Re: [PATCH v5] selftest: size: Add size test for Linux kernel

On Wed, Dec 3, 2014 at 5:29 PM, Tim Bird <[email protected]> wrote:
>>> diff --git a/tools/testing/selftests/size/Makefile b/tools/testing/selftests/size/Makefile
>>> new file mode 100644
>>> index 0000000..47f8e9c
>>> --- /dev/null
>>> +++ b/tools/testing/selftests/size/Makefile
>>> @@ -0,0 +1,15 @@
>>> +#ifndef CC
>>> +    CC = $(CROSS_COMPILE)gcc
>>> +#endif
>>
>> I think the following is preferable:
>>
>>   CC := $(CROSS_COMPILE)$(CC)
>>
>>
>> It allows optionally setting a custom CC, as well as optionally CROSS_COMPILE.
>
> I'm not sure I follow this.
>
> If CC is unset, you get only the CROSS_COMPILE prefix.
> If CC is set to e.g. 'gcc', then you get a nicely formatted toolchain string.
> But if CC already has the prefix applied, then this will result in
>   having it duplicated, which surely won't work correctly.
>
> In the long run, I would hope that a higher level Makefile or environment setting
> will be setting the toolchain string appropriately (as well as handling build flags)
> which is why I wanted to use an ifndef (which Thomas correctly pointed out is just
> wrong).
>
> Actually, after getting this tiny program accepted, my next task was working on a
> proper fix for handling cross compilation in a more generic (not case-by-case) way.
>
> CROSS_COMPILE prefix usage looks a bit uncoordinated in the tools directory, but most
> tests seem to be favoring $(CROSS_COMPILE)gcc.
>
>  $ cd tools ; mgrep CROSS

[...]

> I agree it's desirable not to hardcode gcc, but we seem to be doing it all over
> the place already.

Seems like it's time to start integrating the tests with the regular Kbuild
system, which handles cross-compilation fine...

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds