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PowerPC64, support medium model access to common symbols

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Some versions of clang apparently generate non-PIC on powerpc64le to
access common symbols.  Since a common symbol and a strong definition
with the same name should resolve to the strong definition we have the
possibility of non-PIC attempting to access shared library variables.
This is really a clanger since powerpc64le is supposed to be PIC by
default, but let's see if ld can cope by generating .dynbss copies.

	* elf64-ppc.c (must_be_dyn_reloc): Return 0 for TOC16 relocs.
	(ppc64_elf_check_relocs): Support dynamic/copy relocs for TOC16.
	(ppc64_elf_adjust_dynamic_symbol): Don't keep dynamic reloc when
	needs_copy even if all relocs are in rw sections.
	(dec_dynrel_count): Handle TOC16 relocs.
	(ppc64_elf_relocate_section): Support dynamic relocs for TOC16.
	(ppc64_elf_finish_dynamic_symbol): Adjust to handle needs_copy
	semantic change.
This commit is contained in:
Alan Modra 2019-09-18 10:27:23 +09:30
parent a3d181d2e7
commit 1bdd8facfb
2 changed files with 48 additions and 7 deletions
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11
bfd/ChangeLog
View File

@ -1,3 +1,14 @@
2019-09-18 Alan Modra <amodra@gmail.com>
* elf64-ppc.c (must_be_dyn_reloc): Return 0 for TOC16 relocs.
(ppc64_elf_check_relocs): Support dynamic/copy relocs for TOC16.
(ppc64_elf_adjust_dynamic_symbol): Don't keep dynamic reloc when
needs_copy even if all relocs are in rw sections.
(dec_dynrel_count): Handle TOC16 relocs.
(ppc64_elf_relocate_section): Support dynamic relocs for TOC16.
(ppc64_elf_finish_dynamic_symbol): Adjust to handle needs_copy
semantic change.
2019-09-16 Phil Blundell <pb@pbcl.net>
* version.m4: Set version to 2.33.50.

44
bfd/elf64-ppc.c
View File

@ -2745,6 +2745,12 @@ must_be_dyn_reloc (struct bfd_link_info *info,
case R_PPC64_REL32:
case R_PPC64_REL64:
case R_PPC64_REL30:
case R_PPC64_TOC16:
case R_PPC64_TOC16_DS:
case R_PPC64_TOC16_LO:
case R_PPC64_TOC16_HI:
case R_PPC64_TOC16_HA:
case R_PPC64_TOC16_LO_DS:
return 0;
case R_PPC64_TPREL16:
@ -4830,6 +4836,16 @@ ppc64_elf_check_relocs (bfd *abfd, struct bfd_link_info *info,
case R_PPC64_TOC16_HA:
case R_PPC64_TOC16_LO_DS:
sec->has_toc_reloc = 1;
if (h != NULL && !bfd_link_pic (info))
{
/* We may need a copy reloc. */
h->non_got_ref = 1;
/* Strongly prefer a copy reloc over a dynamic reloc.
glibc ld.so as of 2019-08 will error out if one of
these relocations is emitted. */
h->needs_copy = 1;
goto dodyn;
}
break;
/* Marker reloc. */
@ -6425,7 +6441,9 @@ ppc64_elf_adjust_dynamic_symbol (struct bfd_link_info *info,
/* If we don'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 && !alias_readonly_dynrelocs (h))
|| (ELIMINATE_COPY_RELOCS
&& !h->needs_copy
&& !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
@ -6813,6 +6831,16 @@ dec_dynrel_count (bfd_vma r_info,
default:
return TRUE;
case R_PPC64_TOC16:
case R_PPC64_TOC16_DS:
case R_PPC64_TOC16_LO:
case R_PPC64_TOC16_HI:
case R_PPC64_TOC16_HA:
case R_PPC64_TOC16_LO_DS:
if (h == NULL)
return TRUE;
break;
case R_PPC64_TPREL16:
case R_PPC64_TPREL16_LO:
case R_PPC64_TPREL16_HI:
@ -15801,6 +15829,8 @@ ppc64_elf_relocate_section (bfd *output_bfd,
case R_PPC64_TOC16_LO_DS:
case R_PPC64_TOC16_HA:
addend -= TOCstart + htab->sec_info[input_section->id].toc_off;
if (h != NULL)
goto dodyn;
break;
/* Relocate against the beginning of the section. */
@ -16734,18 +16764,18 @@ ppc64_elf_finish_dynamic_symbol (bfd *output_bfd,
break;
}
if (h->needs_copy)
if (h->needs_copy
&& (h->root.type == bfd_link_hash_defined
|| h->root.type == bfd_link_hash_defweak)
&& (h->root.u.def.section == htab->elf.sdynbss
|| h->root.u.def.section == htab->elf.sdynrelro))
{
/* This symbol needs a copy reloc. Set it up. */
Elf_Internal_Rela rela;
asection *srel;
bfd_byte *loc;
if (h->dynindx == -1
|| (h->root.type != bfd_link_hash_defined
&& h->root.type != bfd_link_hash_defweak)
|| htab->elf.srelbss == NULL
|| htab->elf.sreldynrelro == NULL)
if (h->dynindx == -1)
abort ();
rela.r_offset = (h->root.u.def.value