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PowerPC64, Don't copy weak symbol dyn_relocs to weakdef.

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At the cost of an extra field in the symbol table hash entries, this
simplification to the relocate_section dynamic reloc test should help
maintainability.

	* elf64-ppc.c (struct ppc_link_hash_entry): Add weakref.
	(ppc64_elf_copy_indirect_symbol): Set weakref.  Don't merge
	dyn_relocs for weakdefs.
	(alias_readonly_dynrelocs): New function.
	(ppc64_elf_adjust_dynamic_symbol): Use alias_readonly_dynrelocs.
	(ppc64_elf_relocate_section): Simplify condition under which
	dyn_relocs are emitted.
This commit is contained in:
Alan Modra 2016-08-19 11:06:53 +09:30
parent 8a2058b5e3
commit d311bc8bf8
2 changed files with 77 additions and 31 deletions
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10
bfd/ChangeLog
View file

@ -1,3 +1,13 @@
2016-08-19 Alan Modra <amodra@gmail.com>
* elf64-ppc.c (struct ppc_link_hash_entry): Add weakref.
(ppc64_elf_copy_indirect_symbol): Set weakref. Don't merge
dyn_relocs for weakdefs.
(alias_readonly_dynrelocs): New function.
(ppc64_elf_adjust_dynamic_symbol): Use alias_readonly_dynrelocs.
(ppc64_elf_relocate_section): Simplify condition under which
dyn_relocs are emitted.
2016-08-19 Alan Modra <amodra@gmail.com>
PR 20472

98
bfd/elf64-ppc.c
View file

@ -3950,6 +3950,9 @@ struct ppc_link_hash_entry
/* Track dynamic relocs copied for this symbol. */
struct elf_dyn_relocs *dyn_relocs;
/* Chain of aliases referring to a weakdef. */
struct ppc_link_hash_entry *weakref;
/* Link between function code and descriptor symbols. */
struct ppc_link_hash_entry *oh;
@ -4738,6 +4741,45 @@ ppc64_elf_copy_indirect_symbol (struct bfd_link_info *info,
edir->elf.needs_plt |= eind->elf.needs_plt;
edir->elf.pointer_equality_needed |= eind->elf.pointer_equality_needed;
/* If we were called to copy over info for a weak sym, don't copy
dyn_relocs, plt/got info, or dynindx. We used to copy dyn_relocs
in order to simplify readonly_dynrelocs and save a field in the
symbol hash entry, but that means dyn_relocs can't be used in any
tests about a specific symbol, or affect other symbol flags which
are then tested.
Chain weakdefs so we can get from the weakdef back to an alias.
The list is circular so that we don't need to use u.weakdef as
well as this list to look at all aliases. */
if (eind->elf.root.type != bfd_link_hash_indirect)
{
struct ppc_link_hash_entry *cur, *add, *next;
add = eind;
do
{
cur = edir->weakref;
if (cur != NULL)
{
do
{
/* We can be called twice for the same symbols.
Don't make multiple loops. */
if (cur == add)
return;
cur = cur->weakref;
} while (cur != edir);
}
next = add->weakref;
if (cur != add)
{
add->weakref = edir->weakref != NULL ? edir->weakref : edir;
edir->weakref = add;
}
add = next;
} while (add != NULL && add != eind);
return;
}
/* Copy over any dynamic relocs we may have on the indirect sym. */
if (eind->dyn_relocs != NULL)
{
@ -4770,16 +4812,6 @@ ppc64_elf_copy_indirect_symbol (struct bfd_link_info *info,
eind->dyn_relocs = NULL;
}
/* If we were called to copy over info for a weak sym, that's all.
You might think dyn_relocs need not be copied over; After all,
both syms will be dynamic or both non-dynamic so we're just
moving reloc accounting around. However, ELIMINATE_COPY_RELOCS
code in ppc64_elf_adjust_dynamic_symbol needs to check for
dyn_relocs in read-only sections, and it does so on what is the
DIR sym here. */
if (eind->elf.root.type != bfd_link_hash_indirect)
return;
/* Copy over got entries that we may have already seen to the
symbol which just became indirect. */
if (eind->elf.got.glist != NULL)
@ -7122,6 +7154,24 @@ readonly_dynrelocs (struct elf_link_hash_entry *h)
return FALSE;
}
/* Return true if we have dynamic relocs against H or any of its weak
aliases, that apply to read-only sections. */
static bfd_boolean
alias_readonly_dynrelocs (struct elf_link_hash_entry *h)
{
struct ppc_link_hash_entry *eh;
eh = (struct ppc_link_hash_entry *) h;
do
{
if (readonly_dynrelocs (&eh->elf))
return TRUE;
eh = eh->weakref;
} while (eh != NULL && &eh->elf != h);
return FALSE;
}
/* Return true if a global entry stub will be created for H. Valid
for ELFv2 before plt entries have been allocated. */
@ -7192,7 +7242,7 @@ ppc64_elf_adjust_dynamic_symbol (struct bfd_link_info *info,
few more instructions, and pointer_equality_needed causes
extra work in ld.so when resolving these symbols. */
if (global_entry_stub (h)
&& !readonly_dynrelocs (h))
&& !alias_readonly_dynrelocs (h))
{
h->pointer_equality_needed = 0;
/* After adjust_dynamic_symbol, non_got_ref set in
@ -7242,7 +7292,7 @@ ppc64_elf_adjust_dynamic_symbol (struct bfd_link_info *info,
/* If we didn't find any dynamic relocs in read-only sections, then
we'll be keeping the dynamic relocs and avoiding the copy reloc. */
|| (ELIMINATE_COPY_RELOCS && !readonly_dynrelocs (h))
|| (ELIMINATE_COPY_RELOCS && !alias_readonly_dynrelocs (h))
/* Protected variables do not work with .dynbss. The copy in
.dynbss won't be used by the shared library with the protected
@ -14695,25 +14745,11 @@ ppc64_elf_relocate_section (bfd *output_bfd,
if (NO_OPD_RELOCS && is_opd)
break;
if (bfd_link_pic (info)
? ((h == NULL
|| ELF_ST_VISIBILITY (h->elf.other) == STV_DEFAULT
|| h->elf.root.type != bfd_link_hash_undefweak)
&& (must_be_dyn_reloc (info, r_type)
|| !SYMBOL_CALLS_LOCAL (info, &h->elf)))
: (h == NULL
? ELF_ST_TYPE (sym->st_info) == STT_GNU_IFUNC
: (h->elf.type == STT_GNU_IFUNC
? (abiversion (output_bfd) >= 2
? !(h->elf.pointer_equality_needed
&& !h->elf.def_regular
&& h->elf.root.type == bfd_link_hash_defined
&& h->elf.root.u.def.section == htab->glink)
: !h->elf.needs_copy)
: (ELIMINATE_COPY_RELOCS
&& !(h->elf.non_got_ref
|| h->elf.def_regular
|| h->elf.dynindx == -1)))))
if (h != NULL
? h->dyn_relocs != NULL
: (bfd_link_pic (info)
? must_be_dyn_reloc (info, r_type)
: ELF_ST_TYPE (sym->st_info) == STT_GNU_IFUNC))
{
bfd_boolean skip, relocate;
asection *sreloc;