Commit 4a5838ad authored by Borislav Petkov's avatar Borislav Petkov Committed by Michal Marek

kbuild: Add extra gcc checks

Add a 'W=1' Makefile switch which adds additional checking per build
object.

The idea behind this option is targeted at developers who, in the
process of writing their code, want to do the occasional

make W=1 [target.o]

and let gcc do more extensive code checking for them. Then, they
could eyeball the output for valid gcc warnings about various
bugs/discrepancies which are not reported during the normal build
process.

For more background information and a use case, read through this
thread: http://marc.info/?l=kernel-janitors&m=129802065918147&w=2

Cc: Michal Marek <mmarek@suse.cz>
Cc: linux-kbuild@vger.kernel.org
Acked-by: default avatarSam Ravnborg <sam@ravnborg.org>
Acked-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarBorislav Petkov <bp@alien8.de>
Signed-off-by: default avatarMichal Marek <mmarek@suse.cz>
parent de933bd8
......@@ -196,3 +196,8 @@ to be included in the databases, separated by blank space. E.g.:
To get all available archs you can also specify all. E.g.:
$ make ALLSOURCE_ARCHS=all tags
KBUILD_ENABLE_EXTRA_GCC_CHECKS
--------------------------------------------------
If enabled over the make command line with "W=1", it turns on additional
gcc -W... options for more extensive build-time checking.
......@@ -102,6 +102,10 @@ ifeq ("$(origin O)", "command line")
KBUILD_OUTPUT := $(O)
endif
ifeq ("$(origin W)", "command line")
export KBUILD_ENABLE_EXTRA_GCC_CHECKS := 1
endif
# That's our default target when none is given on the command line
PHONY := _all
_all:
......@@ -1262,6 +1266,7 @@ help:
@echo ' make O=dir [targets] Locate all output files in "dir", including .config'
@echo ' make C=1 [targets] Check all c source with $$CHECK (sparse by default)'
@echo ' make C=2 [targets] Force check of all c source with $$CHECK'
@echo ' make W=1 [targets] Enable extra gcc checks'
@echo ''
@echo 'Execute "make" or "make all" to build all targets marked with [*] '
@echo 'For further info see the ./README file'
......
......@@ -49,6 +49,40 @@ ifeq ($(KBUILD_NOPEDANTIC),)
$(error CFLAGS was changed in "$(kbuild-file)". Fix it to use EXTRA_CFLAGS)
endif
endif
#
# make W=1 settings
#
# $(call cc-option... ) handles gcc -W.. options which
# are not supported by all versions of the compiler
ifdef KBUILD_ENABLE_EXTRA_GCC_CHECKS
KBUILD_EXTRA_WARNINGS := -Wextra
KBUILD_EXTRA_WARNINGS += -Wunused -Wno-unused-parameter
KBUILD_EXTRA_WARNINGS += -Waggregate-return
KBUILD_EXTRA_WARNINGS += -Wbad-function-cast
KBUILD_EXTRA_WARNINGS += -Wcast-qual
KBUILD_EXTRA_WARNINGS += -Wcast-align
KBUILD_EXTRA_WARNINGS += -Wconversion
KBUILD_EXTRA_WARNINGS += -Wdisabled-optimization
KBUILD_EXTRA_WARNINGS += -Wlogical-op
KBUILD_EXTRA_WARNINGS += -Wmissing-declarations
KBUILD_EXTRA_WARNINGS += -Wmissing-format-attribute
KBUILD_EXTRA_WARNINGS += $(call cc-option, -Wmissing-include-dirs,)
KBUILD_EXTRA_WARNINGS += -Wmissing-prototypes
KBUILD_EXTRA_WARNINGS += -Wnested-externs
KBUILD_EXTRA_WARNINGS += -Wold-style-definition
KBUILD_EXTRA_WARNINGS += $(call cc-option, -Woverlength-strings,)
KBUILD_EXTRA_WARNINGS += -Wpacked
KBUILD_EXTRA_WARNINGS += -Wpacked-bitfield-compat
KBUILD_EXTRA_WARNINGS += -Wpadded
KBUILD_EXTRA_WARNINGS += -Wpointer-arith
KBUILD_EXTRA_WARNINGS += -Wredundant-decls
KBUILD_EXTRA_WARNINGS += -Wshadow
KBUILD_EXTRA_WARNINGS += -Wswitch-default
KBUILD_EXTRA_WARNINGS += $(call cc-option, -Wvla,)
KBUILD_CFLAGS += $(KBUILD_EXTRA_WARNINGS)
endif
include scripts/Makefile.lib
ifdef host-progs
......@@ -403,7 +437,6 @@ ifneq ($(cmd_files),)
include $(cmd_files)
endif
# Declare the contents of the .PHONY variable as phony. We keep that
# information in a variable se we can use it in if_changed and friends.
......
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