pythongh-111506: Implement Py_SET_REFCNT() as inline function

Convert Py_SET_REFCNT() and _Py_IsImmortal() static inline functions
to inline functions.

Py_SET_REFCNT() function is now exported as "Py_SET_REFCNT" name in
the stable ABI, instead of "_Py_SetRefcnt".

_Py_IsImmortal() has to be converted to an inline function, since
non-static Py_SET_REFCNT() function cannot call a static
_Py_IsImmortal() function. _Py_IsImmortal() is not part of the stable
ABI.

Include/object.h

@@ -332,7 +332,8 @@ static inline Py_ssize_t Py_SIZE(PyObject *ob) {
 #  define Py_SIZE(ob) Py_SIZE(_PyObject_CAST(ob))
 #endif
 
-static inline Py_ALWAYS_INLINE int _Py_IsImmortal(PyObject *op)
+#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030d0000
+inline Py_ALWAYS_INLINE int _Py_IsImmortal(PyObject *op)
 {
 #if defined(Py_GIL_DISABLED)
     return (op->ob_ref_local == _Py_IMMORTAL_REFCNT_LOCAL);
@@ -343,6 +344,8 @@ static inline Py_ALWAYS_INLINE int _Py_IsImmortal(PyObject *op)
 #endif
 }
 #define _Py_IsImmortal(op) _Py_IsImmortal(_PyObject_CAST(op))
+#endif  // !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030d0000
+
 
 static inline int Py_IS_TYPE(PyObject *ob, PyTypeObject *type) {
     return Py_TYPE(ob) == type;
@@ -352,15 +355,12 @@ static inline int Py_IS_TYPE(PyObject *ob, PyTypeObject *type) {
 #endif
 
 
-// Py_SET_REFCNT() implementation for stable ABI
-PyAPI_FUNC(void) _Py_SetRefcnt(PyObject *ob, Py_ssize_t refcnt);
-
-static inline void Py_SET_REFCNT(PyObject *ob, Py_ssize_t refcnt) {
+// Stable ABI implements Py_SET_REFCNT() as an opaque function call in the
+// limited C API version 3.13 and newer.
 #if defined(Py_LIMITED_API) && Py_LIMITED_API+0 >= 0x030d0000
-    // Stable ABI implements Py_SET_REFCNT() as a function call
-    // on limited C API version 3.13 and newer.
-    _Py_SetRefcnt(ob, refcnt);
+PyAPI_DATA(void) Py_SET_REFCNT(PyObject *ob, Py_ssize_t refcnt);
 #else
+inline void Py_SET_REFCNT(PyObject *ob, Py_ssize_t refcnt) {
     // This immortal check is for code that is unaware of immortal objects.
     // The runtime tracks these objects and we should avoid as much
     // as possible having extensions inadvertently change the refcnt
@@ -394,11 +394,11 @@ static inline void Py_SET_REFCNT(PyObject *ob, Py_ssize_t refcnt) {
         ob->ob_ref_shared = _Py_REF_SHARED(refcnt, _Py_REF_MERGED);
     }
 #endif  // Py_GIL_DISABLED
-#endif  // Py_LIMITED_API+0 < 0x030d0000
 }
 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
 #  define Py_SET_REFCNT(ob, refcnt) Py_SET_REFCNT(_PyObject_CAST(ob), (refcnt))
 #endif
+#endif  // !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030d0000
 
 
 static inline void Py_SET_TYPE(PyObject *ob, PyTypeObject *type) {

Misc/stable_abi.toml

@@ -2478,6 +2478,5 @@
     added = '3.13'
 [function.PySys_AuditTuple]
     added = '3.13'
-[function._Py_SetRefcnt]
+[function.Py_SET_REFCNT]
     added = '3.13'
-    abi_only = true

Objects/object.c

@@ -2938,3 +2938,11 @@ _Py_SetRefcnt(PyObject *ob, Py_ssize_t refcnt)
 {
     Py_SET_REFCNT(ob, refcnt);
 }
+
+// Export _Py_IsImmortal() as a regular function
+#undef _Py_IsImmortal
+extern inline PyAPI_FUNC(int) _Py_IsImmortal(PyObject *op);
+
+// Export Py_SET_REFCNT() as a regular function in stable ABI
+#undef Py_SET_REFCNT
+extern inline PyAPI_FUNC(void) Py_SET_REFCNT(PyObject *ob, Py_ssize_t refcnt);