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From: Nathan Chancellor <nathan@kernel.org>
To: Miguel Ojeda <ojeda@kernel.org>
Cc: "Nicolas Schier" <nsc@kernel.org>,
	"Boqun Feng" <boqun@kernel.org>, "Gary Guo" <gary@garyguo.net>,
	"Matthew Maurer" <mmaurer@google.com>,
	"Alice Ryhl" <aliceryhl@google.com>,
	"Josh Poimboeuf" <jpoimboe@kernel.org>,
	"Peter Zijlstra" <peterz@infradead.org>,
	linux-kbuild@vger.kernel.org,
	"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
	"Benno Lossin" <lossin@kernel.org>,
	"Andreas Hindborg" <a.hindborg@kernel.org>,
	"Trevor Gross" <tmgross@umich.edu>,
	"Danilo Krummrich" <dakr@kernel.org>,
	"Daniel Almeida" <daniel.almeida@collabora.com>,
	"Tamir Duberstein" <tamird@kernel.org>,
	"Alexandre Courbot" <acourbot@nvidia.com>,
	"Onur Özkan" <work@onurozkan.dev>,
	rust-for-linux@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH 2/2] kbuild: rust: keep Rust objects out of Clang LTO with inline helpers
Date: Mon, 17 Aug 2026 11:12:12 -0700	[thread overview]
Message-ID: <20260817181212.GA1249844@ax162> (raw)
In-Reply-To: <20260816133233.197500-2-ojeda@kernel.org>

On Sun, Aug 16, 2026 at 03:32:33PM +0200, Miguel Ojeda wrote:
> Another possible alternative that Gary suggested is to turn the flags on
> globally for C, whether only when inline helpers are enabled or in all
> cases, but it may be intended that in C we expect not to generate the
> `unreachable`s.

I am not sure we can use '-mllvm -trap-unreachable' for C code, as that
would mess with manually inserted calls to __builtin_unreachable(). It
has come up before:

  https://lore.kernel.org/CAHk-=wgPCbZv0JgqoNWMOO+p=N772YW16xYk_pmb1GU7aeuPFA@mail.gmail.com/

It is possible the '-no-trap-after-noreturn' avoids that particular
issue but I still think the "compiler inserted" vs. "user inserted"
distinction that Linus comments on is likely still potentially relevant.

-- 
Cheers,
Nathan

  parent reply	other threads:[~2026-08-17 18:12 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-16 13:32 [PATCH 1/2] kbuild: rust: preserve unreachable traps with inline helpers Miguel Ojeda
2026-08-16 13:32 ` [PATCH 2/2] kbuild: rust: keep Rust objects out of Clang LTO " Miguel Ojeda
2026-08-16 14:05   ` Gary Guo
2026-08-17 18:12   ` Nathan Chancellor [this message]
2026-08-16 14:04 ` [PATCH 1/2] kbuild: rust: preserve unreachable traps " Gary Guo
2026-08-18  3:18 ` Josh Poimboeuf

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