diff --git a/llvm/lib/Fuzzer/FuzzerIO.cpp b/llvm/lib/Fuzzer/FuzzerIO.cpp
index 6cc8a8e0..5d4d415 100644
--- a/llvm/lib/Fuzzer/FuzzerIO.cpp
+++ b/llvm/lib/Fuzzer/FuzzerIO.cpp
@@ -11,26 +11,17 @@
 #include "FuzzerIO.h"
 #include "FuzzerDefs.h"
 #include "FuzzerExtFunctions.h"
-#include <iterator>
+#include <algorithm>
+#include <cstdarg>
 #include <fstream>
-#include <dirent.h>
+#include <iterator>
 #include <sys/types.h>
 #include <sys/stat.h>
-#include <unistd.h>
-#include <cstdarg>
-#include <cstdio>
 
 namespace fuzzer {
 
 static FILE *OutputFile = stderr;
 
-bool IsFile(const std::string &Path) {
-  struct stat St;
-  if (stat(Path.c_str(), &St))
-    return false;
-  return S_ISREG(St.st_mode);
-}
-
 long GetEpoch(const std::string &Path) {
   struct stat St;
   if (stat(Path.c_str(), &St))
@@ -38,29 +29,6 @@
   return St.st_mtime;
 }
 
-static void ListFilesInDirRecursive(const std::string &Dir, long *Epoch,
-                                    std::vector<std::string> *V, bool TopDir) {
-  auto E = GetEpoch(Dir);
-  if (Epoch)
-    if (E && *Epoch >= E) return;
-
-  DIR *D = opendir(Dir.c_str());
-  if (!D) {
-    Printf("No such directory: %s; exiting\n", Dir.c_str());
-    exit(1);
-  }
-  while (auto E = readdir(D)) {
-    std::string Path = DirPlusFile(Dir, E->d_name);
-    if (E->d_type == DT_REG || E->d_type == DT_LNK)
-      V->push_back(Path);
-    else if (E->d_type == DT_DIR && *E->d_name != '.')
-      ListFilesInDirRecursive(Path, Epoch, V, false);
-  }
-  closedir(D);
-  if (Epoch && TopDir)
-    *Epoch = E;
-}
-
 Unit FileToVector(const std::string &Path, size_t MaxSize, bool ExitOnError) {
   std::ifstream T(Path);
   if (ExitOnError && !T) {
@@ -79,10 +47,6 @@
   return Res;
 }
 
-void DeleteFile(const std::string &Path) {
-  unlink(Path.c_str());
-}
-
 std::string FileToString(const std::string &Path) {
   std::ifstream T(Path);
   return std::string((std::istreambuf_iterator<char>(T)),
@@ -121,23 +85,25 @@
 
 std::string DirPlusFile(const std::string &DirPath,
                         const std::string &FileName) {
-  return DirPath + "/" + FileName;
+  return DirPath + GetSeparator() + FileName;
 }
 
 void DupAndCloseStderr() {
-  int OutputFd = dup(2);
+  int OutputFd = DuplicateFile(2);
   if (OutputFd > 0) {
-    FILE *NewOutputFile = fdopen(OutputFd, "w");
+    FILE *NewOutputFile = OpenFile(OutputFd, "w");
     if (NewOutputFile) {
       OutputFile = NewOutputFile;
       if (EF->__sanitizer_set_report_fd)
         EF->__sanitizer_set_report_fd(reinterpret_cast<void *>(OutputFd));
-      close(2);
+      CloseFile(2);
     }
   }
 }
 
-void CloseStdout() { close(1); }
+void CloseStdout() {
+  CloseFile(1);
+}
 
 void Printf(const char *Fmt, ...) {
   va_list ap;