[interop][SwiftToCxx] support interop with FRT in the generated C++ bindings

Author: hyp

lib/PrintAsClang/PrintClangFunction.cpp

@@ -268,13 +268,13 @@ class CFunctionSignatureTypePrinter
                                      bool isInOutParam) {
     auto *cd = CT->getDecl();
     if (cd->hasClangNode()) {
-      ClangSyntaxPrinter(os).printIdentifier(
-          cast<clang::NamedDecl>(cd->getClangDecl())->getName());
+      ClangSyntaxPrinter(os).printNominalClangTypeReference(cd->getClangDecl());
       os << " *"
          << (!optionalKind || *optionalKind == OTK_None ? "_Nonnull"
                                                         : "_Nullable");
       if (isInOutParam) {
-        os << " __strong";
+        if (isa<clang::ObjCContainerDecl>(cd->getClangDecl()))
+          os << " __strong";
         printInoutTypeModifier();
       }
       // FIXME: Mark that this is only ObjC representable.
@@ -1151,7 +1151,13 @@ void DeclAndTypeClangFunctionPrinter::printCxxThunkBody(
       return;
     }
     if (auto *classDecl = resultTy->getClassOrBoundGenericClass()) {
-      assert(!classDecl->hasClangNode());
+      if (classDecl->hasClangNode()) {
+        assert(!isa<clang::ObjCContainerDecl>(classDecl->getClangDecl()));
+        os << "return ";
+        printCallToCFunc(/*additionalParam=*/None);
+        os << ";\n";
+        return;
+      }
       ClangClassTypePrinter::printClassTypeReturnScaffold(
           os, classDecl, moduleContext,
           [&]() { printCallToCFunc(/*additionalParam=*/None); });

test/Interop/CxxToSwiftToCxx/bridge-cxx-struct-back-to-cxx.swift

@@ -44,6 +44,29 @@ namespace ns {
     struct NonTrivialImplicitMove {
         NonTrivialTemplate<int> member;
     };
+
+    #define IMMORTAL_REF                                \
+         __attribute__((swift_attr("import_as_ref")))   \
+         __attribute__((swift_attr("retain:immortal"))) \
+         __attribute__((swift_attr("release:immortal")))
+    struct IMMORTAL_REF Immortal {
+    public:
+    };
+
+    inline Immortal *makeNewImmortal() {
+        return new Immortal;
+    }
+
+    template<class T>
+    struct IMMORTAL_REF ImmortalTemplate {
+    public:
+    };
+
+    inline ImmortalTemplate<int> *makeNewImmortalInt() {
+        return new ImmortalTemplate<int>;
+    }
+
+    using ImmortalCInt = ImmortalTemplate<int>;
 }
 
 //--- module.modulemap
@@ -55,6 +78,16 @@ module CxxTest {
 //--- use-cxx-types.swift
 import CxxTest
 
+@_expose(Cxx)
+public func retImmortal() -> ns.Immortal {
+    return ns.makeNewImmortal()
+}
+
+@_expose(Cxx)
+public func retImmortalTemplate() -> ns.ImmortalCInt {
+    return ns.makeNewImmortalInt()
+}
+
 @_expose(Cxx)
 public func retNonTrivial() -> ns.NonTrivialTemplate<CInt> {
     return ns.NonTrivialTemplate<CInt>()
@@ -80,6 +113,14 @@ public func retTrivial() -> Trivial {
     return Trivial()
 }
 
+@_expose(Cxx)
+public func takeImmortal(_ x: ns.Immortal) {
+}
+
+@_expose(Cxx)
+public func takeImmortalTemplate(_ x: ns.ImmortalCInt) {
+}
+
 @_expose(Cxx)
 public func takeNonTrivial2(_ x: ns.NonTrivialTemplate<ns.TrivialinNS>) {
 }
@@ -104,6 +145,14 @@ public func takeTrivialInout(_ x: inout Trivial) {
 // CHECK: SWIFT_EXTERN void $s8UseCxxTy13retNonTrivialSo2nsO02__b18TemplateInstN2ns18efH4IiEEVyF(SWIFT_INDIRECT_RESULT void * _Nonnull) SWIFT_NOEXCEPT SWIFT_CALL; // retNonTrivial()
 // CHECK: SWIFT_EXTERN struct swift_interop_returnStub_UseCxxTy_uint32_t_0_4 $s8UseCxxTy10retTrivialSo0E0VyF(void) SWIFT_NOEXCEPT SWIFT_CALL; // retTrivial()
 
+// CHECK: ns::Immortal *_Nonnull retImmortal() noexcept SWIFT_WARN_UNUSED_RESULT {
+// CHECK-NEXT: return _impl::$s8UseCxxTy11retImmortalSo2nsO0E0VyF();
+// CHECK-NEXT: }
+
+// CHECK:  ns::ImmortalTemplate<int> *_Nonnull retImmortalTemplate() noexcept SWIFT_WARN_UNUSED_RESULT {
+// CHECK-NEXT: return _impl::$s8UseCxxTy19retImmortalTemplateSo2nsO02__bf10InstN2ns16eF4IiEEVyF();
+// CHECK-NEXT: }
+
 // CHECK: } // end namespace
 // CHECK-EMPTY:
 // CHECK-NEXT: namespace swift {
@@ -200,6 +249,14 @@ public func takeTrivialInout(_ x: inout Trivial) {
 // CHECK-NEXT: return *storageObjectPtr;
 // CHECK-NEXT: }
 
+// CHECK: void takeImmortal(ns::Immortal *_Nonnull x) noexcept {
+// CHECK-NEXT: return _impl::$s8UseCxxTy12takeImmortalyySo2nsO0E0VF(x);
+// CHECK-NEXT: }
+
+// CHECK: void takeImmortalTemplate(ns::ImmortalTemplate<int> *_Nonnull x) noexcept {
+// CHECK-NEXT:   return _impl::$s8UseCxxTy20takeImmortalTemplateyySo2nsO02__bf10InstN2ns16eF4IiEEVF(x);
+// CHECK-NEXT: }
+
 // CHECK: inline void takeNonTrivial2(const ns::NonTrivialTemplate<ns::TrivialinNS>& x) noexcept {
 // CHECK-NEXT:   return _impl::$s8UseCxxTy15takeNonTrivial2yySo2nsO02__b18TemplateInstN2ns18e7TrivialH20INS_11TrivialinNSEEEVF(swift::_impl::getOpaquePointer(x));
 // CHECK-NEXT: }