JDK-8307493 : Use thread register C2MacroAssembler::fast_lock()
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 21
  • Priority: P4
  • Status: Open
  • Resolution: Unresolved
  • OS: generic
  • CPU: x86
  • Submitted: 2023-05-04
  • Updated: 2023-05-05
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tbdUnresolved
Related Reports
Blocks :  
JDK-8291555 - Implement alternative fast-locking scheme
Description
In the 32-bit section of C2MacroAssembelr::fast_lock() we first CAS a stack-pointer and after this has been successful, fetch the current thread and store that into the stack-lock. With JDK-8291555 we can simply use the thread-register that's passed into fast_lock() and can avoid the intermediate store.
Also, fix the clearing of tmp register to use xorl, as the comment says.