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

[David Blaikie]

On Thu, Jul 30, 2015 at 9:58 PM, Eric Fiselier <eric at efcs.ca> wrote:

> > 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.
>

Awesome :)


>
> 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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> >>
> >
>
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