Re: [PATCH] LLVMLinux: Remove warning about returning an uninitialized variable

[Behan Webster <behanw@converseincode.com>]

On 03/31/14 15:11, H. Peter Anvin wrote:
> On 03/31/2014 03:10 PM, Behan Webster wrote:
>>>> diff --git a/include/asm-generic/cmpxchg-local.h
>>>> b/include/asm-generic/cmpxchg-local.h
>>>> index d8d4c89..4c41bb8 100644
>>>> --- a/include/asm-generic/cmpxchg-local.h
>>>> +++ b/include/asm-generic/cmpxchg-local.h
>>>> @@ -41,6 +41,7 @@ static inline unsigned long
>>>> __cmpxchg_local_generic(volatile void *ptr,
>>>>            break;
>>>>        default:
>>>>            wrong_size_cmpxchg(ptr);
>>>> +        prev = 0;
>>>>        }
>>>>        raw_local_irq_restore(flags);
>>>>        return prev;
>>>>
>>> Shouldn't this be a build time assert (__compiletime_error())?
>> I changed it to a __noreturn on wrong_size_cmpxchg thanks to James
>> Bottomley.
>>
>> Which would be better?
>>
> __compiletime_error traps at compile time rather than link time, which
> is what you want.
The idea is to remove the compile time warning that the return code 
"prev" isn't initialized in the default case. Indicating that 
wrong_size_cmpxchg doesn't return fixes that false positive.

Behan

-- 
Behan Webster
behanw@converseincode.com