include/bfdlink.h

   1 /* bfdlink.h -- header file for BFD link routines
   2    Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2002
   3    Free Software Foundation, Inc.
   4    Written by Steve Chamberlain and Ian Lance Taylor, Cygnus Support.
   5
   6    This file is part of BFD, the Binary File Descriptor library.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  21
  22 #ifndef BFDLINK_H
  23 #define BFDLINK_H
  24
  25 /* Which symbols to strip during a link.  */
  26 enum bfd_link_strip
  27 {
  28   strip_none,           /* Don't strip any symbols.  */
  29   strip_debugger,       /* Strip debugging symbols.  */
  30   strip_some,           /* keep_hash is the list of symbols to keep.  */
  31   strip_all             /* Strip all symbols.  */
  32 };
  33
  34 /* Which local symbols to discard during a link.  This is irrelevant
  35    if strip_all is used.  */
  36 enum bfd_link_discard
  37 {
  38   discard_sec_merge,    /* Discard local temporary symbols in SEC_MERGE
  39                            sections.  */
  40   discard_none,         /* Don't discard any locals.  */
  41   discard_l,            /* Discard local temporary symbols.  */
  42   discard_all           /* Discard all locals.  */
  43 };
  44
  45 /* Describes the type of hash table entry structure being used.
  46    Different hash table structure have different fields and so
  47    support different linking features.  */
  48 enum bfd_link_hash_table_type
  49   {
  50     bfd_link_generic_hash_table,
  51     bfd_link_elf_hash_table
  52   };
  53 \f
  54 /* These are the possible types of an entry in the BFD link hash
  55    table.  */
  56
  57 enum bfd_link_hash_type
  58 {
  59   bfd_link_hash_new,            /* Symbol is new.  */
  60   bfd_link_hash_undefined,      /* Symbol seen before, but undefined.  */
  61   bfd_link_hash_undefweak,      /* Symbol is weak and undefined.  */
  62   bfd_link_hash_defined,        /* Symbol is defined.  */
  63   bfd_link_hash_defweak,        /* Symbol is weak and defined.  */
  64   bfd_link_hash_common,         /* Symbol is common.  */
  65   bfd_link_hash_indirect,       /* Symbol is an indirect link.  */
  66   bfd_link_hash_warning         /* Like indirect, but warn if referenced.  */
  67 };
  68
  69 enum bfd_link_common_skip_ar_aymbols
  70 {
  71   bfd_link_common_skip_none,
  72   bfd_link_common_skip_text,
  73   bfd_link_common_skip_data,
  74   bfd_link_common_skip_all
  75 };
  76
  77 /* The linking routines use a hash table which uses this structure for
  78    its elements.  */
  79
  80 struct bfd_link_hash_entry
  81 {
  82   /* Base hash table entry structure.  */
  83   struct bfd_hash_entry root;
  84   /* Type of this entry.  */
  85   enum bfd_link_hash_type type;
  86
  87   /* Undefined and common symbols are kept in a linked list through
  88      this field.  This field is not in the union because that would
  89      force us to remove entries from the list when we changed their
  90      type, which would force the list to be doubly linked, which would
  91      waste more memory.  When an undefined or common symbol is
  92      created, it should be added to this list, the head of which is in
  93      the link hash table itself.  As symbols are defined, they need
  94      not be removed from the list; anything which reads the list must
  95      doublecheck the symbol type.
  96
  97      Weak symbols are not kept on this list.
  98
  99      Defined and defweak symbols use this field as a reference marker.
 100      If the field is not NULL, or this structure is the tail of the
 101      undefined symbol list, the symbol has been referenced.  If the
 102      symbol is undefined and becomes defined, this field will
 103      automatically be non-NULL since the symbol will have been on the
 104      undefined symbol list.  */
 105   struct bfd_link_hash_entry *next;
 106   /* A union of information depending upon the type.  */
 107   union
 108     {
 109       /* Nothing is kept for bfd_hash_new.  */
 110       /* bfd_link_hash_undefined, bfd_link_hash_undefweak.  */
 111       struct
 112         {
 113           bfd *abfd;            /* BFD symbol was found in.  */
 114         } undef;
 115       /* bfd_link_hash_defined, bfd_link_hash_defweak.  */
 116       struct
 117         {
 118           bfd_vma value;        /* Symbol value.  */
 119           asection *section;    /* Symbol section.  */
 120         } def;
 121       /* bfd_link_hash_indirect, bfd_link_hash_warning.  */
 122       struct
 123         {
 124           struct bfd_link_hash_entry *link;     /* Real symbol.  */
 125           const char *warning;  /* Warning (bfd_link_hash_warning only).  */
 126         } i;
 127       /* bfd_link_hash_common.  */
 128       struct
 129         {
 130           /* The linker needs to know three things about common
 131              symbols: the size, the alignment, and the section in
 132              which the symbol should be placed.  We store the size
 133              here, and we allocate a small structure to hold the
 134              section and the alignment.  The alignment is stored as a
 135              power of two.  We don't store all the information
 136              directly because we don't want to increase the size of
 137              the union; this structure is a major space user in the
 138              linker.  */
 139           bfd_size_type size;   /* Common symbol size.  */
 140           struct bfd_link_hash_common_entry
 141             {
 142               unsigned int alignment_power;     /* Alignment.  */
 143               asection *section;                /* Symbol section.  */
 144             } *p;
 145         } c;
 146     } u;
 147 };
 148
 149 /* This is the link hash table.  It is a derived class of
 150    bfd_hash_table.  */
 151
 152 struct bfd_link_hash_table
 153 {
 154   /* The hash table itself.  */
 155   struct bfd_hash_table table;
 156   /* The back end which created this hash table.  This indicates the
 157      type of the entries in the hash table, which is sometimes
 158      important information when linking object files of different
 159      types together.  */
 160   const bfd_target *creator;
 161   /* A linked list of undefined and common symbols, linked through the
 162      next field in the bfd_link_hash_entry structure.  */
 163   struct bfd_link_hash_entry *undefs;
 164   /* Entries are added to the tail of the undefs list.  */
 165   struct bfd_link_hash_entry *undefs_tail;
 166   /* The type of the ink hash table.  */
 167   enum bfd_link_hash_table_type type;
 168 };
 169
 170 /* Look up an entry in a link hash table.  If FOLLOW is TRUE, this
 171    follows bfd_link_hash_indirect and bfd_link_hash_warning links to
 172    the real symbol.  */
 173 extern struct bfd_link_hash_entry *bfd_link_hash_lookup
 174   PARAMS ((struct bfd_link_hash_table *, const char *, bfd_boolean create,
 175            bfd_boolean copy, bfd_boolean follow));
 176
 177 /* Look up an entry in the main linker hash table if the symbol might
 178    be wrapped.  This should only be used for references to an
 179    undefined symbol, not for definitions of a symbol.  */
 180
 181 extern struct bfd_link_hash_entry *bfd_wrapped_link_hash_lookup
 182   PARAMS ((bfd *, struct bfd_link_info *, const char *, bfd_boolean,
 183            bfd_boolean, bfd_boolean));
 184
 185 /* Traverse a link hash table.  */
 186 extern void bfd_link_hash_traverse
 187   PARAMS ((struct bfd_link_hash_table *,
 188            bfd_boolean (*) (struct bfd_link_hash_entry *, PTR),
 189            PTR));
 190
 191 /* Add an entry to the undefs list.  */
 192 extern void bfd_link_add_undef
 193   PARAMS ((struct bfd_link_hash_table *, struct bfd_link_hash_entry *));
 194
 195 struct bfd_sym_chain
 196 {
 197   struct bfd_sym_chain *next;
 198   const char *name;
 199 };
 200 \f
 201 /* This structure holds all the information needed to communicate
 202    between BFD and the linker when doing a link.  */
 203
 204 struct bfd_link_info
 205 {
 206   /* Function callbacks.  */
 207   const struct bfd_link_callbacks *callbacks;
 208
 209   /* TRUE if BFD should generate a relocateable object file.  */
 210   bfd_boolean relocateable;
 211
 212   /* TRUE if BFD should generate relocation information in the final
 213      executable.  */
 214   bfd_boolean emitrelocations;
 215
 216   /* TRUE if BFD should generate a "task linked" object file,
 217      similar to relocatable but also with globals converted to
 218      statics.  */
 219   bfd_boolean task_link;
 220
 221   /* TRUE if BFD should generate a shared object.  */
 222   bfd_boolean shared;
 223
 224   /* TRUE if BFD should pre-bind symbols in a shared object.  */
 225   bfd_boolean symbolic;
 226
 227   /* TRUE if BFD should export all symbols in the dynamic symbol table
 228      of an executable, rather than only those used.  */
 229   bfd_boolean export_dynamic;
 230
 231   /* TRUE if shared objects should be linked directly, not shared.  */
 232   bfd_boolean static_link;
 233
 234   /* TRUE if the output file should be in a traditional format.  This
 235      is equivalent to the setting of the BFD_TRADITIONAL_FORMAT flag
 236      on the output file, but may be checked when reading the input
 237      files.  */
 238   bfd_boolean traditional_format;
 239
 240   /* TRUE if we want to produced optimized output files.  This might
 241      need much more time and therefore must be explicitly selected.  */
 242   bfd_boolean optimize;
 243
 244   /* TRUE if BFD should generate errors for undefined symbols
 245      even if generating a shared object.  */
 246   bfd_boolean no_undefined;
 247
 248   /* TRUE if BFD should allow undefined symbols in shared objects even
 249      when no_undefined is set to disallow undefined symbols.  The net
 250      result will be that undefined symbols in regular objects will
 251      still trigger an error, but undefined symbols in shared objects
 252      will be ignored.  The implementation of no_undefined makes the
 253      assumption that the runtime linker will choke on undefined
 254      symbols.  However there is at least one system (BeOS) where
 255      undefined symbols in shared libraries is normal since the kernel
 256      patches them at load time to select which function is most
 257      appropriate for the current architecture.  I.E. dynamically
 258      select an appropriate memset function.  Apparently it is also
 259      normal for HPPA shared libraries to have undefined symbols.  */
 260   bfd_boolean allow_shlib_undefined;
 261
 262   /* TRUE if ok to have multiple definition.  */
 263   bfd_boolean allow_multiple_definition;
 264
 265   /* TRUE if ok to have version with no definition.  */
 266   bfd_boolean allow_undefined_version;
 267
 268   /* Which symbols to strip.  */
 269   enum bfd_link_strip strip;
 270
 271   /* Which local symbols to discard.  */
 272   enum bfd_link_discard discard;
 273
 274   /* TRUE if symbols should be retained in memory, FALSE if they
 275      should be freed and reread.  */
 276   bfd_boolean keep_memory;
 277
 278   /* The list of input BFD's involved in the link.  These are chained
 279      together via the link_next field.  */
 280   bfd *input_bfds;
 281
 282   /* If a symbol should be created for each input BFD, this is section
 283      where those symbols should be placed.  It must be a section in
 284      the output BFD.  It may be NULL, in which case no such symbols
 285      will be created.  This is to support CREATE_OBJECT_SYMBOLS in the
 286      linker command language.  */
 287   asection *create_object_symbols_section;
 288
 289   /* List of global symbol names that are starting points for marking
 290      sections against garbage collection.  */
 291   struct bfd_sym_chain *gc_sym_list;
 292
 293   /* Hash table handled by BFD.  */
 294   struct bfd_link_hash_table *hash;
 295
 296   /* Hash table of symbols to keep.  This is NULL unless strip is
 297      strip_some.  */
 298   struct bfd_hash_table *keep_hash;
 299
 300   /* TRUE if every symbol should be reported back via the notice
 301      callback.  */
 302   bfd_boolean notice_all;
 303
 304   /* Hash table of symbols to report back via the notice callback.  If
 305      this is NULL, and notice_all is FALSE, then no symbols are
 306      reported back.  */
 307   struct bfd_hash_table *notice_hash;
 308
 309   /* Hash table of symbols which are being wrapped (the --wrap linker
 310      option).  If this is NULL, no symbols are being wrapped.  */
 311   struct bfd_hash_table *wrap_hash;
 312
 313   /* If a base output file is wanted, then this points to it */
 314   PTR base_file;
 315
 316   /* If non-zero, specifies that branches which are problematic for the
 317   MPC860 C0 (or earlier) should be checked for and modified.  It gives the
 318   number of bytes that should be checked at the end of each text page. */
 319   int mpc860c0;
 320
 321   /* The function to call when the executable or shared object is
 322      loaded.  */
 323   const char *init_function;
 324
 325   /* The function to call when the executable or shared object is
 326      unloaded.  */
 327   const char *fini_function;
 328
 329   /* TRUE if the new ELF dynamic tags are enabled. */
 330   bfd_boolean new_dtags;
 331
 332   /* May be used to set DT_FLAGS for ELF. */
 333   bfd_vma flags;
 334
 335   /* May be used to set DT_FLAGS_1 for ELF. */
 336   bfd_vma flags_1;
 337
 338   /* Non-zero if auto-import thunks for DATA items in pei386 DLLs
 339      should be generated/linked against.  Set to 1 if this feature
 340      is explicitly requested by the user, -1 if enabled by default.  */
 341   int pei386_auto_import;
 342
 343   /* Non-zero if runtime relocs for DATA items with non-zero addends
 344      in pei386 DLLs should be generated.  Set to 1 if this feature
 345      is explicitly requested by the user, -1 if enabled by default.  */
 346   int pei386_runtime_pseudo_reloc;
 347
 348   /* TRUE if non-PLT relocs should be merged into one reloc section
 349      and sorted so that relocs against the same symbol come together.  */
 350   bfd_boolean combreloc;
 351
 352   /* TRUE if executable should not contain copy relocs.
 353      Setting this true may result in a non-sharable text segment.  */
 354   bfd_boolean nocopyreloc;
 355
 356   /* TRUE if .eh_frame_hdr section and PT_GNU_EH_FRAME ELF segment
 357      should be created.  */
 358   bfd_boolean eh_frame_hdr;
 359
 360   /* How many spare .dynamic DT_NULL entries should be added?  */
 361   unsigned int spare_dynamic_tags;
 362
 363   /* Criteria for skipping symbols when detemining
 364      whether to include an object from an archive. */
 365   enum bfd_link_common_skip_ar_aymbols common_skip_ar_aymbols;
 366 };
 367
 368 /* This structures holds a set of callback functions.  These are
 369    called by the BFD linker routines.  The first argument to each
 370    callback function is the bfd_link_info structure being used.  Each
 371    function returns a boolean value.  If the function returns FALSE,
 372    then the BFD function which called it will return with a failure
 373    indication.  */
 374
 375 struct bfd_link_callbacks
 376 {
 377   /* A function which is called when an object is added from an
 378      archive.  ABFD is the archive element being added.  NAME is the
 379      name of the symbol which caused the archive element to be pulled
 380      in.  */
 381   bfd_boolean (*add_archive_element)
 382     PARAMS ((struct bfd_link_info *, bfd *abfd, const char *name));
 383   /* A function which is called when a symbol is found with multiple
 384      definitions.  NAME is the symbol which is defined multiple times.
 385      OBFD is the old BFD, OSEC is the old section, OVAL is the old
 386      value, NBFD is the new BFD, NSEC is the new section, and NVAL is
 387      the new value.  OBFD may be NULL.  OSEC and NSEC may be
 388      bfd_com_section or bfd_ind_section.  */
 389   bfd_boolean (*multiple_definition)
 390     PARAMS ((struct bfd_link_info *, const char *name,
 391              bfd *obfd, asection *osec, bfd_vma oval,
 392              bfd *nbfd, asection *nsec, bfd_vma nval));
 393   /* A function which is called when a common symbol is defined
 394      multiple times.  NAME is the symbol appearing multiple times.
 395      OBFD is the BFD of the existing symbol; it may be NULL if this is
 396      not known.  OTYPE is the type of the existing symbol, which may
 397      be bfd_link_hash_defined, bfd_link_hash_defweak,
 398      bfd_link_hash_common, or bfd_link_hash_indirect.  If OTYPE is
 399      bfd_link_hash_common, OSIZE is the size of the existing symbol.
 400      NBFD is the BFD of the new symbol.  NTYPE is the type of the new
 401      symbol, one of bfd_link_hash_defined, bfd_link_hash_common, or
 402      bfd_link_hash_indirect.  If NTYPE is bfd_link_hash_common, NSIZE
 403      is the size of the new symbol.  */
 404   bfd_boolean (*multiple_common)
 405     PARAMS ((struct bfd_link_info *, const char *name,
 406              bfd *obfd, enum bfd_link_hash_type otype, bfd_vma osize,
 407              bfd *nbfd, enum bfd_link_hash_type ntype, bfd_vma nsize));
 408   /* A function which is called to add a symbol to a set.  ENTRY is
 409      the link hash table entry for the set itself (e.g.,
 410      __CTOR_LIST__).  RELOC is the relocation to use for an entry in
 411      the set when generating a relocateable file, and is also used to
 412      get the size of the entry when generating an executable file.
 413      ABFD, SEC and VALUE identify the value to add to the set.  */
 414   bfd_boolean (*add_to_set)
 415     PARAMS ((struct bfd_link_info *, struct bfd_link_hash_entry *entry,
 416              bfd_reloc_code_real_type reloc, bfd *abfd, asection *sec,
 417              bfd_vma value));
 418   /* A function which is called when the name of a g++ constructor or
 419      destructor is found.  This is only called by some object file
 420      formats.  CONSTRUCTOR is TRUE for a constructor, FALSE for a
 421      destructor.  This will use BFD_RELOC_CTOR when generating a
 422      relocateable file.  NAME is the name of the symbol found.  ABFD,
 423      SECTION and VALUE are the value of the symbol.  */
 424   bfd_boolean (*constructor)
 425     PARAMS ((struct bfd_link_info *, bfd_boolean constructor,
 426              const char *name, bfd *abfd, asection *sec, bfd_vma value));
 427   /* A function which is called to issue a linker warning.  For
 428      example, this is called when there is a reference to a warning
 429      symbol.  WARNING is the warning to be issued.  SYMBOL is the name
 430      of the symbol which triggered the warning; it may be NULL if
 431      there is none.  ABFD, SECTION and ADDRESS identify the location
 432      which trigerred the warning; either ABFD or SECTION or both may
 433      be NULL if the location is not known.  */
 434   bfd_boolean (*warning)
 435     PARAMS ((struct bfd_link_info *, const char *warning, const char *symbol,
 436              bfd *abfd, asection *section, bfd_vma address));
 437   /* A function which is called when a relocation is attempted against
 438      an undefined symbol.  NAME is the symbol which is undefined.
 439      ABFD, SECTION and ADDRESS identify the location from which the
 440      reference is made. FATAL indicates whether an undefined symbol is
 441      a fatal error or not. In some cases SECTION may be NULL.  */
 442   bfd_boolean (*undefined_symbol)
 443     PARAMS ((struct bfd_link_info *, const char *name, bfd *abfd,
 444              asection *section, bfd_vma address, bfd_boolean fatal));
 445   /* A function which is called when a reloc overflow occurs.  NAME is
 446      the name of the symbol or section the reloc is against,
 447      RELOC_NAME is the name of the relocation, and ADDEND is any
 448      addend that is used.  ABFD, SECTION and ADDRESS identify the
 449      location at which the overflow occurs; if this is the result of a
 450      bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
 451      ABFD will be NULL.  */
 452   bfd_boolean (*reloc_overflow)
 453     PARAMS ((struct bfd_link_info *, const char *name, const char *reloc_name,
 454              bfd_vma addend, bfd *abfd, asection *section, bfd_vma address));
 455   /* A function which is called when a dangerous reloc is performed.
 456      The canonical example is an a29k IHCONST reloc which does not
 457      follow an IHIHALF reloc.  MESSAGE is an appropriate message.
 458      ABFD, SECTION and ADDRESS identify the location at which the
 459      problem occurred; if this is the result of a
 460      bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
 461      ABFD will be NULL.  */
 462   bfd_boolean (*reloc_dangerous)
 463     PARAMS ((struct bfd_link_info *, const char *message,
 464              bfd *abfd, asection *section, bfd_vma address));
 465   /* A function which is called when a reloc is found to be attached
 466      to a symbol which is not being written out.  NAME is the name of
 467      the symbol.  ABFD, SECTION and ADDRESS identify the location of
 468      the reloc; if this is the result of a
 469      bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
 470      ABFD will be NULL.  */
 471   bfd_boolean (*unattached_reloc)
 472     PARAMS ((struct bfd_link_info *, const char *name,
 473              bfd *abfd, asection *section, bfd_vma address));
 474   /* A function which is called when a symbol in notice_hash is
 475      defined or referenced.  NAME is the symbol.  ABFD, SECTION and
 476      ADDRESS are the value of the symbol.  If SECTION is
 477      bfd_und_section, this is a reference.  */
 478   bfd_boolean (*notice)
 479     PARAMS ((struct bfd_link_info *, const char *name,
 480              bfd *abfd, asection *section, bfd_vma address));
 481 };
 482 \f
 483 /* The linker builds link_order structures which tell the code how to
 484    include input data in the output file.  */
 485
 486 /* These are the types of link_order structures.  */
 487
 488 enum bfd_link_order_type
 489 {
 490   bfd_undefined_link_order,     /* Undefined.  */
 491   bfd_indirect_link_order,      /* Built from a section.  */
 492   bfd_data_link_order,          /* Set to explicit data.  */
 493   bfd_section_reloc_link_order, /* Relocate against a section.  */
 494   bfd_symbol_reloc_link_order   /* Relocate against a symbol.  */
 495 };
 496
 497 /* This is the link_order structure itself.  These form a chain
 498    attached to the section whose contents they are describing.  */
 499
 500 struct bfd_link_order
 501 {
 502   /* Next link_order in chain.  */
 503   struct bfd_link_order *next;
 504   /* Type of link_order.  */
 505   enum bfd_link_order_type type;
 506   /* Offset within output section.  */
 507   bfd_vma offset;
 508   /* Size within output section.  */
 509   bfd_size_type size;
 510   /* Type specific information.  */
 511   union
 512     {
 513       struct
 514         {
 515           /* Section to include.  If this is used, then
 516              section->output_section must be the section the
 517              link_order is attached to, section->output_offset must
 518              equal the link_order offset field, and section->_raw_size
 519              must equal the link_order size field.  Maybe these
 520              restrictions should be relaxed someday.  */
 521           asection *section;
 522         } indirect;
 523       struct
 524         {
 525           /* Size of contents, or zero when contents size == size
 526              within output section.
 527              A non-zero value allows filling of the output section
 528              with an arbitrary repeated pattern.  */
 529           unsigned int size;
 530           /* Data to put into file.  */
 531           bfd_byte *contents;
 532         } data;
 533       struct
 534         {
 535           /* Description of reloc to generate.  Used for
 536              bfd_section_reloc_link_order and
 537              bfd_symbol_reloc_link_order.  */
 538           struct bfd_link_order_reloc *p;
 539         } reloc;
 540     } u;
 541 };
 542
 543 /* A linker order of type bfd_section_reloc_link_order or
 544    bfd_symbol_reloc_link_order means to create a reloc against a
 545    section or symbol, respectively.  This is used to implement -Ur to
 546    generate relocs for the constructor tables.  The
 547    bfd_link_order_reloc structure describes the reloc that BFD should
 548    create.  It is similar to a arelent, but I didn't use arelent
 549    because the linker does not know anything about most symbols, and
 550    any asymbol structure it creates will be partially meaningless.
 551    This information could logically be in the bfd_link_order struct,
 552    but I didn't want to waste the space since these types of relocs
 553    are relatively rare.  */
 554
 555 struct bfd_link_order_reloc
 556 {
 557   /* Reloc type.  */
 558   bfd_reloc_code_real_type reloc;
 559
 560   union
 561     {
 562       /* For type bfd_section_reloc_link_order, this is the section
 563          the reloc should be against.  This must be a section in the
 564          output BFD, not any of the input BFDs.  */
 565       asection *section;
 566       /* For type bfd_symbol_reloc_link_order, this is the name of the
 567          symbol the reloc should be against.  */
 568       const char *name;
 569     } u;
 570
 571   /* Addend to use.  The object file should contain zero.  The BFD
 572      backend is responsible for filling in the contents of the object
 573      file correctly.  For some object file formats (e.g., COFF) the
 574      addend must be stored into in the object file, and for some
 575      (e.g., SPARC a.out) it is kept in the reloc.  */
 576   bfd_vma addend;
 577 };
 578
 579 /* Allocate a new link_order for a section.  */
 580 extern struct bfd_link_order *bfd_new_link_order PARAMS ((bfd *, asection *));
 581
 582 /* These structures are used to describe version information for the
 583    ELF linker.  These structures could be manipulated entirely inside
 584    BFD, but it would be a pain.  Instead, the regular linker sets up
 585    these structures, and then passes them into BFD.  */
 586
 587 /* Regular expressions for a version.  */
 588
 589 struct bfd_elf_version_expr
 590 {
 591   /* Next regular expression for this version.  */
 592   struct bfd_elf_version_expr *next;
 593   /* Regular expression.  */
 594   const char *pattern;
 595   /* Matching function.  */
 596   int (*match) PARAMS ((struct bfd_elf_version_expr *, const char *));
 597   /* Defined by ".symver".  */
 598   unsigned int symver: 1;
 599   /* Defined by version script.  */
 600   unsigned int script : 1;
 601 };
 602
 603 /* Version dependencies.  */
 604
 605 struct bfd_elf_version_deps
 606 {
 607   /* Next dependency for this version.  */
 608   struct bfd_elf_version_deps *next;
 609   /* The version which this version depends upon.  */
 610   struct bfd_elf_version_tree *version_needed;
 611 };
 612
 613 /* A node in the version tree.  */
 614
 615 struct bfd_elf_version_tree
 616 {
 617   /* Next version.  */
 618   struct bfd_elf_version_tree *next;
 619   /* Name of this version.  */
 620   const char *name;
 621   /* Version number.  */
 622   unsigned int vernum;
 623   /* Regular expressions for global symbols in this version.  */
 624   struct bfd_elf_version_expr *globals;
 625   /* Regular expressions for local symbols in this version.  */
 626   struct bfd_elf_version_expr *locals;
 627   /* List of versions which this version depends upon.  */
 628   struct bfd_elf_version_deps *deps;
 629   /* Index of the version name.  This is used within BFD.  */
 630   unsigned int name_indx;
 631   /* Whether this version tree was used.  This is used within BFD.  */
 632   int used;
 633 };
 634
 635 #endif