[llvm-dev] LTO, ifuncs, and lld

[Peter Collingbourne via llvm-dev]

Hi Shawn,

Can you please create a reproducer tarball (using ld.lld --reproduce) so
that we don't need to install HardenedBSD in order to reproduce?

Peter

On Wed, Nov 28, 2018 at 5:16 PM Shawn Webb via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

> Hey LLVM folks,
>
> I've run into an interesting assertion. In one of HardenedBSD's
> feature branches, we're working on integration llvm's Cross-DSO CFI
> implementation. Using Cross-DSO CFI requires building libs with LTO,
> which causes clang to emit LLVM IR intermediate object files rather
> than ELF intermediate object files.
>
> I've found that with lld, attempting to link LLVM IR intermediate
> object files hits an assert in lld. I've created a reproduction test
> case in this tiny little repo: https://github.com/lattera/ifunc_repro
>
> The assertion I hit is detailed in the commit message of the initial
> commit:
>
> https://github.com/lattera/ifunc_repro/commit/0be98f9e81a1c91e80b135da6bb8d073d7a0c6f7
>
> HardenedBSD's Cross-DSO CFI feature branch uses clang/llvm/lld 7.0.1.
> I'm more than happy to test out patches to help address this issue.
>
> Please let me know if you have any questions, comments, or concerns.
>
> Thanks,
>
> --
> Shawn Webb
> Cofounder and Security Engineer
> HardenedBSD
>
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-- 
-- 
Peter
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