python
@@ -8,6 +8,7 @@ extern "C" {
 #  error "this header requires Py_BUILD_CORE define"
 #endif
 
+#include "pycore_pythonrun.h"     // _PyOS_STACK_MARGIN_SHIFT
 #include "pycore_typedefs.h"      // _PyRuntimeState
 #include "pycore_tstate.h"
 
@@ -325,7 +326,7 @@ _Py_RecursionLimit_GetMargin(PyThreadState *tstate)
     _PyThreadStateImpl *_tstate = (_PyThreadStateImpl *)tstate;
     assert(_tstate->c_stack_hard_limit != 0);
     intptr_t here_addr = _Py_get_machine_stack_pointer();
-    return Py_ARITHMETIC_RIGHT_SHIFT(intptr_t, here_addr - (intptr_t)_tstate->c_stack_soft_limit, PYOS_STACK_MARGIN_SHIFT);
+    return Py_ARITHMETIC_RIGHT_SHIFT(intptr_t, here_addr - (intptr_t)_tstate->c_stack_soft_limit, _PyOS_STACK_MARGIN_SHIFT);
 }
 
 #ifdef __cplusplus

@@ -33,6 +33,28 @@ extern const char* _Py_SourceAsString(
     PyCompilerFlags *cf,
     PyObject **cmd_copy);
 
+
+/* Stack size, in "pointers". This must be large enough, so
+ * no two calls to check recursion depth are more than this far
+ * apart. In practice, that means it must be larger than the C
+ * stack consumption of PyEval_EvalDefault */
+#if defined(_Py_ADDRESS_SANITIZER) || defined(_Py_THREAD_SANITIZER)
+#  define _PyOS_LOG2_STACK_MARGIN 12
+#elif defined(Py_DEBUG) && defined(WIN32)
+#  define _PyOS_LOG2_STACK_MARGIN 12
+#else
+#  define _PyOS_LOG2_STACK_MARGIN 11
+#endif
+#define _PyOS_STACK_MARGIN (1 << _PyOS_LOG2_STACK_MARGIN)
+#define _PyOS_STACK_MARGIN_BYTES (_PyOS_STACK_MARGIN * sizeof(void *))
+
+#if SIZEOF_VOID_P == 8
+#  define _PyOS_STACK_MARGIN_SHIFT (_PyOS_LOG2_STACK_MARGIN + 3)
+#else
+#  define _PyOS_STACK_MARGIN_SHIFT (_PyOS_LOG2_STACK_MARGIN + 2)
+#endif
+
+
 #ifdef __cplusplus
 }
 #endif

@@ -21,36 +21,15 @@ PyAPI_FUNC(void) PyErr_DisplayException(PyObject *);
 /* Stuff with no proper home (yet) */
 PyAPI_DATA(int) (*PyOS_InputHook)(void);
 
-/* Stack size, in "pointers". This must be large enough, so
- * no two calls to check recursion depth are more than this far
- * apart. In practice, that means it must be larger than the C
- * stack consumption of PyEval_EvalDefault */
-#if defined(_Py_ADDRESS_SANITIZER) || defined(_Py_THREAD_SANITIZER)
-#  define PYOS_LOG2_STACK_MARGIN 12
-#elif defined(Py_DEBUG) && defined(WIN32)
-#  define PYOS_LOG2_STACK_MARGIN 12
-#else
-#  define PYOS_LOG2_STACK_MARGIN 11
-#endif
-#define PYOS_STACK_MARGIN (1 << PYOS_LOG2_STACK_MARGIN)
-#define PYOS_STACK_MARGIN_BYTES (PYOS_STACK_MARGIN * sizeof(void *))
-
-#if SIZEOF_VOID_P == 8
-#define PYOS_STACK_MARGIN_SHIFT (PYOS_LOG2_STACK_MARGIN + 3)
-#else
-#define PYOS_STACK_MARGIN_SHIFT (PYOS_LOG2_STACK_MARGIN + 2)
-#endif
-
-
 #if defined(WIN32)
-#define USE_STACKCHECK
+#  define USE_STACKCHECK
 #endif
-
 #ifdef USE_STACKCHECK
 /* Check that we aren't overflowing our stack */
 PyAPI_FUNC(int) PyOS_CheckStack(void);
 #endif
 
+
 #ifndef Py_LIMITED_API
 #  define Py_CPYTHON_PYTHONRUN_H
 #  include "cpython/pythonrun.h"

diff --git a/Modules/_testinternalcapi.c b/Modules/_testinternalcapi.c
@@ -120,7 +120,7 @@ get_c_recursion_remaining(PyObject *self, PyObject *Py_UNUSED(args))
     PyThreadState *tstate = _PyThreadState_GET();
     uintptr_t here_addr = _Py_get_machine_stack_pointer();
     _PyThreadStateImpl *_tstate = (_PyThreadStateImpl *)tstate;
-    int remaining = (int)((here_addr - _tstate->c_stack_soft_limit)/PYOS_STACK_MARGIN_BYTES * 50);
+    int remaining = (int)((here_addr - _tstate->c_stack_soft_limit) / _PyOS_STACK_MARGIN_BYTES * 50);
     return PyLong_FromLong(remaining);
 }
 

@@ -346,13 +346,13 @@ _Py_ReachedRecursionLimitWithMargin(PyThreadState *tstate, int margin_count)
 {
     uintptr_t here_addr = _Py_get_machine_stack_pointer();
     _PyThreadStateImpl *_tstate = (_PyThreadStateImpl *)tstate;
-    if (here_addr > _tstate->c_stack_soft_limit + margin_count * PYOS_STACK_MARGIN_BYTES) {
+    if (here_addr > _tstate->c_stack_soft_limit + margin_count * _PyOS_STACK_MARGIN_BYTES) {
         return 0;
     }
     if (_tstate->c_stack_hard_limit == 0) {
         _Py_InitializeRecursionLimits(tstate);
     }
-    return here_addr <= _tstate->c_stack_soft_limit + margin_count * PYOS_STACK_MARGIN_BYTES;
+    return here_addr <= _tstate->c_stack_soft_limit + margin_count * _PyOS_STACK_MARGIN_BYTES;
 }
 
 void
@@ -448,8 +448,8 @@ _Py_InitializeRecursionLimits(PyThreadState *tstate)
     _tstate->c_stack_top = (uintptr_t)high;
     ULONG guarantee = 0;
     SetThreadStackGuarantee(&guarantee);
-    _tstate->c_stack_hard_limit = ((uintptr_t)low) + guarantee + PYOS_STACK_MARGIN_BYTES;
-    _tstate->c_stack_soft_limit = _tstate->c_stack_hard_limit + PYOS_STACK_MARGIN_BYTES;
+    _tstate->c_stack_hard_limit = ((uintptr_t)low) + guarantee + _PyOS_STACK_MARGIN_BYTES;
+    _tstate->c_stack_soft_limit = _tstate->c_stack_hard_limit + _PyOS_STACK_MARGIN_BYTES;
 #else
     uintptr_t here_addr = _Py_get_machine_stack_pointer();
 #  if defined(HAVE_PTHREAD_GETATTR_NP) && !defined(_AIX) && !defined(__NetBSD__)
@@ -469,17 +469,17 @@ _Py_InitializeRecursionLimits(PyThreadState *tstate)
         // Thread sanitizer crashes if we use a bit more than half the stack.
         _tstate->c_stack_soft_limit = base + (stack_size / 2);
 #else
-        _tstate->c_stack_soft_limit = base + PYOS_STACK_MARGIN_BYTES * 2;
+        _tstate->c_stack_soft_limit = base + _PyOS_STACK_MARGIN_BYTES * 2;
 #endif
-        _tstate->c_stack_hard_limit = base + PYOS_STACK_MARGIN_BYTES;
+        _tstate->c_stack_hard_limit = base + _PyOS_STACK_MARGIN_BYTES;
         assert(_tstate->c_stack_soft_limit < here_addr);
         assert(here_addr < _tstate->c_stack_top);
         return;
     }
 #  endif
     _tstate->c_stack_top = _Py_SIZE_ROUND_UP(here_addr, 4096);
     _tstate->c_stack_soft_limit = _tstate->c_stack_top - Py_C_STACK_SIZE;
-    _tstate->c_stack_hard_limit = _tstate->c_stack_top - (Py_C_STACK_SIZE + PYOS_STACK_MARGIN_BYTES);
+    _tstate->c_stack_hard_limit = _tstate->c_stack_top - (Py_C_STACK_SIZE + _PyOS_STACK_MARGIN_BYTES);
 #endif
 }