From 5966c61add425d34b708ce9ea1da4f9398e989d0 Mon Sep 17 00:00:00 2001
From: Alex Lin <alexander.s.lin@nasa.gov>
Date: Thu, 2 Jun 2016 08:52:00 -0500
Subject: [PATCH] Build fails on Ubuntu 16.04

Created a configure time test to see if clang will compile ICG correctly.
If the compilation fails, an error message telling the user to go download
clang/llvm from llvm.org is show.

refs #174
---
 autoconf/configure.ac | 19 +++++++++++++++++++
 configure             | 43 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 62 insertions(+)

diff --git a/autoconf/configure.ac b/autoconf/configure.ac
index 9b27630a..a9f47c62 100644
--- a/autoconf/configure.ac
+++ b/autoconf/configure.ac
@@ -16,6 +16,24 @@ AC_DEFUN([AX_LLVM_HOME],[
     AC_SUBST([LLVM_HOME])
 ])
 
+dnl Test if clang will link successfully.  Some systems like Ubuntu 16.04 shipping with clang that does not work.
+AC_DEFUN([AX_TEST_CLANG],[
+    LLVM_INCLUDE_DIR=`$LLVM_CONFIG --includedir`
+    LLVM_ALL_LD_FLAGS=`$LLVM_CONFIG --ldflags --libs`
+    AS_IF([LLVM_SYSTEM_LD_FLAGS=`$LLVM_CONFIG --system-libs 2>/dev/null`],[],[])
+    AC_LANG(C++)
+    AC_DEFINE([__STDC_CONSTANT_MACROS])
+    AC_DEFINE([__STDC_FORMAT_MACROS])
+    AC_DEFINE([__STDC_LIMIT_MACROS])
+    AC_LANG_CONFTEST([AC_LANG_PROGRAM([[#include "llvm/Support/Host.h"]],[[llvm::sys::getDefaultTargetTriple(); return 0; ]])])
+    AC_MSG_CHECKING([if clang works properly])
+    ${CLANG}++ conftest.cpp --std=c++11 -I${LLVM_INCLUDE_DIR} ${LLVM_ALL_LD_FLAGS} ${LLVM_SYSTEM_LD_FLAGS} >&AS_MESSAGE_LOG_FD
+    AS_IF([test $? == 0 ],AC_MSG_RESULT([yes]),
+     [AC_MSG_ERROR([cannot use ${CLANG}. Download clang/llvm directly from http://llvm.org])
+     ])
+    /bin/rm -f a.out
+])
+
 AC_DEFUN([AX_HDF5_HOME],[
     AC_ARG_WITH([hdf5],
                 AS_HELP_STRING([--with-hdf5@<:@=DIR@:>@], [HDF5 root directory]),
@@ -199,6 +217,7 @@ AC_CHECK_FILE([$LLVM_LIB_DIR/libLLVMSupport.a],
 )
 AC_PATH_PROG(CLANG, clang, noclang, "$LLVM_BIN_DIR:$LLVM_HOME/bin:/bin:/usr/bin:/usr/local/bin:/sw/bin")
 AS_IF([test "$ac_cv_path_CLANG" = "noclang"],AC_MSG_ERROR([could not find clang]),[])
+AX_TEST_CLANG
 
 dnl look for udunits in /usr/include and /usr/include/udunits2
 AX_UDUNITS_HOME([])
diff --git a/configure b/configure
index ceb503a6..d8c78b0b 100755
--- a/configure
+++ b/configure
@@ -2251,6 +2251,8 @@ ac_configure="$SHELL $ac_aux_dir/configure"  # Please don't use this var.
 
 
 
+
+
 
 
 
@@ -5749,6 +5751,47 @@ if test "$ac_cv_path_CLANG" = "noclang"; then :
   as_fn_error $? "could not find clang" "$LINENO" 5
 fi
 
+    LLVM_INCLUDE_DIR=`$LLVM_CONFIG --includedir`
+    LLVM_ALL_LD_FLAGS=`$LLVM_CONFIG --ldflags --libs`
+    if LLVM_SYSTEM_LD_FLAGS=`$LLVM_CONFIG --system-libs 2>/dev/null`; then :
+
+fi
+    ac_ext=cpp
+ac_cpp='$CXXCPP $CPPFLAGS'
+ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
+
+    $as_echo "#define __STDC_CONSTANT_MACROS 1" >>confdefs.h
+
+    $as_echo "#define __STDC_FORMAT_MACROS 1" >>confdefs.h
+
+    $as_echo "#define __STDC_LIMIT_MACROS 1" >>confdefs.h
+
+    cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include "llvm/Support/Host.h"
+int
+main ()
+{
+llvm::sys::getDefaultTargetTriple(); return 0;
+  ;
+  return 0;
+}
+_ACEOF
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking if clang works properly" >&5
+$as_echo_n "checking if clang works properly... " >&6; }
+    ${CLANG}++ conftest.cpp --std=c++11 -I${LLVM_INCLUDE_DIR} ${LLVM_ALL_LD_FLAGS} ${LLVM_SYSTEM_LD_FLAGS} >&5
+    if test $? == 0 ; then :
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+else
+  as_fn_error $? "cannot use ${CLANG}. Download clang/llvm directly from http://llvm.org" "$LINENO" 5
+
+fi
+    /bin/rm -f a.out
+
+
 
 
 # Check whether --with-udunits was given.