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authorJohn Snow2015-11-03 21:43:42 +0100
committerPaolo Bonzini2015-11-05 11:28:02 +0100
commitb553a0428014636bce4951098e97c60dc18a83ed (patch)
treec39d33b6f1f778e8e1ed0ca86c6862b685ab60a9 /configure
parentbackends/hostmem-file: Allow to specify full pathname for backing file (diff)
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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 <jsnow@redhat.com> Message-Id: <1446583422-10153-1-git-send-email-jsnow@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'configure')
-rwxr-xr-xconfigure17
1 files changed, 16 insertions, 1 deletions
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