waterlovemelon / qt5printers

GDB Pretty printers for Qt5

qt5printers

The core.py, typeinfo.py and __init__.py files are taken from patchset 2 at https://codereview.qt-project.org/87052 and provide a GDB pretty printer for Qt5. These are authored by Alex Merry from the KDE project.

Usage

Copy the three Python files to ~/.gdb/qt5printers/ and add this to your ~/.gdbinit (or execute it from an existing gdb session):

python
import sys, os.path
sys.path.insert(0, os.path.expanduser('~/.gdb'))
import qt5printers
qt5printers.register_printers(gdb.current_objfile())
end

Now verify it with your favorite program. Below you can find a quick test program.

Test program

Here is a test program (save it as test.cpp):

#include <QTextStream>
void test(const QByteArray & ba) { }
int main(void) {
    test(QByteArray("abc"));
    return 0;
}

Compile it with:

g++ test.cpp $(pkg-config --cflags --libs Qt5Core) -g

If everything goes well you should see the expanded data:

$ gdb -q -ex break\ test -ex r ./a.out
...
Breakpoint 1, test (ba="abc" = {...}) at test.cpp:4
4           test(QByteArray("abc"));

Background

The Qt4 pretty printers from KDevelop0 are not fully compatible with Qt5. For instance, the latest version (from December 2014) does not properly handle QByteArray. While these qt5printers are compatible with Qt5, it conflicts with Qt4 (for example, QByteArray changed in Qt 5 from Qt 4 in this commit1).

See also:

• https://bugs.kde.org/show_bug.cgi?id=331044
• https://techbase.kde.org/Development/Tutorials/Debugging/Debugging_with_GDB

License

For the applicable licenses, see the headers of the files and refer to the Qt5 sources at https://code.qt.io/cgit/qt/qtbase.git/tree/.