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 struct bfd_elf_dynamic_list;
 225
 226 /* This structure holds all the information needed to communicate
 227    between BFD and the linker when doing a link.  */
 228
 229 struct bfd_link_info
 230 {
 231   /* TRUE if BFD should generate a relocatable object file.  */
 232   unsigned int relocatable: 1;
 233
 234   /* TRUE if BFD should generate relocation information in the final
 235      executable.  */
 236   unsigned int emitrelocations: 1;
 237
 238   /* TRUE if BFD should generate a "task linked" object file,
 239      similar to relocatable but also with globals converted to
 240      statics.  */
 241   unsigned int task_link: 1;
 242
 243   /* TRUE if BFD should generate a shared object.  */
 244   unsigned int shared: 1;
 245
 246   /* TRUE if BFD should pre-bind symbols in a shared object.  */
 247   unsigned int symbolic: 1;
 248
 249   /* TRUE if BFD should export all symbols in the dynamic symbol table
 250      of an executable, rather than only those used.  */
 251   unsigned int export_dynamic: 1;
 252
 253   /* TRUE if shared objects should be linked directly, not shared.  */
 254   unsigned int static_link: 1;
 255
 256   /* TRUE if the output file should be in a traditional format.  This
 257      is equivalent to the setting of the BFD_TRADITIONAL_FORMAT flag
 258      on the output file, but may be checked when reading the input
 259      files.  */
 260   unsigned int traditional_format: 1;
 261
 262   /* TRUE if we want to produced optimized output files.  This might
 263      need much more time and therefore must be explicitly selected.  */
 264   unsigned int optimize: 1;
 265
 266   /* TRUE if ok to have multiple definition.  */
 267   unsigned int allow_multiple_definition: 1;
 268
 269   /* TRUE if ok to have version with no definition.  */
 270   unsigned int allow_undefined_version: 1;
 271
 272   /* TRUE if a default symbol version should be created and used for
 273      exported symbols.  */
 274   unsigned int create_default_symver: 1;
 275
 276   /* TRUE if a default symbol version should be created and used for
 277      imported symbols.  */
 278   unsigned int default_imported_symver: 1;
 279
 280   /* TRUE if symbols should be retained in memory, FALSE if they
 281      should be freed and reread.  */
 282   unsigned int keep_memory: 1;
 283
 284   /* TRUE if every symbol should be reported back via the notice
 285      callback.  */
 286   unsigned int notice_all: 1;
 287
 288   /* TRUE if executable should not contain copy relocs.
 289      Setting this true may result in a non-sharable text segment.  */
 290   unsigned int nocopyreloc: 1;
 291
 292   /* TRUE if the new ELF dynamic tags are enabled. */
 293   unsigned int new_dtags: 1;
 294
 295   /* TRUE if non-PLT relocs should be merged into one reloc section
 296      and sorted so that relocs against the same symbol come together.  */
 297   unsigned int combreloc: 1;
 298
 299   /* TRUE if .eh_frame_hdr section and PT_GNU_EH_FRAME ELF segment
 300      should be created.  */
 301   unsigned int eh_frame_hdr: 1;
 302
 303   /* TRUE if global symbols in discarded sections should be stripped.  */
 304   unsigned int strip_discarded: 1;
 305
 306   /* TRUE if generating a position independent executable.  */
 307   unsigned int pie: 1;
 308
 309   /* TRUE if generating an executable, position independent or not.  */
 310   unsigned int executable : 1;
 311
 312   /* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W|PF_X
 313      flags.  */
 314   unsigned int execstack: 1;
 315
 316   /* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W
 317      flags.  */
 318   unsigned int noexecstack: 1;
 319
 320   /* TRUE if PT_GNU_RELRO segment should be created.  */
 321   unsigned int relro: 1;
 322
 323   /* TRUE if we should warn when adding a DT_TEXTREL to a shared object.  */
 324   unsigned int warn_shared_textrel: 1;
 325
 326   /* TRUE if unreferenced sections should be removed.  */
 327   unsigned int gc_sections: 1;
 328
 329   /* TRUE if user shoudl be informed of removed unreferenced sections.  */
 330   unsigned int print_gc_sections: 1;
 331
 332   /* TRUE if .hash section should be created.  */
 333   unsigned int emit_hash: 1;
 334
 335   /* TRUE if .gnu.hash section should be created.  */
 336   unsigned int emit_gnu_hash: 1;
 337
 338   /* What to do with unresolved symbols in an object file.
 339      When producing executables the default is GENERATE_ERROR.
 340      When producing shared libraries the default is IGNORE.  The
 341      assumption with shared libraries is that the reference will be
 342      resolved at load/execution time.  */
 343   enum report_method unresolved_syms_in_objects;
 344
 345   /* What to do with unresolved symbols in a shared library.
 346      The same defaults apply.  */
 347   enum report_method unresolved_syms_in_shared_libs;
 348
 349   /* Which symbols to strip.  */
 350   enum bfd_link_strip strip;
 351
 352   /* Which local symbols to discard.  */
 353   enum bfd_link_discard discard;
 354
 355   /* Criteria for skipping symbols when detemining
 356      whether to include an object from an archive. */
 357   enum bfd_link_common_skip_ar_aymbols common_skip_ar_aymbols;
 358
 359   /* Char that may appear as the first char of a symbol, but should be
 360      skipped (like symbol_leading_char) when looking up symbols in
 361      wrap_hash.  Used by PowerPC Linux for 'dot' symbols.  */
 362   char wrap_char;
 363
 364   /* Function callbacks.  */
 365   const struct bfd_link_callbacks *callbacks;
 366
 367   /* Hash table handled by BFD.  */
 368   struct bfd_link_hash_table *hash;
 369
 370   /* Hash table of symbols to keep.  This is NULL unless strip is
 371      strip_some.  */
 372   struct bfd_hash_table *keep_hash;
 373
 374   /* Hash table of symbols to report back via the notice callback.  If
 375      this is NULL, and notice_all is FALSE, then no symbols are
 376      reported back.  */
 377   struct bfd_hash_table *notice_hash;
 378
 379   /* Hash table of symbols which are being wrapped (the --wrap linker
 380      option).  If this is NULL, no symbols are being wrapped.  */
 381   struct bfd_hash_table *wrap_hash;
 382
 383   /* The list of input BFD's involved in the link.  These are chained
 384      together via the link_next field.  */
 385   bfd *input_bfds;
 386
 387   /* If a symbol should be created for each input BFD, this is section
 388      where those symbols should be placed.  It must be a section in
 389      the output BFD.  It may be NULL, in which case no such symbols
 390      will be created.  This is to support CREATE_OBJECT_SYMBOLS in the
 391      linker command language.  */
 392   asection *create_object_symbols_section;
 393
 394   /* List of global symbol names that are starting points for marking
 395      sections against garbage collection.  */
 396   struct bfd_sym_chain *gc_sym_list;
 397
 398   /* If a base output file is wanted, then this points to it */
 399   void *base_file;
 400
 401   /* The function to call when the executable or shared object is
 402      loaded.  */
 403   const char *init_function;
 404
 405   /* The function to call when the executable or shared object is
 406      unloaded.  */
 407   const char *fini_function;
 408
 409   /* Number of relaxation passes.  Usually only one relaxation pass
 410      is needed.  But a backend can have as many relaxation passes as
 411      necessary.  During bfd_relax_section call, it is set to the
 412      current pass, starting from 0.  */
 413   int relax_pass;
 414
 415   /* Non-zero if auto-import thunks for DATA items in pei386 DLLs
 416      should be generated/linked against.  Set to 1 if this feature
 417      is explicitly requested by the user, -1 if enabled by default.  */
 418   int pei386_auto_import;
 419
 420   /* Non-zero if runtime relocs for DATA items with non-zero addends
 421      in pei386 DLLs should be generated.  Set to 1 if this feature
 422      is explicitly requested by the user, -1 if enabled by default.  */
 423   int pei386_runtime_pseudo_reloc;
 424
 425   /* How many spare .dynamic DT_NULL entries should be added?  */
 426   unsigned int spare_dynamic_tags;
 427
 428   /* May be used to set DT_FLAGS for ELF. */
 429   bfd_vma flags;
 430
 431   /* May be used to set DT_FLAGS_1 for ELF. */
 432   bfd_vma flags_1;
 433
 434   /* Start and end of RELRO region.  */
 435   bfd_vma relro_start, relro_end;
 436
 437   /* List of symbols should be dynamic.  */
 438   struct bfd_elf_dynamic_list *dynamic;
 439 };
 440
 441 /* This structures holds a set of callback functions.  These are
 442    called by the BFD linker routines.  Except for einfo, the first
 443    argument to each callback function is the bfd_link_info structure
 444    being used and each function returns a boolean value.  If the
 445    function returns FALSE, then the BFD function which called it should
 446    return with a failure indication.  */
 447
 448 struct bfd_link_callbacks
 449 {
 450   /* A function which is called when an object is added from an
 451      archive.  ABFD is the archive element being added.  NAME is the
 452      name of the symbol which caused the archive element to be pulled
 453      in.  */
 454   bfd_boolean (*add_archive_element)
 455     (struct bfd_link_info *, bfd *abfd, const char *name);
 456   /* A function which is called when a symbol is found with multiple
 457      definitions.  NAME is the symbol which is defined multiple times.
 458      OBFD is the old BFD, OSEC is the old section, OVAL is the old
 459      value, NBFD is the new BFD, NSEC is the new section, and NVAL is
 460      the new value.  OBFD may be NULL.  OSEC and NSEC may be
 461      bfd_com_section or bfd_ind_section.  */
 462   bfd_boolean (*multiple_definition)
 463     (struct bfd_link_info *, const char *name,
 464      bfd *obfd, asection *osec, bfd_vma oval,
 465      bfd *nbfd, asection *nsec, bfd_vma nval);
 466   /* A function which is called when a common symbol is defined
 467      multiple times.  NAME is the symbol appearing multiple times.
 468      OBFD is the BFD of the existing symbol; it may be NULL if this is
 469      not known.  OTYPE is the type of the existing symbol, which may
 470      be bfd_link_hash_defined, bfd_link_hash_defweak,
 471      bfd_link_hash_common, or bfd_link_hash_indirect.  If OTYPE is
 472      bfd_link_hash_common, OSIZE is the size of the existing symbol.
 473      NBFD is the BFD of the new symbol.  NTYPE is the type of the new
 474      symbol, one of bfd_link_hash_defined, bfd_link_hash_common, or
 475      bfd_link_hash_indirect.  If NTYPE is bfd_link_hash_common, NSIZE
 476      is the size of the new symbol.  */
 477   bfd_boolean (*multiple_common)
 478     (struct bfd_link_info *, const char *name,
 479      bfd *obfd, enum bfd_link_hash_type otype, bfd_vma osize,
 480      bfd *nbfd, enum bfd_link_hash_type ntype, bfd_vma nsize);
 481   /* A function which is called to add a symbol to a set.  ENTRY is
 482      the link hash table entry for the set itself (e.g.,
 483      __CTOR_LIST__).  RELOC is the relocation to use for an entry in
 484      the set when generating a relocatable file, and is also used to
 485      get the size of the entry when generating an executable file.
 486      ABFD, SEC and VALUE identify the value to add to the set.  */
 487   bfd_boolean (*add_to_set)
 488     (struct bfd_link_info *, struct bfd_link_hash_entry *entry,
 489      bfd_reloc_code_real_type reloc, bfd *abfd, asection *sec, bfd_vma value);
 490   /* A function which is called when the name of a g++ constructor or
 491      destructor is found.  This is only called by some object file
 492      formats.  CONSTRUCTOR is TRUE for a constructor, FALSE for a
 493      destructor.  This will use BFD_RELOC_CTOR when generating a
 494      relocatable file.  NAME is the name of the symbol found.  ABFD,
 495      SECTION and VALUE are the value of the symbol.  */
 496   bfd_boolean (*constructor)
 497     (struct bfd_link_info *, bfd_boolean constructor, const char *name,
 498      bfd *abfd, asection *sec, bfd_vma value);
 499   /* A function which is called to issue a linker warning.  For
 500      example, this is called when there is a reference to a warning
 501      symbol.  WARNING is the warning to be issued.  SYMBOL is the name
 502      of the symbol which triggered the warning; it may be NULL if
 503      there is none.  ABFD, SECTION and ADDRESS identify the location
 504      which trigerred the warning; either ABFD or SECTION or both may
 505      be NULL if the location is not known.  */
 506   bfd_boolean (*warning)
 507     (struct bfd_link_info *, const char *warning, const char *symbol,
 508      bfd *abfd, asection *section, bfd_vma address);
 509   /* A function which is called when a relocation is attempted against
 510      an undefined symbol.  NAME is the symbol which is undefined.
 511      ABFD, SECTION and ADDRESS identify the location from which the
 512      reference is made. FATAL indicates whether an undefined symbol is
 513      a fatal error or not. In some cases SECTION may be NULL.  */
 514   bfd_boolean (*undefined_symbol)
 515     (struct bfd_link_info *, const char *name, bfd *abfd,
 516      asection *section, bfd_vma address, bfd_boolean fatal);
 517   /* A function which is called when a reloc overflow occurs. ENTRY is
 518      the link hash table entry for the symbol the reloc is against.
 519      NAME is the name of the local symbol or section the reloc is
 520      against, RELOC_NAME is the name of the relocation, and ADDEND is
 521      any addend that is used.  ABFD, SECTION and ADDRESS identify the
 522      location at which the overflow occurs; 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 (*reloc_overflow)
 526     (struct bfd_link_info *, struct bfd_link_hash_entry *entry,
 527      const char *name, const char *reloc_name, bfd_vma addend,
 528      bfd *abfd, asection *section, bfd_vma address);
 529   /* A function which is called when a dangerous reloc is performed.
 530      MESSAGE is an appropriate message.
 531      ABFD, SECTION and ADDRESS identify the location at which the
 532      problem occurred; if this is the result of a
 533      bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
 534      ABFD will be NULL.  */
 535   bfd_boolean (*reloc_dangerous)
 536     (struct bfd_link_info *, const char *message,
 537      bfd *abfd, asection *section, bfd_vma address);
 538   /* A function which is called when a reloc is found to be attached
 539      to a symbol which is not being written out.  NAME is the name of
 540      the symbol.  ABFD, SECTION and ADDRESS identify the location of
 541      the reloc; if this is the result of a
 542      bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
 543      ABFD will be NULL.  */
 544   bfd_boolean (*unattached_reloc)
 545     (struct bfd_link_info *, const char *name,
 546      bfd *abfd, asection *section, bfd_vma address);
 547   /* A function which is called when a symbol in notice_hash is
 548      defined or referenced.  NAME is the symbol.  ABFD, SECTION and
 549      ADDRESS are the value of the symbol.  If SECTION is
 550      bfd_und_section, this is a reference.  */
 551   bfd_boolean (*notice)
 552     (struct bfd_link_info *, const char *name,
 553      bfd *abfd, asection *section, bfd_vma address);
 554   /* General link info message.  */
 555   void (*einfo)
 556     (const char *fmt, ...);
 557 };
 558 \f
 559 /* The linker builds link_order structures which tell the code how to
 560    include input data in the output file.  */
 561
 562 /* These are the types of link_order structures.  */
 563
 564 enum bfd_link_order_type
 565 {
 566   bfd_undefined_link_order,     /* Undefined.  */
 567   bfd_indirect_link_order,      /* Built from a section.  */
 568   bfd_data_link_order,          /* Set to explicit data.  */
 569   bfd_section_reloc_link_order, /* Relocate against a section.  */
 570   bfd_symbol_reloc_link_order   /* Relocate against a symbol.  */
 571 };
 572
 573 /* This is the link_order structure itself.  These form a chain
 574    attached to the output section whose contents they are describing.  */
 575
 576 struct bfd_link_order
 577 {
 578   /* Next link_order in chain.  */
 579   struct bfd_link_order *next;
 580   /* Type of link_order.  */
 581   enum bfd_link_order_type type;
 582   /* Offset within output section.  */
 583   bfd_vma offset;
 584   /* Size within output section.  */
 585   bfd_size_type size;
 586   /* Type specific information.  */
 587   union
 588     {
 589       struct
 590         {
 591           /* Section to include.  If this is used, then
 592              section->output_section must be the section the
 593              link_order is attached to, section->output_offset must
 594              equal the link_order offset field, and section->size
 595              must equal the link_order size field.  Maybe these
 596              restrictions should be relaxed someday.  */
 597           asection *section;
 598         } indirect;
 599       struct
 600         {
 601           /* Size of contents, or zero when contents size == size
 602              within output section.
 603              A non-zero value allows filling of the output section
 604              with an arbitrary repeated pattern.  */
 605           unsigned int size;
 606           /* Data to put into file.  */
 607           bfd_byte *contents;
 608         } data;
 609       struct
 610         {
 611           /* Description of reloc to generate.  Used for
 612              bfd_section_reloc_link_order and
 613              bfd_symbol_reloc_link_order.  */
 614           struct bfd_link_order_reloc *p;
 615         } reloc;
 616     } u;
 617 };
 618
 619 /* A linker order of type bfd_section_reloc_link_order or
 620    bfd_symbol_reloc_link_order means to create a reloc against a
 621    section or symbol, respectively.  This is used to implement -Ur to
 622    generate relocs for the constructor tables.  The
 623    bfd_link_order_reloc structure describes the reloc that BFD should
 624    create.  It is similar to a arelent, but I didn't use arelent
 625    because the linker does not know anything about most symbols, and
 626    any asymbol structure it creates will be partially meaningless.
 627    This information could logically be in the bfd_link_order struct,
 628    but I didn't want to waste the space since these types of relocs
 629    are relatively rare.  */
 630
 631 struct bfd_link_order_reloc
 632 {
 633   /* Reloc type.  */
 634   bfd_reloc_code_real_type reloc;
 635
 636   union
 637     {
 638       /* For type bfd_section_reloc_link_order, this is the section
 639          the reloc should be against.  This must be a section in the
 640          output BFD, not any of the input BFDs.  */
 641       asection *section;
 642       /* For type bfd_symbol_reloc_link_order, this is the name of the
 643          symbol the reloc should be against.  */
 644       const char *name;
 645     } u;
 646
 647   /* Addend to use.  The object file should contain zero.  The BFD
 648      backend is responsible for filling in the contents of the object
 649      file correctly.  For some object file formats (e.g., COFF) the
 650      addend must be stored into in the object file, and for some
 651      (e.g., SPARC a.out) it is kept in the reloc.  */
 652   bfd_vma addend;
 653 };
 654
 655 /* Allocate a new link_order for a section.  */
 656 extern struct bfd_link_order *bfd_new_link_order (bfd *, asection *);
 657
 658 /* These structures are used to describe version information for the
 659    ELF linker.  These structures could be manipulated entirely inside
 660    BFD, but it would be a pain.  Instead, the regular linker sets up
 661    these structures, and then passes them into BFD.  */
 662
 663 /* Glob pattern for a version.  */
 664
 665 struct bfd_elf_version_expr
 666 {
 667   /* Next glob pattern for this version.  */
 668   struct bfd_elf_version_expr *next;
 669   /* Glob pattern.  */
 670   const char *pattern;
 671   /* NULL for a glob pattern, otherwise a straight symbol.  */
 672   const char *symbol;
 673   /* Defined by ".symver".  */
 674   unsigned int symver : 1;
 675   /* Defined by version script.  */
 676   unsigned int script : 1;
 677   /* Pattern type.  */
 678 #define BFD_ELF_VERSION_C_TYPE          1
 679 #define BFD_ELF_VERSION_CXX_TYPE        2
 680 #define BFD_ELF_VERSION_JAVA_TYPE       4
 681   unsigned int mask : 3;
 682 };
 683
 684 struct bfd_elf_version_expr_head
 685 {
 686   /* List of all patterns, both wildcards and non-wildcards.  */
 687   struct bfd_elf_version_expr *list;
 688   /* Hash table for non-wildcards.  */
 689   void *htab;
 690   /* Remaining patterns.  */
 691   struct bfd_elf_version_expr *remaining;
 692   /* What kind of pattern types are present in list (bitmask).  */
 693   unsigned int mask;
 694 };
 695
 696 /* Version dependencies.  */
 697
 698 struct bfd_elf_version_deps
 699 {
 700   /* Next dependency for this version.  */
 701   struct bfd_elf_version_deps *next;
 702   /* The version which this version depends upon.  */
 703   struct bfd_elf_version_tree *version_needed;
 704 };
 705
 706 /* A node in the version tree.  */
 707
 708 struct bfd_elf_version_tree
 709 {
 710   /* Next version.  */
 711   struct bfd_elf_version_tree *next;
 712   /* Name of this version.  */
 713   const char *name;
 714   /* Version number.  */
 715   unsigned int vernum;
 716   /* Regular expressions for global symbols in this version.  */
 717   struct bfd_elf_version_expr_head globals;
 718   /* Regular expressions for local symbols in this version.  */
 719   struct bfd_elf_version_expr_head locals;
 720   /* List of versions which this version depends upon.  */
 721   struct bfd_elf_version_deps *deps;
 722   /* Index of the version name.  This is used within BFD.  */
 723   unsigned int name_indx;
 724   /* Whether this version tree was used.  This is used within BFD.  */
 725   int used;
 726   /* Matching hook.  */
 727   struct bfd_elf_version_expr *(*match)
 728     (struct bfd_elf_version_expr_head *head,
 729      struct bfd_elf_version_expr *prev, const char *sym);
 730 };
 731
 732 struct bfd_elf_dynamic_list
 733 {
 734   struct bfd_elf_version_expr_head head;
 735   struct bfd_elf_version_expr *(*match)
 736     (struct bfd_elf_version_expr_head *head,
 737      struct bfd_elf_version_expr *prev, const char *sym);
 738 };
 739
 740 #endif