1 /*
2 * Copyright (c) 1999, 2019, 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 bool StoreIndexed::is_exact_flattened_array_store() const {
261 if (array()->is_loaded_flattened_array() && value()->as_Constant() == NULL) {
262 ciKlass* element_klass = array()->declared_type()->as_value_array_klass()->element_klass();
263 ciKlass* actual_klass = value()->declared_type()->as_klass();
264 if (element_klass == actual_klass) {
265 return true;
266 }
267 }
268 return false;
269 }
270
271 ciType* LoadField::declared_type() const {
272 return field()->type();
273 }
274
275
276 ciType* NewTypeArray::exact_type() const {
277 return ciTypeArrayKlass::make(elt_type());
278 }
279
280 ciType* NewObjectArray::exact_type() const {
281 ciKlass* element_klass = klass();
282 if (element_klass->is_valuetype()) {
283 return ciValueArrayKlass::make(element_klass);
284 } else {
285 return ciObjArrayKlass::make(element_klass);
286 }
287 }
288
289 ciType* NewMultiArray::exact_type() const {
290 return _klass;
291 }
292
293 ciType* NewArray::declared_type() const {
294 return exact_type();
295 }
296
297 ciType* NewInstance::exact_type() const {
298 return klass();
299 }
300
301 ciType* NewInstance::declared_type() const {
302 return exact_type();
303 }
304
305 Value NewValueTypeInstance::depends_on() {
306 if (_depends_on != this) {
307 if (_depends_on->as_NewValueTypeInstance() != NULL) {
308 return _depends_on->as_NewValueTypeInstance()->depends_on();
309 }
310 }
311 return _depends_on;
312 }
313
314 ciType* NewValueTypeInstance::exact_type() const {
315 return klass();
316 }
317
318 ciType* NewValueTypeInstance::declared_type() const {
319 return exact_type();
320 }
321
322 ciType* CheckCast::declared_type() const {
323 return klass();
324 }
325
326 // Implementation of ArithmeticOp
327
328 bool ArithmeticOp::is_commutative() const {
329 switch (op()) {
330 case Bytecodes::_iadd: // fall through
331 case Bytecodes::_ladd: // fall through
332 case Bytecodes::_fadd: // fall through
333 case Bytecodes::_dadd: // fall through
334 case Bytecodes::_imul: // fall through
335 case Bytecodes::_lmul: // fall through
336 case Bytecodes::_fmul: // fall through
337 case Bytecodes::_dmul: return true;
338 default : return false;
339 }
340 }
341
342
343 bool ArithmeticOp::can_trap() const {
344 switch (op()) {
345 case Bytecodes::_idiv: // fall through
346 case Bytecodes::_ldiv: // fall through
347 case Bytecodes::_irem: // fall through
348 case Bytecodes::_lrem: return true;
349 default : return false;
350 }
351 }
352
353
354 // Implementation of LogicOp
355
356 bool LogicOp::is_commutative() const {
357 #ifdef ASSERT
358 switch (op()) {
359 case Bytecodes::_iand: // fall through
360 case Bytecodes::_land: // fall through
361 case Bytecodes::_ior : // fall through
362 case Bytecodes::_lor : // fall through
363 case Bytecodes::_ixor: // fall through
364 case Bytecodes::_lxor: break;
365 default : ShouldNotReachHere(); break;
366 }
367 #endif
368 // all LogicOps are commutative
369 return true;
370 }
371
372
373 // Implementation of IfOp
374
375 bool IfOp::is_commutative() const {
376 return cond() == eql || cond() == neq;
377 }
378
379
380 // Implementation of StateSplit
381
382 void StateSplit::substitute(BlockList& list, BlockBegin* old_block, BlockBegin* new_block) {
383 NOT_PRODUCT(bool assigned = false;)
384 for (int i = 0; i < list.length(); i++) {
385 BlockBegin** b = list.adr_at(i);
386 if (*b == old_block) {
387 *b = new_block;
388 NOT_PRODUCT(assigned = true;)
389 }
390 }
391 assert(assigned == true, "should have assigned at least once");
392 }
393
394
395 IRScope* StateSplit::scope() const {
396 return _state->scope();
397 }
398
399
400 void StateSplit::state_values_do(ValueVisitor* f) {
401 Instruction::state_values_do(f);
402 if (state() != NULL) state()->values_do(f);
403 }
404
405
406 void BlockBegin::state_values_do(ValueVisitor* f) {
407 StateSplit::state_values_do(f);
408
409 if (is_set(BlockBegin::exception_entry_flag)) {
410 for (int i = 0; i < number_of_exception_states(); i++) {
411 exception_state_at(i)->values_do(f);
412 }
413 }
414 }
415
416
417 // Implementation of Invoke
418
419
420 Invoke::Invoke(Bytecodes::Code code, ValueType* result_type, Value recv, Values* args,
421 int vtable_index, ciMethod* target, ValueStack* state_before)
422 : StateSplit(result_type, state_before)
423 , _code(code)
424 , _recv(recv)
425 , _args(args)
426 , _vtable_index(vtable_index)
427 , _target(target)
428 {
429 set_flag(TargetIsLoadedFlag, target->is_loaded());
430 set_flag(TargetIsFinalFlag, target_is_loaded() && target->is_final_method());
431 set_flag(TargetIsStrictfpFlag, target_is_loaded() && target->is_strict());
432
433 assert(args != NULL, "args must exist");
434 #ifdef ASSERT
435 AssertValues assert_value;
436 values_do(&assert_value);
437 #endif
438
439 // provide an initial guess of signature size.
440 _signature = new BasicTypeList(number_of_arguments() + (has_receiver() ? 1 : 0));
441 if (has_receiver()) {
442 _signature->append(as_BasicType(receiver()->type()));
443 }
444 for (int i = 0; i < number_of_arguments(); i++) {
445 ValueType* t = argument_at(i)->type();
446 BasicType bt = as_BasicType(t);
447 _signature->append(bt);
448 }
449 }
450
451
452 void Invoke::state_values_do(ValueVisitor* f) {
453 StateSplit::state_values_do(f);
454 if (state_before() != NULL) state_before()->values_do(f);
455 if (state() != NULL) state()->values_do(f);
456 }
457
458 ciType* Invoke::declared_type() const {
459 ciSignature* declared_signature = state()->scope()->method()->get_declared_signature_at_bci(state()->bci());
460 ciType *t = declared_signature->return_type();
461 assert(t->basic_type() != T_VOID, "need return value of void method?");
462 return t;
463 }
464
465 // Implementation of Contant
466 intx Constant::hash() const {
467 if (state_before() == NULL) {
468 switch (type()->tag()) {
469 case intTag:
470 return HASH2(name(), type()->as_IntConstant()->value());
471 case addressTag:
472 return HASH2(name(), type()->as_AddressConstant()->value());
473 case longTag:
474 {
475 jlong temp = type()->as_LongConstant()->value();
476 return HASH3(name(), high(temp), low(temp));
477 }
478 case floatTag:
479 return HASH2(name(), jint_cast(type()->as_FloatConstant()->value()));
480 case doubleTag:
481 {
482 jlong temp = jlong_cast(type()->as_DoubleConstant()->value());
483 return HASH3(name(), high(temp), low(temp));
484 }
485 case objectTag:
486 assert(type()->as_ObjectType()->is_loaded(), "can't handle unloaded values");
487 return HASH2(name(), type()->as_ObjectType()->constant_value());
488 case metaDataTag:
489 assert(type()->as_MetadataType()->is_loaded(), "can't handle unloaded values");
490 return HASH2(name(), type()->as_MetadataType()->constant_value());
491 default:
492 ShouldNotReachHere();
493 }
494 }
495 return 0;
496 }
497
498 bool Constant::is_equal(Value v) const {
499 if (v->as_Constant() == NULL) return false;
500
501 switch (type()->tag()) {
502 case intTag:
503 {
504 IntConstant* t1 = type()->as_IntConstant();
505 IntConstant* t2 = v->type()->as_IntConstant();
506 return (t1 != NULL && t2 != NULL &&
507 t1->value() == t2->value());
508 }
509 case longTag:
510 {
511 LongConstant* t1 = type()->as_LongConstant();
512 LongConstant* t2 = v->type()->as_LongConstant();
513 return (t1 != NULL && t2 != NULL &&
514 t1->value() == t2->value());
515 }
516 case floatTag:
517 {
518 FloatConstant* t1 = type()->as_FloatConstant();
519 FloatConstant* t2 = v->type()->as_FloatConstant();
520 return (t1 != NULL && t2 != NULL &&
521 jint_cast(t1->value()) == jint_cast(t2->value()));
522 }
523 case doubleTag:
524 {
525 DoubleConstant* t1 = type()->as_DoubleConstant();
526 DoubleConstant* t2 = v->type()->as_DoubleConstant();
527 return (t1 != NULL && t2 != NULL &&
528 jlong_cast(t1->value()) == jlong_cast(t2->value()));
529 }
530 case objectTag:
531 {
532 ObjectType* t1 = type()->as_ObjectType();
533 ObjectType* t2 = v->type()->as_ObjectType();
534 return (t1 != NULL && t2 != NULL &&
535 t1->is_loaded() && t2->is_loaded() &&
536 t1->constant_value() == t2->constant_value());
537 }
538 case metaDataTag:
539 {
540 MetadataType* t1 = type()->as_MetadataType();
541 MetadataType* t2 = v->type()->as_MetadataType();
542 return (t1 != NULL && t2 != NULL &&
543 t1->is_loaded() && t2->is_loaded() &&
544 t1->constant_value() == t2->constant_value());
545 }
546 default:
547 return false;
548 }
549 }
550
551 Constant::CompareResult Constant::compare(Instruction::Condition cond, Value right) const {
552 Constant* rc = right->as_Constant();
553 // other is not a constant
554 if (rc == NULL) return not_comparable;
555
556 ValueType* lt = type();
557 ValueType* rt = rc->type();
558 // different types
559 if (lt->base() != rt->base()) return not_comparable;
560 switch (lt->tag()) {
561 case intTag: {
562 int x = lt->as_IntConstant()->value();
563 int y = rt->as_IntConstant()->value();
564 switch (cond) {
565 case If::eql: return x == y ? cond_true : cond_false;
566 case If::neq: return x != y ? cond_true : cond_false;
567 case If::lss: return x < y ? cond_true : cond_false;
568 case If::leq: return x <= y ? cond_true : cond_false;
569 case If::gtr: return x > y ? cond_true : cond_false;
570 case If::geq: return x >= y ? cond_true : cond_false;
571 default : break;
572 }
573 break;
574 }
575 case longTag: {
576 jlong x = lt->as_LongConstant()->value();
577 jlong y = rt->as_LongConstant()->value();
578 switch (cond) {
579 case If::eql: return x == y ? cond_true : cond_false;
580 case If::neq: return x != y ? cond_true : cond_false;
581 case If::lss: return x < y ? cond_true : cond_false;
582 case If::leq: return x <= y ? cond_true : cond_false;
583 case If::gtr: return x > y ? cond_true : cond_false;
584 case If::geq: return x >= y ? cond_true : cond_false;
585 default : break;
586 }
587 break;
588 }
589 case objectTag: {
590 ciObject* xvalue = lt->as_ObjectType()->constant_value();
591 ciObject* yvalue = rt->as_ObjectType()->constant_value();
592 assert(xvalue != NULL && yvalue != NULL, "not constants");
593 if (xvalue->is_loaded() && yvalue->is_loaded()) {
594 switch (cond) {
595 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
596 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
597 default : break;
598 }
599 }
600 break;
601 }
602 case metaDataTag: {
603 ciMetadata* xvalue = lt->as_MetadataType()->constant_value();
604 ciMetadata* yvalue = rt->as_MetadataType()->constant_value();
605 assert(xvalue != NULL && yvalue != NULL, "not constants");
606 if (xvalue->is_loaded() && yvalue->is_loaded()) {
607 switch (cond) {
608 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
609 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
610 default : break;
611 }
612 }
613 break;
614 }
615 default:
616 break;
617 }
618 return not_comparable;
619 }
620
621
622 // Implementation of BlockBegin
623
624 void BlockBegin::set_end(BlockEnd* end) {
625 assert(end != NULL, "should not reset block end to NULL");
626 if (end == _end) {
627 return;
628 }
629 clear_end();
630
631 // Set the new end
632 _end = end;
633
634 _successors.clear();
635 // Now reset successors list based on BlockEnd
636 for (int i = 0; i < end->number_of_sux(); i++) {
637 BlockBegin* sux = end->sux_at(i);
638 _successors.append(sux);
639 sux->_predecessors.append(this);
640 }
641 _end->set_begin(this);
642 }
643
644
645 void BlockBegin::clear_end() {
646 // Must make the predecessors/successors match up with the
647 // BlockEnd's notion.
648 if (_end != NULL) {
649 // disconnect from the old end
650 _end->set_begin(NULL);
651
652 // disconnect this block from it's current successors
653 for (int i = 0; i < _successors.length(); i++) {
654 _successors.at(i)->remove_predecessor(this);
655 }
656 _end = NULL;
657 }
658 }
659
660
661 void BlockBegin::disconnect_edge(BlockBegin* from, BlockBegin* to) {
662 // disconnect any edges between from and to
663 #ifndef PRODUCT
664 if (PrintIR && Verbose) {
665 tty->print_cr("Disconnected edge B%d -> B%d", from->block_id(), to->block_id());
666 }
667 #endif
668 for (int s = 0; s < from->number_of_sux();) {
669 BlockBegin* sux = from->sux_at(s);
670 if (sux == to) {
671 int index = sux->_predecessors.find(from);
672 if (index >= 0) {
673 sux->_predecessors.remove_at(index);
674 }
675 from->_successors.remove_at(s);
676 } else {
677 s++;
678 }
679 }
680 }
681
682
683 void BlockBegin::disconnect_from_graph() {
684 // disconnect this block from all other blocks
685 for (int p = 0; p < number_of_preds(); p++) {
686 pred_at(p)->remove_successor(this);
687 }
688 for (int s = 0; s < number_of_sux(); s++) {
689 sux_at(s)->remove_predecessor(this);
690 }
691 }
692
693 void BlockBegin::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
694 // modify predecessors before substituting successors
695 for (int i = 0; i < number_of_sux(); i++) {
696 if (sux_at(i) == old_sux) {
697 // remove old predecessor before adding new predecessor
698 // otherwise there is a dead predecessor in the list
699 new_sux->remove_predecessor(old_sux);
700 new_sux->add_predecessor(this);
701 }
702 }
703 old_sux->remove_predecessor(this);
704 end()->substitute_sux(old_sux, new_sux);
705 }
706
707
708
709 // In general it is not possible to calculate a value for the field "depth_first_number"
710 // of the inserted block, without recomputing the values of the other blocks
711 // in the CFG. Therefore the value of "depth_first_number" in BlockBegin becomes meaningless.
712 BlockBegin* BlockBegin::insert_block_between(BlockBegin* sux) {
713 int bci = sux->bci();
714 // critical edge splitting may introduce a goto after a if and array
715 // bound check elimination may insert a predicate between the if and
716 // goto. The bci of the goto can't be the one of the if otherwise
717 // the state and bci are inconsistent and a deoptimization triggered
718 // by the predicate would lead to incorrect execution/a crash.
719 BlockBegin* new_sux = new BlockBegin(bci);
720
721 // mark this block (special treatment when block order is computed)
722 new_sux->set(critical_edge_split_flag);
723
724 // This goto is not a safepoint.
725 Goto* e = new Goto(sux, false);
726 new_sux->set_next(e, bci);
727 new_sux->set_end(e);
728 // setup states
729 ValueStack* s = end()->state();
730 new_sux->set_state(s->copy(s->kind(), bci));
731 e->set_state(s->copy(s->kind(), bci));
732 assert(new_sux->state()->locals_size() == s->locals_size(), "local size mismatch!");
733 assert(new_sux->state()->stack_size() == s->stack_size(), "stack size mismatch!");
734 assert(new_sux->state()->locks_size() == s->locks_size(), "locks size mismatch!");
735
736 // link predecessor to new block
737 end()->substitute_sux(sux, new_sux);
738
739 // The ordering needs to be the same, so remove the link that the
740 // set_end call above added and substitute the new_sux for this
741 // block.
742 sux->remove_predecessor(new_sux);
743
744 // the successor could be the target of a switch so it might have
745 // multiple copies of this predecessor, so substitute the new_sux
746 // for the first and delete the rest.
747 bool assigned = false;
748 BlockList& list = sux->_predecessors;
749 for (int i = 0; i < list.length(); i++) {
750 BlockBegin** b = list.adr_at(i);
751 if (*b == this) {
752 if (assigned) {
753 list.remove_at(i);
754 // reprocess this index
755 i--;
756 } else {
757 assigned = true;
758 *b = new_sux;
759 }
760 // link the new block back to it's predecessors.
761 new_sux->add_predecessor(this);
762 }
763 }
764 assert(assigned == true, "should have assigned at least once");
765 return new_sux;
766 }
767
768
769 void BlockBegin::remove_successor(BlockBegin* pred) {
770 int idx;
771 while ((idx = _successors.find(pred)) >= 0) {
772 _successors.remove_at(idx);
773 }
774 }
775
776
777 void BlockBegin::add_predecessor(BlockBegin* pred) {
778 _predecessors.append(pred);
779 }
780
781
782 void BlockBegin::remove_predecessor(BlockBegin* pred) {
783 int idx;
784 while ((idx = _predecessors.find(pred)) >= 0) {
785 _predecessors.remove_at(idx);
786 }
787 }
788
789
790 void BlockBegin::add_exception_handler(BlockBegin* b) {
791 assert(b != NULL && (b->is_set(exception_entry_flag)), "exception handler must exist");
792 // add only if not in the list already
793 if (!_exception_handlers.contains(b)) _exception_handlers.append(b);
794 }
795
796 int BlockBegin::add_exception_state(ValueStack* state) {
797 assert(is_set(exception_entry_flag), "only for xhandlers");
798 if (_exception_states == NULL) {
799 _exception_states = new ValueStackStack(4);
800 }
801 _exception_states->append(state);
802 return _exception_states->length() - 1;
803 }
804
805
806 void BlockBegin::iterate_preorder(boolArray& mark, BlockClosure* closure) {
807 if (!mark.at(block_id())) {
808 mark.at_put(block_id(), true);
809 closure->block_do(this);
810 BlockEnd* e = end(); // must do this after block_do because block_do may change it!
811 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_preorder(mark, closure); }
812 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_preorder(mark, closure); }
813 }
814 }
815
816
817 void BlockBegin::iterate_postorder(boolArray& mark, BlockClosure* closure) {
818 if (!mark.at(block_id())) {
819 mark.at_put(block_id(), true);
820 BlockEnd* e = end();
821 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_postorder(mark, closure); }
822 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_postorder(mark, closure); }
823 closure->block_do(this);
824 }
825 }
826
827
828 void BlockBegin::iterate_preorder(BlockClosure* closure) {
829 int mark_len = number_of_blocks();
830 boolArray mark(mark_len, mark_len, false);
831 iterate_preorder(mark, closure);
832 }
833
834
835 void BlockBegin::iterate_postorder(BlockClosure* closure) {
836 int mark_len = number_of_blocks();
837 boolArray mark(mark_len, mark_len, false);
838 iterate_postorder(mark, closure);
839 }
840
841
842 void BlockBegin::block_values_do(ValueVisitor* f) {
843 for (Instruction* n = this; n != NULL; n = n->next()) n->values_do(f);
844 }
845
846
847 #ifndef PRODUCT
848 #define TRACE_PHI(code) if (PrintPhiFunctions) { code; }
849 #else
850 #define TRACE_PHI(coce)
851 #endif
852
853
854 bool BlockBegin::try_merge(ValueStack* new_state) {
855 TRACE_PHI(tty->print_cr("********** try_merge for block B%d", block_id()));
856
857 // local variables used for state iteration
858 int index;
859 Value new_value, existing_value;
860
861 ValueStack* existing_state = state();
862 if (existing_state == NULL) {
863 TRACE_PHI(tty->print_cr("first call of try_merge for this block"));
864
865 if (is_set(BlockBegin::was_visited_flag)) {
866 // this actually happens for complicated jsr/ret structures
867 return false; // BAILOUT in caller
868 }
869
870 // copy state because it is altered
871 new_state = new_state->copy(ValueStack::BlockBeginState, bci());
872
873 // Use method liveness to invalidate dead locals
874 MethodLivenessResult liveness = new_state->scope()->method()->liveness_at_bci(bci());
875 if (liveness.is_valid()) {
876 assert((int)liveness.size() == new_state->locals_size(), "error in use of liveness");
877
878 for_each_local_value(new_state, index, new_value) {
879 if (!liveness.at(index) || new_value->type()->is_illegal()) {
880 new_state->invalidate_local(index);
881 TRACE_PHI(tty->print_cr("invalidating dead local %d", index));
882 }
883 }
884 }
885
886 if (is_set(BlockBegin::parser_loop_header_flag)) {
887 TRACE_PHI(tty->print_cr("loop header block, initializing phi functions"));
888
889 for_each_stack_value(new_state, index, new_value) {
890 new_state->setup_phi_for_stack(this, index, NULL, new_value);
891 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));
892 }
893
894 BitMap& requires_phi_function = new_state->scope()->requires_phi_function();
895
896 for_each_local_value(new_state, index, new_value) {
897 bool requires_phi = requires_phi_function.at(index) || (new_value->type()->is_double_word() && requires_phi_function.at(index + 1));
898 if (requires_phi || !SelectivePhiFunctions) {
899 new_state->setup_phi_for_local(this, index, NULL, new_value);
900 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));
901 }
902 }
903 }
904
905 // initialize state of block
906 set_state(new_state);
907
908 } else if (existing_state->is_same(new_state)) {
909 TRACE_PHI(tty->print_cr("exisiting state found"));
910
911 assert(existing_state->scope() == new_state->scope(), "not matching");
912 assert(existing_state->locals_size() == new_state->locals_size(), "not matching");
913 assert(existing_state->stack_size() == new_state->stack_size(), "not matching");
914
915 if (is_set(BlockBegin::was_visited_flag)) {
916 TRACE_PHI(tty->print_cr("loop header block, phis must be present"));
917
918 if (!is_set(BlockBegin::parser_loop_header_flag)) {
919 // this actually happens for complicated jsr/ret structures
920 return false; // BAILOUT in caller
921 }
922
923 for_each_local_value(existing_state, index, existing_value) {
924 Value new_value = new_state->local_at(index);
925 if (new_value == NULL || new_value->type()->tag() != existing_value->type()->tag()) {
926 Phi* existing_phi = existing_value->as_Phi();
927 if (existing_phi == NULL) {
928 return false; // BAILOUT in caller
929 }
930 // Invalidate the phi function here. This case is very rare except for
931 // JVMTI capability "can_access_local_variables".
932 // In really rare cases we will bail out in LIRGenerator::move_to_phi.
933 existing_phi->make_illegal();
934 existing_state->invalidate_local(index);
935 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
936 }
937 }
938
939 #ifdef ASSERT
940 // check that all necessary phi functions are present
941 for_each_stack_value(existing_state, index, existing_value) {
942 assert(existing_value->as_Phi() != NULL && existing_value->as_Phi()->block() == this, "phi function required");
943 }
944 for_each_local_value(existing_state, index, existing_value) {
945 assert(existing_value == new_state->local_at(index) || (existing_value->as_Phi() != NULL && existing_value->as_Phi()->as_Phi()->block() == this), "phi function required");
946 }
947 #endif
948
949 } else {
950 TRACE_PHI(tty->print_cr("creating phi functions on demand"));
951
952 // create necessary phi functions for stack
953 for_each_stack_value(existing_state, index, existing_value) {
954 Value new_value = new_state->stack_at(index);
955 Phi* existing_phi = existing_value->as_Phi();
956
957 if (new_value != existing_value && (existing_phi == NULL || existing_phi->block() != this)) {
958 existing_state->setup_phi_for_stack(this, index, existing_value, new_value);
959 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));
960 }
961 }
962
963 // create necessary phi functions for locals
964 for_each_local_value(existing_state, index, existing_value) {
965 Value new_value = new_state->local_at(index);
966 Phi* existing_phi = existing_value->as_Phi();
967
968 if (new_value == NULL || new_value->type()->tag() != existing_value->type()->tag()) {
969 existing_state->invalidate_local(index);
970 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
971 } else if (new_value != existing_value && (existing_phi == NULL || existing_phi->block() != this)) {
972 existing_state->setup_phi_for_local(this, index, existing_value, new_value);
973 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));
974 }
975 }
976 }
977
978 assert(existing_state->caller_state() == new_state->caller_state(), "caller states must be equal");
979
980 } else {
981 assert(false, "stack or locks not matching (invalid bytecodes)");
982 return false;
983 }
984
985 TRACE_PHI(tty->print_cr("********** try_merge for block B%d successful", block_id()));
986
987 return true;
988 }
989
990
991 #ifndef PRODUCT
992 void BlockBegin::print_block() {
993 InstructionPrinter ip;
994 print_block(ip, false);
995 }
996
997
998 void BlockBegin::print_block(InstructionPrinter& ip, bool live_only) {
999 ip.print_instr(this); tty->cr();
1000 ip.print_stack(this->state()); tty->cr();
1001 ip.print_inline_level(this);
1002 ip.print_head();
1003 for (Instruction* n = next(); n != NULL; n = n->next()) {
1004 if (!live_only || n->is_pinned() || n->use_count() > 0) {
1005 ip.print_line(n);
1006 }
1007 }
1008 tty->cr();
1009 }
1010 #endif // PRODUCT
1011
1012
1013 // Implementation of BlockList
1014
1015 void BlockList::iterate_forward (BlockClosure* closure) {
1016 const int l = length();
1017 for (int i = 0; i < l; i++) closure->block_do(at(i));
1018 }
1019
1020
1021 void BlockList::iterate_backward(BlockClosure* closure) {
1022 for (int i = length() - 1; i >= 0; i--) closure->block_do(at(i));
1023 }
1024
1025
1026 void BlockList::blocks_do(void f(BlockBegin*)) {
1027 for (int i = length() - 1; i >= 0; i--) f(at(i));
1028 }
1029
1030
1031 void BlockList::values_do(ValueVisitor* f) {
1032 for (int i = length() - 1; i >= 0; i--) at(i)->block_values_do(f);
1033 }
1034
1035
1036 #ifndef PRODUCT
1037 void BlockList::print(bool cfg_only, bool live_only) {
1038 InstructionPrinter ip;
1039 for (int i = 0; i < length(); i++) {
1040 BlockBegin* block = at(i);
1041 if (cfg_only) {
1042 ip.print_instr(block); tty->cr();
1043 } else {
1044 block->print_block(ip, live_only);
1045 }
1046 }
1047 }
1048 #endif // PRODUCT
1049
1050
1051 // Implementation of BlockEnd
1052
1053 void BlockEnd::set_begin(BlockBegin* begin) {
1054 BlockList* sux = NULL;
1055 if (begin != NULL) {
1056 sux = begin->successors();
1057 } else if (this->begin() != NULL) {
1058 // copy our sux list
1059 BlockList* sux = new BlockList(this->begin()->number_of_sux());
1060 for (int i = 0; i < this->begin()->number_of_sux(); i++) {
1061 sux->append(this->begin()->sux_at(i));
1062 }
1063 }
1064 _sux = sux;
1065 }
1066
1067
1068 void BlockEnd::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
1069 substitute(*_sux, old_sux, new_sux);
1070 }
1071
1072
1073 // Implementation of Phi
1074
1075 // Normal phi functions take their operands from the last instruction of the
1076 // predecessor. Special handling is needed for xhanlder entries because there
1077 // the state of arbitrary instructions are needed.
1078
1079 Value Phi::operand_at(int i) const {
1080 ValueStack* state;
1081 if (_block->is_set(BlockBegin::exception_entry_flag)) {
1082 state = _block->exception_state_at(i);
1083 } else {
1084 state = _block->pred_at(i)->end()->state();
1085 }
1086 assert(state != NULL, "");
1087
1088 if (is_local()) {
1089 return state->local_at(local_index());
1090 } else {
1091 return state->stack_at(stack_index());
1092 }
1093 }
1094
1095
1096 int Phi::operand_count() const {
1097 if (_block->is_set(BlockBegin::exception_entry_flag)) {
1098 return _block->number_of_exception_states();
1099 } else {
1100 return _block->number_of_preds();
1101 }
1102 }
1103
1104 #ifdef ASSERT
1105 // Constructor of Assert
1106 Assert::Assert(Value x, Condition cond, bool unordered_is_true, Value y) : Instruction(illegalType)
1107 , _x(x)
1108 , _cond(cond)
1109 , _y(y)
1110 {
1111 set_flag(UnorderedIsTrueFlag, unordered_is_true);
1112 assert(x->type()->tag() == y->type()->tag(), "types must match");
1113 pin();
1114
1115 stringStream strStream;
1116 Compilation::current()->method()->print_name(&strStream);
1117
1118 stringStream strStream1;
1119 InstructionPrinter ip1(1, &strStream1);
1120 ip1.print_instr(x);
1121
1122 stringStream strStream2;
1123 InstructionPrinter ip2(1, &strStream2);
1124 ip2.print_instr(y);
1125
1126 stringStream ss;
1127 ss.print("Assertion %s %s %s in method %s", strStream1.as_string(), ip2.cond_name(cond), strStream2.as_string(), strStream.as_string());
1128
1129 _message = ss.as_string();
1130 }
1131 #endif
1132
1133 void RangeCheckPredicate::check_state() {
1134 assert(state()->kind() != ValueStack::EmptyExceptionState && state()->kind() != ValueStack::ExceptionState, "will deopt with empty state");
1135 }
1136
1137 void ProfileInvoke::state_values_do(ValueVisitor* f) {
1138 if (state() != NULL) state()->values_do(f);
1139 }