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From: Thomas Monjalon <thomas@monjalon.net>
To: Bruce Richardson <bruce.richardson@intel.com>
Cc: dev@dpdk.org, konstantin.ananyev@intel.com, aconole@redhat.com
Subject: Re: [dpdk-dev] [PATCH 0/2] remove use of weak functions from libraries
Date: Wed, 05 Jun 2019 16:41:25 +0200	[thread overview]
Message-ID: <1667240.nEyWy9ANPa@xps> (raw)
In-Reply-To: <20190410134517.63896-1-bruce.richardson@intel.com>

10/04/2019 15:45, Bruce Richardson:
> Weak functions don't work well with static library builds as the linker
> always picks the first version of a function irrespective of whether it is
> weak or not. The solution to this is to use the "whole-archive" flag when
> linking, but this has the nasty side-effect that it causes the resulting
> binary to be larger than it needs to be.
> 
> 
> A further problem with this approach of using "whole-archive" is that one
> either needs to link all libraries with this flag or track what libraries
> need it or not - the latter being especially a problem for apps not using
> the DPDK build system itself (i.e. most apps not shipped with DPDK itself).
> For meson builds this information needs to make its way all the way through
> to the pkgconfig file generated - not a trivial undertaking.
> 
> Thankfully, though, the use of weak functions is limited to use for
> multiple functions within a single library, meaning that when the lib is
> being built, the build system itself can know whether the "weak" function
> is needed or not. This allows us to change the weak function to a
> conditionally compiled regular function used in fallback case. This makes
> the need for "whole-archive" flag, and any special linking measures for the
> library, go away.
> 
> [This set does not touch the drivers, only the libraries, since there are
> other special linker flags needed for drivers in general, making the
> problem less severe for driver .a files.]
> 
> Bruce Richardson (2):
>   acl: remove use of weak functions
>   bpf: remove use of weak functions

Applied, thanks



      parent reply	other threads:[~2019-06-05 14:41 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-10 13:45 Bruce Richardson
2019-04-10 13:45 ` Bruce Richardson
2019-04-10 13:45 ` [dpdk-dev] [PATCH 1/2] acl: remove use of weak functions Bruce Richardson
2019-04-10 13:45   ` Bruce Richardson
2019-04-10 13:54   ` Aaron Conole
2019-04-10 13:54     ` Aaron Conole
2019-04-10 14:02     ` Bruce Richardson
2019-04-10 14:02       ` Bruce Richardson
2019-04-10 14:08       ` Aaron Conole
2019-04-10 14:08         ` Aaron Conole
2019-04-10 14:57   ` Ananyev, Konstantin
2019-04-10 14:57     ` Ananyev, Konstantin
2019-04-10 13:45 ` [dpdk-dev] [PATCH 2/2] bpf: " Bruce Richardson
2019-04-10 13:45   ` Bruce Richardson
2019-04-10 14:07   ` Aaron Conole
2019-04-10 14:07     ` Aaron Conole
2019-04-10 14:27     ` Bruce Richardson
2019-04-10 14:27       ` Bruce Richardson
2019-04-10 14:57   ` Ananyev, Konstantin
2019-04-10 14:57     ` Ananyev, Konstantin
2019-05-27 14:13 ` [dpdk-dev] [PATCH 0/2] remove use of weak functions from libraries David Marchand
2019-05-27 15:41   ` Bruce Richardson
2019-05-27 20:57     ` Aaron Conole
2019-05-28  8:06       ` Bruce Richardson
2019-06-05 14:41 ` Thomas Monjalon [this message]

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