[libcxx-commits] [PATCH] D112869: [libc++] Implement P2186R2 (Remove Garbage Collection)

[Louis Dionne via Phabricator via libcxx-commits]

ldionne requested changes to this revision.
ldionne added a comment.
This revision now requires changes to proceed.

At first sight, I'm OK with this removal. I, too, can't imagine anyone relying on that code. However, I think we should still keep those symbols around because we have a hard policy of never removing symbols exported from the dylib (except in special circumstances where the symbol is also defined in any TU that uses the said function, like a function template that would end up being exported from the dylib by mistake).

Long story short, I would create a `legacy_pointer_safety.cpp` file and shove `declare_reachable` & friends in it. I would add a comment explaining that we don't ship that feature anymore, but we're still providing the symbols for strict backwards ABI compatibility.

This way, if someone has compiled code that (for some probably bad) reason relied on those symbols, their program will keep working when libc++ is updated from under their feet (e.g. when you update your OS on any platform that uses libc++). If someone used to rely on those and tries to compile their code against a new libc++, they will have to get rid of those references because the library won't provide the declarations anymore - but I think it's reasonable to request some minimal action if folks are recompiling their code. Finally, this solution is very low maintenance for us.


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https://reviews.llvm.org/D112869