1 /* Functions to support general ended bitmaps. 2 Copyright (C) 1997-2018 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 (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. */ 347 extern bitmap bitmap_alloc (bitmap_obstack *obstack CXX_MEM_STAT_INFO); 348 #define BITMAP_ALLOC bitmap_alloc 349 extern bitmap bitmap_gc_alloc (ALONE_CXX_MEM_STAT_INFO); 350 #define BITMAP_GGC_ALLOC bitmap_gc_alloc 351 extern void bitmap_obstack_free (bitmap); 352 353 /* A few compatibility/functions macros for compatibility with sbitmaps */ 354 inline void dump_bitmap (FILE *file, const_bitmap map) 355 { 356 bitmap_print (file, map, "", "\n"); 357 } 358 extern void debug (const bitmap_head &ref); 359 extern void debug (const bitmap_head *ptr); 360 361 extern unsigned bitmap_first_set_bit (const_bitmap); 362 extern unsigned bitmap_last_set_bit (const_bitmap); 363 364 /* Compute bitmap hash (for purposes of hashing etc.) */ 365 extern 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. */ 372 373 struct 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. */ 392 393 static inline void 394 bmp_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. */ 434 435 static inline void 436 bmp_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 */ 502 503 static inline void 504 bmp_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. */ 551 552 static inline void 553 bmp_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. */ 560 561 static inline void 562 bmp_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. */ 583 584 static inline bool 585 bmp_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. */ 629 630 static inline bool 631 bmp_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. */ 698 699 static inline bool 700 bmp_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. */ 799 class 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