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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7 * published by the Free Software Foundation.
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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13 * accompanied this code).
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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
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 idx_t size() const { return _size; }
199 idx_t size_in_words() const { return calc_size_in_words(size()); }
200 idx_t size_in_bytes() const { return calc_size_in_bytes(size()); }
201
202 bool at(idx_t index) const {
203 verify_index(index);
204 return (*word_addr(index) & bit_mask(index)) != 0;
205 }
206
207 // Align bit index up or down to the next bitmap word boundary, or check
208 // alignment.
209 static idx_t word_align_up(idx_t bit) {
210 return align_up(bit, BitsPerWord);
211 }
212 static idx_t word_align_down(idx_t bit) {
213 return align_down(bit, BitsPerWord);
214 }
215 static bool is_word_aligned(idx_t bit) {
216 return word_align_up(bit) == bit;
217 }
218
219 // Set or clear the specified bit.
220 inline void set_bit(idx_t bit);
221 inline void clear_bit(idx_t bit);
222
223 // Atomically set or clear the specified bit.
224 inline bool par_set_bit(idx_t bit);
225 inline bool par_clear_bit(idx_t bit);
226
227 // Put the given value at the given offset. The parallel version
228 // will CAS the value into the bitmap and is quite a bit slower.
229 // The parallel version also returns a value indicating if the
230 // calling thread was the one that changed the value of the bit.
231 void at_put(idx_t index, bool value);
232 bool par_at_put(idx_t index, bool value);
233
234 // Update a range of bits. Ranges are half-open [beg, end).
235 void set_range (idx_t beg, idx_t end);
236 void clear_range (idx_t beg, idx_t end);
237 void set_large_range (idx_t beg, idx_t end);
238 void clear_large_range (idx_t beg, idx_t end);
239 void at_put_range(idx_t beg, idx_t end, bool value);
240 void par_at_put_range(idx_t beg, idx_t end, bool value);
241 void at_put_large_range(idx_t beg, idx_t end, bool value);
242 void par_at_put_large_range(idx_t beg, idx_t end, bool value);
243
244 // Update a range of bits, using a hint about the size. Currently only
245 // inlines the predominant case of a 1-bit range. Works best when hint is a
246 // compile-time constant.
247 void set_range(idx_t beg, idx_t end, RangeSizeHint hint);
248 void clear_range(idx_t beg, idx_t end, RangeSizeHint hint);
249 void par_set_range(idx_t beg, idx_t end, RangeSizeHint hint);
250 void par_clear_range (idx_t beg, idx_t end, RangeSizeHint hint);
251
252 // Clearing
253 void clear_large();
254 inline void clear();
255
256 // Iteration support. Returns "true" if the iteration completed, false
257 // if the iteration terminated early (because the closure "blk" returned
258 // false).
259 bool iterate(BitMapClosure* blk, idx_t leftIndex, idx_t rightIndex);
260 bool iterate(BitMapClosure* blk) {
261 // call the version that takes an interval
262 return iterate(blk, 0, size());
263 }
264
265 // Looking for 1's and 0's at indices equal to or greater than "l_index",
266 // stopping if none has been found before "r_index", and returning
267 // "r_index" (which must be at most "size") in that case.
268 idx_t get_next_one_offset (idx_t l_index, idx_t r_index) const;
269 idx_t get_next_zero_offset(idx_t l_index, idx_t r_index) const;
270
271 idx_t get_next_one_offset(idx_t offset) const {
272 return get_next_one_offset(offset, size());
273 }
274 idx_t get_next_zero_offset(idx_t offset) const {
275 return get_next_zero_offset(offset, size());
276 }
277
278 // Like "get_next_one_offset", except requires that "r_index" is
279 // aligned to bitsizeof(bm_word_t).
280 idx_t get_next_one_offset_aligned_right(idx_t l_index, idx_t r_index) const;
281
282 // Returns the number of bits set in the bitmap.
283 idx_t count_one_bits() const;
284
285 // Set operations.
286 void set_union(const BitMap& bits);
287 void set_difference(const BitMap& bits);
288 void set_intersection(const BitMap& bits);
289 // Returns true iff "this" is a superset of "bits".
290 bool contains(const BitMap& bits) const;
291 // Returns true iff "this and "bits" have a non-empty intersection.
292 bool intersects(const BitMap& bits) const;
293
294 // Returns result of whether this map changed
295 // during the operation
296 bool set_union_with_result(const BitMap& bits);
297 bool set_difference_with_result(const BitMap& bits);
298 bool set_intersection_with_result(const BitMap& bits);
299
300 void set_from(const BitMap& bits);
301
302 bool is_same(const BitMap& bits) const;
303
304 // Test if all bits are set or cleared
305 bool is_full() const;
306 bool is_empty() const;
307
308 void write_to(bm_word_t* buffer, size_t buffer_size_in_bytes) const;
309 void print_on_error(outputStream* st, const char* prefix) const;
310
311 #ifndef PRODUCT
312 public:
313 // Printing
314 void print_on(outputStream* st) const;
315 #endif
316 };
317
318 // A concrete implementation of the the "abstract" BitMap class.
319 //
320 // The BitMapView is used when the backing storage is managed externally.
321 class BitMapView : public BitMap {
322 public:
323 BitMapView() : BitMap(NULL, 0) {}
324 BitMapView(bm_word_t* map, idx_t size_in_bits) : BitMap(map, size_in_bits) {}
325 };
326
327 // A BitMap with storage in a ResourceArea.
328 class ResourceBitMap : public BitMap {
329
330 public:
331 ResourceBitMap() : BitMap(NULL, 0) {}
332 // Conditionally clears the bitmap memory.
333 ResourceBitMap(idx_t size_in_bits, bool clear = true);
334
335 // Resize the backing bitmap memory.
336 //
337 // Old bits are transfered to the new memory
338 // and the extended memory is cleared.
339 void resize(idx_t new_size_in_bits);
340
341 // Set up and clear the bitmap memory.
342 //
343 // Precondition: The bitmap was default constructed and has
344 // not yet had memory allocated via resize or initialize.
345 void initialize(idx_t size_in_bits);
346
347 // Set up and clear the bitmap memory.
348 //
349 // Can be called on previously initialized bitmaps.
350 void reinitialize(idx_t size_in_bits);
351 };
352
353 // A BitMap with storage in a specific Arena.
354 class ArenaBitMap : public BitMap {
355 public:
356 // Clears the bitmap memory.
357 ArenaBitMap(Arena* arena, idx_t size_in_bits);
358
359 private:
360 // Don't allow copy or assignment.
361 ArenaBitMap(const ArenaBitMap&);
362 ArenaBitMap& operator=(const ArenaBitMap&);
363 };
364
365 // A BitMap with storage in the CHeap.
366 class CHeapBitMap : public BitMap {
367
368 private:
369 // Don't allow copy or assignment, to prevent the
370 // allocated memory from leaking out to other instances.
371 CHeapBitMap(const CHeapBitMap&);
372 CHeapBitMap& operator=(const CHeapBitMap&);
373
374 // NMT memory type
375 MEMFLAGS _flags;
376
377 public:
378 CHeapBitMap(MEMFLAGS flags = mtInternal) : BitMap(NULL, 0), _flags(flags) {}
379 // Clears the bitmap memory.
380 CHeapBitMap(idx_t size_in_bits, MEMFLAGS flags = mtInternal, bool clear = true);
381 ~CHeapBitMap();
382
383 // Resize the backing bitmap memory.
384 //
385 // Old bits are transfered to the new memory
386 // and the extended memory is (optionally) cleared.
387 void resize(idx_t new_size_in_bits, bool clear = true);
388
389 // Set up and (optionally) clear the bitmap memory.
390 //
391 // Precondition: The bitmap was default constructed and has
392 // not yet had memory allocated via resize or initialize.
393 void initialize(idx_t size_in_bits, bool clear = true);
394
395 // Set up and (optionally) clear the bitmap memory.
396 //
397 // Can be called on previously initialized bitmaps.
398 void reinitialize(idx_t size_in_bits, bool clear = true);
399 };
400
401 // Convenience class wrapping BitMap which provides multiple bits per slot.
402 class BitMap2D {
403 public:
404 typedef BitMap::idx_t idx_t; // Type used for bit and word indices.
405 typedef BitMap::bm_word_t bm_word_t; // Element type of array that
406 // represents the bitmap.
407 private:
408 ResourceBitMap _map;
409 idx_t _bits_per_slot;
410
411 idx_t bit_index(idx_t slot_index, idx_t bit_within_slot_index) const {
412 return slot_index * _bits_per_slot + bit_within_slot_index;
413 }
414
415 void verify_bit_within_slot_index(idx_t index) const {
416 assert(index < _bits_per_slot, "bit_within_slot index out of bounds");
417 }
418
419 public:
420 // Construction. bits_per_slot must be greater than 0.
421 BitMap2D(idx_t bits_per_slot) :
422 _map(), _bits_per_slot(bits_per_slot) {}
423
424 // Allocates necessary data structure in resource area. bits_per_slot must be greater than 0.
425 BitMap2D(idx_t size_in_slots, idx_t bits_per_slot) :
426 _map(size_in_slots * bits_per_slot), _bits_per_slot(bits_per_slot) {}
427
428 idx_t size_in_bits() {
429 return _map.size();
430 }
431
432 bool is_valid_index(idx_t slot_index, idx_t bit_within_slot_index);
433 bool at(idx_t slot_index, idx_t bit_within_slot_index) const;
434 void set_bit(idx_t slot_index, idx_t bit_within_slot_index);
435 void clear_bit(idx_t slot_index, idx_t bit_within_slot_index);
436 void at_put(idx_t slot_index, idx_t bit_within_slot_index, bool value);
437 void at_put_grow(idx_t slot_index, idx_t bit_within_slot_index, bool value);
438 };
439
440 // Closure for iterating over BitMaps
441
442 class BitMapClosure {
443 public:
444 // Callback when bit in map is set. Should normally return "true";
445 // return of false indicates that the bitmap iteration should terminate.
446 virtual bool do_bit(BitMap::idx_t offset) = 0;
447 };
448
449 #endif // SHARE_UTILITIES_BITMAP_HPP