1 /*
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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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24
25 #ifndef SHARE_UTILITIES_BITMAP_HPP
26 #define SHARE_UTILITIES_BITMAP_HPP
27
28 #include "memory/allocation.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. BitsPerWord bits per element.
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 // Limit max_size_in_bits so roundup in calc_size_in_words can't overflow.
64 static idx_t max_size_in_words() { return word_index(~idx_t(0)); }
65 static idx_t max_size_in_bits() { return max_size_in_words() * BitsPerWord; }
66
67 // Helper for get_next_{zero,one}_bit variants.
68 // - flip designates whether searching for 1s or 0s. Must be one of
69 // find_{zeros,ones}_flip.
70 // - aligned_right is true if r_index is a priori on a bm_word_t boundary.
71 template<bm_word_t flip, bool aligned_right>
72 inline idx_t get_next_bit_impl(idx_t l_index, idx_t r_index) const;
73
74 // Values for get_next_bit_impl flip parameter.
75 static const bm_word_t find_ones_flip = 0;
76 static const bm_word_t find_zeros_flip = ~(bm_word_t)0;
77
78 // Threshold for performing small range operation, even when large range
79 // operation was requested. Measured in words.
80 static const size_t small_range_words = 32;
81
82 protected:
83 // Return the position of bit within the word that contains it (e.g., if
84 // bitmap words are 32 bits, return a number 0 <= n <= 31).
85 static idx_t bit_in_word(idx_t bit) { return bit & (BitsPerWord - 1); }
86
87 // Return a mask that will select the specified bit, when applied to the word
88 // containing the bit.
89 static bm_word_t bit_mask(idx_t bit) { return (bm_word_t)1 << bit_in_word(bit); }
90
91 // Return the index of the word containing the specified bit.
92 static idx_t word_index(idx_t bit) { return bit >> LogBitsPerWord; }
93
94 // Return the bit number of the first bit in the specified word.
95 static idx_t bit_index(idx_t word) { return word << LogBitsPerWord; }
96
97 // Return the array of bitmap words, or a specific word from it.
98 bm_word_t* map() { return _map; }
99 const bm_word_t* map() const { return _map; }
100 bm_word_t map(idx_t word) const { return _map[word]; }
101
102 // Return a pointer to the word containing the specified bit.
103 bm_word_t* word_addr(idx_t bit) { return map() + word_index(bit); }
104 const bm_word_t* word_addr(idx_t bit) const { return map() + word_index(bit); }
105
106 // Set a word to a specified value or to all ones; clear a word.
107 void set_word (idx_t word, bm_word_t val) { _map[word] = val; }
108 void set_word (idx_t word) { set_word(word, ~(bm_word_t)0); }
109 void clear_word(idx_t word) { _map[word] = 0; }
110
111 // Utilities for ranges of bits. Ranges are half-open [beg, end).
112
113 // Ranges within a single word.
114 bm_word_t inverted_bit_mask_for_range(idx_t beg, idx_t end) const;
115 void set_range_within_word (idx_t beg, idx_t end);
116 void clear_range_within_word (idx_t beg, idx_t end);
117 void par_put_range_within_word (idx_t beg, idx_t end, bool value);
118
119 // Ranges spanning entire words.
120 void set_range_of_words (idx_t beg, idx_t end);
121 void clear_range_of_words (idx_t beg, idx_t end);
122 void set_large_range_of_words (idx_t beg, idx_t end);
123 void clear_large_range_of_words (idx_t beg, idx_t end);
124
125 static void clear_range_of_words(bm_word_t* map, idx_t beg, idx_t end);
126
127 static bool is_small_range_of_words(idx_t beg_full_word, idx_t end_full_word);
128
129 // The index of the first full word in a range.
130 idx_t word_index_round_up(idx_t bit) const;
131
132 // Verification.
133 static void verify_max_size_limited(idx_t bit) NOT_DEBUG_RETURN;
134 void verify_index(idx_t index) const NOT_DEBUG_RETURN;
135 void verify_range(idx_t beg_index, idx_t end_index) const NOT_DEBUG_RETURN;
136
137 // Statistics.
138 static const idx_t* _pop_count_table;
139 static void init_pop_count_table();
140 static idx_t num_set_bits(bm_word_t w);
141 static idx_t num_set_bits_from_table(unsigned char c);
142
143 // Allocation Helpers.
144
145 // Allocates and clears the bitmap memory.
146 template <class Allocator>
147 static bm_word_t* allocate(const Allocator&, idx_t size_in_bits, bool clear = true);
148
149 // Reallocates and clears the new bitmap memory.
150 template <class Allocator>
151 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);
152
153 // Free the bitmap memory.
154 template <class Allocator>
155 static void free(const Allocator&, bm_word_t* map, idx_t size_in_bits);
156
157 // Protected functions, that are used by BitMap sub-classes that support them.
158
159 // Resize the backing bitmap memory.
160 //
161 // Old bits are transfered to the new memory
162 // and the extended memory is cleared.
163 template <class Allocator>
164 void resize(const Allocator& allocator, idx_t new_size_in_bits, bool clear);
165
166 // Set up and clear the bitmap memory.
167 //
168 // Precondition: The bitmap was default constructed and has
169 // not yet had memory allocated via resize or (re)initialize.
170 template <class Allocator>
171 void initialize(const Allocator& allocator, idx_t size_in_bits, bool clear);
172
173 // Set up and clear the bitmap memory.
174 //
175 // Can be called on previously initialized bitmaps.
176 template <class Allocator>
177 void reinitialize(const Allocator& allocator, idx_t new_size_in_bits, bool clear);
178
179 // Set the map and size.
180 void update(bm_word_t* map, idx_t size) {
181 _map = map;
182 _size = size;
183 }
184
185 // Protected constructor and destructor.
186 BitMap(bm_word_t* map, idx_t size_in_bits) : _map(map), _size(size_in_bits) {}
187 ~BitMap() {}
188
189 public:
190 // Pretouch the entire range of memory this BitMap covers.
191 void pretouch();
192
193 static idx_t calc_size_in_words(idx_t size_in_bits) {
194 verify_max_size_limited(size_in_bits);
195 return word_index(size_in_bits + (BitsPerWord - 1));
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 size_in_words() * BytesPerWord; }
201
202 bool at(idx_t index) const {
203 verify_index(index);
204 return (*word_addr(index) & bit_mask(index)) != 0;
205 }
206
207 // Set or clear the specified bit.
208 inline void set_bit(idx_t bit);
209 inline void clear_bit(idx_t bit);
210
211 // Atomically set or clear the specified bit.
212 inline bool par_set_bit(idx_t bit);
213 inline bool par_clear_bit(idx_t bit);
214
215 // Put the given value at the given offset. The parallel version
216 // will CAS the value into the bitmap and is quite a bit slower.
217 // The parallel version also returns a value indicating if the
218 // calling thread was the one that changed the value of the bit.
219 void at_put(idx_t index, bool value);
220 bool par_at_put(idx_t index, bool value);
221
222 // Update a range of bits. Ranges are half-open [beg, end).
223 void set_range (idx_t beg, idx_t end);
224 void clear_range (idx_t beg, idx_t end);
225 void set_large_range (idx_t beg, idx_t end);
226 void clear_large_range (idx_t beg, idx_t end);
227 void at_put_range(idx_t beg, idx_t end, bool value);
228 void par_at_put_range(idx_t beg, idx_t end, bool value);
229 void at_put_large_range(idx_t beg, idx_t end, bool value);
230 void par_at_put_large_range(idx_t beg, idx_t end, bool value);
231
232 // Update a range of bits, using a hint about the size. Currently only
233 // inlines the predominant case of a 1-bit range. Works best when hint is a
234 // compile-time constant.
235 void set_range(idx_t beg, idx_t end, RangeSizeHint hint);
236 void clear_range(idx_t beg, idx_t end, RangeSizeHint hint);
237 void par_set_range(idx_t beg, idx_t end, RangeSizeHint hint);
238 void par_clear_range (idx_t beg, idx_t end, RangeSizeHint hint);
239
240 // Clearing
241 void clear_large();
242 inline void clear();
243
244 // Iteration support. Returns "true" if the iteration completed, false
245 // if the iteration terminated early (because the closure "blk" returned
246 // false).
247 bool iterate(BitMapClosure* blk, idx_t leftIndex, idx_t rightIndex);
248 bool iterate(BitMapClosure* blk) {
249 // call the version that takes an interval
250 return iterate(blk, 0, size());
251 }
252
253 // Looking for 1's and 0's at indices equal to or greater than "l_index",
254 // stopping if none has been found before "r_index", and returning
255 // "r_index" (which must be at most "size") in that case.
256 idx_t get_next_one_offset (idx_t l_index, idx_t r_index) const;
257 idx_t get_next_zero_offset(idx_t l_index, idx_t r_index) const;
258
259 idx_t get_next_one_offset(idx_t offset) const {
260 return get_next_one_offset(offset, size());
261 }
262 idx_t get_next_zero_offset(idx_t offset) const {
263 return get_next_zero_offset(offset, size());
264 }
265
266 // Like "get_next_one_offset", except requires that "r_index" is
267 // aligned to bitsizeof(bm_word_t).
268 idx_t get_next_one_offset_aligned_right(idx_t l_index, idx_t r_index) const;
269
270 // Returns the number of bits set in the bitmap.
271 idx_t count_one_bits() const;
272
273 // Set operations.
274 void set_union(const BitMap& bits);
275 void set_difference(const BitMap& bits);
276 void set_intersection(const BitMap& bits);
277 // Returns true iff "this" is a superset of "bits".
278 bool contains(const BitMap& bits) const;
279 // Returns true iff "this and "bits" have a non-empty intersection.
280 bool intersects(const BitMap& bits) const;
281
282 // Returns result of whether this map changed
283 // during the operation
284 bool set_union_with_result(const BitMap& bits);
285 bool set_difference_with_result(const BitMap& bits);
286 bool set_intersection_with_result(const BitMap& bits);
287
288 void set_from(const BitMap& bits);
289
290 bool is_same(const BitMap& bits) const;
291
292 // Test if all bits are set or cleared
293 bool is_full() const;
294 bool is_empty() const;
295
296 void write_to(bm_word_t* buffer, size_t buffer_size_in_bytes) const;
297 void print_on_error(outputStream* st, const char* prefix) const;
298
299 #ifndef PRODUCT
300 public:
301 // Printing
302 void print_on(outputStream* st) const;
303 #endif
304 };
305
306 // A concrete implementation of the the "abstract" BitMap class.
307 //
308 // The BitMapView is used when the backing storage is managed externally.
309 class BitMapView : public BitMap {
310 public:
311 BitMapView() : BitMap(NULL, 0) {}
312 BitMapView(bm_word_t* map, idx_t size_in_bits) : BitMap(map, size_in_bits) {}
313 };
314
315 // A BitMap with storage in a ResourceArea.
316 class ResourceBitMap : public BitMap {
317
318 public:
319 ResourceBitMap() : BitMap(NULL, 0) {}
320 // Clears the bitmap memory.
321 ResourceBitMap(idx_t size_in_bits);
322
323 // Resize the backing bitmap memory.
324 //
325 // Old bits are transfered to the new memory
326 // and the extended memory is cleared.
327 void resize(idx_t new_size_in_bits);
328
329 // Set up and clear the bitmap memory.
330 //
331 // Precondition: The bitmap was default constructed and has
332 // not yet had memory allocated via resize or initialize.
333 void initialize(idx_t size_in_bits);
334
335 // Set up and clear the bitmap memory.
336 //
337 // Can be called on previously initialized bitmaps.
338 void reinitialize(idx_t size_in_bits);
339 };
340
341 // A BitMap with storage in a specific Arena.
342 class ArenaBitMap : public BitMap {
343 public:
344 // Clears the bitmap memory.
345 ArenaBitMap(Arena* arena, idx_t size_in_bits);
346
347 private:
348 // Don't allow copy or assignment.
349 ArenaBitMap(const ArenaBitMap&);
350 ArenaBitMap& operator=(const ArenaBitMap&);
351 };
352
353 // A BitMap with storage in the CHeap.
354 class CHeapBitMap : public BitMap {
355
356 private:
357 // Don't allow copy or assignment, to prevent the
358 // allocated memory from leaking out to other instances.
359 CHeapBitMap(const CHeapBitMap&);
360 CHeapBitMap& operator=(const CHeapBitMap&);
361
362 // NMT memory type
363 MEMFLAGS _flags;
364
365 public:
366 CHeapBitMap(MEMFLAGS flags = mtInternal) : BitMap(NULL, 0), _flags(flags) {}
367 // Clears the bitmap memory.
368 CHeapBitMap(idx_t size_in_bits, MEMFLAGS flags = mtInternal, bool clear = true);
369 ~CHeapBitMap();
370
371 // Resize the backing bitmap memory.
372 //
373 // Old bits are transfered to the new memory
374 // and the extended memory is cleared.
375 void resize(idx_t new_size_in_bits, bool clear = true);
376
377 // Set up and clear the bitmap memory.
378 //
379 // Precondition: The bitmap was default constructed and has
380 // not yet had memory allocated via resize or initialize.
381 void initialize(idx_t size_in_bits, bool clear = true);
382
383 // Set up and clear the bitmap memory.
384 //
385 // Can be called on previously initialized bitmaps.
386 void reinitialize(idx_t size_in_bits, bool clear = true);
387 };
388
389 // Convenience class wrapping BitMap which provides multiple bits per slot.
390 class BitMap2D {
391 public:
392 typedef BitMap::idx_t idx_t; // Type used for bit and word indices.
393 typedef BitMap::bm_word_t bm_word_t; // Element type of array that
394 // represents the bitmap.
395 private:
396 ResourceBitMap _map;
397 idx_t _bits_per_slot;
398
399 idx_t bit_index(idx_t slot_index, idx_t bit_within_slot_index) const {
400 return slot_index * _bits_per_slot + bit_within_slot_index;
401 }
402
403 void verify_bit_within_slot_index(idx_t index) const {
404 assert(index < _bits_per_slot, "bit_within_slot index out of bounds");
405 }
406
407 public:
408 // Construction. bits_per_slot must be greater than 0.
409 BitMap2D(idx_t bits_per_slot) :
410 _map(), _bits_per_slot(bits_per_slot) {}
411
412 // Allocates necessary data structure in resource area. bits_per_slot must be greater than 0.
413 BitMap2D(idx_t size_in_slots, idx_t bits_per_slot) :
414 _map(size_in_slots * bits_per_slot), _bits_per_slot(bits_per_slot) {}
415
416 idx_t size_in_bits() {
417 return _map.size();
418 }
419
420 bool is_valid_index(idx_t slot_index, idx_t bit_within_slot_index);
421 bool at(idx_t slot_index, idx_t bit_within_slot_index) const;
422 void set_bit(idx_t slot_index, idx_t bit_within_slot_index);
423 void clear_bit(idx_t slot_index, idx_t bit_within_slot_index);
424 void at_put(idx_t slot_index, idx_t bit_within_slot_index, bool value);
425 void at_put_grow(idx_t slot_index, idx_t bit_within_slot_index, bool value);
426 };
427
428 // Closure for iterating over BitMaps
429
430 class BitMapClosure {
431 public:
432 // Callback when bit in map is set. Should normally return "true";
433 // return of false indicates that the bitmap iteration should terminate.
434 virtual bool do_bit(BitMap::idx_t offset) = 0;
435 };
436
437 #endif // SHARE_UTILITIES_BITMAP_HPP