[llvm] r295799 - Fix -Wcovered-switch-default.

[David Blaikie via llvm-commits]

On Thu, Feb 23, 2017 at 1:43 AM Sean Silva <chisophugis at gmail.com> wrote:

> On Wed, Feb 22, 2017 at 8:42 AM, David Blaikie <dblaikie at gmail.com> wrote:
>
> The unreachable outside a switch is usually in the case of a fully covered
> switch to address the way that other compilers conservatively assume that a
> covered switch may still be skipped (due to values that are not
> enumerators, but in the representable range of the enumeration). In this
> case, of a switch with a  default (not fully covered), unreachable in the
> default is OK/good I think.
>
>
> But then you don't get Clang's warning which assumes that the intent is to
> cover all enumerators, so you don't get the reminder to update this
> location if you add one.
>

Sure, but sometimes you don't want one - I don't think every switch over an
enum is/should be a fully covered one. At least that's my understanding at
the moment.

- Dave


>
> -- Sean Silva
>
>
>
> On Tue, Feb 21, 2017 at 11:01 PM Sean Silva via llvm-commits <
> llvm-commits at lists.llvm.org> wrote:
>
> Usually we put the unreachable outside the switch:
>
>
> http://llvm.org/docs/CodingStandards.html#don-t-use-default-labels-in-fully-covered-switches-over-enumerations
>
> On Tue, Feb 21, 2017 at 5:01 PM, Rui Ueyama via llvm-commits <
> llvm-commits at lists.llvm.org> wrote:
>
> Author: ruiu
> Date: Tue Feb 21 19:01:45 2017
> New Revision: 295799
>
> URL: http://llvm.org/viewvc/llvm-project?rev=295799&view=rev
> Log:
> Fix -Wcovered-switch-default.
>
> Modified:
>     llvm/trunk/lib/Object/ArchiveWriter.cpp
>
> Modified: llvm/trunk/lib/Object/ArchiveWriter.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Object/ArchiveWriter.cpp?rev=295799&r1=295798&r2=295799&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Object/ArchiveWriter.cpp (original)
> +++ llvm/trunk/lib/Object/ArchiveWriter.cpp Tue Feb 21 19:01:45 2017
> @@ -129,9 +129,7 @@ static bool isBSDLike(object::Archive::K
>    case object::Archive::K_BSD:
>    case object::Archive::K_DARWIN:
>      return true;
> -  case object::Archive::K_MIPS64:
> -  case object::Archive::K_DARWIN64:
> -  case object::Archive::K_COFF:
> +  default:
>      llvm_unreachable("not supported for writting");
>    }
>  }
>
>
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