python: Use PyBind11 instead of SWIG for Python wrappers
Review Request #3827 - Created Feb. 21, 2017 and discarded
Changeset 11884:e0f1c63a8440 --------------------------- python: Use PyBind11 instead of SWIG for Python wrappers Use the PyBind11 wrapping infrastructure instead of SWIG to generate wrappers for functionality that needs to be exported to Python. This has several benefits: * PyBind11 can be redistributed with gem5, which means that we have full control of the version used. This avoid a large number of hard-to-debug SWIG issues we have seen in the past. * PyBind11 doesn't rely on a custom C++ parser, instead it relies on wrappers being explicitly declared in C++. The leads to slightly more boiler-plate code in manually created wrappers, but doesn't doesn't increase the overall code size. A big benefit is that this avoids strange compilation errors when SWIG doesn't understand modern language features. * Unlike SWIG, there is no risk that the wrapper code incorporates incorrect type casts (this has happened on numerous occasions in the past) since these will result in compile-time errors. As a part of this change, the mechanism to define exported methods has been redesigned slightly. New methods can be exported either by declaring them in the SimObject declaration and decorating them with the cxxMethod decorator or by adding an instance of PyBindMethod/PyBindProperty to the cxx_exports class variable. The decorator has the added benefit of making it possible to add a docstring and naming the method's parameters. The new wrappers has the following known issues: * Global events can't be memory managed correctly. This was the case in SWIG as well. Change-Id: I88c5a95b6cf6c32fa9e1ad31dfc08b2e8199a763 Signed-off-by: Andreas Sandberg <email@example.com> Reviewed-by: Andreas Hansson <firstname.lastname@example.org> Reviewed-by: Andrew Bardsley <email@example.com>
NOTE: I have few cleanup patches that remove SWIG-related stuff from the build system and the C++ files. These will be submitted separately if this gets approved.
This seems like a welcome change. A question: are there any requirements for using PyBind besides Python 2.7 or 3.x and the std clibs? I see that the PyBind GitHub only mentions these dependencies, and I wanted to get confirmation based on your experiences using it.
Revision 2 (+1501 -1660)