1 /* SEC_MERGE support. 2 Copyright (C) 2001-2022 Free Software Foundation, Inc. 3 Written by Jakub Jelinek <jakub@redhat.com>. 4 5 This file is part of BFD, the Binary File Descriptor library. 6 7 This program is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 3 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program; if not, write to the Free Software 19 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, 20 MA 02110-1301, USA. */ 21 22 23 /* This file contains support for merging duplicate entities within sections, 24 as used in ELF SHF_MERGE. */ 25 26 #include "sysdep.h" 27 #include <limits.h> 28 #include "bfd.h" 29 #include "elf-bfd.h" 30 #include "libbfd.h" 31 #include "hashtab.h" 32 #include "libiberty.h" 33 34 struct sec_merge_sec_info; 35 36 /* An entry in the section merge hash table. */ 37 38 struct sec_merge_hash_entry 39 { 40 struct bfd_hash_entry root; 41 /* Length of this entry. This includes the zero terminator. */ 42 unsigned int len; 43 /* Start of this string needs to be aligned to 44 alignment octets (not 1 << align). */ 45 unsigned int alignment; 46 union 47 { 48 /* Index within the merged section. */ 49 bfd_size_type index; 50 /* Entry this is a suffix of (if alignment is 0). */ 51 struct sec_merge_hash_entry *suffix; 52 } u; 53 /* Which section is it in. */ 54 struct sec_merge_sec_info *secinfo; 55 /* Next entity in the hash table. */ 56 struct sec_merge_hash_entry *next; 57 }; 58 59 /* The section merge hash table. */ 60 61 struct sec_merge_hash 62 { 63 struct bfd_hash_table table; 64 /* Next available index. */ 65 bfd_size_type size; 66 /* First entity in the SEC_MERGE sections of this type. */ 67 struct sec_merge_hash_entry *first; 68 /* Last entity in the SEC_MERGE sections of this type. */ 69 struct sec_merge_hash_entry *last; 70 /* Entity size. */ 71 unsigned int entsize; 72 /* Are entries fixed size or zero terminated strings? */ 73 bool strings; 74 }; 75 76 struct sec_merge_info 77 { 78 /* Chain of sec_merge_infos. */ 79 struct sec_merge_info *next; 80 /* Chain of sec_merge_sec_infos. */ 81 struct sec_merge_sec_info *chain; 82 /* A hash table used to hold section content. */ 83 struct sec_merge_hash *htab; 84 }; 85 86 struct sec_merge_sec_info 87 { 88 /* Chain of sec_merge_sec_infos. */ 89 struct sec_merge_sec_info *next; 90 /* The corresponding section. */ 91 asection *sec; 92 /* Pointer to merge_info pointing to us. */ 93 void **psecinfo; 94 /* A hash table used to hold section content. */ 95 struct sec_merge_hash *htab; 96 /* First string in this section. */ 97 struct sec_merge_hash_entry *first_str; 98 /* Original section content. */ 99 unsigned char contents[1]; 100 }; 101 102 103 /* Routine to create an entry in a section merge hashtab. */ 104 105 static struct bfd_hash_entry * 106 sec_merge_hash_newfunc (struct bfd_hash_entry *entry, 107 struct bfd_hash_table *table, const char *string) 108 { 109 /* Allocate the structure if it has not already been allocated by a 110 subclass. */ 111 if (entry == NULL) 112 entry = (struct bfd_hash_entry *) 113 bfd_hash_allocate (table, sizeof (struct sec_merge_hash_entry)); 114 if (entry == NULL) 115 return NULL; 116 117 /* Call the allocation method of the superclass. */ 118 entry = bfd_hash_newfunc (entry, table, string); 119 120 if (entry != NULL) 121 { 122 /* Initialize the local fields. */ 123 struct sec_merge_hash_entry *ret = (struct sec_merge_hash_entry *) entry; 124 125 ret->u.suffix = NULL; 126 ret->alignment = 0; 127 ret->secinfo = NULL; 128 ret->next = NULL; 129 } 130 131 return entry; 132 } 133 134 /* Look up an entry in a section merge hash table. */ 135 136 static struct sec_merge_hash_entry * 137 sec_merge_hash_lookup (struct sec_merge_hash *table, const char *string, 138 unsigned int alignment, bool create) 139 { 140 const unsigned char *s; 141 unsigned long hash; 142 unsigned int c; 143 struct sec_merge_hash_entry *hashp; 144 unsigned int len, i; 145 unsigned int _index; 146 147 hash = 0; 148 len = 0; 149 s = (const unsigned char *) string; 150 if (table->strings) 151 { 152 if (table->entsize == 1) 153 { 154 while ((c = *s++) != '\0') 155 { 156 hash += c + (c << 17); 157 hash ^= hash >> 2; 158 ++len; 159 } 160 hash += len + (len << 17); 161 } 162 else 163 { 164 for (;;) 165 { 166 for (i = 0; i < table->entsize; ++i) 167 if (s[i] != '\0') 168 break; 169 if (i == table->entsize) 170 break; 171 for (i = 0; i < table->entsize; ++i) 172 { 173 c = *s++; 174 hash += c + (c << 17); 175 hash ^= hash >> 2; 176 } 177 ++len; 178 } 179 hash += len + (len << 17); 180 len *= table->entsize; 181 } 182 hash ^= hash >> 2; 183 len += table->entsize; 184 } 185 else 186 { 187 for (i = 0; i < table->entsize; ++i) 188 { 189 c = *s++; 190 hash += c + (c << 17); 191 hash ^= hash >> 2; 192 } 193 len = table->entsize; 194 } 195 196 _index = hash % table->table.size; 197 for (hashp = (struct sec_merge_hash_entry *) table->table.table[_index]; 198 hashp != NULL; 199 hashp = (struct sec_merge_hash_entry *) hashp->root.next) 200 { 201 if (hashp->root.hash == hash 202 && len == hashp->len 203 && memcmp (hashp->root.string, string, len) == 0) 204 { 205 /* If the string we found does not have at least the required 206 alignment, we need to insert another copy. */ 207 if (hashp->alignment < alignment) 208 { 209 if (create) 210 { 211 /* Mark the less aligned copy as deleted. */ 212 hashp->len = 0; 213 hashp->alignment = 0; 214 } 215 break; 216 } 217 return hashp; 218 } 219 } 220 221 if (! create) 222 return NULL; 223 224 hashp = ((struct sec_merge_hash_entry *) 225 bfd_hash_insert (&table->table, string, hash)); 226 if (hashp == NULL) 227 return NULL; 228 hashp->len = len; 229 hashp->alignment = alignment; 230 return hashp; 231 } 232 233 /* Create a new hash table. */ 234 235 static struct sec_merge_hash * 236 sec_merge_init (unsigned int entsize, bool strings) 237 { 238 struct sec_merge_hash *table; 239 240 table = (struct sec_merge_hash *) bfd_malloc (sizeof (struct sec_merge_hash)); 241 if (table == NULL) 242 return NULL; 243 244 if (! bfd_hash_table_init_n (&table->table, sec_merge_hash_newfunc, 245 sizeof (struct sec_merge_hash_entry), 16699)) 246 { 247 free (table); 248 return NULL; 249 } 250 251 table->size = 0; 252 table->first = NULL; 253 table->last = NULL; 254 table->entsize = entsize; 255 table->strings = strings; 256 257 return table; 258 } 259 260 /* Get the index of an entity in a hash table, adding it if it is not 261 already present. */ 262 263 static struct sec_merge_hash_entry * 264 sec_merge_add (struct sec_merge_hash *tab, const char *str, 265 unsigned int alignment, struct sec_merge_sec_info *secinfo) 266 { 267 struct sec_merge_hash_entry *entry; 268 269 entry = sec_merge_hash_lookup (tab, str, alignment, true); 270 if (entry == NULL) 271 return NULL; 272 273 if (entry->secinfo == NULL) 274 { 275 tab->size++; 276 entry->secinfo = secinfo; 277 if (tab->first == NULL) 278 tab->first = entry; 279 else 280 tab->last->next = entry; 281 tab->last = entry; 282 } 283 284 return entry; 285 } 286 287 static bool 288 sec_merge_emit (bfd *abfd, struct sec_merge_hash_entry *entry, 289 unsigned char *contents, file_ptr offset) 290 { 291 struct sec_merge_sec_info *secinfo = entry->secinfo; 292 asection *sec = secinfo->sec; 293 char *pad = NULL; 294 bfd_size_type off = 0; 295 unsigned int opb = bfd_octets_per_byte (abfd, sec); 296 int alignment_power = sec->output_section->alignment_power * opb; 297 bfd_size_type pad_len; /* Octets. */ 298 299 /* FIXME: If alignment_power is 0 then really we should scan the 300 entry list for the largest required alignment and use that. */ 301 pad_len = alignment_power ? ((bfd_size_type) 1 << alignment_power) : 16; 302 303 pad = (char *) bfd_zmalloc (pad_len); 304 if (pad == NULL) 305 return false; 306 307 for (; entry != NULL && entry->secinfo == secinfo; entry = entry->next) 308 { 309 const char *str; 310 bfd_size_type len; 311 312 len = -off & (entry->alignment - 1); 313 if (len != 0) 314 { 315 BFD_ASSERT (len <= pad_len); 316 if (contents) 317 { 318 memcpy (contents + offset, pad, len); 319 offset += len; 320 } 321 else if (bfd_bwrite (pad, len, abfd) != len) 322 goto err; 323 off += len; 324 } 325 326 str = entry->root.string; 327 len = entry->len; 328 329 if (contents) 330 { 331 memcpy (contents + offset, str, len); 332 offset += len; 333 } 334 else if (bfd_bwrite (str, len, abfd) != len) 335 goto err; 336 337 off += len; 338 } 339 340 /* Trailing alignment needed? */ 341 off = sec->size - off; 342 if (off != 0) 343 { 344 BFD_ASSERT (off <= pad_len); 345 if (contents) 346 memcpy (contents + offset, pad, off); 347 else if (bfd_bwrite (pad, off, abfd) != off) 348 goto err; 349 } 350 351 free (pad); 352 return true; 353 354 err: 355 free (pad); 356 return false; 357 } 358 359 /* Register a SEC_MERGE section as a candidate for merging. 360 This function is called for all non-dynamic SEC_MERGE input sections. */ 361 362 bool 363 _bfd_add_merge_section (bfd *abfd, void **psinfo, asection *sec, 364 void **psecinfo) 365 { 366 struct sec_merge_info *sinfo; 367 struct sec_merge_sec_info *secinfo; 368 unsigned int alignment_power; /* Octets. */ 369 unsigned int align; /* Octets. */ 370 bfd_size_type amt; 371 bfd_byte *contents; 372 unsigned int opb = bfd_octets_per_byte (abfd, sec); 373 374 if ((abfd->flags & DYNAMIC) != 0 375 || (sec->flags & SEC_MERGE) == 0) 376 abort (); 377 378 if (sec->size == 0 379 || (sec->flags & SEC_EXCLUDE) != 0 380 || sec->entsize == 0) 381 return true; 382 383 if (sec->size % sec->entsize != 0) 384 return true; 385 386 if ((sec->flags & SEC_RELOC) != 0) 387 { 388 /* We aren't prepared to handle relocations in merged sections. */ 389 return true; 390 } 391 392 #ifndef CHAR_BIT 393 #define CHAR_BIT 8 394 #endif 395 alignment_power = sec->alignment_power * opb; 396 if (alignment_power >= sizeof (align) * CHAR_BIT) 397 return true; 398 399 align = 1u << alignment_power; 400 if ((sec->entsize < align 401 && ((sec->entsize & (sec->entsize - 1)) 402 || !(sec->flags & SEC_STRINGS))) 403 || (sec->entsize > align 404 && (sec->entsize & (align - 1)))) 405 { 406 /* Sanity check. If string character size is smaller than 407 alignment, then we require character size to be a power 408 of 2, otherwise character size must be integer multiple 409 of alignment. For non-string constants, alignment must 410 be smaller than or equal to entity size and entity size 411 must be integer multiple of alignment. */ 412 return true; 413 } 414 415 for (sinfo = (struct sec_merge_info *) *psinfo; sinfo; sinfo = sinfo->next) 416 if ((secinfo = sinfo->chain) 417 && ! ((secinfo->sec->flags ^ sec->flags) & (SEC_MERGE | SEC_STRINGS)) 418 && secinfo->sec->entsize == sec->entsize 419 && secinfo->sec->alignment_power == sec->alignment_power 420 && secinfo->sec->output_section == sec->output_section) 421 break; 422 423 if (sinfo == NULL) 424 { 425 /* Initialize the information we need to keep track of. */ 426 sinfo = (struct sec_merge_info *) 427 bfd_alloc (abfd, sizeof (struct sec_merge_info)); 428 if (sinfo == NULL) 429 goto error_return; 430 sinfo->next = (struct sec_merge_info *) *psinfo; 431 sinfo->chain = NULL; 432 *psinfo = sinfo; 433 sinfo->htab = sec_merge_init (sec->entsize, (sec->flags & SEC_STRINGS)); 434 if (sinfo->htab == NULL) 435 goto error_return; 436 } 437 438 /* Read the section from abfd. */ 439 440 amt = sizeof (struct sec_merge_sec_info) - 1 + sec->size; 441 if (sec->flags & SEC_STRINGS) 442 /* Some versions of gcc may emit a string without a zero terminator. 443 See http://gcc.gnu.org/ml/gcc-patches/2006-06/msg01004.html 444 Allocate space for an extra zero. */ 445 amt += sec->entsize; 446 *psecinfo = bfd_alloc (abfd, amt); 447 if (*psecinfo == NULL) 448 goto error_return; 449 450 secinfo = (struct sec_merge_sec_info *) *psecinfo; 451 if (sinfo->chain) 452 { 453 secinfo->next = sinfo->chain->next; 454 sinfo->chain->next = secinfo; 455 } 456 else 457 secinfo->next = secinfo; 458 sinfo->chain = secinfo; 459 secinfo->sec = sec; 460 secinfo->psecinfo = psecinfo; 461 secinfo->htab = sinfo->htab; 462 secinfo->first_str = NULL; 463 464 sec->rawsize = sec->size; 465 if (sec->flags & SEC_STRINGS) 466 memset (secinfo->contents + sec->size, 0, sec->entsize); 467 contents = secinfo->contents; 468 if (! bfd_get_full_section_contents (sec->owner, sec, &contents)) 469 goto error_return; 470 471 return true; 472 473 error_return: 474 *psecinfo = NULL; 475 return false; 476 } 477 478 /* Record one section into the hash table. */ 479 static bool 480 record_section (struct sec_merge_info *sinfo, 481 struct sec_merge_sec_info *secinfo) 482 { 483 asection *sec = secinfo->sec; 484 struct sec_merge_hash_entry *entry; 485 bool nul; 486 unsigned char *p, *end; 487 bfd_vma mask, eltalign; 488 unsigned int align, i; 489 490 align = sec->alignment_power; 491 end = secinfo->contents + sec->size; 492 nul = false; 493 mask = ((bfd_vma) 1 << align) - 1; 494 if (sec->flags & SEC_STRINGS) 495 { 496 for (p = secinfo->contents; p < end; ) 497 { 498 eltalign = p - secinfo->contents; 499 eltalign = ((eltalign ^ (eltalign - 1)) + 1) >> 1; 500 if (!eltalign || eltalign > mask) 501 eltalign = mask + 1; 502 entry = sec_merge_add (sinfo->htab, (char *) p, (unsigned) eltalign, 503 secinfo); 504 if (! entry) 505 goto error_return; 506 p += entry->len; 507 if (sec->entsize == 1) 508 { 509 while (p < end && *p == 0) 510 { 511 if (!nul && !((p - secinfo->contents) & mask)) 512 { 513 nul = true; 514 entry = sec_merge_add (sinfo->htab, "", 515 (unsigned) mask + 1, secinfo); 516 if (! entry) 517 goto error_return; 518 } 519 p++; 520 } 521 } 522 else 523 { 524 while (p < end) 525 { 526 for (i = 0; i < sec->entsize; i++) 527 if (p[i] != '\0') 528 break; 529 if (i != sec->entsize) 530 break; 531 if (!nul && !((p - secinfo->contents) & mask)) 532 { 533 nul = true; 534 entry = sec_merge_add (sinfo->htab, (char *) p, 535 (unsigned) mask + 1, secinfo); 536 if (! entry) 537 goto error_return; 538 } 539 p += sec->entsize; 540 } 541 } 542 } 543 } 544 else 545 { 546 for (p = secinfo->contents; p < end; p += sec->entsize) 547 { 548 entry = sec_merge_add (sinfo->htab, (char *) p, 1, secinfo); 549 if (! entry) 550 goto error_return; 551 } 552 } 553 554 return true; 555 556 error_return: 557 for (secinfo = sinfo->chain; secinfo; secinfo = secinfo->next) 558 *secinfo->psecinfo = NULL; 559 return false; 560 } 561 562 /* qsort comparison function. Won't ever return zero as all entries 563 differ, so there is no issue with qsort stability here. */ 564 565 static int 566 strrevcmp (const void *a, const void *b) 567 { 568 struct sec_merge_hash_entry *A = *(struct sec_merge_hash_entry **) a; 569 struct sec_merge_hash_entry *B = *(struct sec_merge_hash_entry **) b; 570 unsigned int lenA = A->len; 571 unsigned int lenB = B->len; 572 const unsigned char *s = (const unsigned char *) A->root.string + lenA - 1; 573 const unsigned char *t = (const unsigned char *) B->root.string + lenB - 1; 574 int l = lenA < lenB ? lenA : lenB; 575 576 while (l) 577 { 578 if (*s != *t) 579 return (int) *s - (int) *t; 580 s--; 581 t--; 582 l--; 583 } 584 return lenA - lenB; 585 } 586 587 /* Like strrevcmp, but for the case where all strings have the same 588 alignment > entsize. */ 589 590 static int 591 strrevcmp_align (const void *a, const void *b) 592 { 593 struct sec_merge_hash_entry *A = *(struct sec_merge_hash_entry **) a; 594 struct sec_merge_hash_entry *B = *(struct sec_merge_hash_entry **) b; 595 unsigned int lenA = A->len; 596 unsigned int lenB = B->len; 597 const unsigned char *s = (const unsigned char *) A->root.string + lenA - 1; 598 const unsigned char *t = (const unsigned char *) B->root.string + lenB - 1; 599 int l = lenA < lenB ? lenA : lenB; 600 int tail_align = (lenA & (A->alignment - 1)) - (lenB & (A->alignment - 1)); 601 602 if (tail_align != 0) 603 return tail_align; 604 605 while (l) 606 { 607 if (*s != *t) 608 return (int) *s - (int) *t; 609 s--; 610 t--; 611 l--; 612 } 613 return lenA - lenB; 614 } 615 616 static inline int 617 is_suffix (const struct sec_merge_hash_entry *A, 618 const struct sec_merge_hash_entry *B) 619 { 620 if (A->len <= B->len) 621 /* B cannot be a suffix of A unless A is equal to B, which is guaranteed 622 not to be equal by the hash table. */ 623 return 0; 624 625 return memcmp (A->root.string + (A->len - B->len), 626 B->root.string, B->len) == 0; 627 } 628 629 /* This is a helper function for _bfd_merge_sections. It attempts to 630 merge strings matching suffixes of longer strings. */ 631 static struct sec_merge_sec_info * 632 merge_strings (struct sec_merge_info *sinfo) 633 { 634 struct sec_merge_hash_entry **array, **a, *e; 635 struct sec_merge_sec_info *secinfo; 636 bfd_size_type size, amt; 637 unsigned int alignment = 0; 638 639 /* Now sort the strings */ 640 amt = sinfo->htab->size * sizeof (struct sec_merge_hash_entry *); 641 array = (struct sec_merge_hash_entry **) bfd_malloc (amt); 642 if (array == NULL) 643 return NULL; 644 645 for (e = sinfo->htab->first, a = array; e; e = e->next) 646 if (e->alignment) 647 { 648 *a++ = e; 649 /* Adjust the length to not include the zero terminator. */ 650 e->len -= sinfo->htab->entsize; 651 if (alignment != e->alignment) 652 { 653 if (alignment == 0) 654 alignment = e->alignment; 655 else 656 alignment = (unsigned) -1; 657 } 658 } 659 660 sinfo->htab->size = a - array; 661 if (sinfo->htab->size != 0) 662 { 663 qsort (array, (size_t) sinfo->htab->size, 664 sizeof (struct sec_merge_hash_entry *), 665 (alignment != (unsigned) -1 && alignment > sinfo->htab->entsize 666 ? strrevcmp_align : strrevcmp)); 667 668 /* Loop over the sorted array and merge suffixes */ 669 e = *--a; 670 e->len += sinfo->htab->entsize; 671 while (--a >= array) 672 { 673 struct sec_merge_hash_entry *cmp = *a; 674 675 cmp->len += sinfo->htab->entsize; 676 if (e->alignment >= cmp->alignment 677 && !((e->len - cmp->len) & (cmp->alignment - 1)) 678 && is_suffix (e, cmp)) 679 { 680 cmp->u.suffix = e; 681 cmp->alignment = 0; 682 } 683 else 684 e = cmp; 685 } 686 } 687 688 free (array); 689 690 /* Now assign positions to the strings we want to keep. */ 691 size = 0; 692 secinfo = sinfo->htab->first->secinfo; 693 for (e = sinfo->htab->first; e; e = e->next) 694 { 695 if (e->secinfo != secinfo) 696 { 697 secinfo->sec->size = size; 698 secinfo = e->secinfo; 699 } 700 if (e->alignment) 701 { 702 if (e->secinfo->first_str == NULL) 703 { 704 e->secinfo->first_str = e; 705 size = 0; 706 } 707 size = (size + e->alignment - 1) & ~((bfd_vma) e->alignment - 1); 708 e->u.index = size; 709 size += e->len; 710 } 711 } 712 secinfo->sec->size = size; 713 714 /* And now adjust the rest, removing them from the chain (but not hashtable) 715 at the same time. */ 716 for (a = &sinfo->htab->first, e = *a; e; e = e->next) 717 if (e->alignment) 718 a = &e->next; 719 else 720 { 721 *a = e->next; 722 if (e->len) 723 { 724 e->secinfo = e->u.suffix->secinfo; 725 e->alignment = e->u.suffix->alignment; 726 e->u.index = e->u.suffix->u.index + (e->u.suffix->len - e->len); 727 } 728 } 729 return secinfo; 730 } 731 732 /* This function is called once after all SEC_MERGE sections are registered 733 with _bfd_merge_section. */ 734 735 bool 736 _bfd_merge_sections (bfd *abfd, 737 struct bfd_link_info *info ATTRIBUTE_UNUSED, 738 void *xsinfo, 739 void (*remove_hook) (bfd *, asection *)) 740 { 741 struct sec_merge_info *sinfo; 742 743 for (sinfo = (struct sec_merge_info *) xsinfo; sinfo; sinfo = sinfo->next) 744 { 745 struct sec_merge_sec_info *secinfo; 746 bfd_size_type align; /* Bytes. */ 747 748 if (! sinfo->chain) 749 continue; 750 751 /* Move sinfo->chain to head of the chain, terminate it. */ 752 secinfo = sinfo->chain; 753 sinfo->chain = secinfo->next; 754 secinfo->next = NULL; 755 756 /* Record the sections into the hash table. */ 757 align = 1; 758 for (secinfo = sinfo->chain; secinfo; secinfo = secinfo->next) 759 if (secinfo->sec->flags & SEC_EXCLUDE) 760 { 761 *secinfo->psecinfo = NULL; 762 if (remove_hook) 763 (*remove_hook) (abfd, secinfo->sec); 764 } 765 else 766 { 767 if (!record_section (sinfo, secinfo)) 768 return false; 769 if (align) 770 { 771 unsigned int opb = bfd_octets_per_byte (abfd, secinfo->sec); 772 773 align = (bfd_size_type) 1 << secinfo->sec->alignment_power; 774 if (((secinfo->sec->size / opb) & (align - 1)) != 0) 775 align = 0; 776 } 777 } 778 779 if (sinfo->htab->first == NULL) 780 continue; 781 782 if (sinfo->htab->strings) 783 { 784 secinfo = merge_strings (sinfo); 785 if (!secinfo) 786 return false; 787 } 788 else 789 { 790 struct sec_merge_hash_entry *e; 791 bfd_size_type size = 0; /* Octets. */ 792 793 /* Things are much simpler for non-strings. 794 Just assign them slots in the section. */ 795 secinfo = NULL; 796 for (e = sinfo->htab->first; e; e = e->next) 797 { 798 if (e->secinfo->first_str == NULL) 799 { 800 if (secinfo) 801 secinfo->sec->size = size; 802 e->secinfo->first_str = e; 803 size = 0; 804 } 805 size = (size + e->alignment - 1) & ~((bfd_vma) e->alignment - 1); 806 e->u.index = size; 807 size += e->len; 808 secinfo = e->secinfo; 809 } 810 secinfo->sec->size = size; 811 } 812 813 /* If the input sections were padded according to their alignments, 814 then pad the output too. */ 815 if (align) 816 secinfo->sec->size = (secinfo->sec->size + align - 1) & -align; 817 818 /* Finally remove all input sections which have not made it into 819 the hash table at all. */ 820 for (secinfo = sinfo->chain; secinfo; secinfo = secinfo->next) 821 if (secinfo->first_str == NULL) 822 secinfo->sec->flags |= SEC_EXCLUDE | SEC_KEEP; 823 } 824 825 return true; 826 } 827 828 /* Write out the merged section. */ 829 830 bool 831 _bfd_write_merged_section (bfd *output_bfd, asection *sec, void *psecinfo) 832 { 833 struct sec_merge_sec_info *secinfo; 834 file_ptr pos; 835 unsigned char *contents; 836 Elf_Internal_Shdr *hdr; 837 838 secinfo = (struct sec_merge_sec_info *) psecinfo; 839 840 if (!secinfo) 841 return false; 842 843 if (secinfo->first_str == NULL) 844 return true; 845 846 /* FIXME: octets_per_byte. */ 847 hdr = &elf_section_data (sec->output_section)->this_hdr; 848 if (hdr->sh_offset == (file_ptr) -1) 849 { 850 /* We must compress this section. Write output to the 851 buffer. */ 852 contents = hdr->contents; 853 if ((sec->output_section->flags & SEC_ELF_COMPRESS) == 0 854 || contents == NULL) 855 abort (); 856 } 857 else 858 { 859 contents = NULL; 860 pos = sec->output_section->filepos + sec->output_offset; 861 if (bfd_seek (output_bfd, pos, SEEK_SET) != 0) 862 return false; 863 } 864 865 if (! sec_merge_emit (output_bfd, secinfo->first_str, contents, 866 sec->output_offset)) 867 return false; 868 869 return true; 870 } 871 872 /* Adjust an address in the SEC_MERGE section. Given OFFSET within 873 *PSEC, this returns the new offset in the adjusted SEC_MERGE 874 section and writes the new section back into *PSEC. */ 875 876 bfd_vma 877 _bfd_merged_section_offset (bfd *output_bfd ATTRIBUTE_UNUSED, asection **psec, 878 void *psecinfo, bfd_vma offset) 879 { 880 struct sec_merge_sec_info *secinfo; 881 struct sec_merge_hash_entry *entry; 882 unsigned char *p; 883 asection *sec = *psec; 884 885 secinfo = (struct sec_merge_sec_info *) psecinfo; 886 887 if (!secinfo) 888 return offset; 889 890 if (offset >= sec->rawsize) 891 { 892 if (offset > sec->rawsize) 893 _bfd_error_handler 894 /* xgettext:c-format */ 895 (_("%pB: access beyond end of merged section (%" PRId64 ")"), 896 sec->owner, (int64_t) offset); 897 return secinfo->first_str ? sec->size : 0; 898 } 899 900 if (secinfo->htab->strings) 901 { 902 if (sec->entsize == 1) 903 { 904 p = secinfo->contents + offset - 1; 905 while (p >= secinfo->contents && *p) 906 --p; 907 ++p; 908 } 909 else 910 { 911 p = secinfo->contents + (offset / sec->entsize) * sec->entsize; 912 p -= sec->entsize; 913 while (p >= secinfo->contents) 914 { 915 unsigned int i; 916 917 for (i = 0; i < sec->entsize; ++i) 918 if (p[i] != '\0') 919 break; 920 if (i == sec->entsize) 921 break; 922 p -= sec->entsize; 923 } 924 p += sec->entsize; 925 } 926 } 927 else 928 { 929 p = secinfo->contents + (offset / sec->entsize) * sec->entsize; 930 } 931 entry = sec_merge_hash_lookup (secinfo->htab, (char *) p, 0, false); 932 if (!entry) 933 { 934 if (! secinfo->htab->strings) 935 abort (); 936 /* This should only happen if somebody points into the padding 937 after a NUL character but before next entity. */ 938 if (*p) 939 abort (); 940 if (! secinfo->htab->first) 941 abort (); 942 entry = secinfo->htab->first; 943 p = (secinfo->contents + (offset / sec->entsize + 1) * sec->entsize 944 - entry->len); 945 } 946 947 *psec = entry->secinfo->sec; 948 return entry->u.index + (secinfo->contents + offset - p); 949 } 950 951 /* Tidy up when done. */ 952 953 void 954 _bfd_merge_sections_free (void *xsinfo) 955 { 956 struct sec_merge_info *sinfo; 957 958 for (sinfo = (struct sec_merge_info *) xsinfo; sinfo; sinfo = sinfo->next) 959 { 960 bfd_hash_table_free (&sinfo->htab->table); 961 free (sinfo->htab); 962 } 963 } 964