1 /*
2 * Copyright 1999-2010 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any 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 int Instruction::_next_id = 0;
33
34 #ifdef ASSERT
35 void Instruction::create_hi_word() {
36 assert(type()->is_double_word() && _hi_word == NULL, "only double word has high word");
37 _hi_word = new HiWord(this);
38 }
39 #endif
40
41 Instruction::Condition Instruction::mirror(Condition cond) {
42 switch (cond) {
43 case eql: return eql;
44 case neq: return neq;
45 case lss: return gtr;
46 case leq: return geq;
47 case gtr: return lss;
48 case geq: return leq;
49 }
50 ShouldNotReachHere();
51 return eql;
52 }
53
54
55 Instruction::Condition Instruction::negate(Condition cond) {
56 switch (cond) {
57 case eql: return neq;
58 case neq: return eql;
59 case lss: return geq;
60 case leq: return gtr;
61 case gtr: return leq;
62 case geq: return lss;
63 }
64 ShouldNotReachHere();
65 return eql;
66 }
67
68
69 Instruction* Instruction::prev(BlockBegin* block) {
70 Instruction* p = NULL;
71 Instruction* q = block;
72 while (q != this) {
73 assert(q != NULL, "this is not in the block's instruction list");
74 p = q; q = q->next();
75 }
76 return p;
77 }
78
79
80 #ifndef PRODUCT
81 void Instruction::print() {
82 InstructionPrinter ip;
83 print(ip);
84 }
85
86
87 void Instruction::print_line() {
88 InstructionPrinter ip;
89 ip.print_line(this);
90 }
91
92
93 void Instruction::print(InstructionPrinter& ip) {
94 ip.print_head();
95 ip.print_line(this);
96 tty->cr();
97 }
98 #endif // PRODUCT
99
100
101 // perform constant and interval tests on index value
102 bool AccessIndexed::compute_needs_range_check() {
103 Constant* clength = length()->as_Constant();
104 Constant* cindex = index()->as_Constant();
105 if (clength && cindex) {
106 IntConstant* l = clength->type()->as_IntConstant();
107 IntConstant* i = cindex->type()->as_IntConstant();
108 if (l && i && i->value() < l->value() && i->value() >= 0) {
109 return false;
110 }
111 }
112 return true;
113 }
114
115
116 ciType* LoadIndexed::exact_type() const {
117 ciType* array_type = array()->exact_type();
118 if (array_type == NULL) {
119 return NULL;
120 }
121 assert(array_type->is_array_klass(), "what else?");
122 ciArrayKlass* ak = (ciArrayKlass*)array_type;
123
124 if (ak->element_type()->is_instance_klass()) {
125 ciInstanceKlass* ik = (ciInstanceKlass*)ak->element_type();
126 if (ik->is_loaded() && ik->is_final()) {
127 return ik;
128 }
129 }
130 return NULL;
131 }
132
133
134 ciType* LoadIndexed::declared_type() const {
135 ciType* array_type = array()->declared_type();
136 if (array_type == NULL) {
137 return NULL;
138 }
139 assert(array_type->is_array_klass(), "what else?");
140 ciArrayKlass* ak = (ciArrayKlass*)array_type;
141 return ak->element_type();
142 }
143
144
145 ciType* LoadField::declared_type() const {
146 return field()->type();
147 }
148
149
150 ciType* LoadField::exact_type() const {
151 ciType* type = declared_type();
152 // for primitive arrays, the declared type is the exact type
153 if (type->is_type_array_klass()) {
154 return type;
155 }
156 if (type->is_instance_klass()) {
157 ciInstanceKlass* ik = (ciInstanceKlass*)type;
158 if (ik->is_loaded() && ik->is_final()) {
159 return type;
160 }
161 }
162 return NULL;
163 }
164
165
166 ciType* NewTypeArray::exact_type() const {
167 return ciTypeArrayKlass::make(elt_type());
168 }
169
170
171 ciType* NewObjectArray::exact_type() const {
172 return ciObjArrayKlass::make(klass());
173 }
174
175
176 ciType* NewInstance::exact_type() const {
177 return klass();
178 }
179
180
181 ciType* CheckCast::declared_type() const {
182 return klass();
183 }
184
185 ciType* CheckCast::exact_type() const {
186 if (klass()->is_instance_klass()) {
187 ciInstanceKlass* ik = (ciInstanceKlass*)klass();
188 if (ik->is_loaded() && ik->is_final()) {
189 return ik;
190 }
191 }
192 return NULL;
193 }
194
195
196 void ArithmeticOp::other_values_do(void f(Value*)) {
197 if (lock_stack() != NULL) lock_stack()->values_do(f);
198 }
199
200 void NullCheck::other_values_do(void f(Value*)) {
201 lock_stack()->values_do(f);
202 }
203
204 void AccessArray::other_values_do(void f(Value*)) {
205 if (lock_stack() != NULL) lock_stack()->values_do(f);
206 }
207
208
209 // Implementation of AccessField
210
211 void AccessField::other_values_do(void f(Value*)) {
212 if (state_before() != NULL) state_before()->values_do(f);
213 if (lock_stack() != NULL) lock_stack()->values_do(f);
214 }
215
216
217 // Implementation of StoreIndexed
218
219 IRScope* StoreIndexed::scope() const {
220 return lock_stack()->scope();
221 }
222
223
224 // Implementation of ArithmeticOp
225
226 bool ArithmeticOp::is_commutative() const {
227 switch (op()) {
228 case Bytecodes::_iadd: // fall through
229 case Bytecodes::_ladd: // fall through
230 case Bytecodes::_fadd: // fall through
231 case Bytecodes::_dadd: // fall through
232 case Bytecodes::_imul: // fall through
233 case Bytecodes::_lmul: // fall through
234 case Bytecodes::_fmul: // fall through
235 case Bytecodes::_dmul: return true;
236 }
237 return false;
238 }
239
240
241 bool ArithmeticOp::can_trap() const {
242 switch (op()) {
243 case Bytecodes::_idiv: // fall through
244 case Bytecodes::_ldiv: // fall through
245 case Bytecodes::_irem: // fall through
246 case Bytecodes::_lrem: return true;
247 }
248 return false;
249 }
250
251
252 // Implementation of LogicOp
253
254 bool LogicOp::is_commutative() const {
255 #ifdef ASSERT
256 switch (op()) {
257 case Bytecodes::_iand: // fall through
258 case Bytecodes::_land: // fall through
259 case Bytecodes::_ior : // fall through
260 case Bytecodes::_lor : // fall through
261 case Bytecodes::_ixor: // fall through
262 case Bytecodes::_lxor: break;
263 default : ShouldNotReachHere();
264 }
265 #endif
266 // all LogicOps are commutative
267 return true;
268 }
269
270
271 // Implementation of CompareOp
272
273 void CompareOp::other_values_do(void f(Value*)) {
274 if (state_before() != NULL) state_before()->values_do(f);
275 }
276
277
278 // Implementation of IfOp
279
280 bool IfOp::is_commutative() const {
281 return cond() == eql || cond() == neq;
282 }
283
284
285 // Implementation of StateSplit
286
287 void StateSplit::substitute(BlockList& list, BlockBegin* old_block, BlockBegin* new_block) {
288 NOT_PRODUCT(bool assigned = false;)
289 for (int i = 0; i < list.length(); i++) {
290 BlockBegin** b = list.adr_at(i);
291 if (*b == old_block) {
292 *b = new_block;
293 NOT_PRODUCT(assigned = true;)
294 }
295 }
296 assert(assigned == true, "should have assigned at least once");
297 }
298
299
300 IRScope* StateSplit::scope() const {
301 return _state->scope();
302 }
303
304
305 void StateSplit::state_values_do(void f(Value*)) {
306 if (state() != NULL) state()->values_do(f);
307 }
308
309
310 void BlockBegin::state_values_do(void f(Value*)) {
311 StateSplit::state_values_do(f);
312
313 if (is_set(BlockBegin::exception_entry_flag)) {
314 for (int i = 0; i < number_of_exception_states(); i++) {
315 exception_state_at(i)->values_do(f);
316 }
317 }
318 }
319
320
321 void MonitorEnter::state_values_do(void f(Value*)) {
322 StateSplit::state_values_do(f);
323 _lock_stack_before->values_do(f);
324 }
325
326
327 void Intrinsic::state_values_do(void f(Value*)) {
328 StateSplit::state_values_do(f);
329 if (lock_stack() != NULL) lock_stack()->values_do(f);
330 }
331
332
333 // Implementation of Invoke
334
335
336 Invoke::Invoke(Bytecodes::Code code, ValueType* result_type, Value recv, Values* args,
337 int vtable_index, ciMethod* target, ValueStack* state_before)
338 : StateSplit(result_type)
339 , _code(code)
340 , _recv(recv)
341 , _args(args)
342 , _vtable_index(vtable_index)
343 , _target(target)
344 , _state_before(state_before)
345 {
346 set_flag(TargetIsLoadedFlag, target->is_loaded());
347 set_flag(TargetIsFinalFlag, target_is_loaded() && target->is_final_method());
348 set_flag(TargetIsStrictfpFlag, target_is_loaded() && target->is_strict());
349
350 assert(args != NULL, "args must exist");
351 #ifdef ASSERT
352 values_do(assert_value);
353 #endif // ASSERT
354
355 // provide an initial guess of signature size.
356 _signature = new BasicTypeList(number_of_arguments() + (has_receiver() ? 1 : 0));
357 if (has_receiver()) {
358 _signature->append(as_BasicType(receiver()->type()));
359 } else if (is_invokedynamic()) {
360 // Add the synthetic MethodHandle argument to the signature.
361 _signature->append(T_OBJECT);
362 }
363 for (int i = 0; i < number_of_arguments(); i++) {
364 ValueType* t = argument_at(i)->type();
365 BasicType bt = as_BasicType(t);
366 _signature->append(bt);
367 }
368 }
369
370
371 void Invoke::state_values_do(void f(Value*)) {
372 StateSplit::state_values_do(f);
373 if (state_before() != NULL) state_before()->values_do(f);
374 if (state() != NULL) state()->values_do(f);
375 }
376
377
378 // Implementation of Contant
379 intx Constant::hash() const {
380 if (_state == NULL) {
381 switch (type()->tag()) {
382 case intTag:
383 return HASH2(name(), type()->as_IntConstant()->value());
384 case longTag:
385 {
386 jlong temp = type()->as_LongConstant()->value();
387 return HASH3(name(), high(temp), low(temp));
388 }
389 case floatTag:
390 return HASH2(name(), jint_cast(type()->as_FloatConstant()->value()));
391 case doubleTag:
392 {
393 jlong temp = jlong_cast(type()->as_DoubleConstant()->value());
394 return HASH3(name(), high(temp), low(temp));
395 }
396 case objectTag:
397 assert(type()->as_ObjectType()->is_loaded(), "can't handle unloaded values");
398 return HASH2(name(), type()->as_ObjectType()->constant_value());
399 }
400 }
401 return 0;
402 }
403
404 bool Constant::is_equal(Value v) const {
405 if (v->as_Constant() == NULL) return false;
406
407 switch (type()->tag()) {
408 case intTag:
409 {
410 IntConstant* t1 = type()->as_IntConstant();
411 IntConstant* t2 = v->type()->as_IntConstant();
412 return (t1 != NULL && t2 != NULL &&
413 t1->value() == t2->value());
414 }
415 case longTag:
416 {
417 LongConstant* t1 = type()->as_LongConstant();
418 LongConstant* t2 = v->type()->as_LongConstant();
419 return (t1 != NULL && t2 != NULL &&
420 t1->value() == t2->value());
421 }
422 case floatTag:
423 {
424 FloatConstant* t1 = type()->as_FloatConstant();
425 FloatConstant* t2 = v->type()->as_FloatConstant();
426 return (t1 != NULL && t2 != NULL &&
427 jint_cast(t1->value()) == jint_cast(t2->value()));
428 }
429 case doubleTag:
430 {
431 DoubleConstant* t1 = type()->as_DoubleConstant();
432 DoubleConstant* t2 = v->type()->as_DoubleConstant();
433 return (t1 != NULL && t2 != NULL &&
434 jlong_cast(t1->value()) == jlong_cast(t2->value()));
435 }
436 case objectTag:
437 {
438 ObjectType* t1 = type()->as_ObjectType();
439 ObjectType* t2 = v->type()->as_ObjectType();
440 return (t1 != NULL && t2 != NULL &&
441 t1->is_loaded() && t2->is_loaded() &&
442 t1->constant_value() == t2->constant_value());
443 }
444 }
445 return false;
446 }
447
448
449 BlockBegin* Constant::compare(Instruction::Condition cond, Value right,
450 BlockBegin* true_sux, BlockBegin* false_sux) {
451 Constant* rc = right->as_Constant();
452 // other is not a constant
453 if (rc == NULL) return NULL;
454
455 ValueType* lt = type();
456 ValueType* rt = rc->type();
457 // different types
458 if (lt->base() != rt->base()) return NULL;
459 switch (lt->tag()) {
460 case intTag: {
461 int x = lt->as_IntConstant()->value();
462 int y = rt->as_IntConstant()->value();
463 switch (cond) {
464 case If::eql: return x == y ? true_sux : false_sux;
465 case If::neq: return x != y ? true_sux : false_sux;
466 case If::lss: return x < y ? true_sux : false_sux;
467 case If::leq: return x <= y ? true_sux : false_sux;
468 case If::gtr: return x > y ? true_sux : false_sux;
469 case If::geq: return x >= y ? true_sux : false_sux;
470 }
471 break;
472 }
473 case longTag: {
474 jlong x = lt->as_LongConstant()->value();
475 jlong y = rt->as_LongConstant()->value();
476 switch (cond) {
477 case If::eql: return x == y ? true_sux : false_sux;
478 case If::neq: return x != y ? true_sux : false_sux;
479 case If::lss: return x < y ? true_sux : false_sux;
480 case If::leq: return x <= y ? true_sux : false_sux;
481 case If::gtr: return x > y ? true_sux : false_sux;
482 case If::geq: return x >= y ? true_sux : false_sux;
483 }
484 break;
485 }
486 case objectTag: {
487 ciObject* xvalue = lt->as_ObjectType()->constant_value();
488 ciObject* yvalue = rt->as_ObjectType()->constant_value();
489 assert(xvalue != NULL && yvalue != NULL, "not constants");
490 if (xvalue->is_loaded() && yvalue->is_loaded()) {
491 switch (cond) {
492 case If::eql: return xvalue == yvalue ? true_sux : false_sux;
493 case If::neq: return xvalue != yvalue ? true_sux : false_sux;
494 }
495 }
496 break;
497 }
498 }
499 return NULL;
500 }
501
502
503 void Constant::other_values_do(void f(Value*)) {
504 if (state() != NULL) state()->values_do(f);
505 }
506
507
508 // Implementation of NewArray
509
510 void NewArray::other_values_do(void f(Value*)) {
511 if (state_before() != NULL) state_before()->values_do(f);
512 }
513
514
515 // Implementation of TypeCheck
516
517 void TypeCheck::other_values_do(void f(Value*)) {
518 if (state_before() != NULL) state_before()->values_do(f);
519 }
520
521
522 // Implementation of BlockBegin
523
524 int BlockBegin::_next_block_id = 0;
525
526
527 void BlockBegin::set_end(BlockEnd* end) {
528 assert(end != NULL, "should not reset block end to NULL");
529 BlockEnd* old_end = _end;
530 if (end == old_end) {
531 return;
532 }
533 // Must make the predecessors/successors match up with the
534 // BlockEnd's notion.
535 int i, n;
536 if (old_end != NULL) {
537 // disconnect from the old end
538 old_end->set_begin(NULL);
539
540 // disconnect this block from it's current successors
541 for (i = 0; i < _successors.length(); i++) {
542 _successors.at(i)->remove_predecessor(this);
543 }
544 }
545 _end = end;
546
547 _successors.clear();
548 // Now reset successors list based on BlockEnd
549 n = end->number_of_sux();
550 for (i = 0; i < n; i++) {
551 BlockBegin* sux = end->sux_at(i);
552 _successors.append(sux);
553 sux->_predecessors.append(this);
554 }
555 _end->set_begin(this);
556 }
557
558
559 void BlockBegin::disconnect_edge(BlockBegin* from, BlockBegin* to) {
560 // disconnect any edges between from and to
561 #ifndef PRODUCT
562 if (PrintIR && Verbose) {
563 tty->print_cr("Disconnected edge B%d -> B%d", from->block_id(), to->block_id());
564 }
565 #endif
566 for (int s = 0; s < from->number_of_sux();) {
567 BlockBegin* sux = from->sux_at(s);
568 if (sux == to) {
569 int index = sux->_predecessors.index_of(from);
570 if (index >= 0) {
571 sux->_predecessors.remove_at(index);
572 }
573 from->_successors.remove_at(s);
574 } else {
575 s++;
576 }
577 }
578 }
579
580
581 void BlockBegin::disconnect_from_graph() {
582 // disconnect this block from all other blocks
583 for (int p = 0; p < number_of_preds(); p++) {
584 pred_at(p)->remove_successor(this);
585 }
586 for (int s = 0; s < number_of_sux(); s++) {
587 sux_at(s)->remove_predecessor(this);
588 }
589 }
590
591 void BlockBegin::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
592 // modify predecessors before substituting successors
593 for (int i = 0; i < number_of_sux(); i++) {
594 if (sux_at(i) == old_sux) {
595 // remove old predecessor before adding new predecessor
596 // otherwise there is a dead predecessor in the list
597 new_sux->remove_predecessor(old_sux);
598 new_sux->add_predecessor(this);
599 }
600 }
601 old_sux->remove_predecessor(this);
602 end()->substitute_sux(old_sux, new_sux);
603 }
604
605
606
607 // In general it is not possible to calculate a value for the field "depth_first_number"
608 // of the inserted block, without recomputing the values of the other blocks
609 // in the CFG. Therefore the value of "depth_first_number" in BlockBegin becomes meaningless.
610 BlockBegin* BlockBegin::insert_block_between(BlockBegin* sux) {
611 // Try to make the bci close to a block with a single pred or sux,
612 // since this make the block layout algorithm work better.
613 int bci = -1;
614 if (sux->number_of_preds() == 1) {
615 bci = sux->bci();
616 } else {
617 bci = end()->bci();
618 }
619
620 BlockBegin* new_sux = new BlockBegin(bci);
621
622 // mark this block (special treatment when block order is computed)
623 new_sux->set(critical_edge_split_flag);
624
625 // This goto is not a safepoint.
626 Goto* e = new Goto(sux, false);
627 new_sux->set_next(e, bci);
628 new_sux->set_end(e);
629 // setup states
630 ValueStack* s = end()->state();
631 new_sux->set_state(s->copy());
632 e->set_state(s->copy());
633 assert(new_sux->state()->locals_size() == s->locals_size(), "local size mismatch!");
634 assert(new_sux->state()->stack_size() == s->stack_size(), "stack size mismatch!");
635 assert(new_sux->state()->locks_size() == s->locks_size(), "locks size mismatch!");
636
637 // link predecessor to new block
638 end()->substitute_sux(sux, new_sux);
639
640 // The ordering needs to be the same, so remove the link that the
641 // set_end call above added and substitute the new_sux for this
642 // block.
643 sux->remove_predecessor(new_sux);
644
645 // the successor could be the target of a switch so it might have
646 // multiple copies of this predecessor, so substitute the new_sux
647 // for the first and delete the rest.
648 bool assigned = false;
649 BlockList& list = sux->_predecessors;
650 for (int i = 0; i < list.length(); i++) {
651 BlockBegin** b = list.adr_at(i);
652 if (*b == this) {
653 if (assigned) {
654 list.remove_at(i);
655 // reprocess this index
656 i--;
657 } else {
658 assigned = true;
659 *b = new_sux;
660 }
661 // link the new block back to it's predecessors.
662 new_sux->add_predecessor(this);
663 }
664 }
665 assert(assigned == true, "should have assigned at least once");
666 return new_sux;
667 }
668
669
670 void BlockBegin::remove_successor(BlockBegin* pred) {
671 int idx;
672 while ((idx = _successors.index_of(pred)) >= 0) {
673 _successors.remove_at(idx);
674 }
675 }
676
677
678 void BlockBegin::add_predecessor(BlockBegin* pred) {
679 _predecessors.append(pred);
680 }
681
682
683 void BlockBegin::remove_predecessor(BlockBegin* pred) {
684 int idx;
685 while ((idx = _predecessors.index_of(pred)) >= 0) {
686 _predecessors.remove_at(idx);
687 }
688 }
689
690
691 void BlockBegin::add_exception_handler(BlockBegin* b) {
692 assert(b != NULL && (b->is_set(exception_entry_flag)), "exception handler must exist");
693 // add only if not in the list already
694 if (!_exception_handlers.contains(b)) _exception_handlers.append(b);
695 }
696
697 int BlockBegin::add_exception_state(ValueStack* state) {
698 assert(is_set(exception_entry_flag), "only for xhandlers");
699 if (_exception_states == NULL) {
700 _exception_states = new ValueStackStack(4);
701 }
702 _exception_states->append(state);
703 return _exception_states->length() - 1;
704 }
705
706
707 void BlockBegin::iterate_preorder(boolArray& mark, BlockClosure* closure) {
708 if (!mark.at(block_id())) {
709 mark.at_put(block_id(), true);
710 closure->block_do(this);
711 BlockEnd* e = end(); // must do this after block_do because block_do may change it!
712 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_preorder(mark, closure); }
713 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_preorder(mark, closure); }
714 }
715 }
716
717
718 void BlockBegin::iterate_postorder(boolArray& mark, BlockClosure* closure) {
719 if (!mark.at(block_id())) {
720 mark.at_put(block_id(), true);
721 BlockEnd* e = end();
722 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_postorder(mark, closure); }
723 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_postorder(mark, closure); }
724 closure->block_do(this);
725 }
726 }
727
728
729 void BlockBegin::iterate_preorder(BlockClosure* closure) {
730 boolArray mark(number_of_blocks(), false);
731 iterate_preorder(mark, closure);
732 }
733
734
735 void BlockBegin::iterate_postorder(BlockClosure* closure) {
736 boolArray mark(number_of_blocks(), false);
737 iterate_postorder(mark, closure);
738 }
739
740
741 void BlockBegin::block_values_do(void f(Value*)) {
742 for (Instruction* n = this; n != NULL; n = n->next()) n->values_do(f);
743 }
744
745
746 #ifndef PRODUCT
747 #define TRACE_PHI(code) if (PrintPhiFunctions) { code; }
748 #else
749 #define TRACE_PHI(coce)
750 #endif
751
752
753 bool BlockBegin::try_merge(ValueStack* new_state) {
754 TRACE_PHI(tty->print_cr("********** try_merge for block B%d", block_id()));
755
756 // local variables used for state iteration
757 int index;
758 Value new_value, existing_value;
759
760 ValueStack* existing_state = state();
761 if (existing_state == NULL) {
762 TRACE_PHI(tty->print_cr("first call of try_merge for this block"));
763
764 if (is_set(BlockBegin::was_visited_flag)) {
765 // this actually happens for complicated jsr/ret structures
766 return false; // BAILOUT in caller
767 }
768
769 // copy state because it is altered
770 new_state = new_state->copy();
771
772 // Use method liveness to invalidate dead locals
773 MethodLivenessResult liveness = new_state->scope()->method()->liveness_at_bci(bci());
774 if (liveness.is_valid()) {
775 assert((int)liveness.size() == new_state->locals_size(), "error in use of liveness");
776
777 for_each_local_value(new_state, index, new_value) {
778 if (!liveness.at(index) || new_value->type()->is_illegal()) {
779 new_state->invalidate_local(index);
780 TRACE_PHI(tty->print_cr("invalidating dead local %d", index));
781 }
782 }
783 }
784
785 if (is_set(BlockBegin::parser_loop_header_flag)) {
786 TRACE_PHI(tty->print_cr("loop header block, initializing phi functions"));
787
788 for_each_stack_value(new_state, index, new_value) {
789 new_state->setup_phi_for_stack(this, index);
790 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));
791 }
792
793 BitMap requires_phi_function = new_state->scope()->requires_phi_function();
794
795 for_each_local_value(new_state, index, new_value) {
796 bool requires_phi = requires_phi_function.at(index) || (new_value->type()->is_double_word() && requires_phi_function.at(index + 1));
797 if (requires_phi || !SelectivePhiFunctions) {
798 new_state->setup_phi_for_local(this, index);
799 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));
800 }
801 }
802 }
803
804 // initialize state of block
805 set_state(new_state);
806
807 } else if (existing_state->is_same_across_scopes(new_state)) {
808 TRACE_PHI(tty->print_cr("exisiting state found"));
809
810 // Inlining may cause the local state not to match up, so walk up
811 // the new state until we get to the same scope as the
812 // existing and then start processing from there.
813 while (existing_state->scope() != new_state->scope()) {
814 new_state = new_state->caller_state();
815 assert(new_state != NULL, "could not match up scopes");
816
817 assert(false, "check if this is necessary");
818 }
819
820 assert(existing_state->scope() == new_state->scope(), "not matching");
821 assert(existing_state->locals_size() == new_state->locals_size(), "not matching");
822 assert(existing_state->stack_size() == new_state->stack_size(), "not matching");
823
824 if (is_set(BlockBegin::was_visited_flag)) {
825 TRACE_PHI(tty->print_cr("loop header block, phis must be present"));
826
827 if (!is_set(BlockBegin::parser_loop_header_flag)) {
828 // this actually happens for complicated jsr/ret structures
829 return false; // BAILOUT in caller
830 }
831
832 for_each_local_value(existing_state, index, existing_value) {
833 Value new_value = new_state->local_at(index);
834 if (new_value == NULL || new_value->type()->tag() != existing_value->type()->tag()) {
835 // The old code invalidated the phi function here
836 // Because dead locals are replaced with NULL, this is a very rare case now, so simply bail out
837 return false; // BAILOUT in caller
838 }
839 }
840
841 #ifdef ASSERT
842 // check that all necessary phi functions are present
843 for_each_stack_value(existing_state, index, existing_value) {
844 assert(existing_value->as_Phi() != NULL && existing_value->as_Phi()->block() == this, "phi function required");
845 }
846 for_each_local_value(existing_state, index, existing_value) {
847 assert(existing_value == new_state->local_at(index) || (existing_value->as_Phi() != NULL && existing_value->as_Phi()->as_Phi()->block() == this), "phi function required");
848 }
849 #endif
850
851 } else {
852 TRACE_PHI(tty->print_cr("creating phi functions on demand"));
853
854 // create necessary phi functions for stack
855 for_each_stack_value(existing_state, index, existing_value) {
856 Value new_value = new_state->stack_at(index);
857 Phi* existing_phi = existing_value->as_Phi();
858
859 if (new_value != existing_value && (existing_phi == NULL || existing_phi->block() != this)) {
860 existing_state->setup_phi_for_stack(this, index);
861 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));
862 }
863 }
864
865 // create necessary phi functions for locals
866 for_each_local_value(existing_state, index, existing_value) {
867 Value new_value = new_state->local_at(index);
868 Phi* existing_phi = existing_value->as_Phi();
869
870 if (new_value == NULL || new_value->type()->tag() != existing_value->type()->tag()) {
871 existing_state->invalidate_local(index);
872 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
873 } else if (new_value != existing_value && (existing_phi == NULL || existing_phi->block() != this)) {
874 existing_state->setup_phi_for_local(this, index);
875 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));
876 }
877 }
878 }
879
880 assert(existing_state->caller_state() == new_state->caller_state(), "caller states must be equal");
881
882 } else {
883 assert(false, "stack or locks not matching (invalid bytecodes)");
884 return false;
885 }
886
887 TRACE_PHI(tty->print_cr("********** try_merge for block B%d successful", block_id()));
888
889 return true;
890 }
891
892
893 #ifndef PRODUCT
894 void BlockBegin::print_block() {
895 InstructionPrinter ip;
896 print_block(ip, false);
897 }
898
899
900 void BlockBegin::print_block(InstructionPrinter& ip, bool live_only) {
901 ip.print_instr(this); tty->cr();
902 ip.print_stack(this->state()); tty->cr();
903 ip.print_inline_level(this);
904 ip.print_head();
905 for (Instruction* n = next(); n != NULL; n = n->next()) {
906 if (!live_only || n->is_pinned() || n->use_count() > 0) {
907 ip.print_line(n);
908 }
909 }
910 tty->cr();
911 }
912 #endif // PRODUCT
913
914
915 // Implementation of BlockList
916
917 void BlockList::iterate_forward (BlockClosure* closure) {
918 const int l = length();
919 for (int i = 0; i < l; i++) closure->block_do(at(i));
920 }
921
922
923 void BlockList::iterate_backward(BlockClosure* closure) {
924 for (int i = length() - 1; i >= 0; i--) closure->block_do(at(i));
925 }
926
927
928 void BlockList::blocks_do(void f(BlockBegin*)) {
929 for (int i = length() - 1; i >= 0; i--) f(at(i));
930 }
931
932
933 void BlockList::values_do(void f(Value*)) {
934 for (int i = length() - 1; i >= 0; i--) at(i)->block_values_do(f);
935 }
936
937
938 #ifndef PRODUCT
939 void BlockList::print(bool cfg_only, bool live_only) {
940 InstructionPrinter ip;
941 for (int i = 0; i < length(); i++) {
942 BlockBegin* block = at(i);
943 if (cfg_only) {
944 ip.print_instr(block); tty->cr();
945 } else {
946 block->print_block(ip, live_only);
947 }
948 }
949 }
950 #endif // PRODUCT
951
952
953 // Implementation of BlockEnd
954
955 void BlockEnd::set_begin(BlockBegin* begin) {
956 BlockList* sux = NULL;
957 if (begin != NULL) {
958 sux = begin->successors();
959 } else if (_begin != NULL) {
960 // copy our sux list
961 BlockList* sux = new BlockList(_begin->number_of_sux());
962 for (int i = 0; i < _begin->number_of_sux(); i++) {
963 sux->append(_begin->sux_at(i));
964 }
965 }
966 _sux = sux;
967 _begin = begin;
968 }
969
970
971 void BlockEnd::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
972 substitute(*_sux, old_sux, new_sux);
973 }
974
975
976 void BlockEnd::other_values_do(void f(Value*)) {
977 if (state_before() != NULL) state_before()->values_do(f);
978 }
979
980
981 // Implementation of Phi
982
983 // Normal phi functions take their operands from the last instruction of the
984 // predecessor. Special handling is needed for xhanlder entries because there
985 // the state of arbitrary instructions are needed.
986
987 Value Phi::operand_at(int i) const {
988 ValueStack* state;
989 if (_block->is_set(BlockBegin::exception_entry_flag)) {
990 state = _block->exception_state_at(i);
991 } else {
992 state = _block->pred_at(i)->end()->state();
993 }
994 assert(state != NULL, "");
995
996 if (is_local()) {
997 return state->local_at(local_index());
998 } else {
999 return state->stack_at(stack_index());
1000 }
1001 }
1002
1003
1004 int Phi::operand_count() const {
1005 if (_block->is_set(BlockBegin::exception_entry_flag)) {
1006 return _block->number_of_exception_states();
1007 } else {
1008 return _block->number_of_preds();
1009 }
1010 }
1011
1012
1013 // Implementation of Throw
1014
1015 void Throw::state_values_do(void f(Value*)) {
1016 BlockEnd::state_values_do(f);
1017 }