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/ciFlatArrayKlass.hpp"
31 #include "ci/ciInlineKlass.hpp"
32 #include "ci/ciObjArrayKlass.hpp"
33 #include "ci/ciTypeArrayKlass.hpp"
34 #include "utilities/bitMap.inline.hpp"
35
36
37 // Implementation of Instruction
38
39
40 int Instruction::dominator_depth() {
41 int result = -1;
42 if (block()) {
43 result = block()->dominator_depth();
44 }
45 assert(result != -1 || this->as_Local(), "Only locals have dominator depth -1");
46 return result;
47 }
48
49 Instruction::Condition Instruction::mirror(Condition cond) {
50 switch (cond) {
51 case eql: return eql;
52 case neq: return neq;
53 case lss: return gtr;
54 case leq: return geq;
55 case gtr: return lss;
56 case geq: return leq;
57 case aeq: return beq;
58 case beq: return aeq;
59 }
60 ShouldNotReachHere();
61 return eql;
62 }
63
64
65 Instruction::Condition Instruction::negate(Condition cond) {
66 switch (cond) {
67 case eql: return neq;
68 case neq: return eql;
69 case lss: return geq;
70 case leq: return gtr;
71 case gtr: return leq;
72 case geq: return lss;
73 case aeq: assert(false, "Above equal cannot be negated");
74 case beq: assert(false, "Below equal cannot be negated");
75 }
76 ShouldNotReachHere();
77 return eql;
78 }
79
80 void Instruction::update_exception_state(ValueStack* state) {
81 if (state != nullptr && (state->kind() == ValueStack::EmptyExceptionState || state->kind() == ValueStack::ExceptionState)) {
82 assert(state->kind() == ValueStack::EmptyExceptionState || Compilation::current()->env()->should_retain_local_variables(), "unexpected state kind");
83 _exception_state = state;
84 } else {
85 _exception_state = nullptr;
86 }
87 }
88
89 // Prev without need to have BlockBegin
90 Instruction* Instruction::prev() {
91 Instruction* p = nullptr;
92 Instruction* q = block();
93 while (q != this) {
94 assert(q != nullptr, "this is not in the block's instruction list");
95 p = q; q = q->next();
96 }
97 return p;
98 }
99
100
101 void Instruction::state_values_do(ValueVisitor* f) {
102 if (state_before() != nullptr) {
103 state_before()->values_do(f);
104 }
105 if (exception_state() != nullptr) {
106 exception_state()->values_do(f);
107 }
108 }
109
110 ciType* Instruction::exact_type() const {
111 ciType* t = declared_type();
112 if (t != nullptr && t->is_klass()) {
113 return t->as_klass()->exact_klass();
114 }
115 return nullptr;
116 }
117
118 ciKlass* Instruction::as_loaded_klass_or_null() const {
119 ciType* type = declared_type();
120 if (type != nullptr && type->is_klass()) {
121 ciKlass* klass = type->as_klass();
122 if (klass->is_loaded()) {
123 return klass;
124 }
125 }
126 return nullptr;
127 }
128
129 bool Instruction::is_loaded_flat_array() const {
130 if (UseFlatArray) {
131 ciType* type = declared_type();
132 return type != nullptr && type->is_flat_array_klass();
133 }
134 return false;
135 }
136
137 bool Instruction::maybe_flat_array() {
138 if (UseFlatArray) {
139 ciType* type = declared_type();
140 if (type != nullptr) {
141 if (type->is_obj_array_klass()) {
142 // Due to array covariance, the runtime type might be a flat array.
143 ciKlass* element_klass = type->as_obj_array_klass()->element_klass();
144 if (element_klass->can_be_inline_klass() && (!element_klass->is_inlinetype() || element_klass->as_inline_klass()->flat_in_array())) {
145 return true;
146 }
147 } else if (type->is_flat_array_klass()) {
148 return true;
149 } else if (type->is_klass() && type->as_klass()->is_java_lang_Object()) {
150 // This can happen as a parameter to System.arraycopy()
151 return true;
152 }
153 } else {
154 // Type info gets lost during Phi merging (Phi, IfOp, etc), but we might be storing into a
155 // flat array, so we should do a runtime check.
156 return true;
157 }
158 }
159 return false;
160 }
161
162 bool Instruction::maybe_null_free_array() {
163 ciType* type = declared_type();
164 if (type != nullptr) {
165 if (type->is_obj_array_klass()) {
166 // Due to array covariance, the runtime type might be a null-free array.
167 if (type->as_obj_array_klass()->can_be_inline_array_klass()) {
168 return true;
169 }
170 }
171 } else {
172 // Type info gets lost during Phi merging (Phi, IfOp, etc), but we might be storing into a
173 // null-free array, so we should do a runtime check.
174 return true;
175 }
176 return false;
177 }
178
179 #ifndef PRODUCT
180 void Instruction::check_state(ValueStack* state) {
181 if (state != nullptr) {
182 state->verify();
183 }
184 }
185
186
187 void Instruction::print() {
188 InstructionPrinter ip;
189 print(ip);
190 }
191
192
193 void Instruction::print_line() {
194 InstructionPrinter ip;
195 ip.print_line(this);
196 }
197
198
199 void Instruction::print(InstructionPrinter& ip) {
200 ip.print_head();
201 ip.print_line(this);
202 tty->cr();
203 }
204 #endif // PRODUCT
205
206
207 // perform constant and interval tests on index value
208 bool AccessIndexed::compute_needs_range_check() {
209 if (length()) {
210 Constant* clength = length()->as_Constant();
211 Constant* cindex = index()->as_Constant();
212 if (clength && cindex) {
213 IntConstant* l = clength->type()->as_IntConstant();
214 IntConstant* i = cindex->type()->as_IntConstant();
215 if (l && i && i->value() < l->value() && i->value() >= 0) {
216 return false;
217 }
218 }
219 }
220
221 if (!this->check_flag(NeedsRangeCheckFlag)) {
222 return false;
223 }
224
225 return true;
226 }
227
228
229 ciType* Constant::exact_type() const {
230 if (type()->is_object() && type()->as_ObjectType()->is_loaded()) {
231 return type()->as_ObjectType()->exact_type();
232 }
233 return nullptr;
234 }
235
236 ciType* LoadIndexed::exact_type() const {
237 ciType* array_type = array()->exact_type();
238 if (delayed() == nullptr && array_type != nullptr) {
239 assert(array_type->is_array_klass(), "what else?");
240 ciArrayKlass* ak = (ciArrayKlass*)array_type;
241
242 if (ak->element_type()->is_instance_klass()) {
243 ciInstanceKlass* ik = (ciInstanceKlass*)ak->element_type();
244 if (ik->is_loaded() && ik->is_final()) {
245 return ik;
246 }
247 }
248 }
249 return Instruction::exact_type();
250 }
251
252 ciType* LoadIndexed::declared_type() const {
253 if (delayed() != nullptr) {
254 return delayed()->field()->type();
255 }
256 ciType* array_type = array()->declared_type();
257 if (array_type == nullptr || !array_type->is_loaded()) {
258 return nullptr;
259 }
260 assert(array_type->is_array_klass(), "what else?");
261 ciArrayKlass* ak = (ciArrayKlass*)array_type;
262 return ak->element_type();
263 }
264
265 bool StoreIndexed::is_exact_flat_array_store() const {
266 if (array()->is_loaded_flat_array() && value()->as_Constant() == nullptr && value()->declared_type() != nullptr) {
267 ciKlass* element_klass = array()->declared_type()->as_flat_array_klass()->element_klass();
268 ciKlass* actual_klass = value()->declared_type()->as_klass();
269
270 // The following check can fail with inlining:
271 // void test45_inline(Object[] oa, Object o, int index) { oa[index] = o; }
272 // void test45(MyValue1[] va, int index, MyValue2 v) { test45_inline(va, v, index); }
273 if (element_klass == actual_klass) {
274 return true;
275 }
276 }
277 return false;
278 }
279
280 ciType* LoadField::declared_type() const {
281 return field()->type();
282 }
283
284
285 ciType* NewTypeArray::exact_type() const {
286 return ciTypeArrayKlass::make(elt_type());
287 }
288
289 ciType* NewObjectArray::exact_type() const {
290 return ciArrayKlass::make(klass());
291 }
292
293 ciType* NewMultiArray::exact_type() const {
294 return _klass;
295 }
296
297 ciType* NewArray::declared_type() const {
298 return exact_type();
299 }
300
301 ciType* NewInstance::exact_type() const {
302 return klass();
303 }
304
305 ciType* NewInstance::declared_type() const {
306 return exact_type();
307 }
308
309 ciType* CheckCast::declared_type() const {
310 return klass();
311 }
312
313 // Implementation of ArithmeticOp
314
315 bool ArithmeticOp::is_commutative() const {
316 switch (op()) {
317 case Bytecodes::_iadd: // fall through
318 case Bytecodes::_ladd: // fall through
319 case Bytecodes::_fadd: // fall through
320 case Bytecodes::_dadd: // fall through
321 case Bytecodes::_imul: // fall through
322 case Bytecodes::_lmul: // fall through
323 case Bytecodes::_fmul: // fall through
324 case Bytecodes::_dmul: return true;
325 default : return false;
326 }
327 }
328
329
330 bool ArithmeticOp::can_trap() const {
331 switch (op()) {
332 case Bytecodes::_idiv: // fall through
333 case Bytecodes::_ldiv: // fall through
334 case Bytecodes::_irem: // fall through
335 case Bytecodes::_lrem: return true;
336 default : return false;
337 }
338 }
339
340
341 // Implementation of LogicOp
342
343 bool LogicOp::is_commutative() const {
344 #ifdef ASSERT
345 switch (op()) {
346 case Bytecodes::_iand: // fall through
347 case Bytecodes::_land: // fall through
348 case Bytecodes::_ior : // fall through
349 case Bytecodes::_lor : // fall through
350 case Bytecodes::_ixor: // fall through
351 case Bytecodes::_lxor: break;
352 default : ShouldNotReachHere(); break;
353 }
354 #endif
355 // all LogicOps are commutative
356 return true;
357 }
358
359
360 // Implementation of IfOp
361
362 bool IfOp::is_commutative() const {
363 return cond() == eql || cond() == neq;
364 }
365
366
367 // Implementation of StateSplit
368
369 void StateSplit::substitute(BlockList& list, BlockBegin* old_block, BlockBegin* new_block) {
370 NOT_PRODUCT(bool assigned = false;)
371 for (int i = 0; i < list.length(); i++) {
372 BlockBegin** b = list.adr_at(i);
373 if (*b == old_block) {
374 *b = new_block;
375 NOT_PRODUCT(assigned = true;)
376 }
377 }
378 assert(assigned == true, "should have assigned at least once");
379 }
380
381
382 IRScope* StateSplit::scope() const {
383 return _state->scope();
384 }
385
386
387 void StateSplit::state_values_do(ValueVisitor* f) {
388 Instruction::state_values_do(f);
389 if (state() != nullptr) state()->values_do(f);
390 }
391
392
393 void BlockBegin::state_values_do(ValueVisitor* f) {
394 StateSplit::state_values_do(f);
395
396 if (is_set(BlockBegin::exception_entry_flag)) {
397 for (int i = 0; i < number_of_exception_states(); i++) {
398 exception_state_at(i)->values_do(f);
399 }
400 }
401 }
402
403
404 StoreField::StoreField(Value obj, int offset, ciField* field, Value value, bool is_static,
405 ValueStack* state_before, bool needs_patching)
406 : AccessField(obj, offset, field, is_static, state_before, needs_patching)
407 , _value(value)
408 , _enclosing_field(nullptr)
409 {
410 set_flag(NeedsWriteBarrierFlag, as_ValueType(field_type())->is_object());
411 #ifdef ASSERT
412 AssertValues assert_value;
413 values_do(&assert_value);
414 #endif
415 pin();
416 }
417
418 StoreIndexed::StoreIndexed(Value array, Value index, Value length, BasicType elt_type, Value value,
419 ValueStack* state_before, bool check_boolean, bool mismatched)
420 : AccessIndexed(array, index, length, elt_type, state_before, mismatched)
421 , _value(value), _check_boolean(check_boolean)
422 {
423 set_flag(NeedsWriteBarrierFlag, (as_ValueType(elt_type)->is_object()));
424 set_flag(NeedsStoreCheckFlag, (as_ValueType(elt_type)->is_object()));
425 #ifdef ASSERT
426 AssertValues assert_value;
427 values_do(&assert_value);
428 #endif
429 pin();
430 }
431
432
433 // Implementation of Invoke
434
435
436 Invoke::Invoke(Bytecodes::Code code, ValueType* result_type, Value recv, Values* args,
437 ciMethod* target, ValueStack* state_before)
438 : StateSplit(result_type, state_before)
439 , _code(code)
440 , _recv(recv)
441 , _args(args)
442 , _target(target)
443 {
444 set_flag(TargetIsLoadedFlag, target->is_loaded());
445 set_flag(TargetIsFinalFlag, target_is_loaded() && target->is_final_method());
446
447 assert(args != nullptr, "args must exist");
448 #ifdef ASSERT
449 AssertValues assert_value;
450 values_do(&assert_value);
451 #endif
452
453 // provide an initial guess of signature size.
454 _signature = new BasicTypeList(number_of_arguments() + (has_receiver() ? 1 : 0));
455 if (has_receiver()) {
456 _signature->append(as_BasicType(receiver()->type()));
457 }
458 for (int i = 0; i < number_of_arguments(); i++) {
459 Value v = argument_at(i);
460 ValueType* t = v->type();
461 BasicType bt = as_BasicType(t);
462 _signature->append(bt);
463 }
464 }
465
466
467 void Invoke::state_values_do(ValueVisitor* f) {
468 StateSplit::state_values_do(f);
469 if (state_before() != nullptr) state_before()->values_do(f);
470 if (state() != nullptr) state()->values_do(f);
471 }
472
473 ciType* Invoke::declared_type() const {
474 ciSignature* declared_signature = state()->scope()->method()->get_declared_signature_at_bci(state()->bci());
475 ciType *t = declared_signature->return_type();
476 assert(t->basic_type() != T_VOID, "need return value of void method?");
477 return t;
478 }
479
480 // Implementation of Constant
481 intx Constant::hash() const {
482 if (state_before() == nullptr) {
483 switch (type()->tag()) {
484 case intTag:
485 return HASH2(name(), type()->as_IntConstant()->value());
486 case addressTag:
487 return HASH2(name(), type()->as_AddressConstant()->value());
488 case longTag:
489 {
490 jlong temp = type()->as_LongConstant()->value();
491 return HASH3(name(), high(temp), low(temp));
492 }
493 case floatTag:
494 return HASH2(name(), jint_cast(type()->as_FloatConstant()->value()));
495 case doubleTag:
496 {
497 jlong temp = jlong_cast(type()->as_DoubleConstant()->value());
498 return HASH3(name(), high(temp), low(temp));
499 }
500 case objectTag:
501 assert(type()->as_ObjectType()->is_loaded(), "can't handle unloaded values");
502 return HASH2(name(), type()->as_ObjectType()->constant_value());
503 case metaDataTag:
504 assert(type()->as_MetadataType()->is_loaded(), "can't handle unloaded values");
505 return HASH2(name(), type()->as_MetadataType()->constant_value());
506 default:
507 ShouldNotReachHere();
508 }
509 }
510 return 0;
511 }
512
513 bool Constant::is_equal(Value v) const {
514 if (v->as_Constant() == nullptr) return false;
515
516 switch (type()->tag()) {
517 case intTag:
518 {
519 IntConstant* t1 = type()->as_IntConstant();
520 IntConstant* t2 = v->type()->as_IntConstant();
521 return (t1 != nullptr && t2 != nullptr &&
522 t1->value() == t2->value());
523 }
524 case longTag:
525 {
526 LongConstant* t1 = type()->as_LongConstant();
527 LongConstant* t2 = v->type()->as_LongConstant();
528 return (t1 != nullptr && t2 != nullptr &&
529 t1->value() == t2->value());
530 }
531 case floatTag:
532 {
533 FloatConstant* t1 = type()->as_FloatConstant();
534 FloatConstant* t2 = v->type()->as_FloatConstant();
535 return (t1 != nullptr && t2 != nullptr &&
536 jint_cast(t1->value()) == jint_cast(t2->value()));
537 }
538 case doubleTag:
539 {
540 DoubleConstant* t1 = type()->as_DoubleConstant();
541 DoubleConstant* t2 = v->type()->as_DoubleConstant();
542 return (t1 != nullptr && t2 != nullptr &&
543 jlong_cast(t1->value()) == jlong_cast(t2->value()));
544 }
545 case objectTag:
546 {
547 ObjectType* t1 = type()->as_ObjectType();
548 ObjectType* t2 = v->type()->as_ObjectType();
549 return (t1 != nullptr && t2 != nullptr &&
550 t1->is_loaded() && t2->is_loaded() &&
551 t1->constant_value() == t2->constant_value());
552 }
553 case metaDataTag:
554 {
555 MetadataType* t1 = type()->as_MetadataType();
556 MetadataType* t2 = v->type()->as_MetadataType();
557 return (t1 != nullptr && t2 != nullptr &&
558 t1->is_loaded() && t2->is_loaded() &&
559 t1->constant_value() == t2->constant_value());
560 }
561 default:
562 return false;
563 }
564 }
565
566 Constant::CompareResult Constant::compare(Instruction::Condition cond, Value right) const {
567 Constant* rc = right->as_Constant();
568 // other is not a constant
569 if (rc == nullptr) return not_comparable;
570
571 ValueType* lt = type();
572 ValueType* rt = rc->type();
573 // different types
574 if (lt->base() != rt->base()) return not_comparable;
575 switch (lt->tag()) {
576 case intTag: {
577 int x = lt->as_IntConstant()->value();
578 int y = rt->as_IntConstant()->value();
579 switch (cond) {
580 case If::eql: return x == y ? cond_true : cond_false;
581 case If::neq: return x != y ? cond_true : cond_false;
582 case If::lss: return x < y ? cond_true : cond_false;
583 case If::leq: return x <= y ? cond_true : cond_false;
584 case If::gtr: return x > y ? cond_true : cond_false;
585 case If::geq: return x >= y ? cond_true : cond_false;
586 default : break;
587 }
588 break;
589 }
590 case longTag: {
591 jlong x = lt->as_LongConstant()->value();
592 jlong y = rt->as_LongConstant()->value();
593 switch (cond) {
594 case If::eql: return x == y ? cond_true : cond_false;
595 case If::neq: return x != y ? cond_true : cond_false;
596 case If::lss: return x < y ? cond_true : cond_false;
597 case If::leq: return x <= y ? cond_true : cond_false;
598 case If::gtr: return x > y ? cond_true : cond_false;
599 case If::geq: return x >= y ? cond_true : cond_false;
600 default : break;
601 }
602 break;
603 }
604 case objectTag: {
605 ciObject* xvalue = lt->as_ObjectType()->constant_value();
606 ciObject* yvalue = rt->as_ObjectType()->constant_value();
607 assert(xvalue != nullptr && yvalue != nullptr, "not constants");
608 if (xvalue->is_loaded() && yvalue->is_loaded()) {
609 switch (cond) {
610 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
611 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
612 default : break;
613 }
614 }
615 break;
616 }
617 case metaDataTag: {
618 ciMetadata* xvalue = lt->as_MetadataType()->constant_value();
619 ciMetadata* yvalue = rt->as_MetadataType()->constant_value();
620 assert(xvalue != nullptr && yvalue != nullptr, "not constants");
621 if (xvalue->is_loaded() && yvalue->is_loaded()) {
622 switch (cond) {
623 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
624 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
625 default : break;
626 }
627 }
628 break;
629 }
630 default:
631 break;
632 }
633 return not_comparable;
634 }
635
636
637 // Implementation of BlockBegin
638
639 void BlockBegin::set_end(BlockEnd* new_end) { // Assumes that no predecessor of new_end still has it as its successor
640 assert(new_end != nullptr, "Should not reset block new_end to null");
641 if (new_end == _end) return;
642
643 // Remove this block as predecessor of its current successors
644 if (_end != nullptr) {
645 for (int i = 0; i < number_of_sux(); i++) {
646 sux_at(i)->remove_predecessor(this);
647 }
648 }
649
650 _end = new_end;
651
652 // Add this block as predecessor of its new successors
653 for (int i = 0; i < number_of_sux(); i++) {
654 sux_at(i)->add_predecessor(this);
655 }
656 }
657
658
659 void BlockBegin::disconnect_edge(BlockBegin* from, BlockBegin* to) {
660 // disconnect any edges between from and to
661 #ifndef PRODUCT
662 if (PrintIR && Verbose) {
663 tty->print_cr("Disconnected edge B%d -> B%d", from->block_id(), to->block_id());
664 }
665 #endif
666 for (int s = 0; s < from->number_of_sux();) {
667 BlockBegin* sux = from->sux_at(s);
668 if (sux == to) {
669 int index = sux->_predecessors.find(from);
670 if (index >= 0) {
671 sux->_predecessors.remove_at(index);
672 }
673 from->end()->remove_sux_at(s);
674 } else {
675 s++;
676 }
677 }
678 }
679
680
681 void BlockBegin::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
682 // modify predecessors before substituting successors
683 for (int i = 0; i < number_of_sux(); i++) {
684 if (sux_at(i) == old_sux) {
685 // remove old predecessor before adding new predecessor
686 // otherwise there is a dead predecessor in the list
687 new_sux->remove_predecessor(old_sux);
688 new_sux->add_predecessor(this);
689 }
690 }
691 old_sux->remove_predecessor(this);
692 end()->substitute_sux(old_sux, new_sux);
693 }
694
695
696
697 // In general it is not possible to calculate a value for the field "depth_first_number"
698 // of the inserted block, without recomputing the values of the other blocks
699 // in the CFG. Therefore the value of "depth_first_number" in BlockBegin becomes meaningless.
700 BlockBegin* BlockBegin::insert_block_between(BlockBegin* sux) {
701 assert(!sux->is_set(critical_edge_split_flag), "sanity check");
702
703 int bci = sux->bci();
704 // critical edge splitting may introduce a goto after a if and array
705 // bound check elimination may insert a predicate between the if and
706 // goto. The bci of the goto can't be the one of the if otherwise
707 // the state and bci are inconsistent and a deoptimization triggered
708 // by the predicate would lead to incorrect execution/a crash.
709 BlockBegin* new_sux = new BlockBegin(bci);
710
711 // mark this block (special treatment when block order is computed)
712 new_sux->set(critical_edge_split_flag);
713
714 // This goto is not a safepoint.
715 Goto* e = new Goto(sux, false);
716 new_sux->set_next(e, bci);
717 new_sux->set_end(e);
718 // setup states
719 ValueStack* s = end()->state();
720 new_sux->set_state(s->copy(s->kind(), bci));
721 e->set_state(s->copy(s->kind(), bci));
722 assert(new_sux->state()->locals_size() == s->locals_size(), "local size mismatch!");
723 assert(new_sux->state()->stack_size() == s->stack_size(), "stack size mismatch!");
724 assert(new_sux->state()->locks_size() == s->locks_size(), "locks size mismatch!");
725
726 // link predecessor to new block
727 end()->substitute_sux(sux, new_sux);
728
729 // The ordering needs to be the same, so remove the link that the
730 // set_end call above added and substitute the new_sux for this
731 // block.
732 sux->remove_predecessor(new_sux);
733
734 // the successor could be the target of a switch so it might have
735 // multiple copies of this predecessor, so substitute the new_sux
736 // for the first and delete the rest.
737 bool assigned = false;
738 BlockList& list = sux->_predecessors;
739 for (int i = 0; i < list.length(); i++) {
740 BlockBegin** b = list.adr_at(i);
741 if (*b == this) {
742 if (assigned) {
743 list.remove_at(i);
744 // reprocess this index
745 i--;
746 } else {
747 assigned = true;
748 *b = new_sux;
749 }
750 // link the new block back to it's predecessors.
751 new_sux->add_predecessor(this);
752 }
753 }
754 assert(assigned == true, "should have assigned at least once");
755 return new_sux;
756 }
757
758
759 void BlockBegin::add_predecessor(BlockBegin* pred) {
760 _predecessors.append(pred);
761 }
762
763
764 void BlockBegin::remove_predecessor(BlockBegin* pred) {
765 int idx;
766 while ((idx = _predecessors.find(pred)) >= 0) {
767 _predecessors.remove_at(idx);
768 }
769 }
770
771
772 void BlockBegin::add_exception_handler(BlockBegin* b) {
773 assert(b != nullptr && (b->is_set(exception_entry_flag)), "exception handler must exist");
774 // add only if not in the list already
775 if (!_exception_handlers.contains(b)) _exception_handlers.append(b);
776 }
777
778 int BlockBegin::add_exception_state(ValueStack* state) {
779 assert(is_set(exception_entry_flag), "only for xhandlers");
780 if (_exception_states == nullptr) {
781 _exception_states = new ValueStackStack(4);
782 }
783 _exception_states->append(state);
784 return _exception_states->length() - 1;
785 }
786
787
788 void BlockBegin::iterate_preorder(boolArray& mark, BlockClosure* closure) {
789 if (!mark.at(block_id())) {
790 mark.at_put(block_id(), true);
791 closure->block_do(this);
792 BlockEnd* e = end(); // must do this after block_do because block_do may change it!
793 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_preorder(mark, closure); }
794 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_preorder(mark, closure); }
795 }
796 }
797
798
799 void BlockBegin::iterate_postorder(boolArray& mark, BlockClosure* closure) {
800 if (!mark.at(block_id())) {
801 mark.at_put(block_id(), true);
802 BlockEnd* e = end();
803 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_postorder(mark, closure); }
804 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_postorder(mark, closure); }
805 closure->block_do(this);
806 }
807 }
808
809
810 void BlockBegin::iterate_preorder(BlockClosure* closure) {
811 int mark_len = number_of_blocks();
812 boolArray mark(mark_len, mark_len, false);
813 iterate_preorder(mark, closure);
814 }
815
816
817 void BlockBegin::iterate_postorder(BlockClosure* closure) {
818 int mark_len = number_of_blocks();
819 boolArray mark(mark_len, mark_len, false);
820 iterate_postorder(mark, closure);
821 }
822
823
824 void BlockBegin::block_values_do(ValueVisitor* f) {
825 for (Instruction* n = this; n != nullptr; n = n->next()) n->values_do(f);
826 }
827
828
829 #ifndef PRODUCT
830 #define TRACE_PHI(code) if (PrintPhiFunctions) { code; }
831 #else
832 #define TRACE_PHI(coce)
833 #endif
834
835
836 bool BlockBegin::try_merge(ValueStack* new_state, bool has_irreducible_loops) {
837 TRACE_PHI(tty->print_cr("********** try_merge for block B%d", block_id()));
838
839 // local variables used for state iteration
840 int index;
841 Value new_value, existing_value;
842
843 ValueStack* existing_state = state();
844 if (existing_state == nullptr) {
845 TRACE_PHI(tty->print_cr("first call of try_merge for this block"));
846
847 if (is_set(BlockBegin::was_visited_flag)) {
848 // this actually happens for complicated jsr/ret structures
849 return false; // BAILOUT in caller
850 }
851
852 // copy state because it is altered
853 new_state = new_state->copy(ValueStack::BlockBeginState, bci());
854
855 // Use method liveness to invalidate dead locals
856 MethodLivenessResult liveness = new_state->scope()->method()->liveness_at_bci(bci());
857 if (liveness.is_valid()) {
858 assert((int)liveness.size() == new_state->locals_size(), "error in use of liveness");
859
860 for_each_local_value(new_state, index, new_value) {
861 if (!liveness.at(index) || new_value->type()->is_illegal()) {
862 new_state->invalidate_local(index);
863 TRACE_PHI(tty->print_cr("invalidating dead local %d", index));
864 }
865 }
866 }
867
868 if (is_set(BlockBegin::parser_loop_header_flag)) {
869 TRACE_PHI(tty->print_cr("loop header block, initializing phi functions"));
870
871 for_each_stack_value(new_state, index, new_value) {
872 new_state->setup_phi_for_stack(this, index);
873 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));
874 }
875
876 BitMap& requires_phi_function = new_state->scope()->requires_phi_function();
877 for_each_local_value(new_state, index, new_value) {
878 bool requires_phi = requires_phi_function.at(index) || (new_value->type()->is_double_word() && requires_phi_function.at(index + 1));
879 if (requires_phi || !SelectivePhiFunctions || has_irreducible_loops) {
880 new_state->setup_phi_for_local(this, index);
881 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));
882 }
883 }
884 }
885
886 // initialize state of block
887 set_state(new_state);
888
889 } else if (existing_state->is_same(new_state)) {
890 TRACE_PHI(tty->print_cr("existing state found"));
891
892 assert(existing_state->scope() == new_state->scope(), "not matching");
893 assert(existing_state->locals_size() == new_state->locals_size(), "not matching");
894 assert(existing_state->stack_size() == new_state->stack_size(), "not matching");
895
896 if (is_set(BlockBegin::was_visited_flag)) {
897 TRACE_PHI(tty->print_cr("loop header block, phis must be present"));
898
899 if (!is_set(BlockBegin::parser_loop_header_flag)) {
900 // this actually happens for complicated jsr/ret structures
901 return false; // BAILOUT in caller
902 }
903
904 for_each_local_value(existing_state, index, existing_value) {
905 Value new_value = new_state->local_at(index);
906 if (new_value == nullptr || new_value->type()->tag() != existing_value->type()->tag()) {
907 Phi* existing_phi = existing_value->as_Phi();
908 if (existing_phi == nullptr) {
909 return false; // BAILOUT in caller
910 }
911 // Invalidate the phi function here. This case is very rare except for
912 // JVMTI capability "can_access_local_variables".
913 // In really rare cases we will bail out in LIRGenerator::move_to_phi.
914 existing_phi->make_illegal();
915 existing_state->invalidate_local(index);
916 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
917 }
918
919 if (existing_value != new_state->local_at(index) && existing_value->as_Phi() == nullptr) {
920 TRACE_PHI(tty->print_cr("required phi for local %d is missing, irreducible loop?", index));
921 return false; // BAILOUT in caller
922 }
923 }
924
925 #ifdef ASSERT
926 // check that all necessary phi functions are present
927 for_each_stack_value(existing_state, index, existing_value) {
928 assert(existing_value->as_Phi() != nullptr && existing_value->as_Phi()->block() == this, "phi function required");
929 }
930 for_each_local_value(existing_state, index, existing_value) {
931 assert(existing_value == new_state->local_at(index) || (existing_value->as_Phi() != nullptr && existing_value->as_Phi()->as_Phi()->block() == this), "phi function required");
932 }
933 #endif
934
935 } else {
936 TRACE_PHI(tty->print_cr("creating phi functions on demand"));
937
938 // create necessary phi functions for stack
939 for_each_stack_value(existing_state, index, existing_value) {
940 Value new_value = new_state->stack_at(index);
941 Phi* existing_phi = existing_value->as_Phi();
942
943 if (new_value != existing_value && (existing_phi == nullptr || existing_phi->block() != this)) {
944 existing_state->setup_phi_for_stack(this, index);
945 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));
946 }
947 }
948
949 // create necessary phi functions for locals
950 for_each_local_value(existing_state, index, existing_value) {
951 Value new_value = new_state->local_at(index);
952 Phi* existing_phi = existing_value->as_Phi();
953
954 if (new_value == nullptr || new_value->type()->tag() != existing_value->type()->tag()) {
955 existing_state->invalidate_local(index);
956 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
957 } else if (new_value != existing_value && (existing_phi == nullptr || existing_phi->block() != this)) {
958 existing_state->setup_phi_for_local(this, index);
959 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));
960 }
961 }
962 }
963
964 assert(existing_state->caller_state() == new_state->caller_state(), "caller states must be equal");
965
966 } else {
967 assert(false, "stack or locks not matching (invalid bytecodes)");
968 return false;
969 }
970
971 TRACE_PHI(tty->print_cr("********** try_merge for block B%d successful", block_id()));
972
973 return true;
974 }
975
976
977 #ifndef PRODUCT
978 void BlockBegin::print_block() {
979 InstructionPrinter ip;
980 print_block(ip, false);
981 }
982
983
984 void BlockBegin::print_block(InstructionPrinter& ip, bool live_only) {
985 ip.print_instr(this); tty->cr();
986 ip.print_stack(this->state()); tty->cr();
987 ip.print_inline_level(this);
988 ip.print_head();
989 for (Instruction* n = next(); n != nullptr; n = n->next()) {
990 if (!live_only || n->is_pinned() || n->use_count() > 0) {
991 ip.print_line(n);
992 }
993 }
994 tty->cr();
995 }
996 #endif // PRODUCT
997
998
999 // Implementation of BlockList
1000
1001 void BlockList::iterate_forward (BlockClosure* closure) {
1002 const int l = length();
1003 for (int i = 0; i < l; i++) closure->block_do(at(i));
1004 }
1005
1006
1007 void BlockList::iterate_backward(BlockClosure* closure) {
1008 for (int i = length() - 1; i >= 0; i--) closure->block_do(at(i));
1009 }
1010
1011
1012 void BlockList::values_do(ValueVisitor* f) {
1013 for (int i = length() - 1; i >= 0; i--) at(i)->block_values_do(f);
1014 }
1015
1016
1017 #ifndef PRODUCT
1018 void BlockList::print(bool cfg_only, bool live_only) {
1019 InstructionPrinter ip;
1020 for (int i = 0; i < length(); i++) {
1021 BlockBegin* block = at(i);
1022 if (cfg_only) {
1023 ip.print_instr(block); tty->cr();
1024 } else {
1025 block->print_block(ip, live_only);
1026 }
1027 }
1028 }
1029 #endif // PRODUCT
1030
1031
1032 // Implementation of BlockEnd
1033
1034 void BlockEnd::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
1035 substitute(*_sux, old_sux, new_sux);
1036 }
1037
1038 // Implementation of Phi
1039
1040 // Normal phi functions take their operands from the last instruction of the
1041 // predecessor. Special handling is needed for xhanlder entries because there
1042 // the state of arbitrary instructions are needed.
1043
1044 Value Phi::operand_at(int i) const {
1045 ValueStack* state;
1046 if (_block->is_set(BlockBegin::exception_entry_flag)) {
1047 state = _block->exception_state_at(i);
1048 } else {
1049 state = _block->pred_at(i)->end()->state();
1050 }
1051 assert(state != nullptr, "");
1052
1053 if (is_local()) {
1054 return state->local_at(local_index());
1055 } else {
1056 return state->stack_at(stack_index());
1057 }
1058 }
1059
1060
1061 int Phi::operand_count() const {
1062 if (_block->is_set(BlockBegin::exception_entry_flag)) {
1063 return _block->number_of_exception_states();
1064 } else {
1065 return _block->number_of_preds();
1066 }
1067 }
1068
1069 #ifdef ASSERT
1070 // Constructor of Assert
1071 Assert::Assert(Value x, Condition cond, bool unordered_is_true, Value y) : Instruction(illegalType)
1072 , _x(x)
1073 , _cond(cond)
1074 , _y(y)
1075 {
1076 set_flag(UnorderedIsTrueFlag, unordered_is_true);
1077 assert(x->type()->tag() == y->type()->tag(), "types must match");
1078 pin();
1079
1080 stringStream strStream;
1081 Compilation::current()->method()->print_name(&strStream);
1082
1083 stringStream strStream1;
1084 InstructionPrinter ip1(1, &strStream1);
1085 ip1.print_instr(x);
1086
1087 stringStream strStream2;
1088 InstructionPrinter ip2(1, &strStream2);
1089 ip2.print_instr(y);
1090
1091 stringStream ss;
1092 ss.print("Assertion %s %s %s in method %s", strStream1.freeze(), ip2.cond_name(cond), strStream2.freeze(), strStream.freeze());
1093
1094 _message = ss.as_string();
1095 }
1096 #endif
1097
1098 void RangeCheckPredicate::check_state() {
1099 assert(state()->kind() != ValueStack::EmptyExceptionState && state()->kind() != ValueStack::ExceptionState, "will deopt with empty state");
1100 }
1101
1102 void ProfileInvoke::state_values_do(ValueVisitor* f) {
1103 if (state() != nullptr) state()->values_do(f);
1104 }
1105