include/bfdlink.h

   1 /* bfdlink.h -- header file for BFD link routines
   2    Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2002, 2003,
   3    2004 Free Software Foundation, Inc.
   4    Written by Steve Chamberlain and Ian Lance Taylor, Cygnus Support.
   5
   6    This file is part of BFD, the Binary File Descriptor library.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  21
  22 #ifndef BFDLINK_H
  23 #define BFDLINK_H
  24
  25 /* Which symbols to strip during a link.  */
  26 enum bfd_link_strip
  27 {
  28   strip_none,           /* Don't strip any symbols.  */
  29   strip_debugger,       /* Strip debugging symbols.  */
  30   strip_some,           /* keep_hash is the list of symbols to keep.  */
  31   strip_all             /* Strip all symbols.  */
  32 };
  33
  34 /* Which local symbols to discard during a link.  This is irrelevant
  35    if strip_all is used.  */
  36 enum bfd_link_discard
  37 {
  38   discard_sec_merge,    /* Discard local temporary symbols in SEC_MERGE
  39                            sections.  */
  40   discard_none,         /* Don't discard any locals.  */
  41   discard_l,            /* Discard local temporary symbols.  */
  42   discard_all           /* Discard all locals.  */
  43 };
  44
  45 /* Describes the type of hash table entry structure being used.
  46    Different hash table structure have different fields and so
  47    support different linking features.  */
  48 enum bfd_link_hash_table_type
  49   {
  50     bfd_link_generic_hash_table,
  51     bfd_link_elf_hash_table
  52   };
  53 \f
  54 /* These are the possible types of an entry in the BFD link hash
  55    table.  */
  56
  57 enum bfd_link_hash_type
  58 {
  59   bfd_link_hash_new,            /* Symbol is new.  */
  60   bfd_link_hash_undefined,      /* Symbol seen before, but undefined.  */
  61   bfd_link_hash_undefweak,      /* Symbol is weak and undefined.  */
  62   bfd_link_hash_defined,        /* Symbol is defined.  */
  63   bfd_link_hash_defweak,        /* Symbol is weak and defined.  */
  64   bfd_link_hash_common,         /* Symbol is common.  */
  65   bfd_link_hash_indirect,       /* Symbol is an indirect link.  */
  66   bfd_link_hash_warning         /* Like indirect, but warn if referenced.  */
  67 };
  68
  69 enum bfd_link_common_skip_ar_aymbols
  70 {
  71   bfd_link_common_skip_none,
  72   bfd_link_common_skip_text,
  73   bfd_link_common_skip_data,
  74   bfd_link_common_skip_all
  75 };
  76
  77 /* The linking routines use a hash table which uses this structure for
  78    its elements.  */
  79
  80 struct bfd_link_hash_entry
  81 {
  82   /* Base hash table entry structure.  */
  83   struct bfd_hash_entry root;
  84
  85   /* Type of this entry.  */
  86   enum bfd_link_hash_type type;
  87
  88   /* Undefined and common symbols are kept in a linked list through
  89      this field.  This field is not in the union because that would
  90      force us to remove entries from the list when we changed their
  91      type, which would force the list to be doubly linked, which would
  92      waste more memory.  When an undefined or common symbol is
  93      created, it should be added to this list, the head of which is in
  94      the link hash table itself.  As symbols are defined, they need
  95      not be removed from the list; anything which reads the list must
  96      doublecheck the symbol type.
  97
  98      Weak symbols are not kept on this list.
  99
 100      Defined and defweak symbols use this field as a reference marker.
 101      If the field is not NULL, or this structure is the tail of the
 102      undefined symbol list, the symbol has been referenced.  If the
 103      symbol is undefined and becomes defined, this field will
 104      automatically be non-NULL since the symbol will have been on the
 105      undefined symbol list.  */
 106   struct bfd_link_hash_entry *und_next;
 107
 108   /* A union of information depending upon the type.  */
 109   union
 110     {
 111       /* Nothing is kept for bfd_hash_new.  */
 112       /* bfd_link_hash_undefined, bfd_link_hash_undefweak.  */
 113       struct
 114         {
 115           bfd *abfd;            /* BFD symbol was found in.  */
 116         } undef;
 117       /* bfd_link_hash_defined, bfd_link_hash_defweak.  */
 118       struct
 119         {
 120           bfd_vma value;        /* Symbol value.  */
 121           asection *section;    /* Symbol section.  */
 122         } def;
 123       /* bfd_link_hash_indirect, bfd_link_hash_warning.  */
 124       struct
 125         {
 126           struct bfd_link_hash_entry *link;     /* Real symbol.  */
 127           const char *warning;  /* Warning (bfd_link_hash_warning only).  */
 128         } i;
 129       /* bfd_link_hash_common.  */
 130       struct
 131         {
 132           /* The linker needs to know three things about common
 133              symbols: the size, the alignment, and the section in
 134              which the symbol should be placed.  We store the size
 135              here, and we allocate a small structure to hold the
 136              section and the alignment.  The alignment is stored as a
 137              power of two.  We don't store all the information
 138              directly because we don't want to increase the size of
 139              the union; this structure is a major space user in the
 140              linker.  */
 141           bfd_size_type size;   /* Common symbol size.  */
 142           struct bfd_link_hash_common_entry
 143             {
 144               unsigned int alignment_power;     /* Alignment.  */
 145               asection *section;                /* Symbol section.  */
 146             } *p;
 147         } c;
 148     } u;
 149 };
 150
 151 /* This is the link hash table.  It is a derived class of
 152    bfd_hash_table.  */
 153
 154 struct bfd_link_hash_table
 155 {
 156   /* The hash table itself.  */
 157   struct bfd_hash_table table;
 158   /* The back end which created this hash table.  This indicates the
 159      type of the entries in the hash table, which is sometimes
 160      important information when linking object files of different
 161      types together.  */
 162   const bfd_target *creator;
 163   /* A linked list of undefined and common symbols, linked through the
 164      next field in the bfd_link_hash_entry structure.  */
 165   struct bfd_link_hash_entry *undefs;
 166   /* Entries are added to the tail of the undefs list.  */
 167   struct bfd_link_hash_entry *undefs_tail;
 168   /* The type of the link hash table.  */
 169   enum bfd_link_hash_table_type type;
 170 };
 171
 172 /* Look up an entry in a link hash table.  If FOLLOW is TRUE, this
 173    follows bfd_link_hash_indirect and bfd_link_hash_warning links to
 174    the real symbol.  */
 175 extern struct bfd_link_hash_entry *bfd_link_hash_lookup
 176   (struct bfd_link_hash_table *, const char *, bfd_boolean create,
 177    bfd_boolean copy, bfd_boolean follow);
 178
 179 /* Look up an entry in the main linker hash table if the symbol might
 180    be wrapped.  This should only be used for references to an
 181    undefined symbol, not for definitions of a symbol.  */
 182
 183 extern struct bfd_link_hash_entry *bfd_wrapped_link_hash_lookup
 184   (bfd *, struct bfd_link_info *, const char *, bfd_boolean,
 185    bfd_boolean, bfd_boolean);
 186
 187 /* Traverse a link hash table.  */
 188 extern void bfd_link_hash_traverse
 189   (struct bfd_link_hash_table *,
 190     bfd_boolean (*) (struct bfd_link_hash_entry *, void *),
 191     void *);
 192
 193 /* Add an entry to the undefs list.  */
 194 extern void bfd_link_add_undef
 195   (struct bfd_link_hash_table *, struct bfd_link_hash_entry *);
 196
 197 struct bfd_sym_chain
 198 {
 199   struct bfd_sym_chain *next;
 200   const char *name;
 201 };
 202 \f
 203 /* How to handle unresolved symbols.
 204    There are four possibilities which are enumerated below:  */
 205 enum report_method
 206 {
 207   /* This is the initial value when then link_info structure is created.
 208      It allows the various stages of the linker to determine whether they
 209      allowed to set the value.  */
 210   RM_NOT_YET_SET = 0,
 211   RM_IGNORE,
 212   RM_GENERATE_WARNING,
 213   RM_GENERATE_ERROR
 214 };
 215
 216 /* This structure holds all the information needed to communicate
 217    between BFD and the linker when doing a link.  */
 218
 219 struct bfd_link_info
 220 {
 221   /* TRUE if BFD should generate a relocatable object file.  */
 222   unsigned int relocatable: 1;
 223
 224   /* TRUE if BFD should generate relocation information in the final
 225      executable.  */
 226   unsigned int emitrelocations: 1;
 227
 228   /* TRUE if BFD should generate a "task linked" object file,
 229      similar to relocatable but also with globals converted to
 230      statics.  */
 231   unsigned int task_link: 1;
 232
 233   /* TRUE if BFD should generate a shared object.  */
 234   unsigned int shared: 1;
 235
 236   /* TRUE if BFD should pre-bind symbols in a shared object.  */
 237   unsigned int symbolic: 1;
 238
 239   /* TRUE if BFD should export all symbols in the dynamic symbol table
 240      of an executable, rather than only those used.  */
 241   unsigned int export_dynamic: 1;
 242
 243   /* TRUE if shared objects should be linked directly, not shared.  */
 244   unsigned int static_link: 1;
 245
 246   /* TRUE if the output file should be in a traditional format.  This
 247      is equivalent to the setting of the BFD_TRADITIONAL_FORMAT flag
 248      on the output file, but may be checked when reading the input
 249      files.  */
 250   unsigned int traditional_format: 1;
 251
 252   /* TRUE if we want to produced optimized output files.  This might
 253      need much more time and therefore must be explicitly selected.  */
 254   unsigned int optimize: 1;
 255
 256   /* TRUE if ok to have multiple definition.  */
 257   unsigned int allow_multiple_definition: 1;
 258
 259   /* TRUE if ok to have version with no definition.  */
 260   unsigned int allow_undefined_version: 1;
 261
 262   /* TRUE if symbols should be retained in memory, FALSE if they
 263      should be freed and reread.  */
 264   unsigned int keep_memory: 1;
 265
 266   /* TRUE if every symbol should be reported back via the notice
 267      callback.  */
 268   unsigned int notice_all: 1;
 269
 270   /* TRUE if executable should not contain copy relocs.
 271      Setting this true may result in a non-sharable text segment.  */
 272   unsigned int nocopyreloc: 1;
 273
 274   /* TRUE if the new ELF dynamic tags are enabled. */
 275   unsigned int new_dtags: 1;
 276
 277   /* TRUE if non-PLT relocs should be merged into one reloc section
 278      and sorted so that relocs against the same symbol come together.  */
 279   unsigned int combreloc: 1;
 280
 281   /* TRUE if .eh_frame_hdr section and PT_GNU_EH_FRAME ELF segment
 282      should be created.  */
 283   unsigned int eh_frame_hdr: 1;
 284
 285   /* TRUE if global symbols in discarded sections should be stripped.  */
 286   unsigned int strip_discarded: 1;
 287
 288   /* TRUE if the final relax pass is needed.  */
 289   unsigned int need_relax_finalize: 1;
 290
 291   /* TRUE if generating a position independent executable.  */
 292   unsigned int pie: 1;
 293
 294   /* TRUE if generating an executable, position independent or not.  */
 295   unsigned int executable : 1;
 296
 297   /* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W|PF_X
 298      flags.  */
 299   unsigned int execstack: 1;
 300
 301   /* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W
 302      flags.  */
 303   unsigned int noexecstack: 1;
 304
 305   /* What to do with unresolved symbols in an object file.
 306      When producing executables the default is GENERATE_ERROR.
 307      When producing shared libraries the default is IGNORE.  The
 308      assumption with shared libraries is that the reference will be
 309      resolved at load/execution time.  */
 310   enum report_method unresolved_syms_in_objects;
 311
 312   /* What to do with unresolved symbols in a shared library.
 313      The same defaults apply.  */
 314   enum report_method unresolved_syms_in_shared_libs;
 315
 316   /* Which symbols to strip.  */
 317   enum bfd_link_strip strip;
 318
 319   /* Which local symbols to discard.  */
 320   enum bfd_link_discard discard;
 321
 322   /* Criteria for skipping symbols when detemining
 323      whether to include an object from an archive. */
 324   enum bfd_link_common_skip_ar_aymbols common_skip_ar_aymbols;
 325
 326   /* Char that may appear as the first char of a symbol, but should be
 327      skipped (like symbol_leading_char) when looking up symbols in
 328      wrap_hash.  Used by PowerPC Linux for 'dot' symbols.  */
 329   char wrap_char;
 330
 331   /* Function callbacks.  */
 332   const struct bfd_link_callbacks *callbacks;
 333
 334   /* Hash table handled by BFD.  */
 335   struct bfd_link_hash_table *hash;
 336
 337   /* Hash table of symbols to keep.  This is NULL unless strip is
 338      strip_some.  */
 339   struct bfd_hash_table *keep_hash;
 340
 341   /* Hash table of symbols to report back via the notice callback.  If
 342      this is NULL, and notice_all is FALSE, then no symbols are
 343      reported back.  */
 344   struct bfd_hash_table *notice_hash;
 345
 346   /* Hash table of symbols which are being wrapped (the --wrap linker
 347      option).  If this is NULL, no symbols are being wrapped.  */
 348   struct bfd_hash_table *wrap_hash;
 349
 350   /* The list of input BFD's involved in the link.  These are chained
 351      together via the link_next field.  */
 352   bfd *input_bfds;
 353
 354   /* If a symbol should be created for each input BFD, this is section
 355      where those symbols should be placed.  It must be a section in
 356      the output BFD.  It may be NULL, in which case no such symbols
 357      will be created.  This is to support CREATE_OBJECT_SYMBOLS in the
 358      linker command language.  */
 359   asection *create_object_symbols_section;
 360
 361   /* List of global symbol names that are starting points for marking
 362      sections against garbage collection.  */
 363   struct bfd_sym_chain *gc_sym_list;
 364
 365   /* If a base output file is wanted, then this points to it */
 366   void *base_file;
 367
 368   /* The function to call when the executable or shared object is
 369      loaded.  */
 370   const char *init_function;
 371
 372   /* The function to call when the executable or shared object is
 373      unloaded.  */
 374   const char *fini_function;
 375
 376   /* Non-zero if auto-import thunks for DATA items in pei386 DLLs
 377      should be generated/linked against.  Set to 1 if this feature
 378      is explicitly requested by the user, -1 if enabled by default.  */
 379   int pei386_auto_import;
 380
 381   /* Non-zero if runtime relocs for DATA items with non-zero addends
 382      in pei386 DLLs should be generated.  Set to 1 if this feature
 383      is explicitly requested by the user, -1 if enabled by default.  */
 384   int pei386_runtime_pseudo_reloc;
 385
 386   /* How many spare .dynamic DT_NULL entries should be added?  */
 387   unsigned int spare_dynamic_tags;
 388
 389   /* May be used to set DT_FLAGS for ELF. */
 390   bfd_vma flags;
 391
 392   /* May be used to set DT_FLAGS_1 for ELF. */
 393   bfd_vma flags_1;
 394 };
 395
 396 /* This structures holds a set of callback functions.  These are
 397    called by the BFD linker routines.  The first argument to each
 398    callback function is the bfd_link_info structure being used.  Each
 399    function returns a boolean value.  If the function returns FALSE,
 400    then the BFD function which called it will return with a failure
 401    indication.  */
 402
 403 struct bfd_link_callbacks
 404 {
 405   /* A function which is called when an object is added from an
 406      archive.  ABFD is the archive element being added.  NAME is the
 407      name of the symbol which caused the archive element to be pulled
 408      in.  */
 409   bfd_boolean (*add_archive_element)
 410     (struct bfd_link_info *, bfd *abfd, const char *name);
 411   /* A function which is called when a symbol is found with multiple
 412      definitions.  NAME is the symbol which is defined multiple times.
 413      OBFD is the old BFD, OSEC is the old section, OVAL is the old
 414      value, NBFD is the new BFD, NSEC is the new section, and NVAL is
 415      the new value.  OBFD may be NULL.  OSEC and NSEC may be
 416      bfd_com_section or bfd_ind_section.  */
 417   bfd_boolean (*multiple_definition)
 418     (struct bfd_link_info *, const char *name,
 419      bfd *obfd, asection *osec, bfd_vma oval,
 420      bfd *nbfd, asection *nsec, bfd_vma nval);
 421   /* A function which is called when a common symbol is defined
 422      multiple times.  NAME is the symbol appearing multiple times.
 423      OBFD is the BFD of the existing symbol; it may be NULL if this is
 424      not known.  OTYPE is the type of the existing symbol, which may
 425      be bfd_link_hash_defined, bfd_link_hash_defweak,
 426      bfd_link_hash_common, or bfd_link_hash_indirect.  If OTYPE is
 427      bfd_link_hash_common, OSIZE is the size of the existing symbol.
 428      NBFD is the BFD of the new symbol.  NTYPE is the type of the new
 429      symbol, one of bfd_link_hash_defined, bfd_link_hash_common, or
 430      bfd_link_hash_indirect.  If NTYPE is bfd_link_hash_common, NSIZE
 431      is the size of the new symbol.  */
 432   bfd_boolean (*multiple_common)
 433     (struct bfd_link_info *, const char *name,
 434      bfd *obfd, enum bfd_link_hash_type otype, bfd_vma osize,
 435      bfd *nbfd, enum bfd_link_hash_type ntype, bfd_vma nsize);
 436   /* A function which is called to add a symbol to a set.  ENTRY is
 437      the link hash table entry for the set itself (e.g.,
 438      __CTOR_LIST__).  RELOC is the relocation to use for an entry in
 439      the set when generating a relocatable file, and is also used to
 440      get the size of the entry when generating an executable file.
 441      ABFD, SEC and VALUE identify the value to add to the set.  */
 442   bfd_boolean (*add_to_set)
 443     (struct bfd_link_info *, struct bfd_link_hash_entry *entry,
 444      bfd_reloc_code_real_type reloc, bfd *abfd, asection *sec, bfd_vma value);
 445   /* A function which is called when the name of a g++ constructor or
 446      destructor is found.  This is only called by some object file
 447      formats.  CONSTRUCTOR is TRUE for a constructor, FALSE for a
 448      destructor.  This will use BFD_RELOC_CTOR when generating a
 449      relocatable file.  NAME is the name of the symbol found.  ABFD,
 450      SECTION and VALUE are the value of the symbol.  */
 451   bfd_boolean (*constructor)
 452     (struct bfd_link_info *, bfd_boolean constructor, const char *name,
 453      bfd *abfd, asection *sec, bfd_vma value);
 454   /* A function which is called to issue a linker warning.  For
 455      example, this is called when there is a reference to a warning
 456      symbol.  WARNING is the warning to be issued.  SYMBOL is the name
 457      of the symbol which triggered the warning; it may be NULL if
 458      there is none.  ABFD, SECTION and ADDRESS identify the location
 459      which trigerred the warning; either ABFD or SECTION or both may
 460      be NULL if the location is not known.  */
 461   bfd_boolean (*warning)
 462     (struct bfd_link_info *, const char *warning, const char *symbol,
 463      bfd *abfd, asection *section, bfd_vma address);
 464   /* A function which is called when a relocation is attempted against
 465      an undefined symbol.  NAME is the symbol which is undefined.
 466      ABFD, SECTION and ADDRESS identify the location from which the
 467      reference is made. FATAL indicates whether an undefined symbol is
 468      a fatal error or not. In some cases SECTION may be NULL.  */
 469   bfd_boolean (*undefined_symbol)
 470     (struct bfd_link_info *, const char *name, bfd *abfd,
 471      asection *section, bfd_vma address, bfd_boolean fatal);
 472   /* A function which is called when a reloc overflow occurs.  NAME is
 473      the name of the symbol or section the reloc is against,
 474      RELOC_NAME is the name of the relocation, and ADDEND is any
 475      addend that is used.  ABFD, SECTION and ADDRESS identify the
 476      location at which the overflow occurs; if this is the result of a
 477      bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
 478      ABFD will be NULL.  */
 479   bfd_boolean (*reloc_overflow)
 480     (struct bfd_link_info *, const char *name, const char *reloc_name,
 481      bfd_vma addend, bfd *abfd, asection *section, bfd_vma address);
 482   /* A function which is called when a dangerous reloc is performed.
 483      The canonical example is an a29k IHCONST reloc which does not
 484      follow an IHIHALF reloc.  MESSAGE is an appropriate message.
 485      ABFD, SECTION and ADDRESS identify the location at which the
 486      problem occurred; if this is the result of a
 487      bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
 488      ABFD will be NULL.  */
 489   bfd_boolean (*reloc_dangerous)
 490     (struct bfd_link_info *, const char *message,
 491      bfd *abfd, asection *section, bfd_vma address);
 492   /* A function which is called when a reloc is found to be attached
 493      to a symbol which is not being written out.  NAME is the name of
 494      the symbol.  ABFD, SECTION and ADDRESS identify the location of
 495      the reloc; if this is the result of a
 496      bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
 497      ABFD will be NULL.  */
 498   bfd_boolean (*unattached_reloc)
 499     (struct bfd_link_info *, const char *name,
 500      bfd *abfd, asection *section, bfd_vma address);
 501   /* A function which is called when a symbol in notice_hash is
 502      defined or referenced.  NAME is the symbol.  ABFD, SECTION and
 503      ADDRESS are the value of the symbol.  If SECTION is
 504      bfd_und_section, this is a reference.  */
 505   bfd_boolean (*notice)
 506     (struct bfd_link_info *, const char *name,
 507      bfd *abfd, asection *section, bfd_vma address);
 508   /* A function which is called for reporting a linker error. ID is the
 509      error identifier. The remaining input is the same as einfo () in
 510      ld.  */
 511   bfd_boolean (*error_handler)
 512     (int id, const char *fmt, ...);
 513
 514 /* Identifiers of linker error messages used by error_handler.  */
 515 #define LD_DEFINITION_IN_DISCARDED_SECTION      1
 516 };
 517 \f
 518 /* The linker builds link_order structures which tell the code how to
 519    include input data in the output file.  */
 520
 521 /* These are the types of link_order structures.  */
 522
 523 enum bfd_link_order_type
 524 {
 525   bfd_undefined_link_order,     /* Undefined.  */
 526   bfd_indirect_link_order,      /* Built from a section.  */
 527   bfd_data_link_order,          /* Set to explicit data.  */
 528   bfd_section_reloc_link_order, /* Relocate against a section.  */
 529   bfd_symbol_reloc_link_order   /* Relocate against a symbol.  */
 530 };
 531
 532 /* This is the link_order structure itself.  These form a chain
 533    attached to the section whose contents they are describing.  */
 534
 535 struct bfd_link_order
 536 {
 537   /* Next link_order in chain.  */
 538   struct bfd_link_order *next;
 539   /* Type of link_order.  */
 540   enum bfd_link_order_type type;
 541   /* Offset within output section.  */
 542   bfd_vma offset;
 543   /* Size within output section.  */
 544   bfd_size_type size;
 545   /* Type specific information.  */
 546   union
 547     {
 548       struct
 549         {
 550           /* Section to include.  If this is used, then
 551              section->output_section must be the section the
 552              link_order is attached to, section->output_offset must
 553              equal the link_order offset field, and section->_raw_size
 554              must equal the link_order size field.  Maybe these
 555              restrictions should be relaxed someday.  */
 556           asection *section;
 557         } indirect;
 558       struct
 559         {
 560           /* Size of contents, or zero when contents size == size
 561              within output section.
 562              A non-zero value allows filling of the output section
 563              with an arbitrary repeated pattern.  */
 564           unsigned int size;
 565           /* Data to put into file.  */
 566           bfd_byte *contents;
 567         } data;
 568       struct
 569         {
 570           /* Description of reloc to generate.  Used for
 571              bfd_section_reloc_link_order and
 572              bfd_symbol_reloc_link_order.  */
 573           struct bfd_link_order_reloc *p;
 574         } reloc;
 575     } u;
 576 };
 577
 578 /* A linker order of type bfd_section_reloc_link_order or
 579    bfd_symbol_reloc_link_order means to create a reloc against a
 580    section or symbol, respectively.  This is used to implement -Ur to
 581    generate relocs for the constructor tables.  The
 582    bfd_link_order_reloc structure describes the reloc that BFD should
 583    create.  It is similar to a arelent, but I didn't use arelent
 584    because the linker does not know anything about most symbols, and
 585    any asymbol structure it creates will be partially meaningless.
 586    This information could logically be in the bfd_link_order struct,
 587    but I didn't want to waste the space since these types of relocs
 588    are relatively rare.  */
 589
 590 struct bfd_link_order_reloc
 591 {
 592   /* Reloc type.  */
 593   bfd_reloc_code_real_type reloc;
 594
 595   union
 596     {
 597       /* For type bfd_section_reloc_link_order, this is the section
 598          the reloc should be against.  This must be a section in the
 599          output BFD, not any of the input BFDs.  */
 600       asection *section;
 601       /* For type bfd_symbol_reloc_link_order, this is the name of the
 602          symbol the reloc should be against.  */
 603       const char *name;
 604     } u;
 605
 606   /* Addend to use.  The object file should contain zero.  The BFD
 607      backend is responsible for filling in the contents of the object
 608      file correctly.  For some object file formats (e.g., COFF) the
 609      addend must be stored into in the object file, and for some
 610      (e.g., SPARC a.out) it is kept in the reloc.  */
 611   bfd_vma addend;
 612 };
 613
 614 /* Allocate a new link_order for a section.  */
 615 extern struct bfd_link_order *bfd_new_link_order (bfd *, asection *);
 616
 617 /* These structures are used to describe version information for the
 618    ELF linker.  These structures could be manipulated entirely inside
 619    BFD, but it would be a pain.  Instead, the regular linker sets up
 620    these structures, and then passes them into BFD.  */
 621
 622 /* Glob pattern for a version.  */
 623
 624 struct bfd_elf_version_expr
 625 {
 626   /* Next glob pattern for this version.  */
 627   struct bfd_elf_version_expr *next;
 628   /* Glob pattern.  */
 629   const char *pattern;
 630   /* NULL for a glob pattern, otherwise a straight symbol.  */
 631   const char *symbol;
 632   /* Defined by ".symver".  */
 633   unsigned int symver : 1;
 634   /* Defined by version script.  */
 635   unsigned int script : 1;
 636   /* Pattern type.  */
 637 #define BFD_ELF_VERSION_C_TYPE          1
 638 #define BFD_ELF_VERSION_CXX_TYPE        2
 639 #define BFD_ELF_VERSION_JAVA_TYPE       4
 640   unsigned int mask : 3;
 641 };
 642
 643 struct bfd_elf_version_expr_head
 644 {
 645   /* List of all patterns, both wildcards and non-wildcards.  */
 646   struct bfd_elf_version_expr *list;
 647   /* Hash table for non-wildcards.  */
 648   void *htab;
 649   /* Remaining patterns.  */
 650   struct bfd_elf_version_expr *remaining;
 651   /* What kind of pattern types are present in list (bitmask).  */
 652   unsigned int mask;
 653 };
 654
 655 /* Version dependencies.  */
 656
 657 struct bfd_elf_version_deps
 658 {
 659   /* Next dependency for this version.  */
 660   struct bfd_elf_version_deps *next;
 661   /* The version which this version depends upon.  */
 662   struct bfd_elf_version_tree *version_needed;
 663 };
 664
 665 /* A node in the version tree.  */
 666
 667 struct bfd_elf_version_tree
 668 {
 669   /* Next version.  */
 670   struct bfd_elf_version_tree *next;
 671   /* Name of this version.  */
 672   const char *name;
 673   /* Version number.  */
 674   unsigned int vernum;
 675   /* Regular expressions for global symbols in this version.  */
 676   struct bfd_elf_version_expr_head globals;
 677   /* Regular expressions for local symbols in this version.  */
 678   struct bfd_elf_version_expr_head locals;
 679   /* List of versions which this version depends upon.  */
 680   struct bfd_elf_version_deps *deps;
 681   /* Index of the version name.  This is used within BFD.  */
 682   unsigned int name_indx;
 683   /* Whether this version tree was used.  This is used within BFD.  */
 684   int used;
 685   /* Matching hook.  */
 686   struct bfd_elf_version_expr *(*match)
 687     (struct bfd_elf_version_expr_head *head,
 688      struct bfd_elf_version_expr *prev, const char *sym);
 689 };
 690
 691 #endif