Initial support for sealed classes

PiperOrigin-RevId: 400303125

java/com/google/turbine/binder/CanonicalTypeBinder.java

@@ -67,6 +67,7 @@ static SourceTypeBoundClass bind(
     ImmutableList<FieldInfo> fields = fields(base.source(), env, sym, base.fields());
     return new SourceTypeBoundClass(
         interfaceTypes.build(),
+        base.permits(),
         superClassType,
         typParamTypes,
         base.access(),

java/com/google/turbine/binder/CompUnitPreprocessor.java

@@ -225,6 +225,7 @@ private static TyDecl packageInfoTree(PkgDecl pkgDecl) {
         ImmutableList.of(),
         ImmutableList.of(),
         ImmutableList.of(),
+        ImmutableList.of(),
         TurbineTyKind.INTERFACE,
         /* javadoc= */ null);
   }

java/com/google/turbine/binder/ConstBinder.java

@@ -110,6 +110,7 @@ public SourceTypeBoundClass bind() {
     ImmutableList<MethodInfo> methods = bindMethods(base.methods());
     return new SourceTypeBoundClass(
         bindTypes(base.interfaceTypes()),
+        base.permits(),
         base.superClassType() != null ? bindType(base.superClassType()) : null,
         bindTypeParameters(base.typeParameterTypes()),
         base.access(),

java/com/google/turbine/binder/DisambiguateTypeAnnotations.java

@@ -71,6 +71,7 @@ public static SourceTypeBoundClass bind(
       SourceTypeBoundClass base, Env<ClassSymbol, TypeBoundClass> env) {
     return new SourceTypeBoundClass(
         base.interfaceTypes(),
+        base.permits(),
         base.superClassType(),
         base.typeParameterTypes(),
         base.access(),

java/com/google/turbine/binder/TypeBinder.java

@@ -229,6 +229,15 @@ private SourceTypeBoundClass bind() {
       interfaceTypes.add(bindClassTy(bindingScope, i));
     }
 
+    ImmutableList.Builder<ClassSymbol> permits = ImmutableList.builder();
+    for (Tree.ClassTy i : base.decl().permits()) {
+      Type type = bindClassTy(bindingScope, i);
+      if (!type.tyKind().equals(Type.TyKind.CLASS_TY)) {
+        throw new AssertionError(type.tyKind());
+      }
+      permits.add(((Type.ClassTy) type).sym());
+    }
+
     CompoundScope scope =
         base.scope()
             .toScope(Resolve.resolveFunction(env, owner))
@@ -251,6 +260,7 @@ private SourceTypeBoundClass bind() {
 
     return new SourceTypeBoundClass(
         interfaceTypes.build(),
+        permits.build(),
         superClassType,
         typeParameterTypes,
         base.access(),

java/com/google/turbine/binder/bound/SourceTypeBoundClass.java

@@ -44,6 +44,7 @@ public class SourceTypeBoundClass implements TypeBoundClass {
   private final ImmutableMap<TyVarSymbol, TyVarInfo> typeParameterTypes;
   private final @Nullable Type superClassType;
   private final ImmutableList<Type> interfaceTypes;
+  private final ImmutableList<ClassSymbol> permits;
   private final ImmutableList<RecordComponentInfo> components;
   private final ImmutableList<MethodInfo> methods;
   private final ImmutableList<FieldInfo> fields;
@@ -57,6 +58,7 @@ public class SourceTypeBoundClass implements TypeBoundClass {
 
   public SourceTypeBoundClass(
       ImmutableList<Type> interfaceTypes,
+      ImmutableList<ClassSymbol> permits,
       @Nullable Type superClassType,
       ImmutableMap<TyVarSymbol, TyVarInfo> typeParameterTypes,
       int access,
@@ -75,6 +77,7 @@ public SourceTypeBoundClass(
       SourceFile source,
       Tree.TyDecl decl) {
     this.interfaceTypes = interfaceTypes;
+    this.permits = permits;
     this.superClassType = superClassType;
     this.typeParameterTypes = typeParameterTypes;
     this.access = access;
@@ -116,6 +119,11 @@ public ImmutableList<ClassSymbol> interfaces() {
     return result.build();
   }
 
+  @Override
+  public ImmutableList<ClassSymbol> permits() {
+    return permits;
+  }
+
   @Override
   public int access() {
     return access;

java/com/google/turbine/binder/bound/TypeBoundClass.java

@@ -18,6 +18,7 @@
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
+import com.google.turbine.binder.sym.ClassSymbol;
 import com.google.turbine.binder.sym.FieldSymbol;
 import com.google.turbine.binder.sym.MethodSymbol;
 import com.google.turbine.binder.sym.ParamSymbol;
@@ -43,6 +44,9 @@ public interface TypeBoundClass extends HeaderBoundClass {
   /** Implemented interface types. */
   ImmutableList<Type> interfaceTypes();
 
+  /** The permitted direct subclasses. */
+  ImmutableList<ClassSymbol> permits();
+
   ImmutableMap<TyVarSymbol, TyVarInfo> typeParameterTypes();
 
   /** Declared fields. */

java/com/google/turbine/binder/bytecode/BytecodeBoundClass.java

@@ -306,6 +306,11 @@ public ImmutableList<Type> interfaceTypes() {
     return interfaceTypes.get();
   }
 
+  @Override
+  public ImmutableList<ClassSymbol> permits() {
+    return ImmutableList.of();
+  }
+
   private final Supplier<ImmutableMap<TyVarSymbol, TyVarInfo>> typeParameterTypes =
       Suppliers.memoize(
           new Supplier<ImmutableMap<TyVarSymbol, TyVarInfo>>() {

java/com/google/turbine/bytecode/Attribute.java

@@ -45,7 +45,8 @@ enum Kind {
     NEST_HOST("NestHost"),
     NEST_MEMBERS("NestMembers"),
     RECORD("Record"),
-    TURBINE_TRANSITIVE_JAR("TurbineTransitiveJar");
+    TURBINE_TRANSITIVE_JAR("TurbineTransitiveJar"),
+    PERMITTED_SUBCLASSES("PermittedSubclasses");
 
     private final String signature;
 
@@ -396,6 +397,20 @@ List<Attribute> attributes() {
     }
   }
 
+  /** A JVMS §4.7.31 PermittedSubclasses attribute. */
+  class PermittedSubclasses implements Attribute {
+    final List<String> permits;
+
+    public PermittedSubclasses(List<String> permits) {
+      this.permits = permits;
+    }
+
+    @Override
+    public Kind kind() {
+      return Kind.PERMITTED_SUBCLASSES;
+    }
+  }
+
   /** A custom attribute for recording the original jar of repackaged transitive classes. */
   class TurbineTransitiveJar implements Attribute {
 

java/com/google/turbine/bytecode/AttributeWriter.java

@@ -95,6 +95,9 @@ public void write(ByteArrayDataOutput output, Attribute attribute) {
       case RECORD:
         writeRecord(output, (Attribute.Record) attribute);
         break;
+      case PERMITTED_SUBCLASSES:
+        writePermittedSubclasses(output, (Attribute.PermittedSubclasses) attribute);
+        break;
       case TURBINE_TRANSITIVE_JAR:
         writeTurbineTransitiveJar(output, (Attribute.TurbineTransitiveJar) attribute);
         break;
@@ -318,6 +321,16 @@ private void writeRecord(ByteArrayDataOutput output, Attribute.Record attribute)
     output.write(data);
   }
 
+  private void writePermittedSubclasses(
+      ByteArrayDataOutput output, Attribute.PermittedSubclasses attribute) {
+    output.writeShort(pool.utf8(attribute.kind().signature()));
+    output.writeInt(2 + attribute.permits.size() * 2);
+    output.writeShort(attribute.permits.size());
+    for (String permits : attribute.permits) {
+      output.writeShort(pool.classInfo(permits));
+    }
+  }
+
   private void writeTurbineTransitiveJar(
       ByteArrayDataOutput output, TurbineTransitiveJar attribute) {
     output.writeShort(pool.utf8(attribute.kind().signature()));

java/com/google/turbine/bytecode/ClassFile.java

@@ -37,6 +37,7 @@ public class ClassFile {
   private final @Nullable String signature;
   private final @Nullable String superClass;
   private final List<String> interfaces;
+  private final List<String> permits;
   private final List<MethodInfo> methods;
   private final List<FieldInfo> fields;
   private final List<AnnotationInfo> annotations;
@@ -55,6 +56,7 @@ public ClassFile(
       @Nullable String signature,
       @Nullable String superClass,
       List<String> interfaces,
+      List<String> permits,
       List<MethodInfo> methods,
       List<FieldInfo> fields,
       List<AnnotationInfo> annotations,
@@ -71,6 +73,7 @@ public ClassFile(
     this.signature = signature;
     this.superClass = superClass;
     this.interfaces = interfaces;
+    this.permits = permits;
     this.methods = methods;
     this.fields = fields;
     this.annotations = annotations;
@@ -113,6 +116,11 @@ public List<String> interfaces() {
     return interfaces;
   }
 
+  /** The permitted direct subclasses. */
+  public List<String> permits() {
+    return permits;
+  }
+
   /** Methods declared by this class or interfaces type. */
   public List<MethodInfo> methods() {
     return methods;

java/com/google/turbine/bytecode/ClassReader.java

@@ -143,6 +143,7 @@ private ClassFile read() {
         signature,
         superClass,
         interfaces,
+        /* permits= */ ImmutableList.of(),
         methodinfos,
         fieldinfos,
         annotations.build(),

java/com/google/turbine/bytecode/LowerAttributes.java

@@ -54,6 +54,9 @@ static List<Attribute> classAttributes(ClassFile classfile) {
     if (classfile.record() != null) {
       attributes.add(recordAttribute(classfile.record()));
     }
+    if (!classfile.permits().isEmpty()) {
+      attributes.add(new Attribute.PermittedSubclasses(classfile.permits()));
+    }
     if (classfile.transitiveJar() != null) {
       attributes.add(new Attribute.TurbineTransitiveJar(classfile.transitiveJar()));
     }

java/com/google/turbine/deps/Transitive.java

@@ -95,6 +95,7 @@ public static ClassFile trimClass(ClassFile cf, @Nullable String jarFile) {
         cf.signature(),
         cf.superName(),
         cf.interfaces(),
+        cf.permits(),
         // drop methods, except for annotations where we need to resolve key/value information
         (cf.access() & TurbineFlag.ACC_ANNOTATION) == TurbineFlag.ACC_ANNOTATION
             ? cf.methods()

java/com/google/turbine/lower/Lower.java

@@ -192,6 +192,7 @@ private byte[] lower(SourceModuleInfo module, Set<ClassSymbol> symbols, int majo
             /* signature= */ null,
             /* superClass= */ null,
             /* interfaces= */ ImmutableList.of(),
+            /* permits= */ ImmutableList.of(),
             /* methods= */ ImmutableList.of(),
             /* fields= */ ImmutableList.of(),
             annotations,
@@ -259,6 +260,10 @@ private byte[] lower(
     for (ClassSymbol i : info.interfaces()) {
       interfaces.add(sig.descriptor(i));
     }
+    List<String> permits = new ArrayList<>();
+    for (ClassSymbol i : info.permits()) {
+      permits.add(sig.descriptor(i));
+    }
 
     ClassFile.RecordInfo record = null;
     if (info.kind().equals(TurbineTyKind.RECORD)) {
@@ -310,6 +315,7 @@ record = new ClassFile.RecordInfo(components.build());
             signature,
             superName,
             interfaces,
+            permits,
             methods,
             fields.build(),
             annotations,

java/com/google/turbine/model/TurbineFlag.java

@@ -55,5 +55,8 @@ public final class TurbineFlag {
   /** Synthetic constructors (e.g. of inner classes and enums). */
   public static final int ACC_SYNTH_CTOR = 1 << 18;
 
+  public static final int ACC_SEALED = 1 << 19;
+  public static final int ACC_NON_SEALED = 1 << 20;
+
   private TurbineFlag() {}
 }