Re: [dpdk-dev] [PATCH] mk: generate internal library dependencies from DEPDIRS-y automatically

[Christian Ehrhardt <christian.ehrhardt@canonical.com>]

Hi Panu,
thanks for refreshing that - I'm much more happy with ldd output of most
libraries now after build with that.
And it comes much slimmer than my initial approach that touched all lib
makefiles.

Acked-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>

FYI - for anyone else also trying this in a backported way to 16.04 it
needs c6417ce6 and aace9d0b as prereq.

This being done is a nice step taken towards saner linking.
But I still struggle to see how to fix the circular dependency between
librte_eal and librte_mempool.
Maybe now is a time to look at this part of the original threads again to
eventually get apps less overlinked?
=> http://www.dpdk.org/ml/archives/dev/2016-May/039441.html
My naive suggestions in generalized form can be found there (no answer yet):
=>
http://stackoverflow.com/questions/37351699/how-to-create-both-so-files-for-two-circular-depending-libraries


Kind Regards,
Christian



Christian Ehrhardt
Software Engineer, Ubuntu Server
Canonical Ltd

On Tue, Jun 7, 2016 at 12:01 PM, Panu Matilainen <pmatilai@redhat.com>
wrote:

> Up to now dependencies between DPDK internal libraries have been
> untracked at shared library level, requiring applications to know
> about library internal dependencies and often consequently overlinking.
>
> Since the dependencies are already recorded for build ordering in the
> makefiles, we can use that information to generate LDLIBS entries for
> internal libraries automatically.
>
> Also revert commit 8180554d82b3 ("vhost: fix linkage of driver with
> library") which is made redundant by this change.
>
> Signed-off-by: Panu Matilainen <pmatilai@redhat.com>
> ---
>  drivers/net/vhost/Makefile | 1 -
>  mk/rte.lib.mk              | 7 +++++++
>  2 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/vhost/Makefile b/drivers/net/vhost/Makefile
> index 30b91a0..f49a69b 100644
> --- a/drivers/net/vhost/Makefile
> +++ b/drivers/net/vhost/Makefile
> @@ -38,7 +38,6 @@ LIB = librte_pmd_vhost.a
>
>  CFLAGS += -O3
>  CFLAGS += $(WERROR_FLAGS)
> -LDLIBS += -lrte_vhost
>
>  EXPORT_MAP := rte_pmd_vhost_version.map
>
> diff --git a/mk/rte.lib.mk b/mk/rte.lib.mk
> index b420280..1ff403f 100644
> --- a/mk/rte.lib.mk
> +++ b/mk/rte.lib.mk
> @@ -77,6 +77,13 @@ else
>  _CPU_LDFLAGS := $(CPU_LDFLAGS)
>  endif
>
> +# Translate DEPDIRS-y into LDLIBS
> +# Ignore (sub)directory dependencies which do not provide an actual
> library
> +_IGNORE_DIRS = lib/librte_eal/% lib/librte_net lib/librte_compat
> +_DEPDIRS = $(filter-out $(_IGNORE_DIRS),$(DEPDIRS-y))
> +_LDDIRS = $(subst librte_ether,libethdev,$(_DEPDIRS))
> +LDLIBS += $(subst lib/lib,-l,$(_LDDIRS))
> +
>  O_TO_A = $(AR) crDs $(LIB) $(OBJS-y)
>  O_TO_A_STR = $(subst ','\'',$(O_TO_A)) #'# fix syntax highlight
>  O_TO_A_DISP = $(if $(V),"$(O_TO_A_STR)","  AR $(@)")
> --
> 2.5.5
>
>