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gh-120906: Support arbitrary hashable keys in FrameLocalsProxy (GH-122309)

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Co-authored-by: Alyssa Coghlan <ncoghlan@gmail.com>
This commit is contained in:
Petr Viktorin
2024-07-31 00:11:00 +02:00
committed by GitHub
parent 1cac0908fb
commit 5912487938
3 changed files with 208 additions and 60 deletions
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140
Objects/frameobject.c
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@@ -53,22 +53,27 @@ static int
framelocalsproxy_getkeyindex(PyFrameObject *frame, PyObject* key, bool read)
{
/*
* Returns the fast locals index of the key
* Returns -2 (!) if an error occurred; exception will be set.
* Returns the fast locals index of the key on success:
* - if read == true, returns the index if the value is not NULL
* - if read == false, returns the index if the value is not hidden
* Otherwise returns -1.
*/
assert(PyUnicode_CheckExact(key));
PyCodeObject *co = _PyFrame_GetCode(frame->f_frame);
int found_key = false;
// Ensure that the key is hashable.
Py_hash_t key_hash = PyObject_Hash(key);
if (key_hash == -1) {
return -2;
}
bool found = 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;
@@ -78,23 +83,35 @@ framelocalsproxy_getkeyindex(PyFrameObject *frame, PyObject* key, bool read)
return i;
}
}
found = true;
}
}
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;
}
if (found) {
// This is an attempt to read an unset local variable or
// write to a variable that is hidden from regular write operations
return -1;
}
// 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);
Py_hash_t name_hash = PyObject_Hash(name);
assert(name_hash != -1); // keys are exact unicode
if (name_hash != key_hash) {
continue;
}
int same = PyObject_RichCompareBool(name, key, Py_EQ);
if (same < 0) {
return -2;
}
if (same) {
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;
}
}
}
@@ -109,13 +126,14 @@ 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);
}
int i = framelocalsproxy_getkeyindex(frame, key, true);
if (i == -2) {
return NULL;
}
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
@@ -145,37 +163,38 @@ framelocalsproxy_setitem(PyObject *self, PyObject *key, PyObject *value)
return -1;
}
if (PyUnicode_CheckExact(key)) {
int i = framelocalsproxy_getkeyindex(frame, key, false);
if (i >= 0) {
_Py_Executors_InvalidateDependency(PyInterpreterState_Get(), co, 1);
int i = framelocalsproxy_getkeyindex(frame, key, false);
if (i == -2) {
return -1;
}
if (i >= 0) {
_Py_Executors_InvalidateDependency(PyInterpreterState_Get(), co, 1);
_PyLocals_Kind kind = _PyLocals_GetKind(co->co_localspluskinds, i);
_PyStackRef 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.bits != 0 && PyCell_Check(PyStackRef_AsPyObjectBorrow(oldvalue)));
cell = PyStackRef_AsPyObjectBorrow(oldvalue);
} else if (kind & CO_FAST_CELL && oldvalue.bits != 0) {
PyObject *as_obj = PyStackRef_AsPyObjectBorrow(oldvalue);
if (PyCell_Check(as_obj)) {
cell = as_obj;
}
_PyLocals_Kind kind = _PyLocals_GetKind(co->co_localspluskinds, i);
_PyStackRef 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.bits != 0 && PyCell_Check(PyStackRef_AsPyObjectBorrow(oldvalue)));
cell = PyStackRef_AsPyObjectBorrow(oldvalue);
} else if (kind & CO_FAST_CELL && oldvalue.bits != 0) {
PyObject *as_obj = PyStackRef_AsPyObjectBorrow(oldvalue);
if (PyCell_Check(as_obj)) {
cell = as_obj;
}
if (cell != NULL) {
PyObject *oldvalue_o = PyCell_GET(cell);
if (value != oldvalue_o) {
PyCell_SET(cell, Py_XNewRef(value));
Py_XDECREF(oldvalue_o);
}
} else if (value != PyStackRef_AsPyObjectBorrow(oldvalue)) {
PyStackRef_XCLOSE(fast[i]);
fast[i] = PyStackRef_FromPyObjectNew(value);
}
return 0;
}
if (cell != NULL) {
PyObject *oldvalue_o = PyCell_GET(cell);
if (value != oldvalue_o) {
PyCell_SET(cell, Py_XNewRef(value));
Py_XDECREF(oldvalue_o);
}
} else if (value != PyStackRef_AsPyObjectBorrow(oldvalue)) {
PyStackRef_XCLOSE(fast[i]);
fast[i] = PyStackRef_FromPyObjectNew(value);
}
return 0;
}
// Okay not in the fast locals, try extra locals
@@ -545,11 +564,12 @@ 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;
}
int i = framelocalsproxy_getkeyindex(frame, key, true);
if (i == -2) {
return -1;
}
if (i >= 0) {
return 1;
}
PyObject *extra = ((PyFrameObject*)frame)->f_extra_locals;