228 lines
7.2 KiB
C
228 lines
7.2 KiB
C
/* VxWorks support for ELF
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Copyright 2005, 2007 Free Software Foundation, Inc.
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This file is part of BFD, the Binary File Descriptor library.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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/* This file provides routines used by all VxWorks targets. */
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#include "sysdep.h"
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#include "bfd.h"
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#include "libbfd.h"
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#include "elf-bfd.h"
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#include "elf-vxworks.h"
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/* Return true if symbol NAME, as defined by ABFD, is one of the special
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__GOTT_BASE__ or __GOTT_INDEX__ symbols. */
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static bfd_boolean
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elf_vxworks_gott_symbol_p (bfd *abfd, const char *name)
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{
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char leading;
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leading = bfd_get_symbol_leading_char (abfd);
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if (leading)
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{
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if (*name != leading)
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return FALSE;
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name++;
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}
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return (strcmp (name, "__GOTT_BASE__") == 0
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|| strcmp (name, "__GOTT_INDEX__") == 0);
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}
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/* Tweak magic VxWorks symbols as they are loaded. */
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bfd_boolean
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elf_vxworks_add_symbol_hook (bfd *abfd,
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struct bfd_link_info *info,
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Elf_Internal_Sym *sym,
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const char **namep,
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flagword *flagsp,
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asection **secp ATTRIBUTE_UNUSED,
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bfd_vma *valp ATTRIBUTE_UNUSED)
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{
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/* Ideally these "magic" symbols would be exported by libc.so.1
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which would be found via a DT_NEEDED tag, and then handled
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specially by the linker at runtime. Except shared libraries
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don't even link to libc.so.1 by default...
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If the symbol is imported from, or will be put in a shared library,
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give the symbol weak binding to get the desired samantics.
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This transformation will be undone in
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elf_i386_vxworks_link_output_symbol_hook. */
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if ((info->shared || abfd->flags & DYNAMIC)
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&& elf_vxworks_gott_symbol_p (abfd, *namep))
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{
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sym->st_info = ELF_ST_INFO (STB_WEAK, ELF_ST_TYPE (sym->st_info));
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*flagsp |= BSF_WEAK;
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}
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return TRUE;
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}
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/* Perform VxWorks-specific handling of the create_dynamic_sections hook.
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When creating an executable, set *SRELPLT2_OUT to the .rel(a).plt.unloaded
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section. */
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bfd_boolean
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elf_vxworks_create_dynamic_sections (bfd *dynobj, struct bfd_link_info *info,
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asection **srelplt2_out)
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{
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struct elf_link_hash_table *htab;
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const struct elf_backend_data *bed;
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asection *s;
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htab = elf_hash_table (info);
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bed = get_elf_backend_data (dynobj);
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if (!info->shared)
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{
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s = bfd_make_section_with_flags (dynobj,
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bed->default_use_rela_p
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? ".rela.plt.unloaded"
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: ".rel.plt.unloaded",
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SEC_HAS_CONTENTS | SEC_IN_MEMORY
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| SEC_READONLY | SEC_LINKER_CREATED);
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if (s == NULL
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|| !bfd_set_section_alignment (dynobj, s, bed->s->log_file_align))
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return FALSE;
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*srelplt2_out = s;
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}
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/* Mark the GOT and PLT symbols as having relocations; they might
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not, but we won't know for sure until we build the GOT in
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finish_dynamic_symbol. Also make sure that the GOT symbol
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is entered into the dynamic symbol table; the loader uses it
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to initialize __GOTT_BASE__[__GOTT_INDEX__]. */
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if (htab->hgot)
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{
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htab->hgot->indx = -2;
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htab->hgot->other &= ~ELF_ST_VISIBILITY (-1);
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htab->hgot->forced_local = 0;
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if (!bfd_elf_link_record_dynamic_symbol (info, htab->hgot))
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return FALSE;
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}
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if (htab->hplt)
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{
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htab->hplt->indx = -2;
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htab->hplt->type = STT_FUNC;
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}
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return TRUE;
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}
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/* Tweak magic VxWorks symbols as they are written to the output file. */
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bfd_boolean
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elf_vxworks_link_output_symbol_hook (struct bfd_link_info *info
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ATTRIBUTE_UNUSED,
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const char *name,
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Elf_Internal_Sym *sym,
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asection *input_sec ATTRIBUTE_UNUSED,
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struct elf_link_hash_entry *h)
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{
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/* Reverse the effects of the hack in elf_vxworks_add_symbol_hook. */
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if (h
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&& h->root.type == bfd_link_hash_undefweak
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&& elf_vxworks_gott_symbol_p (h->root.u.undef.abfd, name))
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sym->st_info = ELF_ST_INFO (STB_GLOBAL, ELF_ST_TYPE (sym->st_info));
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return TRUE;
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}
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/* Copy relocations into the output file. Fixes up relocations againt PLT
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entries, then calls the generic routine. */
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bfd_boolean
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elf_vxworks_emit_relocs (bfd *output_bfd,
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asection *input_section,
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Elf_Internal_Shdr *input_rel_hdr,
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Elf_Internal_Rela *internal_relocs,
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struct elf_link_hash_entry **rel_hash)
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{
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const struct elf_backend_data *bed;
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Elf_Internal_Rela *irela;
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Elf_Internal_Rela *irelaend;
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int j;
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bed = get_elf_backend_data (output_bfd);
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irela = internal_relocs;
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irelaend = irela + (NUM_SHDR_ENTRIES (input_rel_hdr)
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* bed->s->int_rels_per_ext_rel);
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while (irela < irelaend)
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{
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if ((output_bfd->flags & (DYNAMIC|EXEC_P))
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&& *rel_hash
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&& (*rel_hash)->def_dynamic
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&& !(*rel_hash)->def_regular
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&& ((*rel_hash)->root.type == bfd_link_hash_defined
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|| (*rel_hash)->root.type == bfd_link_hash_defweak)
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&& (*rel_hash)->root.u.def.section->output_section != NULL)
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{
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/* This is a relocation from an executable or shared library
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against a symbol in a different shared library. We are
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creating a definition in the output file but it does not come
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from any of our normal (.o) files. ie. a PLT stub.
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Normally this would be a relocation against against SHN_UNDEF
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with the VMA of the PLT stub. This upsets the VxWorks loader.
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Convert it to a section-relative relocation.
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This gets some other symbols (for instance .dynbss),
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but is conservatively correct. */
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for (j = 0; j < bed->s->int_rels_per_ext_rel; j++)
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{
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asection *sec = (*rel_hash)->root.u.def.section;
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int this_idx = sec->output_section->target_index;
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irela[j].r_info = ELF32_R_INFO (this_idx,
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ELF32_R_TYPE (irela[j].r_info));
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irela[j].r_addend += (*rel_hash)->root.u.def.value;
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irela[j].r_addend += sec->output_offset;
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}
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/* Stop the generic routine adjusting this entry. */
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*rel_hash = NULL;
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}
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irela += bed->s->int_rels_per_ext_rel;
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rel_hash++;
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}
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return _bfd_elf_link_output_relocs (output_bfd, input_section,
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input_rel_hdr, internal_relocs,
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rel_hash);
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}
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/* Set the sh_link and sh_info fields on the static plt relocation secton. */
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void
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elf_vxworks_final_write_processing (bfd *abfd,
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bfd_boolean linker ATTRIBUTE_UNUSED)
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{
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asection * sec;
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struct bfd_elf_section_data *d;
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sec = bfd_get_section_by_name (abfd, ".rel.plt.unloaded");
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if (!sec)
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sec = bfd_get_section_by_name (abfd, ".rela.plt.unloaded");
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if (!sec)
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return;
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d = elf_section_data (sec);
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d->this_hdr.sh_link = elf_tdata (abfd)->symtab_section;
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sec = bfd_get_section_by_name (abfd, ".plt");
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if (sec)
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d->this_hdr.sh_info = elf_section_data (sec)->this_idx;
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}
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