8015693: reduce NodeLiteralNode to NullLiteralNode

Reviewed-by: jlaskey, lagergren

nashorn/src/jdk/nashorn/internal/ir/LiteralNode.java

@@ -28,7 +28,6 @@ package jdk.nashorn.internal.ir;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
-
 import jdk.nashorn.internal.codegen.CompileUnit;
 import jdk.nashorn.internal.codegen.types.Type;
 import jdk.nashorn.internal.ir.annotations.Immutable;
@@ -242,8 +241,8 @@ public abstract class LiteralNode<T> extends Node implements PropertyKey {
      *
      * @return the new literal node
      */
-    public static LiteralNode<Node> newInstance(final long token, final int finish) {
-        return new NodeLiteralNode(token, finish);
+    public static LiteralNode<Object> newInstance(final long token, final int finish) {
+        return new NullLiteralNode(token, finish);
     }
 
     /**
@@ -253,8 +252,8 @@ public abstract class LiteralNode<T> extends Node implements PropertyKey {
      *
      * @return the new literal node
      */
-    public static LiteralNode<?> newInstance(final Node parent) {
-        return new NodeLiteralNode(parent.getToken(), parent.getFinish());
+    public static LiteralNode<Object> newInstance(final Node parent) {
+        return new NullLiteralNode(parent.getToken(), parent.getFinish());
     }
 
     @Immutable
@@ -496,33 +495,15 @@ public abstract class LiteralNode<T> extends Node implements PropertyKey {
         return new LexerTokenLiteralNode(parent.getToken(), parent.getFinish(), value);
     }
 
-    private static final class NodeLiteralNode extends LiteralNode<Node> {
-
-        private NodeLiteralNode(final long token, final int finish) {
-            this(token, finish, null);
-        }
-
-        private NodeLiteralNode(final long token, final int finish, final Node value) {
-            super(Token.recast(token, TokenType.OBJECT), finish, value);
-        }
-
-        private NodeLiteralNode(final LiteralNode<Node> literalNode) {
-            super(literalNode);
-        }
+    private static final class NullLiteralNode extends LiteralNode<Object> {
 
-        private NodeLiteralNode(final LiteralNode<Node> literalNode, final Node value) {
-            super(literalNode, value);
+        private NullLiteralNode(final long token, final int finish) {
+            super(Token.recast(token, TokenType.OBJECT), finish, null);
         }
 
         @Override
         public Node accept(final NodeVisitor<? extends LexicalContext> visitor) {
             if (visitor.enterLiteralNode(this)) {
-                if (value != null) {
-                    final Node newValue = value.accept(visitor);
-                    if(value != newValue) {
-                        return visitor.leaveLiteralNode(new NodeLiteralNode(this, newValue));
-                    }
-                }
                 return visitor.leaveLiteralNode(this);
             }
 
@@ -531,38 +512,13 @@ public abstract class LiteralNode<T> extends Node implements PropertyKey {
 
         @Override
         public Type getType() {
-            return value == null ? Type.OBJECT : super.getType();
+            return Type.OBJECT;
         }
 
         @Override
         public Type getWidestOperationType() {
-            return value == null ? Type.OBJECT : value.getWidestOperationType();
+            return Type.OBJECT;
         }
-
-    }
-    /**
-     * Create a new node literal for an arbitrary node
-     *
-     * @param token   token
-     * @param finish  finish
-     * @param value   the literal value node
-     *
-     * @return the new literal node
-     */
-    public static LiteralNode<Node> newInstance(final long token, final int finish, final Node value) {
-        return new NodeLiteralNode(token, finish, value);
-    }
-
-    /**
-     * Create a new node literal based on a parent node (source, token, finish)
-     *
-     * @param parent parent node
-     * @param value  node value
-     *
-     * @return the new literal node
-     */
-    public static LiteralNode<?> newInstance(final Node parent, final Node value) {
-        return new NodeLiteralNode(parent.getToken(), parent.getFinish(), value);
     }
 
     /**