Add _PyRuntime.imports.extensions.main_tstate.

python · ericsnowcurrently · Mar 29, 2023 · Mar 27, 2023 · Mar 21, 2023 · Mar 21, 2023
commit a86aea5b46d956efe68215ca91fb0320d116431c
@@ -15,6 +15,10 @@ struct _import_runtime_state {
        See PyInterpreterState.modules_by_index for more info. */
     Py_ssize_t last_module_index;
     struct {
+        /* A thread state tied to the main interpreter,
+           used exclusively for when the extensions dict is access/modified
+           from an arbitrary thread. */
+        PyThreadState main_tstate;
         /* A dict mapping (filename, name) to PyModuleDef for modules.
            Only legacy (single-phase init) extension modules are added
            and only if they support multiple initialization (m_size >- 0)

@@ -41,6 +41,11 @@ extern PyTypeObject _PyExc_MemoryError;
            in accordance with the specification. */ \
         .autoTSSkey = Py_tss_NEEDS_INIT, \
         .parser = _parser_runtime_state_INIT, \
+        .imports = { \
+            .extensions = { \
+                .main_tstate = _PyThreadState_INIT, \
+            }, \
+        }, \
         .ceval = { \
             .perf = _PyEval_RUNTIME_PERF_INIT, \
         }, \

@@ -890,6 +890,15 @@ extensions_lock_release(void)
    dictionary, to avoid loading shared libraries twice.
 */
 
+static void
+_extensions_cache_init(void)
+{
+    /* The runtime (i.e. main interpreter) must be initializing,
+       so we don't need to worry about the lock. */
+    _PyThreadState_InitDetached(&EXTENSIONS.main_tstate,
+                                _PyInterpreterState_Main());
+}
+
 static PyModuleDef *
 _extensions_cache_get(PyObject *filename, PyObject *name)
 {
@@ -981,6 +990,7 @@ _extensions_cache_clear_all(void)
        so we don't need to worry about the lock. */
     assert(_Py_IsMainInterpreter(_PyInterpreterState_GET()));
     Py_CLEAR(EXTENSIONS.dict);
+    _PyThreadState_ClearDetached(&EXTENSIONS.main_tstate);
 }
 
 
@@ -2979,6 +2989,10 @@ _PyImport_Fini2(void)
 PyStatus
 _PyImport_InitCore(PyThreadState *tstate, PyObject *sysmod, int importlib)
 {
+    if (_Py_IsMainInterpreter(tstate->interp)) {
+        _extensions_cache_init();
+    }
+
     // XXX Initialize here: interp->modules and interp->import_func.
     // XXX Initialize here: sys.modules and sys.meta_path.