[libcxx-commits] [PATCH] D120064: Fix EBO on std::optional and std::variant when targeting the MSVC ABI

[Louis Dionne via Phabricator via libcxx-commits]

ldionne requested changes to this revision.
ldionne added a subscriber: mstorsjo.
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In D120064#3329840 <https://reviews.llvm.org/D120064#3329840>, @jdoerrie wrote:

> Hi both, PTAL. I was surprised to find out that both `std::variant<int>` and `std::optional<int>` have a sizeof 12 in my environment, this is my attempt to fix it. Please do let me know if there are other places I need to change, or how I would write a test to prevent future regressions.

This is an ABI break on Windows, pinging @mstorsjo.

Regarding writing a test, you can add one in the appropriate subdirectory of `libcxx/test/libcxx` so we only check the property when testing libc++ itself, not other standard library implementations.


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  https://reviews.llvm.org/D120064/new/

https://reviews.llvm.org/D120064