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/AsmPrinter/DwarfAccelTable.h b/lib/CodeGen/AsmPrinter/DwarfAccelTable.h
index 7627313..1ea0bfb 100644
--- a/lib/CodeGen/AsmPrinter/DwarfAccelTable.h
+++ b/lib/CodeGen/AsmPrinter/DwarfAccelTable.h
@@ -65,7 +65,7 @@
 class DIE;
 class DwarfUnits;
 
-class DwarfAccelTable {
+class LLVM_LIBRARY_VISIBILITY DwarfAccelTable {
 
   static uint32_t HashDJB(StringRef Str) {
     uint32_t h = 5381;