lkml.org 
[lkml]   [2019]   [Aug]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
Subject[PATCH] kbuild: Require W=1 for -Wimplicit-fallthrough with clang
From
Clang is updating to support -Wimplicit-fallthrough on C
https://reviews.llvm.org/D64838. Since clang does not
support the comment version of fallthrough annotations
this update causes an additional 50k warnings. Most
of these warnings (>49k) are duplicates from header files.

This patch is intended to be reverted after the warnings
have been cleaned up.

Signed-off-by: Nathan Huckleberry <nhuck@google.com>
---
Makefile | 4 ++++
scripts/Makefile.extrawarn | 3 +++
2 files changed, 7 insertions(+)

diff --git a/Makefile b/Makefile
index 1b23f95db176..93b9744e66a2 100644
--- a/Makefile
+++ b/Makefile
@@ -846,7 +846,11 @@ NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)
KBUILD_CFLAGS += -Wdeclaration-after-statement

# Warn about unmarked fall-throughs in switch statement.
+# If the compiler is clang, this warning is only enabled if W=1 in
+# Makefile.extrawarn
+ifndef CONFIG_CC_IS_CLANG
KBUILD_CFLAGS += $(call cc-option,-Wimplicit-fallthrough,)
+endif

# Variable Length Arrays (VLAs) should not be used anywhere in the kernel
KBUILD_CFLAGS += -Wvla
diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
index a74ce2e3c33e..e12359d69bb7 100644
--- a/scripts/Makefile.extrawarn
+++ b/scripts/Makefile.extrawarn
@@ -30,6 +30,9 @@ warning-1 += $(call cc-option, -Wunused-but-set-variable)
warning-1 += $(call cc-option, -Wunused-const-variable)
warning-1 += $(call cc-option, -Wpacked-not-aligned)
warning-1 += $(call cc-option, -Wstringop-truncation)
+ifdef CONFIG_CC_IS_CLANG
+KBUILD_CFLAGS += $(call cc-option,-Wimplicit-fallthrough,)
+endif
# The following turn off the warnings enabled by -Wextra
warning-1 += -Wno-missing-field-initializers
warning-1 += -Wno-sign-compare
--
2.23.0.rc1.153.gdeed80330f-goog
\
 
 \ /
  Last update: 2019-08-15 20:22    [W:0.077 / U:0.376 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site