[OPENMP 5.0]Initial support for 'allocator' clause.

Added parsing/sema analysis/serialization/deserialization for the
'allocator' clause of the 'allocate' directive.

llvm-svn: 355952
diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp
index cfcd81b..37173e8 100644
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -1747,9 +1747,13 @@
 
 void ASTDeclWriter::VisitOMPAllocateDecl(OMPAllocateDecl *D) {
   Record.push_back(D->varlist_size());
+  Record.push_back(D->clauselist_size());
   VisitDecl(D);
   for (auto *I : D->varlists())
     Record.AddStmt(I);
+  OMPClauseWriter ClauseWriter(Record);
+  for (OMPClause *C : D->clauselists())
+    ClauseWriter.writeClause(C);
   Code = serialization::DECL_OMP_ALLOCATE;
 }