LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Masahiro Yamada <yamada.masahiro@socionext.com>
To: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Nathan Chancellor <natechancellor@gmail.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Clang-Built-Linux ML <clang-built-linux@googlegroups.com>,
	Michal Marek <michal.lkml@markovi.net>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] kbuild: add most of Clang-specific flags unconditionally
Date: Fri, 10 May 2019 22:53:14 +0900	[thread overview]
Message-ID: <CAK7LNAS+FQqQZ0RfW8e6mxabUOq9YVk=eEEztmN-+BHnTmDa_w@mail.gmail.com> (raw)
In-Reply-To: <CA+icZUX_AgZdH5Z+1+k+oVdYSo7vqzeJsGPndb_Sa8VOSk_yOg@mail.gmail.com>

On Thu, May 9, 2019 at 4:06 PM Sedat Dilek <sedat.dilek@gmail.com> wrote:
>
> On Thu, May 9, 2019 at 8:45 AM Masahiro Yamada
> <yamada.masahiro@socionext.com> wrote:
> >
> > We do not support old Clang versions. Upgrade your clang version
> > if any of these flags is unsupported.
> >
> > Let's add flags within ifdef CONFIG_CC_IS_CLANG unconditionally,
> > except -fcatch-undefined-behavior.
> >
> > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
>
> Looks good to me.
>
> Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com>
>
> Just as sidenote:
> I experimented with a snapshot version of clang-9 and lld-9 and could
> build, link and boot on bare-metal with '-mglobal-merge' on
> Debian/buster AMD64.


The comment says
 # CLANG uses a _MergedGlobals as optimization, but this breaks modpost, as the
 # source of a reference will be _MergedGlobals and not on of the
whitelisted names.
 # See modpost pattern 2

So, it seems it is just a matter of modpost,
but I am not sure enough.

This flag has been here since the initial support.
(61163efae02040f66a95c8ed17f4407951ba58fa)


Perhaps, we should review clang flags one by one again?




> But forgot to document in [1].
>
> [1] https://github.com/ClangBuiltLinux/linux/issues/431



-- 
Best Regards
Masahiro Yamada

  reply	other threads:[~2019-05-10 13:54 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-09  6:44 Masahiro Yamada
2019-05-09  7:06 ` Sedat Dilek
2019-05-10 13:53   ` Masahiro Yamada [this message]
2019-05-10 17:57     ` Nick Desaulniers
2019-05-09 11:15 ` Nathan Chancellor
2019-05-09 11:35   ` Masahiro Yamada
2019-05-09 11:40     ` Nathan Chancellor
2019-05-09 11:48     ` [PATCH] Makefile: Don't try to add '-fcatch-undefined-behavior' flag Nathan Chancellor
2019-05-09 13:33       ` Masahiro Yamada
2019-05-09 13:49       ` Sedat Dilek
2019-05-09 17:01         ` Nick Desaulniers
2019-05-13  2:23       ` Masahiro Yamada
2019-05-09 17:17   ` [PATCH] kbuild: add most of Clang-specific flags unconditionally Nick Desaulniers

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAK7LNAS+FQqQZ0RfW8e6mxabUOq9YVk=eEEztmN-+BHnTmDa_w@mail.gmail.com' \
    --to=yamada.masahiro@socionext.com \
    --cc=arnd@arndb.de \
    --cc=clang-built-linux@googlegroups.com \
    --cc=linux-kbuild@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=michal.lkml@markovi.net \
    --cc=natechancellor@gmail.com \
    --cc=ndesaulniers@google.com \
    --cc=sedat.dilek@gmail.com \
    --subject='Re: [PATCH] kbuild: add most of Clang-specific flags unconditionally' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).