From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Warren <swarren@wwwdotorg.org>
Date: Wed, 19 Feb 2014 09:36:14 -0700
Subject: [U-Boot] [PATCH] kbuild,tegra124: add dummy obj- for Kbuild
In-Reply-To: <20140219154659.5f1ba763@lilith>
References: <1392816403-9101-1-git-send-email-yamada.m@jp.panasonic.com>
	<20140219154659.5f1ba763@lilith>
Message-ID: <5304DD7E.7070104@wwwdotorg.org>
List-Id: <u-boot.lists.denx.de>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
To: u-boot@lists.denx.de

On 02/19/2014 07:46 AM, Albert ARIBAUD wrote:
> Hi Masahiro,
> 
> On Wed, 19 Feb 2014 22:26:43 +0900, Masahiro Yamada
> <yamada.m@jp.panasonic.com> wrote:
> 
>> In Kbuild, every makefile must have non-empty obj- or obj-y.
>> Otherwise, built-in.o will not be created and the link stage
>> will fail.
...
>> diff --git a/arch/arm/cpu/armv7/tegra124/Makefile b/arch/arm/cpu/armv7/tegra124/Makefile
...
>> +# necessary to create built-in.o
>> +obj- := __dummy__.o

obj- or obj-y?

Adding something to obj-, which presumably isn't used at all, seems very
odd.

> Is there really no other way than to specify an unexisting __dummy__.o
> in order to build a useless built-in.o?

I haven't looked at Kbuild at all, but in the build systems I've
written, for each sub-directory makefile that was included, the
makefiles would include a "pre-makefile" first and a "post-makefile"
after. The "post-makefile" could easily do something like:

ifeq ($(obj-y),)
    obg-y := __dummy__.o
endif