From 21f9c8a13bb2a0c24d9c6b86bc0896542a28c197 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 11 Aug 2022 08:40:01 -0700 Subject: [PATCH] Revert "Makefile.extrawarn: re-enable -Wformat for clang" This reverts commit 258fafcd0683d9ccfa524129d489948ab3ddc24c. The clang -Wformat warning is terminally broken, and the clang people can't seem to get their act together. This test program causes a warning with clang: #include int main(int argc, char **argv) { printf("%hhu\n", 'a'); } resulting in t.c:5:19: warning: format specifies type 'unsigned char' but the argument has type 'int' [-Wformat] printf("%hhu\n", 'a'); ~~~~ ^~~ %d and apparently clang people consider that a feature, because they don't want to face the reality of how either C character constants, C arithmetic, and C varargs functions work. The rest of the world just shakes their head at that kind of incompetence, and turns off -Wformat for clang again. And no, the "you should use a pointless cast to shut this up" is not a valid answer. That warning should not exist in the first place, or at least be optinal with some "-Wformat-me-harder" kind of option. [ Admittedly, there's also very little reason to *ever* use '%hh[ud]' in C, but what little reason there is is entirely about 'I want to see only the low 8 bits of the argument'. So I would suggest nobody ever use that format in the first place, but if they do, the clang behavious is simply always wrong. Because '%hhu' takes an 'int'. It's that simple. ] Reported-by: Sudip Mukherjee (Codethink) Cc: Nick Desaulniers Signed-off-by: Linus Torvalds --- scripts/Makefile.extrawarn | 1 + 1 file changed, 1 insertion(+) diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index 9bbaf7112a9b..f5f0d6f09053 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -47,6 +47,7 @@ else ifdef CONFIG_CC_IS_CLANG KBUILD_CFLAGS += -Wno-initializer-overrides +KBUILD_CFLAGS += -Wno-format KBUILD_CFLAGS += -Wno-sign-compare KBUILD_CFLAGS += -Wno-format-zero-length KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast)