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authorNathan Chancellor <nathan@kernel.org>2021-09-16 11:40:17 -0700
committerMasahiro Yamada <masahiroy@kernel.org>2021-09-19 10:55:18 +0900
commit0664684e1ebd7875e120d0cecd525bac4805f8ed (patch)
tree64d1b995007dfb9175c8f369519bcaa971c557c3
parent7fa6a2746616c8de4c40b748c2bb0656e00624ff (diff)
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>
-rw-r--r--scripts/Makefile.clang5
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