Re: Clang powerpc pthread_arch.h patch.

[Richard Pennington <rich@pennware.com>]

On 12/02/2013 01:48 AM, Rich Felker wrote:
> On Sun, Nov 24, 2013 at 04:46:48PM -0600, Richard Pennington wrote:
>> On 11/24/2013 04:31 PM, Rich Felker wrote:
>>> On Sun, Nov 24, 2013 at 01:23:44PM -0600, Richard Pennington wrote:
>>>> I had a problem with clang and __pthread_self() on the powerpc. This
>>>> is the patch I applied to work around it.
>>>>
>>>> Index: pthread_arch.h
>>>> ===================================================================
>>>> --- pthread_arch.h      (revision 3604)
>>>> +++ pthread_arch.h      (working copy)
>>>> @@ -1,6 +1,11 @@
>>>>   static inline struct pthread *__pthread_self()
>>>>   {
>>>> +#ifdef __clang__
>>>> +        char *tp;
>>>> +        __asm__ __volatile__ ("mr %0, 2" : "=r" (tp) : : "2" );
>>>> +#else
>>> Why is "2" in the clobberlist? It's just read, not written. In
>>> principle there should be some way to indicate that the asm has hidden
>>> state it reads so that it couldn't be reordered before the initial asm
>>> call that initializes the register, but that would be massive
>>> reordering that's not likely to happen anyway. I'm not sure what the
>>> right way to encode this as a constraint is...
>>>
>>> Rich
>> Hi Rich,
>>
>> You're right about the clobber list. Not that it matters much in
>> this case I think.
> Committed a fix based on your patch; let me know if you still have
> problems with it.
>
> Rich
>
>
Thanks Rich. It has been working fine here.

-Rich