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/ciFlatArrayKlass.hpp"
30 #include "ci/ciInlineKlass.hpp"
31 #include "ci/ciObjArrayKlass.hpp"
32 #include "ci/ciTypeArrayKlass.hpp"
33 #include "utilities/bitMap.inline.hpp"
34
35
36 // Implementation of Instruction
37
38
39 int Instruction::dominator_depth() {
40 int result = -1;
41 if (block()) {
42 result = block()->dominator_depth();
43 }
44 assert(result != -1 || this->as_Local(), "Only locals have dominator depth -1");
45 return result;
46 }
47
48 Instruction::Condition Instruction::mirror(Condition cond) {
49 switch (cond) {
50 case eql: return eql;
51 case neq: return neq;
52 case lss: return gtr;
53 case leq: return geq;
54 case gtr: return lss;
55 case geq: return leq;
56 case aeq: return beq;
57 case beq: return aeq;
58 }
59 ShouldNotReachHere();
60 return eql;
61 }
62
63
64 Instruction::Condition Instruction::negate(Condition cond) {
65 switch (cond) {
66 case eql: return neq;
67 case neq: return eql;
68 case lss: return geq;
69 case leq: return gtr;
70 case gtr: return leq;
71 case geq: return lss;
72 case aeq: assert(false, "Above equal cannot be negated");
73 case beq: assert(false, "Below equal cannot be negated");
74 }
75 ShouldNotReachHere();
76 return eql;
77 }
78
79 void Instruction::update_exception_state(ValueStack* state) {
80 if (state != nullptr && (state->kind() == ValueStack::EmptyExceptionState || state->kind() == ValueStack::ExceptionState)) {
81 assert(state->kind() == ValueStack::EmptyExceptionState || Compilation::current()->env()->should_retain_local_variables(), "unexpected state kind");
82 _exception_state = state;
83 } else {
84 _exception_state = nullptr;
85 }
86 }
87
88 // Prev without need to have BlockBegin
89 Instruction* Instruction::prev() {
90 Instruction* p = nullptr;
91 Instruction* q = block();
92 while (q != this) {
93 assert(q != nullptr, "this is not in the block's instruction list");
94 p = q; q = q->next();
95 }
96 return p;
97 }
98
99
100 void Instruction::state_values_do(ValueVisitor* f) {
101 if (state_before() != nullptr) {
102 state_before()->values_do(f);
103 }
104 if (exception_state() != nullptr) {
105 exception_state()->values_do(f);
106 }
107 }
108
109 ciType* Instruction::exact_type() const {
110 ciType* t = declared_type();
111 if (t != nullptr && t->is_klass()) {
112 return t->as_klass()->exact_klass();
113 }
114 return nullptr;
115 }
116
117 ciKlass* Instruction::as_loaded_klass_or_null() const {
118 ciType* type = declared_type();
119 if (type != nullptr && type->is_klass()) {
120 ciKlass* klass = type->as_klass();
121 if (klass->is_loaded()) {
122 return klass;
123 }
124 }
125 return nullptr;
126 }
127
128 bool Instruction::is_loaded_flat_array() const {
129 if (UseArrayFlattening) {
130 ciType* type = declared_type();
131 return type != nullptr && type->is_flat_array_klass();
132 }
133 return false;
134 }
135
136 bool Instruction::maybe_flat_array() {
137 if (UseArrayFlattening) {
138 ciType* type = declared_type();
139 if (type != nullptr) {
140 if (type->is_obj_array_klass()) {
141 // Due to array covariance, the runtime type might be a flat array.
142 ciKlass* element_klass = type->as_obj_array_klass()->element_klass();
143 if (element_klass->can_be_inline_klass() && (!element_klass->is_inlinetype() || element_klass->as_inline_klass()->flat_in_array())) {
144 return true;
145 }
146 } else if (type->is_flat_array_klass()) {
147 return true;
148 } else if (type->is_klass() && type->as_klass()->is_java_lang_Object()) {
149 // This can happen as a parameter to System.arraycopy()
150 return true;
151 }
152 } else {
153 // Type info gets lost during Phi merging (Phi, IfOp, etc), but we might be storing into a
154 // flat array, so we should do a runtime check.
155 return true;
156 }
157 }
158 return false;
159 }
160
161 bool Instruction::maybe_null_free_array() {
162 ciType* type = declared_type();
163 if (type != nullptr) {
164 if (type->is_obj_array_klass()) {
165 // Due to array covariance, the runtime type might be a null-free array.
166 if (type->as_obj_array_klass()->can_be_inline_array_klass()) {
167 return true;
168 }
169 }
170 } else {
171 // Type info gets lost during Phi merging (Phi, IfOp, etc), but we might be storing into a
172 // null-free array, so we should do a runtime check.
173 return true;
174 }
175 return false;
176 }
177
178 #ifndef PRODUCT
179 void Instruction::check_state(ValueStack* state) {
180 if (state != nullptr) {
181 state->verify();
182 }
183 }
184
185
186 void Instruction::print() {
187 InstructionPrinter ip;
188 print(ip);
189 }
190
191
192 void Instruction::print_line() {
193 InstructionPrinter ip;
194 ip.print_line(this);
195 }
196
197
198 void Instruction::print(InstructionPrinter& ip) {
199 ip.print_head();
200 ip.print_line(this);
201 tty->cr();
202 }
203 #endif // PRODUCT
204
205
206 // perform constant and interval tests on index value
207 bool AccessIndexed::compute_needs_range_check() {
208 if (length()) {
209 Constant* clength = length()->as_Constant();
210 Constant* cindex = index()->as_Constant();
211 if (clength && cindex) {
212 IntConstant* l = clength->type()->as_IntConstant();
213 IntConstant* i = cindex->type()->as_IntConstant();
214 if (l && i && i->value() < l->value() && i->value() >= 0) {
215 return false;
216 }
217 }
218 }
219
220 if (!this->check_flag(NeedsRangeCheckFlag)) {
221 return false;
222 }
223
224 return true;
225 }
226
227
228 ciType* Constant::exact_type() const {
229 if (type()->is_object() && type()->as_ObjectType()->is_loaded()) {
230 return type()->as_ObjectType()->exact_type();
231 }
232 return nullptr;
233 }
234
235 ciType* LoadIndexed::exact_type() const {
236 ciType* array_type = array()->exact_type();
237 if (delayed() == nullptr && array_type != nullptr) {
238 assert(array_type->is_array_klass(), "what else?");
239 ciArrayKlass* ak = (ciArrayKlass*)array_type;
240
241 if (ak->element_type()->is_instance_klass()) {
242 ciInstanceKlass* ik = (ciInstanceKlass*)ak->element_type();
243 if (ik->is_loaded() && ik->is_final()) {
244 return ik;
245 }
246 }
247 }
248 return Instruction::exact_type();
249 }
250
251 ciType* LoadIndexed::declared_type() const {
252 if (delayed() != nullptr) {
253 return delayed()->field()->type();
254 }
255 ciType* array_type = array()->declared_type();
256 if (array_type == nullptr || !array_type->is_loaded()) {
257 return nullptr;
258 }
259 assert(array_type->is_array_klass(), "what else?");
260 ciArrayKlass* ak = (ciArrayKlass*)array_type;
261 return ak->element_type();
262 }
263
264 bool StoreIndexed::is_exact_flat_array_store() const {
265 if (array()->is_loaded_flat_array() && value()->as_Constant() == nullptr && value()->declared_type() != nullptr) {
266 ciKlass* element_klass = array()->declared_type()->as_flat_array_klass()->element_klass();
267 ciKlass* actual_klass = value()->declared_type()->as_klass();
268
269 // The following check can fail with inlining:
270 // void test45_inline(Object[] oa, Object o, int index) { oa[index] = o; }
271 // void test45(MyValue1[] va, int index, MyValue2 v) { test45_inline(va, v, index); }
272 if (element_klass == actual_klass) {
273 return true;
274 }
275 }
276 return false;
277 }
278
279 ciType* LoadField::declared_type() const {
280 return field()->type();
281 }
282
283
284 ciType* NewTypeArray::exact_type() const {
285 return ciTypeArrayKlass::make(elt_type());
286 }
287
288 ciType* NewObjectArray::exact_type() const {
289 return ciArrayKlass::make(klass());
290 }
291
292 ciType* NewMultiArray::exact_type() const {
293 return _klass;
294 }
295
296 ciType* NewArray::declared_type() const {
297 return exact_type();
298 }
299
300 ciType* NewInstance::exact_type() const {
301 return klass();
302 }
303
304 ciType* NewInstance::declared_type() const {
305 return exact_type();
306 }
307
308 ciType* CheckCast::declared_type() const {
309 return klass();
310 }
311
312 // Implementation of ArithmeticOp
313
314 bool ArithmeticOp::is_commutative() const {
315 switch (op()) {
316 case Bytecodes::_iadd: // fall through
317 case Bytecodes::_ladd: // fall through
318 case Bytecodes::_fadd: // fall through
319 case Bytecodes::_dadd: // fall through
320 case Bytecodes::_imul: // fall through
321 case Bytecodes::_lmul: // fall through
322 case Bytecodes::_fmul: // fall through
323 case Bytecodes::_dmul: return true;
324 default : return false;
325 }
326 }
327
328
329 bool ArithmeticOp::can_trap() const {
330 switch (op()) {
331 case Bytecodes::_idiv: // fall through
332 case Bytecodes::_ldiv: // fall through
333 case Bytecodes::_irem: // fall through
334 case Bytecodes::_lrem: return true;
335 default : return false;
336 }
337 }
338
339
340 // Implementation of LogicOp
341
342 bool LogicOp::is_commutative() const {
343 #ifdef ASSERT
344 switch (op()) {
345 case Bytecodes::_iand: // fall through
346 case Bytecodes::_land: // fall through
347 case Bytecodes::_ior : // fall through
348 case Bytecodes::_lor : // fall through
349 case Bytecodes::_ixor: // fall through
350 case Bytecodes::_lxor: break;
351 default : ShouldNotReachHere(); break;
352 }
353 #endif
354 // all LogicOps are commutative
355 return true;
356 }
357
358
359 // Implementation of IfOp
360
361 bool IfOp::is_commutative() const {
362 return cond() == eql || cond() == neq;
363 }
364
365
366 // Implementation of StateSplit
367
368 void StateSplit::substitute(BlockList& list, BlockBegin* old_block, BlockBegin* new_block) {
369 NOT_PRODUCT(bool assigned = false;)
370 for (int i = 0; i < list.length(); i++) {
371 BlockBegin** b = list.adr_at(i);
372 if (*b == old_block) {
373 *b = new_block;
374 NOT_PRODUCT(assigned = true;)
375 }
376 }
377 assert(assigned == true, "should have assigned at least once");
378 }
379
380
381 IRScope* StateSplit::scope() const {
382 return _state->scope();
383 }
384
385
386 void StateSplit::state_values_do(ValueVisitor* f) {
387 Instruction::state_values_do(f);
388 if (state() != nullptr) state()->values_do(f);
389 }
390
391
392 void BlockBegin::state_values_do(ValueVisitor* f) {
393 StateSplit::state_values_do(f);
394
395 if (is_set(BlockBegin::exception_entry_flag)) {
396 for (int i = 0; i < number_of_exception_states(); i++) {
397 exception_state_at(i)->values_do(f);
398 }
399 }
400 }
401
402
403 StoreField::StoreField(Value obj, int offset, ciField* field, Value value, bool is_static,
404 ValueStack* state_before, bool needs_patching)
405 : AccessField(obj, offset, field, is_static, state_before, needs_patching)
406 , _value(value)
407 , _enclosing_field(nullptr)
408 {
409 #ifdef ASSERT
410 AssertValues assert_value;
411 values_do(&assert_value);
412 #endif
413 pin();
414 }
415
416 StoreIndexed::StoreIndexed(Value array, Value index, Value length, BasicType elt_type, Value value,
417 ValueStack* state_before, bool check_boolean, bool mismatched)
418 : AccessIndexed(array, index, length, elt_type, state_before, mismatched)
419 , _value(value), _check_boolean(check_boolean)
420 {
421 #ifdef ASSERT
422 AssertValues assert_value;
423 values_do(&assert_value);
424 #endif
425 pin();
426 }
427
428
429 // Implementation of Invoke
430
431
432 Invoke::Invoke(Bytecodes::Code code, ValueType* result_type, Value recv, Values* args,
433 ciMethod* target, ValueStack* state_before)
434 : StateSplit(result_type, state_before)
435 , _code(code)
436 , _recv(recv)
437 , _args(args)
438 , _target(target)
439 {
440 set_flag(TargetIsLoadedFlag, target->is_loaded());
441 set_flag(TargetIsFinalFlag, target_is_loaded() && target->is_final_method());
442
443 assert(args != nullptr, "args must exist");
444 #ifdef ASSERT
445 AssertValues assert_value;
446 values_do(&assert_value);
447 #endif
448
449 // provide an initial guess of signature size.
450 _signature = new BasicTypeList(number_of_arguments() + (has_receiver() ? 1 : 0));
451 if (has_receiver()) {
452 _signature->append(as_BasicType(receiver()->type()));
453 }
454 for (int i = 0; i < number_of_arguments(); i++) {
455 Value v = argument_at(i);
456 ValueType* t = v->type();
457 BasicType bt = as_BasicType(t);
458 _signature->append(bt);
459 }
460 }
461
462
463 void Invoke::state_values_do(ValueVisitor* f) {
464 StateSplit::state_values_do(f);
465 if (state_before() != nullptr) state_before()->values_do(f);
466 if (state() != nullptr) state()->values_do(f);
467 }
468
469 ciType* Invoke::declared_type() const {
470 ciSignature* declared_signature = state()->scope()->method()->get_declared_signature_at_bci(state()->bci());
471 ciType *t = declared_signature->return_type();
472 assert(t->basic_type() != T_VOID, "need return value of void method?");
473 return t;
474 }
475
476 // Implementation of Constant
477 intx Constant::hash() const {
478 if (state_before() == nullptr) {
479 switch (type()->tag()) {
480 case intTag:
481 return HASH2(name(), type()->as_IntConstant()->value());
482 case addressTag:
483 return HASH2(name(), type()->as_AddressConstant()->value());
484 case longTag:
485 {
486 jlong temp = type()->as_LongConstant()->value();
487 return HASH3(name(), high(temp), low(temp));
488 }
489 case floatTag:
490 return HASH2(name(), jint_cast(type()->as_FloatConstant()->value()));
491 case doubleTag:
492 {
493 jlong temp = jlong_cast(type()->as_DoubleConstant()->value());
494 return HASH3(name(), high(temp), low(temp));
495 }
496 case objectTag:
497 assert(type()->as_ObjectType()->is_loaded(), "can't handle unloaded values");
498 return HASH2(name(), type()->as_ObjectType()->constant_value());
499 case metaDataTag:
500 assert(type()->as_MetadataType()->is_loaded(), "can't handle unloaded values");
501 return HASH2(name(), type()->as_MetadataType()->constant_value());
502 default:
503 ShouldNotReachHere();
504 }
505 }
506 return 0;
507 }
508
509 bool Constant::is_equal(Value v) const {
510 if (v->as_Constant() == nullptr) return false;
511
512 switch (type()->tag()) {
513 case intTag:
514 {
515 IntConstant* t1 = type()->as_IntConstant();
516 IntConstant* t2 = v->type()->as_IntConstant();
517 return (t1 != nullptr && t2 != nullptr &&
518 t1->value() == t2->value());
519 }
520 case longTag:
521 {
522 LongConstant* t1 = type()->as_LongConstant();
523 LongConstant* t2 = v->type()->as_LongConstant();
524 return (t1 != nullptr && t2 != nullptr &&
525 t1->value() == t2->value());
526 }
527 case floatTag:
528 {
529 FloatConstant* t1 = type()->as_FloatConstant();
530 FloatConstant* t2 = v->type()->as_FloatConstant();
531 return (t1 != nullptr && t2 != nullptr &&
532 jint_cast(t1->value()) == jint_cast(t2->value()));
533 }
534 case doubleTag:
535 {
536 DoubleConstant* t1 = type()->as_DoubleConstant();
537 DoubleConstant* t2 = v->type()->as_DoubleConstant();
538 return (t1 != nullptr && t2 != nullptr &&
539 jlong_cast(t1->value()) == jlong_cast(t2->value()));
540 }
541 case objectTag:
542 {
543 ObjectType* t1 = type()->as_ObjectType();
544 ObjectType* t2 = v->type()->as_ObjectType();
545 return (t1 != nullptr && t2 != nullptr &&
546 t1->is_loaded() && t2->is_loaded() &&
547 t1->constant_value() == t2->constant_value());
548 }
549 case metaDataTag:
550 {
551 MetadataType* t1 = type()->as_MetadataType();
552 MetadataType* t2 = v->type()->as_MetadataType();
553 return (t1 != nullptr && t2 != nullptr &&
554 t1->is_loaded() && t2->is_loaded() &&
555 t1->constant_value() == t2->constant_value());
556 }
557 default:
558 return false;
559 }
560 }
561
562 Constant::CompareResult Constant::compare(Instruction::Condition cond, Value right) const {
563 Constant* rc = right->as_Constant();
564 // other is not a constant
565 if (rc == nullptr) return not_comparable;
566
567 ValueType* lt = type();
568 ValueType* rt = rc->type();
569 // different types
570 if (lt->base() != rt->base()) return not_comparable;
571 switch (lt->tag()) {
572 case intTag: {
573 int x = lt->as_IntConstant()->value();
574 int y = rt->as_IntConstant()->value();
575 switch (cond) {
576 case If::eql: return x == y ? cond_true : cond_false;
577 case If::neq: return x != y ? cond_true : cond_false;
578 case If::lss: return x < y ? cond_true : cond_false;
579 case If::leq: return x <= y ? cond_true : cond_false;
580 case If::gtr: return x > y ? cond_true : cond_false;
581 case If::geq: return x >= y ? cond_true : cond_false;
582 default : break;
583 }
584 break;
585 }
586 case longTag: {
587 jlong x = lt->as_LongConstant()->value();
588 jlong y = rt->as_LongConstant()->value();
589 switch (cond) {
590 case If::eql: return x == y ? cond_true : cond_false;
591 case If::neq: return x != y ? cond_true : cond_false;
592 case If::lss: return x < y ? cond_true : cond_false;
593 case If::leq: return x <= y ? cond_true : cond_false;
594 case If::gtr: return x > y ? cond_true : cond_false;
595 case If::geq: return x >= y ? cond_true : cond_false;
596 default : break;
597 }
598 break;
599 }
600 case objectTag: {
601 ciObject* xvalue = lt->as_ObjectType()->constant_value();
602 ciObject* yvalue = rt->as_ObjectType()->constant_value();
603 assert(xvalue != nullptr && yvalue != nullptr, "not constants");
604 if (xvalue->is_loaded() && yvalue->is_loaded()) {
605 switch (cond) {
606 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
607 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
608 default : break;
609 }
610 }
611 break;
612 }
613 case metaDataTag: {
614 ciMetadata* xvalue = lt->as_MetadataType()->constant_value();
615 ciMetadata* yvalue = rt->as_MetadataType()->constant_value();
616 assert(xvalue != nullptr && yvalue != nullptr, "not constants");
617 if (xvalue->is_loaded() && yvalue->is_loaded()) {
618 switch (cond) {
619 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
620 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
621 default : break;
622 }
623 }
624 break;
625 }
626 default:
627 break;
628 }
629 return not_comparable;
630 }
631
632
633 // Implementation of BlockBegin
634
635 void BlockBegin::set_end(BlockEnd* new_end) { // Assumes that no predecessor of new_end still has it as its successor
636 assert(new_end != nullptr, "Should not reset block new_end to null");
637 if (new_end == _end) return;
638
639 // Remove this block as predecessor of its current successors
640 if (_end != nullptr) {
641 for (int i = 0; i < number_of_sux(); i++) {
642 sux_at(i)->remove_predecessor(this);
643 }
644 }
645
646 _end = new_end;
647
648 // Add this block as predecessor of its new successors
649 for (int i = 0; i < number_of_sux(); i++) {
650 sux_at(i)->add_predecessor(this);
651 }
652 }
653
654
655 void BlockBegin::disconnect_edge(BlockBegin* from, BlockBegin* to) {
656 // disconnect any edges between from and to
657 #ifndef PRODUCT
658 if (PrintIR && Verbose) {
659 tty->print_cr("Disconnected edge B%d -> B%d", from->block_id(), to->block_id());
660 }
661 #endif
662 for (int s = 0; s < from->number_of_sux();) {
663 BlockBegin* sux = from->sux_at(s);
664 if (sux == to) {
665 int index = sux->_predecessors.find(from);
666 if (index >= 0) {
667 sux->_predecessors.remove_at(index);
668 }
669 from->end()->remove_sux_at(s);
670 } else {
671 s++;
672 }
673 }
674 }
675
676
677 void BlockBegin::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
678 // modify predecessors before substituting successors
679 for (int i = 0; i < number_of_sux(); i++) {
680 if (sux_at(i) == old_sux) {
681 // remove old predecessor before adding new predecessor
682 // otherwise there is a dead predecessor in the list
683 new_sux->remove_predecessor(old_sux);
684 new_sux->add_predecessor(this);
685 }
686 }
687 old_sux->remove_predecessor(this);
688 end()->substitute_sux(old_sux, new_sux);
689 }
690
691
692
693 // In general it is not possible to calculate a value for the field "depth_first_number"
694 // of the inserted block, without recomputing the values of the other blocks
695 // in the CFG. Therefore the value of "depth_first_number" in BlockBegin becomes meaningless.
696 BlockBegin* BlockBegin::insert_block_between(BlockBegin* sux) {
697 assert(!sux->is_set(critical_edge_split_flag), "sanity check");
698
699 int bci = sux->bci();
700 // critical edge splitting may introduce a goto after a if and array
701 // bound check elimination may insert a predicate between the if and
702 // goto. The bci of the goto can't be the one of the if otherwise
703 // the state and bci are inconsistent and a deoptimization triggered
704 // by the predicate would lead to incorrect execution/a crash.
705 BlockBegin* new_sux = new BlockBegin(bci);
706
707 // mark this block (special treatment when block order is computed)
708 new_sux->set(critical_edge_split_flag);
709
710 // This goto is not a safepoint.
711 Goto* e = new Goto(sux, false);
712 new_sux->set_next(e, bci);
713 new_sux->set_end(e);
714 // setup states
715 ValueStack* s = end()->state();
716 new_sux->set_state(s->copy(s->kind(), bci));
717 e->set_state(s->copy(s->kind(), bci));
718 assert(new_sux->state()->locals_size() == s->locals_size(), "local size mismatch!");
719 assert(new_sux->state()->stack_size() == s->stack_size(), "stack size mismatch!");
720 assert(new_sux->state()->locks_size() == s->locks_size(), "locks size mismatch!");
721
722 // link predecessor to new block
723 end()->substitute_sux(sux, new_sux);
724
725 // The ordering needs to be the same, so remove the link that the
726 // set_end call above added and substitute the new_sux for this
727 // block.
728 sux->remove_predecessor(new_sux);
729
730 // the successor could be the target of a switch so it might have
731 // multiple copies of this predecessor, so substitute the new_sux
732 // for the first and delete the rest.
733 bool assigned = false;
734 BlockList& list = sux->_predecessors;
735 for (int i = 0; i < list.length(); i++) {
736 BlockBegin** b = list.adr_at(i);
737 if (*b == this) {
738 if (assigned) {
739 list.remove_at(i);
740 // reprocess this index
741 i--;
742 } else {
743 assigned = true;
744 *b = new_sux;
745 }
746 // link the new block back to it's predecessors.
747 new_sux->add_predecessor(this);
748 }
749 }
750 assert(assigned == true, "should have assigned at least once");
751 return new_sux;
752 }
753
754
755 void BlockBegin::add_predecessor(BlockBegin* pred) {
756 _predecessors.append(pred);
757 }
758
759
760 void BlockBegin::remove_predecessor(BlockBegin* pred) {
761 int idx;
762 while ((idx = _predecessors.find(pred)) >= 0) {
763 _predecessors.remove_at(idx);
764 }
765 }
766
767
768 void BlockBegin::add_exception_handler(BlockBegin* b) {
769 assert(b != nullptr && (b->is_set(exception_entry_flag)), "exception handler must exist");
770 // add only if not in the list already
771 if (!_exception_handlers.contains(b)) _exception_handlers.append(b);
772 }
773
774 int BlockBegin::add_exception_state(ValueStack* state) {
775 assert(is_set(exception_entry_flag), "only for xhandlers");
776 if (_exception_states == nullptr) {
777 _exception_states = new ValueStackStack(4);
778 }
779 _exception_states->append(state);
780 return _exception_states->length() - 1;
781 }
782
783
784 void BlockBegin::iterate_preorder(boolArray& mark, BlockClosure* closure) {
785 if (!mark.at(block_id())) {
786 mark.at_put(block_id(), true);
787 closure->block_do(this);
788 BlockEnd* e = end(); // must do this after block_do because block_do may change it!
789 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_preorder(mark, closure); }
790 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_preorder(mark, closure); }
791 }
792 }
793
794
795 void BlockBegin::iterate_postorder(boolArray& mark, BlockClosure* closure) {
796 if (!mark.at(block_id())) {
797 mark.at_put(block_id(), true);
798 BlockEnd* e = end();
799 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_postorder(mark, closure); }
800 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_postorder(mark, closure); }
801 closure->block_do(this);
802 }
803 }
804
805
806 void BlockBegin::iterate_preorder(BlockClosure* closure) {
807 int mark_len = number_of_blocks();
808 boolArray mark(mark_len, mark_len, false);
809 iterate_preorder(mark, closure);
810 }
811
812
813 void BlockBegin::iterate_postorder(BlockClosure* closure) {
814 int mark_len = number_of_blocks();
815 boolArray mark(mark_len, mark_len, false);
816 iterate_postorder(mark, closure);
817 }
818
819
820 void BlockBegin::block_values_do(ValueVisitor* f) {
821 for (Instruction* n = this; n != nullptr; n = n->next()) n->values_do(f);
822 }
823
824
825 #ifndef PRODUCT
826 #define TRACE_PHI(code) if (PrintPhiFunctions) { code; }
827 #else
828 #define TRACE_PHI(coce)
829 #endif
830
831
832 bool BlockBegin::try_merge(ValueStack* new_state, bool has_irreducible_loops) {
833 TRACE_PHI(tty->print_cr("********** try_merge for block B%d", block_id()));
834
835 // local variables used for state iteration
836 int index;
837 Value new_value, existing_value;
838
839 ValueStack* existing_state = state();
840 if (existing_state == nullptr) {
841 TRACE_PHI(tty->print_cr("first call of try_merge for this block"));
842
843 if (is_set(BlockBegin::was_visited_flag)) {
844 // this actually happens for complicated jsr/ret structures
845 return false; // BAILOUT in caller
846 }
847
848 // copy state because it is altered
849 new_state = new_state->copy(ValueStack::BlockBeginState, bci());
850
851 // Use method liveness to invalidate dead locals
852 MethodLivenessResult liveness = new_state->scope()->method()->liveness_at_bci(bci());
853 if (liveness.is_valid()) {
854 assert((int)liveness.size() == new_state->locals_size(), "error in use of liveness");
855
856 for_each_local_value(new_state, index, new_value) {
857 if (!liveness.at(index) || new_value->type()->is_illegal()) {
858 new_state->invalidate_local(index);
859 TRACE_PHI(tty->print_cr("invalidating dead local %d", index));
860 }
861 }
862 }
863
864 if (is_set(BlockBegin::parser_loop_header_flag)) {
865 TRACE_PHI(tty->print_cr("loop header block, initializing phi functions"));
866
867 for_each_stack_value(new_state, index, new_value) {
868 new_state->setup_phi_for_stack(this, index);
869 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));
870 }
871
872 BitMap& requires_phi_function = new_state->scope()->requires_phi_function();
873 for_each_local_value(new_state, index, new_value) {
874 bool requires_phi = requires_phi_function.at(index) || (new_value->type()->is_double_word() && requires_phi_function.at(index + 1));
875 if (requires_phi || !SelectivePhiFunctions || has_irreducible_loops) {
876 new_state->setup_phi_for_local(this, index);
877 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));
878 }
879 }
880 }
881
882 // initialize state of block
883 set_state(new_state);
884
885 } else if (existing_state->is_same(new_state)) {
886 TRACE_PHI(tty->print_cr("existing state found"));
887
888 assert(existing_state->scope() == new_state->scope(), "not matching");
889 assert(existing_state->locals_size() == new_state->locals_size(), "not matching");
890 assert(existing_state->stack_size() == new_state->stack_size(), "not matching");
891
892 if (is_set(BlockBegin::was_visited_flag)) {
893 TRACE_PHI(tty->print_cr("loop header block, phis must be present"));
894
895 if (!is_set(BlockBegin::parser_loop_header_flag)) {
896 // this actually happens for complicated jsr/ret structures
897 return false; // BAILOUT in caller
898 }
899
900 for_each_local_value(existing_state, index, existing_value) {
901 Value new_value = new_state->local_at(index);
902 if (new_value == nullptr || new_value->type()->tag() != existing_value->type()->tag()) {
903 Phi* existing_phi = existing_value->as_Phi();
904 if (existing_phi == nullptr) {
905 return false; // BAILOUT in caller
906 }
907 // Invalidate the phi function here. This case is very rare except for
908 // JVMTI capability "can_access_local_variables".
909 // In really rare cases we will bail out in LIRGenerator::move_to_phi.
910 existing_phi->make_illegal();
911 existing_state->invalidate_local(index);
912 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
913 }
914
915 if (existing_value != new_state->local_at(index) && existing_value->as_Phi() == nullptr) {
916 TRACE_PHI(tty->print_cr("required phi for local %d is missing, irreducible loop?", index));
917 return false; // BAILOUT in caller
918 }
919 }
920
921 #ifdef ASSERT
922 // check that all necessary phi functions are present
923 for_each_stack_value(existing_state, index, existing_value) {
924 assert(existing_value->as_Phi() != nullptr && existing_value->as_Phi()->block() == this, "phi function required");
925 }
926 for_each_local_value(existing_state, index, existing_value) {
927 assert(existing_value == new_state->local_at(index) || (existing_value->as_Phi() != nullptr && existing_value->as_Phi()->as_Phi()->block() == this), "phi function required");
928 }
929 #endif
930
931 } else {
932 TRACE_PHI(tty->print_cr("creating phi functions on demand"));
933
934 // create necessary phi functions for stack
935 for_each_stack_value(existing_state, index, existing_value) {
936 Value new_value = new_state->stack_at(index);
937 Phi* existing_phi = existing_value->as_Phi();
938
939 if (new_value != existing_value && (existing_phi == nullptr || existing_phi->block() != this)) {
940 existing_state->setup_phi_for_stack(this, index);
941 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));
942 }
943 }
944
945 // create necessary phi functions for locals
946 for_each_local_value(existing_state, index, existing_value) {
947 Value new_value = new_state->local_at(index);
948 Phi* existing_phi = existing_value->as_Phi();
949
950 if (new_value == nullptr || new_value->type()->tag() != existing_value->type()->tag()) {
951 existing_state->invalidate_local(index);
952 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
953 } else if (new_value != existing_value && (existing_phi == nullptr || existing_phi->block() != this)) {
954 existing_state->setup_phi_for_local(this, index);
955 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));
956 }
957 }
958 }
959
960 assert(existing_state->caller_state() == new_state->caller_state(), "caller states must be equal");
961
962 } else {
963 assert(false, "stack or locks not matching (invalid bytecodes)");
964 return false;
965 }
966
967 TRACE_PHI(tty->print_cr("********** try_merge for block B%d successful", block_id()));
968
969 return true;
970 }
971
972
973 #ifndef PRODUCT
974 void BlockBegin::print_block() {
975 InstructionPrinter ip;
976 print_block(ip, false);
977 }
978
979
980 void BlockBegin::print_block(InstructionPrinter& ip, bool live_only) {
981 ip.print_instr(this); tty->cr();
982 ip.print_stack(this->state()); tty->cr();
983 ip.print_inline_level(this);
984 ip.print_head();
985 for (Instruction* n = next(); n != nullptr; n = n->next()) {
986 if (!live_only || n->is_pinned() || n->use_count() > 0) {
987 ip.print_line(n);
988 }
989 }
990 tty->cr();
991 }
992 #endif // PRODUCT
993
994
995 // Implementation of BlockList
996
997 void BlockList::iterate_forward (BlockClosure* closure) {
998 const int l = length();
999 for (int i = 0; i < l; i++) closure->block_do(at(i));
1000 }
1001
1002
1003 void BlockList::iterate_backward(BlockClosure* closure) {
1004 for (int i = length() - 1; i >= 0; i--) closure->block_do(at(i));
1005 }
1006
1007
1008 void BlockList::values_do(ValueVisitor* f) {
1009 for (int i = length() - 1; i >= 0; i--) at(i)->block_values_do(f);
1010 }
1011
1012
1013 #ifndef PRODUCT
1014 void BlockList::print(bool cfg_only, bool live_only) {
1015 InstructionPrinter ip;
1016 for (int i = 0; i < length(); i++) {
1017 BlockBegin* block = at(i);
1018 if (cfg_only) {
1019 ip.print_instr(block); tty->cr();
1020 } else {
1021 block->print_block(ip, live_only);
1022 }
1023 }
1024 }
1025 #endif // PRODUCT
1026
1027
1028 // Implementation of BlockEnd
1029
1030 void BlockEnd::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
1031 substitute(*_sux, old_sux, new_sux);
1032 }
1033
1034 // Implementation of Phi
1035
1036 // Normal phi functions take their operands from the last instruction of the
1037 // predecessor. Special handling is needed for xhanlder entries because there
1038 // the state of arbitrary instructions are needed.
1039
1040 Value Phi::operand_at(int i) const {
1041 ValueStack* state;
1042 if (_block->is_set(BlockBegin::exception_entry_flag)) {
1043 state = _block->exception_state_at(i);
1044 } else {
1045 state = _block->pred_at(i)->end()->state();
1046 }
1047 assert(state != nullptr, "");
1048
1049 if (is_local()) {
1050 return state->local_at(local_index());
1051 } else {
1052 return state->stack_at(stack_index());
1053 }
1054 }
1055
1056
1057 int Phi::operand_count() const {
1058 if (_block->is_set(BlockBegin::exception_entry_flag)) {
1059 return _block->number_of_exception_states();
1060 } else {
1061 return _block->number_of_preds();
1062 }
1063 }
1064
1065 #ifdef ASSERT
1066 // Constructor of Assert
1067 Assert::Assert(Value x, Condition cond, bool unordered_is_true, Value y) : Instruction(illegalType)
1068 , _x(x)
1069 , _cond(cond)
1070 , _y(y)
1071 {
1072 set_flag(UnorderedIsTrueFlag, unordered_is_true);
1073 assert(x->type()->tag() == y->type()->tag(), "types must match");
1074 pin();
1075
1076 stringStream strStream;
1077 Compilation::current()->method()->print_name(&strStream);
1078
1079 stringStream strStream1;
1080 InstructionPrinter ip1(1, &strStream1);
1081 ip1.print_instr(x);
1082
1083 stringStream strStream2;
1084 InstructionPrinter ip2(1, &strStream2);
1085 ip2.print_instr(y);
1086
1087 stringStream ss;
1088 ss.print("Assertion %s %s %s in method %s", strStream1.freeze(), ip2.cond_name(cond), strStream2.freeze(), strStream.freeze());
1089
1090 _message = ss.as_string();
1091 }
1092 #endif
1093
1094 void RangeCheckPredicate::check_state() {
1095 assert(state()->kind() != ValueStack::EmptyExceptionState && state()->kind() != ValueStack::ExceptionState, "will deopt with empty state");
1096 }
1097
1098 void ProfileInvoke::state_values_do(ValueVisitor* f) {
1099 if (state() != nullptr) state()->values_do(f);
1100 }
1101