diff mbox series

[v3,7/7] build/pkg-config: prevent overlinking

Message ID 20200630141433.818517-8-bruce.richardson@intel.com (mailing list archive)
State Accepted, archived
Delegated to: Thomas Monjalon
Headers show
Series improve DPDK static builds with meson | expand

Checks

Context Check Description
ci/Intel-compilation success Compilation OK
ci/travis-robot success Travis build: passed
ci/checkpatch success coding style OK

Commit Message

Bruce Richardson June 30, 2020, 2:14 p.m. UTC
Add the --as-needed linker flag to the DPDK library list in the pkg-config
file so as to prevent overlinking. Without this flag, when linking
statically using flags from $(pkg-config --static --libs libdpdk), all DPDK
drivers and libs were statically linked in, but the binary was also
requiring all the shared versions be present to run.

The real root-cause of this issue is that the DPDK libraries need to be
duplicated in the linker command when doing static linking, due to the
behaviour of pkg-config, but since that behaviour cannot be easily changed,
this is a simple workaround to avoid problems.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Luca Boccassi <bluca@debian.org>
Acked-by: Sunil Pai G <sunil.pai.g@intel.com>
---
 buildtools/pkg-config/meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Thomas Monjalon July 1, 2020, 7:56 a.m. UTC | #1
30/06/2020 16:14, Bruce Richardson:
> Add the --as-needed linker flag to the DPDK library list in the pkg-config
> file so as to prevent overlinking. Without this flag, when linking
> statically using flags from $(pkg-config --static --libs libdpdk), all DPDK
> drivers and libs were statically linked in, but the binary was also
> requiring all the shared versions be present to run.
> 
> The real root-cause of this issue is that the DPDK libraries need to be
> duplicated in the linker command when doing static linking, due to the
> behaviour of pkg-config, but since that behaviour cannot be easily changed,
> this is a simple workaround to avoid problems.

It deserves to give a more detailed explanation here.
Bruce Richardson July 1, 2020, 8:58 a.m. UTC | #2
On Wed, Jul 01, 2020 at 09:56:13AM +0200, Thomas Monjalon wrote:
> 30/06/2020 16:14, Bruce Richardson:
> > Add the --as-needed linker flag to the DPDK library list in the pkg-config
> > file so as to prevent overlinking. Without this flag, when linking
> > statically using flags from $(pkg-config --static --libs libdpdk), all DPDK
> > drivers and libs were statically linked in, but the binary was also
> > requiring all the shared versions be present to run.
> > 
> > The real root-cause of this issue is that the DPDK libraries need to be
> > duplicated in the linker command when doing static linking, due to the
> > behaviour of pkg-config, but since that behaviour cannot be easily changed,
> > this is a simple workaround to avoid problems.
> 
> It deserves to give a more detailed explanation here.
>
It's already explained in commit log for patch 5 and in the code comments
added in patch 5 also, so I didn't think it was necessary again. However
can add in a V4, if needed.

/Bruce
diff mbox series

Patch

diff --git a/buildtools/pkg-config/meson.build b/buildtools/pkg-config/meson.build
index e043c5ee1..5c1e31c4d 100644
--- a/buildtools/pkg-config/meson.build
+++ b/buildtools/pkg-config/meson.build
@@ -23,7 +23,7 @@  Use libdpdk.pc instead of this file to query DPDK compile/link arguments''',
 	version: meson.project_version(),
 	subdirs: [get_option('include_subdir_arch'), '.'],
 	extra_cflags: pkg_extra_cflags,
-	libraries: dpdk_libraries,
+	libraries: ['-Wl,--as-needed'] + dpdk_libraries,
 	libraries_private: dpdk_extra_ldflags)
 
 pkg.generate(name: 'DPDK', # main DPDK pkgconfig file