[embedded] Handle NULL IVarDestroyers, expand test

Author: kubamracek

stdlib/public/SwiftShims/swift/shims/EmbeddedShims.h

@@ -63,13 +63,15 @@ _swift_embedded_invoke_heap_object_destroy(void *object) {
 }
 
 static inline void
-_swift_embedded_invoke_heap_object_ivardestroyer(void *object, void *metadata) {
+_swift_embedded_invoke_heap_object_optional_ivardestroyer(void *object, void *metadata) {
   void **ivardestroyer_location = &((void **)metadata)[2];
+  if (*ivardestroyer_location) {
 #if __has_feature(ptrauth_calls)
-  (*(HeapObjectDestroyer __ptrauth(0, 1, 0xbbbf) *)ivardestroyer_location)(object);
+    (*(HeapObjectDestroyer __ptrauth(0, 1, 0xbbbf) *)ivardestroyer_location)(object);
 #else
-  (*(HeapObjectDestroyer *)ivardestroyer_location)(object);
+    (*(HeapObjectDestroyer *)ivardestroyer_location)(object);
 #endif
+  }
 }
 
 static inline void *_swift_embedded_get_heap_object_metadata_pointer(void *object) {

stdlib/public/core/EmbeddedRuntime.swift

@@ -24,8 +24,8 @@ public struct ClassMetadata {
 
   // There is no way to express the actual calling convention on this
   // function (swiftcc with 'self') currently, so let's use UnsafeRawPointer
-  // and a helper function in C (_swift_embedded_invoke_heap_object_ivardestroyer).
-  var ivarDestroyer: UnsafeRawPointer
+  // and a helper function in C (_swift_embedded_invoke_heap_object_optional_ivardestroyer).
+  var ivarDestroyer: UnsafeRawPointer?
 }
 
 public struct HeapObject {
@@ -129,7 +129,7 @@ public func swift_deallocPartialClassInstance(object: Builtin.RawPointer, metada
 func swift_deallocPartialClassInstance(object: UnsafeMutablePointer<HeapObject>, metadata: UnsafeMutablePointer<ClassMetadata>, allocatedSize: Int, allocatedAlignMask: Int) {
   var classMetadata = _swift_embedded_get_heap_object_metadata_pointer(object).assumingMemoryBound(to: ClassMetadata.self)
   while classMetadata != metadata {
-    _swift_embedded_invoke_heap_object_ivardestroyer(object, classMetadata)
+    _swift_embedded_invoke_heap_object_optional_ivardestroyer(object, classMetadata)
     guard let superclassMetadata = classMetadata.pointee.superclassMetadata else { break }
     classMetadata = superclassMetadata
   }

test/embedded/init-throwing.swift

@@ -22,16 +22,28 @@ public class Foo {
     }
 }
 
-_ = try? Foo(shouldThrow: true)
+public class Bar: Foo {
+  var value: Int = 17
+}
+
+public class Wibble: Bar {
+  var c: PrintingClass = .init()
+}
+
+_ = try? Wibble(shouldThrow: true)
 print("OK 1")
 // CHECK: PrintingClass.init
+// CHECK: PrintingClass.init
+// CHECK: PrintingClass.deinit
 // CHECK: PrintingClass.deinit
 // CHECK: OK 1
 
-_ = try? Foo(shouldThrow: false)
+_ = try? Wibble(shouldThrow: false)
 print("OK 2")
 // CHECK: PrintingClass.init
 // CHECK: PrintingClass.init
+// CHECK: PrintingClass.init
+// CHECK: PrintingClass.deinit
 // CHECK: PrintingClass.deinit
 // CHECK: PrintingClass.deinit
 // CHECK: OK 2