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 ciKlass* Instruction::as_loaded_klass_or_null() const {
118 ciType* type = declared_type();
119 if (type != NULL && type->is_klass()) {
120 ciKlass* klass = type->as_klass();
121 if (klass->is_loaded()) {
122 return klass;
123 }
124 }
125 return NULL;
126 }
127
128 // FIXME -- this is used by ValueStack::merge_types only. We should remove this function
129 // and use a better way for handling phi nodes.
130 bool Instruction::is_flattened_array() const {
131 if (ValueArrayFlatten) {
132 ciType* type = declared_type();
133 if (type != NULL && type->is_value_array_klass()) {
134 ciValueKlass* element_klass = type->as_value_array_klass()->element_klass()->as_value_klass();
135 assert(element_klass->is_loaded(), "ciValueKlasses are always loaded");
136 if (element_klass->flatten_array()) {
137 return true;
138 }
139 }
140 }
141
142 return false;
143 }
144
145 bool Instruction::is_loaded_flattened_array() const {
146 if (ValueArrayFlatten) {
147 ciType* type = declared_type();
148 if (type != NULL && type->is_value_array_klass()) {
149 ciValueArrayKlass* vak = type->as_value_array_klass();
150 ArrayStorageProperties props = vak->storage_properties();
151 return (!props.is_empty() && props.is_null_free() && props.is_flattened());
152 }
153 }
154
155 return false;
156 }
157
158 bool Instruction::maybe_flattened_array() {
159 if (ValueArrayFlatten) {
160 ciType* type = declared_type();
161 if (type != NULL) {
162 if (type->is_obj_array_klass()) {
163 // Check for array covariance. One of the following declared types may be a flattened array:
164 ciKlass* element_klass = type->as_obj_array_klass()->element_klass();
165 if (!element_klass->is_loaded() ||
166 element_klass->is_java_lang_Object() || // (ValueType[] <: Object[])
167 element_klass->is_interface() || // (ValueType[] <: <any interface>[])
168 (element_klass->is_valuetype() && element_klass->as_value_klass()->flatten_array())) { // (ValueType[] <: ValueType?[])
169 // We will add a runtime check for flat-ness.
170 return true;
171 }
172 } else if (type->is_klass() && type->as_klass()->is_java_lang_Object()) {
173 // This can happen as a parameter to System.arraycopy()
174 return true;
175 }
176 } else {
177 // Type info gets lost during Phi merging (Phi, IfOp, etc), but we might be storing into a
178 // flattened array, so we should do a runtime check.
179 return true;
180 }
181 }
182
183 return false;
184 }
185
186 bool Instruction::maybe_null_free_array() {
187 ciType* type = declared_type();
188 if (type != NULL) {
189 if (type->is_obj_array_klass()) {
190 // Check for array covariance. One of the following declared types may be a null-free array:
191 ciKlass* element_klass = type->as_obj_array_klass()->element_klass();
192 if (!element_klass->is_loaded() ||
193 element_klass->is_java_lang_Object() || // (ValueType[] <: Object[])
194 element_klass->is_interface() || // (ValueType[] <: <any interface>[])
195 element_klass->is_valuetype()) { // (ValueType[] <: ValueType?[])
196 // We will add a runtime check for flat-ness.
197 return true;
198 }
199 }
200 } else {
201 // Type info gets lost during Phi merging (Phi, IfOp, etc), but we might be storing into a
202 // flattened array, so we should do a runtime check.
203 return true;
204 }
205
206 return false;
207 }
208
209 #ifndef PRODUCT
210 void Instruction::check_state(ValueStack* state) {
211 if (state != NULL) {
212 state->verify();
213 }
214 }
215
216
217 void Instruction::print() {
218 InstructionPrinter ip;
219 print(ip);
220 }
221
222
223 void Instruction::print_line() {
224 InstructionPrinter ip;
225 ip.print_line(this);
226 }
227
228
229 void Instruction::print(InstructionPrinter& ip) {
230 ip.print_head();
231 ip.print_line(this);
232 tty->cr();
233 }
234 #endif // PRODUCT
235
236
237 // perform constant and interval tests on index value
238 bool AccessIndexed::compute_needs_range_check() {
239 if (length()) {
240 Constant* clength = length()->as_Constant();
241 Constant* cindex = index()->as_Constant();
242 if (clength && cindex) {
243 IntConstant* l = clength->type()->as_IntConstant();
244 IntConstant* i = cindex->type()->as_IntConstant();
245 if (l && i && i->value() < l->value() && i->value() >= 0) {
246 return false;
247 }
248 }
249 }
250
251 if (!this->check_flag(NeedsRangeCheckFlag)) {
252 return false;
253 }
254
255 return true;
256 }
257
258
259 ciType* Constant::exact_type() const {
260 if (type()->is_object() && type()->as_ObjectType()->is_loaded()) {
261 return type()->as_ObjectType()->exact_type();
262 }
263 return NULL;
264 }
265
266 ciType* LoadIndexed::exact_type() const {
267 ciType* array_type = array()->exact_type();
268 if (array_type != NULL) {
269 assert(array_type->is_array_klass(), "what else?");
270 ciArrayKlass* ak = (ciArrayKlass*)array_type;
271
272 if (ak->element_type()->is_instance_klass()) {
273 ciInstanceKlass* ik = (ciInstanceKlass*)ak->element_type();
274 if (ik->is_loaded() && ik->is_final()) {
275 return ik;
276 }
277 }
278 }
279 return Instruction::exact_type();
280 }
281
282
283 ciType* LoadIndexed::declared_type() const {
284 ciType* array_type = array()->declared_type();
285 if (array_type == NULL || !array_type->is_loaded()) {
286 return NULL;
287 }
288 assert(array_type->is_array_klass(), "what else?");
289 ciArrayKlass* ak = (ciArrayKlass*)array_type;
290 return ak->element_type();
291 }
292
293 bool StoreIndexed::is_exact_flattened_array_store() const {
294 if (array()->is_loaded_flattened_array() && value()->as_Constant() == NULL) {
295 ciKlass* element_klass = array()->declared_type()->as_value_array_klass()->element_klass();
296 ciKlass* actual_klass = value()->declared_type()->as_klass();
297 if (element_klass == actual_klass) {
298 return true;
299 } else {
300 // This can happen with inlining:
301 // void test45_inline(Object[] oa, Object o, int index) { oa[index] = o; }
302 // void test45(MyValue1[] va, int index, MyValue2 v) { test45_inline(va, v, index); }
303 return false;
304 }
305 }
306 return false;
307 }
308
309 ciType* LoadField::declared_type() const {
310 return field()->type();
311 }
312
313
314 ciType* NewTypeArray::exact_type() const {
315 return ciTypeArrayKlass::make(elt_type());
316 }
317
318 ciType* NewObjectArray::exact_type() const {
319 ciKlass* element_klass = klass();
320 if (is_never_null() && element_klass->is_valuetype()) {
321 return ciValueArrayKlass::make(element_klass);
322 } else {
323 return ciObjArrayKlass::make(element_klass);
324 }
325 }
326
327 ciType* NewMultiArray::exact_type() const {
328 return _klass;
329 }
330
331 ciType* NewArray::declared_type() const {
332 return exact_type();
333 }
334
335 ciType* NewInstance::exact_type() const {
336 return klass();
337 }
338
339 ciType* NewInstance::declared_type() const {
340 return exact_type();
341 }
342
343 Value NewValueTypeInstance::depends_on() {
344 if (_depends_on != this) {
345 if (_depends_on->as_NewValueTypeInstance() != NULL) {
346 return _depends_on->as_NewValueTypeInstance()->depends_on();
347 }
348 }
349 return _depends_on;
350 }
351
352 ciType* NewValueTypeInstance::exact_type() const {
353 return klass();
354 }
355
356 ciType* NewValueTypeInstance::declared_type() const {
357 return exact_type();
358 }
359
360 ciType* CheckCast::declared_type() const {
361 return klass();
362 }
363
364 // Implementation of ArithmeticOp
365
366 bool ArithmeticOp::is_commutative() const {
367 switch (op()) {
368 case Bytecodes::_iadd: // fall through
369 case Bytecodes::_ladd: // fall through
370 case Bytecodes::_fadd: // fall through
371 case Bytecodes::_dadd: // fall through
372 case Bytecodes::_imul: // fall through
373 case Bytecodes::_lmul: // fall through
374 case Bytecodes::_fmul: // fall through
375 case Bytecodes::_dmul: return true;
376 default : return false;
377 }
378 }
379
380
381 bool ArithmeticOp::can_trap() const {
382 switch (op()) {
383 case Bytecodes::_idiv: // fall through
384 case Bytecodes::_ldiv: // fall through
385 case Bytecodes::_irem: // fall through
386 case Bytecodes::_lrem: return true;
387 default : return false;
388 }
389 }
390
391
392 // Implementation of LogicOp
393
394 bool LogicOp::is_commutative() const {
395 #ifdef ASSERT
396 switch (op()) {
397 case Bytecodes::_iand: // fall through
398 case Bytecodes::_land: // fall through
399 case Bytecodes::_ior : // fall through
400 case Bytecodes::_lor : // fall through
401 case Bytecodes::_ixor: // fall through
402 case Bytecodes::_lxor: break;
403 default : ShouldNotReachHere(); break;
404 }
405 #endif
406 // all LogicOps are commutative
407 return true;
408 }
409
410
411 // Implementation of IfOp
412
413 bool IfOp::is_commutative() const {
414 return cond() == eql || cond() == neq;
415 }
416
417
418 // Implementation of StateSplit
419
420 void StateSplit::substitute(BlockList& list, BlockBegin* old_block, BlockBegin* new_block) {
421 NOT_PRODUCT(bool assigned = false;)
422 for (int i = 0; i < list.length(); i++) {
423 BlockBegin** b = list.adr_at(i);
424 if (*b == old_block) {
425 *b = new_block;
426 NOT_PRODUCT(assigned = true;)
427 }
428 }
429 assert(assigned == true, "should have assigned at least once");
430 }
431
432
433 IRScope* StateSplit::scope() const {
434 return _state->scope();
435 }
436
437
438 void StateSplit::state_values_do(ValueVisitor* f) {
439 Instruction::state_values_do(f);
440 if (state() != NULL) state()->values_do(f);
441 }
442
443
444 void BlockBegin::state_values_do(ValueVisitor* f) {
445 StateSplit::state_values_do(f);
446
447 if (is_set(BlockBegin::exception_entry_flag)) {
448 for (int i = 0; i < number_of_exception_states(); i++) {
449 exception_state_at(i)->values_do(f);
450 }
451 }
452 }
453
454
455 // Implementation of Invoke
456
457
458 Invoke::Invoke(Bytecodes::Code code, ValueType* result_type, Value recv, Values* args,
459 int vtable_index, ciMethod* target, ValueStack* state_before, bool never_null)
460 : StateSplit(result_type, state_before)
461 , _code(code)
462 , _recv(recv)
463 , _args(args)
464 , _vtable_index(vtable_index)
465 , _target(target)
466 {
467 set_flag(TargetIsLoadedFlag, target->is_loaded());
468 set_flag(TargetIsFinalFlag, target_is_loaded() && target->is_final_method());
469 set_flag(TargetIsStrictfpFlag, target_is_loaded() && target->is_strict());
470 set_never_null(never_null);
471
472 assert(args != NULL, "args must exist");
473 #ifdef ASSERT
474 AssertValues assert_value;
475 values_do(&assert_value);
476 #endif
477
478 // provide an initial guess of signature size.
479 _signature = new BasicTypeList(number_of_arguments() + (has_receiver() ? 1 : 0));
480 if (has_receiver()) {
481 _signature->append(as_BasicType(receiver()->type()));
482 }
483 for (int i = 0; i < number_of_arguments(); i++) {
484 ValueType* t = argument_at(i)->type();
485 BasicType bt = as_BasicType(t);
486 _signature->append(bt);
487 }
488 }
489
490
491 void Invoke::state_values_do(ValueVisitor* f) {
492 StateSplit::state_values_do(f);
493 if (state_before() != NULL) state_before()->values_do(f);
494 if (state() != NULL) state()->values_do(f);
495 }
496
497 ciType* Invoke::declared_type() const {
498 ciSignature* declared_signature = state()->scope()->method()->get_declared_signature_at_bci(state()->bci());
499 ciType *t = declared_signature->return_type();
500 assert(t->basic_type() != T_VOID, "need return value of void method?");
501 return t;
502 }
503
504 // Implementation of Contant
505 intx Constant::hash() const {
506 if (state_before() == NULL) {
507 switch (type()->tag()) {
508 case intTag:
509 return HASH2(name(), type()->as_IntConstant()->value());
510 case addressTag:
511 return HASH2(name(), type()->as_AddressConstant()->value());
512 case longTag:
513 {
514 jlong temp = type()->as_LongConstant()->value();
515 return HASH3(name(), high(temp), low(temp));
516 }
517 case floatTag:
518 return HASH2(name(), jint_cast(type()->as_FloatConstant()->value()));
519 case doubleTag:
520 {
521 jlong temp = jlong_cast(type()->as_DoubleConstant()->value());
522 return HASH3(name(), high(temp), low(temp));
523 }
524 case objectTag:
525 assert(type()->as_ObjectType()->is_loaded(), "can't handle unloaded values");
526 return HASH2(name(), type()->as_ObjectType()->constant_value());
527 case metaDataTag:
528 assert(type()->as_MetadataType()->is_loaded(), "can't handle unloaded values");
529 return HASH2(name(), type()->as_MetadataType()->constant_value());
530 default:
531 ShouldNotReachHere();
532 }
533 }
534 return 0;
535 }
536
537 bool Constant::is_equal(Value v) const {
538 if (v->as_Constant() == NULL) return false;
539
540 switch (type()->tag()) {
541 case intTag:
542 {
543 IntConstant* t1 = type()->as_IntConstant();
544 IntConstant* t2 = v->type()->as_IntConstant();
545 return (t1 != NULL && t2 != NULL &&
546 t1->value() == t2->value());
547 }
548 case longTag:
549 {
550 LongConstant* t1 = type()->as_LongConstant();
551 LongConstant* t2 = v->type()->as_LongConstant();
552 return (t1 != NULL && t2 != NULL &&
553 t1->value() == t2->value());
554 }
555 case floatTag:
556 {
557 FloatConstant* t1 = type()->as_FloatConstant();
558 FloatConstant* t2 = v->type()->as_FloatConstant();
559 return (t1 != NULL && t2 != NULL &&
560 jint_cast(t1->value()) == jint_cast(t2->value()));
561 }
562 case doubleTag:
563 {
564 DoubleConstant* t1 = type()->as_DoubleConstant();
565 DoubleConstant* t2 = v->type()->as_DoubleConstant();
566 return (t1 != NULL && t2 != NULL &&
567 jlong_cast(t1->value()) == jlong_cast(t2->value()));
568 }
569 case objectTag:
570 {
571 ObjectType* t1 = type()->as_ObjectType();
572 ObjectType* t2 = v->type()->as_ObjectType();
573 return (t1 != NULL && t2 != NULL &&
574 t1->is_loaded() && t2->is_loaded() &&
575 t1->constant_value() == t2->constant_value());
576 }
577 case metaDataTag:
578 {
579 MetadataType* t1 = type()->as_MetadataType();
580 MetadataType* t2 = v->type()->as_MetadataType();
581 return (t1 != NULL && t2 != NULL &&
582 t1->is_loaded() && t2->is_loaded() &&
583 t1->constant_value() == t2->constant_value());
584 }
585 default:
586 return false;
587 }
588 }
589
590 Constant::CompareResult Constant::compare(Instruction::Condition cond, Value right) const {
591 Constant* rc = right->as_Constant();
592 // other is not a constant
593 if (rc == NULL) return not_comparable;
594
595 ValueType* lt = type();
596 ValueType* rt = rc->type();
597 // different types
598 if (lt->base() != rt->base()) return not_comparable;
599 switch (lt->tag()) {
600 case intTag: {
601 int x = lt->as_IntConstant()->value();
602 int y = rt->as_IntConstant()->value();
603 switch (cond) {
604 case If::eql: return x == y ? cond_true : cond_false;
605 case If::neq: return x != y ? cond_true : cond_false;
606 case If::lss: return x < y ? cond_true : cond_false;
607 case If::leq: return x <= y ? cond_true : cond_false;
608 case If::gtr: return x > y ? cond_true : cond_false;
609 case If::geq: return x >= y ? cond_true : cond_false;
610 default : break;
611 }
612 break;
613 }
614 case longTag: {
615 jlong x = lt->as_LongConstant()->value();
616 jlong y = rt->as_LongConstant()->value();
617 switch (cond) {
618 case If::eql: return x == y ? cond_true : cond_false;
619 case If::neq: return x != y ? cond_true : cond_false;
620 case If::lss: return x < y ? cond_true : cond_false;
621 case If::leq: return x <= y ? cond_true : cond_false;
622 case If::gtr: return x > y ? cond_true : cond_false;
623 case If::geq: return x >= y ? cond_true : cond_false;
624 default : break;
625 }
626 break;
627 }
628 case objectTag: {
629 ciObject* xvalue = lt->as_ObjectType()->constant_value();
630 ciObject* yvalue = rt->as_ObjectType()->constant_value();
631 assert(xvalue != NULL && yvalue != NULL, "not constants");
632 if (xvalue->is_loaded() && yvalue->is_loaded()) {
633 switch (cond) {
634 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
635 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
636 default : break;
637 }
638 }
639 break;
640 }
641 case metaDataTag: {
642 ciMetadata* xvalue = lt->as_MetadataType()->constant_value();
643 ciMetadata* yvalue = rt->as_MetadataType()->constant_value();
644 assert(xvalue != NULL && yvalue != NULL, "not constants");
645 if (xvalue->is_loaded() && yvalue->is_loaded()) {
646 switch (cond) {
647 case If::eql: return xvalue == yvalue ? cond_true : cond_false;
648 case If::neq: return xvalue != yvalue ? cond_true : cond_false;
649 default : break;
650 }
651 }
652 break;
653 }
654 default:
655 break;
656 }
657 return not_comparable;
658 }
659
660
661 // Implementation of BlockBegin
662
663 void BlockBegin::set_end(BlockEnd* end) {
664 assert(end != NULL, "should not reset block end to NULL");
665 if (end == _end) {
666 return;
667 }
668 clear_end();
669
670 // Set the new end
671 _end = end;
672
673 _successors.clear();
674 // Now reset successors list based on BlockEnd
675 for (int i = 0; i < end->number_of_sux(); i++) {
676 BlockBegin* sux = end->sux_at(i);
677 _successors.append(sux);
678 sux->_predecessors.append(this);
679 }
680 _end->set_begin(this);
681 }
682
683
684 void BlockBegin::clear_end() {
685 // Must make the predecessors/successors match up with the
686 // BlockEnd's notion.
687 if (_end != NULL) {
688 // disconnect from the old end
689 _end->set_begin(NULL);
690
691 // disconnect this block from it's current successors
692 for (int i = 0; i < _successors.length(); i++) {
693 _successors.at(i)->remove_predecessor(this);
694 }
695 _end = NULL;
696 }
697 }
698
699
700 void BlockBegin::disconnect_edge(BlockBegin* from, BlockBegin* to) {
701 // disconnect any edges between from and to
702 #ifndef PRODUCT
703 if (PrintIR && Verbose) {
704 tty->print_cr("Disconnected edge B%d -> B%d", from->block_id(), to->block_id());
705 }
706 #endif
707 for (int s = 0; s < from->number_of_sux();) {
708 BlockBegin* sux = from->sux_at(s);
709 if (sux == to) {
710 int index = sux->_predecessors.find(from);
711 if (index >= 0) {
712 sux->_predecessors.remove_at(index);
713 }
714 from->_successors.remove_at(s);
715 } else {
716 s++;
717 }
718 }
719 }
720
721
722 void BlockBegin::disconnect_from_graph() {
723 // disconnect this block from all other blocks
724 for (int p = 0; p < number_of_preds(); p++) {
725 pred_at(p)->remove_successor(this);
726 }
727 for (int s = 0; s < number_of_sux(); s++) {
728 sux_at(s)->remove_predecessor(this);
729 }
730 }
731
732 void BlockBegin::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
733 // modify predecessors before substituting successors
734 for (int i = 0; i < number_of_sux(); i++) {
735 if (sux_at(i) == old_sux) {
736 // remove old predecessor before adding new predecessor
737 // otherwise there is a dead predecessor in the list
738 new_sux->remove_predecessor(old_sux);
739 new_sux->add_predecessor(this);
740 }
741 }
742 old_sux->remove_predecessor(this);
743 end()->substitute_sux(old_sux, new_sux);
744 }
745
746
747
748 // In general it is not possible to calculate a value for the field "depth_first_number"
749 // of the inserted block, without recomputing the values of the other blocks
750 // in the CFG. Therefore the value of "depth_first_number" in BlockBegin becomes meaningless.
751 BlockBegin* BlockBegin::insert_block_between(BlockBegin* sux) {
752 int bci = sux->bci();
753 // critical edge splitting may introduce a goto after a if and array
754 // bound check elimination may insert a predicate between the if and
755 // goto. The bci of the goto can't be the one of the if otherwise
756 // the state and bci are inconsistent and a deoptimization triggered
757 // by the predicate would lead to incorrect execution/a crash.
758 BlockBegin* new_sux = new BlockBegin(bci);
759
760 // mark this block (special treatment when block order is computed)
761 new_sux->set(critical_edge_split_flag);
762
763 // This goto is not a safepoint.
764 Goto* e = new Goto(sux, false);
765 new_sux->set_next(e, bci);
766 new_sux->set_end(e);
767 // setup states
768 ValueStack* s = end()->state();
769 new_sux->set_state(s->copy(s->kind(), bci));
770 e->set_state(s->copy(s->kind(), bci));
771 assert(new_sux->state()->locals_size() == s->locals_size(), "local size mismatch!");
772 assert(new_sux->state()->stack_size() == s->stack_size(), "stack size mismatch!");
773 assert(new_sux->state()->locks_size() == s->locks_size(), "locks size mismatch!");
774
775 // link predecessor to new block
776 end()->substitute_sux(sux, new_sux);
777
778 // The ordering needs to be the same, so remove the link that the
779 // set_end call above added and substitute the new_sux for this
780 // block.
781 sux->remove_predecessor(new_sux);
782
783 // the successor could be the target of a switch so it might have
784 // multiple copies of this predecessor, so substitute the new_sux
785 // for the first and delete the rest.
786 bool assigned = false;
787 BlockList& list = sux->_predecessors;
788 for (int i = 0; i < list.length(); i++) {
789 BlockBegin** b = list.adr_at(i);
790 if (*b == this) {
791 if (assigned) {
792 list.remove_at(i);
793 // reprocess this index
794 i--;
795 } else {
796 assigned = true;
797 *b = new_sux;
798 }
799 // link the new block back to it's predecessors.
800 new_sux->add_predecessor(this);
801 }
802 }
803 assert(assigned == true, "should have assigned at least once");
804 return new_sux;
805 }
806
807
808 void BlockBegin::remove_successor(BlockBegin* pred) {
809 int idx;
810 while ((idx = _successors.find(pred)) >= 0) {
811 _successors.remove_at(idx);
812 }
813 }
814
815
816 void BlockBegin::add_predecessor(BlockBegin* pred) {
817 _predecessors.append(pred);
818 }
819
820
821 void BlockBegin::remove_predecessor(BlockBegin* pred) {
822 int idx;
823 while ((idx = _predecessors.find(pred)) >= 0) {
824 _predecessors.remove_at(idx);
825 }
826 }
827
828
829 void BlockBegin::add_exception_handler(BlockBegin* b) {
830 assert(b != NULL && (b->is_set(exception_entry_flag)), "exception handler must exist");
831 // add only if not in the list already
832 if (!_exception_handlers.contains(b)) _exception_handlers.append(b);
833 }
834
835 int BlockBegin::add_exception_state(ValueStack* state) {
836 assert(is_set(exception_entry_flag), "only for xhandlers");
837 if (_exception_states == NULL) {
838 _exception_states = new ValueStackStack(4);
839 }
840 _exception_states->append(state);
841 return _exception_states->length() - 1;
842 }
843
844
845 void BlockBegin::iterate_preorder(boolArray& mark, BlockClosure* closure) {
846 if (!mark.at(block_id())) {
847 mark.at_put(block_id(), true);
848 closure->block_do(this);
849 BlockEnd* e = end(); // must do this after block_do because block_do may change it!
850 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_preorder(mark, closure); }
851 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_preorder(mark, closure); }
852 }
853 }
854
855
856 void BlockBegin::iterate_postorder(boolArray& mark, BlockClosure* closure) {
857 if (!mark.at(block_id())) {
858 mark.at_put(block_id(), true);
859 BlockEnd* e = end();
860 { for (int i = number_of_exception_handlers() - 1; i >= 0; i--) exception_handler_at(i)->iterate_postorder(mark, closure); }
861 { for (int i = e->number_of_sux () - 1; i >= 0; i--) e->sux_at (i)->iterate_postorder(mark, closure); }
862 closure->block_do(this);
863 }
864 }
865
866
867 void BlockBegin::iterate_preorder(BlockClosure* closure) {
868 int mark_len = number_of_blocks();
869 boolArray mark(mark_len, mark_len, false);
870 iterate_preorder(mark, closure);
871 }
872
873
874 void BlockBegin::iterate_postorder(BlockClosure* closure) {
875 int mark_len = number_of_blocks();
876 boolArray mark(mark_len, mark_len, false);
877 iterate_postorder(mark, closure);
878 }
879
880
881 void BlockBegin::block_values_do(ValueVisitor* f) {
882 for (Instruction* n = this; n != NULL; n = n->next()) n->values_do(f);
883 }
884
885
886 #ifndef PRODUCT
887 #define TRACE_PHI(code) if (PrintPhiFunctions) { code; }
888 #else
889 #define TRACE_PHI(coce)
890 #endif
891
892
893 bool BlockBegin::try_merge(ValueStack* new_state) {
894 TRACE_PHI(tty->print_cr("********** try_merge for block B%d", block_id()));
895
896 // local variables used for state iteration
897 int index;
898 Value new_value, existing_value;
899
900 ValueStack* existing_state = state();
901 if (existing_state == NULL) {
902 TRACE_PHI(tty->print_cr("first call of try_merge for this block"));
903
904 if (is_set(BlockBegin::was_visited_flag)) {
905 // this actually happens for complicated jsr/ret structures
906 return false; // BAILOUT in caller
907 }
908
909 // copy state because it is altered
910 new_state = new_state->copy(ValueStack::BlockBeginState, bci());
911
912 // Use method liveness to invalidate dead locals
913 MethodLivenessResult liveness = new_state->scope()->method()->liveness_at_bci(bci());
914 if (liveness.is_valid()) {
915 assert((int)liveness.size() == new_state->locals_size(), "error in use of liveness");
916
917 for_each_local_value(new_state, index, new_value) {
918 if (!liveness.at(index) || new_value->type()->is_illegal()) {
919 new_state->invalidate_local(index);
920 TRACE_PHI(tty->print_cr("invalidating dead local %d", index));
921 }
922 }
923 }
924
925 if (is_set(BlockBegin::parser_loop_header_flag)) {
926 TRACE_PHI(tty->print_cr("loop header block, initializing phi functions"));
927
928 for_each_stack_value(new_state, index, new_value) {
929 new_state->setup_phi_for_stack(this, index, NULL, new_value);
930 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));
931 }
932
933 BitMap& requires_phi_function = new_state->scope()->requires_phi_function();
934
935 for_each_local_value(new_state, index, new_value) {
936 bool requires_phi = requires_phi_function.at(index) || (new_value->type()->is_double_word() && requires_phi_function.at(index + 1));
937 if (requires_phi || !SelectivePhiFunctions) {
938 new_state->setup_phi_for_local(this, index, NULL, new_value);
939 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));
940 }
941 }
942 }
943
944 // initialize state of block
945 set_state(new_state);
946
947 } else if (existing_state->is_same(new_state)) {
948 TRACE_PHI(tty->print_cr("exisiting state found"));
949
950 assert(existing_state->scope() == new_state->scope(), "not matching");
951 assert(existing_state->locals_size() == new_state->locals_size(), "not matching");
952 assert(existing_state->stack_size() == new_state->stack_size(), "not matching");
953
954 if (is_set(BlockBegin::was_visited_flag)) {
955 TRACE_PHI(tty->print_cr("loop header block, phis must be present"));
956
957 if (!is_set(BlockBegin::parser_loop_header_flag)) {
958 // this actually happens for complicated jsr/ret structures
959 return false; // BAILOUT in caller
960 }
961
962 for_each_local_value(existing_state, index, existing_value) {
963 Value new_value = new_state->local_at(index);
964 if (new_value == NULL || new_value->type()->tag() != existing_value->type()->tag()) {
965 Phi* existing_phi = existing_value->as_Phi();
966 if (existing_phi == NULL) {
967 return false; // BAILOUT in caller
968 }
969 // Invalidate the phi function here. This case is very rare except for
970 // JVMTI capability "can_access_local_variables".
971 // In really rare cases we will bail out in LIRGenerator::move_to_phi.
972 existing_phi->make_illegal();
973 existing_state->invalidate_local(index);
974 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
975 }
976 }
977
978 #ifdef ASSERT
979 // check that all necessary phi functions are present
980 for_each_stack_value(existing_state, index, existing_value) {
981 assert(existing_value->as_Phi() != NULL && existing_value->as_Phi()->block() == this, "phi function required");
982 }
983 for_each_local_value(existing_state, index, existing_value) {
984 assert(existing_value == new_state->local_at(index) || (existing_value->as_Phi() != NULL && existing_value->as_Phi()->as_Phi()->block() == this), "phi function required");
985 }
986 #endif
987
988 } else {
989 TRACE_PHI(tty->print_cr("creating phi functions on demand"));
990
991 // create necessary phi functions for stack
992 for_each_stack_value(existing_state, index, existing_value) {
993 Value new_value = new_state->stack_at(index);
994 Phi* existing_phi = existing_value->as_Phi();
995
996 if (new_value != existing_value && (existing_phi == NULL || existing_phi->block() != this)) {
997 existing_state->setup_phi_for_stack(this, index, existing_value, new_value);
998 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));
999 }
1000 }
1001
1002 // create necessary phi functions for locals
1003 for_each_local_value(existing_state, index, existing_value) {
1004 Value new_value = new_state->local_at(index);
1005 Phi* existing_phi = existing_value->as_Phi();
1006
1007 if (new_value == NULL || new_value->type()->tag() != existing_value->type()->tag()) {
1008 existing_state->invalidate_local(index);
1009 TRACE_PHI(tty->print_cr("invalidating local %d because of type mismatch", index));
1010 } else if (new_value != existing_value && (existing_phi == NULL || existing_phi->block() != this)) {
1011 existing_state->setup_phi_for_local(this, index, existing_value, new_value);
1012 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));
1013 }
1014 }
1015 }
1016
1017 assert(existing_state->caller_state() == new_state->caller_state(), "caller states must be equal");
1018
1019 } else {
1020 assert(false, "stack or locks not matching (invalid bytecodes)");
1021 return false;
1022 }
1023
1024 TRACE_PHI(tty->print_cr("********** try_merge for block B%d successful", block_id()));
1025
1026 return true;
1027 }
1028
1029
1030 #ifndef PRODUCT
1031 void BlockBegin::print_block() {
1032 InstructionPrinter ip;
1033 print_block(ip, false);
1034 }
1035
1036
1037 void BlockBegin::print_block(InstructionPrinter& ip, bool live_only) {
1038 ip.print_instr(this); tty->cr();
1039 ip.print_stack(this->state()); tty->cr();
1040 ip.print_inline_level(this);
1041 ip.print_head();
1042 for (Instruction* n = next(); n != NULL; n = n->next()) {
1043 if (!live_only || n->is_pinned() || n->use_count() > 0) {
1044 ip.print_line(n);
1045 }
1046 }
1047 tty->cr();
1048 }
1049 #endif // PRODUCT
1050
1051
1052 // Implementation of BlockList
1053
1054 void BlockList::iterate_forward (BlockClosure* closure) {
1055 const int l = length();
1056 for (int i = 0; i < l; i++) closure->block_do(at(i));
1057 }
1058
1059
1060 void BlockList::iterate_backward(BlockClosure* closure) {
1061 for (int i = length() - 1; i >= 0; i--) closure->block_do(at(i));
1062 }
1063
1064
1065 void BlockList::blocks_do(void f(BlockBegin*)) {
1066 for (int i = length() - 1; i >= 0; i--) f(at(i));
1067 }
1068
1069
1070 void BlockList::values_do(ValueVisitor* f) {
1071 for (int i = length() - 1; i >= 0; i--) at(i)->block_values_do(f);
1072 }
1073
1074
1075 #ifndef PRODUCT
1076 void BlockList::print(bool cfg_only, bool live_only) {
1077 InstructionPrinter ip;
1078 for (int i = 0; i < length(); i++) {
1079 BlockBegin* block = at(i);
1080 if (cfg_only) {
1081 ip.print_instr(block); tty->cr();
1082 } else {
1083 block->print_block(ip, live_only);
1084 }
1085 }
1086 }
1087 #endif // PRODUCT
1088
1089
1090 // Implementation of BlockEnd
1091
1092 void BlockEnd::set_begin(BlockBegin* begin) {
1093 BlockList* sux = NULL;
1094 if (begin != NULL) {
1095 sux = begin->successors();
1096 } else if (this->begin() != NULL) {
1097 // copy our sux list
1098 BlockList* sux = new BlockList(this->begin()->number_of_sux());
1099 for (int i = 0; i < this->begin()->number_of_sux(); i++) {
1100 sux->append(this->begin()->sux_at(i));
1101 }
1102 }
1103 _sux = sux;
1104 }
1105
1106
1107 void BlockEnd::substitute_sux(BlockBegin* old_sux, BlockBegin* new_sux) {
1108 substitute(*_sux, old_sux, new_sux);
1109 }
1110
1111
1112 // Implementation of Phi
1113
1114 // Normal phi functions take their operands from the last instruction of the
1115 // predecessor. Special handling is needed for xhanlder entries because there
1116 // the state of arbitrary instructions are needed.
1117
1118 Value Phi::operand_at(int i) const {
1119 ValueStack* state;
1120 if (_block->is_set(BlockBegin::exception_entry_flag)) {
1121 state = _block->exception_state_at(i);
1122 } else {
1123 state = _block->pred_at(i)->end()->state();
1124 }
1125 assert(state != NULL, "");
1126
1127 if (is_local()) {
1128 return state->local_at(local_index());
1129 } else {
1130 return state->stack_at(stack_index());
1131 }
1132 }
1133
1134
1135 int Phi::operand_count() const {
1136 if (_block->is_set(BlockBegin::exception_entry_flag)) {
1137 return _block->number_of_exception_states();
1138 } else {
1139 return _block->number_of_preds();
1140 }
1141 }
1142
1143 #ifdef ASSERT
1144 // Constructor of Assert
1145 Assert::Assert(Value x, Condition cond, bool unordered_is_true, Value y) : Instruction(illegalType)
1146 , _x(x)
1147 , _cond(cond)
1148 , _y(y)
1149 {
1150 set_flag(UnorderedIsTrueFlag, unordered_is_true);
1151 assert(x->type()->tag() == y->type()->tag(), "types must match");
1152 pin();
1153
1154 stringStream strStream;
1155 Compilation::current()->method()->print_name(&strStream);
1156
1157 stringStream strStream1;
1158 InstructionPrinter ip1(1, &strStream1);
1159 ip1.print_instr(x);
1160
1161 stringStream strStream2;
1162 InstructionPrinter ip2(1, &strStream2);
1163 ip2.print_instr(y);
1164
1165 stringStream ss;
1166 ss.print("Assertion %s %s %s in method %s", strStream1.as_string(), ip2.cond_name(cond), strStream2.as_string(), strStream.as_string());
1167
1168 _message = ss.as_string();
1169 }
1170 #endif
1171
1172 void RangeCheckPredicate::check_state() {
1173 assert(state()->kind() != ValueStack::EmptyExceptionState && state()->kind() != ValueStack::ExceptionState, "will deopt with empty state");
1174 }
1175
1176 void ProfileInvoke::state_values_do(ValueVisitor* f) {
1177 if (state() != NULL) state()->values_do(f);
1178 }