elf-bfd.h

基于4个mips核的noc设计

  int elf_machine_code;

  /* The maximum page size for this backend.  */
  bfd_vma maxpagesize;

  /* A function to translate an ELF RELA relocation to a BFD arelent
     structure.  */
  void (*elf_info_to_howto) PARAMS ((bfd *, arelent *,
				     Elf_Internal_Rela *));

  /* A function to translate an ELF REL relocation to a BFD arelent
     structure.  */
  void (*elf_info_to_howto_rel) PARAMS ((bfd *, arelent *,
					 Elf_Internal_Rel *));

  /* 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.  */
  boolean (*elf_backend_sym_is_global) PARAMS ((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.  */
  boolean (*elf_backend_object_p) PARAMS ((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) PARAMS ((bfd *, asymbol *));

  /* A function to do additional symbol processing after reading the
     entire ELF symbol table.  */
  boolean (*elf_backend_symbol_table_processing) PARAMS ((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) PARAMS (( Elf_Internal_Sym *, int));

  /* 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.  */
  boolean (*elf_backend_section_processing) PARAMS ((bfd *,
						     Elf32_Internal_Shdr *));

  /* A function to handle unusual section types when creating BFD
     sections from ELF sections.  */
  boolean (*elf_backend_section_from_shdr) PARAMS ((bfd *,
						    Elf32_Internal_Shdr *,
						    char *));

  /* A function to convert machine dependent section header flags to
     BFD internal section header flags.  */
  boolean (*elf_backend_section_flags) PARAMS ((flagword *,
						Elf32_Internal_Shdr *));

  /* A function to handle unusual program segment types when creating BFD
     sections from ELF program segments.  */
  boolean (*elf_backend_section_from_phdr) PARAMS ((bfd *,
						    Elf32_Internal_Phdr *,
						    int));

  /* A function to set up the ELF section header for a BFD section in
     preparation for writing it out.  This is where the flags and type
     fields are set for unusual sections.  */
  boolean (*elf_backend_fake_sections) PARAMS ((bfd *, Elf32_Internal_Shdr *,
						asection *));

  /* A function to get the ELF section index for a BFD section.  If
     this returns true, the section was found.  If it is a normal ELF
     section, *RETVAL should be left unchanged.  If it is not a normal
     ELF section *RETVAL should be set to the SHN_xxxx index.  */
  boolean (*elf_backend_section_from_bfd_section)
    PARAMS ((bfd *, Elf32_Internal_Shdr *, asection *, int *retval));

  /* If this field is not NULL, it is called by the add_symbols phase
     of a link just before adding a symbol to the global linker hash
     table.  It may modify any of the fields as it wishes.  If *NAME
     is set to NULL, the symbol will be skipped rather than being
     added to the hash table.  This function is responsible for
     handling all processor dependent symbol bindings and section
     indices, and must set at least *FLAGS and *SEC for each processor
     dependent case; failure to do so will cause a link error.  */
  boolean (*elf_add_symbol_hook)
    PARAMS ((bfd *abfd, struct bfd_link_info *info,
	     const Elf_Internal_Sym *, const char **name,
	     flagword *flags, asection **sec, bfd_vma *value));

  /* If this field is not NULL, it is called by the elf_link_output_sym
     phase of a link for each symbol which will appear in the object file.  */
  boolean (*elf_backend_link_output_symbol_hook)
    PARAMS ((bfd *, struct bfd_link_info *info, const char *,
	     Elf_Internal_Sym *, asection *));

  /* The CREATE_DYNAMIC_SECTIONS function is called by the ELF backend
     linker the first time it encounters a dynamic object in the link.
     This function must create any sections required for dynamic
     linking.  The ABFD argument is a dynamic object.  The .interp,
     .dynamic, .dynsym, .dynstr, and .hash functions have already been
     created, and this function may modify the section flags if
     desired.  This function will normally create the .got and .plt
     sections, but different backends have different requirements.  */
  boolean (*elf_backend_create_dynamic_sections)
    PARAMS ((bfd *abfd, struct bfd_link_info *info));

  /* The CHECK_RELOCS function is called by the add_symbols phase of
     the ELF backend linker.  It is called once for each section with
     relocs of an object file, just after the symbols for the object
     file have been added to the global linker hash table.  The
     function must look through the relocs and do any special handling
     required.  This generally means allocating space in the global
     offset table, and perhaps allocating space for a reloc.  The
     relocs are always passed as Rela structures; if the section
     actually uses Rel structures, the r_addend field will always be
     zero.  */
  boolean (*check_relocs)
    PARAMS ((bfd *abfd, struct bfd_link_info *info, asection *o,
	     const Elf_Internal_Rela *relocs));

  /* The ADJUST_DYNAMIC_SYMBOL function is called by the ELF backend
     linker for every symbol which is defined by a dynamic object and
     referenced by a regular object.  This is called after all the
     input files have been seen, but before the SIZE_DYNAMIC_SECTIONS
     function has been called.  The hash table entry should be
     bfd_link_hash_defined ore bfd_link_hash_defweak, and it should be
     defined in a section from a dynamic object.  Dynamic object
     sections are not included in the final link, and this function is
     responsible for changing the value to something which the rest of
     the link can deal with.  This will normally involve adding an
     entry to the .plt or .got or some such section, and setting the
     symbol to point to that.  */
  boolean (*elf_backend_adjust_dynamic_symbol)
    PARAMS ((struct bfd_link_info *info, struct elf_link_hash_entry *h));

  /* The ALWAYS_SIZE_SECTIONS function is called by the backend linker
     after all the linker input files have been seen but before the
     section sizes have been set.  This is called after
     ADJUST_DYNAMIC_SYMBOL, but before SIZE_DYNAMIC_SECTIONS.  */
  boolean (*elf_backend_always_size_sections)
    PARAMS ((bfd *output_bfd, struct bfd_link_info *info));

  /* The SIZE_DYNAMIC_SECTIONS function is called by the ELF backend
     linker after all the linker input files have been seen but before
     the sections sizes have been set.  This is called after
     ADJUST_DYNAMIC_SYMBOL has been called on all appropriate symbols.
     It is only called when linking against a dynamic object.  It must
     set the sizes of the dynamic sections, and may fill in their
     contents as well.  The generic ELF linker can handle the .dynsym,
     .dynstr and .hash sections.  This function must handle the
     .interp section and any sections created by the
     CREATE_DYNAMIC_SECTIONS entry point.  */
  boolean (*elf_backend_size_dynamic_sections)
    PARAMS ((bfd *output_bfd, struct bfd_link_info *info));

  /* The RELOCATE_SECTION function is called by the ELF backend linker
     to handle the relocations for a section.

     The relocs are always passed as Rela structures; if the section
     actually uses Rel structures, the r_addend field will always be
     zero.

     This function is responsible for adjust the section contents as
     necessary, and (if using Rela relocs and generating a
     relocateable output file) adjusting the reloc addend as
     necessary.

     This function does not have to worry about setting the reloc
     address or the reloc symbol index.

     LOCAL_SYMS is a pointer to the swapped in local symbols.

     LOCAL_SECTIONS is an array giving the section in the input file
     corresponding to the st_shndx field of each local symbol.

     The global hash table entry for the global symbols can be found
     via elf_sym_hashes (input_bfd).

     When generating relocateable output, this function must handle
     STB_LOCAL/STT_SECTION symbols specially.  The output symbol is
     going to be the section symbol corresponding to the output
     section, which means that the addend must be adjusted
     accordingly.  */
  boolean (*elf_backend_relocate_section)
    PARAMS ((bfd *output_bfd, struct bfd_link_info *info,
	     bfd *input_bfd, asection *input_section, bfd_byte *contents,
	     Elf_Internal_Rela *relocs, Elf_Internal_Sym *local_syms,
	     asection **local_sections));

  /* The FINISH_DYNAMIC_SYMBOL function is called by the ELF backend
     linker just before it writes a symbol out to the .dynsym section.
     The processor backend may make any required adjustment to the
     symbol.  It may also take the opportunity to set contents of the
     dynamic sections.  Note that FINISH_DYNAMIC_SYMBOL is called on
     all .dynsym symbols, while ADJUST_DYNAMIC_SYMBOL is only called
     on those symbols which are defined by a dynamic object.  */
  boolean (*elf_backend_finish_dynamic_symbol)
    PARAMS ((bfd *output_bfd, struct bfd_link_info *info,
	     struct elf_link_hash_entry *h, Elf_Internal_Sym *sym));

  /* The FINISH_DYNAMIC_SECTIONS function is called by the ELF backend
     linker just before it writes all the dynamic sections out to the
     output file.  The FINISH_DYNAMIC_SYMBOL will have been called on
     all dynamic symbols.  */
  boolean (*elf_backend_finish_dynamic_sections)
    PARAMS ((bfd *output_bfd, struct bfd_link_info *info));

  /* A function to do any beginning processing needed for the ELF file
     before building the ELF headers and computing file positions.  */
  void (*elf_backend_begin_write_processing)
    PARAMS ((bfd *, struct bfd_link_info *));

  /* A function to do any final processing needed for the ELF file
     before writing it out.  The LINKER argument is true if this BFD
     was created by the ELF backend linker.  */
  void (*elf_backend_final_write_processing)
    PARAMS ((bfd *, boolean linker));

  /* This function is called by get_program_header_size.  It should
     return the number of additional program segments which this BFD
     will need.  It should return -1 on error.  */
  int (*elf_backend_additional_program_headers) PARAMS ((bfd *));

  /* This function is called to modify an existing segment map in a
     backend specific fashion.  */
  boolean (*elf_backend_modify_segment_map) PARAMS ((bfd *));

  /* This function is called during section gc to discover the section a
     particular relocation refers to.  It need not be defined for hosts
     that have no queer relocation types.  */
  asection * (*gc_mark_hook)
    PARAMS ((bfd *abfd, struct bfd_link_info *, Elf_Internal_Rela *,
	     struct elf_link_hash_entry *h, Elf_Internal_Sym *));

  /* This function, if defined, is called during the sweep phase of gc
     in order that a backend might update any data structures it might
     be maintaining.  */
  boolean (*gc_sweep_hook)
    PARAMS ((bfd *abfd, struct bfd_link_info *info, asection *o,
	     const Elf_Internal_Rela *relocs));

  /* This function, if defined, is called after the ELF headers have
     been created.  This allows for things like the OS and ABI versions
     to be changed.  */
  void (*elf_backend_post_process_headers)
    PARAMS ((bfd *, struct bfd_link_info *));

  /* This function, if defined, prints a symbol to file and returns the
     name of the symbol to be printed.  It should return NULL to fall
     back to default symbol printing.  */
  const char *(*elf_backend_print_symbol_all)
    PARAMS ((bfd *, PTR, asymbol *));

  /* This function, if defined, is called after all local symbols and
     global symbols converted to locals are emited into the symtab
     section.  It allows the backend to emit special global symbols
     not handled in the hash table.  */
  boolean (*elf_backend_output_arch_syms)
    PARAMS ((bfd *, struct bfd_link_info *, PTR,
	    boolean (*) PARAMS ((PTR, const char *,
             Elf_Internal_Sym *, asection *))));

  /* Copy any information related to dynamic linking from a pre-existing
     symbol IND to a newly created symbol DIR.  */
  void (*elf_backend_copy_indirect_symbol)
    PARAMS ((struct elf_link_hash_entry *, struct elf_link_hash_entry *));

  /* Modify any information related to dynamic linking such that the
     symbol is not exported.  */
  void (*elf_backend_hide_symbol)
    PARAMS ((struct bfd_link_info *, struct elf_link_hash_entry *));

  /* The swapping table to use when dealing with ECOFF information.
     Used for the MIPS ELF .mdebug section.  */
  const struct ecoff_debug_swap *elf_backend_ecoff_debug_swap;

  /* Alternate EM_xxxx machine codes for this backend.  */
  int elf_machine_alt1;
  int elf_machine_alt2;

  const struct elf_size_info *s;

  /* offset of the _GLOBAL_OFFSET_TABLE_ symbol from the start of the
     .got section */
  bfd_vma got_symbol_offset;

  /* The size in bytes of the headers for the GOT and PLT.  This includes
     the so-called reserved entries on some systems.  */
  bfd_vma got_header_size;
  bfd_vma plt_header_size;

  /* This is true if the linker should act like collect and gather
     global constructors and destructors by name.  This is true for
     MIPS ELF because the Irix 5 tools can not handle the .init
     section.  */
  unsigned collect : 1;

  /* This is true if the linker should ignore changes to the type of a
     symbol.  This is true for MIPS ELF because some Irix 5 objects
     record undefined functions as STT_OBJECT although the definitions
     are STT_FUNC.  */
  unsigned type_change_ok : 1;

  /* Whether the backend may use REL relocations.  (Some backends use
     both REL and RELA relocations, and this flag is set for those
     backends.)  */
  unsigned may_use_rel_p : 1;

  /* Whether the backend may use RELA relocations.  (Some backends use
     both REL and RELA relocations, and this flag is set for those
     backends.)  */
  unsigned may_use_rela_p : 1;

  /* Whether the default relocation type is RELA.  If a backend with
     this flag set wants REL relocations for a particular section,
     it must note that explicitly.  Similarly, if this flag is clear,
     and the backend wants RELA relocations for a particular
     section.  */
  unsigned default_use_rela_p : 1;

  /* True if addresses "naturally" sign extend.  This is used when
     swapping in from Elf32 when BFD64.  */
  unsigned sign_extend_vma : 1;

  unsigned want_got_plt : 1;
  unsigned plt_readonly : 1;
  unsigned want_plt_sym : 1;
  unsigned plt_not_loaded : 1;