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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Tue, 5 Dec 2023 13:57:38 -0800
Message-ID: <CAKwvOdki0aUFLOgEhDxtHdHk_6x7WZdt3k2rSCxTB5hkPfKYWw@mail.gmail.com>
Subject: Re: [PATCH] lib/string: shrink lib/string.i via IWYU
To:     Al Viro <viro@zeniv.linux.org.uk>
Cc:     Andrew Morton <akpm@linux-foundation.org>, tanzirh@google.com,
        Kees Cook <keescook@chromium.org>,
        Andy Shevchenko <andy@kernel.org>,
        linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org,
        Nick DeSaulniers <nnn@google.com>, llvm@lists.linux.dev
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On Tue, Dec 5, 2023 at 1:44=E2=80=AFPM Al Viro <viro@zeniv.linux.org.uk> wr=
ote:
>
> On Tue, Dec 05, 2023 at 01:39:47PM -0800, Nick Desaulniers wrote:
>
> > The tooling Tanzir is working on does wrap IWYU, and does support such
> > mapping (of 'low level' to 'high level' headers; more so, if it
> > recommends X you can override to suggest Y instead).
> >
> > arch/nios/ also doesn't provide a bug.h, which this patch is
> > suggesting we include directly.  I guess the same goes for
> > asm/rwonce.h.
>
> See include/asm-generic/Kbuild:
> mandatory-y +=3D bug.h
> ...
> mandatory-y +=3D rwonce.h
>
> IOW, sh will have asm/bug.h and as/rwonce.h copied from asm-generic.

Ah, right, Ard had mentioned this file to me once.  And mandatory-y is
documented in Documentation/kbuild/makefiles.rst.

Ok, so we can use include/asm-generic/Kbuild to know that if the .h
files listed there are recommended to include as asm/*.h, then we
should replace that recommendation with linux/*.h.  Our tooling has
something where we can automate that.

>
> Still, includes of asm/*.h had been a massive headache historically
> and breeding more of those shouldn't be overdone.
>
> More painful problem is arch- and config-dependent stuff, though...
--=20
Thanks,
~Nick Desaulniers