Re: [libvirt] [PATCH v2] Check for --no-copy-dt-needed linker flag
On Mon, Aug 19, 2013 at 11:37:24AM -0600, Eric Blake wrote:
On 08/19/2013 11:28 AM, Guido Günther wrote:
> and use it when available
> ---
> configure.ac | 1 +
> m4/virt-linker-no-indirect.m4 | 30 ++++++++++++++++++++++++++++++
> src/Makefile.am | 9 +++++++++
> tests/Makefile.am | 1 +
> 4 files changed, 41 insertions(+)
> create mode 100644 m4/virt-linker-no-indirect.m4
>
> +AC_DEFUN([LIBVIRT_LINKER_NO_INDIRECT],[
> + AC_MSG_CHECKING([for how to avoid indirect lib deps])
> +
> + 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.
> +++ b/src/Makefile.am
> @@ -1813,6 +1813,7 @@ libvirt_la_LDFLAGS = \
> $(LIBVIRT_NODELETE) \
> $(AM_LDFLAGS) \
> $(RELRO_LDFLAGS) \
> + $(NO_INDIRECT_LDFLAGS) \
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.
Cheers,
-- Guido
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org