Subversion Repositories openrisc

/* BFD back-end data structures for ELF files.

   Copyright 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,

   2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010

   Free Software Foundation, Inc.

   Written by Cygnus Support.

   This file is part of BFD, the Binary File Descriptor library.

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3 of the License, or

   (at your option) any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program; if not, write to the Free Software

   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,

   MA 02110-1301, USA.  */

#ifndef _LIBELF_H_

#define _LIBELF_H_ 1

#include "elf/common.h"

#include "elf/external.h"

#include "elf/internal.h"

#include "bfdlink.h"

/* The number of entries in a section is its size divided by the size

   of a single entry.  This is normally only applicable to reloc and

   symbol table sections.

   PR 9934: It is possible to have relocations that do not refer to

   symbols, thus it is also possible to have a relocation section in

   an object file, but no symbol table.  */

#define NUM_SHDR_ENTRIES(shdr) ((shdr)->sh_entsize > 0 ? (shdr)->sh_size / (shdr)->sh_entsize : 0)

/* If size isn't specified as 64 or 32, NAME macro should fail.  */

#ifndef NAME

#if ARCH_SIZE == 64

#define NAME(x, y) x ## 64 ## _ ## y

#endif

#if ARCH_SIZE == 32

#define NAME(x, y) x ## 32 ## _ ## y

#endif

#endif

#ifndef NAME

#define NAME(x, y) x ## NOSIZE ## _ ## y

#endif

#define ElfNAME(X)      NAME(Elf,X)

#define elfNAME(X)      NAME(elf,X)

/* Information held for an ELF symbol.  The first field is the

   corresponding asymbol.  Every symbol is an ELF file is actually a

   pointer to this structure, although it is often handled as a

   pointer to an asymbol.  */

typedef struct

{

  /* The BFD symbol.  */

  asymbol symbol;

  /* ELF symbol information.  */

  Elf_Internal_Sym internal_elf_sym;

  /* Backend specific information.  */

  union

    {

      unsigned int hppa_arg_reloc;

      void *mips_extr;

      void *any;

    }

  tc_data;

  /* Version information.  This is from an Elf_Internal_Versym

     structure in a SHT_GNU_versym section.  It is zero if there is no

     version information.  */

  unsigned short version;

} elf_symbol_type;

struct elf_strtab_hash;

struct got_entry;

struct plt_entry;

union gotplt_union

  {

    bfd_signed_vma refcount;

    bfd_vma offset;

    struct got_entry *glist;

    struct plt_entry *plist;

  };

struct elf_link_virtual_table_entry

  {

    /* Virtual table entry use information.  This array is nominally of size

       size/sizeof(target_void_pointer), though we have to be able to assume

       and track a size while the symbol is still undefined.  It is indexed

       via offset/sizeof(target_void_pointer).  */

    size_t size;

    bfd_boolean *used;

    /* Virtual table derivation info.  */

    struct elf_link_hash_entry *parent;

  };

/* ELF linker hash table entries.  */

struct elf_link_hash_entry

{

  struct bfd_link_hash_entry root;

  /* Symbol index in output file.  This is initialized to -1.  It is

     set to -2 if the symbol is used by a reloc.  */

  long indx;

  /* Symbol index as a dynamic symbol.  Initialized to -1, and remains

     -1 if this is not a dynamic symbol.  */

  /* ??? Note that this is consistently used as a synonym for tests

     against whether we can perform various simplifying transformations

     to the code.  (E.g. changing a pc-relative jump to a PLT entry

     into a pc-relative jump to the target function.)  That test, which

     is often relatively complex, and someplaces wrong or incomplete,

     should really be replaced by a predicate in elflink.c.

     End result: this field -1 does not indicate that the symbol is

     not in the dynamic symbol table, but rather that the symbol is

     not visible outside this DSO.  */

  long dynindx;

  /* If this symbol requires an entry in the global offset table, the

     processor specific backend uses this field to track usage and

     final offset.  Two schemes are supported:  The first assumes that

     a symbol may only have one GOT entry, and uses REFCOUNT until

     size_dynamic_sections, at which point the contents of the .got is

     fixed.  Afterward, if OFFSET is -1, then the symbol does not

     require a global offset table entry.  The second scheme allows

     multiple GOT entries per symbol, managed via a linked list

     pointed to by GLIST.  */

  union gotplt_union got;

  /* Same, but tracks a procedure linkage table entry.  */

  union gotplt_union plt;

  /* Symbol size.  */

  bfd_size_type size;

  /* Symbol type (STT_NOTYPE, STT_OBJECT, etc.).  */

  unsigned int type : 8;

  /* Symbol st_other value, symbol visibility.  */

  unsigned int other : 8;

  /* Symbol is referenced by a non-shared object (other than the object

     in which it is defined).  */

  unsigned int ref_regular : 1;

  /* Symbol is defined by a non-shared object.  */

  unsigned int def_regular : 1;

  /* Symbol is referenced by a shared object.  */

  unsigned int ref_dynamic : 1;

  /* Symbol is defined by a shared object.  */

  unsigned int def_dynamic : 1;

  /* Symbol has a non-weak reference from a non-shared object (other than

     the object in which it is defined).  */

  unsigned int ref_regular_nonweak : 1;

  /* Dynamic symbol has been adjustd.  */

  unsigned int dynamic_adjusted : 1;

  /* Symbol needs a copy reloc.  */

  unsigned int needs_copy : 1;

  /* Symbol needs a procedure linkage table entry.  */

  unsigned int needs_plt : 1;

  /* Symbol appears in a non-ELF input file.  */

  unsigned int non_elf : 1;

  /* Symbol should be marked as hidden in the version information.  */

  unsigned int hidden : 1;

  /* Symbol was forced to local scope due to a version script file.  */

  unsigned int forced_local : 1;

  /* Symbol was forced to be dynamic due to a version script file.  */

  unsigned int dynamic : 1;

  /* Symbol was marked during garbage collection.  */

  unsigned int mark : 1;

  /* Symbol is referenced by a non-GOT/non-PLT relocation.  This is

     not currently set by all the backends.  */

  unsigned int non_got_ref : 1;

  /* Symbol has a definition in a shared object.

     FIXME: There is no real need for this field if def_dynamic is never

     cleared and all places that test def_dynamic also test def_regular.  */

  unsigned int dynamic_def : 1;

  /* Symbol is weak in all shared objects.  */

  unsigned int dynamic_weak : 1;

  /* Symbol is referenced with a relocation where C/C++ pointer equality

     matters.  */

  unsigned int pointer_equality_needed : 1;

  /* Symbol is a unique global symbol.  */

  unsigned int unique_global : 1;

  /* String table index in .dynstr if this is a dynamic symbol.  */

  unsigned long dynstr_index;

  union

  {

    /* If this is a weak defined symbol from a dynamic object, this

       field points to a defined symbol with the same value, if there is

       one.  Otherwise it is NULL.  */

    struct elf_link_hash_entry *weakdef;

    /* Hash value of the name computed using the ELF hash function.

       Used part way through size_dynamic_sections, after we've finished

       with weakdefs.  */

    unsigned long elf_hash_value;

  } u;

  /* Version information.  */

  union

  {

    /* This field is used for a symbol which is not defined in a

       regular object.  It points to the version information read in

       from the dynamic object.  */

    Elf_Internal_Verdef *verdef;

    /* This field is used for a symbol which is defined in a regular

       object.  It is set up in size_dynamic_sections.  It points to

       the version information we should write out for this symbol.  */

    struct bfd_elf_version_tree *vertree;

  } verinfo;

  struct elf_link_virtual_table_entry *vtable;

};

/* Will references to this symbol always reference the symbol

   in this object?  STV_PROTECTED is excluded from the visibility test

   here so that function pointer comparisons work properly.  Since

   function symbols not defined in an app are set to their .plt entry,

   it's necessary for shared libs to also reference the .plt even

   though the symbol is really local to the shared lib.  */

#define SYMBOL_REFERENCES_LOCAL(INFO, H) \

  _bfd_elf_symbol_refs_local_p (H, INFO, 0)

/* Will _calls_ to this symbol always call the version in this object?  */

#define SYMBOL_CALLS_LOCAL(INFO, H) \

  _bfd_elf_symbol_refs_local_p (H, INFO, 1)

/* Common symbols that are turned into definitions don't have the

   DEF_REGULAR flag set, so they might appear to be undefined.  */

#define ELF_COMMON_DEF_P(H) \

  (!(H)->def_regular                                                    \

   && !(H)->def_dynamic                                                 \

   && (H)->root.type == bfd_link_hash_defined)

/* Records local symbols to be emitted in the dynamic symbol table.  */

struct elf_link_local_dynamic_entry

{

  struct elf_link_local_dynamic_entry *next;

  /* The input bfd this symbol came from.  */

  bfd *input_bfd;

  /* The index of the local symbol being copied.  */

  long input_indx;

  /* The index in the outgoing dynamic symbol table.  */

  long dynindx;

  /* A copy of the input symbol.  */

  Elf_Internal_Sym isym;

};

struct elf_link_loaded_list

{

  struct elf_link_loaded_list *next;

  bfd *abfd;

};

/* Structures used by the eh_frame optimization code.  */

struct eh_cie_fde

{

  union {

    struct {

      /* If REMOVED == 1, this is the CIE that the FDE originally used.

         The CIE belongs to the same .eh_frame input section as the FDE.

         If REMOVED == 0, this is the CIE that we have chosen to use for

         the output FDE.  The CIE's REMOVED field is also 0, but the CIE

         might belong to a different .eh_frame input section from the FDE.  */

      struct eh_cie_fde *cie_inf;

      struct eh_cie_fde *next_for_section;

    } fde;

    struct {

      /* CIEs have three states:

         - REMOVED && !MERGED: Slated for removal because we haven't yet

           proven that an FDE needs it.  FULL_CIE, if nonnull, points to

           more detailed information about the CIE.

         - REMOVED && MERGED: We have merged this CIE with MERGED_WITH,

           which may not belong to the same input section.

         - !REMOVED: We have decided to keep this CIE.  SEC is the

           .eh_frame input section that contains the CIE.  */

      union {

        struct cie *full_cie;

        struct eh_cie_fde *merged_with;

        asection *sec;

      } u;

      /* The offset of the personality data from the start of the CIE,

         or 0 if the CIE doesn't have any.  */

      unsigned int personality_offset : 8;

      /* True if we have marked relocations associated with this CIE.  */

      unsigned int gc_mark : 1;

      /* True if we have decided to turn an absolute LSDA encoding into

         a PC-relative one.  */

      unsigned int make_lsda_relative : 1;

      /* True if we have decided to turn an absolute personality

         encoding into a PC-relative one.  */

      unsigned int make_per_encoding_relative : 1;

      /* True if the CIE contains personality data and if that

         data uses a PC-relative encoding.  Always true when

         make_per_encoding_relative is.  */

      unsigned int per_encoding_relative : 1;

      /* True if we need to add an 'R' (FDE encoding) entry to the

         CIE's augmentation data.  */

      unsigned int add_fde_encoding : 1;

      /* True if we have merged this CIE with another.  */

      unsigned int merged : 1;

      /* Unused bits.  */

      unsigned int pad1 : 18;

    } cie;

  } u;

  unsigned int reloc_index;

  unsigned int size;

  unsigned int offset;

  unsigned int new_offset;

  unsigned int fde_encoding : 8;

  unsigned int lsda_encoding : 8;

  unsigned int lsda_offset : 8;

  /* True if this entry represents a CIE, false if it represents an FDE.  */

  unsigned int cie : 1;

  /* True if this entry is currently marked for removal.  */

  unsigned int removed : 1;

  /* True if we need to add a 'z' (augmentation size) entry to the CIE's

     augmentation data, and an associated byte to each of the CIE's FDEs.  */

  unsigned int add_augmentation_size : 1;

  /* True if we have decided to convert absolute FDE relocations into

     relative ones.  This applies to the first relocation in the FDE,

     which is against the code that the FDE describes.  */

  unsigned int make_relative : 1;

  /* Unused bits.  */

  unsigned int pad1 : 4;

  unsigned int *set_loc;

};

struct eh_frame_sec_info

{

  unsigned int count;

  struct cie *cies;

  struct eh_cie_fde entry[1];

};

struct eh_frame_array_ent

{

  bfd_vma initial_loc;

  bfd_vma fde;

};

struct htab;

struct eh_frame_hdr_info

{

  struct htab *cies;

  asection *hdr_sec;

  unsigned int fde_count, array_count;

  struct eh_frame_array_ent *array;

  /* TRUE if we should try to merge CIEs between input sections.  */

  bfd_boolean merge_cies;

  /* TRUE if all .eh_frames have been parsd.  */

  bfd_boolean parsed_eh_frames;

  /* TRUE if .eh_frame_hdr should contain the sorted search table.

     We build it if we successfully read all .eh_frame input sections

     and recognize them.  */

  bfd_boolean table;

};

/* Enum used to identify target specific extensions to the elf_obj_tdata

   and elf_link_hash_table structures.  Note the enums deliberately start

   from 1 so that we can detect an uninitialized field.  The generic value

   is last so that additions to this enum do not need to modify more than

   one line.  */

enum elf_target_id

{

  ALPHA_ELF_DATA = 1,

  ARM_ELF_DATA,

  AVR_ELF_DATA,

  BFIN_ELF_DATA,

  CRIS_ELF_DATA,

  FRV_ELF_DATA,

  HPPA32_ELF_DATA,

  HPPA64_ELF_DATA,

  I386_ELF_DATA,

  IA64_ELF_DATA,

  LM32_ELF_DATA,

  M32R_ELF_DATA,

  M68HC11_ELF_DATA,

  M68K_ELF_DATA,

  MICROBLAZE_ELF_DATA,

  MIPS_ELF_DATA,

  MN10300_ELF_DATA,

  PPC32_ELF_DATA,

  PPC64_ELF_DATA,

  S390_ELF_DATA,

  SH_ELF_DATA,

  SPARC_ELF_DATA,

  SPU_ELF_DATA,

  TIC6X_ELF_DATA,

  X86_64_ELF_DATA,

  XTENSA_ELF_DATA,

  GENERIC_ELF_DATA

};

/* ELF linker hash table.  */

struct elf_link_hash_table

{

  struct bfd_link_hash_table root;

  /* An identifier used to distinguish different target

     specific extensions to this structure.  */

  enum elf_target_id hash_table_id;

  /* Whether we have created the special dynamic sections required

     when linking against or generating a shared object.  */

  bfd_boolean dynamic_sections_created;

  /* True if this target has relocatable executables, so needs dynamic

     section symbols.  */

  bfd_boolean is_relocatable_executable;

  /* The BFD used to hold special sections created by the linker.

     This will be the first BFD found which requires these sections to

     be created.  */

  bfd *dynobj;

  /* The value to use when initialising got.refcount/offset and

     plt.refcount/offset in an elf_link_hash_entry.  Set to zero when

     the values are refcounts.  Set to init_got_offset/init_plt_offset

     in size_dynamic_sections when the values may be offsets.  */

  union gotplt_union init_got_refcount;

  union gotplt_union init_plt_refcount;

  /* The value to use for got.refcount/offset and plt.refcount/offset

     when the values may be offsets.  Normally (bfd_vma) -1.  */

  union gotplt_union init_got_offset;

  union gotplt_union init_plt_offset;

  /* The number of symbols found in the link which must be put into

     the .dynsym section.  */

  bfd_size_type dynsymcount;

  /* The string table of dynamic symbols, which becomes the .dynstr

     section.  */

  struct elf_strtab_hash *dynstr;

  /* The number of buckets in the hash table in the .hash section.

     This is based on the number of dynamic symbols.  */

  bfd_size_type bucketcount;

  /* A linked list of DT_NEEDED names found in dynamic objects

     included in the link.  */

  struct bfd_link_needed_list *needed;

  /* Sections in the output bfd that provides a section symbol

     to be used by relocations emitted against local symbols.

     Most targets will not use data_index_section.  */

  asection *text_index_section;

  asection *data_index_section;

  /* The _GLOBAL_OFFSET_TABLE_ symbol.  */

  struct elf_link_hash_entry *hgot;

  /* The _PROCEDURE_LINKAGE_TABLE_ symbol.  */

  struct elf_link_hash_entry *hplt;

  /* A pointer to information used to merge SEC_MERGE sections.  */

  void *merge_info;

  /* Used to link stabs in sections.  */

  struct stab_info stab_info;

  /* Used by eh_frame code when editing .eh_frame.  */

  struct eh_frame_hdr_info eh_info;

  /* A linked list of local symbols to be added to .dynsym.  */

  struct elf_link_local_dynamic_entry *dynlocal;

  /* A linked list of DT_RPATH/DT_RUNPATH names found in dynamic

     objects included in the link.  */

  struct bfd_link_needed_list *runpath;

  /* Cached first output tls section and size of PT_TLS segment.  */

  asection *tls_sec;

  bfd_size_type tls_size;

  /* A linked list of BFD's loaded in the link.  */

  struct elf_link_loaded_list *loaded;

  /* Short-cuts to get to dynamic linker sections.  */

  asection *sgot;

  asection *sgotplt;

  asection *srelgot;

  asection *splt;

  asection *srelplt;

  asection *igotplt;

  asection *iplt;

  asection *irelplt;

  asection *irelifunc;

};

/* Look up an entry in an ELF linker hash table.  */

#define elf_link_hash_lookup(table, string, create, copy, follow)       \

  ((struct elf_link_hash_entry *)                                       \

   bfd_link_hash_lookup (&(table)->root, (string), (create),            \

                         (copy), (follow)))

/* Traverse an ELF linker hash table.  */

#define elf_link_hash_traverse(table, func, info)                       \

  (bfd_link_hash_traverse                                               \

   (&(table)->root,                                                     \

    (bfd_boolean (*) (struct bfd_link_hash_entry *, void *)) (func),    \

    (info)))

/* Get the ELF linker hash table from a link_info structure.  */

#define elf_hash_table(p) ((struct elf_link_hash_table *) ((p)->hash))

#define elf_hash_table_id(table)        ((table) -> hash_table_id)

/* Returns TRUE if the hash table is a struct elf_link_hash_table.  */

#define is_elf_hash_table(htab)                                         \

  (((struct bfd_link_hash_table *) (htab))->type == bfd_link_elf_hash_table)

/* Used by bfd_sym_from_r_symndx to cache a small number of local

   symbols.  */

#define LOCAL_SYM_CACHE_SIZE 32

struct sym_cache

{

  bfd *abfd;

  unsigned long indx[LOCAL_SYM_CACHE_SIZE];

  Elf_Internal_Sym sym[LOCAL_SYM_CACHE_SIZE];

};

/* Constant information held for an ELF backend.  */

struct elf_size_info {

  unsigned char sizeof_ehdr, sizeof_phdr, sizeof_shdr;

  unsigned char sizeof_rel, sizeof_rela, sizeof_sym, sizeof_dyn, sizeof_note;

  /* The size of entries in the .hash section.  */

  unsigned char sizeof_hash_entry;

  /* The number of internal relocations to allocate per external

     relocation entry.  */

  unsigned char int_rels_per_ext_rel;

  /* We use some fixed size arrays.  This should be large enough to

     handle all back-ends.  */

#define MAX_INT_RELS_PER_EXT_REL 3

  unsigned char arch_size, log_file_align;

  unsigned char elfclass, ev_current;

  int (*write_out_phdrs)

    (bfd *, const Elf_Internal_Phdr *, unsigned int);

  bfd_boolean

    (*write_shdrs_and_ehdr) (bfd *);

  bfd_boolean (*checksum_contents)

    (bfd * , void (*) (const void *, size_t, void *), void *);

  void (*write_relocs)

    (bfd *, asection *, void *);

  bfd_boolean (*swap_symbol_in)

    (bfd *, const void *, const void *, Elf_Internal_Sym *);

  void (*swap_symbol_out)

    (bfd *, const Elf_Internal_Sym *, void *, void *);

  bfd_boolean (*slurp_reloc_table)

    (bfd *, asection *, asymbol **, bfd_boolean);

  long (*slurp_symbol_table)

    (bfd *, asymbol **, bfd_boolean);

  void (*swap_dyn_in)

    (bfd *, const void *, Elf_Internal_Dyn *);

  void (*swap_dyn_out)

    (bfd *, const Elf_Internal_Dyn *, void *);

  /* This function is called to swap in a REL relocation.  If an

     external relocation corresponds to more than one internal

     relocation, then all relocations are swapped in at once.  */

  void (*swap_reloc_in)

    (bfd *, const bfd_byte *, Elf_Internal_Rela *);

  /* This function is called to swap out a REL relocation.  */

  void (*swap_reloc_out)

    (bfd *, const Elf_Internal_Rela *, bfd_byte *);

  /* This function is called to swap in a RELA relocation.  If an

     external relocation corresponds to more than one internal

     relocation, then all relocations are swapped in at once.  */

  void (*swap_reloca_in)

    (bfd *, const bfd_byte *, Elf_Internal_Rela *);

  /* This function is called to swap out a RELA relocation.  */

  void (*swap_reloca_out)

    (bfd *, const Elf_Internal_Rela *, bfd_byte *);

};

#define elf_symbol_from(ABFD,S) \

        (((S)->the_bfd->xvec->flavour == bfd_target_elf_flavour \

          && (S)->the_bfd->tdata.elf_obj_data != 0) \

         ? (elf_symbol_type *) (S) \

         : 0)

enum elf_reloc_type_class {

  reloc_class_normal,

  reloc_class_relative,

  reloc_class_plt,

  reloc_class_copy

};

struct elf_reloc_cookie

{

  Elf_Internal_Rela *rels, *rel, *relend;

  Elf_Internal_Sym *locsyms;

  bfd *abfd;

  size_t locsymcount;

  size_t extsymoff;

  struct elf_link_hash_entry **sym_hashes;

  int r_sym_shift;

  bfd_boolean bad_symtab;

};

/* The level of IRIX compatibility we're striving for.  */

typedef enum {

  ict_none,

  ict_irix5,

  ict_irix6

} irix_compat_t;

/* Mapping of ELF section names and types.  */

struct bfd_elf_special_section

{

  const char *prefix;

  int prefix_length;

  /* 0 means name must match PREFIX exactly.

     -1 means name must start with PREFIX followed by an arbitrary string.

     -2 means name must match PREFIX exactly or consist of PREFIX followed

     by a dot then anything.

     > 0 means name must start with the first PREFIX_LENGTH chars of

     PREFIX and finish with the last SUFFIX_LENGTH chars of PREFIX.  */

  int suffix_length;

  int type;

  bfd_vma attr;

};

enum action_discarded

  {

    COMPLAIN = 1,

    PRETEND = 2

  };

typedef asection * (*elf_gc_mark_hook_fn)

  (asection *, struct bfd_link_info *, Elf_Internal_Rela *,

   struct elf_link_hash_entry *, Elf_Internal_Sym *);

struct elf_backend_data

{

  /* The architecture for this backend.  */

  enum bfd_architecture arch;

  /* The ELF machine code (EM_xxxx) for this backend.  */

  int elf_machine_code;

  /* EI_OSABI. */

  int elf_osabi;

  /* The maximum page size for this backend.  */

  bfd_vma maxpagesize;

  /* The minimum page size for this backend.  An input object will not be

     considered page aligned unless its sections are correctly aligned for

     pages at least this large.  May be smaller than maxpagesize.  */

  bfd_vma minpagesize;

  /* The common page size for this backend.  */

  bfd_vma commonpagesize;

  /* The BFD flags applied to sections created for dynamic linking.  */

  flagword dynamic_sec_flags;

  /* A function to translate an ELF RELA relocation to a BFD arelent

     structure.  */

  void (*elf_info_to_howto)

    (bfd *, arelent *, Elf_Internal_Rela *);

  /* A function to translate an ELF REL relocation to a BFD arelent

     structure.  */

  void (*elf_info_to_howto_rel)

    (bfd *, arelent *, Elf_Internal_Rela *);

  /* A function to determine whether a symbol is global when

     partitioning the symbol table into local and global symbols.

     This should be NULL for most targets, in which case the correct

     thing will be done.  MIPS ELF, at least on the Irix 5, has

     special requirements.  */

  bfd_boolean (*elf_backend_sym_is_global)

    (bfd *, asymbol *);

  /* The remaining functions are hooks which are called only if they

     are not NULL.  */

  /* A function to permit a backend specific check on whether a

     particular BFD format is relevant for an object file, and to

     permit the backend to set any global information it wishes.  When

     this is called elf_elfheader is set, but anything else should be

     used with caution.  If this returns FALSE, the check_format

     routine will return a bfd_error_wrong_format error.  */

  bfd_boolean (*elf_backend_object_p)

    (bfd *);

  /* A function to do additional symbol processing when reading the

     ELF symbol table.  This is where any processor-specific special

     section indices are handled.  */

  void (*elf_backend_symbol_processing)

    (bfd *, asymbol *);

  /* A function to do additional symbol processing after reading the

     entire ELF symbol table.  */

  bfd_boolean (*elf_backend_symbol_table_processing)

    (bfd *, elf_symbol_type *, unsigned int);

  /* A function to set the type of the info field.  Processor-specific

     types should be handled here.  */

  int (*elf_backend_get_symbol_type)

    (Elf_Internal_Sym *, int);

  /* A function to return the linker hash table entry of a symbol that

     might be satisfied by an archive symbol.  */

  struct elf_link_hash_entry * (*elf_backend_archive_symbol_lookup)

    (bfd *, struct bfd_link_info *, const char *);

  /* Return true if local section symbols should have a non-null st_name.

     NULL implies false.  */

  bfd_boolean (*elf_backend_name_local_section_symbols)

    (bfd *);

  /* A function to do additional processing on the ELF section header

     just before writing it out.  This is used to set the flags and

     type fields for some sections, or to actually write out data for

     unusual sections.  */

  bfd_boolean (*elf_backend_section_processing)

    (bfd *, Elf_Internal_Shdr *);