1 /*
2 * Copyright (c) 1999, 2025, 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 "c1/c1_Instruction.hpp"
26 #include "c1/c1_InstructionPrinter.hpp"
27 #include "c1/c1_IR.hpp"
28 #include "c1/c1_ValueStack.hpp"
29 #include "ci/ciObjArrayKlass.hpp"
30 #include "ci/ciTypeArrayKlass.hpp"
31 #include "utilities/bitMap.inline.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 != nullptr && (state->kind() == ValueStack::EmptyExceptionState || state->kind() == ValueStack::ExceptionState)) {
79 assert(state->kind() == ValueStack::EmptyExceptionState || Compilation::current()->env()->should_retain_local_variables(), "unexpected state kind");
80 _exception_state = state;
81 } else {
82 _exception_state = nullptr;
83 }
84 }
85
86 // Prev without need to have BlockBegin
87 Instruction* Instruction::prev() {
88 Instruction* p = nullptr;
89 Instruction* q = block();
90 while (q != this) {
91 assert(q != nullptr, "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() != nullptr) {
100 state_before()->values_do(f);
101 }
102 if (exception_state() != nullptr) {
103 exception_state()->values_do(f);
104 }
105 }
106
107 ciType* Instruction::exact_type() const {
108 ciType* t = declared_type();
109 if (t != nullptr && t->is_klass()) {
110 return t->as_klass()->exact_klass();
111 }
112 return nullptr;
113 }
114
115
116 #ifndef PRODUCT
117 void Instruction::check_state(ValueStack* state) {
118 if (state != nullptr) {
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 nullptr;
171 }
172
173 ciType* LoadIndexed::exact_type() const {
174 ciType* array_type = array()->exact_type();
175 if (array_type != nullptr) {
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 == nullptr || !array_type->is_loaded()) {
193 return nullptr;
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 default : return false;
243 }
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 default : return false;
254 }
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(); break;
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() != nullptr) 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 ciMethod* target, ValueStack* state_before)
326 : StateSplit(result_type, state_before)
327 , _code(code)
328 , _recv(recv)
329 , _args(args)
330 , _target(target)
331 {
332 set_flag(TargetIsLoadedFlag, target->is_loaded());
333 set_flag(TargetIsFinalFlag, target_is_loaded() && target->is_final_method());
334
335 assert(args != nullptr, "args must exist");
336 #ifdef ASSERT
337 AssertValues assert_value;
338 values_do(&assert_value);
339 #endif
340
341 // provide an initial guess of signature size.
342 _signature = new BasicTypeList(number_of_arguments() + (has_receiver() ? 1 : 0));
343 if (has_receiver()) {
344 _signature->append(as_BasicType(receiver()->type()));
345 }
346 for (int i = 0; i < number_of_arguments(); i++) {
347 ValueType* t = argument_at(i)->type();
348 BasicType bt = as_BasicType(t);
349 _signature->append(bt);
350 }
351 }
352
353
354 void Invoke::state_values_do(ValueVisitor* f) {
355 StateSplit::state_values_do(f);
356 if (state_before() != nullptr) state_before()->values_do(f);
357 if (state() != nullptr) state()->values_do(f);
358 }
359
360 ciType* Invoke::declared_type() const {
361 ciSignature* declared_signature = state()->scope()->method()->get_declared_signature_at_bci(state()->bci());
362 ciType *t = declared_signature->return_type();
363 assert(t->basic_type() != T_VOID, "need return value of void method?");
364 return t;
365 }
366
367 // Implementation of Constant
368 intx Constant::hash() const {
369 if (state_before() == nullptr) {
370 switch (type()->tag()) {
371 case intTag:
372 return HASH2(name(), type()->as_IntConstant()->value());
373 case addressTag:
374 return HASH2(name(), type()->as_AddressConstant()->value());
375 case longTag:
376 {
377 jlong temp = type()->as_LongConstant()->value();
378 return HASH3(name(), high(temp), low(temp));
379 }
380 case floatTag:
381 return HASH2(name(), jint_cast(type()->as_FloatConstant()->value()));
382 case doubleTag:
383 {
384 jlong temp = jlong_cast(type()->as_DoubleConstant()->value());
385 return HASH3(name(), high(temp), low(temp));
386 }
387 case objectTag:
388 assert(type()->as_ObjectType()->is_loaded(), "can't handle unloaded values");
389 return HASH2(name(), type()->as_ObjectType()->constant_value());
390 case metaDataTag:
391 assert(type()->as_MetadataType()->is_loaded(), "can't handle unloaded values");
392 return HASH2(name(), type()->as_MetadataType()->constant_value());
393 default:
394 ShouldNotReachHere();
395 }
396 }
397 return 0;
398 }
399
400 bool Constant::is_equal(Value v) const {
401 if (v->as_Constant() == nullptr) return false;
402
403 switch (type()->tag()) {
404 case intTag:
405 {
406 IntConstant* t1 = type()->as_IntConstant();
407 IntConstant* t2 = v->type()->as_IntConstant();
408 return (t1 != nullptr && t2 != nullptr &&
409 t1->value() == t2->value());
410 }
411 case longTag:
412 {
413 LongConstant* t1 = type()->as_LongConstant();
414 LongConstant* t2 = v->type()->as_LongConstant();
415 return (t1 != nullptr && t2 != nullptr &&
416 t1->value() == t2->value());
417 }
418 case floatTag:
419 {
420 FloatConstant* t1 = type()->as_FloatConstant();
421 FloatConstant* t2 = v->type()->as_FloatConstant();
422 return (t1 != nullptr && t2 != nullptr &&
423 jint_cast(t1->value()) == jint_cast(t2->value()));
424 }
425 case doubleTag:
426 {
427 DoubleConstant* t1 = type()->as_DoubleConstant();
428 DoubleConstant* t2 = v->type()->as_DoubleConstant();
429 return (t1 != nullptr && t2 != nullptr &&
430 jlong_cast(t1->value()) == jlong_cast(t2->value()));
431 }
432 case objectTag:
433 {
434 ObjectType* t1 = type()->as_ObjectType();
435 ObjectType* t2 = v->type()->as_ObjectType();
436 return (t1 != nullptr && t2 != nullptr &&
437 t1->is_loaded() && t2->is_loaded() &&
438 t1->constant_value() == t2->constant_value());
439 }
440 case metaDataTag:
441 {
442 MetadataType* t1 = type()->as_MetadataType();
443 MetadataType* t2 = v->type()->as_MetadataType();
444 return (t1 != nullptr && t2 != nullptr &&
445 t1->is_loaded() && t2->is_loaded() &&
446 t1->constant_value() == t2->constant_value());
447 }
448 default:
449 return false;
450 }
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 == nullptr) 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 default : break;
474 }
475 break;
476 }
477 case longTag: {
478 jlong x = lt->as_LongConstant()->value();
479 jlong y = rt->as_LongConstant()->value();
480 switch (cond) {
481 case If::eql: return x == y ? cond_true : cond_false;
482 case If::neq: return x != y ? cond_true : cond_false;
483 case If::lss: return x < y ? cond_true : cond_false;
484 case If::leq: return x <= y ? cond_true : cond_false;
485 case If::gtr: return x > y ? cond_true : cond_false;
486 case If::geq: return x >= y ? cond_true : cond_false;
487 default : break;
488 }
489 break;
490 }
491 case objectTag: {
492 ciObject* xvalue = lt->as_ObjectType()->constant_value();
493 ciObject* yvalue = rt->as_ObjectType()->constant_value();
494 assert(xvalue != nullptr && yvalue != nullptr, "not constants");
495 if (xvalue->is_loaded() && yvalue->is_loaded()) {
496 switch (cond) {
497 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
498 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
499 default : break;
500 }
501 }
502 break;
503 }
504 case metaDataTag: {
505 ciMetadata* xvalue = lt->as_MetadataType()->constant_value();
506 ciMetadata* yvalue = rt->as_MetadataType()->constant_value();
507 assert(xvalue != nullptr && yvalue != nullptr, "not constants");
508 if (xvalue->is_loaded() && yvalue->is_loaded()) {
509 switch (cond) {
510 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
511 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
512 default : break;
513 }
514 }
515 break;
516 }
517 default:
518 break;
519 }
520 return not_comparable;
521 }
522
523
524 // Implementation of BlockBegin
525
526 void BlockBegin::set_end(BlockEnd* new_end) { // Assumes that no predecessor of new_end still has it as its successor
527 assert(new_end != nullptr, "Should not reset block new_end to null");
528 if (new_end == _end) return;
529
530 // Remove this block as predecessor of its current successors
531 if (_end != nullptr) {
532 for (int i = 0; i < number_of_sux(); i++) {
533 sux_at(i)->remove_predecessor(this);
534 }
535 }
536
537 _end = new_end;
538
539 // Add this block as predecessor of its new successors
540 for (int i = 0; i < number_of_sux(); i++) {
541 sux_at(i)->add_predecessor(this);
542 }
543 }
544
545
546 void BlockBegin::disconnect_edge(BlockBegin* from, BlockBegin* to) {
547 // disconnect any edges between from and to
548 #ifndef PRODUCT
549 if (PrintIR && Verbose) {
550 tty->print_cr("Disconnected edge B%d -> B%d", from->block_id(), to->block_id());
551 }
552 #endif
553 for (int s = 0; s < from->number_of_sux();) {
554 BlockBegin* sux = from->sux_at(s);
555 if (sux == to) {
556 int index = sux->_predecessors.find(from);
557 if (index >= 0) {
558 sux->_predecessors.remove_at(index);
559 }
560 from->end()->remove_sux_at(s);
561 } else {
562 s++;
563 }
564 }
565 }
566
567
568 void BlockBegin::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
569 // modify predecessors before substituting successors
570 for (int i = 0; i < number_of_sux(); i++) {
571 if (sux_at(i) == old_sux) {
572 // remove old predecessor before adding new predecessor
573 // otherwise there is a dead predecessor in the list
574 new_sux->remove_predecessor(old_sux);
575 new_sux->add_predecessor(this);
576 }
577 }
578 old_sux->remove_predecessor(this);
579 end()->substitute_sux(old_sux, new_sux);
580 }
581
582
583
584 // In general it is not possible to calculate a value for the field "depth_first_number"
585 // of the inserted block, without recomputing the values of the other blocks
586 // in the CFG. Therefore the value of "depth_first_number" in BlockBegin becomes meaningless.
587 BlockBegin* BlockBegin::insert_block_between(BlockBegin* sux) {
588 assert(!sux->is_set(critical_edge_split_flag), "sanity check");
589
590 int bci = sux->bci();
591 // critical edge splitting may introduce a goto after a if and array
592 // bound check elimination may insert a predicate between the if and
593 // goto. The bci of the goto can't be the one of the if otherwise
594 // the state and bci are inconsistent and a deoptimization triggered
595 // by the predicate would lead to incorrect execution/a crash.
596 BlockBegin* new_sux = new BlockBegin(bci);
597
598 // mark this block (special treatment when block order is computed)
599 new_sux->set(critical_edge_split_flag);
600
601 // This goto is not a safepoint.
602 Goto* e = new Goto(sux, false);
603 new_sux->set_next(e, bci);
604 new_sux->set_end(e);
605 // setup states
606 ValueStack* s = end()->state();
607 new_sux->set_state(s->copy(s->kind(), bci));
608 e->set_state(s->copy(s->kind(), bci));
609 assert(new_sux->state()->locals_size() == s->locals_size(), "local size mismatch!");
610 assert(new_sux->state()->stack_size() == s->stack_size(), "stack size mismatch!");
611 assert(new_sux->state()->locks_size() == s->locks_size(), "locks size mismatch!");
612
613 // link predecessor to new block
614 end()->substitute_sux(sux, new_sux);
615
616 // The ordering needs to be the same, so remove the link that the
617 // set_end call above added and substitute the new_sux for this
618 // block.
619 sux->remove_predecessor(new_sux);
620
621 // the successor could be the target of a switch so it might have
622 // multiple copies of this predecessor, so substitute the new_sux
623 // for the first and delete the rest.
624 bool assigned = false;
625 BlockList& list = sux->_predecessors;
626 for (int i = 0; i < list.length(); i++) {
627 BlockBegin** b = list.adr_at(i);
628 if (*b == this) {
629 if (assigned) {
630 list.remove_at(i);
631 // reprocess this index
632 i--;
633 } else {
634 assigned = true;
635 *b = new_sux;
636 }
637 // link the new block back to it's predecessors.
638 new_sux->add_predecessor(this);
639 }
640 }
641 assert(assigned == true, "should have assigned at least once");
642 return new_sux;
643 }
644
645
646 void BlockBegin::add_predecessor(BlockBegin* pred) {
647 _predecessors.append(pred);
648 }
649
650
651 void BlockBegin::remove_predecessor(BlockBegin* pred) {
652 int idx;
653 while ((idx = _predecessors.find(pred)) >= 0) {
654 _predecessors.remove_at(idx);
655 }
656 }
657
658
659 void BlockBegin::add_exception_handler(BlockBegin* b) {
660 assert(b != nullptr && (b->is_set(exception_entry_flag)), "exception handler must exist");
661 // add only if not in the list already
662 if (!_exception_handlers.contains(b)) _exception_handlers.append(b);
663 }
664
665 int BlockBegin::add_exception_state(ValueStack* state) {
666 assert(is_set(exception_entry_flag), "only for xhandlers");
667 if (_exception_states == nullptr) {
668 _exception_states = new ValueStackStack(4);
669 }
670 _exception_states->append(state);
671 return _exception_states->length() - 1;
672 }
673
674
675 void BlockBegin::iterate_preorder(boolArray& mark, BlockClosure* closure) {
676 if (!mark.at(block_id())) {
677 mark.at_put(block_id(), true);
678 closure->block_do(this);
679 BlockEnd* e = end(); // must do this after block_do because block_do may change it!
680 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_preorder(mark, closure); }
681 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_preorder(mark, closure); }
682 }
683 }
684
685
686 void BlockBegin::iterate_postorder(boolArray& mark, BlockClosure* closure) {
687 if (!mark.at(block_id())) {
688 mark.at_put(block_id(), true);
689 BlockEnd* e = end();
690 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_postorder(mark, closure); }
691 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_postorder(mark, closure); }
692 closure->block_do(this);
693 }
694 }
695
696
697 void BlockBegin::iterate_preorder(BlockClosure* closure) {
698 int mark_len = number_of_blocks();
699 boolArray mark(mark_len, mark_len, false);
700 iterate_preorder(mark, closure);
701 }
702
703
704 void BlockBegin::iterate_postorder(BlockClosure* closure) {
705 int mark_len = number_of_blocks();
706 boolArray mark(mark_len, mark_len, false);
707 iterate_postorder(mark, closure);
708 }
709
710
711 void BlockBegin::block_values_do(ValueVisitor* f) {
712 for (Instruction* n = this; n != nullptr; n = n->next()) n->values_do(f);
713 }
714
715
716 #ifndef PRODUCT
717 #define TRACE_PHI(code) if (PrintPhiFunctions) { code; }
718 #else
719 #define TRACE_PHI(coce)
720 #endif
721
722
723 bool BlockBegin::try_merge(ValueStack* new_state, bool has_irreducible_loops) {
724 TRACE_PHI(tty->print_cr("********** try_merge for block B%d", block_id()));
725
726 // local variables used for state iteration
727 int index;
728 Value new_value, existing_value;
729
730 ValueStack* existing_state = state();
731 if (existing_state == nullptr) {
732 TRACE_PHI(tty->print_cr("first call of try_merge for this block"));
733
734 if (is_set(BlockBegin::was_visited_flag)) {
735 // this actually happens for complicated jsr/ret structures
736 return false; // BAILOUT in caller
737 }
738
739 // copy state because it is altered
740 new_state = new_state->copy(ValueStack::BlockBeginState, bci());
741
742 // Use method liveness to invalidate dead locals
743 MethodLivenessResult liveness = new_state->scope()->method()->liveness_at_bci(bci());
744 if (liveness.is_valid()) {
745 assert((int)liveness.size() == new_state->locals_size(), "error in use of liveness");
746
747 for_each_local_value(new_state, index, new_value) {
748 if (!liveness.at(index) || new_value->type()->is_illegal()) {
749 new_state->invalidate_local(index);
750 TRACE_PHI(tty->print_cr("invalidating dead local %d", index));
751 }
752 }
753 }
754
755 if (is_set(BlockBegin::parser_loop_header_flag)) {
756 TRACE_PHI(tty->print_cr("loop header block, initializing phi functions"));
757
758 for_each_stack_value(new_state, index, new_value) {
759 new_state->setup_phi_for_stack(this, index);
760 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));
761 }
762
763 BitMap& requires_phi_function = new_state->scope()->requires_phi_function();
764 for_each_local_value(new_state, index, new_value) {
765 bool requires_phi = requires_phi_function.at(index) || (new_value->type()->is_double_word() && requires_phi_function.at(index + 1));
766 if (requires_phi || !SelectivePhiFunctions || has_irreducible_loops) {
767 new_state->setup_phi_for_local(this, index);
768 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));
769 }
770 }
771 }
772
773 // initialize state of block
774 set_state(new_state);
775
776 } else if (existing_state->is_same(new_state)) {
777 TRACE_PHI(tty->print_cr("existing state found"));
778
779 assert(existing_state->scope() == new_state->scope(), "not matching");
780 assert(existing_state->locals_size() == new_state->locals_size(), "not matching");
781 assert(existing_state->stack_size() == new_state->stack_size(), "not matching");
782
783 if (is_set(BlockBegin::was_visited_flag)) {
784 TRACE_PHI(tty->print_cr("loop header block, phis must be present"));
785
786 if (!is_set(BlockBegin::parser_loop_header_flag)) {
787 // this actually happens for complicated jsr/ret structures
788 return false; // BAILOUT in caller
789 }
790
791 for_each_local_value(existing_state, index, existing_value) {
792 Value new_value = new_state->local_at(index);
793 if (new_value == nullptr || new_value->type()->tag() != existing_value->type()->tag()) {
794 Phi* existing_phi = existing_value->as_Phi();
795 if (existing_phi == nullptr) {
796 return false; // BAILOUT in caller
797 }
798 // Invalidate the phi function here. This case is very rare except for
799 // JVMTI capability "can_access_local_variables".
800 // In really rare cases we will bail out in LIRGenerator::move_to_phi.
801 existing_phi->make_illegal();
802 existing_state->invalidate_local(index);
803 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
804 }
805
806 if (existing_value != new_state->local_at(index) && existing_value->as_Phi() == nullptr) {
807 TRACE_PHI(tty->print_cr("required phi for local %d is missing, irreducible loop?", index));
808 return false; // BAILOUT in caller
809 }
810 }
811
812 #ifdef ASSERT
813 // check that all necessary phi functions are present
814 for_each_stack_value(existing_state, index, existing_value) {
815 assert(existing_value->as_Phi() != nullptr && existing_value->as_Phi()->block() == this, "phi function required");
816 }
817 for_each_local_value(existing_state, index, existing_value) {
818 assert(existing_value == new_state->local_at(index) || (existing_value->as_Phi() != nullptr && existing_value->as_Phi()->as_Phi()->block() == this), "phi function required");
819 }
820 #endif
821
822 } else {
823 TRACE_PHI(tty->print_cr("creating phi functions on demand"));
824
825 // create necessary phi functions for stack
826 for_each_stack_value(existing_state, index, existing_value) {
827 Value new_value = new_state->stack_at(index);
828 Phi* existing_phi = existing_value->as_Phi();
829
830 if (new_value != existing_value && (existing_phi == nullptr || existing_phi->block() != this)) {
831 existing_state->setup_phi_for_stack(this, index);
832 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));
833 }
834 }
835
836 // create necessary phi functions for locals
837 for_each_local_value(existing_state, index, existing_value) {
838 Value new_value = new_state->local_at(index);
839 Phi* existing_phi = existing_value->as_Phi();
840
841 if (new_value == nullptr || new_value->type()->tag() != existing_value->type()->tag()) {
842 existing_state->invalidate_local(index);
843 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
844 } else if (new_value != existing_value && (existing_phi == nullptr || existing_phi->block() != this)) {
845 existing_state->setup_phi_for_local(this, index);
846 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));
847 }
848 }
849 }
850
851 assert(existing_state->caller_state() == new_state->caller_state(), "caller states must be equal");
852
853 } else {
854 assert(false, "stack or locks not matching (invalid bytecodes)");
855 return false;
856 }
857
858 TRACE_PHI(tty->print_cr("********** try_merge for block B%d successful", block_id()));
859
860 return true;
861 }
862
863
864 #ifndef PRODUCT
865 void BlockBegin::print_block() {
866 InstructionPrinter ip;
867 print_block(ip, false);
868 }
869
870
871 void BlockBegin::print_block(InstructionPrinter& ip, bool live_only) {
872 ip.print_instr(this); tty->cr();
873 ip.print_stack(this->state()); tty->cr();
874 ip.print_inline_level(this);
875 ip.print_head();
876 for (Instruction* n = next(); n != nullptr; n = n->next()) {
877 if (!live_only || n->is_pinned() || n->use_count() > 0) {
878 ip.print_line(n);
879 }
880 }
881 tty->cr();
882 }
883 #endif // PRODUCT
884
885
886 // Implementation of BlockList
887
888 void BlockList::iterate_forward (BlockClosure* closure) {
889 const int l = length();
890 for (int i = 0; i < l; i++) closure->block_do(at(i));
891 }
892
893
894 void BlockList::iterate_backward(BlockClosure* closure) {
895 for (int i = length() - 1; i >= 0; i--) closure->block_do(at(i));
896 }
897
898
899 void BlockList::values_do(ValueVisitor* f) {
900 for (int i = length() - 1; i >= 0; i--) at(i)->block_values_do(f);
901 }
902
903
904 #ifndef PRODUCT
905 void BlockList::print(bool cfg_only, bool live_only) {
906 InstructionPrinter ip;
907 for (int i = 0; i < length(); i++) {
908 BlockBegin* block = at(i);
909 if (cfg_only) {
910 ip.print_instr(block); tty->cr();
911 } else {
912 block->print_block(ip, live_only);
913 }
914 }
915 }
916 #endif // PRODUCT
917
918
919 // Implementation of BlockEnd
920
921 void BlockEnd::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
922 substitute(*_sux, old_sux, new_sux);
923 }
924
925 // Implementation of Phi
926
927 // Normal phi functions take their operands from the last instruction of the
928 // predecessor. Special handling is needed for xhanlder entries because there
929 // the state of arbitrary instructions are needed.
930
931 Value Phi::operand_at(int i) const {
932 ValueStack* state;
933 if (_block->is_set(BlockBegin::exception_entry_flag)) {
934 state = _block->exception_state_at(i);
935 } else {
936 state = _block->pred_at(i)->end()->state();
937 }
938 assert(state != nullptr, "");
939
940 if (is_local()) {
941 return state->local_at(local_index());
942 } else {
943 return state->stack_at(stack_index());
944 }
945 }
946
947
948 int Phi::operand_count() const {
949 if (_block->is_set(BlockBegin::exception_entry_flag)) {
950 return _block->number_of_exception_states();
951 } else {
952 return _block->number_of_preds();
953 }
954 }
955
956 #ifdef ASSERT
957 // Constructor of Assert
958 Assert::Assert(Value x, Condition cond, bool unordered_is_true, Value y) : Instruction(illegalType)
959 , _x(x)
960 , _cond(cond)
961 , _y(y)
962 {
963 set_flag(UnorderedIsTrueFlag, unordered_is_true);
964 assert(x->type()->tag() == y->type()->tag(), "types must match");
965 pin();
966
967 stringStream strStream;
968 Compilation::current()->method()->print_name(&strStream);
969
970 stringStream strStream1;
971 InstructionPrinter ip1(1, &strStream1);
972 ip1.print_instr(x);
973
974 stringStream strStream2;
975 InstructionPrinter ip2(1, &strStream2);
976 ip2.print_instr(y);
977
978 stringStream ss;
979 ss.print("Assertion %s %s %s in method %s", strStream1.freeze(), ip2.cond_name(cond), strStream2.freeze(), strStream.freeze());
980
981 _message = ss.as_string();
982 }
983 #endif
984
985 void RangeCheckPredicate::check_state() {
986 assert(state()->kind() != ValueStack::EmptyExceptionState && state()->kind() != ValueStack::ExceptionState, "will deopt with empty state");
987 }
988
989 void ProfileInvoke::state_values_do(ValueVisitor* f) {
990 if (state() != nullptr) state()->values_do(f);
991 }