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

@@ -23,10 +23,11 @@
   * questions.
   */
  
  package java.lang.invoke;
  
+ import jdk.internal.misc.PreviewFeatures;
  import jdk.internal.misc.CDS;
  import jdk.internal.util.ClassFileDumper;
  import sun.invoke.util.VerifyAccess;
  import sun.security.action.GetBooleanAction;
  

@@ -35,22 +36,30 @@
  import java.lang.classfile.ClassFile;
  import java.lang.classfile.CodeBuilder;
  import java.lang.classfile.MethodBuilder;
  import java.lang.classfile.Opcode;
  import java.lang.classfile.TypeKind;
+ 
  import java.lang.constant.ClassDesc;
+ import java.lang.constant.ConstantDescs;
  import java.lang.constant.MethodTypeDesc;
+ import java.lang.reflect.AccessFlag;
+ import java.lang.reflect.ClassFileFormatVersion;
  import java.lang.reflect.Modifier;
+ import java.util.ArrayList;
+ import java.util.HashSet;
  import java.util.LinkedHashSet;
  import java.util.List;
  import java.util.Set;
  import java.util.function.Consumer;
  
  import static java.lang.classfile.ClassFile.*;
  import java.lang.classfile.attribute.ExceptionsAttribute;
+ import java.lang.classfile.attribute.LoadableDescriptorsAttribute;
  import java.lang.classfile.constantpool.ClassEntry;
  import java.lang.classfile.constantpool.ConstantPoolBuilder;
+ import java.lang.classfile.constantpool.Utf8Entry;
  
  import static java.lang.constant.ConstantDescs.*;
  import static java.lang.invoke.MethodHandleNatives.Constants.NESTMATE_CLASS;
  import static java.lang.invoke.MethodHandleNatives.Constants.STRONG_LOADER_LINK;
  import static java.lang.invoke.MethodType.methodType;

@@ -309,12 +318,19 @@
          }
          final boolean finalAccidentallySerializable = accidentallySerializable;
          final byte[] classBytes = ClassFile.of().build(lambdaClassEntry, pool, new Consumer<ClassBuilder>() {
              @Override
              public void accept(ClassBuilder clb) {
-                 clb.withFlags(ACC_SUPER | ACC_FINAL | ACC_SYNTHETIC)
+                 clb.withVersion(ClassFileFormatVersion.latest().major(), (PreviewFeatures.isEnabled() ? 0xFFFF0000 : 0))
+                    .withFlags(ACC_SUPER | ACC_FINAL | ACC_SYNTHETIC)
                     .withInterfaceSymbols(interfaces);
+ 
+                 // generate LoadableDescriptors attribute if it references any value class
+                 if (PreviewFeatures.isEnabled()) {
+                     generateLoadableDescriptors(clb);
+                 }
+ 
                  // Generate final fields to be filled in by constructor
                  for (int i = 0; i < argDescs.length; i++) {
                      clb.withField(argName(i), argDescs[i], ACC_PRIVATE | ACC_FINAL);
                  }
  

@@ -543,10 +559,77 @@
              cob.loadLocal(TypeKind.from(argType), cob.parameterSlot(i));
              TypeConvertingMethodAdapter.convertType(cob, argType, implMethodType.parameterType(captureArity + i), dynamicMethodType.parameterType(i));
          }
      }
  
+     /*
+      * LoadableDescriptors attribute builder
+      */
+     static class LoadableDescriptorsAttributeBuilder {
+         private final Set<String> loadableDescriptors = new HashSet<>();
+         LoadableDescriptorsAttributeBuilder(Class<?> targetClass) {
+             if (requiresLoadableDescriptors(targetClass)) {
+                 loadableDescriptors.add(targetClass.descriptorString());
+             }
+         }
+ 
+         /*
+          * Add the value types referenced in the given MethodType.
+          */
+         LoadableDescriptorsAttributeBuilder add(MethodType mt) {
+             // parameter types
+             for (Class<?> paramType : mt.ptypes()) {
+                 if (requiresLoadableDescriptors(paramType)) {
+                     loadableDescriptors.add(paramType.descriptorString());
+                 }
+             }
+             // return type
+             if (requiresLoadableDescriptors(mt.returnType())) {
+                 loadableDescriptors.add(mt.returnType().descriptorString());
+             }
+             return this;
+         }
+ 
+         LoadableDescriptorsAttributeBuilder add(MethodType... mtypes) {
+             for (MethodType mt : mtypes) {
+                 add(mt);
+             }
+             return this;
+         }
+ 
+         boolean requiresLoadableDescriptors(Class<?> cls) {
+             return cls.isValue() && cls.accessFlags().contains(AccessFlag.FINAL);
+         }
+ 
+         boolean isEmpty() {
+             return loadableDescriptors.isEmpty();
+         }
+ 
+         void build(ClassBuilder clb) {
+             if (!isEmpty()) {
+                 List<Utf8Entry> lds = new ArrayList<Utf8Entry>(loadableDescriptors.size());
+                 for (String ld : loadableDescriptors) {
+                     lds.add(clb.constantPool().utf8Entry(ld));
+                 }
+                 clb.with(LoadableDescriptorsAttribute.of(lds));
+             }
+         }
+     }
+ 
+     /**
+      * Generate LoadableDescriptors attribute if it references any value class
+      */
+     private void generateLoadableDescriptors(ClassBuilder clb) {
+         LoadableDescriptorsAttributeBuilder builder = new LoadableDescriptorsAttributeBuilder(targetClass);
+         builder.add(factoryType)
+                .add(interfaceMethodType)
+                .add(implMethodType)
+                .add(dynamicMethodType)
+                .add(altMethods)
+           .build(clb);
+     }
+ 
      private Opcode invocationOpcode() throws InternalError {
          return switch (implKind) {
              case MethodHandleInfo.REF_invokeStatic     -> Opcode.INVOKESTATIC;
              case MethodHandleInfo.REF_newInvokeSpecial -> Opcode.INVOKESPECIAL;
              case MethodHandleInfo.REF_invokeVirtual    -> Opcode.INVOKEVIRTUAL;