[dpdk-dev] [PATCH v2] mk: fix objects/library order when linking

[Thomas Monjalon]

2015-12-04 18:31, Adrien Mazarguil:
> On Fri, Dec 04, 2015 at 06:11:03PM +0100, David Marchand wrote:
> > The initial problem has been seen while building mlx4 pmd as a shared library
> > on Ubuntu 14.04 (gcc 4.8.4-2ubuntu1~14.04).
> > 
> > Resulting .so will lack the DT_NEEDED entry for libibverbs:
> > 
> > marchand at ubuntu1404:~/dpdk$ ldd ./build/lib/librte_pmd_mlx4.so
> > 	linux-vdso.so.1 =>  (0x00007fff87ebb000)
> > 	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f2ced21a000)
> > 	/lib64/ld-linux-x86-64.so.2 (0x00007f2ced821000)
> > 
> > And trying to load it in testpmd triggers this error:
> > 
> > [...]
> > EAL: librte_pmd_mlx4.so: undefined symbol: ibv_query_port
> > [...]
> > 
> > After some strace, the problem comes from the --as-needed option passed to the
> > linker.
> > 
> > It is safer to specify libraries we depend on after the objects we are linking
> > into a shared library, especially when the linker is invoked with options like
> > --as-needed.
> > 
> > Fixes: bef06a8a0655 ("mk: set library dependencies in shared object file")
> > 
> > Signed-off-by: David Marchand <david.marchand at 6wind.com>
> > ---
> > 
> > Changes since v1:
> > - added some details in commitlog since Thomas does not like "safer"
> >   argument :-)

Yes, that's better justified with these details :)

> Obvious issue that did not show up in our tests under Debian.
> 
> Acked-by: Adrien Mazarguil <adrien.mazarguil at 6wind.com>

Applied, thanks