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Shrink the LOAD_METHOD cache by one codeunit. (#93537)

This commit is contained in:
Mark Shannon 2022-06-07 10:28:53 +01:00 committed by GitHub
parent 75ceae05c1
commit f012df706c
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GPG Key ID: 4AEE18F83AFDEB23
8 changed files with 12 additions and 18 deletions
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1
Include/internal/pycore_code.h
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@ -65,7 +65,6 @@ typedef struct {
typedef struct {
_Py_CODEUNIT counter;
_Py_CODEUNIT type_version[2];
_Py_CODEUNIT dict_offset;
_Py_CODEUNIT keys_version[2];
_Py_CODEUNIT descr[4];
} _PyLoadMethodCache;

2
Include/internal/pycore_opcode.h generated
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@ -49,7 +49,7 @@ const uint8_t _PyOpcode_Caches[256] = {
[COMPARE_OP] = 2,
[LOAD_GLOBAL] = 5,
[BINARY_OP] = 1,
[LOAD_METHOD] = 10,
[LOAD_METHOD] = 9,
[CALL] = 4,
};

3
Lib/importlib/_bootstrap_external.py
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@ -407,6 +407,7 @@ _code_type = type(_write_atomic.__code__)
# Python 3.12a1 3500 (Remove PRECALL opcode)
# Python 3.12a1 3501 (YIELD_VALUE oparg == stack_depth)
# Python 3.12a1 3502 (LOAD_FAST_CHECK, no NULL-check in LOAD_FAST)
# Python 3.12a1 3503 (Shrink LOAD_METHOD cache)
# Python 3.13 will start with 3550
@ -420,7 +421,7 @@ _code_type = type(_write_atomic.__code__)
# Whenever MAGIC_NUMBER is changed, the ranges in the magic_values array
# in PC/launcher.c must also be updated.
MAGIC_NUMBER = (3502).to_bytes(2, 'little') + b'\r\n'
MAGIC_NUMBER = (3503).to_bytes(2, 'little') + b'\r\n'
_RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little') # For import.c

1
Lib/opcode.py
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@ -383,7 +383,6 @@ _cache_format = {
"LOAD_METHOD": {
"counter": 1,
"type_version": 2,
"dict_offset": 1,
"keys_version": 2,
"descr": 4,
},

2
Lib/test/test_dis.py
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@ -1047,7 +1047,7 @@ class DisTests(DisTestBase):
for cache in caches:
self.assertRegex(cache, pattern)
self.assertEqual(caches.count(""), 8)
self.assertEqual(len(caches), 23)
self.assertEqual(len(caches), 22)
class DisWithFileTests(DisTests):

1
Misc/NEWS.d/next/Core and Builtins/2022-06-06-14-28-24.gh-issue-93533.lnC0CC.rst Normal file
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@ -0,0 +1 @@
Reduce the size of the inline cache for ``LOAD_METHOD`` by 2 bytes.

11
Python/ceval.c
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@ -4581,12 +4581,9 @@ handle_eval_breaker:
DEOPT_IF(self_cls->tp_version_tag != read_u32(cache->type_version),
LOAD_METHOD);
/* Treat index as a signed 16 bit value */
int dictoffset = *(int16_t *)&cache->dict_offset;
int dictoffset = self_cls->tp_dictoffset;
assert(dictoffset > 0);
PyDictObject **dictptr = (PyDictObject**)(((char *)self)+dictoffset);
assert(
dictoffset == MANAGED_DICT_OFFSET ||
(dictoffset == self_cls->tp_dictoffset && dictoffset > 0)
);
PyDictObject *dict = *dictptr;
DEOPT_IF(dict == NULL, LOAD_METHOD);
DEOPT_IF(dict->ma_keys->dk_version != read_u32(cache->keys_version),
@ -4628,9 +4625,9 @@ handle_eval_breaker:
_PyLoadMethodCache *cache = (_PyLoadMethodCache *)next_instr;
uint32_t type_version = read_u32(cache->type_version);
DEOPT_IF(self_cls->tp_version_tag != type_version, LOAD_METHOD);
int dictoffset = cache->dict_offset;
int dictoffset = self_cls->tp_dictoffset;
assert(dictoffset > 0);
PyObject *dict = *(PyObject **)((char *)self + dictoffset);
assert(dictoffset == self_cls->tp_dictoffset && dictoffset > 0);
/* This object has a __dict__, just not yet created */
DEOPT_IF(dict != NULL, LOAD_METHOD);
STAT_INC(LOAD_METHOD, hit);

9
Python/specialize.c
View File

@ -986,7 +986,7 @@ _Py_Specialize_LoadMethod(PyObject *owner, _Py_CODEUNIT *instr, PyObject *name)
}
}
}
if (dictkind == MANAGED_VALUES || dictkind == MANAGED_DICT || dictkind == OFFSET_DICT) {
if (dictkind == MANAGED_VALUES || dictkind == OFFSET_DICT) {
Py_ssize_t index = _PyDictKeys_StringLookup(keys, name);
if (index != DKIX_EMPTY) {
SPECIALIZATION_FAIL(LOAD_METHOD, SPEC_FAIL_LOAD_METHOD_IS_ATTR);
@ -1007,17 +1007,14 @@ _Py_Specialize_LoadMethod(PyObject *owner, _Py_CODEUNIT *instr, PyObject *name)
_Py_SET_OPCODE(*instr, LOAD_METHOD_WITH_VALUES);
break;
case MANAGED_DICT:
*(int16_t *)&cache->dict_offset = (int16_t)MANAGED_DICT_OFFSET;
_Py_SET_OPCODE(*instr, LOAD_METHOD_WITH_DICT);
break;
SPECIALIZATION_FAIL(LOAD_METHOD, SPEC_FAIL_LOAD_METHOD_HAS_MANAGED_DICT);
goto fail;
case OFFSET_DICT:
assert(owner_cls->tp_dictoffset > 0 && owner_cls->tp_dictoffset <= INT16_MAX);
cache->dict_offset = (uint16_t)owner_cls->tp_dictoffset;
_Py_SET_OPCODE(*instr, LOAD_METHOD_WITH_DICT);
break;
case LAZY_DICT:
assert(owner_cls->tp_dictoffset > 0 && owner_cls->tp_dictoffset <= INT16_MAX);
cache->dict_offset = (uint16_t)owner_cls->tp_dictoffset;
_Py_SET_OPCODE(*instr, LOAD_METHOD_LAZY_DICT);
break;
}