator> 156 void reinitialize(const Allocator& allocator, idx_t new_size_in_bits); 157 158 // Set the map and size. 159 void update(bm_word_t* map, idx_t size) { 160 _map = map; 161 _size = size; 162 } 163 164 // Protected constructor and destructor. 165 BitMap(bm_word_t* map, idx_t size_in_bits) : _map(map), _size(size_in_bits) {} 166 ~BitMap() {} 167 168 public: 169 // Pretouch the entire range of memory this BitMap covers. 170 void pretouch(); 171 172 // Accessing 173 static idx_t calc_size_in_words(size_t size_in_bits) { 174 return word_index(size_in_bits + BitsPerWord - 1); 175 } 176 177 static idx_t calc_size_in_bytes(size_t size_in_bits) { 178 return calc_size_in_words(size_in_bits) * BytesPerWord; 179 } 180 181 idx_t size() const { return _size; } 182 idx_t size_in_words() const { return calc_size_in_words(size()); } 183 idx_t size_in_bytes() const { return calc_size_in_bytes(size()); } 184 185 bool at(idx_t index) const { 186 verify_index(index); 187 return (*word_addr(index) & bit_mask(index)) != 0; 188 } 189 190 // Align bit index up or down to the next bitmap word boundary, or check 191 // alignment. 192 static idx_t word_align_up(idx_t bit) { 193 return align_up(bit, BitsPerWord); 194 } 195 static idx_t word_align_down(idx_t bit) { 196 return align_down(bit, BitsPerWord); 197 } 198 static bool is_word_aligned(idx_t bit) { 199 return word_align_up(bit) == bit; 200 } 201 202 // Set or clear the specified bit. 203 inline void set_bit(idx_t bit); 204 inline void clear_bit(idx_t bit); 205 206 // Atomically set or clear the specified bit. 207 inline bool par_set_bit(idx_t bit); 208 inline bool par_clear_bit(idx_t bit); 209 210 // Put the given value at the given offset. The parallel version 211 // will CAS the value into the bitmap and is quite a bit slower. 212 // The parallel version also returns a value indicating if the 213 // calling thread was the one that changed the value of the bit. 214 void at_put(idx_t index, bool value); 215 bool par_at_put(idx_t index, bool value); 216 217 // Update a range of bits. Ranges are half-open [beg, end). 218 void set_range (idx_t beg, idx_t end); 219 void clear_range (idx_t beg, idx_t end); 220 void set_large_range (idx_t beg, idx_t end); 221 void clear_large_range (idx_t beg, idx_t end); 222 void at_put_range(idx_t beg, idx_t end, bool value); 223 void par_at_put_range(idx_t beg, idx_t end, bool value); 224 void at_put_large_range(idx_t beg, idx_t end, bool value); 225 void par_at_put_large_range(idx_t beg, idx_t end, bool value); 226 227 // Update a range of bits, using a hint about the size. Currently only 228 // inlines the predominant case of a 1-bit range. Works best when hint is a 229 // compile-time constant. 230 void set_range(idx_t beg, idx_t end, RangeSizeHint hint); 231 void clear_range(idx_t beg, idx_t end, RangeSizeHint hint); 232 void par_set_range(idx_t beg, idx_t end, RangeSizeHint hint); 233 void par_clear_range (idx_t beg, idx_t end, RangeSizeHint hint); 234 235 // Clearing 236 void clear_large(); 237 inline void clear(); 238 239 // Copying 240 void copy_from(BitMap& other, size_t start, size_t end); 241 242 // Iteration support. Returns "true" if the iteration completed, false 243 // if the iteration terminated early (because the closure "blk" returned 244 // false). 245 bool iterate(BitMapClosure* blk, idx_t leftIndex, idx_t rightIndex); 246 bool iterate(BitMapClosure* blk) { 247 // call the version that takes an interval 248 return iterate(blk, 0, size()); 249 } 250 251 // Looking for 1's and 0's at indices equal to or greater than "l_index", 252 // stopping if none has been found before "r_index", and returning 253 // "r_index" (which must be at most "size") in that case. 254 idx_t get_next_one_offset (idx_t l_index, idx_t r_index) const; 255 idx_t get_next_zero_offset(idx_t l_index, idx_t r_index) const; 256 257 idx_t get_next_one_offset(idx_t offset) const { 258 return get_next_one_offset(offset, size()); 259 } 260 idx_t get_next_zero_offset(idx_t offset) const { 261 return get_next_zero_offset(offset, size()); 262 } 263 264 // Like "get_next_one_offset", except requires that "r_index" is 265 // aligned to bitsizeof(bm_word_t). 266 idx_t get_next_one_offset_aligned_right(idx_t l_index, idx_t r_index) const; 267 268 // Returns the number of bits set in the bitmap. 269 idx_t count_one_bits() const; 270 271 // Set operations. 272 void set_union(const BitMap& bits); 273 void set_difference(const BitMap& bits); 274 void set_intersection(const BitMap& bits); 275 // Returns true iff "this" is a superset of "bits". 276 bool contains(const BitMap& bits) const; 277 // Returns true iff "this and "bits" have a non-empty intersection. 278 bool intersects(const BitMap& bits) const; 279 280 // Returns result of whether this map changed 281 // during the operation 282 bool set_union_with_result(const BitMap& bits); 283 bool set_difference_with_result(const BitMap& bits); 284 bool set_intersection_with_result(const BitMap& bits); 285 286 void set_from(const BitMap& bits); 287 288 bool is_same(const BitMap& bits) const; 289 290 // Test if all bits are set or cleared 291 bool is_full() const; 292 bool is_empty() const; 293 294 void print_on_error(outputStream* st, const char* prefix) const; 295 296 #ifndef PRODUCT 297 public: 298 // Printing 299 void print_on(outputStream* st) const; 300 #endif 301 }; 302 303 // A concrete implementation of the the "abstract" BitMap class. 304 // 305 // The BitMapView is used when the backing storage is managed externally. 306 class BitMapView : public BitMap { 307 public: 308 BitMapView() : BitMap(NULL, 0) {} 309 BitMapView(bm_word_t* map, idx_t size_in_bits) : BitMap(map, size_in_bits) {} 310 }; 311 312 // A BitMap with storage in a ResourceArea. 313 class ResourceBitMap : public BitMap { 314 315 public: 316 ResourceBitMap() : BitMap(NULL, 0) {} 317 // Clears the bitmap memory. 318 ResourceBitMap(idx_t size_in_bits); 319 320 // Resize the backing bitmap memory. 321 // 322 // Old bits are transfered to the new memory 323 // and the extended memory is cleared. 324 void resize(idx_t new_size_in_bits); 325 326 // Set up and clear the bitmap memory. 327 // 328 // Precondition: The bitmap was default constructed and has 329 // not yet had memory allocated via resize or initialize. 330 void initialize(idx_t size_in_bits); 331 332 // Set up and clear the bitmap memory. 333 // 334 // Can be called on previously initialized bitmaps. 335 void reinitialize(idx_t size_in_bits); 336 }; 337 338 // A BitMap with storage in a specific Arena. 339 class ArenaBitMap : public BitMap { 340 public: 341 // Clears the bitmap memory. 342 ArenaBitMap(Arena* arena, idx_t size_in_bits); 343 344 private: 345 // Don't allow copy or assignment. 346 ArenaBitMap(const ArenaBitMap&); 347 ArenaBitMap& operator=(const ArenaBitMap&); 348 }; 349 350 // A BitMap with storage in the CHeap. 351 class CHeapBitMap : public BitMap { 352 353 private: 354 // Don't allow copy or assignment, to prevent the 355 // allocated memory from leaking out to other instances. 356 CHeapBitMap(const CHeapBitMap&); 357 CHeapBitMap& operator=(const CHeapBitMap&); 358 359 // NMT memory type 360 MEMFLAGS _flags; 361 362 public: 363 CHeapBitMap(MEMFLAGS flags = mtInternal) : BitMap(NULL, 0), _flags(flags) {} 364 // Clears the bitmap memory. 365 CHeapBitMap(idx_t size_in_bits, MEMFLAGS flags = mtInternal); 366 ~CHeapBitMap(); 367 368 // Resize the backing bitmap memory. 369 // 370 // Old bits are transfered to the new memory 371 // and the extended memory is cleared. 372 void resize(idx_t new_size_in_bits); 373 374 // Set up and clear the bitmap memory. 375 // 376 // Precondition: The bitmap was default constructed and has 377 // not yet had memory allocated via resize or initialize. 378 void initialize(idx_t size_in_bits); 379 380 // Set up and clear the bitmap memory. 381 // 382 // Can be called on previously initialized bitmaps. 383 void reinitialize(idx_t size_in_bits); 384 }; 385 386 // Convenience class wrapping BitMap which provides multiple bits per slot. 387 class BitMap2D { 388 public: 389 typedef BitMap::idx_t idx_t; // Type used for bit and word indices. 390 typedef BitMap::bm_word_t bm_word_t; // Element type of array that 391 // represents the bitmap. 392 private: 393 ResourceBitMap _map; 394 idx_t _bits_per_slot; 395 396 idx_t bit_index(idx_t slot_index, idx_t bit_within_slot_index) const { 397 return slot_index * _bits_per_slot + bit_within_slot_index; 398 } 399 400 void verify_bit_within_slot_index(idx_t index) const { 401 assert(index < _bits_per_slot, "bit_within_slot index out of bounds"); 402 } 403 404 public: 405 // Construction. bits_per_slot must be greater than 0. 406 BitMap2D(idx_t bits_per_slot) : 407 _map(), _bits_per_slot(bits_per_slot) {} 408 409 // Allocates necessary data structure in resource area. bits_per_slot must be greater than 0. 410 BitMap2D(idx_t size_in_slots, idx_t bits_per_slot) : 411 _map(size_in_slots * bits_per_slot), _bits_per_slot(bits_per_slot) {} 412 413 idx_t size_in_bits() { 414 return _map.size(); 415 } 416 417 // Returns number of full slots that have been allocated 418 idx_t size_in_slots() { 419 // Round down 420 return _map.size() / _bits_per_slot; 421 } 422 423 bool is_valid_index(idx_t slot_index, idx_t bit_within_slot_index); 424 bool at(idx_t slot_index, idx_t bit_within_slot_index) const; 425 void set_bit(idx_t slot_index, idx_t bit_within_slot_index); 426 void clear_bit(idx_t slot_index, idx_t bit_within_slot_index); 427 void at_put(idx_t slot_index, idx_t bit_within_slot_index, bool value); 428 void at_put_grow(idx_t slot_index, idx_t bit_within_slot_index, bool value); 429 }; 430 431 // Closure for iterating over BitMaps 432 433 class BitMapClosure { 434 public: 435 // Callback when bit in map is set. Should normally return "true"; 436 // return of false indicates that the bitmap iteration should terminate. 437 virtual bool do_bit(BitMap::idx_t offset) = 0; 438 }; 439 440 #endif // SHARE_VM_UTILITIES_BITMAP_HPP