[PATCH] D72897: List implicit operator== after implicit destructors in a vtable.

[Richard Smith - zygoloid via Phabricator via cfe-commits]

rsmith added a comment.

In D72897#1825791 <https://reviews.llvm.org/D72897#1825791>, @rjmccall wrote:

> I know that Sema used to have a lot of issues with implicitly declaring special members, but I also know that that was bound up with how we tracked special state for the class, and that code has changed a lot.   If you feel that that's an unlikely problem now, and you're comfortable with potentially having to generate implicit declarations of special members in different orders to satisfy different ABIs, I can accept this approach.


I'm not particularly overjoyed by having an ABI decision determined by the order in which Sema chooses to implicitly declare these members. I think it's unlikely to have stability problems (we explicitly force declaration of virtual implicit members at the end of the class before they can have been lazily declared), but avoiding a reliance on Sema's behavior would be nice. It'd be hard to avoid relying on `Sema` getting the order of implicit `operator==` functions right, though, as I don't think we want vtable layout to be responsible for figuring out the correspondence between implicit `operator==` functions and defaulted `operator<=>` functions. Please take a look at this alternative approach and see what you think.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D72897/new/

https://reviews.llvm.org/D72897