#include "Python.h" #include "opcode.h" #include "pycore_interp.h" #include "pycore_bitutils.h" // _Py_popcount32() #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_uops.h" #include "cpython/optimizer.h" #include #include #include #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); _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 < MAX_EXECUTORS_SIZE); 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, int Py_UNUSED(stack_entries)) { PyErr_Format(PyExc_SystemError, "Should never call error_optimize"); return -1; } 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, }; _PyOptimizerObject _PyOptimizer_Default = { PyObject_HEAD_INIT(&_PyDefaultOptimizer_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); } int _PyOptimizer_BackEdge(_PyInterpreterFrame *frame, _Py_CODEUNIT *src, _Py_CODEUNIT *dest, PyObject **stack_pointer) { assert(src->op.code == JUMP_BACKWARD); PyCodeObject *code = (PyCodeObject *)frame->f_executable; assert(PyCode_Check(code)); PyInterpreterState *interp = _PyInterpreterState_GET(); if (!has_space_for_executor(code, src)) { return 0; } _PyOptimizerObject *opt = interp->optimizer; _PyExecutorObject *executor = NULL; int err = opt->optimize(opt, code, dest, &executor, (int)(stack_pointer - _PyFrame_Stackbase(frame))); if (err <= 0) { assert(executor == NULL); return err; } 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); return 0; } insert_executor(code, src, index, executor); Py_DECREF(executor); 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; } /** 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_ExecutorClear((_PyExecutorObject *)self); Py_DECREF(self->optimizer); PyObject_Free(self); } static PyObject * is_valid(PyObject *self, PyObject *Py_UNUSED(ignored)) { return PyBool_FromLong(((_PyExecutorObject *)self)->vm_data.valid); } static PyMethodDef executor_methods[] = { { "is_valid", is_valid, METH_NOARGS, NULL }, { NULL, NULL }, }; PyTypeObject _PyCounterExecutor_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, .tp_methods = executor_methods, }; static _PyInterpreterFrame * counter_execute(_PyExecutorObject *self, _PyInterpreterFrame *frame, PyObject **stack_pointer) { ((_PyCounterExecutorObject *)self)->optimizer->count++; _PyFrame_SetStackPointer(frame, stack_pointer); frame->instr_ptr = ((_PyCounterExecutorObject *)self)->next_instr; Py_DECREF(self); return frame; } static int counter_optimize( _PyOptimizerObject* self, PyCodeObject *code, _Py_CODEUNIT *instr, _PyExecutorObject **exec_ptr, int Py_UNUSED(curr_stackentries) ) { _PyCounterExecutorObject *executor = (_PyCounterExecutorObject *)_PyObject_New(&_PyCounterExecutor_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; _PyBloomFilter empty; _Py_BloomFilter_Init(&empty); _Py_ExecutorInit((_PyExecutorObject *)executor, &empty); return 1; } static PyObject * counter_get_counter(PyObject *self, PyObject *args) { return PyLong_FromLongLong(((_PyCounterOptimizerObject *)self)->count); } static PyMethodDef counter_optimizer_methods[] = { { "get_count", counter_get_counter, METH_NOARGS, NULL }, { NULL, NULL }, }; PyTypeObject _PyCounterOptimizer_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_optimizer_methods, .tp_dealloc = (destructor)PyObject_Del, }; PyObject * PyUnstable_Optimizer_NewCounter(void) { _PyCounterOptimizerObject *opt = (_PyCounterOptimizerObject *)_PyObject_New(&_PyCounterOptimizer_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) { _Py_ExecutorClear((_PyExecutorObject *)self); PyObject_Free(self); } static const char * uop_name(int index) { if (index <= MAX_REAL_OPCODE) { return _PyOpcode_OpName[index]; } return _PyOpcode_uop_name[index]; } static Py_ssize_t uop_len(_PyUOpExecutorObject *self) { return Py_SIZE(self); } 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 = ""; } 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 *operand = PyLong_FromUnsignedLongLong(self->trace[index].operand); if (operand == NULL) { Py_DECREF(oparg); Py_DECREF(oname); return NULL; } PyObject *args[3] = { oname, oparg, operand }; return _PyTuple_FromArraySteal(args, 3); } PySequenceMethods uop_as_sequence = { .sq_length = (lenfunc)uop_len, .sq_item = (ssizeargfunc)uop_item, }; PyTypeObject _PyUOpExecutor_Type = { PyVarObject_HEAD_INIT(&PyType_Type, 0) .tp_name = "uop_executor", .tp_basicsize = sizeof(_PyUOpExecutorObject) - sizeof(_PyUOpInstruction), .tp_itemsize = sizeof(_PyUOpInstruction), .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_DISALLOW_INSTANTIATION, .tp_dealloc = (destructor)uop_dealloc, .tp_as_sequence = &uop_as_sequence, .tp_methods = executor_methods, }; static int move_stubs( _PyUOpInstruction *trace, int trace_length, int stubs_start, int stubs_end ) { memmove(trace + trace_length, trace + stubs_start, (stubs_end - stubs_start) * 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) { int target = trace[i].oparg; if (target >= stubs_start) { target += trace_length - stubs_start; trace[i].oparg = target; } } } return trace_length + stubs_end - stubs_start; } #define TRACE_STACK_SIZE 5 static int translate_bytecode_to_trace( PyCodeObject *code, _Py_CODEUNIT *instr, _PyUOpInstruction *trace, int buffer_size, _PyBloomFilter *dependencies) { PyCodeObject *initial_code = code; _Py_BloomFilter_Add(dependencies, initial_code); _Py_CODEUNIT *initial_instr = instr; int trace_length = 0; int max_length = buffer_size; int reserved = 0; struct { PyCodeObject *code; _Py_CODEUNIT *instr; } trace_stack[TRACE_STACK_SIZE]; int trace_stack_depth = 0; #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 #ifdef Py_DEBUG #define DPRINTF(level, ...) \ if (lltrace >= (level)) { printf(__VA_ARGS__); } #else #define DPRINTF(level, ...) #endif #define ADD_TO_TRACE(OPCODE, OPARG, OPERAND) \ DPRINTF(2, \ " ADD_TO_TRACE(%s, %d, %" PRIu64 ")\n", \ uop_name(OPCODE), \ (OPARG), \ (uint64_t)(OPERAND)); \ assert(trace_length < max_length); \ assert(reserved > 0); \ reserved--; \ trace[trace_length].opcode = (OPCODE); \ trace[trace_length].oparg = (OPARG); \ trace[trace_length].operand = (OPERAND); \ trace_length++; #define INSTR_IP(INSTR, CODE) \ ((uint32_t)((INSTR) - ((_Py_CODEUNIT *)(CODE)->co_code_adaptive))) #define ADD_TO_STUB(INDEX, OPCODE, OPARG, OPERAND) \ DPRINTF(2, " ADD_TO_STUB(%d, %s, %d, %" PRIu64 ")\n", \ (INDEX), \ uop_name(OPCODE), \ (OPARG), \ (uint64_t)(OPERAND)); \ assert(reserved > 0); \ reserved--; \ trace[(INDEX)].opcode = (OPCODE); \ trace[(INDEX)].oparg = (OPARG); \ trace[(INDEX)].operand = (OPERAND); // 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; \ } \ reserved = (n); // Keep ADD_TO_TRACE / ADD_TO_STUB honest // Reserve space for main+stub uops, plus 2 for _SET_IP and _EXIT_TRACE #define RESERVE(main, stub) RESERVE_RAW((main) + (stub) + 2, uop_name(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(_SET_IP, 0, 0); \ goto done; \ } \ trace_stack[trace_stack_depth].code = code; \ 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--; \ code = trace_stack[trace_stack_depth].code; \ instr = trace_stack[trace_stack_depth].instr; 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)); top: // Jump here after _PUSH_FRAME or likely branches for (;;) { RESERVE_RAW(2, "epilogue"); // Always need space for _SET_IP and _EXIT_TRACE ADD_TO_TRACE(_SET_IP, INSTR_IP(instr, code), 0); uint32_t opcode = instr->op.code; uint32_t oparg = instr->op.arg; uint32_t 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_NONE: { RESERVE(2, 2); ADD_TO_TRACE(_IS_NONE, 0, 0); opcode = POP_JUMP_IF_TRUE; goto pop_jump_if_bool; } case POP_JUMP_IF_NOT_NONE: { RESERVE(2, 2); ADD_TO_TRACE(_IS_NONE, 0, 0); opcode = POP_JUMP_IF_FALSE; goto pop_jump_if_bool; } case POP_JUMP_IF_FALSE: case POP_JUMP_IF_TRUE: { pop_jump_if_bool: RESERVE(1, 2); max_length -= 2; // Really the start of the stubs int counter = instr[1].cache; int bitcount = _Py_popcount32(counter); bool jump_likely = bitcount > 8; bool jump_sense = opcode == POP_JUMP_IF_TRUE; uint32_t uopcode = jump_sense ^ jump_likely ? _POP_JUMP_IF_TRUE : _POP_JUMP_IF_FALSE; _Py_CODEUNIT *next_instr = instr + 1 + _PyOpcode_Caches[_PyOpcode_Deopt[opcode]]; _Py_CODEUNIT *target_instr = next_instr + oparg; _Py_CODEUNIT *stub_target = jump_likely ? next_instr : target_instr; DPRINTF(4, "%s(%d): counter=%x, bitcount=%d, likely=%d, sense=%d, uopcode=%s\n", uop_name(opcode), oparg, counter, bitcount, jump_likely, jump_sense, uop_name(uopcode)); ADD_TO_TRACE(uopcode, max_length, 0); ADD_TO_STUB(max_length, _SET_IP, INSTR_IP(stub_target, code), 0); ADD_TO_STUB(max_length + 1, _EXIT_TRACE, 0, 0); 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; goto top; } break; } case JUMP_BACKWARD: { if (instr + 2 - oparg == initial_instr && code == initial_code) { RESERVE(1, 0); ADD_TO_TRACE(_JUMP_TO_TOP, 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, 0); // This will emit two _SET_IP instructions; leave it to the optimizer instr += oparg; break; } case FOR_ITER_LIST: case FOR_ITER_TUPLE: case FOR_ITER_RANGE: { RESERVE(4, 3); int check_op, exhausted_op, next_op; switch (opcode) { case FOR_ITER_LIST: check_op = _ITER_CHECK_LIST; exhausted_op = _IS_ITER_EXHAUSTED_LIST; next_op = _ITER_NEXT_LIST; break; case FOR_ITER_TUPLE: check_op = _ITER_CHECK_TUPLE; exhausted_op = _IS_ITER_EXHAUSTED_TUPLE; next_op = _ITER_NEXT_TUPLE; break; case FOR_ITER_RANGE: check_op = _ITER_CHECK_RANGE; exhausted_op = _IS_ITER_EXHAUSTED_RANGE; next_op = _ITER_NEXT_RANGE; break; default: Py_UNREACHABLE(); } // Assume jump unlikely (can a for-loop exit be likely?) _Py_CODEUNIT *target_instr = // +1 at the end skips over END_FOR instr + 1 + _PyOpcode_Caches[_PyOpcode_Deopt[opcode]] + oparg + 1; max_length -= 3; // Really the start of the stubs ADD_TO_TRACE(check_op, 0, 0); ADD_TO_TRACE(exhausted_op, 0, 0); ADD_TO_TRACE(_POP_JUMP_IF_TRUE, max_length, 0); ADD_TO_TRACE(next_op, 0, 0); ADD_TO_STUB(max_length + 0, POP_TOP, 0, 0); ADD_TO_STUB(max_length + 1, _SET_IP, INSTR_IP(target_instr, code), 0); ADD_TO_STUB(max_length + 2, _EXIT_TRACE, 0, 0); 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, 0); 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: if (extras && OPCODE_HAS_JUMP(opcode)) { if (opcode == JUMP_BACKWARD_NO_INTERRUPT) { oparg -= extras; } else { assert(opcode != JUMP_BACKWARD); oparg += 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 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; 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); if (uop == _POP_FRAME) { TRACE_STACK_POP(); 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 *func = _PyFunction_LookupByVersion(func_version); DPRINTF(3, "Function object: %p\n", func); if (func != NULL) { PyCodeObject *new_code = (PyCodeObject *)PyFunction_GET_CODE(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(_SET_IP, 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(_SET_IP, 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); code = new_code; 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(_SET_IP, 0, 0); goto done; } } break; } DPRINTF(2, "Unsupported opcode %s\n", uop_name(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 (trace_length > 3) { ADD_TO_TRACE(_EXIT_TRACE, 0, 0); DPRINTF(1, "Created a trace for %s (%s:%d) at byte offset %d -- length %d+%d\n", PyUnicode_AsUTF8(code->co_qualname), PyUnicode_AsUTF8(code->co_filename), code->co_firstlineno, 2 * INSTR_IP(initial_instr, code), trace_length, buffer_size - max_length); if (max_length < buffer_size) { // There are stubs if (trace_length < max_length) { // There's a gap before the stubs // 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); trace_length = move_stubs(trace, trace_length, max_length, buffer_size); } else { assert(trace_length == max_length); // There's no gap trace_length = buffer_size; } } return trace_length; } else { 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; #undef RESERVE #undef RESERVE_RAW #undef INSTR_IP #undef ADD_TO_TRACE #undef DPRINTF } static int remove_unneeded_uops(_PyUOpInstruction *trace, int trace_length) { // Stage 1: Replace unneeded _SET_IP uops with NOP. // Note that we don't enter stubs, those SET_IPs are needed. int last_set_ip = -1; int last_instr = 0; bool need_ip = true; for (int pc = 0; pc < trace_length; pc++) { int opcode = trace[pc].opcode; if (opcode == _SET_IP) { if (!need_ip && last_set_ip >= 0) { trace[last_set_ip].opcode = NOP; } need_ip = false; last_set_ip = pc; } else if (opcode == _JUMP_TO_TOP || opcode == _EXIT_TRACE) { last_instr = pc + 1; break; } else { // If opcode has ERROR or DEOPT, set need_ip to true if (_PyOpcode_opcode_metadata[opcode].flags & (HAS_ERROR_FLAG | HAS_DEOPT_FLAG) || opcode == _PUSH_FRAME) { need_ip = true; } } } // Stage 2: Squash NOP opcodes (pre-existing or set above). int dest = 0; for (int pc = 0; pc < last_instr; pc++) { int opcode = trace[pc].opcode; if (opcode != NOP) { if (pc != dest) { trace[dest] = trace[pc]; } dest++; } } // Stage 3: Move the stubs back. if (dest < last_instr) { int new_trace_length = move_stubs(trace, dest, last_instr, trace_length); #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 trace (length %d+%d = %d, saved %d):\n", dest, trace_length - last_instr, new_trace_length, trace_length - new_trace_length); for (int pc = 0; pc < new_trace_length; pc++) { printf("%4d: (%s, %d, %" PRIu64 ")\n", pc, uop_name(trace[pc].opcode), (trace[pc].oparg), (uint64_t)(trace[pc].operand)); } } #endif trace_length = new_trace_length; } return trace_length; } static int uop_optimize( _PyOptimizerObject *self, PyCodeObject *code, _Py_CODEUNIT *instr, _PyExecutorObject **exec_ptr, int curr_stackentries) { _PyBloomFilter dependencies; _Py_BloomFilter_Init(&dependencies); _PyUOpInstruction trace[_Py_UOP_MAX_TRACE_LENGTH]; int trace_length = translate_bytecode_to_trace(code, instr, trace, _Py_UOP_MAX_TRACE_LENGTH, &dependencies); if (trace_length <= 0) { // Error or nothing translated return trace_length; } OPT_HIST(trace_length, trace_length_hist); OPT_STAT_INC(traces_created); char *uop_optimize = Py_GETENV("PYTHONUOPSOPTIMIZE"); if (uop_optimize != NULL && *uop_optimize > '0') { trace_length = _Py_uop_analyze_and_optimize(code, trace, trace_length, curr_stackentries); } trace_length = remove_unneeded_uops(trace, trace_length); _PyUOpExecutorObject *executor = PyObject_NewVar(_PyUOpExecutorObject, &_PyUOpExecutor_Type, trace_length); if (executor == NULL) { return -1; } OPT_HIST(trace_length, optimized_trace_length_hist); executor->base.execute = _PyUopExecute; memcpy(executor->trace, trace, trace_length * sizeof(_PyUOpInstruction)); _Py_ExecutorInit((_PyExecutorObject *)executor, &dependencies); *exec_ptr = (_PyExecutorObject *)executor; return 1; } /* Dummy execute() function for Uop Executor. * The actual implementation is inlined in ceval.c, * in _PyEval_EvalFrameDefault(). */ _PyInterpreterFrame * _PyUopExecute(_PyExecutorObject *executor, _PyInterpreterFrame *frame, PyObject **stack_pointer) { Py_FatalError("Tier 2 is now inlined into Tier 1"); } static void uop_opt_dealloc(PyObject *self) { PyObject_Free(self); } PyTypeObject _PyUOpOptimizer_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, &_PyUOpOptimizer_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 = 16 << OPTIMIZER_BITS_IN_COUNTER; return (PyObject *)opt; } /***************************************** * Executor management ****************************************/ /* We use a bloomfilter with k = 6, m = 256 * The choice of k and the following constants * could do with a more rigourous analysis, * but here is a simple analysis: * * We want to keep the false positive rate low. * For n = 5 (a trace depends on 5 objects), * we expect 30 bits set, giving a false positive * rate of (30/256)**6 == 2.5e-6 which is plenty * good enough. * * However with n = 10 we expect 60 bits set (worst case), * giving a false positive of (60/256)**6 == 0.0001 * * We choose k = 6, rather than a higher number as * it means the false positive rate grows slower for high n. * * n = 5, k = 6 => fp = 2.6e-6 * n = 5, k = 8 => fp = 3.5e-7 * n = 10, k = 6 => fp = 1.6e-4 * n = 10, k = 8 => fp = 0.9e-4 * n = 15, k = 6 => fp = 0.18% * n = 15, k = 8 => fp = 0.23% * n = 20, k = 6 => fp = 1.1% * n = 20, k = 8 => fp = 2.3% * * The above analysis assumes perfect hash functions, * but those don't exist, so the real false positive * rates may be worse. */ #define K 6 #define SEED 20221211 /* TO DO -- Use more modern hash functions with better distribution of bits */ static uint64_t address_to_hash(void *ptr) { assert(ptr != NULL); uint64_t uhash = SEED; uintptr_t addr = (uintptr_t)ptr; for (int i = 0; i < SIZEOF_VOID_P; i++) { uhash ^= addr & 255; uhash *= (uint64_t)_PyHASH_MULTIPLIER; addr >>= 8; } return uhash; } void _Py_BloomFilter_Init(_PyBloomFilter *bloom) { for (int i = 0; i < BLOOM_FILTER_WORDS; i++) { bloom->bits[i] = 0; } } /* We want K hash functions that each set 1 bit. * A hash function that sets 1 bit in M bits can be trivially * derived from a log2(M) bit hash function. * So we extract 8 (log2(256)) bits at a time from * the 64bit hash. */ void _Py_BloomFilter_Add(_PyBloomFilter *bloom, void *ptr) { uint64_t hash = address_to_hash(ptr); assert(K <= 8); for (int i = 0; i < K; i++) { uint8_t bits = hash & 255; bloom->bits[bits >> 5] |= (1 << (bits&31)); hash >>= 8; } } static bool bloom_filter_may_contain(_PyBloomFilter *bloom, _PyBloomFilter *hashes) { for (int i = 0; i < BLOOM_FILTER_WORDS; i++) { if ((bloom->bits[i] & hashes->bits[i]) != hashes->bits[i]) { return false; } } return true; } static void link_executor(_PyExecutorObject *executor) { PyInterpreterState *interp = _PyInterpreterState_GET(); _PyExecutorLinkListNode *links = &executor->vm_data.links; _PyExecutorObject *head = interp->executor_list_head; if (head == NULL) { interp->executor_list_head = executor; links->previous = NULL; links->next = NULL; } else { _PyExecutorObject *next = head->vm_data.links.next; links->previous = head; links->next = next; if (next != NULL) { next->vm_data.links.previous = executor; } head->vm_data.links.next = executor; } executor->vm_data.linked = true; /* executor_list_head must be first in list */ assert(interp->executor_list_head->vm_data.links.previous == NULL); } static void unlink_executor(_PyExecutorObject *executor) { if (!executor->vm_data.linked) { return; } _PyExecutorLinkListNode *links = &executor->vm_data.links; _PyExecutorObject *next = links->next; _PyExecutorObject *prev = links->previous; if (next != NULL) { next->vm_data.links.previous = prev; } if (prev != NULL) { prev->vm_data.links.next = next; } else { // prev == NULL implies that executor is the list head PyInterpreterState *interp = PyInterpreterState_Get(); assert(interp->executor_list_head == executor); interp->executor_list_head = next; } executor->vm_data.linked = false; } /* This must be called by optimizers before using the executor */ void _Py_ExecutorInit(_PyExecutorObject *executor, _PyBloomFilter *dependency_set) { executor->vm_data.valid = true; for (int i = 0; i < BLOOM_FILTER_WORDS; i++) { executor->vm_data.bloom.bits[i] = dependency_set->bits[i]; } link_executor(executor); } /* This must be called by executors during dealloc */ void _Py_ExecutorClear(_PyExecutorObject *executor) { unlink_executor(executor); } void _Py_Executor_DependsOn(_PyExecutorObject *executor, void *obj) { assert(executor->vm_data.valid = true); _Py_BloomFilter_Add(&executor->vm_data.bloom, obj); } /* Invalidate all executors that depend on `obj` * May cause other executors to be invalidated as well */ void _Py_Executors_InvalidateDependency(PyInterpreterState *interp, void *obj) { _PyBloomFilter obj_filter; _Py_BloomFilter_Init(&obj_filter); _Py_BloomFilter_Add(&obj_filter, obj); /* Walk the list of executors */ /* TO DO -- Use a tree to avoid traversing as many objects */ for (_PyExecutorObject *exec = interp->executor_list_head; exec != NULL;) { assert(exec->vm_data.valid); _PyExecutorObject *next = exec->vm_data.links.next; if (bloom_filter_may_contain(&exec->vm_data.bloom, &obj_filter)) { exec->vm_data.valid = false; unlink_executor(exec); } exec = next; } } /* Invalidate all executors */ void _Py_Executors_InvalidateAll(PyInterpreterState *interp) { /* Walk the list of executors */ for (_PyExecutorObject *exec = interp->executor_list_head; exec != NULL;) { assert(exec->vm_data.valid); _PyExecutorObject *next = exec->vm_data.links.next; exec->vm_data.links.next = NULL; exec->vm_data.links.previous = NULL; exec->vm_data.valid = false; exec->vm_data.linked = false; exec = next; } interp->executor_list_head = NULL; }