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, bool never_null)
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 set_never_null(never_null);
433
434 assert(args != NULL, "args must exist");
435 #ifdef ASSERT
436 AssertValues assert_value;
437 values_do(&assert_value);
438 #endif
439
440 // provide an initial guess of signature size.
441 _signature = new BasicTypeList(number_of_arguments() + (has_receiver() ? 1 : 0));
442 if (has_receiver()) {
443 _signature->append(as_BasicType(receiver()->type()));
444 }
445 for (int i = 0; i < number_of_arguments(); i++) {
446 ValueType* t = argument_at(i)->type();
447 BasicType bt = as_BasicType(t);
448 _signature->append(bt);
449 }
450 }
451
452
453 void Invoke::state_values_do(ValueVisitor* f) {
454 StateSplit::state_values_do(f);
455 if (state_before() != NULL) state_before()->values_do(f);
456 if (state() != NULL) state()->values_do(f);
457 }
458
459 ciType* Invoke::declared_type() const {
460 ciSignature* declared_signature = state()->scope()->method()->get_declared_signature_at_bci(state()->bci());
461 ciType *t = declared_signature->return_type();
462 assert(t->basic_type() != T_VOID, "need return value of void method?");
463 return t;
464 }
465
466 // Implementation of Contant
467 intx Constant::hash() const {
468 if (state_before() == NULL) {
469 switch (type()->tag()) {
470 case intTag:
471 return HASH2(name(), type()->as_IntConstant()->value());
472 case addressTag:
473 return HASH2(name(), type()->as_AddressConstant()->value());
474 case longTag:
475 {
476 jlong temp = type()->as_LongConstant()->value();
477 return HASH3(name(), high(temp), low(temp));
478 }
479 case floatTag:
480 return HASH2(name(), jint_cast(type()->as_FloatConstant()->value()));
481 case doubleTag:
482 {
483 jlong temp = jlong_cast(type()->as_DoubleConstant()->value());
484 return HASH3(name(), high(temp), low(temp));
485 }
486 case objectTag:
487 assert(type()->as_ObjectType()->is_loaded(), "can't handle unloaded values");
488 return HASH2(name(), type()->as_ObjectType()->constant_value());
489 case metaDataTag:
490 assert(type()->as_MetadataType()->is_loaded(), "can't handle unloaded values");
491 return HASH2(name(), type()->as_MetadataType()->constant_value());
492 default:
493 ShouldNotReachHere();
494 }
495 }
496 return 0;
497 }
498
499 bool Constant::is_equal(Value v) const {
500 if (v->as_Constant() == NULL) return false;
501
502 switch (type()->tag()) {
503 case intTag:
504 {
505 IntConstant* t1 = type()->as_IntConstant();
506 IntConstant* t2 = v->type()->as_IntConstant();
507 return (t1 != NULL && t2 != NULL &&
508 t1->value() == t2->value());
509 }
510 case longTag:
511 {
512 LongConstant* t1 = type()->as_LongConstant();
513 LongConstant* t2 = v->type()->as_LongConstant();
514 return (t1 != NULL && t2 != NULL &&
515 t1->value() == t2->value());
516 }
517 case floatTag:
518 {
519 FloatConstant* t1 = type()->as_FloatConstant();
520 FloatConstant* t2 = v->type()->as_FloatConstant();
521 return (t1 != NULL && t2 != NULL &&
522 jint_cast(t1->value()) == jint_cast(t2->value()));
523 }
524 case doubleTag:
525 {
526 DoubleConstant* t1 = type()->as_DoubleConstant();
527 DoubleConstant* t2 = v->type()->as_DoubleConstant();
528 return (t1 != NULL && t2 != NULL &&
529 jlong_cast(t1->value()) == jlong_cast(t2->value()));
530 }
531 case objectTag:
532 {
533 ObjectType* t1 = type()->as_ObjectType();
534 ObjectType* t2 = v->type()->as_ObjectType();
535 return (t1 != NULL && t2 != NULL &&
536 t1->is_loaded() && t2->is_loaded() &&
537 t1->constant_value() == t2->constant_value());
538 }
539 case metaDataTag:
540 {
541 MetadataType* t1 = type()->as_MetadataType();
542 MetadataType* t2 = v->type()->as_MetadataType();
543 return (t1 != NULL && t2 != NULL &&
544 t1->is_loaded() && t2->is_loaded() &&
545 t1->constant_value() == t2->constant_value());
546 }
547 default:
548 return false;
549 }
550 }
551
552 Constant::CompareResult Constant::compare(Instruction::Condition cond, Value right) const {
553 Constant* rc = right->as_Constant();
554 // other is not a constant
555 if (rc == NULL) return not_comparable;
556
557 ValueType* lt = type();
558 ValueType* rt = rc->type();
559 // different types
560 if (lt->base() != rt->base()) return not_comparable;
561 switch (lt->tag()) {
562 case intTag: {
563 int x = lt->as_IntConstant()->value();
564 int y = rt->as_IntConstant()->value();
565 switch (cond) {
566 case If::eql: return x == y ? cond_true : cond_false;
567 case If::neq: return x != y ? cond_true : cond_false;
568 case If::lss: return x < y ? cond_true : cond_false;
569 case If::leq: return x <= y ? cond_true : cond_false;
570 case If::gtr: return x > y ? cond_true : cond_false;
571 case If::geq: return x >= y ? cond_true : cond_false;
572 default : break;
573 }
574 break;
575 }
576 case longTag: {
577 jlong x = lt->as_LongConstant()->value();
578 jlong y = rt->as_LongConstant()->value();
579 switch (cond) {
580 case If::eql: return x == y ? cond_true : cond_false;
581 case If::neq: return x != y ? cond_true : cond_false;
582 case If::lss: return x < y ? cond_true : cond_false;
583 case If::leq: return x <= y ? cond_true : cond_false;
584 case If::gtr: return x > y ? cond_true : cond_false;
585 case If::geq: return x >= y ? cond_true : cond_false;
586 default : break;
587 }
588 break;
589 }
590 case objectTag: {
591 ciObject* xvalue = lt->as_ObjectType()->constant_value();
592 ciObject* yvalue = rt->as_ObjectType()->constant_value();
593 assert(xvalue != NULL && yvalue != NULL, "not constants");
594 if (xvalue->is_loaded() && yvalue->is_loaded()) {
595 switch (cond) {
596 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
597 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
598 default : break;
599 }
600 }
601 break;
602 }
603 case metaDataTag: {
604 ciMetadata* xvalue = lt->as_MetadataType()->constant_value();
605 ciMetadata* yvalue = rt->as_MetadataType()->constant_value();
606 assert(xvalue != NULL && yvalue != NULL, "not constants");
607 if (xvalue->is_loaded() && yvalue->is_loaded()) {
608 switch (cond) {
609 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
610 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
611 default : break;
612 }
613 }
614 break;
615 }
616 default:
617 break;
618 }
619 return not_comparable;
620 }
621
622
623 // Implementation of BlockBegin
624
625 void BlockBegin::set_end(BlockEnd* end) {
626 assert(end != NULL, "should not reset block end to NULL");
627 if (end == _end) {
628 return;
629 }
630 clear_end();
631
632 // Set the new end
633 _end = end;
634
635 _successors.clear();
636 // Now reset successors list based on BlockEnd
637 for (int i = 0; i < end->number_of_sux(); i++) {
638 BlockBegin* sux = end->sux_at(i);
639 _successors.append(sux);
640 sux->_predecessors.append(this);
641 }
642 _end->set_begin(this);
643 }
644
645
646 void BlockBegin::clear_end() {
647 // Must make the predecessors/successors match up with the
648 // BlockEnd's notion.
649 if (_end != NULL) {
650 // disconnect from the old end
651 _end->set_begin(NULL);
652
653 // disconnect this block from it's current successors
654 for (int i = 0; i < _successors.length(); i++) {
655 _successors.at(i)->remove_predecessor(this);
656 }
657 _end = NULL;
658 }
659 }
660
661
662 void BlockBegin::disconnect_edge(BlockBegin* from, BlockBegin* to) {
663 // disconnect any edges between from and to
664 #ifndef PRODUCT
665 if (PrintIR && Verbose) {
666 tty->print_cr("Disconnected edge B%d -> B%d", from->block_id(), to->block_id());
667 }
668 #endif
669 for (int s = 0; s < from->number_of_sux();) {
670 BlockBegin* sux = from->sux_at(s);
671 if (sux == to) {
672 int index = sux->_predecessors.find(from);
673 if (index >= 0) {
674 sux->_predecessors.remove_at(index);
675 }
676 from->_successors.remove_at(s);
677 } else {
678 s++;
679 }
680 }
681 }
682
683
684 void BlockBegin::disconnect_from_graph() {
685 // disconnect this block from all other blocks
686 for (int p = 0; p < number_of_preds(); p++) {
687 pred_at(p)->remove_successor(this);
688 }
689 for (int s = 0; s < number_of_sux(); s++) {
690 sux_at(s)->remove_predecessor(this);
691 }
692 }
693
694 void BlockBegin::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
695 // modify predecessors before substituting successors
696 for (int i = 0; i < number_of_sux(); i++) {
697 if (sux_at(i) == old_sux) {
698 // remove old predecessor before adding new predecessor
699 // otherwise there is a dead predecessor in the list
700 new_sux->remove_predecessor(old_sux);
701 new_sux->add_predecessor(this);
702 }
703 }
704 old_sux->remove_predecessor(this);
705 end()->substitute_sux(old_sux, new_sux);
706 }
707
708
709
710 // In general it is not possible to calculate a value for the field "depth_first_number"
711 // of the inserted block, without recomputing the values of the other blocks
712 // in the CFG. Therefore the value of "depth_first_number" in BlockBegin becomes meaningless.
713 BlockBegin* BlockBegin::insert_block_between(BlockBegin* sux) {
714 int bci = sux->bci();
715 // critical edge splitting may introduce a goto after a if and array
716 // bound check elimination may insert a predicate between the if and
717 // goto. The bci of the goto can't be the one of the if otherwise
718 // the state and bci are inconsistent and a deoptimization triggered
719 // by the predicate would lead to incorrect execution/a crash.
720 BlockBegin* new_sux = new BlockBegin(bci);
721
722 // mark this block (special treatment when block order is computed)
723 new_sux->set(critical_edge_split_flag);
724
725 // This goto is not a safepoint.
726 Goto* e = new Goto(sux, false);
727 new_sux->set_next(e, bci);
728 new_sux->set_end(e);
729 // setup states
730 ValueStack* s = end()->state();
731 new_sux->set_state(s->copy(s->kind(), bci));
732 e->set_state(s->copy(s->kind(), bci));
733 assert(new_sux->state()->locals_size() == s->locals_size(), "local size mismatch!");
734 assert(new_sux->state()->stack_size() == s->stack_size(), "stack size mismatch!");
735 assert(new_sux->state()->locks_size() == s->locks_size(), "locks size mismatch!");
736
737 // link predecessor to new block
738 end()->substitute_sux(sux, new_sux);
739
740 // The ordering needs to be the same, so remove the link that the
741 // set_end call above added and substitute the new_sux for this
742 // block.
743 sux->remove_predecessor(new_sux);
744
745 // the successor could be the target of a switch so it might have
746 // multiple copies of this predecessor, so substitute the new_sux
747 // for the first and delete the rest.
748 bool assigned = false;
749 BlockList& list = sux->_predecessors;
750 for (int i = 0; i < list.length(); i++) {
751 BlockBegin** b = list.adr_at(i);
752 if (*b == this) {
753 if (assigned) {
754 list.remove_at(i);
755 // reprocess this index
756 i--;
757 } else {
758 assigned = true;
759 *b = new_sux;
760 }
761 // link the new block back to it's predecessors.
762 new_sux->add_predecessor(this);
763 }
764 }
765 assert(assigned == true, "should have assigned at least once");
766 return new_sux;
767 }
768
769
770 void BlockBegin::remove_successor(BlockBegin* pred) {
771 int idx;
772 while ((idx = _successors.find(pred)) >= 0) {
773 _successors.remove_at(idx);
774 }
775 }
776
777
778 void BlockBegin::add_predecessor(BlockBegin* pred) {
779 _predecessors.append(pred);
780 }
781
782
783 void BlockBegin::remove_predecessor(BlockBegin* pred) {
784 int idx;
785 while ((idx = _predecessors.find(pred)) >= 0) {
786 _predecessors.remove_at(idx);
787 }
788 }
789
790
791 void BlockBegin::add_exception_handler(BlockBegin* b) {
792 assert(b != NULL && (b->is_set(exception_entry_flag)), "exception handler must exist");
793 // add only if not in the list already
794 if (!_exception_handlers.contains(b)) _exception_handlers.append(b);
795 }
796
797 int BlockBegin::add_exception_state(ValueStack* state) {
798 assert(is_set(exception_entry_flag), "only for xhandlers");
799 if (_exception_states == NULL) {
800 _exception_states = new ValueStackStack(4);
801 }
802 _exception_states->append(state);
803 return _exception_states->length() - 1;
804 }
805
806
807 void BlockBegin::iterate_preorder(boolArray& mark, BlockClosure* closure) {
808 if (!mark.at(block_id())) {
809 mark.at_put(block_id(), true);
810 closure->block_do(this);
811 BlockEnd* e = end(); // must do this after block_do because block_do may change it!
812 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_preorder(mark, closure); }
813 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_preorder(mark, closure); }
814 }
815 }
816
817
818 void BlockBegin::iterate_postorder(boolArray& mark, BlockClosure* closure) {
819 if (!mark.at(block_id())) {
820 mark.at_put(block_id(), true);
821 BlockEnd* e = end();
822 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_postorder(mark, closure); }
823 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_postorder(mark, closure); }
824 closure->block_do(this);
825 }
826 }
827
828
829 void BlockBegin::iterate_preorder(BlockClosure* closure) {
830 int mark_len = number_of_blocks();
831 boolArray mark(mark_len, mark_len, false);
832 iterate_preorder(mark, closure);
833 }
834
835
836 void BlockBegin::iterate_postorder(BlockClosure* closure) {
837 int mark_len = number_of_blocks();
838 boolArray mark(mark_len, mark_len, false);
839 iterate_postorder(mark, closure);
840 }
841
842
843 void BlockBegin::block_values_do(ValueVisitor* f) {
844 for (Instruction* n = this; n != NULL; n = n->next()) n->values_do(f);
845 }
846
847
848 #ifndef PRODUCT
849 #define TRACE_PHI(code) if (PrintPhiFunctions) { code; }
850 #else
851 #define TRACE_PHI(coce)
852 #endif
853
854
855 bool BlockBegin::try_merge(ValueStack* new_state) {
856 TRACE_PHI(tty->print_cr("********** try_merge for block B%d", block_id()));
857
858 // local variables used for state iteration
859 int index;
860 Value new_value, existing_value;
861
862 ValueStack* existing_state = state();
863 if (existing_state == NULL) {
864 TRACE_PHI(tty->print_cr("first call of try_merge for this block"));
865
866 if (is_set(BlockBegin::was_visited_flag)) {
867 // this actually happens for complicated jsr/ret structures
868 return false; // BAILOUT in caller
869 }
870
871 // copy state because it is altered
872 new_state = new_state->copy(ValueStack::BlockBeginState, bci());
873
874 // Use method liveness to invalidate dead locals
875 MethodLivenessResult liveness = new_state->scope()->method()->liveness_at_bci(bci());
876 if (liveness.is_valid()) {
877 assert((int)liveness.size() == new_state->locals_size(), "error in use of liveness");
878
879 for_each_local_value(new_state, index, new_value) {
880 if (!liveness.at(index) || new_value->type()->is_illegal()) {
881 new_state->invalidate_local(index);
882 TRACE_PHI(tty->print_cr("invalidating dead local %d", index));
883 }
884 }
885 }
886
887 if (is_set(BlockBegin::parser_loop_header_flag)) {
888 TRACE_PHI(tty->print_cr("loop header block, initializing phi functions"));
889
890 for_each_stack_value(new_state, index, new_value) {
891 new_state->setup_phi_for_stack(this, index, NULL, new_value);
892 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));
893 }
894
895 BitMap& requires_phi_function = new_state->scope()->requires_phi_function();
896
897 for_each_local_value(new_state, index, new_value) {
898 bool requires_phi = requires_phi_function.at(index) || (new_value->type()->is_double_word() && requires_phi_function.at(index + 1));
899 if (requires_phi || !SelectivePhiFunctions) {
900 new_state->setup_phi_for_local(this, index, NULL, new_value);
901 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));
902 }
903 }
904 }
905
906 // initialize state of block
907 set_state(new_state);
908
909 } else if (existing_state->is_same(new_state)) {
910 TRACE_PHI(tty->print_cr("exisiting state found"));
911
912 assert(existing_state->scope() == new_state->scope(), "not matching");
913 assert(existing_state->locals_size() == new_state->locals_size(), "not matching");
914 assert(existing_state->stack_size() == new_state->stack_size(), "not matching");
915
916 if (is_set(BlockBegin::was_visited_flag)) {
917 TRACE_PHI(tty->print_cr("loop header block, phis must be present"));
918
919 if (!is_set(BlockBegin::parser_loop_header_flag)) {
920 // this actually happens for complicated jsr/ret structures
921 return false; // BAILOUT in caller
922 }
923
924 for_each_local_value(existing_state, index, existing_value) {
925 Value new_value = new_state->local_at(index);
926 if (new_value == NULL || new_value->type()->tag() != existing_value->type()->tag()) {
927 Phi* existing_phi = existing_value->as_Phi();
928 if (existing_phi == NULL) {
929 return false; // BAILOUT in caller
930 }
931 // Invalidate the phi function here. This case is very rare except for
932 // JVMTI capability "can_access_local_variables".
933 // In really rare cases we will bail out in LIRGenerator::move_to_phi.
934 existing_phi->make_illegal();
935 existing_state->invalidate_local(index);
936 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
937 }
938 }
939
940 #ifdef ASSERT
941 // check that all necessary phi functions are present
942 for_each_stack_value(existing_state, index, existing_value) {
943 assert(existing_value->as_Phi() != NULL && existing_value->as_Phi()->block() == this, "phi function required");
944 }
945 for_each_local_value(existing_state, index, existing_value) {
946 assert(existing_value == new_state->local_at(index) || (existing_value->as_Phi() != NULL && existing_value->as_Phi()->as_Phi()->block() == this), "phi function required");
947 }
948 #endif
949
950 } else {
951 TRACE_PHI(tty->print_cr("creating phi functions on demand"));
952
953 // create necessary phi functions for stack
954 for_each_stack_value(existing_state, index, existing_value) {
955 Value new_value = new_state->stack_at(index);
956 Phi* existing_phi = existing_value->as_Phi();
957
958 if (new_value != existing_value && (existing_phi == NULL || existing_phi->block() != this)) {
959 existing_state->setup_phi_for_stack(this, index, existing_value, new_value);
960 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));
961 }
962 }
963
964 // create necessary phi functions for locals
965 for_each_local_value(existing_state, index, existing_value) {
966 Value new_value = new_state->local_at(index);
967 Phi* existing_phi = existing_value->as_Phi();
968
969 if (new_value == NULL || new_value->type()->tag() != existing_value->type()->tag()) {
970 existing_state->invalidate_local(index);
971 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
972 } else if (new_value != existing_value && (existing_phi == NULL || existing_phi->block() != this)) {
973 existing_state->setup_phi_for_local(this, index, existing_value, new_value);
974 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));
975 }
976 }
977 }
978
979 assert(existing_state->caller_state() == new_state->caller_state(), "caller states must be equal");
980
981 } else {
982 assert(false, "stack or locks not matching (invalid bytecodes)");
983 return false;
984 }
985
986 TRACE_PHI(tty->print_cr("********** try_merge for block B%d successful", block_id()));
987
988 return true;
989 }
990
991
992 #ifndef PRODUCT
993 void BlockBegin::print_block() {
994 InstructionPrinter ip;
995 print_block(ip, false);
996 }
997
998
999 void BlockBegin::print_block(InstructionPrinter& ip, bool live_only) {
1000 ip.print_instr(this); tty->cr();
1001 ip.print_stack(this->state()); tty->cr();
1002 ip.print_inline_level(this);
1003 ip.print_head();
1004 for (Instruction* n = next(); n != NULL; n = n->next()) {
1005 if (!live_only || n->is_pinned() || n->use_count() > 0) {
1006 ip.print_line(n);
1007 }
1008 }
1009 tty->cr();
1010 }
1011 #endif // PRODUCT
1012
1013
1014 // Implementation of BlockList
1015
1016 void BlockList::iterate_forward (BlockClosure* closure) {
1017 const int l = length();
1018 for (int i = 0; i < l; i++) closure->block_do(at(i));
1019 }
1020
1021
1022 void BlockList::iterate_backward(BlockClosure* closure) {
1023 for (int i = length() - 1; i >= 0; i--) closure->block_do(at(i));
1024 }
1025
1026
1027 void BlockList::blocks_do(void f(BlockBegin*)) {
1028 for (int i = length() - 1; i >= 0; i--) f(at(i));
1029 }
1030
1031
1032 void BlockList::values_do(ValueVisitor* f) {
1033 for (int i = length() - 1; i >= 0; i--) at(i)->block_values_do(f);
1034 }
1035
1036
1037 #ifndef PRODUCT
1038 void BlockList::print(bool cfg_only, bool live_only) {
1039 InstructionPrinter ip;
1040 for (int i = 0; i < length(); i++) {
1041 BlockBegin* block = at(i);
1042 if (cfg_only) {
1043 ip.print_instr(block); tty->cr();
1044 } else {
1045 block->print_block(ip, live_only);
1046 }
1047 }
1048 }
1049 #endif // PRODUCT
1050
1051
1052 // Implementation of BlockEnd
1053
1054 void BlockEnd::set_begin(BlockBegin* begin) {
1055 BlockList* sux = NULL;
1056 if (begin != NULL) {
1057 sux = begin->successors();
1058 } else if (this->begin() != NULL) {
1059 // copy our sux list
1060 BlockList* sux = new BlockList(this->begin()->number_of_sux());
1061 for (int i = 0; i < this->begin()->number_of_sux(); i++) {
1062 sux->append(this->begin()->sux_at(i));
1063 }
1064 }
1065 _sux = sux;
1066 }
1067
1068
1069 void BlockEnd::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
1070 substitute(*_sux, old_sux, new_sux);
1071 }
1072
1073
1074 // Implementation of Phi
1075
1076 // Normal phi functions take their operands from the last instruction of the
1077 // predecessor. Special handling is needed for xhanlder entries because there
1078 // the state of arbitrary instructions are needed.
1079
1080 Value Phi::operand_at(int i) const {
1081 ValueStack* state;
1082 if (_block->is_set(BlockBegin::exception_entry_flag)) {
1083 state = _block->exception_state_at(i);
1084 } else {
1085 state = _block->pred_at(i)->end()->state();
1086 }
1087 assert(state != NULL, "");
1088
1089 if (is_local()) {
1090 return state->local_at(local_index());
1091 } else {
1092 return state->stack_at(stack_index());
1093 }
1094 }
1095
1096
1097 int Phi::operand_count() const {
1098 if (_block->is_set(BlockBegin::exception_entry_flag)) {
1099 return _block->number_of_exception_states();
1100 } else {
1101 return _block->number_of_preds();
1102 }
1103 }
1104
1105 #ifdef ASSERT
1106 // Constructor of Assert
1107 Assert::Assert(Value x, Condition cond, bool unordered_is_true, Value y) : Instruction(illegalType)
1108 , _x(x)
1109 , _cond(cond)
1110 , _y(y)
1111 {
1112 set_flag(UnorderedIsTrueFlag, unordered_is_true);
1113 assert(x->type()->tag() == y->type()->tag(), "types must match");
1114 pin();
1115
1116 stringStream strStream;
1117 Compilation::current()->method()->print_name(&strStream);
1118
1119 stringStream strStream1;
1120 InstructionPrinter ip1(1, &strStream1);
1121 ip1.print_instr(x);
1122
1123 stringStream strStream2;
1124 InstructionPrinter ip2(1, &strStream2);
1125 ip2.print_instr(y);
1126
1127 stringStream ss;
1128 ss.print("Assertion %s %s %s in method %s", strStream1.as_string(), ip2.cond_name(cond), strStream2.as_string(), strStream.as_string());
1129
1130 _message = ss.as_string();
1131 }
1132 #endif
1133
1134 void RangeCheckPredicate::check_state() {
1135 assert(state()->kind() != ValueStack::EmptyExceptionState && state()->kind() != ValueStack::ExceptionState, "will deopt with empty state");
1136 }
1137
1138 void ProfileInvoke::state_values_do(ValueVisitor* f) {
1139 if (state() != NULL) state()->values_do(f);
1140 }