/* x86 specific support for ELF
- Copyright (C) 2017-2018 Free Software Foundation, Inc.
+ Copyright (C) 2017-2019 Free Software Foundation, Inc.
This file is part of BFD, the Binary File Descriptor library.
return 0;
}
+/* Mark symbol, NAME, as locally defined by linker if it is referenced
+ and not defined in a relocatable object file. */
+
+static void
+elf_x86_linker_defined (struct bfd_link_info *info, const char *name)
+{
+ struct elf_link_hash_entry *h;
+
+ h = elf_link_hash_lookup (elf_hash_table (info), name,
+ FALSE, FALSE, FALSE);
+ if (h == NULL)
+ return;
+
+ while (h->root.type == bfd_link_hash_indirect)
+ h = (struct elf_link_hash_entry *) h->root.u.i.link;
+
+ if (h->root.type == bfd_link_hash_new
+ || h->root.type == bfd_link_hash_undefined
+ || h->root.type == bfd_link_hash_undefweak
+ || h->root.type == bfd_link_hash_common
+ || (!h->def_regular && h->def_dynamic))
+ {
+ elf_x86_hash_entry (h)->local_ref = 2;
+ elf_x86_hash_entry (h)->linker_def = 1;
+ }
+}
+
+/* Hide a linker-defined symbol, NAME, with hidden visibility. */
+
+static void
+elf_x86_hide_linker_defined (struct bfd_link_info *info,
+ const char *name)
+{
+ struct elf_link_hash_entry *h;
+
+ h = elf_link_hash_lookup (elf_hash_table (info), name,
+ FALSE, FALSE, FALSE);
+ if (h == NULL)
+ return;
+
+ while (h->root.type == bfd_link_hash_indirect)
+ h = (struct elf_link_hash_entry *) h->root.u.i.link;
+
+ if (ELF_ST_VISIBILITY (h->other) == STV_INTERNAL
+ || ELF_ST_VISIBILITY (h->other) == STV_HIDDEN)
+ _bfd_elf_link_hash_hide_symbol (info, h, TRUE);
+}
+
bfd_boolean
_bfd_x86_elf_link_check_relocs (bfd *abfd, struct bfd_link_info *info)
{
/* "__ehdr_start" will be defined by linker as a hidden symbol
later if it is referenced and not defined. */
- h = elf_link_hash_lookup (elf_hash_table (info),
- "__ehdr_start",
- FALSE, FALSE, FALSE);
- if (h != NULL
- && (h->root.type == bfd_link_hash_new
- || h->root.type == bfd_link_hash_undefined
- || h->root.type == bfd_link_hash_undefweak
- || h->root.type == bfd_link_hash_common))
+ elf_x86_linker_defined (info, "__ehdr_start");
+
+ if (bfd_link_executable (info))
{
- elf_x86_hash_entry (h)->local_ref = 2;
- elf_x86_hash_entry (h)->linker_def = 1;
+ /* References to __bss_start, _end and _edata should be
+ locally resolved within executables. */
+ elf_x86_linker_defined (info, "__bss_start");
+ elf_x86_linker_defined (info, "_end");
+ elf_x86_linker_defined (info, "_edata");
+ }
+ else
+ {
+ /* Hide hidden __bss_start, _end and _edata in shared
+ libraries. */
+ elf_x86_hide_linker_defined (info, "__bss_start");
+ elf_x86_hide_linker_defined (info, "_end");
+ elf_x86_hide_linker_defined (info, "_edata");
}
}
}
if ((s->flags & SEC_HAS_CONTENTS) == 0)
continue;
+ /* NB: Initially, the iplt section has minimal alignment to
+ avoid moving dot of the following section backwards when
+ it is empty. Update its section alignment now since it
+ is non-empty. */
+ if (s == htab->elf.iplt)
+ bfd_set_section_alignment (s->owner, s,
+ htab->plt.iplt_alignment);
+
/* Allocate memory for the section contents. We use bfd_zalloc
here in case unused entries are not reclaimed before the
section's contents are written out. This should not happen,
return TRUE;
}
+/* Change the STT_GNU_IFUNC symbol defined in position-dependent
+ executable into the normal function symbol and set its address
+ to its PLT entry, which should be resolved by R_*_IRELATIVE at
+ run-time. */
+
+void
+_bfd_x86_elf_link_fixup_ifunc_symbol (struct bfd_link_info *info,
+ struct elf_x86_link_hash_table *htab,
+ struct elf_link_hash_entry *h,
+ Elf_Internal_Sym *sym)
+{
+ if (bfd_link_pde (info)
+ && h->def_regular
+ && h->dynindx != -1
+ && h->plt.offset != (bfd_vma) -1
+ && h->type == STT_GNU_IFUNC
+ && h->pointer_equality_needed)
+ {
+ asection *plt_s;
+ bfd_vma plt_offset;
+ bfd *output_bfd = info->output_bfd;
+
+ if (htab->plt_second)
+ {
+ struct elf_x86_link_hash_entry *eh
+ = (struct elf_x86_link_hash_entry *) h;
+
+ plt_s = htab->plt_second;
+ plt_offset = eh->plt_second.offset;
+ }
+ else
+ {
+ plt_s = htab->elf.splt;
+ plt_offset = h->plt.offset;
+ }
+
+ sym->st_size = 0;
+ sym->st_info = ELF_ST_INFO (ELF_ST_BIND (sym->st_info), STT_FUNC);
+ sym->st_shndx
+ = _bfd_elf_section_from_bfd_section (output_bfd,
+ plt_s->output_section);
+ sym->st_value = (plt_s->output_section->vma
+ + plt_s->output_offset + plt_offset);
+ }
+}
+
/* Return TRUE if symbol should be hashed in the `.gnu.hash' section. */
bfd_boolean
&& htab->interp == NULL)
|| info->dynamic_undefined_weak == 0))
|| ((h->def_regular || ELF_COMMON_DEF_P (h))
- && h->versioned == unversioned
&& info->version_info != NULL
- && bfd_hide_sym_by_version (info->version_info,
- h->root.root.string)))
+ && _bfd_elf_link_hide_sym_by_version (info, h)))
{
eh->local_ref = 2;
return TRUE;
{
elf_property *prop;
- switch (type)
+ if (type == GNU_PROPERTY_X86_COMPAT_ISA_1_USED
+ || type == GNU_PROPERTY_X86_COMPAT_ISA_1_NEEDED
+ || (type >= GNU_PROPERTY_X86_UINT32_AND_LO
+ && type <= GNU_PROPERTY_X86_UINT32_AND_HI)
+ || (type >= GNU_PROPERTY_X86_UINT32_OR_LO
+ && type <= GNU_PROPERTY_X86_UINT32_OR_HI)
+ || (type >= GNU_PROPERTY_X86_UINT32_OR_AND_LO
+ && type <= GNU_PROPERTY_X86_UINT32_OR_AND_HI))
{
- case GNU_PROPERTY_X86_ISA_1_USED:
- case GNU_PROPERTY_X86_ISA_1_NEEDED:
- case GNU_PROPERTY_X86_FEATURE_1_AND:
if (datasz != 4)
{
_bfd_error_handler
- ((type == GNU_PROPERTY_X86_ISA_1_USED
- ? _("error: %pB: <corrupt x86 ISA used size: 0x%x>")
- : (type == GNU_PROPERTY_X86_ISA_1_NEEDED
- ? _("error: %pB: <corrupt x86 ISA needed size: 0x%x>")
- : _("error: %pB: <corrupt x86 feature size: 0x%x>"))),
- abfd, datasz);
+ (_("error: %pB: <corrupt x86 property (0x%x) size: 0x%x>"),
+ abfd, type, datasz);
return property_corrupt;
}
prop = _bfd_elf_get_property (abfd, type, datasz);
- /* Combine properties of the same type. */
prop->u.number |= bfd_h_get_32 (abfd, ptr);
prop->pr_kind = property_number;
- break;
-
- default:
- return property_ignored;
+ return property_number;
}
- return property_number;
+ return property_ignored;
}
/* Merge x86 GNU property BPROP with APROP. If APROP isn't NULL,
bfd_boolean updated = FALSE;
unsigned int pr_type = aprop != NULL ? aprop->pr_type : bprop->pr_type;
- switch (pr_type)
+ if (pr_type == GNU_PROPERTY_X86_COMPAT_ISA_1_USED
+ || (pr_type >= GNU_PROPERTY_X86_UINT32_OR_AND_LO
+ && pr_type <= GNU_PROPERTY_X86_UINT32_OR_AND_HI))
{
- case GNU_PROPERTY_X86_ISA_1_USED:
- case GNU_PROPERTY_X86_ISA_1_NEEDED:
- if (aprop != NULL && bprop != NULL)
+ if (aprop == NULL || bprop == NULL)
+ {
+ /* Only one of APROP and BPROP can be NULL. */
+ if (aprop != NULL)
+ {
+ /* Remove this property since the other input file doesn't
+ have it. */
+ aprop->pr_kind = property_remove;
+ updated = TRUE;
+ }
+ }
+ else
{
number = aprop->u.number;
aprop->u.number = number | bprop->u.number;
updated = number != (unsigned int) aprop->u.number;
}
+ return updated;
+ }
+ else if (pr_type == GNU_PROPERTY_X86_COMPAT_ISA_1_NEEDED
+ || (pr_type >= GNU_PROPERTY_X86_UINT32_OR_LO
+ && pr_type <= GNU_PROPERTY_X86_UINT32_OR_HI))
+ {
+ if (aprop != NULL && bprop != NULL)
+ {
+ number = aprop->u.number;
+ aprop->u.number = number | bprop->u.number;
+ /* Remove the property if all bits are empty. */
+ if (aprop->u.number == 0)
+ {
+ aprop->pr_kind = property_remove;
+ updated = TRUE;
+ }
+ else
+ updated = number != (unsigned int) aprop->u.number;
+ }
else
{
- /* Return TRUE if APROP is NULL to indicate that BPROP should
- be added to ABFD. */
- updated = aprop == NULL;
+ /* Only one of APROP and BPROP can be NULL. */
+ if (aprop != NULL)
+ {
+ if (aprop->u.number == 0)
+ {
+ /* Remove APROP if all bits are empty. */
+ aprop->pr_kind = property_remove;
+ updated = TRUE;
+ }
+ }
+ else
+ {
+ /* Return TRUE if APROP is NULL and all bits of BPROP
+ aren't empty to indicate that BPROP should be added
+ to ABFD. */
+ updated = bprop->u.number != 0;
+ }
}
- break;
-
- case GNU_PROPERTY_X86_FEATURE_1_AND:
+ return updated;
+ }
+ else if (pr_type >= GNU_PROPERTY_X86_UINT32_AND_LO
+ && pr_type <= GNU_PROPERTY_X86_UINT32_AND_HI)
+ {
/* Only one of APROP and BPROP can be NULL:
1. APROP & BPROP when both APROP and BPROP aren't NULL.
2. If APROP is NULL, remove x86 feature.
updated = TRUE;
}
}
- break;
-
- default:
+ return updated;
+ }
+ else
+ {
/* Never should happen. */
abort ();
}
break;
}
- if (ebfd != NULL && features)
+ bed = get_elf_backend_data (info->output_bfd);
+
+ htab = elf_x86_hash_table (info, bed->target_id);
+ if (htab == NULL)
+ return pbfd;
+
+ if (ebfd != NULL)
{
- /* If features is set, add GNU_PROPERTY_X86_FEATURE_1_IBT and
- GNU_PROPERTY_X86_FEATURE_1_SHSTK. */
- prop = _bfd_elf_get_property (ebfd,
- GNU_PROPERTY_X86_FEATURE_1_AND,
- 4);
- prop->u.number |= features;
- prop->pr_kind = property_number;
+ prop = NULL;
+ if (features)
+ {
+ /* If features is set, add GNU_PROPERTY_X86_FEATURE_1_IBT and
+ GNU_PROPERTY_X86_FEATURE_1_SHSTK. */
+ prop = _bfd_elf_get_property (ebfd,
+ GNU_PROPERTY_X86_FEATURE_1_AND,
+ 4);
+ prop->u.number |= features;
+ prop->pr_kind = property_number;
+ }
/* Create the GNU property note section if needed. */
- if (pbfd == NULL)
+ if (prop != NULL && pbfd == NULL)
{
sec = bfd_make_section_with_flags (ebfd,
NOTE_GNU_PROPERTY_SECTION_NAME,
pbfd = _bfd_elf_link_setup_gnu_properties (info);
- bed = get_elf_backend_data (info->output_bfd);
-
- htab = elf_x86_hash_table (info, bed->target_id);
- if (htab == NULL)
- return pbfd;
-
htab->r_info = init_table->r_info;
htab->r_sym = init_table->r_sym;
}
}
- if (normal_target)
+ /* The .iplt section is used for IFUNC symbols in static
+ executables. */
+ sec = htab->elf.iplt;
+ if (sec != NULL)
{
- /* The .iplt section is used for IFUNC symbols in static
- executables. */
- sec = htab->elf.iplt;
- if (sec != NULL
- && !bfd_set_section_alignment (sec->owner, sec,
- plt_alignment))
+ /* NB: Delay setting its alignment until we know it is non-empty.
+ Otherwise an empty iplt section may change vma and lma of the
+ following sections, which triggers moving dot of the following
+ section backwards, resulting in a warning and section lma not
+ being set properly. It later leads to a "File truncated"
+ error. */
+ if (!bfd_set_section_alignment (sec->owner, sec, 0))
goto error_alignment;
+
+ htab->plt.iplt_alignment = (normal_target
+ ? plt_alignment
+ : bed->plt_alignment);
}
return pbfd;
}
+
+/* Fix up x86 GNU properties. */
+
+void
+_bfd_x86_elf_link_fixup_gnu_properties
+ (struct bfd_link_info *info ATTRIBUTE_UNUSED,
+ elf_property_list **listp)
+{
+ elf_property_list *p;
+
+ for (p = *listp; p; p = p->next)
+ {
+ unsigned int type = p->property.pr_type;
+ if (type == GNU_PROPERTY_X86_COMPAT_ISA_1_USED
+ || type == GNU_PROPERTY_X86_COMPAT_ISA_1_NEEDED
+ || (type >= GNU_PROPERTY_X86_UINT32_AND_LO
+ && type <= GNU_PROPERTY_X86_UINT32_AND_HI)
+ || (type >= GNU_PROPERTY_X86_UINT32_OR_LO
+ && type <= GNU_PROPERTY_X86_UINT32_OR_HI)
+ || (type >= GNU_PROPERTY_X86_UINT32_OR_AND_LO
+ && type <= GNU_PROPERTY_X86_UINT32_OR_AND_HI))
+ {
+ if (p->property.u.number == 0
+ && (type == GNU_PROPERTY_X86_COMPAT_ISA_1_NEEDED
+ || (type >= GNU_PROPERTY_X86_UINT32_AND_LO
+ && type <= GNU_PROPERTY_X86_UINT32_AND_HI)
+ || (type >= GNU_PROPERTY_X86_UINT32_OR_LO
+ && type <= GNU_PROPERTY_X86_UINT32_OR_HI)))
+ {
+ /* Remove empty property. */
+ *listp = p->next;
+ continue;
+ }
+
+ listp = &p->next;
+ }
+ else if (type > GNU_PROPERTY_HIPROC)
+ {
+ /* The property list is sorted in order of type. */
+ break;
+ }
+ }
+}