1 /* 2 * Copyright (c) 1997, 2019, 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_UTILITIES_BITMAP_HPP 26 #define SHARE_UTILITIES_BITMAP_HPP 27 28 #include "memory/allocation.hpp" 29 #include "utilities/align.hpp" 30 #include "utilities/globalDefinitions.hpp" 31 32 // Forward decl; 33 class BitMapClosure; 34 35 // Operations for bitmaps represented as arrays of unsigned integers. 36 // Bit offsets are numbered from 0 to size-1. 37 38 // The "abstract" base BitMap class. 39 // 40 // The constructor and destructor are protected to prevent 41 // creation of BitMap instances outside of the BitMap class. 42 // 43 // The BitMap class doesn't use virtual calls on purpose, 44 // this ensures that we don't get a vtable unnecessarily. 45 // 46 // The allocation of the backing storage for the BitMap are handled by 47 // the subclasses. BitMap doesn't allocate or delete backing storage. 48 class BitMap { 49 friend class BitMap2D; 50 51 public: 52 typedef size_t idx_t; // Type used for bit and word indices. 53 typedef uintptr_t bm_word_t; // Element type of array that represents 54 // the bitmap. 55 56 // Hints for range sizes. 57 typedef enum { 58 unknown_range, small_range, large_range 59 } RangeSizeHint; 60 61 private: 62 bm_word_t* _map; // First word in bitmap 63 idx_t _size; // Size of bitmap (in bits) 64 65 // Helper for get_next_{zero,one}_bit variants. 66 // - flip designates whether searching for 1s or 0s. Must be one of 67 // find_{zeros,ones}_flip. 68 // - aligned_right is true if r_index is a priori on a bm_word_t boundary. 69 template<bm_word_t flip, bool aligned_right> 70 inline idx_t get_next_bit_impl(idx_t l_index, idx_t r_index) const; 71 72 // Values for get_next_bit_impl flip parameter. 73 static const bm_word_t find_ones_flip = 0; 74 static const bm_word_t find_zeros_flip = ~(bm_word_t)0; 75 76 // Threshold for performing small range operation, even when large range 77 // operation was requested. Measured in words. 78 static const size_t small_range_words = 32; 79 80 protected: 81 // Return the position of bit within the word that contains it (e.g., if 82 // bitmap words are 32 bits, return a number 0 <= n <= 31). bit_in_word(idx_t bit)83 static idx_t bit_in_word(idx_t bit) { return bit & (BitsPerWord - 1); } 84 85 // Return a mask that will select the specified bit, when applied to the word 86 // containing the bit. bit_mask(idx_t bit)87 static bm_word_t bit_mask(idx_t bit) { return (bm_word_t)1 << bit_in_word(bit); } 88 89 // Return the index of the word containing the specified bit. word_index(idx_t bit)90 static idx_t word_index(idx_t bit) { return bit >> LogBitsPerWord; } 91 92 // Return the bit number of the first bit in the specified word. bit_index(idx_t word)93 static idx_t bit_index(idx_t word) { return word << LogBitsPerWord; } 94 95 // Return the array of bitmap words, or a specific word from it. map()96 bm_word_t* map() { return _map; } map() const97 const bm_word_t* map() const { return _map; } map(idx_t word) const98 bm_word_t map(idx_t word) const { return _map[word]; } 99 100 // Return a pointer to the word containing the specified bit. word_addr(idx_t bit)101 bm_word_t* word_addr(idx_t bit) { return map() + word_index(bit); } word_addr(idx_t bit) const102 const bm_word_t* word_addr(idx_t bit) const { return map() + word_index(bit); } 103 104 // Set a word to a specified value or to all ones; clear a word. set_word(idx_t word,bm_word_t val)105 void set_word (idx_t word, bm_word_t val) { _map[word] = val; } set_word(idx_t word)106 void set_word (idx_t word) { set_word(word, ~(bm_word_t)0); } clear_word(idx_t word)107 void clear_word(idx_t word) { _map[word] = 0; } 108 109 // Utilities for ranges of bits. Ranges are half-open [beg, end). 110 111 // Ranges within a single word. 112 bm_word_t inverted_bit_mask_for_range(idx_t beg, idx_t end) const; 113 void set_range_within_word (idx_t beg, idx_t end); 114 void clear_range_within_word (idx_t beg, idx_t end); 115 void par_put_range_within_word (idx_t beg, idx_t end, bool value); 116 117 // Ranges spanning entire words. 118 void set_range_of_words (idx_t beg, idx_t end); 119 void clear_range_of_words (idx_t beg, idx_t end); 120 void set_large_range_of_words (idx_t beg, idx_t end); 121 void clear_large_range_of_words (idx_t beg, idx_t end); 122 123 static void clear_range_of_words(bm_word_t* map, idx_t beg, idx_t end); 124 125 static bool is_small_range_of_words(idx_t beg_full_word, idx_t end_full_word); 126 127 // The index of the first full word in a range. 128 idx_t word_index_round_up(idx_t bit) const; 129 130 // Verification. 131 void verify_index(idx_t index) const NOT_DEBUG_RETURN; 132 void verify_range(idx_t beg_index, idx_t end_index) const NOT_DEBUG_RETURN; 133 134 // Statistics. 135 static const idx_t* _pop_count_table; 136 static void init_pop_count_table(); 137 static idx_t num_set_bits(bm_word_t w); 138 static idx_t num_set_bits_from_table(unsigned char c); 139 140 // Allocation Helpers. 141 142 // Allocates and clears the bitmap memory. 143 template <class Allocator> 144 static bm_word_t* allocate(const Allocator&, idx_t size_in_bits, bool clear = true); 145 146 // Reallocates and clears the new bitmap memory. 147 template <class Allocator> 148 static bm_word_t* reallocate(const Allocator&, bm_word_t* map, idx_t old_size_in_bits, idx_t new_size_in_bits, bool clear = true); 149 150 // Free the bitmap memory. 151 template <class Allocator> 152 static void free(const Allocator&, bm_word_t* map, idx_t size_in_bits); 153 154 // Protected functions, that are used by BitMap sub-classes that support them. 155 156 // Resize the backing bitmap memory. 157 // 158 // Old bits are transfered to the new memory 159 // and the extended memory is cleared. 160 template <class Allocator> 161 void resize(const Allocator& allocator, idx_t new_size_in_bits, bool clear); 162 163 // Set up and clear the bitmap memory. 164 // 165 // Precondition: The bitmap was default constructed and has 166 // not yet had memory allocated via resize or (re)initialize. 167 template <class Allocator> 168 void initialize(const Allocator& allocator, idx_t size_in_bits, bool clear); 169 170 // Set up and clear the bitmap memory. 171 // 172 // Can be called on previously initialized bitmaps. 173 template <class Allocator> 174 void reinitialize(const Allocator& allocator, idx_t new_size_in_bits, bool clear); 175 176 // Set the map and size. update(bm_word_t * map,idx_t size)177 void update(bm_word_t* map, idx_t size) { 178 _map = map; 179 _size = size; 180 } 181 182 // Protected constructor and destructor. BitMap(bm_word_t * map,idx_t size_in_bits)183 BitMap(bm_word_t* map, idx_t size_in_bits) : _map(map), _size(size_in_bits) {} ~BitMap()184 ~BitMap() {} 185 186 public: 187 // Pretouch the entire range of memory this BitMap covers. 188 void pretouch(); 189 190 // Accessing calc_size_in_words(size_t size_in_bits)191 static idx_t calc_size_in_words(size_t size_in_bits) { 192 return word_index(size_in_bits + BitsPerWord - 1); 193 } 194 calc_size_in_bytes(size_t size_in_bits)195 static idx_t calc_size_in_bytes(size_t size_in_bits) { 196 return calc_size_in_words(size_in_bits) * BytesPerWord; 197 } 198 size() const199 idx_t size() const { return _size; } size_in_words() const200 idx_t size_in_words() const { return calc_size_in_words(size()); } size_in_bytes() const201 idx_t size_in_bytes() const { return calc_size_in_bytes(size()); } 202 at(idx_t index) const203 bool at(idx_t index) const { 204 verify_index(index); 205 return (*word_addr(index) & bit_mask(index)) != 0; 206 } 207 208 // Align bit index up or down to the next bitmap word boundary, or check 209 // alignment. word_align_up(idx_t bit)210 static idx_t word_align_up(idx_t bit) { 211 return align_up(bit, BitsPerWord); 212 } word_align_down(idx_t bit)213 static idx_t word_align_down(idx_t bit) { 214 return align_down(bit, BitsPerWord); 215 } is_word_aligned(idx_t bit)216 static bool is_word_aligned(idx_t bit) { 217 return word_align_up(bit) == bit; 218 } 219 220 // Set or clear the specified bit. 221 inline void set_bit(idx_t bit); 222 inline void clear_bit(idx_t bit); 223 224 // Atomically set or clear the specified bit. 225 inline bool par_set_bit(idx_t bit); 226 inline bool par_clear_bit(idx_t bit); 227 228 // Put the given value at the given offset. The parallel version 229 // will CAS the value into the bitmap and is quite a bit slower. 230 // The parallel version also returns a value indicating if the 231 // calling thread was the one that changed the value of the bit. 232 void at_put(idx_t index, bool value); 233 bool par_at_put(idx_t index, bool value); 234 235 // Update a range of bits. Ranges are half-open [beg, end). 236 void set_range (idx_t beg, idx_t end); 237 void clear_range (idx_t beg, idx_t end); 238 void set_large_range (idx_t beg, idx_t end); 239 void clear_large_range (idx_t beg, idx_t end); 240 void at_put_range(idx_t beg, idx_t end, bool value); 241 void par_at_put_range(idx_t beg, idx_t end, bool value); 242 void at_put_large_range(idx_t beg, idx_t end, bool value); 243 void par_at_put_large_range(idx_t beg, idx_t end, bool value); 244 245 // Update a range of bits, using a hint about the size. Currently only 246 // inlines the predominant case of a 1-bit range. Works best when hint is a 247 // compile-time constant. 248 void set_range(idx_t beg, idx_t end, RangeSizeHint hint); 249 void clear_range(idx_t beg, idx_t end, RangeSizeHint hint); 250 void par_set_range(idx_t beg, idx_t end, RangeSizeHint hint); 251 void par_clear_range (idx_t beg, idx_t end, RangeSizeHint hint); 252 253 // Clearing 254 void clear_large(); 255 inline void clear(); 256 257 // Iteration support. Returns "true" if the iteration completed, false 258 // if the iteration terminated early (because the closure "blk" returned 259 // false). 260 bool iterate(BitMapClosure* blk, idx_t leftIndex, idx_t rightIndex); iterate(BitMapClosure * blk)261 bool iterate(BitMapClosure* blk) { 262 // call the version that takes an interval 263 return iterate(blk, 0, size()); 264 } 265 266 // Looking for 1's and 0's at indices equal to or greater than "l_index", 267 // stopping if none has been found before "r_index", and returning 268 // "r_index" (which must be at most "size") in that case. 269 idx_t get_next_one_offset (idx_t l_index, idx_t r_index) const; 270 idx_t get_next_zero_offset(idx_t l_index, idx_t r_index) const; 271 get_next_one_offset(idx_t offset) const272 idx_t get_next_one_offset(idx_t offset) const { 273 return get_next_one_offset(offset, size()); 274 } get_next_zero_offset(idx_t offset) const275 idx_t get_next_zero_offset(idx_t offset) const { 276 return get_next_zero_offset(offset, size()); 277 } 278 279 // Like "get_next_one_offset", except requires that "r_index" is 280 // aligned to bitsizeof(bm_word_t). 281 idx_t get_next_one_offset_aligned_right(idx_t l_index, idx_t r_index) const; 282 283 // Returns the number of bits set in the bitmap. 284 idx_t count_one_bits() const; 285 286 // Set operations. 287 void set_union(const BitMap& bits); 288 void set_difference(const BitMap& bits); 289 void set_intersection(const BitMap& bits); 290 // Returns true iff "this" is a superset of "bits". 291 bool contains(const BitMap& bits) const; 292 // Returns true iff "this and "bits" have a non-empty intersection. 293 bool intersects(const BitMap& bits) const; 294 295 // Returns result of whether this map changed 296 // during the operation 297 bool set_union_with_result(const BitMap& bits); 298 bool set_difference_with_result(const BitMap& bits); 299 bool set_intersection_with_result(const BitMap& bits); 300 301 void set_from(const BitMap& bits); 302 303 bool is_same(const BitMap& bits) const; 304 305 // Test if all bits are set or cleared 306 bool is_full() const; 307 bool is_empty() const; 308 309 void write_to(bm_word_t* buffer, size_t buffer_size_in_bytes) const; 310 void print_on_error(outputStream* st, const char* prefix) const; 311 312 #ifndef PRODUCT 313 public: 314 // Printing 315 void print_on(outputStream* st) const; 316 #endif 317 }; 318 319 // A concrete implementation of the the "abstract" BitMap class. 320 // 321 // The BitMapView is used when the backing storage is managed externally. 322 class BitMapView : public BitMap { 323 public: BitMapView()324 BitMapView() : BitMap(NULL, 0) {} BitMapView(bm_word_t * map,idx_t size_in_bits)325 BitMapView(bm_word_t* map, idx_t size_in_bits) : BitMap(map, size_in_bits) {} 326 }; 327 328 // A BitMap with storage in a ResourceArea. 329 class ResourceBitMap : public BitMap { 330 331 public: ResourceBitMap()332 ResourceBitMap() : BitMap(NULL, 0) {} 333 // Conditionally clears the bitmap memory. 334 ResourceBitMap(idx_t size_in_bits, bool clear = true); 335 336 // Resize the backing bitmap memory. 337 // 338 // Old bits are transfered to the new memory 339 // and the extended memory is cleared. 340 void resize(idx_t new_size_in_bits); 341 342 // Set up and clear the bitmap memory. 343 // 344 // Precondition: The bitmap was default constructed and has 345 // not yet had memory allocated via resize or initialize. 346 void initialize(idx_t size_in_bits); 347 348 // Set up and clear the bitmap memory. 349 // 350 // Can be called on previously initialized bitmaps. 351 void reinitialize(idx_t size_in_bits); 352 }; 353 354 // A BitMap with storage in a specific Arena. 355 class ArenaBitMap : public BitMap { 356 public: 357 // Clears the bitmap memory. 358 ArenaBitMap(Arena* arena, idx_t size_in_bits); 359 360 private: 361 NONCOPYABLE(ArenaBitMap); 362 }; 363 364 // A BitMap with storage in the CHeap. 365 class CHeapBitMap : public BitMap { 366 367 private: 368 // Don't allow copy or assignment, to prevent the 369 // allocated memory from leaking out to other instances. 370 NONCOPYABLE(CHeapBitMap); 371 372 // NMT memory type 373 MEMFLAGS _flags; 374 375 public: CHeapBitMap(MEMFLAGS flags=mtInternal)376 CHeapBitMap(MEMFLAGS flags = mtInternal) : BitMap(NULL, 0), _flags(flags) {} 377 // Clears the bitmap memory. 378 CHeapBitMap(idx_t size_in_bits, MEMFLAGS flags = mtInternal, bool clear = true); 379 ~CHeapBitMap(); 380 381 // Resize the backing bitmap memory. 382 // 383 // Old bits are transfered to the new memory 384 // and the extended memory is (optionally) cleared. 385 void resize(idx_t new_size_in_bits, bool clear = true); 386 387 // Set up and (optionally) clear the bitmap memory. 388 // 389 // Precondition: The bitmap was default constructed and has 390 // not yet had memory allocated via resize or initialize. 391 void initialize(idx_t size_in_bits, bool clear = true); 392 393 // Set up and (optionally) clear the bitmap memory. 394 // 395 // Can be called on previously initialized bitmaps. 396 void reinitialize(idx_t size_in_bits, bool clear = true); 397 }; 398 399 // Convenience class wrapping BitMap which provides multiple bits per slot. 400 class BitMap2D { 401 public: 402 typedef BitMap::idx_t idx_t; // Type used for bit and word indices. 403 typedef BitMap::bm_word_t bm_word_t; // Element type of array that 404 // represents the bitmap. 405 private: 406 ResourceBitMap _map; 407 idx_t _bits_per_slot; 408 bit_index(idx_t slot_index,idx_t bit_within_slot_index) const409 idx_t bit_index(idx_t slot_index, idx_t bit_within_slot_index) const { 410 return slot_index * _bits_per_slot + bit_within_slot_index; 411 } 412 verify_bit_within_slot_index(idx_t index) const413 void verify_bit_within_slot_index(idx_t index) const { 414 assert(index < _bits_per_slot, "bit_within_slot index out of bounds"); 415 } 416 417 public: 418 // Construction. bits_per_slot must be greater than 0. BitMap2D(idx_t bits_per_slot)419 BitMap2D(idx_t bits_per_slot) : 420 _map(), _bits_per_slot(bits_per_slot) {} 421 422 // Allocates necessary data structure in resource area. bits_per_slot must be greater than 0. BitMap2D(idx_t size_in_slots,idx_t bits_per_slot)423 BitMap2D(idx_t size_in_slots, idx_t bits_per_slot) : 424 _map(size_in_slots * bits_per_slot), _bits_per_slot(bits_per_slot) {} 425 size_in_bits()426 idx_t size_in_bits() { 427 return _map.size(); 428 } 429 430 bool is_valid_index(idx_t slot_index, idx_t bit_within_slot_index); 431 bool at(idx_t slot_index, idx_t bit_within_slot_index) const; 432 void set_bit(idx_t slot_index, idx_t bit_within_slot_index); 433 void clear_bit(idx_t slot_index, idx_t bit_within_slot_index); 434 void at_put(idx_t slot_index, idx_t bit_within_slot_index, bool value); 435 void at_put_grow(idx_t slot_index, idx_t bit_within_slot_index, bool value); 436 }; 437 438 // Closure for iterating over BitMaps 439 440 class BitMapClosure { 441 public: 442 // Callback when bit in map is set. Should normally return "true"; 443 // return of false indicates that the bitmap iteration should terminate. 444 virtual bool do_bit(BitMap::idx_t offset) = 0; 445 }; 446 447 #endif // SHARE_UTILITIES_BITMAP_HPP 448