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