scripts/Makefile.extrawarn

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