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