8295851: Do not use ttyLock in BytecodeTracer::trace #25915
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Webrevs
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dholmes-ora
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Jun 23, 2025
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| // We need a global instance to keep track of the method being printed so we can report that | ||
| // the method has changed. If this method is redefined and removed, that's ok because the method passed in won't match, and | ||
| // this will print that one. | ||
| static Method* _current_method = nullptr; |
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And if we are calling trace_interpreter from multiple threads they will each stomp on this shared global field. Sorry I can't see how some form of locking is not needed here.
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This didn't need ttyLock for synchronization, the code only needs to see if the method changes so it can print the method name before the bytecodes, like:
[490166] static void java.lang.String.()
[490166] 13 18 putstatic 613 <java/lang/String.CASE_INSENSITIVE_ORDER:Ljava/util/Comparator;>
[490166] 14 21 return
[490166] static void java.lang.System.()
[490166] 15 0 invokestatic 471 <java/lang/System.registerNatives()V>
[490166] 16 3 aconst_null
[490166] 17 4 putstatic 474 <java/lang/System.in:Ljava/io/InputStream;>
Verified manually and added some parallelism to the test, and fixed trace() to initialize is_linked(), which it always is.
Also ran tier1-4.
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