On 28/02/17 15:27, jan.som...@dlr.de wrote:
-----Ursprüngliche Nachricht-----
Von: Sebastian Huber [mailto:sebastian.hu...@embedded-brains.de]
Gesendet: Montag, 27. Februar 2017 15:25
An: Sommer, Jan; devel@rtems.org
Betreff: Re: AW: AW: AW: Undefined reference to
`__sync_bool_compare_and_swap_4' for some Leon configurations with
gfortran
On 27/02/17 15:15, jan.som...@dlr.de wrote:
-----Ursprüngliche Nachricht-----
Von: Sebastian Huber [mailto:sebastian.hu...@embedded-brains.de]
Gesendet: Montag, 27. Februar 2017 15:11
An: Sommer, Jan;devel@rtems.org
Betreff: Re: AW: AW: Undefined reference to
`__sync_bool_compare_and_swap_4' for some Leon configurations with
gfortran
On 27/02/17 15:08,jan.som...@dlr.de wrote:
Ok, thanks for the clarification.
I will try to create a patch for gcc and put rtems CC for the discussion.
Another option would be to provide the __sync_() stuff also via libatomic.
True. I will ask on the gcc mailinglist what they would prefer.
This __sync_() stuff seems to be used in several places in GCC. So, changing
libbacktrace is probably not enough. We need a general solution for the
__sync_() builtins on RTEMS. I don't think GCC can be changed to emit
__atomic_() calls for the __sync_() builtins (I would still try to ask). The
libgcc or
libatomic is probably a good place to add them for RTEMS as functions
implemented via __atomic_() builtins.
I updated the __sync-check of libbacktrace and now the undefined references are
gone and my test program compiles.
If there are no objections I would try to push something like the attached
patch upstream. Do you have any suggestions to which branches?
I thought about trunk and the gcc-6 branch or do we need further backports for
older RTEMS versions?
I don't think this is the way to go. Firstly, this is certainly not a
SPARC-specific problem. Secondly, RTEMS is multi-threaded, are you sure
you can simply disable this feature? RTEMS supports C11 atomic
operations which includes libatomic support. However, we lack the
__sync_* builtin support on targets without atomic operations in
hardware. This is the problem we should fix. We should provide these
functions either in libgcc or in libatomic.
One open question is why is there a libbacktrace dependency in
libgfortran? Does this add any value to embedded targets?
--
Sebastian Huber, embedded brains GmbH
Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone : +49 89 189 47 41-16
Fax : +49 89 189 47 41-09
E-Mail : sebastian.hu...@embedded-brains.de
PGP : Public key available on request.
Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
_______________________________________________
devel mailing list
devel@rtems.org
http://lists.rtems.org/mailman/listinfo/devel
