Add -emit-llvm-only option (generate LLVM IR & run passes, but discard
output).
 - For timing IRgen phase.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@65580 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Driver/ASTConsumers.h b/Driver/ASTConsumers.h
index 34c9fb2..670f8dc 100644
--- a/Driver/ASTConsumers.h
+++ b/Driver/ASTConsumers.h
@@ -48,7 +48,8 @@
 enum BackendAction {
   Backend_EmitAssembly,
   Backend_EmitBC,
-  Backend_EmitLL
+  Backend_EmitLL,
+  Backend_EmitNothing
 };
 ASTConsumer *CreateBackendConsumer(BackendAction Action,
                                    Diagnostic &Diags,