[9] RFR (XS): 8153167: Allow stack walking pass through method handle intrinsic frames

[Zoltán Majó]

Hi,


please review the patch for 8153167.

https://bugs.openjdk.java.net/browse/JDK-8153167

Problem: Currently, stack walking is stopped when frame of a method 
handle intrinsic is encountered (i.e., a method handle intrinsic is not 
considered as a "safe" sender) [1]. (Tobias drew my attention to this 
issue.)

The restriction was added to the frame walking code by JDK-8068945 [2] 
and is actually not necessary: Since JDK-8068945 frames belonging to 
method handle intrinsics are also treated as usual compiled frames [3].


Solution: Remove the unnecessary condition.

Webrev:
http://cr.openjdk.java.net/~zmajo/8153167/webrev.00/

Testing:
- JPRT;
- several runs of jstack, pstack, jfr, and Sun Studio Performance 
Analyzer tracing a test generating long chains of method handle calls 
(with -Xcomp +/-PreserveFramePointer);
- RBT testing is in progress (-Xmixed/-Xcomp +-PreserveFramePointer) and 
has shown no failures so far.

Thank you!

Best regards,


Zoltan

[1]: 
http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/file/8911d94e888b/src/cpu/x86/vm/frame_x86.cpp#l227
[2]: http://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/382e9e4b3b71#l9.9
[3]: http://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/382e9e4b3b71#l9.41