[llvm-dev] LTO, ifuncs, and lld
Shawn Webb via llvm-dev
llvm-dev at lists.llvm.org
Wed Nov 28 17:34:59 PST 2018
Here you go!
Cofounder and Security Engineer
Tor-ified Signal: +1 443-546-8752
Tor+XMPP+OTR: lattera at is.a.hacker.sx
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On Wed, Nov 28, 2018 at 05:30:57PM -0800, Peter Collingbourne wrote:
> 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?
> 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
> > Tor-ified Signal: +1 443-546-8752
> > Tor+XMPP+OTR: lattera at is.a.hacker.sx
> > GPG Key ID: 0x6A84658F52456EEE
> > GPG Key Fingerprint: 2ABA B6BD EF6A F486 BE89 3D9E 6A84 658F 5245 6EEE
> > _______________________________________________
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> > llvm-dev at lists.llvm.org
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