Skip to content

gh-98724: Fix type punning issue in Py_SETREF() #99739

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
vstinner wants to merge 1 commit into from
Closed

gh-98724: Fix type punning issue in Py_SETREF() #99739

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
gh-98724: Fix type punning issue in Py_SETREF() 
Fix type punning issue in Py_CLEAR(), Py_SETREF() and Py_XSETREF()
macros. Don't cast pointers to avoid type punning which cause
miscompilation of functions using these macros.
  • Loading branch information
@vstinner
vstinner committed Nov 23, 2022
commit 822d5663cada64a1fe4b394f9b5d05859f432799
12 changes: 6 additions & 6 deletions Include/cpython/object.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -325,9 +325,9 @@ PyAPI_FUNC(PyObject *) _PyObject_FunctionStr(PyObject *);
*/
#define Py_SETREF(dst, src) \
do { \
PyObject **_tmp_dst_ptr = _Py_CAST(PyObject**, &(dst)); \
PyObject *_tmp_dst = (*_tmp_dst_ptr); \
*_tmp_dst_ptr = _PyObject_CAST(src); \
_PY_TYPEOF(dst)* _tmp_dst_ptr = &(dst); \
_PY_TYPEOF(dst) _tmp_dst = *_tmp_dst_ptr; \
*_tmp_dst_ptr = (src); \
Py_DECREF(_tmp_dst); \
} while (0)

Expand All @@ -336,9 +336,9 @@ PyAPI_FUNC(PyObject *) _PyObject_FunctionStr(PyObject *);
*/
#define Py_XSETREF(dst, src) \
do { \
PyObject **_tmp_dst_ptr = _Py_CAST(PyObject**, &(dst)); \
PyObject *_tmp_dst = (*_tmp_dst_ptr); \
*_tmp_dst_ptr = _PyObject_CAST(src); \
_PY_TYPEOF(dst)* _tmp_dst_ptr = &(dst); \
_PY_TYPEOF(dst) _tmp_dst = *_tmp_dst_ptr; \
*_tmp_dst_ptr = (src); \
Py_XDECREF(_tmp_dst); \
} while (0)

Expand Down
4 changes: 2 additions & 2 deletions Include/object.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -604,9 +604,9 @@ static inline void Py_DECREF(PyObject *op)
*/
#define Py_CLEAR(op) \
do { \
PyObject **_py_tmp_ptr = _Py_CAST(PyObject**, &(op)); \
_PY_TYPEOF(op)* _py_tmp_ptr = &(op); \
if (*_py_tmp_ptr != NULL) { \
PyObject* _py_tmp = (*_py_tmp_ptr); \
_PY_TYPEOF(op) _py_tmp = *_py_tmp_ptr; \
*_py_tmp_ptr = NULL; \
Py_DECREF(_py_tmp); \
} \
Expand Down
3 changes: 3 additions & 0 deletions Include/pyport.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -717,4 +717,7 @@ extern char * _getpty(int *, int, mode_t, int);
# endif
#endif

// Get the type of an expression
#define _PY_TYPEOF(EXPR) __typeof__(EXPR)

#endif /* Py_PYPORT_H */