[Mesa-dev] [PATCH] Use IMP_LIB_EXT when checking for LLVM shared libraries

[Tom Stellard]

On Mon, Sep 07, 2015 at 10:06:49AM +0100, Emil Velikov wrote:
> Hi Jon,
> 
> On 4 September 2015 at 14:00, Jon TURNEY <jon.turney at dronecode.org.uk> wrote:
> > When checking for LLVM shared libraries, use IMP_LIB_EXT for the extension for
> > shared libraries appropriate to the target, rather than hardcoding '.so'
> >
> > Also add some comments to explain why we have this circus of pain.
> >
> > Signed-off-by: Jon TURNEY <jon.turney at dronecode.org.uk>
> > ---
> >  configure.ac | 33 +++++++++++++++++++++++++++------
> >  1 file changed, 27 insertions(+), 6 deletions(-)
> >
> > diff --git a/configure.ac b/configure.ac
> > index 90ba4fe..9960dd0 100644
> > --- a/configure.ac
> > +++ b/configure.ac
> > @@ -533,15 +533,32 @@ AM_CONDITIONAL(HAVE_COMPAT_SYMLINKS, test "x$HAVE_COMPAT_SYMLINKS" = xyes)
> >  dnl
> >  dnl library names
> >  dnl
> > +dnl Unfortunately we need to do a few things that libtool can't help us with,
> > +dnl so we need some knowledge of shared library filenames:
> > +dnl
> > +dnl LIB_EXT is the extension used when creating symlinks for alternate
> > +dnl filenames for a shared library which will be dynamically loaded
> > +dnl
> > +dnl IMP_LIB_EXT is the extension used when checking for the presence of a
> > +dnl the file for a shared library we wish to link with
> > +dnl
> >  case "$host_os" in
> >  darwin* )
> > -    LIB_EXT='dylib' ;;
> > +    LIB_EXT='dylib'
> > +    IMP_LIB_EXT=$LIB_EXT
> > +    ;;
> >  cygwin* )
> > -    LIB_EXT='dll' ;;
> > +    LIB_EXT='dll'
> > +    IMP_LIB_EXT='dll.a'
> > +    ;;
> >  aix* )
> > -    LIB_EXT='a' ;;
> > +    LIB_EXT='a'
> > +    IMP_LIB_EXT=$LIB_EXT
> > +    ;;
> >  * )
> > -    LIB_EXT='so' ;;
> > +    LIB_EXT='so'
> > +    IMP_LIB_EXT=$LIB_EXT
> > +    ;;
> >  esac
> >
> >  AC_SUBST([LIB_EXT])
> > @@ -2163,10 +2180,14 @@ if test "x$MESA_LLVM" != x0; then
> >
> >      LLVM_LIBS="`$LLVM_CONFIG --libs ${LLVM_COMPONENTS}`"
> >
> > +    dnl llvm-config may not give the right answer when llvm is a built as a
> > +    dnl single shared library, so we must work the library name out for
> > +    dnl ourselves.
> > +    dnl (See https://llvm.org/bugs/show_bug.cgi?id=6823)
> >      if test "x$enable_llvm_shared_libs" = xyes; then
> >          dnl We can't use $LLVM_VERSION because it has 'svn' stripped out,
> >          LLVM_SO_NAME=LLVM-`$LLVM_CONFIG --version`
> > -        AS_IF([test -f "$LLVM_LIBDIR/lib$LLVM_SO_NAME.so"], [llvm_have_one_so=yes])
> > +        AS_IF([test -f "$LLVM_LIBDIR/lib$LLVM_SO_NAME.$IMP_LIB_EXT"], [llvm_have_one_so=yes])
> >
> >          if test "x$llvm_have_one_so" = xyes; then
> >              dnl LLVM was built using auto*, so there is only one shared object.
> > @@ -2174,7 +2195,7 @@ if test "x$MESA_LLVM" != x0; then
> >          else
> >              dnl If LLVM was built with CMake, there will be one shared object per
> >              dnl component.
> > -            AS_IF([test ! -f "$LLVM_LIBDIR/libLLVMTarget.so"],
> > +            AS_IF([test ! -f "$LLVM_LIBDIR/libLLVMTarget.$IMP_LIB_EXT"],
> Fwiw I would prefer if we drop support for non have_one_so file LLVM
> builds and just fail miserably, rather than having this around :-)
> I suspect that either a) llvm people may have dropped support for it,
> b) it's tested/used extremely rarely or c) busted with latest
> llvm/mesa.
> 
> Tom how do you feel on the subject ? Can we drop this workaround,
> pretty please (/me does the puppy eyes)
> 

I have an LLVM patch which I need to commit that should simplify a lot of this code.
Lets hold this discussion until I get a chance to clean this up.

I don't think we need to hold up this patch, though, it looks fine to me.

-Tom

> Thanks
> Emil
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