12 RFR(XS) 8214329: SwingMark SubMenus 9% regression in 12-b19 on Linux client

[Sean Mullan]

Looks good, although I think someone from the HotSpot Group should also 
review it.

On the bug, can you add the details below into the Description? Also, 
since you have no regression test, you will need a noreg label (I guess 
noreg-perf would be appropriate). Also, the bug says it is BlockedBy 
JDK-8215205 which should probably be removed.

Thanks,
Sean

On 12/17/18 5:49 PM, dean.long at oracle.com wrote:
> https://bugs.openjdk.java.net/browse/JDK-8214329
> http://cr.openjdk.java.net/~dlong/8214329/webrev/
> 
> In "8212605: Pure-Java implementation of AccessController.doPrivileged", 
> the stackwalk in JVM_GetStackAccessControlContext was changed from using 
> a vframeStream to using a javaVFrame, so that it could access locals. 
> However this caused a regression because javaVFrame has more overhead. 
> JDK-8215205 fixes the problem by allowing the use of javaVFrame only 
> when needed.
> 
> This change reverts JVM_GetStackAccessControlContext back to using 
> vframeStream, and uses the new API in JDK-8215205 to get a javaVFrame 
> lazily.  It also removes two unnecessary calls to java_sender().
> 
> dl