From b553a0428014636bce4951098e97c60dc18a83ed Mon Sep 17 00:00:00 2001 From: John Snow Date: Tue, 3 Nov 2015 15:43:42 -0500 Subject: [PATCH] configure: disable FORTIFY_SOURCE under clang Some versions of clang may have difficulty compiling glibc headers when -D_FORTIFY_SOURCE is used. For example, Clang++ 3.5.0-9.fc22 cannot compile glibc's stdio headers when -D_FORTIFY_SOURCE=2 is used. This manifests currently as build failures with clang and any arm target. According to LLVM dev Richard Smith, clang does not target or support FORTIFY_SOURCE + glibc, and it should not be relied on. "It's still an unsupported combination, and while it might compile, some of the checks are unlikely to work because they require a frontend inliner to be useful" See: http://lists.llvm.org/pipermail/cfe-dev/2015-November/045846.html Conclusion: disable fortify-source if we appear to be using clang instead of testing for compile success or failure, which may be incidental or not indicative of proper support of the feature. Signed-off-by: John Snow Message-Id: <1446583422-10153-1-git-send-email-jsnow@redhat.com> Signed-off-by: Paolo Bonzini --- configure | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/configure b/configure index 9c726ebada..a1ac1c7699 100755 --- a/configure +++ b/configure @@ -264,6 +264,7 @@ rdma="" gprof="no" debug_tcg="no" debug="no" +fortify_source="" strip_opt="yes" tcg_interpreter="no" bigendian="no" @@ -879,6 +880,7 @@ for opt do debug_tcg="yes" debug="yes" strip_opt="no" + fortify_source="no" ;; --enable-sparse) sparse="yes" ;; @@ -4439,6 +4441,19 @@ if ! compile_object "-Werror"; then ccache_cpp2=yes fi +################################################# +# clang does not support glibc + FORTIFY_SOURCE. + +if test "$fortify_source" != "no"; then + if echo | $cc -dM -E - | grep __clang__ > /dev/null 2>&1 ; then + fortify_source="no"; + elif echo | $cxx -dM -E - | grep __clang__ > /dev/null 2>&1 ; then + fortify_source="no"; + else + fortify_source="yes" + fi +fi + ########################################## # End of CC checks # After here, no more $cc or $ld runs @@ -4446,7 +4461,7 @@ fi if test "$gcov" = "yes" ; then CFLAGS="-fprofile-arcs -ftest-coverage -g $CFLAGS" LDFLAGS="-fprofile-arcs -ftest-coverage $LDFLAGS" -elif test "$debug" = "no" ; then +elif test "$fortify_source" = "yes" ; then CFLAGS="-O2 -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 $CFLAGS" fi