[SR-7263] Treat APIs returning unmanaged CF types as NS_RETURNS_INNER_POINTER

Author: ChristopherRogers

lib/SIL/SILFunctionType.cpp

@@ -1456,6 +1456,11 @@ class ObjCMethodConventions : public Conventions {
     if (tl.isTrivial()) {
       if (Method->hasAttr<clang::ObjCReturnsInnerPointerAttr>())
         return ResultConvention::UnownedInnerPointer;
+
+      auto type = tl.getLoweredType();
+      if (type.unwrapOptionalType().getStructOrBoundGenericStruct()
+          == type.getASTContext().getUnmanagedDecl())
+        return ResultConvention::UnownedInnerPointer;
       return ResultConvention::Unowned;
     }
 

test/SILGen/cf.swift

@@ -29,7 +29,7 @@ func useEmAll(_ model: CCMagnetismModel) {
 // CHECK: function_ref @CCRefrigeratorDestroy : $@convention(c) (@owned Optional<CCRefrigerator>) -> ()
   CCRefrigeratorDestroy(clone)
 
-// CHECK: objc_method [[ARG]] : $CCMagnetismModel, #CCMagnetismModel.refrigerator!1.foreign : (CCMagnetismModel) -> () -> Unmanaged<CCRefrigerator>?, $@convention(objc_method) (CCMagnetismModel) -> Optional<Unmanaged<CCRefrigerator>>
+// CHECK: objc_method [[ARG]] : $CCMagnetismModel, #CCMagnetismModel.refrigerator!1.foreign : (CCMagnetismModel) -> () -> Unmanaged<CCRefrigerator>?, $@convention(objc_method) (CCMagnetismModel) -> @unowned_inner_pointer Optional<Unmanaged<CCRefrigerator>>
   let f0 = model.refrigerator()
 
 // CHECK: objc_method [[ARG]] : $CCMagnetismModel, #CCMagnetismModel.getRefrigerator!1.foreign : (CCMagnetismModel) -> () -> CCRefrigerator?, $@convention(objc_method) (CCMagnetismModel) -> @autoreleased Optional<CCRefrigerator>