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

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 12/18/19 8:54 AM, Aleksandar Markovic wrote:
> 
> 
> On Tuesday, December 17, 2019, Philippe Mathieu-Daudé <philmd@redhat.com 
> <mailto:philmd@redhat.com>> wrote:
> 
>     GCC9 is confused by this comment when building with
>     CFLAG -Wimplicit-fallthrough=2:
> 
>        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
> 
>     Add the missing fall through comments.
> 
>     Fixes: 55d7bfe22
>     Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com
>     <mailto:philmd@redhat.com>>
>     ---
>     Cc: Olivier Danet <odanet@caramail.com <mailto:odanet@caramail.com>>
>     Cc: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk
>     <mailto:mark.cave-ayland@ilande.co.uk>>
>     ---
>       hw/display/tcx.c | 2 ++
>       1 file changed, 2 insertions(+)
> 
> 
> The content of the patch is fine, but the commit message is, I think, 
> inacurate: gcc is not confused at all, it does what it was told to.

You are correct, I'll update the comment.

> The title is fine.
> 
>     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
> 
>