gh-122313: Clean up deep recursion guarding code in the compiler (GH-122640)

Add ENTER_RECURSIVE and LEAVE_RECURSIVE macros in ast.c, ast_opt.c and
symtable.c. Remove VISIT_QUIT macro in symtable.c.

The current recursion depth counter only needs to be updated during
normal execution -- all functions should just return an error code
if an error occurs.

1 files changed, 22 insertions, 24 deletions

diff --git a/Python/ast.c b/Python/ast.c
index 1d1a48e..bf1ff5f 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -14,6 +14,20 @@ struct validator {
     int recursion_limit;            /* recursion limit */
 };
 
+#define ENTER_RECURSIVE(ST) \
+    do { \
+        if (++(ST)->recursion_depth > (ST)->recursion_limit) { \
+            PyErr_SetString(PyExc_RecursionError, \
+                "maximum recursion depth exceeded during compilation"); \
+            return 0; \
+        } \
+    } while(0)
+
+#define LEAVE_RECURSIVE(ST) \
+    do { \
+        --(ST)->recursion_depth; \
+    } while(0)
+
 static int validate_stmts(struct validator *, asdl_stmt_seq *);
 static int validate_exprs(struct validator *, asdl_expr_seq *, expr_context_ty, int);
 static int validate_patterns(struct validator *, asdl_pattern_seq *, int);
@@ -166,11 +180,7 @@ validate_constant(struct validator *state, PyObject *value)
         return 1;
 
     if (PyTuple_CheckExact(value) || PyFrozenSet_CheckExact(value)) {
-        if (++state->recursion_depth > state->recursion_limit) {
-            PyErr_SetString(PyExc_RecursionError,
-                            "maximum recursion depth exceeded during compilation");
-            return 0;
-        }
+        ENTER_RECURSIVE(state);
 
         PyObject *it = PyObject_GetIter(value);
         if (it == NULL)
@@ -195,7 +205,7 @@ validate_constant(struct validator *state, PyObject *value)
         }
 
         Py_DECREF(it);
-        --state->recursion_depth;
+        LEAVE_RECURSIVE(state);
         return 1;
     }
 
@@ -213,11 +223,7 @@ validate_expr(struct validator *state, expr_ty exp, expr_context_ty ctx)
     assert(!PyErr_Occurred());
     VALIDATE_POSITIONS(exp);
     int ret = -1;
-    if (++state->recursion_depth > state->recursion_limit) {
-        PyErr_SetString(PyExc_RecursionError,
-                        "maximum recursion depth exceeded during compilation");
-        return 0;
-    }
+    ENTER_RECURSIVE(state);
     int check_ctx = 1;
     expr_context_ty actual_ctx;
 
@@ -398,7 +404,7 @@ validate_expr(struct validator *state, expr_ty exp, expr_context_ty ctx)
         PyErr_SetString(PyExc_SystemError, "unexpected expression");
         ret = 0;
     }
-    state->recursion_depth--;
+    LEAVE_RECURSIVE(state);
     return ret;
 }
 
@@ -544,11 +550,7 @@ validate_pattern(struct validator *state, pattern_ty p, int star_ok)
     assert(!PyErr_Occurred());
     VALIDATE_POSITIONS(p);
     int ret = -1;
-    if (++state->recursion_depth > state->recursion_limit) {
-        PyErr_SetString(PyExc_RecursionError,
-                        "maximum recursion depth exceeded during compilation");
-        return 0;
-    }
+    ENTER_RECURSIVE(state);
     switch (p->kind) {
         case MatchValue_kind:
             ret = validate_pattern_match_value(state, p->v.MatchValue.value);
@@ -690,7 +692,7 @@ validate_pattern(struct validator *state, pattern_ty p, int star_ok)
         PyErr_SetString(PyExc_SystemError, "unexpected pattern");
         ret = 0;
     }
-    state->recursion_depth--;
+    LEAVE_RECURSIVE(state);
     return ret;
 }
 
@@ -725,11 +727,7 @@ validate_stmt(struct validator *state, stmt_ty stmt)
     assert(!PyErr_Occurred());
     VALIDATE_POSITIONS(stmt);
     int ret = -1;
-    if (++state->recursion_depth > state->recursion_limit) {
-        PyErr_SetString(PyExc_RecursionError,
-                        "maximum recursion depth exceeded during compilation");
-        return 0;
-    }
+    ENTER_RECURSIVE(state);
     switch (stmt->kind) {
     case FunctionDef_kind:
         ret = validate_body(state, stmt->v.FunctionDef.body, "FunctionDef") &&
@@ -946,7 +944,7 @@ validate_stmt(struct validator *state, stmt_ty stmt)
         PyErr_SetString(PyExc_SystemError, "unexpected statement");
         ret = 0;
     }
-    state->recursion_depth--;
+    LEAVE_RECURSIVE(state);
     return ret;
 }