From: Masahiro Yamada <masahiroy@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Emese Revfy <re.emese@gmail.com>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Kees Cook <keescook@chromium.org>
Subject: Re: [GIT PULL 2/2] Kconfig updates for v5.10-rc1
Date: Wed, 2 Dec 2020 22:03:47 +0900 [thread overview]
Message-ID: <CAK7LNAS_18S9_OasKOaoEW6os3=bYf4wi7fPewfdHyCS2mLsyA@mail.gmail.com> (raw)
In-Reply-To: <CAK7LNAQGHjLYteCt+8BXSY-5CB0gaO1JtHY-SpPFrfdchoHKrQ@mail.gmail.com>
On Wed, Dec 2, 2020 at 9:53 PM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> Hi Linus,
>
> On Sun, Nov 29, 2020 at 3:28 AM Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
> >
> > On Fri, Nov 27, 2020 at 11:05 PM Masahiro Yamada <masahiroy@kernel.org> wrote:
> > >
> > > As for the cc1plus cost, I got a similar result.
> > >
> > > Running scripts/gcc-plugin.sh directly
> > > took me 0.5 sec, which is a fourth
> > > of the allmodconfig run-time.
> > >
> > > Actually, I did not know this shell script
> > > was so expensive to run...
> >
> > So it turns out that one reason it's so expensive to run is that it
> > does a *lot* more than it claims to do.
> >
> > It says "we need a c++ compiler that supports the designated
> > initializer GNU extension", but then it actually includes a header
> > file from hell, rather than just test designated initializers.
> >
> > This patch makes the cc1plus overhead go down a lot. That said, I'm
> > doubtful we really want gcc plugins at all, considering that the only
> > real users have all apparently migrated to clang builtin functionality
> > instead.
> >
> > Linus
>
>
> The attached patch looks OK to me.
>
> Just a nit:
> Now that the test code does not include any header,
> you can also delete
> "-I $srctree/gcc-plugins -I $gccplugins_dir/include"
>
>
> If you apply it directly, please feel free to add
>
> Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
BTW, gcc plugins are always compiled with g++.
Why do we need to compile the following in the first place?
class test {
public:
int test;
} test = {
.test = 1
};
I think any C++ compiler will succeed
in compiling such simple code.
So,
test -e "$gccplugins_dir/include/plugin-version.h"
looks enough to me.
What is the intention of this compile test?
--
Best Regards
Masahiro Yamada
next prev parent reply other threads:[~2020-12-02 13:05 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-22 13:49 [GIT PULL 2/2] Kconfig updates for v5.10-rc1 Masahiro Yamada
2020-10-22 20:25 ` pr-tracker-bot
2020-11-27 21:08 ` Linus Torvalds
2020-11-27 21:15 ` Linus Torvalds
2020-11-27 21:53 ` Linus Torvalds
2020-11-27 22:05 ` Linus Torvalds
2020-11-28 7:04 ` Masahiro Yamada
2020-11-28 18:28 ` Linus Torvalds
2020-12-02 0:55 ` Kees Cook
2020-12-02 12:53 ` Masahiro Yamada
2020-12-02 13:03 ` Masahiro Yamada [this message]
2020-12-02 18:58 ` Kees Cook
2020-12-02 20:13 ` Linus Torvalds
-- strict thread matches above, loose matches on Subject: below --
2020-10-22 13:47 Masahiro Yamada
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