[libcxx] Add Atomic test helper and fix TSAN failures.

Summary:
This patch attempts to fix the last 3 TSAN failures on the libc++ bot (http://lab.llvm.org:8011/builders/libcxx-libcxxabi-x86_64-linux-ubuntu-tsan/builds/143). This patch also adds a `Atomic` test type that can be used where `<atomic>` cannot.

`wait.exception.pass.cpp` and `wait_for.exception.pass.cpp` were failing because the test replaced `std::terminate` with `std::exit`. `std::exit` would asynchronously run the TLS and static destructors and this would cause a race condition. See PR22606 and D8802 for more details. 

This is fixed by using `_Exit` to prevent cleanup.

`notify_all_at_thread_exit.pass.cpp` exercises the same race condition but for different reasons. I fixed this test by manually joining the thread before beginning program termination.

Reviewers: EricWF, mclow.lists

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D11046

llvm-svn: 245389

1 files changed, 132 insertions, 0 deletions

diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_terminates.sh.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_terminates.sh.cpp
new file mode 100644
index 00000000000..ed8c55d176a
--- /dev/null
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/wait_terminates.sh.cpp
@@ -0,0 +1,132 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: libcpp-has-no-threads
+
+// <condition_variable>
+
+// class condition_variable_any;
+
+// RUN: %build
+// RUN: %run 1
+// RUN: %run 2
+// RUN: %run 3
+// RUN: %run 4
+// RUN: %run 5
+// RUN: %run 6
+
+// -----------------------------------------------------------------------------
+// Overview
+//   Check that std::terminate is called if wait(...) fails to meet it's post
+//   conditions. This can happens when reacquiring the mutex throws
+//   an exception.
+//
+//  The following methods are tested within this file
+//   1.  void wait(Lock& lock);
+//   2.  void wait(Lock& lock, Pred);
+//   3.  void wait_for(Lock& lock, Duration);
+//   4.  void wait_for(Lock& lock, Duration, Pred);
+//   5.  void wait_until(Lock& lock, TimePoint);
+//   6.  void wait_until(Lock& lock, TimePoint, Pred);
+//
+// Plan
+//   1 Create a mutex type, 'ThrowingMutex', that throws when the lock is aquired
+//     for the *second* time.
+//
+//   2 Replace the terminate handler with one that exits with a '0' exit code.
+//
+//   3 Create a 'condition_variable_any' object 'cv' and a 'ThrowingMutex'
+//     object 'm' and lock 'm'.
+//
+//   4 Start a thread 'T2' that will notify 'cv' once 'm' has been unlocked.
+//
+//   5 From the main thread call the specified wait method on 'cv' with 'm'.
+//     When 'T2' notifies 'cv' and the wait method attempts to re-lock
+//    'm' an exception will be thrown from 'm.lock()'.
+//
+//   6 Check that control flow does not return from the wait method and that
+//     terminate is called (If the program exits with a 0 exit code we know
+//     that terminate has been called)
+
+
+#include <condition_variable>
+#include <thread>
+#include <chrono>
+#include <string>
+#include <cstdlib>
+#include <cassert>
+
+#include "test_atomic.h"
+
+void my_terminate() {
+  std::_Exit(0); // Use _Exit to prevent cleanup from taking place.
+}
+
+// The predicate used in the cv.wait calls.
+bool pred = false;
+bool pred_function() {
+  return pred == true;
+}
+
+class ThrowingMutex
+{
+  AtomicBool locked;
+  unsigned state = 0;
+  ThrowingMutex(const ThrowingMutex&) = delete;
+  ThrowingMutex& operator=(const ThrowingMutex&) = delete;
+public:
+  ThrowingMutex() = default;
+  ~ThrowingMutex() = default;
+
+  void lock() {
+    locked = true;
+    if (++state == 2) {
+      assert(pred); // Check that we actually waited until we were signaled.
+      throw 1;  // this throw should end up calling terminate()
+    }
+  }
+
+  void unlock() { locked = false; }
+  bool isLocked() const { return locked == true; }
+};
+
+ThrowingMutex mut;
+std::condition_variable_any cv;
+
+void signal_me() {
+  while (mut.isLocked()) {} // wait until T1 releases mut inside the cv.wait call.
+  pred = true;
+  cv.notify_one();
+}
+
+typedef std::chrono::system_clock Clock;
+typedef std::chrono::milliseconds MS;
+
+int main(int argc, char** argv) {
+  assert(argc == 2);
+  int id = std::stoi(argv[1]);
+  assert(id >= 1 && id <= 6);
+  std::set_terminate(my_terminate); // set terminate after std::stoi because it can throw.
+  MS wait(250);
+  try {
+    mut.lock();
+    assert(pred == false);
+    std::thread(signal_me).detach();
+    switch (id) {
+      case 1: cv.wait(mut); break;
+      case 2: cv.wait(mut, pred_function); break;
+      case 3: cv.wait_for(mut, wait); break;
+      case 4: cv.wait_for(mut, wait, pred_function); break;
+      case 5: cv.wait_until(mut, Clock::now() + wait); break;
+      case 6: cv.wait_until(mut, Clock::now() + wait, pred_function); break;
+      default: assert(false);
+    }
+  } catch (...) {}
+  assert(false);
+}