[PATCH] D135276: [AArch64] Add support for the SEH opcode for return address signing

[Martin Storsjö via Phabricator via llvm-commits]

mstorsjo added a comment.

In D135276#3837965 <https://reviews.llvm.org/D135276#3837965>, @efriedma wrote:

> As far as I know, there isn't any publicly released hardware running Windows that supports PAC.

Yeah, that's my understanding too.

(I kinda wondered that you might have access to such HW though, but if you have, you're of course also not allowed to comment on it. Although for this case, it wouldn't really reveal anything about the HW itself, other than that it exists, only about the Windows unwinder implementation.)

The reason I'm asking is for assessing the impact of the bug that we're currently willingly generated PAC instructions without matching unwind info. In https://code.videolan.org/videolan/vlc/-/merge_requests/2662 I suggested stopping using `-mbranch-protection=standard` for Windows targets (so current binaries won't start misbehaving on future HW) until this is implemented properly in LLVM. However, I'm getting counterarguments for preferring keeping the added security (even though no current HW benefits from it, only future HW), and that the lacking unwind info shouldn't have any notable runtime effect.


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https://reviews.llvm.org/D135276