[cfe-commits] r165091 - /cfe/trunk/lib/AST/MicrosoftMangle.cpp

[Aaron Ballman]

On Wed, Oct 3, 2012 at 8:16 AM, Nico Weber <thakis at chromium.org> wrote:
> On Wed, Oct 3, 2012 at 9:05 PM, Aaron Ballman <aaron at aaronballman.com> wrote:
>> On Wed, Oct 3, 2012 at 2:12 AM, Nico Weber <nicolasweber at gmx.de> wrote:
>>> Author: nico
>>> Date: Wed Oct  3 01:12:27 2012
>>> New Revision: 165091
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=165091&view=rev
>>> Log:
>>> Replace a default: with an explicit list of cases. No functionality change.
>>>
>>> Modified:
>>>     cfe/trunk/lib/AST/MicrosoftMangle.cpp
>>>
>>> Modified: cfe/trunk/lib/AST/MicrosoftMangle.cpp
>>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/MicrosoftMangle.cpp?rev=165091&r1=165090&r2=165091&view=diff
>>> ==============================================================================
>>> --- cfe/trunk/lib/AST/MicrosoftMangle.cpp (original)
>>> +++ cfe/trunk/lib/AST/MicrosoftMangle.cpp Wed Oct  3 01:12:27 2012
>>> @@ -810,7 +810,12 @@
>>>          break;
>>>        }
>>>        /* fallthrough */
>>> -    } default: {
>>> +    }
>>> +    case TemplateArgument::Template:
>>> +    case TemplateArgument::TemplateExpansion:
>>> +    case TemplateArgument::Declaration:
>>> +    case TemplateArgument::NullPtr:
>>> +    case TemplateArgument::Pack: {
>>>        // Issue a diagnostic.
>>>        DiagnosticsEngine &Diags = Context.getDiags();
>>>        unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
>>
>> Now if another value is added to the list, it will silently fail; is
>> this acceptable?  I would feel more comfortable if there was still a
>> default case that would be marked as unreachable.
>
> It won't silently fail, clang will warn that a enum case isn't handled.

Clang will, but not all compilers will.  MSVC doesn't warn on that
situation, for instance.  Marking default with llvm_unreachable solves
that by ensuring there's no warning, and by complaining loudly if the
default is ever hit (so you can't ignore it).

~Aaron