RFR: 8308151: [JVMCI] capture JVMCI exceptions in hs-err

[Doug Simon]

On Tue, 16 May 2023 08:02:11 GMT, Doug Simon <dnsimon at openjdk.org> wrote:

> When there is a pending exception after a JVMCI upcall into libjvmci, the VM calls the ExceptionDescribe JNI function to print the exception. Unfortunately, this output goes to "a system error-reporting channel" [1] which may not be tty. It also means the output is not in a hs-err log should the VM then exit with a fatal error. This has historically made it harder to triage libgraal bugs (i.e. the console output is usually required in addition to the hs-err crash log).
> 
> This PR addresses these shortcomings by printing the exception info to a string which is added to the JVMCI event log (for hs-err):
> 
> JVMCI Events (11 events):
> ...
> Event: 0.274 Thread 0x0000000146819210 compiler.jvmci.TestUncaughtErrorInCompileMethod$CompilerCreationError
> Event: 0.274 Thread 0x0000000146819210  at compiler.jvmci.TestUncaughtErrorInCompileMethod$1.createCompiler(TestUncaughtErrorInCompileMethod.java:147)
> Event: 0.274 Thread 0x0000000146819210  at jdk.internal.vm.ci/jdk.vm.ci.hotspot.HotSpotJVMCIRuntime.getCompiler(HotSpotJVMCIRuntime.java:829)
> Event: 0.274 Thread 0x0000000146819210  at jdk.internal.vm.ci/jdk.vm.ci.hotspot.HotSpotJVMCIRuntime.compileMethod(HotSpotJVMCIRuntime.java:943)
> 
> 
> It is also be used to enhance the `-XX:+PrintCompilation` message issued for a failed compilation:
> 
> COMPILE SKIPPED: uncaught exception in call_HotSpotJVMCIRuntime_compileMethod [compiler.jvmci.TestUncaughtErrorInCompileMethod$CompilerCreationError]
> 
> 
> [1] https://docs.oracle.com/en/java/javase/17/docs/specs/jni/functions.html#exceptiondescribe

src/hotspot/share/jvmci/jvmciRuntime.cpp line 2047:

> 2045:                                                                      (jlong) compile_state, compile_state->task()->compile_id());
> 2046: #ifdef ASSERT
> 2047:   if (JVMCIENV->has_pending_exception() && JVMCICompileMethodExceptionIsFatal) {

It's a shame to introduce a VM flag (i.e., `JVMCICompileMethodExceptionIsFatal`) for a test case but I don't know of any other way to do this. As far as I know, system properties cannot be accessed here. Maybe using an environment variable is better than a VM flag?

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PR Review Comment: https://git.openjdk.org/jdk/pull/14000#discussion_r1194855033