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

[Emil Velikov]

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)

Thanks
Emil