1 /*
2 * Copyright (c) 2000, 2025, 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).
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23 */
24
25 #include "ci/ciConstant.hpp"
26 #include "ci/ciField.hpp"
27 #include "ci/ciInlineKlass.hpp"
28 #include "ci/ciMethod.hpp"
29 #include "ci/ciMethodData.hpp"
30 #include "ci/ciObjArrayKlass.hpp"
31 #include "ci/ciStreams.hpp"
32 #include "ci/ciTypeArrayKlass.hpp"
33 #include "ci/ciTypeFlow.hpp"
34 #include "compiler/compileLog.hpp"
35 #include "interpreter/bytecode.hpp"
36 #include "interpreter/bytecodes.hpp"
37 #include "memory/allocation.inline.hpp"
38 #include "memory/resourceArea.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "opto/compile.hpp"
41 #include "runtime/deoptimization.hpp"
42 #include "utilities/growableArray.hpp"
43
44 // ciTypeFlow::JsrSet
45 //
46 // A JsrSet represents some set of JsrRecords. This class
47 // is used to record a set of all jsr routines which we permit
48 // execution to return (ret) from.
49 //
50 // During abstract interpretation, JsrSets are used to determine
51 // whether two paths which reach a given block are unique, and
52 // should be cloned apart, or are compatible, and should merge
53 // together.
54
55 // ------------------------------------------------------------------
56 // ciTypeFlow::JsrSet::JsrSet
57
58 // Allocate growable array storage in Arena.
59 ciTypeFlow::JsrSet::JsrSet(Arena* arena, int default_len) : _set(arena, default_len, 0, nullptr) {
60 assert(arena != nullptr, "invariant");
61 }
62
63 // Allocate growable array storage in current ResourceArea.
64 ciTypeFlow::JsrSet::JsrSet(int default_len) : _set(default_len, 0, nullptr) {}
65
66 // ------------------------------------------------------------------
67 // ciTypeFlow::JsrSet::copy_into
68 void ciTypeFlow::JsrSet::copy_into(JsrSet* jsrs) {
69 int len = size();
70 jsrs->_set.clear();
71 for (int i = 0; i < len; i++) {
72 jsrs->_set.append(_set.at(i));
73 }
74 }
75
76 // ------------------------------------------------------------------
77 // ciTypeFlow::JsrSet::is_compatible_with
78 //
79 // !!!! MISGIVINGS ABOUT THIS... disregard
80 //
81 // Is this JsrSet compatible with some other JsrSet?
82 //
83 // In set-theoretic terms, a JsrSet can be viewed as a partial function
84 // from entry addresses to return addresses. Two JsrSets A and B are
85 // compatible iff
86 //
87 // For any x,
88 // A(x) defined and B(x) defined implies A(x) == B(x)
89 //
90 // Less formally, two JsrSets are compatible when they have identical
91 // return addresses for any entry addresses they share in common.
92 bool ciTypeFlow::JsrSet::is_compatible_with(JsrSet* other) {
93 // Walk through both sets in parallel. If the same entry address
94 // appears in both sets, then the return address must match for
95 // the sets to be compatible.
96 int size1 = size();
97 int size2 = other->size();
98
99 // Special case. If nothing is on the jsr stack, then there can
100 // be no ret.
101 if (size2 == 0) {
102 return true;
103 } else if (size1 != size2) {
104 return false;
105 } else {
106 for (int i = 0; i < size1; i++) {
107 JsrRecord* record1 = record_at(i);
108 JsrRecord* record2 = other->record_at(i);
109 if (record1->entry_address() != record2->entry_address() ||
110 record1->return_address() != record2->return_address()) {
111 return false;
112 }
113 }
114 return true;
115 }
116
117 #if 0
118 int pos1 = 0;
119 int pos2 = 0;
120 int size1 = size();
121 int size2 = other->size();
122 while (pos1 < size1 && pos2 < size2) {
123 JsrRecord* record1 = record_at(pos1);
124 JsrRecord* record2 = other->record_at(pos2);
125 int entry1 = record1->entry_address();
126 int entry2 = record2->entry_address();
127 if (entry1 < entry2) {
128 pos1++;
129 } else if (entry1 > entry2) {
130 pos2++;
131 } else {
132 if (record1->return_address() == record2->return_address()) {
133 pos1++;
134 pos2++;
135 } else {
136 // These two JsrSets are incompatible.
137 return false;
138 }
139 }
140 }
141 // The two JsrSets agree.
142 return true;
143 #endif
144 }
145
146 // ------------------------------------------------------------------
147 // ciTypeFlow::JsrSet::insert_jsr_record
148 //
149 // Insert the given JsrRecord into the JsrSet, maintaining the order
150 // of the set and replacing any element with the same entry address.
151 void ciTypeFlow::JsrSet::insert_jsr_record(JsrRecord* record) {
152 int len = size();
153 int entry = record->entry_address();
154 int pos = 0;
155 for ( ; pos < len; pos++) {
156 JsrRecord* current = record_at(pos);
157 if (entry == current->entry_address()) {
158 // Stomp over this entry.
159 _set.at_put(pos, record);
160 assert(size() == len, "must be same size");
161 return;
162 } else if (entry < current->entry_address()) {
163 break;
164 }
165 }
166
167 // Insert the record into the list.
168 JsrRecord* swap = record;
169 JsrRecord* temp = nullptr;
170 for ( ; pos < len; pos++) {
171 temp = _set.at(pos);
172 _set.at_put(pos, swap);
173 swap = temp;
174 }
175 _set.append(swap);
176 assert(size() == len+1, "must be larger");
177 }
178
179 // ------------------------------------------------------------------
180 // ciTypeFlow::JsrSet::remove_jsr_record
181 //
182 // Remove the JsrRecord with the given return address from the JsrSet.
183 void ciTypeFlow::JsrSet::remove_jsr_record(int return_address) {
184 int len = size();
185 for (int i = 0; i < len; i++) {
186 if (record_at(i)->return_address() == return_address) {
187 // We have found the proper entry. Remove it from the
188 // JsrSet and exit.
189 for (int j = i + 1; j < len ; j++) {
190 _set.at_put(j - 1, _set.at(j));
191 }
192 _set.trunc_to(len - 1);
193 assert(size() == len-1, "must be smaller");
194 return;
195 }
196 }
197 assert(false, "verify: returning from invalid subroutine");
198 }
199
200 // ------------------------------------------------------------------
201 // ciTypeFlow::JsrSet::apply_control
202 //
203 // Apply the effect of a control-flow bytecode on the JsrSet. The
204 // only bytecodes that modify the JsrSet are jsr and ret.
205 void ciTypeFlow::JsrSet::apply_control(ciTypeFlow* analyzer,
206 ciBytecodeStream* str,
207 ciTypeFlow::StateVector* state) {
208 Bytecodes::Code code = str->cur_bc();
209 if (code == Bytecodes::_jsr) {
210 JsrRecord* record =
211 analyzer->make_jsr_record(str->get_dest(), str->next_bci());
212 insert_jsr_record(record);
213 } else if (code == Bytecodes::_jsr_w) {
214 JsrRecord* record =
215 analyzer->make_jsr_record(str->get_far_dest(), str->next_bci());
216 insert_jsr_record(record);
217 } else if (code == Bytecodes::_ret) {
218 Cell local = state->local(str->get_index());
219 ciType* return_address = state->type_at(local);
220 assert(return_address->is_return_address(), "verify: wrong type");
221 if (size() == 0) {
222 // Ret-state underflow: Hit a ret w/o any previous jsrs. Bail out.
223 // This can happen when a loop is inside a finally clause (4614060).
224 analyzer->record_failure("OSR in finally clause");
225 return;
226 }
227 remove_jsr_record(return_address->as_return_address()->bci());
228 }
229 }
230
231 #ifndef PRODUCT
232 // ------------------------------------------------------------------
233 // ciTypeFlow::JsrSet::print_on
234 void ciTypeFlow::JsrSet::print_on(outputStream* st) const {
235 st->print("{ ");
236 int num_elements = size();
237 if (num_elements > 0) {
238 int i = 0;
239 for( ; i < num_elements - 1; i++) {
240 _set.at(i)->print_on(st);
241 st->print(", ");
242 }
243 _set.at(i)->print_on(st);
244 st->print(" ");
245 }
246 st->print("}");
247 }
248 #endif
249
250 // ciTypeFlow::StateVector
251 //
252 // A StateVector summarizes the type information at some point in
253 // the program.
254
255 // ------------------------------------------------------------------
256 // ciTypeFlow::StateVector::type_meet
257 //
258 // Meet two types.
259 //
260 // The semi-lattice of types use by this analysis are modeled on those
261 // of the verifier. The lattice is as follows:
262 //
263 // top_type() >= all non-extremal types >= bottom_type
264 // and
265 // Every primitive type is comparable only with itself. The meet of
266 // reference types is determined by their kind: instance class,
267 // interface, or array class. The meet of two types of the same
268 // kind is their least common ancestor. The meet of two types of
269 // different kinds is always java.lang.Object.
270 ciType* ciTypeFlow::StateVector::type_meet_internal(ciType* t1, ciType* t2, ciTypeFlow* analyzer) {
271 assert(t1 != t2, "checked in caller");
272 if (t1->equals(top_type())) {
273 return t2;
274 } else if (t2->equals(top_type())) {
275 return t1;
276 }
277 // Unwrap after saving nullness information and handling top meets
278 bool null_free1 = t1->is_null_free();
279 bool null_free2 = t2->is_null_free();
280 if (t1->unwrap() == t2->unwrap() && null_free1 == null_free2) {
281 return t1;
282 }
283 t1 = t1->unwrap();
284 t2 = t2->unwrap();
285
286 if (t1->is_primitive_type() || t2->is_primitive_type()) {
287 // Special case null_type. null_type meet any reference type T
288 // is T. null_type meet null_type is null_type.
289 if (t1->equals(null_type())) {
290 if (!t2->is_primitive_type() || t2->equals(null_type())) {
291 return t2;
292 }
293 } else if (t2->equals(null_type())) {
294 if (!t1->is_primitive_type()) {
295 return t1;
296 }
297 }
298
299 // At least one of the two types is a non-top primitive type.
300 // The other type is not equal to it. Fall to bottom.
301 return bottom_type();
302 }
303
304 // Both types are non-top non-primitive types. That is,
305 // both types are either instanceKlasses or arrayKlasses.
306 ciKlass* object_klass = analyzer->env()->Object_klass();
307 ciKlass* k1 = t1->as_klass();
308 ciKlass* k2 = t2->as_klass();
309 if (k1->equals(object_klass) || k2->equals(object_klass)) {
310 return object_klass;
311 } else if (!k1->is_loaded() || !k2->is_loaded()) {
312 // Unloaded classes fall to java.lang.Object at a merge.
313 return object_klass;
314 } else if (k1->is_interface() != k2->is_interface()) {
315 // When an interface meets a non-interface, we get Object;
316 // This is what the verifier does.
317 return object_klass;
318 } else if (k1->is_array_klass() || k2->is_array_klass()) {
319 // When an array meets a non-array, we get Object.
320 // When (obj/flat)Array meets typeArray, we also get Object.
321 // And when typeArray meets different typeArray, we again get Object.
322 // But when (obj/flat)Array meets (obj/flat)Array, we look carefully at element types.
323 if ((k1->is_obj_array_klass() || k1->is_flat_array_klass()) &&
324 (k2->is_obj_array_klass() || k2->is_flat_array_klass())) {
325 ciType* elem1 = k1->as_array_klass()->element_klass();
326 ciType* elem2 = k2->as_array_klass()->element_klass();
327 ciType* elem = elem1;
328 if (elem1 != elem2) {
329 elem = type_meet_internal(elem1, elem2, analyzer)->as_klass();
330 }
331 // Do an easy shortcut if one type is a super of the other.
332 if (elem == elem1 && !elem->is_inlinetype()) {
333 assert(k1 == ciArrayKlass::make(elem), "shortcut is OK");
334 return k1;
335 } else if (elem == elem2 && !elem->is_inlinetype()) {
336 assert(k2 == ciArrayKlass::make(elem), "shortcut is OK");
337 return k2;
338 } else {
339 return ciArrayKlass::make(elem);
340 }
341 } else {
342 return object_klass;
343 }
344 } else {
345 // Must be two plain old instance klasses.
346 assert(k1->is_instance_klass(), "previous cases handle non-instances");
347 assert(k2->is_instance_klass(), "previous cases handle non-instances");
348 ciType* result = k1->least_common_ancestor(k2);
349 if (null_free1 && null_free2 && result->is_inlinetype()) {
350 result = analyzer->mark_as_null_free(result);
351 }
352 return result;
353 }
354 }
355
356
357 // ------------------------------------------------------------------
358 // ciTypeFlow::StateVector::StateVector
359 //
360 // Build a new state vector
361 ciTypeFlow::StateVector::StateVector(ciTypeFlow* analyzer) {
362 _outer = analyzer;
363 _stack_size = -1;
364 _monitor_count = -1;
365 // Allocate the _types array
366 int max_cells = analyzer->max_cells();
367 _types = (ciType**)analyzer->arena()->Amalloc(sizeof(ciType*) * max_cells);
368 for (int i=0; i<max_cells; i++) {
369 _types[i] = top_type();
370 }
371 _trap_bci = -1;
372 _trap_index = 0;
373 _def_locals.clear();
374 }
375
376
377 // ------------------------------------------------------------------
378 // ciTypeFlow::get_start_state
379 //
380 // Set this vector to the method entry state.
381 const ciTypeFlow::StateVector* ciTypeFlow::get_start_state() {
382 StateVector* state = new StateVector(this);
383 if (is_osr_flow()) {
384 ciTypeFlow* non_osr_flow = method()->get_flow_analysis();
385 if (non_osr_flow->failing()) {
386 record_failure(non_osr_flow->failure_reason());
387 return nullptr;
388 }
389 JsrSet* jsrs = new JsrSet(4);
390 Block* non_osr_block = non_osr_flow->existing_block_at(start_bci(), jsrs);
391 if (non_osr_block == nullptr) {
392 record_failure("cannot reach OSR point");
393 return nullptr;
394 }
395 // load up the non-OSR state at this point
396 non_osr_block->copy_state_into(state);
397 int non_osr_start = non_osr_block->start();
398 if (non_osr_start != start_bci()) {
399 // must flow forward from it
400 if (CITraceTypeFlow) {
401 tty->print_cr(">> Interpreting pre-OSR block %d:", non_osr_start);
402 }
403 Block* block = block_at(non_osr_start, jsrs);
404 assert(block->limit() == start_bci(), "must flow forward to start");
405 flow_block(block, state, jsrs);
406 }
407 return state;
408 // Note: The code below would be an incorrect for an OSR flow,
409 // even if it were possible for an OSR entry point to be at bci zero.
410 }
411 // "Push" the method signature into the first few locals.
412 state->set_stack_size(-max_locals());
413 if (!method()->is_static()) {
414 ciType* holder = method()->holder();
415 if (holder->is_inlinetype()) {
416 // The receiver is null-free
417 holder = mark_as_null_free(holder);
418 }
419 state->push(holder);
420 assert(state->tos() == state->local(0), "");
421 }
422 for (ciSignatureStream str(method()->signature());
423 !str.at_return_type();
424 str.next()) {
425 state->push_translate(str.type());
426 }
427 // Set the rest of the locals to bottom.
428 assert(state->stack_size() <= 0, "stack size should not be strictly positive");
429 while (state->stack_size() < 0) {
430 state->push(state->bottom_type());
431 }
432 // Lock an object, if necessary.
433 state->set_monitor_count(method()->is_synchronized() ? 1 : 0);
434 return state;
435 }
436
437 // ------------------------------------------------------------------
438 // ciTypeFlow::StateVector::copy_into
439 //
440 // Copy our value into some other StateVector
441 void ciTypeFlow::StateVector::copy_into(ciTypeFlow::StateVector* copy)
442 const {
443 copy->set_stack_size(stack_size());
444 copy->set_monitor_count(monitor_count());
445 Cell limit = limit_cell();
446 for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
447 copy->set_type_at(c, type_at(c));
448 }
449 }
450
451 // ------------------------------------------------------------------
452 // ciTypeFlow::StateVector::meet
453 //
454 // Meets this StateVector with another, destructively modifying this
455 // one. Returns true if any modification takes place.
456 bool ciTypeFlow::StateVector::meet(const ciTypeFlow::StateVector* incoming) {
457 if (monitor_count() == -1) {
458 set_monitor_count(incoming->monitor_count());
459 }
460 assert(monitor_count() == incoming->monitor_count(), "monitors must match");
461
462 if (stack_size() == -1) {
463 set_stack_size(incoming->stack_size());
464 Cell limit = limit_cell();
465 #ifdef ASSERT
466 { for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
467 assert(type_at(c) == top_type(), "");
468 } }
469 #endif
470 // Make a simple copy of the incoming state.
471 for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
472 set_type_at(c, incoming->type_at(c));
473 }
474 return true; // it is always different the first time
475 }
476 #ifdef ASSERT
477 if (stack_size() != incoming->stack_size()) {
478 _outer->method()->print_codes();
479 tty->print_cr("!!!! Stack size conflict");
480 tty->print_cr("Current state:");
481 print_on(tty);
482 tty->print_cr("Incoming state:");
483 ((StateVector*)incoming)->print_on(tty);
484 }
485 #endif
486 assert(stack_size() == incoming->stack_size(), "sanity");
487
488 bool different = false;
489 Cell limit = limit_cell();
490 for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
491 ciType* t1 = type_at(c);
492 ciType* t2 = incoming->type_at(c);
493 if (!t1->equals(t2)) {
494 ciType* new_type = type_meet(t1, t2);
495 if (!t1->equals(new_type)) {
496 set_type_at(c, new_type);
497 different = true;
498 }
499 }
500 }
501 return different;
502 }
503
504 // ------------------------------------------------------------------
505 // ciTypeFlow::StateVector::meet_exception
506 //
507 // Meets this StateVector with another, destructively modifying this
508 // one. The incoming state is coming via an exception. Returns true
509 // if any modification takes place.
510 bool ciTypeFlow::StateVector::meet_exception(ciInstanceKlass* exc,
511 const ciTypeFlow::StateVector* incoming) {
512 if (monitor_count() == -1) {
513 set_monitor_count(incoming->monitor_count());
514 }
515 assert(monitor_count() == incoming->monitor_count(), "monitors must match");
516
517 if (stack_size() == -1) {
518 set_stack_size(1);
519 }
520
521 assert(stack_size() == 1, "must have one-element stack");
522
523 bool different = false;
524
525 // Meet locals from incoming array.
526 Cell limit = local_limit_cell();
527 for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
528 ciType* t1 = type_at(c);
529 ciType* t2 = incoming->type_at(c);
530 if (!t1->equals(t2)) {
531 ciType* new_type = type_meet(t1, t2);
532 if (!t1->equals(new_type)) {
533 set_type_at(c, new_type);
534 different = true;
535 }
536 }
537 }
538
539 // Handle stack separately. When an exception occurs, the
540 // only stack entry is the exception instance.
541 ciType* tos_type = type_at_tos();
542 if (!tos_type->equals(exc)) {
543 ciType* new_type = type_meet(tos_type, exc);
544 if (!tos_type->equals(new_type)) {
545 set_type_at_tos(new_type);
546 different = true;
547 }
548 }
549
550 return different;
551 }
552
553 // ------------------------------------------------------------------
554 // ciTypeFlow::StateVector::push_translate
555 void ciTypeFlow::StateVector::push_translate(ciType* type) {
556 BasicType basic_type = type->basic_type();
557 if (basic_type == T_BOOLEAN || basic_type == T_CHAR ||
558 basic_type == T_BYTE || basic_type == T_SHORT) {
559 push_int();
560 } else {
561 push(type);
562 if (type->is_two_word()) {
563 push(half_type(type));
564 }
565 }
566 }
567
568 // ------------------------------------------------------------------
569 // ciTypeFlow::StateVector::do_aload
570 void ciTypeFlow::StateVector::do_aload(ciBytecodeStream* str) {
571 pop_int();
572 ciArrayKlass* array_klass = pop_objOrFlatArray();
573 if (array_klass == nullptr) {
574 // Did aload on a null reference; push a null and ignore the exception.
575 // This instruction will never continue normally. All we have to do
576 // is report a value that will meet correctly with any downstream
577 // reference types on paths that will truly be executed. This null type
578 // meets with any reference type to yield that same reference type.
579 // (The compiler will generate an unconditional exception here.)
580 push(null_type());
581 return;
582 }
583 if (!array_klass->is_loaded()) {
584 // Only fails for some -Xcomp runs
585 trap(str, array_klass,
586 Deoptimization::make_trap_request
587 (Deoptimization::Reason_unloaded,
588 Deoptimization::Action_reinterpret));
589 return;
590 }
591 ciKlass* element_klass = array_klass->element_klass();
592 if (!element_klass->is_loaded() && element_klass->is_instance_klass()) {
593 Untested("unloaded array element class in ciTypeFlow");
594 trap(str, element_klass,
595 Deoptimization::make_trap_request
596 (Deoptimization::Reason_unloaded,
597 Deoptimization::Action_reinterpret));
598 } else {
599 push_object(element_klass);
600 }
601 }
602
603
604 // ------------------------------------------------------------------
605 // ciTypeFlow::StateVector::do_checkcast
606 void ciTypeFlow::StateVector::do_checkcast(ciBytecodeStream* str) {
607 bool will_link;
608 ciKlass* klass = str->get_klass(will_link);
609 if (!will_link) {
610 // VM's interpreter will not load 'klass' if object is nullptr.
611 // Type flow after this block may still be needed in two situations:
612 // 1) C2 uses do_null_assert() and continues compilation for later blocks
613 // 2) C2 does an OSR compile in a later block (see bug 4778368).
614 pop_object();
615 do_null_assert(klass);
616 } else {
617 ciType* type = pop_value();
618 type = type->unwrap();
619 if (type->is_loaded() && klass->is_loaded() &&
620 type != klass && type->is_subtype_of(klass)) {
621 // Useless cast, propagate more precise type of object
622 klass = type->as_klass();
623 }
624 push_object(klass);
625 }
626 }
627
628 // ------------------------------------------------------------------
629 // ciTypeFlow::StateVector::do_getfield
630 void ciTypeFlow::StateVector::do_getfield(ciBytecodeStream* str) {
631 // could add assert here for type of object.
632 pop_object();
633 do_getstatic(str);
634 }
635
636 // ------------------------------------------------------------------
637 // ciTypeFlow::StateVector::do_getstatic
638 void ciTypeFlow::StateVector::do_getstatic(ciBytecodeStream* str) {
639 bool will_link;
640 ciField* field = str->get_field(will_link);
641 if (!will_link) {
642 trap(str, field->holder(), str->get_field_holder_index());
643 } else {
644 ciType* field_type = field->type();
645 if (field->is_static() && field->is_null_free() &&
646 !field_type->as_instance_klass()->is_initialized()) {
647 // Deoptimize if we load from a static field with an uninitialized inline type
648 // because we need to throw an exception if initialization of the type failed.
649 trap(str, field_type->as_klass(),
650 Deoptimization::make_trap_request
651 (Deoptimization::Reason_unloaded,
652 Deoptimization::Action_reinterpret));
653 return;
654 } else if (!field_type->is_loaded()) {
655 // Normally, we need the field's type to be loaded if we are to
656 // do anything interesting with its value.
657 // We used to do this: trap(str, str->get_field_signature_index());
658 //
659 // There is one good reason not to trap here. Execution can
660 // get past this "getfield" or "getstatic" if the value of
661 // the field is null. As long as the value is null, the class
662 // does not need to be loaded! The compiler must assume that
663 // the value of the unloaded class reference is null; if the code
664 // ever sees a non-null value, loading has occurred.
665 //
666 // This actually happens often enough to be annoying. If the
667 // compiler throws an uncommon trap at this bytecode, you can
668 // get an endless loop of recompilations, when all the code
669 // needs to do is load a series of null values. Also, a trap
670 // here can make an OSR entry point unreachable, triggering the
671 // assert on non_osr_block in ciTypeFlow::get_start_state.
672 // (See bug 4379915.)
673 do_null_assert(field_type->as_klass());
674 } else {
675 if (field->is_null_free()) {
676 field_type = outer()->mark_as_null_free(field_type);
677 }
678 push_translate(field_type);
679 }
680 }
681 }
682
683 // ------------------------------------------------------------------
684 // ciTypeFlow::StateVector::do_invoke
685 void ciTypeFlow::StateVector::do_invoke(ciBytecodeStream* str,
686 bool has_receiver) {
687 bool will_link;
688 ciSignature* declared_signature = nullptr;
689 ciMethod* callee = str->get_method(will_link, &declared_signature);
690 assert(declared_signature != nullptr, "cannot be null");
691 if (!will_link) {
692 // We weren't able to find the method.
693 if (str->cur_bc() == Bytecodes::_invokedynamic) {
694 trap(str, nullptr,
695 Deoptimization::make_trap_request
696 (Deoptimization::Reason_uninitialized,
697 Deoptimization::Action_reinterpret));
698 } else {
699 ciKlass* unloaded_holder = callee->holder();
700 trap(str, unloaded_holder, str->get_method_holder_index());
701 }
702 } else {
703 // We are using the declared signature here because it might be
704 // different from the callee signature (Cf. invokedynamic and
705 // invokehandle).
706 ciSignatureStream sigstr(declared_signature);
707 const int arg_size = declared_signature->size();
708 const int stack_base = stack_size() - arg_size;
709 int i = 0;
710 for( ; !sigstr.at_return_type(); sigstr.next()) {
711 ciType* type = sigstr.type();
712 ciType* stack_type = type_at(stack(stack_base + i++));
713 // Do I want to check this type?
714 // assert(stack_type->is_subtype_of(type), "bad type for field value");
715 if (type->is_two_word()) {
716 ciType* stack_type2 = type_at(stack(stack_base + i++));
717 assert(stack_type2->equals(half_type(type)), "must be 2nd half");
718 }
719 }
720 assert(arg_size == i, "must match");
721 for (int j = 0; j < arg_size; j++) {
722 pop();
723 }
724 if (has_receiver) {
725 // Check this?
726 pop_object();
727 }
728 assert(!sigstr.is_done(), "must have return type");
729 ciType* return_type = sigstr.type();
730 if (!return_type->is_void()) {
731 if (!return_type->is_loaded()) {
732 // As in do_getstatic(), generally speaking, we need the return type to
733 // be loaded if we are to do anything interesting with its value.
734 // We used to do this: trap(str, str->get_method_signature_index());
735 //
736 // We do not trap here since execution can get past this invoke if
737 // the return value is null. As long as the value is null, the class
738 // does not need to be loaded! The compiler must assume that
739 // the value of the unloaded class reference is null; if the code
740 // ever sees a non-null value, loading has occurred.
741 //
742 // See do_getstatic() for similar explanation, as well as bug 4684993.
743 if (InlineTypeReturnedAsFields) {
744 // Return might be in scalarized form but we can't handle it because we
745 // don't know the type. This can happen due to a missing preload attribute.
746 // TODO 8284443 Use PhaseMacroExpand::expand_mh_intrinsic_return for this
747 trap(str, nullptr,
748 Deoptimization::make_trap_request
749 (Deoptimization::Reason_uninitialized,
750 Deoptimization::Action_reinterpret));
751 } else {
752 do_null_assert(return_type->as_klass());
753 }
754 } else {
755 push_translate(return_type);
756 }
757 }
758 }
759 }
760
761 // ------------------------------------------------------------------
762 // ciTypeFlow::StateVector::do_jsr
763 void ciTypeFlow::StateVector::do_jsr(ciBytecodeStream* str) {
764 push(ciReturnAddress::make(str->next_bci()));
765 }
766
767 // ------------------------------------------------------------------
768 // ciTypeFlow::StateVector::do_ldc
769 void ciTypeFlow::StateVector::do_ldc(ciBytecodeStream* str) {
770 if (str->is_in_error()) {
771 trap(str, nullptr, Deoptimization::make_trap_request(Deoptimization::Reason_unhandled,
772 Deoptimization::Action_none));
773 return;
774 }
775 ciConstant con = str->get_constant();
776 if (con.is_valid()) {
777 int cp_index = str->get_constant_pool_index();
778 if (!con.is_loaded()) {
779 trap(str, nullptr, Deoptimization::make_trap_request(Deoptimization::Reason_unloaded,
780 Deoptimization::Action_reinterpret,
781 cp_index));
782 return;
783 }
784 BasicType basic_type = str->get_basic_type_for_constant_at(cp_index);
785 if (is_reference_type(basic_type)) {
786 ciObject* obj = con.as_object();
787 if (obj->is_null_object()) {
788 push_null();
789 } else {
790 assert(obj->is_instance() || obj->is_array(), "must be java_mirror of klass");
791 ciType* type = obj->klass();
792 if (type->is_inlinetype()) {
793 type = outer()->mark_as_null_free(type);
794 }
795 push(type);
796 }
797 } else {
798 assert(basic_type == con.basic_type() || con.basic_type() == T_OBJECT,
799 "not a boxed form: %s vs %s", type2name(basic_type), type2name(con.basic_type()));
800 push_translate(ciType::make(basic_type));
801 }
802 } else {
803 // OutOfMemoryError in the CI while loading a String constant.
804 push_null();
805 outer()->record_failure("ldc did not link");
806 }
807 }
808
809 // ------------------------------------------------------------------
810 // ciTypeFlow::StateVector::do_multianewarray
811 void ciTypeFlow::StateVector::do_multianewarray(ciBytecodeStream* str) {
812 int dimensions = str->get_dimensions();
813 bool will_link;
814 ciArrayKlass* array_klass = str->get_klass(will_link)->as_array_klass();
815 if (!will_link) {
816 trap(str, array_klass, str->get_klass_index());
817 } else {
818 for (int i = 0; i < dimensions; i++) {
819 pop_int();
820 }
821 push_object(array_klass);
822 }
823 }
824
825 // ------------------------------------------------------------------
826 // ciTypeFlow::StateVector::do_new
827 void ciTypeFlow::StateVector::do_new(ciBytecodeStream* str) {
828 bool will_link;
829 ciKlass* klass = str->get_klass(will_link);
830 if (!will_link || str->is_unresolved_klass()) {
831 trap(str, klass, str->get_klass_index());
832 } else {
833 push_object(klass);
834 }
835 }
836
837 // ------------------------------------------------------------------
838 // ciTypeFlow::StateVector::do_newarray
839 void ciTypeFlow::StateVector::do_newarray(ciBytecodeStream* str) {
840 pop_int();
841 ciKlass* klass = ciTypeArrayKlass::make((BasicType)str->get_index());
842 push_object(klass);
843 }
844
845 // ------------------------------------------------------------------
846 // ciTypeFlow::StateVector::do_putfield
847 void ciTypeFlow::StateVector::do_putfield(ciBytecodeStream* str) {
848 do_putstatic(str);
849 if (_trap_bci != -1) return; // unloaded field holder, etc.
850 // could add assert here for type of object.
851 pop_object();
852 }
853
854 // ------------------------------------------------------------------
855 // ciTypeFlow::StateVector::do_putstatic
856 void ciTypeFlow::StateVector::do_putstatic(ciBytecodeStream* str) {
857 bool will_link;
858 ciField* field = str->get_field(will_link);
859 if (!will_link) {
860 trap(str, field->holder(), str->get_field_holder_index());
861 } else {
862 ciType* field_type = field->type();
863 ciType* type = pop_value();
864 // Do I want to check this type?
865 // assert(type->is_subtype_of(field_type), "bad type for field value");
866 if (field_type->is_two_word()) {
867 ciType* type2 = pop_value();
868 assert(type2->is_two_word(), "must be 2nd half");
869 assert(type == half_type(type2), "must be 2nd half");
870 }
871 }
872 }
873
874 // ------------------------------------------------------------------
875 // ciTypeFlow::StateVector::do_ret
876 void ciTypeFlow::StateVector::do_ret(ciBytecodeStream* str) {
877 Cell index = local(str->get_index());
878
879 ciType* address = type_at(index);
880 assert(address->is_return_address(), "bad return address");
881 set_type_at(index, bottom_type());
882 }
883
884 // ------------------------------------------------------------------
885 // ciTypeFlow::StateVector::trap
886 //
887 // Stop interpretation of this path with a trap.
888 void ciTypeFlow::StateVector::trap(ciBytecodeStream* str, ciKlass* klass, int index) {
889 _trap_bci = str->cur_bci();
890 _trap_index = index;
891
892 // Log information about this trap:
893 CompileLog* log = outer()->env()->log();
894 if (log != nullptr) {
895 int mid = log->identify(outer()->method());
896 int kid = (klass == nullptr)? -1: log->identify(klass);
897 log->begin_elem("uncommon_trap method='%d' bci='%d'", mid, str->cur_bci());
898 char buf[100];
899 log->print(" %s", Deoptimization::format_trap_request(buf, sizeof(buf),
900 index));
901 if (kid >= 0)
902 log->print(" klass='%d'", kid);
903 log->end_elem();
904 }
905 }
906
907 // ------------------------------------------------------------------
908 // ciTypeFlow::StateVector::do_null_assert
909 // Corresponds to graphKit::do_null_assert.
910 void ciTypeFlow::StateVector::do_null_assert(ciKlass* unloaded_klass) {
911 if (unloaded_klass->is_loaded()) {
912 // We failed to link, but we can still compute with this class,
913 // since it is loaded somewhere. The compiler will uncommon_trap
914 // if the object is not null, but the typeflow pass can not assume
915 // that the object will be null, otherwise it may incorrectly tell
916 // the parser that an object is known to be null. 4761344, 4807707
917 push_object(unloaded_klass);
918 } else {
919 // The class is not loaded anywhere. It is safe to model the
920 // null in the typestates, because we can compile in a null check
921 // which will deoptimize us if someone manages to load the
922 // class later.
923 push_null();
924 }
925 }
926
927
928 // ------------------------------------------------------------------
929 // ciTypeFlow::StateVector::apply_one_bytecode
930 //
931 // Apply the effect of one bytecode to this StateVector
932 bool ciTypeFlow::StateVector::apply_one_bytecode(ciBytecodeStream* str) {
933 _trap_bci = -1;
934 _trap_index = 0;
935
936 if (CITraceTypeFlow) {
937 tty->print_cr(">> Interpreting bytecode %d:%s", str->cur_bci(),
938 Bytecodes::name(str->cur_bc()));
939 }
940
941 switch(str->cur_bc()) {
942 case Bytecodes::_aaload: do_aload(str); break;
943
944 case Bytecodes::_aastore:
945 {
946 pop_object();
947 pop_int();
948 pop_objOrFlatArray();
949 break;
950 }
951 case Bytecodes::_aconst_null:
952 {
953 push_null();
954 break;
955 }
956 case Bytecodes::_aload: load_local_object(str->get_index()); break;
957 case Bytecodes::_aload_0: load_local_object(0); break;
958 case Bytecodes::_aload_1: load_local_object(1); break;
959 case Bytecodes::_aload_2: load_local_object(2); break;
960 case Bytecodes::_aload_3: load_local_object(3); break;
961
962 case Bytecodes::_anewarray:
963 {
964 pop_int();
965 bool will_link;
966 ciKlass* element_klass = str->get_klass(will_link);
967 if (!will_link) {
968 trap(str, element_klass, str->get_klass_index());
969 } else {
970 push_object(ciArrayKlass::make(element_klass));
971 }
972 break;
973 }
974 case Bytecodes::_areturn:
975 case Bytecodes::_ifnonnull:
976 case Bytecodes::_ifnull:
977 {
978 pop_object();
979 break;
980 }
981 case Bytecodes::_monitorenter:
982 {
983 pop_object();
984 set_monitor_count(monitor_count() + 1);
985 break;
986 }
987 case Bytecodes::_monitorexit:
988 {
989 pop_object();
990 assert(monitor_count() > 0, "must be a monitor to exit from");
991 set_monitor_count(monitor_count() - 1);
992 break;
993 }
994 case Bytecodes::_arraylength:
995 {
996 pop_array();
997 push_int();
998 break;
999 }
1000 case Bytecodes::_astore: store_local_object(str->get_index()); break;
1001 case Bytecodes::_astore_0: store_local_object(0); break;
1002 case Bytecodes::_astore_1: store_local_object(1); break;
1003 case Bytecodes::_astore_2: store_local_object(2); break;
1004 case Bytecodes::_astore_3: store_local_object(3); break;
1005
1006 case Bytecodes::_athrow:
1007 {
1008 NEEDS_CLEANUP;
1009 pop_object();
1010 break;
1011 }
1012 case Bytecodes::_baload:
1013 case Bytecodes::_caload:
1014 case Bytecodes::_iaload:
1015 case Bytecodes::_saload:
1016 {
1017 pop_int();
1018 ciTypeArrayKlass* array_klass = pop_typeArray();
1019 // Put assert here for right type?
1020 push_int();
1021 break;
1022 }
1023 case Bytecodes::_bastore:
1024 case Bytecodes::_castore:
1025 case Bytecodes::_iastore:
1026 case Bytecodes::_sastore:
1027 {
1028 pop_int();
1029 pop_int();
1030 pop_typeArray();
1031 // assert here?
1032 break;
1033 }
1034 case Bytecodes::_bipush:
1035 case Bytecodes::_iconst_m1:
1036 case Bytecodes::_iconst_0:
1037 case Bytecodes::_iconst_1:
1038 case Bytecodes::_iconst_2:
1039 case Bytecodes::_iconst_3:
1040 case Bytecodes::_iconst_4:
1041 case Bytecodes::_iconst_5:
1042 case Bytecodes::_sipush:
1043 {
1044 push_int();
1045 break;
1046 }
1047 case Bytecodes::_checkcast: do_checkcast(str); break;
1048
1049 case Bytecodes::_d2f:
1050 {
1051 pop_double();
1052 push_float();
1053 break;
1054 }
1055 case Bytecodes::_d2i:
1056 {
1057 pop_double();
1058 push_int();
1059 break;
1060 }
1061 case Bytecodes::_d2l:
1062 {
1063 pop_double();
1064 push_long();
1065 break;
1066 }
1067 case Bytecodes::_dadd:
1068 case Bytecodes::_ddiv:
1069 case Bytecodes::_dmul:
1070 case Bytecodes::_drem:
1071 case Bytecodes::_dsub:
1072 {
1073 pop_double();
1074 pop_double();
1075 push_double();
1076 break;
1077 }
1078 case Bytecodes::_daload:
1079 {
1080 pop_int();
1081 ciTypeArrayKlass* array_klass = pop_typeArray();
1082 // Put assert here for right type?
1083 push_double();
1084 break;
1085 }
1086 case Bytecodes::_dastore:
1087 {
1088 pop_double();
1089 pop_int();
1090 pop_typeArray();
1091 // assert here?
1092 break;
1093 }
1094 case Bytecodes::_dcmpg:
1095 case Bytecodes::_dcmpl:
1096 {
1097 pop_double();
1098 pop_double();
1099 push_int();
1100 break;
1101 }
1102 case Bytecodes::_dconst_0:
1103 case Bytecodes::_dconst_1:
1104 {
1105 push_double();
1106 break;
1107 }
1108 case Bytecodes::_dload: load_local_double(str->get_index()); break;
1109 case Bytecodes::_dload_0: load_local_double(0); break;
1110 case Bytecodes::_dload_1: load_local_double(1); break;
1111 case Bytecodes::_dload_2: load_local_double(2); break;
1112 case Bytecodes::_dload_3: load_local_double(3); break;
1113
1114 case Bytecodes::_dneg:
1115 {
1116 pop_double();
1117 push_double();
1118 break;
1119 }
1120 case Bytecodes::_dreturn:
1121 {
1122 pop_double();
1123 break;
1124 }
1125 case Bytecodes::_dstore: store_local_double(str->get_index()); break;
1126 case Bytecodes::_dstore_0: store_local_double(0); break;
1127 case Bytecodes::_dstore_1: store_local_double(1); break;
1128 case Bytecodes::_dstore_2: store_local_double(2); break;
1129 case Bytecodes::_dstore_3: store_local_double(3); break;
1130
1131 case Bytecodes::_dup:
1132 {
1133 push(type_at_tos());
1134 break;
1135 }
1136 case Bytecodes::_dup_x1:
1137 {
1138 ciType* value1 = pop_value();
1139 ciType* value2 = pop_value();
1140 push(value1);
1141 push(value2);
1142 push(value1);
1143 break;
1144 }
1145 case Bytecodes::_dup_x2:
1146 {
1147 ciType* value1 = pop_value();
1148 ciType* value2 = pop_value();
1149 ciType* value3 = pop_value();
1150 push(value1);
1151 push(value3);
1152 push(value2);
1153 push(value1);
1154 break;
1155 }
1156 case Bytecodes::_dup2:
1157 {
1158 ciType* value1 = pop_value();
1159 ciType* value2 = pop_value();
1160 push(value2);
1161 push(value1);
1162 push(value2);
1163 push(value1);
1164 break;
1165 }
1166 case Bytecodes::_dup2_x1:
1167 {
1168 ciType* value1 = pop_value();
1169 ciType* value2 = pop_value();
1170 ciType* value3 = pop_value();
1171 push(value2);
1172 push(value1);
1173 push(value3);
1174 push(value2);
1175 push(value1);
1176 break;
1177 }
1178 case Bytecodes::_dup2_x2:
1179 {
1180 ciType* value1 = pop_value();
1181 ciType* value2 = pop_value();
1182 ciType* value3 = pop_value();
1183 ciType* value4 = pop_value();
1184 push(value2);
1185 push(value1);
1186 push(value4);
1187 push(value3);
1188 push(value2);
1189 push(value1);
1190 break;
1191 }
1192 case Bytecodes::_f2d:
1193 {
1194 pop_float();
1195 push_double();
1196 break;
1197 }
1198 case Bytecodes::_f2i:
1199 {
1200 pop_float();
1201 push_int();
1202 break;
1203 }
1204 case Bytecodes::_f2l:
1205 {
1206 pop_float();
1207 push_long();
1208 break;
1209 }
1210 case Bytecodes::_fadd:
1211 case Bytecodes::_fdiv:
1212 case Bytecodes::_fmul:
1213 case Bytecodes::_frem:
1214 case Bytecodes::_fsub:
1215 {
1216 pop_float();
1217 pop_float();
1218 push_float();
1219 break;
1220 }
1221 case Bytecodes::_faload:
1222 {
1223 pop_int();
1224 ciTypeArrayKlass* array_klass = pop_typeArray();
1225 // Put assert here.
1226 push_float();
1227 break;
1228 }
1229 case Bytecodes::_fastore:
1230 {
1231 pop_float();
1232 pop_int();
1233 ciTypeArrayKlass* array_klass = pop_typeArray();
1234 // Put assert here.
1235 break;
1236 }
1237 case Bytecodes::_fcmpg:
1238 case Bytecodes::_fcmpl:
1239 {
1240 pop_float();
1241 pop_float();
1242 push_int();
1243 break;
1244 }
1245 case Bytecodes::_fconst_0:
1246 case Bytecodes::_fconst_1:
1247 case Bytecodes::_fconst_2:
1248 {
1249 push_float();
1250 break;
1251 }
1252 case Bytecodes::_fload: load_local_float(str->get_index()); break;
1253 case Bytecodes::_fload_0: load_local_float(0); break;
1254 case Bytecodes::_fload_1: load_local_float(1); break;
1255 case Bytecodes::_fload_2: load_local_float(2); break;
1256 case Bytecodes::_fload_3: load_local_float(3); break;
1257
1258 case Bytecodes::_fneg:
1259 {
1260 pop_float();
1261 push_float();
1262 break;
1263 }
1264 case Bytecodes::_freturn:
1265 {
1266 pop_float();
1267 break;
1268 }
1269 case Bytecodes::_fstore: store_local_float(str->get_index()); break;
1270 case Bytecodes::_fstore_0: store_local_float(0); break;
1271 case Bytecodes::_fstore_1: store_local_float(1); break;
1272 case Bytecodes::_fstore_2: store_local_float(2); break;
1273 case Bytecodes::_fstore_3: store_local_float(3); break;
1274
1275 case Bytecodes::_getfield: do_getfield(str); break;
1276 case Bytecodes::_getstatic: do_getstatic(str); break;
1277
1278 case Bytecodes::_goto:
1279 case Bytecodes::_goto_w:
1280 case Bytecodes::_nop:
1281 case Bytecodes::_return:
1282 {
1283 // do nothing.
1284 break;
1285 }
1286 case Bytecodes::_i2b:
1287 case Bytecodes::_i2c:
1288 case Bytecodes::_i2s:
1289 case Bytecodes::_ineg:
1290 {
1291 pop_int();
1292 push_int();
1293 break;
1294 }
1295 case Bytecodes::_i2d:
1296 {
1297 pop_int();
1298 push_double();
1299 break;
1300 }
1301 case Bytecodes::_i2f:
1302 {
1303 pop_int();
1304 push_float();
1305 break;
1306 }
1307 case Bytecodes::_i2l:
1308 {
1309 pop_int();
1310 push_long();
1311 break;
1312 }
1313 case Bytecodes::_iadd:
1314 case Bytecodes::_iand:
1315 case Bytecodes::_idiv:
1316 case Bytecodes::_imul:
1317 case Bytecodes::_ior:
1318 case Bytecodes::_irem:
1319 case Bytecodes::_ishl:
1320 case Bytecodes::_ishr:
1321 case Bytecodes::_isub:
1322 case Bytecodes::_iushr:
1323 case Bytecodes::_ixor:
1324 {
1325 pop_int();
1326 pop_int();
1327 push_int();
1328 break;
1329 }
1330 case Bytecodes::_if_acmpeq:
1331 case Bytecodes::_if_acmpne:
1332 {
1333 pop_object();
1334 pop_object();
1335 break;
1336 }
1337 case Bytecodes::_if_icmpeq:
1338 case Bytecodes::_if_icmpge:
1339 case Bytecodes::_if_icmpgt:
1340 case Bytecodes::_if_icmple:
1341 case Bytecodes::_if_icmplt:
1342 case Bytecodes::_if_icmpne:
1343 {
1344 pop_int();
1345 pop_int();
1346 break;
1347 }
1348 case Bytecodes::_ifeq:
1349 case Bytecodes::_ifle:
1350 case Bytecodes::_iflt:
1351 case Bytecodes::_ifge:
1352 case Bytecodes::_ifgt:
1353 case Bytecodes::_ifne:
1354 case Bytecodes::_ireturn:
1355 case Bytecodes::_lookupswitch:
1356 case Bytecodes::_tableswitch:
1357 {
1358 pop_int();
1359 break;
1360 }
1361 case Bytecodes::_iinc:
1362 {
1363 int lnum = str->get_index();
1364 check_int(local(lnum));
1365 store_to_local(lnum);
1366 break;
1367 }
1368 case Bytecodes::_iload: load_local_int(str->get_index()); break;
1369 case Bytecodes::_iload_0: load_local_int(0); break;
1370 case Bytecodes::_iload_1: load_local_int(1); break;
1371 case Bytecodes::_iload_2: load_local_int(2); break;
1372 case Bytecodes::_iload_3: load_local_int(3); break;
1373
1374 case Bytecodes::_instanceof:
1375 {
1376 // Check for uncommon trap:
1377 do_checkcast(str);
1378 pop_object();
1379 push_int();
1380 break;
1381 }
1382 case Bytecodes::_invokeinterface: do_invoke(str, true); break;
1383 case Bytecodes::_invokespecial: do_invoke(str, true); break;
1384 case Bytecodes::_invokestatic: do_invoke(str, false); break;
1385 case Bytecodes::_invokevirtual: do_invoke(str, true); break;
1386 case Bytecodes::_invokedynamic: do_invoke(str, false); break;
1387
1388 case Bytecodes::_istore: store_local_int(str->get_index()); break;
1389 case Bytecodes::_istore_0: store_local_int(0); break;
1390 case Bytecodes::_istore_1: store_local_int(1); break;
1391 case Bytecodes::_istore_2: store_local_int(2); break;
1392 case Bytecodes::_istore_3: store_local_int(3); break;
1393
1394 case Bytecodes::_jsr:
1395 case Bytecodes::_jsr_w: do_jsr(str); break;
1396
1397 case Bytecodes::_l2d:
1398 {
1399 pop_long();
1400 push_double();
1401 break;
1402 }
1403 case Bytecodes::_l2f:
1404 {
1405 pop_long();
1406 push_float();
1407 break;
1408 }
1409 case Bytecodes::_l2i:
1410 {
1411 pop_long();
1412 push_int();
1413 break;
1414 }
1415 case Bytecodes::_ladd:
1416 case Bytecodes::_land:
1417 case Bytecodes::_ldiv:
1418 case Bytecodes::_lmul:
1419 case Bytecodes::_lor:
1420 case Bytecodes::_lrem:
1421 case Bytecodes::_lsub:
1422 case Bytecodes::_lxor:
1423 {
1424 pop_long();
1425 pop_long();
1426 push_long();
1427 break;
1428 }
1429 case Bytecodes::_laload:
1430 {
1431 pop_int();
1432 ciTypeArrayKlass* array_klass = pop_typeArray();
1433 // Put assert here for right type?
1434 push_long();
1435 break;
1436 }
1437 case Bytecodes::_lastore:
1438 {
1439 pop_long();
1440 pop_int();
1441 pop_typeArray();
1442 // assert here?
1443 break;
1444 }
1445 case Bytecodes::_lcmp:
1446 {
1447 pop_long();
1448 pop_long();
1449 push_int();
1450 break;
1451 }
1452 case Bytecodes::_lconst_0:
1453 case Bytecodes::_lconst_1:
1454 {
1455 push_long();
1456 break;
1457 }
1458 case Bytecodes::_ldc:
1459 case Bytecodes::_ldc_w:
1460 case Bytecodes::_ldc2_w:
1461 {
1462 do_ldc(str);
1463 break;
1464 }
1465
1466 case Bytecodes::_lload: load_local_long(str->get_index()); break;
1467 case Bytecodes::_lload_0: load_local_long(0); break;
1468 case Bytecodes::_lload_1: load_local_long(1); break;
1469 case Bytecodes::_lload_2: load_local_long(2); break;
1470 case Bytecodes::_lload_3: load_local_long(3); break;
1471
1472 case Bytecodes::_lneg:
1473 {
1474 pop_long();
1475 push_long();
1476 break;
1477 }
1478 case Bytecodes::_lreturn:
1479 {
1480 pop_long();
1481 break;
1482 }
1483 case Bytecodes::_lshl:
1484 case Bytecodes::_lshr:
1485 case Bytecodes::_lushr:
1486 {
1487 pop_int();
1488 pop_long();
1489 push_long();
1490 break;
1491 }
1492 case Bytecodes::_lstore: store_local_long(str->get_index()); break;
1493 case Bytecodes::_lstore_0: store_local_long(0); break;
1494 case Bytecodes::_lstore_1: store_local_long(1); break;
1495 case Bytecodes::_lstore_2: store_local_long(2); break;
1496 case Bytecodes::_lstore_3: store_local_long(3); break;
1497
1498 case Bytecodes::_multianewarray: do_multianewarray(str); break;
1499
1500 case Bytecodes::_new: do_new(str); break;
1501
1502 case Bytecodes::_newarray: do_newarray(str); break;
1503
1504 case Bytecodes::_pop:
1505 {
1506 pop();
1507 break;
1508 }
1509 case Bytecodes::_pop2:
1510 {
1511 pop();
1512 pop();
1513 break;
1514 }
1515
1516 case Bytecodes::_putfield: do_putfield(str); break;
1517 case Bytecodes::_putstatic: do_putstatic(str); break;
1518
1519 case Bytecodes::_ret: do_ret(str); break;
1520
1521 case Bytecodes::_swap:
1522 {
1523 ciType* value1 = pop_value();
1524 ciType* value2 = pop_value();
1525 push(value1);
1526 push(value2);
1527 break;
1528 }
1529
1530 case Bytecodes::_wide:
1531 default:
1532 {
1533 // The iterator should skip this.
1534 ShouldNotReachHere();
1535 break;
1536 }
1537 }
1538
1539 if (CITraceTypeFlow) {
1540 print_on(tty);
1541 }
1542
1543 return (_trap_bci != -1);
1544 }
1545
1546 #ifndef PRODUCT
1547 // ------------------------------------------------------------------
1548 // ciTypeFlow::StateVector::print_cell_on
1549 void ciTypeFlow::StateVector::print_cell_on(outputStream* st, Cell c) const {
1550 ciType* type = type_at(c)->unwrap();
1551 if (type == top_type()) {
1552 st->print("top");
1553 } else if (type == bottom_type()) {
1554 st->print("bottom");
1555 } else if (type == null_type()) {
1556 st->print("null");
1557 } else if (type == long2_type()) {
1558 st->print("long2");
1559 } else if (type == double2_type()) {
1560 st->print("double2");
1561 } else if (is_int(type)) {
1562 st->print("int");
1563 } else if (is_long(type)) {
1564 st->print("long");
1565 } else if (is_float(type)) {
1566 st->print("float");
1567 } else if (is_double(type)) {
1568 st->print("double");
1569 } else if (type->is_return_address()) {
1570 st->print("address(%d)", type->as_return_address()->bci());
1571 } else {
1572 if (type->is_klass()) {
1573 type->as_klass()->name()->print_symbol_on(st);
1574 } else {
1575 st->print("UNEXPECTED TYPE");
1576 type->print();
1577 }
1578 }
1579 }
1580
1581 // ------------------------------------------------------------------
1582 // ciTypeFlow::StateVector::print_on
1583 void ciTypeFlow::StateVector::print_on(outputStream* st) const {
1584 int num_locals = _outer->max_locals();
1585 int num_stack = stack_size();
1586 int num_monitors = monitor_count();
1587 st->print_cr(" State : locals %d, stack %d, monitors %d", num_locals, num_stack, num_monitors);
1588 if (num_stack >= 0) {
1589 int i;
1590 for (i = 0; i < num_locals; i++) {
1591 st->print(" local %2d : ", i);
1592 print_cell_on(st, local(i));
1593 st->cr();
1594 }
1595 for (i = 0; i < num_stack; i++) {
1596 st->print(" stack %2d : ", i);
1597 print_cell_on(st, stack(i));
1598 st->cr();
1599 }
1600 }
1601 }
1602 #endif
1603
1604
1605 // ------------------------------------------------------------------
1606 // ciTypeFlow::SuccIter::next
1607 //
1608 void ciTypeFlow::SuccIter::next() {
1609 int succ_ct = _pred->successors()->length();
1610 int next = _index + 1;
1611 if (next < succ_ct) {
1612 _index = next;
1613 _succ = _pred->successors()->at(next);
1614 return;
1615 }
1616 for (int i = next - succ_ct; i < _pred->exceptions()->length(); i++) {
1617 // Do not compile any code for unloaded exception types.
1618 // Following compiler passes are responsible for doing this also.
1619 ciInstanceKlass* exception_klass = _pred->exc_klasses()->at(i);
1620 if (exception_klass->is_loaded()) {
1621 _index = next;
1622 _succ = _pred->exceptions()->at(i);
1623 return;
1624 }
1625 next++;
1626 }
1627 _index = -1;
1628 _succ = nullptr;
1629 }
1630
1631 // ------------------------------------------------------------------
1632 // ciTypeFlow::SuccIter::set_succ
1633 //
1634 void ciTypeFlow::SuccIter::set_succ(Block* succ) {
1635 int succ_ct = _pred->successors()->length();
1636 if (_index < succ_ct) {
1637 _pred->successors()->at_put(_index, succ);
1638 } else {
1639 int idx = _index - succ_ct;
1640 _pred->exceptions()->at_put(idx, succ);
1641 }
1642 }
1643
1644 // ciTypeFlow::Block
1645 //
1646 // A basic block.
1647
1648 // ------------------------------------------------------------------
1649 // ciTypeFlow::Block::Block
1650 ciTypeFlow::Block::Block(ciTypeFlow* outer,
1651 ciBlock *ciblk,
1652 ciTypeFlow::JsrSet* jsrs) : _predecessors(outer->arena(), 1, 0, nullptr) {
1653 _ciblock = ciblk;
1654 _exceptions = nullptr;
1655 _exc_klasses = nullptr;
1656 _successors = nullptr;
1657 _state = new (outer->arena()) StateVector(outer);
1658 JsrSet* new_jsrs =
1659 new (outer->arena()) JsrSet(outer->arena(), jsrs->size());
1660 jsrs->copy_into(new_jsrs);
1661 _jsrs = new_jsrs;
1662 _next = nullptr;
1663 _on_work_list = false;
1664 _backedge_copy = false;
1665 _has_monitorenter = false;
1666 _trap_bci = -1;
1667 _trap_index = 0;
1668 df_init();
1669
1670 if (CITraceTypeFlow) {
1671 tty->print_cr(">> Created new block");
1672 print_on(tty);
1673 }
1674
1675 assert(this->outer() == outer, "outer link set up");
1676 assert(!outer->have_block_count(), "must not have mapped blocks yet");
1677 }
1678
1679 // ------------------------------------------------------------------
1680 // ciTypeFlow::Block::df_init
1681 void ciTypeFlow::Block::df_init() {
1682 _pre_order = -1; assert(!has_pre_order(), "");
1683 _post_order = -1; assert(!has_post_order(), "");
1684 _loop = nullptr;
1685 _irreducible_loop_head = false;
1686 _irreducible_loop_secondary_entry = false;
1687 _rpo_next = nullptr;
1688 }
1689
1690 // ------------------------------------------------------------------
1691 // ciTypeFlow::Block::successors
1692 //
1693 // Get the successors for this Block.
1694 GrowableArray<ciTypeFlow::Block*>*
1695 ciTypeFlow::Block::successors(ciBytecodeStream* str,
1696 ciTypeFlow::StateVector* state,
1697 ciTypeFlow::JsrSet* jsrs) {
1698 if (_successors == nullptr) {
1699 if (CITraceTypeFlow) {
1700 tty->print(">> Computing successors for block ");
1701 print_value_on(tty);
1702 tty->cr();
1703 }
1704
1705 ciTypeFlow* analyzer = outer();
1706 Arena* arena = analyzer->arena();
1707 Block* block = nullptr;
1708 bool has_successor = !has_trap() &&
1709 (control() != ciBlock::fall_through_bci || limit() < analyzer->code_size());
1710 if (!has_successor) {
1711 _successors =
1712 new (arena) GrowableArray<Block*>(arena, 1, 0, nullptr);
1713 // No successors
1714 } else if (control() == ciBlock::fall_through_bci) {
1715 assert(str->cur_bci() == limit(), "bad block end");
1716 // This block simply falls through to the next.
1717 _successors =
1718 new (arena) GrowableArray<Block*>(arena, 1, 0, nullptr);
1719
1720 Block* block = analyzer->block_at(limit(), _jsrs);
1721 assert(_successors->length() == FALL_THROUGH, "");
1722 _successors->append(block);
1723 } else {
1724 int current_bci = str->cur_bci();
1725 int next_bci = str->next_bci();
1726 int branch_bci = -1;
1727 Block* target = nullptr;
1728 assert(str->next_bci() == limit(), "bad block end");
1729 // This block is not a simple fall-though. Interpret
1730 // the current bytecode to find our successors.
1731 switch (str->cur_bc()) {
1732 case Bytecodes::_ifeq: case Bytecodes::_ifne:
1733 case Bytecodes::_iflt: case Bytecodes::_ifge:
1734 case Bytecodes::_ifgt: case Bytecodes::_ifle:
1735 case Bytecodes::_if_icmpeq: case Bytecodes::_if_icmpne:
1736 case Bytecodes::_if_icmplt: case Bytecodes::_if_icmpge:
1737 case Bytecodes::_if_icmpgt: case Bytecodes::_if_icmple:
1738 case Bytecodes::_if_acmpeq: case Bytecodes::_if_acmpne:
1739 case Bytecodes::_ifnull: case Bytecodes::_ifnonnull:
1740 // Our successors are the branch target and the next bci.
1741 branch_bci = str->get_dest();
1742 _successors =
1743 new (arena) GrowableArray<Block*>(arena, 2, 0, nullptr);
1744 assert(_successors->length() == IF_NOT_TAKEN, "");
1745 _successors->append(analyzer->block_at(next_bci, jsrs));
1746 assert(_successors->length() == IF_TAKEN, "");
1747 _successors->append(analyzer->block_at(branch_bci, jsrs));
1748 break;
1749
1750 case Bytecodes::_goto:
1751 branch_bci = str->get_dest();
1752 _successors =
1753 new (arena) GrowableArray<Block*>(arena, 1, 0, nullptr);
1754 assert(_successors->length() == GOTO_TARGET, "");
1755 _successors->append(analyzer->block_at(branch_bci, jsrs));
1756 break;
1757
1758 case Bytecodes::_jsr:
1759 branch_bci = str->get_dest();
1760 _successors =
1761 new (arena) GrowableArray<Block*>(arena, 1, 0, nullptr);
1762 assert(_successors->length() == GOTO_TARGET, "");
1763 _successors->append(analyzer->block_at(branch_bci, jsrs));
1764 break;
1765
1766 case Bytecodes::_goto_w:
1767 case Bytecodes::_jsr_w:
1768 _successors =
1769 new (arena) GrowableArray<Block*>(arena, 1, 0, nullptr);
1770 assert(_successors->length() == GOTO_TARGET, "");
1771 _successors->append(analyzer->block_at(str->get_far_dest(), jsrs));
1772 break;
1773
1774 case Bytecodes::_tableswitch: {
1775 Bytecode_tableswitch tableswitch(str);
1776
1777 int len = tableswitch.length();
1778 _successors =
1779 new (arena) GrowableArray<Block*>(arena, len+1, 0, nullptr);
1780 int bci = current_bci + tableswitch.default_offset();
1781 Block* block = analyzer->block_at(bci, jsrs);
1782 assert(_successors->length() == SWITCH_DEFAULT, "");
1783 _successors->append(block);
1784 while (--len >= 0) {
1785 int bci = current_bci + tableswitch.dest_offset_at(len);
1786 block = analyzer->block_at(bci, jsrs);
1787 assert(_successors->length() >= SWITCH_CASES, "");
1788 _successors->append_if_missing(block);
1789 }
1790 break;
1791 }
1792
1793 case Bytecodes::_lookupswitch: {
1794 Bytecode_lookupswitch lookupswitch(str);
1795
1796 int npairs = lookupswitch.number_of_pairs();
1797 _successors =
1798 new (arena) GrowableArray<Block*>(arena, npairs+1, 0, nullptr);
1799 int bci = current_bci + lookupswitch.default_offset();
1800 Block* block = analyzer->block_at(bci, jsrs);
1801 assert(_successors->length() == SWITCH_DEFAULT, "");
1802 _successors->append(block);
1803 while(--npairs >= 0) {
1804 LookupswitchPair pair = lookupswitch.pair_at(npairs);
1805 int bci = current_bci + pair.offset();
1806 Block* block = analyzer->block_at(bci, jsrs);
1807 assert(_successors->length() >= SWITCH_CASES, "");
1808 _successors->append_if_missing(block);
1809 }
1810 break;
1811 }
1812
1813 case Bytecodes::_athrow:
1814 case Bytecodes::_ireturn:
1815 case Bytecodes::_lreturn:
1816 case Bytecodes::_freturn:
1817 case Bytecodes::_dreturn:
1818 case Bytecodes::_areturn:
1819 case Bytecodes::_return:
1820 _successors =
1821 new (arena) GrowableArray<Block*>(arena, 1, 0, nullptr);
1822 // No successors
1823 break;
1824
1825 case Bytecodes::_ret: {
1826 _successors =
1827 new (arena) GrowableArray<Block*>(arena, 1, 0, nullptr);
1828
1829 Cell local = state->local(str->get_index());
1830 ciType* return_address = state->type_at(local);
1831 assert(return_address->is_return_address(), "verify: wrong type");
1832 int bci = return_address->as_return_address()->bci();
1833 assert(_successors->length() == GOTO_TARGET, "");
1834 _successors->append(analyzer->block_at(bci, jsrs));
1835 break;
1836 }
1837
1838 case Bytecodes::_wide:
1839 default:
1840 ShouldNotReachHere();
1841 break;
1842 }
1843 }
1844
1845 // Set predecessor information
1846 for (int i = 0; i < _successors->length(); i++) {
1847 Block* block = _successors->at(i);
1848 block->predecessors()->append(this);
1849 }
1850 }
1851 return _successors;
1852 }
1853
1854 // ------------------------------------------------------------------
1855 // ciTypeFlow::Block:compute_exceptions
1856 //
1857 // Compute the exceptional successors and types for this Block.
1858 void ciTypeFlow::Block::compute_exceptions() {
1859 assert(_exceptions == nullptr && _exc_klasses == nullptr, "repeat");
1860
1861 if (CITraceTypeFlow) {
1862 tty->print(">> Computing exceptions for block ");
1863 print_value_on(tty);
1864 tty->cr();
1865 }
1866
1867 ciTypeFlow* analyzer = outer();
1868 Arena* arena = analyzer->arena();
1869
1870 // Any bci in the block will do.
1871 ciExceptionHandlerStream str(analyzer->method(), start());
1872
1873 // Allocate our growable arrays.
1874 int exc_count = str.count();
1875 _exceptions = new (arena) GrowableArray<Block*>(arena, exc_count, 0, nullptr);
1876 _exc_klasses = new (arena) GrowableArray<ciInstanceKlass*>(arena, exc_count,
1877 0, nullptr);
1878
1879 for ( ; !str.is_done(); str.next()) {
1880 ciExceptionHandler* handler = str.handler();
1881 int bci = handler->handler_bci();
1882 ciInstanceKlass* klass = nullptr;
1883 if (bci == -1) {
1884 // There is no catch all. It is possible to exit the method.
1885 break;
1886 }
1887 if (handler->is_catch_all()) {
1888 klass = analyzer->env()->Throwable_klass();
1889 } else {
1890 klass = handler->catch_klass();
1891 }
1892 Block* block = analyzer->block_at(bci, _jsrs);
1893 _exceptions->append(block);
1894 block->predecessors()->append(this);
1895 _exc_klasses->append(klass);
1896 }
1897 }
1898
1899 // ------------------------------------------------------------------
1900 // ciTypeFlow::Block::set_backedge_copy
1901 // Use this only to make a pre-existing public block into a backedge copy.
1902 void ciTypeFlow::Block::set_backedge_copy(bool z) {
1903 assert(z || (z == is_backedge_copy()), "cannot make a backedge copy public");
1904 _backedge_copy = z;
1905 }
1906
1907 // Analogous to PhaseIdealLoop::is_in_irreducible_loop
1908 bool ciTypeFlow::Block::is_in_irreducible_loop() const {
1909 if (!outer()->has_irreducible_entry()) {
1910 return false; // No irreducible loop in method.
1911 }
1912 Loop* lp = loop(); // Innermost loop containing block.
1913 if (lp == nullptr) {
1914 assert(!is_post_visited(), "must have enclosing loop once post-visited");
1915 return false; // Not yet processed, so we do not know, yet.
1916 }
1917 // Walk all the way up the loop-tree, search for an irreducible loop.
1918 do {
1919 if (lp->is_irreducible()) {
1920 return true; // We are in irreducible loop.
1921 }
1922 if (lp->head()->pre_order() == 0) {
1923 return false; // Found root loop, terminate.
1924 }
1925 lp = lp->parent();
1926 } while (lp != nullptr);
1927 // We have "lp->parent() == nullptr", which happens only for infinite loops,
1928 // where no parent is attached to the loop. We did not find any irreducible
1929 // loop from this block out to lp. Thus lp only has one entry, and no exit
1930 // (it is infinite and reducible). We can always rewrite an infinite loop
1931 // that is nested inside other loops:
1932 // while(condition) { infinite_loop; }
1933 // with an equivalent program where the infinite loop is an outermost loop
1934 // that is not nested in any loop:
1935 // while(condition) { break; } infinite_loop;
1936 // Thus, we can understand lp as an outermost loop, and can terminate and
1937 // conclude: this block is in no irreducible loop.
1938 return false;
1939 }
1940
1941 // ------------------------------------------------------------------
1942 // ciTypeFlow::Block::is_clonable_exit
1943 //
1944 // At most 2 normal successors, one of which continues looping,
1945 // and all exceptional successors must exit.
1946 bool ciTypeFlow::Block::is_clonable_exit(ciTypeFlow::Loop* lp) {
1947 int normal_cnt = 0;
1948 int in_loop_cnt = 0;
1949 for (SuccIter iter(this); !iter.done(); iter.next()) {
1950 Block* succ = iter.succ();
1951 if (iter.is_normal_ctrl()) {
1952 if (++normal_cnt > 2) return false;
1953 if (lp->contains(succ->loop())) {
1954 if (++in_loop_cnt > 1) return false;
1955 }
1956 } else {
1957 if (lp->contains(succ->loop())) return false;
1958 }
1959 }
1960 return in_loop_cnt == 1;
1961 }
1962
1963 // ------------------------------------------------------------------
1964 // ciTypeFlow::Block::looping_succ
1965 //
1966 ciTypeFlow::Block* ciTypeFlow::Block::looping_succ(ciTypeFlow::Loop* lp) {
1967 assert(successors()->length() <= 2, "at most 2 normal successors");
1968 for (SuccIter iter(this); !iter.done(); iter.next()) {
1969 Block* succ = iter.succ();
1970 if (lp->contains(succ->loop())) {
1971 return succ;
1972 }
1973 }
1974 return nullptr;
1975 }
1976
1977 #ifndef PRODUCT
1978 // ------------------------------------------------------------------
1979 // ciTypeFlow::Block::print_value_on
1980 void ciTypeFlow::Block::print_value_on(outputStream* st) const {
1981 if (has_pre_order()) st->print("#%-2d ", pre_order());
1982 if (has_rpo()) st->print("rpo#%-2d ", rpo());
1983 st->print("[%d - %d)", start(), limit());
1984 if (is_loop_head()) st->print(" lphd");
1985 if (is_in_irreducible_loop()) st->print(" in_irred");
1986 if (is_irreducible_loop_head()) st->print(" irred_head");
1987 if (is_irreducible_loop_secondary_entry()) st->print(" irred_entry");
1988 if (_jsrs->size() > 0) { st->print("/"); _jsrs->print_on(st); }
1989 if (is_backedge_copy()) st->print("/backedge_copy");
1990 }
1991
1992 // ------------------------------------------------------------------
1993 // ciTypeFlow::Block::print_on
1994 void ciTypeFlow::Block::print_on(outputStream* st) const {
1995 if ((Verbose || WizardMode) && (limit() >= 0)) {
1996 // Don't print 'dummy' blocks (i.e. blocks with limit() '-1')
1997 outer()->method()->print_codes_on(start(), limit(), st);
1998 }
1999 st->print_cr(" ==================================================== ");
2000 st->print (" ");
2001 print_value_on(st);
2002 st->print(" Stored locals: "); def_locals()->print_on(st, outer()->method()->max_locals()); tty->cr();
2003 if (loop() && loop()->parent() != nullptr) {
2004 st->print(" loops:");
2005 Loop* lp = loop();
2006 do {
2007 st->print(" %d<-%d", lp->head()->pre_order(),lp->tail()->pre_order());
2008 if (lp->is_irreducible()) st->print("(ir)");
2009 lp = lp->parent();
2010 } while (lp->parent() != nullptr);
2011 }
2012 st->cr();
2013 _state->print_on(st);
2014 if (_successors == nullptr) {
2015 st->print_cr(" No successor information");
2016 } else {
2017 int num_successors = _successors->length();
2018 st->print_cr(" Successors : %d", num_successors);
2019 for (int i = 0; i < num_successors; i++) {
2020 Block* successor = _successors->at(i);
2021 st->print(" ");
2022 successor->print_value_on(st);
2023 st->cr();
2024 }
2025 }
2026 if (_predecessors.is_empty()) {
2027 st->print_cr(" No predecessor information");
2028 } else {
2029 int num_predecessors = _predecessors.length();
2030 st->print_cr(" Predecessors : %d", num_predecessors);
2031 for (int i = 0; i < num_predecessors; i++) {
2032 Block* predecessor = _predecessors.at(i);
2033 st->print(" ");
2034 predecessor->print_value_on(st);
2035 st->cr();
2036 }
2037 }
2038 if (_exceptions == nullptr) {
2039 st->print_cr(" No exception information");
2040 } else {
2041 int num_exceptions = _exceptions->length();
2042 st->print_cr(" Exceptions : %d", num_exceptions);
2043 for (int i = 0; i < num_exceptions; i++) {
2044 Block* exc_succ = _exceptions->at(i);
2045 ciInstanceKlass* exc_klass = _exc_klasses->at(i);
2046 st->print(" ");
2047 exc_succ->print_value_on(st);
2048 st->print(" -- ");
2049 exc_klass->name()->print_symbol_on(st);
2050 st->cr();
2051 }
2052 }
2053 if (has_trap()) {
2054 st->print_cr(" Traps on %d with trap index %d", trap_bci(), trap_index());
2055 }
2056 st->print_cr(" ==================================================== ");
2057 }
2058 #endif
2059
2060 #ifndef PRODUCT
2061 // ------------------------------------------------------------------
2062 // ciTypeFlow::LocalSet::print_on
2063 void ciTypeFlow::LocalSet::print_on(outputStream* st, int limit) const {
2064 st->print("{");
2065 for (int i = 0; i < max; i++) {
2066 if (test(i)) st->print(" %d", i);
2067 }
2068 if (limit > max) {
2069 st->print(" %d..%d ", max, limit);
2070 }
2071 st->print(" }");
2072 }
2073 #endif
2074
2075 // ciTypeFlow
2076 //
2077 // This is a pass over the bytecodes which computes the following:
2078 // basic block structure
2079 // interpreter type-states (a la the verifier)
2080
2081 // ------------------------------------------------------------------
2082 // ciTypeFlow::ciTypeFlow
2083 ciTypeFlow::ciTypeFlow(ciEnv* env, ciMethod* method, int osr_bci) {
2084 _env = env;
2085 _method = method;
2086 _has_irreducible_entry = false;
2087 _osr_bci = osr_bci;
2088 _failure_reason = nullptr;
2089 assert(0 <= start_bci() && start_bci() < code_size() , "correct osr_bci argument: 0 <= %d < %d", start_bci(), code_size());
2090 _work_list = nullptr;
2091
2092 int ciblock_count = _method->get_method_blocks()->num_blocks();
2093 _idx_to_blocklist = NEW_ARENA_ARRAY(arena(), GrowableArray<Block*>*, ciblock_count);
2094 for (int i = 0; i < ciblock_count; i++) {
2095 _idx_to_blocklist[i] = nullptr;
2096 }
2097 _block_map = nullptr; // until all blocks are seen
2098 _jsr_records = nullptr;
2099 }
2100
2101 // ------------------------------------------------------------------
2102 // ciTypeFlow::work_list_next
2103 //
2104 // Get the next basic block from our work list.
2105 ciTypeFlow::Block* ciTypeFlow::work_list_next() {
2106 assert(!work_list_empty(), "work list must not be empty");
2107 Block* next_block = _work_list;
2108 _work_list = next_block->next();
2109 next_block->set_next(nullptr);
2110 next_block->set_on_work_list(false);
2111 return next_block;
2112 }
2113
2114 // ------------------------------------------------------------------
2115 // ciTypeFlow::add_to_work_list
2116 //
2117 // Add a basic block to our work list.
2118 // List is sorted by decreasing postorder sort (same as increasing RPO)
2119 void ciTypeFlow::add_to_work_list(ciTypeFlow::Block* block) {
2120 assert(!block->is_on_work_list(), "must not already be on work list");
2121
2122 if (CITraceTypeFlow) {
2123 tty->print(">> Adding block ");
2124 block->print_value_on(tty);
2125 tty->print_cr(" to the work list : ");
2126 }
2127
2128 block->set_on_work_list(true);
2129
2130 // decreasing post order sort
2131
2132 Block* prev = nullptr;
2133 Block* current = _work_list;
2134 int po = block->post_order();
2135 while (current != nullptr) {
2136 if (!current->has_post_order() || po > current->post_order())
2137 break;
2138 prev = current;
2139 current = current->next();
2140 }
2141 if (prev == nullptr) {
2142 block->set_next(_work_list);
2143 _work_list = block;
2144 } else {
2145 block->set_next(current);
2146 prev->set_next(block);
2147 }
2148
2149 if (CITraceTypeFlow) {
2150 tty->cr();
2151 }
2152 }
2153
2154 // ------------------------------------------------------------------
2155 // ciTypeFlow::block_at
2156 //
2157 // Return the block beginning at bci which has a JsrSet compatible
2158 // with jsrs.
2159 ciTypeFlow::Block* ciTypeFlow::block_at(int bci, ciTypeFlow::JsrSet* jsrs, CreateOption option) {
2160 // First find the right ciBlock.
2161 if (CITraceTypeFlow) {
2162 tty->print(">> Requesting block for %d/", bci);
2163 jsrs->print_on(tty);
2164 tty->cr();
2165 }
2166
2167 ciBlock* ciblk = _method->get_method_blocks()->block_containing(bci);
2168 assert(ciblk->start_bci() == bci, "bad ciBlock boundaries");
2169 Block* block = get_block_for(ciblk->index(), jsrs, option);
2170
2171 assert(block == nullptr? (option == no_create): block->is_backedge_copy() == (option == create_backedge_copy), "create option consistent with result");
2172
2173 if (CITraceTypeFlow) {
2174 if (block != nullptr) {
2175 tty->print(">> Found block ");
2176 block->print_value_on(tty);
2177 tty->cr();
2178 } else {
2179 tty->print_cr(">> No such block.");
2180 }
2181 }
2182
2183 return block;
2184 }
2185
2186 // ------------------------------------------------------------------
2187 // ciTypeFlow::make_jsr_record
2188 //
2189 // Make a JsrRecord for a given (entry, return) pair, if such a record
2190 // does not already exist.
2191 ciTypeFlow::JsrRecord* ciTypeFlow::make_jsr_record(int entry_address,
2192 int return_address) {
2193 if (_jsr_records == nullptr) {
2194 _jsr_records = new (arena()) GrowableArray<JsrRecord*>(arena(),
2195 2,
2196 0,
2197 nullptr);
2198 }
2199 JsrRecord* record = nullptr;
2200 int len = _jsr_records->length();
2201 for (int i = 0; i < len; i++) {
2202 JsrRecord* record = _jsr_records->at(i);
2203 if (record->entry_address() == entry_address &&
2204 record->return_address() == return_address) {
2205 return record;
2206 }
2207 }
2208
2209 record = new (arena()) JsrRecord(entry_address, return_address);
2210 _jsr_records->append(record);
2211 return record;
2212 }
2213
2214 // ------------------------------------------------------------------
2215 // ciTypeFlow::flow_exceptions
2216 //
2217 // Merge the current state into all exceptional successors at the
2218 // current point in the code.
2219 void ciTypeFlow::flow_exceptions(GrowableArray<ciTypeFlow::Block*>* exceptions,
2220 GrowableArray<ciInstanceKlass*>* exc_klasses,
2221 ciTypeFlow::StateVector* state) {
2222 int len = exceptions->length();
2223 assert(exc_klasses->length() == len, "must have same length");
2224 for (int i = 0; i < len; i++) {
2225 Block* block = exceptions->at(i);
2226 ciInstanceKlass* exception_klass = exc_klasses->at(i);
2227
2228 if (!exception_klass->is_loaded()) {
2229 // Do not compile any code for unloaded exception types.
2230 // Following compiler passes are responsible for doing this also.
2231 continue;
2232 }
2233
2234 if (block->meet_exception(exception_klass, state)) {
2235 // Block was modified and has PO. Add it to the work list.
2236 if (block->has_post_order() &&
2237 !block->is_on_work_list()) {
2238 add_to_work_list(block);
2239 }
2240 }
2241 }
2242 }
2243
2244 // ------------------------------------------------------------------
2245 // ciTypeFlow::flow_successors
2246 //
2247 // Merge the current state into all successors at the current point
2248 // in the code.
2249 void ciTypeFlow::flow_successors(GrowableArray<ciTypeFlow::Block*>* successors,
2250 ciTypeFlow::StateVector* state) {
2251 int len = successors->length();
2252 for (int i = 0; i < len; i++) {
2253 Block* block = successors->at(i);
2254 if (block->meet(state)) {
2255 // Block was modified and has PO. Add it to the work list.
2256 if (block->has_post_order() &&
2257 !block->is_on_work_list()) {
2258 add_to_work_list(block);
2259 }
2260 }
2261 }
2262 }
2263
2264 // ------------------------------------------------------------------
2265 // ciTypeFlow::can_trap
2266 //
2267 // Tells if a given instruction is able to generate an exception edge.
2268 bool ciTypeFlow::can_trap(ciBytecodeStream& str) {
2269 // Cf. GenerateOopMap::do_exception_edge.
2270 if (!Bytecodes::can_trap(str.cur_bc())) return false;
2271
2272 switch (str.cur_bc()) {
2273 case Bytecodes::_ldc:
2274 case Bytecodes::_ldc_w:
2275 case Bytecodes::_ldc2_w:
2276 return str.is_in_error() || !str.get_constant().is_loaded();
2277
2278 case Bytecodes::_aload_0:
2279 // These bytecodes can trap for rewriting. We need to assume that
2280 // they do not throw exceptions to make the monitor analysis work.
2281 return false;
2282
2283 case Bytecodes::_ireturn:
2284 case Bytecodes::_lreturn:
2285 case Bytecodes::_freturn:
2286 case Bytecodes::_dreturn:
2287 case Bytecodes::_areturn:
2288 case Bytecodes::_return:
2289 // We can assume the monitor stack is empty in this analysis.
2290 return false;
2291
2292 case Bytecodes::_monitorexit:
2293 // We can assume monitors are matched in this analysis.
2294 return false;
2295
2296 default:
2297 return true;
2298 }
2299 }
2300
2301 // ------------------------------------------------------------------
2302 // ciTypeFlow::clone_loop_heads
2303 //
2304 // Clone the loop heads
2305 bool ciTypeFlow::clone_loop_heads(StateVector* temp_vector, JsrSet* temp_set) {
2306 bool rslt = false;
2307 for (PreorderLoops iter(loop_tree_root()); !iter.done(); iter.next()) {
2308 Loop* lp = iter.current();
2309 Block* head = lp->head();
2310 if (lp == loop_tree_root() ||
2311 lp->is_irreducible() ||
2312 !head->is_clonable_exit(lp))
2313 continue;
2314
2315 // Avoid BoxLock merge.
2316 if (EliminateNestedLocks && head->has_monitorenter())
2317 continue;
2318
2319 // check not already cloned
2320 if (head->backedge_copy_count() != 0)
2321 continue;
2322
2323 // Don't clone head of OSR loop to get correct types in start block.
2324 if (is_osr_flow() && head->start() == start_bci())
2325 continue;
2326
2327 // check _no_ shared head below us
2328 Loop* ch;
2329 for (ch = lp->child(); ch != nullptr && ch->head() != head; ch = ch->sibling());
2330 if (ch != nullptr)
2331 continue;
2332
2333 // Clone head
2334 Block* new_head = head->looping_succ(lp);
2335 Block* clone = clone_loop_head(lp, temp_vector, temp_set);
2336 // Update lp's info
2337 clone->set_loop(lp);
2338 lp->set_head(new_head);
2339 lp->set_tail(clone);
2340 // And move original head into outer loop
2341 head->set_loop(lp->parent());
2342
2343 rslt = true;
2344 }
2345 return rslt;
2346 }
2347
2348 // ------------------------------------------------------------------
2349 // ciTypeFlow::clone_loop_head
2350 //
2351 // Clone lp's head and replace tail's successors with clone.
2352 //
2353 // |
2354 // v
2355 // head <-> body
2356 // |
2357 // v
2358 // exit
2359 //
2360 // new_head
2361 //
2362 // |
2363 // v
2364 // head ----------\
2365 // | |
2366 // | v
2367 // | clone <-> body
2368 // | |
2369 // | /--/
2370 // | |
2371 // v v
2372 // exit
2373 //
2374 ciTypeFlow::Block* ciTypeFlow::clone_loop_head(Loop* lp, StateVector* temp_vector, JsrSet* temp_set) {
2375 Block* head = lp->head();
2376 Block* tail = lp->tail();
2377 if (CITraceTypeFlow) {
2378 tty->print(">> Requesting clone of loop head "); head->print_value_on(tty);
2379 tty->print(" for predecessor "); tail->print_value_on(tty);
2380 tty->cr();
2381 }
2382 Block* clone = block_at(head->start(), head->jsrs(), create_backedge_copy);
2383 assert(clone->backedge_copy_count() == 1, "one backedge copy for all back edges");
2384
2385 assert(!clone->has_pre_order(), "just created");
2386 clone->set_next_pre_order();
2387
2388 // Accumulate profiled count for all backedges that share this loop's head
2389 int total_count = lp->profiled_count();
2390 for (Loop* lp1 = lp->parent(); lp1 != nullptr; lp1 = lp1->parent()) {
2391 for (Loop* lp2 = lp1; lp2 != nullptr; lp2 = lp2->sibling()) {
2392 if (lp2->head() == head && !lp2->tail()->is_backedge_copy()) {
2393 total_count += lp2->profiled_count();
2394 }
2395 }
2396 }
2397 // Have the most frequent ones branch to the clone instead
2398 int count = 0;
2399 int loops_with_shared_head = 0;
2400 Block* latest_tail = tail;
2401 bool done = false;
2402 for (Loop* lp1 = lp; lp1 != nullptr && !done; lp1 = lp1->parent()) {
2403 for (Loop* lp2 = lp1; lp2 != nullptr && !done; lp2 = lp2->sibling()) {
2404 if (lp2->head() == head && !lp2->tail()->is_backedge_copy()) {
2405 count += lp2->profiled_count();
2406 if (lp2->tail()->post_order() < latest_tail->post_order()) {
2407 latest_tail = lp2->tail();
2408 }
2409 loops_with_shared_head++;
2410 for (SuccIter iter(lp2->tail()); !iter.done(); iter.next()) {
2411 if (iter.succ() == head) {
2412 iter.set_succ(clone);
2413 // Update predecessor information
2414 head->predecessors()->remove(lp2->tail());
2415 clone->predecessors()->append(lp2->tail());
2416 }
2417 }
2418 flow_block(lp2->tail(), temp_vector, temp_set);
2419 if (lp2->head() == lp2->tail()) {
2420 // For self-loops, clone->head becomes clone->clone
2421 flow_block(clone, temp_vector, temp_set);
2422 for (SuccIter iter(clone); !iter.done(); iter.next()) {
2423 if (iter.succ() == lp2->head()) {
2424 iter.set_succ(clone);
2425 // Update predecessor information
2426 lp2->head()->predecessors()->remove(clone);
2427 clone->predecessors()->append(clone);
2428 break;
2429 }
2430 }
2431 }
2432 if (total_count == 0 || count > (total_count * .9)) {
2433 done = true;
2434 }
2435 }
2436 }
2437 }
2438 assert(loops_with_shared_head >= 1, "at least one new");
2439 clone->set_rpo_next(latest_tail->rpo_next());
2440 latest_tail->set_rpo_next(clone);
2441 flow_block(clone, temp_vector, temp_set);
2442
2443 return clone;
2444 }
2445
2446 // ------------------------------------------------------------------
2447 // ciTypeFlow::flow_block
2448 //
2449 // Interpret the effects of the bytecodes on the incoming state
2450 // vector of a basic block. Push the changed state to succeeding
2451 // basic blocks.
2452 void ciTypeFlow::flow_block(ciTypeFlow::Block* block,
2453 ciTypeFlow::StateVector* state,
2454 ciTypeFlow::JsrSet* jsrs) {
2455 if (CITraceTypeFlow) {
2456 tty->print("\n>> ANALYZING BLOCK : ");
2457 tty->cr();
2458 block->print_on(tty);
2459 }
2460 assert(block->has_pre_order(), "pre-order is assigned before 1st flow");
2461
2462 int start = block->start();
2463 int limit = block->limit();
2464 int control = block->control();
2465 if (control != ciBlock::fall_through_bci) {
2466 limit = control;
2467 }
2468
2469 // Grab the state from the current block.
2470 block->copy_state_into(state);
2471 state->def_locals()->clear();
2472
2473 GrowableArray<Block*>* exceptions = block->exceptions();
2474 GrowableArray<ciInstanceKlass*>* exc_klasses = block->exc_klasses();
2475 bool has_exceptions = exceptions->length() > 0;
2476
2477 bool exceptions_used = false;
2478
2479 ciBytecodeStream str(method());
2480 str.reset_to_bci(start);
2481 Bytecodes::Code code;
2482 while ((code = str.next()) != ciBytecodeStream::EOBC() &&
2483 str.cur_bci() < limit) {
2484 // Check for exceptional control flow from this point.
2485 if (has_exceptions && can_trap(str)) {
2486 flow_exceptions(exceptions, exc_klasses, state);
2487 exceptions_used = true;
2488 }
2489 // Apply the effects of the current bytecode to our state.
2490 bool res = state->apply_one_bytecode(&str);
2491
2492 // Watch for bailouts.
2493 if (failing()) return;
2494
2495 if (str.cur_bc() == Bytecodes::_monitorenter) {
2496 block->set_has_monitorenter();
2497 }
2498
2499 if (res) {
2500
2501 // We have encountered a trap. Record it in this block.
2502 block->set_trap(state->trap_bci(), state->trap_index());
2503
2504 if (CITraceTypeFlow) {
2505 tty->print_cr(">> Found trap");
2506 block->print_on(tty);
2507 }
2508
2509 // Save set of locals defined in this block
2510 block->def_locals()->add(state->def_locals());
2511
2512 // Record (no) successors.
2513 block->successors(&str, state, jsrs);
2514
2515 assert(!has_exceptions || exceptions_used, "Not removing exceptions");
2516
2517 // Discontinue interpretation of this Block.
2518 return;
2519 }
2520 }
2521
2522 GrowableArray<Block*>* successors = nullptr;
2523 if (control != ciBlock::fall_through_bci) {
2524 // Check for exceptional control flow from this point.
2525 if (has_exceptions && can_trap(str)) {
2526 flow_exceptions(exceptions, exc_klasses, state);
2527 exceptions_used = true;
2528 }
2529
2530 // Fix the JsrSet to reflect effect of the bytecode.
2531 block->copy_jsrs_into(jsrs);
2532 jsrs->apply_control(this, &str, state);
2533
2534 // Find successor edges based on old state and new JsrSet.
2535 successors = block->successors(&str, state, jsrs);
2536
2537 // Apply the control changes to the state.
2538 state->apply_one_bytecode(&str);
2539 } else {
2540 // Fall through control
2541 successors = block->successors(&str, nullptr, nullptr);
2542 }
2543
2544 // Save set of locals defined in this block
2545 block->def_locals()->add(state->def_locals());
2546
2547 // Remove untaken exception paths
2548 if (!exceptions_used)
2549 exceptions->clear();
2550
2551 // Pass our state to successors.
2552 flow_successors(successors, state);
2553 }
2554
2555 // ------------------------------------------------------------------
2556 // ciTypeFlow::PreOrderLoops::next
2557 //
2558 // Advance to next loop tree using a preorder, left-to-right traversal.
2559 void ciTypeFlow::PreorderLoops::next() {
2560 assert(!done(), "must not be done.");
2561 if (_current->child() != nullptr) {
2562 _current = _current->child();
2563 } else if (_current->sibling() != nullptr) {
2564 _current = _current->sibling();
2565 } else {
2566 while (_current != _root && _current->sibling() == nullptr) {
2567 _current = _current->parent();
2568 }
2569 if (_current == _root) {
2570 _current = nullptr;
2571 assert(done(), "must be done.");
2572 } else {
2573 assert(_current->sibling() != nullptr, "must be more to do");
2574 _current = _current->sibling();
2575 }
2576 }
2577 }
2578
2579 // If the tail is a branch to the head, retrieve how many times that path was taken from profiling
2580 int ciTypeFlow::Loop::profiled_count() {
2581 if (_profiled_count >= 0) {
2582 return _profiled_count;
2583 }
2584 ciMethodData* methodData = outer()->method()->method_data();
2585 if (!methodData->is_mature()) {
2586 _profiled_count = 0;
2587 return 0;
2588 }
2589 ciTypeFlow::Block* tail = this->tail();
2590 if (tail->control() == -1 || tail->has_trap()) {
2591 _profiled_count = 0;
2592 return 0;
2593 }
2594
2595 ciProfileData* data = methodData->bci_to_data(tail->control());
2596
2597 if (data == nullptr || !data->is_JumpData()) {
2598 _profiled_count = 0;
2599 return 0;
2600 }
2601
2602 ciBytecodeStream iter(outer()->method());
2603 iter.reset_to_bci(tail->control());
2604
2605 bool is_an_if = false;
2606 bool wide = false;
2607 Bytecodes::Code bc = iter.next();
2608 switch (bc) {
2609 case Bytecodes::_ifeq:
2610 case Bytecodes::_ifne:
2611 case Bytecodes::_iflt:
2612 case Bytecodes::_ifge:
2613 case Bytecodes::_ifgt:
2614 case Bytecodes::_ifle:
2615 case Bytecodes::_if_icmpeq:
2616 case Bytecodes::_if_icmpne:
2617 case Bytecodes::_if_icmplt:
2618 case Bytecodes::_if_icmpge:
2619 case Bytecodes::_if_icmpgt:
2620 case Bytecodes::_if_icmple:
2621 case Bytecodes::_if_acmpeq:
2622 case Bytecodes::_if_acmpne:
2623 case Bytecodes::_ifnull:
2624 case Bytecodes::_ifnonnull:
2625 is_an_if = true;
2626 break;
2627 case Bytecodes::_goto_w:
2628 case Bytecodes::_jsr_w:
2629 wide = true;
2630 break;
2631 case Bytecodes::_goto:
2632 case Bytecodes::_jsr:
2633 break;
2634 default:
2635 fatal(" invalid bytecode: %s", Bytecodes::name(iter.cur_bc()));
2636 }
2637
2638 GrowableArray<ciTypeFlow::Block*>* succs = tail->successors();
2639
2640 if (!is_an_if) {
2641 assert(((wide ? iter.get_far_dest() : iter.get_dest()) == head()->start()) == (succs->at(ciTypeFlow::GOTO_TARGET) == head()), "branch should lead to loop head");
2642 if (succs->at(ciTypeFlow::GOTO_TARGET) == head()) {
2643 _profiled_count = outer()->method()->scale_count(data->as_JumpData()->taken());
2644 return _profiled_count;
2645 }
2646 } else {
2647 assert((iter.get_dest() == head()->start()) == (succs->at(ciTypeFlow::IF_TAKEN) == head()), "bytecode and CFG not consistent");
2648 assert((tail->limit() == head()->start()) == (succs->at(ciTypeFlow::IF_NOT_TAKEN) == head()), "bytecode and CFG not consistent");
2649 if (succs->at(ciTypeFlow::IF_TAKEN) == head()) {
2650 _profiled_count = outer()->method()->scale_count(data->as_JumpData()->taken());
2651 return _profiled_count;
2652 } else if (succs->at(ciTypeFlow::IF_NOT_TAKEN) == head()) {
2653 _profiled_count = outer()->method()->scale_count(data->as_BranchData()->not_taken());
2654 return _profiled_count;
2655 }
2656 }
2657
2658 _profiled_count = 0;
2659 return _profiled_count;
2660 }
2661
2662 bool ciTypeFlow::Loop::at_insertion_point(Loop* lp, Loop* current) {
2663 int lp_pre_order = lp->head()->pre_order();
2664 if (current->head()->pre_order() < lp_pre_order) {
2665 return true;
2666 } else if (current->head()->pre_order() > lp_pre_order) {
2667 return false;
2668 }
2669 // In the case of a shared head, make the most frequent head/tail (as reported by profiling) the inner loop
2670 if (current->head() == lp->head()) {
2671 int lp_count = lp->profiled_count();
2672 int current_count = current->profiled_count();
2673 if (current_count < lp_count) {
2674 return true;
2675 } else if (current_count > lp_count) {
2676 return false;
2677 }
2678 }
2679 if (current->tail()->pre_order() > lp->tail()->pre_order()) {
2680 return true;
2681 }
2682 return false;
2683 }
2684
2685 // ------------------------------------------------------------------
2686 // ciTypeFlow::Loop::sorted_merge
2687 //
2688 // Merge the branch lp into this branch, sorting on the loop head
2689 // pre_orders. Returns the leaf of the merged branch.
2690 // Child and sibling pointers will be setup later.
2691 // Sort is (looking from leaf towards the root)
2692 // descending on primary key: loop head's pre_order, and
2693 // ascending on secondary key: loop tail's pre_order.
2694 ciTypeFlow::Loop* ciTypeFlow::Loop::sorted_merge(Loop* lp) {
2695 Loop* leaf = this;
2696 Loop* prev = nullptr;
2697 Loop* current = leaf;
2698 while (lp != nullptr) {
2699 int lp_pre_order = lp->head()->pre_order();
2700 // Find insertion point for "lp"
2701 while (current != nullptr) {
2702 if (current == lp) {
2703 return leaf; // Already in list
2704 }
2705 if (at_insertion_point(lp, current)) {
2706 break;
2707 }
2708 prev = current;
2709 current = current->parent();
2710 }
2711 Loop* next_lp = lp->parent(); // Save future list of items to insert
2712 // Insert lp before current
2713 lp->set_parent(current);
2714 if (prev != nullptr) {
2715 prev->set_parent(lp);
2716 } else {
2717 leaf = lp;
2718 }
2719 prev = lp; // Inserted item is new prev[ious]
2720 lp = next_lp; // Next item to insert
2721 }
2722 return leaf;
2723 }
2724
2725 // ------------------------------------------------------------------
2726 // ciTypeFlow::build_loop_tree
2727 //
2728 // Incrementally build loop tree.
2729 void ciTypeFlow::build_loop_tree(Block* blk) {
2730 assert(!blk->is_post_visited(), "precondition");
2731 Loop* innermost = nullptr; // merge of loop tree branches over all successors
2732
2733 for (SuccIter iter(blk); !iter.done(); iter.next()) {
2734 Loop* lp = nullptr;
2735 Block* succ = iter.succ();
2736 if (!succ->is_post_visited()) {
2737 // Found backedge since predecessor post visited, but successor is not
2738 assert(succ->pre_order() <= blk->pre_order(), "should be backedge");
2739
2740 // Create a LoopNode to mark this loop.
2741 lp = new (arena()) Loop(succ, blk);
2742 if (succ->loop() == nullptr)
2743 succ->set_loop(lp);
2744 // succ->loop will be updated to innermost loop on a later call, when blk==succ
2745
2746 } else { // Nested loop
2747 lp = succ->loop();
2748
2749 // If succ is loop head, find outer loop.
2750 while (lp != nullptr && lp->head() == succ) {
2751 lp = lp->parent();
2752 }
2753 if (lp == nullptr) {
2754 // Infinite loop, it's parent is the root
2755 lp = loop_tree_root();
2756 }
2757 }
2758
2759 // Check for irreducible loop.
2760 // Successor has already been visited. If the successor's loop head
2761 // has already been post-visited, then this is another entry into the loop.
2762 while (lp->head()->is_post_visited() && lp != loop_tree_root()) {
2763 _has_irreducible_entry = true;
2764 lp->set_irreducible(succ);
2765 if (!succ->is_on_work_list()) {
2766 // Assume irreducible entries need more data flow
2767 add_to_work_list(succ);
2768 }
2769 Loop* plp = lp->parent();
2770 if (plp == nullptr) {
2771 // This only happens for some irreducible cases. The parent
2772 // will be updated during a later pass.
2773 break;
2774 }
2775 lp = plp;
2776 }
2777
2778 // Merge loop tree branch for all successors.
2779 innermost = innermost == nullptr ? lp : innermost->sorted_merge(lp);
2780
2781 } // end loop
2782
2783 if (innermost == nullptr) {
2784 assert(blk->successors()->length() == 0, "CFG exit");
2785 blk->set_loop(loop_tree_root());
2786 } else if (innermost->head() == blk) {
2787 // If loop header, complete the tree pointers
2788 if (blk->loop() != innermost) {
2789 #ifdef ASSERT
2790 assert(blk->loop()->head() == innermost->head(), "same head");
2791 Loop* dl;
2792 for (dl = innermost; dl != nullptr && dl != blk->loop(); dl = dl->parent());
2793 assert(dl == blk->loop(), "blk->loop() already in innermost list");
2794 #endif
2795 blk->set_loop(innermost);
2796 }
2797 innermost->def_locals()->add(blk->def_locals());
2798 Loop* l = innermost;
2799 Loop* p = l->parent();
2800 while (p && l->head() == blk) {
2801 l->set_sibling(p->child()); // Put self on parents 'next child'
2802 p->set_child(l); // Make self the first child of parent
2803 p->def_locals()->add(l->def_locals());
2804 l = p; // Walk up the parent chain
2805 p = l->parent();
2806 }
2807 } else {
2808 blk->set_loop(innermost);
2809 innermost->def_locals()->add(blk->def_locals());
2810 }
2811 }
2812
2813 // ------------------------------------------------------------------
2814 // ciTypeFlow::Loop::contains
2815 //
2816 // Returns true if lp is nested loop.
2817 bool ciTypeFlow::Loop::contains(ciTypeFlow::Loop* lp) const {
2818 assert(lp != nullptr, "");
2819 if (this == lp || head() == lp->head()) return true;
2820 int depth1 = depth();
2821 int depth2 = lp->depth();
2822 if (depth1 > depth2)
2823 return false;
2824 while (depth1 < depth2) {
2825 depth2--;
2826 lp = lp->parent();
2827 }
2828 return this == lp;
2829 }
2830
2831 // ------------------------------------------------------------------
2832 // ciTypeFlow::Loop::depth
2833 //
2834 // Loop depth
2835 int ciTypeFlow::Loop::depth() const {
2836 int dp = 0;
2837 for (Loop* lp = this->parent(); lp != nullptr; lp = lp->parent())
2838 dp++;
2839 return dp;
2840 }
2841
2842 #ifndef PRODUCT
2843 // ------------------------------------------------------------------
2844 // ciTypeFlow::Loop::print
2845 void ciTypeFlow::Loop::print(outputStream* st, int indent) const {
2846 for (int i = 0; i < indent; i++) st->print(" ");
2847 st->print("%d<-%d %s",
2848 is_root() ? 0 : this->head()->pre_order(),
2849 is_root() ? 0 : this->tail()->pre_order(),
2850 is_irreducible()?" irr":"");
2851 st->print(" defs: ");
2852 def_locals()->print_on(st, _head->outer()->method()->max_locals());
2853 st->cr();
2854 for (Loop* ch = child(); ch != nullptr; ch = ch->sibling())
2855 ch->print(st, indent+2);
2856 }
2857 #endif
2858
2859 // ------------------------------------------------------------------
2860 // ciTypeFlow::df_flow_types
2861 //
2862 // Perform the depth first type flow analysis. Helper for flow_types.
2863 void ciTypeFlow::df_flow_types(Block* start,
2864 bool do_flow,
2865 StateVector* temp_vector,
2866 JsrSet* temp_set) {
2867 int dft_len = 100;
2868 GrowableArray<Block*> stk(dft_len);
2869
2870 ciBlock* dummy = _method->get_method_blocks()->make_dummy_block();
2871 JsrSet* root_set = new JsrSet(0);
2872 Block* root_head = new (arena()) Block(this, dummy, root_set);
2873 Block* root_tail = new (arena()) Block(this, dummy, root_set);
2874 root_head->set_pre_order(0);
2875 root_head->set_post_order(0);
2876 root_tail->set_pre_order(max_jint);
2877 root_tail->set_post_order(max_jint);
2878 set_loop_tree_root(new (arena()) Loop(root_head, root_tail));
2879
2880 stk.push(start);
2881
2882 _next_pre_order = 0; // initialize pre_order counter
2883 _rpo_list = nullptr;
2884 int next_po = 0; // initialize post_order counter
2885
2886 // Compute RPO and the control flow graph
2887 int size;
2888 while ((size = stk.length()) > 0) {
2889 Block* blk = stk.top(); // Leave node on stack
2890 if (!blk->is_visited()) {
2891 // forward arc in graph
2892 assert (!blk->has_pre_order(), "");
2893 blk->set_next_pre_order();
2894
2895 if (_next_pre_order >= (int)Compile::current()->max_node_limit() / 2) {
2896 // Too many basic blocks. Bail out.
2897 // This can happen when try/finally constructs are nested to depth N,
2898 // and there is O(2**N) cloning of jsr bodies. See bug 4697245!
2899 // "MaxNodeLimit / 2" is used because probably the parser will
2900 // generate at least twice that many nodes and bail out.
2901 record_failure("too many basic blocks");
2902 return;
2903 }
2904 if (do_flow) {
2905 flow_block(blk, temp_vector, temp_set);
2906 if (failing()) return; // Watch for bailouts.
2907 }
2908 } else if (!blk->is_post_visited()) {
2909 // cross or back arc
2910 for (SuccIter iter(blk); !iter.done(); iter.next()) {
2911 Block* succ = iter.succ();
2912 if (!succ->is_visited()) {
2913 stk.push(succ);
2914 }
2915 }
2916 if (stk.length() == size) {
2917 // There were no additional children, post visit node now
2918 stk.pop(); // Remove node from stack
2919
2920 build_loop_tree(blk);
2921 blk->set_post_order(next_po++); // Assign post order
2922 prepend_to_rpo_list(blk);
2923 assert(blk->is_post_visited(), "");
2924
2925 if (blk->is_loop_head() && !blk->is_on_work_list()) {
2926 // Assume loop heads need more data flow
2927 add_to_work_list(blk);
2928 }
2929 }
2930 } else {
2931 stk.pop(); // Remove post-visited node from stack
2932 }
2933 }
2934 }
2935
2936 // ------------------------------------------------------------------
2937 // ciTypeFlow::flow_types
2938 //
2939 // Perform the type flow analysis, creating and cloning Blocks as
2940 // necessary.
2941 void ciTypeFlow::flow_types() {
2942 ResourceMark rm;
2943 StateVector* temp_vector = new StateVector(this);
2944 JsrSet* temp_set = new JsrSet(4);
2945
2946 // Create the method entry block.
2947 Block* start = block_at(start_bci(), temp_set);
2948
2949 // Load the initial state into it.
2950 const StateVector* start_state = get_start_state();
2951 if (failing()) return;
2952 start->meet(start_state);
2953
2954 // Depth first visit
2955 df_flow_types(start, true /*do flow*/, temp_vector, temp_set);
2956
2957 if (failing()) return;
2958 assert(_rpo_list == start, "must be start");
2959
2960 // Any loops found?
2961 if (loop_tree_root()->child() != nullptr &&
2962 env()->comp_level() >= CompLevel_full_optimization) {
2963 // Loop optimizations are not performed on Tier1 compiles.
2964
2965 bool changed = clone_loop_heads(temp_vector, temp_set);
2966
2967 // If some loop heads were cloned, recompute postorder and loop tree
2968 if (changed) {
2969 loop_tree_root()->set_child(nullptr);
2970 for (Block* blk = _rpo_list; blk != nullptr;) {
2971 Block* next = blk->rpo_next();
2972 blk->df_init();
2973 blk = next;
2974 }
2975 df_flow_types(start, false /*no flow*/, temp_vector, temp_set);
2976 }
2977 }
2978
2979 if (CITraceTypeFlow) {
2980 tty->print_cr("\nLoop tree");
2981 loop_tree_root()->print();
2982 }
2983
2984 // Continue flow analysis until fixed point reached
2985
2986 debug_only(int max_block = _next_pre_order;)
2987
2988 while (!work_list_empty()) {
2989 Block* blk = work_list_next();
2990 assert (blk->has_post_order(), "post order assigned above");
2991
2992 flow_block(blk, temp_vector, temp_set);
2993
2994 assert (max_block == _next_pre_order, "no new blocks");
2995 assert (!failing(), "no more bailouts");
2996 }
2997 }
2998
2999 // ------------------------------------------------------------------
3000 // ciTypeFlow::map_blocks
3001 //
3002 // Create the block map, which indexes blocks in reverse post-order.
3003 void ciTypeFlow::map_blocks() {
3004 assert(_block_map == nullptr, "single initialization");
3005 int block_ct = _next_pre_order;
3006 _block_map = NEW_ARENA_ARRAY(arena(), Block*, block_ct);
3007 assert(block_ct == block_count(), "");
3008
3009 Block* blk = _rpo_list;
3010 for (int m = 0; m < block_ct; m++) {
3011 int rpo = blk->rpo();
3012 assert(rpo == m, "should be sequential");
3013 _block_map[rpo] = blk;
3014 blk = blk->rpo_next();
3015 }
3016 assert(blk == nullptr, "should be done");
3017
3018 for (int j = 0; j < block_ct; j++) {
3019 assert(_block_map[j] != nullptr, "must not drop any blocks");
3020 Block* block = _block_map[j];
3021 // Remove dead blocks from successor lists:
3022 for (int e = 0; e <= 1; e++) {
3023 GrowableArray<Block*>* l = e? block->exceptions(): block->successors();
3024 for (int k = 0; k < l->length(); k++) {
3025 Block* s = l->at(k);
3026 if (!s->has_post_order()) {
3027 if (CITraceTypeFlow) {
3028 tty->print("Removing dead %s successor of #%d: ", (e? "exceptional": "normal"), block->pre_order());
3029 s->print_value_on(tty);
3030 tty->cr();
3031 }
3032 l->remove(s);
3033 --k;
3034 }
3035 }
3036 }
3037 }
3038 }
3039
3040 // ------------------------------------------------------------------
3041 // ciTypeFlow::get_block_for
3042 //
3043 // Find a block with this ciBlock which has a compatible JsrSet.
3044 // If no such block exists, create it, unless the option is no_create.
3045 // If the option is create_backedge_copy, always create a fresh backedge copy.
3046 ciTypeFlow::Block* ciTypeFlow::get_block_for(int ciBlockIndex, ciTypeFlow::JsrSet* jsrs, CreateOption option) {
3047 Arena* a = arena();
3048 GrowableArray<Block*>* blocks = _idx_to_blocklist[ciBlockIndex];
3049 if (blocks == nullptr) {
3050 // Query only?
3051 if (option == no_create) return nullptr;
3052
3053 // Allocate the growable array.
3054 blocks = new (a) GrowableArray<Block*>(a, 4, 0, nullptr);
3055 _idx_to_blocklist[ciBlockIndex] = blocks;
3056 }
3057
3058 if (option != create_backedge_copy) {
3059 int len = blocks->length();
3060 for (int i = 0; i < len; i++) {
3061 Block* block = blocks->at(i);
3062 if (!block->is_backedge_copy() && block->is_compatible_with(jsrs)) {
3063 return block;
3064 }
3065 }
3066 }
3067
3068 // Query only?
3069 if (option == no_create) return nullptr;
3070
3071 // We did not find a compatible block. Create one.
3072 Block* new_block = new (a) Block(this, _method->get_method_blocks()->block(ciBlockIndex), jsrs);
3073 if (option == create_backedge_copy) new_block->set_backedge_copy(true);
3074 blocks->append(new_block);
3075 return new_block;
3076 }
3077
3078 // ------------------------------------------------------------------
3079 // ciTypeFlow::backedge_copy_count
3080 //
3081 int ciTypeFlow::backedge_copy_count(int ciBlockIndex, ciTypeFlow::JsrSet* jsrs) const {
3082 GrowableArray<Block*>* blocks = _idx_to_blocklist[ciBlockIndex];
3083
3084 if (blocks == nullptr) {
3085 return 0;
3086 }
3087
3088 int count = 0;
3089 int len = blocks->length();
3090 for (int i = 0; i < len; i++) {
3091 Block* block = blocks->at(i);
3092 if (block->is_backedge_copy() && block->is_compatible_with(jsrs)) {
3093 count++;
3094 }
3095 }
3096
3097 return count;
3098 }
3099
3100 // ------------------------------------------------------------------
3101 // ciTypeFlow::do_flow
3102 //
3103 // Perform type inference flow analysis.
3104 void ciTypeFlow::do_flow() {
3105 if (CITraceTypeFlow) {
3106 tty->print_cr("\nPerforming flow analysis on method");
3107 method()->print();
3108 if (is_osr_flow()) tty->print(" at OSR bci %d", start_bci());
3109 tty->cr();
3110 method()->print_codes();
3111 }
3112 if (CITraceTypeFlow) {
3113 tty->print_cr("Initial CI Blocks");
3114 print_on(tty);
3115 }
3116 flow_types();
3117 // Watch for bailouts.
3118 if (failing()) {
3119 return;
3120 }
3121
3122 map_blocks();
3123
3124 if (CIPrintTypeFlow || CITraceTypeFlow) {
3125 rpo_print_on(tty);
3126 }
3127 }
3128
3129 // ------------------------------------------------------------------
3130 // ciTypeFlow::is_dominated_by
3131 //
3132 // Determine if the instruction at bci is dominated by the instruction at dom_bci.
3133 bool ciTypeFlow::is_dominated_by(int bci, int dom_bci) {
3134 assert(!method()->has_jsrs(), "jsrs are not supported");
3135
3136 ResourceMark rm;
3137 JsrSet* jsrs = new ciTypeFlow::JsrSet();
3138 int index = _method->get_method_blocks()->block_containing(bci)->index();
3139 int dom_index = _method->get_method_blocks()->block_containing(dom_bci)->index();
3140 Block* block = get_block_for(index, jsrs, ciTypeFlow::no_create);
3141 Block* dom_block = get_block_for(dom_index, jsrs, ciTypeFlow::no_create);
3142
3143 // Start block dominates all other blocks
3144 if (start_block()->rpo() == dom_block->rpo()) {
3145 return true;
3146 }
3147
3148 // Dominated[i] is true if block i is dominated by dom_block
3149 int num_blocks = block_count();
3150 bool* dominated = NEW_RESOURCE_ARRAY(bool, num_blocks);
3151 for (int i = 0; i < num_blocks; ++i) {
3152 dominated[i] = true;
3153 }
3154 dominated[start_block()->rpo()] = false;
3155
3156 // Iterative dominator algorithm
3157 bool changed = true;
3158 while (changed) {
3159 changed = false;
3160 // Use reverse postorder iteration
3161 for (Block* blk = _rpo_list; blk != nullptr; blk = blk->rpo_next()) {
3162 if (blk->is_start()) {
3163 // Ignore start block
3164 continue;
3165 }
3166 // The block is dominated if it is the dominating block
3167 // itself or if all predecessors are dominated.
3168 int index = blk->rpo();
3169 bool dom = (index == dom_block->rpo());
3170 if (!dom) {
3171 // Check if all predecessors are dominated
3172 dom = true;
3173 for (int i = 0; i < blk->predecessors()->length(); ++i) {
3174 Block* pred = blk->predecessors()->at(i);
3175 if (!dominated[pred->rpo()]) {
3176 dom = false;
3177 break;
3178 }
3179 }
3180 }
3181 // Update dominator information
3182 if (dominated[index] != dom) {
3183 changed = true;
3184 dominated[index] = dom;
3185 }
3186 }
3187 }
3188 // block dominated by dom_block?
3189 return dominated[block->rpo()];
3190 }
3191
3192 // ------------------------------------------------------------------
3193 // ciTypeFlow::record_failure()
3194 // The ciTypeFlow object keeps track of failure reasons separately from the ciEnv.
3195 // This is required because there is not a 1-1 relation between the ciEnv and
3196 // the TypeFlow passes within a compilation task. For example, if the compiler
3197 // is considering inlining a method, it will request a TypeFlow. If that fails,
3198 // the compilation as a whole may continue without the inlining. Some TypeFlow
3199 // requests are not optional; if they fail the requestor is responsible for
3200 // copying the failure reason up to the ciEnv. (See Parse::Parse.)
3201 void ciTypeFlow::record_failure(const char* reason) {
3202 if (env()->log() != nullptr) {
3203 env()->log()->elem("failure reason='%s' phase='typeflow'", reason);
3204 }
3205 if (_failure_reason == nullptr) {
3206 // Record the first failure reason.
3207 _failure_reason = reason;
3208 }
3209 }
3210
3211 ciType* ciTypeFlow::mark_as_null_free(ciType* type) {
3212 // Wrap the type to carry the information that it is null-free
3213 return env()->make_null_free_wrapper(type);
3214 }
3215
3216 #ifndef PRODUCT
3217 void ciTypeFlow::print() const { print_on(tty); }
3218
3219 // ------------------------------------------------------------------
3220 // ciTypeFlow::print_on
3221 void ciTypeFlow::print_on(outputStream* st) const {
3222 // Walk through CI blocks
3223 st->print_cr("********************************************************");
3224 st->print ("TypeFlow for ");
3225 method()->name()->print_symbol_on(st);
3226 int limit_bci = code_size();
3227 st->print_cr(" %d bytes", limit_bci);
3228 ciMethodBlocks* mblks = _method->get_method_blocks();
3229 ciBlock* current = nullptr;
3230 for (int bci = 0; bci < limit_bci; bci++) {
3231 ciBlock* blk = mblks->block_containing(bci);
3232 if (blk != nullptr && blk != current) {
3233 current = blk;
3234 current->print_on(st);
3235
3236 GrowableArray<Block*>* blocks = _idx_to_blocklist[blk->index()];
3237 int num_blocks = (blocks == nullptr) ? 0 : blocks->length();
3238
3239 if (num_blocks == 0) {
3240 st->print_cr(" No Blocks");
3241 } else {
3242 for (int i = 0; i < num_blocks; i++) {
3243 Block* block = blocks->at(i);
3244 block->print_on(st);
3245 }
3246 }
3247 st->print_cr("--------------------------------------------------------");
3248 st->cr();
3249 }
3250 }
3251 st->print_cr("********************************************************");
3252 st->cr();
3253 }
3254
3255 void ciTypeFlow::rpo_print_on(outputStream* st) const {
3256 st->print_cr("********************************************************");
3257 st->print ("TypeFlow for ");
3258 method()->name()->print_symbol_on(st);
3259 int limit_bci = code_size();
3260 st->print_cr(" %d bytes", limit_bci);
3261 for (Block* blk = _rpo_list; blk != nullptr; blk = blk->rpo_next()) {
3262 blk->print_on(st);
3263 st->print_cr("--------------------------------------------------------");
3264 st->cr();
3265 }
3266 st->print_cr("********************************************************");
3267 st->cr();
3268 }
3269 #endif