avoid accessing off the end of identifiers.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@42841 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Basic/IdentifierTable.cpp b/Basic/IdentifierTable.cpp
index 51abcd2..7c26816 100644
--- a/Basic/IdentifierTable.cpp
+++ b/Basic/IdentifierTable.cpp
@@ -157,6 +157,7 @@
     return memcmp(Name, #NAME, LEN) ? tok::pp_not_keyword : tok::pp_ ## NAME
     
   unsigned Len = getLength();
+  if (Len < 2) return tok::pp_not_keyword;
   const char *Name = getName();
   switch (HASH(Len, Name[0], Name[2])) {
   default: return tok::pp_not_keyword;