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| author | Nathan Chancellor <nathan@kernel.org> | 2021-09-16 11:40:17 -0700 |
|---|---|---|
| committer | Masahiro Yamada <masahiroy@kernel.org> | 2021-09-19 10:55:18 +0900 |
| commit | 0664684e1ebd7875e120d0cecd525bac4805f8ed (patch) | |
| tree | 64d1b995007dfb9175c8f369519bcaa971c557c3 /scripts/Makefile.clang | |
| parent | 7fa6a2746616c8de4c40b748c2bb0656e00624ff (diff) | |
| download | lwn-0664684e1ebd7875e120d0cecd525bac4805f8ed.tar.gz lwn-0664684e1ebd7875e120d0cecd525bac4805f8ed.zip | |
kbuild: Add -Werror=ignored-optimization-argument to CLANG_FLAGS
Similar to commit 589834b3a009 ("kbuild: Add
-Werror=unknown-warning-option to CLANG_FLAGS").
Clang ignores certain GCC flags that it has not implemented, only
emitting a warning:
$ echo | clang -fsyntax-only -falign-jumps -x c -
clang-14: warning: optimization flag '-falign-jumps' is not supported
[-Wignored-optimization-argument]
When one of these flags gets added to KBUILD_CFLAGS unconditionally, all
subsequent cc-{disable-warning,option} calls fail because -Werror was
added to these invocations to turn the above warning and the equivalent
-W flag warning into errors.
To catch the presence of these flags earlier, turn
-Wignored-optimization-argument into an error so that the flags can
either be implemented or ignored via cc-option and there are no more
weird errors.
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Diffstat (limited to 'scripts/Makefile.clang')
| -rw-r--r-- | scripts/Makefile.clang | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/scripts/Makefile.clang b/scripts/Makefile.clang index 4cce8fd0779c..51fc23e2e9e5 100644 --- a/scripts/Makefile.clang +++ b/scripts/Makefile.clang @@ -29,7 +29,12 @@ CLANG_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE)) else CLANG_FLAGS += -fintegrated-as endif +# By default, clang only warns when it encounters an unknown warning flag or +# certain optimization flags it knows it has not implemented. +# Make it behave more like gcc by erroring when these flags are encountered +# so they can be implemented or wrapped in cc-option. CLANG_FLAGS += -Werror=unknown-warning-option +CLANG_FLAGS += -Werror=ignored-optimization-argument KBUILD_CFLAGS += $(CLANG_FLAGS) KBUILD_AFLAGS += $(CLANG_FLAGS) export CLANG_FLAGS |