Implement Paste

Add a paste operator '#' to take two identifier-like strings and joint
them.  Internally paste gets represented as a !strconcat() with any
necessary casts to string added.

This will be used to implement basic for loop functionality as in:

for i = [0, 1, 2, 3, 4, 5, 6, 7] {
  def R#i : Register<...>
}

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142525 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/TableGen/TGLexer.h b/lib/TableGen/TGLexer.h
index 24f8ea4..0246ab6 100644
--- a/lib/TableGen/TGLexer.h
+++ b/lib/TableGen/TGLexer.h
@@ -39,7 +39,8 @@
     colon, semi,        // : ;
     comma, period,      // , .
     equal, question,    // = ?
-    
+    paste,              // #
+
     // Keywords.
     Bit, Bits, Class, Code, Dag, Def, Defm, Field, In, Int, Let, List,
     MultiClass, String,