Re: [PATCH 8/9] target/ppc: silence the compiler warnings

[Philippe Mathieu-Daudé]

On 10/28/20 5:18 AM, Chen Qun wrote:
> When using -Wimplicit-fallthrough in our CFLAGS, the compiler showed warning:
> target/ppc/mmu_helper.c: In function ‘dump_mmu’:
> target/ppc/mmu_helper.c:1351:12: warning: this statement may fall through 
> [-Wimplicit-fallthrough=]
>  1351 |         if (ppc64_v3_radix(env_archcpu(env))) {
>       |            ^
> target/ppc/mmu_helper.c:1358:5: note: here
>  1358 |     default:
>       |     ^~~~~~~
> 
> Add the corresponding "fall through" comment to fix it.
> 
> Reported-by: Euler Robot <euler.robot@huawei.com>
> Signed-off-by: Chen Qun <kuhn.chenqun@huawei.com>
> ---
> Cc: David Gibson <david@gibson.dropbear.id.au>
> ---
>  target/ppc/mmu_helper.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/target/ppc/mmu_helper.c b/target/ppc/mmu_helper.c
> index 8972714775..51749b62df 100644
> --- a/target/ppc/mmu_helper.c
> +++ b/target/ppc/mmu_helper.c
> @@ -1355,6 +1355,7 @@ void dump_mmu(CPUPPCState *env)
>              break;
>          }
>  #endif
> +        /* fall through */

I'm surprise the compiler emit a warning for missing comment,
but don't emit one for superfluous and confusing ones (when
building a ppc32-only target). You'd need to put this before
the #endif.

But instead of this band-aid to silent warning, replace the
TODO by a LOG_UNIMP call, and add a break before the #endif.

>      default:
>          qemu_log_mask(LOG_UNIMP, "%s: unimplemented\n", __func__);
>      }
>