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Date: Wed, 31 Aug 2022 13:23:00 -0700
From: Nathan Chancellor <nathan@kernel.org>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>,
	Michal Marek <michal.lkml@markovi.net>, Tom Rix <trix@redhat.com>,
	linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
	llvm@lists.linux.dev, x86@kernel.org,
	Dmitrii Bundin <dmitrii.bundin.a@gmail.com>,
	Fangrui Song <maskray@google.com>,
	Alexey Alexandrov <aalexand@google.com>,
	Bill Wendling <morbo@google.com>, Greg Thelen <gthelen@google.com>,
	Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH v2 5/5] Makefile.debug: set -g unconditional on
 CONFIG_DEBUG_INFO_SPLIT
Message-ID: <Yw/DJLu10nw4aUDw@dev-arch.thelio-3990X>
References: <20220831184408.2778264-1-ndesaulniers@google.com>
 <20220831184408.2778264-6-ndesaulniers@google.com>
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In-Reply-To: <20220831184408.2778264-6-ndesaulniers@google.com>

On Wed, Aug 31, 2022 at 11:44:08AM -0700, Nick Desaulniers wrote:
> Dmitrii, Fangrui, and Mashahiro note:
> 
>   Before GCC 11 and Clang 12 -gsplit-dwarf implicitly uses -g2.
> 
> Fix CONFIG_DEBUG_INFO_SPLIT for gcc-11+ & clang-12+ which now need -g
> specified in order for -gsplit-dwarf to work at all.
> 
> -gsplit-dwarf has been mutually exclusive with -g since support for
> CONFIG_DEBUG_INFO_SPLIT was introduced in
> commit 866ced950bcd ("kbuild: Support split debug info v4")
> I don't think it ever needed to be.
> 
> Link: https://lore.kernel.org/lkml/20220815013317.26121-1-dmitrii.bundin.a@gmail.com/
> Link: https://lore.kernel.org/lkml/CAK7LNARPAmsJD5XKAw7m_X2g7Fi-CAAsWDQiP7+ANBjkg7R7ng@mail.gmail.com/
> Link: https://reviews.llvm.org/D80391
> Cc: Andi Kleen <ak@linux.intel.com>
> Reported-by: Dmitrii Bundin <dmitrii.bundin.a@gmail.com>
> Reported-by: Fangrui Song <maskray@google.com>
> Reported-by: Masahiro Yamada <masahiroy@kernel.org>
> Suggested-by: Dmitrii Bundin <dmitrii.bundin.a@gmail.com>
> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>

Reviewed-by: Nathan Chancellor <nathan@kernel.org>

> ---
> Changes v1 -> v2:
> * Add reference to 866ced950bcd, cc Andi, in commit message.
> 
>  scripts/Makefile.debug | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/scripts/Makefile.debug b/scripts/Makefile.debug
> index 46e88f0ca998..b6eb532af3cc 100644
> --- a/scripts/Makefile.debug
> +++ b/scripts/Makefile.debug
> @@ -1,10 +1,8 @@
> -DEBUG_CFLAGS	:=
> +DEBUG_CFLAGS	:= -g
> +KBUILD_AFLAGS	+= -g
>  
>  ifdef CONFIG_DEBUG_INFO_SPLIT
>  DEBUG_CFLAGS	+= -gsplit-dwarf
> -else
> -DEBUG_CFLAGS	+= -g
> -KBUILD_AFLAGS	+= -g
>  endif
>  
>  ifdef CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
> -- 
> 2.37.2.672.g94769d06f0-goog
>