Re: Linux 6.3-rc3

Kalle Valo
2023-03-22T12:45:00Z

Nathan Chancellor <nathan@kernel.org> writes:

> On Mon, Mar 20, 2023 at 11:26:17AM -0700, Linus Torvalds wrote:
>> On Mon, Mar 20, 2023 at 11:05 AM Nathan Chancellor <nathan@kernel.org> wrote:
>> >
>> > On the clang front, I am still seeing the following warning turned error
>> > for arm64 allmodconfig at least:
>> >
>> > drivers/gpu/host1x/dev.c:520:6: error: variable 'syncpt_irq' is uninitialized when used here [-Werror,-Wuninitialized]
>> > if (syncpt_irq < 0)
>> > ^~~~~~~~~~
>>
>> Hmm. I do my arm64 allmodconfig builds with gcc, and I'm surprised
>> that gcc doesn't warn about this.
>
> Perhaps these would make doing allmodconfig builds with clang more
> frequently less painful for you?
>
> https://lore.kernel.org/llvm/20230319235619.GA18547@dev-arch.thelio-3990X/

Thank you, at least for me this is really helpful. I tried now clang for
the first time but seeing a strange problem.

I prefer to define the compiler in GNUmakefile so it's easy to change
compilers and I don't need to remember the exact command line. So I have
this in the top level GNUmakefile (all the rest commented out):

LLVM=/opt/clang/llvm-16.0.0/bin/

If I run 'make oldconfig' it seems to use clang but after I run just
'make' it seems to switch back to the host GCC compiler and ask for GCC
specific config questions again. Workaround for this seems to be adding
'export LLVM' to GNUmakefile, after that also 'make' uses clang as
expected.

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