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optimizer.c
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optimizer.c
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#include "Python.h"
#include "opcode.h"
#include "pycore_interp.h"
#include "pycore_bitutils.h" // _Py_popcount32()
#include "pycore_object.h" // _PyObject_GC_UNTRACK()
#include "pycore_opcode_metadata.h" // _PyOpcode_OpName[]
#include "pycore_opcode_utils.h" // MAX_REAL_OPCODE
#include "pycore_optimizer.h" // _Py_uop_analyze_and_optimize()
#include "pycore_pystate.h" // _PyInterpreterState_GET()
#include "pycore_uop_ids.h"
#include "pycore_jit.h"
#include "cpython/optimizer.h"
#include <stdbool.h>
#include <stdint.h>
#include <stddef.h>
#define NEED_OPCODE_METADATA
#include "pycore_uop_metadata.h" // Uop tables
#undef NEED_OPCODE_METADATA
#define MAX_EXECUTORS_SIZE 256
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 < MAX_EXECUTORS_SIZE;
}
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 < MAX_EXECUTORS_SIZE);
}
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);
_Py_ExecutorClear(code->co_executors->executors[index]);
}
else {
assert(code->co_executors->size == index);
assert(code->co_executors->capacity > index);
code->co_executors->size++;
}
executor->vm_data.opcode = instr->op.code;
executor->vm_data.oparg = instr->op.arg;
executor->vm_data.code = code;
executor->vm_data.index = (int)(instr - _PyCode_CODE(code));
code->co_executors->executors[index] = executor;
assert(index < MAX_EXECUTORS_SIZE);
instr->op.code = ENTER_EXECUTOR;
instr->op.arg = index;
}
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
never_optimize(
_PyOptimizerObject* self,
_PyInterpreterFrame *frame,
_Py_CODEUNIT *instr,
_PyExecutorObject **exec,
int Py_UNUSED(stack_entries))
{
/* Although it should be benign for this to be called,
* it shouldn't happen, so fail in debug builds. */
assert(0 && "never optimize should never be called");
return 0;
}
PyTypeObject _PyDefaultOptimizer_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,
};
static _PyOptimizerObject _PyOptimizer_Default = {
PyObject_HEAD_INIT(&_PyDefaultOptimizer_Type)
.optimize = never_optimize,
.resume_threshold = OPTIMIZER_UNREACHABLE_THRESHOLD,
.backedge_threshold = OPTIMIZER_UNREACHABLE_THRESHOLD,
.side_threshold = OPTIMIZER_UNREACHABLE_THRESHOLD,
};
static uint32_t
shift_and_offset_threshold(uint32_t threshold)
{
return (threshold << OPTIMIZER_BITS_IN_COUNTER) + (1 << 15);
}
_PyOptimizerObject *
PyUnstable_GetOptimizer(void)
{
PyInterpreterState *interp = _PyInterpreterState_GET();
assert(interp->optimizer_backedge_threshold ==
shift_and_offset_threshold(interp->optimizer->backedge_threshold));
assert(interp->optimizer_resume_threshold ==
shift_and_offset_threshold(interp->optimizer->resume_threshold));
if (interp->optimizer == &_PyOptimizer_Default) {
return NULL;
}
Py_INCREF(interp->optimizer);
return interp->optimizer;
}
static _PyExecutorObject *
make_executor_from_uops(_PyUOpInstruction *buffer, const _PyBloomFilter *dependencies);
static int
init_cold_exit_executor(_PyExecutorObject *executor, int oparg);
static int cold_exits_initialized = 0;
static _PyExecutorObject COLD_EXITS[UOP_MAX_TRACE_LENGTH] = { 0 };
static const _PyBloomFilter EMPTY_FILTER = { 0 };
_PyOptimizerObject *
_Py_SetOptimizer(PyInterpreterState *interp, _PyOptimizerObject *optimizer)
{
if (optimizer == NULL) {
optimizer = &_PyOptimizer_Default;
}
else if (cold_exits_initialized == 0) {
cold_exits_initialized = 1;
for (int i = 0; i < UOP_MAX_TRACE_LENGTH; i++) {
if (init_cold_exit_executor(&COLD_EXITS[i], i)) {
return NULL;
}
}
}
_PyOptimizerObject *old = interp->optimizer;
if (old == NULL) {
old = &_PyOptimizer_Default;
}
Py_INCREF(optimizer);
interp->optimizer = optimizer;
interp->optimizer_backedge_threshold = shift_and_offset_threshold(optimizer->backedge_threshold);
interp->optimizer_resume_threshold = shift_and_offset_threshold(optimizer->resume_threshold);
interp->optimizer_side_threshold = optimizer->side_threshold;
if (optimizer == &_PyOptimizer_Default) {
assert(interp->optimizer_backedge_threshold > (1 << 16));
assert(interp->optimizer_resume_threshold > (1 << 16));
}
return old;
}
int
PyUnstable_SetOptimizer(_PyOptimizerObject *optimizer)
{
PyInterpreterState *interp = _PyInterpreterState_GET();
_PyOptimizerObject *old = _Py_SetOptimizer(interp, optimizer);
Py_XDECREF(old);
return old == NULL ? -1 : 0;
}
/* Returns 1 if optimized, 0 if not optimized, and -1 for an error.
* If optimized, *executor_ptr contains a new reference to the executor
*/
int
_PyOptimizer_Optimize(
_PyInterpreterFrame *frame, _Py_CODEUNIT *start,
PyObject **stack_pointer, _PyExecutorObject **executor_ptr)
{
PyCodeObject *code = (PyCodeObject *)frame->f_executable;
assert(PyCode_Check(code));
PyInterpreterState *interp = _PyInterpreterState_GET();
if (!has_space_for_executor(code, start)) {
return 0;
}
_PyOptimizerObject *opt = interp->optimizer;
int err = opt->optimize(opt, frame, start, executor_ptr, (int)(stack_pointer - _PyFrame_Stackbase(frame)));
if (err <= 0) {
return err;
}
assert(*executor_ptr != NULL);
int index = get_index_for_executor(code, start);
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_ptr);
return 0;
}
insert_executor(code, start, index, *executor_ptr);
assert((*executor_ptr)->vm_data.valid);
return 1;
}
_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;
}
static PyObject *
is_valid(PyObject *self, PyObject *Py_UNUSED(ignored))
{
return PyBool_FromLong(((_PyExecutorObject *)self)->vm_data.valid);
}
static PyObject *
get_opcode(PyObject *self, PyObject *Py_UNUSED(ignored))
{
return PyLong_FromUnsignedLong(((_PyExecutorObject *)self)->vm_data.opcode);
}
static PyObject *
get_oparg(PyObject *self, PyObject *Py_UNUSED(ignored))
{
return PyLong_FromUnsignedLong(((_PyExecutorObject *)self)->vm_data.oparg);
}
static PyMethodDef executor_methods[] = {
{ "is_valid", is_valid, METH_NOARGS, NULL },
{ "get_opcode", get_opcode, METH_NOARGS, NULL },
{ "get_oparg", get_oparg, METH_NOARGS, NULL },
{ NULL, NULL },
};
///////////////////// Experimental UOp Optimizer /////////////////////
static void
uop_dealloc(_PyExecutorObject *self) {
_PyObject_GC_UNTRACK(self);
_Py_ExecutorClear(self);
#ifdef _Py_JIT
_PyJIT_Free(self);
#endif
PyObject_GC_Del(self);
}
const char *
_PyUOpName(int index)
{
if (index < 0 || index > MAX_UOP_ID) {
return NULL;
}
return _PyOpcode_uop_name[index];
}
#ifdef Py_DEBUG
void
_PyUOpPrint(const _PyUOpInstruction *uop)
{
const char *name = _PyUOpName(uop->opcode);
if (name == NULL) {
printf("<uop %d>", uop->opcode);
}
else {
printf("%s", name);
}
printf(" (%d, target=%d, operand=%" PRIx64 ")",
uop->oparg,
uop->target,
(uint64_t)uop->operand);
}
#endif
static Py_ssize_t
uop_len(_PyExecutorObject *self)
{
return self->code_size;
}
static PyObject *
uop_item(_PyExecutorObject *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 = _PyUOpName(self->trace[index].opcode);
if (name == NULL) {
name = "<nil>";
}
PyObject *oname = _PyUnicode_FromASCII(name, strlen(name));
if (oname == NULL) {
return NULL;
}
PyObject *oparg = PyLong_FromUnsignedLong(self->trace[index].oparg);
if (oparg == NULL) {
Py_DECREF(oname);
return NULL;
}
PyObject *target = PyLong_FromUnsignedLong(self->trace[index].target);
if (oparg == NULL) {
Py_DECREF(oparg);
Py_DECREF(oname);
return NULL;
}
PyObject *operand = PyLong_FromUnsignedLongLong(self->trace[index].operand);
if (operand == NULL) {
Py_DECREF(target);
Py_DECREF(oparg);
Py_DECREF(oname);
return NULL;
}
PyObject *args[4] = { oname, oparg, target, operand };
return _PyTuple_FromArraySteal(args, 4);
}
PySequenceMethods uop_as_sequence = {
.sq_length = (lenfunc)uop_len,
.sq_item = (ssizeargfunc)uop_item,
};
static int
executor_clear(PyObject *o)
{
_Py_ExecutorClear((_PyExecutorObject *)o);
return 0;
}
static int
executor_traverse(PyObject *o, visitproc visit, void *arg)
{
_PyExecutorObject *executor = (_PyExecutorObject *)o;
for (uint32_t i = 0; i < executor->exit_count; i++) {
Py_VISIT(executor->exits[i].executor);
}
return 0;
}
PyTypeObject _PyUOpExecutor_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
.tp_name = "uop_executor",
.tp_basicsize = offsetof(_PyExecutorObject, exits),
.tp_itemsize = 1,
.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_DISALLOW_INSTANTIATION | Py_TPFLAGS_HAVE_GC,
.tp_dealloc = (destructor)uop_dealloc,
.tp_as_sequence = &uop_as_sequence,
.tp_methods = executor_methods,
.tp_traverse = executor_traverse,
.tp_clear = executor_clear,
};
/* TO DO -- Generate these tables */
static const uint16_t
_PyUOp_Replacements[MAX_UOP_ID + 1] = {
[_ITER_JUMP_RANGE] = _GUARD_NOT_EXHAUSTED_RANGE,
[_ITER_JUMP_LIST] = _GUARD_NOT_EXHAUSTED_LIST,
[_ITER_JUMP_TUPLE] = _GUARD_NOT_EXHAUSTED_TUPLE,
[_FOR_ITER] = _FOR_ITER_TIER_TWO,
};
static const uint16_t
BRANCH_TO_GUARD[4][2] = {
[POP_JUMP_IF_FALSE - POP_JUMP_IF_FALSE][0] = _GUARD_IS_TRUE_POP,
[POP_JUMP_IF_FALSE - POP_JUMP_IF_FALSE][1] = _GUARD_IS_FALSE_POP,
[POP_JUMP_IF_TRUE - POP_JUMP_IF_FALSE][0] = _GUARD_IS_FALSE_POP,
[POP_JUMP_IF_TRUE - POP_JUMP_IF_FALSE][1] = _GUARD_IS_TRUE_POP,
[POP_JUMP_IF_NONE - POP_JUMP_IF_FALSE][0] = _GUARD_IS_NOT_NONE_POP,
[POP_JUMP_IF_NONE - POP_JUMP_IF_FALSE][1] = _GUARD_IS_NONE_POP,
[POP_JUMP_IF_NOT_NONE - POP_JUMP_IF_FALSE][0] = _GUARD_IS_NONE_POP,
[POP_JUMP_IF_NOT_NONE - POP_JUMP_IF_FALSE][1] = _GUARD_IS_NOT_NONE_POP,
};
#define CONFIDENCE_RANGE 1000
#define CONFIDENCE_CUTOFF 333
#ifdef Py_DEBUG
#define DPRINTF(level, ...) \
if (lltrace >= (level)) { printf(__VA_ARGS__); }
#else
#define DPRINTF(level, ...)
#endif
// Beware: Macro arg order differs from struct member order
#ifdef Py_DEBUG
#define ADD_TO_TRACE(OPCODE, OPARG, OPERAND, TARGET) \
assert(trace_length < max_length); \
trace[trace_length].opcode = (OPCODE); \
trace[trace_length].oparg = (OPARG); \
trace[trace_length].target = (TARGET); \
trace[trace_length].operand = (OPERAND); \
if (lltrace >= 2) { \
printf("%4d ADD_TO_TRACE: ", trace_length); \
_PyUOpPrint(&trace[trace_length]); \
printf("\n"); \
} \
trace_length++;
#else
#define ADD_TO_TRACE(OPCODE, OPARG, OPERAND, TARGET) \
assert(trace_length < max_length); \
trace[trace_length].opcode = (OPCODE); \
trace[trace_length].oparg = (OPARG); \
trace[trace_length].target = (TARGET); \
trace[trace_length].operand = (OPERAND); \
trace_length++;
#endif
#define INSTR_IP(INSTR, CODE) \
((uint32_t)((INSTR) - ((_Py_CODEUNIT *)(CODE)->co_code_adaptive)))
// Reserve space for n uops
#define RESERVE_RAW(n, opname) \
if (trace_length + (n) > max_length) { \
DPRINTF(2, "No room for %s (need %d, got %d)\n", \
(opname), (n), max_length - trace_length); \
OPT_STAT_INC(trace_too_long); \
goto done; \
}
// Reserve space for N uops, plus 3 for _SET_IP, _CHECK_VALIDITY and _EXIT_TRACE
#define RESERVE(needed) RESERVE_RAW((needed) + 3, _PyUOpName(opcode))
// Trace stack operations (used by _PUSH_FRAME, _POP_FRAME)
#define TRACE_STACK_PUSH() \
if (trace_stack_depth >= TRACE_STACK_SIZE) { \
DPRINTF(2, "Trace stack overflow\n"); \
OPT_STAT_INC(trace_stack_overflow); \
ADD_TO_TRACE(_EXIT_TRACE, 0, 0, 0); \
goto done; \
} \
assert(func->func_code == (PyObject *)code); \
trace_stack[trace_stack_depth].func = func; \
trace_stack[trace_stack_depth].instr = instr; \
trace_stack_depth++;
#define TRACE_STACK_POP() \
if (trace_stack_depth <= 0) { \
Py_FatalError("Trace stack underflow\n"); \
} \
trace_stack_depth--; \
func = trace_stack[trace_stack_depth].func; \
code = (PyCodeObject *)trace_stack[trace_stack_depth].func->func_code; \
instr = trace_stack[trace_stack_depth].instr;
/* Returns 1 on success,
* 0 if it failed to produce a worthwhile trace,
* and -1 on an error.
*/
static int
translate_bytecode_to_trace(
_PyInterpreterFrame *frame,
_Py_CODEUNIT *instr,
_PyUOpInstruction *trace,
int buffer_size,
_PyBloomFilter *dependencies)
{
bool progress_needed = true;
PyCodeObject *code = (PyCodeObject *)frame->f_executable;
PyFunctionObject *func = (PyFunctionObject *)frame->f_funcobj;
assert(PyFunction_Check(func));
PyCodeObject *initial_code = code;
_Py_BloomFilter_Add(dependencies, initial_code);
_Py_CODEUNIT *initial_instr = instr;
int trace_length = 0;
int max_length = buffer_size;
struct {
PyFunctionObject *func;
_Py_CODEUNIT *instr;
} trace_stack[TRACE_STACK_SIZE];
int trace_stack_depth = 0;
int confidence = CONFIDENCE_RANGE; // Adjusted by branch instructions
#ifdef Py_DEBUG
char *python_lltrace = Py_GETENV("PYTHON_LLTRACE");
int lltrace = 0;
if (python_lltrace != NULL && *python_lltrace >= '0') {
lltrace = *python_lltrace - '0'; // TODO: Parse an int and all that
}
#endif
DPRINTF(4,
"Optimizing %s (%s:%d) at byte offset %d\n",
PyUnicode_AsUTF8(code->co_qualname),
PyUnicode_AsUTF8(code->co_filename),
code->co_firstlineno,
2 * INSTR_IP(initial_instr, code));
uint32_t target = 0;
top: // Jump here after _PUSH_FRAME or likely branches
for (;;) {
target = INSTR_IP(instr, code);
RESERVE_RAW(2, "epilogue"); // Always need space for _SET_IP, _CHECK_VALIDITY and _EXIT_TRACE
ADD_TO_TRACE(_CHECK_VALIDITY_AND_SET_IP, 0, (uintptr_t)instr, target);
uint32_t opcode = instr->op.code;
uint32_t oparg = instr->op.arg;
uint32_t extended = 0;
DPRINTF(3, "%d: %s(%d)\n", target, _PyOpcode_OpName[opcode], oparg);
if (opcode == ENTER_EXECUTOR) {
assert(oparg < 256);
_PyExecutorObject *executor = code->co_executors->executors[oparg];
opcode = executor->vm_data.opcode;
DPRINTF(2, " * ENTER_EXECUTOR -> %s\n", _PyOpcode_OpName[opcode]);
oparg = executor->vm_data.oparg;
}
if (opcode == EXTENDED_ARG) {
instr++;
extended = 1;
opcode = instr->op.code;
oparg = (oparg << 8) | instr->op.arg;
if (opcode == EXTENDED_ARG) {
instr--;
goto done;
}
}
assert(opcode != ENTER_EXECUTOR && opcode != EXTENDED_ARG);
/* Special case the first instruction,
* so that we can guarantee forward progress */
if (progress_needed) {
progress_needed = false;
if (opcode == JUMP_BACKWARD || opcode == JUMP_BACKWARD_NO_INTERRUPT) {
instr += 1 + _PyOpcode_Caches[opcode] - (int32_t)oparg;
initial_instr = instr;
continue;
}
else {
if (OPCODE_HAS_DEOPT(opcode)) {
opcode = _PyOpcode_Deopt[opcode];
}
assert(!OPCODE_HAS_DEOPT(opcode));
}
}
switch (opcode) {
case POP_JUMP_IF_NONE:
case POP_JUMP_IF_NOT_NONE:
case POP_JUMP_IF_FALSE:
case POP_JUMP_IF_TRUE:
{
RESERVE(1);
int counter = instr[1].cache;
int bitcount = _Py_popcount32(counter);
int jump_likely = bitcount > 8;
/* If bitcount is 8 (half the jumps were taken), adjust confidence by 50%.
If it's 16 or 0 (all or none were taken), adjust by 10%
(since the future is still somewhat uncertain).
For values in between, adjust proportionally. */
if (jump_likely) {
confidence = confidence * (bitcount + 2) / 20;
}
else {
confidence = confidence * (18 - bitcount) / 20;
}
uint32_t uopcode = BRANCH_TO_GUARD[opcode - POP_JUMP_IF_FALSE][jump_likely];
DPRINTF(2, "%d: %s(%d): counter=%x, bitcount=%d, likely=%d, confidence=%d, uopcode=%s\n",
target, _PyOpcode_OpName[opcode], oparg,
counter, bitcount, jump_likely, confidence, _PyUOpName(uopcode));
if (confidence < CONFIDENCE_CUTOFF) {
DPRINTF(2, "Confidence too low (%d < %d)\n", confidence, CONFIDENCE_CUTOFF);
OPT_STAT_INC(low_confidence);
goto done;
}
_Py_CODEUNIT *next_instr = instr + 1 + _PyOpcode_Caches[_PyOpcode_Deopt[opcode]];
_Py_CODEUNIT *target_instr = next_instr + oparg;
if (jump_likely) {
DPRINTF(2, "Jump likely (%x = %d bits), continue at byte offset %d\n",
instr[1].cache, bitcount, 2 * INSTR_IP(target_instr, code));
instr = target_instr;
ADD_TO_TRACE(uopcode, max_length, 0, INSTR_IP(next_instr, code));
goto top;
}
ADD_TO_TRACE(uopcode, max_length, 0, INSTR_IP(target_instr, code));
break;
}
case JUMP_BACKWARD:
case JUMP_BACKWARD_NO_INTERRUPT:
{
_Py_CODEUNIT *target = instr + 1 + _PyOpcode_Caches[opcode] - (int)oparg;
if (target == initial_instr) {
/* We have looped round to the start */
RESERVE(1);
ADD_TO_TRACE(_JUMP_TO_TOP, 0, 0, 0);
}
else {
OPT_STAT_INC(inner_loop);
DPRINTF(2, "JUMP_BACKWARD not to top ends trace\n");
}
goto done;
}
case JUMP_FORWARD:
{
RESERVE(0);
// This will emit two _SET_IP instructions; leave it to the optimizer
instr += oparg;
break;
}
default:
{
const struct opcode_macro_expansion *expansion = &_PyOpcode_macro_expansion[opcode];
if (expansion->nuops > 0) {
// Reserve space for nuops (+ _SET_IP + _EXIT_TRACE)
int nuops = expansion->nuops;
RESERVE(nuops);
if (expansion->uops[nuops-1].uop == _POP_FRAME) {
// Check for trace stack underflow now:
// We can't bail e.g. in the middle of
// LOAD_CONST + _POP_FRAME.
if (trace_stack_depth == 0) {
DPRINTF(2, "Trace stack underflow\n");
OPT_STAT_INC(trace_stack_underflow);
goto done;
}
}
uint32_t orig_oparg = oparg; // For OPARG_TOP/BOTTOM
for (int i = 0; i < nuops; i++) {
oparg = orig_oparg;
uint32_t uop = expansion->uops[i].uop;
uint64_t operand = 0;
// Add one to account for the actual opcode/oparg pair:
int offset = expansion->uops[i].offset + 1;
switch (expansion->uops[i].size) {
case OPARG_FULL:
assert(opcode != JUMP_BACKWARD_NO_INTERRUPT && opcode != JUMP_BACKWARD);
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
oparg = orig_oparg >> 4;
break;
case OPARG_BOTTOM: // Second half of super-instr
oparg = orig_oparg & 0xF;
break;
case OPARG_SAVE_RETURN_OFFSET: // op=_SAVE_RETURN_OFFSET; oparg=return_offset
oparg = offset;
assert(uop == _SAVE_RETURN_OFFSET);
break;
case OPARG_REPLACED:
uop = _PyUOp_Replacements[uop];
assert(uop != 0);
if (uop == _FOR_ITER_TIER_TWO) {
target += 1 + INLINE_CACHE_ENTRIES_FOR_ITER + oparg + 2 + extended;
assert(_PyCode_CODE(code)[target-2].op.code == END_FOR ||
_PyCode_CODE(code)[target-2].op.code == INSTRUMENTED_END_FOR);
assert(_PyCode_CODE(code)[target-1].op.code == POP_TOP);
}
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(uop, oparg, operand, target);
if (uop == _POP_FRAME) {
TRACE_STACK_POP();
/* Set the operand to the function object returned to,
* to assist optimization passes */
trace[trace_length-1].operand = (uintptr_t)func;
DPRINTF(2,
"Returning to %s (%s:%d) at byte offset %d\n",
PyUnicode_AsUTF8(code->co_qualname),
PyUnicode_AsUTF8(code->co_filename),
code->co_firstlineno,
2 * INSTR_IP(instr, code));
goto top;
}
if (uop == _PUSH_FRAME) {
assert(i + 1 == nuops);
int func_version_offset =
offsetof(_PyCallCache, func_version)/sizeof(_Py_CODEUNIT)
// Add one to account for the actual opcode/oparg pair:
+ 1;
uint32_t func_version = read_u32(&instr[func_version_offset].cache);
PyFunctionObject *new_func = _PyFunction_LookupByVersion(func_version);
DPRINTF(3, "Function object: %p\n", func);
if (new_func != NULL) {
PyCodeObject *new_code = (PyCodeObject *)PyFunction_GET_CODE(new_func);
if (new_code == code) {
// Recursive call, bail (we could be here forever).
DPRINTF(2, "Bailing on recursive call to %s (%s:%d)\n",
PyUnicode_AsUTF8(new_code->co_qualname),
PyUnicode_AsUTF8(new_code->co_filename),
new_code->co_firstlineno);
OPT_STAT_INC(recursive_call);
ADD_TO_TRACE(_EXIT_TRACE, 0, 0, 0);
goto done;
}
if (new_code->co_version != func_version) {
// func.__code__ was updated.
// Perhaps it may happen again, so don't bother tracing.
// TODO: Reason about this -- is it better to bail or not?
DPRINTF(2, "Bailing because co_version != func_version\n");
ADD_TO_TRACE(_EXIT_TRACE, 0, 0, 0);
goto done;
}
// Increment IP to the return address
instr += _PyOpcode_Caches[_PyOpcode_Deopt[opcode]] + 1;
TRACE_STACK_PUSH();
_Py_BloomFilter_Add(dependencies, new_code);
/* Set the operand to the callee's code object,
* to assist optimization passes */
trace[trace_length-1].operand = (uintptr_t)new_func;
code = new_code;
func = new_func;
instr = _PyCode_CODE(code);
DPRINTF(2,
"Continuing in %s (%s:%d) at byte offset %d\n",
PyUnicode_AsUTF8(code->co_qualname),
PyUnicode_AsUTF8(code->co_filename),
code->co_firstlineno,
2 * INSTR_IP(instr, code));
goto top;
}
ADD_TO_TRACE(_EXIT_TRACE, 0, 0, 0);
goto done;
}
}
break;
}
DPRINTF(2, "Unsupported opcode %s\n", _PyOpcode_OpName[opcode]);
OPT_UNSUPPORTED_OPCODE(opcode);
goto done; // Break out of loop
} // End default
} // End switch (opcode)
instr++;
// Add cache size for opcode
instr += _PyOpcode_Caches[_PyOpcode_Deopt[opcode]];
} // End for (;;)
done:
while (trace_stack_depth > 0) {
TRACE_STACK_POP();
}
assert(code == initial_code);
// Skip short traces like _SET_IP, LOAD_FAST, _SET_IP, _EXIT_TRACE
if (progress_needed || trace_length < 5) {
OPT_STAT_INC(trace_too_short);
DPRINTF(4,
"No trace for %s (%s:%d) at byte offset %d\n",
PyUnicode_AsUTF8(code->co_qualname),
PyUnicode_AsUTF8(code->co_filename),
code->co_firstlineno,
2 * INSTR_IP(initial_instr, code));
return 0;
}
ADD_TO_TRACE(_EXIT_TRACE, 0, 0, target);
DPRINTF(1,
"Created a trace for %s (%s:%d) at byte offset %d -- length %d\n",
PyUnicode_AsUTF8(code->co_qualname),
PyUnicode_AsUTF8(code->co_filename),
code->co_firstlineno,
2 * INSTR_IP(initial_instr, code),
trace_length);
OPT_HIST(trace_length + buffer_size - max_length, trace_length_hist);
return 1;
}
#undef RESERVE
#undef RESERVE_RAW
#undef INSTR_IP
#undef ADD_TO_TRACE
#undef DPRINTF
#define UNSET_BIT(array, bit) (array[(bit)>>5] &= ~(1<<((bit)&31)))
#define SET_BIT(array, bit) (array[(bit)>>5] |= (1<<((bit)&31)))
#define BIT_IS_SET(array, bit) (array[(bit)>>5] & (1<<((bit)&31)))
/* Count the number of used uops, and mark them in the bit vector `used`.
* This can be done in a single pass using simple reachability analysis,
* as there are no backward jumps.
* NOPs are excluded from the count.
*/
static int
compute_used(_PyUOpInstruction *buffer, uint32_t *used, int *exit_count_ptr)
{
int count = 0;
int exit_count = 0;
SET_BIT(used, 0);
for (int i = 0; i < UOP_MAX_TRACE_LENGTH; i++) {
if (!BIT_IS_SET(used, i)) {
continue;
}
count++;
int opcode = buffer[i].opcode;
if (_PyUop_Flags[opcode] & HAS_EXIT_FLAG) {
exit_count++;
}
if (opcode == _JUMP_TO_TOP || opcode == _EXIT_TRACE) {
continue;
}
/* All other micro-ops fall through, so i+1 is reachable */
SET_BIT(used, i+1);
assert(opcode <= MAX_UOP_ID);
if (_PyUop_Flags[opcode] & HAS_JUMP_FLAG) {
/* Mark target as reachable */
SET_BIT(used, buffer[i].oparg);
}
if (opcode == NOP) {
count--;
UNSET_BIT(used, i);
}
}
*exit_count_ptr = exit_count;
return count;
}
/* Executor side exits */
static _PyExecutorObject *
allocate_executor(int exit_count, int length)
{
int size = exit_count*sizeof(_PyExitData) + length*sizeof(_PyUOpInstruction);
_PyExecutorObject *res = PyObject_GC_NewVar(_PyExecutorObject, &_PyUOpExecutor_Type, size);
if (res == NULL) {
return NULL;
}
res->trace = (_PyUOpInstruction *)(res->exits + exit_count);
res->code_size = length;
res->exit_count = exit_count;
return res;
}
/* Makes an executor from a buffer of uops.
* Account for the buffer having gaps and NOPs by computing a "used"
* bit vector and only copying the used uops. Here "used" means reachable
* and not a NOP.
*/
static _PyExecutorObject *
make_executor_from_uops(_PyUOpInstruction *buffer, const _PyBloomFilter *dependencies)
{
uint32_t used[(UOP_MAX_TRACE_LENGTH + 31)/32] = { 0 };
int exit_count;
int length = compute_used(buffer, used, &exit_count);
length += 1; // For _START_EXECUTOR
_PyExecutorObject *executor = allocate_executor(exit_count, length);
if (executor == NULL) {
return NULL;
}
/* Initialize exits */
for (int i = 0; i < exit_count; i++) {
executor->exits[i].executor = &COLD_EXITS[i];
executor->exits[i].temperature = 0;
}
int next_exit = exit_count-1;
_PyUOpInstruction *dest = (_PyUOpInstruction *)&executor->trace[length-1];
/* Scan backwards, so that we see the destinations of jumps before the jumps themselves. */
for (int i = UOP_MAX_TRACE_LENGTH-1; i >= 0; i--) {
if (!BIT_IS_SET(used, i)) {
continue;
}
*dest = buffer[i];
int opcode = buffer[i].opcode;
if (opcode == _POP_JUMP_IF_FALSE ||
opcode == _POP_JUMP_IF_TRUE)
{
/* The oparg of the target will already have been set to its new offset */
int oparg = dest->oparg;
dest->oparg = buffer[oparg].oparg;
}
if (_PyUop_Flags[opcode] & HAS_EXIT_FLAG) {
executor->exits[next_exit].target = buffer[i].target;
dest->exit_index = next_exit;
next_exit--;
}
/* Set the oparg to be the destination offset,
* so that we can set the oparg of earlier jumps correctly. */
buffer[i].oparg = (uint16_t)(dest - executor->trace);
dest--;
}
assert(next_exit == -1);
assert(dest == executor->trace);
dest->opcode = _START_EXECUTOR;
dest->operand = (uintptr_t)executor;
_Py_ExecutorInit(executor, dependencies);
#ifdef Py_DEBUG
char *python_lltrace = Py_GETENV("PYTHON_LLTRACE");
int lltrace = 0;
if (python_lltrace != NULL && *python_lltrace >= '0') {
lltrace = *python_lltrace - '0'; // TODO: Parse an int and all that
}
if (lltrace >= 2) {
printf("Optimized executor (length %d):\n", length);
for (int i = 0; i < length; i++) {
printf("%4d OPTIMIZED: ", i);
_PyUOpPrint(&executor->trace[i]);
printf("\n");
}
}
#endif
#ifdef _Py_JIT
executor->jit_code = NULL;
executor->jit_size = 0;
if (_PyJIT_Compile(executor, executor->trace, length)) {
Py_DECREF(executor);
return NULL;
}
#endif
_PyObject_GC_TRACK(executor);
return executor;
}
static int
init_cold_exit_executor(_PyExecutorObject *executor, int oparg)
{
_Py_SetImmortal(executor);
Py_SET_TYPE(executor, &_PyUOpExecutor_Type);
executor->trace = (_PyUOpInstruction *)executor->exits;
executor->code_size = 1;
executor->exit_count = 0;
_PyUOpInstruction *inst = (_PyUOpInstruction *)&executor->trace[0];
inst->opcode = _COLD_EXIT;
inst->oparg = oparg;
executor->vm_data.valid = true;
for (int i = 0; i < BLOOM_FILTER_WORDS; i++) {
assert(executor->vm_data.bloom.bits[i] == 0);
}
#ifdef _Py_JIT
executor->jit_code = NULL;
executor->jit_size = 0;
if (_PyJIT_Compile(executor, executor->trace, 1)) {
return -1;
}
#endif
return 0;
}
static int
uop_optimize(
_PyOptimizerObject *self,
_PyInterpreterFrame *frame,
_Py_CODEUNIT *instr,
_PyExecutorObject **exec_ptr,