[PATCH v3 5/5] Makefile.debug: set -g unconditional on CONFIG_DEBUG_INFO_SPLIT

From: Nick Desaulniers <ndesaulniers@google.com>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: Michal Marek <michal.lkml@markovi.net>,
	Nathan Chancellor <nathan@kernel.org>,  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>,
	 Nick Desaulniers <ndesaulniers@google.com>,
	Andi Kleen <ak@linux.intel.com>
Subject: [PATCH v3 5/5] Makefile.debug: set -g unconditional on CONFIG_DEBUG_INFO_SPLIT
Date: Tue,  6 Sep 2022 21:59:07 -0700	[thread overview]
Message-ID: <20220907045907.484043-6-ndesaulniers@google.com> (raw)
In-Reply-To: <20220907045907.484043-1-ndesaulniers@google.com>

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>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
Changes v2 -> v3:
* Pick up Nathan's RB tag.

Changes v1 -> v2:
* Add reference to 866ced950bcd, cc Andi, in commit message.

 scripts/Makefile.debug | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/scripts/Makefile.debug b/scripts/Makefile.debug
index 2845145c1220..c20f8f2e76bf 100644
--- a/scripts/Makefile.debug
+++ b/scripts/Makefile.debug
@@ -1,10 +1,4 @@
-DEBUG_CFLAGS	:=
-
-ifdef CONFIG_DEBUG_INFO_SPLIT
-DEBUG_CFLAGS	+= -gsplit-dwarf
-else
-debug-cflags-y	+= -g
-endif
+DEBUG_CFLAGS	:= -g
 
 debug-flags-$(CONFIG_DEBUG_INFO_DWARF4)	+= -gdwarf-4
 debug-flags-$(CONFIG_DEBUG_INFO_DWARF5)	+= -gdwarf-5
@@ -15,6 +9,8 @@ ifeq ($(CONFIG_CC_IS_CLANG)$(CONFIG_AS_IS_GNU),yy)
 KBUILD_AFLAGS	+= $(addprefix -Wa$(comma), $(debug-flags-y))
 endif
 
+debug-flags-$(CONFIG_DEBUG_INFO_SPLIT)	+= -gsplit-dwarf
+
 ifdef CONFIG_DEBUG_INFO_REDUCED
 DEBUG_CFLAGS	+= -fno-var-tracking
 ifdef CONFIG_CC_IS_GCC
-- 
2.37.2.789.g6183377224-goog

