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Merged
Fidget-Spinner merged 18 commits into from
Sep 13, 2024
Merged

gh-121459: Deferred LOAD_GLOBAL #123128

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803e9f7
deferred globals
Fidget-Spinner Jul 4, 2024
b213b6f
fix merge from upstream
Fidget-Spinner Aug 18, 2024
11d2fb6
use cases generator to generate stack offsets
Fidget-Spinner Aug 18, 2024
ea8d855
fix bug
Fidget-Spinner Aug 18, 2024
af0c032
add type annotations
Fidget-Spinner Aug 18, 2024
1a431de
Update Objects/dictobject.c
Fidget-Spinner Aug 19, 2024
48bebe9
Update Objects/dictobject.c
Fidget-Spinner Aug 19, 2024
6e948b4
Update Objects/dictobject.c
Fidget-Spinner Aug 19, 2024
e23567a
Address review
Fidget-Spinner Aug 19, 2024
dbbebf9
Merge branch 'deferred_globals_final' of github.com:Fidget-Spinner/cp…
Fidget-Spinner Aug 19, 2024
dbdee10
partially address review
Fidget-Spinner Aug 22, 2024
6d176c0
simplify
Fidget-Spinner Aug 22, 2024
4ff9f17
fix some stuff
Fidget-Spinner Aug 22, 2024
c644ebf
specialize for str and split str, move out NULL checks
Fidget-Spinner Aug 28, 2024
64f932a
remove allow_unbalanced_parens
Fidget-Spinner Aug 28, 2024
bfd4400
Add a & for STACK_ENTRY
Fidget-Spinner Aug 28, 2024
0c1ee7e
Address review
Fidget-Spinner Sep 8, 2024
ad33dd1
Change to use array instead of STACK_ENTRY
Fidget-Spinner Sep 12, 2024
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Address review 
Co-Authored-By: Sam Gross <655866+colesbury@users.noreply.github.com>
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@Fidget-Spinner @colesbury
Fidget-Spinner and colesbury committed Sep 8, 2024
commit 0c1ee7e42c71f689dd97392f1abefe44e4db8c0d
127 changes: 27 additions & 100 deletions Objects/dictobject.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1499,113 +1499,39 @@ _Py_dict_lookup_threadsafe(PyDictObject *mp, PyObject *key, Py_hash_t hash, PyOb
Py_ssize_t
_Py_dict_lookup_threadsafe_stackref(PyDictObject *mp, PyObject *key, Py_hash_t hash, _PyStackRef *value_addr)
{
PyDictKeysObject *dk;
DictKeysKind kind;
Py_ssize_t ix;

ensure_shared_on_read(mp);

dk = _Py_atomic_load_ptr(&mp->ma_keys);
kind = dk->dk_kind;

if (kind != DICT_KEYS_GENERAL) {
if (PyUnicode_CheckExact(key)) {
ix = unicodekeys_lookup_unicode_threadsafe(dk, key, hash);
}
else {
ix = unicodekeys_lookup_generic_threadsafe(mp, dk, key, hash);
}
if (ix == DKIX_KEY_CHANGED) {
goto read_failed;
PyDictKeysObject *dk = _Py_atomic_load_ptr(&mp->ma_keys);
if (dk->dk_kind == DICT_KEYS_UNICODE && PyUnicode_CheckExact(key)) {
Py_ssize_t ix = unicodekeys_lookup_unicode_threadsafe(dk, key, hash);
if (ix == DKIX_EMPTY) {
*value_addr = PyStackRef_NULL;
return ix;
}

if (ix >= 0) {
if (kind == DICT_KEYS_SPLIT) {
PyDictValues *values = _Py_atomic_load_ptr(&mp->ma_values);
if (values == NULL) {
goto read_failed;
}

uint8_t capacity = _Py_atomic_load_uint8_relaxed(&values->capacity);
if (ix >= (Py_ssize_t)capacity) {
goto read_failed;
}

PyObject **addr_of_value = &values->values[ix];
PyObject *value = _Py_atomic_load_ptr(addr_of_value);
if (value == NULL) {
*value_addr = PyStackRef_NULL;
}
else if (_Py_IsImmortal(value) ||
_PyObject_HasDeferredRefcount(value)) {
*value_addr = PyStackRef_FromPyObjectNew(value);
}
else {
PyObject *res = _Py_TryXGetRef(addr_of_value);
if (res == NULL) {
*value_addr = PyStackRef_NULL;
}
else {
*value_addr = PyStackRef_FromPyObjectSteal(res);
}
}
if (PyStackRef_IsNull(*value_addr)) {
goto read_failed;
}
if (values != _Py_atomic_load_ptr(&mp->ma_values)) {
goto read_failed;
}
else if (ix >= 0) {
PyObject **addr_of_value = &DK_UNICODE_ENTRIES(dk)[ix].me_value;
PyObject *value = _Py_atomic_load_ptr(addr_of_value);
if (value == NULL) {
*value_addr = PyStackRef_NULL;
return DKIX_EMPTY;
}
else {
PyObject **addr_of_value = &DK_UNICODE_ENTRIES(dk)[ix].me_value;
PyObject *value = _Py_atomic_load_ptr(addr_of_value);
if (value == NULL) {
*value_addr = PyStackRef_NULL;
}
else if (_Py_IsImmortal(value) ||
_PyObject_HasDeferredRefcount(value)) {
*value_addr = PyStackRef_FromPyObjectNew(value);
}
else {
PyObject *res = _Py_TryXGetRef(addr_of_value);
if (res == NULL) {
*value_addr = PyStackRef_NULL;
}
else {
*value_addr = PyStackRef_FromPyObjectSteal(res);
}
}
if (PyStackRef_IsNull(*value_addr)) {
goto read_failed;
}
if (dk != _Py_atomic_load_ptr(&mp->ma_keys)) {
goto read_failed;
}
if (_Py_IsImmortal(value) || _PyObject_HasDeferredRefcount(value)) {
*value_addr = (_PyStackRef){ .bits = (uintptr_t)value | Py_TAG_DEFERRED };
return ix;
}
if (_Py_TryIncrefCompare(addr_of_value, value)) {
*value_addr = PyStackRef_FromPyObjectSteal(value);
return ix;
}
}
else {
*value_addr = PyStackRef_NULL;
}
}

PyObject *obj;
Py_ssize_t ix = _Py_dict_lookup_threadsafe(mp, key, hash, &obj);
if (ix >= 0 && obj != NULL) {
*value_addr = PyStackRef_FromPyObjectSteal(obj);
}
else {
PyObject *value;
ix = _Py_dict_lookup_threadsafe(mp, key, hash, &value);
assert (ix >= 0 || value == NULL);
*value_addr = PyStackRef_FromPyObjectSteal(value);
*value_addr = PyStackRef_NULL;
}

return ix;

PyObject *value;
read_failed:
// In addition to the normal races of the dict being modified the _Py_TryXGetRef
// can all fail if they don't yet have a shared ref count. That can happen here
// or in the *_lookup_* helper. In that case we need to take the lock to avoid
// mutation and do a normal incref which will make them shared.
Py_BEGIN_CRITICAL_SECTION(mp);
ix = _Py_dict_lookup(mp, key, hash, &value);
*value_addr = value == NULL ? PyStackRef_NULL : PyStackRef_FromPyObjectNew(value);
Py_END_CRITICAL_SECTION();
return ix;
}

Expand Down Expand Up @@ -2549,6 +2475,7 @@ _PyDict_LoadGlobalStackRef(PyDictObject *globals, PyDictObject *builtins, PyObje
hash = _PyObject_HashFast(key);
if (hash == -1) {
*res = PyStackRef_NULL;
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return;
}

/* namespace 1: globals */
Expand Down