GH-91079: Decouple C stack overflow checks from Python recursion checks. (GH-96510)

3 files changed, 24 insertions, 15 deletions

diff --git a/Include/cpython/pystate.h b/Include/cpython/pystate.h
index cc3c3ea..7722a38 100644
--- a/Include/cpython/pystate.h
+++ b/Include/cpython/pystate.h
@@ -95,8 +95,10 @@ struct _ts {
     /* Was this thread state statically allocated? */
     int _static;
 
-    int recursion_remaining;
-    int recursion_limit;
+    int py_recursion_remaining;
+    int py_recursion_limit;
+
+    int c_recursion_remaining;
     int recursion_headroom; /* Allow 50 more calls to handle any errors. */
 
     /* 'tracing' keeps track of the execution depth when tracing/profiling.
@@ -202,6 +204,16 @@ struct _ts {
     _PyCFrame root_cframe;
 };
 
+/* WASI has limited call stack. Python's recursion limit depends on code
+   layout, optimization, and WASI runtime. Wasmtime can handle about 700
+   recursions, sometimes less. 500 is a more conservative limit. */
+#ifndef C_RECURSION_LIMIT
+#  ifdef __wasi__
+#    define C_RECURSION_LIMIT 500
+#  else
+#    define C_RECURSION_LIMIT 800
+#  endif
+#endif
 
 /* other API */
 
diff --git a/Include/internal/pycore_ceval.h b/Include/internal/pycore_ceval.h
index 4914948c..deda070 100644
--- a/Include/internal/pycore_ceval.h
+++ b/Include/internal/pycore_ceval.h
@@ -12,15 +12,8 @@ extern "C" {
 struct pyruntimestate;
 struct _ceval_runtime_state;
 
-/* WASI has limited call stack. Python's recursion limit depends on code
-   layout, optimization, and WASI runtime. Wasmtime can handle about 700-750
-   recursions, sometimes less. 600 is a more conservative limit. */
 #ifndef Py_DEFAULT_RECURSION_LIMIT
-#  ifdef __wasi__
-#    define Py_DEFAULT_RECURSION_LIMIT 600
-#  else
-#    define Py_DEFAULT_RECURSION_LIMIT 1000
-#  endif
+#  define Py_DEFAULT_RECURSION_LIMIT 1000
 #endif
 
 #include "pycore_interp.h"        // PyInterpreterState.eval_frame
@@ -118,12 +111,12 @@ extern void _PyEval_DeactivateOpCache(void);
 /* With USE_STACKCHECK macro defined, trigger stack checks in
    _Py_CheckRecursiveCall() on every 64th call to _Py_EnterRecursiveCall. */
 static inline int _Py_MakeRecCheck(PyThreadState *tstate)  {
-    return (tstate->recursion_remaining-- <= 0
-            || (tstate->recursion_remaining & 63) == 0);
+    return (tstate->c_recursion_remaining-- <= 0
+            || (tstate->c_recursion_remaining & 63) == 0);
 }
 #else
 static inline int _Py_MakeRecCheck(PyThreadState *tstate) {
-    return tstate->recursion_remaining-- <= 0;
+    return tstate->c_recursion_remaining-- <= 0;
 }
 #endif
 
@@ -131,6 +124,9 @@ PyAPI_FUNC(int) _Py_CheckRecursiveCall(
     PyThreadState *tstate,
     const char *where);
 
+int _Py_CheckRecursiveCallPy(
+    PyThreadState *tstate);
+
 static inline int _Py_EnterRecursiveCallTstate(PyThreadState *tstate,
                                                const char *where) {
     return (_Py_MakeRecCheck(tstate) && _Py_CheckRecursiveCall(tstate, where));
@@ -142,7 +138,7 @@ static inline int _Py_EnterRecursiveCall(const char *where) {
 }
 
 static inline void _Py_LeaveRecursiveCallTstate(PyThreadState *tstate)  {
-    tstate->recursion_remaining++;
+    tstate->c_recursion_remaining++;
 }
 
 static inline void _Py_LeaveRecursiveCall(void)  {
@@ -157,6 +153,7 @@ extern PyObject* _Py_MakeCoro(PyFunctionObject *func);
 extern int _Py_HandlePending(PyThreadState *tstate);
 
 
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/Include/internal/pycore_runtime_init.h b/Include/internal/pycore_runtime_init.h
index 621d5cc..8dd7a31 100644
--- a/Include/internal/pycore_runtime_init.h
+++ b/Include/internal/pycore_runtime_init.h
@@ -68,7 +68,7 @@ extern "C" {
 #define _PyThreadState_INIT \
     { \
         ._static = 1, \
-        .recursion_limit = Py_DEFAULT_RECURSION_LIMIT, \
+        .py_recursion_limit = Py_DEFAULT_RECURSION_LIMIT, \
         .context_ver = 1, \
     }