On Wed, 17 Jul 2024 at 13:19, Josef Wolf <jw@xxxxxxxxxxxxx> wrote:
>
> Hallo,
>
> just upgraded my crossgcc-toolchain to gcc-1-14-0.
>
> Given this code snippet:
>
> #define MG 32
> static unsigned char a[MG] = {0};
>
> void init_login (void)
> {
> int i;
>
> for (i=0; i<MG; i++) {
> a[i] = 1;
> }
> }
>
> IMHO, this code should not access index 32 of the array, because
> the for loop should terminate.
>
> Thus, following warning is completely unexpected to me:
>
> m68k-unknown-elf-gcc -ansi -pedantic -Wall -Wcast-align -Wstrict-prototypes -Wmissing-prototypes -std=c99 -Wnull-dereference -g -O3 -fno-toplevel-reorder -mcpu32 -ffreestanding -c -o login.o login.c
> login.c: In function 'init_login':
> login.c:2909:22: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]
> 2909 | a[i] = 1;
> | ~~~~~^~~
> login.c:2899:22: note: at offset 32 into destination object 'a' of size 32
> 2899 | static unsigned char a[MG] = {0};
> | ^
>
> Opinions?
-Wstringop-overflow is broken by design.
This is one of the worst examples I've seen though.
