On Mon, 2020-10-19 at 12:42 -0700, Nick Desaulniers wrote: > On Sat, Oct 17, 2020 at 10:43 PM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > On Sat, Oct 17, 2020 at 09:09:28AM -0700, trix@xxxxxxxxxx wrote: > > > From: Tom Rix <trix@xxxxxxxxxx> > > > > > > This is a upcoming change to clean up a new warning treewide. > > > I am wondering if the change could be one mega patch (see below) or > > > normal patch per file about 100 patches or somewhere half way by collecting > > > early acks. > > > > Please break it up into one-patch-per-subsystem, like normal, and get it > > merged that way. > > > > Sending us a patch, without even a diffstat to review, isn't going to > > get you very far... > > Tom, > If you're able to automate this cleanup, I suggest checking in a > script that can be run on a directory. Then for each subsystem you > can say in your commit "I ran scripts/fix_whatever.py on this subdir." > Then others can help you drive the tree wide cleanup. Then we can > enable -Wunreachable-code-break either by default, or W=2 right now > might be a good idea. > > Ah, George (gbiv@, cc'ed), did an analysis recently of > `-Wunreachable-code-loop-increment`, `-Wunreachable-code-break`, and > `-Wunreachable-code-return` for Android userspace. From the review: > ``` > Spoilers: of these, it seems useful to turn on > -Wunreachable-code-loop-increment and -Wunreachable-code-return by > default for Android > ... > While these conventions about always having break arguably became > obsolete when we enabled -Wfallthrough, my sample turned up zero > potential bugs caught by this warning, and we'd need to put a lot of > effort into getting a clean tree. So this warning doesn't seem to be > worth it. > ``` > Looks like there's an order of magnitude of `-Wunreachable-code-break` > than the other two. > > We probably should add all 3 to W=2 builds (wrapped in cc-option). > I've filed https://github.com/ClangBuiltLinux/linux/issues/1180 to > follow up on. I suggest using W=1 as people that are doing cleanups generally use that and not W=123 or any other style. Every other use of W= is still quite noisy and these code warnings are relatively trivially to fix up.
