forked from Imagelibrary/binutils-gdb
2009-06-17 H.J. Lu <hongjiu.lu@intel.com>
* elf-bfd.h (_bfd_elf_allocate_ifunc_dyn_relocs): New. * elf-ifunc.c (_bfd_elf_allocate_ifunc_dyn_relocs): Likewise. * elf32-i386.c (elf_i386_allocate_dynrelocs): Use it. * elf64-x86-64.c (elf64_x86_64_allocate_dynrelocs): Likewise. 2009-06-17 H.J. Lu <hongjiu.lu@intel.com> * elf-bfd.h (_bfd_elf_create_ifunc_dyn_reloc): New. * elf-ifunc.c (_bfd_elf_create_ifunc_dyn_reloc): Likewise. * elf32-i386.c (elf_i386_check_relocs): Use it. * elf64-x86-64.c (elf64_x86_64_check_relocs): Likewise. 2009-06-17 H.J. Lu <hongjiu.lu@intel.com> * elf-bfd.h (elf_dyn_relocs): New. * elf32-i386.c (elf_i386_dyn_relocs): Removed. (elf_i386_link_hash_entry): Replace elf_i386_dyn_relocs with elf_dyn_relocs. (elf_i386_copy_indirect_symbol): Likewise. (elf_i386_check_relocs): Likewise. (elf_i386_gc_sweep_hook): Likewise. (elf_i386_allocate_dynrelocs): Likewise. (elf_i386_readonly_dynrelocs): Likewise. (elf_i386_size_dynamic_sections): Likewise. * elf64-x86-64.c (elf64_x86_64_dyn_relocs): Removed. (elf64_x86_64_link_hash_entry): Replace elf64_x86_64_dyn_relocs with elf_dyn_relocs. (elf64_x86_64_copy_indirect_symbol): Updated. (elf64_x86_64_check_relocs): Likewise. (elf64_x86_64_gc_sweep_hook): Likewise. (elf64_x86_64_adjust_dynamic_symbol): Likewise. (elf64_x86_64_allocate_dynrelocs): Likewise. (elf64_x86_64_readonly_dynrelocs): Likewise. (elf64_x86_64_size_dynamic_sections): Likewise.
This commit is contained in:
H.J. Lu
182
bfd/elf-ifunc.c
182
bfd/elf-ifunc.c
@@ -103,3 +103,185 @@ _bfd_elf_create_ifunc_sections (bfd *abfd, struct bfd_link_info *info)
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return TRUE;
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}
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/* For a STT_GNU_IFUNC symbol, create a dynamic reloc section, SRELOC,
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for the input section, SEC, and append this reloc to HEAD. */
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asection *
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_bfd_elf_create_ifunc_dyn_reloc (bfd *abfd, struct bfd_link_info *info,
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asection *sec, asection *sreloc,
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struct elf_dyn_relocs **head)
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{
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struct elf_dyn_relocs *p;
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struct elf_link_hash_table *htab = elf_hash_table (info);
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if (sreloc == NULL)
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{
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const struct elf_backend_data *bed = get_elf_backend_data (abfd);
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if (htab->dynobj == NULL)
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htab->dynobj = abfd;
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sreloc = _bfd_elf_make_dynamic_reloc_section (sec, htab->dynobj,
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bed->s->log_file_align,
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abfd,
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bed->rela_plts_and_copies_p);
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if (sreloc == NULL)
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return NULL;
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}
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p = *head;
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if (p == NULL || p->sec != sec)
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{
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bfd_size_type amt = sizeof *p;
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p = ((struct elf_dyn_relocs *) bfd_alloc (htab->dynobj, amt));
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if (p == NULL)
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return NULL;
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p->next = *head;
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*head = p;
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p->sec = sec;
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p->count = 0;
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p->pc_count = 0;
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}
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p->count += 1;
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return sreloc;
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}
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/* Allocate space in .plt, .got and associated reloc sections for
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dynamic relocs against a STT_GNU_IFUNC symbol definition. */
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bfd_boolean
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_bfd_elf_allocate_ifunc_dyn_relocs (struct bfd_link_info *info,
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struct elf_link_hash_entry *h,
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struct elf_dyn_relocs **head,
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unsigned int plt_entry_size,
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unsigned int got_entry_size)
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{
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asection *plt, *gotplt, *relplt;
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struct elf_dyn_relocs *p;
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unsigned int sizeof_reloc;
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const struct elf_backend_data *bed;
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struct elf_link_hash_table *htab;
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/* When a shared library references a STT_GNU_IFUNC symbol defined
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in executable, the address of the resolved function may be used.
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But in non-shared executable, the address of its .plt slot may
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be used. Pointer equality may not work correctly. PIE should
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be used if pointer equality is required here. */
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if (!info->shared
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&& (h->dynindx != -1
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|| info->export_dynamic)
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&& h->pointer_equality_needed)
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{
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info->callbacks->einfo
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(_("%F%P: dynamic STT_GNU_IFUNC symbol `%s' with pointer "
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"equality in `%B' can not be used when making an "
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"executable; recompile with -fPIE and relink with -pie\n"),
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h->root.root.string,
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h->root.u.def.section->owner);
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bfd_set_error (bfd_error_bad_value);
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return FALSE;
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}
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/* Return and discard space for dynamic relocations against it if
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it is never referenced in a non-shared object. */
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if (!h->ref_regular)
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{
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if (h->plt.refcount > 0
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|| h->got.refcount > 0)
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abort ();
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h->got.offset = (bfd_vma) -1;
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*head = NULL;
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return TRUE;
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}
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bed = get_elf_backend_data (info->output_bfd);
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if (bed->rela_plts_and_copies_p)
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sizeof_reloc = bed->s->sizeof_rela;
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else
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sizeof_reloc = bed->s->sizeof_rel;
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htab = elf_hash_table (info);
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/* When building a static executable, use .iplt, .igot.plt and
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.rel[a].iplt sections for STT_GNU_IFUNC symbols. */
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if (htab->splt != NULL)
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{
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plt = htab->splt;
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gotplt = htab->sgotplt;
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relplt = htab->srelplt;
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/* If this is the first .plt entry, make room for the special
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first entry. */
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if (plt->size == 0)
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plt->size += plt_entry_size;
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}
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else
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{
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plt = htab->iplt;
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gotplt = htab->igotplt;
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relplt = htab->irelplt;
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}
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/* Don't update value of STT_GNU_IFUNC symbol to PLT. We need
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the original value for R_*_IRELATIVE. */
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h->plt.offset = plt->size;
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/* Make room for this entry in the .plt/.iplt section. */
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plt->size += plt_entry_size;
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/* We also need to make an entry in the .got.plt/.got.iplt section,
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which will be placed in the .got section by the linker script. */
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gotplt->size += got_entry_size;
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/* We also need to make an entry in the .rel[a].plt/.rel[a].iplt
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section. */
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relplt->size += sizeof_reloc;
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relplt->reloc_count++;
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/* We need dynamic relocation for STT_GNU_IFUNC symbol only when
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there is a non-GOT reference in a shared object. */
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if (!info->shared
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|| !h->non_got_ref)
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*head = NULL;
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/* Finally, allocate space. */
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for (p = *head; p != NULL; p = p->next)
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htab->irelifunc->size += p->count * sizeof_reloc;
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/* For STT_GNU_IFUNC symbol, .got.plt has the real function addres
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and .got has the PLT entry adddress. We will load the GOT entry
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with the PLT entry in finish_dynamic_symbol if it is used. For
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branch, it uses .got.plt. For symbol value,
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1. Use .got.plt in a shared object if it is forced local or not
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dynamic.
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2. Use .got.plt in a non-shared object if pointer equality isn't
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needed.
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3. Use .got.plt in PIE.
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4. Use .got.plt if .got isn't used.
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5. Otherwise use .got so that it can be shared among different
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objects at run-time.
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We only need to relocate .got entry in shared object. */
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if ((info->shared
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&& (h->dynindx == -1
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|| h->forced_local))
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|| (!info->shared
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&& !h->pointer_equality_needed)
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|| (info->executable && info->shared)
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|| htab->sgot == NULL)
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{
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/* Use .got.plt. */
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h->got.offset = (bfd_vma) -1;
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}
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else
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{
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h->got.offset = htab->sgot->size;
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htab->sgot->size += got_entry_size;
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if (info->shared)
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htab->srelgot->size += sizeof_reloc;
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}
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return TRUE;
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}
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