On Sat, 2024-11-09 at 17:45 +0100, Michał Górny wrote: > Hi, > > Long story short, a lot of Rust upstreams are ricing in their > Cargo.toml: enabling LTO, adjusting LTO jobs to exactly 1, and even > weirder stuff. With C, we generally have clear policies to override > this and respect user flags. With Rust, things aren't that clear. > > Say, let's look at fractal: > > [profile.release] > debug = true > lto = "thin" > codegen-units = 1 > > Upstream is enabling LTO with 1 job (i.e. single threaded) to squeeze > as much as they can from it. Also, they are enabling debug symbols for > some reason. As a result, the build takes 45 minutes, if it doesn't OOM > first. > > How much of that stuff should we respect? Or should we perhaps override > it all? Should we do some special magic via eclass, or perhaps expect > users to set specific RUSTFLAGS for that? Perhaps set default RUSTFLAGS > in the profiles?
This stuff is unbelievably messy. Read the comments in cargo.eclass regarding RUSTFLAGS. As things stand, user RUSTFLAGS are respected, as are some project-specific flags but not all. When I worked on this, I didn't look into these profile-related settings. Do these actually have anything to do with RUSTFLAGS? I'm not sure. gyakovlev experimented with a "gentoo" (as opposed to "release") profile a while back, but that effort stalled.
signature.asc
Description: This is a digitally signed message part
