The generated JfrNativeSettings union holds an array of settings ("bits") overlayed with named structures ("ev"). The latter only exists for debugging:

```
union JfrNativeSettings {
  // Array version.
  jfrNativeEventSetting bits[NUMBER_OF_EVENTS];
  // Then, to make it easy to debug,
  // add named struct members also.
  struct {
    jfrNativeEventSetting pad[NUMBER_OF_RESERVED_EVENTS];
    jfrNativeEventSetting Duration;
    jfrNativeEventSetting Instant;
    jfrNativeEventSetting Value;
    jfrNativeEventSetting Text;
    jfrNativeEventSetting ZThreadDebug;
    ...
    jfrNativeEventSetting DeprecatedInvocation;
    jfrNativeEventSetting StackFrame;
  } ev;
};

```

I noticed that sizes of `bits` vs `ev` did not match up (even adding the fix Matthias proposed for JDK-8332699). Looks like the `ev` substructure contains members that are not events:

```
jfrNativeEventSetting VirtualSpace;
jfrNativeEventSetting ObjectSpace;
...
jfrNativeEventSetting MetaspaceSizes;
...
jfrNativeEventSetting CopyFailed;
...
jfrNativeEventSetting G1EvacuationStatistics;
...
jfrNativeEventSetting CalleeMethod;
...
jfrNativeEventSetting StackFrame;
```

These are types of fields, not events. Therefore, the overlayed named structures would not match up against their corresponding bits[event id] slot.

The ev substructure is not used during building, so I assume one only notices during debugging.

(error relates to, but is different from, the issue described in JDK-8332699)