1 /* linker.c -- BFD linker routines 2 Copyright (C) 1993-2018 Free Software Foundation, Inc. 3 Written by Steve Chamberlain and Ian Lance Taylor, Cygnus Support 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 #include "sysdep.h" 23 #include "bfd.h" 24 #include "libbfd.h" 25 #include "bfdlink.h" 26 #include "genlink.h" 27 28 /* 29 SECTION 30 Linker Functions 31 32 @cindex Linker 33 The linker uses three special entry points in the BFD target 34 vector. It is not necessary to write special routines for 35 these entry points when creating a new BFD back end, since 36 generic versions are provided. However, writing them can 37 speed up linking and make it use significantly less runtime 38 memory. 39 40 The first routine creates a hash table used by the other 41 routines. The second routine adds the symbols from an object 42 file to the hash table. The third routine takes all the 43 object files and links them together to create the output 44 file. These routines are designed so that the linker proper 45 does not need to know anything about the symbols in the object 46 files that it is linking. The linker merely arranges the 47 sections as directed by the linker script and lets BFD handle 48 the details of symbols and relocs. 49 50 The second routine and third routines are passed a pointer to 51 a <<struct bfd_link_info>> structure (defined in 52 <<bfdlink.h>>) which holds information relevant to the link, 53 including the linker hash table (which was created by the 54 first routine) and a set of callback functions to the linker 55 proper. 56 57 The generic linker routines are in <<linker.c>>, and use the 58 header file <<genlink.h>>. As of this writing, the only back 59 ends which have implemented versions of these routines are 60 a.out (in <<aoutx.h>>) and ECOFF (in <<ecoff.c>>). The a.out 61 routines are used as examples throughout this section. 62 63 @menu 64 @* Creating a Linker Hash Table:: 65 @* Adding Symbols to the Hash Table:: 66 @* Performing the Final Link:: 67 @end menu 68 69 INODE 70 Creating a Linker Hash Table, Adding Symbols to the Hash Table, Linker Functions, Linker Functions 71 SUBSECTION 72 Creating a linker hash table 73 74 @cindex _bfd_link_hash_table_create in target vector 75 @cindex target vector (_bfd_link_hash_table_create) 76 The linker routines must create a hash table, which must be 77 derived from <<struct bfd_link_hash_table>> described in 78 <<bfdlink.c>>. @xref{Hash Tables}, for information on how to 79 create a derived hash table. This entry point is called using 80 the target vector of the linker output file. 81 82 The <<_bfd_link_hash_table_create>> entry point must allocate 83 and initialize an instance of the desired hash table. If the 84 back end does not require any additional information to be 85 stored with the entries in the hash table, the entry point may 86 simply create a <<struct bfd_link_hash_table>>. Most likely, 87 however, some additional information will be needed. 88 89 For example, with each entry in the hash table the a.out 90 linker keeps the index the symbol has in the final output file 91 (this index number is used so that when doing a relocatable 92 link the symbol index used in the output file can be quickly 93 filled in when copying over a reloc). The a.out linker code 94 defines the required structures and functions for a hash table 95 derived from <<struct bfd_link_hash_table>>. The a.out linker 96 hash table is created by the function 97 <<NAME(aout,link_hash_table_create)>>; it simply allocates 98 space for the hash table, initializes it, and returns a 99 pointer to it. 100 101 When writing the linker routines for a new back end, you will 102 generally not know exactly which fields will be required until 103 you have finished. You should simply create a new hash table 104 which defines no additional fields, and then simply add fields 105 as they become necessary. 106 107 INODE 108 Adding Symbols to the Hash Table, Performing the Final Link, Creating a Linker Hash Table, Linker Functions 109 SUBSECTION 110 Adding symbols to the hash table 111 112 @cindex _bfd_link_add_symbols in target vector 113 @cindex target vector (_bfd_link_add_symbols) 114 The linker proper will call the <<_bfd_link_add_symbols>> 115 entry point for each object file or archive which is to be 116 linked (typically these are the files named on the command 117 line, but some may also come from the linker script). The 118 entry point is responsible for examining the file. For an 119 object file, BFD must add any relevant symbol information to 120 the hash table. For an archive, BFD must determine which 121 elements of the archive should be used and adding them to the 122 link. 123 124 The a.out version of this entry point is 125 <<NAME(aout,link_add_symbols)>>. 126 127 @menu 128 @* Differing file formats:: 129 @* Adding symbols from an object file:: 130 @* Adding symbols from an archive:: 131 @end menu 132 133 INODE 134 Differing file formats, Adding symbols from an object file, Adding Symbols to the Hash Table, Adding Symbols to the Hash Table 135 SUBSUBSECTION 136 Differing file formats 137 138 Normally all the files involved in a link will be of the same 139 format, but it is also possible to link together different 140 format object files, and the back end must support that. The 141 <<_bfd_link_add_symbols>> entry point is called via the target 142 vector of the file to be added. This has an important 143 consequence: the function may not assume that the hash table 144 is the type created by the corresponding 145 <<_bfd_link_hash_table_create>> vector. All the 146 <<_bfd_link_add_symbols>> function can assume about the hash 147 table is that it is derived from <<struct 148 bfd_link_hash_table>>. 149 150 Sometimes the <<_bfd_link_add_symbols>> function must store 151 some information in the hash table entry to be used by the 152 <<_bfd_final_link>> function. In such a case the output bfd 153 xvec must be checked to make sure that the hash table was 154 created by an object file of the same format. 155 156 The <<_bfd_final_link>> routine must be prepared to handle a 157 hash entry without any extra information added by the 158 <<_bfd_link_add_symbols>> function. A hash entry without 159 extra information will also occur when the linker script 160 directs the linker to create a symbol. Note that, regardless 161 of how a hash table entry is added, all the fields will be 162 initialized to some sort of null value by the hash table entry 163 initialization function. 164 165 See <<ecoff_link_add_externals>> for an example of how to 166 check the output bfd before saving information (in this 167 case, the ECOFF external symbol debugging information) in a 168 hash table entry. 169 170 INODE 171 Adding symbols from an object file, Adding symbols from an archive, Differing file formats, Adding Symbols to the Hash Table 172 SUBSUBSECTION 173 Adding symbols from an object file 174 175 When the <<_bfd_link_add_symbols>> routine is passed an object 176 file, it must add all externally visible symbols in that 177 object file to the hash table. The actual work of adding the 178 symbol to the hash table is normally handled by the function 179 <<_bfd_generic_link_add_one_symbol>>. The 180 <<_bfd_link_add_symbols>> routine is responsible for reading 181 all the symbols from the object file and passing the correct 182 information to <<_bfd_generic_link_add_one_symbol>>. 183 184 The <<_bfd_link_add_symbols>> routine should not use 185 <<bfd_canonicalize_symtab>> to read the symbols. The point of 186 providing this routine is to avoid the overhead of converting 187 the symbols into generic <<asymbol>> structures. 188 189 @findex _bfd_generic_link_add_one_symbol 190 <<_bfd_generic_link_add_one_symbol>> handles the details of 191 combining common symbols, warning about multiple definitions, 192 and so forth. It takes arguments which describe the symbol to 193 add, notably symbol flags, a section, and an offset. The 194 symbol flags include such things as <<BSF_WEAK>> or 195 <<BSF_INDIRECT>>. The section is a section in the object 196 file, or something like <<bfd_und_section_ptr>> for an undefined 197 symbol or <<bfd_com_section_ptr>> for a common symbol. 198 199 If the <<_bfd_final_link>> routine is also going to need to 200 read the symbol information, the <<_bfd_link_add_symbols>> 201 routine should save it somewhere attached to the object file 202 BFD. However, the information should only be saved if the 203 <<keep_memory>> field of the <<info>> argument is TRUE, so 204 that the <<-no-keep-memory>> linker switch is effective. 205 206 The a.out function which adds symbols from an object file is 207 <<aout_link_add_object_symbols>>, and most of the interesting 208 work is in <<aout_link_add_symbols>>. The latter saves 209 pointers to the hash tables entries created by 210 <<_bfd_generic_link_add_one_symbol>> indexed by symbol number, 211 so that the <<_bfd_final_link>> routine does not have to call 212 the hash table lookup routine to locate the entry. 213 214 INODE 215 Adding symbols from an archive, , Adding symbols from an object file, Adding Symbols to the Hash Table 216 SUBSUBSECTION 217 Adding symbols from an archive 218 219 When the <<_bfd_link_add_symbols>> routine is passed an 220 archive, it must look through the symbols defined by the 221 archive and decide which elements of the archive should be 222 included in the link. For each such element it must call the 223 <<add_archive_element>> linker callback, and it must add the 224 symbols from the object file to the linker hash table. (The 225 callback may in fact indicate that a replacement BFD should be 226 used, in which case the symbols from that BFD should be added 227 to the linker hash table instead.) 228 229 @findex _bfd_generic_link_add_archive_symbols 230 In most cases the work of looking through the symbols in the 231 archive should be done by the 232 <<_bfd_generic_link_add_archive_symbols>> function. 233 <<_bfd_generic_link_add_archive_symbols>> is passed a function 234 to call to make the final decision about adding an archive 235 element to the link and to do the actual work of adding the 236 symbols to the linker hash table. If the element is to 237 be included, the <<add_archive_element>> linker callback 238 routine must be called with the element as an argument, and 239 the element's symbols must be added to the linker hash table 240 just as though the element had itself been passed to the 241 <<_bfd_link_add_symbols>> function. 242 243 When the a.out <<_bfd_link_add_symbols>> function receives an 244 archive, it calls <<_bfd_generic_link_add_archive_symbols>> 245 passing <<aout_link_check_archive_element>> as the function 246 argument. <<aout_link_check_archive_element>> calls 247 <<aout_link_check_ar_symbols>>. If the latter decides to add 248 the element (an element is only added if it provides a real, 249 non-common, definition for a previously undefined or common 250 symbol) it calls the <<add_archive_element>> callback and then 251 <<aout_link_check_archive_element>> calls 252 <<aout_link_add_symbols>> to actually add the symbols to the 253 linker hash table - possibly those of a substitute BFD, if the 254 <<add_archive_element>> callback avails itself of that option. 255 256 The ECOFF back end is unusual in that it does not normally 257 call <<_bfd_generic_link_add_archive_symbols>>, because ECOFF 258 archives already contain a hash table of symbols. The ECOFF 259 back end searches the archive itself to avoid the overhead of 260 creating a new hash table. 261 262 INODE 263 Performing the Final Link, , Adding Symbols to the Hash Table, Linker Functions 264 SUBSECTION 265 Performing the final link 266 267 @cindex _bfd_link_final_link in target vector 268 @cindex target vector (_bfd_final_link) 269 When all the input files have been processed, the linker calls 270 the <<_bfd_final_link>> entry point of the output BFD. This 271 routine is responsible for producing the final output file, 272 which has several aspects. It must relocate the contents of 273 the input sections and copy the data into the output sections. 274 It must build an output symbol table including any local 275 symbols from the input files and the global symbols from the 276 hash table. When producing relocatable output, it must 277 modify the input relocs and write them into the output file. 278 There may also be object format dependent work to be done. 279 280 The linker will also call the <<write_object_contents>> entry 281 point when the BFD is closed. The two entry points must work 282 together in order to produce the correct output file. 283 284 The details of how this works are inevitably dependent upon 285 the specific object file format. The a.out 286 <<_bfd_final_link>> routine is <<NAME(aout,final_link)>>. 287 288 @menu 289 @* Information provided by the linker:: 290 @* Relocating the section contents:: 291 @* Writing the symbol table:: 292 @end menu 293 294 INODE 295 Information provided by the linker, Relocating the section contents, Performing the Final Link, Performing the Final Link 296 SUBSUBSECTION 297 Information provided by the linker 298 299 Before the linker calls the <<_bfd_final_link>> entry point, 300 it sets up some data structures for the function to use. 301 302 The <<input_bfds>> field of the <<bfd_link_info>> structure 303 will point to a list of all the input files included in the 304 link. These files are linked through the <<link.next>> field 305 of the <<bfd>> structure. 306 307 Each section in the output file will have a list of 308 <<link_order>> structures attached to the <<map_head.link_order>> 309 field (the <<link_order>> structure is defined in 310 <<bfdlink.h>>). These structures describe how to create the 311 contents of the output section in terms of the contents of 312 various input sections, fill constants, and, eventually, other 313 types of information. They also describe relocs that must be 314 created by the BFD backend, but do not correspond to any input 315 file; this is used to support -Ur, which builds constructors 316 while generating a relocatable object file. 317 318 INODE 319 Relocating the section contents, Writing the symbol table, Information provided by the linker, Performing the Final Link 320 SUBSUBSECTION 321 Relocating the section contents 322 323 The <<_bfd_final_link>> function should look through the 324 <<link_order>> structures attached to each section of the 325 output file. Each <<link_order>> structure should either be 326 handled specially, or it should be passed to the function 327 <<_bfd_default_link_order>> which will do the right thing 328 (<<_bfd_default_link_order>> is defined in <<linker.c>>). 329 330 For efficiency, a <<link_order>> of type 331 <<bfd_indirect_link_order>> whose associated section belongs 332 to a BFD of the same format as the output BFD must be handled 333 specially. This type of <<link_order>> describes part of an 334 output section in terms of a section belonging to one of the 335 input files. The <<_bfd_final_link>> function should read the 336 contents of the section and any associated relocs, apply the 337 relocs to the section contents, and write out the modified 338 section contents. If performing a relocatable link, the 339 relocs themselves must also be modified and written out. 340 341 @findex _bfd_relocate_contents 342 @findex _bfd_final_link_relocate 343 The functions <<_bfd_relocate_contents>> and 344 <<_bfd_final_link_relocate>> provide some general support for 345 performing the actual relocations, notably overflow checking. 346 Their arguments include information about the symbol the 347 relocation is against and a <<reloc_howto_type>> argument 348 which describes the relocation to perform. These functions 349 are defined in <<reloc.c>>. 350 351 The a.out function which handles reading, relocating, and 352 writing section contents is <<aout_link_input_section>>. The 353 actual relocation is done in <<aout_link_input_section_std>> 354 and <<aout_link_input_section_ext>>. 355 356 INODE 357 Writing the symbol table, , Relocating the section contents, Performing the Final Link 358 SUBSUBSECTION 359 Writing the symbol table 360 361 The <<_bfd_final_link>> function must gather all the symbols 362 in the input files and write them out. It must also write out 363 all the symbols in the global hash table. This must be 364 controlled by the <<strip>> and <<discard>> fields of the 365 <<bfd_link_info>> structure. 366 367 The local symbols of the input files will not have been 368 entered into the linker hash table. The <<_bfd_final_link>> 369 routine must consider each input file and include the symbols 370 in the output file. It may be convenient to do this when 371 looking through the <<link_order>> structures, or it may be 372 done by stepping through the <<input_bfds>> list. 373 374 The <<_bfd_final_link>> routine must also traverse the global 375 hash table to gather all the externally visible symbols. It 376 is possible that most of the externally visible symbols may be 377 written out when considering the symbols of each input file, 378 but it is still necessary to traverse the hash table since the 379 linker script may have defined some symbols that are not in 380 any of the input files. 381 382 The <<strip>> field of the <<bfd_link_info>> structure 383 controls which symbols are written out. The possible values 384 are listed in <<bfdlink.h>>. If the value is <<strip_some>>, 385 then the <<keep_hash>> field of the <<bfd_link_info>> 386 structure is a hash table of symbols to keep; each symbol 387 should be looked up in this hash table, and only symbols which 388 are present should be included in the output file. 389 390 If the <<strip>> field of the <<bfd_link_info>> structure 391 permits local symbols to be written out, the <<discard>> field 392 is used to further controls which local symbols are included 393 in the output file. If the value is <<discard_l>>, then all 394 local symbols which begin with a certain prefix are discarded; 395 this is controlled by the <<bfd_is_local_label_name>> entry point. 396 397 The a.out backend handles symbols by calling 398 <<aout_link_write_symbols>> on each input BFD and then 399 traversing the global hash table with the function 400 <<aout_link_write_other_symbol>>. It builds a string table 401 while writing out the symbols, which is written to the output 402 file at the end of <<NAME(aout,final_link)>>. 403 */ 404 405 static bfd_boolean generic_link_add_object_symbols 406 (bfd *, struct bfd_link_info *); 407 static bfd_boolean generic_link_check_archive_element 408 (bfd *, struct bfd_link_info *, struct bfd_link_hash_entry *, const char *, 409 bfd_boolean *); 410 static bfd_boolean generic_link_add_symbol_list 411 (bfd *, struct bfd_link_info *, bfd_size_type count, asymbol **); 412 static bfd_boolean generic_add_output_symbol 413 (bfd *, size_t *psymalloc, asymbol *); 414 static bfd_boolean default_data_link_order 415 (bfd *, struct bfd_link_info *, asection *, struct bfd_link_order *); 416 static bfd_boolean default_indirect_link_order 417 (bfd *, struct bfd_link_info *, asection *, struct bfd_link_order *, 418 bfd_boolean); 419 420 /* The link hash table structure is defined in bfdlink.h. It provides 421 a base hash table which the backend specific hash tables are built 422 upon. */ 423 424 /* Routine to create an entry in the link hash table. */ 425 426 struct bfd_hash_entry * 427 _bfd_link_hash_newfunc (struct bfd_hash_entry *entry, 428 struct bfd_hash_table *table, 429 const char *string) 430 { 431 /* Allocate the structure if it has not already been allocated by a 432 subclass. */ 433 if (entry == NULL) 434 { 435 entry = (struct bfd_hash_entry *) 436 bfd_hash_allocate (table, sizeof (struct bfd_link_hash_entry)); 437 if (entry == NULL) 438 return entry; 439 } 440 441 /* Call the allocation method of the superclass. */ 442 entry = bfd_hash_newfunc (entry, table, string); 443 if (entry) 444 { 445 struct bfd_link_hash_entry *h = (struct bfd_link_hash_entry *) entry; 446 447 /* Initialize the local fields. */ 448 memset ((char *) &h->root + sizeof (h->root), 0, 449 sizeof (*h) - sizeof (h->root)); 450 } 451 452 return entry; 453 } 454 455 /* Initialize a link hash table. The BFD argument is the one 456 responsible for creating this table. */ 457 458 bfd_boolean 459 _bfd_link_hash_table_init 460 (struct bfd_link_hash_table *table, 461 bfd *abfd ATTRIBUTE_UNUSED, 462 struct bfd_hash_entry *(*newfunc) (struct bfd_hash_entry *, 463 struct bfd_hash_table *, 464 const char *), 465 unsigned int entsize) 466 { 467 bfd_boolean ret; 468 469 BFD_ASSERT (!abfd->is_linker_output && !abfd->link.hash); 470 table->undefs = NULL; 471 table->undefs_tail = NULL; 472 table->type = bfd_link_generic_hash_table; 473 474 ret = bfd_hash_table_init (&table->table, newfunc, entsize); 475 if (ret) 476 { 477 /* Arrange for destruction of this hash table on closing ABFD. */ 478 table->hash_table_free = _bfd_generic_link_hash_table_free; 479 abfd->link.hash = table; 480 abfd->is_linker_output = TRUE; 481 } 482 return ret; 483 } 484 485 /* Look up a symbol in a link hash table. If follow is TRUE, we 486 follow bfd_link_hash_indirect and bfd_link_hash_warning links to 487 the real symbol. */ 488 489 struct bfd_link_hash_entry * 490 bfd_link_hash_lookup (struct bfd_link_hash_table *table, 491 const char *string, 492 bfd_boolean create, 493 bfd_boolean copy, 494 bfd_boolean follow) 495 { 496 struct bfd_link_hash_entry *ret; 497 498 ret = ((struct bfd_link_hash_entry *) 499 bfd_hash_lookup (&table->table, string, create, copy)); 500 501 if (follow && ret != NULL) 502 { 503 while (ret->type == bfd_link_hash_indirect 504 || ret->type == bfd_link_hash_warning) 505 ret = ret->u.i.link; 506 } 507 508 return ret; 509 } 510 511 /* Look up a symbol in the main linker hash table if the symbol might 512 be wrapped. This should only be used for references to an 513 undefined symbol, not for definitions of a symbol. */ 514 515 struct bfd_link_hash_entry * 516 bfd_wrapped_link_hash_lookup (bfd *abfd, 517 struct bfd_link_info *info, 518 const char *string, 519 bfd_boolean create, 520 bfd_boolean copy, 521 bfd_boolean follow) 522 { 523 bfd_size_type amt; 524 525 if (info->wrap_hash != NULL) 526 { 527 const char *l; 528 char prefix = '\0'; 529 530 l = string; 531 if (*l == bfd_get_symbol_leading_char (abfd) || *l == info->wrap_char) 532 { 533 prefix = *l; 534 ++l; 535 } 536 537 #undef WRAP 538 #define WRAP "__wrap_" 539 540 if (bfd_hash_lookup (info->wrap_hash, l, FALSE, FALSE) != NULL) 541 { 542 char *n; 543 struct bfd_link_hash_entry *h; 544 545 /* This symbol is being wrapped. We want to replace all 546 references to SYM with references to __wrap_SYM. */ 547 548 amt = strlen (l) + sizeof WRAP + 1; 549 n = (char *) bfd_malloc (amt); 550 if (n == NULL) 551 return NULL; 552 553 n[0] = prefix; 554 n[1] = '\0'; 555 strcat (n, WRAP); 556 strcat (n, l); 557 h = bfd_link_hash_lookup (info->hash, n, create, TRUE, follow); 558 free (n); 559 return h; 560 } 561 562 #undef REAL 563 #define REAL "__real_" 564 565 if (*l == '_' 566 && CONST_STRNEQ (l, REAL) 567 && bfd_hash_lookup (info->wrap_hash, l + sizeof REAL - 1, 568 FALSE, FALSE) != NULL) 569 { 570 char *n; 571 struct bfd_link_hash_entry *h; 572 573 /* This is a reference to __real_SYM, where SYM is being 574 wrapped. We want to replace all references to __real_SYM 575 with references to SYM. */ 576 577 amt = strlen (l + sizeof REAL - 1) + 2; 578 n = (char *) bfd_malloc (amt); 579 if (n == NULL) 580 return NULL; 581 582 n[0] = prefix; 583 n[1] = '\0'; 584 strcat (n, l + sizeof REAL - 1); 585 h = bfd_link_hash_lookup (info->hash, n, create, TRUE, follow); 586 free (n); 587 return h; 588 } 589 590 #undef REAL 591 } 592 593 return bfd_link_hash_lookup (info->hash, string, create, copy, follow); 594 } 595 596 /* If H is a wrapped symbol, ie. the symbol name starts with "__wrap_" 597 and the remainder is found in wrap_hash, return the real symbol. */ 598 599 struct bfd_link_hash_entry * 600 unwrap_hash_lookup (struct bfd_link_info *info, 601 bfd *input_bfd, 602 struct bfd_link_hash_entry *h) 603 { 604 const char *l = h->root.string; 605 606 if (*l == bfd_get_symbol_leading_char (input_bfd) 607 || *l == info->wrap_char) 608 ++l; 609 610 if (CONST_STRNEQ (l, WRAP)) 611 { 612 l += sizeof WRAP - 1; 613 614 if (bfd_hash_lookup (info->wrap_hash, l, FALSE, FALSE) != NULL) 615 { 616 char save = 0; 617 if (l - (sizeof WRAP - 1) != h->root.string) 618 { 619 --l; 620 save = *l; 621 *(char *) l = *h->root.string; 622 } 623 h = bfd_link_hash_lookup (info->hash, l, FALSE, FALSE, FALSE); 624 if (save) 625 *(char *) l = save; 626 } 627 } 628 return h; 629 } 630 #undef WRAP 631 632 /* Traverse a generic link hash table. Differs from bfd_hash_traverse 633 in the treatment of warning symbols. When warning symbols are 634 created they replace the real symbol, so you don't get to see the 635 real symbol in a bfd_hash_traverse. This traversal calls func with 636 the real symbol. */ 637 638 void 639 bfd_link_hash_traverse 640 (struct bfd_link_hash_table *htab, 641 bfd_boolean (*func) (struct bfd_link_hash_entry *, void *), 642 void *info) 643 { 644 unsigned int i; 645 646 htab->table.frozen = 1; 647 for (i = 0; i < htab->table.size; i++) 648 { 649 struct bfd_link_hash_entry *p; 650 651 p = (struct bfd_link_hash_entry *) htab->table.table[i]; 652 for (; p != NULL; p = (struct bfd_link_hash_entry *) p->root.next) 653 if (!(*func) (p->type == bfd_link_hash_warning ? p->u.i.link : p, info)) 654 goto out; 655 } 656 out: 657 htab->table.frozen = 0; 658 } 659 660 /* Add a symbol to the linker hash table undefs list. */ 661 662 void 663 bfd_link_add_undef (struct bfd_link_hash_table *table, 664 struct bfd_link_hash_entry *h) 665 { 666 BFD_ASSERT (h->u.undef.next == NULL); 667 if (table->undefs_tail != NULL) 668 table->undefs_tail->u.undef.next = h; 669 if (table->undefs == NULL) 670 table->undefs = h; 671 table->undefs_tail = h; 672 } 673 674 /* The undefs list was designed so that in normal use we don't need to 675 remove entries. However, if symbols on the list are changed from 676 bfd_link_hash_undefined to either bfd_link_hash_undefweak or 677 bfd_link_hash_new for some reason, then they must be removed from the 678 list. Failure to do so might result in the linker attempting to add 679 the symbol to the list again at a later stage. */ 680 681 void 682 bfd_link_repair_undef_list (struct bfd_link_hash_table *table) 683 { 684 struct bfd_link_hash_entry **pun; 685 686 pun = &table->undefs; 687 while (*pun != NULL) 688 { 689 struct bfd_link_hash_entry *h = *pun; 690 691 if (h->type == bfd_link_hash_new 692 || h->type == bfd_link_hash_undefweak) 693 { 694 *pun = h->u.undef.next; 695 h->u.undef.next = NULL; 696 if (h == table->undefs_tail) 697 { 698 if (pun == &table->undefs) 699 table->undefs_tail = NULL; 700 else 701 /* pun points at an u.undef.next field. Go back to 702 the start of the link_hash_entry. */ 703 table->undefs_tail = (struct bfd_link_hash_entry *) 704 ((char *) pun - ((char *) &h->u.undef.next - (char *) h)); 705 break; 706 } 707 } 708 else 709 pun = &h->u.undef.next; 710 } 711 } 712 713 /* Routine to create an entry in a generic link hash table. */ 714 715 struct bfd_hash_entry * 716 _bfd_generic_link_hash_newfunc (struct bfd_hash_entry *entry, 717 struct bfd_hash_table *table, 718 const char *string) 719 { 720 /* Allocate the structure if it has not already been allocated by a 721 subclass. */ 722 if (entry == NULL) 723 { 724 entry = (struct bfd_hash_entry *) 725 bfd_hash_allocate (table, sizeof (struct generic_link_hash_entry)); 726 if (entry == NULL) 727 return entry; 728 } 729 730 /* Call the allocation method of the superclass. */ 731 entry = _bfd_link_hash_newfunc (entry, table, string); 732 if (entry) 733 { 734 struct generic_link_hash_entry *ret; 735 736 /* Set local fields. */ 737 ret = (struct generic_link_hash_entry *) entry; 738 ret->written = FALSE; 739 ret->sym = NULL; 740 } 741 742 return entry; 743 } 744 745 /* Create a generic link hash table. */ 746 747 struct bfd_link_hash_table * 748 _bfd_generic_link_hash_table_create (bfd *abfd) 749 { 750 struct generic_link_hash_table *ret; 751 bfd_size_type amt = sizeof (struct generic_link_hash_table); 752 753 ret = (struct generic_link_hash_table *) bfd_malloc (amt); 754 if (ret == NULL) 755 return NULL; 756 if (! _bfd_link_hash_table_init (&ret->root, abfd, 757 _bfd_generic_link_hash_newfunc, 758 sizeof (struct generic_link_hash_entry))) 759 { 760 free (ret); 761 return NULL; 762 } 763 return &ret->root; 764 } 765 766 void 767 _bfd_generic_link_hash_table_free (bfd *obfd) 768 { 769 struct generic_link_hash_table *ret; 770 771 BFD_ASSERT (obfd->is_linker_output && obfd->link.hash); 772 ret = (struct generic_link_hash_table *) obfd->link.hash; 773 bfd_hash_table_free (&ret->root.table); 774 free (ret); 775 obfd->link.hash = NULL; 776 obfd->is_linker_output = FALSE; 777 } 778 779 /* Grab the symbols for an object file when doing a generic link. We 780 store the symbols in the outsymbols field. We need to keep them 781 around for the entire link to ensure that we only read them once. 782 If we read them multiple times, we might wind up with relocs and 783 the hash table pointing to different instances of the symbol 784 structure. */ 785 786 bfd_boolean 787 bfd_generic_link_read_symbols (bfd *abfd) 788 { 789 if (bfd_get_outsymbols (abfd) == NULL) 790 { 791 long symsize; 792 long symcount; 793 794 symsize = bfd_get_symtab_upper_bound (abfd); 795 if (symsize < 0) 796 return FALSE; 797 bfd_get_outsymbols (abfd) = (struct bfd_symbol **) bfd_alloc (abfd, 798 symsize); 799 if (bfd_get_outsymbols (abfd) == NULL && symsize != 0) 800 return FALSE; 801 symcount = bfd_canonicalize_symtab (abfd, bfd_get_outsymbols (abfd)); 802 if (symcount < 0) 803 return FALSE; 804 bfd_get_symcount (abfd) = symcount; 805 } 806 807 return TRUE; 808 } 809 810 /* Indicate that we are only retrieving symbol values from this 811 section. We want the symbols to act as though the values in the 812 file are absolute. */ 813 814 void 815 _bfd_generic_link_just_syms (asection *sec, 816 struct bfd_link_info *info ATTRIBUTE_UNUSED) 817 { 818 sec->sec_info_type = SEC_INFO_TYPE_JUST_SYMS; 819 sec->output_section = bfd_abs_section_ptr; 820 sec->output_offset = sec->vma; 821 } 822 823 /* Copy the symbol type and other attributes for a linker script 824 assignment from HSRC to HDEST. 825 The default implementation does nothing. */ 826 void 827 _bfd_generic_copy_link_hash_symbol_type (bfd *abfd ATTRIBUTE_UNUSED, 828 struct bfd_link_hash_entry *hdest ATTRIBUTE_UNUSED, 829 struct bfd_link_hash_entry *hsrc ATTRIBUTE_UNUSED) 830 { 831 } 832 833 /* Generic function to add symbols from an object file to the 834 global hash table. */ 835 836 bfd_boolean 837 _bfd_generic_link_add_symbols (bfd *abfd, struct bfd_link_info *info) 838 { 839 bfd_boolean ret; 840 841 switch (bfd_get_format (abfd)) 842 { 843 case bfd_object: 844 ret = generic_link_add_object_symbols (abfd, info); 845 break; 846 case bfd_archive: 847 ret = (_bfd_generic_link_add_archive_symbols 848 (abfd, info, generic_link_check_archive_element)); 849 break; 850 default: 851 bfd_set_error (bfd_error_wrong_format); 852 ret = FALSE; 853 } 854 855 return ret; 856 } 857 858 /* Add symbols from an object file to the global hash table. */ 859 860 static bfd_boolean 861 generic_link_add_object_symbols (bfd *abfd, 862 struct bfd_link_info *info) 863 { 864 bfd_size_type symcount; 865 struct bfd_symbol **outsyms; 866 867 if (!bfd_generic_link_read_symbols (abfd)) 868 return FALSE; 869 symcount = _bfd_generic_link_get_symcount (abfd); 870 outsyms = _bfd_generic_link_get_symbols (abfd); 871 return generic_link_add_symbol_list (abfd, info, symcount, outsyms); 872 } 873 874 /* Generic function to add symbols from an archive file to the global 875 hash file. This function presumes that the archive symbol table 876 has already been read in (this is normally done by the 877 bfd_check_format entry point). It looks through the archive symbol 878 table for symbols that are undefined or common in the linker global 879 symbol hash table. When one is found, the CHECKFN argument is used 880 to see if an object file should be included. This allows targets 881 to customize common symbol behaviour. CHECKFN should set *PNEEDED 882 to TRUE if the object file should be included, and must also call 883 the bfd_link_info add_archive_element callback function and handle 884 adding the symbols to the global hash table. CHECKFN must notice 885 if the callback indicates a substitute BFD, and arrange to add 886 those symbols instead if it does so. CHECKFN should only return 887 FALSE if some sort of error occurs. */ 888 889 bfd_boolean 890 _bfd_generic_link_add_archive_symbols 891 (bfd *abfd, 892 struct bfd_link_info *info, 893 bfd_boolean (*checkfn) (bfd *, struct bfd_link_info *, 894 struct bfd_link_hash_entry *, const char *, 895 bfd_boolean *)) 896 { 897 bfd_boolean loop; 898 bfd_size_type amt; 899 unsigned char *included; 900 901 if (! bfd_has_map (abfd)) 902 { 903 /* An empty archive is a special case. */ 904 if (bfd_openr_next_archived_file (abfd, NULL) == NULL) 905 return TRUE; 906 bfd_set_error (bfd_error_no_armap); 907 return FALSE; 908 } 909 910 amt = bfd_ardata (abfd)->symdef_count; 911 if (amt == 0) 912 return TRUE; 913 amt *= sizeof (*included); 914 included = (unsigned char *) bfd_zmalloc (amt); 915 if (included == NULL) 916 return FALSE; 917 918 do 919 { 920 carsym *arsyms; 921 carsym *arsym_end; 922 carsym *arsym; 923 unsigned int indx; 924 file_ptr last_ar_offset = -1; 925 bfd_boolean needed = FALSE; 926 bfd *element = NULL; 927 928 loop = FALSE; 929 arsyms = bfd_ardata (abfd)->symdefs; 930 arsym_end = arsyms + bfd_ardata (abfd)->symdef_count; 931 for (arsym = arsyms, indx = 0; arsym < arsym_end; arsym++, indx++) 932 { 933 struct bfd_link_hash_entry *h; 934 struct bfd_link_hash_entry *undefs_tail; 935 936 if (included[indx]) 937 continue; 938 if (needed && arsym->file_offset == last_ar_offset) 939 { 940 included[indx] = 1; 941 continue; 942 } 943 944 h = bfd_link_hash_lookup (info->hash, arsym->name, 945 FALSE, FALSE, TRUE); 946 947 if (h == NULL 948 && info->pei386_auto_import 949 && CONST_STRNEQ (arsym->name, "__imp_")) 950 h = bfd_link_hash_lookup (info->hash, arsym->name + 6, 951 FALSE, FALSE, TRUE); 952 if (h == NULL) 953 continue; 954 955 if (h->type != bfd_link_hash_undefined 956 && h->type != bfd_link_hash_common) 957 { 958 if (h->type != bfd_link_hash_undefweak) 959 /* Symbol must be defined. Don't check it again. */ 960 included[indx] = 1; 961 continue; 962 } 963 964 if (last_ar_offset != arsym->file_offset) 965 { 966 last_ar_offset = arsym->file_offset; 967 element = _bfd_get_elt_at_filepos (abfd, last_ar_offset); 968 if (element == NULL 969 || !bfd_check_format (element, bfd_object)) 970 goto error_return; 971 } 972 973 undefs_tail = info->hash->undefs_tail; 974 975 /* CHECKFN will see if this element should be included, and 976 go ahead and include it if appropriate. */ 977 if (! (*checkfn) (element, info, h, arsym->name, &needed)) 978 goto error_return; 979 980 if (needed) 981 { 982 unsigned int mark; 983 984 /* Look backward to mark all symbols from this object file 985 which we have already seen in this pass. */ 986 mark = indx; 987 do 988 { 989 included[mark] = 1; 990 if (mark == 0) 991 break; 992 --mark; 993 } 994 while (arsyms[mark].file_offset == last_ar_offset); 995 996 if (undefs_tail != info->hash->undefs_tail) 997 loop = TRUE; 998 } 999 } 1000 } while (loop); 1001 1002 free (included); 1003 return TRUE; 1004 1005 error_return: 1006 free (included); 1007 return FALSE; 1008 } 1009 1010 /* See if we should include an archive element. */ 1011 1012 static bfd_boolean 1013 generic_link_check_archive_element (bfd *abfd, 1014 struct bfd_link_info *info, 1015 struct bfd_link_hash_entry *h, 1016 const char *name ATTRIBUTE_UNUSED, 1017 bfd_boolean *pneeded) 1018 { 1019 asymbol **pp, **ppend; 1020 1021 *pneeded = FALSE; 1022 1023 if (!bfd_generic_link_read_symbols (abfd)) 1024 return FALSE; 1025 1026 pp = _bfd_generic_link_get_symbols (abfd); 1027 ppend = pp + _bfd_generic_link_get_symcount (abfd); 1028 for (; pp < ppend; pp++) 1029 { 1030 asymbol *p; 1031 1032 p = *pp; 1033 1034 /* We are only interested in globally visible symbols. */ 1035 if (! bfd_is_com_section (p->section) 1036 && (p->flags & (BSF_GLOBAL | BSF_INDIRECT | BSF_WEAK)) == 0) 1037 continue; 1038 1039 /* We are only interested if we know something about this 1040 symbol, and it is undefined or common. An undefined weak 1041 symbol (type bfd_link_hash_undefweak) is not considered to be 1042 a reference when pulling files out of an archive. See the 1043 SVR4 ABI, p. 4-27. */ 1044 h = bfd_link_hash_lookup (info->hash, bfd_asymbol_name (p), FALSE, 1045 FALSE, TRUE); 1046 if (h == NULL 1047 || (h->type != bfd_link_hash_undefined 1048 && h->type != bfd_link_hash_common)) 1049 continue; 1050 1051 /* P is a symbol we are looking for. */ 1052 1053 if (! bfd_is_com_section (p->section) 1054 || (h->type == bfd_link_hash_undefined 1055 && h->u.undef.abfd == NULL)) 1056 { 1057 /* P is not a common symbol, or an undefined reference was 1058 created from outside BFD such as from a linker -u option. 1059 This object file defines the symbol, so pull it in. */ 1060 *pneeded = TRUE; 1061 if (!(*info->callbacks 1062 ->add_archive_element) (info, abfd, bfd_asymbol_name (p), 1063 &abfd)) 1064 return FALSE; 1065 /* Potentially, the add_archive_element hook may have set a 1066 substitute BFD for us. */ 1067 return bfd_link_add_symbols (abfd, info); 1068 } 1069 1070 /* P is a common symbol. */ 1071 1072 if (h->type == bfd_link_hash_undefined) 1073 { 1074 bfd *symbfd; 1075 bfd_vma size; 1076 unsigned int power; 1077 1078 /* Turn the symbol into a common symbol but do not link in 1079 the object file. This is how a.out works. Object 1080 formats that require different semantics must implement 1081 this function differently. This symbol is already on the 1082 undefs list. We add the section to a common section 1083 attached to symbfd to ensure that it is in a BFD which 1084 will be linked in. */ 1085 symbfd = h->u.undef.abfd; 1086 h->type = bfd_link_hash_common; 1087 h->u.c.p = (struct bfd_link_hash_common_entry *) 1088 bfd_hash_allocate (&info->hash->table, 1089 sizeof (struct bfd_link_hash_common_entry)); 1090 if (h->u.c.p == NULL) 1091 return FALSE; 1092 1093 size = bfd_asymbol_value (p); 1094 h->u.c.size = size; 1095 1096 power = bfd_log2 (size); 1097 if (power > 4) 1098 power = 4; 1099 h->u.c.p->alignment_power = power; 1100 1101 if (p->section == bfd_com_section_ptr) 1102 h->u.c.p->section = bfd_make_section_old_way (symbfd, "COMMON"); 1103 else 1104 h->u.c.p->section = bfd_make_section_old_way (symbfd, 1105 p->section->name); 1106 h->u.c.p->section->flags |= SEC_ALLOC; 1107 } 1108 else 1109 { 1110 /* Adjust the size of the common symbol if necessary. This 1111 is how a.out works. Object formats that require 1112 different semantics must implement this function 1113 differently. */ 1114 if (bfd_asymbol_value (p) > h->u.c.size) 1115 h->u.c.size = bfd_asymbol_value (p); 1116 } 1117 } 1118 1119 /* This archive element is not needed. */ 1120 return TRUE; 1121 } 1122 1123 /* Add the symbols from an object file to the global hash table. ABFD 1124 is the object file. INFO is the linker information. SYMBOL_COUNT 1125 is the number of symbols. SYMBOLS is the list of symbols. */ 1126 1127 static bfd_boolean 1128 generic_link_add_symbol_list (bfd *abfd, 1129 struct bfd_link_info *info, 1130 bfd_size_type symbol_count, 1131 asymbol **symbols) 1132 { 1133 asymbol **pp, **ppend; 1134 1135 pp = symbols; 1136 ppend = symbols + symbol_count; 1137 for (; pp < ppend; pp++) 1138 { 1139 asymbol *p; 1140 1141 p = *pp; 1142 1143 if ((p->flags & (BSF_INDIRECT 1144 | BSF_WARNING 1145 | BSF_GLOBAL 1146 | BSF_CONSTRUCTOR 1147 | BSF_WEAK)) != 0 1148 || bfd_is_und_section (bfd_get_section (p)) 1149 || bfd_is_com_section (bfd_get_section (p)) 1150 || bfd_is_ind_section (bfd_get_section (p))) 1151 { 1152 const char *name; 1153 const char *string; 1154 struct generic_link_hash_entry *h; 1155 struct bfd_link_hash_entry *bh; 1156 1157 string = name = bfd_asymbol_name (p); 1158 if (((p->flags & BSF_INDIRECT) != 0 1159 || bfd_is_ind_section (p->section)) 1160 && pp + 1 < ppend) 1161 { 1162 pp++; 1163 string = bfd_asymbol_name (*pp); 1164 } 1165 else if ((p->flags & BSF_WARNING) != 0 1166 && pp + 1 < ppend) 1167 { 1168 /* The name of P is actually the warning string, and the 1169 next symbol is the one to warn about. */ 1170 pp++; 1171 name = bfd_asymbol_name (*pp); 1172 } 1173 1174 bh = NULL; 1175 if (! (_bfd_generic_link_add_one_symbol 1176 (info, abfd, name, p->flags, bfd_get_section (p), 1177 p->value, string, FALSE, FALSE, &bh))) 1178 return FALSE; 1179 h = (struct generic_link_hash_entry *) bh; 1180 1181 /* If this is a constructor symbol, and the linker didn't do 1182 anything with it, then we want to just pass the symbol 1183 through to the output file. This will happen when 1184 linking with -r. */ 1185 if ((p->flags & BSF_CONSTRUCTOR) != 0 1186 && (h == NULL || h->root.type == bfd_link_hash_new)) 1187 { 1188 p->udata.p = NULL; 1189 continue; 1190 } 1191 1192 /* Save the BFD symbol so that we don't lose any backend 1193 specific information that may be attached to it. We only 1194 want this one if it gives more information than the 1195 existing one; we don't want to replace a defined symbol 1196 with an undefined one. This routine may be called with a 1197 hash table other than the generic hash table, so we only 1198 do this if we are certain that the hash table is a 1199 generic one. */ 1200 if (info->output_bfd->xvec == abfd->xvec) 1201 { 1202 if (h->sym == NULL 1203 || (! bfd_is_und_section (bfd_get_section (p)) 1204 && (! bfd_is_com_section (bfd_get_section (p)) 1205 || bfd_is_und_section (bfd_get_section (h->sym))))) 1206 { 1207 h->sym = p; 1208 /* BSF_OLD_COMMON is a hack to support COFF reloc 1209 reading, and it should go away when the COFF 1210 linker is switched to the new version. */ 1211 if (bfd_is_com_section (bfd_get_section (p))) 1212 p->flags |= BSF_OLD_COMMON; 1213 } 1214 } 1215 1216 /* Store a back pointer from the symbol to the hash 1217 table entry for the benefit of relaxation code until 1218 it gets rewritten to not use asymbol structures. 1219 Setting this is also used to check whether these 1220 symbols were set up by the generic linker. */ 1221 p->udata.p = h; 1222 } 1223 } 1224 1225 return TRUE; 1226 } 1227 1228 /* We use a state table to deal with adding symbols from an object 1229 file. The first index into the state table describes the symbol 1230 from the object file. The second index into the state table is the 1231 type of the symbol in the hash table. */ 1232 1233 /* The symbol from the object file is turned into one of these row 1234 values. */ 1235 1236 enum link_row 1237 { 1238 UNDEF_ROW, /* Undefined. */ 1239 UNDEFW_ROW, /* Weak undefined. */ 1240 DEF_ROW, /* Defined. */ 1241 DEFW_ROW, /* Weak defined. */ 1242 COMMON_ROW, /* Common. */ 1243 INDR_ROW, /* Indirect. */ 1244 WARN_ROW, /* Warning. */ 1245 SET_ROW /* Member of set. */ 1246 }; 1247 1248 /* apparently needed for Hitachi 3050R(HI-UX/WE2)? */ 1249 #undef FAIL 1250 1251 /* The actions to take in the state table. */ 1252 1253 enum link_action 1254 { 1255 FAIL, /* Abort. */ 1256 UND, /* Mark symbol undefined. */ 1257 WEAK, /* Mark symbol weak undefined. */ 1258 DEF, /* Mark symbol defined. */ 1259 DEFW, /* Mark symbol weak defined. */ 1260 COM, /* Mark symbol common. */ 1261 REF, /* Mark defined symbol referenced. */ 1262 CREF, /* Possibly warn about common reference to defined symbol. */ 1263 CDEF, /* Define existing common symbol. */ 1264 NOACT, /* No action. */ 1265 BIG, /* Mark symbol common using largest size. */ 1266 MDEF, /* Multiple definition error. */ 1267 MIND, /* Multiple indirect symbols. */ 1268 IND, /* Make indirect symbol. */ 1269 CIND, /* Make indirect symbol from existing common symbol. */ 1270 SET, /* Add value to set. */ 1271 MWARN, /* Make warning symbol. */ 1272 WARN, /* Warn if referenced, else MWARN. */ 1273 CYCLE, /* Repeat with symbol pointed to. */ 1274 REFC, /* Mark indirect symbol referenced and then CYCLE. */ 1275 WARNC /* Issue warning and then CYCLE. */ 1276 }; 1277 1278 /* The state table itself. The first index is a link_row and the 1279 second index is a bfd_link_hash_type. */ 1280 1281 static const enum link_action link_action[8][8] = 1282 { 1283 /* current\prev new undef undefw def defw com indr warn */ 1284 /* UNDEF_ROW */ {UND, NOACT, UND, REF, REF, NOACT, REFC, WARNC }, 1285 /* UNDEFW_ROW */ {WEAK, NOACT, NOACT, REF, REF, NOACT, REFC, WARNC }, 1286 /* DEF_ROW */ {DEF, DEF, DEF, MDEF, DEF, CDEF, MDEF, CYCLE }, 1287 /* DEFW_ROW */ {DEFW, DEFW, DEFW, NOACT, NOACT, NOACT, NOACT, CYCLE }, 1288 /* COMMON_ROW */ {COM, COM, COM, CREF, COM, BIG, REFC, WARNC }, 1289 /* INDR_ROW */ {IND, IND, IND, MDEF, IND, CIND, MIND, CYCLE }, 1290 /* WARN_ROW */ {MWARN, WARN, WARN, WARN, WARN, WARN, WARN, NOACT }, 1291 /* SET_ROW */ {SET, SET, SET, SET, SET, SET, CYCLE, CYCLE } 1292 }; 1293 1294 /* Most of the entries in the LINK_ACTION table are straightforward, 1295 but a few are somewhat subtle. 1296 1297 A reference to an indirect symbol (UNDEF_ROW/indr or 1298 UNDEFW_ROW/indr) is counted as a reference both to the indirect 1299 symbol and to the symbol the indirect symbol points to. 1300 1301 A reference to a warning symbol (UNDEF_ROW/warn or UNDEFW_ROW/warn) 1302 causes the warning to be issued. 1303 1304 A common definition of an indirect symbol (COMMON_ROW/indr) is 1305 treated as a multiple definition error. Likewise for an indirect 1306 definition of a common symbol (INDR_ROW/com). 1307 1308 An indirect definition of a warning (INDR_ROW/warn) does not cause 1309 the warning to be issued. 1310 1311 If a warning is created for an indirect symbol (WARN_ROW/indr) no 1312 warning is created for the symbol the indirect symbol points to. 1313 1314 Adding an entry to a set does not count as a reference to a set, 1315 and no warning is issued (SET_ROW/warn). */ 1316 1317 /* Return the BFD in which a hash entry has been defined, if known. */ 1318 1319 static bfd * 1320 hash_entry_bfd (struct bfd_link_hash_entry *h) 1321 { 1322 while (h->type == bfd_link_hash_warning) 1323 h = h->u.i.link; 1324 switch (h->type) 1325 { 1326 default: 1327 return NULL; 1328 case bfd_link_hash_undefined: 1329 case bfd_link_hash_undefweak: 1330 return h->u.undef.abfd; 1331 case bfd_link_hash_defined: 1332 case bfd_link_hash_defweak: 1333 return h->u.def.section->owner; 1334 case bfd_link_hash_common: 1335 return h->u.c.p->section->owner; 1336 } 1337 /*NOTREACHED*/ 1338 } 1339 1340 /* Add a symbol to the global hash table. 1341 ABFD is the BFD the symbol comes from. 1342 NAME is the name of the symbol. 1343 FLAGS is the BSF_* bits associated with the symbol. 1344 SECTION is the section in which the symbol is defined; this may be 1345 bfd_und_section_ptr or bfd_com_section_ptr. 1346 VALUE is the value of the symbol, relative to the section. 1347 STRING is used for either an indirect symbol, in which case it is 1348 the name of the symbol to indirect to, or a warning symbol, in 1349 which case it is the warning string. 1350 COPY is TRUE if NAME or STRING must be copied into locally 1351 allocated memory if they need to be saved. 1352 COLLECT is TRUE if we should automatically collect gcc constructor 1353 or destructor names as collect2 does. 1354 HASHP, if not NULL, is a place to store the created hash table 1355 entry; if *HASHP is not NULL, the caller has already looked up 1356 the hash table entry, and stored it in *HASHP. */ 1357 1358 bfd_boolean 1359 _bfd_generic_link_add_one_symbol (struct bfd_link_info *info, 1360 bfd *abfd, 1361 const char *name, 1362 flagword flags, 1363 asection *section, 1364 bfd_vma value, 1365 const char *string, 1366 bfd_boolean copy, 1367 bfd_boolean collect, 1368 struct bfd_link_hash_entry **hashp) 1369 { 1370 enum link_row row; 1371 struct bfd_link_hash_entry *h; 1372 struct bfd_link_hash_entry *inh = NULL; 1373 bfd_boolean cycle; 1374 1375 BFD_ASSERT (section != NULL); 1376 1377 if (bfd_is_ind_section (section) 1378 || (flags & BSF_INDIRECT) != 0) 1379 { 1380 row = INDR_ROW; 1381 /* Create the indirect symbol here. This is for the benefit of 1382 the plugin "notice" function. 1383 STRING is the name of the symbol we want to indirect to. */ 1384 inh = bfd_wrapped_link_hash_lookup (abfd, info, string, TRUE, 1385 copy, FALSE); 1386 if (inh == NULL) 1387 return FALSE; 1388 } 1389 else if ((flags & BSF_WARNING) != 0) 1390 row = WARN_ROW; 1391 else if ((flags & BSF_CONSTRUCTOR) != 0) 1392 row = SET_ROW; 1393 else if (bfd_is_und_section (section)) 1394 { 1395 if ((flags & BSF_WEAK) != 0) 1396 row = UNDEFW_ROW; 1397 else 1398 row = UNDEF_ROW; 1399 } 1400 else if ((flags & BSF_WEAK) != 0) 1401 row = DEFW_ROW; 1402 else if (bfd_is_com_section (section)) 1403 { 1404 row = COMMON_ROW; 1405 if (!bfd_link_relocatable (info) 1406 && name[0] == '_' 1407 && name[1] == '_' 1408 && strcmp (name + (name[2] == '_'), "__gnu_lto_slim") == 0) 1409 _bfd_error_handler 1410 (_("%B: plugin needed to handle lto object"), abfd); 1411 } 1412 else 1413 row = DEF_ROW; 1414 1415 if (hashp != NULL && *hashp != NULL) 1416 h = *hashp; 1417 else 1418 { 1419 if (row == UNDEF_ROW || row == UNDEFW_ROW) 1420 h = bfd_wrapped_link_hash_lookup (abfd, info, name, TRUE, copy, FALSE); 1421 else 1422 h = bfd_link_hash_lookup (info->hash, name, TRUE, copy, FALSE); 1423 if (h == NULL) 1424 { 1425 if (hashp != NULL) 1426 *hashp = NULL; 1427 return FALSE; 1428 } 1429 } 1430 1431 if (info->notice_all 1432 || (info->notice_hash != NULL 1433 && bfd_hash_lookup (info->notice_hash, name, FALSE, FALSE) != NULL)) 1434 { 1435 if (! (*info->callbacks->notice) (info, h, inh, 1436 abfd, section, value, flags)) 1437 return FALSE; 1438 } 1439 1440 if (hashp != NULL) 1441 *hashp = h; 1442 1443 do 1444 { 1445 enum link_action action; 1446 int prev; 1447 1448 prev = h->type; 1449 /* Treat symbols defined by early linker script pass as undefined. */ 1450 if (h->ldscript_def) 1451 prev = bfd_link_hash_undefined; 1452 cycle = FALSE; 1453 action = link_action[(int) row][prev]; 1454 switch (action) 1455 { 1456 case FAIL: 1457 abort (); 1458 1459 case NOACT: 1460 /* Do nothing. */ 1461 break; 1462 1463 case UND: 1464 /* Make a new undefined symbol. */ 1465 h->type = bfd_link_hash_undefined; 1466 h->u.undef.abfd = abfd; 1467 bfd_link_add_undef (info->hash, h); 1468 break; 1469 1470 case WEAK: 1471 /* Make a new weak undefined symbol. */ 1472 h->type = bfd_link_hash_undefweak; 1473 h->u.undef.abfd = abfd; 1474 break; 1475 1476 case CDEF: 1477 /* We have found a definition for a symbol which was 1478 previously common. */ 1479 BFD_ASSERT (h->type == bfd_link_hash_common); 1480 (*info->callbacks->multiple_common) (info, h, abfd, 1481 bfd_link_hash_defined, 0); 1482 /* Fall through. */ 1483 case DEF: 1484 case DEFW: 1485 { 1486 enum bfd_link_hash_type oldtype; 1487 1488 /* Define a symbol. */ 1489 oldtype = h->type; 1490 if (action == DEFW) 1491 h->type = bfd_link_hash_defweak; 1492 else 1493 h->type = bfd_link_hash_defined; 1494 h->u.def.section = section; 1495 h->u.def.value = value; 1496 h->linker_def = 0; 1497 h->ldscript_def = 0; 1498 1499 /* If we have been asked to, we act like collect2 and 1500 identify all functions that might be global 1501 constructors and destructors and pass them up in a 1502 callback. We only do this for certain object file 1503 types, since many object file types can handle this 1504 automatically. */ 1505 if (collect && name[0] == '_') 1506 { 1507 const char *s; 1508 1509 /* A constructor or destructor name starts like this: 1510 _+GLOBAL_[_.$][ID][_.$] where the first [_.$] and 1511 the second are the same character (we accept any 1512 character there, in case a new object file format 1513 comes along with even worse naming restrictions). */ 1514 1515 #define CONS_PREFIX "GLOBAL_" 1516 #define CONS_PREFIX_LEN (sizeof CONS_PREFIX - 1) 1517 1518 s = name + 1; 1519 while (*s == '_') 1520 ++s; 1521 if (s[0] == 'G' && CONST_STRNEQ (s, CONS_PREFIX)) 1522 { 1523 char c; 1524 1525 c = s[CONS_PREFIX_LEN + 1]; 1526 if ((c == 'I' || c == 'D') 1527 && s[CONS_PREFIX_LEN] == s[CONS_PREFIX_LEN + 2]) 1528 { 1529 /* If this is a definition of a symbol which 1530 was previously weakly defined, we are in 1531 trouble. We have already added a 1532 constructor entry for the weak defined 1533 symbol, and now we are trying to add one 1534 for the new symbol. Fortunately, this case 1535 should never arise in practice. */ 1536 if (oldtype == bfd_link_hash_defweak) 1537 abort (); 1538 1539 (*info->callbacks->constructor) (info, c == 'I', 1540 h->root.string, abfd, 1541 section, value); 1542 } 1543 } 1544 } 1545 } 1546 1547 break; 1548 1549 case COM: 1550 /* We have found a common definition for a symbol. */ 1551 if (h->type == bfd_link_hash_new) 1552 bfd_link_add_undef (info->hash, h); 1553 h->type = bfd_link_hash_common; 1554 h->u.c.p = (struct bfd_link_hash_common_entry *) 1555 bfd_hash_allocate (&info->hash->table, 1556 sizeof (struct bfd_link_hash_common_entry)); 1557 if (h->u.c.p == NULL) 1558 return FALSE; 1559 1560 h->u.c.size = value; 1561 1562 /* Select a default alignment based on the size. This may 1563 be overridden by the caller. */ 1564 { 1565 unsigned int power; 1566 1567 power = bfd_log2 (value); 1568 if (power > 4) 1569 power = 4; 1570 h->u.c.p->alignment_power = power; 1571 } 1572 1573 /* The section of a common symbol is only used if the common 1574 symbol is actually allocated. It basically provides a 1575 hook for the linker script to decide which output section 1576 the common symbols should be put in. In most cases, the 1577 section of a common symbol will be bfd_com_section_ptr, 1578 the code here will choose a common symbol section named 1579 "COMMON", and the linker script will contain *(COMMON) in 1580 the appropriate place. A few targets use separate common 1581 sections for small symbols, and they require special 1582 handling. */ 1583 if (section == bfd_com_section_ptr) 1584 { 1585 h->u.c.p->section = bfd_make_section_old_way (abfd, "COMMON"); 1586 h->u.c.p->section->flags |= SEC_ALLOC; 1587 } 1588 else if (section->owner != abfd) 1589 { 1590 h->u.c.p->section = bfd_make_section_old_way (abfd, 1591 section->name); 1592 h->u.c.p->section->flags |= SEC_ALLOC; 1593 } 1594 else 1595 h->u.c.p->section = section; 1596 h->linker_def = 0; 1597 h->ldscript_def = 0; 1598 break; 1599 1600 case REF: 1601 /* A reference to a defined symbol. */ 1602 if (h->u.undef.next == NULL && info->hash->undefs_tail != h) 1603 h->u.undef.next = h; 1604 break; 1605 1606 case BIG: 1607 /* We have found a common definition for a symbol which 1608 already had a common definition. Use the maximum of the 1609 two sizes, and use the section required by the larger symbol. */ 1610 BFD_ASSERT (h->type == bfd_link_hash_common); 1611 (*info->callbacks->multiple_common) (info, h, abfd, 1612 bfd_link_hash_common, value); 1613 if (value > h->u.c.size) 1614 { 1615 unsigned int power; 1616 1617 h->u.c.size = value; 1618 1619 /* Select a default alignment based on the size. This may 1620 be overridden by the caller. */ 1621 power = bfd_log2 (value); 1622 if (power > 4) 1623 power = 4; 1624 h->u.c.p->alignment_power = power; 1625 1626 /* Some systems have special treatment for small commons, 1627 hence we want to select the section used by the larger 1628 symbol. This makes sure the symbol does not go in a 1629 small common section if it is now too large. */ 1630 if (section == bfd_com_section_ptr) 1631 { 1632 h->u.c.p->section 1633 = bfd_make_section_old_way (abfd, "COMMON"); 1634 h->u.c.p->section->flags |= SEC_ALLOC; 1635 } 1636 else if (section->owner != abfd) 1637 { 1638 h->u.c.p->section 1639 = bfd_make_section_old_way (abfd, section->name); 1640 h->u.c.p->section->flags |= SEC_ALLOC; 1641 } 1642 else 1643 h->u.c.p->section = section; 1644 } 1645 break; 1646 1647 case CREF: 1648 /* We have found a common definition for a symbol which 1649 was already defined. */ 1650 (*info->callbacks->multiple_common) (info, h, abfd, 1651 bfd_link_hash_common, value); 1652 break; 1653 1654 case MIND: 1655 /* Multiple indirect symbols. This is OK if they both point 1656 to the same symbol. */ 1657 if (strcmp (h->u.i.link->root.string, string) == 0) 1658 break; 1659 /* Fall through. */ 1660 case MDEF: 1661 /* Handle a multiple definition. */ 1662 (*info->callbacks->multiple_definition) (info, h, 1663 abfd, section, value); 1664 break; 1665 1666 case CIND: 1667 /* Create an indirect symbol from an existing common symbol. */ 1668 BFD_ASSERT (h->type == bfd_link_hash_common); 1669 (*info->callbacks->multiple_common) (info, h, abfd, 1670 bfd_link_hash_indirect, 0); 1671 /* Fall through. */ 1672 case IND: 1673 if (inh->type == bfd_link_hash_indirect 1674 && inh->u.i.link == h) 1675 { 1676 _bfd_error_handler 1677 /* xgettext:c-format */ 1678 (_("%B: indirect symbol `%s' to `%s' is a loop"), 1679 abfd, name, string); 1680 bfd_set_error (bfd_error_invalid_operation); 1681 return FALSE; 1682 } 1683 if (inh->type == bfd_link_hash_new) 1684 { 1685 inh->type = bfd_link_hash_undefined; 1686 inh->u.undef.abfd = abfd; 1687 bfd_link_add_undef (info->hash, inh); 1688 } 1689 1690 /* If the indirect symbol has been referenced, we need to 1691 push the reference down to the symbol we are referencing. */ 1692 if (h->type != bfd_link_hash_new) 1693 { 1694 /* ??? If inh->type == bfd_link_hash_undefweak this 1695 converts inh to bfd_link_hash_undefined. */ 1696 row = UNDEF_ROW; 1697 cycle = TRUE; 1698 } 1699 1700 h->type = bfd_link_hash_indirect; 1701 h->u.i.link = inh; 1702 /* Not setting h = h->u.i.link here means that when cycle is 1703 set above we'll always go to REFC, and then cycle again 1704 to the indirected symbol. This means that any successful 1705 change of an existing symbol to indirect counts as a 1706 reference. ??? That may not be correct when the existing 1707 symbol was defweak. */ 1708 break; 1709 1710 case SET: 1711 /* Add an entry to a set. */ 1712 (*info->callbacks->add_to_set) (info, h, BFD_RELOC_CTOR, 1713 abfd, section, value); 1714 break; 1715 1716 case WARNC: 1717 /* Issue a warning and cycle, except when the reference is 1718 in LTO IR. */ 1719 if (h->u.i.warning != NULL 1720 && (abfd->flags & BFD_PLUGIN) == 0) 1721 { 1722 (*info->callbacks->warning) (info, h->u.i.warning, 1723 h->root.string, abfd, NULL, 0); 1724 /* Only issue a warning once. */ 1725 h->u.i.warning = NULL; 1726 } 1727 /* Fall through. */ 1728 case CYCLE: 1729 /* Try again with the referenced symbol. */ 1730 h = h->u.i.link; 1731 cycle = TRUE; 1732 break; 1733 1734 case REFC: 1735 /* A reference to an indirect symbol. */ 1736 if (h->u.undef.next == NULL && info->hash->undefs_tail != h) 1737 h->u.undef.next = h; 1738 h = h->u.i.link; 1739 cycle = TRUE; 1740 break; 1741 1742 case WARN: 1743 /* Warn if this symbol has been referenced already from non-IR, 1744 otherwise add a warning. */ 1745 if ((!info->lto_plugin_active 1746 && (h->u.undef.next != NULL || info->hash->undefs_tail == h)) 1747 || h->non_ir_ref_regular 1748 || h->non_ir_ref_dynamic) 1749 { 1750 (*info->callbacks->warning) (info, string, h->root.string, 1751 hash_entry_bfd (h), NULL, 0); 1752 break; 1753 } 1754 /* Fall through. */ 1755 case MWARN: 1756 /* Make a warning symbol. */ 1757 { 1758 struct bfd_link_hash_entry *sub; 1759 1760 /* STRING is the warning to give. */ 1761 sub = ((struct bfd_link_hash_entry *) 1762 ((*info->hash->table.newfunc) 1763 (NULL, &info->hash->table, h->root.string))); 1764 if (sub == NULL) 1765 return FALSE; 1766 *sub = *h; 1767 sub->type = bfd_link_hash_warning; 1768 sub->u.i.link = h; 1769 if (! copy) 1770 sub->u.i.warning = string; 1771 else 1772 { 1773 char *w; 1774 size_t len = strlen (string) + 1; 1775 1776 w = (char *) bfd_hash_allocate (&info->hash->table, len); 1777 if (w == NULL) 1778 return FALSE; 1779 memcpy (w, string, len); 1780 sub->u.i.warning = w; 1781 } 1782 1783 bfd_hash_replace (&info->hash->table, 1784 (struct bfd_hash_entry *) h, 1785 (struct bfd_hash_entry *) sub); 1786 if (hashp != NULL) 1787 *hashp = sub; 1788 } 1789 break; 1790 } 1791 } 1792 while (cycle); 1793 1794 return TRUE; 1795 } 1796 1797 /* Generic final link routine. */ 1798 1799 bfd_boolean 1800 _bfd_generic_final_link (bfd *abfd, struct bfd_link_info *info) 1801 { 1802 bfd *sub; 1803 asection *o; 1804 struct bfd_link_order *p; 1805 size_t outsymalloc; 1806 struct generic_write_global_symbol_info wginfo; 1807 1808 bfd_get_outsymbols (abfd) = NULL; 1809 bfd_get_symcount (abfd) = 0; 1810 outsymalloc = 0; 1811 1812 /* Mark all sections which will be included in the output file. */ 1813 for (o = abfd->sections; o != NULL; o = o->next) 1814 for (p = o->map_head.link_order; p != NULL; p = p->next) 1815 if (p->type == bfd_indirect_link_order) 1816 p->u.indirect.section->linker_mark = TRUE; 1817 1818 /* Build the output symbol table. */ 1819 for (sub = info->input_bfds; sub != NULL; sub = sub->link.next) 1820 if (! _bfd_generic_link_output_symbols (abfd, sub, info, &outsymalloc)) 1821 return FALSE; 1822 1823 /* Accumulate the global symbols. */ 1824 wginfo.info = info; 1825 wginfo.output_bfd = abfd; 1826 wginfo.psymalloc = &outsymalloc; 1827 _bfd_generic_link_hash_traverse (_bfd_generic_hash_table (info), 1828 _bfd_generic_link_write_global_symbol, 1829 &wginfo); 1830 1831 /* Make sure we have a trailing NULL pointer on OUTSYMBOLS. We 1832 shouldn't really need one, since we have SYMCOUNT, but some old 1833 code still expects one. */ 1834 if (! generic_add_output_symbol (abfd, &outsymalloc, NULL)) 1835 return FALSE; 1836 1837 if (bfd_link_relocatable (info)) 1838 { 1839 /* Allocate space for the output relocs for each section. */ 1840 for (o = abfd->sections; o != NULL; o = o->next) 1841 { 1842 o->reloc_count = 0; 1843 for (p = o->map_head.link_order; p != NULL; p = p->next) 1844 { 1845 if (p->type == bfd_section_reloc_link_order 1846 || p->type == bfd_symbol_reloc_link_order) 1847 ++o->reloc_count; 1848 else if (p->type == bfd_indirect_link_order) 1849 { 1850 asection *input_section; 1851 bfd *input_bfd; 1852 long relsize; 1853 arelent **relocs; 1854 asymbol **symbols; 1855 long reloc_count; 1856 1857 input_section = p->u.indirect.section; 1858 input_bfd = input_section->owner; 1859 relsize = bfd_get_reloc_upper_bound (input_bfd, 1860 input_section); 1861 if (relsize < 0) 1862 return FALSE; 1863 relocs = (arelent **) bfd_malloc (relsize); 1864 if (!relocs && relsize != 0) 1865 return FALSE; 1866 symbols = _bfd_generic_link_get_symbols (input_bfd); 1867 reloc_count = bfd_canonicalize_reloc (input_bfd, 1868 input_section, 1869 relocs, 1870 symbols); 1871 free (relocs); 1872 if (reloc_count < 0) 1873 return FALSE; 1874 BFD_ASSERT ((unsigned long) reloc_count 1875 == input_section->reloc_count); 1876 o->reloc_count += reloc_count; 1877 } 1878 } 1879 if (o->reloc_count > 0) 1880 { 1881 bfd_size_type amt; 1882 1883 amt = o->reloc_count; 1884 amt *= sizeof (arelent *); 1885 o->orelocation = (struct reloc_cache_entry **) bfd_alloc (abfd, amt); 1886 if (!o->orelocation) 1887 return FALSE; 1888 o->flags |= SEC_RELOC; 1889 /* Reset the count so that it can be used as an index 1890 when putting in the output relocs. */ 1891 o->reloc_count = 0; 1892 } 1893 } 1894 } 1895 1896 /* Handle all the link order information for the sections. */ 1897 for (o = abfd->sections; o != NULL; o = o->next) 1898 { 1899 for (p = o->map_head.link_order; p != NULL; p = p->next) 1900 { 1901 switch (p->type) 1902 { 1903 case bfd_section_reloc_link_order: 1904 case bfd_symbol_reloc_link_order: 1905 if (! _bfd_generic_reloc_link_order (abfd, info, o, p)) 1906 return FALSE; 1907 break; 1908 case bfd_indirect_link_order: 1909 if (! default_indirect_link_order (abfd, info, o, p, TRUE)) 1910 return FALSE; 1911 break; 1912 default: 1913 if (! _bfd_default_link_order (abfd, info, o, p)) 1914 return FALSE; 1915 break; 1916 } 1917 } 1918 } 1919 1920 return TRUE; 1921 } 1922 1923 /* Add an output symbol to the output BFD. */ 1924 1925 static bfd_boolean 1926 generic_add_output_symbol (bfd *output_bfd, size_t *psymalloc, asymbol *sym) 1927 { 1928 if (bfd_get_symcount (output_bfd) >= *psymalloc) 1929 { 1930 asymbol **newsyms; 1931 bfd_size_type amt; 1932 1933 if (*psymalloc == 0) 1934 *psymalloc = 124; 1935 else 1936 *psymalloc *= 2; 1937 amt = *psymalloc; 1938 amt *= sizeof (asymbol *); 1939 newsyms = (asymbol **) bfd_realloc (bfd_get_outsymbols (output_bfd), amt); 1940 if (newsyms == NULL) 1941 return FALSE; 1942 bfd_get_outsymbols (output_bfd) = newsyms; 1943 } 1944 1945 bfd_get_outsymbols (output_bfd) [bfd_get_symcount (output_bfd)] = sym; 1946 if (sym != NULL) 1947 ++ bfd_get_symcount (output_bfd); 1948 1949 return TRUE; 1950 } 1951 1952 /* Handle the symbols for an input BFD. */ 1953 1954 bfd_boolean 1955 _bfd_generic_link_output_symbols (bfd *output_bfd, 1956 bfd *input_bfd, 1957 struct bfd_link_info *info, 1958 size_t *psymalloc) 1959 { 1960 asymbol **sym_ptr; 1961 asymbol **sym_end; 1962 1963 if (!bfd_generic_link_read_symbols (input_bfd)) 1964 return FALSE; 1965 1966 /* Create a filename symbol if we are supposed to. */ 1967 if (info->create_object_symbols_section != NULL) 1968 { 1969 asection *sec; 1970 1971 for (sec = input_bfd->sections; sec != NULL; sec = sec->next) 1972 { 1973 if (sec->output_section == info->create_object_symbols_section) 1974 { 1975 asymbol *newsym; 1976 1977 newsym = bfd_make_empty_symbol (input_bfd); 1978 if (!newsym) 1979 return FALSE; 1980 newsym->name = input_bfd->filename; 1981 newsym->value = 0; 1982 newsym->flags = BSF_LOCAL | BSF_FILE; 1983 newsym->section = sec; 1984 1985 if (! generic_add_output_symbol (output_bfd, psymalloc, 1986 newsym)) 1987 return FALSE; 1988 1989 break; 1990 } 1991 } 1992 } 1993 1994 /* Adjust the values of the globally visible symbols, and write out 1995 local symbols. */ 1996 sym_ptr = _bfd_generic_link_get_symbols (input_bfd); 1997 sym_end = sym_ptr + _bfd_generic_link_get_symcount (input_bfd); 1998 for (; sym_ptr < sym_end; sym_ptr++) 1999 { 2000 asymbol *sym; 2001 struct generic_link_hash_entry *h; 2002 bfd_boolean output; 2003 2004 h = NULL; 2005 sym = *sym_ptr; 2006 if ((sym->flags & (BSF_INDIRECT 2007 | BSF_WARNING 2008 | BSF_GLOBAL 2009 | BSF_CONSTRUCTOR 2010 | BSF_WEAK)) != 0 2011 || bfd_is_und_section (bfd_get_section (sym)) 2012 || bfd_is_com_section (bfd_get_section (sym)) 2013 || bfd_is_ind_section (bfd_get_section (sym))) 2014 { 2015 if (sym->udata.p != NULL) 2016 h = (struct generic_link_hash_entry *) sym->udata.p; 2017 else if ((sym->flags & BSF_CONSTRUCTOR) != 0) 2018 { 2019 /* This case normally means that the main linker code 2020 deliberately ignored this constructor symbol. We 2021 should just pass it through. This will screw up if 2022 the constructor symbol is from a different, 2023 non-generic, object file format, but the case will 2024 only arise when linking with -r, which will probably 2025 fail anyhow, since there will be no way to represent 2026 the relocs in the output format being used. */ 2027 h = NULL; 2028 } 2029 else if (bfd_is_und_section (bfd_get_section (sym))) 2030 h = ((struct generic_link_hash_entry *) 2031 bfd_wrapped_link_hash_lookup (output_bfd, info, 2032 bfd_asymbol_name (sym), 2033 FALSE, FALSE, TRUE)); 2034 else 2035 h = _bfd_generic_link_hash_lookup (_bfd_generic_hash_table (info), 2036 bfd_asymbol_name (sym), 2037 FALSE, FALSE, TRUE); 2038 2039 if (h != NULL) 2040 { 2041 /* Force all references to this symbol to point to 2042 the same area in memory. It is possible that 2043 this routine will be called with a hash table 2044 other than a generic hash table, so we double 2045 check that. */ 2046 if (info->output_bfd->xvec == input_bfd->xvec) 2047 { 2048 if (h->sym != NULL) 2049 *sym_ptr = sym = h->sym; 2050 } 2051 2052 switch (h->root.type) 2053 { 2054 default: 2055 case bfd_link_hash_new: 2056 abort (); 2057 case bfd_link_hash_undefined: 2058 break; 2059 case bfd_link_hash_undefweak: 2060 sym->flags |= BSF_WEAK; 2061 break; 2062 case bfd_link_hash_indirect: 2063 h = (struct generic_link_hash_entry *) h->root.u.i.link; 2064 /* fall through */ 2065 case bfd_link_hash_defined: 2066 sym->flags |= BSF_GLOBAL; 2067 sym->flags &=~ (BSF_WEAK | BSF_CONSTRUCTOR); 2068 sym->value = h->root.u.def.value; 2069 sym->section = h->root.u.def.section; 2070 break; 2071 case bfd_link_hash_defweak: 2072 sym->flags |= BSF_WEAK; 2073 sym->flags &=~ BSF_CONSTRUCTOR; 2074 sym->value = h->root.u.def.value; 2075 sym->section = h->root.u.def.section; 2076 break; 2077 case bfd_link_hash_common: 2078 sym->value = h->root.u.c.size; 2079 sym->flags |= BSF_GLOBAL; 2080 if (! bfd_is_com_section (sym->section)) 2081 { 2082 BFD_ASSERT (bfd_is_und_section (sym->section)); 2083 sym->section = bfd_com_section_ptr; 2084 } 2085 /* We do not set the section of the symbol to 2086 h->root.u.c.p->section. That value was saved so 2087 that we would know where to allocate the symbol 2088 if it was defined. In this case the type is 2089 still bfd_link_hash_common, so we did not define 2090 it, so we do not want to use that section. */ 2091 break; 2092 } 2093 } 2094 } 2095 2096 /* This switch is straight from the old code in 2097 write_file_locals in ldsym.c. */ 2098 if (info->strip == strip_all 2099 || (info->strip == strip_some 2100 && bfd_hash_lookup (info->keep_hash, bfd_asymbol_name (sym), 2101 FALSE, FALSE) == NULL)) 2102 output = FALSE; 2103 else if ((sym->flags & (BSF_GLOBAL | BSF_WEAK | BSF_GNU_UNIQUE)) != 0) 2104 { 2105 /* If this symbol is marked as occurring now, rather 2106 than at the end, output it now. This is used for 2107 COFF C_EXT FCN symbols. FIXME: There must be a 2108 better way. */ 2109 if (bfd_asymbol_bfd (sym) == input_bfd 2110 && (sym->flags & BSF_NOT_AT_END) != 0) 2111 output = TRUE; 2112 else 2113 output = FALSE; 2114 } 2115 else if (bfd_is_ind_section (sym->section)) 2116 output = FALSE; 2117 else if ((sym->flags & BSF_DEBUGGING) != 0) 2118 { 2119 if (info->strip == strip_none) 2120 output = TRUE; 2121 else 2122 output = FALSE; 2123 } 2124 else if (bfd_is_und_section (sym->section) 2125 || bfd_is_com_section (sym->section)) 2126 output = FALSE; 2127 else if ((sym->flags & BSF_LOCAL) != 0) 2128 { 2129 if ((sym->flags & BSF_WARNING) != 0) 2130 output = FALSE; 2131 else 2132 { 2133 switch (info->discard) 2134 { 2135 default: 2136 case discard_all: 2137 output = FALSE; 2138 break; 2139 case discard_sec_merge: 2140 output = TRUE; 2141 if (bfd_link_relocatable (info) 2142 || ! (sym->section->flags & SEC_MERGE)) 2143 break; 2144 /* FALLTHROUGH */ 2145 case discard_l: 2146 if (bfd_is_local_label (input_bfd, sym)) 2147 output = FALSE; 2148 else 2149 output = TRUE; 2150 break; 2151 case discard_none: 2152 output = TRUE; 2153 break; 2154 } 2155 } 2156 } 2157 else if ((sym->flags & BSF_CONSTRUCTOR)) 2158 { 2159 if (info->strip != strip_all) 2160 output = TRUE; 2161 else 2162 output = FALSE; 2163 } 2164 else if (sym->flags == 0 2165 && (sym->section->owner->flags & BFD_PLUGIN) != 0) 2166 /* LTO doesn't set symbol information. We get here with the 2167 generic linker for a symbol that was "common" but no longer 2168 needs to be global. */ 2169 output = FALSE; 2170 else 2171 abort (); 2172 2173 /* If this symbol is in a section which is not being included 2174 in the output file, then we don't want to output the 2175 symbol. */ 2176 if (!bfd_is_abs_section (sym->section) 2177 && bfd_section_removed_from_list (output_bfd, 2178 sym->section->output_section)) 2179 output = FALSE; 2180 2181 if (output) 2182 { 2183 if (! generic_add_output_symbol (output_bfd, psymalloc, sym)) 2184 return FALSE; 2185 if (h != NULL) 2186 h->written = TRUE; 2187 } 2188 } 2189 2190 return TRUE; 2191 } 2192 2193 /* Set the section and value of a generic BFD symbol based on a linker 2194 hash table entry. */ 2195 2196 static void 2197 set_symbol_from_hash (asymbol *sym, struct bfd_link_hash_entry *h) 2198 { 2199 switch (h->type) 2200 { 2201 default: 2202 abort (); 2203 break; 2204 case bfd_link_hash_new: 2205 /* This can happen when a constructor symbol is seen but we are 2206 not building constructors. */ 2207 if (sym->section != NULL) 2208 { 2209 BFD_ASSERT ((sym->flags & BSF_CONSTRUCTOR) != 0); 2210 } 2211 else 2212 { 2213 sym->flags |= BSF_CONSTRUCTOR; 2214 sym->section = bfd_abs_section_ptr; 2215 sym->value = 0; 2216 } 2217 break; 2218 case bfd_link_hash_undefined: 2219 sym->section = bfd_und_section_ptr; 2220 sym->value = 0; 2221 break; 2222 case bfd_link_hash_undefweak: 2223 sym->section = bfd_und_section_ptr; 2224 sym->value = 0; 2225 sym->flags |= BSF_WEAK; 2226 break; 2227 case bfd_link_hash_defined: 2228 sym->section = h->u.def.section; 2229 sym->value = h->u.def.value; 2230 break; 2231 case bfd_link_hash_defweak: 2232 sym->flags |= BSF_WEAK; 2233 sym->section = h->u.def.section; 2234 sym->value = h->u.def.value; 2235 break; 2236 case bfd_link_hash_common: 2237 sym->value = h->u.c.size; 2238 if (sym->section == NULL) 2239 sym->section = bfd_com_section_ptr; 2240 else if (! bfd_is_com_section (sym->section)) 2241 { 2242 BFD_ASSERT (bfd_is_und_section (sym->section)); 2243 sym->section = bfd_com_section_ptr; 2244 } 2245 /* Do not set the section; see _bfd_generic_link_output_symbols. */ 2246 break; 2247 case bfd_link_hash_indirect: 2248 case bfd_link_hash_warning: 2249 /* FIXME: What should we do here? */ 2250 break; 2251 } 2252 } 2253 2254 /* Write out a global symbol, if it hasn't already been written out. 2255 This is called for each symbol in the hash table. */ 2256 2257 bfd_boolean 2258 _bfd_generic_link_write_global_symbol (struct generic_link_hash_entry *h, 2259 void *data) 2260 { 2261 struct generic_write_global_symbol_info *wginfo = 2262 (struct generic_write_global_symbol_info *) data; 2263 asymbol *sym; 2264 2265 if (h->written) 2266 return TRUE; 2267 2268 h->written = TRUE; 2269 2270 if (wginfo->info->strip == strip_all 2271 || (wginfo->info->strip == strip_some 2272 && bfd_hash_lookup (wginfo->info->keep_hash, h->root.root.string, 2273 FALSE, FALSE) == NULL)) 2274 return TRUE; 2275 2276 if (h->sym != NULL) 2277 sym = h->sym; 2278 else 2279 { 2280 sym = bfd_make_empty_symbol (wginfo->output_bfd); 2281 if (!sym) 2282 return FALSE; 2283 sym->name = h->root.root.string; 2284 sym->flags = 0; 2285 } 2286 2287 set_symbol_from_hash (sym, &h->root); 2288 2289 sym->flags |= BSF_GLOBAL; 2290 2291 if (! generic_add_output_symbol (wginfo->output_bfd, wginfo->psymalloc, 2292 sym)) 2293 { 2294 /* FIXME: No way to return failure. */ 2295 abort (); 2296 } 2297 2298 return TRUE; 2299 } 2300 2301 /* Create a relocation. */ 2302 2303 bfd_boolean 2304 _bfd_generic_reloc_link_order (bfd *abfd, 2305 struct bfd_link_info *info, 2306 asection *sec, 2307 struct bfd_link_order *link_order) 2308 { 2309 arelent *r; 2310 2311 if (! bfd_link_relocatable (info)) 2312 abort (); 2313 if (sec->orelocation == NULL) 2314 abort (); 2315 2316 r = (arelent *) bfd_alloc (abfd, sizeof (arelent)); 2317 if (r == NULL) 2318 return FALSE; 2319 2320 r->address = link_order->offset; 2321 r->howto = bfd_reloc_type_lookup (abfd, link_order->u.reloc.p->reloc); 2322 if (r->howto == 0) 2323 { 2324 bfd_set_error (bfd_error_bad_value); 2325 return FALSE; 2326 } 2327 2328 /* Get the symbol to use for the relocation. */ 2329 if (link_order->type == bfd_section_reloc_link_order) 2330 r->sym_ptr_ptr = link_order->u.reloc.p->u.section->symbol_ptr_ptr; 2331 else 2332 { 2333 struct generic_link_hash_entry *h; 2334 2335 h = ((struct generic_link_hash_entry *) 2336 bfd_wrapped_link_hash_lookup (abfd, info, 2337 link_order->u.reloc.p->u.name, 2338 FALSE, FALSE, TRUE)); 2339 if (h == NULL 2340 || ! h->written) 2341 { 2342 (*info->callbacks->unattached_reloc) 2343 (info, link_order->u.reloc.p->u.name, NULL, NULL, 0); 2344 bfd_set_error (bfd_error_bad_value); 2345 return FALSE; 2346 } 2347 r->sym_ptr_ptr = &h->sym; 2348 } 2349 2350 /* If this is an inplace reloc, write the addend to the object file. 2351 Otherwise, store it in the reloc addend. */ 2352 if (! r->howto->partial_inplace) 2353 r->addend = link_order->u.reloc.p->addend; 2354 else 2355 { 2356 bfd_size_type size; 2357 bfd_reloc_status_type rstat; 2358 bfd_byte *buf; 2359 bfd_boolean ok; 2360 file_ptr loc; 2361 2362 size = bfd_get_reloc_size (r->howto); 2363 buf = (bfd_byte *) bfd_zmalloc (size); 2364 if (buf == NULL && size != 0) 2365 return FALSE; 2366 rstat = _bfd_relocate_contents (r->howto, abfd, 2367 (bfd_vma) link_order->u.reloc.p->addend, 2368 buf); 2369 switch (rstat) 2370 { 2371 case bfd_reloc_ok: 2372 break; 2373 default: 2374 case bfd_reloc_outofrange: 2375 abort (); 2376 case bfd_reloc_overflow: 2377 (*info->callbacks->reloc_overflow) 2378 (info, NULL, 2379 (link_order->type == bfd_section_reloc_link_order 2380 ? bfd_section_name (abfd, link_order->u.reloc.p->u.section) 2381 : link_order->u.reloc.p->u.name), 2382 r->howto->name, link_order->u.reloc.p->addend, 2383 NULL, NULL, 0); 2384 break; 2385 } 2386 loc = link_order->offset * bfd_octets_per_byte (abfd); 2387 ok = bfd_set_section_contents (abfd, sec, buf, loc, size); 2388 free (buf); 2389 if (! ok) 2390 return FALSE; 2391 2392 r->addend = 0; 2393 } 2394 2395 sec->orelocation[sec->reloc_count] = r; 2396 ++sec->reloc_count; 2397 2398 return TRUE; 2399 } 2400 2401 /* Allocate a new link_order for a section. */ 2402 2403 struct bfd_link_order * 2404 bfd_new_link_order (bfd *abfd, asection *section) 2405 { 2406 bfd_size_type amt = sizeof (struct bfd_link_order); 2407 struct bfd_link_order *new_lo; 2408 2409 new_lo = (struct bfd_link_order *) bfd_zalloc (abfd, amt); 2410 if (!new_lo) 2411 return NULL; 2412 2413 new_lo->type = bfd_undefined_link_order; 2414 2415 if (section->map_tail.link_order != NULL) 2416 section->map_tail.link_order->next = new_lo; 2417 else 2418 section->map_head.link_order = new_lo; 2419 section->map_tail.link_order = new_lo; 2420 2421 return new_lo; 2422 } 2423 2424 /* Default link order processing routine. Note that we can not handle 2425 the reloc_link_order types here, since they depend upon the details 2426 of how the particular backends generates relocs. */ 2427 2428 bfd_boolean 2429 _bfd_default_link_order (bfd *abfd, 2430 struct bfd_link_info *info, 2431 asection *sec, 2432 struct bfd_link_order *link_order) 2433 { 2434 switch (link_order->type) 2435 { 2436 case bfd_undefined_link_order: 2437 case bfd_section_reloc_link_order: 2438 case bfd_symbol_reloc_link_order: 2439 default: 2440 abort (); 2441 case bfd_indirect_link_order: 2442 return default_indirect_link_order (abfd, info, sec, link_order, 2443 FALSE); 2444 case bfd_data_link_order: 2445 return default_data_link_order (abfd, info, sec, link_order); 2446 } 2447 } 2448 2449 /* Default routine to handle a bfd_data_link_order. */ 2450 2451 static bfd_boolean 2452 default_data_link_order (bfd *abfd, 2453 struct bfd_link_info *info ATTRIBUTE_UNUSED, 2454 asection *sec, 2455 struct bfd_link_order *link_order) 2456 { 2457 bfd_size_type size; 2458 size_t fill_size; 2459 bfd_byte *fill; 2460 file_ptr loc; 2461 bfd_boolean result; 2462 2463 BFD_ASSERT ((sec->flags & SEC_HAS_CONTENTS) != 0); 2464 2465 size = link_order->size; 2466 if (size == 0) 2467 return TRUE; 2468 2469 fill = link_order->u.data.contents; 2470 fill_size = link_order->u.data.size; 2471 if (fill_size == 0) 2472 { 2473 fill = abfd->arch_info->fill (size, bfd_big_endian (abfd), 2474 (sec->flags & SEC_CODE) != 0); 2475 if (fill == NULL) 2476 return FALSE; 2477 } 2478 else if (fill_size < size) 2479 { 2480 bfd_byte *p; 2481 fill = (bfd_byte *) bfd_malloc (size); 2482 if (fill == NULL) 2483 return FALSE; 2484 p = fill; 2485 if (fill_size == 1) 2486 memset (p, (int) link_order->u.data.contents[0], (size_t) size); 2487 else 2488 { 2489 do 2490 { 2491 memcpy (p, link_order->u.data.contents, fill_size); 2492 p += fill_size; 2493 size -= fill_size; 2494 } 2495 while (size >= fill_size); 2496 if (size != 0) 2497 memcpy (p, link_order->u.data.contents, (size_t) size); 2498 size = link_order->size; 2499 } 2500 } 2501 2502 loc = link_order->offset * bfd_octets_per_byte (abfd); 2503 result = bfd_set_section_contents (abfd, sec, fill, loc, size); 2504 2505 if (fill != link_order->u.data.contents) 2506 free (fill); 2507 return result; 2508 } 2509 2510 /* Default routine to handle a bfd_indirect_link_order. */ 2511 2512 static bfd_boolean 2513 default_indirect_link_order (bfd *output_bfd, 2514 struct bfd_link_info *info, 2515 asection *output_section, 2516 struct bfd_link_order *link_order, 2517 bfd_boolean generic_linker) 2518 { 2519 asection *input_section; 2520 bfd *input_bfd; 2521 bfd_byte *contents = NULL; 2522 bfd_byte *new_contents; 2523 bfd_size_type sec_size; 2524 file_ptr loc; 2525 2526 BFD_ASSERT ((output_section->flags & SEC_HAS_CONTENTS) != 0); 2527 2528 input_section = link_order->u.indirect.section; 2529 input_bfd = input_section->owner; 2530 if (input_section->size == 0) 2531 return TRUE; 2532 2533 BFD_ASSERT (input_section->output_section == output_section); 2534 BFD_ASSERT (input_section->output_offset == link_order->offset); 2535 BFD_ASSERT (input_section->size == link_order->size); 2536 2537 if (bfd_link_relocatable (info) 2538 && input_section->reloc_count > 0 2539 && output_section->orelocation == NULL) 2540 { 2541 /* Space has not been allocated for the output relocations. 2542 This can happen when we are called by a specific backend 2543 because somebody is attempting to link together different 2544 types of object files. Handling this case correctly is 2545 difficult, and sometimes impossible. */ 2546 _bfd_error_handler 2547 /* xgettext:c-format */ 2548 (_("Attempt to do relocatable link with %s input and %s output"), 2549 bfd_get_target (input_bfd), bfd_get_target (output_bfd)); 2550 bfd_set_error (bfd_error_wrong_format); 2551 return FALSE; 2552 } 2553 2554 if (! generic_linker) 2555 { 2556 asymbol **sympp; 2557 asymbol **symppend; 2558 2559 /* Get the canonical symbols. The generic linker will always 2560 have retrieved them by this point, but we are being called by 2561 a specific linker, presumably because we are linking 2562 different types of object files together. */ 2563 if (!bfd_generic_link_read_symbols (input_bfd)) 2564 return FALSE; 2565 2566 /* Since we have been called by a specific linker, rather than 2567 the generic linker, the values of the symbols will not be 2568 right. They will be the values as seen in the input file, 2569 not the values of the final link. We need to fix them up 2570 before we can relocate the section. */ 2571 sympp = _bfd_generic_link_get_symbols (input_bfd); 2572 symppend = sympp + _bfd_generic_link_get_symcount (input_bfd); 2573 for (; sympp < symppend; sympp++) 2574 { 2575 asymbol *sym; 2576 struct bfd_link_hash_entry *h; 2577 2578 sym = *sympp; 2579 2580 if ((sym->flags & (BSF_INDIRECT 2581 | BSF_WARNING 2582 | BSF_GLOBAL 2583 | BSF_CONSTRUCTOR 2584 | BSF_WEAK)) != 0 2585 || bfd_is_und_section (bfd_get_section (sym)) 2586 || bfd_is_com_section (bfd_get_section (sym)) 2587 || bfd_is_ind_section (bfd_get_section (sym))) 2588 { 2589 /* sym->udata may have been set by 2590 generic_link_add_symbol_list. */ 2591 if (sym->udata.p != NULL) 2592 h = (struct bfd_link_hash_entry *) sym->udata.p; 2593 else if (bfd_is_und_section (bfd_get_section (sym))) 2594 h = bfd_wrapped_link_hash_lookup (output_bfd, info, 2595 bfd_asymbol_name (sym), 2596 FALSE, FALSE, TRUE); 2597 else 2598 h = bfd_link_hash_lookup (info->hash, 2599 bfd_asymbol_name (sym), 2600 FALSE, FALSE, TRUE); 2601 if (h != NULL) 2602 set_symbol_from_hash (sym, h); 2603 } 2604 } 2605 } 2606 2607 if ((output_section->flags & (SEC_GROUP | SEC_LINKER_CREATED)) == SEC_GROUP 2608 && input_section->size != 0) 2609 { 2610 /* Group section contents are set by bfd_elf_set_group_contents. */ 2611 if (!output_bfd->output_has_begun) 2612 { 2613 /* FIXME: This hack ensures bfd_elf_set_group_contents is called. */ 2614 if (!bfd_set_section_contents (output_bfd, output_section, "", 0, 1)) 2615 goto error_return; 2616 } 2617 new_contents = output_section->contents; 2618 BFD_ASSERT (new_contents != NULL); 2619 BFD_ASSERT (input_section->output_offset == 0); 2620 } 2621 else 2622 { 2623 /* Get and relocate the section contents. */ 2624 sec_size = (input_section->rawsize > input_section->size 2625 ? input_section->rawsize 2626 : input_section->size); 2627 contents = (bfd_byte *) bfd_malloc (sec_size); 2628 if (contents == NULL && sec_size != 0) 2629 goto error_return; 2630 new_contents = (bfd_get_relocated_section_contents 2631 (output_bfd, info, link_order, contents, 2632 bfd_link_relocatable (info), 2633 _bfd_generic_link_get_symbols (input_bfd))); 2634 if (!new_contents) 2635 goto error_return; 2636 } 2637 2638 /* Output the section contents. */ 2639 loc = input_section->output_offset * bfd_octets_per_byte (output_bfd); 2640 if (! bfd_set_section_contents (output_bfd, output_section, 2641 new_contents, loc, input_section->size)) 2642 goto error_return; 2643 2644 if (contents != NULL) 2645 free (contents); 2646 return TRUE; 2647 2648 error_return: 2649 if (contents != NULL) 2650 free (contents); 2651 return FALSE; 2652 } 2653 2654 /* A little routine to count the number of relocs in a link_order 2655 list. */ 2656 2657 unsigned int 2658 _bfd_count_link_order_relocs (struct bfd_link_order *link_order) 2659 { 2660 register unsigned int c; 2661 register struct bfd_link_order *l; 2662 2663 c = 0; 2664 for (l = link_order; l != NULL; l = l->next) 2665 { 2666 if (l->type == bfd_section_reloc_link_order 2667 || l->type == bfd_symbol_reloc_link_order) 2668 ++c; 2669 } 2670 2671 return c; 2672 } 2673 2674 /* 2675 FUNCTION 2676 bfd_link_split_section 2677 2678 SYNOPSIS 2679 bfd_boolean bfd_link_split_section (bfd *abfd, asection *sec); 2680 2681 DESCRIPTION 2682 Return nonzero if @var{sec} should be split during a 2683 reloceatable or final link. 2684 2685 .#define bfd_link_split_section(abfd, sec) \ 2686 . BFD_SEND (abfd, _bfd_link_split_section, (abfd, sec)) 2687 . 2688 2689 */ 2690 2691 bfd_boolean 2692 _bfd_generic_link_split_section (bfd *abfd ATTRIBUTE_UNUSED, 2693 asection *sec ATTRIBUTE_UNUSED) 2694 { 2695 return FALSE; 2696 } 2697 2698 /* 2699 FUNCTION 2700 bfd_section_already_linked 2701 2702 SYNOPSIS 2703 bfd_boolean bfd_section_already_linked (bfd *abfd, 2704 asection *sec, 2705 struct bfd_link_info *info); 2706 2707 DESCRIPTION 2708 Check if @var{data} has been already linked during a reloceatable 2709 or final link. Return TRUE if it has. 2710 2711 .#define bfd_section_already_linked(abfd, sec, info) \ 2712 . BFD_SEND (abfd, _section_already_linked, (abfd, sec, info)) 2713 . 2714 2715 */ 2716 2717 /* Sections marked with the SEC_LINK_ONCE flag should only be linked 2718 once into the output. This routine checks each section, and 2719 arrange to discard it if a section of the same name has already 2720 been linked. This code assumes that all relevant sections have the 2721 SEC_LINK_ONCE flag set; that is, it does not depend solely upon the 2722 section name. bfd_section_already_linked is called via 2723 bfd_map_over_sections. */ 2724 2725 /* The hash table. */ 2726 2727 static struct bfd_hash_table _bfd_section_already_linked_table; 2728 2729 /* Support routines for the hash table used by section_already_linked, 2730 initialize the table, traverse, lookup, fill in an entry and remove 2731 the table. */ 2732 2733 void 2734 bfd_section_already_linked_table_traverse 2735 (bfd_boolean (*func) (struct bfd_section_already_linked_hash_entry *, 2736 void *), void *info) 2737 { 2738 bfd_hash_traverse (&_bfd_section_already_linked_table, 2739 (bfd_boolean (*) (struct bfd_hash_entry *, 2740 void *)) func, 2741 info); 2742 } 2743 2744 struct bfd_section_already_linked_hash_entry * 2745 bfd_section_already_linked_table_lookup (const char *name) 2746 { 2747 return ((struct bfd_section_already_linked_hash_entry *) 2748 bfd_hash_lookup (&_bfd_section_already_linked_table, name, 2749 TRUE, FALSE)); 2750 } 2751 2752 bfd_boolean 2753 bfd_section_already_linked_table_insert 2754 (struct bfd_section_already_linked_hash_entry *already_linked_list, 2755 asection *sec) 2756 { 2757 struct bfd_section_already_linked *l; 2758 2759 /* Allocate the memory from the same obstack as the hash table is 2760 kept in. */ 2761 l = (struct bfd_section_already_linked *) 2762 bfd_hash_allocate (&_bfd_section_already_linked_table, sizeof *l); 2763 if (l == NULL) 2764 return FALSE; 2765 l->sec = sec; 2766 l->next = already_linked_list->entry; 2767 already_linked_list->entry = l; 2768 return TRUE; 2769 } 2770 2771 static struct bfd_hash_entry * 2772 already_linked_newfunc (struct bfd_hash_entry *entry ATTRIBUTE_UNUSED, 2773 struct bfd_hash_table *table, 2774 const char *string ATTRIBUTE_UNUSED) 2775 { 2776 struct bfd_section_already_linked_hash_entry *ret = 2777 (struct bfd_section_already_linked_hash_entry *) 2778 bfd_hash_allocate (table, sizeof *ret); 2779 2780 if (ret == NULL) 2781 return NULL; 2782 2783 ret->entry = NULL; 2784 2785 return &ret->root; 2786 } 2787 2788 bfd_boolean 2789 bfd_section_already_linked_table_init (void) 2790 { 2791 return bfd_hash_table_init_n (&_bfd_section_already_linked_table, 2792 already_linked_newfunc, 2793 sizeof (struct bfd_section_already_linked_hash_entry), 2794 42); 2795 } 2796 2797 void 2798 bfd_section_already_linked_table_free (void) 2799 { 2800 bfd_hash_table_free (&_bfd_section_already_linked_table); 2801 } 2802 2803 /* Report warnings as appropriate for duplicate section SEC. 2804 Return FALSE if we decide to keep SEC after all. */ 2805 2806 bfd_boolean 2807 _bfd_handle_already_linked (asection *sec, 2808 struct bfd_section_already_linked *l, 2809 struct bfd_link_info *info) 2810 { 2811 switch (sec->flags & SEC_LINK_DUPLICATES) 2812 { 2813 default: 2814 abort (); 2815 2816 case SEC_LINK_DUPLICATES_DISCARD: 2817 /* If we found an LTO IR match for this comdat group on 2818 the first pass, replace it with the LTO output on the 2819 second pass. We can't simply choose real object 2820 files over IR because the first pass may contain a 2821 mix of LTO and normal objects and we must keep the 2822 first match, be it IR or real. */ 2823 if (sec->owner->lto_output 2824 && (l->sec->owner->flags & BFD_PLUGIN) != 0) 2825 { 2826 l->sec = sec; 2827 return FALSE; 2828 } 2829 break; 2830 2831 case SEC_LINK_DUPLICATES_ONE_ONLY: 2832 info->callbacks->einfo 2833 /* xgettext:c-format */ 2834 (_("%B: ignoring duplicate section `%A'\n"), 2835 sec->owner, sec); 2836 break; 2837 2838 case SEC_LINK_DUPLICATES_SAME_SIZE: 2839 if ((l->sec->owner->flags & BFD_PLUGIN) != 0) 2840 ; 2841 else if (sec->size != l->sec->size) 2842 info->callbacks->einfo 2843 /* xgettext:c-format */ 2844 (_("%B: duplicate section `%A' has different size\n"), 2845 sec->owner, sec); 2846 break; 2847 2848 case SEC_LINK_DUPLICATES_SAME_CONTENTS: 2849 if ((l->sec->owner->flags & BFD_PLUGIN) != 0) 2850 ; 2851 else if (sec->size != l->sec->size) 2852 info->callbacks->einfo 2853 /* xgettext:c-format */ 2854 (_("%B: duplicate section `%A' has different size\n"), 2855 sec->owner, sec); 2856 else if (sec->size != 0) 2857 { 2858 bfd_byte *sec_contents, *l_sec_contents = NULL; 2859 2860 if (!bfd_malloc_and_get_section (sec->owner, sec, &sec_contents)) 2861 info->callbacks->einfo 2862 /* xgettext:c-format */ 2863 (_("%B: could not read contents of section `%A'\n"), 2864 sec->owner, sec); 2865 else if (!bfd_malloc_and_get_section (l->sec->owner, l->sec, 2866 &l_sec_contents)) 2867 info->callbacks->einfo 2868 /* xgettext:c-format */ 2869 (_("%B: could not read contents of section `%A'\n"), 2870 l->sec->owner, l->sec); 2871 else if (memcmp (sec_contents, l_sec_contents, sec->size) != 0) 2872 info->callbacks->einfo 2873 /* xgettext:c-format */ 2874 (_("%B: duplicate section `%A' has different contents\n"), 2875 sec->owner, sec); 2876 2877 if (sec_contents) 2878 free (sec_contents); 2879 if (l_sec_contents) 2880 free (l_sec_contents); 2881 } 2882 break; 2883 } 2884 2885 /* Set the output_section field so that lang_add_section 2886 does not create a lang_input_section structure for this 2887 section. Since there might be a symbol in the section 2888 being discarded, we must retain a pointer to the section 2889 which we are really going to use. */ 2890 sec->output_section = bfd_abs_section_ptr; 2891 sec->kept_section = l->sec; 2892 return TRUE; 2893 } 2894 2895 /* This is used on non-ELF inputs. */ 2896 2897 bfd_boolean 2898 _bfd_generic_section_already_linked (bfd *abfd ATTRIBUTE_UNUSED, 2899 asection *sec, 2900 struct bfd_link_info *info) 2901 { 2902 const char *name; 2903 struct bfd_section_already_linked *l; 2904 struct bfd_section_already_linked_hash_entry *already_linked_list; 2905 2906 if ((sec->flags & SEC_LINK_ONCE) == 0) 2907 return FALSE; 2908 2909 /* The generic linker doesn't handle section groups. */ 2910 if ((sec->flags & SEC_GROUP) != 0) 2911 return FALSE; 2912 2913 /* FIXME: When doing a relocatable link, we may have trouble 2914 copying relocations in other sections that refer to local symbols 2915 in the section being discarded. Those relocations will have to 2916 be converted somehow; as of this writing I'm not sure that any of 2917 the backends handle that correctly. 2918 2919 It is tempting to instead not discard link once sections when 2920 doing a relocatable link (technically, they should be discarded 2921 whenever we are building constructors). However, that fails, 2922 because the linker winds up combining all the link once sections 2923 into a single large link once section, which defeats the purpose 2924 of having link once sections in the first place. */ 2925 2926 name = bfd_get_section_name (abfd, sec); 2927 2928 already_linked_list = bfd_section_already_linked_table_lookup (name); 2929 2930 l = already_linked_list->entry; 2931 if (l != NULL) 2932 { 2933 /* The section has already been linked. See if we should 2934 issue a warning. */ 2935 return _bfd_handle_already_linked (sec, l, info); 2936 } 2937 2938 /* This is the first section with this name. Record it. */ 2939 if (!bfd_section_already_linked_table_insert (already_linked_list, sec)) 2940 info->callbacks->einfo (_("%F%P: already_linked_table: %E\n")); 2941 return FALSE; 2942 } 2943 2944 /* Choose a neighbouring section to S in OBFD that will be output, or 2945 the absolute section if ADDR is out of bounds of the neighbours. */ 2946 2947 asection * 2948 _bfd_nearby_section (bfd *obfd, asection *s, bfd_vma addr) 2949 { 2950 asection *next, *prev, *best; 2951 2952 /* Find preceding kept section. */ 2953 for (prev = s->prev; prev != NULL; prev = prev->prev) 2954 if ((prev->flags & SEC_EXCLUDE) == 0 2955 && !bfd_section_removed_from_list (obfd, prev)) 2956 break; 2957 2958 /* Find following kept section. Start at prev->next because 2959 other sections may have been added after S was removed. */ 2960 if (s->prev != NULL) 2961 next = s->prev->next; 2962 else 2963 next = s->owner->sections; 2964 for (; next != NULL; next = next->next) 2965 if ((next->flags & SEC_EXCLUDE) == 0 2966 && !bfd_section_removed_from_list (obfd, next)) 2967 break; 2968 2969 /* Choose better of two sections, based on flags. The idea 2970 is to choose a section that will be in the same segment 2971 as S would have been if it was kept. */ 2972 best = next; 2973 if (prev == NULL) 2974 { 2975 if (next == NULL) 2976 best = bfd_abs_section_ptr; 2977 } 2978 else if (next == NULL) 2979 best = prev; 2980 else if (((prev->flags ^ next->flags) 2981 & (SEC_ALLOC | SEC_THREAD_LOCAL | SEC_LOAD)) != 0) 2982 { 2983 if (((next->flags ^ s->flags) 2984 & (SEC_ALLOC | SEC_THREAD_LOCAL)) != 0 2985 /* We prefer to choose a loaded section. Section S 2986 doesn't have SEC_LOAD set (it being excluded, that 2987 part of the flag processing didn't happen) so we 2988 can't compare that flag to those of NEXT and PREV. */ 2989 || ((prev->flags & SEC_LOAD) != 0 2990 && (next->flags & SEC_LOAD) == 0)) 2991 best = prev; 2992 } 2993 else if (((prev->flags ^ next->flags) & SEC_READONLY) != 0) 2994 { 2995 if (((next->flags ^ s->flags) & SEC_READONLY) != 0) 2996 best = prev; 2997 } 2998 else if (((prev->flags ^ next->flags) & SEC_CODE) != 0) 2999 { 3000 if (((next->flags ^ s->flags) & SEC_CODE) != 0) 3001 best = prev; 3002 } 3003 else 3004 { 3005 /* Flags we care about are the same. Prefer the following 3006 section if that will result in a positive valued sym. */ 3007 if (addr < next->vma) 3008 best = prev; 3009 } 3010 3011 return best; 3012 } 3013 3014 /* Convert symbols in excluded output sections to use a kept section. */ 3015 3016 static bfd_boolean 3017 fix_syms (struct bfd_link_hash_entry *h, void *data) 3018 { 3019 bfd *obfd = (bfd *) data; 3020 3021 if (h->type == bfd_link_hash_defined 3022 || h->type == bfd_link_hash_defweak) 3023 { 3024 asection *s = h->u.def.section; 3025 if (s != NULL 3026 && s->output_section != NULL 3027 && (s->output_section->flags & SEC_EXCLUDE) != 0 3028 && bfd_section_removed_from_list (obfd, s->output_section)) 3029 { 3030 asection *op; 3031 3032 h->u.def.value += s->output_offset + s->output_section->vma; 3033 op = _bfd_nearby_section (obfd, s->output_section, h->u.def.value); 3034 h->u.def.value -= op->vma; 3035 h->u.def.section = op; 3036 } 3037 } 3038 3039 return TRUE; 3040 } 3041 3042 void 3043 _bfd_fix_excluded_sec_syms (bfd *obfd, struct bfd_link_info *info) 3044 { 3045 bfd_link_hash_traverse (info->hash, fix_syms, obfd); 3046 } 3047 3048 /* 3049 FUNCTION 3050 bfd_generic_define_common_symbol 3051 3052 SYNOPSIS 3053 bfd_boolean bfd_generic_define_common_symbol 3054 (bfd *output_bfd, struct bfd_link_info *info, 3055 struct bfd_link_hash_entry *h); 3056 3057 DESCRIPTION 3058 Convert common symbol @var{h} into a defined symbol. 3059 Return TRUE on success and FALSE on failure. 3060 3061 .#define bfd_define_common_symbol(output_bfd, info, h) \ 3062 . BFD_SEND (output_bfd, _bfd_define_common_symbol, (output_bfd, info, h)) 3063 . 3064 */ 3065 3066 bfd_boolean 3067 bfd_generic_define_common_symbol (bfd *output_bfd, 3068 struct bfd_link_info *info ATTRIBUTE_UNUSED, 3069 struct bfd_link_hash_entry *h) 3070 { 3071 unsigned int power_of_two; 3072 bfd_vma alignment, size; 3073 asection *section; 3074 3075 BFD_ASSERT (h != NULL && h->type == bfd_link_hash_common); 3076 3077 size = h->u.c.size; 3078 power_of_two = h->u.c.p->alignment_power; 3079 section = h->u.c.p->section; 3080 3081 /* Increase the size of the section to align the common symbol. 3082 The alignment must be a power of two. */ 3083 alignment = bfd_octets_per_byte (output_bfd) << power_of_two; 3084 BFD_ASSERT (alignment != 0 && (alignment & -alignment) == alignment); 3085 section->size += alignment - 1; 3086 section->size &= -alignment; 3087 3088 /* Adjust the section's overall alignment if necessary. */ 3089 if (power_of_two > section->alignment_power) 3090 section->alignment_power = power_of_two; 3091 3092 /* Change the symbol from common to defined. */ 3093 h->type = bfd_link_hash_defined; 3094 h->u.def.section = section; 3095 h->u.def.value = section->size; 3096 3097 /* Increase the size of the section. */ 3098 section->size += size; 3099 3100 /* Make sure the section is allocated in memory, and make sure that 3101 it is no longer a common section. */ 3102 section->flags |= SEC_ALLOC; 3103 section->flags &= ~SEC_IS_COMMON; 3104 return TRUE; 3105 } 3106 3107 /* 3108 FUNCTION 3109 bfd_generic_define_start_stop 3110 3111 SYNOPSIS 3112 struct bfd_link_hash_entry *bfd_generic_define_start_stop 3113 (struct bfd_link_info *info, 3114 const char *symbol, asection *sec); 3115 3116 DESCRIPTION 3117 Define a __start, __stop, .startof. or .sizeof. symbol. 3118 Return the symbol or NULL if no such undefined symbol exists. 3119 3120 .#define bfd_define_start_stop(output_bfd, info, symbol, sec) \ 3121 . BFD_SEND (output_bfd, _bfd_define_start_stop, (info, symbol, sec)) 3122 . 3123 */ 3124 3125 struct bfd_link_hash_entry * 3126 bfd_generic_define_start_stop (struct bfd_link_info *info, 3127 const char *symbol, asection *sec) 3128 { 3129 struct bfd_link_hash_entry *h; 3130 3131 h = bfd_link_hash_lookup (info->hash, symbol, FALSE, FALSE, TRUE); 3132 if (h != NULL 3133 && (h->type == bfd_link_hash_undefined 3134 || h->type == bfd_link_hash_undefweak)) 3135 { 3136 h->type = bfd_link_hash_defined; 3137 h->u.def.section = sec; 3138 h->u.def.value = 0; 3139 return h; 3140 } 3141 return NULL; 3142 } 3143 3144 /* 3145 FUNCTION 3146 bfd_find_version_for_sym 3147 3148 SYNOPSIS 3149 struct bfd_elf_version_tree * bfd_find_version_for_sym 3150 (struct bfd_elf_version_tree *verdefs, 3151 const char *sym_name, bfd_boolean *hide); 3152 3153 DESCRIPTION 3154 Search an elf version script tree for symbol versioning 3155 info and export / don't-export status for a given symbol. 3156 Return non-NULL on success and NULL on failure; also sets 3157 the output @samp{hide} boolean parameter. 3158 3159 */ 3160 3161 struct bfd_elf_version_tree * 3162 bfd_find_version_for_sym (struct bfd_elf_version_tree *verdefs, 3163 const char *sym_name, 3164 bfd_boolean *hide) 3165 { 3166 struct bfd_elf_version_tree *t; 3167 struct bfd_elf_version_tree *local_ver, *global_ver, *exist_ver; 3168 struct bfd_elf_version_tree *star_local_ver, *star_global_ver; 3169 3170 local_ver = NULL; 3171 global_ver = NULL; 3172 star_local_ver = NULL; 3173 star_global_ver = NULL; 3174 exist_ver = NULL; 3175 for (t = verdefs; t != NULL; t = t->next) 3176 { 3177 if (t->globals.list != NULL) 3178 { 3179 struct bfd_elf_version_expr *d = NULL; 3180 3181 while ((d = (*t->match) (&t->globals, d, sym_name)) != NULL) 3182 { 3183 if (d->literal || strcmp (d->pattern, "*") != 0) 3184 global_ver = t; 3185 else 3186 star_global_ver = t; 3187 if (d->symver) 3188 exist_ver = t; 3189 d->script = 1; 3190 /* If the match is a wildcard pattern, keep looking for 3191 a more explicit, perhaps even local, match. */ 3192 if (d->literal) 3193 break; 3194 } 3195 3196 if (d != NULL) 3197 break; 3198 } 3199 3200 if (t->locals.list != NULL) 3201 { 3202 struct bfd_elf_version_expr *d = NULL; 3203 3204 while ((d = (*t->match) (&t->locals, d, sym_name)) != NULL) 3205 { 3206 if (d->literal || strcmp (d->pattern, "*") != 0) 3207 local_ver = t; 3208 else 3209 star_local_ver = t; 3210 /* If the match is a wildcard pattern, keep looking for 3211 a more explicit, perhaps even global, match. */ 3212 if (d->literal) 3213 { 3214 /* An exact match overrides a global wildcard. */ 3215 global_ver = NULL; 3216 star_global_ver = NULL; 3217 break; 3218 } 3219 } 3220 3221 if (d != NULL) 3222 break; 3223 } 3224 } 3225 3226 if (global_ver == NULL && local_ver == NULL) 3227 global_ver = star_global_ver; 3228 3229 if (global_ver != NULL) 3230 { 3231 /* If we already have a versioned symbol that matches the 3232 node for this symbol, then we don't want to create a 3233 duplicate from the unversioned symbol. Instead hide the 3234 unversioned symbol. */ 3235 *hide = exist_ver == global_ver; 3236 return global_ver; 3237 } 3238 3239 if (local_ver == NULL) 3240 local_ver = star_local_ver; 3241 3242 if (local_ver != NULL) 3243 { 3244 *hide = TRUE; 3245 return local_ver; 3246 } 3247 3248 return NULL; 3249 } 3250 3251 /* 3252 FUNCTION 3253 bfd_hide_sym_by_version 3254 3255 SYNOPSIS 3256 bfd_boolean bfd_hide_sym_by_version 3257 (struct bfd_elf_version_tree *verdefs, const char *sym_name); 3258 3259 DESCRIPTION 3260 Search an elf version script tree for symbol versioning 3261 info for a given symbol. Return TRUE if the symbol is hidden. 3262 3263 */ 3264 3265 bfd_boolean 3266 bfd_hide_sym_by_version (struct bfd_elf_version_tree *verdefs, 3267 const char *sym_name) 3268 { 3269 bfd_boolean hidden = FALSE; 3270 bfd_find_version_for_sym (verdefs, sym_name, &hidden); 3271 return hidden; 3272 } 3273 3274 /* 3275 FUNCTION 3276 bfd_link_check_relocs 3277 3278 SYNOPSIS 3279 bfd_boolean bfd_link_check_relocs 3280 (bfd *abfd, struct bfd_link_info *info); 3281 3282 DESCRIPTION 3283 Checks the relocs in ABFD for validity. 3284 Does not execute the relocs. 3285 Return TRUE if everything is OK, FALSE otherwise. 3286 This is the external entry point to this code. 3287 */ 3288 3289 bfd_boolean 3290 bfd_link_check_relocs (bfd *abfd, struct bfd_link_info *info) 3291 { 3292 return BFD_SEND (abfd, _bfd_link_check_relocs, (abfd, info)); 3293 } 3294 3295 /* 3296 FUNCTION 3297 _bfd_generic_link_check_relocs 3298 3299 SYNOPSIS 3300 bfd_boolean _bfd_generic_link_check_relocs 3301 (bfd *abfd, struct bfd_link_info *info); 3302 3303 DESCRIPTION 3304 Stub function for targets that do not implement reloc checking. 3305 Return TRUE. 3306 This is an internal function. It should not be called from 3307 outside the BFD library. 3308 */ 3309 3310 bfd_boolean 3311 _bfd_generic_link_check_relocs (bfd *abfd ATTRIBUTE_UNUSED, 3312 struct bfd_link_info *info ATTRIBUTE_UNUSED) 3313 { 3314 return TRUE; 3315 } 3316 3317 /* 3318 FUNCTION 3319 bfd_merge_private_bfd_data 3320 3321 SYNOPSIS 3322 bfd_boolean bfd_merge_private_bfd_data 3323 (bfd *ibfd, struct bfd_link_info *info); 3324 3325 DESCRIPTION 3326 Merge private BFD information from the BFD @var{ibfd} to the 3327 the output file BFD when linking. Return <<TRUE>> on success, 3328 <<FALSE>> on error. Possible error returns are: 3329 3330 o <<bfd_error_no_memory>> - 3331 Not enough memory exists to create private data for @var{obfd}. 3332 3333 .#define bfd_merge_private_bfd_data(ibfd, info) \ 3334 . BFD_SEND ((info)->output_bfd, _bfd_merge_private_bfd_data, \ 3335 . (ibfd, info)) 3336 */ 3337 3338 /* 3339 INTERNAL_FUNCTION 3340 _bfd_generic_verify_endian_match 3341 3342 SYNOPSIS 3343 bfd_boolean _bfd_generic_verify_endian_match 3344 (bfd *ibfd, struct bfd_link_info *info); 3345 3346 DESCRIPTION 3347 Can be used from / for bfd_merge_private_bfd_data to check that 3348 endianness matches between input and output file. Returns 3349 TRUE for a match, otherwise returns FALSE and emits an error. 3350 */ 3351 3352 bfd_boolean 3353 _bfd_generic_verify_endian_match (bfd *ibfd, struct bfd_link_info *info) 3354 { 3355 bfd *obfd = info->output_bfd; 3356 3357 if (ibfd->xvec->byteorder != obfd->xvec->byteorder 3358 && ibfd->xvec->byteorder != BFD_ENDIAN_UNKNOWN 3359 && obfd->xvec->byteorder != BFD_ENDIAN_UNKNOWN) 3360 { 3361 if (bfd_big_endian (ibfd)) 3362 _bfd_error_handler (_("%B: compiled for a big endian system " 3363 "and target is little endian"), ibfd); 3364 else 3365 _bfd_error_handler (_("%B: compiled for a little endian system " 3366 "and target is big endian"), ibfd); 3367 bfd_set_error (bfd_error_wrong_format); 3368 return FALSE; 3369 } 3370 3371 return TRUE; 3372 } 3373