| #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, |
| int curr_stackentries) |
| { |
| _PyBloomFilter dependencies; |
| _Py_BloomFilter_Init(&dependencies); |
| _PyUOpInstruction buffer[UOP_MAX_TRACE_LENGTH]; |
| OPT_STAT_INC(attempts); |
| int err = translate_bytecode_to_trace(frame, instr, buffer, UOP_MAX_TRACE_LENGTH, &dependencies); |
| if (err <= 0) { |
| // Error or nothing translated |
| return err; |
| } |
| OPT_STAT_INC(traces_created); |
| char *env_var = Py_GETENV("PYTHON_UOPS_OPTIMIZE"); |
| if (env_var == NULL || *env_var == '\0' || *env_var > '0') { |
| err = _Py_uop_analyze_and_optimize(frame, buffer, |
| UOP_MAX_TRACE_LENGTH, |
| curr_stackentries, &dependencies); |
| if (err <= 0) { |
| return err; |
| } |
| } |
| assert(err == 1); |
| /* Fix up */ |
| for (int pc = 0; pc < UOP_MAX_TRACE_LENGTH; pc++) { |
| int opcode = buffer[pc].opcode; |
| int oparg = buffer[pc].oparg; |
| if (_PyUop_Flags[opcode] & HAS_OPARG_AND_1_FLAG) { |
| buffer[pc].opcode = opcode + 1 + (oparg & 1); |
| } |
| else if (oparg < _PyUop_Replication[opcode]) { |
| buffer[pc].opcode = opcode + oparg + 1; |
| } |
| else if (opcode == _JUMP_TO_TOP || opcode == _EXIT_TRACE) { |
| break; |
| } |
| assert(_PyOpcode_uop_name[buffer[pc].opcode]); |
| assert(strncmp(_PyOpcode_uop_name[buffer[pc].opcode], _PyOpcode_uop_name[opcode], strlen(_PyOpcode_uop_name[opcode])) == 0); |
| } |
| _PyExecutorObject *executor = make_executor_from_uops(buffer, &dependencies); |
| if (executor == NULL) { |
| return -1; |
| } |
| OPT_HIST(Py_SIZE(executor), optimized_trace_length_hist); |
| *exec_ptr = executor; |
| return 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 = OPTIMIZER_UNREACHABLE_THRESHOLD; |
| // Need a few iterations to settle specializations, |
| // and to ammortize the cost of optimization. |
| opt->side_threshold = 16; |
| opt->backedge_threshold = 16; |
| return (PyObject *)opt; |
| } |
| |
| static void |
| counter_dealloc(_PyExecutorObject *self) { |
| /* The optimizer is the operand of the second uop. */ |
| PyObject *opt = (PyObject *)self->trace[1].operand; |
| Py_DECREF(opt); |
| uop_dealloc(self); |
| } |
| |
| PyTypeObject _PyCounterExecutor_Type = { |
| PyVarObject_HEAD_INIT(&PyType_Type, 0) |
| .tp_name = "counting_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)counter_dealloc, |
| .tp_methods = executor_methods, |
| .tp_traverse = executor_traverse, |
| .tp_clear = executor_clear, |
| }; |
| |
| static int |
| counter_optimize( |
| _PyOptimizerObject* self, |
| _PyInterpreterFrame *frame, |
| _Py_CODEUNIT *instr, |
| _PyExecutorObject **exec_ptr, |
| int Py_UNUSED(curr_stackentries) |
| ) |
| { |
| PyCodeObject *code = (PyCodeObject *)frame->f_executable; |
| int oparg = instr->op.arg; |
| while (instr->op.code == EXTENDED_ARG) { |
| instr++; |
| oparg = (oparg << 8) | instr->op.arg; |
| } |
| if (instr->op.code != JUMP_BACKWARD) { |
| /* Counter optimizer can only handle backward edges */ |
| return 0; |
| } |
| _Py_CODEUNIT *target = instr + 1 + _PyOpcode_Caches[JUMP_BACKWARD] - oparg; |
| _PyUOpInstruction buffer[3] = { |
| { .opcode = _LOAD_CONST_INLINE_BORROW, .operand = (uintptr_t)self }, |
| { .opcode = _INTERNAL_INCREMENT_OPT_COUNTER }, |
| { .opcode = _EXIT_TRACE, .target = (uint32_t)(target - _PyCode_CODE(code)) } |
| }; |
| _PyExecutorObject *executor = make_executor_from_uops(buffer, &EMPTY_FILTER); |
| if (executor == NULL) { |
| return -1; |
| } |
| Py_INCREF(self); |
| Py_SET_TYPE(executor, &_PyCounterExecutor_Type); |
| *exec_ptr = executor; |
| 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 = OPTIMIZER_UNREACHABLE_THRESHOLD; |
| opt->base.side_threshold = OPTIMIZER_UNREACHABLE_THRESHOLD; |
| opt->base.backedge_threshold = 0; |
| opt->count = 0; |
| 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.valid = 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) |
| { |
| _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.valid = false; |
| } |
| |
| /* This must be called by optimizers before using the executor */ |
| void |
| _Py_ExecutorInit(_PyExecutorObject *executor, const _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) |
| { |
| if (!executor->vm_data.valid) { |
| return; |
| } |
| unlink_executor(executor); |
| PyCodeObject *code = executor->vm_data.code; |
| if (code == NULL) { |
| return; |
| } |
| for (uint32_t i = 0; i < executor->exit_count; i++) { |
| Py_DECREF(executor->exits[i].executor); |
| executor->exits[i].executor = &COLD_EXITS[i]; |
| executor->exits[i].temperature = INT16_MIN; |
| } |
| _Py_CODEUNIT *instruction = &_PyCode_CODE(code)[executor->vm_data.index]; |
| assert(instruction->op.code == ENTER_EXECUTOR); |
| int index = instruction->op.arg; |
| assert(code->co_executors->executors[index] == executor); |
| instruction->op.code = executor->vm_data.opcode; |
| instruction->op.arg = executor->vm_data.oparg; |
| executor->vm_data.code = NULL; |
| Py_CLEAR(code->co_executors->executors[index]); |
| } |
| |
| void |
| _Py_Executor_DependsOn(_PyExecutorObject *executor, void *obj) |
| { |
| assert(executor->vm_data.valid); |
| _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, int is_invalidation) |
| { |
| _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)) { |
| _Py_ExecutorClear(exec); |
| if (is_invalidation) { |
| OPT_STAT_INC(executors_invalidated); |
| } |
| } |
| exec = next; |
| } |
| } |
| |
| /* Invalidate all executors */ |
| void |
| _Py_Executors_InvalidateAll(PyInterpreterState *interp, int is_invalidation) |
| { |
| while (interp->executor_list_head) { |
| _PyExecutorObject *executor = interp->executor_list_head; |
| if (executor->vm_data.code) { |
| // Clear the entire code object so its co_executors array be freed: |
| _PyCode_Clear_Executors(executor->vm_data.code); |
| } |
| else { |
| _Py_ExecutorClear(executor); |
| } |
| if (is_invalidation) { |
| OPT_STAT_INC(executors_invalidated); |
| } |
| } |
| } |