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Re: Powerpc disassembly and gdb breakpoints
On Wed, Jul 02, 2008 at 09:43:14AM +0930, Alan Modra wrote:
> Sigh. Yes indeed. I forgot that -msecure-plt can require more than
> one glink stub per plt entry when -fPIC and -shared/-pie.
"Fixed" like so.
* elf32-ppc.c (is_pic_glink_stub): New function.
(ppc_elf_get_synthetic_symtab): Don't generate symbols when
multiple shared/pie stubs per plt entry.
Index: bfd/elf32-ppc.c
===================================================================
RCS file: /cvs/src/src/bfd/elf32-ppc.c,v
retrieving revision 1.239
diff -u -p -r1.239 elf32-ppc.c
--- bfd/elf32-ppc.c 30 Jun 2008 20:51:58 -0000 1.239
+++ bfd/elf32-ppc.c 2 Jul 2008 09:25:21 -0000
@@ -2292,6 +2292,29 @@ ppc_elf_final_write_processing (bfd *abf
}
static bfd_boolean
+is_pic_glink_stub (bfd *abfd, asection *glink, bfd_vma off)
+{
+ bfd_byte buf[16];
+ unsigned int insn;
+
+ if (!bfd_get_section_contents (abfd, glink, buf, off, 16))
+ return FALSE;
+
+ insn = bfd_get_32 (abfd, buf);
+ if ((insn & 0xffff0000) == LWZ_11_30
+ && bfd_get_32 (abfd, buf + 4) == MTCTR_11
+ && bfd_get_32 (abfd, buf + 8) == BCTR)
+ return TRUE;
+
+ if ((insn & 0xffff0000) == ADDIS_11_30
+ && (bfd_get_32 (abfd, buf + 4) & 0xffff0000) == LWZ_11_11
+ && bfd_get_32 (abfd, buf + 8) == MTCTR_11
+ && bfd_get_32 (abfd, buf + 12) == BCTR)
+ return TRUE;
+ return FALSE;
+}
+
+static bfd_boolean
section_covers_vma (bfd *abfd ATTRIBUTE_UNUSED, asection *section, void *ptr)
{
bfd_vma vma = *(bfd_vma *) ptr;
@@ -2419,12 +2442,22 @@ ppc_elf_get_synthetic_symtab (bfd *abfd,
}
}
+ count = relplt->size / sizeof (Elf32_External_Rela);
+ stub_vma = glink_vma - (bfd_vma) count * 16;
+ /* If the stubs are those for -shared/-pie then we might have
+ multiple stubs for each plt entry. If that is the case then
+ there is no way to associate stubs with their plt entries short
+ of figuring out the GOT pointer value used in the stub. */
+ if (!bfd_get_section_contents (abfd, glink, buf,
+ stub_vma - glink->vma, 4)
+ || ((bfd_get_32 (abfd, buf) & 0xffff0000) != LIS_11
+ && is_pic_glink_stub (abfd, glink, stub_vma - glink->vma - 16)))
+ return 0;
+
slurp_relocs = get_elf_backend_data (abfd)->s->slurp_reloc_table;
if (! (*slurp_relocs) (abfd, relplt, dynsyms, TRUE))
return -1;
- count = relplt->size / sizeof (Elf32_External_Rela);
- stub_vma = glink_vma - (bfd_vma) count * 16;
size = count * sizeof (asymbol);
p = relplt->relocation;
for (i = 0; i < count; i++, p++)
--
Alan Modra
Australia Development Lab, IBM