Attached is a patch that adds a few features to the Python debugging support for gdb:

- listing of globals
- python breakpoints
- python stepping/stepping over/finishing of frames/running/continuing
- python code execution in the most recent Python frame (relative to the selected frame)

Unit tests are included in Lib/test/test_gdb.py. It should be compatible with both python 3 and python 2 (this is important because libpython.py is also part of the Cython debugger branch, see https://github.com/markflorisson88/cython/blob/master/Cython/Debugger/libpython.py ). Python 2 tests are in that Cython branch.

It would be great if libpython.py could be installed as an actual Python  module instead of a tool, where 'python-gdb.py' would be the actual tool that imports libpython.py. This may remove the need in the future to duplicate files in the Python source distribution and in future versions of Cython. Another good thing about that is that if users don't have python-gdb.py installed properly, or would like to use functionality without having loaded the interpreter in gdb (i.e. 'file python'), they can just do 'python import libpython' in gdb to load the Python support.

I can't assign this issue, but Dave Malcolm (dmalcolm) asked me to assign the issue to him, so I kindly request someone with these capabilities to assign this issue accordingly.