cpython/Python/optimizer.c

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#include "Python.h"
#include "opcode.h"
#include "pycore_interp.h"
#include "pycore_opcode.h"
#include "pycore_pystate.h"
#include "cpython/optimizer.h"
#include <stdbool.h>
#include <stdint.h>
#include <stddef.h>
/* Returns the index of the next space, or -1 if there is no
* more space. Doesn't set an exception. */
static int32_t
get_next_free_in_executor_array(PyCodeObject *code)
{
_PyExecutorArray *old = code->co_executors;
int size = 0;
int capacity = 0;
if (old != NULL) {
size = old->size;
capacity = old->capacity;
if (capacity >= 256) {
return -1;
}
}
assert(size <= capacity);
if (size == capacity) {
/* Array is full. Grow array */
int new_capacity = capacity ? capacity * 2 : 4;
_PyExecutorArray *new = PyMem_Realloc(
old,
offsetof(_PyExecutorArray, executors) +
new_capacity * sizeof(_PyExecutorObject *));
if (new == NULL) {
return -1;
}
new->capacity = new_capacity;
new->size = size;
code->co_executors = new;
}
assert(size < code->co_executors->capacity);
code->co_executors->size++;
return size;
}
static void
insert_executor(PyCodeObject *code, _Py_CODEUNIT *instr, int index, _PyExecutorObject *executor)
{
if (instr->op.code == ENTER_EXECUTOR) {
assert(index == instr->op.arg);
_PyExecutorObject *old = code->co_executors->executors[index];
executor->vm_data.opcode = old->vm_data.opcode;
executor->vm_data.oparg = old->vm_data.oparg;
old->vm_data.opcode = 0;
Py_INCREF(executor);
code->co_executors->executors[index] = executor;
Py_DECREF(old);
}
else {
Py_INCREF(executor);
executor->vm_data.opcode = instr->op.code;
executor->vm_data.oparg = instr->op.arg;
code->co_executors->executors[index] = executor;
assert(index < 256);
instr->op.code = ENTER_EXECUTOR;
instr->op.arg = index;
}
return;
}
static int
get_executor_index(PyCodeObject *code, _Py_CODEUNIT *instr)
{
if (instr->op.code == ENTER_EXECUTOR) {
return instr->op.arg;
}
else {
return get_next_free_in_executor_array(code);
}
}
int
PyUnstable_Replace_Executor(PyCodeObject *code, _Py_CODEUNIT *instr, _PyExecutorObject *new)
{
if (instr->op.code != ENTER_EXECUTOR) {
PyErr_Format(PyExc_ValueError, "No executor to replace");
return -1;
}
int index = get_executor_index(code, instr);
assert(index >= 0);
insert_executor(code, instr, index, new);
return 0;
}
static _PyExecutorObject *
error_optimize(
_PyOptimizerObject* self,
PyCodeObject *code,
_Py_CODEUNIT *instr)
{
PyErr_Format(PyExc_SystemError, "Should never call error_optimize");
return NULL;
}
static PyTypeObject DefaultOptimizer_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
.tp_name = "noop_optimizer",
.tp_basicsize = sizeof(_PyOptimizerObject),
.tp_itemsize = 0,
.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_DISALLOW_INSTANTIATION,
};
_PyOptimizerObject _PyOptimizer_Default = {
PyObject_HEAD_INIT(&DefaultOptimizer_Type)
.optimize = error_optimize,
.resume_threshold = UINT16_MAX,
.backedge_threshold = UINT16_MAX,
};
_PyOptimizerObject *
PyUnstable_GetOptimizer(void)
{
PyInterpreterState *interp = PyInterpreterState_Get();
if (interp->optimizer == &_PyOptimizer_Default) {
return NULL;
}
Py_INCREF(interp->optimizer);
return interp->optimizer;
}
void
PyUnstable_SetOptimizer(_PyOptimizerObject *optimizer)
{
PyInterpreterState *interp = PyInterpreterState_Get();
if (optimizer == NULL) {
optimizer = &_PyOptimizer_Default;
}
_PyOptimizerObject *old = interp->optimizer;
Py_INCREF(optimizer);
interp->optimizer = optimizer;
interp->optimizer_backedge_threshold = optimizer->backedge_threshold;
interp->optimizer_resume_threshold = optimizer->resume_threshold;
Py_DECREF(old);
}
_PyInterpreterFrame *
_PyOptimizer_BackEdge(_PyInterpreterFrame *frame, _Py_CODEUNIT *src, _Py_CODEUNIT *dest, PyObject **stack_pointer)
{
PyInterpreterState *interp = PyInterpreterState_Get();
int index = get_executor_index(frame->f_code, src);
if (index < 0) {
_PyFrame_SetStackPointer(frame, stack_pointer);
return frame;
}
_PyOptimizerObject *opt = interp->optimizer;
_PyExecutorObject *executor = opt->optimize(opt, frame->f_code, dest);
if (executor == NULL) {
return NULL;
}
insert_executor(frame->f_code, src, index, executor);
return executor->execute(executor, frame, stack_pointer);
}
/** Test support **/
typedef struct {
_PyOptimizerObject base;
int64_t count;
} _PyCounterOptimizerObject;
typedef struct {
_PyExecutorObject executor;
_PyCounterOptimizerObject *optimizer;
_Py_CODEUNIT *next_instr;
} _PyCounterExecutorObject;
static void
counter_dealloc(_PyCounterExecutorObject *self) {
Py_DECREF(self->optimizer);
PyObject_Free(self);
}
static PyTypeObject CounterExecutor_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
.tp_name = "counting_executor",
.tp_basicsize = sizeof(_PyCounterExecutorObject),
.tp_itemsize = 0,
.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_DISALLOW_INSTANTIATION,
.tp_dealloc = (destructor)counter_dealloc,
};
static _PyInterpreterFrame *
counter_execute(_PyExecutorObject *self, _PyInterpreterFrame *frame, PyObject **stack_pointer)
{
((_PyCounterExecutorObject *)self)->optimizer->count++;
_PyFrame_SetStackPointer(frame, stack_pointer);
frame->prev_instr = ((_PyCounterExecutorObject *)self)->next_instr - 1;
Py_DECREF(self);
return frame;
}
static _PyExecutorObject *
counter_optimize(
_PyOptimizerObject* self,
PyCodeObject *code,
_Py_CODEUNIT *instr)
{
_PyCounterExecutorObject *executor = (_PyCounterExecutorObject *)_PyObject_New(&CounterExecutor_Type);
if (executor == NULL) {
return NULL;
}
executor->executor.execute = counter_execute;
Py_INCREF(self);
executor->optimizer = (_PyCounterOptimizerObject *)self;
executor->next_instr = instr;
return (_PyExecutorObject *)executor;
}
static PyObject *
counter_get_counter(PyObject *self, PyObject *args)
{
return PyLong_FromLongLong(((_PyCounterOptimizerObject *)self)->count);
}
static PyMethodDef counter_methods[] = {
{ "get_count", counter_get_counter, METH_NOARGS, NULL },
{ NULL, NULL },
};
static PyTypeObject CounterOptimizer_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
.tp_name = "Counter optimizer",
.tp_basicsize = sizeof(_PyCounterOptimizerObject),
.tp_itemsize = 0,
.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_DISALLOW_INSTANTIATION,
.tp_methods = counter_methods,
};
PyObject *
PyUnstable_Optimizer_NewCounter(void)
{
_PyCounterOptimizerObject *opt = (_PyCounterOptimizerObject *)_PyObject_New(&CounterOptimizer_Type);
if (opt == NULL) {
return NULL;
}
opt->base.optimize = counter_optimize;
opt->base.resume_threshold = UINT16_MAX;
opt->base.backedge_threshold = 0;
opt->count = 0;
return (PyObject *)opt;
}