JDK-8300566 : [Lilliput/JDK17] Properly set ZF on anon-check path
  • Type: Bug
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: repo-lilliput
  • Priority: P2
  • Status: Resolved
  • Resolution: Fixed
  • OS: generic
  • CPU: aarch64
  • Submitted: 2023-01-18
  • Updated: 2023-01-23
  • Resolved: 2023-01-23
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Other
repo-lilliputFixed
Related Reports
Relates :  
JDK-8300440 - [Lilliput] Implement alternative fast-locking scheme
Description
In AArch64's fast_unlock(), we need to check if the monitor owner is ANONYMOUS (only with Lilliput/fast-locking), and if so, call the runtime to fix this before exiting the monitor. I tried to be smart and used tbnz there, but it turns out that tbnz does *not* set the zero flag, but we do need the ZF set correctly on exit of fast_unlock, so that C2 generated code would actually call the slow path. Therefore we need to use the longer tst/br instructions instead.
Comments
A pull request was submitted for review. URL: https://git.openjdk.org/lilliput-jdk17u/pull/4 Date: 2023-01-18 16:07:01 +0000
18-01-2023