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 += $(call cc-option, -Wstringop-truncation) 35# The following turn off the warnings enabled by -Wextra 36KBUILD_CFLAGS += -Wno-missing-field-initializers 37KBUILD_CFLAGS += -Wno-sign-compare 38KBUILD_CFLAGS += -Wno-type-limits 39KBUILD_CFLAGS += -Wno-shift-negative-value 40 41KBUILD_CPPFLAGS += -Wundef 42KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN1 43 44else 45 46# Some diagnostics enabled by default are noisy. 47# Suppress them by using -Wno... except for W=1. 48 49ifdef CONFIG_CC_IS_CLANG 50KBUILD_CFLAGS += -Wno-initializer-overrides 51# Clang before clang-16 would warn on default argument promotions. 52ifneq ($(call clang-min-version, 160000),y) 53# Disable -Wformat 54KBUILD_CFLAGS += -Wno-format 55# Then re-enable flags that were part of the -Wformat group that aren't 56# problematic. 57KBUILD_CFLAGS += -Wformat-extra-args -Wformat-invalid-specifier 58KBUILD_CFLAGS += -Wformat-zero-length -Wnonnull 59# Requires clang-12+. 60ifeq ($(call clang-min-version, 120000),y) 61KBUILD_CFLAGS += -Wformat-insufficient-args 62endif 63endif 64KBUILD_CFLAGS += -Wno-sign-compare 65KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast) 66KBUILD_CFLAGS += -Wno-tautological-constant-out-of-range-compare 67KBUILD_CFLAGS += $(call cc-disable-warning, unaligned-access) 68KBUILD_CFLAGS += $(call cc-disable-warning, cast-function-type-strict) 69endif 70 71endif 72 73# 74# W=2 - warnings which occur quite often but may still be relevant 75# 76ifneq ($(findstring 2, $(KBUILD_EXTRA_WARN)),) 77 78KBUILD_CFLAGS += -Wdisabled-optimization 79KBUILD_CFLAGS += -Wshadow 80KBUILD_CFLAGS += $(call cc-option, -Wlogical-op) 81KBUILD_CFLAGS += -Wmissing-field-initializers 82KBUILD_CFLAGS += -Wtype-limits 83KBUILD_CFLAGS += $(call cc-option, -Wmaybe-uninitialized) 84KBUILD_CFLAGS += $(call cc-option, -Wunused-macros) 85 86KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN2 87 88endif 89 90# 91# W=3 - more obscure warnings, can most likely be ignored 92# 93ifneq ($(findstring 3, $(KBUILD_EXTRA_WARN)),) 94 95KBUILD_CFLAGS += -Wbad-function-cast 96KBUILD_CFLAGS += -Wcast-align 97KBUILD_CFLAGS += -Wcast-qual 98KBUILD_CFLAGS += -Wconversion 99KBUILD_CFLAGS += -Wpacked 100KBUILD_CFLAGS += -Wpadded 101KBUILD_CFLAGS += -Wpointer-arith 102KBUILD_CFLAGS += -Wredundant-decls 103KBUILD_CFLAGS += -Wsign-compare 104KBUILD_CFLAGS += -Wswitch-default 105KBUILD_CFLAGS += $(call cc-option, -Wpacked-bitfield-compat) 106 107KBUILD_CPPFLAGS += -DKBUILD_EXTRA_WARN3 108 109endif 110 111# 112# W=e - error out on warnings 113# 114ifneq ($(findstring e, $(KBUILD_EXTRA_WARN)),) 115 116KBUILD_CFLAGS += -Werror 117 118endif 119