From: Aaron Conole <aconole@redhat.com>
To: Luca Boccassi <bluca@debian.org>
Cc: Bruce Richardson <bruce.richardson@intel.com>, dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH 0/6] next-build: create both static and shared libs
Date: Mon, 18 Dec 2017 13:05:14 -0500 [thread overview]
Message-ID: <f7tvah3zzc5.fsf@dhcp-25.97.bos.redhat.com> (raw)
In-Reply-To: <1513167052.15861.26.camel@debian.org> (Luca Boccassi's message of "Wed, 13 Dec 2017 12:10:52 +0000")
Luca Boccassi <bluca@debian.org> writes:
> On Tue, 2017-12-12 at 17:14 +0000, Bruce Richardson wrote:
>> On Tue, Dec 12, 2017 at 04:59:34PM +0000, Bruce Richardson wrote:
>> > This patchset changes the meson+ninja build system to always create
>> > both
>> > static and shared libraries when doing a build. The applications
>> > compiled
>> > as part of a build use either the shared or static libraries
>> > depending on
>> > what the default_library build setting is.
>> >
>> > NOTE:
>> > The main difficulty with this change is adjusting the pkgconfig
>> > file so
>> > that external apps, like the examples, can be built using either
>> > the static
>> > or shared libraries. One of the key issues was the fact that
>> > running
>> > "pkg-config --static --libs libdpdk" outputs first the normal libs,
>> > and
>> > then the extra static ones. This is a problem because the driver
>> > libs are
>> > for static only builds, but need to come before, not after the
>> > standard
>> > DDPK libraries. It also procludes adding in the -Wl,-Bstatic flag
>> > into the output for the standard libraries to link them statically.
>> >
>> > There were two options considered for mananging the pkg-config
>> > settings.
>> > 1. Creating a separate .pc file for static builds with exactly the
>> > flags
>> > needed.
>> > 2. Modifying the single .pc file so that it was "good enough" to
>> > enable
>> > static builds without too much work.
>> >
>> > For this version of this set, I took option #2. To link using
>> > dynamic libs,
>> > all is as normal, to use static libs, the user needs to prepend
>> > "-Wl,-Bstatic" before the "pkgconfig --static" library output. This
>> > can be
>> > seen in the changes to the example application makefiles, which now
>> > support
>> > building the examples using shared or static DPDK libs.
>> >
>>
>> Just to emphasise that I'm looking for input into whether I took the
>> right choice here. Option #1 has some advantages in that we can tune
>> the
>> output specifically for the static build case, but I wasn't sure
>> whether
>> it would be the done thing to have two different .pc files for a
>> single
>> package. Feedback from packagers welcome!
>>
>> /Bruce
>
> I don't link #1 too much - too "special". I think an additional flag is
> more friendly.
I agree with this.
> A good solution would be a Cflags.private feature, sadly that is not
> supported by pkgconfig despite many requests for it.
>
> A possible way to sugar-coat it could be to add a custom variable, and
> then instruct the users to do something like:
>
> $(shell pkg-config --variable=ldflags.static libdpdk) $(shell pkg-
> config --static --libs libdpdk)
I don't think this is needed. Most linkers (and libtool based linkers
as well) have no 'distinction' between static / dynamic - just the
static option gets passed.
In this case, I think it's fine to require the application build system
to expose such a distinct option to the user doing the builds. There's
generally no good reasons to want static builds (well... okay that's a
bit strong, but hopefully I don't get my head chewed off) anyway, so
making them slightly more work is okay by me.
> Unfortunately, again, --variable cannot be used together with --libs in
> the same call.
next prev parent reply other threads:[~2017-12-18 18:05 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-12 16:59 Bruce Richardson
2017-12-12 16:59 ` [dpdk-dev] [PATCH 1/6] build: remove library special cases Bruce Richardson
2017-12-12 16:59 ` [dpdk-dev] [PATCH 2/6] eal: fix list of source files to meson build Bruce Richardson
2017-12-12 16:59 ` [dpdk-dev] [PATCH 3/6] build: build all libs and drivers as both static and shared Bruce Richardson
2017-12-12 16:59 ` [dpdk-dev] [PATCH 4/6] build: change default library type to static Bruce Richardson
2017-12-12 16:59 ` [dpdk-dev] [PATCH 5/6] build: symlink drivers to library directory Bruce Richardson
2017-12-12 16:59 ` [dpdk-dev] [PATCH 6/6] examples: enable linking examples both static and shared Bruce Richardson
2017-12-12 17:14 ` [dpdk-dev] [PATCH 0/6] next-build: create both static and shared libs Bruce Richardson
2017-12-13 12:10 ` Luca Boccassi
2017-12-13 13:28 ` Bruce Richardson
2017-12-18 18:05 ` Aaron Conole [this message]
2017-12-19 10:07 ` Bruce Richardson
2017-12-13 12:11 ` Luca Boccassi
2017-12-15 12:02 ` Bruce Richardson
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