Give internal classes hidden visibility.

Worth 100k on a linux/x86_64 Release+Asserts clang.

llvm-svn: 190534
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
index 6463eca..ec640bc 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
@@ -79,7 +79,7 @@
 /// SelectionDAGBuilder - This is the common target-independent lowering
 /// implementation that is parameterized by a TargetLowering object.
 ///
-class SelectionDAGBuilder {
+class LLVM_LIBRARY_VISIBILITY SelectionDAGBuilder {
   /// CurInst - The current instruction being visited
   const Instruction *CurInst;