Mathutils types were always GC tracked even when it wasn't intended.
Not having to track objects speeds up Python execution.
In an isolated benchmark created to stress test the GC
creating 4-million vectors (re-assigning them 100 times), this gives
an overall ~2.5x speedup, see: P3221.
Details:
Since [0] (which added support for sub-classed mathutils types)
tp_alloc was called which defaults to PyType_GenericAlloc which always
GC tracked the resulting object when Py_TPFLAGS_HAVE_GC was set.
Avoid using PyType_GenericAlloc unless the type is sub-classed,
in that case the object is un-tracked.
Add asserts that the tracked state is as expected before tracking &
un-tracking, to ensure changes to object creation don't cause objects
to be tracked unintentionally.
Also assign the PyTypeObject.tp_is_gc callback so types optionally GC
track objects only do so when an object is referenced.
[0]: fbd9364944
Use a shorter/simpler license convention, stops the header taking so
much space.
Follow the SPDX license specification: https://spdx.org/licenses
- C/C++/objc/objc++
- Python
- Shell Scripts
- CMake, GNUmakefile
While most of the source tree has been included
- `./extern/` was left out.
- `./intern/cycles` & `./intern/atomic` are also excluded because they
use different header conventions.
doc/license/SPDX-license-identifiers.txt has been added to list SPDX all
used identifiers.
See P2788 for the script that automated these edits.
Reviewed By: brecht, mont29, sergey
Ref D14069
