# 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.

Speed up branchy code that does a lot of function inlining by saving one call to read the TLS in most bridges.

Refactor in rpython signatures

Store error state thread-locally in executioncontext, fixes issue #2764

Optimize Py*_Check for Bool, Float, Set. Also refactor and simplify W_PyCWrapperObject which is used to call slots from the C-API, greatly improving microbenchmarks in https://github.com/antocuni/cpyext-benchmarks

Fix two (unrelated) JIT bugs manifesting in the re module:

- green fields are broken and were thus disabled, plus their usage removed from the _sre implementation

- in rare "trace is too long" situations, the JIT could break behaviour arbitrarily.

Be more efficient about JIT hooks. Make it possible for the frontend to declare that jit hooks are currently not enabled at all. in that case, the list of ops does not have to be created in the case of the on_abort hook (which is expensive).

Improve speed of Python parser, improve ParseError messages slightly.

Work around possible bugs in upstream ioctl users, like CPython allocate at least 1024 bytes for the arg in calls to `ioctl(fd, request, arg)`. Fixes issue #2776

Fix for python-level classes that inherit from C-API types, previously the w_obj was not necessarily preserved throughout the lifetime of the pyobj which led to cases where instance attributes were lost. Fixes issue #2793

Improve line offsets that are reported by SyntaxError. Improve error messages for a few situations, including mismatched parenthesis.

Fix a rare GC bug that was introduced more than one year ago, but was not diagnosed before issue #2752.

Introduce GC hooks, as documented in doc/gc_info.rst

Improve GC hooks

Update backend to 0.6.0 and support exceptions through wrappers