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    SubjectRe: [PATCH 000/141] Fix fall-through warnings for Clang
    On Fri, 20 Nov 2020 11:30:40 -0800 Kees Cook wrote:
    > On Fri, Nov 20, 2020 at 10:53:44AM -0800, Jakub Kicinski wrote:
    > > On Fri, 20 Nov 2020 12:21:39 -0600 Gustavo A. R. Silva wrote:
    > > > This series aims to fix almost all remaining fall-through warnings in
    > > > order to enable -Wimplicit-fallthrough for Clang.
    > > >
    > > > In preparation to enable -Wimplicit-fallthrough for Clang, explicitly
    > > > add multiple break/goto/return/fallthrough statements instead of just
    > > > letting the code fall through to the next case.
    > > >
    > > > Notice that in order to enable -Wimplicit-fallthrough for Clang, this
    > > > change[1] is meant to be reverted at some point. So, this patch helps
    > > > to move in that direction.
    > > >
    > > > Something important to mention is that there is currently a discrepancy
    > > > between GCC and Clang when dealing with switch fall-through to empty case
    > > > statements or to cases that only contain a break/continue/return
    > > > statement[2][3][4].
    > >
    > > Are we sure we want to make this change? Was it discussed before?
    > >
    > > Are there any bugs Clangs puritanical definition of fallthrough helped
    > > find?
    > >
    > > IMVHO compiler warnings are supposed to warn about issues that could
    > > be bugs. Falling through to default: break; can hardly be a bug?!
    >
    > It's certainly a place where the intent is not always clear. I think
    > this makes all the cases unambiguous, and doesn't impact the machine
    > code, since the compiler will happily optimize away any behavioral
    > redundancy.

    If none of the 140 patches here fix a real bug, and there is no change
    to machine code then it sounds to me like a W=2 kind of a warning.

    I think clang is just being annoying here, but if I'm the only one who
    feels this way chances are I'm wrong :)

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