Remove dummy slot from encoding layout.

Author: aardvark179

src/main/java/org/truffleruby/core/encoding/EncodingLayout.java

@@ -23,8 +23,7 @@ DynamicObjectFactory createEncodingShape(DynamicObject logicalClass,
 
     DynamicObject createEncoding(DynamicObjectFactory factory,
                                  Encoding encoding,
-                                 DynamicObject name,
-                                 boolean dummy);
+                                 DynamicObject name);
 
     boolean isEncoding(DynamicObject object);
     boolean isEncoding(Object object);
@@ -33,6 +32,4 @@ DynamicObject createEncoding(DynamicObjectFactory factory,
 
     DynamicObject getName(DynamicObject object);
 
-    boolean getDummy(DynamicObject object);
-
 }

src/main/java/org/truffleruby/core/encoding/EncodingManager.java

@@ -170,15 +170,15 @@ private void initializeLocaleEncoding(TruffleNFIPlatform nfi, NativeConfiguratio
     }
 
     @TruffleBoundary
-    private static DynamicObject newRubyEncoding(RubyContext context, Encoding encoding, byte[] name, int p, int end, boolean dummy) {
+    private static DynamicObject newRubyEncoding(RubyContext context, Encoding encoding, byte[] name, int p, int end) {
         assert p == 0 : "Ropes can't be created with non-zero offset: " + p;
         assert end == name.length : "Ropes must have the same exact length as the name array (len = " + end + "; name.length = " + name.length + ")";
 
         final Rope rope = RopeOperations.create(name, USASCIIEncoding.INSTANCE, CodeRange.CR_7BIT);
         final Rope cachedRope = context.getRopeCache().getRope(rope.getBytes(), rope.getEncoding(), rope.getCodeRange());
         final DynamicObject string = StringOperations.createFrozenString(context, cachedRope);
 
-        return Layouts.ENCODING.createEncoding(context.getCoreLibrary().getEncodingFactory(), encoding, string, dummy);
+        return Layouts.ENCODING.createEncoding(context.getCoreLibrary().getEncodingFactory(), encoding, string);
     }
 
     public static Encoding getEncoding(String name) {
@@ -240,7 +240,7 @@ public DynamicObject getRubyEncoding(Encoding encoding) {
     public synchronized DynamicObject defineEncoding(EncodingDB.Entry encodingEntry, byte[] name, int p, int end) {
         final Encoding encoding = encodingEntry.getEncoding();
         final int encodingIndex = encoding.getIndex();
-        final DynamicObject rubyEncoding = newRubyEncoding(context, encoding, name, p, end, encodingEntry.isDummy());
+        final DynamicObject rubyEncoding = newRubyEncoding(context, encoding, name, p, end);
 
         assert encodingIndex >= ENCODING_LIST_BY_ENCODING_INDEX.size() || ENCODING_LIST_BY_ENCODING_INDEX.get(encodingIndex) == null;
 

src/main/java/org/truffleruby/core/encoding/EncodingNodes.java

@@ -421,7 +421,7 @@ protected int getCacheLimit() {
         protected static boolean isDummy(DynamicObject encoding) {
             assert RubyGuards.isRubyEncoding(encoding);
 
-            return Layouts.ENCODING.getDummy(encoding);
+            return Layouts.ENCODING.getEncoding(encoding).isDummy();
         }
     }