Run the ObjCARCContract pass for LTO. <rdar://problem/13538084>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178385 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/lto/LTOCodeGenerator.cpp b/tools/lto/LTOCodeGenerator.cpp
index cf7ffe2..e7c83f9 100644
--- a/tools/lto/LTOCodeGenerator.cpp
+++ b/tools/lto/LTOCodeGenerator.cpp
@@ -44,6 +44,7 @@
 #include "llvm/Target/TargetRegisterInfo.h"
 #include "llvm/Transforms/IPO.h"
 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
+#include "llvm/Transforms/ObjCARC.h"
 using namespace llvm;
 
 static cl::opt<bool>
@@ -397,6 +398,10 @@
 
   formatted_raw_ostream Out(out);
 
+  // If the bitcode files contain ARC code and were compiled with optimization,
+  // the ObjCARCContractPass must be run, so do it unconditionally here.
+  codeGenPasses.add(createObjCARCContractPass());
+
   if (_target->addPassesToEmitFile(codeGenPasses, Out,
                                    TargetMachine::CGFT_ObjectFile)) {
     errMsg = "target file type not supported";