sys: work around a threading-related Visual Studio bug.

When a thread is destroyed during the atexit() callback cleanup, it cannot
be joined and sits there doing nothing if the CRT is Visual Studio 2012 or
2013. Microsoft has stated that they would not be backporting the fix from
Visual Studio 2015. As a workaround we call ExitThread() forcibly after
the thread exits.

src/sys/threadbase.h

@@ -26,16 +26,17 @@
 #   include <condition_variable>
 #elif defined HAVE_PTHREAD_H
 #   include <pthread.h>
-#elif defined _XBOX
-#   include <xtl.h>
-#   undef near /* Fuck Microsoft */
-#   undef far /* Fuck Microsoft again */
-#elif defined _WIN32
+#else
+#   error No threading support yet :(
+#endif
+
+/* XXX: workaround for a bug in Visual Studio 2012 and 2013!
+ * https://connect.microsoft.com/VisualStudio/feedback/details/747145 */
+#if defined(_MSC_VER) && (_MSC_VER < 1900)
+#   define LOL_VISUAL_STUDIO_BUG_747145_WORKAROUND 1
 #   include <windows.h>
 #   undef near /* Fuck Microsoft */
 #   undef far /* Fuck Microsoft again */
-#else
-#   error No threading support yet :(
 #endif
 
 namespace lol
@@ -53,8 +54,6 @@ public:
         /* Nothing */
 #elif defined HAVE_PTHREAD_H
         pthread_mutex_init(&m_mutex, nullptr);
-#elif defined _WIN32
-        InitializeCriticalSection(&m_mutex);
 #endif
     }
 
@@ -67,8 +66,6 @@ public:
         /* Nothing */
 #elif defined HAVE_PTHREAD_H
         pthread_mutex_destroy(&m_mutex);
-#elif defined _WIN32
-        DeleteCriticalSection(&m_mutex);
 #endif
     }
 
@@ -81,8 +78,6 @@ public:
         m_mutex.lock();
 #elif defined HAVE_PTHREAD_H
         pthread_mutex_lock(&m_mutex);
-#elif defined _WIN32
-        EnterCriticalSection(&m_mutex);
 #endif
     }
 
@@ -95,8 +90,6 @@ public:
         return m_mutex.try_lock();
 #elif defined HAVE_PTHREAD_H
         return !pthread_mutex_trylock(&m_mutex);
-#elif defined _WIN32
-        return !!TryEnterCriticalSection(&m_mutex);
 #endif
     }
 
@@ -109,8 +102,6 @@ public:
         m_mutex.unlock();
 #elif defined HAVE_PTHREAD_H
         pthread_mutex_unlock(&m_mutex);
-#elif defined _WIN32
-        LeaveCriticalSection(&m_mutex);
 #endif
     }
 
@@ -122,8 +113,6 @@ private:
     std::mutex m_mutex;
 #elif defined HAVE_PTHREAD_H
     pthread_mutex_t m_mutex;
-#elif defined _WIN32
-    CRITICAL_SECTION m_mutex;
 #endif
 };
 
@@ -144,10 +133,6 @@ public:
         pthread_mutex_init(&m_mutex, nullptr);
         pthread_cond_init(&m_empty_cond, nullptr);
         pthread_cond_init(&m_full_cond, nullptr);
-#elif defined _WIN32
-        m_empty_sem = CreateSemaphore(nullptr, CAPACITY, CAPACITY, nullptr);
-        m_full_sem = CreateSemaphore(nullptr, 0, CAPACITY, nullptr);
-        InitializeCriticalSection(&m_mutex);
 #endif
     }
 
@@ -161,10 +146,6 @@ public:
         pthread_cond_destroy(&m_empty_cond);
         pthread_cond_destroy(&m_full_cond);
         pthread_mutex_destroy(&m_mutex);
-#elif defined _WIN32
-        CloseHandle(m_empty_sem);
-        CloseHandle(m_full_sem);
-        DeleteCriticalSection(&m_mutex);
 #endif
     }
 
@@ -184,9 +165,6 @@ public:
         while (m_count == CAPACITY)
             pthread_cond_wait(&m_full_cond, &m_mutex);
         m_pushers--;
-#elif defined _WIN32
-        WaitForSingleObject(m_empty_sem, INFINITE);
-        EnterCriticalSection(&m_mutex);
 #endif
 
         do_push(value); /* Push value */
@@ -202,9 +180,6 @@ public:
         if (m_poppers)
             pthread_cond_signal(&m_empty_cond);
         pthread_mutex_unlock(&m_mutex);
-#elif defined _WIN32
-        LeaveCriticalSection(&m_mutex);
-        ReleaseSemaphore(m_full_sem, 1, nullptr);
 #endif
     }
 
@@ -236,11 +211,6 @@ public:
             pthread_mutex_unlock(&m_mutex);
             return false;
         }
-#elif defined _WIN32
-        DWORD status = WaitForSingleObject(m_empty_sem, 0);
-        if (status == WAIT_TIMEOUT)
-            return false;
-        EnterCriticalSection(&m_mutex);
 #endif
 
         do_push(value); /* Push value */
@@ -256,9 +226,6 @@ public:
         if (m_poppers)
             pthread_cond_signal(&m_empty_cond);
         pthread_mutex_unlock(&m_mutex);
-#elif defined _WIN32
-        LeaveCriticalSection(&m_mutex);
-        ReleaseSemaphore(m_full_sem, 1, nullptr);
 #endif
 
         return true;
@@ -282,9 +249,6 @@ public:
         while (m_count == 0)
             pthread_cond_wait(&m_empty_cond, &m_mutex);
         m_poppers--;
-#elif defined _WIN32
-        WaitForSingleObject(m_full_sem, INFINITE);
-        EnterCriticalSection(&m_mutex);
 #endif
 
         T ret = do_pop(); /* Pop value */
@@ -333,11 +297,6 @@ public:
             pthread_mutex_unlock(&m_mutex);
             return false;
         }
-#elif defined _WIN32
-        DWORD status = WaitForSingleObject(m_full_sem, 0);
-        if (status == WAIT_TIMEOUT)
-            return false;
-        EnterCriticalSection(&m_mutex);
 #endif
 
         ret = do_pop(); /* Pop value */
@@ -391,9 +350,6 @@ private:
     size_t m_poppers, m_pushers;
     pthread_mutex_t m_mutex;
     pthread_cond_t m_empty_cond, m_full_cond;
-#elif defined _WIN32
-    HANDLE m_empty_sem, m_full_sem;
-    CRITICAL_SECTION m_mutex;
 #endif
 };
 
@@ -417,9 +373,6 @@ public:
         pthread_attr_init(&attr);
         pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
         pthread_create(&m_thread, &attr, trampoline, this);
-#elif defined _WIN32
-        m_thread = CreateThread(nullptr, 0, (LPTHREAD_START_ROUTINE)trampoline,
-                                this, 0, &m_tid);
 #endif
     }
 
@@ -428,13 +381,13 @@ public:
 #if !defined(LOL_FEATURE_THREADS) || !LOL_FEATURE_THREADS
         /* Nothing */
 #elif LOL_FEATURE_CXX11_THREADS
-        /* FIXME: this does not work in Visual Studio 2013! */
-        //m_thread.join();
+#   if LOL_VISUAL_STUDIO_BUG_747145_WORKAROUND
         m_thread.detach();
+#   else
+        m_thread.join();
+#   endif
 #elif defined HAVE_PTHREAD_H
         pthread_join(m_thread, nullptr);
-#elif defined _WIN32
-        WaitForSingleObject(m_thread, INFINITE);
 #endif
     }
 
@@ -445,6 +398,9 @@ private:
     static void trampoline(thread_base *that)
     {
         that->m_function();
+#   if LOL_VISUAL_STUDIO_BUG_747145_WORKAROUND
+        ExitThread(0);
+#   endif
     }
 #else
     static void *trampoline(void *data)
@@ -463,9 +419,6 @@ private:
     std::thread m_thread;
 #elif defined HAVE_PTHREAD_H
     pthread_t m_thread;
-#elif defined _WIN32
-    HANDLE m_thread;
-    DWORD m_tid;
 #endif
 };