Deleting cyclic object comparison.

SF patch 825639
http://mail.python.org/pipermail/python-dev/2003-October/039445.html

1 files changed, 36 insertions, 20 deletions

diff --git a/Python/ceval.c b/Python/ceval.c
index e6b7424..fe8aca5 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -497,6 +497,7 @@ Py_MakePendingCalls(void)
 /* The interpreter's recursion limit */
 
 static int recursion_limit = 1000;
+int _Py_CheckRecursionLimit = 1000;
 
 int
 Py_GetRecursionLimit(void)
@@ -508,8 +509,38 @@ void
 Py_SetRecursionLimit(int new_limit)
 {
 	recursion_limit = new_limit;
+        _Py_CheckRecursionLimit = recursion_limit;
 }
 
+/* the macro Py_EnterRecursiveCall() only calls _Py_CheckRecursiveCall()
+   if the recursion_depth reaches _Py_CheckRecursionLimit.
+   If USE_STACKCHECK, the macro decrements _Py_CheckRecursionLimit
+   to guarantee that _Py_CheckRecursiveCall() is regularly called.
+   Without USE_STACKCHECK, there is no need for this. */
+int
+_Py_CheckRecursiveCall(char *where)
+{
+	PyThreadState *tstate = PyThreadState_GET();
+
+#ifdef USE_STACKCHECK
+	if (PyOS_CheckStack()) {
+		--tstate->recursion_depth;
+		PyErr_SetString(PyExc_MemoryError, "Stack overflow");
+		return -1;
+	}
+#endif
+	if (tstate->recursion_depth > recursion_limit) {
+		--tstate->recursion_depth;
+		PyErr_Format(PyExc_RuntimeError,
+			     "maximum recursion depth exceeded%s",
+			     where);
+		return -1;
+	}
+        _Py_CheckRecursionLimit = recursion_limit;
+	return 0;
+}
+
+
 /* Status code for main loop (reason for stack unwind) */
 
 enum why_code {
@@ -674,21 +705,9 @@ eval_frame(PyFrameObject *f)
 	if (f == NULL)
 		return NULL;
 
-#ifdef USE_STACKCHECK
-	if (tstate->recursion_depth%10 == 0 && PyOS_CheckStack()) {
-		PyErr_SetString(PyExc_MemoryError, "Stack overflow");
-		return NULL;
-	}
-#endif
-
 	/* push frame */
-	if (++tstate->recursion_depth > recursion_limit) {
-		--tstate->recursion_depth;
-		PyErr_SetString(PyExc_RuntimeError,
-				"maximum recursion depth exceeded");
-		tstate->frame = f->f_back;
+	if (Py_EnterRecursiveCall(""))
 		return NULL;
-	}
 
 	tstate->frame = f;
 
@@ -710,9 +729,7 @@ eval_frame(PyFrameObject *f)
 			if (call_trace(tstate->c_tracefunc, tstate->c_traceobj,
 				       f, PyTrace_CALL, Py_None)) {
 				/* Trace function raised an error */
-				--tstate->recursion_depth;
-				tstate->frame = f->f_back;
-				return NULL;
+				goto exit_eval_frame;
 			}
 		}
 		if (tstate->c_profilefunc != NULL) {
@@ -722,9 +739,7 @@ eval_frame(PyFrameObject *f)
 				       tstate->c_profileobj,
 				       f, PyTrace_CALL, Py_None)) {
 				/* Profile function raised an error */
-				--tstate->recursion_depth;
-				tstate->frame = f->f_back;
-				return NULL;
+				goto exit_eval_frame;
 			}
 		}
 	}
@@ -2428,7 +2443,8 @@ eval_frame(PyFrameObject *f)
 	reset_exc_info(tstate);
 
 	/* pop frame */
-	--tstate->recursion_depth;
+    exit_eval_frame:
+	Py_LeaveRecursiveCall();
 	tstate->frame = f->f_back;
 
 	return retval;