> Am 15.11.2025 um 11:06 schrieb Jakub Jelinek <[email protected]>:
>
> Hi!
>
> Here is a fix for the test I've talked about today in the libsanitizer
> update mail.
>
> The test relied on a coming before b coming before c, all with 32 byte
> distances, but gcc can actually emit them in the exact opposite order
> or some other one.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ok
Richard
> 2025-11-14 Jakub Jelinek <[email protected]>
>
> * c-c++-common/asan/asan-stack-small.c (pa, pb, pc): Make these
> vars volatile.
> (uintptr_t): New typedef.
> (main): Use access of b using pa pointer with offset depending on
> how exactly the 3 variables are laid out in the frame.
>
> --- gcc/testsuite/c-c++-common/asan/asan-stack-small.c.jj 2020-01-14
> 20:02:46.644611916 +0100
> +++ gcc/testsuite/c-c++-common/asan/asan-stack-small.c 2025-11-14
> 12:14:46.078840290 +0100
> @@ -1,8 +1,9 @@
> /* { dg-do run } */
>
> -char *pa;
> -char *pb;
> -char *pc;
> +char *volatile pa;
> +char *volatile pb;
> +char *volatile pc;
> +typedef __UINTPTR_TYPE__ uintptr_t;
>
> void access (volatile char *ptr)
> {
> @@ -22,7 +23,14 @@ int main (int argc, char **argv)
> access (pb);
> access (pc);
> // access 'b' here
> - access (pa + 32);
> + if ((uintptr_t) pb == (uintptr_t) pa + 32)
> + access (pa + 32);
> + else if ((uintptr_t) pb == (uintptr_t) pa - 32)
> + access (pa - 32);
> + else if ((uintptr_t) pb == (uintptr_t) pa + 64)
> + access (pa + 64);
> + else if ((uintptr_t) pb == (uintptr_t) pa - 64)
> + access (pa - 64);
>
> return 0;
> }
>
> Jakub
>
