Added a new attribute, objc_root_class, which informs the compiler when a root class is intentionally declared.

The warning this inhibits, -Wobjc-root-class, is opt-in for now. However, all clang unit tests that would trigger
the warning have been updated to use -Wno-objc-root-class. <rdar://problem/7446698>

llvm-svn: 154187

1 files changed, 19 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index 081c93f8c20..77809e153f1 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -1593,6 +1593,22 @@ static void handleArcWeakrefUnavailableAttr(Sema &S, Decl *D,
                                           Attr.getRange(), S.Context));
 }
 
+static void handleObjCRootClassAttr(Sema &S, Decl *D, 
+                                    const AttributeList &Attr) {
+  if (!isa<ObjCInterfaceDecl>(D)) {
+    S.Diag(Attr.getLoc(), diag::err_attribute_requires_objc_interface);
+    return;
+  }
+  
+  unsigned NumArgs = Attr.getNumArgs();
+  if (NumArgs > 0) {
+    S.Diag(Attr.getLoc(), diag::err_attribute_too_many_arguments) << 0;
+    return;
+  }
+  
+  D->addAttr(::new (S.Context) ObjCRootClassAttr(Attr.getRange(), S.Context));
+}
+
 static void handleObjCRequiresPropertyDefsAttr(Sema &S, Decl *D, 
                                             const AttributeList &Attr) {
   if (!isa<ObjCInterfaceDecl>(D)) {
@@ -3658,6 +3674,9 @@ static void ProcessInheritableDeclAttr(Sema &S, Scope *scope, Decl *D,
   case AttributeList::AT_objc_arc_weak_reference_unavailable: 
     handleArcWeakrefUnavailableAttr (S, D, Attr); 
     break;
+  case AttributeList::AT_objc_root_class:
+    handleObjCRootClassAttr(S, D, Attr);
+    break;
   case AttributeList::AT_objc_requires_property_definitions: 
     handleObjCRequiresPropertyDefsAttr (S, D, Attr); 
     break;