[OE-core] [dizzy][PATCH] libunwind: backport patch to link against libgcc_s intead of libgcc

[Jonathan Liu]

On 11 March 2015 at 13:43, Khem Raj <raj.khem at gmail.com> wrote:
>
>> On Mar 10, 2015, at 7:33 PM, Jonathan Liu <net147 at gmail.com> wrote:
>>
>> Signed-off-by: Jonathan Liu <net147 at gmail.com>
>> ---
>> ...-libunwind-to-libgcc_s-rather-than-libgcc.patch | 42 ++++++++++++++++++++++
>> meta/recipes-support/libunwind/libunwind_1.1.bb    |  1 +
>> 2 files changed, 43 insertions(+)
>> create mode 100644 meta/recipes-support/libunwind/libunwind-1.1/Link-libunwind-to-libgcc_s-rather-than-libgcc.patch
>>
>> diff --git a/meta/recipes-support/libunwind/libunwind-1.1/Link-libunwind-to-libgcc_s-rather-than-libgcc.patch b/meta/recipes-support/libunwind/libunwind-1.1/Link-libunwind-to-libgcc_s-rather-than-libgcc.patch
>> new file mode 100644
>> index 0000000..0e55c91
>> --- /dev/null
>> +++ b/meta/recipes-support/libunwind/libunwind-1.1/Link-libunwind-to-libgcc_s-rather-than-libgcc.patch
>> @@ -0,0 +1,42 @@
>> +From 508ca17a7be01d1cc960d9a07d0af4513948fb8d Mon Sep 17 00:00:00 2001
>> +From: Thierry Reding <treding at nvidia.com>
>> +Date: Fri, 27 Jun 2014 08:40:33 +0200
>> +Subject: [PATCH] Link libunwind to libgcc_s rather than libgcc
>> +
>> +For some architectures, -lgcc and -lgcc_s are not equivalent. On ARM for
>> +example, libgcc_s.so.1 contains some symbols needed by libunwind which
>> +are not present in libgcc.
>> +
>> +This causes the following link error when building the X.Org X server
>> +with libunwind support:
>> +
>> +       CCLD     Xorg
>> +     /usr/lib/libunwind.so: undefined reference to `__aeabi_unwind_cpp_pr0'
>> +     /usr/lib/libunwind.so: undefined reference to `__aeabi_unwind_cpp_pr1'
>> +
>> +Linking against libgcc_s explicitly solves this problem.
>> +
>
> have you tried it at runtime too ?
>
strace 4.9 with libunwind PACKAGECONFIG wouldn't build on master
without the patch.
If I add strace 4.9 recipe to dizzy branch, using the libunwind
PACKAGECONFIG also fails to build without the patch. It gives the same
errors during linking.

I tested at runtime on master branch which has libunwind 1.1 running
strace 4.9 on the target and didn't notice any issues. I haven't
tested on dizzy branch at runtime though.

Regards,
Jonathan