Simplify locking usage

pass references (Windows style) instead of
pointers (Posix style) as function arguments.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

src/lock.h

@@ -26,16 +26,19 @@
 
 typedef pthread_mutex_t Lock;
 typedef pthread_cond_t WaitCondition;
+typedef pthread_t ThreadHandle;
 
-#  define lock_init(x) pthread_mutex_init(x, NULL)
-#  define lock_grab(x) pthread_mutex_lock(x)
-#  define lock_release(x) pthread_mutex_unlock(x)
-#  define lock_destroy(x) pthread_mutex_destroy(x)
-#  define cond_destroy(x) pthread_cond_destroy(x)
-#  define cond_init(x) pthread_cond_init(x, NULL)
-#  define cond_signal(x) pthread_cond_signal(x)
-#  define cond_wait(x,y) pthread_cond_wait(x,y)
-#  define cond_timedwait(x,y,z) pthread_cond_timedwait(x,y,z)
+#  define lock_init(x) pthread_mutex_init(&(x), NULL)
+#  define lock_grab(x) pthread_mutex_lock(&(x))
+#  define lock_release(x) pthread_mutex_unlock(&(x))
+#  define lock_destroy(x) pthread_mutex_destroy(&(x))
+#  define cond_destroy(x) pthread_cond_destroy(&(x))
+#  define cond_init(x) pthread_cond_init(&(x), NULL)
+#  define cond_signal(x) pthread_cond_signal(&(x))
+#  define cond_wait(x,y) pthread_cond_wait(&(x),&(y))
+#  define cond_timedwait(x,y,z) pthread_cond_timedwait(&(x),&(y),z)
+#  define thread_create(x,f,id) !pthread_create(&(x),NULL,f,&(id))
+#  define thread_join(x) pthread_join(x, NULL)
 
 #else
 
@@ -50,16 +53,19 @@ typedef pthread_cond_t WaitCondition;
 // but apart from this they have the same speed performance of SRW locks.
 typedef CRITICAL_SECTION Lock;
 typedef HANDLE WaitCondition;
+typedef HANDLE ThreadHandle;
 
-#  define lock_init(x) InitializeCriticalSection(x)
-#  define lock_grab(x) EnterCriticalSection(x)
-#  define lock_release(x) LeaveCriticalSection(x)
-#  define lock_destroy(x) DeleteCriticalSection(x)
-#  define cond_init(x) { *x = CreateEvent(0, FALSE, FALSE, 0); }
-#  define cond_destroy(x) CloseHandle(*x)
-#  define cond_signal(x) SetEvent(*x)
-#  define cond_wait(x,y) { lock_release(y); WaitForSingleObject(*x, INFINITE); lock_grab(y); }
-#  define cond_timedwait(x,y,z) { lock_release(y); WaitForSingleObject(*x,z); lock_grab(y); }
+#  define lock_init(x) InitializeCriticalSection(&(x))
+#  define lock_grab(x) EnterCriticalSection(&(x))
+#  define lock_release(x) LeaveCriticalSection(&(x))
+#  define lock_destroy(x) DeleteCriticalSection(&(x))
+#  define cond_init(x) { x = CreateEvent(0, FALSE, FALSE, 0); }
+#  define cond_destroy(x) CloseHandle(x)
+#  define cond_signal(x) SetEvent(x)
+#  define cond_wait(x,y) { lock_release(y); WaitForSingleObject(x, INFINITE); lock_grab(y); }
+#  define cond_timedwait(x,y,z) { lock_release(y); WaitForSingleObject(x,z); lock_grab(y); }
+#  define thread_create(x,f,id) (x = CreateThread(NULL,0,f,&(id),0,NULL), x != NULL)
+#  define thread_join(x) { WaitForSingleObject(x, INFINITE); CloseHandle(x); }
 
 #endif
 

src/misc.cpp

@@ -153,7 +153,7 @@ int cpu_count() {
 /// timed_wait() waits for msec milliseconds. It is mainly an helper to wrap
 /// conversion from milliseconds to struct timespec, as used by pthreads.
 
-void timed_wait(WaitCondition* sleepCond, Lock* sleepLock, int msec) {
+void timed_wait(WaitCondition& sleepCond, Lock& sleepLock, int msec) {
 
 #if defined(_MSC_VER)
   int tm = msec;

src/misc.h

@@ -29,7 +29,7 @@
 extern const std::string engine_info(bool to_uci = false);
 extern int system_time();
 extern int cpu_count();
-extern void timed_wait(WaitCondition*, Lock*, int);
+extern void timed_wait(WaitCondition&, Lock&, int);
 extern void prefetch(char* addr);
 
 extern void dbg_hit_on(bool b);

src/search.cpp

@@ -822,7 +822,7 @@ split_point_start: // At split points actual search starts from here
                            && tte->depth() >= depth - 3 * ONE_PLY;
     if (SpNode)
     {
-        lock_grab(&(sp->lock));
+        lock_grab(sp->lock);
         bestValue = sp->bestValue;
         moveCount = sp->moveCount;
 
@@ -854,7 +854,7 @@ split_point_start: // At split points actual search starts from here
       if (SpNode)
       {
           moveCount = ++sp->moveCount;
-          lock_release(&(sp->lock));
+          lock_release(sp->lock);
       }
       else
           moveCount++;
@@ -925,7 +925,7 @@ split_point_start: // At split points actual search starts from here
               && (!threatMove || !connected_threat(pos, move, threatMove)))
           {
               if (SpNode)
-                  lock_grab(&(sp->lock));
+                  lock_grab(sp->lock);
 
               continue;
           }
@@ -940,7 +940,7 @@ split_point_start: // At split points actual search starts from here
           if (futilityValue < beta)
           {
               if (SpNode)
-                  lock_grab(&(sp->lock));
+                  lock_grab(sp->lock);
 
               continue;
           }
@@ -950,7 +950,7 @@ split_point_start: // At split points actual search starts from here
               && pos.see_sign(move) < 0)
           {
               if (SpNode)
-                  lock_grab(&(sp->lock));
+                  lock_grab(sp->lock);
 
               continue;
           }
@@ -1015,7 +1015,7 @@ split_point_start: // At split points actual search starts from here
       // Step 18. Check for new best move
       if (SpNode)
       {
-          lock_grab(&(sp->lock));
+          lock_grab(sp->lock);
           bestValue = sp->bestValue;
           alpha = sp->alpha;
       }
@@ -1134,7 +1134,7 @@ split_point_start: // At split points actual search starts from here
         // Here we have the lock still grabbed
         sp->is_slave[pos.thread()] = false;
         sp->nodes += pos.nodes_searched();
-        lock_release(&(sp->lock));
+        lock_release(sp->lock);
     }
 
     assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
@@ -1858,12 +1858,12 @@ void Thread::idle_loop(SplitPoint* sp) {
           }
 
           // Grab the lock to avoid races with Thread::wake_up()
-          lock_grab(&sleepLock);
+          lock_grab(sleepLock);
 
           // If we are master and all slaves have finished don't go to sleep
           if (sp && Threads.split_point_finished(sp))
           {
-              lock_release(&sleepLock);
+              lock_release(sleepLock);
               break;
           }
 
@@ -1872,9 +1872,9 @@ void Thread::idle_loop(SplitPoint* sp) {
           // in the meanwhile, allocated us and sent the wake_up() call before we
           // had the chance to grab the lock.
           if (do_sleep || !is_searching)
-              cond_wait(&sleepCond, &sleepLock);
+              cond_wait(sleepCond, sleepLock);
 
-          lock_release(&sleepLock);
+          lock_release(sleepLock);
       }
 
       // If this thread has been assigned work, launch a search
@@ -1917,8 +1917,8 @@ void Thread::idle_loop(SplitPoint* sp) {
       {
           // Because sp->is_slave[] is reset under lock protection,
           // be sure sp->lock has been released before to return.
-          lock_grab(&(sp->lock));
-          lock_release(&(sp->lock));
+          lock_grab(sp->lock);
+          lock_release(sp->lock);
           return;
       }
   }

src/thread.cpp

@@ -64,9 +64,9 @@ namespace { extern "C" {
 
 void Thread::wake_up() {
 
-  lock_grab(&sleepLock);
-  cond_signal(&sleepCond);
-  lock_release(&sleepLock);
+  lock_grab(sleepLock);
+  cond_signal(sleepCond);
+  lock_release(sleepLock);
 }
 
 
@@ -153,17 +153,17 @@ void ThreadsManager::set_size(int cnt) {
 void ThreadsManager::init() {
 
   // Initialize sleep condition and lock used by thread manager
-  cond_init(&sleepCond);
-  lock_init(&threadsLock);
+  cond_init(sleepCond);
+  lock_init(threadsLock);
 
   // Initialize thread's sleep conditions and split point locks
   for (int i = 0; i <= MAX_THREADS; i++)
   {
-      lock_init(&threads[i].sleepLock);
-      cond_init(&threads[i].sleepCond);
+      lock_init(threads[i].sleepLock);
+      cond_init(threads[i].sleepCond);
 
       for (int j = 0; j < MAX_ACTIVE_SPLIT_POINTS; j++)
-          lock_init(&(threads[i].splitPoints[j].lock));
+          lock_init(threads[i].splitPoints[j].lock);
   }
 
   // Allocate main thread tables to call evaluate() also when not searching
@@ -177,12 +177,7 @@ void ThreadsManager::init() {
       threads[i].do_sleep = (i != 0); // Avoid a race with start_thinking()
       threads[i].threadID = i;
 
-#if defined(_MSC_VER)
-      threads[i].handle = CreateThread(NULL, 0, start_routine, &threads[i], 0, NULL);
-      bool ok = (threads[i].handle != NULL);
-#else
-      bool ok = !pthread_create(&threads[i].handle, NULL, start_routine, &threads[i]);
-#endif
+      bool ok = thread_create(threads[i].handle, start_routine, threads[i]);
 
       if (!ok)
       {
@@ -202,24 +197,18 @@ void ThreadsManager::exit() {
       threads[i].do_terminate = true; // Search must be already finished
       threads[i].wake_up();
 
-      // Wait for thread termination
-#if defined(_MSC_VER)
-      WaitForSingleObject(threads[i].handle, INFINITE);
-      CloseHandle(threads[i].handle);
-#else
-      pthread_join(threads[i].handle, NULL);
-#endif
+      thread_join(threads[i].handle); // Wait for thread termination
 
       // Now we can safely destroy associated locks and wait conditions
-      lock_destroy(&threads[i].sleepLock);
-      cond_destroy(&threads[i].sleepCond);
+      lock_destroy(threads[i].sleepLock);
+      cond_destroy(threads[i].sleepCond);
 
       for (int j = 0; j < MAX_ACTIVE_SPLIT_POINTS; j++)
-          lock_destroy(&(threads[i].splitPoints[j].lock));
+          lock_destroy(threads[i].splitPoints[j].lock);
   }
 
-  lock_destroy(&threadsLock);
-  cond_destroy(&sleepCond);
+  lock_destroy(threadsLock);
+  cond_destroy(sleepCond);
 }
 
 
@@ -310,7 +299,7 @@ Value ThreadsManager::split(Position& pos, Stack* ss, Value alpha, Value beta,
   // Try to allocate available threads and ask them to start searching setting
   // is_searching flag. This must be done under lock protection to avoid concurrent
   // allocation of the same slave by another master.
-  lock_grab(&threadsLock);
+  lock_grab(threadsLock);
 
   for (i = 0; !Fake && i < activeThreads && workersCnt < maxThreadsPerSplitPoint; i++)
       if (threads[i].is_available_to(master))
@@ -326,7 +315,7 @@ Value ThreadsManager::split(Position& pos, Stack* ss, Value alpha, Value beta,
               threads[i].wake_up();
       }
 
-  lock_release(&threadsLock);
+  lock_release(threadsLock);
 
   // We failed to allocate even one slave, return
   if (!Fake && workersCnt == 1)
@@ -349,12 +338,12 @@ Value ThreadsManager::split(Position& pos, Stack* ss, Value alpha, Value beta,
   // We have returned from the idle loop, which means that all threads are
   // finished. Note that changing state and decreasing activeSplitPoints is done
   // under lock protection to avoid a race with Thread::is_available_to().
-  lock_grab(&threadsLock);
+  lock_grab(threadsLock);
 
   masterThread.is_searching = true;
   masterThread.activeSplitPoints--;
 
-  lock_release(&threadsLock);
+  lock_release(threadsLock);
 
   masterThread.splitPoint = sp->parent;
   pos.set_nodes_searched(pos.nodes_searched() + sp->nodes);
@@ -375,9 +364,9 @@ void Thread::timer_loop() {
 
   while (!do_terminate)
   {
-      lock_grab(&sleepLock);
-      timed_wait(&sleepCond, &sleepLock, maxPly ? maxPly : INT_MAX);
-      lock_release(&sleepLock);
+      lock_grab(sleepLock);
+      timed_wait(sleepCond, sleepLock, maxPly ? maxPly : INT_MAX);
+      lock_release(sleepLock);
       check_time();
   }
 }
@@ -390,10 +379,10 @@ void ThreadsManager::set_timer(int msec) {
 
   Thread& timer = threads[MAX_THREADS];
 
-  lock_grab(&timer.sleepLock);
+  lock_grab(timer.sleepLock);
   timer.maxPly = msec;
-  cond_signal(&timer.sleepCond); // Wake up and restart the timer
-  lock_release(&timer.sleepLock);
+  cond_signal(timer.sleepCond); // Wake up and restart the timer
+  lock_release(timer.sleepLock);
 }
 
 
@@ -404,20 +393,20 @@ void Thread::main_loop() {
 
   while (true)
   {
-      lock_grab(&sleepLock);
+      lock_grab(sleepLock);
 
       do_sleep = true; // Always return to sleep after a search
       is_searching = false;
 
       while (do_sleep && !do_terminate)
       {
-          cond_signal(&Threads.sleepCond); // Wake up UI thread if needed
-          cond_wait(&sleepCond, &sleepLock);
+          cond_signal(Threads.sleepCond); // Wake up UI thread if needed
+          cond_wait(sleepCond, sleepLock);
       }
 
       is_searching = true;
 
-      lock_release(&sleepLock);
+      lock_release(sleepLock);
 
       if (do_terminate)
           return;
@@ -436,11 +425,11 @@ void ThreadsManager::start_thinking(const Position& pos, const LimitsType& limit
                                     const std::set<Move>& searchMoves, bool async) {
   Thread& main = threads[0];
 
-  lock_grab(&main.sleepLock);
+  lock_grab(main.sleepLock);
 
   // Wait main thread has finished before to launch a new search
   while (!main.do_sleep)
-      cond_wait(&sleepCond, &main.sleepLock);
+      cond_wait(sleepCond, main.sleepLock);
 
   // Copy input arguments to initialize the search
   RootPosition.copy(pos, 0);
@@ -458,13 +447,13 @@ void ThreadsManager::start_thinking(const Position& pos, const LimitsType& limit
   Signals.stop = Signals.failedLowAtRoot = false;
 
   main.do_sleep = false;
-  cond_signal(&main.sleepCond); // Wake up main thread and start searching
+  cond_signal(main.sleepCond); // Wake up main thread and start searching
 
   if (!async)
       while (!main.do_sleep)
-          cond_wait(&sleepCond, &main.sleepLock);
+          cond_wait(sleepCond, main.sleepLock);
 
-  lock_release(&main.sleepLock);
+  lock_release(main.sleepLock);
 }
 
 
@@ -478,14 +467,14 @@ void ThreadsManager::stop_thinking() {
 
   Search::Signals.stop = true;
 
-  lock_grab(&main.sleepLock);
+  lock_grab(main.sleepLock);
 
-  cond_signal(&main.sleepCond); // In case is waiting for stop or ponderhit
+  cond_signal(main.sleepCond); // In case is waiting for stop or ponderhit
 
   while (!main.do_sleep)
-      cond_wait(&sleepCond, &main.sleepLock);
+      cond_wait(sleepCond, main.sleepLock);
 
-  lock_release(&main.sleepLock);
+  lock_release(main.sleepLock);
 }
 
 
@@ -502,10 +491,10 @@ void ThreadsManager::wait_for_stop_or_ponderhit() {
 
   Thread& main = threads[0];
 
-  lock_grab(&main.sleepLock);
+  lock_grab(main.sleepLock);
 
   while (!Signals.stop)
-      cond_wait(&main.sleepCond, &main.sleepLock);
+      cond_wait(main.sleepCond, main.sleepLock);
 
-  lock_release(&main.sleepLock);
+  lock_release(main.sleepLock);
 }

src/thread.h

@@ -80,17 +80,12 @@ struct Thread {
   int maxPly;
   Lock sleepLock;
   WaitCondition sleepCond;
+  ThreadHandle handle;
   SplitPoint* volatile splitPoint;
   volatile int activeSplitPoints;
   volatile bool is_searching;
   volatile bool do_sleep;
   volatile bool do_terminate;
-
-#if defined(_MSC_VER)
-  HANDLE handle;
-#else
-  pthread_t handle;
-#endif
 };