Re: [libvirt] [PATCH v2] Check for --no-copy-dt-needed linker flag
On Mon, Aug 19, 2013 at 01:36:36PM -0600, Eric Blake wrote:
On 08/19/2013 12:07 PM, Guido Günther wrote:
>>> + NO_INDIRECT_LDFLAGS=
>>> + `$LD --help 2>&1 | grep --
"--no-copy-dt-needed-entries" >/dev/null` && \
>>
>> Doesn't do what you think (it tries to execute the output of grep -
>> which is thankfully empty on both success and failure). Also wastes a
>> fork on grep, compared to the simpler:
>
> I was looking following virt-linker-relro.m4 and I'm getting the correct
> result since the output is always empty but for the non matching case
> grep exits with 1. However
>
>>
>> case `$LD --help 2>&1` in
>> *--no-copy-dt-needed-entries*) NO_INDIRECT_LDFLAGS=... ;;
>> esac
>
> this looks nicer.
Oh sure - blame copy-and-paste of bad habits :)
Not actually blaming more following current practice. We're not using
AM_LDFLAGS everywhere. This should be a sperate cleanup in case this is
considered useful. Which I think would be since we're misusing LDADDS in
e.g. tests/Makefile.am for cflags, linkerflags and actually adding
additional libraries.
Cheers,
-- Guido
>> Why aren't you building this directly into $(AM_LDFLAGS) once, rather
>> than having to copy it into each and every library recipe?
>>
>> Why only src/ and tests/? What about tools/ and daemon/?
>
> Again following the above example. I'll come up with a v3.
For a v3, it might be nice to have two patches - one that cleans up the
bad habits of RELRO handling, and the second that extends it with the
cleaner idioms. Thanks for putting up with me :)
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org