path: root/Makefile
diff options
authorGustavo A. R. Silva <>2021-07-12 00:57:54 -0500
committerGustavo A. R. Silva <>2021-07-14 11:12:21 -0500
commitb7eb335e26a9c7f258c96b3962c283c379d3ede0 (patch)
tree1681cf86cd19106591630f4144806aaa643f7039 /Makefile
parent104aba8dd7dca85d82e94aba07e71994ccdaf4cf (diff)
Makefile: Enable -Wimplicit-fallthrough for Clang
With the recent fixes for fallthrough warnings, it is now possible to enable -Wimplicit-fallthrough for Clang. It's important to mention that since we have adopted the use of the pseudo-keyword macro fallthrough; we also want to avoid having more /* fall through */ comments being introduced. Notice that contrary to GCC, Clang doesn't recognize any comments as implicit fall-through markings when the -Wimplicit-fallthrough option is enabled. So, in order to avoid having more comments being introduced, we have to use the option -Wimplicit-fallthrough=5 for GCC, which similar to Clang, will cause a warning in case a code comment is intended to be used as a fall-through marking. Co-developed-by: Kees Cook <> Signed-off-by: Kees Cook <> Signed-off-by: Gustavo A. R. Silva <>
Diffstat (limited to 'Makefile')
1 files changed, 3 insertions, 6 deletions
diff --git a/Makefile b/Makefile
index c3f9bd191b89..eaa692976851 100644
--- a/Makefile
+++ b/Makefile
@@ -797,12 +797,6 @@ KBUILD_CFLAGS += -Wno-gnu
# source of a reference will be _MergedGlobals and not on of the whitelisted names.
# See modpost pattern 2
KBUILD_CFLAGS += -mno-global-merge
-# Warn about unmarked fall-throughs in switch statement.
-# Disabled for clang while comment to attribute conversion happens and
-# is discussed.
-KBUILD_CFLAGS += $(call cc-option,-Wimplicit-fallthrough,)
# These warnings generated too much noise in a regular build.
@@ -983,6 +977,9 @@ NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)
# warn about C99 declaration after statement
KBUILD_CFLAGS += -Wdeclaration-after-statement
+# Warn about unmarked fall-throughs in switch statement.
+KBUILD_CFLAGS += $(call cc-option,-Wimplicit-fallthrough=5,$(call cc-option,-Wimplicit-fallthrough,))
# Variable Length Arrays (VLAs) should not be used anywhere in the kernel