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., 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           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   /* What to do with unresolved symbols in an object file.
 328      When producing executables the default is GENERATE_ERROR.
 329      When producing shared libraries the default is IGNORE.  The
 330      assumption with shared libraries is that the reference will be
 331      resolved at load/execution time.  */
 332   enum report_method unresolved_syms_in_objects;
 333
 334   /* What to do with unresolved symbols in a shared library.
 335      The same defaults apply.  */
 336   enum report_method unresolved_syms_in_shared_libs;
 337
 338   /* Which symbols to strip.  */
 339   enum bfd_link_strip strip;
 340
 341   /* Which local symbols to discard.  */
 342   enum bfd_link_discard discard;
 343
 344   /* Criteria for skipping symbols when detemining
 345      whether to include an object from an archive. */
 346   enum bfd_link_common_skip_ar_aymbols common_skip_ar_aymbols;
 347
 348   /* Char that may appear as the first char of a symbol, but should be
 349      skipped (like symbol_leading_char) when looking up symbols in
 350      wrap_hash.  Used by PowerPC Linux for 'dot' symbols.  */
 351   char wrap_char;
 352
 353   /* Function callbacks.  */
 354   const struct bfd_link_callbacks *callbacks;
 355
 356   /* Hash table handled by BFD.  */
 357   struct bfd_link_hash_table *hash;
 358
 359   /* Hash table of symbols to keep.  This is NULL unless strip is
 360      strip_some.  */
 361   struct bfd_hash_table *keep_hash;
 362
 363   /* Hash table of symbols to report back via the notice callback.  If
 364      this is NULL, and notice_all is FALSE, then no symbols are
 365      reported back.  */
 366   struct bfd_hash_table *notice_hash;
 367
 368   /* Hash table of symbols which are being wrapped (the --wrap linker
 369      option).  If this is NULL, no symbols are being wrapped.  */
 370   struct bfd_hash_table *wrap_hash;
 371
 372   /* The list of input BFD's involved in the link.  These are chained
 373      together via the link_next field.  */
 374   bfd *input_bfds;
 375
 376   /* If a symbol should be created for each input BFD, this is section
 377      where those symbols should be placed.  It must be a section in
 378      the output BFD.  It may be NULL, in which case no such symbols
 379      will be created.  This is to support CREATE_OBJECT_SYMBOLS in the
 380      linker command language.  */
 381   asection *create_object_symbols_section;
 382
 383   /* List of global symbol names that are starting points for marking
 384      sections against garbage collection.  */
 385   struct bfd_sym_chain *gc_sym_list;
 386
 387   /* If a base output file is wanted, then this points to it */
 388   void *base_file;
 389
 390   /* The function to call when the executable or shared object is
 391      loaded.  */
 392   const char *init_function;
 393
 394   /* The function to call when the executable or shared object is
 395      unloaded.  */
 396   const char *fini_function;
 397
 398   /* Non-zero if auto-import thunks for DATA items in pei386 DLLs
 399      should be generated/linked against.  Set to 1 if this feature
 400      is explicitly requested by the user, -1 if enabled by default.  */
 401   int pei386_auto_import;
 402
 403   /* Non-zero if runtime relocs for DATA items with non-zero addends
 404      in pei386 DLLs should be generated.  Set to 1 if this feature
 405      is explicitly requested by the user, -1 if enabled by default.  */
 406   int pei386_runtime_pseudo_reloc;
 407
 408   /* How many spare .dynamic DT_NULL entries should be added?  */
 409   unsigned int spare_dynamic_tags;
 410
 411   /* May be used to set DT_FLAGS for ELF. */
 412   bfd_vma flags;
 413
 414   /* May be used to set DT_FLAGS_1 for ELF. */
 415   bfd_vma flags_1;
 416
 417   /* Start and end of RELRO region.  */
 418   bfd_vma relro_start, relro_end;
 419 };
 420
 421 /* This structures holds a set of callback functions.  These are
 422    called by the BFD linker routines.  The first argument to each
 423    callback function is the bfd_link_info structure being used.  Each
 424    function returns a boolean value.  If the function returns FALSE,
 425    then the BFD function which called it will return with a failure
 426    indication.  */
 427
 428 struct bfd_link_callbacks
 429 {
 430   /* A function which is called when an object is added from an
 431      archive.  ABFD is the archive element being added.  NAME is the
 432      name of the symbol which caused the archive element to be pulled
 433      in.  */
 434   bfd_boolean (*add_archive_element)
 435     (struct bfd_link_info *, bfd *abfd, const char *name);
 436   /* A function which is called when a symbol is found with multiple
 437      definitions.  NAME is the symbol which is defined multiple times.
 438      OBFD is the old BFD, OSEC is the old section, OVAL is the old
 439      value, NBFD is the new BFD, NSEC is the new section, and NVAL is
 440      the new value.  OBFD may be NULL.  OSEC and NSEC may be
 441      bfd_com_section or bfd_ind_section.  */
 442   bfd_boolean (*multiple_definition)
 443     (struct bfd_link_info *, const char *name,
 444      bfd *obfd, asection *osec, bfd_vma oval,
 445      bfd *nbfd, asection *nsec, bfd_vma nval);
 446   /* A function which is called when a common symbol is defined
 447      multiple times.  NAME is the symbol appearing multiple times.
 448      OBFD is the BFD of the existing symbol; it may be NULL if this is
 449      not known.  OTYPE is the type of the existing symbol, which may
 450      be bfd_link_hash_defined, bfd_link_hash_defweak,
 451      bfd_link_hash_common, or bfd_link_hash_indirect.  If OTYPE is
 452      bfd_link_hash_common, OSIZE is the size of the existing symbol.
 453      NBFD is the BFD of the new symbol.  NTYPE is the type of the new
 454      symbol, one of bfd_link_hash_defined, bfd_link_hash_common, or
 455      bfd_link_hash_indirect.  If NTYPE is bfd_link_hash_common, NSIZE
 456      is the size of the new symbol.  */
 457   bfd_boolean (*multiple_common)
 458     (struct bfd_link_info *, const char *name,
 459      bfd *obfd, enum bfd_link_hash_type otype, bfd_vma osize,
 460      bfd *nbfd, enum bfd_link_hash_type ntype, bfd_vma nsize);
 461   /* A function which is called to add a symbol to a set.  ENTRY is
 462      the link hash table entry for the set itself (e.g.,
 463      __CTOR_LIST__).  RELOC is the relocation to use for an entry in
 464      the set when generating a relocatable file, and is also used to
 465      get the size of the entry when generating an executable file.
 466      ABFD, SEC and VALUE identify the value to add to the set.  */
 467   bfd_boolean (*add_to_set)
 468     (struct bfd_link_info *, struct bfd_link_hash_entry *entry,
 469      bfd_reloc_code_real_type reloc, bfd *abfd, asection *sec, bfd_vma value);
 470   /* A function which is called when the name of a g++ constructor or
 471      destructor is found.  This is only called by some object file
 472      formats.  CONSTRUCTOR is TRUE for a constructor, FALSE for a
 473      destructor.  This will use BFD_RELOC_CTOR when generating a
 474      relocatable file.  NAME is the name of the symbol found.  ABFD,
 475      SECTION and VALUE are the value of the symbol.  */
 476   bfd_boolean (*constructor)
 477     (struct bfd_link_info *, bfd_boolean constructor, const char *name,
 478      bfd *abfd, asection *sec, bfd_vma value);
 479   /* A function which is called to issue a linker warning.  For
 480      example, this is called when there is a reference to a warning
 481      symbol.  WARNING is the warning to be issued.  SYMBOL is the name
 482      of the symbol which triggered the warning; it may be NULL if
 483      there is none.  ABFD, SECTION and ADDRESS identify the location
 484      which trigerred the warning; either ABFD or SECTION or both may
 485      be NULL if the location is not known.  */
 486   bfd_boolean (*warning)
 487     (struct bfd_link_info *, const char *warning, const char *symbol,
 488      bfd *abfd, asection *section, bfd_vma address);
 489   /* A function which is called when a relocation is attempted against
 490      an undefined symbol.  NAME is the symbol which is undefined.
 491      ABFD, SECTION and ADDRESS identify the location from which the
 492      reference is made. FATAL indicates whether an undefined symbol is
 493      a fatal error or not. In some cases SECTION may be NULL.  */
 494   bfd_boolean (*undefined_symbol)
 495     (struct bfd_link_info *, const char *name, bfd *abfd,
 496      asection *section, bfd_vma address, bfd_boolean fatal);
 497   /* A function which is called when a reloc overflow occurs. ENTRY is
 498      the link hash table entry for the symbol the reloc is against.
 499      NAME is the name of the local symbol or section the reloc is
 500      against, RELOC_NAME is the name of the relocation, and ADDEND is
 501      any addend that is used.  ABFD, SECTION and ADDRESS identify the
 502      location at which the overflow occurs; if this is the result of a
 503      bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
 504      ABFD will be NULL.  */
 505   bfd_boolean (*reloc_overflow)
 506     (struct bfd_link_info *, struct bfd_link_hash_entry *entry,
 507      const char *name, const char *reloc_name, bfd_vma addend,
 508      bfd *abfd, asection *section, bfd_vma address);
 509   /* A function which is called when a dangerous reloc is performed.
 510      The canonical example is an a29k IHCONST reloc which does not
 511      follow an IHIHALF reloc.  MESSAGE is an appropriate message.
 512      ABFD, SECTION and ADDRESS identify the location at which the
 513      problem occurred; if this is the result of a
 514      bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
 515      ABFD will be NULL.  */
 516   bfd_boolean (*reloc_dangerous)
 517     (struct bfd_link_info *, const char *message,
 518      bfd *abfd, asection *section, bfd_vma address);
 519   /* A function which is called when a reloc is found to be attached
 520      to a symbol which is not being written out.  NAME is the name of
 521      the symbol.  ABFD, SECTION and ADDRESS identify the location of
 522      the reloc; if this is the result of a
 523      bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
 524      ABFD will be NULL.  */
 525   bfd_boolean (*unattached_reloc)
 526     (struct bfd_link_info *, const char *name,
 527      bfd *abfd, asection *section, bfd_vma address);
 528   /* A function which is called when a symbol in notice_hash is
 529      defined or referenced.  NAME is the symbol.  ABFD, SECTION and
 530      ADDRESS are the value of the symbol.  If SECTION is
 531      bfd_und_section, this is a reference.  */
 532   bfd_boolean (*notice)
 533     (struct bfd_link_info *, const char *name,
 534      bfd *abfd, asection *section, bfd_vma address);
 535 };
 536 \f
 537 /* The linker builds link_order structures which tell the code how to
 538    include input data in the output file.  */
 539
 540 /* These are the types of link_order structures.  */
 541
 542 enum bfd_link_order_type
 543 {
 544   bfd_undefined_link_order,     /* Undefined.  */
 545   bfd_indirect_link_order,      /* Built from a section.  */
 546   bfd_data_link_order,          /* Set to explicit data.  */
 547   bfd_section_reloc_link_order, /* Relocate against a section.  */
 548   bfd_symbol_reloc_link_order   /* Relocate against a symbol.  */
 549 };
 550
 551 /* This is the link_order structure itself.  These form a chain
 552    attached to the section whose contents they are describing.  */
 553
 554 struct bfd_link_order
 555 {
 556   /* Next link_order in chain.  */
 557   struct bfd_link_order *next;
 558   /* Type of link_order.  */
 559   enum bfd_link_order_type type;
 560   /* Offset within output section.  */
 561   bfd_vma offset;
 562   /* Size within output section.  */
 563   bfd_size_type size;
 564   /* Type specific information.  */
 565   union
 566     {
 567       struct
 568         {
 569           /* Section to include.  If this is used, then
 570              section->output_section must be the section the
 571              link_order is attached to, section->output_offset must
 572              equal the link_order offset field, and section->size
 573              must equal the link_order size field.  Maybe these
 574              restrictions should be relaxed someday.  */
 575           asection *section;
 576         } indirect;
 577       struct
 578         {
 579           /* Size of contents, or zero when contents size == size
 580              within output section.
 581              A non-zero value allows filling of the output section
 582              with an arbitrary repeated pattern.  */
 583           unsigned int size;
 584           /* Data to put into file.  */
 585           bfd_byte *contents;
 586         } data;
 587       struct
 588         {
 589           /* Description of reloc to generate.  Used for
 590              bfd_section_reloc_link_order and
 591              bfd_symbol_reloc_link_order.  */
 592           struct bfd_link_order_reloc *p;
 593         } reloc;
 594     } u;
 595 };
 596
 597 /* A linker order of type bfd_section_reloc_link_order or
 598    bfd_symbol_reloc_link_order means to create a reloc against a
 599    section or symbol, respectively.  This is used to implement -Ur to
 600    generate relocs for the constructor tables.  The
 601    bfd_link_order_reloc structure describes the reloc that BFD should
 602    create.  It is similar to a arelent, but I didn't use arelent
 603    because the linker does not know anything about most symbols, and
 604    any asymbol structure it creates will be partially meaningless.
 605    This information could logically be in the bfd_link_order struct,
 606    but I didn't want to waste the space since these types of relocs
 607    are relatively rare.  */
 608
 609 struct bfd_link_order_reloc
 610 {
 611   /* Reloc type.  */
 612   bfd_reloc_code_real_type reloc;
 613
 614   union
 615     {
 616       /* For type bfd_section_reloc_link_order, this is the section
 617          the reloc should be against.  This must be a section in the
 618          output BFD, not any of the input BFDs.  */
 619       asection *section;
 620       /* For type bfd_symbol_reloc_link_order, this is the name of the
 621          symbol the reloc should be against.  */
 622       const char *name;
 623     } u;
 624
 625   /* Addend to use.  The object file should contain zero.  The BFD
 626      backend is responsible for filling in the contents of the object
 627      file correctly.  For some object file formats (e.g., COFF) the
 628      addend must be stored into in the object file, and for some
 629      (e.g., SPARC a.out) it is kept in the reloc.  */
 630   bfd_vma addend;
 631 };
 632
 633 /* Allocate a new link_order for a section.  */
 634 extern struct bfd_link_order *bfd_new_link_order (bfd *, asection *);
 635
 636 /* These structures are used to describe version information for the
 637    ELF linker.  These structures could be manipulated entirely inside
 638    BFD, but it would be a pain.  Instead, the regular linker sets up
 639    these structures, and then passes them into BFD.  */
 640
 641 /* Glob pattern for a version.  */
 642
 643 struct bfd_elf_version_expr
 644 {
 645   /* Next glob pattern for this version.  */
 646   struct bfd_elf_version_expr *next;
 647   /* Glob pattern.  */
 648   const char *pattern;
 649   /* NULL for a glob pattern, otherwise a straight symbol.  */
 650   const char *symbol;
 651   /* Defined by ".symver".  */
 652   unsigned int symver : 1;
 653   /* Defined by version script.  */
 654   unsigned int script : 1;
 655   /* Pattern type.  */
 656 #define BFD_ELF_VERSION_C_TYPE          1
 657 #define BFD_ELF_VERSION_CXX_TYPE        2
 658 #define BFD_ELF_VERSION_JAVA_TYPE       4
 659   unsigned int mask : 3;
 660 };
 661
 662 struct bfd_elf_version_expr_head
 663 {
 664   /* List of all patterns, both wildcards and non-wildcards.  */
 665   struct bfd_elf_version_expr *list;
 666   /* Hash table for non-wildcards.  */
 667   void *htab;
 668   /* Remaining patterns.  */
 669   struct bfd_elf_version_expr *remaining;
 670   /* What kind of pattern types are present in list (bitmask).  */
 671   unsigned int mask;
 672 };
 673
 674 /* Version dependencies.  */
 675
 676 struct bfd_elf_version_deps
 677 {
 678   /* Next dependency for this version.  */
 679   struct bfd_elf_version_deps *next;
 680   /* The version which this version depends upon.  */
 681   struct bfd_elf_version_tree *version_needed;
 682 };
 683
 684 /* A node in the version tree.  */
 685
 686 struct bfd_elf_version_tree
 687 {
 688   /* Next version.  */
 689   struct bfd_elf_version_tree *next;
 690   /* Name of this version.  */
 691   const char *name;
 692   /* Version number.  */
 693   unsigned int vernum;
 694   /* Regular expressions for global symbols in this version.  */
 695   struct bfd_elf_version_expr_head globals;
 696   /* Regular expressions for local symbols in this version.  */
 697   struct bfd_elf_version_expr_head locals;
 698   /* List of versions which this version depends upon.  */
 699   struct bfd_elf_version_deps *deps;
 700   /* Index of the version name.  This is used within BFD.  */
 701   unsigned int name_indx;
 702   /* Whether this version tree was used.  This is used within BFD.  */
 703   int used;
 704   /* Matching hook.  */
 705   struct bfd_elf_version_expr *(*match)
 706     (struct bfd_elf_version_expr_head *head,
 707      struct bfd_elf_version_expr *prev, const char *sym);
 708 };
 709
 710 #endif