[GR-38163] Implement getParentFrameDescriptor()

Author: eregon

src/main/java/org/truffleruby/language/RubyRootNode.java

@@ -21,6 +21,7 @@
 import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.source.SourceSection;
 import org.truffleruby.language.methods.Split;
+import org.truffleruby.parser.ParentFrameDescriptor;
 
 public class RubyRootNode extends RubyBaseRootNode {
 
@@ -65,6 +66,16 @@ public Object execute(VirtualFrame frame) {
         return body.execute(frame);
     }
 
+    @Override
+    public FrameDescriptor getParentFrameDescriptor() {
+        var info = getFrameDescriptor().getInfo();
+        if (info instanceof ParentFrameDescriptor) {
+            return ((ParentFrameDescriptor) info).getDescriptor();
+        } else {
+            return null;
+        }
+    }
+
     @Override
     public boolean isCloningAllowed() {
         return split != Split.NEVER;