WIP: gh-115754: Get singletons via function calls

Author: vstinner

Include/boolobject.h

@@ -17,9 +17,10 @@ extern "C" {
 PyAPI_DATA(PyLongObject) _Py_FalseStruct;
 PyAPI_DATA(PyLongObject) _Py_TrueStruct;
 
-/* Use these macros */
-#define Py_False _PyObject_CAST(&_Py_FalseStruct)
-#define Py_True _PyObject_CAST(&_Py_TrueStruct)
+PyAPI_FUNC(PyObject*) Py_GetFalse(void);
+PyAPI_FUNC(PyObject*) Py_GetTrue(void);
+#define Py_False Py_GetFalse()
+#define Py_True Py_GetTrue()
 
 // Test if an object is the True singleton, the same as "x is True" in Python.
 PyAPI_FUNC(int) Py_IsTrue(PyObject *x);

Include/object.h

@@ -1070,7 +1070,8 @@ _Py_NoneStruct is an object of undefined type which can be used in contexts
 where NULL (nil) is not suitable (since NULL often means 'error').
 */
 PyAPI_DATA(PyObject) _Py_NoneStruct; /* Don't use this directly */
-#define Py_None (&_Py_NoneStruct)
+PyAPI_FUNC(PyObject*) Py_GetNone(void);
+#define Py_None Py_GetNone()
 
 // Test if an object is the None singleton, the same as "x is None" in Python.
 PyAPI_FUNC(int) Py_IsNone(PyObject *x);
@@ -1084,7 +1085,8 @@ Py_NotImplemented is a singleton used to signal that an operation is
 not implemented for a given type combination.
 */
 PyAPI_DATA(PyObject) _Py_NotImplementedStruct; /* Don't use this directly */
-#define Py_NotImplemented (&_Py_NotImplementedStruct)
+PyAPI_FUNC(PyObject*) Py_GetNotImplemented(void);
+#define Py_NotImplemented Py_GetNotImplemented()
 
 /* Macro for returning Py_NotImplemented from a function */
 #define Py_RETURN_NOTIMPLEMENTED return Py_NotImplemented

Include/sliceobject.h

@@ -8,7 +8,8 @@ extern "C" {
 
 PyAPI_DATA(PyObject) _Py_EllipsisObject; /* Don't use this directly */
 
-#define Py_Ellipsis (&_Py_EllipsisObject)
+PyAPI_FUNC(PyObject*) Py_GetEllipsis(void);
+#define Py_Ellipsis Py_GetEllipsis()
 
 /* Slice object interface */
 

Objects/longobject.c

@@ -6605,3 +6605,9 @@ Py_ssize_t
 PyUnstable_Long_CompactValue(const PyLongObject* op) {
     return _PyLong_CompactValue(op);
 }
+
+PyObject* Py_GetFalse(void)
+{ return _PyObject_CAST(&_Py_FalseStruct); }
+
+PyObject* Py_GetTrue(void)
+{ return _PyObject_CAST(&_Py_TrueStruct); }

Objects/object.c

@@ -2970,3 +2970,9 @@ _Py_SetRefcnt(PyObject *ob, Py_ssize_t refcnt)
 {
     Py_SET_REFCNT(ob, refcnt);
 }
+
+PyObject* Py_GetNone(void)
+{ return &_Py_NoneStruct; }
+
+PyObject* Py_GetNotImplemented(void)
+{ return &_Py_NotImplementedStruct; }

Objects/sliceobject.c

@@ -721,3 +721,6 @@ PyTypeObject PySlice_Type = {
     0,                                          /* tp_alloc */
     slice_new,                                  /* tp_new */
 };
+
+PyObject* Py_GetEllipsis(void)
+{ return &_Py_EllipsisObject; }