linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Kees Cook <keescook@chromium.org>
To: "Valdis Klētnieks" <valdis.kletnieks@vt.edu>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	linux-hardening@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RESEND] gcc-plugins: avoid errors with -std=gnu++11 on old gcc
Date: Wed, 17 Mar 2021 22:52:56 -0700	[thread overview]
Message-ID: <202103172251.F9D770D@keescook> (raw)
In-Reply-To: <279558.1615192821@turing-police>

On Mon, Mar 08, 2021 at 03:40:21AM -0500, Valdis Klētnieks wrote:
> It turns out that older gcc (4.9 and 5.4) have gnu++11 support, but
> due to a gcc bug fixed in gcc6, throw errors during the build.
> The relevant gcc bug is https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69959
> 
> Version the option based on what gcc we're using.

Is there a better way to detect this than with version checking?

-Kees

> 
> Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
> Fixes: 27c287b41659 ("gcc-plugins: fix gcc 11 indigestion with plugins...")
> ---
> diff --git a/scripts/gcc-plugins/Makefile b/scripts/gcc-plugins/Makefile
> index b5487cce69e8..cc779973724a 100644
> --- a/scripts/gcc-plugins/Makefile
> +++ b/scripts/gcc-plugins/Makefile
> @@ -21,8 +21,11 @@ always-y += $(GCC_PLUGIN)
>  
>  GCC_PLUGINS_DIR = $(shell $(CC) -print-file-name=plugin)
>  
> +# need gnu++11 for gcc 11, but 4.9 and 5.4 need gnu++98
> +GCC_FLAVOR = $(call cc-ifversion, -ge, 1100, 11, 98)
> +
>  plugin_cxxflags	= -Wp,-MMD,$(depfile) $(KBUILD_HOSTCXXFLAGS) -fPIC \
> -		   -I $(GCC_PLUGINS_DIR)/include -I $(obj) -std=gnu++11 \
> +		   -I $(GCC_PLUGINS_DIR)/include -I $(obj) -std=gnu++$(GCC_FLAVOR) \
>  		   -fno-rtti -fno-exceptions -fasynchronous-unwind-tables \
>  		   -ggdb -Wno-narrowing -Wno-unused-variable \
>  		   -Wno-format-diag
> 
> 

-- 
Kees Cook

  reply	other threads:[~2021-03-18  5:54 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-08  8:40 [PATCH RESEND] gcc-plugins: avoid errors with -std=gnu++11 on old gcc Valdis Klētnieks
2021-03-18  5:52 ` Kees Cook [this message]
2021-03-18  6:02   ` Valdis Klētnieks
2021-03-18  6:26     ` Miguel Ojeda
2021-03-18  9:07       ` Masahiro Yamada
2021-03-18 11:47         ` Valdis Klētnieks
2021-03-18 11:41     ` David Laight
2021-03-18 11:55       ` Valdis Klētnieks
2021-03-18 13:38         ` David Laight

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=202103172251.F9D770D@keescook \
    --to=keescook@chromium.org \
    --cc=geert@linux-m68k.org \
    --cc=jpoimboe@redhat.com \
    --cc=linux-hardening@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=valdis.kletnieks@vt.edu \
    /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
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
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).