[llvm-dev] [RFC] Asynchronous unwind tables attribute

[Momchil Velikov via llvm-dev]

On Wed, 24 Nov 2021 at 18:18, Eric Christopher <echristo at gmail.com> wrote:
>
> Hi Momchil,
>
> So, I think to elaborate from the thread you're looking at separating out:
>
> no tables,
> exception handling,
> instruction level unwind accuracy
>
> for unwind tables? Some examples of cases you expect to work and
explicitly not work in each of these would be fairly motivating. Going down
the use cases for each.

Not really. What I'm looking for is to convey the value of the CodeGen
option `UnwindTables` from clang to LLVM.

         | nounwind 0  |  nounwind 1
----------+-------------+--------------
uwtable 0 | <full,no>   |  <no,no>
----------+-------------+--------------
uwtable 1 | <full,no>   |  <full,no>
----------+-------------+--------------
uwtable 2 | <full,full> |  <full,full>


Lacking that, a backend can choose to generate unwind tables either  according
to the
second or the third rows, but a user has no control of it. As different
kinds of unwind
tables have different functionality and trade-offs, that should be
something under
user control.

~chill
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