--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/unittests/Support/ThreadPool.cpp	Tue Jan 26 22:53:40 2016 +0900
@@ -0,0 +1,168 @@
+//========- unittests/Support/ThreadPools.cpp - ThreadPools.h tests --========//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/ThreadPool.h"
+
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Triple.h"
+#include "llvm/Support/Host.h"
+#include "llvm/Support/TargetSelect.h"
+
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+// Fixture for the unittests, allowing to *temporarily* disable the unittests
+// on a particular platform
+class ThreadPoolTest : public testing::Test {
+  Triple Host;
+  SmallVector<Triple::ArchType, 4> UnsupportedArchs;
+  SmallVector<Triple::OSType, 4> UnsupportedOSs;
+  SmallVector<Triple::EnvironmentType, 1> UnsupportedEnvironments;
+protected:
+  // This is intended for platform as a temporary "XFAIL"
+  bool isUnsupportedOSOrEnvironment() {
+    Triple Host(Triple::normalize(sys::getProcessTriple()));
+
+    if (std::find(UnsupportedEnvironments.begin(), UnsupportedEnvironments.end(),
+                  Host.getEnvironment()) != UnsupportedEnvironments.end())
+      return true;
+
+    if (std::find(UnsupportedOSs.begin(), UnsupportedOSs.end(), Host.getOS())
+        != UnsupportedOSs.end())
+      return true;
+
+    if (std::find(UnsupportedArchs.begin(), UnsupportedArchs.end(), Host.getArch())
+        != UnsupportedArchs.end())
+      return true;
+
+    return false;
+  }
+
+  ThreadPoolTest() {
+    // Add unsupported configuration here, example:
+    //   UnsupportedArchs.push_back(Triple::x86_64);
+
+    // See https://llvm.org/bugs/show_bug.cgi?id=25829
+    UnsupportedArchs.push_back(Triple::ppc64le);
+    UnsupportedArchs.push_back(Triple::ppc64);
+  }
+
+  /// Make sure this thread not progress faster than the main thread.
+  void waitForMainThread() {
+    std::unique_lock<std::mutex> LockGuard(WaitMainThreadMutex);
+    WaitMainThread.wait(LockGuard, [&] { return MainThreadReady; });
+  }
+
+  /// Set the readiness of the main thread.
+  void setMainThreadReady() {
+    {
+      std::unique_lock<std::mutex> LockGuard(WaitMainThreadMutex);
+      MainThreadReady = true;
+    }
+    WaitMainThread.notify_all();
+  }
+
+  void SetUp() override { MainThreadReady = false; }
+
+  std::condition_variable WaitMainThread;
+  std::mutex WaitMainThreadMutex;
+  bool MainThreadReady;
+
+};
+
+#define CHECK_UNSUPPORTED() \
+  do { \
+    if (isUnsupportedOSOrEnvironment()) \
+      return; \
+  } while (0); \
+
+TEST_F(ThreadPoolTest, AsyncBarrier) {
+  CHECK_UNSUPPORTED();
+  // test that async & barrier work together properly.
+
+  std::atomic_int checked_in{0};
+
+  ThreadPool Pool;
+  for (size_t i = 0; i < 5; ++i) {
+    Pool.async([this, &checked_in, i] {
+      waitForMainThread();
+      ++checked_in;
+    });
+  }
+  ASSERT_EQ(0, checked_in);
+  setMainThreadReady();
+  Pool.wait();
+  ASSERT_EQ(5, checked_in);
+}
+
+static void TestFunc(std::atomic_int &checked_in, int i) { checked_in += i; }
+
+TEST_F(ThreadPoolTest, AsyncBarrierArgs) {
+  CHECK_UNSUPPORTED();
+  // Test that async works with a function requiring multiple parameters.
+  std::atomic_int checked_in{0};
+
+  ThreadPool Pool;
+  for (size_t i = 0; i < 5; ++i) {
+    Pool.async(TestFunc, std::ref(checked_in), i);
+  }
+  Pool.wait();
+  ASSERT_EQ(10, checked_in);
+}
+
+TEST_F(ThreadPoolTest, Async) {
+  CHECK_UNSUPPORTED();
+  ThreadPool Pool;
+  std::atomic_int i{0};
+  Pool.async([this, &i] {
+    waitForMainThread();
+    ++i;
+  });
+  Pool.async([&i] { ++i; });
+  ASSERT_NE(2, i.load());
+  setMainThreadReady();
+  Pool.wait();
+  ASSERT_EQ(2, i.load());
+}
+
+TEST_F(ThreadPoolTest, GetFuture) {
+  CHECK_UNSUPPORTED();
+  ThreadPool Pool;
+  std::atomic_int i{0};
+  Pool.async([this, &i] {
+    waitForMainThread();
+    ++i;
+  });
+  // Force the future using get()
+  Pool.async([&i] { ++i; }).get();
+  ASSERT_NE(2, i.load());
+  setMainThreadReady();
+  Pool.wait();
+  ASSERT_EQ(2, i.load());
+}
+
+TEST_F(ThreadPoolTest, PoolDestruction) {
+  CHECK_UNSUPPORTED();
+  // Test that we are waiting on destruction
+  std::atomic_int checked_in{0};
+  {
+    ThreadPool Pool;
+    for (size_t i = 0; i < 5; ++i) {
+      Pool.async([this, &checked_in, i] {
+        waitForMainThread();
+        ++checked_in;
+      });
+    }
+    ASSERT_EQ(0, checked_in);
+    setMainThreadReady();
+  }
+  ASSERT_EQ(5, checked_in);
+}