Re: Use (two) different compilers at build-time?

[Sedat Dilek]

On Mon, Sep 7, 2015 at 10:15 PM, Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Mon, Sep 7, 2015 at 12:12 PM, Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote:
>>
>> is it possible to use a different compiler at build-time?
>>
>> I have here a problem with mm/percpu.c and wanted to build everything
>> with LLVM/Clang but this single file with GCC.
>>
>> Is that possible?
>
> It should work fine. It's occasionally how people bisect compiler bugs
> in the kernel (although then it's usually just two different versions
> of the same compiler), and I think people have done that with llvm
> too. After all, llvm object files link to gcc-produced object files in
> user space (ie libraries are most often compiled with different
> compilers).
>
> So no _guarantees_ (especially since the kernel sometimes does odd
> things), but there's no overwhelming reason it shouldn't work, and
> there are several reasons it should be fine.
>

OK.

So, how do I do that conveniently?

In case of percpu.o - hack in the mm/Makefile?

So, I have a percpu.o compiled with clang in my build-dir and want to
recompile just that single file with gcc and create a new bzImage.

Hope I could explain it more exactly.

- Sedat -
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/