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bpo-44337: Improve LOAD_ATTR specialization #26759

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1 change: 1 addition & 0 deletions Include/internal/pycore_code.h
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Original file line number Diff line number Diff line change
@@ -336,6 +336,7 @@ typedef struct _stats {
uint64_t deferred;
uint64_t miss;
uint64_t deopt;
#if SPECIALIZATION_STATS_DETAILED
PyObject *miss_types;
#endif
2 changes: 2 additions & 0 deletions Python/ceval.c
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Expand Up @@ -2805,6 +2805,7 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, PyFrameObject *f, int throwflag)

case TARGET(LOAD_GLOBAL): {
PREDICTED(LOAD_GLOBAL);
PyObject *name = GETITEM(names, oparg);
PyObject *v;
if (PyDict_CheckExact(GLOBALS())
Expand Down Expand Up @@ -3289,6 +3290,7 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, PyFrameObject *f, int throwflag)

case TARGET(LOAD_ATTR): {
PREDICTED(LOAD_ATTR);
PyObject *name = GETITEM(names, oparg);
PyObject *owner = TOP();
PyObject *res = PyObject_GetAttr(owner, name);
Expand Down
248 changes: 176 additions & 72 deletions Python/specialize.c
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Expand Up @@ -47,6 +47,7 @@ print_stats(SpecializationStats *stats, const char *name)
PRINT_STAT(name, deferred);
PRINT_STAT(name, miss);
PRINT_STAT(name, deopt);
#if SPECIALIZATION_STATS_DETAILED
if (stats->miss_types == NULL) {
return;
Expand Down @@ -302,6 +303,8 @@ _Py_Quicken(PyCodeObject *code) {
return 0;
}

static int
specialize_module_load_attr(
PyObject *owner, _Py_CODEUNIT *instr, PyObject *name,
Expand Down Expand Up @@ -349,6 +352,68 @@ specialize_module_load_attr(
return 0;
}

int
_Py_Specialize_LoadAttr(PyObject *owner, _Py_CODEUNIT *instr, PyObject *name, SpecializedCacheEntry *cache)
{
Expand All @@ -362,94 +427,134 @@ _Py_Specialize_LoadAttr(PyObject *owner, _Py_CODEUNIT *instr, PyObject *name, Sp
goto success;
}
PyTypeObject *type = Py_TYPE(owner);
if (type->tp_getattro != PyObject_GenericGetAttr) {
SPECIALIZATION_FAIL(LOAD_ATTR, Py_TYPE(owner), name, "__getattribute__ overridden");
goto fail;
}
if (type->tp_dict == NULL) {
if (PyType_Ready(type) < 0) {
return -1;
}
}
PyObject *descr = _PyType_Lookup(type, name);
if (descr != NULL) {
// We found an attribute with a data-like descriptor.
PyTypeObject *dtype = Py_TYPE(descr);
if (dtype != &PyMemberDescr_Type) {
SPECIALIZATION_FAIL(LOAD_ATTR, Py_TYPE(owner), name, "not a member descriptor");
goto fail;
}
// It's a slot
PyMemberDescrObject *member = (PyMemberDescrObject *)descr;
struct PyMemberDef *dmem = member->d_member;
if (dmem->type != T_OBJECT_EX) {
SPECIALIZATION_FAIL(LOAD_ATTR, Py_TYPE(owner), name, "non-object slot");
goto fail;
}
Py_ssize_t offset = dmem->offset;
if (offset != (uint16_t)offset) {
SPECIALIZATION_FAIL(LOAD_ATTR, Py_TYPE(owner), name, "offset out of range");
goto fail;
}
assert(offset > 0);
cache0->index = (uint16_t)offset;
cache1->tp_version = type->tp_version_tag;
*instr = _Py_MAKECODEUNIT(LOAD_ATTR_SLOT, _Py_OPARG(*instr));
goto success;
}
// No desciptor
if (type->tp_dictoffset <= 0) {
SPECIALIZATION_FAIL(LOAD_ATTR, Py_TYPE(owner), name, "no dict or negative offset");
goto fail;
}
PyObject **dictptr = (PyObject **) ((char *)owner + type->tp_dictoffset);
if (*dictptr == NULL || !PyDict_CheckExact(*dictptr)) {
SPECIALIZATION_FAIL(LOAD_ATTR, Py_TYPE(owner), name, "no dict or not a dict");
goto fail;
}
// We found an instance with a __dict__.
PyDictObject *dict = (PyDictObject *)*dictptr;
if ((type->tp_flags & Py_TPFLAGS_HEAPTYPE)
&& dict->ma_keys == ((PyHeapTypeObject*)type)->ht_cached_keys
) {
// Keys are shared
assert(PyUnicode_CheckExact(name));
Py_hash_t hash = PyObject_Hash(name);
if (hash == -1) {
return -1;
}
PyObject *value;
Py_ssize_t index = _Py_dict_lookup(dict, name, hash, &value);
assert (index != DKIX_ERROR);
if (index != (uint16_t)index) {
SPECIALIZATION_FAIL(LOAD_ATTR, Py_TYPE(owner), name, "index out of range");
goto fail;
}
uint32_t keys_version = _PyDictKeys_GetVersionForCurrentState(dict);
if (keys_version == 0) {
SPECIALIZATION_FAIL(LOAD_ATTR, Py_TYPE(owner), name, "no more key versions");
goto fail;
}
cache1->dk_version_or_hint = keys_version;
cache1->tp_version = type->tp_version_tag;
cache0->index = (uint16_t)index;
*instr = _Py_MAKECODEUNIT(LOAD_ATTR_SPLIT_KEYS, _Py_OPARG(*instr));
goto success;
}
else {
PyObject *value = NULL;
Py_ssize_t hint =
_PyDict_GetItemHint(dict, name, -1, &value);
if (hint != (uint32_t)hint) {
SPECIALIZATION_FAIL(LOAD_ATTR, Py_TYPE(owner), name, "hint out of range");
goto fail;
}
cache1->dk_version_or_hint = (uint32_t)hint;
cache1->tp_version = type->tp_version_tag;
*instr = _Py_MAKECODEUNIT(LOAD_ATTR_WITH_HINT, _Py_OPARG(*instr));
goto success;
}

fail:
STAT_INC(LOAD_ATTR, specialization_failure);
assert(!PyErr_Occurred());
Expand All @@ -462,7 +567,6 @@ _Py_Specialize_LoadAttr(PyObject *owner, _Py_CODEUNIT *instr, PyObject *name, Sp
return 0;
}


int
_Py_Specialize_LoadGlobal(
PyObject *globals, PyObject *builtins,
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