1 /* Simple bitmaps.
2 Copyright (C) 1999-2016 Free Software Foundation, Inc.
3
4 This file is part of GCC.
5
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
10
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
15
16 You should have received a copy of the GNU General Public License
17 along 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
55 Some operations on 3 sets that occur frequently in data flow problems
56 are also implemented:
57
58 * A | (B & C) : bitmap_or_and
59 * A | (B & ~C) : bitmap_ior_and_compl
60 * A & (B | C) : bitmap_and_or
61
62 Most of the set functions have two variants: One that returns non-zero
63 if members were added or removed from the target set, and one that just
64 performs the operation without feedback. The former operations are a
65 bit more expensive but the result can often be used to avoid iterations
66 on other sets.
67
68 Allocating a bitmap is done with sbitmap_alloc, and resizing is
69 performed with sbitmap_resize.
70
71 The storage requirements for simple bitmap sets is O(U) where U is the
72 size of the set universe (colloquially the number of bits in the bitmap).
73
74 This set representation works well for relatively small data flow problems
75 (there are special routines for that, see sbitmap_vector_*). The set
76 operations can be vectorized and there is almost no computating overhead,
77 so that even sparse simple bitmap sets outperform dedicated sparse set
78 representations like linked-list bitmaps. For larger problems, the size
79 overhead of simple bitmap sets gets too high and other set representations
80 have to be used. */
81
82 #define SBITMAP_ELT_BITS (HOST_BITS_PER_WIDEST_FAST_INT * 1u)
83 #define SBITMAP_ELT_TYPE unsigned HOST_WIDEST_FAST_INT
84
85 struct simple_bitmap_def
86 {
87 unsigned char *popcount; /* Population count. */
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 /* Test if bit number bitno in the bitmap is set. */
100 static inline SBITMAP_ELT_TYPE
bitmap_bit_p(const_sbitmap map,int bitno)101 bitmap_bit_p (const_sbitmap map, int bitno)
102 {
103 size_t i = bitno / SBITMAP_ELT_BITS;
104 unsigned int s = bitno % SBITMAP_ELT_BITS;
105 return (map->elms[i] >> s) & (SBITMAP_ELT_TYPE) 1;
106 }
107
108 /* Set bit number BITNO in the sbitmap MAP. */
109
110 static inline void
bitmap_set_bit(sbitmap map,int bitno)111 bitmap_set_bit (sbitmap map, int bitno)
112 {
113 gcc_checking_assert (! map->popcount);
114 map->elms[bitno / SBITMAP_ELT_BITS]
115 |= (SBITMAP_ELT_TYPE) 1 << (bitno) % SBITMAP_ELT_BITS;
116 }
117
118 /* Reset bit number BITNO in the sbitmap MAP. */
119
120 static inline void
bitmap_clear_bit(sbitmap map,int bitno)121 bitmap_clear_bit (sbitmap map, int bitno)
122 {
123 gcc_checking_assert (! map->popcount);
124 map->elms[bitno / SBITMAP_ELT_BITS]
125 &= ~((SBITMAP_ELT_TYPE) 1 << (bitno) % SBITMAP_ELT_BITS);
126 }
127
128 /* The iterator for sbitmap. */
129 struct sbitmap_iterator {
130 /* The pointer to the first word of the bitmap. */
131 const SBITMAP_ELT_TYPE *ptr;
132
133 /* The size of the bitmap. */
134 unsigned int size;
135
136 /* The current word index. */
137 unsigned int word_num;
138
139 /* The current bit index (not modulo SBITMAP_ELT_BITS). */
140 unsigned int bit_num;
141
142 /* The words currently visited. */
143 SBITMAP_ELT_TYPE word;
144 };
145
146 /* Initialize the iterator I with sbitmap BMP and the initial index
147 MIN. */
148
149 static inline void
bmp_iter_set_init(sbitmap_iterator * i,const_sbitmap bmp,unsigned int min,unsigned * bit_no ATTRIBUTE_UNUSED)150 bmp_iter_set_init (sbitmap_iterator *i, const_sbitmap bmp,
151 unsigned int min, unsigned *bit_no ATTRIBUTE_UNUSED)
152 {
153 i->word_num = min / (unsigned int) SBITMAP_ELT_BITS;
154 i->bit_num = min;
155 i->size = bmp->size;
156 i->ptr = bmp->elms;
157
158 if (i->word_num >= i->size)
159 i->word = 0;
160 else
161 i->word = (i->ptr[i->word_num]
162 >> (i->bit_num % (unsigned int) SBITMAP_ELT_BITS));
163 }
164
165 /* Return true if we have more bits to visit, in which case *N is set
166 to the index of the bit to be visited. Otherwise, return
167 false. */
168
169 static inline bool
bmp_iter_set(sbitmap_iterator * i,unsigned int * n)170 bmp_iter_set (sbitmap_iterator *i, unsigned int *n)
171 {
172 /* Skip words that are zeros. */
173 for (; i->word == 0; i->word = i->ptr[i->word_num])
174 {
175 i->word_num++;
176
177 /* If we have reached the end, break. */
178 if (i->word_num >= i->size)
179 return false;
180
181 i->bit_num = i->word_num * SBITMAP_ELT_BITS;
182 }
183
184 /* Skip bits that are zero. */
185 for (; (i->word & 1) == 0; i->word >>= 1)
186 i->bit_num++;
187
188 *n = i->bit_num;
189
190 return true;
191 }
192
193 /* Advance to the next bit. */
194
195 static inline void
bmp_iter_next(sbitmap_iterator * i,unsigned * bit_no ATTRIBUTE_UNUSED)196 bmp_iter_next (sbitmap_iterator *i, unsigned *bit_no ATTRIBUTE_UNUSED)
197 {
198 i->word >>= 1;
199 i->bit_num++;
200 }
201
202 /* Loop over all elements of SBITMAP, starting with MIN. In each
203 iteration, N is set to the index of the bit being visited. ITER is
204 an instance of sbitmap_iterator used to iterate the bitmap. */
205
206 #ifndef EXECUTE_IF_SET_IN_BITMAP
207 /* See bitmap.h for the other definition of EXECUTE_IF_SET_IN_BITMAP. */
208 #define EXECUTE_IF_SET_IN_BITMAP(BITMAP, MIN, BITNUM, ITER) \
209 for (bmp_iter_set_init (&(ITER), (BITMAP), (MIN), &(BITNUM)); \
210 bmp_iter_set (&(ITER), &(BITNUM)); \
211 bmp_iter_next (&(ITER), &(BITNUM)))
212 #endif
213
sbitmap_free(sbitmap map)214 inline void sbitmap_free (sbitmap map)
215 {
216 free (map->popcount);
217 free (map);
218 }
219
sbitmap_vector_free(sbitmap * vec)220 inline void sbitmap_vector_free (sbitmap * vec)
221 {
222 free (vec);
223 }
224
225 extern void dump_bitmap (FILE *, const_sbitmap);
226 extern void debug_raw (const simple_bitmap_def &ref);
227 extern void debug_raw (const simple_bitmap_def *ptr);
228 extern void dump_bitmap_file (FILE *, const_sbitmap);
229 extern void debug (const simple_bitmap_def &ref);
230 extern void debug (const simple_bitmap_def *ptr);
231 extern void dump_bitmap_vector (FILE *, const char *, const char *, sbitmap *,
232 int);
233 extern sbitmap sbitmap_alloc (unsigned int);
234 extern sbitmap sbitmap_alloc_with_popcount (unsigned int);
235 extern sbitmap *sbitmap_vector_alloc (unsigned int, unsigned int);
236 extern sbitmap sbitmap_resize (sbitmap, unsigned int, int);
237 extern void bitmap_copy (sbitmap, const_sbitmap);
238 extern int bitmap_equal_p (const_sbitmap, const_sbitmap);
239 extern bool bitmap_empty_p (const_sbitmap);
240 extern void bitmap_clear (sbitmap);
241 extern void bitmap_ones (sbitmap);
242 extern void bitmap_vector_clear (sbitmap *, unsigned int);
243 extern void bitmap_vector_ones (sbitmap *, unsigned int);
244
245 extern bool bitmap_ior_and_compl (sbitmap, const_sbitmap,
246 const_sbitmap, const_sbitmap);
247 extern void bitmap_and_compl (sbitmap, const_sbitmap, const_sbitmap);
248 extern void bitmap_not (sbitmap, const_sbitmap);
249 extern bool bitmap_or_and (sbitmap, const_sbitmap,
250 const_sbitmap, const_sbitmap);
251 extern bool bitmap_and_or (sbitmap, const_sbitmap,
252 const_sbitmap, const_sbitmap);
253 extern bool bitmap_intersect_p (const_sbitmap, const_sbitmap);
254 extern bool bitmap_and (sbitmap, const_sbitmap, const_sbitmap);
255 extern bool bitmap_ior (sbitmap, const_sbitmap, const_sbitmap);
256 extern bool bitmap_xor (sbitmap, const_sbitmap, const_sbitmap);
257 extern bool bitmap_subset_p (const_sbitmap, const_sbitmap);
258
259 extern int bitmap_first_set_bit (const_sbitmap);
260 extern int bitmap_last_set_bit (const_sbitmap);
261
262 extern void debug_bitmap (const_sbitmap);
263 extern sbitmap sbitmap_realloc (sbitmap, unsigned int);
264 extern unsigned long sbitmap_popcount (const_sbitmap, unsigned long);
265 #endif /* ! GCC_SBITMAP_H */
266