Clean up how we access/walk the frame stack

python · brandtbucher · Jan 9, 2023 · Dec 29, 2022 · Dec 29, 2022 · Dec 29, 2022
commit 41c70e69f23515e72e48e2a7d54ad6fd9c1d9286
diff --git a/Modules/_tracemalloc.c b/Modules/_tracemalloc.c
@@ -347,14 +347,8 @@ traceback_get_frames(traceback_t *traceback)
         return;
     }
 
-    _PyInterpreterFrame *pyframe = tstate->cframe->current_frame;
-    for (;;) {
-        while (pyframe && _PyFrame_IsIncomplete(pyframe)) {
-            pyframe = pyframe->previous;
-        }
-        if (pyframe == NULL) {
-            break;
-        }
+    _PyInterpreterFrame *pyframe = _PyThreadState_GetFrame(tstate);
+    while (pyframe) {
         if (traceback->nframe < tracemalloc_config.max_nframe) {
             tracemalloc_get_frame(pyframe, &traceback->frames[traceback->nframe]);
             assert(traceback->frames[traceback->nframe].filename != NULL);
@@ -363,8 +357,7 @@ traceback_get_frames(traceback_t *traceback)
         if (traceback->total_nframe < UINT16_MAX) {
             traceback->total_nframe++;
         }
-
-        pyframe = pyframe->previous;
+        pyframe = _PyFrame_GetComplete(pyframe->previous);
     }
 }
 

diff --git a/Modules/signalmodule.c b/Modules/signalmodule.c
@@ -1803,10 +1803,7 @@ _PyErr_CheckSignalsTstate(PyThreadState *tstate)
      */
     _Py_atomic_store(&is_tripped, 0);
 
-    _PyInterpreterFrame *frame = tstate->cframe->current_frame;
-    while (frame && _PyFrame_IsIncomplete(frame)) {
-        frame = frame->previous;
-    }
+    _PyInterpreterFrame *frame = _PyThreadState_GetFrame(tstate);
     signal_state_t *state = &signal_global_state;
     for (int i = 1; i < Py_NSIG; i++) {
         if (!_Py_atomic_load_relaxed(&Handlers[i].tripped)) {

@@ -1408,9 +1408,7 @@ PyFrame_GetBack(PyFrameObject *frame)
     PyFrameObject *back = frame->f_back;
     if (back == NULL) {
         _PyInterpreterFrame *prev = frame->f_frame->previous;
-        while (prev && _PyFrame_IsIncomplete(prev)) {
-            prev = prev->previous;
-        }
+        prev = _PyFrame_GetComplete(prev);
         if (prev) {
             back = _PyFrame_GetFrameObject(prev);
         }

@@ -903,8 +903,11 @@ _Py_MakeCoro(PyFunctionObject *func)
     if (origin_depth == 0) {
         ((PyCoroObject *)coro)->cr_origin_or_finalizer = NULL;
     } else {
-        assert(_PyEval_GetFrame());
-        PyObject *cr_origin = compute_cr_origin(origin_depth, _PyEval_GetFrame()->previous);
+        _PyInterpreterFrame *frame = tstate->cframe->current_frame;
+        assert(frame);
+        assert(_PyFrame_IsIncomplete(frame));
+        frame = _PyFrame_GetComplete(frame->previous);
+        PyObject *cr_origin = compute_cr_origin(origin_depth, frame);
         ((PyCoroObject *)coro)->cr_origin_or_finalizer = cr_origin;
         if (!cr_origin) {
             Py_DECREF(coro);
@@ -1286,7 +1289,7 @@ compute_cr_origin(int origin_depth, _PyInterpreterFrame *current_frame)
     /* First count how many frames we have */
     int frame_count = 0;
     for (; frame && frame_count < origin_depth; ++frame_count) {
-        frame = frame->previous;
+        frame = _PyFrame_GetComplete(frame->previous);
     }
 
     /* Now collect them */
@@ -1305,7 +1308,7 @@ compute_cr_origin(int origin_depth, _PyInterpreterFrame *current_frame)
             return NULL;
         }
         PyTuple_SET_ITEM(cr_origin, i, frameinfo);
-        frame = frame->previous;
+        frame = _PyFrame_GetComplete(frame->previous);
     }
 
     return cr_origin;

@@ -9579,13 +9579,13 @@ super_init_impl(PyObject *self, PyTypeObject *type, PyObject *obj) {
         /* Call super(), without args -- fill in from __class__
            and first local variable on the stack. */
         PyThreadState *tstate = _PyThreadState_GET();
-        _PyInterpreterFrame *cframe = tstate->cframe->current_frame;
-        if (cframe == NULL) {
+        _PyInterpreterFrame *frame = _PyThreadState_GetFrame(tstate);
+        if (frame == NULL) {
             PyErr_SetString(PyExc_RuntimeError,
                             "super(): no current frame");
             return -1;
         }
-        int res = super_init_without_args(cframe, cframe->f_code, &type, &obj);
+        int res = super_init_without_args(frame, frame->f_code, &type, &obj);
 
         if (res < 0) {
             return -1;

@@ -2752,16 +2752,13 @@ _PyInterpreterFrame *
 _PyEval_GetFrame(void)
 {
     PyThreadState *tstate = _PyThreadState_GET();
-    return tstate->cframe->current_frame;
+    return _PyThreadState_GetFrame(tstate);
 }
 
 PyFrameObject *
 PyEval_GetFrame(void)
 {
     _PyInterpreterFrame *frame = _PyEval_GetFrame();
-    while (frame && _PyFrame_IsIncomplete(frame)) {
-        frame = frame->previous;
-    }
     if (frame == NULL) {
         return NULL;
     }
@@ -2775,7 +2772,7 @@ PyEval_GetFrame(void)
 PyObject *
 _PyEval_GetBuiltins(PyThreadState *tstate)
 {
-    _PyInterpreterFrame *frame = tstate->cframe->current_frame;
+    _PyInterpreterFrame *frame = _PyThreadState_GetFrame(tstate);
     if (frame != NULL) {
         return frame->f_builtins;
     }
@@ -2814,7 +2811,7 @@ PyObject *
 PyEval_GetLocals(void)
 {
     PyThreadState *tstate = _PyThreadState_GET();
-     _PyInterpreterFrame *current_frame = tstate->cframe->current_frame;
+     _PyInterpreterFrame *current_frame = _PyThreadState_GetFrame(tstate);
     if (current_frame == NULL) {
         _PyErr_SetString(tstate, PyExc_SystemError, "frame does not exist");
         return NULL;
@@ -2833,7 +2830,7 @@ PyObject *
 PyEval_GetGlobals(void)
 {
     PyThreadState *tstate = _PyThreadState_GET();
-    _PyInterpreterFrame *current_frame = tstate->cframe->current_frame;
+    _PyInterpreterFrame *current_frame = _PyThreadState_GetFrame(tstate);
     if (current_frame == NULL) {
         return NULL;
     }

diff --git a/Python/frame.c b/Python/frame.c
@@ -96,10 +96,7 @@ take_ownership(PyFrameObject *f, _PyInterpreterFrame *frame)
     }
     assert(!_PyFrame_IsIncomplete(frame));
     assert(f->f_back == NULL);
-    _PyInterpreterFrame *prev = frame->previous;
-    while (prev && _PyFrame_IsIncomplete(prev)) {
-        prev = prev->previous;
-    }
+    _PyInterpreterFrame *prev = _PyFrame_GetComplete(frame->previous);
     frame->previous = NULL;
     if (prev) {
         assert(prev->owner != FRAME_OWNED_BY_CSTACK);

@@ -1302,10 +1302,7 @@ PyFrameObject*
 PyThreadState_GetFrame(PyThreadState *tstate)
 {
     assert(tstate != NULL);
-    _PyInterpreterFrame *f = tstate->cframe->current_frame;
-    while (f && _PyFrame_IsIncomplete(f)) {
-        f = f->previous;
-    }
+    _PyInterpreterFrame *f = _PyThreadState_GetFrame(tstate);
     if (f == NULL) {
         return NULL;
     }
@@ -1431,9 +1428,7 @@ _PyThread_CurrentFrames(void)
         PyThreadState *t;
         for (t = i->threads.head; t != NULL; t = t->next) {
             _PyInterpreterFrame *frame = t->cframe->current_frame;
-            while (frame && _PyFrame_IsIncomplete(frame)) {
-                frame = frame->previous;
-            }
+            frame = _PyFrame_GetComplete(frame);
             if (frame == NULL) {
                 continue;
             }

@@ -1884,13 +1884,10 @@ sys__getframe_impl(PyObject *module, int depth)
 
     if (frame != NULL) {
         while (depth > 0) {
-            frame = frame->previous;
+            frame = _PyFrame_GetComplete(frame->previous);
             if (frame == NULL) {
                 break;
             }
-            if (_PyFrame_IsIncomplete(frame)) {
-                continue;
-            }
             --depth;
         }
     }