What’s new in PyPy2.7 5.10+

Big refactoring of some cpyext code, which avoids a lot of nonsense when calling C from Python and vice-versa: the result is a big speedup in function/method calls, up to 6 times faster.

Support tzinfo field on C-API datetime objects, fixes latest pandas HEAD

Fix a corner case of mapdict: When an instance is used like a dict (using setattr and getattr, or .__dict__) and a lot of attributes are added, then the performance using mapdict is linear in the number of attributes. This is now fixed (by switching to a regular dict after 80 attributes).

When using cpyext, improve the speed of passing certain objects from PyPy to C code, most notably None, True, False, types, all instances of C-defined types. Before, a dict lookup was needed every time such an object crossed over, now it is just a field read.

Improve datetime + timedelta performance.

Improve way to describe memory

Allow compilaiton with Visual Studio 2017 compiler suite on windows

Refactor cpyext slots.