Give internal classes hidden visibility.

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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190534 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CriticalAntiDepBreaker.h b/lib/CodeGen/CriticalAntiDepBreaker.h
index 565d20b..ef4059e 100644
--- a/lib/CodeGen/CriticalAntiDepBreaker.h
+++ b/lib/CodeGen/CriticalAntiDepBreaker.h
@@ -31,7 +31,7 @@
 class TargetInstrInfo;
 class TargetRegisterInfo;
 
-  class CriticalAntiDepBreaker : public AntiDepBreaker {
+  class LLVM_LIBRARY_VISIBILITY CriticalAntiDepBreaker : public AntiDepBreaker {
     MachineFunction& MF;
     MachineRegisterInfo &MRI;
     const TargetInstrInfo *TII;