Date: Sun, 4 Mar 2018 18:11:06 -0500 From: Shawn Webb <shawn.webb@hardenedbsd.org> To: freebsd-toolchain@freebsd.org Subject: Compiling libc with LTO Message-ID: <20180304231106.57dvw6psfpwnedbd@mutt-hbsd>
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[-- Attachment #1 --] Hey All, I'm working on Cross-DSO CFI support in HardenedBSD. I've noticed certain libraries do not like to be compiled with -flto, libc being one of them. I'm scratching my head a bit, but unsure where to go from here, so a little direction would be helpful. In the hardened/current/cross-dso-cfi feature branch of the hardenedBSD-playground repo[1], ld.lld, llvm-ar, llvm-nm, and llvm-objdump are the default ld, ar/ranlib, nm, and objdump respectively. The first step for Cross-DSO CFI support is compiling all shared and static libraries with LTO. I'm curious if this is a shortcoming of ld.lld and I should file a bug with the llvm project (if one's not already filed). I've heard that someone got FreeBSD compiled with LTO already, so I'm hoping to borrow some of their expertise. Here's a log of the build (warning: large file): https://gist.githubusercontent.com/anonymous/f8617d629fd054479142cc4b6de3581e/raw/b94579fac987556c01ae0aab7e2943d25d27bcc4/libc.log Essentially, the erroring lines are: /usr/obj/scratch/src/cross-dso-cfi/amd64.amd64/tmp/usr/bin/ld: error: swapcontext.pico: symbol swapcontext@@@FBSD_1.2 has undefined version @FBSD_1.2 /usr/obj/scratch/src/cross-dso-cfi/amd64.amd64/tmp/usr/bin/ld: error: openat.pico: symbol openat@@@FBSD_1.2 has undefined version @FBSD_1.2 /usr/obj/scratch/src/cross-dso-cfi/amd64.amd64/tmp/usr/bin/ld: error: setcontext.pico: symbol setcontext@@@FBSD_1.2 has undefined version @FBSD_1.2 [1]: https://github.com/HardenedBSD/hardenedBSD-playground/tree/hardened/current/cross-dso-cfi Thanks, -- Shawn Webb Cofounder and Security Engineer HardenedBSD Tor-ified Signal: +1 443-546-8752 GPG Key ID: 0x6A84658F52456EEE GPG Key Fingerprint: 2ABA B6BD EF6A F486 BE89 3D9E 6A84 658F 5245 6EEE [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEKrq2ve9q9Ia+iT2eaoRlj1JFbu4FAlqcfQUACgkQaoRlj1JF bu7gWA/8C+SpEA+Z8msBj3HKbUgeJNnQQokAHMqSnFJuU7lZshIT8oWJi1eRmdL9 7scq9PN3jmN/hziV5wObe4Kml+Rzl6+zMZJ/f6b6mX+7AOrSI403qtkAq7Qf/Uju 2G+gAh6mVh9iXgqBG4KzD7iUeFrwxaXAWEg8+MKgVMNUGvsqCmW94uzuD1T2xULO 3JtPTro20TjiPKSEIG1AHSptKFwIuPIntIIjKgjUpo2o1BTbgCWyxXc7HZv5RBC/ NxUdVMQLnd154AO0NIKcppkzxRPaEnwidBH6kjgkxbo1gH01iUrGrTiyqzThFqtC DMrhzj3zHCdPsbV/K73AdJnkSk8YrDVHtGBAaaVPOMASc8Cf4Jux1kPIJBsSUIzr NdcSHcS4zZbFTKjqbGqHMT+NH2UQ/53gohK4D38fFLujK5VxH6gAzoFiYvM5Pof5 +eHPEXh/DegLqGJGQj0vSgtMGj6HGOwsgKXO2AjF2gcbxrFNhC2RWhXKsuP7Gira Ak4NHuBBKS7xnhj2JCTtQtD766AXq0CifnibbPR/aZPYSROkXwvNiE8XbEhp+ABg Ri+X8s1zsaKWILbsGAdMWst6dLO9b/ahudStUF2vvrMxbTlGH+muCdEAA+gMKPNB skPWpqEEjJst4ft344uX14lbugliaqtoA2o3Ev4q6/XZkeQ+zQo= =TBui -----END PGP SIGNATURE-----home | help
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