Zld 1.3.3

[rgnns]

Motivation for this change

zld is a faster linker than Apple's linker.

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• 21.11 Release Notes (or backporting 21.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

[happysalada]

Thanks a lot!

[happysalada]

@GrahamcOfBorg eval

[happysalada]

@GrahamcOfBorg eval

[happysalada]

I briefly tested this on arm and got some errors. absolutely no worries though.
also, there was an interesting article on linkers, rust and nixos recently.
https://matklad.github.io/2022/03/14/rpath-or-why-lld-doesnt-work-on-nixos.html
you might need to do stuff with the rpath as well, just putting it for your information.

[rgnns]

@happysalada that's interesting. I tried using lld and it doesn't work while zld did (for a Cargo project). This was running from an M1 machine.

[happysalada]

it looks like there are two things.
there is llvm.lld and there is llvm.bintools.lld
the bintools one has an additional wrapper around it (can be found in bintools-wrapper/ld-wrapper.sh
here is the issue tracking it #24744

it's incredibly confusing, but yeah, llvm.bintools.lld seems to be the right one.

[rgnns]

What error did you get when running sod on arm?

[happysalada]

I get exactly rpath problems.
So to be sure I've got
export RUSTFLAGS="-Clink-arg=-fuse-ld=${pkgs.zld}/bin/zld
then I get an error Library no loaded: @rpath/libLTO.dylib
Referenced from nix_zld_path/bin/zld
Reason tried nix_zld_path/bin/libLTO.dylib (no such file)

just replace nix_zld_path with the nix zld path.
So it's either missing something in the output derivation, or it's a matter of setting the rpath correctly.
Perhaps it needs a wrapper just like ld-wrapper