[OPENMP] Add support for OMP5 requires directive + unified_address clause

Add support for OMP5.0 requires directive and unified_address clause.
Patches to follow will include support for additional clauses.

Differential Revision: https://reviews.llvm.org/D52359

llvm-svn: 343063
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index c143cb0..2e0d424 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -11721,6 +11721,9 @@
   case OMPC_nogroup:
     C = new (Context) OMPNogroupClause();
     break;
+  case OMPC_unified_address:
+    C = new (Context) OMPUnifiedAddressClause();
+    break;
   case OMPC_private:
     C = OMPPrivateClause::CreateEmpty(Context, Record.readInt());
     break;
@@ -11949,6 +11952,8 @@
 
 void OMPClauseReader::VisitOMPNogroupClause(OMPNogroupClause *) {}
 
+void OMPClauseReader::VisitOMPUnifiedAddressClause(OMPUnifiedAddressClause *) {}
+
 void OMPClauseReader::VisitOMPPrivateClause(OMPPrivateClause *C) {
   C->setLParenLoc(Record.readSourceLocation());
   unsigned NumVars = C->varlist_size();