Request for reviews (S): 7050280: assert(u->as_Unlock()->is_eliminated()) failed: sanity

[Tom Rodriguez]

Looks good.

tom

On Jun 2, 2011, at 7:25 PM, Vladimir Kozlov wrote:

> http://cr.openjdk.java.net/~kvn/7050280/webrev
> 
> Fixed 7050280: assert(u->as_Unlock()->is_eliminated()) failed: sanity
> 
> Marking locks for elimination is done in IGVN. Unfortunately the order of IGVN worklist processing may affect this marking. Also during EA obj may point to several objects but after few ideal graph transformations (CCP) it may point to only one non escaping object (but still using phi), corresponding locks and unlocks will be marked for elimination. Later obj could be replaced with a new node (new phi) and will be no escape information about it. And later after some graph reshape other locks and unlocks (which were not marked for elimination before) are connected to this new obj but they still will not be marked for elimination since new obj has no escape information.
> 
> Fix:
> Do first round of locks marking during EA after ConnectionGraph is constructed when all nodes have escape information. During Macro nodes expansion move creation of new eliminated BoxLock into new separate method which is called before locks elimination. Use this method to mark all associated (same box and obj) lock and unlock nodes which were not marked before (instead of the assert).
> 
> Tested with failing case and full CTW.