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
@@ -2149,6 +2149,12 @@
   let ASTNode = 0;
 }
 
+def SwiftAttr : InheritableAttr {
+  let Spellings = [Clang<"swift_attr">];
+  let Args = [StringArgument<"Attribute">];
+  let Documentation = [SwiftAttrDocs];
+}
+
 def SwiftBridge : InheritableAttr {
   let Spellings = [GNU<"swift_bridge">];
   let Args = [StringArgument<"SwiftType">];
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
@@ -3628,6 +3628,18 @@
   }];
 }
 
+def SwiftAttrDocs : Documentation {
+  let Category = SwiftDocs;
+  let Heading = "swift_attr";
+  let Content = [{
+The ``swift_attr`` provides a Swift-specific annotation for the declaration
+to which the attribute appertains to. This kind of annotation is ignored by
+clang as it doesn't have any semantic meaning in languages supported by clang.
+The Swift compiler can interpret these annotations according to its own rules
+when importing C or Objective-C declarations.
+}];
+}
+
 def SwiftBridgeDocs : Documentation {
   let Category = SwiftDocs;
   let Heading = "swift_bridge";
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
@@ -5607,6 +5607,16 @@
   D->addAttr(::new (S.Context) ObjCPreciseLifetimeAttr(S.Context, AL));
 }
 
+static void handleSwiftAttrAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
+  // Make sure that there is a string literal as the annotation's single
+  // argument.
+  StringRef Str;
+  if (!S.checkStringLiteralArgumentAttr(AL, 0, Str))
+    return;
+
+  D->addAttr(::new (S.Context) SwiftAttrAttr(S.Context, AL, Str));
+}
+
 static void handleSwiftBridge(Sema &S, Decl *D, const ParsedAttr &AL) {
   // Make sure that there is a string literal as the annotation's single
   // argument.
@@ -7941,6 +7951,9 @@
     break;
 
   // Swift attributes.
+  case ParsedAttr::AT_SwiftAttr:
+    handleSwiftAttrAttr(S, D, AL);
+    break;
   case ParsedAttr::AT_SwiftBridge:
     handleSwiftBridge(S, D, AL);
     break;
diff --git a/clang/test/AST/attr-swift_attr.m b/clang/test/AST/attr-swift_attr.m
new file mode 100644
--- /dev/null
+++ b/clang/test/AST/attr-swift_attr.m
@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -fsyntax-only -ast-dump %s | FileCheck %s
+
+__attribute__((swift_attr("@actor")))
+@interface View
+@end
+
+// CHECK: InterfaceDecl {{.*}} View
+// CHECK-NEXT: SwiftAttrAttr {{.*}} "@actor"
diff --git a/clang/test/SemaObjC/validate-attr-swift_attr.m b/clang/test/SemaObjC/validate-attr-swift_attr.m
new file mode 100644
--- /dev/null
+++ b/clang/test/SemaObjC/validate-attr-swift_attr.m
@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -verify -fsyntax-only %s
+
+// expected-error@+1 {{'swift_attr' attribute takes one argument}}
+__attribute__((swift_attr))
+@interface I
+@end
+
+// expected-error@+1 {{'swift_attr' attribute requires a string}}
+__attribute__((swift_attr(1)))
+@interface J
+@end