On Thu, 2 May 2024 at 08:42, Philippe Mathieu-Daudé <phi...@linaro.org> wrote:
>
> Check the function index is not negative and use an unsigned
> variable to avoid the following warning with GCC 13.2.0:
>
> [666/5358] Compiling C object libcommon.fa.p/hw_input_tsc2005.c.o
> hw/input/tsc2005.c: In function 'tsc2005_timer_tick':
> hw/input/tsc2005.c:416:26: warning: array subscript has type 'char'
> [-Wchar-subscripts]
> 416 | s->dav |= mode_regs[s->function];
> | ~^~~~~~~~~~
>
> Signed-off-by: Philippe Mathieu-Daudé <phi...@linaro.org>
> ---
> hw/input/tsc2005.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/hw/input/tsc2005.c b/hw/input/tsc2005.c
> index 941f163d36..fa93eb5d25 100644
> --- a/hw/input/tsc2005.c
> +++ b/hw/input/tsc2005.c
> @@ -406,6 +406,7 @@ uint32_t tsc2005_txrx(void *opaque, uint32_t value, int
> len)
> static void tsc2005_timer_tick(void *opaque)
> {
> TSC2005State *s = opaque;
> + unsigned func_idx;
>
> /* Timer ticked -- a set of conversions has been finished. */
>
> @@ -413,7 +414,9 @@ static void tsc2005_timer_tick(void *opaque)
> return;
>
> s->busy = false;
> - s->dav |= mode_regs[s->function];
> + assert(s->function >= 0);
> + func_idx = s->function;
> + s->dav |= mode_regs[func_idx];
> s->function = -1;
> tsc2005_pin_update(s);
> }
This code is in a deprecated device, but it makes sense to
avoid the compiler warning in the meantime. (I'm curious why this
only comes up now, since I thought this warning had been around
for a while. Maybe gcc 13 is applying it in a wider range of
situations.)
If we're going to assert I think we might as well catch
array overruns in both directions:
unsigned int function = s->function;
assert(function < ARRAY_SIZE(mode_regs);
s->dav |= mode_regs[function];
thanks
-- PMM
