Re: [PATCH v4 08/11] xen/compiler: import 'fallthrough' keyword from linux

[Jan Beulich <jbeulich@xxxxxxxx>]

On 08.01.2021 15:46, Rahul Singh wrote:
> -Wimplicit-fallthrough warns when a switch case falls through. Warning
> can be suppress by either adding a /* fallthrough */ comment, or by
> using a null statement: __attribute__ ((fallthrough))

Why is the comment variant (which we use in many places already,
albeit with varying wording) not the route of choice?

> Define the pseudo keyword 'fallthrough' for the ability to convert the
> various case block /* fallthrough */ style comments to null statement
> "__attribute__((__fallthrough__))"
> 
> In C mode, GCC supports the __fallthrough__ attribute since 7.1,
> the same time the warning and the comment parsing were introduced.
> 
> fallthrough devolves to an empty "do {} while (0)" if the compiler
> version (any version less than gcc 7) does not support the attribute.

What about Coverity? It would be nice if we wouldn't need to add
two separate constructs everywhere to make both compiler and static
code checker happy.

Jan