Re: [PATCH 01/11] Compiler Attributes: Add __require_explicit_initialization macro

From: Kees Cook <kees@kernel.org>
To: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: "Ian Rogers" <irogers@google.com>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	"Danilo Krummrich" <dakr@kernel.org>,
	"Miguel Ojeda" <ojeda@kernel.org>,
	"Nathan Chancellor" <nathan@kernel.org>,
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Subject: Re: [PATCH 01/11] Compiler Attributes: Add __require_explicit_initialization macro
Date: Wed, 14 Oct 2026 09:37:44 -0700	[thread overview]
Message-ID: <202610140937.B68C8C9AAC@keescook> (raw)
In-Reply-To: <CANiq72mLUh1JB=9e=tqStuL_H3=Ormx5v-uFkCDp-0zZm7tBrQ@mail.gmail.com>

On Wed, Oct 14, 2026 at 01:28:55PM +0200, Miguel Ojeda wrote:
> On Wed, Oct 14, 2026 at 12:40 AM Ian Rogers <irogers@google.com> wrote:
> >
> > +/*
> > + * Optional: not supported by gcc
> > + *
> > + * clang: https://clang.llvm.org/docs/AttributeReference.html#require-explicit-initialization
> > + */
> > +#if __has_attribute(__require_explicit_initialization__)
> > +# define __require_explicit_initialization __attribute__((__require_explicit_initialization__))
> > +#else
> > +# define __require_explicit_initialization
> > +#endif
> 
> The LPC slides mention Clang 14+, but from a quick test in Compiler
> Explorer and a `git log --grep` on the LLVM repository to confirm, it
> seems the attribute was introduced in Clang 20+, no?
> 
> If that is correct, then it is not available in all LLVM versions we
> support (LLVM 17+), so we should add:
> 
>      * Optional: only supported since clang >= 20.0
> 
> With that:
> 
> Acked-by: Miguel Ojeda <ojeda@kernel.org>

Yup, I can confirm, I only see it with 20+ too.

-- 
Kees Cook