linux-kernel - Re: [PATCH 5/5] scripts/gdb: refactor rules for symlink creation

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Date:   Wed, 27 Feb 2019 13:02:11 +0000
From:   Kieran Bingham <kieran.bingham@...asonboard.com>
To:     Masahiro Yamada <yamada.masahiro@...ionext.com>
Cc:     Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>,
        Jan Kiszka <jan.kiszka@...mens.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 5/5] scripts/gdb: refactor rules for symlink creation

Hi Yamada-san,

On 27/02/2019 12:32, Masahiro Yamada wrote:
> Hi Kieran,
> 
> 
> On Wed, Feb 27, 2019 at 8:56 PM Kieran Bingham
> <kieran.bingham@...asonboard.com> wrote:
>>
>> Hi Yamada-san,
>>
>> On 19/02/2019 09:33, Masahiro Yamada wrote:
>>> gdb-scripts is not a real object, but (ab)used like a phony target.
>>>
>>> Rewrite the code in a more Kbuild-ish way. Add symlinks to extra-y
>>> and use if_changed.
>>>
>>> Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
>>> ---
>>>
>>>  scripts/gdb/linux/Makefile | 18 +++++++++++-------
>>>  1 file changed, 11 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/scripts/gdb/linux/Makefile b/scripts/gdb/linux/Makefile
>>> index 7545806..3df395a 100644
>>> --- a/scripts/gdb/linux/Makefile
>>> +++ b/scripts/gdb/linux/Makefile
>>> @@ -1,13 +1,17 @@
>>>  # SPDX-License-Identifier: GPL-2.0
>>> -always := gdb-scripts
>>>
>>> -SRCTREE := $(abspath $(srctree))
>>> -
>>> -$(obj)/gdb-scripts:
>>>  ifneq ($(KBUILD_SRC),)
>>> -     $(Q)ln -fsn $(SRCTREE)/$(obj)/*.py $(objtree)/$(obj)
>>> +
>>> +symlinks := $(patsubst $(srctree)/$(src)/%,%,$(wildcard $(srctree)/$(src)/*.py))
>>> +
>>> +quiet_cmd_symlink = SYMLINK $@
>>> +      cmd_symlink = ln -fsn $(patsubst $(obj)/%,$(abspath $(srctree))/$(src)/%,$@) $@
>>> +
>>> +extra-y += $(symlinks)
>>> +$(addprefix $(obj)/, $(symlinks)): FORCE
>>> +     $(call if_changed,symlink)
>>> +
>>>  endif
>>> -     @:
>>>
>>>  quiet_cmd_gen_constants_py = GEN     $@
>>>        cmd_gen_constants_py = \
>>> @@ -18,4 +22,4 @@ extra-y += constants.py
>>>  $(obj)/constants.py: $(src)/constants.py.in FORCE
>>>       $(call if_changed_dep,gen_constants_py)
>>>
>>> -clean-files := *.pyc *.pyo $(if $(KBUILD_SRC),*.py)
>>> +clean-files := *.pyc *.pyo
>>
>> Perhaps this answers my earlier question.
>> I guess the extra-y hook is somehow handling the clean up of these files?
>>
>> Aha - yes, I've just found it in
>>
>> Documentation/kbuild/makefiles.txt:
>>> === 5 Kbuild clean infrastructure
>>> ...
>>> Kbuild knows targets listed in $(hostprogs-y), $(hostprogs-m), $(always), $(extra-y) and $(targets). They are all deleted during "make clean".
>>
>> Perfect, so this is much better.
> 
> Exactly.
> 
> If you are interested in the real code,
> see scripts/Makefile.clean
> 
> 
> __clean-files   := $(extra-y) $(extra-m) $(extra-)       \
>                    $(always) $(targets) $(clean-files)   \
>                    $(hostprogs-y) $(hostprogs-m) $(hostprogs-) \
>                    $(hostlibs-y) $(hostlibs-m) $(hostlibs-) \
>                    $(hostcxxlibs-y) $(hostcxxlibs-m)
> 

Thank you - that makes it very clear.

Thanks again for you work :)

--
Kieran


> 
>> Reviewed-by: Kieran Bingham <kieran.bingham@...asonboard.com>
>>
>> --
>> Regards
>> --
>> Kieran
> 
> 
> 

-- 
Regards
--
Kieran