[0.54] Detect any monitorenter before point of dynamic loop transfers - #22317
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vijaysun-omr merged 1 commit intoJul 28, 2025
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Dynamic loop transfer can transfer control from the interpreter into a JIT-compiled method after the point at which monitorenter bytecode instructions have been executed. With Java 24 and later, the JVM uses the JIT's live monitor metadata to locate monitors that might need to be detached from carrier threads when the owning virtual thread is unmounted. This is enabled if the J9_EXTENDED_RUNTIME3_YIELD_PINNED_CONTINUATION flag is set in extendedRuntimeFlags3, which can be turned off by specifying the option -XX:-YieldPinnedVirtualThreads. If the JIT is unable to determine that no monitorenters will be executed prior to the entry point for dynamic loop transfer, it must fail the compilation. This change follows predecessor paths in the CFG from the blocks identified as potential DLT entry points to see whether a monitorenter could have been encountered before the DLT occurred. If that might be possible, the compilation fails. Also, if the JVM requires correct live monitor maps, force the disableLiveMonitorMetadata JIT option off. Finally, the disableInlineMonEnt and disableInlineMonExit options can be set in a fashion that's specific to a particular method compilation. Whether they should be forced off needs to be considered earlier in J9::Options::feLatePostProcess. Signed-off-by: Henry Zongaro <zongaro@ca.ibm.com>
hzongaro
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vijaysun-omr
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0xdaryl
July 28, 2025 13:36
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@vijaysun-omr, may I ask you to merge this change to the 0.54.0-release branch? |
vijaysun-omr
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Jul 28, 2025
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Dynamic loop transfer can transfer control from the interpreter into a JIT-compiled method after the point at which
monitorenterbytecode instructions have been executed. With Java 24 and later, the JVM uses the JIT's live monitor metadata to locate monitors that might need to be detached from carrier threads when the owning virtual thread is unmounted.If the JIT is unable to determine that no
monitorenters will be executed prior to the entry point for dynamic loop transfer, it must fail the compilation.Fixes: #22266
Port of pull request #22291 to v0.54.0-release branch