include/bfdlink.h

   1 /* bfdlink.h -- header file for BFD link routines
   2    Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
   3    2003, 2004, 2005 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., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, 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           bfd *weak;            /* BFD weak symbol was found in.  */
 117         } undef;
 118       /* bfd_link_hash_defined, bfd_link_hash_defweak.  */
 119       struct
 120         {
 121           struct bfd_link_hash_entry *next;
 122           asection *section;    /* Symbol section.  */
 123           bfd_vma value;        /* Symbol value.  */
 124         } def;
 125       /* bfd_link_hash_indirect, bfd_link_hash_warning.  */
 126       struct
 127         {
 128           struct bfd_link_hash_entry *next;
 129           struct bfd_link_hash_entry *link;     /* Real symbol.  */
 130           const char *warning;  /* Warning (bfd_link_hash_warning only).  */
 131         } i;
 132       /* bfd_link_hash_common.  */
 133       struct
 134         {
 135           struct bfd_link_hash_entry *next;
 136           /* The linker needs to know three things about common
 137              symbols: the size, the alignment, and the section in
 138              which the symbol should be placed.  We store the size
 139              here, and we allocate a small structure to hold the
 140              section and the alignment.  The alignment is stored as a
 141              power of two.  We don't store all the information
 142              directly because we don't want to increase the size of
 143              the union; this structure is a major space user in the
 144              linker.  */
 145           struct bfd_link_hash_common_entry
 146             {
 147               unsigned int alignment_power;     /* Alignment.  */
 148               asection *section;                /* Symbol section.  */
 149             } *p;
 150           bfd_size_type size;   /* Common symbol size.  */
 151         } c;
 152     } u;
 153 };
 154
 155 /* This is the link hash table.  It is a derived class of
 156    bfd_hash_table.  */
 157
 158 struct bfd_link_hash_table
 159 {
 160   /* The hash table itself.  */
 161   struct bfd_hash_table table;
 162   /* The back end which created this hash table.  This indicates the
 163      type of the entries in the hash table, which is sometimes
 164      important information when linking object files of different
 165      types together.  */
 166   const bfd_target *creator;
 167   /* A linked list of undefined and common symbols, linked through the
 168      next field in the bfd_link_hash_entry structure.  */
 169   struct bfd_link_hash_entry *undefs;
 170   /* Entries are added to the tail of the undefs list.  */
 171   struct bfd_link_hash_entry *undefs_tail;
 172   /* The type of the link hash table.  */
 173   enum bfd_link_hash_table_type type;
 174 };
 175
 176 /* Look up an entry in a link hash table.  If FOLLOW is TRUE, this
 177    follows bfd_link_hash_indirect and bfd_link_hash_warning links to
 178    the real symbol.  */
 179 extern struct bfd_link_hash_entry *bfd_link_hash_lookup
 180   (struct bfd_link_hash_table *, const char *, bfd_boolean create,
 181    bfd_boolean copy, bfd_boolean follow);
 182
 183 /* Look up an entry in the main linker hash table if the symbol might
 184    be wrapped.  This should only be used for references to an
 185    undefined symbol, not for definitions of a symbol.  */
 186
 187 extern struct bfd_link_hash_entry *bfd_wrapped_link_hash_lookup
 188   (bfd *, struct bfd_link_info *, const char *, bfd_boolean,
 189    bfd_boolean, bfd_boolean);
 190
 191 /* Traverse a link hash table.  */
 192 extern void bfd_link_hash_traverse
 193   (struct bfd_link_hash_table *,
 194     bfd_boolean (*) (struct bfd_link_hash_entry *, void *),
 195     void *);
 196
 197 /* Add an entry to the undefs list.  */
 198 extern void bfd_link_add_undef
 199   (struct bfd_link_hash_table *, struct bfd_link_hash_entry *);
 200
 201 /* Remove symbols from the undefs list that don't belong there.  */
 202 extern void bfd_link_repair_undef_list
 203   (struct bfd_link_hash_table *table);
 204
 205 struct bfd_sym_chain
 206 {
 207   struct bfd_sym_chain *next;
 208   const char *name;
 209 };
 210 \f
 211 /* How to handle unresolved symbols.
 212    There are four possibilities which are enumerated below:  */
 213 enum report_method
 214 {
 215   /* This is the initial value when then link_info structure is created.
 216      It allows the various stages of the linker to determine whether they
 217      allowed to set the value.  */
 218   RM_NOT_YET_SET = 0,
 219   RM_IGNORE,
 220   RM_GENERATE_WARNING,
 221   RM_GENERATE_ERROR
 222 };
 223
 224 /* This structure holds all the information needed to communicate
 225    between BFD and the linker when doing a link.  */
 226
 227 struct bfd_link_info
 228 {
 229   /* TRUE if BFD should generate a relocatable object file.  */
 230   unsigned int relocatable: 1;
 231
 232   /* TRUE if BFD should generate relocation information in the final
 233      executable.  */
 234   unsigned int emitrelocations: 1;
 235
 236   /* TRUE if BFD should generate a "task linked" object file,
 237      similar to relocatable but also with globals converted to
 238      statics.  */
 239   unsigned int task_link: 1;
 240
 241   /* TRUE if BFD should generate a shared object.  */
 242   unsigned int shared: 1;
 243
 244   /* TRUE if BFD should pre-bind symbols in a shared object.  */
 245   unsigned int symbolic: 1;
 246
 247   /* TRUE if BFD should export all symbols in the dynamic symbol table
 248      of an executable, rather than only those used.  */
 249   unsigned int export_dynamic: 1;
 250
 251   /* TRUE if shared objects should be linked directly, not shared.  */
 252   unsigned int static_link: 1;
 253
 254   /* TRUE if the output file should be in a traditional format.  This
 255      is equivalent to the setting of the BFD_TRADITIONAL_FORMAT flag
 256      on the output file, but may be checked when reading the input
 257      files.  */
 258   unsigned int traditional_format: 1;
 259
 260   /* TRUE if we want to produced optimized output files.  This might
 261      need much more time and therefore must be explicitly selected.  */
 262   unsigned int optimize: 1;
 263
 264   /* TRUE if ok to have multiple definition.  */
 265   unsigned int allow_multiple_definition: 1;
 266
 267   /* TRUE if ok to have version with no definition.  */
 268   unsigned int allow_undefined_version: 1;
 269
 270   /* TRUE if a default symbol version should be created and used for
 271      exported symbols.  */
 272   unsigned int create_default_symver: 1;
 273
 274   /* TRUE if a default symbol version should be created and used for
 275      imported symbols.  */
 276   unsigned int default_imported_symver: 1;
 277
 278   /* TRUE if symbols should be retained in memory, FALSE if they
 279      should be freed and reread.  */
 280   unsigned int keep_memory: 1;
 281
 282   /* TRUE if every symbol should be reported back via the notice
 283      callback.  */
 284   unsigned int notice_all: 1;
 285
 286   /* TRUE if executable should not contain copy relocs.
 287      Setting this true may result in a non-sharable text segment.  */
 288   unsigned int nocopyreloc: 1;
 289
 290   /* TRUE if the new ELF dynamic tags are enabled. */
 291   unsigned int new_dtags: 1;
 292
 293   /* TRUE if non-PLT relocs should be merged into one reloc section
 294      and sorted so that relocs against the same symbol come together.  */
 295   unsigned int combreloc: 1;
 296
 297   /* TRUE if .eh_frame_hdr section and PT_GNU_EH_FRAME ELF segment
 298      should be created.  */
 299   unsigned int eh_frame_hdr: 1;
 300
 301   /* TRUE if global symbols in discarded sections should be stripped.  */
 302   unsigned int strip_discarded: 1;
 303
 304   /* TRUE if the final relax pass is needed.  */
 305   unsigned int need_relax_finalize: 1;
 306
 307   /* TRUE if generating a position independent executable.  */
 308   unsigned int pie: 1;
 309
 310   /* TRUE if generating an executable, position independent or not.  */
 311   unsigned int executable : 1;
 312
 313   /* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W|PF_X
 314      flags.  */
 315   unsigned int execstack: 1;
 316
 317   /* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W
 318      flags.  */
 319   unsigned int noexecstack: 1;
 320
 321   /* TRUE if PT_GNU_RELRO segment should be created.  */
 322   unsigned int relro: 1;
 323
 324   /* TRUE if we should warn when adding a DT_TEXTREL to a shared object.  */
 325   unsigned int warn_shared_textrel: 1;
 326
 327   /* TRUE if unreferenced sections should be removed.  */
 328   unsigned int gc_sections: 1;
 329
 330   /* What to do with unresolved symbols in an object file.
 331      When producing executables the default is GENERATE_ERROR.
 332      When producing shared libraries the default is IGNORE.  The
 333      assumption with shared libraries is that the reference will be
 334      resolved at load/execution time.  */
 335   enum report_method unresolved_syms_in_objects;
 336
 337   /* What to do with unresolved symbols in a shared library.
 338      The same defaults apply.  */
 339   enum report_method unresolved_syms_in_shared_libs;
 340
 341   /* Which symbols to strip.  */
 342   enum bfd_link_strip strip;
 343
 344   /* Which local symbols to discard.  */
 345   enum bfd_link_discard discard;
 346
 347   /* Criteria for skipping symbols when detemining
 348      whether to include an object from an archive. */
 349   enum bfd_link_common_skip_ar_aymbols common_skip_ar_aymbols;
 350
 351   /* Char that may appear as the first char of a symbol, but should be
 352      skipped (like symbol_leading_char) when looking up symbols in
 353      wrap_hash.  Used by PowerPC Linux for 'dot' symbols.  */
 354   char wrap_char;
 355
 356   /* Function callbacks.  */
 357   const struct bfd_link_callbacks *callbacks;
 358
 359   /* Hash table handled by BFD.  */
 360   struct bfd_link_hash_table *hash;
 361
 362   /* Hash table of symbols to keep.  This is NULL unless strip is
 363      strip_some.  */
 364   struct bfd_hash_table *keep_hash;
 365
 366   /* Hash table of symbols to report back via the notice callback.  If
 367      this is NULL, and notice_all is FALSE, then no symbols are
 368      reported back.  */
 369   struct bfd_hash_table *notice_hash;
 370
 371   /* Hash table of symbols which are being wrapped (the --wrap linker
 372      option).  If this is NULL, no symbols are being wrapped.  */
 373   struct bfd_hash_table *wrap_hash;
 374
 375   /* The list of input BFD's involved in the link.  These are chained
 376      together via the link_next field.  */
 377   bfd *input_bfds;
 378
 379   /* If a symbol should be created for each input BFD, this is section
 380      where those symbols should be placed.  It must be a section in
 381      the output BFD.  It may be NULL, in which case no such symbols
 382      will be created.  This is to support CREATE_OBJECT_SYMBOLS in the
 383      linker command language.  */
 384   asection *create_object_symbols_section;
 385
 386   /* List of global symbol names that are starting points for marking
 387      sections against garbage collection.  */
 388   struct bfd_sym_chain *gc_sym_list;
 389
 390   /* If a base output file is wanted, then this points to it */
 391   void *base_file;
 392
 393   /* The function to call when the executable or shared object is
 394      loaded.  */
 395   const char *init_function;
 396
 397   /* The function to call when the executable or shared object is
 398      unloaded.  */
 399   const char *fini_function;
 400
 401   /* Non-zero if auto-import thunks for DATA items in pei386 DLLs
 402      should be generated/linked against.  Set to 1 if this feature
 403      is explicitly requested by the user, -1 if enabled by default.  */
 404   int pei386_auto_import;
 405
 406   /* Non-zero if runtime relocs for DATA items with non-zero addends
 407      in pei386 DLLs should be generated.  Set to 1 if this feature
 408      is explicitly requested by the user, -1 if enabled by default.  */
 409   int pei386_runtime_pseudo_reloc;
 410
 411   /* How many spare .dynamic DT_NULL entries should be added?  */
 412   unsigned int spare_dynamic_tags;
 413
 414   /* May be used to set DT_FLAGS for ELF. */
 415   bfd_vma flags;
 416
 417   /* May be used to set DT_FLAGS_1 for ELF. */
 418   bfd_vma flags_1;
 419
 420   /* Start and end of RELRO region.  */
 421   bfd_vma relro_start, relro_end;
 422 };
 423
 424 /* This structures holds a set of callback functions.  These are
 425    called by the BFD linker routines.  The first argument to each
 426    callback function is the bfd_link_info structure being used.  Each
 427    function returns a boolean value.  If the function returns FALSE,
 428    then the BFD function which called it will return with a failure
 429    indication.  */
 430
 431 struct bfd_link_callbacks
 432 {
 433   /* A function which is called when an object is added from an
 434      archive.  ABFD is the archive element being added.  NAME is the
 435      name of the symbol which caused the archive element to be pulled
 436      in.  */
 437   bfd_boolean (*add_archive_element)
 438     (struct bfd_link_info *, bfd *abfd, const char *name);
 439   /* A function which is called when a symbol is found with multiple
 440      definitions.  NAME is the symbol which is defined multiple times.
 441      OBFD is the old BFD, OSEC is the old section, OVAL is the old
 442      value, NBFD is the new BFD, NSEC is the new section, and NVAL is
 443      the new value.  OBFD may be NULL.  OSEC and NSEC may be
 444      bfd_com_section or bfd_ind_section.  */
 445   bfd_boolean (*multiple_definition)
 446     (struct bfd_link_info *, const char *name,
 447      bfd *obfd, asection *osec, bfd_vma oval,
 448      bfd *nbfd, asection *nsec, bfd_vma nval);
 449   /* A function which is called when a common symbol is defined
 450      multiple times.  NAME is the symbol appearing multiple times.
 451      OBFD is the BFD of the existing symbol; it may be NULL if this is
 452      not known.  OTYPE is the type of the existing symbol, which may
 453      be bfd_link_hash_defined, bfd_link_hash_defweak,
 454      bfd_link_hash_common, or bfd_link_hash_indirect.  If OTYPE is
 455      bfd_link_hash_common, OSIZE is the size of the existing symbol.
 456      NBFD is the BFD of the new symbol.  NTYPE is the type of the new
 457      symbol, one of bfd_link_hash_defined, bfd_link_hash_common, or
 458      bfd_link_hash_indirect.  If NTYPE is bfd_link_hash_common, NSIZE
 459      is the size of the new symbol.  */
 460   bfd_boolean (*multiple_common)
 461     (struct bfd_link_info *, const char *name,
 462      bfd *obfd, enum bfd_link_hash_type otype, bfd_vma osize,
 463      bfd *nbfd, enum bfd_link_hash_type ntype, bfd_vma nsize);
 464   /* A function which is called to add a symbol to a set.  ENTRY is
 465      the link hash table entry for the set itself (e.g.,
 466      __CTOR_LIST__).  RELOC is the relocation to use for an entry in
 467      the set when generating a relocatable file, and is also used to
 468      get the size of the entry when generating an executable file.
 469      ABFD, SEC and VALUE identify the value to add to the set.  */
 470   bfd_boolean (*add_to_set)
 471     (struct bfd_link_info *, struct bfd_link_hash_entry *entry,
 472      bfd_reloc_code_real_type reloc, bfd *abfd, asection *sec, bfd_vma value);
 473   /* A function which is called when the name of a g++ constructor or
 474      destructor is found.  This is only called by some object file
 475      formats.  CONSTRUCTOR is TRUE for a constructor, FALSE for a
 476      destructor.  This will use BFD_RELOC_CTOR when generating a
 477      relocatable file.  NAME is the name of the symbol found.  ABFD,
 478      SECTION and VALUE are the value of the symbol.  */
 479   bfd_boolean (*constructor)
 480     (struct bfd_link_info *, bfd_boolean constructor, const char *name,
 481      bfd *abfd, asection *sec, bfd_vma value);
 482   /* A function which is called to issue a linker warning.  For
 483      example, this is called when there is a reference to a warning
 484      symbol.  WARNING is the warning to be issued.  SYMBOL is the name
 485      of the symbol which triggered the warning; it may be NULL if
 486      there is none.  ABFD, SECTION and ADDRESS identify the location
 487      which trigerred the warning; either ABFD or SECTION or both may
 488      be NULL if the location is not known.  */
 489   bfd_boolean (*warning)
 490     (struct bfd_link_info *, const char *warning, const char *symbol,
 491      bfd *abfd, asection *section, bfd_vma address);
 492   /* A function which is called when a relocation is attempted against
 493      an undefined symbol.  NAME is the symbol which is undefined.
 494      ABFD, SECTION and ADDRESS identify the location from which the
 495      reference is made. FATAL indicates whether an undefined symbol is
 496      a fatal error or not. In some cases SECTION may be NULL.  */
 497   bfd_boolean (*undefined_symbol)
 498     (struct bfd_link_info *, const char *name, bfd *abfd,
 499      asection *section, bfd_vma address, bfd_boolean fatal);
 500   /* A function which is called when a reloc overflow occurs. ENTRY is
 501      the link hash table entry for the symbol the reloc is against.
 502      NAME is the name of the local symbol or section the reloc is
 503      against, RELOC_NAME is the name of the relocation, and ADDEND is
 504      any addend that is used.  ABFD, SECTION and ADDRESS identify the
 505      location at which the overflow occurs; if this is the result of a
 506      bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
 507      ABFD will be NULL.  */
 508   bfd_boolean (*reloc_overflow)
 509     (struct bfd_link_info *, struct bfd_link_hash_entry *entry,
 510      const char *name, const char *reloc_name, bfd_vma addend,
 511      bfd *abfd, asection *section, bfd_vma address);
 512   /* A function which is called when a dangerous reloc is performed.
 513      The canonical example is an a29k IHCONST reloc which does not
 514      follow an IHIHALF reloc.  MESSAGE is an appropriate message.
 515      ABFD, SECTION and ADDRESS identify the location at which the
 516      problem occurred; if this is the result of a
 517      bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
 518      ABFD will be NULL.  */
 519   bfd_boolean (*reloc_dangerous)
 520     (struct bfd_link_info *, const char *message,
 521      bfd *abfd, asection *section, bfd_vma address);
 522   /* A function which is called when a reloc is found to be attached
 523      to a symbol which is not being written out.  NAME is the name of
 524      the symbol.  ABFD, SECTION and ADDRESS identify the location of
 525      the reloc; if this is the result of a
 526      bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
 527      ABFD will be NULL.  */
 528   bfd_boolean (*unattached_reloc)
 529     (struct bfd_link_info *, const char *name,
 530      bfd *abfd, asection *section, bfd_vma address);
 531   /* A function which is called when a symbol in notice_hash is
 532      defined or referenced.  NAME is the symbol.  ABFD, SECTION and
 533      ADDRESS are the value of the symbol.  If SECTION is
 534      bfd_und_section, this is a reference.  */
 535   bfd_boolean (*notice)
 536     (struct bfd_link_info *, const char *name,
 537      bfd *abfd, asection *section, bfd_vma address);
 538 };
 539 \f
 540 /* The linker builds link_order structures which tell the code how to
 541    include input data in the output file.  */
 542
 543 /* These are the types of link_order structures.  */
 544
 545 enum bfd_link_order_type
 546 {
 547   bfd_undefined_link_order,     /* Undefined.  */
 548   bfd_indirect_link_order,      /* Built from a section.  */
 549   bfd_data_link_order,          /* Set to explicit data.  */
 550   bfd_section_reloc_link_order, /* Relocate against a section.  */
 551   bfd_symbol_reloc_link_order   /* Relocate against a symbol.  */
 552 };
 553
 554 /* This is the link_order structure itself.  These form a chain
 555    attached to the section whose contents they are describing.  */
 556
 557 struct bfd_link_order
 558 {
 559   /* Next link_order in chain.  */
 560   struct bfd_link_order *next;
 561   /* Type of link_order.  */
 562   enum bfd_link_order_type type;
 563   /* Offset within output section.  */
 564   bfd_vma offset;
 565   /* Size within output section.  */
 566   bfd_size_type size;
 567   /* Type specific information.  */
 568   union
 569     {
 570       struct
 571         {
 572           /* Section to include.  If this is used, then
 573              section->output_section must be the section the
 574              link_order is attached to, section->output_offset must
 575              equal the link_order offset field, and section->size
 576              must equal the link_order size field.  Maybe these
 577              restrictions should be relaxed someday.  */
 578           asection *section;
 579         } indirect;
 580       struct
 581         {
 582           /* Size of contents, or zero when contents size == size
 583              within output section.
 584              A non-zero value allows filling of the output section
 585              with an arbitrary repeated pattern.  */
 586           unsigned int size;
 587           /* Data to put into file.  */
 588           bfd_byte *contents;
 589         } data;
 590       struct
 591         {
 592           /* Description of reloc to generate.  Used for
 593              bfd_section_reloc_link_order and
 594              bfd_symbol_reloc_link_order.  */
 595           struct bfd_link_order_reloc *p;
 596         } reloc;
 597     } u;
 598 };
 599
 600 /* A linker order of type bfd_section_reloc_link_order or
 601    bfd_symbol_reloc_link_order means to create a reloc against a
 602    section or symbol, respectively.  This is used to implement -Ur to
 603    generate relocs for the constructor tables.  The
 604    bfd_link_order_reloc structure describes the reloc that BFD should
 605    create.  It is similar to a arelent, but I didn't use arelent
 606    because the linker does not know anything about most symbols, and
 607    any asymbol structure it creates will be partially meaningless.
 608    This information could logically be in the bfd_link_order struct,
 609    but I didn't want to waste the space since these types of relocs
 610    are relatively rare.  */
 611
 612 struct bfd_link_order_reloc
 613 {
 614   /* Reloc type.  */
 615   bfd_reloc_code_real_type reloc;
 616
 617   union
 618     {
 619       /* For type bfd_section_reloc_link_order, this is the section
 620          the reloc should be against.  This must be a section in the
 621          output BFD, not any of the input BFDs.  */
 622       asection *section;
 623       /* For type bfd_symbol_reloc_link_order, this is the name of the
 624          symbol the reloc should be against.  */
 625       const char *name;
 626     } u;
 627
 628   /* Addend to use.  The object file should contain zero.  The BFD
 629      backend is responsible for filling in the contents of the object
 630      file correctly.  For some object file formats (e.g., COFF) the
 631      addend must be stored into in the object file, and for some
 632      (e.g., SPARC a.out) it is kept in the reloc.  */
 633   bfd_vma addend;
 634 };
 635
 636 /* Allocate a new link_order for a section.  */
 637 extern struct bfd_link_order *bfd_new_link_order (bfd *, asection *);
 638
 639 /* These structures are used to describe version information for the
 640    ELF linker.  These structures could be manipulated entirely inside
 641    BFD, but it would be a pain.  Instead, the regular linker sets up
 642    these structures, and then passes them into BFD.  */
 643
 644 /* Glob pattern for a version.  */
 645
 646 struct bfd_elf_version_expr
 647 {
 648   /* Next glob pattern for this version.  */
 649   struct bfd_elf_version_expr *next;
 650   /* Glob pattern.  */
 651   const char *pattern;
 652   /* NULL for a glob pattern, otherwise a straight symbol.  */
 653   const char *symbol;
 654   /* Defined by ".symver".  */
 655   unsigned int symver : 1;
 656   /* Defined by version script.  */
 657   unsigned int script : 1;
 658   /* Pattern type.  */
 659 #define BFD_ELF_VERSION_C_TYPE          1
 660 #define BFD_ELF_VERSION_CXX_TYPE        2
 661 #define BFD_ELF_VERSION_JAVA_TYPE       4
 662   unsigned int mask : 3;
 663 };
 664
 665 struct bfd_elf_version_expr_head
 666 {
 667   /* List of all patterns, both wildcards and non-wildcards.  */
 668   struct bfd_elf_version_expr *list;
 669   /* Hash table for non-wildcards.  */
 670   void *htab;
 671   /* Remaining patterns.  */
 672   struct bfd_elf_version_expr *remaining;
 673   /* What kind of pattern types are present in list (bitmask).  */
 674   unsigned int mask;
 675 };
 676
 677 /* Version dependencies.  */
 678
 679 struct bfd_elf_version_deps
 680 {
 681   /* Next dependency for this version.  */
 682   struct bfd_elf_version_deps *next;
 683   /* The version which this version depends upon.  */
 684   struct bfd_elf_version_tree *version_needed;
 685 };
 686
 687 /* A node in the version tree.  */
 688
 689 struct bfd_elf_version_tree
 690 {
 691   /* Next version.  */
 692   struct bfd_elf_version_tree *next;
 693   /* Name of this version.  */
 694   const char *name;
 695   /* Version number.  */
 696   unsigned int vernum;
 697   /* Regular expressions for global symbols in this version.  */
 698   struct bfd_elf_version_expr_head globals;
 699   /* Regular expressions for local symbols in this version.  */
 700   struct bfd_elf_version_expr_head locals;
 701   /* List of versions which this version depends upon.  */
 702   struct bfd_elf_version_deps *deps;
 703   /* Index of the version name.  This is used within BFD.  */
 704   unsigned int name_indx;
 705   /* Whether this version tree was used.  This is used within BFD.  */
 706   int used;
 707   /* Matching hook.  */
 708   struct bfd_elf_version_expr *(*match)
 709     (struct bfd_elf_version_expr_head *head,
 710      struct bfd_elf_version_expr *prev, const char *sym);
 711 };
 712
 713 #endif