1 /*
2 * Copyright (c) 2000, 2023, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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23 */
24
25 #include "precompiled.hpp"
26 #include "ci/ciConstant.hpp"
27 #include "ci/ciField.hpp"
28 #include "ci/ciInlineKlass.hpp"
29 #include "ci/ciMethod.hpp"
30 #include "ci/ciMethodData.hpp"
31 #include "ci/ciObjArrayKlass.hpp"
32 #include "ci/ciStreams.hpp"
33 #include "ci/ciTypeArrayKlass.hpp"
34 #include "ci/ciTypeFlow.hpp"
35 #include "compiler/compileLog.hpp"
36 #include "interpreter/bytecode.hpp"
37 #include "interpreter/bytecodes.hpp"
38 #include "memory/allocation.inline.hpp"
39 #include "memory/resourceArea.hpp"
40 #include "oops/oop.inline.hpp"
41 #include "opto/compile.hpp"
42 #include "opto/node.hpp"
43 #include "runtime/deoptimization.hpp"
44 #include "utilities/growableArray.hpp"
45
46 // ciTypeFlow::JsrSet
47 //
48 // A JsrSet represents some set of JsrRecords. This class
49 // is used to record a set of all jsr routines which we permit
50 // execution to return (ret) from.
51 //
52 // During abstract interpretation, JsrSets are used to determine
53 // whether two paths which reach a given block are unique, and
54 // should be cloned apart, or are compatible, and should merge
55 // together.
56
57 // ------------------------------------------------------------------
58 // ciTypeFlow::JsrSet::JsrSet
59
60 // Allocate growable array storage in Arena.
61 ciTypeFlow::JsrSet::JsrSet(Arena* arena, int default_len) : _set(arena, default_len, 0, nullptr) {
62 assert(arena != nullptr, "invariant");
63 }
64
65 // Allocate growable array storage in current ResourceArea.
66 ciTypeFlow::JsrSet::JsrSet(int default_len) : _set(default_len, 0, nullptr) {}
67
68 // ------------------------------------------------------------------
69 // ciTypeFlow::JsrSet::copy_into
70 void ciTypeFlow::JsrSet::copy_into(JsrSet* jsrs) {
71 int len = size();
72 jsrs->_set.clear();
73 for (int i = 0; i < len; i++) {
74 jsrs->_set.append(_set.at(i));
75 }
76 }
77
78 // ------------------------------------------------------------------
79 // ciTypeFlow::JsrSet::is_compatible_with
80 //
81 // !!!! MISGIVINGS ABOUT THIS... disregard
82 //
83 // Is this JsrSet compatible with some other JsrSet?
84 //
85 // In set-theoretic terms, a JsrSet can be viewed as a partial function
86 // from entry addresses to return addresses. Two JsrSets A and B are
87 // compatible iff
88 //
89 // For any x,
90 // A(x) defined and B(x) defined implies A(x) == B(x)
91 //
92 // Less formally, two JsrSets are compatible when they have identical
93 // return addresses for any entry addresses they share in common.
94 bool ciTypeFlow::JsrSet::is_compatible_with(JsrSet* other) {
95 // Walk through both sets in parallel. If the same entry address
96 // appears in both sets, then the return address must match for
97 // the sets to be compatible.
98 int size1 = size();
99 int size2 = other->size();
100
101 // Special case. If nothing is on the jsr stack, then there can
102 // be no ret.
103 if (size2 == 0) {
104 return true;
105 } else if (size1 != size2) {
106 return false;
107 } else {
108 for (int i = 0; i < size1; i++) {
109 JsrRecord* record1 = record_at(i);
110 JsrRecord* record2 = other->record_at(i);
111 if (record1->entry_address() != record2->entry_address() ||
112 record1->return_address() != record2->return_address()) {
113 return false;
114 }
115 }
116 return true;
117 }
118
119 #if 0
120 int pos1 = 0;
121 int pos2 = 0;
122 int size1 = size();
123 int size2 = other->size();
124 while (pos1 < size1 && pos2 < size2) {
125 JsrRecord* record1 = record_at(pos1);
126 JsrRecord* record2 = other->record_at(pos2);
127 int entry1 = record1->entry_address();
128 int entry2 = record2->entry_address();
129 if (entry1 < entry2) {
130 pos1++;
131 } else if (entry1 > entry2) {
132 pos2++;
133 } else {
134 if (record1->return_address() == record2->return_address()) {
135 pos1++;
136 pos2++;
137 } else {
138 // These two JsrSets are incompatible.
139 return false;
140 }
141 }
142 }
143 // The two JsrSets agree.
144 return true;
145 #endif
146 }
147
148 // ------------------------------------------------------------------
149 // ciTypeFlow::JsrSet::insert_jsr_record
150 //
151 // Insert the given JsrRecord into the JsrSet, maintaining the order
152 // of the set and replacing any element with the same entry address.
153 void ciTypeFlow::JsrSet::insert_jsr_record(JsrRecord* record) {
154 int len = size();
155 int entry = record->entry_address();
156 int pos = 0;
157 for ( ; pos < len; pos++) {
158 JsrRecord* current = record_at(pos);
159 if (entry == current->entry_address()) {
160 // Stomp over this entry.
161 _set.at_put(pos, record);
162 assert(size() == len, "must be same size");
163 return;
164 } else if (entry < current->entry_address()) {
165 break;
166 }
167 }
168
169 // Insert the record into the list.
170 JsrRecord* swap = record;
171 JsrRecord* temp = nullptr;
172 for ( ; pos < len; pos++) {
173 temp = _set.at(pos);
174 _set.at_put(pos, swap);
175 swap = temp;
176 }
177 _set.append(swap);
178 assert(size() == len+1, "must be larger");
179 }
180
181 // ------------------------------------------------------------------
182 // ciTypeFlow::JsrSet::remove_jsr_record
183 //
184 // Remove the JsrRecord with the given return address from the JsrSet.
185 void ciTypeFlow::JsrSet::remove_jsr_record(int return_address) {
186 int len = size();
187 for (int i = 0; i < len; i++) {
188 if (record_at(i)->return_address() == return_address) {
189 // We have found the proper entry. Remove it from the
190 // JsrSet and exit.
191 for (int j = i + 1; j < len ; j++) {
192 _set.at_put(j - 1, _set.at(j));
193 }
194 _set.trunc_to(len - 1);
195 assert(size() == len-1, "must be smaller");
196 return;
197 }
198 }
199 assert(false, "verify: returning from invalid subroutine");
200 }
201
202 // ------------------------------------------------------------------
203 // ciTypeFlow::JsrSet::apply_control
204 //
205 // Apply the effect of a control-flow bytecode on the JsrSet. The
206 // only bytecodes that modify the JsrSet are jsr and ret.
207 void ciTypeFlow::JsrSet::apply_control(ciTypeFlow* analyzer,
208 ciBytecodeStream* str,
209 ciTypeFlow::StateVector* state) {
210 Bytecodes::Code code = str->cur_bc();
211 if (code == Bytecodes::_jsr) {
212 JsrRecord* record =
213 analyzer->make_jsr_record(str->get_dest(), str->next_bci());
214 insert_jsr_record(record);
215 } else if (code == Bytecodes::_jsr_w) {
216 JsrRecord* record =
217 analyzer->make_jsr_record(str->get_far_dest(), str->next_bci());
218 insert_jsr_record(record);
219 } else if (code == Bytecodes::_ret) {
220 Cell local = state->local(str->get_index());
221 ciType* return_address = state->type_at(local);
222 assert(return_address->is_return_address(), "verify: wrong type");
223 if (size() == 0) {
224 // Ret-state underflow: Hit a ret w/o any previous jsrs. Bail out.
225 // This can happen when a loop is inside a finally clause (4614060).
226 analyzer->record_failure("OSR in finally clause");
227 return;
228 }
229 remove_jsr_record(return_address->as_return_address()->bci());
230 }
231 }
232
233 #ifndef PRODUCT
234 // ------------------------------------------------------------------
235 // ciTypeFlow::JsrSet::print_on
236 void ciTypeFlow::JsrSet::print_on(outputStream* st) const {
237 st->print("{ ");
238 int num_elements = size();
239 if (num_elements > 0) {
240 int i = 0;
241 for( ; i < num_elements - 1; i++) {
242 _set.at(i)->print_on(st);
243 st->print(", ");
244 }
245 _set.at(i)->print_on(st);
246 st->print(" ");
247 }
248 st->print("}");
249 }
250 #endif
251
252 // ciTypeFlow::StateVector
253 //
254 // A StateVector summarizes the type information at some point in
255 // the program.
256
257 // ------------------------------------------------------------------
258 // ciTypeFlow::StateVector::type_meet
259 //
260 // Meet two types.
261 //
262 // The semi-lattice of types use by this analysis are modeled on those
263 // of the verifier. The lattice is as follows:
264 //
265 // top_type() >= all non-extremal types >= bottom_type
266 // and
267 // Every primitive type is comparable only with itself. The meet of
268 // reference types is determined by their kind: instance class,
269 // interface, or array class. The meet of two types of the same
270 // kind is their least common ancestor. The meet of two types of
271 // different kinds is always java.lang.Object.
272 ciType* ciTypeFlow::StateVector::type_meet_internal(ciType* t1, ciType* t2, ciTypeFlow* analyzer) {
273 assert(t1 != t2, "checked in caller");
274 if (t1->equals(top_type())) {
275 return t2;
276 } else if (t2->equals(top_type())) {
277 return t1;
278 }
279 // Unwrap after saving nullness information and handling top meets
280 bool null_free1 = t1->is_null_free();
281 bool null_free2 = t2->is_null_free();
282 if (t1->unwrap() == t2->unwrap() && null_free1 == null_free2) {
283 return t1;
284 }
285 t1 = t1->unwrap();
286 t2 = t2->unwrap();
287
288 if (t1->is_primitive_type() || t2->is_primitive_type()) {
289 // Special case null_type. null_type meet any reference type T
290 // is T. null_type meet null_type is null_type.
291 if (t1->equals(null_type())) {
292 if (!t2->is_primitive_type() || t2->equals(null_type())) {
293 return t2;
294 }
295 } else if (t2->equals(null_type())) {
296 if (!t1->is_primitive_type()) {
297 return t1;
298 }
299 }
300
301 // At least one of the two types is a non-top primitive type.
302 // The other type is not equal to it. Fall to bottom.
303 return bottom_type();
304 }
305
306 // Both types are non-top non-primitive types. That is,
307 // both types are either instanceKlasses or arrayKlasses.
308 ciKlass* object_klass = analyzer->env()->Object_klass();
309 ciKlass* k1 = t1->as_klass();
310 ciKlass* k2 = t2->as_klass();
311 if (k1->equals(object_klass) || k2->equals(object_klass)) {
312 return object_klass;
313 } else if (!k1->is_loaded() || !k2->is_loaded()) {
314 // Unloaded classes fall to java.lang.Object at a merge.
315 return object_klass;
316 } else if (k1->is_interface() != k2->is_interface()) {
317 // When an interface meets a non-interface, we get Object;
318 // This is what the verifier does.
319 return object_klass;
320 } else if (k1->is_array_klass() || k2->is_array_klass()) {
321 // When an array meets a non-array, we get Object.
322 // When (obj/flat)Array meets typeArray, we also get Object.
323 // And when typeArray meets different typeArray, we again get Object.
324 // But when (obj/flat)Array meets (obj/flat)Array, we look carefully at element types.
325 if ((k1->is_obj_array_klass() || k1->is_flat_array_klass()) &&
326 (k2->is_obj_array_klass() || k2->is_flat_array_klass())) {
327 ciType* elem1 = k1->as_array_klass()->element_klass();
328 ciType* elem2 = k2->as_array_klass()->element_klass();
329 ciType* elem = elem1;
330 if (elem1 != elem2) {
331 elem = type_meet_internal(elem1, elem2, analyzer)->as_klass();
332 }
333 // Do an easy shortcut if one type is a super of the other.
334 if (elem == elem1 && !elem->is_inlinetype()) {
335 assert(k1 == ciArrayKlass::make(elem), "shortcut is OK");
336 return k1;
337 } else if (elem == elem2 && !elem->is_inlinetype()) {
338 assert(k2 == ciArrayKlass::make(elem), "shortcut is OK");
339 return k2;
340 } else {
341 return ciArrayKlass::make(elem);
342 }
343 } else {
344 return object_klass;
345 }
346 } else {
347 // Must be two plain old instance klasses.
348 assert(k1->is_instance_klass(), "previous cases handle non-instances");
349 assert(k2->is_instance_klass(), "previous cases handle non-instances");
350 ciType* result = k1->least_common_ancestor(k2);
351 if (null_free1 && null_free2 && result->is_inlinetype()) {
352 result = analyzer->mark_as_null_free(result);
353 }
354 return result;
355 }
356 }
357
358
359 // ------------------------------------------------------------------
360 // ciTypeFlow::StateVector::StateVector
361 //
362 // Build a new state vector
363 ciTypeFlow::StateVector::StateVector(ciTypeFlow* analyzer) {
364 _outer = analyzer;
365 _stack_size = -1;
366 _monitor_count = -1;
367 // Allocate the _types array
368 int max_cells = analyzer->max_cells();
369 _types = (ciType**)analyzer->arena()->Amalloc(sizeof(ciType*) * max_cells);
370 for (int i=0; i<max_cells; i++) {
371 _types[i] = top_type();
372 }
373 _trap_bci = -1;
374 _trap_index = 0;
375 _def_locals.clear();
376 }
377
378
379 // ------------------------------------------------------------------
380 // ciTypeFlow::get_start_state
381 //
382 // Set this vector to the method entry state.
383 const ciTypeFlow::StateVector* ciTypeFlow::get_start_state() {
384 StateVector* state = new StateVector(this);
385 if (is_osr_flow()) {
386 ciTypeFlow* non_osr_flow = method()->get_flow_analysis();
387 if (non_osr_flow->failing()) {
388 record_failure(non_osr_flow->failure_reason());
389 return nullptr;
390 }
391 JsrSet* jsrs = new JsrSet(4);
392 Block* non_osr_block = non_osr_flow->existing_block_at(start_bci(), jsrs);
393 if (non_osr_block == nullptr) {
394 record_failure("cannot reach OSR point");
395 return nullptr;
396 }
397 // load up the non-OSR state at this point
398 non_osr_block->copy_state_into(state);
399 int non_osr_start = non_osr_block->start();
400 if (non_osr_start != start_bci()) {
401 // must flow forward from it
402 if (CITraceTypeFlow) {
403 tty->print_cr(">> Interpreting pre-OSR block %d:", non_osr_start);
404 }
405 Block* block = block_at(non_osr_start, jsrs);
406 assert(block->limit() == start_bci(), "must flow forward to start");
407 flow_block(block, state, jsrs);
408 }
409 return state;
410 // Note: The code below would be an incorrect for an OSR flow,
411 // even if it were possible for an OSR entry point to be at bci zero.
412 }
413 // "Push" the method signature into the first few locals.
414 state->set_stack_size(-max_locals());
415 if (!method()->is_static()) {
416 ciType* holder = method()->holder();
417 if (holder->is_inlinetype()) {
418 // The receiver is null-free
419 holder = mark_as_null_free(holder);
420 }
421 state->push(holder);
422 assert(state->tos() == state->local(0), "");
423 }
424 for (ciSignatureStream str(method()->signature());
425 !str.at_return_type();
426 str.next()) {
427 state->push_translate(str.type());
428 }
429 // Set the rest of the locals to bottom.
430 assert(state->stack_size() <= 0, "stack size should not be strictly positive");
431 while (state->stack_size() < 0) {
432 state->push(state->bottom_type());
433 }
434 // Lock an object, if necessary.
435 state->set_monitor_count(method()->is_synchronized() ? 1 : 0);
436 return state;
437 }
438
439 // ------------------------------------------------------------------
440 // ciTypeFlow::StateVector::copy_into
441 //
442 // Copy our value into some other StateVector
443 void ciTypeFlow::StateVector::copy_into(ciTypeFlow::StateVector* copy)
444 const {
445 copy->set_stack_size(stack_size());
446 copy->set_monitor_count(monitor_count());
447 Cell limit = limit_cell();
448 for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
449 copy->set_type_at(c, type_at(c));
450 }
451 }
452
453 // ------------------------------------------------------------------
454 // ciTypeFlow::StateVector::meet
455 //
456 // Meets this StateVector with another, destructively modifying this
457 // one. Returns true if any modification takes place.
458 bool ciTypeFlow::StateVector::meet(const ciTypeFlow::StateVector* incoming) {
459 if (monitor_count() == -1) {
460 set_monitor_count(incoming->monitor_count());
461 }
462 assert(monitor_count() == incoming->monitor_count(), "monitors must match");
463
464 if (stack_size() == -1) {
465 set_stack_size(incoming->stack_size());
466 Cell limit = limit_cell();
467 #ifdef ASSERT
468 { for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
469 assert(type_at(c) == top_type(), "");
470 } }
471 #endif
472 // Make a simple copy of the incoming state.
473 for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
474 set_type_at(c, incoming->type_at(c));
475 }
476 return true; // it is always different the first time
477 }
478 #ifdef ASSERT
479 if (stack_size() != incoming->stack_size()) {
480 _outer->method()->print_codes();
481 tty->print_cr("!!!! Stack size conflict");
482 tty->print_cr("Current state:");
483 print_on(tty);
484 tty->print_cr("Incoming state:");
485 ((StateVector*)incoming)->print_on(tty);
486 }
487 #endif
488 assert(stack_size() == incoming->stack_size(), "sanity");
489
490 bool different = false;
491 Cell limit = limit_cell();
492 for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
493 ciType* t1 = type_at(c);
494 ciType* t2 = incoming->type_at(c);
495 if (!t1->equals(t2)) {
496 ciType* new_type = type_meet(t1, t2);
497 if (!t1->equals(new_type)) {
498 set_type_at(c, new_type);
499 different = true;
500 }
501 }
502 }
503 return different;
504 }
505
506 // ------------------------------------------------------------------
507 // ciTypeFlow::StateVector::meet_exception
508 //
509 // Meets this StateVector with another, destructively modifying this
510 // one. The incoming state is coming via an exception. Returns true
511 // if any modification takes place.
512 bool ciTypeFlow::StateVector::meet_exception(ciInstanceKlass* exc,
513 const ciTypeFlow::StateVector* incoming) {
514 if (monitor_count() == -1) {
515 set_monitor_count(incoming->monitor_count());
516 }
517 assert(monitor_count() == incoming->monitor_count(), "monitors must match");
518
519 if (stack_size() == -1) {
520 set_stack_size(1);
521 }
522
523 assert(stack_size() == 1, "must have one-element stack");
524
525 bool different = false;
526
527 // Meet locals from incoming array.
528 Cell limit = local(_outer->max_locals()-1);
529 for (Cell c = start_cell(); c <= limit; c = next_cell(c)) {
530 ciType* t1 = type_at(c);
531 ciType* t2 = incoming->type_at(c);
532 if (!t1->equals(t2)) {
533 ciType* new_type = type_meet(t1, t2);
534 if (!t1->equals(new_type)) {
535 set_type_at(c, new_type);
536 different = true;
537 }
538 }
539 }
540
541 // Handle stack separately. When an exception occurs, the
542 // only stack entry is the exception instance.
543 ciType* tos_type = type_at_tos();
544 if (!tos_type->equals(exc)) {
545 ciType* new_type = type_meet(tos_type, exc);
546 if (!tos_type->equals(new_type)) {
547 set_type_at_tos(new_type);
548 different = true;
549 }
550 }
551
552 return different;
553 }
554
555 // ------------------------------------------------------------------
556 // ciTypeFlow::StateVector::push_translate
557 void ciTypeFlow::StateVector::push_translate(ciType* type) {
558 BasicType basic_type = type->basic_type();
559 if (basic_type == T_BOOLEAN || basic_type == T_CHAR ||
560 basic_type == T_BYTE || basic_type == T_SHORT) {
561 push_int();
562 } else {
563 push(type);
564 if (type->is_two_word()) {
565 push(half_type(type));
566 }
567 }
568 }
569
570 // ------------------------------------------------------------------
571 // ciTypeFlow::StateVector::do_aload
572 void ciTypeFlow::StateVector::do_aload(ciBytecodeStream* str) {
573 pop_int();
574 ciArrayKlass* array_klass = pop_objOrFlatArray();
575 if (array_klass == nullptr) {
576 // Did aload on a null reference; push a null and ignore the exception.
577 // This instruction will never continue normally. All we have to do
578 // is report a value that will meet correctly with any downstream
579 // reference types on paths that will truly be executed. This null type
580 // meets with any reference type to yield that same reference type.
581 // (The compiler will generate an unconditional exception here.)
582 push(null_type());
583 return;
584 }
585 if (!array_klass->is_loaded()) {
586 // Only fails for some -Xcomp runs
587 trap(str, array_klass,
588 Deoptimization::make_trap_request
589 (Deoptimization::Reason_unloaded,
590 Deoptimization::Action_reinterpret));
591 return;
592 }
593 ciKlass* element_klass = array_klass->element_klass();
594 if (!element_klass->is_loaded() && element_klass->is_instance_klass()) {
595 Untested("unloaded array element class in ciTypeFlow");
596 trap(str, element_klass,
597 Deoptimization::make_trap_request
598 (Deoptimization::Reason_unloaded,
599 Deoptimization::Action_reinterpret));
600 } else {
601 push_object(element_klass);
602 }
603 }
604
605
606 // ------------------------------------------------------------------
607 // ciTypeFlow::StateVector::do_checkcast
608 void ciTypeFlow::StateVector::do_checkcast(ciBytecodeStream* str) {
609 bool will_link;
610 ciKlass* klass = str->get_klass(will_link);
611 if (!will_link) {
612 // VM's interpreter will not load 'klass' if object is nullptr.
613 // Type flow after this block may still be needed in two situations:
614 // 1) C2 uses do_null_assert() and continues compilation for later blocks
615 // 2) C2 does an OSR compile in a later block (see bug 4778368).
616 pop_object();
617 do_null_assert(klass);
618 } else {
619 ciType* type = pop_value();
620 type = type->unwrap();
621 if (type->is_loaded() && klass->is_loaded() &&
622 type != klass && type->is_subtype_of(klass)) {
623 // Useless cast, propagate more precise type of object
624 klass = type->as_klass();
625 }
626 push_object(klass);
627 }
628 }
629
630 // ------------------------------------------------------------------
631 // ciTypeFlow::StateVector::do_getfield
632 void ciTypeFlow::StateVector::do_getfield(ciBytecodeStream* str) {
633 // could add assert here for type of object.
634 pop_object();
635 do_getstatic(str);
636 }
637
638 // ------------------------------------------------------------------
639 // ciTypeFlow::StateVector::do_getstatic
640 void ciTypeFlow::StateVector::do_getstatic(ciBytecodeStream* str) {
641 bool will_link;
642 ciField* field = str->get_field(will_link);
643 if (!will_link) {
644 trap(str, field->holder(), str->get_field_holder_index());
645 } else {
646 ciType* field_type = field->type();
647 if (field->is_static() && field->is_null_free() &&
648 !field_type->as_instance_klass()->is_initialized()) {
649 // Deoptimize if we load from a static field with an uninitialized inline type
650 // because we need to throw an exception if initialization of the type failed.
651 trap(str, field_type->as_klass(),
652 Deoptimization::make_trap_request
653 (Deoptimization::Reason_unloaded,
654 Deoptimization::Action_reinterpret));
655 return;
656 } else if (!field_type->is_loaded()) {
657 // Normally, we need the field's type to be loaded if we are to
658 // do anything interesting with its value.
659 // We used to do this: trap(str, str->get_field_signature_index());
660 //
661 // There is one good reason not to trap here. Execution can
662 // get past this "getfield" or "getstatic" if the value of
663 // the field is null. As long as the value is null, the class
664 // does not need to be loaded! The compiler must assume that
665 // the value of the unloaded class reference is null; if the code
666 // ever sees a non-null value, loading has occurred.
667 //
668 // This actually happens often enough to be annoying. If the
669 // compiler throws an uncommon trap at this bytecode, you can
670 // get an endless loop of recompilations, when all the code
671 // needs to do is load a series of null values. Also, a trap
672 // here can make an OSR entry point unreachable, triggering the
673 // assert on non_osr_block in ciTypeFlow::get_start_state.
674 // (See bug 4379915.)
675 do_null_assert(field_type->as_klass());
676 } else {
677 if (field->is_null_free()) {
678 field_type = outer()->mark_as_null_free(field_type);
679 }
680 push_translate(field_type);
681 }
682 }
683 }
684
685 // ------------------------------------------------------------------
686 // ciTypeFlow::StateVector::do_invoke
687 void ciTypeFlow::StateVector::do_invoke(ciBytecodeStream* str,
688 bool has_receiver) {
689 bool will_link;
690 ciSignature* declared_signature = nullptr;
691 ciMethod* callee = str->get_method(will_link, &declared_signature);
692 assert(declared_signature != nullptr, "cannot be null");
693 if (!will_link) {
694 // We weren't able to find the method.
695 if (str->cur_bc() == Bytecodes::_invokedynamic) {
696 trap(str, nullptr,
697 Deoptimization::make_trap_request
698 (Deoptimization::Reason_uninitialized,
699 Deoptimization::Action_reinterpret));
700 } else {
701 ciKlass* unloaded_holder = callee->holder();
702 trap(str, unloaded_holder, str->get_method_holder_index());
703 }
704 } else {
705 // We are using the declared signature here because it might be
706 // different from the callee signature (Cf. invokedynamic and
707 // invokehandle).
708 ciSignatureStream sigstr(declared_signature);
709 const int arg_size = declared_signature->size();
710 const int stack_base = stack_size() - arg_size;
711 int i = 0;
712 for( ; !sigstr.at_return_type(); sigstr.next()) {
713 ciType* type = sigstr.type();
714 ciType* stack_type = type_at(stack(stack_base + i++));
715 // Do I want to check this type?
716 // assert(stack_type->is_subtype_of(type), "bad type for field value");
717 if (type->is_two_word()) {
718 ciType* stack_type2 = type_at(stack(stack_base + i++));
719 assert(stack_type2->equals(half_type(type)), "must be 2nd half");
720 }
721 }
722 assert(arg_size == i, "must match");
723 for (int j = 0; j < arg_size; j++) {
724 pop();
725 }
726 if (has_receiver) {
727 // Check this?
728 pop_object();
729 }
730 assert(!sigstr.is_done(), "must have return type");
731 ciType* return_type = sigstr.type();
732 if (!return_type->is_void()) {
733 if (!return_type->is_loaded()) {
734 // As in do_getstatic(), generally speaking, we need the return type to
735 // be loaded if we are to do anything interesting with its value.
736 // We used to do this: trap(str, str->get_method_signature_index());
737 //
738 // We do not trap here since execution can get past this invoke if
739 // the return value is null. As long as the value is null, the class
740 // does not need to be loaded! The compiler must assume that
741 // the value of the unloaded class reference is null; if the code
742 // ever sees a non-null value, loading has occurred.
743 //
744 // See do_getstatic() for similar explanation, as well as bug 4684993.
745 if (InlineTypeReturnedAsFields) {
746 // Return might be in scalarized form but we can't handle it because we
747 // don't know the type. This can happen due to a missing preload attribute.
748 // TODO 8284443 Use PhaseMacroExpand::expand_mh_intrinsic_return for this
749 trap(str, nullptr,
750 Deoptimization::make_trap_request
751 (Deoptimization::Reason_uninitialized,
752 Deoptimization::Action_reinterpret));
753 } else {
754 do_null_assert(return_type->as_klass());
755 }
756 } else {
757 push_translate(return_type);
758 }
759 }
760 }
761 }
762
763 // ------------------------------------------------------------------
764 // ciTypeFlow::StateVector::do_jsr
765 void ciTypeFlow::StateVector::do_jsr(ciBytecodeStream* str) {
766 push(ciReturnAddress::make(str->next_bci()));
767 }
768
769 // ------------------------------------------------------------------
770 // ciTypeFlow::StateVector::do_ldc
771 void ciTypeFlow::StateVector::do_ldc(ciBytecodeStream* str) {
772 if (str->is_in_error()) {
773 trap(str, nullptr, Deoptimization::make_trap_request(Deoptimization::Reason_unhandled,
774 Deoptimization::Action_none));
775 return;
776 }
777 ciConstant con = str->get_constant();
778 if (con.is_valid()) {
779 int cp_index = str->get_constant_pool_index();
780 if (!con.is_loaded()) {
781 trap(str, nullptr, Deoptimization::make_trap_request(Deoptimization::Reason_unloaded,
782 Deoptimization::Action_reinterpret,
783 cp_index));
784 return;
785 }
786 BasicType basic_type = str->get_basic_type_for_constant_at(cp_index);
787 if (is_reference_type(basic_type)) {
788 ciObject* obj = con.as_object();
789 if (obj->is_null_object()) {
790 push_null();
791 } else {
792 assert(obj->is_instance() || obj->is_array(), "must be java_mirror of klass");
793 ciType* type = obj->klass();
794 if (type->is_inlinetype()) {
795 type = outer()->mark_as_null_free(type);
796 }
797 push(type);
798 }
799 } else {
800 assert(basic_type == con.basic_type() || con.basic_type() == T_OBJECT,
801 "not a boxed form: %s vs %s", type2name(basic_type), type2name(con.basic_type()));
802 push_translate(ciType::make(basic_type));
803 }
804 } else {
805 // OutOfMemoryError in the CI while loading a String constant.
806 push_null();
807 outer()->record_failure("ldc did not link");
808 }
809 }
810
811 // ------------------------------------------------------------------
812 // ciTypeFlow::StateVector::do_multianewarray
813 void ciTypeFlow::StateVector::do_multianewarray(ciBytecodeStream* str) {
814 int dimensions = str->get_dimensions();
815 bool will_link;
816 ciArrayKlass* array_klass = str->get_klass(will_link)->as_array_klass();
817 if (!will_link) {
818 trap(str, array_klass, str->get_klass_index());
819 } else {
820 for (int i = 0; i < dimensions; i++) {
821 pop_int();
822 }
823 push_object(array_klass);
824 }
825 }
826
827 // ------------------------------------------------------------------
828 // ciTypeFlow::StateVector::do_new
829 void ciTypeFlow::StateVector::do_new(ciBytecodeStream* str) {
830 bool will_link;
831 ciKlass* klass = str->get_klass(will_link);
832 if (!will_link || str->is_unresolved_klass()) {
833 trap(str, klass, str->get_klass_index());
834 } else {
835 push_object(klass);
836 }
837 }
838
839 // ------------------------------------------------------------------
840 // ciTypeFlow::StateVector::do_newarray
841 void ciTypeFlow::StateVector::do_newarray(ciBytecodeStream* str) {
842 pop_int();
843 ciKlass* klass = ciTypeArrayKlass::make((BasicType)str->get_index());
844 push_object(klass);
845 }
846
847 // ------------------------------------------------------------------
848 // ciTypeFlow::StateVector::do_putfield
849 void ciTypeFlow::StateVector::do_putfield(ciBytecodeStream* str) {
850 do_putstatic(str);
851 if (_trap_bci != -1) return; // unloaded field holder, etc.
852 // could add assert here for type of object.
853 pop_object();
854 }
855
856 // ------------------------------------------------------------------
857 // ciTypeFlow::StateVector::do_putstatic
858 void ciTypeFlow::StateVector::do_putstatic(ciBytecodeStream* str) {
859 bool will_link;
860 ciField* field = str->get_field(will_link);
861 if (!will_link) {
862 trap(str, field->holder(), str->get_field_holder_index());
863 } else {
864 ciType* field_type = field->type();
865 ciType* type = pop_value();
866 // Do I want to check this type?
867 // assert(type->is_subtype_of(field_type), "bad type for field value");
868 if (field_type->is_two_word()) {
869 ciType* type2 = pop_value();
870 assert(type2->is_two_word(), "must be 2nd half");
871 assert(type == half_type(type2), "must be 2nd half");
872 }
873 }
874 }
875
876 // ------------------------------------------------------------------
877 // ciTypeFlow::StateVector::do_ret
878 void ciTypeFlow::StateVector::do_ret(ciBytecodeStream* str) {
879 Cell index = local(str->get_index());
880
881 ciType* address = type_at(index);
882 assert(address->is_return_address(), "bad return address");
883 set_type_at(index, bottom_type());
884 }
885
886 // ------------------------------------------------------------------
887 // ciTypeFlow::StateVector::trap
888 //
889 // Stop interpretation of this path with a trap.
890 void ciTypeFlow::StateVector::trap(ciBytecodeStream* str, ciKlass* klass, int index) {
891 _trap_bci = str->cur_bci();
892 _trap_index = index;
893
894 // Log information about this trap:
895 CompileLog* log = outer()->env()->log();
896 if (log != nullptr) {
897 int mid = log->identify(outer()->method());
898 int kid = (klass == nullptr)? -1: log->identify(klass);
899 log->begin_elem("uncommon_trap method='%d' bci='%d'", mid, str->cur_bci());
900 char buf[100];
901 log->print(" %s", Deoptimization::format_trap_request(buf, sizeof(buf),
902 index));
903 if (kid >= 0)
904 log->print(" klass='%d'", kid);
905 log->end_elem();
906 }
907 }
908
909 // ------------------------------------------------------------------
910 // ciTypeFlow::StateVector::do_null_assert
911 // Corresponds to graphKit::do_null_assert.
912 void ciTypeFlow::StateVector::do_null_assert(ciKlass* unloaded_klass) {
913 if (unloaded_klass->is_loaded()) {
914 // We failed to link, but we can still compute with this class,
915 // since it is loaded somewhere. The compiler will uncommon_trap
916 // if the object is not null, but the typeflow pass can not assume
917 // that the object will be null, otherwise it may incorrectly tell
918 // the parser that an object is known to be null. 4761344, 4807707
919 push_object(unloaded_klass);
920 } else {
921 // The class is not loaded anywhere. It is safe to model the
922 // null in the typestates, because we can compile in a null check
923 // which will deoptimize us if someone manages to load the
924 // class later.
925 push_null();
926 }
927 }
928
929
930 // ------------------------------------------------------------------
931 // ciTypeFlow::StateVector::apply_one_bytecode
932 //
933 // Apply the effect of one bytecode to this StateVector
934 bool ciTypeFlow::StateVector::apply_one_bytecode(ciBytecodeStream* str) {
935 _trap_bci = -1;
936 _trap_index = 0;
937
938 if (CITraceTypeFlow) {
939 tty->print_cr(">> Interpreting bytecode %d:%s", str->cur_bci(),
940 Bytecodes::name(str->cur_bc()));
941 }
942
943 switch(str->cur_bc()) {
944 case Bytecodes::_aaload: do_aload(str); break;
945
946 case Bytecodes::_aastore:
947 {
948 pop_object();
949 pop_int();
950 pop_objOrFlatArray();
951 break;
952 }
953 case Bytecodes::_aconst_null:
954 {
955 push_null();
956 break;
957 }
958 case Bytecodes::_aload: load_local_object(str->get_index()); break;
959 case Bytecodes::_aload_0: load_local_object(0); break;
960 case Bytecodes::_aload_1: load_local_object(1); break;
961 case Bytecodes::_aload_2: load_local_object(2); break;
962 case Bytecodes::_aload_3: load_local_object(3); break;
963
964 case Bytecodes::_anewarray:
965 {
966 pop_int();
967 bool will_link;
968 ciKlass* element_klass = str->get_klass(will_link);
969 if (!will_link) {
970 trap(str, element_klass, str->get_klass_index());
971 } else {
972 push_object(ciArrayKlass::make(element_klass));
973 }
974 break;
975 }
976 case Bytecodes::_areturn:
977 case Bytecodes::_ifnonnull:
978 case Bytecodes::_ifnull:
979 {
980 pop_object();
981 break;
982 }
983 case Bytecodes::_monitorenter:
984 {
985 pop_object();
986 set_monitor_count(monitor_count() + 1);
987 break;
988 }
989 case Bytecodes::_monitorexit:
990 {
991 pop_object();
992 assert(monitor_count() > 0, "must be a monitor to exit from");
993 set_monitor_count(monitor_count() - 1);
994 break;
995 }
996 case Bytecodes::_arraylength:
997 {
998 pop_array();
999 push_int();
1000 break;
1001 }
1002 case Bytecodes::_astore: store_local_object(str->get_index()); break;
1003 case Bytecodes::_astore_0: store_local_object(0); break;
1004 case Bytecodes::_astore_1: store_local_object(1); break;
1005 case Bytecodes::_astore_2: store_local_object(2); break;
1006 case Bytecodes::_astore_3: store_local_object(3); break;
1007
1008 case Bytecodes::_athrow:
1009 {
1010 NEEDS_CLEANUP;
1011 pop_object();
1012 break;
1013 }
1014 case Bytecodes::_baload:
1015 case Bytecodes::_caload:
1016 case Bytecodes::_iaload:
1017 case Bytecodes::_saload:
1018 {
1019 pop_int();
1020 ciTypeArrayKlass* array_klass = pop_typeArray();
1021 // Put assert here for right type?
1022 push_int();
1023 break;
1024 }
1025 case Bytecodes::_bastore:
1026 case Bytecodes::_castore:
1027 case Bytecodes::_iastore:
1028 case Bytecodes::_sastore:
1029 {
1030 pop_int();
1031 pop_int();
1032 pop_typeArray();
1033 // assert here?
1034 break;
1035 }
1036 case Bytecodes::_bipush:
1037 case Bytecodes::_iconst_m1:
1038 case Bytecodes::_iconst_0:
1039 case Bytecodes::_iconst_1:
1040 case Bytecodes::_iconst_2:
1041 case Bytecodes::_iconst_3:
1042 case Bytecodes::_iconst_4:
1043 case Bytecodes::_iconst_5:
1044 case Bytecodes::_sipush:
1045 {
1046 push_int();
1047 break;
1048 }
1049 case Bytecodes::_checkcast: do_checkcast(str); break;
1050
1051 case Bytecodes::_d2f:
1052 {
1053 pop_double();
1054 push_float();
1055 break;
1056 }
1057 case Bytecodes::_d2i:
1058 {
1059 pop_double();
1060 push_int();
1061 break;
1062 }
1063 case Bytecodes::_d2l:
1064 {
1065 pop_double();
1066 push_long();
1067 break;
1068 }
1069 case Bytecodes::_dadd:
1070 case Bytecodes::_ddiv:
1071 case Bytecodes::_dmul:
1072 case Bytecodes::_drem:
1073 case Bytecodes::_dsub:
1074 {
1075 pop_double();
1076 pop_double();
1077 push_double();
1078 break;
1079 }
1080 case Bytecodes::_daload:
1081 {
1082 pop_int();
1083 ciTypeArrayKlass* array_klass = pop_typeArray();
1084 // Put assert here for right type?
1085 push_double();
1086 break;
1087 }
1088 case Bytecodes::_dastore:
1089 {
1090 pop_double();
1091 pop_int();
1092 pop_typeArray();
1093 // assert here?
1094 break;
1095 }
1096 case Bytecodes::_dcmpg:
1097 case Bytecodes::_dcmpl:
1098 {
1099 pop_double();
1100 pop_double();
1101 push_int();
1102 break;
1103 }
1104 case Bytecodes::_dconst_0:
1105 case Bytecodes::_dconst_1:
1106 {
1107 push_double();
1108 break;
1109 }
1110 case Bytecodes::_dload: load_local_double(str->get_index()); break;
1111 case Bytecodes::_dload_0: load_local_double(0); break;
1112 case Bytecodes::_dload_1: load_local_double(1); break;
1113 case Bytecodes::_dload_2: load_local_double(2); break;
1114 case Bytecodes::_dload_3: load_local_double(3); break;
1115
1116 case Bytecodes::_dneg:
1117 {
1118 pop_double();
1119 push_double();
1120 break;
1121 }
1122 case Bytecodes::_dreturn:
1123 {
1124 pop_double();
1125 break;
1126 }
1127 case Bytecodes::_dstore: store_local_double(str->get_index()); break;
1128 case Bytecodes::_dstore_0: store_local_double(0); break;
1129 case Bytecodes::_dstore_1: store_local_double(1); break;
1130 case Bytecodes::_dstore_2: store_local_double(2); break;
1131 case Bytecodes::_dstore_3: store_local_double(3); break;
1132
1133 case Bytecodes::_dup:
1134 {
1135 push(type_at_tos());
1136 break;
1137 }
1138 case Bytecodes::_dup_x1:
1139 {
1140 ciType* value1 = pop_value();
1141 ciType* value2 = pop_value();
1142 push(value1);
1143 push(value2);
1144 push(value1);
1145 break;
1146 }
1147 case Bytecodes::_dup_x2:
1148 {
1149 ciType* value1 = pop_value();
1150 ciType* value2 = pop_value();
1151 ciType* value3 = pop_value();
1152 push(value1);
1153 push(value3);
1154 push(value2);
1155 push(value1);
1156 break;
1157 }
1158 case Bytecodes::_dup2:
1159 {
1160 ciType* value1 = pop_value();
1161 ciType* value2 = pop_value();
1162 push(value2);
1163 push(value1);
1164 push(value2);
1165 push(value1);
1166 break;
1167 }
1168 case Bytecodes::_dup2_x1:
1169 {
1170 ciType* value1 = pop_value();
1171 ciType* value2 = pop_value();
1172 ciType* value3 = pop_value();
1173 push(value2);
1174 push(value1);
1175 push(value3);
1176 push(value2);
1177 push(value1);
1178 break;
1179 }
1180 case Bytecodes::_dup2_x2:
1181 {
1182 ciType* value1 = pop_value();
1183 ciType* value2 = pop_value();
1184 ciType* value3 = pop_value();
1185 ciType* value4 = pop_value();
1186 push(value2);
1187 push(value1);
1188 push(value4);
1189 push(value3);
1190 push(value2);
1191 push(value1);
1192 break;
1193 }
1194 case Bytecodes::_f2d:
1195 {
1196 pop_float();
1197 push_double();
1198 break;
1199 }
1200 case Bytecodes::_f2i:
1201 {
1202 pop_float();
1203 push_int();
1204 break;
1205 }
1206 case Bytecodes::_f2l:
1207 {
1208 pop_float();
1209 push_long();
1210 break;
1211 }
1212 case Bytecodes::_fadd:
1213 case Bytecodes::_fdiv:
1214 case Bytecodes::_fmul:
1215 case Bytecodes::_frem:
1216 case Bytecodes::_fsub:
1217 {
1218 pop_float();
1219 pop_float();
1220 push_float();
1221 break;
1222 }
1223 case Bytecodes::_faload:
1224 {
1225 pop_int();
1226 ciTypeArrayKlass* array_klass = pop_typeArray();
1227 // Put assert here.
1228 push_float();
1229 break;
1230 }
1231 case Bytecodes::_fastore:
1232 {
1233 pop_float();
1234 pop_int();
1235 ciTypeArrayKlass* array_klass = pop_typeArray();
1236 // Put assert here.
1237 break;
1238 }
1239 case Bytecodes::_fcmpg:
1240 case Bytecodes::_fcmpl:
1241 {
1242 pop_float();
1243 pop_float();
1244 push_int();
1245 break;
1246 }
1247 case Bytecodes::_fconst_0:
1248 case Bytecodes::_fconst_1:
1249 case Bytecodes::_fconst_2:
1250 {
1251 push_float();
1252 break;
1253 }
1254 case Bytecodes::_fload: load_local_float(str->get_index()); break;
1255 case Bytecodes::_fload_0: load_local_float(0); break;
1256 case Bytecodes::_fload_1: load_local_float(1); break;
1257 case Bytecodes::_fload_2: load_local_float(2); break;
1258 case Bytecodes::_fload_3: load_local_float(3); break;
1259
1260 case Bytecodes::_fneg:
1261 {
1262 pop_float();
1263 push_float();
1264 break;
1265 }
1266 case Bytecodes::_freturn:
1267 {
1268 pop_float();
1269 break;
1270 }
1271 case Bytecodes::_fstore: store_local_float(str->get_index()); break;
1272 case Bytecodes::_fstore_0: store_local_float(0); break;
1273 case Bytecodes::_fstore_1: store_local_float(1); break;
1274 case Bytecodes::_fstore_2: store_local_float(2); break;
1275 case Bytecodes::_fstore_3: store_local_float(3); break;
1276
1277 case Bytecodes::_getfield: do_getfield(str); break;
1278 case Bytecodes::_getstatic: do_getstatic(str); break;
1279
1280 case Bytecodes::_goto:
1281 case Bytecodes::_goto_w:
1282 case Bytecodes::_nop:
1283 case Bytecodes::_return:
1284 {
1285 // do nothing.
1286 break;
1287 }
1288 case Bytecodes::_i2b:
1289 case Bytecodes::_i2c:
1290 case Bytecodes::_i2s:
1291 case Bytecodes::_ineg:
1292 {
1293 pop_int();
1294 push_int();
1295 break;
1296 }
1297 case Bytecodes::_i2d:
1298 {
1299 pop_int();
1300 push_double();
1301 break;
1302 }
1303 case Bytecodes::_i2f:
1304 {
1305 pop_int();
1306 push_float();
1307 break;
1308 }
1309 case Bytecodes::_i2l:
1310 {
1311 pop_int();
1312 push_long();
1313 break;
1314 }
1315 case Bytecodes::_iadd:
1316 case Bytecodes::_iand:
1317 case Bytecodes::_idiv:
1318 case Bytecodes::_imul:
1319 case Bytecodes::_ior:
1320 case Bytecodes::_irem:
1321 case Bytecodes::_ishl:
1322 case Bytecodes::_ishr:
1323 case Bytecodes::_isub:
1324 case Bytecodes::_iushr:
1325 case Bytecodes::_ixor:
1326 {
1327 pop_int();
1328 pop_int();
1329 push_int();
1330 break;
1331 }
1332 case Bytecodes::_if_acmpeq:
1333 case Bytecodes::_if_acmpne:
1334 {
1335 pop_object();
1336 pop_object();
1337 break;
1338 }
1339 case Bytecodes::_if_icmpeq:
1340 case Bytecodes::_if_icmpge:
1341 case Bytecodes::_if_icmpgt:
1342 case Bytecodes::_if_icmple:
1343 case Bytecodes::_if_icmplt:
1344 case Bytecodes::_if_icmpne:
1345 {
1346 pop_int();
1347 pop_int();
1348 break;
1349 }
1350 case Bytecodes::_ifeq:
1351 case Bytecodes::_ifle:
1352 case Bytecodes::_iflt:
1353 case Bytecodes::_ifge:
1354 case Bytecodes::_ifgt:
1355 case Bytecodes::_ifne:
1356 case Bytecodes::_ireturn:
1357 case Bytecodes::_lookupswitch:
1358 case Bytecodes::_tableswitch:
1359 {
1360 pop_int();
1361 break;
1362 }
1363 case Bytecodes::_iinc:
1364 {
1365 int lnum = str->get_index();
1366 check_int(local(lnum));
1367 store_to_local(lnum);
1368 break;
1369 }
1370 case Bytecodes::_iload: load_local_int(str->get_index()); break;
1371 case Bytecodes::_iload_0: load_local_int(0); break;
1372 case Bytecodes::_iload_1: load_local_int(1); break;
1373 case Bytecodes::_iload_2: load_local_int(2); break;
1374 case Bytecodes::_iload_3: load_local_int(3); break;
1375
1376 case Bytecodes::_instanceof:
1377 {
1378 // Check for uncommon trap:
1379 do_checkcast(str);
1380 pop_object();
1381 push_int();
1382 break;
1383 }
1384 case Bytecodes::_invokeinterface: do_invoke(str, true); break;
1385 case Bytecodes::_invokespecial: do_invoke(str, true); break;
1386 case Bytecodes::_invokestatic: do_invoke(str, false); break;
1387 case Bytecodes::_invokevirtual: do_invoke(str, true); break;
1388 case Bytecodes::_invokedynamic: do_invoke(str, false); break;
1389
1390 case Bytecodes::_istore: store_local_int(str->get_index()); break;
1391 case Bytecodes::_istore_0: store_local_int(0); break;
1392 case Bytecodes::_istore_1: store_local_int(1); break;
1393 case Bytecodes::_istore_2: store_local_int(2); break;
1394 case Bytecodes::_istore_3: store_local_int(3); break;
1395
1396 case Bytecodes::_jsr:
1397 case Bytecodes::_jsr_w: do_jsr(str); break;
1398
1399 case Bytecodes::_l2d:
1400 {
1401 pop_long();
1402 push_double();
1403 break;
1404 }
1405 case Bytecodes::_l2f:
1406 {
1407 pop_long();
1408 push_float();
1409 break;
1410 }
1411 case Bytecodes::_l2i:
1412 {
1413 pop_long();
1414 push_int();
1415 break;
1416 }
1417 case Bytecodes::_ladd:
1418 case Bytecodes::_land:
1419 case Bytecodes::_ldiv:
1420 case Bytecodes::_lmul:
1421 case Bytecodes::_lor:
1422 case Bytecodes::_lrem:
1423 case Bytecodes::_lsub:
1424 case Bytecodes::_lxor:
1425 {
1426 pop_long();
1427 pop_long();
1428 push_long();
1429 break;
1430 }
1431 case Bytecodes::_laload:
1432 {
1433 pop_int();
1434 ciTypeArrayKlass* array_klass = pop_typeArray();
1435 // Put assert here for right type?
1436 push_long();
1437 break;
1438 }
1439 case Bytecodes::_lastore:
1440 {
1441 pop_long();
1442 pop_int();
1443 pop_typeArray();
1444 // assert here?
1445 break;
1446 }
1447 case Bytecodes::_lcmp:
1448 {
1449 pop_long();
1450 pop_long();
1451 push_int();
1452 break;
1453 }
1454 case Bytecodes::_lconst_0:
1455 case Bytecodes::_lconst_1:
1456 {
1457 push_long();
1458 break;
1459 }
1460 case Bytecodes::_ldc:
1461 case Bytecodes::_ldc_w:
1462 case Bytecodes::_ldc2_w:
1463 {
1464 do_ldc(str);
1465 break;
1466 }
1467
1468 case Bytecodes::_lload: load_local_long(str->get_index()); break;
1469 case Bytecodes::_lload_0: load_local_long(0); break;
1470 case Bytecodes::_lload_1: load_local_long(1); break;
1471 case Bytecodes::_lload_2: load_local_long(2); break;
1472 case Bytecodes::_lload_3: load_local_long(3); break;
1473
1474 case Bytecodes::_lneg:
1475 {
1476 pop_long();
1477 push_long();
1478 break;
1479 }
1480 case Bytecodes::_lreturn:
1481 {
1482 pop_long();
1483 break;
1484 }
1485 case Bytecodes::_lshl:
1486 case Bytecodes::_lshr:
1487 case Bytecodes::_lushr:
1488 {
1489 pop_int();
1490 pop_long();
1491 push_long();
1492 break;
1493 }
1494 case Bytecodes::_lstore: store_local_long(str->get_index()); break;
1495 case Bytecodes::_lstore_0: store_local_long(0); break;
1496 case Bytecodes::_lstore_1: store_local_long(1); break;
1497 case Bytecodes::_lstore_2: store_local_long(2); break;
1498 case Bytecodes::_lstore_3: store_local_long(3); break;
1499
1500 case Bytecodes::_multianewarray: do_multianewarray(str); break;
1501
1502 case Bytecodes::_new: do_new(str); break;
1503
1504 case Bytecodes::_newarray: do_newarray(str); break;
1505
1506 case Bytecodes::_pop:
1507 {
1508 pop();
1509 break;
1510 }
1511 case Bytecodes::_pop2:
1512 {
1513 pop();
1514 pop();
1515 break;
1516 }
1517
1518 case Bytecodes::_putfield: do_putfield(str); break;
1519 case Bytecodes::_putstatic: do_putstatic(str); break;
1520
1521 case Bytecodes::_ret: do_ret(str); break;
1522
1523 case Bytecodes::_swap:
1524 {
1525 ciType* value1 = pop_value();
1526 ciType* value2 = pop_value();
1527 push(value1);
1528 push(value2);
1529 break;
1530 }
1531
1532 case Bytecodes::_wide:
1533 default:
1534 {
1535 // The iterator should skip this.
1536 ShouldNotReachHere();
1537 break;
1538 }
1539 }
1540
1541 if (CITraceTypeFlow) {
1542 print_on(tty);
1543 }
1544
1545 return (_trap_bci != -1);
1546 }
1547
1548 #ifndef PRODUCT
1549 // ------------------------------------------------------------------
1550 // ciTypeFlow::StateVector::print_cell_on
1551 void ciTypeFlow::StateVector::print_cell_on(outputStream* st, Cell c) const {
1552 ciType* type = type_at(c)->unwrap();
1553 if (type == top_type()) {
1554 st->print("top");
1555 } else if (type == bottom_type()) {
1556 st->print("bottom");
1557 } else if (type == null_type()) {
1558 st->print("null");
1559 } else if (type == long2_type()) {
1560 st->print("long2");
1561 } else if (type == double2_type()) {
1562 st->print("double2");
1563 } else if (is_int(type)) {
1564 st->print("int");
1565 } else if (is_long(type)) {
1566 st->print("long");
1567 } else if (is_float(type)) {
1568 st->print("float");
1569 } else if (is_double(type)) {
1570 st->print("double");
1571 } else if (type->is_return_address()) {
1572 st->print("address(%d)", type->as_return_address()->bci());
1573 } else {
1574 if (type->is_klass()) {
1575 type->as_klass()->name()->print_symbol_on(st);
1576 } else {
1577 st->print("UNEXPECTED TYPE");
1578 type->print();
1579 }
1580 }
1581 }
1582
1583 // ------------------------------------------------------------------
1584 // ciTypeFlow::StateVector::print_on
1585 void ciTypeFlow::StateVector::print_on(outputStream* st) const {
1586 int num_locals = _outer->max_locals();
1587 int num_stack = stack_size();
1588 int num_monitors = monitor_count();
1589 st->print_cr(" State : locals %d, stack %d, monitors %d", num_locals, num_stack, num_monitors);
1590 if (num_stack >= 0) {
1591 int i;
1592 for (i = 0; i < num_locals; i++) {
1593 st->print(" local %2d : ", i);
1594 print_cell_on(st, local(i));
1595 st->cr();
1596 }
1597 for (i = 0; i < num_stack; i++) {
1598 st->print(" stack %2d : ", i);
1599 print_cell_on(st, stack(i));
1600 st->cr();
1601 }
1602 }
1603 }
1604 #endif
1605
1606
1607 // ------------------------------------------------------------------
1608 // ciTypeFlow::SuccIter::next
1609 //
1610 void ciTypeFlow::SuccIter::next() {
1611 int succ_ct = _pred->successors()->length();
1612 int next = _index + 1;
1613 if (next < succ_ct) {
1614 _index = next;
1615 _succ = _pred->successors()->at(next);
1616 return;
1617 }
1618 for (int i = next - succ_ct; i < _pred->exceptions()->length(); i++) {
1619 // Do not compile any code for unloaded exception types.
1620 // Following compiler passes are responsible for doing this also.
1621 ciInstanceKlass* exception_klass = _pred->exc_klasses()->at(i);
1622 if (exception_klass->is_loaded()) {
1623 _index = next;
1624 _succ = _pred->exceptions()->at(i);
1625 return;
1626 }
1627 next++;
1628 }
1629 _index = -1;
1630 _succ = nullptr;
1631 }
1632
1633 // ------------------------------------------------------------------
1634 // ciTypeFlow::SuccIter::set_succ
1635 //
1636 void ciTypeFlow::SuccIter::set_succ(Block* succ) {
1637 int succ_ct = _pred->successors()->length();
1638 if (_index < succ_ct) {
1639 _pred->successors()->at_put(_index, succ);
1640 } else {
1641 int idx = _index - succ_ct;
1642 _pred->exceptions()->at_put(idx, succ);
1643 }
1644 }
1645
1646 // ciTypeFlow::Block
1647 //
1648 // A basic block.
1649
1650 // ------------------------------------------------------------------
1651 // ciTypeFlow::Block::Block
1652 ciTypeFlow::Block::Block(ciTypeFlow* outer,
1653 ciBlock *ciblk,
1654 ciTypeFlow::JsrSet* jsrs) : _predecessors(outer->arena(), 1, 0, nullptr) {
1655 _ciblock = ciblk;
1656 _exceptions = nullptr;
1657 _exc_klasses = nullptr;
1658 _successors = nullptr;
1659 _state = new (outer->arena()) StateVector(outer);
1660 JsrSet* new_jsrs =
1661 new (outer->arena()) JsrSet(outer->arena(), jsrs->size());
1662 jsrs->copy_into(new_jsrs);
1663 _jsrs = new_jsrs;
1664 _next = nullptr;
1665 _on_work_list = false;
1666 _backedge_copy = false;
1667 _has_monitorenter = false;
1668 _trap_bci = -1;
1669 _trap_index = 0;
1670 df_init();
1671
1672 if (CITraceTypeFlow) {
1673 tty->print_cr(">> Created new block");
1674 print_on(tty);
1675 }
1676
1677 assert(this->outer() == outer, "outer link set up");
1678 assert(!outer->have_block_count(), "must not have mapped blocks yet");
1679 }
1680
1681 // ------------------------------------------------------------------
1682 // ciTypeFlow::Block::df_init
1683 void ciTypeFlow::Block::df_init() {
1684 _pre_order = -1; assert(!has_pre_order(), "");
1685 _post_order = -1; assert(!has_post_order(), "");
1686 _loop = nullptr;
1687 _irreducible_loop_head = false;
1688 _irreducible_loop_secondary_entry = false;
1689 _rpo_next = nullptr;
1690 }
1691
1692 // ------------------------------------------------------------------
1693 // ciTypeFlow::Block::successors
1694 //
1695 // Get the successors for this Block.
1696 GrowableArray<ciTypeFlow::Block*>*
1697 ciTypeFlow::Block::successors(ciBytecodeStream* str,
1698 ciTypeFlow::StateVector* state,
1699 ciTypeFlow::JsrSet* jsrs) {
1700 if (_successors == nullptr) {
1701 if (CITraceTypeFlow) {
1702 tty->print(">> Computing successors for block ");
1703 print_value_on(tty);
1704 tty->cr();
1705 }
1706
1707 ciTypeFlow* analyzer = outer();
1708 Arena* arena = analyzer->arena();
1709 Block* block = nullptr;
1710 bool has_successor = !has_trap() &&
1711 (control() != ciBlock::fall_through_bci || limit() < analyzer->code_size());
1712 if (!has_successor) {
1713 _successors =
1714 new (arena) GrowableArray<Block*>(arena, 1, 0, nullptr);
1715 // No successors
1716 } else if (control() == ciBlock::fall_through_bci) {
1717 assert(str->cur_bci() == limit(), "bad block end");
1718 // This block simply falls through to the next.
1719 _successors =
1720 new (arena) GrowableArray<Block*>(arena, 1, 0, nullptr);
1721
1722 Block* block = analyzer->block_at(limit(), _jsrs);
1723 assert(_successors->length() == FALL_THROUGH, "");
1724 _successors->append(block);
1725 } else {
1726 int current_bci = str->cur_bci();
1727 int next_bci = str->next_bci();
1728 int branch_bci = -1;
1729 Block* target = nullptr;
1730 assert(str->next_bci() == limit(), "bad block end");
1731 // This block is not a simple fall-though. Interpret
1732 // the current bytecode to find our successors.
1733 switch (str->cur_bc()) {
1734 case Bytecodes::_ifeq: case Bytecodes::_ifne:
1735 case Bytecodes::_iflt: case Bytecodes::_ifge:
1736 case Bytecodes::_ifgt: case Bytecodes::_ifle:
1737 case Bytecodes::_if_icmpeq: case Bytecodes::_if_icmpne:
1738 case Bytecodes::_if_icmplt: case Bytecodes::_if_icmpge:
1739 case Bytecodes::_if_icmpgt: case Bytecodes::_if_icmple:
1740 case Bytecodes::_if_acmpeq: case Bytecodes::_if_acmpne:
1741 case Bytecodes::_ifnull: case Bytecodes::_ifnonnull:
1742 // Our successors are the branch target and the next bci.
1743 branch_bci = str->get_dest();
1744 _successors =
1745 new (arena) GrowableArray<Block*>(arena, 2, 0, nullptr);
1746 assert(_successors->length() == IF_NOT_TAKEN, "");
1747 _successors->append(analyzer->block_at(next_bci, jsrs));
1748 assert(_successors->length() == IF_TAKEN, "");
1749 _successors->append(analyzer->block_at(branch_bci, jsrs));
1750 break;
1751
1752 case Bytecodes::_goto:
1753 branch_bci = str->get_dest();
1754 _successors =
1755 new (arena) GrowableArray<Block*>(arena, 1, 0, nullptr);
1756 assert(_successors->length() == GOTO_TARGET, "");
1757 _successors->append(analyzer->block_at(branch_bci, jsrs));
1758 break;
1759
1760 case Bytecodes::_jsr:
1761 branch_bci = str->get_dest();
1762 _successors =
1763 new (arena) GrowableArray<Block*>(arena, 1, 0, nullptr);
1764 assert(_successors->length() == GOTO_TARGET, "");
1765 _successors->append(analyzer->block_at(branch_bci, jsrs));
1766 break;
1767
1768 case Bytecodes::_goto_w:
1769 case Bytecodes::_jsr_w:
1770 _successors =
1771 new (arena) GrowableArray<Block*>(arena, 1, 0, nullptr);
1772 assert(_successors->length() == GOTO_TARGET, "");
1773 _successors->append(analyzer->block_at(str->get_far_dest(), jsrs));
1774 break;
1775
1776 case Bytecodes::_tableswitch: {
1777 Bytecode_tableswitch tableswitch(str);
1778
1779 int len = tableswitch.length();
1780 _successors =
1781 new (arena) GrowableArray<Block*>(arena, len+1, 0, nullptr);
1782 int bci = current_bci + tableswitch.default_offset();
1783 Block* block = analyzer->block_at(bci, jsrs);
1784 assert(_successors->length() == SWITCH_DEFAULT, "");
1785 _successors->append(block);
1786 while (--len >= 0) {
1787 int bci = current_bci + tableswitch.dest_offset_at(len);
1788 block = analyzer->block_at(bci, jsrs);
1789 assert(_successors->length() >= SWITCH_CASES, "");
1790 _successors->append_if_missing(block);
1791 }
1792 break;
1793 }
1794
1795 case Bytecodes::_lookupswitch: {
1796 Bytecode_lookupswitch lookupswitch(str);
1797
1798 int npairs = lookupswitch.number_of_pairs();
1799 _successors =
1800 new (arena) GrowableArray<Block*>(arena, npairs+1, 0, nullptr);
1801 int bci = current_bci + lookupswitch.default_offset();
1802 Block* block = analyzer->block_at(bci, jsrs);
1803 assert(_successors->length() == SWITCH_DEFAULT, "");
1804 _successors->append(block);
1805 while(--npairs >= 0) {
1806 LookupswitchPair pair = lookupswitch.pair_at(npairs);
1807 int bci = current_bci + pair.offset();
1808 Block* block = analyzer->block_at(bci, jsrs);
1809 assert(_successors->length() >= SWITCH_CASES, "");
1810 _successors->append_if_missing(block);
1811 }
1812 break;
1813 }
1814
1815 case Bytecodes::_athrow:
1816 case Bytecodes::_ireturn:
1817 case Bytecodes::_lreturn:
1818 case Bytecodes::_freturn:
1819 case Bytecodes::_dreturn:
1820 case Bytecodes::_areturn:
1821 case Bytecodes::_return:
1822 _successors =
1823 new (arena) GrowableArray<Block*>(arena, 1, 0, nullptr);
1824 // No successors
1825 break;
1826
1827 case Bytecodes::_ret: {
1828 _successors =
1829 new (arena) GrowableArray<Block*>(arena, 1, 0, nullptr);
1830
1831 Cell local = state->local(str->get_index());
1832 ciType* return_address = state->type_at(local);
1833 assert(return_address->is_return_address(), "verify: wrong type");
1834 int bci = return_address->as_return_address()->bci();
1835 assert(_successors->length() == GOTO_TARGET, "");
1836 _successors->append(analyzer->block_at(bci, jsrs));
1837 break;
1838 }
1839
1840 case Bytecodes::_wide:
1841 default:
1842 ShouldNotReachHere();
1843 break;
1844 }
1845 }
1846
1847 // Set predecessor information
1848 for (int i = 0; i < _successors->length(); i++) {
1849 Block* block = _successors->at(i);
1850 block->predecessors()->append(this);
1851 }
1852 }
1853 return _successors;
1854 }
1855
1856 // ------------------------------------------------------------------
1857 // ciTypeFlow::Block:compute_exceptions
1858 //
1859 // Compute the exceptional successors and types for this Block.
1860 void ciTypeFlow::Block::compute_exceptions() {
1861 assert(_exceptions == nullptr && _exc_klasses == nullptr, "repeat");
1862
1863 if (CITraceTypeFlow) {
1864 tty->print(">> Computing exceptions for block ");
1865 print_value_on(tty);
1866 tty->cr();
1867 }
1868
1869 ciTypeFlow* analyzer = outer();
1870 Arena* arena = analyzer->arena();
1871
1872 // Any bci in the block will do.
1873 ciExceptionHandlerStream str(analyzer->method(), start());
1874
1875 // Allocate our growable arrays.
1876 int exc_count = str.count();
1877 _exceptions = new (arena) GrowableArray<Block*>(arena, exc_count, 0, nullptr);
1878 _exc_klasses = new (arena) GrowableArray<ciInstanceKlass*>(arena, exc_count,
1879 0, nullptr);
1880
1881 for ( ; !str.is_done(); str.next()) {
1882 ciExceptionHandler* handler = str.handler();
1883 int bci = handler->handler_bci();
1884 ciInstanceKlass* klass = nullptr;
1885 if (bci == -1) {
1886 // There is no catch all. It is possible to exit the method.
1887 break;
1888 }
1889 if (handler->is_catch_all()) {
1890 klass = analyzer->env()->Throwable_klass();
1891 } else {
1892 klass = handler->catch_klass();
1893 }
1894 Block* block = analyzer->block_at(bci, _jsrs);
1895 _exceptions->append(block);
1896 block->predecessors()->append(this);
1897 _exc_klasses->append(klass);
1898 }
1899 }
1900
1901 // ------------------------------------------------------------------
1902 // ciTypeFlow::Block::set_backedge_copy
1903 // Use this only to make a pre-existing public block into a backedge copy.
1904 void ciTypeFlow::Block::set_backedge_copy(bool z) {
1905 assert(z || (z == is_backedge_copy()), "cannot make a backedge copy public");
1906 _backedge_copy = z;
1907 }
1908
1909 // Analogous to PhaseIdealLoop::is_in_irreducible_loop
1910 bool ciTypeFlow::Block::is_in_irreducible_loop() const {
1911 if (!outer()->has_irreducible_entry()) {
1912 return false; // No irreducible loop in method.
1913 }
1914 Loop* lp = loop(); // Innermost loop containing block.
1915 if (lp == nullptr) {
1916 assert(!is_post_visited(), "must have enclosing loop once post-visited");
1917 return false; // Not yet processed, so we do not know, yet.
1918 }
1919 // Walk all the way up the loop-tree, search for an irreducible loop.
1920 do {
1921 if (lp->is_irreducible()) {
1922 return true; // We are in irreducible loop.
1923 }
1924 if (lp->head()->pre_order() == 0) {
1925 return false; // Found root loop, terminate.
1926 }
1927 lp = lp->parent();
1928 } while (lp != nullptr);
1929 // We have "lp->parent() == nullptr", which happens only for infinite loops,
1930 // where no parent is attached to the loop. We did not find any irreducible
1931 // loop from this block out to lp. Thus lp only has one entry, and no exit
1932 // (it is infinite and reducible). We can always rewrite an infinite loop
1933 // that is nested inside other loops:
1934 // while(condition) { infinite_loop; }
1935 // with an equivalent program where the infinite loop is an outermost loop
1936 // that is not nested in any loop:
1937 // while(condition) { break; } infinite_loop;
1938 // Thus, we can understand lp as an outermost loop, and can terminate and
1939 // conclude: this block is in no irreducible loop.
1940 return false;
1941 }
1942
1943 // ------------------------------------------------------------------
1944 // ciTypeFlow::Block::is_clonable_exit
1945 //
1946 // At most 2 normal successors, one of which continues looping,
1947 // and all exceptional successors must exit.
1948 bool ciTypeFlow::Block::is_clonable_exit(ciTypeFlow::Loop* lp) {
1949 int normal_cnt = 0;
1950 int in_loop_cnt = 0;
1951 for (SuccIter iter(this); !iter.done(); iter.next()) {
1952 Block* succ = iter.succ();
1953 if (iter.is_normal_ctrl()) {
1954 if (++normal_cnt > 2) return false;
1955 if (lp->contains(succ->loop())) {
1956 if (++in_loop_cnt > 1) return false;
1957 }
1958 } else {
1959 if (lp->contains(succ->loop())) return false;
1960 }
1961 }
1962 return in_loop_cnt == 1;
1963 }
1964
1965 // ------------------------------------------------------------------
1966 // ciTypeFlow::Block::looping_succ
1967 //
1968 ciTypeFlow::Block* ciTypeFlow::Block::looping_succ(ciTypeFlow::Loop* lp) {
1969 assert(successors()->length() <= 2, "at most 2 normal successors");
1970 for (SuccIter iter(this); !iter.done(); iter.next()) {
1971 Block* succ = iter.succ();
1972 if (lp->contains(succ->loop())) {
1973 return succ;
1974 }
1975 }
1976 return nullptr;
1977 }
1978
1979 #ifndef PRODUCT
1980 // ------------------------------------------------------------------
1981 // ciTypeFlow::Block::print_value_on
1982 void ciTypeFlow::Block::print_value_on(outputStream* st) const {
1983 if (has_pre_order()) st->print("#%-2d ", pre_order());
1984 if (has_rpo()) st->print("rpo#%-2d ", rpo());
1985 st->print("[%d - %d)", start(), limit());
1986 if (is_loop_head()) st->print(" lphd");
1987 if (is_in_irreducible_loop()) st->print(" in_irred");
1988 if (is_irreducible_loop_head()) st->print(" irred_head");
1989 if (is_irreducible_loop_secondary_entry()) st->print(" irred_entry");
1990 if (_jsrs->size() > 0) { st->print("/"); _jsrs->print_on(st); }
1991 if (is_backedge_copy()) st->print("/backedge_copy");
1992 }
1993
1994 // ------------------------------------------------------------------
1995 // ciTypeFlow::Block::print_on
1996 void ciTypeFlow::Block::print_on(outputStream* st) const {
1997 if ((Verbose || WizardMode) && (limit() >= 0)) {
1998 // Don't print 'dummy' blocks (i.e. blocks with limit() '-1')
1999 outer()->method()->print_codes_on(start(), limit(), st);
2000 }
2001 st->print_cr(" ==================================================== ");
2002 st->print (" ");
2003 print_value_on(st);
2004 st->print(" Stored locals: "); def_locals()->print_on(st, outer()->method()->max_locals()); tty->cr();
2005 if (loop() && loop()->parent() != nullptr) {
2006 st->print(" loops:");
2007 Loop* lp = loop();
2008 do {
2009 st->print(" %d<-%d", lp->head()->pre_order(),lp->tail()->pre_order());
2010 if (lp->is_irreducible()) st->print("(ir)");
2011 lp = lp->parent();
2012 } while (lp->parent() != nullptr);
2013 }
2014 st->cr();
2015 _state->print_on(st);
2016 if (_successors == nullptr) {
2017 st->print_cr(" No successor information");
2018 } else {
2019 int num_successors = _successors->length();
2020 st->print_cr(" Successors : %d", num_successors);
2021 for (int i = 0; i < num_successors; i++) {
2022 Block* successor = _successors->at(i);
2023 st->print(" ");
2024 successor->print_value_on(st);
2025 st->cr();
2026 }
2027 }
2028 if (_predecessors.is_empty()) {
2029 st->print_cr(" No predecessor information");
2030 } else {
2031 int num_predecessors = _predecessors.length();
2032 st->print_cr(" Predecessors : %d", num_predecessors);
2033 for (int i = 0; i < num_predecessors; i++) {
2034 Block* predecessor = _predecessors.at(i);
2035 st->print(" ");
2036 predecessor->print_value_on(st);
2037 st->cr();
2038 }
2039 }
2040 if (_exceptions == nullptr) {
2041 st->print_cr(" No exception information");
2042 } else {
2043 int num_exceptions = _exceptions->length();
2044 st->print_cr(" Exceptions : %d", num_exceptions);
2045 for (int i = 0; i < num_exceptions; i++) {
2046 Block* exc_succ = _exceptions->at(i);
2047 ciInstanceKlass* exc_klass = _exc_klasses->at(i);
2048 st->print(" ");
2049 exc_succ->print_value_on(st);
2050 st->print(" -- ");
2051 exc_klass->name()->print_symbol_on(st);
2052 st->cr();
2053 }
2054 }
2055 if (has_trap()) {
2056 st->print_cr(" Traps on %d with trap index %d", trap_bci(), trap_index());
2057 }
2058 st->print_cr(" ==================================================== ");
2059 }
2060 #endif
2061
2062 #ifndef PRODUCT
2063 // ------------------------------------------------------------------
2064 // ciTypeFlow::LocalSet::print_on
2065 void ciTypeFlow::LocalSet::print_on(outputStream* st, int limit) const {
2066 st->print("{");
2067 for (int i = 0; i < max; i++) {
2068 if (test(i)) st->print(" %d", i);
2069 }
2070 if (limit > max) {
2071 st->print(" %d..%d ", max, limit);
2072 }
2073 st->print(" }");
2074 }
2075 #endif
2076
2077 // ciTypeFlow
2078 //
2079 // This is a pass over the bytecodes which computes the following:
2080 // basic block structure
2081 // interpreter type-states (a la the verifier)
2082
2083 // ------------------------------------------------------------------
2084 // ciTypeFlow::ciTypeFlow
2085 ciTypeFlow::ciTypeFlow(ciEnv* env, ciMethod* method, int osr_bci) {
2086 _env = env;
2087 _method = method;
2088 _has_irreducible_entry = false;
2089 _osr_bci = osr_bci;
2090 _failure_reason = nullptr;
2091 assert(0 <= start_bci() && start_bci() < code_size() , "correct osr_bci argument: 0 <= %d < %d", start_bci(), code_size());
2092 _work_list = nullptr;
2093
2094 int ciblock_count = _method->get_method_blocks()->num_blocks();
2095 _idx_to_blocklist = NEW_ARENA_ARRAY(arena(), GrowableArray<Block*>*, ciblock_count);
2096 for (int i = 0; i < ciblock_count; i++) {
2097 _idx_to_blocklist[i] = nullptr;
2098 }
2099 _block_map = nullptr; // until all blocks are seen
2100 _jsr_records = nullptr;
2101 }
2102
2103 // ------------------------------------------------------------------
2104 // ciTypeFlow::work_list_next
2105 //
2106 // Get the next basic block from our work list.
2107 ciTypeFlow::Block* ciTypeFlow::work_list_next() {
2108 assert(!work_list_empty(), "work list must not be empty");
2109 Block* next_block = _work_list;
2110 _work_list = next_block->next();
2111 next_block->set_next(nullptr);
2112 next_block->set_on_work_list(false);
2113 return next_block;
2114 }
2115
2116 // ------------------------------------------------------------------
2117 // ciTypeFlow::add_to_work_list
2118 //
2119 // Add a basic block to our work list.
2120 // List is sorted by decreasing postorder sort (same as increasing RPO)
2121 void ciTypeFlow::add_to_work_list(ciTypeFlow::Block* block) {
2122 assert(!block->is_on_work_list(), "must not already be on work list");
2123
2124 if (CITraceTypeFlow) {
2125 tty->print(">> Adding block ");
2126 block->print_value_on(tty);
2127 tty->print_cr(" to the work list : ");
2128 }
2129
2130 block->set_on_work_list(true);
2131
2132 // decreasing post order sort
2133
2134 Block* prev = nullptr;
2135 Block* current = _work_list;
2136 int po = block->post_order();
2137 while (current != nullptr) {
2138 if (!current->has_post_order() || po > current->post_order())
2139 break;
2140 prev = current;
2141 current = current->next();
2142 }
2143 if (prev == nullptr) {
2144 block->set_next(_work_list);
2145 _work_list = block;
2146 } else {
2147 block->set_next(current);
2148 prev->set_next(block);
2149 }
2150
2151 if (CITraceTypeFlow) {
2152 tty->cr();
2153 }
2154 }
2155
2156 // ------------------------------------------------------------------
2157 // ciTypeFlow::block_at
2158 //
2159 // Return the block beginning at bci which has a JsrSet compatible
2160 // with jsrs.
2161 ciTypeFlow::Block* ciTypeFlow::block_at(int bci, ciTypeFlow::JsrSet* jsrs, CreateOption option) {
2162 // First find the right ciBlock.
2163 if (CITraceTypeFlow) {
2164 tty->print(">> Requesting block for %d/", bci);
2165 jsrs->print_on(tty);
2166 tty->cr();
2167 }
2168
2169 ciBlock* ciblk = _method->get_method_blocks()->block_containing(bci);
2170 assert(ciblk->start_bci() == bci, "bad ciBlock boundaries");
2171 Block* block = get_block_for(ciblk->index(), jsrs, option);
2172
2173 assert(block == nullptr? (option == no_create): block->is_backedge_copy() == (option == create_backedge_copy), "create option consistent with result");
2174
2175 if (CITraceTypeFlow) {
2176 if (block != nullptr) {
2177 tty->print(">> Found block ");
2178 block->print_value_on(tty);
2179 tty->cr();
2180 } else {
2181 tty->print_cr(">> No such block.");
2182 }
2183 }
2184
2185 return block;
2186 }
2187
2188 // ------------------------------------------------------------------
2189 // ciTypeFlow::make_jsr_record
2190 //
2191 // Make a JsrRecord for a given (entry, return) pair, if such a record
2192 // does not already exist.
2193 ciTypeFlow::JsrRecord* ciTypeFlow::make_jsr_record(int entry_address,
2194 int return_address) {
2195 if (_jsr_records == nullptr) {
2196 _jsr_records = new (arena()) GrowableArray<JsrRecord*>(arena(),
2197 2,
2198 0,
2199 nullptr);
2200 }
2201 JsrRecord* record = nullptr;
2202 int len = _jsr_records->length();
2203 for (int i = 0; i < len; i++) {
2204 JsrRecord* record = _jsr_records->at(i);
2205 if (record->entry_address() == entry_address &&
2206 record->return_address() == return_address) {
2207 return record;
2208 }
2209 }
2210
2211 record = new (arena()) JsrRecord(entry_address, return_address);
2212 _jsr_records->append(record);
2213 return record;
2214 }
2215
2216 // ------------------------------------------------------------------
2217 // ciTypeFlow::flow_exceptions
2218 //
2219 // Merge the current state into all exceptional successors at the
2220 // current point in the code.
2221 void ciTypeFlow::flow_exceptions(GrowableArray<ciTypeFlow::Block*>* exceptions,
2222 GrowableArray<ciInstanceKlass*>* exc_klasses,
2223 ciTypeFlow::StateVector* state) {
2224 int len = exceptions->length();
2225 assert(exc_klasses->length() == len, "must have same length");
2226 for (int i = 0; i < len; i++) {
2227 Block* block = exceptions->at(i);
2228 ciInstanceKlass* exception_klass = exc_klasses->at(i);
2229
2230 if (!exception_klass->is_loaded()) {
2231 // Do not compile any code for unloaded exception types.
2232 // Following compiler passes are responsible for doing this also.
2233 continue;
2234 }
2235
2236 if (block->meet_exception(exception_klass, state)) {
2237 // Block was modified and has PO. Add it to the work list.
2238 if (block->has_post_order() &&
2239 !block->is_on_work_list()) {
2240 add_to_work_list(block);
2241 }
2242 }
2243 }
2244 }
2245
2246 // ------------------------------------------------------------------
2247 // ciTypeFlow::flow_successors
2248 //
2249 // Merge the current state into all successors at the current point
2250 // in the code.
2251 void ciTypeFlow::flow_successors(GrowableArray<ciTypeFlow::Block*>* successors,
2252 ciTypeFlow::StateVector* state) {
2253 int len = successors->length();
2254 for (int i = 0; i < len; i++) {
2255 Block* block = successors->at(i);
2256 if (block->meet(state)) {
2257 // Block was modified and has PO. Add it to the work list.
2258 if (block->has_post_order() &&
2259 !block->is_on_work_list()) {
2260 add_to_work_list(block);
2261 }
2262 }
2263 }
2264 }
2265
2266 // ------------------------------------------------------------------
2267 // ciTypeFlow::can_trap
2268 //
2269 // Tells if a given instruction is able to generate an exception edge.
2270 bool ciTypeFlow::can_trap(ciBytecodeStream& str) {
2271 // Cf. GenerateOopMap::do_exception_edge.
2272 if (!Bytecodes::can_trap(str.cur_bc())) return false;
2273
2274 switch (str.cur_bc()) {
2275 case Bytecodes::_ldc:
2276 case Bytecodes::_ldc_w:
2277 case Bytecodes::_ldc2_w:
2278 return str.is_in_error() || !str.get_constant().is_loaded();
2279
2280 case Bytecodes::_aload_0:
2281 // These bytecodes can trap for rewriting. We need to assume that
2282 // they do not throw exceptions to make the monitor analysis work.
2283 return false;
2284
2285 case Bytecodes::_ireturn:
2286 case Bytecodes::_lreturn:
2287 case Bytecodes::_freturn:
2288 case Bytecodes::_dreturn:
2289 case Bytecodes::_areturn:
2290 case Bytecodes::_return:
2291 // We can assume the monitor stack is empty in this analysis.
2292 return false;
2293
2294 case Bytecodes::_monitorexit:
2295 // We can assume monitors are matched in this analysis.
2296 return false;
2297
2298 default:
2299 return true;
2300 }
2301 }
2302
2303 // ------------------------------------------------------------------
2304 // ciTypeFlow::clone_loop_heads
2305 //
2306 // Clone the loop heads
2307 bool ciTypeFlow::clone_loop_heads(StateVector* temp_vector, JsrSet* temp_set) {
2308 bool rslt = false;
2309 for (PreorderLoops iter(loop_tree_root()); !iter.done(); iter.next()) {
2310 Loop* lp = iter.current();
2311 Block* head = lp->head();
2312 if (lp == loop_tree_root() ||
2313 lp->is_irreducible() ||
2314 !head->is_clonable_exit(lp))
2315 continue;
2316
2317 // Avoid BoxLock merge.
2318 if (EliminateNestedLocks && head->has_monitorenter())
2319 continue;
2320
2321 // check not already cloned
2322 if (head->backedge_copy_count() != 0)
2323 continue;
2324
2325 // Don't clone head of OSR loop to get correct types in start block.
2326 if (is_osr_flow() && head->start() == start_bci())
2327 continue;
2328
2329 // check _no_ shared head below us
2330 Loop* ch;
2331 for (ch = lp->child(); ch != nullptr && ch->head() != head; ch = ch->sibling());
2332 if (ch != nullptr)
2333 continue;
2334
2335 // Clone head
2336 Block* new_head = head->looping_succ(lp);
2337 Block* clone = clone_loop_head(lp, temp_vector, temp_set);
2338 // Update lp's info
2339 clone->set_loop(lp);
2340 lp->set_head(new_head);
2341 lp->set_tail(clone);
2342 // And move original head into outer loop
2343 head->set_loop(lp->parent());
2344
2345 rslt = true;
2346 }
2347 return rslt;
2348 }
2349
2350 // ------------------------------------------------------------------
2351 // ciTypeFlow::clone_loop_head
2352 //
2353 // Clone lp's head and replace tail's successors with clone.
2354 //
2355 // |
2356 // v
2357 // head <-> body
2358 // |
2359 // v
2360 // exit
2361 //
2362 // new_head
2363 //
2364 // |
2365 // v
2366 // head ----------\
2367 // | |
2368 // | v
2369 // | clone <-> body
2370 // | |
2371 // | /--/
2372 // | |
2373 // v v
2374 // exit
2375 //
2376 ciTypeFlow::Block* ciTypeFlow::clone_loop_head(Loop* lp, StateVector* temp_vector, JsrSet* temp_set) {
2377 Block* head = lp->head();
2378 Block* tail = lp->tail();
2379 if (CITraceTypeFlow) {
2380 tty->print(">> Requesting clone of loop head "); head->print_value_on(tty);
2381 tty->print(" for predecessor "); tail->print_value_on(tty);
2382 tty->cr();
2383 }
2384 Block* clone = block_at(head->start(), head->jsrs(), create_backedge_copy);
2385 assert(clone->backedge_copy_count() == 1, "one backedge copy for all back edges");
2386
2387 assert(!clone->has_pre_order(), "just created");
2388 clone->set_next_pre_order();
2389
2390 // Accumulate profiled count for all backedges that share this loop's head
2391 int total_count = lp->profiled_count();
2392 for (Loop* lp1 = lp->parent(); lp1 != nullptr; lp1 = lp1->parent()) {
2393 for (Loop* lp2 = lp1; lp2 != nullptr; lp2 = lp2->sibling()) {
2394 if (lp2->head() == head && !lp2->tail()->is_backedge_copy()) {
2395 total_count += lp2->profiled_count();
2396 }
2397 }
2398 }
2399 // Have the most frequent ones branch to the clone instead
2400 int count = 0;
2401 int loops_with_shared_head = 0;
2402 Block* latest_tail = tail;
2403 bool done = false;
2404 for (Loop* lp1 = lp; lp1 != nullptr && !done; lp1 = lp1->parent()) {
2405 for (Loop* lp2 = lp1; lp2 != nullptr && !done; lp2 = lp2->sibling()) {
2406 if (lp2->head() == head && !lp2->tail()->is_backedge_copy()) {
2407 count += lp2->profiled_count();
2408 if (lp2->tail()->post_order() < latest_tail->post_order()) {
2409 latest_tail = lp2->tail();
2410 }
2411 loops_with_shared_head++;
2412 for (SuccIter iter(lp2->tail()); !iter.done(); iter.next()) {
2413 if (iter.succ() == head) {
2414 iter.set_succ(clone);
2415 // Update predecessor information
2416 head->predecessors()->remove(lp2->tail());
2417 clone->predecessors()->append(lp2->tail());
2418 }
2419 }
2420 flow_block(lp2->tail(), temp_vector, temp_set);
2421 if (lp2->head() == lp2->tail()) {
2422 // For self-loops, clone->head becomes clone->clone
2423 flow_block(clone, temp_vector, temp_set);
2424 for (SuccIter iter(clone); !iter.done(); iter.next()) {
2425 if (iter.succ() == lp2->head()) {
2426 iter.set_succ(clone);
2427 // Update predecessor information
2428 lp2->head()->predecessors()->remove(clone);
2429 clone->predecessors()->append(clone);
2430 break;
2431 }
2432 }
2433 }
2434 if (total_count == 0 || count > (total_count * .9)) {
2435 done = true;
2436 }
2437 }
2438 }
2439 }
2440 assert(loops_with_shared_head >= 1, "at least one new");
2441 clone->set_rpo_next(latest_tail->rpo_next());
2442 latest_tail->set_rpo_next(clone);
2443 flow_block(clone, temp_vector, temp_set);
2444
2445 return clone;
2446 }
2447
2448 // ------------------------------------------------------------------
2449 // ciTypeFlow::flow_block
2450 //
2451 // Interpret the effects of the bytecodes on the incoming state
2452 // vector of a basic block. Push the changed state to succeeding
2453 // basic blocks.
2454 void ciTypeFlow::flow_block(ciTypeFlow::Block* block,
2455 ciTypeFlow::StateVector* state,
2456 ciTypeFlow::JsrSet* jsrs) {
2457 if (CITraceTypeFlow) {
2458 tty->print("\n>> ANALYZING BLOCK : ");
2459 tty->cr();
2460 block->print_on(tty);
2461 }
2462 assert(block->has_pre_order(), "pre-order is assigned before 1st flow");
2463
2464 int start = block->start();
2465 int limit = block->limit();
2466 int control = block->control();
2467 if (control != ciBlock::fall_through_bci) {
2468 limit = control;
2469 }
2470
2471 // Grab the state from the current block.
2472 block->copy_state_into(state);
2473 state->def_locals()->clear();
2474
2475 GrowableArray<Block*>* exceptions = block->exceptions();
2476 GrowableArray<ciInstanceKlass*>* exc_klasses = block->exc_klasses();
2477 bool has_exceptions = exceptions->length() > 0;
2478
2479 bool exceptions_used = false;
2480
2481 ciBytecodeStream str(method());
2482 str.reset_to_bci(start);
2483 Bytecodes::Code code;
2484 while ((code = str.next()) != ciBytecodeStream::EOBC() &&
2485 str.cur_bci() < limit) {
2486 // Check for exceptional control flow from this point.
2487 if (has_exceptions && can_trap(str)) {
2488 flow_exceptions(exceptions, exc_klasses, state);
2489 exceptions_used = true;
2490 }
2491 // Apply the effects of the current bytecode to our state.
2492 bool res = state->apply_one_bytecode(&str);
2493
2494 // Watch for bailouts.
2495 if (failing()) return;
2496
2497 if (str.cur_bc() == Bytecodes::_monitorenter) {
2498 block->set_has_monitorenter();
2499 }
2500
2501 if (res) {
2502
2503 // We have encountered a trap. Record it in this block.
2504 block->set_trap(state->trap_bci(), state->trap_index());
2505
2506 if (CITraceTypeFlow) {
2507 tty->print_cr(">> Found trap");
2508 block->print_on(tty);
2509 }
2510
2511 // Save set of locals defined in this block
2512 block->def_locals()->add(state->def_locals());
2513
2514 // Record (no) successors.
2515 block->successors(&str, state, jsrs);
2516
2517 assert(!has_exceptions || exceptions_used, "Not removing exceptions");
2518
2519 // Discontinue interpretation of this Block.
2520 return;
2521 }
2522 }
2523
2524 GrowableArray<Block*>* successors = nullptr;
2525 if (control != ciBlock::fall_through_bci) {
2526 // Check for exceptional control flow from this point.
2527 if (has_exceptions && can_trap(str)) {
2528 flow_exceptions(exceptions, exc_klasses, state);
2529 exceptions_used = true;
2530 }
2531
2532 // Fix the JsrSet to reflect effect of the bytecode.
2533 block->copy_jsrs_into(jsrs);
2534 jsrs->apply_control(this, &str, state);
2535
2536 // Find successor edges based on old state and new JsrSet.
2537 successors = block->successors(&str, state, jsrs);
2538
2539 // Apply the control changes to the state.
2540 state->apply_one_bytecode(&str);
2541 } else {
2542 // Fall through control
2543 successors = block->successors(&str, nullptr, nullptr);
2544 }
2545
2546 // Save set of locals defined in this block
2547 block->def_locals()->add(state->def_locals());
2548
2549 // Remove untaken exception paths
2550 if (!exceptions_used)
2551 exceptions->clear();
2552
2553 // Pass our state to successors.
2554 flow_successors(successors, state);
2555 }
2556
2557 // ------------------------------------------------------------------
2558 // ciTypeFlow::PreOrderLoops::next
2559 //
2560 // Advance to next loop tree using a preorder, left-to-right traversal.
2561 void ciTypeFlow::PreorderLoops::next() {
2562 assert(!done(), "must not be done.");
2563 if (_current->child() != nullptr) {
2564 _current = _current->child();
2565 } else if (_current->sibling() != nullptr) {
2566 _current = _current->sibling();
2567 } else {
2568 while (_current != _root && _current->sibling() == nullptr) {
2569 _current = _current->parent();
2570 }
2571 if (_current == _root) {
2572 _current = nullptr;
2573 assert(done(), "must be done.");
2574 } else {
2575 assert(_current->sibling() != nullptr, "must be more to do");
2576 _current = _current->sibling();
2577 }
2578 }
2579 }
2580
2581 // If the tail is a branch to the head, retrieve how many times that path was taken from profiling
2582 int ciTypeFlow::Loop::profiled_count() {
2583 if (_profiled_count >= 0) {
2584 return _profiled_count;
2585 }
2586 ciMethodData* methodData = outer()->method()->method_data();
2587 if (!methodData->is_mature()) {
2588 _profiled_count = 0;
2589 return 0;
2590 }
2591 ciTypeFlow::Block* tail = this->tail();
2592 if (tail->control() == -1 || tail->has_trap()) {
2593 _profiled_count = 0;
2594 return 0;
2595 }
2596
2597 ciProfileData* data = methodData->bci_to_data(tail->control());
2598
2599 if (data == nullptr || !data->is_JumpData()) {
2600 _profiled_count = 0;
2601 return 0;
2602 }
2603
2604 ciBytecodeStream iter(outer()->method());
2605 iter.reset_to_bci(tail->control());
2606
2607 bool is_an_if = false;
2608 bool wide = false;
2609 Bytecodes::Code bc = iter.next();
2610 switch (bc) {
2611 case Bytecodes::_ifeq:
2612 case Bytecodes::_ifne:
2613 case Bytecodes::_iflt:
2614 case Bytecodes::_ifge:
2615 case Bytecodes::_ifgt:
2616 case Bytecodes::_ifle:
2617 case Bytecodes::_if_icmpeq:
2618 case Bytecodes::_if_icmpne:
2619 case Bytecodes::_if_icmplt:
2620 case Bytecodes::_if_icmpge:
2621 case Bytecodes::_if_icmpgt:
2622 case Bytecodes::_if_icmple:
2623 case Bytecodes::_if_acmpeq:
2624 case Bytecodes::_if_acmpne:
2625 case Bytecodes::_ifnull:
2626 case Bytecodes::_ifnonnull:
2627 is_an_if = true;
2628 break;
2629 case Bytecodes::_goto_w:
2630 case Bytecodes::_jsr_w:
2631 wide = true;
2632 break;
2633 case Bytecodes::_goto:
2634 case Bytecodes::_jsr:
2635 break;
2636 default:
2637 fatal(" invalid bytecode: %s", Bytecodes::name(iter.cur_bc()));
2638 }
2639
2640 GrowableArray<ciTypeFlow::Block*>* succs = tail->successors();
2641
2642 if (!is_an_if) {
2643 assert(((wide ? iter.get_far_dest() : iter.get_dest()) == head()->start()) == (succs->at(ciTypeFlow::GOTO_TARGET) == head()), "branch should lead to loop head");
2644 if (succs->at(ciTypeFlow::GOTO_TARGET) == head()) {
2645 _profiled_count = outer()->method()->scale_count(data->as_JumpData()->taken());
2646 return _profiled_count;
2647 }
2648 } else {
2649 assert((iter.get_dest() == head()->start()) == (succs->at(ciTypeFlow::IF_TAKEN) == head()), "bytecode and CFG not consistent");
2650 assert((tail->limit() == head()->start()) == (succs->at(ciTypeFlow::IF_NOT_TAKEN) == head()), "bytecode and CFG not consistent");
2651 if (succs->at(ciTypeFlow::IF_TAKEN) == head()) {
2652 _profiled_count = outer()->method()->scale_count(data->as_JumpData()->taken());
2653 return _profiled_count;
2654 } else if (succs->at(ciTypeFlow::IF_NOT_TAKEN) == head()) {
2655 _profiled_count = outer()->method()->scale_count(data->as_BranchData()->not_taken());
2656 return _profiled_count;
2657 }
2658 }
2659
2660 _profiled_count = 0;
2661 return _profiled_count;
2662 }
2663
2664 bool ciTypeFlow::Loop::at_insertion_point(Loop* lp, Loop* current) {
2665 int lp_pre_order = lp->head()->pre_order();
2666 if (current->head()->pre_order() < lp_pre_order) {
2667 return true;
2668 } else if (current->head()->pre_order() > lp_pre_order) {
2669 return false;
2670 }
2671 // In the case of a shared head, make the most frequent head/tail (as reported by profiling) the inner loop
2672 if (current->head() == lp->head()) {
2673 int lp_count = lp->profiled_count();
2674 int current_count = current->profiled_count();
2675 if (current_count < lp_count) {
2676 return true;
2677 } else if (current_count > lp_count) {
2678 return false;
2679 }
2680 }
2681 if (current->tail()->pre_order() > lp->tail()->pre_order()) {
2682 return true;
2683 }
2684 return false;
2685 }
2686
2687 // ------------------------------------------------------------------
2688 // ciTypeFlow::Loop::sorted_merge
2689 //
2690 // Merge the branch lp into this branch, sorting on the loop head
2691 // pre_orders. Returns the leaf of the merged branch.
2692 // Child and sibling pointers will be setup later.
2693 // Sort is (looking from leaf towards the root)
2694 // descending on primary key: loop head's pre_order, and
2695 // ascending on secondary key: loop tail's pre_order.
2696 ciTypeFlow::Loop* ciTypeFlow::Loop::sorted_merge(Loop* lp) {
2697 Loop* leaf = this;
2698 Loop* prev = nullptr;
2699 Loop* current = leaf;
2700 while (lp != nullptr) {
2701 int lp_pre_order = lp->head()->pre_order();
2702 // Find insertion point for "lp"
2703 while (current != nullptr) {
2704 if (current == lp) {
2705 return leaf; // Already in list
2706 }
2707 if (at_insertion_point(lp, current)) {
2708 break;
2709 }
2710 prev = current;
2711 current = current->parent();
2712 }
2713 Loop* next_lp = lp->parent(); // Save future list of items to insert
2714 // Insert lp before current
2715 lp->set_parent(current);
2716 if (prev != nullptr) {
2717 prev->set_parent(lp);
2718 } else {
2719 leaf = lp;
2720 }
2721 prev = lp; // Inserted item is new prev[ious]
2722 lp = next_lp; // Next item to insert
2723 }
2724 return leaf;
2725 }
2726
2727 // ------------------------------------------------------------------
2728 // ciTypeFlow::build_loop_tree
2729 //
2730 // Incrementally build loop tree.
2731 void ciTypeFlow::build_loop_tree(Block* blk) {
2732 assert(!blk->is_post_visited(), "precondition");
2733 Loop* innermost = nullptr; // merge of loop tree branches over all successors
2734
2735 for (SuccIter iter(blk); !iter.done(); iter.next()) {
2736 Loop* lp = nullptr;
2737 Block* succ = iter.succ();
2738 if (!succ->is_post_visited()) {
2739 // Found backedge since predecessor post visited, but successor is not
2740 assert(succ->pre_order() <= blk->pre_order(), "should be backedge");
2741
2742 // Create a LoopNode to mark this loop.
2743 lp = new (arena()) Loop(succ, blk);
2744 if (succ->loop() == nullptr)
2745 succ->set_loop(lp);
2746 // succ->loop will be updated to innermost loop on a later call, when blk==succ
2747
2748 } else { // Nested loop
2749 lp = succ->loop();
2750
2751 // If succ is loop head, find outer loop.
2752 while (lp != nullptr && lp->head() == succ) {
2753 lp = lp->parent();
2754 }
2755 if (lp == nullptr) {
2756 // Infinite loop, it's parent is the root
2757 lp = loop_tree_root();
2758 }
2759 }
2760
2761 // Check for irreducible loop.
2762 // Successor has already been visited. If the successor's loop head
2763 // has already been post-visited, then this is another entry into the loop.
2764 while (lp->head()->is_post_visited() && lp != loop_tree_root()) {
2765 _has_irreducible_entry = true;
2766 lp->set_irreducible(succ);
2767 if (!succ->is_on_work_list()) {
2768 // Assume irreducible entries need more data flow
2769 add_to_work_list(succ);
2770 }
2771 Loop* plp = lp->parent();
2772 if (plp == nullptr) {
2773 // This only happens for some irreducible cases. The parent
2774 // will be updated during a later pass.
2775 break;
2776 }
2777 lp = plp;
2778 }
2779
2780 // Merge loop tree branch for all successors.
2781 innermost = innermost == nullptr ? lp : innermost->sorted_merge(lp);
2782
2783 } // end loop
2784
2785 if (innermost == nullptr) {
2786 assert(blk->successors()->length() == 0, "CFG exit");
2787 blk->set_loop(loop_tree_root());
2788 } else if (innermost->head() == blk) {
2789 // If loop header, complete the tree pointers
2790 if (blk->loop() != innermost) {
2791 #ifdef ASSERT
2792 assert(blk->loop()->head() == innermost->head(), "same head");
2793 Loop* dl;
2794 for (dl = innermost; dl != nullptr && dl != blk->loop(); dl = dl->parent());
2795 assert(dl == blk->loop(), "blk->loop() already in innermost list");
2796 #endif
2797 blk->set_loop(innermost);
2798 }
2799 innermost->def_locals()->add(blk->def_locals());
2800 Loop* l = innermost;
2801 Loop* p = l->parent();
2802 while (p && l->head() == blk) {
2803 l->set_sibling(p->child()); // Put self on parents 'next child'
2804 p->set_child(l); // Make self the first child of parent
2805 p->def_locals()->add(l->def_locals());
2806 l = p; // Walk up the parent chain
2807 p = l->parent();
2808 }
2809 } else {
2810 blk->set_loop(innermost);
2811 innermost->def_locals()->add(blk->def_locals());
2812 }
2813 }
2814
2815 // ------------------------------------------------------------------
2816 // ciTypeFlow::Loop::contains
2817 //
2818 // Returns true if lp is nested loop.
2819 bool ciTypeFlow::Loop::contains(ciTypeFlow::Loop* lp) const {
2820 assert(lp != nullptr, "");
2821 if (this == lp || head() == lp->head()) return true;
2822 int depth1 = depth();
2823 int depth2 = lp->depth();
2824 if (depth1 > depth2)
2825 return false;
2826 while (depth1 < depth2) {
2827 depth2--;
2828 lp = lp->parent();
2829 }
2830 return this == lp;
2831 }
2832
2833 // ------------------------------------------------------------------
2834 // ciTypeFlow::Loop::depth
2835 //
2836 // Loop depth
2837 int ciTypeFlow::Loop::depth() const {
2838 int dp = 0;
2839 for (Loop* lp = this->parent(); lp != nullptr; lp = lp->parent())
2840 dp++;
2841 return dp;
2842 }
2843
2844 #ifndef PRODUCT
2845 // ------------------------------------------------------------------
2846 // ciTypeFlow::Loop::print
2847 void ciTypeFlow::Loop::print(outputStream* st, int indent) const {
2848 for (int i = 0; i < indent; i++) st->print(" ");
2849 st->print("%d<-%d %s",
2850 is_root() ? 0 : this->head()->pre_order(),
2851 is_root() ? 0 : this->tail()->pre_order(),
2852 is_irreducible()?" irr":"");
2853 st->print(" defs: ");
2854 def_locals()->print_on(st, _head->outer()->method()->max_locals());
2855 st->cr();
2856 for (Loop* ch = child(); ch != nullptr; ch = ch->sibling())
2857 ch->print(st, indent+2);
2858 }
2859 #endif
2860
2861 // ------------------------------------------------------------------
2862 // ciTypeFlow::df_flow_types
2863 //
2864 // Perform the depth first type flow analysis. Helper for flow_types.
2865 void ciTypeFlow::df_flow_types(Block* start,
2866 bool do_flow,
2867 StateVector* temp_vector,
2868 JsrSet* temp_set) {
2869 int dft_len = 100;
2870 GrowableArray<Block*> stk(dft_len);
2871
2872 ciBlock* dummy = _method->get_method_blocks()->make_dummy_block();
2873 JsrSet* root_set = new JsrSet(0);
2874 Block* root_head = new (arena()) Block(this, dummy, root_set);
2875 Block* root_tail = new (arena()) Block(this, dummy, root_set);
2876 root_head->set_pre_order(0);
2877 root_head->set_post_order(0);
2878 root_tail->set_pre_order(max_jint);
2879 root_tail->set_post_order(max_jint);
2880 set_loop_tree_root(new (arena()) Loop(root_head, root_tail));
2881
2882 stk.push(start);
2883
2884 _next_pre_order = 0; // initialize pre_order counter
2885 _rpo_list = nullptr;
2886 int next_po = 0; // initialize post_order counter
2887
2888 // Compute RPO and the control flow graph
2889 int size;
2890 while ((size = stk.length()) > 0) {
2891 Block* blk = stk.top(); // Leave node on stack
2892 if (!blk->is_visited()) {
2893 // forward arc in graph
2894 assert (!blk->has_pre_order(), "");
2895 blk->set_next_pre_order();
2896
2897 if (_next_pre_order >= (int)Compile::current()->max_node_limit() / 2) {
2898 // Too many basic blocks. Bail out.
2899 // This can happen when try/finally constructs are nested to depth N,
2900 // and there is O(2**N) cloning of jsr bodies. See bug 4697245!
2901 // "MaxNodeLimit / 2" is used because probably the parser will
2902 // generate at least twice that many nodes and bail out.
2903 record_failure("too many basic blocks");
2904 return;
2905 }
2906 if (do_flow) {
2907 flow_block(blk, temp_vector, temp_set);
2908 if (failing()) return; // Watch for bailouts.
2909 }
2910 } else if (!blk->is_post_visited()) {
2911 // cross or back arc
2912 for (SuccIter iter(blk); !iter.done(); iter.next()) {
2913 Block* succ = iter.succ();
2914 if (!succ->is_visited()) {
2915 stk.push(succ);
2916 }
2917 }
2918 if (stk.length() == size) {
2919 // There were no additional children, post visit node now
2920 stk.pop(); // Remove node from stack
2921
2922 build_loop_tree(blk);
2923 blk->set_post_order(next_po++); // Assign post order
2924 prepend_to_rpo_list(blk);
2925 assert(blk->is_post_visited(), "");
2926
2927 if (blk->is_loop_head() && !blk->is_on_work_list()) {
2928 // Assume loop heads need more data flow
2929 add_to_work_list(blk);
2930 }
2931 }
2932 } else {
2933 stk.pop(); // Remove post-visited node from stack
2934 }
2935 }
2936 }
2937
2938 // ------------------------------------------------------------------
2939 // ciTypeFlow::flow_types
2940 //
2941 // Perform the type flow analysis, creating and cloning Blocks as
2942 // necessary.
2943 void ciTypeFlow::flow_types() {
2944 ResourceMark rm;
2945 StateVector* temp_vector = new StateVector(this);
2946 JsrSet* temp_set = new JsrSet(4);
2947
2948 // Create the method entry block.
2949 Block* start = block_at(start_bci(), temp_set);
2950
2951 // Load the initial state into it.
2952 const StateVector* start_state = get_start_state();
2953 if (failing()) return;
2954 start->meet(start_state);
2955
2956 // Depth first visit
2957 df_flow_types(start, true /*do flow*/, temp_vector, temp_set);
2958
2959 if (failing()) return;
2960 assert(_rpo_list == start, "must be start");
2961
2962 // Any loops found?
2963 if (loop_tree_root()->child() != nullptr &&
2964 env()->comp_level() >= CompLevel_full_optimization) {
2965 // Loop optimizations are not performed on Tier1 compiles.
2966
2967 bool changed = clone_loop_heads(temp_vector, temp_set);
2968
2969 // If some loop heads were cloned, recompute postorder and loop tree
2970 if (changed) {
2971 loop_tree_root()->set_child(nullptr);
2972 for (Block* blk = _rpo_list; blk != nullptr;) {
2973 Block* next = blk->rpo_next();
2974 blk->df_init();
2975 blk = next;
2976 }
2977 df_flow_types(start, false /*no flow*/, temp_vector, temp_set);
2978 }
2979 }
2980
2981 if (CITraceTypeFlow) {
2982 tty->print_cr("\nLoop tree");
2983 loop_tree_root()->print();
2984 }
2985
2986 // Continue flow analysis until fixed point reached
2987
2988 debug_only(int max_block = _next_pre_order;)
2989
2990 while (!work_list_empty()) {
2991 Block* blk = work_list_next();
2992 assert (blk->has_post_order(), "post order assigned above");
2993
2994 flow_block(blk, temp_vector, temp_set);
2995
2996 assert (max_block == _next_pre_order, "no new blocks");
2997 assert (!failing(), "no more bailouts");
2998 }
2999 }
3000
3001 // ------------------------------------------------------------------
3002 // ciTypeFlow::map_blocks
3003 //
3004 // Create the block map, which indexes blocks in reverse post-order.
3005 void ciTypeFlow::map_blocks() {
3006 assert(_block_map == nullptr, "single initialization");
3007 int block_ct = _next_pre_order;
3008 _block_map = NEW_ARENA_ARRAY(arena(), Block*, block_ct);
3009 assert(block_ct == block_count(), "");
3010
3011 Block* blk = _rpo_list;
3012 for (int m = 0; m < block_ct; m++) {
3013 int rpo = blk->rpo();
3014 assert(rpo == m, "should be sequential");
3015 _block_map[rpo] = blk;
3016 blk = blk->rpo_next();
3017 }
3018 assert(blk == nullptr, "should be done");
3019
3020 for (int j = 0; j < block_ct; j++) {
3021 assert(_block_map[j] != nullptr, "must not drop any blocks");
3022 Block* block = _block_map[j];
3023 // Remove dead blocks from successor lists:
3024 for (int e = 0; e <= 1; e++) {
3025 GrowableArray<Block*>* l = e? block->exceptions(): block->successors();
3026 for (int k = 0; k < l->length(); k++) {
3027 Block* s = l->at(k);
3028 if (!s->has_post_order()) {
3029 if (CITraceTypeFlow) {
3030 tty->print("Removing dead %s successor of #%d: ", (e? "exceptional": "normal"), block->pre_order());
3031 s->print_value_on(tty);
3032 tty->cr();
3033 }
3034 l->remove(s);
3035 --k;
3036 }
3037 }
3038 }
3039 }
3040 }
3041
3042 // ------------------------------------------------------------------
3043 // ciTypeFlow::get_block_for
3044 //
3045 // Find a block with this ciBlock which has a compatible JsrSet.
3046 // If no such block exists, create it, unless the option is no_create.
3047 // If the option is create_backedge_copy, always create a fresh backedge copy.
3048 ciTypeFlow::Block* ciTypeFlow::get_block_for(int ciBlockIndex, ciTypeFlow::JsrSet* jsrs, CreateOption option) {
3049 Arena* a = arena();
3050 GrowableArray<Block*>* blocks = _idx_to_blocklist[ciBlockIndex];
3051 if (blocks == nullptr) {
3052 // Query only?
3053 if (option == no_create) return nullptr;
3054
3055 // Allocate the growable array.
3056 blocks = new (a) GrowableArray<Block*>(a, 4, 0, nullptr);
3057 _idx_to_blocklist[ciBlockIndex] = blocks;
3058 }
3059
3060 if (option != create_backedge_copy) {
3061 int len = blocks->length();
3062 for (int i = 0; i < len; i++) {
3063 Block* block = blocks->at(i);
3064 if (!block->is_backedge_copy() && block->is_compatible_with(jsrs)) {
3065 return block;
3066 }
3067 }
3068 }
3069
3070 // Query only?
3071 if (option == no_create) return nullptr;
3072
3073 // We did not find a compatible block. Create one.
3074 Block* new_block = new (a) Block(this, _method->get_method_blocks()->block(ciBlockIndex), jsrs);
3075 if (option == create_backedge_copy) new_block->set_backedge_copy(true);
3076 blocks->append(new_block);
3077 return new_block;
3078 }
3079
3080 // ------------------------------------------------------------------
3081 // ciTypeFlow::backedge_copy_count
3082 //
3083 int ciTypeFlow::backedge_copy_count(int ciBlockIndex, ciTypeFlow::JsrSet* jsrs) const {
3084 GrowableArray<Block*>* blocks = _idx_to_blocklist[ciBlockIndex];
3085
3086 if (blocks == nullptr) {
3087 return 0;
3088 }
3089
3090 int count = 0;
3091 int len = blocks->length();
3092 for (int i = 0; i < len; i++) {
3093 Block* block = blocks->at(i);
3094 if (block->is_backedge_copy() && block->is_compatible_with(jsrs)) {
3095 count++;
3096 }
3097 }
3098
3099 return count;
3100 }
3101
3102 // ------------------------------------------------------------------
3103 // ciTypeFlow::do_flow
3104 //
3105 // Perform type inference flow analysis.
3106 void ciTypeFlow::do_flow() {
3107 if (CITraceTypeFlow) {
3108 tty->print_cr("\nPerforming flow analysis on method");
3109 method()->print();
3110 if (is_osr_flow()) tty->print(" at OSR bci %d", start_bci());
3111 tty->cr();
3112 method()->print_codes();
3113 }
3114 if (CITraceTypeFlow) {
3115 tty->print_cr("Initial CI Blocks");
3116 print_on(tty);
3117 }
3118 flow_types();
3119 // Watch for bailouts.
3120 if (failing()) {
3121 return;
3122 }
3123
3124 map_blocks();
3125
3126 if (CIPrintTypeFlow || CITraceTypeFlow) {
3127 rpo_print_on(tty);
3128 }
3129 }
3130
3131 // ------------------------------------------------------------------
3132 // ciTypeFlow::is_dominated_by
3133 //
3134 // Determine if the instruction at bci is dominated by the instruction at dom_bci.
3135 bool ciTypeFlow::is_dominated_by(int bci, int dom_bci) {
3136 assert(!method()->has_jsrs(), "jsrs are not supported");
3137
3138 ResourceMark rm;
3139 JsrSet* jsrs = new ciTypeFlow::JsrSet();
3140 int index = _method->get_method_blocks()->block_containing(bci)->index();
3141 int dom_index = _method->get_method_blocks()->block_containing(dom_bci)->index();
3142 Block* block = get_block_for(index, jsrs, ciTypeFlow::no_create);
3143 Block* dom_block = get_block_for(dom_index, jsrs, ciTypeFlow::no_create);
3144
3145 // Start block dominates all other blocks
3146 if (start_block()->rpo() == dom_block->rpo()) {
3147 return true;
3148 }
3149
3150 // Dominated[i] is true if block i is dominated by dom_block
3151 int num_blocks = block_count();
3152 bool* dominated = NEW_RESOURCE_ARRAY(bool, num_blocks);
3153 for (int i = 0; i < num_blocks; ++i) {
3154 dominated[i] = true;
3155 }
3156 dominated[start_block()->rpo()] = false;
3157
3158 // Iterative dominator algorithm
3159 bool changed = true;
3160 while (changed) {
3161 changed = false;
3162 // Use reverse postorder iteration
3163 for (Block* blk = _rpo_list; blk != nullptr; blk = blk->rpo_next()) {
3164 if (blk->is_start()) {
3165 // Ignore start block
3166 continue;
3167 }
3168 // The block is dominated if it is the dominating block
3169 // itself or if all predecessors are dominated.
3170 int index = blk->rpo();
3171 bool dom = (index == dom_block->rpo());
3172 if (!dom) {
3173 // Check if all predecessors are dominated
3174 dom = true;
3175 for (int i = 0; i < blk->predecessors()->length(); ++i) {
3176 Block* pred = blk->predecessors()->at(i);
3177 if (!dominated[pred->rpo()]) {
3178 dom = false;
3179 break;
3180 }
3181 }
3182 }
3183 // Update dominator information
3184 if (dominated[index] != dom) {
3185 changed = true;
3186 dominated[index] = dom;
3187 }
3188 }
3189 }
3190 // block dominated by dom_block?
3191 return dominated[block->rpo()];
3192 }
3193
3194 // ------------------------------------------------------------------
3195 // ciTypeFlow::record_failure()
3196 // The ciTypeFlow object keeps track of failure reasons separately from the ciEnv.
3197 // This is required because there is not a 1-1 relation between the ciEnv and
3198 // the TypeFlow passes within a compilation task. For example, if the compiler
3199 // is considering inlining a method, it will request a TypeFlow. If that fails,
3200 // the compilation as a whole may continue without the inlining. Some TypeFlow
3201 // requests are not optional; if they fail the requestor is responsible for
3202 // copying the failure reason up to the ciEnv. (See Parse::Parse.)
3203 void ciTypeFlow::record_failure(const char* reason) {
3204 if (env()->log() != nullptr) {
3205 env()->log()->elem("failure reason='%s' phase='typeflow'", reason);
3206 }
3207 if (_failure_reason == nullptr) {
3208 // Record the first failure reason.
3209 _failure_reason = reason;
3210 }
3211 }
3212
3213 ciType* ciTypeFlow::mark_as_null_free(ciType* type) {
3214 // Wrap the type to carry the information that it is null-free
3215 return env()->make_null_free_wrapper(type);
3216 }
3217
3218 #ifndef PRODUCT
3219 void ciTypeFlow::print() const { print_on(tty); }
3220
3221 // ------------------------------------------------------------------
3222 // ciTypeFlow::print_on
3223 void ciTypeFlow::print_on(outputStream* st) const {
3224 // Walk through CI blocks
3225 st->print_cr("********************************************************");
3226 st->print ("TypeFlow for ");
3227 method()->name()->print_symbol_on(st);
3228 int limit_bci = code_size();
3229 st->print_cr(" %d bytes", limit_bci);
3230 ciMethodBlocks* mblks = _method->get_method_blocks();
3231 ciBlock* current = nullptr;
3232 for (int bci = 0; bci < limit_bci; bci++) {
3233 ciBlock* blk = mblks->block_containing(bci);
3234 if (blk != nullptr && blk != current) {
3235 current = blk;
3236 current->print_on(st);
3237
3238 GrowableArray<Block*>* blocks = _idx_to_blocklist[blk->index()];
3239 int num_blocks = (blocks == nullptr) ? 0 : blocks->length();
3240
3241 if (num_blocks == 0) {
3242 st->print_cr(" No Blocks");
3243 } else {
3244 for (int i = 0; i < num_blocks; i++) {
3245 Block* block = blocks->at(i);
3246 block->print_on(st);
3247 }
3248 }
3249 st->print_cr("--------------------------------------------------------");
3250 st->cr();
3251 }
3252 }
3253 st->print_cr("********************************************************");
3254 st->cr();
3255 }
3256
3257 void ciTypeFlow::rpo_print_on(outputStream* st) const {
3258 st->print_cr("********************************************************");
3259 st->print ("TypeFlow for ");
3260 method()->name()->print_symbol_on(st);
3261 int limit_bci = code_size();
3262 st->print_cr(" %d bytes", limit_bci);
3263 for (Block* blk = _rpo_list; blk != nullptr; blk = blk->rpo_next()) {
3264 blk->print_on(st);
3265 st->print_cr("--------------------------------------------------------");
3266 st->cr();
3267 }
3268 st->print_cr("********************************************************");
3269 st->cr();
3270 }
3271 #endif