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In-Reply-To: <63c2936e-6bc7-67e3-eaf3-0123333381f8@landley.net>
From:   Masahiro Yamada <masahiroy@kernel.org>
Date:   Thu, 23 Feb 2023 14:31:50 +0900
Message-ID: <CAK7LNASA+Dpe9nv4afnueFeRj4BZDUccOFGJRPr7_rZQ7ZZKaA@mail.gmail.com>
Subject: Re: [PATCH 1/5] try generic compiler name "cc" before falling back to "gcc".
To:     Rob Landley <rob@landley.net>
Cc:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Nicolas Schier <nicolas@fjasle.eu>, Tom Rix <trix@redhat.com>,
        linux-kbuild@vger.kernel.org, llvm@lists.linux.dev
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On Wed, Feb 22, 2023 at 5:41 AM Rob Landley <rob@landley.net> wrote:
>
> Distros like debian install the generic "cc" name for both gcc and clang,
> and the plumbing already does CC_VERSION_TEXT to include Makefile.clang.
>
> Previously: https://lkml.iu.edu/hypermail/linux/kernel/2202.0/01505.html
> Signed-off-by: Rob Landley <rob@landley.net>
> ---
>  Makefile | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index 3f6628780eb2..0ac57ae3b45f 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -456,7 +456,7 @@ endif
>  HOSTCC = $(LLVM_PREFIX)clang$(LLVM_SUFFIX)
>  HOSTCXX        = $(LLVM_PREFIX)clang++$(LLVM_SUFFIX)
>  else
> -HOSTCC = gcc
> +HOSTCC := $(shell cc --version >/dev/null 2>&1 && echo cc || echo gcc)


'cc' only makes sense for the host compiler,
which is configured by 'update-alternative'.

I tried it before, but LLVM folks preferred
using $(LLVM) to choose clang/gcc.


>  HOSTCXX        = g++
>  endif
>  HOSTRUSTC = rustc
> @@ -503,7 +503,8 @@ OBJDUMP             = $(LLVM_PREFIX)llvm-objdump$(LLVM_SUFFIX)
>  READELF                = $(LLVM_PREFIX)llvm-readelf$(LLVM_SUFFIX)
>  STRIP          = $(LLVM_PREFIX)llvm-strip$(LLVM_SUFFIX)
>  else
> -CC             = $(CROSS_COMPILE)gcc
> +CC             := $(CROSS_COMPILE)$(shell $(CROSS_COMPILE)cc --version \
> +                       >/dev/null 2>&1 && echo cc || echo gcc)

This hunk sets up GCC/binutils.
So, cc does not make sense.  NACK.


>  LD             = $(CROSS_COMPILE)ld
>  AR             = $(CROSS_COMPILE)ar
>  NM             = $(CROSS_COMPILE)nm


-- 
Best Regards
Masahiro Yamada