2 Copyright (C) 1999-2020 Free Software Foundation, Inc.
4 This file is part of GCC.
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
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
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/>. */
23 /* Implementation of sets using simple bitmap vectors.
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)
31 This representation is very space-efficient for large non-sparse sets
32 with random access patterns.
34 The following operations can be performed in O(1) time:
36 * set_size : SBITMAP_SIZE
37 * member_p : bitmap_bit_p
38 * add_member : bitmap_set_bit
39 * remove_member : bitmap_clear_bit
41 Most other operations on this set representation are O(U) where U is
42 the size of the set universe:
44 * clear : bitmap_clear
45 * choose_one : bitmap_first_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
56 Some operations on 3 sets that occur frequently in data flow problems
59 * A | (B & C) : bitmap_or_and
60 * A | (B & ~C) : bitmap_ior_and_compl
61 * A & (B | C) : bitmap_and_or
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
69 Allocating a bitmap is done with sbitmap_alloc, and resizing is
70 performed with sbitmap_resize.
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).
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
83 #define SBITMAP_ELT_BITS (HOST_BITS_PER_WIDEST_FAST_INT * 1u)
84 #define SBITMAP_ELT_TYPE unsigned HOST_WIDEST_FAST_INT
86 struct simple_bitmap_def
88 unsigned int n_bits
; /* Number of bits. */
89 unsigned int size
; /* Size in elements. */
90 SBITMAP_ELT_TYPE elms
[1]; /* The elements. */
93 /* Return the set size needed for N elements. */
94 #define SBITMAP_SET_SIZE(N) (((N) + SBITMAP_ELT_BITS - 1) / SBITMAP_ELT_BITS)
96 /* Return the number of bits in BITMAP. */
97 #define SBITMAP_SIZE(BITMAP) ((BITMAP)->n_bits)
99 /* Verify that access at INDEX in bitmap MAP is valid. */
102 bitmap_check_index (const_sbitmap map
, int index
)
104 gcc_checking_assert (index
>= 0);
105 gcc_checking_assert ((unsigned int)index
< map
->n_bits
);
108 /* Verify that bitmaps A and B have same size. */
111 bitmap_check_sizes (const_sbitmap a
, const_sbitmap b
)
113 gcc_checking_assert (a
->n_bits
== b
->n_bits
);
116 /* Test if bit number bitno in the bitmap is set. */
117 static inline SBITMAP_ELT_TYPE
118 bitmap_bit_p (const_sbitmap map
, int bitno
)
120 bitmap_check_index (map
, bitno
);
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;
127 /* Set bit number BITNO in the sbitmap MAP. */
130 bitmap_set_bit (sbitmap map
, int bitno
)
132 bitmap_check_index (map
, bitno
);
134 map
->elms
[bitno
/ SBITMAP_ELT_BITS
]
135 |= (SBITMAP_ELT_TYPE
) 1 << (bitno
) % SBITMAP_ELT_BITS
;
138 /* Reset bit number BITNO in the sbitmap MAP. */
141 bitmap_clear_bit (sbitmap map
, int bitno
)
143 bitmap_check_index (map
, bitno
);
145 map
->elms
[bitno
/ SBITMAP_ELT_BITS
]
146 &= ~((SBITMAP_ELT_TYPE
) 1 << (bitno
) % SBITMAP_ELT_BITS
);
149 /* The iterator for sbitmap. */
150 struct sbitmap_iterator
{
151 /* The pointer to the first word of the bitmap. */
152 const SBITMAP_ELT_TYPE
*ptr
;
154 /* The size of the bitmap. */
157 /* The current word index. */
158 unsigned int word_num
;
160 /* The current bit index (not modulo SBITMAP_ELT_BITS). */
161 unsigned int bit_num
;
163 /* The words currently visited. */
164 SBITMAP_ELT_TYPE word
;
167 /* Initialize the iterator I with sbitmap BMP and the initial index
171 bmp_iter_set_init (sbitmap_iterator
*i
, const_sbitmap bmp
,
172 unsigned int min
, unsigned *bit_no ATTRIBUTE_UNUSED
)
174 i
->word_num
= min
/ (unsigned int) SBITMAP_ELT_BITS
;
179 if (i
->word_num
>= i
->size
)
182 i
->word
= (i
->ptr
[i
->word_num
]
183 >> (i
->bit_num
% (unsigned int) SBITMAP_ELT_BITS
));
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
191 bmp_iter_set (sbitmap_iterator
*i
, unsigned int *n
)
193 /* Skip words that are zeros. */
194 for (; i
->word
== 0; i
->word
= i
->ptr
[i
->word_num
])
198 /* If we have reached the end, break. */
199 if (i
->word_num
>= i
->size
)
202 i
->bit_num
= i
->word_num
* SBITMAP_ELT_BITS
;
205 /* Skip bits that are zero. */
206 for (; (i
->word
& 1) == 0; i
->word
>>= 1)
214 /* Advance to the next bit. */
217 bmp_iter_next (sbitmap_iterator
*i
, unsigned *bit_no ATTRIBUTE_UNUSED
)
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. */
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)))
235 inline void sbitmap_free (sbitmap map
)
240 inline void sbitmap_vector_free (sbitmap
* vec
)
245 extern void dump_bitmap (FILE *, const_sbitmap
);
246 extern void debug_raw (const simple_bitmap_def
&ref
);
247 extern void debug_raw (const simple_bitmap_def
*ptr
);
248 extern void dump_bitmap_file (FILE *, const_sbitmap
);
249 extern void debug (const simple_bitmap_def
&ref
);
250 extern void debug (const simple_bitmap_def
*ptr
);
251 extern void dump_bitmap_vector (FILE *, const char *, const char *, sbitmap
*,
253 extern sbitmap
sbitmap_alloc (unsigned int);
254 extern sbitmap
*sbitmap_vector_alloc (unsigned int, unsigned int);
255 extern sbitmap
sbitmap_resize (sbitmap
, unsigned int, int);
256 extern void bitmap_copy (sbitmap
, const_sbitmap
);
257 extern int bitmap_equal_p (const_sbitmap
, const_sbitmap
);
258 extern unsigned int bitmap_count_bits (const_sbitmap
);
259 extern bool bitmap_empty_p (const_sbitmap
);
260 extern void bitmap_clear (sbitmap
);
261 extern void bitmap_clear_range (sbitmap
, unsigned, unsigned);
262 extern void bitmap_set_range (sbitmap
, unsigned, unsigned);
263 extern void bitmap_ones (sbitmap
);
264 extern void bitmap_vector_clear (sbitmap
*, unsigned int);
265 extern void bitmap_vector_ones (sbitmap
*, unsigned int);
267 extern bool bitmap_ior_and_compl (sbitmap
, const_sbitmap
,
268 const_sbitmap
, const_sbitmap
);
269 extern void bitmap_and_compl (sbitmap
, const_sbitmap
, const_sbitmap
);
270 extern void bitmap_not (sbitmap
, const_sbitmap
);
271 extern bool bitmap_or_and (sbitmap
, const_sbitmap
,
272 const_sbitmap
, const_sbitmap
);
273 extern bool bitmap_and_or (sbitmap
, const_sbitmap
,
274 const_sbitmap
, const_sbitmap
);
275 extern bool bitmap_intersect_p (const_sbitmap
, const_sbitmap
);
276 extern bool bitmap_and (sbitmap
, const_sbitmap
, const_sbitmap
);
277 extern bool bitmap_ior (sbitmap
, const_sbitmap
, const_sbitmap
);
278 extern bool bitmap_xor (sbitmap
, const_sbitmap
, const_sbitmap
);
279 extern bool bitmap_subset_p (const_sbitmap
, const_sbitmap
);
280 extern bool bitmap_bit_in_range_p (const_sbitmap
, unsigned int, unsigned int);
282 extern int bitmap_first_set_bit (const_sbitmap
);
283 extern int bitmap_last_set_bit (const_sbitmap
);
285 extern void debug_bitmap (const_sbitmap
);
286 extern sbitmap
sbitmap_realloc (sbitmap
, unsigned int);
288 /* a class that ties the lifetime of a sbitmap to its scope. */
292 explicit auto_sbitmap (unsigned int size
) :
293 m_bitmap (sbitmap_alloc (size
)) {}
294 ~auto_sbitmap () { sbitmap_free (m_bitmap
); }
296 /* Allow calling sbitmap functions on our bitmap. */
297 operator sbitmap () { return m_bitmap
; }
298 operator const_sbitmap () const { return m_bitmap
; }
301 /* Prevent making a copy that refers to our sbitmap. */
302 auto_sbitmap (const auto_sbitmap
&);
303 auto_sbitmap
&operator = (const auto_sbitmap
&);
304 #if __cplusplus >= 201103L
305 auto_sbitmap (auto_sbitmap
&&);
306 auto_sbitmap
&operator = (auto_sbitmap
&&);
309 /* The bitmap we are managing. */
313 #endif /* ! GCC_SBITMAP_H */