gh-94673: More Per-Interpreter Fields for Builtin Static Types (gh-103912)

his involves moving tp_dict, tp_bases, and tp_mro to PyInterpreterState, in the same way we did for tp_subclasses.  Those three fields are effectively const for builtin static types (unlike tp_subclasses).  In theory we only need to make their values immortal, along with their contents.  However, that isn't such a simple proposition.  (See gh-103823.)  In the meantime the simplest solution is to move the fields into the interpreter.

One alternative is to statically allocate the values, but that's its own can of worms.

1 files changed, 3 insertions, 28 deletions

diff --git a/Modules/gcmodule.c b/Modules/gcmodule.c
index 8a4d1a4..f4d5186 100644
--- a/Modules/gcmodule.c
+++ b/Modules/gcmodule.c
@@ -2174,23 +2174,6 @@ _PyGC_DumpShutdownStats(PyInterpreterState *interp)
 }
 
 
-static void
-gc_fini_untrack(PyGC_Head *list)
-{
-    PyGC_Head *gc;
-    for (gc = GC_NEXT(list); gc != list; gc = GC_NEXT(list)) {
-        PyObject *op = FROM_GC(gc);
-        _PyObject_GC_UNTRACK(op);
-        // gh-92036: If a deallocator function expect the object to be tracked
-        // by the GC (ex: func_dealloc()), it can crash if called on an object
-        // which is no longer tracked by the GC. Leak one strong reference on
-        // purpose so the object is never deleted and its deallocator is not
-        // called.
-        Py_INCREF(op);
-    }
-}
-
-
 void
 _PyGC_Fini(PyInterpreterState *interp)
 {
@@ -2198,17 +2181,9 @@ _PyGC_Fini(PyInterpreterState *interp)
     Py_CLEAR(gcstate->garbage);
     Py_CLEAR(gcstate->callbacks);
 
-    if (!_Py_IsMainInterpreter(interp)) {
-        // bpo-46070: Explicitly untrack all objects currently tracked by the
-        // GC. Otherwise, if an object is used later by another interpreter,
-        // calling PyObject_GC_UnTrack() on the object crashs if the previous
-        // or the next object of the PyGC_Head structure became a dangling
-        // pointer.
-        for (int i = 0; i < NUM_GENERATIONS; i++) {
-            PyGC_Head *gen = GEN_HEAD(gcstate, i);
-            gc_fini_untrack(gen);
-        }
-    }
+    /* We expect that none of this interpreters objects are shared
+       with other interpreters.
+       See https://github.com/python/cpython/issues/90228. */
 }
 
 /* for debugging */