linux-stable/scripts/Makefile.extrawarn
Lee Jones 7599ea8b4e kbuild: Demote 'sign-compare' warning to W=2
Ideally, a kernel compile with W=1 enabled should complete cleanly;
however, when we run one currently we are presented with ~25k warnings.
'sign-compare' accounts for ~22k of those ~25k.

In this patch we're demoting 'sign-compare' warnings to W=2, with a view
to fixing the remaining 3k W=1 warnings required for a clean build.

Arnd adds:
  "As per our discussion, I'd add that this was inadvertedly introduced
   by Behan when he moved the clang specific warnings into an ifdef block
   and did not notice that -Wsign-compare was interpreted by both gcc
   and clang.

   Earlier, it was introduced in just the same way by Jan-Simon as part
   of 3d3d6b8474 ("kbuild: LLVMLinux: Adapt warnings for compilation
   with clang")."

Acked-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 26ea6bb1fe ("kbuild, LLVMLinux: Supress warnings unless W=1-3")
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Michal Marek <mmarek@suse.com>
2016-01-12 16:07:03 +01:00

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# ==========================================================================
#
# make W=... settings
#
# W=1 - warnings that may be relevant and does not occur too often
# W=2 - warnings that occur quite often but may still be relevant
# W=3 - the more obscure warnings, can most likely be ignored
#
# $(call cc-option, -W...) handles gcc -W.. options which
# are not supported by all versions of the compiler
# ==========================================================================
ifeq ("$(origin W)", "command line")
export KBUILD_ENABLE_EXTRA_GCC_CHECKS := $(W)
endif
ifdef KBUILD_ENABLE_EXTRA_GCC_CHECKS
warning- := $(empty)
warning-1 := -Wextra -Wunused -Wno-unused-parameter
warning-1 += -Wmissing-declarations
warning-1 += -Wmissing-format-attribute
warning-1 += $(call cc-option, -Wmissing-prototypes)
warning-1 += -Wold-style-definition
warning-1 += $(call cc-option, -Wmissing-include-dirs)
warning-1 += $(call cc-option, -Wunused-but-set-variable)
warning-1 += $(call cc-disable-warning, missing-field-initializers)
warning-1 += $(call cc-disable-warning, sign-compare)
warning-2 := -Waggregate-return
warning-2 += -Wcast-align
warning-2 += -Wdisabled-optimization
warning-2 += -Wnested-externs
warning-2 += -Wshadow
warning-2 += $(call cc-option, -Wlogical-op)
warning-2 += $(call cc-option, -Wmissing-field-initializers)
warning-2 += $(call cc-option, -Wsign-compare)
warning-3 := -Wbad-function-cast
warning-3 += -Wcast-qual
warning-3 += -Wconversion
warning-3 += -Wpacked
warning-3 += -Wpadded
warning-3 += -Wpointer-arith
warning-3 += -Wredundant-decls
warning-3 += -Wswitch-default
warning-3 += $(call cc-option, -Wpacked-bitfield-compat)
warning-3 += $(call cc-option, -Wvla)
warning := $(warning-$(findstring 1, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
warning += $(warning-$(findstring 2, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
warning += $(warning-$(findstring 3, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
ifeq ("$(strip $(warning))","")
$(error W=$(KBUILD_ENABLE_EXTRA_GCC_CHECKS) is unknown)
endif
KBUILD_CFLAGS += $(warning)
else
ifeq ($(cc-name),clang)
KBUILD_CFLAGS += $(call cc-disable-warning, initializer-overrides)
KBUILD_CFLAGS += $(call cc-disable-warning, unused-value)
KBUILD_CFLAGS += $(call cc-disable-warning, format)
KBUILD_CFLAGS += $(call cc-disable-warning, unknown-warning-option)
KBUILD_CFLAGS += $(call cc-disable-warning, sign-compare)
KBUILD_CFLAGS += $(call cc-disable-warning, format-zero-length)
KBUILD_CFLAGS += $(call cc-disable-warning, uninitialized)
endif
endif