diff --git a/include/llvm/ADT/ArrayRef.h b/include/llvm/ADT/ArrayRef.h
index 397e2ee1f6e..c8242f50282 100644
--- a/include/llvm/ADT/ArrayRef.h
+++ b/include/llvm/ADT/ArrayRef.h
@@ -286,6 +286,11 @@ namespace llvm {
       return MutableArrayRef<T>(data()+N, M);
     }
 
+    MutableArrayRef<T> drop_back(unsigned N) const {
+      assert(this->size() >= N && "Dropping more elements than exist");
+      return slice(0, this->size() - N);
+    }
+
     /// @}
     /// @name Operator Overloads
     /// @{
diff --git a/include/llvm/LibDriver/LibDriver.h b/include/llvm/LibDriver/LibDriver.h
index 99c783c95cb..aaaa7b7d21c 100644
--- a/include/llvm/LibDriver/LibDriver.h
+++ b/include/llvm/LibDriver/LibDriver.h
@@ -15,9 +15,11 @@
 #ifndef LLVM_LIBDRIVER_LIBDRIVER_H
 #define LLVM_LIBDRIVER_LIBDRIVER_H
 
+#include "llvm/ADT/ArrayRef.h"
+
 namespace llvm {
 
-int libDriverMain(int argc, const char **argv);
+int libDriverMain(llvm::ArrayRef<const char*> ARgs);
 
 }
 
diff --git a/lib/LibDriver/LibDriver.cpp b/lib/LibDriver/LibDriver.cpp
index 0b7c4756d0a..e441fe84c39 100644
--- a/lib/LibDriver/LibDriver.cpp
+++ b/lib/LibDriver/LibDriver.cpp
@@ -103,19 +103,18 @@ static Optional<std::string> findInputFile(StringRef File,
   return Optional<std::string>();
 }
 
-int llvm::libDriverMain(int Argc, const char **Argv) {
-  SmallVector<const char *, 20> NewArgv(Argv, Argv + Argc);
+int llvm::libDriverMain(llvm::ArrayRef<const char*> ArgsArr) {
+  SmallVector<const char *, 20> NewArgs(ArgsArr.begin(), ArgsArr.end());
   BumpPtrAllocator Alloc;
   BumpPtrStringSaver Saver(Alloc);
-  cl::ExpandResponseFiles(Saver, cl::TokenizeWindowsCommandLine, NewArgv);
-  Argv = &NewArgv[0];
-  Argc = static_cast<int>(NewArgv.size());
+  cl::ExpandResponseFiles(Saver, cl::TokenizeWindowsCommandLine, NewArgs);
+  ArgsArr = NewArgs;
 
   LibOptTable Table;
   unsigned MissingIndex;
   unsigned MissingCount;
-  std::unique_ptr<llvm::opt::InputArgList> Args(Table.ParseArgs(
-      makeArrayRef(Argv, Argc).slice(1), MissingIndex, MissingCount));
+  std::unique_ptr<llvm::opt::InputArgList> Args(
+      Table.ParseArgs(ArgsArr.slice(1), MissingIndex, MissingCount));
   if (MissingCount) {
     llvm::errs() << "missing arg value for \""
                  << Args->getArgString(MissingIndex)
@@ -148,7 +147,7 @@ int llvm::libDriverMain(int Argc, const char **Argv) {
       getOutputPath(Args.get()), Members, /*WriteSymtab=*/true);
   if (Result.second) {
     if (Result.first.empty())
-      Result.first = Argv[0];
+      Result.first = ArgsArr[0];
     llvm::errs() << Result.first << ": " << Result.second.message() << "\n";
     return 1;
   }
diff --git a/tools/llvm-ar/llvm-ar.cpp b/tools/llvm-ar/llvm-ar.cpp
index 6782b9c126a..0fd2df4f5aa 100644
--- a/tools/llvm-ar/llvm-ar.cpp
+++ b/tools/llvm-ar/llvm-ar.cpp
@@ -724,7 +724,7 @@ int main(int argc, char **argv) {
   StringRef Stem = sys::path::stem(ToolName);
   if (Stem.find("ranlib") == StringRef::npos &&
       Stem.find("lib") != StringRef::npos)
-    return libDriverMain(argc, const_cast<const char **>(argv));
+    return libDriverMain(makeArrayRef(argv, argc));
 
   // Have the command line options parsed and handle things
   // like --help and --version.