GH-127705: Add debug mode for `_PyStackRef`s inspired by HPy debug mode (GH-128121)

1 files changed, 15 insertions, 8 deletions

diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index ee5c55a..bed16b6 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -208,7 +208,7 @@
                  */
                 assert(Py_REFCNT(left_o) >= 2);
                 PyStackRef_CLOSE(left);
-                PyObject *temp = PyStackRef_AsPyObjectBorrow(*target_local);
+                PyObject *temp = PyStackRef_AsPyObjectSteal(*target_local);
                 PyUnicode_Append(&temp, right_o);
                 *target_local = PyStackRef_FromPyObjectSteal(temp);
                 PyStackRef_CLOSE_SPECIALIZED(right, _PyUnicode_ExactDealloc);
@@ -1675,16 +1675,16 @@
                 callargs_st = tuple;
                 func_st = func;
                 PyObject *func = PyStackRef_AsPyObjectBorrow(func_st);
-                PyObject *callargs = PyStackRef_AsPyObjectBorrow(callargs_st);
-                PyObject *kwargs = PyStackRef_AsPyObjectBorrow(kwargs_st);
                 // DICT_MERGE is called before this opcode if there are kwargs.
                 // It converts all dict subtypes in kwargs into regular dicts.
-                assert(kwargs == NULL || PyDict_CheckExact(kwargs));
-                assert(PyTuple_CheckExact(callargs));
                 EVAL_CALL_STAT_INC_IF_FUNCTION(EVAL_CALL_FUNCTION_EX, func);
                 PyObject *result_o;
                 assert(!_PyErr_Occurred(tstate));
                 if (opcode == INSTRUMENTED_CALL_FUNCTION_EX) {
+                    PyObject *callargs = PyStackRef_AsPyObjectBorrow(callargs_st);
+                    PyObject *kwargs = PyStackRef_AsPyObjectBorrow(kwargs_st);
+                    assert(kwargs == NULL || PyDict_CheckExact(kwargs));
+                    assert(PyTuple_CheckExact(callargs));
                     PyObject *arg = PyTuple_GET_SIZE(callargs) > 0 ?
                     PyTuple_GET_ITEM(callargs, 0) : &_PyInstrumentation_MISSING;
                     stack_pointer[-1 - (oparg & 1)] = callargs_st;
@@ -1724,19 +1724,22 @@
                     if (Py_TYPE(func) == &PyFunction_Type &&
                         tstate->interp->eval_frame == NULL &&
                         ((PyFunctionObject *)func)->vectorcall == _PyFunction_Vectorcall) {
+                        PyObject *callargs = PyStackRef_AsPyObjectSteal(callargs_st);
                         assert(PyTuple_CheckExact(callargs));
+                        PyObject *kwargs = PyStackRef_IsNull(kwargs_st) ? NULL : PyStackRef_AsPyObjectSteal(kwargs_st);
+                        assert(kwargs == NULL || PyDict_CheckExact(kwargs));
                         Py_ssize_t nargs = PyTuple_GET_SIZE(callargs);
                         int code_flags = ((PyCodeObject *)PyFunction_GET_CODE(func))->co_flags;
                         PyObject *locals = code_flags & CO_OPTIMIZED ? NULL : Py_NewRef(PyFunction_GET_GLOBALS(func));
-                        stack_pointer[-1 - (oparg & 1)] = callargs_st;
-                        if (oparg & 1) stack_pointer[-(oparg & 1)] = kwargs_st;
+                        stack_pointer += -2 - (oparg & 1);
+                        assert(WITHIN_STACK_BOUNDS());
                         _PyFrame_SetStackPointer(frame, stack_pointer);
                         _PyInterpreterFrame *new_frame = _PyEvalFramePushAndInit_Ex(
                             tstate, func_st, locals,
                             nargs, callargs, kwargs, frame);
                         stack_pointer = _PyFrame_GetStackPointer(frame);
                         // Need to sync the stack since we exit with DISPATCH_INLINED.
-                        stack_pointer += -3 - (oparg & 1);
+                        stack_pointer += -1;
                         assert(WITHIN_STACK_BOUNDS());
                         if (new_frame == NULL) {
                             goto error;
@@ -1745,6 +1748,10 @@
                         frame->return_offset = 1;
                         DISPATCH_INLINED(new_frame);
                     }
+                    PyObject *callargs = PyStackRef_AsPyObjectBorrow(callargs_st);
+                    assert(PyTuple_CheckExact(callargs));
+                    PyObject *kwargs = PyStackRef_AsPyObjectBorrow(kwargs_st);
+                    assert(kwargs == NULL || PyDict_CheckExact(kwargs));
                     stack_pointer[-1 - (oparg & 1)] = callargs_st;
                     if (oparg & 1) stack_pointer[-(oparg & 1)] = kwargs_st;
                     _PyFrame_SetStackPointer(frame, stack_pointer);