#define elf_backend_arch_data &elf_x86_64_arch_bed
+/* Is a undefined weak symbol which is resolved to 0. Reference to an
+ undefined weak symbol is resolved to 0 when building executable if
+ it isn't dynamic and
+ 1. Has non-GOT/non-PLT relocations in text section. Or
+ 2. Has no GOT/PLT relocation.
+ */
+#define UNDEFINED_WEAK_RESOLVED_TO_ZERO(INFO, EH) \
+ ((EH)->elf.root.type == bfd_link_hash_undefweak \
+ && bfd_link_executable (INFO) \
+ && (elf_x86_64_hash_table (INFO)->interp == NULL \
+ || !(EH)->has_got_reloc \
+ || (EH)->has_non_got_reloc \
+ || !(INFO)->dynamic_undefined_weak))
+
/* x86-64 ELF linker hash entry. */
struct elf_x86_64_link_hash_entry
/* TRUE if symbol has at least one BND relocation. */
unsigned int has_bnd_reloc : 1;
+ /* TRUE if symbol has GOT or PLT relocations. */
+ unsigned int has_got_reloc : 1;
+
+ /* TRUE if symbol has non-GOT/non-PLT relocations in text sections. */
+ unsigned int has_non_got_reloc : 1;
+
/* Reference count of C/C++ function pointer relocations in read-write
section which can be resolved at run-time. */
bfd_signed_vma func_pointer_refcount;
struct elf_link_hash_table elf;
/* Short-cuts to get to dynamic linker sections. */
+ asection *interp;
asection *sdynbss;
asection *srelbss;
asection *plt_eh_frame;
eh->tls_type = GOT_UNKNOWN;
eh->needs_copy = 0;
eh->has_bnd_reloc = 0;
+ eh->has_got_reloc = 0;
+ eh->has_non_got_reloc = 0;
eh->func_pointer_refcount = 0;
eh->plt_bnd.offset = (bfd_vma) -1;
eh->plt_got.offset = (bfd_vma) -1;
if (!edir->has_bnd_reloc)
edir->has_bnd_reloc = eind->has_bnd_reloc;
+ if (!edir->has_got_reloc)
+ edir->has_got_reloc = eind->has_got_reloc;
+
+ if (!edir->has_non_got_reloc)
+ edir->has_non_got_reloc = eind->has_non_got_reloc;
+
if (eind->dyn_relocs != NULL)
{
if (edir->dyn_relocs != NULL)
unsigned int r_type;
unsigned long r_symndx;
struct elf_link_hash_entry *h;
+ struct elf_x86_64_link_hash_entry *eh;
Elf_Internal_Sym *isym;
const char *name;
bfd_boolean size_reloc;
rel, rel_end, h, r_symndx))
return FALSE;
+ eh = (struct elf_x86_64_link_hash_entry *) h;
switch (r_type)
{
case R_X86_64_TLSLD:
bfd_set_error (bfd_error_bad_value);
return FALSE;
}
+ if (eh != NULL)
+ eh->has_got_reloc = 1;
break;
case R_X86_64_GOTTPOFF:
if (h != NULL)
{
h->got.refcount += 1;
- old_tls_type = elf_x86_64_hash_entry (h)->tls_type;
+ old_tls_type = eh->tls_type;
}
else
{
if (old_tls_type != tls_type)
{
- if (h != NULL)
- elf_x86_64_hash_entry (h)->tls_type = tls_type;
+ if (eh != NULL)
+ eh->tls_type = tls_type;
else
elf_x86_64_local_got_tls_type (abfd) [r_symndx] = tls_type;
}
case R_X86_64_GOTPC32:
case R_X86_64_GOTPC64:
create_got:
+ if (eh != NULL)
+ eh->has_got_reloc = 1;
if (htab->elf.sgot == NULL)
{
if (htab->elf.dynobj == NULL)
if (h == NULL)
continue;
+ eh->has_got_reloc = 1;
h->needs_plt = 1;
h->plt.refcount += 1;
break;
case R_X86_64_PC64:
case R_X86_64_64:
pointer:
+ if (eh != NULL && (sec->flags & SEC_CODE) != 0)
+ eh->has_non_got_reloc = 1;
if (h != NULL && bfd_link_executable (info))
{
/* If this reloc is in a read-only section, we might
|| (!ABI_64_P (abfd)
&& (r_type == R_X86_64_32
|| r_type == R_X86_64_32S))))
- {
- struct elf_x86_64_link_hash_entry *eh
- = (struct elf_x86_64_link_hash_entry *) h;
- eh->func_pointer_refcount += 1;
- }
+ eh->func_pointer_refcount += 1;
}
}
/* If this is a global symbol, we count the number of
relocations we need for this symbol. */
if (h != NULL)
- {
- head = &((struct elf_x86_64_link_hash_entry *) h)->dyn_relocs;
- }
+ head = &eh->dyn_relocs;
else
{
/* Track dynamic relocs needed for local syms too.
return TRUE;
}
+/* Remove undefined weak symbol from the dynamic symbol table if it
+ is resolved to 0. */
+
+static bfd_boolean
+elf_x86_64_fixup_symbol (struct bfd_link_info *info,
+ struct elf_link_hash_entry *h)
+{
+ if (h->dynindx != -1
+ && UNDEFINED_WEAK_RESOLVED_TO_ZERO (info,
+ elf_x86_64_hash_entry (h)))
+ {
+ h->dynindx = -1;
+ _bfd_elf_strtab_delref (elf_hash_table (info)->dynstr,
+ h->dynstr_index);
+ }
+ return TRUE;
+}
+
/* Adjust a symbol defined by a dynamic object and referenced by a
regular object. The current definition is in some section of the
dynamic object, but we're not including those sections. We have to
struct elf_dyn_relocs *p;
const struct elf_backend_data *bed;
unsigned int plt_entry_size;
+ bfd_boolean resolved_to_zero;
if (h->root.type == bfd_link_hash_indirect)
return TRUE;
bed = get_elf_backend_data (info->output_bfd);
plt_entry_size = GET_PLT_ENTRY_SIZE (info->output_bfd);
+ resolved_to_zero = UNDEFINED_WEAK_RESOLVED_TO_ZERO (info, eh);
+
/* We can't use the GOT PLT if pointer equality is needed since
finish_dynamic_symbol won't clear symbol value and the dynamic
linker won't update the GOT slot. We will get into an infinite
/* Make sure this symbol is output as a dynamic symbol.
Undefined weak syms won't yet be marked as dynamic. */
if (h->dynindx == -1
- && !h->forced_local)
+ && !h->forced_local
+ && !resolved_to_zero)
{
if (! bfd_elf_link_record_dynamic_symbol (info, h))
return FALSE;
script. */
htab->elf.sgotplt->size += GOT_ENTRY_SIZE;
- /* We also need to make an entry in the .rela.plt
- section. */
- htab->elf.srelplt->size += bed->s->sizeof_rela;
- htab->elf.srelplt->reloc_count++;
+ /* There should be no PLT relocation against resolved
+ undefined weak symbol in executable. */
+ if (!resolved_to_zero)
+ {
+ /* We also need to make an entry in the .rela.plt
+ section. */
+ htab->elf.srelplt->size += bed->s->sizeof_rela;
+ htab->elf.srelplt->reloc_count++;
+ }
}
}
else
/* Make sure this symbol is output as a dynamic symbol.
Undefined weak syms won't yet be marked as dynamic. */
if (h->dynindx == -1
- && !h->forced_local)
+ && !h->forced_local
+ && !resolved_to_zero)
{
if (! bfd_elf_link_record_dynamic_symbol (info, h))
return FALSE;
}
dyn = htab->elf.dynamic_sections_created;
/* R_X86_64_TLSGD needs one dynamic relocation if local symbol
- and two if global.
- R_X86_64_GOTTPOFF needs one dynamic relocation. */
+ and two if global. R_X86_64_GOTTPOFF needs one dynamic
+ relocation. No dynamic relocation against resolved undefined
+ weak symbol in executable. */
if ((GOT_TLS_GD_P (tls_type) && h->dynindx == -1)
|| tls_type == GOT_TLS_IE)
htab->elf.srelgot->size += bed->s->sizeof_rela;
else if (GOT_TLS_GD_P (tls_type))
htab->elf.srelgot->size += 2 * bed->s->sizeof_rela;
else if (! GOT_TLS_GDESC_P (tls_type)
- && (ELF_ST_VISIBILITY (h->other) == STV_DEFAULT
+ && ((ELF_ST_VISIBILITY (h->other) == STV_DEFAULT
+ && !resolved_to_zero)
|| h->root.type != bfd_link_hash_undefweak)
&& (bfd_link_pic (info)
|| WILL_CALL_FINISH_DYNAMIC_SYMBOL (dyn, 0, h)))
}
/* Also discard relocs on undefined weak syms with non-default
- visibility. */
+ visibility or in PIE. */
if (eh->dyn_relocs != NULL)
{
if (h->root.type == bfd_link_hash_undefweak)
{
- if (ELF_ST_VISIBILITY (h->other) != STV_DEFAULT)
+ /* Undefined weak symbol is never bound locally in shared
+ library. */
+ if (ELF_ST_VISIBILITY (h->other) != STV_DEFAULT
+ || resolved_to_zero)
eh->dyn_relocs = NULL;
-
- /* Make sure undefined weak symbols are output as a dynamic
- symbol in PIEs. */
else if (h->dynindx == -1
&& ! h->forced_local
&& ! bfd_elf_link_record_dynamic_symbol (info, h))
dynamic. Keep dynamic relocations for run-time function
pointer initialization. */
- if ((!h->non_got_ref || eh->func_pointer_refcount > 0)
+ if ((!h->non_got_ref
+ || eh->func_pointer_refcount > 0
+ || (h->root.type == bfd_link_hash_undefweak
+ && !resolved_to_zero))
&& ((h->def_dynamic
&& !h->def_regular)
|| (htab->elf.dynamic_sections_created
Undefined weak syms won't yet be marked as dynamic. */
if (h->dynindx == -1
&& ! h->forced_local
+ && ! resolved_to_zero
&& ! bfd_elf_link_record_dynamic_symbol (info, h))
return FALSE;
abort ();
s->size = htab->dynamic_interpreter_size;
s->contents = (unsigned char *) htab->dynamic_interpreter;
+ htab->interp = s;
}
}
int tls_type;
asection *base_got, *resolved_plt;
bfd_vma st_size;
+ bfd_boolean resolved_to_zero;
r_type = ELF32_R_TYPE (rel->r_info);
if (r_type == (int) R_X86_64_GNU_VTINHERIT
}
}
+ resolved_to_zero = (eh != NULL
+ && UNDEFINED_WEAK_RESOLVED_TO_ZERO (info, eh));
+
/* When generating a shared object, the relocations handled here are
copied into the output file to be resolved at run time. */
switch (r_type)
case R_X86_64_PC32:
case R_X86_64_PC32_BND:
/* Don't complain about -fPIC if the symbol is undefined when
- building executable. */
- if (bfd_link_pic (info)
- && (input_section->flags & SEC_ALLOC) != 0
+ building executable unless it is unresolved weak symbol. */
+ if ((input_section->flags & SEC_ALLOC) != 0
&& (input_section->flags & SEC_READONLY) != 0
&& h != NULL
- && !(bfd_link_executable (info)
- && h->root.type == bfd_link_hash_undefined))
+ && ((bfd_link_executable (info)
+ && h->root.type == bfd_link_hash_undefweak
+ && !resolved_to_zero)
+ || (bfd_link_pic (info)
+ && !(bfd_link_pie (info)
+ && h->root.type == bfd_link_hash_undefined))))
{
bfd_boolean fail = FALSE;
bfd_boolean branch
defined locally or for a branch. */
fail = !h->def_regular && !branch;
}
- else if (!(bfd_link_executable (info)
+ else if (!(bfd_link_pie (info)
&& (h->needs_copy || eh->needs_copy)))
{
/* Symbol doesn't need copy reloc and isn't referenced
/* 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. */
+ relocations. Don't generate dynamic relocations against
+ resolved undefined weak symbols in PIE. */
if ((bfd_link_pic (info)
- && !(bfd_link_executable (info)
+ && !(bfd_link_pie (info)
&& h != NULL
&& (h->needs_copy
|| eh->needs_copy
|| h->root.type == bfd_link_hash_undefined)
&& IS_X86_64_PCREL_TYPE (r_type))
&& (h == NULL
- || ELF_ST_VISIBILITY (h->other) == STV_DEFAULT
- || h->root.type != bfd_link_hash_undefweak)
+ || ((ELF_ST_VISIBILITY (h->other) == STV_DEFAULT
+ && !resolved_to_zero)
+ || h->root.type != bfd_link_hash_undefweak))
&& ((! IS_X86_64_PCREL_TYPE (r_type)
&& r_type != R_X86_64_SIZE32
&& r_type != R_X86_64_SIZE64)
&& !bfd_link_pic (info)
&& h != NULL
&& h->dynindx != -1
- && (!h->non_got_ref || eh->func_pointer_refcount > 0)
+ && (!h->non_got_ref
+ || eh->func_pointer_refcount > 0
+ || (h->root.type == bfd_link_hash_undefweak
+ && !resolved_to_zero))
&& ((h->def_dynamic
&& !h->def_regular)
|| h->root.type == bfd_link_hash_undefweak
|| ! SYMBOLIC_BIND (info, h)
|| ! h->def_regular))
{
+ if ((r_type != R_X86_64_PC64 && r_type != R_X86_64_64)
+ && bfd_link_executable (info)
+ && h->root.type == bfd_link_hash_undefweak
+ && !resolved_to_zero)
+ return elf_x86_64_need_pic (input_bfd, h, howto);
outrel.r_info = htab->r_info (h->dynindx, r_type);
outrel.r_addend = rel->r_addend;
}
elf_x86_64_finish_dynamic_symbol (bfd *output_bfd,
struct bfd_link_info *info,
struct elf_link_hash_entry *h,
- Elf_Internal_Sym *sym ATTRIBUTE_UNUSED)
+ Elf_Internal_Sym *sym)
{
struct elf_x86_64_link_hash_table *htab;
const struct elf_x86_64_backend_data *abed;
bfd_boolean use_plt_bnd;
struct elf_x86_64_link_hash_entry *eh;
+ bfd_boolean local_undefweak;
htab = elf_x86_64_hash_table (info);
if (htab == NULL)
eh = (struct elf_x86_64_link_hash_entry *) h;
+ /* We keep PLT/GOT entries without dynamic PLT/GOT relocations for
+ resolved undefined weak symbols in executable so that their
+ references have value 0 at run-time. */
+ local_undefweak = UNDEFINED_WEAK_RESOLVED_TO_ZERO (info, eh);
+
if (h->plt.offset != (bfd_vma) -1)
{
bfd_vma plt_index;
/* This symbol has an entry in the procedure linkage table. Set
it up. */
if ((h->dynindx == -1
+ && !local_undefweak
&& !((h->forced_local || bfd_link_executable (info))
&& h->def_regular
&& h->type == STT_GNU_IFUNC))
resolved_plt->contents + plt_offset + plt_got_offset);
/* Fill in the entry in the global offset table, initially this
- points to the second part of the PLT entry. */
- bfd_put_64 (output_bfd, (plt->output_section->vma
- + plt->output_offset
- + h->plt.offset + abed->plt_lazy_offset),
- gotplt->contents + got_offset);
-
- /* Fill in the entry in the .rela.plt section. */
- rela.r_offset = (gotplt->output_section->vma
- + gotplt->output_offset
- + got_offset);
- if (h->dynindx == -1
- || ((bfd_link_executable (info)
- || ELF_ST_VISIBILITY (h->other) != STV_DEFAULT)
- && h->def_regular
- && h->type == STT_GNU_IFUNC))
+ points to the second part of the PLT entry. Leave the entry
+ as zero for undefined weak symbol in PIE. No PLT relocation
+ against undefined weak symbol in PIE. */
+ if (!local_undefweak)
{
- /* If an STT_GNU_IFUNC symbol is locally defined, generate
- R_X86_64_IRELATIVE instead of R_X86_64_JUMP_SLOT. */
- rela.r_info = htab->r_info (0, R_X86_64_IRELATIVE);
- rela.r_addend = (h->root.u.def.value
- + h->root.u.def.section->output_section->vma
- + h->root.u.def.section->output_offset);
- /* R_X86_64_IRELATIVE comes last. */
- plt_index = htab->next_irelative_index--;
- }
- else
- {
- rela.r_info = htab->r_info (h->dynindx, R_X86_64_JUMP_SLOT);
- rela.r_addend = 0;
- plt_index = htab->next_jump_slot_index++;
- }
+ bfd_put_64 (output_bfd, (plt->output_section->vma
+ + plt->output_offset
+ + h->plt.offset
+ + abed->plt_lazy_offset),
+ gotplt->contents + got_offset);
+
+ /* Fill in the entry in the .rela.plt section. */
+ rela.r_offset = (gotplt->output_section->vma
+ + gotplt->output_offset
+ + got_offset);
+ if (h->dynindx == -1
+ || ((bfd_link_executable (info)
+ || ELF_ST_VISIBILITY (h->other) != STV_DEFAULT)
+ && h->def_regular
+ && h->type == STT_GNU_IFUNC))
+ {
+ /* If an STT_GNU_IFUNC symbol is locally defined, generate
+ R_X86_64_IRELATIVE instead of R_X86_64_JUMP_SLOT. */
+ rela.r_info = htab->r_info (0, R_X86_64_IRELATIVE);
+ rela.r_addend = (h->root.u.def.value
+ + h->root.u.def.section->output_section->vma
+ + h->root.u.def.section->output_offset);
+ /* R_X86_64_IRELATIVE comes last. */
+ plt_index = htab->next_irelative_index--;
+ }
+ else
+ {
+ rela.r_info = htab->r_info (h->dynindx, R_X86_64_JUMP_SLOT);
+ rela.r_addend = 0;
+ plt_index = htab->next_jump_slot_index++;
+ }
- /* Don't fill PLT entry for static executables. */
- if (plt == htab->elf.splt)
- {
- bfd_vma plt0_offset = h->plt.offset + plt_plt_insn_end;
-
- /* Put relocation index. */
- bfd_put_32 (output_bfd, plt_index,
- plt->contents + h->plt.offset + abed->plt_reloc_offset);
-
- /* Put offset for jmp .PLT0 and check for overflow. We don't
- check relocation index for overflow since branch displacement
- will overflow first. */
- if (plt0_offset > 0x80000000)
- info->callbacks->einfo (_("%F%B: branch displacement overflow in PLT entry for `%s'\n"),
- output_bfd, h->root.root.string);
- bfd_put_32 (output_bfd, - plt0_offset,
- plt->contents + h->plt.offset + plt_plt_offset);
- }
+ /* Don't fill PLT entry for static executables. */
+ if (plt == htab->elf.splt)
+ {
+ bfd_vma plt0_offset = h->plt.offset + plt_plt_insn_end;
+
+ /* Put relocation index. */
+ bfd_put_32 (output_bfd, plt_index,
+ (plt->contents + h->plt.offset
+ + abed->plt_reloc_offset));
+
+ /* Put offset for jmp .PLT0 and check for overflow. We don't
+ check relocation index for overflow since branch displacement
+ will overflow first. */
+ if (plt0_offset > 0x80000000)
+ info->callbacks->einfo (_("%F%B: branch displacement overflow in PLT entry for `%s'\n"),
+ output_bfd, h->root.root.string);
+ bfd_put_32 (output_bfd, - plt0_offset,
+ plt->contents + h->plt.offset + plt_plt_offset);
+ }
- bed = get_elf_backend_data (output_bfd);
- loc = relplt->contents + plt_index * bed->s->sizeof_rela;
- bed->s->swap_reloca_out (output_bfd, &rela, loc);
+ bed = get_elf_backend_data (output_bfd);
+ loc = relplt->contents + plt_index * bed->s->sizeof_rela;
+ bed->s->swap_reloca_out (output_bfd, &rela, loc);
+ }
}
else if (eh->plt_got.offset != (bfd_vma) -1)
{
plt->contents + plt_offset + plt_got_offset);
}
- if (!h->def_regular
+ if (!local_undefweak
+ && !h->def_regular
&& (h->plt.offset != (bfd_vma) -1
|| eh->plt_got.offset != (bfd_vma) -1))
{
sym->st_value = 0;
}
+ /* Don't generate dynamic GOT relocation against undefined weak
+ symbol in executable. */
if (h->got.offset != (bfd_vma) -1
&& ! GOT_TLS_GD_ANY_P (elf_x86_64_hash_entry (h)->tls_type)
- && elf_x86_64_hash_entry (h)->tls_type != GOT_TLS_IE)
+ && elf_x86_64_hash_entry (h)->tls_type != GOT_TLS_IE
+ && !local_undefweak)
{
Elf_Internal_Rela rela;
info, h, NULL);
}
+/* Finish up undefined weak symbol handling in PIE. Fill its PLT entry
+ here since undefined weak symbol may not be dynamic and may not be
+ called for elf_x86_64_finish_dynamic_symbol. */
+
+static bfd_boolean
+elf_x86_64_pie_finish_undefweak_symbol (struct bfd_hash_entry *bh,
+ void *inf)
+{
+ struct elf_link_hash_entry *h = (struct elf_link_hash_entry *) bh;
+ struct bfd_link_info *info = (struct bfd_link_info *) inf;
+
+ if (h->root.type != bfd_link_hash_undefweak
+ || h->dynindx != -1)
+ return TRUE;
+
+ return elf_x86_64_finish_dynamic_symbol (info->output_bfd,
+ info, h, NULL);
+}
+
/* Used to decide how to sort relocs in an optimal manner for the
dynamic linker, before writing them out. */
elf_x86_64_finish_local_dynamic_symbol,
info);
+ /* Fill PLT entries for undefined weak symbols in PIE. */
+ if (bfd_link_pie (info))
+ bfd_hash_traverse (&info->hash->table,
+ elf_x86_64_pie_finish_undefweak_symbol,
+ info);
+
return TRUE;
}
elf_x86_64_hash_symbol
#define elf_backend_omit_section_dynsym \
((bfd_boolean (*) (bfd *, struct bfd_link_info *, asection *)) bfd_true)
+#define elf_backend_fixup_symbol \
+ elf_x86_64_fixup_symbol
#include "elf64-target.h"
projects / deliverable / binutils-gdb.git / blobdiff