[PATCH v4] Makefile.debug: set -g unconditional on CONFIG_DEBUG_INFO_SPLIT

[Nick Desaulniers]

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@xxxxxxxxx/
Link: https://lore.kernel.org/lkml/CAK7LNARPAmsJD5XKAw7m_X2g7Fi-CAAsWDQiP7+ANBjkg7R7ng@xxxxxxxxxxxxxx/
Link: https://reviews.llvm.org/D80391
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Reported-by: Dmitrii Bundin <dmitrii.bundin.a@xxxxxxxxx>
Reported-by: Fangrui Song <maskray@xxxxxxxxxx>
Reported-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Suggested-by: Dmitrii Bundin <dmitrii.bundin.a@xxxxxxxxx>
Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
---
Changes v3 -> v4:
* Split into its own patch; we don't have any out of line assembler
  files using .debug_* or .cfi_* directives that would produce
  meaningful debug info in .dwo files.

 scripts/Makefile.debug | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/scripts/Makefile.debug b/scripts/Makefile.debug
index 9f39b0130551..26d6a9d97a20 100644
--- a/scripts/Makefile.debug
+++ b/scripts/Makefile.debug
@@ -1,9 +1,7 @@
-DEBUG_CFLAGS	:=
+DEBUG_CFLAGS	:= -g
 
 ifdef CONFIG_DEBUG_INFO_SPLIT
 DEBUG_CFLAGS	+= -gsplit-dwarf
-else
-DEBUG_CFLAGS	+= -g
 endif
 
 ifndef CONFIG_AS_IS_LLVM
-- 
2.37.3.968.ga6b4b080e4-goog