Benchmarks: Provide infrastructure for benchmarks

... and use it for the profiling report.

Instantiate a Utils::Benchmarker(...) to report a data point (which
will be created at destruction time, reporting the live-time of the
object).

Alternatively you can use Utils::Benchmarker::report(...) to record
your data point.

Independent of how you create a datapoint, it will be reported through
the qtc.benchmark logging category and can get pushed to a database
from a script parsing creator's output.

Note: The plugin-loading uses the existing -profiling infrastructure,
so you need to start Creator with -profile to see data points.

Change-Id: I18e6b84137d0f49ee5e12e7c3d75323005ce5a29
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/libs/utils/benchmarker.cpp

@@ -0,0 +1,67 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#include "benchmarker.h"
+
+#include <QLoggingCategory>
+
+static Q_LOGGING_CATEGORY(benchmarksLog, "qtc.benchmark");
+
+namespace Utils {
+
+Benchmarker::Benchmarker(const QString &testsuite, const QString &testcase,
+                         const QString &tagData) :
+    m_tagData(tagData),
+    m_testsuite(testsuite),
+    m_testcase(testcase)
+{
+    m_timer.start();
+}
+
+Benchmarker::~Benchmarker()
+{
+    if (m_timer.isValid())
+        report(m_timer.elapsed());
+}
+
+void Benchmarker::report(qint64 ms)
+{
+    m_timer.invalidate();
+    report(m_testsuite, m_testcase, ms, m_tagData);
+}
+
+void Benchmarker::report(const QString &testsuite, const QString &testcase, qint64 ms,
+                         const QString &tags)
+{
+    QString t = "unit=ms";
+    if (!tags.isEmpty())
+        t += "," + tags;
+
+    qCDebug(benchmarksLog, "%s::%s: %lld { %s }",
+            testsuite.toUtf8().data(), testcase.toUtf8().data(), ms, t.toUtf8().data());
+}
+
+
+} // namespace Utils