[libcxx-commits] [PATCH] D146190: Fix EBO on std::optional and std::variant when targeting the MSVC ABI

[Mark de Wever via Phabricator via libcxx-commits]

Mordante added a comment.

Thanks for the patch!

I'm not really fond of declaring the MSVC ABI as unstable. If there is no other way, please add this information in the commit message. That way we can find back why it was decided to declare the ABI on a platform as unstable.



================
Comment at: libcxx/include/optional:641
 template <class _Tp>
-class optional
+class _LIBCPP_DECLSPEC_EMPTY_BASES optional
     : private __optional_move_assign_base<_Tp>
----------------
Why not guard this attribute with a `_LIBCPP_ABI_FOO_FLAG` instead of breaking the ABI unconditionally?


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D146190/new/

https://reviews.llvm.org/D146190