Support for LTTNG and ETW tracing

This commit introduces minimal support for instrumentation within Qt.
Currently, only LTTNG/Linux and ETW/Windows are supported.

Change-Id: I59b48cf83acf5532a998bb493e6379e9177e14c8
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@qt.io>
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

10 files changed, 196 insertions, 5 deletions

diff --git a/src/corelib/configure.json b/src/corelib/configure.json
index 8cd73d6ce4..9f9512942a 100644
--- a/src/corelib/configure.json
+++ b/src/corelib/configure.json
@@ -15,7 +15,8 @@
             "posix-ipc": { "type": "boolean", "name": "ipc_posix" },
             "pps": { "type": "boolean", "name": "qqnx_pps" },
             "slog2": "boolean",
-            "syslog": "boolean"
+            "syslog": "boolean",
+            "trace": { "type": "optionalString", "values": [ "etw", "lttng", "no", "yes" ] }
         }
     },
 
@@ -147,6 +148,18 @@
                 "-lrt"
             ]
         },
+        "lttng-ust": {
+            "label": "lttng-ust",
+            "test": {
+                "include": "lttng/ust-events.h",
+                "main": "lttng_session_destroy(nullptr);"
+            },
+            "sources": [
+                { "type": "pkgConfig", "args": "lttng-ust" },
+                "-llttng-ust"
+            ],
+            "use": "libdl"
+        },
         "pcre2": {
             "label": "PCRE2",
             "test": {
@@ -858,6 +871,22 @@
             "section": "Utilities",
             "output": [ "publicFeature" ]
         },
+        "lttng": {
+            "label": "LTTNG",
+            "autoDetect": false,
+            "enable": "input.trace == 'lttng' || (input.trace =='yes' && config.linux)",
+            "disable": "input.trace == 'etw' || input.trace =='no'",
+            "condition": "config.linux && libs.lttng-ust",
+            "output": [ "privateFeature" ]
+        },
+        "etw": {
+            "label": "ETW",
+            "autoDetect": false,
+            "enable": "input.trace == 'etw' || (input.trace == 'yes' && config.win32)",
+            "disable": "input.trace == 'lttng' || input.trace == 'no'",
+            "condition": "config.win32",
+            "output": [ "privateFeature" ]
+        },
         "topleveldomain": {
             "label": "QUrl::topLevelDomain()",
             "purpose": "Provides support for extracting the top level domain from URLs.
@@ -908,6 +937,11 @@ Please apply the patch corresponding to your Standard Library vendor, found in
                 "iconv",
                 "icu",
                 {
+                    "message": "Tracing backend",
+                    "type": "firstAvailableFeature",
+                    "args": "etw lttng"
+                },
+                {
                     "section": "Logging backends",
                     "entries": [
                         "journald", "syslog", "slog2"
diff --git a/src/corelib/corelib.pro b/src/corelib/corelib.pro
index 4cce7c0df3..2079d2117f 100644
--- a/src/corelib/corelib.pro
+++ b/src/corelib/corelib.pro
@@ -6,6 +6,9 @@ MODULE = core     # not corelib, as per project file
 MODULE_CONFIG = moc resources
 !isEmpty(QT_NAMESPACE): MODULE_DEFINES = QT_NAMESPACE=$$QT_NAMESPACE
 
+TRACEPOINT_PROVIDER = $$PWD/qtcore.tracepoints
+CONFIG += qt_tracepoints
+
 CONFIG += $$MODULE_CONFIG
 DEFINES += $$MODULE_DEFINES
 DEFINES += QT_NO_USING_NAMESPACE QT_NO_FOREACH
diff --git a/src/corelib/global/qconfig-bootstrapped.h b/src/corelib/global/qconfig-bootstrapped.h
index 0df593941d..86ef1a2613 100644
--- a/src/corelib/global/qconfig-bootstrapped.h
+++ b/src/corelib/global/qconfig-bootstrapped.h
@@ -78,6 +78,7 @@
 #define QT_FEATURE_cxx11_random (QT_HAS_INCLUDE(<random>) ? 1 : -1)
 #define QT_NO_DATASTREAM
 #define QT_FEATURE_datetimeparser -1
+#define QT_FEATURE_etw -1
 #define QT_FEATURE_getauxval (QT_HAS_INCLUDE(<sys/auxv.h>) ? 1 : -1)
 #define QT_FEATURE_getentropy -1
 #define QT_NO_GEOM_VARIANT
@@ -92,6 +93,7 @@
 #else
 # define QT_FEATURE_linkat -1
 #endif
+#define QT_FEATURE_lttng -1
 #define QT_NO_QOBJECT
 #define QT_FEATURE_process -1
 #define QT_FEATURE_regularexpression -1
diff --git a/src/corelib/global/qtrace_p.h b/src/corelib/global/qtrace_p.h
new file mode 100644
index 0000000000..ab8fc14af5
--- /dev/null
+++ b/src/corelib/global/qtrace_p.h
@@ -0,0 +1,126 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Rafael Roquetto <rafael.roquetto@kdab.com>
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** 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 Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** 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-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QTRACE_P_H
+#define QTRACE_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+/*
+ * The Qt tracepoints API consists of only three macros:
+ *
+ *     - Q_TRACE(tracepoint, args...)
+ *       Fires 'tracepoint' if it is enabled.
+ *
+ *     - Q_UNCONDITIONAL_TRACE(tracepoint, args...)
+ *       Fires 'tracepoint' unconditionally: no check is performed to query
+ *       whether 'tracepoint' is enabled.
+ *
+ *     - Q_TRACE_ENABLED(tracepoint)
+ *       Returns 'true' if 'tracepoint' is enabled; false otherwise.
+ *
+ * When using LTTNG, Q_TRACE, Q_UNCONDITIONAL_TRACE and Q_TRACE_ENABLED map
+ * ultimately to tracepoint(), do_tracepoint() and tracepoint_enabled(),
+ * respectively, described on the lttng-ust manpage (man 3 lttng-ust).
+ *
+ * On ETW, Q_TRACE() and Q_UNCONDITIONAL_TRACE() are equivalent, ultimately
+ * amounting to a call to TraceLoggingWrite(), whereas Q_TRACE_ENABLED()
+ * wraps around TraceLoggingProviderEnabled().
+ *
+ * A tracepoint provider is defined in a separate file, that follows the
+ * following format:
+ *
+ *     tracepoint_name(arg_type arg_name, ...)
+ *
+ * For instance:
+ *
+ *     qcoreapplication_ctor(int argc, const char * const argv)
+ *     qcoreapplication_foo(int argc, const char[10] argv)
+ *     qcoreapplication_baz(const char[len] some_string, unsigned int len)
+ *     qcoreapplication_qstring(const QString &foo)
+ *     qcoreapplication_qrect(const QRect &rect)
+ *
+ * The provider file is then parsed by src/tools/tracegen, which can be
+ * switched to output either ETW or LTTNG tracepoint definitions. The provider
+ * name is deduced to be basename(provider_file).
+ *
+ * To use the above (inside qtcore), you need to include
+ * <providername_tracepoints_p.h>. After that, the following call becomes
+ * possible:
+ *
+ *     Q_TRACE(qcoreapplication_qrect, myRect);
+ *
+ * Currently, all C++ primitive non-pointer types are supported for
+ * arguments. Additionally, char * is supported, and is assumed to
+ * be a NULL-terminated string. Finally, the following subset of Qt types also
+ * currently supported:
+ *
+ *      - QString
+ *      - QByteArray
+ *      - QUrl
+ *      - QRect
+ *
+ * Dynamic arrays are supported using the syntax illustrated by
+ * qcoreapplication_baz above.
+ */
+
+QT_BEGIN_NAMESPACE
+
+#if defined(Q_TRACEPOINT) && !defined(QT_BOOTSTRAPPED)
+#  define Q_TRACE(x, ...) QtPrivate::trace_ ## x(__VA_ARGS__)
+#  define Q_UNCONDITIONAL_TRACE(x, ...) QtPrivate::do_trace_ ## x(__VA_ARGS__)
+#  define Q_TRACE_ENABLED(x) QtPrivate::trace_ ## x ## _enabled()
+#else
+#  define Q_TRACE(x, ...)
+#  define Q_UNCONDITIONAL_TRACE(x, ...)
+#  define Q_TRACE_ENABLED(x) false
+#endif // defined(Q_TRACEPOINT) && !defined(QT_BOOTSTRAPPED)
+
+QT_END_NAMESPACE
+
+#endif // QTRACE_P_H
diff --git a/src/corelib/kernel/qcoreapplication.cpp b/src/corelib/kernel/qcoreapplication.cpp
index e93a14c116..4bab0b9f01 100644
--- a/src/corelib/kernel/qcoreapplication.cpp
+++ b/src/corelib/kernel/qcoreapplication.cpp
@@ -116,6 +116,12 @@
 #  include <taskLib.h>
 #endif
 
+#ifdef QT_BOOTSTRAPPED
+#include <private/qtrace_p.h>
+#else
+#include <qtcore_tracepoints_p.h>
+#endif
+
 #include <algorithm>
 
 QT_BEGIN_NAMESPACE
@@ -790,6 +796,8 @@ QCoreApplication::QCoreApplication(int &argc, char **argv
 
 void QCoreApplicationPrivate::init()
 {
+    Q_TRACE(qcoreapplicationprivate_init_entry);
+
 #if defined(Q_OS_MACOS)
     QMacAutoReleasePool pool;
 #endif
@@ -873,6 +881,8 @@ void QCoreApplicationPrivate::init()
 #ifndef QT_NO_QOBJECT
     is_app_running = true; // No longer starting up.
 #endif
+
+    Q_TRACE(qcoreapplicationprivate_init_exit);
 }
 
 /*!
diff --git a/src/corelib/plugin/qfactoryloader.cpp b/src/corelib/plugin/qfactoryloader.cpp
index 0cc193c325..a4be18a67f 100644
--- a/src/corelib/plugin/qfactoryloader.cpp
+++ b/src/corelib/plugin/qfactoryloader.cpp
@@ -54,6 +54,8 @@
 #include "qjsonobject.h"
 #include "qjsonarray.h"
 
+#include <qtcore_tracepoints_p.h>
+
 QT_BEGIN_NAMESPACE
 
 class QFactoryLoaderPrivate : public QObjectPrivate
@@ -142,6 +144,9 @@ void QFactoryLoader::update()
             if (qt_debug_component()) {
                 qDebug() << "QFactoryLoader::QFactoryLoader() looking at" << fileName;
             }
+
+            Q_TRACE(qfactoryloader_update, fileName);
+
             library = QLibraryPrivate::findOrCreate(QFileInfo(fileName).canonicalFilePath());
             if (!library->isPlugin()) {
                 if (qt_debug_component()) {
diff --git a/src/corelib/plugin/qlibrary.cpp b/src/corelib/plugin/qlibrary.cpp
index ebad7f1751..bca6918b4a 100644
--- a/src/corelib/plugin/qlibrary.cpp
+++ b/src/corelib/plugin/qlibrary.cpp
@@ -64,6 +64,8 @@
 #include "qelfparser_p.h"
 #include "qmachparser_p.h"
 
+#include <qtcore_tracepoints_p.h>
+
 QT_BEGIN_NAMESPACE
 
 #ifdef QT_NO_DEBUG
@@ -535,6 +537,8 @@ bool QLibraryPrivate::load()
     if (fileName.isEmpty())
         return false;
 
+    Q_TRACE(qlibraryprivate_load_entry, fileName);
+
     bool ret = load_sys();
     if (qt_debug_component()) {
         if (ret) {
@@ -551,6 +555,8 @@ bool QLibraryPrivate::load()
         installCoverageTool(this);
     }
 
+    Q_TRACE(qlibraryprivate_load_exit, ret);
+
     return ret;
 }
 
diff --git a/src/corelib/plugin/quuid.cpp b/src/corelib/plugin/quuid.cpp
index 3a1c0495fe..5dfbf23c33 100644
--- a/src/corelib/plugin/quuid.cpp
+++ b/src/corelib/plugin/quuid.cpp
@@ -143,7 +143,6 @@ static QUuid _q_uuidFromHex(const char *src)
     return QUuid();
 }
 
-#ifndef QT_BOOTSTRAPPED
 static QUuid createFromName(const QUuid &ns, const QByteArray &baseData, QCryptographicHash::Algorithm algorithm, int version)
 {
     QByteArray hashResult;
@@ -166,7 +165,6 @@ static QUuid createFromName(const QUuid &ns, const QByteArray &baseData, QCrypto
 
     return result;
 }
-#endif
 
 /*!
     \class QUuid
@@ -488,12 +486,12 @@ QUuid QUuid::createUuidV3(const QUuid &ns, const QByteArray &baseData)
 {
     return createFromName(ns, baseData, QCryptographicHash::Md5, 3);
 }
+#endif
 
 QUuid QUuid::createUuidV5(const QUuid &ns, const QByteArray &baseData)
 {
     return createFromName(ns, baseData, QCryptographicHash::Sha1, 5);
 }
-#endif
 
 /*!
   Creates a QUuid object from the binary representation of the UUID, as
diff --git a/src/corelib/plugin/quuid.h b/src/corelib/plugin/quuid.h
index ee0a9f9dac..014b69831e 100644
--- a/src/corelib/plugin/quuid.h
+++ b/src/corelib/plugin/quuid.h
@@ -192,18 +192,20 @@ public:
     static QUuid createUuid();
 #ifndef QT_BOOTSTRAPPED
     static QUuid createUuidV3(const QUuid &ns, const QByteArray &baseData);
+#endif
     static QUuid createUuidV5(const QUuid &ns, const QByteArray &baseData);
+#ifndef QT_BOOTSTRAPPED
     static inline QUuid createUuidV3(const QUuid &ns, const QString &baseData)
     {
         return QUuid::createUuidV3(ns, baseData.toUtf8());
     }
+#endif
 
     static inline QUuid createUuidV5(const QUuid &ns, const QString &baseData)
     {
         return QUuid::createUuidV5(ns, baseData.toUtf8());
     }
 
-#endif
 
     QUuid::Variant variant() const Q_DECL_NOTHROW;
     QUuid::Version version() const Q_DECL_NOTHROW;
diff --git a/src/corelib/qtcore.tracepoints b/src/corelib/qtcore.tracepoints
new file mode 100644
index 0000000000..e6b666ac74
--- /dev/null
+++ b/src/corelib/qtcore.tracepoints
@@ -0,0 +1,5 @@
+qcoreapplicationprivate_init_entry()
+qcoreapplicationprivate_init_exit()
+qfactoryloader_update(const QString &fileName)
+qlibraryprivate_load_entry(const QString &fileName)
+qlibraryprivate_load_exit(bool success)