bpo-39877: _PyRuntimeState.finalizing becomes atomic (GH-18816)

Convert _PyRuntimeState.finalizing field to an atomic variable:

* Rename it to _finalizing
* Change its type to _Py_atomic_address
* Add _PyRuntimeState_GetFinalizing() and _PyRuntimeState_SetFinalizing()
  functions
* Remove _Py_CURRENTLY_FINALIZING() function: replace it with testing
  directly _PyRuntimeState_GetFinalizing() value

Convert _PyRuntimeState_GetThreadState() to static inline function.

1 files changed, 17 insertions, 6 deletions

diff --git a/Include/internal/pycore_pystate.h b/Include/internal/pycore_pystate.h
index 405efb9..b5f5095 100644
--- a/Include/internal/pycore_pystate.h
+++ b/Include/internal/pycore_pystate.h
@@ -223,8 +223,11 @@ typedef struct pyruntimestate {
     int initialized;
 
     /* Set by Py_FinalizeEx(). Only reset to NULL if Py_Initialize()
-       is called again. */
-    PyThreadState *finalizing;
+       is called again.
+
+       Use _PyRuntimeState_GetFinalizing() and _PyRuntimeState_SetFinalizing()
+       to access it, don't access it directly. */
+    _Py_atomic_address _finalizing;
 
     struct pyinterpreters {
         PyThread_type_lock mutex;
@@ -279,8 +282,15 @@ PyAPI_FUNC(PyStatus) _PyRuntime_Initialize(void);
 
 PyAPI_FUNC(void) _PyRuntime_Finalize(void);
 
-#define _Py_CURRENTLY_FINALIZING(runtime, tstate) \
-    (runtime->finalizing == tstate)
+static inline PyThreadState*
+_PyRuntimeState_GetFinalizing(_PyRuntimeState *runtime) {
+    return (PyThreadState*)_Py_atomic_load_relaxed(&runtime->_finalizing);
+}
+
+static inline void
+_PyRuntimeState_SetFinalizing(_PyRuntimeState *runtime, PyThreadState *tstate) {
+    _Py_atomic_store_relaxed(&runtime->_finalizing, (uintptr_t)tstate);
+}
 
 PyAPI_FUNC(int) _Py_IsMainInterpreter(PyThreadState* tstate);
 
@@ -288,8 +298,9 @@ PyAPI_FUNC(int) _Py_IsMainInterpreter(PyThreadState* tstate);
 /* Variable and macro for in-line access to current thread
    and interpreter state */
 
-#define _PyRuntimeState_GetThreadState(runtime) \
-    ((PyThreadState*)_Py_atomic_load_relaxed(&(runtime)->gilstate.tstate_current))
+static inline PyThreadState* _PyRuntimeState_GetThreadState(_PyRuntimeState *runtime) {
+    return (PyThreadState*)_Py_atomic_load_relaxed(&runtime->gilstate.tstate_current);
+}
 
 /* Get the current Python thread state.