Commit 218bb57 ("build-sys: check static linking of UBSAN", 2018-02-13) adds a small test program to check whether ubsan works even when configuring with --static. This added program is used to detect all sanitizers, which breaks ASan's detection since the compilation fails with -fsanitize=address, at least with gcc 5.4.0 and 7.2.0:
qemu-conf.c: In function ‘main’: qemu-conf.c:3:20: error: integer overflow in expression [-Werror=overflow] return INT32_MIN / -1; ^ cc1: all warnings being treated as errors Fix it by: - Changing the test program to one that incurs undefined behaviour that isn't detected at compile-time, even with -fsanitize=address. - To be extra safe (since compilers might evolve and eventually figure out the UB at compile-time), use this newly-added test only when checking for UBSan; use the skeleton otherwise. Signed-off-by: Emilio G. Cota <c...@braap.org> --- configure | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/configure b/configure index 913e148..56f647f 100755 --- a/configure +++ b/configure @@ -5306,13 +5306,13 @@ fi ########################################## # checks for sanitizers -# we could use a simple skeleton for flags checks, but this also -# detect the static linking issue of ubsan, see also: +# Use this program to detect the static linking issue of ubsan; see # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84285 cat > $TMPC << EOF -#include <stdint.h> -int main(void) { - return INT32_MIN / -1; +int main(int argc, char **argv) { + int k = 0x7fffffff; + k += argc; + return 0; } EOF @@ -5322,12 +5322,16 @@ have_asan_iface_h=no have_asan_iface_fiber=no if test "$sanitizers" = "yes" ; then + if compile_prog "$CPU_CFLAGS -Werror -fsanitize=undefined" ""; then + have_ubsan=yes + fi + + # Use the skeleton for all other sanitizer checks + write_c_skeleton + if compile_prog "$CPU_CFLAGS -Werror -fsanitize=address" ""; then have_asan=yes fi - if compile_prog "$CPU_CFLAGS -Werror -fsanitize=undefined" ""; then - have_ubsan=yes - fi if check_include "sanitizer/asan_interface.h" ; then have_asan_iface_h=yes -- 2.7.4