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[Qemu-devel] [PATCH v2] configure: disable FORTIFY_SOURCE under clang
From: |
John Snow |
Subject: |
[Qemu-devel] [PATCH v2] configure: disable FORTIFY_SOURCE under clang |
Date: |
Tue, 3 Nov 2015 15:43:42 -0500 |
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 <address@hidden>
---
configure | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/configure b/configure
index 7a1d08d..4d74fcc 100755
--- a/configure
+++ b/configure
@@ -261,6 +261,7 @@ rdma=""
gprof="no"
debug_tcg="no"
debug="no"
+fortify_source=""
strip_opt="yes"
tcg_interpreter="no"
bigendian="no"
@@ -876,6 +877,7 @@ for opt do
debug_tcg="yes"
debug="yes"
strip_opt="no"
+ fortify_source="no"
;;
--enable-sparse) sparse="yes"
;;
@@ -4435,6 +4437,19 @@ 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 $ld runs
@@ -4442,7 +4457,7 @@ fi
if test "$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
--
2.4.3
- [Qemu-devel] [PATCH v2] configure: disable FORTIFY_SOURCE under clang,
John Snow <=