Add test for exit

Author: Fidget-Spinner

Lib/test/test_capi/test_opt.py

@@ -60,6 +60,13 @@ def iter_opnames(ex):
 def get_opnames(ex):
     return list(iter_opnames(ex))
 
+def iter_ops(ex):
+    for item in ex:
+        yield item
+
+def get_ops(ex):
+    return list(iter_ops(ex))
+
 
 @requires_specialization
 @unittest.skipIf(Py_GIL_DISABLED, "optimizer not yet supported in free-threaded builds")
@@ -3003,14 +3010,22 @@ def f():
         # Outer loop warms up later, linking to the inner one.
         # Therefore, we have at least two executors.
         self.assertGreaterEqual(len(all_executors), 2)
+        executor_ids = [id(e) for e in all_executors]
         for executor in all_executors:
-            opnames = list(get_opnames(executor))
+            ops = list(get_ops(executor))
             # Assert all executors first terminator ends in
             # _EXIT_TRACE or _JUMP_TO_TOP, not _DEOPT
-            for idx, op in enumerate(opnames):
-                if op == "_EXIT_TRACE" or op == "_JUMP_TO_TOP":
+            for idx, op in enumerate(ops):
+                opname = op[0]
+                if opname == "_EXIT_TRACE":
+                    # All executors exits should point to another valid executor
+                    exit = op[3]
+                    link_to = _testinternalcapi.get_exit_executor(exit)
+                    self.assertIn(id(link_to), executor_ids)
+                    break
+                elif opname == "_JUMP_TO_TOP":
                     break
-                elif op == "_DEOPT":
+                elif opname == "_DEOPT":
                     self.fail(f"_DEOPT encountered first at executor"
                               f" {executor} at offset {idx} rather"
                               f" than expected _EXIT_TRACE")

Modules/_testinternalcapi.c

@@ -1245,6 +1245,22 @@ invalidate_executors(PyObject *self, PyObject *obj)
     Py_RETURN_NONE;
 }
 
+static PyObject *
+get_exit_executor(PyObject *self, PyObject *arg)
+{
+    if (!PyLong_CheckExact(arg)) {
+        PyErr_SetString(PyExc_TypeError, "argument must be an ID to an _PyExitData");
+        return NULL;
+    }
+    uint64_t ptr;
+    if (PyLong_AsUInt64(arg, &ptr) < 0) {
+        // Error set by PyLong API
+        return NULL;
+    }
+    _PyExitData *exit = (_PyExitData *)ptr;
+    return Py_NewRef(exit->executor);
+}
+
 #endif
 
 static int _pending_callback(void *arg)
@@ -2546,6 +2562,7 @@ static PyMethodDef module_functions[] = {
 #ifdef _Py_TIER2
     {"add_executor_dependency", add_executor_dependency, METH_VARARGS, NULL},
     {"invalidate_executors", invalidate_executors, METH_O, NULL},
+    {"get_exit_executor", get_exit_executor, METH_O, NULL},
 #endif
     {"pending_threadfunc", _PyCFunction_CAST(pending_threadfunc),
      METH_VARARGS | METH_KEYWORDS},