gh-115999: Enable specialization of `CALL` instructions in free-threaded builds (#127123)

The CALL family of instructions were mostly thread-safe already and only required a small number of changes, which are documented below.

A few changes were needed to make CALL_ALLOC_AND_ENTER_INIT thread-safe:

Added _PyType_LookupRefAndVersion, which returns the type version corresponding to the returned ref.

Added _PyType_CacheInitForSpecialization, which takes an init method and the corresponding type version and only populates the specialization cache if the current type version matches the supplied version. This prevents potentially caching a stale value in free-threaded builds if we race with an update to __init__.

Only cache __init__ functions that are deferred in free-threaded builds. This ensures that the reference to __init__ that is stored in the specialization cache is valid if the type version guard in _CHECK_AND_ALLOCATE_OBJECT passes.
Fix a bug in _CREATE_INIT_FRAME where the frame is pushed to the stack on failure.

A few other miscellaneous changes were also needed:

Use {LOCK,UNLOCK}_OBJECT in LIST_APPEND. This ensures that the list's per-object lock is held while we are appending to it.

Add missing co_tlbc for _Py_InitCleanup.

Stop/start the world around setting the eval frame hook. This allows us to read interp->eval_frame non-atomically and preserves the behavior of _CHECK_PEP_523 documented below.

1 files changed, 2 insertions, 0 deletions

diff --git a/Python/pystate.c b/Python/pystate.c
index 3ceae229f75..839413a65a4 100644
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -2838,7 +2838,9 @@ _PyInterpreterState_SetEvalFrameFunc(PyInterpreterState *interp,
     }
 #endif
     RARE_EVENT_INC(set_eval_frame_func);
+    _PyEval_StopTheWorld(interp);
     interp->eval_frame = eval_frame;
+    _PyEval_StartTheWorld(interp);
 }