[llvm] r199313 - Add a check to configure that the libstdc++ selected by Clang isn't
Bob Wilson
bob.wilson at apple.com
Wed Jan 15 10:13:34 PST 2014
We shouldn’t be checking this when configure is run with —enable-libcpp. This is breaking all of our buildbots.
On Jan 15, 2014, at 2:31 AM, Chandler Carruth <chandlerc at gmail.com> wrote:
> Author: chandlerc
> Date: Wed Jan 15 04:31:15 2014
> New Revision: 199313
>
> URL: http://llvm.org/viewvc/llvm-project?rev=199313&view=rev
> Log:
> Add a check to configure that the libstdc++ selected by Clang isn't
> libstdc++v4.6. This is quite hard to test directly, so we test for it by
> checking a known missing feature in that version that was added in v4.7.
>
> This should prevent users from upgrading Clang but not GCC and hosting
> with a too-old GCC's libstdc++ and getting strange and hard to debug
> errors when we switch to C++11 by default.
>
> Also, switch several of the macros I introduced to use AC_LANG_SOURCE
> rather than AC_LANG_PROGRAM as we don't need configure's help writing
> our main function (and we don't need such a function at all for most of
> the tests).
>
> Modified:
> llvm/trunk/autoconf/configure.ac
> llvm/trunk/configure
>
> Modified: llvm/trunk/autoconf/configure.ac
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/autoconf/configure.ac?rev=199313&r1=199312&r2=199313&view=diff
> ==============================================================================
> --- llvm/trunk/autoconf/configure.ac (original)
> +++ llvm/trunk/autoconf/configure.ac Wed Jan 15 04:31:15 2014
> @@ -102,15 +102,15 @@ dnl other possible compilers.
> AC_MSG_CHECKING([whether GCC or Clang is our host compiler])
> AC_LANG_PUSH([C++])
> llvm_cv_cxx_compiler=unknown
> -AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#if ! __clang__
> - #error
> - #endif
> - ]])],
> +AC_COMPILE_IFELSE([AC_LANG_SOURCE([[#if ! __clang__
> + #error
> + #endif
> + ]])],
> llvm_cv_cxx_compiler=clang,
> - [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#if ! __GNUC__
> - #error
> - #endif
> - ]])],
> + [AC_COMPILE_IFELSE([AC_LANG_SOURCE([[#if ! __GNUC__
> + #error
> + #endif
> + ]])],
> llvm_cv_cxx_compiler=gcc, [])])
> AC_LANG_POP([C++])
> AC_MSG_RESULT([${llvm_cv_cxx_compiler}])
> @@ -129,7 +129,7 @@ case "$enableval" in
> case "$llvm_cv_cxx_compiler" in
> clang)
> AC_MSG_CHECKING([whether Clang is new enough])
> - AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
> + AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
> #if __clang_major__ < 3 || (__clang_major__ == 3 && __clang_minor__ < 1)
> #error This version of Clang is too old to build LLVM
> #endif
> @@ -140,10 +140,34 @@ case "$enableval" in
> The selected Clang compiler is not new enough to build LLVM. Please upgrade to
> Clang 3.1. You may pass --disable-compiler-version-checks to configure to
> bypass these sanity checks.])])
> +
> + dnl Note that libstdc++4.6 is known broken for C++11 builds. The errors
> + dnl are sometimes deeply confusing though. Here we test for an obvious
> + dnl incomplete feature in 4.6's standard library that was completed in
> + dnl 4.7's.
> + AC_MSG_CHECKING([whether Clang will select a modern C++ standard library])
> + llvm_cv_old_cxxflags="$CXXFLAGS"
> + CXXFLAGS="$CXXFLAGS -std=c++0x"
> + AC_LINK_IFELSE([AC_LANG_SOURCE([[
> +#include <atomic>
> +std::atomic<float> x(0.0f);
> +int main() { return (float)x; }
> +]])],
> + [AC_MSG_RESULT([yes])],
> + [AC_MSG_RESULT([no])
> + AC_MSG_ERROR([
> +We detected a missing feature in the standard C++ library that was known to be
> +missing in libstdc++4.6 and implemented in libstdc++4.7. There are numerous
> +C++11 problems with 4.6's library, and we don't support GCCs or libstdc++ older
> +than 4.7. You will need to update your system and ensure Clang uses the newer
> +standard library.
> +
> +If this error is incorrect or you need to force things to work, you may pass
> +'--disable-compiler-version-checks' to configure to bypass this test.])])
> ;;
> gcc)
> AC_MSG_CHECKING([whether GCC is new enough])
> - AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
> + AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
> #if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 7)
> #error This version of GCC is too old to build LLVM
> #endif
>
> Modified: llvm/trunk/configure
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/configure?rev=199313&r1=199312&r2=199313&view=diff
> ==============================================================================
> --- llvm/trunk/configure (original)
> +++ llvm/trunk/configure Wed Jan 15 04:31:15 2014
> @@ -3593,16 +3593,9 @@ cat confdefs.h >>conftest.$ac_ext
> cat >>conftest.$ac_ext <<_ACEOF
> /* end confdefs.h. */
> #if ! __clang__
> - #error
> - #endif
> + #error
> + #endif
>
> -int
> -main ()
> -{
> -
> - ;
> - return 0;
> -}
> _ACEOF
> rm -f conftest.$ac_objext
> if { (ac_try="$ac_compile"
> @@ -3650,16 +3643,9 @@ cat confdefs.h >>conftest.$ac_ext
> cat >>conftest.$ac_ext <<_ACEOF
> /* end confdefs.h. */
> #if ! __GNUC__
> - #error
> - #endif
> -
> -int
> -main ()
> -{
> + #error
> + #endif
>
> - ;
> - return 0;
> -}
> _ACEOF
> rm -f conftest.$ac_objext
> if { (ac_try="$ac_compile"
> @@ -3748,13 +3734,6 @@ cat >>conftest.$ac_ext <<_ACEOF
> #error This version of Clang is too old to build LLVM
> #endif
>
> -int
> -main ()
> -{
> -
> - ;
> - return 0;
> -}
> _ACEOF
> rm -f conftest.$ac_objext
> if { (ac_try="$ac_compile"
> @@ -3810,6 +3789,88 @@ bypass these sanity checks." >&2;}
> fi
>
> rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
> +
> + { echo "$as_me:$LINENO: checking whether Clang will select a modern C++ standard library" >&5
> +echo $ECHO_N "checking whether Clang will select a modern C++ standard library... $ECHO_C" >&6; }
> + llvm_cv_old_cxxflags="$CXXFLAGS"
> + CXXFLAGS="$CXXFLAGS -std=c++0x"
> + cat >conftest.$ac_ext <<_ACEOF
> +/* confdefs.h. */
> +_ACEOF
> +cat confdefs.h >>conftest.$ac_ext
> +cat >>conftest.$ac_ext <<_ACEOF
> +/* end confdefs.h. */
> +
> +#include <atomic>
> +std::atomic<float> x(0.0f);
> +int main() { return (float)x; }
> +
> +_ACEOF
> +rm -f conftest.$ac_objext conftest$ac_exeext
> +if { (ac_try="$ac_link"
> +case "(($ac_try" in
> + *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
> + *) ac_try_echo=$ac_try;;
> +esac
> +eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
> + (eval "$ac_link") 2>conftest.er1
> + ac_status=$?
> + grep -v '^ *+' conftest.er1 >conftest.err
> + rm -f conftest.er1
> + cat conftest.err >&5
> + echo "$as_me:$LINENO: \$? = $ac_status" >&5
> + (exit $ac_status); } &&
> + { ac_try='test -z "$ac_cxx_werror_flag" || test ! -s conftest.err'
> + { (case "(($ac_try" in
> + *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
> + *) ac_try_echo=$ac_try;;
> +esac
> +eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
> + (eval "$ac_try") 2>&5
> + ac_status=$?
> + echo "$as_me:$LINENO: \$? = $ac_status" >&5
> + (exit $ac_status); }; } &&
> + { ac_try='test -s conftest$ac_exeext'
> + { (case "(($ac_try" in
> + *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
> + *) ac_try_echo=$ac_try;;
> +esac
> +eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
> + (eval "$ac_try") 2>&5
> + ac_status=$?
> + echo "$as_me:$LINENO: \$? = $ac_status" >&5
> + (exit $ac_status); }; }; then
> + { echo "$as_me:$LINENO: result: yes" >&5
> +echo "${ECHO_T}yes" >&6; }
> +else
> + echo "$as_me: failed program was:" >&5
> +sed 's/^/| /' conftest.$ac_ext >&5
> +
> + { echo "$as_me:$LINENO: result: no" >&5
> +echo "${ECHO_T}no" >&6; }
> + { { echo "$as_me:$LINENO: error:
> +We detected a missing feature in the standard C++ library that was known to be
> +missing in libstdc++4.6 and implemented in libstdc++4.7. There are numerous
> +C++11 problems with 4.6's library, and we don't support GCCs or libstdc++ older
> +than 4.7. You will need to update your system and ensure Clang uses the newer
> +standard library.
> +
> +If this error is incorrect or you need to force things to work, you may pass
> +'--disable-compiler-version-checks' to configure to bypass this test." >&5
> +echo "$as_me: error:
> +We detected a missing feature in the standard C++ library that was known to be
> +missing in libstdc++4.6 and implemented in libstdc++4.7. There are numerous
> +C++11 problems with 4.6's library, and we don't support GCCs or libstdc++ older
> +than 4.7. You will need to update your system and ensure Clang uses the newer
> +standard library.
> +
> +If this error is incorrect or you need to force things to work, you may pass
> +'--disable-compiler-version-checks' to configure to bypass this test." >&2;}
> + { (exit 1); exit 1; }; }
> +fi
> +
> +rm -f core conftest.err conftest.$ac_objext \
> + conftest$ac_exeext conftest.$ac_ext
> ;;
> gcc)
> { echo "$as_me:$LINENO: checking whether GCC is new enough" >&5
> @@ -3825,13 +3886,6 @@ cat >>conftest.$ac_ext <<_ACEOF
> #error This version of GCC is too old to build LLVM
> #endif
>
> -int
> -main ()
> -{
> -
> - ;
> - return 0;
> -}
> _ACEOF
> rm -f conftest.$ac_objext
> if { (ac_try="$ac_compile"
> @@ -10606,7 +10660,7 @@ else
> lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
> lt_status=$lt_dlunknown
> cat > conftest.$ac_ext <<EOF
> -#line 10609 "configure"
> +#line 10663 "configure"
> #include "confdefs.h"
>
> #if HAVE_DLFCN_H
>
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
More information about the llvm-commits
mailing list