[libcxx-commits] [libcxx] [libcxx] adds a size-based representation for `vector`'s unstable ABI (PR #155330)

[Louis Dionne via libcxx-commits]

https://github.com/ldionne commented:

Main remaining items:
- Remove `__zero_boundary_type` and `__zero_from_begin()`
- Don't zero-out moved-from layout in the layout move ctor
- Split `__set_boundary` into two functions and apply the changes that cascade from that (a few renames and the added `#ifdef` in `emplace_back`).

I think this can go in once these have been addressed!

https://github.com/llvm/llvm-project/pull/155330