Fix crashes in tst_qthreadpool on Windows.

Qt 4.8 shows frequent crashes in runMultiple apparently caused
by the QMutex construction in the free functions by different
threads. Use a common QMutex class member instead.

Change-Id: I851d4e2d3637a7b4f404ed843f5360c10caa21f5
Reviewed-by: Mitch Curtis <mitch.curtis@digia.com>
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
(cherry picked from qtbase/ced523af7a3559b0f30dd2a4406e05418ff7ec89)

1 files changed, 28 insertions, 6 deletions

diff --git a/tests/auto/qthreadpool/tst_qthreadpool.cpp b/tests/auto/qthreadpool/tst_qthreadpool.cpp
index 49a496c416..5d134ab0e1 100644
--- a/tests/auto/qthreadpool/tst_qthreadpool.cpp
+++ b/tests/auto/qthreadpool/tst_qthreadpool.cpp
@@ -64,6 +64,12 @@ QRunnable *createTask(FunctionPointer pointer)
 class tst_QThreadPool : public QObject
 {
     Q_OBJECT
+public:
+    tst_QThreadPool();
+    ~tst_QThreadPool();
+
+    static QMutex *functionTestMutex;
+
 private slots:
     void runFunction();
     void createThreadRunFunction();
@@ -92,8 +98,24 @@ private slots:
     void waitForDoneTimeout();
     void destroyingWaitsForTasksToFinish();
     void stressTest();
+
+private:
+    QMutex m_functionTestMutex;
 };
 
+
+QMutex *tst_QThreadPool::functionTestMutex = 0;
+
+tst_QThreadPool::tst_QThreadPool()
+{
+    tst_QThreadPool::functionTestMutex = &m_functionTestMutex;
+}
+
+tst_QThreadPool::~tst_QThreadPool()
+{
+    tst_QThreadPool::functionTestMutex = 0;
+}
+
 int testFunctionCount;
 
 void sleepTestFunction()
@@ -114,19 +136,19 @@ void noSleepTestFunction()
 
 void sleepTestFunctionMutex()
 {
-    static QMutex testMutex;
+    Q_ASSERT(tst_QThreadPool::functionTestMutex);
     QTest::qSleep(1000);
-    testMutex.lock();
+    tst_QThreadPool::functionTestMutex->lock();
     ++testFunctionCount;
-    testMutex.unlock();
+    tst_QThreadPool::functionTestMutex->unlock();
 }
 
 void noSleepTestFunctionMutex()
 {
-    static QMutex testMutex;
-    testMutex.lock();
+    Q_ASSERT(tst_QThreadPool::functionTestMutex);
+    tst_QThreadPool::functionTestMutex->lock();
     ++testFunctionCount;
-    testMutex.unlock();
+    tst_QThreadPool::functionTestMutex->unlock();
 }
 
 void tst_QThreadPool::runFunction()