Frontend: Add a more explicit -backend-option flag for passing backend command
line options, instead of leveraging the blanket -mllvm option.
 - This allows using the frontend itself without requiring the backend have
   those options available (i.e., if the target wasn't built).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@128087 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/BackendUtil.cpp b/lib/CodeGen/BackendUtil.cpp
index 9897b1b..ce64dc7 100644
--- a/lib/CodeGen/BackendUtil.cpp
+++ b/lib/CodeGen/BackendUtil.cpp
@@ -248,6 +248,8 @@
   }
   if (llvm::TimePassesIsEnabled)
     BackendArgs.push_back("-time-passes");
+  for (unsigned i = 0, e = CodeGenOpts.BackendOptions.size(); i != e; ++i)
+    BackendArgs.push_back(CodeGenOpts.BackendOptions[i].c_str());
   BackendArgs.push_back(0);
   llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
                                     const_cast<char **>(&BackendArgs[0]));