[cxx-interop] Support ObjC classes in generic context in reverse interop

lib/PrintAsClang/ModuleContentsWriter.cpp

@@ -35,6 +35,7 @@
 #include "swift/Strings.h"
 
 #include "clang/AST/Decl.h"
+#include "clang/AST/DeclObjC.h"
 #include "clang/Basic/Module.h"
 
 #include "llvm/Support/raw_ostream.h"
@@ -285,10 +286,20 @@ class ModuleWriter {
   }
 
   void emitReferencedClangTypeMetadata(const TypeDecl *typeDecl) {
-    if (!isa<clang::TypeDecl>(typeDecl->getClangDecl()))
+    const auto *clangDecl = typeDecl->getClangDecl();
+    if (const auto *objCInt = dyn_cast<clang::ObjCInterfaceDecl>(clangDecl)) {
+      auto clangType = clangDecl->getASTContext()
+                           .getObjCInterfaceType(objCInt)
+                           .getCanonicalType();
+      auto it = seenClangTypes.insert(clangType.getTypePtr());
+      if (it.second)
+        ClangValueTypePrinter::printClangTypeSwiftGenericTraits(os, typeDecl, &M,
+                                                                printer);
+      return;
+    }
+    if (!isa<clang::TypeDecl>(clangDecl))
       return;
     // Get the underlying clang type from a type alias decl or record decl.
-    auto clangDecl = typeDecl->getClangDecl();
     auto clangType = clangDecl->getASTContext()
                          .getTypeDeclType(cast<clang::TypeDecl>(clangDecl))
                          .getCanonicalType();
@@ -314,6 +325,8 @@ class ModuleWriter {
           forwardDeclareCxxValueTypeIfNeeded(NTD);
         else if (isa<StructDecl>(TD) && NTD->hasClangNode())
           emitReferencedClangTypeMetadata(NTD);
+        else if (isa<ClassDecl>(TD) && TD->isObjC()) 
+          emitReferencedClangTypeMetadata(NTD);
       } else if (auto TAD = dyn_cast<TypeAliasDecl>(TD)) {
         if (TAD->hasClangNode())
           emitReferencedClangTypeMetadata(TAD);

lib/PrintAsClang/PrintClangValueType.cpp

@@ -641,6 +641,7 @@ void ClangValueTypePrinter::printTypeGenericTraits(
               typeDecl, typeMetadataFuncName, typeMetadataFuncRequirements);
         });
   }
+  bool addPointer = typeDecl->isObjC();
 
   os << "#pragma clang diagnostic push\n";
   os << "#pragma clang diagnostic ignored \"-Wc++17-extensions\"\n";
@@ -649,6 +650,8 @@ void ClangValueTypePrinter::printTypeGenericTraits(
     os << "template<>\n";
     os << "inline const constexpr bool isUsableInGenericContext<";
     printer.printClangTypeReference(typeDecl->getClangDecl());
+    if (addPointer)
+      os << "*";
     os << "> = true;\n";
   }
   if (!NTD || printer.printNominalTypeOutsideMemberDeclTemplateSpecifiers(NTD))
@@ -658,6 +661,8 @@ void ClangValueTypePrinter::printTypeGenericTraits(
   os << " TypeMetadataTrait<";
   if (typeDecl->hasClangNode()) {
     printer.printClangTypeReference(typeDecl->getClangDecl());
+    if (addPointer)
+      os << "*";
   } else {
     assert(NTD);
     printer.printNominalTypeReference(NTD,
@@ -682,7 +687,7 @@ void ClangValueTypePrinter::printTypeGenericTraits(
 
   os << "namespace " << cxx_synthesis::getCxxImplNamespaceName() << "{\n";
 
-  if (typeDecl->hasClangNode()) {
+  if (typeDecl->hasClangNode() && !typeDecl->isObjC()) {
     os << "template<>\n";
     os << "inline const constexpr bool isSwiftBridgedCxxRecord<";
     printer.printClangTypeReference(typeDecl->getClangDecl());

test/Interop/ObjCToSwiftToObjCxx/bridge-objc-types-back-to-objcxx-execution.mm

@@ -86,6 +86,10 @@ public func retObjCProtocolNullable() -> ObjCProtocol? {
     return ObjCKlassConforming(2)
 }
 
+public func retObjClassArray() -> [ObjCKlass] {
+    return [ObjCKlass(1)]
+}
+
 //--- use-swift-objc-types.mm
 
 #include "header.h"
@@ -188,5 +192,14 @@ int main() {
 // CHECK-NEXT: ObjCKlassConforming: 2
 // CHECK-NEXT: destroy ObjCKlassConforming
 // DESTROY: destroy ObjCKlassConforming
+  puts("Part4");
+  @autoreleasepool {
+    swift::Array<ObjCKlass*> val = retObjClassArray();
+    assert(val[0].getValue == 1);
+    assert(globalCounter == 1);
+  }
+  assert(globalCounter == 0);
+// CHECK: create ObjCKlass
+// DESTROY: destroy ObjCKlass
   return 0;
 }

test/Interop/ObjCToSwiftToObjCxx/bridge-objc-types-back-to-objcxx.swift

@@ -69,6 +69,10 @@ public func retObjCProtocolNullable() -> ObjCProtocol? {
     return nil
 }
 
+public func retObjCClassArray() -> [ObjCKlass] {
+    return []
+}
+
 // CHECK: SWIFT_EXTERN id <ObjCProtocol> _Nonnull $s9UseObjCTy03retB9CProtocolSo0bE0_pyF(void) SWIFT_NOEXCEPT SWIFT_CALL; // retObjCProtocol()
 // CHECK-NEXT: #endif
 // CHECK-NEXT: #if defined(__OBJC__)
@@ -86,6 +90,14 @@ public func retObjCProtocolNullable() -> ObjCProtocol? {
 // CHECK-NEXT: SWIFT_EXTERN void $s9UseObjCTy04takeB17CProtocolNullableyySo0bE0_pSgF(id <ObjCProtocol> _Nullable x) SWIFT_NOEXCEPT SWIFT_CALL; // takeObjCProtocolNullable(_:)
 // CHECK-NEXT: #endif
 
+// CHECK: inline const constexpr bool isUsableInGenericContext<ObjCKlass*> = true;
+// CHECK-NEXT: template<>
+// CHECK-NEXT: struct TypeMetadataTrait<ObjCKlass*> {
+// CHECK-NEXT:   static SWIFT_INLINE_PRIVATE_HELPER void * _Nonnull getTypeMetadata() {
+// CHECK-NEXT:     return _impl::$sSo9ObjCKlassCMa(0)._0;
+// CHECK-NEXT:   }
+// CHECK-NEXT: };
+
 // CHECK: #if defined(__OBJC__)
 // CHECK-NEXT: SWIFT_INLINE_THUNK id <ObjCProtocol> _Nonnull retObjCProtocol() noexcept SWIFT_SYMBOL("s:9UseObjCTy03retB9CProtocolSo0bE0_pyF") SWIFT_WARN_UNUSED_RESULT {
 // CHECK-NEXT:  return (__bridge_transfer id <ObjCProtocol>)(__bridge void *)UseObjCTy::_impl::$s9UseObjCTy03retB9CProtocolSo0bE0_pyF();