1 /*
2 * Copyright (c) 1999, 2010, 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 "incls/_precompiled.incl"
26 #include "incls/_c1_Instruction.cpp.incl"
27
28
29 // Implementation of Instruction
30
31
32 #ifdef ASSERT
33 void Instruction::create_hi_word() {
34 assert(type()->is_double_word() && _hi_word == NULL, "only double word has high word");
35 _hi_word = new HiWord(this);
36 }
37 #endif
38
39 Instruction::Condition Instruction::mirror(Condition cond) {
40 switch (cond) {
41 case eql: return eql;
42 case neq: return neq;
43 case lss: return gtr;
44 case leq: return geq;
45 case gtr: return lss;
46 case geq: return leq;
47 }
48 ShouldNotReachHere();
49 return eql;
50 }
51
52
53 Instruction::Condition Instruction::negate(Condition cond) {
54 switch (cond) {
55 case eql: return neq;
56 case neq: return eql;
57 case lss: return geq;
58 case leq: return gtr;
59 case gtr: return leq;
60 case geq: return lss;
61 }
62 ShouldNotReachHere();
63 return eql;
64 }
65
66
67 Instruction* Instruction::prev(BlockBegin* block) {
68 Instruction* p = NULL;
69 Instruction* q = block;
70 while (q != this) {
71 assert(q != NULL, "this is not in the block's instruction list");
72 p = q; q = q->next();
73 }
74 return p;
75 }
76
77
78 #ifndef PRODUCT
79 void Instruction::print() {
80 InstructionPrinter ip;
81 print(ip);
82 }
83
84
85 void Instruction::print_line() {
86 InstructionPrinter ip;
87 ip.print_line(this);
88 }
89
90
91 void Instruction::print(InstructionPrinter& ip) {
92 ip.print_head();
93 ip.print_line(this);
94 tty->cr();
95 }
96 #endif // PRODUCT
97
98
99 // perform constant and interval tests on index value
100 bool AccessIndexed::compute_needs_range_check() {
101 Constant* clength = length()->as_Constant();
102 Constant* cindex = index()->as_Constant();
103 if (clength && cindex) {
104 IntConstant* l = clength->type()->as_IntConstant();
105 IntConstant* i = cindex->type()->as_IntConstant();
106 if (l && i && i->value() < l->value() && i->value() >= 0) {
107 return false;
108 }
109 }
110 return true;
111 }
112
113
114 ciType* LoadIndexed::exact_type() const {
115 ciType* array_type = array()->exact_type();
116 if (array_type == NULL) {
117 return NULL;
118 }
119 assert(array_type->is_array_klass(), "what else?");
120 ciArrayKlass* ak = (ciArrayKlass*)array_type;
121
122 if (ak->element_type()->is_instance_klass()) {
123 ciInstanceKlass* ik = (ciInstanceKlass*)ak->element_type();
124 if (ik->is_loaded() && ik->is_final()) {
125 return ik;
126 }
127 }
128 return NULL;
129 }
130
131
132 ciType* LoadIndexed::declared_type() const {
133 ciType* array_type = array()->declared_type();
134 if (array_type == NULL) {
135 return NULL;
136 }
137 assert(array_type->is_array_klass(), "what else?");
138 ciArrayKlass* ak = (ciArrayKlass*)array_type;
139 return ak->element_type();
140 }
141
142
143 ciType* LoadField::declared_type() const {
144 return field()->type();
145 }
146
147
148 ciType* LoadField::exact_type() const {
149 ciType* type = declared_type();
150 // for primitive arrays, the declared type is the exact type
151 if (type->is_type_array_klass()) {
152 return type;
153 }
154 if (type->is_instance_klass()) {
155 ciInstanceKlass* ik = (ciInstanceKlass*)type;
156 if (ik->is_loaded() && ik->is_final()) {
157 return type;
158 }
159 }
160 return NULL;
161 }
162
163
164 ciType* NewTypeArray::exact_type() const {
165 return ciTypeArrayKlass::make(elt_type());
166 }
167
168
169 ciType* NewObjectArray::exact_type() const {
170 return ciObjArrayKlass::make(klass());
171 }
172
173
174 ciType* NewInstance::exact_type() const {
175 return klass();
176 }
177
178
179 ciType* CheckCast::declared_type() const {
180 return klass();
181 }
182
183 ciType* CheckCast::exact_type() const {
184 if (klass()->is_instance_klass()) {
185 ciInstanceKlass* ik = (ciInstanceKlass*)klass();
186 if (ik->is_loaded() && ik->is_final()) {
187 return ik;
188 }
189 }
190 return NULL;
191 }
192
193
194 void ArithmeticOp::other_values_do(ValueVisitor* f) {
195 if (lock_stack() != NULL) lock_stack()->values_do(f);
196 }
197
198 void NullCheck::other_values_do(ValueVisitor* f) {
199 lock_stack()->values_do(f);
200 }
201
202 void AccessArray::other_values_do(ValueVisitor* f) {
203 if (lock_stack() != NULL) lock_stack()->values_do(f);
204 }
205
206
207 // Implementation of AccessField
208
209 void AccessField::other_values_do(ValueVisitor* f) {
210 if (state_before() != NULL) state_before()->values_do(f);
211 if (lock_stack() != NULL) lock_stack()->values_do(f);
212 }
213
214
215 // Implementation of StoreIndexed
216
217 IRScope* StoreIndexed::scope() const {
218 return lock_stack()->scope();
219 }
220
221
222 // Implementation of ArithmeticOp
223
224 bool ArithmeticOp::is_commutative() const {
225 switch (op()) {
226 case Bytecodes::_iadd: // fall through
227 case Bytecodes::_ladd: // fall through
228 case Bytecodes::_fadd: // fall through
229 case Bytecodes::_dadd: // fall through
230 case Bytecodes::_imul: // fall through
231 case Bytecodes::_lmul: // fall through
232 case Bytecodes::_fmul: // fall through
233 case Bytecodes::_dmul: return true;
234 }
235 return false;
236 }
237
238
239 bool ArithmeticOp::can_trap() const {
240 switch (op()) {
241 case Bytecodes::_idiv: // fall through
242 case Bytecodes::_ldiv: // fall through
243 case Bytecodes::_irem: // fall through
244 case Bytecodes::_lrem: return true;
245 }
246 return false;
247 }
248
249
250 // Implementation of LogicOp
251
252 bool LogicOp::is_commutative() const {
253 #ifdef ASSERT
254 switch (op()) {
255 case Bytecodes::_iand: // fall through
256 case Bytecodes::_land: // fall through
257 case Bytecodes::_ior : // fall through
258 case Bytecodes::_lor : // fall through
259 case Bytecodes::_ixor: // fall through
260 case Bytecodes::_lxor: break;
261 default : ShouldNotReachHere();
262 }
263 #endif
264 // all LogicOps are commutative
265 return true;
266 }
267
268
269 // Implementation of CompareOp
270
271 void CompareOp::other_values_do(ValueVisitor* f) {
272 if (state_before() != NULL) state_before()->values_do(f);
273 }
274
275
276 // Implementation of IfOp
277
278 bool IfOp::is_commutative() const {
279 return cond() == eql || cond() == neq;
280 }
281
282
283 // Implementation of StateSplit
284
285 void StateSplit::substitute(BlockList& list, BlockBegin* old_block, BlockBegin* new_block) {
286 NOT_PRODUCT(bool assigned = false;)
287 for (int i = 0; i < list.length(); i++) {
288 BlockBegin** b = list.adr_at(i);
289 if (*b == old_block) {
290 *b = new_block;
291 NOT_PRODUCT(assigned = true;)
292 }
293 }
294 assert(assigned == true, "should have assigned at least once");
295 }
296
297
298 IRScope* StateSplit::scope() const {
299 return _state->scope();
300 }
301
302
303 void StateSplit::state_values_do(ValueVisitor* f) {
304 if (state() != NULL) state()->values_do(f);
305 }
306
307
308 void BlockBegin::state_values_do(ValueVisitor* f) {
309 StateSplit::state_values_do(f);
310
311 if (is_set(BlockBegin::exception_entry_flag)) {
312 for (int i = 0; i < number_of_exception_states(); i++) {
313 exception_state_at(i)->values_do(f);
314 }
315 }
316 }
317
318
319 void MonitorEnter::state_values_do(ValueVisitor* f) {
320 StateSplit::state_values_do(f);
321 _lock_stack_before->values_do(f);
322 }
323
324
325 void Intrinsic::state_values_do(ValueVisitor* f) {
326 StateSplit::state_values_do(f);
327 if (lock_stack() != NULL) lock_stack()->values_do(f);
328 }
329
330
331 // Implementation of Invoke
332
333
334 Invoke::Invoke(Bytecodes::Code code, ValueType* result_type, Value recv, Values* args,
335 int vtable_index, ciMethod* target, ValueStack* state_before)
336 : StateSplit(result_type)
337 , _code(code)
338 , _recv(recv)
339 , _args(args)
340 , _vtable_index(vtable_index)
341 , _target(target)
342 , _state_before(state_before)
343 {
344 set_flag(TargetIsLoadedFlag, target->is_loaded());
345 set_flag(TargetIsFinalFlag, target_is_loaded() && target->is_final_method());
346 set_flag(TargetIsStrictfpFlag, target_is_loaded() && target->is_strict());
347
348 assert(args != NULL, "args must exist");
349 #ifdef ASSERT
350 AssertValues assert_value;
351 values_do(&assert_value);
352 #endif
353
354 // provide an initial guess of signature size.
355 _signature = new BasicTypeList(number_of_arguments() + (has_receiver() ? 1 : 0));
356 if (has_receiver()) {
357 _signature->append(as_BasicType(receiver()->type()));
358 } else if (is_invokedynamic()) {
359 // Add the synthetic MethodHandle argument to the signature.
360 _signature->append(T_OBJECT);
361 }
362 for (int i = 0; i < number_of_arguments(); i++) {
363 ValueType* t = argument_at(i)->type();
364 BasicType bt = as_BasicType(t);
365 _signature->append(bt);
366 }
367 }
368
369
370 void Invoke::state_values_do(ValueVisitor* f) {
371 StateSplit::state_values_do(f);
372 if (state_before() != NULL) state_before()->values_do(f);
373 if (state() != NULL) state()->values_do(f);
374 }
375
376
377 // Implementation of Contant
378 intx Constant::hash() const {
379 if (_state == NULL) {
380 switch (type()->tag()) {
381 case intTag:
382 return HASH2(name(), type()->as_IntConstant()->value());
383 case longTag:
384 {
385 jlong temp = type()->as_LongConstant()->value();
386 return HASH3(name(), high(temp), low(temp));
387 }
388 case floatTag:
389 return HASH2(name(), jint_cast(type()->as_FloatConstant()->value()));
390 case doubleTag:
391 {
392 jlong temp = jlong_cast(type()->as_DoubleConstant()->value());
393 return HASH3(name(), high(temp), low(temp));
394 }
395 case objectTag:
396 assert(type()->as_ObjectType()->is_loaded(), "can't handle unloaded values");
397 return HASH2(name(), type()->as_ObjectType()->constant_value());
398 }
399 }
400 return 0;
401 }
402
403 bool Constant::is_equal(Value v) const {
404 if (v->as_Constant() == NULL) return false;
405
406 switch (type()->tag()) {
407 case intTag:
408 {
409 IntConstant* t1 = type()->as_IntConstant();
410 IntConstant* t2 = v->type()->as_IntConstant();
411 return (t1 != NULL && t2 != NULL &&
412 t1->value() == t2->value());
413 }
414 case longTag:
415 {
416 LongConstant* t1 = type()->as_LongConstant();
417 LongConstant* t2 = v->type()->as_LongConstant();
418 return (t1 != NULL && t2 != NULL &&
419 t1->value() == t2->value());
420 }
421 case floatTag:
422 {
423 FloatConstant* t1 = type()->as_FloatConstant();
424 FloatConstant* t2 = v->type()->as_FloatConstant();
425 return (t1 != NULL && t2 != NULL &&
426 jint_cast(t1->value()) == jint_cast(t2->value()));
427 }
428 case doubleTag:
429 {
430 DoubleConstant* t1 = type()->as_DoubleConstant();
431 DoubleConstant* t2 = v->type()->as_DoubleConstant();
432 return (t1 != NULL && t2 != NULL &&
433 jlong_cast(t1->value()) == jlong_cast(t2->value()));
434 }
435 case objectTag:
436 {
437 ObjectType* t1 = type()->as_ObjectType();
438 ObjectType* t2 = v->type()->as_ObjectType();
439 return (t1 != NULL && t2 != NULL &&
440 t1->is_loaded() && t2->is_loaded() &&
441 t1->constant_value() == t2->constant_value());
442 }
443 }
444 return false;
445 }
446
447
448 BlockBegin* Constant::compare(Instruction::Condition cond, Value right,
449 BlockBegin* true_sux, BlockBegin* false_sux) {
450 Constant* rc = right->as_Constant();
451 // other is not a constant
452 if (rc == NULL) return NULL;
453
454 ValueType* lt = type();
455 ValueType* rt = rc->type();
456 // different types
457 if (lt->base() != rt->base()) return NULL;
458 switch (lt->tag()) {
459 case intTag: {
460 int x = lt->as_IntConstant()->value();
461 int y = rt->as_IntConstant()->value();
462 switch (cond) {
463 case If::eql: return x == y ? true_sux : false_sux;
464 case If::neq: return x != y ? true_sux : false_sux;
465 case If::lss: return x < y ? true_sux : false_sux;
466 case If::leq: return x <= y ? true_sux : false_sux;
467 case If::gtr: return x > y ? true_sux : false_sux;
468 case If::geq: return x >= y ? true_sux : false_sux;
469 }
470 break;
471 }
472 case longTag: {
473 jlong x = lt->as_LongConstant()->value();
474 jlong y = rt->as_LongConstant()->value();
475 switch (cond) {
476 case If::eql: return x == y ? true_sux : false_sux;
477 case If::neq: return x != y ? true_sux : false_sux;
478 case If::lss: return x < y ? true_sux : false_sux;
479 case If::leq: return x <= y ? true_sux : false_sux;
480 case If::gtr: return x > y ? true_sux : false_sux;
481 case If::geq: return x >= y ? true_sux : false_sux;
482 }
483 break;
484 }
485 case objectTag: {
486 ciObject* xvalue = lt->as_ObjectType()->constant_value();
487 ciObject* yvalue = rt->as_ObjectType()->constant_value();
488 assert(xvalue != NULL && yvalue != NULL, "not constants");
489 if (xvalue->is_loaded() && yvalue->is_loaded()) {
490 switch (cond) {
491 case If::eql: return xvalue == yvalue ? true_sux : false_sux;
492 case If::neq: return xvalue != yvalue ? true_sux : false_sux;
493 }
494 }
495 break;
496 }
497 }
498 return NULL;
499 }
500
501
502 void Constant::other_values_do(ValueVisitor* f) {
503 if (state() != NULL) state()->values_do(f);
504 }
505
506
507 // Implementation of NewArray
508
509 void NewArray::other_values_do(ValueVisitor* f) {
510 if (state_before() != NULL) state_before()->values_do(f);
511 }
512
513
514 // Implementation of TypeCheck
515
516 void TypeCheck::other_values_do(ValueVisitor* f) {
517 if (state_before() != NULL) state_before()->values_do(f);
518 }
519
520
521 // Implementation of BlockBegin
522
523 void BlockBegin::set_end(BlockEnd* end) {
524 assert(end != NULL, "should not reset block end to NULL");
525 BlockEnd* old_end = _end;
526 if (end == old_end) {
527 return;
528 }
529 // Must make the predecessors/successors match up with the
530 // BlockEnd's notion.
531 int i, n;
532 if (old_end != NULL) {
533 // disconnect from the old end
534 old_end->set_begin(NULL);
535
536 // disconnect this block from it's current successors
537 for (i = 0; i < _successors.length(); i++) {
538 _successors.at(i)->remove_predecessor(this);
539 }
540 }
541 _end = end;
542
543 _successors.clear();
544 // Now reset successors list based on BlockEnd
545 n = end->number_of_sux();
546 for (i = 0; i < n; i++) {
547 BlockBegin* sux = end->sux_at(i);
548 _successors.append(sux);
549 sux->_predecessors.append(this);
550 }
551 _end->set_begin(this);
552 }
553
554
555 void BlockBegin::disconnect_edge(BlockBegin* from, BlockBegin* to) {
556 // disconnect any edges between from and to
557 #ifndef PRODUCT
558 if (PrintIR && Verbose) {
559 tty->print_cr("Disconnected edge B%d -> B%d", from->block_id(), to->block_id());
560 }
561 #endif
562 for (int s = 0; s < from->number_of_sux();) {
563 BlockBegin* sux = from->sux_at(s);
564 if (sux == to) {
565 int index = sux->_predecessors.index_of(from);
566 if (index >= 0) {
567 sux->_predecessors.remove_at(index);
568 }
569 from->_successors.remove_at(s);
570 } else {
571 s++;
572 }
573 }
574 }
575
576
577 void BlockBegin::disconnect_from_graph() {
578 // disconnect this block from all other blocks
579 for (int p = 0; p < number_of_preds(); p++) {
580 pred_at(p)->remove_successor(this);
581 }
582 for (int s = 0; s < number_of_sux(); s++) {
583 sux_at(s)->remove_predecessor(this);
584 }
585 }
586
587 void BlockBegin::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
588 // modify predecessors before substituting successors
589 for (int i = 0; i < number_of_sux(); i++) {
590 if (sux_at(i) == old_sux) {
591 // remove old predecessor before adding new predecessor
592 // otherwise there is a dead predecessor in the list
593 new_sux->remove_predecessor(old_sux);
594 new_sux->add_predecessor(this);
595 }
596 }
597 old_sux->remove_predecessor(this);
598 end()->substitute_sux(old_sux, new_sux);
599 }
600
601
602
603 // In general it is not possible to calculate a value for the field "depth_first_number"
604 // of the inserted block, without recomputing the values of the other blocks
605 // in the CFG. Therefore the value of "depth_first_number" in BlockBegin becomes meaningless.
606 BlockBegin* BlockBegin::insert_block_between(BlockBegin* sux) {
607 // Try to make the bci close to a block with a single pred or sux,
608 // since this make the block layout algorithm work better.
609 int bci = -1;
610 if (sux->number_of_preds() == 1) {
611 bci = sux->bci();
612 } else {
613 bci = end()->bci();
614 }
615
616 BlockBegin* new_sux = new BlockBegin(bci);
617
618 // mark this block (special treatment when block order is computed)
619 new_sux->set(critical_edge_split_flag);
620
621 // This goto is not a safepoint.
622 Goto* e = new Goto(sux, false);
623 new_sux->set_next(e, bci);
624 new_sux->set_end(e);
625 // setup states
626 ValueStack* s = end()->state();
627 new_sux->set_state(s->copy());
628 e->set_state(s->copy());
629 assert(new_sux->state()->locals_size() == s->locals_size(), "local size mismatch!");
630 assert(new_sux->state()->stack_size() == s->stack_size(), "stack size mismatch!");
631 assert(new_sux->state()->locks_size() == s->locks_size(), "locks size mismatch!");
632
633 // link predecessor to new block
634 end()->substitute_sux(sux, new_sux);
635
636 // The ordering needs to be the same, so remove the link that the
637 // set_end call above added and substitute the new_sux for this
638 // block.
639 sux->remove_predecessor(new_sux);
640
641 // the successor could be the target of a switch so it might have
642 // multiple copies of this predecessor, so substitute the new_sux
643 // for the first and delete the rest.
644 bool assigned = false;
645 BlockList& list = sux->_predecessors;
646 for (int i = 0; i < list.length(); i++) {
647 BlockBegin** b = list.adr_at(i);
648 if (*b == this) {
649 if (assigned) {
650 list.remove_at(i);
651 // reprocess this index
652 i--;
653 } else {
654 assigned = true;
655 *b = new_sux;
656 }
657 // link the new block back to it's predecessors.
658 new_sux->add_predecessor(this);
659 }
660 }
661 assert(assigned == true, "should have assigned at least once");
662 return new_sux;
663 }
664
665
666 void BlockBegin::remove_successor(BlockBegin* pred) {
667 int idx;
668 while ((idx = _successors.index_of(pred)) >= 0) {
669 _successors.remove_at(idx);
670 }
671 }
672
673
674 void BlockBegin::add_predecessor(BlockBegin* pred) {
675 _predecessors.append(pred);
676 }
677
678
679 void BlockBegin::remove_predecessor(BlockBegin* pred) {
680 int idx;
681 while ((idx = _predecessors.index_of(pred)) >= 0) {
682 _predecessors.remove_at(idx);
683 }
684 }
685
686
687 void BlockBegin::add_exception_handler(BlockBegin* b) {
688 assert(b != NULL && (b->is_set(exception_entry_flag)), "exception handler must exist");
689 // add only if not in the list already
690 if (!_exception_handlers.contains(b)) _exception_handlers.append(b);
691 }
692
693 int BlockBegin::add_exception_state(ValueStack* state) {
694 assert(is_set(exception_entry_flag), "only for xhandlers");
695 if (_exception_states == NULL) {
696 _exception_states = new ValueStackStack(4);
697 }
698 _exception_states->append(state);
699 return _exception_states->length() - 1;
700 }
701
702
703 void BlockBegin::iterate_preorder(boolArray& mark, BlockClosure* closure) {
704 if (!mark.at(block_id())) {
705 mark.at_put(block_id(), true);
706 closure->block_do(this);
707 BlockEnd* e = end(); // must do this after block_do because block_do may change it!
708 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_preorder(mark, closure); }
709 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_preorder(mark, closure); }
710 }
711 }
712
713
714 void BlockBegin::iterate_postorder(boolArray& mark, BlockClosure* closure) {
715 if (!mark.at(block_id())) {
716 mark.at_put(block_id(), true);
717 BlockEnd* e = end();
718 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_postorder(mark, closure); }
719 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_postorder(mark, closure); }
720 closure->block_do(this);
721 }
722 }
723
724
725 void BlockBegin::iterate_preorder(BlockClosure* closure) {
726 boolArray mark(number_of_blocks(), false);
727 iterate_preorder(mark, closure);
728 }
729
730
731 void BlockBegin::iterate_postorder(BlockClosure* closure) {
732 boolArray mark(number_of_blocks(), false);
733 iterate_postorder(mark, closure);
734 }
735
736
737 void BlockBegin::block_values_do(ValueVisitor* f) {
738 for (Instruction* n = this; n != NULL; n = n->next()) n->values_do(f);
739 }
740
741
742 #ifndef PRODUCT
743 #define TRACE_PHI(code) if (PrintPhiFunctions) { code; }
744 #else
745 #define TRACE_PHI(coce)
746 #endif
747
748
749 bool BlockBegin::try_merge(ValueStack* new_state) {
750 TRACE_PHI(tty->print_cr("********** try_merge for block B%d", block_id()));
751
752 // local variables used for state iteration
753 int index;
754 Value new_value, existing_value;
755
756 ValueStack* existing_state = state();
757 if (existing_state == NULL) {
758 TRACE_PHI(tty->print_cr("first call of try_merge for this block"));
759
760 if (is_set(BlockBegin::was_visited_flag)) {
761 // this actually happens for complicated jsr/ret structures
762 return false; // BAILOUT in caller
763 }
764
765 // copy state because it is altered
766 new_state = new_state->copy();
767
768 // Use method liveness to invalidate dead locals
769 MethodLivenessResult liveness = new_state->scope()->method()->liveness_at_bci(bci());
770 if (liveness.is_valid()) {
771 assert((int)liveness.size() == new_state->locals_size(), "error in use of liveness");
772
773 for_each_local_value(new_state, index, new_value) {
774 if (!liveness.at(index) || new_value->type()->is_illegal()) {
775 new_state->invalidate_local(index);
776 TRACE_PHI(tty->print_cr("invalidating dead local %d", index));
777 }
778 }
779 }
780
781 if (is_set(BlockBegin::parser_loop_header_flag)) {
782 TRACE_PHI(tty->print_cr("loop header block, initializing phi functions"));
783
784 for_each_stack_value(new_state, index, new_value) {
785 new_state->setup_phi_for_stack(this, index);
786 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));
787 }
788
789 BitMap requires_phi_function = new_state->scope()->requires_phi_function();
790
791 for_each_local_value(new_state, index, new_value) {
792 bool requires_phi = requires_phi_function.at(index) || (new_value->type()->is_double_word() && requires_phi_function.at(index + 1));
793 if (requires_phi || !SelectivePhiFunctions) {
794 new_state->setup_phi_for_local(this, index);
795 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));
796 }
797 }
798 }
799
800 // initialize state of block
801 set_state(new_state);
802
803 } else if (existing_state->is_same_across_scopes(new_state)) {
804 TRACE_PHI(tty->print_cr("exisiting state found"));
805
806 // Inlining may cause the local state not to match up, so walk up
807 // the new state until we get to the same scope as the
808 // existing and then start processing from there.
809 while (existing_state->scope() != new_state->scope()) {
810 new_state = new_state->caller_state();
811 assert(new_state != NULL, "could not match up scopes");
812
813 assert(false, "check if this is necessary");
814 }
815
816 assert(existing_state->scope() == new_state->scope(), "not matching");
817 assert(existing_state->locals_size() == new_state->locals_size(), "not matching");
818 assert(existing_state->stack_size() == new_state->stack_size(), "not matching");
819
820 if (is_set(BlockBegin::was_visited_flag)) {
821 TRACE_PHI(tty->print_cr("loop header block, phis must be present"));
822
823 if (!is_set(BlockBegin::parser_loop_header_flag)) {
824 // this actually happens for complicated jsr/ret structures
825 return false; // BAILOUT in caller
826 }
827
828 for_each_local_value(existing_state, index, existing_value) {
829 Value new_value = new_state->local_at(index);
830 if (new_value == NULL || new_value->type()->tag() != existing_value->type()->tag()) {
831 // The old code invalidated the phi function here
832 // Because dead locals are replaced with NULL, this is a very rare case now, so simply bail out
833 return false; // BAILOUT in caller
834 }
835 }
836
837 #ifdef ASSERT
838 // check that all necessary phi functions are present
839 for_each_stack_value(existing_state, index, existing_value) {
840 assert(existing_value->as_Phi() != NULL && existing_value->as_Phi()->block() == this, "phi function required");
841 }
842 for_each_local_value(existing_state, index, existing_value) {
843 assert(existing_value == new_state->local_at(index) || (existing_value->as_Phi() != NULL && existing_value->as_Phi()->as_Phi()->block() == this), "phi function required");
844 }
845 #endif
846
847 } else {
848 TRACE_PHI(tty->print_cr("creating phi functions on demand"));
849
850 // create necessary phi functions for stack
851 for_each_stack_value(existing_state, index, existing_value) {
852 Value new_value = new_state->stack_at(index);
853 Phi* existing_phi = existing_value->as_Phi();
854
855 if (new_value != existing_value && (existing_phi == NULL || existing_phi->block() != this)) {
856 existing_state->setup_phi_for_stack(this, index);
857 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));
858 }
859 }
860
861 // create necessary phi functions for locals
862 for_each_local_value(existing_state, index, existing_value) {
863 Value new_value = new_state->local_at(index);
864 Phi* existing_phi = existing_value->as_Phi();
865
866 if (new_value == NULL || new_value->type()->tag() != existing_value->type()->tag()) {
867 existing_state->invalidate_local(index);
868 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
869 } else if (new_value != existing_value && (existing_phi == NULL || existing_phi->block() != this)) {
870 existing_state->setup_phi_for_local(this, index);
871 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));
872 }
873 }
874 }
875
876 assert(existing_state->caller_state() == new_state->caller_state(), "caller states must be equal");
877
878 } else {
879 assert(false, "stack or locks not matching (invalid bytecodes)");
880 return false;
881 }
882
883 TRACE_PHI(tty->print_cr("********** try_merge for block B%d successful", block_id()));
884
885 return true;
886 }
887
888
889 #ifndef PRODUCT
890 void BlockBegin::print_block() {
891 InstructionPrinter ip;
892 print_block(ip, false);
893 }
894
895
896 void BlockBegin::print_block(InstructionPrinter& ip, bool live_only) {
897 ip.print_instr(this); tty->cr();
898 ip.print_stack(this->state()); tty->cr();
899 ip.print_inline_level(this);
900 ip.print_head();
901 for (Instruction* n = next(); n != NULL; n = n->next()) {
902 if (!live_only || n->is_pinned() || n->use_count() > 0) {
903 ip.print_line(n);
904 }
905 }
906 tty->cr();
907 }
908 #endif // PRODUCT
909
910
911 // Implementation of BlockList
912
913 void BlockList::iterate_forward (BlockClosure* closure) {
914 const int l = length();
915 for (int i = 0; i < l; i++) closure->block_do(at(i));
916 }
917
918
919 void BlockList::iterate_backward(BlockClosure* closure) {
920 for (int i = length() - 1; i >= 0; i--) closure->block_do(at(i));
921 }
922
923
924 void BlockList::blocks_do(void f(BlockBegin*)) {
925 for (int i = length() - 1; i >= 0; i--) f(at(i));
926 }
927
928
929 void BlockList::values_do(ValueVisitor* f) {
930 for (int i = length() - 1; i >= 0; i--) at(i)->block_values_do(f);
931 }
932
933
934 #ifndef PRODUCT
935 void BlockList::print(bool cfg_only, bool live_only) {
936 InstructionPrinter ip;
937 for (int i = 0; i < length(); i++) {
938 BlockBegin* block = at(i);
939 if (cfg_only) {
940 ip.print_instr(block); tty->cr();
941 } else {
942 block->print_block(ip, live_only);
943 }
944 }
945 }
946 #endif // PRODUCT
947
948
949 // Implementation of BlockEnd
950
951 void BlockEnd::set_begin(BlockBegin* begin) {
952 BlockList* sux = NULL;
953 if (begin != NULL) {
954 sux = begin->successors();
955 } else if (_begin != NULL) {
956 // copy our sux list
957 BlockList* sux = new BlockList(_begin->number_of_sux());
958 for (int i = 0; i < _begin->number_of_sux(); i++) {
959 sux->append(_begin->sux_at(i));
960 }
961 }
962 _sux = sux;
963 _begin = begin;
964 }
965
966
967 void BlockEnd::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
968 substitute(*_sux, old_sux, new_sux);
969 }
970
971
972 void BlockEnd::other_values_do(ValueVisitor* f) {
973 if (state_before() != NULL) state_before()->values_do(f);
974 }
975
976
977 // Implementation of Phi
978
979 // Normal phi functions take their operands from the last instruction of the
980 // predecessor. Special handling is needed for xhanlder entries because there
981 // the state of arbitrary instructions are needed.
982
983 Value Phi::operand_at(int i) const {
984 ValueStack* state;
985 if (_block->is_set(BlockBegin::exception_entry_flag)) {
986 state = _block->exception_state_at(i);
987 } else {
988 state = _block->pred_at(i)->end()->state();
989 }
990 assert(state != NULL, "");
991
992 if (is_local()) {
993 return state->local_at(local_index());
994 } else {
995 return state->stack_at(stack_index());
996 }
997 }
998
999
1000 int Phi::operand_count() const {
1001 if (_block->is_set(BlockBegin::exception_entry_flag)) {
1002 return _block->number_of_exception_states();
1003 } else {
1004 return _block->number_of_preds();
1005 }
1006 }
1007
1008
1009 // Implementation of Throw
1010
1011 void Throw::state_values_do(ValueVisitor* f) {
1012 BlockEnd::state_values_do(f);
1013 }
1014
1015 void ProfileInvoke::state_values_do(ValueVisitor* f) {
1016 if (state() != NULL) state()->values_do(f);
1017 }