ld bug?
Alan Modra
amodra@bigpond.net.au
Wed Aug 6 01:26:00 GMT 2003
On Tue, Aug 05, 2003 at 10:59:09AM -0400, Michal Ostrowski wrote:
> Hi,
>
> I have a bunch of object files that when linked together (to build
> "troff") result in certain symbols being assigned the same location in
> memory.
>
> This was achieved with gcc-3.2.3 (c++) and,
>
> powerpc64-linux-ld -v
> GNU ld version 2.14.90 20030805
>
> The problem is that we have a couple of symbols as follow:
>
> 84: 0000000020015c10 8 NOTYPE LOCAL DEFAULT 26 soft_hyphen_char
> 2986: 0000000020015c18 8 NOTYPE GLOBAL DEFAULT 26 global_special_fonts
>
>
> However, we also have (from .rela.dyn):
> 000020015c10 004700000013 R_PPC_COPY 0000000020015c10 _ZTVN10__cxxabiv117__c + 0
>
> This causes ld.so to copy 88 bytes of data to the location of
> soft_hyphen_char (and the symbols that follow it).
[snip]
Hmm, yes. A ld map shows
.bss 0x0000000010085b30 0x4248
*(.dynbss)
*fill* 0x0000000010085b30 0x0 00
*(.bss .bss.* .gnu.linkonce.b.*)
.bss 0x0000000010085b30 0x1 ./crtbegin.o
*fill* 0x0000000010085b31 0x7 00
.bss 0x0000000010085b38 0xc8 ./env.o
Note the zero .dynbss allocation. It should be 312 bytes in this case.
The problem was uncoverd by this patch:
2003-07-10 Alan Modra <amodra@bigpond.net.au>
(ppc64_elf_build_stubs): Check for stub sections in stub bfd by
testing section flags.
Fixed like this.
* elflink.c (_bfd_elf_create_dynamic_sections): Mark .dynbss with
SEC_LINKER_CREATED.
Index: bfd/elflink.c
===================================================================
RCS file: /cvs/src/src/bfd/elflink.c,v
retrieving revision 1.42
diff -u -p -r1.42 elflink.c
--- bfd/elflink.c 4 Aug 2003 09:39:46 -0000 1.42
+++ bfd/elflink.c 6 Aug 2003 01:22:35 -0000
@@ -309,7 +309,7 @@ _bfd_elf_create_dynamic_sections (bfd *a
section into the .bss section of the final image. */
s = bfd_make_section (abfd, ".dynbss");
if (s == NULL
- || ! bfd_set_section_flags (abfd, s, SEC_ALLOC))
+ || ! bfd_set_section_flags (abfd, s, SEC_ALLOC | SEC_LINKER_CREATED))
return FALSE;
/* The .rel[a].bss section holds copy relocs. This section is not
--
Alan Modra
IBM OzLabs - Linux Technology Centre
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