On Fri, Aug 26, 2011 at 10:17 AM, Sriraman Tallam <tmsri...@google.com> wrote:
> On Fri, Aug 26, 2011 at 10:10 AM, H.J. Lu <hjl.to...@gmail.com> wrote:
>> On Fri, Aug 26, 2011 at 10:06 AM, Sriraman Tallam <tmsri...@google.com>
>> wrote:
>>> On Thu, Aug 25, 2011 at 6:02 PM, H.J. Lu <hjl.to...@gmail.com> wrote:
>>>> On Thu, Aug 25, 2011 at 5:37 PM, Sriraman Tallam <tmsri...@google.com>
>>>> wrote:
>>>>> Hi,
>>>>>
>>>>> Thanks for all the comments. I am attaching a new patch
>>>>> incorporating all of the changes mentioned, mainly :
>>>>>
>>>>> 1) Make __cpu_indicator_init a constructor in libgcc and guard to call
>>>>> it only once.
>>>>
>>>> This is unreliable and you don't need 3 symbols from libgcc. You can use
>>>
>>> Do you mean it is unreliable because of the constructor ordering problem?
>>>
>>
>> You do not have total control when __cpu_indicator_init is called.
>
> Like discussed before, for non-ctor functions, which in my opinion is
> the common use case, it works out great because __cpu_indicator_init
> is guaranteed to be called and I save doing an extra check. It is only
>> for other ctors where this is a problem. So other ctors call this
> explicitly. What did I miss?
>
I have
static void foo ( void ) __attribute__((constructor));
static void foo ( void )
{
...
call bar ();
...
}
in my application. bar () uses those cpu specific functions.
foo () is called before __cpu_indicator_init. Since IFUNC
returns the cpu specific function address only for the
first call, the proper cpu specific functions will never be used.
--
H.J.
