src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/linker/JavaAdapterServices.java

*** 37,46 ****
--- 37,47 ----
  import java.lang.invoke.ConstantCallSite;
  import java.lang.invoke.MethodHandle;
  import java.lang.invoke.MethodHandles;
  import java.lang.invoke.MethodHandles.Lookup;
  import java.lang.invoke.MethodType;
+ import java.lang.reflect.Field;
  import java.security.AccessController;
  import java.security.CodeSigner;
  import java.security.CodeSource;
  import java.security.Permissions;
  import java.security.PrivilegedAction;
*** 49,58 ****
--- 50,60 ----
  import java.util.Objects;
  import jdk.internal.org.objectweb.asm.ClassWriter;
  import jdk.internal.org.objectweb.asm.Opcodes;
  import jdk.internal.org.objectweb.asm.Type;
  import jdk.internal.org.objectweb.asm.commons.InstructionAdapter;
+ import jdk.nashorn.api.scripting.ScriptObjectMirror;
  import jdk.nashorn.internal.objects.Global;
  import jdk.nashorn.internal.runtime.Context;
  import jdk.nashorn.internal.runtime.ECMAException;
  import jdk.nashorn.internal.runtime.JSType;
  import jdk.nashorn.internal.runtime.ScriptFunction;
*** 174,183 ****
--- 176,202 ----
          // fixed "toString" argument.
          return sobj.getMap().findProperty("toString") != null;
      }
  
      /**
+      * Returns the ScriptObject or Global field value from a ScriptObjectMirror using reflection.
+      *
+      * @param mirror the mirror object
+      * @param getGlobal true if we want the global object, false to return the script object
+      * @return the script object or global object
+      */
+     public static ScriptObject unwrapMirror(final Object mirror, final boolean getGlobal) {
+         assert mirror instanceof ScriptObjectMirror;
+         try {
+             final Field field = getGlobal ? MirrorFieldHolder.GLOBAL_FIELD : MirrorFieldHolder.SOBJ_FIELD;
+             return (ScriptObject) field.get(mirror);
+         } catch (final IllegalAccessException x) {
+             throw new RuntimeException(x);
+         }
+     }
+ 
+     /**
       * Delegate to {@link Bootstrap#bootstrap(Lookup, String, MethodType, int)}.
       * @param lookup MethodHandle lookup.
       * @param opDesc Dynalink dynamic operation descriptor.
       * @param type   Method type.
       * @param flags  flags for call type, trace/profile etc.
*** 289,294 ****
--- 308,333 ----
          return new ConstantCallSite(
                  MethodHandles.identity(Object[].class)
                  .asCollector(Object[].class, type.parameterCount())
                  .asType(type));
      }
+ 
+     // Initialization on demand holder for accessible ScriptObjectMirror fields
+     private static class MirrorFieldHolder {
+ 
+         private static final Field SOBJ_FIELD   = getMirrorField("sobj");
+         private static final Field GLOBAL_FIELD = getMirrorField("global");
+ 
+         private static Field getMirrorField(final String fieldName) {
+             try {
+                 final Field field = ScriptObjectMirror.class.getDeclaredField(fieldName);
+                 AccessController.doPrivileged((PrivilegedAction<Void>) () -> {
+                     field.setAccessible(true);
+                     return null;
+                 });
+                 return field;
+             } catch (final NoSuchFieldException e) {
+                 throw new RuntimeException(e);
+             }
+         }
+     }
  }