1 /*
2 * Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "c1/c1_IR.hpp"
27 #include "c1/c1_Instruction.hpp"
28 #include "c1/c1_InstructionPrinter.hpp"
29 #include "c1/c1_ValueStack.hpp"
30 #include "ci/ciObjArrayKlass.hpp"
31 #include "ci/ciTypeArrayKlass.hpp"
32 #include "ci/ciValueArrayKlass.hpp"
33 #include "ci/ciValueKlass.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 != NULL && (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 = NULL;
85 }
86 }
87
88 // Prev without need to have BlockBegin
89 Instruction* Instruction::prev() {
90 Instruction* p = NULL;
91 Instruction* q = block();
92 while (q != this) {
93 assert(q != NULL, "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() != NULL) {
102 state_before()->values_do(f);
103 }
104 if (exception_state() != NULL){
105 exception_state()->values_do(f);
106 }
107 }
108
109 ciType* Instruction::exact_type() const {
110 ciType* t = declared_type();
111 if (t != NULL && t->is_klass()) {
112 return t->as_klass()->exact_klass();
113 }
114 return NULL;
115 }
116
117
118 // FIXME -- make this obsolete. Use maybe_flattened_array() or check_flattened_array() instead.
119 bool Instruction::is_flattened_array() const {
120 if (ValueArrayFlatten) {
121 ciType* type = declared_type();
122 if (type != NULL && type->is_value_array_klass()) {
123 ciValueKlass* element_klass = type->as_value_array_klass()->element_klass()->as_value_klass();
124 if (!element_klass->is_loaded() || element_klass->flatten_array()) {
125 // Assume that all unloaded value arrays are not flattenable. If they
126 // turn out to be flattenable, we deoptimize on aaload/aastore.
127 // ^^^^ uugh -- this is ugly!
128 return true;
129 }
130 }
131 }
132
133 return false;
134 }
135
136 bool Instruction::is_loaded_flattened_array() const {
137 if (ValueArrayFlatten) {
138 ciType* type = declared_type();
139 if (type != NULL && type->is_value_array_klass()) {
140 ciValueKlass* element_klass = type->as_value_array_klass()->element_klass()->as_value_klass();
141 if (element_klass->is_loaded() && element_klass->flatten_array()) {
142 return true;
143 }
144 }
145 }
146
147 return false;
148 }
149
150 bool Instruction::maybe_flattened_array() {
151 if (ValueArrayFlatten) {
152 ciType* type = declared_type();
153 if (type != NULL) {
154 if (type->is_value_array_klass()) {
155 ciValueKlass* element_klass = type->as_value_array_klass()->element_klass()->as_value_klass();
156 if (!element_klass->is_loaded() || element_klass->flatten_array()) {
157 // For unloaded value arrays, we will add a runtime check for flat-ness.
158 return true;
159 }
160 } else if (type->is_obj_array_klass()) {
161 ciKlass* element_klass = type->as_obj_array_klass()->element_klass();
162 if (element_klass->is_java_lang_Object() || element_klass->is_interface()) {
163 // Array covariance:
164 // (ValueType[] <: Object[])
165 // (ValueType[] <: <any interface>[])
166 // We will add a runtime check for flat-ness.
167 return true;
168 }
169 }
170 } else if (as_Phi() != NULL) {
171 // Type info gets lost during Phi merging, but we might be storing into a
172 // flattened array, so we should do a runtime check.
173 return true;
174 }
175 }
176
177 return false;
178 }
179
180 #ifndef PRODUCT
181 void Instruction::check_state(ValueStack* state) {
182 if (state != NULL) {
183 state->verify();
184 }
185 }
186
187
188 void Instruction::print() {
189 InstructionPrinter ip;
190 print(ip);
191 }
192
193
194 void Instruction::print_line() {
195 InstructionPrinter ip;
196 ip.print_line(this);
197 }
198
199
200 void Instruction::print(InstructionPrinter& ip) {
201 ip.print_head();
202 ip.print_line(this);
203 tty->cr();
204 }
205 #endif // PRODUCT
206
207
208 // perform constant and interval tests on index value
209 bool AccessIndexed::compute_needs_range_check() {
210 if (length()) {
211 Constant* clength = length()->as_Constant();
212 Constant* cindex = index()->as_Constant();
213 if (clength && cindex) {
214 IntConstant* l = clength->type()->as_IntConstant();
215 IntConstant* i = cindex->type()->as_IntConstant();
216 if (l && i && i->value() < l->value() && i->value() >= 0) {
217 return false;
218 }
219 }
220 }
221
222 if (!this->check_flag(NeedsRangeCheckFlag)) {
223 return false;
224 }
225
226 return true;
227 }
228
229
230 ciType* Constant::exact_type() const {
231 if (type()->is_object() && type()->as_ObjectType()->is_loaded()) {
232 return type()->as_ObjectType()->exact_type();
233 }
234 return NULL;
235 }
236
237 ciType* LoadIndexed::exact_type() const {
238 ciType* array_type = array()->exact_type();
239 if (array_type != NULL) {
240 assert(array_type->is_array_klass(), "what else?");
241 ciArrayKlass* ak = (ciArrayKlass*)array_type;
242
243 if (ak->element_type()->is_instance_klass()) {
244 ciInstanceKlass* ik = (ciInstanceKlass*)ak->element_type();
245 if (ik->is_loaded() && ik->is_final()) {
246 return ik;
247 }
248 }
249 }
250 return Instruction::exact_type();
251 }
252
253
254 ciType* LoadIndexed::declared_type() const {
255 ciType* array_type = array()->declared_type();
256 if (array_type == NULL || !array_type->is_loaded()) {
257 return NULL;
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_flattened_array_store() const {
265 if (array()->is_loaded_flattened_array() && value()->as_Constant() == NULL) {
266 ciKlass* element_klass = array()->declared_type()->as_value_array_klass()->element_klass();
267 ciKlass* actual_klass = value()->declared_type()->as_klass();
268 if (element_klass == actual_klass) {
269 return true;
270 }
271 }
272 return false;
273 }
274
275 ciType* LoadField::declared_type() const {
276 return field()->type();
277 }
278
279
280 ciType* NewTypeArray::exact_type() const {
281 return ciTypeArrayKlass::make(elt_type());
282 }
283
284 ciType* NewObjectArray::exact_type() const {
285 ciKlass* element_klass = klass();
286 if (element_klass->is_valuetype()) {
287 return ciValueArrayKlass::make(element_klass);
288 } else {
289 return ciObjArrayKlass::make(element_klass);
290 }
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 Value NewValueTypeInstance::depends_on() {
310 if (_depends_on != this) {
311 if (_depends_on->as_NewValueTypeInstance() != NULL) {
312 return _depends_on->as_NewValueTypeInstance()->depends_on();
313 }
314 }
315 return _depends_on;
316 }
317
318 ciType* NewValueTypeInstance::exact_type() const {
319 return klass();
320 }
321
322 ciType* NewValueTypeInstance::declared_type() const {
323 return exact_type();
324 }
325
326 ciType* CheckCast::declared_type() const {
327 return klass();
328 }
329
330 // Implementation of ArithmeticOp
331
332 bool ArithmeticOp::is_commutative() const {
333 switch (op()) {
334 case Bytecodes::_iadd: // fall through
335 case Bytecodes::_ladd: // fall through
336 case Bytecodes::_fadd: // fall through
337 case Bytecodes::_dadd: // fall through
338 case Bytecodes::_imul: // fall through
339 case Bytecodes::_lmul: // fall through
340 case Bytecodes::_fmul: // fall through
341 case Bytecodes::_dmul: return true;
342 default : return false;
343 }
344 }
345
346
347 bool ArithmeticOp::can_trap() const {
348 switch (op()) {
349 case Bytecodes::_idiv: // fall through
350 case Bytecodes::_ldiv: // fall through
351 case Bytecodes::_irem: // fall through
352 case Bytecodes::_lrem: return true;
353 default : return false;
354 }
355 }
356
357
358 // Implementation of LogicOp
359
360 bool LogicOp::is_commutative() const {
361 #ifdef ASSERT
362 switch (op()) {
363 case Bytecodes::_iand: // fall through
364 case Bytecodes::_land: // fall through
365 case Bytecodes::_ior : // fall through
366 case Bytecodes::_lor : // fall through
367 case Bytecodes::_ixor: // fall through
368 case Bytecodes::_lxor: break;
369 default : ShouldNotReachHere(); break;
370 }
371 #endif
372 // all LogicOps are commutative
373 return true;
374 }
375
376
377 // Implementation of IfOp
378
379 bool IfOp::is_commutative() const {
380 return cond() == eql || cond() == neq;
381 }
382
383
384 // Implementation of StateSplit
385
386 void StateSplit::substitute(BlockList& list, BlockBegin* old_block, BlockBegin* new_block) {
387 NOT_PRODUCT(bool assigned = false;)
388 for (int i = 0; i < list.length(); i++) {
389 BlockBegin** b = list.adr_at(i);
390 if (*b == old_block) {
391 *b = new_block;
392 NOT_PRODUCT(assigned = true;)
393 }
394 }
395 assert(assigned == true, "should have assigned at least once");
396 }
397
398
399 IRScope* StateSplit::scope() const {
400 return _state->scope();
401 }
402
403
404 void StateSplit::state_values_do(ValueVisitor* f) {
405 Instruction::state_values_do(f);
406 if (state() != NULL) state()->values_do(f);
407 }
408
409
410 void BlockBegin::state_values_do(ValueVisitor* f) {
411 StateSplit::state_values_do(f);
412
413 if (is_set(BlockBegin::exception_entry_flag)) {
414 for (int i = 0; i < number_of_exception_states(); i++) {
415 exception_state_at(i)->values_do(f);
416 }
417 }
418 }
419
420
421 // Implementation of Invoke
422
423
424 Invoke::Invoke(Bytecodes::Code code, ValueType* result_type, Value recv, Values* args,
425 int vtable_index, ciMethod* target, ValueStack* state_before, bool never_null)
426 : StateSplit(result_type, state_before)
427 , _code(code)
428 , _recv(recv)
429 , _args(args)
430 , _vtable_index(vtable_index)
431 , _target(target)
432 {
433 set_flag(TargetIsLoadedFlag, target->is_loaded());
434 set_flag(TargetIsFinalFlag, target_is_loaded() && target->is_final_method());
435 set_flag(TargetIsStrictfpFlag, target_is_loaded() && target->is_strict());
436 set_never_null(never_null);
437
438 assert(args != NULL, "args must exist");
439 #ifdef ASSERT
440 AssertValues assert_value;
441 values_do(&assert_value);
442 #endif
443
444 // provide an initial guess of signature size.
445 _signature = new BasicTypeList(number_of_arguments() + (has_receiver() ? 1 : 0));
446 if (has_receiver()) {
447 _signature->append(as_BasicType(receiver()->type()));
448 }
449 for (int i = 0; i < number_of_arguments(); i++) {
450 ValueType* t = argument_at(i)->type();
451 BasicType bt = as_BasicType(t);
452 _signature->append(bt);
453 }
454 }
455
456
457 void Invoke::state_values_do(ValueVisitor* f) {
458 StateSplit::state_values_do(f);
459 if (state_before() != NULL) state_before()->values_do(f);
460 if (state() != NULL) state()->values_do(f);
461 }
462
463 ciType* Invoke::declared_type() const {
464 ciSignature* declared_signature = state()->scope()->method()->get_declared_signature_at_bci(state()->bci());
465 ciType *t = declared_signature->return_type();
466 assert(t->basic_type() != T_VOID, "need return value of void method?");
467 return t;
468 }
469
470 // Implementation of Contant
471 intx Constant::hash() const {
472 if (state_before() == NULL) {
473 switch (type()->tag()) {
474 case intTag:
475 return HASH2(name(), type()->as_IntConstant()->value());
476 case addressTag:
477 return HASH2(name(), type()->as_AddressConstant()->value());
478 case longTag:
479 {
480 jlong temp = type()->as_LongConstant()->value();
481 return HASH3(name(), high(temp), low(temp));
482 }
483 case floatTag:
484 return HASH2(name(), jint_cast(type()->as_FloatConstant()->value()));
485 case doubleTag:
486 {
487 jlong temp = jlong_cast(type()->as_DoubleConstant()->value());
488 return HASH3(name(), high(temp), low(temp));
489 }
490 case objectTag:
491 assert(type()->as_ObjectType()->is_loaded(), "can't handle unloaded values");
492 return HASH2(name(), type()->as_ObjectType()->constant_value());
493 case metaDataTag:
494 assert(type()->as_MetadataType()->is_loaded(), "can't handle unloaded values");
495 return HASH2(name(), type()->as_MetadataType()->constant_value());
496 default:
497 ShouldNotReachHere();
498 }
499 }
500 return 0;
501 }
502
503 bool Constant::is_equal(Value v) const {
504 if (v->as_Constant() == NULL) return false;
505
506 switch (type()->tag()) {
507 case intTag:
508 {
509 IntConstant* t1 = type()->as_IntConstant();
510 IntConstant* t2 = v->type()->as_IntConstant();
511 return (t1 != NULL && t2 != NULL &&
512 t1->value() == t2->value());
513 }
514 case longTag:
515 {
516 LongConstant* t1 = type()->as_LongConstant();
517 LongConstant* t2 = v->type()->as_LongConstant();
518 return (t1 != NULL && t2 != NULL &&
519 t1->value() == t2->value());
520 }
521 case floatTag:
522 {
523 FloatConstant* t1 = type()->as_FloatConstant();
524 FloatConstant* t2 = v->type()->as_FloatConstant();
525 return (t1 != NULL && t2 != NULL &&
526 jint_cast(t1->value()) == jint_cast(t2->value()));
527 }
528 case doubleTag:
529 {
530 DoubleConstant* t1 = type()->as_DoubleConstant();
531 DoubleConstant* t2 = v->type()->as_DoubleConstant();
532 return (t1 != NULL && t2 != NULL &&
533 jlong_cast(t1->value()) == jlong_cast(t2->value()));
534 }
535 case objectTag:
536 {
537 ObjectType* t1 = type()->as_ObjectType();
538 ObjectType* t2 = v->type()->as_ObjectType();
539 return (t1 != NULL && t2 != NULL &&
540 t1->is_loaded() && t2->is_loaded() &&
541 t1->constant_value() == t2->constant_value());
542 }
543 case metaDataTag:
544 {
545 MetadataType* t1 = type()->as_MetadataType();
546 MetadataType* t2 = v->type()->as_MetadataType();
547 return (t1 != NULL && t2 != NULL &&
548 t1->is_loaded() && t2->is_loaded() &&
549 t1->constant_value() == t2->constant_value());
550 }
551 default:
552 return false;
553 }
554 }
555
556 Constant::CompareResult Constant::compare(Instruction::Condition cond, Value right) const {
557 Constant* rc = right->as_Constant();
558 // other is not a constant
559 if (rc == NULL) return not_comparable;
560
561 ValueType* lt = type();
562 ValueType* rt = rc->type();
563 // different types
564 if (lt->base() != rt->base()) return not_comparable;
565 switch (lt->tag()) {
566 case intTag: {
567 int x = lt->as_IntConstant()->value();
568 int y = rt->as_IntConstant()->value();
569 switch (cond) {
570 case If::eql: return x == y ? cond_true : cond_false;
571 case If::neq: return x != y ? cond_true : cond_false;
572 case If::lss: return x < y ? cond_true : cond_false;
573 case If::leq: return x <= y ? cond_true : cond_false;
574 case If::gtr: return x > y ? cond_true : cond_false;
575 case If::geq: return x >= y ? cond_true : cond_false;
576 default : break;
577 }
578 break;
579 }
580 case longTag: {
581 jlong x = lt->as_LongConstant()->value();
582 jlong y = rt->as_LongConstant()->value();
583 switch (cond) {
584 case If::eql: return x == y ? cond_true : cond_false;
585 case If::neq: return x != y ? cond_true : cond_false;
586 case If::lss: return x < y ? cond_true : cond_false;
587 case If::leq: return x <= y ? cond_true : cond_false;
588 case If::gtr: return x > y ? cond_true : cond_false;
589 case If::geq: return x >= y ? cond_true : cond_false;
590 default : break;
591 }
592 break;
593 }
594 case objectTag: {
595 ciObject* xvalue = lt->as_ObjectType()->constant_value();
596 ciObject* yvalue = rt->as_ObjectType()->constant_value();
597 assert(xvalue != NULL && yvalue != NULL, "not constants");
598 if (xvalue->is_loaded() && yvalue->is_loaded()) {
599 switch (cond) {
600 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
601 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
602 default : break;
603 }
604 }
605 break;
606 }
607 case metaDataTag: {
608 ciMetadata* xvalue = lt->as_MetadataType()->constant_value();
609 ciMetadata* yvalue = rt->as_MetadataType()->constant_value();
610 assert(xvalue != NULL && yvalue != NULL, "not constants");
611 if (xvalue->is_loaded() && yvalue->is_loaded()) {
612 switch (cond) {
613 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
614 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
615 default : break;
616 }
617 }
618 break;
619 }
620 default:
621 break;
622 }
623 return not_comparable;
624 }
625
626
627 // Implementation of BlockBegin
628
629 void BlockBegin::set_end(BlockEnd* end) {
630 assert(end != NULL, "should not reset block end to NULL");
631 if (end == _end) {
632 return;
633 }
634 clear_end();
635
636 // Set the new end
637 _end = end;
638
639 _successors.clear();
640 // Now reset successors list based on BlockEnd
641 for (int i = 0; i < end->number_of_sux(); i++) {
642 BlockBegin* sux = end->sux_at(i);
643 _successors.append(sux);
644 sux->_predecessors.append(this);
645 }
646 _end->set_begin(this);
647 }
648
649
650 void BlockBegin::clear_end() {
651 // Must make the predecessors/successors match up with the
652 // BlockEnd's notion.
653 if (_end != NULL) {
654 // disconnect from the old end
655 _end->set_begin(NULL);
656
657 // disconnect this block from it's current successors
658 for (int i = 0; i < _successors.length(); i++) {
659 _successors.at(i)->remove_predecessor(this);
660 }
661 _end = NULL;
662 }
663 }
664
665
666 void BlockBegin::disconnect_edge(BlockBegin* from, BlockBegin* to) {
667 // disconnect any edges between from and to
668 #ifndef PRODUCT
669 if (PrintIR && Verbose) {
670 tty->print_cr("Disconnected edge B%d -> B%d", from->block_id(), to->block_id());
671 }
672 #endif
673 for (int s = 0; s < from->number_of_sux();) {
674 BlockBegin* sux = from->sux_at(s);
675 if (sux == to) {
676 int index = sux->_predecessors.find(from);
677 if (index >= 0) {
678 sux->_predecessors.remove_at(index);
679 }
680 from->_successors.remove_at(s);
681 } else {
682 s++;
683 }
684 }
685 }
686
687
688 void BlockBegin::disconnect_from_graph() {
689 // disconnect this block from all other blocks
690 for (int p = 0; p < number_of_preds(); p++) {
691 pred_at(p)->remove_successor(this);
692 }
693 for (int s = 0; s < number_of_sux(); s++) {
694 sux_at(s)->remove_predecessor(this);
695 }
696 }
697
698 void BlockBegin::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
699 // modify predecessors before substituting successors
700 for (int i = 0; i < number_of_sux(); i++) {
701 if (sux_at(i) == old_sux) {
702 // remove old predecessor before adding new predecessor
703 // otherwise there is a dead predecessor in the list
704 new_sux->remove_predecessor(old_sux);
705 new_sux->add_predecessor(this);
706 }
707 }
708 old_sux->remove_predecessor(this);
709 end()->substitute_sux(old_sux, new_sux);
710 }
711
712
713
714 // In general it is not possible to calculate a value for the field "depth_first_number"
715 // of the inserted block, without recomputing the values of the other blocks
716 // in the CFG. Therefore the value of "depth_first_number" in BlockBegin becomes meaningless.
717 BlockBegin* BlockBegin::insert_block_between(BlockBegin* sux) {
718 int bci = sux->bci();
719 // critical edge splitting may introduce a goto after a if and array
720 // bound check elimination may insert a predicate between the if and
721 // goto. The bci of the goto can't be the one of the if otherwise
722 // the state and bci are inconsistent and a deoptimization triggered
723 // by the predicate would lead to incorrect execution/a crash.
724 BlockBegin* new_sux = new BlockBegin(bci);
725
726 // mark this block (special treatment when block order is computed)
727 new_sux->set(critical_edge_split_flag);
728
729 // This goto is not a safepoint.
730 Goto* e = new Goto(sux, false);
731 new_sux->set_next(e, bci);
732 new_sux->set_end(e);
733 // setup states
734 ValueStack* s = end()->state();
735 new_sux->set_state(s->copy(s->kind(), bci));
736 e->set_state(s->copy(s->kind(), bci));
737 assert(new_sux->state()->locals_size() == s->locals_size(), "local size mismatch!");
738 assert(new_sux->state()->stack_size() == s->stack_size(), "stack size mismatch!");
739 assert(new_sux->state()->locks_size() == s->locks_size(), "locks size mismatch!");
740
741 // link predecessor to new block
742 end()->substitute_sux(sux, new_sux);
743
744 // The ordering needs to be the same, so remove the link that the
745 // set_end call above added and substitute the new_sux for this
746 // block.
747 sux->remove_predecessor(new_sux);
748
749 // the successor could be the target of a switch so it might have
750 // multiple copies of this predecessor, so substitute the new_sux
751 // for the first and delete the rest.
752 bool assigned = false;
753 BlockList& list = sux->_predecessors;
754 for (int i = 0; i < list.length(); i++) {
755 BlockBegin** b = list.adr_at(i);
756 if (*b == this) {
757 if (assigned) {
758 list.remove_at(i);
759 // reprocess this index
760 i--;
761 } else {
762 assigned = true;
763 *b = new_sux;
764 }
765 // link the new block back to it's predecessors.
766 new_sux->add_predecessor(this);
767 }
768 }
769 assert(assigned == true, "should have assigned at least once");
770 return new_sux;
771 }
772
773
774 void BlockBegin::remove_successor(BlockBegin* pred) {
775 int idx;
776 while ((idx = _successors.find(pred)) >= 0) {
777 _successors.remove_at(idx);
778 }
779 }
780
781
782 void BlockBegin::add_predecessor(BlockBegin* pred) {
783 _predecessors.append(pred);
784 }
785
786
787 void BlockBegin::remove_predecessor(BlockBegin* pred) {
788 int idx;
789 while ((idx = _predecessors.find(pred)) >= 0) {
790 _predecessors.remove_at(idx);
791 }
792 }
793
794
795 void BlockBegin::add_exception_handler(BlockBegin* b) {
796 assert(b != NULL && (b->is_set(exception_entry_flag)), "exception handler must exist");
797 // add only if not in the list already
798 if (!_exception_handlers.contains(b)) _exception_handlers.append(b);
799 }
800
801 int BlockBegin::add_exception_state(ValueStack* state) {
802 assert(is_set(exception_entry_flag), "only for xhandlers");
803 if (_exception_states == NULL) {
804 _exception_states = new ValueStackStack(4);
805 }
806 _exception_states->append(state);
807 return _exception_states->length() - 1;
808 }
809
810
811 void BlockBegin::iterate_preorder(boolArray& mark, BlockClosure* closure) {
812 if (!mark.at(block_id())) {
813 mark.at_put(block_id(), true);
814 closure->block_do(this);
815 BlockEnd* e = end(); // must do this after block_do because block_do may change it!
816 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_preorder(mark, closure); }
817 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_preorder(mark, closure); }
818 }
819 }
820
821
822 void BlockBegin::iterate_postorder(boolArray& mark, BlockClosure* closure) {
823 if (!mark.at(block_id())) {
824 mark.at_put(block_id(), true);
825 BlockEnd* e = end();
826 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_postorder(mark, closure); }
827 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_postorder(mark, closure); }
828 closure->block_do(this);
829 }
830 }
831
832
833 void BlockBegin::iterate_preorder(BlockClosure* closure) {
834 int mark_len = number_of_blocks();
835 boolArray mark(mark_len, mark_len, false);
836 iterate_preorder(mark, closure);
837 }
838
839
840 void BlockBegin::iterate_postorder(BlockClosure* closure) {
841 int mark_len = number_of_blocks();
842 boolArray mark(mark_len, mark_len, false);
843 iterate_postorder(mark, closure);
844 }
845
846
847 void BlockBegin::block_values_do(ValueVisitor* f) {
848 for (Instruction* n = this; n != NULL; n = n->next()) n->values_do(f);
849 }
850
851
852 #ifndef PRODUCT
853 #define TRACE_PHI(code) if (PrintPhiFunctions) { code; }
854 #else
855 #define TRACE_PHI(coce)
856 #endif
857
858
859 bool BlockBegin::try_merge(ValueStack* new_state) {
860 TRACE_PHI(tty->print_cr("********** try_merge for block B%d", block_id()));
861
862 // local variables used for state iteration
863 int index;
864 Value new_value, existing_value;
865
866 ValueStack* existing_state = state();
867 if (existing_state == NULL) {
868 TRACE_PHI(tty->print_cr("first call of try_merge for this block"));
869
870 if (is_set(BlockBegin::was_visited_flag)) {
871 // this actually happens for complicated jsr/ret structures
872 return false; // BAILOUT in caller
873 }
874
875 // copy state because it is altered
876 new_state = new_state->copy(ValueStack::BlockBeginState, bci());
877
878 // Use method liveness to invalidate dead locals
879 MethodLivenessResult liveness = new_state->scope()->method()->liveness_at_bci(bci());
880 if (liveness.is_valid()) {
881 assert((int)liveness.size() == new_state->locals_size(), "error in use of liveness");
882
883 for_each_local_value(new_state, index, new_value) {
884 if (!liveness.at(index) || new_value->type()->is_illegal()) {
885 new_state->invalidate_local(index);
886 TRACE_PHI(tty->print_cr("invalidating dead local %d", index));
887 }
888 }
889 }
890
891 if (is_set(BlockBegin::parser_loop_header_flag)) {
892 TRACE_PHI(tty->print_cr("loop header block, initializing phi functions"));
893
894 for_each_stack_value(new_state, index, new_value) {
895 new_state->setup_phi_for_stack(this, index, NULL, new_value);
896 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));
897 }
898
899 BitMap& requires_phi_function = new_state->scope()->requires_phi_function();
900
901 for_each_local_value(new_state, index, new_value) {
902 bool requires_phi = requires_phi_function.at(index) || (new_value->type()->is_double_word() && requires_phi_function.at(index + 1));
903 if (requires_phi || !SelectivePhiFunctions) {
904 new_state->setup_phi_for_local(this, index, NULL, new_value);
905 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));
906 }
907 }
908 }
909
910 // initialize state of block
911 set_state(new_state);
912
913 } else if (existing_state->is_same(new_state)) {
914 TRACE_PHI(tty->print_cr("exisiting state found"));
915
916 assert(existing_state->scope() == new_state->scope(), "not matching");
917 assert(existing_state->locals_size() == new_state->locals_size(), "not matching");
918 assert(existing_state->stack_size() == new_state->stack_size(), "not matching");
919
920 if (is_set(BlockBegin::was_visited_flag)) {
921 TRACE_PHI(tty->print_cr("loop header block, phis must be present"));
922
923 if (!is_set(BlockBegin::parser_loop_header_flag)) {
924 // this actually happens for complicated jsr/ret structures
925 return false; // BAILOUT in caller
926 }
927
928 for_each_local_value(existing_state, index, existing_value) {
929 Value new_value = new_state->local_at(index);
930 if (new_value == NULL || new_value->type()->tag() != existing_value->type()->tag()) {
931 Phi* existing_phi = existing_value->as_Phi();
932 if (existing_phi == NULL) {
933 return false; // BAILOUT in caller
934 }
935 // Invalidate the phi function here. This case is very rare except for
936 // JVMTI capability "can_access_local_variables".
937 // In really rare cases we will bail out in LIRGenerator::move_to_phi.
938 existing_phi->make_illegal();
939 existing_state->invalidate_local(index);
940 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
941 }
942 }
943
944 #ifdef ASSERT
945 // check that all necessary phi functions are present
946 for_each_stack_value(existing_state, index, existing_value) {
947 assert(existing_value->as_Phi() != NULL && existing_value->as_Phi()->block() == this, "phi function required");
948 }
949 for_each_local_value(existing_state, index, existing_value) {
950 assert(existing_value == new_state->local_at(index) || (existing_value->as_Phi() != NULL && existing_value->as_Phi()->as_Phi()->block() == this), "phi function required");
951 }
952 #endif
953
954 } else {
955 TRACE_PHI(tty->print_cr("creating phi functions on demand"));
956
957 // create necessary phi functions for stack
958 for_each_stack_value(existing_state, index, existing_value) {
959 Value new_value = new_state->stack_at(index);
960 Phi* existing_phi = existing_value->as_Phi();
961
962 if (new_value != existing_value && (existing_phi == NULL || existing_phi->block() != this)) {
963 existing_state->setup_phi_for_stack(this, index, existing_value, new_value);
964 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));
965 }
966 }
967
968 // create necessary phi functions for locals
969 for_each_local_value(existing_state, index, existing_value) {
970 Value new_value = new_state->local_at(index);
971 Phi* existing_phi = existing_value->as_Phi();
972
973 if (new_value == NULL || new_value->type()->tag() != existing_value->type()->tag()) {
974 existing_state->invalidate_local(index);
975 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
976 } else if (new_value != existing_value && (existing_phi == NULL || existing_phi->block() != this)) {
977 existing_state->setup_phi_for_local(this, index, existing_value, new_value);
978 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));
979 }
980 }
981 }
982
983 assert(existing_state->caller_state() == new_state->caller_state(), "caller states must be equal");
984
985 } else {
986 assert(false, "stack or locks not matching (invalid bytecodes)");
987 return false;
988 }
989
990 TRACE_PHI(tty->print_cr("********** try_merge for block B%d successful", block_id()));
991
992 return true;
993 }
994
995
996 #ifndef PRODUCT
997 void BlockBegin::print_block() {
998 InstructionPrinter ip;
999 print_block(ip, false);
1000 }
1001
1002
1003 void BlockBegin::print_block(InstructionPrinter& ip, bool live_only) {
1004 ip.print_instr(this); tty->cr();
1005 ip.print_stack(this->state()); tty->cr();
1006 ip.print_inline_level(this);
1007 ip.print_head();
1008 for (Instruction* n = next(); n != NULL; n = n->next()) {
1009 if (!live_only || n->is_pinned() || n->use_count() > 0) {
1010 ip.print_line(n);
1011 }
1012 }
1013 tty->cr();
1014 }
1015 #endif // PRODUCT
1016
1017
1018 // Implementation of BlockList
1019
1020 void BlockList::iterate_forward (BlockClosure* closure) {
1021 const int l = length();
1022 for (int i = 0; i < l; i++) closure->block_do(at(i));
1023 }
1024
1025
1026 void BlockList::iterate_backward(BlockClosure* closure) {
1027 for (int i = length() - 1; i >= 0; i--) closure->block_do(at(i));
1028 }
1029
1030
1031 void BlockList::blocks_do(void f(BlockBegin*)) {
1032 for (int i = length() - 1; i >= 0; i--) f(at(i));
1033 }
1034
1035
1036 void BlockList::values_do(ValueVisitor* f) {
1037 for (int i = length() - 1; i >= 0; i--) at(i)->block_values_do(f);
1038 }
1039
1040
1041 #ifndef PRODUCT
1042 void BlockList::print(bool cfg_only, bool live_only) {
1043 InstructionPrinter ip;
1044 for (int i = 0; i < length(); i++) {
1045 BlockBegin* block = at(i);
1046 if (cfg_only) {
1047 ip.print_instr(block); tty->cr();
1048 } else {
1049 block->print_block(ip, live_only);
1050 }
1051 }
1052 }
1053 #endif // PRODUCT
1054
1055
1056 // Implementation of BlockEnd
1057
1058 void BlockEnd::set_begin(BlockBegin* begin) {
1059 BlockList* sux = NULL;
1060 if (begin != NULL) {
1061 sux = begin->successors();
1062 } else if (this->begin() != NULL) {
1063 // copy our sux list
1064 BlockList* sux = new BlockList(this->begin()->number_of_sux());
1065 for (int i = 0; i < this->begin()->number_of_sux(); i++) {
1066 sux->append(this->begin()->sux_at(i));
1067 }
1068 }
1069 _sux = sux;
1070 }
1071
1072
1073 void BlockEnd::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
1074 substitute(*_sux, old_sux, new_sux);
1075 }
1076
1077
1078 // Implementation of Phi
1079
1080 // Normal phi functions take their operands from the last instruction of the
1081 // predecessor. Special handling is needed for xhanlder entries because there
1082 // the state of arbitrary instructions are needed.
1083
1084 Value Phi::operand_at(int i) const {
1085 ValueStack* state;
1086 if (_block->is_set(BlockBegin::exception_entry_flag)) {
1087 state = _block->exception_state_at(i);
1088 } else {
1089 state = _block->pred_at(i)->end()->state();
1090 }
1091 assert(state != NULL, "");
1092
1093 if (is_local()) {
1094 return state->local_at(local_index());
1095 } else {
1096 return state->stack_at(stack_index());
1097 }
1098 }
1099
1100
1101 int Phi::operand_count() const {
1102 if (_block->is_set(BlockBegin::exception_entry_flag)) {
1103 return _block->number_of_exception_states();
1104 } else {
1105 return _block->number_of_preds();
1106 }
1107 }
1108
1109 #ifdef ASSERT
1110 // Constructor of Assert
1111 Assert::Assert(Value x, Condition cond, bool unordered_is_true, Value y) : Instruction(illegalType)
1112 , _x(x)
1113 , _cond(cond)
1114 , _y(y)
1115 {
1116 set_flag(UnorderedIsTrueFlag, unordered_is_true);
1117 assert(x->type()->tag() == y->type()->tag(), "types must match");
1118 pin();
1119
1120 stringStream strStream;
1121 Compilation::current()->method()->print_name(&strStream);
1122
1123 stringStream strStream1;
1124 InstructionPrinter ip1(1, &strStream1);
1125 ip1.print_instr(x);
1126
1127 stringStream strStream2;
1128 InstructionPrinter ip2(1, &strStream2);
1129 ip2.print_instr(y);
1130
1131 stringStream ss;
1132 ss.print("Assertion %s %s %s in method %s", strStream1.as_string(), ip2.cond_name(cond), strStream2.as_string(), strStream.as_string());
1133
1134 _message = ss.as_string();
1135 }
1136 #endif
1137
1138 void RangeCheckPredicate::check_state() {
1139 assert(state()->kind() != ValueStack::EmptyExceptionState && state()->kind() != ValueStack::ExceptionState, "will deopt with empty state");
1140 }
1141
1142 void ProfileInvoke::state_values_do(ValueVisitor* f) {
1143 if (state() != NULL) state()->values_do(f);
1144 }