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GH-123040: Specialize shadowed LOAD_ATTR. (GH-123219)

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Mark Shannon 2024-08-23 10:22:35 +01:00 • committed by GitHub
parent 90b6d0e0f8
commit 5d3201fe3f
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7 changed files with 334 additions and 201 deletions
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348
Python/specialize.c
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@ -490,7 +490,7 @@ _PyCode_Quicken(PyCodeObject *code)
#define SPEC_FAIL_ATTR_READ_ONLY 16
#define SPEC_FAIL_ATTR_AUDITED_SLOT 17
#define SPEC_FAIL_ATTR_NOT_MANAGED_DICT 18
#define SPEC_FAIL_ATTR_NON_STRING_OR_SPLIT 19
#define SPEC_FAIL_ATTR_NON_STRING 19
#define SPEC_FAIL_ATTR_MODULE_ATTR_NOT_FOUND 20
#define SPEC_FAIL_ATTR_SHADOWED 21
#define SPEC_FAIL_ATTR_BUILTIN_CLASS_METHOD 22
@ -505,6 +505,8 @@ _PyCode_Quicken(PyCodeObject *code)
#define SPEC_FAIL_ATTR_CLASS_ATTR_SIMPLE 31
#define SPEC_FAIL_ATTR_CLASS_ATTR_DESCRIPTOR 32
#define SPEC_FAIL_ATTR_BUILTIN_CLASS_METHOD_OBJ 33
#define SPEC_FAIL_ATTR_METACLASS_OVERRIDDEN 34
#define SPEC_FAIL_ATTR_SPLIT_DICT 35
/* Binary subscr and store subscr */
@ -647,7 +649,7 @@ specialize_module_load_attr(
return -1;
}
if (dict->ma_keys->dk_kind != DICT_KEYS_UNICODE) {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_ATTR_NON_STRING_OR_SPLIT);
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_ATTR_NON_STRING);
return -1;
}
Py_ssize_t index = _PyDict_LookupIndex(dict, &_Py_ID(__getattr__));
@ -730,6 +732,48 @@ typedef enum {
} DescriptorClassification;
static DescriptorClassification
classify_descriptor(PyObject *descriptor, bool has_getattr)
{
if (descriptor == NULL) {
return ABSENT;
}
PyTypeObject *desc_cls = Py_TYPE(descriptor);
if (!(desc_cls->tp_flags & Py_TPFLAGS_IMMUTABLETYPE)) {
return MUTABLE;
}
if (desc_cls->tp_descr_set) {
if (desc_cls == &PyMemberDescr_Type) {
PyMemberDescrObject *member = (PyMemberDescrObject *)descriptor;
struct PyMemberDef *dmem = member->d_member;
if (dmem->type == Py_T_OBJECT_EX || dmem->type == _Py_T_OBJECT) {
return OBJECT_SLOT;
}
return OTHER_SLOT;
}
if (desc_cls == &PyProperty_Type) {
/* We can't detect at runtime whether an attribute exists
with property. So that means we may have to call
__getattr__. */
return has_getattr ? GETSET_OVERRIDDEN : PROPERTY;
}
return OVERRIDING;
}
if (desc_cls->tp_descr_get) {
if (desc_cls->tp_flags & Py_TPFLAGS_METHOD_DESCRIPTOR) {
return METHOD;
}
if (Py_IS_TYPE(descriptor, &PyClassMethodDescr_Type)) {
return BUILTIN_CLASSMETHOD;
}
if (Py_IS_TYPE(descriptor, &PyClassMethod_Type)) {
return PYTHON_CLASSMETHOD;
}
return NON_OVERRIDING;
}
return NON_DESCRIPTOR;
}
static DescriptorClassification
analyze_descriptor(PyTypeObject *type, PyObject *name, PyObject **descr, int store)
{
@ -783,50 +827,12 @@ analyze_descriptor(PyTypeObject *type, PyObject *name, PyObject **descr, int sto
}
PyObject *descriptor = _PyType_Lookup(type, name);
*descr = descriptor;
if (descriptor == NULL) {
return ABSENT;
}
PyTypeObject *desc_cls = Py_TYPE(descriptor);
if (!(desc_cls->tp_flags & Py_TPFLAGS_IMMUTABLETYPE)) {
return MUTABLE;
}
if (desc_cls->tp_descr_set) {
if (desc_cls == &PyMemberDescr_Type) {
PyMemberDescrObject *member = (PyMemberDescrObject *)descriptor;
struct PyMemberDef *dmem = member->d_member;
if (dmem->type == Py_T_OBJECT_EX || dmem->type == _Py_T_OBJECT) {
return OBJECT_SLOT;
}
return OTHER_SLOT;
}
if (desc_cls == &PyProperty_Type) {
/* We can't detect at runtime whether an attribute exists
with property. So that means we may have to call
__getattr__. */
return has_getattr ? GETSET_OVERRIDDEN : PROPERTY;
}
if (PyUnicode_CompareWithASCIIString(name, "__class__") == 0) {
if (descriptor == _PyType_Lookup(&PyBaseObject_Type, name)) {
return DUNDER_CLASS;
}
}
if (store) {
return OVERRIDING;
if (PyUnicode_CompareWithASCIIString(name, "__class__") == 0) {
if (descriptor == _PyType_Lookup(&PyBaseObject_Type, name)) {
return DUNDER_CLASS;
}
}
if (desc_cls->tp_descr_get) {
if (desc_cls->tp_flags & Py_TPFLAGS_METHOD_DESCRIPTOR) {
return METHOD;
}
if (Py_IS_TYPE(descriptor, &PyClassMethodDescr_Type)) {
return BUILTIN_CLASSMETHOD;
}
if (Py_IS_TYPE(descriptor, &PyClassMethod_Type)) {
return PYTHON_CLASSMETHOD;
}
return NON_OVERRIDING;
}
return NON_DESCRIPTOR;
return classify_descriptor(descriptor, has_getattr);
}
static int
@ -836,7 +842,8 @@ specialize_dict_access(
int base_op, int values_op, int hint_op)
{
assert(kind == NON_OVERRIDING || kind == NON_DESCRIPTOR || kind == ABSENT ||
kind == BUILTIN_CLASSMETHOD || kind == PYTHON_CLASSMETHOD);
kind == BUILTIN_CLASSMETHOD || kind == PYTHON_CLASSMETHOD ||
kind == METHOD);
// No descriptor, or non overriding.
if ((type->tp_flags & Py_TPFLAGS_MANAGED_DICT) == 0) {
SPECIALIZATION_FAIL(base_op, SPEC_FAIL_ATTR_NOT_MANAGED_DICT);
@ -871,7 +878,7 @@ specialize_dict_access(
}
// We found an instance with a __dict__.
if (dict->ma_values) {
SPECIALIZATION_FAIL(base_op, SPEC_FAIL_ATTR_NON_STRING_OR_SPLIT);
SPECIALIZATION_FAIL(base_op, SPEC_FAIL_ATTR_SPLIT_DICT);
return 0;
}
Py_ssize_t index =
@ -894,57 +901,69 @@ static int specialize_attr_loadclassattr(PyObject* owner, _Py_CODEUNIT* instr, P
PyObject* descr, DescriptorClassification kind, bool is_method);
static int specialize_class_load_attr(PyObject* owner, _Py_CODEUNIT* instr, PyObject* name);
void
_Py_Specialize_LoadAttr(_PyStackRef owner_st, _Py_CODEUNIT *instr, PyObject *name)
/* Returns true if instances of obj's class are
* likely to have `name` in their __dict__.
* For objects with inline values, we check in the shared keys.
* For other objects, we check their actual dictionary.
*/
static bool
instance_has_key(PyObject *obj, PyObject* name)
{
PyObject *owner = PyStackRef_AsPyObjectBorrow(owner_st);
PyTypeObject *cls = Py_TYPE(obj);
if ((cls->tp_flags & Py_TPFLAGS_MANAGED_DICT) == 0) {
return false;
}
if (cls->tp_flags & Py_TPFLAGS_INLINE_VALUES) {
PyDictKeysObject *keys = ((PyHeapTypeObject *)cls)->ht_cached_keys;
Py_ssize_t index = _PyDictKeys_StringLookup(keys, name);
return index >= 0;
}
PyDictObject *dict = _PyObject_GetManagedDict(obj);
if (dict == NULL || !PyDict_CheckExact(dict)) {
return false;
}
if (dict->ma_values) {
return false;
}
Py_ssize_t index = _PyDict_LookupIndex(dict, name);
if (index < 0) {
return false;
}
return true;
}
assert(ENABLE_SPECIALIZATION);
assert(_PyOpcode_Caches[LOAD_ATTR] == INLINE_CACHE_ENTRIES_LOAD_ATTR);
static int
specialize_instance_load_attr(PyObject* owner, _Py_CODEUNIT* instr, PyObject* name)
{
_PyAttrCache *cache = (_PyAttrCache *)(instr + 1);
PyTypeObject *type = Py_TYPE(owner);
if (!_PyType_IsReady(type)) {
// We *might* not really need this check, but we inherited it from
// PyObject_GenericGetAttr and friends... and this way we still do the
// right thing if someone forgets to call PyType_Ready(type):
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_OTHER);
goto fail;
}
if (PyModule_CheckExact(owner)) {
if (specialize_module_load_attr(owner, instr, name))
{
goto fail;
}
goto success;
}
if (PyType_Check(owner)) {
if (specialize_class_load_attr(owner, instr, name)) {
goto fail;
}
goto success;
}
bool shadow = instance_has_key(owner, name);
PyObject *descr = NULL;
DescriptorClassification kind = analyze_descriptor(type, name, &descr, 0);
assert(descr != NULL || kind == ABSENT || kind == GETSET_OVERRIDDEN);
if (type_get_version(type, LOAD_ATTR) == 0) {
goto fail;
return -1;
}
switch(kind) {
case OVERRIDING:
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_ATTR_OVERRIDING_DESCRIPTOR);
goto fail;
return -1;
case METHOD:
{
if (shadow) {
goto try_instance;
}
int oparg = instr->op.arg;
if (oparg & 1) {
if (specialize_attr_loadclassattr(owner, instr, name, descr, kind, true)) {
goto success;
return 0;
}
else {
return -1;
}
}
else {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_ATTR_METHOD);
}
goto fail;
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_ATTR_METHOD);
return -1;
}
case PROPERTY:
{
@ -953,29 +972,29 @@ _Py_Specialize_LoadAttr(_PyStackRef owner_st, _Py_CODEUNIT *instr, PyObject *nam
PyObject *fget = ((_PyPropertyObject *)descr)->prop_get;
if (fget == NULL) {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_EXPECTED_ERROR);
goto fail;
return -1;
}
if (!Py_IS_TYPE(fget, &PyFunction_Type)) {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_ATTR_PROPERTY_NOT_PY_FUNCTION);
goto fail;
return -1;
}
if (!function_check_args(fget, 1, LOAD_ATTR)) {
goto fail;
return -1;
}
if (instr->op.arg & 1) {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_ATTR_METHOD);
goto fail;
return -1;
}
if (_PyInterpreterState_GET()->eval_frame) {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_OTHER);
goto fail;
return -1;
}
assert(type->tp_version_tag != 0);
write_u32(lm_cache->type_version, type->tp_version_tag);
/* borrowed */
write_obj(lm_cache->descr, fget);
instr->op.code = LOAD_ATTR_PROPERTY;
goto success;
return 0;
}
case OBJECT_SLOT:
{
@ -984,22 +1003,22 @@ _Py_Specialize_LoadAttr(_PyStackRef owner_st, _Py_CODEUNIT *instr, PyObject *nam
Py_ssize_t offset = dmem->offset;
if (!PyObject_TypeCheck(owner, member->d_common.d_type)) {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_EXPECTED_ERROR);
goto fail;
return -1;
}
if (dmem->flags & Py_AUDIT_READ) {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_ATTR_AUDITED_SLOT);
goto fail;
return -1;
}
if (offset != (uint16_t)offset) {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_OUT_OF_RANGE);
goto fail;
return -1;
}
assert(dmem->type == Py_T_OBJECT_EX || dmem->type == _Py_T_OBJECT);
assert(offset > 0);
cache->index = (uint16_t)offset;
write_u32(cache->version, type->tp_version_tag);
instr->op.code = LOAD_ATTR_SLOT;
goto success;
return 0;
}
case DUNDER_CLASS:
{
@ -1008,83 +1027,115 @@ _Py_Specialize_LoadAttr(_PyStackRef owner_st, _Py_CODEUNIT *instr, PyObject *nam
cache->index = (uint16_t)offset;
write_u32(cache->version, type->tp_version_tag);
instr->op.code = LOAD_ATTR_SLOT;
goto success;
return 0;
}
case OTHER_SLOT:
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_ATTR_NON_OBJECT_SLOT);
goto fail;
return -1;
case MUTABLE:
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_ATTR_MUTABLE_CLASS);
goto fail;
return -1;
case GETSET_OVERRIDDEN:
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_OVERRIDDEN);
goto fail;
return -1;
case GETATTRIBUTE_IS_PYTHON_FUNCTION:
{
assert(type->tp_getattro == _Py_slot_tp_getattro);
assert(Py_IS_TYPE(descr, &PyFunction_Type));
_PyLoadMethodCache *lm_cache = (_PyLoadMethodCache *)(instr + 1);
if (!function_check_args(descr, 2, LOAD_ATTR)) {
goto fail;
return -1;
}
if (instr->op.arg & 1) {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_ATTR_METHOD);
goto fail;
return -1;
}
uint32_t version = function_get_version(descr, LOAD_ATTR);
if (version == 0) {
goto fail;
return -1;
}
if (_PyInterpreterState_GET()->eval_frame) {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_OTHER);
goto fail;
return -1;
}
write_u32(lm_cache->keys_version, version);
/* borrowed */
write_obj(lm_cache->descr, descr);
write_u32(lm_cache->type_version, type->tp_version_tag);
instr->op.code = LOAD_ATTR_GETATTRIBUTE_OVERRIDDEN;
goto success;
return 0;
}
case BUILTIN_CLASSMETHOD:
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_ATTR_BUILTIN_CLASS_METHOD_OBJ);
goto fail;
case PYTHON_CLASSMETHOD:
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_ATTR_CLASS_METHOD_OBJ);
goto fail;
case NON_OVERRIDING:
SPECIALIZATION_FAIL(LOAD_ATTR,
(type->tp_flags & Py_TPFLAGS_MANAGED_DICT) ?
SPEC_FAIL_ATTR_CLASS_ATTR_DESCRIPTOR :
SPEC_FAIL_ATTR_NOT_MANAGED_DICT);
goto fail;
if (shadow) {
goto try_instance;
}
return -1;
case NON_DESCRIPTOR:
if (shadow) {
goto try_instance;
}
if ((instr->op.arg & 1) == 0) {
if (specialize_attr_loadclassattr(owner, instr, name, descr, kind, false)) {
goto success;
return 0;
}
}
else {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_ATTR_CLASS_ATTR_SIMPLE);
}
goto fail;
return -1;
case ABSENT:
if (specialize_dict_access(owner, instr, type, kind, name, LOAD_ATTR,
LOAD_ATTR_INSTANCE_VALUE, LOAD_ATTR_WITH_HINT))
{
goto success;
if (shadow) {
goto try_instance;
}
return 0;
}
Py_UNREACHABLE();
try_instance:
if (specialize_dict_access(owner, instr, type, kind, name, LOAD_ATTR,
LOAD_ATTR_INSTANCE_VALUE, LOAD_ATTR_WITH_HINT))
{
return 0;
}
return -1;
}
void
_Py_Specialize_LoadAttr(_PyStackRef owner_st, _Py_CODEUNIT *instr, PyObject *name)
{
_PyAttrCache *cache = (_PyAttrCache *)(instr + 1);
PyObject *owner = PyStackRef_AsPyObjectBorrow(owner_st);
assert(ENABLE_SPECIALIZATION);
assert(_PyOpcode_Caches[LOAD_ATTR] == INLINE_CACHE_ENTRIES_LOAD_ATTR);
PyTypeObject *type = Py_TYPE(owner);
bool fail;
if (!_PyType_IsReady(type)) {
// We *might* not really need this check, but we inherited it from
// PyObject_GenericGetAttr and friends... and this way we still do the
// right thing if someone forgets to call PyType_Ready(type):
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_OTHER);
fail = true;
}
else if (PyModule_CheckExact(owner)) {
fail = specialize_module_load_attr(owner, instr, name);
}
else if (PyType_Check(owner)) {
fail = specialize_class_load_attr(owner, instr, name);
}
else {
fail = specialize_instance_load_attr(owner, instr, name);
}
if (fail) {
STAT_INC(LOAD_ATTR, failure);
assert(!PyErr_Occurred());
instr->op.code = LOAD_ATTR;
cache->counter = adaptive_counter_backoff(cache->counter);
}
else {
STAT_INC(LOAD_ATTR, success);
assert(!PyErr_Occurred());
cache->counter = adaptive_counter_cooldown();
}
fail:
STAT_INC(LOAD_ATTR, failure);
assert(!PyErr_Occurred());
instr->op.code = LOAD_ATTR;
cache->counter = adaptive_counter_backoff(cache->counter);
return;
success:
STAT_INC(LOAD_ATTR, success);
assert(!PyErr_Occurred());
cache->counter = adaptive_counter_cooldown();
}
void
@ -1230,23 +1281,52 @@ static int
specialize_class_load_attr(PyObject *owner, _Py_CODEUNIT *instr,
PyObject *name)
{
assert(PyType_Check(owner));
PyTypeObject *cls = (PyTypeObject *)owner;
_PyLoadMethodCache *cache = (_PyLoadMethodCache *)(instr + 1);
if (!PyType_CheckExact(owner) || _PyType_Lookup(Py_TYPE(owner), name)) {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_ATTR_METACLASS_ATTRIBUTE);
if (Py_TYPE(cls)->tp_getattro != _Py_type_getattro) {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_ATTR_METACLASS_OVERRIDDEN);
return -1;
}
PyObject *metadescriptor = _PyType_Lookup(Py_TYPE(cls), name);
DescriptorClassification metakind = classify_descriptor(metadescriptor, false);
switch (metakind) {
case METHOD:
case NON_DESCRIPTOR:
case NON_OVERRIDING:
case BUILTIN_CLASSMETHOD:
case PYTHON_CLASSMETHOD:
case ABSENT:
break;
default:
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_ATTR_METACLASS_ATTRIBUTE);
return -1;
}
PyObject *descr = NULL;
DescriptorClassification kind = 0;
kind = analyze_descriptor((PyTypeObject *)owner, name, &descr, 0);
if (type_get_version((PyTypeObject *)owner, LOAD_ATTR) == 0) {
kind = analyze_descriptor(cls, name, &descr, 0);
if (type_get_version(cls, LOAD_ATTR) == 0) {
return -1;
}
bool metaclass_check = false;
if ((Py_TYPE(cls)->tp_flags & Py_TPFLAGS_IMMUTABLETYPE) == 0) {
metaclass_check = true;
if (type_get_version(Py_TYPE(cls), LOAD_ATTR) == 0) {
return -1;
}
}
switch (kind) {
case METHOD:
case NON_DESCRIPTOR:
write_u32(cache->type_version, ((PyTypeObject *)owner)->tp_version_tag);
write_u32(cache->type_version, cls->tp_version_tag);
write_obj(cache->descr, descr);
instr->op.code = LOAD_ATTR_CLASS;
if (metaclass_check) {
write_u32(cache->keys_version, Py_TYPE(cls)->tp_version_tag);
instr->op.code = LOAD_ATTR_CLASS_WITH_METACLASS_CHECK;
}
else {
instr->op.code = LOAD_ATTR_CLASS;
}
return 0;
#ifdef Py_STATS
case ABSENT:
@ -1273,11 +1353,7 @@ PyObject *descr, DescriptorClassification kind, bool is_method)
assert((is_method && kind == METHOD) || (!is_method && kind == NON_DESCRIPTOR));
if (owner_cls->tp_flags & Py_TPFLAGS_INLINE_VALUES) {
PyDictKeysObject *keys = ((PyHeapTypeObject *)owner_cls)->ht_cached_keys;
Py_ssize_t index = _PyDictKeys_StringLookup(keys, name);
if (index != DKIX_EMPTY) {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_ATTR_SHADOWED);
return 0;
}
assert(_PyDictKeys_StringLookup(keys, name) < 0);
uint32_t keys_version = _PyDictKeys_GetVersionForCurrentState(
_PyInterpreterState_GET(), keys);
if (keys_version == 0) {