Add parser support for #pragma weak.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@72907 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Parse/Parser.cpp b/lib/Parse/Parser.cpp
index 1c2e8a6..a2a66f9 100644
--- a/lib/Parse/Parser.cpp
+++ b/lib/Parse/Parser.cpp
@@ -39,6 +39,10 @@
           PragmaUnusedHandler(&PP.getIdentifierTable().get("unused"), actions,
                               *this));
   PP.AddPragmaHandler(0, UnusedHandler.get());
+
+  WeakHandler.reset(new
+          PragmaWeakHandler(&PP.getIdentifierTable().get("weak"), actions));
+  PP.AddPragmaHandler(0, WeakHandler.get());
 }
 
 /// If a crash happens while the parser is active, print out a line indicating
@@ -288,6 +292,8 @@
   PackHandler.reset();
   PP.RemovePragmaHandler(0, UnusedHandler.get());
   UnusedHandler.reset();
+  PP.RemovePragmaHandler(0, WeakHandler.get());
+  WeakHandler.reset();
 }
 
 /// Initialize - Warm up the parser.