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GeezerVison is showing github.com — cpython/Python/optimizer_analysis.c at main · python/cpython Expand file tree/ Copy pathoptimizer_analysis.cMore file actions 832 lines (758 loc) · 26.4 KB / Copy pathoptimizer_analysis.cFile metadata and controls832 lines (758 loc) · 26.4 KB 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 #ifdef _Py_TIER2 /* * This file contains the support code for CPython's uops optimizer. * It also performs some simple optimizations. * It performs a traditional data-flow analysis[1] over the trace of uops. * Using the information gained, it chooses to emit, or skip certain instructions * if possible. * * [1] For information on data-flow analysis, please see * https://clang.llvm.org/docs/DataFlowAnalysisIntro.html * * */ #include "Python.h" #include "opcode.h" #include "pycore_call.h" // _Py_METH_CALL_FLAGS #include "pycore_dict.h" #include "pycore_interp.h" #include "pycore_opcode_metadata.h" #include "pycore_opcode_utils.h" #include "pycore_pystate.h" // _PyInterpreterState_GET() #include "pycore_pyatomic_ft_wrappers.h" // FT_ATOMIC_* #include "pycore_tstate.h" // _PyThreadStateImpl #include "pycore_uop_metadata.h" #include "pycore_long.h" #include "pycore_interpframe.h" // _PyFrame_GetCode #include "pycore_optimizer.h" #include "pycore_object.h" #include "pycore_function.h" #include "pycore_uop_ids.h" #include "pycore_range.h" #include "pycore_unicodeobject.h" #include "pycore_ceval.h" #include "pycore_floatobject.h" #include "pycore_setobject.h" #include "pycore_typeobject.h" #include <stdarg.h> #include <stdbool.h> #include <stdint.h> #include <stddef.h> #ifdef Py_DEBUG extern const char *_PyUOpName(int index); extern void _PyUOpPrint(const _PyUOpInstruction *uop); extern void _PyUOpSymPrint(JitOptRef ref); static const char *const DEBUG_ENV = "PYTHON_OPT_DEBUG"; static inline int get_lltrace(void) { char *uop_debug = Py_GETENV(DEBUG_ENV); int lltrace = 0; if (uop_debug != NULL && *uop_debug >= '0') { lltrace = *uop_debug - '0'; // TODO: Parse an int and all that } return lltrace; } #define DPRINTF(level, ...) \ if (get_lltrace() >= (level)) { printf(__VA_ARGS__); } static void dump_abstract_stack(_Py_UOpsAbstractFrame *frame, JitOptRef *stack_pointer) { printf(" locals=["); for (int i = 0 ; i < frame->locals_len; i++) { if (i > 0) { printf(", "); } _PyUOpSymPrint(frame->locals[i]); } printf("]\n"); if (stack_pointer < frame->stack) { printf(" stack=%d\n", (int)(stack_pointer - frame->stack)); } else { printf(" stack=["); for (JitOptRef *ptr = frame->stack; ptr < stack_pointer; ptr++) { if (ptr != frame->stack) { printf(", "); } _PyUOpSymPrint(*ptr); } printf("]\n"); } fflush(stdout); } static void dump_uop(JitOptContext *ctx, const char *label, int index, const _PyUOpInstruction *instr, JitOptRef *stack_pointer) { if (get_lltrace() >= 3) { printf("%4d %s: ", index, label); _PyUOpPrint(instr); printf("\n"); if (get_lltrace() >= 5 && ctx->frame->code != ((PyCodeObject *)&_Py_InitCleanup)) { dump_abstract_stack(ctx->frame, stack_pointer); } } } static void dump_uops(JitOptContext *ctx, const char *label, _PyUOpInstruction *start, JitOptRef *stack_pointer) { int current_len = uop_buffer_length(&ctx->out_buffer); int added_count = (int)(ctx->out_buffer.next - start); for (int j = 0; j < added_count; j++) { dump_uop(ctx, label, current_len - added_count + j, &start[j], stack_pointer); } } #define DUMP_UOP dump_uop #define DUMP_UOPS dump_uops #else #define DPRINTF(level, ...) #define DUMP_UOP(ctx, label, index, instr, stack_pointer) #define DUMP_UOPS(ctx, label, start, stack_pointer) #endif static int get_mutations(PyObject* dict) { assert(PyDict_CheckExact(dict)); PyDictObject *d = (PyDictObject *)dict; uint64_t tag = FT_ATOMIC_LOAD_UINT64_RELAXED(d->_ma_watcher_tag); return (tag >> DICT_MAX_WATCHERS) & ((1 << DICT_WATCHED_MUTATION_BITS) - 1); } static void increment_mutations(PyObject* dict) { assert(PyDict_CheckExact(dict)); PyDictObject *d = (PyDictObject *)dict; FT_ATOMIC_ADD_UINT64(d->_ma_watcher_tag, 1ULL << DICT_MAX_WATCHERS); } /* The first two dict watcher IDs are reserved for CPython, * so we don't need to check that they haven't been used */ #define BUILTINS_WATCHER_ID 0 #define GLOBALS_WATCHER_ID 1 #define TYPE_WATCHER_ID 0 static int globals_watcher_callback(PyDict_WatchEvent event, PyObject* dict, PyObject* key, PyObject* new_value) { RARE_EVENT_STAT_INC(watched_globals_modification); assert(get_mutations(dict) < _Py_MAX_ALLOWED_GLOBALS_MODIFICATIONS); _Py_Executors_InvalidateDependency(_PyInterpreterState_GET(), dict, 1); increment_mutations(dict); PyDict_Unwatch(GLOBALS_WATCHER_ID, dict); return 0; } static int type_watcher_callback(PyTypeObject* type) { _Py_Executors_InvalidateDependency(_PyInterpreterState_GET(), type, 1); PyType_Unwatch(TYPE_WATCHER_ID, (PyObject *)type); return 0; } static int _setup_optimizer_watchers(void *Py_UNUSED(arg)) { PyInterpreterState *interp = _PyInterpreterState_GET(); FT_ATOMIC_STORE_PTR_RELEASE( interp->dict_state.watchers[GLOBALS_WATCHER_ID], globals_watcher_callback); interp->type_watchers[TYPE_WATCHER_ID] = type_watcher_callback; return 0; } static void watch_type(PyTypeObject *type, _PyBloomFilter *filter) { if (_Py_IsImmortal(type) && (type->tp_flags & Py_TPFLAGS_IMMUTABLETYPE)) { return; } PyType_Watch(TYPE_WATCHER_ID, (PyObject *)type); _Py_BloomFilter_Add(filter, type); } static PyObject * convert_global_to_const(_PyUOpInstruction *inst, PyObject *obj) { assert(inst->opcode == _LOAD_GLOBAL_MODULE || inst->opcode == _LOAD_GLOBAL_BUILTINS || inst->opcode == _LOAD_ATTR_MODULE); assert(PyDict_CheckExact(obj)); PyDictObject *dict = (PyDictObject *)obj; assert(dict->ma_keys->dk_kind == DICT_KEYS_UNICODE); PyDictUnicodeEntry *entries = DK_UNICODE_ENTRIES(dict->ma_keys); int64_t index = inst->operand1; assert(index <= UINT16_MAX); if ((int)index >= dict->ma_keys->dk_nentries) { return NULL; } PyDictKeysObject *keys = dict->ma_keys; if (keys->dk_version != inst->operand0) { return NULL; } PyObject *res = entries[index].me_value; if (res == NULL) { return NULL; } if (_Py_IsImmortal(res)) { inst->opcode = _LOAD_CONST_INLINE_BORROW; } else { inst->opcode = _LOAD_CONST_INLINE; } inst->operand0 = (uint64_t)res; return res; } static bool incorrect_keys(PyObject *obj, uint32_t version) { if (!PyDict_CheckExact(obj)) { return true; } PyDictObject *dict = (PyDictObject *)obj; return dict->ma_keys->dk_version != version; } #define STACK_LEVEL() ((int)(stack_pointer - ctx->frame->stack)) #define STACK_SIZE() ((int)(ctx->frame->stack_len)) static inline int is_terminator_uop(const _PyUOpInstruction *uop) { int opcode = uop->opcode; return ( opcode == _EXIT_TRACE || opcode == _JUMP_TO_TOP || opcode == _DYNAMIC_EXIT || opcode == _DEOPT ); } #define CURRENT_FRAME_IS_INIT_SHIM() (ctx->frame->code == ((PyCodeObject *)&_Py_InitCleanup)) #define GETLOCAL(idx) ((ctx->frame->locals[idx])) #define REPLACE_OP(INST, OP, ARG, OPERAND) \ (INST)->opcode = OP; \ (INST)->oparg = ARG; \ (INST)->operand0 = OPERAND; #define ADD_OP(OP, ARG, OPERAND) add_op(ctx, this_instr, (OP), (ARG), (OPERAND)) static inline void add_op(JitOptContext *ctx, _PyUOpInstruction *this_instr, uint16_t opcode, uint16_t oparg, uintptr_t operand0) { _PyUOpInstruction *out = ctx->out_buffer.next; assert(out < ctx->out_buffer.end); out->opcode = (opcode); out->format = this_instr->format; out->oparg = (oparg); out->target = this_instr->target; out->operand0 = (operand0); out->operand1 = this_instr->operand1; #ifdef Py_STATS out->fitness = this_instr->fitness; #endif ctx->out_buffer.next++; } /* Shortened forms for convenience, used in optimizer_bytecodes.c */ #define sym_is_not_null _Py_uop_sym_is_not_null #define sym_is_const _Py_uop_sym_is_const #define sym_is_safe_const _Py_uop_sym_is_safe_const #define sym_is_not_container _Py_uop_sym_is_not_container #define sym_get_const _Py_uop_sym_get_const #define sym_new_const_steal _Py_uop_sym_new_const_steal #define sym_get_const_as_stackref _Py_uop_sym_get_const_as_stackref #define sym_new_unknown _Py_uop_sym_new_unknown #define sym_new_not_null _Py_uop_sym_new_not_null #define sym_new_type _Py_uop_sym_new_type #define sym_is_null _Py_uop_sym_is_null #define sym_new_const _Py_uop_sym_new_const #define sym_new_null _Py_uop_sym_new_null #define sym_has_type _Py_uop_sym_has_type #define sym_get_type _Py_uop_sym_get_type #define sym_get_probable_type _Py_uop_sym_get_probable_type #define sym_matches_type _Py_uop_sym_matches_type #define sym_matches_type_version _Py_uop_sym_matches_type_version #define sym_get_type_version _Py_uop_sym_get_type_version #define sym_set_null(SYM) _Py_uop_sym_set_null(ctx, SYM) #define sym_set_non_null(SYM) _Py_uop_sym_set_non_null(ctx, SYM) #define sym_set_type(SYM, TYPE) _Py_uop_sym_set_type(ctx, SYM, TYPE) #define sym_set_type_version(SYM, VERSION) _Py_uop_sym_set_type_version(ctx, SYM, VERSION) #define sym_set_const(SYM, CNST) _Py_uop_sym_set_const(ctx, SYM, CNST) #define sym_set_compact_int(SYM) _Py_uop_sym_set_compact_int(ctx, SYM) #define sym_is_bottom _Py_uop_sym_is_bottom #define sym_truthiness _Py_uop_sym_truthiness #define frame_new _Py_uop_frame_new #define frame_new_from_symbol _Py_uop_frame_new_from_symbol #define frame_pop _Py_uop_frame_pop #define sym_new_tuple _Py_uop_sym_new_tuple #define sym_tuple_getitem _Py_uop_sym_tuple_getitem #define sym_tuple_length _Py_uop_sym_tuple_length #define sym_is_immortal _Py_uop_symbol_is_immortal #define sym_is_compact_int _Py_uop_sym_is_compact_int #define sym_new_compact_int _Py_uop_sym_new_compact_int #define sym_new_truthiness _Py_uop_sym_new_truthiness #define sym_new_predicate _Py_uop_sym_new_predicate #define sym_apply_predicate_narrowing _Py_uop_sym_apply_predicate_narrowing #define sym_set_recorded_type(SYM, TYPE) _Py_uop_sym_set_recorded_type(ctx, SYM, TYPE) #define sym_set_recorded_value(SYM, VAL) _Py_uop_sym_set_recorded_value(ctx, SYM, VAL) #define sym_set_recorded_gen_func(SYM, VAL) _Py_uop_sym_set_recorded_gen_func(ctx, SYM, VAL) #define sym_get_probable_func_code _Py_uop_sym_get_probable_func_code #define sym_get_probable_value _Py_uop_sym_get_probable_value #define sym_set_stack_depth(DEPTH, SP) _Py_uop_sym_set_stack_depth(ctx, DEPTH, SP) /* Comparison oparg masks */ #define COMPARE_LT_MASK 2 #define COMPARE_GT_MASK 4 #define COMPARE_EQ_MASK 8 #define JUMP_TO_LABEL(label) goto label; static int check_stack_bounds(JitOptContext *ctx, JitOptRef *stack_pointer, int offset, int opcode) { int stack_level = (int)(stack_pointer + (offset) - ctx->frame->stack); int should_check = !CURRENT_FRAME_IS_INIT_SHIM() || (opcode == _RETURN_VALUE) || (opcode == _RETURN_GENERATOR) || (opcode == _YIELD_VALUE); if (should_check && (stack_level < 0 || stack_level > STACK_SIZE() + MAX_CACHED_REGISTER)) { ctx->contradiction = true; ctx->done = true; return 1; } return 0; } #define CHECK_STACK_BOUNDS(offset) \ if (check_stack_bounds(ctx, stack_pointer, offset, opcode)) { \ break; \ } \ static int optimize_to_bool( _PyUOpInstruction *this_instr, JitOptContext *ctx, JitOptRef value, JitOptRef *result_ptr, uint16_t prefix, uint16_t suffix) { if (sym_matches_type(value, &PyBool_Type)) { ADD_OP(_NOP, 0, 0); *result_ptr = value; return 1; } int truthiness = sym_truthiness(ctx, value); if (truthiness >= 0) { PyObject *load = truthiness ? Py_True : Py_False; if (prefix != _NOP) { ADD_OP(prefix, 0, 0); } ADD_OP(_LOAD_CONST_INLINE_BORROW, 0, (uintptr_t)load); if (suffix != _NOP) { ADD_OP(suffix, 2, 0); } *result_ptr = sym_new_const(ctx, load); return 1; } return 0; } static void optimize_dict_known_hash( JitOptContext *ctx, _PyBloomFilter *dependencies, _PyUOpInstruction *this_instr, PyObject *sub, uint16_t opcode) { if (PyUnicode_CheckExact(sub) || PyLong_CheckExact(sub) || PyBytes_CheckExact(sub) || PyFloat_CheckExact(sub) || PyComplex_CheckExact(sub)) { // PyObject_Hash can't fail on these types ADD_OP(opcode, 0, PyObject_Hash(sub)); } else if (PyTuple_CheckExact(sub)) { // only use known hash variant when hash of tuple is already computed // since computing it can call arbitrary code Py_hash_t hash = ((PyTupleObject *)sub)->ob_hash; if (hash != -1) { ADD_OP(opcode, 0, hash); } } else if (Py_TYPE(sub)->tp_hash == PyBaseObject_Type.tp_hash) { // for user-defined objects which don't override tp_hash Py_hash_t hash = PyObject_Hash(sub); ADD_OP(opcode, 0, hash); watch_type(Py_TYPE(sub), dependencies); } } static void eliminate_pop_guard(_PyUOpInstruction *this_instr, JitOptContext *ctx, bool exit) { ADD_OP(_POP_TOP, 0, 0); if (exit) { REPLACE_OP((this_instr+1), _EXIT_TRACE, 0, 0); this_instr[1].target = this_instr->target; } } static JitOptRef lookup_attr(JitOptContext *ctx, _PyBloomFilter *dependencies, _PyUOpInstruction *this_instr, PyTypeObject *type, PyObject *name, uint16_t prefix, uint16_t suffix) { // The cached value may be dead, so we need to do the lookup again... :( if (type && PyType_Check(type)) { PyObject *lookup = _PyType_Lookup(type, name); if (lookup) { bool immortal = _Py_IsImmortal(lookup) || (type->tp_flags & Py_TPFLAGS_IMMUTABLETYPE); if (prefix != _NOP) { ADD_OP(prefix, 0, 0); } ADD_OP(immortal ? _LOAD_CONST_INLINE_BORROW : _LOAD_CONST_INLINE, 0, (uintptr_t)lookup); if (suffix != _NOP) { ADD_OP(suffix, 2, 0); } if ((type->tp_flags & Py_TPFLAGS_IMMUTABLETYPE) == 0) { watch_type(type, dependencies); } return sym_new_const(ctx, lookup); } } return sym_new_not_null(ctx); } static void optimize_pop_top(JitOptContext *ctx, _PyUOpInstruction *this_instr, JitOptRef value) { PyTypeObject *typ = sym_get_type(value); if (PyJitRef_IsBorrowed(value) || sym_is_immortal(PyJitRef_Unwrap(value)) || sym_is_null(value)) { ADD_OP(_POP_TOP_NOP, 0, 0); } else if (typ == &PyLong_Type) { ADD_OP(_POP_TOP_INT, 0, 0); } else if (typ == &PyFloat_Type) { ADD_OP(_POP_TOP_FLOAT, 0, 0); } else if (typ == &PyUnicode_Type) { ADD_OP(_POP_TOP_UNICODE, 0, 0); } else { ADD_OP(_POP_TOP, 0, 0); } } /* Look up name via super (normal case from supercheck where su_obj_type = Py_TYPE(obj)). */ static JitOptRef lookup_super_attr(JitOptContext *ctx, _PyBloomFilter *dependencies, _PyUOpInstruction *this_instr, PyTypeObject *su_type, PyTypeObject *obj_type, PyObject *name, uint16_t immortal, uint16_t mortal, uint16_t suffix) { if (su_type == NULL || obj_type == NULL) { return sym_new_not_null(ctx); } /* Normal case: obj_type must be a subtype of su_type */ if (!PyType_IsSubtype(obj_type, su_type)) { return sym_new_not_null(ctx); } PyObject *lookup = _PySuper_LookupDescr(su_type, obj_type, name); if (lookup == NULL) { if (PyErr_Occurred()) { PyErr_Clear(); } return sym_new_not_null(ctx); } if ((Py_TYPE(lookup)->tp_flags & Py_TPFLAGS_METHOD_DESCRIPTOR) == 0) { Py_DECREF(lookup); return sym_new_not_null(ctx); } int opcode = mortal; if (_Py_IsImmortal(lookup) || (obj_type->tp_flags & Py_TPFLAGS_IMMUTABLETYPE)) { opcode = immortal; } ADD_OP(_SWAP, 3, 0); ADD_OP(_POP_TOP, 0, 0); ADD_OP(_POP_TOP, 0, 0); ADD_OP(opcode, 0, (uintptr_t)lookup); if (suffix != _NOP) { ADD_OP(suffix, 2, 0); } // if obj_type is immutable, then all its superclasses are immutable if ((obj_type->tp_flags & Py_TPFLAGS_IMMUTABLETYPE) == 0) { watch_type(su_type, dependencies); watch_type(obj_type, dependencies); } return sym_new_const_steal(ctx, lookup); } static PyCodeObject * get_current_code_object(JitOptContext *ctx) { return (PyCodeObject *)ctx->frame->code; } static PyObject * get_co_name(JitOptContext *ctx, int index) { return PyTuple_GET_ITEM(get_current_code_object(ctx)->co_names, index); } static int get_test_bit_for_bools(void) { #ifdef Py_STACKREF_DEBUG uintptr_t false_bits = _Py_STACKREF_FALSE_INDEX; uintptr_t true_bits = _Py_STACKREF_TRUE_INDEX; #else uintptr_t false_bits = (uintptr_t)&_Py_FalseStruct; uintptr_t true_bits = (uintptr_t)&_Py_TrueStruct; #endif for (int i = 4; i < 8; i++) { if ((true_bits ^ false_bits) & (uintptr_t)(1 << i)) { return i; } } return 0; } static int test_bit_set_in_true(int bit) { #ifdef Py_STACKREF_DEBUG uintptr_t true_bits = _Py_STACKREF_TRUE_INDEX; #else uintptr_t true_bits = (uintptr_t)&_Py_TrueStruct; #endif assert((true_bits ^ ((uintptr_t)&_Py_FalseStruct)) & (uintptr_t)(1 << bit)); return true_bits & (uintptr_t)(1 << bit); } #ifdef Py_DEBUG void _Py_opt_assert_within_stack_bounds( _Py_UOpsAbstractFrame *frame, JitOptRef *stack_pointer, const char *filename, int lineno ) { if (frame->code == ((PyCodeObject *)&_Py_InitCleanup)) { return; } int level = (int)(stack_pointer - frame->stack); if (level < 0) { printf("Stack underflow (depth = %d) at %s:%d\n", level, filename, lineno); fflush(stdout); abort(); } int size = (int)(frame->stack_len) + MAX_CACHED_REGISTER; if (level > size) { printf("Stack overflow (depth = %d) at %s:%d\n", level, filename, lineno); fflush(stdout); abort(); } } #endif #ifdef Py_DEBUG #define ASSERT_WITHIN_STACK_BOUNDS(F, L) _Py_opt_assert_within_stack_bounds(ctx->frame, stack_pointer, (F), (L)) #else #define ASSERT_WITHIN_STACK_BOUNDS(F, L) (void)0 #endif /* >0 (length) for success, 0 for not ready, clears all possible errors. */ static int optimize_uops( _PyThreadStateImpl *tstate, _PyUOpInstruction *trace, int trace_len, int curr_stacklen, _PyUOpInstruction *output, _PyBloomFilter *dependencies ) { assert(!PyErr_Occurred()); assert(tstate->jit_tracer_state != NULL); PyFunctionObject *func = tstate->jit_tracer_state->initial_state.func; JitOptContext *ctx = &tstate->jit_tracer_state->opt_context; uint32_t opcode = UINT16_MAX; uop_buffer_init(&ctx->out_buffer, output, UOP_MAX_TRACE_LENGTH); // Make sure that watchers are set up PyInterpreterState *interp = _PyInterpreterState_GET(); _PyOnceFlag_CallOnce(&interp->dict_state.watcher_setup_once, _setup_optimizer_watchers, NULL); _Py_uop_abstractcontext_init(ctx, dependencies); _Py_UOpsAbstractFrame *frame = _Py_uop_frame_new(ctx, (PyCodeObject *)func->func_code, NULL, 0); if (frame == NULL) { return 0; } frame->func = func; ctx->curr_frame_depth++; ctx->frame = frame; _Py_uop_sym_set_stack_depth(ctx, curr_stacklen, frame->stack_pointer); _PyUOpInstruction *this_instr = NULL; JitOptRef *stack_pointer = ctx->frame->stack_pointer; for (int i = 0; i < trace_len; i++) { this_instr = &trace[i]; if (ctx->done) { // Don't do any more optimization, but // we still need to reach a terminator for corrctness. *(ctx->out_buffer.next++) = *this_instr; if (is_terminator_uop(this_instr)) { break; } continue; } int oparg = this_instr->oparg; opcode = this_instr->opcode; if (!CURRENT_FRAME_IS_INIT_SHIM()) { stack_pointer = ctx->frame->stack_pointer; } DUMP_UOP(ctx, "abs", (int)(this_instr - trace), this_instr, stack_pointer); _PyUOpInstruction *out_ptr = ctx->out_buffer.next; switch (opcode) { #include "optimizer_cases.c.h" default: DPRINTF(1, "\nUnknown opcode in abstract interpreter\n"); Py_UNREACHABLE(); } // If no ADD_OP was called during this iteration, copy the original instruction if (ctx->out_buffer.next == out_ptr) { *(ctx->out_buffer.next++) = *this_instr; } assert(ctx->frame != NULL); DUMP_UOPS(ctx, "out", out_ptr, stack_pointer); if (!CURRENT_FRAME_IS_INIT_SHIM() && !ctx->done) { DPRINTF(3, " stack_level %d\n", STACK_LEVEL()); ctx->frame->stack_pointer = stack_pointer; assert(STACK_LEVEL() >= 0); } } if (ctx->out_of_space) { DPRINTF(3, "\n"); DPRINTF(1, "Out of space in abstract interpreter\n"); } if (ctx->contradiction) { // Attempted to push a "bottom" (contradiction) symbol onto the stack. // This means that the abstract interpreter has optimized to trace // to an unreachable estate. // We *could* generate an _EXIT_TRACE or _FATAL_ERROR here, but hitting // bottom usually indicates an optimizer bug, so we are probably better off // retrying later. DPRINTF(3, "\n"); DPRINTF(1, "Hit bottom in abstract interpreter\n"); _Py_uop_abstractcontext_fini(ctx); OPT_STAT_INC(optimizer_contradiction); return 0; } /* Either reached the end or cannot optimize further, but there * would be no benefit in retrying later */ _Py_uop_abstractcontext_fini(ctx); // Check that the trace ends with a proper terminator if (uop_buffer_length(&ctx->out_buffer) > 0) { assert(is_terminator_uop(uop_buffer_last(&ctx->out_buffer))); } return uop_buffer_length(&ctx->out_buffer); error: DPRINTF(3, "\n"); DPRINTF(1, "Encountered error in abstract interpreter\n"); if (opcode <= MAX_UOP_ID) { OPT_ERROR_IN_OPCODE(opcode); } _Py_uop_abstractcontext_fini(ctx); assert(PyErr_Occurred()); PyErr_Clear(); return 0; } const uint16_t op_without_push[MAX_UOP_ID + 1] = { [_COPY] = _NOP, [_LOAD_CONST_INLINE] = _NOP, [_LOAD_CONST_INLINE_BORROW] = _NOP, [_LOAD_FAST] = _NOP, [_LOAD_FAST_BORROW] = _NOP, [_LOAD_SMALL_INT] = _NOP, [_PUSH_NULL] = _NOP, }; const bool op_skip[MAX_UOP_ID + 1] = { [_NOP] = true, [_CHECK_VALIDITY] = true, [_CHECK_PERIODIC] = true, [_SET_IP] = true, }; const uint16_t op_without_pop[MAX_UOP_ID + 1] = { [_POP_TOP] = _NOP, [_POP_TOP_NOP] = _NOP, [_POP_TOP_INT] = _NOP, [_POP_TOP_FLOAT] = _NOP, [_POP_TOP_UNICODE] = _NOP, }; static int remove_unneeded_uops(_PyUOpInstruction *buffer, int buffer_size) { /* Remove _SET_IP and _CHECK_VALIDITY where possible. * _SET_IP is needed if the following instruction escapes or * could error. _CHECK_VALIDITY is needed if the previous * instruction could have escaped. */ int last_set_ip = -1; bool may_have_escaped = true; for (int pc = 0; pc < buffer_size; pc++) { int opcode = buffer[pc].opcode; switch (opcode) { case _START_EXECUTOR: may_have_escaped = false; break; case _SET_IP: buffer[pc].opcode = _NOP; last_set_ip = pc; break; case _CHECK_VALIDITY: if (may_have_escaped) { may_have_escaped = false; } else { buffer[pc].opcode = _NOP; } break; case _EXIT_TRACE: default: { // Cancel out pushes and pops, repeatedly. So: // _LOAD_FAST + _POP_TOP + _POP_TOP + _LOAD_CONST_INLINE_BORROW + _POP_TOP // ...becomes: // _NOP + _NOP + _POP_TOP + _NOP + _NOP while (op_without_pop[opcode]) { _PyUOpInstruction *last = &buffer[pc - 1]; while (op_skip[last->opcode]) { last--; } if (op_without_push[last->opcode] && op_without_pop[opcode]) { last->opcode = op_without_push[last->opcode]; opcode = buffer[pc].opcode = op_without_pop[opcode]; if (op_without_pop[last->opcode]) { opcode = last->opcode; pc = (int)(last - buffer); } } else { break; } } /* _PUSH_FRAME doesn't escape or error, but it * does need the IP for the return address */ bool needs_ip = (opcode == _PUSH_FRAME || opcode == _YIELD_VALUE || opcode == _DYNAMIC_EXIT || opcode == _EXIT_TRACE); if (_PyUop_Flags[opcode] & HAS_ESCAPES_FLAG) { needs_ip = true; may_have_escaped = true; } if (needs_ip && last_set_ip >= 0) { assert(buffer[last_set_ip].opcode == _NOP); buffer[last_set_ip].opcode = _SET_IP; last_set_ip = -1; } if (opcode == _EXIT_TRACE) { return pc + 1; } break; } case _JUMP_TO_TOP: case _DYNAMIC_EXIT: case _DEOPT: return pc + 1; } } Py_UNREACHABLE(); } // 0 - failure, no error raised, just fall back to Tier 1 // -1 - failure, and raise error // > 0 - length of optimized trace int _Py_uop_analyze_and_optimize( _PyThreadStateImpl *tstate, _PyUOpInstruction *buffer, int length, int curr_stacklen, _PyUOpInstruction *output, _PyBloomFilter *dependencies ) { OPT_STAT_INC(optimizer_attempts); length = optimize_uops( tstate, buffer, length, curr_stacklen, output, dependencies); if (length == 0) { return length; } assert(length > 0); length = remove_unneeded_uops(output, length); assert(length > 0); OPT_STAT_INC(optimizer_successes); return length; } #endif /* _Py_TIER2 */ |
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