include/bfdlink.h

   1 /* bfdlink.h -- header file for BFD link routines
   2    Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2002, 2003,
   3    2004 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
  85   /* Type of this entry.  */
  86   enum bfd_link_hash_type type;
  87
  88   /* A union of information depending upon the type.  */
  89   union
  90     {
  91       /* Nothing is kept for bfd_hash_new.  */
  92       /* bfd_link_hash_undefined, bfd_link_hash_undefweak.  */
  93       struct
  94         {
  95           /* Undefined and common symbols are kept in a linked list through
  96              this field.  This field is present in all of the union element
  97              so that we don't need to remove entries from the list when we
  98              change their type.  Removing entries would either require the
  99              list to be doubly linked, which would waste more memory, or
 100              require a traversal.  When an undefined or common symbol is
 101              created, it should be added to this list, the head of which is in
 102              the link hash table itself.  As symbols are defined, they need
 103              not be removed from the list; anything which reads the list must
 104              doublecheck the symbol type.
 105
 106              Weak symbols are not kept on this list.
 107
 108              Defined and defweak symbols use this field as a reference marker.
 109              If the field is not NULL, or this structure is the tail of the
 110              undefined symbol list, the symbol has been referenced.  If the
 111              symbol is undefined and becomes defined, this field will
 112              automatically be non-NULL since the symbol will have been on the
 113              undefined symbol list.  */
 114           struct bfd_link_hash_entry *next;
 115           bfd *abfd;            /* BFD symbol was found in.  */
 116         } undef;
 117       /* bfd_link_hash_defined, bfd_link_hash_defweak.  */
 118       struct
 119         {
 120           struct bfd_link_hash_entry *next;
 121           asection *section;    /* Symbol section.  */
 122           bfd_vma value;        /* Symbol value.  */
 123         } def;
 124       /* bfd_link_hash_indirect, bfd_link_hash_warning.  */
 125       struct
 126         {
 127           struct bfd_link_hash_entry *next;
 128           struct bfd_link_hash_entry *link;     /* Real symbol.  */
 129           const char *warning;  /* Warning (bfd_link_hash_warning only).  */
 130         } i;
 131       /* bfd_link_hash_common.  */
 132       struct
 133         {
 134           struct bfd_link_hash_entry *next;
 135           /* The linker needs to know three things about common
 136              symbols: the size, the alignment, and the section in
 137              which the symbol should be placed.  We store the size
 138              here, and we allocate a small structure to hold the
 139              section and the alignment.  The alignment is stored as a
 140              power of two.  We don't store all the information
 141              directly because we don't want to increase the size of
 142              the union; this structure is a major space user in the
 143              linker.  */
 144           struct bfd_link_hash_common_entry
 145             {
 146               unsigned int alignment_power;     /* Alignment.  */
 147               asection *section;                /* Symbol section.  */
 148             } *p;
 149           bfd_size_type size;   /* Common symbol size.  */
 150         } c;
 151     } u;
 152 };
 153
 154 /* This is the link hash table.  It is a derived class of
 155    bfd_hash_table.  */
 156
 157 struct bfd_link_hash_table
 158 {
 159   /* The hash table itself.  */
 160   struct bfd_hash_table table;
 161   /* The back end which created this hash table.  This indicates the
 162      type of the entries in the hash table, which is sometimes
 163      important information when linking object files of different
 164      types together.  */
 165   const bfd_target *creator;
 166   /* A linked list of undefined and common symbols, linked through the
 167      next field in the bfd_link_hash_entry structure.  */
 168   struct bfd_link_hash_entry *undefs;
 169   /* Entries are added to the tail of the undefs list.  */
 170   struct bfd_link_hash_entry *undefs_tail;
 171   /* The type of the link hash table.  */
 172   enum bfd_link_hash_table_type type;
 173 };
 174
 175 /* Look up an entry in a link hash table.  If FOLLOW is TRUE, this
 176    follows bfd_link_hash_indirect and bfd_link_hash_warning links to
 177    the real symbol.  */
 178 extern struct bfd_link_hash_entry *bfd_link_hash_lookup
 179   (struct bfd_link_hash_table *, const char *, bfd_boolean create,
 180    bfd_boolean copy, bfd_boolean follow);
 181
 182 /* Look up an entry in the main linker hash table if the symbol might
 183    be wrapped.  This should only be used for references to an
 184    undefined symbol, not for definitions of a symbol.  */
 185
 186 extern struct bfd_link_hash_entry *bfd_wrapped_link_hash_lookup
 187   (bfd *, struct bfd_link_info *, const char *, bfd_boolean,
 188    bfd_boolean, bfd_boolean);
 189
 190 /* Traverse a link hash table.  */
 191 extern void bfd_link_hash_traverse
 192   (struct bfd_link_hash_table *,
 193     bfd_boolean (*) (struct bfd_link_hash_entry *, void *),
 194     void *);
 195
 196 /* Add an entry to the undefs list.  */
 197 extern void bfd_link_add_undef
 198   (struct bfd_link_hash_table *, struct bfd_link_hash_entry *);
 199
 200 struct bfd_sym_chain
 201 {
 202   struct bfd_sym_chain *next;
 203   const char *name;
 204 };
 205 \f
 206 /* How to handle unresolved symbols.
 207    There are four possibilities which are enumerated below:  */
 208 enum report_method
 209 {
 210   /* This is the initial value when then link_info structure is created.
 211      It allows the various stages of the linker to determine whether they
 212      allowed to set the value.  */
 213   RM_NOT_YET_SET = 0,
 214   RM_IGNORE,
 215   RM_GENERATE_WARNING,
 216   RM_GENERATE_ERROR
 217 };
 218
 219 /* This structure holds all the information needed to communicate
 220    between BFD and the linker when doing a link.  */
 221
 222 struct bfd_link_info
 223 {
 224   /* TRUE if BFD should generate a relocatable object file.  */
 225   unsigned int relocatable: 1;
 226
 227   /* TRUE if BFD should generate relocation information in the final
 228      executable.  */
 229   unsigned int emitrelocations: 1;
 230
 231   /* TRUE if BFD should generate a "task linked" object file,
 232      similar to relocatable but also with globals converted to
 233      statics.  */
 234   unsigned int task_link: 1;
 235
 236   /* TRUE if BFD should generate a shared object.  */
 237   unsigned int shared: 1;
 238
 239   /* TRUE if BFD should pre-bind symbols in a shared object.  */
 240   unsigned int symbolic: 1;
 241
 242   /* TRUE if BFD should export all symbols in the dynamic symbol table
 243      of an executable, rather than only those used.  */
 244   unsigned int export_dynamic: 1;
 245
 246   /* TRUE if shared objects should be linked directly, not shared.  */
 247   unsigned int static_link: 1;
 248
 249   /* TRUE if the output file should be in a traditional format.  This
 250      is equivalent to the setting of the BFD_TRADITIONAL_FORMAT flag
 251      on the output file, but may be checked when reading the input
 252      files.  */
 253   unsigned int traditional_format: 1;
 254
 255   /* TRUE if we want to produced optimized output files.  This might
 256      need much more time and therefore must be explicitly selected.  */
 257   unsigned int optimize: 1;
 258
 259   /* TRUE if ok to have multiple definition.  */
 260   unsigned int allow_multiple_definition: 1;
 261
 262   /* TRUE if ok to have version with no definition.  */
 263   unsigned int allow_undefined_version: 1;
 264
 265   /* TRUE if a default symbol version should be created and used for
 266      exported symbols.  */
 267   unsigned int create_default_symver: 1;
 268
 269   /* TRUE if a default symbol version should be created and used for
 270      imported symbols.  */
 271   unsigned int default_imported_symver: 1;
 272
 273   /* TRUE if symbols should be retained in memory, FALSE if they
 274      should be freed and reread.  */
 275   unsigned int keep_memory: 1;
 276
 277   /* TRUE if every symbol should be reported back via the notice
 278      callback.  */
 279   unsigned int notice_all: 1;
 280
 281   /* TRUE if executable should not contain copy relocs.
 282      Setting this true may result in a non-sharable text segment.  */
 283   unsigned int nocopyreloc: 1;
 284
 285   /* TRUE if the new ELF dynamic tags are enabled. */
 286   unsigned int new_dtags: 1;
 287
 288   /* TRUE if non-PLT relocs should be merged into one reloc section
 289      and sorted so that relocs against the same symbol come together.  */
 290   unsigned int combreloc: 1;
 291
 292   /* TRUE if .eh_frame_hdr section and PT_GNU_EH_FRAME ELF segment
 293      should be created.  */
 294   unsigned int eh_frame_hdr: 1;
 295
 296   /* TRUE if global symbols in discarded sections should be stripped.  */
 297   unsigned int strip_discarded: 1;
 298
 299   /* TRUE if the final relax pass is needed.  */
 300   unsigned int need_relax_finalize: 1;
 301
 302   /* TRUE if generating a position independent executable.  */
 303   unsigned int pie: 1;
 304
 305   /* TRUE if generating an executable, position independent or not.  */
 306   unsigned int executable : 1;
 307
 308   /* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W|PF_X
 309      flags.  */
 310   unsigned int execstack: 1;
 311
 312   /* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W
 313      flags.  */
 314   unsigned int noexecstack: 1;
 315
 316   /* TRUE if PT_GNU_RELRO segment should be created.  */
 317   unsigned int relro: 1;
 318
 319   /* TRUE if we should warn when adding a DT_TEXTREL to a shared object.  */
 320   unsigned int warn_shared_textrel: 1;
 321
 322   /* What to do with unresolved symbols in an object file.
 323      When producing executables the default is GENERATE_ERROR.
 324      When producing shared libraries the default is IGNORE.  The
 325      assumption with shared libraries is that the reference will be
 326      resolved at load/execution time.  */
 327   enum report_method unresolved_syms_in_objects;
 328
 329   /* What to do with unresolved symbols in a shared library.
 330      The same defaults apply.  */
 331   enum report_method unresolved_syms_in_shared_libs;
 332
 333   /* Which symbols to strip.  */
 334   enum bfd_link_strip strip;
 335
 336   /* Which local symbols to discard.  */
 337   enum bfd_link_discard discard;
 338
 339   /* Criteria for skipping symbols when detemining
 340      whether to include an object from an archive. */
 341   enum bfd_link_common_skip_ar_aymbols common_skip_ar_aymbols;
 342
 343   /* Char that may appear as the first char of a symbol, but should be
 344      skipped (like symbol_leading_char) when looking up symbols in
 345      wrap_hash.  Used by PowerPC Linux for 'dot' symbols.  */
 346   char wrap_char;
 347
 348   /* Function callbacks.  */
 349   const struct bfd_link_callbacks *callbacks;
 350
 351   /* Hash table handled by BFD.  */
 352   struct bfd_link_hash_table *hash;
 353
 354   /* Hash table of symbols to keep.  This is NULL unless strip is
 355      strip_some.  */
 356   struct bfd_hash_table *keep_hash;
 357
 358   /* Hash table of symbols to report back via the notice callback.  If
 359      this is NULL, and notice_all is FALSE, then no symbols are
 360      reported back.  */
 361   struct bfd_hash_table *notice_hash;
 362
 363   /* Hash table of symbols which are being wrapped (the --wrap linker
 364      option).  If this is NULL, no symbols are being wrapped.  */
 365   struct bfd_hash_table *wrap_hash;
 366
 367   /* The list of input BFD's involved in the link.  These are chained
 368      together via the link_next field.  */
 369   bfd *input_bfds;
 370
 371   /* If a symbol should be created for each input BFD, this is section
 372      where those symbols should be placed.  It must be a section in
 373      the output BFD.  It may be NULL, in which case no such symbols
 374      will be created.  This is to support CREATE_OBJECT_SYMBOLS in the
 375      linker command language.  */
 376   asection *create_object_symbols_section;
 377
 378   /* List of global symbol names that are starting points for marking
 379      sections against garbage collection.  */
 380   struct bfd_sym_chain *gc_sym_list;
 381
 382   /* If a base output file is wanted, then this points to it */
 383   void *base_file;
 384
 385   /* The function to call when the executable or shared object is
 386      loaded.  */
 387   const char *init_function;
 388
 389   /* The function to call when the executable or shared object is
 390      unloaded.  */
 391   const char *fini_function;
 392
 393   /* Non-zero if auto-import thunks for DATA items in pei386 DLLs
 394      should be generated/linked against.  Set to 1 if this feature
 395      is explicitly requested by the user, -1 if enabled by default.  */
 396   int pei386_auto_import;
 397
 398   /* Non-zero if runtime relocs for DATA items with non-zero addends
 399      in pei386 DLLs should be generated.  Set to 1 if this feature
 400      is explicitly requested by the user, -1 if enabled by default.  */
 401   int pei386_runtime_pseudo_reloc;
 402
 403   /* How many spare .dynamic DT_NULL entries should be added?  */
 404   unsigned int spare_dynamic_tags;
 405
 406   /* May be used to set DT_FLAGS for ELF. */
 407   bfd_vma flags;
 408
 409   /* May be used to set DT_FLAGS_1 for ELF. */
 410   bfd_vma flags_1;
 411
 412   /* Start and end of RELRO region.  */
 413   bfd_vma relro_start, relro_end;
 414 };
 415
 416 /* This structures holds a set of callback functions.  These are
 417    called by the BFD linker routines.  The first argument to each
 418    callback function is the bfd_link_info structure being used.  Each
 419    function returns a boolean value.  If the function returns FALSE,
 420    then the BFD function which called it will return with a failure
 421    indication.  */
 422
 423 struct bfd_link_callbacks
 424 {
 425   /* A function which is called when an object is added from an
 426      archive.  ABFD is the archive element being added.  NAME is the
 427      name of the symbol which caused the archive element to be pulled
 428      in.  */
 429   bfd_boolean (*add_archive_element)
 430     (struct bfd_link_info *, bfd *abfd, const char *name);
 431   /* A function which is called when a symbol is found with multiple
 432      definitions.  NAME is the symbol which is defined multiple times.
 433      OBFD is the old BFD, OSEC is the old section, OVAL is the old
 434      value, NBFD is the new BFD, NSEC is the new section, and NVAL is
 435      the new value.  OBFD may be NULL.  OSEC and NSEC may be
 436      bfd_com_section or bfd_ind_section.  */
 437   bfd_boolean (*multiple_definition)
 438     (struct bfd_link_info *, const char *name,
 439      bfd *obfd, asection *osec, bfd_vma oval,
 440      bfd *nbfd, asection *nsec, bfd_vma nval);
 441   /* A function which is called when a common symbol is defined
 442      multiple times.  NAME is the symbol appearing multiple times.
 443      OBFD is the BFD of the existing symbol; it may be NULL if this is
 444      not known.  OTYPE is the type of the existing symbol, which may
 445      be bfd_link_hash_defined, bfd_link_hash_defweak,
 446      bfd_link_hash_common, or bfd_link_hash_indirect.  If OTYPE is
 447      bfd_link_hash_common, OSIZE is the size of the existing symbol.
 448      NBFD is the BFD of the new symbol.  NTYPE is the type of the new
 449      symbol, one of bfd_link_hash_defined, bfd_link_hash_common, or
 450      bfd_link_hash_indirect.  If NTYPE is bfd_link_hash_common, NSIZE
 451      is the size of the new symbol.  */
 452   bfd_boolean (*multiple_common)
 453     (struct bfd_link_info *, const char *name,
 454      bfd *obfd, enum bfd_link_hash_type otype, bfd_vma osize,
 455      bfd *nbfd, enum bfd_link_hash_type ntype, bfd_vma nsize);
 456   /* A function which is called to add a symbol to a set.  ENTRY is
 457      the link hash table entry for the set itself (e.g.,
 458      __CTOR_LIST__).  RELOC is the relocation to use for an entry in
 459      the set when generating a relocatable file, and is also used to
 460      get the size of the entry when generating an executable file.
 461      ABFD, SEC and VALUE identify the value to add to the set.  */
 462   bfd_boolean (*add_to_set)
 463     (struct bfd_link_info *, struct bfd_link_hash_entry *entry,
 464      bfd_reloc_code_real_type reloc, bfd *abfd, asection *sec, bfd_vma value);
 465   /* A function which is called when the name of a g++ constructor or
 466      destructor is found.  This is only called by some object file
 467      formats.  CONSTRUCTOR is TRUE for a constructor, FALSE for a
 468      destructor.  This will use BFD_RELOC_CTOR when generating a
 469      relocatable file.  NAME is the name of the symbol found.  ABFD,
 470      SECTION and VALUE are the value of the symbol.  */
 471   bfd_boolean (*constructor)
 472     (struct bfd_link_info *, bfd_boolean constructor, const char *name,
 473      bfd *abfd, asection *sec, bfd_vma value);
 474   /* A function which is called to issue a linker warning.  For
 475      example, this is called when there is a reference to a warning
 476      symbol.  WARNING is the warning to be issued.  SYMBOL is the name
 477      of the symbol which triggered the warning; it may be NULL if
 478      there is none.  ABFD, SECTION and ADDRESS identify the location
 479      which trigerred the warning; either ABFD or SECTION or both may
 480      be NULL if the location is not known.  */
 481   bfd_boolean (*warning)
 482     (struct bfd_link_info *, const char *warning, const char *symbol,
 483      bfd *abfd, asection *section, bfd_vma address);
 484   /* A function which is called when a relocation is attempted against
 485      an undefined symbol.  NAME is the symbol which is undefined.
 486      ABFD, SECTION and ADDRESS identify the location from which the
 487      reference is made. FATAL indicates whether an undefined symbol is
 488      a fatal error or not. In some cases SECTION may be NULL.  */
 489   bfd_boolean (*undefined_symbol)
 490     (struct bfd_link_info *, const char *name, bfd *abfd,
 491      asection *section, bfd_vma address, bfd_boolean fatal);
 492   /* A function which is called when a reloc overflow occurs. ENTRY is
 493      the link hash table entry for the symbol the reloc is against.
 494      NAME is the name of the local symbol or section the reloc is
 495      against, RELOC_NAME is the name of the relocation, and ADDEND is
 496      any addend that is used.  ABFD, SECTION and ADDRESS identify the
 497      location at which the overflow occurs; if this is the result of a
 498      bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
 499      ABFD will be NULL.  */
 500   bfd_boolean (*reloc_overflow)
 501     (struct bfd_link_info *, struct bfd_link_hash_entry *entry,
 502      const char *name, const char *reloc_name, bfd_vma addend,
 503      bfd *abfd, asection *section, bfd_vma address);
 504   /* A function which is called when a dangerous reloc is performed.
 505      The canonical example is an a29k IHCONST reloc which does not
 506      follow an IHIHALF reloc.  MESSAGE is an appropriate message.
 507      ABFD, SECTION and ADDRESS identify the location at which the
 508      problem occurred; if this is the result of a
 509      bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
 510      ABFD will be NULL.  */
 511   bfd_boolean (*reloc_dangerous)
 512     (struct bfd_link_info *, const char *message,
 513      bfd *abfd, asection *section, bfd_vma address);
 514   /* A function which is called when a reloc is found to be attached
 515      to a symbol which is not being written out.  NAME is the name of
 516      the symbol.  ABFD, SECTION and ADDRESS identify the location of
 517      the reloc; if this is the result of a
 518      bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
 519      ABFD will be NULL.  */
 520   bfd_boolean (*unattached_reloc)
 521     (struct bfd_link_info *, const char *name,
 522      bfd *abfd, asection *section, bfd_vma address);
 523   /* A function which is called when a symbol in notice_hash is
 524      defined or referenced.  NAME is the symbol.  ABFD, SECTION and
 525      ADDRESS are the value of the symbol.  If SECTION is
 526      bfd_und_section, this is a reference.  */
 527   bfd_boolean (*notice)
 528     (struct bfd_link_info *, const char *name,
 529      bfd *abfd, asection *section, bfd_vma address);
 530 };
 531 \f
 532 /* The linker builds link_order structures which tell the code how to
 533    include input data in the output file.  */
 534
 535 /* These are the types of link_order structures.  */
 536
 537 enum bfd_link_order_type
 538 {
 539   bfd_undefined_link_order,     /* Undefined.  */
 540   bfd_indirect_link_order,      /* Built from a section.  */
 541   bfd_data_link_order,          /* Set to explicit data.  */
 542   bfd_section_reloc_link_order, /* Relocate against a section.  */
 543   bfd_symbol_reloc_link_order   /* Relocate against a symbol.  */
 544 };
 545
 546 /* This is the link_order structure itself.  These form a chain
 547    attached to the section whose contents they are describing.  */
 548
 549 struct bfd_link_order
 550 {
 551   /* Next link_order in chain.  */
 552   struct bfd_link_order *next;
 553   /* Type of link_order.  */
 554   enum bfd_link_order_type type;
 555   /* Offset within output section.  */
 556   bfd_vma offset;
 557   /* Size within output section.  */
 558   bfd_size_type size;
 559   /* Type specific information.  */
 560   union
 561     {
 562       struct
 563         {
 564           /* Section to include.  If this is used, then
 565              section->output_section must be the section the
 566              link_order is attached to, section->output_offset must
 567              equal the link_order offset field, and section->size
 568              must equal the link_order size field.  Maybe these
 569              restrictions should be relaxed someday.  */
 570           asection *section;
 571         } indirect;
 572       struct
 573         {
 574           /* Size of contents, or zero when contents size == size
 575              within output section.
 576              A non-zero value allows filling of the output section
 577              with an arbitrary repeated pattern.  */
 578           unsigned int size;
 579           /* Data to put into file.  */
 580           bfd_byte *contents;
 581         } data;
 582       struct
 583         {
 584           /* Description of reloc to generate.  Used for
 585              bfd_section_reloc_link_order and
 586              bfd_symbol_reloc_link_order.  */
 587           struct bfd_link_order_reloc *p;
 588         } reloc;
 589     } u;
 590 };
 591
 592 /* A linker order of type bfd_section_reloc_link_order or
 593    bfd_symbol_reloc_link_order means to create a reloc against a
 594    section or symbol, respectively.  This is used to implement -Ur to
 595    generate relocs for the constructor tables.  The
 596    bfd_link_order_reloc structure describes the reloc that BFD should
 597    create.  It is similar to a arelent, but I didn't use arelent
 598    because the linker does not know anything about most symbols, and
 599    any asymbol structure it creates will be partially meaningless.
 600    This information could logically be in the bfd_link_order struct,
 601    but I didn't want to waste the space since these types of relocs
 602    are relatively rare.  */
 603
 604 struct bfd_link_order_reloc
 605 {
 606   /* Reloc type.  */
 607   bfd_reloc_code_real_type reloc;
 608
 609   union
 610     {
 611       /* For type bfd_section_reloc_link_order, this is the section
 612          the reloc should be against.  This must be a section in the
 613          output BFD, not any of the input BFDs.  */
 614       asection *section;
 615       /* For type bfd_symbol_reloc_link_order, this is the name of the
 616          symbol the reloc should be against.  */
 617       const char *name;
 618     } u;
 619
 620   /* Addend to use.  The object file should contain zero.  The BFD
 621      backend is responsible for filling in the contents of the object
 622      file correctly.  For some object file formats (e.g., COFF) the
 623      addend must be stored into in the object file, and for some
 624      (e.g., SPARC a.out) it is kept in the reloc.  */
 625   bfd_vma addend;
 626 };
 627
 628 /* Allocate a new link_order for a section.  */
 629 extern struct bfd_link_order *bfd_new_link_order (bfd *, asection *);
 630
 631 /* These structures are used to describe version information for the
 632    ELF linker.  These structures could be manipulated entirely inside
 633    BFD, but it would be a pain.  Instead, the regular linker sets up
 634    these structures, and then passes them into BFD.  */
 635
 636 /* Glob pattern for a version.  */
 637
 638 struct bfd_elf_version_expr
 639 {
 640   /* Next glob pattern for this version.  */
 641   struct bfd_elf_version_expr *next;
 642   /* Glob pattern.  */
 643   const char *pattern;
 644   /* NULL for a glob pattern, otherwise a straight symbol.  */
 645   const char *symbol;
 646   /* Defined by ".symver".  */
 647   unsigned int symver : 1;
 648   /* Defined by version script.  */
 649   unsigned int script : 1;
 650   /* Pattern type.  */
 651 #define BFD_ELF_VERSION_C_TYPE          1
 652 #define BFD_ELF_VERSION_CXX_TYPE        2
 653 #define BFD_ELF_VERSION_JAVA_TYPE       4
 654   unsigned int mask : 3;
 655 };
 656
 657 struct bfd_elf_version_expr_head
 658 {
 659   /* List of all patterns, both wildcards and non-wildcards.  */
 660   struct bfd_elf_version_expr *list;
 661   /* Hash table for non-wildcards.  */
 662   void *htab;
 663   /* Remaining patterns.  */
 664   struct bfd_elf_version_expr *remaining;
 665   /* What kind of pattern types are present in list (bitmask).  */
 666   unsigned int mask;
 667 };
 668
 669 /* Version dependencies.  */
 670
 671 struct bfd_elf_version_deps
 672 {
 673   /* Next dependency for this version.  */
 674   struct bfd_elf_version_deps *next;
 675   /* The version which this version depends upon.  */
 676   struct bfd_elf_version_tree *version_needed;
 677 };
 678
 679 /* A node in the version tree.  */
 680
 681 struct bfd_elf_version_tree
 682 {
 683   /* Next version.  */
 684   struct bfd_elf_version_tree *next;
 685   /* Name of this version.  */
 686   const char *name;
 687   /* Version number.  */
 688   unsigned int vernum;
 689   /* Regular expressions for global symbols in this version.  */
 690   struct bfd_elf_version_expr_head globals;
 691   /* Regular expressions for local symbols in this version.  */
 692   struct bfd_elf_version_expr_head locals;
 693   /* List of versions which this version depends upon.  */
 694   struct bfd_elf_version_deps *deps;
 695   /* Index of the version name.  This is used within BFD.  */
 696   unsigned int name_indx;
 697   /* Whether this version tree was used.  This is used within BFD.  */
 698   int used;
 699   /* Matching hook.  */
 700   struct bfd_elf_version_expr *(*match)
 701     (struct bfd_elf_version_expr_head *head,
 702      struct bfd_elf_version_expr *prev, const char *sym);
 703 };
 704
 705 #endif