clang-musl-overlay / gentoo-patchset

Patchset containing fixes for a working LLVM + Musl Gentoo installation

clang-musl overlay

Overlay containing experimental clang-musl profile and related ebuilds.

Prequisite

• A working gentoo/musl system.
• Self-hosted clang compiler, with the default-libcxx USE flag enabled.
• Some knowledge of compilers, linkers and gentoo's package manager portage.

Installation

• Create a new file /etc/portage/repos.conf/clang-musl.conf with the following contents:

[clang-musl]
sync-uri = https://github.com/clang-musl-overlay/clang-musl-overlay.git
sync-type = git
location = /var/db/repos/clang-musl
sync-depth = 1

• Sync this new repo using emaint sync -r clang-musl or emerge --sync

Profiles

clang-musl overlay provides clang-musl and clang-musl/hardened profiles

Switching to clang-musl profile:

• Use eselect to list all the profiles. Note the new profile and select the profile

eselect profile set --force <profile>

Setting clang and llvm binutils as default

• Switch to clang-musl profile
• Unmerge gcc, binutils and their dependencies with a --depclean. emerge -c
• Merge sys-devel/llvm-conf. This should automatically set latest llvm/clang as your default toolchain.
  • Or you can run llvm-conf --enable-native-links --enable-clang-wrappers --enable-binutils-wrappers llvm-14
• Now you can run emerge -1euDN @world to rebuild everything with clang/llvm.

Issues

• Programs may fail to build when using clang. There are already patches for known issues at gentoo-patchset.
• LTO and other optimization may lead to build issues for some pkgs. Please report if you find any issue.

gentoo-patchset's Issues

Kernel 6.x - missed config CC_OPTIMIZE_FOR_PERFORMANCE_O3

Hello there!
In Kernel 6.x is missed value:
config CC_OPTIMIZE_FOR_PERFORMANCE_O3
Can You please look over and provide fix (patch) for enable -O3 level?
Thanks!

Package “sys-libs/db” failing to build correctly with lld linker

The sys-libs/db package fails to build correctly with the lldlinker. To fix this issue, we need to remove or comment out "append-ldflags -Wl,--default-symver" from the ebuild, as well as removing "tc-force-bfd" and "binutils" as a dependency in the ebuild. However, even if db builds with lld under these conditions, it still makes many references to binutils in the result. This can lead to errors in runtime, so manual patching is required.

Issue crossposted to "clang-musl-overlay"