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bpo-36904: Optimize _PyStack_UnpackDict (GH-14517)

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This commit is contained in:
Jeroen Demeyer 2019-07-02 11:49:40 +02:00 committed by Inada Naoki
parent 5bbbc733e6
commit d4efd917ac
2 changed files with 86 additions and 82 deletions
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18
Include/cpython/abstract.h
View File

@ -26,24 +26,6 @@ PyAPI_FUNC(PyObject *) _PyStack_AsDict(
PyObject *const *values,
PyObject *kwnames);
/* Convert (args, nargs, kwargs: dict) into a (stack, nargs, kwnames: tuple).
Return 0 on success, raise an exception and return -1 on error.
Write the new stack into *p_stack. If *p_stack is differen than args, it
must be released by PyMem_Free().
The stack uses borrowed references.
The type of keyword keys is not checked, these checks should be done
later (ex: _PyArg_ParseStackAndKeywords). */
PyAPI_FUNC(int) _PyStack_UnpackDict(
PyObject *const *args,
Py_ssize_t nargs,
PyObject *kwargs,
PyObject *const **p_stack,
PyObject **p_kwnames);
/* Suggested size (number of positional arguments) for arrays of PyObject*
allocated on a C stack to avoid allocating memory on the heap memory. Such
array is used to pass positional arguments to call functions of the

150
Objects/call.c
View File

@ -8,6 +8,14 @@
static PyObject *
cfunction_call_varargs(PyObject *func, PyObject *args, PyObject *kwargs);
static PyObject *const *
_PyStack_UnpackDict(PyObject *const *args, Py_ssize_t nargs, PyObject *kwargs,
PyObject **p_kwnames);
static void
_PyStack_UnpackDict_Free(PyObject *const *stack, Py_ssize_t nargs,
PyObject *kwnames);
static PyObject *
null_error(void)
@ -100,24 +108,19 @@ _PyObject_FastCallDict(PyObject *callable, PyObject *const *args,
}
PyObject *res;
if (kwargs == NULL) {
if (kwargs == NULL || PyDict_GET_SIZE(kwargs) == 0) {
res = func(callable, args, nargsf, NULL);
}
else {
PyObject *kwnames;
PyObject *const *newargs;
if (_PyStack_UnpackDict(args, nargs, kwargs, &newargs, &kwnames) < 0) {
newargs = _PyStack_UnpackDict(args, nargs, kwargs, &kwnames);
if (newargs == NULL) {
return NULL;
}
res = func(callable, newargs, nargs, kwnames);
if (kwnames != NULL) {
Py_ssize_t i, n = PyTuple_GET_SIZE(kwnames) + nargs;
for (i = 0; i < n; i++) {
Py_DECREF(newargs[i]);
}
PyMem_Free((PyObject **)newargs);
Py_DECREF(kwnames);
}
res = func(callable, newargs,
nargs | PY_VECTORCALL_ARGUMENTS_OFFSET, kwnames);
_PyStack_UnpackDict_Free(newargs, nargs, kwnames);
}
return _Py_CheckFunctionResult(callable, res, NULL);
}
@ -196,24 +199,23 @@ PyVectorcall_Call(PyObject *callable, PyObject *tuple, PyObject *kwargs)
return NULL;
}
/* Convert arguments & call */
PyObject *const *args;
Py_ssize_t nargs = PyTuple_GET_SIZE(tuple);
PyObject *kwnames;
if (_PyStack_UnpackDict(_PyTuple_ITEMS(tuple), nargs,
kwargs, &args, &kwnames) < 0) {
return NULL;
}
PyObject *result = func(callable, args, nargs, kwnames);
if (kwnames != NULL) {
Py_ssize_t i, n = PyTuple_GET_SIZE(kwnames) + nargs;
for (i = 0; i < n; i++) {
Py_DECREF(args[i]);
}
PyMem_Free((PyObject **)args);
Py_DECREF(kwnames);
/* Fast path for no keywords */
if (kwargs == NULL || PyDict_GET_SIZE(kwargs) == 0) {
return func(callable, _PyTuple_ITEMS(tuple), nargs, NULL);
}
/* Convert arguments & call */
PyObject *const *args;
PyObject *kwnames;
args = _PyStack_UnpackDict(_PyTuple_ITEMS(tuple), nargs, kwargs, &kwnames);
if (args == NULL) {
return NULL;
}
PyObject *result = func(callable, args,
nargs | PY_VECTORCALL_ARGUMENTS_OFFSET, kwnames);
_PyStack_UnpackDict_Free(args, nargs, kwnames);
return result;
}
@ -455,23 +457,22 @@ _PyMethodDef_RawFastCallDict(PyMethodDef *method, PyObject *self,
case METH_FASTCALL | METH_KEYWORDS:
{
PyObject *const *stack;
PyObject *kwnames;
_PyCFunctionFastWithKeywords fastmeth = (_PyCFunctionFastWithKeywords)(void(*)(void))meth;
if (_PyStack_UnpackDict(args, nargs, kwargs, &stack, &kwnames) < 0) {
goto exit;
/* Fast path for no keywords */
if (kwargs == NULL || PyDict_GET_SIZE(kwargs) == 0) {
result = (*fastmeth) (self, args, nargs, NULL);
break;
}
PyObject *const *stack;
PyObject *kwnames;
stack = _PyStack_UnpackDict(args, nargs, kwargs, &kwnames);
if (stack == NULL) {
goto exit;
}
result = (*fastmeth) (self, stack, nargs, kwnames);
if (kwnames != NULL) {
Py_ssize_t i, n = nargs + PyTuple_GET_SIZE(kwnames);
for (i = 0; i < n; i++) {
Py_DECREF(stack[i]);
}
PyMem_Free((PyObject **)stack);
Py_DECREF(kwnames);
}
_PyStack_UnpackDict_Free(stack, nargs, kwnames);
break;
}
@ -1206,53 +1207,63 @@ _PyStack_AsDict(PyObject *const *values, PyObject *kwnames)
}
int
/* Convert (args, nargs, kwargs: dict) into a (stack, nargs, kwnames: tuple).
Allocate a new argument vector and keyword names tuple. Return the argument
vector; return NULL with exception set on error. Return the keyword names
tuple in *p_kwnames.
The newly allocated argument vector supports PY_VECTORCALL_ARGUMENTS_OFFSET.
When done, you must call _PyStack_UnpackDict_Free(stack, nargs, kwnames)
The type of keyword keys is not checked, these checks should be done
later (ex: _PyArg_ParseStackAndKeywords). */
static PyObject *const *
_PyStack_UnpackDict(PyObject *const *args, Py_ssize_t nargs, PyObject *kwargs,
PyObject *const **p_stack, PyObject **p_kwnames)
PyObject **p_kwnames)
{
PyObject **stack, **kwstack;
Py_ssize_t nkwargs;
Py_ssize_t pos, i;
PyObject *key, *value;
PyObject *kwnames;
assert(nargs >= 0);
assert(kwargs == NULL || PyDict_CheckExact(kwargs));
assert(kwargs != NULL);
assert(PyDict_Check(kwargs));
if (kwargs == NULL || (nkwargs = PyDict_GET_SIZE(kwargs)) == 0) {
*p_stack = args;
*p_kwnames = NULL;
return 0;
}
if ((size_t)nargs > PY_SSIZE_T_MAX / sizeof(stack[0]) - (size_t)nkwargs) {
Py_ssize_t nkwargs = PyDict_GET_SIZE(kwargs);
/* Check for overflow in the PyMem_Malloc() call below. The subtraction
* in this check cannot overflow: both maxnargs and nkwargs are
* non-negative signed integers, so their difference fits in the type. */
Py_ssize_t maxnargs = PY_SSIZE_T_MAX / sizeof(args[0]) - 1;
if (nargs > maxnargs - nkwargs) {
PyErr_NoMemory();
return -1;
return NULL;
}
stack = PyMem_Malloc((nargs + nkwargs) * sizeof(stack[0]));
/* Add 1 to support PY_VECTORCALL_ARGUMENTS_OFFSET */
PyObject **stack = PyMem_Malloc((1 + nargs + nkwargs) * sizeof(args[0]));
if (stack == NULL) {
PyErr_NoMemory();
return -1;
return NULL;
}
kwnames = PyTuple_New(nkwargs);
PyObject *kwnames = PyTuple_New(nkwargs);
if (kwnames == NULL) {
PyMem_Free(stack);
return -1;
return NULL;
}
stack++; /* For PY_VECTORCALL_ARGUMENTS_OFFSET */
/* Copy positional arguments */
for (i = 0; i < nargs; i++) {
for (Py_ssize_t i = 0; i < nargs; i++) {
Py_INCREF(args[i]);
stack[i] = args[i];
}
kwstack = stack + nargs;
pos = i = 0;
PyObject **kwstack = stack + nargs;
/* This loop doesn't support lookup function mutating the dictionary
to change its size. It's a deliberate choice for speed, this function is
called in the performance critical hot code. */
Py_ssize_t pos = 0, i = 0;
PyObject *key, *value;
while (PyDict_Next(kwargs, &pos, &key, &value)) {
Py_INCREF(key);
Py_INCREF(value);
@ -1261,7 +1272,18 @@ _PyStack_UnpackDict(PyObject *const *args, Py_ssize_t nargs, PyObject *kwargs,
i++;
}
*p_stack = stack;
*p_kwnames = kwnames;
return 0;
return stack;
}
static void
_PyStack_UnpackDict_Free(PyObject *const *stack, Py_ssize_t nargs,
PyObject *kwnames)
{
Py_ssize_t n = PyTuple_GET_SIZE(kwnames) + nargs;
for (Py_ssize_t i = 0; i < n; i++) {
Py_DECREF(stack[i]);
}
PyMem_Free((PyObject **)stack - 1);
Py_DECREF(kwnames);
}