1 /*
2 * Copyright (c) 1997, 2026, 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 "classfile/vmSymbols.hpp"
26 #include "interpreter/bytecodeStream.hpp"
27 #include "logging/log.hpp"
28 #include "logging/logStream.hpp"
29 #include "memory/allocation.inline.hpp"
30 #include "memory/resourceArea.hpp"
31 #include "oops/constantPool.hpp"
32 #include "oops/generateOopMap.hpp"
33 #include "oops/oop.inline.hpp"
34 #include "oops/symbol.hpp"
35 #include "runtime/handles.inline.hpp"
36 #include "runtime/java.hpp"
37 #include "runtime/os.hpp"
38 #include "runtime/relocator.hpp"
39 #include "runtime/timerTrace.hpp"
40 #include "utilities/bitMap.inline.hpp"
41 #include "utilities/ostream.hpp"
42
43 //
44 //
45 // Compute stack layouts for each instruction in method.
46 //
47 // Problems:
48 // - What to do about jsr with different types of local vars?
49 // Need maps that are conditional on jsr path?
50 // - Jsr and exceptions should be done more efficiently (the retAddr stuff)
51 //
52 // Alternative:
53 // - Could extend verifier to provide this information.
54 // For: one fewer abstract interpreter to maintain. Against: the verifier
55 // solves a bigger problem so slower (undesirable to force verification of
56 // everything?).
57 //
58 // Algorithm:
59 // Partition bytecodes into basic blocks
60 // For each basic block: store entry state (vars, stack). For instructions
61 // inside basic blocks we do not store any state (instead we recompute it
62 // from state produced by previous instruction).
63 //
64 // Perform abstract interpretation of bytecodes over this lattice:
65 //
66 // _--'#'--_
67 // / / \ \
68 // / / \ \
69 // / | | \
70 // 'r' 'v' 'p' ' '
71 // \ | | /
72 // \ \ / /
73 // \ \ / /
74 // -- '@' --
75 //
76 // '#' top, result of conflict merge
77 // 'r' reference type
78 // 'v' value type
79 // 'p' pc type for jsr/ret
80 // ' ' uninitialized; never occurs on operand stack in Java
81 // '@' bottom/unexecuted; initial state each bytecode.
82 //
83 // Basic block headers are the only merge points. We use this iteration to
84 // compute the information:
85 //
86 // find basic blocks;
87 // initialize them with uninitialized state;
88 // initialize first BB according to method signature;
89 // mark first BB changed
90 // while (some BB is changed) do {
91 // perform abstract interpration of all bytecodes in BB;
92 // merge exit state of BB into entry state of all successor BBs,
93 // noting if any of these change;
94 // }
95 //
96 // One additional complication is necessary. The jsr instruction pushes
97 // a return PC on the stack (a 'p' type in the abstract interpretation).
98 // To be able to process "ret" bytecodes, we keep track of these return
99 // PC's in a 'retAddrs' structure in abstract interpreter context (when
100 // processing a "ret" bytecodes, it is not sufficient to know that it gets
101 // an argument of the right type 'p'; we need to know which address it
102 // returns to).
103 //
104 // (Note this comment is borrowed form the original author of the algorithm)
105
106 // ComputeCallStack
107 //
108 // Specialization of SignatureIterator - compute the effects of a call
109 //
110 class ComputeCallStack : public SignatureIterator {
111 CellTypeState *_effect;
112 int _idx;
113
114 void setup();
115 void set(CellTypeState state) { _effect[_idx++] = state; }
116 int length() { return _idx; };
117
118 friend class SignatureIterator; // so do_parameters_on can call do_type
119 void do_type(BasicType type, bool for_return = false) {
120 if (for_return && type == T_VOID) {
121 set(CellTypeState::bottom);
122 } else if (is_reference_type(type)) {
123 set(CellTypeState::ref);
124 } else {
125 assert(is_java_primitive(type), "");
126 set(CellTypeState::value);
127 if (is_double_word_type(type)) {
128 set(CellTypeState::value);
129 }
130 }
131 }
132
133 public:
134 ComputeCallStack(Symbol* signature) : SignatureIterator(signature) {};
135
136 // Compute methods
137 int compute_for_parameters(bool is_static, CellTypeState *effect) {
138 _idx = 0;
139 _effect = effect;
140
141 if (!is_static) {
142 effect[_idx++] = CellTypeState::ref;
143 }
144
145 do_parameters_on(this);
146
147 return length();
148 };
149
150 int compute_for_returntype(CellTypeState *effect) {
151 _idx = 0;
152 _effect = effect;
153 do_type(return_type(), true);
154 set(CellTypeState::bottom); // Always terminate with a bottom state, so ppush works
155
156 return length();
157 }
158 };
159
160 //=========================================================================================
161 // ComputeEntryStack
162 //
163 // Specialization of SignatureIterator - in order to set up first stack frame
164 //
165 class ComputeEntryStack : public SignatureIterator {
166 CellTypeState *_effect;
167 int _idx;
168
169 void setup();
170 void set(CellTypeState state) { _effect[_idx++] = state; }
171 int length() { return _idx; };
172
173 friend class SignatureIterator; // so do_parameters_on can call do_type
174 void do_type(BasicType type, bool for_return = false) {
175 if (for_return && type == T_VOID) {
176 set(CellTypeState::bottom);
177 } else if (is_reference_type(type)) {
178 set(CellTypeState::make_slot_ref(_idx));
179 } else {
180 assert(is_java_primitive(type), "");
181 set(CellTypeState::value);
182 if (is_double_word_type(type)) {
183 set(CellTypeState::value);
184 }
185 }
186 }
187
188 public:
189 ComputeEntryStack(Symbol* signature) : SignatureIterator(signature) {};
190
191 // Compute methods
192 int compute_for_parameters(bool is_static, CellTypeState *effect) {
193 _idx = 0;
194 _effect = effect;
195
196 if (!is_static)
197 effect[_idx++] = CellTypeState::make_slot_ref(0);
198
199 do_parameters_on(this);
200
201 return length();
202 };
203
204 int compute_for_returntype(CellTypeState *effect) {
205 _idx = 0;
206 _effect = effect;
207 do_type(return_type(), true);
208 set(CellTypeState::bottom); // Always terminate with a bottom state, so ppush works
209
210 return length();
211 }
212 };
213
214 //=====================================================================================
215 //
216 // Implementation of RetTable/RetTableEntry
217 //
218 // Contains function to itereate through all bytecodes
219 // and find all return entry points
220 //
221 int RetTable::_init_nof_entries = 10;
222 int RetTableEntry::_init_nof_jsrs = 5;
223
224 RetTableEntry::RetTableEntry(int target, RetTableEntry *next) {
225 _target_bci = target;
226 _jsrs = new GrowableArray<int>(_init_nof_jsrs);
227 _next = next;
228 }
229
230 void RetTableEntry::add_delta(int bci, int delta) {
231 if (_target_bci > bci) _target_bci += delta;
232
233 for (int k = 0; k < _jsrs->length(); k++) {
234 int jsr = _jsrs->at(k);
235 if (jsr > bci) _jsrs->at_put(k, jsr+delta);
236 }
237 }
238
239 void RetTable::compute_ret_table(const methodHandle& method) {
240 BytecodeStream i(method);
241 Bytecodes::Code bytecode;
242
243 while( (bytecode = i.next()) >= 0) {
244 switch (bytecode) {
245 case Bytecodes::_jsr:
246 add_jsr(i.next_bci(), i.dest());
247 break;
248 case Bytecodes::_jsr_w:
249 add_jsr(i.next_bci(), i.dest_w());
250 break;
251 default:
252 break;
253 }
254 }
255 }
256
257 void RetTable::add_jsr(int return_bci, int target_bci) {
258 RetTableEntry* entry = _first;
259
260 // Scan table for entry
261 for (;entry && entry->target_bci() != target_bci; entry = entry->next());
262
263 if (!entry) {
264 // Allocate new entry and put in list
265 entry = new RetTableEntry(target_bci, _first);
266 _first = entry;
267 }
268
269 // Now "entry" is set. Make sure that the entry is initialized
270 // and has room for the new jsr.
271 entry->add_jsr(return_bci);
272 }
273
274 RetTableEntry* RetTable::find_jsrs_for_target(int targBci) {
275 RetTableEntry *cur = _first;
276
277 while(cur) {
278 assert(cur->target_bci() != -1, "sanity check");
279 if (cur->target_bci() == targBci) return cur;
280 cur = cur->next();
281 }
282 ShouldNotReachHere();
283 return nullptr;
284 }
285
286 // The instruction at bci is changing size by "delta". Update the return map.
287 void RetTable::update_ret_table(int bci, int delta) {
288 RetTableEntry *cur = _first;
289 while(cur) {
290 cur->add_delta(bci, delta);
291 cur = cur->next();
292 }
293 }
294
295 //
296 // Celltype state
297 //
298
299 CellTypeState CellTypeState::bottom = CellTypeState::make_bottom();
300 CellTypeState CellTypeState::uninit = CellTypeState::make_any(uninit_value);
301 CellTypeState CellTypeState::ref = CellTypeState::make_any(ref_conflict);
302 CellTypeState CellTypeState::value = CellTypeState::make_any(val_value);
303 CellTypeState CellTypeState::refUninit = CellTypeState::make_any(ref_conflict | uninit_value);
304 CellTypeState CellTypeState::top = CellTypeState::make_top();
305 CellTypeState CellTypeState::addr = CellTypeState::make_any(addr_conflict);
306
307 // Commonly used constants
308 static CellTypeState epsilonCTS[1] = { CellTypeState::bottom };
309 static CellTypeState refCTS = CellTypeState::ref;
310 static CellTypeState valCTS = CellTypeState::value;
311 static CellTypeState vCTS[2] = { CellTypeState::value, CellTypeState::bottom };
312 static CellTypeState rCTS[2] = { CellTypeState::ref, CellTypeState::bottom };
313 static CellTypeState rrCTS[3] = { CellTypeState::ref, CellTypeState::ref, CellTypeState::bottom };
314 static CellTypeState vrCTS[3] = { CellTypeState::value, CellTypeState::ref, CellTypeState::bottom };
315 static CellTypeState vvCTS[3] = { CellTypeState::value, CellTypeState::value, CellTypeState::bottom };
316 static CellTypeState rvrCTS[4] = { CellTypeState::ref, CellTypeState::value, CellTypeState::ref, CellTypeState::bottom };
317 static CellTypeState vvrCTS[4] = { CellTypeState::value, CellTypeState::value, CellTypeState::ref, CellTypeState::bottom };
318 static CellTypeState vvvCTS[4] = { CellTypeState::value, CellTypeState::value, CellTypeState::value, CellTypeState::bottom };
319 static CellTypeState vvvrCTS[5] = { CellTypeState::value, CellTypeState::value, CellTypeState::value, CellTypeState::ref, CellTypeState::bottom };
320 static CellTypeState vvvvCTS[5] = { CellTypeState::value, CellTypeState::value, CellTypeState::value, CellTypeState::value, CellTypeState::bottom };
321
322 char CellTypeState::to_char() const {
323 if (can_be_reference()) {
324 if (can_be_value() || can_be_address())
325 return '#'; // Conflict that needs to be rewritten
326 else
327 return 'r';
328 } else if (can_be_value())
329 return 'v';
330 else if (can_be_address())
331 return 'p';
332 else if (can_be_uninit())
333 return ' ';
334 else
335 return '@';
336 }
337
338
339 // Print a detailed CellTypeState. Indicate all bits that are set. If
340 // the CellTypeState represents an address or a reference, print the
341 // value of the additional information.
342 void CellTypeState::print(outputStream *os) {
343 if (can_be_address()) {
344 os->print("(p");
345 } else {
346 os->print("( ");
347 }
348 if (can_be_reference()) {
349 os->print("r");
350 } else {
351 os->print(" ");
352 }
353 if (can_be_value()) {
354 os->print("v");
355 } else {
356 os->print(" ");
357 }
358 if (can_be_uninit()) {
359 os->print("u|");
360 } else {
361 os->print(" |");
362 }
363 if (is_info_top()) {
364 os->print("Top)");
365 } else if (is_info_bottom()) {
366 os->print("Bot)");
367 } else {
368 if (is_reference()) {
369 int info = get_info();
370 int data = info & ~(ref_not_lock_bit | ref_slot_bit);
371 if (info & ref_not_lock_bit) {
372 // Not a monitor lock reference.
373 if (info & ref_slot_bit) {
374 // slot
375 os->print("slot%d)", data);
376 } else {
377 // line
378 os->print("line%d)", data);
379 }
380 } else {
381 // lock
382 os->print("lock%d)", data);
383 }
384 } else {
385 os->print("%d)", get_info());
386 }
387 }
388 }
389
390 //
391 // Basicblock handling methods
392 //
393
394 void GenerateOopMap::initialize_bb() {
395 _bb_count = 0;
396 _bb_hdr_bits.reinitialize(method()->code_size());
397 }
398
399 void GenerateOopMap::bb_mark_fct(GenerateOopMap *c, int bci, int *data) {
400 assert(bci>= 0 && bci < c->method()->code_size(), "index out of bounds");
401 if (c->is_bb_header(bci))
402 return;
403
404 log_debug(generateoopmap)( "Basicblock#%d begins at: %d", c->_bb_count, bci);
405 c->set_bbmark_bit(bci);
406 c->_bb_count++;
407 }
408
409
410 void GenerateOopMap::mark_bbheaders() {
411 initialize_bb();
412
413 bool fellThrough = false; // False to get first BB marked.
414
415 // First mark all exception handlers as start of a basic-block
416 ExceptionTable excps(method());
417 for(int i = 0; i < excps.length(); i ++) {
418 bb_mark_fct(this, excps.handler_pc(i), nullptr);
419 }
420
421 // Then iterate through the code
422 BytecodeStream bcs(_method);
423 Bytecodes::Code bytecode;
424
425 while( (bytecode = bcs.next()) >= 0) {
426 int bci = bcs.bci();
427
428 if (!fellThrough)
429 bb_mark_fct(this, bci, nullptr);
430
431 fellThrough = jump_targets_do(&bcs, &GenerateOopMap::bb_mark_fct, nullptr);
432
433 /* We will also mark successors of jsr's as basic block headers. */
434 switch (bytecode) {
435 case Bytecodes::_jsr:
436 case Bytecodes::_jsr_w:
437 assert(!fellThrough, "should not happen");
438 // If this is the last bytecode, there is no successor to mark
439 if (bci + Bytecodes::length_for(bytecode) < method()->code_size()) {
440 bb_mark_fct(this, bci + Bytecodes::length_for(bytecode), nullptr);
441 }
442 break;
443 default:
444 break;
445 }
446 }
447 }
448
449 void GenerateOopMap::set_bbmark_bit(int bci) {
450 _bb_hdr_bits.at_put(bci, true);
451 }
452
453 void GenerateOopMap::reachable_basicblock(GenerateOopMap *c, int bci, int *data) {
454 assert(bci>= 0 && bci < c->method()->code_size(), "index out of bounds");
455 BasicBlock* bb = c->get_basic_block_at(bci);
456 if (bb->is_dead()) {
457 bb->mark_as_alive();
458 *data = 1; // Mark basicblock as changed
459 }
460 }
461
462
463 void GenerateOopMap::mark_reachable_code() {
464 int change = 1; // int to get function pointers to work
465
466 // Mark entry basic block as alive and all exception handlers
467 _basic_blocks[0].mark_as_alive();
468 ExceptionTable excps(method());
469 for(int i = 0; i < excps.length(); i++) {
470 BasicBlock *bb = get_basic_block_at(excps.handler_pc(i));
471 // If block is not already alive (due to multiple exception handlers to same bb), then
472 // make it alive
473 if (bb->is_dead()) bb->mark_as_alive();
474 }
475
476 BytecodeStream bcs(_method);
477
478 // Iterate through all basic blocks until we reach a fixpoint
479 while (change) {
480 change = 0;
481
482 for (int i = 0; i < _bb_count; i++) {
483 BasicBlock *bb = &_basic_blocks[i];
484 if (bb->is_alive()) {
485 // Position bytecodestream at last bytecode in basicblock
486 bcs.set_start(bb->_end_bci);
487 bcs.next();
488 Bytecodes::Code bytecode = bcs.code();
489 int bci = bcs.bci();
490 assert(bci == bb->_end_bci, "wrong bci");
491
492 bool fell_through = jump_targets_do(&bcs, &GenerateOopMap::reachable_basicblock, &change);
493
494 // We will also mark successors of jsr's as alive.
495 switch (bytecode) {
496 case Bytecodes::_jsr:
497 case Bytecodes::_jsr_w:
498 assert(!fell_through, "should not happen");
499 // If this is the last bytecode, there is no successor to mark
500 if (bci + Bytecodes::length_for(bytecode) < method()->code_size()) {
501 reachable_basicblock(this, bci + Bytecodes::length_for(bytecode), &change);
502 }
503 break;
504 default:
505 break;
506 }
507 if (fell_through) {
508 // Mark successor as alive
509 if (bb[1].is_dead()) {
510 bb[1].mark_as_alive();
511 change = 1;
512 }
513 }
514 }
515 }
516 }
517 }
518
519 /* If the current instruction in "c" has no effect on control flow,
520 returns "true". Otherwise, calls "jmpFct" one or more times, with
521 "c", an appropriate "pcDelta", and "data" as arguments, then
522 returns "false". There is one exception: if the current
523 instruction is a "ret", returns "false" without calling "jmpFct".
524 Arrangements for tracking the control flow of a "ret" must be made
525 externally. */
526 bool GenerateOopMap::jump_targets_do(BytecodeStream *bcs, jmpFct_t jmpFct, int *data) {
527 int bci = bcs->bci();
528
529 switch (bcs->code()) {
530 case Bytecodes::_ifeq:
531 case Bytecodes::_ifne:
532 case Bytecodes::_iflt:
533 case Bytecodes::_ifge:
534 case Bytecodes::_ifgt:
535 case Bytecodes::_ifle:
536 case Bytecodes::_if_icmpeq:
537 case Bytecodes::_if_icmpne:
538 case Bytecodes::_if_icmplt:
539 case Bytecodes::_if_icmpge:
540 case Bytecodes::_if_icmpgt:
541 case Bytecodes::_if_icmple:
542 case Bytecodes::_if_acmpeq:
543 case Bytecodes::_if_acmpne:
544 case Bytecodes::_ifnull:
545 case Bytecodes::_ifnonnull:
546 (*jmpFct)(this, bcs->dest(), data);
547 // Class files verified by the old verifier can have a conditional branch
548 // as their last bytecode, provided the conditional branch is unreachable
549 // during execution. Check if this instruction is the method's last bytecode
550 // and, if so, don't call the jmpFct.
551 if (bci + 3 < method()->code_size()) {
552 (*jmpFct)(this, bci + 3, data);
553 }
554 break;
555
556 case Bytecodes::_goto:
557 (*jmpFct)(this, bcs->dest(), data);
558 break;
559 case Bytecodes::_goto_w:
560 (*jmpFct)(this, bcs->dest_w(), data);
561 break;
562 case Bytecodes::_tableswitch:
563 { Bytecode_tableswitch tableswitch(method(), bcs->bcp());
564 int len = tableswitch.length();
565
566 (*jmpFct)(this, bci + tableswitch.default_offset(), data); /* Default. jump address */
567 while (--len >= 0) {
568 (*jmpFct)(this, bci + tableswitch.dest_offset_at(len), data);
569 }
570 break;
571 }
572
573 case Bytecodes::_lookupswitch:
574 { Bytecode_lookupswitch lookupswitch(method(), bcs->bcp());
575 int npairs = lookupswitch.number_of_pairs();
576 (*jmpFct)(this, bci + lookupswitch.default_offset(), data); /* Default. */
577 while(--npairs >= 0) {
578 LookupswitchPair pair = lookupswitch.pair_at(npairs);
579 (*jmpFct)(this, bci + pair.offset(), data);
580 }
581 break;
582 }
583 case Bytecodes::_jsr:
584 assert(bcs->is_wide()==false, "sanity check");
585 (*jmpFct)(this, bcs->dest(), data);
586 break;
587 case Bytecodes::_jsr_w:
588 (*jmpFct)(this, bcs->dest_w(), data);
589 break;
590 case Bytecodes::_wide:
591 ShouldNotReachHere();
592 return true;
593 break;
594 case Bytecodes::_athrow:
595 case Bytecodes::_ireturn:
596 case Bytecodes::_lreturn:
597 case Bytecodes::_freturn:
598 case Bytecodes::_dreturn:
599 case Bytecodes::_areturn:
600 case Bytecodes::_return:
601 case Bytecodes::_ret:
602 break;
603 default:
604 return true;
605 }
606 return false;
607 }
608
609 /* Requires "pc" to be the head of a basic block; returns that basic
610 block. */
611 BasicBlock *GenerateOopMap::get_basic_block_at(int bci) const {
612 BasicBlock* bb = get_basic_block_containing(bci);
613 assert(bb->_bci == bci, "should have found BB");
614 return bb;
615 }
616
617 // Requires "pc" to be the start of an instruction; returns the basic
618 // block containing that instruction. */
619 BasicBlock *GenerateOopMap::get_basic_block_containing(int bci) const {
620 BasicBlock *bbs = _basic_blocks;
621 int lo = 0, hi = _bb_count - 1;
622
623 while (lo <= hi) {
624 int m = (lo + hi) / 2;
625 int mbci = bbs[m]._bci;
626 int nbci;
627
628 if ( m == _bb_count-1) {
629 assert( bci >= mbci && bci < method()->code_size(), "sanity check failed");
630 return bbs+m;
631 } else {
632 nbci = bbs[m+1]._bci;
633 }
634
635 if ( mbci <= bci && bci < nbci) {
636 return bbs+m;
637 } else if (mbci < bci) {
638 lo = m + 1;
639 } else {
640 assert(mbci > bci, "sanity check");
641 hi = m - 1;
642 }
643 }
644
645 fatal("should have found BB");
646 return nullptr;
647 }
648
649 void GenerateOopMap::restore_state(BasicBlock *bb)
650 {
651 memcpy(_state, bb->_state, _state_len*sizeof(CellTypeState));
652 _stack_top = bb->_stack_top;
653 _monitor_top = bb->_monitor_top;
654 }
655
656 int GenerateOopMap::next_bb_start_pc(BasicBlock *bb) {
657 intptr_t bbNum = bb - _basic_blocks + 1;
658 if (bbNum == _bb_count)
659 return method()->code_size();
660
661 return _basic_blocks[bbNum]._bci;
662 }
663
664 //
665 // CellType handling methods
666 //
667
668 // Allocate memory and throw LinkageError if failure.
669 #define ALLOC_RESOURCE_ARRAY(var, type, count) \
670 var = NEW_RESOURCE_ARRAY_RETURN_NULL(type, count); \
671 if (var == nullptr) { \
672 report_error("Cannot reserve enough memory to analyze this method"); \
673 return; \
674 }
675
676
677 void GenerateOopMap::init_state() {
678 _state_len = _max_locals + _max_stack + _max_monitors;
679 ALLOC_RESOURCE_ARRAY(_state, CellTypeState, _state_len);
680 memset(_state, 0, _state_len * sizeof(CellTypeState));
681 int count = MAX3(_max_locals, _max_stack, _max_monitors) + 1/*for null terminator char */;
682 ALLOC_RESOURCE_ARRAY(_state_vec_buf, char, count);
683 }
684
685 void GenerateOopMap::make_context_uninitialized() {
686 CellTypeState* vs = vars();
687
688 for (int i = 0; i < _max_locals; i++)
689 vs[i] = CellTypeState::uninit;
690
691 _stack_top = 0;
692 _monitor_top = 0;
693 }
694
695 int GenerateOopMap::methodsig_to_effect(Symbol* signature, bool is_static, CellTypeState* effect) {
696 ComputeEntryStack ces(signature);
697 return ces.compute_for_parameters(is_static, effect);
698 }
699
700 // Return result of merging cts1 and cts2.
701 CellTypeState CellTypeState::merge(CellTypeState cts, int slot) const {
702 CellTypeState result;
703
704 assert(!is_bottom() && !cts.is_bottom(),
705 "merge of bottom values is handled elsewhere");
706
707 result._state = _state | cts._state;
708
709 // If the top bit is set, we don't need to do any more work.
710 if (!result.is_info_top()) {
711 assert((result.can_be_address() || result.can_be_reference()),
712 "only addresses and references have non-top info");
713
714 if (!equal(cts)) {
715 // The two values being merged are different. Raise to top.
716 if (result.is_reference()) {
717 result = CellTypeState::make_slot_ref(slot);
718 } else {
719 result._state |= info_conflict;
720 }
721 }
722 }
723 assert(result.is_valid_state(), "checking that CTS merge maintains legal state");
724
725 return result;
726 }
727
728 // Merge the variable state for locals and stack from cts into bbts.
729 bool GenerateOopMap::merge_local_state_vectors(CellTypeState* cts,
730 CellTypeState* bbts) {
731 int i;
732 int len = _max_locals + _stack_top;
733 bool change = false;
734
735 for (i = len - 1; i >= 0; i--) {
736 CellTypeState v = cts[i].merge(bbts[i], i);
737 change = change || !v.equal(bbts[i]);
738 bbts[i] = v;
739 }
740
741 return change;
742 }
743
744 // Merge the monitor stack state from cts into bbts.
745 bool GenerateOopMap::merge_monitor_state_vectors(CellTypeState* cts,
746 CellTypeState* bbts) {
747 bool change = false;
748 if (_max_monitors > 0 && _monitor_top != bad_monitors) {
749 // If there are no monitors in the program, or there has been
750 // a monitor matching error before this point in the program,
751 // then we do not merge in the monitor state.
752
753 int base = _max_locals + _max_stack;
754 int len = base + _monitor_top;
755 for (int i = len - 1; i >= base; i--) {
756 CellTypeState v = cts[i].merge(bbts[i], i);
757
758 // Can we prove that, when there has been a change, it will already
759 // have been detected at this point? That would make this equal
760 // check here unnecessary.
761 change = change || !v.equal(bbts[i]);
762 bbts[i] = v;
763 }
764 }
765
766 return change;
767 }
768
769 void GenerateOopMap::copy_state(CellTypeState *dst, CellTypeState *src) {
770 int len = _max_locals + _stack_top;
771 for (int i = 0; i < len; i++) {
772 if (src[i].is_nonlock_reference()) {
773 dst[i] = CellTypeState::make_slot_ref(i);
774 } else {
775 dst[i] = src[i];
776 }
777 }
778 if (_max_monitors > 0 && _monitor_top != bad_monitors) {
779 int base = _max_locals + _max_stack;
780 len = base + _monitor_top;
781 for (int i = base; i < len; i++) {
782 dst[i] = src[i];
783 }
784 }
785 }
786
787
788 // Merge the states for the current block and the next. As long as a
789 // block is reachable the locals and stack must be merged. If the
790 // stack heights don't match then this is a verification error and
791 // it's impossible to interpret the code. Simultaneously monitor
792 // states are being check to see if they nest statically. If monitor
793 // depths match up then their states are merged. Otherwise the
794 // mismatch is simply recorded and interpretation continues since
795 // monitor matching is purely informational and doesn't say anything
796 // about the correctness of the code.
797 void GenerateOopMap::merge_state_into_bb(BasicBlock *bb) {
798 guarantee(bb != nullptr, "null basicblock");
799 assert(bb->is_alive(), "merging state into a dead basicblock");
800
801 if (_stack_top == bb->_stack_top) {
802 // always merge local state even if monitors don't match.
803 if (merge_local_state_vectors(_state, bb->_state)) {
804 bb->set_changed(true);
805 }
806 if (_monitor_top == bb->_monitor_top) {
807 // monitors still match so continue merging monitor states.
808 if (merge_monitor_state_vectors(_state, bb->_state)) {
809 bb->set_changed(true);
810 }
811 } else {
812 if (log_is_enabled(Info, monitormismatch)) {
813 report_monitor_mismatch("monitor stack height merge conflict");
814 }
815 // When the monitor stacks are not matched, we set _monitor_top to
816 // bad_monitors. This signals that, from here on, the monitor stack cannot
817 // be trusted. In particular, monitorexit bytecodes may throw
818 // exceptions. We mark this block as changed so that the change
819 // propagates properly.
820 bb->_monitor_top = bad_monitors;
821 bb->set_changed(true);
822 _monitor_safe = false;
823 }
824 } else if (!bb->is_reachable()) {
825 // First time we look at this BB
826 copy_state(bb->_state, _state);
827 bb->_stack_top = _stack_top;
828 bb->_monitor_top = _monitor_top;
829 bb->set_changed(true);
830 } else {
831 verify_error("stack height conflict: %d vs. %d", _stack_top, bb->_stack_top);
832 }
833 }
834
835 void GenerateOopMap::merge_state(GenerateOopMap *gom, int bci, int* data) {
836 gom->merge_state_into_bb(gom->get_basic_block_at(bci));
837 }
838
839 void GenerateOopMap::set_var(int localNo, CellTypeState cts) {
840 assert(cts.is_reference() || cts.is_value() || cts.is_address(),
841 "wrong celltypestate");
842 if (localNo < 0 || localNo > _max_locals) {
843 verify_error("variable write error: r%d", localNo);
844 return;
845 }
846 vars()[localNo] = cts;
847 }
848
849 CellTypeState GenerateOopMap::get_var(int localNo) {
850 assert(localNo < _max_locals + _nof_refval_conflicts, "variable read error");
851 if (localNo < 0 || localNo > _max_locals) {
852 verify_error("variable read error: r%d", localNo);
853 return valCTS; // just to pick something;
854 }
855 return vars()[localNo];
856 }
857
858 CellTypeState GenerateOopMap::pop() {
859 if ( _stack_top <= 0) {
860 verify_error("stack underflow");
861 return valCTS; // just to pick something
862 }
863 return stack()[--_stack_top];
864 }
865
866 void GenerateOopMap::push(CellTypeState cts) {
867 if ( _stack_top >= _max_stack) {
868 verify_error("stack overflow");
869 return;
870 }
871 stack()[_stack_top++] = cts;
872 }
873
874 CellTypeState GenerateOopMap::monitor_pop() {
875 assert(_monitor_top != bad_monitors, "monitor_pop called on error monitor stack");
876 if (_monitor_top == 0) {
877 // We have detected a pop of an empty monitor stack.
878 _monitor_safe = false;
879 _monitor_top = bad_monitors;
880
881 if (log_is_enabled(Info, monitormismatch)) {
882 report_monitor_mismatch("monitor stack underflow");
883 }
884 return CellTypeState::ref; // just to keep the analysis going.
885 }
886 return monitors()[--_monitor_top];
887 }
888
889 void GenerateOopMap::monitor_push(CellTypeState cts) {
890 assert(_monitor_top != bad_monitors, "monitor_push called on error monitor stack");
891 if (_monitor_top >= _max_monitors) {
892 // Some monitorenter is being executed more than once.
893 // This means that the monitor stack cannot be simulated.
894 _monitor_safe = false;
895 _monitor_top = bad_monitors;
896
897 if (log_is_enabled(Info, monitormismatch)) {
898 report_monitor_mismatch("monitor stack overflow");
899 }
900 return;
901 }
902 monitors()[_monitor_top++] = cts;
903 }
904
905 //
906 // Interpretation handling methods
907 //
908
909 void GenerateOopMap::do_interpretation()
910 {
911 // "i" is just for debugging, so we can detect cases where this loop is
912 // iterated more than once.
913 int i = 0;
914 do {
915 if (log_is_enabled(Trace, generateoopmap)) {
916 LogStream st(Log(generateoopmap)::trace());
917 st.print("Iteration #%d of do_interpretation loop, method:", i);
918 method()->print_name(&st);
919 st.print("\n\n");
920 }
921 _conflict = false;
922 _monitor_safe = true;
923 // init_state is now called from init_basic_blocks. The length of a
924 // state vector cannot be determined until we have made a pass through
925 // the bytecodes counting the possible monitor entries.
926 if (!_got_error) init_basic_blocks();
927 if (!_got_error) setup_method_entry_state();
928 if (!_got_error) interp_all();
929 if (!_got_error) rewrite_refval_conflicts();
930 i++;
931 } while (_conflict && !_got_error);
932 }
933
934 void GenerateOopMap::init_basic_blocks() {
935 // Note: Could consider reserving only the needed space for each BB's state
936 // (entry stack may not be of maximal height for every basic block).
937 // But cumbersome since we don't know the stack heights yet. (Nor the
938 // monitor stack heights...)
939
940 ALLOC_RESOURCE_ARRAY(_basic_blocks, BasicBlock, _bb_count);
941
942 // Make a pass through the bytecodes. Count the number of monitorenters.
943 // This can be used an upper bound on the monitor stack depth in programs
944 // which obey stack discipline with their monitor usage. Initialize the
945 // known information about basic blocks.
946 BytecodeStream j(_method);
947 Bytecodes::Code bytecode;
948
949 int bbNo = 0;
950 int monitor_count = 0;
951 int prev_bci = -1;
952 while( (bytecode = j.next()) >= 0) {
953 if (j.code() == Bytecodes::_monitorenter) {
954 monitor_count++;
955 }
956
957 int bci = j.bci();
958 if (is_bb_header(bci)) {
959 // Initialize the basicblock structure
960 BasicBlock *bb = _basic_blocks + bbNo;
961 bb->_bci = bci;
962 bb->_max_locals = _max_locals;
963 bb->_max_stack = _max_stack;
964 bb->set_changed(false);
965 bb->_stack_top = BasicBlock::_dead_basic_block; // Initialize all basicblocks are dead.
966 bb->_monitor_top = bad_monitors;
967
968 if (bbNo > 0) {
969 _basic_blocks[bbNo - 1]._end_bci = prev_bci;
970 }
971
972 bbNo++;
973 }
974 // Remember previous bci.
975 prev_bci = bci;
976 }
977 // Set
978 _basic_blocks[bbNo-1]._end_bci = prev_bci;
979
980
981 // Check that the correct number of basicblocks was found
982 if (bbNo !=_bb_count) {
983 if (bbNo < _bb_count) {
984 verify_error("jump into the middle of instruction?");
985 return;
986 } else {
987 verify_error("extra basic blocks - should not happen?");
988 return;
989 }
990 }
991
992 _max_monitors = monitor_count;
993
994 // Now that we have a bound on the depth of the monitor stack, we can
995 // initialize the CellTypeState-related information.
996 init_state();
997
998 // We allocate space for all state-vectors for all basicblocks in one huge
999 // chunk. Then in the next part of the code, we set a pointer in each
1000 // _basic_block that points to each piece.
1001
1002 // The product of bbNo and _state_len can get large if there are lots of
1003 // basic blocks and stack/locals/monitors. Need to check to make sure
1004 // we don't overflow the capacity of a pointer.
1005 if ((unsigned)bbNo > UINTPTR_MAX / sizeof(CellTypeState) / _state_len) {
1006 report_error("The amount of memory required to analyze this method "
1007 "exceeds addressable range");
1008 return;
1009 }
1010
1011 CellTypeState *basicBlockState;
1012 ALLOC_RESOURCE_ARRAY(basicBlockState, CellTypeState, bbNo * _state_len);
1013 memset(basicBlockState, 0, bbNo * _state_len * sizeof(CellTypeState));
1014
1015 // Make a pass over the basicblocks and assign their state vectors.
1016 for (int blockNum=0; blockNum < bbNo; blockNum++) {
1017 BasicBlock *bb = _basic_blocks + blockNum;
1018 bb->_state = basicBlockState + blockNum * _state_len;
1019
1020 #ifdef ASSERT
1021 if (blockNum + 1 < bbNo) {
1022 address bcp = _method->bcp_from(bb->_end_bci);
1023 int bc_len = Bytecodes::java_length_at(_method(), bcp);
1024 assert(bb->_end_bci + bc_len == bb[1]._bci, "unmatched bci info in basicblock");
1025 }
1026 #endif
1027 }
1028 #ifdef ASSERT
1029 { BasicBlock *bb = &_basic_blocks[bbNo-1];
1030 address bcp = _method->bcp_from(bb->_end_bci);
1031 int bc_len = Bytecodes::java_length_at(_method(), bcp);
1032 assert(bb->_end_bci + bc_len == _method->code_size(), "wrong end bci");
1033 }
1034 #endif
1035
1036 // Mark all alive blocks
1037 mark_reachable_code();
1038 }
1039
1040 void GenerateOopMap::setup_method_entry_state() {
1041
1042 // Initialize all locals to 'uninit' and set stack-height to 0
1043 make_context_uninitialized();
1044
1045 // Initialize CellState type of arguments
1046 methodsig_to_effect(method()->signature(), method()->is_static(), vars());
1047
1048 // If some references must be pre-assigned to null, then set that up
1049 initialize_vars();
1050
1051 // This is the start state
1052 merge_state_into_bb(&_basic_blocks[0]);
1053
1054 assert(_basic_blocks[0].changed(), "we are not getting off the ground");
1055 }
1056
1057 // The instruction at bci is changing size by "delta". Update the basic blocks.
1058 void GenerateOopMap::update_basic_blocks(int bci, int delta,
1059 int new_method_size) {
1060 assert(new_method_size >= method()->code_size() + delta,
1061 "new method size is too small");
1062
1063 _bb_hdr_bits.reinitialize(new_method_size);
1064
1065 for(int k = 0; k < _bb_count; k++) {
1066 if (_basic_blocks[k]._bci > bci) {
1067 _basic_blocks[k]._bci += delta;
1068 _basic_blocks[k]._end_bci += delta;
1069 }
1070 _bb_hdr_bits.at_put(_basic_blocks[k]._bci, true);
1071 }
1072 }
1073
1074 //
1075 // Initvars handling
1076 //
1077
1078 void GenerateOopMap::initialize_vars() {
1079 for (int k = 0; k < _init_vars->length(); k++)
1080 _state[_init_vars->at(k)] = CellTypeState::make_slot_ref(k);
1081 }
1082
1083 void GenerateOopMap::add_to_ref_init_set(int localNo) {
1084
1085 log_debug(generateoopmap)("Added init vars: %d", localNo);
1086
1087 // Is it already in the set?
1088 if (_init_vars->contains(localNo) )
1089 return;
1090
1091 _init_vars->append(localNo);
1092 }
1093
1094 //
1095 // Interpreration code
1096 //
1097
1098 void GenerateOopMap::interp_all() {
1099 bool change = true;
1100
1101 while (change && !_got_error) {
1102 change = false;
1103 for (int i = 0; i < _bb_count && !_got_error; i++) {
1104 BasicBlock *bb = &_basic_blocks[i];
1105 if (bb->changed()) {
1106 if (_got_error) return;
1107 change = true;
1108 bb->set_changed(false);
1109 interp_bb(bb);
1110 }
1111 }
1112 }
1113 }
1114
1115 void GenerateOopMap::interp_bb(BasicBlock *bb) {
1116
1117 // We do not want to do anything in case the basic-block has not been initialized. This
1118 // will happen in the case where there is dead-code hang around in a method.
1119 assert(bb->is_reachable(), "should be reachable or deadcode exist");
1120 restore_state(bb);
1121
1122 BytecodeStream itr(_method);
1123
1124 // Set iterator interval to be the current basicblock
1125 int lim_bci = next_bb_start_pc(bb);
1126 itr.set_interval(bb->_bci, lim_bci);
1127 assert(lim_bci != bb->_bci, "must be at least one instruction in a basicblock");
1128 itr.next(); // read first instruction
1129
1130 // Iterates through all bytecodes except the last in a basic block.
1131 // We handle the last one special, since there is controlflow change.
1132 while(itr.next_bci() < lim_bci && !_got_error) {
1133 if (_has_exceptions || _monitor_top != 0) {
1134 // We do not need to interpret the results of exceptional
1135 // continuation from this instruction when the method has no
1136 // exception handlers and the monitor stack is currently
1137 // empty.
1138 do_exception_edge(&itr);
1139 }
1140 interp1(&itr);
1141 itr.next();
1142 }
1143
1144 // Handle last instruction.
1145 if (!_got_error) {
1146 assert(itr.next_bci() == lim_bci, "must point to end");
1147 if (_has_exceptions || _monitor_top != 0) {
1148 do_exception_edge(&itr);
1149 }
1150 interp1(&itr);
1151
1152 bool fall_through = jump_targets_do(&itr, GenerateOopMap::merge_state, nullptr);
1153 if (_got_error) return;
1154
1155 if (itr.code() == Bytecodes::_ret) {
1156 assert(!fall_through, "cannot be set if ret instruction");
1157 // Automatically handles 'wide' ret indices
1158 ret_jump_targets_do(&itr, GenerateOopMap::merge_state, itr.get_index(), nullptr);
1159 } else if (fall_through) {
1160 // Hit end of BB, but the instr. was a fall-through instruction,
1161 // so perform transition as if the BB ended in a "jump".
1162 if (lim_bci != bb[1]._bci) {
1163 verify_error("bytecodes fell through last instruction");
1164 return;
1165 }
1166 merge_state_into_bb(bb + 1);
1167 }
1168 }
1169 }
1170
1171 void GenerateOopMap::do_exception_edge(BytecodeStream* itr) {
1172 // Only check exception edge, if bytecode can trap
1173 if (!Bytecodes::can_trap(itr->code())) return;
1174 switch (itr->code()) {
1175 case Bytecodes::_aload_0:
1176 // These bytecodes can trap for rewriting. We need to assume that
1177 // they do not throw exceptions to make the monitor analysis work.
1178 return;
1179
1180 case Bytecodes::_ireturn:
1181 case Bytecodes::_lreturn:
1182 case Bytecodes::_freturn:
1183 case Bytecodes::_dreturn:
1184 case Bytecodes::_areturn:
1185 case Bytecodes::_return:
1186 // If the monitor stack height is not zero when we leave the method,
1187 // then we are either exiting with a non-empty stack or we have
1188 // found monitor trouble earlier in our analysis. In either case,
1189 // assume an exception could be taken here.
1190 if (_monitor_top == 0) {
1191 return;
1192 }
1193 break;
1194
1195 case Bytecodes::_monitorexit:
1196 // If the monitor stack height is bad_monitors, then we have detected a
1197 // monitor matching problem earlier in the analysis. If the
1198 // monitor stack height is 0, we are about to pop a monitor
1199 // off of an empty stack. In either case, the bytecode
1200 // could throw an exception.
1201 if (_monitor_top != bad_monitors && _monitor_top != 0) {
1202 return;
1203 }
1204 break;
1205
1206 default:
1207 break;
1208 }
1209
1210 if (_has_exceptions) {
1211 int bci = itr->bci();
1212 ExceptionTable exct(method());
1213 for(int i = 0; i< exct.length(); i++) {
1214 int start_pc = exct.start_pc(i);
1215 int end_pc = exct.end_pc(i);
1216 int handler_pc = exct.handler_pc(i);
1217 int catch_type = exct.catch_type_index(i);
1218
1219 if (start_pc <= bci && bci < end_pc) {
1220 BasicBlock *excBB = get_basic_block_at(handler_pc);
1221 guarantee(excBB != nullptr, "no basic block for exception");
1222 CellTypeState *excStk = excBB->stack();
1223 CellTypeState *cOpStck = stack();
1224 CellTypeState cOpStck_0 = cOpStck[0];
1225 int cOpStackTop = _stack_top;
1226
1227 // Exception stacks are always the same.
1228 assert(method()->max_stack() > 0, "sanity check");
1229
1230 // We remembered the size and first element of "cOpStck"
1231 // above; now we temporarily set them to the appropriate
1232 // values for an exception handler. */
1233 cOpStck[0] = CellTypeState::make_slot_ref(_max_locals);
1234 _stack_top = 1;
1235
1236 merge_state_into_bb(excBB);
1237
1238 // Now undo the temporary change.
1239 cOpStck[0] = cOpStck_0;
1240 _stack_top = cOpStackTop;
1241
1242 // If this is a "catch all" handler, then we do not need to
1243 // consider any additional handlers.
1244 if (catch_type == 0) {
1245 return;
1246 }
1247 }
1248 }
1249 }
1250
1251 // It is possible that none of the exception handlers would have caught
1252 // the exception. In this case, we will exit the method. We must
1253 // ensure that the monitor stack is empty in this case.
1254 if (_monitor_top == 0) {
1255 return;
1256 }
1257
1258 // We pessimistically assume that this exception can escape the
1259 // method. (It is possible that it will always be caught, but
1260 // we don't care to analyse the types of the catch clauses.)
1261
1262 // We don't set _monitor_top to bad_monitors because there are no successors
1263 // to this exceptional exit.
1264
1265 if (log_is_enabled(Info, monitormismatch) && _monitor_safe) {
1266 // We check _monitor_safe so that we only report the first mismatched
1267 // exceptional exit.
1268 report_monitor_mismatch("non-empty monitor stack at exceptional exit");
1269 }
1270 _monitor_safe = false;
1271
1272 }
1273
1274 void GenerateOopMap::report_monitor_mismatch(const char *msg) {
1275 LogStream ls(Log(monitormismatch)::info());
1276 ls.print("Monitor mismatch in method ");
1277 method()->print_short_name(&ls);
1278 ls.print_cr(": %s", msg);
1279 }
1280
1281 void GenerateOopMap::print_states(outputStream *os,
1282 CellTypeState* vec, int num) {
1283 for (int i = 0; i < num; i++) {
1284 vec[i].print(os);
1285 }
1286 }
1287
1288 // Print the state values at the current bytecode.
1289 void GenerateOopMap::print_current_state(outputStream* os,
1290 BytecodeStream* currentBC,
1291 bool detailed) {
1292 if (detailed) {
1293 os->print(" %4d vars = ", currentBC->bci());
1294 print_states(os, vars(), _max_locals);
1295 os->print(" %s", Bytecodes::name(currentBC->code()));
1296 } else {
1297 os->print(" %4d vars = '%s' ", currentBC->bci(), state_vec_to_string(vars(), _max_locals));
1298 os->print(" stack = '%s' ", state_vec_to_string(stack(), _stack_top));
1299 if (_monitor_top != bad_monitors) {
1300 os->print(" monitors = '%s' \t%s", state_vec_to_string(monitors(), _monitor_top), Bytecodes::name(currentBC->code()));
1301 } else {
1302 os->print(" [bad monitor stack]");
1303 }
1304 }
1305
1306 switch(currentBC->code()) {
1307 case Bytecodes::_invokevirtual:
1308 case Bytecodes::_invokespecial:
1309 case Bytecodes::_invokestatic:
1310 case Bytecodes::_invokedynamic:
1311 case Bytecodes::_invokeinterface: {
1312 ResourceMark rm;
1313 int idx = currentBC->has_index_u4() ? currentBC->get_index_u4() : currentBC->get_index_u2();
1314 ConstantPool* cp = method()->constants();
1315 int nameAndTypeIdx = cp->name_and_type_ref_index_at(idx, currentBC->code());
1316 int signatureIdx = cp->signature_ref_index_at(nameAndTypeIdx);
1317 Symbol* signature = cp->symbol_at(signatureIdx);
1318 os->print("%s", signature->as_C_string());
1319 }
1320 default:
1321 break;
1322 }
1323
1324 if (detailed) {
1325 os->cr();
1326 os->print(" stack = ");
1327 print_states(os, stack(), _stack_top);
1328 os->cr();
1329 if (_monitor_top != bad_monitors) {
1330 os->print(" monitors = ");
1331 print_states(os, monitors(), _monitor_top);
1332 } else {
1333 os->print(" [bad monitor stack]");
1334 }
1335 }
1336
1337 os->cr();
1338 }
1339
1340 // Sets the current state to be the state after executing the
1341 // current instruction, starting in the current state.
1342 void GenerateOopMap::interp1(BytecodeStream *itr) {
1343 if (log_is_enabled(Trace, generateoopmap)) {
1344 LogStream st(Log(generateoopmap)::trace());
1345 print_current_state(&st, itr, Verbose);
1346 }
1347
1348 // Should we report the results? Result is reported *before* the instruction at the current bci is executed.
1349 // However, not for calls. For calls we do not want to include the arguments, so we postpone the reporting until
1350 // they have been popped (in method ppl).
1351 if (_report_result == true) {
1352 switch(itr->code()) {
1353 case Bytecodes::_invokevirtual:
1354 case Bytecodes::_invokespecial:
1355 case Bytecodes::_invokestatic:
1356 case Bytecodes::_invokedynamic:
1357 case Bytecodes::_invokeinterface:
1358 _itr_send = itr;
1359 _report_result_for_send = true;
1360 break;
1361 default:
1362 fill_stackmap_for_opcodes(itr, vars(), stack(), _stack_top);
1363 break;
1364 }
1365 }
1366
1367 // abstract interpretation of current opcode
1368 switch(itr->code()) {
1369 case Bytecodes::_nop: break;
1370 case Bytecodes::_goto: break;
1371 case Bytecodes::_goto_w: break;
1372 case Bytecodes::_iinc: break;
1373 case Bytecodes::_return: do_return_monitor_check();
1374 break;
1375
1376 case Bytecodes::_aconst_null:
1377 case Bytecodes::_new: ppush1(CellTypeState::make_line_ref(itr->bci()));
1378 break;
1379
1380 case Bytecodes::_iconst_m1:
1381 case Bytecodes::_iconst_0:
1382 case Bytecodes::_iconst_1:
1383 case Bytecodes::_iconst_2:
1384 case Bytecodes::_iconst_3:
1385 case Bytecodes::_iconst_4:
1386 case Bytecodes::_iconst_5:
1387 case Bytecodes::_fconst_0:
1388 case Bytecodes::_fconst_1:
1389 case Bytecodes::_fconst_2:
1390 case Bytecodes::_bipush:
1391 case Bytecodes::_sipush: ppush1(valCTS); break;
1392
1393 case Bytecodes::_lconst_0:
1394 case Bytecodes::_lconst_1:
1395 case Bytecodes::_dconst_0:
1396 case Bytecodes::_dconst_1: ppush(vvCTS); break;
1397
1398 case Bytecodes::_ldc2_w: ppush(vvCTS); break;
1399
1400 case Bytecodes::_ldc: // fall through:
1401 case Bytecodes::_ldc_w: do_ldc(itr->bci()); break;
1402
1403 case Bytecodes::_iload:
1404 case Bytecodes::_fload: ppload(vCTS, itr->get_index()); break;
1405
1406 case Bytecodes::_lload:
1407 case Bytecodes::_dload: ppload(vvCTS,itr->get_index()); break;
1408
1409 case Bytecodes::_aload: ppload(rCTS, itr->get_index()); break;
1410
1411 case Bytecodes::_iload_0:
1412 case Bytecodes::_fload_0: ppload(vCTS, 0); break;
1413 case Bytecodes::_iload_1:
1414 case Bytecodes::_fload_1: ppload(vCTS, 1); break;
1415 case Bytecodes::_iload_2:
1416 case Bytecodes::_fload_2: ppload(vCTS, 2); break;
1417 case Bytecodes::_iload_3:
1418 case Bytecodes::_fload_3: ppload(vCTS, 3); break;
1419
1420 case Bytecodes::_lload_0:
1421 case Bytecodes::_dload_0: ppload(vvCTS, 0); break;
1422 case Bytecodes::_lload_1:
1423 case Bytecodes::_dload_1: ppload(vvCTS, 1); break;
1424 case Bytecodes::_lload_2:
1425 case Bytecodes::_dload_2: ppload(vvCTS, 2); break;
1426 case Bytecodes::_lload_3:
1427 case Bytecodes::_dload_3: ppload(vvCTS, 3); break;
1428
1429 case Bytecodes::_aload_0: ppload(rCTS, 0); break;
1430 case Bytecodes::_aload_1: ppload(rCTS, 1); break;
1431 case Bytecodes::_aload_2: ppload(rCTS, 2); break;
1432 case Bytecodes::_aload_3: ppload(rCTS, 3); break;
1433
1434 case Bytecodes::_iaload:
1435 case Bytecodes::_faload:
1436 case Bytecodes::_baload:
1437 case Bytecodes::_caload:
1438 case Bytecodes::_saload: pp(vrCTS, vCTS); break;
1439
1440 case Bytecodes::_laload: pp(vrCTS, vvCTS); break;
1441 case Bytecodes::_daload: pp(vrCTS, vvCTS); break;
1442
1443 case Bytecodes::_aaload: pp_new_ref(vrCTS, itr->bci()); break;
1444
1445 case Bytecodes::_istore:
1446 case Bytecodes::_fstore: ppstore(vCTS, itr->get_index()); break;
1447
1448 case Bytecodes::_lstore:
1449 case Bytecodes::_dstore: ppstore(vvCTS, itr->get_index()); break;
1450
1451 case Bytecodes::_astore: do_astore(itr->get_index()); break;
1452
1453 case Bytecodes::_istore_0:
1454 case Bytecodes::_fstore_0: ppstore(vCTS, 0); break;
1455 case Bytecodes::_istore_1:
1456 case Bytecodes::_fstore_1: ppstore(vCTS, 1); break;
1457 case Bytecodes::_istore_2:
1458 case Bytecodes::_fstore_2: ppstore(vCTS, 2); break;
1459 case Bytecodes::_istore_3:
1460 case Bytecodes::_fstore_3: ppstore(vCTS, 3); break;
1461
1462 case Bytecodes::_lstore_0:
1463 case Bytecodes::_dstore_0: ppstore(vvCTS, 0); break;
1464 case Bytecodes::_lstore_1:
1465 case Bytecodes::_dstore_1: ppstore(vvCTS, 1); break;
1466 case Bytecodes::_lstore_2:
1467 case Bytecodes::_dstore_2: ppstore(vvCTS, 2); break;
1468 case Bytecodes::_lstore_3:
1469 case Bytecodes::_dstore_3: ppstore(vvCTS, 3); break;
1470
1471 case Bytecodes::_astore_0: do_astore(0); break;
1472 case Bytecodes::_astore_1: do_astore(1); break;
1473 case Bytecodes::_astore_2: do_astore(2); break;
1474 case Bytecodes::_astore_3: do_astore(3); break;
1475
1476 case Bytecodes::_iastore:
1477 case Bytecodes::_fastore:
1478 case Bytecodes::_bastore:
1479 case Bytecodes::_castore:
1480 case Bytecodes::_sastore: ppop(vvrCTS); break;
1481 case Bytecodes::_lastore:
1482 case Bytecodes::_dastore: ppop(vvvrCTS); break;
1483 case Bytecodes::_aastore: ppop(rvrCTS); break;
1484
1485 case Bytecodes::_pop: ppop_any(1); break;
1486 case Bytecodes::_pop2: ppop_any(2); break;
1487
1488 case Bytecodes::_dup: ppdupswap(1, "11"); break;
1489 case Bytecodes::_dup_x1: ppdupswap(2, "121"); break;
1490 case Bytecodes::_dup_x2: ppdupswap(3, "1321"); break;
1491 case Bytecodes::_dup2: ppdupswap(2, "2121"); break;
1492 case Bytecodes::_dup2_x1: ppdupswap(3, "21321"); break;
1493 case Bytecodes::_dup2_x2: ppdupswap(4, "214321"); break;
1494 case Bytecodes::_swap: ppdupswap(2, "12"); break;
1495
1496 case Bytecodes::_iadd:
1497 case Bytecodes::_fadd:
1498 case Bytecodes::_isub:
1499 case Bytecodes::_fsub:
1500 case Bytecodes::_imul:
1501 case Bytecodes::_fmul:
1502 case Bytecodes::_idiv:
1503 case Bytecodes::_fdiv:
1504 case Bytecodes::_irem:
1505 case Bytecodes::_frem:
1506 case Bytecodes::_ishl:
1507 case Bytecodes::_ishr:
1508 case Bytecodes::_iushr:
1509 case Bytecodes::_iand:
1510 case Bytecodes::_ior:
1511 case Bytecodes::_ixor:
1512 case Bytecodes::_l2f:
1513 case Bytecodes::_l2i:
1514 case Bytecodes::_d2f:
1515 case Bytecodes::_d2i:
1516 case Bytecodes::_fcmpl:
1517 case Bytecodes::_fcmpg: pp(vvCTS, vCTS); break;
1518
1519 case Bytecodes::_ladd:
1520 case Bytecodes::_dadd:
1521 case Bytecodes::_lsub:
1522 case Bytecodes::_dsub:
1523 case Bytecodes::_lmul:
1524 case Bytecodes::_dmul:
1525 case Bytecodes::_ldiv:
1526 case Bytecodes::_ddiv:
1527 case Bytecodes::_lrem:
1528 case Bytecodes::_drem:
1529 case Bytecodes::_land:
1530 case Bytecodes::_lor:
1531 case Bytecodes::_lxor: pp(vvvvCTS, vvCTS); break;
1532
1533 case Bytecodes::_ineg:
1534 case Bytecodes::_fneg:
1535 case Bytecodes::_i2f:
1536 case Bytecodes::_f2i:
1537 case Bytecodes::_i2c:
1538 case Bytecodes::_i2s:
1539 case Bytecodes::_i2b: pp(vCTS, vCTS); break;
1540
1541 case Bytecodes::_lneg:
1542 case Bytecodes::_dneg:
1543 case Bytecodes::_l2d:
1544 case Bytecodes::_d2l: pp(vvCTS, vvCTS); break;
1545
1546 case Bytecodes::_lshl:
1547 case Bytecodes::_lshr:
1548 case Bytecodes::_lushr: pp(vvvCTS, vvCTS); break;
1549
1550 case Bytecodes::_i2l:
1551 case Bytecodes::_i2d:
1552 case Bytecodes::_f2l:
1553 case Bytecodes::_f2d: pp(vCTS, vvCTS); break;
1554
1555 case Bytecodes::_lcmp: pp(vvvvCTS, vCTS); break;
1556 case Bytecodes::_dcmpl:
1557 case Bytecodes::_dcmpg: pp(vvvvCTS, vCTS); break;
1558
1559 case Bytecodes::_ifeq:
1560 case Bytecodes::_ifne:
1561 case Bytecodes::_iflt:
1562 case Bytecodes::_ifge:
1563 case Bytecodes::_ifgt:
1564 case Bytecodes::_ifle:
1565 case Bytecodes::_tableswitch: ppop1(valCTS);
1566 break;
1567 case Bytecodes::_ireturn:
1568 case Bytecodes::_freturn: do_return_monitor_check();
1569 ppop1(valCTS);
1570 break;
1571 case Bytecodes::_if_icmpeq:
1572 case Bytecodes::_if_icmpne:
1573 case Bytecodes::_if_icmplt:
1574 case Bytecodes::_if_icmpge:
1575 case Bytecodes::_if_icmpgt:
1576 case Bytecodes::_if_icmple: ppop(vvCTS);
1577 break;
1578
1579 case Bytecodes::_lreturn: do_return_monitor_check();
1580 ppop(vvCTS);
1581 break;
1582
1583 case Bytecodes::_dreturn: do_return_monitor_check();
1584 ppop(vvCTS);
1585 break;
1586
1587 case Bytecodes::_if_acmpeq:
1588 case Bytecodes::_if_acmpne: ppop(rrCTS); break;
1589
1590 case Bytecodes::_jsr: do_jsr(itr->dest()); break;
1591 case Bytecodes::_jsr_w: do_jsr(itr->dest_w()); break;
1592
1593 case Bytecodes::_getstatic: do_field(true, true, itr->get_index_u2(), itr->bci(), itr->code()); break;
1594 case Bytecodes::_putstatic: do_field(false, true, itr->get_index_u2(), itr->bci(), itr->code()); break;
1595 case Bytecodes::_getfield: do_field(true, false, itr->get_index_u2(), itr->bci(), itr->code()); break;
1596 case Bytecodes::_putfield: do_field(false, false, itr->get_index_u2(), itr->bci(), itr->code()); break;
1597
1598 case Bytecodes::_invokeinterface:
1599 case Bytecodes::_invokevirtual:
1600 case Bytecodes::_invokespecial: do_method(false, itr->get_index_u2(), itr->bci(), itr->code()); break;
1601 case Bytecodes::_invokestatic: do_method(true , itr->get_index_u2(), itr->bci(), itr->code()); break;
1602 case Bytecodes::_invokedynamic: do_method(true , itr->get_index_u4(), itr->bci(), itr->code()); break;
1603 case Bytecodes::_newarray:
1604 case Bytecodes::_anewarray: pp_new_ref(vCTS, itr->bci()); break;
1605 case Bytecodes::_checkcast: do_checkcast(); break;
1606 case Bytecodes::_arraylength:
1607 case Bytecodes::_instanceof: pp(rCTS, vCTS); break;
1608 case Bytecodes::_monitorenter: do_monitorenter(itr->bci()); break;
1609 case Bytecodes::_monitorexit: do_monitorexit(itr->bci()); break;
1610
1611 case Bytecodes::_athrow: // handled by do_exception_edge() BUT ...
1612 // vlh(apple): do_exception_edge() does not get
1613 // called if method has no exception handlers
1614 if ((!_has_exceptions) && (_monitor_top > 0)) {
1615 _monitor_safe = false;
1616 }
1617 break;
1618
1619 case Bytecodes::_areturn: do_return_monitor_check();
1620 ppop1(refCTS);
1621 break;
1622 case Bytecodes::_ifnull:
1623 case Bytecodes::_ifnonnull: ppop1(refCTS); break;
1624 case Bytecodes::_multianewarray: do_multianewarray(*(itr->bcp()+3), itr->bci()); break;
1625
1626 case Bytecodes::_wide: fatal("Iterator should skip this bytecode"); break;
1627 case Bytecodes::_ret: break;
1628
1629 // Java opcodes
1630 case Bytecodes::_lookupswitch: ppop1(valCTS); break;
1631
1632 default:
1633 tty->print("unexpected opcode: %d\n", itr->code());
1634 ShouldNotReachHere();
1635 break;
1636 }
1637 }
1638
1639 void GenerateOopMap::check_type(CellTypeState expected, CellTypeState actual) {
1640 if (!expected.equal_kind(actual)) {
1641 verify_error("wrong type on stack (found: %c expected: %c)", actual.to_char(), expected.to_char());
1642 }
1643 }
1644
1645 void GenerateOopMap::ppstore(CellTypeState *in, int loc_no) {
1646 while(!(*in).is_bottom()) {
1647 CellTypeState expected =*in++;
1648 CellTypeState actual = pop();
1649 check_type(expected, actual);
1650 assert(loc_no >= 0, "sanity check");
1651 set_var(loc_no++, actual);
1652 }
1653 }
1654
1655 void GenerateOopMap::ppload(CellTypeState *out, int loc_no) {
1656 while(!(*out).is_bottom()) {
1657 CellTypeState out1 = *out++;
1658 CellTypeState vcts = get_var(loc_no);
1659 assert(out1.can_be_reference() || out1.can_be_value(),
1660 "can only load refs. and values.");
1661 if (out1.is_reference()) {
1662 assert(loc_no>=0, "sanity check");
1663 if (!vcts.is_reference()) {
1664 // We were asked to push a reference, but the type of the
1665 // variable can be something else
1666 _conflict = true;
1667 if (vcts.can_be_uninit()) {
1668 // It is a ref-uninit conflict (at least). If there are other
1669 // problems, we'll get them in the next round
1670 add_to_ref_init_set(loc_no);
1671 vcts = out1;
1672 } else {
1673 // It wasn't a ref-uninit conflict. So must be a
1674 // ref-val or ref-pc conflict. Split the variable.
1675 record_refval_conflict(loc_no);
1676 vcts = out1;
1677 }
1678 push(out1); // recover...
1679 } else {
1680 push(vcts); // preserve reference.
1681 }
1682 // Otherwise it is a conflict, but one that verification would
1683 // have caught if illegal. In particular, it can't be a topCTS
1684 // resulting from mergeing two difference pcCTS's since the verifier
1685 // would have rejected any use of such a merge.
1686 } else {
1687 push(out1); // handle val/init conflict
1688 }
1689 loc_no++;
1690 }
1691 }
1692
1693 void GenerateOopMap::ppdupswap(int poplen, const char *out) {
1694 CellTypeState actual[5];
1695 assert(poplen < 5, "this must be less than length of actual vector");
1696
1697 // Pop all arguments.
1698 for (int i = 0; i < poplen; i++) {
1699 actual[i] = pop();
1700 }
1701 // Field _state is uninitialized when calling push.
1702 for (int i = poplen; i < 5; i++) {
1703 actual[i] = CellTypeState::uninit;
1704 }
1705
1706 // put them back
1707 char push_ch = *out++;
1708 while (push_ch != '\0') {
1709 int idx = push_ch - '1';
1710 assert(idx >= 0 && idx < poplen, "wrong arguments");
1711 push(actual[idx]);
1712 push_ch = *out++;
1713 }
1714 }
1715
1716 void GenerateOopMap::ppop1(CellTypeState out) {
1717 CellTypeState actual = pop();
1718 check_type(out, actual);
1719 }
1720
1721 void GenerateOopMap::ppop(CellTypeState *out) {
1722 while (!(*out).is_bottom()) {
1723 ppop1(*out++);
1724 }
1725 }
1726
1727 void GenerateOopMap::ppush1(CellTypeState in) {
1728 assert(in.is_reference() || in.is_value(), "sanity check");
1729 push(in);
1730 }
1731
1732 void GenerateOopMap::ppush(CellTypeState *in) {
1733 while (!(*in).is_bottom()) {
1734 ppush1(*in++);
1735 }
1736 }
1737
1738 void GenerateOopMap::pp(CellTypeState *in, CellTypeState *out) {
1739 ppop(in);
1740 ppush(out);
1741 }
1742
1743 void GenerateOopMap::pp_new_ref(CellTypeState *in, int bci) {
1744 ppop(in);
1745 ppush1(CellTypeState::make_line_ref(bci));
1746 }
1747
1748 void GenerateOopMap::ppop_any(int poplen) {
1749 if (_stack_top >= poplen) {
1750 _stack_top -= poplen;
1751 } else {
1752 verify_error("stack underflow");
1753 }
1754 }
1755
1756 // Replace all occurrences of the state 'match' with the state 'replace'
1757 // in our current state vector.
1758 void GenerateOopMap::replace_all_CTS_matches(CellTypeState match,
1759 CellTypeState replace) {
1760 int i;
1761 int len = _max_locals + _stack_top;
1762 bool change = false;
1763
1764 for (i = len - 1; i >= 0; i--) {
1765 if (match.equal(_state[i])) {
1766 _state[i] = replace;
1767 }
1768 }
1769
1770 if (_monitor_top > 0) {
1771 int base = _max_locals + _max_stack;
1772 len = base + _monitor_top;
1773 for (i = len - 1; i >= base; i--) {
1774 if (match.equal(_state[i])) {
1775 _state[i] = replace;
1776 }
1777 }
1778 }
1779 }
1780
1781 void GenerateOopMap::do_checkcast() {
1782 CellTypeState actual = pop();
1783 check_type(refCTS, actual);
1784 push(actual);
1785 }
1786
1787 void GenerateOopMap::do_monitorenter(int bci) {
1788 CellTypeState actual = pop();
1789 if (_monitor_top == bad_monitors) {
1790 return;
1791 }
1792
1793 // Bail out when we get repeated locks on an identical monitor. This case
1794 // isn't too hard to handle and can be made to work if supporting nested
1795 // redundant synchronized statements becomes a priority.
1796 //
1797 // See also "Note" in do_monitorexit(), below.
1798 if (actual.is_lock_reference()) {
1799 _monitor_top = bad_monitors;
1800 _monitor_safe = false;
1801
1802 if (log_is_enabled(Info, monitormismatch)) {
1803 report_monitor_mismatch("nested redundant lock -- bailout...");
1804 }
1805 return;
1806 }
1807
1808 CellTypeState lock = CellTypeState::make_lock_ref(bci);
1809 check_type(refCTS, actual);
1810 if (!actual.is_info_top()) {
1811 replace_all_CTS_matches(actual, lock);
1812 monitor_push(lock);
1813 }
1814 }
1815
1816 void GenerateOopMap::do_monitorexit(int bci) {
1817 CellTypeState actual = pop();
1818 if (_monitor_top == bad_monitors) {
1819 return;
1820 }
1821 check_type(refCTS, actual);
1822 CellTypeState expected = monitor_pop();
1823 if (!actual.is_lock_reference() || !expected.equal(actual)) {
1824 // The monitor we are exiting is not verifiably the one
1825 // on the top of our monitor stack. This causes a monitor
1826 // mismatch.
1827 _monitor_top = bad_monitors;
1828 _monitor_safe = false;
1829
1830 // We need to mark this basic block as changed so that
1831 // this monitorexit will be visited again. We need to
1832 // do this to ensure that we have accounted for the
1833 // possibility that this bytecode will throw an
1834 // exception.
1835 BasicBlock* bb = get_basic_block_containing(bci);
1836 guarantee(bb != nullptr, "no basic block for bci");
1837 bb->set_changed(true);
1838 bb->_monitor_top = bad_monitors;
1839
1840 if (log_is_enabled(Info, monitormismatch)) {
1841 report_monitor_mismatch("improper monitor pair");
1842 }
1843 } else {
1844 // This code is a fix for the case where we have repeated
1845 // locking of the same object in straightline code. We clear
1846 // out the lock when it is popped from the monitor stack
1847 // and replace it with an unobtrusive reference value that can
1848 // be locked again.
1849 //
1850 // Note: when generateOopMap is fixed to properly handle repeated,
1851 // nested, redundant locks on the same object, then this
1852 // fix will need to be removed at that time.
1853 replace_all_CTS_matches(actual, CellTypeState::make_line_ref(bci));
1854 }
1855 }
1856
1857 void GenerateOopMap::do_return_monitor_check() {
1858 if (_monitor_top > 0) {
1859 // The monitor stack must be empty when we leave the method
1860 // for the monitors to be properly matched.
1861 _monitor_safe = false;
1862
1863 // Since there are no successors to the *return bytecode, it
1864 // isn't necessary to set _monitor_top to bad_monitors.
1865
1866 if (log_is_enabled(Info, monitormismatch)) {
1867 report_monitor_mismatch("non-empty monitor stack at return");
1868 }
1869 }
1870 }
1871
1872 void GenerateOopMap::do_jsr(int targ_bci) {
1873 push(CellTypeState::make_addr(targ_bci));
1874 }
1875
1876
1877
1878 void GenerateOopMap::do_ldc(int bci) {
1879 Bytecode_loadconstant ldc(methodHandle(Thread::current(), method()), bci);
1880 ConstantPool* cp = method()->constants();
1881 constantTag tag = cp->tag_at(ldc.pool_index()); // idx is index in resolved_references
1882 BasicType bt = ldc.result_type();
1883 #ifdef ASSERT
1884 BasicType tag_bt = (tag.is_dynamic_constant() || tag.is_dynamic_constant_in_error()) ? bt : tag.basic_type();
1885 assert(bt == tag_bt, "same result");
1886 #endif
1887 CellTypeState cts;
1888 if (is_reference_type(bt)) { // could be T_ARRAY with condy
1889 assert(!tag.is_string_index() && !tag.is_klass_index(), "Unexpected index tag");
1890 cts = CellTypeState::make_line_ref(bci);
1891 } else {
1892 cts = valCTS;
1893 }
1894 ppush1(cts);
1895 }
1896
1897 void GenerateOopMap::do_multianewarray(int dims, int bci) {
1898 assert(dims >= 1, "sanity check");
1899 for(int i = dims -1; i >=0; i--) {
1900 ppop1(valCTS);
1901 }
1902 ppush1(CellTypeState::make_line_ref(bci));
1903 }
1904
1905 void GenerateOopMap::do_astore(int idx) {
1906 CellTypeState r_or_p = pop();
1907 if (!r_or_p.is_address() && !r_or_p.is_reference()) {
1908 // We actually expected ref or pc, but we only report that we expected a ref. It does not
1909 // really matter (at least for now)
1910 verify_error("wrong type on stack (found: %c, expected: {pr})", r_or_p.to_char());
1911 return;
1912 }
1913 set_var(idx, r_or_p);
1914 }
1915
1916 // Copies bottom/zero terminated CTS string from "src" into "dst".
1917 // Does NOT terminate with a bottom. Returns the number of cells copied.
1918 int GenerateOopMap::copy_cts(CellTypeState *dst, CellTypeState *src) {
1919 int idx = 0;
1920 while (!src[idx].is_bottom()) {
1921 dst[idx] = src[idx];
1922 idx++;
1923 }
1924 return idx;
1925 }
1926
1927 void GenerateOopMap::do_field(int is_get, int is_static, int idx, int bci, Bytecodes::Code bc) {
1928 // Dig up signature for field in constant pool
1929 ConstantPool* cp = method()->constants();
1930 int nameAndTypeIdx = cp->name_and_type_ref_index_at(idx, bc);
1931 int signatureIdx = cp->signature_ref_index_at(nameAndTypeIdx);
1932 Symbol* signature = cp->symbol_at(signatureIdx);
1933
1934 CellTypeState temp[4];
1935 CellTypeState *eff = signature_to_effect(signature, bci, temp);
1936
1937 CellTypeState in[4];
1938 CellTypeState *out;
1939 int i = 0;
1940
1941 if (is_get) {
1942 out = eff;
1943 } else {
1944 out = epsilonCTS;
1945 i = copy_cts(in, eff);
1946 }
1947 if (!is_static) {
1948 in[i++] = CellTypeState::ref;
1949 }
1950 in[i] = CellTypeState::bottom;
1951 assert(i<=3, "sanity check");
1952 pp(in, out);
1953 }
1954
1955 void GenerateOopMap::do_method(int is_static, int idx, int bci, Bytecodes::Code bc) {
1956 // Dig up signature for field in constant pool
1957 ConstantPool* cp = _method->constants();
1958 Symbol* signature = cp->signature_ref_at(idx, bc);
1959
1960 // Parse method signature
1961 CellTypeState out[4];
1962 CellTypeState in[MAXARGSIZE+1]; // Includes result
1963 ComputeCallStack cse(signature);
1964
1965 // Compute return type
1966 int res_length= cse.compute_for_returntype(out);
1967
1968 // Temporary hack.
1969 if (out[0].equal(CellTypeState::ref) && out[1].equal(CellTypeState::bottom)) {
1970 out[0] = CellTypeState::make_line_ref(bci);
1971 }
1972
1973 assert(res_length<=4, "max value should be vv");
1974
1975 // Compute arguments
1976 int arg_length = cse.compute_for_parameters(is_static != 0, in);
1977 assert(arg_length<=MAXARGSIZE, "too many locals");
1978
1979 // Pop arguments
1980 for (int i = arg_length - 1; i >= 0; i--) ppop1(in[i]);// Do args in reverse order.
1981
1982 // Report results
1983 if (_report_result_for_send == true) {
1984 fill_stackmap_for_opcodes(_itr_send, vars(), stack(), _stack_top);
1985 _report_result_for_send = false;
1986 }
1987
1988 // Push return address
1989 ppush(out);
1990 }
1991
1992 // This is used to parse the signature for fields, since they are very simple...
1993 CellTypeState *GenerateOopMap::signature_to_effect(const Symbol* sig, int bci, CellTypeState *out) {
1994 // Object and array
1995 BasicType bt = Signature::basic_type(sig);
1996 if (is_reference_type(bt)) {
1997 out[0] = CellTypeState::make_line_ref(bci);
1998 out[1] = CellTypeState::bottom;
1999 return out;
2000 }
2001 if (is_double_word_type(bt)) return vvCTS; // Long and Double
2002 if (bt == T_VOID) return epsilonCTS; // Void
2003 return vCTS; // Otherwise
2004 }
2005
2006 uint64_t GenerateOopMap::_total_byte_count = 0;
2007 elapsedTimer GenerateOopMap::_total_oopmap_time;
2008
2009 // This function assumes "bcs" is at a "ret" instruction and that the vars
2010 // state is valid for that instruction. Furthermore, the ret instruction
2011 // must be the last instruction in "bb" (we store information about the
2012 // "ret" in "bb").
2013 void GenerateOopMap::ret_jump_targets_do(BytecodeStream *bcs, jmpFct_t jmpFct, int varNo, int *data) {
2014 CellTypeState ra = vars()[varNo];
2015 if (!ra.is_good_address()) {
2016 verify_error("ret returns from two jsr subroutines?");
2017 return;
2018 }
2019 int target = ra.get_info();
2020
2021 RetTableEntry* rtEnt = _rt.find_jsrs_for_target(target);
2022 int bci = bcs->bci();
2023 for (int i = 0; i < rtEnt->nof_jsrs(); i++) {
2024 int target_bci = rtEnt->jsrs(i);
2025 // Make sure a jrtRet does not set the changed bit for dead basicblock.
2026 BasicBlock* jsr_bb = get_basic_block_containing(target_bci - 1);
2027 DEBUG_ONLY(BasicBlock* target_bb = &jsr_bb[1];)
2028 assert(target_bb == get_basic_block_at(target_bci), "wrong calc. of successor basicblock");
2029 bool alive = jsr_bb->is_alive();
2030 log_debug(generateoopmap)("pc = %d, ret -> %d alive: %s", bci, target_bci, alive ? "true" : "false");
2031 if (alive) jmpFct(this, target_bci, data);
2032 }
2033 }
2034
2035 //
2036 // Debug method
2037 //
2038 char* GenerateOopMap::state_vec_to_string(CellTypeState* vec, int len) {
2039 #ifdef ASSERT
2040 int checklen = MAX3(_max_locals, _max_stack, _max_monitors) + 1;
2041 assert(len < checklen, "state_vec_buf overflow");
2042 #endif
2043 for (int i = 0; i < len; i++) _state_vec_buf[i] = vec[i].to_char();
2044 _state_vec_buf[len] = 0;
2045 return _state_vec_buf;
2046 }
2047
2048 #ifndef PRODUCT
2049 void GenerateOopMap::print_time() {
2050 tty->print_cr ("Accumulated oopmap times:");
2051 tty->print_cr ("---------------------------");
2052 tty->print_cr (" Total : %3.3f sec.", GenerateOopMap::_total_oopmap_time.seconds());
2053 tty->print_cr (" (%3.0f bytecodes per sec) ",
2054 (double)GenerateOopMap::_total_byte_count / GenerateOopMap::_total_oopmap_time.seconds());
2055 }
2056 #endif
2057
2058 //
2059 // ============ Main Entry Point ===========
2060 //
2061 GenerateOopMap::GenerateOopMap(const methodHandle& method) {
2062 // We have to initialize all variables here, that can be queried directly
2063 _method = method;
2064 _max_locals=0;
2065 _init_vars = nullptr;
2066 }
2067
2068 bool GenerateOopMap::compute_map(Thread* current) {
2069 #ifndef PRODUCT
2070 if (TimeOopMap) {
2071 _total_byte_count += method()->code_size();
2072 TraceTime t_all(nullptr, &_total_oopmap_time, TimeOopMap);
2073 }
2074 #endif
2075 TraceTime t_single("oopmap time", TRACETIME_LOG(Debug, generateoopmap));
2076
2077 // Initialize values
2078 _got_error = false;
2079 _conflict = false;
2080 _max_locals = method()->max_locals();
2081 _max_stack = method()->max_stack();
2082 _has_exceptions = (method()->has_exception_handler());
2083 _nof_refval_conflicts = 0;
2084 _init_vars = new GrowableArray<intptr_t>(5); // There are seldom more than 5 init_vars
2085 _report_result = false;
2086 _report_result_for_send = false;
2087 _new_var_map = nullptr;
2088 _ret_adr_tos = new GrowableArray<int>(5); // 5 seems like a good number;
2089 _did_rewriting = false;
2090 _did_relocation = false;
2091
2092 if (log_is_enabled(Debug, generateoopmap)) {
2093 ResourceMark rm;
2094 LogStream st(Log(generateoopmap)::debug());
2095 st.print_cr("Method name: %s\n", method()->name()->as_C_string());
2096 _method->print_codes_on(&st);
2097 st.print_cr("Exception table:");
2098 ExceptionTable excps(method());
2099 for (int i = 0; i < excps.length(); i ++) {
2100 st.print_cr("[%d - %d] -> %d",
2101 excps.start_pc(i), excps.end_pc(i), excps.handler_pc(i));
2102 }
2103 }
2104
2105 // if no code - do nothing
2106 // compiler needs info
2107 if (method()->code_size() == 0 || _max_locals + method()->max_stack() == 0) {
2108 return true;
2109 }
2110 // Step 1: Compute all jump targets and their return value
2111 if (!_got_error)
2112 _rt.compute_ret_table(_method);
2113
2114 // Step 2: Find all basic blocks and count GC points
2115 if (!_got_error)
2116 mark_bbheaders();
2117
2118 // Step 3: Calculate stack maps
2119 if (!_got_error)
2120 do_interpretation();
2121
2122 // Step 4:Return results
2123 if (!_got_error && report_results())
2124 report_result();
2125
2126 return !_got_error;
2127 }
2128
2129 // Error handling methods
2130 //
2131 // If we compute from a suitable JavaThread then we create an exception for the GenerateOopMap
2132 // calling code to retrieve (via exception()) and throw if desired (in most cases errors are ignored).
2133 // Otherwise it is considered a fatal error to hit malformed bytecode.
2134 void GenerateOopMap::error_work(const char *format, va_list ap) {
2135 _got_error = true;
2136 char msg_buffer[512];
2137 (void) os::vsnprintf(msg_buffer, sizeof(msg_buffer), format, ap);
2138 // Append method name
2139 char msg_buffer2[512];
2140 (void) os::snprintf(msg_buffer2, sizeof(msg_buffer2), "%s in method %s", msg_buffer, method()->name()->as_C_string());
2141 Thread* current = Thread::current();
2142 if (current->can_call_java()) {
2143 _exception = Exceptions::new_exception(JavaThread::cast(current),
2144 vmSymbols::java_lang_LinkageError(),
2145 msg_buffer2);
2146 } else {
2147 fatal("%s", msg_buffer2);
2148 }
2149 }
2150
2151 void GenerateOopMap::report_error(const char *format, ...) {
2152 va_list ap;
2153 va_start(ap, format);
2154 error_work(format, ap);
2155 }
2156
2157 void GenerateOopMap::verify_error(const char *format, ...) {
2158 // We do not distinguish between different types of errors for verification
2159 // errors. Let the verifier give a better message.
2160 report_error("Illegal class file encountered. Try running with -Xverify:all");
2161 }
2162
2163 //
2164 // Report result opcodes
2165 //
2166 void GenerateOopMap::report_result() {
2167
2168 log_debug(generateoopmap)("Report result pass");
2169
2170 // We now want to report the result of the parse
2171 _report_result = true;
2172
2173 // Mark everything changed, then do one interpretation pass.
2174 for (int i = 0; i<_bb_count; i++) {
2175 if (_basic_blocks[i].is_reachable()) {
2176 _basic_blocks[i].set_changed(true);
2177 interp_bb(&_basic_blocks[i]);
2178 }
2179 }
2180
2181 _report_result = false;
2182 }
2183
2184 void GenerateOopMap::result_for_basicblock(int bci) {
2185 log_debug(generateoopmap)("Report result pass for basicblock");
2186
2187 // We now want to report the result of the parse
2188 _report_result = true;
2189
2190 // Find basicblock and report results
2191 BasicBlock* bb = get_basic_block_containing(bci);
2192 guarantee(bb != nullptr, "no basic block for bci");
2193 assert(bb->is_reachable(), "getting result from unreachable basicblock %d", bci);
2194 bb->set_changed(true);
2195 interp_bb(bb);
2196 }
2197
2198 //
2199 // Conflict handling code
2200 //
2201
2202 void GenerateOopMap::record_refval_conflict(int varNo) {
2203 assert(varNo>=0 && varNo< _max_locals, "index out of range");
2204
2205 log_trace(generateoopmap)("### Conflict detected (local no: %d)", varNo);
2206
2207 if (!_new_var_map) {
2208 _new_var_map = NEW_RESOURCE_ARRAY(int, _max_locals);
2209 for (int k = 0; k < _max_locals; k++) _new_var_map[k] = k;
2210 }
2211
2212 if ( _new_var_map[varNo] == varNo) {
2213 // Check if max. number of locals has been reached
2214 if (_max_locals + _nof_refval_conflicts >= MAX_LOCAL_VARS) {
2215 report_error("Rewriting exceeded local variable limit");
2216 return;
2217 }
2218 _new_var_map[varNo] = _max_locals + _nof_refval_conflicts;
2219 _nof_refval_conflicts++;
2220 }
2221 }
2222
2223 void GenerateOopMap::rewrite_refval_conflicts()
2224 {
2225 // We can get here two ways: Either a rewrite conflict was detected, or
2226 // an uninitialize reference was detected. In the second case, we do not
2227 // do any rewriting, we just want to recompute the reference set with the
2228 // new information
2229
2230 int nof_conflicts = 0; // Used for debugging only
2231
2232 if ( _nof_refval_conflicts == 0 )
2233 return;
2234
2235 // Check if rewrites are allowed in this parse.
2236 if (!allow_rewrites()) {
2237 fatal("Rewriting method not allowed at this stage");
2238 }
2239
2240
2241 // Tracing flag
2242 _did_rewriting = true;
2243
2244 if (log_is_enabled(Trace, generateoopmap)) {
2245 ResourceMark rm;
2246 LogStream st(Log(generateoopmap)::trace());
2247 st.print_cr("ref/value conflict for method %s - bytecodes are getting rewritten", method()->name()->as_C_string());
2248 method()->print_on(&st);
2249 method()->print_codes_on(&st);
2250 }
2251
2252 assert(_new_var_map!=nullptr, "nothing to rewrite");
2253 assert(_conflict==true, "We should not be here");
2254
2255 compute_ret_adr_at_TOS();
2256 if (!_got_error) {
2257 for (int k = 0; k < _max_locals && !_got_error; k++) {
2258 if (_new_var_map[k] != k) {
2259 log_trace(generateoopmap)("Rewriting: %d -> %d", k, _new_var_map[k]);
2260 rewrite_refval_conflict(k, _new_var_map[k]);
2261 if (_got_error) return;
2262 nof_conflicts++;
2263 }
2264 }
2265 }
2266
2267 assert(nof_conflicts == _nof_refval_conflicts, "sanity check");
2268
2269 // Adjust the number of locals
2270 method()->set_max_locals(_max_locals+_nof_refval_conflicts);
2271 _max_locals += _nof_refval_conflicts;
2272
2273 // That was that...
2274 _new_var_map = nullptr;
2275 _nof_refval_conflicts = 0;
2276 }
2277
2278 void GenerateOopMap::rewrite_refval_conflict(int from, int to) {
2279 bool startOver;
2280 do {
2281 // Make sure that the BytecodeStream is constructed in the loop, since
2282 // during rewriting a new method is going to be used, and the next time
2283 // around we want to use that.
2284 BytecodeStream bcs(_method);
2285 startOver = false;
2286
2287 while( !startOver && !_got_error &&
2288 // test bcs in case method changed and it became invalid
2289 bcs.next() >=0) {
2290 startOver = rewrite_refval_conflict_inst(&bcs, from, to);
2291 }
2292 } while (startOver && !_got_error);
2293 }
2294
2295 /* If the current instruction is one that uses local variable "from"
2296 in a ref way, change it to use "to". There's a subtle reason why we
2297 renumber the ref uses and not the non-ref uses: non-ref uses may be
2298 2 slots wide (double, long) which would necessitate keeping track of
2299 whether we should add one or two variables to the method. If the change
2300 affected the width of some instruction, returns "TRUE"; otherwise, returns "FALSE".
2301 Another reason for moving ref's value is for solving (addr, ref) conflicts, which
2302 both uses aload/astore methods.
2303 */
2304 bool GenerateOopMap::rewrite_refval_conflict_inst(BytecodeStream *itr, int from, int to) {
2305 Bytecodes::Code bc = itr->code();
2306 int index;
2307 int bci = itr->bci();
2308
2309 if (is_aload(itr, &index) && index == from) {
2310 log_trace(generateoopmap)("Rewriting aload at bci: %d", bci);
2311 return rewrite_load_or_store(itr, Bytecodes::_aload, Bytecodes::_aload_0, to);
2312 }
2313
2314 if (is_astore(itr, &index) && index == from) {
2315 if (!stack_top_holds_ret_addr(bci)) {
2316 log_trace(generateoopmap)("Rewriting astore at bci: %d", bci);
2317 return rewrite_load_or_store(itr, Bytecodes::_astore, Bytecodes::_astore_0, to);
2318 } else {
2319 log_trace(generateoopmap)("Suppress rewriting of astore at bci: %d", bci);
2320 }
2321 }
2322
2323 return false;
2324 }
2325
2326 // The argument to this method is:
2327 // bc : Current bytecode
2328 // bcN : either _aload or _astore
2329 // bc0 : either _aload_0 or _astore_0
2330 bool GenerateOopMap::rewrite_load_or_store(BytecodeStream *bcs, Bytecodes::Code bcN, Bytecodes::Code bc0, unsigned int varNo) {
2331 assert(bcN == Bytecodes::_astore || bcN == Bytecodes::_aload, "wrong argument (bcN)");
2332 assert(bc0 == Bytecodes::_astore_0 || bc0 == Bytecodes::_aload_0, "wrong argument (bc0)");
2333 int ilen = Bytecodes::length_at(_method(), bcs->bcp());
2334 int newIlen;
2335
2336 if (ilen == 4) {
2337 // Original instruction was wide; keep it wide for simplicity
2338 newIlen = 4;
2339 } else if (varNo < 4)
2340 newIlen = 1;
2341 else if (varNo >= 256)
2342 newIlen = 4;
2343 else
2344 newIlen = 2;
2345
2346 // If we need to relocate in order to patch the byte, we
2347 // do the patching in a temp. buffer, that is passed to the reloc.
2348 // The patching of the bytecode stream is then done by the Relocator.
2349 // This is necessary, since relocating the instruction at a certain bci, might
2350 // also relocate that instruction, e.g., if a _goto before it gets widen to a _goto_w.
2351 // Hence, we do not know which bci to patch after relocation.
2352
2353 assert(newIlen <= 4, "sanity check");
2354 u_char inst_buffer[4]; // Max. instruction size is 4.
2355 address bcp;
2356
2357 if (newIlen != ilen) {
2358 // Relocation needed do patching in temp. buffer
2359 bcp = (address)inst_buffer;
2360 } else {
2361 bcp = _method->bcp_from(bcs->bci());
2362 }
2363
2364 // Patch either directly in Method* or in temp. buffer
2365 if (newIlen == 1) {
2366 assert(varNo < 4, "varNo too large");
2367 *bcp = (u1)(bc0 + varNo);
2368 } else if (newIlen == 2) {
2369 assert(varNo < 256, "2-byte index needed!");
2370 *(bcp + 0) = bcN;
2371 *(bcp + 1) = (u1)varNo;
2372 } else {
2373 assert(newIlen == 4, "Wrong instruction length");
2374 *(bcp + 0) = Bytecodes::_wide;
2375 *(bcp + 1) = bcN;
2376 Bytes::put_Java_u2(bcp+2, (u2)varNo);
2377 }
2378
2379 if (newIlen != ilen) {
2380 expand_current_instr(bcs->bci(), ilen, newIlen, inst_buffer);
2381 }
2382
2383
2384 return (newIlen != ilen);
2385 }
2386
2387 class RelocCallback : public RelocatorListener {
2388 private:
2389 GenerateOopMap* _gom;
2390 public:
2391 RelocCallback(GenerateOopMap* gom) { _gom = gom; };
2392
2393 // Callback method
2394 virtual void relocated(int bci, int delta, int new_code_length) {
2395 _gom->update_basic_blocks (bci, delta, new_code_length);
2396 _gom->update_ret_adr_at_TOS(bci, delta);
2397 _gom->_rt.update_ret_table (bci, delta);
2398 }
2399 };
2400
2401 // Returns true if expanding was successful. Otherwise, reports an error and
2402 // returns false.
2403 void GenerateOopMap::expand_current_instr(int bci, int ilen, int newIlen, u_char inst_buffer[]) {
2404 JavaThread* THREAD = JavaThread::current(); // For exception macros.
2405 RelocCallback rcb(this);
2406 Relocator rc(_method, &rcb);
2407 methodHandle m= rc.insert_space_at(bci, newIlen, inst_buffer, THREAD);
2408 if (m.is_null() || HAS_PENDING_EXCEPTION) {
2409 report_error("could not rewrite method - exception occurred or bytecode buffer overflow");
2410 return;
2411 }
2412
2413 // Relocator returns a new method.
2414 _did_relocation = true;
2415 _method = m;
2416 }
2417
2418
2419 bool GenerateOopMap::is_astore(BytecodeStream *itr, int *index) {
2420 Bytecodes::Code bc = itr->code();
2421 switch(bc) {
2422 case Bytecodes::_astore_0:
2423 case Bytecodes::_astore_1:
2424 case Bytecodes::_astore_2:
2425 case Bytecodes::_astore_3:
2426 *index = bc - Bytecodes::_astore_0;
2427 return true;
2428 case Bytecodes::_astore:
2429 *index = itr->get_index();
2430 return true;
2431 default:
2432 return false;
2433 }
2434 }
2435
2436 bool GenerateOopMap::is_aload(BytecodeStream *itr, int *index) {
2437 Bytecodes::Code bc = itr->code();
2438 switch(bc) {
2439 case Bytecodes::_aload_0:
2440 case Bytecodes::_aload_1:
2441 case Bytecodes::_aload_2:
2442 case Bytecodes::_aload_3:
2443 *index = bc - Bytecodes::_aload_0;
2444 return true;
2445
2446 case Bytecodes::_aload:
2447 *index = itr->get_index();
2448 return true;
2449
2450 default:
2451 return false;
2452 }
2453 }
2454
2455
2456 // Return true iff the top of the operand stack holds a return address at
2457 // the current instruction
2458 bool GenerateOopMap::stack_top_holds_ret_addr(int bci) {
2459 for(int i = 0; i < _ret_adr_tos->length(); i++) {
2460 if (_ret_adr_tos->at(i) == bci)
2461 return true;
2462 }
2463
2464 return false;
2465 }
2466
2467 void GenerateOopMap::compute_ret_adr_at_TOS() {
2468 assert(_ret_adr_tos != nullptr, "must be initialized");
2469 _ret_adr_tos->clear();
2470
2471 for (int i = 0; i < bb_count(); i++) {
2472 BasicBlock* bb = &_basic_blocks[i];
2473
2474 // Make sure to only check basicblocks that are reachable
2475 if (bb->is_reachable()) {
2476
2477 // For each Basic block we check all instructions
2478 BytecodeStream bcs(_method);
2479 bcs.set_interval(bb->_bci, next_bb_start_pc(bb));
2480
2481 restore_state(bb);
2482
2483 while (bcs.next()>=0 && !_got_error) {
2484 // TDT: should this be is_good_address() ?
2485 if (_stack_top > 0 && stack()[_stack_top-1].is_address()) {
2486 _ret_adr_tos->append(bcs.bci());
2487 log_debug(generateoopmap)("Ret_adr TOS at bci: %d", bcs.bci());
2488 }
2489 interp1(&bcs);
2490 }
2491 }
2492 }
2493 }
2494
2495 void GenerateOopMap::update_ret_adr_at_TOS(int bci, int delta) {
2496 for(int i = 0; i < _ret_adr_tos->length(); i++) {
2497 int v = _ret_adr_tos->at(i);
2498 if (v > bci) _ret_adr_tos->at_put(i, v + delta);
2499 }
2500 }
2501
2502 // ===================================================================
2503
2504 #ifndef PRODUCT
2505 int ResolveOopMapConflicts::_nof_invocations = 0;
2506 int ResolveOopMapConflicts::_nof_rewrites = 0;
2507 int ResolveOopMapConflicts::_nof_relocations = 0;
2508 #endif
2509
2510 methodHandle ResolveOopMapConflicts::do_potential_rewrite(TRAPS) {
2511 if (!compute_map(THREAD)) {
2512 THROW_HANDLE_(exception(), methodHandle());
2513 }
2514
2515 #ifndef PRODUCT
2516 // Tracking and statistics
2517 if (PrintRewrites) {
2518 _nof_invocations++;
2519 if (did_rewriting()) {
2520 _nof_rewrites++;
2521 if (did_relocation()) _nof_relocations++;
2522 tty->print("Method was rewritten %s: ", (did_relocation()) ? "and relocated" : "");
2523 method()->print_value(); tty->cr();
2524 tty->print_cr("Cand.: %d rewrts: %d (%d%%) reloc.: %d (%d%%)",
2525 _nof_invocations,
2526 _nof_rewrites, (_nof_rewrites * 100) / _nof_invocations,
2527 _nof_relocations, (_nof_relocations * 100) / _nof_invocations);
2528 }
2529 }
2530 #endif
2531 return methodHandle(THREAD, method());
2532 }