bfd/elfxx-x86.h

/* x86 specific support for ELF
   Copyright (C) 2017-2021 Free Software Foundation, Inc.

   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.  */

/* Don't generate unused section symbols.  */
#define TARGET_KEEP_UNUSED_SECTION_SYMBOLS false

#include "sysdep.h"
#include "bfd.h"
#include "bfdlink.h"
#include "libbfd.h"
#include "elf-bfd.h"
#include "hashtab.h"
#include "elf-linker-x86.h"

#define PLT_CIE_LENGTH		20
#define PLT_FDE_LENGTH		36
#define PLT_FDE_START_OFFSET	4 + PLT_CIE_LENGTH + 8
#define PLT_FDE_LEN_OFFSET	4 + PLT_CIE_LENGTH + 12

#define ABI_64_P(abfd) \
  (get_elf_backend_data (abfd)->s->elfclass == ELFCLASS64)

/* If ELIMINATE_COPY_RELOCS is non-zero, the linker will try to avoid
   copying dynamic variables from a shared lib into an app's dynbss
   section, and instead use a dynamic relocation to point into the
   shared lib.  */
#define ELIMINATE_COPY_RELOCS 1

#define elf_x86_hash_table(p, id) \
  (is_elf_hash_table ((p)->hash) \
   && elf_hash_table_id ((struct elf_link_hash_table *) ((p)->hash)) == (id) \
    ? ((struct elf_x86_link_hash_table *) ((p)->hash)) : NULL)

/* Will references to this symbol always be local in this object?  */
#define SYMBOL_REFERENCES_LOCAL_P(INFO, H) \
  _bfd_x86_elf_link_symbol_references_local ((INFO), (H))

/* TRUE if an undefined weak symbol should be resolved to 0.  Local
   undefined weak symbol is always resolved to 0.  Reference to an
   undefined weak symbol is resolved to 0 in executable if undefined
   weak symbol should be resolved to 0 (zero_undefweak > 0).  */
#define UNDEFINED_WEAK_RESOLVED_TO_ZERO(INFO, EH) \
  ((EH)->elf.root.type == bfd_link_hash_undefweak		 \
   && (SYMBOL_REFERENCES_LOCAL_P ((INFO), &(EH)->elf)		 \
       || (bfd_link_executable (INFO)				 \
	   && (EH)->zero_undefweak > 0)))

/* Should copy relocation be generated for a symbol.  Don't generate
   copy relocation against a protected symbol defined in a shared
   object with GNU_PROPERTY_NO_COPY_ON_PROTECTED.  */
#define SYMBOL_NO_COPYRELOC(INFO, EH) \
  ((EH)->def_protected \
   && ((EH)->elf.root.type == bfd_link_hash_defined \
       || (EH)->elf.root.type == bfd_link_hash_defweak) \
   && elf_has_no_copy_on_protected ((EH)->elf.root.u.def.section->owner) \
   && ((EH)->elf.root.u.def.section->owner->flags & DYNAMIC) != 0 \
   && ((EH)->elf.root.u.def.section->flags & SEC_CODE) == 0)

/* TRUE if dynamic relocation is needed.  If we are creating a shared
   library, and this is a reloc against a global symbol, or a non PC
   relative reloc against a local symbol, then we need to copy the reloc
   into the shared library.  However, if we are linking with -Bsymbolic,
   we do not need to copy a reloc against a global symbol which is
   defined in an object we are including in the link (i.e., DEF_REGULAR
   is set).

   If PCREL_PLT is true, don't generate dynamic relocation in PIE for
   PC-relative relocation against a dynamic function definition in data
   section when PLT address can be used.

   If on the other hand, we are creating an executable, we may need to
   keep relocations for symbols satisfied by a dynamic library if we
   manage to avoid copy relocs for the symbol.

   We also need to generate dynamic pointer relocation against
   STT_GNU_IFUNC symbol in the non-code section.  */
#define NEED_DYNAMIC_RELOCATION_P(INFO, PCREL_PLT, H, SEC, R_TYPE, \
				  POINTER_TYPE) \
  ((bfd_link_pic (INFO) \
    && (! X86_PCREL_TYPE_P (R_TYPE) \
	|| ((H) != NULL \
	    && (! (bfd_link_pie (INFO) \
		   || SYMBOLIC_BIND ((INFO), (H))) \
		|| (H)->root.type == bfd_link_hash_defweak \
		|| (!(bfd_link_pie (INFO) \
		      && (PCREL_PLT) \
		      && (H)->plt.refcount > 0 \
		      && ((SEC)->flags & SEC_CODE) == 0 \
		      && (H)->type == STT_FUNC \
		      && (H)->def_dynamic) \
		    && !(H)->def_regular))))) \
   || ((H) != NULL \
       && (H)->type == STT_GNU_IFUNC \
       && (R_TYPE) == POINTER_TYPE \
       && ((SEC)->flags & SEC_CODE) == 0) \
   || (ELIMINATE_COPY_RELOCS \
       && !bfd_link_pic (INFO) \
       && (H) != NULL \
       && ((H)->root.type == bfd_link_hash_defweak \
	   || !(H)->def_regular)))

/* TRUE if dynamic relocation should be generated.  Don't copy a
   pc-relative relocation into the output file if the symbol needs
   copy reloc or the symbol is undefined when building executable.
   Copy dynamic function pointer relocations.  Don't generate dynamic
   relocations against resolved undefined weak symbols in PIE, except
   when PC32_RELOC is TRUE.  Undefined weak symbol is bound locally
   when PIC is false.  Don't generate dynamic relocations against
   non-preemptible absolute symbol.  */
#define GENERATE_DYNAMIC_RELOCATION_P(INFO, EH, R_TYPE, SEC, \
				      NEED_COPY_RELOC_IN_PIE, \
				      RESOLVED_TO_ZERO, PC32_RELOC) \
  ((bfd_link_pic (INFO) \
    && !(bfd_is_abs_section (SEC) \
	 && ((EH) == NULL \
	     || SYMBOL_REFERENCES_LOCAL (INFO, &(EH)->elf))) \
    && !(NEED_COPY_RELOC_IN_PIE) \
    && ((EH) == NULL \
	|| ((ELF_ST_VISIBILITY ((EH)->elf.other) == STV_DEFAULT \
	     && (!(RESOLVED_TO_ZERO) || PC32_RELOC)) \
	    || (EH)->elf.root.type != bfd_link_hash_undefweak)) \
    && ((!X86_PCREL_TYPE_P (R_TYPE) && !X86_SIZE_TYPE_P (R_TYPE)) \
	|| ! SYMBOL_CALLS_LOCAL ((INFO), \
				 (struct elf_link_hash_entry *) (EH)))) \
   || (ELIMINATE_COPY_RELOCS \
       && !bfd_link_pic (INFO) \
       && (EH) != NULL \
       && (EH)->elf.dynindx != -1 \
       && (!(EH)->elf.non_got_ref \
	   || ((EH)->elf.root.type == bfd_link_hash_undefweak \
	       && !(RESOLVED_TO_ZERO))) \
	       && (((EH)->elf.def_dynamic && !(EH)->elf.def_regular) \
		   || (EH)->elf.root.type == bfd_link_hash_undefined)))

/* TRUE if this input relocation should be copied to output.  H->dynindx
   may be -1 if this symbol was marked to become local.  */
#define COPY_INPUT_RELOC_P(INFO, H, R_TYPE) \
  ((H) != NULL \
   && (H)->dynindx != -1 \
   && (X86_PCREL_TYPE_P (R_TYPE) \
       || !(bfd_link_executable (INFO) || SYMBOLIC_BIND ((INFO), (H))) \
       || !(H)->def_regular))

/* TRUE if this is actually a static link, or it is a -Bsymbolic link
   and the symbol is defined locally, or the symbol was forced to be
   local because of a version file.  */
#define RESOLVED_LOCALLY_P(INFO, H, HTAB) \
  (!WILL_CALL_FINISH_DYNAMIC_SYMBOL ((HTAB)->elf.dynamic_sections_created, \
				     bfd_link_pic (INFO), (H)) \
   || (bfd_link_pic (INFO) \
       && SYMBOL_REFERENCES_LOCAL_P ((INFO), (H))) \
       || (ELF_ST_VISIBILITY ((H)->other) \
	   && (H)->root.type == bfd_link_hash_undefweak))

/* TRUE if this symbol isn't defined by a shared object.  */
#define SYMBOL_DEFINED_NON_SHARED_P(H) \
  ((H)->def_regular \
   || (H)->root.linker_def \
   || (H)->root.ldscript_def \
   || ((struct elf_x86_link_hash_entry *) (H))->linker_def \
   || ELF_COMMON_DEF_P (H))

/* Return TRUE if the symbol described by a linker hash entry H is
   going to be absolute.  Similar to bfd_is_abs_symbol, but excluding
   all linker-script defined symbols.  */
#define ABS_SYMBOL_P(H) \
  (bfd_is_abs_symbol (&(H)->root) && !(H)->root.ldscript_def)

/* TRUE if relative relocation should be generated.  GOT reference to
   global symbol in PIC will lead to dynamic symbol.  It becomes a
   problem when "time" or "times" is defined as a variable in an
   executable, clashing with functions of the same name in libc.  If a
   symbol isn't undefined weak symbol, don't make it dynamic in PIC and
   generate relative relocation.   Don't generate relative relocation
   against non-preemptible absolute symbol.  */
#define GENERATE_RELATIVE_RELOC_P(INFO, H) \
  ((H)->dynindx == -1 \
   && !(H)->forced_local \
   && (H)->root.type != bfd_link_hash_undefweak \
   && bfd_link_pic (INFO) \
   && !ABS_SYMBOL_P (H))

/* TRUE if this is a pointer reference to a local IFUNC.  */
#define POINTER_LOCAL_IFUNC_P(INFO, H) \
  ((H)->dynindx == -1 \
   || (H)->forced_local \
   || bfd_link_executable (INFO))

/* TRUE if this is a PLT reference to a local IFUNC.  */
#define PLT_LOCAL_IFUNC_P(INFO, H) \
  ((H)->dynindx == -1 \
   || ((bfd_link_executable (INFO) \
	|| ELF_ST_VISIBILITY ((H)->other) != STV_DEFAULT) \
	&& (H)->def_regular \
	&& (H)->type == STT_GNU_IFUNC))

/* TRUE if TLS IE->LE transition is OK.  */
#define TLS_TRANSITION_IE_TO_LE_P(INFO, H, TLS_TYPE) \
  (bfd_link_executable (INFO) \
   && (H) != NULL \
   && (H)->dynindx == -1 \
   && (TLS_TYPE & GOT_TLS_IE))

/* Verify that the symbol has an entry in the procedure linkage table.  */
#define VERIFY_PLT_ENTRY(INFO, H, PLT, GOTPLT, RELPLT, LOCAL_UNDEFWEAK) \
  do \
    { \
      if (((H)->dynindx == -1 \
	   && !LOCAL_UNDEFWEAK \
	   && !(((H)->forced_local || bfd_link_executable (INFO)) \
		&& (H)->def_regular \
		&& (H)->type == STT_GNU_IFUNC)) \
	  || (PLT) == NULL \
	  || (GOTPLT) == NULL \
	  || (RELPLT) == NULL) \
	abort (); \
    } \
  while (0);

/* Verify that the symbol supports copy relocation.  */
#define VERIFY_COPY_RELOC(H, HTAB) \
  do \
    { \
      if ((H)->dynindx == -1 \
	  || ((H)->root.type != bfd_link_hash_defined \
	      && (H)->root.type != bfd_link_hash_defweak) \
	  || (HTAB)->elf.srelbss == NULL \
	  || (HTAB)->elf.sreldynrelro == NULL) \
	abort (); \
    } \
  while (0);

/* x86 ELF linker hash entry.  */

struct elf_x86_link_hash_entry
{
  struct elf_link_hash_entry elf;

  unsigned char tls_type;

  /* Bit 0: Symbol has no GOT nor PLT relocations.
     Bit 1: Symbol has non-GOT/non-PLT relocations in text sections.
     zero_undefweak is initialized to 1 and undefined weak symbol
     should be resolved to 0 if zero_undefweak > 0.  */
  unsigned int zero_undefweak : 2;

  /* Don't call finish_dynamic_symbol on this symbol.  */
  unsigned int no_finish_dynamic_symbol : 1;

  /* TRUE if symbol is __tls_get_addr.  */
  unsigned int tls_get_addr : 1;

  /* TRUE if symbol is defined as a protected symbol.  */
  unsigned int def_protected : 1;

  /* 0: Symbol references are unknown.
     1: Symbol references aren't local.
     2: Symbol references are local.
   */
  unsigned int local_ref : 2;

  /* TRUE if symbol is defined by linker.  */
  unsigned int linker_def : 1;

  /* TRUE if symbol is referenced by a non-GOT/non-PLT relocation in a
     relocatable object file without indirect external access marker.  */
  unsigned int non_got_ref_without_indirect_extern_access : 1;

  /* TRUE if symbol is referenced by R_386_GOTOFF relocation.  This is
     only used by i386.  */
  unsigned int gotoff_ref : 1;

  /* TRUE if a weak symbol with a real definition needs a copy reloc.
     When there is a weak symbol with a real definition, the processor
     independent code will have arranged for us to see the real
     definition first.  We need to copy the needs_copy bit from the
     real definition and check it when allowing copy reloc in PIE.  This
     is only used by x86-64.  */
  unsigned int needs_copy : 1;

  /* Information about the GOT PLT entry. Filled when there are both
     GOT and PLT relocations against the same function.  */
  union gotplt_union plt_got;

  /* Information about the second PLT entry.   */
  union gotplt_union plt_second;

  /* Offset of the GOTPLT entry reserved for the TLS descriptor,
     starting at the end of the jump table.  */
  bfd_vma tlsdesc_got;
};

struct elf_x86_lazy_plt_layout
{
  /* The first entry in a lazy procedure linkage table looks like this.  */
  const bfd_byte *plt0_entry;
  unsigned int plt0_entry_size;		 /* Size of PLT0 entry.  */

  /* Later entries in a lazy procedure linkage table look like this.  */
  const bfd_byte *plt_entry;
  unsigned int plt_entry_size;		/* Size of each PLT entry.  */

  /* The TLSDESC entry in a lazy procedure linkage table looks like
     this.  This is for x86-64 only.  */
  const bfd_byte *plt_tlsdesc_entry;
  unsigned int plt_tlsdesc_entry_size;	 /* Size of TLSDESC entry.  */

  /* Offsets into the TLSDESC entry that are to be replaced with
     GOT+8 and GOT+TDG.  These are for x86-64 only.  */
  unsigned int plt_tlsdesc_got1_offset;
  unsigned int plt_tlsdesc_got2_offset;

  /* Offset of the end of the PC-relative instructions containing
     plt_tlsdesc_got1_offset and plt_tlsdesc_got2_offset.  These
     are for x86-64 only.  */
  unsigned int plt_tlsdesc_got1_insn_end;
  unsigned int plt_tlsdesc_got2_insn_end;

  /* Offsets into plt0_entry that are to be replaced with GOT[1] and
     GOT[2].  */
  unsigned int plt0_got1_offset;
  unsigned int plt0_got2_offset;

  /* Offset of the end of the PC-relative instruction containing
     plt0_got2_offset.  This is for x86-64 only.  */
  unsigned int plt0_got2_insn_end;

  /* Offsets into plt_entry that are to be replaced with...  */
  unsigned int plt_got_offset;    /* ... address of this symbol in .got. */
  unsigned int plt_reloc_offset;  /* ... offset into relocation table. */
  unsigned int plt_plt_offset;    /* ... offset to start of .plt. */

  /* Length of the PC-relative instruction containing plt_got_offset.
     This is used for x86-64 only.  */
  unsigned int plt_got_insn_size;

  /* Offset of the end of the PC-relative jump to plt0_entry.  This is
     used for x86-64 only.  */
  unsigned int plt_plt_insn_end;

  /* Offset into plt_entry where the initial value of the GOT entry
     points.  */
  unsigned int plt_lazy_offset;

  /* The first entry in a PIC lazy procedure linkage table looks like
     this.  */
  const bfd_byte *pic_plt0_entry;

  /* Subsequent entries in a PIC lazy procedure linkage table look
     like this.  */
  const bfd_byte *pic_plt_entry;

  /* .eh_frame covering the lazy .plt section.  */
  const bfd_byte *eh_frame_plt;
  unsigned int eh_frame_plt_size;
};

struct elf_x86_non_lazy_plt_layout
{
  /* Entries in a non-lazy procedure linkage table look like this.  */
  const bfd_byte *plt_entry;
  /* Entries in a PIC non-lazy procedure linkage table look like this.
     This is only used for i386 where absolute PLT and PIC PLT are
     different.  */
  const bfd_byte *pic_plt_entry;

  unsigned int plt_entry_size;		/* Size of each PLT entry.  */

  /* Offsets into plt_entry that are to be replaced with...  */
  unsigned int plt_got_offset;    /* ... address of this symbol in .got. */

  /* Length of the PC-relative instruction containing plt_got_offset.
     This is used for x86-64 only.  */
  unsigned int plt_got_insn_size;

  /* .eh_frame covering the non-lazy .plt section.  */
  const bfd_byte *eh_frame_plt;
  unsigned int eh_frame_plt_size;
};

struct elf_x86_plt_layout
{
  /* The first entry in a lazy procedure linkage table looks like this.  */
  const bfd_byte *plt0_entry;
  /* Entries in a procedure linkage table look like this.  */
  const bfd_byte *plt_entry;
  unsigned int plt_entry_size;		/* Size of each PLT entry.  */

  /* 1 has PLT0.  */
  unsigned int has_plt0;

  /* Offsets into plt_entry that are to be replaced with...  */
  unsigned int plt_got_offset;    /* ... address of this symbol in .got. */

  /* Length of the PC-relative instruction containing plt_got_offset.
     This is only used for x86-64.  */
  unsigned int plt_got_insn_size;

  /* Alignment of the .iplt section.  */
  unsigned int iplt_alignment;

  /* .eh_frame covering the .plt section.  */
  const bfd_byte *eh_frame_plt;
  unsigned int eh_frame_plt_size;
};

/* Values in tls_type of x86 ELF linker hash entry.  */
#define GOT_UNKNOWN	0
#define GOT_NORMAL	1
#define GOT_TLS_GD	2
#define GOT_TLS_IE	4
#define GOT_TLS_IE_POS	5
#define GOT_TLS_IE_NEG	6
#define GOT_TLS_IE_BOTH 7
#define GOT_TLS_GDESC	8
#define GOT_ABS		9
#define GOT_TLS_GD_BOTH_P(type)	\
  ((type) == (GOT_TLS_GD | GOT_TLS_GDESC))
#define GOT_TLS_GD_P(type) \
  ((type) == GOT_TLS_GD || GOT_TLS_GD_BOTH_P (type))
#define GOT_TLS_GDESC_P(type) \
  ((type) == GOT_TLS_GDESC || GOT_TLS_GD_BOTH_P (type))
#define GOT_TLS_GD_ANY_P(type) \
  (GOT_TLS_GD_P (type) || GOT_TLS_GDESC_P (type))

#define elf_x86_hash_entry(ent) \
  ((struct elf_x86_link_hash_entry *)(ent))

/* x86 ELF linker hash table.  */

struct elf_x86_link_hash_table
{
  struct elf_link_hash_table elf;

  /* Short-cuts to get to dynamic linker sections.  */
  asection *interp;
  asection *plt_eh_frame;
  asection *plt_second;
  asection *plt_second_eh_frame;
  asection *plt_got;
  asection *plt_got_eh_frame;

  /* Parameters describing PLT generation, lazy or non-lazy.  */
  struct elf_x86_plt_layout plt;

  /* Parameters describing lazy PLT generation.  */
  const struct elf_x86_lazy_plt_layout *lazy_plt;

  /* Parameters describing non-lazy PLT generation.  */
  const struct elf_x86_non_lazy_plt_layout *non_lazy_plt;

  union
  {
    bfd_signed_vma refcount;
    bfd_vma offset;
  } tls_ld_or_ldm_got;

  /* The amount of space used by the jump slots in the GOT.  */
  bfd_vma sgotplt_jump_table_size;

  /* _TLS_MODULE_BASE_ symbol.  */
  struct bfd_link_hash_entry *tls_module_base;

  /* Used by local STT_GNU_IFUNC symbols.  */
  htab_t loc_hash_table;
  void * loc_hash_memory;

  /* The index of the next R_X86_64_JUMP_SLOT entry in .rela.plt.  */
  bfd_vma next_jump_slot_index;
  /* The index of the next R_X86_64_IRELATIVE entry in .rela.plt.  */
  bfd_vma next_irelative_index;

  /* The (unloaded but important) .rel.plt.unloaded section on VxWorks.
     This is used for i386 only.  */
  asection *srelplt2;

  /* The index of the next unused R_386_TLS_DESC slot in .rel.plt.  This
     is only used for i386.  */
  bfd_vma next_tls_desc_index;

   /* Value used to fill the unused bytes of the first PLT entry.  This
      is only used for i386.  */
  bfd_byte plt0_pad_byte;

  /* TRUE if GOT is referenced.  */
  unsigned int got_referenced : 1;

  /* TRUE if PLT is PC-relative.  PLT in PDE and PC-relative PLT in PIE
     can be used as function address.

     NB: i386 has non-PIC PLT and PIC PLT.  Only non-PIC PLT in PDE can
     be used as function address.  PIC PLT in PIE can't be used as
     function address.  */
  unsigned int pcrel_plt : 1;

  bfd_vma (*r_info) (bfd_vma, bfd_vma);
  bfd_vma (*r_sym) (bfd_vma);
  bool (*is_reloc_section) (const char *);
  unsigned int sizeof_reloc;
  unsigned int got_entry_size;
  unsigned int pointer_r_type;
  int dynamic_interpreter_size;
  const char *dynamic_interpreter;
  const char *tls_get_addr;

  /* Options passed from the linker.  */
  struct elf_linker_x86_params *params;
};

struct elf_x86_init_table
{
  /* The lazy PLT layout.  */
  const struct elf_x86_lazy_plt_layout *lazy_plt;

  /* The non-lazy PLT layout.  */
  const struct elf_x86_non_lazy_plt_layout *non_lazy_plt;

  /* The lazy PLT layout for IBT.  */
  const struct elf_x86_lazy_plt_layout *lazy_ibt_plt;

  /* The non-lazy PLT layout for IBT.  */
  const struct elf_x86_non_lazy_plt_layout *non_lazy_ibt_plt;

  bfd_byte plt0_pad_byte;

  bfd_vma (*r_info) (bfd_vma, bfd_vma);
  bfd_vma (*r_sym) (bfd_vma);
};

struct elf_x86_obj_tdata
{
  struct elf_obj_tdata root;

  /* tls_type for each local got entry.  */
  char *local_got_tls_type;

  /* GOTPLT entries for TLS descriptors.  */
  bfd_vma *local_tlsdesc_gotent;
};

enum elf_x86_plt_type
{
  plt_non_lazy = 0,
  plt_lazy = 1 << 0,
  plt_pic = 1 << 1,
  plt_second = 1 << 2,
  plt_unknown = -1
};

struct elf_x86_plt
{
  const char *name;
  asection *sec;
  bfd_byte *contents;
  enum elf_x86_plt_type type;
  unsigned int plt_got_offset;
  unsigned int plt_entry_size;
  unsigned int plt_got_insn_size;	/* Only used for x86-64.  */
  long count;
};

/* Set if a relocation is converted from a GOTPCREL relocation.  */
#define R_X86_64_converted_reloc_bit (1 << 7)

#define elf_x86_tdata(abfd) \
  ((struct elf_x86_obj_tdata *) (abfd)->tdata.any)

#define elf_x86_local_got_tls_type(abfd) \
  (elf_x86_tdata (abfd)->local_got_tls_type)

#define elf_x86_local_tlsdesc_gotent(abfd) \
  (elf_x86_tdata (abfd)->local_tlsdesc_gotent)

#define elf_x86_compute_jump_table_size(htab) \
  ((htab)->elf.srelplt->reloc_count * (htab)->got_entry_size)

#define is_x86_elf(bfd, htab)				\
  (bfd_get_flavour (bfd) == bfd_target_elf_flavour	\
   && elf_tdata (bfd) != NULL				\
   && elf_object_id (bfd) == (htab)->elf.hash_table_id)

extern bool _bfd_x86_elf_mkobject
  (bfd *);

extern void _bfd_x86_elf_set_tls_module_base
  (struct bfd_link_info *);

extern bfd_vma _bfd_x86_elf_dtpoff_base
  (struct bfd_link_info *);

extern bool _bfd_x86_elf_readonly_dynrelocs
  (struct elf_link_hash_entry *, void *);

extern struct elf_link_hash_entry * _bfd_elf_x86_get_local_sym_hash
  (struct elf_x86_link_hash_table *, bfd *, const Elf_Internal_Rela *,
   bool);

extern hashval_t _bfd_x86_elf_local_htab_hash
  (const void *);

extern int _bfd_x86_elf_local_htab_eq
  (const void *, const void *);

extern struct bfd_hash_entry * _bfd_x86_elf_link_hash_newfunc
  (struct bfd_hash_entry *, struct bfd_hash_table *, const char *);

extern struct bfd_link_hash_table * _bfd_x86_elf_link_hash_table_create
  (bfd *);

extern int _bfd_x86_elf_compare_relocs
  (const void *, const void *);

extern bool _bfd_x86_elf_link_check_relocs
  (bfd *, struct bfd_link_info *);

extern bool _bfd_elf_x86_valid_reloc_p
  (asection *, struct bfd_link_info *, struct elf_x86_link_hash_table *,
   const Elf_Internal_Rela *, struct elf_link_hash_entry *,
   Elf_Internal_Sym *, Elf_Internal_Shdr *, bool *);

extern bool _bfd_x86_elf_size_dynamic_sections
  (bfd *, struct bfd_link_info *);

extern struct elf_x86_link_hash_table *_bfd_x86_elf_finish_dynamic_sections
  (bfd *, struct bfd_link_info *);

extern bool _bfd_x86_elf_always_size_sections
  (bfd *, struct bfd_link_info *);

extern void _bfd_x86_elf_merge_symbol_attribute
  (struct elf_link_hash_entry *, unsigned int, bool, bool);

extern void _bfd_x86_elf_copy_indirect_symbol
  (struct bfd_link_info *, struct elf_link_hash_entry *,
   struct elf_link_hash_entry *);

extern bool _bfd_x86_elf_fixup_symbol
  (struct bfd_link_info *, struct elf_link_hash_entry *);

extern bool _bfd_x86_elf_hash_symbol
  (struct elf_link_hash_entry *);

extern bool _bfd_x86_elf_adjust_dynamic_symbol
  (struct bfd_link_info *, struct elf_link_hash_entry *);

extern void _bfd_x86_elf_hide_symbol
  (struct bfd_link_info *, struct elf_link_hash_entry *, bool);

extern bool _bfd_x86_elf_link_symbol_references_local
  (struct bfd_link_info *, struct elf_link_hash_entry *);

extern asection * _bfd_x86_elf_gc_mark_hook
  (asection *, struct bfd_link_info *, Elf_Internal_Rela *,
   struct elf_link_hash_entry *, Elf_Internal_Sym *);

extern long _bfd_x86_elf_get_synthetic_symtab
  (bfd *, long, long, bfd_vma, struct elf_x86_plt [], asymbol **,
   asymbol **);

extern enum elf_property_kind _bfd_x86_elf_parse_gnu_properties
  (bfd *, unsigned int, bfd_byte *, unsigned int);

extern bool _bfd_x86_elf_merge_gnu_properties
  (struct bfd_link_info *, bfd *, bfd *, elf_property *, elf_property *);

extern void _bfd_x86_elf_link_fixup_gnu_properties
  (struct bfd_link_info *, elf_property_list **);

extern bfd * _bfd_x86_elf_link_setup_gnu_properties
  (struct bfd_link_info *, struct elf_x86_init_table *);

extern void _bfd_x86_elf_link_fixup_ifunc_symbol
  (struct bfd_link_info *, struct elf_x86_link_hash_table *,
   struct elf_link_hash_entry *, Elf_Internal_Sym *sym);

extern void _bfd_x86_elf_link_report_relative_reloc
  (struct bfd_link_info *, asection *, struct elf_link_hash_entry *,
   Elf_Internal_Sym *, const char *, const void *);

#define bfd_elf64_mkobject \
  _bfd_x86_elf_mkobject
#define bfd_elf32_mkobject \
  _bfd_x86_elf_mkobject
#define bfd_elf64_bfd_link_hash_table_create \
  _bfd_x86_elf_link_hash_table_create
#define bfd_elf32_bfd_link_hash_table_create \
  _bfd_x86_elf_link_hash_table_create
#define bfd_elf64_bfd_link_check_relocs	\
  _bfd_x86_elf_link_check_relocs
#define bfd_elf32_bfd_link_check_relocs \
  _bfd_x86_elf_link_check_relocs

#define elf_backend_size_dynamic_sections \
  _bfd_x86_elf_size_dynamic_sections
#define elf_backend_always_size_sections \
  _bfd_x86_elf_always_size_sections
#define elf_backend_merge_symbol_attribute \
  _bfd_x86_elf_merge_symbol_attribute
#define elf_backend_copy_indirect_symbol \
  _bfd_x86_elf_copy_indirect_symbol
#define elf_backend_fixup_symbol \
  _bfd_x86_elf_fixup_symbol
#define elf_backend_hash_symbol \
  _bfd_x86_elf_hash_symbol
#define elf_backend_adjust_dynamic_symbol \
  _bfd_x86_elf_adjust_dynamic_symbol
#define elf_backend_gc_mark_hook \
  _bfd_x86_elf_gc_mark_hook
#define elf_backend_omit_section_dynsym \
  _bfd_elf_omit_section_dynsym_all
#define elf_backend_parse_gnu_properties \
  _bfd_x86_elf_parse_gnu_properties
#define elf_backend_merge_gnu_properties \
  _bfd_x86_elf_merge_gnu_properties
#define elf_backend_fixup_gnu_properties \
  _bfd_x86_elf_link_fixup_gnu_properties