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Date: Fri, 29 Apr 2011 14:13:11 -0400
Message-ID: <BANLkTimsNF=OeaLSnSt2gFdDaAbJ6tMFng@mail.gmail.com>
Subject: Re: [PATCH] kbuild: Allow to combine multiple W= levels
From: Arnaud Lacombe <lacombar@gmail.com>
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To: Michal Marek <mmarek@suse.cz>
Cc: Valdis.Kletnieks@vt.edu, bp@alien8.de, sam@ravnborg.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, davej@redhat.com

Hi,

On Fri, Apr 29, 2011 at 9:31 AM, Michal Marek <mmarek@suse.cz> wrote:
> Add support for make W=12, make W=123 and so on, to enable warnings from
> multiple W= levels. Normally, make W=<level> does not include warnings
> from the previous level.
>
> Signed-off-by: Michal Marek <mmarek@suse.cz>
> ---
>  scripts/Makefile.build |    8 ++++++--
>  1 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> index 9c0c481..28cef2a 100644
> --- a/scripts/Makefile.build
> +++ b/scripts/Makefile.build
> @@ -60,6 +60,8 @@ endif
>  # $(call cc-option, -W...) handles gcc -W.. options which
>  # are not supported by all versions of the compiler
>  ifdef KBUILD_ENABLE_EXTRA_GCC_CHECKS
> +warning-  := $(empty)
> +
>  warning-1 := -Wextra -Wunused -Wno-unused-parameter
>  warning-1 += -Wmissing-declarations
>  warning-1 += -Wmissing-format-attribute
> @@ -85,9 +87,11 @@ 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))
> +warning := $(warning-$(findstring 1, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
> +warning += $(warning-$(findstring 2, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
> +warning += $(warning-$(findstring 3, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)))
>
I do not really like that, it would mean that W=123, W=321, W=231 and
W=132 would lead to the same result. What about a comma separated
string, ala:

LEVELS=1,2,3,4

comma:= ,
empty:=
space:= $(empty) $(empty)

warning-1:= a
warning-2:= b
warning-3:= c
warning-4:= d

all:
        echo $(foreach level, $(subst ${comma},${space},${LEVELS},
${warning}), ${warning-${level}})

It has the advantage to scale up without adding new code.

 - Arnaud

> -ifeq ("$(warning)","")
> +ifeq ("$(strip $(warning))","")
>         $(error W=$(KBUILD_ENABLE_EXTRA_GCC_CHECKS) is unknown)
>  endif
>
> --
> 1.7.4.1
>
> --
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