1 /* Functions to support general ended bitmaps. 2 Copyright (C) 1997-2017 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_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. */ 133 struct 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. */ 189 extern mem_alloc_description<bitmap_usage> bitmap_mem_desc; 190 191 /* Fundamental storage type for bitmap. */ 192 193 typedef 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. */ 209 struct 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. */ 226 227 struct 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. */ 236 237 struct 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 */ 249 extern bitmap_element bitmap_zero_bits; /* Zero bitmap element */ 250 extern bitmap_obstack bitmap_default_obstack; /* Default bitmap obstack */ 251 252 /* Clear a bitmap by freeing up the linked list. */ 253 extern void bitmap_clear (bitmap); 254 255 /* Copy a bitmap to another bitmap. */ 256 extern void bitmap_copy (bitmap, const_bitmap); 257 258 /* Move a bitmap to another bitmap. */ 259 extern void bitmap_move (bitmap, bitmap); 260 261 /* True if two bitmaps are identical. */ 262 extern bool bitmap_equal_p (const_bitmap, const_bitmap); 263 264 /* True if the bitmaps intersect (their AND is non-empty). */ 265 extern 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). */ 269 extern bool bitmap_intersect_compl_p (const_bitmap, const_bitmap); 270 271 /* True if MAP is an empty bitmap. */ 272 inline 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. */ 278 extern bool bitmap_single_bit_set_p (const_bitmap); 279 280 /* Count the number of bits set in the bitmap. */ 281 extern unsigned long bitmap_count_bits (const_bitmap); 282 283 /* Count the number of unique bits set across the two bitmaps. */ 284 extern 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 &, & ~, |, ^. */ 290 extern void bitmap_and (bitmap, const_bitmap, const_bitmap); 291 extern bool bitmap_and_into (bitmap, const_bitmap); 292 extern bool bitmap_and_compl (bitmap, const_bitmap, const_bitmap); 293 extern bool bitmap_and_compl_into (bitmap, const_bitmap); 294 #define bitmap_compl_and(DST, A, B) bitmap_and_compl (DST, B, A) 295 extern void bitmap_compl_and_into (bitmap, const_bitmap); 296 extern void bitmap_clear_range (bitmap, unsigned int, unsigned int); 297 extern void bitmap_set_range (bitmap, unsigned int, unsigned int); 298 extern bool bitmap_ior (bitmap, const_bitmap, const_bitmap); 299 extern bool bitmap_ior_into (bitmap, const_bitmap); 300 extern void bitmap_xor (bitmap, const_bitmap, const_bitmap); 301 extern void bitmap_xor_into (bitmap, const_bitmap); 302 303 /* DST = A | (B & C). Return true if DST changes. */ 304 extern bool bitmap_ior_and_into (bitmap DST, const_bitmap B, const_bitmap C); 305 /* DST = A | (B & ~C). Return true if DST changes. */ 306 extern 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. */ 309 extern 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. */ 313 extern bool bitmap_clear_bit (bitmap, int); 314 315 /* Set a single bit in a bitmap. Return true if the bit changed. */ 316 extern bool bitmap_set_bit (bitmap, int); 317 318 /* Return true if a register is set in a register set. */ 319 extern int bitmap_bit_p (bitmap, int); 320 321 /* Debug functions to print a bitmap linked list. */ 322 extern void debug_bitmap (const_bitmap); 323 extern void debug_bitmap_file (FILE *, const_bitmap); 324 325 /* Print a bitmap. */ 326 extern void bitmap_print (FILE *, const_bitmap, const char *, const char *); 327 328 /* Initialize and release a bitmap obstack. */ 329 extern void bitmap_obstack_initialize (bitmap_obstack *); 330 extern void bitmap_obstack_release (bitmap_obstack *); 331 extern void bitmap_register (bitmap MEM_STAT_DECL); 332 extern 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. */ 336 337 static inline void 338 bitmap_initialize_stat (bitmap head, bitmap_obstack *obstack MEM_STAT_DECL) 339 { 340 head->first = head->current = NULL; 341 head->obstack = obstack; 342 if (GATHER_STATISTICS) 343 bitmap_register (head PASS_MEM_STAT); 344 } 345 #define bitmap_initialize(h,o) bitmap_initialize_stat (h,o MEM_STAT_INFO) 346 347 /* Allocate and free bitmaps from obstack, malloc and gc'd memory. */ 348 extern bitmap bitmap_obstack_alloc_stat (bitmap_obstack *obstack MEM_STAT_DECL); 349 #define bitmap_obstack_alloc(t) bitmap_obstack_alloc_stat (t MEM_STAT_INFO) 350 extern bitmap bitmap_gc_alloc_stat (ALONE_MEM_STAT_DECL); 351 #define bitmap_gc_alloc() bitmap_gc_alloc_stat (ALONE_MEM_STAT_INFO) 352 extern void bitmap_obstack_free (bitmap); 353 354 /* A few compatibility/functions macros for compatibility with sbitmaps */ 355 inline void dump_bitmap (FILE *file, const_bitmap map) 356 { 357 bitmap_print (file, map, "", "\n"); 358 } 359 extern void debug (const bitmap_head &ref); 360 extern void debug (const bitmap_head *ptr); 361 362 extern unsigned bitmap_first_set_bit (const_bitmap); 363 extern unsigned bitmap_last_set_bit (const_bitmap); 364 365 /* Compute bitmap hash (for purposes of hashing etc.) */ 366 extern hashval_t bitmap_hash (const_bitmap); 367 368 /* Allocate a bitmap from a bit obstack. */ 369 #define BITMAP_ALLOC(OBSTACK) bitmap_obstack_alloc (OBSTACK) 370 371 /* Allocate a gc'd bitmap. */ 372 #define BITMAP_GGC_ALLOC() bitmap_gc_alloc () 373 374 /* Do any cleanup needed on a bitmap when it is no longer used. */ 375 #define BITMAP_FREE(BITMAP) \ 376 ((void) (bitmap_obstack_free ((bitmap) BITMAP), (BITMAP) = (bitmap) NULL)) 377 378 /* Iterator for bitmaps. */ 379 380 struct bitmap_iterator 381 { 382 /* Pointer to the current bitmap element. */ 383 bitmap_element *elt1; 384 385 /* Pointer to 2nd bitmap element when two are involved. */ 386 bitmap_element *elt2; 387 388 /* Word within the current element. */ 389 unsigned word_no; 390 391 /* Contents of the actually processed word. When finding next bit 392 it is shifted right, so that the actual bit is always the least 393 significant bit of ACTUAL. */ 394 BITMAP_WORD bits; 395 }; 396 397 /* Initialize a single bitmap iterator. START_BIT is the first bit to 398 iterate from. */ 399 400 static inline void 401 bmp_iter_set_init (bitmap_iterator *bi, const_bitmap map, 402 unsigned start_bit, unsigned *bit_no) 403 { 404 bi->elt1 = map->first; 405 bi->elt2 = NULL; 406 407 /* Advance elt1 until it is not before the block containing start_bit. */ 408 while (1) 409 { 410 if (!bi->elt1) 411 { 412 bi->elt1 = &bitmap_zero_bits; 413 break; 414 } 415 416 if (bi->elt1->indx >= start_bit / BITMAP_ELEMENT_ALL_BITS) 417 break; 418 bi->elt1 = bi->elt1->next; 419 } 420 421 /* We might have gone past the start bit, so reinitialize it. */ 422 if (bi->elt1->indx != start_bit / BITMAP_ELEMENT_ALL_BITS) 423 start_bit = bi->elt1->indx * BITMAP_ELEMENT_ALL_BITS; 424 425 /* Initialize for what is now start_bit. */ 426 bi->word_no = start_bit / BITMAP_WORD_BITS % BITMAP_ELEMENT_WORDS; 427 bi->bits = bi->elt1->bits[bi->word_no]; 428 bi->bits >>= start_bit % BITMAP_WORD_BITS; 429 430 /* If this word is zero, we must make sure we're not pointing at the 431 first bit, otherwise our incrementing to the next word boundary 432 will fail. It won't matter if this increment moves us into the 433 next word. */ 434 start_bit += !bi->bits; 435 436 *bit_no = start_bit; 437 } 438 439 /* Initialize an iterator to iterate over the intersection of two 440 bitmaps. START_BIT is the bit to commence from. */ 441 442 static inline void 443 bmp_iter_and_init (bitmap_iterator *bi, const_bitmap map1, const_bitmap map2, 444 unsigned start_bit, unsigned *bit_no) 445 { 446 bi->elt1 = map1->first; 447 bi->elt2 = map2->first; 448 449 /* Advance elt1 until it is not before the block containing 450 start_bit. */ 451 while (1) 452 { 453 if (!bi->elt1) 454 { 455 bi->elt2 = NULL; 456 break; 457 } 458 459 if (bi->elt1->indx >= start_bit / BITMAP_ELEMENT_ALL_BITS) 460 break; 461 bi->elt1 = bi->elt1->next; 462 } 463 464 /* Advance elt2 until it is not before elt1. */ 465 while (1) 466 { 467 if (!bi->elt2) 468 { 469 bi->elt1 = bi->elt2 = &bitmap_zero_bits; 470 break; 471 } 472 473 if (bi->elt2->indx >= bi->elt1->indx) 474 break; 475 bi->elt2 = bi->elt2->next; 476 } 477 478 /* If we're at the same index, then we have some intersecting bits. */ 479 if (bi->elt1->indx == bi->elt2->indx) 480 { 481 /* We might have advanced beyond the start_bit, so reinitialize 482 for that. */ 483 if (bi->elt1->indx != start_bit / BITMAP_ELEMENT_ALL_BITS) 484 start_bit = bi->elt1->indx * BITMAP_ELEMENT_ALL_BITS; 485 486 bi->word_no = start_bit / BITMAP_WORD_BITS % BITMAP_ELEMENT_WORDS; 487 bi->bits = bi->elt1->bits[bi->word_no] & bi->elt2->bits[bi->word_no]; 488 bi->bits >>= start_bit % BITMAP_WORD_BITS; 489 } 490 else 491 { 492 /* Otherwise we must immediately advance elt1, so initialize for 493 that. */ 494 bi->word_no = BITMAP_ELEMENT_WORDS - 1; 495 bi->bits = 0; 496 } 497 498 /* If this word is zero, we must make sure we're not pointing at the 499 first bit, otherwise our incrementing to the next word boundary 500 will fail. It won't matter if this increment moves us into the 501 next word. */ 502 start_bit += !bi->bits; 503 504 *bit_no = start_bit; 505 } 506 507 /* Initialize an iterator to iterate over the bits in MAP1 & ~MAP2. 508 */ 509 510 static inline void 511 bmp_iter_and_compl_init (bitmap_iterator *bi, 512 const_bitmap map1, const_bitmap map2, 513 unsigned start_bit, unsigned *bit_no) 514 { 515 bi->elt1 = map1->first; 516 bi->elt2 = map2->first; 517 518 /* Advance elt1 until it is not before the block containing start_bit. */ 519 while (1) 520 { 521 if (!bi->elt1) 522 { 523 bi->elt1 = &bitmap_zero_bits; 524 break; 525 } 526 527 if (bi->elt1->indx >= start_bit / BITMAP_ELEMENT_ALL_BITS) 528 break; 529 bi->elt1 = bi->elt1->next; 530 } 531 532 /* Advance elt2 until it is not before elt1. */ 533 while (bi->elt2 && bi->elt2->indx < bi->elt1->indx) 534 bi->elt2 = bi->elt2->next; 535 536 /* We might have advanced beyond the start_bit, so reinitialize for 537 that. */ 538 if (bi->elt1->indx != start_bit / BITMAP_ELEMENT_ALL_BITS) 539 start_bit = bi->elt1->indx * BITMAP_ELEMENT_ALL_BITS; 540 541 bi->word_no = start_bit / BITMAP_WORD_BITS % BITMAP_ELEMENT_WORDS; 542 bi->bits = bi->elt1->bits[bi->word_no]; 543 if (bi->elt2 && bi->elt1->indx == bi->elt2->indx) 544 bi->bits &= ~bi->elt2->bits[bi->word_no]; 545 bi->bits >>= start_bit % BITMAP_WORD_BITS; 546 547 /* If this word is zero, we must make sure we're not pointing at the 548 first bit, otherwise our incrementing to the next word boundary 549 will fail. It won't matter if this increment moves us into the 550 next word. */ 551 start_bit += !bi->bits; 552 553 *bit_no = start_bit; 554 } 555 556 /* Advance to the next bit in BI. We don't advance to the next 557 nonzero bit yet. */ 558 559 static inline void 560 bmp_iter_next (bitmap_iterator *bi, unsigned *bit_no) 561 { 562 bi->bits >>= 1; 563 *bit_no += 1; 564 } 565 566 /* Advance to first set bit in BI. */ 567 568 static inline void 569 bmp_iter_next_bit (bitmap_iterator * bi, unsigned *bit_no) 570 { 571 #if (GCC_VERSION >= 3004) 572 { 573 unsigned int n = __builtin_ctzl (bi->bits); 574 gcc_assert (sizeof (unsigned long) == sizeof (BITMAP_WORD)); 575 bi->bits >>= n; 576 *bit_no += n; 577 } 578 #else 579 while (!(bi->bits & 1)) 580 { 581 bi->bits >>= 1; 582 *bit_no += 1; 583 } 584 #endif 585 } 586 587 /* Advance to the next nonzero bit of a single bitmap, we will have 588 already advanced past the just iterated bit. Return true if there 589 is a bit to iterate. */ 590 591 static inline bool 592 bmp_iter_set (bitmap_iterator *bi, unsigned *bit_no) 593 { 594 /* If our current word is nonzero, it contains the bit we want. */ 595 if (bi->bits) 596 { 597 next_bit: 598 bmp_iter_next_bit (bi, bit_no); 599 return true; 600 } 601 602 /* Round up to the word boundary. We might have just iterated past 603 the end of the last word, hence the -1. It is not possible for 604 bit_no to point at the beginning of the now last word. */ 605 *bit_no = ((*bit_no + BITMAP_WORD_BITS - 1) 606 / BITMAP_WORD_BITS * BITMAP_WORD_BITS); 607 bi->word_no++; 608 609 while (1) 610 { 611 /* Find the next nonzero word in this elt. */ 612 while (bi->word_no != BITMAP_ELEMENT_WORDS) 613 { 614 bi->bits = bi->elt1->bits[bi->word_no]; 615 if (bi->bits) 616 goto next_bit; 617 *bit_no += BITMAP_WORD_BITS; 618 bi->word_no++; 619 } 620 621 /* Make sure we didn't remove the element while iterating. */ 622 gcc_checking_assert (bi->elt1->indx != -1U); 623 624 /* Advance to the next element. */ 625 bi->elt1 = bi->elt1->next; 626 if (!bi->elt1) 627 return false; 628 *bit_no = bi->elt1->indx * BITMAP_ELEMENT_ALL_BITS; 629 bi->word_no = 0; 630 } 631 } 632 633 /* Advance to the next nonzero bit of an intersecting pair of 634 bitmaps. We will have already advanced past the just iterated bit. 635 Return true if there is a bit to iterate. */ 636 637 static inline bool 638 bmp_iter_and (bitmap_iterator *bi, unsigned *bit_no) 639 { 640 /* If our current word is nonzero, it contains the bit we want. */ 641 if (bi->bits) 642 { 643 next_bit: 644 bmp_iter_next_bit (bi, bit_no); 645 return true; 646 } 647 648 /* Round up to the word boundary. We might have just iterated past 649 the end of the last word, hence the -1. It is not possible for 650 bit_no to point at the beginning of the now last word. */ 651 *bit_no = ((*bit_no + BITMAP_WORD_BITS - 1) 652 / BITMAP_WORD_BITS * BITMAP_WORD_BITS); 653 bi->word_no++; 654 655 while (1) 656 { 657 /* Find the next nonzero word in this elt. */ 658 while (bi->word_no != BITMAP_ELEMENT_WORDS) 659 { 660 bi->bits = bi->elt1->bits[bi->word_no] & bi->elt2->bits[bi->word_no]; 661 if (bi->bits) 662 goto next_bit; 663 *bit_no += BITMAP_WORD_BITS; 664 bi->word_no++; 665 } 666 667 /* Advance to the next identical element. */ 668 do 669 { 670 /* Make sure we didn't remove the element while iterating. */ 671 gcc_checking_assert (bi->elt1->indx != -1U); 672 673 /* Advance elt1 while it is less than elt2. We always want 674 to advance one elt. */ 675 do 676 { 677 bi->elt1 = bi->elt1->next; 678 if (!bi->elt1) 679 return false; 680 } 681 while (bi->elt1->indx < bi->elt2->indx); 682 683 /* Make sure we didn't remove the element while iterating. */ 684 gcc_checking_assert (bi->elt2->indx != -1U); 685 686 /* Advance elt2 to be no less than elt1. This might not 687 advance. */ 688 while (bi->elt2->indx < bi->elt1->indx) 689 { 690 bi->elt2 = bi->elt2->next; 691 if (!bi->elt2) 692 return false; 693 } 694 } 695 while (bi->elt1->indx != bi->elt2->indx); 696 697 *bit_no = bi->elt1->indx * BITMAP_ELEMENT_ALL_BITS; 698 bi->word_no = 0; 699 } 700 } 701 702 /* Advance to the next nonzero bit in the intersection of 703 complemented bitmaps. We will have already advanced past the just 704 iterated bit. */ 705 706 static inline bool 707 bmp_iter_and_compl (bitmap_iterator *bi, unsigned *bit_no) 708 { 709 /* If our current word is nonzero, it contains the bit we want. */ 710 if (bi->bits) 711 { 712 next_bit: 713 bmp_iter_next_bit (bi, bit_no); 714 return true; 715 } 716 717 /* Round up to the word boundary. We might have just iterated past 718 the end of the last word, hence the -1. It is not possible for 719 bit_no to point at the beginning of the now last word. */ 720 *bit_no = ((*bit_no + BITMAP_WORD_BITS - 1) 721 / BITMAP_WORD_BITS * BITMAP_WORD_BITS); 722 bi->word_no++; 723 724 while (1) 725 { 726 /* Find the next nonzero word in this elt. */ 727 while (bi->word_no != BITMAP_ELEMENT_WORDS) 728 { 729 bi->bits = bi->elt1->bits[bi->word_no]; 730 if (bi->elt2 && bi->elt2->indx == bi->elt1->indx) 731 bi->bits &= ~bi->elt2->bits[bi->word_no]; 732 if (bi->bits) 733 goto next_bit; 734 *bit_no += BITMAP_WORD_BITS; 735 bi->word_no++; 736 } 737 738 /* Make sure we didn't remove the element while iterating. */ 739 gcc_checking_assert (bi->elt1->indx != -1U); 740 741 /* Advance to the next element of elt1. */ 742 bi->elt1 = bi->elt1->next; 743 if (!bi->elt1) 744 return false; 745 746 /* Make sure we didn't remove the element while iterating. */ 747 gcc_checking_assert (! bi->elt2 || bi->elt2->indx != -1U); 748 749 /* Advance elt2 until it is no less than elt1. */ 750 while (bi->elt2 && bi->elt2->indx < bi->elt1->indx) 751 bi->elt2 = bi->elt2->next; 752 753 *bit_no = bi->elt1->indx * BITMAP_ELEMENT_ALL_BITS; 754 bi->word_no = 0; 755 } 756 } 757 758 /* If you are modifying a bitmap you are currently iterating over you 759 have to ensure to 760 - never remove the current bit; 761 - if you set or clear a bit before the current bit this operation 762 will not affect the set of bits you are visiting during the iteration; 763 - if you set or clear a bit after the current bit it is unspecified 764 whether that affects the set of bits you are visiting during the 765 iteration. 766 If you want to remove the current bit you can delay this to the next 767 iteration (and after the iteration in case the last iteration is 768 affected). */ 769 770 /* Loop over all bits set in BITMAP, starting with MIN and setting 771 BITNUM to the bit number. ITER is a bitmap iterator. BITNUM 772 should be treated as a read-only variable as it contains loop 773 state. */ 774 775 #ifndef EXECUTE_IF_SET_IN_BITMAP 776 /* See sbitmap.h for the other definition of EXECUTE_IF_SET_IN_BITMAP. */ 777 #define EXECUTE_IF_SET_IN_BITMAP(BITMAP, MIN, BITNUM, ITER) \ 778 for (bmp_iter_set_init (&(ITER), (BITMAP), (MIN), &(BITNUM)); \ 779 bmp_iter_set (&(ITER), &(BITNUM)); \ 780 bmp_iter_next (&(ITER), &(BITNUM))) 781 #endif 782 783 /* Loop over all the bits set in BITMAP1 & BITMAP2, starting with MIN 784 and setting BITNUM to the bit number. ITER is a bitmap iterator. 785 BITNUM should be treated as a read-only variable as it contains 786 loop state. */ 787 788 #define EXECUTE_IF_AND_IN_BITMAP(BITMAP1, BITMAP2, MIN, BITNUM, ITER) \ 789 for (bmp_iter_and_init (&(ITER), (BITMAP1), (BITMAP2), (MIN), \ 790 &(BITNUM)); \ 791 bmp_iter_and (&(ITER), &(BITNUM)); \ 792 bmp_iter_next (&(ITER), &(BITNUM))) 793 794 /* Loop over all the bits set in BITMAP1 & ~BITMAP2, starting with MIN 795 and setting BITNUM to the bit number. ITER is a bitmap iterator. 796 BITNUM should be treated as a read-only variable as it contains 797 loop state. */ 798 799 #define EXECUTE_IF_AND_COMPL_IN_BITMAP(BITMAP1, BITMAP2, MIN, BITNUM, ITER) \ 800 for (bmp_iter_and_compl_init (&(ITER), (BITMAP1), (BITMAP2), (MIN), \ 801 &(BITNUM)); \ 802 bmp_iter_and_compl (&(ITER), &(BITNUM)); \ 803 bmp_iter_next (&(ITER), &(BITNUM))) 804 805 /* A class that ties the lifetime of a bitmap to its scope. */ 806 class auto_bitmap 807 { 808 public: 809 auto_bitmap () { bits = BITMAP_ALLOC (NULL); } 810 ~auto_bitmap () { BITMAP_FREE (bits); } 811 // Allow calling bitmap functions on our bitmap. 812 operator bitmap () { return bits; } 813 814 private: 815 // Prevent making a copy that references our bitmap. 816 auto_bitmap (const auto_bitmap &); 817 auto_bitmap &operator = (const auto_bitmap &); 818 #if __cplusplus >= 201103L 819 auto_bitmap (auto_bitmap &&); 820 auto_bitmap &operator = (auto_bitmap &&); 821 #endif 822 823 bitmap bits; 824 }; 825 826 #endif /* GCC_BITMAP_H */ 827