GH-126910: avoid reading the FP for getting the SP (GH-146521)

Include/internal/pycore_pystate.h

diff --git a/Include/internal/pycore_pystate.h b/Include/internal/pycore_pystate.h
index 189a8dd..a66543c 100644
--- a/Include/internal/pycore_pystate.h
+++ b/Include/internal/pycore_pystate.h
@@ -312,18 +312,7 @@ static uintptr_t return_pointer_as_int(char* p) {
 }
 #endif
 
-static inline uintptr_t
-_Py_get_machine_stack_pointer(void) {
-#if _Py__has_builtin(__builtin_frame_address) || defined(__GNUC__)
-    return (uintptr_t)__builtin_frame_address(0);
-#elif defined(_MSC_VER)
-    return (uintptr_t)_AddressOfReturnAddress();
-#else
-    char here;
-    /* Avoid compiler warning about returning stack address */
-    return return_pointer_as_int(&here);
-#endif
-}
+PyAPI_DATA(uintptr_t) _Py_get_machine_stack_pointer(void);
 
 static inline intptr_t
 _Py_RecursionLimit_GetMargin(PyThreadState *tstate)

Python/pystate.c

diff --git a/Python/pystate.c b/Python/pystate.c
index 143175d..f974c82 100644
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -3286,3 +3286,16 @@ _Py_GetMainConfig(void)
     }
     return _PyInterpreterState_GetConfig(interp);
 }
+
+uintptr_t
+_Py_get_machine_stack_pointer(void) {
+#if _Py__has_builtin(__builtin_frame_address) || defined(__GNUC__)
+    return (uintptr_t)__builtin_frame_address(0);
+#elif defined(_MSC_VER)
+    return (uintptr_t)_AddressOfReturnAddress();
+#else
+    char here;
+    /* Avoid compiler warning about returning stack address */
+    return return_pointer_as_int(&here);
+#endif
+}