Makefile.extrawarn: Move -Wunaligned-access to W=1

-Wunaligned-access is a new warning in clang that is default enabled for
arm and arm64 under certain circumstances within the clang frontend (see
LLVM commit below). On v5.17-rc2, an ARCH=arm allmodconfig build shows
1284 total/70 unique instances of this warning (most of the instances
are in header files), which is quite noisy.

To keep a normal build green through CONFIG_WERROR, only show this
warning with W=1, which will allow automated build systems to catch new
instances of the warning so that the total number can be driven down to
zero eventually since catching unaligned accesses at compile time would
be generally useful.

Cc: stable@vger.kernel.org
Link: https://github.com/llvm/llvm-project/commit/35737df4dcd28534bd3090157c224c19b501278a
Link: https://github.com/ClangBuiltLinux/linux/issues/1569
Link: https://github.com/ClangBuiltLinux/linux/issues/1576
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

This commit is contained in:

Nathan Chancellor

2022-02-02 16:05:16 -07:00

committed by

Masahiro Yamada

parent 8a4c5b2a6d

commit 1cf5f151d2

1 changed files with 1 additions and 0 deletions

									
										scripts/Makefile.extrawarn
									
		+1
		
												View File
												
				@@ -51,6 +51,7 @@ KBUILD_CFLAGS += -Wno-sign-compare

				KBUILD_CFLAGS += -Wno-format-zero-length

				KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast)

				KBUILD_CFLAGS += -Wno-tautological-constant-out-of-range-compare

				KBUILD_CFLAGS += $(call cc-disable-warning, unaligned-access)

				endif

				endif