diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -2130,6 +2130,12 @@
   let ASTNode = 0;
 }
 
+def SwiftObjCMembers : Attr {
+  let Spellings = [GNU<"swift_objc_members">];
+  let Subjects = SubjectList<[ObjCInterface], ErrorDiag>;
+  let Documentation = [SwiftObjCMembersDocs];
+}
+
 def SwiftError : InheritableAttr {
   let Spellings = [GNU<"swift_error">];
   let Args = [
diff --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -3476,6 +3476,16 @@
   }];
 }
 
+def SwiftObjCMembersDocs : Documentation {
+  let Category = SwiftDocs;
+  let Heading = "swift_objc_members";
+  let Content = [{
+This attribute indicates that Swift subclasses and members of Swift extensions
+of this class will be implicitly marked with the ``@objcMembers`` Swift
+attribute, exposing them back to Objective-C.
+  }];
+}
+
 def SwiftErrorDocs : Documentation {
   let Category = SwiftDocs;
   let Heading = "swift_error";
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -7536,6 +7536,9 @@
   case ParsedAttr::AT_SwiftError:
     handleSwiftError(S, D, AL);
     break;
+  case ParsedAttr::AT_SwiftObjCMembers:
+    handleSimpleAttribute<SwiftObjCMembersAttr>(S, D, AL);
+    break;
 
   // XRay attributes.
   case ParsedAttr::AT_XRayLogArgs:
diff --git a/clang/test/Misc/pragma-attribute-supported-attributes-list.test b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
--- a/clang/test/Misc/pragma-attribute-supported-attributes-list.test
+++ b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
@@ -150,6 +150,7 @@
 // CHECK-NEXT: SwiftError (SubjectMatchRule_function, SubjectMatchRule_objc_method)
 // CHECK-NEXT: SwiftErrorResult (SubjectMatchRule_variable_is_parameter)
 // CHECK-NEXT: SwiftIndirectResult (SubjectMatchRule_variable_is_parameter)
+// CHECK-NEXT: SwiftObjCMembers (SubjectMatchRule_objc_interface)
 // CHECK-NEXT: TLSModel (SubjectMatchRule_variable_is_thread_local)
 // CHECK-NEXT: Target (SubjectMatchRule_function)
 // CHECK-NEXT: TestTypestate (SubjectMatchRule_function_is_member)
diff --git a/clang/test/SemaObjC/attr-swift_objc_members.m b/clang/test/SemaObjC/attr-swift_objc_members.m
new file mode 100644
--- /dev/null
+++ b/clang/test/SemaObjC/attr-swift_objc_members.m
@@ -0,0 +1,24 @@
+// RUN: %clang_cc1 -verify -fsyntax-only %s
+
+#if !__has_attribute(swift_objc_members)
+#error cannot verify presence of swift_objc_members attribute
+#endif
+
+__attribute__((__swift_objc_members__))
+__attribute__((__objc_root_class__))
+@interface I
+@end
+
+__attribute__((swift_objc_members))
+@protocol P
+@end
+// expected-error@-3 {{'swift_objc_members' attribute only applies to Objective-C interfaces}}
+
+__attribute__((swift_objc_members))
+extern void f(void);
+// expected-error@-2 {{'swift_objc_members' attribute only applies to Objective-C interfaces}}
+
+// expected-error@+1 {{'__swift_objc_members__' attribute takes no arguments}}
+__attribute__((__swift_objc_members__("J")))
+@interface J
+@end