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Re: [Bug ld/11088] Internal Error in ppc64_elf_gc_sweep_hook
- From: Alan Modra <amodra at bigpond dot net dot au>
- To: Nick Clifton <nickc at redhat dot com>, binutils at sourceware dot org
- Date: Thu, 17 Dec 2009 16:17:53 +1030
- Subject: Re: [Bug ld/11088] Internal Error in ppc64_elf_gc_sweep_hook
- References: <20091214113104.11088.nickc@redhat.com> <20091214234056.31975.qmail@sourceware.org> <4B289DA6.7060100@redhat.com> <20091217000820.GE1964@bubble.grove.modra.org>
I've put this patch under PR11088 because the fixes to gc_sweep_hook
here are identical to those for PowerPC64, and the rest of the patch
fixes related plt reference counting, in particular of R_PPC_PLTREL24
relocs. These problems might show up in PIEs.
include/elf/
* ppc.h (R_PPC_RELAX32, R_PPC_RELAX32PC, R_PPC_RELAX32_PLT,
R_PPC_RELAX32PC_PLT): Delete.
(R_PPC_RELAX, R_PPC_RELAX_PLT, R_PPC_RELAX_PLTREL24): Define.
bfd/
PR ld/11088
* elf32-ppc.c (update_plt_info): Clear sec here when addend is
less than 32768..
(ppc_elf_check_relocs): ..rather than doing so here. Ignore new
relax relocs.
(ppc_elf_gc_sweep_hook): Don't segfault when symbol hiding has
removed plt_entry records.
(ppc_elf_tls_setup): Handle PIE calls to __tls_get_addr correctly.
(ppc_elf_tls_optimize): Likewise. Also dec __tls_get_addr refcount
when optimizing code using new tlsgd and tlsld marker relocs.
(ppc_elf_relax_section): Differentiate relaxed PLTREL24 relocs
from ADDR24 relocs using plt or glink. Don't clear the addend
for R_PPC_RELAX_PLTREL24.
(ppc_elf_relocate_section): Correctly handle addends on relaxed
PLTREL24 relocs.
Index: include/elf/ppc.h
===================================================================
RCS file: /cvs/src/src/include/elf/ppc.h,v
retrieving revision 1.26
diff -u -p -r1.26 ppc.h
--- include/elf/ppc.h 21 Sep 2009 11:51:01 -0000 1.26
+++ include/elf/ppc.h 11 Dec 2009 08:12:30 -0000
@@ -73,10 +73,9 @@ START_RELOC_NUMBERS (elf_ppc_reloc_type)
#ifndef RELOC_MACROS_GEN_FUNC
/* Fake relocations for branch stubs, only used internally by ld. */
- RELOC_NUMBER (R_PPC_RELAX32, 48)
- RELOC_NUMBER (R_PPC_RELAX32PC, 49)
- RELOC_NUMBER (R_PPC_RELAX32_PLT, 50)
- RELOC_NUMBER (R_PPC_RELAX32PC_PLT, 51)
+ RELOC_NUMBER (R_PPC_RELAX, 48)
+ RELOC_NUMBER (R_PPC_RELAX_PLT, 49)
+ RELOC_NUMBER (R_PPC_RELAX_PLTREL24, 50)
#endif
/* Relocs added to support TLS. */
Index: bfd/elf32-ppc.c
===================================================================
RCS file: /cvs/src/src/bfd/elf32-ppc.c,v
retrieving revision 1.272
diff -u -p -r1.272 elf32-ppc.c
--- bfd/elf32-ppc.c 11 Dec 2009 13:42:02 -0000 1.272
+++ bfd/elf32-ppc.c 17 Dec 2009 00:14:04 -0000
@@ -3323,6 +3323,8 @@ update_plt_info (bfd *abfd, struct plt_e
{
struct plt_entry *ent;
+ if (addend < 32768)
+ sec = NULL;
for (ent = *plist; ent != NULL; ent = ent->next)
if (ent->sec == sec && ent->addend == addend)
break;
@@ -3508,8 +3510,7 @@ ppc_elf_check_relocs (bfd *abfd,
if (info->shared)
addend = rel->r_addend;
}
- if (!update_plt_info (abfd, ifunc,
- addend < 32768 ? NULL : got2, addend))
+ if (!update_plt_info (abfd, ifunc, got2, addend))
return FALSE;
}
}
@@ -3748,8 +3749,7 @@ ppc_elf_check_relocs (bfd *abfd,
addend = rel->r_addend;
}
h->needs_plt = 1;
- if (!update_plt_info (abfd, &h->plt.plist,
- addend < 32768 ? NULL : got2, addend))
+ if (!update_plt_info (abfd, &h->plt.plist, got2, addend))
return FALSE;
}
break;
@@ -3780,10 +3780,9 @@ ppc_elf_check_relocs (bfd *abfd,
case R_PPC_EMB_MRKREF:
case R_PPC_NONE:
case R_PPC_max:
- case R_PPC_RELAX32:
- case R_PPC_RELAX32PC:
- case R_PPC_RELAX32_PLT:
- case R_PPC_RELAX32PC_PLT:
+ case R_PPC_RELAX:
+ case R_PPC_RELAX_PLT:
+ case R_PPC_RELAX_PLTREL24:
break;
/* These should only appear in dynamic objects. */
@@ -4486,7 +4485,7 @@ ppc_elf_gc_sweep_hook (bfd *abfd,
struct plt_entry *ent;
ent = find_plt_ent (&h->plt.plist, NULL, 0);
- if (ent->plt.refcount > 0)
+ if (ent != NULL && ent->plt.refcount > 0)
ent->plt.refcount -= 1;
}
}
@@ -4534,7 +4533,7 @@ ppc_elf_gc_sweep_hook (bfd *abfd,
if (r_type == R_PPC_PLTREL24 && info->shared)
addend = rel->r_addend;
ent = find_plt_ent (&h->plt.plist, got2, addend);
- if (ent->plt.refcount > 0)
+ if (ent != NULL && ent->plt.refcount > 0)
ent->plt.refcount -= 1;
}
break;
@@ -4582,9 +4581,10 @@ ppc_elf_tls_setup (bfd *obfd,
&& tga->root.type == bfd_link_hash_undefweak)))
{
struct plt_entry *ent;
- ent = find_plt_ent (&tga->plt.plist, NULL, 0);
- if (ent != NULL
- && ent->plt.refcount > 0)
+ for (ent = tga->plt.plist; ent != NULL; ent = ent->next)
+ if (ent->plt.refcount > 0)
+ break;
+ if (ent != NULL)
{
tga->root.type = bfd_link_hash_indirect;
tga->root.u.i.link = &opt->root;
@@ -4669,6 +4669,7 @@ ppc_elf_tls_optimize (bfd *obfd ATTRIBUT
{
Elf_Internal_Sym *locsyms = NULL;
Elf_Internal_Shdr *symtab_hdr = &elf_symtab_hdr (ibfd);
+ asection *got2 = bfd_get_section_by_name (ibfd, ".got2");
for (sec = ibfd->sections; sec != NULL; sec = sec->next)
if (sec->has_tls_reloc && !bfd_is_abs_section (sec->output_section))
@@ -4762,6 +4763,13 @@ ppc_elf_tls_optimize (bfd *obfd ATTRIBUT
else
continue;
+ case R_PPC_TLSGD:
+ case R_PPC_TLSLD:
+ expecting_tls_get_addr = 2;
+ tls_set = 0;
+ tls_clear = 0;
+ break;
+
default:
continue;
}
@@ -4769,7 +4777,8 @@ ppc_elf_tls_optimize (bfd *obfd ATTRIBUT
if (pass == 0)
{
if (!expecting_tls_get_addr
- || !sec->has_tls_get_addr_call)
+ || (expecting_tls_get_addr == 1
+ && !sec->has_tls_get_addr_call))
continue;
if (rel + 1 < relend
@@ -4785,6 +4794,23 @@ ppc_elf_tls_optimize (bfd *obfd ATTRIBUT
break;
}
+ if (expecting_tls_get_addr)
+ {
+ struct plt_entry *ent;
+ bfd_vma addend = 0;
+
+ if (info->shared
+ && ELF32_R_TYPE (rel[1].r_info) == R_PPC_PLTREL24)
+ addend = rel[1].r_addend;
+ ent = find_plt_ent (&htab->tls_get_addr->plt.plist,
+ got2, addend);
+ if (ent != NULL && ent->plt.refcount > 0)
+ ent->plt.refcount -= 1;
+
+ if (expecting_tls_get_addr == 2)
+ continue;
+ }
+
if (h != NULL)
{
tls_mask = &ppc_elf_hash_entry (h)->tls_mask;
@@ -4829,16 +4855,6 @@ ppc_elf_tls_optimize (bfd *obfd ATTRIBUT
*got_count -= 1;
}
- if (expecting_tls_get_addr)
- {
- struct plt_entry *ent;
-
- ent = find_plt_ent (&htab->tls_get_addr->plt.plist,
- NULL, 0);
- if (ent != NULL && ent->plt.refcount > 0)
- ent->plt.refcount -= 1;
- }
-
*tls_mask |= tls_set;
*tls_mask &= ~tls_clear;
}
@@ -6239,28 +6255,28 @@ ppc_elf_relax_section (bfd *abfd,
{
size = 4 * ARRAY_SIZE (shared_stub_entry);
insn_offset = 12;
- stub_rtype = R_PPC_RELAX32PC;
}
else
{
size = 4 * ARRAY_SIZE (stub_entry);
insn_offset = 0;
- stub_rtype = R_PPC_RELAX32;
}
-
- if (R_PPC_RELAX32_PLT - R_PPC_RELAX32
- != R_PPC_RELAX32PC_PLT - R_PPC_RELAX32PC)
- abort ();
+ stub_rtype = R_PPC_RELAX;
if (tsec == htab->plt
|| tsec == htab->glink)
- stub_rtype += R_PPC_RELAX32_PLT - R_PPC_RELAX32;
+ {
+ stub_rtype = R_PPC_RELAX_PLT;
+ if (r_type == R_PPC_PLTREL24)
+ stub_rtype = R_PPC_RELAX_PLTREL24;
+ }
/* Hijack the old relocation. Since we need two
relocations for this use a "composite" reloc. */
irel->r_info = ELF32_R_INFO (ELF32_R_SYM (irel->r_info),
stub_rtype);
irel->r_offset = trampoff + insn_offset;
- if (r_type == R_PPC_PLTREL24)
+ if (r_type == R_PPC_PLTREL24
+ && stub_rtype != R_PPC_RELAX_PLTREL24)
irel->r_addend = 0;
/* Record the fixup so we don't do it again this section. */
@@ -6430,7 +6446,7 @@ ppc_elf_relax_section (bfd *abfd,
{
/* Convert the internal relax relocs to external form. */
for (irel = internal_relocs; irel < irelend; irel++)
- if (ELF32_R_TYPE (irel->r_info) == R_PPC_RELAX32)
+ if (ELF32_R_TYPE (irel->r_info) == R_PPC_RELAX)
{
unsigned long r_symndx = ELF32_R_SYM (irel->r_info);
@@ -7669,12 +7685,20 @@ ppc_elf_relocate_section (bfd *output_bf
}
break;
- case R_PPC_RELAX32PC_PLT:
- case R_PPC_RELAX32_PLT:
+ case R_PPC_RELAX_PLT:
+ case R_PPC_RELAX_PLTREL24:
if (h != NULL)
{
- struct plt_entry *ent = find_plt_ent (&h->plt.plist, got2,
- info->shared ? addend : 0);
+ struct plt_entry *ent;
+ bfd_vma got2_addend = 0;
+
+ if (r_type == R_PPC_RELAX_PLTREL24)
+ {
+ if (info->shared)
+ got2_addend = addend;
+ addend = 0;
+ }
+ ent = find_plt_ent (&h->plt.plist, got2, got2_addend);
if (htab->plt_type == PLT_NEW)
relocation = (htab->glink->output_section->vma
+ htab->glink->output_offset
@@ -7684,18 +7708,14 @@ ppc_elf_relocate_section (bfd *output_bf
+ htab->plt->output_offset
+ ent->plt.offset);
}
- if (r_type == R_PPC_RELAX32_PLT)
- goto relax32;
/* Fall thru */
- case R_PPC_RELAX32PC:
- relocation -= (input_section->output_section->vma
- + input_section->output_offset
- + rel->r_offset - 4);
- /* Fall thru */
+ case R_PPC_RELAX:
+ if (info->shared)
+ relocation -= (input_section->output_section->vma
+ + input_section->output_offset
+ + rel->r_offset - 4);
- case R_PPC_RELAX32:
- relax32:
{
unsigned long t0;
unsigned long t1;
--
Alan Modra
Australia Development Lab, IBM