1 /*
2 * Copyright (c) 1999, 2026, 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() const {
137 if (UseArrayFlattening) {
138 ciType* type = declared_type();
139 if (type != nullptr) {
140 if (type->is_ref_array_klass()) {
141 return false;
142 } else if (type->is_flat_array_klass()) {
143 return true;
144 } else if (type->is_obj_array_klass()) {
145 // This is the unrefined array type
146 ciKlass* element_klass = type->as_obj_array_klass()->element_klass();
147 if (element_klass->can_be_inline_klass() && (!element_klass->is_inlinetype() || element_klass->as_inline_klass()->maybe_flat_in_array())) {
148 return true;
149 }
150 } else if (type->is_klass() && type->as_klass()->is_java_lang_Object()) {
151 // This can happen as a parameter to System.arraycopy()
152 return true;
153 }
154 } else {
155 // Type info gets lost during Phi merging (Phi, IfOp, etc), but we might be storing into a
156 // flat array, so we should do a runtime check.
157 return true;
158 }
159 }
160 return false;
161 }
162
163 bool Instruction::maybe_null_free_array() const {
164 ciType* type = declared_type();
165 if (type != nullptr) {
166 if (type->is_loaded() && type->is_array_klass() && type->as_array_klass()->is_refined()) {
167 return type->as_array_klass()->is_elem_null_free();
168 } else if (type->is_obj_array_klass()) {
169 // Due to array covariance, the runtime type might be a null-free array.
170 if (type->as_obj_array_klass()->can_be_inline_array_klass()) {
171 return true;
172 }
173 }
174 } else {
175 // Type info gets lost during Phi merging (Phi, IfOp, etc), but we might be storing into a
176 // null-free array, so we should do a runtime check.
177 return true;
178 }
179 return false;
180 }
181
182 #ifndef PRODUCT
183 void Instruction::check_state(ValueStack* state) {
184 if (state != nullptr) {
185 state->verify();
186 }
187 }
188
189
190 void Instruction::print() {
191 InstructionPrinter ip;
192 print(ip);
193 }
194
195
196 void Instruction::print_line() {
197 InstructionPrinter ip;
198 ip.print_line(this);
199 }
200
201
202 void Instruction::print(InstructionPrinter& ip) {
203 ip.print_head();
204 ip.print_line(this);
205 tty->cr();
206 }
207 #endif // PRODUCT
208
209
210 // perform constant and interval tests on index value
211 bool AccessIndexed::compute_needs_range_check() {
212 if (length()) {
213 Constant* clength = length()->as_Constant();
214 Constant* cindex = index()->as_Constant();
215 if (clength && cindex) {
216 IntConstant* l = clength->type()->as_IntConstant();
217 IntConstant* i = cindex->type()->as_IntConstant();
218 if (l && i && i->value() < l->value() && i->value() >= 0) {
219 return false;
220 }
221 }
222 }
223
224 if (!this->check_flag(NeedsRangeCheckFlag)) {
225 return false;
226 }
227
228 return true;
229 }
230
231
232 ciType* Constant::exact_type() const {
233 if (type()->is_object() && type()->as_ObjectType()->is_loaded()) {
234 return type()->as_ObjectType()->exact_type();
235 }
236 return nullptr;
237 }
238
239 ciType* LoadIndexed::exact_type() const {
240 ciType* array_type = array()->exact_type();
241 // A delayed load produces a field within the array element. Let
242 // Instruction::exact_type() below derive its type from declared_type().
243 if (delayed() == nullptr && array_type != nullptr) {
244 assert(array_type->is_array_klass(), "what else?");
245 ciArrayKlass* ak = (ciArrayKlass*)array_type;
246
247 if (ak->element_type()->is_instance_klass()) {
248 ciInstanceKlass* ik = (ciInstanceKlass*)ak->element_type();
249 if (ik->is_loaded() && ik->is_final()) {
250 return ik;
251 }
252 }
253 }
254 return Instruction::exact_type();
255 }
256
257 ciType* LoadIndexed::declared_type() const {
258 if (delayed() != nullptr) {
259 // The LoadIndexed is fused with one or more following getfield bytecodes
260 // and produces the final field value instead of the array element.
261 return delayed()->field()->type();
262 }
263 ciType* array_type = array()->declared_type();
264 if (array_type == nullptr || !array_type->is_loaded()) {
265 return nullptr;
266 }
267 assert(array_type->is_array_klass(), "what else?");
268 ciArrayKlass* ak = (ciArrayKlass*)array_type;
269 return ak->element_type();
270 }
271
272 bool StoreIndexed::is_exact_flat_array_store() const {
273 if (array()->is_loaded_flat_array() && value()->as_Constant() == nullptr && value()->declared_type() != nullptr) {
274 ciKlass* element_klass = array()->declared_type()->as_flat_array_klass()->element_klass();
275 ciKlass* actual_klass = value()->declared_type()->as_klass();
276
277 // Inlining can expose more specific types than the callee's signature. In
278 // this example, element_klass is MyValue1 and actual_klass is MyValue2, so
279 // the array store check must be kept:
280 // void test45_inline(Object[] oa, Object o, int index) { oa[index] = o; }
281 // void test45(MyValue1[] va, int index, MyValue2 v) { test45_inline(va, v, index); }
282 if (element_klass == actual_klass) {
283 return true;
284 }
285 }
286 return false;
287 }
288
289 ciType* LoadField::declared_type() const {
290 return field()->type();
291 }
292
293
294 ciType* NewTypeArray::exact_type() const {
295 return ciTypeArrayKlass::make(elt_type());
296 }
297
298 ciType* NewObjectArray::exact_type() const {
299 // Resolve the default array properties used by anewarray to a concrete
300 // layout klass (reference or flat), which is the exact type of the allocation.
301 return ciObjArrayKlass::make(klass());
302 }
303
304 ciType* NewMultiArray::exact_type() const {
305 return _klass;
306 }
307
308 ciType* NewArray::declared_type() const {
309 return exact_type();
310 }
311
312 ciType* NewInstance::exact_type() const {
313 return klass();
314 }
315
316 ciType* NewInstance::declared_type() const {
317 return exact_type();
318 }
319
320 ciType* CheckCast::declared_type() const {
321 return klass();
322 }
323
324 // Implementation of ArithmeticOp
325
326 bool ArithmeticOp::is_commutative() const {
327 switch (op()) {
328 case Bytecodes::_iadd: // fall through
329 case Bytecodes::_ladd: // fall through
330 case Bytecodes::_fadd: // fall through
331 case Bytecodes::_dadd: // fall through
332 case Bytecodes::_imul: // fall through
333 case Bytecodes::_lmul: // fall through
334 case Bytecodes::_fmul: // fall through
335 case Bytecodes::_dmul: return true;
336 default : return false;
337 }
338 }
339
340
341 bool ArithmeticOp::can_trap() const {
342 switch (op()) {
343 case Bytecodes::_idiv: // fall through
344 case Bytecodes::_ldiv: // fall through
345 case Bytecodes::_irem: // fall through
346 case Bytecodes::_lrem: return true;
347 default : return false;
348 }
349 }
350
351
352 // Implementation of LogicOp
353
354 bool LogicOp::is_commutative() const {
355 #ifdef ASSERT
356 switch (op()) {
357 case Bytecodes::_iand: // fall through
358 case Bytecodes::_land: // fall through
359 case Bytecodes::_ior : // fall through
360 case Bytecodes::_lor : // fall through
361 case Bytecodes::_ixor: // fall through
362 case Bytecodes::_lxor: break;
363 default : ShouldNotReachHere(); break;
364 }
365 #endif
366 // all LogicOps are commutative
367 return true;
368 }
369
370
371 // Implementation of IfOp
372
373 bool IfOp::is_commutative() const {
374 return cond() == eql || cond() == neq;
375 }
376
377
378 // Implementation of StateSplit
379
380 void StateSplit::substitute(BlockList& list, BlockBegin* old_block, BlockBegin* new_block) {
381 NOT_PRODUCT(bool assigned = false;)
382 for (int i = 0; i < list.length(); i++) {
383 BlockBegin** b = list.adr_at(i);
384 if (*b == old_block) {
385 *b = new_block;
386 NOT_PRODUCT(assigned = true;)
387 }
388 }
389 assert(assigned == true, "should have assigned at least once");
390 }
391
392
393 IRScope* StateSplit::scope() const {
394 return _state->scope();
395 }
396
397
398 void StateSplit::state_values_do(ValueVisitor* f) {
399 Instruction::state_values_do(f);
400 if (state() != nullptr) state()->values_do(f);
401 }
402
403
404 void BlockBegin::state_values_do(ValueVisitor* f) {
405 StateSplit::state_values_do(f);
406
407 if (is_set(BlockBegin::exception_entry_flag)) {
408 for (int i = 0; i < number_of_exception_states(); i++) {
409 exception_state_at(i)->values_do(f);
410 }
411 }
412 }
413
414
415 // Implementation of Invoke
416
417
418 Invoke::Invoke(Bytecodes::Code code, ciType* return_type, Value recv, Values* args,
419 ciMethod* target, ValueStack* state_before)
420 : StateSplit(as_ValueType(return_type), state_before)
421 , _code(code)
422 , _recv(recv)
423 , _args(args)
424 , _target(target)
425 , _return_type(return_type)
426 {
427 set_flag(TargetIsLoadedFlag, target->is_loaded());
428 set_flag(TargetIsFinalFlag, target_is_loaded() && target->is_final_method());
429
430 assert(args != nullptr, "args must exist");
431 #ifdef ASSERT
432 AssertValues assert_value;
433 values_do(&assert_value);
434 #endif
435
436 // provide an initial guess of signature size.
437 _signature = new BasicTypeList(number_of_arguments() + (has_receiver() ? 1 : 0));
438 if (has_receiver()) {
439 _signature->append(as_BasicType(receiver()->type()));
440 }
441 for (int i = 0; i < number_of_arguments(); i++) {
442 ValueType* t = argument_at(i)->type();
443 BasicType bt = as_BasicType(t);
444 _signature->append(bt);
445 }
446 }
447
448
449 void Invoke::state_values_do(ValueVisitor* f) {
450 StateSplit::state_values_do(f);
451 if (state_before() != nullptr) state_before()->values_do(f);
452 if (state() != nullptr) state()->values_do(f);
453 }
454
455 ciType* Invoke::declared_type() const {
456 assert(_return_type->basic_type() != T_VOID, "need return value of void method?");
457 return _return_type;
458 }
459
460 // Implementation of Constant
461 intx Constant::hash() const {
462 if (state_before() == nullptr) {
463 switch (type()->tag()) {
464 case intTag:
465 return HASH2(name(), type()->as_IntConstant()->value());
466 case addressTag:
467 return HASH2(name(), type()->as_AddressConstant()->value());
468 case longTag:
469 {
470 jlong temp = type()->as_LongConstant()->value();
471 return HASH3(name(), high(temp), low(temp));
472 }
473 case floatTag:
474 return HASH2(name(), jint_cast(type()->as_FloatConstant()->value()));
475 case doubleTag:
476 {
477 jlong temp = jlong_cast(type()->as_DoubleConstant()->value());
478 return HASH3(name(), high(temp), low(temp));
479 }
480 case objectTag:
481 assert(type()->as_ObjectType()->is_loaded(), "can't handle unloaded values");
482 return HASH2(name(), type()->as_ObjectType()->constant_value());
483 case metaDataTag:
484 assert(type()->as_MetadataType()->is_loaded(), "can't handle unloaded values");
485 return HASH2(name(), type()->as_MetadataType()->constant_value());
486 default:
487 ShouldNotReachHere();
488 }
489 }
490 return 0;
491 }
492
493 bool Constant::is_equal(Value v) const {
494 if (v->as_Constant() == nullptr) return false;
495
496 switch (type()->tag()) {
497 case intTag:
498 {
499 IntConstant* t1 = type()->as_IntConstant();
500 IntConstant* t2 = v->type()->as_IntConstant();
501 return (t1 != nullptr && t2 != nullptr &&
502 t1->value() == t2->value());
503 }
504 case longTag:
505 {
506 LongConstant* t1 = type()->as_LongConstant();
507 LongConstant* t2 = v->type()->as_LongConstant();
508 return (t1 != nullptr && t2 != nullptr &&
509 t1->value() == t2->value());
510 }
511 case floatTag:
512 {
513 FloatConstant* t1 = type()->as_FloatConstant();
514 FloatConstant* t2 = v->type()->as_FloatConstant();
515 return (t1 != nullptr && t2 != nullptr &&
516 jint_cast(t1->value()) == jint_cast(t2->value()));
517 }
518 case doubleTag:
519 {
520 DoubleConstant* t1 = type()->as_DoubleConstant();
521 DoubleConstant* t2 = v->type()->as_DoubleConstant();
522 return (t1 != nullptr && t2 != nullptr &&
523 jlong_cast(t1->value()) == jlong_cast(t2->value()));
524 }
525 case objectTag:
526 {
527 ObjectType* t1 = type()->as_ObjectType();
528 ObjectType* t2 = v->type()->as_ObjectType();
529 return (t1 != nullptr && t2 != nullptr &&
530 t1->is_loaded() && t2->is_loaded() &&
531 t1->constant_value() == t2->constant_value());
532 }
533 case metaDataTag:
534 {
535 MetadataType* t1 = type()->as_MetadataType();
536 MetadataType* t2 = v->type()->as_MetadataType();
537 return (t1 != nullptr && t2 != nullptr &&
538 t1->is_loaded() && t2->is_loaded() &&
539 t1->constant_value() == t2->constant_value());
540 }
541 default:
542 return false;
543 }
544 }
545
546 Constant::CompareResult Constant::compare(Instruction::Condition cond, Value right) const {
547 Constant* rc = right->as_Constant();
548 // other is not a constant
549 if (rc == nullptr) return not_comparable;
550
551 ValueType* lt = type();
552 ValueType* rt = rc->type();
553 // different types
554 if (lt->base() != rt->base()) return not_comparable;
555 switch (lt->tag()) {
556 case intTag: {
557 int x = lt->as_IntConstant()->value();
558 int y = rt->as_IntConstant()->value();
559 switch (cond) {
560 case If::eql: return x == y ? cond_true : cond_false;
561 case If::neq: return x != y ? cond_true : cond_false;
562 case If::lss: return x < y ? cond_true : cond_false;
563 case If::leq: return x <= y ? cond_true : cond_false;
564 case If::gtr: return x > y ? cond_true : cond_false;
565 case If::geq: return x >= y ? cond_true : cond_false;
566 default : break;
567 }
568 break;
569 }
570 case longTag: {
571 jlong x = lt->as_LongConstant()->value();
572 jlong y = rt->as_LongConstant()->value();
573 switch (cond) {
574 case If::eql: return x == y ? cond_true : cond_false;
575 case If::neq: return x != y ? cond_true : cond_false;
576 case If::lss: return x < y ? cond_true : cond_false;
577 case If::leq: return x <= y ? cond_true : cond_false;
578 case If::gtr: return x > y ? cond_true : cond_false;
579 case If::geq: return x >= y ? cond_true : cond_false;
580 default : break;
581 }
582 break;
583 }
584 case objectTag: {
585 ciObject* xvalue = lt->as_ObjectType()->constant_value();
586 ciObject* yvalue = rt->as_ObjectType()->constant_value();
587 assert(xvalue != nullptr && yvalue != nullptr, "not constants");
588 if (xvalue->is_loaded() && yvalue->is_loaded()) {
589 switch (cond) {
590 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
591 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
592 default : break;
593 }
594 }
595 break;
596 }
597 case metaDataTag: {
598 ciMetadata* xvalue = lt->as_MetadataType()->constant_value();
599 ciMetadata* yvalue = rt->as_MetadataType()->constant_value();
600 assert(xvalue != nullptr && yvalue != nullptr, "not constants");
601 if (xvalue->is_loaded() && yvalue->is_loaded()) {
602 switch (cond) {
603 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
604 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
605 default : break;
606 }
607 }
608 break;
609 }
610 default:
611 break;
612 }
613 return not_comparable;
614 }
615
616
617 // Implementation of BlockBegin
618
619 void BlockBegin::set_end(BlockEnd* new_end) { // Assumes that no predecessor of new_end still has it as its successor
620 assert(new_end != nullptr, "Should not reset block new_end to null");
621 if (new_end == _end) return;
622
623 // Remove this block as predecessor of its current successors
624 if (_end != nullptr) {
625 for (int i = 0; i < number_of_sux(); i++) {
626 sux_at(i)->remove_predecessor(this);
627 }
628 }
629
630 _end = new_end;
631
632 // Add this block as predecessor of its new successors
633 for (int i = 0; i < number_of_sux(); i++) {
634 sux_at(i)->add_predecessor(this);
635 }
636 }
637
638
639 void BlockBegin::disconnect_edge(BlockBegin* from, BlockBegin* to) {
640 // disconnect any edges between from and to
641 #ifndef PRODUCT
642 if (PrintIR && Verbose) {
643 tty->print_cr("Disconnected edge B%d -> B%d", from->block_id(), to->block_id());
644 }
645 #endif
646 for (int s = 0; s < from->number_of_sux();) {
647 BlockBegin* sux = from->sux_at(s);
648 if (sux == to) {
649 int index = sux->_predecessors.find(from);
650 if (index >= 0) {
651 sux->_predecessors.remove_at(index);
652 }
653 from->end()->remove_sux_at(s);
654 } else {
655 s++;
656 }
657 }
658 }
659
660
661 void BlockBegin::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
662 // modify predecessors before substituting successors
663 for (int i = 0; i < number_of_sux(); i++) {
664 if (sux_at(i) == old_sux) {
665 // remove old predecessor before adding new predecessor
666 // otherwise there is a dead predecessor in the list
667 new_sux->remove_predecessor(old_sux);
668 new_sux->add_predecessor(this);
669 }
670 }
671 old_sux->remove_predecessor(this);
672 end()->substitute_sux(old_sux, new_sux);
673 }
674
675
676
677 // In general it is not possible to calculate a value for the field "depth_first_number"
678 // of the inserted block, without recomputing the values of the other blocks
679 // in the CFG. Therefore the value of "depth_first_number" in BlockBegin becomes meaningless.
680 BlockBegin* BlockBegin::insert_block_between(BlockBegin* sux) {
681 assert(!sux->is_set(critical_edge_split_flag), "sanity check");
682
683 int bci = sux->bci();
684 // critical edge splitting may introduce a goto after a if and array
685 // bound check elimination may insert a predicate between the if and
686 // goto. The bci of the goto can't be the one of the if otherwise
687 // the state and bci are inconsistent and a deoptimization triggered
688 // by the predicate would lead to incorrect execution/a crash.
689 BlockBegin* new_sux = new BlockBegin(bci);
690
691 // mark this block (special treatment when block order is computed)
692 new_sux->set(critical_edge_split_flag);
693
694 // This goto is not a safepoint.
695 Goto* e = new Goto(sux, false);
696 new_sux->set_next(e, bci);
697 new_sux->set_end(e);
698 // setup states
699 ValueStack* s = end()->state();
700 new_sux->set_state(s->copy(s->kind(), bci));
701 e->set_state(s->copy(s->kind(), bci));
702 assert(new_sux->state()->locals_size() == s->locals_size(), "local size mismatch!");
703 assert(new_sux->state()->stack_size() == s->stack_size(), "stack size mismatch!");
704 assert(new_sux->state()->locks_size() == s->locks_size(), "locks size mismatch!");
705
706 // link predecessor to new block
707 end()->substitute_sux(sux, new_sux);
708
709 // The ordering needs to be the same, so remove the link that the
710 // set_end call above added and substitute the new_sux for this
711 // block.
712 sux->remove_predecessor(new_sux);
713
714 // the successor could be the target of a switch so it might have
715 // multiple copies of this predecessor, so substitute the new_sux
716 // for the first and delete the rest.
717 bool assigned = false;
718 BlockList& list = sux->_predecessors;
719 for (int i = 0; i < list.length(); i++) {
720 BlockBegin** b = list.adr_at(i);
721 if (*b == this) {
722 if (assigned) {
723 list.remove_at(i);
724 // reprocess this index
725 i--;
726 } else {
727 assigned = true;
728 *b = new_sux;
729 }
730 // link the new block back to it's predecessors.
731 new_sux->add_predecessor(this);
732 }
733 }
734 assert(assigned == true, "should have assigned at least once");
735 return new_sux;
736 }
737
738
739 void BlockBegin::add_predecessor(BlockBegin* pred) {
740 _predecessors.append(pred);
741 }
742
743
744 void BlockBegin::remove_predecessor(BlockBegin* pred) {
745 int idx;
746 while ((idx = _predecessors.find(pred)) >= 0) {
747 _predecessors.remove_at(idx);
748 }
749 }
750
751
752 void BlockBegin::add_exception_handler(BlockBegin* b) {
753 assert(b != nullptr && (b->is_set(exception_entry_flag)), "exception handler must exist");
754 // add only if not in the list already
755 if (!_exception_handlers.contains(b)) _exception_handlers.append(b);
756 }
757
758 int BlockBegin::add_exception_state(ValueStack* state) {
759 assert(is_set(exception_entry_flag), "only for xhandlers");
760 if (_exception_states == nullptr) {
761 _exception_states = new ValueStackStack(4);
762 }
763 _exception_states->append(state);
764 return _exception_states->length() - 1;
765 }
766
767
768 void BlockBegin::iterate_preorder(boolArray& mark, BlockClosure* closure) {
769 if (!mark.at(block_id())) {
770 mark.at_put(block_id(), true);
771 closure->block_do(this);
772 BlockEnd* e = end(); // must do this after block_do because block_do may change it!
773 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_preorder(mark, closure); }
774 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_preorder(mark, closure); }
775 }
776 }
777
778
779 void BlockBegin::iterate_postorder(boolArray& mark, BlockClosure* closure) {
780 if (!mark.at(block_id())) {
781 mark.at_put(block_id(), true);
782 BlockEnd* e = end();
783 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_postorder(mark, closure); }
784 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_postorder(mark, closure); }
785 closure->block_do(this);
786 }
787 }
788
789
790 void BlockBegin::iterate_preorder(BlockClosure* closure) {
791 int mark_len = number_of_blocks();
792 boolArray mark(mark_len, mark_len, false);
793 iterate_preorder(mark, closure);
794 }
795
796
797 void BlockBegin::iterate_postorder(BlockClosure* closure) {
798 int mark_len = number_of_blocks();
799 boolArray mark(mark_len, mark_len, false);
800 iterate_postorder(mark, closure);
801 }
802
803
804 void BlockBegin::block_values_do(ValueVisitor* f) {
805 for (Instruction* n = this; n != nullptr; n = n->next()) n->values_do(f);
806 }
807
808
809 #ifndef PRODUCT
810 #define TRACE_PHI(code) if (PrintPhiFunctions) { code; }
811 #else
812 #define TRACE_PHI(coce)
813 #endif
814
815
816 bool BlockBegin::try_merge(ValueStack* new_state, bool has_irreducible_loops) {
817 TRACE_PHI(tty->print_cr("********** try_merge for block B%d", block_id()));
818
819 // local variables used for state iteration
820 int index;
821 Value new_value, existing_value;
822
823 ValueStack* existing_state = state();
824 if (existing_state == nullptr) {
825 TRACE_PHI(tty->print_cr("first call of try_merge for this block"));
826
827 if (is_set(BlockBegin::was_visited_flag)) {
828 // this actually happens for complicated jsr/ret structures
829 return false; // BAILOUT in caller
830 }
831
832 // copy state because it is altered
833 new_state = new_state->copy(ValueStack::BlockBeginState, bci());
834
835 // Use method liveness to invalidate dead locals
836 MethodLivenessResult liveness = new_state->scope()->method()->liveness_at_bci(bci());
837 if (liveness.is_valid()) {
838 assert((int)liveness.size() == new_state->locals_size(), "error in use of liveness");
839
840 for_each_local_value(new_state, index, new_value) {
841 if (!liveness.at(index) || new_value->type()->is_illegal()) {
842 new_state->invalidate_local(index);
843 TRACE_PHI(tty->print_cr("invalidating dead local %d", index));
844 }
845 }
846 }
847
848 if (is_set(BlockBegin::parser_loop_header_flag)) {
849 TRACE_PHI(tty->print_cr("loop header block, initializing phi functions"));
850
851 for_each_stack_value(new_state, index, new_value) {
852 new_state->setup_phi_for_stack(this, index);
853 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));
854 }
855
856 BitMap& requires_phi_function = new_state->scope()->requires_phi_function();
857 for_each_local_value(new_state, index, new_value) {
858 bool requires_phi = requires_phi_function.at(index) || (new_value->type()->is_double_word() && requires_phi_function.at(index + 1));
859 if (requires_phi || !SelectivePhiFunctions || has_irreducible_loops) {
860 new_state->setup_phi_for_local(this, index);
861 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));
862 }
863 }
864 }
865
866 // initialize state of block
867 set_state(new_state);
868
869 } else if (existing_state->is_same(new_state)) {
870 TRACE_PHI(tty->print_cr("existing state found"));
871
872 assert(existing_state->scope() == new_state->scope(), "not matching");
873 assert(existing_state->locals_size() == new_state->locals_size(), "not matching");
874 assert(existing_state->stack_size() == new_state->stack_size(), "not matching");
875
876 if (is_set(BlockBegin::was_visited_flag)) {
877 TRACE_PHI(tty->print_cr("loop header block, phis must be present"));
878
879 if (!is_set(BlockBegin::parser_loop_header_flag)) {
880 // this actually happens for complicated jsr/ret structures
881 return false; // BAILOUT in caller
882 }
883
884 for_each_local_value(existing_state, index, existing_value) {
885 Value new_value = new_state->local_at(index);
886 if (new_value == nullptr || new_value->type()->tag() != existing_value->type()->tag()) {
887 Phi* existing_phi = existing_value->as_Phi();
888 if (existing_phi == nullptr) {
889 return false; // BAILOUT in caller
890 }
891 // Invalidate the phi function here. This case is very rare except for
892 // JVMTI capability "can_access_local_variables".
893 // In really rare cases we will bail out in LIRGenerator::move_to_phi.
894 existing_phi->make_illegal();
895 existing_state->invalidate_local(index);
896 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
897 }
898
899 if (existing_value != new_state->local_at(index) && existing_value->as_Phi() == nullptr) {
900 TRACE_PHI(tty->print_cr("required phi for local %d is missing, irreducible loop?", index));
901 return false; // BAILOUT in caller
902 }
903 }
904
905 #ifdef ASSERT
906 // check that all necessary phi functions are present
907 for_each_stack_value(existing_state, index, existing_value) {
908 assert(existing_value->as_Phi() != nullptr && existing_value->as_Phi()->block() == this, "phi function required");
909 }
910 for_each_local_value(existing_state, index, existing_value) {
911 assert(existing_value == new_state->local_at(index) || (existing_value->as_Phi() != nullptr && existing_value->as_Phi()->as_Phi()->block() == this), "phi function required");
912 }
913 #endif
914
915 } else {
916 TRACE_PHI(tty->print_cr("creating phi functions on demand"));
917
918 // create necessary phi functions for stack
919 for_each_stack_value(existing_state, index, existing_value) {
920 Value new_value = new_state->stack_at(index);
921 Phi* existing_phi = existing_value->as_Phi();
922
923 if (new_value != existing_value && (existing_phi == nullptr || existing_phi->block() != this)) {
924 existing_state->setup_phi_for_stack(this, index);
925 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));
926 }
927 }
928
929 // create necessary phi functions for locals
930 for_each_local_value(existing_state, index, existing_value) {
931 Value new_value = new_state->local_at(index);
932 Phi* existing_phi = existing_value->as_Phi();
933
934 if (new_value == nullptr || new_value->type()->tag() != existing_value->type()->tag()) {
935 existing_state->invalidate_local(index);
936 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
937 } else if (new_value != existing_value && (existing_phi == nullptr || existing_phi->block() != this)) {
938 existing_state->setup_phi_for_local(this, index);
939 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));
940 }
941 }
942 }
943
944 assert(existing_state->caller_state() == new_state->caller_state(), "caller states must be equal");
945
946 } else {
947 assert(false, "stack or locks not matching (invalid bytecodes)");
948 return false;
949 }
950
951 TRACE_PHI(tty->print_cr("********** try_merge for block B%d successful", block_id()));
952
953 return true;
954 }
955
956
957 #ifndef PRODUCT
958 void BlockBegin::print_block() {
959 InstructionPrinter ip;
960 print_block(ip, false);
961 }
962
963
964 void BlockBegin::print_block(InstructionPrinter& ip, bool live_only) {
965 ip.print_instr(this); tty->cr();
966 ip.print_stack(this->state()); tty->cr();
967 ip.print_inline_level(this);
968 ip.print_head();
969 for (Instruction* n = next(); n != nullptr; n = n->next()) {
970 if (!live_only || n->is_pinned() || n->use_count() > 0) {
971 ip.print_line(n);
972 }
973 }
974 tty->cr();
975 }
976 #endif // PRODUCT
977
978
979 // Implementation of BlockList
980
981 void BlockList::iterate_forward (BlockClosure* closure) {
982 const int l = length();
983 for (int i = 0; i < l; i++) closure->block_do(at(i));
984 }
985
986
987 void BlockList::iterate_backward(BlockClosure* closure) {
988 for (int i = length() - 1; i >= 0; i--) closure->block_do(at(i));
989 }
990
991
992 void BlockList::values_do(ValueVisitor* f) {
993 for (int i = length() - 1; i >= 0; i--) at(i)->block_values_do(f);
994 }
995
996
997 #ifndef PRODUCT
998 void BlockList::print(bool cfg_only, bool live_only) {
999 InstructionPrinter ip;
1000 for (int i = 0; i < length(); i++) {
1001 BlockBegin* block = at(i);
1002 if (cfg_only) {
1003 ip.print_instr(block); tty->cr();
1004 } else {
1005 block->print_block(ip, live_only);
1006 }
1007 }
1008 }
1009 #endif // PRODUCT
1010
1011
1012 // Implementation of BlockEnd
1013
1014 void BlockEnd::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
1015 substitute(*_sux, old_sux, new_sux);
1016 }
1017
1018 // Implementation of Phi
1019
1020 // Normal phi functions take their operands from the last instruction of the
1021 // predecessor. Special handling is needed for xhanlder entries because there
1022 // the state of arbitrary instructions are needed.
1023
1024 Value Phi::operand_at(int i) const {
1025 ValueStack* state;
1026 if (_block->is_set(BlockBegin::exception_entry_flag)) {
1027 state = _block->exception_state_at(i);
1028 } else {
1029 state = _block->pred_at(i)->end()->state();
1030 }
1031 assert(state != nullptr, "");
1032
1033 if (is_local()) {
1034 return state->local_at(local_index());
1035 } else {
1036 return state->stack_at(stack_index());
1037 }
1038 }
1039
1040
1041 int Phi::operand_count() const {
1042 if (_block->is_set(BlockBegin::exception_entry_flag)) {
1043 return _block->number_of_exception_states();
1044 } else {
1045 return _block->number_of_preds();
1046 }
1047 }
1048
1049 #ifdef ASSERT
1050 // Constructor of Assert
1051 Assert::Assert(Value x, Condition cond, bool unordered_is_true, Value y) : Instruction(illegalType)
1052 , _x(x)
1053 , _cond(cond)
1054 , _y(y)
1055 {
1056 set_flag(UnorderedIsTrueFlag, unordered_is_true);
1057 assert(x->type()->tag() == y->type()->tag(), "types must match");
1058 pin();
1059
1060 stringStream strStream;
1061 Compilation::current()->method()->print_name(&strStream);
1062
1063 stringStream strStream1;
1064 InstructionPrinter ip1(1, &strStream1);
1065 ip1.print_instr(x);
1066
1067 stringStream strStream2;
1068 InstructionPrinter ip2(1, &strStream2);
1069 ip2.print_instr(y);
1070
1071 stringStream ss;
1072 ss.print("Assertion %s %s %s in method %s", strStream1.freeze(), ip2.cond_name(cond), strStream2.freeze(), strStream.freeze());
1073
1074 _message = ss.as_string();
1075 }
1076 #endif
1077
1078 void RangeCheckPredicate::check_state() {
1079 assert(state()->kind() != ValueStack::EmptyExceptionState && state()->kind() != ValueStack::ExceptionState, "will deopt with empty state");
1080 }
1081
1082 void ProfileInvoke::state_values_do(ValueVisitor* f) {
1083 if (state() != nullptr) state()->values_do(f);
1084 }