Merge pull request #67599 from drexin/wip-112474091

[Runtime] Fix _swift_refCountBytesForMetatype for reference types

Author: drexin

stdlib/public/runtime/Metadata.cpp

@@ -2785,15 +2785,26 @@ size_t swift::_swift_refCountBytesForMetatype(const Metadata *type) {
     size_t offset = sizeof(uint64_t);
     return LayoutStringReader{type->getLayoutString(), offset}
         .readBytes<size_t>();
-  } else if (type->isClassObject() || type->isAnyExistentialType()) {
-    return sizeof(uint64_t);
   } else if (auto *tuple = dyn_cast<TupleTypeMetadata>(type)) {
     size_t res = 0;
     for (InProcess::StoredSize i = 0; i < tuple->NumElements; i++) {
       res += _swift_refCountBytesForMetatype(tuple->getElement(i).Type);
     }
     return res;
+  } else if (auto *cls = type->getClassObject()) {
+    if (cls->isTypeMetadata()) {
+      auto *vwt = cls->getValueWitnesses();
+      if (vwt != &VALUE_WITNESS_SYM(Bo) &&
+          vwt != &VALUE_WITNESS_SYM(BO) &&
+          vwt != &VALUE_WITNESS_SYM(Bb)) {
+        goto metadata;
+      }
+    }
+    return sizeof(uint64_t);
+  } else if (type->isAnyExistentialType()) {
+    return sizeof(uint64_t);
   } else {
+  metadata:
     return sizeof(uint64_t) + sizeof(uintptr_t);
   }
 }

test/Interpreter/Inputs/ObjCClasses/ObjCClasses.h

@@ -118,6 +118,9 @@ __attribute__((swift_name("OuterType.InnerType")))
 @property NSArray<OuterType *> *things;
 @end
 
+@interface ObjCPrintOnDealloc : NSObject
+@end
+
 NS_ASSUME_NONNULL_END
 
 #endif

test/Interpreter/Inputs/ObjCClasses/ObjCClasses.m

@@ -191,3 +191,9 @@ - (id)init {
 }
 
 @end
+
+@implementation ObjCPrintOnDealloc
+- (void)dealloc {
+  printf("ObjCPrintOnDealloc deinitialized!\n");
+}
+@end

test/Interpreter/Inputs/layout_string_witnesses_types.swift

@@ -276,6 +276,16 @@ public struct Wrapper<T> {
     }
 }
 
+public struct NestedWrapper<T> {
+    public let x: Wrapper<T>
+    public let y: Wrapper<T>
+
+    public init(x: Wrapper<T>, y: Wrapper<T>) {
+        self.x = x
+        self.y = y
+    }
+}
+
 struct InternalGeneric<T> {
     let x: T
     let y: Int

test/Interpreter/layout_string_witnesses_objc.swift

@@ -0,0 +1,46 @@
+// RUN: %empty-directory(%t)
+//
+// RUN: %target-clang -fobjc-arc %S/Inputs/ObjCClasses/ObjCClasses.m -c -o %t/ObjCClasses.o
+// RUN: %target-swift-frontend -prespecialize-generic-metadata -enable-experimental-feature LayoutStringValueWitnesses -enable-experimental-feature LayoutStringValueWitnessesInstantiation -enable-layout-string-value-witnesses -enable-layout-string-value-witnesses-instantiation -enable-type-layout -enable-autolinking-runtime-compatibility-bytecode-layouts -parse-stdlib -emit-module -emit-module-path=%t/layout_string_witnesses_types.swiftmodule %S/Inputs/layout_string_witnesses_types.swift
+// RUN: %target-build-swift-dylib(%t/%target-library-name(layout_string_witnesses_types)) -Xfrontend -enable-experimental-feature -Xfrontend LayoutStringValueWitnesses -Xfrontend -enable-experimental-feature -Xfrontend LayoutStringValueWitnessesInstantiation -Xfrontend -enable-layout-string-value-witnesses -Xfrontend -enable-layout-string-value-witnesses-instantiation -Xfrontend -enable-type-layout -Xfrontend -parse-stdlib -parse-as-library %S/Inputs/layout_string_witnesses_types.swift
+// RUN: %target-build-swift -g -Xfrontend -enable-experimental-feature -Xfrontend LayoutStringValueWitnesses -Xfrontend -enable-experimental-feature -Xfrontend LayoutStringValueWitnessesInstantiation -Xfrontend -enable-layout-string-value-witnesses -Xfrontend -enable-layout-string-value-witnesses-instantiation -Xfrontend -enable-type-layout -parse-stdlib -module-name layout_string_witnesses_dynamic -llayout_string_witnesses_types -L%t -I %S/Inputs/ObjCClasses/ %t/ObjCClasses.o -I %t -o %t/main %s %target-rpath(%t)
+// RUN: %target-codesign %t/main
+// RUN: %target-run %t/main %t/%target-library-name(layout_string_witnesses_types) | %FileCheck %s --check-prefix=CHECK -check-prefix=CHECK-%target-os
+
+// REQUIRES: executable_test
+// REQUIRES: objc_interop
+
+import Swift
+import layout_string_witnesses_types
+import ObjCClasses
+import Foundation
+
+func testNestedResilientObjc() {
+    let ptr = allocateInternalGenericPtr(of: NestedWrapper<ObjCPrintOnDealloc>.self)
+
+    do {
+        let x = NestedWrapper<ObjCPrintOnDealloc>(x: .init(x: ObjCPrintOnDealloc()), y: .init(x: ObjCPrintOnDealloc()))
+        testGenericInit(ptr, to: x)
+    }
+
+    do {
+        let y = NestedWrapper<ObjCPrintOnDealloc>(x: .init(x: ObjCPrintOnDealloc()), y: .init(x: ObjCPrintOnDealloc()))
+        // CHECK-macosx: Before deinit
+        print("Before deinit")
+
+        // CHECK-macosx-NEXT: ObjCPrintOnDealloc deinitialized!
+        // CHECK-macosx-NEXT: ObjCPrintOnDealloc deinitialized!
+        testGenericAssign(ptr, from: y)
+    }
+
+    // CHECK-macosx-NEXT: Before deinit
+    print("Before deinit")
+
+    // CHECK-macosx-NEXT: ObjCPrintOnDealloc deinitialized!
+    // CHECK-macosx-NEXT: ObjCPrintOnDealloc deinitialized!
+    testGenericDestroy(ptr, of: NestedWrapper<ObjCPrintOnDealloc>.self)
+
+    ptr.deallocate()
+}
+
+testNestedResilientObjc()