Re: [PATCH v2 2/3] scripts: generate_rust_target: enable building on RISC-V

From: Conor Dooley <conor@kernel.org>
To: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: "Conor Dooley" <conor.dooley@microchip.com>,
	linux-riscv@lists.infradead.org,
	"Miguel Ojeda" <ojeda@kernel.org>,
	"Alex Gaynor" <alex.gaynor@gmail.com>,
	"Wedson Almeida Filho" <wedsonaf@gmail.com>,
	"Boqun Feng" <boqun.feng@gmail.com>,
	"Gary Guo" <gary@garyguo.net>,
	"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"Paul Walmsley" <paul.walmsley@sifive.com>,
	"Palmer Dabbelt" <palmer@dabbelt.com>,
	"Nathan Chancellor" <nathan@kernel.org>,
	"Nick Desaulniers" <ndesaulniers@google.com>,
	"Tom Rix" <trix@redhat.com>,
	rust-for-linux@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org, llvm@lists.linux.dev
Subject: Re: [PATCH v2 2/3] scripts: generate_rust_target: enable building on RISC-V
Date: Tue, 27 Feb 2024 18:24:06 +0000	[thread overview]
Message-ID: <20240227-aside-limeade-497fb182a5bd@spud> (raw)
In-Reply-To: <CANiq72kQ8===wFLQNCR-XAo9KdtPr44UKvyi2074J88vh3kvyg@mail.gmail.com>

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On Tue, Feb 27, 2024 at 07:11:17PM +0100, Miguel Ojeda wrote:
> On Tue, Feb 27, 2024 at 6:48 PM Conor Dooley <conor@kernel.org> wrote:

> For instance, to disable the compressed instructions, from what I can
> tell, the flag I mentioned seems to work, so that is fine.

To me, using flags is a good fit given that's what we do elsewhere,
and there won't be a mix of stuff that is done conditionally in a
script and conditionally in a Makefile.

> However,
> for something like tweaking the data layout for `n64` instead of
> `n32:64`, I am not aware of a way to do so via a flag (but I see newer
> LLVM uses `n32:64`, so that may be the better one anyway:
> https://godbolt.org/z/Eh4cfdeMr).

Yeah, I had looked at the blame for the targets earlier today and
noticed that it had been changed. Sadly rustc's commit is lacking
any justification whatsoever for the change, so I was not going to
really comment on that until I had looked.

> So it all depends on whether you are happy with what the flags
> approach already give you.
> 
> I hope that clarifies a bit!

Ye, thanks. I'll give it a go when I have a bit of time this week.

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