rav1d fails to build on aarch64

[negge]

I tried to build rav1d on aarch64 and get the following error:

# cargo build --release
error: cannot produce proc-macro for `atomig-macro v0.3.0` as the target `aarch64-unknown-linux-gnu` does not support these crate types

This is using the latest rust on Ubuntu rustc 1.76.0-nightly (6b771f6b5 2023-11-15)

[kkysen]

What OS are you encountering this on? I don't think it's an issue with aarch64-unnknown-linux-gnu in general, since @fbossen has been compiling and running rav1d on aarch64-unnknown-linux-gnu on macOS. Perhaps it is an issue with +crt-static and static linking (rust-lang/rust#78210)?

[fbossen]

I am running into the same issue as @negge on a Raspberry Pi with Ubuntu 22.04. As @kkysen points out, no such issue on macOS for aarch64.

[fbossen]

@negge I seem to have better luck with cargo build --release --target aarch64-unknown-linux-gnu

[rinon]

This might be an issue with atomig itself: https://docs.rs/atomig/latest/atomig/#notes ("This has the unfortunate effect that this whole library will fail to compile on any targets where any of the atomic methods/types are unavailable."). We don't really need this dependency, so we should probably just replace it.

[fbossen]

This might be an issue with atomig itself: https://docs.rs/atomig/latest/atomig/#notes ("This has the unfortunate effect that this whole library will fail to compile on any targets where any of the atomic methods/types are unavailable."). We don't really need this dependency, so we should probably just replace it.

Not sure the issue is with atomig itself. The same issue was present earlier with paste

[negge]

@negge I seem to have better luck with cargo build --release --target aarch64-unknown-linux-gnu

Thanks @fbossen, I was able to build the project with that command line.

[kkysen]

@negge, we figured out that our .cargo/config.toml with rustflags set to -C target-feature=+crt-static was the issue. We had added that to cross-compile and run with qemu, and we're trying to figure out how to support both qemu and normal builds. In the meantime, manually specifying --target aarch64-unknown-linux-gnu should work as @fbossen pointed out.

[LukasKalbertodt]

The error message in the top comment suggests that this has nothing to do with any atomic operations, but with the fact that proc-macro crates are not supported in certain build/target configurations. There seems to be a solution to this issue now, but to throw out another way to fix this: you can remove the derive feature from atomig and replace these derives of Atom and AtomLogic with manual impls:

impl atomic::Atom for PictureFlags {
    type Repr = u8;
    fn pack(self) -> Self::Repr { self. 0 }
    fn unpack(src: Self::Repr) -> Self { Self(src) }
}
impl atomic::AtomLogic for PictureFlags {}