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cpython/Objects/frameobject.c
Alyssa Coghlan 3859e09e3d
gh-74929: PEP 667 C API documentation (gh-119379) 
* Add docs for new APIs
* Add soft-deprecation notices
* Add What's New porting entries
* Update comments referencing `PyFrame_LocalsToFast()` to mention the proxy instead
* Other related cleanups found when looking for refs to the deprecated APIs
2024-06-01 13:59:35 +10:00

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/* Frame object implementation */
#include "Python.h"
#include "pycore_ceval.h" // _PyEval_BuiltinsFromGlobals()
#include "pycore_code.h" // CO_FAST_LOCAL, etc.
#include "pycore_function.h" // _PyFunction_FromConstructor()
#include "pycore_moduleobject.h" // _PyModule_GetDict()
#include "pycore_object.h" // _PyObject_GC_UNTRACK()
#include "pycore_opcode_metadata.h" // _PyOpcode_Deopt, _PyOpcode_Caches
#include "frameobject.h" // PyFrameObject
#include "pycore_frame.h"
#include "opcode.h" // EXTENDED_ARG
#define OFF(x) offsetof(PyFrameObject, x)
// Returns borrowed reference or NULL
static PyObject *
framelocalsproxy_getval(_PyInterpreterFrame *frame, PyCodeObject *co, int i)
{
PyObject **fast = _PyFrame_GetLocalsArray(frame);
_PyLocals_Kind kind = _PyLocals_GetKind(co->co_localspluskinds, i);
PyObject *value = fast[i];
PyObject *cell = NULL;
if (value == NULL) {
return NULL;
}
if (kind == CO_FAST_FREE || kind & CO_FAST_CELL) {
// The cell was set when the frame was created from
// the function's closure.
assert(PyCell_Check(value));
cell = value;
}
if (cell != NULL) {
value = PyCell_GET(cell);
}
if (value == NULL) {
return NULL;
}
return value;
}
static int
framelocalsproxy_getkeyindex(PyFrameObject *frame, PyObject* key, bool read)
{
/*
* Returns the fast locals index of the key
* - if read == true, returns the index if the value is not NULL
* - if read == false, returns the index if the value is not hidden
*/
assert(PyUnicode_CheckExact(key));
PyCodeObject *co = _PyFrame_GetCode(frame->f_frame);
int found_key = false;
// We do 2 loops here because it's highly possible the key is interned
// and we can do a pointer comparison.
for (int i = 0; i < co->co_nlocalsplus; i++) {
PyObject *name = PyTuple_GET_ITEM(co->co_localsplusnames, i);
if (name == key) {
found_key = true;
if (read) {
if (framelocalsproxy_getval(frame->f_frame, co, i) != NULL) {
return i;
}
} else {
if (!(_PyLocals_GetKind(co->co_localspluskinds, i) & CO_FAST_HIDDEN)) {
return i;
}
}
}
}
if (!found_key) {
// This is unlikely, but we need to make sure. This means the key
// is not interned.
for (int i = 0; i < co->co_nlocalsplus; i++) {
PyObject *name = PyTuple_GET_ITEM(co->co_localsplusnames, i);
if (_PyUnicode_EQ(name, key)) {
if (read) {
if (framelocalsproxy_getval(frame->f_frame, co, i) != NULL) {
return i;
}
} else {
if (!(_PyLocals_GetKind(co->co_localspluskinds, i) & CO_FAST_HIDDEN)) {
return i;
}
}
}
}
}
return -1;
}
static PyObject *
framelocalsproxy_getitem(PyObject *self, PyObject *key)
{
PyFrameObject* frame = ((PyFrameLocalsProxyObject*)self)->frame;
PyCodeObject* co = _PyFrame_GetCode(frame->f_frame);
if (PyUnicode_CheckExact(key)) {
int i = framelocalsproxy_getkeyindex(frame, key, true);
if (i >= 0) {
PyObject *value = framelocalsproxy_getval(frame->f_frame, co, i);
assert(value != NULL);
return Py_NewRef(value);
}
}
// Okay not in the fast locals, try extra locals
PyObject *extra = frame->f_extra_locals;
if (extra != NULL) {
PyObject *value = PyDict_GetItem(extra, key);
if (value != NULL) {
return Py_NewRef(value);
}
}
PyErr_Format(PyExc_KeyError, "local variable '%R' is not defined", key);
return NULL;
}
static int
framelocalsproxy_setitem(PyObject *self, PyObject *key, PyObject *value)
{
/* Merge locals into fast locals */
PyFrameObject* frame = ((PyFrameLocalsProxyObject*)self)->frame;
PyObject** fast = _PyFrame_GetLocalsArray(frame->f_frame);
PyCodeObject* co = _PyFrame_GetCode(frame->f_frame);
if (value == NULL) {
PyErr_SetString(PyExc_TypeError, "cannot remove variables from FrameLocalsProxy");
return -1;
}
if (PyUnicode_CheckExact(key)) {
int i = framelocalsproxy_getkeyindex(frame, key, false);
if (i >= 0) {
_Py_Executors_InvalidateDependency(PyInterpreterState_Get(), co, 1);
_PyLocals_Kind kind = _PyLocals_GetKind(co->co_localspluskinds, i);
PyObject *oldvalue = fast[i];
PyObject *cell = NULL;
if (kind == CO_FAST_FREE) {
// The cell was set when the frame was created from
// the function's closure.
assert(oldvalue != NULL && PyCell_Check(oldvalue));
cell = oldvalue;
} else if (kind & CO_FAST_CELL && oldvalue != NULL) {
if (PyCell_Check(oldvalue)) {
cell = oldvalue;
}
}
if (cell != NULL) {
oldvalue = PyCell_GET(cell);
if (value != oldvalue) {
PyCell_SET(cell, Py_XNewRef(value));
Py_XDECREF(oldvalue);
}
} else if (value != oldvalue) {
Py_XSETREF(fast[i], Py_NewRef(value));
}
return 0;
}
}
// Okay not in the fast locals, try extra locals
PyObject *extra = frame->f_extra_locals;
if (extra == NULL) {
extra = PyDict_New();
if (extra == NULL) {
return -1;
}
frame->f_extra_locals = extra;
}
assert(PyDict_Check(extra));
return PyDict_SetItem(extra, key, value);
}
static int
framelocalsproxy_merge(PyObject* self, PyObject* other)
{
if (!PyDict_Check(other) && !PyFrameLocalsProxy_Check(other)) {
return -1;
}
PyObject *keys = PyMapping_Keys(other);
if (keys == NULL) {
return -1;
}
PyObject *iter = PyObject_GetIter(keys);
Py_DECREF(keys);
if (iter == NULL) {
return -1;
}
PyObject *key = NULL;
PyObject *value = NULL;
while ((key = PyIter_Next(iter)) != NULL) {
value = PyObject_GetItem(other, key);
if (value == NULL) {
Py_DECREF(key);
Py_DECREF(iter);
return -1;
}
if (framelocalsproxy_setitem(self, key, value) < 0) {
Py_DECREF(key);
Py_DECREF(value);
Py_DECREF(iter);
return -1;
}
Py_DECREF(key);
Py_DECREF(value);
}
Py_DECREF(iter);
return 0;
}
static PyObject *
framelocalsproxy_keys(PyObject *self, void *Py_UNUSED(ignored))
{
PyFrameObject *frame = ((PyFrameLocalsProxyObject*)self)->frame;
PyCodeObject *co = _PyFrame_GetCode(frame->f_frame);
PyObject *names = PyList_New(0);
if (names == NULL) {
return NULL;
}
for (int i = 0; i < co->co_nlocalsplus; i++) {
PyObject *val = framelocalsproxy_getval(frame->f_frame, co, i);
if (val) {
PyObject *name = PyTuple_GET_ITEM(co->co_localsplusnames, i);
if (PyList_Append(names, name) < 0) {
Py_DECREF(names);
return NULL;
}
}
}
// Iterate through the extra locals
if (frame->f_extra_locals) {
assert(PyDict_Check(frame->f_extra_locals));
Py_ssize_t i = 0;
PyObject *key = NULL;
PyObject *value = NULL;
while (PyDict_Next(frame->f_extra_locals, &i, &key, &value)) {
if (PyList_Append(names, key) < 0) {
Py_DECREF(names);
return NULL;
}
}
}
return names;
}
static void
framelocalsproxy_dealloc(PyObject *self)
{
PyObject_GC_UnTrack(self);
Py_CLEAR(((PyFrameLocalsProxyObject*)self)->frame);
Py_TYPE(self)->tp_free(self);
}
static PyObject *
framelocalsproxy_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
PyFrameLocalsProxyObject *self = (PyFrameLocalsProxyObject *)type->tp_alloc(type, 0);
if (self == NULL) {
return NULL;
}
PyFrameObject *frame = (PyFrameObject*)PyTuple_GET_ITEM(args, 0);
assert(PyFrame_Check(frame));
((PyFrameLocalsProxyObject*)self)->frame = (PyFrameObject*)Py_NewRef(frame);
return (PyObject *)self;
}
static int
framelocalsproxy_tp_clear(PyObject *self)
{
Py_CLEAR(((PyFrameLocalsProxyObject*)self)->frame);
return 0;
}
static int
framelocalsproxy_visit(PyObject *self, visitproc visit, void *arg)
{
Py_VISIT(((PyFrameLocalsProxyObject*)self)->frame);
return 0;
}
static PyObject *
framelocalsproxy_iter(PyObject *self)
{
PyObject* keys = framelocalsproxy_keys(self, NULL);
if (keys == NULL) {
return NULL;
}
PyObject* iter = PyObject_GetIter(keys);
Py_XDECREF(keys);
return iter;
}
static PyObject *
framelocalsproxy_richcompare(PyObject *self, PyObject *other, int op)
{
if (PyFrameLocalsProxy_Check(other)) {
bool result = ((PyFrameLocalsProxyObject*)self)->frame == ((PyFrameLocalsProxyObject*)other)->frame;
if (op == Py_EQ) {
return PyBool_FromLong(result);
} else if (op == Py_NE) {
return PyBool_FromLong(!result);
}
} else if (PyDict_Check(other)) {
PyObject *dct = PyDict_New();
if (dct == NULL) {
return NULL;
}
if (PyDict_Update(dct, self) < 0) {
Py_DECREF(dct);
return NULL;
}
PyObject *result = PyObject_RichCompare(dct, other, op);
Py_DECREF(dct);
return result;
}
Py_RETURN_NOTIMPLEMENTED;
}
static PyObject *
framelocalsproxy_repr(PyObject *self)
{
int i = Py_ReprEnter(self);
if (i != 0) {
return i > 0 ? PyUnicode_FromString("{...}") : NULL;
}
PyObject *dct = PyDict_New();
if (dct == NULL) {
Py_ReprLeave(self);
return NULL;
}
if (PyDict_Update(dct, self) < 0) {
Py_DECREF(dct);
Py_ReprLeave(self);
return NULL;
}
PyObject *repr = PyObject_Repr(dct);
Py_DECREF(dct);
Py_ReprLeave(self);
return repr;
}
static PyObject*
framelocalsproxy_or(PyObject *self, PyObject *other)
{
if (!PyDict_Check(other) && !PyFrameLocalsProxy_Check(other)) {
Py_RETURN_NOTIMPLEMENTED;
}
PyObject *result = PyDict_New();
if (result == NULL) {
return NULL;
}
if (PyDict_Update(result, self) < 0) {
Py_DECREF(result);
return NULL;
}
if (PyDict_Update(result, other) < 0) {
Py_DECREF(result);
return NULL;
}
return result;
}
static PyObject*
framelocalsproxy_inplace_or(PyObject *self, PyObject *other)
{
if (!PyDict_Check(other) && !PyFrameLocalsProxy_Check(other)) {
Py_RETURN_NOTIMPLEMENTED;
}
if (framelocalsproxy_merge(self, other) < 0) {
Py_RETURN_NOTIMPLEMENTED;
}
return Py_NewRef(self);
}
static PyObject*
framelocalsproxy_values(PyObject *self, void *Py_UNUSED(ignored))
{
PyFrameObject *frame = ((PyFrameLocalsProxyObject*)self)->frame;
PyCodeObject *co = _PyFrame_GetCode(frame->f_frame);
PyObject *values = PyList_New(0);
if (values == NULL) {
return NULL;
}
for (int i = 0; i < co->co_nlocalsplus; i++) {
PyObject *value = framelocalsproxy_getval(frame->f_frame, co, i);
if (value) {
if (PyList_Append(values, value) < 0) {
Py_DECREF(values);
return NULL;
}
}
}
// Iterate through the extra locals
if (frame->f_extra_locals) {
Py_ssize_t j = 0;
PyObject *key = NULL;
PyObject *value = NULL;
while (PyDict_Next(frame->f_extra_locals, &j, &key, &value)) {
if (PyList_Append(values, value) < 0) {
Py_DECREF(values);
return NULL;
}
}
}
return values;
}
static PyObject *
framelocalsproxy_items(PyObject *self, void *Py_UNUSED(ignored))
{
PyFrameObject *frame = ((PyFrameLocalsProxyObject*)self)->frame;
PyCodeObject *co = _PyFrame_GetCode(frame->f_frame);
PyObject *items = PyList_New(0);
if (items == NULL) {
return NULL;
}
for (int i = 0; i < co->co_nlocalsplus; i++) {
PyObject *name = PyTuple_GET_ITEM(co->co_localsplusnames, i);
PyObject *value = framelocalsproxy_getval(frame->f_frame, co, i);
if (value) {
PyObject *pair = PyTuple_Pack(2, name, value);
if (pair == NULL) {
Py_DECREF(items);
return NULL;
}
if (PyList_Append(items, pair) < 0) {
Py_DECREF(items);
Py_DECREF(pair);
return NULL;
}
Py_DECREF(pair);
}
}
// Iterate through the extra locals
if (frame->f_extra_locals) {
Py_ssize_t j = 0;
PyObject *key = NULL;
PyObject *value = NULL;
while (PyDict_Next(frame->f_extra_locals, &j, &key, &value)) {
PyObject *pair = PyTuple_Pack(2, key, value);
if (pair == NULL) {
Py_DECREF(items);
return NULL;
}
if (PyList_Append(items, pair) < 0) {
Py_DECREF(items);
Py_DECREF(pair);
return NULL;
}
Py_DECREF(pair);
}
}
return items;
}
static Py_ssize_t
framelocalsproxy_length(PyObject *self)
{
PyFrameObject *frame = ((PyFrameLocalsProxyObject*)self)->frame;
PyCodeObject *co = _PyFrame_GetCode(frame->f_frame);
Py_ssize_t size = 0;
if (frame->f_extra_locals != NULL) {
assert(PyDict_Check(frame->f_extra_locals));
size += PyDict_Size(frame->f_extra_locals);
}
for (int i = 0; i < co->co_nlocalsplus; i++) {
if (framelocalsproxy_getval(frame->f_frame, co, i) != NULL) {
size++;
}
}
return size;
}
static int
framelocalsproxy_contains(PyObject *self, PyObject *key)
{
PyFrameObject *frame = ((PyFrameLocalsProxyObject*)self)->frame;
if (PyUnicode_CheckExact(key)) {
int i = framelocalsproxy_getkeyindex(frame, key, true);
if (i >= 0) {
return 1;
}
}
PyObject *extra = ((PyFrameObject*)frame)->f_extra_locals;
if (extra != NULL) {
return PyDict_Contains(extra, key);
}
return 0;
}
static PyObject* framelocalsproxy___contains__(PyObject *self, PyObject *key)
{
int result = framelocalsproxy_contains(self, key);
if (result < 0) {
return NULL;
}
return PyBool_FromLong(result);
}
static PyObject*
framelocalsproxy_update(PyObject *self, PyObject *other)
{
if (framelocalsproxy_merge(self, other) < 0) {
PyErr_SetString(PyExc_TypeError, "update() argument must be dict or another FrameLocalsProxy");
return NULL;
}
Py_RETURN_NONE;
}
static PyObject*
framelocalsproxy_get(PyObject* self, PyObject *const *args, Py_ssize_t nargs)
{
if (nargs < 1 || nargs > 2) {
PyErr_SetString(PyExc_TypeError, "get expected 1 or 2 arguments");
return NULL;
}
PyObject *key = args[0];
PyObject *default_value = Py_None;
if (nargs == 2) {
default_value = args[1];
}
PyObject *result = framelocalsproxy_getitem(self, key);
if (result == NULL) {
if (PyErr_ExceptionMatches(PyExc_KeyError)) {
PyErr_Clear();
return Py_XNewRef(default_value);
}
return NULL;
}
return result;
}
static PyObject*
framelocalsproxy_setdefault(PyObject* self, PyObject *const *args, Py_ssize_t nargs)
{
if (nargs < 1 || nargs > 2) {
PyErr_SetString(PyExc_TypeError, "setdefault expected 1 or 2 arguments");
return NULL;
}
PyObject *key = args[0];
PyObject *default_value = Py_None;
if (nargs == 2) {
default_value = args[1];
}
PyObject *result = framelocalsproxy_getitem(self, key);
if (result == NULL) {
if (PyErr_ExceptionMatches(PyExc_KeyError)) {
PyErr_Clear();
if (framelocalsproxy_setitem(self, key, default_value) < 0) {
return NULL;
}
return Py_XNewRef(default_value);
}
return NULL;
}
return result;
}
static PyObject*
framelocalsproxy_copy(PyObject *self, PyObject *Py_UNUSED(ignored))
{
PyObject* result = PyDict_New();
if (result == NULL) {
return NULL;
}
if (PyDict_Update(result, self) < 0) {
Py_DECREF(result);
return NULL;
}
return result;
}
static PyObject*
framelocalsproxy_reversed(PyObject *self, void *Py_UNUSED(ignored))
{
PyObject *result = framelocalsproxy_keys(self, NULL);
if (result == NULL) {
return NULL;
}
if (PyList_Reverse(result) < 0) {
Py_DECREF(result);
return NULL;
}
return result;
}
static PyNumberMethods framelocalsproxy_as_number = {
.nb_or = framelocalsproxy_or,
.nb_inplace_or = framelocalsproxy_inplace_or,
};
static PySequenceMethods framelocalsproxy_as_sequence = {
.sq_contains = framelocalsproxy_contains,
};
static PyMappingMethods framelocalsproxy_as_mapping = {
framelocalsproxy_length, // mp_length
framelocalsproxy_getitem, // mp_subscript
framelocalsproxy_setitem, // mp_ass_subscript
};
static PyMethodDef framelocalsproxy_methods[] = {
{"__contains__", framelocalsproxy___contains__, METH_O | METH_COEXIST,
NULL},
{"__getitem__", framelocalsproxy_getitem, METH_O | METH_COEXIST,
NULL},
{"update", framelocalsproxy_update, METH_O,
NULL},
{"__reversed__", _PyCFunction_CAST(framelocalsproxy_reversed), METH_NOARGS,
NULL},
{"copy", _PyCFunction_CAST(framelocalsproxy_copy), METH_NOARGS,
NULL},
{"keys", _PyCFunction_CAST(framelocalsproxy_keys), METH_NOARGS,
NULL},
{"values", _PyCFunction_CAST(framelocalsproxy_values), METH_NOARGS,
NULL},
{"items", _PyCFunction_CAST(framelocalsproxy_items), METH_NOARGS,
NULL},
{"get", _PyCFunction_CAST(framelocalsproxy_get), METH_FASTCALL,
NULL},
{"setdefault", _PyCFunction_CAST(framelocalsproxy_setdefault), METH_FASTCALL,
NULL},
{NULL, NULL} /* sentinel */
};
PyTypeObject PyFrameLocalsProxy_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
.tp_name = "FrameLocalsProxy",
.tp_basicsize = sizeof(PyFrameLocalsProxyObject),
.tp_dealloc = (destructor)framelocalsproxy_dealloc,
.tp_repr = &framelocalsproxy_repr,
.tp_as_number = &framelocalsproxy_as_number,
.tp_as_sequence = &framelocalsproxy_as_sequence,
.tp_as_mapping = &framelocalsproxy_as_mapping,
.tp_getattro = PyObject_GenericGetAttr,
.tp_setattro = PyObject_GenericSetAttr,
.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
.tp_traverse = framelocalsproxy_visit,
.tp_clear = framelocalsproxy_tp_clear,
.tp_richcompare = framelocalsproxy_richcompare,
.tp_iter = framelocalsproxy_iter,
.tp_methods = framelocalsproxy_methods,
.tp_alloc = PyType_GenericAlloc,
.tp_new = framelocalsproxy_new,
.tp_free = PyObject_GC_Del,
};
PyObject *
_PyFrameLocalsProxy_New(PyFrameObject *frame)
{
PyObject* args = PyTuple_Pack(1, frame);
if (args == NULL) {
return NULL;
}
PyObject* proxy = (PyObject*)framelocalsproxy_new(&PyFrameLocalsProxy_Type, args, NULL);
Py_DECREF(args);
return proxy;
}
static PyMemberDef frame_memberlist[] = {
{"f_trace_lines", Py_T_BOOL, OFF(f_trace_lines), 0},
{NULL} /* Sentinel */
};
static PyObject *
frame_getlocals(PyFrameObject *f, void *closure)
{
if (f == NULL) {
PyErr_BadInternalCall();
return NULL;
}
assert(!_PyFrame_IsIncomplete(f->f_frame));
PyCodeObject *co = _PyFrame_GetCode(f->f_frame);
if (!(co->co_flags & CO_OPTIMIZED) && !_PyFrame_HasHiddenLocals(f->f_frame)) {
if (f->f_frame->f_locals == NULL) {
// We found cases when f_locals is NULL for non-optimized code.
// We fill the f_locals with an empty dict to avoid crash until
// we find the root cause.
f->f_frame->f_locals = PyDict_New();
if (f->f_frame->f_locals == NULL) {
return NULL;
}
}
return Py_NewRef(f->f_frame->f_locals);
}
return _PyFrameLocalsProxy_New(f);
}
int
PyFrame_GetLineNumber(PyFrameObject *f)
{
assert(f != NULL);
if (f->f_lineno == -1) {
// We should calculate it once. If we can't get the line number,
// set f->f_lineno to 0.
f->f_lineno = PyUnstable_InterpreterFrame_GetLine(f->f_frame);
if (f->f_lineno < 0) {
f->f_lineno = 0;
return -1;
}
}
if (f->f_lineno > 0) {
return f->f_lineno;
}
return PyUnstable_InterpreterFrame_GetLine(f->f_frame);
}
static PyObject *
frame_getlineno(PyFrameObject *f, void *closure)
{
int lineno = PyFrame_GetLineNumber(f);
if (lineno < 0) {
Py_RETURN_NONE;
}
else {
return PyLong_FromLong(lineno);
}
}
static PyObject *
frame_getlasti(PyFrameObject *f, void *closure)
{
int lasti = _PyInterpreterFrame_LASTI(f->f_frame);
if (lasti < 0) {
return PyLong_FromLong(-1);
}
return PyLong_FromLong(lasti * sizeof(_Py_CODEUNIT));
}
static PyObject *
frame_getglobals(PyFrameObject *f, void *closure)
{
PyObject *globals = f->f_frame->f_globals;
if (globals == NULL) {
globals = Py_None;
}
return Py_NewRef(globals);
}
static PyObject *
frame_getbuiltins(PyFrameObject *f, void *closure)
{
PyObject *builtins = f->f_frame->f_builtins;
if (builtins == NULL) {
builtins = Py_None;
}
return Py_NewRef(builtins);
}
static PyObject *
frame_getcode(PyFrameObject *f, void *closure)
{
if (PySys_Audit("object.__getattr__", "Os", f, "f_code") < 0) {
return NULL;
}
return (PyObject *)PyFrame_GetCode(f);
}
static PyObject *
frame_getback(PyFrameObject *f, void *closure)
{
PyObject *res = (PyObject *)PyFrame_GetBack(f);
if (res == NULL) {
Py_RETURN_NONE;
}
return res;
}
static PyObject *
frame_gettrace_opcodes(PyFrameObject *f, void *closure)
{
PyObject *result = f->f_trace_opcodes ? Py_True : Py_False;
return Py_NewRef(result);
}
static int
frame_settrace_opcodes(PyFrameObject *f, PyObject* value, void *Py_UNUSED(ignored))
{
if (!PyBool_Check(value)) {
PyErr_SetString(PyExc_TypeError,
"attribute value type must be bool");
return -1;
}
if (value == Py_True) {
f->f_trace_opcodes = 1;
if (f->f_trace) {
return _PyEval_SetOpcodeTrace(f, true);
}
}
else {
f->f_trace_opcodes = 0;
return _PyEval_SetOpcodeTrace(f, false);
}
return 0;
}
/* Model the evaluation stack, to determine which jumps
* are safe and how many values needs to be popped.
* The stack is modelled by a 64 integer, treating any
* stack that can't fit into 64 bits as "overflowed".
*/
typedef enum kind {
Iterator = 1,
Except = 2,
Object = 3,
Null = 4,
Lasti = 5,
} Kind;
static int
compatible_kind(Kind from, Kind to) {
if (to == 0) {
return 0;
}
if (to == Object) {
return from != Null;
}
if (to == Null) {
return 1;
}
return from == to;
}
#define BITS_PER_BLOCK 3
#define UNINITIALIZED -2
#define OVERFLOWED -1
#define MAX_STACK_ENTRIES (63/BITS_PER_BLOCK)
#define WILL_OVERFLOW (1ULL<<((MAX_STACK_ENTRIES-1)*BITS_PER_BLOCK))
#define EMPTY_STACK 0
static inline int64_t
push_value(int64_t stack, Kind kind)
{
if (((uint64_t)stack) >= WILL_OVERFLOW) {
return OVERFLOWED;
}
else {
return (stack << BITS_PER_BLOCK) | kind;
}
}
static inline int64_t
pop_value(int64_t stack)
{
return Py_ARITHMETIC_RIGHT_SHIFT(int64_t, stack, BITS_PER_BLOCK);
}
#define MASK ((1<<BITS_PER_BLOCK)-1)
static inline Kind
top_of_stack(int64_t stack)
{
return stack & MASK;
}
static inline Kind
peek(int64_t stack, int n)
{
assert(n >= 1);
return (stack>>(BITS_PER_BLOCK*(n-1))) & MASK;
}
static Kind
stack_swap(int64_t stack, int n)
{
assert(n >= 1);
Kind to_swap = peek(stack, n);
Kind top = top_of_stack(stack);
int shift = BITS_PER_BLOCK*(n-1);
int64_t replaced_low = (stack & ~(MASK << shift)) | (top << shift);
int64_t replaced_top = (replaced_low & ~MASK) | to_swap;
return replaced_top;
}
static int64_t
pop_to_level(int64_t stack, int level) {
if (level == 0) {
return EMPTY_STACK;
}
int64_t max_item = (1<<BITS_PER_BLOCK) - 1;
int64_t level_max_stack = max_item << ((level-1) * BITS_PER_BLOCK);
while (stack > level_max_stack) {
stack = pop_value(stack);
}
return stack;
}
#if 0
/* These functions are useful for debugging the stack marking code */
static char
tos_char(int64_t stack) {
switch(top_of_stack(stack)) {
case Iterator:
return 'I';
case Except:
return 'E';
case Object:
return 'O';
case Lasti:
return 'L';
case Null:
return 'N';
}
return '?';
}
static void
print_stack(int64_t stack) {
if (stack < 0) {
if (stack == UNINITIALIZED) {
printf("---");
}
else if (stack == OVERFLOWED) {
printf("OVERFLOWED");
}
else {
printf("??");
}
return;
}
while (stack) {
printf("%c", tos_char(stack));
stack = pop_value(stack);
}
}
static void
print_stacks(int64_t *stacks, int n) {
for (int i = 0; i < n; i++) {
printf("%d: ", i);
print_stack(stacks[i]);
printf("\n");
}
}
#endif
static int64_t *
mark_stacks(PyCodeObject *code_obj, int len)
{
PyObject *co_code = _PyCode_GetCode(code_obj);
if (co_code == NULL) {
return NULL;
}
_Py_CODEUNIT *code = (_Py_CODEUNIT *)PyBytes_AS_STRING(co_code);
int64_t *stacks = PyMem_New(int64_t, len+1);
int i, j, opcode;
if (stacks == NULL) {
PyErr_NoMemory();
Py_DECREF(co_code);
return NULL;
}
for (int i = 1; i <= len; i++) {
stacks[i] = UNINITIALIZED;
}
stacks[0] = EMPTY_STACK;
int todo = 1;
while (todo) {
todo = 0;
/* Scan instructions */
for (i = 0; i < len;) {
int64_t next_stack = stacks[i];
opcode = _Py_GetBaseOpcode(code_obj, i);
int oparg = 0;
while (opcode == EXTENDED_ARG) {
oparg = (oparg << 8) | code[i].op.arg;
i++;
opcode = _Py_GetBaseOpcode(code_obj, i);
stacks[i] = next_stack;
}
int next_i = i + _PyOpcode_Caches[opcode] + 1;
if (next_stack == UNINITIALIZED) {
i = next_i;
continue;
}
oparg = (oparg << 8) | code[i].op.arg;
switch (opcode) {
case POP_JUMP_IF_FALSE:
case POP_JUMP_IF_TRUE:
case POP_JUMP_IF_NONE:
case POP_JUMP_IF_NOT_NONE:
{
int64_t target_stack;
int j = next_i + oparg;
assert(j < len);
next_stack = pop_value(next_stack);
target_stack = next_stack;
assert(stacks[j] == UNINITIALIZED || stacks[j] == target_stack);
stacks[j] = target_stack;
stacks[next_i] = next_stack;
break;
}
case SEND:
j = oparg + i + INLINE_CACHE_ENTRIES_SEND + 1;
assert(j < len);
assert(stacks[j] == UNINITIALIZED || stacks[j] == next_stack);
stacks[j] = next_stack;
stacks[next_i] = next_stack;
break;
case JUMP_FORWARD:
j = oparg + i + 1;
assert(j < len);
assert(stacks[j] == UNINITIALIZED || stacks[j] == next_stack);
stacks[j] = next_stack;
break;
case JUMP_BACKWARD:
case JUMP_BACKWARD_NO_INTERRUPT:
j = next_i - oparg;
assert(j >= 0);
assert(j < len);
if (stacks[j] == UNINITIALIZED && j < i) {
todo = 1;
}
assert(stacks[j] == UNINITIALIZED || stacks[j] == next_stack);
stacks[j] = next_stack;
break;
case GET_ITER:
case GET_AITER:
next_stack = push_value(pop_value(next_stack), Iterator);
stacks[next_i] = next_stack;
break;
case FOR_ITER:
{
int64_t target_stack = push_value(next_stack, Object);
stacks[next_i] = target_stack;
j = oparg + 1 + INLINE_CACHE_ENTRIES_FOR_ITER + i;
assert(j < len);
assert(stacks[j] == UNINITIALIZED || stacks[j] == target_stack);
stacks[j] = target_stack;
break;
}
case END_ASYNC_FOR:
next_stack = pop_value(pop_value(next_stack));
stacks[next_i] = next_stack;
break;
case PUSH_EXC_INFO:
next_stack = push_value(next_stack, Except);
stacks[next_i] = next_stack;
break;
case POP_EXCEPT:
assert(top_of_stack(next_stack) == Except);
next_stack = pop_value(next_stack);
stacks[next_i] = next_stack;
break;
case RETURN_VALUE:
assert(pop_value(next_stack) == EMPTY_STACK);
assert(top_of_stack(next_stack) == Object);
break;
case RETURN_CONST:
break;
case RAISE_VARARGS:
break;
case RERAISE:
assert(top_of_stack(next_stack) == Except);
/* End of block */
break;
case PUSH_NULL:
next_stack = push_value(next_stack, Null);
stacks[next_i] = next_stack;
break;
case LOAD_GLOBAL:
{
int j = oparg;
next_stack = push_value(next_stack, Object);
if (j & 1) {
next_stack = push_value(next_stack, Null);
}
stacks[next_i] = next_stack;
break;
}
case LOAD_ATTR:
{
assert(top_of_stack(next_stack) == Object);
int j = oparg;
if (j & 1) {
next_stack = pop_value(next_stack);
next_stack = push_value(next_stack, Object);
next_stack = push_value(next_stack, Null);
}
stacks[next_i] = next_stack;
break;
}
case SWAP:
{
int n = oparg;
next_stack = stack_swap(next_stack, n);
stacks[next_i] = next_stack;
break;
}
case COPY:
{
int n = oparg;
next_stack = push_value(next_stack, peek(next_stack, n));
stacks[next_i] = next_stack;
break;
}
case CACHE:
case RESERVED:
{
assert(0);
}
default:
{
int delta = PyCompile_OpcodeStackEffect(opcode, oparg);
assert(delta != PY_INVALID_STACK_EFFECT);
while (delta < 0) {
next_stack = pop_value(next_stack);
delta++;
}
while (delta > 0) {
next_stack = push_value(next_stack, Object);
delta--;
}
stacks[next_i] = next_stack;
}
}
i = next_i;
}
/* Scan exception table */
unsigned char *start = (unsigned char *)PyBytes_AS_STRING(code_obj->co_exceptiontable);
unsigned char *end = start + PyBytes_GET_SIZE(code_obj->co_exceptiontable);
unsigned char *scan = start;
while (scan < end) {
int start_offset, size, handler;
scan = parse_varint(scan, &start_offset);
assert(start_offset >= 0 && start_offset < len);
scan = parse_varint(scan, &size);
assert(size >= 0 && start_offset+size <= len);
scan = parse_varint(scan, &handler);
assert(handler >= 0 && handler < len);
int depth_and_lasti;
scan = parse_varint(scan, &depth_and_lasti);
int level = depth_and_lasti >> 1;
int lasti = depth_and_lasti & 1;
if (stacks[start_offset] != UNINITIALIZED) {
if (stacks[handler] == UNINITIALIZED) {
todo = 1;
uint64_t target_stack = pop_to_level(stacks[start_offset], level);
if (lasti) {
target_stack = push_value(target_stack, Lasti);
}
target_stack = push_value(target_stack, Except);
stacks[handler] = target_stack;
}
}
}
}
Py_DECREF(co_code);
return stacks;
}
static int
compatible_stack(int64_t from_stack, int64_t to_stack)
{
if (from_stack < 0 || to_stack < 0) {
return 0;
}
while(from_stack > to_stack) {
from_stack = pop_value(from_stack);
}
while(from_stack) {
Kind from_top = top_of_stack(from_stack);
Kind to_top = top_of_stack(to_stack);
if (!compatible_kind(from_top, to_top)) {
return 0;
}
from_stack = pop_value(from_stack);
to_stack = pop_value(to_stack);
}
return to_stack == 0;
}
static const char *
explain_incompatible_stack(int64_t to_stack)
{
assert(to_stack != 0);
if (to_stack == OVERFLOWED) {
return "stack is too deep to analyze";
}
if (to_stack == UNINITIALIZED) {
return "can't jump into an exception handler, or code may be unreachable";
}
Kind target_kind = top_of_stack(to_stack);
switch(target_kind) {
case Except:
return "can't jump into an 'except' block as there's no exception";
case Lasti:
return "can't jump into a re-raising block as there's no location";
case Object:
case Null:
return "incompatible stacks";
case Iterator:
return "can't jump into the body of a for loop";
default:
Py_UNREACHABLE();
}
}
static int *
marklines(PyCodeObject *code, int len)
{
PyCodeAddressRange bounds;
_PyCode_InitAddressRange(code, &bounds);
assert (bounds.ar_end == 0);
int last_line = -1;
int *linestarts = PyMem_New(int, len);
if (linestarts == NULL) {
return NULL;
}
for (int i = 0; i < len; i++) {
linestarts[i] = -1;
}
while (_PyLineTable_NextAddressRange(&bounds)) {
assert(bounds.ar_start / (int)sizeof(_Py_CODEUNIT) < len);
if (bounds.ar_line != last_line && bounds.ar_line != -1) {
linestarts[bounds.ar_start / sizeof(_Py_CODEUNIT)] = bounds.ar_line;
last_line = bounds.ar_line;
}
}
return linestarts;
}
static int
first_line_not_before(int *lines, int len, int line)
{
int result = INT_MAX;
for (int i = 0; i < len; i++) {
if (lines[i] < result && lines[i] >= line) {
result = lines[i];
}
}
if (result == INT_MAX) {
return -1;
}
return result;
}
static bool frame_is_suspended(PyFrameObject *frame)
{
assert(!_PyFrame_IsIncomplete(frame->f_frame));
if (frame->f_frame->owner == FRAME_OWNED_BY_GENERATOR) {
PyGenObject *gen = _PyFrame_GetGenerator(frame->f_frame);
return FRAME_STATE_SUSPENDED(gen->gi_frame_state);
}
return false;
}
/* Setter for f_lineno - you can set f_lineno from within a trace function in
* order to jump to a given line of code, subject to some restrictions. Most
* lines are OK to jump to because they don't make any assumptions about the
* state of the stack (obvious because you could remove the line and the code
* would still work without any stack errors), but there are some constructs
* that limit jumping:
*
* o Any exception handlers.
* o 'for' and 'async for' loops can't be jumped into because the
* iterator needs to be on the stack.
* o Jumps cannot be made from within a trace function invoked with a
* 'return' or 'exception' event since the eval loop has been exited at
* that time.
*/
static int
frame_setlineno(PyFrameObject *f, PyObject* p_new_lineno, void *Py_UNUSED(ignored))
{
PyCodeObject *code = _PyFrame_GetCode(f->f_frame);
if (p_new_lineno == NULL) {
PyErr_SetString(PyExc_AttributeError, "cannot delete attribute");
return -1;
}
/* f_lineno must be an integer. */
if (!PyLong_CheckExact(p_new_lineno)) {
PyErr_SetString(PyExc_ValueError,
"lineno must be an integer");
return -1;
}
bool is_suspended = frame_is_suspended(f);
/*
* This code preserves the historical restrictions on
* setting the line number of a frame.
* Jumps are forbidden on a 'return' trace event (except after a yield).
* Jumps from 'call' trace events are also forbidden.
* In addition, jumps are forbidden when not tracing,
* as this is a debugging feature.
*/
int what_event = PyThreadState_GET()->what_event;
if (what_event < 0) {
PyErr_Format(PyExc_ValueError,
"f_lineno can only be set in a trace function");
return -1;
}
switch (what_event) {
case PY_MONITORING_EVENT_PY_RESUME:
case PY_MONITORING_EVENT_JUMP:
case PY_MONITORING_EVENT_BRANCH:
case PY_MONITORING_EVENT_LINE:
case PY_MONITORING_EVENT_PY_YIELD:
/* Setting f_lineno is allowed for the above events */
break;
case PY_MONITORING_EVENT_PY_START:
PyErr_Format(PyExc_ValueError,
"can't jump from the 'call' trace event of a new frame");
return -1;
case PY_MONITORING_EVENT_CALL:
case PY_MONITORING_EVENT_C_RETURN:
PyErr_SetString(PyExc_ValueError,
"can't jump during a call");
return -1;
case PY_MONITORING_EVENT_PY_RETURN:
case PY_MONITORING_EVENT_PY_UNWIND:
case PY_MONITORING_EVENT_PY_THROW:
case PY_MONITORING_EVENT_RAISE:
case PY_MONITORING_EVENT_C_RAISE:
case PY_MONITORING_EVENT_INSTRUCTION:
case PY_MONITORING_EVENT_EXCEPTION_HANDLED:
PyErr_Format(PyExc_ValueError,
"can only jump from a 'line' trace event");
return -1;
default:
PyErr_SetString(PyExc_SystemError,
"unexpected event type");
return -1;
}
int new_lineno;
/* Fail if the line falls outside the code block and
select first line with actual code. */
int overflow;
long l_new_lineno = PyLong_AsLongAndOverflow(p_new_lineno, &overflow);
if (overflow
#if SIZEOF_LONG > SIZEOF_INT
|| l_new_lineno > INT_MAX
|| l_new_lineno < INT_MIN
#endif
) {
PyErr_SetString(PyExc_ValueError,
"lineno out of range");
return -1;
}
new_lineno = (int)l_new_lineno;
if (new_lineno < code->co_firstlineno) {
PyErr_Format(PyExc_ValueError,
"line %d comes before the current code block",
new_lineno);
return -1;
}
/* PyCode_NewWithPosOnlyArgs limits co_code to be under INT_MAX so this
* should never overflow. */
int len = (int)Py_SIZE(code);
int *lines = marklines(code, len);
if (lines == NULL) {
return -1;
}
new_lineno = first_line_not_before(lines, len, new_lineno);
if (new_lineno < 0) {
PyErr_Format(PyExc_ValueError,
"line %d comes after the current code block",
(int)l_new_lineno);
PyMem_Free(lines);
return -1;
}
int64_t *stacks = mark_stacks(code, len);
if (stacks == NULL) {
PyMem_Free(lines);
return -1;
}
int64_t best_stack = OVERFLOWED;
int best_addr = -1;
int64_t start_stack = stacks[_PyInterpreterFrame_LASTI(f->f_frame)];
int err = -1;
const char *msg = "cannot find bytecode for specified line";
for (int i = 0; i < len; i++) {
if (lines[i] == new_lineno) {
int64_t target_stack = stacks[i];
if (compatible_stack(start_stack, target_stack)) {
err = 0;
if (target_stack > best_stack) {
best_stack = target_stack;
best_addr = i;
}
}
else if (err < 0) {
if (start_stack == OVERFLOWED) {
msg = "stack to deep to analyze";
}
else if (start_stack == UNINITIALIZED) {
msg = "can't jump from unreachable code";
}
else {
msg = explain_incompatible_stack(target_stack);
err = 1;
}
}
}
}
PyMem_Free(stacks);
PyMem_Free(lines);
if (err) {
PyErr_SetString(PyExc_ValueError, msg);
return -1;
}
// Populate any NULL locals that the compiler might have "proven" to exist
// in the new location. Rather than crashing or changing co_code, just bind
// None instead:
int unbound = 0;
for (int i = 0; i < code->co_nlocalsplus; i++) {
// Counting every unbound local is overly-cautious, but a full flow
// analysis (like we do in the compiler) is probably too expensive:
unbound += f->f_frame->localsplus[i] == NULL;
}
if (unbound) {
const char *e = "assigning None to %d unbound local%s";
const char *s = (unbound == 1) ? "" : "s";
if (PyErr_WarnFormat(PyExc_RuntimeWarning, 0, e, unbound, s)) {
return -1;
}
// Do this in a second pass to avoid writing a bunch of Nones when
// warnings are being treated as errors and the previous bit raises:
for (int i = 0; i < code->co_nlocalsplus; i++) {
if (f->f_frame->localsplus[i] == NULL) {
f->f_frame->localsplus[i] = Py_NewRef(Py_None);
unbound--;
}
}
assert(unbound == 0);
}
if (is_suspended) {
/* Account for value popped by yield */
start_stack = pop_value(start_stack);
}
while (start_stack > best_stack) {
if (top_of_stack(start_stack) == Except) {
/* Pop exception stack as well as the evaluation stack */
PyObject *exc = _PyFrame_StackPop(f->f_frame);
assert(PyExceptionInstance_Check(exc) || exc == Py_None);
PyThreadState *tstate = _PyThreadState_GET();
Py_XSETREF(tstate->exc_info->exc_value, exc == Py_None ? NULL : exc);
}
else {
PyObject *v = _PyFrame_StackPop(f->f_frame);
Py_XDECREF(v);
}
start_stack = pop_value(start_stack);
}
/* Finally set the new lasti and return OK. */
f->f_lineno = 0;
f->f_frame->instr_ptr = _PyCode_CODE(code) + best_addr;
return 0;
}
static PyObject *
frame_gettrace(PyFrameObject *f, void *closure)
{
PyObject* trace = f->f_trace;
if (trace == NULL)
trace = Py_None;
return Py_NewRef(trace);
}
static int
frame_settrace(PyFrameObject *f, PyObject* v, void *closure)
{
if (v == Py_None) {
v = NULL;
}
if (v != f->f_trace) {
Py_XSETREF(f->f_trace, Py_XNewRef(v));
if (v != NULL && f->f_trace_opcodes) {
return _PyEval_SetOpcodeTrace(f, true);
}
}
return 0;
}
static PyGetSetDef frame_getsetlist[] = {
{"f_back", (getter)frame_getback, NULL, NULL},
{"f_locals", (getter)frame_getlocals, NULL, NULL},
{"f_lineno", (getter)frame_getlineno,
(setter)frame_setlineno, NULL},
{"f_trace", (getter)frame_gettrace, (setter)frame_settrace, NULL},
{"f_lasti", (getter)frame_getlasti, NULL, NULL},
{"f_globals", (getter)frame_getglobals, NULL, NULL},
{"f_builtins", (getter)frame_getbuiltins, NULL, NULL},
{"f_code", (getter)frame_getcode, NULL, NULL},
{"f_trace_opcodes", (getter)frame_gettrace_opcodes, (setter)frame_settrace_opcodes, NULL},
{0}
};
static void
frame_dealloc(PyFrameObject *f)
{
/* It is the responsibility of the owning generator/coroutine
* to have cleared the generator pointer */
if (_PyObject_GC_IS_TRACKED(f)) {
_PyObject_GC_UNTRACK(f);
}
Py_TRASHCAN_BEGIN(f, frame_dealloc);
PyObject *co = NULL;
/* GH-106092: If f->f_frame was on the stack and we reached the maximum
* nesting depth for deallocations, the trashcan may have delayed this
* deallocation until after f->f_frame is freed. Avoid dereferencing
* f->f_frame unless we know it still points to valid memory. */
_PyInterpreterFrame *frame = (_PyInterpreterFrame *)f->_f_frame_data;
/* Kill all local variables including specials, if we own them */
if (f->f_frame == frame && frame->owner == FRAME_OWNED_BY_FRAME_OBJECT) {
/* Don't clear code object until the end */
co = frame->f_executable;
frame->f_executable = NULL;
Py_CLEAR(frame->f_funcobj);
Py_CLEAR(frame->f_locals);
PyObject **locals = _PyFrame_GetLocalsArray(frame);
for (int i = 0; i < frame->stacktop; i++) {
Py_CLEAR(locals[i]);
}
}
Py_CLEAR(f->f_back);
Py_CLEAR(f->f_trace);
Py_CLEAR(f->f_extra_locals);
PyObject_GC_Del(f);
Py_XDECREF(co);
Py_TRASHCAN_END;
}
static int
frame_traverse(PyFrameObject *f, visitproc visit, void *arg)
{
Py_VISIT(f->f_back);
Py_VISIT(f->f_trace);
Py_VISIT(f->f_extra_locals);
if (f->f_frame->owner != FRAME_OWNED_BY_FRAME_OBJECT) {
return 0;
}
assert(f->f_frame->frame_obj == NULL);
return _PyFrame_Traverse(f->f_frame, visit, arg);
}
static int
frame_tp_clear(PyFrameObject *f)
{
Py_CLEAR(f->f_trace);
Py_CLEAR(f->f_extra_locals);
/* locals and stack */
PyObject **locals = _PyFrame_GetLocalsArray(f->f_frame);
assert(f->f_frame->stacktop >= 0);
for (int i = 0; i < f->f_frame->stacktop; i++) {
Py_CLEAR(locals[i]);
}
f->f_frame->stacktop = 0;
Py_CLEAR(f->f_frame->f_locals);
return 0;
}
static PyObject *
frame_clear(PyFrameObject *f, PyObject *Py_UNUSED(ignored))
{
if (f->f_frame->owner == FRAME_OWNED_BY_GENERATOR) {
PyGenObject *gen = _PyFrame_GetGenerator(f->f_frame);
if (gen->gi_frame_state == FRAME_EXECUTING) {
goto running;
}
if (FRAME_STATE_SUSPENDED(gen->gi_frame_state)) {
goto suspended;
}
_PyGen_Finalize((PyObject *)gen);
}
else if (f->f_frame->owner == FRAME_OWNED_BY_THREAD) {
goto running;
}
else {
assert(f->f_frame->owner == FRAME_OWNED_BY_FRAME_OBJECT);
(void)frame_tp_clear(f);
}
Py_RETURN_NONE;
running:
PyErr_SetString(PyExc_RuntimeError,
"cannot clear an executing frame");
return NULL;
suspended:
PyErr_SetString(PyExc_RuntimeError,
"cannot clear a suspended frame");
return NULL;
}
PyDoc_STRVAR(clear__doc__,
"F.clear(): clear most references held by the frame");
static PyObject *
frame_sizeof(PyFrameObject *f, PyObject *Py_UNUSED(ignored))
{
Py_ssize_t res;
res = offsetof(PyFrameObject, _f_frame_data) + offsetof(_PyInterpreterFrame, localsplus);
PyCodeObject *code = _PyFrame_GetCode(f->f_frame);
res += _PyFrame_NumSlotsForCodeObject(code) * sizeof(PyObject *);
return PyLong_FromSsize_t(res);
}
PyDoc_STRVAR(sizeof__doc__,
"F.__sizeof__() -> size of F in memory, in bytes");
static PyObject *
frame_repr(PyFrameObject *f)
{
int lineno = PyFrame_GetLineNumber(f);
PyCodeObject *code = _PyFrame_GetCode(f->f_frame);
return PyUnicode_FromFormat(
"<frame at %p, file %R, line %d, code %S>",
f, code->co_filename, lineno, code->co_name);
}
static PyMethodDef frame_methods[] = {
{"clear", (PyCFunction)frame_clear, METH_NOARGS,
clear__doc__},
{"__sizeof__", (PyCFunction)frame_sizeof, METH_NOARGS,
sizeof__doc__},
{NULL, NULL} /* sentinel */
};
PyTypeObject PyFrame_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
"frame",
offsetof(PyFrameObject, _f_frame_data) +
offsetof(_PyInterpreterFrame, localsplus),
sizeof(PyObject *),
(destructor)frame_dealloc, /* tp_dealloc */
0, /* tp_vectorcall_offset */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_as_async */
(reprfunc)frame_repr, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
PyObject_GenericGetAttr, /* tp_getattro */
PyObject_GenericSetAttr, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,/* tp_flags */
0, /* tp_doc */
(traverseproc)frame_traverse, /* tp_traverse */
(inquiry)frame_tp_clear, /* tp_clear */
0, /* tp_richcompare */
0, /* tp_weaklistoffset */
0, /* tp_iter */
0, /* tp_iternext */
frame_methods, /* tp_methods */
frame_memberlist, /* tp_members */
frame_getsetlist, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
};
static void
init_frame(_PyInterpreterFrame *frame, PyFunctionObject *func, PyObject *locals)
{
PyCodeObject *code = (PyCodeObject *)func->func_code;
_PyFrame_Initialize(frame, (PyFunctionObject*)Py_NewRef(func),
Py_XNewRef(locals), code, 0);
frame->previous = NULL;
}
PyFrameObject*
_PyFrame_New_NoTrack(PyCodeObject *code)
{
CALL_STAT_INC(frame_objects_created);
int slots = code->co_nlocalsplus + code->co_stacksize;
PyFrameObject *f = PyObject_GC_NewVar(PyFrameObject, &PyFrame_Type, slots);
if (f == NULL) {
return NULL;
}
f->f_back = NULL;
f->f_trace = NULL;
f->f_trace_lines = 1;
f->f_trace_opcodes = 0;
f->f_lineno = 0;
f->f_extra_locals = NULL;
return f;
}
/* Legacy API */
PyFrameObject*
PyFrame_New(PyThreadState *tstate, PyCodeObject *code,
PyObject *globals, PyObject *locals)
{
PyObject *builtins = _PyEval_BuiltinsFromGlobals(tstate, globals); // borrowed ref
if (builtins == NULL) {
return NULL;
}
PyFrameConstructor desc = {
.fc_globals = globals,
.fc_builtins = builtins,
.fc_name = code->co_name,
.fc_qualname = code->co_name,
.fc_code = (PyObject *)code,
.fc_defaults = NULL,
.fc_kwdefaults = NULL,
.fc_closure = NULL
};
PyFunctionObject *func = _PyFunction_FromConstructor(&desc);
if (func == NULL) {
return NULL;
}
PyFrameObject *f = _PyFrame_New_NoTrack(code);
if (f == NULL) {
Py_DECREF(func);
return NULL;
}
init_frame((_PyInterpreterFrame *)f->_f_frame_data, func, locals);
f->f_frame = (_PyInterpreterFrame *)f->_f_frame_data;
f->f_frame->owner = FRAME_OWNED_BY_FRAME_OBJECT;
// This frame needs to be "complete", so pretend that the first RESUME ran:
f->f_frame->instr_ptr = _PyCode_CODE(code) + code->_co_firsttraceable + 1;
assert(!_PyFrame_IsIncomplete(f->f_frame));
Py_DECREF(func);
_PyObject_GC_TRACK(f);
return f;
}
// Initialize frame free variables if needed
static void
frame_init_get_vars(_PyInterpreterFrame *frame)
{
// COPY_FREE_VARS has no quickened forms, so no need to use _PyOpcode_Deopt
// here:
PyCodeObject *co = _PyFrame_GetCode(frame);
int lasti = _PyInterpreterFrame_LASTI(frame);
if (!(lasti < 0 && _PyCode_CODE(co)->op.code == COPY_FREE_VARS
&& PyFunction_Check(frame->f_funcobj)))
{
/* Free vars are initialized */
return;
}
/* Free vars have not been initialized -- Do that */
PyObject *closure = ((PyFunctionObject *)frame->f_funcobj)->func_closure;
int offset = PyUnstable_Code_GetFirstFree(co);
for (int i = 0; i < co->co_nfreevars; ++i) {
PyObject *o = PyTuple_GET_ITEM(closure, i);
frame->localsplus[offset + i] = Py_NewRef(o);
}
// COPY_FREE_VARS doesn't have inline CACHEs, either:
frame->instr_ptr = _PyCode_CODE(_PyFrame_GetCode(frame));
}
static int
frame_get_var(_PyInterpreterFrame *frame, PyCodeObject *co, int i,
PyObject **pvalue)
{
_PyLocals_Kind kind = _PyLocals_GetKind(co->co_localspluskinds, i);
/* If the namespace is unoptimized, then one of the
following cases applies:
1. It does not contain free variables, because it
uses import * or is a top-level namespace.
2. It is a class namespace.
We don't want to accidentally copy free variables
into the locals dict used by the class.
*/
if (kind & CO_FAST_FREE && !(co->co_flags & CO_OPTIMIZED)) {
return 0;
}
PyObject *value = frame->localsplus[i];
if (frame->stacktop) {
if (kind & CO_FAST_FREE) {
// The cell was set by COPY_FREE_VARS.
assert(value != NULL && PyCell_Check(value));
value = PyCell_GET(value);
}
else if (kind & CO_FAST_CELL) {
if (value != NULL) {
if (PyCell_Check(value)) {
assert(!_PyFrame_IsIncomplete(frame));
value = PyCell_GET(value);
}
// (likely) Otherwise it is an arg (kind & CO_FAST_LOCAL),
// with the initial value set when the frame was created...
// (unlikely) ...or it was set via the f_locals proxy.
}
}
}
else {
assert(value == NULL);
}
*pvalue = value;
return 1;
}
bool
_PyFrame_HasHiddenLocals(_PyInterpreterFrame *frame)
{
/*
* This function returns if there are hidden locals introduced by PEP 709,
* which are the isolated fast locals for inline comprehensions
*/
PyCodeObject* co = _PyFrame_GetCode(frame);
for (int i = 0; i < co->co_nlocalsplus; i++) {
_PyLocals_Kind kind = _PyLocals_GetKind(co->co_localspluskinds, i);
if (kind & CO_FAST_HIDDEN) {
PyObject* value = framelocalsproxy_getval(frame, co, i);
if (value != NULL) {
return true;
}
}
}
return false;
}
PyObject *
_PyFrame_GetLocals(_PyInterpreterFrame *frame)
{
// We should try to avoid creating the FrameObject if possible.
// So we check if the frame is a module or class level scope
PyCodeObject *co = _PyFrame_GetCode(frame);
if (!(co->co_flags & CO_OPTIMIZED) && !_PyFrame_HasHiddenLocals(frame)) {
if (frame->f_locals == NULL) {
// We found cases when f_locals is NULL for non-optimized code.
// We fill the f_locals with an empty dict to avoid crash until
// we find the root cause.
frame->f_locals = PyDict_New();
if (frame->f_locals == NULL) {
return NULL;
}
}
return Py_NewRef(frame->f_locals);
}
PyFrameObject* f = _PyFrame_GetFrameObject(frame);
return _PyFrameLocalsProxy_New(f);
}
PyObject *
PyFrame_GetVar(PyFrameObject *frame_obj, PyObject *name)
{
if (!PyUnicode_Check(name)) {
PyErr_Format(PyExc_TypeError, "name must be str, not %s",
Py_TYPE(name)->tp_name);
return NULL;
}
_PyInterpreterFrame *frame = frame_obj->f_frame;
frame_init_get_vars(frame);
PyCodeObject *co = _PyFrame_GetCode(frame);
for (int i = 0; i < co->co_nlocalsplus; i++) {
PyObject *var_name = PyTuple_GET_ITEM(co->co_localsplusnames, i);
if (!_PyUnicode_Equal(var_name, name)) {
continue;
}
PyObject *value; // borrowed reference
if (!frame_get_var(frame, co, i, &value)) {
break;
}
if (value == NULL) {
break;
}
return Py_NewRef(value);
}
PyErr_Format(PyExc_NameError, "variable %R does not exist", name);
return NULL;
}
PyObject *
PyFrame_GetVarString(PyFrameObject *frame, const char *name)
{
PyObject *name_obj = PyUnicode_FromString(name);
if (name_obj == NULL) {
return NULL;
}
PyObject *value = PyFrame_GetVar(frame, name_obj);
Py_DECREF(name_obj);
return value;
}
int
PyFrame_FastToLocalsWithError(PyFrameObject *f)
{
// Nothing to do here, as f_locals is now a write-through proxy in
// optimized frames. Soft-deprecated, since there's no maintenance hassle.
return 0;
}
void
PyFrame_FastToLocals(PyFrameObject *f)
{
// Nothing to do here, as f_locals is now a write-through proxy in
// optimized frames. Soft-deprecated, since there's no maintenance hassle.
return;
}
void
PyFrame_LocalsToFast(PyFrameObject *f, int clear)
{
// Nothing to do here, as f_locals is now a write-through proxy in
// optimized frames. Soft-deprecated, since there's no maintenance hassle.
return;
}
int
_PyFrame_IsEntryFrame(PyFrameObject *frame)
{
assert(frame != NULL);
_PyInterpreterFrame *f = frame->f_frame;
assert(!_PyFrame_IsIncomplete(f));
return f->previous && f->previous->owner == FRAME_OWNED_BY_CSTACK;
}
PyCodeObject *
PyFrame_GetCode(PyFrameObject *frame)
{
assert(frame != NULL);
assert(!_PyFrame_IsIncomplete(frame->f_frame));
PyCodeObject *code = _PyFrame_GetCode(frame->f_frame);
assert(code != NULL);
return (PyCodeObject*)Py_NewRef(code);
}
PyFrameObject*
PyFrame_GetBack(PyFrameObject *frame)
{
assert(frame != NULL);
assert(!_PyFrame_IsIncomplete(frame->f_frame));
PyFrameObject *back = frame->f_back;
if (back == NULL) {
_PyInterpreterFrame *prev = frame->f_frame->previous;
prev = _PyFrame_GetFirstComplete(prev);
if (prev) {
back = _PyFrame_GetFrameObject(prev);
}
}
return (PyFrameObject*)Py_XNewRef(back);
}
PyObject*
PyFrame_GetLocals(PyFrameObject *frame)
{
assert(!_PyFrame_IsIncomplete(frame->f_frame));
return frame_getlocals(frame, NULL);
}
PyObject*
PyFrame_GetGlobals(PyFrameObject *frame)
{
assert(!_PyFrame_IsIncomplete(frame->f_frame));
return frame_getglobals(frame, NULL);
}
PyObject*
PyFrame_GetBuiltins(PyFrameObject *frame)
{
assert(!_PyFrame_IsIncomplete(frame->f_frame));
return frame_getbuiltins(frame, NULL);
}
int
PyFrame_GetLasti(PyFrameObject *frame)
{
assert(!_PyFrame_IsIncomplete(frame->f_frame));
int lasti = _PyInterpreterFrame_LASTI(frame->f_frame);
if (lasti < 0) {
return -1;
}
return lasti * sizeof(_Py_CODEUNIT);
}
PyObject *
PyFrame_GetGenerator(PyFrameObject *frame)
{
assert(!_PyFrame_IsIncomplete(frame->f_frame));
if (frame->f_frame->owner != FRAME_OWNED_BY_GENERATOR) {
return NULL;
}
PyGenObject *gen = _PyFrame_GetGenerator(frame->f_frame);
return Py_NewRef(gen);
}
PyObject*
_PyEval_BuiltinsFromGlobals(PyThreadState *tstate, PyObject *globals)
{
PyObject *builtins = PyDict_GetItemWithError(globals, &_Py_ID(__builtins__));
if (builtins) {
if (PyModule_Check(builtins)) {
builtins = _PyModule_GetDict(builtins);
assert(builtins != NULL);
}
return builtins;
}
if (PyErr_Occurred()) {
return NULL;
}
return _PyEval_GetBuiltins(tstate);
}
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