Unable to build with LTO enabled

[txtsd]

When compiling with LTO enabled, the build process fails.

See log:
https://bpa.st/V4KQ

(Couldn't paste the log directly because it's longer than GitHub's maximum character limit)

[k1gen]

+1

[tarkah]

I cannot reproduce on Linux with cargo build --release --config profile.release.lto=\"on\"

[k1gen]

cargo build --release --config profile.release.lto=\"on\" also works for me, but this doesn't: https://aur.archlinux.org/cgit/aur.git/tree/PKGBUILD?h=halloy

[txtsd]

@tarkah The AUR packages do not build with the lto option which is enabled for makepkg by default.
It has to be explicitly disabled for halloy to build.
I tried using your --config suggestion in tandem with the lto build option but that doesn't work either.

[tarkah]

Seems like an issue in the AUR packaging environment then. What linker is being used? Are other rust flags enabled behind the scenes? Which rust version?

[k1gen]

Seems like an issue in the AUR packaging environment then. What linker is being used? Are other rust flags enabled behind the scenes? Which rust version?

$ cat .cargo/config.toml
[profile.release]
strip = true
lto = "thin"

[build]
rustc-wrapper = "sccache"
$ rustc --version
rustc 1.77.2 (25ef9e3d8 2024-04-09)

I have no idea what linker is being used, the only one I have installed is the GNU ld

[txtsd]

There's a known bug that LTO does weird things if you

1. include some C in your rust code
2. compile with GCC (not clang)
3. use lto.

Not doing just one of those three appears to "fix" it

See these:
https://github.com/gyscos/zstd-rs/issues?q=is%3Aissue+undefined+reference+to