src/java.base/share/classes/java/lang/classfile/attribute/StackMapFrameInfo.java

@@ -1,7 +1,7 @@
  /*
-  * Copyright (c) 2023, 2025, Oracle and/or its affiliates. All rights reserved.
+  * Copyright (c) 2023, 2026, 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
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this

@@ -28,16 +28,18 @@
  import java.lang.classfile.ClassFile;
  import java.lang.classfile.Label;
  import java.lang.classfile.Opcode;
  import java.lang.classfile.constantpool.ClassEntry;
  import java.lang.classfile.instruction.BranchInstruction;
+ import java.lang.classfile.constantpool.NameAndTypeEntry;
  import java.lang.constant.ClassDesc;
  import java.util.List;
  
  import jdk.internal.classfile.impl.StackMapDecoder;
  import jdk.internal.classfile.impl.StackMapGenerator;
  import jdk.internal.classfile.impl.TemporaryConstantPool;
+ import jdk.internal.javac.PreviewFeature;
  
  /**
   * Models a stack map frame in a {@link StackMapTableAttribute StackMapTable}
   * attribute (JVMS {@jvms 4.7.4}).  A stack map frame must appear at the
   * beginning of each basic block in a method (JVMS {@jvms 4.10.1}).

@@ -76,10 +78,19 @@
      /**
       * {@return the expanded operand stack types}
       */
      List<VerificationTypeInfo> stack();
  
+     /**
+      * {@return the expanded unset fields}
+      *
+      * @jvms strict-fields-4.7.4 The {@code StackMapTable} Attribute
+      * @since Valhalla
+      */
+     @PreviewFeature(feature = PreviewFeature.Feature.STRICT_FIELDS, reflective = true)
+     List<NameAndTypeEntry> unsetFields();
+ 
      /**
       * {@return a new stack map frame}
       *
       * @param target the location of the frame
       * @param locals the complete list of frame locals

@@ -88,11 +99,34 @@
       *         or {@code stack} exceeds the limit of {@link java.lang.classfile##u2 u2}
       */
      public static StackMapFrameInfo of(Label target,
              List<VerificationTypeInfo> locals,
              List<VerificationTypeInfo> stack) {
-         return new StackMapDecoder.StackMapFrameImpl(255, target, locals, stack);
+ 
+         return of(target, locals, stack, List.of());
+     }
+ 
+     /**
+      * {@return a new stack map frame}
+      * @param target the location of the frame
+      * @param locals the complete list of frame locals
+      * @param stack the complete frame stack
+      * @param unsetFields the complete list of unset fields
+      * @throws IllegalArgumentException if the number of elements in {@code locals},
+      *         {@code stack}, or {@code unsetFields} exceeds the limit of
+      *         {@link java.lang.classfile##u2 u2}; or if unset fields has
+      *         elements, but no {@link SimpleVerificationTypeInfo#UNINITIALIZED_THIS
+      *         uninitializedThis} is present in {@code locals}
+      * @since Valhalla
+      */
+     @PreviewFeature(feature = PreviewFeature.Feature.STRICT_FIELDS, reflective = true)
+     public static StackMapFrameInfo of(Label target,
+                                        List<VerificationTypeInfo> locals,
+                                        List<VerificationTypeInfo> stack,
+                                        List<NameAndTypeEntry> unsetFields) {
+ 
+         return new StackMapDecoder.StackMapFrameImpl(255, target, locals, stack, unsetFields);
      }
  
      /**
       * The type of a stack or local variable value.
       *