1 /* 2 * Copyright (c) 1999, 2012, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "c1/c1_IR.hpp" 27 #include "c1/c1_Instruction.hpp" 28 #include "c1/c1_InstructionPrinter.hpp" 29 #include "c1/c1_ValueStack.hpp" 30 #include "ci/ciObjArrayKlass.hpp" 31 #include "ci/ciTypeArrayKlass.hpp" 32 33 34 // Implementation of Instruction 35 36 37 int Instruction::dominator_depth() { 38 int result = -1; 39 if (block()) { 40 result = block()->dominator_depth(); 41 } 42 assert(result != -1 || this->as_Local(), "Only locals have dominator depth -1"); 43 return result; 44 } 45 46 Instruction::Condition Instruction::mirror(Condition cond) { 47 switch (cond) { 48 case eql: return eql; 49 case neq: return neq; 50 case lss: return gtr; 51 case leq: return geq; 52 case gtr: return lss; 53 case geq: return leq; 54 case aeq: return beq; 55 case beq: return aeq; 56 } 57 ShouldNotReachHere(); 58 return eql; 59 } 60 61 62 Instruction::Condition Instruction::negate(Condition cond) { 63 switch (cond) { 64 case eql: return neq; 65 case neq: return eql; 66 case lss: return geq; 67 case leq: return gtr; 68 case gtr: return leq; 69 case geq: return lss; 70 case aeq: assert(false, "Above equal cannot be negated"); 71 case beq: assert(false, "Below equal cannot be negated"); 72 } 73 ShouldNotReachHere(); 74 return eql; 75 } 76 77 void Instruction::update_exception_state(ValueStack* state) { 78 if (state != NULL && (state->kind() == ValueStack::EmptyExceptionState || state->kind() == ValueStack::ExceptionState)) { 79 assert(state->kind() == ValueStack::EmptyExceptionState || Compilation::current()->env()->jvmti_can_access_local_variables(), "unexpected state kind"); 80 _exception_state = state; 81 } else { 82 _exception_state = NULL; 83 } 84 } 85 86 // Prev without need to have BlockBegin 87 Instruction* Instruction::prev() { 88 Instruction* p = NULL; 89 Instruction* q = block(); 90 while (q != this) { 91 assert(q != NULL, "this is not in the block's instruction list"); 92 p = q; q = q->next(); 93 } 94 return p; 95 } 96 97 98 void Instruction::state_values_do(ValueVisitor* f) { 99 if (state_before() != NULL) { 100 state_before()->values_do(f); 101 } 102 if (exception_state() != NULL){ 103 exception_state()->values_do(f); 104 } 105 } 106 107 ciType* Instruction::exact_type() const { 108 ciType* t = declared_type(); 109 if (t != NULL && t->is_klass()) { 110 return t->as_klass()->exact_klass(); 111 } 112 return NULL; 113 } 114 115 116 #ifndef PRODUCT 117 void Instruction::check_state(ValueStack* state) { 118 if (state != NULL) { 119 state->verify(); 120 } 121 } 122 123 124 void Instruction::print() { 125 InstructionPrinter ip; 126 print(ip); 127 } 128 129 130 void Instruction::print_line() { 131 InstructionPrinter ip; 132 ip.print_line(this); 133 } 134 135 136 void Instruction::print(InstructionPrinter& ip) { 137 ip.print_head(); 138 ip.print_line(this); 139 tty->cr(); 140 } 141 #endif // PRODUCT 142 143 144 // perform constant and interval tests on index value 145 bool AccessIndexed::compute_needs_range_check() { 146 if (length()) { 147 Constant* clength = length()->as_Constant(); 148 Constant* cindex = index()->as_Constant(); 149 if (clength && cindex) { 150 IntConstant* l = clength->type()->as_IntConstant(); 151 IntConstant* i = cindex->type()->as_IntConstant(); 152 if (l && i && i->value() < l->value() && i->value() >= 0) { 153 return false; 154 } 155 } 156 } 157 158 if (!this->check_flag(NeedsRangeCheckFlag)) { 159 return false; 160 } 161 162 return true; 163 } 164 165 166 ciType* Constant::exact_type() const { 167 if (type()->is_object() && type()->as_ObjectType()->is_loaded()) { 168 return type()->as_ObjectType()->exact_type(); 169 } 170 return NULL; 171 } 172 173 ciType* LoadIndexed::exact_type() const { 174 ciType* array_type = array()->exact_type(); 175 if (array_type != NULL) { 176 assert(array_type->is_array_klass(), "what else?"); 177 ciArrayKlass* ak = (ciArrayKlass*)array_type; 178 179 if (ak->element_type()->is_instance_klass()) { 180 ciInstanceKlass* ik = (ciInstanceKlass*)ak->element_type(); 181 if (ik->is_loaded() && ik->is_final()) { 182 return ik; 183 } 184 } 185 } 186 return Instruction::exact_type(); 187 } 188 189 190 ciType* LoadIndexed::declared_type() const { 191 ciType* array_type = array()->declared_type(); 192 if (array_type == NULL || !array_type->is_loaded()) { 193 return NULL; 194 } 195 assert(array_type->is_array_klass(), "what else?"); 196 ciArrayKlass* ak = (ciArrayKlass*)array_type; 197 return ak->element_type(); 198 } 199 200 201 ciType* LoadField::declared_type() const { 202 return field()->type(); 203 } 204 205 206 ciType* NewTypeArray::exact_type() const { 207 return ciTypeArrayKlass::make(elt_type()); 208 } 209 210 ciType* NewObjectArray::exact_type() const { 211 return ciObjArrayKlass::make(klass()); 212 } 213 214 ciType* NewArray::declared_type() const { 215 return exact_type(); 216 } 217 218 ciType* NewInstance::exact_type() const { 219 return klass(); 220 } 221 222 ciType* NewInstance::declared_type() const { 223 return exact_type(); 224 } 225 226 ciType* CheckCast::declared_type() const { 227 return klass(); 228 } 229 230 // Implementation of ArithmeticOp 231 232 bool ArithmeticOp::is_commutative() const { 233 switch (op()) { 234 case Bytecodes::_iadd: // fall through 235 case Bytecodes::_ladd: // fall through 236 case Bytecodes::_fadd: // fall through 237 case Bytecodes::_dadd: // fall through 238 case Bytecodes::_imul: // fall through 239 case Bytecodes::_lmul: // fall through 240 case Bytecodes::_fmul: // fall through 241 case Bytecodes::_dmul: return true; 242 } 243 return false; 244 } 245 246 247 bool ArithmeticOp::can_trap() const { 248 switch (op()) { 249 case Bytecodes::_idiv: // fall through 250 case Bytecodes::_ldiv: // fall through 251 case Bytecodes::_irem: // fall through 252 case Bytecodes::_lrem: return true; 253 } 254 return false; 255 } 256 257 258 // Implementation of LogicOp 259 260 bool LogicOp::is_commutative() const { 261 #ifdef ASSERT 262 switch (op()) { 263 case Bytecodes::_iand: // fall through 264 case Bytecodes::_land: // fall through 265 case Bytecodes::_ior : // fall through 266 case Bytecodes::_lor : // fall through 267 case Bytecodes::_ixor: // fall through 268 case Bytecodes::_lxor: break; 269 default : ShouldNotReachHere(); 270 } 271 #endif 272 // all LogicOps are commutative 273 return true; 274 } 275 276 277 // Implementation of IfOp 278 279 bool IfOp::is_commutative() const { 280 return cond() == eql || cond() == neq; 281 } 282 283 284 // Implementation of StateSplit 285 286 void StateSplit::substitute(BlockList& list, BlockBegin* old_block, BlockBegin* new_block) { 287 NOT_PRODUCT(bool assigned = false;) 288 for (int i = 0; i < list.length(); i++) { 289 BlockBegin** b = list.adr_at(i); 290 if (*b == old_block) { 291 *b = new_block; 292 NOT_PRODUCT(assigned = true;) 293 } 294 } 295 assert(assigned == true, "should have assigned at least once"); 296 } 297 298 299 IRScope* StateSplit::scope() const { 300 return _state->scope(); 301 } 302 303 304 void StateSplit::state_values_do(ValueVisitor* f) { 305 Instruction::state_values_do(f); 306 if (state() != NULL) state()->values_do(f); 307 } 308 309 310 void BlockBegin::state_values_do(ValueVisitor* f) { 311 StateSplit::state_values_do(f); 312 313 if (is_set(BlockBegin::exception_entry_flag)) { 314 for (int i = 0; i < number_of_exception_states(); i++) { 315 exception_state_at(i)->values_do(f); 316 } 317 } 318 } 319 320 321 // Implementation of Invoke 322 323 324 Invoke::Invoke(Bytecodes::Code code, ValueType* result_type, Value recv, Values* args, 325 int vtable_index, ciMethod* target, ValueStack* state_before) 326 : StateSplit(result_type, state_before) 327 , _code(code) 328 , _recv(recv) 329 , _args(args) 330 , _vtable_index(vtable_index) 331 , _target(target) 332 { 333 set_flag(TargetIsLoadedFlag, target->is_loaded()); 334 set_flag(TargetIsFinalFlag, target_is_loaded() && target->is_final_method()); 335 set_flag(TargetIsStrictfpFlag, target_is_loaded() && target->is_strict()); 336 337 assert(args != NULL, "args must exist"); 338 #ifdef ASSERT 339 AssertValues assert_value; 340 values_do(&assert_value); 341 #endif 342 343 // provide an initial guess of signature size. 344 _signature = new BasicTypeList(number_of_arguments() + (has_receiver() ? 1 : 0)); 345 if (has_receiver()) { 346 _signature->append(as_BasicType(receiver()->type())); 347 } 348 for (int i = 0; i < number_of_arguments(); i++) { 349 ValueType* t = argument_at(i)->type(); 350 BasicType bt = as_BasicType(t); 351 _signature->append(bt); 352 } 353 } 354 355 356 void Invoke::state_values_do(ValueVisitor* f) { 357 StateSplit::state_values_do(f); 358 if (state_before() != NULL) state_before()->values_do(f); 359 if (state() != NULL) state()->values_do(f); 360 } 361 362 ciType* Invoke::declared_type() const { 363 ciType *t = _target->signature()->return_type(); 364 assert(t->basic_type() != T_VOID, "need return value of void method?"); 365 return t; 366 } 367 368 // Implementation of Contant 369 intx Constant::hash() const { 370 if (state_before() == NULL) { 371 switch (type()->tag()) { 372 case intTag: 373 return HASH2(name(), type()->as_IntConstant()->value()); 374 case addressTag: 375 return HASH2(name(), type()->as_AddressConstant()->value()); 376 case longTag: 377 { 378 jlong temp = type()->as_LongConstant()->value(); 379 return HASH3(name(), high(temp), low(temp)); 380 } 381 case floatTag: 382 return HASH2(name(), jint_cast(type()->as_FloatConstant()->value())); 383 case doubleTag: 384 { 385 jlong temp = jlong_cast(type()->as_DoubleConstant()->value()); 386 return HASH3(name(), high(temp), low(temp)); 387 } 388 case objectTag: 389 assert(type()->as_ObjectType()->is_loaded(), "can't handle unloaded values"); 390 return HASH2(name(), type()->as_ObjectType()->constant_value()); 391 case metaDataTag: 392 assert(type()->as_MetadataType()->is_loaded(), "can't handle unloaded values"); 393 return HASH2(name(), type()->as_MetadataType()->constant_value()); 394 default: 395 ShouldNotReachHere(); 396 } 397 } 398 return 0; 399 } 400 401 bool Constant::is_equal(Value v) const { 402 if (v->as_Constant() == NULL) return false; 403 404 switch (type()->tag()) { 405 case intTag: 406 { 407 IntConstant* t1 = type()->as_IntConstant(); 408 IntConstant* t2 = v->type()->as_IntConstant(); 409 return (t1 != NULL && t2 != NULL && 410 t1->value() == t2->value()); 411 } 412 case longTag: 413 { 414 LongConstant* t1 = type()->as_LongConstant(); 415 LongConstant* t2 = v->type()->as_LongConstant(); 416 return (t1 != NULL && t2 != NULL && 417 t1->value() == t2->value()); 418 } 419 case floatTag: 420 { 421 FloatConstant* t1 = type()->as_FloatConstant(); 422 FloatConstant* t2 = v->type()->as_FloatConstant(); 423 return (t1 != NULL && t2 != NULL && 424 jint_cast(t1->value()) == jint_cast(t2->value())); 425 } 426 case doubleTag: 427 { 428 DoubleConstant* t1 = type()->as_DoubleConstant(); 429 DoubleConstant* t2 = v->type()->as_DoubleConstant(); 430 return (t1 != NULL && t2 != NULL && 431 jlong_cast(t1->value()) == jlong_cast(t2->value())); 432 } 433 case objectTag: 434 { 435 ObjectType* t1 = type()->as_ObjectType(); 436 ObjectType* t2 = v->type()->as_ObjectType(); 437 return (t1 != NULL && t2 != NULL && 438 t1->is_loaded() && t2->is_loaded() && 439 t1->constant_value() == t2->constant_value()); 440 } 441 case metaDataTag: 442 { 443 MetadataType* t1 = type()->as_MetadataType(); 444 MetadataType* t2 = v->type()->as_MetadataType(); 445 return (t1 != NULL && t2 != NULL && 446 t1->is_loaded() && t2->is_loaded() && 447 t1->constant_value() == t2->constant_value()); 448 } 449 } 450 return false; 451 } 452 453 Constant::CompareResult Constant::compare(Instruction::Condition cond, Value right) const { 454 Constant* rc = right->as_Constant(); 455 // other is not a constant 456 if (rc == NULL) return not_comparable; 457 458 ValueType* lt = type(); 459 ValueType* rt = rc->type(); 460 // different types 461 if (lt->base() != rt->base()) return not_comparable; 462 switch (lt->tag()) { 463 case intTag: { 464 int x = lt->as_IntConstant()->value(); 465 int y = rt->as_IntConstant()->value(); 466 switch (cond) { 467 case If::eql: return x == y ? cond_true : cond_false; 468 case If::neq: return x != y ? cond_true : cond_false; 469 case If::lss: return x < y ? cond_true : cond_false; 470 case If::leq: return x <= y ? cond_true : cond_false; 471 case If::gtr: return x > y ? cond_true : cond_false; 472 case If::geq: return x >= y ? cond_true : cond_false; 473 } 474 break; 475 } 476 case longTag: { 477 jlong x = lt->as_LongConstant()->value(); 478 jlong y = rt->as_LongConstant()->value(); 479 switch (cond) { 480 case If::eql: return x == y ? cond_true : cond_false; 481 case If::neq: return x != y ? cond_true : cond_false; 482 case If::lss: return x < y ? cond_true : cond_false; 483 case If::leq: return x <= y ? cond_true : cond_false; 484 case If::gtr: return x > y ? cond_true : cond_false; 485 case If::geq: return x >= y ? cond_true : cond_false; 486 } 487 break; 488 } 489 case objectTag: { 490 ciObject* xvalue = lt->as_ObjectType()->constant_value(); 491 ciObject* yvalue = rt->as_ObjectType()->constant_value(); 492 assert(xvalue != NULL && yvalue != NULL, "not constants"); 493 if (xvalue->is_loaded() && yvalue->is_loaded()) { 494 switch (cond) { 495 case If::eql: return xvalue == yvalue ? cond_true : cond_false; 496 case If::neq: return xvalue != yvalue ? cond_true : cond_false; 497 } 498 } 499 break; 500 } 501 case metaDataTag: { 502 ciMetadata* xvalue = lt->as_MetadataType()->constant_value(); 503 ciMetadata* yvalue = rt->as_MetadataType()->constant_value(); 504 assert(xvalue != NULL && yvalue != NULL, "not constants"); 505 if (xvalue->is_loaded() && yvalue->is_loaded()) { 506 switch (cond) { 507 case If::eql: return xvalue == yvalue ? cond_true : cond_false; 508 case If::neq: return xvalue != yvalue ? cond_true : cond_false; 509 } 510 } 511 break; 512 } 513 } 514 return not_comparable; 515 } 516 517 518 // Implementation of BlockBegin 519 520 void BlockBegin::set_end(BlockEnd* end) { 521 assert(end != NULL, "should not reset block end to NULL"); 522 if (end == _end) { 523 return; 524 } 525 clear_end(); 526 527 // Set the new end 528 _end = end; 529 530 _successors.clear(); 531 // Now reset successors list based on BlockEnd 532 for (int i = 0; i < end->number_of_sux(); i++) { 533 BlockBegin* sux = end->sux_at(i); 534 _successors.append(sux); 535 sux->_predecessors.append(this); 536 } 537 _end->set_begin(this); 538 } 539 540 541 void BlockBegin::clear_end() { 542 // Must make the predecessors/successors match up with the 543 // BlockEnd's notion. 544 if (_end != NULL) { 545 // disconnect from the old end 546 _end->set_begin(NULL); 547 548 // disconnect this block from it's current successors 549 for (int i = 0; i < _successors.length(); i++) { 550 _successors.at(i)->remove_predecessor(this); 551 } 552 _end = NULL; 553 } 554 } 555 556 557 void BlockBegin::disconnect_edge(BlockBegin* from, BlockBegin* to) { 558 // disconnect any edges between from and to 559 #ifndef PRODUCT 560 if (PrintIR && Verbose) { 561 tty->print_cr("Disconnected edge B%d -> B%d", from->block_id(), to->block_id()); 562 } 563 #endif 564 for (int s = 0; s < from->number_of_sux();) { 565 BlockBegin* sux = from->sux_at(s); 566 if (sux == to) { 567 int index = sux->_predecessors.index_of(from); 568 if (index >= 0) { 569 sux->_predecessors.remove_at(index); 570 } 571 from->_successors.remove_at(s); 572 } else { 573 s++; 574 } 575 } 576 } 577 578 579 void BlockBegin::disconnect_from_graph() { 580 // disconnect this block from all other blocks 581 for (int p = 0; p < number_of_preds(); p++) { 582 pred_at(p)->remove_successor(this); 583 } 584 for (int s = 0; s < number_of_sux(); s++) { 585 sux_at(s)->remove_predecessor(this); 586 } 587 } 588 589 void BlockBegin::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) { 590 // modify predecessors before substituting successors 591 for (int i = 0; i < number_of_sux(); i++) { 592 if (sux_at(i) == old_sux) { 593 // remove old predecessor before adding new predecessor 594 // otherwise there is a dead predecessor in the list 595 new_sux->remove_predecessor(old_sux); 596 new_sux->add_predecessor(this); 597 } 598 } 599 old_sux->remove_predecessor(this); 600 end()->substitute_sux(old_sux, new_sux); 601 } 602 603 604 605 // In general it is not possible to calculate a value for the field "depth_first_number" 606 // of the inserted block, without recomputing the values of the other blocks 607 // in the CFG. Therefore the value of "depth_first_number" in BlockBegin becomes meaningless. 608 BlockBegin* BlockBegin::insert_block_between(BlockBegin* sux) { 609 int bci = sux->bci(); 610 // critical edge splitting may introduce a goto after a if and array 611 // bound check elimination may insert a predicate between the if and 612 // goto. The bci of the goto can't be the one of the if otherwise 613 // the state and bci are inconsistent and a deoptimization triggered 614 // by the predicate would lead to incorrect execution/a crash. 615 BlockBegin* new_sux = new BlockBegin(bci); 616 617 // mark this block (special treatment when block order is computed) 618 new_sux->set(critical_edge_split_flag); 619 620 // This goto is not a safepoint. 621 Goto* e = new Goto(sux, false); 622 new_sux->set_next(e, bci); 623 new_sux->set_end(e); 624 // setup states 625 ValueStack* s = end()->state(); 626 new_sux->set_state(s->copy(s->kind(), bci)); 627 e->set_state(s->copy(s->kind(), bci)); 628 assert(new_sux->state()->locals_size() == s->locals_size(), "local size mismatch!"); 629 assert(new_sux->state()->stack_size() == s->stack_size(), "stack size mismatch!"); 630 assert(new_sux->state()->locks_size() == s->locks_size(), "locks size mismatch!"); 631 632 // link predecessor to new block 633 end()->substitute_sux(sux, new_sux); 634 635 // The ordering needs to be the same, so remove the link that the 636 // set_end call above added and substitute the new_sux for this 637 // block. 638 sux->remove_predecessor(new_sux); 639 640 // the successor could be the target of a switch so it might have 641 // multiple copies of this predecessor, so substitute the new_sux 642 // for the first and delete the rest. 643 bool assigned = false; 644 BlockList& list = sux->_predecessors; 645 for (int i = 0; i < list.length(); i++) { 646 BlockBegin** b = list.adr_at(i); 647 if (*b == this) { 648 if (assigned) { 649 list.remove_at(i); 650 // reprocess this index 651 i--; 652 } else { 653 assigned = true; 654 *b = new_sux; 655 } 656 // link the new block back to it's predecessors. 657 new_sux->add_predecessor(this); 658 } 659 } 660 assert(assigned == true, "should have assigned at least once"); 661 return new_sux; 662 } 663 664 665 void BlockBegin::remove_successor(BlockBegin* pred) { 666 int idx; 667 while ((idx = _successors.index_of(pred)) >= 0) { 668 _successors.remove_at(idx); 669 } 670 } 671 672 673 void BlockBegin::add_predecessor(BlockBegin* pred) { 674 _predecessors.append(pred); 675 } 676 677 678 void BlockBegin::remove_predecessor(BlockBegin* pred) { 679 int idx; 680 while ((idx = _predecessors.index_of(pred)) >= 0) { 681 _predecessors.remove_at(idx); 682 } 683 } 684 685 686 void BlockBegin::add_exception_handler(BlockBegin* b) { 687 assert(b != NULL && (b->is_set(exception_entry_flag)), "exception handler must exist"); 688 // add only if not in the list already 689 if (!_exception_handlers.contains(b)) _exception_handlers.append(b); 690 } 691 692 int BlockBegin::add_exception_state(ValueStack* state) { 693 assert(is_set(exception_entry_flag), "only for xhandlers"); 694 if (_exception_states == NULL) { 695 _exception_states = new ValueStackStack(4); 696 } 697 _exception_states->append(state); 698 return _exception_states->length() - 1; 699 } 700 701 702 void BlockBegin::iterate_preorder(boolArray& mark, BlockClosure* closure) { 703 if (!mark.at(block_id())) { 704 mark.at_put(block_id(), true); 705 closure->block_do(this); 706 BlockEnd* e = end(); // must do this after block_do because block_do may change it! 707 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_preorder(mark, closure); } 708 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_preorder(mark, closure); } 709 } 710 } 711 712 713 void BlockBegin::iterate_postorder(boolArray& mark, BlockClosure* closure) { 714 if (!mark.at(block_id())) { 715 mark.at_put(block_id(), true); 716 BlockEnd* e = end(); 717 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_postorder(mark, closure); } 718 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_postorder(mark, closure); } 719 closure->block_do(this); 720 } 721 } 722 723 724 void BlockBegin::iterate_preorder(BlockClosure* closure) { 725 boolArray mark(number_of_blocks(), false); 726 iterate_preorder(mark, closure); 727 } 728 729 730 void BlockBegin::iterate_postorder(BlockClosure* closure) { 731 boolArray mark(number_of_blocks(), false); 732 iterate_postorder(mark, closure); 733 } 734 735 736 void BlockBegin::block_values_do(ValueVisitor* f) { 737 for (Instruction* n = this; n != NULL; n = n->next()) n->values_do(f); 738 } 739 740 741 #ifndef PRODUCT 742 #define TRACE_PHI(code) if (PrintPhiFunctions) { code; } 743 #else 744 #define TRACE_PHI(coce) 745 #endif 746 747 748 bool BlockBegin::try_merge(ValueStack* new_state) { 749 TRACE_PHI(tty->print_cr("********** try_merge for block B%d", block_id())); 750 751 // local variables used for state iteration 752 int index; 753 Value new_value, existing_value; 754 755 ValueStack* existing_state = state(); 756 if (existing_state == NULL) { 757 TRACE_PHI(tty->print_cr("first call of try_merge for this block")); 758 759 if (is_set(BlockBegin::was_visited_flag)) { 760 // this actually happens for complicated jsr/ret structures 761 return false; // BAILOUT in caller 762 } 763 764 // copy state because it is altered 765 new_state = new_state->copy(ValueStack::BlockBeginState, bci()); 766 767 // Use method liveness to invalidate dead locals 768 MethodLivenessResult liveness = new_state->scope()->method()->liveness_at_bci(bci()); 769 if (liveness.is_valid()) { 770 assert((int)liveness.size() == new_state->locals_size(), "error in use of liveness"); 771 772 for_each_local_value(new_state, index, new_value) { 773 if (!liveness.at(index) || new_value->type()->is_illegal()) { 774 new_state->invalidate_local(index); 775 TRACE_PHI(tty->print_cr("invalidating dead local %d", index)); 776 } 777 } 778 } 779 780 if (is_set(BlockBegin::parser_loop_header_flag)) { 781 TRACE_PHI(tty->print_cr("loop header block, initializing phi functions")); 782 783 for_each_stack_value(new_state, index, new_value) { 784 new_state->setup_phi_for_stack(this, index); 785 TRACE_PHI(tty->print_cr("creating phi-function %c%d for stack %d", new_state->stack_at(index)->type()->tchar(), new_state->stack_at(index)->id(), index)); 786 } 787 788 BitMap requires_phi_function = new_state->scope()->requires_phi_function(); 789 790 for_each_local_value(new_state, index, new_value) { 791 bool requires_phi = requires_phi_function.at(index) || (new_value->type()->is_double_word() && requires_phi_function.at(index + 1)); 792 if (requires_phi || !SelectivePhiFunctions) { 793 new_state->setup_phi_for_local(this, index); 794 TRACE_PHI(tty->print_cr("creating phi-function %c%d for local %d", new_state->local_at(index)->type()->tchar(), new_state->local_at(index)->id(), index)); 795 } 796 } 797 } 798 799 // initialize state of block 800 set_state(new_state); 801 802 } else if (existing_state->is_same(new_state)) { 803 TRACE_PHI(tty->print_cr("exisiting state found")); 804 805 assert(existing_state->scope() == new_state->scope(), "not matching"); 806 assert(existing_state->locals_size() == new_state->locals_size(), "not matching"); 807 assert(existing_state->stack_size() == new_state->stack_size(), "not matching"); 808 809 if (is_set(BlockBegin::was_visited_flag)) { 810 TRACE_PHI(tty->print_cr("loop header block, phis must be present")); 811 812 if (!is_set(BlockBegin::parser_loop_header_flag)) { 813 // this actually happens for complicated jsr/ret structures 814 return false; // BAILOUT in caller 815 } 816 817 for_each_local_value(existing_state, index, existing_value) { 818 Value new_value = new_state->local_at(index); 819 if (new_value == NULL || new_value->type()->tag() != existing_value->type()->tag()) { 820 // The old code invalidated the phi function here 821 // Because dead locals are replaced with NULL, this is a very rare case now, so simply bail out 822 return false; // BAILOUT in caller 823 } 824 } 825 826 #ifdef ASSERT 827 // check that all necessary phi functions are present 828 for_each_stack_value(existing_state, index, existing_value) { 829 assert(existing_value->as_Phi() != NULL && existing_value->as_Phi()->block() == this, "phi function required"); 830 } 831 for_each_local_value(existing_state, index, existing_value) { 832 assert(existing_value == new_state->local_at(index) || (existing_value->as_Phi() != NULL && existing_value->as_Phi()->as_Phi()->block() == this), "phi function required"); 833 } 834 #endif 835 836 } else { 837 TRACE_PHI(tty->print_cr("creating phi functions on demand")); 838 839 // create necessary phi functions for stack 840 for_each_stack_value(existing_state, index, existing_value) { 841 Value new_value = new_state->stack_at(index); 842 Phi* existing_phi = existing_value->as_Phi(); 843 844 if (new_value != existing_value && (existing_phi == NULL || existing_phi->block() != this)) { 845 existing_state->setup_phi_for_stack(this, index); 846 TRACE_PHI(tty->print_cr("creating phi-function %c%d for stack %d", existing_state->stack_at(index)->type()->tchar(), existing_state->stack_at(index)->id(), index)); 847 } 848 } 849 850 // create necessary phi functions for locals 851 for_each_local_value(existing_state, index, existing_value) { 852 Value new_value = new_state->local_at(index); 853 Phi* existing_phi = existing_value->as_Phi(); 854 855 if (new_value == NULL || new_value->type()->tag() != existing_value->type()->tag()) { 856 existing_state->invalidate_local(index); 857 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index)); 858 } else if (new_value != existing_value && (existing_phi == NULL || existing_phi->block() != this)) { 859 existing_state->setup_phi_for_local(this, index); 860 TRACE_PHI(tty->print_cr("creating phi-function %c%d for local %d", existing_state->local_at(index)->type()->tchar(), existing_state->local_at(index)->id(), index)); 861 } 862 } 863 } 864 865 assert(existing_state->caller_state() == new_state->caller_state(), "caller states must be equal"); 866 867 } else { 868 assert(false, "stack or locks not matching (invalid bytecodes)"); 869 return false; 870 } 871 872 TRACE_PHI(tty->print_cr("********** try_merge for block B%d successful", block_id())); 873 874 return true; 875 } 876 877 878 #ifndef PRODUCT 879 void BlockBegin::print_block() { 880 InstructionPrinter ip; 881 print_block(ip, false); 882 } 883 884 885 void BlockBegin::print_block(InstructionPrinter& ip, bool live_only) { 886 ip.print_instr(this); tty->cr(); 887 ip.print_stack(this->state()); tty->cr(); 888 ip.print_inline_level(this); 889 ip.print_head(); 890 for (Instruction* n = next(); n != NULL; n = n->next()) { 891 if (!live_only || n->is_pinned() || n->use_count() > 0) { 892 ip.print_line(n); 893 } 894 } 895 tty->cr(); 896 } 897 #endif // PRODUCT 898 899 900 // Implementation of BlockList 901 902 void BlockList::iterate_forward (BlockClosure* closure) { 903 const int l = length(); 904 for (int i = 0; i < l; i++) closure->block_do(at(i)); 905 } 906 907 908 void BlockList::iterate_backward(BlockClosure* closure) { 909 for (int i = length() - 1; i >= 0; i--) closure->block_do(at(i)); 910 } 911 912 913 void BlockList::blocks_do(void f(BlockBegin*)) { 914 for (int i = length() - 1; i >= 0; i--) f(at(i)); 915 } 916 917 918 void BlockList::values_do(ValueVisitor* f) { 919 for (int i = length() - 1; i >= 0; i--) at(i)->block_values_do(f); 920 } 921 922 923 #ifndef PRODUCT 924 void BlockList::print(bool cfg_only, bool live_only) { 925 InstructionPrinter ip; 926 for (int i = 0; i < length(); i++) { 927 BlockBegin* block = at(i); 928 if (cfg_only) { 929 ip.print_instr(block); tty->cr(); 930 } else { 931 block->print_block(ip, live_only); 932 } 933 } 934 } 935 #endif // PRODUCT 936 937 938 // Implementation of BlockEnd 939 940 void BlockEnd::set_begin(BlockBegin* begin) { 941 BlockList* sux = NULL; 942 if (begin != NULL) { 943 sux = begin->successors(); 944 } else if (this->begin() != NULL) { 945 // copy our sux list 946 BlockList* sux = new BlockList(this->begin()->number_of_sux()); 947 for (int i = 0; i < this->begin()->number_of_sux(); i++) { 948 sux->append(this->begin()->sux_at(i)); 949 } 950 } 951 _sux = sux; 952 } 953 954 955 void BlockEnd::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) { 956 substitute(*_sux, old_sux, new_sux); 957 } 958 959 960 // Implementation of Phi 961 962 // Normal phi functions take their operands from the last instruction of the 963 // predecessor. Special handling is needed for xhanlder entries because there 964 // the state of arbitrary instructions are needed. 965 966 Value Phi::operand_at(int i) const { 967 ValueStack* state; 968 if (_block->is_set(BlockBegin::exception_entry_flag)) { 969 state = _block->exception_state_at(i); 970 } else { 971 state = _block->pred_at(i)->end()->state(); 972 } 973 assert(state != NULL, ""); 974 975 if (is_local()) { 976 return state->local_at(local_index()); 977 } else { 978 return state->stack_at(stack_index()); 979 } 980 } 981 982 983 int Phi::operand_count() const { 984 if (_block->is_set(BlockBegin::exception_entry_flag)) { 985 return _block->number_of_exception_states(); 986 } else { 987 return _block->number_of_preds(); 988 } 989 } 990 991 #ifdef ASSERT 992 // Constructor of Assert 993 Assert::Assert(Value x, Condition cond, bool unordered_is_true, Value y) : Instruction(illegalType) 994 , _x(x) 995 , _cond(cond) 996 , _y(y) 997 { 998 set_flag(UnorderedIsTrueFlag, unordered_is_true); 999 assert(x->type()->tag() == y->type()->tag(), "types must match"); 1000 pin(); 1001 1002 stringStream strStream; 1003 Compilation::current()->method()->print_name(&strStream); 1004 1005 stringStream strStream1; 1006 InstructionPrinter ip1(1, &strStream1); 1007 ip1.print_instr(x); 1008 1009 stringStream strStream2; 1010 InstructionPrinter ip2(1, &strStream2); 1011 ip2.print_instr(y); 1012 1013 stringStream ss; 1014 ss.print("Assertion %s %s %s in method %s", strStream1.as_string(), ip2.cond_name(cond), strStream2.as_string(), strStream.as_string()); 1015 1016 _message = ss.as_string(); 1017 } 1018 #endif 1019 1020 void RangeCheckPredicate::check_state() { 1021 assert(state()->kind() != ValueStack::EmptyExceptionState && state()->kind() != ValueStack::ExceptionState, "will deopt with empty state"); 1022 } 1023 1024 void ProfileInvoke::state_values_do(ValueVisitor* f) { 1025 if (state() != NULL) state()->values_do(f); 1026 }