Do not crash when dumping the objc_bridge_related attribute when its optional arguments are not supplied.

Patch thanks to Joe Ranieri!

llvm-svn: 254303

clang/include/clang/Basic/Attr.td

@@ -1087,8 +1087,8 @@ def ObjCBridgeRelated : InheritableAttr {
   let Spellings = [GNU<"objc_bridge_related">];
   let Subjects = SubjectList<[Record], ErrorDiag>;
   let Args = [IdentifierArgument<"RelatedClass">,
-          IdentifierArgument<"ClassMethod">,
-          IdentifierArgument<"InstanceMethod">];
+          IdentifierArgument<"ClassMethod", 1>,
+          IdentifierArgument<"InstanceMethod", 1>];
   let HasCustomParsing = 1;
   let Documentation = [Undocumented];
 }

clang/test/Misc/ast-dump-attr.cpp

@@ -150,3 +150,7 @@ void f() {
   // CHECK: DeprecatedAttr
 }
 }
+
+struct __attribute__((objc_bridge_related(NSParagraphStyle,,))) TestBridgedRef;
+// CHECK: CXXRecordDecl{{.*}} struct TestBridgedRef
+// CHECK-NEXT: ObjCBridgeRelatedAttr{{.*}} NSParagraphStyle

clang/utils/TableGen/ClangAttrEmitter.cpp

@@ -279,6 +279,8 @@ namespace {
         OS << "    OS << \" \";\n";
         OS << "    dumpBareDeclRef(SA->get" << getUpperName() << "());\n"; 
       } else if (type == "IdentifierInfo *") {
+        if (isOptional())
+          OS << "    if (SA->get" << getUpperName() << "())\n  ";
         OS << "    OS << \" \" << SA->get" << getUpperName()
            << "()->getName();\n";
       } else if (type == "TypeSourceInfo *") {