[Python-checkins] Shrink the LOAD_METHOD cache by one codeunit. (#93537)
markshannon
webhook-mailer at python.org
Tue Jun 7 05:29:01 EDT 2022
https://github.com/python/cpython/commit/f012df706cf3a9e63625b8166fe3f419855e9a94
commit: f012df706cf3a9e63625b8166fe3f419855e9a94
branch: main
author: Mark Shannon <mark at hotpy.org>
committer: markshannon <mark at hotpy.org>
date: 2022-06-07T10:28:53+01:00
summary:
Shrink the LOAD_METHOD cache by one codeunit. (#93537)
files:
A Misc/NEWS.d/next/Core and Builtins/2022-06-06-14-28-24.gh-issue-93533.lnC0CC.rst
M Include/internal/pycore_code.h
M Include/internal/pycore_opcode.h
M Lib/importlib/_bootstrap_external.py
M Lib/opcode.py
M Lib/test/test_dis.py
M Python/ceval.c
M Python/specialize.c
diff --git a/Include/internal/pycore_code.h b/Include/internal/pycore_code.h
index 9d33ed71e7890..c181543722f6e 100644
--- a/Include/internal/pycore_code.h
+++ b/Include/internal/pycore_code.h
@@ -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;
diff --git a/Include/internal/pycore_opcode.h b/Include/internal/pycore_opcode.h
index e5d948dd696a2..e254537da763a 100644
--- a/Include/internal/pycore_opcode.h
+++ b/Include/internal/pycore_opcode.h
@@ -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,
};
diff --git a/Lib/importlib/_bootstrap_external.py b/Lib/importlib/_bootstrap_external.py
index 894848a15d97d..1b6654202f3d7 100644
--- a/Lib/importlib/_bootstrap_external.py
+++ b/Lib/importlib/_bootstrap_external.py
@@ -407,6 +407,7 @@ def _write_atomic(path, data, mode=0o666):
# 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 @@ def _write_atomic(path, data, mode=0o666):
# 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
diff --git a/Lib/opcode.py b/Lib/opcode.py
index 5cbb5c57521ae..0996cc7eb0f6c 100644
--- a/Lib/opcode.py
+++ b/Lib/opcode.py
@@ -383,7 +383,6 @@ def jabs_op(name, op):
"LOAD_METHOD": {
"counter": 1,
"type_version": 2,
- "dict_offset": 1,
"keys_version": 2,
"descr": 4,
},
diff --git a/Lib/test/test_dis.py b/Lib/test/test_dis.py
index a4f7f84995bf5..a94cd6432e123 100644
--- a/Lib/test/test_dis.py
+++ b/Lib/test/test_dis.py
@@ -1047,7 +1047,7 @@ def test_show_caches(self):
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):
diff --git a/Misc/NEWS.d/next/Core and Builtins/2022-06-06-14-28-24.gh-issue-93533.lnC0CC.rst b/Misc/NEWS.d/next/Core and Builtins/2022-06-06-14-28-24.gh-issue-93533.lnC0CC.rst
new file mode 100644
index 0000000000000..2d8ac7068af67
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2022-06-06-14-28-24.gh-issue-93533.lnC0CC.rst
@@ -0,0 +1 @@
+Reduce the size of the inline cache for ``LOAD_METHOD`` by 2 bytes.
diff --git a/Python/ceval.c b/Python/ceval.c
index ec86c70673ca9..d1480ac190ea4 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -4581,12 +4581,9 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
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 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
_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);
diff --git a/Python/specialize.c b/Python/specialize.c
index 4d30a2aea5f3b..1df281a19a41e 100644
--- a/Python/specialize.c
+++ b/Python/specialize.c
@@ -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;
}
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