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* [PATCH 1/2] kbuild: move -Werror from KBUILD_CFLAGS to KBUILD_CPPFLAGS
@ 2022-09-05  8:36 Masahiro Yamada
  2022-09-05  8:36 ` [PATCH 2/2] kbuild: move -Wundef " Masahiro Yamada
  2022-09-07  5:05 ` [PATCH 1/2] kbuild: move -Werror " Nick Desaulniers
  0 siblings, 2 replies; 10+ messages in thread
From: Masahiro Yamada @ 2022-09-05  8:36 UTC (permalink / raw)
  To: linux-kbuild
  Cc: Masahiro Yamada, Michal Marek, Nick Desaulniers, linux-kernel

CONFIG_WERROR makes warnings into errors, but it only happens for *.c
files because -Werror is added to KBUILD_CFLAGS.

For example, you can put a #warning directive in any preprocessed
source file:

    #warning "blah blah ..."

If it is placed in a *.c file, it emits a warning by default, and it
is promoted to an error when CONFIG_WERROR is enabled:

    error: #warning "blah blah ..." [-Werror=cpp]

If it is placed in a *.S file, it is still a warning.

Move it to KBUILD_CPPFLAGS, so it works in the same way for *.c,
*.S, *.lds.S or whatever needs preprocessing.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 Makefile | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index ebcb75442d7f..027d9163eff6 100644
--- a/Makefile
+++ b/Makefile
@@ -788,7 +788,8 @@ stackp-flags-$(CONFIG_STACKPROTECTOR_STRONG)      := -fstack-protector-strong
 
 KBUILD_CFLAGS += $(stackp-flags-y)
 
-KBUILD_CFLAGS-$(CONFIG_WERROR) += -Werror
+KBUILD_CPPFLAGS-$(CONFIG_WERROR) += -Werror
+KBUILD_CPPFLAGS += $(KBUILD_CPPFLAGS-y)
 KBUILD_CFLAGS-$(CONFIG_CC_NO_ARRAY_BOUNDS) += -Wno-array-bounds
 KBUILD_CFLAGS += $(KBUILD_CFLAGS-y) $(CONFIG_CC_IMPLICIT_FALLTHROUGH)
 
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [PATCH 1/2] kbuild: move -Werror from KBUILD_CFLAGS to KBUILD_CPPFLAGS
@ 2022-12-06  4:07 Masahiro Yamada
  2022-12-09 17:47 ` Nathan Chancellor
  0 siblings, 1 reply; 10+ messages in thread
From: Masahiro Yamada @ 2022-12-06  4:07 UTC (permalink / raw)
  To: linux-kbuild
  Cc: linux-kernel, Masahiro Yamada, Nick Desaulniers,
	Nathan Chancellor, Nicolas Schier

CONFIG_WERROR turns warnings into errors, which happens only for *.c
files because -Werror is added to KBUILD_CFLAGS.

Adding it to KBUILD_CPPFLAGS makes more sense because preprocessors
understand the -Werror option.

For example, you can put a #warning directive in any preprocessed code.

    warning: #warning "this is a warning message" [-Wcpp]

If -Werror is added, it is promoted to an error.

    error: #warning "this is a warning message" [-Werror=cpp]

This commit moves -Werror to KBUILD_CPPFLAGS so it works in the same way
for *.c, *.S, *.lds.S or whatever needs preprocessing.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
---

 Makefile | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 53fa1a9fba8a..f84b57910667 100644
--- a/Makefile
+++ b/Makefile
@@ -869,7 +869,8 @@ stackp-flags-$(CONFIG_STACKPROTECTOR_STRONG)      := -fstack-protector-strong
 
 KBUILD_CFLAGS += $(stackp-flags-y)
 
-KBUILD_CFLAGS-$(CONFIG_WERROR) += -Werror
+KBUILD_CPPFLAGS-$(CONFIG_WERROR) += -Werror
+KBUILD_CPPFLAGS += $(KBUILD_CPPFLAGS-y)
 KBUILD_CFLAGS-$(CONFIG_CC_NO_ARRAY_BOUNDS) += -Wno-array-bounds
 
 KBUILD_RUSTFLAGS-$(CONFIG_WERROR) += -Dwarnings
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread
end of thread, other threads:[~2022-12-09 17:47 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-09-05  8:36 [PATCH 1/2] kbuild: move -Werror from KBUILD_CFLAGS to KBUILD_CPPFLAGS Masahiro Yamada
2022-09-05  8:36 ` [PATCH 2/2] kbuild: move -Wundef " Masahiro Yamada
2022-09-05 14:22   ` kernel test robot
2022-09-05 15:48   ` kernel test robot
2022-09-05 16:01     ` Masahiro Yamada
2022-09-05 16:01       ` Masahiro Yamada
2022-09-12  9:56   ` kernel test robot
2022-09-07  5:05 ` [PATCH 1/2] kbuild: move -Werror " Nick Desaulniers
2022-12-06  4:07 Masahiro Yamada
2022-12-09 17:47 ` Nathan Chancellor

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