The configure script used to compile some code which dereferences memory with ubsan to verify the compiler can link with ubsan library which detects dereferencing of uninitialized memory. However, as the dereferenced memory was allocated in the same code, GCC can statically detect the unitialized memory dereference and emit maybe-uninitialized warning. If -Werror is set, this becomes an error, and the configure script incorrectly thinks the error indicates the compiler cannot use ubsan.
Fix this error by replacing the code with another function which adds 1 to a signed integer argument. This brings in ubsan to detect if it causes signed integer overflow. As the value of the argument cannot be statically determined, the new function is also immune to compiler warnings. Signed-off-by: Akihiko Odaki <akihiko.od...@daynix.com> --- configure | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/configure b/configure index 05bed4f4a1..cf72a4121f 100755 --- a/configure +++ b/configure @@ -1737,13 +1737,9 @@ if test "$sanitizers" = "yes" ; then # detect the static linking issue of ubsan, see also: # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84285 cat > $TMPC << EOF -#include <stdlib.h> -int main(void) { - void *tmp = malloc(10); - if (tmp != NULL) { - return *(int *)(tmp + 2); - } - return 1; +int main(int argc, char **argv) +{ + return argc + 1; } EOF if compile_prog "$CPU_CFLAGS -Werror -fsanitize=undefined" ""; then -- 2.40.0
