bfdlink.h

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  /* Hash table handled by BFD.  */
  struct bfd_link_hash_table *hash;

  /* Hash table of symbols to keep.  This is NULL unless strip is
     strip_some.  */
  struct bfd_hash_table *keep_hash;

  /* Hash table of symbols to report back via the notice callback.  If
     this is NULL, and notice_all is FALSE, then no symbols are
     reported back.  */
  struct bfd_hash_table *notice_hash;

  /* Hash table of symbols which are being wrapped (the --wrap linker
     option).  If this is NULL, no symbols are being wrapped.  */
  struct bfd_hash_table *wrap_hash;

  /* The list of input BFD's involved in the link.  These are chained
     together via the link_next field.  */
  bfd *input_bfds;

  /* If a symbol should be created for each input BFD, this is section
     where those symbols should be placed.  It must be a section in
     the output BFD.  It may be NULL, in which case no such symbols
     will be created.  This is to support CREATE_OBJECT_SYMBOLS in the
     linker command language.  */
  asection *create_object_symbols_section;

  /* List of global symbol names that are starting points for marking
     sections against garbage collection.  */
  struct bfd_sym_chain *gc_sym_list;

  /* If a base output file is wanted, then this points to it */
  void *base_file;

  /* The function to call when the executable or shared object is
     loaded.  */
  const char *init_function;

  /* The function to call when the executable or shared object is
     unloaded.  */
  const char *fini_function;

  /* Number of relaxation passes.  Usually only one relaxation pass
     is needed.  But a backend can have as many relaxation passes as
     necessary.  During bfd_relax_section call, it is set to the
     current pass, starting from 0.  */
  int relax_pass;

  /* Non-zero if auto-import thunks for DATA items in pei386 DLLs
     should be generated/linked against.  Set to 1 if this feature
     is explicitly requested by the user, -1 if enabled by default.  */
  int pei386_auto_import;

  /* Non-zero if runtime relocs for DATA items with non-zero addends
     in pei386 DLLs should be generated.  Set to 1 if this feature
     is explicitly requested by the user, -1 if enabled by default.  */
  int pei386_runtime_pseudo_reloc;

  /* How many spare .dynamic DT_NULL entries should be added?  */
  unsigned int spare_dynamic_tags;

  /* May be used to set DT_FLAGS for ELF. */
  bfd_vma flags;

  /* May be used to set DT_FLAGS_1 for ELF. */
  bfd_vma flags_1;

  /* Start and end of RELRO region.  */
  bfd_vma relro_start, relro_end;
};

/* This structures holds a set of callback functions.  These are
   called by the BFD linker routines.  Except for einfo, the first
   argument to each callback function is the bfd_link_info structure
   being used and each function returns a boolean value.  If the
   function returns FALSE, then the BFD function which called it should
   return with a failure indication.  */

struct bfd_link_callbacks
{
  /* A function which is called when an object is added from an
     archive.  ABFD is the archive element being added.  NAME is the
     name of the symbol which caused the archive element to be pulled
     in.  */
  bfd_boolean (*add_archive_element)
    (struct bfd_link_info *, bfd *abfd, const char *name);
  /* A function which is called when a symbol is found with multiple
     definitions.  NAME is the symbol which is defined multiple times.
     OBFD is the old BFD, OSEC is the old section, OVAL is the old
     value, NBFD is the new BFD, NSEC is the new section, and NVAL is
     the new value.  OBFD may be NULL.  OSEC and NSEC may be
     bfd_com_section or bfd_ind_section.  */
  bfd_boolean (*multiple_definition)
    (struct bfd_link_info *, const char *name,
     bfd *obfd, asection *osec, bfd_vma oval,
     bfd *nbfd, asection *nsec, bfd_vma nval);
  /* A function which is called when a common symbol is defined
     multiple times.  NAME is the symbol appearing multiple times.
     OBFD is the BFD of the existing symbol; it may be NULL if this is
     not known.  OTYPE is the type of the existing symbol, which may
     be bfd_link_hash_defined, bfd_link_hash_defweak,
     bfd_link_hash_common, or bfd_link_hash_indirect.  If OTYPE is
     bfd_link_hash_common, OSIZE is the size of the existing symbol.
     NBFD is the BFD of the new symbol.  NTYPE is the type of the new
     symbol, one of bfd_link_hash_defined, bfd_link_hash_common, or
     bfd_link_hash_indirect.  If NTYPE is bfd_link_hash_common, NSIZE
     is the size of the new symbol.  */
  bfd_boolean (*multiple_common)
    (struct bfd_link_info *, const char *name,
     bfd *obfd, enum bfd_link_hash_type otype, bfd_vma osize,
     bfd *nbfd, enum bfd_link_hash_type ntype, bfd_vma nsize);
  /* A function which is called to add a symbol to a set.  ENTRY is
     the link hash table entry for the set itself (e.g.,
     __CTOR_LIST__).  RELOC is the relocation to use for an entry in
     the set when generating a relocatable file, and is also used to
     get the size of the entry when generating an executable file.
     ABFD, SEC and VALUE identify the value to add to the set.  */
  bfd_boolean (*add_to_set)
    (struct bfd_link_info *, struct bfd_link_hash_entry *entry,
     bfd_reloc_code_real_type reloc, bfd *abfd, asection *sec, bfd_vma value);
  /* A function which is called when the name of a g++ constructor or
     destructor is found.  This is only called by some object file
     formats.  CONSTRUCTOR is TRUE for a constructor, FALSE for a
     destructor.  This will use BFD_RELOC_CTOR when generating a
     relocatable file.  NAME is the name of the symbol found.  ABFD,
     SECTION and VALUE are the value of the symbol.  */
  bfd_boolean (*constructor)
    (struct bfd_link_info *, bfd_boolean constructor, const char *name,
     bfd *abfd, asection *sec, bfd_vma value);
  /* A function which is called to issue a linker warning.  For
     example, this is called when there is a reference to a warning
     symbol.  WARNING is the warning to be issued.  SYMBOL is the name
     of the symbol which triggered the warning; it may be NULL if
     there is none.  ABFD, SECTION and ADDRESS identify the location
     which trigerred the warning; either ABFD or SECTION or both may
     be NULL if the location is not known.  */
  bfd_boolean (*warning)
    (struct bfd_link_info *, const char *warning, const char *symbol,
     bfd *abfd, asection *section, bfd_vma address);
  /* A function which is called when a relocation is attempted against
     an undefined symbol.  NAME is the symbol which is undefined.
     ABFD, SECTION and ADDRESS identify the location from which the
     reference is made. FATAL indicates whether an undefined symbol is
     a fatal error or not. In some cases SECTION may be NULL.  */
  bfd_boolean (*undefined_symbol)
    (struct bfd_link_info *, const char *name, bfd *abfd,
     asection *section, bfd_vma address, bfd_boolean fatal);
  /* A function which is called when a reloc overflow occurs. ENTRY is
     the link hash table entry for the symbol the reloc is against.
     NAME is the name of the local symbol or section the reloc is
     against, RELOC_NAME is the name of the relocation, and ADDEND is
     any addend that is used.  ABFD, SECTION and ADDRESS identify the
     location at which the overflow occurs; if this is the result of a
     bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
     ABFD will be NULL.  */
  bfd_boolean (*reloc_overflow)
    (struct bfd_link_info *, struct bfd_link_hash_entry *entry,
     const char *name, const char *reloc_name, bfd_vma addend,
     bfd *abfd, asection *section, bfd_vma address);
  /* A function which is called when a dangerous reloc is performed.
     MESSAGE is an appropriate message.
     ABFD, SECTION and ADDRESS identify the location at which the
     problem occurred; if this is the result of a
     bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
     ABFD will be NULL.  */
  bfd_boolean (*reloc_dangerous)
    (struct bfd_link_info *, const char *message,
     bfd *abfd, asection *section, bfd_vma address);
  /* A function which is called when a reloc is found to be attached
     to a symbol which is not being written out.  NAME is the name of
     the symbol.  ABFD, SECTION and ADDRESS identify the location of
     the reloc; if this is the result of a
     bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then
     ABFD will be NULL.  */
  bfd_boolean (*unattached_reloc)
    (struct bfd_link_info *, const char *name,
     bfd *abfd, asection *section, bfd_vma address);
  /* A function which is called when a symbol in notice_hash is
     defined or referenced.  NAME is the symbol.  ABFD, SECTION and
     ADDRESS are the value of the symbol.  If SECTION is
     bfd_und_section, this is a reference.  */
  bfd_boolean (*notice)
    (struct bfd_link_info *, const char *name,
     bfd *abfd, asection *section, bfd_vma address);
  /* General link info message.  */
  void (*einfo)
    (const char *fmt, ...);
};

/* The linker builds link_order structures which tell the code how to
   include input data in the output file.  */

/* These are the types of link_order structures.  */

enum bfd_link_order_type
{
  bfd_undefined_link_order,	/* Undefined.  */
  bfd_indirect_link_order,	/* Built from a section.  */
  bfd_data_link_order,		/* Set to explicit data.  */
  bfd_section_reloc_link_order,	/* Relocate against a section.  */
  bfd_symbol_reloc_link_order	/* Relocate against a symbol.  */
};

/* This is the link_order structure itself.  These form a chain
   attached to the output section whose contents they are describing.  */

struct bfd_link_order
{
  /* Next link_order in chain.  */
  struct bfd_link_order *next;
  /* Type of link_order.  */
  enum bfd_link_order_type type;
  /* Offset within output section.  */
  bfd_vma offset;
  /* Size within output section.  */
  bfd_size_type size;
  /* Type specific information.  */
  union
    {
      struct
	{
	  /* Section to include.  If this is used, then
	     section->output_section must be the section the
	     link_order is attached to, section->output_offset must
	     equal the link_order offset field, and section->size
	     must equal the link_order size field.  Maybe these
	     restrictions should be relaxed someday.  */
	  asection *section;
	} indirect;
      struct
	{
	  /* Size of contents, or zero when contents size == size
	     within output section.
	     A non-zero value allows filling of the output section
	     with an arbitrary repeated pattern.  */
	  unsigned int size;
	  /* Data to put into file.  */
	  bfd_byte *contents;
	} data;
      struct
	{
	  /* Description of reloc to generate.  Used for
	     bfd_section_reloc_link_order and
	     bfd_symbol_reloc_link_order.  */
	  struct bfd_link_order_reloc *p;
	} reloc;
    } u;
};

/* A linker order of type bfd_section_reloc_link_order or
   bfd_symbol_reloc_link_order means to create a reloc against a
   section or symbol, respectively.  This is used to implement -Ur to
   generate relocs for the constructor tables.  The
   bfd_link_order_reloc structure describes the reloc that BFD should
   create.  It is similar to a arelent, but I didn't use arelent
   because the linker does not know anything about most symbols, and
   any asymbol structure it creates will be partially meaningless.
   This information could logically be in the bfd_link_order struct,
   but I didn't want to waste the space since these types of relocs
   are relatively rare.  */

struct bfd_link_order_reloc
{
  /* Reloc type.  */
  bfd_reloc_code_real_type reloc;

  union
    {
      /* For type bfd_section_reloc_link_order, this is the section
	 the reloc should be against.  This must be a section in the
	 output BFD, not any of the input BFDs.  */
      asection *section;
      /* For type bfd_symbol_reloc_link_order, this is the name of the
	 symbol the reloc should be against.  */
      const char *name;
    } u;

  /* Addend to use.  The object file should contain zero.  The BFD
     backend is responsible for filling in the contents of the object
     file correctly.  For some object file formats (e.g., COFF) the
     addend must be stored into in the object file, and for some
     (e.g., SPARC a.out) it is kept in the reloc.  */
  bfd_vma addend;
};

/* Allocate a new link_order for a section.  */
extern struct bfd_link_order *bfd_new_link_order (bfd *, asection *);

/* These structures are used to describe version information for the
   ELF linker.  These structures could be manipulated entirely inside
   BFD, but it would be a pain.  Instead, the regular linker sets up
   these structures, and then passes them into BFD.  */

/* Glob pattern for a version.  */

struct bfd_elf_version_expr
{
  /* Next glob pattern for this version.  */
  struct bfd_elf_version_expr *next;
  /* Glob pattern.  */
  const char *pattern;
  /* NULL for a glob pattern, otherwise a straight symbol.  */
  const char *symbol;
  /* Defined by ".symver".  */
  unsigned int symver : 1;
  /* Defined by version script.  */
  unsigned int script : 1;
  /* Pattern type.  */
#define BFD_ELF_VERSION_C_TYPE		1
#define BFD_ELF_VERSION_CXX_TYPE	2
#define BFD_ELF_VERSION_JAVA_TYPE	4
  unsigned int mask : 3;
};

struct bfd_elf_version_expr_head
{
  /* List of all patterns, both wildcards and non-wildcards.  */
  struct bfd_elf_version_expr *list;
  /* Hash table for non-wildcards.  */
  void *htab;
  /* Remaining patterns.  */
  struct bfd_elf_version_expr *remaining;
  /* What kind of pattern types are present in list (bitmask).  */
  unsigned int mask;
};

/* Version dependencies.  */

struct bfd_elf_version_deps
{
  /* Next dependency for this version.  */
  struct bfd_elf_version_deps *next;
  /* The version which this version depends upon.  */
  struct bfd_elf_version_tree *version_needed;
};

/* A node in the version tree.  */

struct bfd_elf_version_tree
{
  /* Next version.  */
  struct bfd_elf_version_tree *next;
  /* Name of this version.  */
  const char *name;
  /* Version number.  */
  unsigned int vernum;
  /* Regular expressions for global symbols in this version.  */
  struct bfd_elf_version_expr_head globals;
  /* Regular expressions for local symbols in this version.  */
  struct bfd_elf_version_expr_head locals;
  /* List of versions which this version depends upon.  */
  struct bfd_elf_version_deps *deps;
  /* Index of the version name.  This is used within BFD.  */
  unsigned int name_indx;
  /* Whether this version tree was used.  This is used within BFD.  */
  int used;
  /* Matching hook.  */
  struct bfd_elf_version_expr *(*match)
    (struct bfd_elf_version_expr_head *head,
     struct bfd_elf_version_expr *prev, const char *sym);
};

#endif