1 /* linker.c -- BFD linker routines 2 Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 3 2003, 2004, 2005, 2006, 2007, 2008, 2009 4 Free Software Foundation, Inc. 5 Written by Steve Chamberlain and Ian Lance Taylor, Cygnus Support 6 7 This file is part of BFD, the Binary File Descriptor library. 8 9 This program is free software; you can redistribute it and/or modify 10 it under the terms of the GNU General Public License as published by 11 the Free Software Foundation; either version 3 of the License, or 12 (at your option) any later version. 13 14 This program is distributed in the hope that it will be useful, 15 but WITHOUT ANY WARRANTY; without even the implied warranty of 16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 GNU General Public License for more details. 18 19 You should have received a copy of the GNU General Public License 20 along with this program; if not, write to the Free Software 21 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, 22 MA 02110-1301, USA. */ 23 24 #include "sysdep.h" 25 #include "bfd.h" 26 #include "libbfd.h" 27 #include "bfdlink.h" 28 #include "genlink.h" 29 30 /* 31 SECTION 32 Linker Functions 33 34 @cindex Linker 35 The linker uses three special entry points in the BFD target 36 vector. It is not necessary to write special routines for 37 these entry points when creating a new BFD back end, since 38 generic versions are provided. However, writing them can 39 speed up linking and make it use significantly less runtime 40 memory. 41 42 The first routine creates a hash table used by the other 43 routines. The second routine adds the symbols from an object 44 file to the hash table. The third routine takes all the 45 object files and links them together to create the output 46 file. These routines are designed so that the linker proper 47 does not need to know anything about the symbols in the object 48 files that it is linking. The linker merely arranges the 49 sections as directed by the linker script and lets BFD handle 50 the details of symbols and relocs. 51 52 The second routine and third routines are passed a pointer to 53 a <<struct bfd_link_info>> structure (defined in 54 <<bfdlink.h>>) which holds information relevant to the link, 55 including the linker hash table (which was created by the 56 first routine) and a set of callback functions to the linker 57 proper. 58 59 The generic linker routines are in <<linker.c>>, and use the 60 header file <<genlink.h>>. As of this writing, the only back 61 ends which have implemented versions of these routines are 62 a.out (in <<aoutx.h>>) and ECOFF (in <<ecoff.c>>). The a.out 63 routines are used as examples throughout this section. 64 65 @menu 66 @* Creating a Linker Hash Table:: 67 @* Adding Symbols to the Hash Table:: 68 @* Performing the Final Link:: 69 @end menu 70 71 INODE 72 Creating a Linker Hash Table, Adding Symbols to the Hash Table, Linker Functions, Linker Functions 73 SUBSECTION 74 Creating a linker hash table 75 76 @cindex _bfd_link_hash_table_create in target vector 77 @cindex target vector (_bfd_link_hash_table_create) 78 The linker routines must create a hash table, which must be 79 derived from <<struct bfd_link_hash_table>> described in 80 <<bfdlink.c>>. @xref{Hash Tables}, for information on how to 81 create a derived hash table. This entry point is called using 82 the target vector of the linker output file. 83 84 The <<_bfd_link_hash_table_create>> entry point must allocate 85 and initialize an instance of the desired hash table. If the 86 back end does not require any additional information to be 87 stored with the entries in the hash table, the entry point may 88 simply create a <<struct bfd_link_hash_table>>. Most likely, 89 however, some additional information will be needed. 90 91 For example, with each entry in the hash table the a.out 92 linker keeps the index the symbol has in the final output file 93 (this index number is used so that when doing a relocatable 94 link the symbol index used in the output file can be quickly 95 filled in when copying over a reloc). The a.out linker code 96 defines the required structures and functions for a hash table 97 derived from <<struct bfd_link_hash_table>>. The a.out linker 98 hash table is created by the function 99 <<NAME(aout,link_hash_table_create)>>; it simply allocates 100 space for the hash table, initializes it, and returns a 101 pointer to it. 102 103 When writing the linker routines for a new back end, you will 104 generally not know exactly which fields will be required until 105 you have finished. You should simply create a new hash table 106 which defines no additional fields, and then simply add fields 107 as they become necessary. 108 109 INODE 110 Adding Symbols to the Hash Table, Performing the Final Link, Creating a Linker Hash Table, Linker Functions 111 SUBSECTION 112 Adding symbols to the hash table 113 114 @cindex _bfd_link_add_symbols in target vector 115 @cindex target vector (_bfd_link_add_symbols) 116 The linker proper will call the <<_bfd_link_add_symbols>> 117 entry point for each object file or archive which is to be 118 linked (typically these are the files named on the command 119 line, but some may also come from the linker script). The 120 entry point is responsible for examining the file. For an 121 object file, BFD must add any relevant symbol information to 122 the hash table. For an archive, BFD must determine which 123 elements of the archive should be used and adding them to the 124 link. 125 126 The a.out version of this entry point is 127 <<NAME(aout,link_add_symbols)>>. 128 129 @menu 130 @* Differing file formats:: 131 @* Adding symbols from an object file:: 132 @* Adding symbols from an archive:: 133 @end menu 134 135 INODE 136 Differing file formats, Adding symbols from an object file, Adding Symbols to the Hash Table, Adding Symbols to the Hash Table 137 SUBSUBSECTION 138 Differing file formats 139 140 Normally all the files involved in a link will be of the same 141 format, but it is also possible to link together different 142 format object files, and the back end must support that. The 143 <<_bfd_link_add_symbols>> entry point is called via the target 144 vector of the file to be added. This has an important 145 consequence: the function may not assume that the hash table 146 is the type created by the corresponding 147 <<_bfd_link_hash_table_create>> vector. All the 148 <<_bfd_link_add_symbols>> function can assume about the hash 149 table is that it is derived from <<struct 150 bfd_link_hash_table>>. 151 152 Sometimes the <<_bfd_link_add_symbols>> function must store 153 some information in the hash table entry to be used by the 154 <<_bfd_final_link>> function. In such a case the output bfd 155 xvec must be checked to make sure that the hash table was 156 created by an object file of the same format. 157 158 The <<_bfd_final_link>> routine must be prepared to handle a 159 hash entry without any extra information added by the 160 <<_bfd_link_add_symbols>> function. A hash entry without 161 extra information will also occur when the linker script 162 directs the linker to create a symbol. Note that, regardless 163 of how a hash table entry is added, all the fields will be 164 initialized to some sort of null value by the hash table entry 165 initialization function. 166 167 See <<ecoff_link_add_externals>> for an example of how to 168 check the output bfd before saving information (in this 169 case, the ECOFF external symbol debugging information) in a 170 hash table entry. 171 172 INODE 173 Adding symbols from an object file, Adding symbols from an archive, Differing file formats, Adding Symbols to the Hash Table 174 SUBSUBSECTION 175 Adding symbols from an object file 176 177 When the <<_bfd_link_add_symbols>> routine is passed an object 178 file, it must add all externally visible symbols in that 179 object file to the hash table. The actual work of adding the 180 symbol to the hash table is normally handled by the function 181 <<_bfd_generic_link_add_one_symbol>>. The 182 <<_bfd_link_add_symbols>> routine is responsible for reading 183 all the symbols from the object file and passing the correct 184 information to <<_bfd_generic_link_add_one_symbol>>. 185 186 The <<_bfd_link_add_symbols>> routine should not use 187 <<bfd_canonicalize_symtab>> to read the symbols. The point of 188 providing this routine is to avoid the overhead of converting 189 the symbols into generic <<asymbol>> structures. 190 191 @findex _bfd_generic_link_add_one_symbol 192 <<_bfd_generic_link_add_one_symbol>> handles the details of 193 combining common symbols, warning about multiple definitions, 194 and so forth. It takes arguments which describe the symbol to 195 add, notably symbol flags, a section, and an offset. The 196 symbol flags include such things as <<BSF_WEAK>> or 197 <<BSF_INDIRECT>>. The section is a section in the object 198 file, or something like <<bfd_und_section_ptr>> for an undefined 199 symbol or <<bfd_com_section_ptr>> for a common symbol. 200 201 If the <<_bfd_final_link>> routine is also going to need to 202 read the symbol information, the <<_bfd_link_add_symbols>> 203 routine should save it somewhere attached to the object file 204 BFD. However, the information should only be saved if the 205 <<keep_memory>> field of the <<info>> argument is TRUE, so 206 that the <<-no-keep-memory>> linker switch is effective. 207 208 The a.out function which adds symbols from an object file is 209 <<aout_link_add_object_symbols>>, and most of the interesting 210 work is in <<aout_link_add_symbols>>. The latter saves 211 pointers to the hash tables entries created by 212 <<_bfd_generic_link_add_one_symbol>> indexed by symbol number, 213 so that the <<_bfd_final_link>> routine does not have to call 214 the hash table lookup routine to locate the entry. 215 216 INODE 217 Adding symbols from an archive, , Adding symbols from an object file, Adding Symbols to the Hash Table 218 SUBSUBSECTION 219 Adding symbols from an archive 220 221 When the <<_bfd_link_add_symbols>> routine is passed an 222 archive, it must look through the symbols defined by the 223 archive and decide which elements of the archive should be 224 included in the link. For each such element it must call the 225 <<add_archive_element>> linker callback, and it must add the 226 symbols from the object file to the linker hash table. 227 228 @findex _bfd_generic_link_add_archive_symbols 229 In most cases the work of looking through the symbols in the 230 archive should be done by the 231 <<_bfd_generic_link_add_archive_symbols>> function. This 232 function builds a hash table from the archive symbol table and 233 looks through the list of undefined symbols to see which 234 elements should be included. 235 <<_bfd_generic_link_add_archive_symbols>> is passed a function 236 to call to make the final decision about adding an archive 237 element to the link and to do the actual work of adding the 238 symbols to the linker hash table. 239 240 The function passed to 241 <<_bfd_generic_link_add_archive_symbols>> must read the 242 symbols of the archive element and decide whether the archive 243 element should be included in the link. If the element is to 244 be included, the <<add_archive_element>> linker callback 245 routine must be called with the element as an argument, and 246 the elements symbols must be added to the linker hash table 247 just as though the element had itself been passed to the 248 <<_bfd_link_add_symbols>> function. 249 250 When the a.out <<_bfd_link_add_symbols>> function receives an 251 archive, it calls <<_bfd_generic_link_add_archive_symbols>> 252 passing <<aout_link_check_archive_element>> as the function 253 argument. <<aout_link_check_archive_element>> calls 254 <<aout_link_check_ar_symbols>>. If the latter decides to add 255 the element (an element is only added if it provides a real, 256 non-common, definition for a previously undefined or common 257 symbol) it calls the <<add_archive_element>> callback and then 258 <<aout_link_check_archive_element>> calls 259 <<aout_link_add_symbols>> to actually add the symbols to the 260 linker hash table. 261 262 The ECOFF back end is unusual in that it does not normally 263 call <<_bfd_generic_link_add_archive_symbols>>, because ECOFF 264 archives already contain a hash table of symbols. The ECOFF 265 back end searches the archive itself to avoid the overhead of 266 creating a new hash table. 267 268 INODE 269 Performing the Final Link, , Adding Symbols to the Hash Table, Linker Functions 270 SUBSECTION 271 Performing the final link 272 273 @cindex _bfd_link_final_link in target vector 274 @cindex target vector (_bfd_final_link) 275 When all the input files have been processed, the linker calls 276 the <<_bfd_final_link>> entry point of the output BFD. This 277 routine is responsible for producing the final output file, 278 which has several aspects. It must relocate the contents of 279 the input sections and copy the data into the output sections. 280 It must build an output symbol table including any local 281 symbols from the input files and the global symbols from the 282 hash table. When producing relocatable output, it must 283 modify the input relocs and write them into the output file. 284 There may also be object format dependent work to be done. 285 286 The linker will also call the <<write_object_contents>> entry 287 point when the BFD is closed. The two entry points must work 288 together in order to produce the correct output file. 289 290 The details of how this works are inevitably dependent upon 291 the specific object file format. The a.out 292 <<_bfd_final_link>> routine is <<NAME(aout,final_link)>>. 293 294 @menu 295 @* Information provided by the linker:: 296 @* Relocating the section contents:: 297 @* Writing the symbol table:: 298 @end menu 299 300 INODE 301 Information provided by the linker, Relocating the section contents, Performing the Final Link, Performing the Final Link 302 SUBSUBSECTION 303 Information provided by the linker 304 305 Before the linker calls the <<_bfd_final_link>> entry point, 306 it sets up some data structures for the function to use. 307 308 The <<input_bfds>> field of the <<bfd_link_info>> structure 309 will point to a list of all the input files included in the 310 link. These files are linked through the <<link_next>> field 311 of the <<bfd>> structure. 312 313 Each section in the output file will have a list of 314 <<link_order>> structures attached to the <<map_head.link_order>> 315 field (the <<link_order>> structure is defined in 316 <<bfdlink.h>>). These structures describe how to create the 317 contents of the output section in terms of the contents of 318 various input sections, fill constants, and, eventually, other 319 types of information. They also describe relocs that must be 320 created by the BFD backend, but do not correspond to any input 321 file; this is used to support -Ur, which builds constructors 322 while generating a relocatable object file. 323 324 INODE 325 Relocating the section contents, Writing the symbol table, Information provided by the linker, Performing the Final Link 326 SUBSUBSECTION 327 Relocating the section contents 328 329 The <<_bfd_final_link>> function should look through the 330 <<link_order>> structures attached to each section of the 331 output file. Each <<link_order>> structure should either be 332 handled specially, or it should be passed to the function 333 <<_bfd_default_link_order>> which will do the right thing 334 (<<_bfd_default_link_order>> is defined in <<linker.c>>). 335 336 For efficiency, a <<link_order>> of type 337 <<bfd_indirect_link_order>> whose associated section belongs 338 to a BFD of the same format as the output BFD must be handled 339 specially. This type of <<link_order>> describes part of an 340 output section in terms of a section belonging to one of the 341 input files. The <<_bfd_final_link>> function should read the 342 contents of the section and any associated relocs, apply the 343 relocs to the section contents, and write out the modified 344 section contents. If performing a relocatable link, the 345 relocs themselves must also be modified and written out. 346 347 @findex _bfd_relocate_contents 348 @findex _bfd_final_link_relocate 349 The functions <<_bfd_relocate_contents>> and 350 <<_bfd_final_link_relocate>> provide some general support for 351 performing the actual relocations, notably overflow checking. 352 Their arguments include information about the symbol the 353 relocation is against and a <<reloc_howto_type>> argument 354 which describes the relocation to perform. These functions 355 are defined in <<reloc.c>>. 356 357 The a.out function which handles reading, relocating, and 358 writing section contents is <<aout_link_input_section>>. The 359 actual relocation is done in <<aout_link_input_section_std>> 360 and <<aout_link_input_section_ext>>. 361 362 INODE 363 Writing the symbol table, , Relocating the section contents, Performing the Final Link 364 SUBSUBSECTION 365 Writing the symbol table 366 367 The <<_bfd_final_link>> function must gather all the symbols 368 in the input files and write them out. It must also write out 369 all the symbols in the global hash table. This must be 370 controlled by the <<strip>> and <<discard>> fields of the 371 <<bfd_link_info>> structure. 372 373 The local symbols of the input files will not have been 374 entered into the linker hash table. The <<_bfd_final_link>> 375 routine must consider each input file and include the symbols 376 in the output file. It may be convenient to do this when 377 looking through the <<link_order>> structures, or it may be 378 done by stepping through the <<input_bfds>> list. 379 380 The <<_bfd_final_link>> routine must also traverse the global 381 hash table to gather all the externally visible symbols. It 382 is possible that most of the externally visible symbols may be 383 written out when considering the symbols of each input file, 384 but it is still necessary to traverse the hash table since the 385 linker script may have defined some symbols that are not in 386 any of the input files. 387 388 The <<strip>> field of the <<bfd_link_info>> structure 389 controls which symbols are written out. The possible values 390 are listed in <<bfdlink.h>>. If the value is <<strip_some>>, 391 then the <<keep_hash>> field of the <<bfd_link_info>> 392 structure is a hash table of symbols to keep; each symbol 393 should be looked up in this hash table, and only symbols which 394 are present should be included in the output file. 395 396 If the <<strip>> field of the <<bfd_link_info>> structure 397 permits local symbols to be written out, the <<discard>> field 398 is used to further controls which local symbols are included 399 in the output file. If the value is <<discard_l>>, then all 400 local symbols which begin with a certain prefix are discarded; 401 this is controlled by the <<bfd_is_local_label_name>> entry point. 402 403 The a.out backend handles symbols by calling 404 <<aout_link_write_symbols>> on each input BFD and then 405 traversing the global hash table with the function 406 <<aout_link_write_other_symbol>>. It builds a string table 407 while writing out the symbols, which is written to the output 408 file at the end of <<NAME(aout,final_link)>>. 409 */ 410 411 static bfd_boolean generic_link_add_object_symbols 412 (bfd *, struct bfd_link_info *, bfd_boolean collect); 413 static bfd_boolean generic_link_add_symbols 414 (bfd *, struct bfd_link_info *, bfd_boolean); 415 static bfd_boolean generic_link_check_archive_element_no_collect 416 (bfd *, struct bfd_link_info *, bfd_boolean *); 417 static bfd_boolean generic_link_check_archive_element_collect 418 (bfd *, struct bfd_link_info *, bfd_boolean *); 419 static bfd_boolean generic_link_check_archive_element 420 (bfd *, struct bfd_link_info *, bfd_boolean *, bfd_boolean); 421 static bfd_boolean generic_link_add_symbol_list 422 (bfd *, struct bfd_link_info *, bfd_size_type count, asymbol **, 423 bfd_boolean); 424 static bfd_boolean generic_add_output_symbol 425 (bfd *, size_t *psymalloc, asymbol *); 426 static bfd_boolean default_data_link_order 427 (bfd *, struct bfd_link_info *, asection *, struct bfd_link_order *); 428 static bfd_boolean default_indirect_link_order 429 (bfd *, struct bfd_link_info *, asection *, struct bfd_link_order *, 430 bfd_boolean); 431 432 /* The link hash table structure is defined in bfdlink.h. It provides 433 a base hash table which the backend specific hash tables are built 434 upon. */ 435 436 /* Routine to create an entry in the link hash table. */ 437 438 struct bfd_hash_entry * 439 _bfd_link_hash_newfunc (struct bfd_hash_entry *entry, 440 struct bfd_hash_table *table, 441 const char *string) 442 { 443 /* Allocate the structure if it has not already been allocated by a 444 subclass. */ 445 if (entry == NULL) 446 { 447 entry = (struct bfd_hash_entry *) 448 bfd_hash_allocate (table, sizeof (struct bfd_link_hash_entry)); 449 if (entry == NULL) 450 return entry; 451 } 452 453 /* Call the allocation method of the superclass. */ 454 entry = bfd_hash_newfunc (entry, table, string); 455 if (entry) 456 { 457 struct bfd_link_hash_entry *h = (struct bfd_link_hash_entry *) entry; 458 459 /* Initialize the local fields. */ 460 h->type = bfd_link_hash_new; 461 memset (&h->u.undef.next, 0, 462 (sizeof (struct bfd_link_hash_entry) 463 - offsetof (struct bfd_link_hash_entry, u.undef.next))); 464 } 465 466 return entry; 467 } 468 469 /* Initialize a link hash table. The BFD argument is the one 470 responsible for creating this table. */ 471 472 bfd_boolean 473 _bfd_link_hash_table_init 474 (struct bfd_link_hash_table *table, 475 bfd *abfd ATTRIBUTE_UNUSED, 476 struct bfd_hash_entry *(*newfunc) (struct bfd_hash_entry *, 477 struct bfd_hash_table *, 478 const char *), 479 unsigned int entsize) 480 { 481 table->undefs = NULL; 482 table->undefs_tail = NULL; 483 table->type = bfd_link_generic_hash_table; 484 485 return bfd_hash_table_init (&table->table, newfunc, entsize); 486 } 487 488 /* Look up a symbol in a link hash table. If follow is TRUE, we 489 follow bfd_link_hash_indirect and bfd_link_hash_warning links to 490 the real symbol. */ 491 492 struct bfd_link_hash_entry * 493 bfd_link_hash_lookup (struct bfd_link_hash_table *table, 494 const char *string, 495 bfd_boolean create, 496 bfd_boolean copy, 497 bfd_boolean follow) 498 { 499 struct bfd_link_hash_entry *ret; 500 501 ret = ((struct bfd_link_hash_entry *) 502 bfd_hash_lookup (&table->table, string, create, copy)); 503 504 if (follow && ret != NULL) 505 { 506 while (ret->type == bfd_link_hash_indirect 507 || ret->type == bfd_link_hash_warning) 508 ret = ret->u.i.link; 509 } 510 511 return ret; 512 } 513 514 /* Look up a symbol in the main linker hash table if the symbol might 515 be wrapped. This should only be used for references to an 516 undefined symbol, not for definitions of a symbol. */ 517 518 struct bfd_link_hash_entry * 519 bfd_wrapped_link_hash_lookup (bfd *abfd, 520 struct bfd_link_info *info, 521 const char *string, 522 bfd_boolean create, 523 bfd_boolean copy, 524 bfd_boolean follow) 525 { 526 bfd_size_type amt; 527 528 if (info->wrap_hash != NULL) 529 { 530 const char *l; 531 char prefix = '\0'; 532 533 l = string; 534 if (*l == bfd_get_symbol_leading_char (abfd) || *l == info->wrap_char) 535 { 536 prefix = *l; 537 ++l; 538 } 539 540 #undef WRAP 541 #define WRAP "__wrap_" 542 543 if (bfd_hash_lookup (info->wrap_hash, l, FALSE, FALSE) != NULL) 544 { 545 char *n; 546 struct bfd_link_hash_entry *h; 547 548 /* This symbol is being wrapped. We want to replace all 549 references to SYM with references to __wrap_SYM. */ 550 551 amt = strlen (l) + sizeof WRAP + 1; 552 n = (char *) bfd_malloc (amt); 553 if (n == NULL) 554 return NULL; 555 556 n[0] = prefix; 557 n[1] = '\0'; 558 strcat (n, WRAP); 559 strcat (n, l); 560 h = bfd_link_hash_lookup (info->hash, n, create, TRUE, follow); 561 free (n); 562 return h; 563 } 564 565 #undef WRAP 566 567 #undef REAL 568 #define REAL "__real_" 569 570 if (*l == '_' 571 && CONST_STRNEQ (l, REAL) 572 && bfd_hash_lookup (info->wrap_hash, l + sizeof REAL - 1, 573 FALSE, FALSE) != NULL) 574 { 575 char *n; 576 struct bfd_link_hash_entry *h; 577 578 /* This is a reference to __real_SYM, where SYM is being 579 wrapped. We want to replace all references to __real_SYM 580 with references to SYM. */ 581 582 amt = strlen (l + sizeof REAL - 1) + 2; 583 n = (char *) bfd_malloc (amt); 584 if (n == NULL) 585 return NULL; 586 587 n[0] = prefix; 588 n[1] = '\0'; 589 strcat (n, l + sizeof REAL - 1); 590 h = bfd_link_hash_lookup (info->hash, n, create, TRUE, follow); 591 free (n); 592 return h; 593 } 594 595 #undef REAL 596 } 597 598 return bfd_link_hash_lookup (info->hash, string, create, copy, follow); 599 } 600 601 /* Traverse a generic link hash table. The only reason this is not a 602 macro is to do better type checking. This code presumes that an 603 argument passed as a struct bfd_hash_entry * may be caught as a 604 struct bfd_link_hash_entry * with no explicit cast required on the 605 call. */ 606 607 void 608 bfd_link_hash_traverse 609 (struct bfd_link_hash_table *table, 610 bfd_boolean (*func) (struct bfd_link_hash_entry *, void *), 611 void *info) 612 { 613 bfd_hash_traverse (&table->table, 614 (bfd_boolean (*) (struct bfd_hash_entry *, void *)) func, 615 info); 616 } 617 618 /* Add a symbol to the linker hash table undefs list. */ 619 620 void 621 bfd_link_add_undef (struct bfd_link_hash_table *table, 622 struct bfd_link_hash_entry *h) 623 { 624 BFD_ASSERT (h->u.undef.next == NULL); 625 if (table->undefs_tail != NULL) 626 table->undefs_tail->u.undef.next = h; 627 if (table->undefs == NULL) 628 table->undefs = h; 629 table->undefs_tail = h; 630 } 631 632 /* The undefs list was designed so that in normal use we don't need to 633 remove entries. However, if symbols on the list are changed from 634 bfd_link_hash_undefined to either bfd_link_hash_undefweak or 635 bfd_link_hash_new for some reason, then they must be removed from the 636 list. Failure to do so might result in the linker attempting to add 637 the symbol to the list again at a later stage. */ 638 639 void 640 bfd_link_repair_undef_list (struct bfd_link_hash_table *table) 641 { 642 struct bfd_link_hash_entry **pun; 643 644 pun = &table->undefs; 645 while (*pun != NULL) 646 { 647 struct bfd_link_hash_entry *h = *pun; 648 649 if (h->type == bfd_link_hash_new 650 || h->type == bfd_link_hash_undefweak) 651 { 652 *pun = h->u.undef.next; 653 h->u.undef.next = NULL; 654 if (h == table->undefs_tail) 655 { 656 if (pun == &table->undefs) 657 table->undefs_tail = NULL; 658 else 659 /* pun points at an u.undef.next field. Go back to 660 the start of the link_hash_entry. */ 661 table->undefs_tail = (struct bfd_link_hash_entry *) 662 ((char *) pun - ((char *) &h->u.undef.next - (char *) h)); 663 break; 664 } 665 } 666 else 667 pun = &h->u.undef.next; 668 } 669 } 670 671 /* Routine to create an entry in a generic link hash table. */ 672 673 struct bfd_hash_entry * 674 _bfd_generic_link_hash_newfunc (struct bfd_hash_entry *entry, 675 struct bfd_hash_table *table, 676 const char *string) 677 { 678 /* Allocate the structure if it has not already been allocated by a 679 subclass. */ 680 if (entry == NULL) 681 { 682 entry = (struct bfd_hash_entry *) 683 bfd_hash_allocate (table, sizeof (struct generic_link_hash_entry)); 684 if (entry == NULL) 685 return entry; 686 } 687 688 /* Call the allocation method of the superclass. */ 689 entry = _bfd_link_hash_newfunc (entry, table, string); 690 if (entry) 691 { 692 struct generic_link_hash_entry *ret; 693 694 /* Set local fields. */ 695 ret = (struct generic_link_hash_entry *) entry; 696 ret->written = FALSE; 697 ret->sym = NULL; 698 } 699 700 return entry; 701 } 702 703 /* Create a generic link hash table. */ 704 705 struct bfd_link_hash_table * 706 _bfd_generic_link_hash_table_create (bfd *abfd) 707 { 708 struct generic_link_hash_table *ret; 709 bfd_size_type amt = sizeof (struct generic_link_hash_table); 710 711 ret = (struct generic_link_hash_table *) bfd_malloc (amt); 712 if (ret == NULL) 713 return NULL; 714 if (! _bfd_link_hash_table_init (&ret->root, abfd, 715 _bfd_generic_link_hash_newfunc, 716 sizeof (struct generic_link_hash_entry))) 717 { 718 free (ret); 719 return NULL; 720 } 721 return &ret->root; 722 } 723 724 void 725 _bfd_generic_link_hash_table_free (struct bfd_link_hash_table *hash) 726 { 727 struct generic_link_hash_table *ret 728 = (struct generic_link_hash_table *) hash; 729 730 bfd_hash_table_free (&ret->root.table); 731 free (ret); 732 } 733 734 /* Grab the symbols for an object file when doing a generic link. We 735 store the symbols in the outsymbols field. We need to keep them 736 around for the entire link to ensure that we only read them once. 737 If we read them multiple times, we might wind up with relocs and 738 the hash table pointing to different instances of the symbol 739 structure. */ 740 741 bfd_boolean 742 bfd_generic_link_read_symbols (bfd *abfd) 743 { 744 if (bfd_get_outsymbols (abfd) == NULL) 745 { 746 long symsize; 747 long symcount; 748 749 symsize = bfd_get_symtab_upper_bound (abfd); 750 if (symsize < 0) 751 return FALSE; 752 bfd_get_outsymbols (abfd) = (struct bfd_symbol **) bfd_alloc (abfd, 753 symsize); 754 if (bfd_get_outsymbols (abfd) == NULL && symsize != 0) 755 return FALSE; 756 symcount = bfd_canonicalize_symtab (abfd, bfd_get_outsymbols (abfd)); 757 if (symcount < 0) 758 return FALSE; 759 bfd_get_symcount (abfd) = symcount; 760 } 761 762 return TRUE; 763 } 764 765 /* Generic function to add symbols to from an object file to the 766 global hash table. This version does not automatically collect 767 constructors by name. */ 768 769 bfd_boolean 770 _bfd_generic_link_add_symbols (bfd *abfd, struct bfd_link_info *info) 771 { 772 return generic_link_add_symbols (abfd, info, FALSE); 773 } 774 775 /* Generic function to add symbols from an object file to the global 776 hash table. This version automatically collects constructors by 777 name, as the collect2 program does. It should be used for any 778 target which does not provide some other mechanism for setting up 779 constructors and destructors; these are approximately those targets 780 for which gcc uses collect2 and do not support stabs. */ 781 782 bfd_boolean 783 _bfd_generic_link_add_symbols_collect (bfd *abfd, struct bfd_link_info *info) 784 { 785 return generic_link_add_symbols (abfd, info, TRUE); 786 } 787 788 /* Indicate that we are only retrieving symbol values from this 789 section. We want the symbols to act as though the values in the 790 file are absolute. */ 791 792 void 793 _bfd_generic_link_just_syms (asection *sec, 794 struct bfd_link_info *info ATTRIBUTE_UNUSED) 795 { 796 sec->output_section = bfd_abs_section_ptr; 797 sec->output_offset = sec->vma; 798 } 799 800 /* Add symbols from an object file to the global hash table. */ 801 802 static bfd_boolean 803 generic_link_add_symbols (bfd *abfd, 804 struct bfd_link_info *info, 805 bfd_boolean collect) 806 { 807 bfd_boolean ret; 808 809 switch (bfd_get_format (abfd)) 810 { 811 case bfd_object: 812 ret = generic_link_add_object_symbols (abfd, info, collect); 813 break; 814 case bfd_archive: 815 ret = (_bfd_generic_link_add_archive_symbols 816 (abfd, info, 817 (collect 818 ? generic_link_check_archive_element_collect 819 : generic_link_check_archive_element_no_collect))); 820 break; 821 default: 822 bfd_set_error (bfd_error_wrong_format); 823 ret = FALSE; 824 } 825 826 return ret; 827 } 828 829 /* Add symbols from an object file to the global hash table. */ 830 831 static bfd_boolean 832 generic_link_add_object_symbols (bfd *abfd, 833 struct bfd_link_info *info, 834 bfd_boolean collect) 835 { 836 bfd_size_type symcount; 837 struct bfd_symbol **outsyms; 838 839 if (!bfd_generic_link_read_symbols (abfd)) 840 return FALSE; 841 symcount = _bfd_generic_link_get_symcount (abfd); 842 outsyms = _bfd_generic_link_get_symbols (abfd); 843 return generic_link_add_symbol_list (abfd, info, symcount, outsyms, collect); 844 } 845 846 /* We build a hash table of all symbols defined in an archive. */ 847 848 /* An archive symbol may be defined by multiple archive elements. 849 This linked list is used to hold the elements. */ 850 851 struct archive_list 852 { 853 struct archive_list *next; 854 unsigned int indx; 855 }; 856 857 /* An entry in an archive hash table. */ 858 859 struct archive_hash_entry 860 { 861 struct bfd_hash_entry root; 862 /* Where the symbol is defined. */ 863 struct archive_list *defs; 864 }; 865 866 /* An archive hash table itself. */ 867 868 struct archive_hash_table 869 { 870 struct bfd_hash_table table; 871 }; 872 873 /* Create a new entry for an archive hash table. */ 874 875 static struct bfd_hash_entry * 876 archive_hash_newfunc (struct bfd_hash_entry *entry, 877 struct bfd_hash_table *table, 878 const char *string) 879 { 880 struct archive_hash_entry *ret = (struct archive_hash_entry *) entry; 881 882 /* Allocate the structure if it has not already been allocated by a 883 subclass. */ 884 if (ret == NULL) 885 ret = (struct archive_hash_entry *) 886 bfd_hash_allocate (table, sizeof (struct archive_hash_entry)); 887 if (ret == NULL) 888 return NULL; 889 890 /* Call the allocation method of the superclass. */ 891 ret = ((struct archive_hash_entry *) 892 bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string)); 893 894 if (ret) 895 { 896 /* Initialize the local fields. */ 897 ret->defs = NULL; 898 } 899 900 return &ret->root; 901 } 902 903 /* Initialize an archive hash table. */ 904 905 static bfd_boolean 906 archive_hash_table_init 907 (struct archive_hash_table *table, 908 struct bfd_hash_entry *(*newfunc) (struct bfd_hash_entry *, 909 struct bfd_hash_table *, 910 const char *), 911 unsigned int entsize) 912 { 913 return bfd_hash_table_init (&table->table, newfunc, entsize); 914 } 915 916 /* Look up an entry in an archive hash table. */ 917 918 #define archive_hash_lookup(t, string, create, copy) \ 919 ((struct archive_hash_entry *) \ 920 bfd_hash_lookup (&(t)->table, (string), (create), (copy))) 921 922 /* Allocate space in an archive hash table. */ 923 924 #define archive_hash_allocate(t, size) bfd_hash_allocate (&(t)->table, (size)) 925 926 /* Free an archive hash table. */ 927 928 #define archive_hash_table_free(t) bfd_hash_table_free (&(t)->table) 929 930 /* Generic function to add symbols from an archive file to the global 931 hash file. This function presumes that the archive symbol table 932 has already been read in (this is normally done by the 933 bfd_check_format entry point). It looks through the undefined and 934 common symbols and searches the archive symbol table for them. If 935 it finds an entry, it includes the associated object file in the 936 link. 937 938 The old linker looked through the archive symbol table for 939 undefined symbols. We do it the other way around, looking through 940 undefined symbols for symbols defined in the archive. The 941 advantage of the newer scheme is that we only have to look through 942 the list of undefined symbols once, whereas the old method had to 943 re-search the symbol table each time a new object file was added. 944 945 The CHECKFN argument is used to see if an object file should be 946 included. CHECKFN should set *PNEEDED to TRUE if the object file 947 should be included, and must also call the bfd_link_info 948 add_archive_element callback function and handle adding the symbols 949 to the global hash table. CHECKFN should only return FALSE if some 950 sort of error occurs. 951 952 For some formats, such as a.out, it is possible to look through an 953 object file but not actually include it in the link. The 954 archive_pass field in a BFD is used to avoid checking the symbols 955 of an object files too many times. When an object is included in 956 the link, archive_pass is set to -1. If an object is scanned but 957 not included, archive_pass is set to the pass number. The pass 958 number is incremented each time a new object file is included. The 959 pass number is used because when a new object file is included it 960 may create new undefined symbols which cause a previously examined 961 object file to be included. */ 962 963 bfd_boolean 964 _bfd_generic_link_add_archive_symbols 965 (bfd *abfd, 966 struct bfd_link_info *info, 967 bfd_boolean (*checkfn) (bfd *, struct bfd_link_info *, bfd_boolean *)) 968 { 969 carsym *arsyms; 970 carsym *arsym_end; 971 register carsym *arsym; 972 int pass; 973 struct archive_hash_table arsym_hash; 974 unsigned int indx; 975 struct bfd_link_hash_entry **pundef; 976 977 if (! bfd_has_map (abfd)) 978 { 979 /* An empty archive is a special case. */ 980 if (bfd_openr_next_archived_file (abfd, NULL) == NULL) 981 return TRUE; 982 bfd_set_error (bfd_error_no_armap); 983 return FALSE; 984 } 985 986 arsyms = bfd_ardata (abfd)->symdefs; 987 arsym_end = arsyms + bfd_ardata (abfd)->symdef_count; 988 989 /* In order to quickly determine whether an symbol is defined in 990 this archive, we build a hash table of the symbols. */ 991 if (! archive_hash_table_init (&arsym_hash, archive_hash_newfunc, 992 sizeof (struct archive_hash_entry))) 993 return FALSE; 994 for (arsym = arsyms, indx = 0; arsym < arsym_end; arsym++, indx++) 995 { 996 struct archive_hash_entry *arh; 997 struct archive_list *l, **pp; 998 999 arh = archive_hash_lookup (&arsym_hash, arsym->name, TRUE, FALSE); 1000 if (arh == NULL) 1001 goto error_return; 1002 l = ((struct archive_list *) 1003 archive_hash_allocate (&arsym_hash, sizeof (struct archive_list))); 1004 if (l == NULL) 1005 goto error_return; 1006 l->indx = indx; 1007 for (pp = &arh->defs; *pp != NULL; pp = &(*pp)->next) 1008 ; 1009 *pp = l; 1010 l->next = NULL; 1011 } 1012 1013 /* The archive_pass field in the archive itself is used to 1014 initialize PASS, sine we may search the same archive multiple 1015 times. */ 1016 pass = abfd->archive_pass + 1; 1017 1018 /* New undefined symbols are added to the end of the list, so we 1019 only need to look through it once. */ 1020 pundef = &info->hash->undefs; 1021 while (*pundef != NULL) 1022 { 1023 struct bfd_link_hash_entry *h; 1024 struct archive_hash_entry *arh; 1025 struct archive_list *l; 1026 1027 h = *pundef; 1028 1029 /* When a symbol is defined, it is not necessarily removed from 1030 the list. */ 1031 if (h->type != bfd_link_hash_undefined 1032 && h->type != bfd_link_hash_common) 1033 { 1034 /* Remove this entry from the list, for general cleanliness 1035 and because we are going to look through the list again 1036 if we search any more libraries. We can't remove the 1037 entry if it is the tail, because that would lose any 1038 entries we add to the list later on (it would also cause 1039 us to lose track of whether the symbol has been 1040 referenced). */ 1041 if (*pundef != info->hash->undefs_tail) 1042 *pundef = (*pundef)->u.undef.next; 1043 else 1044 pundef = &(*pundef)->u.undef.next; 1045 continue; 1046 } 1047 1048 /* Look for this symbol in the archive symbol map. */ 1049 arh = archive_hash_lookup (&arsym_hash, h->root.string, FALSE, FALSE); 1050 if (arh == NULL) 1051 { 1052 /* If we haven't found the exact symbol we're looking for, 1053 let's look for its import thunk */ 1054 if (info->pei386_auto_import) 1055 { 1056 bfd_size_type amt = strlen (h->root.string) + 10; 1057 char *buf = (char *) bfd_malloc (amt); 1058 if (buf == NULL) 1059 return FALSE; 1060 1061 sprintf (buf, "__imp_%s", h->root.string); 1062 arh = archive_hash_lookup (&arsym_hash, buf, FALSE, FALSE); 1063 free(buf); 1064 } 1065 if (arh == NULL) 1066 { 1067 pundef = &(*pundef)->u.undef.next; 1068 continue; 1069 } 1070 } 1071 /* Look at all the objects which define this symbol. */ 1072 for (l = arh->defs; l != NULL; l = l->next) 1073 { 1074 bfd *element; 1075 bfd_boolean needed; 1076 1077 /* If the symbol has gotten defined along the way, quit. */ 1078 if (h->type != bfd_link_hash_undefined 1079 && h->type != bfd_link_hash_common) 1080 break; 1081 1082 element = bfd_get_elt_at_index (abfd, l->indx); 1083 if (element == NULL) 1084 goto error_return; 1085 1086 /* If we've already included this element, or if we've 1087 already checked it on this pass, continue. */ 1088 if (element->archive_pass == -1 1089 || element->archive_pass == pass) 1090 continue; 1091 1092 /* If we can't figure this element out, just ignore it. */ 1093 if (! bfd_check_format (element, bfd_object)) 1094 { 1095 element->archive_pass = -1; 1096 continue; 1097 } 1098 1099 /* CHECKFN will see if this element should be included, and 1100 go ahead and include it if appropriate. */ 1101 if (! (*checkfn) (element, info, &needed)) 1102 goto error_return; 1103 1104 if (! needed) 1105 element->archive_pass = pass; 1106 else 1107 { 1108 element->archive_pass = -1; 1109 1110 /* Increment the pass count to show that we may need to 1111 recheck object files which were already checked. */ 1112 ++pass; 1113 } 1114 } 1115 1116 pundef = &(*pundef)->u.undef.next; 1117 } 1118 1119 archive_hash_table_free (&arsym_hash); 1120 1121 /* Save PASS in case we are called again. */ 1122 abfd->archive_pass = pass; 1123 1124 return TRUE; 1125 1126 error_return: 1127 archive_hash_table_free (&arsym_hash); 1128 return FALSE; 1129 } 1130 1131 /* See if we should include an archive element. This version is used 1132 when we do not want to automatically collect constructors based on 1133 the symbol name, presumably because we have some other mechanism 1134 for finding them. */ 1135 1136 static bfd_boolean 1137 generic_link_check_archive_element_no_collect ( 1138 bfd *abfd, 1139 struct bfd_link_info *info, 1140 bfd_boolean *pneeded) 1141 { 1142 return generic_link_check_archive_element (abfd, info, pneeded, FALSE); 1143 } 1144 1145 /* See if we should include an archive element. This version is used 1146 when we want to automatically collect constructors based on the 1147 symbol name, as collect2 does. */ 1148 1149 static bfd_boolean 1150 generic_link_check_archive_element_collect (bfd *abfd, 1151 struct bfd_link_info *info, 1152 bfd_boolean *pneeded) 1153 { 1154 return generic_link_check_archive_element (abfd, info, pneeded, TRUE); 1155 } 1156 1157 /* See if we should include an archive element. Optionally collect 1158 constructors. */ 1159 1160 static bfd_boolean 1161 generic_link_check_archive_element (bfd *abfd, 1162 struct bfd_link_info *info, 1163 bfd_boolean *pneeded, 1164 bfd_boolean collect) 1165 { 1166 asymbol **pp, **ppend; 1167 1168 *pneeded = FALSE; 1169 1170 if (!bfd_generic_link_read_symbols (abfd)) 1171 return FALSE; 1172 1173 pp = _bfd_generic_link_get_symbols (abfd); 1174 ppend = pp + _bfd_generic_link_get_symcount (abfd); 1175 for (; pp < ppend; pp++) 1176 { 1177 asymbol *p; 1178 struct bfd_link_hash_entry *h; 1179 1180 p = *pp; 1181 1182 /* We are only interested in globally visible symbols. */ 1183 if (! bfd_is_com_section (p->section) 1184 && (p->flags & (BSF_GLOBAL | BSF_INDIRECT | BSF_WEAK)) == 0) 1185 continue; 1186 1187 /* We are only interested if we know something about this 1188 symbol, and it is undefined or common. An undefined weak 1189 symbol (type bfd_link_hash_undefweak) is not considered to be 1190 a reference when pulling files out of an archive. See the 1191 SVR4 ABI, p. 4-27. */ 1192 h = bfd_link_hash_lookup (info->hash, bfd_asymbol_name (p), FALSE, 1193 FALSE, TRUE); 1194 if (h == NULL 1195 || (h->type != bfd_link_hash_undefined 1196 && h->type != bfd_link_hash_common)) 1197 continue; 1198 1199 /* P is a symbol we are looking for. */ 1200 1201 if (! bfd_is_com_section (p->section)) 1202 { 1203 bfd_size_type symcount; 1204 asymbol **symbols; 1205 1206 /* This object file defines this symbol, so pull it in. */ 1207 if (! (*info->callbacks->add_archive_element) (info, abfd, 1208 bfd_asymbol_name (p))) 1209 return FALSE; 1210 symcount = _bfd_generic_link_get_symcount (abfd); 1211 symbols = _bfd_generic_link_get_symbols (abfd); 1212 if (! generic_link_add_symbol_list (abfd, info, symcount, 1213 symbols, collect)) 1214 return FALSE; 1215 *pneeded = TRUE; 1216 return TRUE; 1217 } 1218 1219 /* P is a common symbol. */ 1220 1221 if (h->type == bfd_link_hash_undefined) 1222 { 1223 bfd *symbfd; 1224 bfd_vma size; 1225 unsigned int power; 1226 1227 symbfd = h->u.undef.abfd; 1228 if (symbfd == NULL) 1229 { 1230 /* This symbol was created as undefined from outside 1231 BFD. We assume that we should link in the object 1232 file. This is for the -u option in the linker. */ 1233 if (! (*info->callbacks->add_archive_element) 1234 (info, abfd, bfd_asymbol_name (p))) 1235 return FALSE; 1236 *pneeded = TRUE; 1237 return TRUE; 1238 } 1239 1240 /* Turn the symbol into a common symbol but do not link in 1241 the object file. This is how a.out works. Object 1242 formats that require different semantics must implement 1243 this function differently. This symbol is already on the 1244 undefs list. We add the section to a common section 1245 attached to symbfd to ensure that it is in a BFD which 1246 will be linked in. */ 1247 h->type = bfd_link_hash_common; 1248 h->u.c.p = (struct bfd_link_hash_common_entry *) 1249 bfd_hash_allocate (&info->hash->table, 1250 sizeof (struct bfd_link_hash_common_entry)); 1251 if (h->u.c.p == NULL) 1252 return FALSE; 1253 1254 size = bfd_asymbol_value (p); 1255 h->u.c.size = size; 1256 1257 power = bfd_log2 (size); 1258 if (power > 4) 1259 power = 4; 1260 h->u.c.p->alignment_power = power; 1261 1262 if (p->section == bfd_com_section_ptr) 1263 h->u.c.p->section = bfd_make_section_old_way (symbfd, "COMMON"); 1264 else 1265 h->u.c.p->section = bfd_make_section_old_way (symbfd, 1266 p->section->name); 1267 h->u.c.p->section->flags = SEC_ALLOC; 1268 } 1269 else 1270 { 1271 /* Adjust the size of the common symbol if necessary. This 1272 is how a.out works. Object formats that require 1273 different semantics must implement this function 1274 differently. */ 1275 if (bfd_asymbol_value (p) > h->u.c.size) 1276 h->u.c.size = bfd_asymbol_value (p); 1277 } 1278 } 1279 1280 /* This archive element is not needed. */ 1281 return TRUE; 1282 } 1283 1284 /* Add the symbols from an object file to the global hash table. ABFD 1285 is the object file. INFO is the linker information. SYMBOL_COUNT 1286 is the number of symbols. SYMBOLS is the list of symbols. COLLECT 1287 is TRUE if constructors should be automatically collected by name 1288 as is done by collect2. */ 1289 1290 static bfd_boolean 1291 generic_link_add_symbol_list (bfd *abfd, 1292 struct bfd_link_info *info, 1293 bfd_size_type symbol_count, 1294 asymbol **symbols, 1295 bfd_boolean collect) 1296 { 1297 asymbol **pp, **ppend; 1298 1299 pp = symbols; 1300 ppend = symbols + symbol_count; 1301 for (; pp < ppend; pp++) 1302 { 1303 asymbol *p; 1304 1305 p = *pp; 1306 1307 if ((p->flags & (BSF_INDIRECT 1308 | BSF_WARNING 1309 | BSF_GLOBAL 1310 | BSF_CONSTRUCTOR 1311 | BSF_WEAK)) != 0 1312 || bfd_is_und_section (bfd_get_section (p)) 1313 || bfd_is_com_section (bfd_get_section (p)) 1314 || bfd_is_ind_section (bfd_get_section (p))) 1315 { 1316 const char *name; 1317 const char *string; 1318 struct generic_link_hash_entry *h; 1319 struct bfd_link_hash_entry *bh; 1320 1321 string = name = bfd_asymbol_name (p); 1322 if (((p->flags & BSF_INDIRECT) != 0 1323 || bfd_is_ind_section (p->section)) 1324 && pp + 1 < ppend) 1325 { 1326 pp++; 1327 string = bfd_asymbol_name (*pp); 1328 } 1329 else if ((p->flags & BSF_WARNING) != 0 1330 && pp + 1 < ppend) 1331 { 1332 /* The name of P is actually the warning string, and the 1333 next symbol is the one to warn about. */ 1334 pp++; 1335 name = bfd_asymbol_name (*pp); 1336 } 1337 1338 bh = NULL; 1339 if (! (_bfd_generic_link_add_one_symbol 1340 (info, abfd, name, p->flags, bfd_get_section (p), 1341 p->value, string, FALSE, collect, &bh))) 1342 return FALSE; 1343 h = (struct generic_link_hash_entry *) bh; 1344 1345 /* If this is a constructor symbol, and the linker didn't do 1346 anything with it, then we want to just pass the symbol 1347 through to the output file. This will happen when 1348 linking with -r. */ 1349 if ((p->flags & BSF_CONSTRUCTOR) != 0 1350 && (h == NULL || h->root.type == bfd_link_hash_new)) 1351 { 1352 p->udata.p = NULL; 1353 continue; 1354 } 1355 1356 /* Save the BFD symbol so that we don't lose any backend 1357 specific information that may be attached to it. We only 1358 want this one if it gives more information than the 1359 existing one; we don't want to replace a defined symbol 1360 with an undefined one. This routine may be called with a 1361 hash table other than the generic hash table, so we only 1362 do this if we are certain that the hash table is a 1363 generic one. */ 1364 if (info->output_bfd->xvec == abfd->xvec) 1365 { 1366 if (h->sym == NULL 1367 || (! bfd_is_und_section (bfd_get_section (p)) 1368 && (! bfd_is_com_section (bfd_get_section (p)) 1369 || bfd_is_und_section (bfd_get_section (h->sym))))) 1370 { 1371 h->sym = p; 1372 /* BSF_OLD_COMMON is a hack to support COFF reloc 1373 reading, and it should go away when the COFF 1374 linker is switched to the new version. */ 1375 if (bfd_is_com_section (bfd_get_section (p))) 1376 p->flags |= BSF_OLD_COMMON; 1377 } 1378 } 1379 1380 /* Store a back pointer from the symbol to the hash 1381 table entry for the benefit of relaxation code until 1382 it gets rewritten to not use asymbol structures. 1383 Setting this is also used to check whether these 1384 symbols were set up by the generic linker. */ 1385 p->udata.p = h; 1386 } 1387 } 1388 1389 return TRUE; 1390 } 1391 1392 /* We use a state table to deal with adding symbols from an object 1393 file. The first index into the state table describes the symbol 1394 from the object file. The second index into the state table is the 1395 type of the symbol in the hash table. */ 1396 1397 /* The symbol from the object file is turned into one of these row 1398 values. */ 1399 1400 enum link_row 1401 { 1402 UNDEF_ROW, /* Undefined. */ 1403 UNDEFW_ROW, /* Weak undefined. */ 1404 DEF_ROW, /* Defined. */ 1405 DEFW_ROW, /* Weak defined. */ 1406 COMMON_ROW, /* Common. */ 1407 INDR_ROW, /* Indirect. */ 1408 WARN_ROW, /* Warning. */ 1409 SET_ROW /* Member of set. */ 1410 }; 1411 1412 /* apparently needed for Hitachi 3050R(HI-UX/WE2)? */ 1413 #undef FAIL 1414 1415 /* The actions to take in the state table. */ 1416 1417 enum link_action 1418 { 1419 FAIL, /* Abort. */ 1420 UND, /* Mark symbol undefined. */ 1421 WEAK, /* Mark symbol weak undefined. */ 1422 DEF, /* Mark symbol defined. */ 1423 DEFW, /* Mark symbol weak defined. */ 1424 COM, /* Mark symbol common. */ 1425 REF, /* Mark defined symbol referenced. */ 1426 CREF, /* Possibly warn about common reference to defined symbol. */ 1427 CDEF, /* Define existing common symbol. */ 1428 NOACT, /* No action. */ 1429 BIG, /* Mark symbol common using largest size. */ 1430 MDEF, /* Multiple definition error. */ 1431 MIND, /* Multiple indirect symbols. */ 1432 IND, /* Make indirect symbol. */ 1433 CIND, /* Make indirect symbol from existing common symbol. */ 1434 SET, /* Add value to set. */ 1435 MWARN, /* Make warning symbol. */ 1436 WARN, /* Issue warning. */ 1437 CWARN, /* Warn if referenced, else MWARN. */ 1438 CYCLE, /* Repeat with symbol pointed to. */ 1439 REFC, /* Mark indirect symbol referenced and then CYCLE. */ 1440 WARNC /* Issue warning and then CYCLE. */ 1441 }; 1442 1443 /* The state table itself. The first index is a link_row and the 1444 second index is a bfd_link_hash_type. */ 1445 1446 static const enum link_action link_action[8][8] = 1447 { 1448 /* current\prev new undef undefw def defw com indr warn */ 1449 /* UNDEF_ROW */ {UND, NOACT, UND, REF, REF, NOACT, REFC, WARNC }, 1450 /* UNDEFW_ROW */ {WEAK, NOACT, NOACT, REF, REF, NOACT, REFC, WARNC }, 1451 /* DEF_ROW */ {DEF, DEF, DEF, MDEF, DEF, CDEF, MDEF, CYCLE }, 1452 /* DEFW_ROW */ {DEFW, DEFW, DEFW, NOACT, NOACT, NOACT, NOACT, CYCLE }, 1453 /* COMMON_ROW */ {COM, COM, COM, CREF, COM, BIG, REFC, WARNC }, 1454 /* INDR_ROW */ {IND, IND, IND, MDEF, IND, CIND, MIND, CYCLE }, 1455 /* WARN_ROW */ {MWARN, WARN, WARN, CWARN, CWARN, WARN, CWARN, NOACT }, 1456 /* SET_ROW */ {SET, SET, SET, SET, SET, SET, CYCLE, CYCLE } 1457 }; 1458 1459 /* Most of the entries in the LINK_ACTION table are straightforward, 1460 but a few are somewhat subtle. 1461 1462 A reference to an indirect symbol (UNDEF_ROW/indr or 1463 UNDEFW_ROW/indr) is counted as a reference both to the indirect 1464 symbol and to the symbol the indirect symbol points to. 1465 1466 A reference to a warning symbol (UNDEF_ROW/warn or UNDEFW_ROW/warn) 1467 causes the warning to be issued. 1468 1469 A common definition of an indirect symbol (COMMON_ROW/indr) is 1470 treated as a multiple definition error. Likewise for an indirect 1471 definition of a common symbol (INDR_ROW/com). 1472 1473 An indirect definition of a warning (INDR_ROW/warn) does not cause 1474 the warning to be issued. 1475 1476 If a warning is created for an indirect symbol (WARN_ROW/indr) no 1477 warning is created for the symbol the indirect symbol points to. 1478 1479 Adding an entry to a set does not count as a reference to a set, 1480 and no warning is issued (SET_ROW/warn). */ 1481 1482 /* Return the BFD in which a hash entry has been defined, if known. */ 1483 1484 static bfd * 1485 hash_entry_bfd (struct bfd_link_hash_entry *h) 1486 { 1487 while (h->type == bfd_link_hash_warning) 1488 h = h->u.i.link; 1489 switch (h->type) 1490 { 1491 default: 1492 return NULL; 1493 case bfd_link_hash_undefined: 1494 case bfd_link_hash_undefweak: 1495 return h->u.undef.abfd; 1496 case bfd_link_hash_defined: 1497 case bfd_link_hash_defweak: 1498 return h->u.def.section->owner; 1499 case bfd_link_hash_common: 1500 return h->u.c.p->section->owner; 1501 } 1502 /*NOTREACHED*/ 1503 } 1504 1505 /* Add a symbol to the global hash table. 1506 ABFD is the BFD the symbol comes from. 1507 NAME is the name of the symbol. 1508 FLAGS is the BSF_* bits associated with the symbol. 1509 SECTION is the section in which the symbol is defined; this may be 1510 bfd_und_section_ptr or bfd_com_section_ptr. 1511 VALUE is the value of the symbol, relative to the section. 1512 STRING is used for either an indirect symbol, in which case it is 1513 the name of the symbol to indirect to, or a warning symbol, in 1514 which case it is the warning string. 1515 COPY is TRUE if NAME or STRING must be copied into locally 1516 allocated memory if they need to be saved. 1517 COLLECT is TRUE if we should automatically collect gcc constructor 1518 or destructor names as collect2 does. 1519 HASHP, if not NULL, is a place to store the created hash table 1520 entry; if *HASHP is not NULL, the caller has already looked up 1521 the hash table entry, and stored it in *HASHP. */ 1522 1523 bfd_boolean 1524 _bfd_generic_link_add_one_symbol (struct bfd_link_info *info, 1525 bfd *abfd, 1526 const char *name, 1527 flagword flags, 1528 asection *section, 1529 bfd_vma value, 1530 const char *string, 1531 bfd_boolean copy, 1532 bfd_boolean collect, 1533 struct bfd_link_hash_entry **hashp) 1534 { 1535 enum link_row row; 1536 struct bfd_link_hash_entry *h; 1537 bfd_boolean cycle; 1538 1539 if (bfd_is_ind_section (section) 1540 || (flags & BSF_INDIRECT) != 0) 1541 row = INDR_ROW; 1542 else if ((flags & BSF_WARNING) != 0) 1543 row = WARN_ROW; 1544 else if ((flags & BSF_CONSTRUCTOR) != 0) 1545 row = SET_ROW; 1546 else if (bfd_is_und_section (section)) 1547 { 1548 if ((flags & BSF_WEAK) != 0) 1549 row = UNDEFW_ROW; 1550 else 1551 row = UNDEF_ROW; 1552 } 1553 else if ((flags & BSF_WEAK) != 0) 1554 row = DEFW_ROW; 1555 else if (bfd_is_com_section (section)) 1556 row = COMMON_ROW; 1557 else 1558 row = DEF_ROW; 1559 1560 if (hashp != NULL && *hashp != NULL) 1561 h = *hashp; 1562 else 1563 { 1564 if (row == UNDEF_ROW || row == UNDEFW_ROW) 1565 h = bfd_wrapped_link_hash_lookup (abfd, info, name, TRUE, copy, FALSE); 1566 else 1567 h = bfd_link_hash_lookup (info->hash, name, TRUE, copy, FALSE); 1568 if (h == NULL) 1569 { 1570 if (hashp != NULL) 1571 *hashp = NULL; 1572 return FALSE; 1573 } 1574 } 1575 1576 if (info->notice_all 1577 || (info->notice_hash != NULL 1578 && bfd_hash_lookup (info->notice_hash, name, FALSE, FALSE) != NULL)) 1579 { 1580 if (! (*info->callbacks->notice) (info, h->root.string, abfd, section, 1581 value)) 1582 return FALSE; 1583 } 1584 1585 if (hashp != NULL) 1586 *hashp = h; 1587 1588 do 1589 { 1590 enum link_action action; 1591 1592 cycle = FALSE; 1593 action = link_action[(int) row][(int) h->type]; 1594 switch (action) 1595 { 1596 case FAIL: 1597 abort (); 1598 1599 case NOACT: 1600 /* Do nothing. */ 1601 break; 1602 1603 case UND: 1604 /* Make a new undefined symbol. */ 1605 h->type = bfd_link_hash_undefined; 1606 h->u.undef.abfd = abfd; 1607 bfd_link_add_undef (info->hash, h); 1608 break; 1609 1610 case WEAK: 1611 /* Make a new weak undefined symbol. */ 1612 h->type = bfd_link_hash_undefweak; 1613 h->u.undef.abfd = abfd; 1614 h->u.undef.weak = abfd; 1615 break; 1616 1617 case CDEF: 1618 /* We have found a definition for a symbol which was 1619 previously common. */ 1620 BFD_ASSERT (h->type == bfd_link_hash_common); 1621 if (! ((*info->callbacks->multiple_common) 1622 (info, h->root.string, 1623 h->u.c.p->section->owner, bfd_link_hash_common, h->u.c.size, 1624 abfd, bfd_link_hash_defined, 0))) 1625 return FALSE; 1626 /* Fall through. */ 1627 case DEF: 1628 case DEFW: 1629 { 1630 enum bfd_link_hash_type oldtype; 1631 1632 /* Define a symbol. */ 1633 oldtype = h->type; 1634 if (action == DEFW) 1635 h->type = bfd_link_hash_defweak; 1636 else 1637 h->type = bfd_link_hash_defined; 1638 h->u.def.section = section; 1639 h->u.def.value = value; 1640 1641 /* If we have been asked to, we act like collect2 and 1642 identify all functions that might be global 1643 constructors and destructors and pass them up in a 1644 callback. We only do this for certain object file 1645 types, since many object file types can handle this 1646 automatically. */ 1647 if (collect && name[0] == '_') 1648 { 1649 const char *s; 1650 1651 /* A constructor or destructor name starts like this: 1652 _+GLOBAL_[_.$][ID][_.$] where the first [_.$] and 1653 the second are the same character (we accept any 1654 character there, in case a new object file format 1655 comes along with even worse naming restrictions). */ 1656 1657 #define CONS_PREFIX "GLOBAL_" 1658 #define CONS_PREFIX_LEN (sizeof CONS_PREFIX - 1) 1659 1660 s = name + 1; 1661 while (*s == '_') 1662 ++s; 1663 if (s[0] == 'G' && CONST_STRNEQ (s, CONS_PREFIX)) 1664 { 1665 char c; 1666 1667 c = s[CONS_PREFIX_LEN + 1]; 1668 if ((c == 'I' || c == 'D') 1669 && s[CONS_PREFIX_LEN] == s[CONS_PREFIX_LEN + 2]) 1670 { 1671 /* If this is a definition of a symbol which 1672 was previously weakly defined, we are in 1673 trouble. We have already added a 1674 constructor entry for the weak defined 1675 symbol, and now we are trying to add one 1676 for the new symbol. Fortunately, this case 1677 should never arise in practice. */ 1678 if (oldtype == bfd_link_hash_defweak) 1679 abort (); 1680 1681 if (! ((*info->callbacks->constructor) 1682 (info, c == 'I', 1683 h->root.string, abfd, section, value))) 1684 return FALSE; 1685 } 1686 } 1687 } 1688 } 1689 1690 break; 1691 1692 case COM: 1693 /* We have found a common definition for a symbol. */ 1694 if (h->type == bfd_link_hash_new) 1695 bfd_link_add_undef (info->hash, h); 1696 h->type = bfd_link_hash_common; 1697 h->u.c.p = (struct bfd_link_hash_common_entry *) 1698 bfd_hash_allocate (&info->hash->table, 1699 sizeof (struct bfd_link_hash_common_entry)); 1700 if (h->u.c.p == NULL) 1701 return FALSE; 1702 1703 h->u.c.size = value; 1704 1705 /* Select a default alignment based on the size. This may 1706 be overridden by the caller. */ 1707 { 1708 unsigned int power; 1709 1710 power = bfd_log2 (value); 1711 if (power > 4) 1712 power = 4; 1713 h->u.c.p->alignment_power = power; 1714 } 1715 1716 /* The section of a common symbol is only used if the common 1717 symbol is actually allocated. It basically provides a 1718 hook for the linker script to decide which output section 1719 the common symbols should be put in. In most cases, the 1720 section of a common symbol will be bfd_com_section_ptr, 1721 the code here will choose a common symbol section named 1722 "COMMON", and the linker script will contain *(COMMON) in 1723 the appropriate place. A few targets use separate common 1724 sections for small symbols, and they require special 1725 handling. */ 1726 if (section == bfd_com_section_ptr) 1727 { 1728 h->u.c.p->section = bfd_make_section_old_way (abfd, "COMMON"); 1729 h->u.c.p->section->flags = SEC_ALLOC; 1730 } 1731 else if (section->owner != abfd) 1732 { 1733 h->u.c.p->section = bfd_make_section_old_way (abfd, 1734 section->name); 1735 h->u.c.p->section->flags = SEC_ALLOC; 1736 } 1737 else 1738 h->u.c.p->section = section; 1739 break; 1740 1741 case REF: 1742 /* A reference to a defined symbol. */ 1743 if (h->u.undef.next == NULL && info->hash->undefs_tail != h) 1744 h->u.undef.next = h; 1745 break; 1746 1747 case BIG: 1748 /* We have found a common definition for a symbol which 1749 already had a common definition. Use the maximum of the 1750 two sizes, and use the section required by the larger symbol. */ 1751 BFD_ASSERT (h->type == bfd_link_hash_common); 1752 if (! ((*info->callbacks->multiple_common) 1753 (info, h->root.string, 1754 h->u.c.p->section->owner, bfd_link_hash_common, h->u.c.size, 1755 abfd, bfd_link_hash_common, value))) 1756 return FALSE; 1757 if (value > h->u.c.size) 1758 { 1759 unsigned int power; 1760 1761 h->u.c.size = value; 1762 1763 /* Select a default alignment based on the size. This may 1764 be overridden by the caller. */ 1765 power = bfd_log2 (value); 1766 if (power > 4) 1767 power = 4; 1768 h->u.c.p->alignment_power = power; 1769 1770 /* Some systems have special treatment for small commons, 1771 hence we want to select the section used by the larger 1772 symbol. This makes sure the symbol does not go in a 1773 small common section if it is now too large. */ 1774 if (section == bfd_com_section_ptr) 1775 { 1776 h->u.c.p->section 1777 = bfd_make_section_old_way (abfd, "COMMON"); 1778 h->u.c.p->section->flags = SEC_ALLOC; 1779 } 1780 else if (section->owner != abfd) 1781 { 1782 h->u.c.p->section 1783 = bfd_make_section_old_way (abfd, section->name); 1784 h->u.c.p->section->flags = SEC_ALLOC; 1785 } 1786 else 1787 h->u.c.p->section = section; 1788 } 1789 break; 1790 1791 case CREF: 1792 { 1793 bfd *obfd; 1794 1795 /* We have found a common definition for a symbol which 1796 was already defined. FIXME: It would nice if we could 1797 report the BFD which defined an indirect symbol, but we 1798 don't have anywhere to store the information. */ 1799 if (h->type == bfd_link_hash_defined 1800 || h->type == bfd_link_hash_defweak) 1801 obfd = h->u.def.section->owner; 1802 else 1803 obfd = NULL; 1804 if (! ((*info->callbacks->multiple_common) 1805 (info, h->root.string, obfd, h->type, 0, 1806 abfd, bfd_link_hash_common, value))) 1807 return FALSE; 1808 } 1809 break; 1810 1811 case MIND: 1812 /* Multiple indirect symbols. This is OK if they both point 1813 to the same symbol. */ 1814 if (strcmp (h->u.i.link->root.string, string) == 0) 1815 break; 1816 /* Fall through. */ 1817 case MDEF: 1818 /* Handle a multiple definition. */ 1819 if (!info->allow_multiple_definition) 1820 { 1821 asection *msec = NULL; 1822 bfd_vma mval = 0; 1823 1824 switch (h->type) 1825 { 1826 case bfd_link_hash_defined: 1827 msec = h->u.def.section; 1828 mval = h->u.def.value; 1829 break; 1830 case bfd_link_hash_indirect: 1831 msec = bfd_ind_section_ptr; 1832 mval = 0; 1833 break; 1834 default: 1835 abort (); 1836 } 1837 1838 /* Ignore a redefinition of an absolute symbol to the 1839 same value; it's harmless. */ 1840 if (h->type == bfd_link_hash_defined 1841 && bfd_is_abs_section (msec) 1842 && bfd_is_abs_section (section) 1843 && value == mval) 1844 break; 1845 1846 if (! ((*info->callbacks->multiple_definition) 1847 (info, h->root.string, msec->owner, msec, mval, 1848 abfd, section, value))) 1849 return FALSE; 1850 } 1851 break; 1852 1853 case CIND: 1854 /* Create an indirect symbol from an existing common symbol. */ 1855 BFD_ASSERT (h->type == bfd_link_hash_common); 1856 if (! ((*info->callbacks->multiple_common) 1857 (info, h->root.string, 1858 h->u.c.p->section->owner, bfd_link_hash_common, h->u.c.size, 1859 abfd, bfd_link_hash_indirect, 0))) 1860 return FALSE; 1861 /* Fall through. */ 1862 case IND: 1863 /* Create an indirect symbol. */ 1864 { 1865 struct bfd_link_hash_entry *inh; 1866 1867 /* STRING is the name of the symbol we want to indirect 1868 to. */ 1869 inh = bfd_wrapped_link_hash_lookup (abfd, info, string, TRUE, 1870 copy, FALSE); 1871 if (inh == NULL) 1872 return FALSE; 1873 if (inh->type == bfd_link_hash_indirect 1874 && inh->u.i.link == h) 1875 { 1876 (*_bfd_error_handler) 1877 (_("%B: indirect symbol `%s' to `%s' is a loop"), 1878 abfd, name, string); 1879 bfd_set_error (bfd_error_invalid_operation); 1880 return FALSE; 1881 } 1882 if (inh->type == bfd_link_hash_new) 1883 { 1884 inh->type = bfd_link_hash_undefined; 1885 inh->u.undef.abfd = abfd; 1886 bfd_link_add_undef (info->hash, inh); 1887 } 1888 1889 /* If the indirect symbol has been referenced, we need to 1890 push the reference down to the symbol we are 1891 referencing. */ 1892 if (h->type != bfd_link_hash_new) 1893 { 1894 row = UNDEF_ROW; 1895 cycle = TRUE; 1896 } 1897 1898 h->type = bfd_link_hash_indirect; 1899 h->u.i.link = inh; 1900 } 1901 break; 1902 1903 case SET: 1904 /* Add an entry to a set. */ 1905 if (! (*info->callbacks->add_to_set) (info, h, BFD_RELOC_CTOR, 1906 abfd, section, value)) 1907 return FALSE; 1908 break; 1909 1910 case WARNC: 1911 /* Issue a warning and cycle. */ 1912 if (h->u.i.warning != NULL) 1913 { 1914 if (! (*info->callbacks->warning) (info, h->u.i.warning, 1915 h->root.string, abfd, 1916 NULL, 0)) 1917 return FALSE; 1918 /* Only issue a warning once. */ 1919 h->u.i.warning = NULL; 1920 } 1921 /* Fall through. */ 1922 case CYCLE: 1923 /* Try again with the referenced symbol. */ 1924 h = h->u.i.link; 1925 cycle = TRUE; 1926 break; 1927 1928 case REFC: 1929 /* A reference to an indirect symbol. */ 1930 if (h->u.undef.next == NULL && info->hash->undefs_tail != h) 1931 h->u.undef.next = h; 1932 h = h->u.i.link; 1933 cycle = TRUE; 1934 break; 1935 1936 case WARN: 1937 /* Issue a warning. */ 1938 if (! (*info->callbacks->warning) (info, string, h->root.string, 1939 hash_entry_bfd (h), NULL, 0)) 1940 return FALSE; 1941 break; 1942 1943 case CWARN: 1944 /* Warn if this symbol has been referenced already, 1945 otherwise add a warning. A symbol has been referenced if 1946 the u.undef.next field is not NULL, or it is the tail of the 1947 undefined symbol list. The REF case above helps to 1948 ensure this. */ 1949 if (h->u.undef.next != NULL || info->hash->undefs_tail == h) 1950 { 1951 if (! (*info->callbacks->warning) (info, string, h->root.string, 1952 hash_entry_bfd (h), NULL, 0)) 1953 return FALSE; 1954 break; 1955 } 1956 /* Fall through. */ 1957 case MWARN: 1958 /* Make a warning symbol. */ 1959 { 1960 struct bfd_link_hash_entry *sub; 1961 1962 /* STRING is the warning to give. */ 1963 sub = ((struct bfd_link_hash_entry *) 1964 ((*info->hash->table.newfunc) 1965 (NULL, &info->hash->table, h->root.string))); 1966 if (sub == NULL) 1967 return FALSE; 1968 *sub = *h; 1969 sub->type = bfd_link_hash_warning; 1970 sub->u.i.link = h; 1971 if (! copy) 1972 sub->u.i.warning = string; 1973 else 1974 { 1975 char *w; 1976 size_t len = strlen (string) + 1; 1977 1978 w = (char *) bfd_hash_allocate (&info->hash->table, len); 1979 if (w == NULL) 1980 return FALSE; 1981 memcpy (w, string, len); 1982 sub->u.i.warning = w; 1983 } 1984 1985 bfd_hash_replace (&info->hash->table, 1986 (struct bfd_hash_entry *) h, 1987 (struct bfd_hash_entry *) sub); 1988 if (hashp != NULL) 1989 *hashp = sub; 1990 } 1991 break; 1992 } 1993 } 1994 while (cycle); 1995 1996 return TRUE; 1997 } 1998 1999 /* Generic final link routine. */ 2000 2001 bfd_boolean 2002 _bfd_generic_final_link (bfd *abfd, struct bfd_link_info *info) 2003 { 2004 bfd *sub; 2005 asection *o; 2006 struct bfd_link_order *p; 2007 size_t outsymalloc; 2008 struct generic_write_global_symbol_info wginfo; 2009 2010 bfd_get_outsymbols (abfd) = NULL; 2011 bfd_get_symcount (abfd) = 0; 2012 outsymalloc = 0; 2013 2014 /* Mark all sections which will be included in the output file. */ 2015 for (o = abfd->sections; o != NULL; o = o->next) 2016 for (p = o->map_head.link_order; p != NULL; p = p->next) 2017 if (p->type == bfd_indirect_link_order) 2018 p->u.indirect.section->linker_mark = TRUE; 2019 2020 /* Build the output symbol table. */ 2021 for (sub = info->input_bfds; sub != NULL; sub = sub->link_next) 2022 if (! _bfd_generic_link_output_symbols (abfd, sub, info, &outsymalloc)) 2023 return FALSE; 2024 2025 /* Accumulate the global symbols. */ 2026 wginfo.info = info; 2027 wginfo.output_bfd = abfd; 2028 wginfo.psymalloc = &outsymalloc; 2029 _bfd_generic_link_hash_traverse (_bfd_generic_hash_table (info), 2030 _bfd_generic_link_write_global_symbol, 2031 &wginfo); 2032 2033 /* Make sure we have a trailing NULL pointer on OUTSYMBOLS. We 2034 shouldn't really need one, since we have SYMCOUNT, but some old 2035 code still expects one. */ 2036 if (! generic_add_output_symbol (abfd, &outsymalloc, NULL)) 2037 return FALSE; 2038 2039 if (info->relocatable) 2040 { 2041 /* Allocate space for the output relocs for each section. */ 2042 for (o = abfd->sections; o != NULL; o = o->next) 2043 { 2044 o->reloc_count = 0; 2045 for (p = o->map_head.link_order; p != NULL; p = p->next) 2046 { 2047 if (p->type == bfd_section_reloc_link_order 2048 || p->type == bfd_symbol_reloc_link_order) 2049 ++o->reloc_count; 2050 else if (p->type == bfd_indirect_link_order) 2051 { 2052 asection *input_section; 2053 bfd *input_bfd; 2054 long relsize; 2055 arelent **relocs; 2056 asymbol **symbols; 2057 long reloc_count; 2058 2059 input_section = p->u.indirect.section; 2060 input_bfd = input_section->owner; 2061 relsize = bfd_get_reloc_upper_bound (input_bfd, 2062 input_section); 2063 if (relsize < 0) 2064 return FALSE; 2065 relocs = (arelent **) bfd_malloc (relsize); 2066 if (!relocs && relsize != 0) 2067 return FALSE; 2068 symbols = _bfd_generic_link_get_symbols (input_bfd); 2069 reloc_count = bfd_canonicalize_reloc (input_bfd, 2070 input_section, 2071 relocs, 2072 symbols); 2073 free (relocs); 2074 if (reloc_count < 0) 2075 return FALSE; 2076 BFD_ASSERT ((unsigned long) reloc_count 2077 == input_section->reloc_count); 2078 o->reloc_count += reloc_count; 2079 } 2080 } 2081 if (o->reloc_count > 0) 2082 { 2083 bfd_size_type amt; 2084 2085 amt = o->reloc_count; 2086 amt *= sizeof (arelent *); 2087 o->orelocation = (struct reloc_cache_entry **) bfd_alloc (abfd, amt); 2088 if (!o->orelocation) 2089 return FALSE; 2090 o->flags |= SEC_RELOC; 2091 /* Reset the count so that it can be used as an index 2092 when putting in the output relocs. */ 2093 o->reloc_count = 0; 2094 } 2095 } 2096 } 2097 2098 /* Handle all the link order information for the sections. */ 2099 for (o = abfd->sections; o != NULL; o = o->next) 2100 { 2101 for (p = o->map_head.link_order; p != NULL; p = p->next) 2102 { 2103 switch (p->type) 2104 { 2105 case bfd_section_reloc_link_order: 2106 case bfd_symbol_reloc_link_order: 2107 if (! _bfd_generic_reloc_link_order (abfd, info, o, p)) 2108 return FALSE; 2109 break; 2110 case bfd_indirect_link_order: 2111 if (! default_indirect_link_order (abfd, info, o, p, TRUE)) 2112 return FALSE; 2113 break; 2114 default: 2115 if (! _bfd_default_link_order (abfd, info, o, p)) 2116 return FALSE; 2117 break; 2118 } 2119 } 2120 } 2121 2122 return TRUE; 2123 } 2124 2125 /* Add an output symbol to the output BFD. */ 2126 2127 static bfd_boolean 2128 generic_add_output_symbol (bfd *output_bfd, size_t *psymalloc, asymbol *sym) 2129 { 2130 if (bfd_get_symcount (output_bfd) >= *psymalloc) 2131 { 2132 asymbol **newsyms; 2133 bfd_size_type amt; 2134 2135 if (*psymalloc == 0) 2136 *psymalloc = 124; 2137 else 2138 *psymalloc *= 2; 2139 amt = *psymalloc; 2140 amt *= sizeof (asymbol *); 2141 newsyms = (asymbol **) bfd_realloc (bfd_get_outsymbols (output_bfd), amt); 2142 if (newsyms == NULL) 2143 return FALSE; 2144 bfd_get_outsymbols (output_bfd) = newsyms; 2145 } 2146 2147 bfd_get_outsymbols (output_bfd) [bfd_get_symcount (output_bfd)] = sym; 2148 if (sym != NULL) 2149 ++ bfd_get_symcount (output_bfd); 2150 2151 return TRUE; 2152 } 2153 2154 /* Handle the symbols for an input BFD. */ 2155 2156 bfd_boolean 2157 _bfd_generic_link_output_symbols (bfd *output_bfd, 2158 bfd *input_bfd, 2159 struct bfd_link_info *info, 2160 size_t *psymalloc) 2161 { 2162 asymbol **sym_ptr; 2163 asymbol **sym_end; 2164 2165 if (!bfd_generic_link_read_symbols (input_bfd)) 2166 return FALSE; 2167 2168 /* Create a filename symbol if we are supposed to. */ 2169 if (info->create_object_symbols_section != NULL) 2170 { 2171 asection *sec; 2172 2173 for (sec = input_bfd->sections; sec != NULL; sec = sec->next) 2174 { 2175 if (sec->output_section == info->create_object_symbols_section) 2176 { 2177 asymbol *newsym; 2178 2179 newsym = bfd_make_empty_symbol (input_bfd); 2180 if (!newsym) 2181 return FALSE; 2182 newsym->name = input_bfd->filename; 2183 newsym->value = 0; 2184 newsym->flags = BSF_LOCAL | BSF_FILE; 2185 newsym->section = sec; 2186 2187 if (! generic_add_output_symbol (output_bfd, psymalloc, 2188 newsym)) 2189 return FALSE; 2190 2191 break; 2192 } 2193 } 2194 } 2195 2196 /* Adjust the values of the globally visible symbols, and write out 2197 local symbols. */ 2198 sym_ptr = _bfd_generic_link_get_symbols (input_bfd); 2199 sym_end = sym_ptr + _bfd_generic_link_get_symcount (input_bfd); 2200 for (; sym_ptr < sym_end; sym_ptr++) 2201 { 2202 asymbol *sym; 2203 struct generic_link_hash_entry *h; 2204 bfd_boolean output; 2205 2206 h = NULL; 2207 sym = *sym_ptr; 2208 if ((sym->flags & (BSF_INDIRECT 2209 | BSF_WARNING 2210 | BSF_GLOBAL 2211 | BSF_CONSTRUCTOR 2212 | BSF_WEAK)) != 0 2213 || bfd_is_und_section (bfd_get_section (sym)) 2214 || bfd_is_com_section (bfd_get_section (sym)) 2215 || bfd_is_ind_section (bfd_get_section (sym))) 2216 { 2217 if (sym->udata.p != NULL) 2218 h = (struct generic_link_hash_entry *) sym->udata.p; 2219 else if ((sym->flags & BSF_CONSTRUCTOR) != 0) 2220 { 2221 /* This case normally means that the main linker code 2222 deliberately ignored this constructor symbol. We 2223 should just pass it through. This will screw up if 2224 the constructor symbol is from a different, 2225 non-generic, object file format, but the case will 2226 only arise when linking with -r, which will probably 2227 fail anyhow, since there will be no way to represent 2228 the relocs in the output format being used. */ 2229 h = NULL; 2230 } 2231 else if (bfd_is_und_section (bfd_get_section (sym))) 2232 h = ((struct generic_link_hash_entry *) 2233 bfd_wrapped_link_hash_lookup (output_bfd, info, 2234 bfd_asymbol_name (sym), 2235 FALSE, FALSE, TRUE)); 2236 else 2237 h = _bfd_generic_link_hash_lookup (_bfd_generic_hash_table (info), 2238 bfd_asymbol_name (sym), 2239 FALSE, FALSE, TRUE); 2240 2241 if (h != NULL) 2242 { 2243 /* Force all references to this symbol to point to 2244 the same area in memory. It is possible that 2245 this routine will be called with a hash table 2246 other than a generic hash table, so we double 2247 check that. */ 2248 if (info->output_bfd->xvec == input_bfd->xvec) 2249 { 2250 if (h->sym != NULL) 2251 *sym_ptr = sym = h->sym; 2252 } 2253 2254 switch (h->root.type) 2255 { 2256 default: 2257 case bfd_link_hash_new: 2258 abort (); 2259 case bfd_link_hash_undefined: 2260 break; 2261 case bfd_link_hash_undefweak: 2262 sym->flags |= BSF_WEAK; 2263 break; 2264 case bfd_link_hash_indirect: 2265 h = (struct generic_link_hash_entry *) h->root.u.i.link; 2266 /* fall through */ 2267 case bfd_link_hash_defined: 2268 sym->flags |= BSF_GLOBAL; 2269 sym->flags &=~ BSF_CONSTRUCTOR; 2270 sym->value = h->root.u.def.value; 2271 sym->section = h->root.u.def.section; 2272 break; 2273 case bfd_link_hash_defweak: 2274 sym->flags |= BSF_WEAK; 2275 sym->flags &=~ BSF_CONSTRUCTOR; 2276 sym->value = h->root.u.def.value; 2277 sym->section = h->root.u.def.section; 2278 break; 2279 case bfd_link_hash_common: 2280 sym->value = h->root.u.c.size; 2281 sym->flags |= BSF_GLOBAL; 2282 if (! bfd_is_com_section (sym->section)) 2283 { 2284 BFD_ASSERT (bfd_is_und_section (sym->section)); 2285 sym->section = bfd_com_section_ptr; 2286 } 2287 /* We do not set the section of the symbol to 2288 h->root.u.c.p->section. That value was saved so 2289 that we would know where to allocate the symbol 2290 if it was defined. In this case the type is 2291 still bfd_link_hash_common, so we did not define 2292 it, so we do not want to use that section. */ 2293 break; 2294 } 2295 } 2296 } 2297 2298 /* This switch is straight from the old code in 2299 write_file_locals in ldsym.c. */ 2300 if (info->strip == strip_all 2301 || (info->strip == strip_some 2302 && bfd_hash_lookup (info->keep_hash, bfd_asymbol_name (sym), 2303 FALSE, FALSE) == NULL)) 2304 output = FALSE; 2305 else if ((sym->flags & (BSF_GLOBAL | BSF_WEAK)) != 0) 2306 { 2307 /* If this symbol is marked as occurring now, rather 2308 than at the end, output it now. This is used for 2309 COFF C_EXT FCN symbols. FIXME: There must be a 2310 better way. */ 2311 if (bfd_asymbol_bfd (sym) == input_bfd 2312 && (sym->flags & BSF_NOT_AT_END) != 0) 2313 output = TRUE; 2314 else 2315 output = FALSE; 2316 } 2317 else if (bfd_is_ind_section (sym->section)) 2318 output = FALSE; 2319 else if ((sym->flags & BSF_DEBUGGING) != 0) 2320 { 2321 if (info->strip == strip_none) 2322 output = TRUE; 2323 else 2324 output = FALSE; 2325 } 2326 else if (bfd_is_und_section (sym->section) 2327 || bfd_is_com_section (sym->section)) 2328 output = FALSE; 2329 else if ((sym->flags & BSF_LOCAL) != 0) 2330 { 2331 if ((sym->flags & BSF_WARNING) != 0) 2332 output = FALSE; 2333 else 2334 { 2335 switch (info->discard) 2336 { 2337 default: 2338 case discard_all: 2339 output = FALSE; 2340 break; 2341 case discard_sec_merge: 2342 output = TRUE; 2343 if (info->relocatable 2344 || ! (sym->section->flags & SEC_MERGE)) 2345 break; 2346 /* FALLTHROUGH */ 2347 case discard_l: 2348 if (bfd_is_local_label (input_bfd, sym)) 2349 output = FALSE; 2350 else 2351 output = TRUE; 2352 break; 2353 case discard_none: 2354 output = TRUE; 2355 break; 2356 } 2357 } 2358 } 2359 else if ((sym->flags & BSF_CONSTRUCTOR)) 2360 { 2361 if (info->strip != strip_all) 2362 output = TRUE; 2363 else 2364 output = FALSE; 2365 } 2366 else 2367 abort (); 2368 2369 /* If this symbol is in a section which is not being included 2370 in the output file, then we don't want to output the 2371 symbol. */ 2372 if (!bfd_is_abs_section (sym->section) 2373 && bfd_section_removed_from_list (output_bfd, 2374 sym->section->output_section)) 2375 output = FALSE; 2376 2377 if (output) 2378 { 2379 if (! generic_add_output_symbol (output_bfd, psymalloc, sym)) 2380 return FALSE; 2381 if (h != NULL) 2382 h->written = TRUE; 2383 } 2384 } 2385 2386 return TRUE; 2387 } 2388 2389 /* Set the section and value of a generic BFD symbol based on a linker 2390 hash table entry. */ 2391 2392 static void 2393 set_symbol_from_hash (asymbol *sym, struct bfd_link_hash_entry *h) 2394 { 2395 switch (h->type) 2396 { 2397 default: 2398 abort (); 2399 break; 2400 case bfd_link_hash_new: 2401 /* This can happen when a constructor symbol is seen but we are 2402 not building constructors. */ 2403 if (sym->section != NULL) 2404 { 2405 BFD_ASSERT ((sym->flags & BSF_CONSTRUCTOR) != 0); 2406 } 2407 else 2408 { 2409 sym->flags |= BSF_CONSTRUCTOR; 2410 sym->section = bfd_abs_section_ptr; 2411 sym->value = 0; 2412 } 2413 break; 2414 case bfd_link_hash_undefined: 2415 sym->section = bfd_und_section_ptr; 2416 sym->value = 0; 2417 break; 2418 case bfd_link_hash_undefweak: 2419 sym->section = bfd_und_section_ptr; 2420 sym->value = 0; 2421 sym->flags |= BSF_WEAK; 2422 break; 2423 case bfd_link_hash_defined: 2424 sym->section = h->u.def.section; 2425 sym->value = h->u.def.value; 2426 break; 2427 case bfd_link_hash_defweak: 2428 sym->flags |= BSF_WEAK; 2429 sym->section = h->u.def.section; 2430 sym->value = h->u.def.value; 2431 break; 2432 case bfd_link_hash_common: 2433 sym->value = h->u.c.size; 2434 if (sym->section == NULL) 2435 sym->section = bfd_com_section_ptr; 2436 else if (! bfd_is_com_section (sym->section)) 2437 { 2438 BFD_ASSERT (bfd_is_und_section (sym->section)); 2439 sym->section = bfd_com_section_ptr; 2440 } 2441 /* Do not set the section; see _bfd_generic_link_output_symbols. */ 2442 break; 2443 case bfd_link_hash_indirect: 2444 case bfd_link_hash_warning: 2445 /* FIXME: What should we do here? */ 2446 break; 2447 } 2448 } 2449 2450 /* Write out a global symbol, if it hasn't already been written out. 2451 This is called for each symbol in the hash table. */ 2452 2453 bfd_boolean 2454 _bfd_generic_link_write_global_symbol (struct generic_link_hash_entry *h, 2455 void *data) 2456 { 2457 struct generic_write_global_symbol_info *wginfo = 2458 (struct generic_write_global_symbol_info *) data; 2459 asymbol *sym; 2460 2461 if (h->root.type == bfd_link_hash_warning) 2462 h = (struct generic_link_hash_entry *) h->root.u.i.link; 2463 2464 if (h->written) 2465 return TRUE; 2466 2467 h->written = TRUE; 2468 2469 if (wginfo->info->strip == strip_all 2470 || (wginfo->info->strip == strip_some 2471 && bfd_hash_lookup (wginfo->info->keep_hash, h->root.root.string, 2472 FALSE, FALSE) == NULL)) 2473 return TRUE; 2474 2475 if (h->sym != NULL) 2476 sym = h->sym; 2477 else 2478 { 2479 sym = bfd_make_empty_symbol (wginfo->output_bfd); 2480 if (!sym) 2481 return FALSE; 2482 sym->name = h->root.root.string; 2483 sym->flags = 0; 2484 } 2485 2486 set_symbol_from_hash (sym, &h->root); 2487 2488 sym->flags |= BSF_GLOBAL; 2489 2490 if (! generic_add_output_symbol (wginfo->output_bfd, wginfo->psymalloc, 2491 sym)) 2492 { 2493 /* FIXME: No way to return failure. */ 2494 abort (); 2495 } 2496 2497 return TRUE; 2498 } 2499 2500 /* Create a relocation. */ 2501 2502 bfd_boolean 2503 _bfd_generic_reloc_link_order (bfd *abfd, 2504 struct bfd_link_info *info, 2505 asection *sec, 2506 struct bfd_link_order *link_order) 2507 { 2508 arelent *r; 2509 2510 if (! info->relocatable) 2511 abort (); 2512 if (sec->orelocation == NULL) 2513 abort (); 2514 2515 r = (arelent *) bfd_alloc (abfd, sizeof (arelent)); 2516 if (r == NULL) 2517 return FALSE; 2518 2519 r->address = link_order->offset; 2520 r->howto = bfd_reloc_type_lookup (abfd, link_order->u.reloc.p->reloc); 2521 if (r->howto == 0) 2522 { 2523 bfd_set_error (bfd_error_bad_value); 2524 return FALSE; 2525 } 2526 2527 /* Get the symbol to use for the relocation. */ 2528 if (link_order->type == bfd_section_reloc_link_order) 2529 r->sym_ptr_ptr = link_order->u.reloc.p->u.section->symbol_ptr_ptr; 2530 else 2531 { 2532 struct generic_link_hash_entry *h; 2533 2534 h = ((struct generic_link_hash_entry *) 2535 bfd_wrapped_link_hash_lookup (abfd, info, 2536 link_order->u.reloc.p->u.name, 2537 FALSE, FALSE, TRUE)); 2538 if (h == NULL 2539 || ! h->written) 2540 { 2541 if (! ((*info->callbacks->unattached_reloc) 2542 (info, link_order->u.reloc.p->u.name, NULL, NULL, 0))) 2543 return FALSE; 2544 bfd_set_error (bfd_error_bad_value); 2545 return FALSE; 2546 } 2547 r->sym_ptr_ptr = &h->sym; 2548 } 2549 2550 /* If this is an inplace reloc, write the addend to the object file. 2551 Otherwise, store it in the reloc addend. */ 2552 if (! r->howto->partial_inplace) 2553 r->addend = link_order->u.reloc.p->addend; 2554 else 2555 { 2556 bfd_size_type size; 2557 bfd_reloc_status_type rstat; 2558 bfd_byte *buf; 2559 bfd_boolean ok; 2560 file_ptr loc; 2561 2562 size = bfd_get_reloc_size (r->howto); 2563 buf = (bfd_byte *) bfd_zmalloc (size); 2564 if (buf == NULL) 2565 return FALSE; 2566 rstat = _bfd_relocate_contents (r->howto, abfd, 2567 (bfd_vma) link_order->u.reloc.p->addend, 2568 buf); 2569 switch (rstat) 2570 { 2571 case bfd_reloc_ok: 2572 break; 2573 default: 2574 case bfd_reloc_outofrange: 2575 abort (); 2576 case bfd_reloc_overflow: 2577 if (! ((*info->callbacks->reloc_overflow) 2578 (info, NULL, 2579 (link_order->type == bfd_section_reloc_link_order 2580 ? bfd_section_name (abfd, link_order->u.reloc.p->u.section) 2581 : link_order->u.reloc.p->u.name), 2582 r->howto->name, link_order->u.reloc.p->addend, 2583 NULL, NULL, 0))) 2584 { 2585 free (buf); 2586 return FALSE; 2587 } 2588 break; 2589 } 2590 loc = link_order->offset * bfd_octets_per_byte (abfd); 2591 ok = bfd_set_section_contents (abfd, sec, buf, loc, size); 2592 free (buf); 2593 if (! ok) 2594 return FALSE; 2595 2596 r->addend = 0; 2597 } 2598 2599 sec->orelocation[sec->reloc_count] = r; 2600 ++sec->reloc_count; 2601 2602 return TRUE; 2603 } 2604 2605 /* Allocate a new link_order for a section. */ 2606 2607 struct bfd_link_order * 2608 bfd_new_link_order (bfd *abfd, asection *section) 2609 { 2610 bfd_size_type amt = sizeof (struct bfd_link_order); 2611 struct bfd_link_order *new_lo; 2612 2613 new_lo = (struct bfd_link_order *) bfd_zalloc (abfd, amt); 2614 if (!new_lo) 2615 return NULL; 2616 2617 new_lo->type = bfd_undefined_link_order; 2618 2619 if (section->map_tail.link_order != NULL) 2620 section->map_tail.link_order->next = new_lo; 2621 else 2622 section->map_head.link_order = new_lo; 2623 section->map_tail.link_order = new_lo; 2624 2625 return new_lo; 2626 } 2627 2628 /* Default link order processing routine. Note that we can not handle 2629 the reloc_link_order types here, since they depend upon the details 2630 of how the particular backends generates relocs. */ 2631 2632 bfd_boolean 2633 _bfd_default_link_order (bfd *abfd, 2634 struct bfd_link_info *info, 2635 asection *sec, 2636 struct bfd_link_order *link_order) 2637 { 2638 switch (link_order->type) 2639 { 2640 case bfd_undefined_link_order: 2641 case bfd_section_reloc_link_order: 2642 case bfd_symbol_reloc_link_order: 2643 default: 2644 abort (); 2645 case bfd_indirect_link_order: 2646 return default_indirect_link_order (abfd, info, sec, link_order, 2647 FALSE); 2648 case bfd_data_link_order: 2649 return default_data_link_order (abfd, info, sec, link_order); 2650 } 2651 } 2652 2653 /* Default routine to handle a bfd_data_link_order. */ 2654 2655 static bfd_boolean 2656 default_data_link_order (bfd *abfd, 2657 struct bfd_link_info *info ATTRIBUTE_UNUSED, 2658 asection *sec, 2659 struct bfd_link_order *link_order) 2660 { 2661 bfd_size_type size; 2662 size_t fill_size; 2663 bfd_byte *fill; 2664 file_ptr loc; 2665 bfd_boolean result; 2666 2667 BFD_ASSERT ((sec->flags & SEC_HAS_CONTENTS) != 0); 2668 2669 size = link_order->size; 2670 if (size == 0) 2671 return TRUE; 2672 2673 fill = link_order->u.data.contents; 2674 fill_size = link_order->u.data.size; 2675 if (fill_size != 0 && fill_size < size) 2676 { 2677 bfd_byte *p; 2678 fill = (bfd_byte *) bfd_malloc (size); 2679 if (fill == NULL) 2680 return FALSE; 2681 p = fill; 2682 if (fill_size == 1) 2683 memset (p, (int) link_order->u.data.contents[0], (size_t) size); 2684 else 2685 { 2686 do 2687 { 2688 memcpy (p, link_order->u.data.contents, fill_size); 2689 p += fill_size; 2690 size -= fill_size; 2691 } 2692 while (size >= fill_size); 2693 if (size != 0) 2694 memcpy (p, link_order->u.data.contents, (size_t) size); 2695 size = link_order->size; 2696 } 2697 } 2698 2699 loc = link_order->offset * bfd_octets_per_byte (abfd); 2700 result = bfd_set_section_contents (abfd, sec, fill, loc, size); 2701 2702 if (fill != link_order->u.data.contents) 2703 free (fill); 2704 return result; 2705 } 2706 2707 /* Default routine to handle a bfd_indirect_link_order. */ 2708 2709 static bfd_boolean 2710 default_indirect_link_order (bfd *output_bfd, 2711 struct bfd_link_info *info, 2712 asection *output_section, 2713 struct bfd_link_order *link_order, 2714 bfd_boolean generic_linker) 2715 { 2716 asection *input_section; 2717 bfd *input_bfd; 2718 bfd_byte *contents = NULL; 2719 bfd_byte *new_contents; 2720 bfd_size_type sec_size; 2721 file_ptr loc; 2722 2723 BFD_ASSERT ((output_section->flags & SEC_HAS_CONTENTS) != 0); 2724 2725 input_section = link_order->u.indirect.section; 2726 input_bfd = input_section->owner; 2727 if (input_section->size == 0) 2728 return TRUE; 2729 2730 BFD_ASSERT (input_section->output_section == output_section); 2731 BFD_ASSERT (input_section->output_offset == link_order->offset); 2732 BFD_ASSERT (input_section->size == link_order->size); 2733 2734 if (info->relocatable 2735 && input_section->reloc_count > 0 2736 && output_section->orelocation == NULL) 2737 { 2738 /* Space has not been allocated for the output relocations. 2739 This can happen when we are called by a specific backend 2740 because somebody is attempting to link together different 2741 types of object files. Handling this case correctly is 2742 difficult, and sometimes impossible. */ 2743 (*_bfd_error_handler) 2744 (_("Attempt to do relocatable link with %s input and %s output"), 2745 bfd_get_target (input_bfd), bfd_get_target (output_bfd)); 2746 bfd_set_error (bfd_error_wrong_format); 2747 return FALSE; 2748 } 2749 2750 if (! generic_linker) 2751 { 2752 asymbol **sympp; 2753 asymbol **symppend; 2754 2755 /* Get the canonical symbols. The generic linker will always 2756 have retrieved them by this point, but we are being called by 2757 a specific linker, presumably because we are linking 2758 different types of object files together. */ 2759 if (!bfd_generic_link_read_symbols (input_bfd)) 2760 return FALSE; 2761 2762 /* Since we have been called by a specific linker, rather than 2763 the generic linker, the values of the symbols will not be 2764 right. They will be the values as seen in the input file, 2765 not the values of the final link. We need to fix them up 2766 before we can relocate the section. */ 2767 sympp = _bfd_generic_link_get_symbols (input_bfd); 2768 symppend = sympp + _bfd_generic_link_get_symcount (input_bfd); 2769 for (; sympp < symppend; sympp++) 2770 { 2771 asymbol *sym; 2772 struct bfd_link_hash_entry *h; 2773 2774 sym = *sympp; 2775 2776 if ((sym->flags & (BSF_INDIRECT 2777 | BSF_WARNING 2778 | BSF_GLOBAL 2779 | BSF_CONSTRUCTOR 2780 | BSF_WEAK)) != 0 2781 || bfd_is_und_section (bfd_get_section (sym)) 2782 || bfd_is_com_section (bfd_get_section (sym)) 2783 || bfd_is_ind_section (bfd_get_section (sym))) 2784 { 2785 /* sym->udata may have been set by 2786 generic_link_add_symbol_list. */ 2787 if (sym->udata.p != NULL) 2788 h = (struct bfd_link_hash_entry *) sym->udata.p; 2789 else if (bfd_is_und_section (bfd_get_section (sym))) 2790 h = bfd_wrapped_link_hash_lookup (output_bfd, info, 2791 bfd_asymbol_name (sym), 2792 FALSE, FALSE, TRUE); 2793 else 2794 h = bfd_link_hash_lookup (info->hash, 2795 bfd_asymbol_name (sym), 2796 FALSE, FALSE, TRUE); 2797 if (h != NULL) 2798 set_symbol_from_hash (sym, h); 2799 } 2800 } 2801 } 2802 2803 if ((output_section->flags & (SEC_GROUP | SEC_LINKER_CREATED)) == SEC_GROUP 2804 && input_section->size != 0) 2805 { 2806 /* Group section contents are set by bfd_elf_set_group_contents. */ 2807 if (!output_bfd->output_has_begun) 2808 { 2809 /* FIXME: This hack ensures bfd_elf_set_group_contents is called. */ 2810 if (!bfd_set_section_contents (output_bfd, output_section, "", 0, 1)) 2811 goto error_return; 2812 } 2813 new_contents = output_section->contents; 2814 BFD_ASSERT (new_contents != NULL); 2815 BFD_ASSERT (input_section->output_offset == 0); 2816 } 2817 else 2818 { 2819 /* Get and relocate the section contents. */ 2820 sec_size = (input_section->rawsize > input_section->size 2821 ? input_section->rawsize 2822 : input_section->size); 2823 contents = (bfd_byte *) bfd_malloc (sec_size); 2824 if (contents == NULL && sec_size != 0) 2825 goto error_return; 2826 new_contents = (bfd_get_relocated_section_contents 2827 (output_bfd, info, link_order, contents, 2828 info->relocatable, 2829 _bfd_generic_link_get_symbols (input_bfd))); 2830 if (!new_contents) 2831 goto error_return; 2832 } 2833 2834 /* Output the section contents. */ 2835 loc = input_section->output_offset * bfd_octets_per_byte (output_bfd); 2836 if (! bfd_set_section_contents (output_bfd, output_section, 2837 new_contents, loc, input_section->size)) 2838 goto error_return; 2839 2840 if (contents != NULL) 2841 free (contents); 2842 return TRUE; 2843 2844 error_return: 2845 if (contents != NULL) 2846 free (contents); 2847 return FALSE; 2848 } 2849 2850 /* A little routine to count the number of relocs in a link_order 2851 list. */ 2852 2853 unsigned int 2854 _bfd_count_link_order_relocs (struct bfd_link_order *link_order) 2855 { 2856 register unsigned int c; 2857 register struct bfd_link_order *l; 2858 2859 c = 0; 2860 for (l = link_order; l != NULL; l = l->next) 2861 { 2862 if (l->type == bfd_section_reloc_link_order 2863 || l->type == bfd_symbol_reloc_link_order) 2864 ++c; 2865 } 2866 2867 return c; 2868 } 2869 2870 /* 2871 FUNCTION 2872 bfd_link_split_section 2873 2874 SYNOPSIS 2875 bfd_boolean bfd_link_split_section (bfd *abfd, asection *sec); 2876 2877 DESCRIPTION 2878 Return nonzero if @var{sec} should be split during a 2879 reloceatable or final link. 2880 2881 .#define bfd_link_split_section(abfd, sec) \ 2882 . BFD_SEND (abfd, _bfd_link_split_section, (abfd, sec)) 2883 . 2884 2885 */ 2886 2887 bfd_boolean 2888 _bfd_generic_link_split_section (bfd *abfd ATTRIBUTE_UNUSED, 2889 asection *sec ATTRIBUTE_UNUSED) 2890 { 2891 return FALSE; 2892 } 2893 2894 /* 2895 FUNCTION 2896 bfd_section_already_linked 2897 2898 SYNOPSIS 2899 void bfd_section_already_linked (bfd *abfd, asection *sec, 2900 struct bfd_link_info *info); 2901 2902 DESCRIPTION 2903 Check if @var{sec} has been already linked during a reloceatable 2904 or final link. 2905 2906 .#define bfd_section_already_linked(abfd, sec, info) \ 2907 . BFD_SEND (abfd, _section_already_linked, (abfd, sec, info)) 2908 . 2909 2910 */ 2911 2912 /* Sections marked with the SEC_LINK_ONCE flag should only be linked 2913 once into the output. This routine checks each section, and 2914 arrange to discard it if a section of the same name has already 2915 been linked. This code assumes that all relevant sections have the 2916 SEC_LINK_ONCE flag set; that is, it does not depend solely upon the 2917 section name. bfd_section_already_linked is called via 2918 bfd_map_over_sections. */ 2919 2920 /* The hash table. */ 2921 2922 static struct bfd_hash_table _bfd_section_already_linked_table; 2923 2924 /* Support routines for the hash table used by section_already_linked, 2925 initialize the table, traverse, lookup, fill in an entry and remove 2926 the table. */ 2927 2928 void 2929 bfd_section_already_linked_table_traverse 2930 (bfd_boolean (*func) (struct bfd_section_already_linked_hash_entry *, 2931 void *), void *info) 2932 { 2933 bfd_hash_traverse (&_bfd_section_already_linked_table, 2934 (bfd_boolean (*) (struct bfd_hash_entry *, 2935 void *)) func, 2936 info); 2937 } 2938 2939 struct bfd_section_already_linked_hash_entry * 2940 bfd_section_already_linked_table_lookup (const char *name) 2941 { 2942 return ((struct bfd_section_already_linked_hash_entry *) 2943 bfd_hash_lookup (&_bfd_section_already_linked_table, name, 2944 TRUE, FALSE)); 2945 } 2946 2947 bfd_boolean 2948 bfd_section_already_linked_table_insert 2949 (struct bfd_section_already_linked_hash_entry *already_linked_list, 2950 asection *sec) 2951 { 2952 struct bfd_section_already_linked *l; 2953 2954 /* Allocate the memory from the same obstack as the hash table is 2955 kept in. */ 2956 l = (struct bfd_section_already_linked *) 2957 bfd_hash_allocate (&_bfd_section_already_linked_table, sizeof *l); 2958 if (l == NULL) 2959 return FALSE; 2960 l->sec = sec; 2961 l->next = already_linked_list->entry; 2962 already_linked_list->entry = l; 2963 return TRUE; 2964 } 2965 2966 static struct bfd_hash_entry * 2967 already_linked_newfunc (struct bfd_hash_entry *entry ATTRIBUTE_UNUSED, 2968 struct bfd_hash_table *table, 2969 const char *string ATTRIBUTE_UNUSED) 2970 { 2971 struct bfd_section_already_linked_hash_entry *ret = 2972 (struct bfd_section_already_linked_hash_entry *) 2973 bfd_hash_allocate (table, sizeof *ret); 2974 2975 if (ret == NULL) 2976 return NULL; 2977 2978 ret->entry = NULL; 2979 2980 return &ret->root; 2981 } 2982 2983 bfd_boolean 2984 bfd_section_already_linked_table_init (void) 2985 { 2986 return bfd_hash_table_init_n (&_bfd_section_already_linked_table, 2987 already_linked_newfunc, 2988 sizeof (struct bfd_section_already_linked_hash_entry), 2989 42); 2990 } 2991 2992 void 2993 bfd_section_already_linked_table_free (void) 2994 { 2995 bfd_hash_table_free (&_bfd_section_already_linked_table); 2996 } 2997 2998 /* This is used on non-ELF inputs. */ 2999 3000 void 3001 _bfd_generic_section_already_linked (bfd *abfd, asection *sec, 3002 struct bfd_link_info *info) 3003 { 3004 flagword flags; 3005 const char *name; 3006 struct bfd_section_already_linked *l; 3007 struct bfd_section_already_linked_hash_entry *already_linked_list; 3008 3009 flags = sec->flags; 3010 if ((flags & SEC_LINK_ONCE) == 0) 3011 return; 3012 3013 /* FIXME: When doing a relocatable link, we may have trouble 3014 copying relocations in other sections that refer to local symbols 3015 in the section being discarded. Those relocations will have to 3016 be converted somehow; as of this writing I'm not sure that any of 3017 the backends handle that correctly. 3018 3019 It is tempting to instead not discard link once sections when 3020 doing a relocatable link (technically, they should be discarded 3021 whenever we are building constructors). However, that fails, 3022 because the linker winds up combining all the link once sections 3023 into a single large link once section, which defeats the purpose 3024 of having link once sections in the first place. */ 3025 3026 name = bfd_get_section_name (abfd, sec); 3027 3028 already_linked_list = bfd_section_already_linked_table_lookup (name); 3029 3030 for (l = already_linked_list->entry; l != NULL; l = l->next) 3031 { 3032 bfd_boolean skip = FALSE; 3033 struct coff_comdat_info *s_comdat 3034 = bfd_coff_get_comdat_section (abfd, sec); 3035 struct coff_comdat_info *l_comdat 3036 = bfd_coff_get_comdat_section (l->sec->owner, l->sec); 3037 3038 /* We may have 3 different sections on the list: group section, 3039 comdat section and linkonce section. SEC may be a linkonce or 3040 comdat section. We always ignore group section. For non-COFF 3041 inputs, we also ignore comdat section. 3042 3043 FIXME: Is that safe to match a linkonce section with a comdat 3044 section for COFF inputs? */ 3045 if ((l->sec->flags & SEC_GROUP) != 0) 3046 skip = TRUE; 3047 else if (bfd_get_flavour (abfd) == bfd_target_coff_flavour) 3048 { 3049 if (s_comdat != NULL 3050 && l_comdat != NULL 3051 && strcmp (s_comdat->name, l_comdat->name) != 0) 3052 skip = TRUE; 3053 } 3054 else if (l_comdat != NULL) 3055 skip = TRUE; 3056 3057 if (!skip) 3058 { 3059 /* The section has already been linked. See if we should 3060 issue a warning. */ 3061 switch (flags & SEC_LINK_DUPLICATES) 3062 { 3063 default: 3064 abort (); 3065 3066 case SEC_LINK_DUPLICATES_DISCARD: 3067 break; 3068 3069 case SEC_LINK_DUPLICATES_ONE_ONLY: 3070 (*_bfd_error_handler) 3071 (_("%B: warning: ignoring duplicate section `%A'\n"), 3072 abfd, sec); 3073 break; 3074 3075 case SEC_LINK_DUPLICATES_SAME_CONTENTS: 3076 /* FIXME: We should really dig out the contents of both 3077 sections and memcmp them. The COFF/PE spec says that 3078 the Microsoft linker does not implement this 3079 correctly, so I'm not going to bother doing it 3080 either. */ 3081 /* Fall through. */ 3082 case SEC_LINK_DUPLICATES_SAME_SIZE: 3083 if (sec->size != l->sec->size) 3084 (*_bfd_error_handler) 3085 (_("%B: warning: duplicate section `%A' has different size\n"), 3086 abfd, sec); 3087 break; 3088 } 3089 3090 /* Set the output_section field so that lang_add_section 3091 does not create a lang_input_section structure for this 3092 section. Since there might be a symbol in the section 3093 being discarded, we must retain a pointer to the section 3094 which we are really going to use. */ 3095 sec->output_section = bfd_abs_section_ptr; 3096 sec->kept_section = l->sec; 3097 3098 return; 3099 } 3100 } 3101 3102 /* This is the first section with this name. Record it. */ 3103 if (! bfd_section_already_linked_table_insert (already_linked_list, sec)) 3104 info->callbacks->einfo (_("%F%P: already_linked_table: %E\n")); 3105 } 3106 3107 /* Convert symbols in excluded output sections to use a kept section. */ 3108 3109 static bfd_boolean 3110 fix_syms (struct bfd_link_hash_entry *h, void *data) 3111 { 3112 bfd *obfd = (bfd *) data; 3113 3114 if (h->type == bfd_link_hash_warning) 3115 h = h->u.i.link; 3116 3117 if (h->type == bfd_link_hash_defined 3118 || h->type == bfd_link_hash_defweak) 3119 { 3120 asection *s = h->u.def.section; 3121 if (s != NULL 3122 && s->output_section != NULL 3123 && (s->output_section->flags & SEC_EXCLUDE) != 0 3124 && bfd_section_removed_from_list (obfd, s->output_section)) 3125 { 3126 asection *op, *op1; 3127 3128 h->u.def.value += s->output_offset + s->output_section->vma; 3129 3130 /* Find preceding kept section. */ 3131 for (op1 = s->output_section->prev; op1 != NULL; op1 = op1->prev) 3132 if ((op1->flags & SEC_EXCLUDE) == 0 3133 && !bfd_section_removed_from_list (obfd, op1)) 3134 break; 3135 3136 /* Find following kept section. Start at prev->next because 3137 other sections may have been added after S was removed. */ 3138 if (s->output_section->prev != NULL) 3139 op = s->output_section->prev->next; 3140 else 3141 op = s->output_section->owner->sections; 3142 for (; op != NULL; op = op->next) 3143 if ((op->flags & SEC_EXCLUDE) == 0 3144 && !bfd_section_removed_from_list (obfd, op)) 3145 break; 3146 3147 /* Choose better of two sections, based on flags. The idea 3148 is to choose a section that will be in the same segment 3149 as S would have been if it was kept. */ 3150 if (op1 == NULL) 3151 { 3152 if (op == NULL) 3153 op = bfd_abs_section_ptr; 3154 } 3155 else if (op == NULL) 3156 op = op1; 3157 else if (((op1->flags ^ op->flags) 3158 & (SEC_ALLOC | SEC_THREAD_LOCAL | SEC_LOAD)) != 0) 3159 { 3160 if (((op->flags ^ s->flags) 3161 & (SEC_ALLOC | SEC_THREAD_LOCAL)) != 0 3162 /* We prefer to choose a loaded section. Section S 3163 doesn't have SEC_LOAD set (it being excluded, that 3164 part of the flag processing didn't happen) so we 3165 can't compare that flag to those of OP and OP1. */ 3166 || ((op1->flags & SEC_LOAD) != 0 3167 && (op->flags & SEC_LOAD) == 0)) 3168 op = op1; 3169 } 3170 else if (((op1->flags ^ op->flags) & SEC_READONLY) != 0) 3171 { 3172 if (((op->flags ^ s->flags) & SEC_READONLY) != 0) 3173 op = op1; 3174 } 3175 else if (((op1->flags ^ op->flags) & SEC_CODE) != 0) 3176 { 3177 if (((op->flags ^ s->flags) & SEC_CODE) != 0) 3178 op = op1; 3179 } 3180 else 3181 { 3182 /* Flags we care about are the same. Prefer the following 3183 section if that will result in a positive valued sym. */ 3184 if (h->u.def.value < op->vma) 3185 op = op1; 3186 } 3187 3188 h->u.def.value -= op->vma; 3189 h->u.def.section = op; 3190 } 3191 } 3192 3193 return TRUE; 3194 } 3195 3196 void 3197 _bfd_fix_excluded_sec_syms (bfd *obfd, struct bfd_link_info *info) 3198 { 3199 bfd_link_hash_traverse (info->hash, fix_syms, obfd); 3200 } 3201 3202 /* 3203 FUNCTION 3204 bfd_generic_define_common_symbol 3205 3206 SYNOPSIS 3207 bfd_boolean bfd_generic_define_common_symbol 3208 (bfd *output_bfd, struct bfd_link_info *info, 3209 struct bfd_link_hash_entry *h); 3210 3211 DESCRIPTION 3212 Convert common symbol @var{h} into a defined symbol. 3213 Return TRUE on success and FALSE on failure. 3214 3215 .#define bfd_define_common_symbol(output_bfd, info, h) \ 3216 . BFD_SEND (output_bfd, _bfd_define_common_symbol, (output_bfd, info, h)) 3217 . 3218 */ 3219 3220 bfd_boolean 3221 bfd_generic_define_common_symbol (bfd *output_bfd, 3222 struct bfd_link_info *info ATTRIBUTE_UNUSED, 3223 struct bfd_link_hash_entry *h) 3224 { 3225 unsigned int power_of_two; 3226 bfd_vma alignment, size; 3227 asection *section; 3228 3229 BFD_ASSERT (h != NULL && h->type == bfd_link_hash_common); 3230 3231 size = h->u.c.size; 3232 power_of_two = h->u.c.p->alignment_power; 3233 section = h->u.c.p->section; 3234 3235 /* Increase the size of the section to align the common symbol. 3236 The alignment must be a power of two. */ 3237 alignment = bfd_octets_per_byte (output_bfd) << power_of_two; 3238 BFD_ASSERT (alignment != 0 && (alignment & -alignment) == alignment); 3239 section->size += alignment - 1; 3240 section->size &= -alignment; 3241 3242 /* Adjust the section's overall alignment if necessary. */ 3243 if (power_of_two > section->alignment_power) 3244 section->alignment_power = power_of_two; 3245 3246 /* Change the symbol from common to defined. */ 3247 h->type = bfd_link_hash_defined; 3248 h->u.def.section = section; 3249 h->u.def.value = section->size; 3250 3251 /* Increase the size of the section. */ 3252 section->size += size; 3253 3254 /* Make sure the section is allocated in memory, and make sure that 3255 it is no longer a common section. */ 3256 section->flags |= SEC_ALLOC; 3257 section->flags &= ~SEC_IS_COMMON; 3258 return TRUE; 3259 } 3260 3261 /* 3262 FUNCTION 3263 bfd_find_version_for_sym 3264 3265 SYNOPSIS 3266 struct bfd_elf_version_tree * bfd_find_version_for_sym 3267 (struct bfd_elf_version_tree *verdefs, 3268 const char *sym_name, bfd_boolean *hide); 3269 3270 DESCRIPTION 3271 Search an elf version script tree for symbol versioning 3272 info and export / don't-export status for a given symbol. 3273 Return non-NULL on success and NULL on failure; also sets 3274 the output @samp{hide} boolean parameter. 3275 3276 */ 3277 3278 struct bfd_elf_version_tree * 3279 bfd_find_version_for_sym (struct bfd_elf_version_tree *verdefs, 3280 const char *sym_name, 3281 bfd_boolean *hide) 3282 { 3283 struct bfd_elf_version_tree *t; 3284 struct bfd_elf_version_tree *local_ver, *global_ver, *exist_ver; 3285 struct bfd_elf_version_tree *star_local_ver, *star_global_ver; 3286 3287 local_ver = NULL; 3288 global_ver = NULL; 3289 star_local_ver = NULL; 3290 star_global_ver = NULL; 3291 exist_ver = NULL; 3292 for (t = verdefs; t != NULL; t = t->next) 3293 { 3294 if (t->globals.list != NULL) 3295 { 3296 struct bfd_elf_version_expr *d = NULL; 3297 3298 while ((d = (*t->match) (&t->globals, d, sym_name)) != NULL) 3299 { 3300 if (d->literal || strcmp (d->pattern, "*") != 0) 3301 global_ver = t; 3302 else 3303 star_global_ver = t; 3304 if (d->symver) 3305 exist_ver = t; 3306 d->script = 1; 3307 /* If the match is a wildcard pattern, keep looking for 3308 a more explicit, perhaps even local, match. */ 3309 if (d->literal) 3310 break; 3311 } 3312 3313 if (d != NULL) 3314 break; 3315 } 3316 3317 if (t->locals.list != NULL) 3318 { 3319 struct bfd_elf_version_expr *d = NULL; 3320 3321 while ((d = (*t->match) (&t->locals, d, sym_name)) != NULL) 3322 { 3323 if (d->literal || strcmp (d->pattern, "*") != 0) 3324 local_ver = t; 3325 else 3326 star_local_ver = t; 3327 /* If the match is a wildcard pattern, keep looking for 3328 a more explicit, perhaps even global, match. */ 3329 if (d->literal) 3330 { 3331 /* An exact match overrides a global wildcard. */ 3332 global_ver = NULL; 3333 star_global_ver = NULL; 3334 break; 3335 } 3336 } 3337 3338 if (d != NULL) 3339 break; 3340 } 3341 } 3342 3343 if (global_ver == NULL && local_ver == NULL) 3344 global_ver = star_global_ver; 3345 3346 if (global_ver != NULL) 3347 { 3348 /* If we already have a versioned symbol that matches the 3349 node for this symbol, then we don't want to create a 3350 duplicate from the unversioned symbol. Instead hide the 3351 unversioned symbol. */ 3352 *hide = exist_ver == global_ver; 3353 return global_ver; 3354 } 3355 3356 if (local_ver == NULL) 3357 local_ver = star_local_ver; 3358 3359 if (local_ver != NULL) 3360 { 3361 *hide = TRUE; 3362 return local_ver; 3363 } 3364 3365 return NULL; 3366 } 3367