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gh-95756: Lazily created cached co_* attrs (GH-97791)
1 parent f871e9a commit b399115

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5 files changed

+82
-14
lines changed

5 files changed

+82
-14
lines changed

‎Include/cpython/code.h

+8-1
Original file line numberDiff line numberDiff line change
@@ -32,6 +32,13 @@ typedef uint16_t _Py_CODEUNIT;
3232
#define _Py_SET_OPCODE(word, opcode) \
3333
do { ((unsigned char *)&(word))[0] = (opcode); } while (0)
3434

35+
typedef struct {
36+
PyObject *_co_code;
37+
PyObject *_co_varnames;
38+
PyObject *_co_cellvars;
39+
PyObject *_co_freevars;
40+
} _PyCoCached;
41+
3542
// To avoid repeating ourselves in deepfreeze.py, all PyCodeObject members are
3643
// defined in this macro:
3744
#define _PyCode_DEF(SIZE) { \
@@ -90,7 +97,7 @@ typedef uint16_t _Py_CODEUNIT;
9097
PyObject *co_qualname; /* unicode (qualname, for reference) */ \
9198
PyObject *co_linetable; /* bytes object that holds location info */ \
9299
PyObject *co_weakreflist; /* to support weakrefs to code objects */ \
93-
PyObject *_co_code; /* cached co_code object/attribute */ \
100+
_PyCoCached *_co_cached; /* cached co_* attributes */ \
94101
int _co_firsttraceable; /* index of first traceable instruction */ \
95102
char *_co_linearray; /* array of line offsets */ \
96103
/* Scratch space for extra data relating to the code object. \

‎Misc/NEWS.d/next/C API/2022-10-03-20-33-24.gh-issue-95756.SSmXlG.rst

+1
Original file line numberDiff line numberDiff line change
@@ -0,0 +1 @@
1+
Lazily create and cache ``co_`` attributes for better performance for code getters.

‎Objects/codeobject.c

+67-10
Original file line numberDiff line numberDiff line change
@@ -150,7 +150,22 @@ validate_and_copy_tuple(PyObject *tup)
150150
return newtuple;
151151
}
152152

153+
static int
154+
init_co_cached(PyCodeObject *self) {
155+
if (self->_co_cached == NULL) {
156+
self->_co_cached = PyMem_New(_PyCoCached, 1);
157+
if (self->_co_cached == NULL) {
158+
PyErr_NoMemory();
159+
return -1;
160+
}
161+
self->_co_cached->_co_code = NULL;
162+
self->_co_cached->_co_cellvars = NULL;
163+
self->_co_cached->_co_freevars = NULL;
164+
self->_co_cached->_co_varnames = NULL;
165+
}
166+
return 0;
153167

168+
}
154169
/******************
155170
* _PyCode_New()
156171
******************/
@@ -336,7 +351,7 @@ init_code(PyCodeObject *co, struct _PyCodeConstructor *con)
336351
/* not set */
337352
co->co_weakreflist = NULL;
338353
co->co_extra = NULL;
339-
co->_co_code = NULL;
354+
co->_co_cached = NULL;
340355

341356
co->co_warmup = QUICKENING_INITIAL_WARMUP_VALUE;
342357
co->_co_linearray_entry_size = 0;
@@ -1384,10 +1399,31 @@ _PyCode_SetExtra(PyObject *code, Py_ssize_t index, void *extra)
13841399
* other PyCodeObject accessor functions
13851400
******************/
13861401

1402+
static PyObject *
1403+
get_cached_locals(PyCodeObject *co, PyObject **cached_field,
1404+
_PyLocals_Kind kind, int num)
1405+
{
1406+
assert(cached_field != NULL);
1407+
assert(co->_co_cached != NULL);
1408+
if (*cached_field != NULL) {
1409+
return Py_NewRef(*cached_field);
1410+
}
1411+
assert(*cached_field == NULL);
1412+
PyObject *varnames = get_localsplus_names(co, kind, num);
1413+
if (varnames == NULL) {
1414+
return NULL;
1415+
}
1416+
*cached_field = Py_NewRef(varnames);
1417+
return varnames;
1418+
}
1419+
13871420
PyObject *
13881421
_PyCode_GetVarnames(PyCodeObject *co)
13891422
{
1390-
return get_localsplus_names(co, CO_FAST_LOCAL, co->co_nlocals);
1423+
if (init_co_cached(co)) {
1424+
return NULL;
1425+
}
1426+
return get_cached_locals(co, &co->_co_cached->_co_varnames, CO_FAST_LOCAL, co->co_nlocals);
13911427
}
13921428

13931429
PyObject *
@@ -1399,7 +1435,10 @@ PyCode_GetVarnames(PyCodeObject *code)
13991435
PyObject *
14001436
_PyCode_GetCellvars(PyCodeObject *co)
14011437
{
1402-
return get_localsplus_names(co, CO_FAST_CELL, co->co_ncellvars);
1438+
if (init_co_cached(co)) {
1439+
return NULL;
1440+
}
1441+
return get_cached_locals(co, &co->_co_cached->_co_cellvars, CO_FAST_CELL, co->co_ncellvars);
14031442
}
14041443

14051444
PyObject *
@@ -1411,7 +1450,10 @@ PyCode_GetCellvars(PyCodeObject *code)
14111450
PyObject *
14121451
_PyCode_GetFreevars(PyCodeObject *co)
14131452
{
1414-
return get_localsplus_names(co, CO_FAST_FREE, co->co_nfreevars);
1453+
if (init_co_cached(co)) {
1454+
return NULL;
1455+
}
1456+
return get_cached_locals(co, &co->_co_cached->_co_freevars, CO_FAST_FREE, co->co_nfreevars);
14151457
}
14161458

14171459
PyObject *
@@ -1437,17 +1479,20 @@ deopt_code(_Py_CODEUNIT *instructions, Py_ssize_t len)
14371479
PyObject *
14381480
_PyCode_GetCode(PyCodeObject *co)
14391481
{
1440-
if (co->_co_code != NULL) {
1441-
return Py_NewRef(co->_co_code);
1482+
if (init_co_cached(co)) {
1483+
return NULL;
1484+
}
1485+
if (co->_co_cached->_co_code != NULL) {
1486+
return Py_NewRef(co->_co_cached->_co_code);
14421487
}
14431488
PyObject *code = PyBytes_FromStringAndSize((const char *)_PyCode_CODE(co),
14441489
_PyCode_NBYTES(co));
14451490
if (code == NULL) {
14461491
return NULL;
14471492
}
14481493
deopt_code((_Py_CODEUNIT *)PyBytes_AS_STRING(code), Py_SIZE(co));
1449-
assert(co->_co_code == NULL);
1450-
co->_co_code = Py_NewRef(code);
1494+
assert(co->_co_cached->_co_code == NULL);
1495+
co->_co_cached->_co_code = Py_NewRef(code);
14511496
return code;
14521497
}
14531498

@@ -1606,7 +1651,13 @@ code_dealloc(PyCodeObject *co)
16061651
Py_XDECREF(co->co_qualname);
16071652
Py_XDECREF(co->co_linetable);
16081653
Py_XDECREF(co->co_exceptiontable);
1609-
Py_XDECREF(co->_co_code);
1654+
if (co->_co_cached != NULL) {
1655+
Py_XDECREF(co->_co_cached->_co_code);
1656+
Py_XDECREF(co->_co_cached->_co_cellvars);
1657+
Py_XDECREF(co->_co_cached->_co_freevars);
1658+
Py_XDECREF(co->_co_cached->_co_varnames);
1659+
PyMem_Free(co->_co_cached);
1660+
}
16101661
if (co->co_weakreflist != NULL) {
16111662
PyObject_ClearWeakRefs((PyObject*)co);
16121663
}
@@ -2181,7 +2232,13 @@ _PyStaticCode_Dealloc(PyCodeObject *co)
21812232
deopt_code(_PyCode_CODE(co), Py_SIZE(co));
21822233
co->co_warmup = QUICKENING_INITIAL_WARMUP_VALUE;
21832234
PyMem_Free(co->co_extra);
2184-
Py_CLEAR(co->_co_code);
2235+
if (co->_co_cached != NULL) {
2236+
Py_CLEAR(co->_co_cached->_co_code);
2237+
Py_CLEAR(co->_co_cached->_co_cellvars);
2238+
Py_CLEAR(co->_co_cached->_co_freevars);
2239+
Py_CLEAR(co->_co_cached->_co_varnames);
2240+
PyMem_Free(co->_co_cached);
2241+
}
21852242
co->co_extra = NULL;
21862243
if (co->co_weakreflist != NULL) {
21872244
PyObject_ClearWeakRefs((PyObject *)co);

‎Objects/frameobject.c

+5-2
Original file line numberDiff line numberDiff line change
@@ -645,9 +645,12 @@ add_load_fast_null_checks(PyCodeObject *co)
645645
}
646646
i += _PyOpcode_Caches[_PyOpcode_Deopt[opcode]];
647647
}
648-
if (changed) {
648+
if (changed && co->_co_cached != NULL) {
649649
// invalidate cached co_code object
650-
Py_CLEAR(co->_co_code);
650+
Py_CLEAR(co->_co_cached->_co_code);
651+
Py_CLEAR(co->_co_cached->_co_cellvars);
652+
Py_CLEAR(co->_co_cached->_co_freevars);
653+
Py_CLEAR(co->_co_cached->_co_varnames);
651654
}
652655
}
653656

‎Tools/scripts/deepfreeze.py

+1-1
Original file line numberDiff line numberDiff line change
@@ -276,7 +276,7 @@ def generate_code(self, name: str, code: types.CodeType) -> str:
276276
self.write(f".co_name = {co_name},")
277277
self.write(f".co_qualname = {co_qualname},")
278278
self.write(f".co_linetable = {co_linetable},")
279-
self.write(f"._co_code = NULL,")
279+
self.write(f"._co_cached = NULL,")
280280
self.write("._co_linearray = NULL,")
281281
self.write(f".co_code_adaptive = {co_code_adaptive},")
282282
for i, op in enumerate(code.co_code[::2]):

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