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gh-115999: Specialize STORE_ATTR in free-threaded builds. (gh-127838)

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* Add `_PyDictKeys_StringLookupSplit` which does locking on dict keys and
  use in place of `_PyDictKeys_StringLookup`.

* Change `_PyObject_TryGetInstanceAttribute` to use that function
  in the case of split keys.

* Add `unicodekeys_lookup_split` helper which allows code sharing
  between `_Py_dict_lookup` and `_PyDictKeys_StringLookupSplit`.

* Fix locking for `STORE_ATTR_INSTANCE_VALUE`.  Create
  `_GUARD_TYPE_VERSION_AND_LOCK` uop so that object stays locked and
  `tp_version_tag` cannot change.

* Pass `tp_version_tag` to `specialize_dict_access()`, ensuring
  the version we store on the cache is the correct one (in case of
  it changing during the specalize analysis).

* Split `analyze_descriptor` into `analyze_descriptor_load` and
  `analyze_descriptor_store` since those don't share much logic.
  Add `descriptor_is_class` helper function.

* In `specialize_dict_access`, double check `_PyObject_GetManagedDict()`
  in case we race and dict was materialized before the lock.

* Avoid borrowed references in `_Py_Specialize_StoreAttr()`.

* Use `specialize()` and `unspecialize()` helpers.

* Add unit tests to ensure specializing happens as expected in FT builds.

* Add unit tests to attempt to trigger data races (useful for running under TSAN).

* Add `has_split_table` function to `_testinternalcapi`.
This commit is contained in:
Neil Schemenauer 2024-12-19 10:21:17 -08:00 • committed by GitHub
parent d2f1d917e8
commit 1b15c89a17
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GPG key ID: B5690EEEBB952194
13 changed files with 716 additions and 297 deletions
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86
Python/generated_cases.c.h generated
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@ -5319,7 +5319,7 @@
uint32_t type_version = read_u32(&this_instr[4].cache);
PyTypeObject *tp = Py_TYPE(PyStackRef_AsPyObjectBorrow(owner));
assert(type_version != 0);
DEOPT_IF(tp->tp_version_tag != type_version, LOAD_ATTR);
DEOPT_IF(FT_ATOMIC_LOAD_UINT_RELAXED(tp->tp_version_tag) != type_version, LOAD_ATTR);
}
// _LOAD_ATTR_CLASS
{
@ -5388,7 +5388,7 @@
uint32_t type_version = read_u32(&this_instr[2].cache);
PyTypeObject *tp = Py_TYPE(PyStackRef_AsPyObjectBorrow(owner));
assert(type_version != 0);
DEOPT_IF(tp->tp_version_tag != type_version, LOAD_ATTR);
DEOPT_IF(FT_ATOMIC_LOAD_UINT_RELAXED(tp->tp_version_tag) != type_version, LOAD_ATTR);
}
// _CHECK_MANAGED_OBJECT_HAS_VALUES
{
@ -5433,7 +5433,7 @@
uint32_t type_version = read_u32(&this_instr[2].cache);
PyTypeObject *tp = Py_TYPE(PyStackRef_AsPyObjectBorrow(owner));
assert(type_version != 0);
DEOPT_IF(tp->tp_version_tag != type_version, LOAD_ATTR);
DEOPT_IF(FT_ATOMIC_LOAD_UINT_RELAXED(tp->tp_version_tag) != type_version, LOAD_ATTR);
}
// _CHECK_ATTR_METHOD_LAZY_DICT
{
@ -5476,7 +5476,7 @@
uint32_t type_version = read_u32(&this_instr[2].cache);
PyTypeObject *tp = Py_TYPE(PyStackRef_AsPyObjectBorrow(owner));
assert(type_version != 0);
DEOPT_IF(tp->tp_version_tag != type_version, LOAD_ATTR);
DEOPT_IF(FT_ATOMIC_LOAD_UINT_RELAXED(tp->tp_version_tag) != type_version, LOAD_ATTR);
}
/* Skip 2 cache entries */
// _LOAD_ATTR_METHOD_NO_DICT
@ -5512,7 +5512,7 @@
uint32_t type_version = read_u32(&this_instr[2].cache);
PyTypeObject *tp = Py_TYPE(PyStackRef_AsPyObjectBorrow(owner));
assert(type_version != 0);
DEOPT_IF(tp->tp_version_tag != type_version, LOAD_ATTR);
DEOPT_IF(FT_ATOMIC_LOAD_UINT_RELAXED(tp->tp_version_tag) != type_version, LOAD_ATTR);
}
// _GUARD_DORV_VALUES_INST_ATTR_FROM_DICT
{
@ -5611,7 +5611,7 @@
uint32_t type_version = read_u32(&this_instr[2].cache);
PyTypeObject *tp = Py_TYPE(PyStackRef_AsPyObjectBorrow(owner));
assert(type_version != 0);
DEOPT_IF(tp->tp_version_tag != type_version, LOAD_ATTR);
DEOPT_IF(FT_ATOMIC_LOAD_UINT_RELAXED(tp->tp_version_tag) != type_version, LOAD_ATTR);
}
/* Skip 2 cache entries */
// _LOAD_ATTR_NONDESCRIPTOR_NO_DICT
@ -5642,7 +5642,7 @@
uint32_t type_version = read_u32(&this_instr[2].cache);
PyTypeObject *tp = Py_TYPE(PyStackRef_AsPyObjectBorrow(owner));
assert(type_version != 0);
DEOPT_IF(tp->tp_version_tag != type_version, LOAD_ATTR);
DEOPT_IF(FT_ATOMIC_LOAD_UINT_RELAXED(tp->tp_version_tag) != type_version, LOAD_ATTR);
}
// _GUARD_DORV_VALUES_INST_ATTR_FROM_DICT
{
@ -5688,7 +5688,7 @@
uint32_t type_version = read_u32(&this_instr[2].cache);
PyTypeObject *tp = Py_TYPE(PyStackRef_AsPyObjectBorrow(owner));
assert(type_version != 0);
DEOPT_IF(tp->tp_version_tag != type_version, LOAD_ATTR);
DEOPT_IF(FT_ATOMIC_LOAD_UINT_RELAXED(tp->tp_version_tag) != type_version, LOAD_ATTR);
}
/* Skip 2 cache entries */
// _LOAD_ATTR_PROPERTY_FRAME
@ -5750,7 +5750,7 @@
uint32_t type_version = read_u32(&this_instr[2].cache);
PyTypeObject *tp = Py_TYPE(PyStackRef_AsPyObjectBorrow(owner));
assert(type_version != 0);
DEOPT_IF(tp->tp_version_tag != type_version, LOAD_ATTR);
DEOPT_IF(FT_ATOMIC_LOAD_UINT_RELAXED(tp->tp_version_tag) != type_version, LOAD_ATTR);
}
// _LOAD_ATTR_SLOT
{
@ -5787,7 +5787,7 @@
uint32_t type_version = read_u32(&this_instr[2].cache);
PyTypeObject *tp = Py_TYPE(PyStackRef_AsPyObjectBorrow(owner));
assert(type_version != 0);
DEOPT_IF(tp->tp_version_tag != type_version, LOAD_ATTR);
DEOPT_IF(FT_ATOMIC_LOAD_UINT_RELAXED(tp->tp_version_tag) != type_version, LOAD_ATTR);
}
// _CHECK_ATTR_WITH_HINT
{
@ -7314,7 +7314,7 @@
owner = stack_pointer[-1];
uint16_t counter = read_u16(&this_instr[1].cache);
(void)counter;
#if ENABLE_SPECIALIZATION
#if ENABLE_SPECIALIZATION_FT
if (ADAPTIVE_COUNTER_TRIGGERS(counter)) {
PyObject *name = GETITEM(FRAME_CO_NAMES, oparg);
next_instr = this_instr;
@ -7325,7 +7325,7 @@
}
OPCODE_DEFERRED_INC(STORE_ATTR);
ADVANCE_ADAPTIVE_COUNTER(this_instr[1].counter);
#endif /* ENABLE_SPECIALIZATION */
#endif /* ENABLE_SPECIALIZATION_FT */
}
/* Skip 3 cache entries */
// _STORE_ATTR
@ -7353,21 +7353,29 @@
_PyStackRef owner;
_PyStackRef value;
/* Skip 1 cache entry */
// _GUARD_TYPE_VERSION
// _GUARD_TYPE_VERSION_AND_LOCK
{
owner = stack_pointer[-1];
uint32_t type_version = read_u32(&this_instr[2].cache);
PyTypeObject *tp = Py_TYPE(PyStackRef_AsPyObjectBorrow(owner));
PyObject *owner_o = PyStackRef_AsPyObjectBorrow(owner);
assert(type_version != 0);
DEOPT_IF(tp->tp_version_tag != type_version, STORE_ATTR);
DEOPT_IF(!LOCK_OBJECT(owner_o), STORE_ATTR);
PyTypeObject *tp = Py_TYPE(owner_o);
if (FT_ATOMIC_LOAD_UINT_RELAXED(tp->tp_version_tag) != type_version) {
UNLOCK_OBJECT(owner_o);
DEOPT_IF(true, STORE_ATTR);
}
}
// _GUARD_DORV_NO_DICT
{
PyObject *owner_o = PyStackRef_AsPyObjectBorrow(owner);
assert(Py_TYPE(owner_o)->tp_dictoffset < 0);
assert(Py_TYPE(owner_o)->tp_flags & Py_TPFLAGS_INLINE_VALUES);
DEOPT_IF(_PyObject_GetManagedDict(owner_o), STORE_ATTR);
DEOPT_IF(_PyObject_InlineValues(owner_o)->valid == 0, STORE_ATTR);
if (_PyObject_GetManagedDict(owner_o) ||
!FT_ATOMIC_LOAD_UINT8(_PyObject_InlineValues(owner_o)->valid)) {
UNLOCK_OBJECT(owner_o);
DEOPT_IF(true, STORE_ATTR);
}
}
// _STORE_ATTR_INSTANCE_VALUE
{
@ -7378,15 +7386,14 @@
assert(_PyObject_GetManagedDict(owner_o) == NULL);
PyObject **value_ptr = (PyObject**)(((char *)owner_o) + offset);
PyObject *old_value = *value_ptr;
*value_ptr = PyStackRef_AsPyObjectSteal(value);
FT_ATOMIC_STORE_PTR_RELEASE(*value_ptr, PyStackRef_AsPyObjectSteal(value));
if (old_value == NULL) {
PyDictValues *values = _PyObject_InlineValues(owner_o);
Py_ssize_t index = value_ptr - values->values;
_PyDictValues_AddToInsertionOrder(values, index);
}
else {
Py_DECREF(old_value);
}
UNLOCK_OBJECT(owner_o);
Py_XDECREF(old_value);
PyStackRef_CLOSE(owner);
}
stack_pointer += -2;
@ -7408,17 +7415,19 @@
uint32_t type_version = read_u32(&this_instr[2].cache);
PyTypeObject *tp = Py_TYPE(PyStackRef_AsPyObjectBorrow(owner));
assert(type_version != 0);
DEOPT_IF(tp->tp_version_tag != type_version, STORE_ATTR);
DEOPT_IF(FT_ATOMIC_LOAD_UINT_RELAXED(tp->tp_version_tag) != type_version, STORE_ATTR);
}
// _STORE_ATTR_SLOT
{
value = stack_pointer[-2];
uint16_t index = read_u16(&this_instr[4].cache);
PyObject *owner_o = PyStackRef_AsPyObjectBorrow(owner);
DEOPT_IF(!LOCK_OBJECT(owner_o), STORE_ATTR);
char *addr = (char *)owner_o + index;
STAT_INC(STORE_ATTR, hit);
PyObject *old_value = *(PyObject **)addr;
*(PyObject **)addr = PyStackRef_AsPyObjectSteal(value);
FT_ATOMIC_STORE_PTR_RELEASE(*(PyObject **)addr, PyStackRef_AsPyObjectSteal(value));
UNLOCK_OBJECT(owner_o);
Py_XDECREF(old_value);
PyStackRef_CLOSE(owner);
}
@ -7441,7 +7450,7 @@
uint32_t type_version = read_u32(&this_instr[2].cache);
PyTypeObject *tp = Py_TYPE(PyStackRef_AsPyObjectBorrow(owner));
assert(type_version != 0);
DEOPT_IF(tp->tp_version_tag != type_version, STORE_ATTR);
DEOPT_IF(FT_ATOMIC_LOAD_UINT_RELAXED(tp->tp_version_tag) != type_version, STORE_ATTR);
}
// _STORE_ATTR_WITH_HINT
{
@ -7451,18 +7460,35 @@
assert(Py_TYPE(owner_o)->tp_flags & Py_TPFLAGS_MANAGED_DICT);
PyDictObject *dict = _PyObject_GetManagedDict(owner_o);
DEOPT_IF(dict == NULL, STORE_ATTR);
DEOPT_IF(!LOCK_OBJECT(dict), STORE_ATTR);
#ifdef Py_GIL_DISABLED
if (dict != _PyObject_GetManagedDict(owner_o)) {
UNLOCK_OBJECT(dict);
DEOPT_IF(true, STORE_ATTR);
}
#endif
assert(PyDict_CheckExact((PyObject *)dict));
PyObject *name = GETITEM(FRAME_CO_NAMES, oparg);
DEOPT_IF(hint >= (size_t)dict->ma_keys->dk_nentries, STORE_ATTR);
DEOPT_IF(!DK_IS_UNICODE(dict->ma_keys), STORE_ATTR);
if (hint >= (size_t)dict->ma_keys->dk_nentries ||
!DK_IS_UNICODE(dict->ma_keys)) {
UNLOCK_OBJECT(dict);
DEOPT_IF(true, STORE_ATTR);
}
PyDictUnicodeEntry *ep = DK_UNICODE_ENTRIES(dict->ma_keys) + hint;
DEOPT_IF(ep->me_key != name, STORE_ATTR);
if (ep->me_key != name) {
UNLOCK_OBJECT(dict);
DEOPT_IF(true, STORE_ATTR);
}
PyObject *old_value = ep->me_value;
DEOPT_IF(old_value == NULL, STORE_ATTR);
if (old_value == NULL) {
UNLOCK_OBJECT(dict);
DEOPT_IF(true, STORE_ATTR);
}
_PyFrame_SetStackPointer(frame, stack_pointer);
_PyDict_NotifyEvent(tstate->interp, PyDict_EVENT_MODIFIED, dict, name, PyStackRef_AsPyObjectBorrow(value));
stack_pointer = _PyFrame_GetStackPointer(frame);
ep->me_value = PyStackRef_AsPyObjectSteal(value);
FT_ATOMIC_STORE_PTR_RELEASE(ep->me_value, PyStackRef_AsPyObjectSteal(value));
UNLOCK_OBJECT(dict);
// old_value should be DECREFed after GC track checking is done, if not, it could raise a segmentation fault,
// when dict only holds the strong reference to value in ep->me_value.
Py_XDECREF(old_value);
@ -7815,7 +7841,7 @@
uint32_t type_version = read_u32(&this_instr[2].cache);
PyTypeObject *tp = Py_TYPE(PyStackRef_AsPyObjectBorrow(owner));
assert(type_version != 0);
DEOPT_IF(tp->tp_version_tag != type_version, TO_BOOL);
DEOPT_IF(FT_ATOMIC_LOAD_UINT_RELAXED(tp->tp_version_tag) != type_version, TO_BOOL);
}
// _REPLACE_WITH_TRUE
{