Re: [uml-devel] [PATCH] Remove remaining references of CONFIG_GENERIC_TIME

[Arnaud L. <lac...@gm...>]

Hi,

On Mon, Aug 1, 2011 at 12:08 PM, Arnaud Lacombe <lac...@gm...> wrote:
> Hi,
>
> On Mon, Aug 1, 2011 at 11:15 AM, Kyle Moffett <ky...@mo...> wrote:
>> On Mon, Aug 1, 2011 at 11:04, Arnaud Lacombe <lac...@gm...> wrote:
>>> Hi,
>>>
>>> On Mon, Aug 1, 2011 at 7:27 AM, Geert Uytterhoeven <ge...@li...> wrote:
>>>> On Mon, Aug 1, 2011 at 12:14, Russell King - ARM Linux
>>>>>>[...]
>>>>>>
>>>>>> Doesn't kconf error out when trying to select a non-existent symbol?
>>>>>
>>>>> Nope.
>>>>
>>>> You're right. So that's a bug.
>>>>
>>> depends on what you are trying to achieve and what the problem is.
>>>
>>> Internally kconfig will create a dummy symbol when it encounter a
>>> missing symbol so that arch/arm/Kconfig can reference a symbol which
>>> will be fully defined later on. I do not think you want to forward
>>> decl all the symbol which can be used. That'd be a mess. That said, we
>>> can come with a form of symbol deprecation that would error-out when
>>> used.
>>
>> Would it be possible instead to make Kconfig go through all the symbols
>> after everything is processed and identify any remaining "dummy symbols"
>> which were not actually declared anywhere?
>>
> this is software, everything is possible.
>
>> Right now if you typo a "select" statement you get no warnings that you
>> are selecting something that does not exist, which is probably a cause
>> of many kinds of errors beyond this particular one.
>>
> d'oh! ... I'm not sure we want that. Dummy symbol are heavily used
> internally, a trivial implementation[0] triggered:
>
> % make REGENERATE_PARSERS=y alldefconfig 2>&1 | grep 'defined without
> type' | wc -l
> 817
>
> Moreover, this approach is deemed to fail. The current symbol
> namespace is tied to an arch, so whenever you do:
>
> arch/arm/Kconfig:
> config FOO
>    bool
>
> config BAZ
>    bool
>
> drivers/cpufreq/Kconfig
> config BAR
>    depends on ARM && FOO
>    select BAZ
>
> You will end up triggering the warning for every ARCH != ARM...
>
Ok, I restricted the tagging to selected symbol, and we definitively
have this pattern occurring. It shall be fixed when/if we ends up
having a global configuration namespace.

I think I can work a patch.

 - Arnaud