[Core] Add parallel infrastructure to lld.

Uses ConcRT and PPL on Windows.

llvm-svn: 179397
diff --git a/lld/unittests/CoreTests/ParallelTest.cpp b/lld/unittests/CoreTests/ParallelTest.cpp
new file mode 100644
index 0000000..ffa2b23
--- /dev/null
+++ b/lld/unittests/CoreTests/ParallelTest.cpp
@@ -0,0 +1,33 @@
+//===- lld/unittest/ParallelTest.cpp --------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// \brief Parallel.h unit tests.
+///
+//===----------------------------------------------------------------------===//
+
+#include "gtest/gtest.h"
+
+#include "lld/Core/Parallel.h"
+
+#include <array>
+#include <random>
+
+uint32_t array[1024 * 1024];
+
+TEST(Parallel, sort) {
+  std::mt19937 randEngine;
+  std::uniform_int_distribution<uint32_t> dist;
+
+  for (auto &i : array)
+    i = dist(randEngine);
+
+  lld::parallel_sort(std::begin(array), std::end(array));
+  ASSERT_TRUE(std::is_sorted(std::begin(array), std::end(array)));
+}