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Date: Mon, 04 Jun 2018 23:49:18 +0200
From: Stefan Agner <stefan@agner.ch>
To: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
        Kees Cook <keescook@chromium.org>, Nicholas Piggin <npiggin@gmail.com>,
        "Luis R . Rodriguez" <mcgrof@suse.com>,
        Randy Dunlap <rdunlap@infradead.org>,
        Ulf Magnusson <ulfalizer@gmail.com>, Sam Ravnborg <sam@ravnborg.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-kbuild-owner@vger.kernel.org
Subject: Re: [PATCH v5 24/31] kconfig: add CC_IS_GCC and GCC_VERSION
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Hi Masahiro,

On 28.05.2018 11:22, Masahiro Yamada wrote:
> This will be useful to specify the required compiler version,
> like this:
> 
> config FOO
>         bool "Use Foo"
>         depends on GCC_VERSION >= 40800
>         help
>           This feature requires GCC 4.8 or newer.
> 

I tried using CC_IS_GCC today while using clang. It seems that it is set
to y despite I am using CC=clang.

.config looks like this after config:

...
CONFIG_CC_IS_GCC=y
CONFIG_GCC_VERSION=40201
CONFIG_CC_IS_CLANG=y
CONFIG_CLANG_VERSION=60000
...


I am using clang 6.0.0 on Arch Linux, which seems to return a version
when using gcc-version.sh:
./scripts/gcc-version.sh clang | sed 's/^0*//'
402

I guess that should not be the case?

--
Stefan

> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> ---
> 
> Changes in v5: None
> Changes in v4: None
> Changes in v3: None
> Changes in v2: None
> 
>  init/Kconfig | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/init/Kconfig b/init/Kconfig
> index f1b0cfb..2e33d93 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -8,6 +8,14 @@ config DEFCONFIG_LIST
>  	default ARCH_DEFCONFIG
>  	default "arch/$(ARCH)/defconfig"
>  
> +config CC_IS_GCC
> +	def_bool $(success,$(CC) --version | grep -q gcc)
> +
> +config GCC_VERSION
> +	int
> +	default $(shell,$(srctree)/scripts/gcc-version.sh -p $(CC) | sed
> 's/^0*//') if CC_IS_GCC
> +	default 0
> +
>  config CONSTRUCTORS
>  	bool
>  	depends on !UML