[PATCH] D99417: [AArch64][v8.5A] Add BTI to all function starts

[Pablo Barrio via Phabricator via llvm-commits]

pbarrio added a comment.

> For patchable functions are there any other cases where we wouldn't generate a BTI at the start of the function? If there is we may be alter the test so that it is still checking that the nop is still inserted. If there is no way to avoid a BTI then we may have to alter the expected result and the comment.
>
> I've dug up https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92424 and https://reviews.llvm.org/D72215 for context.

Thanks for the context! I don't think there is a way to generate a function without an initial landing pad ATM. The BTI placement pass will add a landing pad at the beginning of any BB that is the start of a function.

>From a quick look at that GCC bug report, I think we should be fine now: the landing pads are place at the right point. If, at some point, the behaviour of LLVM changes again, I've reinstated the test that I initially removed, and hopefully it will shout.


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https://reviews.llvm.org/D99417