uselistorder: Update for LLVM API change in r234959

Now that `addBitcodeWriterPass()` requires an explicit bit to preserve
use-list order, send it in from `clang`.  It looks like I'll be able to
push this up to the `-cc1` options.

llvm-svn: 234960

clang/lib/CodeGen/BackendUtil.cpp

@@ -24,6 +24,7 @@
 #include "llvm/IR/IRPrintingPasses.h"
 #include "llvm/IR/LegacyPassManager.h"
 #include "llvm/IR/Module.h"
+#include "llvm/IR/UseListOrder.h"
 #include "llvm/IR/Verifier.h"
 #include "llvm/MC/SubtargetFeature.h"
 #include "llvm/Support/CommandLine.h"
@@ -601,7 +602,8 @@ void EmitAssemblyHelper::EmitAssembly(BackendAction Action,
     break;
 
   case Backend_EmitBC:
-    getPerModulePasses()->add(createBitcodeWriterPass(*OS));
+    getPerModulePasses()->add(
+        createBitcodeWriterPass(*OS, shouldPreserveBitcodeUseListOrder()));
     break;
 
   case Backend_EmitLL: