[libcxx] r296561 - Fix PR32097 - is_abstract doesn't work on class templates.

[Eric Fiselier via cfe-commits]

4.0.1 it is. Thanks Hans!

/Eric

On Wed, Mar 1, 2017 at 10:08 AM, Hans Wennborg <hans at chromium.org> wrote:

> We're at the "should have tagged 'final' days ago" stage :-)
>
> Since it's not a regression, I would prefer not to merge it unless you
> feel super strongly about it.
>
> Sounds like a good candidate for 4.0.1 (tracking bug is PR32061).
>
> Thanks,
> Hans
>
> On Wed, Mar 1, 2017 at 1:36 AM, Eric Fiselier <eric at efcs.ca> wrote:
> > @Hans Where are we in the release process? I would like to merge this
> into
> > 4.0.
> >
> > Although it's not a regression, it is a significant bug. This patch fixes
> > the bug by
> > forwarding to a compiler builtin, which is strictly better than what we
> > have. I'm
> > confident this patch is safe.
> >
> > /Eric
> >
> > On Tue, Feb 28, 2017 at 6:27 PM, Eric Fiselier via cfe-commits
> > <cfe-commits at lists.llvm.org> wrote:
> >>
> >> Author: ericwf
> >> Date: Tue Feb 28 19:27:14 2017
> >> New Revision: 296561
> >>
> >> URL: http://llvm.org/viewvc/llvm-project?rev=296561&view=rev
> >> Log:
> >> Fix PR32097 - is_abstract doesn't work on class templates.
> >>
> >> This patch fixes llvm.org/PR32097 by using the __is_abstract
> >> builtin type-trait instead of the previous library-only implementation.
> >>
> >> All supported compilers provide this trait. I've tested as far
> >> back as Clang 3.2, GCC 4.6 and MSVC trunk.
> >>
> >> Modified:
> >>     libcxx/trunk/include/type_traits
> >>
> >> libcxx/trunk/test/std/utilities/meta/meta.unary/
> meta.unary.prop/is_abstract.pass.cpp
> >>
> >> Modified: libcxx/trunk/include/type_traits
> >> URL:
> >> http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/
> type_traits?rev=296561&r1=296560&r2=296561&view=diff
> >>
> >> ============================================================
> ==================
> >> --- libcxx/trunk/include/type_traits (original)
> >> +++ libcxx/trunk/include/type_traits Tue Feb 28 19:27:14 2017
> >> @@ -1297,18 +1297,8 @@ template <class _Tp> using decay_t = typ
> >>
> >>  // is_abstract
> >>
> >> -namespace __is_abstract_imp
> >> -{
> >> -template <class _Tp> char  __test(_Tp (*)[1]);
> >> -template <class _Tp> __two __test(...);
> >> -}
> >> -
> >> -template <class _Tp, bool = is_class<_Tp>::value>
> >> -struct __libcpp_abstract : public integral_constant<bool,
> >> sizeof(__is_abstract_imp::__test<_Tp>(0)) != 1> {};
> >> -
> >> -template <class _Tp> struct __libcpp_abstract<_Tp, false> : public
> >> false_type {};
> >> -
> >> -template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_abstract : public
> >> __libcpp_abstract<_Tp> {};
> >> +template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_abstract
> >> +    : public integral_constant<bool, __is_abstract(_Tp)> {};
> >>
> >>  #if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_
> VARIABLE_TEMPLATES)
> >>  template <class _Tp> _LIBCPP_CONSTEXPR bool is_abstract_v
> >>
> >> Modified:
> >> libcxx/trunk/test/std/utilities/meta/meta.unary/
> meta.unary.prop/is_abstract.pass.cpp
> >> URL:
> >> http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/
> utilities/meta/meta.unary/meta.unary.prop/is_abstract.
> pass.cpp?rev=296561&r1=296560&r2=296561&view=diff
> >>
> >> ============================================================
> ==================
> >> ---
> >> libcxx/trunk/test/std/utilities/meta/meta.unary/
> meta.unary.prop/is_abstract.pass.cpp
> >> (original)
> >> +++
> >> libcxx/trunk/test/std/utilities/meta/meta.unary/
> meta.unary.prop/is_abstract.pass.cpp
> >> Tue Feb 28 19:27:14 2017
> >> @@ -65,6 +65,14 @@ class Abstract
> >>      virtual ~Abstract() = 0;
> >>  };
> >>
> >> +template <class>
> >> +struct AbstractTemplate {
> >> +  virtual void test() = 0;
> >> +};
> >> +
> >> +template <>
> >> +struct AbstractTemplate<double> {};
> >> +
> >>  int main()
> >>  {
> >>      test_is_not_abstract<void>();
> >> @@ -81,4 +89,6 @@ int main()
> >>      test_is_not_abstract<NotEmpty>();
> >>
> >>      test_is_abstract<Abstract>();
> >> +    test_is_abstract<AbstractTemplate<int> >();
> >> +    test_is_not_abstract<AbstractTemplate<double> >();
> >>  }
> >>
> >>
> >> _______________________________________________
> >> cfe-commits mailing list
> >> cfe-commits at lists.llvm.org
> >> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
> >
> >
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20170301/33469205/attachment.html>