Description
Feature or enhancement
An API similar to:
/* Visit all live GC-capable objects, similar to gc.get_objects(None).
*
* Users should avoid allocating or deallocating objects on the Python heap in
* the callback. */
typedef void (*gcvisitobjects_t)(PyObject *, void *);
PyAPI_FUNC(void) PyGC_VisitObjects(gcvisitobjects_t callback, void *arg);
Which could be used as:
void count_functions(PyObject *op, void *arg) {
if (PyFunction_Check(op)) {
(*(int*)arg)++;
}
}
int get_num_functions() {
int count;
PyGC_VisitObjects(count_functions, &count);
return count;
}
Pitch
We have a version of this in Cinder already and right now and use it to identify all generator objects so they can be de-opted when our JIT is shutdown. In future we plan to use it for things like discovering existing PyFunction objects, and then using gh-91049 to mark them as JIT’able. This could facilitate loading the JIT feature at a later time (e.g. as part of a module).
[Edited] In general, there already exists a Python API for iterating over GC’able objects via gc.get_objects(), however there is no good way of doing this from native extensions. While it is technically possible to import the gc module and extract the gc_objects function in C this is cumbersome, and more importantly might lead to unexpected behavior if Python code has replaced the gc_objects function.