[GR-60710] Use short for DynamicHub open-world type information.

Author: peter-hofer

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/hub/DynamicHub.java

@@ -40,11 +40,11 @@
 import static com.oracle.svm.core.code.RuntimeMetadataDecoderImpl.ALL_RECORD_COMPONENTS_FLAG;
 import static com.oracle.svm.core.code.RuntimeMetadataDecoderImpl.ALL_SIGNERS_FLAG;
 import static com.oracle.svm.core.code.RuntimeMetadataDecoderImpl.CLASS_ACCESS_FLAGS_MASK;
-import static com.oracle.svm.core.graal.meta.DynamicHubOffsets.writeObject;
-import static com.oracle.svm.core.graal.meta.DynamicHubOffsets.writeInt;
+import static com.oracle.svm.core.graal.meta.DynamicHubOffsets.writeByte;
 import static com.oracle.svm.core.graal.meta.DynamicHubOffsets.writeChar;
+import static com.oracle.svm.core.graal.meta.DynamicHubOffsets.writeInt;
+import static com.oracle.svm.core.graal.meta.DynamicHubOffsets.writeObject;
 import static com.oracle.svm.core.graal.meta.DynamicHubOffsets.writeShort;
-import static com.oracle.svm.core.graal.meta.DynamicHubOffsets.writeByte;
 import static com.oracle.svm.core.reflect.RuntimeMetadataDecoder.NO_DATA;
 
 import java.io.InputStream;
@@ -239,17 +239,20 @@ public final class DynamicHub implements AnnotatedElement, java.lang.reflect.Typ
     // region open-world only fields
 
     /**
-     * This stores the depth of the type in the inheritance hierarchy. If the type is an interface
-     * then the typeIDDepth is -1.
+     * This stores the depth of the type in the inheritance hierarchy. If the type is an interface,
+     * then the value is negative.
+     *
+     * Could be adapted so that {@link #getNumClassTypes()} can compute its value from this field,
+     * at the cost of increased size of type checks in code.
      */
     @UnknownPrimitiveField(availability = AfterHostedUniverse.class)//
-    private int typeIDDepth;
+    private short typeIDDepth;
 
     @UnknownPrimitiveField(availability = AfterHostedUniverse.class)//
-    private int numClassTypes;
+    private short numClassTypes;
 
     @UnknownPrimitiveField(availability = AfterHostedUniverse.class)//
-    private int numInterfaceTypes;
+    private short numInterfaceTypes;
 
     /**
      * Array containing this type's type check id information. During a type check, these slots are
@@ -517,9 +520,9 @@ public static DynamicHub allocate(String name, DynamicHub superHub, DynamicHub c
 
         // GR-59687: Determine typecheck related infos
         int typeID = 0;
-        int typeIDDepth = 0;
-        int numClassTypes = 2;
-        int numInterfacesTypes = 0;
+        short typeIDDepth = 0;
+        short numClassTypes = 2;
+        short numInterfacesTypes = 0;
         int[] openTypeWorldTypeCheckSlots = new int[numClassTypes + (numInterfacesTypes * 2)];
 
         byte additionalFlags = NumUtil.safeToUByte(makeFlag(IS_INSTANTIATED_BIT, true));
@@ -559,10 +562,10 @@ public static DynamicHub allocate(String name, DynamicHub superHub, DynamicHub c
         writeInt(hub, dynamicHubOffsets.getTypeIDOffset(), typeID);
         // skip typeCheckStart, typeCheckRange, typeCheckSlot and
         // closedTypeWorldTypeCheckSlots (closed-world only)
-        writeInt(hub, dynamicHubOffsets.getTypeIDDepthOffset(), typeIDDepth);
-        writeInt(hub, dynamicHubOffsets.getNumClassTypesOffset(), numClassTypes);
+        writeShort(hub, dynamicHubOffsets.getTypeIDDepthOffset(), typeIDDepth);
+        writeShort(hub, dynamicHubOffsets.getNumClassTypesOffset(), numClassTypes);
 
-        writeInt(hub, dynamicHubOffsets.getNumInterfaceTypesOffset(), numInterfacesTypes);
+        writeShort(hub, dynamicHubOffsets.getNumInterfaceTypesOffset(), numInterfacesTypes);
         writeObject(hub, dynamicHubOffsets.getOpenTypeWorldTypeCheckSlotsOffset(), openTypeWorldTypeCheckSlots);
 
         writeChar(hub, dynamicHubOffsets.getMonitorOffsetOffset(), monitorOffset);
@@ -677,9 +680,9 @@ public void setOpenTypeWorldData(CFunctionPointer[] vtable, int typeID,
         assert this.vtable == null : "Initialization must be called only once";
 
         this.typeID = typeID;
-        this.typeIDDepth = typeCheckDepth;
-        this.numClassTypes = numClassTypes;
-        this.numInterfaceTypes = numInterfaceTypes;
+        this.typeIDDepth = NumUtil.safeToShortAE(typeCheckDepth);
+        this.numClassTypes = NumUtil.safeToShortAE(numClassTypes);
+        this.numInterfaceTypes = NumUtil.safeToShortAE(numInterfaceTypes);
         this.openTypeWorldTypeCheckSlots = typeCheckSlots;
         this.vtable = vtable;
     }