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() || element_klass->is_interface()) {
163 // Array covariance:
164 // (ValueType[] <: Object[])
165 // (ValueType[] <: <any interface>[])
166 // We will add a runtime check for flat-ness.
167 return true;
168 }
169 }
170 }
171 }
172
173 return false;
174 }
175
176 #ifndef PRODUCT
177 void Instruction::check_state(ValueStack* state) {
178 if (state != NULL) {
179 state->verify();
180 }
181 }
182
183
184 void Instruction::print() {
185 InstructionPrinter ip;
186 print(ip);
187 }
188
189
190 void Instruction::print_line() {
191 InstructionPrinter ip;
192 ip.print_line(this);
193 }
194
195
196 void Instruction::print(InstructionPrinter& ip) {
197 ip.print_head();
198 ip.print_line(this);
199 tty->cr();
200 }
201 #endif // PRODUCT
202
203
204 // perform constant and interval tests on index value
205 bool AccessIndexed::compute_needs_range_check() {
206 if (length()) {
207 Constant* clength = length()->as_Constant();
208 Constant* cindex = index()->as_Constant();
209 if (clength && cindex) {
210 IntConstant* l = clength->type()->as_IntConstant();
211 IntConstant* i = cindex->type()->as_IntConstant();
212 if (l && i && i->value() < l->value() && i->value() >= 0) {
213 return false;
214 }
215 }
216 }
217
218 if (!this->check_flag(NeedsRangeCheckFlag)) {
219 return false;
220 }
221
222 return true;
223 }
224
225
226 ciType* Constant::exact_type() const {
227 if (type()->is_object() && type()->as_ObjectType()->is_loaded()) {
228 return type()->as_ObjectType()->exact_type();
229 }
230 return NULL;
231 }
232
233 ciType* LoadIndexed::exact_type() const {
234 ciType* array_type = array()->exact_type();
235 if (array_type != NULL) {
236 assert(array_type->is_array_klass(), "what else?");
237 ciArrayKlass* ak = (ciArrayKlass*)array_type;
238
239 if (ak->element_type()->is_instance_klass()) {
240 ciInstanceKlass* ik = (ciInstanceKlass*)ak->element_type();
241 if (ik->is_loaded() && ik->is_final()) {
242 return ik;
243 }
244 }
245 }
246 return Instruction::exact_type();
247 }
248
249
250 ciType* LoadIndexed::declared_type() const {
251 ciType* array_type = array()->declared_type();
252 if (array_type == NULL || !array_type->is_loaded()) {
253 return NULL;
254 }
255 assert(array_type->is_array_klass(), "what else?");
256 ciArrayKlass* ak = (ciArrayKlass*)array_type;
257 return ak->element_type();
258 }
259
260
261 ciType* LoadField::declared_type() const {
262 return field()->type();
263 }
264
265
266 ciType* NewTypeArray::exact_type() const {
267 return ciTypeArrayKlass::make(elt_type());
268 }
269
270 ciType* NewObjectArray::exact_type() const {
271 ciKlass* element_klass = klass();
272 if (element_klass->is_valuetype()) {
273 return ciValueArrayKlass::make(element_klass);
274 } else {
275 return ciObjArrayKlass::make(element_klass);
276 }
277 }
278
279 ciType* NewMultiArray::exact_type() const {
280 return _klass;
281 }
282
283 ciType* NewArray::declared_type() const {
284 return exact_type();
285 }
286
287 ciType* NewInstance::exact_type() const {
288 return klass();
289 }
290
291 ciType* NewInstance::declared_type() const {
292 return exact_type();
293 }
294
295 Value NewValueTypeInstance::depends_on() {
296 if (_depends_on != this) {
297 if (_depends_on->as_NewValueTypeInstance() != NULL) {
298 return _depends_on->as_NewValueTypeInstance()->depends_on();
299 }
300 }
301 return _depends_on;
302 }
303
304 ciType* NewValueTypeInstance::exact_type() const {
305 return klass();
306 }
307
308 ciType* NewValueTypeInstance::declared_type() const {
309 return exact_type();
310 }
311
312 ciType* CheckCast::declared_type() const {
313 return klass();
314 }
315
316 // Implementation of ArithmeticOp
317
318 bool ArithmeticOp::is_commutative() const {
319 switch (op()) {
320 case Bytecodes::_iadd: // fall through
321 case Bytecodes::_ladd: // fall through
322 case Bytecodes::_fadd: // fall through
323 case Bytecodes::_dadd: // fall through
324 case Bytecodes::_imul: // fall through
325 case Bytecodes::_lmul: // fall through
326 case Bytecodes::_fmul: // fall through
327 case Bytecodes::_dmul: return true;
328 default : return false;
329 }
330 }
331
332
333 bool ArithmeticOp::can_trap() const {
334 switch (op()) {
335 case Bytecodes::_idiv: // fall through
336 case Bytecodes::_ldiv: // fall through
337 case Bytecodes::_irem: // fall through
338 case Bytecodes::_lrem: return true;
339 default : return false;
340 }
341 }
342
343
344 // Implementation of LogicOp
345
346 bool LogicOp::is_commutative() const {
347 #ifdef ASSERT
348 switch (op()) {
349 case Bytecodes::_iand: // fall through
350 case Bytecodes::_land: // fall through
351 case Bytecodes::_ior : // fall through
352 case Bytecodes::_lor : // fall through
353 case Bytecodes::_ixor: // fall through
354 case Bytecodes::_lxor: break;
355 default : ShouldNotReachHere(); break;
356 }
357 #endif
358 // all LogicOps are commutative
359 return true;
360 }
361
362
363 // Implementation of IfOp
364
365 bool IfOp::is_commutative() const {
366 return cond() == eql || cond() == neq;
367 }
368
369
370 // Implementation of StateSplit
371
372 void StateSplit::substitute(BlockList& list, BlockBegin* old_block, BlockBegin* new_block) {
373 NOT_PRODUCT(bool assigned = false;)
374 for (int i = 0; i < list.length(); i++) {
375 BlockBegin** b = list.adr_at(i);
376 if (*b == old_block) {
377 *b = new_block;
378 NOT_PRODUCT(assigned = true;)
379 }
380 }
381 assert(assigned == true, "should have assigned at least once");
382 }
383
384
385 IRScope* StateSplit::scope() const {
386 return _state->scope();
387 }
388
389
390 void StateSplit::state_values_do(ValueVisitor* f) {
391 Instruction::state_values_do(f);
392 if (state() != NULL) state()->values_do(f);
393 }
394
395
396 void BlockBegin::state_values_do(ValueVisitor* f) {
397 StateSplit::state_values_do(f);
398
399 if (is_set(BlockBegin::exception_entry_flag)) {
400 for (int i = 0; i < number_of_exception_states(); i++) {
401 exception_state_at(i)->values_do(f);
402 }
403 }
404 }
405
406
407 // Implementation of Invoke
408
409
410 Invoke::Invoke(Bytecodes::Code code, ValueType* result_type, Value recv, Values* args,
411 int vtable_index, ciMethod* target, ValueStack* state_before)
412 : StateSplit(result_type, state_before)
413 , _code(code)
414 , _recv(recv)
415 , _args(args)
416 , _vtable_index(vtable_index)
417 , _target(target)
418 {
419 set_flag(TargetIsLoadedFlag, target->is_loaded());
420 set_flag(TargetIsFinalFlag, target_is_loaded() && target->is_final_method());
421 set_flag(TargetIsStrictfpFlag, target_is_loaded() && target->is_strict());
422
423 assert(args != NULL, "args must exist");
424 #ifdef ASSERT
425 AssertValues assert_value;
426 values_do(&assert_value);
427 #endif
428
429 // provide an initial guess of signature size.
430 _signature = new BasicTypeList(number_of_arguments() + (has_receiver() ? 1 : 0));
431 if (has_receiver()) {
432 _signature->append(as_BasicType(receiver()->type()));
433 }
434 for (int i = 0; i < number_of_arguments(); i++) {
435 ValueType* t = argument_at(i)->type();
436 BasicType bt = as_BasicType(t);
437 _signature->append(bt);
438 }
439 }
440
441
442 void Invoke::state_values_do(ValueVisitor* f) {
443 StateSplit::state_values_do(f);
444 if (state_before() != NULL) state_before()->values_do(f);
445 if (state() != NULL) state()->values_do(f);
446 }
447
448 ciType* Invoke::declared_type() const {
449 ciSignature* declared_signature = state()->scope()->method()->get_declared_signature_at_bci(state()->bci());
450 ciType *t = declared_signature->return_type();
451 assert(t->basic_type() != T_VOID, "need return value of void method?");
452 return t;
453 }
454
455 // Implementation of Contant
456 intx Constant::hash() const {
457 if (state_before() == NULL) {
458 switch (type()->tag()) {
459 case intTag:
460 return HASH2(name(), type()->as_IntConstant()->value());
461 case addressTag:
462 return HASH2(name(), type()->as_AddressConstant()->value());
463 case longTag:
464 {
465 jlong temp = type()->as_LongConstant()->value();
466 return HASH3(name(), high(temp), low(temp));
467 }
468 case floatTag:
469 return HASH2(name(), jint_cast(type()->as_FloatConstant()->value()));
470 case doubleTag:
471 {
472 jlong temp = jlong_cast(type()->as_DoubleConstant()->value());
473 return HASH3(name(), high(temp), low(temp));
474 }
475 case objectTag:
476 assert(type()->as_ObjectType()->is_loaded(), "can't handle unloaded values");
477 return HASH2(name(), type()->as_ObjectType()->constant_value());
478 case metaDataTag:
479 assert(type()->as_MetadataType()->is_loaded(), "can't handle unloaded values");
480 return HASH2(name(), type()->as_MetadataType()->constant_value());
481 default:
482 ShouldNotReachHere();
483 }
484 }
485 return 0;
486 }
487
488 bool Constant::is_equal(Value v) const {
489 if (v->as_Constant() == NULL) return false;
490
491 switch (type()->tag()) {
492 case intTag:
493 {
494 IntConstant* t1 = type()->as_IntConstant();
495 IntConstant* t2 = v->type()->as_IntConstant();
496 return (t1 != NULL && t2 != NULL &&
497 t1->value() == t2->value());
498 }
499 case longTag:
500 {
501 LongConstant* t1 = type()->as_LongConstant();
502 LongConstant* t2 = v->type()->as_LongConstant();
503 return (t1 != NULL && t2 != NULL &&
504 t1->value() == t2->value());
505 }
506 case floatTag:
507 {
508 FloatConstant* t1 = type()->as_FloatConstant();
509 FloatConstant* t2 = v->type()->as_FloatConstant();
510 return (t1 != NULL && t2 != NULL &&
511 jint_cast(t1->value()) == jint_cast(t2->value()));
512 }
513 case doubleTag:
514 {
515 DoubleConstant* t1 = type()->as_DoubleConstant();
516 DoubleConstant* t2 = v->type()->as_DoubleConstant();
517 return (t1 != NULL && t2 != NULL &&
518 jlong_cast(t1->value()) == jlong_cast(t2->value()));
519 }
520 case objectTag:
521 {
522 ObjectType* t1 = type()->as_ObjectType();
523 ObjectType* t2 = v->type()->as_ObjectType();
524 return (t1 != NULL && t2 != NULL &&
525 t1->is_loaded() && t2->is_loaded() &&
526 t1->constant_value() == t2->constant_value());
527 }
528 case metaDataTag:
529 {
530 MetadataType* t1 = type()->as_MetadataType();
531 MetadataType* t2 = v->type()->as_MetadataType();
532 return (t1 != NULL && t2 != NULL &&
533 t1->is_loaded() && t2->is_loaded() &&
534 t1->constant_value() == t2->constant_value());
535 }
536 default:
537 return false;
538 }
539 }
540
541 Constant::CompareResult Constant::compare(Instruction::Condition cond, Value right) const {
542 Constant* rc = right->as_Constant();
543 // other is not a constant
544 if (rc == NULL) return not_comparable;
545
546 ValueType* lt = type();
547 ValueType* rt = rc->type();
548 // different types
549 if (lt->base() != rt->base()) return not_comparable;
550 switch (lt->tag()) {
551 case intTag: {
552 int x = lt->as_IntConstant()->value();
553 int y = rt->as_IntConstant()->value();
554 switch (cond) {
555 case If::eql: return x == y ? cond_true : cond_false;
556 case If::neq: return x != y ? cond_true : cond_false;
557 case If::lss: return x < y ? cond_true : cond_false;
558 case If::leq: return x <= y ? cond_true : cond_false;
559 case If::gtr: return x > y ? cond_true : cond_false;
560 case If::geq: return x >= y ? cond_true : cond_false;
561 default : break;
562 }
563 break;
564 }
565 case longTag: {
566 jlong x = lt->as_LongConstant()->value();
567 jlong y = rt->as_LongConstant()->value();
568 switch (cond) {
569 case If::eql: return x == y ? cond_true : cond_false;
570 case If::neq: return x != y ? cond_true : cond_false;
571 case If::lss: return x < y ? cond_true : cond_false;
572 case If::leq: return x <= y ? cond_true : cond_false;
573 case If::gtr: return x > y ? cond_true : cond_false;
574 case If::geq: return x >= y ? cond_true : cond_false;
575 default : break;
576 }
577 break;
578 }
579 case objectTag: {
580 ciObject* xvalue = lt->as_ObjectType()->constant_value();
581 ciObject* yvalue = rt->as_ObjectType()->constant_value();
582 assert(xvalue != NULL && yvalue != NULL, "not constants");
583 if (xvalue->is_loaded() && yvalue->is_loaded()) {
584 switch (cond) {
585 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
586 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
587 default : break;
588 }
589 }
590 break;
591 }
592 case metaDataTag: {
593 ciMetadata* xvalue = lt->as_MetadataType()->constant_value();
594 ciMetadata* yvalue = rt->as_MetadataType()->constant_value();
595 assert(xvalue != NULL && yvalue != NULL, "not constants");
596 if (xvalue->is_loaded() && yvalue->is_loaded()) {
597 switch (cond) {
598 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
599 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
600 default : break;
601 }
602 }
603 break;
604 }
605 default:
606 break;
607 }
608 return not_comparable;
609 }
610
611
612 // Implementation of BlockBegin
613
614 void BlockBegin::set_end(BlockEnd* end) {
615 assert(end != NULL, "should not reset block end to NULL");
616 if (end == _end) {
617 return;
618 }
619 clear_end();
620
621 // Set the new end
622 _end = end;
623
624 _successors.clear();
625 // Now reset successors list based on BlockEnd
626 for (int i = 0; i < end->number_of_sux(); i++) {
627 BlockBegin* sux = end->sux_at(i);
628 _successors.append(sux);
629 sux->_predecessors.append(this);
630 }
631 _end->set_begin(this);
632 }
633
634
635 void BlockBegin::clear_end() {
636 // Must make the predecessors/successors match up with the
637 // BlockEnd's notion.
638 if (_end != NULL) {
639 // disconnect from the old end
640 _end->set_begin(NULL);
641
642 // disconnect this block from it's current successors
643 for (int i = 0; i < _successors.length(); i++) {
644 _successors.at(i)->remove_predecessor(this);
645 }
646 _end = NULL;
647 }
648 }
649
650
651 void BlockBegin::disconnect_edge(BlockBegin* from, BlockBegin* to) {
652 // disconnect any edges between from and to
653 #ifndef PRODUCT
654 if (PrintIR && Verbose) {
655 tty->print_cr("Disconnected edge B%d -> B%d", from->block_id(), to->block_id());
656 }
657 #endif
658 for (int s = 0; s < from->number_of_sux();) {
659 BlockBegin* sux = from->sux_at(s);
660 if (sux == to) {
661 int index = sux->_predecessors.find(from);
662 if (index >= 0) {
663 sux->_predecessors.remove_at(index);
664 }
665 from->_successors.remove_at(s);
666 } else {
667 s++;
668 }
669 }
670 }
671
672
673 void BlockBegin::disconnect_from_graph() {
674 // disconnect this block from all other blocks
675 for (int p = 0; p < number_of_preds(); p++) {
676 pred_at(p)->remove_successor(this);
677 }
678 for (int s = 0; s < number_of_sux(); s++) {
679 sux_at(s)->remove_predecessor(this);
680 }
681 }
682
683 void BlockBegin::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
684 // modify predecessors before substituting successors
685 for (int i = 0; i < number_of_sux(); i++) {
686 if (sux_at(i) == old_sux) {
687 // remove old predecessor before adding new predecessor
688 // otherwise there is a dead predecessor in the list
689 new_sux->remove_predecessor(old_sux);
690 new_sux->add_predecessor(this);
691 }
692 }
693 old_sux->remove_predecessor(this);
694 end()->substitute_sux(old_sux, new_sux);
695 }
696
697
698
699 // In general it is not possible to calculate a value for the field "depth_first_number"
700 // of the inserted block, without recomputing the values of the other blocks
701 // in the CFG. Therefore the value of "depth_first_number" in BlockBegin becomes meaningless.
702 BlockBegin* BlockBegin::insert_block_between(BlockBegin* sux) {
703 int bci = sux->bci();
704 // critical edge splitting may introduce a goto after a if and array
705 // bound check elimination may insert a predicate between the if and
706 // goto. The bci of the goto can't be the one of the if otherwise
707 // the state and bci are inconsistent and a deoptimization triggered
708 // by the predicate would lead to incorrect execution/a crash.
709 BlockBegin* new_sux = new BlockBegin(bci);
710
711 // mark this block (special treatment when block order is computed)
712 new_sux->set(critical_edge_split_flag);
713
714 // This goto is not a safepoint.
715 Goto* e = new Goto(sux, false);
716 new_sux->set_next(e, bci);
717 new_sux->set_end(e);
718 // setup states
719 ValueStack* s = end()->state();
720 new_sux->set_state(s->copy(s->kind(), bci));
721 e->set_state(s->copy(s->kind(), bci));
722 assert(new_sux->state()->locals_size() == s->locals_size(), "local size mismatch!");
723 assert(new_sux->state()->stack_size() == s->stack_size(), "stack size mismatch!");
724 assert(new_sux->state()->locks_size() == s->locks_size(), "locks size mismatch!");
725
726 // link predecessor to new block
727 end()->substitute_sux(sux, new_sux);
728
729 // The ordering needs to be the same, so remove the link that the
730 // set_end call above added and substitute the new_sux for this
731 // block.
732 sux->remove_predecessor(new_sux);
733
734 // the successor could be the target of a switch so it might have
735 // multiple copies of this predecessor, so substitute the new_sux
736 // for the first and delete the rest.
737 bool assigned = false;
738 BlockList& list = sux->_predecessors;
739 for (int i = 0; i < list.length(); i++) {
740 BlockBegin** b = list.adr_at(i);
741 if (*b == this) {
742 if (assigned) {
743 list.remove_at(i);
744 // reprocess this index
745 i--;
746 } else {
747 assigned = true;
748 *b = new_sux;
749 }
750 // link the new block back to it's predecessors.
751 new_sux->add_predecessor(this);
752 }
753 }
754 assert(assigned == true, "should have assigned at least once");
755 return new_sux;
756 }
757
758
759 void BlockBegin::remove_successor(BlockBegin* pred) {
760 int idx;
761 while ((idx = _successors.find(pred)) >= 0) {
762 _successors.remove_at(idx);
763 }
764 }
765
766
767 void BlockBegin::add_predecessor(BlockBegin* pred) {
768 _predecessors.append(pred);
769 }
770
771
772 void BlockBegin::remove_predecessor(BlockBegin* pred) {
773 int idx;
774 while ((idx = _predecessors.find(pred)) >= 0) {
775 _predecessors.remove_at(idx);
776 }
777 }
778
779
780 void BlockBegin::add_exception_handler(BlockBegin* b) {
781 assert(b != NULL && (b->is_set(exception_entry_flag)), "exception handler must exist");
782 // add only if not in the list already
783 if (!_exception_handlers.contains(b)) _exception_handlers.append(b);
784 }
785
786 int BlockBegin::add_exception_state(ValueStack* state) {
787 assert(is_set(exception_entry_flag), "only for xhandlers");
788 if (_exception_states == NULL) {
789 _exception_states = new ValueStackStack(4);
790 }
791 _exception_states->append(state);
792 return _exception_states->length() - 1;
793 }
794
795
796 void BlockBegin::iterate_preorder(boolArray& mark, BlockClosure* closure) {
797 if (!mark.at(block_id())) {
798 mark.at_put(block_id(), true);
799 closure->block_do(this);
800 BlockEnd* e = end(); // must do this after block_do because block_do may change it!
801 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_preorder(mark, closure); }
802 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_preorder(mark, closure); }
803 }
804 }
805
806
807 void BlockBegin::iterate_postorder(boolArray& mark, BlockClosure* closure) {
808 if (!mark.at(block_id())) {
809 mark.at_put(block_id(), true);
810 BlockEnd* e = end();
811 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_postorder(mark, closure); }
812 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_postorder(mark, closure); }
813 closure->block_do(this);
814 }
815 }
816
817
818 void BlockBegin::iterate_preorder(BlockClosure* closure) {
819 int mark_len = number_of_blocks();
820 boolArray mark(mark_len, mark_len, false);
821 iterate_preorder(mark, closure);
822 }
823
824
825 void BlockBegin::iterate_postorder(BlockClosure* closure) {
826 int mark_len = number_of_blocks();
827 boolArray mark(mark_len, mark_len, false);
828 iterate_postorder(mark, closure);
829 }
830
831
832 void BlockBegin::block_values_do(ValueVisitor* f) {
833 for (Instruction* n = this; n != NULL; n = n->next()) n->values_do(f);
834 }
835
836
837 #ifndef PRODUCT
838 #define TRACE_PHI(code) if (PrintPhiFunctions) { code; }
839 #else
840 #define TRACE_PHI(coce)
841 #endif
842
843
844 bool BlockBegin::try_merge(ValueStack* new_state) {
845 TRACE_PHI(tty->print_cr("********** try_merge for block B%d", block_id()));
846
847 // local variables used for state iteration
848 int index;
849 Value new_value, existing_value;
850
851 ValueStack* existing_state = state();
852 if (existing_state == NULL) {
853 TRACE_PHI(tty->print_cr("first call of try_merge for this block"));
854
855 if (is_set(BlockBegin::was_visited_flag)) {
856 // this actually happens for complicated jsr/ret structures
857 return false; // BAILOUT in caller
858 }
859
860 // copy state because it is altered
861 new_state = new_state->copy(ValueStack::BlockBeginState, bci());
862
863 // Use method liveness to invalidate dead locals
864 MethodLivenessResult liveness = new_state->scope()->method()->liveness_at_bci(bci());
865 if (liveness.is_valid()) {
866 assert((int)liveness.size() == new_state->locals_size(), "error in use of liveness");
867
868 for_each_local_value(new_state, index, new_value) {
869 if (!liveness.at(index) || new_value->type()->is_illegal()) {
870 new_state->invalidate_local(index);
871 TRACE_PHI(tty->print_cr("invalidating dead local %d", index));
872 }
873 }
874 }
875
876 if (is_set(BlockBegin::parser_loop_header_flag)) {
877 TRACE_PHI(tty->print_cr("loop header block, initializing phi functions"));
878
879 for_each_stack_value(new_state, index, new_value) {
880 new_state->setup_phi_for_stack(this, index, NULL, new_value);
881 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));
882 }
883
884 BitMap& requires_phi_function = new_state->scope()->requires_phi_function();
885
886 for_each_local_value(new_state, index, new_value) {
887 bool requires_phi = requires_phi_function.at(index) || (new_value->type()->is_double_word() && requires_phi_function.at(index + 1));
888 if (requires_phi || !SelectivePhiFunctions) {
889 new_state->setup_phi_for_local(this, index, NULL, new_value);
890 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));
891 }
892 }
893 }
894
895 // initialize state of block
896 set_state(new_state);
897
898 } else if (existing_state->is_same(new_state)) {
899 TRACE_PHI(tty->print_cr("exisiting state found"));
900
901 assert(existing_state->scope() == new_state->scope(), "not matching");
902 assert(existing_state->locals_size() == new_state->locals_size(), "not matching");
903 assert(existing_state->stack_size() == new_state->stack_size(), "not matching");
904
905 if (is_set(BlockBegin::was_visited_flag)) {
906 TRACE_PHI(tty->print_cr("loop header block, phis must be present"));
907
908 if (!is_set(BlockBegin::parser_loop_header_flag)) {
909 // this actually happens for complicated jsr/ret structures
910 return false; // BAILOUT in caller
911 }
912
913 for_each_local_value(existing_state, index, existing_value) {
914 Value new_value = new_state->local_at(index);
915 if (new_value == NULL || new_value->type()->tag() != existing_value->type()->tag()) {
916 Phi* existing_phi = existing_value->as_Phi();
917 if (existing_phi == NULL) {
918 return false; // BAILOUT in caller
919 }
920 // Invalidate the phi function here. This case is very rare except for
921 // JVMTI capability "can_access_local_variables".
922 // In really rare cases we will bail out in LIRGenerator::move_to_phi.
923 existing_phi->make_illegal();
924 existing_state->invalidate_local(index);
925 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
926 }
927 }
928
929 #ifdef ASSERT
930 // check that all necessary phi functions are present
931 for_each_stack_value(existing_state, index, existing_value) {
932 assert(existing_value->as_Phi() != NULL && existing_value->as_Phi()->block() == this, "phi function required");
933 }
934 for_each_local_value(existing_state, index, existing_value) {
935 assert(existing_value == new_state->local_at(index) || (existing_value->as_Phi() != NULL && existing_value->as_Phi()->as_Phi()->block() == this), "phi function required");
936 }
937 #endif
938
939 } else {
940 TRACE_PHI(tty->print_cr("creating phi functions on demand"));
941
942 // create necessary phi functions for stack
943 for_each_stack_value(existing_state, index, existing_value) {
944 Value new_value = new_state->stack_at(index);
945 Phi* existing_phi = existing_value->as_Phi();
946
947 if (new_value != existing_value && (existing_phi == NULL || existing_phi->block() != this)) {
948 existing_state->setup_phi_for_stack(this, index, existing_value, new_value);
949 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));
950 }
951 }
952
953 // create necessary phi functions for locals
954 for_each_local_value(existing_state, index, existing_value) {
955 Value new_value = new_state->local_at(index);
956 Phi* existing_phi = existing_value->as_Phi();
957
958 if (new_value == NULL || new_value->type()->tag() != existing_value->type()->tag()) {
959 existing_state->invalidate_local(index);
960 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
961 } else if (new_value != existing_value && (existing_phi == NULL || existing_phi->block() != this)) {
962 existing_state->setup_phi_for_local(this, index, existing_value, new_value);
963 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));
964 }
965 }
966 }
967
968 assert(existing_state->caller_state() == new_state->caller_state(), "caller states must be equal");
969
970 } else {
971 assert(false, "stack or locks not matching (invalid bytecodes)");
972 return false;
973 }
974
975 TRACE_PHI(tty->print_cr("********** try_merge for block B%d successful", block_id()));
976
977 return true;
978 }
979
980
981 #ifndef PRODUCT
982 void BlockBegin::print_block() {
983 InstructionPrinter ip;
984 print_block(ip, false);
985 }
986
987
988 void BlockBegin::print_block(InstructionPrinter& ip, bool live_only) {
989 ip.print_instr(this); tty->cr();
990 ip.print_stack(this->state()); tty->cr();
991 ip.print_inline_level(this);
992 ip.print_head();
993 for (Instruction* n = next(); n != NULL; n = n->next()) {
994 if (!live_only || n->is_pinned() || n->use_count() > 0) {
995 ip.print_line(n);
996 }
997 }
998 tty->cr();
999 }
1000 #endif // PRODUCT
1001
1002
1003 // Implementation of BlockList
1004
1005 void BlockList::iterate_forward (BlockClosure* closure) {
1006 const int l = length();
1007 for (int i = 0; i < l; i++) closure->block_do(at(i));
1008 }
1009
1010
1011 void BlockList::iterate_backward(BlockClosure* closure) {
1012 for (int i = length() - 1; i >= 0; i--) closure->block_do(at(i));
1013 }
1014
1015
1016 void BlockList::blocks_do(void f(BlockBegin*)) {
1017 for (int i = length() - 1; i >= 0; i--) f(at(i));
1018 }
1019
1020
1021 void BlockList::values_do(ValueVisitor* f) {
1022 for (int i = length() - 1; i >= 0; i--) at(i)->block_values_do(f);
1023 }
1024
1025
1026 #ifndef PRODUCT
1027 void BlockList::print(bool cfg_only, bool live_only) {
1028 InstructionPrinter ip;
1029 for (int i = 0; i < length(); i++) {
1030 BlockBegin* block = at(i);
1031 if (cfg_only) {
1032 ip.print_instr(block); tty->cr();
1033 } else {
1034 block->print_block(ip, live_only);
1035 }
1036 }
1037 }
1038 #endif // PRODUCT
1039
1040
1041 // Implementation of BlockEnd
1042
1043 void BlockEnd::set_begin(BlockBegin* begin) {
1044 BlockList* sux = NULL;
1045 if (begin != NULL) {
1046 sux = begin->successors();
1047 } else if (this->begin() != NULL) {
1048 // copy our sux list
1049 BlockList* sux = new BlockList(this->begin()->number_of_sux());
1050 for (int i = 0; i < this->begin()->number_of_sux(); i++) {
1051 sux->append(this->begin()->sux_at(i));
1052 }
1053 }
1054 _sux = sux;
1055 }
1056
1057
1058 void BlockEnd::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
1059 substitute(*_sux, old_sux, new_sux);
1060 }
1061
1062
1063 // Implementation of Phi
1064
1065 // Normal phi functions take their operands from the last instruction of the
1066 // predecessor. Special handling is needed for xhanlder entries because there
1067 // the state of arbitrary instructions are needed.
1068
1069 Value Phi::operand_at(int i) const {
1070 ValueStack* state;
1071 if (_block->is_set(BlockBegin::exception_entry_flag)) {
1072 state = _block->exception_state_at(i);
1073 } else {
1074 state = _block->pred_at(i)->end()->state();
1075 }
1076 assert(state != NULL, "");
1077
1078 if (is_local()) {
1079 return state->local_at(local_index());
1080 } else {
1081 return state->stack_at(stack_index());
1082 }
1083 }
1084
1085
1086 int Phi::operand_count() const {
1087 if (_block->is_set(BlockBegin::exception_entry_flag)) {
1088 return _block->number_of_exception_states();
1089 } else {
1090 return _block->number_of_preds();
1091 }
1092 }
1093
1094 #ifdef ASSERT
1095 // Constructor of Assert
1096 Assert::Assert(Value x, Condition cond, bool unordered_is_true, Value y) : Instruction(illegalType)
1097 , _x(x)
1098 , _cond(cond)
1099 , _y(y)
1100 {
1101 set_flag(UnorderedIsTrueFlag, unordered_is_true);
1102 assert(x->type()->tag() == y->type()->tag(), "types must match");
1103 pin();
1104
1105 stringStream strStream;
1106 Compilation::current()->method()->print_name(&strStream);
1107
1108 stringStream strStream1;
1109 InstructionPrinter ip1(1, &strStream1);
1110 ip1.print_instr(x);
1111
1112 stringStream strStream2;
1113 InstructionPrinter ip2(1, &strStream2);
1114 ip2.print_instr(y);
1115
1116 stringStream ss;
1117 ss.print("Assertion %s %s %s in method %s", strStream1.as_string(), ip2.cond_name(cond), strStream2.as_string(), strStream.as_string());
1118
1119 _message = ss.as_string();
1120 }
1121 #endif
1122
1123 void RangeCheckPredicate::check_state() {
1124 assert(state()->kind() != ValueStack::EmptyExceptionState && state()->kind() != ValueStack::ExceptionState, "will deopt with empty state");
1125 }
1126
1127 void ProfileInvoke::state_values_do(ValueVisitor* f) {
1128 if (state() != NULL) state()->values_do(f);
1129 }