/* bfdlink.h -- header file for BFD link routines

   Copyright (C) 1993-2018 Free Software Foundation, Inc.

   Written by Steve Chamberlain and Ian Lance Taylor, 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 BFDLINK_H

#define BFDLINK_H

/* Which symbols to strip during a link.  */

enum bfd_link_strip

{

  strip_none,		/* Don't strip any symbols.  */

  strip_debugger,	/* Strip debugging symbols.  */

  strip_some,		/* keep_hash is the list of symbols to keep.  */

  strip_all		/* Strip all symbols.  */

};

/* Which local symbols to discard during a link.  This is irrelevant

   if strip_all is used.  */

enum bfd_link_discard

{

  discard_sec_merge,	/* Discard local temporary symbols in SEC_MERGE

			   sections.  */

  discard_none,		/* Don't discard any locals.  */

  discard_l,		/* Discard local temporary symbols.  */

  discard_all		/* Discard all locals.  */

};

/* Whether to generate ELF common symbols with the STT_COMMON type

   during a relocatable link.  */

enum bfd_link_elf_stt_common

{

  unchanged,

  elf_stt_common,

  no_elf_stt_common

};

/* Describes the type of hash table entry structure being used.

   Different hash table structure have different fields and so

   support different linking features.  */

enum bfd_link_hash_table_type

  {

    bfd_link_generic_hash_table,

    bfd_link_elf_hash_table

  };

/* These are the possible types of an entry in the BFD link hash

   table.  */

enum bfd_link_hash_type

{

  bfd_link_hash_new,		/* Symbol is new.  */

  bfd_link_hash_undefined,	/* Symbol seen before, but undefined.  */

  bfd_link_hash_undefweak,	/* Symbol is weak and undefined.  */

  bfd_link_hash_defined,	/* Symbol is defined.  */

  bfd_link_hash_defweak,	/* Symbol is weak and defined.  */

  bfd_link_hash_common,		/* Symbol is common.  */

  bfd_link_hash_indirect,	/* Symbol is an indirect link.  */

  bfd_link_hash_warning		/* Like indirect, but warn if referenced.  */

};

enum bfd_link_common_skip_ar_symbols

{

  bfd_link_common_skip_none,

  bfd_link_common_skip_text,

  bfd_link_common_skip_data,

  bfd_link_common_skip_all

};

struct bfd_link_hash_common_entry

  {

    unsigned int alignment_power;	/* Alignment.  */

    asection *section;		/* Symbol section.  */

  };

/* The linking routines use a hash table which uses this structure for

   its elements.  */

struct bfd_link_hash_entry

{

  /* Base hash table entry structure.  */

  struct bfd_hash_entry root;

  /* Type of this entry.  */

  ENUM_BITFIELD (bfd_link_hash_type) type : 8;

  /* Symbol is referenced in a normal regular object file,

     as distinct from a LTO IR object file.  */

  unsigned int non_ir_ref_regular : 1;

  /* Symbol is referenced in a normal dynamic object file,

     as distinct from a LTO IR object file.  */

  unsigned int non_ir_ref_dynamic : 1;

  /* Symbol is a built-in define.  These will be overridden by PROVIDE

     in a linker script.  */

  unsigned int linker_def : 1;

  /* Symbol defined in a linker script.  */

  unsigned int ldscript_def : 1;

  /* A union of information depending upon the type.  */

  union

    {

      /* Nothing is kept for bfd_hash_new.  */

      /* bfd_link_hash_undefined, bfd_link_hash_undefweak.  */

      struct

	{

	  /* Undefined and common symbols are kept in a linked list through

	     this field.  This field is present in all of the union element

	     so that we don't need to remove entries from the list when we

	     change their type.  Removing entries would either require the

	     list to be doubly linked, which would waste more memory, or

	     require a traversal.  When an undefined or common symbol is

	     created, it should be added to this list, the head of which is in

	     the link hash table itself.  As symbols are defined, they need

	     not be removed from the list; anything which reads the list must

	     doublecheck the symbol type.

	     Weak symbols are not kept on this list.

	     Defined and defweak symbols use this field as a reference marker.

	     If the field is not NULL, or this structure is the tail of the

	     undefined symbol list, the symbol has been referenced.  If the

	     symbol is undefined and becomes defined, this field will

	     automatically be non-NULL since the symbol will have been on the

	     undefined symbol list.  */

	  struct bfd_link_hash_entry *next;

	  /* BFD symbol was found in.  */

	  bfd *abfd;

	} undef;

      /* bfd_link_hash_defined, bfd_link_hash_defweak.  */

      struct

	{

	  struct bfd_link_hash_entry *next;

	  /* Symbol section.  */

	  asection *section;

	  /* Symbol value.  */

	  bfd_vma value;

	} def;

      /* bfd_link_hash_indirect, bfd_link_hash_warning.  */

      struct

	{

	  struct bfd_link_hash_entry *next;

	  /* Real symbol.  */

	  struct bfd_link_hash_entry *link;

	  /* Warning message (bfd_link_hash_warning only).  */

	  const char *warning;

	} i;

      /* bfd_link_hash_common.  */

      struct

	{

	  struct bfd_link_hash_entry *next;

	  /* The linker needs to know three things about common

	     symbols: the size, the alignment, and the section in

	     which the symbol should be placed.  We store the size

	     here, and we allocate a small structure to hold the

	     section and the alignment.  The alignment is stored as a

	     power of two.  We don't store all the information

	     directly because we don't want to increase the size of

	     the union; this structure is a major space user in the

	     linker.  */

	  struct bfd_link_hash_common_entry *p;

	  /* Common symbol size.  */

	  bfd_size_type size;

	} c;

    } u;

};

/* This is the link hash table.  It is a derived class of

   bfd_hash_table.  */

struct bfd_link_hash_table

{

  /* The hash table itself.  */

  struct bfd_hash_table table;

  /* A linked list of undefined and common symbols, linked through the

     next field in the bfd_link_hash_entry structure.  */

  struct bfd_link_hash_entry *undefs;

  /* Entries are added to the tail of the undefs list.  */

  struct bfd_link_hash_entry *undefs_tail;

  /* Function to free the hash table on closing BFD.  */

  void (*hash_table_free) (bfd *);

  /* The type of the link hash table.  */

  enum bfd_link_hash_table_type type;

};

/* Look up an entry in a link hash table.  If FOLLOW is TRUE, this

   follows bfd_link_hash_indirect and bfd_link_hash_warning links to

   the real symbol.  */

extern struct bfd_link_hash_entry *bfd_link_hash_lookup

  (struct bfd_link_hash_table *, const char *, bfd_boolean create,

   bfd_boolean copy, bfd_boolean follow);

/* Look up an entry in the main linker hash table if the symbol might

   be wrapped.  This should only be used for references to an

   undefined symbol, not for definitions of a symbol.  */

extern struct bfd_link_hash_entry *bfd_wrapped_link_hash_lookup

  (bfd *, struct bfd_link_info *, const char *, bfd_boolean,

   bfd_boolean, bfd_boolean);

/* If H is a wrapped symbol, ie. the symbol name starts with "__wrap_"

   and the remainder is found in wrap_hash, return the real symbol.  */

extern struct bfd_link_hash_entry *unwrap_hash_lookup

  (struct bfd_link_info *, bfd *, struct bfd_link_hash_entry *);

/* Traverse a link hash table.  */

extern void bfd_link_hash_traverse

  (struct bfd_link_hash_table *,

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

    void *);

/* Add an entry to the undefs list.  */

extern void bfd_link_add_undef

  (struct bfd_link_hash_table *, struct bfd_link_hash_entry *);

/* Remove symbols from the undefs list that don't belong there.  */

extern void bfd_link_repair_undef_list

  (struct bfd_link_hash_table *table);

/* Read symbols and cache symbol pointer array in outsymbols.  */

extern bfd_boolean bfd_generic_link_read_symbols (bfd *);

/* Check the relocs in the BFD.  Called after all the input

   files have been loaded, and garbage collection has tagged

   any unneeded sections.  */

extern bfd_boolean bfd_link_check_relocs (bfd *,struct bfd_link_info *);

struct bfd_sym_chain

{

  struct bfd_sym_chain *next;

  const char *name;

};

/* How to handle unresolved symbols.

   There are four possibilities which are enumerated below:  */

enum report_method

{

  /* This is the initial value when then link_info structure is created.

     It allows the various stages of the linker to determine whether they

     allowed to set the value.  */

  RM_NOT_YET_SET = 0,

  RM_IGNORE,

  RM_GENERATE_WARNING,

  RM_GENERATE_ERROR

};

typedef enum {with_flags, without_flags} flag_type;

/* A section flag list.  */

struct flag_info_list

{

  flag_type with;

  const char *name;

  bfd_boolean valid;

  struct flag_info_list *next;

};

/* Section flag info.  */

struct flag_info

{

  flagword only_with_flags;

  flagword not_with_flags;

  struct flag_info_list *flag_list;

  bfd_boolean flags_initialized;

};

struct bfd_elf_dynamic_list;

struct bfd_elf_version_tree;

/* Types of output.  */

enum output_type

{

  type_pde,

  type_pie,

  type_relocatable,

  type_dll,

};

#define bfd_link_pde(info)	   ((info)->type == type_pde)

#define bfd_link_dll(info)	   ((info)->type == type_dll)

#define bfd_link_relocatable(info) ((info)->type == type_relocatable)

#define bfd_link_pie(info)	   ((info)->type == type_pie)

#define bfd_link_executable(info)  (bfd_link_pde (info) || bfd_link_pie (info))

#define bfd_link_pic(info)	   (bfd_link_dll (info) || bfd_link_pie (info))

/* This structure holds all the information needed to communicate

   between BFD and the linker when doing a link.  */

struct bfd_link_info

{

  /* Output type.  */

  ENUM_BITFIELD (output_type) type : 2;

  /* TRUE if BFD should pre-bind symbols in a shared object.  */

  unsigned int symbolic: 1;

  /* TRUE if executable should not contain copy relocs.

     Setting this true may result in a non-sharable text segment.  */

  unsigned int nocopyreloc: 1;

  /* TRUE if BFD should export all symbols in the dynamic symbol table

     of an executable, rather than only those used.  */

  unsigned int export_dynamic: 1;

  /* TRUE if a default symbol version should be created and used for

     exported symbols.  */

  unsigned int create_default_symver: 1;

  /* TRUE if unreferenced sections should be removed.  */

  unsigned int gc_sections: 1;

  /* TRUE if exported symbols should be kept during section gc.  */

  unsigned int gc_keep_exported: 1;

  /* TRUE if every symbol should be reported back via the notice

     callback.  */

  unsigned int notice_all: 1;

  /* TRUE if the LTO plugin is active.  */

  unsigned int lto_plugin_active: 1;

  /* TRUE if all LTO IR symbols have been read.  */

  unsigned int lto_all_symbols_read : 1;

  /* TRUE if global symbols in discarded sections should be stripped.  */

  unsigned int strip_discarded: 1;

  /* TRUE if all data symbols should be dynamic.  */

  unsigned int dynamic_data: 1;

  /* TRUE if section groups should be resolved.  */

  unsigned int resolve_section_groups: 1;

  /* Which symbols to strip.  */

  ENUM_BITFIELD (bfd_link_strip) strip : 2;

  /* Which local symbols to discard.  */

  ENUM_BITFIELD (bfd_link_discard) discard : 2;

  /* Whether to generate ELF common symbols with the STT_COMMON type.  */

  ENUM_BITFIELD (bfd_link_elf_stt_common) elf_stt_common : 2;

  /* Criteria for skipping symbols when determining

     whether to include an object from an archive. */

  ENUM_BITFIELD (bfd_link_common_skip_ar_symbols) common_skip_ar_symbols : 2;

  /* What to do with unresolved symbols in an object file.

     When producing executables the default is GENERATE_ERROR.

     When producing shared libraries the default is IGNORE.  The

     assumption with shared libraries is that the reference will be

     resolved at load/execution time.  */

  ENUM_BITFIELD (report_method) unresolved_syms_in_objects : 2;

  /* What to do with unresolved symbols in a shared library.

     The same defaults apply.  */

  ENUM_BITFIELD (report_method) unresolved_syms_in_shared_libs : 2;

  /* TRUE if shared objects should be linked directly, not shared.  */

  unsigned int static_link: 1;

  /* TRUE if symbols should be retained in memory, FALSE if they

     should be freed and reread.  */

  unsigned int keep_memory: 1;

  /* TRUE if BFD should generate relocation information in the final

     executable.  */

  unsigned int emitrelocations: 1;

  /* TRUE if PT_GNU_RELRO segment should be created.  */

  unsigned int relro: 1;

  /* TRUE if separate code segment should be created.  */

  unsigned int separate_code: 1;

  /* Nonzero if .eh_frame_hdr section and PT_GNU_EH_FRAME ELF segment

     should be created.  1 for DWARF2 tables, 2 for compact tables.  */

  unsigned int eh_frame_hdr_type: 2;

  /* TRUE if we should warn when adding a DT_TEXTREL to a shared object.  */

  unsigned int warn_shared_textrel: 1;

  /* TRUE if we should error when adding a DT_TEXTREL.  */

  unsigned int error_textrel: 1;

  /* TRUE if .hash section should be created.  */

  unsigned int emit_hash: 1;

  /* TRUE if .gnu.hash section should be created.  */

  unsigned int emit_gnu_hash: 1;

  /* If TRUE reduce memory overheads, at the expense of speed. This will

     cause map file generation to use an O(N^2) algorithm and disable

     caching ELF symbol buffer.  */

  unsigned int reduce_memory_overheads: 1;

  /* TRUE if the output file should be in a traditional format.  This

     is equivalent to the setting of the BFD_TRADITIONAL_FORMAT flag

     on the output file, but may be checked when reading the input

     files.  */

  unsigned int traditional_format: 1;

  /* TRUE if non-PLT relocs should be merged into one reloc section

     and sorted so that relocs against the same symbol come together.  */

  unsigned int combreloc: 1;

  /* TRUE if a default symbol version should be created and used for

     imported symbols.  */

  unsigned int default_imported_symver: 1;

  /* TRUE if the new ELF dynamic tags are enabled. */

  unsigned int new_dtags: 1;

  /* FALSE if .eh_frame unwind info should be generated for PLT and other

     linker created sections, TRUE if it should be omitted.  */

  unsigned int no_ld_generated_unwind_info: 1;

  /* TRUE if BFD should generate a "task linked" object file,

     similar to relocatable but also with globals converted to

     statics.  */

  unsigned int task_link: 1;

  /* TRUE if ok to have multiple definition.  */

  unsigned int allow_multiple_definition: 1;

  /* TRUE if .gnu_object_only section should be created.  */

  unsigned int emit_gnu_object_only: 1;

  /* TRUE if .gnu_object_only section is being created.  */

  unsigned int emitting_gnu_object_only: 1;

  /* TRUE if ok to have version with no definition.  */

  unsigned int allow_undefined_version: 1;

  /* TRUE if some symbols have to be dynamic, controlled by

     --dynamic-list command line options.  */

  unsigned int dynamic: 1;

  /* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W|PF_X

     flags.  */

  unsigned int execstack: 1;

  /* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W

     flags.  */

  unsigned int noexecstack: 1;

  /* TRUE if we want to produced optimized output files.  This might

     need much more time and therefore must be explicitly selected.  */

  unsigned int optimize: 1;

  /* TRUE if user should be informed of removed unreferenced sections.  */

  unsigned int print_gc_sections: 1;

  /* TRUE if we should warn alternate ELF machine code.  */

  unsigned int warn_alternate_em: 1;

  /* TRUE if the linker script contained an explicit PHDRS command.  */

  unsigned int user_phdrs: 1;

  /* TRUE if we should check relocations after all input files have

     been opened.  */

  unsigned int check_relocs_after_open_input: 1;

  /* TRUE if BND prefix in PLT entries is always generated.  */

  unsigned int bndplt: 1;

  /* TRUE if IBT-enabled PLT entries should be generated.  */

  unsigned int ibtplt: 1;

  /* TRUE if GNU_PROPERTY_X86_FEATURE_1_IBT should be generated.  */

  unsigned int ibt: 1;

  /* TRUE if GNU_PROPERTY_X86_FEATURE_1_SHSTK should be generated.  */

  unsigned int shstk: 1;

  /* 0 = > no report, 1 => warn, 2=> error.  */

  unsigned int cet_report: 2;

  /* TRUE if generation of .interp/PT_INTERP should be suppressed.  */

  unsigned int nointerp: 1;

  /* TRUE if we shouldn't check relocation overflow.  */

  unsigned int no_reloc_overflow_check: 1;

  /* TRUE if generate a 1-byte NOP as suffix for x86 call instruction.  */

  unsigned int call_nop_as_suffix : 1;

  /* TRUE if common symbols should be treated as undefined.  */

  unsigned int inhibit_common_definition : 1;

  /* The 1-byte NOP for x86 call instruction.  */

  char call_nop_byte;

  /* Char that may appear as the first char of a symbol, but should be

     skipped (like symbol_leading_char) when looking up symbols in

     wrap_hash.  Used by PowerPC Linux for 'dot' symbols.  */

  char wrap_char;

  /* Separator between archive and filename in linker script filespecs.  */

  char path_separator;

  /* Compress DWARF debug sections.  */

  enum compressed_debug_section_type compress_debug;

  /* Default stack size.  Zero means default (often zero itself), -1

     means explicitly zero-sized.  */

  bfd_signed_vma stacksize;

  /* Enable or disable target specific optimizations.

     Not all targets have optimizations to enable.

     Normally these optimizations are disabled by default but some targets

     prefer to enable them by default.  So this field is a tri-state variable.

     The values are:

     zero: Enable the optimizations (either from --relax being specified on

       the command line or the backend's before_allocation emulation function.

     positive: The user has requested that these optimizations be disabled.

       (Via the --no-relax command line option).

     negative: The optimizations are disabled.  (Set when initializing the

       args_type structure in ldmain.c:main.  */

  signed int disable_target_specific_optimizations;

  /* Function callbacks.  */

  const struct bfd_link_callbacks *callbacks;

  /* 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;

  /* Hash table of symbols which may be left unresolved during

     a link.  If this is NULL, no symbols can be left unresolved.  */

  struct bfd_hash_table *ignore_hash;

  /* The output BFD.  */

  bfd *output_bfd;

  /* The import library generated.  */

  bfd *out_implib_bfd;

  /* The list of input BFD's involved in the link.  These are chained

     together via the link.next field.  */

  bfd *input_bfds;

  bfd **input_bfds_tail;

  /* 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;

  /* Number of relaxation trips.  This number is incremented every

     time the relaxation pass is restarted due to a previous

     relaxation returning true in *AGAIN.  */

  int relax_trip;

  /* > 0 to treat protected data defined in the shared library as

     reference external.  0 to treat it as internal.  -1 to let

     backend to decide.  */

  int extern_protected_data;

  /* 1 to make undefined weak symbols dynamic when building a dynamic

     object.  0 to resolve undefined weak symbols to zero.  -1 to let

     the backend decide.  */

  int dynamic_undefined_weak;

  /* 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;

  /* List of symbols should be dynamic.  */

  struct bfd_elf_dynamic_list *dynamic_list;

  /* The version information.  */

  struct bfd_elf_version_tree *version_info;

};

/* This structures holds a set of callback functions.  These are called

   by the BFD linker routines.  */

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.  This function may set *SUBSBFD to point to an alternative

     BFD from which symbols should in fact be added in place of the

     original BFD's symbols.  Returns TRUE if the object should be

     added, FALSE if it should be skipped.  */

  bfd_boolean (*add_archive_element)

    (struct bfd_link_info *, bfd *abfd, const char *name, bfd **subsbfd);

  /* A function which is called when a symbol is found with multiple

     definitions.  H is the symbol which is defined multiple times.

     NBFD is the new BFD, NSEC is the new section, and NVAL is the new

     value.  NSEC may be bfd_com_section or bfd_ind_section.  */

  void (*multiple_definition)

    (struct bfd_link_info *, struct bfd_link_hash_entry *h,

     bfd *nbfd, asection *nsec, bfd_vma nval);

  /* A function which is called when a common symbol is defined

     multiple times.  H is the symbol appearing multiple times.

     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.  */

  void (*multiple_common)

    (struct bfd_link_info *, struct bfd_link_hash_entry *h,

     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.  */

  void (*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.  */

  void (*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.  */

  void (*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. IS_FATAL indicates whether an undefined symbol is

     a fatal error or not. In some cases SECTION may be NULL.  */

  void (*undefined_symbol)

    (struct bfd_link_info *, const char *name, bfd *abfd,

     asection *section, bfd_vma address, bfd_boolean is_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.  */

  void (*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.  */

  void (*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.  */

  void (*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.  H is the symbol, INH the indirect symbol

     if applicable.  ABFD, SECTION and ADDRESS are the (new) value of

     the symbol.  If SECTION is bfd_und_section, this is a reference.

     FLAGS are the symbol BSF_* flags.  */

  bfd_boolean (*notice)

    (struct bfd_link_info *, struct bfd_link_hash_entry *h,

     struct bfd_link_hash_entry *inh,

     bfd *abfd, asection *section, bfd_vma address, flagword flags);

  /* Error or warning link info message.  */

  void (*einfo)

    (const char *fmt, ...);

  /* General link info message.  */

  void (*info)

    (const char *fmt, ...);

  /* Message to be printed in linker map file.  */

  void (*minfo)

    (const char *fmt, ...);

  /* This callback provides a chance for users of the BFD library to

     override its decision about whether to place two adjacent sections

     into the same segment.  */

  bfd_boolean (*override_segment_assignment)

    (struct bfd_link_info *, bfd * abfd,

     asection * current_section, asection * previous_section,

     bfd_boolean new_segment);

};

/* 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 should be filled by

	     the architecture-dependent fill function.

	     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.  */