[pacman-dev] [PATCH] Add "-Wl,--as-needed" to libalpm LDFLAGS.

[Lukas Fleischer]

On Sun, Mar 20, 2011 at 11:01:27AM -0500, Dan McGee wrote:
> On Sat, Mar 19, 2011 at 6:29 PM, Allan McRae <allan at archlinux.org> wrote:
> > On 20/03/11 06:28, Lukas Fleischer wrote:
> >>
> >> Also includes a Debian patch (from #347650) that makes libtool play
> >> nicely with "-Wl,--as-needed".
> >>
> >> Signed-off-by: Lukas Fleischer<archlinux at cryptocrack.de>
> >> ---
> >>  lib/libalpm/Makefile.am |    2 +-
> >>  ltmain.sh               |   14 ++++++++++++++
> >>  2 files changed, 15 insertions(+), 1 deletions(-)
> >>
> >> diff --git a/lib/libalpm/Makefile.am b/lib/libalpm/Makefile.am
> >> index 1bda571..4c329b8 100644
> >> --- a/lib/libalpm/Makefile.am
> >> +++ b/lib/libalpm/Makefile.am
> >> @@ -52,7 +52,7 @@ libalpm_la_SOURCES += \
> >>        md5.h md5.c
> >>  endif
> >>
> >> -libalpm_la_LDFLAGS = -no-undefined -version-info $(LIB_VERSION_INFO)
> >> +libalpm_la_LDFLAGS = -no-undefined -version-info $(LIB_VERSION_INFO)
> >> -Wl,--as-needed
> >
> > This part is not needed.   With the changes below the build obeys the given
> > LDFLAGS.   Unless of course we want to make this the default.
> >
> >
> >>  libalpm_la_LIBADD = $(LTLIBINTL)
> >>
> >>  # vim:set ts=2 sw=2 noet:
> >> diff --git a/ltmain.sh b/ltmain.sh
> >> index 6c02b18..4e98c79 100755
> >> --- a/ltmain.sh
> >> +++ b/ltmain.sh
> >> @@ -5790,6 +5790,11 @@ func_mode_link ()
> >>        arg=$func_stripname_result
> >>        ;;
> >>
> >> +      -Wl,--as-needed|-Wl,--no-as-needed)
> >> +       deplibs="$deplibs $arg"
> >> +       continue
> >> +       ;;
> >> +
> >>        -Wl,*)
> >>        func_stripname '-Wl,' '' "$arg"
> >>        args=$func_stripname_result
> >> @@ -6150,6 +6155,15 @@ func_mode_link ()
> >>        lib=
> >>        found=no
> >>        case $deplib in
> >> +       -Wl,--as-needed|-Wl,--no-as-needed)
> >> +         if test "$linkmode,$pass" = "prog,link"; then
> >> +           compile_deplibs="$deplib $compile_deplibs"
> >> +           finalize_deplibs="$deplib $finalize_deplibs"
> >> +         else
> >> +           deplibs="$deplib $deplibs"
> >> +         fi
> >> +         continue
> >> +         ;;
> >>
> >>  -mt|-mthreads|-kthread|-Kthread|-pthread|-pthreads|--thread-safe|-threads)
> >>          if test "$linkmode,$pass" = "prog,link"; then
> >>            compile_deplibs="$deplib $compile_deplibs"
> >
> > This hack will do until libtool gets it fixed.   Just to clarify what the
> > issues is here, libtool likes to reorder arguments that you pass to it.
> >  That puts -Wl,--as-needed after all the -lfoo statements which stops it
> > working.   And this is a hack as it requires -Wl,--as-needed to be
> > separately specified  (-Wl,--as-needed,--something-else will not work).  But
> > this fix is in widespread use while we wait for the proper fix so I will
> > give it an ack.
> 
> So the tl;dr part of all this- include the ltmain.sh changes but not
> the Makefile.am ones, correct?

Yes, sounds reasonable. Fix libtool ignoring "-Wl,--as-needed" but leave
the decision whether to actually strip indirect dependencies to the
packager.