8199149: Improve the exception message thrown by VarHandle of unsupported operation

Reviewed-by: liach, jvernee

src/java.base/share/classes/java/lang/invoke/IndirectVarHandle.java

@@ -103,6 +103,6 @@ import java.util.function.BiFunction;
     @Override
     MethodHandle getMethodHandleUncached(int mode) {
         MethodHandle targetHandle = target.getMethodHandle(mode); // might throw UOE of access mode is not supported, which is ok
-        return handleFactory.apply(AccessMode.values()[mode], targetHandle);
+        return handleFactory.apply(AccessMode.valueFromOrdinal(mode), targetHandle);
     }
 }

src/java.base/share/classes/java/lang/invoke/VarForm.java

@@ -26,6 +26,7 @@ package java.lang.invoke;
 
 import jdk.internal.vm.annotation.DontInline;
 import jdk.internal.vm.annotation.ForceInline;
+import jdk.internal.vm.annotation.Hidden;
 import jdk.internal.vm.annotation.Stable;
 
 import java.lang.invoke.VarHandle.AccessMode;
@@ -108,6 +109,7 @@ final class VarForm {
     }
 
     @ForceInline
+    @Hidden
     final MemberName getMemberName(int mode) {
         // Can be simplified by calling getMemberNameOrNull, but written in this
         // form to improve interpreter/coldpath performance.
@@ -115,7 +117,7 @@ final class VarForm {
         if (mn == null) {
             mn = resolveMemberName(mode);
             if (mn == null) {
-                throw new UnsupportedOperationException();
+                throw new UnsupportedOperationException(AccessMode.valueFromOrdinal(mode).methodName());
             }
         }
         return mn;
@@ -132,7 +134,7 @@ final class VarForm {
 
     @DontInline
     MemberName resolveMemberName(int mode) {
-        AccessMode value = AccessMode.values()[mode];
+        AccessMode value = AccessMode.valueFromOrdinal(mode);
         String methodName = value.methodName();
         MethodType type = methodType_table[value.at.ordinal()].insertParameterTypes(0, VarHandle.class);
         return memberName_table[mode] = MethodHandles.Lookup.IMPL_LOOKUP

src/java.base/share/classes/java/lang/invoke/VarHandle.java

@@ -2003,6 +2003,11 @@ public abstract sealed class VarHandle implements Constable
                 default -> throw new IllegalArgumentException("No AccessMode value for method name " + methodName);
             };
         }
+
+        private static final @Stable AccessMode[] VALUES = values();
+        static AccessMode valueFromOrdinal(int mode) {
+            return VALUES[mode];
+        }
     }
 
     static final class AccessDescriptor {
@@ -2215,7 +2220,7 @@ public abstract sealed class VarHandle implements Constable
      * @throws UnsupportedOperationException if the access mode is not supported
      */
     MethodHandle getMethodHandleUncached(int mode) {
-        MethodType mt = accessModeType(AccessMode.values()[mode]).
+        MethodType mt = accessModeType(AccessMode.valueFromOrdinal(mode)).
                 insertParameterTypes(0, VarHandle.class);
         MemberName mn = vform.getMemberName(mode);
         DirectMethodHandle dmh = DirectMethodHandle.make(mn);

src/java.base/share/classes/java/lang/invoke/VarHandleGuards.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2023, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it