RFR: 8344165: Trace exceptions with a complete call-stack [v9]

[Coleen Phillimore]

On Fri, 20 Jun 2025 17:13:08 GMT, Ioi Lam <iklam at openjdk.org> wrote:

>> This PR makes it easier to analyze exceptions without modifying the JVM or the app to print call stacks:
>> 
>> Excerpt from the test case ExceptionsTest.java. 
>> 
>> 
>> [0.042s][info][exceptions] Exception <a 'java/lang/RuntimeException'{0x0000000474019530}: Test exception 1 for logging>
>> [                        ]  thrown in interpreter method <{method} {0x000079e52c4005b0} 'bar' '()V' in 'ExceptionsTest$InternalClass'>
>> [                        ]  at bci 9 for thread 0x000079e58c02c7b0 (main)
>> [0.042s][info][exceptions,stacktrace] Exception <a 'java/lang/RuntimeException'{0x0000000474019530}: Test exception 1 for logging>
>> [0.042s][info][exceptions,stacktrace] 	at ExceptionsTest$InternalClass.bar(ExceptionsTest.java:110)
>> [0.042s][info][exceptions,stacktrace] 	at ExceptionsTest$InternalClass.foo(ExceptionsTest.java:105)
>> [0.042s][info][exceptions,stacktrace] 	at ExceptionsTest$InternalClass.main(ExceptionsTest.java:100)
>> [0.042s][info][exceptions           ] Found matching handler for exception of type "java.lang.RuntimeException" in method "bar" at BCI: 10
>> Exception 1 caught.
>> 
>> 
>> - Note that the old `[exceptions]` log  is triggered by `InterpreterRuntime::exception_handler_for_exception()` and prints one level of the stack while the interpreter is looking for a handler. However, once a handler is found (inside `bar()`), the `[exceptions]` log terminates, and we do not know about the `foo()` or `main()` methods.
>> 
>> - The `[exceptions,stacktrace]` log is printed only when an exception is thrown:
>>     - By an `_athrow` bytecode. See comments around `Exceptions::log_exception_stacktrace(Handle exception, methodHandle method, int bci)`
>>     - By native code in Exceptions::special_exception() and  and Exceptions::_throw()).
>> 
>> **Concurrent Exceptions**
>> 
>> Neither the old  `[exceptions]` or the new `[exceptions,stacktrace]` logs distinguish between multiple exceptions that are thrown and handled concurrently. The users should use something like `-Xlog:exceptions,exceptions+stack::tags,tid` to include the thread ID into the log output, and use an external tool (such as a script) to demultiplex the logs.
>
> Ioi Lam has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - refactor
>  - Reimplement -- print stack trace only when it is a known throwing site

src/hotspot/share/utilities/exceptions.cpp line 635:

> 633: // and Exceptions::_throw()).
> 634: void Exceptions::log_exception_stacktrace(Handle exception, methodHandle method, int bci) {
> 635:   if (method->is_native() || (Bytecodes::Code) *method->bcp_from(bci) == Bytecodes::_athrow) {

Do you mean !method->is_native() && athrow?  How do you get here from a native method ?

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PR Review Comment: https://git.openjdk.org/jdk/pull/25522#discussion_r2159485434