Re: [PATCH] Documentation/kbuild/makefiles.txt: Improve description of lib-* targets

[Michal Marek <mmarek@suse.cz>]

On 2014-05-16 12:14, Sam Ravnborg wrote:
> On Wed, May 14, 2014 at 02:21:07PM -0700, Randy Dunlap wrote:
>> On 05/10/2014 10:02 PM, George Spelvin wrote:
>>> I had to ask on the mailing list, so save developers the bother of
>>> answering the question again.  (Wanna-be kernel developers might also
>>> be helped, but who cares about them?)
>>>
>>> Signed-off-by: George Spelvin <linux@horizon.com>
>>> ---
>>> As with most documentation patches, this is also an exercise in eliciting
>>> corrections by proposing a wrong answer which will be jumped on.
>>
>> Hi Michal,
>>
>> Any comments on this patch?
>>
>> Thanks.
>>
>>>
>>>  Documentation/kbuild/makefiles.txt | 23 +++++++++++++++++++++--
>>>  1 file changed, 21 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt
>>> index d567a7cc55..f6cc266163 100644
>>> --- a/Documentation/kbuild/makefiles.txt
>>> +++ b/Documentation/kbuild/makefiles.txt
>>> @@ -237,10 +237,29 @@ more details, with real examples.
>>>  	be included in a library, lib.a.
>>>  	All objects listed with lib-y are combined in a single
>>>  	library for that directory.
>>> +
>>> +	The entire kernel is then linked against these libraries,
>>> +	so the linker will include the code in the final kernel only
>>> +	if it is referenced somewhere.  Thus, lib-* goals may be
>>> +	designed with false positives.
>>> +
>>>  	Objects that are listed in obj-y and additionally listed in
>>>  	lib-y will not be included in the library, since they will
>>>  	be accessible anyway.
>>> -	For consistency, objects listed in lib-m will be included in lib.a.
>>> +
>>> +	For consistency, objects listed in lib-m will be included
>>> +	in lib.a, but this will probably not do what you want.
> 
> So maybe we should catch this and error out?

(sorry for the late reply)

That makes sense to me. Check if $(lib-m) is non-empty and throw an
error. George, do you feel like submitting a patch that does this, plus
changing the documentation to clearly state that lib-* is only meant for
built-in code?

Thanks,
Michal