Re: [PATCH] kbuild, LLVMLinux: only use warnings when using clang

[Michal Marek <mmarek@suse.cz>]

On 2014-07-01 12:12, Borislav Petkov wrote:
> On Mon, Jun 30, 2014 at 05:42:26PM -0700, behanw@converseincode.com wrote:
>> From: Behan Webster <behanw@converseincode.com>
>>
>> Only consider clang warnings in Kbuild when using the clang compiler.
>>
>> Signed-off-by: Behan Webster <behanw@converseincode.com>
>> ---
>>  scripts/Makefile.extrawarn | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
>> index 6564350..e350127 100644
>> --- a/scripts/Makefile.extrawarn
>> +++ b/scripts/Makefile.extrawarn
>> @@ -26,7 +26,7 @@ warning-1 += $(call cc-option, -Wmissing-include-dirs)
>>  warning-1 += $(call cc-option, -Wunused-but-set-variable)
>>  warning-1 += $(call cc-disable-warning, missing-field-initializers)
>>  
>> -# Clang
>> +ifeq ($(COMPILER),clang)
>>  warning-1 += $(call cc-disable-warning, initializer-overrides)
>>  warning-1 += $(call cc-disable-warning, unused-value)
>>  warning-1 += $(call cc-disable-warning, format)
>> @@ -35,6 +35,7 @@ warning-1 += $(call cc-disable-warning, sign-compare)
>>  warning-1 += $(call cc-disable-warning, format-zero-length)
>>  warning-1 += $(call cc-disable-warning, uninitialized)
>>  warning-1 += $(call cc-option, -fcatch-undefined-behavior)
>> +endif
> 
> Ok, just to make sure I understand that whole use case correctly:
> 
> The disabling of those warnings is really intended for the case where
> people build the kernel with "W=1" on the make cmdline *and* clang?

Behan, Jan-Simon,

can you explain why are those -Wno-... options needed in the W=1 case?
The whole point of the W= option is to enable noisy warnings, so I don't
quite get why you want to silence these.

Thanks,
Michal