Fix tier2 optimizer

Author: colesbury

Include/internal/pycore_frame.h

@@ -84,6 +84,12 @@ static inline PyCodeObject *_PyFrame_GetCode(_PyInterpreterFrame *f) {
     return (PyCodeObject *)executable;
 }
 
+static inline PyFunctionObject *_PyFrame_GetFunction(_PyInterpreterFrame *f) {
+    PyObject *func = PyStackRef_AsPyObjectBorrow(f->f_funcobj);
+    assert(PyFunction_Check(func));
+    return (PyFunctionObject *)func;
+}
+
 static inline _PyStackRef *_PyFrame_Stackbase(_PyInterpreterFrame *f) {
     return (f->localsplus + _PyFrame_GetCode(f)->co_nlocalsplus);
 }

Modules/_testinternalcapi.c

@@ -682,7 +682,7 @@ static PyObject *
 record_eval(PyThreadState *tstate, struct _PyInterpreterFrame *f, int exc)
 {
     if (PyStackRef_FunctionCheck(f->f_funcobj)) {
-        PyFunctionObject *func = (PyFunctionObject *)PyStackRef_AsPyObjectBorrow(f->f_funcobj);
+        PyFunctionObject *func = _PyFrame_GetFunction(f);
         PyObject *module = _get_current_module();
         assert(module != NULL);
         module_state *state = get_module_state(module);

Objects/frameobject.c

@@ -1868,7 +1868,7 @@ frame_init_get_vars(_PyInterpreterFrame *frame)
     }
 
     /* Free vars have not been initialized -- Do that */
-    PyFunctionObject *func = (PyFunctionObject *)PyStackRef_AsPyObjectBorrow(frame->f_funcobj);
+    PyFunctionObject *func = _PyFrame_GetFunction(frame);
     PyObject *closure = func->func_closure;
     int offset = PyUnstable_Code_GetFirstFree(co);
     for (int i = 0; i < co->co_nfreevars; ++i) {

Python/optimizer.c

@@ -533,7 +533,7 @@ translate_bytecode_to_trace(
 {
     bool first = true;
     PyCodeObject *code = _PyFrame_GetCode(frame);
-    PyFunctionObject *func = (PyFunctionObject *)frame->f_funcobj;
+    PyFunctionObject *func = _PyFrame_GetFunction(frame);
     assert(PyFunction_Check(func));
     PyCodeObject *initial_code = code;
     _Py_BloomFilter_Add(dependencies, initial_code);

Python/optimizer_analysis.c

@@ -145,7 +145,7 @@ remove_globals(_PyInterpreterFrame *frame, _PyUOpInstruction *buffer,
         return 1;
     }
     PyObject *globals = frame->f_globals;
-    PyFunctionObject *function = (PyFunctionObject *)frame->f_funcobj;
+    PyFunctionObject *function = _PyFrame_GetFunction(frame);
     assert(PyFunction_Check(function));
     assert(function->func_builtins == builtins);
     assert(function->func_globals == globals);