From c1b067ea8169e1d37e2a120334406f1f115298bb Mon Sep 17 00:00:00 2001
From: Thiago Macieira <thiago.macieira@nokia.com>
Date: Mon, 1 Mar 2010 22:40:04 +0100
Subject: Fix strict-aliasing breakage with SunCC: the union trick is a GCC
 extension.

It's probably also an MSVC extension, because the MSVC compiler has never
complained about this fact, nor generated unintended code.

Anyway, the only way is to reinterpret_cast the quintptr. It's not an aliasing
violation to do it because we never access the integer as anything other than
quintptr.

Reviewed-By: Bradley T. Hughes
---
 src/corelib/thread/qmutex.h | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/src/corelib/thread/qmutex.h b/src/corelib/thread/qmutex.h
index 80b50fc..677412e 100644
--- a/src/corelib/thread/qmutex.h
+++ b/src/corelib/thread/qmutex.h
@@ -95,7 +95,7 @@ class Q_CORE_EXPORT QMutexLocker
 {
 public:
     inline explicit QMutexLocker(QMutex *m)
-        : mtx(m)
+        : val(reinterpret_cast<quintptr>(m))
     {
         Q_ASSERT_X((val & quintptr(1u)) == quintptr(0),
                    "QMutexLocker", "QMutex pointer is misaligned");
@@ -105,19 +105,19 @@ public:
 
     inline void unlock()
     {
-        if (mtx) {
+        if (val) {
             if ((val & quintptr(1u)) == quintptr(1u)) {
                 val &= ~quintptr(1u);
-                mtx->unlock();
+                mutex()->unlock();
             }
         }
     }
 
     inline void relock()
     {
-        if (mtx) {
+        if (val) {
             if ((val & quintptr(1u)) == quintptr(0u)) {
-                mtx->lock();
+                mutex()->lock();
                 val |= quintptr(1u);
             }
         }
@@ -140,10 +140,7 @@ public:
 private:
     Q_DISABLE_COPY(QMutexLocker)
 
-    union {
-        QMutex *mtx;
-        quintptr val;
-    };
+    quintptr val;
 };
 
 #else // QT_NO_THREAD
-- 
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