RFR(XS): JDK-8030808 dtrace/hotspot/Monitors/Monitors001 fails in product builds on solaris-sparc

[Frederic Parain]

Hi David,

The dtrace_waited_probe() function successfully
work around the tail-call optimization for some
time, and still works for non SPARC platforms.
This is why I didn't try to remove it.
Now, something new is breaking this code again
on SPARC, and this changetset just aims to fix
the code on SPARC without impacting other
platform.

Of course, The "Good" solution is to clearly
identify the issue in the SS12u1 compiler and
to fix it.

Fred

On 02/06/2014 06:07 AM, David Holmes wrote:
> Hi Fred,
>
> On 6/02/2014 12:23 AM, Frederic Parain wrote:
>> Greetings,
>>
>> Please review this small fix for bug 8030808.
>> The bug is caused by a compiler bug preventing the
>> hotspot:::monitor-waited DTrace probe to be fired
>> on SPARC. After several failed attempts to fix
>> the compiler behavior with #pragma and flags, I'm
>> proposing this simple workaround.
>>
>> CR:
>> https://bugs.openjdk.java.net/browse/JDK-8030808
>> Webrev:
>> http://cr.openjdk.java.net/~fparain/8030808/webrev.00/
>
> So ... if the dtrace_waited_probe call was attempting (but failing?) to
> work around the tail-call optimization bug, would it not suffice to drop
> the call and just add a return:
>
> DTRACE_MONITOR_PROBE(waited, monitor, obj(), THREAD);
> // This dummy return is in place to get around dtrace bug 6254741.  Once
> // that's fixed we can remove it and change this back to a void method
> return 0;
>
> ??
>
> David
> -----
>
>> The fix has been tested with the dtrace/hotspot test suite
>> and the vm.quick testlist.
>>
>> Thanks,
>>
>> Fred
>>

-- 
Frederic Parain - Oracle
Grenoble Engineering Center - France
Phone: +33 4 76 18 81 17
Email: Frederic.Parain at oracle.com