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bpo-44889: Specialize LOAD_METHOD with PEP 659 adaptive interpreter (GH-27722)

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Adds four new instructions:

* LOAD_METHOD_ADAPTIVE
* LOAD_METHOD_CACHED
* LOAD_METHOD_MODULE
* LOAD_METHOD_CLASS
This commit is contained in:
Ken Jin 2021-08-17 22:55:55 +08:00 • committed by GitHub
parent fcd651d16f
commit 96346cb6d0
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GPG key ID: 4AEE18F83AFDEB23
7 changed files with 351 additions and 46 deletions
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190
Python/specialize.c
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@ -121,6 +121,7 @@ _Py_GetSpecializationStats(void) {
int err = 0;
err += add_stat_dict(stats, LOAD_ATTR, "load_attr");
err += add_stat_dict(stats, LOAD_GLOBAL, "load_global");
err += add_stat_dict(stats, LOAD_GLOBAL, "load_method");
err += add_stat_dict(stats, BINARY_SUBSCR, "binary_subscr");
err += add_stat_dict(stats, STORE_ATTR, "store_attr");
if (err < 0) {
@ -175,6 +176,7 @@ _Py_PrintSpecializationStats(void)
#endif
print_stats(out, &_specialization_stats[LOAD_ATTR], "load_attr");
print_stats(out, &_specialization_stats[LOAD_GLOBAL], "load_global");
print_stats(out, &_specialization_stats[LOAD_METHOD], "load_method");
print_stats(out, &_specialization_stats[BINARY_SUBSCR], "binary_subscr");
print_stats(out, &_specialization_stats[STORE_ATTR], "store_attr");
if (out != stderr) {
@ -223,6 +225,7 @@ get_cache_count(SpecializedCacheOrInstruction *quickened) {
static uint8_t adaptive_opcodes[256] = {
[LOAD_ATTR] = LOAD_ATTR_ADAPTIVE,
[LOAD_GLOBAL] = LOAD_GLOBAL_ADAPTIVE,
[LOAD_METHOD] = LOAD_METHOD_ADAPTIVE,
[BINARY_SUBSCR] = BINARY_SUBSCR_ADAPTIVE,
[STORE_ATTR] = STORE_ATTR_ADAPTIVE,
};
@ -231,6 +234,7 @@ static uint8_t adaptive_opcodes[256] = {
static uint8_t cache_requirements[256] = {
[LOAD_ATTR] = 2, /* _PyAdaptiveEntry and _PyAttrCache */
[LOAD_GLOBAL] = 2, /* _PyAdaptiveEntry and _PyLoadGlobalCache */
[LOAD_METHOD] = 3, /* _PyAdaptiveEntry, _PyAttrCache and _PyObjectCache */
[BINARY_SUBSCR] = 0,
[STORE_ATTR] = 2, /* _PyAdaptiveEntry and _PyAttrCache */
};
@ -417,6 +421,15 @@ _Py_Quicken(PyCodeObject *code) {
#define SPEC_FAIL_READ_ONLY 15
#define SPEC_FAIL_AUDITED_SLOT 16
/* Methods */
#define SPEC_FAIL_NEGATIVE_DICTOFFSET 14
#define SPEC_FAIL_IS_ATTR 15
#define SPEC_FAIL_DICT_SUBCLASS 16
#define SPEC_FAIL_BUILTIN_CLASS_METHOD 17
#define SPEC_FAIL_CLASS_METHOD_OBJ 18
#define SPEC_FAIL_NOT_METHOD 19
/* Binary subscr */
#define SPEC_FAIL_LIST_NON_INT_SUBSCRIPT 8
@ -427,7 +440,8 @@ _Py_Quicken(PyCodeObject *code) {
static int
specialize_module_load_attr(
PyObject *owner, _Py_CODEUNIT *instr, PyObject *name,
_PyAdaptiveEntry *cache0, _PyAttrCache *cache1)
_PyAdaptiveEntry *cache0, _PyAttrCache *cache1, int opcode,
int opcode_module)
{
PyModuleObject *m = (PyModuleObject *)owner;
PyObject *value = NULL;
@ -435,39 +449,39 @@ specialize_module_load_attr(
_Py_IDENTIFIER(__getattr__);
PyDictObject *dict = (PyDictObject *)m->md_dict;
if (dict == NULL) {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_NO_DICT);
SPECIALIZATION_FAIL(opcode, SPEC_FAIL_NO_DICT);
return -1;
}
if (dict->ma_keys->dk_kind != DICT_KEYS_UNICODE) {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_NON_STRING_OR_SPLIT);
SPECIALIZATION_FAIL(opcode, SPEC_FAIL_NON_STRING_OR_SPLIT);
return -1;
}
getattr = _PyUnicode_FromId(&PyId___getattr__); /* borrowed */
if (getattr == NULL) {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_OVERRIDDEN);
SPECIALIZATION_FAIL(opcode, SPEC_FAIL_OVERRIDDEN);
PyErr_Clear();
return -1;
}
Py_ssize_t index = _PyDict_GetItemHint(dict, getattr, -1, &value);
assert(index != DKIX_ERROR);
if (index != DKIX_EMPTY) {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_MODULE_ATTR_NOT_FOUND);
SPECIALIZATION_FAIL(opcode, SPEC_FAIL_MODULE_ATTR_NOT_FOUND);
return -1;
}
index = _PyDict_GetItemHint(dict, name, -1, &value);
assert (index != DKIX_ERROR);
if (index != (uint16_t)index) {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_OUT_OF_RANGE);
SPECIALIZATION_FAIL(opcode, SPEC_FAIL_OUT_OF_RANGE);
return -1;
}
uint32_t keys_version = _PyDictKeys_GetVersionForCurrentState(dict);
if (keys_version == 0) {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_OUT_OF_VERSIONS);
SPECIALIZATION_FAIL(opcode, SPEC_FAIL_OUT_OF_VERSIONS);
return -1;
}
cache1->dk_version_or_hint = keys_version;
cache0->index = (uint16_t)index;
*instr = _Py_MAKECODEUNIT(LOAD_ATTR_MODULE, _Py_OPARG(*instr));
*instr = _Py_MAKECODEUNIT(opcode_module, _Py_OPARG(*instr));
return 0;
}
@ -482,6 +496,8 @@ typedef enum {
OBJECT_SLOT, /* Is an object slot descriptor */
OTHER_SLOT, /* Is a slot descriptor of another type */
NON_OVERRIDING, /* Is another non-overriding descriptor, and is an instance of an immutable class*/
BUILTIN_CLASSMETHOD, /* Builtin methods with METH_CLASS */
PYTHON_CLASSMETHOD, /* Python classmethod(func) object */
NON_DESCRIPTOR, /* Is not a descriptor, and is an instance of an immutable class */
MUTABLE, /* Instance of a mutable class; might, or might not, be a descriptor */
ABSENT, /* Attribute is not present on the class */
@ -537,6 +553,12 @@ analyze_descriptor(PyTypeObject *type, PyObject *name, PyObject **descr, int sto
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;
@ -549,7 +571,8 @@ specialize_dict_access(
_PyAdaptiveEntry *cache0, _PyAttrCache *cache1,
int base_op, int split_op, int hint_op)
{
assert(kind == NON_OVERRIDING || kind == NON_DESCRIPTOR || kind == ABSENT);
assert(kind == NON_OVERRIDING || kind == NON_DESCRIPTOR || kind == ABSENT ||
kind == BUILTIN_CLASSMETHOD || kind == PYTHON_CLASSMETHOD);
// No desciptor, or non overriding.
if (type->tp_dictoffset < 0) {
SPECIALIZATION_FAIL(base_op, SPEC_FAIL_OUT_OF_RANGE);
@ -608,6 +631,8 @@ specialize_dict_access(
/* No attribute in instance dictionary */
switch(kind) {
case NON_OVERRIDING:
case BUILTIN_CLASSMETHOD:
case PYTHON_CLASSMETHOD:
SPECIALIZATION_FAIL(base_op, SPEC_FAIL_NON_OVERRIDING_DESCRIPTOR);
return 0;
case NON_DESCRIPTOR:
@ -628,7 +653,8 @@ _Py_Specialize_LoadAttr(PyObject *owner, _Py_CODEUNIT *instr, PyObject *name, Sp
_PyAdaptiveEntry *cache0 = &cache->adaptive;
_PyAttrCache *cache1 = &cache[-1].attr;
if (PyModule_CheckExact(owner)) {
int err = specialize_module_load_attr(owner, instr, name, cache0, cache1);
int err = specialize_module_load_attr(owner, instr, name, cache0, cache1,
LOAD_ATTR, LOAD_ATTR_MODULE);
if (err) {
goto fail;
}
@ -690,6 +716,8 @@ _Py_Specialize_LoadAttr(PyObject *owner, _Py_CODEUNIT *instr, PyObject *name, Sp
case GETSET_OVERRIDDEN:
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_OVERRIDDEN);
goto fail;
case BUILTIN_CLASSMETHOD:
case PYTHON_CLASSMETHOD:
case NON_OVERRIDING:
case NON_DESCRIPTOR:
case ABSENT:
@ -769,6 +797,8 @@ _Py_Specialize_StoreAttr(PyObject *owner, _Py_CODEUNIT *instr, PyObject *name, S
case GETSET_OVERRIDDEN:
SPECIALIZATION_FAIL(STORE_ATTR, SPEC_FAIL_OVERRIDDEN);
goto fail;
case BUILTIN_CLASSMETHOD:
case PYTHON_CLASSMETHOD:
case NON_OVERRIDING:
case NON_DESCRIPTOR:
case ABSENT:
@ -798,6 +828,146 @@ _Py_Specialize_StoreAttr(PyObject *owner, _Py_CODEUNIT *instr, PyObject *name, S
}
// Please collect stats carefully before and after modifying. A subtle change
// can cause a significant drop in cache hits. A possible test is
// python.exe -m test_typing test_re test_dis test_zlib.
int
_Py_Specialize_LoadMethod(PyObject *owner, _Py_CODEUNIT *instr, PyObject *name, SpecializedCacheEntry *cache)
{
_PyAdaptiveEntry *cache0 = &cache->adaptive;
_PyAttrCache *cache1 = &cache[-1].attr;
_PyObjectCache *cache2 = &cache[-2].obj;
PyTypeObject *owner_cls = Py_TYPE(owner);
PyDictObject *owner_dict = NULL;
if (PyModule_CheckExact(owner)) {
int err = specialize_module_load_attr(owner, instr, name, cache0, cache1,
LOAD_METHOD, LOAD_METHOD_MODULE);
if (err) {
goto fail;
}
goto success;
}
if (owner_cls->tp_dict == NULL) {
if (PyType_Ready(owner_cls) < 0) {
return -1;
}
}
if (Py_TYPE(owner_cls)->tp_dictoffset < 0) {
SPECIALIZATION_FAIL(LOAD_METHOD, SPEC_FAIL_OUT_OF_RANGE);
goto fail;
}
// Technically this is fine for bound method calls, but it's uncommon and
// slightly slower at runtime to get dict.
if (owner_cls->tp_dictoffset < 0) {
SPECIALIZATION_FAIL(LOAD_METHOD, SPEC_FAIL_NEGATIVE_DICTOFFSET);
goto fail;
}
PyObject **owner_dictptr = _PyObject_GetDictPtr(owner);
int owner_has_dict = (owner_dictptr != NULL && *owner_dictptr != NULL);
owner_dict = owner_has_dict ? (PyDictObject *)*owner_dictptr : NULL;
// Make sure dict doesn't get GC-ed halfway.
Py_XINCREF(owner_dict);
// Check for classmethods.
int owner_is_class = PyType_Check(owner);
owner_cls = owner_is_class ? (PyTypeObject *)owner : owner_cls;
if ((owner_cls->tp_flags & Py_TPFLAGS_VALID_VERSION_TAG) == 0 ||
owner_cls->tp_version_tag == 0) {
SPECIALIZATION_FAIL(LOAD_METHOD, SPEC_FAIL_OUT_OF_VERSIONS);
goto fail;
}
PyObject *descr = NULL;
DesciptorClassification kind = 0;
kind = analyze_descriptor(owner_cls, name, &descr, 0);
// Store the version right away, in case it's modified halfway through.
cache1->tp_version = owner_cls->tp_version_tag;
assert(descr != NULL || kind == ABSENT || kind == GETSET_OVERRIDDEN);
switch (kind) {
case METHOD:
break;
case BUILTIN_CLASSMETHOD:
SPECIALIZATION_FAIL(LOAD_METHOD, SPEC_FAIL_BUILTIN_CLASS_METHOD);
goto fail;
case PYTHON_CLASSMETHOD:
SPECIALIZATION_FAIL(LOAD_METHOD, SPEC_FAIL_CLASS_METHOD_OBJ);
goto fail;
default:
SPECIALIZATION_FAIL(LOAD_METHOD, SPEC_FAIL_NOT_METHOD);
goto fail;
}
assert(kind == METHOD);
// If o.__dict__ changes, the method might be found in o.__dict__
// instead of old type lookup. So record o.__dict__'s keys.
uint32_t keys_version = UINT32_MAX;
if (owner_has_dict) {
// _PyDictKeys_GetVersionForCurrentState isn't accurate for
// custom dict subclasses at the moment.
if (!PyDict_CheckExact(owner_dict)) {
SPECIALIZATION_FAIL(LOAD_METHOD, SPEC_FAIL_DICT_SUBCLASS);
goto fail;
}
assert(PyUnicode_CheckExact(name));
Py_hash_t hash = PyObject_Hash(name);
if (hash == -1) {
return -1;
}
PyObject *value = NULL;
if (!owner_is_class) {
// Instance methods shouldn't be in o.__dict__. That makes
// it an attribute.
Py_ssize_t ix = _Py_dict_lookup(owner_dict, name, hash, &value);
assert(ix != DKIX_ERROR);
if (ix != DKIX_EMPTY) {
SPECIALIZATION_FAIL(LOAD_METHOD, SPEC_FAIL_IS_ATTR);
goto fail;
}
}
keys_version = _PyDictKeys_GetVersionForCurrentState(owner_dict);
if (keys_version == 0) {
SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_OUT_OF_VERSIONS);
goto fail;
}
// Fall through.
} // Else owner is maybe a builtin with no dict, or __slots__. Doesn't matter.
/* `descr` is borrowed. Just check tp_version_tag before accessing in case
* it's deleted. This is safe for methods (even inherited ones from super
* classes!) as long as tp_version_tag is validated for two main reasons:
*
* 1. The class will always hold a reference to the method so it will
* usually not be GC-ed. Should it be deleted in Python, e.g.
* `del obj.meth`, tp_version_tag will be invalidated, because of reason 2.
*
* 2. The pre-existing type method cache (MCACHE) uses the same principles
* of caching a borrowed descriptor. It does all the heavy lifting for us.
* E.g. it invalidates on any MRO modification, on any type object
* change along said MRO, etc. (see PyType_Modified usages in typeobject.c).
* The type method cache has been working since Python 2.6 and it's
* battle-tested.
*/
cache2->obj = descr;
cache1->dk_version_or_hint = keys_version;
*instr = _Py_MAKECODEUNIT(owner_is_class ? LOAD_METHOD_CLASS :
LOAD_METHOD_CACHED, _Py_OPARG(*instr));
// Fall through.
success:
Py_XDECREF(owner_dict);
STAT_INC(LOAD_METHOD, specialization_success);
assert(!PyErr_Occurred());
cache0->counter = saturating_start();
return 0;
fail:
Py_XDECREF(owner_dict);
STAT_INC(LOAD_METHOD, specialization_failure);
assert(!PyErr_Occurred());
cache_backoff(cache0);
return 0;
}
int
_Py_Specialize_LoadGlobal(
PyObject *globals, PyObject *builtins,