wip

Author: kumaraditya303

Modules/_ctypes/_ctypes.c

@@ -717,7 +717,7 @@ StructUnionType_init(PyObject *self, PyObject *args, PyObject *kwds, int isStruc
         ret = PyCStgInfo_clone(info, baseinfo);
         if (ret >= 0) {
             assert(stginfo_get_dict_final(info) == 0);
-            stginfo_set_dict_final(baseinfo);
+            stginfo_set_dict_final_lock_held(baseinfo);
         }
         STGINFO_UNLOCK2();
         return ret;
@@ -3177,11 +3177,7 @@ PyCData_FromBaseObj(ctypes_state *st,
         return NULL;
     }
 
-    if (stginfo_get_dict_final(info) != 1) {
-        STGINFO_LOCK(info);
-        stginfo_set_dict_final(info);
-        STGINFO_UNLOCK();
-    }
+    stginfo_set_dict_final(info);
 
     assert(CDataObject_Check(st, cmem));
     cmem->b_length = info->length;
@@ -3226,11 +3222,8 @@ PyCData_AtAddress(ctypes_state *st, PyObject *type, void *buf)
                         "abstract class");
         return NULL;
     }
-    if (stginfo_get_dict_final(info) != 1) {
-        STGINFO_LOCK(info);
-        stginfo_set_dict_final(info);
-        STGINFO_UNLOCK();
-    }
+
+    stginfo_set_dict_final(info);
 
     pd = (CDataObject *)((PyTypeObject *)type)->tp_alloc((PyTypeObject *)type, 0);
     if (!pd) {
@@ -3464,11 +3457,8 @@ generic_pycdata_new(ctypes_state *st,
                         "abstract class");
         return NULL;
     }
-    if (stginfo_get_dict_final(info) != 1) {
-        STGINFO_LOCK(info);
-        stginfo_set_dict_final(info);
-        STGINFO_UNLOCK();
-    }
+
+    stginfo_set_dict_final(info);
 
     obj = (CDataObject *)type->tp_alloc(type, 0);
     if (!obj)

Modules/_ctypes/ctypes.h

@@ -411,20 +411,31 @@ typedef struct {
 #define STGINFO_UNLOCK()        Py_END_CRITICAL_SECTION()
 #define STGINFO_UNLOCK2()       Py_END_CRITICAL_SECTION2()
 
+static inline int
+stginfo_get_dict_final(StgInfo *info)
+{
+    return FT_ATOMIC_LOAD_INT(info->dict_final);
+}
+
 static inline void
-stginfo_set_dict_final(StgInfo *info)
+stginfo_set_dict_final_lock_held(StgInfo *info)
 {
     _Py_CRITICAL_SECTION_ASSERT_MUTEX_LOCKED(&info->mutex);
     FT_ATOMIC_STORE_INT(info->dict_final, 1);
 }
 
-static inline int
-stginfo_get_dict_final(StgInfo *info)
+static inline void
+stginfo_set_dict_final(StgInfo *info)
 {
-    return FT_ATOMIC_LOAD_INT(info->dict_final);
+    // avoid acquiring the lock if final is already set
+    if (stginfo_get_dict_final(info) == 1) {
+        return;
+    }
+    STGINFO_LOCK(info);
+    stginfo_set_dict_final_lock_held(info);
+    STGINFO_UNLOCK();
 }
 
-
 extern int PyCStgInfo_clone(StgInfo *dst_info, StgInfo *src_info);
 extern void ctype_clear_stginfo(StgInfo *info);
 

Modules/_ctypes/stgdict.c

@@ -436,7 +436,7 @@ PyCStructUnionType_update_stginfo(PyObject *type, PyObject *fields, int isStruct
         if (info->flags & (TYPEFLAG_ISPOINTER | TYPEFLAG_HASPOINTER))
             stginfo->flags |= TYPEFLAG_HASPOINTER;
 
-        stginfo_set_dict_final(info); /* mark field type final */
+        stginfo_set_dict_final_lock_held(info); /* mark field type final */
         STGINFO_UNLOCK();
         if (-1 == PyObject_SetAttr(type, prop->name, prop_obj)) {
             goto error;
@@ -476,7 +476,7 @@ PyCStructUnionType_update_stginfo(PyObject *type, PyObject *fields, int isStruct
                         "Structure or union cannot contain itself");
         goto error;
     }
-    stginfo_set_dict_final(stginfo);
+    stginfo_set_dict_final_lock_held(stginfo);
 
     retval = MakeAnonFields(type);
 error:;