1/* Functions to support general ended bitmaps.
2 Copyright (C) 1997-2017 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_BITMAP_H
21#define GCC_BITMAP_H
22
23/* Implementation of sparse integer sets as a linked list.
24
25 This sparse set representation is suitable for sparse sets with an
26 unknown (a priori) universe. The set is represented as a double-linked
27 list of container nodes (struct bitmap_element). Each node consists
28 of an index for the first member that could be held in the container,
29 a small array of integers that represent the members in the container,
30 and pointers to the next and previous element in the linked list. The
31 elements in the list are sorted in ascending order, i.e. the head of
32 the list holds the element with the smallest member of the set.
33
34 For a given member I in the set:
35 - the element for I will have index is I / (bits per element)
36 - the position for I within element is I % (bits per element)
37
38 This representation is very space-efficient for large sparse sets, and
39 the size of the set can be changed dynamically without much overhead.
40 An important parameter is the number of bits per element. In this
41 implementation, there are 128 bits per element. This results in a
42 high storage overhead *per element*, but a small overall overhead if
43 the set is very sparse.
44
45 The downside is that many operations are relatively slow because the
46 linked list has to be traversed to test membership (i.e. member_p/
47 add_member/remove_member). To improve the performance of this set
48 representation, the last accessed element and its index are cached.
49 For membership tests on members close to recently accessed members,
50 the cached last element improves membership test to a constant-time
51 operation.
52
53 The following operations can always be performed in O(1) time:
54
55 * clear : bitmap_clear
56 * choose_one : (not implemented, but could be
57 implemented in constant time)
58
59 The following operations can be performed in O(E) time worst-case (with
60 E the number of elements in the linked list), but in O(1) time with a
61 suitable access patterns:
62
63 * member_p : bitmap_bit_p
64 * add_member : bitmap_set_bit
65 * remove_member : bitmap_clear_bit
66
67 The following operations can be performed in O(E) time:
68
69 * cardinality : bitmap_count_bits
70 * set_size : bitmap_last_set_bit (but this could
71 in constant time with a pointer to
72 the last element in the chain)
73
74 Additionally, the linked-list sparse set representation supports
75 enumeration of the members in O(E) time:
76
77 * forall : EXECUTE_IF_SET_IN_BITMAP
78 * set_copy : bitmap_copy
79 * set_intersection : bitmap_intersect_p /
80 bitmap_and / bitmap_and_into /
81 EXECUTE_IF_AND_IN_BITMAP
82 * set_union : bitmap_ior / bitmap_ior_into
83 * set_difference : bitmap_intersect_compl_p /
84 bitmap_and_comp / bitmap_and_comp_into /
85 EXECUTE_IF_AND_COMPL_IN_BITMAP
86 * set_disjuction : bitmap_xor_comp / bitmap_xor_comp_into
87 * set_compare : bitmap_equal_p
88
89 Some operations on 3 sets that occur frequently in data flow problems
90 are also implemented:
91
92 * A | (B & C) : bitmap_ior_and_into
93 * A | (B & ~C) : bitmap_ior_and_compl /
94 bitmap_ior_and_compl_into
95
96 The storage requirements for linked-list sparse sets are O(E), with E->N
97 in the worst case (a sparse set with large distances between the values
98 of the set members).
99
100 The linked-list set representation works well for problems involving very
101 sparse sets. The canonical example in GCC is, of course, the "set of
102 sets" for some CFG-based data flow problems (liveness analysis, dominance
103 frontiers, etc.).
104
105 This representation also works well for data flow problems where the size
106 of the set may grow dynamically, but care must be taken that the member_p,
107 add_member, and remove_member operations occur with a suitable access
108 pattern.
109
110 For random-access sets with a known, relatively small universe size, the
111 SparseSet or simple bitmap representations may be more efficient than a
112 linked-list set. For random-access sets of unknown universe, a hash table
113 or a balanced binary tree representation is likely to be a more suitable
114 choice.
115
116 Traversing linked lists is usually cache-unfriendly, even with the last
117 accessed element cached.
118
119 Cache performance can be improved by keeping the elements in the set
120 grouped together in memory, using a dedicated obstack for a set (or group
121 of related sets). Elements allocated on obstacks are released to a
122 free-list and taken off the free list. If multiple sets are allocated on
123 the same obstack, elements freed from one set may be re-used for one of
124 the other sets. This usually helps avoid cache misses.
125
126 A single free-list is used for all sets allocated in GGC space. This is
127 bad for persistent sets, so persistent sets should be allocated on an
128 obstack whenever possible. */
129
130#include "obstack.h"
131
132/* Bitmap memory usage. */
133struct bitmap_usage: public mem_usage
134{
135 /* Default contructor. */
136 bitmap_usage (): m_nsearches (0), m_search_iter (0) {}
137 /* Constructor. */
138 bitmap_usage (size_t allocated, size_t times, size_t peak,
139 uint64_t nsearches, uint64_t search_iter)
140 : mem_usage (allocated, times, peak),
141 m_nsearches (nsearches), m_search_iter (search_iter) {}
142
143 /* Sum the usage with SECOND usage. */
144 bitmap_usage
145 operator+ (const bitmap_usage &second)
146 {
147 return bitmap_usage (m_allocated + second.m_allocated,
148 m_times + second.m_times,
149 m_peak + second.m_peak,
150 m_nsearches + second.m_nsearches,
151 m_search_iter + second.m_search_iter);
152 }
153
154 /* Dump usage coupled to LOC location, where TOTAL is sum of all rows. */
155 inline void
156 dump (mem_location *loc, mem_usage &total) const
157 {
158 char *location_string = loc->to_string ();
159
160 fprintf (stderr, "%-48s %10" PRIu64 ":%5.1f%%"
161 "%10" PRIu64 "%10" PRIu64 ":%5.1f%%"
162 "%12" PRIu64 "%12" PRIu64 "%10s\n",
163 location_string, (uint64_t)m_allocated,
164 get_percent (m_allocated, total.m_allocated),
165 (uint64_t)m_peak, (uint64_t)m_times,
166 get_percent (m_times, total.m_times),
167 m_nsearches, m_search_iter,
168 loc->m_ggc ? "ggc" : "heap");
169
170 free (location_string);
171 }
172
173 /* Dump header with NAME. */
174 static inline void
175 dump_header (const char *name)
176 {
177 fprintf (stderr, "%-48s %11s%16s%17s%12s%12s%10s\n", name, "Leak", "Peak",
178 "Times", "N searches", "Search iter", "Type");
179 print_dash_line ();
180 }
181
182 /* Number search operations. */
183 uint64_t m_nsearches;
184 /* Number of search iterations. */
185 uint64_t m_search_iter;
186};
187
188/* Bitmap memory description. */
189extern mem_alloc_description<bitmap_usage> bitmap_mem_desc;
190
191/* Fundamental storage type for bitmap. */
192
193typedef unsigned long BITMAP_WORD;
194/* BITMAP_WORD_BITS needs to be unsigned, but cannot contain casts as
195 it is used in preprocessor directives -- hence the 1u. */
196#define BITMAP_WORD_BITS (CHAR_BIT * SIZEOF_LONG * 1u)
197
198/* Number of words to use for each element in the linked list. */
199
200#ifndef BITMAP_ELEMENT_WORDS
201#define BITMAP_ELEMENT_WORDS ((128 + BITMAP_WORD_BITS - 1) / BITMAP_WORD_BITS)
202#endif
203
204/* Number of bits in each actual element of a bitmap. */
205
206#define BITMAP_ELEMENT_ALL_BITS (BITMAP_ELEMENT_WORDS * BITMAP_WORD_BITS)
207
208/* Obstack for allocating bitmaps and elements from. */
209struct GTY (()) bitmap_obstack {
210 struct bitmap_element *elements;
211 struct bitmap_head *heads;
212 struct obstack GTY ((skip)) obstack;
213};
214
215/* Bitmap set element. We use a linked list to hold only the bits that
216 are set. This allows for use to grow the bitset dynamically without
217 having to realloc and copy a giant bit array.
218
219 The free list is implemented as a list of lists. There is one
220 outer list connected together by prev fields. Each element of that
221 outer is an inner list (that may consist only of the outer list
222 element) that are connected by the next fields. The prev pointer
223 is undefined for interior elements. This allows
224 bitmap_elt_clear_from to be implemented in unit time rather than
225 linear in the number of elements to be freed. */
226
227struct GTY((chain_next ("%h.next"), chain_prev ("%h.prev"))) bitmap_element {
228 struct bitmap_element *next; /* Next element. */
229 struct bitmap_element *prev; /* Previous element. */
230 unsigned int indx; /* regno/BITMAP_ELEMENT_ALL_BITS. */
231 BITMAP_WORD bits[BITMAP_ELEMENT_WORDS]; /* Bits that are set. */
232};
233
234/* Head of bitmap linked list. The 'current' member points to something
235 already pointed to by the chain started by first, so GTY((skip)) it. */
236
237struct GTY(()) bitmap_head {
238 unsigned int indx; /* Index of last element looked at. */
239 unsigned int descriptor_id; /* Unique identifier for the allocation
240 site of this bitmap, for detailed
241 statistics gathering. */
242 bitmap_element *first; /* First element in linked list. */
243 bitmap_element * GTY((skip(""))) current; /* Last element looked at. */
244 bitmap_obstack *obstack; /* Obstack to allocate elements from.
245 If NULL, then use GGC allocation. */
246};
247
248/* Global data */
249extern bitmap_element bitmap_zero_bits; /* Zero bitmap element */
250extern bitmap_obstack bitmap_default_obstack; /* Default bitmap obstack */
251
252/* Clear a bitmap by freeing up the linked list. */
253extern void bitmap_clear (bitmap);
254
255/* Copy a bitmap to another bitmap. */
256extern void bitmap_copy (bitmap, const_bitmap);
257
258/* Move a bitmap to another bitmap. */
259extern void bitmap_move (bitmap, bitmap);
260
261/* True if two bitmaps are identical. */
262extern bool bitmap_equal_p (const_bitmap, const_bitmap);
263
264/* True if the bitmaps intersect (their AND is non-empty). */
265extern bool bitmap_intersect_p (const_bitmap, const_bitmap);
266
267/* True if the complement of the second intersects the first (their
268 AND_COMPL is non-empty). */
269extern bool bitmap_intersect_compl_p (const_bitmap, const_bitmap);
270
271/* True if MAP is an empty bitmap. */
272inline bool bitmap_empty_p (const_bitmap map)
273{
274 return !map->first;
275}
276
277/* True if the bitmap has only a single bit set. */
278extern bool bitmap_single_bit_set_p (const_bitmap);
279
280/* Count the number of bits set in the bitmap. */
281extern unsigned long bitmap_count_bits (const_bitmap);
282
283/* Count the number of unique bits set across the two bitmaps. */
284extern unsigned long bitmap_count_unique_bits (const_bitmap, const_bitmap);
285
286/* Boolean operations on bitmaps. The _into variants are two operand
287 versions that modify the first source operand. The other variants
288 are three operand versions that to not destroy the source bitmaps.
289 The operations supported are &, & ~, |, ^. */
290extern void bitmap_and (bitmap, const_bitmap, const_bitmap);
291extern bool bitmap_and_into (bitmap, const_bitmap);
292extern bool bitmap_and_compl (bitmap, const_bitmap, const_bitmap);
293extern bool bitmap_and_compl_into (bitmap, const_bitmap);
294#define bitmap_compl_and(DST, A, B) bitmap_and_compl (DST, B, A)
295extern void bitmap_compl_and_into (bitmap, const_bitmap);
296extern void bitmap_clear_range (bitmap, unsigned int, unsigned int);
297extern void bitmap_set_range (bitmap, unsigned int, unsigned int);
298extern bool bitmap_ior (bitmap, const_bitmap, const_bitmap);
299extern bool bitmap_ior_into (bitmap, const_bitmap);
300extern void bitmap_xor (bitmap, const_bitmap, const_bitmap);
301extern void bitmap_xor_into (bitmap, const_bitmap);
302
303/* DST = A | (B & C). Return true if DST changes. */
304extern bool bitmap_ior_and_into (bitmap DST, const_bitmap B, const_bitmap C);
305/* DST = A | (B & ~C). Return true if DST changes. */
306extern bool bitmap_ior_and_compl (bitmap DST, const_bitmap A,
307 const_bitmap B, const_bitmap C);
308/* A |= (B & ~C). Return true if A changes. */
309extern bool bitmap_ior_and_compl_into (bitmap A,
310 const_bitmap B, const_bitmap C);
311
312/* Clear a single bit in a bitmap. Return true if the bit changed. */
313extern bool bitmap_clear_bit (bitmap, int);
314
315/* Set a single bit in a bitmap. Return true if the bit changed. */
316extern bool bitmap_set_bit (bitmap, int);
317
318/* Return true if a register is set in a register set. */
319extern int bitmap_bit_p (bitmap, int);
320
321/* Debug functions to print a bitmap linked list. */
322extern void debug_bitmap (const_bitmap);
323extern void debug_bitmap_file (FILE *, const_bitmap);
324
325/* Print a bitmap. */
326extern void bitmap_print (FILE *, const_bitmap, const char *, const char *);
327
328/* Initialize and release a bitmap obstack. */
329extern void bitmap_obstack_initialize (bitmap_obstack *);
330extern void bitmap_obstack_release (bitmap_obstack *);
331extern void bitmap_register (bitmap MEM_STAT_DECL);
332extern void dump_bitmap_statistics (void);
333
334/* Initialize a bitmap header. OBSTACK indicates the bitmap obstack
335 to allocate from, NULL for GC'd bitmap. */
336
337static inline void
338bitmap_initialize (bitmap head, bitmap_obstack *obstack CXX_MEM_STAT_INFO)
339{
340 head->first = head->current = NULL;
341 head->obstack = obstack;
342 if (GATHER_STATISTICS)
343 bitmap_register (head PASS_MEM_STAT);
344}
345
346/* Allocate and free bitmaps from obstack, malloc and gc'd memory. */
347extern bitmap bitmap_alloc (bitmap_obstack *obstack CXX_MEM_STAT_INFO);
348#define BITMAP_ALLOC bitmap_alloc
349extern bitmap bitmap_gc_alloc (ALONE_CXX_MEM_STAT_INFO);
350#define BITMAP_GGC_ALLOC bitmap_gc_alloc
351extern void bitmap_obstack_free (bitmap);
352
353/* A few compatibility/functions macros for compatibility with sbitmaps */
354inline void dump_bitmap (FILE *file, const_bitmap map)
355{
356 bitmap_print (file, map, "", "\n");
357}
358extern void debug (const bitmap_head &ref);
359extern void debug (const bitmap_head *ptr);
360
361extern unsigned bitmap_first_set_bit (const_bitmap);
362extern unsigned bitmap_last_set_bit (const_bitmap);
363
364/* Compute bitmap hash (for purposes of hashing etc.) */
365extern hashval_t bitmap_hash (const_bitmap);
366
367/* Do any cleanup needed on a bitmap when it is no longer used. */
368#define BITMAP_FREE(BITMAP) \
369 ((void) (bitmap_obstack_free ((bitmap) BITMAP), (BITMAP) = (bitmap) NULL))
370
371/* Iterator for bitmaps. */
372
373struct bitmap_iterator
374{
375 /* Pointer to the current bitmap element. */
376 bitmap_element *elt1;
377
378 /* Pointer to 2nd bitmap element when two are involved. */
379 bitmap_element *elt2;
380
381 /* Word within the current element. */
382 unsigned word_no;
383
384 /* Contents of the actually processed word. When finding next bit
385 it is shifted right, so that the actual bit is always the least
386 significant bit of ACTUAL. */
387 BITMAP_WORD bits;
388};
389
390/* Initialize a single bitmap iterator. START_BIT is the first bit to
391 iterate from. */
392
393static inline void
394bmp_iter_set_init (bitmap_iterator *bi, const_bitmap map,
395 unsigned start_bit, unsigned *bit_no)
396{
397 bi->elt1 = map->first;
398 bi->elt2 = NULL;
399
400 /* Advance elt1 until it is not before the block containing start_bit. */
401 while (1)
402 {
403 if (!bi->elt1)
404 {
405 bi->elt1 = &bitmap_zero_bits;
406 break;
407 }
408
409 if (bi->elt1->indx >= start_bit / BITMAP_ELEMENT_ALL_BITS)
410 break;
411 bi->elt1 = bi->elt1->next;
412 }
413
414 /* We might have gone past the start bit, so reinitialize it. */
415 if (bi->elt1->indx != start_bit / BITMAP_ELEMENT_ALL_BITS)
416 start_bit = bi->elt1->indx * BITMAP_ELEMENT_ALL_BITS;
417
418 /* Initialize for what is now start_bit. */
419 bi->word_no = start_bit / BITMAP_WORD_BITS % BITMAP_ELEMENT_WORDS;
420 bi->bits = bi->elt1->bits[bi->word_no];
421 bi->bits >>= start_bit % BITMAP_WORD_BITS;
422
423 /* If this word is zero, we must make sure we're not pointing at the
424 first bit, otherwise our incrementing to the next word boundary
425 will fail. It won't matter if this increment moves us into the
426 next word. */
427 start_bit += !bi->bits;
428
429 *bit_no = start_bit;
430}
431
432/* Initialize an iterator to iterate over the intersection of two
433 bitmaps. START_BIT is the bit to commence from. */
434
435static inline void
436bmp_iter_and_init (bitmap_iterator *bi, const_bitmap map1, const_bitmap map2,
437 unsigned start_bit, unsigned *bit_no)
438{
439 bi->elt1 = map1->first;
440 bi->elt2 = map2->first;
441
442 /* Advance elt1 until it is not before the block containing
443 start_bit. */
444 while (1)
445 {
446 if (!bi->elt1)
447 {
448 bi->elt2 = NULL;
449 break;
450 }
451
452 if (bi->elt1->indx >= start_bit / BITMAP_ELEMENT_ALL_BITS)
453 break;
454 bi->elt1 = bi->elt1->next;
455 }
456
457 /* Advance elt2 until it is not before elt1. */
458 while (1)
459 {
460 if (!bi->elt2)
461 {
462 bi->elt1 = bi->elt2 = &bitmap_zero_bits;
463 break;
464 }
465
466 if (bi->elt2->indx >= bi->elt1->indx)
467 break;
468 bi->elt2 = bi->elt2->next;
469 }
470
471 /* If we're at the same index, then we have some intersecting bits. */
472 if (bi->elt1->indx == bi->elt2->indx)
473 {
474 /* We might have advanced beyond the start_bit, so reinitialize
475 for that. */
476 if (bi->elt1->indx != start_bit / BITMAP_ELEMENT_ALL_BITS)
477 start_bit = bi->elt1->indx * BITMAP_ELEMENT_ALL_BITS;
478
479 bi->word_no = start_bit / BITMAP_WORD_BITS % BITMAP_ELEMENT_WORDS;
480 bi->bits = bi->elt1->bits[bi->word_no] & bi->elt2->bits[bi->word_no];
481 bi->bits >>= start_bit % BITMAP_WORD_BITS;
482 }
483 else
484 {
485 /* Otherwise we must immediately advance elt1, so initialize for
486 that. */
487 bi->word_no = BITMAP_ELEMENT_WORDS - 1;
488 bi->bits = 0;
489 }
490
491 /* If this word is zero, we must make sure we're not pointing at the
492 first bit, otherwise our incrementing to the next word boundary
493 will fail. It won't matter if this increment moves us into the
494 next word. */
495 start_bit += !bi->bits;
496
497 *bit_no = start_bit;
498}
499
500/* Initialize an iterator to iterate over the bits in MAP1 & ~MAP2.
501 */
502
503static inline void
504bmp_iter_and_compl_init (bitmap_iterator *bi,
505 const_bitmap map1, const_bitmap map2,
506 unsigned start_bit, unsigned *bit_no)
507{
508 bi->elt1 = map1->first;
509 bi->elt2 = map2->first;
510
511 /* Advance elt1 until it is not before the block containing start_bit. */
512 while (1)
513 {
514 if (!bi->elt1)
515 {
516 bi->elt1 = &bitmap_zero_bits;
517 break;
518 }
519
520 if (bi->elt1->indx >= start_bit / BITMAP_ELEMENT_ALL_BITS)
521 break;
522 bi->elt1 = bi->elt1->next;
523 }
524
525 /* Advance elt2 until it is not before elt1. */
526 while (bi->elt2 && bi->elt2->indx < bi->elt1->indx)
527 bi->elt2 = bi->elt2->next;
528
529 /* We might have advanced beyond the start_bit, so reinitialize for
530 that. */
531 if (bi->elt1->indx != start_bit / BITMAP_ELEMENT_ALL_BITS)
532 start_bit = bi->elt1->indx * BITMAP_ELEMENT_ALL_BITS;
533
534 bi->word_no = start_bit / BITMAP_WORD_BITS % BITMAP_ELEMENT_WORDS;
535 bi->bits = bi->elt1->bits[bi->word_no];
536 if (bi->elt2 && bi->elt1->indx == bi->elt2->indx)
537 bi->bits &= ~bi->elt2->bits[bi->word_no];
538 bi->bits >>= start_bit % BITMAP_WORD_BITS;
539
540 /* If this word is zero, we must make sure we're not pointing at the
541 first bit, otherwise our incrementing to the next word boundary
542 will fail. It won't matter if this increment moves us into the
543 next word. */
544 start_bit += !bi->bits;
545
546 *bit_no = start_bit;
547}
548
549/* Advance to the next bit in BI. We don't advance to the next
550 nonzero bit yet. */
551
552static inline void
553bmp_iter_next (bitmap_iterator *bi, unsigned *bit_no)
554{
555 bi->bits >>= 1;
556 *bit_no += 1;
557}
558
559/* Advance to first set bit in BI. */
560
561static inline void
562bmp_iter_next_bit (bitmap_iterator * bi, unsigned *bit_no)
563{
564#if (GCC_VERSION >= 3004)
565 {
566 unsigned int n = __builtin_ctzl (bi->bits);
567 gcc_assert (sizeof (unsigned long) == sizeof (BITMAP_WORD));
568 bi->bits >>= n;
569 *bit_no += n;
570 }
571#else
572 while (!(bi->bits & 1))
573 {
574 bi->bits >>= 1;
575 *bit_no += 1;
576 }
577#endif
578}
579
580/* Advance to the next nonzero bit of a single bitmap, we will have
581 already advanced past the just iterated bit. Return true if there
582 is a bit to iterate. */
583
584static inline bool
585bmp_iter_set (bitmap_iterator *bi, unsigned *bit_no)
586{
587 /* If our current word is nonzero, it contains the bit we want. */
588 if (bi->bits)
589 {
590 next_bit:
591 bmp_iter_next_bit (bi, bit_no);
592 return true;
593 }
594
595 /* Round up to the word boundary. We might have just iterated past
596 the end of the last word, hence the -1. It is not possible for
597 bit_no to point at the beginning of the now last word. */
598 *bit_no = ((*bit_no + BITMAP_WORD_BITS - 1)
599 / BITMAP_WORD_BITS * BITMAP_WORD_BITS);
600 bi->word_no++;
601
602 while (1)
603 {
604 /* Find the next nonzero word in this elt. */
605 while (bi->word_no != BITMAP_ELEMENT_WORDS)
606 {
607 bi->bits = bi->elt1->bits[bi->word_no];
608 if (bi->bits)
609 goto next_bit;
610 *bit_no += BITMAP_WORD_BITS;
611 bi->word_no++;
612 }
613
614 /* Make sure we didn't remove the element while iterating. */
615 gcc_checking_assert (bi->elt1->indx != -1U);
616
617 /* Advance to the next element. */
618 bi->elt1 = bi->elt1->next;
619 if (!bi->elt1)
620 return false;
621 *bit_no = bi->elt1->indx * BITMAP_ELEMENT_ALL_BITS;
622 bi->word_no = 0;
623 }
624}
625
626/* Advance to the next nonzero bit of an intersecting pair of
627 bitmaps. We will have already advanced past the just iterated bit.
628 Return true if there is a bit to iterate. */
629
630static inline bool
631bmp_iter_and (bitmap_iterator *bi, unsigned *bit_no)
632{
633 /* If our current word is nonzero, it contains the bit we want. */
634 if (bi->bits)
635 {
636 next_bit:
637 bmp_iter_next_bit (bi, bit_no);
638 return true;
639 }
640
641 /* Round up to the word boundary. We might have just iterated past
642 the end of the last word, hence the -1. It is not possible for
643 bit_no to point at the beginning of the now last word. */
644 *bit_no = ((*bit_no + BITMAP_WORD_BITS - 1)
645 / BITMAP_WORD_BITS * BITMAP_WORD_BITS);
646 bi->word_no++;
647
648 while (1)
649 {
650 /* Find the next nonzero word in this elt. */
651 while (bi->word_no != BITMAP_ELEMENT_WORDS)
652 {
653 bi->bits = bi->elt1->bits[bi->word_no] & bi->elt2->bits[bi->word_no];
654 if (bi->bits)
655 goto next_bit;
656 *bit_no += BITMAP_WORD_BITS;
657 bi->word_no++;
658 }
659
660 /* Advance to the next identical element. */
661 do
662 {
663 /* Make sure we didn't remove the element while iterating. */
664 gcc_checking_assert (bi->elt1->indx != -1U);
665
666 /* Advance elt1 while it is less than elt2. We always want
667 to advance one elt. */
668 do
669 {
670 bi->elt1 = bi->elt1->next;
671 if (!bi->elt1)
672 return false;
673 }
674 while (bi->elt1->indx < bi->elt2->indx);
675
676 /* Make sure we didn't remove the element while iterating. */
677 gcc_checking_assert (bi->elt2->indx != -1U);
678
679 /* Advance elt2 to be no less than elt1. This might not
680 advance. */
681 while (bi->elt2->indx < bi->elt1->indx)
682 {
683 bi->elt2 = bi->elt2->next;
684 if (!bi->elt2)
685 return false;
686 }
687 }
688 while (bi->elt1->indx != bi->elt2->indx);
689
690 *bit_no = bi->elt1->indx * BITMAP_ELEMENT_ALL_BITS;
691 bi->word_no = 0;
692 }
693}
694
695/* Advance to the next nonzero bit in the intersection of
696 complemented bitmaps. We will have already advanced past the just
697 iterated bit. */
698
699static inline bool
700bmp_iter_and_compl (bitmap_iterator *bi, unsigned *bit_no)
701{
702 /* If our current word is nonzero, it contains the bit we want. */
703 if (bi->bits)
704 {
705 next_bit:
706 bmp_iter_next_bit (bi, bit_no);
707 return true;
708 }
709
710 /* Round up to the word boundary. We might have just iterated past
711 the end of the last word, hence the -1. It is not possible for
712 bit_no to point at the beginning of the now last word. */
713 *bit_no = ((*bit_no + BITMAP_WORD_BITS - 1)
714 / BITMAP_WORD_BITS * BITMAP_WORD_BITS);
715 bi->word_no++;
716
717 while (1)
718 {
719 /* Find the next nonzero word in this elt. */
720 while (bi->word_no != BITMAP_ELEMENT_WORDS)
721 {
722 bi->bits = bi->elt1->bits[bi->word_no];
723 if (bi->elt2 && bi->elt2->indx == bi->elt1->indx)
724 bi->bits &= ~bi->elt2->bits[bi->word_no];
725 if (bi->bits)
726 goto next_bit;
727 *bit_no += BITMAP_WORD_BITS;
728 bi->word_no++;
729 }
730
731 /* Make sure we didn't remove the element while iterating. */
732 gcc_checking_assert (bi->elt1->indx != -1U);
733
734 /* Advance to the next element of elt1. */
735 bi->elt1 = bi->elt1->next;
736 if (!bi->elt1)
737 return false;
738
739 /* Make sure we didn't remove the element while iterating. */
740 gcc_checking_assert (! bi->elt2 || bi->elt2->indx != -1U);
741
742 /* Advance elt2 until it is no less than elt1. */
743 while (bi->elt2 && bi->elt2->indx < bi->elt1->indx)
744 bi->elt2 = bi->elt2->next;
745
746 *bit_no = bi->elt1->indx * BITMAP_ELEMENT_ALL_BITS;
747 bi->word_no = 0;
748 }
749}
750
751/* If you are modifying a bitmap you are currently iterating over you
752 have to ensure to
753 - never remove the current bit;
754 - if you set or clear a bit before the current bit this operation
755 will not affect the set of bits you are visiting during the iteration;
756 - if you set or clear a bit after the current bit it is unspecified
757 whether that affects the set of bits you are visiting during the
758 iteration.
759 If you want to remove the current bit you can delay this to the next
760 iteration (and after the iteration in case the last iteration is
761 affected). */
762
763/* Loop over all bits set in BITMAP, starting with MIN and setting
764 BITNUM to the bit number. ITER is a bitmap iterator. BITNUM
765 should be treated as a read-only variable as it contains loop
766 state. */
767
768#ifndef EXECUTE_IF_SET_IN_BITMAP
769/* See sbitmap.h for the other definition of EXECUTE_IF_SET_IN_BITMAP. */
770#define EXECUTE_IF_SET_IN_BITMAP(BITMAP, MIN, BITNUM, ITER) \
771 for (bmp_iter_set_init (&(ITER), (BITMAP), (MIN), &(BITNUM)); \
772 bmp_iter_set (&(ITER), &(BITNUM)); \
773 bmp_iter_next (&(ITER), &(BITNUM)))
774#endif
775
776/* Loop over all the bits set in BITMAP1 & BITMAP2, starting with MIN
777 and setting BITNUM to the bit number. ITER is a bitmap iterator.
778 BITNUM should be treated as a read-only variable as it contains
779 loop state. */
780
781#define EXECUTE_IF_AND_IN_BITMAP(BITMAP1, BITMAP2, MIN, BITNUM, ITER) \
782 for (bmp_iter_and_init (&(ITER), (BITMAP1), (BITMAP2), (MIN), \
783 &(BITNUM)); \
784 bmp_iter_and (&(ITER), &(BITNUM)); \
785 bmp_iter_next (&(ITER), &(BITNUM)))
786
787/* Loop over all the bits set in BITMAP1 & ~BITMAP2, starting with MIN
788 and setting BITNUM to the bit number. ITER is a bitmap iterator.
789 BITNUM should be treated as a read-only variable as it contains
790 loop state. */
791
792#define EXECUTE_IF_AND_COMPL_IN_BITMAP(BITMAP1, BITMAP2, MIN, BITNUM, ITER) \
793 for (bmp_iter_and_compl_init (&(ITER), (BITMAP1), (BITMAP2), (MIN), \
794 &(BITNUM)); \
795 bmp_iter_and_compl (&(ITER), &(BITNUM)); \
796 bmp_iter_next (&(ITER), &(BITNUM)))
797
798/* A class that ties the lifetime of a bitmap to its scope. */
799class auto_bitmap
800{
801 public:
802 auto_bitmap () { bitmap_initialize (&m_bits, &bitmap_default_obstack); }
803 explicit auto_bitmap (bitmap_obstack *o) { bitmap_initialize (&m_bits, o); }
804 ~auto_bitmap () { bitmap_clear (&m_bits); }
805 // Allow calling bitmap functions on our bitmap.
806 operator bitmap () { return &m_bits; }
807
808 private:
809 // Prevent making a copy that references our bitmap.
810 auto_bitmap (const auto_bitmap &);
811 auto_bitmap &operator = (const auto_bitmap &);
812#if __cplusplus >= 201103L
813 auto_bitmap (auto_bitmap &&);
814 auto_bitmap &operator = (auto_bitmap &&);
815#endif
816
817 bitmap_head m_bits;
818};
819
820#endif /* GCC_BITMAP_H */
821