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[Qemu-devel] [PATCH 1/3] configure: add option to disable -fstack-protec
From: |
Steven Noonan |
Subject: |
[Qemu-devel] [PATCH 1/3] configure: add option to disable -fstack-protector flags |
Date: |
Thu, 9 Jan 2014 13:55:06 -0800 |
From: Steven Noonan <address@hidden>
The -fstack-protector flag family is useful for ensuring safety and for
debugging, but has a performance impact. Here's a boot time comparison between
a QEMU build of qemu-system-arm with and without the -fstack-protector-all
flag:
# WITHOUT -fstack-protector-all
address@hidden ~]# systemd-analyze
Startup finished in 1.744s (kernel) + 11.345s (initrd) + 47.164s
(userspace) = 1min 255ms
# WITH -fstack-protector-all
address@hidden ~]# systemd-analyze
Startup finished in 1.843s (kernel) + 12.262s (initrd) + 1min 3.480s
(userspace) = 1min 17.587s
This is a sizable delta, and some users may wish to disable the flag.
Signed-off-by: Steven Noonan <address@hidden>
Cc: Anthony Liguori <address@hidden>
---
configure | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/configure b/configure
index 07b6be3..c091cdf 100755
--- a/configure
+++ b/configure
@@ -147,6 +147,7 @@ audio_win_int=""
cc_i386=i386-pc-linux-gnu-gcc
libs_qga=""
debug_info="yes"
+stack_protector="yes"
# Don't accept a target_list environment variable.
unset target_list
@@ -879,6 +880,10 @@ for opt do
;;
--disable-werror) werror="no"
;;
+ --enable-stack-protector) stack_protector="yes"
+ ;;
+ --disable-stack-protector) stack_protector="no"
+ ;;
--disable-curses) curses="no"
;;
--enable-curses) curses="yes"
@@ -1117,6 +1122,7 @@ echo " --enable-sparse enable sparse checker"
echo " --disable-sparse disable sparse checker (default)"
echo " --disable-strip disable stripping binaries"
echo " --disable-werror disable compilation abort on warning"
+echo " --disable-stack-protector disable GCC-provided stack protection"
echo " --disable-sdl disable SDL"
echo " --enable-sdl enable SDL"
echo " --disable-gtk disable gtk UI"
@@ -1298,9 +1304,11 @@ for flag in $gcc_flags; do
fi
done
-if compile_prog "-Werror -fstack-protector-all" "" ; then
+if test "$stack_protector" = "yes" ; then
+ if compile_prog "-Werror -fstack-protector-all" "" ; then
QEMU_CFLAGS="$QEMU_CFLAGS -fstack-protector-all"
LIBTOOLFLAGS="$LIBTOOLFLAGS -Wc,-fstack-protector-all"
+ fi
fi
# Workaround for http://gcc.gnu.org/PR55489. Happens with -fPIE/-fPIC and
--
1.8.5.2