On Wed, Aug 26, 2020 at 01:14:19PM -0700, Nick Desaulniers wrote:
> During Plumbers 2020, we voted to just support the latest release of
> Clang for now. Add a compile time check for this.
>
> Older clang's may work, but we will likely drop workarounds for older
> versions.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/9
> Link: https://github.com/ClangBuiltLinux/linux/issues/941
> Suggested-by: Sedat Dilek <sedat.di...@gmail.com>
> Signed-off-by: Nick Desaulniers <ndesaulni...@google.com>
> ---
> include/linux/compiler-clang.h | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
> index cee0c728d39a..7338d3ffd240 100644
> --- a/include/linux/compiler-clang.h
> +++ b/include/linux/compiler-clang.h
> @@ -3,6 +3,14 @@
> #error "Please don't include <linux/compiler-clang.h> directly, include
> <linux/compiler.h> instead."
> #endif
>
> +#define CLANG_VERSION (__clang_major__ * 10000 \
> + + __clang_minor__ * 100 \
> + + __clang_patchlevel__)
> +
> +#if CLANG_VERSION < 100001
> +# error Sorry, your compiler is too old - please upgrade it.
Perhaps a bike-shed suggestion, but I think we should make this message
as specific (and helpful) as possible:
# error Sorry, your version of Clang is too old - please use 10.0.1 or newer.
Then anyone seeing this has several pieces of information:
- the kernel build was attempting to use Clang
(maybe they accidentally poked the wrong configs in a CI)
- they need 10.0.1 or better
("upgrade to what version?" doesn't need to be dug out of documentation,
headers, etc)
With that, yes, let's do it. :)
Reviewed-by: Kees Cook <keesc...@chromium.org>
(And likely we should improve the GCC message at the same time...)
--
Kees Cook
