Expose tracemalloc hook into `_Py_NewReference` for other tracers

When new objects are created, the allocation code ends calling into _Py_NewReference (with some exceptions). tracemalloc has a hook into this function to correlate allocations and traces (that do not know anything about objects or references) with newly created objects. This happens here:

https://github.com/python/cpython/blob/3d647e70cf4fd0e7cef68ed6662de3cb2cb0d63d/Objects/object.c#L2018-L2020

This allows tracemalloc to be able to return the traceback where objects where allocated, which is great. Unfortunately other debuggers and profilers do not have this capability as there is no way to leverage trace malloc functionality or to hook into object creation.

I propose to expose an API (unclear what layer of the C-API this should be in) where callbacks can be registered to be called in _Py_NewReference and switch tracemalloc to use this API.

Linked PRs

• gh-115945

Objects/object.c の _Py_NewReference 呼び出し付近から始め、現在 tracemalloc がそこにどのようにフックしているかを確認してください。適切な API 層を決定する前に、リンクされている PR gh-115945 と、その周辺の C-API に関する議論を読んでください。他の tracer が callback を登録でき、tracemalloc が allocation trace の相関を失わずにその API を使用できれば完了です。