8330464: hserr generic events - add entry for the before_exit calls

Reviewed-by: rrich, lucy

src/hotspot/share/runtime/java.cpp

@@ -78,6 +78,7 @@
 #include "runtime/vm_version.hpp"
 #include "sanitizers/leak.hpp"
 #include "utilities/dtrace.hpp"
+#include "utilities/events.hpp"
 #include "utilities/globalDefinitions.hpp"
 #include "utilities/macros.hpp"
 #include "utilities/vmError.hpp"
@@ -366,6 +367,8 @@ void before_exit(JavaThread* thread, bool halt) {
   #define BEFORE_EXIT_DONE    2
   static jint volatile _before_exit_status = BEFORE_EXIT_NOT_RUN;
 
+  Events::log(thread, "Before exit entered");
+
   // Note: don't use a Mutex to guard the entire before_exit(), as
   // JVMTI post_thread_end_event and post_vm_death_event will run native code.
   // A CAS or OSMutex would work just fine but then we need to manipulate

src/hotspot/share/runtime/threads.cpp

@@ -833,10 +833,10 @@ jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
 
 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
 // the program falls off the end of main(). Another VM exit path is through
-// vm_exit() when the program calls System.exit() to return a value or when
-// there is a serious error in VM. The two shutdown paths are not exactly
-// the same, but they share Shutdown.shutdown() at Java level and before_exit()
-// and VM_Exit op at VM level.
+// vm_exit(), when the program calls System.exit() to return a value, or when
+// there is a serious error in VM.
+// These two separate shutdown paths are not exactly the same, but they share
+// Shutdown.shutdown() at Java level and before_exit() and VM_Exit op at VM level.
 //
 // Shutdown sequence:
 //   + Shutdown native memory tracking if it is on