Check upfront if it's supported, to avoid putting both of them
on the command line.
---
m4/virt-compile-warnings.m4 | 22 ++++++++++++++++++----
1 file changed, 18 insertions(+), 4 deletions(-)
diff --git a/m4/virt-compile-warnings.m4 b/m4/virt-compile-warnings.m4
index 196afa7..6d632f9 100644
--- a/m4/virt-compile-warnings.m4
+++ b/m4/virt-compile-warnings.m4
@@ -156,6 +156,15 @@ AC_DEFUN([LIBVIRT_COMPILE_WARNINGS],[
wantwarn="$wantwarn -Wframe-larger-than=4096"
dnl wantwarn="$wantwarn -Wframe-larger-than=256"
+ AC_CACHE_CHECK([whether the C compiler supports stack-protector-strong],
+ [lv_cv_gcc_fstack_protector_strong], [
+ save_CFLAGS=$CFLAGS
+ CFLAGS='-fstack-protector-strong -Werror'
+ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]])],
+ [lv_cv_gcc_fstack_protector_strong=yes],
+ [lv_cv_gcc_fstack_protector_strong=no])
+ CFLAGS=$save_CFLAGS])
+
# Extra special flags
dnl -fstack-protector stuff passes gl_WARN_ADD with gcc
dnl on Mingw32, but fails when actually used
@@ -164,13 +173,18 @@ AC_DEFUN([LIBVIRT_COMPILE_WARNINGS],[
dnl "error: -fstack-protector not supported for this target [-Werror]"
;;
*-*-linux*)
- dnl Fedora only uses -fstack-protector, but doesn't seem to
- dnl be great overhead in adding -fstack-protector-all instead
+ dnl Prefer -fstack-protector-strong if it's available.
+ dnl There doesn't seem to be great overhead in adding
+ dnl -fstack-protector-all instead of -fstack-protector.
dnl
- dnl We also don't need ssp-buffer-size with -all,
+ dnl We also don't need ssp-buffer-size with -all or -strong,
dnl since functions are protected regardless of buffer size.
dnl wantwarn="$wantwarn --param=ssp-buffer-size=4"
- wantwarn="$wantwarn -fstack-protector-all"
+ if test "$lv_cv_gcc_fstack_protector_strong" = yes; then
+ wantwarn="$wantwarn -fstack-protector-strong"
+ else
+ wantwarn="$wantwarn -fstack-protector-all"
+ fi
;;
*-*-freebsd*)
dnl FreeBSD ships old gcc 4.2.1 which doesn't handle
--
1.8.5.5
--
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