gh-117323: Make cell thread-safe in free-threaded builds (#117330)

Use critical sections to lock around accesses to cell contents. The critical sections are no-ops in the default (with GIL) build.
This commit is contained in:
Sam Gross 2024-03-29 13:35:43 -04:00 committed by GitHub
parent 397d88db5e
commit 19c1dd60c5
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GPG key ID: B5690EEEBB952194
11 changed files with 83 additions and 43 deletions

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@ -1362,14 +1362,13 @@
case _DELETE_DEREF: {
oparg = CURRENT_OPARG();
PyObject *cell = GETLOCAL(oparg);
PyObject *oldobj = PyCell_GET(cell);
// Can't use ERROR_IF here.
// Fortunately we don't need its superpower.
PyObject *oldobj = PyCell_SwapTakeRef((PyCellObject *)cell, NULL);
if (oldobj == NULL) {
_PyEval_FormatExcUnbound(tstate, _PyFrame_GetCode(frame), oparg);
JUMP_TO_ERROR();
}
PyCell_SET(cell, NULL);
Py_DECREF(oldobj);
break;
}
@ -1387,13 +1386,12 @@
JUMP_TO_ERROR();
}
if (!value) {
PyObject *cell = GETLOCAL(oparg);
value = PyCell_GET(cell);
PyCellObject *cell = (PyCellObject *)GETLOCAL(oparg);
value = PyCell_GetRef(cell);
if (value == NULL) {
_PyEval_FormatExcUnbound(tstate, _PyFrame_GetCode(frame), oparg);
JUMP_TO_ERROR();
}
Py_INCREF(value);
}
Py_DECREF(class_dict);
stack_pointer[-1] = value;
@ -1403,13 +1401,12 @@
case _LOAD_DEREF: {
PyObject *value;
oparg = CURRENT_OPARG();
PyObject *cell = GETLOCAL(oparg);
value = PyCell_GET(cell);
PyCellObject *cell = (PyCellObject *)GETLOCAL(oparg);
value = PyCell_GetRef(cell);
if (value == NULL) {
_PyEval_FormatExcUnbound(tstate, _PyFrame_GetCode(frame), oparg);
if (true) JUMP_TO_ERROR();
}
Py_INCREF(value);
stack_pointer[0] = value;
stack_pointer += 1;
break;
@ -1419,10 +1416,8 @@
PyObject *v;
oparg = CURRENT_OPARG();
v = stack_pointer[-1];
PyObject *cell = GETLOCAL(oparg);
PyObject *oldobj = PyCell_GET(cell);
PyCell_SET(cell, v);
Py_XDECREF(oldobj);
PyCellObject *cell = (PyCellObject *)GETLOCAL(oparg);
PyCell_SetTakeRef(cell, v);
stack_pointer += -1;
break;
}