JDK-8369835 : [lworld] Intrinsify new instance-accepting array unsafe operations
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: repo-valhalla
  • Priority: P4
  • Status: Open
  • Resolution: Unresolved
  • Submitted: 2025-10-14
  • Updated: 2025-11-10
The Version table provides details related to the release that this issue/RFE will be addressed.

Unresolved : Release in which this issue/RFE will be addressed.
Resolved: Release in which this issue/RFE has been resolved.
Fixed : Release in which this issue/RFE has been fixed. The release containing this fix may be available for download as an Early Access Release or a General Availability Release.

To download the current JDK release, click here.
Other
repo-valhallaUnresolved
Related Reports
Blocks :  
JDK-8357245 - [lworld] Improve performance of Flat array var handles
Duplicate :  
JDK-8369866 - [lworld] Intrinsify new unsafe methods added by JDK-8369835
Relates :  
JDK-8366705 - [lworld] Re-work of arrays meta-data
Description
Since arrays are now polymorphic, it would be helpful if core libraries can access properties of arrays to classify them quickly. Here are some desired APIs in Unsafe:

1. arrayLayout0 - the actual type of array (combined with class)
2. arrayInstanceBaseOffset0 - the offset from the flat/refArrayKlass
3. arrayInstanceIndexScale0 - the scale from the flat/refArrayKlass

These were introduced by JDK-8368933 (and renamed by JDK-8368933).
Comments
Ah right, sorry I missed that. Converting back.
16-10-2025
Hi Tobias, the 3 unsafe methods I am describing already exist in lworld - they are the methods to be intrinsified.
15-10-2025
I'm converting this into two RFEs: (1) Implement the unsafe methods, (2) subtask to intrinsify them in the JITs
15-10-2025