1/* Simple bitmaps.
2 Copyright (C) 1999-2017 Free Software Foundation, Inc.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify it under
7the terms of the GNU General Public License as published by the Free
8Software Foundation; either version 3, or (at your option) any later
9version.
10
11GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12WARRANTY; without even the implied warranty of MERCHANTABILITY or
13FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14for more details.
15
16You should have received a copy of the GNU General Public License
17along with GCC; see the file COPYING3. If not see
18<http://www.gnu.org/licenses/>. */
19
20#ifndef GCC_SBITMAP_H
21#define GCC_SBITMAP_H
22
23/* Implementation of sets using simple bitmap vectors.
24
25 This set representation is suitable for non-sparse sets with a known
26 (a priori) universe. The set is represented as a simple array of the
27 host's fastest unsigned integer. For a given member I in the set:
28 - the element for I will be at sbitmap[I / (bits per element)]
29 - the position for I within element is I % (bits per element)
30
31 This representation is very space-efficient for large non-sparse sets
32 with random access patterns.
33
34 The following operations can be performed in O(1) time:
35
36 * set_size : SBITMAP_SIZE
37 * member_p : bitmap_bit_p
38 * add_member : bitmap_set_bit
39 * remove_member : bitmap_clear_bit
40
41 Most other operations on this set representation are O(U) where U is
42 the size of the set universe:
43
44 * clear : bitmap_clear
45 * choose_one : bitmap_first_set_bit /
46 bitmap_last_set_bit
47 * forall : EXECUTE_IF_SET_IN_BITMAP
48 * set_copy : bitmap_copy
49 * set_intersection : bitmap_and
50 * set_union : bitmap_ior
51 * set_difference : bitmap_and_compl
52 * set_disjuction : (not implemented)
53 * set_compare : bitmap_equal_p
54 * bit_in_range_p : bitmap_bit_in_range_p
55
56 Some operations on 3 sets that occur frequently in data flow problems
57 are also implemented:
58
59 * A | (B & C) : bitmap_or_and
60 * A | (B & ~C) : bitmap_ior_and_compl
61 * A & (B | C) : bitmap_and_or
62
63 Most of the set functions have two variants: One that returns non-zero
64 if members were added or removed from the target set, and one that just
65 performs the operation without feedback. The former operations are a
66 bit more expensive but the result can often be used to avoid iterations
67 on other sets.
68
69 Allocating a bitmap is done with sbitmap_alloc, and resizing is
70 performed with sbitmap_resize.
71
72 The storage requirements for simple bitmap sets is O(U) where U is the
73 size of the set universe (colloquially the number of bits in the bitmap).
74
75 This set representation works well for relatively small data flow problems
76 (there are special routines for that, see sbitmap_vector_*). The set
77 operations can be vectorized and there is almost no computating overhead,
78 so that even sparse simple bitmap sets outperform dedicated sparse set
79 representations like linked-list bitmaps. For larger problems, the size
80 overhead of simple bitmap sets gets too high and other set representations
81 have to be used. */
82
83#define SBITMAP_ELT_BITS (HOST_BITS_PER_WIDEST_FAST_INT * 1u)
84#define SBITMAP_ELT_TYPE unsigned HOST_WIDEST_FAST_INT
85
86struct simple_bitmap_def
87{
88 unsigned int n_bits; /* Number of bits. */
89 unsigned int size; /* Size in elements. */
90 SBITMAP_ELT_TYPE elms[1]; /* The elements. */
91};
92
93/* Return the set size needed for N elements. */
94#define SBITMAP_SET_SIZE(N) (((N) + SBITMAP_ELT_BITS - 1) / SBITMAP_ELT_BITS)
95
96/* Return the number of bits in BITMAP. */
97#define SBITMAP_SIZE(BITMAP) ((BITMAP)->n_bits)
98
99/* Verify that access at INDEX in bitmap MAP is valid. */
100
101static inline void
102bitmap_check_index (const_sbitmap map, int index)
103{
104 gcc_checking_assert (index >= 0);
105 gcc_checking_assert ((unsigned int)index < map->n_bits);
106}
107
108/* Verify that bitmaps A and B have same size. */
109
110static inline void
111bitmap_check_sizes (const_sbitmap a, const_sbitmap b)
112{
113 gcc_checking_assert (a->n_bits == b->n_bits);
114}
115
116/* Test if bit number bitno in the bitmap is set. */
117static inline SBITMAP_ELT_TYPE
118bitmap_bit_p (const_sbitmap map, int bitno)
119{
120 bitmap_check_index (map, bitno);
121
122 size_t i = bitno / SBITMAP_ELT_BITS;
123 unsigned int s = bitno % SBITMAP_ELT_BITS;
124 return (map->elms[i] >> s) & (SBITMAP_ELT_TYPE) 1;
125}
126
127/* Set bit number BITNO in the sbitmap MAP. */
128
129static inline void
130bitmap_set_bit (sbitmap map, int bitno)
131{
132 bitmap_check_index (map, bitno);
133
134 map->elms[bitno / SBITMAP_ELT_BITS]
135 |= (SBITMAP_ELT_TYPE) 1 << (bitno) % SBITMAP_ELT_BITS;
136}
137
138/* Reset bit number BITNO in the sbitmap MAP. */
139
140static inline void
141bitmap_clear_bit (sbitmap map, int bitno)
142{
143 bitmap_check_index (map, bitno);
144
145 map->elms[bitno / SBITMAP_ELT_BITS]
146 &= ~((SBITMAP_ELT_TYPE) 1 << (bitno) % SBITMAP_ELT_BITS);
147}
148
149/* The iterator for sbitmap. */
150struct sbitmap_iterator {
151 /* The pointer to the first word of the bitmap. */
152 const SBITMAP_ELT_TYPE *ptr;
153
154 /* The size of the bitmap. */
155 unsigned int size;
156
157 /* The current word index. */
158 unsigned int word_num;
159
160 /* The current bit index (not modulo SBITMAP_ELT_BITS). */
161 unsigned int bit_num;
162
163 /* The words currently visited. */
164 SBITMAP_ELT_TYPE word;
165};
166
167/* Initialize the iterator I with sbitmap BMP and the initial index
168 MIN. */
169
170static inline void
171bmp_iter_set_init (sbitmap_iterator *i, const_sbitmap bmp,
172 unsigned int min, unsigned *bit_no ATTRIBUTE_UNUSED)
173{
174 i->word_num = min / (unsigned int) SBITMAP_ELT_BITS;
175 i->bit_num = min;
176 i->size = bmp->size;
177 i->ptr = bmp->elms;
178
179 if (i->word_num >= i->size)
180 i->word = 0;
181 else
182 i->word = (i->ptr[i->word_num]
183 >> (i->bit_num % (unsigned int) SBITMAP_ELT_BITS));
184}
185
186/* Return true if we have more bits to visit, in which case *N is set
187 to the index of the bit to be visited. Otherwise, return
188 false. */
189
190static inline bool
191bmp_iter_set (sbitmap_iterator *i, unsigned int *n)
192{
193 /* Skip words that are zeros. */
194 for (; i->word == 0; i->word = i->ptr[i->word_num])
195 {
196 i->word_num++;
197
198 /* If we have reached the end, break. */
199 if (i->word_num >= i->size)
200 return false;
201
202 i->bit_num = i->word_num * SBITMAP_ELT_BITS;
203 }
204
205 /* Skip bits that are zero. */
206 for (; (i->word & 1) == 0; i->word >>= 1)
207 i->bit_num++;
208
209 *n = i->bit_num;
210
211 return true;
212}
213
214/* Advance to the next bit. */
215
216static inline void
217bmp_iter_next (sbitmap_iterator *i, unsigned *bit_no ATTRIBUTE_UNUSED)
218{
219 i->word >>= 1;
220 i->bit_num++;
221}
222
223/* Loop over all elements of SBITMAP, starting with MIN. In each
224 iteration, N is set to the index of the bit being visited. ITER is
225 an instance of sbitmap_iterator used to iterate the bitmap. */
226
227#ifndef EXECUTE_IF_SET_IN_BITMAP
228/* See bitmap.h for the other definition of EXECUTE_IF_SET_IN_BITMAP. */
229#define EXECUTE_IF_SET_IN_BITMAP(BITMAP, MIN, BITNUM, ITER) \
230 for (bmp_iter_set_init (&(ITER), (BITMAP), (MIN), &(BITNUM)); \
231 bmp_iter_set (&(ITER), &(BITNUM)); \
232 bmp_iter_next (&(ITER), &(BITNUM)))
233#endif
234
235inline void sbitmap_free (sbitmap map)
236{
237 free (map);
238}
239
240inline void sbitmap_vector_free (sbitmap * vec)
241{
242 free (vec);
243}
244
245extern void dump_bitmap (FILE *, const_sbitmap);
246extern void debug_raw (const simple_bitmap_def &ref);
247extern void debug_raw (const simple_bitmap_def *ptr);
248extern void dump_bitmap_file (FILE *, const_sbitmap);
249extern void debug (const simple_bitmap_def &ref);
250extern void debug (const simple_bitmap_def *ptr);
251extern void dump_bitmap_vector (FILE *, const char *, const char *, sbitmap *,
252 int);
253extern sbitmap sbitmap_alloc (unsigned int);
254extern sbitmap *sbitmap_vector_alloc (unsigned int, unsigned int);
255extern sbitmap sbitmap_resize (sbitmap, unsigned int, int);
256extern void bitmap_copy (sbitmap, const_sbitmap);
257extern int bitmap_equal_p (const_sbitmap, const_sbitmap);
258extern unsigned int bitmap_count_bits (const_sbitmap);
259extern bool bitmap_empty_p (const_sbitmap);
260extern void bitmap_clear (sbitmap);
261extern void bitmap_clear_range (sbitmap, unsigned, unsigned);
262extern void bitmap_set_range (sbitmap, unsigned, unsigned);
263extern void bitmap_ones (sbitmap);
264extern void bitmap_vector_clear (sbitmap *, unsigned int);
265extern void bitmap_vector_ones (sbitmap *, unsigned int);
266
267extern bool bitmap_ior_and_compl (sbitmap, const_sbitmap,
268 const_sbitmap, const_sbitmap);
269extern void bitmap_and_compl (sbitmap, const_sbitmap, const_sbitmap);
270extern void bitmap_not (sbitmap, const_sbitmap);
271extern bool bitmap_or_and (sbitmap, const_sbitmap,
272 const_sbitmap, const_sbitmap);
273extern bool bitmap_and_or (sbitmap, const_sbitmap,
274 const_sbitmap, const_sbitmap);
275extern bool bitmap_intersect_p (const_sbitmap, const_sbitmap);
276extern bool bitmap_and (sbitmap, const_sbitmap, const_sbitmap);
277extern bool bitmap_ior (sbitmap, const_sbitmap, const_sbitmap);
278extern bool bitmap_xor (sbitmap, const_sbitmap, const_sbitmap);
279extern bool bitmap_subset_p (const_sbitmap, const_sbitmap);
280extern bool bitmap_bit_in_range_p (const_sbitmap, unsigned int, unsigned int);
281
282extern int bitmap_first_set_bit (const_sbitmap);
283extern int bitmap_last_set_bit (const_sbitmap);
284
285extern void debug_bitmap (const_sbitmap);
286extern sbitmap sbitmap_realloc (sbitmap, unsigned int);
287
288/* a class that ties the lifetime of a sbitmap to its scope. */
289class auto_sbitmap
290{
291public:
292 explicit auto_sbitmap (unsigned int size) :
293 m_bitmap (sbitmap_alloc (size)) {}
294 ~auto_sbitmap () { sbitmap_free (m_bitmap); }
295
296 /* Allow calling sbitmap functions on our bitmap. */
297 operator sbitmap () { return m_bitmap; }
298
299private:
300 /* Prevent making a copy that refers to our sbitmap. */
301 auto_sbitmap (const auto_sbitmap &);
302 auto_sbitmap &operator = (const auto_sbitmap &);
303#if __cplusplus >= 201103L
304 auto_sbitmap (auto_sbitmap &&);
305 auto_sbitmap &operator = (auto_sbitmap &&);
306#endif
307
308 /* The bitmap we are managing. */
309 sbitmap m_bitmap;
310};
311
312#endif /* ! GCC_SBITMAP_H */
313