[pulseaudio-discuss] Enabling --as-needed by default?

[Colin Guthrie]

'Twas brillig, and Tanu Kaskinen at 13/03/12 15:27 did gyre and gimble:
> On Mon, 2012-03-12 at 17:26 +0000, Colin Guthrie wrote:
>> 'Twas brillig, and Tanu Kaskinen at 12/03/12 17:01 did gyre and gimble:
>>> The recent build problems introduced me to the --as-needed linker
>>> option. The as-needed behavior sounds sensible to me, so I wonder why we
>>> don't use it by default?
>>
>> Mostly due to Lennart not liking it IIRC (or was that -Wl,no-undefined?)
>>
>> All of our distro packages are build with as-needed and no-undefined
>> options anyway (via various libtool hacks IIRC) and can be disabled on a
>> per-package basis via some macros.
>>
>> So generally speaking I'm in favour of this if at all possible.
>> (I've personally had --as-needed option disabled in my packages despite
>> distro policy for years as it caused issues long ago and I never
>> actually turned it back on!)
> 
> I interpret this[1] thread so that --as-needed and --no-undefined are
> not used, because they can't be used with the cyclical library setup
> that we have (or had, until [2] added (some of) the duplication back).
> The libraries were set up like they are because Lennart wanted to avoid
> compiling stuff twice. Now we have broken that goal by adding some
> libpulse stuff also to libpulsecommon.
> 
> So, what to do? Currently both --as-needed and --no-undefined seem to
> work, which is nice. OTOH, we compile some stuff twice, which is not so
> nice. There haven't been any complaints about the duplication, but there
> was a complaint immediately after breaking --as-needed (and
> coincidentally also a bug report about 0.9.23 not building either for
> the same reason). My feeling is that the duplication isn't too severe,
> and we should build with --as-needed and --no-undefined, because the
> only reason to avoid them seemed to be that they just couldn't be used,
> but now that has changed. If there are other arguments against the
> flags, I'd like to learn about them.
> 
> [1] http://lists.freedesktop.org/archives/pulseaudio-discuss/2008-October/002402.html
> [2] http://cgit.freedesktop.org/pulseaudio/pulseaudio/commit/src/Makefile.am?id=2de2c735c937c6724c14656acf01ce90f122b903

Well if we add stuff in both libs, does the linker remove the duplicated
stuff from the final build? If so, then perhaps the size of the install
would be a factor for some of the embedded folks? You'll likely know
more than me here and I suspect the size difference is minimal, but of
course it could also translate into memory use during runtime too
perhaps? I won't pretend to understand the intricate details of this!

Col


-- 

Colin Guthrie
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http://colin.guthr.ie/

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