1 /*
2 * Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "ci/ciConstant.hpp"
27 #include "ci/ciField.hpp"
28 #include "ci/ciMethod.hpp"
29 #include "ci/ciMethodData.hpp"
30 #include "ci/ciObjArrayKlass.hpp"
31 #include "ci/ciStreams.hpp"
32 #include "ci/ciTypeArrayKlass.hpp"
33 #include "ci/ciTypeFlow.hpp"
34 #include "ci/ciValueKlass.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 ciTypeFlow::JsrSet::JsrSet(Arena* arena, int default_len) {
60 if (arena != NULL) {
61 // Allocate growable array in Arena.
62 _set = new (arena) GrowableArray<JsrRecord*>(arena, default_len, 0, NULL);
63 } else {
64 // Allocate growable array in current ResourceArea.
65 _set = new GrowableArray<JsrRecord*>(4, 0, NULL, false);
66 }
67 }
68
69 // ------------------------------------------------------------------
70 // ciTypeFlow::JsrSet::copy_into
71 void ciTypeFlow::JsrSet::copy_into(JsrSet* jsrs) {
72 int len = size();
73 jsrs->_set->clear();
74 for (int i = 0; i < len; i++) {
75 jsrs->_set->append(_set->at(i));
76 }
77 }
78
79 // ------------------------------------------------------------------
80 // ciTypeFlow::JsrSet::is_compatible_with
81 //
82 // !!!! MISGIVINGS ABOUT THIS... disregard
83 //
84 // Is this JsrSet compatible with some other JsrSet?
85 //
86 // In set-theoretic terms, a JsrSet can be viewed as a partial function
87 // from entry addresses to return addresses. Two JsrSets A and B are
88 // compatible iff
89 //
90 // For any x,
91 // A(x) defined and B(x) defined implies A(x) == B(x)
92 //
93 // Less formally, two JsrSets are compatible when they have identical
94 // return addresses for any entry addresses they share in common.
95 bool ciTypeFlow::JsrSet::is_compatible_with(JsrSet* other) {
96 // Walk through both sets in parallel. If the same entry address
97 // appears in both sets, then the return address must match for
98 // the sets to be compatible.
99 int size1 = size();
100 int size2 = other->size();
101
102 // Special case. If nothing is on the jsr stack, then there can
103 // be no ret.
104 if (size2 == 0) {
105 return true;
106 } else if (size1 != size2) {
107 return false;
108 } else {
109 for (int i = 0; i < size1; i++) {
110 JsrRecord* record1 = record_at(i);
111 JsrRecord* record2 = other->record_at(i);
112 if (record1->entry_address() != record2->entry_address() ||
113 record1->return_address() != record2->return_address()) {
114 return false;
115 }
116 }
117 return true;
118 }
119
120 #if 0
121 int pos1 = 0;
122 int pos2 = 0;
123 int size1 = size();
124 int size2 = other->size();
125 while (pos1 < size1 && pos2 < size2) {
126 JsrRecord* record1 = record_at(pos1);
127 JsrRecord* record2 = other->record_at(pos2);
128 int entry1 = record1->entry_address();
129 int entry2 = record2->entry_address();
130 if (entry1 < entry2) {
131 pos1++;
132 } else if (entry1 > entry2) {
133 pos2++;
134 } else {
135 if (record1->return_address() == record2->return_address()) {
136 pos1++;
137 pos2++;
138 } else {
139 // These two JsrSets are incompatible.
140 return false;
141 }
142 }
143 }
144 // The two JsrSets agree.
145 return true;
146 #endif
147 }
148
149 // ------------------------------------------------------------------
150 // ciTypeFlow::JsrSet::insert_jsr_record
151 //
152 // Insert the given JsrRecord into the JsrSet, maintaining the order
153 // of the set and replacing any element with the same entry address.
154 void ciTypeFlow::JsrSet::insert_jsr_record(JsrRecord* record) {
155 int len = size();
156 int entry = record->entry_address();
157 int pos = 0;
158 for ( ; pos < len; pos++) {
159 JsrRecord* current = record_at(pos);
160 if (entry == current->entry_address()) {
161 // Stomp over this entry.
162 _set->at_put(pos, record);
163 assert(size() == len, "must be same size");
164 return;
165 } else if (entry < current->entry_address()) {
166 break;
167 }
168 }
169
170 // Insert the record into the list.
171 JsrRecord* swap = record;
172 JsrRecord* temp = NULL;
173 for ( ; pos < len; pos++) {
174 temp = _set->at(pos);
175 _set->at_put(pos, swap);
176 swap = temp;
177 }
178 _set->append(swap);
179 assert(size() == len+1, "must be larger");
180 }
181
182 // ------------------------------------------------------------------
183 // ciTypeFlow::JsrSet::remove_jsr_record
184 //
185 // Remove the JsrRecord with the given return address from the JsrSet.
186 void ciTypeFlow::JsrSet::remove_jsr_record(int return_address) {
187 int len = size();
188 for (int i = 0; i < len; i++) {
189 if (record_at(i)->return_address() == return_address) {
190 // We have found the proper entry. Remove it from the
191 // JsrSet and exit.
192 for (int j = i+1; j < len ; j++) {
193 _set->at_put(j-1, _set->at(j));
194 }
195 _set->trunc_to(len-1);
196 assert(size() == len-1, "must be smaller");
197 return;
198 }
199 }
200 assert(false, "verify: returning from invalid subroutine");
201 }
202
203 // ------------------------------------------------------------------
204 // ciTypeFlow::JsrSet::apply_control
205 //
206 // Apply the effect of a control-flow bytecode on the JsrSet. The
207 // only bytecodes that modify the JsrSet are jsr and ret.
208 void ciTypeFlow::JsrSet::apply_control(ciTypeFlow* analyzer,
209 ciBytecodeStream* str,
210 ciTypeFlow::StateVector* state) {
211 Bytecodes::Code code = str->cur_bc();
212 if (code == Bytecodes::_jsr) {
213 JsrRecord* record =
214 analyzer->make_jsr_record(str->get_dest(), str->next_bci());
215 insert_jsr_record(record);
216 } else if (code == Bytecodes::_jsr_w) {
217 JsrRecord* record =
218 analyzer->make_jsr_record(str->get_far_dest(), str->next_bci());
219 insert_jsr_record(record);
220 } else if (code == Bytecodes::_ret) {
221 Cell local = state->local(str->get_index());
222 ciType* return_address = state->type_at(local);
223 assert(return_address->is_return_address(), "verify: wrong type");
224 if (size() == 0) {
225 // Ret-state underflow: Hit a ret w/o any previous jsrs. Bail out.
226 // This can happen when a loop is inside a finally clause (4614060).
227 analyzer->record_failure("OSR in finally clause");
228 return;
229 }
230 remove_jsr_record(return_address->as_return_address()->bci());
231 }
232 }
233
234 #ifndef PRODUCT
235 // ------------------------------------------------------------------
236 // ciTypeFlow::JsrSet::print_on
237 void ciTypeFlow::JsrSet::print_on(outputStream* st) const {
238 st->print("{ ");
239 int num_elements = size();
240 if (num_elements > 0) {
241 int i = 0;
242 for( ; i < num_elements - 1; i++) {
243 _set->at(i)->print_on(st);
244 st->print(", ");
245 }
246 _set->at(i)->print_on(st);
247 st->print(" ");
248 }
249 st->print("}");
250 }
251 #endif
252
253 // ciTypeFlow::StateVector
254 //
255 // A StateVector summarizes the type information at some point in
256 // the program.
257
258 // ------------------------------------------------------------------
259 // ciTypeFlow::StateVector::type_meet
260 //
261 // Meet two types.
262 //
263 // The semi-lattice of types use by this analysis are modeled on those
264 // of the verifier. The lattice is as follows:
265 //
266 // top_type() >= all non-extremal types >= bottom_type
267 // and
268 // Every primitive type is comparable only with itself. The meet of
269 // reference types is determined by their kind: instance class,
270 // interface, or array class. The meet of two types of the same
271 // kind is their least common ancestor. The meet of two types of
272 // different kinds is always java.lang.Object.
273 ciType* ciTypeFlow::StateVector::type_meet_internal(ciType* t1, ciType* t2, ciTypeFlow* analyzer) {
274 assert(t1 != t2, "checked in caller");
275 if (t1->equals(top_type())) {
276 return t2;
277 } else if (t2->equals(top_type())) {
278 return t1;
279 }
280
281 // Unwrap after saving nullness information and handling top meets
282 bool never_null1 = t1->is_never_null();
283 bool never_null2 = t2->is_never_null();
284 if (t1->unwrap() == t2->unwrap() && never_null1 == never_null2) {
285 return t1;
286 }
287 t1 = t1->unwrap();
288 t2 = t2->unwrap();
289
290 if (t1->is_primitive_type() || t2->is_primitive_type()) {
291 // Special case null_type. null_type meet any reference type T
292 // is T. null_type meet null_type is null_type.
293 if (t1->equals(null_type())) {
294 if (!t2->is_primitive_type() || t2->equals(null_type())) {
295 return t2;
296 }
297 } else if (t2->equals(null_type())) {
298 if (!t1->is_primitive_type()) {
299 return t1;
300 }
301 }
302
303 // At least one of the two types is a non-top primitive type.
304 // The other type is not equal to it. Fall to bottom.
305 return bottom_type();
306 }
307
308 // Both types are non-top non-primitive types. That is,
309 // both types are either instanceKlasses or arrayKlasses.
310 ciKlass* object_klass = analyzer->env()->Object_klass();
311 ciKlass* k1 = t1->as_klass();
312 ciKlass* k2 = t2->as_klass();
313 if (k1->equals(object_klass) || k2->equals(object_klass)) {
314 return object_klass;
315 } else if (!k1->is_loaded() || !k2->is_loaded()) {
316 // Unloaded classes fall to java.lang.Object at a merge.
317 return object_klass;
318 } else if (k1->is_interface() != k2->is_interface()) {
319 // When an interface meets a non-interface, we get Object;
320 // This is what the verifier does.
321 return object_klass;
322 } else if (k1->is_array_klass() || k2->is_array_klass()) {
323 // When an array meets a non-array, we get Object.
324 // When (obj/value)Array meets typeArray, we also get Object.
325 // And when typeArray meets different typeArray, we again get Object.
326 // But when (obj/value)Array meets (obj/value)Array, we look carefully at element types and storage properties.
327 if ((k1->is_obj_array_klass() || k1->is_value_array_klass()) &&
328 (k2->is_obj_array_klass() || k2->is_value_array_klass())) {
329 bool prop_mismatch = k1->as_array_klass()->storage_properties().value() !=
330 k2->as_array_klass()->storage_properties().value();
331 bool never_null = k1->as_array_klass()->storage_properties().is_null_free() &&
332 k2->as_array_klass()->storage_properties().is_null_free();
333 ciType* elem1 = k1->as_array_klass()->element_klass();
334 ciType* elem2 = k2->as_array_klass()->element_klass();
335 ciType* elem = elem1;
336 if (elem1 != elem2) {
337 elem = type_meet_internal(elem1, elem2, analyzer)->as_klass();
338 }
339 // Do an easy shortcut if one type is a super of the other.
340 if (elem == elem1 && !prop_mismatch) {
341 assert(k1 == ciArrayKlass::make(elem, never_null), "shortcut is OK");
342 return k1;
343 } else if (elem == elem2 && !prop_mismatch) {
344 assert(k2 == ciArrayKlass::make(elem, never_null), "shortcut is OK");
345 return k2;
346 } else {
347 return ciArrayKlass::make(elem, never_null);
348 }
349 } else {
350 return object_klass;
351 }
352 } else {
353 // Must be two plain old instance klasses.
354 assert(k1->is_instance_klass(), "previous cases handle non-instances");
355 assert(k2->is_instance_klass(), "previous cases handle non-instances");
356 ciType* result = k1->least_common_ancestor(k2);
357 if (never_null1 && never_null2 && result->is_valuetype()) {
358 // Both value types are never null, mark the result as never null
359 result = analyzer->mark_as_never_null(result);
360 }
361 return result;
362 }
363 }
364
365
366 // ------------------------------------------------------------------
367 // ciTypeFlow::StateVector::StateVector
368 //
369 // Build a new state vector
370 ciTypeFlow::StateVector::StateVector(ciTypeFlow* analyzer) {
371 _outer = analyzer;
372 _stack_size = -1;
373 _monitor_count = -1;
374 // Allocate the _types array
375 int max_cells = analyzer->max_cells();
376 _types = (ciType**)analyzer->arena()->Amalloc(sizeof(ciType*) * max_cells);
377 for (int i=0; i<max_cells; i++) {
378 _types[i] = top_type();
379 }
380 _trap_bci = -1;
381 _trap_index = 0;
382 _def_locals.clear();
383 }
384
385
386 // ------------------------------------------------------------------
387 // ciTypeFlow::get_start_state
388 //
389 // Set this vector to the method entry state.
390 const ciTypeFlow::StateVector* ciTypeFlow::get_start_state() {
391 StateVector* state = new StateVector(this);
392 if (is_osr_flow()) {
393 ciTypeFlow* non_osr_flow = method()->get_flow_analysis();
394 if (non_osr_flow->failing()) {
395 record_failure(non_osr_flow->failure_reason());
396 return NULL;
397 }
398 JsrSet* jsrs = new JsrSet(NULL, 16);
399 Block* non_osr_block = non_osr_flow->existing_block_at(start_bci(), jsrs);
400 if (non_osr_block == NULL) {
401 record_failure("cannot reach OSR point");
402 return NULL;
403 }
404 // load up the non-OSR state at this point
405 non_osr_block->copy_state_into(state);
406 int non_osr_start = non_osr_block->start();
407 if (non_osr_start != start_bci()) {
408 // must flow forward from it
409 if (CITraceTypeFlow) {
410 tty->print_cr(">> Interpreting pre-OSR block %d:", non_osr_start);
411 }
412 Block* block = block_at(non_osr_start, jsrs);
413 assert(block->limit() == start_bci(), "must flow forward to start");
414 flow_block(block, state, jsrs);
415 }
416 return state;
417 // Note: The code below would be an incorrect for an OSR flow,
418 // even if it were possible for an OSR entry point to be at bci zero.
419 }
420 // "Push" the method signature into the first few locals.
421 state->set_stack_size(-max_locals());
422 if (!method()->is_static()) {
423 ciType* holder = method()->holder();
424 if (holder->is_valuetype()) {
425 // The receiver is never null
426 holder = mark_as_never_null(holder);
427 }
428 state->push(holder);
429 assert(state->tos() == state->local(0), "");
430 }
431 for (ciSignatureStream str(method()->signature());
432 !str.at_return_type();
433 str.next()) {
434 ciType* arg = str.type();
435 if (str.is_never_null()) {
436 arg = mark_as_never_null(arg);
437 }
438 state->push_translate(arg);
439 }
440 // Set the rest of the locals to bottom.
441 Cell cell = state->next_cell(state->tos());
442 state->set_stack_size(0);
443 int limit = state->limit_cell();
444 for (; cell < limit; cell = state->next_cell(cell)) {
445 state->set_type_at(cell, state->bottom_type());
446 }
447 // Lock an object, if necessary.
448 state->set_monitor_count(method()->is_synchronized() ? 1 : 0);
449 return state;
450 }
451
452 // ------------------------------------------------------------------
453 // ciTypeFlow::StateVector::copy_into
454 //
455 // Copy our value into some other StateVector
456 void ciTypeFlow::StateVector::copy_into(ciTypeFlow::StateVector* copy)
457 const {
458 copy->set_stack_size(stack_size());
459 copy->set_monitor_count(monitor_count());
460 Cell limit = limit_cell();
461 for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
462 copy->set_type_at(c, type_at(c));
463 }
464 }
465
466 // ------------------------------------------------------------------
467 // ciTypeFlow::StateVector::meet
468 //
469 // Meets this StateVector with another, destructively modifying this
470 // one. Returns true if any modification takes place.
471 bool ciTypeFlow::StateVector::meet(const ciTypeFlow::StateVector* incoming) {
472 if (monitor_count() == -1) {
473 set_monitor_count(incoming->monitor_count());
474 }
475 assert(monitor_count() == incoming->monitor_count(), "monitors must match");
476
477 if (stack_size() == -1) {
478 set_stack_size(incoming->stack_size());
479 Cell limit = limit_cell();
480 #ifdef ASSERT
481 { for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
482 assert(type_at(c) == top_type(), "");
483 } }
484 #endif
485 // Make a simple copy of the incoming state.
486 for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
487 set_type_at(c, incoming->type_at(c));
488 }
489 return true; // it is always different the first time
490 }
491 #ifdef ASSERT
492 if (stack_size() != incoming->stack_size()) {
493 _outer->method()->print_codes();
494 tty->print_cr("!!!! Stack size conflict");
495 tty->print_cr("Current state:");
496 print_on(tty);
497 tty->print_cr("Incoming state:");
498 ((StateVector*)incoming)->print_on(tty);
499 }
500 #endif
501 assert(stack_size() == incoming->stack_size(), "sanity");
502
503 bool different = false;
504 Cell limit = limit_cell();
505 for (Cell c = start_cell(); c < limit; c = next_cell(c)) {
506 ciType* t1 = type_at(c);
507 ciType* t2 = incoming->type_at(c);
508 if (!t1->equals(t2)) {
509 ciType* new_type = type_meet(t1, t2);
510 if (!t1->equals(new_type)) {
511 set_type_at(c, new_type);
512 different = true;
513 }
514 }
515 }
516 return different;
517 }
518
519 // ------------------------------------------------------------------
520 // ciTypeFlow::StateVector::meet_exception
521 //
522 // Meets this StateVector with another, destructively modifying this
523 // one. The incoming state is coming via an exception. Returns true
524 // if any modification takes place.
525 bool ciTypeFlow::StateVector::meet_exception(ciInstanceKlass* exc,
526 const ciTypeFlow::StateVector* incoming) {
527 if (monitor_count() == -1) {
528 set_monitor_count(incoming->monitor_count());
529 }
530 assert(monitor_count() == incoming->monitor_count(), "monitors must match");
531
532 if (stack_size() == -1) {
533 set_stack_size(1);
534 }
535
536 assert(stack_size() == 1, "must have one-element stack");
537
538 bool different = false;
539
540 // Meet locals from incoming array.
541 Cell limit = local(_outer->max_locals()-1);
542 for (Cell c = start_cell(); c <= limit; c = next_cell(c)) {
543 ciType* t1 = type_at(c);
544 ciType* t2 = incoming->type_at(c);
545 if (!t1->equals(t2)) {
546 ciType* new_type = type_meet(t1, t2);
547 if (!t1->equals(new_type)) {
548 set_type_at(c, new_type);
549 different = true;
550 }
551 }
552 }
553
554 // Handle stack separately. When an exception occurs, the
555 // only stack entry is the exception instance.
556 ciType* tos_type = type_at_tos();
557 if (!tos_type->equals(exc)) {
558 ciType* new_type = type_meet(tos_type, exc);
559 if (!tos_type->equals(new_type)) {
560 set_type_at_tos(new_type);
561 different = true;
562 }
563 }
564
565 return different;
566 }
567
568 // ------------------------------------------------------------------
569 // ciTypeFlow::StateVector::push_translate
570 void ciTypeFlow::StateVector::push_translate(ciType* type) {
571 BasicType basic_type = type->basic_type();
572 if (basic_type == T_BOOLEAN || basic_type == T_CHAR ||
573 basic_type == T_BYTE || basic_type == T_SHORT) {
574 push_int();
575 } else {
576 push(type);
577 if (type->is_two_word()) {
578 push(half_type(type));
579 }
580 }
581 }
582
583 // ------------------------------------------------------------------
584 // ciTypeFlow::StateVector::do_aload
585 void ciTypeFlow::StateVector::do_aload(ciBytecodeStream* str) {
586 pop_int();
587 ciArrayKlass* array_klass = pop_objOrValueArray();
588 if (array_klass == NULL) {
589 // Did aload on a null reference; push a null and ignore the exception.
590 // This instruction will never continue normally. All we have to do
591 // is report a value that will meet correctly with any downstream
592 // reference types on paths that will truly be executed. This null type
593 // meets with any reference type to yield that same reference type.
594 // (The compiler will generate an unconditional exception here.)
595 push(null_type());
596 return;
597 }
598 if (!array_klass->is_loaded()) {
599 // Only fails for some -Xcomp runs
600 trap(str, array_klass,
601 Deoptimization::make_trap_request
602 (Deoptimization::Reason_unloaded,
603 Deoptimization::Action_reinterpret));
604 return;
605 }
606 ciKlass* element_klass = array_klass->element_klass();
607 if (!element_klass->is_loaded() && element_klass->is_instance_klass()) {
608 Untested("unloaded array element class in ciTypeFlow");
609 trap(str, element_klass,
610 Deoptimization::make_trap_request
611 (Deoptimization::Reason_unloaded,
612 Deoptimization::Action_reinterpret));
613 } else {
614 if (element_klass->is_valuetype()) {
615 // Value type array elements are never null
616 push(outer()->mark_as_never_null(element_klass));
617 } else {
618 push_object(element_klass);
619 }
620 }
621 }
622
623
624 // ------------------------------------------------------------------
625 // ciTypeFlow::StateVector::do_checkcast
626 void ciTypeFlow::StateVector::do_checkcast(ciBytecodeStream* str) {
627 bool will_link;
628 ciKlass* klass = str->get_klass(will_link);
629 if (!will_link) {
630 // VM's interpreter will not load 'klass' if object is NULL.
631 // Type flow after this block may still be needed in two situations:
632 // 1) C2 uses do_null_assert() and continues compilation for later blocks
633 // 2) C2 does an OSR compile in a later block (see bug 4778368).
634 pop_object();
635 do_null_assert(klass);
636 } else {
637 ciType* type = pop_value();
638 if (klass->is_valuetype() && (str->is_klass_never_null() || type->is_never_null())) {
639 // Casting to a Q-Type contains a NULL check
640 push(outer()->mark_as_never_null(klass));
641 } else {
642 push_object(klass);
643 }
644 }
645 }
646
647 // ------------------------------------------------------------------
648 // ciTypeFlow::StateVector::do_getfield
649 void ciTypeFlow::StateVector::do_getfield(ciBytecodeStream* str) {
650 // could add assert here for type of object.
651 pop_object();
652 do_getstatic(str);
653 }
654
655 // ------------------------------------------------------------------
656 // ciTypeFlow::StateVector::do_getstatic
657 void ciTypeFlow::StateVector::do_getstatic(ciBytecodeStream* str) {
658 bool will_link;
659 ciField* field = str->get_field(will_link);
660 if (!will_link) {
661 trap(str, field->holder(), str->get_field_holder_index());
662 } else {
663 ciType* field_type = field->type();
664 if (!field_type->is_loaded()) {
665 // Normally, we need the field's type to be loaded if we are to
666 // do anything interesting with its value.
667 // We used to do this: trap(str, str->get_field_signature_index());
668 //
669 // There is one good reason not to trap here. Execution can
670 // get past this "getfield" or "getstatic" if the value of
671 // the field is null. As long as the value is null, the class
672 // does not need to be loaded! The compiler must assume that
673 // the value of the unloaded class reference is null; if the code
674 // ever sees a non-null value, loading has occurred.
675 //
676 // This actually happens often enough to be annoying. If the
677 // compiler throws an uncommon trap at this bytecode, you can
678 // get an endless loop of recompilations, when all the code
679 // needs to do is load a series of null values. Also, a trap
680 // here can make an OSR entry point unreachable, triggering the
681 // assert on non_osr_block in ciTypeFlow::get_start_state.
682 // (See bug 4379915.)
683 do_null_assert(field_type->as_klass());
684 } else {
685 if (field->is_flattenable()) {
686 // A flattenable field is never null
687 field_type = outer()->mark_as_never_null(field_type);
688 }
689 push_translate(field_type);
690 }
691 }
692 }
693
694 // ------------------------------------------------------------------
695 // ciTypeFlow::StateVector::do_invoke
696 void ciTypeFlow::StateVector::do_invoke(ciBytecodeStream* str,
697 bool has_receiver) {
698 bool will_link;
699 ciSignature* declared_signature = NULL;
700 ciMethod* callee = str->get_method(will_link, &declared_signature);
701 assert(declared_signature != NULL, "cannot be null");
702 if (!will_link) {
703 // We weren't able to find the method.
704 if (str->cur_bc() == Bytecodes::_invokedynamic) {
705 trap(str, NULL,
706 Deoptimization::make_trap_request
707 (Deoptimization::Reason_uninitialized,
708 Deoptimization::Action_reinterpret));
709 } else {
710 ciKlass* unloaded_holder = callee->holder();
711 trap(str, unloaded_holder, str->get_method_holder_index());
712 }
713 } else {
714 // We are using the declared signature here because it might be
715 // different from the callee signature (Cf. invokedynamic and
716 // invokehandle).
717 ciSignatureStream sigstr(declared_signature);
718 const int arg_size = declared_signature->size();
719 const int stack_base = stack_size() - arg_size;
720 int i = 0;
721 for( ; !sigstr.at_return_type(); sigstr.next()) {
722 ciType* type = sigstr.type();
723 ciType* stack_type = type_at(stack(stack_base + i++));
724 // Do I want to check this type?
725 // assert(stack_type->is_subtype_of(type), "bad type for field value");
726 if (type->is_two_word()) {
727 ciType* stack_type2 = type_at(stack(stack_base + i++));
728 assert(stack_type2->equals(half_type(type)), "must be 2nd half");
729 }
730 }
731 assert(arg_size == i, "must match");
732 for (int j = 0; j < arg_size; j++) {
733 pop();
734 }
735 if (has_receiver) {
736 // Check this?
737 pop_object();
738 }
739 assert(!sigstr.is_done(), "must have return type");
740 ciType* return_type = sigstr.type();
741 if (!return_type->is_void()) {
742 if (!return_type->is_loaded()) {
743 // As in do_getstatic(), generally speaking, we need the return type to
744 // be loaded if we are to do anything interesting with its value.
745 // We used to do this: trap(str, str->get_method_signature_index());
746 //
747 // We do not trap here since execution can get past this invoke if
748 // the return value is null. As long as the value is null, the class
749 // does not need to be loaded! The compiler must assume that
750 // the value of the unloaded class reference is null; if the code
751 // ever sees a non-null value, loading has occurred.
752 //
753 // See do_getstatic() for similar explanation, as well as bug 4684993.
754 do_null_assert(return_type->as_klass());
755 } else {
756 if (sigstr.is_never_null()) {
757 return_type = outer()->mark_as_never_null(return_type);
758 }
759 push_translate(return_type);
760 }
761 }
762 }
763 }
764
765 // ------------------------------------------------------------------
766 // ciTypeFlow::StateVector::do_jsr
767 void ciTypeFlow::StateVector::do_jsr(ciBytecodeStream* str) {
768 push(ciReturnAddress::make(str->next_bci()));
769 }
770
771 // ------------------------------------------------------------------
772 // ciTypeFlow::StateVector::do_ldc
773 void ciTypeFlow::StateVector::do_ldc(ciBytecodeStream* str) {
774 ciConstant con = str->get_constant();
775 BasicType basic_type = con.basic_type();
776 if (basic_type == T_ILLEGAL) {
777 // OutOfMemoryError in the CI while loading constant
778 push_null();
779 outer()->record_failure("ldc did not link");
780 return;
781 }
782 if (basic_type == T_OBJECT || basic_type == T_VALUETYPE || basic_type == T_ARRAY) {
783 ciObject* obj = con.as_object();
784 if (obj->is_null_object()) {
785 push_null();
786 } else {
787 assert(obj->is_instance() || obj->is_array(), "must be java_mirror of klass");
788 ciType* type = obj->klass();
789 if (type->is_valuetype()) {
790 type = outer()->mark_as_never_null(type);
791 }
792 push(type);
793 }
794 } else {
795 push_translate(ciType::make(basic_type));
796 }
797 }
798
799 // ------------------------------------------------------------------
800 // ciTypeFlow::StateVector::do_multianewarray
801 void ciTypeFlow::StateVector::do_multianewarray(ciBytecodeStream* str) {
802 int dimensions = str->get_dimensions();
803 bool will_link;
804 ciArrayKlass* array_klass = str->get_klass(will_link)->as_array_klass();
805 if (!will_link) {
806 trap(str, array_klass, str->get_klass_index());
807 } else {
808 for (int i = 0; i < dimensions; i++) {
809 pop_int();
810 }
811 push_object(array_klass);
812 }
813 }
814
815 // ------------------------------------------------------------------
816 // ciTypeFlow::StateVector::do_new
817 void ciTypeFlow::StateVector::do_new(ciBytecodeStream* str) {
818 bool will_link;
819 ciKlass* klass = str->get_klass(will_link);
820 if (!will_link || str->is_unresolved_klass()) {
821 trap(str, klass, str->get_klass_index());
822 } else {
823 push_object(klass);
824 }
825 }
826
827 // ------------------------------------------------------------------
828 // ciTypeFlow::StateVector::do_defaultvalue
829 void ciTypeFlow::StateVector::do_defaultvalue(ciBytecodeStream* str) {
830 bool will_link;
831 ciKlass* klass = str->get_klass(will_link);
832 if (!will_link) {
833 trap(str, klass, str->get_klass_index());
834 } else {
835 // The default value type is never null
836 push(outer()->mark_as_never_null(klass));
837 }
838 }
839
840 // ------------------------------------------------------------------
841 // ciTypeFlow::StateVector::do_withfield
842 void ciTypeFlow::StateVector::do_withfield(ciBytecodeStream* str) {
843 bool will_link;
844 ciField* field = str->get_field(will_link);
845 ciKlass* klass = field->holder();
846 if (!will_link) {
847 trap(str, klass, str->get_field_holder_index());
848 } else {
849 ciType* type = pop_value();
850 ciType* field_type = field->type();
851 assert(field_type->is_loaded(), "field type must be loaded");
852 if (field_type->is_two_word()) {
853 ciType* type2 = pop_value();
854 assert(type2->is_two_word(), "must be 2nd half");
855 assert(type == half_type(type2), "must be 2nd half");
856 }
857 pop_object();
858 // The newly created value type can never be null
859 push(outer()->mark_as_never_null(klass));
860 }
861 }
862
863 // ------------------------------------------------------------------
864 // ciTypeFlow::StateVector::do_newarray
865 void ciTypeFlow::StateVector::do_newarray(ciBytecodeStream* str) {
866 pop_int();
867 ciKlass* klass = ciTypeArrayKlass::make((BasicType)str->get_index());
868 push_object(klass);
869 }
870
871 // ------------------------------------------------------------------
872 // ciTypeFlow::StateVector::do_putfield
873 void ciTypeFlow::StateVector::do_putfield(ciBytecodeStream* str) {
874 do_putstatic(str);
875 if (_trap_bci != -1) return; // unloaded field holder, etc.
876 // could add assert here for type of object.
877 pop_object();
878 }
879
880 // ------------------------------------------------------------------
881 // ciTypeFlow::StateVector::do_putstatic
882 void ciTypeFlow::StateVector::do_putstatic(ciBytecodeStream* str) {
883 bool will_link;
884 ciField* field = str->get_field(will_link);
885 if (!will_link) {
886 trap(str, field->holder(), str->get_field_holder_index());
887 } else {
888 ciType* field_type = field->type();
889 ciType* type = pop_value();
890 // Do I want to check this type?
891 // assert(type->is_subtype_of(field_type), "bad type for field value");
892 if (field_type->is_two_word()) {
893 ciType* type2 = pop_value();
894 assert(type2->is_two_word(), "must be 2nd half");
895 assert(type == half_type(type2), "must be 2nd half");
896 }
897 }
898 }
899
900 // ------------------------------------------------------------------
901 // ciTypeFlow::StateVector::do_ret
902 void ciTypeFlow::StateVector::do_ret(ciBytecodeStream* str) {
903 Cell index = local(str->get_index());
904
905 ciType* address = type_at(index);
906 assert(address->is_return_address(), "bad return address");
907 set_type_at(index, bottom_type());
908 }
909
910 // ------------------------------------------------------------------
911 // ciTypeFlow::StateVector::trap
912 //
913 // Stop interpretation of this path with a trap.
914 void ciTypeFlow::StateVector::trap(ciBytecodeStream* str, ciKlass* klass, int index) {
915 _trap_bci = str->cur_bci();
916 _trap_index = index;
917
918 // Log information about this trap:
919 CompileLog* log = outer()->env()->log();
920 if (log != NULL) {
921 int mid = log->identify(outer()->method());
922 int kid = (klass == NULL)? -1: log->identify(klass);
923 log->begin_elem("uncommon_trap method='%d' bci='%d'", mid, str->cur_bci());
924 char buf[100];
925 log->print(" %s", Deoptimization::format_trap_request(buf, sizeof(buf),
926 index));
927 if (kid >= 0)
928 log->print(" klass='%d'", kid);
929 log->end_elem();
930 }
931 }
932
933 // ------------------------------------------------------------------
934 // ciTypeFlow::StateVector::do_null_assert
935 // Corresponds to graphKit::do_null_assert.
936 void ciTypeFlow::StateVector::do_null_assert(ciKlass* unloaded_klass) {
937 if (unloaded_klass->is_loaded()) {
938 // We failed to link, but we can still compute with this class,
939 // since it is loaded somewhere. The compiler will uncommon_trap
940 // if the object is not null, but the typeflow pass can not assume
941 // that the object will be null, otherwise it may incorrectly tell
942 // the parser that an object is known to be null. 4761344, 4807707
943 push_object(unloaded_klass);
944 } else {
945 // The class is not loaded anywhere. It is safe to model the
946 // null in the typestates, because we can compile in a null check
947 // which will deoptimize us if someone manages to load the
948 // class later.
949 push_null();
950 }
951 }
952
953
954 // ------------------------------------------------------------------
955 // ciTypeFlow::StateVector::apply_one_bytecode
956 //
957 // Apply the effect of one bytecode to this StateVector
958 bool ciTypeFlow::StateVector::apply_one_bytecode(ciBytecodeStream* str) {
959 _trap_bci = -1;
960 _trap_index = 0;
961
962 if (CITraceTypeFlow) {
963 tty->print_cr(">> Interpreting bytecode %d:%s", str->cur_bci(),
964 Bytecodes::name(str->cur_bc()));
965 }
966
967 switch(str->cur_bc()) {
968 case Bytecodes::_aaload: do_aload(str); break;
969
970 case Bytecodes::_aastore:
971 {
972 pop_object();
973 pop_int();
974 pop_objOrValueArray();
975 break;
976 }
977 case Bytecodes::_aconst_null:
978 {
979 push_null();
980 break;
981 }
982 case Bytecodes::_aload: load_local_object(str->get_index()); break;
983 case Bytecodes::_aload_0: load_local_object(0); break;
984 case Bytecodes::_aload_1: load_local_object(1); break;
985 case Bytecodes::_aload_2: load_local_object(2); break;
986 case Bytecodes::_aload_3: load_local_object(3); break;
987
988 case Bytecodes::_anewarray:
989 {
990 pop_int();
991 bool will_link;
992 ciKlass* element_klass = str->get_klass(will_link);
993 if (!will_link) {
994 trap(str, element_klass, str->get_klass_index());
995 } else {
996 bool never_null = str->is_klass_never_null();
997 push_object(ciArrayKlass::make(element_klass, never_null));
998 }
999 break;
1000 }
1001 case Bytecodes::_areturn:
1002 case Bytecodes::_ifnonnull:
1003 case Bytecodes::_ifnull:
1004 {
1005 pop_object();
1006 break;
1007 }
1008 case Bytecodes::_monitorenter:
1009 {
1010 pop_object();
1011 set_monitor_count(monitor_count() + 1);
1012 break;
1013 }
1014 case Bytecodes::_monitorexit:
1015 {
1016 pop_object();
1017 assert(monitor_count() > 0, "must be a monitor to exit from");
1018 set_monitor_count(monitor_count() - 1);
1019 break;
1020 }
1021 case Bytecodes::_arraylength:
1022 {
1023 pop_array();
1024 push_int();
1025 break;
1026 }
1027 case Bytecodes::_astore: store_local_object(str->get_index()); break;
1028 case Bytecodes::_astore_0: store_local_object(0); break;
1029 case Bytecodes::_astore_1: store_local_object(1); break;
1030 case Bytecodes::_astore_2: store_local_object(2); break;
1031 case Bytecodes::_astore_3: store_local_object(3); break;
1032
1033 case Bytecodes::_athrow:
1034 {
1035 NEEDS_CLEANUP;
1036 pop_object();
1037 break;
1038 }
1039 case Bytecodes::_baload:
1040 case Bytecodes::_caload:
1041 case Bytecodes::_iaload:
1042 case Bytecodes::_saload:
1043 {
1044 pop_int();
1045 ciTypeArrayKlass* array_klass = pop_typeArray();
1046 // Put assert here for right type?
1047 push_int();
1048 break;
1049 }
1050 case Bytecodes::_bastore:
1051 case Bytecodes::_castore:
1052 case Bytecodes::_iastore:
1053 case Bytecodes::_sastore:
1054 {
1055 pop_int();
1056 pop_int();
1057 pop_typeArray();
1058 // assert here?
1059 break;
1060 }
1061 case Bytecodes::_bipush:
1062 case Bytecodes::_iconst_m1:
1063 case Bytecodes::_iconst_0:
1064 case Bytecodes::_iconst_1:
1065 case Bytecodes::_iconst_2:
1066 case Bytecodes::_iconst_3:
1067 case Bytecodes::_iconst_4:
1068 case Bytecodes::_iconst_5:
1069 case Bytecodes::_sipush:
1070 {
1071 push_int();
1072 break;
1073 }
1074 case Bytecodes::_checkcast: do_checkcast(str); break;
1075
1076 case Bytecodes::_d2f:
1077 {
1078 pop_double();
1079 push_float();
1080 break;
1081 }
1082 case Bytecodes::_d2i:
1083 {
1084 pop_double();
1085 push_int();
1086 break;
1087 }
1088 case Bytecodes::_d2l:
1089 {
1090 pop_double();
1091 push_long();
1092 break;
1093 }
1094 case Bytecodes::_dadd:
1095 case Bytecodes::_ddiv:
1096 case Bytecodes::_dmul:
1097 case Bytecodes::_drem:
1098 case Bytecodes::_dsub:
1099 {
1100 pop_double();
1101 pop_double();
1102 push_double();
1103 break;
1104 }
1105 case Bytecodes::_daload:
1106 {
1107 pop_int();
1108 ciTypeArrayKlass* array_klass = pop_typeArray();
1109 // Put assert here for right type?
1110 push_double();
1111 break;
1112 }
1113 case Bytecodes::_dastore:
1114 {
1115 pop_double();
1116 pop_int();
1117 pop_typeArray();
1118 // assert here?
1119 break;
1120 }
1121 case Bytecodes::_dcmpg:
1122 case Bytecodes::_dcmpl:
1123 {
1124 pop_double();
1125 pop_double();
1126 push_int();
1127 break;
1128 }
1129 case Bytecodes::_dconst_0:
1130 case Bytecodes::_dconst_1:
1131 {
1132 push_double();
1133 break;
1134 }
1135 case Bytecodes::_dload: load_local_double(str->get_index()); break;
1136 case Bytecodes::_dload_0: load_local_double(0); break;
1137 case Bytecodes::_dload_1: load_local_double(1); break;
1138 case Bytecodes::_dload_2: load_local_double(2); break;
1139 case Bytecodes::_dload_3: load_local_double(3); break;
1140
1141 case Bytecodes::_dneg:
1142 {
1143 pop_double();
1144 push_double();
1145 break;
1146 }
1147 case Bytecodes::_dreturn:
1148 {
1149 pop_double();
1150 break;
1151 }
1152 case Bytecodes::_dstore: store_local_double(str->get_index()); break;
1153 case Bytecodes::_dstore_0: store_local_double(0); break;
1154 case Bytecodes::_dstore_1: store_local_double(1); break;
1155 case Bytecodes::_dstore_2: store_local_double(2); break;
1156 case Bytecodes::_dstore_3: store_local_double(3); break;
1157
1158 case Bytecodes::_dup:
1159 {
1160 push(type_at_tos());
1161 break;
1162 }
1163 case Bytecodes::_dup_x1:
1164 {
1165 ciType* value1 = pop_value();
1166 ciType* value2 = pop_value();
1167 push(value1);
1168 push(value2);
1169 push(value1);
1170 break;
1171 }
1172 case Bytecodes::_dup_x2:
1173 {
1174 ciType* value1 = pop_value();
1175 ciType* value2 = pop_value();
1176 ciType* value3 = pop_value();
1177 push(value1);
1178 push(value3);
1179 push(value2);
1180 push(value1);
1181 break;
1182 }
1183 case Bytecodes::_dup2:
1184 {
1185 ciType* value1 = pop_value();
1186 ciType* value2 = pop_value();
1187 push(value2);
1188 push(value1);
1189 push(value2);
1190 push(value1);
1191 break;
1192 }
1193 case Bytecodes::_dup2_x1:
1194 {
1195 ciType* value1 = pop_value();
1196 ciType* value2 = pop_value();
1197 ciType* value3 = pop_value();
1198 push(value2);
1199 push(value1);
1200 push(value3);
1201 push(value2);
1202 push(value1);
1203 break;
1204 }
1205 case Bytecodes::_dup2_x2:
1206 {
1207 ciType* value1 = pop_value();
1208 ciType* value2 = pop_value();
1209 ciType* value3 = pop_value();
1210 ciType* value4 = pop_value();
1211 push(value2);
1212 push(value1);
1213 push(value4);
1214 push(value3);
1215 push(value2);
1216 push(value1);
1217 break;
1218 }
1219 case Bytecodes::_f2d:
1220 {
1221 pop_float();
1222 push_double();
1223 break;
1224 }
1225 case Bytecodes::_f2i:
1226 {
1227 pop_float();
1228 push_int();
1229 break;
1230 }
1231 case Bytecodes::_f2l:
1232 {
1233 pop_float();
1234 push_long();
1235 break;
1236 }
1237 case Bytecodes::_fadd:
1238 case Bytecodes::_fdiv:
1239 case Bytecodes::_fmul:
1240 case Bytecodes::_frem:
1241 case Bytecodes::_fsub:
1242 {
1243 pop_float();
1244 pop_float();
1245 push_float();
1246 break;
1247 }
1248 case Bytecodes::_faload:
1249 {
1250 pop_int();
1251 ciTypeArrayKlass* array_klass = pop_typeArray();
1252 // Put assert here.
1253 push_float();
1254 break;
1255 }
1256 case Bytecodes::_fastore:
1257 {
1258 pop_float();
1259 pop_int();
1260 ciTypeArrayKlass* array_klass = pop_typeArray();
1261 // Put assert here.
1262 break;
1263 }
1264 case Bytecodes::_fcmpg:
1265 case Bytecodes::_fcmpl:
1266 {
1267 pop_float();
1268 pop_float();
1269 push_int();
1270 break;
1271 }
1272 case Bytecodes::_fconst_0:
1273 case Bytecodes::_fconst_1:
1274 case Bytecodes::_fconst_2:
1275 {
1276 push_float();
1277 break;
1278 }
1279 case Bytecodes::_fload: load_local_float(str->get_index()); break;
1280 case Bytecodes::_fload_0: load_local_float(0); break;
1281 case Bytecodes::_fload_1: load_local_float(1); break;
1282 case Bytecodes::_fload_2: load_local_float(2); break;
1283 case Bytecodes::_fload_3: load_local_float(3); break;
1284
1285 case Bytecodes::_fneg:
1286 {
1287 pop_float();
1288 push_float();
1289 break;
1290 }
1291 case Bytecodes::_freturn:
1292 {
1293 pop_float();
1294 break;
1295 }
1296 case Bytecodes::_fstore: store_local_float(str->get_index()); break;
1297 case Bytecodes::_fstore_0: store_local_float(0); break;
1298 case Bytecodes::_fstore_1: store_local_float(1); break;
1299 case Bytecodes::_fstore_2: store_local_float(2); break;
1300 case Bytecodes::_fstore_3: store_local_float(3); break;
1301
1302 case Bytecodes::_getfield: do_getfield(str); break;
1303 case Bytecodes::_getstatic: do_getstatic(str); break;
1304
1305 case Bytecodes::_goto:
1306 case Bytecodes::_goto_w:
1307 case Bytecodes::_nop:
1308 case Bytecodes::_return:
1309 {
1310 // do nothing.
1311 break;
1312 }
1313 case Bytecodes::_i2b:
1314 case Bytecodes::_i2c:
1315 case Bytecodes::_i2s:
1316 case Bytecodes::_ineg:
1317 {
1318 pop_int();
1319 push_int();
1320 break;
1321 }
1322 case Bytecodes::_i2d:
1323 {
1324 pop_int();
1325 push_double();
1326 break;
1327 }
1328 case Bytecodes::_i2f:
1329 {
1330 pop_int();
1331 push_float();
1332 break;
1333 }
1334 case Bytecodes::_i2l:
1335 {
1336 pop_int();
1337 push_long();
1338 break;
1339 }
1340 case Bytecodes::_iadd:
1341 case Bytecodes::_iand:
1342 case Bytecodes::_idiv:
1343 case Bytecodes::_imul:
1344 case Bytecodes::_ior:
1345 case Bytecodes::_irem:
1346 case Bytecodes::_ishl:
1347 case Bytecodes::_ishr:
1348 case Bytecodes::_isub:
1349 case Bytecodes::_iushr:
1350 case Bytecodes::_ixor:
1351 {
1352 pop_int();
1353 pop_int();
1354 push_int();
1355 break;
1356 }
1357 case Bytecodes::_if_acmpeq:
1358 case Bytecodes::_if_acmpne:
1359 {
1360 pop_object();
1361 pop_object();
1362 break;
1363 }
1364 case Bytecodes::_if_icmpeq:
1365 case Bytecodes::_if_icmpge:
1366 case Bytecodes::_if_icmpgt:
1367 case Bytecodes::_if_icmple:
1368 case Bytecodes::_if_icmplt:
1369 case Bytecodes::_if_icmpne:
1370 {
1371 pop_int();
1372 pop_int();
1373 break;
1374 }
1375 case Bytecodes::_ifeq:
1376 case Bytecodes::_ifle:
1377 case Bytecodes::_iflt:
1378 case Bytecodes::_ifge:
1379 case Bytecodes::_ifgt:
1380 case Bytecodes::_ifne:
1381 case Bytecodes::_ireturn:
1382 case Bytecodes::_lookupswitch:
1383 case Bytecodes::_tableswitch:
1384 {
1385 pop_int();
1386 break;
1387 }
1388 case Bytecodes::_iinc:
1389 {
1390 int lnum = str->get_index();
1391 check_int(local(lnum));
1392 store_to_local(lnum);
1393 break;
1394 }
1395 case Bytecodes::_iload: load_local_int(str->get_index()); break;
1396 case Bytecodes::_iload_0: load_local_int(0); break;
1397 case Bytecodes::_iload_1: load_local_int(1); break;
1398 case Bytecodes::_iload_2: load_local_int(2); break;
1399 case Bytecodes::_iload_3: load_local_int(3); break;
1400
1401 case Bytecodes::_instanceof:
1402 {
1403 // Check for uncommon trap:
1404 do_checkcast(str);
1405 pop_object();
1406 push_int();
1407 break;
1408 }
1409 case Bytecodes::_invokeinterface: do_invoke(str, true); break;
1410 case Bytecodes::_invokespecial: do_invoke(str, true); break;
1411 case Bytecodes::_invokestatic: do_invoke(str, false); break;
1412 case Bytecodes::_invokevirtual: do_invoke(str, true); break;
1413 case Bytecodes::_invokedynamic: do_invoke(str, false); break;
1414
1415 case Bytecodes::_istore: store_local_int(str->get_index()); break;
1416 case Bytecodes::_istore_0: store_local_int(0); break;
1417 case Bytecodes::_istore_1: store_local_int(1); break;
1418 case Bytecodes::_istore_2: store_local_int(2); break;
1419 case Bytecodes::_istore_3: store_local_int(3); break;
1420
1421 case Bytecodes::_jsr:
1422 case Bytecodes::_jsr_w: do_jsr(str); break;
1423
1424 case Bytecodes::_l2d:
1425 {
1426 pop_long();
1427 push_double();
1428 break;
1429 }
1430 case Bytecodes::_l2f:
1431 {
1432 pop_long();
1433 push_float();
1434 break;
1435 }
1436 case Bytecodes::_l2i:
1437 {
1438 pop_long();
1439 push_int();
1440 break;
1441 }
1442 case Bytecodes::_ladd:
1443 case Bytecodes::_land:
1444 case Bytecodes::_ldiv:
1445 case Bytecodes::_lmul:
1446 case Bytecodes::_lor:
1447 case Bytecodes::_lrem:
1448 case Bytecodes::_lsub:
1449 case Bytecodes::_lxor:
1450 {
1451 pop_long();
1452 pop_long();
1453 push_long();
1454 break;
1455 }
1456 case Bytecodes::_laload:
1457 {
1458 pop_int();
1459 ciTypeArrayKlass* array_klass = pop_typeArray();
1460 // Put assert here for right type?
1461 push_long();
1462 break;
1463 }
1464 case Bytecodes::_lastore:
1465 {
1466 pop_long();
1467 pop_int();
1468 pop_typeArray();
1469 // assert here?
1470 break;
1471 }
1472 case Bytecodes::_lcmp:
1473 {
1474 pop_long();
1475 pop_long();
1476 push_int();
1477 break;
1478 }
1479 case Bytecodes::_lconst_0:
1480 case Bytecodes::_lconst_1:
1481 {
1482 push_long();
1483 break;
1484 }
1485 case Bytecodes::_ldc:
1486 case Bytecodes::_ldc_w:
1487 case Bytecodes::_ldc2_w:
1488 {
1489 do_ldc(str);
1490 break;
1491 }
1492
1493 case Bytecodes::_lload: load_local_long(str->get_index()); break;
1494 case Bytecodes::_lload_0: load_local_long(0); break;
1495 case Bytecodes::_lload_1: load_local_long(1); break;
1496 case Bytecodes::_lload_2: load_local_long(2); break;
1497 case Bytecodes::_lload_3: load_local_long(3); break;
1498
1499 case Bytecodes::_lneg:
1500 {
1501 pop_long();
1502 push_long();
1503 break;
1504 }
1505 case Bytecodes::_lreturn:
1506 {
1507 pop_long();
1508 break;
1509 }
1510 case Bytecodes::_lshl:
1511 case Bytecodes::_lshr:
1512 case Bytecodes::_lushr:
1513 {
1514 pop_int();
1515 pop_long();
1516 push_long();
1517 break;
1518 }
1519 case Bytecodes::_lstore: store_local_long(str->get_index()); break;
1520 case Bytecodes::_lstore_0: store_local_long(0); break;
1521 case Bytecodes::_lstore_1: store_local_long(1); break;
1522 case Bytecodes::_lstore_2: store_local_long(2); break;
1523 case Bytecodes::_lstore_3: store_local_long(3); break;
1524
1525 case Bytecodes::_multianewarray: do_multianewarray(str); break;
1526
1527 case Bytecodes::_new: do_new(str); break;
1528
1529 case Bytecodes::_defaultvalue: do_defaultvalue(str); break;
1530 case Bytecodes::_withfield: do_withfield(str); break;
1531
1532 case Bytecodes::_newarray: do_newarray(str); break;
1533
1534 case Bytecodes::_pop:
1535 {
1536 pop();
1537 break;
1538 }
1539 case Bytecodes::_pop2:
1540 {
1541 pop();
1542 pop();
1543 break;
1544 }
1545
1546 case Bytecodes::_putfield: do_putfield(str); break;
1547 case Bytecodes::_putstatic: do_putstatic(str); break;
1548
1549 case Bytecodes::_ret: do_ret(str); break;
1550
1551 case Bytecodes::_swap:
1552 {
1553 ciType* value1 = pop_value();
1554 ciType* value2 = pop_value();
1555 push(value1);
1556 push(value2);
1557 break;
1558 }
1559
1560 case Bytecodes::_wide:
1561 default:
1562 {
1563 // The iterator should skip this.
1564 ShouldNotReachHere();
1565 break;
1566 }
1567 }
1568
1569 if (CITraceTypeFlow) {
1570 print_on(tty);
1571 }
1572
1573 return (_trap_bci != -1);
1574 }
1575
1576 #ifndef PRODUCT
1577 // ------------------------------------------------------------------
1578 // ciTypeFlow::StateVector::print_cell_on
1579 void ciTypeFlow::StateVector::print_cell_on(outputStream* st, Cell c) const {
1580 ciType* type = type_at(c);
1581 if (type == top_type()) {
1582 st->print("top");
1583 } else if (type == bottom_type()) {
1584 st->print("bottom");
1585 } else if (type == null_type()) {
1586 st->print("null");
1587 } else if (type == long2_type()) {
1588 st->print("long2");
1589 } else if (type == double2_type()) {
1590 st->print("double2");
1591 } else if (is_int(type)) {
1592 st->print("int");
1593 } else if (is_long(type)) {
1594 st->print("long");
1595 } else if (is_float(type)) {
1596 st->print("float");
1597 } else if (is_double(type)) {
1598 st->print("double");
1599 } else if (type->is_return_address()) {
1600 st->print("address(%d)", type->as_return_address()->bci());
1601 } else {
1602 if (type->is_klass()) {
1603 type->as_klass()->name()->print_symbol_on(st);
1604 } else {
1605 st->print("UNEXPECTED TYPE");
1606 type->print();
1607 }
1608 }
1609 }
1610
1611 // ------------------------------------------------------------------
1612 // ciTypeFlow::StateVector::print_on
1613 void ciTypeFlow::StateVector::print_on(outputStream* st) const {
1614 int num_locals = _outer->max_locals();
1615 int num_stack = stack_size();
1616 int num_monitors = monitor_count();
1617 st->print_cr(" State : locals %d, stack %d, monitors %d", num_locals, num_stack, num_monitors);
1618 if (num_stack >= 0) {
1619 int i;
1620 for (i = 0; i < num_locals; i++) {
1621 st->print(" local %2d : ", i);
1622 print_cell_on(st, local(i));
1623 st->cr();
1624 }
1625 for (i = 0; i < num_stack; i++) {
1626 st->print(" stack %2d : ", i);
1627 print_cell_on(st, stack(i));
1628 st->cr();
1629 }
1630 }
1631 }
1632 #endif
1633
1634
1635 // ------------------------------------------------------------------
1636 // ciTypeFlow::SuccIter::next
1637 //
1638 void ciTypeFlow::SuccIter::next() {
1639 int succ_ct = _pred->successors()->length();
1640 int next = _index + 1;
1641 if (next < succ_ct) {
1642 _index = next;
1643 _succ = _pred->successors()->at(next);
1644 return;
1645 }
1646 for (int i = next - succ_ct; i < _pred->exceptions()->length(); i++) {
1647 // Do not compile any code for unloaded exception types.
1648 // Following compiler passes are responsible for doing this also.
1649 ciInstanceKlass* exception_klass = _pred->exc_klasses()->at(i);
1650 if (exception_klass->is_loaded()) {
1651 _index = next;
1652 _succ = _pred->exceptions()->at(i);
1653 return;
1654 }
1655 next++;
1656 }
1657 _index = -1;
1658 _succ = NULL;
1659 }
1660
1661 // ------------------------------------------------------------------
1662 // ciTypeFlow::SuccIter::set_succ
1663 //
1664 void ciTypeFlow::SuccIter::set_succ(Block* succ) {
1665 int succ_ct = _pred->successors()->length();
1666 if (_index < succ_ct) {
1667 _pred->successors()->at_put(_index, succ);
1668 } else {
1669 int idx = _index - succ_ct;
1670 _pred->exceptions()->at_put(idx, succ);
1671 }
1672 }
1673
1674 // ciTypeFlow::Block
1675 //
1676 // A basic block.
1677
1678 // ------------------------------------------------------------------
1679 // ciTypeFlow::Block::Block
1680 ciTypeFlow::Block::Block(ciTypeFlow* outer,
1681 ciBlock *ciblk,
1682 ciTypeFlow::JsrSet* jsrs) {
1683 _ciblock = ciblk;
1684 _exceptions = NULL;
1685 _exc_klasses = NULL;
1686 _successors = NULL;
1687 _predecessors = new (outer->arena()) GrowableArray<Block*>(outer->arena(), 1, 0, NULL);
1688 _state = new (outer->arena()) StateVector(outer);
1689 JsrSet* new_jsrs =
1690 new (outer->arena()) JsrSet(outer->arena(), jsrs->size());
1691 jsrs->copy_into(new_jsrs);
1692 _jsrs = new_jsrs;
1693 _next = NULL;
1694 _on_work_list = false;
1695 _backedge_copy = false;
1696 _has_monitorenter = false;
1697 _trap_bci = -1;
1698 _trap_index = 0;
1699 df_init();
1700
1701 if (CITraceTypeFlow) {
1702 tty->print_cr(">> Created new block");
1703 print_on(tty);
1704 }
1705
1706 assert(this->outer() == outer, "outer link set up");
1707 assert(!outer->have_block_count(), "must not have mapped blocks yet");
1708 }
1709
1710 // ------------------------------------------------------------------
1711 // ciTypeFlow::Block::df_init
1712 void ciTypeFlow::Block::df_init() {
1713 _pre_order = -1; assert(!has_pre_order(), "");
1714 _post_order = -1; assert(!has_post_order(), "");
1715 _loop = NULL;
1716 _irreducible_entry = false;
1717 _rpo_next = NULL;
1718 }
1719
1720 // ------------------------------------------------------------------
1721 // ciTypeFlow::Block::successors
1722 //
1723 // Get the successors for this Block.
1724 GrowableArray<ciTypeFlow::Block*>*
1725 ciTypeFlow::Block::successors(ciBytecodeStream* str,
1726 ciTypeFlow::StateVector* state,
1727 ciTypeFlow::JsrSet* jsrs) {
1728 if (_successors == NULL) {
1729 if (CITraceTypeFlow) {
1730 tty->print(">> Computing successors for block ");
1731 print_value_on(tty);
1732 tty->cr();
1733 }
1734
1735 ciTypeFlow* analyzer = outer();
1736 Arena* arena = analyzer->arena();
1737 Block* block = NULL;
1738 bool has_successor = !has_trap() &&
1739 (control() != ciBlock::fall_through_bci || limit() < analyzer->code_size());
1740 if (!has_successor) {
1741 _successors =
1742 new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1743 // No successors
1744 } else if (control() == ciBlock::fall_through_bci) {
1745 assert(str->cur_bci() == limit(), "bad block end");
1746 // This block simply falls through to the next.
1747 _successors =
1748 new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1749
1750 Block* block = analyzer->block_at(limit(), _jsrs);
1751 assert(_successors->length() == FALL_THROUGH, "");
1752 _successors->append(block);
1753 } else {
1754 int current_bci = str->cur_bci();
1755 int next_bci = str->next_bci();
1756 int branch_bci = -1;
1757 Block* target = NULL;
1758 assert(str->next_bci() == limit(), "bad block end");
1759 // This block is not a simple fall-though. Interpret
1760 // the current bytecode to find our successors.
1761 switch (str->cur_bc()) {
1762 case Bytecodes::_ifeq: case Bytecodes::_ifne:
1763 case Bytecodes::_iflt: case Bytecodes::_ifge:
1764 case Bytecodes::_ifgt: case Bytecodes::_ifle:
1765 case Bytecodes::_if_icmpeq: case Bytecodes::_if_icmpne:
1766 case Bytecodes::_if_icmplt: case Bytecodes::_if_icmpge:
1767 case Bytecodes::_if_icmpgt: case Bytecodes::_if_icmple:
1768 case Bytecodes::_if_acmpeq: case Bytecodes::_if_acmpne:
1769 case Bytecodes::_ifnull: case Bytecodes::_ifnonnull:
1770 // Our successors are the branch target and the next bci.
1771 branch_bci = str->get_dest();
1772 _successors =
1773 new (arena) GrowableArray<Block*>(arena, 2, 0, NULL);
1774 assert(_successors->length() == IF_NOT_TAKEN, "");
1775 _successors->append(analyzer->block_at(next_bci, jsrs));
1776 assert(_successors->length() == IF_TAKEN, "");
1777 _successors->append(analyzer->block_at(branch_bci, jsrs));
1778 break;
1779
1780 case Bytecodes::_goto:
1781 branch_bci = str->get_dest();
1782 _successors =
1783 new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1784 assert(_successors->length() == GOTO_TARGET, "");
1785 _successors->append(analyzer->block_at(branch_bci, jsrs));
1786 break;
1787
1788 case Bytecodes::_jsr:
1789 branch_bci = str->get_dest();
1790 _successors =
1791 new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1792 assert(_successors->length() == GOTO_TARGET, "");
1793 _successors->append(analyzer->block_at(branch_bci, jsrs));
1794 break;
1795
1796 case Bytecodes::_goto_w:
1797 case Bytecodes::_jsr_w:
1798 _successors =
1799 new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1800 assert(_successors->length() == GOTO_TARGET, "");
1801 _successors->append(analyzer->block_at(str->get_far_dest(), jsrs));
1802 break;
1803
1804 case Bytecodes::_tableswitch: {
1805 Bytecode_tableswitch tableswitch(str);
1806
1807 int len = tableswitch.length();
1808 _successors =
1809 new (arena) GrowableArray<Block*>(arena, len+1, 0, NULL);
1810 int bci = current_bci + tableswitch.default_offset();
1811 Block* block = analyzer->block_at(bci, jsrs);
1812 assert(_successors->length() == SWITCH_DEFAULT, "");
1813 _successors->append(block);
1814 while (--len >= 0) {
1815 int bci = current_bci + tableswitch.dest_offset_at(len);
1816 block = analyzer->block_at(bci, jsrs);
1817 assert(_successors->length() >= SWITCH_CASES, "");
1818 _successors->append_if_missing(block);
1819 }
1820 break;
1821 }
1822
1823 case Bytecodes::_lookupswitch: {
1824 Bytecode_lookupswitch lookupswitch(str);
1825
1826 int npairs = lookupswitch.number_of_pairs();
1827 _successors =
1828 new (arena) GrowableArray<Block*>(arena, npairs+1, 0, NULL);
1829 int bci = current_bci + lookupswitch.default_offset();
1830 Block* block = analyzer->block_at(bci, jsrs);
1831 assert(_successors->length() == SWITCH_DEFAULT, "");
1832 _successors->append(block);
1833 while(--npairs >= 0) {
1834 LookupswitchPair pair = lookupswitch.pair_at(npairs);
1835 int bci = current_bci + pair.offset();
1836 Block* block = analyzer->block_at(bci, jsrs);
1837 assert(_successors->length() >= SWITCH_CASES, "");
1838 _successors->append_if_missing(block);
1839 }
1840 break;
1841 }
1842
1843 case Bytecodes::_athrow:
1844 case Bytecodes::_ireturn:
1845 case Bytecodes::_lreturn:
1846 case Bytecodes::_freturn:
1847 case Bytecodes::_dreturn:
1848 case Bytecodes::_areturn:
1849 case Bytecodes::_return:
1850 _successors =
1851 new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1852 // No successors
1853 break;
1854
1855 case Bytecodes::_ret: {
1856 _successors =
1857 new (arena) GrowableArray<Block*>(arena, 1, 0, NULL);
1858
1859 Cell local = state->local(str->get_index());
1860 ciType* return_address = state->type_at(local);
1861 assert(return_address->is_return_address(), "verify: wrong type");
1862 int bci = return_address->as_return_address()->bci();
1863 assert(_successors->length() == GOTO_TARGET, "");
1864 _successors->append(analyzer->block_at(bci, jsrs));
1865 break;
1866 }
1867
1868 case Bytecodes::_wide:
1869 default:
1870 ShouldNotReachHere();
1871 break;
1872 }
1873 }
1874
1875 // Set predecessor information
1876 for (int i = 0; i < _successors->length(); i++) {
1877 Block* block = _successors->at(i);
1878 block->predecessors()->append(this);
1879 }
1880 }
1881 return _successors;
1882 }
1883
1884 // ------------------------------------------------------------------
1885 // ciTypeFlow::Block:compute_exceptions
1886 //
1887 // Compute the exceptional successors and types for this Block.
1888 void ciTypeFlow::Block::compute_exceptions() {
1889 assert(_exceptions == NULL && _exc_klasses == NULL, "repeat");
1890
1891 if (CITraceTypeFlow) {
1892 tty->print(">> Computing exceptions for block ");
1893 print_value_on(tty);
1894 tty->cr();
1895 }
1896
1897 ciTypeFlow* analyzer = outer();
1898 Arena* arena = analyzer->arena();
1899
1900 // Any bci in the block will do.
1901 ciExceptionHandlerStream str(analyzer->method(), start());
1902
1903 // Allocate our growable arrays.
1904 int exc_count = str.count();
1905 _exceptions = new (arena) GrowableArray<Block*>(arena, exc_count, 0, NULL);
1906 _exc_klasses = new (arena) GrowableArray<ciInstanceKlass*>(arena, exc_count,
1907 0, NULL);
1908
1909 for ( ; !str.is_done(); str.next()) {
1910 ciExceptionHandler* handler = str.handler();
1911 int bci = handler->handler_bci();
1912 ciInstanceKlass* klass = NULL;
1913 if (bci == -1) {
1914 // There is no catch all. It is possible to exit the method.
1915 break;
1916 }
1917 if (handler->is_catch_all()) {
1918 klass = analyzer->env()->Throwable_klass();
1919 } else {
1920 klass = handler->catch_klass();
1921 }
1922 Block* block = analyzer->block_at(bci, _jsrs);
1923 _exceptions->append(block);
1924 block->predecessors()->append(this);
1925 _exc_klasses->append(klass);
1926 }
1927 }
1928
1929 // ------------------------------------------------------------------
1930 // ciTypeFlow::Block::set_backedge_copy
1931 // Use this only to make a pre-existing public block into a backedge copy.
1932 void ciTypeFlow::Block::set_backedge_copy(bool z) {
1933 assert(z || (z == is_backedge_copy()), "cannot make a backedge copy public");
1934 _backedge_copy = z;
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 NULL;
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_irreducible_entry()) st->print(" irred");
1982 if (_jsrs->size() > 0) { st->print("/"); _jsrs->print_on(st); }
1983 if (is_backedge_copy()) st->print("/backedge_copy");
1984 }
1985
1986 // ------------------------------------------------------------------
1987 // ciTypeFlow::Block::print_on
1988 void ciTypeFlow::Block::print_on(outputStream* st) const {
1989 if ((Verbose || WizardMode) && (limit() >= 0)) {
1990 // Don't print 'dummy' blocks (i.e. blocks with limit() '-1')
1991 outer()->method()->print_codes_on(start(), limit(), st);
1992 }
1993 st->print_cr(" ==================================================== ");
1994 st->print (" ");
1995 print_value_on(st);
1996 st->print(" Stored locals: "); def_locals()->print_on(st, outer()->method()->max_locals()); tty->cr();
1997 if (loop() && loop()->parent() != NULL) {
1998 st->print(" loops:");
1999 Loop* lp = loop();
2000 do {
2001 st->print(" %d<-%d", lp->head()->pre_order(),lp->tail()->pre_order());
2002 if (lp->is_irreducible()) st->print("(ir)");
2003 lp = lp->parent();
2004 } while (lp->parent() != NULL);
2005 }
2006 st->cr();
2007 _state->print_on(st);
2008 if (_successors == NULL) {
2009 st->print_cr(" No successor information");
2010 } else {
2011 int num_successors = _successors->length();
2012 st->print_cr(" Successors : %d", num_successors);
2013 for (int i = 0; i < num_successors; i++) {
2014 Block* successor = _successors->at(i);
2015 st->print(" ");
2016 successor->print_value_on(st);
2017 st->cr();
2018 }
2019 }
2020 if (_predecessors == NULL) {
2021 st->print_cr(" No predecessor information");
2022 } else {
2023 int num_predecessors = _predecessors->length();
2024 st->print_cr(" Predecessors : %d", num_predecessors);
2025 for (int i = 0; i < num_predecessors; i++) {
2026 Block* predecessor = _predecessors->at(i);
2027 st->print(" ");
2028 predecessor->print_value_on(st);
2029 st->cr();
2030 }
2031 }
2032 if (_exceptions == NULL) {
2033 st->print_cr(" No exception information");
2034 } else {
2035 int num_exceptions = _exceptions->length();
2036 st->print_cr(" Exceptions : %d", num_exceptions);
2037 for (int i = 0; i < num_exceptions; i++) {
2038 Block* exc_succ = _exceptions->at(i);
2039 ciInstanceKlass* exc_klass = _exc_klasses->at(i);
2040 st->print(" ");
2041 exc_succ->print_value_on(st);
2042 st->print(" -- ");
2043 exc_klass->name()->print_symbol_on(st);
2044 st->cr();
2045 }
2046 }
2047 if (has_trap()) {
2048 st->print_cr(" Traps on %d with trap index %d", trap_bci(), trap_index());
2049 }
2050 st->print_cr(" ==================================================== ");
2051 }
2052 #endif
2053
2054 #ifndef PRODUCT
2055 // ------------------------------------------------------------------
2056 // ciTypeFlow::LocalSet::print_on
2057 void ciTypeFlow::LocalSet::print_on(outputStream* st, int limit) const {
2058 st->print("{");
2059 for (int i = 0; i < max; i++) {
2060 if (test(i)) st->print(" %d", i);
2061 }
2062 if (limit > max) {
2063 st->print(" %d..%d ", max, limit);
2064 }
2065 st->print(" }");
2066 }
2067 #endif
2068
2069 // ciTypeFlow
2070 //
2071 // This is a pass over the bytecodes which computes the following:
2072 // basic block structure
2073 // interpreter type-states (a la the verifier)
2074
2075 // ------------------------------------------------------------------
2076 // ciTypeFlow::ciTypeFlow
2077 ciTypeFlow::ciTypeFlow(ciEnv* env, ciMethod* method, int osr_bci) {
2078 _env = env;
2079 _method = method;
2080 _methodBlocks = method->get_method_blocks();
2081 _max_locals = method->max_locals();
2082 _max_stack = method->max_stack();
2083 _code_size = method->code_size();
2084 _has_irreducible_entry = false;
2085 _osr_bci = osr_bci;
2086 _failure_reason = NULL;
2087 assert(0 <= start_bci() && start_bci() < code_size() , "correct osr_bci argument: 0 <= %d < %d", start_bci(), code_size());
2088 _work_list = NULL;
2089
2090 _ciblock_count = _methodBlocks->num_blocks();
2091 _idx_to_blocklist = NEW_ARENA_ARRAY(arena(), GrowableArray<Block*>*, _ciblock_count);
2092 for (int i = 0; i < _ciblock_count; i++) {
2093 _idx_to_blocklist[i] = NULL;
2094 }
2095 _block_map = NULL; // until all blocks are seen
2096 _jsr_count = 0;
2097 _jsr_records = NULL;
2098 }
2099
2100 // ------------------------------------------------------------------
2101 // ciTypeFlow::work_list_next
2102 //
2103 // Get the next basic block from our work list.
2104 ciTypeFlow::Block* ciTypeFlow::work_list_next() {
2105 assert(!work_list_empty(), "work list must not be empty");
2106 Block* next_block = _work_list;
2107 _work_list = next_block->next();
2108 next_block->set_next(NULL);
2109 next_block->set_on_work_list(false);
2110 return next_block;
2111 }
2112
2113 // ------------------------------------------------------------------
2114 // ciTypeFlow::add_to_work_list
2115 //
2116 // Add a basic block to our work list.
2117 // List is sorted by decreasing postorder sort (same as increasing RPO)
2118 void ciTypeFlow::add_to_work_list(ciTypeFlow::Block* block) {
2119 assert(!block->is_on_work_list(), "must not already be on work list");
2120
2121 if (CITraceTypeFlow) {
2122 tty->print(">> Adding block ");
2123 block->print_value_on(tty);
2124 tty->print_cr(" to the work list : ");
2125 }
2126
2127 block->set_on_work_list(true);
2128
2129 // decreasing post order sort
2130
2131 Block* prev = NULL;
2132 Block* current = _work_list;
2133 int po = block->post_order();
2134 while (current != NULL) {
2135 if (!current->has_post_order() || po > current->post_order())
2136 break;
2137 prev = current;
2138 current = current->next();
2139 }
2140 if (prev == NULL) {
2141 block->set_next(_work_list);
2142 _work_list = block;
2143 } else {
2144 block->set_next(current);
2145 prev->set_next(block);
2146 }
2147
2148 if (CITraceTypeFlow) {
2149 tty->cr();
2150 }
2151 }
2152
2153 // ------------------------------------------------------------------
2154 // ciTypeFlow::block_at
2155 //
2156 // Return the block beginning at bci which has a JsrSet compatible
2157 // with jsrs.
2158 ciTypeFlow::Block* ciTypeFlow::block_at(int bci, ciTypeFlow::JsrSet* jsrs, CreateOption option) {
2159 // First find the right ciBlock.
2160 if (CITraceTypeFlow) {
2161 tty->print(">> Requesting block for %d/", bci);
2162 jsrs->print_on(tty);
2163 tty->cr();
2164 }
2165
2166 ciBlock* ciblk = _methodBlocks->block_containing(bci);
2167 assert(ciblk->start_bci() == bci, "bad ciBlock boundaries");
2168 Block* block = get_block_for(ciblk->index(), jsrs, option);
2169
2170 assert(block == NULL? (option == no_create): block->is_backedge_copy() == (option == create_backedge_copy), "create option consistent with result");
2171
2172 if (CITraceTypeFlow) {
2173 if (block != NULL) {
2174 tty->print(">> Found block ");
2175 block->print_value_on(tty);
2176 tty->cr();
2177 } else {
2178 tty->print_cr(">> No such block.");
2179 }
2180 }
2181
2182 return block;
2183 }
2184
2185 // ------------------------------------------------------------------
2186 // ciTypeFlow::make_jsr_record
2187 //
2188 // Make a JsrRecord for a given (entry, return) pair, if such a record
2189 // does not already exist.
2190 ciTypeFlow::JsrRecord* ciTypeFlow::make_jsr_record(int entry_address,
2191 int return_address) {
2192 if (_jsr_records == NULL) {
2193 _jsr_records = new (arena()) GrowableArray<JsrRecord*>(arena(),
2194 _jsr_count,
2195 0,
2196 NULL);
2197 }
2198 JsrRecord* record = NULL;
2199 int len = _jsr_records->length();
2200 for (int i = 0; i < len; i++) {
2201 JsrRecord* record = _jsr_records->at(i);
2202 if (record->entry_address() == entry_address &&
2203 record->return_address() == return_address) {
2204 return record;
2205 }
2206 }
2207
2208 record = new (arena()) JsrRecord(entry_address, return_address);
2209 _jsr_records->append(record);
2210 return record;
2211 }
2212
2213 // ------------------------------------------------------------------
2214 // ciTypeFlow::flow_exceptions
2215 //
2216 // Merge the current state into all exceptional successors at the
2217 // current point in the code.
2218 void ciTypeFlow::flow_exceptions(GrowableArray<ciTypeFlow::Block*>* exceptions,
2219 GrowableArray<ciInstanceKlass*>* exc_klasses,
2220 ciTypeFlow::StateVector* state) {
2221 int len = exceptions->length();
2222 assert(exc_klasses->length() == len, "must have same length");
2223 for (int i = 0; i < len; i++) {
2224 Block* block = exceptions->at(i);
2225 ciInstanceKlass* exception_klass = exc_klasses->at(i);
2226
2227 if (!exception_klass->is_loaded()) {
2228 // Do not compile any code for unloaded exception types.
2229 // Following compiler passes are responsible for doing this also.
2230 continue;
2231 }
2232
2233 if (block->meet_exception(exception_klass, state)) {
2234 // Block was modified and has PO. Add it to the work list.
2235 if (block->has_post_order() &&
2236 !block->is_on_work_list()) {
2237 add_to_work_list(block);
2238 }
2239 }
2240 }
2241 }
2242
2243 // ------------------------------------------------------------------
2244 // ciTypeFlow::flow_successors
2245 //
2246 // Merge the current state into all successors at the current point
2247 // in the code.
2248 void ciTypeFlow::flow_successors(GrowableArray<ciTypeFlow::Block*>* successors,
2249 ciTypeFlow::StateVector* state) {
2250 int len = successors->length();
2251 for (int i = 0; i < len; i++) {
2252 Block* block = successors->at(i);
2253 if (block->meet(state)) {
2254 // Block was modified and has PO. Add it to the work list.
2255 if (block->has_post_order() &&
2256 !block->is_on_work_list()) {
2257 add_to_work_list(block);
2258 }
2259 }
2260 }
2261 }
2262
2263 // ------------------------------------------------------------------
2264 // ciTypeFlow::can_trap
2265 //
2266 // Tells if a given instruction is able to generate an exception edge.
2267 bool ciTypeFlow::can_trap(ciBytecodeStream& str) {
2268 // Cf. GenerateOopMap::do_exception_edge.
2269 if (!Bytecodes::can_trap(str.cur_bc())) return false;
2270
2271 switch (str.cur_bc()) {
2272 // %%% FIXME: ldc of Class can generate an exception
2273 case Bytecodes::_ldc:
2274 case Bytecodes::_ldc_w:
2275 case Bytecodes::_ldc2_w:
2276 case Bytecodes::_aload_0:
2277 // These bytecodes can trap for rewriting. We need to assume that
2278 // they do not throw exceptions to make the monitor analysis work.
2279 return false;
2280
2281 case Bytecodes::_ireturn:
2282 case Bytecodes::_lreturn:
2283 case Bytecodes::_freturn:
2284 case Bytecodes::_dreturn:
2285 case Bytecodes::_areturn:
2286 case Bytecodes::_return:
2287 // We can assume the monitor stack is empty in this analysis.
2288 return false;
2289
2290 case Bytecodes::_monitorexit:
2291 // We can assume monitors are matched in this analysis.
2292 return false;
2293
2294 default:
2295 return true;
2296 }
2297 }
2298
2299 // ------------------------------------------------------------------
2300 // ciTypeFlow::clone_loop_heads
2301 //
2302 // Clone the loop heads
2303 bool ciTypeFlow::clone_loop_heads(Loop* lp, StateVector* temp_vector, JsrSet* temp_set) {
2304 bool rslt = false;
2305 for (PreorderLoops iter(loop_tree_root()); !iter.done(); iter.next()) {
2306 lp = iter.current();
2307 Block* head = lp->head();
2308 if (lp == loop_tree_root() ||
2309 lp->is_irreducible() ||
2310 !head->is_clonable_exit(lp))
2311 continue;
2312
2313 // Avoid BoxLock merge.
2314 if (EliminateNestedLocks && head->has_monitorenter())
2315 continue;
2316
2317 // check not already cloned
2318 if (head->backedge_copy_count() != 0)
2319 continue;
2320
2321 // Don't clone head of OSR loop to get correct types in start block.
2322 if (is_osr_flow() && head->start() == start_bci())
2323 continue;
2324
2325 // check _no_ shared head below us
2326 Loop* ch;
2327 for (ch = lp->child(); ch != NULL && ch->head() != head; ch = ch->sibling());
2328 if (ch != NULL)
2329 continue;
2330
2331 // Clone head
2332 Block* new_head = head->looping_succ(lp);
2333 Block* clone = clone_loop_head(lp, temp_vector, temp_set);
2334 // Update lp's info
2335 clone->set_loop(lp);
2336 lp->set_head(new_head);
2337 lp->set_tail(clone);
2338 // And move original head into outer loop
2339 head->set_loop(lp->parent());
2340
2341 rslt = true;
2342 }
2343 return rslt;
2344 }
2345
2346 // ------------------------------------------------------------------
2347 // ciTypeFlow::clone_loop_head
2348 //
2349 // Clone lp's head and replace tail's successors with clone.
2350 //
2351 // |
2352 // v
2353 // head <-> body
2354 // |
2355 // v
2356 // exit
2357 //
2358 // new_head
2359 //
2360 // |
2361 // v
2362 // head ----------\
2363 // | |
2364 // | v
2365 // | clone <-> body
2366 // | |
2367 // | /--/
2368 // | |
2369 // v v
2370 // exit
2371 //
2372 ciTypeFlow::Block* ciTypeFlow::clone_loop_head(Loop* lp, StateVector* temp_vector, JsrSet* temp_set) {
2373 Block* head = lp->head();
2374 Block* tail = lp->tail();
2375 if (CITraceTypeFlow) {
2376 tty->print(">> Requesting clone of loop head "); head->print_value_on(tty);
2377 tty->print(" for predecessor "); tail->print_value_on(tty);
2378 tty->cr();
2379 }
2380 Block* clone = block_at(head->start(), head->jsrs(), create_backedge_copy);
2381 assert(clone->backedge_copy_count() == 1, "one backedge copy for all back edges");
2382
2383 assert(!clone->has_pre_order(), "just created");
2384 clone->set_next_pre_order();
2385
2386 // Insert clone after (orig) tail in reverse post order
2387 clone->set_rpo_next(tail->rpo_next());
2388 tail->set_rpo_next(clone);
2389
2390 // tail->head becomes tail->clone
2391 for (SuccIter iter(tail); !iter.done(); iter.next()) {
2392 if (iter.succ() == head) {
2393 iter.set_succ(clone);
2394 // Update predecessor information
2395 head->predecessors()->remove(tail);
2396 clone->predecessors()->append(tail);
2397 }
2398 }
2399 flow_block(tail, temp_vector, temp_set);
2400 if (head == tail) {
2401 // For self-loops, clone->head becomes clone->clone
2402 flow_block(clone, temp_vector, temp_set);
2403 for (SuccIter iter(clone); !iter.done(); iter.next()) {
2404 if (iter.succ() == head) {
2405 iter.set_succ(clone);
2406 // Update predecessor information
2407 head->predecessors()->remove(clone);
2408 clone->predecessors()->append(clone);
2409 break;
2410 }
2411 }
2412 }
2413 flow_block(clone, temp_vector, temp_set);
2414
2415 return clone;
2416 }
2417
2418 // ------------------------------------------------------------------
2419 // ciTypeFlow::flow_block
2420 //
2421 // Interpret the effects of the bytecodes on the incoming state
2422 // vector of a basic block. Push the changed state to succeeding
2423 // basic blocks.
2424 void ciTypeFlow::flow_block(ciTypeFlow::Block* block,
2425 ciTypeFlow::StateVector* state,
2426 ciTypeFlow::JsrSet* jsrs) {
2427 if (CITraceTypeFlow) {
2428 tty->print("\n>> ANALYZING BLOCK : ");
2429 tty->cr();
2430 block->print_on(tty);
2431 }
2432 assert(block->has_pre_order(), "pre-order is assigned before 1st flow");
2433
2434 int start = block->start();
2435 int limit = block->limit();
2436 int control = block->control();
2437 if (control != ciBlock::fall_through_bci) {
2438 limit = control;
2439 }
2440
2441 // Grab the state from the current block.
2442 block->copy_state_into(state);
2443 state->def_locals()->clear();
2444
2445 GrowableArray<Block*>* exceptions = block->exceptions();
2446 GrowableArray<ciInstanceKlass*>* exc_klasses = block->exc_klasses();
2447 bool has_exceptions = exceptions->length() > 0;
2448
2449 bool exceptions_used = false;
2450
2451 ciBytecodeStream str(method());
2452 str.reset_to_bci(start);
2453 Bytecodes::Code code;
2454 while ((code = str.next()) != ciBytecodeStream::EOBC() &&
2455 str.cur_bci() < limit) {
2456 // Check for exceptional control flow from this point.
2457 if (has_exceptions && can_trap(str)) {
2458 flow_exceptions(exceptions, exc_klasses, state);
2459 exceptions_used = true;
2460 }
2461 // Apply the effects of the current bytecode to our state.
2462 bool res = state->apply_one_bytecode(&str);
2463
2464 // Watch for bailouts.
2465 if (failing()) return;
2466
2467 if (str.cur_bc() == Bytecodes::_monitorenter) {
2468 block->set_has_monitorenter();
2469 }
2470
2471 if (res) {
2472
2473 // We have encountered a trap. Record it in this block.
2474 block->set_trap(state->trap_bci(), state->trap_index());
2475
2476 if (CITraceTypeFlow) {
2477 tty->print_cr(">> Found trap");
2478 block->print_on(tty);
2479 }
2480
2481 // Save set of locals defined in this block
2482 block->def_locals()->add(state->def_locals());
2483
2484 // Record (no) successors.
2485 block->successors(&str, state, jsrs);
2486
2487 assert(!has_exceptions || exceptions_used, "Not removing exceptions");
2488
2489 // Discontinue interpretation of this Block.
2490 return;
2491 }
2492 }
2493
2494 GrowableArray<Block*>* successors = NULL;
2495 if (control != ciBlock::fall_through_bci) {
2496 // Check for exceptional control flow from this point.
2497 if (has_exceptions && can_trap(str)) {
2498 flow_exceptions(exceptions, exc_klasses, state);
2499 exceptions_used = true;
2500 }
2501
2502 // Fix the JsrSet to reflect effect of the bytecode.
2503 block->copy_jsrs_into(jsrs);
2504 jsrs->apply_control(this, &str, state);
2505
2506 // Find successor edges based on old state and new JsrSet.
2507 successors = block->successors(&str, state, jsrs);
2508
2509 // Apply the control changes to the state.
2510 state->apply_one_bytecode(&str);
2511 } else {
2512 // Fall through control
2513 successors = block->successors(&str, NULL, NULL);
2514 }
2515
2516 // Save set of locals defined in this block
2517 block->def_locals()->add(state->def_locals());
2518
2519 // Remove untaken exception paths
2520 if (!exceptions_used)
2521 exceptions->clear();
2522
2523 // Pass our state to successors.
2524 flow_successors(successors, state);
2525 }
2526
2527 // ------------------------------------------------------------------
2528 // ciTypeFlow::PreOrderLoops::next
2529 //
2530 // Advance to next loop tree using a preorder, left-to-right traversal.
2531 void ciTypeFlow::PreorderLoops::next() {
2532 assert(!done(), "must not be done.");
2533 if (_current->child() != NULL) {
2534 _current = _current->child();
2535 } else if (_current->sibling() != NULL) {
2536 _current = _current->sibling();
2537 } else {
2538 while (_current != _root && _current->sibling() == NULL) {
2539 _current = _current->parent();
2540 }
2541 if (_current == _root) {
2542 _current = NULL;
2543 assert(done(), "must be done.");
2544 } else {
2545 assert(_current->sibling() != NULL, "must be more to do");
2546 _current = _current->sibling();
2547 }
2548 }
2549 }
2550
2551 // ------------------------------------------------------------------
2552 // ciTypeFlow::Loop::sorted_merge
2553 //
2554 // Merge the branch lp into this branch, sorting on the loop head
2555 // pre_orders. Returns the leaf of the merged branch.
2556 // Child and sibling pointers will be setup later.
2557 // Sort is (looking from leaf towards the root)
2558 // descending on primary key: loop head's pre_order, and
2559 // ascending on secondary key: loop tail's pre_order.
2560 ciTypeFlow::Loop* ciTypeFlow::Loop::sorted_merge(Loop* lp) {
2561 Loop* leaf = this;
2562 Loop* prev = NULL;
2563 Loop* current = leaf;
2564 while (lp != NULL) {
2565 int lp_pre_order = lp->head()->pre_order();
2566 // Find insertion point for "lp"
2567 while (current != NULL) {
2568 if (current == lp)
2569 return leaf; // Already in list
2570 if (current->head()->pre_order() < lp_pre_order)
2571 break;
2572 if (current->head()->pre_order() == lp_pre_order &&
2573 current->tail()->pre_order() > lp->tail()->pre_order()) {
2574 break;
2575 }
2576 prev = current;
2577 current = current->parent();
2578 }
2579 Loop* next_lp = lp->parent(); // Save future list of items to insert
2580 // Insert lp before current
2581 lp->set_parent(current);
2582 if (prev != NULL) {
2583 prev->set_parent(lp);
2584 } else {
2585 leaf = lp;
2586 }
2587 prev = lp; // Inserted item is new prev[ious]
2588 lp = next_lp; // Next item to insert
2589 }
2590 return leaf;
2591 }
2592
2593 // ------------------------------------------------------------------
2594 // ciTypeFlow::build_loop_tree
2595 //
2596 // Incrementally build loop tree.
2597 void ciTypeFlow::build_loop_tree(Block* blk) {
2598 assert(!blk->is_post_visited(), "precondition");
2599 Loop* innermost = NULL; // merge of loop tree branches over all successors
2600
2601 for (SuccIter iter(blk); !iter.done(); iter.next()) {
2602 Loop* lp = NULL;
2603 Block* succ = iter.succ();
2604 if (!succ->is_post_visited()) {
2605 // Found backedge since predecessor post visited, but successor is not
2606 assert(succ->pre_order() <= blk->pre_order(), "should be backedge");
2607
2608 // Create a LoopNode to mark this loop.
2609 lp = new (arena()) Loop(succ, blk);
2610 if (succ->loop() == NULL)
2611 succ->set_loop(lp);
2612 // succ->loop will be updated to innermost loop on a later call, when blk==succ
2613
2614 } else { // Nested loop
2615 lp = succ->loop();
2616
2617 // If succ is loop head, find outer loop.
2618 while (lp != NULL && lp->head() == succ) {
2619 lp = lp->parent();
2620 }
2621 if (lp == NULL) {
2622 // Infinite loop, it's parent is the root
2623 lp = loop_tree_root();
2624 }
2625 }
2626
2627 // Check for irreducible loop.
2628 // Successor has already been visited. If the successor's loop head
2629 // has already been post-visited, then this is another entry into the loop.
2630 while (lp->head()->is_post_visited() && lp != loop_tree_root()) {
2631 _has_irreducible_entry = true;
2632 lp->set_irreducible(succ);
2633 if (!succ->is_on_work_list()) {
2634 // Assume irreducible entries need more data flow
2635 add_to_work_list(succ);
2636 }
2637 Loop* plp = lp->parent();
2638 if (plp == NULL) {
2639 // This only happens for some irreducible cases. The parent
2640 // will be updated during a later pass.
2641 break;
2642 }
2643 lp = plp;
2644 }
2645
2646 // Merge loop tree branch for all successors.
2647 innermost = innermost == NULL ? lp : innermost->sorted_merge(lp);
2648
2649 } // end loop
2650
2651 if (innermost == NULL) {
2652 assert(blk->successors()->length() == 0, "CFG exit");
2653 blk->set_loop(loop_tree_root());
2654 } else if (innermost->head() == blk) {
2655 // If loop header, complete the tree pointers
2656 if (blk->loop() != innermost) {
2657 #ifdef ASSERT
2658 assert(blk->loop()->head() == innermost->head(), "same head");
2659 Loop* dl;
2660 for (dl = innermost; dl != NULL && dl != blk->loop(); dl = dl->parent());
2661 assert(dl == blk->loop(), "blk->loop() already in innermost list");
2662 #endif
2663 blk->set_loop(innermost);
2664 }
2665 innermost->def_locals()->add(blk->def_locals());
2666 Loop* l = innermost;
2667 Loop* p = l->parent();
2668 while (p && l->head() == blk) {
2669 l->set_sibling(p->child()); // Put self on parents 'next child'
2670 p->set_child(l); // Make self the first child of parent
2671 p->def_locals()->add(l->def_locals());
2672 l = p; // Walk up the parent chain
2673 p = l->parent();
2674 }
2675 } else {
2676 blk->set_loop(innermost);
2677 innermost->def_locals()->add(blk->def_locals());
2678 }
2679 }
2680
2681 // ------------------------------------------------------------------
2682 // ciTypeFlow::Loop::contains
2683 //
2684 // Returns true if lp is nested loop.
2685 bool ciTypeFlow::Loop::contains(ciTypeFlow::Loop* lp) const {
2686 assert(lp != NULL, "");
2687 if (this == lp || head() == lp->head()) return true;
2688 int depth1 = depth();
2689 int depth2 = lp->depth();
2690 if (depth1 > depth2)
2691 return false;
2692 while (depth1 < depth2) {
2693 depth2--;
2694 lp = lp->parent();
2695 }
2696 return this == lp;
2697 }
2698
2699 // ------------------------------------------------------------------
2700 // ciTypeFlow::Loop::depth
2701 //
2702 // Loop depth
2703 int ciTypeFlow::Loop::depth() const {
2704 int dp = 0;
2705 for (Loop* lp = this->parent(); lp != NULL; lp = lp->parent())
2706 dp++;
2707 return dp;
2708 }
2709
2710 #ifndef PRODUCT
2711 // ------------------------------------------------------------------
2712 // ciTypeFlow::Loop::print
2713 void ciTypeFlow::Loop::print(outputStream* st, int indent) const {
2714 for (int i = 0; i < indent; i++) st->print(" ");
2715 st->print("%d<-%d %s",
2716 is_root() ? 0 : this->head()->pre_order(),
2717 is_root() ? 0 : this->tail()->pre_order(),
2718 is_irreducible()?" irr":"");
2719 st->print(" defs: ");
2720 def_locals()->print_on(st, _head->outer()->method()->max_locals());
2721 st->cr();
2722 for (Loop* ch = child(); ch != NULL; ch = ch->sibling())
2723 ch->print(st, indent+2);
2724 }
2725 #endif
2726
2727 // ------------------------------------------------------------------
2728 // ciTypeFlow::df_flow_types
2729 //
2730 // Perform the depth first type flow analysis. Helper for flow_types.
2731 void ciTypeFlow::df_flow_types(Block* start,
2732 bool do_flow,
2733 StateVector* temp_vector,
2734 JsrSet* temp_set) {
2735 int dft_len = 100;
2736 GrowableArray<Block*> stk(dft_len);
2737
2738 ciBlock* dummy = _methodBlocks->make_dummy_block();
2739 JsrSet* root_set = new JsrSet(NULL, 0);
2740 Block* root_head = new (arena()) Block(this, dummy, root_set);
2741 Block* root_tail = new (arena()) Block(this, dummy, root_set);
2742 root_head->set_pre_order(0);
2743 root_head->set_post_order(0);
2744 root_tail->set_pre_order(max_jint);
2745 root_tail->set_post_order(max_jint);
2746 set_loop_tree_root(new (arena()) Loop(root_head, root_tail));
2747
2748 stk.push(start);
2749
2750 _next_pre_order = 0; // initialize pre_order counter
2751 _rpo_list = NULL;
2752 int next_po = 0; // initialize post_order counter
2753
2754 // Compute RPO and the control flow graph
2755 int size;
2756 while ((size = stk.length()) > 0) {
2757 Block* blk = stk.top(); // Leave node on stack
2758 if (!blk->is_visited()) {
2759 // forward arc in graph
2760 assert (!blk->has_pre_order(), "");
2761 blk->set_next_pre_order();
2762
2763 if (_next_pre_order >= (int)Compile::current()->max_node_limit() / 2) {
2764 // Too many basic blocks. Bail out.
2765 // This can happen when try/finally constructs are nested to depth N,
2766 // and there is O(2**N) cloning of jsr bodies. See bug 4697245!
2767 // "MaxNodeLimit / 2" is used because probably the parser will
2768 // generate at least twice that many nodes and bail out.
2769 record_failure("too many basic blocks");
2770 return;
2771 }
2772 if (do_flow) {
2773 flow_block(blk, temp_vector, temp_set);
2774 if (failing()) return; // Watch for bailouts.
2775 }
2776 } else if (!blk->is_post_visited()) {
2777 // cross or back arc
2778 for (SuccIter iter(blk); !iter.done(); iter.next()) {
2779 Block* succ = iter.succ();
2780 if (!succ->is_visited()) {
2781 stk.push(succ);
2782 }
2783 }
2784 if (stk.length() == size) {
2785 // There were no additional children, post visit node now
2786 stk.pop(); // Remove node from stack
2787
2788 build_loop_tree(blk);
2789 blk->set_post_order(next_po++); // Assign post order
2790 prepend_to_rpo_list(blk);
2791 assert(blk->is_post_visited(), "");
2792
2793 if (blk->is_loop_head() && !blk->is_on_work_list()) {
2794 // Assume loop heads need more data flow
2795 add_to_work_list(blk);
2796 }
2797 }
2798 } else {
2799 stk.pop(); // Remove post-visited node from stack
2800 }
2801 }
2802 }
2803
2804 // ------------------------------------------------------------------
2805 // ciTypeFlow::flow_types
2806 //
2807 // Perform the type flow analysis, creating and cloning Blocks as
2808 // necessary.
2809 void ciTypeFlow::flow_types() {
2810 ResourceMark rm;
2811 StateVector* temp_vector = new StateVector(this);
2812 JsrSet* temp_set = new JsrSet(NULL, 16);
2813
2814 // Create the method entry block.
2815 Block* start = block_at(start_bci(), temp_set);
2816
2817 // Load the initial state into it.
2818 const StateVector* start_state = get_start_state();
2819 if (failing()) return;
2820 start->meet(start_state);
2821
2822 // Depth first visit
2823 df_flow_types(start, true /*do flow*/, temp_vector, temp_set);
2824
2825 if (failing()) return;
2826 assert(_rpo_list == start, "must be start");
2827
2828 // Any loops found?
2829 if (loop_tree_root()->child() != NULL &&
2830 env()->comp_level() >= CompLevel_full_optimization) {
2831 // Loop optimizations are not performed on Tier1 compiles.
2832
2833 bool changed = clone_loop_heads(loop_tree_root(), temp_vector, temp_set);
2834
2835 // If some loop heads were cloned, recompute postorder and loop tree
2836 if (changed) {
2837 loop_tree_root()->set_child(NULL);
2838 for (Block* blk = _rpo_list; blk != NULL;) {
2839 Block* next = blk->rpo_next();
2840 blk->df_init();
2841 blk = next;
2842 }
2843 df_flow_types(start, false /*no flow*/, temp_vector, temp_set);
2844 }
2845 }
2846
2847 if (CITraceTypeFlow) {
2848 tty->print_cr("\nLoop tree");
2849 loop_tree_root()->print();
2850 }
2851
2852 // Continue flow analysis until fixed point reached
2853
2854 debug_only(int max_block = _next_pre_order;)
2855
2856 while (!work_list_empty()) {
2857 Block* blk = work_list_next();
2858 assert (blk->has_post_order(), "post order assigned above");
2859
2860 flow_block(blk, temp_vector, temp_set);
2861
2862 assert (max_block == _next_pre_order, "no new blocks");
2863 assert (!failing(), "no more bailouts");
2864 }
2865 }
2866
2867 // ------------------------------------------------------------------
2868 // ciTypeFlow::map_blocks
2869 //
2870 // Create the block map, which indexes blocks in reverse post-order.
2871 void ciTypeFlow::map_blocks() {
2872 assert(_block_map == NULL, "single initialization");
2873 int block_ct = _next_pre_order;
2874 _block_map = NEW_ARENA_ARRAY(arena(), Block*, block_ct);
2875 assert(block_ct == block_count(), "");
2876
2877 Block* blk = _rpo_list;
2878 for (int m = 0; m < block_ct; m++) {
2879 int rpo = blk->rpo();
2880 assert(rpo == m, "should be sequential");
2881 _block_map[rpo] = blk;
2882 blk = blk->rpo_next();
2883 }
2884 assert(blk == NULL, "should be done");
2885
2886 for (int j = 0; j < block_ct; j++) {
2887 assert(_block_map[j] != NULL, "must not drop any blocks");
2888 Block* block = _block_map[j];
2889 // Remove dead blocks from successor lists:
2890 for (int e = 0; e <= 1; e++) {
2891 GrowableArray<Block*>* l = e? block->exceptions(): block->successors();
2892 for (int k = 0; k < l->length(); k++) {
2893 Block* s = l->at(k);
2894 if (!s->has_post_order()) {
2895 if (CITraceTypeFlow) {
2896 tty->print("Removing dead %s successor of #%d: ", (e? "exceptional": "normal"), block->pre_order());
2897 s->print_value_on(tty);
2898 tty->cr();
2899 }
2900 l->remove(s);
2901 --k;
2902 }
2903 }
2904 }
2905 }
2906 }
2907
2908 // ------------------------------------------------------------------
2909 // ciTypeFlow::get_block_for
2910 //
2911 // Find a block with this ciBlock which has a compatible JsrSet.
2912 // If no such block exists, create it, unless the option is no_create.
2913 // If the option is create_backedge_copy, always create a fresh backedge copy.
2914 ciTypeFlow::Block* ciTypeFlow::get_block_for(int ciBlockIndex, ciTypeFlow::JsrSet* jsrs, CreateOption option) {
2915 Arena* a = arena();
2916 GrowableArray<Block*>* blocks = _idx_to_blocklist[ciBlockIndex];
2917 if (blocks == NULL) {
2918 // Query only?
2919 if (option == no_create) return NULL;
2920
2921 // Allocate the growable array.
2922 blocks = new (a) GrowableArray<Block*>(a, 4, 0, NULL);
2923 _idx_to_blocklist[ciBlockIndex] = blocks;
2924 }
2925
2926 if (option != create_backedge_copy) {
2927 int len = blocks->length();
2928 for (int i = 0; i < len; i++) {
2929 Block* block = blocks->at(i);
2930 if (!block->is_backedge_copy() && block->is_compatible_with(jsrs)) {
2931 return block;
2932 }
2933 }
2934 }
2935
2936 // Query only?
2937 if (option == no_create) return NULL;
2938
2939 // We did not find a compatible block. Create one.
2940 Block* new_block = new (a) Block(this, _methodBlocks->block(ciBlockIndex), jsrs);
2941 if (option == create_backedge_copy) new_block->set_backedge_copy(true);
2942 blocks->append(new_block);
2943 return new_block;
2944 }
2945
2946 // ------------------------------------------------------------------
2947 // ciTypeFlow::backedge_copy_count
2948 //
2949 int ciTypeFlow::backedge_copy_count(int ciBlockIndex, ciTypeFlow::JsrSet* jsrs) const {
2950 GrowableArray<Block*>* blocks = _idx_to_blocklist[ciBlockIndex];
2951
2952 if (blocks == NULL) {
2953 return 0;
2954 }
2955
2956 int count = 0;
2957 int len = blocks->length();
2958 for (int i = 0; i < len; i++) {
2959 Block* block = blocks->at(i);
2960 if (block->is_backedge_copy() && block->is_compatible_with(jsrs)) {
2961 count++;
2962 }
2963 }
2964
2965 return count;
2966 }
2967
2968 // ------------------------------------------------------------------
2969 // ciTypeFlow::do_flow
2970 //
2971 // Perform type inference flow analysis.
2972 void ciTypeFlow::do_flow() {
2973 if (CITraceTypeFlow) {
2974 tty->print_cr("\nPerforming flow analysis on method");
2975 method()->print();
2976 if (is_osr_flow()) tty->print(" at OSR bci %d", start_bci());
2977 tty->cr();
2978 method()->print_codes();
2979 }
2980 if (CITraceTypeFlow) {
2981 tty->print_cr("Initial CI Blocks");
2982 print_on(tty);
2983 }
2984 flow_types();
2985 // Watch for bailouts.
2986 if (failing()) {
2987 return;
2988 }
2989
2990 map_blocks();
2991
2992 if (CIPrintTypeFlow || CITraceTypeFlow) {
2993 rpo_print_on(tty);
2994 }
2995 }
2996
2997 // ------------------------------------------------------------------
2998 // ciTypeFlow::is_dominated_by
2999 //
3000 // Determine if the instruction at bci is dominated by the instruction at dom_bci.
3001 bool ciTypeFlow::is_dominated_by(int bci, int dom_bci) {
3002 assert(!method()->has_jsrs(), "jsrs are not supported");
3003
3004 ResourceMark rm;
3005 JsrSet* jsrs = new ciTypeFlow::JsrSet(NULL);
3006 int index = _methodBlocks->block_containing(bci)->index();
3007 int dom_index = _methodBlocks->block_containing(dom_bci)->index();
3008 Block* block = get_block_for(index, jsrs, ciTypeFlow::no_create);
3009 Block* dom_block = get_block_for(dom_index, jsrs, ciTypeFlow::no_create);
3010
3011 // Start block dominates all other blocks
3012 if (start_block()->rpo() == dom_block->rpo()) {
3013 return true;
3014 }
3015
3016 // Dominated[i] is true if block i is dominated by dom_block
3017 int num_blocks = block_count();
3018 bool* dominated = NEW_RESOURCE_ARRAY(bool, num_blocks);
3019 for (int i = 0; i < num_blocks; ++i) {
3020 dominated[i] = true;
3021 }
3022 dominated[start_block()->rpo()] = false;
3023
3024 // Iterative dominator algorithm
3025 bool changed = true;
3026 while (changed) {
3027 changed = false;
3028 // Use reverse postorder iteration
3029 for (Block* blk = _rpo_list; blk != NULL; blk = blk->rpo_next()) {
3030 if (blk->is_start()) {
3031 // Ignore start block
3032 continue;
3033 }
3034 // The block is dominated if it is the dominating block
3035 // itself or if all predecessors are dominated.
3036 int index = blk->rpo();
3037 bool dom = (index == dom_block->rpo());
3038 if (!dom) {
3039 // Check if all predecessors are dominated
3040 dom = true;
3041 for (int i = 0; i < blk->predecessors()->length(); ++i) {
3042 Block* pred = blk->predecessors()->at(i);
3043 if (!dominated[pred->rpo()]) {
3044 dom = false;
3045 break;
3046 }
3047 }
3048 }
3049 // Update dominator information
3050 if (dominated[index] != dom) {
3051 changed = true;
3052 dominated[index] = dom;
3053 }
3054 }
3055 }
3056 // block dominated by dom_block?
3057 return dominated[block->rpo()];
3058 }
3059
3060 // ------------------------------------------------------------------
3061 // ciTypeFlow::record_failure()
3062 // The ciTypeFlow object keeps track of failure reasons separately from the ciEnv.
3063 // This is required because there is not a 1-1 relation between the ciEnv and
3064 // the TypeFlow passes within a compilation task. For example, if the compiler
3065 // is considering inlining a method, it will request a TypeFlow. If that fails,
3066 // the compilation as a whole may continue without the inlining. Some TypeFlow
3067 // requests are not optional; if they fail the requestor is responsible for
3068 // copying the failure reason up to the ciEnv. (See Parse::Parse.)
3069 void ciTypeFlow::record_failure(const char* reason) {
3070 if (env()->log() != NULL) {
3071 env()->log()->elem("failure reason='%s' phase='typeflow'", reason);
3072 }
3073 if (_failure_reason == NULL) {
3074 // Record the first failure reason.
3075 _failure_reason = reason;
3076 }
3077 }
3078
3079 ciType* ciTypeFlow::mark_as_never_null(ciType* type) {
3080 // Wrap the type to carry the information that it is never null
3081 return env()->make_never_null_wrapper(type);
3082 }
3083
3084 #ifndef PRODUCT
3085 // ------------------------------------------------------------------
3086 // ciTypeFlow::print_on
3087 void ciTypeFlow::print_on(outputStream* st) const {
3088 // Walk through CI blocks
3089 st->print_cr("********************************************************");
3090 st->print ("TypeFlow for ");
3091 method()->name()->print_symbol_on(st);
3092 int limit_bci = code_size();
3093 st->print_cr(" %d bytes", limit_bci);
3094 ciMethodBlocks *mblks = _methodBlocks;
3095 ciBlock* current = NULL;
3096 for (int bci = 0; bci < limit_bci; bci++) {
3097 ciBlock* blk = mblks->block_containing(bci);
3098 if (blk != NULL && blk != current) {
3099 current = blk;
3100 current->print_on(st);
3101
3102 GrowableArray<Block*>* blocks = _idx_to_blocklist[blk->index()];
3103 int num_blocks = (blocks == NULL) ? 0 : blocks->length();
3104
3105 if (num_blocks == 0) {
3106 st->print_cr(" No Blocks");
3107 } else {
3108 for (int i = 0; i < num_blocks; i++) {
3109 Block* block = blocks->at(i);
3110 block->print_on(st);
3111 }
3112 }
3113 st->print_cr("--------------------------------------------------------");
3114 st->cr();
3115 }
3116 }
3117 st->print_cr("********************************************************");
3118 st->cr();
3119 }
3120
3121 void ciTypeFlow::rpo_print_on(outputStream* st) const {
3122 st->print_cr("********************************************************");
3123 st->print ("TypeFlow for ");
3124 method()->name()->print_symbol_on(st);
3125 int limit_bci = code_size();
3126 st->print_cr(" %d bytes", limit_bci);
3127 for (Block* blk = _rpo_list; blk != NULL; blk = blk->rpo_next()) {
3128 blk->print_on(st);
3129 st->print_cr("--------------------------------------------------------");
3130 st->cr();
3131 }
3132 st->print_cr("********************************************************");
3133 st->cr();
3134 }
3135 #endif