1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
|
#include "Python.h"
#include "frameobject.h"
#include "pycore_code.h" // stats
#include "pycore_frame.h"
#include "pycore_object.h" // _PyObject_GC_UNTRACK()
#include "opcode.h"
int
_PyFrame_Traverse(_PyInterpreterFrame *frame, visitproc visit, void *arg)
{
Py_VISIT(frame->frame_obj);
Py_VISIT(frame->f_locals);
Py_VISIT(frame->f_func);
Py_VISIT(frame->f_code);
/* locals */
PyObject **locals = _PyFrame_GetLocalsArray(frame);
int i = 0;
/* locals and stack */
for (; i <frame->stacktop; i++) {
Py_VISIT(locals[i]);
}
return 0;
}
PyFrameObject *
_PyFrame_MakeAndSetFrameObject(_PyInterpreterFrame *frame)
{
assert(frame->frame_obj == NULL);
PyObject *error_type, *error_value, *error_traceback;
PyErr_Fetch(&error_type, &error_value, &error_traceback);
PyFrameObject *f = _PyFrame_New_NoTrack(frame->f_code);
if (f == NULL) {
Py_XDECREF(error_type);
Py_XDECREF(error_value);
Py_XDECREF(error_traceback);
return NULL;
}
PyErr_Restore(error_type, error_value, error_traceback);
if (frame->frame_obj) {
// GH-97002: How did we get into this horrible situation? Most likely,
// allocating f triggered a GC collection, which ran some code that
// *also* created the same frame... while we were in the middle of
// creating it! See test_sneaky_frame_object in test_frame.py for a
// concrete example.
//
// Regardless, just throw f away and use that frame instead, since it's
// already been exposed to user code. It's actually a bit tricky to do
// this, since we aren't backed by a real _PyInterpreterFrame anymore.
// Just pretend that we have an owned, cleared frame so frame_dealloc
// doesn't make the situation worse:
f->f_frame = (_PyInterpreterFrame *)f->_f_frame_data;
f->f_frame->owner = FRAME_CLEARED;
f->f_frame->frame_obj = f;
Py_DECREF(f);
return frame->frame_obj;
}
assert(frame->owner != FRAME_OWNED_BY_FRAME_OBJECT);
assert(frame->owner != FRAME_CLEARED);
f->f_frame = frame;
frame->frame_obj = f;
return f;
}
void
_PyFrame_Copy(_PyInterpreterFrame *src, _PyInterpreterFrame *dest)
{
assert(src->stacktop >= src->f_code->co_nlocalsplus);
Py_ssize_t size = ((char*)&src->localsplus[src->stacktop]) - (char *)src;
memcpy(dest, src, size);
// Don't leave a dangling pointer to the old frame when creating generators
// and coroutines:
dest->previous = NULL;
}
static void
take_ownership(PyFrameObject *f, _PyInterpreterFrame *frame)
{
assert(frame->owner != FRAME_OWNED_BY_FRAME_OBJECT);
assert(frame->owner != FRAME_CLEARED);
Py_ssize_t size = ((char*)&frame->localsplus[frame->stacktop]) - (char *)frame;
memcpy((_PyInterpreterFrame *)f->_f_frame_data, frame, size);
frame = (_PyInterpreterFrame *)f->_f_frame_data;
f->f_frame = frame;
frame->owner = FRAME_OWNED_BY_FRAME_OBJECT;
if (_PyFrame_IsIncomplete(frame)) {
// This may be a newly-created generator or coroutine frame. Since it's
// dead anyways, just pretend that the first RESUME ran:
PyCodeObject *code = frame->f_code;
frame->prev_instr = _PyCode_CODE(code) + code->_co_firsttraceable;
}
assert(!_PyFrame_IsIncomplete(frame));
assert(f->f_back == NULL);
_PyInterpreterFrame *prev = frame->previous;
while (prev && _PyFrame_IsIncomplete(prev)) {
prev = prev->previous;
}
if (prev) {
/* Link PyFrameObjects.f_back and remove link through _PyInterpreterFrame.previous */
PyFrameObject *back = _PyFrame_GetFrameObject(prev);
if (back == NULL) {
/* Memory error here. */
assert(PyErr_ExceptionMatches(PyExc_MemoryError));
/* Nothing we can do about it */
PyErr_Clear();
}
else {
f->f_back = (PyFrameObject *)Py_NewRef(back);
}
frame->previous = NULL;
}
if (!_PyObject_GC_IS_TRACKED((PyObject *)f)) {
_PyObject_GC_TRACK((PyObject *)f);
}
}
void
_PyFrame_Clear(_PyInterpreterFrame *frame)
{
/* It is the responsibility of the owning generator/coroutine
* to have cleared the enclosing generator, if any. */
assert(frame->owner != FRAME_OWNED_BY_GENERATOR ||
_PyFrame_GetGenerator(frame)->gi_frame_state == FRAME_CLEARED);
// GH-99729: Clearing this frame can expose the stack (via finalizers). It's
// crucial that this frame has been unlinked, and is no longer visible:
assert(_PyThreadState_GET()->cframe->current_frame != frame);
if (frame->frame_obj) {
PyFrameObject *f = frame->frame_obj;
frame->frame_obj = NULL;
if (Py_REFCNT(f) > 1) {
take_ownership(f, frame);
Py_DECREF(f);
return;
}
Py_DECREF(f);
}
assert(frame->stacktop >= 0);
for (int i = 0; i < frame->stacktop; i++) {
Py_XDECREF(frame->localsplus[i]);
}
Py_XDECREF(frame->frame_obj);
Py_XDECREF(frame->f_locals);
Py_DECREF(frame->f_func);
Py_DECREF(frame->f_code);
}
/* Consumes reference to func */
_PyInterpreterFrame *
_PyFrame_Push(PyThreadState *tstate, PyFunctionObject *func)
{
PyCodeObject *code = (PyCodeObject *)func->func_code;
size_t size = code->co_nlocalsplus + code->co_stacksize + FRAME_SPECIALS_SIZE;
CALL_STAT_INC(frames_pushed);
_PyInterpreterFrame *new_frame = _PyThreadState_BumpFramePointer(tstate, size);
if (new_frame == NULL) {
Py_DECREF(func);
return NULL;
}
_PyFrame_InitializeSpecials(new_frame, func, NULL, code->co_nlocalsplus);
return new_frame;
}
int
_PyInterpreterFrame_GetLine(_PyInterpreterFrame *frame)
{
int addr = _PyInterpreterFrame_LASTI(frame) * sizeof(_Py_CODEUNIT);
return PyCode_Addr2Line(frame->f_code, addr);
}
|
