1 /*
2 * Copyright (c) 1999, 2017, 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() const {
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()) {
163 // Array covariance (ValueType[] <: Object[])
164 // We will add a runtime check for flat-ness.
165 return true;
166 }
167 }
168 }
169 }
170
171 return false;
172 }
173
174 #ifndef PRODUCT
175 void Instruction::check_state(ValueStack* state) {
176 if (state != NULL) {
177 state->verify();
178 }
179 }
180
181
182 void Instruction::print() {
183 InstructionPrinter ip;
184 print(ip);
185 }
186
187
188 void Instruction::print_line() {
189 InstructionPrinter ip;
190 ip.print_line(this);
191 }
192
193
194 void Instruction::print(InstructionPrinter& ip) {
195 ip.print_head();
196 ip.print_line(this);
197 tty->cr();
198 }
199 #endif // PRODUCT
200
201
202 // perform constant and interval tests on index value
203 bool AccessIndexed::compute_needs_range_check() {
204 if (length()) {
205 Constant* clength = length()->as_Constant();
206 Constant* cindex = index()->as_Constant();
207 if (clength && cindex) {
208 IntConstant* l = clength->type()->as_IntConstant();
209 IntConstant* i = cindex->type()->as_IntConstant();
210 if (l && i && i->value() < l->value() && i->value() >= 0) {
211 return false;
212 }
213 }
214 }
215
216 if (!this->check_flag(NeedsRangeCheckFlag)) {
217 return false;
218 }
219
220 return true;
221 }
222
223
224 ciType* Constant::exact_type() const {
225 if (type()->is_object() && type()->as_ObjectType()->is_loaded()) {
226 return type()->as_ObjectType()->exact_type();
227 }
228 return NULL;
229 }
230
231 ciType* LoadIndexed::exact_type() const {
232 ciType* array_type = array()->exact_type();
233 if (array_type != NULL) {
234 assert(array_type->is_array_klass(), "what else?");
235 ciArrayKlass* ak = (ciArrayKlass*)array_type;
236
237 if (ak->element_type()->is_instance_klass()) {
238 ciInstanceKlass* ik = (ciInstanceKlass*)ak->element_type();
239 if (ik->is_loaded() && ik->is_final()) {
240 return ik;
241 }
242 }
243 }
244 return Instruction::exact_type();
245 }
246
247
248 ciType* LoadIndexed::declared_type() const {
249 ciType* array_type = array()->declared_type();
250 if (array_type == NULL || !array_type->is_loaded()) {
251 return NULL;
252 }
253 assert(array_type->is_array_klass(), "what else?");
254 ciArrayKlass* ak = (ciArrayKlass*)array_type;
255 return ak->element_type();
256 }
257
258
259 ciType* LoadField::declared_type() const {
260 return field()->type();
261 }
262
263
264 ciType* NewTypeArray::exact_type() const {
265 return ciTypeArrayKlass::make(elt_type());
266 }
267
268 ciType* NewObjectArray::exact_type() const {
269 ciKlass* element_klass = klass();
270 if (element_klass->is_valuetype()) {
271 return ciValueArrayKlass::make(element_klass);
272 } else {
273 return ciObjArrayKlass::make(element_klass);
274 }
275 }
276
277 ciType* NewMultiArray::exact_type() const {
278 return _klass;
279 }
280
281 ciType* NewArray::declared_type() const {
282 return exact_type();
283 }
284
285 ciType* NewInstance::exact_type() const {
286 return klass();
287 }
288
289 ciType* NewInstance::declared_type() const {
290 return exact_type();
291 }
292
293 Value NewValueTypeInstance::depends_on() {
294 if (_depends_on != this) {
295 if (_depends_on->as_NewValueTypeInstance() != NULL) {
296 return _depends_on->as_NewValueTypeInstance()->depends_on();
297 }
298 }
299 return _depends_on;
300 }
301
302 ciType* NewValueTypeInstance::exact_type() const {
303 return klass();
304 }
305
306 ciType* NewValueTypeInstance::declared_type() const {
307 return exact_type();
308 }
309
310 ciType* CheckCast::declared_type() const {
311 return klass();
312 }
313
314 // Implementation of ArithmeticOp
315
316 bool ArithmeticOp::is_commutative() const {
317 switch (op()) {
318 case Bytecodes::_iadd: // fall through
319 case Bytecodes::_ladd: // fall through
320 case Bytecodes::_fadd: // fall through
321 case Bytecodes::_dadd: // fall through
322 case Bytecodes::_imul: // fall through
323 case Bytecodes::_lmul: // fall through
324 case Bytecodes::_fmul: // fall through
325 case Bytecodes::_dmul: return true;
326 default : return false;
327 }
328 }
329
330
331 bool ArithmeticOp::can_trap() const {
332 switch (op()) {
333 case Bytecodes::_idiv: // fall through
334 case Bytecodes::_ldiv: // fall through
335 case Bytecodes::_irem: // fall through
336 case Bytecodes::_lrem: return true;
337 default : return false;
338 }
339 }
340
341
342 // Implementation of LogicOp
343
344 bool LogicOp::is_commutative() const {
345 #ifdef ASSERT
346 switch (op()) {
347 case Bytecodes::_iand: // fall through
348 case Bytecodes::_land: // fall through
349 case Bytecodes::_ior : // fall through
350 case Bytecodes::_lor : // fall through
351 case Bytecodes::_ixor: // fall through
352 case Bytecodes::_lxor: break;
353 default : ShouldNotReachHere(); break;
354 }
355 #endif
356 // all LogicOps are commutative
357 return true;
358 }
359
360
361 // Implementation of IfOp
362
363 bool IfOp::is_commutative() const {
364 return cond() == eql || cond() == neq;
365 }
366
367
368 // Implementation of StateSplit
369
370 void StateSplit::substitute(BlockList& list, BlockBegin* old_block, BlockBegin* new_block) {
371 NOT_PRODUCT(bool assigned = false;)
372 for (int i = 0; i < list.length(); i++) {
373 BlockBegin** b = list.adr_at(i);
374 if (*b == old_block) {
375 *b = new_block;
376 NOT_PRODUCT(assigned = true;)
377 }
378 }
379 assert(assigned == true, "should have assigned at least once");
380 }
381
382
383 IRScope* StateSplit::scope() const {
384 return _state->scope();
385 }
386
387
388 void StateSplit::state_values_do(ValueVisitor* f) {
389 Instruction::state_values_do(f);
390 if (state() != NULL) state()->values_do(f);
391 }
392
393
394 void BlockBegin::state_values_do(ValueVisitor* f) {
395 StateSplit::state_values_do(f);
396
397 if (is_set(BlockBegin::exception_entry_flag)) {
398 for (int i = 0; i < number_of_exception_states(); i++) {
399 exception_state_at(i)->values_do(f);
400 }
401 }
402 }
403
404
405 // Implementation of Invoke
406
407
408 Invoke::Invoke(Bytecodes::Code code, ValueType* result_type, Value recv, Values* args,
409 int vtable_index, ciMethod* target, ValueStack* state_before)
410 : StateSplit(result_type, state_before)
411 , _code(code)
412 , _recv(recv)
413 , _args(args)
414 , _vtable_index(vtable_index)
415 , _target(target)
416 {
417 set_flag(TargetIsLoadedFlag, target->is_loaded());
418 set_flag(TargetIsFinalFlag, target_is_loaded() && target->is_final_method());
419 set_flag(TargetIsStrictfpFlag, target_is_loaded() && target->is_strict());
420
421 assert(args != NULL, "args must exist");
422 #ifdef ASSERT
423 AssertValues assert_value;
424 values_do(&assert_value);
425 #endif
426
427 // provide an initial guess of signature size.
428 _signature = new BasicTypeList(number_of_arguments() + (has_receiver() ? 1 : 0));
429 if (has_receiver()) {
430 _signature->append(as_BasicType(receiver()->type()));
431 }
432 for (int i = 0; i < number_of_arguments(); i++) {
433 ValueType* t = argument_at(i)->type();
434 BasicType bt = as_BasicType(t);
435 _signature->append(bt);
436 }
437 }
438
439
440 void Invoke::state_values_do(ValueVisitor* f) {
441 StateSplit::state_values_do(f);
442 if (state_before() != NULL) state_before()->values_do(f);
443 if (state() != NULL) state()->values_do(f);
444 }
445
446 ciType* Invoke::declared_type() const {
447 ciSignature* declared_signature = state()->scope()->method()->get_declared_signature_at_bci(state()->bci());
448 ciType *t = declared_signature->return_type();
449 assert(t->basic_type() != T_VOID, "need return value of void method?");
450 return t;
451 }
452
453 // Implementation of Contant
454 intx Constant::hash() const {
455 if (state_before() == NULL) {
456 switch (type()->tag()) {
457 case intTag:
458 return HASH2(name(), type()->as_IntConstant()->value());
459 case addressTag:
460 return HASH2(name(), type()->as_AddressConstant()->value());
461 case longTag:
462 {
463 jlong temp = type()->as_LongConstant()->value();
464 return HASH3(name(), high(temp), low(temp));
465 }
466 case floatTag:
467 return HASH2(name(), jint_cast(type()->as_FloatConstant()->value()));
468 case doubleTag:
469 {
470 jlong temp = jlong_cast(type()->as_DoubleConstant()->value());
471 return HASH3(name(), high(temp), low(temp));
472 }
473 case objectTag:
474 assert(type()->as_ObjectType()->is_loaded(), "can't handle unloaded values");
475 return HASH2(name(), type()->as_ObjectType()->constant_value());
476 case metaDataTag:
477 assert(type()->as_MetadataType()->is_loaded(), "can't handle unloaded values");
478 return HASH2(name(), type()->as_MetadataType()->constant_value());
479 default:
480 ShouldNotReachHere();
481 }
482 }
483 return 0;
484 }
485
486 bool Constant::is_equal(Value v) const {
487 if (v->as_Constant() == NULL) return false;
488
489 switch (type()->tag()) {
490 case intTag:
491 {
492 IntConstant* t1 = type()->as_IntConstant();
493 IntConstant* t2 = v->type()->as_IntConstant();
494 return (t1 != NULL && t2 != NULL &&
495 t1->value() == t2->value());
496 }
497 case longTag:
498 {
499 LongConstant* t1 = type()->as_LongConstant();
500 LongConstant* t2 = v->type()->as_LongConstant();
501 return (t1 != NULL && t2 != NULL &&
502 t1->value() == t2->value());
503 }
504 case floatTag:
505 {
506 FloatConstant* t1 = type()->as_FloatConstant();
507 FloatConstant* t2 = v->type()->as_FloatConstant();
508 return (t1 != NULL && t2 != NULL &&
509 jint_cast(t1->value()) == jint_cast(t2->value()));
510 }
511 case doubleTag:
512 {
513 DoubleConstant* t1 = type()->as_DoubleConstant();
514 DoubleConstant* t2 = v->type()->as_DoubleConstant();
515 return (t1 != NULL && t2 != NULL &&
516 jlong_cast(t1->value()) == jlong_cast(t2->value()));
517 }
518 case objectTag:
519 {
520 ObjectType* t1 = type()->as_ObjectType();
521 ObjectType* t2 = v->type()->as_ObjectType();
522 return (t1 != NULL && t2 != NULL &&
523 t1->is_loaded() && t2->is_loaded() &&
524 t1->constant_value() == t2->constant_value());
525 }
526 case metaDataTag:
527 {
528 MetadataType* t1 = type()->as_MetadataType();
529 MetadataType* t2 = v->type()->as_MetadataType();
530 return (t1 != NULL && t2 != NULL &&
531 t1->is_loaded() && t2->is_loaded() &&
532 t1->constant_value() == t2->constant_value());
533 }
534 default:
535 return false;
536 }
537 }
538
539 Constant::CompareResult Constant::compare(Instruction::Condition cond, Value right) const {
540 Constant* rc = right->as_Constant();
541 // other is not a constant
542 if (rc == NULL) return not_comparable;
543
544 ValueType* lt = type();
545 ValueType* rt = rc->type();
546 // different types
547 if (lt->base() != rt->base()) return not_comparable;
548 switch (lt->tag()) {
549 case intTag: {
550 int x = lt->as_IntConstant()->value();
551 int y = rt->as_IntConstant()->value();
552 switch (cond) {
553 case If::eql: return x == y ? cond_true : cond_false;
554 case If::neq: return x != y ? cond_true : cond_false;
555 case If::lss: return x < y ? cond_true : cond_false;
556 case If::leq: return x <= y ? cond_true : cond_false;
557 case If::gtr: return x > y ? cond_true : cond_false;
558 case If::geq: return x >= y ? cond_true : cond_false;
559 default : break;
560 }
561 break;
562 }
563 case longTag: {
564 jlong x = lt->as_LongConstant()->value();
565 jlong y = rt->as_LongConstant()->value();
566 switch (cond) {
567 case If::eql: return x == y ? cond_true : cond_false;
568 case If::neq: return x != y ? cond_true : cond_false;
569 case If::lss: return x < y ? cond_true : cond_false;
570 case If::leq: return x <= y ? cond_true : cond_false;
571 case If::gtr: return x > y ? cond_true : cond_false;
572 case If::geq: return x >= y ? cond_true : cond_false;
573 default : break;
574 }
575 break;
576 }
577 case objectTag: {
578 ciObject* xvalue = lt->as_ObjectType()->constant_value();
579 ciObject* yvalue = rt->as_ObjectType()->constant_value();
580 assert(xvalue != NULL && yvalue != NULL, "not constants");
581 if (xvalue->is_loaded() && yvalue->is_loaded()) {
582 switch (cond) {
583 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
584 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
585 default : break;
586 }
587 }
588 break;
589 }
590 case metaDataTag: {
591 ciMetadata* xvalue = lt->as_MetadataType()->constant_value();
592 ciMetadata* yvalue = rt->as_MetadataType()->constant_value();
593 assert(xvalue != NULL && yvalue != NULL, "not constants");
594 if (xvalue->is_loaded() && yvalue->is_loaded()) {
595 switch (cond) {
596 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
597 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
598 default : break;
599 }
600 }
601 break;
602 }
603 default:
604 break;
605 }
606 return not_comparable;
607 }
608
609
610 // Implementation of BlockBegin
611
612 void BlockBegin::set_end(BlockEnd* end) {
613 assert(end != NULL, "should not reset block end to NULL");
614 if (end == _end) {
615 return;
616 }
617 clear_end();
618
619 // Set the new end
620 _end = end;
621
622 _successors.clear();
623 // Now reset successors list based on BlockEnd
624 for (int i = 0; i < end->number_of_sux(); i++) {
625 BlockBegin* sux = end->sux_at(i);
626 _successors.append(sux);
627 sux->_predecessors.append(this);
628 }
629 _end->set_begin(this);
630 }
631
632
633 void BlockBegin::clear_end() {
634 // Must make the predecessors/successors match up with the
635 // BlockEnd's notion.
636 if (_end != NULL) {
637 // disconnect from the old end
638 _end->set_begin(NULL);
639
640 // disconnect this block from it's current successors
641 for (int i = 0; i < _successors.length(); i++) {
642 _successors.at(i)->remove_predecessor(this);
643 }
644 _end = NULL;
645 }
646 }
647
648
649 void BlockBegin::disconnect_edge(BlockBegin* from, BlockBegin* to) {
650 // disconnect any edges between from and to
651 #ifndef PRODUCT
652 if (PrintIR && Verbose) {
653 tty->print_cr("Disconnected edge B%d -> B%d", from->block_id(), to->block_id());
654 }
655 #endif
656 for (int s = 0; s < from->number_of_sux();) {
657 BlockBegin* sux = from->sux_at(s);
658 if (sux == to) {
659 int index = sux->_predecessors.find(from);
660 if (index >= 0) {
661 sux->_predecessors.remove_at(index);
662 }
663 from->_successors.remove_at(s);
664 } else {
665 s++;
666 }
667 }
668 }
669
670
671 void BlockBegin::disconnect_from_graph() {
672 // disconnect this block from all other blocks
673 for (int p = 0; p < number_of_preds(); p++) {
674 pred_at(p)->remove_successor(this);
675 }
676 for (int s = 0; s < number_of_sux(); s++) {
677 sux_at(s)->remove_predecessor(this);
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 int bci = sux->bci();
702 // critical edge splitting may introduce a goto after a if and array
703 // bound check elimination may insert a predicate between the if and
704 // goto. The bci of the goto can't be the one of the if otherwise
705 // the state and bci are inconsistent and a deoptimization triggered
706 // by the predicate would lead to incorrect execution/a crash.
707 BlockBegin* new_sux = new BlockBegin(bci);
708
709 // mark this block (special treatment when block order is computed)
710 new_sux->set(critical_edge_split_flag);
711
712 // This goto is not a safepoint.
713 Goto* e = new Goto(sux, false);
714 new_sux->set_next(e, bci);
715 new_sux->set_end(e);
716 // setup states
717 ValueStack* s = end()->state();
718 new_sux->set_state(s->copy(s->kind(), bci));
719 e->set_state(s->copy(s->kind(), bci));
720 assert(new_sux->state()->locals_size() == s->locals_size(), "local size mismatch!");
721 assert(new_sux->state()->stack_size() == s->stack_size(), "stack size mismatch!");
722 assert(new_sux->state()->locks_size() == s->locks_size(), "locks size mismatch!");
723
724 // link predecessor to new block
725 end()->substitute_sux(sux, new_sux);
726
727 // The ordering needs to be the same, so remove the link that the
728 // set_end call above added and substitute the new_sux for this
729 // block.
730 sux->remove_predecessor(new_sux);
731
732 // the successor could be the target of a switch so it might have
733 // multiple copies of this predecessor, so substitute the new_sux
734 // for the first and delete the rest.
735 bool assigned = false;
736 BlockList& list = sux->_predecessors;
737 for (int i = 0; i < list.length(); i++) {
738 BlockBegin** b = list.adr_at(i);
739 if (*b == this) {
740 if (assigned) {
741 list.remove_at(i);
742 // reprocess this index
743 i--;
744 } else {
745 assigned = true;
746 *b = new_sux;
747 }
748 // link the new block back to it's predecessors.
749 new_sux->add_predecessor(this);
750 }
751 }
752 assert(assigned == true, "should have assigned at least once");
753 return new_sux;
754 }
755
756
757 void BlockBegin::remove_successor(BlockBegin* pred) {
758 int idx;
759 while ((idx = _successors.find(pred)) >= 0) {
760 _successors.remove_at(idx);
761 }
762 }
763
764
765 void BlockBegin::add_predecessor(BlockBegin* pred) {
766 _predecessors.append(pred);
767 }
768
769
770 void BlockBegin::remove_predecessor(BlockBegin* pred) {
771 int idx;
772 while ((idx = _predecessors.find(pred)) >= 0) {
773 _predecessors.remove_at(idx);
774 }
775 }
776
777
778 void BlockBegin::add_exception_handler(BlockBegin* b) {
779 assert(b != NULL && (b->is_set(exception_entry_flag)), "exception handler must exist");
780 // add only if not in the list already
781 if (!_exception_handlers.contains(b)) _exception_handlers.append(b);
782 }
783
784 int BlockBegin::add_exception_state(ValueStack* state) {
785 assert(is_set(exception_entry_flag), "only for xhandlers");
786 if (_exception_states == NULL) {
787 _exception_states = new ValueStackStack(4);
788 }
789 _exception_states->append(state);
790 return _exception_states->length() - 1;
791 }
792
793
794 void BlockBegin::iterate_preorder(boolArray& mark, BlockClosure* closure) {
795 if (!mark.at(block_id())) {
796 mark.at_put(block_id(), true);
797 closure->block_do(this);
798 BlockEnd* e = end(); // must do this after block_do because block_do may change it!
799 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_preorder(mark, closure); }
800 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_preorder(mark, closure); }
801 }
802 }
803
804
805 void BlockBegin::iterate_postorder(boolArray& mark, BlockClosure* closure) {
806 if (!mark.at(block_id())) {
807 mark.at_put(block_id(), true);
808 BlockEnd* e = end();
809 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_postorder(mark, closure); }
810 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_postorder(mark, closure); }
811 closure->block_do(this);
812 }
813 }
814
815
816 void BlockBegin::iterate_preorder(BlockClosure* closure) {
817 int mark_len = number_of_blocks();
818 boolArray mark(mark_len, mark_len, false);
819 iterate_preorder(mark, closure);
820 }
821
822
823 void BlockBegin::iterate_postorder(BlockClosure* closure) {
824 int mark_len = number_of_blocks();
825 boolArray mark(mark_len, mark_len, false);
826 iterate_postorder(mark, closure);
827 }
828
829
830 void BlockBegin::block_values_do(ValueVisitor* f) {
831 for (Instruction* n = this; n != NULL; n = n->next()) n->values_do(f);
832 }
833
834
835 #ifndef PRODUCT
836 #define TRACE_PHI(code) if (PrintPhiFunctions) { code; }
837 #else
838 #define TRACE_PHI(coce)
839 #endif
840
841
842 bool BlockBegin::try_merge(ValueStack* new_state) {
843 TRACE_PHI(tty->print_cr("********** try_merge for block B%d", block_id()));
844
845 // local variables used for state iteration
846 int index;
847 Value new_value, existing_value;
848
849 ValueStack* existing_state = state();
850 if (existing_state == NULL) {
851 TRACE_PHI(tty->print_cr("first call of try_merge for this block"));
852
853 if (is_set(BlockBegin::was_visited_flag)) {
854 // this actually happens for complicated jsr/ret structures
855 return false; // BAILOUT in caller
856 }
857
858 // copy state because it is altered
859 new_state = new_state->copy(ValueStack::BlockBeginState, bci());
860
861 // Use method liveness to invalidate dead locals
862 MethodLivenessResult liveness = new_state->scope()->method()->liveness_at_bci(bci());
863 if (liveness.is_valid()) {
864 assert((int)liveness.size() == new_state->locals_size(), "error in use of liveness");
865
866 for_each_local_value(new_state, index, new_value) {
867 if (!liveness.at(index) || new_value->type()->is_illegal()) {
868 new_state->invalidate_local(index);
869 TRACE_PHI(tty->print_cr("invalidating dead local %d", index));
870 }
871 }
872 }
873
874 if (is_set(BlockBegin::parser_loop_header_flag)) {
875 TRACE_PHI(tty->print_cr("loop header block, initializing phi functions"));
876
877 for_each_stack_value(new_state, index, new_value) {
878 new_state->setup_phi_for_stack(this, index, NULL, new_value);
879 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));
880 }
881
882 BitMap& requires_phi_function = new_state->scope()->requires_phi_function();
883
884 for_each_local_value(new_state, index, new_value) {
885 bool requires_phi = requires_phi_function.at(index) || (new_value->type()->is_double_word() && requires_phi_function.at(index + 1));
886 if (requires_phi || !SelectivePhiFunctions) {
887 new_state->setup_phi_for_local(this, index, NULL, new_value);
888 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));
889 }
890 }
891 }
892
893 // initialize state of block
894 set_state(new_state);
895
896 } else if (existing_state->is_same(new_state)) {
897 TRACE_PHI(tty->print_cr("exisiting state found"));
898
899 assert(existing_state->scope() == new_state->scope(), "not matching");
900 assert(existing_state->locals_size() == new_state->locals_size(), "not matching");
901 assert(existing_state->stack_size() == new_state->stack_size(), "not matching");
902
903 if (is_set(BlockBegin::was_visited_flag)) {
904 TRACE_PHI(tty->print_cr("loop header block, phis must be present"));
905
906 if (!is_set(BlockBegin::parser_loop_header_flag)) {
907 // this actually happens for complicated jsr/ret structures
908 return false; // BAILOUT in caller
909 }
910
911 for_each_local_value(existing_state, index, existing_value) {
912 Value new_value = new_state->local_at(index);
913 if (new_value == NULL || new_value->type()->tag() != existing_value->type()->tag()) {
914 Phi* existing_phi = existing_value->as_Phi();
915 if (existing_phi == NULL) {
916 return false; // BAILOUT in caller
917 }
918 // Invalidate the phi function here. This case is very rare except for
919 // JVMTI capability "can_access_local_variables".
920 // In really rare cases we will bail out in LIRGenerator::move_to_phi.
921 existing_phi->make_illegal();
922 existing_state->invalidate_local(index);
923 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
924 }
925 }
926
927 #ifdef ASSERT
928 // check that all necessary phi functions are present
929 for_each_stack_value(existing_state, index, existing_value) {
930 assert(existing_value->as_Phi() != NULL && existing_value->as_Phi()->block() == this, "phi function required");
931 }
932 for_each_local_value(existing_state, index, existing_value) {
933 assert(existing_value == new_state->local_at(index) || (existing_value->as_Phi() != NULL && existing_value->as_Phi()->as_Phi()->block() == this), "phi function required");
934 }
935 #endif
936
937 } else {
938 TRACE_PHI(tty->print_cr("creating phi functions on demand"));
939
940 // create necessary phi functions for stack
941 for_each_stack_value(existing_state, index, existing_value) {
942 Value new_value = new_state->stack_at(index);
943 Phi* existing_phi = existing_value->as_Phi();
944
945 if (new_value != existing_value && (existing_phi == NULL || existing_phi->block() != this)) {
946 existing_state->setup_phi_for_stack(this, index, existing_value, new_value);
947 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));
948 }
949 }
950
951 // create necessary phi functions for locals
952 for_each_local_value(existing_state, index, existing_value) {
953 Value new_value = new_state->local_at(index);
954 Phi* existing_phi = existing_value->as_Phi();
955
956 if (new_value == NULL || new_value->type()->tag() != existing_value->type()->tag()) {
957 existing_state->invalidate_local(index);
958 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
959 } else if (new_value != existing_value && (existing_phi == NULL || existing_phi->block() != this)) {
960 existing_state->setup_phi_for_local(this, index, existing_value, new_value);
961 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));
962 }
963 }
964 }
965
966 assert(existing_state->caller_state() == new_state->caller_state(), "caller states must be equal");
967
968 } else {
969 assert(false, "stack or locks not matching (invalid bytecodes)");
970 return false;
971 }
972
973 TRACE_PHI(tty->print_cr("********** try_merge for block B%d successful", block_id()));
974
975 return true;
976 }
977
978
979 #ifndef PRODUCT
980 void BlockBegin::print_block() {
981 InstructionPrinter ip;
982 print_block(ip, false);
983 }
984
985
986 void BlockBegin::print_block(InstructionPrinter& ip, bool live_only) {
987 ip.print_instr(this); tty->cr();
988 ip.print_stack(this->state()); tty->cr();
989 ip.print_inline_level(this);
990 ip.print_head();
991 for (Instruction* n = next(); n != NULL; n = n->next()) {
992 if (!live_only || n->is_pinned() || n->use_count() > 0) {
993 ip.print_line(n);
994 }
995 }
996 tty->cr();
997 }
998 #endif // PRODUCT
999
1000
1001 // Implementation of BlockList
1002
1003 void BlockList::iterate_forward (BlockClosure* closure) {
1004 const int l = length();
1005 for (int i = 0; i < l; i++) closure->block_do(at(i));
1006 }
1007
1008
1009 void BlockList::iterate_backward(BlockClosure* closure) {
1010 for (int i = length() - 1; i >= 0; i--) closure->block_do(at(i));
1011 }
1012
1013
1014 void BlockList::blocks_do(void f(BlockBegin*)) {
1015 for (int i = length() - 1; i >= 0; i--) f(at(i));
1016 }
1017
1018
1019 void BlockList::values_do(ValueVisitor* f) {
1020 for (int i = length() - 1; i >= 0; i--) at(i)->block_values_do(f);
1021 }
1022
1023
1024 #ifndef PRODUCT
1025 void BlockList::print(bool cfg_only, bool live_only) {
1026 InstructionPrinter ip;
1027 for (int i = 0; i < length(); i++) {
1028 BlockBegin* block = at(i);
1029 if (cfg_only) {
1030 ip.print_instr(block); tty->cr();
1031 } else {
1032 block->print_block(ip, live_only);
1033 }
1034 }
1035 }
1036 #endif // PRODUCT
1037
1038
1039 // Implementation of BlockEnd
1040
1041 void BlockEnd::set_begin(BlockBegin* begin) {
1042 BlockList* sux = NULL;
1043 if (begin != NULL) {
1044 sux = begin->successors();
1045 } else if (this->begin() != NULL) {
1046 // copy our sux list
1047 BlockList* sux = new BlockList(this->begin()->number_of_sux());
1048 for (int i = 0; i < this->begin()->number_of_sux(); i++) {
1049 sux->append(this->begin()->sux_at(i));
1050 }
1051 }
1052 _sux = sux;
1053 }
1054
1055
1056 void BlockEnd::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
1057 substitute(*_sux, old_sux, new_sux);
1058 }
1059
1060
1061 // Implementation of Phi
1062
1063 // Normal phi functions take their operands from the last instruction of the
1064 // predecessor. Special handling is needed for xhanlder entries because there
1065 // the state of arbitrary instructions are needed.
1066
1067 Value Phi::operand_at(int i) const {
1068 ValueStack* state;
1069 if (_block->is_set(BlockBegin::exception_entry_flag)) {
1070 state = _block->exception_state_at(i);
1071 } else {
1072 state = _block->pred_at(i)->end()->state();
1073 }
1074 assert(state != NULL, "");
1075
1076 if (is_local()) {
1077 return state->local_at(local_index());
1078 } else {
1079 return state->stack_at(stack_index());
1080 }
1081 }
1082
1083
1084 int Phi::operand_count() const {
1085 if (_block->is_set(BlockBegin::exception_entry_flag)) {
1086 return _block->number_of_exception_states();
1087 } else {
1088 return _block->number_of_preds();
1089 }
1090 }
1091
1092 #ifdef ASSERT
1093 // Constructor of Assert
1094 Assert::Assert(Value x, Condition cond, bool unordered_is_true, Value y) : Instruction(illegalType)
1095 , _x(x)
1096 , _cond(cond)
1097 , _y(y)
1098 {
1099 set_flag(UnorderedIsTrueFlag, unordered_is_true);
1100 assert(x->type()->tag() == y->type()->tag(), "types must match");
1101 pin();
1102
1103 stringStream strStream;
1104 Compilation::current()->method()->print_name(&strStream);
1105
1106 stringStream strStream1;
1107 InstructionPrinter ip1(1, &strStream1);
1108 ip1.print_instr(x);
1109
1110 stringStream strStream2;
1111 InstructionPrinter ip2(1, &strStream2);
1112 ip2.print_instr(y);
1113
1114 stringStream ss;
1115 ss.print("Assertion %s %s %s in method %s", strStream1.as_string(), ip2.cond_name(cond), strStream2.as_string(), strStream.as_string());
1116
1117 _message = ss.as_string();
1118 }
1119 #endif
1120
1121 void RangeCheckPredicate::check_state() {
1122 assert(state()->kind() != ValueStack::EmptyExceptionState && state()->kind() != ValueStack::ExceptionState, "will deopt with empty state");
1123 }
1124
1125 void ProfileInvoke::state_values_do(ValueVisitor* f) {
1126 if (state() != NULL) state()->values_do(f);
1127 }