RFR (XS): 8062950: Bug in locking code when UseOptoBiasInlining is disabled: assert(dmw->is_neutral()) failed: invariant

[Christian Thalinger]

I’m not exactly sure who is our biased locking expert these days but I guess it’s someone from the runtime team.  CC’ing them.

> On Nov 5, 2014, at 7:38 AM, Doerr, Martin <martin.doerr at sap.com> wrote:
> 
> Hi,
>  
> we found a bug in MacroAssembler::fast_lock on x86 which shows up when UseOptoBiasInlining is switched off.
> The problem is that biased_locking_enter is used with swap_reg_contains_mark==true, which is no longer correct after biased_locking_enter was put in front of check for IsInflated.
>  
> Please review
> http://cr.openjdk.java.net/~goetz/webrevs/8062950-lockBug/webrev.00/ <http://cr.openjdk.java.net/~goetz/webrevs/8062950-lockBug/webrev.00/>
>  
> Best regards,
> Martin