From 9c87ae156ba7923a0d079dc8f9afbc3b4eabc8db Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Mon, 20 Jan 2025 14:41:35 +0100
Subject: [PATCH 01/13] fix UBSan failures for `DictRemoverObject`

---
 Modules/_ctypes/_ctypes.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
index c4d130a5ec1d52..3906ace92daee2 100644
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -146,9 +146,12 @@ typedef struct {
     PyObject *dict;
 } DictRemoverObject;
 
+#define _DictRemoverObject_CAST(op)     ((DictRemoverObject *)(op))
+
 static int
-_DictRemover_traverse(DictRemoverObject *self, visitproc visit, void *arg)
+_DictRemover_traverse(PyObject *myself, visitproc visit, void *arg)
 {
+    DictRemoverObject *self = _DictRemoverObject_CAST(myself);
     Py_VISIT(Py_TYPE(self));
     Py_VISIT(self->key);
     Py_VISIT(self->dict);
@@ -156,8 +159,9 @@ _DictRemover_traverse(DictRemoverObject *self, visitproc visit, void *arg)
 }
 
 static int
-_DictRemover_clear(DictRemoverObject *self)
+_DictRemover_clear(PyObject *myself)
 {
+    DictRemoverObject *self = _DictRemoverObject_CAST(myself);
     Py_CLEAR(self->key);
     Py_CLEAR(self->dict);
     return 0;
@@ -167,7 +171,7 @@ static void
 _DictRemover_dealloc(PyObject *myself)
 {
     PyTypeObject *tp = Py_TYPE(myself);
-    DictRemoverObject *self = (DictRemoverObject *)myself;
+    DictRemoverObject *self = _DictRemoverObject_CAST(myself);
     PyObject_GC_UnTrack(myself);
     (void)_DictRemover_clear(self);
     tp->tp_free(myself);
@@ -177,7 +181,7 @@ _DictRemover_dealloc(PyObject *myself)
 static PyObject *
 _DictRemover_call(PyObject *myself, PyObject *args, PyObject *kw)
 {
-    DictRemoverObject *self = (DictRemoverObject *)myself;
+    DictRemoverObject *self = _DictRemoverObject_CAST(myself);
     if (self->key && self->dict) {
         if (-1 == PyDict_DelItem(self->dict, self->key)) {
             PyErr_FormatUnraisable("Exception ignored on calling _ctypes.DictRemover");

From ec730bab0ee84415be8151c026a159c14aa71d3e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Mon, 20 Jan 2025 14:41:42 +0100
Subject: [PATCH 02/13] fix UBSan failures for `StructParamObject`

---
 Modules/_ctypes/_ctypes.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
index 3906ace92daee2..23307c8f079596 100644
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -406,16 +406,19 @@ typedef struct {
     PyObject *keep;  // If set, a reference to the original CDataObject.
 } StructParamObject;
 
+#define _StructParamObject_CAST(op) ((StructParamObject *)(op))
+
 static int
-StructParam_traverse(StructParamObject *self, visitproc visit, void *arg)
+StructParam_traverse(PyObject *self, visitproc visit, void *arg)
 {
     Py_VISIT(Py_TYPE(self));
     return 0;
 }
 
 static int
-StructParam_clear(StructParamObject *self)
+StructParam_clear(PyObject *op)
 {
+    StructParamObject *self = _StructParamObject_CAST(op);
     Py_CLEAR(self->keep);
     return 0;
 }
@@ -423,7 +426,7 @@ StructParam_clear(StructParamObject *self)
 static void
 StructParam_dealloc(PyObject *myself)
 {
-    StructParamObject *self = (StructParamObject *)myself;
+    StructParamObject *self = _StructParamObject_CAST(myself);
     PyTypeObject *tp = Py_TYPE(self);
     PyObject_GC_UnTrack(myself);
     (void)StructParam_clear(self);

From a604eb7d1189ca5957572435cd8f1c33d7d4c9b2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Mon, 20 Jan 2025 14:53:15 +0100
Subject: [PATCH 03/13] fix UBSan failures for `CDataObject`

---
 Modules/_ctypes/_ctypes.c | 136 ++++++++++++++++++++------------------
 1 file changed, 72 insertions(+), 64 deletions(-)

diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
index 23307c8f079596..4d04710a099c9d 100644
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -1417,12 +1417,15 @@ static PyType_Spec pycpointer_type_spec = {
   attribute, and a _type_ attribute.
 */
 
+#define _CDataObject_CAST(op)   ((CDataObject *)(op))
+
 static int
-CharArray_set_raw(CDataObject *self, PyObject *value, void *Py_UNUSED(ignored))
+CharArray_set_raw(PyObject *op, PyObject *value, void *Py_UNUSED(ignored))
 {
     char *ptr;
     Py_ssize_t size;
     Py_buffer view;
+    CDataObject *self = _CDataObject_CAST(op);
 
     if (value == NULL) {
         PyErr_SetString(PyExc_AttributeError, "cannot delete attribute");
@@ -1448,9 +1451,10 @@ CharArray_set_raw(CDataObject *self, PyObject *value, void *Py_UNUSED(ignored))
 }
 
 static PyObject *
-CharArray_get_raw(CDataObject *self, void *Py_UNUSED(ignored))
+CharArray_get_raw(PyObject *op, void *Py_UNUSED(ignored))
 {
     PyObject *res;
+    CDataObject *self = _CDataObject_CAST(op);
     LOCK_PTR(self);
     res = PyBytes_FromStringAndSize(self->b_ptr, self->b_size);
     UNLOCK_PTR(self);
@@ -1458,10 +1462,11 @@ CharArray_get_raw(CDataObject *self, void *Py_UNUSED(ignored))
 }
 
 static PyObject *
-CharArray_get_value(CDataObject *self, void *Py_UNUSED(ignored))
+CharArray_get_value(PyObject *op, void *Py_UNUSED(ignored))
 {
     Py_ssize_t i;
     PyObject *res;
+    CDataObject *self = _CDataObject_CAST(op);
     LOCK_PTR(self);
     char *ptr = self->b_ptr;
     for (i = 0; i < self->b_size; ++i)
@@ -1473,10 +1478,11 @@ CharArray_get_value(CDataObject *self, void *Py_UNUSED(ignored))
 }
 
 static int
-CharArray_set_value(CDataObject *self, PyObject *value, void *Py_UNUSED(ignored))
+CharArray_set_value(PyObject *op, PyObject *value, void *Py_UNUSED(ignored))
 {
     const char *ptr;
     Py_ssize_t size;
+    CDataObject *self = _CDataObject_CAST(op);
 
     if (value == NULL) {
         PyErr_SetString(PyExc_TypeError,
@@ -1511,18 +1517,17 @@ CharArray_set_value(CDataObject *self, PyObject *value, void *Py_UNUSED(ignored)
 }
 
 static PyGetSetDef CharArray_getsets[] = {
-    { "raw", (getter)CharArray_get_raw, (setter)CharArray_set_raw,
-      "value", NULL },
-    { "value", (getter)CharArray_get_value, (setter)CharArray_set_value,
-      "string value"},
+    { "raw", CharArray_get_raw, CharArray_set_raw, "value", NULL },
+    { "value", CharArray_get_value, CharArray_set_value, "string value" },
     { NULL, NULL }
 };
 
 static PyObject *
-WCharArray_get_value(CDataObject *self, void *Py_UNUSED(ignored))
+WCharArray_get_value(PyObject *op, void *Py_UNUSED(ignored))
 {
     Py_ssize_t i;
     PyObject *res;
+    CDataObject *self = _CDataObject_CAST(op);
     wchar_t *ptr = (wchar_t *)self->b_ptr;
     LOCK_PTR(self);
     for (i = 0; i < self->b_size/(Py_ssize_t)sizeof(wchar_t); ++i)
@@ -1534,8 +1539,10 @@ WCharArray_get_value(CDataObject *self, void *Py_UNUSED(ignored))
 }
 
 static int
-WCharArray_set_value(CDataObject *self, PyObject *value, void *Py_UNUSED(ignored))
+WCharArray_set_value(PyObject *op, PyObject *value, void *Py_UNUSED(ignored))
 {
+    CDataObject *self = _CDataObject_CAST(op);
+
     if (value == NULL) {
         PyErr_SetString(PyExc_TypeError,
                         "can't delete attribute");
@@ -1568,8 +1575,7 @@ WCharArray_set_value(CDataObject *self, PyObject *value, void *Py_UNUSED(ignored
 }
 
 static PyGetSetDef WCharArray_getsets[] = {
-    { "value", (getter)WCharArray_get_value, (setter)WCharArray_set_value,
-      "string value"},
+    { "value", WCharArray_get_value, WCharArray_set_value, "string value" },
     { NULL, NULL }
 };
 
@@ -2893,8 +2899,9 @@ class _ctypes.PyCData "PyObject *" "clinic_state()->PyCData_Type"
 
 
 static int
-PyCData_traverse(CDataObject *self, visitproc visit, void *arg)
+PyCData_traverse(PyObject *op, visitproc visit, void *arg)
 {
+    CDataObject *self = _CDataObject_CAST(op);
     Py_VISIT(self->b_objects);
     Py_VISIT((PyObject *)self->b_base);
     PyTypeObject *type = Py_TYPE(self);
@@ -2903,8 +2910,9 @@ PyCData_traverse(CDataObject *self, visitproc visit, void *arg)
 }
 
 static int
-PyCData_clear(CDataObject *self)
+PyCData_clear(PyObject *op)
 {
+    CDataObject *self = _CDataObject_CAST(op);
     Py_CLEAR(self->b_objects);
     if ((self->b_needsfree)
         && _CDataObject_HasExternalBuffer(self))
@@ -2919,7 +2927,7 @@ PyCData_dealloc(PyObject *self)
 {
     PyTypeObject *type = Py_TYPE(self);
     PyObject_GC_UnTrack(self);
-    PyCData_clear((CDataObject *)self);
+    (void)PyCData_clear(self);
     type->tp_free(self);
     Py_DECREF(type);
 }
@@ -2962,7 +2970,7 @@ PyCData_item_type(ctypes_state *st, PyObject *type)
 static int
 PyCData_NewGetBuffer(PyObject *myself, Py_buffer *view, int flags)
 {
-    CDataObject *self = (CDataObject *)myself;
+    CDataObject *self = _CDataObject_CAST(myself);
 
     ctypes_state *st = get_module_state_by_def(Py_TYPE(Py_TYPE(myself)));
     StgInfo *info;
@@ -3021,7 +3029,7 @@ static PyObject *
 PyCData_reduce_impl(PyObject *myself, PyTypeObject *cls)
 /*[clinic end generated code: output=1a025ccfdd8c935d input=34097a5226ea63c1]*/
 {
-    CDataObject *self = (CDataObject *)myself;
+    CDataObject *self = _CDataObject_CAST(myself);
 
     ctypes_state *st = get_module_state_by_class(cls);
     StgInfo *info;
@@ -3054,7 +3062,7 @@ PyCData_setstate(PyObject *myself, PyObject *args)
     Py_ssize_t len;
     int res;
     PyObject *dict, *mydict;
-    CDataObject *self = (CDataObject *)myself;
+    CDataObject *self = _CDataObject_CAST(myself);
     if (!PyArg_ParseTuple(args, "O!s#",
                           &PyDict_Type, &dict, &data, &len))
     {
@@ -4790,7 +4798,7 @@ static PyType_Spec pycunion_spec = {
   PyCArray_Type
 */
 static int
-Array_init(CDataObject *self, PyObject *args, PyObject *kw)
+Array_init(PyObject *self, PyObject *args, PyObject *kw)
 {
     Py_ssize_t i;
     Py_ssize_t n;
@@ -4804,7 +4812,7 @@ Array_init(CDataObject *self, PyObject *args, PyObject *kw)
     for (i = 0; i < n; ++i) {
         PyObject *v;
         v = PyTuple_GET_ITEM(args, i);
-        if (-1 == PySequence_SetItem((PyObject *)self, i, v))
+        if (-1 == PySequence_SetItem(self, i, v))
             return -1;
     }
     return 0;
@@ -4813,8 +4821,8 @@ Array_init(CDataObject *self, PyObject *args, PyObject *kw)
 static PyObject *
 Array_item(PyObject *myself, Py_ssize_t index)
 {
-    CDataObject *self = (CDataObject *)myself;
     Py_ssize_t offset, size;
+    CDataObject *self = _CDataObject_CAST(myself);
 
     if (index < 0 || index >= self->b_length) {
         PyErr_SetString(PyExc_IndexError,
@@ -4824,7 +4832,7 @@ Array_item(PyObject *myself, Py_ssize_t index)
 
     ctypes_state *st = get_module_state_by_def(Py_TYPE(Py_TYPE(self)));
     StgInfo *stginfo;
-    if (PyStgInfo_FromObject(st, (PyObject *)self, &stginfo) < 0) {
+    if (PyStgInfo_FromObject(st, myself, &stginfo) < 0) {
         return NULL;
     }
 
@@ -4834,14 +4842,14 @@ Array_item(PyObject *myself, Py_ssize_t index)
     size = stginfo->size / stginfo->length;
     offset = index * size;
 
-    return PyCData_get(st, stginfo->proto, stginfo->getfunc, (PyObject *)self,
-                     index, size, self->b_ptr + offset);
+    return PyCData_get(st, stginfo->proto, stginfo->getfunc, myself,
+                       index, size, self->b_ptr + offset);
 }
 
 static PyObject *
 Array_subscript(PyObject *myself, PyObject *item)
 {
-    CDataObject *self = (CDataObject *)myself;
+    CDataObject *self = _CDataObject_CAST(myself);
 
     if (PyIndex_Check(item)) {
         Py_ssize_t i = PyNumber_AsSsize_t(item, PyExc_IndexError);
@@ -4865,7 +4873,7 @@ Array_subscript(PyObject *myself, PyObject *item)
 
         ctypes_state *st = get_module_state_by_def(Py_TYPE(Py_TYPE(self)));
         StgInfo *stginfo;
-        if (PyStgInfo_FromObject(st, (PyObject *)self, &stginfo) < 0) {
+        if (PyStgInfo_FromObject(st, myself, &stginfo) < 0) {
             return NULL;
         }
         assert(stginfo); /* Cannot be NULL for array object instances */
@@ -4966,7 +4974,7 @@ Array_subscript(PyObject *myself, PyObject *item)
 static int
 Array_ass_item(PyObject *myself, Py_ssize_t index, PyObject *value)
 {
-    CDataObject *self = (CDataObject *)myself;
+    CDataObject *self = _CDataObject_CAST(myself);
     Py_ssize_t size, offset;
     char *ptr;
 
@@ -4978,7 +4986,7 @@ Array_ass_item(PyObject *myself, Py_ssize_t index, PyObject *value)
 
     ctypes_state *st = get_module_state_by_def(Py_TYPE(Py_TYPE(self)));
     StgInfo *stginfo;
-    if (PyStgInfo_FromObject(st, (PyObject *)self, &stginfo) < 0) {
+    if (PyStgInfo_FromObject(st, myself, &stginfo) < 0) {
         return -1;
     }
     assert(stginfo); /* Cannot be NULL for array object instances */
@@ -4992,14 +5000,14 @@ Array_ass_item(PyObject *myself, Py_ssize_t index, PyObject *value)
     offset = index * size;
     ptr = self->b_ptr + offset;
 
-    return PyCData_set(st, (PyObject *)self, stginfo->proto, stginfo->setfunc, value,
-                     index, size, ptr);
+    return PyCData_set(st, myself, stginfo->proto, stginfo->setfunc, value,
+                       index, size, ptr);
 }
 
 static int
 Array_ass_subscript(PyObject *myself, PyObject *item, PyObject *value)
 {
-    CDataObject *self = (CDataObject *)myself;
+    CDataObject *self = _CDataObject_CAST(myself);
 
     if (value == NULL) {
         PyErr_SetString(PyExc_TypeError,
@@ -5056,7 +5064,7 @@ Array_ass_subscript(PyObject *myself, PyObject *item, PyObject *value)
 static Py_ssize_t
 Array_length(PyObject *myself)
 {
-    CDataObject *self = (CDataObject *)myself;
+    CDataObject *self = _CDataObject_CAST(myself);
     return self->b_length;
 }
 
@@ -5173,9 +5181,10 @@ class _ctypes.Simple "PyObject *" "clinic_state()->Simple_Type"
 /*[clinic end generated code: output=da39a3ee5e6b4b0d input=016c476c7aa8b8a8]*/
 
 static int
-Simple_set_value(CDataObject *self, PyObject *value, void *Py_UNUSED(ignored))
+Simple_set_value(PyObject *myself, PyObject *value, void *Py_UNUSED(ignored))
 {
     PyObject *result;
+    CDataObject *self = _CDataObject_CAST(myself);
 
     if (value == NULL) {
         PyErr_SetString(PyExc_TypeError,
@@ -5185,7 +5194,7 @@ Simple_set_value(CDataObject *self, PyObject *value, void *Py_UNUSED(ignored))
 
     ctypes_state *st = get_module_state_by_def(Py_TYPE(Py_TYPE(self)));
     StgInfo *info;
-    if (PyStgInfo_FromObject(st, (PyObject *)self, &info) < 0) {
+    if (PyStgInfo_FromObject(st, myself, &info) < 0) {
         return -1;
     }
     assert(info); /* Cannot be NULL for CDataObject instances */
@@ -5202,7 +5211,7 @@ Simple_set_value(CDataObject *self, PyObject *value, void *Py_UNUSED(ignored))
 }
 
 static int
-Simple_init(CDataObject *self, PyObject *args, PyObject *kw)
+Simple_init(PyObject *self, PyObject *args, PyObject *kw)
 {
     PyObject *value = NULL;
     if (!PyArg_UnpackTuple(args, "__init__", 0, 1, &value))
@@ -5213,11 +5222,12 @@ Simple_init(CDataObject *self, PyObject *args, PyObject *kw)
 }
 
 static PyObject *
-Simple_get_value(CDataObject *self, void *Py_UNUSED(ignored))
+Simple_get_value(PyObject *myself, void *Py_UNUSED(ignored))
 {
+    CDataObject *self = _CDataObject_CAST(myself);
     ctypes_state *st = get_module_state_by_def(Py_TYPE(Py_TYPE(self)));
     StgInfo *info;
-    if (PyStgInfo_FromObject(st, (PyObject *)self, &info) < 0) {
+    if (PyStgInfo_FromObject(st, myself, &info) < 0) {
         return NULL;
     }
     assert(info); /* Cannot be NULL for CDataObject instances */
@@ -5230,7 +5240,7 @@ Simple_get_value(CDataObject *self, void *Py_UNUSED(ignored))
 }
 
 static PyGetSetDef Simple_getsets[] = {
-    { "value", (getter)Simple_get_value, (setter)Simple_set_value,
+    { "value", Simple_get_value, Simple_set_value,
       "current value", NULL },
     { NULL, NULL }
 };
@@ -5252,7 +5262,7 @@ Simple_from_outparm_impl(PyObject *self, PyTypeObject *cls)
         return Py_NewRef(self);
     }
     /* call stginfo->getfunc */
-    return Simple_get_value((CDataObject *)self, NULL);
+    return Simple_get_value(self, NULL);
 }
 
 static PyMethodDef Simple_methods[] = {
@@ -5260,9 +5270,10 @@ static PyMethodDef Simple_methods[] = {
     { NULL, NULL },
 };
 
-static int Simple_bool(CDataObject *self)
+static int Simple_bool(PyObject *myself)
 {
     int cmp;
+    CDataObject *self = _CDataObject_CAST(myself);
     LOCK_PTR(self);
     cmp = memcmp(self->b_ptr, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", self->b_size);
     UNLOCK_PTR(self);
@@ -5271,7 +5282,7 @@ static int Simple_bool(CDataObject *self)
 
 /* "%s(%s)" % (self.__class__.__name__, self.value) */
 static PyObject *
-Simple_repr(CDataObject *self)
+Simple_repr(PyObject *self)
 {
     PyObject *val, *result;
     ctypes_state *st = get_module_state_by_def(Py_TYPE(Py_TYPE(self)));
@@ -5318,7 +5329,7 @@ static PyType_Spec pycsimple_spec = {
 static PyObject *
 Pointer_item(PyObject *myself, Py_ssize_t index)
 {
-    CDataObject *self = (CDataObject *)myself;
+    CDataObject *self = _CDataObject_CAST(myself);
     Py_ssize_t size;
     Py_ssize_t offset;
     PyObject *proto;
@@ -5332,7 +5343,7 @@ Pointer_item(PyObject *myself, Py_ssize_t index)
 
     ctypes_state *st = get_module_state_by_def(Py_TYPE(Py_TYPE(myself)));
     StgInfo *stginfo;
-    if (PyStgInfo_FromObject(st, (PyObject *)self, &stginfo) < 0) {
+    if (PyStgInfo_FromObject(st, myself, &stginfo) < 0) {
         return NULL;
     }
     assert(stginfo); /* Cannot be NULL for pointer object instances */
@@ -5350,14 +5361,14 @@ Pointer_item(PyObject *myself, Py_ssize_t index)
     size = iteminfo->size;
     offset = index * iteminfo->size;
 
-    return PyCData_get(st, proto, stginfo->getfunc, (PyObject *)self,
+    return PyCData_get(st, proto, stginfo->getfunc, myself,
                        index, size, (char *)((char *)deref + offset));
 }
 
 static int
 Pointer_ass_item(PyObject *myself, Py_ssize_t index, PyObject *value)
 {
-    CDataObject *self = (CDataObject *)myself;
+    CDataObject *self = _CDataObject_CAST(myself);
     Py_ssize_t size;
     Py_ssize_t offset;
     PyObject *proto;
@@ -5377,7 +5388,7 @@ Pointer_ass_item(PyObject *myself, Py_ssize_t index, PyObject *value)
 
     ctypes_state *st = get_module_state_by_def(Py_TYPE(Py_TYPE(myself)));
     StgInfo *stginfo;
-    if (PyStgInfo_FromObject(st, (PyObject *)self, &stginfo) < 0) {
+    if (PyStgInfo_FromObject(st, myself, &stginfo) < 0) {
         return -1;
     }
     assert(stginfo); /* Cannot be NULL for pointer instances */
@@ -5395,14 +5406,14 @@ Pointer_ass_item(PyObject *myself, Py_ssize_t index, PyObject *value)
     size = iteminfo->size;
     offset = index * iteminfo->size;
 
-    return PyCData_set(st, (PyObject *)self, proto, stginfo->setfunc, value,
+    return PyCData_set(st, myself, proto, stginfo->setfunc, value,
                        index, size, ((char *)deref + offset));
 }
 
 static PyObject *
-Pointer_get_contents(CDataObject *self, void *closure)
+Pointer_get_contents(PyObject *self, void *closure)
 {
-    void *deref = locked_deref(self);
+    void *deref = locked_deref(_CDataObject_CAST(self));
     if (deref == NULL) {
         PyErr_SetString(PyExc_ValueError,
                         "NULL pointer access");
@@ -5411,21 +5422,20 @@ Pointer_get_contents(CDataObject *self, void *closure)
 
     ctypes_state *st = get_module_state_by_def(Py_TYPE(Py_TYPE(self)));
     StgInfo *stginfo;
-    if (PyStgInfo_FromObject(st, (PyObject *)self, &stginfo) < 0) {
+    if (PyStgInfo_FromObject(st, self, &stginfo) < 0) {
         return NULL;
     }
     assert(stginfo); /* Cannot be NULL for pointer instances */
 
-    return PyCData_FromBaseObj(st, stginfo->proto,
-                             (PyObject *)self, 0,
-                             deref);
+    return PyCData_FromBaseObj(st, stginfo->proto, self, 0, deref);
 }
 
 static int
-Pointer_set_contents(CDataObject *self, PyObject *value, void *closure)
+Pointer_set_contents(PyObject *myself, PyObject *value, void *closure)
 {
     CDataObject *dst;
     PyObject *keep;
+    CDataObject *self = _CDataObject_CAST(myself);
 
     if (value == NULL) {
         PyErr_SetString(PyExc_TypeError,
@@ -5434,7 +5444,7 @@ Pointer_set_contents(CDataObject *self, PyObject *value, void *closure)
     }
     ctypes_state *st = get_module_state_by_def(Py_TYPE(Py_TYPE(self)));
     StgInfo *stginfo;
-    if (PyStgInfo_FromObject(st, (PyObject *)self, &stginfo) < 0) {
+    if (PyStgInfo_FromObject(st, myself, &stginfo) < 0) {
         return -1;
     }
     assert(stginfo); /* Cannot be NULL for pointer instances */
@@ -5473,17 +5483,15 @@ Pointer_set_contents(CDataObject *self, PyObject *value, void *closure)
 }
 
 static PyGetSetDef Pointer_getsets[] = {
-    { "contents", (getter)Pointer_get_contents,
-      (setter)Pointer_set_contents,
+    { "contents", Pointer_get_contents, Pointer_set_contents,
       "the object this pointer points to (read-write)", NULL },
     { NULL, NULL }
 };
 
 static int
-Pointer_init(CDataObject *self, PyObject *args, PyObject *kw)
+Pointer_init(PyObject *self, PyObject *args, PyObject *kw)
 {
     PyObject *value = NULL;
-
     if (!PyArg_UnpackTuple(args, "POINTER", 0, 1, &value))
         return -1;
     if (value == NULL)
@@ -5510,7 +5518,6 @@ Pointer_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 static PyObject *
 Pointer_subscript(PyObject *myself, PyObject *item)
 {
-    CDataObject *self = (CDataObject *)myself;
     if (PyIndex_Check(item)) {
         Py_ssize_t i = PyNumber_AsSsize_t(item, PyExc_IndexError);
         if (i == -1 && PyErr_Occurred())
@@ -5576,7 +5583,7 @@ Pointer_subscript(PyObject *myself, PyObject *item)
 
         ctypes_state *st = get_module_state_by_def(Py_TYPE(Py_TYPE(myself)));
         StgInfo *stginfo;
-        if (PyStgInfo_FromObject(st, (PyObject *)self, &stginfo) < 0) {
+        if (PyStgInfo_FromObject(st, myself, &stginfo) < 0) {
             return NULL;
         }
         assert(stginfo); /* Cannot be NULL for pointer instances */
@@ -5588,7 +5595,7 @@ Pointer_subscript(PyObject *myself, PyObject *item)
         }
         assert(iteminfo);
         if (iteminfo->getfunc == _ctypes_get_fielddesc("c")->getfunc) {
-            char *ptr = locked_deref(self);
+            char *ptr = locked_deref(_CDataObject_CAST(myself));
             char *dest;
 
             if (len <= 0)
@@ -5614,7 +5621,7 @@ Pointer_subscript(PyObject *myself, PyObject *item)
             return np;
         }
         if (iteminfo->getfunc == _ctypes_get_fielddesc("u")->getfunc) {
-            wchar_t *ptr = locked_deref(self);
+            wchar_t *ptr = locked_deref(_CDataObject_CAST(myself));
             wchar_t *dest;
 
             if (len <= 0)
@@ -5658,8 +5665,9 @@ Pointer_subscript(PyObject *myself, PyObject *item)
 }
 
 static int
-Pointer_bool(CDataObject *self)
+Pointer_bool(PyObject *myself)
 {
+    CDataObject *self = _CDataObject_CAST(myself);
     return locked_deref(self) != NULL;
 }
 

From 0014d3dda479d142070ab94ba39ba10f0e0f958e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Mon, 20 Jan 2025 15:19:46 +0100
Subject: [PATCH 04/13] fix UBSan failures for `PyCFuncPtrObject`

---
 Modules/_ctypes/_ctypes.c | 29 ++++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
index 4d04710a099c9d..da382bfa83b2a9 100644
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -3490,6 +3490,8 @@ generic_pycdata_new(ctypes_state *st,
   PyCFuncPtr_Type
 */
 
+#define _PyCFuncPtrObject_CAST(op)  ((PyCFuncPtrObject *)(op))
+
 /*[clinic input]
 @critical_section
 @setter
@@ -4418,7 +4420,7 @@ _build_result(PyObject *result, PyObject *callargs,
 }
 
 static PyObject *
-PyCFuncPtr_call(PyCFuncPtrObject *self, PyObject *inargs, PyObject *kwds)
+PyCFuncPtr_call(PyObject *myself, PyObject *inargs, PyObject *kwds)
 {
     PyObject *restype;
     PyObject *converters;
@@ -4431,6 +4433,7 @@ PyCFuncPtr_call(PyCFuncPtrObject *self, PyObject *inargs, PyObject *kwds)
     IUnknown *piunk = NULL;
 #endif
     void *pProc = NULL;
+    PyCFuncPtrObject *self = _PyCFuncPtrObject_CAST(myself);
 
     int inoutmask;
     int outmask;
@@ -4438,7 +4441,7 @@ PyCFuncPtr_call(PyCFuncPtrObject *self, PyObject *inargs, PyObject *kwds)
 
     ctypes_state *st = get_module_state_by_def(Py_TYPE(Py_TYPE(self)));
     StgInfo *info;
-    if (PyStgInfo_FromObject(st, (PyObject *)self, &info) < 0) {
+    if (PyStgInfo_FromObject(st, myself, &info) < 0) {
         return NULL;
     }
     assert(info); /* Cannot be NULL for PyCFuncPtrObject instances */
@@ -4556,8 +4559,9 @@ PyCFuncPtr_call(PyCFuncPtrObject *self, PyObject *inargs, PyObject *kwds)
 }
 
 static int
-PyCFuncPtr_traverse(PyCFuncPtrObject *self, visitproc visit, void *arg)
+PyCFuncPtr_traverse(PyObject *op, visitproc visit, void *arg)
 {
+    PyCFuncPtrObject *self = _PyCFuncPtrObject_CAST(op);
     Py_VISIT(self->callable);
     Py_VISIT(self->restype);
     Py_VISIT(self->checker);
@@ -4566,12 +4570,13 @@ PyCFuncPtr_traverse(PyCFuncPtrObject *self, visitproc visit, void *arg)
     Py_VISIT(self->converters);
     Py_VISIT(self->paramflags);
     Py_VISIT(self->thunk);
-    return PyCData_traverse((CDataObject *)self, visit, arg);
+    return PyCData_traverse(op, visit, arg);
 }
 
 static int
-PyCFuncPtr_clear(PyCFuncPtrObject *self)
+PyCFuncPtr_clear(PyObject *op)
 {
+    PyCFuncPtrObject *self = _PyCFuncPtrObject_CAST(op);
     Py_CLEAR(self->callable);
     Py_CLEAR(self->restype);
     Py_CLEAR(self->checker);
@@ -4580,22 +4585,23 @@ PyCFuncPtr_clear(PyCFuncPtrObject *self)
     Py_CLEAR(self->converters);
     Py_CLEAR(self->paramflags);
     Py_CLEAR(self->thunk);
-    return PyCData_clear((CDataObject *)self);
+    return PyCData_clear(self);
 }
 
 static void
-PyCFuncPtr_dealloc(PyCFuncPtrObject *self)
+PyCFuncPtr_dealloc(PyObject *self)
 {
     PyObject_GC_UnTrack(self);
-    PyCFuncPtr_clear(self);
+    (void)PyCFuncPtr_clear(self);
     PyTypeObject *type = Py_TYPE(self);
-    type->tp_free((PyObject *)self);
+    type->tp_free(self);
     Py_DECREF(type);
 }
 
 static PyObject *
-PyCFuncPtr_repr(PyCFuncPtrObject *self)
+PyCFuncPtr_repr(PyObject *op)
 {
+    PyCFuncPtrObject *self = _PyCFuncPtrObject_CAST(op);
 #ifdef MS_WIN32
     if (self->index)
         return PyUnicode_FromFormat("<COM method offset %d: %s at %p>",
@@ -4609,8 +4615,9 @@ PyCFuncPtr_repr(PyCFuncPtrObject *self)
 }
 
 static int
-PyCFuncPtr_bool(PyCFuncPtrObject *self)
+PyCFuncPtr_bool(PyObject *op)
 {
+    PyCFuncPtrObject *self = _PyCFuncPtrObject_CAST(op);
     return ((*(void **)self->b_ptr != NULL)
 #ifdef MS_WIN32
         || (self->index != 0)

From 5830275f3048d736a99080ff7f374354b2bc009f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Mon, 20 Jan 2025 15:23:46 +0100
Subject: [PATCH 05/13] fix UBSan failures for `PyCArgObject`

---
 Modules/_ctypes/callproc.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/Modules/_ctypes/callproc.c b/Modules/_ctypes/callproc.c
index 92eedff5ec94f1..404af3495837e2 100644
--- a/Modules/_ctypes/callproc.c
+++ b/Modules/_ctypes/callproc.c
@@ -477,6 +477,8 @@ check_hresult(PyObject *self, PyObject *args)
 
 /**************************************************************/
 
+#define _PyCArgObject_CAST(op)  ((PyCArgObject *)(op))
+
 PyCArgObject *
 PyCArgObject_new(ctypes_state *st)
 {
@@ -493,27 +495,29 @@ PyCArgObject_new(ctypes_state *st)
 }
 
 static int
-PyCArg_traverse(PyCArgObject *self, visitproc visit, void *arg)
+PyCArg_traverse(PyObject *op, visitproc visit, void *arg)
 {
+    PyCArgObject *self = _PyCArgObject_CAST(op);
     Py_VISIT(Py_TYPE(self));
     Py_VISIT(self->obj);
     return 0;
 }
 
 static int
-PyCArg_clear(PyCArgObject *self)
+PyCArg_clear(PyObject *op)
 {
+    PyCArgObject *self = _PyCArgObject_CAST(op);
     Py_CLEAR(self->obj);
     return 0;
 }
 
 static void
-PyCArg_dealloc(PyCArgObject *self)
+PyCArg_dealloc(PyObject *self)
 {
     PyTypeObject *tp = Py_TYPE(self);
     PyObject_GC_UnTrack(self);
     (void)PyCArg_clear(self);
-    tp->tp_free((PyObject *)self);
+    tp->tp_free(self);
     Py_DECREF(tp);
 }
 
@@ -524,8 +528,9 @@ is_literal_char(unsigned char c)
 }
 
 static PyObject *
-PyCArg_repr(PyCArgObject *self)
+PyCArg_repr(PyObject *self)
 {
+    PyCArgObject *self = _PyCArgObject_CAST(op);
     switch(self->tag) {
     case 'b':
     case 'B':

From e193e6f9e250bc6b6eb9aae61f5ce427ec4aa9cb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Mon, 20 Jan 2025 15:28:13 +0100
Subject: [PATCH 06/13] fix UBSan failures for `CFieldObject`

---
 Modules/_ctypes/cfield.c | 35 +++++++++++++++++++++--------------
 1 file changed, 21 insertions(+), 14 deletions(-)

diff --git a/Modules/_ctypes/cfield.c b/Modules/_ctypes/cfield.c
index dcac9da75360a4..8e717fc0bef0de 100644
--- a/Modules/_ctypes/cfield.c
+++ b/Modules/_ctypes/cfield.c
@@ -41,6 +41,9 @@ static void pymem_destructor(PyObject *ptr)
 /*
   PyCField_Type
 */
+
+#define _CFieldObject_CAST(op)  ((CFieldObject *)(op))
+
 /*[clinic input]
 class _ctypes.CField "PyObject *" "PyObject"
 [clinic start generated code]*/
@@ -194,17 +197,18 @@ PyCField_new_impl(PyTypeObject *type, PyObject *name, PyObject *proto,
 
 
 static int
-PyCField_set(CFieldObject *self, PyObject *inst, PyObject *value)
+PyCField_set(PyObject *op, PyObject *inst, PyObject *value)
 {
     CDataObject *dst;
     char *ptr;
+    CFieldObject *self = _CFieldObject_CAST(op);
     ctypes_state *st = get_module_state_by_class(Py_TYPE(self));
     if (!CDataObject_Check(st, inst)) {
         PyErr_SetString(PyExc_TypeError,
                         "not a ctype instance");
         return -1;
     }
-    dst = (CDataObject *)inst;
+    dst = _CFieldObject_CAST(inst);
     ptr = dst->b_ptr + self->offset;
     if (value == NULL) {
         PyErr_SetString(PyExc_TypeError,
@@ -212,13 +216,14 @@ PyCField_set(CFieldObject *self, PyObject *inst, PyObject *value)
         return -1;
     }
     return PyCData_set(st, inst, self->proto, self->setfunc, value,
-                     self->index, self->size, ptr);
+                       self->index, self->size, ptr);
 }
 
 static PyObject *
-PyCField_get(CFieldObject *self, PyObject *inst, PyTypeObject *type)
+PyCField_get(PyObject *op, PyObject *inst, PyTypeObject *type)
 {
     CDataObject *src;
+    CFieldObject *self = _CFieldObject_CAST(op);
     if (inst == NULL) {
         return Py_NewRef(self);
     }
@@ -228,21 +233,21 @@ PyCField_get(CFieldObject *self, PyObject *inst, PyTypeObject *type)
                         "not a ctype instance");
         return NULL;
     }
-    src = (CDataObject *)inst;
+    src = _CFieldObject_CAST(inst);
     return PyCData_get(st, self->proto, self->getfunc, inst,
-                     self->index, self->size, src->b_ptr + self->offset);
+                       self->index, self->size, src->b_ptr + self->offset);
 }
 
 static PyObject *
 PyCField_get_offset(PyObject *self, void *data)
 {
-    return PyLong_FromSsize_t(((CFieldObject *)self)->offset);
+    return PyLong_FromSsize_t(_CFieldObject_CAST(self)->offset);
 }
 
 static PyObject *
 PyCField_get_size(PyObject *self, void *data)
 {
-    return PyLong_FromSsize_t(((CFieldObject *)self)->size);
+    return PyLong_FromSsize_t(_CFieldObject_CAST(self)->size);
 }
 
 static PyGetSetDef PyCField_getset[] = {
@@ -252,17 +257,20 @@ static PyGetSetDef PyCField_getset[] = {
 };
 
 static int
-PyCField_traverse(CFieldObject *self, visitproc visit, void *arg)
+PyCField_traverse(PyObject *op, visitproc visit, void *arg)
 {
+    CFieldObject *self = _CFieldObject_CAST(op);
     Py_VISIT(Py_TYPE(self));
     Py_VISIT(self->proto);
     return 0;
 }
 
 static int
-PyCField_clear(CFieldObject *self)
+PyCField_clear(PyObject *op)
 {
+    CFieldObject *self = _CFieldObject_CAST(op);
     Py_CLEAR(self->proto);
+    Py_CLEAR(self->name);
     return 0;
 }
 
@@ -271,17 +279,16 @@ PyCField_dealloc(PyObject *self)
 {
     PyTypeObject *tp = Py_TYPE(self);
     PyObject_GC_UnTrack(self);
-    CFieldObject *self_cf = (CFieldObject *)self;
-    (void)PyCField_clear(self_cf);
-    Py_CLEAR(self_cf->name);
+    (void)PyCField_clear(self);
     Py_TYPE(self)->tp_free(self);
     Py_DECREF(tp);
 }
 
 static PyObject *
-PyCField_repr(CFieldObject *self)
+PyCField_repr(PyObject *op)
 {
     PyObject *result;
+    CFieldObject *self = _CFieldObject_CAST(op);
     Py_ssize_t bits = NUM_BITS(self->size);
     Py_ssize_t size = LOW_BIT(self->size);
     const char *name;

From df5d4778dd87116951e268341b8dbd7acccad89e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Mon, 20 Jan 2025 15:30:46 +0100
Subject: [PATCH 07/13] remove redundant docstring casts

---
 Modules/_ctypes/_ctypes.c   | 2 +-
 Modules/_ctypes/callbacks.c | 2 +-
 Modules/_ctypes/cfield.c    | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
index da382bfa83b2a9..a1459ccc61e96e 100644
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -5770,7 +5770,7 @@ comerror_dealloc(PyObject *self)
 }
 
 static PyType_Slot comerror_slots[] = {
-    {Py_tp_doc, (void *)PyDoc_STR(comerror_doc)},
+    {Py_tp_doc, PyDoc_STR(comerror_doc)},
     {Py_tp_init, comerror_init},
     {Py_tp_traverse, comerror_traverse},
     {Py_tp_dealloc, comerror_dealloc},
diff --git a/Modules/_ctypes/callbacks.c b/Modules/_ctypes/callbacks.c
index 89c0749a093765..07ccdefaefe2c5 100644
--- a/Modules/_ctypes/callbacks.c
+++ b/Modules/_ctypes/callbacks.c
@@ -63,7 +63,7 @@ CThunkObject_dealloc(PyObject *myself)
 }
 
 static PyType_Slot cthunk_slots[] = {
-    {Py_tp_doc, (void *)PyDoc_STR("CThunkObject")},
+    {Py_tp_doc, PyDoc_STR("CThunkObject")},
     {Py_tp_dealloc, CThunkObject_dealloc},
     {Py_tp_traverse, CThunkObject_traverse},
     {Py_tp_clear, CThunkObject_clear},
diff --git a/Modules/_ctypes/cfield.c b/Modules/_ctypes/cfield.c
index 8e717fc0bef0de..0ed87ebdb26230 100644
--- a/Modules/_ctypes/cfield.c
+++ b/Modules/_ctypes/cfield.c
@@ -310,7 +310,7 @@ static PyType_Slot cfield_slots[] = {
     {Py_tp_new, PyCField_new},
     {Py_tp_dealloc, PyCField_dealloc},
     {Py_tp_repr, PyCField_repr},
-    {Py_tp_doc, (void *)PyDoc_STR("Structure/Union member")},
+    {Py_tp_doc, PyDoc_STR("Structure/Union member")},
     {Py_tp_traverse, PyCField_traverse},
     {Py_tp_clear, PyCField_clear},
     {Py_tp_getset, PyCField_getset},

From 753ba2afdc3b1d4c57e9941d94a003af267c89be Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Mon, 20 Jan 2025 15:15:38 +0100
Subject: [PATCH 08/13] remove redundant PyObject casts

---
 Modules/_ctypes/_ctypes.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
index a1459ccc61e96e..b6083be0772498 100644
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -682,7 +682,7 @@ StructUnionType_init(PyObject *self, PyObject *args, PyObject *kwds, int isStruc
 
     info->paramfunc = StructUnionType_paramfunc;
 
-    if (PyDict_GetItemRef((PyObject *)attrdict, &_Py_ID(_fields_), &fields) < 0) {
+    if (PyDict_GetItemRef(attrdict, &_Py_ID(_fields_), &fields) < 0) {
         Py_DECREF(attrdict);
         return -1;
     }
@@ -2649,7 +2649,7 @@ make_funcptrtype_dict(ctypes_state *st, PyObject *attrdict, StgInfo *stginfo)
     stginfo->getfunc = NULL;
     stginfo->ffi_type_pointer = ffi_type_pointer;
 
-    if (PyDict_GetItemRef((PyObject *)attrdict, &_Py_ID(_flags_), &ob) < 0) {
+    if (PyDict_GetItemRef(attrdict, &_Py_ID(_flags_), &ob) < 0) {
         return -1;
     }
     if (!ob || !PyLong_Check(ob)) {
@@ -2662,7 +2662,7 @@ make_funcptrtype_dict(ctypes_state *st, PyObject *attrdict, StgInfo *stginfo)
     Py_DECREF(ob);
 
     /* _argtypes_ is optional... */
-    if (PyDict_GetItemRef((PyObject *)attrdict, &_Py_ID(_argtypes_), &ob) < 0) {
+    if (PyDict_GetItemRef(attrdict, &_Py_ID(_argtypes_), &ob) < 0) {
         return -1;
     }
     if (ob) {
@@ -2675,7 +2675,7 @@ make_funcptrtype_dict(ctypes_state *st, PyObject *attrdict, StgInfo *stginfo)
         stginfo->converters = converters;
     }
 
-    if (PyDict_GetItemRef((PyObject *)attrdict, &_Py_ID(_restype_), &ob) < 0) {
+    if (PyDict_GetItemRef(attrdict, &_Py_ID(_restype_), &ob) < 0) {
         return -1;
     }
     if (ob) {
@@ -2697,7 +2697,7 @@ make_funcptrtype_dict(ctypes_state *st, PyObject *attrdict, StgInfo *stginfo)
         }
     }
 /* XXX later, maybe.
-    if (PyDict_GetItemRef((PyObject *)attrdict, &_Py _ID(_errcheck_), &ob) < 0) {
+    if (PyDict_GetItemRef(attrdict, &_Py _ID(_errcheck_), &ob) < 0) {
         return -1;
     }
     if (ob) {

From 441a0be62ce03335342817332034f99683e17a22 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Mon, 20 Jan 2025 15:39:26 +0100
Subject: [PATCH 09/13] fix compilation errors

---
 Modules/_ctypes/_ctypes.c  | 38 +++++++++++++++-----------------------
 Modules/_ctypes/callproc.c |  4 +---
 Modules/_ctypes/cfield.c   |  6 ++----
 Modules/_ctypes/ctypes.h   | 15 +++++++++++++--
 4 files changed, 31 insertions(+), 32 deletions(-)

diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
index b6083be0772498..89def398613b60 100644
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -168,13 +168,12 @@ _DictRemover_clear(PyObject *myself)
 }
 
 static void
-_DictRemover_dealloc(PyObject *myself)
+_DictRemover_dealloc(PyObject *self)
 {
-    PyTypeObject *tp = Py_TYPE(myself);
-    DictRemoverObject *self = _DictRemoverObject_CAST(myself);
-    PyObject_GC_UnTrack(myself);
+    PyTypeObject *tp = Py_TYPE(self);
+    PyObject_GC_UnTrack(self);
     (void)_DictRemover_clear(self);
-    tp->tp_free(myself);
+    tp->tp_free(self);
     Py_DECREF(tp);
 }
 
@@ -416,22 +415,21 @@ StructParam_traverse(PyObject *self, visitproc visit, void *arg)
 }
 
 static int
-StructParam_clear(PyObject *op)
+StructParam_clear(PyObject *myself)
 {
-    StructParamObject *self = _StructParamObject_CAST(op);
+    StructParamObject *self = _StructParamObject_CAST(myself);
     Py_CLEAR(self->keep);
     return 0;
 }
 
 static void
-StructParam_dealloc(PyObject *myself)
+StructParam_dealloc(PyObject *self)
 {
-    StructParamObject *self = _StructParamObject_CAST(myself);
     PyTypeObject *tp = Py_TYPE(self);
-    PyObject_GC_UnTrack(myself);
+    PyObject_GC_UnTrack(self);
     (void)StructParam_clear(self);
-    PyMem_Free(self->ptr);
-    tp->tp_free(myself);
+    PyMem_Free(_StructParamObject_CAST(self)->ptr);
+    tp->tp_free(self);
     Py_DECREF(tp);
 }
 
@@ -1417,8 +1415,6 @@ static PyType_Spec pycpointer_type_spec = {
   attribute, and a _type_ attribute.
 */
 
-#define _CDataObject_CAST(op)   ((CDataObject *)(op))
-
 static int
 CharArray_set_raw(PyObject *op, PyObject *value, void *Py_UNUSED(ignored))
 {
@@ -3262,10 +3258,7 @@ PyObject *
 PyCData_get(ctypes_state *st, PyObject *type, GETFUNC getfunc, PyObject *src,
           Py_ssize_t index, Py_ssize_t size, char *adr)
 {
-#ifdef Py_GIL_DISABLED
-    // This isn't used if the GIL is enabled, so it causes a compiler warning.
-    CDataObject *cdata = (CDataObject *)src;
-#endif
+    CDataObject *cdata = _CDataObject_CAST(src);
     if (getfunc) {
         PyObject *res;
         LOCK_PTR(cdata);
@@ -3490,8 +3483,6 @@ generic_pycdata_new(ctypes_state *st,
   PyCFuncPtr_Type
 */
 
-#define _PyCFuncPtrObject_CAST(op)  ((PyCFuncPtrObject *)(op))
-
 /*[clinic input]
 @critical_section
 @setter
@@ -4585,7 +4576,7 @@ PyCFuncPtr_clear(PyObject *op)
     Py_CLEAR(self->converters);
     Py_CLEAR(self->paramflags);
     Py_CLEAR(self->thunk);
-    return PyCData_clear(self);
+    return PyCData_clear(op);
 }
 
 static void
@@ -5525,6 +5516,7 @@ Pointer_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 static PyObject *
 Pointer_subscript(PyObject *myself, PyObject *item)
 {
+    CDataObject *self = _CDataObject_CAST(myself);
     if (PyIndex_Check(item)) {
         Py_ssize_t i = PyNumber_AsSsize_t(item, PyExc_IndexError);
         if (i == -1 && PyErr_Occurred())
@@ -5602,7 +5594,7 @@ Pointer_subscript(PyObject *myself, PyObject *item)
         }
         assert(iteminfo);
         if (iteminfo->getfunc == _ctypes_get_fielddesc("c")->getfunc) {
-            char *ptr = locked_deref(_CDataObject_CAST(myself));
+            char *ptr = locked_deref(self);
             char *dest;
 
             if (len <= 0)
@@ -5628,7 +5620,7 @@ Pointer_subscript(PyObject *myself, PyObject *item)
             return np;
         }
         if (iteminfo->getfunc == _ctypes_get_fielddesc("u")->getfunc) {
-            wchar_t *ptr = locked_deref(_CDataObject_CAST(myself));
+            wchar_t *ptr = locked_deref(self);
             wchar_t *dest;
 
             if (len <= 0)
diff --git a/Modules/_ctypes/callproc.c b/Modules/_ctypes/callproc.c
index 404af3495837e2..c6b6460126ca90 100644
--- a/Modules/_ctypes/callproc.c
+++ b/Modules/_ctypes/callproc.c
@@ -477,8 +477,6 @@ check_hresult(PyObject *self, PyObject *args)
 
 /**************************************************************/
 
-#define _PyCArgObject_CAST(op)  ((PyCArgObject *)(op))
-
 PyCArgObject *
 PyCArgObject_new(ctypes_state *st)
 {
@@ -528,7 +526,7 @@ is_literal_char(unsigned char c)
 }
 
 static PyObject *
-PyCArg_repr(PyObject *self)
+PyCArg_repr(PyObject *op)
 {
     PyCArgObject *self = _PyCArgObject_CAST(op);
     switch(self->tag) {
diff --git a/Modules/_ctypes/cfield.c b/Modules/_ctypes/cfield.c
index 0ed87ebdb26230..81a660b51b0ffc 100644
--- a/Modules/_ctypes/cfield.c
+++ b/Modules/_ctypes/cfield.c
@@ -42,8 +42,6 @@ static void pymem_destructor(PyObject *ptr)
   PyCField_Type
 */
 
-#define _CFieldObject_CAST(op)  ((CFieldObject *)(op))
-
 /*[clinic input]
 class _ctypes.CField "PyObject *" "PyObject"
 [clinic start generated code]*/
@@ -208,7 +206,7 @@ PyCField_set(PyObject *op, PyObject *inst, PyObject *value)
                         "not a ctype instance");
         return -1;
     }
-    dst = _CFieldObject_CAST(inst);
+    dst = _CDataObject_CAST(inst);
     ptr = dst->b_ptr + self->offset;
     if (value == NULL) {
         PyErr_SetString(PyExc_TypeError,
@@ -233,7 +231,7 @@ PyCField_get(PyObject *op, PyObject *inst, PyTypeObject *type)
                         "not a ctype instance");
         return NULL;
     }
-    src = _CFieldObject_CAST(inst);
+    src = _CDataObject_CAST(inst);
     return PyCData_get(st, self->proto, self->getfunc, inst,
                        self->index, self->size, src->b_ptr + self->offset);
 }
diff --git a/Modules/_ctypes/ctypes.h b/Modules/_ctypes/ctypes.h
index cc09639e21f7c2..55d071a33d74d9 100644
--- a/Modules/_ctypes/ctypes.h
+++ b/Modules/_ctypes/ctypes.h
@@ -112,7 +112,10 @@ extern PyType_Spec cfield_spec;
 extern PyType_Spec cthunk_spec;
 
 typedef struct tagPyCArgObject PyCArgObject;
+#define _PyCArgObject_CAST(op)  ((PyCArgObject *)(op))
+
 typedef struct tagCDataObject CDataObject;
+#define _CDataObject_CAST(op)   ((CDataObject *)(op))
 
 // GETFUNC: convert the C value at *ptr* to Python object, return the object
 // SETFUNC: write content of the PyObject *value* to the location at *ptr*;
@@ -176,6 +179,7 @@ typedef struct {
     ffi_type *ffi_restype;
     ffi_type *atypes[1];
 } CThunkObject;
+#define _CThunkObject_CAST(op)          ((CThunkObject *)(op))
 #define CThunk_CheckExact(st, v)        Py_IS_TYPE(v, st->PyCThunk_Type)
 
 typedef struct {
@@ -208,6 +212,7 @@ typedef struct {
 #endif
     PyObject *paramflags;
 } PyCFuncPtrObject;
+#define _PyCFuncPtrObject_CAST(op)  ((PyCFuncPtrObject *)(op))
 
 extern int PyCStructUnionType_update_stginfo(PyObject *fields, PyObject *type, int isStruct);
 extern int PyType_stginfo(PyTypeObject *self, Py_ssize_t *psize, Py_ssize_t *palign, Py_ssize_t *plength);
@@ -268,6 +273,7 @@ typedef struct CFieldObject {
 
     PyObject *name;                     /* exact PyUnicode */
 } CFieldObject;
+#define _CFieldObject_CAST(op)  ((CFieldObject *)(op))
 
 /****************************************************************
  StgInfo
@@ -404,6 +410,7 @@ struct tagPyCArgObject {
     PyObject *obj;
     Py_ssize_t size; /* for the 'V' tag */
 };
+#define _PyCArgObject_CAST(op)  ((PyCArgObject *)(op))
 
 #define PyCArg_CheckExact(st, v)        Py_IS_TYPE(v, st->PyCArg_Type)
 extern PyCArgObject *PyCArgObject_new(ctypes_state *st);
@@ -550,8 +557,12 @@ PyStgInfo_Init(ctypes_state *state, PyTypeObject *type)
 #  define LOCK_PTR(self) Py_BEGIN_CRITICAL_SECTION(self)
 #  define UNLOCK_PTR(self) Py_END_CRITICAL_SECTION()
 #else
-#  define LOCK_PTR(self)
-#  define UNLOCK_PTR(self)
+/*
+ * Dummy functions instead of macros so that 'self' can be
+ * unused in the caller without triggering a compiler warning.
+ */
+static inline void LOCK_PTR(CDataObject *Py_UNUSED(self)) {}
+static inline void UNLOCK_PTR(CDataObject *Py_UNUSED(self)) {}
 #endif
 
 static inline void

From 53582516925d2151f07ddc21b1f4ca69c75955af Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Mon, 20 Jan 2025 16:37:56 +0100
Subject: [PATCH 10/13] consistency & warnings patches

---
 Modules/_ctypes/_ctypes.c   | 60 ++++++++++++++++++-------------------
 Modules/_ctypes/callbacks.c |  2 +-
 Modules/_ctypes/cfield.c    |  3 +-
 3 files changed, 32 insertions(+), 33 deletions(-)

diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
index 89def398613b60..5c18d41c169b58 100644
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -168,12 +168,12 @@ _DictRemover_clear(PyObject *myself)
 }
 
 static void
-_DictRemover_dealloc(PyObject *self)
+_DictRemover_dealloc(PyObject *myself)
 {
-    PyTypeObject *tp = Py_TYPE(self);
-    PyObject_GC_UnTrack(self);
-    (void)_DictRemover_clear(self);
-    tp->tp_free(self);
+    PyTypeObject *tp = Py_TYPE(myself);
+    PyObject_GC_UnTrack(myself);
+    (void)_DictRemover_clear(myself);
+    tp->tp_free(myself);
     Py_DECREF(tp);
 }
 
@@ -423,13 +423,13 @@ StructParam_clear(PyObject *myself)
 }
 
 static void
-StructParam_dealloc(PyObject *self)
+StructParam_dealloc(PyObject *myself)
 {
-    PyTypeObject *tp = Py_TYPE(self);
-    PyObject_GC_UnTrack(self);
-    (void)StructParam_clear(self);
-    PyMem_Free(_StructParamObject_CAST(self)->ptr);
-    tp->tp_free(self);
+    PyTypeObject *tp = Py_TYPE(myself);
+    PyObject_GC_UnTrack(myself);
+    (void)StructParam_clear(myself);
+    PyMem_Free(_StructParamObject_CAST(myself)->ptr);
+    tp->tp_free(myself);
     Py_DECREF(tp);
 }
 
@@ -4411,7 +4411,7 @@ _build_result(PyObject *result, PyObject *callargs,
 }
 
 static PyObject *
-PyCFuncPtr_call(PyObject *myself, PyObject *inargs, PyObject *kwds)
+PyCFuncPtr_call(PyObject *op, PyObject *inargs, PyObject *kwds)
 {
     PyObject *restype;
     PyObject *converters;
@@ -4424,7 +4424,7 @@ PyCFuncPtr_call(PyObject *myself, PyObject *inargs, PyObject *kwds)
     IUnknown *piunk = NULL;
 #endif
     void *pProc = NULL;
-    PyCFuncPtrObject *self = _PyCFuncPtrObject_CAST(myself);
+    PyCFuncPtrObject *self = _PyCFuncPtrObject_CAST(op);
 
     int inoutmask;
     int outmask;
@@ -4432,7 +4432,7 @@ PyCFuncPtr_call(PyObject *myself, PyObject *inargs, PyObject *kwds)
 
     ctypes_state *st = get_module_state_by_def(Py_TYPE(Py_TYPE(self)));
     StgInfo *info;
-    if (PyStgInfo_FromObject(st, myself, &info) < 0) {
+    if (PyStgInfo_FromObject(st, op, &info) < 0) {
         return NULL;
     }
     assert(info); /* Cannot be NULL for PyCFuncPtrObject instances */
@@ -4819,8 +4819,8 @@ Array_init(PyObject *self, PyObject *args, PyObject *kw)
 static PyObject *
 Array_item(PyObject *myself, Py_ssize_t index)
 {
-    Py_ssize_t offset, size;
     CDataObject *self = _CDataObject_CAST(myself);
+    Py_ssize_t offset, size;
 
     if (index < 0 || index >= self->b_length) {
         PyErr_SetString(PyExc_IndexError,
@@ -5179,10 +5179,10 @@ class _ctypes.Simple "PyObject *" "clinic_state()->Simple_Type"
 /*[clinic end generated code: output=da39a3ee5e6b4b0d input=016c476c7aa8b8a8]*/
 
 static int
-Simple_set_value(PyObject *myself, PyObject *value, void *Py_UNUSED(ignored))
+Simple_set_value(PyObject *op, PyObject *value, void *Py_UNUSED(ignored))
 {
     PyObject *result;
-    CDataObject *self = _CDataObject_CAST(myself);
+    CDataObject *self = _CDataObject_CAST(op);
 
     if (value == NULL) {
         PyErr_SetString(PyExc_TypeError,
@@ -5192,7 +5192,7 @@ Simple_set_value(PyObject *myself, PyObject *value, void *Py_UNUSED(ignored))
 
     ctypes_state *st = get_module_state_by_def(Py_TYPE(Py_TYPE(self)));
     StgInfo *info;
-    if (PyStgInfo_FromObject(st, myself, &info) < 0) {
+    if (PyStgInfo_FromObject(st, op, &info) < 0) {
         return -1;
     }
     assert(info); /* Cannot be NULL for CDataObject instances */
@@ -5220,12 +5220,12 @@ Simple_init(PyObject *self, PyObject *args, PyObject *kw)
 }
 
 static PyObject *
-Simple_get_value(PyObject *myself, void *Py_UNUSED(ignored))
+Simple_get_value(PyObject *op, void *Py_UNUSED(ignored))
 {
-    CDataObject *self = _CDataObject_CAST(myself);
+    CDataObject *self = _CDataObject_CAST(op);
     ctypes_state *st = get_module_state_by_def(Py_TYPE(Py_TYPE(self)));
     StgInfo *info;
-    if (PyStgInfo_FromObject(st, myself, &info) < 0) {
+    if (PyStgInfo_FromObject(st, op, &info) < 0) {
         return NULL;
     }
     assert(info); /* Cannot be NULL for CDataObject instances */
@@ -5268,10 +5268,11 @@ static PyMethodDef Simple_methods[] = {
     { NULL, NULL },
 };
 
-static int Simple_bool(PyObject *myself)
+static int
+Simple_bool(PyObject *op)
 {
     int cmp;
-    CDataObject *self = _CDataObject_CAST(myself);
+    CDataObject *self = _CDataObject_CAST(op);
     LOCK_PTR(self);
     cmp = memcmp(self->b_ptr, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", self->b_size);
     UNLOCK_PTR(self);
@@ -5429,11 +5430,11 @@ Pointer_get_contents(PyObject *self, void *closure)
 }
 
 static int
-Pointer_set_contents(PyObject *myself, PyObject *value, void *closure)
+Pointer_set_contents(PyObject *op, PyObject *value, void *closure)
 {
     CDataObject *dst;
     PyObject *keep;
-    CDataObject *self = _CDataObject_CAST(myself);
+    CDataObject *self = _CDataObject_CAST(op);
 
     if (value == NULL) {
         PyErr_SetString(PyExc_TypeError,
@@ -5442,7 +5443,7 @@ Pointer_set_contents(PyObject *myself, PyObject *value, void *closure)
     }
     ctypes_state *st = get_module_state_by_def(Py_TYPE(Py_TYPE(self)));
     StgInfo *stginfo;
-    if (PyStgInfo_FromObject(st, myself, &stginfo) < 0) {
+    if (PyStgInfo_FromObject(st, op, &stginfo) < 0) {
         return -1;
     }
     assert(stginfo); /* Cannot be NULL for pointer instances */
@@ -5664,14 +5665,13 @@ Pointer_subscript(PyObject *myself, PyObject *item)
 }
 
 static int
-Pointer_bool(PyObject *myself)
+Pointer_bool(PyObject *self)
 {
-    CDataObject *self = _CDataObject_CAST(myself);
-    return locked_deref(self) != NULL;
+    return locked_deref(_CDataObject_CAST(self)) != NULL;
 }
 
 static PyType_Slot pycpointer_slots[] = {
-    {Py_tp_doc, PyDoc_STR("XXX to be provided")},
+    {Py_tp_doc, (void *)PyDoc_STR("XXX to be provided")},
     {Py_tp_getset, Pointer_getsets},
     {Py_tp_init, Pointer_init},
     {Py_tp_new, Pointer_new},
diff --git a/Modules/_ctypes/callbacks.c b/Modules/_ctypes/callbacks.c
index 07ccdefaefe2c5..89c0749a093765 100644
--- a/Modules/_ctypes/callbacks.c
+++ b/Modules/_ctypes/callbacks.c
@@ -63,7 +63,7 @@ CThunkObject_dealloc(PyObject *myself)
 }
 
 static PyType_Slot cthunk_slots[] = {
-    {Py_tp_doc, PyDoc_STR("CThunkObject")},
+    {Py_tp_doc, (void *)PyDoc_STR("CThunkObject")},
     {Py_tp_dealloc, CThunkObject_dealloc},
     {Py_tp_traverse, CThunkObject_traverse},
     {Py_tp_clear, CThunkObject_clear},
diff --git a/Modules/_ctypes/cfield.c b/Modules/_ctypes/cfield.c
index 81a660b51b0ffc..0c0a2b4e3bd708 100644
--- a/Modules/_ctypes/cfield.c
+++ b/Modules/_ctypes/cfield.c
@@ -41,7 +41,6 @@ static void pymem_destructor(PyObject *ptr)
 /*
   PyCField_Type
 */
-
 /*[clinic input]
 class _ctypes.CField "PyObject *" "PyObject"
 [clinic start generated code]*/
@@ -308,7 +307,7 @@ static PyType_Slot cfield_slots[] = {
     {Py_tp_new, PyCField_new},
     {Py_tp_dealloc, PyCField_dealloc},
     {Py_tp_repr, PyCField_repr},
-    {Py_tp_doc, PyDoc_STR("Structure/Union member")},
+    {Py_tp_doc, (void *)PyDoc_STR("Structure/Union member")},
     {Py_tp_traverse, PyCField_traverse},
     {Py_tp_clear, PyCField_clear},
     {Py_tp_getset, PyCField_getset},

From a1f7e5ab6f62557a6fdc2915b80c3b77a437f3a0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Mon, 20 Jan 2025 16:40:55 +0100
Subject: [PATCH 11/13] reduce diff even further

---
 Modules/_ctypes/_ctypes.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
index 5c18d41c169b58..c6259865e8177c 100644
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -425,10 +425,11 @@ StructParam_clear(PyObject *myself)
 static void
 StructParam_dealloc(PyObject *myself)
 {
-    PyTypeObject *tp = Py_TYPE(myself);
+    StructParamObject *self = _StructParamObject_CAST(myself);
+    PyTypeObject *tp = Py_TYPE(self);
     PyObject_GC_UnTrack(myself);
     (void)StructParam_clear(myself);
-    PyMem_Free(_StructParamObject_CAST(myself)->ptr);
+    PyMem_Free(self->ptr);
     tp->tp_free(myself);
     Py_DECREF(tp);
 }

From 504eabfa42900193722232d04f219515ab8a1667 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Mon, 20 Jan 2025 17:18:38 +0100
Subject: [PATCH 12/13] keep necessary cast

---
 Modules/_ctypes/_ctypes.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
index c6259865e8177c..e66a2a966b4414 100644
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -5763,7 +5763,7 @@ comerror_dealloc(PyObject *self)
 }
 
 static PyType_Slot comerror_slots[] = {
-    {Py_tp_doc, PyDoc_STR(comerror_doc)},
+    {Py_tp_doc, (void *)PyDoc_STR(comerror_doc)},
     {Py_tp_init, comerror_init},
     {Py_tp_traverse, comerror_traverse},
     {Py_tp_dealloc, comerror_dealloc},

From 1e51fa720c242f2e272d70ff7617550d22a551a1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Mon, 20 Jan 2025 17:31:13 +0100
Subject: [PATCH 13/13] add some new lines

---
 Modules/_ctypes/ctypes.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Modules/_ctypes/ctypes.h b/Modules/_ctypes/ctypes.h
index 55d071a33d74d9..25d337f2ff98ea 100644
--- a/Modules/_ctypes/ctypes.h
+++ b/Modules/_ctypes/ctypes.h
@@ -179,6 +179,7 @@ typedef struct {
     ffi_type *ffi_restype;
     ffi_type *atypes[1];
 } CThunkObject;
+
 #define _CThunkObject_CAST(op)          ((CThunkObject *)(op))
 #define CThunk_CheckExact(st, v)        Py_IS_TYPE(v, st->PyCThunk_Type)
 
@@ -212,6 +213,7 @@ typedef struct {
 #endif
     PyObject *paramflags;
 } PyCFuncPtrObject;
+
 #define _PyCFuncPtrObject_CAST(op)  ((PyCFuncPtrObject *)(op))
 
 extern int PyCStructUnionType_update_stginfo(PyObject *fields, PyObject *type, int isStruct);
@@ -273,6 +275,7 @@ typedef struct CFieldObject {
 
     PyObject *name;                     /* exact PyUnicode */
 } CFieldObject;
+
 #define _CFieldObject_CAST(op)  ((CFieldObject *)(op))
 
 /****************************************************************
@@ -410,6 +413,7 @@ struct tagPyCArgObject {
     PyObject *obj;
     Py_ssize_t size; /* for the 'V' tag */
 };
+
 #define _PyCArgObject_CAST(op)  ((PyCArgObject *)(op))
 
 #define PyCArg_CheckExact(st, v)        Py_IS_TYPE(v, st->PyCArg_Type)