[IRGen] Don't call objc_retainAutoreleasedReturnValue() without interop.

When ObjC interop is not enabled, we shouldn't be emitting calls to
`objc_retainAutoreleasedReturnValue()` as that function might not exist.

Call `swift_retain()` instead, to balance the `swift_release()` of the
returned value.

Fixes #47846, #45359.

rdar://23335318

Author: al45tair

lib/IRGen/GenCall.cpp

@@ -2605,7 +2605,10 @@ class SyncCallEmission final : public CallEmission {
     if (fnConv.getNumDirectSILResults() == 1
         && (fnConv.getDirectSILResults().begin()->getConvention()
             == ResultConvention::Autoreleased)) {
-      result = emitObjCRetainAutoreleasedReturnValue(IGF, result);
+      if (IGF.IGM.Context.LangOpts.EnableObjCInterop)
+        result = emitObjCRetainAutoreleasedReturnValue(IGF, result);
+      else
+        IGF.emitNativeStrongRetain(result, IGF.getDefaultAtomicity());
     }
 
     auto origFnType = getCallee().getOrigFunctionType();

test/IRGen/Inputs/CFBridgedType.h

@@ -0,0 +1,6 @@
+#define CF_BRIDGED_TYPE(T) __attribute__((objc_bridge(T)))
+
+typedef struct CF_BRIDGED_TYPE(id) __CFBridgedType *CFBridgedTypeRef;
+
+__attribute__((cf_audited_transfer))
+CFBridgedTypeRef returnsACFBridgedType(void);

test/IRGen/Inputs/module.modulemap

@@ -33,5 +33,9 @@ module SynthesizedProtocol {
 }
 
 module PointerAuth {
-   header "ptrauth_field_fptr_import.h"
- }
+  header "ptrauth_field_fptr_import.h"
+}
+
+module CFBridgedType {
+  header "CFBridgedType.h"
+}

test/IRGen/autorelease.sil

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %s -emit-ir | %FileCheck -check-prefix CHECK -check-prefix CHECK-%target-ptrsize -check-prefix %target-cpu -DINT=i%target-ptrsize %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) %s -enable-objc-interop -emit-ir | %FileCheck -check-prefix CHECK -check-prefix CHECK-%target-ptrsize -check-prefix %target-cpu -DINT=i%target-ptrsize %s
 
 // rdar://16565958
 

test/IRGen/cf_objc_retainAutoreleasedReturnValue.swift

@@ -0,0 +1,24 @@
+// RUN: %target-swift-frontend -module-name cf_objc_retainAutoreleasedReturnValue -I %S/Inputs %s -enable-objc-interop -emit-ir | %FileCheck %s
+// RUN: %target-swift-frontend -module-name cf_objc_retainAutoreleasedReturnValue -I %S/Inputs %s -emit-ir | %FileCheck %s --check-prefix=NO_INTEROP
+
+import CFBridgedType
+
+@inline(never)
+public func foo() {
+  let _ = returnsACFBridgedType()
+}
+
+// With interop enabled, this should use objc_retainAutoreleasedReturnValue()
+
+// CHECK-LABEL: define protected swiftcc void @"$s37cf_objc_retainAutoreleasedReturnValue3fooyyF"()
+// CHECK: entry:
+// CHECK:   %0 = call {{.*}}@returnsACFBridgedType()
+// CHECK:   %1 = notail call ptr @llvm.objc.retainAutoreleasedReturnValue(ptr %0)
+
+// Without interop, it should call swift_retain() instead.
+
+// NO_INTEROP-LABEL: define protected swiftcc void @"$s37cf_objc_retainAutoreleasedReturnValue3fooyyF"()
+// NO_INTEROP: entry:
+// NO_INTEROP:   %0 = call {{.*}}@returnsACFBridgedType()
+// NO_INTEROP:   %1 = call ptr @swift_retain(ptr returned %0)
+