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 BasicType basic_type = str->get_basic_type_for_constant_at(cp_index);
781 if (is_reference_type(basic_type)) {
782 ciObject* obj = con.as_object();
783 if (obj->is_null_object()) {
784 push_null();
785 } else {
786 assert(obj->is_instance() || obj->is_array(), "must be java_mirror of klass");
787 ciType* type = obj->klass();
788 if (type->is_inlinetype()) {
789 type = outer()->mark_as_null_free(type);
790 }
791 push(type);
792 }
793 } else {
794 assert(basic_type == con.basic_type() || con.basic_type() == T_OBJECT,
795 "not a boxed form: %s vs %s", type2name(basic_type), type2name(con.basic_type()));
796 push_translate(ciType::make(basic_type));
797 }
798 } else {
799 // OutOfMemoryError in the CI while loading a String constant.
800 push_null();
801 outer()->record_failure("ldc did not link");
802 }
803 }
804
805 // ------------------------------------------------------------------
806 // ciTypeFlow::StateVector::do_multianewarray
807 void ciTypeFlow::StateVector::do_multianewarray(ciBytecodeStream* str) {
808 int dimensions = str->get_dimensions();
809 bool will_link;
810 ciArrayKlass* array_klass = str->get_klass(will_link)->as_array_klass();
811 if (!will_link) {
812 trap(str, array_klass, str->get_klass_index());
813 } else {
814 for (int i = 0; i < dimensions; i++) {
815 pop_int();
816 }
817 push_object(array_klass);
818 }
819 }
820
821 // ------------------------------------------------------------------
822 // ciTypeFlow::StateVector::do_new
823 void ciTypeFlow::StateVector::do_new(ciBytecodeStream* str) {
824 bool will_link;
825 ciKlass* klass = str->get_klass(will_link);
826 if (!will_link || str->is_unresolved_klass()) {
827 trap(str, klass, str->get_klass_index());
828 } else {
829 push_object(klass);
830 }
831 }
832
833 // ------------------------------------------------------------------
834 // ciTypeFlow::StateVector::do_newarray
835 void ciTypeFlow::StateVector::do_newarray(ciBytecodeStream* str) {
836 pop_int();
837 ciKlass* klass = ciTypeArrayKlass::make((BasicType)str->get_index());
838 push_object(klass);
839 }
840
841 // ------------------------------------------------------------------
842 // ciTypeFlow::StateVector::do_putfield
843 void ciTypeFlow::StateVector::do_putfield(ciBytecodeStream* str) {
844 do_putstatic(str);
845 if (_trap_bci != -1) return; // unloaded field holder, etc.
846 // could add assert here for type of object.
847 pop_object();
848 }
849
850 // ------------------------------------------------------------------
851 // ciTypeFlow::StateVector::do_putstatic
852 void ciTypeFlow::StateVector::do_putstatic(ciBytecodeStream* str) {
853 bool will_link;
854 ciField* field = str->get_field(will_link);
855 if (!will_link) {
856 trap(str, field->holder(), str->get_field_holder_index());
857 } else {
858 ciType* field_type = field->type();
859 ciType* type = pop_value();
860 // Do I want to check this type?
861 // assert(type->is_subtype_of(field_type), "bad type for field value");
862 if (field_type->is_two_word()) {
863 ciType* type2 = pop_value();
864 assert(type2->is_two_word(), "must be 2nd half");
865 assert(type == half_type(type2), "must be 2nd half");
866 }
867 }
868 }
869
870 // ------------------------------------------------------------------
871 // ciTypeFlow::StateVector::do_ret
872 void ciTypeFlow::StateVector::do_ret(ciBytecodeStream* str) {
873 Cell index = local(str->get_index());
874
875 ciType* address = type_at(index);
876 assert(address->is_return_address(), "bad return address");
877 set_type_at(index, bottom_type());
878 }
879
880 // ------------------------------------------------------------------
881 // ciTypeFlow::StateVector::trap
882 //
883 // Stop interpretation of this path with a trap.
884 void ciTypeFlow::StateVector::trap(ciBytecodeStream* str, ciKlass* klass, int index) {
885 _trap_bci = str->cur_bci();
886 _trap_index = index;
887
888 // Log information about this trap:
889 CompileLog* log = outer()->env()->log();
890 if (log != nullptr) {
891 int mid = log->identify(outer()->method());
892 int kid = (klass == nullptr)? -1: log->identify(klass);
893 log->begin_elem("uncommon_trap method='%d' bci='%d'", mid, str->cur_bci());
894 char buf[100];
895 log->print(" %s", Deoptimization::format_trap_request(buf, sizeof(buf),
896 index));
897 if (kid >= 0)
898 log->print(" klass='%d'", kid);
899 log->end_elem();
900 }
901 }
902
903 // ------------------------------------------------------------------
904 // ciTypeFlow::StateVector::do_null_assert
905 // Corresponds to graphKit::do_null_assert.
906 void ciTypeFlow::StateVector::do_null_assert(ciKlass* unloaded_klass) {
907 if (unloaded_klass->is_loaded()) {
908 // We failed to link, but we can still compute with this class,
909 // since it is loaded somewhere. The compiler will uncommon_trap
910 // if the object is not null, but the typeflow pass can not assume
911 // that the object will be null, otherwise it may incorrectly tell
912 // the parser that an object is known to be null. 4761344, 4807707
913 push_object(unloaded_klass);
914 } else {
915 // The class is not loaded anywhere. It is safe to model the
916 // null in the typestates, because we can compile in a null check
917 // which will deoptimize us if someone manages to load the
918 // class later.
919 push_null();
920 }
921 }
922
923
924 // ------------------------------------------------------------------
925 // ciTypeFlow::StateVector::apply_one_bytecode
926 //
927 // Apply the effect of one bytecode to this StateVector
928 bool ciTypeFlow::StateVector::apply_one_bytecode(ciBytecodeStream* str) {
929 _trap_bci = -1;
930 _trap_index = 0;
931
932 if (CITraceTypeFlow) {
933 tty->print_cr(">> Interpreting bytecode %d:%s", str->cur_bci(),
934 Bytecodes::name(str->cur_bc()));
935 }
936
937 switch(str->cur_bc()) {
938 case Bytecodes::_aaload: do_aload(str); break;
939
940 case Bytecodes::_aastore:
941 {
942 pop_object();
943 pop_int();
944 pop_objOrFlatArray();
945 break;
946 }
947 case Bytecodes::_aconst_null:
948 {
949 push_null();
950 break;
951 }
952 case Bytecodes::_aload: load_local_object(str->get_index()); break;
953 case Bytecodes::_aload_0: load_local_object(0); break;
954 case Bytecodes::_aload_1: load_local_object(1); break;
955 case Bytecodes::_aload_2: load_local_object(2); break;
956 case Bytecodes::_aload_3: load_local_object(3); break;
957
958 case Bytecodes::_anewarray:
959 {
960 pop_int();
961 bool will_link;
962 ciKlass* element_klass = str->get_klass(will_link);
963 if (!will_link) {
964 trap(str, element_klass, str->get_klass_index());
965 } else {
966 push_object(ciArrayKlass::make(element_klass));
967 }
968 break;
969 }
970 case Bytecodes::_areturn:
971 case Bytecodes::_ifnonnull:
972 case Bytecodes::_ifnull:
973 {
974 pop_object();
975 break;
976 }
977 case Bytecodes::_monitorenter:
978 {
979 pop_object();
980 set_monitor_count(monitor_count() + 1);
981 break;
982 }
983 case Bytecodes::_monitorexit:
984 {
985 pop_object();
986 assert(monitor_count() > 0, "must be a monitor to exit from");
987 set_monitor_count(monitor_count() - 1);
988 break;
989 }
990 case Bytecodes::_arraylength:
991 {
992 pop_array();
993 push_int();
994 break;
995 }
996 case Bytecodes::_astore: store_local_object(str->get_index()); break;
997 case Bytecodes::_astore_0: store_local_object(0); break;
998 case Bytecodes::_astore_1: store_local_object(1); break;
999 case Bytecodes::_astore_2: store_local_object(2); break;
1000 case Bytecodes::_astore_3: store_local_object(3); break;
1001
1002 case Bytecodes::_athrow:
1003 {
1004 NEEDS_CLEANUP;
1005 pop_object();
1006 break;
1007 }
1008 case Bytecodes::_baload:
1009 case Bytecodes::_caload:
1010 case Bytecodes::_iaload:
1011 case Bytecodes::_saload:
1012 {
1013 pop_int();
1014 ciTypeArrayKlass* array_klass = pop_typeArray();
1015 // Put assert here for right type?
1016 push_int();
1017 break;
1018 }
1019 case Bytecodes::_bastore:
1020 case Bytecodes::_castore:
1021 case Bytecodes::_iastore:
1022 case Bytecodes::_sastore:
1023 {
1024 pop_int();
1025 pop_int();
1026 pop_typeArray();
1027 // assert here?
1028 break;
1029 }
1030 case Bytecodes::_bipush:
1031 case Bytecodes::_iconst_m1:
1032 case Bytecodes::_iconst_0:
1033 case Bytecodes::_iconst_1:
1034 case Bytecodes::_iconst_2:
1035 case Bytecodes::_iconst_3:
1036 case Bytecodes::_iconst_4:
1037 case Bytecodes::_iconst_5:
1038 case Bytecodes::_sipush:
1039 {
1040 push_int();
1041 break;
1042 }
1043 case Bytecodes::_checkcast: do_checkcast(str); break;
1044
1045 case Bytecodes::_d2f:
1046 {
1047 pop_double();
1048 push_float();
1049 break;
1050 }
1051 case Bytecodes::_d2i:
1052 {
1053 pop_double();
1054 push_int();
1055 break;
1056 }
1057 case Bytecodes::_d2l:
1058 {
1059 pop_double();
1060 push_long();
1061 break;
1062 }
1063 case Bytecodes::_dadd:
1064 case Bytecodes::_ddiv:
1065 case Bytecodes::_dmul:
1066 case Bytecodes::_drem:
1067 case Bytecodes::_dsub:
1068 {
1069 pop_double();
1070 pop_double();
1071 push_double();
1072 break;
1073 }
1074 case Bytecodes::_daload:
1075 {
1076 pop_int();
1077 ciTypeArrayKlass* array_klass = pop_typeArray();
1078 // Put assert here for right type?
1079 push_double();
1080 break;
1081 }
1082 case Bytecodes::_dastore:
1083 {
1084 pop_double();
1085 pop_int();
1086 pop_typeArray();
1087 // assert here?
1088 break;
1089 }
1090 case Bytecodes::_dcmpg:
1091 case Bytecodes::_dcmpl:
1092 {
1093 pop_double();
1094 pop_double();
1095 push_int();
1096 break;
1097 }
1098 case Bytecodes::_dconst_0:
1099 case Bytecodes::_dconst_1:
1100 {
1101 push_double();
1102 break;
1103 }
1104 case Bytecodes::_dload: load_local_double(str->get_index()); break;
1105 case Bytecodes::_dload_0: load_local_double(0); break;
1106 case Bytecodes::_dload_1: load_local_double(1); break;
1107 case Bytecodes::_dload_2: load_local_double(2); break;
1108 case Bytecodes::_dload_3: load_local_double(3); break;
1109
1110 case Bytecodes::_dneg:
1111 {
1112 pop_double();
1113 push_double();
1114 break;
1115 }
1116 case Bytecodes::_dreturn:
1117 {
1118 pop_double();
1119 break;
1120 }
1121 case Bytecodes::_dstore: store_local_double(str->get_index()); break;
1122 case Bytecodes::_dstore_0: store_local_double(0); break;
1123 case Bytecodes::_dstore_1: store_local_double(1); break;
1124 case Bytecodes::_dstore_2: store_local_double(2); break;
1125 case Bytecodes::_dstore_3: store_local_double(3); break;
1126
1127 case Bytecodes::_dup:
1128 {
1129 push(type_at_tos());
1130 break;
1131 }
1132 case Bytecodes::_dup_x1:
1133 {
1134 ciType* value1 = pop_value();
1135 ciType* value2 = pop_value();
1136 push(value1);
1137 push(value2);
1138 push(value1);
1139 break;
1140 }
1141 case Bytecodes::_dup_x2:
1142 {
1143 ciType* value1 = pop_value();
1144 ciType* value2 = pop_value();
1145 ciType* value3 = pop_value();
1146 push(value1);
1147 push(value3);
1148 push(value2);
1149 push(value1);
1150 break;
1151 }
1152 case Bytecodes::_dup2:
1153 {
1154 ciType* value1 = pop_value();
1155 ciType* value2 = pop_value();
1156 push(value2);
1157 push(value1);
1158 push(value2);
1159 push(value1);
1160 break;
1161 }
1162 case Bytecodes::_dup2_x1:
1163 {
1164 ciType* value1 = pop_value();
1165 ciType* value2 = pop_value();
1166 ciType* value3 = pop_value();
1167 push(value2);
1168 push(value1);
1169 push(value3);
1170 push(value2);
1171 push(value1);
1172 break;
1173 }
1174 case Bytecodes::_dup2_x2:
1175 {
1176 ciType* value1 = pop_value();
1177 ciType* value2 = pop_value();
1178 ciType* value3 = pop_value();
1179 ciType* value4 = pop_value();
1180 push(value2);
1181 push(value1);
1182 push(value4);
1183 push(value3);
1184 push(value2);
1185 push(value1);
1186 break;
1187 }
1188 case Bytecodes::_f2d:
1189 {
1190 pop_float();
1191 push_double();
1192 break;
1193 }
1194 case Bytecodes::_f2i:
1195 {
1196 pop_float();
1197 push_int();
1198 break;
1199 }
1200 case Bytecodes::_f2l:
1201 {
1202 pop_float();
1203 push_long();
1204 break;
1205 }
1206 case Bytecodes::_fadd:
1207 case Bytecodes::_fdiv:
1208 case Bytecodes::_fmul:
1209 case Bytecodes::_frem:
1210 case Bytecodes::_fsub:
1211 {
1212 pop_float();
1213 pop_float();
1214 push_float();
1215 break;
1216 }
1217 case Bytecodes::_faload:
1218 {
1219 pop_int();
1220 ciTypeArrayKlass* array_klass = pop_typeArray();
1221 // Put assert here.
1222 push_float();
1223 break;
1224 }
1225 case Bytecodes::_fastore:
1226 {
1227 pop_float();
1228 pop_int();
1229 ciTypeArrayKlass* array_klass = pop_typeArray();
1230 // Put assert here.
1231 break;
1232 }
1233 case Bytecodes::_fcmpg:
1234 case Bytecodes::_fcmpl:
1235 {
1236 pop_float();
1237 pop_float();
1238 push_int();
1239 break;
1240 }
1241 case Bytecodes::_fconst_0:
1242 case Bytecodes::_fconst_1:
1243 case Bytecodes::_fconst_2:
1244 {
1245 push_float();
1246 break;
1247 }
1248 case Bytecodes::_fload: load_local_float(str->get_index()); break;
1249 case Bytecodes::_fload_0: load_local_float(0); break;
1250 case Bytecodes::_fload_1: load_local_float(1); break;
1251 case Bytecodes::_fload_2: load_local_float(2); break;
1252 case Bytecodes::_fload_3: load_local_float(3); break;
1253
1254 case Bytecodes::_fneg:
1255 {
1256 pop_float();
1257 push_float();
1258 break;
1259 }
1260 case Bytecodes::_freturn:
1261 {
1262 pop_float();
1263 break;
1264 }
1265 case Bytecodes::_fstore: store_local_float(str->get_index()); break;
1266 case Bytecodes::_fstore_0: store_local_float(0); break;
1267 case Bytecodes::_fstore_1: store_local_float(1); break;
1268 case Bytecodes::_fstore_2: store_local_float(2); break;
1269 case Bytecodes::_fstore_3: store_local_float(3); break;
1270
1271 case Bytecodes::_getfield: do_getfield(str); break;
1272 case Bytecodes::_getstatic: do_getstatic(str); break;
1273
1274 case Bytecodes::_goto:
1275 case Bytecodes::_goto_w:
1276 case Bytecodes::_nop:
1277 case Bytecodes::_return:
1278 {
1279 // do nothing.
1280 break;
1281 }
1282 case Bytecodes::_i2b:
1283 case Bytecodes::_i2c:
1284 case Bytecodes::_i2s:
1285 case Bytecodes::_ineg:
1286 {
1287 pop_int();
1288 push_int();
1289 break;
1290 }
1291 case Bytecodes::_i2d:
1292 {
1293 pop_int();
1294 push_double();
1295 break;
1296 }
1297 case Bytecodes::_i2f:
1298 {
1299 pop_int();
1300 push_float();
1301 break;
1302 }
1303 case Bytecodes::_i2l:
1304 {
1305 pop_int();
1306 push_long();
1307 break;
1308 }
1309 case Bytecodes::_iadd:
1310 case Bytecodes::_iand:
1311 case Bytecodes::_idiv:
1312 case Bytecodes::_imul:
1313 case Bytecodes::_ior:
1314 case Bytecodes::_irem:
1315 case Bytecodes::_ishl:
1316 case Bytecodes::_ishr:
1317 case Bytecodes::_isub:
1318 case Bytecodes::_iushr:
1319 case Bytecodes::_ixor:
1320 {
1321 pop_int();
1322 pop_int();
1323 push_int();
1324 break;
1325 }
1326 case Bytecodes::_if_acmpeq:
1327 case Bytecodes::_if_acmpne:
1328 {
1329 pop_object();
1330 pop_object();
1331 break;
1332 }
1333 case Bytecodes::_if_icmpeq:
1334 case Bytecodes::_if_icmpge:
1335 case Bytecodes::_if_icmpgt:
1336 case Bytecodes::_if_icmple:
1337 case Bytecodes::_if_icmplt:
1338 case Bytecodes::_if_icmpne:
1339 {
1340 pop_int();
1341 pop_int();
1342 break;
1343 }
1344 case Bytecodes::_ifeq:
1345 case Bytecodes::_ifle:
1346 case Bytecodes::_iflt:
1347 case Bytecodes::_ifge:
1348 case Bytecodes::_ifgt:
1349 case Bytecodes::_ifne:
1350 case Bytecodes::_ireturn:
1351 case Bytecodes::_lookupswitch:
1352 case Bytecodes::_tableswitch:
1353 {
1354 pop_int();
1355 break;
1356 }
1357 case Bytecodes::_iinc:
1358 {
1359 int lnum = str->get_index();
1360 check_int(local(lnum));
1361 store_to_local(lnum);
1362 break;
1363 }
1364 case Bytecodes::_iload: load_local_int(str->get_index()); break;
1365 case Bytecodes::_iload_0: load_local_int(0); break;
1366 case Bytecodes::_iload_1: load_local_int(1); break;
1367 case Bytecodes::_iload_2: load_local_int(2); break;
1368 case Bytecodes::_iload_3: load_local_int(3); break;
1369
1370 case Bytecodes::_instanceof:
1371 {
1372 // Check for uncommon trap:
1373 do_checkcast(str);
1374 pop_object();
1375 push_int();
1376 break;
1377 }
1378 case Bytecodes::_invokeinterface: do_invoke(str, true); break;
1379 case Bytecodes::_invokespecial: do_invoke(str, true); break;
1380 case Bytecodes::_invokestatic: do_invoke(str, false); break;
1381 case Bytecodes::_invokevirtual: do_invoke(str, true); break;
1382 case Bytecodes::_invokedynamic: do_invoke(str, false); break;
1383
1384 case Bytecodes::_istore: store_local_int(str->get_index()); break;
1385 case Bytecodes::_istore_0: store_local_int(0); break;
1386 case Bytecodes::_istore_1: store_local_int(1); break;
1387 case Bytecodes::_istore_2: store_local_int(2); break;
1388 case Bytecodes::_istore_3: store_local_int(3); break;
1389
1390 case Bytecodes::_jsr:
1391 case Bytecodes::_jsr_w: do_jsr(str); break;
1392
1393 case Bytecodes::_l2d:
1394 {
1395 pop_long();
1396 push_double();
1397 break;
1398 }
1399 case Bytecodes::_l2f:
1400 {
1401 pop_long();
1402 push_float();
1403 break;
1404 }
1405 case Bytecodes::_l2i:
1406 {
1407 pop_long();
1408 push_int();
1409 break;
1410 }
1411 case Bytecodes::_ladd:
1412 case Bytecodes::_land:
1413 case Bytecodes::_ldiv:
1414 case Bytecodes::_lmul:
1415 case Bytecodes::_lor:
1416 case Bytecodes::_lrem:
1417 case Bytecodes::_lsub:
1418 case Bytecodes::_lxor:
1419 {
1420 pop_long();
1421 pop_long();
1422 push_long();
1423 break;
1424 }
1425 case Bytecodes::_laload:
1426 {
1427 pop_int();
1428 ciTypeArrayKlass* array_klass = pop_typeArray();
1429 // Put assert here for right type?
1430 push_long();
1431 break;
1432 }
1433 case Bytecodes::_lastore:
1434 {
1435 pop_long();
1436 pop_int();
1437 pop_typeArray();
1438 // assert here?
1439 break;
1440 }
1441 case Bytecodes::_lcmp:
1442 {
1443 pop_long();
1444 pop_long();
1445 push_int();
1446 break;
1447 }
1448 case Bytecodes::_lconst_0:
1449 case Bytecodes::_lconst_1:
1450 {
1451 push_long();
1452 break;
1453 }
1454 case Bytecodes::_ldc:
1455 case Bytecodes::_ldc_w:
1456 case Bytecodes::_ldc2_w:
1457 {
1458 do_ldc(str);
1459 break;
1460 }
1461
1462 case Bytecodes::_lload: load_local_long(str->get_index()); break;
1463 case Bytecodes::_lload_0: load_local_long(0); break;
1464 case Bytecodes::_lload_1: load_local_long(1); break;
1465 case Bytecodes::_lload_2: load_local_long(2); break;
1466 case Bytecodes::_lload_3: load_local_long(3); break;
1467
1468 case Bytecodes::_lneg:
1469 {
1470 pop_long();
1471 push_long();
1472 break;
1473 }
1474 case Bytecodes::_lreturn:
1475 {
1476 pop_long();
1477 break;
1478 }
1479 case Bytecodes::_lshl:
1480 case Bytecodes::_lshr:
1481 case Bytecodes::_lushr:
1482 {
1483 pop_int();
1484 pop_long();
1485 push_long();
1486 break;
1487 }
1488 case Bytecodes::_lstore: store_local_long(str->get_index()); break;
1489 case Bytecodes::_lstore_0: store_local_long(0); break;
1490 case Bytecodes::_lstore_1: store_local_long(1); break;
1491 case Bytecodes::_lstore_2: store_local_long(2); break;
1492 case Bytecodes::_lstore_3: store_local_long(3); break;
1493
1494 case Bytecodes::_multianewarray: do_multianewarray(str); break;
1495
1496 case Bytecodes::_new: do_new(str); break;
1497
1498 case Bytecodes::_newarray: do_newarray(str); break;
1499
1500 case Bytecodes::_pop:
1501 {
1502 pop();
1503 break;
1504 }
1505 case Bytecodes::_pop2:
1506 {
1507 pop();
1508 pop();
1509 break;
1510 }
1511
1512 case Bytecodes::_putfield: do_putfield(str); break;
1513 case Bytecodes::_putstatic: do_putstatic(str); break;
1514
1515 case Bytecodes::_ret: do_ret(str); break;
1516
1517 case Bytecodes::_swap:
1518 {
1519 ciType* value1 = pop_value();
1520 ciType* value2 = pop_value();
1521 push(value1);
1522 push(value2);
1523 break;
1524 }
1525
1526 case Bytecodes::_wide:
1527 default:
1528 {
1529 // The iterator should skip this.
1530 ShouldNotReachHere();
1531 break;
1532 }
1533 }
1534
1535 if (CITraceTypeFlow) {
1536 print_on(tty);
1537 }
1538
1539 return (_trap_bci != -1);
1540 }
1541
1542 #ifndef PRODUCT
1543 // ------------------------------------------------------------------
1544 // ciTypeFlow::StateVector::print_cell_on
1545 void ciTypeFlow::StateVector::print_cell_on(outputStream* st, Cell c) const {
1546 ciType* type = type_at(c)->unwrap();
1547 if (type == top_type()) {
1548 st->print("top");
1549 } else if (type == bottom_type()) {
1550 st->print("bottom");
1551 } else if (type == null_type()) {
1552 st->print("null");
1553 } else if (type == long2_type()) {
1554 st->print("long2");
1555 } else if (type == double2_type()) {
1556 st->print("double2");
1557 } else if (is_int(type)) {
1558 st->print("int");
1559 } else if (is_long(type)) {
1560 st->print("long");
1561 } else if (is_float(type)) {
1562 st->print("float");
1563 } else if (is_double(type)) {
1564 st->print("double");
1565 } else if (type->is_return_address()) {
1566 st->print("address(%d)", type->as_return_address()->bci());
1567 } else {
1568 if (type->is_klass()) {
1569 type->as_klass()->name()->print_symbol_on(st);
1570 } else {
1571 st->print("UNEXPECTED TYPE");
1572 type->print();
1573 }
1574 }
1575 }
1576
1577 // ------------------------------------------------------------------
1578 // ciTypeFlow::StateVector::print_on
1579 void ciTypeFlow::StateVector::print_on(outputStream* st) const {
1580 int num_locals = _outer->max_locals();
1581 int num_stack = stack_size();
1582 int num_monitors = monitor_count();
1583 st->print_cr(" State : locals %d, stack %d, monitors %d", num_locals, num_stack, num_monitors);
1584 if (num_stack >= 0) {
1585 int i;
1586 for (i = 0; i < num_locals; i++) {
1587 st->print(" local %2d : ", i);
1588 print_cell_on(st, local(i));
1589 st->cr();
1590 }
1591 for (i = 0; i < num_stack; i++) {
1592 st->print(" stack %2d : ", i);
1593 print_cell_on(st, stack(i));
1594 st->cr();
1595 }
1596 }
1597 }
1598 #endif
1599
1600
1601 // ------------------------------------------------------------------
1602 // ciTypeFlow::SuccIter::next
1603 //
1604 void ciTypeFlow::SuccIter::next() {
1605 int succ_ct = _pred->successors()->length();
1606 int next = _index + 1;
1607 if (next < succ_ct) {
1608 _index = next;
1609 _succ = _pred->successors()->at(next);
1610 return;
1611 }
1612 for (int i = next - succ_ct; i < _pred->exceptions()->length(); i++) {
1613 // Do not compile any code for unloaded exception types.
1614 // Following compiler passes are responsible for doing this also.
1615 ciInstanceKlass* exception_klass = _pred->exc_klasses()->at(i);
1616 if (exception_klass->is_loaded()) {
1617 _index = next;
1618 _succ = _pred->exceptions()->at(i);
1619 return;
1620 }
1621 next++;
1622 }
1623 _index = -1;
1624 _succ = nullptr;
1625 }
1626
1627 // ------------------------------------------------------------------
1628 // ciTypeFlow::SuccIter::set_succ
1629 //
1630 void ciTypeFlow::SuccIter::set_succ(Block* succ) {
1631 int succ_ct = _pred->successors()->length();
1632 if (_index < succ_ct) {
1633 _pred->successors()->at_put(_index, succ);
1634 } else {
1635 int idx = _index - succ_ct;
1636 _pred->exceptions()->at_put(idx, succ);
1637 }
1638 }
1639
1640 // ciTypeFlow::Block
1641 //
1642 // A basic block.
1643
1644 // ------------------------------------------------------------------
1645 // ciTypeFlow::Block::Block
1646 ciTypeFlow::Block::Block(ciTypeFlow* outer,
1647 ciBlock *ciblk,
1648 ciTypeFlow::JsrSet* jsrs) : _predecessors(outer->arena(), 1, 0, nullptr) {
1649 _ciblock = ciblk;
1650 _exceptions = nullptr;
1651 _exc_klasses = nullptr;
1652 _successors = nullptr;
1653 _state = new (outer->arena()) StateVector(outer);
1654 JsrSet* new_jsrs =
1655 new (outer->arena()) JsrSet(outer->arena(), jsrs->size());
1656 jsrs->copy_into(new_jsrs);
1657 _jsrs = new_jsrs;
1658 _next = nullptr;
1659 _on_work_list = false;
1660 _backedge_copy = false;
1661 _has_monitorenter = false;
1662 _trap_bci = -1;
1663 _trap_index = 0;
1664 df_init();
1665
1666 if (CITraceTypeFlow) {
1667 tty->print_cr(">> Created new block");
1668 print_on(tty);
1669 }
1670
1671 assert(this->outer() == outer, "outer link set up");
1672 assert(!outer->have_block_count(), "must not have mapped blocks yet");
1673 }
1674
1675 // ------------------------------------------------------------------
1676 // ciTypeFlow::Block::df_init
1677 void ciTypeFlow::Block::df_init() {
1678 _pre_order = -1; assert(!has_pre_order(), "");
1679 _post_order = -1; assert(!has_post_order(), "");
1680 _loop = nullptr;
1681 _irreducible_loop_head = false;
1682 _irreducible_loop_secondary_entry = false;
1683 _rpo_next = nullptr;
1684 }
1685
1686 // ------------------------------------------------------------------
1687 // ciTypeFlow::Block::successors
1688 //
1689 // Get the successors for this Block.
1690 GrowableArray<ciTypeFlow::Block*>*
1691 ciTypeFlow::Block::successors(ciBytecodeStream* str,
1692 ciTypeFlow::StateVector* state,
1693 ciTypeFlow::JsrSet* jsrs) {
1694 if (_successors == nullptr) {
1695 if (CITraceTypeFlow) {
1696 tty->print(">> Computing successors for block ");
1697 print_value_on(tty);
1698 tty->cr();
1699 }
1700
1701 ciTypeFlow* analyzer = outer();
1702 Arena* arena = analyzer->arena();
1703 Block* block = nullptr;
1704 bool has_successor = !has_trap() &&
1705 (control() != ciBlock::fall_through_bci || limit() < analyzer->code_size());
1706 if (!has_successor) {
1707 _successors =
1708 new (arena) GrowableArray<Block*>(arena, 1, 0, nullptr);
1709 // No successors
1710 } else if (control() == ciBlock::fall_through_bci) {
1711 assert(str->cur_bci() == limit(), "bad block end");
1712 // This block simply falls through to the next.
1713 _successors =
1714 new (arena) GrowableArray<Block*>(arena, 1, 0, nullptr);
1715
1716 Block* block = analyzer->block_at(limit(), _jsrs);
1717 assert(_successors->length() == FALL_THROUGH, "");
1718 _successors->append(block);
1719 } else {
1720 int current_bci = str->cur_bci();
1721 int next_bci = str->next_bci();
1722 int branch_bci = -1;
1723 Block* target = nullptr;
1724 assert(str->next_bci() == limit(), "bad block end");
1725 // This block is not a simple fall-though. Interpret
1726 // the current bytecode to find our successors.
1727 switch (str->cur_bc()) {
1728 case Bytecodes::_ifeq: case Bytecodes::_ifne:
1729 case Bytecodes::_iflt: case Bytecodes::_ifge:
1730 case Bytecodes::_ifgt: case Bytecodes::_ifle:
1731 case Bytecodes::_if_icmpeq: case Bytecodes::_if_icmpne:
1732 case Bytecodes::_if_icmplt: case Bytecodes::_if_icmpge:
1733 case Bytecodes::_if_icmpgt: case Bytecodes::_if_icmple:
1734 case Bytecodes::_if_acmpeq: case Bytecodes::_if_acmpne:
1735 case Bytecodes::_ifnull: case Bytecodes::_ifnonnull:
1736 // Our successors are the branch target and the next bci.
1737 branch_bci = str->get_dest();
1738 _successors =
1739 new (arena) GrowableArray<Block*>(arena, 2, 0, nullptr);
1740 assert(_successors->length() == IF_NOT_TAKEN, "");
1741 _successors->append(analyzer->block_at(next_bci, jsrs));
1742 assert(_successors->length() == IF_TAKEN, "");
1743 _successors->append(analyzer->block_at(branch_bci, jsrs));
1744 break;
1745
1746 case Bytecodes::_goto:
1747 branch_bci = str->get_dest();
1748 _successors =
1749 new (arena) GrowableArray<Block*>(arena, 1, 0, nullptr);
1750 assert(_successors->length() == GOTO_TARGET, "");
1751 _successors->append(analyzer->block_at(branch_bci, jsrs));
1752 break;
1753
1754 case Bytecodes::_jsr:
1755 branch_bci = str->get_dest();
1756 _successors =
1757 new (arena) GrowableArray<Block*>(arena, 1, 0, nullptr);
1758 assert(_successors->length() == GOTO_TARGET, "");
1759 _successors->append(analyzer->block_at(branch_bci, jsrs));
1760 break;
1761
1762 case Bytecodes::_goto_w:
1763 case Bytecodes::_jsr_w:
1764 _successors =
1765 new (arena) GrowableArray<Block*>(arena, 1, 0, nullptr);
1766 assert(_successors->length() == GOTO_TARGET, "");
1767 _successors->append(analyzer->block_at(str->get_far_dest(), jsrs));
1768 break;
1769
1770 case Bytecodes::_tableswitch: {
1771 Bytecode_tableswitch tableswitch(str);
1772
1773 int len = tableswitch.length();
1774 _successors =
1775 new (arena) GrowableArray<Block*>(arena, len+1, 0, nullptr);
1776 int bci = current_bci + tableswitch.default_offset();
1777 Block* block = analyzer->block_at(bci, jsrs);
1778 assert(_successors->length() == SWITCH_DEFAULT, "");
1779 _successors->append(block);
1780 while (--len >= 0) {
1781 int bci = current_bci + tableswitch.dest_offset_at(len);
1782 block = analyzer->block_at(bci, jsrs);
1783 assert(_successors->length() >= SWITCH_CASES, "");
1784 _successors->append_if_missing(block);
1785 }
1786 break;
1787 }
1788
1789 case Bytecodes::_lookupswitch: {
1790 Bytecode_lookupswitch lookupswitch(str);
1791
1792 int npairs = lookupswitch.number_of_pairs();
1793 _successors =
1794 new (arena) GrowableArray<Block*>(arena, npairs+1, 0, nullptr);
1795 int bci = current_bci + lookupswitch.default_offset();
1796 Block* block = analyzer->block_at(bci, jsrs);
1797 assert(_successors->length() == SWITCH_DEFAULT, "");
1798 _successors->append(block);
1799 while(--npairs >= 0) {
1800 LookupswitchPair pair = lookupswitch.pair_at(npairs);
1801 int bci = current_bci + pair.offset();
1802 Block* block = analyzer->block_at(bci, jsrs);
1803 assert(_successors->length() >= SWITCH_CASES, "");
1804 _successors->append_if_missing(block);
1805 }
1806 break;
1807 }
1808
1809 case Bytecodes::_athrow:
1810 case Bytecodes::_ireturn:
1811 case Bytecodes::_lreturn:
1812 case Bytecodes::_freturn:
1813 case Bytecodes::_dreturn:
1814 case Bytecodes::_areturn:
1815 case Bytecodes::_return:
1816 _successors =
1817 new (arena) GrowableArray<Block*>(arena, 1, 0, nullptr);
1818 // No successors
1819 break;
1820
1821 case Bytecodes::_ret: {
1822 _successors =
1823 new (arena) GrowableArray<Block*>(arena, 1, 0, nullptr);
1824
1825 Cell local = state->local(str->get_index());
1826 ciType* return_address = state->type_at(local);
1827 assert(return_address->is_return_address(), "verify: wrong type");
1828 int bci = return_address->as_return_address()->bci();
1829 assert(_successors->length() == GOTO_TARGET, "");
1830 _successors->append(analyzer->block_at(bci, jsrs));
1831 break;
1832 }
1833
1834 case Bytecodes::_wide:
1835 default:
1836 ShouldNotReachHere();
1837 break;
1838 }
1839 }
1840
1841 // Set predecessor information
1842 for (int i = 0; i < _successors->length(); i++) {
1843 Block* block = _successors->at(i);
1844 block->predecessors()->append(this);
1845 }
1846 }
1847 return _successors;
1848 }
1849
1850 // ------------------------------------------------------------------
1851 // ciTypeFlow::Block:compute_exceptions
1852 //
1853 // Compute the exceptional successors and types for this Block.
1854 void ciTypeFlow::Block::compute_exceptions() {
1855 assert(_exceptions == nullptr && _exc_klasses == nullptr, "repeat");
1856
1857 if (CITraceTypeFlow) {
1858 tty->print(">> Computing exceptions for block ");
1859 print_value_on(tty);
1860 tty->cr();
1861 }
1862
1863 ciTypeFlow* analyzer = outer();
1864 Arena* arena = analyzer->arena();
1865
1866 // Any bci in the block will do.
1867 ciExceptionHandlerStream str(analyzer->method(), start());
1868
1869 // Allocate our growable arrays.
1870 int exc_count = str.count();
1871 _exceptions = new (arena) GrowableArray<Block*>(arena, exc_count, 0, nullptr);
1872 _exc_klasses = new (arena) GrowableArray<ciInstanceKlass*>(arena, exc_count,
1873 0, nullptr);
1874
1875 for ( ; !str.is_done(); str.next()) {
1876 ciExceptionHandler* handler = str.handler();
1877 int bci = handler->handler_bci();
1878 ciInstanceKlass* klass = nullptr;
1879 if (bci == -1) {
1880 // There is no catch all. It is possible to exit the method.
1881 break;
1882 }
1883 if (handler->is_catch_all()) {
1884 klass = analyzer->env()->Throwable_klass();
1885 } else {
1886 klass = handler->catch_klass();
1887 }
1888 Block* block = analyzer->block_at(bci, _jsrs);
1889 _exceptions->append(block);
1890 block->predecessors()->append(this);
1891 _exc_klasses->append(klass);
1892 }
1893 }
1894
1895 // ------------------------------------------------------------------
1896 // ciTypeFlow::Block::set_backedge_copy
1897 // Use this only to make a pre-existing public block into a backedge copy.
1898 void ciTypeFlow::Block::set_backedge_copy(bool z) {
1899 assert(z || (z == is_backedge_copy()), "cannot make a backedge copy public");
1900 _backedge_copy = z;
1901 }
1902
1903 // Analogous to PhaseIdealLoop::is_in_irreducible_loop
1904 bool ciTypeFlow::Block::is_in_irreducible_loop() const {
1905 if (!outer()->has_irreducible_entry()) {
1906 return false; // No irreducible loop in method.
1907 }
1908 Loop* lp = loop(); // Innermost loop containing block.
1909 if (lp == nullptr) {
1910 assert(!is_post_visited(), "must have enclosing loop once post-visited");
1911 return false; // Not yet processed, so we do not know, yet.
1912 }
1913 // Walk all the way up the loop-tree, search for an irreducible loop.
1914 do {
1915 if (lp->is_irreducible()) {
1916 return true; // We are in irreducible loop.
1917 }
1918 if (lp->head()->pre_order() == 0) {
1919 return false; // Found root loop, terminate.
1920 }
1921 lp = lp->parent();
1922 } while (lp != nullptr);
1923 // We have "lp->parent() == nullptr", which happens only for infinite loops,
1924 // where no parent is attached to the loop. We did not find any irreducible
1925 // loop from this block out to lp. Thus lp only has one entry, and no exit
1926 // (it is infinite and reducible). We can always rewrite an infinite loop
1927 // that is nested inside other loops:
1928 // while(condition) { infinite_loop; }
1929 // with an equivalent program where the infinite loop is an outermost loop
1930 // that is not nested in any loop:
1931 // while(condition) { break; } infinite_loop;
1932 // Thus, we can understand lp as an outermost loop, and can terminate and
1933 // conclude: this block is in no irreducible loop.
1934 return false;
1935 }
1936
1937 // ------------------------------------------------------------------
1938 // ciTypeFlow::Block::is_clonable_exit
1939 //
1940 // At most 2 normal successors, one of which continues looping,
1941 // and all exceptional successors must exit.
1942 bool ciTypeFlow::Block::is_clonable_exit(ciTypeFlow::Loop* lp) {
1943 int normal_cnt = 0;
1944 int in_loop_cnt = 0;
1945 for (SuccIter iter(this); !iter.done(); iter.next()) {
1946 Block* succ = iter.succ();
1947 if (iter.is_normal_ctrl()) {
1948 if (++normal_cnt > 2) return false;
1949 if (lp->contains(succ->loop())) {
1950 if (++in_loop_cnt > 1) return false;
1951 }
1952 } else {
1953 if (lp->contains(succ->loop())) return false;
1954 }
1955 }
1956 return in_loop_cnt == 1;
1957 }
1958
1959 // ------------------------------------------------------------------
1960 // ciTypeFlow::Block::looping_succ
1961 //
1962 ciTypeFlow::Block* ciTypeFlow::Block::looping_succ(ciTypeFlow::Loop* lp) {
1963 assert(successors()->length() <= 2, "at most 2 normal successors");
1964 for (SuccIter iter(this); !iter.done(); iter.next()) {
1965 Block* succ = iter.succ();
1966 if (lp->contains(succ->loop())) {
1967 return succ;
1968 }
1969 }
1970 return nullptr;
1971 }
1972
1973 #ifndef PRODUCT
1974 // ------------------------------------------------------------------
1975 // ciTypeFlow::Block::print_value_on
1976 void ciTypeFlow::Block::print_value_on(outputStream* st) const {
1977 if (has_pre_order()) st->print("#%-2d ", pre_order());
1978 if (has_rpo()) st->print("rpo#%-2d ", rpo());
1979 st->print("[%d - %d)", start(), limit());
1980 if (is_loop_head()) st->print(" lphd");
1981 if (is_in_irreducible_loop()) st->print(" in_irred");
1982 if (is_irreducible_loop_head()) st->print(" irred_head");
1983 if (is_irreducible_loop_secondary_entry()) st->print(" irred_entry");
1984 if (_jsrs->size() > 0) { st->print("/"); _jsrs->print_on(st); }
1985 if (is_backedge_copy()) st->print("/backedge_copy");
1986 }
1987
1988 // ------------------------------------------------------------------
1989 // ciTypeFlow::Block::print_on
1990 void ciTypeFlow::Block::print_on(outputStream* st) const {
1991 if ((Verbose || WizardMode) && (limit() >= 0)) {
1992 // Don't print 'dummy' blocks (i.e. blocks with limit() '-1')
1993 outer()->method()->print_codes_on(start(), limit(), st);
1994 }
1995 st->print_cr(" ==================================================== ");
1996 st->print (" ");
1997 print_value_on(st);
1998 st->print(" Stored locals: "); def_locals()->print_on(st, outer()->method()->max_locals()); tty->cr();
1999 if (loop() && loop()->parent() != nullptr) {
2000 st->print(" loops:");
2001 Loop* lp = loop();
2002 do {
2003 st->print(" %d<-%d", lp->head()->pre_order(),lp->tail()->pre_order());
2004 if (lp->is_irreducible()) st->print("(ir)");
2005 lp = lp->parent();
2006 } while (lp->parent() != nullptr);
2007 }
2008 st->cr();
2009 _state->print_on(st);
2010 if (_successors == nullptr) {
2011 st->print_cr(" No successor information");
2012 } else {
2013 int num_successors = _successors->length();
2014 st->print_cr(" Successors : %d", num_successors);
2015 for (int i = 0; i < num_successors; i++) {
2016 Block* successor = _successors->at(i);
2017 st->print(" ");
2018 successor->print_value_on(st);
2019 st->cr();
2020 }
2021 }
2022 if (_predecessors.is_empty()) {
2023 st->print_cr(" No predecessor information");
2024 } else {
2025 int num_predecessors = _predecessors.length();
2026 st->print_cr(" Predecessors : %d", num_predecessors);
2027 for (int i = 0; i < num_predecessors; i++) {
2028 Block* predecessor = _predecessors.at(i);
2029 st->print(" ");
2030 predecessor->print_value_on(st);
2031 st->cr();
2032 }
2033 }
2034 if (_exceptions == nullptr) {
2035 st->print_cr(" No exception information");
2036 } else {
2037 int num_exceptions = _exceptions->length();
2038 st->print_cr(" Exceptions : %d", num_exceptions);
2039 for (int i = 0; i < num_exceptions; i++) {
2040 Block* exc_succ = _exceptions->at(i);
2041 ciInstanceKlass* exc_klass = _exc_klasses->at(i);
2042 st->print(" ");
2043 exc_succ->print_value_on(st);
2044 st->print(" -- ");
2045 exc_klass->name()->print_symbol_on(st);
2046 st->cr();
2047 }
2048 }
2049 if (has_trap()) {
2050 st->print_cr(" Traps on %d with trap index %d", trap_bci(), trap_index());
2051 }
2052 st->print_cr(" ==================================================== ");
2053 }
2054 #endif
2055
2056 #ifndef PRODUCT
2057 // ------------------------------------------------------------------
2058 // ciTypeFlow::LocalSet::print_on
2059 void ciTypeFlow::LocalSet::print_on(outputStream* st, int limit) const {
2060 st->print("{");
2061 for (int i = 0; i < max; i++) {
2062 if (test(i)) st->print(" %d", i);
2063 }
2064 if (limit > max) {
2065 st->print(" %d..%d ", max, limit);
2066 }
2067 st->print(" }");
2068 }
2069 #endif
2070
2071 // ciTypeFlow
2072 //
2073 // This is a pass over the bytecodes which computes the following:
2074 // basic block structure
2075 // interpreter type-states (a la the verifier)
2076
2077 // ------------------------------------------------------------------
2078 // ciTypeFlow::ciTypeFlow
2079 ciTypeFlow::ciTypeFlow(ciEnv* env, ciMethod* method, int osr_bci) {
2080 _env = env;
2081 _method = method;
2082 _has_irreducible_entry = false;
2083 _osr_bci = osr_bci;
2084 _failure_reason = nullptr;
2085 assert(0 <= start_bci() && start_bci() < code_size() , "correct osr_bci argument: 0 <= %d < %d", start_bci(), code_size());
2086 _work_list = nullptr;
2087
2088 int ciblock_count = _method->get_method_blocks()->num_blocks();
2089 _idx_to_blocklist = NEW_ARENA_ARRAY(arena(), GrowableArray<Block*>*, ciblock_count);
2090 for (int i = 0; i < ciblock_count; i++) {
2091 _idx_to_blocklist[i] = nullptr;
2092 }
2093 _block_map = nullptr; // until all blocks are seen
2094 _jsr_records = nullptr;
2095 }
2096
2097 // ------------------------------------------------------------------
2098 // ciTypeFlow::work_list_next
2099 //
2100 // Get the next basic block from our work list.
2101 ciTypeFlow::Block* ciTypeFlow::work_list_next() {
2102 assert(!work_list_empty(), "work list must not be empty");
2103 Block* next_block = _work_list;
2104 _work_list = next_block->next();
2105 next_block->set_next(nullptr);
2106 next_block->set_on_work_list(false);
2107 return next_block;
2108 }
2109
2110 // ------------------------------------------------------------------
2111 // ciTypeFlow::add_to_work_list
2112 //
2113 // Add a basic block to our work list.
2114 // List is sorted by decreasing postorder sort (same as increasing RPO)
2115 void ciTypeFlow::add_to_work_list(ciTypeFlow::Block* block) {
2116 assert(!block->is_on_work_list(), "must not already be on work list");
2117
2118 if (CITraceTypeFlow) {
2119 tty->print(">> Adding block ");
2120 block->print_value_on(tty);
2121 tty->print_cr(" to the work list : ");
2122 }
2123
2124 block->set_on_work_list(true);
2125
2126 // decreasing post order sort
2127
2128 Block* prev = nullptr;
2129 Block* current = _work_list;
2130 int po = block->post_order();
2131 while (current != nullptr) {
2132 if (!current->has_post_order() || po > current->post_order())
2133 break;
2134 prev = current;
2135 current = current->next();
2136 }
2137 if (prev == nullptr) {
2138 block->set_next(_work_list);
2139 _work_list = block;
2140 } else {
2141 block->set_next(current);
2142 prev->set_next(block);
2143 }
2144
2145 if (CITraceTypeFlow) {
2146 tty->cr();
2147 }
2148 }
2149
2150 // ------------------------------------------------------------------
2151 // ciTypeFlow::block_at
2152 //
2153 // Return the block beginning at bci which has a JsrSet compatible
2154 // with jsrs.
2155 ciTypeFlow::Block* ciTypeFlow::block_at(int bci, ciTypeFlow::JsrSet* jsrs, CreateOption option) {
2156 // First find the right ciBlock.
2157 if (CITraceTypeFlow) {
2158 tty->print(">> Requesting block for %d/", bci);
2159 jsrs->print_on(tty);
2160 tty->cr();
2161 }
2162
2163 ciBlock* ciblk = _method->get_method_blocks()->block_containing(bci);
2164 assert(ciblk->start_bci() == bci, "bad ciBlock boundaries");
2165 Block* block = get_block_for(ciblk->index(), jsrs, option);
2166
2167 assert(block == nullptr? (option == no_create): block->is_backedge_copy() == (option == create_backedge_copy), "create option consistent with result");
2168
2169 if (CITraceTypeFlow) {
2170 if (block != nullptr) {
2171 tty->print(">> Found block ");
2172 block->print_value_on(tty);
2173 tty->cr();
2174 } else {
2175 tty->print_cr(">> No such block.");
2176 }
2177 }
2178
2179 return block;
2180 }
2181
2182 // ------------------------------------------------------------------
2183 // ciTypeFlow::make_jsr_record
2184 //
2185 // Make a JsrRecord for a given (entry, return) pair, if such a record
2186 // does not already exist.
2187 ciTypeFlow::JsrRecord* ciTypeFlow::make_jsr_record(int entry_address,
2188 int return_address) {
2189 if (_jsr_records == nullptr) {
2190 _jsr_records = new (arena()) GrowableArray<JsrRecord*>(arena(),
2191 2,
2192 0,
2193 nullptr);
2194 }
2195 JsrRecord* record = nullptr;
2196 int len = _jsr_records->length();
2197 for (int i = 0; i < len; i++) {
2198 JsrRecord* record = _jsr_records->at(i);
2199 if (record->entry_address() == entry_address &&
2200 record->return_address() == return_address) {
2201 return record;
2202 }
2203 }
2204
2205 record = new (arena()) JsrRecord(entry_address, return_address);
2206 _jsr_records->append(record);
2207 return record;
2208 }
2209
2210 // ------------------------------------------------------------------
2211 // ciTypeFlow::flow_exceptions
2212 //
2213 // Merge the current state into all exceptional successors at the
2214 // current point in the code.
2215 void ciTypeFlow::flow_exceptions(GrowableArray<ciTypeFlow::Block*>* exceptions,
2216 GrowableArray<ciInstanceKlass*>* exc_klasses,
2217 ciTypeFlow::StateVector* state) {
2218 int len = exceptions->length();
2219 assert(exc_klasses->length() == len, "must have same length");
2220 for (int i = 0; i < len; i++) {
2221 Block* block = exceptions->at(i);
2222 ciInstanceKlass* exception_klass = exc_klasses->at(i);
2223
2224 if (!exception_klass->is_loaded()) {
2225 // Do not compile any code for unloaded exception types.
2226 // Following compiler passes are responsible for doing this also.
2227 continue;
2228 }
2229
2230 if (block->meet_exception(exception_klass, state)) {
2231 // Block was modified and has PO. Add it to the work list.
2232 if (block->has_post_order() &&
2233 !block->is_on_work_list()) {
2234 add_to_work_list(block);
2235 }
2236 }
2237 }
2238 }
2239
2240 // ------------------------------------------------------------------
2241 // ciTypeFlow::flow_successors
2242 //
2243 // Merge the current state into all successors at the current point
2244 // in the code.
2245 void ciTypeFlow::flow_successors(GrowableArray<ciTypeFlow::Block*>* successors,
2246 ciTypeFlow::StateVector* state) {
2247 int len = successors->length();
2248 for (int i = 0; i < len; i++) {
2249 Block* block = successors->at(i);
2250 if (block->meet(state)) {
2251 // Block was modified and has PO. Add it to the work list.
2252 if (block->has_post_order() &&
2253 !block->is_on_work_list()) {
2254 add_to_work_list(block);
2255 }
2256 }
2257 }
2258 }
2259
2260 // ------------------------------------------------------------------
2261 // ciTypeFlow::can_trap
2262 //
2263 // Tells if a given instruction is able to generate an exception edge.
2264 bool ciTypeFlow::can_trap(ciBytecodeStream& str) {
2265 // Cf. GenerateOopMap::do_exception_edge.
2266 if (!Bytecodes::can_trap(str.cur_bc())) return false;
2267
2268 switch (str.cur_bc()) {
2269 // %%% FIXME: ldc of Class can generate an exception
2270 case Bytecodes::_ldc:
2271 case Bytecodes::_ldc_w:
2272 case Bytecodes::_ldc2_w:
2273 return str.is_in_error();
2274
2275 case Bytecodes::_aload_0:
2276 // These bytecodes can trap for rewriting. We need to assume that
2277 // they do not throw exceptions to make the monitor analysis work.
2278 return false;
2279
2280 case Bytecodes::_ireturn:
2281 case Bytecodes::_lreturn:
2282 case Bytecodes::_freturn:
2283 case Bytecodes::_dreturn:
2284 case Bytecodes::_areturn:
2285 case Bytecodes::_return:
2286 // We can assume the monitor stack is empty in this analysis.
2287 return false;
2288
2289 case Bytecodes::_monitorexit:
2290 // We can assume monitors are matched in this analysis.
2291 return false;
2292
2293 default:
2294 return true;
2295 }
2296 }
2297
2298 // ------------------------------------------------------------------
2299 // ciTypeFlow::clone_loop_heads
2300 //
2301 // Clone the loop heads
2302 bool ciTypeFlow::clone_loop_heads(StateVector* temp_vector, JsrSet* temp_set) {
2303 bool rslt = false;
2304 for (PreorderLoops iter(loop_tree_root()); !iter.done(); iter.next()) {
2305 Loop* lp = iter.current();
2306 Block* head = lp->head();
2307 if (lp == loop_tree_root() ||
2308 lp->is_irreducible() ||
2309 !head->is_clonable_exit(lp))
2310 continue;
2311
2312 // Avoid BoxLock merge.
2313 if (EliminateNestedLocks && head->has_monitorenter())
2314 continue;
2315
2316 // check not already cloned
2317 if (head->backedge_copy_count() != 0)
2318 continue;
2319
2320 // Don't clone head of OSR loop to get correct types in start block.
2321 if (is_osr_flow() && head->start() == start_bci())
2322 continue;
2323
2324 // check _no_ shared head below us
2325 Loop* ch;
2326 for (ch = lp->child(); ch != nullptr && ch->head() != head; ch = ch->sibling());
2327 if (ch != nullptr)
2328 continue;
2329
2330 // Clone head
2331 Block* new_head = head->looping_succ(lp);
2332 Block* clone = clone_loop_head(lp, temp_vector, temp_set);
2333 // Update lp's info
2334 clone->set_loop(lp);
2335 lp->set_head(new_head);
2336 lp->set_tail(clone);
2337 // And move original head into outer loop
2338 head->set_loop(lp->parent());
2339
2340 rslt = true;
2341 }
2342 return rslt;
2343 }
2344
2345 // ------------------------------------------------------------------
2346 // ciTypeFlow::clone_loop_head
2347 //
2348 // Clone lp's head and replace tail's successors with clone.
2349 //
2350 // |
2351 // v
2352 // head <-> body
2353 // |
2354 // v
2355 // exit
2356 //
2357 // new_head
2358 //
2359 // |
2360 // v
2361 // head ----------\
2362 // | |
2363 // | v
2364 // | clone <-> body
2365 // | |
2366 // | /--/
2367 // | |
2368 // v v
2369 // exit
2370 //
2371 ciTypeFlow::Block* ciTypeFlow::clone_loop_head(Loop* lp, StateVector* temp_vector, JsrSet* temp_set) {
2372 Block* head = lp->head();
2373 Block* tail = lp->tail();
2374 if (CITraceTypeFlow) {
2375 tty->print(">> Requesting clone of loop head "); head->print_value_on(tty);
2376 tty->print(" for predecessor "); tail->print_value_on(tty);
2377 tty->cr();
2378 }
2379 Block* clone = block_at(head->start(), head->jsrs(), create_backedge_copy);
2380 assert(clone->backedge_copy_count() == 1, "one backedge copy for all back edges");
2381
2382 assert(!clone->has_pre_order(), "just created");
2383 clone->set_next_pre_order();
2384
2385 // Accumulate profiled count for all backedges that share this loop's head
2386 int total_count = lp->profiled_count();
2387 for (Loop* lp1 = lp->parent(); lp1 != nullptr; lp1 = lp1->parent()) {
2388 for (Loop* lp2 = lp1; lp2 != nullptr; lp2 = lp2->sibling()) {
2389 if (lp2->head() == head && !lp2->tail()->is_backedge_copy()) {
2390 total_count += lp2->profiled_count();
2391 }
2392 }
2393 }
2394 // Have the most frequent ones branch to the clone instead
2395 int count = 0;
2396 int loops_with_shared_head = 0;
2397 Block* latest_tail = tail;
2398 bool done = false;
2399 for (Loop* lp1 = lp; lp1 != nullptr && !done; lp1 = lp1->parent()) {
2400 for (Loop* lp2 = lp1; lp2 != nullptr && !done; lp2 = lp2->sibling()) {
2401 if (lp2->head() == head && !lp2->tail()->is_backedge_copy()) {
2402 count += lp2->profiled_count();
2403 if (lp2->tail()->post_order() < latest_tail->post_order()) {
2404 latest_tail = lp2->tail();
2405 }
2406 loops_with_shared_head++;
2407 for (SuccIter iter(lp2->tail()); !iter.done(); iter.next()) {
2408 if (iter.succ() == head) {
2409 iter.set_succ(clone);
2410 // Update predecessor information
2411 head->predecessors()->remove(lp2->tail());
2412 clone->predecessors()->append(lp2->tail());
2413 }
2414 }
2415 flow_block(lp2->tail(), temp_vector, temp_set);
2416 if (lp2->head() == lp2->tail()) {
2417 // For self-loops, clone->head becomes clone->clone
2418 flow_block(clone, temp_vector, temp_set);
2419 for (SuccIter iter(clone); !iter.done(); iter.next()) {
2420 if (iter.succ() == lp2->head()) {
2421 iter.set_succ(clone);
2422 // Update predecessor information
2423 lp2->head()->predecessors()->remove(clone);
2424 clone->predecessors()->append(clone);
2425 break;
2426 }
2427 }
2428 }
2429 if (total_count == 0 || count > (total_count * .9)) {
2430 done = true;
2431 }
2432 }
2433 }
2434 }
2435 assert(loops_with_shared_head >= 1, "at least one new");
2436 clone->set_rpo_next(latest_tail->rpo_next());
2437 latest_tail->set_rpo_next(clone);
2438 flow_block(clone, temp_vector, temp_set);
2439
2440 return clone;
2441 }
2442
2443 // ------------------------------------------------------------------
2444 // ciTypeFlow::flow_block
2445 //
2446 // Interpret the effects of the bytecodes on the incoming state
2447 // vector of a basic block. Push the changed state to succeeding
2448 // basic blocks.
2449 void ciTypeFlow::flow_block(ciTypeFlow::Block* block,
2450 ciTypeFlow::StateVector* state,
2451 ciTypeFlow::JsrSet* jsrs) {
2452 if (CITraceTypeFlow) {
2453 tty->print("\n>> ANALYZING BLOCK : ");
2454 tty->cr();
2455 block->print_on(tty);
2456 }
2457 assert(block->has_pre_order(), "pre-order is assigned before 1st flow");
2458
2459 int start = block->start();
2460 int limit = block->limit();
2461 int control = block->control();
2462 if (control != ciBlock::fall_through_bci) {
2463 limit = control;
2464 }
2465
2466 // Grab the state from the current block.
2467 block->copy_state_into(state);
2468 state->def_locals()->clear();
2469
2470 GrowableArray<Block*>* exceptions = block->exceptions();
2471 GrowableArray<ciInstanceKlass*>* exc_klasses = block->exc_klasses();
2472 bool has_exceptions = exceptions->length() > 0;
2473
2474 bool exceptions_used = false;
2475
2476 ciBytecodeStream str(method());
2477 str.reset_to_bci(start);
2478 Bytecodes::Code code;
2479 while ((code = str.next()) != ciBytecodeStream::EOBC() &&
2480 str.cur_bci() < limit) {
2481 // Check for exceptional control flow from this point.
2482 if (has_exceptions && can_trap(str)) {
2483 flow_exceptions(exceptions, exc_klasses, state);
2484 exceptions_used = true;
2485 }
2486 // Apply the effects of the current bytecode to our state.
2487 bool res = state->apply_one_bytecode(&str);
2488
2489 // Watch for bailouts.
2490 if (failing()) return;
2491
2492 if (str.cur_bc() == Bytecodes::_monitorenter) {
2493 block->set_has_monitorenter();
2494 }
2495
2496 if (res) {
2497
2498 // We have encountered a trap. Record it in this block.
2499 block->set_trap(state->trap_bci(), state->trap_index());
2500
2501 if (CITraceTypeFlow) {
2502 tty->print_cr(">> Found trap");
2503 block->print_on(tty);
2504 }
2505
2506 // Save set of locals defined in this block
2507 block->def_locals()->add(state->def_locals());
2508
2509 // Record (no) successors.
2510 block->successors(&str, state, jsrs);
2511
2512 assert(!has_exceptions || exceptions_used, "Not removing exceptions");
2513
2514 // Discontinue interpretation of this Block.
2515 return;
2516 }
2517 }
2518
2519 GrowableArray<Block*>* successors = nullptr;
2520 if (control != ciBlock::fall_through_bci) {
2521 // Check for exceptional control flow from this point.
2522 if (has_exceptions && can_trap(str)) {
2523 flow_exceptions(exceptions, exc_klasses, state);
2524 exceptions_used = true;
2525 }
2526
2527 // Fix the JsrSet to reflect effect of the bytecode.
2528 block->copy_jsrs_into(jsrs);
2529 jsrs->apply_control(this, &str, state);
2530
2531 // Find successor edges based on old state and new JsrSet.
2532 successors = block->successors(&str, state, jsrs);
2533
2534 // Apply the control changes to the state.
2535 state->apply_one_bytecode(&str);
2536 } else {
2537 // Fall through control
2538 successors = block->successors(&str, nullptr, nullptr);
2539 }
2540
2541 // Save set of locals defined in this block
2542 block->def_locals()->add(state->def_locals());
2543
2544 // Remove untaken exception paths
2545 if (!exceptions_used)
2546 exceptions->clear();
2547
2548 // Pass our state to successors.
2549 flow_successors(successors, state);
2550 }
2551
2552 // ------------------------------------------------------------------
2553 // ciTypeFlow::PreOrderLoops::next
2554 //
2555 // Advance to next loop tree using a preorder, left-to-right traversal.
2556 void ciTypeFlow::PreorderLoops::next() {
2557 assert(!done(), "must not be done.");
2558 if (_current->child() != nullptr) {
2559 _current = _current->child();
2560 } else if (_current->sibling() != nullptr) {
2561 _current = _current->sibling();
2562 } else {
2563 while (_current != _root && _current->sibling() == nullptr) {
2564 _current = _current->parent();
2565 }
2566 if (_current == _root) {
2567 _current = nullptr;
2568 assert(done(), "must be done.");
2569 } else {
2570 assert(_current->sibling() != nullptr, "must be more to do");
2571 _current = _current->sibling();
2572 }
2573 }
2574 }
2575
2576 // If the tail is a branch to the head, retrieve how many times that path was taken from profiling
2577 int ciTypeFlow::Loop::profiled_count() {
2578 if (_profiled_count >= 0) {
2579 return _profiled_count;
2580 }
2581 ciMethodData* methodData = outer()->method()->method_data();
2582 if (!methodData->is_mature()) {
2583 _profiled_count = 0;
2584 return 0;
2585 }
2586 ciTypeFlow::Block* tail = this->tail();
2587 if (tail->control() == -1 || tail->has_trap()) {
2588 _profiled_count = 0;
2589 return 0;
2590 }
2591
2592 ciProfileData* data = methodData->bci_to_data(tail->control());
2593
2594 if (data == nullptr || !data->is_JumpData()) {
2595 _profiled_count = 0;
2596 return 0;
2597 }
2598
2599 ciBytecodeStream iter(outer()->method());
2600 iter.reset_to_bci(tail->control());
2601
2602 bool is_an_if = false;
2603 bool wide = false;
2604 Bytecodes::Code bc = iter.next();
2605 switch (bc) {
2606 case Bytecodes::_ifeq:
2607 case Bytecodes::_ifne:
2608 case Bytecodes::_iflt:
2609 case Bytecodes::_ifge:
2610 case Bytecodes::_ifgt:
2611 case Bytecodes::_ifle:
2612 case Bytecodes::_if_icmpeq:
2613 case Bytecodes::_if_icmpne:
2614 case Bytecodes::_if_icmplt:
2615 case Bytecodes::_if_icmpge:
2616 case Bytecodes::_if_icmpgt:
2617 case Bytecodes::_if_icmple:
2618 case Bytecodes::_if_acmpeq:
2619 case Bytecodes::_if_acmpne:
2620 case Bytecodes::_ifnull:
2621 case Bytecodes::_ifnonnull:
2622 is_an_if = true;
2623 break;
2624 case Bytecodes::_goto_w:
2625 case Bytecodes::_jsr_w:
2626 wide = true;
2627 break;
2628 case Bytecodes::_goto:
2629 case Bytecodes::_jsr:
2630 break;
2631 default:
2632 fatal(" invalid bytecode: %s", Bytecodes::name(iter.cur_bc()));
2633 }
2634
2635 GrowableArray<ciTypeFlow::Block*>* succs = tail->successors();
2636
2637 if (!is_an_if) {
2638 assert(((wide ? iter.get_far_dest() : iter.get_dest()) == head()->start()) == (succs->at(ciTypeFlow::GOTO_TARGET) == head()), "branch should lead to loop head");
2639 if (succs->at(ciTypeFlow::GOTO_TARGET) == head()) {
2640 _profiled_count = outer()->method()->scale_count(data->as_JumpData()->taken());
2641 return _profiled_count;
2642 }
2643 } else {
2644 assert((iter.get_dest() == head()->start()) == (succs->at(ciTypeFlow::IF_TAKEN) == head()), "bytecode and CFG not consistent");
2645 assert((tail->limit() == head()->start()) == (succs->at(ciTypeFlow::IF_NOT_TAKEN) == head()), "bytecode and CFG not consistent");
2646 if (succs->at(ciTypeFlow::IF_TAKEN) == head()) {
2647 _profiled_count = outer()->method()->scale_count(data->as_JumpData()->taken());
2648 return _profiled_count;
2649 } else if (succs->at(ciTypeFlow::IF_NOT_TAKEN) == head()) {
2650 _profiled_count = outer()->method()->scale_count(data->as_BranchData()->not_taken());
2651 return _profiled_count;
2652 }
2653 }
2654
2655 _profiled_count = 0;
2656 return _profiled_count;
2657 }
2658
2659 bool ciTypeFlow::Loop::at_insertion_point(Loop* lp, Loop* current) {
2660 int lp_pre_order = lp->head()->pre_order();
2661 if (current->head()->pre_order() < lp_pre_order) {
2662 return true;
2663 } else if (current->head()->pre_order() > lp_pre_order) {
2664 return false;
2665 }
2666 // In the case of a shared head, make the most frequent head/tail (as reported by profiling) the inner loop
2667 if (current->head() == lp->head()) {
2668 int lp_count = lp->profiled_count();
2669 int current_count = current->profiled_count();
2670 if (current_count < lp_count) {
2671 return true;
2672 } else if (current_count > lp_count) {
2673 return false;
2674 }
2675 }
2676 if (current->tail()->pre_order() > lp->tail()->pre_order()) {
2677 return true;
2678 }
2679 return false;
2680 }
2681
2682 // ------------------------------------------------------------------
2683 // ciTypeFlow::Loop::sorted_merge
2684 //
2685 // Merge the branch lp into this branch, sorting on the loop head
2686 // pre_orders. Returns the leaf of the merged branch.
2687 // Child and sibling pointers will be setup later.
2688 // Sort is (looking from leaf towards the root)
2689 // descending on primary key: loop head's pre_order, and
2690 // ascending on secondary key: loop tail's pre_order.
2691 ciTypeFlow::Loop* ciTypeFlow::Loop::sorted_merge(Loop* lp) {
2692 Loop* leaf = this;
2693 Loop* prev = nullptr;
2694 Loop* current = leaf;
2695 while (lp != nullptr) {
2696 int lp_pre_order = lp->head()->pre_order();
2697 // Find insertion point for "lp"
2698 while (current != nullptr) {
2699 if (current == lp) {
2700 return leaf; // Already in list
2701 }
2702 if (at_insertion_point(lp, current)) {
2703 break;
2704 }
2705 prev = current;
2706 current = current->parent();
2707 }
2708 Loop* next_lp = lp->parent(); // Save future list of items to insert
2709 // Insert lp before current
2710 lp->set_parent(current);
2711 if (prev != nullptr) {
2712 prev->set_parent(lp);
2713 } else {
2714 leaf = lp;
2715 }
2716 prev = lp; // Inserted item is new prev[ious]
2717 lp = next_lp; // Next item to insert
2718 }
2719 return leaf;
2720 }
2721
2722 // ------------------------------------------------------------------
2723 // ciTypeFlow::build_loop_tree
2724 //
2725 // Incrementally build loop tree.
2726 void ciTypeFlow::build_loop_tree(Block* blk) {
2727 assert(!blk->is_post_visited(), "precondition");
2728 Loop* innermost = nullptr; // merge of loop tree branches over all successors
2729
2730 for (SuccIter iter(blk); !iter.done(); iter.next()) {
2731 Loop* lp = nullptr;
2732 Block* succ = iter.succ();
2733 if (!succ->is_post_visited()) {
2734 // Found backedge since predecessor post visited, but successor is not
2735 assert(succ->pre_order() <= blk->pre_order(), "should be backedge");
2736
2737 // Create a LoopNode to mark this loop.
2738 lp = new (arena()) Loop(succ, blk);
2739 if (succ->loop() == nullptr)
2740 succ->set_loop(lp);
2741 // succ->loop will be updated to innermost loop on a later call, when blk==succ
2742
2743 } else { // Nested loop
2744 lp = succ->loop();
2745
2746 // If succ is loop head, find outer loop.
2747 while (lp != nullptr && lp->head() == succ) {
2748 lp = lp->parent();
2749 }
2750 if (lp == nullptr) {
2751 // Infinite loop, it's parent is the root
2752 lp = loop_tree_root();
2753 }
2754 }
2755
2756 // Check for irreducible loop.
2757 // Successor has already been visited. If the successor's loop head
2758 // has already been post-visited, then this is another entry into the loop.
2759 while (lp->head()->is_post_visited() && lp != loop_tree_root()) {
2760 _has_irreducible_entry = true;
2761 lp->set_irreducible(succ);
2762 if (!succ->is_on_work_list()) {
2763 // Assume irreducible entries need more data flow
2764 add_to_work_list(succ);
2765 }
2766 Loop* plp = lp->parent();
2767 if (plp == nullptr) {
2768 // This only happens for some irreducible cases. The parent
2769 // will be updated during a later pass.
2770 break;
2771 }
2772 lp = plp;
2773 }
2774
2775 // Merge loop tree branch for all successors.
2776 innermost = innermost == nullptr ? lp : innermost->sorted_merge(lp);
2777
2778 } // end loop
2779
2780 if (innermost == nullptr) {
2781 assert(blk->successors()->length() == 0, "CFG exit");
2782 blk->set_loop(loop_tree_root());
2783 } else if (innermost->head() == blk) {
2784 // If loop header, complete the tree pointers
2785 if (blk->loop() != innermost) {
2786 #ifdef ASSERT
2787 assert(blk->loop()->head() == innermost->head(), "same head");
2788 Loop* dl;
2789 for (dl = innermost; dl != nullptr && dl != blk->loop(); dl = dl->parent());
2790 assert(dl == blk->loop(), "blk->loop() already in innermost list");
2791 #endif
2792 blk->set_loop(innermost);
2793 }
2794 innermost->def_locals()->add(blk->def_locals());
2795 Loop* l = innermost;
2796 Loop* p = l->parent();
2797 while (p && l->head() == blk) {
2798 l->set_sibling(p->child()); // Put self on parents 'next child'
2799 p->set_child(l); // Make self the first child of parent
2800 p->def_locals()->add(l->def_locals());
2801 l = p; // Walk up the parent chain
2802 p = l->parent();
2803 }
2804 } else {
2805 blk->set_loop(innermost);
2806 innermost->def_locals()->add(blk->def_locals());
2807 }
2808 }
2809
2810 // ------------------------------------------------------------------
2811 // ciTypeFlow::Loop::contains
2812 //
2813 // Returns true if lp is nested loop.
2814 bool ciTypeFlow::Loop::contains(ciTypeFlow::Loop* lp) const {
2815 assert(lp != nullptr, "");
2816 if (this == lp || head() == lp->head()) return true;
2817 int depth1 = depth();
2818 int depth2 = lp->depth();
2819 if (depth1 > depth2)
2820 return false;
2821 while (depth1 < depth2) {
2822 depth2--;
2823 lp = lp->parent();
2824 }
2825 return this == lp;
2826 }
2827
2828 // ------------------------------------------------------------------
2829 // ciTypeFlow::Loop::depth
2830 //
2831 // Loop depth
2832 int ciTypeFlow::Loop::depth() const {
2833 int dp = 0;
2834 for (Loop* lp = this->parent(); lp != nullptr; lp = lp->parent())
2835 dp++;
2836 return dp;
2837 }
2838
2839 #ifndef PRODUCT
2840 // ------------------------------------------------------------------
2841 // ciTypeFlow::Loop::print
2842 void ciTypeFlow::Loop::print(outputStream* st, int indent) const {
2843 for (int i = 0; i < indent; i++) st->print(" ");
2844 st->print("%d<-%d %s",
2845 is_root() ? 0 : this->head()->pre_order(),
2846 is_root() ? 0 : this->tail()->pre_order(),
2847 is_irreducible()?" irr":"");
2848 st->print(" defs: ");
2849 def_locals()->print_on(st, _head->outer()->method()->max_locals());
2850 st->cr();
2851 for (Loop* ch = child(); ch != nullptr; ch = ch->sibling())
2852 ch->print(st, indent+2);
2853 }
2854 #endif
2855
2856 // ------------------------------------------------------------------
2857 // ciTypeFlow::df_flow_types
2858 //
2859 // Perform the depth first type flow analysis. Helper for flow_types.
2860 void ciTypeFlow::df_flow_types(Block* start,
2861 bool do_flow,
2862 StateVector* temp_vector,
2863 JsrSet* temp_set) {
2864 int dft_len = 100;
2865 GrowableArray<Block*> stk(dft_len);
2866
2867 ciBlock* dummy = _method->get_method_blocks()->make_dummy_block();
2868 JsrSet* root_set = new JsrSet(0);
2869 Block* root_head = new (arena()) Block(this, dummy, root_set);
2870 Block* root_tail = new (arena()) Block(this, dummy, root_set);
2871 root_head->set_pre_order(0);
2872 root_head->set_post_order(0);
2873 root_tail->set_pre_order(max_jint);
2874 root_tail->set_post_order(max_jint);
2875 set_loop_tree_root(new (arena()) Loop(root_head, root_tail));
2876
2877 stk.push(start);
2878
2879 _next_pre_order = 0; // initialize pre_order counter
2880 _rpo_list = nullptr;
2881 int next_po = 0; // initialize post_order counter
2882
2883 // Compute RPO and the control flow graph
2884 int size;
2885 while ((size = stk.length()) > 0) {
2886 Block* blk = stk.top(); // Leave node on stack
2887 if (!blk->is_visited()) {
2888 // forward arc in graph
2889 assert (!blk->has_pre_order(), "");
2890 blk->set_next_pre_order();
2891
2892 if (_next_pre_order >= (int)Compile::current()->max_node_limit() / 2) {
2893 // Too many basic blocks. Bail out.
2894 // This can happen when try/finally constructs are nested to depth N,
2895 // and there is O(2**N) cloning of jsr bodies. See bug 4697245!
2896 // "MaxNodeLimit / 2" is used because probably the parser will
2897 // generate at least twice that many nodes and bail out.
2898 record_failure("too many basic blocks");
2899 return;
2900 }
2901 if (do_flow) {
2902 flow_block(blk, temp_vector, temp_set);
2903 if (failing()) return; // Watch for bailouts.
2904 }
2905 } else if (!blk->is_post_visited()) {
2906 // cross or back arc
2907 for (SuccIter iter(blk); !iter.done(); iter.next()) {
2908 Block* succ = iter.succ();
2909 if (!succ->is_visited()) {
2910 stk.push(succ);
2911 }
2912 }
2913 if (stk.length() == size) {
2914 // There were no additional children, post visit node now
2915 stk.pop(); // Remove node from stack
2916
2917 build_loop_tree(blk);
2918 blk->set_post_order(next_po++); // Assign post order
2919 prepend_to_rpo_list(blk);
2920 assert(blk->is_post_visited(), "");
2921
2922 if (blk->is_loop_head() && !blk->is_on_work_list()) {
2923 // Assume loop heads need more data flow
2924 add_to_work_list(blk);
2925 }
2926 }
2927 } else {
2928 stk.pop(); // Remove post-visited node from stack
2929 }
2930 }
2931 }
2932
2933 // ------------------------------------------------------------------
2934 // ciTypeFlow::flow_types
2935 //
2936 // Perform the type flow analysis, creating and cloning Blocks as
2937 // necessary.
2938 void ciTypeFlow::flow_types() {
2939 ResourceMark rm;
2940 StateVector* temp_vector = new StateVector(this);
2941 JsrSet* temp_set = new JsrSet(4);
2942
2943 // Create the method entry block.
2944 Block* start = block_at(start_bci(), temp_set);
2945
2946 // Load the initial state into it.
2947 const StateVector* start_state = get_start_state();
2948 if (failing()) return;
2949 start->meet(start_state);
2950
2951 // Depth first visit
2952 df_flow_types(start, true /*do flow*/, temp_vector, temp_set);
2953
2954 if (failing()) return;
2955 assert(_rpo_list == start, "must be start");
2956
2957 // Any loops found?
2958 if (loop_tree_root()->child() != nullptr &&
2959 env()->comp_level() >= CompLevel_full_optimization) {
2960 // Loop optimizations are not performed on Tier1 compiles.
2961
2962 bool changed = clone_loop_heads(temp_vector, temp_set);
2963
2964 // If some loop heads were cloned, recompute postorder and loop tree
2965 if (changed) {
2966 loop_tree_root()->set_child(nullptr);
2967 for (Block* blk = _rpo_list; blk != nullptr;) {
2968 Block* next = blk->rpo_next();
2969 blk->df_init();
2970 blk = next;
2971 }
2972 df_flow_types(start, false /*no flow*/, temp_vector, temp_set);
2973 }
2974 }
2975
2976 if (CITraceTypeFlow) {
2977 tty->print_cr("\nLoop tree");
2978 loop_tree_root()->print();
2979 }
2980
2981 // Continue flow analysis until fixed point reached
2982
2983 debug_only(int max_block = _next_pre_order;)
2984
2985 while (!work_list_empty()) {
2986 Block* blk = work_list_next();
2987 assert (blk->has_post_order(), "post order assigned above");
2988
2989 flow_block(blk, temp_vector, temp_set);
2990
2991 assert (max_block == _next_pre_order, "no new blocks");
2992 assert (!failing(), "no more bailouts");
2993 }
2994 }
2995
2996 // ------------------------------------------------------------------
2997 // ciTypeFlow::map_blocks
2998 //
2999 // Create the block map, which indexes blocks in reverse post-order.
3000 void ciTypeFlow::map_blocks() {
3001 assert(_block_map == nullptr, "single initialization");
3002 int block_ct = _next_pre_order;
3003 _block_map = NEW_ARENA_ARRAY(arena(), Block*, block_ct);
3004 assert(block_ct == block_count(), "");
3005
3006 Block* blk = _rpo_list;
3007 for (int m = 0; m < block_ct; m++) {
3008 int rpo = blk->rpo();
3009 assert(rpo == m, "should be sequential");
3010 _block_map[rpo] = blk;
3011 blk = blk->rpo_next();
3012 }
3013 assert(blk == nullptr, "should be done");
3014
3015 for (int j = 0; j < block_ct; j++) {
3016 assert(_block_map[j] != nullptr, "must not drop any blocks");
3017 Block* block = _block_map[j];
3018 // Remove dead blocks from successor lists:
3019 for (int e = 0; e <= 1; e++) {
3020 GrowableArray<Block*>* l = e? block->exceptions(): block->successors();
3021 for (int k = 0; k < l->length(); k++) {
3022 Block* s = l->at(k);
3023 if (!s->has_post_order()) {
3024 if (CITraceTypeFlow) {
3025 tty->print("Removing dead %s successor of #%d: ", (e? "exceptional": "normal"), block->pre_order());
3026 s->print_value_on(tty);
3027 tty->cr();
3028 }
3029 l->remove(s);
3030 --k;
3031 }
3032 }
3033 }
3034 }
3035 }
3036
3037 // ------------------------------------------------------------------
3038 // ciTypeFlow::get_block_for
3039 //
3040 // Find a block with this ciBlock which has a compatible JsrSet.
3041 // If no such block exists, create it, unless the option is no_create.
3042 // If the option is create_backedge_copy, always create a fresh backedge copy.
3043 ciTypeFlow::Block* ciTypeFlow::get_block_for(int ciBlockIndex, ciTypeFlow::JsrSet* jsrs, CreateOption option) {
3044 Arena* a = arena();
3045 GrowableArray<Block*>* blocks = _idx_to_blocklist[ciBlockIndex];
3046 if (blocks == nullptr) {
3047 // Query only?
3048 if (option == no_create) return nullptr;
3049
3050 // Allocate the growable array.
3051 blocks = new (a) GrowableArray<Block*>(a, 4, 0, nullptr);
3052 _idx_to_blocklist[ciBlockIndex] = blocks;
3053 }
3054
3055 if (option != create_backedge_copy) {
3056 int len = blocks->length();
3057 for (int i = 0; i < len; i++) {
3058 Block* block = blocks->at(i);
3059 if (!block->is_backedge_copy() && block->is_compatible_with(jsrs)) {
3060 return block;
3061 }
3062 }
3063 }
3064
3065 // Query only?
3066 if (option == no_create) return nullptr;
3067
3068 // We did not find a compatible block. Create one.
3069 Block* new_block = new (a) Block(this, _method->get_method_blocks()->block(ciBlockIndex), jsrs);
3070 if (option == create_backedge_copy) new_block->set_backedge_copy(true);
3071 blocks->append(new_block);
3072 return new_block;
3073 }
3074
3075 // ------------------------------------------------------------------
3076 // ciTypeFlow::backedge_copy_count
3077 //
3078 int ciTypeFlow::backedge_copy_count(int ciBlockIndex, ciTypeFlow::JsrSet* jsrs) const {
3079 GrowableArray<Block*>* blocks = _idx_to_blocklist[ciBlockIndex];
3080
3081 if (blocks == nullptr) {
3082 return 0;
3083 }
3084
3085 int count = 0;
3086 int len = blocks->length();
3087 for (int i = 0; i < len; i++) {
3088 Block* block = blocks->at(i);
3089 if (block->is_backedge_copy() && block->is_compatible_with(jsrs)) {
3090 count++;
3091 }
3092 }
3093
3094 return count;
3095 }
3096
3097 // ------------------------------------------------------------------
3098 // ciTypeFlow::do_flow
3099 //
3100 // Perform type inference flow analysis.
3101 void ciTypeFlow::do_flow() {
3102 if (CITraceTypeFlow) {
3103 tty->print_cr("\nPerforming flow analysis on method");
3104 method()->print();
3105 if (is_osr_flow()) tty->print(" at OSR bci %d", start_bci());
3106 tty->cr();
3107 method()->print_codes();
3108 }
3109 if (CITraceTypeFlow) {
3110 tty->print_cr("Initial CI Blocks");
3111 print_on(tty);
3112 }
3113 flow_types();
3114 // Watch for bailouts.
3115 if (failing()) {
3116 return;
3117 }
3118
3119 map_blocks();
3120
3121 if (CIPrintTypeFlow || CITraceTypeFlow) {
3122 rpo_print_on(tty);
3123 }
3124 }
3125
3126 // ------------------------------------------------------------------
3127 // ciTypeFlow::is_dominated_by
3128 //
3129 // Determine if the instruction at bci is dominated by the instruction at dom_bci.
3130 bool ciTypeFlow::is_dominated_by(int bci, int dom_bci) {
3131 assert(!method()->has_jsrs(), "jsrs are not supported");
3132
3133 ResourceMark rm;
3134 JsrSet* jsrs = new ciTypeFlow::JsrSet();
3135 int index = _method->get_method_blocks()->block_containing(bci)->index();
3136 int dom_index = _method->get_method_blocks()->block_containing(dom_bci)->index();
3137 Block* block = get_block_for(index, jsrs, ciTypeFlow::no_create);
3138 Block* dom_block = get_block_for(dom_index, jsrs, ciTypeFlow::no_create);
3139
3140 // Start block dominates all other blocks
3141 if (start_block()->rpo() == dom_block->rpo()) {
3142 return true;
3143 }
3144
3145 // Dominated[i] is true if block i is dominated by dom_block
3146 int num_blocks = block_count();
3147 bool* dominated = NEW_RESOURCE_ARRAY(bool, num_blocks);
3148 for (int i = 0; i < num_blocks; ++i) {
3149 dominated[i] = true;
3150 }
3151 dominated[start_block()->rpo()] = false;
3152
3153 // Iterative dominator algorithm
3154 bool changed = true;
3155 while (changed) {
3156 changed = false;
3157 // Use reverse postorder iteration
3158 for (Block* blk = _rpo_list; blk != nullptr; blk = blk->rpo_next()) {
3159 if (blk->is_start()) {
3160 // Ignore start block
3161 continue;
3162 }
3163 // The block is dominated if it is the dominating block
3164 // itself or if all predecessors are dominated.
3165 int index = blk->rpo();
3166 bool dom = (index == dom_block->rpo());
3167 if (!dom) {
3168 // Check if all predecessors are dominated
3169 dom = true;
3170 for (int i = 0; i < blk->predecessors()->length(); ++i) {
3171 Block* pred = blk->predecessors()->at(i);
3172 if (!dominated[pred->rpo()]) {
3173 dom = false;
3174 break;
3175 }
3176 }
3177 }
3178 // Update dominator information
3179 if (dominated[index] != dom) {
3180 changed = true;
3181 dominated[index] = dom;
3182 }
3183 }
3184 }
3185 // block dominated by dom_block?
3186 return dominated[block->rpo()];
3187 }
3188
3189 // ------------------------------------------------------------------
3190 // ciTypeFlow::record_failure()
3191 // The ciTypeFlow object keeps track of failure reasons separately from the ciEnv.
3192 // This is required because there is not a 1-1 relation between the ciEnv and
3193 // the TypeFlow passes within a compilation task. For example, if the compiler
3194 // is considering inlining a method, it will request a TypeFlow. If that fails,
3195 // the compilation as a whole may continue without the inlining. Some TypeFlow
3196 // requests are not optional; if they fail the requestor is responsible for
3197 // copying the failure reason up to the ciEnv. (See Parse::Parse.)
3198 void ciTypeFlow::record_failure(const char* reason) {
3199 if (env()->log() != nullptr) {
3200 env()->log()->elem("failure reason='%s' phase='typeflow'", reason);
3201 }
3202 if (_failure_reason == nullptr) {
3203 // Record the first failure reason.
3204 _failure_reason = reason;
3205 }
3206 }
3207
3208 ciType* ciTypeFlow::mark_as_null_free(ciType* type) {
3209 // Wrap the type to carry the information that it is null-free
3210 return env()->make_null_free_wrapper(type);
3211 }
3212
3213 #ifndef PRODUCT
3214 void ciTypeFlow::print() const { print_on(tty); }
3215
3216 // ------------------------------------------------------------------
3217 // ciTypeFlow::print_on
3218 void ciTypeFlow::print_on(outputStream* st) const {
3219 // Walk through CI blocks
3220 st->print_cr("********************************************************");
3221 st->print ("TypeFlow for ");
3222 method()->name()->print_symbol_on(st);
3223 int limit_bci = code_size();
3224 st->print_cr(" %d bytes", limit_bci);
3225 ciMethodBlocks* mblks = _method->get_method_blocks();
3226 ciBlock* current = nullptr;
3227 for (int bci = 0; bci < limit_bci; bci++) {
3228 ciBlock* blk = mblks->block_containing(bci);
3229 if (blk != nullptr && blk != current) {
3230 current = blk;
3231 current->print_on(st);
3232
3233 GrowableArray<Block*>* blocks = _idx_to_blocklist[blk->index()];
3234 int num_blocks = (blocks == nullptr) ? 0 : blocks->length();
3235
3236 if (num_blocks == 0) {
3237 st->print_cr(" No Blocks");
3238 } else {
3239 for (int i = 0; i < num_blocks; i++) {
3240 Block* block = blocks->at(i);
3241 block->print_on(st);
3242 }
3243 }
3244 st->print_cr("--------------------------------------------------------");
3245 st->cr();
3246 }
3247 }
3248 st->print_cr("********************************************************");
3249 st->cr();
3250 }
3251
3252 void ciTypeFlow::rpo_print_on(outputStream* st) const {
3253 st->print_cr("********************************************************");
3254 st->print ("TypeFlow for ");
3255 method()->name()->print_symbol_on(st);
3256 int limit_bci = code_size();
3257 st->print_cr(" %d bytes", limit_bci);
3258 for (Block* blk = _rpo_list; blk != nullptr; blk = blk->rpo_next()) {
3259 blk->print_on(st);
3260 st->print_cr("--------------------------------------------------------");
3261 st->cr();
3262 }
3263 st->print_cr("********************************************************");
3264 st->cr();
3265 }
3266 #endif