[Mesa-dev] [PATCH 2/2] travis-ci: Add libunwind-dev to gallium/make builds

[Gert Wollny]

Am Montag, den 11.09.2017, 17:05 +0100 schrieb Emil Velikov:
> On 10 September 2017 at 12:17, Gert Wollny <gw.fossdev at gmail.com>
> wrote:
> > configure picks up libunwind automatically if it is available and
> > links libmesagallium against it. Because static linking is used
> > all targets that use libmesagallium also need to link against
> > libunwind
> > in this case, and this should be checked on travis-ci.
> 
> I'm slightly confused by the sentence, what do you mean with "Because
> static linking is used"?

If you have a dependency chain 

  Exe -> libA -> libB

in which Exe does not use symbols from libB, then libB can be omitted
when dynamically linking against libA (Exe will not directly depend on
libB, the same one achieves by specifying --as-needed as linker flag),
and I assume that all targets that link against libmesagallium don't
actually use symbols from libunwind directly.

In static linking also the symbols that are used by libA need to be
available, hence libB needs to be specified, hence the comment.

> Please explicitly enable unwind on the configure line.
> With that the patch is
> Reviewed-by: Emil Velikov <emil.velikov at collabora.com>

Best, 
Gert