Re: [PATCH AUTOSEL 5.10 45/51] gcc-plugins: fix gcc 11 indigestion with plugins...

[Kees Cook]

This will need an additional fix, so please don't backport it yet.

On Tue, Jan 12, 2021 at 07:55:27AM -0500, Sasha Levin wrote:
> From: Valdis Klētnieks <valdis.kletnieks@xxxxxx>
> 
> [ Upstream commit 67a5a68013056cbcf0a647e36cb6f4622fb6a470 ]
> 
> Fedora Rawhide has started including gcc 11,and the g++ compiler
> throws a wobbly when it hits scripts/gcc-plugins:
> 
>   HOSTCXX scripts/gcc-plugins/latent_entropy_plugin.so
> In file included from /usr/include/c++/11/type_traits:35,
>                  from /usr/lib/gcc/x86_64-redhat-linux/11/plugin/include/system.h:244,
>                  from /usr/lib/gcc/x86_64-redhat-linux/11/plugin/include/gcc-plugin.h:28,
>                  from scripts/gcc-plugins/gcc-common.h:7,
>                  from scripts/gcc-plugins/latent_entropy_plugin.c:78:
> /usr/include/c++/11/bits/c++0x_warning.h:32:2: error: #error This file requires compiler and library support for the ISO
>  C++ 2011 standard. This support must be enabled with the -std=c++11 or -std=gnu++11 compiler options.
>    32 | #error This file requires compiler and library support \
> 
> In fact, it works just fine with c++11, which has been in gcc since 4.8,
> and we now require 4.9 as a minimum.
> 
> Signed-off-by: Valdis Kletnieks <valdis.kletnieks@xxxxxx>
> Acked-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> Link: https://lore.kernel.org/r/82487.1609006918@turing-police
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> ---
>  scripts/gcc-plugins/Makefile | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/scripts/gcc-plugins/Makefile b/scripts/gcc-plugins/Makefile
> index d66949bfeba45..b5487cce69e8e 100644
> --- a/scripts/gcc-plugins/Makefile
> +++ b/scripts/gcc-plugins/Makefile
> @@ -22,9 +22,9 @@ always-y += $(GCC_PLUGIN)
>  GCC_PLUGINS_DIR = $(shell $(CC) -print-file-name=plugin)
>  
>  plugin_cxxflags	= -Wp,-MMD,$(depfile) $(KBUILD_HOSTCXXFLAGS) -fPIC \
> -		   -I $(GCC_PLUGINS_DIR)/include -I $(obj) -std=gnu++98 \
> +		   -I $(GCC_PLUGINS_DIR)/include -I $(obj) -std=gnu++11 \
>  		   -fno-rtti -fno-exceptions -fasynchronous-unwind-tables \
> -		   -ggdb -Wno-narrowing -Wno-unused-variable -Wno-c++11-compat \
> +		   -ggdb -Wno-narrowing -Wno-unused-variable \
>  		   -Wno-format-diag
>  
>  plugin_ldflags	= -shared
> -- 
> 2.27.0
> 

-- 
Kees Cook