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2.1 typedef bfd

A BFD has type bfd; objects of this type are the cornerstone of any application using BFD. Using BFD consists of making references though the BFD and to data in the BFD.

Here is the structure that defines the type bfd. It contains the major data about the file and pointers to the rest of the data.

enum bfd_direction
    no_direction = 0,
    read_direction = 1,
    write_direction = 2,
    both_direction = 3

enum bfd_plugin_format
    bfd_plugin_unknown = 0,
    bfd_plugin_yes = 1,
    bfd_plugin_no = 2

struct bfd_build_id
    bfd_size_type size;
    bfd_byte data[1];

struct bfd
  /* The filename the application opened the BFD with.  */
  const char *filename;

  /* A pointer to the target jump table.  */
  const struct bfd_target *xvec;

  /* The IOSTREAM, and corresponding IO vector that provide access
     to the file backing the BFD.  */
  void *iostream;
  const struct bfd_iovec *iovec;

  /* The caching routines use these to maintain a
     least-recently-used list of BFDs.  */
  struct bfd *lru_prev, *lru_next;

  /* Track current file position (or current buffer offset for
     in-memory BFDs).  When a file is closed by the caching routines,
     BFD retains state information on the file here.  */
  ufile_ptr where;

  /* File modified time, if mtime_set is TRUE.  */
  long mtime;

  /* A unique identifier of the BFD  */
  unsigned int id;

  /* Format_specific flags.  */
  flagword flags;

  /* Values that may appear in the flags field of a BFD.  These also
     appear in the object_flags field of the bfd_target structure, where
     they indicate the set of flags used by that backend (not all flags
     are meaningful for all object file formats) (FIXME: at the moment,
     the object_flags values have mostly just been copied from backend
     to another, and are not necessarily correct).  */

#define BFD_NO_FLAGS                0x0

  /* BFD contains relocation entries.  */
#define HAS_RELOC                   0x1

  /* BFD is directly executable.  */
#define EXEC_P                      0x2

  /* BFD has line number information (basically used for F_LNNO in a
     COFF header).  */
#define HAS_LINENO                  0x4

  /* BFD has debugging information.  */
#define HAS_DEBUG                  0x08

  /* BFD has symbols.  */
#define HAS_SYMS                   0x10

  /* BFD has local symbols (basically used for F_LSYMS in a COFF
     header).  */
#define HAS_LOCALS                 0x20

  /* BFD is a dynamic object.  */
#define DYNAMIC                    0x40

  /* Text section is write protected (if D_PAGED is not set, this is
     like an a.out NMAGIC file) (the linker sets this by default, but
     clears it for -r or -N).  */
#define WP_TEXT                    0x80

  /* BFD is dynamically paged (this is like an a.out ZMAGIC file) (the
     linker sets this by default, but clears it for -r or -n or -N).  */
#define D_PAGED                   0x100

  /* BFD is relaxable (this means that bfd_relax_section may be able to
     do something) (sometimes bfd_relax_section can do something even if
     this is not set).  */
#define BFD_IS_RELAXABLE          0x200

  /* This may be set before writing out a BFD to request using a
     traditional format.  For example, this is used to request that when
     writing out an a.out object the symbols not be hashed to eliminate
     duplicates.  */

  /* This flag indicates that the BFD contents are actually cached
     in memory.  If this is set, iostream points to a bfd_in_memory
     struct.  */
#define BFD_IN_MEMORY             0x800

  /* This BFD has been created by the linker and doesn't correspond
     to any input file.  */
#define BFD_LINKER_CREATED       0x1000

  /* This may be set before writing out a BFD to request that it
     be written using values for UIDs, GIDs, timestamps, etc. that
     will be consistent from run to run.  */

  /* Compress sections in this BFD.  */
#define BFD_COMPRESS             0x4000

  /* Decompress sections in this BFD.  */
#define BFD_DECOMPRESS           0x8000

  /* BFD is a dummy, for plugins.  */
#define BFD_PLUGIN              0x10000

  /* Compress sections in this BFD with SHF_COMPRESSED from gABI.  */
#define BFD_COMPRESS_GABI       0x20000

  /* Convert ELF common symbol type to STT_COMMON or STT_OBJECT in this
     BFD.  */
#define BFD_CONVERT_ELF_COMMON  0x40000

  /* Use the ELF STT_COMMON type in this BFD.  */
#define BFD_USE_ELF_STT_COMMON  0x80000

  /* Put pathnames into archives (non-POSIX).  */
#define BFD_ARCHIVE_FULL_PATH  0x100000

  /* Flags bits to be saved in bfd_preserve_save.  */

  /* Flags bits which are for BFD use only.  */

  /* The format which belongs to the BFD. (object, core, etc.)  */
  ENUM_BITFIELD (bfd_format) format : 3;

  /* The direction with which the BFD was opened.  */
  ENUM_BITFIELD (bfd_direction) direction : 2;

  /* Is the file descriptor being cached?  That is, can it be closed as
     needed, and re-opened when accessed later?  */
  unsigned int cacheable : 1;

  /* Marks whether there was a default target specified when the
     BFD was opened. This is used to select which matching algorithm
     to use to choose the back end.  */
  unsigned int target_defaulted : 1;

  /* ... and here: (``once'' means at least once).  */
  unsigned int opened_once : 1;

  /* Set if we have a locally maintained mtime value, rather than
     getting it from the file each time.  */
  unsigned int mtime_set : 1;

  /* Flag set if symbols from this BFD should not be exported.  */
  unsigned int no_export : 1;

  /* Remember when output has begun, to stop strange things
     from happening.  */
  unsigned int output_has_begun : 1;

  /* Have archive map.  */
  unsigned int has_armap : 1;

  /* Set if this is a thin archive.  */
  unsigned int is_thin_archive : 1;

  /* Set if this archive should not cache element positions.  */
  unsigned int no_element_cache : 1;

  /* Set if only required symbols should be added in the link hash table for
     this object.  Used by VMS linkers.  */
  unsigned int selective_search : 1;

  /* Set if this is the linker output BFD.  */
  unsigned int is_linker_output : 1;

  /* Set if this is the linker input BFD.  */
  unsigned int is_linker_input : 1;

  /* If this is an input for a compiler plug-in library.  */
  ENUM_BITFIELD (bfd_plugin_format) plugin_format : 2;

  /* Set if this is a plugin output file.  */
  unsigned int lto_output : 1;

  /* Set if this is a slim LTO object not loaded with a compiler plugin.  */
  unsigned int lto_slim_object : 1;

  /* Do not attempt to modify this file.  Set when detecting errors
     that BFD is not prepared to handle for objcopy/strip.  */
  unsigned int read_only : 1;

  /* Set to dummy BFD created when claimed by a compiler plug-in
     library.  */
  bfd *plugin_dummy_bfd;

  /* The offset of this bfd in the file, typically 0 if it is not
     contained in an archive.  */
  ufile_ptr origin;

  /* The origin in the archive of the proxy entry.  This will
     normally be the same as origin, except for thin archives,
     when it will contain the current offset of the proxy in the
     thin archive rather than the offset of the bfd in its actual
     container.  */
  ufile_ptr proxy_origin;

  /* A hash table for section names.  */
  struct bfd_hash_table section_htab;

  /* Pointer to linked list of sections.  */
  struct bfd_section *sections;

  /* The last section on the section list.  */
  struct bfd_section *section_last;

  /* The number of sections.  */
  unsigned int section_count;

  /* A field used by _bfd_generic_link_add_archive_symbols.  This will
     be used only for archive elements.  */
  int archive_pass;

  /* Stuff only useful for object files:
     The start address.  */
  bfd_vma start_address;

  /* Symbol table for output BFD (with symcount entries).
     Also used by the linker to cache input BFD symbols.  */
  struct bfd_symbol **outsymbols;

  /* Used for input and output.  */
  unsigned int symcount;

  /* Used for slurped dynamic symbol tables.  */
  unsigned int dynsymcount;

  /* Pointer to structure which contains architecture information.  */
  const struct bfd_arch_info *arch_info;

  /* Cached length of file for bfd_get_size.  0 until bfd_get_size is
     called, 1 if stat returns an error or the file size is too large to
     return in ufile_ptr.  Both 0 and 1 should be treated as "unknown".  */
  ufile_ptr size;

  /* Stuff only useful for archives.  */
  void *arelt_data;
  struct bfd *my_archive;      /* The containing archive BFD.  */
  struct bfd *archive_next;    /* The next BFD in the archive.  */
  struct bfd *archive_head;    /* The first BFD in the archive.  */
  struct bfd *nested_archives; /* List of nested archive in a flattened
                                  thin archive.  */

  union {
    /* For input BFDs, a chain of BFDs involved in a link.  */
    struct bfd *next;
    /* For output BFD, the linker hash table.  */
    struct bfd_link_hash_table *hash;
  } link;

  /* Used by the back end to hold private data.  */
      struct aout_data_struct *aout_data;
      struct artdata *aout_ar_data;
      struct coff_tdata *coff_obj_data;
      struct pe_tdata *pe_obj_data;
      struct xcoff_tdata *xcoff_obj_data;
      struct ecoff_tdata *ecoff_obj_data;
      struct srec_data_struct *srec_data;
      struct verilog_data_struct *verilog_data;
      struct ihex_data_struct *ihex_data;
      struct tekhex_data_struct *tekhex_data;
      struct elf_obj_tdata *elf_obj_data;
      struct mmo_data_struct *mmo_data;
      struct sun_core_struct *sun_core_data;
      struct sco5_core_struct *sco5_core_data;
      struct trad_core_struct *trad_core_data;
      struct som_data_struct *som_data;
      struct hpux_core_struct *hpux_core_data;
      struct hppabsd_core_struct *hppabsd_core_data;
      struct sgi_core_struct *sgi_core_data;
      struct lynx_core_struct *lynx_core_data;
      struct osf_core_struct *osf_core_data;
      struct cisco_core_struct *cisco_core_data;
      struct versados_data_struct *versados_data;
      struct netbsd_core_struct *netbsd_core_data;
      struct mach_o_data_struct *mach_o_data;
      struct mach_o_fat_data_struct *mach_o_fat_data;
      struct plugin_data_struct *plugin_data;
      struct bfd_pef_data_struct *pef_data;
      struct bfd_pef_xlib_data_struct *pef_xlib_data;
      struct bfd_sym_data_struct *sym_data;
      void *any;

  /* Used by the application to hold private data.  */
  void *usrdata;

  /* Where all the allocated stuff under this BFD goes.  This is a
     struct objalloc *, but we use void * to avoid requiring the inclusion
     of objalloc.h.  */
  void *memory;

  /* For input BFDs, the build ID, if the object has one. */
  const struct bfd_build_id *build_id;

static inline const char *
bfd_get_filename (const bfd *abfd)
  return abfd->filename;

static inline bfd_boolean
bfd_get_cacheable (const bfd *abfd)
  return abfd->cacheable;

static inline enum bfd_format
bfd_get_format (const bfd *abfd)
  return abfd->format;

static inline flagword
bfd_get_file_flags (const bfd *abfd)
  return abfd->flags;

static inline bfd_vma
bfd_get_start_address (const bfd *abfd)
  return abfd->start_address;

static inline unsigned int
bfd_get_symcount (const bfd *abfd)
  return abfd->symcount;

static inline unsigned int
bfd_get_dynamic_symcount (const bfd *abfd)
  return abfd->dynsymcount;

static inline struct bfd_symbol **
bfd_get_outsymbols (const bfd *abfd)
  return abfd->outsymbols;

static inline unsigned int
bfd_count_sections (const bfd *abfd)
  return abfd->section_count;

static inline bfd_boolean
bfd_has_map (const bfd *abfd)
  return abfd->has_armap;

static inline bfd_boolean
bfd_is_thin_archive (const bfd *abfd)
  return abfd->is_thin_archive;

static inline void *
bfd_usrdata (const bfd *abfd)
  return abfd->usrdata;

/* See note beside bfd_set_section_userdata.  */
static inline bfd_boolean
bfd_set_cacheable (bfd * abfd, bfd_boolean val)
  abfd->cacheable = val;
  return TRUE;

static inline void
bfd_set_thin_archive (bfd *abfd, bfd_boolean val)
  abfd->is_thin_archive = val;

static inline void
bfd_set_usrdata (bfd *abfd, void *val)
  abfd->usrdata = val;

static inline asection *
bfd_asymbol_section (const asymbol *sy)
  return sy->section;

static inline bfd_vma
bfd_asymbol_value (const asymbol *sy)
  return sy->section->vma + sy->value;

static inline const char *
bfd_asymbol_name (const asymbol *sy)
  return sy->name;

static inline struct bfd *
bfd_asymbol_bfd (const asymbol *sy)
  return sy->the_bfd;

static inline void
bfd_set_asymbol_name (asymbol *sy, const char *name)
  sy->name = name;

static inline bfd_size_type
bfd_get_section_limit_octets (const bfd *abfd, const asection *sec)
  if (abfd->direction != write_direction && sec->rawsize != 0)
    return sec->rawsize;
  return sec->size;

/* Find the address one past the end of SEC.  */
static inline bfd_size_type
bfd_get_section_limit (const bfd *abfd, const asection *sec)
  return (bfd_get_section_limit_octets (abfd, sec)
          / bfd_octets_per_byte (abfd, sec));

/* Functions to handle insertion and deletion of a bfd's sections.  These
   only handle the list pointers, ie. do not adjust section_count,
   target_index etc.  */
static inline void
bfd_section_list_remove (bfd *abfd, asection *s)
  asection *next = s->next;
  asection *prev = s->prev;
  if (prev)
    prev->next = next;
    abfd->sections = next;
  if (next)
    next->prev = prev;
    abfd->section_last = prev;

static inline void
bfd_section_list_append (bfd *abfd, asection *s)
  s->next = 0;
  if (abfd->section_last)
      s->prev = abfd->section_last;
      abfd->section_last->next = s;
      s->prev = 0;
      abfd->sections = s;
  abfd->section_last = s;

static inline void
bfd_section_list_prepend (bfd *abfd, asection *s)
  s->prev = 0;
  if (abfd->sections)
      s->next = abfd->sections;
      abfd->sections->prev = s;
      s->next = 0;
      abfd->section_last = s;
  abfd->sections = s;

static inline void
bfd_section_list_insert_after (bfd *abfd, asection *a, asection *s)
  asection *next = a->next;
  s->next = next;
  s->prev = a;
  a->next = s;
  if (next)
    next->prev = s;
    abfd->section_last = s;

static inline void
bfd_section_list_insert_before (bfd *abfd, asection *b, asection *s)
  asection *prev = b->prev;
  s->prev = prev;
  s->next = b;
  b->prev = s;
  if (prev)
    prev->next = s;
    abfd->sections = s;

static inline bfd_boolean
bfd_section_removed_from_list (const bfd *abfd, const asection *s)
  return s->next ? s->next->prev != s : abfd->section_last != s;

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