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 "prims/methodHandles.hpp"
32 #include "runtime/handles.inline.hpp"
33 #include "runtime/java.hpp"
34 #include "runtime/relocator.hpp"
35 #include "runtime/timerTrace.hpp"
36 #include "utilities/bitMap.inline.hpp"
37 #include "utilities/ostream.hpp"
38
39 //
40 //
41 // Compute stack layouts for each instruction in method.
42 //
43 // Problems:
44 // - What to do about jsr with different types of local vars?
45 // Need maps that are conditional on jsr path?
46 // - Jsr and exceptions should be done more efficiently (the retAddr stuff)
47 //
48 // Alternative:
49 // - Could extend verifier to provide this information.
50 // For: one fewer abstract interpreter to maintain. Against: the verifier
51 // solves a bigger problem so slower (undesirable to force verification of
52 // everything?).
53 //
54 // Algorithm:
55 // Partition bytecodes into basic blocks
56 // For each basic block: store entry state (vars, stack). For instructions
57 // inside basic blocks we do not store any state (instead we recompute it
58 // from state produced by previous instruction).
59 //
60 // Perform abstract interpretation of bytecodes over this lattice:
61 //
62 // _--'#'--_
63 // / / \ \
64 // / / \ \
65 // / | | \
66 // 'r' 'v' 'p' ' '
67 // \ | | /
68 // \ \ / /
69 // \ \ / /
70 // -- '@' --
71 //
72 // '#' top, result of conflict merge
73 // 'r' reference type
74 // 'v' value type
75 // 'p' pc type for jsr/ret
76 // ' ' uninitialized; never occurs on operand stack in Java
77 // '@' bottom/unexecuted; initial state each bytecode.
78 //
79 // Basic block headers are the only merge points. We use this iteration to
80 // compute the information:
81 //
82 // find basic blocks;
83 // initialize them with uninitialized state;
84 // initialize first BB according to method signature;
85 // mark first BB changed
86 // while (some BB is changed) do {
87 // perform abstract interpration of all bytecodes in BB;
88 // merge exit state of BB into entry state of all successor BBs,
89 // noting if any of these change;
90 // }
91 //
92 // One additional complication is necessary. The jsr instruction pushes
93 // a return PC on the stack (a 'p' type in the abstract interpretation).
94 // To be able to process "ret" bytecodes, we keep track of these return
95 // PC's in a 'retAddrs' structure in abstract interpreter context (when
96 // processing a "ret" bytecodes, it is not sufficient to know that it gets
97 // an argument of the right type 'p'; we need to know which address it
98 // returns to).
99 //
100 // (Note this comment is borrowed form the original author of the algorithm)
101
102 // ComputeCallStack
103 //
104 // Specialization of SignatureIterator - compute the effects of a call
105 //
106 class ComputeCallStack : public SignatureIterator {
107 CellTypeState *_effect;
108 int _idx;
109
110 void setup();
111 void set(CellTypeState state) { _effect[_idx++] = state; }
112 int length() { return _idx; };
113
114 virtual void do_bool () { set(CellTypeState::value); };
115 virtual void do_char () { set(CellTypeState::value); };
116 virtual void do_float () { set(CellTypeState::value); };
117 virtual void do_byte () { set(CellTypeState::value); };
118 virtual void do_short () { set(CellTypeState::value); };
119 virtual void do_int () { set(CellTypeState::value); };
120 virtual void do_void () { set(CellTypeState::bottom);};
121 virtual void do_object(int begin, int end) { set(CellTypeState::ref); };
122 virtual void do_array (int begin, int end) { set(CellTypeState::ref); };
123
124 void do_double() { set(CellTypeState::value);
125 set(CellTypeState::value); }
126 void do_long () { set(CellTypeState::value);
127 set(CellTypeState::value); }
128
129 public:
130 ComputeCallStack(Symbol* signature) : SignatureIterator(signature) {};
131
132 // Compute methods
133 int compute_for_parameters(bool is_static, CellTypeState *effect) {
134 _idx = 0;
135 _effect = effect;
136
137 if (!is_static)
138 effect[_idx++] = CellTypeState::ref;
139
140 iterate_parameters();
141
142 return length();
143 };
144
145 int compute_for_returntype(CellTypeState *effect) {
146 _idx = 0;
147 _effect = effect;
148 iterate_returntype();
149 set(CellTypeState::bottom); // Always terminate with a bottom state, so ppush works
150
151 return length();
152 }
153 };
154
155 //=========================================================================================
156 // ComputeEntryStack
157 //
158 // Specialization of SignatureIterator - in order to set up first stack frame
159 //
160 class ComputeEntryStack : public SignatureIterator {
161 CellTypeState *_effect;
162 int _idx;
163
164 void setup();
165 void set(CellTypeState state) { _effect[_idx++] = state; }
166 int length() { return _idx; };
167
168 virtual void do_bool () { set(CellTypeState::value); };
169 virtual void do_char () { set(CellTypeState::value); };
170 virtual void do_float () { set(CellTypeState::value); };
171 virtual void do_byte () { set(CellTypeState::value); };
172 virtual void do_short () { set(CellTypeState::value); };
173 virtual void do_int () { set(CellTypeState::value); };
174 virtual void do_void () { set(CellTypeState::bottom);};
175 virtual void do_object(int begin, int end) { set(CellTypeState::make_slot_ref(_idx)); }
176 virtual void do_array (int begin, int end) { set(CellTypeState::make_slot_ref(_idx)); }
177
178 void do_double() { set(CellTypeState::value);
179 set(CellTypeState::value); }
180 void do_long () { set(CellTypeState::value);
181 set(CellTypeState::value); }
182
183 public:
184 ComputeEntryStack(Symbol* signature) : SignatureIterator(signature) {};
185
186 // Compute methods
187 int compute_for_parameters(bool is_static, CellTypeState *effect) {
188 _idx = 0;
189 _effect = effect;
190
191 if (!is_static)
192 effect[_idx++] = CellTypeState::make_slot_ref(0);
193
194 iterate_parameters();
195
196 return length();
197 };
198
199 int compute_for_returntype(CellTypeState *effect) {
200 _idx = 0;
201 _effect = effect;
202 iterate_returntype();
203 set(CellTypeState::bottom); // Always terminate with a bottom state, so ppush works
204
205 return length();
206 }
207 };
208
209 //=====================================================================================
210 //
211 // Implementation of RetTable/RetTableEntry
212 //
213 // Contains function to itereate through all bytecodes
214 // and find all return entry points
215 //
216 int RetTable::_init_nof_entries = 10;
217 int RetTableEntry::_init_nof_jsrs = 5;
218
219 void RetTableEntry::add_delta(int bci, int delta) {
220 if (_target_bci > bci) _target_bci += delta;
221
222 for (int k = 0; k < _jsrs->length(); k++) {
223 int jsr = _jsrs->at(k);
224 if (jsr > bci) _jsrs->at_put(k, jsr+delta);
225 }
226 }
227
228 void RetTable::compute_ret_table(const methodHandle& method) {
229 BytecodeStream i(method);
230 Bytecodes::Code bytecode;
231
232 while( (bytecode = i.next()) >= 0) {
233 switch (bytecode) {
234 case Bytecodes::_jsr:
235 add_jsr(i.next_bci(), i.dest());
236 break;
237 case Bytecodes::_jsr_w:
238 add_jsr(i.next_bci(), i.dest_w());
239 break;
240 }
241 }
242 }
243
244 void RetTable::add_jsr(int return_bci, int target_bci) {
245 RetTableEntry* entry = _first;
246
247 // Scan table for entry
248 for (;entry && entry->target_bci() != target_bci; entry = entry->next());
249
250 if (!entry) {
251 // Allocate new entry and put in list
252 entry = new RetTableEntry(target_bci, _first);
253 _first = entry;
254 }
255
256 // Now "entry" is set. Make sure that the entry is initialized
257 // and has room for the new jsr.
258 entry->add_jsr(return_bci);
259 }
260
261 RetTableEntry* RetTable::find_jsrs_for_target(int targBci) {
262 RetTableEntry *cur = _first;
263
264 while(cur) {
265 assert(cur->target_bci() != -1, "sanity check");
266 if (cur->target_bci() == targBci) return cur;
267 cur = cur->next();
268 }
269 ShouldNotReachHere();
270 return NULL;
271 }
272
273 // The instruction at bci is changing size by "delta". Update the return map.
274 void RetTable::update_ret_table(int bci, int delta) {
275 RetTableEntry *cur = _first;
276 while(cur) {
277 cur->add_delta(bci, delta);
278 cur = cur->next();
279 }
280 }
281
282 //
283 // Celltype state
284 //
285
286 CellTypeState CellTypeState::bottom = CellTypeState::make_bottom();
287 CellTypeState CellTypeState::uninit = CellTypeState::make_any(uninit_value);
288 CellTypeState CellTypeState::ref = CellTypeState::make_any(ref_conflict);
289 CellTypeState CellTypeState::value = CellTypeState::make_any(val_value);
290 CellTypeState CellTypeState::refUninit = CellTypeState::make_any(ref_conflict | uninit_value);
291 CellTypeState CellTypeState::top = CellTypeState::make_top();
292 CellTypeState CellTypeState::addr = CellTypeState::make_any(addr_conflict);
293
294 // Commonly used constants
295 static CellTypeState epsilonCTS[1] = { CellTypeState::bottom };
296 static CellTypeState refCTS = CellTypeState::ref;
297 static CellTypeState valCTS = CellTypeState::value;
298 static CellTypeState vCTS[2] = { CellTypeState::value, CellTypeState::bottom };
299 static CellTypeState rCTS[2] = { CellTypeState::ref, CellTypeState::bottom };
300 static CellTypeState rrCTS[3] = { CellTypeState::ref, CellTypeState::ref, CellTypeState::bottom };
301 static CellTypeState vrCTS[3] = { CellTypeState::value, CellTypeState::ref, CellTypeState::bottom };
302 static CellTypeState vvCTS[3] = { CellTypeState::value, CellTypeState::value, CellTypeState::bottom };
303 static CellTypeState rvrCTS[4] = { CellTypeState::ref, CellTypeState::value, CellTypeState::ref, CellTypeState::bottom };
304 static CellTypeState vvrCTS[4] = { CellTypeState::value, CellTypeState::value, CellTypeState::ref, CellTypeState::bottom };
305 static CellTypeState vvvCTS[4] = { CellTypeState::value, CellTypeState::value, CellTypeState::value, CellTypeState::bottom };
306 static CellTypeState vvvrCTS[5] = { CellTypeState::value, CellTypeState::value, CellTypeState::value, CellTypeState::ref, CellTypeState::bottom };
307 static CellTypeState vvvvCTS[5] = { CellTypeState::value, CellTypeState::value, CellTypeState::value, CellTypeState::value, CellTypeState::bottom };
308
309 char CellTypeState::to_char() const {
310 if (can_be_reference()) {
311 if (can_be_value() || can_be_address())
312 return '#'; // Conflict that needs to be rewritten
313 else
314 return 'r';
315 } else if (can_be_value())
316 return 'v';
317 else if (can_be_address())
318 return 'p';
319 else if (can_be_uninit())
320 return ' ';
321 else
322 return '@';
323 }
324
325
326 // Print a detailed CellTypeState. Indicate all bits that are set. If
327 // the CellTypeState represents an address or a reference, print the
328 // value of the additional information.
329 void CellTypeState::print(outputStream *os) {
330 if (can_be_address()) {
331 os->print("(p");
332 } else {
333 os->print("( ");
334 }
335 if (can_be_reference()) {
336 os->print("r");
337 } else {
338 os->print(" ");
339 }
340 if (can_be_value()) {
341 os->print("v");
342 } else {
343 os->print(" ");
344 }
345 if (can_be_uninit()) {
346 os->print("u|");
347 } else {
348 os->print(" |");
349 }
350 if (is_info_top()) {
351 os->print("Top)");
352 } else if (is_info_bottom()) {
353 os->print("Bot)");
354 } else {
355 if (is_reference()) {
356 int info = get_info();
357 int data = info & ~(ref_not_lock_bit | ref_slot_bit);
358 if (info & ref_not_lock_bit) {
359 // Not a monitor lock reference.
360 if (info & ref_slot_bit) {
361 // slot
362 os->print("slot%d)", data);
363 } else {
364 // line
365 os->print("line%d)", data);
366 }
367 } else {
368 // lock
369 os->print("lock%d)", data);
370 }
371 } else {
372 os->print("%d)", get_info());
373 }
374 }
375 }
376
377 //
378 // Basicblock handling methods
379 //
380
381 void GenerateOopMap::initialize_bb() {
382 _gc_points = 0;
383 _bb_count = 0;
384 _bb_hdr_bits.reinitialize(method()->code_size());
385 }
386
387 void GenerateOopMap::bb_mark_fct(GenerateOopMap *c, int bci, int *data) {
388 assert(bci>= 0 && bci < c->method()->code_size(), "index out of bounds");
389 if (c->is_bb_header(bci))
390 return;
391
392 if (TraceNewOopMapGeneration) {
393 tty->print_cr("Basicblock#%d begins at: %d", c->_bb_count, bci);
394 }
395 c->set_bbmark_bit(bci);
396 c->_bb_count++;
397 }
398
399
400 void GenerateOopMap::mark_bbheaders_and_count_gc_points() {
401 initialize_bb();
402
403 bool fellThrough = false; // False to get first BB marked.
404
405 // First mark all exception handlers as start of a basic-block
406 ExceptionTable excps(method());
407 for(int i = 0; i < excps.length(); i ++) {
408 bb_mark_fct(this, excps.handler_pc(i), NULL);
409 }
410
411 // Then iterate through the code
412 BytecodeStream bcs(_method);
413 Bytecodes::Code bytecode;
414
415 while( (bytecode = bcs.next()) >= 0) {
416 int bci = bcs.bci();
417
418 if (!fellThrough)
419 bb_mark_fct(this, bci, NULL);
420
421 fellThrough = jump_targets_do(&bcs, &GenerateOopMap::bb_mark_fct, NULL);
422
423 /* We will also mark successors of jsr's as basic block headers. */
424 switch (bytecode) {
425 case Bytecodes::_jsr:
426 assert(!fellThrough, "should not happen");
427 bb_mark_fct(this, bci + Bytecodes::length_for(bytecode), NULL);
428 break;
429 case Bytecodes::_jsr_w:
430 assert(!fellThrough, "should not happen");
431 bb_mark_fct(this, bci + Bytecodes::length_for(bytecode), NULL);
432 break;
433 }
434
435 if (possible_gc_point(&bcs))
436 _gc_points++;
437 }
438 }
439
440 inline void GenerateOopMap::set_bbmark_bit(int bci) {
441 _bb_hdr_bits.at_put(bci, true);
442 }
443
444 void GenerateOopMap::reachable_basicblock(GenerateOopMap *c, int bci, int *data) {
445 assert(bci>= 0 && bci < c->method()->code_size(), "index out of bounds");
446 BasicBlock* bb = c->get_basic_block_at(bci);
447 if (bb->is_dead()) {
448 bb->mark_as_alive();
449 *data = 1; // Mark basicblock as changed
450 }
451 }
452
453
454 void GenerateOopMap::mark_reachable_code() {
455 int change = 1; // int to get function pointers to work
456
457 // Mark entry basic block as alive and all exception handlers
458 _basic_blocks[0].mark_as_alive();
459 ExceptionTable excps(method());
460 for(int i = 0; i < excps.length(); i++) {
461 BasicBlock *bb = get_basic_block_at(excps.handler_pc(i));
462 // If block is not already alive (due to multiple exception handlers to same bb), then
463 // make it alive
464 if (bb->is_dead()) bb->mark_as_alive();
465 }
466
467 BytecodeStream bcs(_method);
468
469 // Iterate through all basic blocks until we reach a fixpoint
470 while (change) {
471 change = 0;
472
473 for (int i = 0; i < _bb_count; i++) {
474 BasicBlock *bb = &_basic_blocks[i];
475 if (bb->is_alive()) {
476 // Position bytecodestream at last bytecode in basicblock
477 bcs.set_start(bb->_end_bci);
478 bcs.next();
479 Bytecodes::Code bytecode = bcs.code();
480 int bci = bcs.bci();
481 assert(bci == bb->_end_bci, "wrong bci");
482
483 bool fell_through = jump_targets_do(&bcs, &GenerateOopMap::reachable_basicblock, &change);
484
485 // We will also mark successors of jsr's as alive.
486 switch (bytecode) {
487 case Bytecodes::_jsr:
488 case Bytecodes::_jsr_w:
489 assert(!fell_through, "should not happen");
490 reachable_basicblock(this, bci + Bytecodes::length_for(bytecode), &change);
491 break;
492 }
493 if (fell_through) {
494 // Mark successor as alive
495 if (bb[1].is_dead()) {
496 bb[1].mark_as_alive();
497 change = 1;
498 }
499 }
500 }
501 }
502 }
503 }
504
505 /* If the current instruction in "c" has no effect on control flow,
506 returns "true". Otherwise, calls "jmpFct" one or more times, with
507 "c", an appropriate "pcDelta", and "data" as arguments, then
508 returns "false". There is one exception: if the current
509 instruction is a "ret", returns "false" without calling "jmpFct".
510 Arrangements for tracking the control flow of a "ret" must be made
511 externally. */
512 bool GenerateOopMap::jump_targets_do(BytecodeStream *bcs, jmpFct_t jmpFct, int *data) {
513 int bci = bcs->bci();
514
515 switch (bcs->code()) {
516 case Bytecodes::_ifeq:
517 case Bytecodes::_ifne:
518 case Bytecodes::_iflt:
519 case Bytecodes::_ifge:
520 case Bytecodes::_ifgt:
521 case Bytecodes::_ifle:
522 case Bytecodes::_if_icmpeq:
523 case Bytecodes::_if_icmpne:
524 case Bytecodes::_if_icmplt:
525 case Bytecodes::_if_icmpge:
526 case Bytecodes::_if_icmpgt:
527 case Bytecodes::_if_icmple:
528 case Bytecodes::_if_acmpeq:
529 case Bytecodes::_if_acmpne:
530 case Bytecodes::_ifnull:
531 case Bytecodes::_ifnonnull:
532 (*jmpFct)(this, bcs->dest(), data);
533 (*jmpFct)(this, bci + 3, data);
534 break;
535
536 case Bytecodes::_goto:
537 (*jmpFct)(this, bcs->dest(), data);
538 break;
539 case Bytecodes::_goto_w:
540 (*jmpFct)(this, bcs->dest_w(), data);
541 break;
542 case Bytecodes::_tableswitch:
543 { Bytecode_tableswitch tableswitch(method(), bcs->bcp());
544 int len = tableswitch.length();
545
546 (*jmpFct)(this, bci + tableswitch.default_offset(), data); /* Default. jump address */
547 while (--len >= 0) {
548 (*jmpFct)(this, bci + tableswitch.dest_offset_at(len), data);
549 }
550 break;
551 }
552
553 case Bytecodes::_lookupswitch:
554 { Bytecode_lookupswitch lookupswitch(method(), bcs->bcp());
555 int npairs = lookupswitch.number_of_pairs();
556 (*jmpFct)(this, bci + lookupswitch.default_offset(), data); /* Default. */
557 while(--npairs >= 0) {
558 LookupswitchPair pair = lookupswitch.pair_at(npairs);
559 (*jmpFct)(this, bci + pair.offset(), data);
560 }
561 break;
562 }
563 case Bytecodes::_jsr:
564 assert(bcs->is_wide()==false, "sanity check");
565 (*jmpFct)(this, bcs->dest(), data);
566
567
568
569 break;
570 case Bytecodes::_jsr_w:
571 (*jmpFct)(this, bcs->dest_w(), data);
572 break;
573 case Bytecodes::_wide:
574 ShouldNotReachHere();
575 return true;
576 break;
577 case Bytecodes::_athrow:
578 case Bytecodes::_ireturn:
579 case Bytecodes::_lreturn:
580 case Bytecodes::_freturn:
581 case Bytecodes::_dreturn:
582 case Bytecodes::_areturn:
583 case Bytecodes::_return:
584 case Bytecodes::_ret:
585 break;
586 default:
587 return true;
588 }
589 return false;
590 }
591
592 /* Requires "pc" to be the head of a basic block; returns that basic
593 block. */
594 BasicBlock *GenerateOopMap::get_basic_block_at(int bci) const {
595 BasicBlock* bb = get_basic_block_containing(bci);
596 assert(bb->_bci == bci, "should have found BB");
597 return bb;
598 }
599
600 // Requires "pc" to be the start of an instruction; returns the basic
601 // block containing that instruction. */
602 BasicBlock *GenerateOopMap::get_basic_block_containing(int bci) const {
603 BasicBlock *bbs = _basic_blocks;
604 int lo = 0, hi = _bb_count - 1;
605
606 while (lo <= hi) {
607 int m = (lo + hi) / 2;
608 int mbci = bbs[m]._bci;
609 int nbci;
610
611 if ( m == _bb_count-1) {
612 assert( bci >= mbci && bci < method()->code_size(), "sanity check failed");
613 return bbs+m;
614 } else {
615 nbci = bbs[m+1]._bci;
616 }
617
618 if ( mbci <= bci && bci < nbci) {
619 return bbs+m;
620 } else if (mbci < bci) {
621 lo = m + 1;
622 } else {
623 assert(mbci > bci, "sanity check");
624 hi = m - 1;
625 }
626 }
627
628 fatal("should have found BB");
629 return NULL;
630 }
631
632 void GenerateOopMap::restore_state(BasicBlock *bb)
633 {
634 memcpy(_state, bb->_state, _state_len*sizeof(CellTypeState));
635 _stack_top = bb->_stack_top;
636 _monitor_top = bb->_monitor_top;
637 }
638
639 int GenerateOopMap::next_bb_start_pc(BasicBlock *bb) {
640 int bbNum = bb - _basic_blocks + 1;
641 if (bbNum == _bb_count)
642 return method()->code_size();
643
644 return _basic_blocks[bbNum]._bci;
645 }
646
647 //
648 // CellType handling methods
649 //
650
651 // Allocate memory and throw LinkageError if failure.
652 #define ALLOC_RESOURCE_ARRAY(var, type, count) \
653 var = NEW_RESOURCE_ARRAY_RETURN_NULL(type, count); \
654 if (var == NULL) { \
655 report_error("Cannot reserve enough memory to analyze this method"); \
656 return; \
657 }
658
659
660 void GenerateOopMap::init_state() {
661 _state_len = _max_locals + _max_stack + _max_monitors;
662 ALLOC_RESOURCE_ARRAY(_state, CellTypeState, _state_len);
663 memset(_state, 0, _state_len * sizeof(CellTypeState));
664 int count = MAX3(_max_locals, _max_stack, _max_monitors) + 1/*for null terminator char */;
665 ALLOC_RESOURCE_ARRAY(_state_vec_buf, char, count);
666 }
667
668 void GenerateOopMap::make_context_uninitialized() {
669 CellTypeState* vs = vars();
670
671 for (int i = 0; i < _max_locals; i++)
672 vs[i] = CellTypeState::uninit;
673
674 _stack_top = 0;
675 _monitor_top = 0;
676 }
677
678 int GenerateOopMap::methodsig_to_effect(Symbol* signature, bool is_static, CellTypeState* effect) {
679 ComputeEntryStack ces(signature);
680 return ces.compute_for_parameters(is_static, effect);
681 }
682
683 // Return result of merging cts1 and cts2.
684 CellTypeState CellTypeState::merge(CellTypeState cts, int slot) const {
685 CellTypeState result;
686
687 assert(!is_bottom() && !cts.is_bottom(),
688 "merge of bottom values is handled elsewhere");
689
690 result._state = _state | cts._state;
691
692 // If the top bit is set, we don't need to do any more work.
693 if (!result.is_info_top()) {
694 assert((result.can_be_address() || result.can_be_reference()),
695 "only addresses and references have non-top info");
696
697 if (!equal(cts)) {
698 // The two values being merged are different. Raise to top.
699 if (result.is_reference()) {
700 result = CellTypeState::make_slot_ref(slot);
701 } else {
702 result._state |= info_conflict;
703 }
704 }
705 }
706 assert(result.is_valid_state(), "checking that CTS merge maintains legal state");
707
708 return result;
709 }
710
711 // Merge the variable state for locals and stack from cts into bbts.
712 bool GenerateOopMap::merge_local_state_vectors(CellTypeState* cts,
713 CellTypeState* bbts) {
714 int i;
715 int len = _max_locals + _stack_top;
716 bool change = false;
717
718 for (i = len - 1; i >= 0; i--) {
719 CellTypeState v = cts[i].merge(bbts[i], i);
720 change = change || !v.equal(bbts[i]);
721 bbts[i] = v;
722 }
723
724 return change;
725 }
726
727 // Merge the monitor stack state from cts into bbts.
728 bool GenerateOopMap::merge_monitor_state_vectors(CellTypeState* cts,
729 CellTypeState* bbts) {
730 bool change = false;
731 if (_max_monitors > 0 && _monitor_top != bad_monitors) {
732 // If there are no monitors in the program, or there has been
733 // a monitor matching error before this point in the program,
734 // then we do not merge in the monitor state.
735
736 int base = _max_locals + _max_stack;
737 int len = base + _monitor_top;
738 for (int i = len - 1; i >= base; i--) {
739 CellTypeState v = cts[i].merge(bbts[i], i);
740
741 // Can we prove that, when there has been a change, it will already
742 // have been detected at this point? That would make this equal
743 // check here unnecessary.
744 change = change || !v.equal(bbts[i]);
745 bbts[i] = v;
746 }
747 }
748
749 return change;
750 }
751
752 void GenerateOopMap::copy_state(CellTypeState *dst, CellTypeState *src) {
753 int len = _max_locals + _stack_top;
754 for (int i = 0; i < len; i++) {
755 if (src[i].is_nonlock_reference()) {
756 dst[i] = CellTypeState::make_slot_ref(i);
757 } else {
758 dst[i] = src[i];
759 }
760 }
761 if (_max_monitors > 0 && _monitor_top != bad_monitors) {
762 int base = _max_locals + _max_stack;
763 len = base + _monitor_top;
764 for (int i = base; i < len; i++) {
765 dst[i] = src[i];
766 }
767 }
768 }
769
770
771 // Merge the states for the current block and the next. As long as a
772 // block is reachable the locals and stack must be merged. If the
773 // stack heights don't match then this is a verification error and
774 // it's impossible to interpret the code. Simultaneously monitor
775 // states are being check to see if they nest statically. If monitor
776 // depths match up then their states are merged. Otherwise the
777 // mismatch is simply recorded and interpretation continues since
778 // monitor matching is purely informational and doesn't say anything
779 // about the correctness of the code.
780 void GenerateOopMap::merge_state_into_bb(BasicBlock *bb) {
781 guarantee(bb != NULL, "null basicblock");
782 assert(bb->is_alive(), "merging state into a dead basicblock");
783
784 if (_stack_top == bb->_stack_top) {
785 // always merge local state even if monitors don't match.
786 if (merge_local_state_vectors(_state, bb->_state)) {
787 bb->set_changed(true);
788 }
789 if (_monitor_top == bb->_monitor_top) {
790 // monitors still match so continue merging monitor states.
791 if (merge_monitor_state_vectors(_state, bb->_state)) {
792 bb->set_changed(true);
793 }
794 } else {
795 if (log_is_enabled(Info, monitormismatch)) {
796 report_monitor_mismatch("monitor stack height merge conflict");
797 }
798 // When the monitor stacks are not matched, we set _monitor_top to
799 // bad_monitors. This signals that, from here on, the monitor stack cannot
800 // be trusted. In particular, monitorexit bytecodes may throw
801 // exceptions. We mark this block as changed so that the change
802 // propagates properly.
803 bb->_monitor_top = bad_monitors;
804 bb->set_changed(true);
805 _monitor_safe = false;
806 }
807 } else if (!bb->is_reachable()) {
808 // First time we look at this BB
809 copy_state(bb->_state, _state);
810 bb->_stack_top = _stack_top;
811 bb->_monitor_top = _monitor_top;
812 bb->set_changed(true);
813 } else {
814 verify_error("stack height conflict: %d vs. %d", _stack_top, bb->_stack_top);
815 }
816 }
817
818 void GenerateOopMap::merge_state(GenerateOopMap *gom, int bci, int* data) {
819 gom->merge_state_into_bb(gom->get_basic_block_at(bci));
820 }
821
822 void GenerateOopMap::set_var(int localNo, CellTypeState cts) {
823 assert(cts.is_reference() || cts.is_value() || cts.is_address(),
824 "wrong celltypestate");
825 if (localNo < 0 || localNo > _max_locals) {
826 verify_error("variable write error: r%d", localNo);
827 return;
828 }
829 vars()[localNo] = cts;
830 }
831
832 CellTypeState GenerateOopMap::get_var(int localNo) {
833 assert(localNo < _max_locals + _nof_refval_conflicts, "variable read error");
834 if (localNo < 0 || localNo > _max_locals) {
835 verify_error("variable read error: r%d", localNo);
836 return valCTS; // just to pick something;
837 }
838 return vars()[localNo];
839 }
840
841 CellTypeState GenerateOopMap::pop() {
842 if ( _stack_top <= 0) {
843 verify_error("stack underflow");
844 return valCTS; // just to pick something
845 }
846 return stack()[--_stack_top];
847 }
848
849 void GenerateOopMap::push(CellTypeState cts) {
850 if ( _stack_top >= _max_stack) {
851 verify_error("stack overflow");
852 return;
853 }
854 stack()[_stack_top++] = cts;
855 }
856
857 CellTypeState GenerateOopMap::monitor_pop() {
858 assert(_monitor_top != bad_monitors, "monitor_pop called on error monitor stack");
859 if (_monitor_top == 0) {
860 // We have detected a pop of an empty monitor stack.
861 _monitor_safe = false;
862 _monitor_top = bad_monitors;
863
864 if (log_is_enabled(Info, monitormismatch)) {
865 report_monitor_mismatch("monitor stack underflow");
866 }
867 return CellTypeState::ref; // just to keep the analysis going.
868 }
869 return monitors()[--_monitor_top];
870 }
871
872 void GenerateOopMap::monitor_push(CellTypeState cts) {
873 assert(_monitor_top != bad_monitors, "monitor_push called on error monitor stack");
874 if (_monitor_top >= _max_monitors) {
875 // Some monitorenter is being executed more than once.
876 // This means that the monitor stack cannot be simulated.
877 _monitor_safe = false;
878 _monitor_top = bad_monitors;
879
880 if (log_is_enabled(Info, monitormismatch)) {
881 report_monitor_mismatch("monitor stack overflow");
882 }
883 return;
884 }
885 monitors()[_monitor_top++] = cts;
886 }
887
888 //
889 // Interpretation handling methods
890 //
891
892 void GenerateOopMap::do_interpretation()
893 {
894 // "i" is just for debugging, so we can detect cases where this loop is
895 // iterated more than once.
896 int i = 0;
897 do {
898 #ifndef PRODUCT
899 if (TraceNewOopMapGeneration) {
900 tty->print("\n\nIteration #%d of do_interpretation loop, method:\n", i);
901 method()->print_name(tty);
902 tty->print("\n\n");
903 }
904 #endif
905 _conflict = false;
906 _monitor_safe = true;
907 // init_state is now called from init_basic_blocks. The length of a
908 // state vector cannot be determined until we have made a pass through
909 // the bytecodes counting the possible monitor entries.
910 if (!_got_error) init_basic_blocks();
911 if (!_got_error) setup_method_entry_state();
912 if (!_got_error) interp_all();
913 if (!_got_error) rewrite_refval_conflicts();
914 i++;
915 } while (_conflict && !_got_error);
916 }
917
918 void GenerateOopMap::init_basic_blocks() {
919 // Note: Could consider reserving only the needed space for each BB's state
920 // (entry stack may not be of maximal height for every basic block).
921 // But cumbersome since we don't know the stack heights yet. (Nor the
922 // monitor stack heights...)
923
924 ALLOC_RESOURCE_ARRAY(_basic_blocks, BasicBlock, _bb_count);
925
926 // Make a pass through the bytecodes. Count the number of monitorenters.
927 // This can be used an upper bound on the monitor stack depth in programs
928 // which obey stack discipline with their monitor usage. Initialize the
929 // known information about basic blocks.
930 BytecodeStream j(_method);
931 Bytecodes::Code bytecode;
932
933 int bbNo = 0;
934 int monitor_count = 0;
935 int prev_bci = -1;
936 while( (bytecode = j.next()) >= 0) {
937 if (j.code() == Bytecodes::_monitorenter) {
938 monitor_count++;
939 }
940
941 int bci = j.bci();
942 if (is_bb_header(bci)) {
943 // Initialize the basicblock structure
944 BasicBlock *bb = _basic_blocks + bbNo;
945 bb->_bci = bci;
946 bb->_max_locals = _max_locals;
947 bb->_max_stack = _max_stack;
948 bb->set_changed(false);
949 bb->_stack_top = BasicBlock::_dead_basic_block; // Initialize all basicblocks are dead.
950 bb->_monitor_top = bad_monitors;
951
952 if (bbNo > 0) {
953 _basic_blocks[bbNo - 1]._end_bci = prev_bci;
954 }
955
956 bbNo++;
957 }
958 // Remember prevous bci.
959 prev_bci = bci;
960 }
961 // Set
962 _basic_blocks[bbNo-1]._end_bci = prev_bci;
963
964
965 // Check that the correct number of basicblocks was found
966 if (bbNo !=_bb_count) {
967 if (bbNo < _bb_count) {
968 verify_error("jump into the middle of instruction?");
969 return;
970 } else {
971 verify_error("extra basic blocks - should not happen?");
972 return;
973 }
974 }
975
976 _max_monitors = monitor_count;
977
978 // Now that we have a bound on the depth of the monitor stack, we can
979 // initialize the CellTypeState-related information.
980 init_state();
981
982 // We allocate space for all state-vectors for all basicblocks in one huge
983 // chunk. Then in the next part of the code, we set a pointer in each
984 // _basic_block that points to each piece.
985
986 // The product of bbNo and _state_len can get large if there are lots of
987 // basic blocks and stack/locals/monitors. Need to check to make sure
988 // we don't overflow the capacity of a pointer.
989 if ((unsigned)bbNo > UINTPTR_MAX / sizeof(CellTypeState) / _state_len) {
990 report_error("The amount of memory required to analyze this method "
991 "exceeds addressable range");
992 return;
993 }
994
995 CellTypeState *basicBlockState;
996 ALLOC_RESOURCE_ARRAY(basicBlockState, CellTypeState, bbNo * _state_len);
997 memset(basicBlockState, 0, bbNo * _state_len * sizeof(CellTypeState));
998
999 // Make a pass over the basicblocks and assign their state vectors.
1000 for (int blockNum=0; blockNum < bbNo; blockNum++) {
1001 BasicBlock *bb = _basic_blocks + blockNum;
1002 bb->_state = basicBlockState + blockNum * _state_len;
1003
1004 #ifdef ASSERT
1005 if (blockNum + 1 < bbNo) {
1006 address bcp = _method->bcp_from(bb->_end_bci);
1007 int bc_len = Bytecodes::java_length_at(_method(), bcp);
1008 assert(bb->_end_bci + bc_len == bb[1]._bci, "unmatched bci info in basicblock");
1009 }
1010 #endif
1011 }
1012 #ifdef ASSERT
1013 { BasicBlock *bb = &_basic_blocks[bbNo-1];
1014 address bcp = _method->bcp_from(bb->_end_bci);
1015 int bc_len = Bytecodes::java_length_at(_method(), bcp);
1016 assert(bb->_end_bci + bc_len == _method->code_size(), "wrong end bci");
1017 }
1018 #endif
1019
1020 // Mark all alive blocks
1021 mark_reachable_code();
1022 }
1023
1024 void GenerateOopMap::setup_method_entry_state() {
1025
1026 // Initialize all locals to 'uninit' and set stack-height to 0
1027 make_context_uninitialized();
1028
1029 // Initialize CellState type of arguments
1030 methodsig_to_effect(method()->signature(), method()->is_static(), vars());
1031
1032 // If some references must be pre-assigned to null, then set that up
1033 initialize_vars();
1034
1035 // This is the start state
1036 merge_state_into_bb(&_basic_blocks[0]);
1037
1038 assert(_basic_blocks[0].changed(), "we are not getting off the ground");
1039 }
1040
1041 // The instruction at bci is changing size by "delta". Update the basic blocks.
1042 void GenerateOopMap::update_basic_blocks(int bci, int delta,
1043 int new_method_size) {
1044 assert(new_method_size >= method()->code_size() + delta,
1045 "new method size is too small");
1046
1047 _bb_hdr_bits.reinitialize(new_method_size);
1048
1049 for(int k = 0; k < _bb_count; k++) {
1050 if (_basic_blocks[k]._bci > bci) {
1051 _basic_blocks[k]._bci += delta;
1052 _basic_blocks[k]._end_bci += delta;
1053 }
1054 _bb_hdr_bits.at_put(_basic_blocks[k]._bci, true);
1055 }
1056 }
1057
1058 //
1059 // Initvars handling
1060 //
1061
1062 void GenerateOopMap::initialize_vars() {
1063 for (int k = 0; k < _init_vars->length(); k++)
1064 _state[_init_vars->at(k)] = CellTypeState::make_slot_ref(k);
1065 }
1066
1067 void GenerateOopMap::add_to_ref_init_set(int localNo) {
1068
1069 if (TraceNewOopMapGeneration)
1070 tty->print_cr("Added init vars: %d", localNo);
1071
1072 // Is it already in the set?
1073 if (_init_vars->contains(localNo) )
1074 return;
1075
1076 _init_vars->append(localNo);
1077 }
1078
1079 //
1080 // Interpreration code
1081 //
1082
1083 void GenerateOopMap::interp_all() {
1084 bool change = true;
1085
1086 while (change && !_got_error) {
1087 change = false;
1088 for (int i = 0; i < _bb_count && !_got_error; i++) {
1089 BasicBlock *bb = &_basic_blocks[i];
1090 if (bb->changed()) {
1091 if (_got_error) return;
1092 change = true;
1093 bb->set_changed(false);
1094 interp_bb(bb);
1095 }
1096 }
1097 }
1098 }
1099
1100 void GenerateOopMap::interp_bb(BasicBlock *bb) {
1101
1102 // We do not want to do anything in case the basic-block has not been initialized. This
1103 // will happen in the case where there is dead-code hang around in a method.
1104 assert(bb->is_reachable(), "should be reachable or deadcode exist");
1105 restore_state(bb);
1106
1107 BytecodeStream itr(_method);
1108
1109 // Set iterator interval to be the current basicblock
1110 int lim_bci = next_bb_start_pc(bb);
1111 itr.set_interval(bb->_bci, lim_bci);
1112 assert(lim_bci != bb->_bci, "must be at least one instruction in a basicblock");
1113 itr.next(); // read first instruction
1114
1115 // Iterates through all bytecodes except the last in a basic block.
1116 // We handle the last one special, since there is controlflow change.
1117 while(itr.next_bci() < lim_bci && !_got_error) {
1118 if (_has_exceptions || _monitor_top != 0) {
1119 // We do not need to interpret the results of exceptional
1120 // continuation from this instruction when the method has no
1121 // exception handlers and the monitor stack is currently
1122 // empty.
1123 do_exception_edge(&itr);
1124 }
1125 interp1(&itr);
1126 itr.next();
1127 }
1128
1129 // Handle last instruction.
1130 if (!_got_error) {
1131 assert(itr.next_bci() == lim_bci, "must point to end");
1132 if (_has_exceptions || _monitor_top != 0) {
1133 do_exception_edge(&itr);
1134 }
1135 interp1(&itr);
1136
1137 bool fall_through = jump_targets_do(&itr, GenerateOopMap::merge_state, NULL);
1138 if (_got_error) return;
1139
1140 if (itr.code() == Bytecodes::_ret) {
1141 assert(!fall_through, "cannot be set if ret instruction");
1142 // Automatically handles 'wide' ret indicies
1143 ret_jump_targets_do(&itr, GenerateOopMap::merge_state, itr.get_index(), NULL);
1144 } else if (fall_through) {
1145 // Hit end of BB, but the instr. was a fall-through instruction,
1146 // so perform transition as if the BB ended in a "jump".
1147 if (lim_bci != bb[1]._bci) {
1148 verify_error("bytecodes fell through last instruction");
1149 return;
1150 }
1151 merge_state_into_bb(bb + 1);
1152 }
1153 }
1154 }
1155
1156 void GenerateOopMap::do_exception_edge(BytecodeStream* itr) {
1157 // Only check exception edge, if bytecode can trap
1158 if (!Bytecodes::can_trap(itr->code())) return;
1159 switch (itr->code()) {
1160 case Bytecodes::_aload_0:
1161 // These bytecodes can trap for rewriting. We need to assume that
1162 // they do not throw exceptions to make the monitor analysis work.
1163 return;
1164
1165 case Bytecodes::_ireturn:
1166 case Bytecodes::_lreturn:
1167 case Bytecodes::_freturn:
1168 case Bytecodes::_dreturn:
1169 case Bytecodes::_areturn:
1170 case Bytecodes::_return:
1171 // If the monitor stack height is not zero when we leave the method,
1172 // then we are either exiting with a non-empty stack or we have
1173 // found monitor trouble earlier in our analysis. In either case,
1174 // assume an exception could be taken here.
1175 if (_monitor_top == 0) {
1176 return;
1177 }
1178 break;
1179
1180 case Bytecodes::_monitorexit:
1181 // If the monitor stack height is bad_monitors, then we have detected a
1182 // monitor matching problem earlier in the analysis. If the
1183 // monitor stack height is 0, we are about to pop a monitor
1184 // off of an empty stack. In either case, the bytecode
1185 // could throw an exception.
1186 if (_monitor_top != bad_monitors && _monitor_top != 0) {
1187 return;
1188 }
1189 break;
1190 }
1191
1192 if (_has_exceptions) {
1193 int bci = itr->bci();
1194 ExceptionTable exct(method());
1195 for(int i = 0; i< exct.length(); i++) {
1196 int start_pc = exct.start_pc(i);
1197 int end_pc = exct.end_pc(i);
1198 int handler_pc = exct.handler_pc(i);
1199 int catch_type = exct.catch_type_index(i);
1200
1201 if (start_pc <= bci && bci < end_pc) {
1202 BasicBlock *excBB = get_basic_block_at(handler_pc);
1203 guarantee(excBB != NULL, "no basic block for exception");
1204 CellTypeState *excStk = excBB->stack();
1205 CellTypeState *cOpStck = stack();
1206 CellTypeState cOpStck_0 = cOpStck[0];
1207 int cOpStackTop = _stack_top;
1208
1209 // Exception stacks are always the same.
1210 assert(method()->max_stack() > 0, "sanity check");
1211
1212 // We remembered the size and first element of "cOpStck"
1213 // above; now we temporarily set them to the appropriate
1214 // values for an exception handler. */
1215 cOpStck[0] = CellTypeState::make_slot_ref(_max_locals);
1216 _stack_top = 1;
1217
1218 merge_state_into_bb(excBB);
1219
1220 // Now undo the temporary change.
1221 cOpStck[0] = cOpStck_0;
1222 _stack_top = cOpStackTop;
1223
1224 // If this is a "catch all" handler, then we do not need to
1225 // consider any additional handlers.
1226 if (catch_type == 0) {
1227 return;
1228 }
1229 }
1230 }
1231 }
1232
1233 // It is possible that none of the exception handlers would have caught
1234 // the exception. In this case, we will exit the method. We must
1235 // ensure that the monitor stack is empty in this case.
1236 if (_monitor_top == 0) {
1237 return;
1238 }
1239
1240 // We pessimistically assume that this exception can escape the
1241 // method. (It is possible that it will always be caught, but
1242 // we don't care to analyse the types of the catch clauses.)
1243
1244 // We don't set _monitor_top to bad_monitors because there are no successors
1245 // to this exceptional exit.
1246
1247 if (log_is_enabled(Info, monitormismatch) && _monitor_safe) {
1248 // We check _monitor_safe so that we only report the first mismatched
1249 // exceptional exit.
1250 report_monitor_mismatch("non-empty monitor stack at exceptional exit");
1251 }
1252 _monitor_safe = false;
1253
1254 }
1255
1256 void GenerateOopMap::report_monitor_mismatch(const char *msg) {
1257 ResourceMark rm;
1258 outputStream* out = Log(monitormismatch)::info_stream();
1259 out->print("Monitor mismatch in method ");
1260 method()->print_short_name(out);
1261 out->print_cr(": %s", msg);
1262 }
1263
1264 void GenerateOopMap::print_states(outputStream *os,
1265 CellTypeState* vec, int num) {
1266 for (int i = 0; i < num; i++) {
1267 vec[i].print(tty);
1268 }
1269 }
1270
1271 // Print the state values at the current bytecode.
1272 void GenerateOopMap::print_current_state(outputStream *os,
1273 BytecodeStream *currentBC,
1274 bool detailed) {
1275
1276 if (detailed) {
1277 os->print(" %4d vars = ", currentBC->bci());
1278 print_states(os, vars(), _max_locals);
1279 os->print(" %s", Bytecodes::name(currentBC->code()));
1280 switch(currentBC->code()) {
1281 case Bytecodes::_invokevirtual:
1282 case Bytecodes::_invokespecial:
1283 case Bytecodes::_invokestatic:
1284 case Bytecodes::_invokedynamic:
1285 case Bytecodes::_invokeinterface:
1286 int idx = currentBC->has_index_u4() ? currentBC->get_index_u4() : currentBC->get_index_u2_cpcache();
1287 ConstantPool* cp = method()->constants();
1288 int nameAndTypeIdx = cp->name_and_type_ref_index_at(idx);
1289 int signatureIdx = cp->signature_ref_index_at(nameAndTypeIdx);
1290 Symbol* signature = cp->symbol_at(signatureIdx);
1291 os->print("%s", signature->as_C_string());
1292 }
1293 os->cr();
1294 os->print(" stack = ");
1295 print_states(os, stack(), _stack_top);
1296 os->cr();
1297 if (_monitor_top != bad_monitors) {
1298 os->print(" monitors = ");
1299 print_states(os, monitors(), _monitor_top);
1300 } else {
1301 os->print(" [bad monitor stack]");
1302 }
1303 os->cr();
1304 } else {
1305 os->print(" %4d vars = '%s' ", currentBC->bci(), state_vec_to_string(vars(), _max_locals));
1306 os->print(" stack = '%s' ", state_vec_to_string(stack(), _stack_top));
1307 if (_monitor_top != bad_monitors) {
1308 os->print(" monitors = '%s' \t%s", state_vec_to_string(monitors(), _monitor_top), Bytecodes::name(currentBC->code()));
1309 } else {
1310 os->print(" [bad monitor stack]");
1311 }
1312 switch(currentBC->code()) {
1313 case Bytecodes::_invokevirtual:
1314 case Bytecodes::_invokespecial:
1315 case Bytecodes::_invokestatic:
1316 case Bytecodes::_invokedynamic:
1317 case Bytecodes::_invokeinterface:
1318 int idx = currentBC->has_index_u4() ? currentBC->get_index_u4() : currentBC->get_index_u2_cpcache();
1319 ConstantPool* cp = method()->constants();
1320 int nameAndTypeIdx = cp->name_and_type_ref_index_at(idx);
1321 int signatureIdx = cp->signature_ref_index_at(nameAndTypeIdx);
1322 Symbol* signature = cp->symbol_at(signatureIdx);
1323 os->print("%s", signature->as_C_string());
1324 }
1325 os->cr();
1326 }
1327 }
1328
1329 // Sets the current state to be the state after executing the
1330 // current instruction, starting in the current state.
1331 void GenerateOopMap::interp1(BytecodeStream *itr) {
1332 if (TraceNewOopMapGeneration) {
1333 print_current_state(tty, itr, TraceNewOopMapGenerationDetailed);
1334 }
1335
1336 // Should we report the results? Result is reported *before* the instruction at the current bci is executed.
1337 // However, not for calls. For calls we do not want to include the arguments, so we postpone the reporting until
1338 // they have been popped (in method ppl).
1339 if (_report_result == true) {
1340 switch(itr->code()) {
1341 case Bytecodes::_invokevirtual:
1342 case Bytecodes::_invokespecial:
1343 case Bytecodes::_invokestatic:
1344 case Bytecodes::_invokedynamic:
1345 case Bytecodes::_invokeinterface:
1346 _itr_send = itr;
1347 _report_result_for_send = true;
1348 break;
1349 default:
1350 fill_stackmap_for_opcodes(itr, vars(), stack(), _stack_top);
1351 break;
1352 }
1353 }
1354
1355 // abstract interpretation of current opcode
1356 switch(itr->code()) {
1357 case Bytecodes::_nop: break;
1358 case Bytecodes::_goto: break;
1359 case Bytecodes::_goto_w: break;
1360 case Bytecodes::_iinc: break;
1361 case Bytecodes::_return: do_return_monitor_check();
1362 break;
1363
1364 case Bytecodes::_aconst_null:
1365 case Bytecodes::_new: ppush1(CellTypeState::make_line_ref(itr->bci()));
1366 break;
1367
1368 case Bytecodes::_iconst_m1:
1369 case Bytecodes::_iconst_0:
1370 case Bytecodes::_iconst_1:
1371 case Bytecodes::_iconst_2:
1372 case Bytecodes::_iconst_3:
1373 case Bytecodes::_iconst_4:
1374 case Bytecodes::_iconst_5:
1375 case Bytecodes::_fconst_0:
1376 case Bytecodes::_fconst_1:
1377 case Bytecodes::_fconst_2:
1378 case Bytecodes::_bipush:
1379 case Bytecodes::_sipush: ppush1(valCTS); break;
1380
1381 case Bytecodes::_lconst_0:
1382 case Bytecodes::_lconst_1:
1383 case Bytecodes::_dconst_0:
1384 case Bytecodes::_dconst_1: ppush(vvCTS); break;
1385
1386 case Bytecodes::_ldc2_w: ppush(vvCTS); break;
1387
1388 case Bytecodes::_ldc: // fall through:
1389 case Bytecodes::_ldc_w: do_ldc(itr->bci()); break;
1390
1391 case Bytecodes::_iload:
1392 case Bytecodes::_fload: ppload(vCTS, itr->get_index()); break;
1393
1394 case Bytecodes::_lload:
1395 case Bytecodes::_dload: ppload(vvCTS,itr->get_index()); break;
1396
1397 case Bytecodes::_aload: ppload(rCTS, itr->get_index()); break;
1398
1399 case Bytecodes::_iload_0:
1400 case Bytecodes::_fload_0: ppload(vCTS, 0); break;
1401 case Bytecodes::_iload_1:
1402 case Bytecodes::_fload_1: ppload(vCTS, 1); break;
1403 case Bytecodes::_iload_2:
1404 case Bytecodes::_fload_2: ppload(vCTS, 2); break;
1405 case Bytecodes::_iload_3:
1406 case Bytecodes::_fload_3: ppload(vCTS, 3); break;
1407
1408 case Bytecodes::_lload_0:
1409 case Bytecodes::_dload_0: ppload(vvCTS, 0); break;
1410 case Bytecodes::_lload_1:
1411 case Bytecodes::_dload_1: ppload(vvCTS, 1); break;
1412 case Bytecodes::_lload_2:
1413 case Bytecodes::_dload_2: ppload(vvCTS, 2); break;
1414 case Bytecodes::_lload_3:
1415 case Bytecodes::_dload_3: ppload(vvCTS, 3); break;
1416
1417 case Bytecodes::_aload_0: ppload(rCTS, 0); break;
1418 case Bytecodes::_aload_1: ppload(rCTS, 1); break;
1419 case Bytecodes::_aload_2: ppload(rCTS, 2); break;
1420 case Bytecodes::_aload_3: ppload(rCTS, 3); break;
1421
1422 case Bytecodes::_iaload:
1423 case Bytecodes::_faload:
1424 case Bytecodes::_baload:
1425 case Bytecodes::_caload:
1426 case Bytecodes::_saload: pp(vrCTS, vCTS); break;
1427
1428 case Bytecodes::_laload: pp(vrCTS, vvCTS); break;
1429 case Bytecodes::_daload: pp(vrCTS, vvCTS); break;
1430
1431 case Bytecodes::_aaload: pp_new_ref(vrCTS, itr->bci()); break;
1432
1433 case Bytecodes::_istore:
1434 case Bytecodes::_fstore: ppstore(vCTS, itr->get_index()); break;
1435
1436 case Bytecodes::_lstore:
1437 case Bytecodes::_dstore: ppstore(vvCTS, itr->get_index()); break;
1438
1439 case Bytecodes::_astore: do_astore(itr->get_index()); break;
1440
1441 case Bytecodes::_istore_0:
1442 case Bytecodes::_fstore_0: ppstore(vCTS, 0); break;
1443 case Bytecodes::_istore_1:
1444 case Bytecodes::_fstore_1: ppstore(vCTS, 1); break;
1445 case Bytecodes::_istore_2:
1446 case Bytecodes::_fstore_2: ppstore(vCTS, 2); break;
1447 case Bytecodes::_istore_3:
1448 case Bytecodes::_fstore_3: ppstore(vCTS, 3); break;
1449
1450 case Bytecodes::_lstore_0:
1451 case Bytecodes::_dstore_0: ppstore(vvCTS, 0); break;
1452 case Bytecodes::_lstore_1:
1453 case Bytecodes::_dstore_1: ppstore(vvCTS, 1); break;
1454 case Bytecodes::_lstore_2:
1455 case Bytecodes::_dstore_2: ppstore(vvCTS, 2); break;
1456 case Bytecodes::_lstore_3:
1457 case Bytecodes::_dstore_3: ppstore(vvCTS, 3); break;
1458
1459 case Bytecodes::_astore_0: do_astore(0); break;
1460 case Bytecodes::_astore_1: do_astore(1); break;
1461 case Bytecodes::_astore_2: do_astore(2); break;
1462 case Bytecodes::_astore_3: do_astore(3); break;
1463
1464 case Bytecodes::_iastore:
1465 case Bytecodes::_fastore:
1466 case Bytecodes::_bastore:
1467 case Bytecodes::_castore:
1468 case Bytecodes::_sastore: ppop(vvrCTS); break;
1469 case Bytecodes::_lastore:
1470 case Bytecodes::_dastore: ppop(vvvrCTS); break;
1471 case Bytecodes::_aastore: ppop(rvrCTS); break;
1472
1473 case Bytecodes::_pop: ppop_any(1); break;
1474 case Bytecodes::_pop2: ppop_any(2); break;
1475
1476 case Bytecodes::_dup: ppdupswap(1, "11"); break;
1477 case Bytecodes::_dup_x1: ppdupswap(2, "121"); break;
1478 case Bytecodes::_dup_x2: ppdupswap(3, "1321"); break;
1479 case Bytecodes::_dup2: ppdupswap(2, "2121"); break;
1480 case Bytecodes::_dup2_x1: ppdupswap(3, "21321"); break;
1481 case Bytecodes::_dup2_x2: ppdupswap(4, "214321"); break;
1482 case Bytecodes::_swap: ppdupswap(2, "12"); break;
1483
1484 case Bytecodes::_iadd:
1485 case Bytecodes::_fadd:
1486 case Bytecodes::_isub:
1487 case Bytecodes::_fsub:
1488 case Bytecodes::_imul:
1489 case Bytecodes::_fmul:
1490 case Bytecodes::_idiv:
1491 case Bytecodes::_fdiv:
1492 case Bytecodes::_irem:
1493 case Bytecodes::_frem:
1494 case Bytecodes::_ishl:
1495 case Bytecodes::_ishr:
1496 case Bytecodes::_iushr:
1497 case Bytecodes::_iand:
1498 case Bytecodes::_ior:
1499 case Bytecodes::_ixor:
1500 case Bytecodes::_l2f:
1501 case Bytecodes::_l2i:
1502 case Bytecodes::_d2f:
1503 case Bytecodes::_d2i:
1504 case Bytecodes::_fcmpl:
1505 case Bytecodes::_fcmpg: pp(vvCTS, vCTS); break;
1506
1507 case Bytecodes::_ladd:
1508 case Bytecodes::_dadd:
1509 case Bytecodes::_lsub:
1510 case Bytecodes::_dsub:
1511 case Bytecodes::_lmul:
1512 case Bytecodes::_dmul:
1513 case Bytecodes::_ldiv:
1514 case Bytecodes::_ddiv:
1515 case Bytecodes::_lrem:
1516 case Bytecodes::_drem:
1517 case Bytecodes::_land:
1518 case Bytecodes::_lor:
1519 case Bytecodes::_lxor: pp(vvvvCTS, vvCTS); break;
1520
1521 case Bytecodes::_ineg:
1522 case Bytecodes::_fneg:
1523 case Bytecodes::_i2f:
1524 case Bytecodes::_f2i:
1525 case Bytecodes::_i2c:
1526 case Bytecodes::_i2s:
1527 case Bytecodes::_i2b: pp(vCTS, vCTS); break;
1528
1529 case Bytecodes::_lneg:
1530 case Bytecodes::_dneg:
1531 case Bytecodes::_l2d:
1532 case Bytecodes::_d2l: pp(vvCTS, vvCTS); break;
1533
1534 case Bytecodes::_lshl:
1535 case Bytecodes::_lshr:
1536 case Bytecodes::_lushr: pp(vvvCTS, vvCTS); break;
1537
1538 case Bytecodes::_i2l:
1539 case Bytecodes::_i2d:
1540 case Bytecodes::_f2l:
1541 case Bytecodes::_f2d: pp(vCTS, vvCTS); break;
1542
1543 case Bytecodes::_lcmp: pp(vvvvCTS, vCTS); break;
1544 case Bytecodes::_dcmpl:
1545 case Bytecodes::_dcmpg: pp(vvvvCTS, vCTS); break;
1546
1547 case Bytecodes::_ifeq:
1548 case Bytecodes::_ifne:
1549 case Bytecodes::_iflt:
1550 case Bytecodes::_ifge:
1551 case Bytecodes::_ifgt:
1552 case Bytecodes::_ifle:
1553 case Bytecodes::_tableswitch: ppop1(valCTS);
1554 break;
1555 case Bytecodes::_ireturn:
1556 case Bytecodes::_freturn: do_return_monitor_check();
1557 ppop1(valCTS);
1558 break;
1559 case Bytecodes::_if_icmpeq:
1560 case Bytecodes::_if_icmpne:
1561 case Bytecodes::_if_icmplt:
1562 case Bytecodes::_if_icmpge:
1563 case Bytecodes::_if_icmpgt:
1564 case Bytecodes::_if_icmple: ppop(vvCTS);
1565 break;
1566
1567 case Bytecodes::_lreturn: do_return_monitor_check();
1568 ppop(vvCTS);
1569 break;
1570
1571 case Bytecodes::_dreturn: do_return_monitor_check();
1572 ppop(vvCTS);
1573 break;
1574
1575 case Bytecodes::_if_acmpeq:
1576 case Bytecodes::_if_acmpne: ppop(rrCTS); break;
1577
1578 case Bytecodes::_jsr: do_jsr(itr->dest()); break;
1579 case Bytecodes::_jsr_w: do_jsr(itr->dest_w()); break;
1580
1581 case Bytecodes::_getstatic: do_field(true, true, itr->get_index_u2_cpcache(), itr->bci()); break;
1582 case Bytecodes::_putstatic: do_field(false, true, itr->get_index_u2_cpcache(), itr->bci()); break;
1583 case Bytecodes::_getfield: do_field(true, false, itr->get_index_u2_cpcache(), itr->bci()); break;
1584 case Bytecodes::_putfield: do_field(false, false, itr->get_index_u2_cpcache(), itr->bci()); break;
1585
1586 case Bytecodes::_invokevirtual:
1587 case Bytecodes::_invokespecial: do_method(false, false, itr->get_index_u2_cpcache(), itr->bci()); break;
1588 case Bytecodes::_invokestatic: do_method(true, false, itr->get_index_u2_cpcache(), itr->bci()); break;
1589 case Bytecodes::_invokedynamic: do_method(true, false, itr->get_index_u4(), itr->bci()); break;
1590 case Bytecodes::_invokeinterface: do_method(false, true, itr->get_index_u2_cpcache(), itr->bci()); break;
1591 case Bytecodes::_newarray:
1592 case Bytecodes::_anewarray: pp_new_ref(vCTS, itr->bci()); break;
1593 case Bytecodes::_checkcast: do_checkcast(); break;
1594 case Bytecodes::_arraylength:
1595 case Bytecodes::_instanceof: pp(rCTS, vCTS); break;
1596 case Bytecodes::_monitorenter: do_monitorenter(itr->bci()); break;
1597 case Bytecodes::_monitorexit: do_monitorexit(itr->bci()); break;
1598
1599 case Bytecodes::_athrow: // handled by do_exception_edge() BUT ...
1600 // vlh(apple): do_exception_edge() does not get
1601 // called if method has no exception handlers
1602 if ((!_has_exceptions) && (_monitor_top > 0)) {
1603 _monitor_safe = false;
1604 }
1605 break;
1606
1607 case Bytecodes::_areturn: do_return_monitor_check();
1608 ppop1(refCTS);
1609 break;
1610 case Bytecodes::_ifnull:
1611 case Bytecodes::_ifnonnull: ppop1(refCTS); break;
1612 case Bytecodes::_multianewarray: do_multianewarray(*(itr->bcp()+3), itr->bci()); break;
1613
1614 case Bytecodes::_wide: fatal("Iterator should skip this bytecode"); break;
1615 case Bytecodes::_ret: break;
1616
1617 // Java opcodes
1618 case Bytecodes::_lookupswitch: ppop1(valCTS); break;
1619
1620 default:
1621 tty->print("unexpected opcode: %d\n", itr->code());
1622 ShouldNotReachHere();
1623 break;
1624 }
1625 }
1626
1627 void GenerateOopMap::check_type(CellTypeState expected, CellTypeState actual) {
1628 if (!expected.equal_kind(actual)) {
1629 verify_error("wrong type on stack (found: %c expected: %c)", actual.to_char(), expected.to_char());
1630 }
1631 }
1632
1633 void GenerateOopMap::ppstore(CellTypeState *in, int loc_no) {
1634 while(!(*in).is_bottom()) {
1635 CellTypeState expected =*in++;
1636 CellTypeState actual = pop();
1637 check_type(expected, actual);
1638 assert(loc_no >= 0, "sanity check");
1639 set_var(loc_no++, actual);
1640 }
1641 }
1642
1643 void GenerateOopMap::ppload(CellTypeState *out, int loc_no) {
1644 while(!(*out).is_bottom()) {
1645 CellTypeState out1 = *out++;
1646 CellTypeState vcts = get_var(loc_no);
1647 assert(out1.can_be_reference() || out1.can_be_value(),
1648 "can only load refs. and values.");
1649 if (out1.is_reference()) {
1650 assert(loc_no>=0, "sanity check");
1651 if (!vcts.is_reference()) {
1652 // We were asked to push a reference, but the type of the
1653 // variable can be something else
1654 _conflict = true;
1655 if (vcts.can_be_uninit()) {
1656 // It is a ref-uninit conflict (at least). If there are other
1657 // problems, we'll get them in the next round
1658 add_to_ref_init_set(loc_no);
1659 vcts = out1;
1660 } else {
1661 // It wasn't a ref-uninit conflict. So must be a
1662 // ref-val or ref-pc conflict. Split the variable.
1663 record_refval_conflict(loc_no);
1664 vcts = out1;
1665 }
1666 push(out1); // recover...
1667 } else {
1668 push(vcts); // preserve reference.
1669 }
1670 // Otherwise it is a conflict, but one that verification would
1671 // have caught if illegal. In particular, it can't be a topCTS
1672 // resulting from mergeing two difference pcCTS's since the verifier
1673 // would have rejected any use of such a merge.
1674 } else {
1675 push(out1); // handle val/init conflict
1676 }
1677 loc_no++;
1678 }
1679 }
1680
1681 void GenerateOopMap::ppdupswap(int poplen, const char *out) {
1682 CellTypeState actual[5];
1683 assert(poplen < 5, "this must be less than length of actual vector");
1684
1685 // Pop all arguments.
1686 for (int i = 0; i < poplen; i++) {
1687 actual[i] = pop();
1688 }
1689 // Field _state is uninitialized when calling push.
1690 for (int i = poplen; i < 5; i++) {
1691 actual[i] = CellTypeState::uninit;
1692 }
1693
1694 // put them back
1695 char push_ch = *out++;
1696 while (push_ch != '\0') {
1697 int idx = push_ch - '1';
1698 assert(idx >= 0 && idx < poplen, "wrong arguments");
1699 push(actual[idx]);
1700 push_ch = *out++;
1701 }
1702 }
1703
1704 void GenerateOopMap::ppop1(CellTypeState out) {
1705 CellTypeState actual = pop();
1706 check_type(out, actual);
1707 }
1708
1709 void GenerateOopMap::ppop(CellTypeState *out) {
1710 while (!(*out).is_bottom()) {
1711 ppop1(*out++);
1712 }
1713 }
1714
1715 void GenerateOopMap::ppush1(CellTypeState in) {
1716 assert(in.is_reference() | in.is_value(), "sanity check");
1717 push(in);
1718 }
1719
1720 void GenerateOopMap::ppush(CellTypeState *in) {
1721 while (!(*in).is_bottom()) {
1722 ppush1(*in++);
1723 }
1724 }
1725
1726 void GenerateOopMap::pp(CellTypeState *in, CellTypeState *out) {
1727 ppop(in);
1728 ppush(out);
1729 }
1730
1731 void GenerateOopMap::pp_new_ref(CellTypeState *in, int bci) {
1732 ppop(in);
1733 ppush1(CellTypeState::make_line_ref(bci));
1734 }
1735
1736 void GenerateOopMap::ppop_any(int poplen) {
1737 if (_stack_top >= poplen) {
1738 _stack_top -= poplen;
1739 } else {
1740 verify_error("stack underflow");
1741 }
1742 }
1743
1744 // Replace all occurences of the state 'match' with the state 'replace'
1745 // in our current state vector.
1746 void GenerateOopMap::replace_all_CTS_matches(CellTypeState match,
1747 CellTypeState replace) {
1748 int i;
1749 int len = _max_locals + _stack_top;
1750 bool change = false;
1751
1752 for (i = len - 1; i >= 0; i--) {
1753 if (match.equal(_state[i])) {
1754 _state[i] = replace;
1755 }
1756 }
1757
1758 if (_monitor_top > 0) {
1759 int base = _max_locals + _max_stack;
1760 len = base + _monitor_top;
1761 for (i = len - 1; i >= base; i--) {
1762 if (match.equal(_state[i])) {
1763 _state[i] = replace;
1764 }
1765 }
1766 }
1767 }
1768
1769 void GenerateOopMap::do_checkcast() {
1770 CellTypeState actual = pop();
1771 check_type(refCTS, actual);
1772 push(actual);
1773 }
1774
1775 void GenerateOopMap::do_monitorenter(int bci) {
1776 CellTypeState actual = pop();
1777 if (_monitor_top == bad_monitors) {
1778 return;
1779 }
1780
1781 // Bail out when we get repeated locks on an identical monitor. This case
1782 // isn't too hard to handle and can be made to work if supporting nested
1783 // redundant synchronized statements becomes a priority.
1784 //
1785 // See also "Note" in do_monitorexit(), below.
1786 if (actual.is_lock_reference()) {
1787 _monitor_top = bad_monitors;
1788 _monitor_safe = false;
1789
1790 if (log_is_enabled(Info, monitormismatch)) {
1791 report_monitor_mismatch("nested redundant lock -- bailout...");
1792 }
1793 return;
1794 }
1795
1796 CellTypeState lock = CellTypeState::make_lock_ref(bci);
1797 check_type(refCTS, actual);
1798 if (!actual.is_info_top()) {
1799 replace_all_CTS_matches(actual, lock);
1800 monitor_push(lock);
1801 }
1802 }
1803
1804 void GenerateOopMap::do_monitorexit(int bci) {
1805 CellTypeState actual = pop();
1806 if (_monitor_top == bad_monitors) {
1807 return;
1808 }
1809 check_type(refCTS, actual);
1810 CellTypeState expected = monitor_pop();
1811 if (!actual.is_lock_reference() || !expected.equal(actual)) {
1812 // The monitor we are exiting is not verifiably the one
1813 // on the top of our monitor stack. This causes a monitor
1814 // mismatch.
1815 _monitor_top = bad_monitors;
1816 _monitor_safe = false;
1817
1818 // We need to mark this basic block as changed so that
1819 // this monitorexit will be visited again. We need to
1820 // do this to ensure that we have accounted for the
1821 // possibility that this bytecode will throw an
1822 // exception.
1823 BasicBlock* bb = get_basic_block_containing(bci);
1824 guarantee(bb != NULL, "no basic block for bci");
1825 bb->set_changed(true);
1826 bb->_monitor_top = bad_monitors;
1827
1828 if (log_is_enabled(Info, monitormismatch)) {
1829 report_monitor_mismatch("improper monitor pair");
1830 }
1831 } else {
1832 // This code is a fix for the case where we have repeated
1833 // locking of the same object in straightline code. We clear
1834 // out the lock when it is popped from the monitor stack
1835 // and replace it with an unobtrusive reference value that can
1836 // be locked again.
1837 //
1838 // Note: when generateOopMap is fixed to properly handle repeated,
1839 // nested, redundant locks on the same object, then this
1840 // fix will need to be removed at that time.
1841 replace_all_CTS_matches(actual, CellTypeState::make_line_ref(bci));
1842 }
1843 }
1844
1845 void GenerateOopMap::do_return_monitor_check() {
1846 if (_monitor_top > 0) {
1847 // The monitor stack must be empty when we leave the method
1848 // for the monitors to be properly matched.
1849 _monitor_safe = false;
1850
1851 // Since there are no successors to the *return bytecode, it
1852 // isn't necessary to set _monitor_top to bad_monitors.
1853
1854 if (log_is_enabled(Info, monitormismatch)) {
1855 report_monitor_mismatch("non-empty monitor stack at return");
1856 }
1857 }
1858 }
1859
1860 void GenerateOopMap::do_jsr(int targ_bci) {
1861 push(CellTypeState::make_addr(targ_bci));
1862 }
1863
1864
1865
1866 void GenerateOopMap::do_ldc(int bci) {
1867 Bytecode_loadconstant ldc(method(), bci);
1868 ConstantPool* cp = method()->constants();
1869 constantTag tag = cp->tag_at(ldc.pool_index()); // idx is index in resolved_references
1870 BasicType bt = ldc.result_type();
1871 CellTypeState cts;
1872 if (tag.basic_type() == T_OBJECT) {
1873 assert(!tag.is_string_index() && !tag.is_klass_index(), "Unexpected index tag");
1874 assert(bt == T_OBJECT, "Guard is incorrect");
1875 cts = CellTypeState::make_line_ref(bci);
1876 } else {
1877 assert(bt != T_OBJECT, "Guard is incorrect");
1878 cts = valCTS;
1879 }
1880 ppush1(cts);
1881 }
1882
1883 void GenerateOopMap::do_multianewarray(int dims, int bci) {
1884 assert(dims >= 1, "sanity check");
1885 for(int i = dims -1; i >=0; i--) {
1886 ppop1(valCTS);
1887 }
1888 ppush1(CellTypeState::make_line_ref(bci));
1889 }
1890
1891 void GenerateOopMap::do_astore(int idx) {
1892 CellTypeState r_or_p = pop();
1893 if (!r_or_p.is_address() && !r_or_p.is_reference()) {
1894 // We actually expected ref or pc, but we only report that we expected a ref. It does not
1895 // really matter (at least for now)
1896 verify_error("wrong type on stack (found: %c, expected: {pr})", r_or_p.to_char());
1897 return;
1898 }
1899 set_var(idx, r_or_p);
1900 }
1901
1902 // Copies bottom/zero terminated CTS string from "src" into "dst".
1903 // Does NOT terminate with a bottom. Returns the number of cells copied.
1904 int GenerateOopMap::copy_cts(CellTypeState *dst, CellTypeState *src) {
1905 int idx = 0;
1906 while (!src[idx].is_bottom()) {
1907 dst[idx] = src[idx];
1908 idx++;
1909 }
1910 return idx;
1911 }
1912
1913 void GenerateOopMap::do_field(int is_get, int is_static, int idx, int bci) {
1914 // Dig up signature for field in constant pool
1915 ConstantPool* cp = method()->constants();
1916 int nameAndTypeIdx = cp->name_and_type_ref_index_at(idx);
1917 int signatureIdx = cp->signature_ref_index_at(nameAndTypeIdx);
1918 Symbol* signature = cp->symbol_at(signatureIdx);
1919
1920 // Parse signature (espcially simple for fields)
1921 assert(signature->utf8_length() > 0, "field signatures cannot have zero length");
1922 // The signature is UFT8 encoded, but the first char is always ASCII for signatures.
1923 char sigch = (char)*(signature->base());
1924 CellTypeState temp[4];
1925 CellTypeState *eff = sigchar_to_effect(sigch, bci, temp);
1926
1927 CellTypeState in[4];
1928 CellTypeState *out;
1929 int i = 0;
1930
1931 if (is_get) {
1932 out = eff;
1933 } else {
1934 out = epsilonCTS;
1935 i = copy_cts(in, eff);
1936 }
1937 if (!is_static) in[i++] = CellTypeState::ref;
1938 in[i] = CellTypeState::bottom;
1939 assert(i<=3, "sanity check");
1940 pp(in, out);
1941 }
1942
1943 void GenerateOopMap::do_method(int is_static, int is_interface, int idx, int bci) {
1944 // Dig up signature for field in constant pool
1945 ConstantPool* cp = _method->constants();
1946 Symbol* signature = cp->signature_ref_at(idx);
1947
1948 // Parse method signature
1949 CellTypeState out[4];
1950 CellTypeState in[MAXARGSIZE+1]; // Includes result
1951 ComputeCallStack cse(signature);
1952
1953 // Compute return type
1954 int res_length= cse.compute_for_returntype(out);
1955
1956 // Temporary hack.
1957 if (out[0].equal(CellTypeState::ref) && out[1].equal(CellTypeState::bottom)) {
1958 out[0] = CellTypeState::make_line_ref(bci);
1959 }
1960
1961 assert(res_length<=4, "max value should be vv");
1962
1963 // Compute arguments
1964 int arg_length = cse.compute_for_parameters(is_static != 0, in);
1965 assert(arg_length<=MAXARGSIZE, "too many locals");
1966
1967 // Pop arguments
1968 for (int i = arg_length - 1; i >= 0; i--) ppop1(in[i]);// Do args in reverse order.
1969
1970 // Report results
1971 if (_report_result_for_send == true) {
1972 fill_stackmap_for_opcodes(_itr_send, vars(), stack(), _stack_top);
1973 _report_result_for_send = false;
1974 }
1975
1976 // Push return address
1977 ppush(out);
1978 }
1979
1980 // This is used to parse the signature for fields, since they are very simple...
1981 CellTypeState *GenerateOopMap::sigchar_to_effect(char sigch, int bci, CellTypeState *out) {
1982 // Object and array
1983 if (sigch=='L' || sigch=='[') {
1984 out[0] = CellTypeState::make_line_ref(bci);
1985 out[1] = CellTypeState::bottom;
1986 return out;
1987 }
1988 if (sigch == 'J' || sigch == 'D' ) return vvCTS; // Long and Double
1989 if (sigch == 'V' ) return epsilonCTS; // Void
1990 return vCTS; // Otherwise
1991 }
1992
1993 long GenerateOopMap::_total_byte_count = 0;
1994 elapsedTimer GenerateOopMap::_total_oopmap_time;
1995
1996 // This function assumes "bcs" is at a "ret" instruction and that the vars
1997 // state is valid for that instruction. Furthermore, the ret instruction
1998 // must be the last instruction in "bb" (we store information about the
1999 // "ret" in "bb").
2000 void GenerateOopMap::ret_jump_targets_do(BytecodeStream *bcs, jmpFct_t jmpFct, int varNo, int *data) {
2001 CellTypeState ra = vars()[varNo];
2002 if (!ra.is_good_address()) {
2003 verify_error("ret returns from two jsr subroutines?");
2004 return;
2005 }
2006 int target = ra.get_info();
2007
2008 RetTableEntry* rtEnt = _rt.find_jsrs_for_target(target);
2009 int bci = bcs->bci();
2010 for (int i = 0; i < rtEnt->nof_jsrs(); i++) {
2011 int target_bci = rtEnt->jsrs(i);
2012 // Make sure a jrtRet does not set the changed bit for dead basicblock.
2013 BasicBlock* jsr_bb = get_basic_block_containing(target_bci - 1);
2014 debug_only(BasicBlock* target_bb = &jsr_bb[1];)
2015 assert(target_bb == get_basic_block_at(target_bci), "wrong calc. of successor basicblock");
2016 bool alive = jsr_bb->is_alive();
2017 if (TraceNewOopMapGeneration) {
2018 tty->print("pc = %d, ret -> %d alive: %s\n", bci, target_bci, alive ? "true" : "false");
2019 }
2020 if (alive) jmpFct(this, target_bci, data);
2021 }
2022 }
2023
2024 //
2025 // Debug method
2026 //
2027 char* GenerateOopMap::state_vec_to_string(CellTypeState* vec, int len) {
2028 #ifdef ASSERT
2029 int checklen = MAX3(_max_locals, _max_stack, _max_monitors) + 1;
2030 assert(len < checklen, "state_vec_buf overflow");
2031 #endif
2032 for (int i = 0; i < len; i++) _state_vec_buf[i] = vec[i].to_char();
2033 _state_vec_buf[len] = 0;
2034 return _state_vec_buf;
2035 }
2036
2037 void GenerateOopMap::print_time() {
2038 tty->print_cr ("Accumulated oopmap times:");
2039 tty->print_cr ("---------------------------");
2040 tty->print_cr (" Total : %3.3f sec.", GenerateOopMap::_total_oopmap_time.seconds());
2041 tty->print_cr (" (%3.0f bytecodes per sec) ",
2042 GenerateOopMap::_total_byte_count / GenerateOopMap::_total_oopmap_time.seconds());
2043 }
2044
2045 //
2046 // ============ Main Entry Point ===========
2047 //
2048 GenerateOopMap::GenerateOopMap(const methodHandle& method) {
2049 // We have to initialize all variables here, that can be queried directly
2050 _method = method;
2051 _max_locals=0;
2052 _init_vars = NULL;
2053
2054 #ifndef PRODUCT
2055 // If we are doing a detailed trace, include the regular trace information.
2056 if (TraceNewOopMapGenerationDetailed) {
2057 TraceNewOopMapGeneration = true;
2058 }
2059 #endif
2060 }
2061
2062 void GenerateOopMap::compute_map(TRAPS) {
2063 #ifndef PRODUCT
2064 if (TimeOopMap2) {
2065 method()->print_short_name(tty);
2066 tty->print(" ");
2067 }
2068 if (TimeOopMap) {
2069 _total_byte_count += method()->code_size();
2070 }
2071 #endif
2072 TraceTime t_single("oopmap time", TimeOopMap2);
2073 TraceTime t_all(NULL, &_total_oopmap_time, TimeOopMap);
2074
2075 // Initialize values
2076 _got_error = false;
2077 _conflict = false;
2078 _max_locals = method()->max_locals();
2079 _max_stack = method()->max_stack();
2080 _has_exceptions = (method()->has_exception_handler());
2081 _nof_refval_conflicts = 0;
2082 _init_vars = new GrowableArray<intptr_t>(5); // There are seldom more than 5 init_vars
2083 _report_result = false;
2084 _report_result_for_send = false;
2085 _new_var_map = NULL;
2086 _ret_adr_tos = new GrowableArray<intptr_t>(5); // 5 seems like a good number;
2087 _did_rewriting = false;
2088 _did_relocation = false;
2089
2090 if (TraceNewOopMapGeneration) {
2091 tty->print("Method name: %s\n", method()->name()->as_C_string());
2092 if (Verbose) {
2093 _method->print_codes();
2094 tty->print_cr("Exception table:");
2095 ExceptionTable excps(method());
2096 for(int i = 0; i < excps.length(); i ++) {
2097 tty->print_cr("[%d - %d] -> %d",
2098 excps.start_pc(i), excps.end_pc(i), excps.handler_pc(i));
2099 }
2100 }
2101 }
2102
2103 // if no code - do nothing
2104 // compiler needs info
2105 if (method()->code_size() == 0 || _max_locals + method()->max_stack() == 0) {
2106 fill_stackmap_prolog(0);
2107 fill_stackmap_epilog();
2108 return;
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_and_count_gc_points();
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 if (_got_error) {
2127 THROW_HANDLE(_exception);
2128 }
2129 }
2130
2131 // Error handling methods
2132 // These methods create an exception for the current thread which is thrown
2133 // at the bottom of the call stack, when it returns to compute_map(). The
2134 // _got_error flag controls execution. NOT TODO: The VM exception propagation
2135 // mechanism using TRAPS/CHECKs could be used here instead but it would need
2136 // to be added as a parameter to every function and checked for every call.
2137 // The tons of extra code it would generate didn't seem worth the change.
2138 //
2139 void GenerateOopMap::error_work(const char *format, va_list ap) {
2140 _got_error = true;
2141 char msg_buffer[512];
2142 vsnprintf(msg_buffer, sizeof(msg_buffer), format, ap);
2143 // Append method name
2144 char msg_buffer2[512];
2145 jio_snprintf(msg_buffer2, sizeof(msg_buffer2), "%s in method %s", msg_buffer, method()->name()->as_C_string());
2146 _exception = Exceptions::new_exception(Thread::current(),
2147 vmSymbols::java_lang_LinkageError(), msg_buffer2);
2148 }
2149
2150 void GenerateOopMap::report_error(const char *format, ...) {
2151 va_list ap;
2152 va_start(ap, format);
2153 error_work(format, ap);
2154 }
2155
2156 void GenerateOopMap::verify_error(const char *format, ...) {
2157 // We do not distinguish between different types of errors for verification
2158 // errors. Let the verifier give a better message.
2159 const char *msg = "Illegal class file encountered. Try running with -Xverify:all";
2160 _got_error = true;
2161 // Append method name
2162 char msg_buffer2[512];
2163 jio_snprintf(msg_buffer2, sizeof(msg_buffer2), "%s in method %s", msg,
2164 method()->name()->as_C_string());
2165 _exception = Exceptions::new_exception(Thread::current(),
2166 vmSymbols::java_lang_LinkageError(), msg_buffer2);
2167 }
2168
2169 //
2170 // Report result opcodes
2171 //
2172 void GenerateOopMap::report_result() {
2173
2174 if (TraceNewOopMapGeneration) tty->print_cr("Report result pass");
2175
2176 // We now want to report the result of the parse
2177 _report_result = true;
2178
2179 // Prolog code
2180 fill_stackmap_prolog(_gc_points);
2181
2182 // Mark everything changed, then do one interpretation pass.
2183 for (int i = 0; i<_bb_count; i++) {
2184 if (_basic_blocks[i].is_reachable()) {
2185 _basic_blocks[i].set_changed(true);
2186 interp_bb(&_basic_blocks[i]);
2187 }
2188 }
2189
2190 // Note: Since we are skipping dead-code when we are reporting results, then
2191 // the no. of encountered gc-points might be fewer than the previously number
2192 // we have counted. (dead-code is a pain - it should be removed before we get here)
2193 fill_stackmap_epilog();
2194
2195 // Report initvars
2196 fill_init_vars(_init_vars);
2197
2198 _report_result = false;
2199 }
2200
2201 void GenerateOopMap::result_for_basicblock(int bci) {
2202 if (TraceNewOopMapGeneration) tty->print_cr("Report result pass for basicblock");
2203
2204 // We now want to report the result of the parse
2205 _report_result = true;
2206
2207 // Find basicblock and report results
2208 BasicBlock* bb = get_basic_block_containing(bci);
2209 guarantee(bb != NULL, "no basic block for bci");
2210 assert(bb->is_reachable(), "getting result from unreachable basicblock");
2211 bb->set_changed(true);
2212 interp_bb(bb);
2213 }
2214
2215 //
2216 // Conflict handling code
2217 //
2218
2219 void GenerateOopMap::record_refval_conflict(int varNo) {
2220 assert(varNo>=0 && varNo< _max_locals, "index out of range");
2221
2222 if (TraceOopMapRewrites) {
2223 tty->print("### Conflict detected (local no: %d)\n", varNo);
2224 }
2225
2226 if (!_new_var_map) {
2227 _new_var_map = NEW_RESOURCE_ARRAY(int, _max_locals);
2228 for (int k = 0; k < _max_locals; k++) _new_var_map[k] = k;
2229 }
2230
2231 if ( _new_var_map[varNo] == varNo) {
2232 // Check if max. number of locals has been reached
2233 if (_max_locals + _nof_refval_conflicts >= MAX_LOCAL_VARS) {
2234 report_error("Rewriting exceeded local variable limit");
2235 return;
2236 }
2237 _new_var_map[varNo] = _max_locals + _nof_refval_conflicts;
2238 _nof_refval_conflicts++;
2239 }
2240 }
2241
2242 void GenerateOopMap::rewrite_refval_conflicts()
2243 {
2244 // We can get here two ways: Either a rewrite conflict was detected, or
2245 // an uninitialize reference was detected. In the second case, we do not
2246 // do any rewriting, we just want to recompute the reference set with the
2247 // new information
2248
2249 int nof_conflicts = 0; // Used for debugging only
2250
2251 if ( _nof_refval_conflicts == 0 )
2252 return;
2253
2254 // Check if rewrites are allowed in this parse.
2255 if (!allow_rewrites() && !IgnoreRewrites) {
2256 fatal("Rewriting method not allowed at this stage");
2257 }
2258
2259
2260 // This following flag is to tempoary supress rewrites. The locals that might conflict will
2261 // all be set to contain values. This is UNSAFE - however, until the rewriting has been completely
2262 // tested it is nice to have.
2263 if (IgnoreRewrites) {
2264 if (Verbose) {
2265 tty->print("rewrites suppressed for local no. ");
2266 for (int l = 0; l < _max_locals; l++) {
2267 if (_new_var_map[l] != l) {
2268 tty->print("%d ", l);
2269 vars()[l] = CellTypeState::value;
2270 }
2271 }
2272 tty->cr();
2273 }
2274
2275 // That was that...
2276 _new_var_map = NULL;
2277 _nof_refval_conflicts = 0;
2278 _conflict = false;
2279
2280 return;
2281 }
2282
2283 // Tracing flag
2284 _did_rewriting = true;
2285
2286 if (TraceOopMapRewrites) {
2287 tty->print_cr("ref/value conflict for method %s - bytecodes are getting rewritten", method()->name()->as_C_string());
2288 method()->print();
2289 method()->print_codes();
2290 }
2291
2292 assert(_new_var_map!=NULL, "nothing to rewrite");
2293 assert(_conflict==true, "We should not be here");
2294
2295 compute_ret_adr_at_TOS();
2296 if (!_got_error) {
2297 for (int k = 0; k < _max_locals && !_got_error; k++) {
2298 if (_new_var_map[k] != k) {
2299 if (TraceOopMapRewrites) {
2300 tty->print_cr("Rewriting: %d -> %d", k, _new_var_map[k]);
2301 }
2302 rewrite_refval_conflict(k, _new_var_map[k]);
2303 if (_got_error) return;
2304 nof_conflicts++;
2305 }
2306 }
2307 }
2308
2309 assert(nof_conflicts == _nof_refval_conflicts, "sanity check");
2310
2311 // Adjust the number of locals
2312 method()->set_max_locals(_max_locals+_nof_refval_conflicts);
2313 _max_locals += _nof_refval_conflicts;
2314
2315 // That was that...
2316 _new_var_map = NULL;
2317 _nof_refval_conflicts = 0;
2318 }
2319
2320 void GenerateOopMap::rewrite_refval_conflict(int from, int to) {
2321 bool startOver;
2322 do {
2323 // Make sure that the BytecodeStream is constructed in the loop, since
2324 // during rewriting a new method oop is going to be used, and the next time
2325 // around we want to use that.
2326 BytecodeStream bcs(_method);
2327 startOver = false;
2328
2329 while( !startOver && !_got_error &&
2330 // test bcs in case method changed and it became invalid
2331 bcs.next() >=0) {
2332 startOver = rewrite_refval_conflict_inst(&bcs, from, to);
2333 }
2334 } while (startOver && !_got_error);
2335 }
2336
2337 /* If the current instruction is one that uses local variable "from"
2338 in a ref way, change it to use "to". There's a subtle reason why we
2339 renumber the ref uses and not the non-ref uses: non-ref uses may be
2340 2 slots wide (double, long) which would necessitate keeping track of
2341 whether we should add one or two variables to the method. If the change
2342 affected the width of some instruction, returns "TRUE"; otherwise, returns "FALSE".
2343 Another reason for moving ref's value is for solving (addr, ref) conflicts, which
2344 both uses aload/astore methods.
2345 */
2346 bool GenerateOopMap::rewrite_refval_conflict_inst(BytecodeStream *itr, int from, int to) {
2347 Bytecodes::Code bc = itr->code();
2348 int index;
2349 int bci = itr->bci();
2350
2351 if (is_aload(itr, &index) && index == from) {
2352 if (TraceOopMapRewrites) {
2353 tty->print_cr("Rewriting aload at bci: %d", bci);
2354 }
2355 return rewrite_load_or_store(itr, Bytecodes::_aload, Bytecodes::_aload_0, to);
2356 }
2357
2358 if (is_astore(itr, &index) && index == from) {
2359 if (!stack_top_holds_ret_addr(bci)) {
2360 if (TraceOopMapRewrites) {
2361 tty->print_cr("Rewriting astore at bci: %d", bci);
2362 }
2363 return rewrite_load_or_store(itr, Bytecodes::_astore, Bytecodes::_astore_0, to);
2364 } else {
2365 if (TraceOopMapRewrites) {
2366 tty->print_cr("Supress rewriting of astore at bci: %d", bci);
2367 }
2368 }
2369 }
2370
2371 return false;
2372 }
2373
2374 // The argument to this method is:
2375 // bc : Current bytecode
2376 // bcN : either _aload or _astore
2377 // bc0 : either _aload_0 or _astore_0
2378 bool GenerateOopMap::rewrite_load_or_store(BytecodeStream *bcs, Bytecodes::Code bcN, Bytecodes::Code bc0, unsigned int varNo) {
2379 assert(bcN == Bytecodes::_astore || bcN == Bytecodes::_aload, "wrong argument (bcN)");
2380 assert(bc0 == Bytecodes::_astore_0 || bc0 == Bytecodes::_aload_0, "wrong argument (bc0)");
2381 int ilen = Bytecodes::length_at(_method(), bcs->bcp());
2382 int newIlen;
2383
2384 if (ilen == 4) {
2385 // Original instruction was wide; keep it wide for simplicity
2386 newIlen = 4;
2387 } else if (varNo < 4)
2388 newIlen = 1;
2389 else if (varNo >= 256)
2390 newIlen = 4;
2391 else
2392 newIlen = 2;
2393
2394 // If we need to relocate in order to patch the byte, we
2395 // do the patching in a temp. buffer, that is passed to the reloc.
2396 // The patching of the bytecode stream is then done by the Relocator.
2397 // This is neccesary, since relocating the instruction at a certain bci, might
2398 // also relocate that instruction, e.g., if a _goto before it gets widen to a _goto_w.
2399 // Hence, we do not know which bci to patch after relocation.
2400
2401 assert(newIlen <= 4, "sanity check");
2402 u_char inst_buffer[4]; // Max. instruction size is 4.
2403 address bcp;
2404
2405 if (newIlen != ilen) {
2406 // Relocation needed do patching in temp. buffer
2407 bcp = (address)inst_buffer;
2408 } else {
2409 bcp = _method->bcp_from(bcs->bci());
2410 }
2411
2412 // Patch either directly in Method* or in temp. buffer
2413 if (newIlen == 1) {
2414 assert(varNo < 4, "varNo too large");
2415 *bcp = bc0 + varNo;
2416 } else if (newIlen == 2) {
2417 assert(varNo < 256, "2-byte index needed!");
2418 *(bcp + 0) = bcN;
2419 *(bcp + 1) = varNo;
2420 } else {
2421 assert(newIlen == 4, "Wrong instruction length");
2422 *(bcp + 0) = Bytecodes::_wide;
2423 *(bcp + 1) = bcN;
2424 Bytes::put_Java_u2(bcp+2, varNo);
2425 }
2426
2427 if (newIlen != ilen) {
2428 expand_current_instr(bcs->bci(), ilen, newIlen, inst_buffer);
2429 }
2430
2431
2432 return (newIlen != ilen);
2433 }
2434
2435 class RelocCallback : public RelocatorListener {
2436 private:
2437 GenerateOopMap* _gom;
2438 public:
2439 RelocCallback(GenerateOopMap* gom) { _gom = gom; };
2440
2441 // Callback method
2442 virtual void relocated(int bci, int delta, int new_code_length) {
2443 _gom->update_basic_blocks (bci, delta, new_code_length);
2444 _gom->update_ret_adr_at_TOS(bci, delta);
2445 _gom->_rt.update_ret_table (bci, delta);
2446 }
2447 };
2448
2449 // Returns true if expanding was succesful. Otherwise, reports an error and
2450 // returns false.
2451 void GenerateOopMap::expand_current_instr(int bci, int ilen, int newIlen, u_char inst_buffer[]) {
2452 Thread *THREAD = Thread::current(); // Could really have TRAPS argument.
2453 RelocCallback rcb(this);
2454 Relocator rc(_method, &rcb);
2455 methodHandle m= rc.insert_space_at(bci, newIlen, inst_buffer, THREAD);
2456 if (m.is_null() || HAS_PENDING_EXCEPTION) {
2457 report_error("could not rewrite method - exception occurred or bytecode buffer overflow");
2458 return;
2459 }
2460
2461 // Relocator returns a new method oop.
2462 _did_relocation = true;
2463 _method = m;
2464 }
2465
2466
2467 bool GenerateOopMap::is_astore(BytecodeStream *itr, int *index) {
2468 Bytecodes::Code bc = itr->code();
2469 switch(bc) {
2470 case Bytecodes::_astore_0:
2471 case Bytecodes::_astore_1:
2472 case Bytecodes::_astore_2:
2473 case Bytecodes::_astore_3:
2474 *index = bc - Bytecodes::_astore_0;
2475 return true;
2476 case Bytecodes::_astore:
2477 *index = itr->get_index();
2478 return true;
2479 }
2480 return false;
2481 }
2482
2483 bool GenerateOopMap::is_aload(BytecodeStream *itr, int *index) {
2484 Bytecodes::Code bc = itr->code();
2485 switch(bc) {
2486 case Bytecodes::_aload_0:
2487 case Bytecodes::_aload_1:
2488 case Bytecodes::_aload_2:
2489 case Bytecodes::_aload_3:
2490 *index = bc - Bytecodes::_aload_0;
2491 return true;
2492
2493 case Bytecodes::_aload:
2494 *index = itr->get_index();
2495 return true;
2496 }
2497 return false;
2498 }
2499
2500
2501 // Return true iff the top of the operand stack holds a return address at
2502 // the current instruction
2503 bool GenerateOopMap::stack_top_holds_ret_addr(int bci) {
2504 for(int i = 0; i < _ret_adr_tos->length(); i++) {
2505 if (_ret_adr_tos->at(i) == bci)
2506 return true;
2507 }
2508
2509 return false;
2510 }
2511
2512 void GenerateOopMap::compute_ret_adr_at_TOS() {
2513 assert(_ret_adr_tos != NULL, "must be initialized");
2514 _ret_adr_tos->clear();
2515
2516 for (int i = 0; i < bb_count(); i++) {
2517 BasicBlock* bb = &_basic_blocks[i];
2518
2519 // Make sure to only check basicblocks that are reachable
2520 if (bb->is_reachable()) {
2521
2522 // For each Basic block we check all instructions
2523 BytecodeStream bcs(_method);
2524 bcs.set_interval(bb->_bci, next_bb_start_pc(bb));
2525
2526 restore_state(bb);
2527
2528 while (bcs.next()>=0 && !_got_error) {
2529 // TDT: should this be is_good_address() ?
2530 if (_stack_top > 0 && stack()[_stack_top-1].is_address()) {
2531 _ret_adr_tos->append(bcs.bci());
2532 if (TraceNewOopMapGeneration) {
2533 tty->print_cr("Ret_adr TOS at bci: %d", bcs.bci());
2534 }
2535 }
2536 interp1(&bcs);
2537 }
2538 }
2539 }
2540 }
2541
2542 void GenerateOopMap::update_ret_adr_at_TOS(int bci, int delta) {
2543 for(int i = 0; i < _ret_adr_tos->length(); i++) {
2544 int v = _ret_adr_tos->at(i);
2545 if (v > bci) _ret_adr_tos->at_put(i, v + delta);
2546 }
2547 }
2548
2549 // ===================================================================
2550
2551 #ifndef PRODUCT
2552 int ResolveOopMapConflicts::_nof_invocations = 0;
2553 int ResolveOopMapConflicts::_nof_rewrites = 0;
2554 int ResolveOopMapConflicts::_nof_relocations = 0;
2555 #endif
2556
2557 methodHandle ResolveOopMapConflicts::do_potential_rewrite(TRAPS) {
2558 compute_map(CHECK_(methodHandle()));
2559
2560 #ifndef PRODUCT
2561 // Tracking and statistics
2562 if (PrintRewrites) {
2563 _nof_invocations++;
2564 if (did_rewriting()) {
2565 _nof_rewrites++;
2566 if (did_relocation()) _nof_relocations++;
2567 tty->print("Method was rewritten %s: ", (did_relocation()) ? "and relocated" : "");
2568 method()->print_value(); tty->cr();
2569 tty->print_cr("Cand.: %d rewrts: %d (%d%%) reloc.: %d (%d%%)",
2570 _nof_invocations,
2571 _nof_rewrites, (_nof_rewrites * 100) / _nof_invocations,
2572 _nof_relocations, (_nof_relocations * 100) / _nof_invocations);
2573 }
2574 }
2575 #endif
2576 return methodHandle(THREAD, method());
2577 }