JDK-8369166 : [lworld] Avoid final field barriers at the end of constructors for strict fields
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: repo-valhalla
  • Priority: P3
  • Status: Open
  • Resolution: Unresolved
  • Submitted: 2025-10-06
  • Updated: 2025-10-06
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repo-valhallaUnresolved
Related Reports
Relates :  
JDK-8367785 - [lworld] Compiler adherence to new memory model rules for strict instance fields
Description
JDK-8367785 added a barrier to the beginning of java.lang.Object::<init> for strict fields. Now if the field is strict and *final*, we will also add barriers to the end of the constructors:
https://github.com/openjdk/valhalla/blob/274d56076260a490ed52df29373216617ddf73ef/src/hotspot/share/c1/c1_GraphBuilder.cpp#L1645-L1652

https://github.com/openjdk/valhalla/blob/274d56076260a490ed52df29373216617ddf73ef/src/hotspot/share/opto/parse1.cpp#L1092-L1099

I think those barriers can be omitted because the object can only escape after j.l.Object::<init> for strict fields.