1 /*
2 * Copyright (c) 1997, 2017, 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 "interpreter/bytecodeStream.hpp"
27 #include "logging/log.hpp"
28 #include "oops/generateOopMap.hpp"
29 #include "oops/oop.inline.hpp"
30 #include "oops/symbol.hpp"
31 #include "runtime/handles.inline.hpp"
32 #include "runtime/java.hpp"
33 #include "runtime/relocator.hpp"
34 #include "runtime/timerTrace.hpp"
35 #include "utilities/bitMap.inline.hpp"
36 #include "utilities/ostream.hpp"
37
38 //
39 //
40 // Compute stack layouts for each instruction in method.
41 //
42 // Problems:
43 // - What to do about jsr with different types of local vars?
44 // Need maps that are conditional on jsr path?
45 // - Jsr and exceptions should be done more efficiently (the retAddr stuff)
46 //
47 // Alternative:
48 // - Could extend verifier to provide this information.
49 // For: one fewer abstract interpreter to maintain. Against: the verifier
50 // solves a bigger problem so slower (undesirable to force verification of
51 // everything?).
52 //
53 // Algorithm:
54 // Partition bytecodes into basic blocks
55 // For each basic block: store entry state (vars, stack). For instructions
56 // inside basic blocks we do not store any state (instead we recompute it
57 // from state produced by previous instruction).
58 //
59 // Perform abstract interpretation of bytecodes over this lattice:
60 //
61 // _--'#'--_
62 // / / \ \
63 // / / \ \
64 // / | | \
65 // 'r' 'v' 'p' ' '
66 // \ | | /
67 // \ \ / /
68 // \ \ / /
69 // -- '@' --
70 //
71 // '#' top, result of conflict merge
72 // 'r' reference type
73 // 'v' value type
74 // 'p' pc type for jsr/ret
75 // ' ' uninitialized; never occurs on operand stack in Java
76 // '@' bottom/unexecuted; initial state each bytecode.
77 //
78 // Basic block headers are the only merge points. We use this iteration to
79 // compute the information:
80 //
81 // find basic blocks;
82 // initialize them with uninitialized state;
83 // initialize first BB according to method signature;
84 // mark first BB changed
85 // while (some BB is changed) do {
86 // perform abstract interpration of all bytecodes in BB;
87 // merge exit state of BB into entry state of all successor BBs,
88 // noting if any of these change;
89 // }
90 //
91 // One additional complication is necessary. The jsr instruction pushes
92 // a return PC on the stack (a 'p' type in the abstract interpretation).
93 // To be able to process "ret" bytecodes, we keep track of these return
94 // PC's in a 'retAddrs' structure in abstract interpreter context (when
95 // processing a "ret" bytecodes, it is not sufficient to know that it gets
96 // an argument of the right type 'p'; we need to know which address it
97 // returns to).
98 //
99 // (Note this comment is borrowed form the original author of the algorithm)
100
101 // ComputeCallStack
102 //
103 // Specialization of SignatureIterator - compute the effects of a call
104 //
105 class ComputeCallStack : public SignatureIterator {
106 CellTypeState *_effect;
107 int _idx;
108
109 void setup();
110 void set(CellTypeState state) { _effect[_idx++] = state; }
111 int length() { return _idx; };
112
113 virtual void do_bool () { set(CellTypeState::value); };
114 virtual void do_char () { set(CellTypeState::value); };
115 virtual void do_float () { set(CellTypeState::value); };
116 virtual void do_byte () { set(CellTypeState::value); };
117 virtual void do_short () { set(CellTypeState::value); };
118 virtual void do_int () { set(CellTypeState::value); };
119 virtual void do_void () { set(CellTypeState::bottom);};
120 virtual void do_object(int begin, int end) { set(CellTypeState::ref); };
121 virtual void do_array (int begin, int end) { set(CellTypeState::ref); };
122
123 void do_double() { set(CellTypeState::value);
124 set(CellTypeState::value); }
125 void do_long () { set(CellTypeState::value);
126 set(CellTypeState::value); }
127
128 public:
129 ComputeCallStack(Symbol* signature) : SignatureIterator(signature) {};
130
131 // Compute methods
132 int compute_for_parameters(bool is_static, CellTypeState *effect) {
133 _idx = 0;
134 _effect = effect;
135
136 if (!is_static)
137 effect[_idx++] = CellTypeState::ref;
138
139 iterate_parameters();
140
141 return length();
142 };
143
144 int compute_for_returntype(CellTypeState *effect) {
145 _idx = 0;
146 _effect = effect;
147 iterate_returntype();
148 set(CellTypeState::bottom); // Always terminate with a bottom state, so ppush works
149
150 return length();
151 }
152 };
153
154 //=========================================================================================
155 // ComputeEntryStack
156 //
157 // Specialization of SignatureIterator - in order to set up first stack frame
158 //
159 class ComputeEntryStack : public SignatureIterator {
160 CellTypeState *_effect;
161 int _idx;
162
163 void setup();
164 void set(CellTypeState state) { _effect[_idx++] = state; }
165 int length() { return _idx; };
166
167 virtual void do_bool () { set(CellTypeState::value); };
168 virtual void do_char () { set(CellTypeState::value); };
169 virtual void do_float () { set(CellTypeState::value); };
170 virtual void do_byte () { set(CellTypeState::value); };
171 virtual void do_short () { set(CellTypeState::value); };
172 virtual void do_int () { set(CellTypeState::value); };
173 virtual void do_void () { set(CellTypeState::bottom);};
174 virtual void do_object(int begin, int end) { set(CellTypeState::make_slot_ref(_idx)); }
175 virtual void do_array (int begin, int end) { set(CellTypeState::make_slot_ref(_idx)); }
176
177 void do_double() { set(CellTypeState::value);
178 set(CellTypeState::value); }
179 void do_long () { set(CellTypeState::value);
180 set(CellTypeState::value); }
181
182 public:
183 ComputeEntryStack(Symbol* signature) : SignatureIterator(signature) {};
184
185 // Compute methods
186 int compute_for_parameters(bool is_static, CellTypeState *effect) {
187 _idx = 0;
188 _effect = effect;
189
190 if (!is_static)
191 effect[_idx++] = CellTypeState::make_slot_ref(0);
192
193 iterate_parameters();
194
195 return length();
196 };
197
198 int compute_for_returntype(CellTypeState *effect) {
199 _idx = 0;
200 _effect = effect;
201 iterate_returntype();
202 set(CellTypeState::bottom); // Always terminate with a bottom state, so ppush works
203
204 return length();
205 }
206 };
207
208 //=====================================================================================
209 //
210 // Implementation of RetTable/RetTableEntry
211 //
212 // Contains function to itereate through all bytecodes
213 // and find all return entry points
214 //
215 int RetTable::_init_nof_entries = 10;
216 int RetTableEntry::_init_nof_jsrs = 5;
217
218 void RetTableEntry::add_delta(int bci, int delta) {
219 if (_target_bci > bci) _target_bci += delta;
220
221 for (int k = 0; k < _jsrs->length(); k++) {
222 int jsr = _jsrs->at(k);
223 if (jsr > bci) _jsrs->at_put(k, jsr+delta);
224 }
225 }
226
227 void RetTable::compute_ret_table(const methodHandle& method) {
228 BytecodeStream i(method);
229 Bytecodes::Code bytecode;
230
231 while( (bytecode = i.next()) >= 0) {
232 switch (bytecode) {
233 case Bytecodes::_jsr:
234 add_jsr(i.next_bci(), i.dest());
235 break;
236 case Bytecodes::_jsr_w:
237 add_jsr(i.next_bci(), i.dest_w());
238 break;
239 }
240 }
241 }
242
243 void RetTable::add_jsr(int return_bci, int target_bci) {
244 RetTableEntry* entry = _first;
245
246 // Scan table for entry
247 for (;entry && entry->target_bci() != target_bci; entry = entry->next());
248
249 if (!entry) {
250 // Allocate new entry and put in list
251 entry = new RetTableEntry(target_bci, _first);
252 _first = entry;
253 }
254
255 // Now "entry" is set. Make sure that the entry is initialized
256 // and has room for the new jsr.
257 entry->add_jsr(return_bci);
258 }
259
260 RetTableEntry* RetTable::find_jsrs_for_target(int targBci) {
261 RetTableEntry *cur = _first;
262
263 while(cur) {
264 assert(cur->target_bci() != -1, "sanity check");
265 if (cur->target_bci() == targBci) return cur;
266 cur = cur->next();
267 }
268 ShouldNotReachHere();
269 return NULL;
270 }
271
272 // The instruction at bci is changing size by "delta". Update the return map.
273 void RetTable::update_ret_table(int bci, int delta) {
274 RetTableEntry *cur = _first;
275 while(cur) {
276 cur->add_delta(bci, delta);
277 cur = cur->next();
278 }
279 }
280
281 //
282 // Celltype state
283 //
284
285 CellTypeState CellTypeState::bottom = CellTypeState::make_bottom();
286 CellTypeState CellTypeState::uninit = CellTypeState::make_any(uninit_value);
287 CellTypeState CellTypeState::ref = CellTypeState::make_any(ref_conflict);
288 CellTypeState CellTypeState::value = CellTypeState::make_any(val_value);
289 CellTypeState CellTypeState::refUninit = CellTypeState::make_any(ref_conflict | uninit_value);
290 CellTypeState CellTypeState::top = CellTypeState::make_top();
291 CellTypeState CellTypeState::addr = CellTypeState::make_any(addr_conflict);
292
293 // Commonly used constants
294 static CellTypeState epsilonCTS[1] = { CellTypeState::bottom };
295 static CellTypeState refCTS = CellTypeState::ref;
296 static CellTypeState valCTS = CellTypeState::value;
297 static CellTypeState vCTS[2] = { CellTypeState::value, CellTypeState::bottom };
298 static CellTypeState rCTS[2] = { CellTypeState::ref, CellTypeState::bottom };
299 static CellTypeState rrCTS[3] = { CellTypeState::ref, CellTypeState::ref, CellTypeState::bottom };
300 static CellTypeState vrCTS[3] = { CellTypeState::value, CellTypeState::ref, CellTypeState::bottom };
301 static CellTypeState vvCTS[3] = { CellTypeState::value, CellTypeState::value, CellTypeState::bottom };
302 static CellTypeState rvrCTS[4] = { CellTypeState::ref, CellTypeState::value, CellTypeState::ref, CellTypeState::bottom };
303 static CellTypeState vvrCTS[4] = { CellTypeState::value, CellTypeState::value, CellTypeState::ref, CellTypeState::bottom };
304 static CellTypeState vvvCTS[4] = { CellTypeState::value, CellTypeState::value, CellTypeState::value, CellTypeState::bottom };
305 static CellTypeState vvvrCTS[5] = { CellTypeState::value, CellTypeState::value, CellTypeState::value, CellTypeState::ref, CellTypeState::bottom };
306 static CellTypeState vvvvCTS[5] = { CellTypeState::value, CellTypeState::value, CellTypeState::value, CellTypeState::value, CellTypeState::bottom };
307
308 char CellTypeState::to_char() const {
309 if (can_be_reference()) {
310 if (can_be_value() || can_be_address())
311 return '#'; // Conflict that needs to be rewritten
312 else
313 return 'r';
314 } else if (can_be_value())
315 return 'v';
316 else if (can_be_address())
317 return 'p';
318 else if (can_be_uninit())
319 return ' ';
320 else
321 return '@';
322 }
323
324
325 // Print a detailed CellTypeState. Indicate all bits that are set. If
326 // the CellTypeState represents an address or a reference, print the
327 // value of the additional information.
328 void CellTypeState::print(outputStream *os) {
329 if (can_be_address()) {
330 os->print("(p");
331 } else {
332 os->print("( ");
333 }
334 if (can_be_reference()) {
335 os->print("r");
336 } else {
337 os->print(" ");
338 }
339 if (can_be_value()) {
340 os->print("v");
341 } else {
342 os->print(" ");
343 }
344 if (can_be_uninit()) {
345 os->print("u|");
346 } else {
347 os->print(" |");
348 }
349 if (is_info_top()) {
350 os->print("Top)");
351 } else if (is_info_bottom()) {
352 os->print("Bot)");
353 } else {
354 if (is_reference()) {
355 int info = get_info();
356 int data = info & ~(ref_not_lock_bit | ref_slot_bit);
357 if (info & ref_not_lock_bit) {
358 // Not a monitor lock reference.
359 if (info & ref_slot_bit) {
360 // slot
361 os->print("slot%d)", data);
362 } else {
363 // line
364 os->print("line%d)", data);
365 }
366 } else {
367 // lock
368 os->print("lock%d)", data);
369 }
370 } else {
371 os->print("%d)", get_info());
372 }
373 }
374 }
375
376 //
377 // Basicblock handling methods
378 //
379
380 void GenerateOopMap::initialize_bb() {
381 _gc_points = 0;
382 _bb_count = 0;
383 _bb_hdr_bits.reinitialize(method()->code_size());
384 }
385
386 void GenerateOopMap::bb_mark_fct(GenerateOopMap *c, int bci, int *data) {
387 assert(bci>= 0 && bci < c->method()->code_size(), "index out of bounds");
388 if (c->is_bb_header(bci))
389 return;
390
391 if (TraceNewOopMapGeneration) {
392 tty->print_cr("Basicblock#%d begins at: %d", c->_bb_count, bci);
393 }
394 c->set_bbmark_bit(bci);
395 c->_bb_count++;
396 }
397
398
399 void GenerateOopMap::mark_bbheaders_and_count_gc_points() {
400 initialize_bb();
401
402 bool fellThrough = false; // False to get first BB marked.
403
404 // First mark all exception handlers as start of a basic-block
405 ExceptionTable excps(method());
406 for(int i = 0; i < excps.length(); i ++) {
407 bb_mark_fct(this, excps.handler_pc(i), NULL);
408 }
409
410 // Then iterate through the code
411 BytecodeStream bcs(_method);
412 Bytecodes::Code bytecode;
413
414 while( (bytecode = bcs.next()) >= 0) {
415 int bci = bcs.bci();
416
417 if (!fellThrough)
418 bb_mark_fct(this, bci, NULL);
419
420 fellThrough = jump_targets_do(&bcs, &GenerateOopMap::bb_mark_fct, NULL);
421
422 /* We will also mark successors of jsr's as basic block headers. */
423 switch (bytecode) {
424 case Bytecodes::_jsr:
425 assert(!fellThrough, "should not happen");
426 bb_mark_fct(this, bci + Bytecodes::length_for(bytecode), NULL);
427 break;
428 case Bytecodes::_jsr_w:
429 assert(!fellThrough, "should not happen");
430 bb_mark_fct(this, bci + Bytecodes::length_for(bytecode), NULL);
431 break;
432 }
433
434 if (possible_gc_point(&bcs))
435 _gc_points++;
436 }
437 }
438
439 void GenerateOopMap::set_bbmark_bit(int bci) {
440 _bb_hdr_bits.at_put(bci, true);
441 }
442
443 void GenerateOopMap::reachable_basicblock(GenerateOopMap *c, int bci, int *data) {
444 assert(bci>= 0 && bci < c->method()->code_size(), "index out of bounds");
445 BasicBlock* bb = c->get_basic_block_at(bci);
446 if (bb->is_dead()) {
447 bb->mark_as_alive();
448 *data = 1; // Mark basicblock as changed
449 }
450 }
451
452
453 void GenerateOopMap::mark_reachable_code() {
454 int change = 1; // int to get function pointers to work
455
456 // Mark entry basic block as alive and all exception handlers
457 _basic_blocks[0].mark_as_alive();
458 ExceptionTable excps(method());
459 for(int i = 0; i < excps.length(); i++) {
460 BasicBlock *bb = get_basic_block_at(excps.handler_pc(i));
461 // If block is not already alive (due to multiple exception handlers to same bb), then
462 // make it alive
463 if (bb->is_dead()) bb->mark_as_alive();
464 }
465
466 BytecodeStream bcs(_method);
467
468 // Iterate through all basic blocks until we reach a fixpoint
469 while (change) {
470 change = 0;
471
472 for (int i = 0; i < _bb_count; i++) {
473 BasicBlock *bb = &_basic_blocks[i];
474 if (bb->is_alive()) {
475 // Position bytecodestream at last bytecode in basicblock
476 bcs.set_start(bb->_end_bci);
477 bcs.next();
478 Bytecodes::Code bytecode = bcs.code();
479 int bci = bcs.bci();
480 assert(bci == bb->_end_bci, "wrong bci");
481
482 bool fell_through = jump_targets_do(&bcs, &GenerateOopMap::reachable_basicblock, &change);
483
484 // We will also mark successors of jsr's as alive.
485 switch (bytecode) {
486 case Bytecodes::_jsr:
487 case Bytecodes::_jsr_w:
488 assert(!fell_through, "should not happen");
489 reachable_basicblock(this, bci + Bytecodes::length_for(bytecode), &change);
490 break;
491 }
492 if (fell_through) {
493 // Mark successor as alive
494 if (bb[1].is_dead()) {
495 bb[1].mark_as_alive();
496 change = 1;
497 }
498 }
499 }
500 }
501 }
502 }
503
504 /* If the current instruction in "c" has no effect on control flow,
505 returns "true". Otherwise, calls "jmpFct" one or more times, with
506 "c", an appropriate "pcDelta", and "data" as arguments, then
507 returns "false". There is one exception: if the current
508 instruction is a "ret", returns "false" without calling "jmpFct".
509 Arrangements for tracking the control flow of a "ret" must be made
510 externally. */
511 bool GenerateOopMap::jump_targets_do(BytecodeStream *bcs, jmpFct_t jmpFct, int *data) {
512 int bci = bcs->bci();
513
514 switch (bcs->code()) {
515 case Bytecodes::_ifeq:
516 case Bytecodes::_ifne:
517 case Bytecodes::_iflt:
518 case Bytecodes::_ifge:
519 case Bytecodes::_ifgt:
520 case Bytecodes::_ifle:
521 case Bytecodes::_if_icmpeq:
522 case Bytecodes::_if_icmpne:
523 case Bytecodes::_if_icmplt:
524 case Bytecodes::_if_icmpge:
525 case Bytecodes::_if_icmpgt:
526 case Bytecodes::_if_icmple:
527 case Bytecodes::_if_acmpeq:
528 case Bytecodes::_if_acmpne:
529 case Bytecodes::_ifnull:
530 case Bytecodes::_ifnonnull:
531 (*jmpFct)(this, bcs->dest(), data);
532 (*jmpFct)(this, bci + 3, data);
533 break;
534
535 case Bytecodes::_goto:
536 (*jmpFct)(this, bcs->dest(), data);
537 break;
538 case Bytecodes::_goto_w:
539 (*jmpFct)(this, bcs->dest_w(), data);
540 break;
541 case Bytecodes::_tableswitch:
542 { Bytecode_tableswitch tableswitch(method(), bcs->bcp());
543 int len = tableswitch.length();
544
545 (*jmpFct)(this, bci + tableswitch.default_offset(), data); /* Default. jump address */
546 while (--len >= 0) {
547 (*jmpFct)(this, bci + tableswitch.dest_offset_at(len), data);
548 }
549 break;
550 }
551
552 case Bytecodes::_lookupswitch:
553 { Bytecode_lookupswitch lookupswitch(method(), bcs->bcp());
554 int npairs = lookupswitch.number_of_pairs();
555 (*jmpFct)(this, bci + lookupswitch.default_offset(), data); /* Default. */
556 while(--npairs >= 0) {
557 LookupswitchPair pair = lookupswitch.pair_at(npairs);
558 (*jmpFct)(this, bci + pair.offset(), data);
559 }
560 break;
561 }
562 case Bytecodes::_jsr:
563 assert(bcs->is_wide()==false, "sanity check");
564 (*jmpFct)(this, bcs->dest(), data);
565
566
567
568 break;
569 case Bytecodes::_jsr_w:
570 (*jmpFct)(this, bcs->dest_w(), data);
571 break;
572 case Bytecodes::_wide:
573 ShouldNotReachHere();
574 return true;
575 break;
576 case Bytecodes::_athrow:
577 case Bytecodes::_ireturn:
578 case Bytecodes::_lreturn:
579 case Bytecodes::_freturn:
580 case Bytecodes::_dreturn:
581 case Bytecodes::_areturn:
582 case Bytecodes::_return:
583 case Bytecodes::_ret:
584 break;
585 default:
586 return true;
587 }
588 return false;
589 }
590
591 /* Requires "pc" to be the head of a basic block; returns that basic
592 block. */
593 BasicBlock *GenerateOopMap::get_basic_block_at(int bci) const {
594 BasicBlock* bb = get_basic_block_containing(bci);
595 assert(bb->_bci == bci, "should have found BB");
596 return bb;
597 }
598
599 // Requires "pc" to be the start of an instruction; returns the basic
600 // block containing that instruction. */
601 BasicBlock *GenerateOopMap::get_basic_block_containing(int bci) const {
602 BasicBlock *bbs = _basic_blocks;
603 int lo = 0, hi = _bb_count - 1;
604
605 while (lo <= hi) {
606 int m = (lo + hi) / 2;
607 int mbci = bbs[m]._bci;
608 int nbci;
609
610 if ( m == _bb_count-1) {
611 assert( bci >= mbci && bci < method()->code_size(), "sanity check failed");
612 return bbs+m;
613 } else {
614 nbci = bbs[m+1]._bci;
615 }
616
617 if ( mbci <= bci && bci < nbci) {
618 return bbs+m;
619 } else if (mbci < bci) {
620 lo = m + 1;
621 } else {
622 assert(mbci > bci, "sanity check");
623 hi = m - 1;
624 }
625 }
626
627 fatal("should have found BB");
628 return NULL;
629 }
630
631 void GenerateOopMap::restore_state(BasicBlock *bb)
632 {
633 memcpy(_state, bb->_state, _state_len*sizeof(CellTypeState));
634 _stack_top = bb->_stack_top;
635 _monitor_top = bb->_monitor_top;
636 }
637
638 int GenerateOopMap::next_bb_start_pc(BasicBlock *bb) {
639 int bbNum = bb - _basic_blocks + 1;
640 if (bbNum == _bb_count)
641 return method()->code_size();
642
643 return _basic_blocks[bbNum]._bci;
644 }
645
646 //
647 // CellType handling methods
648 //
649
650 // Allocate memory and throw LinkageError if failure.
651 #define ALLOC_RESOURCE_ARRAY(var, type, count) \
652 var = NEW_RESOURCE_ARRAY_RETURN_NULL(type, count); \
653 if (var == NULL) { \
654 report_error("Cannot reserve enough memory to analyze this method"); \
655 return; \
656 }
657
658
659 void GenerateOopMap::init_state() {
660 _state_len = _max_locals + _max_stack + _max_monitors;
661 ALLOC_RESOURCE_ARRAY(_state, CellTypeState, _state_len);
662 memset(_state, 0, _state_len * sizeof(CellTypeState));
663 int count = MAX3(_max_locals, _max_stack, _max_monitors) + 1/*for null terminator char */;
664 ALLOC_RESOURCE_ARRAY(_state_vec_buf, char, count);
665 }
666
667 void GenerateOopMap::make_context_uninitialized() {
668 CellTypeState* vs = vars();
669
670 for (int i = 0; i < _max_locals; i++)
671 vs[i] = CellTypeState::uninit;
672
673 _stack_top = 0;
674 _monitor_top = 0;
675 }
676
677 int GenerateOopMap::methodsig_to_effect(Symbol* signature, bool is_static, CellTypeState* effect) {
678 ComputeEntryStack ces(signature);
679 return ces.compute_for_parameters(is_static, effect);
680 }
681
682 // Return result of merging cts1 and cts2.
683 CellTypeState CellTypeState::merge(CellTypeState cts, int slot) const {
684 CellTypeState result;
685
686 assert(!is_bottom() && !cts.is_bottom(),
687 "merge of bottom values is handled elsewhere");
688
689 result._state = _state | cts._state;
690
691 // If the top bit is set, we don't need to do any more work.
692 if (!result.is_info_top()) {
693 assert((result.can_be_address() || result.can_be_reference()),
694 "only addresses and references have non-top info");
695
696 if (!equal(cts)) {
697 // The two values being merged are different. Raise to top.
698 if (result.is_reference()) {
699 result = CellTypeState::make_slot_ref(slot);
700 } else {
701 result._state |= info_conflict;
702 }
703 }
704 }
705 assert(result.is_valid_state(), "checking that CTS merge maintains legal state");
706
707 return result;
708 }
709
710 // Merge the variable state for locals and stack from cts into bbts.
711 bool GenerateOopMap::merge_local_state_vectors(CellTypeState* cts,
712 CellTypeState* bbts) {
713 int i;
714 int len = _max_locals + _stack_top;
715 bool change = false;
716
717 for (i = len - 1; i >= 0; i--) {
718 CellTypeState v = cts[i].merge(bbts[i], i);
719 change = change || !v.equal(bbts[i]);
720 bbts[i] = v;
721 }
722
723 return change;
724 }
725
726 // Merge the monitor stack state from cts into bbts.
727 bool GenerateOopMap::merge_monitor_state_vectors(CellTypeState* cts,
728 CellTypeState* bbts) {
729 bool change = false;
730 if (_max_monitors > 0 && _monitor_top != bad_monitors) {
731 // If there are no monitors in the program, or there has been
732 // a monitor matching error before this point in the program,
733 // then we do not merge in the monitor state.
734
735 int base = _max_locals + _max_stack;
736 int len = base + _monitor_top;
737 for (int i = len - 1; i >= base; i--) {
738 CellTypeState v = cts[i].merge(bbts[i], i);
739
740 // Can we prove that, when there has been a change, it will already
741 // have been detected at this point? That would make this equal
742 // check here unnecessary.
743 change = change || !v.equal(bbts[i]);
744 bbts[i] = v;
745 }
746 }
747
748 return change;
749 }
750
751 void GenerateOopMap::copy_state(CellTypeState *dst, CellTypeState *src) {
752 int len = _max_locals + _stack_top;
753 for (int i = 0; i < len; i++) {
754 if (src[i].is_nonlock_reference()) {
755 dst[i] = CellTypeState::make_slot_ref(i);
756 } else {
757 dst[i] = src[i];
758 }
759 }
760 if (_max_monitors > 0 && _monitor_top != bad_monitors) {
761 int base = _max_locals + _max_stack;
762 len = base + _monitor_top;
763 for (int i = base; i < len; i++) {
764 dst[i] = src[i];
765 }
766 }
767 }
768
769
770 // Merge the states for the current block and the next. As long as a
771 // block is reachable the locals and stack must be merged. If the
772 // stack heights don't match then this is a verification error and
773 // it's impossible to interpret the code. Simultaneously monitor
774 // states are being check to see if they nest statically. If monitor
775 // depths match up then their states are merged. Otherwise the
776 // mismatch is simply recorded and interpretation continues since
777 // monitor matching is purely informational and doesn't say anything
778 // about the correctness of the code.
779 void GenerateOopMap::merge_state_into_bb(BasicBlock *bb) {
780 guarantee(bb != NULL, "null basicblock");
781 assert(bb->is_alive(), "merging state into a dead basicblock");
782
783 if (_stack_top == bb->_stack_top) {
784 // always merge local state even if monitors don't match.
785 if (merge_local_state_vectors(_state, bb->_state)) {
786 bb->set_changed(true);
787 }
788 if (_monitor_top == bb->_monitor_top) {
789 // monitors still match so continue merging monitor states.
790 if (merge_monitor_state_vectors(_state, bb->_state)) {
791 bb->set_changed(true);
792 }
793 } else {
794 if (log_is_enabled(Info, monitormismatch)) {
795 report_monitor_mismatch("monitor stack height merge conflict");
796 }
797 // When the monitor stacks are not matched, we set _monitor_top to
798 // bad_monitors. This signals that, from here on, the monitor stack cannot
799 // be trusted. In particular, monitorexit bytecodes may throw
800 // exceptions. We mark this block as changed so that the change
801 // propagates properly.
802 bb->_monitor_top = bad_monitors;
803 bb->set_changed(true);
804 _monitor_safe = false;
805 }
806 } else if (!bb->is_reachable()) {
807 // First time we look at this BB
808 copy_state(bb->_state, _state);
809 bb->_stack_top = _stack_top;
810 bb->_monitor_top = _monitor_top;
811 bb->set_changed(true);
812 } else {
813 verify_error("stack height conflict: %d vs. %d", _stack_top, bb->_stack_top);
814 }
815 }
816
817 void GenerateOopMap::merge_state(GenerateOopMap *gom, int bci, int* data) {
818 gom->merge_state_into_bb(gom->get_basic_block_at(bci));
819 }
820
821 void GenerateOopMap::set_var(int localNo, CellTypeState cts) {
822 assert(cts.is_reference() || cts.is_value() || cts.is_address(),
823 "wrong celltypestate");
824 if (localNo < 0 || localNo > _max_locals) {
825 verify_error("variable write error: r%d", localNo);
826 return;
827 }
828 vars()[localNo] = cts;
829 }
830
831 CellTypeState GenerateOopMap::get_var(int localNo) {
832 assert(localNo < _max_locals + _nof_refval_conflicts, "variable read error");
833 if (localNo < 0 || localNo > _max_locals) {
834 verify_error("variable read error: r%d", localNo);
835 return valCTS; // just to pick something;
836 }
837 return vars()[localNo];
838 }
839
840 CellTypeState GenerateOopMap::pop() {
841 if ( _stack_top <= 0) {
842 verify_error("stack underflow");
843 return valCTS; // just to pick something
844 }
845 return stack()[--_stack_top];
846 }
847
848 void GenerateOopMap::push(CellTypeState cts) {
849 if ( _stack_top >= _max_stack) {
850 verify_error("stack overflow");
851 return;
852 }
853 stack()[_stack_top++] = cts;
854 }
855
856 CellTypeState GenerateOopMap::monitor_pop() {
857 assert(_monitor_top != bad_monitors, "monitor_pop called on error monitor stack");
858 if (_monitor_top == 0) {
859 // We have detected a pop of an empty monitor stack.
860 _monitor_safe = false;
861 _monitor_top = bad_monitors;
862
863 if (log_is_enabled(Info, monitormismatch)) {
864 report_monitor_mismatch("monitor stack underflow");
865 }
866 return CellTypeState::ref; // just to keep the analysis going.
867 }
868 return monitors()[--_monitor_top];
869 }
870
871 void GenerateOopMap::monitor_push(CellTypeState cts) {
872 assert(_monitor_top != bad_monitors, "monitor_push called on error monitor stack");
873 if (_monitor_top >= _max_monitors) {
874 // Some monitorenter is being executed more than once.
875 // This means that the monitor stack cannot be simulated.
876 _monitor_safe = false;
877 _monitor_top = bad_monitors;
878
879 if (log_is_enabled(Info, monitormismatch)) {
880 report_monitor_mismatch("monitor stack overflow");
881 }
882 return;
883 }
884 monitors()[_monitor_top++] = cts;
885 }
886
887 //
888 // Interpretation handling methods
889 //
890
891 void GenerateOopMap::do_interpretation()
892 {
893 // "i" is just for debugging, so we can detect cases where this loop is
894 // iterated more than once.
895 int i = 0;
896 do {
897 #ifndef PRODUCT
898 if (TraceNewOopMapGeneration) {
899 tty->print("\n\nIteration #%d of do_interpretation loop, method:\n", i);
900 method()->print_name(tty);
901 tty->print("\n\n");
902 }
903 #endif
904 _conflict = false;
905 _monitor_safe = true;
906 // init_state is now called from init_basic_blocks. The length of a
907 // state vector cannot be determined until we have made a pass through
908 // the bytecodes counting the possible monitor entries.
909 if (!_got_error) init_basic_blocks();
910 if (!_got_error) setup_method_entry_state();
911 if (!_got_error) interp_all();
912 if (!_got_error) rewrite_refval_conflicts();
913 i++;
914 } while (_conflict && !_got_error);
915 }
916
917 void GenerateOopMap::init_basic_blocks() {
918 // Note: Could consider reserving only the needed space for each BB's state
919 // (entry stack may not be of maximal height for every basic block).
920 // But cumbersome since we don't know the stack heights yet. (Nor the
921 // monitor stack heights...)
922
923 ALLOC_RESOURCE_ARRAY(_basic_blocks, BasicBlock, _bb_count);
924
925 // Make a pass through the bytecodes. Count the number of monitorenters.
926 // This can be used an upper bound on the monitor stack depth in programs
927 // which obey stack discipline with their monitor usage. Initialize the
928 // known information about basic blocks.
929 BytecodeStream j(_method);
930 Bytecodes::Code bytecode;
931
932 int bbNo = 0;
933 int monitor_count = 0;
934 int prev_bci = -1;
935 while( (bytecode = j.next()) >= 0) {
936 if (j.code() == Bytecodes::_monitorenter) {
937 monitor_count++;
938 }
939
940 int bci = j.bci();
941 if (is_bb_header(bci)) {
942 // Initialize the basicblock structure
943 BasicBlock *bb = _basic_blocks + bbNo;
944 bb->_bci = bci;
945 bb->_max_locals = _max_locals;
946 bb->_max_stack = _max_stack;
947 bb->set_changed(false);
948 bb->_stack_top = BasicBlock::_dead_basic_block; // Initialize all basicblocks are dead.
949 bb->_monitor_top = bad_monitors;
950
951 if (bbNo > 0) {
952 _basic_blocks[bbNo - 1]._end_bci = prev_bci;
953 }
954
955 bbNo++;
956 }
957 // Remember prevous bci.
958 prev_bci = bci;
959 }
960 // Set
961 _basic_blocks[bbNo-1]._end_bci = prev_bci;
962
963
964 // Check that the correct number of basicblocks was found
965 if (bbNo !=_bb_count) {
966 if (bbNo < _bb_count) {
967 verify_error("jump into the middle of instruction?");
968 return;
969 } else {
970 verify_error("extra basic blocks - should not happen?");
971 return;
972 }
973 }
974
975 _max_monitors = monitor_count;
976
977 // Now that we have a bound on the depth of the monitor stack, we can
978 // initialize the CellTypeState-related information.
979 init_state();
980
981 // We allocate space for all state-vectors for all basicblocks in one huge
982 // chunk. Then in the next part of the code, we set a pointer in each
983 // _basic_block that points to each piece.
984
985 // The product of bbNo and _state_len can get large if there are lots of
986 // basic blocks and stack/locals/monitors. Need to check to make sure
987 // we don't overflow the capacity of a pointer.
988 if ((unsigned)bbNo > UINTPTR_MAX / sizeof(CellTypeState) / _state_len) {
989 report_error("The amount of memory required to analyze this method "
990 "exceeds addressable range");
991 return;
992 }
993
994 CellTypeState *basicBlockState;
995 ALLOC_RESOURCE_ARRAY(basicBlockState, CellTypeState, bbNo * _state_len);
996 memset(basicBlockState, 0, bbNo * _state_len * sizeof(CellTypeState));
997
998 // Make a pass over the basicblocks and assign their state vectors.
999 for (int blockNum=0; blockNum < bbNo; blockNum++) {
1000 BasicBlock *bb = _basic_blocks + blockNum;
1001 bb->_state = basicBlockState + blockNum * _state_len;
1002
1003 #ifdef ASSERT
1004 if (blockNum + 1 < bbNo) {
1005 address bcp = _method->bcp_from(bb->_end_bci);
1006 int bc_len = Bytecodes::java_length_at(_method(), bcp);
1007 assert(bb->_end_bci + bc_len == bb[1]._bci, "unmatched bci info in basicblock");
1008 }
1009 #endif
1010 }
1011 #ifdef ASSERT
1012 { BasicBlock *bb = &_basic_blocks[bbNo-1];
1013 address bcp = _method->bcp_from(bb->_end_bci);
1014 int bc_len = Bytecodes::java_length_at(_method(), bcp);
1015 assert(bb->_end_bci + bc_len == _method->code_size(), "wrong end bci");
1016 }
1017 #endif
1018
1019 // Mark all alive blocks
1020 mark_reachable_code();
1021 }
1022
1023 void GenerateOopMap::setup_method_entry_state() {
1024
1025 // Initialize all locals to 'uninit' and set stack-height to 0
1026 make_context_uninitialized();
1027
1028 // Initialize CellState type of arguments
1029 methodsig_to_effect(method()->signature(), method()->is_static(), vars());
1030
1031 // If some references must be pre-assigned to null, then set that up
1032 initialize_vars();
1033
1034 // This is the start state
1035 merge_state_into_bb(&_basic_blocks[0]);
1036
1037 assert(_basic_blocks[0].changed(), "we are not getting off the ground");
1038 }
1039
1040 // The instruction at bci is changing size by "delta". Update the basic blocks.
1041 void GenerateOopMap::update_basic_blocks(int bci, int delta,
1042 int new_method_size) {
1043 assert(new_method_size >= method()->code_size() + delta,
1044 "new method size is too small");
1045
1046 _bb_hdr_bits.reinitialize(new_method_size);
1047
1048 for(int k = 0; k < _bb_count; k++) {
1049 if (_basic_blocks[k]._bci > bci) {
1050 _basic_blocks[k]._bci += delta;
1051 _basic_blocks[k]._end_bci += delta;
1052 }
1053 _bb_hdr_bits.at_put(_basic_blocks[k]._bci, true);
1054 }
1055 }
1056
1057 //
1058 // Initvars handling
1059 //
1060
1061 void GenerateOopMap::initialize_vars() {
1062 for (int k = 0; k < _init_vars->length(); k++)
1063 _state[_init_vars->at(k)] = CellTypeState::make_slot_ref(k);
1064 }
1065
1066 void GenerateOopMap::add_to_ref_init_set(int localNo) {
1067
1068 if (TraceNewOopMapGeneration)
1069 tty->print_cr("Added init vars: %d", localNo);
1070
1071 // Is it already in the set?
1072 if (_init_vars->contains(localNo) )
1073 return;
1074
1075 _init_vars->append(localNo);
1076 }
1077
1078 //
1079 // Interpreration code
1080 //
1081
1082 void GenerateOopMap::interp_all() {
1083 bool change = true;
1084
1085 while (change && !_got_error) {
1086 change = false;
1087 for (int i = 0; i < _bb_count && !_got_error; i++) {
1088 BasicBlock *bb = &_basic_blocks[i];
1089 if (bb->changed()) {
1090 if (_got_error) return;
1091 change = true;
1092 bb->set_changed(false);
1093 interp_bb(bb);
1094 }
1095 }
1096 }
1097 }
1098
1099 void GenerateOopMap::interp_bb(BasicBlock *bb) {
1100
1101 // We do not want to do anything in case the basic-block has not been initialized. This
1102 // will happen in the case where there is dead-code hang around in a method.
1103 assert(bb->is_reachable(), "should be reachable or deadcode exist");
1104 restore_state(bb);
1105
1106 BytecodeStream itr(_method);
1107
1108 // Set iterator interval to be the current basicblock
1109 int lim_bci = next_bb_start_pc(bb);
1110 itr.set_interval(bb->_bci, lim_bci);
1111 assert(lim_bci != bb->_bci, "must be at least one instruction in a basicblock");
1112 itr.next(); // read first instruction
1113
1114 // Iterates through all bytecodes except the last in a basic block.
1115 // We handle the last one special, since there is controlflow change.
1116 while(itr.next_bci() < lim_bci && !_got_error) {
1117 if (_has_exceptions || _monitor_top != 0) {
1118 // We do not need to interpret the results of exceptional
1119 // continuation from this instruction when the method has no
1120 // exception handlers and the monitor stack is currently
1121 // empty.
1122 do_exception_edge(&itr);
1123 }
1124 interp1(&itr);
1125 itr.next();
1126 }
1127
1128 // Handle last instruction.
1129 if (!_got_error) {
1130 assert(itr.next_bci() == lim_bci, "must point to end");
1131 if (_has_exceptions || _monitor_top != 0) {
1132 do_exception_edge(&itr);
1133 }
1134 interp1(&itr);
1135
1136 bool fall_through = jump_targets_do(&itr, GenerateOopMap::merge_state, NULL);
1137 if (_got_error) return;
1138
1139 if (itr.code() == Bytecodes::_ret) {
1140 assert(!fall_through, "cannot be set if ret instruction");
1141 // Automatically handles 'wide' ret indicies
1142 ret_jump_targets_do(&itr, GenerateOopMap::merge_state, itr.get_index(), NULL);
1143 } else if (fall_through) {
1144 // Hit end of BB, but the instr. was a fall-through instruction,
1145 // so perform transition as if the BB ended in a "jump".
1146 if (lim_bci != bb[1]._bci) {
1147 verify_error("bytecodes fell through last instruction");
1148 return;
1149 }
1150 merge_state_into_bb(bb + 1);
1151 }
1152 }
1153 }
1154
1155 void GenerateOopMap::do_exception_edge(BytecodeStream* itr) {
1156 // Only check exception edge, if bytecode can trap
1157 if (!Bytecodes::can_trap(itr->code())) return;
1158 switch (itr->code()) {
1159 case Bytecodes::_aload_0:
1160 // These bytecodes can trap for rewriting. We need to assume that
1161 // they do not throw exceptions to make the monitor analysis work.
1162 return;
1163
1164 case Bytecodes::_ireturn:
1165 case Bytecodes::_lreturn:
1166 case Bytecodes::_freturn:
1167 case Bytecodes::_dreturn:
1168 case Bytecodes::_areturn:
1169 case Bytecodes::_return:
1170 // If the monitor stack height is not zero when we leave the method,
1171 // then we are either exiting with a non-empty stack or we have
1172 // found monitor trouble earlier in our analysis. In either case,
1173 // assume an exception could be taken here.
1174 if (_monitor_top == 0) {
1175 return;
1176 }
1177 break;
1178
1179 case Bytecodes::_monitorexit:
1180 // If the monitor stack height is bad_monitors, then we have detected a
1181 // monitor matching problem earlier in the analysis. If the
1182 // monitor stack height is 0, we are about to pop a monitor
1183 // off of an empty stack. In either case, the bytecode
1184 // could throw an exception.
1185 if (_monitor_top != bad_monitors && _monitor_top != 0) {
1186 return;
1187 }
1188 break;
1189 }
1190
1191 if (_has_exceptions) {
1192 int bci = itr->bci();
1193 ExceptionTable exct(method());
1194 for(int i = 0; i< exct.length(); i++) {
1195 int start_pc = exct.start_pc(i);
1196 int end_pc = exct.end_pc(i);
1197 int handler_pc = exct.handler_pc(i);
1198 int catch_type = exct.catch_type_index(i);
1199
1200 if (start_pc <= bci && bci < end_pc) {
1201 BasicBlock *excBB = get_basic_block_at(handler_pc);
1202 guarantee(excBB != NULL, "no basic block for exception");
1203 CellTypeState *excStk = excBB->stack();
1204 CellTypeState *cOpStck = stack();
1205 CellTypeState cOpStck_0 = cOpStck[0];
1206 int cOpStackTop = _stack_top;
1207
1208 // Exception stacks are always the same.
1209 assert(method()->max_stack() > 0, "sanity check");
1210
1211 // We remembered the size and first element of "cOpStck"
1212 // above; now we temporarily set them to the appropriate
1213 // values for an exception handler. */
1214 cOpStck[0] = CellTypeState::make_slot_ref(_max_locals);
1215 _stack_top = 1;
1216
1217 merge_state_into_bb(excBB);
1218
1219 // Now undo the temporary change.
1220 cOpStck[0] = cOpStck_0;
1221 _stack_top = cOpStackTop;
1222
1223 // If this is a "catch all" handler, then we do not need to
1224 // consider any additional handlers.
1225 if (catch_type == 0) {
1226 return;
1227 }
1228 }
1229 }
1230 }
1231
1232 // It is possible that none of the exception handlers would have caught
1233 // the exception. In this case, we will exit the method. We must
1234 // ensure that the monitor stack is empty in this case.
1235 if (_monitor_top == 0) {
1236 return;
1237 }
1238
1239 // We pessimistically assume that this exception can escape the
1240 // method. (It is possible that it will always be caught, but
1241 // we don't care to analyse the types of the catch clauses.)
1242
1243 // We don't set _monitor_top to bad_monitors because there are no successors
1244 // to this exceptional exit.
1245
1246 if (log_is_enabled(Info, monitormismatch) && _monitor_safe) {
1247 // We check _monitor_safe so that we only report the first mismatched
1248 // exceptional exit.
1249 report_monitor_mismatch("non-empty monitor stack at exceptional exit");
1250 }
1251 _monitor_safe = false;
1252
1253 }
1254
1255 void GenerateOopMap::report_monitor_mismatch(const char *msg) {
1256 ResourceMark rm;
1257 outputStream* out = Log(monitormismatch)::info_stream();
1258 out->print("Monitor mismatch in method ");
1259 method()->print_short_name(out);
1260 out->print_cr(": %s", msg);
1261 }
1262
1263 void GenerateOopMap::print_states(outputStream *os,
1264 CellTypeState* vec, int num) {
1265 for (int i = 0; i < num; i++) {
1266 vec[i].print(tty);
1267 }
1268 }
1269
1270 // Print the state values at the current bytecode.
1271 void GenerateOopMap::print_current_state(outputStream *os,
1272 BytecodeStream *currentBC,
1273 bool detailed) {
1274
1275 if (detailed) {
1276 os->print(" %4d vars = ", currentBC->bci());
1277 print_states(os, vars(), _max_locals);
1278 os->print(" %s", Bytecodes::name(currentBC->code()));
1279 switch(currentBC->code()) {
1280 case Bytecodes::_invokevirtual:
1281 case Bytecodes::_invokespecial:
1282 case Bytecodes::_invokestatic:
1283 case Bytecodes::_invokedynamic:
1284 case Bytecodes::_invokeinterface:
1285 int idx = currentBC->has_index_u4() ? currentBC->get_index_u4() : currentBC->get_index_u2_cpcache();
1286 ConstantPool* cp = method()->constants();
1287 int nameAndTypeIdx = cp->name_and_type_ref_index_at(idx);
1288 int signatureIdx = cp->signature_ref_index_at(nameAndTypeIdx);
1289 Symbol* signature = cp->symbol_at(signatureIdx);
1290 os->print("%s", signature->as_C_string());
1291 }
1292 os->cr();
1293 os->print(" stack = ");
1294 print_states(os, stack(), _stack_top);
1295 os->cr();
1296 if (_monitor_top != bad_monitors) {
1297 os->print(" monitors = ");
1298 print_states(os, monitors(), _monitor_top);
1299 } else {
1300 os->print(" [bad monitor stack]");
1301 }
1302 os->cr();
1303 } else {
1304 os->print(" %4d vars = '%s' ", currentBC->bci(), state_vec_to_string(vars(), _max_locals));
1305 os->print(" stack = '%s' ", state_vec_to_string(stack(), _stack_top));
1306 if (_monitor_top != bad_monitors) {
1307 os->print(" monitors = '%s' \t%s", state_vec_to_string(monitors(), _monitor_top), Bytecodes::name(currentBC->code()));
1308 } else {
1309 os->print(" [bad monitor stack]");
1310 }
1311 switch(currentBC->code()) {
1312 case Bytecodes::_invokevirtual:
1313 case Bytecodes::_invokespecial:
1314 case Bytecodes::_invokestatic:
1315 case Bytecodes::_invokedynamic:
1316 case Bytecodes::_invokeinterface:
1317 int idx = currentBC->has_index_u4() ? currentBC->get_index_u4() : currentBC->get_index_u2_cpcache();
1318 ConstantPool* cp = method()->constants();
1319 int nameAndTypeIdx = cp->name_and_type_ref_index_at(idx);
1320 int signatureIdx = cp->signature_ref_index_at(nameAndTypeIdx);
1321 Symbol* signature = cp->symbol_at(signatureIdx);
1322 os->print("%s", signature->as_C_string());
1323 }
1324 os->cr();
1325 }
1326 }
1327
1328 // Sets the current state to be the state after executing the
1329 // current instruction, starting in the current state.
1330 void GenerateOopMap::interp1(BytecodeStream *itr) {
1331 if (TraceNewOopMapGeneration) {
1332 print_current_state(tty, itr, TraceNewOopMapGenerationDetailed);
1333 }
1334
1335 // Should we report the results? Result is reported *before* the instruction at the current bci is executed.
1336 // However, not for calls. For calls we do not want to include the arguments, so we postpone the reporting until
1337 // they have been popped (in method ppl).
1338 if (_report_result == true) {
1339 switch(itr->code()) {
1340 case Bytecodes::_invokevirtual:
1341 case Bytecodes::_invokespecial:
1342 case Bytecodes::_invokestatic:
1343 case Bytecodes::_invokedynamic:
1344 case Bytecodes::_invokeinterface:
1345 _itr_send = itr;
1346 _report_result_for_send = true;
1347 break;
1348 default:
1349 fill_stackmap_for_opcodes(itr, vars(), stack(), _stack_top);
1350 break;
1351 }
1352 }
1353
1354 // abstract interpretation of current opcode
1355 switch(itr->code()) {
1356 case Bytecodes::_nop: break;
1357 case Bytecodes::_goto: break;
1358 case Bytecodes::_goto_w: break;
1359 case Bytecodes::_iinc: break;
1360 case Bytecodes::_return: do_return_monitor_check();
1361 break;
1362
1363 case Bytecodes::_aconst_null:
1364 case Bytecodes::_new: ppush1(CellTypeState::make_line_ref(itr->bci()));
1365 break;
1366
1367 case Bytecodes::_iconst_m1:
1368 case Bytecodes::_iconst_0:
1369 case Bytecodes::_iconst_1:
1370 case Bytecodes::_iconst_2:
1371 case Bytecodes::_iconst_3:
1372 case Bytecodes::_iconst_4:
1373 case Bytecodes::_iconst_5:
1374 case Bytecodes::_fconst_0:
1375 case Bytecodes::_fconst_1:
1376 case Bytecodes::_fconst_2:
1377 case Bytecodes::_bipush:
1378 case Bytecodes::_sipush: ppush1(valCTS); break;
1379
1380 case Bytecodes::_lconst_0:
1381 case Bytecodes::_lconst_1:
1382 case Bytecodes::_dconst_0:
1383 case Bytecodes::_dconst_1: ppush(vvCTS); break;
1384
1385 case Bytecodes::_ldc2_w: ppush(vvCTS); break;
1386
1387 case Bytecodes::_ldc: // fall through:
1388 case Bytecodes::_ldc_w: do_ldc(itr->bci()); break;
1389
1390 case Bytecodes::_iload:
1391 case Bytecodes::_fload: ppload(vCTS, itr->get_index()); break;
1392
1393 case Bytecodes::_lload:
1394 case Bytecodes::_dload: ppload(vvCTS,itr->get_index()); break;
1395
1396 case Bytecodes::_aload: ppload(rCTS, itr->get_index()); break;
1397
1398 case Bytecodes::_iload_0:
1399 case Bytecodes::_fload_0: ppload(vCTS, 0); break;
1400 case Bytecodes::_iload_1:
1401 case Bytecodes::_fload_1: ppload(vCTS, 1); break;
1402 case Bytecodes::_iload_2:
1403 case Bytecodes::_fload_2: ppload(vCTS, 2); break;
1404 case Bytecodes::_iload_3:
1405 case Bytecodes::_fload_3: ppload(vCTS, 3); break;
1406
1407 case Bytecodes::_lload_0:
1408 case Bytecodes::_dload_0: ppload(vvCTS, 0); break;
1409 case Bytecodes::_lload_1:
1410 case Bytecodes::_dload_1: ppload(vvCTS, 1); break;
1411 case Bytecodes::_lload_2:
1412 case Bytecodes::_dload_2: ppload(vvCTS, 2); break;
1413 case Bytecodes::_lload_3:
1414 case Bytecodes::_dload_3: ppload(vvCTS, 3); break;
1415
1416 case Bytecodes::_aload_0: ppload(rCTS, 0); break;
1417 case Bytecodes::_aload_1: ppload(rCTS, 1); break;
1418 case Bytecodes::_aload_2: ppload(rCTS, 2); break;
1419 case Bytecodes::_aload_3: ppload(rCTS, 3); break;
1420
1421 case Bytecodes::_iaload:
1422 case Bytecodes::_faload:
1423 case Bytecodes::_baload:
1424 case Bytecodes::_caload:
1425 case Bytecodes::_saload: pp(vrCTS, vCTS); break;
1426
1427 case Bytecodes::_laload: pp(vrCTS, vvCTS); break;
1428 case Bytecodes::_daload: pp(vrCTS, vvCTS); break;
1429
1430 case Bytecodes::_aaload: pp_new_ref(vrCTS, itr->bci()); break;
1431
1432 case Bytecodes::_istore:
1433 case Bytecodes::_fstore: ppstore(vCTS, itr->get_index()); break;
1434
1435 case Bytecodes::_lstore:
1436 case Bytecodes::_dstore: ppstore(vvCTS, itr->get_index()); break;
1437
1438 case Bytecodes::_astore: do_astore(itr->get_index()); break;
1439
1440 case Bytecodes::_istore_0:
1441 case Bytecodes::_fstore_0: ppstore(vCTS, 0); break;
1442 case Bytecodes::_istore_1:
1443 case Bytecodes::_fstore_1: ppstore(vCTS, 1); break;
1444 case Bytecodes::_istore_2:
1445 case Bytecodes::_fstore_2: ppstore(vCTS, 2); break;
1446 case Bytecodes::_istore_3:
1447 case Bytecodes::_fstore_3: ppstore(vCTS, 3); break;
1448
1449 case Bytecodes::_lstore_0:
1450 case Bytecodes::_dstore_0: ppstore(vvCTS, 0); break;
1451 case Bytecodes::_lstore_1:
1452 case Bytecodes::_dstore_1: ppstore(vvCTS, 1); break;
1453 case Bytecodes::_lstore_2:
1454 case Bytecodes::_dstore_2: ppstore(vvCTS, 2); break;
1455 case Bytecodes::_lstore_3:
1456 case Bytecodes::_dstore_3: ppstore(vvCTS, 3); break;
1457
1458 case Bytecodes::_astore_0: do_astore(0); break;
1459 case Bytecodes::_astore_1: do_astore(1); break;
1460 case Bytecodes::_astore_2: do_astore(2); break;
1461 case Bytecodes::_astore_3: do_astore(3); break;
1462
1463 case Bytecodes::_iastore:
1464 case Bytecodes::_fastore:
1465 case Bytecodes::_bastore:
1466 case Bytecodes::_castore:
1467 case Bytecodes::_sastore: ppop(vvrCTS); break;
1468 case Bytecodes::_lastore:
1469 case Bytecodes::_dastore: ppop(vvvrCTS); break;
1470 case Bytecodes::_aastore: ppop(rvrCTS); break;
1471
1472 case Bytecodes::_pop: ppop_any(1); break;
1473 case Bytecodes::_pop2: ppop_any(2); break;
1474
1475 case Bytecodes::_dup: ppdupswap(1, "11"); break;
1476 case Bytecodes::_dup_x1: ppdupswap(2, "121"); break;
1477 case Bytecodes::_dup_x2: ppdupswap(3, "1321"); break;
1478 case Bytecodes::_dup2: ppdupswap(2, "2121"); break;
1479 case Bytecodes::_dup2_x1: ppdupswap(3, "21321"); break;
1480 case Bytecodes::_dup2_x2: ppdupswap(4, "214321"); break;
1481 case Bytecodes::_swap: ppdupswap(2, "12"); break;
1482
1483 case Bytecodes::_iadd:
1484 case Bytecodes::_fadd:
1485 case Bytecodes::_isub:
1486 case Bytecodes::_fsub:
1487 case Bytecodes::_imul:
1488 case Bytecodes::_fmul:
1489 case Bytecodes::_idiv:
1490 case Bytecodes::_fdiv:
1491 case Bytecodes::_irem:
1492 case Bytecodes::_frem:
1493 case Bytecodes::_ishl:
1494 case Bytecodes::_ishr:
1495 case Bytecodes::_iushr:
1496 case Bytecodes::_iand:
1497 case Bytecodes::_ior:
1498 case Bytecodes::_ixor:
1499 case Bytecodes::_l2f:
1500 case Bytecodes::_l2i:
1501 case Bytecodes::_d2f:
1502 case Bytecodes::_d2i:
1503 case Bytecodes::_fcmpl:
1504 case Bytecodes::_fcmpg: pp(vvCTS, vCTS); break;
1505
1506 case Bytecodes::_ladd:
1507 case Bytecodes::_dadd:
1508 case Bytecodes::_lsub:
1509 case Bytecodes::_dsub:
1510 case Bytecodes::_lmul:
1511 case Bytecodes::_dmul:
1512 case Bytecodes::_ldiv:
1513 case Bytecodes::_ddiv:
1514 case Bytecodes::_lrem:
1515 case Bytecodes::_drem:
1516 case Bytecodes::_land:
1517 case Bytecodes::_lor:
1518 case Bytecodes::_lxor: pp(vvvvCTS, vvCTS); break;
1519
1520 case Bytecodes::_ineg:
1521 case Bytecodes::_fneg:
1522 case Bytecodes::_i2f:
1523 case Bytecodes::_f2i:
1524 case Bytecodes::_i2c:
1525 case Bytecodes::_i2s:
1526 case Bytecodes::_i2b: pp(vCTS, vCTS); break;
1527
1528 case Bytecodes::_lneg:
1529 case Bytecodes::_dneg:
1530 case Bytecodes::_l2d:
1531 case Bytecodes::_d2l: pp(vvCTS, vvCTS); break;
1532
1533 case Bytecodes::_lshl:
1534 case Bytecodes::_lshr:
1535 case Bytecodes::_lushr: pp(vvvCTS, vvCTS); break;
1536
1537 case Bytecodes::_i2l:
1538 case Bytecodes::_i2d:
1539 case Bytecodes::_f2l:
1540 case Bytecodes::_f2d: pp(vCTS, vvCTS); break;
1541
1542 case Bytecodes::_lcmp: pp(vvvvCTS, vCTS); break;
1543 case Bytecodes::_dcmpl:
1544 case Bytecodes::_dcmpg: pp(vvvvCTS, vCTS); break;
1545
1546 case Bytecodes::_ifeq:
1547 case Bytecodes::_ifne:
1548 case Bytecodes::_iflt:
1549 case Bytecodes::_ifge:
1550 case Bytecodes::_ifgt:
1551 case Bytecodes::_ifle:
1552 case Bytecodes::_tableswitch: ppop1(valCTS);
1553 break;
1554 case Bytecodes::_ireturn:
1555 case Bytecodes::_freturn: do_return_monitor_check();
1556 ppop1(valCTS);
1557 break;
1558 case Bytecodes::_if_icmpeq:
1559 case Bytecodes::_if_icmpne:
1560 case Bytecodes::_if_icmplt:
1561 case Bytecodes::_if_icmpge:
1562 case Bytecodes::_if_icmpgt:
1563 case Bytecodes::_if_icmple: ppop(vvCTS);
1564 break;
1565
1566 case Bytecodes::_lreturn: do_return_monitor_check();
1567 ppop(vvCTS);
1568 break;
1569
1570 case Bytecodes::_dreturn: do_return_monitor_check();
1571 ppop(vvCTS);
1572 break;
1573
1574 case Bytecodes::_if_acmpeq:
1575 case Bytecodes::_if_acmpne: ppop(rrCTS); break;
1576
1577 case Bytecodes::_jsr: do_jsr(itr->dest()); break;
1578 case Bytecodes::_jsr_w: do_jsr(itr->dest_w()); break;
1579
1580 case Bytecodes::_getstatic: do_field(true, true, itr->get_index_u2_cpcache(), itr->bci()); break;
1581 case Bytecodes::_putstatic: do_field(false, true, itr->get_index_u2_cpcache(), itr->bci()); break;
1582 case Bytecodes::_getfield: do_field(true, false, itr->get_index_u2_cpcache(), itr->bci()); break;
1583 case Bytecodes::_putfield: do_field(false, false, itr->get_index_u2_cpcache(), itr->bci()); break;
1584
1585 case Bytecodes::_invokevirtual:
1586 case Bytecodes::_invokespecial: do_method(false, false, itr->get_index_u2_cpcache(), itr->bci()); break;
1587 case Bytecodes::_invokestatic: do_method(true, false, itr->get_index_u2_cpcache(), itr->bci()); break;
1588 case Bytecodes::_invokedynamic: do_method(true, false, itr->get_index_u4(), itr->bci()); break;
1589 case Bytecodes::_invokeinterface: do_method(false, true, itr->get_index_u2_cpcache(), itr->bci()); break;
1590 case Bytecodes::_newarray:
1591 case Bytecodes::_anewarray: pp_new_ref(vCTS, itr->bci()); break;
1592 case Bytecodes::_checkcast: do_checkcast(); break;
1593 case Bytecodes::_arraylength:
1594 case Bytecodes::_instanceof: pp(rCTS, vCTS); break;
1595 case Bytecodes::_monitorenter: do_monitorenter(itr->bci()); break;
1596 case Bytecodes::_monitorexit: do_monitorexit(itr->bci()); break;
1597
1598 case Bytecodes::_athrow: // handled by do_exception_edge() BUT ...
1599 // vlh(apple): do_exception_edge() does not get
1600 // called if method has no exception handlers
1601 if ((!_has_exceptions) && (_monitor_top > 0)) {
1602 _monitor_safe = false;
1603 }
1604 break;
1605
1606 case Bytecodes::_areturn: do_return_monitor_check();
1607 ppop1(refCTS);
1608 break;
1609 case Bytecodes::_ifnull:
1610 case Bytecodes::_ifnonnull: ppop1(refCTS); break;
1611 case Bytecodes::_multianewarray: do_multianewarray(*(itr->bcp()+3), itr->bci()); break;
1612
1613 case Bytecodes::_wide: fatal("Iterator should skip this bytecode"); break;
1614 case Bytecodes::_ret: break;
1615
1616 // Java opcodes
1617 case Bytecodes::_lookupswitch: ppop1(valCTS); break;
1618
1619 default:
1620 tty->print("unexpected opcode: %d\n", itr->code());
1621 ShouldNotReachHere();
1622 break;
1623 }
1624 }
1625
1626 void GenerateOopMap::check_type(CellTypeState expected, CellTypeState actual) {
1627 if (!expected.equal_kind(actual)) {
1628 verify_error("wrong type on stack (found: %c expected: %c)", actual.to_char(), expected.to_char());
1629 }
1630 }
1631
1632 void GenerateOopMap::ppstore(CellTypeState *in, int loc_no) {
1633 while(!(*in).is_bottom()) {
1634 CellTypeState expected =*in++;
1635 CellTypeState actual = pop();
1636 check_type(expected, actual);
1637 assert(loc_no >= 0, "sanity check");
1638 set_var(loc_no++, actual);
1639 }
1640 }
1641
1642 void GenerateOopMap::ppload(CellTypeState *out, int loc_no) {
1643 while(!(*out).is_bottom()) {
1644 CellTypeState out1 = *out++;
1645 CellTypeState vcts = get_var(loc_no);
1646 assert(out1.can_be_reference() || out1.can_be_value(),
1647 "can only load refs. and values.");
1648 if (out1.is_reference()) {
1649 assert(loc_no>=0, "sanity check");
1650 if (!vcts.is_reference()) {
1651 // We were asked to push a reference, but the type of the
1652 // variable can be something else
1653 _conflict = true;
1654 if (vcts.can_be_uninit()) {
1655 // It is a ref-uninit conflict (at least). If there are other
1656 // problems, we'll get them in the next round
1657 add_to_ref_init_set(loc_no);
1658 vcts = out1;
1659 } else {
1660 // It wasn't a ref-uninit conflict. So must be a
1661 // ref-val or ref-pc conflict. Split the variable.
1662 record_refval_conflict(loc_no);
1663 vcts = out1;
1664 }
1665 push(out1); // recover...
1666 } else {
1667 push(vcts); // preserve reference.
1668 }
1669 // Otherwise it is a conflict, but one that verification would
1670 // have caught if illegal. In particular, it can't be a topCTS
1671 // resulting from mergeing two difference pcCTS's since the verifier
1672 // would have rejected any use of such a merge.
1673 } else {
1674 push(out1); // handle val/init conflict
1675 }
1676 loc_no++;
1677 }
1678 }
1679
1680 void GenerateOopMap::ppdupswap(int poplen, const char *out) {
1681 CellTypeState actual[5];
1682 assert(poplen < 5, "this must be less than length of actual vector");
1683
1684 // Pop all arguments.
1685 for (int i = 0; i < poplen; i++) {
1686 actual[i] = pop();
1687 }
1688 // Field _state is uninitialized when calling push.
1689 for (int i = poplen; i < 5; i++) {
1690 actual[i] = CellTypeState::uninit;
1691 }
1692
1693 // put them back
1694 char push_ch = *out++;
1695 while (push_ch != '\0') {
1696 int idx = push_ch - '1';
1697 assert(idx >= 0 && idx < poplen, "wrong arguments");
1698 push(actual[idx]);
1699 push_ch = *out++;
1700 }
1701 }
1702
1703 void GenerateOopMap::ppop1(CellTypeState out) {
1704 CellTypeState actual = pop();
1705 check_type(out, actual);
1706 }
1707
1708 void GenerateOopMap::ppop(CellTypeState *out) {
1709 while (!(*out).is_bottom()) {
1710 ppop1(*out++);
1711 }
1712 }
1713
1714 void GenerateOopMap::ppush1(CellTypeState in) {
1715 assert(in.is_reference() | in.is_value(), "sanity check");
1716 push(in);
1717 }
1718
1719 void GenerateOopMap::ppush(CellTypeState *in) {
1720 while (!(*in).is_bottom()) {
1721 ppush1(*in++);
1722 }
1723 }
1724
1725 void GenerateOopMap::pp(CellTypeState *in, CellTypeState *out) {
1726 ppop(in);
1727 ppush(out);
1728 }
1729
1730 void GenerateOopMap::pp_new_ref(CellTypeState *in, int bci) {
1731 ppop(in);
1732 ppush1(CellTypeState::make_line_ref(bci));
1733 }
1734
1735 void GenerateOopMap::ppop_any(int poplen) {
1736 if (_stack_top >= poplen) {
1737 _stack_top -= poplen;
1738 } else {
1739 verify_error("stack underflow");
1740 }
1741 }
1742
1743 // Replace all occurences of the state 'match' with the state 'replace'
1744 // in our current state vector.
1745 void GenerateOopMap::replace_all_CTS_matches(CellTypeState match,
1746 CellTypeState replace) {
1747 int i;
1748 int len = _max_locals + _stack_top;
1749 bool change = false;
1750
1751 for (i = len - 1; i >= 0; i--) {
1752 if (match.equal(_state[i])) {
1753 _state[i] = replace;
1754 }
1755 }
1756
1757 if (_monitor_top > 0) {
1758 int base = _max_locals + _max_stack;
1759 len = base + _monitor_top;
1760 for (i = len - 1; i >= base; i--) {
1761 if (match.equal(_state[i])) {
1762 _state[i] = replace;
1763 }
1764 }
1765 }
1766 }
1767
1768 void GenerateOopMap::do_checkcast() {
1769 CellTypeState actual = pop();
1770 check_type(refCTS, actual);
1771 push(actual);
1772 }
1773
1774 void GenerateOopMap::do_monitorenter(int bci) {
1775 CellTypeState actual = pop();
1776 if (_monitor_top == bad_monitors) {
1777 return;
1778 }
1779
1780 // Bail out when we get repeated locks on an identical monitor. This case
1781 // isn't too hard to handle and can be made to work if supporting nested
1782 // redundant synchronized statements becomes a priority.
1783 //
1784 // See also "Note" in do_monitorexit(), below.
1785 if (actual.is_lock_reference()) {
1786 _monitor_top = bad_monitors;
1787 _monitor_safe = false;
1788
1789 if (log_is_enabled(Info, monitormismatch)) {
1790 report_monitor_mismatch("nested redundant lock -- bailout...");
1791 }
1792 return;
1793 }
1794
1795 CellTypeState lock = CellTypeState::make_lock_ref(bci);
1796 check_type(refCTS, actual);
1797 if (!actual.is_info_top()) {
1798 replace_all_CTS_matches(actual, lock);
1799 monitor_push(lock);
1800 }
1801 }
1802
1803 void GenerateOopMap::do_monitorexit(int bci) {
1804 CellTypeState actual = pop();
1805 if (_monitor_top == bad_monitors) {
1806 return;
1807 }
1808 check_type(refCTS, actual);
1809 CellTypeState expected = monitor_pop();
1810 if (!actual.is_lock_reference() || !expected.equal(actual)) {
1811 // The monitor we are exiting is not verifiably the one
1812 // on the top of our monitor stack. This causes a monitor
1813 // mismatch.
1814 _monitor_top = bad_monitors;
1815 _monitor_safe = false;
1816
1817 // We need to mark this basic block as changed so that
1818 // this monitorexit will be visited again. We need to
1819 // do this to ensure that we have accounted for the
1820 // possibility that this bytecode will throw an
1821 // exception.
1822 BasicBlock* bb = get_basic_block_containing(bci);
1823 guarantee(bb != NULL, "no basic block for bci");
1824 bb->set_changed(true);
1825 bb->_monitor_top = bad_monitors;
1826
1827 if (log_is_enabled(Info, monitormismatch)) {
1828 report_monitor_mismatch("improper monitor pair");
1829 }
1830 } else {
1831 // This code is a fix for the case where we have repeated
1832 // locking of the same object in straightline code. We clear
1833 // out the lock when it is popped from the monitor stack
1834 // and replace it with an unobtrusive reference value that can
1835 // be locked again.
1836 //
1837 // Note: when generateOopMap is fixed to properly handle repeated,
1838 // nested, redundant locks on the same object, then this
1839 // fix will need to be removed at that time.
1840 replace_all_CTS_matches(actual, CellTypeState::make_line_ref(bci));
1841 }
1842 }
1843
1844 void GenerateOopMap::do_return_monitor_check() {
1845 if (_monitor_top > 0) {
1846 // The monitor stack must be empty when we leave the method
1847 // for the monitors to be properly matched.
1848 _monitor_safe = false;
1849
1850 // Since there are no successors to the *return bytecode, it
1851 // isn't necessary to set _monitor_top to bad_monitors.
1852
1853 if (log_is_enabled(Info, monitormismatch)) {
1854 report_monitor_mismatch("non-empty monitor stack at return");
1855 }
1856 }
1857 }
1858
1859 void GenerateOopMap::do_jsr(int targ_bci) {
1860 push(CellTypeState::make_addr(targ_bci));
1861 }
1862
1863
1864
1865 void GenerateOopMap::do_ldc(int bci) {
1866 Bytecode_loadconstant ldc(method(), bci);
1867 ConstantPool* cp = method()->constants();
1868 constantTag tag = cp->tag_at(ldc.pool_index()); // idx is index in resolved_references
1869 BasicType bt = ldc.result_type();
1870 CellTypeState cts;
1871 if (tag.basic_type() == T_OBJECT) {
1872 assert(!tag.is_string_index() && !tag.is_klass_index(), "Unexpected index tag");
1873 assert(bt == T_OBJECT, "Guard is incorrect");
1874 cts = CellTypeState::make_line_ref(bci);
1875 } else {
1876 assert(bt != T_OBJECT, "Guard is incorrect");
1877 cts = valCTS;
1878 }
1879 ppush1(cts);
1880 }
1881
1882 void GenerateOopMap::do_multianewarray(int dims, int bci) {
1883 assert(dims >= 1, "sanity check");
1884 for(int i = dims -1; i >=0; i--) {
1885 ppop1(valCTS);
1886 }
1887 ppush1(CellTypeState::make_line_ref(bci));
1888 }
1889
1890 void GenerateOopMap::do_astore(int idx) {
1891 CellTypeState r_or_p = pop();
1892 if (!r_or_p.is_address() && !r_or_p.is_reference()) {
1893 // We actually expected ref or pc, but we only report that we expected a ref. It does not
1894 // really matter (at least for now)
1895 verify_error("wrong type on stack (found: %c, expected: {pr})", r_or_p.to_char());
1896 return;
1897 }
1898 set_var(idx, r_or_p);
1899 }
1900
1901 // Copies bottom/zero terminated CTS string from "src" into "dst".
1902 // Does NOT terminate with a bottom. Returns the number of cells copied.
1903 int GenerateOopMap::copy_cts(CellTypeState *dst, CellTypeState *src) {
1904 int idx = 0;
1905 while (!src[idx].is_bottom()) {
1906 dst[idx] = src[idx];
1907 idx++;
1908 }
1909 return idx;
1910 }
1911
1912 void GenerateOopMap::do_field(int is_get, int is_static, int idx, int bci) {
1913 // Dig up signature for field in constant pool
1914 ConstantPool* cp = method()->constants();
1915 int nameAndTypeIdx = cp->name_and_type_ref_index_at(idx);
1916 int signatureIdx = cp->signature_ref_index_at(nameAndTypeIdx);
1917 Symbol* signature = cp->symbol_at(signatureIdx);
1918
1919 // Parse signature (espcially simple for fields)
1920 assert(signature->utf8_length() > 0, "field signatures cannot have zero length");
1921 // The signature is UFT8 encoded, but the first char is always ASCII for signatures.
1922 char sigch = (char)*(signature->base());
1923 CellTypeState temp[4];
1924 CellTypeState *eff = sigchar_to_effect(sigch, bci, temp);
1925
1926 CellTypeState in[4];
1927 CellTypeState *out;
1928 int i = 0;
1929
1930 if (is_get) {
1931 out = eff;
1932 } else {
1933 out = epsilonCTS;
1934 i = copy_cts(in, eff);
1935 }
1936 if (!is_static) in[i++] = CellTypeState::ref;
1937 in[i] = CellTypeState::bottom;
1938 assert(i<=3, "sanity check");
1939 pp(in, out);
1940 }
1941
1942 void GenerateOopMap::do_method(int is_static, int is_interface, int idx, int bci) {
1943 // Dig up signature for field in constant pool
1944 ConstantPool* cp = _method->constants();
1945 Symbol* signature = cp->signature_ref_at(idx);
1946
1947 // Parse method signature
1948 CellTypeState out[4];
1949 CellTypeState in[MAXARGSIZE+1]; // Includes result
1950 ComputeCallStack cse(signature);
1951
1952 // Compute return type
1953 int res_length= cse.compute_for_returntype(out);
1954
1955 // Temporary hack.
1956 if (out[0].equal(CellTypeState::ref) && out[1].equal(CellTypeState::bottom)) {
1957 out[0] = CellTypeState::make_line_ref(bci);
1958 }
1959
1960 assert(res_length<=4, "max value should be vv");
1961
1962 // Compute arguments
1963 int arg_length = cse.compute_for_parameters(is_static != 0, in);
1964 assert(arg_length<=MAXARGSIZE, "too many locals");
1965
1966 // Pop arguments
1967 for (int i = arg_length - 1; i >= 0; i--) ppop1(in[i]);// Do args in reverse order.
1968
1969 // Report results
1970 if (_report_result_for_send == true) {
1971 fill_stackmap_for_opcodes(_itr_send, vars(), stack(), _stack_top);
1972 _report_result_for_send = false;
1973 }
1974
1975 // Push return address
1976 ppush(out);
1977 }
1978
1979 // This is used to parse the signature for fields, since they are very simple...
1980 CellTypeState *GenerateOopMap::sigchar_to_effect(char sigch, int bci, CellTypeState *out) {
1981 // Object and array
1982 if (sigch=='L' || sigch=='[') {
1983 out[0] = CellTypeState::make_line_ref(bci);
1984 out[1] = CellTypeState::bottom;
1985 return out;
1986 }
1987 if (sigch == 'J' || sigch == 'D' ) return vvCTS; // Long and Double
1988 if (sigch == 'V' ) return epsilonCTS; // Void
1989 return vCTS; // Otherwise
1990 }
1991
1992 long GenerateOopMap::_total_byte_count = 0;
1993 elapsedTimer GenerateOopMap::_total_oopmap_time;
1994
1995 // This function assumes "bcs" is at a "ret" instruction and that the vars
1996 // state is valid for that instruction. Furthermore, the ret instruction
1997 // must be the last instruction in "bb" (we store information about the
1998 // "ret" in "bb").
1999 void GenerateOopMap::ret_jump_targets_do(BytecodeStream *bcs, jmpFct_t jmpFct, int varNo, int *data) {
2000 CellTypeState ra = vars()[varNo];
2001 if (!ra.is_good_address()) {
2002 verify_error("ret returns from two jsr subroutines?");
2003 return;
2004 }
2005 int target = ra.get_info();
2006
2007 RetTableEntry* rtEnt = _rt.find_jsrs_for_target(target);
2008 int bci = bcs->bci();
2009 for (int i = 0; i < rtEnt->nof_jsrs(); i++) {
2010 int target_bci = rtEnt->jsrs(i);
2011 // Make sure a jrtRet does not set the changed bit for dead basicblock.
2012 BasicBlock* jsr_bb = get_basic_block_containing(target_bci - 1);
2013 debug_only(BasicBlock* target_bb = &jsr_bb[1];)
2014 assert(target_bb == get_basic_block_at(target_bci), "wrong calc. of successor basicblock");
2015 bool alive = jsr_bb->is_alive();
2016 if (TraceNewOopMapGeneration) {
2017 tty->print("pc = %d, ret -> %d alive: %s\n", bci, target_bci, alive ? "true" : "false");
2018 }
2019 if (alive) jmpFct(this, target_bci, data);
2020 }
2021 }
2022
2023 //
2024 // Debug method
2025 //
2026 char* GenerateOopMap::state_vec_to_string(CellTypeState* vec, int len) {
2027 #ifdef ASSERT
2028 int checklen = MAX3(_max_locals, _max_stack, _max_monitors) + 1;
2029 assert(len < checklen, "state_vec_buf overflow");
2030 #endif
2031 for (int i = 0; i < len; i++) _state_vec_buf[i] = vec[i].to_char();
2032 _state_vec_buf[len] = 0;
2033 return _state_vec_buf;
2034 }
2035
2036 void GenerateOopMap::print_time() {
2037 tty->print_cr ("Accumulated oopmap times:");
2038 tty->print_cr ("---------------------------");
2039 tty->print_cr (" Total : %3.3f sec.", GenerateOopMap::_total_oopmap_time.seconds());
2040 tty->print_cr (" (%3.0f bytecodes per sec) ",
2041 GenerateOopMap::_total_byte_count / GenerateOopMap::_total_oopmap_time.seconds());
2042 }
2043
2044 //
2045 // ============ Main Entry Point ===========
2046 //
2047 GenerateOopMap::GenerateOopMap(const methodHandle& method) {
2048 // We have to initialize all variables here, that can be queried directly
2049 _method = method;
2050 _max_locals=0;
2051 _init_vars = NULL;
2052
2053 #ifndef PRODUCT
2054 // If we are doing a detailed trace, include the regular trace information.
2055 if (TraceNewOopMapGenerationDetailed) {
2056 TraceNewOopMapGeneration = true;
2057 }
2058 #endif
2059 }
2060
2061 void GenerateOopMap::compute_map(TRAPS) {
2062 #ifndef PRODUCT
2063 if (TimeOopMap2) {
2064 method()->print_short_name(tty);
2065 tty->print(" ");
2066 }
2067 if (TimeOopMap) {
2068 _total_byte_count += method()->code_size();
2069 }
2070 #endif
2071 TraceTime t_single("oopmap time", TimeOopMap2);
2072 TraceTime t_all(NULL, &_total_oopmap_time, TimeOopMap);
2073
2074 // Initialize values
2075 _got_error = false;
2076 _conflict = false;
2077 _max_locals = method()->max_locals();
2078 _max_stack = method()->max_stack();
2079 _has_exceptions = (method()->has_exception_handler());
2080 _nof_refval_conflicts = 0;
2081 _init_vars = new GrowableArray<intptr_t>(5); // There are seldom more than 5 init_vars
2082 _report_result = false;
2083 _report_result_for_send = false;
2084 _new_var_map = NULL;
2085 _ret_adr_tos = new GrowableArray<intptr_t>(5); // 5 seems like a good number;
2086 _did_rewriting = false;
2087 _did_relocation = false;
2088
2089 if (TraceNewOopMapGeneration) {
2090 tty->print("Method name: %s\n", method()->name()->as_C_string());
2091 if (Verbose) {
2092 _method->print_codes();
2093 tty->print_cr("Exception table:");
2094 ExceptionTable excps(method());
2095 for(int i = 0; i < excps.length(); i ++) {
2096 tty->print_cr("[%d - %d] -> %d",
2097 excps.start_pc(i), excps.end_pc(i), excps.handler_pc(i));
2098 }
2099 }
2100 }
2101
2102 // if no code - do nothing
2103 // compiler needs info
2104 if (method()->code_size() == 0 || _max_locals + method()->max_stack() == 0) {
2105 fill_stackmap_prolog(0);
2106 fill_stackmap_epilog();
2107 return;
2108 }
2109 // Step 1: Compute all jump targets and their return value
2110 if (!_got_error)
2111 _rt.compute_ret_table(_method);
2112
2113 // Step 2: Find all basic blocks and count GC points
2114 if (!_got_error)
2115 mark_bbheaders_and_count_gc_points();
2116
2117 // Step 3: Calculate stack maps
2118 if (!_got_error)
2119 do_interpretation();
2120
2121 // Step 4:Return results
2122 if (!_got_error && report_results())
2123 report_result();
2124
2125 if (_got_error) {
2126 THROW_HANDLE(_exception);
2127 }
2128 }
2129
2130 // Error handling methods
2131 // These methods create an exception for the current thread which is thrown
2132 // at the bottom of the call stack, when it returns to compute_map(). The
2133 // _got_error flag controls execution. NOT TODO: The VM exception propagation
2134 // mechanism using TRAPS/CHECKs could be used here instead but it would need
2135 // to be added as a parameter to every function and checked for every call.
2136 // The tons of extra code it would generate didn't seem worth the change.
2137 //
2138 void GenerateOopMap::error_work(const char *format, va_list ap) {
2139 _got_error = true;
2140 char msg_buffer[512];
2141 vsnprintf(msg_buffer, sizeof(msg_buffer), format, ap);
2142 // Append method name
2143 char msg_buffer2[512];
2144 jio_snprintf(msg_buffer2, sizeof(msg_buffer2), "%s in method %s", msg_buffer, method()->name()->as_C_string());
2145 _exception = Exceptions::new_exception(Thread::current(),
2146 vmSymbols::java_lang_LinkageError(), msg_buffer2);
2147 }
2148
2149 void GenerateOopMap::report_error(const char *format, ...) {
2150 va_list ap;
2151 va_start(ap, format);
2152 error_work(format, ap);
2153 }
2154
2155 void GenerateOopMap::verify_error(const char *format, ...) {
2156 // We do not distinguish between different types of errors for verification
2157 // errors. Let the verifier give a better message.
2158 const char *msg = "Illegal class file encountered. Try running with -Xverify:all";
2159 _got_error = true;
2160 // Append method name
2161 char msg_buffer2[512];
2162 jio_snprintf(msg_buffer2, sizeof(msg_buffer2), "%s in method %s", msg,
2163 method()->name()->as_C_string());
2164 _exception = Exceptions::new_exception(Thread::current(),
2165 vmSymbols::java_lang_LinkageError(), msg_buffer2);
2166 }
2167
2168 //
2169 // Report result opcodes
2170 //
2171 void GenerateOopMap::report_result() {
2172
2173 if (TraceNewOopMapGeneration) tty->print_cr("Report result pass");
2174
2175 // We now want to report the result of the parse
2176 _report_result = true;
2177
2178 // Prolog code
2179 fill_stackmap_prolog(_gc_points);
2180
2181 // Mark everything changed, then do one interpretation pass.
2182 for (int i = 0; i<_bb_count; i++) {
2183 if (_basic_blocks[i].is_reachable()) {
2184 _basic_blocks[i].set_changed(true);
2185 interp_bb(&_basic_blocks[i]);
2186 }
2187 }
2188
2189 // Note: Since we are skipping dead-code when we are reporting results, then
2190 // the no. of encountered gc-points might be fewer than the previously number
2191 // we have counted. (dead-code is a pain - it should be removed before we get here)
2192 fill_stackmap_epilog();
2193
2194 // Report initvars
2195 fill_init_vars(_init_vars);
2196
2197 _report_result = false;
2198 }
2199
2200 void GenerateOopMap::result_for_basicblock(int bci) {
2201 if (TraceNewOopMapGeneration) tty->print_cr("Report result pass for basicblock");
2202
2203 // We now want to report the result of the parse
2204 _report_result = true;
2205
2206 // Find basicblock and report results
2207 BasicBlock* bb = get_basic_block_containing(bci);
2208 guarantee(bb != NULL, "no basic block for bci");
2209 assert(bb->is_reachable(), "getting result from unreachable basicblock");
2210 bb->set_changed(true);
2211 interp_bb(bb);
2212 }
2213
2214 //
2215 // Conflict handling code
2216 //
2217
2218 void GenerateOopMap::record_refval_conflict(int varNo) {
2219 assert(varNo>=0 && varNo< _max_locals, "index out of range");
2220
2221 if (TraceOopMapRewrites) {
2222 tty->print("### Conflict detected (local no: %d)\n", varNo);
2223 }
2224
2225 if (!_new_var_map) {
2226 _new_var_map = NEW_RESOURCE_ARRAY(int, _max_locals);
2227 for (int k = 0; k < _max_locals; k++) _new_var_map[k] = k;
2228 }
2229
2230 if ( _new_var_map[varNo] == varNo) {
2231 // Check if max. number of locals has been reached
2232 if (_max_locals + _nof_refval_conflicts >= MAX_LOCAL_VARS) {
2233 report_error("Rewriting exceeded local variable limit");
2234 return;
2235 }
2236 _new_var_map[varNo] = _max_locals + _nof_refval_conflicts;
2237 _nof_refval_conflicts++;
2238 }
2239 }
2240
2241 void GenerateOopMap::rewrite_refval_conflicts()
2242 {
2243 // We can get here two ways: Either a rewrite conflict was detected, or
2244 // an uninitialize reference was detected. In the second case, we do not
2245 // do any rewriting, we just want to recompute the reference set with the
2246 // new information
2247
2248 int nof_conflicts = 0; // Used for debugging only
2249
2250 if ( _nof_refval_conflicts == 0 )
2251 return;
2252
2253 // Check if rewrites are allowed in this parse.
2254 if (!allow_rewrites() && !IgnoreRewrites) {
2255 fatal("Rewriting method not allowed at this stage");
2256 }
2257
2258
2259 // This following flag is to tempoary supress rewrites. The locals that might conflict will
2260 // all be set to contain values. This is UNSAFE - however, until the rewriting has been completely
2261 // tested it is nice to have.
2262 if (IgnoreRewrites) {
2263 if (Verbose) {
2264 tty->print("rewrites suppressed for local no. ");
2265 for (int l = 0; l < _max_locals; l++) {
2266 if (_new_var_map[l] != l) {
2267 tty->print("%d ", l);
2268 vars()[l] = CellTypeState::value;
2269 }
2270 }
2271 tty->cr();
2272 }
2273
2274 // That was that...
2275 _new_var_map = NULL;
2276 _nof_refval_conflicts = 0;
2277 _conflict = false;
2278
2279 return;
2280 }
2281
2282 // Tracing flag
2283 _did_rewriting = true;
2284
2285 if (TraceOopMapRewrites) {
2286 tty->print_cr("ref/value conflict for method %s - bytecodes are getting rewritten", method()->name()->as_C_string());
2287 method()->print();
2288 method()->print_codes();
2289 }
2290
2291 assert(_new_var_map!=NULL, "nothing to rewrite");
2292 assert(_conflict==true, "We should not be here");
2293
2294 compute_ret_adr_at_TOS();
2295 if (!_got_error) {
2296 for (int k = 0; k < _max_locals && !_got_error; k++) {
2297 if (_new_var_map[k] != k) {
2298 if (TraceOopMapRewrites) {
2299 tty->print_cr("Rewriting: %d -> %d", k, _new_var_map[k]);
2300 }
2301 rewrite_refval_conflict(k, _new_var_map[k]);
2302 if (_got_error) return;
2303 nof_conflicts++;
2304 }
2305 }
2306 }
2307
2308 assert(nof_conflicts == _nof_refval_conflicts, "sanity check");
2309
2310 // Adjust the number of locals
2311 method()->set_max_locals(_max_locals+_nof_refval_conflicts);
2312 _max_locals += _nof_refval_conflicts;
2313
2314 // That was that...
2315 _new_var_map = NULL;
2316 _nof_refval_conflicts = 0;
2317 }
2318
2319 void GenerateOopMap::rewrite_refval_conflict(int from, int to) {
2320 bool startOver;
2321 do {
2322 // Make sure that the BytecodeStream is constructed in the loop, since
2323 // during rewriting a new method oop is going to be used, and the next time
2324 // around we want to use that.
2325 BytecodeStream bcs(_method);
2326 startOver = false;
2327
2328 while( !startOver && !_got_error &&
2329 // test bcs in case method changed and it became invalid
2330 bcs.next() >=0) {
2331 startOver = rewrite_refval_conflict_inst(&bcs, from, to);
2332 }
2333 } while (startOver && !_got_error);
2334 }
2335
2336 /* If the current instruction is one that uses local variable "from"
2337 in a ref way, change it to use "to". There's a subtle reason why we
2338 renumber the ref uses and not the non-ref uses: non-ref uses may be
2339 2 slots wide (double, long) which would necessitate keeping track of
2340 whether we should add one or two variables to the method. If the change
2341 affected the width of some instruction, returns "TRUE"; otherwise, returns "FALSE".
2342 Another reason for moving ref's value is for solving (addr, ref) conflicts, which
2343 both uses aload/astore methods.
2344 */
2345 bool GenerateOopMap::rewrite_refval_conflict_inst(BytecodeStream *itr, int from, int to) {
2346 Bytecodes::Code bc = itr->code();
2347 int index;
2348 int bci = itr->bci();
2349
2350 if (is_aload(itr, &index) && index == from) {
2351 if (TraceOopMapRewrites) {
2352 tty->print_cr("Rewriting aload at bci: %d", bci);
2353 }
2354 return rewrite_load_or_store(itr, Bytecodes::_aload, Bytecodes::_aload_0, to);
2355 }
2356
2357 if (is_astore(itr, &index) && index == from) {
2358 if (!stack_top_holds_ret_addr(bci)) {
2359 if (TraceOopMapRewrites) {
2360 tty->print_cr("Rewriting astore at bci: %d", bci);
2361 }
2362 return rewrite_load_or_store(itr, Bytecodes::_astore, Bytecodes::_astore_0, to);
2363 } else {
2364 if (TraceOopMapRewrites) {
2365 tty->print_cr("Supress rewriting of astore at bci: %d", bci);
2366 }
2367 }
2368 }
2369
2370 return false;
2371 }
2372
2373 // The argument to this method is:
2374 // bc : Current bytecode
2375 // bcN : either _aload or _astore
2376 // bc0 : either _aload_0 or _astore_0
2377 bool GenerateOopMap::rewrite_load_or_store(BytecodeStream *bcs, Bytecodes::Code bcN, Bytecodes::Code bc0, unsigned int varNo) {
2378 assert(bcN == Bytecodes::_astore || bcN == Bytecodes::_aload, "wrong argument (bcN)");
2379 assert(bc0 == Bytecodes::_astore_0 || bc0 == Bytecodes::_aload_0, "wrong argument (bc0)");
2380 int ilen = Bytecodes::length_at(_method(), bcs->bcp());
2381 int newIlen;
2382
2383 if (ilen == 4) {
2384 // Original instruction was wide; keep it wide for simplicity
2385 newIlen = 4;
2386 } else if (varNo < 4)
2387 newIlen = 1;
2388 else if (varNo >= 256)
2389 newIlen = 4;
2390 else
2391 newIlen = 2;
2392
2393 // If we need to relocate in order to patch the byte, we
2394 // do the patching in a temp. buffer, that is passed to the reloc.
2395 // The patching of the bytecode stream is then done by the Relocator.
2396 // This is neccesary, since relocating the instruction at a certain bci, might
2397 // also relocate that instruction, e.g., if a _goto before it gets widen to a _goto_w.
2398 // Hence, we do not know which bci to patch after relocation.
2399
2400 assert(newIlen <= 4, "sanity check");
2401 u_char inst_buffer[4]; // Max. instruction size is 4.
2402 address bcp;
2403
2404 if (newIlen != ilen) {
2405 // Relocation needed do patching in temp. buffer
2406 bcp = (address)inst_buffer;
2407 } else {
2408 bcp = _method->bcp_from(bcs->bci());
2409 }
2410
2411 // Patch either directly in Method* or in temp. buffer
2412 if (newIlen == 1) {
2413 assert(varNo < 4, "varNo too large");
2414 *bcp = bc0 + varNo;
2415 } else if (newIlen == 2) {
2416 assert(varNo < 256, "2-byte index needed!");
2417 *(bcp + 0) = bcN;
2418 *(bcp + 1) = varNo;
2419 } else {
2420 assert(newIlen == 4, "Wrong instruction length");
2421 *(bcp + 0) = Bytecodes::_wide;
2422 *(bcp + 1) = bcN;
2423 Bytes::put_Java_u2(bcp+2, varNo);
2424 }
2425
2426 if (newIlen != ilen) {
2427 expand_current_instr(bcs->bci(), ilen, newIlen, inst_buffer);
2428 }
2429
2430
2431 return (newIlen != ilen);
2432 }
2433
2434 class RelocCallback : public RelocatorListener {
2435 private:
2436 GenerateOopMap* _gom;
2437 public:
2438 RelocCallback(GenerateOopMap* gom) { _gom = gom; };
2439
2440 // Callback method
2441 virtual void relocated(int bci, int delta, int new_code_length) {
2442 _gom->update_basic_blocks (bci, delta, new_code_length);
2443 _gom->update_ret_adr_at_TOS(bci, delta);
2444 _gom->_rt.update_ret_table (bci, delta);
2445 }
2446 };
2447
2448 // Returns true if expanding was succesful. Otherwise, reports an error and
2449 // returns false.
2450 void GenerateOopMap::expand_current_instr(int bci, int ilen, int newIlen, u_char inst_buffer[]) {
2451 Thread *THREAD = Thread::current(); // Could really have TRAPS argument.
2452 RelocCallback rcb(this);
2453 Relocator rc(_method, &rcb);
2454 methodHandle m= rc.insert_space_at(bci, newIlen, inst_buffer, THREAD);
2455 if (m.is_null() || HAS_PENDING_EXCEPTION) {
2456 report_error("could not rewrite method - exception occurred or bytecode buffer overflow");
2457 return;
2458 }
2459
2460 // Relocator returns a new method oop.
2461 _did_relocation = true;
2462 _method = m;
2463 }
2464
2465
2466 bool GenerateOopMap::is_astore(BytecodeStream *itr, int *index) {
2467 Bytecodes::Code bc = itr->code();
2468 switch(bc) {
2469 case Bytecodes::_astore_0:
2470 case Bytecodes::_astore_1:
2471 case Bytecodes::_astore_2:
2472 case Bytecodes::_astore_3:
2473 *index = bc - Bytecodes::_astore_0;
2474 return true;
2475 case Bytecodes::_astore:
2476 *index = itr->get_index();
2477 return true;
2478 }
2479 return false;
2480 }
2481
2482 bool GenerateOopMap::is_aload(BytecodeStream *itr, int *index) {
2483 Bytecodes::Code bc = itr->code();
2484 switch(bc) {
2485 case Bytecodes::_aload_0:
2486 case Bytecodes::_aload_1:
2487 case Bytecodes::_aload_2:
2488 case Bytecodes::_aload_3:
2489 *index = bc - Bytecodes::_aload_0;
2490 return true;
2491
2492 case Bytecodes::_aload:
2493 *index = itr->get_index();
2494 return true;
2495 }
2496 return false;
2497 }
2498
2499
2500 // Return true iff the top of the operand stack holds a return address at
2501 // the current instruction
2502 bool GenerateOopMap::stack_top_holds_ret_addr(int bci) {
2503 for(int i = 0; i < _ret_adr_tos->length(); i++) {
2504 if (_ret_adr_tos->at(i) == bci)
2505 return true;
2506 }
2507
2508 return false;
2509 }
2510
2511 void GenerateOopMap::compute_ret_adr_at_TOS() {
2512 assert(_ret_adr_tos != NULL, "must be initialized");
2513 _ret_adr_tos->clear();
2514
2515 for (int i = 0; i < bb_count(); i++) {
2516 BasicBlock* bb = &_basic_blocks[i];
2517
2518 // Make sure to only check basicblocks that are reachable
2519 if (bb->is_reachable()) {
2520
2521 // For each Basic block we check all instructions
2522 BytecodeStream bcs(_method);
2523 bcs.set_interval(bb->_bci, next_bb_start_pc(bb));
2524
2525 restore_state(bb);
2526
2527 while (bcs.next()>=0 && !_got_error) {
2528 // TDT: should this be is_good_address() ?
2529 if (_stack_top > 0 && stack()[_stack_top-1].is_address()) {
2530 _ret_adr_tos->append(bcs.bci());
2531 if (TraceNewOopMapGeneration) {
2532 tty->print_cr("Ret_adr TOS at bci: %d", bcs.bci());
2533 }
2534 }
2535 interp1(&bcs);
2536 }
2537 }
2538 }
2539 }
2540
2541 void GenerateOopMap::update_ret_adr_at_TOS(int bci, int delta) {
2542 for(int i = 0; i < _ret_adr_tos->length(); i++) {
2543 int v = _ret_adr_tos->at(i);
2544 if (v > bci) _ret_adr_tos->at_put(i, v + delta);
2545 }
2546 }
2547
2548 // ===================================================================
2549
2550 #ifndef PRODUCT
2551 int ResolveOopMapConflicts::_nof_invocations = 0;
2552 int ResolveOopMapConflicts::_nof_rewrites = 0;
2553 int ResolveOopMapConflicts::_nof_relocations = 0;
2554 #endif
2555
2556 methodHandle ResolveOopMapConflicts::do_potential_rewrite(TRAPS) {
2557 compute_map(CHECK_(methodHandle()));
2558
2559 #ifndef PRODUCT
2560 // Tracking and statistics
2561 if (PrintRewrites) {
2562 _nof_invocations++;
2563 if (did_rewriting()) {
2564 _nof_rewrites++;
2565 if (did_relocation()) _nof_relocations++;
2566 tty->print("Method was rewritten %s: ", (did_relocation()) ? "and relocated" : "");
2567 method()->print_value(); tty->cr();
2568 tty->print_cr("Cand.: %d rewrts: %d (%d%%) reloc.: %d (%d%%)",
2569 _nof_invocations,
2570 _nof_rewrites, (_nof_rewrites * 100) / _nof_invocations,
2571 _nof_relocations, (_nof_relocations * 100) / _nof_invocations);
2572 }
2573 }
2574 #endif
2575 return methodHandle(THREAD, method());
2576 }