[OpenMP] Parsing and sema support for target update directive

Summary:
This patch is to add parsing and sema support for `target update` directive. Support for the `to` and `from` clauses will be added by a different patch.  This patch also adds support for other clauses that are already implemented upstream and apply to `target update`, e.g. `device` and `if`.

This patch is based on the original post by Kelvin Li.

Reviewers: hfinkel, carlo.bertolli, kkwli0, arpith-jacob, ABataev

Subscribers: caomhin, cfe-commits

Differential Revision: http://reviews.llvm.org/D15944

llvm-svn: 270878

1 files changed, 6 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGStmtOpenMP.cpp b/clang/lib/CodeGen/CGStmtOpenMP.cpp
index b3ff09b143b..34fa2602d5c 100644
--- a/clang/lib/CodeGen/CGStmtOpenMP.cpp
+++ b/clang/lib/CodeGen/CGStmtOpenMP.cpp
@@ -3544,3 +3544,9 @@ void CodeGenFunction::EmitOMPTaskLoopSimdDirective(
     const OMPTaskLoopSimdDirective &S) {
   EmitOMPTaskLoopBasedDirective(S);
 }
+
+// Generate the instructions for '#pragma omp target update' directive.
+void CodeGenFunction::EmitOMPTargetUpdateDirective(
+    const OMPTargetUpdateDirective &S) {
+  // TODO: codegen for target update
+}