JDK-8218885 : Restore pop_frame and force_early_return functionality for Graal
  • Type: Bug
  • Component: hotspot
  • Sub-Component: jvmti
  • Affected Version: 12
  • Priority: P5
  • Status: Open
  • Resolution: Unresolved
  • OS: generic
  • CPU: generic
  • Submitted: 2019-02-13
  • Updated: 2021-09-24
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Description
pop_frame and force_early_return caps were disabled if JVMCI compiler is used (by JDK-8218025)
Need to re-enable them after fixing corresponding bugs.
Comments
There is a comment in JDK-8218403: Dean Long added a comment - 2019-02-04 18:56 Here's a patch to popframe009 to demonstrate the problem with C1/C2 and -Xcomp: http://cr.openjdk.java.net/~dlong/popframe009/webrev/
20-09-2021

[~never] I'm trying to refresh my memory. My last comment in 8195635 says the "The problem with -Xcomp (JDK-8218403) still exists. The original problem with adjust_comp_level() is gone now". Then rereading 8218403, the only example it gives is adjustCompilationLevel(), so perhaps there is still a theoretical problem but no practical way to reproduce it anymore. So I'd say it's probably safe to undo this change now. I vaguely remember that wait_for_jvmci_completion() might have been involved in some scenarios (one way JVMCI is still different from other compilers), but I can't remember the details and that code has changed.
20-09-2021

This has just popped up for us an issue as people are using graal on JDK 17. I believe the original problem was caused by Graal's use of the adjustCompilationLevel callback which has since been removed by JDK-8219403. We'd like to undo this change since we should be have the same as C1/C2 in this regard now. Is there any way to test or confirm this now that Graal has been removed? I guess if I could mach5 test a pre graal removal and post adjustCompilationLevel removal version hotspot that would confirm it. I'm not really sure that it's really necessary anymore since we're not really different than the other compilers now. cc [~dlong]
18-09-2021