[cxx-interop] Do not create copies of optionals of nullable pointers

In reverse interop, we create copies of values that will be consumed by
the Swift function. This is not necessary for pointers that are passed
as swift::Optional to Swift. These are layout compatible, and consuming
a pointer should not require us to do anything extra, hopefully ARC
would take care of all the details.

rdar://146855233

Author: Gabor Horvath

lib/PrintAsClang/PrintClangFunction.cpp

@@ -1322,7 +1322,9 @@ void DeclAndTypeClangFunctionPrinter::printCxxThunkBody(
   signature.visitParameterList(
       [&](const LoweredFunctionSignature::IndirectResultValue &) {},
       [&](const LoweredFunctionSignature::DirectParameter &param) {
-        if (isConsumedParameterInCaller(param.getConvention()))
+        if (isConsumedParameterInCaller(param.getConvention()) &&
+            !hasKnownOptionalNullableCxxMapping(
+                param.getParamDecl().getInterfaceType()))
           emitParamCopyForConsume(param.getParamDecl());
         ++paramIndex;
       },
@@ -1394,7 +1396,9 @@ void DeclAndTypeClangFunctionPrinter::printCxxThunkBody(
         },
         [&](const LoweredFunctionSignature::DirectParameter &param) {
           printParamUse(param.getParamDecl(), /*isIndirect=*/false,
-                        isConsumedParameterInCaller(param.getConvention()),
+                        isConsumedParameterInCaller(param.getConvention()) &&
+                            !hasKnownOptionalNullableCxxMapping(
+                                param.getParamDecl().getInterfaceType()),
                         encodeTypeInfo(param, moduleContext, typeMapping));
         },
         [&](const LoweredFunctionSignature::IndirectParameter &param) {
@@ -1756,11 +1760,13 @@ void DeclAndTypeClangFunctionPrinter::printCxxSubscriptAccessorMethod(
 bool DeclAndTypeClangFunctionPrinter::hasKnownOptionalNullableCxxMapping(
     Type type) {
   if (auto optionalObjectType = type->getOptionalObjectType()) {
-    if (optionalObjectType->getNominalOrBoundGenericNominal()) {
+    if (const auto *nominal =
+            optionalObjectType->getNominalOrBoundGenericNominal()) {
       if (auto typeInfo = typeMapping.getKnownCxxTypeInfo(
               optionalObjectType->getNominalOrBoundGenericNominal())) {
         return typeInfo->canBeNullable;
       }
+      return isa_and_nonnull<clang::ObjCInterfaceDecl>(nominal->getClangDecl());
     }
   }
   return false;

test/Interop/SwiftToObjCxx/optional-objc-class-in-obj-cxx.swift

@@ -0,0 +1,16 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-frontend %s -module-name UseCoreFoundation -enable-experimental-cxx-interop -clang-header-expose-decls=all-public -typecheck -verify -emit-clang-header-path %t/UseCoreFoundation.h
+// RUN: %target-interop-build-clangxx -std=gnu++20 -fobjc-arc -c -x objective-c++-header %t/UseCoreFoundation.h -o %t/o.o
+
+// REQUIRES: objc_interop
+
+import Foundation
+
+public class TestFoundationType {
+    private let _bundle: Bundle?
+
+    public init(resourcesBundle bundle: Bundle? = nil) {
+        _bundle = bundle
+    }
+}