1 /*
2 * Copyright (c) 1997, 2016, 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).
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15 * You should have received a copy of the GNU General Public License version
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23 */
24
25 #ifndef SHARE_VM_UTILITIES_BITMAP_HPP
26 #define SHARE_VM_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 VALUE_OBJ_CLASS_SPEC {
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.
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 protected:
64 // Return the position of bit within the word that contains it (e.g., if
65 // bitmap words are 32 bits, return a number 0 <= n <= 31).
66 static idx_t bit_in_word(idx_t bit) { return bit & (BitsPerWord - 1); }
67
68 // Return a mask that will select the specified bit, when applied to the word
69 // containing the bit.
70 static bm_word_t bit_mask(idx_t bit) { return (bm_word_t)1 << bit_in_word(bit); }
71
72 // Return the index of the word containing the specified bit.
73 static idx_t word_index(idx_t bit) { return bit >> LogBitsPerWord; }
74
75 // Return the bit number of the first bit in the specified word.
76 static idx_t bit_index(idx_t word) { return word << LogBitsPerWord; }
77
78 // Return the array of bitmap words, or a specific word from it.
79 bm_word_t* map() { return _map; }
80 const bm_word_t* map() const { return _map; }
81 bm_word_t map(idx_t word) const { return _map[word]; }
82
83 // Return a pointer to the word containing the specified bit.
84 bm_word_t* word_addr(idx_t bit) { return map() + word_index(bit); }
85 const bm_word_t* word_addr(idx_t bit) const { return map() + word_index(bit); }
86
87 // Set a word to a specified value or to all ones; clear a word.
88 void set_word (idx_t word, bm_word_t val) { _map[word] = val; }
89 void set_word (idx_t word) { set_word(word, ~(bm_word_t)0); }
90 void clear_word(idx_t word) { _map[word] = 0; }
91
92 // Utilities for ranges of bits. Ranges are half-open [beg, end).
93
94 // Ranges within a single word.
95 bm_word_t inverted_bit_mask_for_range(idx_t beg, idx_t end) const;
96 void set_range_within_word (idx_t beg, idx_t end);
97 void clear_range_within_word (idx_t beg, idx_t end);
98 void par_put_range_within_word (idx_t beg, idx_t end, bool value);
99
100 // Ranges spanning entire words.
101 void set_range_of_words (idx_t beg, idx_t end);
102 void clear_range_of_words (idx_t beg, idx_t end);
103 void set_large_range_of_words (idx_t beg, idx_t end);
104 void clear_large_range_of_words (idx_t beg, idx_t end);
105
106 static void clear_range_of_words(bm_word_t* map, idx_t beg, idx_t end);
107
108 // The index of the first full word in a range.
109 idx_t word_index_round_up(idx_t bit) const;
110
111 // Verification.
112 void verify_index(idx_t index) const NOT_DEBUG_RETURN;
113 void verify_range(idx_t beg_index, idx_t end_index) const NOT_DEBUG_RETURN;
114
115 // Statistics.
116 static idx_t* _pop_count_table;
117 static void init_pop_count_table();
118 static idx_t num_set_bits(bm_word_t w);
119 static idx_t num_set_bits_from_table(unsigned char c);
120
121 // Allocation Helpers.
122
123 // Allocates and clears the bitmap memory.
124 template <class Allocator>
125 static bm_word_t* allocate(const Allocator&, idx_t size_in_bits);
126
127 // Reallocates and clears the new bitmap memory.
128 template <class Allocator>
129 static bm_word_t* reallocate(const Allocator&, bm_word_t* map, idx_t old_size_in_bits, idx_t new_size_in_bits);
130
131 // Free the bitmap memory.
132 template <class Allocator>
133 static void free(const Allocator&, bm_word_t* map, idx_t size_in_bits);
134
135 // Protected functions, that are used by BitMap sub-classes that support them.
136
137 // Resize the backing bitmap memory.
138 //
139 // Old bits are transfered to the new memory
140 // and the extended memory is cleared.
141 template <class Allocator>
142 void resize(const Allocator& allocator, idx_t new_size_in_bits);
143
144 // Set up and clear the bitmap memory.
145 //
146 // Precondition: The bitmap was default constructed and has
147 // not yet had memory allocated via resize or (re)initialize.
148 template <class Allocator>
149 void initialize(const Allocator& allocator, idx_t size_in_bits);
150
151 // Set up and clear the bitmap memory.
152 //
153 // Can be called on previously initialized bitmaps.
154 template <class Allocator>
155 void reinitialize(const Allocator& allocator, idx_t new_size_in_bits);
156
157 // Set the map and size.
158 void update(bm_word_t* map, idx_t size) {
159 _map = map;
160 _size = size;
161 }
162
163 // Protected constructor and destructor.
164 BitMap(bm_word_t* map, idx_t size_in_bits) : _map(map), _size(size_in_bits) {}
165 ~BitMap() {}
166
167 public:
168 // Pretouch the entire range of memory this BitMap covers.
169 void pretouch();
170
171 // Accessing
172 static idx_t calc_size_in_words(size_t size_in_bits) {
173 return word_index(size_in_bits + BitsPerWord - 1);
174 }
175
176 static idx_t calc_size_in_bytes(size_t size_in_bits) {
177 return calc_size_in_words(size_in_bits) * BytesPerWord;
178 }
179
180 idx_t size() const { return _size; }
181 idx_t size_in_words() const { return calc_size_in_words(size()); }
182 idx_t size_in_bytes() const { return calc_size_in_bytes(size()); }
183
184 bool at(idx_t index) const {
185 verify_index(index);
186 return (*word_addr(index) & bit_mask(index)) != 0;
187 }
188
189 // Align bit index up or down to the next bitmap word boundary, or check
190 // alignment.
191 static idx_t word_align_up(idx_t bit) {
192 return align_size_up(bit, BitsPerWord);
193 }
194 static idx_t word_align_down(idx_t bit) {
195 return align_size_down(bit, BitsPerWord);
196 }
197 static bool is_word_aligned(idx_t bit) {
198 return word_align_up(bit) == bit;
199 }
200
201 // Set or clear the specified bit.
202 inline void set_bit(idx_t bit);
203 inline void clear_bit(idx_t bit);
204
205 // Atomically set or clear the specified bit.
206 inline bool par_set_bit(idx_t bit);
207 inline bool par_clear_bit(idx_t bit);
208
209 // Put the given value at the given offset. The parallel version
210 // will CAS the value into the bitmap and is quite a bit slower.
211 // The parallel version also returns a value indicating if the
212 // calling thread was the one that changed the value of the bit.
213 void at_put(idx_t index, bool value);
214 bool par_at_put(idx_t index, bool value);
215
216 // Update a range of bits. Ranges are half-open [beg, end).
217 void set_range (idx_t beg, idx_t end);
218 void clear_range (idx_t beg, idx_t end);
219 void set_large_range (idx_t beg, idx_t end);
220 void clear_large_range (idx_t beg, idx_t end);
221 void at_put_range(idx_t beg, idx_t end, bool value);
222 void par_at_put_range(idx_t beg, idx_t end, bool value);
223 void at_put_large_range(idx_t beg, idx_t end, bool value);
224 void par_at_put_large_range(idx_t beg, idx_t end, bool value);
225
226 // Update a range of bits, using a hint about the size. Currently only
227 // inlines the predominant case of a 1-bit range. Works best when hint is a
228 // compile-time constant.
229 void set_range(idx_t beg, idx_t end, RangeSizeHint hint);
230 void clear_range(idx_t beg, idx_t end, RangeSizeHint hint);
231 void par_set_range(idx_t beg, idx_t end, RangeSizeHint hint);
232 void par_clear_range (idx_t beg, idx_t end, RangeSizeHint hint);
233
234 // Clearing
235 void clear_large();
236 inline void clear();
237
238 // Iteration support. Returns "true" if the iteration completed, false
239 // if the iteration terminated early (because the closure "blk" returned
240 // false).
241 bool iterate(BitMapClosure* blk, idx_t leftIndex, idx_t rightIndex);
242 bool iterate(BitMapClosure* blk) {
243 // call the version that takes an interval
244 return iterate(blk, 0, size());
245 }
246
247 // Looking for 1's and 0's at indices equal to or greater than "l_index",
248 // stopping if none has been found before "r_index", and returning
249 // "r_index" (which must be at most "size") in that case.
250 idx_t get_next_one_offset_inline (idx_t l_index, idx_t r_index) const;
251 idx_t get_next_zero_offset_inline(idx_t l_index, idx_t r_index) const;
252
253 // Like "get_next_one_offset_inline", except requires that "r_index" is
254 // aligned to bitsizeof(bm_word_t).
255 idx_t get_next_one_offset_inline_aligned_right(idx_t l_index,
256 idx_t r_index) const;
257
258 // Non-inline versionsof the above.
259 idx_t get_next_one_offset (idx_t l_index, idx_t r_index) const;
260 idx_t get_next_zero_offset(idx_t l_index, idx_t r_index) const;
261
262 idx_t get_next_one_offset(idx_t offset) const {
263 return get_next_one_offset(offset, size());
264 }
265 idx_t get_next_zero_offset(idx_t offset) const {
266 return get_next_zero_offset(offset, size());
267 }
268
269 // Returns the number of bits set in the bitmap.
270 idx_t count_one_bits() const;
271
272 // Set operations.
273 void set_union(const BitMap& bits);
274 void set_difference(const BitMap& bits);
275 void set_intersection(const BitMap& bits);
276 // Returns true iff "this" is a superset of "bits".
277 bool contains(const BitMap& bits) const;
278 // Returns true iff "this and "bits" have a non-empty intersection.
279 bool intersects(const BitMap& bits) const;
280
281 // Returns result of whether this map changed
282 // during the operation
283 bool set_union_with_result(const BitMap& bits);
284 bool set_difference_with_result(const BitMap& bits);
285 bool set_intersection_with_result(const BitMap& bits);
286
287 void set_from(const BitMap& bits);
288
289 bool is_same(const BitMap& bits) const;
290
291 // Test if all bits are set or cleared
292 bool is_full() const;
293 bool is_empty() const;
294
295 void print_on_error(outputStream* st, const char* prefix) const;
296
297 #ifndef PRODUCT
298 public:
299 // Printing
300 void print_on(outputStream* st) const;
301 #endif
302 };
303
304 // A concrete implementation of the the "abstract" BitMap class.
305 //
306 // The BitMapView is used when the backing storage is managed externally.
307 class BitMapView : public BitMap {
308 public:
309 BitMapView() : BitMap(NULL, 0) {}
310 BitMapView(bm_word_t* map, idx_t size_in_bits) : BitMap(map, size_in_bits) {}
311 };
312
313 // A BitMap with storage in a ResourceArea.
314 class ResourceBitMap : public BitMap {
315
316 public:
317 ResourceBitMap() : BitMap(NULL, 0) {}
318 // Clears the bitmap memory.
319 ResourceBitMap(idx_t size_in_bits);
320
321 // Resize the backing bitmap memory.
322 //
323 // Old bits are transfered to the new memory
324 // and the extended memory is cleared.
325 void resize(idx_t new_size_in_bits);
326
327 // Set up and clear the bitmap memory.
328 //
329 // Precondition: The bitmap was default constructed and has
330 // not yet had memory allocated via resize or initialize.
331 void initialize(idx_t size_in_bits);
332
333 // Set up and clear the bitmap memory.
334 //
335 // Can be called on previously initialized bitmaps.
336 void reinitialize(idx_t size_in_bits);
337 };
338
339 // A BitMap with storage in a specific Arena.
340 class ArenaBitMap : public BitMap {
341 public:
342 // Clears the bitmap memory.
343 ArenaBitMap(Arena* arena, idx_t size_in_bits);
344
345 private:
346 // Don't allow copy or assignment.
347 ArenaBitMap(const ArenaBitMap&);
348 ArenaBitMap& operator=(const ArenaBitMap&);
349 };
350
351 // A BitMap with storage in the CHeap.
352 class CHeapBitMap : public BitMap {
353
354 private:
355 // Don't allow copy or assignment, to prevent the
356 // allocated memory from leaking out to other instances.
357 CHeapBitMap(const CHeapBitMap&);
358 CHeapBitMap& operator=(const CHeapBitMap&);
359
360 public:
361 CHeapBitMap() : BitMap(NULL, 0) {}
362 // Clears the bitmap memory.
363 CHeapBitMap(idx_t size_in_bits);
364 ~CHeapBitMap();
365
366 // Resize the backing bitmap memory.
367 //
368 // Old bits are transfered to the new memory
369 // and the extended memory is cleared.
370 void resize(idx_t new_size_in_bits);
371
372 // Set up and clear the bitmap memory.
373 //
374 // Precondition: The bitmap was default constructed and has
375 // not yet had memory allocated via resize or initialize.
376 void initialize(idx_t size_in_bits);
377
378 // Set up and clear the bitmap memory.
379 //
380 // Can be called on previously initialized bitmaps.
381 void reinitialize(idx_t size_in_bits);
382 };
383
384 // Convenience class wrapping BitMap which provides multiple bits per slot.
385 class BitMap2D VALUE_OBJ_CLASS_SPEC {
386 public:
387 typedef BitMap::idx_t idx_t; // Type used for bit and word indices.
388 typedef BitMap::bm_word_t bm_word_t; // Element type of array that
389 // represents the bitmap.
390 private:
391 ResourceBitMap _map;
392 idx_t _bits_per_slot;
393
394 idx_t bit_index(idx_t slot_index, idx_t bit_within_slot_index) const {
395 return slot_index * _bits_per_slot + bit_within_slot_index;
396 }
397
398 void verify_bit_within_slot_index(idx_t index) const {
399 assert(index < _bits_per_slot, "bit_within_slot index out of bounds");
400 }
401
402 public:
403 // Construction. bits_per_slot must be greater than 0.
404 BitMap2D(idx_t bits_per_slot) :
405 _map(), _bits_per_slot(bits_per_slot) {}
406
407 // Allocates necessary data structure in resource area. bits_per_slot must be greater than 0.
408 BitMap2D(idx_t size_in_slots, idx_t bits_per_slot) :
409 _map(size_in_slots * bits_per_slot), _bits_per_slot(bits_per_slot) {}
410
411 idx_t size_in_bits() {
412 return _map.size();
413 }
414
415 // Returns number of full slots that have been allocated
416 idx_t size_in_slots() {
417 // Round down
418 return _map.size() / _bits_per_slot;
419 }
420
421 bool is_valid_index(idx_t slot_index, idx_t bit_within_slot_index);
422 bool at(idx_t slot_index, idx_t bit_within_slot_index) const;
423 void set_bit(idx_t slot_index, idx_t bit_within_slot_index);
424 void clear_bit(idx_t slot_index, idx_t bit_within_slot_index);
425 void at_put(idx_t slot_index, idx_t bit_within_slot_index, bool value);
426 void at_put_grow(idx_t slot_index, idx_t bit_within_slot_index, bool value);
427 };
428
429 // Closure for iterating over BitMaps
430
431 class BitMapClosure VALUE_OBJ_CLASS_SPEC {
432 public:
433 // Callback when bit in map is set. Should normally return "true";
434 // return of false indicates that the bitmap iteration should terminate.
435 virtual bool do_bit(BitMap::idx_t offset) = 0;
436 };
437
438 #endif // SHARE_VM_UTILITIES_BITMAP_HPP