[PATCH] D89066: [Coroutine][Sema] Only tighten the suspend call temp lifetime for final awaiter

[Xun Li via Phabricator via cfe-commits]

lxfind added a comment.

In D89066#2324115 <https://reviews.llvm.org/D89066#2324115>, @junparser wrote:

> why we should not do this with normal await call?

To be honest, I don't know yet. My understanding of how expression cleanup and temp lifetime management is insufficient at the moment.
But first of all, without adding any cleanup expression here, I saw ASAN failures due to heap-use-after-free, because sometimes the frame have already been destroyed after the await_suspend call, and yet we are still writing into the frame due to unnecessarily cross-suspend lifetime. However, if I apply the cleanup to all await_suepend calls, it also causes ASAN failures as it's cleaning up data that's still alive.
So this patch is more of a temporary walkaround to stop bleeding without causing any trouble.
I plan to get back to this latter after I am done with the spilling/alloca issues.


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https://reviews.llvm.org/D89066