[interop][SwiftToCxx] class bridging: use makeRetained to return a class value from Swift

Author: hyp

lib/PrintAsClang/PrintClangClassType.cpp

@@ -70,7 +70,7 @@ void ClangClassTypePrinter::printClassTypeDecl(
         os << "public:\n";
         os << "static inline ";
         printer.printBaseName(typeDecl);
-        os << " fromUnretained(void * _Nonnull ptr) noexcept { return ";
+        os << " makeRetained(void * _Nonnull ptr) noexcept { return ";
         printer.printBaseName(typeDecl);
         os << "(ptr); }\n";
         os << "};\n";
@@ -85,7 +85,7 @@ void ClangClassTypePrinter::printClassTypeReturnScaffold(
       type->getModuleContext(), moduleContext);
   os << cxx_synthesis::getCxxImplNamespaceName() << "::";
   ClangValueTypePrinter::printCxxImplClassName(os, type);
-  os << "::fromUnretained(";
+  os << "::makeRetained(";
   bodyPrinter();
   os << ");\n";
 }

test/Interop/SwiftToCxx/class/swift-class-in-cxx.swift

@@ -43,7 +43,7 @@ public final class ClassWithIntField {
 // CHECK-EMPTY:
 // CHECK-NEXT:class _impl_ClassWithIntField {
 // CHECK-NEXT:public:
-// CHECK-NEXT:static inline ClassWithIntField fromUnretained(void * _Nonnull ptr) noexcept { return ClassWithIntField(ptr); }
+// CHECK-NEXT:static inline ClassWithIntField makeRetained(void * _Nonnull ptr) noexcept { return ClassWithIntField(ptr); }
 // CHECK-NEXT:};
 // CHECK-EMPTY:
 // CHECK-NEXT:} // namespace _impl
@@ -57,5 +57,5 @@ public func returnClassWithIntField() -> ClassWithIntField {
 }
 
 // CHECK: inline ClassWithIntField returnClassWithIntField() noexcept SWIFT_WARN_UNUSED_RESULT {
-// CHECK-NEXT:   return _impl::_impl_ClassWithIntField::fromUnretained(_impl::$s5Class06returnA12WithIntFieldAA0acdE0CyF());
+// CHECK-NEXT:   return _impl::_impl_ClassWithIntField::makeRetained(_impl::$s5Class06returnA12WithIntFieldAA0acdE0CyF());
 // CHECK-NEXT: }