work in progress on calling destroy of a class

Author: ktoso

.gitignore

@@ -16,6 +16,9 @@ BuildLogic/out/
 **/build/
 lib/
 
+# Ignore JVM crash logs
+**/*.log
+
 # Ignore package resolved
 Package.resolved
 

Samples/SwiftKitSampleApp/src/main/java/com/example/swift/HelloJava2Swift.java

@@ -18,6 +18,7 @@
 import com.example.swift.generated.MySwiftClass;
 
 // Import javakit/swiftkit support libraries
+import org.swift.swiftkit.SwiftArena;
 import org.swift.swiftkit.SwiftKit;
 import org.swift.swiftkit.SwiftValueWitnessTable;
 
@@ -45,23 +46,22 @@ static void examples() {
 //         obj.voidMethod();
 //         obj.takeIntMethod(42);
 
-//        try (var arena = SwiftArena.ofConfined()) {
-            var instance = new MySwiftClass(
-//                    arena,
-                    1111, 2222);
+        MySwiftClass unsafelyEscaped = null;
+        try (var arena = SwiftArena.ofConfined()) {
+            var instance = new MySwiftClass(arena, 1111, 2222);
+            unsafelyEscaped = instance;
+
+            var num = instance.makeIntMethod();
 
             System.out.println("MySwiftClass.TYPE_MANGLED_NAME = " + MySwiftClass.TYPE_MANGLED_NAME);
-            var swiftType = SwiftKit.getTypeByMangledNameInEnvironment(MySwiftClass.TYPE_MANGLED_NAME);
-            System.out.println("swiftType = " + swiftType);
-//           MemorySegment typeMetadata = SwiftValueWitnessTable.fullTypeMetadata(swiftType.$memorySegment());
-//           System.out.println("typeMetadata = " + typeMetadata);
-//
-//
-//            System.out.printf("size of type      = %d%n", SwiftValueWitnessTable.sizeOfSwiftType(swiftType.$memorySegment()));
-//            System.out.printf("stride of type    = %d%n", SwiftValueWitnessTable.strideOfSwiftType(swiftType.$memorySegment()));
-//            System.out.printf("alignment of type = %d%n", SwiftValueWitnessTable.alignmentOfSwiftType(swiftType.$memorySegment()));
-//            System.out.printf("layout of type    = %s%n", SwiftValueWitnessTable.layoutOfSwiftType(swiftType.$memorySegment()).toString());
+           MemorySegment typeMetadata = SwiftValueWitnessTable.fullTypeMetadata(MySwiftClass.TYPE_METADATA.$memorySegment());
+           System.out.println("typeMetadata = " + typeMetadata);
+
+           SwiftKit.release(instance);
+        } // instance should be deallocated
+
+        var num = unsafelyEscaped.makeIntMethod();
 
-//        } // instance should be deallocated
+        System.out.println("DONE.");
     }
 }

Sources/JExtractSwift/Swift2JavaTranslator+Printing.swift

@@ -113,20 +113,24 @@ extension Swift2JavaTranslator {
   public func printImportedClass(_ printer: inout CodePrinter, _ decl: ImportedNominalType) {
     printHeader(&printer)
     printPackage(&printer)
-    printImports(&printer)  // TODO print any imports the file may need, it we talk to other Swift modules
+    printImports(&printer)
 
     printClass(&printer, decl) { printer in
-      // Metadata
+      // Ensure we have loaded the library where the Swift type was declared before we attempt to resolve types in Swift
+      printStaticLibraryLoad(&printer)
+
+      // Prepare type metadata, we're going to need these when invoking e.g. initializers so cache them in a static
       printer.print(
         """
         public static final String TYPE_MANGLED_NAME = "\(decl.swiftMangledName ?? "")";
-        static final MemorySegment TYPE_METADATA = SwiftKit.getTypeByMangledNameInEnvironment(TYPE_MANGLED_NAME);
+        public static final SwiftAnyType TYPE_METADATA = SwiftKit.getTypeByMangledNameInEnvironment(TYPE_MANGLED_NAME).get();
+        public final SwiftAnyType $swiftType() {
+            return TYPE_METADATA;
+        }
         """
       )
       printer.print("")
 
-      printStaticLibraryLoad(&printer)
-
       // Initializers
       for initDecl in decl.initializers {
         printClassConstructors(&printer, initDecl)
@@ -141,6 +145,9 @@ extension Swift2JavaTranslator {
       for funcDecl in decl.methods {
         printFunctionDowncallMethods(&printer, funcDecl)
       }
+
+      // Helper methods and default implementations
+      printHeapObjectToStringMethod(&printer, decl)
     }
   }
 
@@ -345,7 +352,6 @@ extension Swift2JavaTranslator {
       public static final ValueLayout.OfLong SWIFT_UINT = SWIFT_INT64;
 
       public static final AddressLayout SWIFT_SELF = SWIFT_POINTER;
-      public static final AddressLayout SWIFT_TYPE_METADATA_PTR = SWIFT_POINTER;
       """
     )
   }
@@ -412,7 +418,7 @@ extension Swift2JavaTranslator {
       /**
        * Create an instance of {@code \(parentName.unqualifiedJavaTypeName)}.
        *
-       * \(decl.renderCommentSnippet ?? " *")
+       \(decl.renderCommentSnippet ?? " *")
        */
       public \(parentName.unqualifiedJavaTypeName)(\(renderJavaParamDecls(decl, selfVariant: .wrapper))) {
         this(/*arena=*/null, \(renderForwardParams(decl, selfVariant: .wrapper)));
@@ -426,7 +432,7 @@ extension Swift2JavaTranslator {
        * Create an instance of {@code \(parentName.unqualifiedJavaTypeName)}.
        * This instance is managed by the passed in {@link SwiftArena} and may not outlive the arena's lifetime.
        *
-       * \(decl.renderCommentSnippet ?? " *")
+       \(decl.renderCommentSnippet ?? " *")
        */
       public \(parentName.unqualifiedJavaTypeName)(SwiftArena arena, \(renderJavaParamDecls(decl, selfVariant: .wrapper))) {
         var mh$ = \(descClassIdentifier).HANDLE;
@@ -435,7 +441,7 @@ extension Swift2JavaTranslator {
               traceDowncall(\(renderForwardParams(decl, selfVariant: nil)));
             }
 
-            this.selfMemorySegment = (MemorySegment) mh$.invokeExact(\(renderForwardParams(decl, selfVariant: nil)), TYPE_METADATA);
+            this.selfMemorySegment = (MemorySegment) mh$.invokeExact(\(renderForwardParams(decl, selfVariant: nil)), TYPE_METADATA.$memorySegment());
             if (arena != null) {
                 arena.register(this);
             }
@@ -824,7 +830,7 @@ extension Swift2JavaTranslator {
   public func printHeapObjectToStringMethod(_ printer: inout CodePrinter, _ decl: ImportedNominalType) {
     printer.print(
       """
-      @Override 
+      @Override
       public String toString() {
           return getClass().getSimpleName() + "(" +
                   SwiftKit.nameOfSwiftType($swiftType().$memorySegment(), true) +

SwiftKit/src/main/java/org/swift/swiftkit/SwiftAnyType.java

@@ -24,7 +24,7 @@ public final class SwiftAnyType implements SwiftMemoryResource {
             SwiftValueLayout.SWIFT_POINTER
     );
 
-    final MemorySegment memorySegment;
+    private final MemorySegment memorySegment;
 
     public SwiftAnyType(MemorySegment memorySegment) {
         if (memorySegment.byteSize() == 0) {
@@ -40,11 +40,11 @@ public SwiftAnyType(SwiftHeapObject object) {
         }
 
         String mangledName = object.$layout().name().get();
-        var tySegment = SwiftKit.getTypeByMangledNameInEnvironment(mangledName);
-//        if (tySegment.isEmpty()) {
-//            throw new IllegalArgumentException("A Swift Any.Type cannot be null!");
-//        }
-        this.memorySegment = tySegment; //.get().memorySegment;
+        var type = SwiftKit.getTypeByMangledNameInEnvironment(mangledName);
+        if (type.isEmpty()) {
+            throw new IllegalArgumentException("A Swift Any.Type cannot be null!");
+        }
+        this.memorySegment = type.get().memorySegment;
     }
 
 
@@ -68,7 +68,7 @@ public boolean immortal() {
     public String toString() {
         return "AnySwiftType{" +
                 "name=" + SwiftKit.nameOfSwiftType(memorySegment, true) +
-                "memorySegment=" + memorySegment +
+                ", memorySegment=" + memorySegment +
                 '}';
     }
 }

SwiftKit/src/main/java/org/swift/swiftkit/SwiftArena.java

@@ -47,7 +47,7 @@ static SwiftArena ofConfined() {
 
 final class ConfinedSwiftMemorySession implements SwiftArena {
 
-    final Arena underlying;
+//    final Arena underlying;
     final Thread owner;
     final SwiftResourceList resources;
 
@@ -58,19 +58,21 @@ final class ConfinedSwiftMemorySession implements SwiftArena {
 
     public ConfinedSwiftMemorySession(Thread owner) {
         this.owner = owner;
-        underlying = Arena.ofConfined();
+//        underlying = Arena.ofConfined();
         resources = new ConfinedResourceList();
         state = new AtomicInteger(ACTIVE);
     }
 
     @Override
     public MemorySegment allocate(long byteSize, long byteAlignment) {
-        return underlying.allocate(byteSize, byteAlignment);
+//        return underlying.allocate(byteSize, byteAlignment);
+        return null;
     }
 
     @Override
     public MemorySegment.Scope scope() {
-        return underlying.scope();
+        return null;
+//        return underlying.scope();
     }
 
     public void checkValid() throws RuntimeException {
@@ -83,13 +85,13 @@ public void checkValid() throws RuntimeException {
 
     @Override
     public void register(SwiftHeapObject object) {
-        SwiftKit.log.info("Registered " + object.$memorySegment() + " in " + this);
-        this.resources.add(new SwiftHeapObjectCleanup(object.$memorySegment()));
+        System.out.println("Registered " + object.$memorySegment() + " in " + this);
+        this.resources.add(new SwiftHeapObjectCleanup(object));
     }
 
     @Override
     public void register(SwiftValue value) {
-        this.resources.add(new SwiftHeapObjectCleanup(value.$memorySegment()));
+        this.resources.add(new SwiftValueCleanup(value.$memorySegment()));
     }
 
     @Override
@@ -104,10 +106,10 @@ public void close() {
 
 
         // Those the underlying arena
-        this.underlying.close();
+//        this.underlying.close();
 
         // After this method returns normally, the scope must be not alive anymore
-        assert (!this.scope().isAlive());
+//        assert (!this.scope().isAlive());
     }
 
     /**
@@ -142,7 +144,7 @@ public void cleanup() {
 }
 
 final class UnexpectedRetainCountException extends RuntimeException {
-    public UnexpectedRetainCountException(MemorySegment resource, long retainCount, int expectedRetainCount) {
+    public UnexpectedRetainCountException(Object resource, long retainCount, int expectedRetainCount) {
         super(("Attempting to cleanup managed memory segment %s, but it's retain count was different than [%d] (was %d)! " +
                 "This would result in destroying a swift object that is still retained by other code somewhere."
         ).formatted(resource, expectedRetainCount, retainCount));

SwiftKit/src/main/java/org/swift/swiftkit/SwiftHeapObject.java

@@ -20,4 +20,5 @@
  * Represents a wrapper around a Swift heap object, e.g. a {@code class} or an {@code actor}.
  */
 public interface SwiftHeapObject extends SwiftMemoryResource {
+    SwiftAnyType $swiftType();
 }

SwiftKit/src/main/java/org/swift/swiftkit/SwiftKit.java

@@ -19,6 +19,7 @@
 import java.lang.foreign.*;
 import java.lang.invoke.MethodHandle;
 import java.util.Arrays;
+import java.util.Optional;
 import java.util.logging.Logger;
 import java.util.stream.Collectors;
 
@@ -33,8 +34,6 @@ public class SwiftKit {
     private static final Arena LIBRARY_ARENA = Arena.ofAuto();
     static final boolean TRACE_DOWNCALLS = Boolean.getBoolean("jextract.trace.downcalls");
 
-    static final Logger log = Logger.getLogger("SwiftKit");
-
     static {
         System.loadLibrary(STDLIB_DYLIB_NAME);
         System.loadLibrary("SwiftKitSwift");
@@ -272,8 +271,8 @@ private static class getTypeByStringByteArray {
      * @param mangledName The mangled type name (often prefixed with {@code $s}).
      * @return the Swift Type wrapper object
      */
-    public static MemorySegment getTypeByMangledNameInEnvironment(String mangledName) {
-        log.info("Get Any.Type for mangled name: " + mangledName);
+    public static Optional<SwiftAnyType> getTypeByMangledNameInEnvironment(String mangledName) {
+        System.out.println("Get Any.Type for mangled name: " + mangledName);
 
         var mh$ = swift_getTypeByMangledNameInEnvironment.HANDLE;
         try {
@@ -289,19 +288,14 @@ public static MemorySegment getTypeByMangledNameInEnvironment(String mangledName
             try (Arena arena = Arena.ofConfined()) {
                 MemorySegment stringMemorySegment = arena.allocateFrom(mangledName);
 
-                var ty = (MemorySegment) mh$.invokeExact(stringMemorySegment, mangledName.length(), MemorySegment.NULL, MemorySegment.NULL);
+                var memorySegment = (MemorySegment) mh$.invokeExact(stringMemorySegment, mangledName.length(), MemorySegment.NULL, MemorySegment.NULL);
 
-                return ty;
-
-//                if (ty.address() == 0) {
-//                    return Optional.empty();
-//                }
-//
-//                var wrapper = new SwiftAnyType(ty);
-//                log.info("Resolved type '"+mangledName+"' as: " + wrapper);
-//
-//                return Optional.of(wrapper);
+                if (memorySegment.address() == 0) {
+                    return Optional.empty();
+                }
 
+                var wrapper = new SwiftAnyType(memorySegment);
+                return Optional.of(wrapper);
             }
         } catch (Throwable ex$) {
             throw new AssertionError("should not reach here", ex$);
@@ -313,7 +307,7 @@ public static MemorySegment getTypeByMangledNameInEnvironment(String mangledName
      * <p>
      * This function copes with the fact that a Swift.Int might be 32 or 64 bits.
      */
-    public static final long getSwiftInt(MemorySegment memorySegment, long offset) {
+    public static long getSwiftInt(MemorySegment memorySegment, long offset) {
         if (SwiftValueLayout.SWIFT_INT == ValueLayout.JAVA_LONG) {
             return memorySegment.get(ValueLayout.JAVA_LONG, offset);
         } else {
@@ -358,14 +352,18 @@ private static class swift_getTypeName {
      *                     e.g. the result of a {@link swift_getTypeByMangledNameInEnvironment} call
      */
     public static String nameOfSwiftType(MemorySegment typeMetadata, boolean qualified) {
-        try {
-            try (Arena arena = Arena.ofConfined()) {
-                MemorySegment charsAndLength = (MemorySegment) swift_getTypeName.HANDLE.invokeExact((SegmentAllocator) arena, typeMetadata, qualified);
-                MemorySegment utf8Chars = charsAndLength.get(SwiftValueLayout.SWIFT_POINTER, 0);
-                String typeName = utf8Chars.getString(0);
-                cFree(utf8Chars);
-                return typeName;
-            }
+        MethodHandle mh = swift_getTypeName.HANDLE;
+
+        try (Arena arena = Arena.ofConfined()) {
+            MemorySegment charsAndLength = (MemorySegment) mh.invokeExact((SegmentAllocator) arena, typeMetadata, qualified);
+            MemorySegment utf8Chars = charsAndLength.get(SwiftValueLayout.SWIFT_POINTER, 0);
+            String typeName = utf8Chars.getString(0);
+
+            // FIXME: this free is not always correct:
+            //      java(80175,0x17008f000) malloc: *** error for object 0x600000362610: pointer being freed was not allocated
+            // cFree(utf8Chars);
+
+            return typeName;
         } catch (Throwable ex$) {
             throw new AssertionError("should not reach here", ex$);
         }

SwiftKit/src/main/java/org/swift/swiftkit/SwiftMemoryResourceCleanup.java

@@ -22,7 +22,7 @@
 sealed interface SwiftMemoryResourceCleanup extends Runnable {
 }
 
-record SwiftHeapObjectCleanup(MemorySegment resource) implements SwiftMemoryResourceCleanup {
+record SwiftHeapObjectCleanup(SwiftHeapObject resource) implements SwiftMemoryResourceCleanup {
 
     @Override
     public void run() throws UnexpectedRetainCountException {
@@ -31,9 +31,10 @@ public void run() throws UnexpectedRetainCountException {
             throw new UnexpectedRetainCountException(this.resource, retainedCount, 1);
         }
 
-        SwiftKit.log.info("Destroy heap object: " + this.resource);
+        System.out.println("Cleanup heap object: " + this.resource);
+        var ty = this.resource.$swiftType();
 
-        SwiftValueWitnessTable.destroy(this.resource);
+        SwiftValueWitnessTable.destroy(ty, this.resource.$memorySegment());
     }
 }