1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
|
// Copyright (C) 2017 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com, author Rafael Roquetto <rafael.roquetto@kdab.com>
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#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 five macros:
*
* - Q_TRACE(tracepoint, args...)
* Fires 'tracepoint' if it is enabled.
*
* - Q_TRACE_EXIT(tracepoint, args...)
* Fires 'tracepoint' if it is enabled when the current scope exists.
*
* - Q_TRACE_SCOPE(tracepoint, args...)
* Wrapper around Q_TRACE/_EXIT to trace entry and exit. First it traces
* `${tracepoint}_entry` and then `${tracepoint}_exit` on scope exit.
*
* - 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.
*/
#include <QtCore/private/qglobal_p.h>
#include <QtCore/qscopeguard.h>
QT_BEGIN_NAMESPACE
#if defined(Q_TRACEPOINT) && !defined(QT_BOOTSTRAPPED)
# define Q_HAS_TRACEPOINTS 1
# define Q_TRACE(x, ...) QtPrivate::trace_ ## x(__VA_ARGS__)
# define Q_TRACE_EXIT(x, ...) \
const auto qTraceExit_ ## x ## __COUNTER__ = qScopeGuard([&]() { Q_TRACE(x, __VA_ARGS__); });
# define Q_TRACE_SCOPE(x, ...) \
Q_TRACE(x ## _entry, __VA_ARGS__); \
Q_TRACE_EXIT(x ## _exit);
# define Q_UNCONDITIONAL_TRACE(x, ...) QtPrivate::do_trace_ ## x(__VA_ARGS__)
# define Q_TRACE_ENABLED(x) QtPrivate::trace_ ## x ## _enabled()
#else
# define Q_HAS_TRACEPOINTS 0
# define Q_TRACE(x, ...)
# define Q_TRACE_EXIT(x, ...)
# define Q_TRACE_SCOPE(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
|
