[bug#49569] [PATCH] gnu: Add make-single-arch-llvm procedure.

[Thiago Jung Bauermann via Guix-patches via <guix-patches@gnu.org>]

Hello,

Em quinta-feira, 15 de julho de 2021, às 07:04:52 -03, Efraim Flashner
escreveu:
> * gnu/packages/llvm.scm (make-single-arch-llvm): New procedure.
> (llvm-native-12, llvm-native): New variables.
> ---
> 
> Using this copy of llvm for packages like mesa will reduce the closure
> of those packages. I don't suppose it would work as well for compilers
> like rust which use LLVM for compiling and targeting different
> architectures.
> 
> This drops the size of llvm-12 from 167M to 111M.

I don’t have an opinion on the issue that Ludo’ raised, just one comment
about the code below.

>  gnu/packages/llvm.scm | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/gnu/packages/llvm.scm b/gnu/packages/llvm.scm
> index 575c63c713..35cecdfd84 100644
> --- a/gnu/packages/llvm.scm
> +++ b/gnu/packages/llvm.scm
> @@ -1347,3 +1347,27 @@ LLVM."))))
>  (define-public ocaml-llvm-9 (make-ocaml-llvm llvm-9))
>  (define-public ocaml-llvm-10 (make-ocaml-llvm llvm-10))
>  (define-public ocaml-llvm-11 (make-ocaml-llvm llvm-11))
> +
> +(define* (make-single-arch-llvm llvm #:optional (system (or (%current-target-system)
> +                                                            (%current-system))))
> +  (package
> +    (inherit llvm)
> +    (name (string-append "llvm-for-" (string-downcase
> +                                       (system->llvm-target system))))

‘system->llvm-target’ needs a Nix system identifier but
‘%current-target-system’ contains a GNU triplet, so the above won’t work
when cross-compiling for armhf-linux – whose GNU triplet is
“arm-unknown-linux-gnueabihf”.

I suggest changing the default value of ‘system’ to

    (or (and=> (%current-target-system) gnu-triplet->nix-system)
        (%current-system))

which is the default argument for ‘system->llvm-target’.

If I can add a shameless plug, patch 2 of my “Target check fixes and
cleanups” series¹ adds a helper procedure with the code above. :-)

> +    (arguments
> +     (substitute-keyword-arguments (package-arguments llvm)
> +       ((#:configure-flags cf)
> +        `(cons* ,(string-append "-DLLVM_TARGETS_TO_BUILD="
> +                                (system->llvm-target system))

Same problem here.

-- 
Thanks,
Thiago

¹ https://issues.guix.gnu.org/49672