Re: [PATCH v2 2/6] hw/display/tcx: Add missing fall through comments

[Aleksandar Markovic <aleksandar.m.mail@gmail.com>]

On Wed, Dec 18, 2019 at 8:26 PM Philippe Mathieu-Daudé
<philmd@redhat.com> wrote:
>
> When building with GCC9 using CFLAG -Wimplicit-fallthrough=2 we get:
>
>   hw/display/tcx.c: In function ‘tcx_dac_writel’:
>   hw/display/tcx.c:453:26: error: this statement may fall through [-Werror=implicit-fallthrough=]
>     453 |             s->dac_index = (s->dac_index + 1) & 0xff; /* Index autoincrement */
>         |             ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
>   hw/display/tcx.c:454:9: note: here
>     454 |         default:
>         |         ^~~~~~~
>   hw/display/tcx.c: In function ‘tcx_dac_readl’:
>   hw/display/tcx.c:412:22: error: this statement may fall through [-Werror=implicit-fallthrough=]
>     412 |         s->dac_index = (s->dac_index + 1) & 0xff; /* Index autoincrement */
>         |         ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
>   hw/display/tcx.c:413:5: note: here
>     413 |     default:
>         |     ^~~~~~~
>   cc1: all warnings being treated as errors
>
> Give a hint to GCC by adding the missing fall through comments.
>
> Fixes: 55d7bfe22
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
> v2: Reword the description (Aleksandar)
>

Reviewed-by: Aleksandar Markovic <amarkovic@wavecomp.com>

> Cc: Aleksandar Markovic <aleksandar.m.mail@gmail.com>
> Cc: Olivier Danet <odanet@caramail.com>
> Cc: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> ---
>  hw/display/tcx.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/hw/display/tcx.c b/hw/display/tcx.c
> index 14e829d3fa..abbeb30284 100644
> --- a/hw/display/tcx.c
> +++ b/hw/display/tcx.c
> @@ -410,6 +410,7 @@ static uint64_t tcx_dac_readl(void *opaque, hwaddr addr,
>      case 2:
>          val = s->b[s->dac_index] << 24;
>          s->dac_index = (s->dac_index + 1) & 0xff; /* Index autoincrement */
> +        /* fall through */
>      default:
>          s->dac_state = 0;
>          break;
> @@ -451,6 +452,7 @@ static void tcx_dac_writel(void *opaque, hwaddr addr, uint64_t val,
>              s->b[index] = val >> 24;
>              update_palette_entries(s, index, index + 1);
>              s->dac_index = (s->dac_index + 1) & 0xff; /* Index autoincrement */
> +            /* fall through */
>          default:
>              s->dac_state = 0;
>              break;
> --
> 2.21.0
>