Momchil Velikov via llvm-dev
2021-Dec-09 14:56 UTC
[llvm-dev] [RFC] Asynchronous unwind tables attribute
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 andexplicitly 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 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20211209/97b3f805/attachment.html>
Eric Christopher via llvm-dev
2021-Dec-11 00:47 UTC
[llvm-dev] [RFC] Asynchronous unwind tables attribute
Ultimately I think I'd like to know why you think you should do this, hence the request for use cases :) Thanks! -eric On Thu, Dec 9, 2021 at 6:57 AM Momchil Velikov <momchil.velikov at gmail.com> wrote:> 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 > >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20211210/44741e69/attachment.html>