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[3.13] gh-128133: use relaxed atomics for hash of bytes (GH-128412) #130022

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Merged
merged 1 commit into from
Feb 12, 2025
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[3.13] gh-128133: use relaxed atomics for hash of bytes (GH-128412) #130022

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70 changes: 39 additions & 31 deletions Objects/bytesobject.c
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Original file line number Diff line number Diff line change
Expand Up @@ -51,6 +51,33 @@ static inline PyObject* bytes_get_empty(void)
}


static inline void
set_ob_shash(PyBytesObject *a, Py_hash_t hash)
{
_Py_COMP_DIAG_PUSH
_Py_COMP_DIAG_IGNORE_DEPR_DECLS
#ifdef Py_GIL_DISABLED
_Py_atomic_store_ssize_relaxed(&a->ob_shash, hash);
#else
a->ob_shash = hash;
#endif
_Py_COMP_DIAG_POP
}

static inline Py_hash_t
get_ob_shash(PyBytesObject *a)
{
_Py_COMP_DIAG_PUSH
_Py_COMP_DIAG_IGNORE_DEPR_DECLS
#ifdef Py_GIL_DISABLED
return _Py_atomic_load_ssize_relaxed(&a->ob_shash);
#else
return a->ob_shash;
#endif
_Py_COMP_DIAG_POP
}


/*
For PyBytes_FromString(), the parameter `str' points to a null-terminated
string containing exactly `size' bytes.
Expand Down Expand Up @@ -98,10 +125,7 @@ _PyBytes_FromSize(Py_ssize_t size, int use_calloc)
return PyErr_NoMemory();
}
_PyObject_InitVar((PyVarObject*)op, &PyBytes_Type, size);
_Py_COMP_DIAG_PUSH
_Py_COMP_DIAG_IGNORE_DEPR_DECLS
op->ob_shash = -1;
_Py_COMP_DIAG_POP
set_ob_shash(op, -1);
if (!use_calloc) {
op->ob_sval[size] = '\0';
}
Expand Down Expand Up @@ -165,10 +189,7 @@ PyBytes_FromString(const char *str)
return PyErr_NoMemory();
}
_PyObject_InitVar((PyVarObject*)op, &PyBytes_Type, size);
_Py_COMP_DIAG_PUSH
_Py_COMP_DIAG_IGNORE_DEPR_DECLS
op->ob_shash = -1;
_Py_COMP_DIAG_POP
set_ob_shash(op, -1);
memcpy(op->ob_sval, str, size+1);
return (PyObject *) op;
}
Expand Down Expand Up @@ -1475,10 +1496,7 @@ bytes_repeat(PyBytesObject *a, Py_ssize_t n)
return PyErr_NoMemory();
}
_PyObject_InitVar((PyVarObject*)op, &PyBytes_Type, size);
_Py_COMP_DIAG_PUSH
_Py_COMP_DIAG_IGNORE_DEPR_DECLS
op->ob_shash = -1;
_Py_COMP_DIAG_POP
set_ob_shash(op, -1);
op->ob_sval[size] = '\0';

_PyBytes_Repeat(op->ob_sval, size, a->ob_sval, Py_SIZE(a));
Expand Down Expand Up @@ -1583,14 +1601,13 @@ bytes_richcompare(PyBytesObject *a, PyBytesObject *b, int op)
static Py_hash_t
bytes_hash(PyBytesObject *a)
{
_Py_COMP_DIAG_PUSH
_Py_COMP_DIAG_IGNORE_DEPR_DECLS
if (a->ob_shash == -1) {
Py_hash_t hash = get_ob_shash(a);
if (hash == -1) {
/* Can't fail */
a->ob_shash = _Py_HashBytes(a->ob_sval, Py_SIZE(a));
hash = _Py_HashBytes(a->ob_sval, Py_SIZE(a));
set_ob_shash(a, hash);
}
return a->ob_shash;
_Py_COMP_DIAG_POP
return hash;
}

static PyObject*
Expand Down Expand Up @@ -2970,10 +2987,7 @@ bytes_alloc(PyTypeObject *self, Py_ssize_t nitems)
if (obj == NULL) {
return NULL;
}
_Py_COMP_DIAG_PUSH
_Py_COMP_DIAG_IGNORE_DEPR_DECLS
obj->ob_shash = -1;
_Py_COMP_DIAG_POP
set_ob_shash(obj, -1);
return (PyObject*)obj;
}

Expand All @@ -2990,11 +3004,8 @@ bytes_subtype_new(PyTypeObject *type, PyObject *tmp)
if (pnew != NULL) {
memcpy(PyBytes_AS_STRING(pnew),
PyBytes_AS_STRING(tmp), n+1);
_Py_COMP_DIAG_PUSH
_Py_COMP_DIAG_IGNORE_DEPR_DECLS
((PyBytesObject *)pnew)->ob_shash =
((PyBytesObject *)tmp)->ob_shash;
_Py_COMP_DIAG_POP
set_ob_shash((PyBytesObject *)pnew,
get_ob_shash((PyBytesObject *)tmp));
}
return pnew;
}
Expand Down Expand Up @@ -3186,10 +3197,7 @@ _PyBytes_Resize(PyObject **pv, Py_ssize_t newsize)
sv = (PyBytesObject *) *pv;
Py_SET_SIZE(sv, newsize);
sv->ob_sval[newsize] = '\0';
_Py_COMP_DIAG_PUSH
_Py_COMP_DIAG_IGNORE_DEPR_DECLS
sv->ob_shash = -1; /* invalidate cached hash value */
_Py_COMP_DIAG_POP
set_ob_shash(sv, -1); /* invalidate cached hash value */
return 0;
}

Expand Down
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