1# SPDX-License-Identifier: GPL-2.0 2# ========================================================================== 3# make W=... settings 4# 5# There are four warning groups enabled by W=1, W=2, W=3, and W=e 6# They are independent, and can be combined like W=12 or W=123e. 7# ========================================================================== 8 9KBUILD_CFLAGS += $(call cc-disable-warning, packed-not-aligned) 10 11# backward compatibility 12KBUILD_EXTRA_WARN ?= $(KBUILD_ENABLE_EXTRA_GCC_CHECKS) 13 14ifeq ("$(origin W)", "command line") 15 KBUILD_EXTRA_WARN := $(W) 16endif 17 18export KBUILD_EXTRA_WARN 19 20# 21# W=1 - warnings which may be relevant and do not occur too often 22# 23ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),) 24 25KBUILD_CFLAGS += -Wextra -Wunused -Wno-unused-parameter 26KBUILD_CFLAGS += -Wmissing-declarations 27KBUILD_CFLAGS += -Wmissing-format-attribute 28KBUILD_CFLAGS += -Wmissing-prototypes 29KBUILD_CFLAGS += -Wold-style-definition 30KBUILD_CFLAGS += -Wmissing-include-dirs 31KBUILD_CFLAGS += $(call cc-option, -Wunused-but-set-variable) 32KBUILD_CFLAGS += $(call cc-option, -Wunused-const-variable) 33KBUILD_CFLAGS += $(call cc-option, -Wpacked-not-aligned) 34KBUILD_CFLAGS += $(call cc-option, -Wstringop-truncation) 35# The following turn off the warnings enabled by -Wextra 36KBUILD_CFLAGS += -Wno-missing-field-initializers 37KBUILD_CFLAGS += -Wno-sign-compare 38KBUILD_CFLAGS += -Wno-type-limits 39KBUILD_CFLAGS += -Wno-shift-negative-value 40 41KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN1 42 43else 44 45# Some diagnostics enabled by default are noisy. 46# Suppress them by using -Wno... except for W=1. 47 48ifdef CONFIG_CC_IS_CLANG 49KBUILD_CFLAGS += -Wno-initializer-overrides 50# Clang before clang-16 would warn on default argument promotions. 51ifneq ($(call clang-min-version, 160000),y) 52# Disable -Wformat 53KBUILD_CFLAGS += -Wno-format 54# Then re-enable flags that were part of the -Wformat group that aren't 55# problematic. 56KBUILD_CFLAGS += -Wformat-extra-args -Wformat-invalid-specifier 57KBUILD_CFLAGS += -Wformat-zero-length -Wnonnull 58# Requires clang-12+. 59ifeq ($(call clang-min-version, 120000),y) 60KBUILD_CFLAGS += -Wformat-insufficient-args 61endif 62endif 63KBUILD_CFLAGS += -Wno-sign-compare 64KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast) 65KBUILD_CFLAGS += -Wno-tautological-constant-out-of-range-compare 66KBUILD_CFLAGS += $(call cc-disable-warning, unaligned-access) 67KBUILD_CFLAGS += $(call cc-disable-warning, cast-function-type-strict) 68endif 69 70endif 71 72# 73# W=2 - warnings which occur quite often but may still be relevant 74# 75ifneq ($(findstring 2, $(KBUILD_EXTRA_WARN)),) 76 77KBUILD_CFLAGS += -Wdisabled-optimization 78KBUILD_CFLAGS += -Wshadow 79KBUILD_CFLAGS += $(call cc-option, -Wlogical-op) 80KBUILD_CFLAGS += -Wmissing-field-initializers 81KBUILD_CFLAGS += -Wtype-limits 82KBUILD_CFLAGS += $(call cc-option, -Wmaybe-uninitialized) 83KBUILD_CFLAGS += $(call cc-option, -Wunused-macros) 84 85KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN2 86 87endif 88 89# 90# W=3 - more obscure warnings, can most likely be ignored 91# 92ifneq ($(findstring 3, $(KBUILD_EXTRA_WARN)),) 93 94KBUILD_CFLAGS += -Wbad-function-cast 95KBUILD_CFLAGS += -Wcast-align 96KBUILD_CFLAGS += -Wcast-qual 97KBUILD_CFLAGS += -Wconversion 98KBUILD_CFLAGS += -Wpacked 99KBUILD_CFLAGS += -Wpadded 100KBUILD_CFLAGS += -Wpointer-arith 101KBUILD_CFLAGS += -Wredundant-decls 102KBUILD_CFLAGS += -Wsign-compare 103KBUILD_CFLAGS += -Wswitch-default 104KBUILD_CFLAGS += $(call cc-option, -Wpacked-bitfield-compat) 105 106KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN3 107 108endif 109 110# 111# W=e - error out on warnings 112# 113ifneq ($(findstring e, $(KBUILD_EXTRA_WARN)),) 114 115KBUILD_CFLAGS += -Werror 116 117endif 118