[PATCH] D11670: [libcxx] Disable -Wnon-virtual-dtor warning in <locale>

[Eric Fiselier]

> If the base class has a protected non-virtual dtor and the derived class is marked final, this warning will not fire (because that interface will ensure no
> polymorphic destruction occurs). Would that be sufficient for your needs?

Oh, almost. I can't mark the derived class as final, but simply making
the base classes dtor protected prevents the warning. Thanks for the
information.

On Thu, Jul 30, 2015 at 11:16 PM, David Blaikie <dblaikie at gmail.com> wrote:
>
>
> On Thu, Jul 30, 2015 at 6:43 PM, Eric Fiselier <eric at efcs.ca> wrote:
>>
>> EricWF created this revision.
>> EricWF added a reviewer: mclow.lists.
>> EricWF added a subscriber: cfe-commits.
>>
>> Normally people won't see warnings in libc++ headers, but if they compile
>> with "-Wsystem-headers -Wnon-virtual-dtor" they will likely see issues in
>> <locale>.
>>
>> The struct `time_get` is specified as having a non-virtual protected
>> destructor but in the libc++ implementation `time_get` also has a
>> non-virtual base class with virtual methods.
>
>
> If the base class has a protected non-virtual dtor and the derived class is
> marked final, this warning will not fire (because that interface will ensure
> no polymorphic destruction occurs). Would that be sufficient for your needs?
>
>>
>> I don't believe this is a bug but instead a false positive.
>>
>>
>> http://reviews.llvm.org/D11670
>>
>> Files:
>>   include/__config
>>   include/locale
>>
>> Index: include/locale
>> ===================================================================
>> --- include/locale
>> +++ include/locale
>> @@ -1875,6 +1875,11 @@
>>      enum dateorder {no_order, dmy, mdy, ymd, ydm};
>>  };
>>
>> +#if __has_warning("-Wnon-virtual-dtor")
>> +#pragma clang diagnostic push
>> +#pragma clang diagnostic ignored "-Wnon-virtual-dtor"
>> +#endif
>> +
>>  template <class _CharT>
>>  class _LIBCPP_TYPE_VIS_ONLY __time_get_c_storage
>>  {
>> @@ -1890,6 +1895,10 @@
>>      virtual const string_type& __X() const;
>>  };
>>
>> +#if __has_warning("-Wnon-virtual-dtor")
>> +#pragma clang diagnostic pop
>> +#endif
>> +
>>  template <class _CharT, class _InputIterator =
>> istreambuf_iterator<_CharT> >
>>  class _LIBCPP_TYPE_VIS_ONLY time_get
>>      : public locale::facet,
>> Index: include/__config
>> ===================================================================
>> --- include/__config
>> +++ include/__config
>> @@ -45,6 +45,9 @@
>>  #ifndef __is_identifier
>>  #define __is_identifier(__x) 1
>>  #endif
>> +#ifndef __has_warning
>> +#define __has_warning(__x) 0
>> +#endif
>>
>>
>>  #ifdef __LITTLE_ENDIAN__
>>
>>
>>
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>