1 /*
2 * Copyright (c) 1999, 2024, 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 #include "utilities/bitMap.inline.hpp"
33
34
35 // Implementation of Instruction
36
37
38 int Instruction::dominator_depth() {
39 int result = -1;
40 if (block()) {
41 result = block()->dominator_depth();
42 }
43 assert(result != -1 || this->as_Local(), "Only locals have dominator depth -1");
44 return result;
45 }
46
47 Instruction::Condition Instruction::mirror(Condition cond) {
48 switch (cond) {
49 case eql: return eql;
50 case neq: return neq;
51 case lss: return gtr;
52 case leq: return geq;
53 case gtr: return lss;
54 case geq: return leq;
55 case aeq: return beq;
56 case beq: return aeq;
57 }
58 ShouldNotReachHere();
59 return eql;
60 }
61
62
63 Instruction::Condition Instruction::negate(Condition cond) {
64 switch (cond) {
65 case eql: return neq;
66 case neq: return eql;
67 case lss: return geq;
68 case leq: return gtr;
69 case gtr: return leq;
70 case geq: return lss;
71 case aeq: assert(false, "Above equal cannot be negated");
72 case beq: assert(false, "Below equal cannot be negated");
73 }
74 ShouldNotReachHere();
75 return eql;
76 }
77
78 void Instruction::update_exception_state(ValueStack* state) {
79 if (state != nullptr && (state->kind() == ValueStack::EmptyExceptionState || state->kind() == ValueStack::ExceptionState)) {
80 assert(state->kind() == ValueStack::EmptyExceptionState || Compilation::current()->env()->should_retain_local_variables(), "unexpected state kind");
81 _exception_state = state;
82 } else {
83 _exception_state = nullptr;
84 }
85 }
86
87 // Prev without need to have BlockBegin
88 Instruction* Instruction::prev() {
89 Instruction* p = nullptr;
90 Instruction* q = block();
91 while (q != this) {
92 assert(q != nullptr, "this is not in the block's instruction list");
93 p = q; q = q->next();
94 }
95 return p;
96 }
97
98
99 void Instruction::state_values_do(ValueVisitor* f) {
100 if (state_before() != nullptr) {
101 state_before()->values_do(f);
102 }
103 if (exception_state() != nullptr) {
104 exception_state()->values_do(f);
105 }
106 }
107
108 ciType* Instruction::exact_type() const {
109 ciType* t = declared_type();
110 if (t != nullptr && t->is_klass()) {
111 return t->as_klass()->exact_klass();
112 }
113 return nullptr;
114 }
115
116
117 #ifndef PRODUCT
118 void Instruction::check_state(ValueStack* state) {
119 if (state != nullptr) {
120 state->verify();
121 }
122 }
123
124
125 void Instruction::print() {
126 InstructionPrinter ip;
127 print(ip);
128 }
129
130
131 void Instruction::print_line() {
132 InstructionPrinter ip;
133 ip.print_line(this);
134 }
135
136
137 void Instruction::print(InstructionPrinter& ip) {
138 ip.print_head();
139 ip.print_line(this);
140 tty->cr();
141 }
142 #endif // PRODUCT
143
144
145 // perform constant and interval tests on index value
146 bool AccessIndexed::compute_needs_range_check() {
147 if (length()) {
148 Constant* clength = length()->as_Constant();
149 Constant* cindex = index()->as_Constant();
150 if (clength && cindex) {
151 IntConstant* l = clength->type()->as_IntConstant();
152 IntConstant* i = cindex->type()->as_IntConstant();
153 if (l && i && i->value() < l->value() && i->value() >= 0) {
154 return false;
155 }
156 }
157 }
158
159 if (!this->check_flag(NeedsRangeCheckFlag)) {
160 return false;
161 }
162
163 return true;
164 }
165
166
167 ciType* Constant::exact_type() const {
168 if (type()->is_object() && type()->as_ObjectType()->is_loaded()) {
169 return type()->as_ObjectType()->exact_type();
170 }
171 return nullptr;
172 }
173
174 ciType* LoadIndexed::exact_type() const {
175 ciType* array_type = array()->exact_type();
176 if (array_type != nullptr) {
177 assert(array_type->is_array_klass(), "what else?");
178 ciArrayKlass* ak = (ciArrayKlass*)array_type;
179
180 if (ak->element_type()->is_instance_klass()) {
181 ciInstanceKlass* ik = (ciInstanceKlass*)ak->element_type();
182 if (ik->is_loaded() && ik->is_final()) {
183 return ik;
184 }
185 }
186 }
187 return Instruction::exact_type();
188 }
189
190
191 ciType* LoadIndexed::declared_type() const {
192 ciType* array_type = array()->declared_type();
193 if (array_type == nullptr || !array_type->is_loaded()) {
194 return nullptr;
195 }
196 assert(array_type->is_array_klass(), "what else?");
197 ciArrayKlass* ak = (ciArrayKlass*)array_type;
198 return ak->element_type();
199 }
200
201
202 ciType* LoadField::declared_type() const {
203 return field()->type();
204 }
205
206
207 ciType* NewTypeArray::exact_type() const {
208 return ciTypeArrayKlass::make(elt_type());
209 }
210
211 ciType* NewObjectArray::exact_type() const {
212 return ciObjArrayKlass::make(klass());
213 }
214
215 ciType* NewArray::declared_type() const {
216 return exact_type();
217 }
218
219 ciType* NewInstance::exact_type() const {
220 return klass();
221 }
222
223 ciType* NewInstance::declared_type() const {
224 return exact_type();
225 }
226
227 ciType* CheckCast::declared_type() const {
228 return klass();
229 }
230
231 // Implementation of ArithmeticOp
232
233 bool ArithmeticOp::is_commutative() const {
234 switch (op()) {
235 case Bytecodes::_iadd: // fall through
236 case Bytecodes::_ladd: // fall through
237 case Bytecodes::_fadd: // fall through
238 case Bytecodes::_dadd: // fall through
239 case Bytecodes::_imul: // fall through
240 case Bytecodes::_lmul: // fall through
241 case Bytecodes::_fmul: // fall through
242 case Bytecodes::_dmul: return true;
243 default : return false;
244 }
245 }
246
247
248 bool ArithmeticOp::can_trap() const {
249 switch (op()) {
250 case Bytecodes::_idiv: // fall through
251 case Bytecodes::_ldiv: // fall through
252 case Bytecodes::_irem: // fall through
253 case Bytecodes::_lrem: return true;
254 default : return false;
255 }
256 }
257
258
259 // Implementation of LogicOp
260
261 bool LogicOp::is_commutative() const {
262 #ifdef ASSERT
263 switch (op()) {
264 case Bytecodes::_iand: // fall through
265 case Bytecodes::_land: // fall through
266 case Bytecodes::_ior : // fall through
267 case Bytecodes::_lor : // fall through
268 case Bytecodes::_ixor: // fall through
269 case Bytecodes::_lxor: break;
270 default : ShouldNotReachHere(); break;
271 }
272 #endif
273 // all LogicOps are commutative
274 return true;
275 }
276
277
278 // Implementation of IfOp
279
280 bool IfOp::is_commutative() const {
281 return cond() == eql || cond() == neq;
282 }
283
284
285 // Implementation of StateSplit
286
287 void StateSplit::substitute(BlockList& list, BlockBegin* old_block, BlockBegin* new_block) {
288 NOT_PRODUCT(bool assigned = false;)
289 for (int i = 0; i < list.length(); i++) {
290 BlockBegin** b = list.adr_at(i);
291 if (*b == old_block) {
292 *b = new_block;
293 NOT_PRODUCT(assigned = true;)
294 }
295 }
296 assert(assigned == true, "should have assigned at least once");
297 }
298
299
300 IRScope* StateSplit::scope() const {
301 return _state->scope();
302 }
303
304
305 void StateSplit::state_values_do(ValueVisitor* f) {
306 Instruction::state_values_do(f);
307 if (state() != nullptr) state()->values_do(f);
308 }
309
310
311 void BlockBegin::state_values_do(ValueVisitor* f) {
312 StateSplit::state_values_do(f);
313
314 if (is_set(BlockBegin::exception_entry_flag)) {
315 for (int i = 0; i < number_of_exception_states(); i++) {
316 exception_state_at(i)->values_do(f);
317 }
318 }
319 }
320
321
322 // Implementation of Invoke
323
324
325 Invoke::Invoke(Bytecodes::Code code, ValueType* result_type, Value recv, Values* args,
326 ciMethod* target, ValueStack* state_before)
327 : StateSplit(result_type, state_before)
328 , _code(code)
329 , _recv(recv)
330 , _args(args)
331 , _target(target)
332 {
333 set_flag(TargetIsLoadedFlag, target->is_loaded());
334 set_flag(TargetIsFinalFlag, target_is_loaded() && target->is_final_method());
335
336 assert(args != nullptr, "args must exist");
337 #ifdef ASSERT
338 AssertValues assert_value;
339 values_do(&assert_value);
340 #endif
341
342 // provide an initial guess of signature size.
343 _signature = new BasicTypeList(number_of_arguments() + (has_receiver() ? 1 : 0));
344 if (has_receiver()) {
345 _signature->append(as_BasicType(receiver()->type()));
346 }
347 for (int i = 0; i < number_of_arguments(); i++) {
348 ValueType* t = argument_at(i)->type();
349 BasicType bt = as_BasicType(t);
350 _signature->append(bt);
351 }
352 }
353
354
355 void Invoke::state_values_do(ValueVisitor* f) {
356 StateSplit::state_values_do(f);
357 if (state_before() != nullptr) state_before()->values_do(f);
358 if (state() != nullptr) state()->values_do(f);
359 }
360
361 ciType* Invoke::declared_type() const {
362 ciSignature* declared_signature = state()->scope()->method()->get_declared_signature_at_bci(state()->bci());
363 ciType *t = declared_signature->return_type();
364 assert(t->basic_type() != T_VOID, "need return value of void method?");
365 return t;
366 }
367
368 // Implementation of Constant
369 intx Constant::hash() const {
370 if (state_before() == nullptr) {
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() == nullptr) 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 != nullptr && t2 != nullptr &&
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 != nullptr && t2 != nullptr &&
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 != nullptr && t2 != nullptr &&
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 != nullptr && t2 != nullptr &&
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 != nullptr && t2 != nullptr &&
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 != nullptr && t2 != nullptr &&
446 t1->is_loaded() && t2->is_loaded() &&
447 t1->constant_value() == t2->constant_value());
448 }
449 default:
450 return false;
451 }
452 }
453
454 Constant::CompareResult Constant::compare(Instruction::Condition cond, Value right) const {
455 Constant* rc = right->as_Constant();
456 // other is not a constant
457 if (rc == nullptr) return not_comparable;
458
459 ValueType* lt = type();
460 ValueType* rt = rc->type();
461 // different types
462 if (lt->base() != rt->base()) return not_comparable;
463 switch (lt->tag()) {
464 case intTag: {
465 int x = lt->as_IntConstant()->value();
466 int y = rt->as_IntConstant()->value();
467 switch (cond) {
468 case If::eql: return x == y ? cond_true : cond_false;
469 case If::neq: return x != y ? cond_true : cond_false;
470 case If::lss: return x < y ? cond_true : cond_false;
471 case If::leq: return x <= y ? cond_true : cond_false;
472 case If::gtr: return x > y ? cond_true : cond_false;
473 case If::geq: return x >= y ? cond_true : cond_false;
474 default : break;
475 }
476 break;
477 }
478 case longTag: {
479 jlong x = lt->as_LongConstant()->value();
480 jlong y = rt->as_LongConstant()->value();
481 switch (cond) {
482 case If::eql: return x == y ? cond_true : cond_false;
483 case If::neq: return x != y ? cond_true : cond_false;
484 case If::lss: return x < y ? cond_true : cond_false;
485 case If::leq: return x <= y ? cond_true : cond_false;
486 case If::gtr: return x > y ? cond_true : cond_false;
487 case If::geq: return x >= y ? cond_true : cond_false;
488 default : break;
489 }
490 break;
491 }
492 case objectTag: {
493 ciObject* xvalue = lt->as_ObjectType()->constant_value();
494 ciObject* yvalue = rt->as_ObjectType()->constant_value();
495 assert(xvalue != nullptr && yvalue != nullptr, "not constants");
496 if (xvalue->is_loaded() && yvalue->is_loaded()) {
497 switch (cond) {
498 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
499 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
500 default : break;
501 }
502 }
503 break;
504 }
505 case metaDataTag: {
506 ciMetadata* xvalue = lt->as_MetadataType()->constant_value();
507 ciMetadata* yvalue = rt->as_MetadataType()->constant_value();
508 assert(xvalue != nullptr && yvalue != nullptr, "not constants");
509 if (xvalue->is_loaded() && yvalue->is_loaded()) {
510 switch (cond) {
511 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
512 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
513 default : break;
514 }
515 }
516 break;
517 }
518 default:
519 break;
520 }
521 return not_comparable;
522 }
523
524
525 // Implementation of BlockBegin
526
527 void BlockBegin::set_end(BlockEnd* new_end) { // Assumes that no predecessor of new_end still has it as its successor
528 assert(new_end != nullptr, "Should not reset block new_end to null");
529 if (new_end == _end) return;
530
531 // Remove this block as predecessor of its current successors
532 if (_end != nullptr) {
533 for (int i = 0; i < number_of_sux(); i++) {
534 sux_at(i)->remove_predecessor(this);
535 }
536 }
537
538 _end = new_end;
539
540 // Add this block as predecessor of its new successors
541 for (int i = 0; i < number_of_sux(); i++) {
542 sux_at(i)->add_predecessor(this);
543 }
544 }
545
546
547 void BlockBegin::disconnect_edge(BlockBegin* from, BlockBegin* to) {
548 // disconnect any edges between from and to
549 #ifndef PRODUCT
550 if (PrintIR && Verbose) {
551 tty->print_cr("Disconnected edge B%d -> B%d", from->block_id(), to->block_id());
552 }
553 #endif
554 for (int s = 0; s < from->number_of_sux();) {
555 BlockBegin* sux = from->sux_at(s);
556 if (sux == to) {
557 int index = sux->_predecessors.find(from);
558 if (index >= 0) {
559 sux->_predecessors.remove_at(index);
560 }
561 from->end()->remove_sux_at(s);
562 } else {
563 s++;
564 }
565 }
566 }
567
568
569 void BlockBegin::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
570 // modify predecessors before substituting successors
571 for (int i = 0; i < number_of_sux(); i++) {
572 if (sux_at(i) == old_sux) {
573 // remove old predecessor before adding new predecessor
574 // otherwise there is a dead predecessor in the list
575 new_sux->remove_predecessor(old_sux);
576 new_sux->add_predecessor(this);
577 }
578 }
579 old_sux->remove_predecessor(this);
580 end()->substitute_sux(old_sux, new_sux);
581 }
582
583
584
585 // In general it is not possible to calculate a value for the field "depth_first_number"
586 // of the inserted block, without recomputing the values of the other blocks
587 // in the CFG. Therefore the value of "depth_first_number" in BlockBegin becomes meaningless.
588 BlockBegin* BlockBegin::insert_block_between(BlockBegin* sux) {
589 assert(!sux->is_set(critical_edge_split_flag), "sanity check");
590
591 int bci = sux->bci();
592 // critical edge splitting may introduce a goto after a if and array
593 // bound check elimination may insert a predicate between the if and
594 // goto. The bci of the goto can't be the one of the if otherwise
595 // the state and bci are inconsistent and a deoptimization triggered
596 // by the predicate would lead to incorrect execution/a crash.
597 BlockBegin* new_sux = new BlockBegin(bci);
598
599 // mark this block (special treatment when block order is computed)
600 new_sux->set(critical_edge_split_flag);
601
602 // This goto is not a safepoint.
603 Goto* e = new Goto(sux, false);
604 new_sux->set_next(e, bci);
605 new_sux->set_end(e);
606 // setup states
607 ValueStack* s = end()->state();
608 new_sux->set_state(s->copy(s->kind(), bci));
609 e->set_state(s->copy(s->kind(), bci));
610 assert(new_sux->state()->locals_size() == s->locals_size(), "local size mismatch!");
611 assert(new_sux->state()->stack_size() == s->stack_size(), "stack size mismatch!");
612 assert(new_sux->state()->locks_size() == s->locks_size(), "locks size mismatch!");
613
614 // link predecessor to new block
615 end()->substitute_sux(sux, new_sux);
616
617 // The ordering needs to be the same, so remove the link that the
618 // set_end call above added and substitute the new_sux for this
619 // block.
620 sux->remove_predecessor(new_sux);
621
622 // the successor could be the target of a switch so it might have
623 // multiple copies of this predecessor, so substitute the new_sux
624 // for the first and delete the rest.
625 bool assigned = false;
626 BlockList& list = sux->_predecessors;
627 for (int i = 0; i < list.length(); i++) {
628 BlockBegin** b = list.adr_at(i);
629 if (*b == this) {
630 if (assigned) {
631 list.remove_at(i);
632 // reprocess this index
633 i--;
634 } else {
635 assigned = true;
636 *b = new_sux;
637 }
638 // link the new block back to it's predecessors.
639 new_sux->add_predecessor(this);
640 }
641 }
642 assert(assigned == true, "should have assigned at least once");
643 return new_sux;
644 }
645
646
647 void BlockBegin::add_predecessor(BlockBegin* pred) {
648 _predecessors.append(pred);
649 }
650
651
652 void BlockBegin::remove_predecessor(BlockBegin* pred) {
653 int idx;
654 while ((idx = _predecessors.find(pred)) >= 0) {
655 _predecessors.remove_at(idx);
656 }
657 }
658
659
660 void BlockBegin::add_exception_handler(BlockBegin* b) {
661 assert(b != nullptr && (b->is_set(exception_entry_flag)), "exception handler must exist");
662 // add only if not in the list already
663 if (!_exception_handlers.contains(b)) _exception_handlers.append(b);
664 }
665
666 int BlockBegin::add_exception_state(ValueStack* state) {
667 assert(is_set(exception_entry_flag), "only for xhandlers");
668 if (_exception_states == nullptr) {
669 _exception_states = new ValueStackStack(4);
670 }
671 _exception_states->append(state);
672 return _exception_states->length() - 1;
673 }
674
675
676 void BlockBegin::iterate_preorder(boolArray& mark, BlockClosure* closure) {
677 if (!mark.at(block_id())) {
678 mark.at_put(block_id(), true);
679 closure->block_do(this);
680 BlockEnd* e = end(); // must do this after block_do because block_do may change it!
681 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_preorder(mark, closure); }
682 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_preorder(mark, closure); }
683 }
684 }
685
686
687 void BlockBegin::iterate_postorder(boolArray& mark, BlockClosure* closure) {
688 if (!mark.at(block_id())) {
689 mark.at_put(block_id(), true);
690 BlockEnd* e = end();
691 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_postorder(mark, closure); }
692 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_postorder(mark, closure); }
693 closure->block_do(this);
694 }
695 }
696
697
698 void BlockBegin::iterate_preorder(BlockClosure* closure) {
699 int mark_len = number_of_blocks();
700 boolArray mark(mark_len, mark_len, false);
701 iterate_preorder(mark, closure);
702 }
703
704
705 void BlockBegin::iterate_postorder(BlockClosure* closure) {
706 int mark_len = number_of_blocks();
707 boolArray mark(mark_len, mark_len, false);
708 iterate_postorder(mark, closure);
709 }
710
711
712 void BlockBegin::block_values_do(ValueVisitor* f) {
713 for (Instruction* n = this; n != nullptr; n = n->next()) n->values_do(f);
714 }
715
716
717 #ifndef PRODUCT
718 #define TRACE_PHI(code) if (PrintPhiFunctions) { code; }
719 #else
720 #define TRACE_PHI(coce)
721 #endif
722
723
724 bool BlockBegin::try_merge(ValueStack* new_state, bool has_irreducible_loops) {
725 TRACE_PHI(tty->print_cr("********** try_merge for block B%d", block_id()));
726
727 // local variables used for state iteration
728 int index;
729 Value new_value, existing_value;
730
731 ValueStack* existing_state = state();
732 if (existing_state == nullptr) {
733 TRACE_PHI(tty->print_cr("first call of try_merge for this block"));
734
735 if (is_set(BlockBegin::was_visited_flag)) {
736 // this actually happens for complicated jsr/ret structures
737 return false; // BAILOUT in caller
738 }
739
740 // copy state because it is altered
741 new_state = new_state->copy(ValueStack::BlockBeginState, bci());
742
743 // Use method liveness to invalidate dead locals
744 MethodLivenessResult liveness = new_state->scope()->method()->liveness_at_bci(bci());
745 if (liveness.is_valid()) {
746 assert((int)liveness.size() == new_state->locals_size(), "error in use of liveness");
747
748 for_each_local_value(new_state, index, new_value) {
749 if (!liveness.at(index) || new_value->type()->is_illegal()) {
750 new_state->invalidate_local(index);
751 TRACE_PHI(tty->print_cr("invalidating dead local %d", index));
752 }
753 }
754 }
755
756 if (is_set(BlockBegin::parser_loop_header_flag)) {
757 TRACE_PHI(tty->print_cr("loop header block, initializing phi functions"));
758
759 for_each_stack_value(new_state, index, new_value) {
760 new_state->setup_phi_for_stack(this, index);
761 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));
762 }
763
764 BitMap& requires_phi_function = new_state->scope()->requires_phi_function();
765 for_each_local_value(new_state, index, new_value) {
766 bool requires_phi = requires_phi_function.at(index) || (new_value->type()->is_double_word() && requires_phi_function.at(index + 1));
767 if (requires_phi || !SelectivePhiFunctions || has_irreducible_loops) {
768 new_state->setup_phi_for_local(this, index);
769 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));
770 }
771 }
772 }
773
774 // initialize state of block
775 set_state(new_state);
776
777 } else if (existing_state->is_same(new_state)) {
778 TRACE_PHI(tty->print_cr("existing state found"));
779
780 assert(existing_state->scope() == new_state->scope(), "not matching");
781 assert(existing_state->locals_size() == new_state->locals_size(), "not matching");
782 assert(existing_state->stack_size() == new_state->stack_size(), "not matching");
783
784 if (is_set(BlockBegin::was_visited_flag)) {
785 TRACE_PHI(tty->print_cr("loop header block, phis must be present"));
786
787 if (!is_set(BlockBegin::parser_loop_header_flag)) {
788 // this actually happens for complicated jsr/ret structures
789 return false; // BAILOUT in caller
790 }
791
792 for_each_local_value(existing_state, index, existing_value) {
793 Value new_value = new_state->local_at(index);
794 if (new_value == nullptr || new_value->type()->tag() != existing_value->type()->tag()) {
795 Phi* existing_phi = existing_value->as_Phi();
796 if (existing_phi == nullptr) {
797 return false; // BAILOUT in caller
798 }
799 // Invalidate the phi function here. This case is very rare except for
800 // JVMTI capability "can_access_local_variables".
801 // In really rare cases we will bail out in LIRGenerator::move_to_phi.
802 existing_phi->make_illegal();
803 existing_state->invalidate_local(index);
804 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
805 }
806
807 if (existing_value != new_state->local_at(index) && existing_value->as_Phi() == nullptr) {
808 TRACE_PHI(tty->print_cr("required phi for local %d is missing, irreducible loop?", index));
809 return false; // BAILOUT in caller
810 }
811 }
812
813 #ifdef ASSERT
814 // check that all necessary phi functions are present
815 for_each_stack_value(existing_state, index, existing_value) {
816 assert(existing_value->as_Phi() != nullptr && existing_value->as_Phi()->block() == this, "phi function required");
817 }
818 for_each_local_value(existing_state, index, existing_value) {
819 assert(existing_value == new_state->local_at(index) || (existing_value->as_Phi() != nullptr && existing_value->as_Phi()->as_Phi()->block() == this), "phi function required");
820 }
821 #endif
822
823 } else {
824 TRACE_PHI(tty->print_cr("creating phi functions on demand"));
825
826 // create necessary phi functions for stack
827 for_each_stack_value(existing_state, index, existing_value) {
828 Value new_value = new_state->stack_at(index);
829 Phi* existing_phi = existing_value->as_Phi();
830
831 if (new_value != existing_value && (existing_phi == nullptr || existing_phi->block() != this)) {
832 existing_state->setup_phi_for_stack(this, index);
833 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));
834 }
835 }
836
837 // create necessary phi functions for locals
838 for_each_local_value(existing_state, index, existing_value) {
839 Value new_value = new_state->local_at(index);
840 Phi* existing_phi = existing_value->as_Phi();
841
842 if (new_value == nullptr || new_value->type()->tag() != existing_value->type()->tag()) {
843 existing_state->invalidate_local(index);
844 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
845 } else if (new_value != existing_value && (existing_phi == nullptr || existing_phi->block() != this)) {
846 existing_state->setup_phi_for_local(this, index);
847 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));
848 }
849 }
850 }
851
852 assert(existing_state->caller_state() == new_state->caller_state(), "caller states must be equal");
853
854 } else {
855 assert(false, "stack or locks not matching (invalid bytecodes)");
856 return false;
857 }
858
859 TRACE_PHI(tty->print_cr("********** try_merge for block B%d successful", block_id()));
860
861 return true;
862 }
863
864
865 #ifndef PRODUCT
866 void BlockBegin::print_block() {
867 InstructionPrinter ip;
868 print_block(ip, false);
869 }
870
871
872 void BlockBegin::print_block(InstructionPrinter& ip, bool live_only) {
873 ip.print_instr(this); tty->cr();
874 ip.print_stack(this->state()); tty->cr();
875 ip.print_inline_level(this);
876 ip.print_head();
877 for (Instruction* n = next(); n != nullptr; n = n->next()) {
878 if (!live_only || n->is_pinned() || n->use_count() > 0) {
879 ip.print_line(n);
880 }
881 }
882 tty->cr();
883 }
884 #endif // PRODUCT
885
886
887 // Implementation of BlockList
888
889 void BlockList::iterate_forward (BlockClosure* closure) {
890 const int l = length();
891 for (int i = 0; i < l; i++) closure->block_do(at(i));
892 }
893
894
895 void BlockList::iterate_backward(BlockClosure* closure) {
896 for (int i = length() - 1; i >= 0; i--) closure->block_do(at(i));
897 }
898
899
900 void BlockList::values_do(ValueVisitor* f) {
901 for (int i = length() - 1; i >= 0; i--) at(i)->block_values_do(f);
902 }
903
904
905 #ifndef PRODUCT
906 void BlockList::print(bool cfg_only, bool live_only) {
907 InstructionPrinter ip;
908 for (int i = 0; i < length(); i++) {
909 BlockBegin* block = at(i);
910 if (cfg_only) {
911 ip.print_instr(block); tty->cr();
912 } else {
913 block->print_block(ip, live_only);
914 }
915 }
916 }
917 #endif // PRODUCT
918
919
920 // Implementation of BlockEnd
921
922 void BlockEnd::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
923 substitute(*_sux, old_sux, new_sux);
924 }
925
926 // Implementation of Phi
927
928 // Normal phi functions take their operands from the last instruction of the
929 // predecessor. Special handling is needed for xhanlder entries because there
930 // the state of arbitrary instructions are needed.
931
932 Value Phi::operand_at(int i) const {
933 ValueStack* state;
934 if (_block->is_set(BlockBegin::exception_entry_flag)) {
935 state = _block->exception_state_at(i);
936 } else {
937 state = _block->pred_at(i)->end()->state();
938 }
939 assert(state != nullptr, "");
940
941 if (is_local()) {
942 return state->local_at(local_index());
943 } else {
944 return state->stack_at(stack_index());
945 }
946 }
947
948
949 int Phi::operand_count() const {
950 if (_block->is_set(BlockBegin::exception_entry_flag)) {
951 return _block->number_of_exception_states();
952 } else {
953 return _block->number_of_preds();
954 }
955 }
956
957 #ifdef ASSERT
958 // Constructor of Assert
959 Assert::Assert(Value x, Condition cond, bool unordered_is_true, Value y) : Instruction(illegalType)
960 , _x(x)
961 , _cond(cond)
962 , _y(y)
963 {
964 set_flag(UnorderedIsTrueFlag, unordered_is_true);
965 assert(x->type()->tag() == y->type()->tag(), "types must match");
966 pin();
967
968 stringStream strStream;
969 Compilation::current()->method()->print_name(&strStream);
970
971 stringStream strStream1;
972 InstructionPrinter ip1(1, &strStream1);
973 ip1.print_instr(x);
974
975 stringStream strStream2;
976 InstructionPrinter ip2(1, &strStream2);
977 ip2.print_instr(y);
978
979 stringStream ss;
980 ss.print("Assertion %s %s %s in method %s", strStream1.freeze(), ip2.cond_name(cond), strStream2.freeze(), strStream.freeze());
981
982 _message = ss.as_string();
983 }
984 #endif
985
986 void RangeCheckPredicate::check_state() {
987 assert(state()->kind() != ValueStack::EmptyExceptionState && state()->kind() != ValueStack::ExceptionState, "will deopt with empty state");
988 }
989
990 void ProfileInvoke::state_values_do(ValueVisitor* f) {
991 if (state() != nullptr) state()->values_do(f);
992 }