Thread safety analysis:  prevent a compiler error in cases where a
late-parsed attribute is attached to an invalid declaration.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@161997 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Parse/ParseDecl.cpp b/lib/Parse/ParseDecl.cpp
index b830d9c..a50f42b 100644
--- a/lib/Parse/ParseDecl.cpp
+++ b/lib/Parse/ParseDecl.cpp
@@ -866,7 +866,8 @@
 void Parser::ParseLexedAttributeList(LateParsedAttrList &LAs, Decl *D,
                                      bool EnterScope, bool OnDefinition) {
   for (unsigned i = 0, ni = LAs.size(); i < ni; ++i) {
-    LAs[i]->addDecl(D);
+    if (D)
+      LAs[i]->addDecl(D);
     ParseLexedAttribute(*LAs[i], EnterScope, OnDefinition);
     delete LAs[i];
   }