Refactor a bit

Author: markshannon

Include/internal/pycore_ceval.h

@@ -222,7 +222,7 @@ static inline void _Py_LeaveRecursiveCallTstate(PyThreadState *tstate) {
     (void)tstate;
 }
 
-PyAPI_FUNC(void) _Py_UpdateRecursionLimits(PyThreadState *tstate);
+PyAPI_FUNC(void) _Py_InitializeRecursionLimits(PyThreadState *tstate);
 
 static inline int _Py_ReachedRecursionLimit(PyThreadState *tstate, int margin_count)  {
     char here;
@@ -231,7 +231,7 @@ static inline int _Py_ReachedRecursionLimit(PyThreadState *tstate, int margin_co
         return 0;
     }
     if (tstate->c_stack_hard_limit == 0) {
-        _Py_UpdateRecursionLimits(tstate);
+        _Py_InitializeRecursionLimits(tstate);
     }
     return here_addr <= tstate->c_stack_soft_limit + margin_count * PYOS_STACK_MARGIN_BYTES;
 }
@@ -327,8 +327,6 @@ void _Py_unset_eval_breaker_bit_all(PyInterpreterState *interp, uintptr_t bit);
 
 PyAPI_FUNC(PyObject *) _PyFloat_FromDouble_ConsumeInputs(_PyStackRef left, _PyStackRef right, double value);
 
-extern void _Py_StackProbe(uintptr_t from, int bytes, int *probed);
-
 #ifdef __cplusplus
 }
 #endif

Python/ceval.c

@@ -323,7 +323,7 @@ _Py_EnterRecursiveCallUnchecked(PyThreadState *tstate)
 #if defined(__s390x__)
 #  define Py_C_STACK_SIZE 320000
 #elif defined(_WIN32)
-   // Don't define Py_C_STACK_SIZE, use probing instead
+   // Don't define Py_C_STACK_SIZE, ask the O/S
 #elif defined(__ANDROID__)
 #  define Py_C_STACK_SIZE 1200000
 #elif defined(__sparc__)
@@ -340,7 +340,7 @@ _Py_EnterRecursiveCallUnchecked(PyThreadState *tstate)
 #endif
 
 void
-_Py_UpdateRecursionLimits(PyThreadState *tstate)
+_Py_InitializeRecursionLimits(PyThreadState *tstate)
 {
 #ifdef WIN32
     ULONG_PTR low, high;
@@ -368,7 +368,7 @@ _Py_CheckRecursiveCall(PyThreadState *tstate, const char *where)
     uintptr_t here_addr = (uintptr_t)&here;
     assert(tstate->c_stack_soft_limit != 0);
     if (tstate->c_stack_hard_limit == 0) {
-        _Py_UpdateRecursionLimits(tstate);
+        _Py_InitializeRecursionLimits(tstate);
     }
     if (here_addr >= tstate->c_stack_soft_limit) {
         return 0;

Python/pythonrun.c

@@ -1552,47 +1552,18 @@ _Py_SourceAsString(PyObject *cmd, const char *funcname, const char *what, PyComp
 #include <malloc.h>
 #include <excpt.h>
 
-void _Py_StackProbe(uintptr_t from, int bytes, int *probed)
-{
-    assert((bytes & 4095) == 0);
-    int depth = 4096;
-    char here;
-    uintptr_t here_addr = (uintptr_t)&here;
-    __try
-    {
-        while (depth <= bytes) {
-            uintptr_t probe_point = from - depth + 64;
-            if (probe_point < here_addr) {
-                /* alloca throws a stack overflow exception if there's
-                 * not enough space left on the stack */
-                alloca(here_addr - probe_point);
-            }
-            *probed = depth;
-            depth += 4096;
-        }
-    }
-    __except (GetExceptionCode() == STATUS_STACK_OVERFLOW ? EXCEPTION_EXECUTE_HANDLER : EXCEPTION_CONTINUE_SEARCH)
-    {
-        int errcode = _resetstkoflw();
-        if (errcode == 0)
-        {
-            Py_FatalError("Could not reset the stack!");
-        }
-    }
-}
-
 /*
  * Return non-zero when we run out of memory on the stack; zero otherwise.
  */
 int PyOS_CheckStack(void)
 {
     char here;
     uintptr_t here_addr = (uintptr_t)&here;
-    uintptr_t from = _Py_SIZE_ROUND_UP(here_addr, 4096);
-    int depth;
-    _Py_StackProbe(from, PYOS_STACK_MARGIN_BYTES*2, &depth);
-    assert(depth <= PYOS_STACK_MARGIN_BYTES*2);
-    if (depth == PYOS_STACK_MARGIN_BYTES*2) {
+    PyThreadState *tstate = _PyThreadState_GET();
+    if (tstate->c_stack_hard_limit == 0) {
+        _Py_InitializeRecursionLimits(tstate);
+    }
+    if (here_addr >= tstate->c_stack_soft_limit) {
         return 0;
     }
     else {