diff --git a/lib/System/ThreadLocal.cpp b/lib/System/ThreadLocal.cpp
new file mode 100644
index 0000000..1c07036
--- /dev/null
+++ b/lib/System/ThreadLocal.cpp
@@ -0,0 +1,77 @@
+//===- ThreadLocal.cpp - Thread Local Data ----------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the llvm::sys::ThreadLocal class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Config/config.h"
+#include "llvm/System/ThreadLocal.h"
+
+//===----------------------------------------------------------------------===//
+//=== WARNING: Implementation here must contain only TRULY operating system
+//===          independent code.
+//===----------------------------------------------------------------------===//
+
+#if !defined(ENABLE_THREADS) || ENABLE_THREADS == 0
+// Define all methods as no-ops if threading is explicitly disabled
+namespace llvm {
+using namespace sys;
+ThreadLocalImpl::ThreadLocalImpl() { }
+ThreadLocalImpl::~ThreadLocalImpl() { }
+void ThreadLocalImpl::setInstance(void* d) { data = d; }
+void* ThreadLocalImpl::getInstance() { return data; }
+}
+#else
+
+#if defined(HAVE_PTHREAD_H) && defined(HAVE_PTHREAD_MUTEX_LOCK)
+
+#include <cassert>
+#include <pthread.h>
+#include <stdlib.h>
+
+namespace llvm {
+using namespace sys;
+
+ThreadLocalImpl::ThreadLocalImpl() : data(0) {
+  pthread_key_t* key = new pthread_key_t;
+  int errorcode = pthread_key_create(key, NULL);
+  assert(errorcode == 0);
+  data = key;
+}
+
+ThreadLocalImpl::~ThreadLocalImpl() {
+  pthread_key_t* key = static_cast<pthread_key_t*>(data);
+  int errorcode = pthread_key_delete(*key);
+  assert(errorcode = 0);
+  delete key;
+}
+
+void ThreadLocalImpl::setInstance(void* d) {
+  pthread_key_t* key = static_cast<pthread_key_t*>(data);
+  int errorcode = pthread_setspecific(*key, d);
+  assert(errorcode == 0);
+}
+
+void* ThreadLocalImpl::getInstance() {
+  pthread_key_t* key = static_cast<pthread_key_t*>(data);
+  return pthread_getspecific(*key);
+}
+
+}
+
+#elif defined(LLVM_ON_UNIX)
+#include "Unix/ThreadLocal.inc"
+#elif defined( LLVM_ON_WIN32)
+#include "Win32/ThreadLocal.inc"
+#else
+#warning Neither LLVM_ON_UNIX nor LLVM_ON_WIN32 was set in System/ThreadLocal.cpp
+#endif
+#endif
+