[Buildroot] [PATCH] ltrace: disable elfutils unwinding when libunwind is used

Thomas Petazzoni thomas.petazzoni at free-electrons.com
Tue Dec 9 07:51:34 UTC 2014


Dear Baruch Siach,

On Tue, 9 Dec 2014 08:02:47 +0200, Baruch Siach wrote:

> > While I agree with the analysis, I don't agree with the proposed fix:
> > ltrace selects elfutils unconditionally (see Config.in), so it is quite
> > weird to see ltrace not using it in the end. So I believe the Config.in
> > *and* ltrace dependencies should be updated to reflect the fact that
> > either unwind or elfutils can be used.
> 
> It turns out that --with-elfutils=no is a misnomer. ltrace depends on libelf 
> regardless of --with-elfutils, so we must have elfutils both in Config.in and 
> in LTRACE_DEPENDENCIES. The only effect of --with-elfutils is on unwinding 
> back-end. Quoting configure.ac:
> 
>   AS_HELP_STRING([--with-elfutils], [Use elfutils libdwfl unwinding support]),
> 
> I'll send a revised version of this patch with a better commit log, and a 
> comment in the code explaining this weirdness.

Aah, ok. Indeed very confusing. Thanks for clarifying this and posting
an updated version with more details!

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com


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