Merge pull request #35586 from DougGregor/objc-async-extended-type-descriptors

[Concurrency] Emit extended method type descriptors for @objc async methods

Author: DougGregor

lib/IRGen/GenObjC.cpp

@@ -1185,7 +1185,8 @@ irgen::emitObjCMethodDescriptorParts(IRGenModule &IGM,
   /// elements.
   CanSILFunctionType methodType = getObjCMethodType(IGM, method);
   descriptor.typeEncoding =
-      getObjCEncodingForMethod(IGM, methodType, /*extended*/ false, method);
+      getObjCEncodingForMethod(IGM, methodType, /*extended*/ method->hasAsync(),
+                               method);
 
   /// The third element is the method implementation pointer.
   if (!concrete) {

test/IRGen/objc_async_metadata.swift

@@ -0,0 +1,23 @@
+// RUN: %empty-directory(%t)
+// RUN: %build-irgen-test-overlays
+// RUN: %target-swift-frontend(mock-sdk: -sdk %S/Inputs -I %t) -enable-experimental-concurrency %s -emit-ir | %FileCheck %s
+
+// REQUIRES: OS=macosx
+// REQUIRES: concurrency
+// REQUIRES: objc_interop
+
+
+import Foundation
+
+// CHECK: [[ENCODE_ASYNC_STRING:@.*]] = private unnamed_addr constant [28 x i8] c"v24@0:8@?<v@?@\22NSString\22>16\00"
+// CHECK: [[ENCODE_ASYNC_THROWS_STRING:@.*]] = private unnamed_addr constant [38 x i8] c"v24@0:8@?<v@?@\22NSString\22@\22NSError\22>16\00"
+
+// CHECK: @_INSTANCE_METHODS__TtC19objc_async_metadata7MyClass = internal constant
+// CHECK-SAME: methodWithCompletionHandler:
+// CHECK-SAME: [[ENCODE_ASYNC_STRING]]
+// CHECK-SAME: throwingMethodWithCompletionHandler:
+// CHECK-SAME: [[ENCODE_ASYNC_THROWS_STRING]]
+class MyClass: NSObject {
+  @objc func method() async -> String { "" }
+  @objc func throwingMethod() async throws -> String { "" }
+}