4 files changed, 25 insertions, 15 deletions
diff --git a/src/corelib/io/qresource.cpp b/src/corelib/io/qresource.cpp
index 1ead114235..96957ac11d 100644
--- a/src/corelib/io/qresource.cpp
+++ b/src/corelib/io/qresource.cpp
@@ -1194,9 +1194,10 @@ protected:
 private:
     uchar *map(qint64 offset, qint64 size, QFile::MemoryMapFlags flags);
     bool unmap(uchar *ptr);
+    void uncompress() const;
     qint64 offset;
     QResource resource;
-    QByteArray uncompressed;
+    mutable QByteArray uncompressed;
 protected:
     QResourceFileEnginePrivate() : offset(0) { }
 };
@@ -1231,13 +1232,6 @@ QResourceFileEngine::QResourceFileEngine(const QString &file) :
 {
     Q_D(QResourceFileEngine);
     d->resource.setFileName(file);
-    if(d->resource.isCompressed() && d->resource.size()) {
-#ifndef QT_NO_COMPRESS
-        d->uncompressed = qUncompress(d->resource.data(), d->resource.size());
-#else
-        Q_ASSERT(!"QResourceFileEngine::open: Qt built without support for compression");
-#endif
-    }
 }
 
 QResourceFileEngine::~QResourceFileEngine()
@@ -1259,6 +1253,7 @@ bool QResourceFileEngine::open(QIODevice::OpenMode flags)
     }
     if(flags & QIODevice::WriteOnly)
         return false;
+    d->uncompress();
     if (!d->resource.isValid()) {
         d->errorString = qt_error_string(ENOENT);
         return false;
@@ -1324,8 +1319,10 @@ qint64 QResourceFileEngine::size() const
     Q_D(const QResourceFileEngine);
     if(!d->resource.isValid())
         return 0;
-    if(d->resource.isCompressed())
+    if (d->resource.isCompressed()) {
+        d->uncompress();
         return d->uncompressed.size();
+    }
     return d->resource.size();
 }
 
@@ -1493,6 +1490,18 @@ bool QResourceFileEnginePrivate::unmap(uchar *ptr)
     Q_UNUSED(ptr);
     return true;
 }
+
+void QResourceFileEnginePrivate::uncompress() const
+{
+    if (resource.isCompressed() && uncompressed.isEmpty() && resource.size()) {
+#ifndef QT_NO_COMPRESS
+        uncompressed = qUncompress(resource.data(), resource.size());
+#else
+        Q_ASSERT(!"QResourceFileEngine::open: Qt built without support for compression");
+#endif
+    }
+}
+
 #endif // !defined(QT_BOOTSTRAPPED)
 
 QT_END_NAMESPACE
diff --git a/src/corelib/tools/qdatetime.cpp b/src/corelib/tools/qdatetime.cpp
index 7cc86eb3f1..e18c220884 100644
--- a/src/corelib/tools/qdatetime.cpp
+++ b/src/corelib/tools/qdatetime.cpp
@@ -4699,7 +4699,7 @@ QDateTime QDateTime::fromString(const QString &string, const QString &format)
     Q_UNUSED(string);
     Q_UNUSED(format);
 #endif
-    return QDateTime(QDate(), QTime(-1, -1, -1));
+    return QDateTime();
 }
 
 #endif // QT_NO_DATESTRING
diff --git a/src/corelib/tools/qdatetimeparser.cpp b/src/corelib/tools/qdatetimeparser.cpp
index c1abdf11a7..fbf91fe8a4 100644
--- a/src/corelib/tools/qdatetimeparser.cpp
+++ b/src/corelib/tools/qdatetimeparser.cpp
@@ -1555,10 +1555,7 @@ QString QDateTimeParser::SectionNode::format() const
         qWarning("QDateTimeParser::sectionFormat Internal error 2");
         return QString();
     }
-
-    QString str;
-    str.fill(fillChar, count);
-    return str;
+    return QString(count, fillChar);
 }
 
 
diff --git a/src/corelib/tools/qelapsedtimer_unix.cpp b/src/corelib/tools/qelapsedtimer_unix.cpp
index 1e672531c8..e1fc77fb4c 100644
--- a/src/corelib/tools/qelapsedtimer_unix.cpp
+++ b/src/corelib/tools/qelapsedtimer_unix.cpp
@@ -115,7 +115,11 @@ static inline void qt_clock_gettime(clockid_t clock, struct timespec *ts)
 
 static int unixCheckClockType()
 {
-#if (_POSIX_MONOTONIC_CLOCK-0 == 0) && defined(_SC_MONOTONIC_CLOCK)
+#ifdef Q_OS_LINUX
+    // Despite glibc claiming that we should check at runtime, the Linux kernel
+    // always supports the monotonic clock
+    return CLOCK_MONOTONIC;
+#elif (_POSIX_MONOTONIC_CLOCK-0 == 0) && defined(_SC_MONOTONIC_CLOCK)
     // we need a value we can store in a clockid_t that isn't a valid clock
     // check if the valid ones are both non-negative or both non-positive
 #  if CLOCK_MONOTONIC >= 0 && CLOCK_REALTIME >= 0