bug#57303: powerpc64le: rust build failure is bottleneck for many packages

[Maxim Cournoyer]

tags 57303 +notabug
thanks

Hi!

Marcel van der Boom <marcel@van-der-boom.nl> writes:

> I use a Talos II machine as my daily driver and slowly migrating 
> as many packages to GUIX along the way. The kernel I am running 
> comes fromm https://archlinuxpower.org/

Cool!

> For many packages, rust is getting to be the bottleneck as a 
> dependency that does not build.
>
>>From what I can see there's a whole chain of rust dependencies 
> going back to rust@1.39.0 which then ultimately fails with:
>
> (16/112) BUILDING bitflags v1.1.0
>> /tmp/guix-build-rust-1.39.0.drv-0/mrustc/bin/mrustc 
>> rustc-1.39.0-src/vendor/bitflags/src/lib.rs -o 
>> output/rustc-build/libbitflags-1_1_0.rlib --crate-name bitflags 
>> --crate-type rlib -C 
>> emit-depfile=output/rustc-build/libbitflags-1_1_0.rlib.d 
>> --crate-tag 1_1_0 -g --cfg debug_assertions -O -L output -L 
>> output/rustc-build --cfg bitflags_const_fn
> (17/112) BUILDING cc v1.0.35
>> /tmp/guix-build-rust-1.39.0.drv-0/mrustc/bin/mrustc 
>> rustc-1.39.0-src/vendor/cc/src/lib.rs -o 
>> output/rustc-build/libcc-1_0_35.rlib --crate-name cc 
>> --crate-type rlib -C 
>> emit-depfile=output/rustc-build/libcc-1_0_35.rlib.d --crate-tag 
>> 1_0_35 -g --cfg debug_assertions -O -L output -L 
>> output/rustc-build
>> /tmp/guix-build-rust-1.39.0.drv-0/mrustc/bin/mrustc 
>> rustc-1.39.0-src/src/librustc_llvm/build.rs --crate-name build 
>> --crate-type bin -o output/rustc-build/build_rustc_llvm_run -L 
>> output/rustc-build -g -L output --extern 
>> build_helper=output/rustc-build/libbuild_helper-0_1_0.rlib 
>> --extern cc=output/rustc-build/libcc-1_0_35.rlib --edition 2018
>> /tmp/guix-build-rust-1.39.0.drv-0/mrustc/output/rustc-build/build_rustc_llvm_run
> thread 'main' panicked at 'assertion failed: `(left == right)`
>   left: `1`,
>  right: `0`', 
>  rustc-1.39.0-src/vendor/hashbrown/src/raw/mod.rs:1086:59
> Process was terminated with signal 6
>
>
> The line in =mod.rs= points to an assertion in some sort of table 
> iterator. Way over my head.

Working only on x86_64 is a limitation of mrustc, which is used to
bootstrap rust cleanly from sources on Guix.

> I know rust runs on powerpc64le because I have a binary version 
> 1.62 installed through https://archlinuxpower.org/

Yes, Rust itself is not the problem, but its bootstrap.

I'd suggest lending a hand to mrustc to iron out issues like this or
request to Rust upstream support for bootstrapping for sources.
Investigating future alternatives such as GCC Rust or other similar
efforts could be useful for the time they are ripe to use, too.

Closing, as there's not much we can do on Guix's side.

Thanks,

Maxim