1 /* linker.c -- BFD linker routines 2 Copyright (C) 1993-2014 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 (strcmp (name, "__gnu_lto_slim") == 0) 1484 (*_bfd_error_handler) 1485 (_("%s: plugin needed to handle lto object"), 1486 bfd_get_filename (abfd)); 1487 } 1488 else 1489 row = DEF_ROW; 1490 1491 if (hashp != NULL && *hashp != NULL) 1492 h = *hashp; 1493 else 1494 { 1495 if (row == UNDEF_ROW || row == UNDEFW_ROW) 1496 h = bfd_wrapped_link_hash_lookup (abfd, info, name, TRUE, copy, FALSE); 1497 else 1498 h = bfd_link_hash_lookup (info->hash, name, TRUE, copy, FALSE); 1499 if (h == NULL) 1500 { 1501 if (hashp != NULL) 1502 *hashp = NULL; 1503 return FALSE; 1504 } 1505 } 1506 1507 if (info->notice_all 1508 || (info->notice_hash != NULL 1509 && bfd_hash_lookup (info->notice_hash, name, FALSE, FALSE) != NULL)) 1510 { 1511 if (! (*info->callbacks->notice) (info, h, inh, 1512 abfd, section, value, flags)) 1513 return FALSE; 1514 } 1515 1516 if (hashp != NULL) 1517 *hashp = h; 1518 1519 do 1520 { 1521 enum link_action action; 1522 1523 cycle = FALSE; 1524 action = link_action[(int) row][(int) h->type]; 1525 switch (action) 1526 { 1527 case FAIL: 1528 abort (); 1529 1530 case NOACT: 1531 /* Do nothing. */ 1532 break; 1533 1534 case UND: 1535 /* Make a new undefined symbol. */ 1536 h->type = bfd_link_hash_undefined; 1537 h->u.undef.abfd = abfd; 1538 bfd_link_add_undef (info->hash, h); 1539 break; 1540 1541 case WEAK: 1542 /* Make a new weak undefined symbol. */ 1543 h->type = bfd_link_hash_undefweak; 1544 h->u.undef.abfd = abfd; 1545 break; 1546 1547 case CDEF: 1548 /* We have found a definition for a symbol which was 1549 previously common. */ 1550 BFD_ASSERT (h->type == bfd_link_hash_common); 1551 if (! ((*info->callbacks->multiple_common) 1552 (info, h, abfd, bfd_link_hash_defined, 0))) 1553 return FALSE; 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 1569 /* If we have been asked to, we act like collect2 and 1570 identify all functions that might be global 1571 constructors and destructors and pass them up in a 1572 callback. We only do this for certain object file 1573 types, since many object file types can handle this 1574 automatically. */ 1575 if (collect && name[0] == '_') 1576 { 1577 const char *s; 1578 1579 /* A constructor or destructor name starts like this: 1580 _+GLOBAL_[_.$][ID][_.$] where the first [_.$] and 1581 the second are the same character (we accept any 1582 character there, in case a new object file format 1583 comes along with even worse naming restrictions). */ 1584 1585 #define CONS_PREFIX "GLOBAL_" 1586 #define CONS_PREFIX_LEN (sizeof CONS_PREFIX - 1) 1587 1588 s = name + 1; 1589 while (*s == '_') 1590 ++s; 1591 if (s[0] == 'G' && CONST_STRNEQ (s, CONS_PREFIX)) 1592 { 1593 char c; 1594 1595 c = s[CONS_PREFIX_LEN + 1]; 1596 if ((c == 'I' || c == 'D') 1597 && s[CONS_PREFIX_LEN] == s[CONS_PREFIX_LEN + 2]) 1598 { 1599 /* If this is a definition of a symbol which 1600 was previously weakly defined, we are in 1601 trouble. We have already added a 1602 constructor entry for the weak defined 1603 symbol, and now we are trying to add one 1604 for the new symbol. Fortunately, this case 1605 should never arise in practice. */ 1606 if (oldtype == bfd_link_hash_defweak) 1607 abort (); 1608 1609 if (! ((*info->callbacks->constructor) 1610 (info, c == 'I', 1611 h->root.string, abfd, section, value))) 1612 return FALSE; 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 break; 1668 1669 case REF: 1670 /* A reference to a defined symbol. */ 1671 if (h->u.undef.next == NULL && info->hash->undefs_tail != h) 1672 h->u.undef.next = h; 1673 break; 1674 1675 case BIG: 1676 /* We have found a common definition for a symbol which 1677 already had a common definition. Use the maximum of the 1678 two sizes, and use the section required by the larger symbol. */ 1679 BFD_ASSERT (h->type == bfd_link_hash_common); 1680 if (! ((*info->callbacks->multiple_common) 1681 (info, h, abfd, bfd_link_hash_common, value))) 1682 return FALSE; 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 if (! ((*info->callbacks->multiple_common) 1721 (info, h, abfd, bfd_link_hash_common, value))) 1722 return FALSE; 1723 break; 1724 1725 case MIND: 1726 /* Multiple indirect symbols. This is OK if they both point 1727 to the same symbol. */ 1728 if (strcmp (h->u.i.link->root.string, string) == 0) 1729 break; 1730 /* Fall through. */ 1731 case MDEF: 1732 /* Handle a multiple definition. */ 1733 if (! ((*info->callbacks->multiple_definition) 1734 (info, h, abfd, section, value))) 1735 return FALSE; 1736 break; 1737 1738 case CIND: 1739 /* Create an indirect symbol from an existing common symbol. */ 1740 BFD_ASSERT (h->type == bfd_link_hash_common); 1741 if (! ((*info->callbacks->multiple_common) 1742 (info, h, abfd, bfd_link_hash_indirect, 0))) 1743 return FALSE; 1744 /* Fall through. */ 1745 case IND: 1746 if (inh->type == bfd_link_hash_indirect 1747 && inh->u.i.link == h) 1748 { 1749 (*_bfd_error_handler) 1750 (_("%B: indirect symbol `%s' to `%s' is a loop"), 1751 abfd, name, string); 1752 bfd_set_error (bfd_error_invalid_operation); 1753 return FALSE; 1754 } 1755 if (inh->type == bfd_link_hash_new) 1756 { 1757 inh->type = bfd_link_hash_undefined; 1758 inh->u.undef.abfd = abfd; 1759 bfd_link_add_undef (info->hash, inh); 1760 } 1761 1762 /* If the indirect symbol has been referenced, we need to 1763 push the reference down to the symbol we are referencing. */ 1764 if (h->type != bfd_link_hash_new) 1765 { 1766 /* ??? If inh->type == bfd_link_hash_undefweak this 1767 converts inh to bfd_link_hash_undefined. */ 1768 row = UNDEF_ROW; 1769 cycle = TRUE; 1770 } 1771 1772 h->type = bfd_link_hash_indirect; 1773 h->u.i.link = inh; 1774 /* Not setting h = h->u.i.link here means that when cycle is 1775 set above we'll always go to REFC, and then cycle again 1776 to the indirected symbol. This means that any successful 1777 change of an existing symbol to indirect counts as a 1778 reference. ??? That may not be correct when the existing 1779 symbol was defweak. */ 1780 break; 1781 1782 case SET: 1783 /* Add an entry to a set. */ 1784 if (! (*info->callbacks->add_to_set) (info, h, BFD_RELOC_CTOR, 1785 abfd, section, value)) 1786 return FALSE; 1787 break; 1788 1789 case WARNC: 1790 /* Issue a warning and cycle, except when the reference is 1791 in LTO IR. */ 1792 if (h->u.i.warning != NULL 1793 && (abfd->flags & BFD_PLUGIN) == 0) 1794 { 1795 if (! (*info->callbacks->warning) (info, h->u.i.warning, 1796 h->root.string, abfd, 1797 NULL, 0)) 1798 return FALSE; 1799 /* Only issue a warning once. */ 1800 h->u.i.warning = NULL; 1801 } 1802 /* Fall through. */ 1803 case CYCLE: 1804 /* Try again with the referenced symbol. */ 1805 h = h->u.i.link; 1806 cycle = TRUE; 1807 break; 1808 1809 case REFC: 1810 /* A reference to an indirect symbol. */ 1811 if (h->u.undef.next == NULL && info->hash->undefs_tail != h) 1812 h->u.undef.next = h; 1813 h = h->u.i.link; 1814 cycle = TRUE; 1815 break; 1816 1817 case WARN: 1818 /* Warn if this symbol has been referenced already from non-IR, 1819 otherwise add a warning. */ 1820 if ((!info->lto_plugin_active 1821 && (h->u.undef.next != NULL || info->hash->undefs_tail == h)) 1822 || h->non_ir_ref) 1823 { 1824 if (! (*info->callbacks->warning) (info, string, h->root.string, 1825 hash_entry_bfd (h), NULL, 0)) 1826 return FALSE; 1827 break; 1828 } 1829 /* Fall through. */ 1830 case MWARN: 1831 /* Make a warning symbol. */ 1832 { 1833 struct bfd_link_hash_entry *sub; 1834 1835 /* STRING is the warning to give. */ 1836 sub = ((struct bfd_link_hash_entry *) 1837 ((*info->hash->table.newfunc) 1838 (NULL, &info->hash->table, h->root.string))); 1839 if (sub == NULL) 1840 return FALSE; 1841 *sub = *h; 1842 sub->type = bfd_link_hash_warning; 1843 sub->u.i.link = h; 1844 if (! copy) 1845 sub->u.i.warning = string; 1846 else 1847 { 1848 char *w; 1849 size_t len = strlen (string) + 1; 1850 1851 w = (char *) bfd_hash_allocate (&info->hash->table, len); 1852 if (w == NULL) 1853 return FALSE; 1854 memcpy (w, string, len); 1855 sub->u.i.warning = w; 1856 } 1857 1858 bfd_hash_replace (&info->hash->table, 1859 (struct bfd_hash_entry *) h, 1860 (struct bfd_hash_entry *) sub); 1861 if (hashp != NULL) 1862 *hashp = sub; 1863 } 1864 break; 1865 } 1866 } 1867 while (cycle); 1868 1869 return TRUE; 1870 } 1871 1872 /* Generic final link routine. */ 1874 1875 bfd_boolean 1876 _bfd_generic_final_link (bfd *abfd, struct bfd_link_info *info) 1877 { 1878 bfd *sub; 1879 asection *o; 1880 struct bfd_link_order *p; 1881 size_t outsymalloc; 1882 struct generic_write_global_symbol_info wginfo; 1883 1884 bfd_get_outsymbols (abfd) = NULL; 1885 bfd_get_symcount (abfd) = 0; 1886 outsymalloc = 0; 1887 1888 /* Mark all sections which will be included in the output file. */ 1889 for (o = abfd->sections; o != NULL; o = o->next) 1890 for (p = o->map_head.link_order; p != NULL; p = p->next) 1891 if (p->type == bfd_indirect_link_order) 1892 p->u.indirect.section->linker_mark = TRUE; 1893 1894 /* Build the output symbol table. */ 1895 for (sub = info->input_bfds; sub != NULL; sub = sub->link.next) 1896 if (! _bfd_generic_link_output_symbols (abfd, sub, info, &outsymalloc)) 1897 return FALSE; 1898 1899 /* Accumulate the global symbols. */ 1900 wginfo.info = info; 1901 wginfo.output_bfd = abfd; 1902 wginfo.psymalloc = &outsymalloc; 1903 _bfd_generic_link_hash_traverse (_bfd_generic_hash_table (info), 1904 _bfd_generic_link_write_global_symbol, 1905 &wginfo); 1906 1907 /* Make sure we have a trailing NULL pointer on OUTSYMBOLS. We 1908 shouldn't really need one, since we have SYMCOUNT, but some old 1909 code still expects one. */ 1910 if (! generic_add_output_symbol (abfd, &outsymalloc, NULL)) 1911 return FALSE; 1912 1913 if (info->relocatable) 1914 { 1915 /* Allocate space for the output relocs for each section. */ 1916 for (o = abfd->sections; o != NULL; o = o->next) 1917 { 1918 o->reloc_count = 0; 1919 for (p = o->map_head.link_order; p != NULL; p = p->next) 1920 { 1921 if (p->type == bfd_section_reloc_link_order 1922 || p->type == bfd_symbol_reloc_link_order) 1923 ++o->reloc_count; 1924 else if (p->type == bfd_indirect_link_order) 1925 { 1926 asection *input_section; 1927 bfd *input_bfd; 1928 long relsize; 1929 arelent **relocs; 1930 asymbol **symbols; 1931 long reloc_count; 1932 1933 input_section = p->u.indirect.section; 1934 input_bfd = input_section->owner; 1935 relsize = bfd_get_reloc_upper_bound (input_bfd, 1936 input_section); 1937 if (relsize < 0) 1938 return FALSE; 1939 relocs = (arelent **) bfd_malloc (relsize); 1940 if (!relocs && relsize != 0) 1941 return FALSE; 1942 symbols = _bfd_generic_link_get_symbols (input_bfd); 1943 reloc_count = bfd_canonicalize_reloc (input_bfd, 1944 input_section, 1945 relocs, 1946 symbols); 1947 free (relocs); 1948 if (reloc_count < 0) 1949 return FALSE; 1950 BFD_ASSERT ((unsigned long) reloc_count 1951 == input_section->reloc_count); 1952 o->reloc_count += reloc_count; 1953 } 1954 } 1955 if (o->reloc_count > 0) 1956 { 1957 bfd_size_type amt; 1958 1959 amt = o->reloc_count; 1960 amt *= sizeof (arelent *); 1961 o->orelocation = (struct reloc_cache_entry **) bfd_alloc (abfd, amt); 1962 if (!o->orelocation) 1963 return FALSE; 1964 o->flags |= SEC_RELOC; 1965 /* Reset the count so that it can be used as an index 1966 when putting in the output relocs. */ 1967 o->reloc_count = 0; 1968 } 1969 } 1970 } 1971 1972 /* Handle all the link order information for the sections. */ 1973 for (o = abfd->sections; o != NULL; o = o->next) 1974 { 1975 for (p = o->map_head.link_order; p != NULL; p = p->next) 1976 { 1977 switch (p->type) 1978 { 1979 case bfd_section_reloc_link_order: 1980 case bfd_symbol_reloc_link_order: 1981 if (! _bfd_generic_reloc_link_order (abfd, info, o, p)) 1982 return FALSE; 1983 break; 1984 case bfd_indirect_link_order: 1985 if (! default_indirect_link_order (abfd, info, o, p, TRUE)) 1986 return FALSE; 1987 break; 1988 default: 1989 if (! _bfd_default_link_order (abfd, info, o, p)) 1990 return FALSE; 1991 break; 1992 } 1993 } 1994 } 1995 1996 return TRUE; 1997 } 1998 1999 /* Add an output symbol to the output BFD. */ 2000 2001 static bfd_boolean 2002 generic_add_output_symbol (bfd *output_bfd, size_t *psymalloc, asymbol *sym) 2003 { 2004 if (bfd_get_symcount (output_bfd) >= *psymalloc) 2005 { 2006 asymbol **newsyms; 2007 bfd_size_type amt; 2008 2009 if (*psymalloc == 0) 2010 *psymalloc = 124; 2011 else 2012 *psymalloc *= 2; 2013 amt = *psymalloc; 2014 amt *= sizeof (asymbol *); 2015 newsyms = (asymbol **) bfd_realloc (bfd_get_outsymbols (output_bfd), amt); 2016 if (newsyms == NULL) 2017 return FALSE; 2018 bfd_get_outsymbols (output_bfd) = newsyms; 2019 } 2020 2021 bfd_get_outsymbols (output_bfd) [bfd_get_symcount (output_bfd)] = sym; 2022 if (sym != NULL) 2023 ++ bfd_get_symcount (output_bfd); 2024 2025 return TRUE; 2026 } 2027 2028 /* Handle the symbols for an input BFD. */ 2029 2030 bfd_boolean 2031 _bfd_generic_link_output_symbols (bfd *output_bfd, 2032 bfd *input_bfd, 2033 struct bfd_link_info *info, 2034 size_t *psymalloc) 2035 { 2036 asymbol **sym_ptr; 2037 asymbol **sym_end; 2038 2039 if (!bfd_generic_link_read_symbols (input_bfd)) 2040 return FALSE; 2041 2042 /* Create a filename symbol if we are supposed to. */ 2043 if (info->create_object_symbols_section != NULL) 2044 { 2045 asection *sec; 2046 2047 for (sec = input_bfd->sections; sec != NULL; sec = sec->next) 2048 { 2049 if (sec->output_section == info->create_object_symbols_section) 2050 { 2051 asymbol *newsym; 2052 2053 newsym = bfd_make_empty_symbol (input_bfd); 2054 if (!newsym) 2055 return FALSE; 2056 newsym->name = input_bfd->filename; 2057 newsym->value = 0; 2058 newsym->flags = BSF_LOCAL | BSF_FILE; 2059 newsym->section = sec; 2060 2061 if (! generic_add_output_symbol (output_bfd, psymalloc, 2062 newsym)) 2063 return FALSE; 2064 2065 break; 2066 } 2067 } 2068 } 2069 2070 /* Adjust the values of the globally visible symbols, and write out 2071 local symbols. */ 2072 sym_ptr = _bfd_generic_link_get_symbols (input_bfd); 2073 sym_end = sym_ptr + _bfd_generic_link_get_symcount (input_bfd); 2074 for (; sym_ptr < sym_end; sym_ptr++) 2075 { 2076 asymbol *sym; 2077 struct generic_link_hash_entry *h; 2078 bfd_boolean output; 2079 2080 h = NULL; 2081 sym = *sym_ptr; 2082 if ((sym->flags & (BSF_INDIRECT 2083 | BSF_WARNING 2084 | BSF_GLOBAL 2085 | BSF_CONSTRUCTOR 2086 | BSF_WEAK)) != 0 2087 || bfd_is_und_section (bfd_get_section (sym)) 2088 || bfd_is_com_section (bfd_get_section (sym)) 2089 || bfd_is_ind_section (bfd_get_section (sym))) 2090 { 2091 if (sym->udata.p != NULL) 2092 h = (struct generic_link_hash_entry *) sym->udata.p; 2093 else if ((sym->flags & BSF_CONSTRUCTOR) != 0) 2094 { 2095 /* This case normally means that the main linker code 2096 deliberately ignored this constructor symbol. We 2097 should just pass it through. This will screw up if 2098 the constructor symbol is from a different, 2099 non-generic, object file format, but the case will 2100 only arise when linking with -r, which will probably 2101 fail anyhow, since there will be no way to represent 2102 the relocs in the output format being used. */ 2103 h = NULL; 2104 } 2105 else if (bfd_is_und_section (bfd_get_section (sym))) 2106 h = ((struct generic_link_hash_entry *) 2107 bfd_wrapped_link_hash_lookup (output_bfd, info, 2108 bfd_asymbol_name (sym), 2109 FALSE, FALSE, TRUE)); 2110 else 2111 h = _bfd_generic_link_hash_lookup (_bfd_generic_hash_table (info), 2112 bfd_asymbol_name (sym), 2113 FALSE, FALSE, TRUE); 2114 2115 if (h != NULL) 2116 { 2117 /* Force all references to this symbol to point to 2118 the same area in memory. It is possible that 2119 this routine will be called with a hash table 2120 other than a generic hash table, so we double 2121 check that. */ 2122 if (info->output_bfd->xvec == input_bfd->xvec) 2123 { 2124 if (h->sym != NULL) 2125 *sym_ptr = sym = h->sym; 2126 } 2127 2128 switch (h->root.type) 2129 { 2130 default: 2131 case bfd_link_hash_new: 2132 abort (); 2133 case bfd_link_hash_undefined: 2134 break; 2135 case bfd_link_hash_undefweak: 2136 sym->flags |= BSF_WEAK; 2137 break; 2138 case bfd_link_hash_indirect: 2139 h = (struct generic_link_hash_entry *) h->root.u.i.link; 2140 /* fall through */ 2141 case bfd_link_hash_defined: 2142 sym->flags |= BSF_GLOBAL; 2143 sym->flags &=~ BSF_CONSTRUCTOR; 2144 sym->value = h->root.u.def.value; 2145 sym->section = h->root.u.def.section; 2146 break; 2147 case bfd_link_hash_defweak: 2148 sym->flags |= BSF_WEAK; 2149 sym->flags &=~ BSF_CONSTRUCTOR; 2150 sym->value = h->root.u.def.value; 2151 sym->section = h->root.u.def.section; 2152 break; 2153 case bfd_link_hash_common: 2154 sym->value = h->root.u.c.size; 2155 sym->flags |= BSF_GLOBAL; 2156 if (! bfd_is_com_section (sym->section)) 2157 { 2158 BFD_ASSERT (bfd_is_und_section (sym->section)); 2159 sym->section = bfd_com_section_ptr; 2160 } 2161 /* We do not set the section of the symbol to 2162 h->root.u.c.p->section. That value was saved so 2163 that we would know where to allocate the symbol 2164 if it was defined. In this case the type is 2165 still bfd_link_hash_common, so we did not define 2166 it, so we do not want to use that section. */ 2167 break; 2168 } 2169 } 2170 } 2171 2172 /* This switch is straight from the old code in 2173 write_file_locals in ldsym.c. */ 2174 if (info->strip == strip_all 2175 || (info->strip == strip_some 2176 && bfd_hash_lookup (info->keep_hash, bfd_asymbol_name (sym), 2177 FALSE, FALSE) == NULL)) 2178 output = FALSE; 2179 else if ((sym->flags & (BSF_GLOBAL | BSF_WEAK)) != 0) 2180 { 2181 /* If this symbol is marked as occurring now, rather 2182 than at the end, output it now. This is used for 2183 COFF C_EXT FCN symbols. FIXME: There must be a 2184 better way. */ 2185 if (bfd_asymbol_bfd (sym) == input_bfd 2186 && (sym->flags & BSF_NOT_AT_END) != 0) 2187 output = TRUE; 2188 else 2189 output = FALSE; 2190 } 2191 else if (bfd_is_ind_section (sym->section)) 2192 output = FALSE; 2193 else if ((sym->flags & BSF_DEBUGGING) != 0) 2194 { 2195 if (info->strip == strip_none) 2196 output = TRUE; 2197 else 2198 output = FALSE; 2199 } 2200 else if (bfd_is_und_section (sym->section) 2201 || bfd_is_com_section (sym->section)) 2202 output = FALSE; 2203 else if ((sym->flags & BSF_LOCAL) != 0) 2204 { 2205 if ((sym->flags & BSF_WARNING) != 0) 2206 output = FALSE; 2207 else 2208 { 2209 switch (info->discard) 2210 { 2211 default: 2212 case discard_all: 2213 output = FALSE; 2214 break; 2215 case discard_sec_merge: 2216 output = TRUE; 2217 if (info->relocatable 2218 || ! (sym->section->flags & SEC_MERGE)) 2219 break; 2220 /* FALLTHROUGH */ 2221 case discard_l: 2222 if (bfd_is_local_label (input_bfd, sym)) 2223 output = FALSE; 2224 else 2225 output = TRUE; 2226 break; 2227 case discard_none: 2228 output = TRUE; 2229 break; 2230 } 2231 } 2232 } 2233 else if ((sym->flags & BSF_CONSTRUCTOR)) 2234 { 2235 if (info->strip != strip_all) 2236 output = TRUE; 2237 else 2238 output = FALSE; 2239 } 2240 else if (sym->flags == 0 2241 && (sym->section->owner->flags & BFD_PLUGIN) != 0) 2242 /* LTO doesn't set symbol information. We get here with the 2243 generic linker for a symbol that was "common" but no longer 2244 needs to be global. */ 2245 output = FALSE; 2246 else 2247 abort (); 2248 2249 /* If this symbol is in a section which is not being included 2250 in the output file, then we don't want to output the 2251 symbol. */ 2252 if (!bfd_is_abs_section (sym->section) 2253 && bfd_section_removed_from_list (output_bfd, 2254 sym->section->output_section)) 2255 output = FALSE; 2256 2257 if (output) 2258 { 2259 if (! generic_add_output_symbol (output_bfd, psymalloc, sym)) 2260 return FALSE; 2261 if (h != NULL) 2262 h->written = TRUE; 2263 } 2264 } 2265 2266 return TRUE; 2267 } 2268 2269 /* Set the section and value of a generic BFD symbol based on a linker 2270 hash table entry. */ 2271 2272 static void 2273 set_symbol_from_hash (asymbol *sym, struct bfd_link_hash_entry *h) 2274 { 2275 switch (h->type) 2276 { 2277 default: 2278 abort (); 2279 break; 2280 case bfd_link_hash_new: 2281 /* This can happen when a constructor symbol is seen but we are 2282 not building constructors. */ 2283 if (sym->section != NULL) 2284 { 2285 BFD_ASSERT ((sym->flags & BSF_CONSTRUCTOR) != 0); 2286 } 2287 else 2288 { 2289 sym->flags |= BSF_CONSTRUCTOR; 2290 sym->section = bfd_abs_section_ptr; 2291 sym->value = 0; 2292 } 2293 break; 2294 case bfd_link_hash_undefined: 2295 sym->section = bfd_und_section_ptr; 2296 sym->value = 0; 2297 break; 2298 case bfd_link_hash_undefweak: 2299 sym->section = bfd_und_section_ptr; 2300 sym->value = 0; 2301 sym->flags |= BSF_WEAK; 2302 break; 2303 case bfd_link_hash_defined: 2304 sym->section = h->u.def.section; 2305 sym->value = h->u.def.value; 2306 break; 2307 case bfd_link_hash_defweak: 2308 sym->flags |= BSF_WEAK; 2309 sym->section = h->u.def.section; 2310 sym->value = h->u.def.value; 2311 break; 2312 case bfd_link_hash_common: 2313 sym->value = h->u.c.size; 2314 if (sym->section == NULL) 2315 sym->section = bfd_com_section_ptr; 2316 else if (! bfd_is_com_section (sym->section)) 2317 { 2318 BFD_ASSERT (bfd_is_und_section (sym->section)); 2319 sym->section = bfd_com_section_ptr; 2320 } 2321 /* Do not set the section; see _bfd_generic_link_output_symbols. */ 2322 break; 2323 case bfd_link_hash_indirect: 2324 case bfd_link_hash_warning: 2325 /* FIXME: What should we do here? */ 2326 break; 2327 } 2328 } 2329 2330 /* Write out a global symbol, if it hasn't already been written out. 2331 This is called for each symbol in the hash table. */ 2332 2333 bfd_boolean 2334 _bfd_generic_link_write_global_symbol (struct generic_link_hash_entry *h, 2335 void *data) 2336 { 2337 struct generic_write_global_symbol_info *wginfo = 2338 (struct generic_write_global_symbol_info *) data; 2339 asymbol *sym; 2340 2341 if (h->written) 2342 return TRUE; 2343 2344 h->written = TRUE; 2345 2346 if (wginfo->info->strip == strip_all 2347 || (wginfo->info->strip == strip_some 2348 && bfd_hash_lookup (wginfo->info->keep_hash, h->root.root.string, 2349 FALSE, FALSE) == NULL)) 2350 return TRUE; 2351 2352 if (h->sym != NULL) 2353 sym = h->sym; 2354 else 2355 { 2356 sym = bfd_make_empty_symbol (wginfo->output_bfd); 2357 if (!sym) 2358 return FALSE; 2359 sym->name = h->root.root.string; 2360 sym->flags = 0; 2361 } 2362 2363 set_symbol_from_hash (sym, &h->root); 2364 2365 sym->flags |= BSF_GLOBAL; 2366 2367 if (! generic_add_output_symbol (wginfo->output_bfd, wginfo->psymalloc, 2368 sym)) 2369 { 2370 /* FIXME: No way to return failure. */ 2371 abort (); 2372 } 2373 2374 return TRUE; 2375 } 2376 2377 /* Create a relocation. */ 2378 2379 bfd_boolean 2380 _bfd_generic_reloc_link_order (bfd *abfd, 2381 struct bfd_link_info *info, 2382 asection *sec, 2383 struct bfd_link_order *link_order) 2384 { 2385 arelent *r; 2386 2387 if (! info->relocatable) 2388 abort (); 2389 if (sec->orelocation == NULL) 2390 abort (); 2391 2392 r = (arelent *) bfd_alloc (abfd, sizeof (arelent)); 2393 if (r == NULL) 2394 return FALSE; 2395 2396 r->address = link_order->offset; 2397 r->howto = bfd_reloc_type_lookup (abfd, link_order->u.reloc.p->reloc); 2398 if (r->howto == 0) 2399 { 2400 bfd_set_error (bfd_error_bad_value); 2401 return FALSE; 2402 } 2403 2404 /* Get the symbol to use for the relocation. */ 2405 if (link_order->type == bfd_section_reloc_link_order) 2406 r->sym_ptr_ptr = link_order->u.reloc.p->u.section->symbol_ptr_ptr; 2407 else 2408 { 2409 struct generic_link_hash_entry *h; 2410 2411 h = ((struct generic_link_hash_entry *) 2412 bfd_wrapped_link_hash_lookup (abfd, info, 2413 link_order->u.reloc.p->u.name, 2414 FALSE, FALSE, TRUE)); 2415 if (h == NULL 2416 || ! h->written) 2417 { 2418 if (! ((*info->callbacks->unattached_reloc) 2419 (info, link_order->u.reloc.p->u.name, NULL, NULL, 0))) 2420 return FALSE; 2421 bfd_set_error (bfd_error_bad_value); 2422 return FALSE; 2423 } 2424 r->sym_ptr_ptr = &h->sym; 2425 } 2426 2427 /* If this is an inplace reloc, write the addend to the object file. 2428 Otherwise, store it in the reloc addend. */ 2429 if (! r->howto->partial_inplace) 2430 r->addend = link_order->u.reloc.p->addend; 2431 else 2432 { 2433 bfd_size_type size; 2434 bfd_reloc_status_type rstat; 2435 bfd_byte *buf; 2436 bfd_boolean ok; 2437 file_ptr loc; 2438 2439 size = bfd_get_reloc_size (r->howto); 2440 buf = (bfd_byte *) bfd_zmalloc (size); 2441 if (buf == NULL) 2442 return FALSE; 2443 rstat = _bfd_relocate_contents (r->howto, abfd, 2444 (bfd_vma) link_order->u.reloc.p->addend, 2445 buf); 2446 switch (rstat) 2447 { 2448 case bfd_reloc_ok: 2449 break; 2450 default: 2451 case bfd_reloc_outofrange: 2452 abort (); 2453 case bfd_reloc_overflow: 2454 if (! ((*info->callbacks->reloc_overflow) 2455 (info, NULL, 2456 (link_order->type == bfd_section_reloc_link_order 2457 ? bfd_section_name (abfd, link_order->u.reloc.p->u.section) 2458 : link_order->u.reloc.p->u.name), 2459 r->howto->name, link_order->u.reloc.p->addend, 2460 NULL, NULL, 0))) 2461 { 2462 free (buf); 2463 return FALSE; 2464 } 2465 break; 2466 } 2467 loc = link_order->offset * bfd_octets_per_byte (abfd); 2468 ok = bfd_set_section_contents (abfd, sec, buf, loc, size); 2469 free (buf); 2470 if (! ok) 2471 return FALSE; 2472 2473 r->addend = 0; 2474 } 2475 2476 sec->orelocation[sec->reloc_count] = r; 2477 ++sec->reloc_count; 2478 2479 return TRUE; 2480 } 2481 2482 /* Allocate a new link_order for a section. */ 2484 2485 struct bfd_link_order * 2486 bfd_new_link_order (bfd *abfd, asection *section) 2487 { 2488 bfd_size_type amt = sizeof (struct bfd_link_order); 2489 struct bfd_link_order *new_lo; 2490 2491 new_lo = (struct bfd_link_order *) bfd_zalloc (abfd, amt); 2492 if (!new_lo) 2493 return NULL; 2494 2495 new_lo->type = bfd_undefined_link_order; 2496 2497 if (section->map_tail.link_order != NULL) 2498 section->map_tail.link_order->next = new_lo; 2499 else 2500 section->map_head.link_order = new_lo; 2501 section->map_tail.link_order = new_lo; 2502 2503 return new_lo; 2504 } 2505 2506 /* Default link order processing routine. Note that we can not handle 2507 the reloc_link_order types here, since they depend upon the details 2508 of how the particular backends generates relocs. */ 2509 2510 bfd_boolean 2511 _bfd_default_link_order (bfd *abfd, 2512 struct bfd_link_info *info, 2513 asection *sec, 2514 struct bfd_link_order *link_order) 2515 { 2516 switch (link_order->type) 2517 { 2518 case bfd_undefined_link_order: 2519 case bfd_section_reloc_link_order: 2520 case bfd_symbol_reloc_link_order: 2521 default: 2522 abort (); 2523 case bfd_indirect_link_order: 2524 return default_indirect_link_order (abfd, info, sec, link_order, 2525 FALSE); 2526 case bfd_data_link_order: 2527 return default_data_link_order (abfd, info, sec, link_order); 2528 } 2529 } 2530 2531 /* Default routine to handle a bfd_data_link_order. */ 2532 2533 static bfd_boolean 2534 default_data_link_order (bfd *abfd, 2535 struct bfd_link_info *info ATTRIBUTE_UNUSED, 2536 asection *sec, 2537 struct bfd_link_order *link_order) 2538 { 2539 bfd_size_type size; 2540 size_t fill_size; 2541 bfd_byte *fill; 2542 file_ptr loc; 2543 bfd_boolean result; 2544 2545 BFD_ASSERT ((sec->flags & SEC_HAS_CONTENTS) != 0); 2546 2547 size = link_order->size; 2548 if (size == 0) 2549 return TRUE; 2550 2551 fill = link_order->u.data.contents; 2552 fill_size = link_order->u.data.size; 2553 if (fill_size == 0) 2554 { 2555 fill = abfd->arch_info->fill (size, bfd_big_endian (abfd), 2556 (sec->flags & SEC_CODE) != 0); 2557 if (fill == NULL) 2558 return FALSE; 2559 } 2560 else if (fill_size < size) 2561 { 2562 bfd_byte *p; 2563 fill = (bfd_byte *) bfd_malloc (size); 2564 if (fill == NULL) 2565 return FALSE; 2566 p = fill; 2567 if (fill_size == 1) 2568 memset (p, (int) link_order->u.data.contents[0], (size_t) size); 2569 else 2570 { 2571 do 2572 { 2573 memcpy (p, link_order->u.data.contents, fill_size); 2574 p += fill_size; 2575 size -= fill_size; 2576 } 2577 while (size >= fill_size); 2578 if (size != 0) 2579 memcpy (p, link_order->u.data.contents, (size_t) size); 2580 size = link_order->size; 2581 } 2582 } 2583 2584 loc = link_order->offset * bfd_octets_per_byte (abfd); 2585 result = bfd_set_section_contents (abfd, sec, fill, loc, size); 2586 2587 if (fill != link_order->u.data.contents) 2588 free (fill); 2589 return result; 2590 } 2591 2592 /* Default routine to handle a bfd_indirect_link_order. */ 2593 2594 static bfd_boolean 2595 default_indirect_link_order (bfd *output_bfd, 2596 struct bfd_link_info *info, 2597 asection *output_section, 2598 struct bfd_link_order *link_order, 2599 bfd_boolean generic_linker) 2600 { 2601 asection *input_section; 2602 bfd *input_bfd; 2603 bfd_byte *contents = NULL; 2604 bfd_byte *new_contents; 2605 bfd_size_type sec_size; 2606 file_ptr loc; 2607 2608 BFD_ASSERT ((output_section->flags & SEC_HAS_CONTENTS) != 0); 2609 2610 input_section = link_order->u.indirect.section; 2611 input_bfd = input_section->owner; 2612 if (input_section->size == 0) 2613 return TRUE; 2614 2615 BFD_ASSERT (input_section->output_section == output_section); 2616 BFD_ASSERT (input_section->output_offset == link_order->offset); 2617 BFD_ASSERT (input_section->size == link_order->size); 2618 2619 if (info->relocatable 2620 && input_section->reloc_count > 0 2621 && output_section->orelocation == NULL) 2622 { 2623 /* Space has not been allocated for the output relocations. 2624 This can happen when we are called by a specific backend 2625 because somebody is attempting to link together different 2626 types of object files. Handling this case correctly is 2627 difficult, and sometimes impossible. */ 2628 (*_bfd_error_handler) 2629 (_("Attempt to do relocatable link with %s input and %s output"), 2630 bfd_get_target (input_bfd), bfd_get_target (output_bfd)); 2631 bfd_set_error (bfd_error_wrong_format); 2632 return FALSE; 2633 } 2634 2635 if (! generic_linker) 2636 { 2637 asymbol **sympp; 2638 asymbol **symppend; 2639 2640 /* Get the canonical symbols. The generic linker will always 2641 have retrieved them by this point, but we are being called by 2642 a specific linker, presumably because we are linking 2643 different types of object files together. */ 2644 if (!bfd_generic_link_read_symbols (input_bfd)) 2645 return FALSE; 2646 2647 /* Since we have been called by a specific linker, rather than 2648 the generic linker, the values of the symbols will not be 2649 right. They will be the values as seen in the input file, 2650 not the values of the final link. We need to fix them up 2651 before we can relocate the section. */ 2652 sympp = _bfd_generic_link_get_symbols (input_bfd); 2653 symppend = sympp + _bfd_generic_link_get_symcount (input_bfd); 2654 for (; sympp < symppend; sympp++) 2655 { 2656 asymbol *sym; 2657 struct bfd_link_hash_entry *h; 2658 2659 sym = *sympp; 2660 2661 if ((sym->flags & (BSF_INDIRECT 2662 | BSF_WARNING 2663 | BSF_GLOBAL 2664 | BSF_CONSTRUCTOR 2665 | BSF_WEAK)) != 0 2666 || bfd_is_und_section (bfd_get_section (sym)) 2667 || bfd_is_com_section (bfd_get_section (sym)) 2668 || bfd_is_ind_section (bfd_get_section (sym))) 2669 { 2670 /* sym->udata may have been set by 2671 generic_link_add_symbol_list. */ 2672 if (sym->udata.p != NULL) 2673 h = (struct bfd_link_hash_entry *) sym->udata.p; 2674 else if (bfd_is_und_section (bfd_get_section (sym))) 2675 h = bfd_wrapped_link_hash_lookup (output_bfd, info, 2676 bfd_asymbol_name (sym), 2677 FALSE, FALSE, TRUE); 2678 else 2679 h = bfd_link_hash_lookup (info->hash, 2680 bfd_asymbol_name (sym), 2681 FALSE, FALSE, TRUE); 2682 if (h != NULL) 2683 set_symbol_from_hash (sym, h); 2684 } 2685 } 2686 } 2687 2688 if ((output_section->flags & (SEC_GROUP | SEC_LINKER_CREATED)) == SEC_GROUP 2689 && input_section->size != 0) 2690 { 2691 /* Group section contents are set by bfd_elf_set_group_contents. */ 2692 if (!output_bfd->output_has_begun) 2693 { 2694 /* FIXME: This hack ensures bfd_elf_set_group_contents is called. */ 2695 if (!bfd_set_section_contents (output_bfd, output_section, "", 0, 1)) 2696 goto error_return; 2697 } 2698 new_contents = output_section->contents; 2699 BFD_ASSERT (new_contents != NULL); 2700 BFD_ASSERT (input_section->output_offset == 0); 2701 } 2702 else 2703 { 2704 /* Get and relocate the section contents. */ 2705 sec_size = (input_section->rawsize > input_section->size 2706 ? input_section->rawsize 2707 : input_section->size); 2708 contents = (bfd_byte *) bfd_malloc (sec_size); 2709 if (contents == NULL && sec_size != 0) 2710 goto error_return; 2711 new_contents = (bfd_get_relocated_section_contents 2712 (output_bfd, info, link_order, contents, 2713 info->relocatable, 2714 _bfd_generic_link_get_symbols (input_bfd))); 2715 if (!new_contents) 2716 goto error_return; 2717 } 2718 2719 /* Output the section contents. */ 2720 loc = input_section->output_offset * bfd_octets_per_byte (output_bfd); 2721 if (! bfd_set_section_contents (output_bfd, output_section, 2722 new_contents, loc, input_section->size)) 2723 goto error_return; 2724 2725 if (contents != NULL) 2726 free (contents); 2727 return TRUE; 2728 2729 error_return: 2730 if (contents != NULL) 2731 free (contents); 2732 return FALSE; 2733 } 2734 2735 /* A little routine to count the number of relocs in a link_order 2736 list. */ 2737 2738 unsigned int 2739 _bfd_count_link_order_relocs (struct bfd_link_order *link_order) 2740 { 2741 register unsigned int c; 2742 register struct bfd_link_order *l; 2743 2744 c = 0; 2745 for (l = link_order; l != NULL; l = l->next) 2746 { 2747 if (l->type == bfd_section_reloc_link_order 2748 || l->type == bfd_symbol_reloc_link_order) 2749 ++c; 2750 } 2751 2752 return c; 2753 } 2754 2755 /* 2756 FUNCTION 2757 bfd_link_split_section 2758 2759 SYNOPSIS 2760 bfd_boolean bfd_link_split_section (bfd *abfd, asection *sec); 2761 2762 DESCRIPTION 2763 Return nonzero if @var{sec} should be split during a 2764 reloceatable or final link. 2765 2766 .#define bfd_link_split_section(abfd, sec) \ 2767 . BFD_SEND (abfd, _bfd_link_split_section, (abfd, sec)) 2768 . 2769 2770 */ 2771 2772 bfd_boolean 2773 _bfd_generic_link_split_section (bfd *abfd ATTRIBUTE_UNUSED, 2774 asection *sec ATTRIBUTE_UNUSED) 2775 { 2776 return FALSE; 2777 } 2778 2779 /* 2780 FUNCTION 2781 bfd_section_already_linked 2782 2783 SYNOPSIS 2784 bfd_boolean bfd_section_already_linked (bfd *abfd, 2785 asection *sec, 2786 struct bfd_link_info *info); 2787 2788 DESCRIPTION 2789 Check if @var{data} has been already linked during a reloceatable 2790 or final link. Return TRUE if it has. 2791 2792 .#define bfd_section_already_linked(abfd, sec, info) \ 2793 . BFD_SEND (abfd, _section_already_linked, (abfd, sec, info)) 2794 . 2795 2796 */ 2797 2798 /* Sections marked with the SEC_LINK_ONCE flag should only be linked 2799 once into the output. This routine checks each section, and 2800 arrange to discard it if a section of the same name has already 2801 been linked. This code assumes that all relevant sections have the 2802 SEC_LINK_ONCE flag set; that is, it does not depend solely upon the 2803 section name. bfd_section_already_linked is called via 2804 bfd_map_over_sections. */ 2805 2806 /* The hash table. */ 2807 2808 static struct bfd_hash_table _bfd_section_already_linked_table; 2809 2810 /* Support routines for the hash table used by section_already_linked, 2811 initialize the table, traverse, lookup, fill in an entry and remove 2812 the table. */ 2813 2814 void 2815 bfd_section_already_linked_table_traverse 2816 (bfd_boolean (*func) (struct bfd_section_already_linked_hash_entry *, 2817 void *), void *info) 2818 { 2819 bfd_hash_traverse (&_bfd_section_already_linked_table, 2820 (bfd_boolean (*) (struct bfd_hash_entry *, 2821 void *)) func, 2822 info); 2823 } 2824 2825 struct bfd_section_already_linked_hash_entry * 2826 bfd_section_already_linked_table_lookup (const char *name) 2827 { 2828 return ((struct bfd_section_already_linked_hash_entry *) 2829 bfd_hash_lookup (&_bfd_section_already_linked_table, name, 2830 TRUE, FALSE)); 2831 } 2832 2833 bfd_boolean 2834 bfd_section_already_linked_table_insert 2835 (struct bfd_section_already_linked_hash_entry *already_linked_list, 2836 asection *sec) 2837 { 2838 struct bfd_section_already_linked *l; 2839 2840 /* Allocate the memory from the same obstack as the hash table is 2841 kept in. */ 2842 l = (struct bfd_section_already_linked *) 2843 bfd_hash_allocate (&_bfd_section_already_linked_table, sizeof *l); 2844 if (l == NULL) 2845 return FALSE; 2846 l->sec = sec; 2847 l->next = already_linked_list->entry; 2848 already_linked_list->entry = l; 2849 return TRUE; 2850 } 2851 2852 static struct bfd_hash_entry * 2853 already_linked_newfunc (struct bfd_hash_entry *entry ATTRIBUTE_UNUSED, 2854 struct bfd_hash_table *table, 2855 const char *string ATTRIBUTE_UNUSED) 2856 { 2857 struct bfd_section_already_linked_hash_entry *ret = 2858 (struct bfd_section_already_linked_hash_entry *) 2859 bfd_hash_allocate (table, sizeof *ret); 2860 2861 if (ret == NULL) 2862 return NULL; 2863 2864 ret->entry = NULL; 2865 2866 return &ret->root; 2867 } 2868 2869 bfd_boolean 2870 bfd_section_already_linked_table_init (void) 2871 { 2872 return bfd_hash_table_init_n (&_bfd_section_already_linked_table, 2873 already_linked_newfunc, 2874 sizeof (struct bfd_section_already_linked_hash_entry), 2875 42); 2876 } 2877 2878 void 2879 bfd_section_already_linked_table_free (void) 2880 { 2881 bfd_hash_table_free (&_bfd_section_already_linked_table); 2882 } 2883 2884 /* Report warnings as appropriate for duplicate section SEC. 2885 Return FALSE if we decide to keep SEC after all. */ 2886 2887 bfd_boolean 2888 _bfd_handle_already_linked (asection *sec, 2889 struct bfd_section_already_linked *l, 2890 struct bfd_link_info *info) 2891 { 2892 switch (sec->flags & SEC_LINK_DUPLICATES) 2893 { 2894 default: 2895 abort (); 2896 2897 case SEC_LINK_DUPLICATES_DISCARD: 2898 /* If we found an LTO IR match for this comdat group on 2899 the first pass, replace it with the LTO output on the 2900 second pass. We can't simply choose real object 2901 files over IR because the first pass may contain a 2902 mix of LTO and normal objects and we must keep the 2903 first match, be it IR or real. */ 2904 if (info->loading_lto_outputs 2905 && (l->sec->owner->flags & BFD_PLUGIN) != 0) 2906 { 2907 l->sec = sec; 2908 return FALSE; 2909 } 2910 break; 2911 2912 case SEC_LINK_DUPLICATES_ONE_ONLY: 2913 info->callbacks->einfo 2914 (_("%B: ignoring duplicate section `%A'\n"), 2915 sec->owner, sec); 2916 break; 2917 2918 case SEC_LINK_DUPLICATES_SAME_SIZE: 2919 if ((l->sec->owner->flags & BFD_PLUGIN) != 0) 2920 ; 2921 else if (sec->size != l->sec->size) 2922 info->callbacks->einfo 2923 (_("%B: duplicate section `%A' has different size\n"), 2924 sec->owner, sec); 2925 break; 2926 2927 case SEC_LINK_DUPLICATES_SAME_CONTENTS: 2928 if ((l->sec->owner->flags & BFD_PLUGIN) != 0) 2929 ; 2930 else if (sec->size != l->sec->size) 2931 info->callbacks->einfo 2932 (_("%B: duplicate section `%A' has different size\n"), 2933 sec->owner, sec); 2934 else if (sec->size != 0) 2935 { 2936 bfd_byte *sec_contents, *l_sec_contents = NULL; 2937 2938 if (!bfd_malloc_and_get_section (sec->owner, sec, &sec_contents)) 2939 info->callbacks->einfo 2940 (_("%B: could not read contents of section `%A'\n"), 2941 sec->owner, sec); 2942 else if (!bfd_malloc_and_get_section (l->sec->owner, l->sec, 2943 &l_sec_contents)) 2944 info->callbacks->einfo 2945 (_("%B: could not read contents of section `%A'\n"), 2946 l->sec->owner, l->sec); 2947 else if (memcmp (sec_contents, l_sec_contents, sec->size) != 0) 2948 info->callbacks->einfo 2949 (_("%B: duplicate section `%A' has different contents\n"), 2950 sec->owner, sec); 2951 2952 if (sec_contents) 2953 free (sec_contents); 2954 if (l_sec_contents) 2955 free (l_sec_contents); 2956 } 2957 break; 2958 } 2959 2960 /* Set the output_section field so that lang_add_section 2961 does not create a lang_input_section structure for this 2962 section. Since there might be a symbol in the section 2963 being discarded, we must retain a pointer to the section 2964 which we are really going to use. */ 2965 sec->output_section = bfd_abs_section_ptr; 2966 sec->kept_section = l->sec; 2967 return TRUE; 2968 } 2969 2970 /* This is used on non-ELF inputs. */ 2971 2972 bfd_boolean 2973 _bfd_generic_section_already_linked (bfd *abfd ATTRIBUTE_UNUSED, 2974 asection *sec, 2975 struct bfd_link_info *info) 2976 { 2977 const char *name; 2978 struct bfd_section_already_linked *l; 2979 struct bfd_section_already_linked_hash_entry *already_linked_list; 2980 2981 if ((sec->flags & SEC_LINK_ONCE) == 0) 2982 return FALSE; 2983 2984 /* The generic linker doesn't handle section groups. */ 2985 if ((sec->flags & SEC_GROUP) != 0) 2986 return FALSE; 2987 2988 /* FIXME: When doing a relocatable link, we may have trouble 2989 copying relocations in other sections that refer to local symbols 2990 in the section being discarded. Those relocations will have to 2991 be converted somehow; as of this writing I'm not sure that any of 2992 the backends handle that correctly. 2993 2994 It is tempting to instead not discard link once sections when 2995 doing a relocatable link (technically, they should be discarded 2996 whenever we are building constructors). However, that fails, 2997 because the linker winds up combining all the link once sections 2998 into a single large link once section, which defeats the purpose 2999 of having link once sections in the first place. */ 3000 3001 name = bfd_get_section_name (abfd, sec); 3002 3003 already_linked_list = bfd_section_already_linked_table_lookup (name); 3004 3005 l = already_linked_list->entry; 3006 if (l != NULL) 3007 { 3008 /* The section has already been linked. See if we should 3009 issue a warning. */ 3010 return _bfd_handle_already_linked (sec, l, info); 3011 } 3012 3013 /* This is the first section with this name. Record it. */ 3014 if (!bfd_section_already_linked_table_insert (already_linked_list, sec)) 3015 info->callbacks->einfo (_("%F%P: already_linked_table: %E\n")); 3016 return FALSE; 3017 } 3018 3019 /* Choose a neighbouring section to S in OBFD that will be output, or 3020 the absolute section if ADDR is out of bounds of the neighbours. */ 3021 3022 asection * 3023 _bfd_nearby_section (bfd *obfd, asection *s, bfd_vma addr) 3024 { 3025 asection *next, *prev, *best; 3026 3027 /* Find preceding kept section. */ 3028 for (prev = s->prev; prev != NULL; prev = prev->prev) 3029 if ((prev->flags & SEC_EXCLUDE) == 0 3030 && !bfd_section_removed_from_list (obfd, prev)) 3031 break; 3032 3033 /* Find following kept section. Start at prev->next because 3034 other sections may have been added after S was removed. */ 3035 if (s->prev != NULL) 3036 next = s->prev->next; 3037 else 3038 next = s->owner->sections; 3039 for (; next != NULL; next = next->next) 3040 if ((next->flags & SEC_EXCLUDE) == 0 3041 && !bfd_section_removed_from_list (obfd, next)) 3042 break; 3043 3044 /* Choose better of two sections, based on flags. The idea 3045 is to choose a section that will be in the same segment 3046 as S would have been if it was kept. */ 3047 best = next; 3048 if (prev == NULL) 3049 { 3050 if (next == NULL) 3051 best = bfd_abs_section_ptr; 3052 } 3053 else if (next == NULL) 3054 best = prev; 3055 else if (((prev->flags ^ next->flags) 3056 & (SEC_ALLOC | SEC_THREAD_LOCAL | SEC_LOAD)) != 0) 3057 { 3058 if (((next->flags ^ s->flags) 3059 & (SEC_ALLOC | SEC_THREAD_LOCAL)) != 0 3060 /* We prefer to choose a loaded section. Section S 3061 doesn't have SEC_LOAD set (it being excluded, that 3062 part of the flag processing didn't happen) so we 3063 can't compare that flag to those of NEXT and PREV. */ 3064 || ((prev->flags & SEC_LOAD) != 0 3065 && (next->flags & SEC_LOAD) == 0)) 3066 best = prev; 3067 } 3068 else if (((prev->flags ^ next->flags) & SEC_READONLY) != 0) 3069 { 3070 if (((next->flags ^ s->flags) & SEC_READONLY) != 0) 3071 best = prev; 3072 } 3073 else if (((prev->flags ^ next->flags) & SEC_CODE) != 0) 3074 { 3075 if (((next->flags ^ s->flags) & SEC_CODE) != 0) 3076 best = prev; 3077 } 3078 else 3079 { 3080 /* Flags we care about are the same. Prefer the following 3081 section if that will result in a positive valued sym. */ 3082 if (addr < next->vma) 3083 best = prev; 3084 } 3085 3086 return best; 3087 } 3088 3089 /* Convert symbols in excluded output sections to use a kept section. */ 3090 3091 static bfd_boolean 3092 fix_syms (struct bfd_link_hash_entry *h, void *data) 3093 { 3094 bfd *obfd = (bfd *) data; 3095 3096 if (h->type == bfd_link_hash_defined 3097 || h->type == bfd_link_hash_defweak) 3098 { 3099 asection *s = h->u.def.section; 3100 if (s != NULL 3101 && s->output_section != NULL 3102 && (s->output_section->flags & SEC_EXCLUDE) != 0 3103 && bfd_section_removed_from_list (obfd, s->output_section)) 3104 { 3105 asection *op; 3106 3107 h->u.def.value += s->output_offset + s->output_section->vma; 3108 op = _bfd_nearby_section (obfd, s->output_section, h->u.def.value); 3109 h->u.def.value -= op->vma; 3110 h->u.def.section = op; 3111 } 3112 } 3113 3114 return TRUE; 3115 } 3116 3117 void 3118 _bfd_fix_excluded_sec_syms (bfd *obfd, struct bfd_link_info *info) 3119 { 3120 bfd_link_hash_traverse (info->hash, fix_syms, obfd); 3121 } 3122 3123 /* 3124 FUNCTION 3125 bfd_generic_define_common_symbol 3126 3127 SYNOPSIS 3128 bfd_boolean bfd_generic_define_common_symbol 3129 (bfd *output_bfd, struct bfd_link_info *info, 3130 struct bfd_link_hash_entry *h); 3131 3132 DESCRIPTION 3133 Convert common symbol @var{h} into a defined symbol. 3134 Return TRUE on success and FALSE on failure. 3135 3136 .#define bfd_define_common_symbol(output_bfd, info, h) \ 3137 . BFD_SEND (output_bfd, _bfd_define_common_symbol, (output_bfd, info, h)) 3138 . 3139 */ 3140 3141 bfd_boolean 3142 bfd_generic_define_common_symbol (bfd *output_bfd, 3143 struct bfd_link_info *info ATTRIBUTE_UNUSED, 3144 struct bfd_link_hash_entry *h) 3145 { 3146 unsigned int power_of_two; 3147 bfd_vma alignment, size; 3148 asection *section; 3149 3150 BFD_ASSERT (h != NULL && h->type == bfd_link_hash_common); 3151 3152 size = h->u.c.size; 3153 power_of_two = h->u.c.p->alignment_power; 3154 section = h->u.c.p->section; 3155 3156 /* Increase the size of the section to align the common symbol. 3157 The alignment must be a power of two. */ 3158 alignment = bfd_octets_per_byte (output_bfd) << power_of_two; 3159 BFD_ASSERT (alignment != 0 && (alignment & -alignment) == alignment); 3160 section->size += alignment - 1; 3161 section->size &= -alignment; 3162 3163 /* Adjust the section's overall alignment if necessary. */ 3164 if (power_of_two > section->alignment_power) 3165 section->alignment_power = power_of_two; 3166 3167 /* Change the symbol from common to defined. */ 3168 h->type = bfd_link_hash_defined; 3169 h->u.def.section = section; 3170 h->u.def.value = section->size; 3171 3172 /* Increase the size of the section. */ 3173 section->size += size; 3174 3175 /* Make sure the section is allocated in memory, and make sure that 3176 it is no longer a common section. */ 3177 section->flags |= SEC_ALLOC; 3178 section->flags &= ~SEC_IS_COMMON; 3179 return TRUE; 3180 } 3181 3182 /* 3183 FUNCTION 3184 bfd_find_version_for_sym 3185 3186 SYNOPSIS 3187 struct bfd_elf_version_tree * bfd_find_version_for_sym 3188 (struct bfd_elf_version_tree *verdefs, 3189 const char *sym_name, bfd_boolean *hide); 3190 3191 DESCRIPTION 3192 Search an elf version script tree for symbol versioning 3193 info and export / don't-export status for a given symbol. 3194 Return non-NULL on success and NULL on failure; also sets 3195 the output @samp{hide} boolean parameter. 3196 3197 */ 3198 3199 struct bfd_elf_version_tree * 3200 bfd_find_version_for_sym (struct bfd_elf_version_tree *verdefs, 3201 const char *sym_name, 3202 bfd_boolean *hide) 3203 { 3204 struct bfd_elf_version_tree *t; 3205 struct bfd_elf_version_tree *local_ver, *global_ver, *exist_ver; 3206 struct bfd_elf_version_tree *star_local_ver, *star_global_ver; 3207 3208 local_ver = NULL; 3209 global_ver = NULL; 3210 star_local_ver = NULL; 3211 star_global_ver = NULL; 3212 exist_ver = NULL; 3213 for (t = verdefs; t != NULL; t = t->next) 3214 { 3215 if (t->globals.list != NULL) 3216 { 3217 struct bfd_elf_version_expr *d = NULL; 3218 3219 while ((d = (*t->match) (&t->globals, d, sym_name)) != NULL) 3220 { 3221 if (d->literal || strcmp (d->pattern, "*") != 0) 3222 global_ver = t; 3223 else 3224 star_global_ver = t; 3225 if (d->symver) 3226 exist_ver = t; 3227 d->script = 1; 3228 /* If the match is a wildcard pattern, keep looking for 3229 a more explicit, perhaps even local, match. */ 3230 if (d->literal) 3231 break; 3232 } 3233 3234 if (d != NULL) 3235 break; 3236 } 3237 3238 if (t->locals.list != NULL) 3239 { 3240 struct bfd_elf_version_expr *d = NULL; 3241 3242 while ((d = (*t->match) (&t->locals, d, sym_name)) != NULL) 3243 { 3244 if (d->literal || strcmp (d->pattern, "*") != 0) 3245 local_ver = t; 3246 else 3247 star_local_ver = t; 3248 /* If the match is a wildcard pattern, keep looking for 3249 a more explicit, perhaps even global, match. */ 3250 if (d->literal) 3251 { 3252 /* An exact match overrides a global wildcard. */ 3253 global_ver = NULL; 3254 star_global_ver = NULL; 3255 break; 3256 } 3257 } 3258 3259 if (d != NULL) 3260 break; 3261 } 3262 } 3263 3264 if (global_ver == NULL && local_ver == NULL) 3265 global_ver = star_global_ver; 3266 3267 if (global_ver != NULL) 3268 { 3269 /* If we already have a versioned symbol that matches the 3270 node for this symbol, then we don't want to create a 3271 duplicate from the unversioned symbol. Instead hide the 3272 unversioned symbol. */ 3273 *hide = exist_ver == global_ver; 3274 return global_ver; 3275 } 3276 3277 if (local_ver == NULL) 3278 local_ver = star_local_ver; 3279 3280 if (local_ver != NULL) 3281 { 3282 *hide = TRUE; 3283 return local_ver; 3284 } 3285 3286 return NULL; 3287 } 3288 3289 /* 3290 FUNCTION 3291 bfd_hide_sym_by_version 3292 3293 SYNOPSIS 3294 bfd_boolean bfd_hide_sym_by_version 3295 (struct bfd_elf_version_tree *verdefs, const char *sym_name); 3296 3297 DESCRIPTION 3298 Search an elf version script tree for symbol versioning 3299 info for a given symbol. Return TRUE if the symbol is hidden. 3300 3301 */ 3302 3303 bfd_boolean 3304 bfd_hide_sym_by_version (struct bfd_elf_version_tree *verdefs, 3305 const char *sym_name) 3306 { 3307 bfd_boolean hidden = FALSE; 3308 bfd_find_version_for_sym (verdefs, sym_name, &hidden); 3309 return hidden; 3310 } 3311
