From 28bc20dccadc610c56e27255aeef2938141a0cd3 Mon Sep 17 00:00:00 2001 From: Sam Ravnborg Date: Wed, 27 Apr 2011 22:15:27 +0200 Subject: [PATCH] kbuild: implement several W= levels Building a kernel with "make W=1" produces far too much noise to be useful. Divide the warning options in three groups: 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 When building the whole kernel, those levels produce: W=1 - 4859 warnings W=2 - 1394 warnings W=3 - 86666 warnings respectively. Warnings have been counted with Geert's script at http://www.kernel.org/pub/linux/kernel/people/geert/linux-log/linux-log-summary.pl Many warnings occur from .h files so fixing one file may have a nice effect on the total number of warnings. With these changes I am actually tempted to try W=1 now and then. Previously there was just too much noise. Borislav: - make the W= levels exclusive - move very noisy and making little sense for the kernel warnings to W=3 - drop -Woverlength-strings due to useless warning message - copy explanatory text for the different warning levels to 'make help' - recount warnings per level Signed-off-by: Sam Ravnborg Signed-off-by: Borislav Petkov Cc: Dave Jones Cc: Geert Uytterhoeven Signed-off-by: Michal Marek --- Makefile | 8 ++++-- scripts/Makefile.build | 65 ++++++++++++++++++++++++------------------ 2 files changed, 44 insertions(+), 29 deletions(-) diff --git a/Makefile b/Makefile index d7c42319fe1e..d43429f4ced8 100644 --- a/Makefile +++ b/Makefile @@ -103,7 +103,7 @@ ifeq ("$(origin O)", "command line") endif ifeq ("$(origin W)", "command line") - export KBUILD_ENABLE_EXTRA_GCC_CHECKS := 1 + export KBUILD_ENABLE_EXTRA_GCC_CHECKS := $(W) endif # That's our default target when none is given on the command line @@ -1274,7 +1274,11 @@ 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 ' make W=n [targets] Enable extra gcc checks, n=1,2,3 where' + @echo ' 1: warnings which may be relevant and do not occur too often' + @echo ' 2: warnings which occur quite often but may still be relevant' + @echo ' 3: more obscure warnings, can most likely be ignored' + @echo '' @echo 'Execute "make" or "make all" to build all targets marked with [*] ' @echo 'For further info see the ./README file' diff --git a/scripts/Makefile.build b/scripts/Makefile.build index e1244ef308ce..9c0c48127946 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -51,36 +51,47 @@ ifeq ($(KBUILD_NOPEDANTIC),) endif # -# make W=1 settings +# make W=... settings # -# $(call cc-option... ) handles gcc -W.. options which +# 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 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) +warning-1 := -Wextra -Wunused -Wno-unused-parameter +warning-1 += -Wmissing-declarations +warning-1 += -Wmissing-format-attribute +warning-1 += -Wmissing-prototypes +warning-1 += -Wold-style-definition +warning-1 += $(call cc-option, -Wmissing-include-dirs) + +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-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 := $(warning-$(KBUILD_ENABLE_EXTRA_GCC_CHECKS)) + +ifeq ("$(warning)","") + $(error W=$(KBUILD_ENABLE_EXTRA_GCC_CHECKS) is unknown) +endif + +KBUILD_CFLAGS += $(warning) endif include scripts/Makefile.lib