use unsafeBitCast to avoid dropping to C to cast OpaquePointers

Author: dgrove-oss

src/swift/DispatchStubs.cc

@@ -15,7 +15,7 @@
 
 #define DISPATCH_RUNTIME_STDLIB_INTERFACE __attribute__((__visibility__("default")))
 
-#if 0
+#if USE_OBJC
 @protocol OS_dispatch_source;
 @protocol OS_dispatch_source_mach_send;
 @protocol OS_dispatch_source_mach_recv;
@@ -49,9 +49,9 @@ static void _dispatch_overlay_constructor() {
   }
 }
 
-#endif
+#endif /* USE_OBJC */
 
-#if 0
+#if 0 /* FIXME -- adding directory to include path may need build-script plumbing to do properly... */
 #include "swift/Runtime/Config.h"
 #else
 #define SWIFT_CC(x) /* FIXME!! */
@@ -161,19 +161,6 @@ _swift_dispatch_sync(dispatch_queue_t queue, dispatch_block_t block) {
   dispatch_sync(queue, block);
 }
 
-#define PUN(t)                                                                \
-SWIFT_CC(swift) DISPATCH_RUNTIME_STDLIB_INTERFACE                             \
-extern "C" dispatch_object_t                                                  \
-_dispatch_pun_##t##_to_object(dispatch_##t##_t obj) {                         \
-  return (dispatch_object_t)obj;                                              \
-}
-
-PUN(group)
-PUN(semaphore)
-PUN(io)
-PUN(queue)
-PUN(source)
-
 // DISPATCH_RUNTIME_STDLIB_INTERFACE
 // extern "C" dispatch_queue_t
 // _swift_apply_current_root_queue() {

src/swift/Wrapper.swift

@@ -44,7 +44,7 @@ public class DispatchGroup : DispatchObject {
 	internal let __wrapped:dispatch_group_t;
 
 	internal override func wrapped() -> dispatch_object_t {
-		return _dispatch_pun_group_to_object(__wrapped)
+		return unsafeBitCast(__wrapped, to: dispatch_object_t.self)
 	}
 
 	public override init() {
@@ -64,7 +64,7 @@ public class DispatchSemaphore : DispatchObject {
 	internal let __wrapped: dispatch_semaphore_t;
 
 	internal override func wrapped() -> dispatch_object_t {
-		return _dispatch_pun_semaphore_to_object(__wrapped)
+		return unsafeBitCast(__wrapped, to: dispatch_object_t.self)
 	}
 
 	public init(value: Int) {
@@ -76,7 +76,7 @@ public class DispatchIO : DispatchObject {
 	internal let __wrapped:dispatch_io_t
 
 	internal override func wrapped() -> dispatch_object_t {
-		return _dispatch_pun_io_to_object(__wrapped)
+		return unsafeBitCast(__wrapped, to: dispatch_object_t.self)
 	}
 
 	internal init(__type: UInt, fd: Int32, queue: DispatchQueue,
@@ -117,7 +117,7 @@ public class DispatchQueue : DispatchObject {
 	internal let __wrapped:dispatch_queue_t;
 
 	internal override func wrapped() -> dispatch_object_t {
-		return _dispatch_pun_queue_to_object(__wrapped)
+		return unsafeBitCast(__wrapped, to: dispatch_object_t.self)
 	}
 
 	internal init(__label: String, attr: dispatch_queue_attr_t?) {
@@ -145,7 +145,7 @@ public class DispatchSource : DispatchObject,
 	internal let __wrapped:dispatch_source_t
 
 	internal override func wrapped() -> dispatch_object_t {
-		return _dispatch_pun_source_to_object(__wrapped)
+		return unsafeBitCast(__wrapped, to: dispatch_object_t.self)
 	}
 
 	internal init(source:dispatch_source_t) {
@@ -281,19 +281,3 @@ internal enum _OSQoSClass : UInt32  {
 		}
 	}
 }
-
-
-@_silgen_name("_dispatch_pun_group_to_object")
-internal func _dispatch_pun_group_to_object(_ group:dispatch_group_t) -> dispatch_object_t
-
-@_silgen_name("_dispatch_pun_semaphore_to_object")
-internal func _dispatch_pun_semaphore_to_object(_ semaphore:dispatch_semaphore_t) -> dispatch_object_t
-
-@_silgen_name("_dispatch_pun_io_to_object")
-internal func _dispatch_pun_io_to_object(_ io:dispatch_io_t) -> dispatch_object_t
-
-@_silgen_name("_dispatch_pun_queue_to_object")
-internal func _dispatch_pun_queue_to_object(_ queue:dispatch_queue_t) -> dispatch_object_t
-
-@_silgen_name("_dispatch_pun_source_to_object")
-internal func _dispatch_pun_source_to_object(_ source:dispatch_source_t) -> dispatch_object_t