tracetool - a configurable and efficient logging framework for C++

tracetool is a framework created by froglogic for tracing the execution of a C or C++ program and inspecting its state. This is achieved by instrumenting the source code of the target program and linking the recompiled sources against a shared tracelib library.

![Image Of TraceTool GUI] (http://blog.froglogic.com/wp-content/uploads/Screen-Shot-2016-09-15-at-13.39.37.png)

License

tracetool is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

Installation

Building the framework requires

• A C++ compiler, e.g. GCC or Microsoft Visual Studio 2008 or newer
• CMake 3.0.0 or newer
• Qt 5.6
• For building the documentation, Doxygen is needed.

The actual build is the merely a matter of running the commands

cmake -DCMAKE_PREFIX_PATH=<path_to_Qt>
make

On Windows, you may want to pass -G "NMake Makefiles" to cmake to generate Makefiles and then use nmake to use those Makefiles.

Quick Start

Here's a quick step by step guide on how to instrument a basic program so that it generates trace information. Here's the initial source code of the sample program:

#include <iostream>
#include <string>

int main()
{
    using namespace std;

    string name;
    cout << "Please enter your name: ";
    cin >> name;

    cout << "Hello, " << name << "!" << endl;
}

First, instrument the above source code so that the tracelib.h header is included and insert a few calls to various tracelib macros into the source code. Here's the instrumented code:

#include <iostream>
#include <string>

#include "tracelib.h"

int main()
{
    fTrace(0) << "main() entered";

    using namespace std;

    string name;
    cout << "Please enter your name: ";
    cin >> name;

    fWatch(0) << fVar(name);

    cout << "Hello, " << name << "!" << endl;

    fTrace(0) << "main() finished";
}

Save the resulting file to e.g. hello\_instrumented.cpp.

Here's a sample compile line for use with cl.exe (the compiler which comes with Microsoft Visual Studio):

cl /EHsc hello_instrumented.cpp /I <TRACELIB_PREFIX>\include\tracelib
    <TRACELIB_PREFIX>\lib\tracelib.lib
    ws2_32.lib

The resulting binary (hello\_instrumented.exe in the above case) will behave as before. The tracing (and the resulting change to runtime performance) is only activated in case a special configuration file was detected.

Creating a configuration file is a matter of writing some XML. Save the following file as tracelib.xml and store it in the same directory as hello\_instrumented.exe which was built above:

<tracelibConfiguration>
<process>
  <name>hello_instrumented</name>
  <output type="stdout"/>
  <serializer type="plaintext"/>
</process>
</tracelibConfiguration>

Now, running the program will generate quite a bit of additional output:

03.09.2010 16:00:56: Process 2524 [started at 03.09.2010 16:00:56] (Thread 468): [LOG] 'main() entered' hello_instrumented.cpp:8: int __cdecl main(void)
Please enter your name: Max
03.09.2010 16:00:57: Process 2524 [started at 03.09.2010 16:00:56] (Thread 468): [WATCH] hello_instrumented.cpp:16: int __cdecl main(void)
Hello, Max!
03.09.2010 16:00:57: Process 2524 [started at 03.09.2010 16:00:56] (Thread 468): [LOG] 'main() finished' hello_instrumented.cpp:20: int __cdecl main(void)
03.09.2010 16:00:57: Process 2524 [started at 03.09.2010 16:00:56] finished

Components

The tracetool framework consists of multiple components:

• tracelib.dll (resp. libtracelib.so on Linux) is a dynamic library (plus accompanying header files) which has to be linked into any application which wishes to use the tracing functionality.
• tracegui is a GUI for reviewing previously recorded traces as well as recording and watching the trace generated by running applications live.
• traced is a daemon process which collects and stores trace data in the background without running a GUI.Traced applications can be configured to send their output over a network connection to traced.exe. The recorded traces can be sent to other people and reviewed later using tracegui.
• trace2xml is a utility program for dumping a trace database generated by tracegui or traced into an XML file which can then be processed by other scripts.
• xml2trace performs the reverse operation of trace2xml: given an XML file, a .trace file is generated which can be loaded by tracegui.
• convertdb is a helper utility for converting earlier versions of databases with tracelib traces.

Acknowledgements

This project is really just standing on the shoulders of giants. It was made possible by and takes advantage of a few other open source projects:

• The PCRE library is used for matching function names to include in the execution trace via regular expressions.
• For matching functionn names to include in the execution trace via wildcard patterns, the wildcmp function is used.
• Reading the tracelib.xml file is done using the TinyXML parser.
• Stack traces logged for selected trace points are generated by StackWalker.
• Efficient storage of execution traces is implemented using SQLite.