Hello Peter, On Mon, 16 Oct 2023, 17:13 Peter Maydell, <peter.mayd...@linaro.org> wrote:
> On Fri, 13 Oct 2023 at 13:42, Markus Armbruster <arm...@redhat.com> wrote: > > > > Emmanouil Pitsidianakis <manos.pitsidiana...@linaro.org> writes: > > > > > Hello, > > > > > > This RFC is inspired by the kernel's move to -Wimplicit-fallthrough=3 > > > back in 2019.[0] > > > We take one step (or two) further by increasing it to 5 which rejects > > > fall through comments and requires an attribute statement. > > > > > > [0]: > > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a035d552a93b > > > > > > The line differences are not many, but they spread all over different > > > subsystems, architectures and devices. An attempt has been made to > split > > > them in cohesive patches to aid post-RFC review. Part of the RFC is to > > > determine whether these patch divisions needs improvement. > > > > > > Main questions this RFC poses > > > ============================= > > > > > > - Is this change desirable and net-positive. > > > > Unwanted fallthrough is an easy mistake to make, and > > -Wimplicit-fallthrough=N helps avoid it. The question is how far up we > > need to push N. Right now we're at N=2. Has unwanted fallthrough been > > a problem? > > Mmm, this is my opinion I think. We have a mechanism for > catching "forgot the 'break'" already (our =2 setting) and > a way to say "intentional" in a fairly natural way (add the > comment). Does pushing N up any further gain us anything > except a load of churn? > > Also, the compiler is not the only thing that processes our > code: Coverity also looks for "unexpected fallthrough" issues, > so if we wanted to switch away from our current practice we > should check whether what we're switching to is an idiom > that Coverity recognises. > It is a code style change as the cover letter mentions, it's not related to the static analysis itself. -- Manos >
