#include "Python.h"

#include "opcode.h"

#include "pycore_interp.h"

#include "pycore_opcode.h"

#include "opcode_metadata.h"

#include "pycore_pystate.h" // _PyInterpreterState_GET()

#include "pycore_uops.h"

#include "cpython/optimizer.h"

#include <stdbool.h>

#include <stdint.h>

#include <stddef.h>

static bool

has_space_for_executor(PyCodeObject *code, _Py_CODEUNIT *instr)

{

if (instr->op.code == ENTER_EXECUTOR) {

return true;

}

if (code->co_executors == NULL) {

return true;

}

return code->co_executors->size < 256;

}

static int32_t

get_index_for_executor(PyCodeObject *code, _Py_CODEUNIT *instr)

{

if (instr->op.code == ENTER_EXECUTOR) {

return instr->op.arg;

}

_PyExecutorArray *old = code->co_executors;

int size = 0;

int capacity = 0;

if (old != NULL) {

size = old->size;

capacity = old->capacity;

assert(size < 256);

}

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);

return size;

}

static void

insert_executor(PyCodeObject *code, _Py_CODEUNIT *instr, int index, _PyExecutorObject *executor)

{

Py_INCREF(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;

code->co_executors->executors[index] = executor;

Py_DECREF(old);

}

else {

assert(code->co_executors->size == index);

assert(code->co_executors->capacity > index);

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;

code->co_executors->size++;

}

return;

}

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 = instr->op.arg;

assert(index >= 0);

insert_executor(code, instr, index, new);

return 0;

}

static int

error_optimize(

_PyOptimizerObject* self,

PyCodeObject *code,

_Py_CODEUNIT *instr,

_PyExecutorObject **exec)

{

PyErr_Format(PyExc_SystemError, "Should never call error_optimize");

return -1;

}

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;

}

assert(interp->optimizer_backedge_threshold == interp->optimizer->backedge_threshold);

assert(interp->optimizer_resume_threshold == interp->optimizer->resume_threshold);

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)

{

PyCodeObject *code = (PyCodeObject *)frame->f_executable;

assert(PyCode_Check(code));

PyInterpreterState *interp = _PyInterpreterState_GET();

if (!has_space_for_executor(code, src)) {

goto jump_to_destination;

}

_PyOptimizerObject *opt = interp->optimizer;

_PyExecutorObject *executor = NULL;

int err = opt->optimize(opt, code, dest, &executor);

if (err <= 0) {

assert(executor == NULL);

if (err < 0) {

return NULL;

}

goto jump_to_destination;

}

int index = get_index_for_executor(code, src);

if (index < 0) {

/* Out of memory. Don't raise and assume that the

* error will show up elsewhere.

*

* If an optimizer has already produced an executor,

* it might get confused by the executor disappearing,

* but there is not much we can do about that here. */

Py_DECREF(executor);

goto jump_to_destination;

}

insert_executor(code, src, index, executor);

assert(frame->prev_instr == src);

frame->prev_instr = dest - 1;

return executor->execute(executor, frame, stack_pointer);

jump_to_destination:

frame->prev_instr = dest - 1;

_PyFrame_SetStackPointer(frame, stack_pointer);

return frame;

}

_PyExecutorObject *

PyUnstable_GetExecutor(PyCodeObject *code, int offset)

{

int code_len = (int)Py_SIZE(code);

for (int i = 0 ; i < code_len;) {

if (_PyCode_CODE(code)[i].op.code == ENTER_EXECUTOR && i*2 == offset) {

int oparg = _PyCode_CODE(code)[i].op.arg;

_PyExecutorObject *res = code->co_executors->executors[oparg];

Py_INCREF(res);

return res;

}

i += _PyInstruction_GetLength(code, i);

}

PyErr_SetString(PyExc_ValueError, "no executor at given byte offset");

return NULL;

}

/** 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 int

counter_optimize(

_PyOptimizerObject* self,

PyCodeObject *code,

_Py_CODEUNIT *instr,

_PyExecutorObject **exec_ptr)

{

_PyCounterExecutorObject *executor = (_PyCounterExecutorObject *)_PyObject_New(&CounterExecutor_Type);

if (executor == NULL) {

return -1;

}

executor->executor.execute = counter_execute;

Py_INCREF(self);

executor->optimizer = (_PyCounterOptimizerObject *)self;

executor->next_instr = instr;

*exec_ptr = (_PyExecutorObject *)executor;

return 1;

}

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;

}

///////////////////// Experimental UOp Optimizer /////////////////////

static void

uop_dealloc(_PyUOpExecutorObject *self) {

PyObject_Free(self);

}

static const char *

uop_name(int index) {

if (index < 256) {

return _PyOpcode_OpName[index];

}

return _PyOpcode_uop_name[index];

}

static Py_ssize_t

uop_len(_PyUOpExecutorObject *self)

{

int count = 0;

for (; count < _Py_UOP_MAX_TRACE_LENGTH; count++) {

if (self->trace[count].opcode == 0) {

break;

}

}

return count;

}

static PyObject *

uop_item(_PyUOpExecutorObject *self, Py_ssize_t index)

{

Py_ssize_t len = uop_len(self);

if (index < 0 || index >= len) {

PyErr_SetNone(PyExc_IndexError);

return NULL;

}

const char *name = uop_name(self->trace[index].opcode);

if (name == NULL) {

name = "<nil>";

}

PyObject *oname = _PyUnicode_FromASCII(name, strlen(name));

if (oname == NULL) {

return NULL;

}

PyObject *operand = PyLong_FromUnsignedLongLong(self->trace[index].operand);

if (operand == NULL) {

Py_DECREF(oname);

return NULL;

}

PyObject *args[2] = { oname, operand };

return _PyTuple_FromArraySteal(args, 2);

}

PySequenceMethods uop_as_sequence = {

.sq_length = (lenfunc)uop_len,

.sq_item = (ssizeargfunc)uop_item,

};

static PyTypeObject UOpExecutor_Type = {

PyVarObject_HEAD_INIT(&PyType_Type, 0)

.tp_name = "uop_executor",

.tp_basicsize = sizeof(_PyUOpExecutorObject),

.tp_itemsize = 0,

.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_DISALLOW_INSTANTIATION,

.tp_dealloc = (destructor)uop_dealloc,

.tp_as_sequence = &uop_as_sequence,

};

static int

translate_bytecode_to_trace(

PyCodeObject *code,

_Py_CODEUNIT *instr,

_PyUOpInstruction *trace,

int buffer_size)

{

_Py_CODEUNIT *initial_instr = instr;

int trace_length = 0;

int max_length = buffer_size;

#ifdef Py_DEBUG

char *uop_debug = Py_GETENV("PYTHONUOPSDEBUG");

int lltrace = 0;

if (uop_debug != NULL && *uop_debug >= '0') {

lltrace = *uop_debug - '0'; // TODO: Parse an int and all that

}

#define DPRINTF(level, ...) \

if (lltrace >= (level)) { fprintf(stderr, __VA_ARGS__); }

#else

#define DPRINTF(level, ...)

#endif

#define ADD_TO_TRACE(OPCODE, OPERAND) \

DPRINTF(2, \

" ADD_TO_TRACE(%s, %" PRIu64 ")\n", \

(OPCODE) < 256 ? _PyOpcode_OpName[(OPCODE)] : _PyOpcode_uop_name[(OPCODE)], \

(uint64_t)(OPERAND)); \

assert(trace_length < max_length); \

trace[trace_length].opcode = (OPCODE); \

trace[trace_length].operand = (OPERAND); \

trace_length++;

#define ADD_TO_STUB(INDEX, OPCODE, OPERAND) \

DPRINTF(2, " ADD_TO_STUB(%d, %s, %" PRIu64 ")\n", \

(INDEX), \

(OPCODE) < 256 ? _PyOpcode_OpName[(OPCODE)] : _PyOpcode_uop_name[(OPCODE)], \

(uint64_t)(OPERAND)); \

trace[(INDEX)].opcode = (OPCODE); \

trace[(INDEX)].operand = (OPERAND);

DPRINTF(4,

"Optimizing %s (%s:%d) at byte offset %ld\n",

PyUnicode_AsUTF8(code->co_qualname),

PyUnicode_AsUTF8(code->co_filename),

code->co_firstlineno,

2 * (long)(initial_instr - (_Py_CODEUNIT *)code->co_code_adaptive));

for (;;) {

ADD_TO_TRACE(SAVE_IP, instr - (_Py_CODEUNIT *)code->co_code_adaptive);

int opcode = instr->op.code;

int oparg = instr->op.arg;

int extras = 0;

while (opcode == EXTENDED_ARG) {

instr++;

extras += 1;

opcode = instr->op.code;

oparg = (oparg << 8) | instr->op.arg;

}

if (opcode == ENTER_EXECUTOR) {

_PyExecutorObject *executor =

(_PyExecutorObject *)code->co_executors->executors[oparg&255];

opcode = executor->vm_data.opcode;

DPRINTF(2, " * ENTER_EXECUTOR -> %s\n", _PyOpcode_OpName[opcode]);

oparg = (oparg & 0xffffff00) | executor->vm_data.oparg;

}

switch (opcode) {

case POP_JUMP_IF_FALSE:

case POP_JUMP_IF_TRUE:

{

// Assume jump unlikely (TODO: handle jump likely case)

// Reserve 5 entries (1 here, 2 stub, plus SAVE_IP + EXIT_TRACE)

if (trace_length + 5 > max_length) {

DPRINTF(1, "Ran out of space for POP_JUMP_IF_FALSE\n");

goto done;

}

_Py_CODEUNIT *target_instr =

instr + 1 + _PyOpcode_Caches[_PyOpcode_Deopt[opcode]] + oparg;

max_length -= 2; // Really the start of the stubs

int uopcode = opcode == POP_JUMP_IF_TRUE ?

_POP_JUMP_IF_TRUE : _POP_JUMP_IF_FALSE;

ADD_TO_TRACE(uopcode, max_length);

ADD_TO_STUB(max_length, SAVE_IP,

target_instr - (_Py_CODEUNIT *)code->co_code_adaptive);

ADD_TO_STUB(max_length + 1, EXIT_TRACE, 0);

break;

}

case JUMP_BACKWARD:

{

if (instr + 2 - oparg == initial_instr

&& trace_length + 3 <= max_length)

{

ADD_TO_TRACE(JUMP_TO_TOP, 0);

}

else {

DPRINTF(2, "JUMP_BACKWARD not to top ends trace\n");

}

goto done;

}

default:

{

const struct opcode_macro_expansion *expansion = &_PyOpcode_macro_expansion[opcode];

if (expansion->nuops > 0) {

// Reserve space for nuops (+ SAVE_IP + EXIT_TRACE)

int nuops = expansion->nuops;

if (trace_length + nuops + 2 > max_length) {

DPRINTF(1,

"Ran out of space for %s\n",

opcode < 256 ? _PyOpcode_OpName[opcode] : _PyOpcode_uop_name[opcode]);

goto done;

}

for (int i = 0; i < nuops; i++) {

uint64_t operand;

int offset = expansion->uops[i].offset;

switch (expansion->uops[i].size) {

case OPARG_FULL:

operand = oparg;

if (extras && OPCODE_HAS_JUMP(opcode)) {

if (opcode == JUMP_BACKWARD_NO_INTERRUPT) {

operand -= extras;

}

else {

assert(opcode != JUMP_BACKWARD);

operand += extras;

}

}

break;

case OPARG_CACHE_1:

operand = read_u16(&instr[offset].cache);

break;

case OPARG_CACHE_2:

operand = read_u32(&instr[offset].cache);

break;

case OPARG_CACHE_4:

operand = read_u64(&instr[offset].cache);

break;

case OPARG_TOP: // First half of super-instr

operand = oparg >> 4;

break;

case OPARG_BOTTOM: // Second half of super-instr

operand = oparg & 0xF;

break;

default:

fprintf(stderr,

"opcode=%d, oparg=%d; nuops=%d, i=%d; size=%d, offset=%d\n",

opcode, oparg, nuops, i,

expansion->uops[i].size,

expansion->uops[i].offset);

Py_FatalError("garbled expansion");

}

ADD_TO_TRACE(expansion->uops[i].uop, operand);

}

break;

}

DPRINTF(2,

"Unsupported opcode %s\n",

opcode < 256 ? _PyOpcode_OpName[opcode] : _PyOpcode_uop_name[opcode]);

goto done; // Break out of loop

}

}

instr++;

// Add cache size for opcode

instr += _PyOpcode_Caches[_PyOpcode_Deopt[opcode]];

}

done:

// Skip short traces like SAVE_IP, LOAD_FAST, SAVE_IP, EXIT_TRACE

if (trace_length > 3) {

ADD_TO_TRACE(EXIT_TRACE, 0);

DPRINTF(1,

"Created a trace for %s (%s:%d) at byte offset %ld -- length %d\n",

PyUnicode_AsUTF8(code->co_qualname),

PyUnicode_AsUTF8(code->co_filename),

code->co_firstlineno,

2 * (long)(initial_instr - (_Py_CODEUNIT *)code->co_code_adaptive),

trace_length);

if (max_length < buffer_size && trace_length < max_length) {

// Move the stubs back to be immediately after the main trace

// (which ends at trace_length)

DPRINTF(2,

"Moving %d stub uops back by %d\n",

buffer_size - max_length,

max_length - trace_length);

memmove(trace + trace_length,

trace + max_length,

(buffer_size - max_length) * sizeof(_PyUOpInstruction));

// Patch up the jump targets

for (int i = 0; i < trace_length; i++) {

if (trace[i].opcode == _POP_JUMP_IF_FALSE ||

trace[i].opcode == _POP_JUMP_IF_TRUE)

{

uint64_t target = trace[i].operand;

if (target >= (uint64_t)max_length) {

target += trace_length - max_length;

trace[i].operand = target;

}

}

}

trace_length += buffer_size - max_length;

}

return trace_length;

}

else {

DPRINTF(4,

"No trace for %s (%s:%d) at byte offset %ld\n",

PyUnicode_AsUTF8(code->co_qualname),

PyUnicode_AsUTF8(code->co_filename),

code->co_firstlineno,

2 * (long)(initial_instr - (_Py_CODEUNIT *)code->co_code_adaptive));

}

return 0;

#undef ADD_TO_TRACE

#undef DPRINTF

}

static int

uop_optimize(

_PyOptimizerObject *self,

PyCodeObject *code,

_Py_CODEUNIT *instr,

_PyExecutorObject **exec_ptr)

{

_PyUOpInstruction trace[_Py_UOP_MAX_TRACE_LENGTH];

int trace_length = translate_bytecode_to_trace(code, instr, trace, _Py_UOP_MAX_TRACE_LENGTH);

if (trace_length <= 0) {

// Error or nothing translated

return trace_length;

}

OBJECT_STAT_INC(optimization_traces_created);

_PyUOpExecutorObject *executor = PyObject_New(_PyUOpExecutorObject, &UOpExecutor_Type);

if (executor == NULL) {

return -1;

}

executor->base.execute = _PyUopExecute;

memcpy(executor->trace, trace, trace_length * sizeof(_PyUOpInstruction));

if (trace_length < _Py_UOP_MAX_TRACE_LENGTH) {

executor->trace[trace_length].opcode = 0; // Sentinel

}

*exec_ptr = (_PyExecutorObject *)executor;

return 1;

}

static void

uop_opt_dealloc(PyObject *self) {

PyObject_Free(self);

}

static PyTypeObject UOpOptimizer_Type = {

PyVarObject_HEAD_INIT(&PyType_Type, 0)

.tp_name = "uop_optimizer",

.tp_basicsize = sizeof(_PyOptimizerObject),

.tp_itemsize = 0,

.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_DISALLOW_INSTANTIATION,

.tp_dealloc = uop_opt_dealloc,

};

PyObject *

PyUnstable_Optimizer_NewUOpOptimizer(void)

{

_PyOptimizerObject *opt = PyObject_New(_PyOptimizerObject, &UOpOptimizer_Type);

if (opt == NULL) {

return NULL;

}

opt->optimize = uop_optimize;

opt->resume_threshold = UINT16_MAX;

// Need at least 3 iterations to settle specializations.

// A few lower bits of the counter are reserved for other flags.

opt->backedge_threshold = 3 << OPTIMIZER_BITS_IN_COUNTER;

return (PyObject *)opt;

}