msm-4.14/scripts/Makefile.extrawarn
Nathan Chancellor 49362eca81 kbuild: Move -Wenum-{compare-conditional,enum-conversion} into W=1
[ Upstream commit 75b5ab134bb5f657ef7979a59106dce0657e8d87 ]

Clang enables -Wenum-enum-conversion and -Wenum-compare-conditional
under -Wenum-conversion. A recent change in Clang strengthened these
warnings and they appear frequently in common builds, primarily due to
several instances in common headers but there are quite a few drivers
that have individual instances as well.

  include/linux/vmstat.h:508:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
    508 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
        |                            ~~~~~~~~~~~~~~~~~~~~~ ^
    509 |                            item];
        |                            ~~~~

  drivers/net/wireless/intel/iwlwifi/mvm/mac-ctxt.c:955:24: warning: conditional expression between different enumeration types ('enum iwl_mac_beacon_flags' and 'enum iwl_mac_beacon_flags_v1') [-Wenum-compare-conditional]
    955 |                 flags |= is_new_rate ? IWL_MAC_BEACON_CCK
        |                                      ^ ~~~~~~~~~~~~~~~~~~
    956 |                           : IWL_MAC_BEACON_CCK_V1;
        |                             ~~~~~~~~~~~~~~~~~~~~~
  drivers/net/wireless/intel/iwlwifi/mvm/mac-ctxt.c:1120:21: warning: conditional expression between different enumeration types ('enum iwl_mac_beacon_flags' and 'enum iwl_mac_beacon_flags_v1') [-Wenum-compare-conditional]
   1120 |                                                0) > 10 ?
        |                                                        ^
   1121 |                         IWL_MAC_BEACON_FILS :
        |                         ~~~~~~~~~~~~~~~~~~~
   1122 |                         IWL_MAC_BEACON_FILS_V1;
        |                         ~~~~~~~~~~~~~~~~~~~~~~

Doing arithmetic between or returning two different types of enums could
be a bug, so each of the instance of the warning needs to be evaluated.
Unfortunately, as mentioned above, there are many instances of this
warning in many different configurations, which can break the build when
CONFIG_WERROR is enabled.

To avoid introducing new instances of the warnings while cleaning up the
disruption for the majority of users, disable these warnings for the
default build while leaving them on for W=1 builds.

Cc: stable@vger.kernel.org
Closes: https://github.com/ClangBuiltLinux/linux/issues/2002
Link: 8c2ae42b3e
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit 39460da0515e5ef2afc67a184395daf8f97f74a1)
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
2024-05-30 09:00:38 +00:00

82 lines
3.0 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0
# ==========================================================================
#
# 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
# ==========================================================================
KBUILD_CFLAGS += $(call cc-disable-warning, packed-not-aligned)
ifeq ("$(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-option, -Wunused-const-variable)
warning-1 += $(call cc-option, -Wpacked-not-aligned)
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-2 += $(call cc-option, -Wmaybe-uninitialized)
warning-2 += $(call cc-option, -Wunused-macros)
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, sign-compare)
KBUILD_CFLAGS += $(call cc-disable-warning, format-zero-length)
KBUILD_CFLAGS += $(call cc-disable-warning, uninitialized)
KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast)
KBUILD_CFLAGS += $(call cc-disable-warning, unaligned-access)
KBUILD_CFLAGS += $(call cc-disable-warning, cast-function-type-strict)
KBUILD_CFLAGS += -Wno-enum-compare-conditional
KBUILD_CFLAGS += -Wno-enum-enum-conversion
endif
endif