Partially revert a4814df

Author: kateinoigakukun

include/swift/Runtime/HeapObject.h

@@ -194,13 +194,10 @@ void swift_nonatomic_release_n(HeapObject *object, uint32_t n);
 
 // Refcounting observation hooks for memory tools. Don't use these.
 SWIFT_RUNTIME_EXPORT
-SWIFT_CC(swift)
 size_t swift_retainCount(HeapObject *object);
 SWIFT_RUNTIME_EXPORT
-SWIFT_CC(swift)
 size_t swift_unownedRetainCount(HeapObject *object);
 SWIFT_RUNTIME_EXPORT
-SWIFT_CC(swift)
 size_t swift_weakRetainCount(HeapObject *object);
 
 /// Is this pointer a non-null unique reference to an object?

stdlib/public/SwiftShims/swift/shims/HeapObject.h

@@ -81,25 +81,17 @@ struct HeapObject {
 #ifdef __cplusplus
 extern "C" {
 #endif
-#if __has_attribute(swiftcall)
-#define SWIFT_CC_swift __attribute__((swiftcall))
-#else
-#define SWIFT_CC_swift
-#endif
 
 SWIFT_RUNTIME_STDLIB_API
 void _swift_instantiateInertHeapObject(void *address,
                                        const HeapMetadata *metadata);
 
-SWIFT_CC_swift
 SWIFT_RUNTIME_STDLIB_API
 __swift_size_t swift_retainCount(HeapObject *obj);
 
-SWIFT_CC_swift
 SWIFT_RUNTIME_STDLIB_API
 __swift_size_t swift_unownedRetainCount(HeapObject *obj);
 
-SWIFT_CC_swift
 SWIFT_RUNTIME_STDLIB_API
 __swift_size_t swift_weakRetainCount(HeapObject *obj);