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.
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5 * This code is free software; you can redistribute it and/or modify it
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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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
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 // Helper for get_next_{zero,one}_bit variants.
65 // - flip designates whether searching for 1s or 0s. Must be one of
66 // find_{zeros,ones}_flip.
67 // - aligned_right is true if r_index is a priori on a bm_word_t boundary.
68 template<bm_word_t flip, bool aligned_right>
69 inline idx_t get_next_bit_impl(idx_t l_index, idx_t r_index) const;
70
71 // Values for get_next_bit_impl flip parameter.
72 static const bm_word_t find_ones_flip = 0;
73 static const bm_word_t find_zeros_flip = ~(bm_word_t)0;
74
75 // Threshold for performing small range operation, even when large range
76 // operation was requested. Measured in words.
77 static const size_t small_range_words = 32;
78
79 protected:
80 // Return the position of bit within the word that contains it (e.g., if
81 // bitmap words are 32 bits, return a number 0 <= n <= 31).
82 static idx_t bit_in_word(idx_t bit) { return bit & (BitsPerWord - 1); }
83
84 // Return a mask that will select the specified bit, when applied to the word
85 // containing the bit.
86 static bm_word_t bit_mask(idx_t bit) { return (bm_word_t)1 << bit_in_word(bit); }
87
88 // Return the index of the word containing the specified bit.
89 static idx_t word_index(idx_t bit) { return bit >> LogBitsPerWord; }
90
91 // Return the bit number of the first bit in the specified word.
92 static idx_t bit_index(idx_t word) { return word << LogBitsPerWord; }
93
94 // Return the array of bitmap words, or a specific word from it.
95 bm_word_t* map() { return _map; }
96 const bm_word_t* map() const { return _map; }
97 bm_word_t map(idx_t word) const { return _map[word]; }
98
99 // Return a pointer to the word containing the specified bit.
100 bm_word_t* word_addr(idx_t bit) { return map() + word_index(bit); }
101 const bm_word_t* word_addr(idx_t bit) const { return map() + word_index(bit); }
102
103 // Set a word to a specified value or to all ones; clear a word.
104 void set_word (idx_t word, bm_word_t val) { _map[word] = val; }
105 void set_word (idx_t word) { set_word(word, ~(bm_word_t)0); }
106 void clear_word(idx_t word) { _map[word] = 0; }
107
108 // Utilities for ranges of bits. Ranges are half-open [beg, end).
109
110 // Ranges within a single word.
111 bm_word_t inverted_bit_mask_for_range(idx_t beg, idx_t end) const;
112 void set_range_within_word (idx_t beg, idx_t end);
113 void clear_range_within_word (idx_t beg, idx_t end);
114 void par_put_range_within_word (idx_t beg, idx_t end, bool value);
115
116 // Ranges spanning entire words.
117 void set_range_of_words (idx_t beg, idx_t end);
118 void clear_range_of_words (idx_t beg, idx_t end);
119 void set_large_range_of_words (idx_t beg, idx_t end);
120 void clear_large_range_of_words (idx_t beg, idx_t end);
121
122 static void clear_range_of_words(bm_word_t* map, idx_t beg, idx_t end);
123
124 static bool is_small_range_of_words(idx_t beg_full_word, idx_t end_full_word);
125
126 // The index of the first full word in a range.
127 idx_t word_index_round_up(idx_t bit) const;
128
129 // Verification.
130 void verify_index(idx_t index) const NOT_DEBUG_RETURN;
131 void verify_range(idx_t beg_index, idx_t end_index) const NOT_DEBUG_RETURN;
132
133 // Statistics.
134 static const idx_t* _pop_count_table;
135 static void init_pop_count_table();
136 static idx_t num_set_bits(bm_word_t w);
137 static idx_t num_set_bits_from_table(unsigned char c);
138
139 // Allocation Helpers.
140
141 // Allocates and clears the bitmap memory.
142 template <class Allocator>
143 static bm_word_t* allocate(const Allocator&, idx_t size_in_bits, bool clear = true);
144
145 // Reallocates and clears the new bitmap memory.
146 template <class Allocator>
147 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);
148
149 // Free the bitmap memory.
150 template <class Allocator>
151 static void free(const Allocator&, bm_word_t* map, idx_t size_in_bits);
152
153 // Protected functions, that are used by BitMap sub-classes that support them.
154
155 // Resize the backing bitmap memory.
156 //
157 // Old bits are transfered to the new memory
158 // and the extended memory is cleared.
159 template <class Allocator>
160 void resize(const Allocator& allocator, idx_t new_size_in_bits, bool clear);
161
162 // Set up and clear the bitmap memory.
163 //
164 // Precondition: The bitmap was default constructed and has
165 // not yet had memory allocated via resize or (re)initialize.
166 template <class Allocator>
167 void initialize(const Allocator& allocator, idx_t size_in_bits, bool clear);
168
169 // Set up and clear the bitmap memory.
170 //
171 // Can be called on previously initialized bitmaps.
172 template <class Allocator>
173 void reinitialize(const Allocator& allocator, idx_t new_size_in_bits, bool clear);
174
175 // Set the map and size.
176 void update(bm_word_t* map, idx_t size) {
177 _map = map;
178 _size = size;
179 }
180
181 // Protected constructor and destructor.
182 BitMap(bm_word_t* map, idx_t size_in_bits) : _map(map), _size(size_in_bits) {}
183 ~BitMap() {}
184
185 public:
186 // Pretouch the entire range of memory this BitMap covers.
187 void pretouch();
188
189 // Accessing
190 static idx_t calc_size_in_words(size_t size_in_bits) {
191 return word_index(size_in_bits + BitsPerWord - 1);
192 }
193
194 static idx_t calc_size_in_bytes(size_t size_in_bits) {
195 return calc_size_in_words(size_in_bits) * BytesPerWord;
196 }
197
198 // Size, in number of bits, of this map.
199 idx_t size() const { return _size; }
200 idx_t size_in_words() const { return calc_size_in_words(size()); }
201 idx_t size_in_bytes() const { return calc_size_in_bytes(size()); }
202
203 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.
210 static idx_t word_align_up(idx_t bit) {
211 return align_up(bit, BitsPerWord);
212 }
213 static idx_t word_align_down(idx_t bit) {
214 return align_down(bit, BitsPerWord);
215 }
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 [leftIndex, rightIndex). 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) const;
261 bool iterate(BitMapClosure* blk) const {
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
272 idx_t get_next_one_offset(idx_t offset) const {
273 return get_next_one_offset(offset, size());
274 }
275 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 between [l_index, r_index) in the bitmap.
284 idx_t count_one_bits(idx_t l_index, idx_t r_index) const;
285
286 // Returns the number of bits set in the bitmap.
287 idx_t count_one_bits() const;
288
289 // Set operations.
290 void set_union(const BitMap& bits);
291 void set_difference(const BitMap& bits);
292 void set_intersection(const BitMap& bits);
293 // Returns true iff "this" is a superset of "bits".
294 bool contains(const BitMap& bits) const;
295 // Returns true iff "this and "bits" have a non-empty intersection.
296 bool intersects(const BitMap& bits) const;
297
298 // Returns result of whether this map changed
299 // during the operation
300 bool set_union_with_result(const BitMap& bits);
301 bool set_difference_with_result(const BitMap& bits);
302 bool set_intersection_with_result(const BitMap& bits);
303
304 void set_from(const BitMap& bits);
305
306 bool is_same(const BitMap& bits) const;
307
308 // Test if all bits are set or cleared
309 bool is_full() const;
310 bool is_empty() const;
311
312 void write_to(bm_word_t* buffer, size_t buffer_size_in_bytes) const;
313 void print_on_error(outputStream* st, const char* prefix) const;
314
315 #ifndef PRODUCT
316 public:
317 // Printing
318 void print_on(outputStream* st) const;
319 #endif
320 };
321
322 // A concrete implementation of the the "abstract" BitMap class.
323 //
324 // The BitMapView is used when the backing storage is managed externally.
325 class BitMapView : public BitMap {
326 public:
327 BitMapView() : BitMap(NULL, 0) {}
328 BitMapView(bm_word_t* map, idx_t size_in_bits) : BitMap(map, size_in_bits) {}
329 };
330
331 // A BitMap with storage in a ResourceArea.
332 class ResourceBitMap : public BitMap {
333
334 public:
335 ResourceBitMap() : BitMap(NULL, 0) {}
336 // Conditionally clears the bitmap memory.
337 ResourceBitMap(idx_t size_in_bits, bool clear = true);
338
339 // Resize the backing bitmap memory.
340 //
341 // Old bits are transfered to the new memory
342 // and the extended memory is cleared.
343 void resize(idx_t new_size_in_bits);
344
345 // Set up and clear the bitmap memory.
346 //
347 // Precondition: The bitmap was default constructed and has
348 // not yet had memory allocated via resize or initialize.
349 void initialize(idx_t size_in_bits);
350
351 // Set up and clear the bitmap memory.
352 //
353 // Can be called on previously initialized bitmaps.
354 void reinitialize(idx_t size_in_bits);
355 };
356
357 // A BitMap with storage in a specific Arena.
358 class ArenaBitMap : public BitMap {
359 public:
360 // Clears the bitmap memory.
361 ArenaBitMap(Arena* arena, idx_t size_in_bits);
362
363 private:
364 // Don't allow copy or assignment.
365 ArenaBitMap(const ArenaBitMap&);
366 ArenaBitMap& operator=(const ArenaBitMap&);
367 };
368
369 // A BitMap with storage in the CHeap.
370 class CHeapBitMap : public BitMap {
371
372 private:
373 // Don't allow copy or assignment, to prevent the
374 // allocated memory from leaking out to other instances.
375 CHeapBitMap(const CHeapBitMap&);
376 CHeapBitMap& operator=(const CHeapBitMap&);
377
378 // NMT memory type
379 MEMFLAGS _flags;
380
381 public:
382 CHeapBitMap(MEMFLAGS flags = mtInternal) : BitMap(NULL, 0), _flags(flags) {}
383 // Clears the bitmap memory.
384 CHeapBitMap(idx_t size_in_bits, MEMFLAGS flags = mtInternal, bool clear = true);
385 ~CHeapBitMap();
386
387 // Resize the backing bitmap memory.
388 //
389 // Old bits are transfered to the new memory
390 // and the extended memory is (optionally) cleared.
391 void resize(idx_t new_size_in_bits, bool clear = true);
392
393 // Set up and (optionally) clear the bitmap memory.
394 //
395 // Precondition: The bitmap was default constructed and has
396 // not yet had memory allocated via resize or initialize.
397 void initialize(idx_t size_in_bits, bool clear = true);
398
399 // Set up and (optionally) clear the bitmap memory.
400 //
401 // Can be called on previously initialized bitmaps.
402 void reinitialize(idx_t size_in_bits, bool clear = true);
403 };
404
405 // Convenience class wrapping BitMap which provides multiple bits per slot.
406 class BitMap2D {
407 public:
408 typedef BitMap::idx_t idx_t; // Type used for bit and word indices.
409 typedef BitMap::bm_word_t bm_word_t; // Element type of array that
410 // represents the bitmap.
411 private:
412 ResourceBitMap _map;
413 idx_t _bits_per_slot;
414
415 idx_t bit_index(idx_t slot_index, idx_t bit_within_slot_index) const {
416 return slot_index * _bits_per_slot + bit_within_slot_index;
417 }
418
419 void verify_bit_within_slot_index(idx_t index) const {
420 assert(index < _bits_per_slot, "bit_within_slot index out of bounds");
421 }
422
423 public:
424 // Construction. bits_per_slot must be greater than 0.
425 BitMap2D(idx_t bits_per_slot) :
426 _map(), _bits_per_slot(bits_per_slot) {}
427
428 // Allocates necessary data structure in resource area. bits_per_slot must be greater than 0.
429 BitMap2D(idx_t size_in_slots, idx_t bits_per_slot) :
430 _map(size_in_slots * bits_per_slot), _bits_per_slot(bits_per_slot) {}
431
432 idx_t size_in_bits() {
433 return _map.size();
434 }
435
436 bool is_valid_index(idx_t slot_index, idx_t bit_within_slot_index);
437 bool at(idx_t slot_index, idx_t bit_within_slot_index) const;
438 void set_bit(idx_t slot_index, idx_t bit_within_slot_index);
439 void clear_bit(idx_t slot_index, idx_t bit_within_slot_index);
440 void at_put(idx_t slot_index, idx_t bit_within_slot_index, bool value);
441 void at_put_grow(idx_t slot_index, idx_t bit_within_slot_index, bool value);
442 };
443
444 // Closure for iterating over BitMaps
445
446 class BitMapClosure {
447 public:
448 // Callback when bit in map is set. Should normally return "true";
449 // return of false indicates that the bitmap iteration should terminate.
450 virtual bool do_bit(BitMap::idx_t offset) = 0;
451 };
452
453 #endif // SHARE_UTILITIES_BITMAP_HPP