Fix coredump for when an ID is used illegally outside a record


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7411 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/TableGen/FileParser.y b/utils/TableGen/FileParser.y
index f8fa16d..55938f4 100644
--- a/utils/TableGen/FileParser.y
+++ b/utils/TableGen/FileParser.y
@@ -245,6 +245,10 @@
     $$ = Init;
     delete $2;
   } | ID {
+    if (CurRec == 0) {
+      err() << "Def/Class name '" << *$1 << "' not allowed here!\n";
+      abort();
+    }
     if (const RecordVal *RV = CurRec->getValue(*$1)) {
       $$ = new VarInit(*$1, RV->getType());
     } else if (Record *D = Records.getDef(*$1)) {