configure.ac: Force use of LLVM shared libs with --enable-opencl v2

If we build clover with LLVM static libraries, then clover and also each
pipe_*.so driver that is built will contain their own static copy of
LLVM.  The recent automake changes have uncovered a problem where
the pipe_*.so drivers try to use clover's LLVM symbols.  This causes
LLVM's static registry objects to be initialized each time
a pipe_*.so driver is loaded by clover.  Initializing these objects
multiple times is not allowed and leads to assertion failures in the
LLVM code.

We can avoid all these problems by having clover and all the pipe_*.so
drivers link against the same LLVM shared library.

https://bugs.freedesktop.org/show_bug.cgi?id=59334
https://bugs.freedesktop.org/show_bug.cgi?id=59534

v2:
  - Fix shared library detection when LLVM is built with CMake

1 files changed, 33 insertions, 5 deletions

diff --git a/configure.ac b/configure.ac
index ec4590dd3ab..ccf95c544b4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -608,8 +608,10 @@ AC_ARG_ENABLE([vdpau],
    [enable_vdpau=auto])
 AC_ARG_ENABLE([opencl],
    [AS_HELP_STRING([--enable-opencl],
-         [enable OpenCL library @<:@default=no@:>@])],
-   [enable_opencl="$enableval"],
+         [enable OpenCL library NOTE: Enabling this option will also enable
+          --with-llvm-shared-libs
+          @<:@default=no@:>@])],
+   [enable_opencl="$enableval" with_llvm_shared_libs="$enableval"],
    [enable_opencl=no])
 AC_ARG_ENABLE([xlib_glx],
     [AS_HELP_STRING([--enable-xlib-glx],
@@ -1896,11 +1898,37 @@ dnl by calling llvm-config --libs ${DRIVER_LLVM_COMPONENTS}, but
 dnl this was causing the same libraries to be appear multiple times
 dnl in LLVM_LIBS.
 
+LLVM_LIBS="`$LLVM_CONFIG --libs ${LLVM_COMPONENTS}`"
+
 if test "x$with_llvm_shared_libs" = xyes; then
     dnl We can't use $LLVM_VERSION because it has 'svn' stripped out,
-    LLVM_LIBS="-lLLVM-`$LLVM_CONFIG --version`"
-else
-    LLVM_LIBS="`$LLVM_CONFIG --libs ${LLVM_COMPONENTS}`"
+    LLVM_SO_NAME=LLVM-`$LLVM_CONFIG --version`
+    AC_CHECK_FILE("$LLVM_LIBDIR/lib$LLVM_SO_NAME.so", llvm_have_one_so=yes,)
+
+    if test "x$llvm_have_one_so" = xyes; then
+        dnl LLVM was built using auto*, so there is only one shared object.
+        LLVM_LIBS="-l$LLVM_SO_NAME"
+    else
+        dnl If LLVM was built with CMake, there will be one shared object per
+        dnl component.
+        AC_CHECK_FILE("$LLVM_LIBDIR/libLLVMTarget.so",,
+                AC_MSG_ERROR([Could not find llvm shared libraries:
+	Please make sure you have built llvm with the --enable-shared option
+	and that your llvm libraries are installed in $LLVM_LIBDIR
+	If you have installed your llvm libraries to a different directory you
+	can use the --with-llvm-prefix= configure flag to specify this directory.
+	NOTE: Mesa is attempting to use llvm shared libraries because you have
+	passed one of the following options to configure:
+		--with-llvm-shared-libs
+		--enable-opencl
+	If you do not want to build with llvm shared libraries and instead want to
+	use llvm static libraries then remove these options from your configure
+	invocation and reconfigure.]))
+
+       dnl We don't need to update LLVM_LIBS in this case because the LLVM
+       dnl install uses a shared object for each compoenent and we have
+       dnl already added all of these objects to LLVM_LIBS. 
+    fi
 fi
 
 AM_CONDITIONAL(HAVE_GALLIUM_SVGA, test "x$HAVE_GALLIUM_SVGA" = xyes)