https://github.com/python/cpython/commit/056c08211b402b4dbc1530a9de9d00ad530... commit: 056c08211b402b4dbc1530a9de9d00ad5309909f branch: master author: Petr Viktorin <encukou@gmail.com> committer: miss-islington <31488909+miss-islington@users.noreply.github.com> date: 2020-12-29T15:32:07-08:00 summary: bpo-40052: Fix alignment issue in PyVectorcall_Function() (GH-23999) ``` In file included from /usr/include/python3.8/Python.h:147: In file included from /usr/include/python3.8/abstract.h:837: /usr/include/python3.8/cpython/abstract.h:91:11: error: cast from 'char *' to 'vectorcallfunc *' (aka 'struct _object *(**)(struct _object *, struct _object *const *, unsigned long, struct _object *)') increases required alignment from 1 to 8 [-Werror,-Wcast-align] ptr = (vectorcallfunc*)(((char *)callable) + offset); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1 error generated. ``` Co-Authored-By: Andreas Schneider <asn@cryptomilk.org> Co-Authored-By: Antoine Pitrou <antoine@python.org> files: A Misc/NEWS.d/next/C API/2020-03-24-09-27-10.bpo-40052.27P2KG.rst M Include/cpython/abstract.h M Objects/call.c diff --git a/Include/cpython/abstract.h b/Include/cpython/abstract.h index b5b6e4819788c..1083942c14929 100644 --- a/Include/cpython/abstract.h +++ b/Include/cpython/abstract.h @@ -63,7 +63,7 @@ PyVectorcall_Function(PyObject *callable) { PyTypeObject *tp; Py_ssize_t offset; - vectorcallfunc *ptr; + vectorcallfunc ptr; assert(callable != NULL); tp = Py_TYPE(callable); @@ -73,8 +73,8 @@ PyVectorcall_Function(PyObject *callable) assert(PyCallable_Check(callable)); offset = tp->tp_vectorcall_offset; assert(offset > 0); - ptr = (vectorcallfunc *)(((char *)callable) + offset); - return *ptr; + memcpy(&ptr, (char *) callable + offset, sizeof(ptr)); + return ptr; } /* Call the callable object 'callable' with the "vectorcall" calling diff --git a/Misc/NEWS.d/next/C API/2020-03-24-09-27-10.bpo-40052.27P2KG.rst b/Misc/NEWS.d/next/C API/2020-03-24-09-27-10.bpo-40052.27P2KG.rst new file mode 100644 index 0000000000000..538488e2fbacc --- /dev/null +++ b/Misc/NEWS.d/next/C API/2020-03-24-09-27-10.bpo-40052.27P2KG.rst @@ -0,0 +1,2 @@ +Fix an alignment build warning/error in function ``PyVectorcall_Function()``. +Patch by Andreas Schneider, Antoine Pitrou and Petr Viktorin. diff --git a/Objects/call.c b/Objects/call.c index 30fa14ccfd765..35b06a9b9c4d7 100644 --- a/Objects/call.c +++ b/Objects/call.c @@ -205,6 +205,7 @@ PyObject * PyVectorcall_Call(PyObject *callable, PyObject *tuple, PyObject *kwargs) { PyThreadState *tstate = _PyThreadState_GET(); + vectorcallfunc func; /* get vectorcallfunc as in PyVectorcall_Function, but without * the Py_TPFLAGS_HAVE_VECTORCALL check */ @@ -215,7 +216,7 @@ PyVectorcall_Call(PyObject *callable, PyObject *tuple, PyObject *kwargs) Py_TYPE(callable)->tp_name); return NULL; } - vectorcallfunc func = *(vectorcallfunc *)(((char *)callable) + offset); + memcpy(&func, (char *) callable + offset, sizeof(func)); if (func == NULL) { _PyErr_Format(tstate, PyExc_TypeError, "'%.200s' object does not support vectorcall",