1 /*
2 * Copyright (c) 1997, 2016, 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 #include "prims/methodHandles.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.clear();
385 _bb_hdr_bits.resize(method()->code_size());
386 }
387
388 void GenerateOopMap::bb_mark_fct(GenerateOopMap *c, int bci, int *data) {
389 assert(bci>= 0 && bci < c->method()->code_size(), "index out of bounds");
390 if (c->is_bb_header(bci))
391 return;
392
393 if (TraceNewOopMapGeneration) {
394 tty->print_cr("Basicblock#%d begins at: %d", c->_bb_count, bci);
395 }
396 c->set_bbmark_bit(bci);
397 c->_bb_count++;
398 }
399
400
401 void GenerateOopMap::mark_bbheaders_and_count_gc_points() {
402 initialize_bb();
403
404 bool fellThrough = false; // False to get first BB marked.
405
406 // First mark all exception handlers as start of a basic-block
407 ExceptionTable excps(method());
408 for(int i = 0; i < excps.length(); i ++) {
409 bb_mark_fct(this, excps.handler_pc(i), NULL);
410 }
411
412 // Then iterate through the code
413 BytecodeStream bcs(_method);
414 Bytecodes::Code bytecode;
415
416 while( (bytecode = bcs.next()) >= 0) {
417 int bci = bcs.bci();
418
419 if (!fellThrough)
420 bb_mark_fct(this, bci, NULL);
421
422 fellThrough = jump_targets_do(&bcs, &GenerateOopMap::bb_mark_fct, NULL);
423
424 /* We will also mark successors of jsr's as basic block headers. */
425 switch (bytecode) {
426 case Bytecodes::_jsr:
427 assert(!fellThrough, "should not happen");
428 bb_mark_fct(this, bci + Bytecodes::length_for(bytecode), NULL);
429 break;
430 case Bytecodes::_jsr_w:
431 assert(!fellThrough, "should not happen");
432 bb_mark_fct(this, bci + Bytecodes::length_for(bytecode), NULL);
433 break;
434 }
435
436 if (possible_gc_point(&bcs))
437 _gc_points++;
438 }
439 }
440
441 void GenerateOopMap::reachable_basicblock(GenerateOopMap *c, int bci, int *data) {
442 assert(bci>= 0 && bci < c->method()->code_size(), "index out of bounds");
443 BasicBlock* bb = c->get_basic_block_at(bci);
444 if (bb->is_dead()) {
445 bb->mark_as_alive();
446 *data = 1; // Mark basicblock as changed
447 }
448 }
449
450
451 void GenerateOopMap::mark_reachable_code() {
452 int change = 1; // int to get function pointers to work
453
454 // Mark entry basic block as alive and all exception handlers
455 _basic_blocks[0].mark_as_alive();
456 ExceptionTable excps(method());
457 for(int i = 0; i < excps.length(); i++) {
458 BasicBlock *bb = get_basic_block_at(excps.handler_pc(i));
459 // If block is not already alive (due to multiple exception handlers to same bb), then
460 // make it alive
461 if (bb->is_dead()) bb->mark_as_alive();
462 }
463
464 BytecodeStream bcs(_method);
465
466 // Iterate through all basic blocks until we reach a fixpoint
467 while (change) {
468 change = 0;
469
470 for (int i = 0; i < _bb_count; i++) {
471 BasicBlock *bb = &_basic_blocks[i];
472 if (bb->is_alive()) {
473 // Position bytecodestream at last bytecode in basicblock
474 bcs.set_start(bb->_end_bci);
475 bcs.next();
476 Bytecodes::Code bytecode = bcs.code();
477 int bci = bcs.bci();
478 assert(bci == bb->_end_bci, "wrong bci");
479
480 bool fell_through = jump_targets_do(&bcs, &GenerateOopMap::reachable_basicblock, &change);
481
482 // We will also mark successors of jsr's as alive.
483 switch (bytecode) {
484 case Bytecodes::_jsr:
485 case Bytecodes::_jsr_w:
486 assert(!fell_through, "should not happen");
487 reachable_basicblock(this, bci + Bytecodes::length_for(bytecode), &change);
488 break;
489 }
490 if (fell_through) {
491 // Mark successor as alive
492 if (bb[1].is_dead()) {
493 bb[1].mark_as_alive();
494 change = 1;
495 }
496 }
497 }
498 }
499 }
500 }
501
502 /* If the current instruction in "c" has no effect on control flow,
503 returns "true". Otherwise, calls "jmpFct" one or more times, with
504 "c", an appropriate "pcDelta", and "data" as arguments, then
505 returns "false". There is one exception: if the current
506 instruction is a "ret", returns "false" without calling "jmpFct".
507 Arrangements for tracking the control flow of a "ret" must be made
508 externally. */
509 bool GenerateOopMap::jump_targets_do(BytecodeStream *bcs, jmpFct_t jmpFct, int *data) {
510 int bci = bcs->bci();
511
512 switch (bcs->code()) {
513 case Bytecodes::_ifeq:
514 case Bytecodes::_ifne:
515 case Bytecodes::_iflt:
516 case Bytecodes::_ifge:
517 case Bytecodes::_ifgt:
518 case Bytecodes::_ifle:
519 case Bytecodes::_if_icmpeq:
520 case Bytecodes::_if_icmpne:
521 case Bytecodes::_if_icmplt:
522 case Bytecodes::_if_icmpge:
523 case Bytecodes::_if_icmpgt:
524 case Bytecodes::_if_icmple:
525 case Bytecodes::_if_acmpeq:
526 case Bytecodes::_if_acmpne:
527 case Bytecodes::_ifnull:
528 case Bytecodes::_ifnonnull:
529 (*jmpFct)(this, bcs->dest(), data);
530 (*jmpFct)(this, bci + 3, data);
531 break;
532
533 case Bytecodes::_goto:
534 (*jmpFct)(this, bcs->dest(), data);
535 break;
536 case Bytecodes::_goto_w:
537 (*jmpFct)(this, bcs->dest_w(), data);
538 break;
539 case Bytecodes::_tableswitch:
540 { Bytecode_tableswitch tableswitch(method(), bcs->bcp());
541 int len = tableswitch.length();
542
543 (*jmpFct)(this, bci + tableswitch.default_offset(), data); /* Default. jump address */
544 while (--len >= 0) {
545 (*jmpFct)(this, bci + tableswitch.dest_offset_at(len), data);
546 }
547 break;
548 }
549
550 case Bytecodes::_lookupswitch:
551 { Bytecode_lookupswitch lookupswitch(method(), bcs->bcp());
552 int npairs = lookupswitch.number_of_pairs();
553 (*jmpFct)(this, bci + lookupswitch.default_offset(), data); /* Default. */
554 while(--npairs >= 0) {
555 LookupswitchPair pair = lookupswitch.pair_at(npairs);
556 (*jmpFct)(this, bci + pair.offset(), data);
557 }
558 break;
559 }
560 case Bytecodes::_jsr:
561 assert(bcs->is_wide()==false, "sanity check");
562 (*jmpFct)(this, bcs->dest(), data);
563
564
565
566 break;
567 case Bytecodes::_jsr_w:
568 (*jmpFct)(this, bcs->dest_w(), data);
569 break;
570 case Bytecodes::_wide:
571 ShouldNotReachHere();
572 return true;
573 break;
574 case Bytecodes::_athrow:
575 case Bytecodes::_ireturn:
576 case Bytecodes::_lreturn:
577 case Bytecodes::_freturn:
578 case Bytecodes::_dreturn:
579 case Bytecodes::_areturn:
580 case Bytecodes::_return:
581 case Bytecodes::_ret:
582 break;
583 default:
584 return true;
585 }
586 return false;
587 }
588
589 /* Requires "pc" to be the head of a basic block; returns that basic
590 block. */
591 BasicBlock *GenerateOopMap::get_basic_block_at(int bci) const {
592 BasicBlock* bb = get_basic_block_containing(bci);
593 assert(bb->_bci == bci, "should have found BB");
594 return bb;
595 }
596
597 // Requires "pc" to be the start of an instruction; returns the basic
598 // block containing that instruction. */
599 BasicBlock *GenerateOopMap::get_basic_block_containing(int bci) const {
600 BasicBlock *bbs = _basic_blocks;
601 int lo = 0, hi = _bb_count - 1;
602
603 while (lo <= hi) {
604 int m = (lo + hi) / 2;
605 int mbci = bbs[m]._bci;
606 int nbci;
607
608 if ( m == _bb_count-1) {
609 assert( bci >= mbci && bci < method()->code_size(), "sanity check failed");
610 return bbs+m;
611 } else {
612 nbci = bbs[m+1]._bci;
613 }
614
615 if ( mbci <= bci && bci < nbci) {
616 return bbs+m;
617 } else if (mbci < bci) {
618 lo = m + 1;
619 } else {
620 assert(mbci > bci, "sanity check");
621 hi = m - 1;
622 }
623 }
624
625 fatal("should have found BB");
626 return NULL;
627 }
628
629 void GenerateOopMap::restore_state(BasicBlock *bb)
630 {
631 memcpy(_state, bb->_state, _state_len*sizeof(CellTypeState));
632 _stack_top = bb->_stack_top;
633 _monitor_top = bb->_monitor_top;
634 }
635
636 int GenerateOopMap::next_bb_start_pc(BasicBlock *bb) {
637 int bbNum = bb - _basic_blocks + 1;
638 if (bbNum == _bb_count)
639 return method()->code_size();
640
641 return _basic_blocks[bbNum]._bci;
642 }
643
644 //
645 // CellType handling methods
646 //
647
648 // Allocate memory and throw LinkageError if failure.
649 #define ALLOC_RESOURCE_ARRAY(var, type, count) \
650 var = NEW_RESOURCE_ARRAY_RETURN_NULL(type, count); \
651 if (var == NULL) { \
652 report_error("Cannot reserve enough memory to analyze this method"); \
653 return; \
654 }
655
656
657 void GenerateOopMap::init_state() {
658 _state_len = _max_locals + _max_stack + _max_monitors;
659 ALLOC_RESOURCE_ARRAY(_state, CellTypeState, _state_len);
660 memset(_state, 0, _state_len * sizeof(CellTypeState));
661 int count = MAX3(_max_locals, _max_stack, _max_monitors) + 1/*for null terminator char */;
662 ALLOC_RESOURCE_ARRAY(_state_vec_buf, char, count);
663 }
664
665 void GenerateOopMap::make_context_uninitialized() {
666 CellTypeState* vs = vars();
667
668 for (int i = 0; i < _max_locals; i++)
669 vs[i] = CellTypeState::uninit;
670
671 _stack_top = 0;
672 _monitor_top = 0;
673 }
674
675 int GenerateOopMap::methodsig_to_effect(Symbol* signature, bool is_static, CellTypeState* effect) {
676 ComputeEntryStack ces(signature);
677 return ces.compute_for_parameters(is_static, effect);
678 }
679
680 // Return result of merging cts1 and cts2.
681 CellTypeState CellTypeState::merge(CellTypeState cts, int slot) const {
682 CellTypeState result;
683
684 assert(!is_bottom() && !cts.is_bottom(),
685 "merge of bottom values is handled elsewhere");
686
687 result._state = _state | cts._state;
688
689 // If the top bit is set, we don't need to do any more work.
690 if (!result.is_info_top()) {
691 assert((result.can_be_address() || result.can_be_reference()),
692 "only addresses and references have non-top info");
693
694 if (!equal(cts)) {
695 // The two values being merged are different. Raise to top.
696 if (result.is_reference()) {
697 result = CellTypeState::make_slot_ref(slot);
698 } else {
699 result._state |= info_conflict;
700 }
701 }
702 }
703 assert(result.is_valid_state(), "checking that CTS merge maintains legal state");
704
705 return result;
706 }
707
708 // Merge the variable state for locals and stack from cts into bbts.
709 bool GenerateOopMap::merge_local_state_vectors(CellTypeState* cts,
710 CellTypeState* bbts) {
711 int i;
712 int len = _max_locals + _stack_top;
713 bool change = false;
714
715 for (i = len - 1; i >= 0; i--) {
716 CellTypeState v = cts[i].merge(bbts[i], i);
717 change = change || !v.equal(bbts[i]);
718 bbts[i] = v;
719 }
720
721 return change;
722 }
723
724 // Merge the monitor stack state from cts into bbts.
725 bool GenerateOopMap::merge_monitor_state_vectors(CellTypeState* cts,
726 CellTypeState* bbts) {
727 bool change = false;
728 if (_max_monitors > 0 && _monitor_top != bad_monitors) {
729 // If there are no monitors in the program, or there has been
730 // a monitor matching error before this point in the program,
731 // then we do not merge in the monitor state.
732
733 int base = _max_locals + _max_stack;
734 int len = base + _monitor_top;
735 for (int i = len - 1; i >= base; i--) {
736 CellTypeState v = cts[i].merge(bbts[i], i);
737
738 // Can we prove that, when there has been a change, it will already
739 // have been detected at this point? That would make this equal
740 // check here unnecessary.
741 change = change || !v.equal(bbts[i]);
742 bbts[i] = v;
743 }
744 }
745
746 return change;
747 }
748
749 void GenerateOopMap::copy_state(CellTypeState *dst, CellTypeState *src) {
750 int len = _max_locals + _stack_top;
751 for (int i = 0; i < len; i++) {
752 if (src[i].is_nonlock_reference()) {
753 dst[i] = CellTypeState::make_slot_ref(i);
754 } else {
755 dst[i] = src[i];
756 }
757 }
758 if (_max_monitors > 0 && _monitor_top != bad_monitors) {
759 int base = _max_locals + _max_stack;
760 len = base + _monitor_top;
761 for (int i = base; i < len; i++) {
762 dst[i] = src[i];
763 }
764 }
765 }
766
767
768 // Merge the states for the current block and the next. As long as a
769 // block is reachable the locals and stack must be merged. If the
770 // stack heights don't match then this is a verification error and
771 // it's impossible to interpret the code. Simultaneously monitor
772 // states are being check to see if they nest statically. If monitor
773 // depths match up then their states are merged. Otherwise the
774 // mismatch is simply recorded and interpretation continues since
775 // monitor matching is purely informational and doesn't say anything
776 // about the correctness of the code.
777 void GenerateOopMap::merge_state_into_bb(BasicBlock *bb) {
778 guarantee(bb != NULL, "null basicblock");
779 assert(bb->is_alive(), "merging state into a dead basicblock");
780
781 if (_stack_top == bb->_stack_top) {
782 // always merge local state even if monitors don't match.
783 if (merge_local_state_vectors(_state, bb->_state)) {
784 bb->set_changed(true);
785 }
786 if (_monitor_top == bb->_monitor_top) {
787 // monitors still match so continue merging monitor states.
788 if (merge_monitor_state_vectors(_state, bb->_state)) {
789 bb->set_changed(true);
790 }
791 } else {
792 if (log_is_enabled(Info, monitormismatch)) {
793 report_monitor_mismatch("monitor stack height merge conflict");
794 }
795 // When the monitor stacks are not matched, we set _monitor_top to
796 // bad_monitors. This signals that, from here on, the monitor stack cannot
797 // be trusted. In particular, monitorexit bytecodes may throw
798 // exceptions. We mark this block as changed so that the change
799 // propagates properly.
800 bb->_monitor_top = bad_monitors;
801 bb->set_changed(true);
802 _monitor_safe = false;
803 }
804 } else if (!bb->is_reachable()) {
805 // First time we look at this BB
806 copy_state(bb->_state, _state);
807 bb->_stack_top = _stack_top;
808 bb->_monitor_top = _monitor_top;
809 bb->set_changed(true);
810 } else {
811 verify_error("stack height conflict: %d vs. %d", _stack_top, bb->_stack_top);
812 }
813 }
814
815 void GenerateOopMap::merge_state(GenerateOopMap *gom, int bci, int* data) {
816 gom->merge_state_into_bb(gom->get_basic_block_at(bci));
817 }
818
819 void GenerateOopMap::set_var(int localNo, CellTypeState cts) {
820 assert(cts.is_reference() || cts.is_value() || cts.is_address(),
821 "wrong celltypestate");
822 if (localNo < 0 || localNo > _max_locals) {
823 verify_error("variable write error: r%d", localNo);
824 return;
825 }
826 vars()[localNo] = cts;
827 }
828
829 CellTypeState GenerateOopMap::get_var(int localNo) {
830 assert(localNo < _max_locals + _nof_refval_conflicts, "variable read error");
831 if (localNo < 0 || localNo > _max_locals) {
832 verify_error("variable read error: r%d", localNo);
833 return valCTS; // just to pick something;
834 }
835 return vars()[localNo];
836 }
837
838 CellTypeState GenerateOopMap::pop() {
839 if ( _stack_top <= 0) {
840 verify_error("stack underflow");
841 return valCTS; // just to pick something
842 }
843 return stack()[--_stack_top];
844 }
845
846 void GenerateOopMap::push(CellTypeState cts) {
847 if ( _stack_top >= _max_stack) {
848 verify_error("stack overflow");
849 return;
850 }
851 stack()[_stack_top++] = cts;
852 }
853
854 CellTypeState GenerateOopMap::monitor_pop() {
855 assert(_monitor_top != bad_monitors, "monitor_pop called on error monitor stack");
856 if (_monitor_top == 0) {
857 // We have detected a pop of an empty monitor stack.
858 _monitor_safe = false;
859 _monitor_top = bad_monitors;
860
861 if (log_is_enabled(Info, monitormismatch)) {
862 report_monitor_mismatch("monitor stack underflow");
863 }
864 return CellTypeState::ref; // just to keep the analysis going.
865 }
866 return monitors()[--_monitor_top];
867 }
868
869 void GenerateOopMap::monitor_push(CellTypeState cts) {
870 assert(_monitor_top != bad_monitors, "monitor_push called on error monitor stack");
871 if (_monitor_top >= _max_monitors) {
872 // Some monitorenter is being executed more than once.
873 // This means that the monitor stack cannot be simulated.
874 _monitor_safe = false;
875 _monitor_top = bad_monitors;
876
877 if (log_is_enabled(Info, monitormismatch)) {
878 report_monitor_mismatch("monitor stack overflow");
879 }
880 return;
881 }
882 monitors()[_monitor_top++] = cts;
883 }
884
885 //
886 // Interpretation handling methods
887 //
888
889 void GenerateOopMap::do_interpretation()
890 {
891 // "i" is just for debugging, so we can detect cases where this loop is
892 // iterated more than once.
893 int i = 0;
894 do {
895 #ifndef PRODUCT
896 if (TraceNewOopMapGeneration) {
897 tty->print("\n\nIteration #%d of do_interpretation loop, method:\n", i);
898 method()->print_name(tty);
899 tty->print("\n\n");
900 }
901 #endif
902 _conflict = false;
903 _monitor_safe = true;
904 // init_state is now called from init_basic_blocks. The length of a
905 // state vector cannot be determined until we have made a pass through
906 // the bytecodes counting the possible monitor entries.
907 if (!_got_error) init_basic_blocks();
908 if (!_got_error) setup_method_entry_state();
909 if (!_got_error) interp_all();
910 if (!_got_error) rewrite_refval_conflicts();
911 i++;
912 } while (_conflict && !_got_error);
913 }
914
915 void GenerateOopMap::init_basic_blocks() {
916 // Note: Could consider reserving only the needed space for each BB's state
917 // (entry stack may not be of maximal height for every basic block).
918 // But cumbersome since we don't know the stack heights yet. (Nor the
919 // monitor stack heights...)
920
921 ALLOC_RESOURCE_ARRAY(_basic_blocks, BasicBlock, _bb_count);
922
923 // Make a pass through the bytecodes. Count the number of monitorenters.
924 // This can be used an upper bound on the monitor stack depth in programs
925 // which obey stack discipline with their monitor usage. Initialize the
926 // known information about basic blocks.
927 BytecodeStream j(_method);
928 Bytecodes::Code bytecode;
929
930 int bbNo = 0;
931 int monitor_count = 0;
932 int prev_bci = -1;
933 while( (bytecode = j.next()) >= 0) {
934 if (j.code() == Bytecodes::_monitorenter) {
935 monitor_count++;
936 }
937
938 int bci = j.bci();
939 if (is_bb_header(bci)) {
940 // Initialize the basicblock structure
941 BasicBlock *bb = _basic_blocks + bbNo;
942 bb->_bci = bci;
943 bb->_max_locals = _max_locals;
944 bb->_max_stack = _max_stack;
945 bb->set_changed(false);
946 bb->_stack_top = BasicBlock::_dead_basic_block; // Initialize all basicblocks are dead.
947 bb->_monitor_top = bad_monitors;
948
949 if (bbNo > 0) {
950 _basic_blocks[bbNo - 1]._end_bci = prev_bci;
951 }
952
953 bbNo++;
954 }
955 // Remember prevous bci.
956 prev_bci = bci;
957 }
958 // Set
959 _basic_blocks[bbNo-1]._end_bci = prev_bci;
960
961
962 // Check that the correct number of basicblocks was found
963 if (bbNo !=_bb_count) {
964 if (bbNo < _bb_count) {
965 verify_error("jump into the middle of instruction?");
966 return;
967 } else {
968 verify_error("extra basic blocks - should not happen?");
969 return;
970 }
971 }
972
973 _max_monitors = monitor_count;
974
975 // Now that we have a bound on the depth of the monitor stack, we can
976 // initialize the CellTypeState-related information.
977 init_state();
978
979 // We allocate space for all state-vectors for all basicblocks in one huge
980 // chunk. Then in the next part of the code, we set a pointer in each
981 // _basic_block that points to each piece.
982
983 // The product of bbNo and _state_len can get large if there are lots of
984 // basic blocks and stack/locals/monitors. Need to check to make sure
985 // we don't overflow the capacity of a pointer.
986 if ((unsigned)bbNo > UINTPTR_MAX / sizeof(CellTypeState) / _state_len) {
987 report_error("The amount of memory required to analyze this method "
988 "exceeds addressable range");
989 return;
990 }
991
992 CellTypeState *basicBlockState;
993 ALLOC_RESOURCE_ARRAY(basicBlockState, CellTypeState, bbNo * _state_len);
994 memset(basicBlockState, 0, bbNo * _state_len * sizeof(CellTypeState));
995
996 // Make a pass over the basicblocks and assign their state vectors.
997 for (int blockNum=0; blockNum < bbNo; blockNum++) {
998 BasicBlock *bb = _basic_blocks + blockNum;
999 bb->_state = basicBlockState + blockNum * _state_len;
1000
1001 #ifdef ASSERT
1002 if (blockNum + 1 < bbNo) {
1003 address bcp = _method->bcp_from(bb->_end_bci);
1004 int bc_len = Bytecodes::java_length_at(_method(), bcp);
1005 assert(bb->_end_bci + bc_len == bb[1]._bci, "unmatched bci info in basicblock");
1006 }
1007 #endif
1008 }
1009 #ifdef ASSERT
1010 { BasicBlock *bb = &_basic_blocks[bbNo-1];
1011 address bcp = _method->bcp_from(bb->_end_bci);
1012 int bc_len = Bytecodes::java_length_at(_method(), bcp);
1013 assert(bb->_end_bci + bc_len == _method->code_size(), "wrong end bci");
1014 }
1015 #endif
1016
1017 // Mark all alive blocks
1018 mark_reachable_code();
1019 }
1020
1021 void GenerateOopMap::setup_method_entry_state() {
1022
1023 // Initialize all locals to 'uninit' and set stack-height to 0
1024 make_context_uninitialized();
1025
1026 // Initialize CellState type of arguments
1027 methodsig_to_effect(method()->signature(), method()->is_static(), vars());
1028
1029 // If some references must be pre-assigned to null, then set that up
1030 initialize_vars();
1031
1032 // This is the start state
1033 merge_state_into_bb(&_basic_blocks[0]);
1034
1035 assert(_basic_blocks[0].changed(), "we are not getting off the ground");
1036 }
1037
1038 // The instruction at bci is changing size by "delta". Update the basic blocks.
1039 void GenerateOopMap::update_basic_blocks(int bci, int delta,
1040 int new_method_size) {
1041 assert(new_method_size >= method()->code_size() + delta,
1042 "new method size is too small");
1043
1044 BitMap::bm_word_t* new_bb_hdr_bits =
1045 NEW_RESOURCE_ARRAY(BitMap::bm_word_t,
1046 BitMap::word_align_up(new_method_size));
1047 _bb_hdr_bits.set_map(new_bb_hdr_bits);
1048 _bb_hdr_bits.set_size(new_method_size);
1049 _bb_hdr_bits.clear();
1050
1051
1052 for(int k = 0; k < _bb_count; k++) {
1053 if (_basic_blocks[k]._bci > bci) {
1054 _basic_blocks[k]._bci += delta;
1055 _basic_blocks[k]._end_bci += delta;
1056 }
1057 _bb_hdr_bits.at_put(_basic_blocks[k]._bci, true);
1058 }
1059 }
1060
1061 //
1062 // Initvars handling
1063 //
1064
1065 void GenerateOopMap::initialize_vars() {
1066 for (int k = 0; k < _init_vars->length(); k++)
1067 _state[_init_vars->at(k)] = CellTypeState::make_slot_ref(k);
1068 }
1069
1070 void GenerateOopMap::add_to_ref_init_set(int localNo) {
1071
1072 if (TraceNewOopMapGeneration)
1073 tty->print_cr("Added init vars: %d", localNo);
1074
1075 // Is it already in the set?
1076 if (_init_vars->contains(localNo) )
1077 return;
1078
1079 _init_vars->append(localNo);
1080 }
1081
1082 //
1083 // Interpreration code
1084 //
1085
1086 void GenerateOopMap::interp_all() {
1087 bool change = true;
1088
1089 while (change && !_got_error) {
1090 change = false;
1091 for (int i = 0; i < _bb_count && !_got_error; i++) {
1092 BasicBlock *bb = &_basic_blocks[i];
1093 if (bb->changed()) {
1094 if (_got_error) return;
1095 change = true;
1096 bb->set_changed(false);
1097 interp_bb(bb);
1098 }
1099 }
1100 }
1101 }
1102
1103 void GenerateOopMap::interp_bb(BasicBlock *bb) {
1104
1105 // We do not want to do anything in case the basic-block has not been initialized. This
1106 // will happen in the case where there is dead-code hang around in a method.
1107 assert(bb->is_reachable(), "should be reachable or deadcode exist");
1108 restore_state(bb);
1109
1110 BytecodeStream itr(_method);
1111
1112 // Set iterator interval to be the current basicblock
1113 int lim_bci = next_bb_start_pc(bb);
1114 itr.set_interval(bb->_bci, lim_bci);
1115 assert(lim_bci != bb->_bci, "must be at least one instruction in a basicblock");
1116 itr.next(); // read first instruction
1117
1118 // Iterates through all bytecodes except the last in a basic block.
1119 // We handle the last one special, since there is controlflow change.
1120 while(itr.next_bci() < lim_bci && !_got_error) {
1121 if (_has_exceptions || _monitor_top != 0) {
1122 // We do not need to interpret the results of exceptional
1123 // continuation from this instruction when the method has no
1124 // exception handlers and the monitor stack is currently
1125 // empty.
1126 do_exception_edge(&itr);
1127 }
1128 interp1(&itr);
1129 itr.next();
1130 }
1131
1132 // Handle last instruction.
1133 if (!_got_error) {
1134 assert(itr.next_bci() == lim_bci, "must point to end");
1135 if (_has_exceptions || _monitor_top != 0) {
1136 do_exception_edge(&itr);
1137 }
1138 interp1(&itr);
1139
1140 bool fall_through = jump_targets_do(&itr, GenerateOopMap::merge_state, NULL);
1141 if (_got_error) return;
1142
1143 if (itr.code() == Bytecodes::_ret) {
1144 assert(!fall_through, "cannot be set if ret instruction");
1145 // Automatically handles 'wide' ret indicies
1146 ret_jump_targets_do(&itr, GenerateOopMap::merge_state, itr.get_index(), NULL);
1147 } else if (fall_through) {
1148 // Hit end of BB, but the instr. was a fall-through instruction,
1149 // so perform transition as if the BB ended in a "jump".
1150 if (lim_bci != bb[1]._bci) {
1151 verify_error("bytecodes fell through last instruction");
1152 return;
1153 }
1154 merge_state_into_bb(bb + 1);
1155 }
1156 }
1157 }
1158
1159 void GenerateOopMap::do_exception_edge(BytecodeStream* itr) {
1160 // Only check exception edge, if bytecode can trap
1161 if (!Bytecodes::can_trap(itr->code())) return;
1162 switch (itr->code()) {
1163 case Bytecodes::_aload_0:
1164 // These bytecodes can trap for rewriting. We need to assume that
1165 // they do not throw exceptions to make the monitor analysis work.
1166 return;
1167
1168 case Bytecodes::_ireturn:
1169 case Bytecodes::_lreturn:
1170 case Bytecodes::_freturn:
1171 case Bytecodes::_dreturn:
1172 case Bytecodes::_areturn:
1173 case Bytecodes::_return:
1174 // If the monitor stack height is not zero when we leave the method,
1175 // then we are either exiting with a non-empty stack or we have
1176 // found monitor trouble earlier in our analysis. In either case,
1177 // assume an exception could be taken here.
1178 if (_monitor_top == 0) {
1179 return;
1180 }
1181 break;
1182
1183 case Bytecodes::_monitorexit:
1184 // If the monitor stack height is bad_monitors, then we have detected a
1185 // monitor matching problem earlier in the analysis. If the
1186 // monitor stack height is 0, we are about to pop a monitor
1187 // off of an empty stack. In either case, the bytecode
1188 // could throw an exception.
1189 if (_monitor_top != bad_monitors && _monitor_top != 0) {
1190 return;
1191 }
1192 break;
1193 }
1194
1195 if (_has_exceptions) {
1196 int bci = itr->bci();
1197 ExceptionTable exct(method());
1198 for(int i = 0; i< exct.length(); i++) {
1199 int start_pc = exct.start_pc(i);
1200 int end_pc = exct.end_pc(i);
1201 int handler_pc = exct.handler_pc(i);
1202 int catch_type = exct.catch_type_index(i);
1203
1204 if (start_pc <= bci && bci < end_pc) {
1205 BasicBlock *excBB = get_basic_block_at(handler_pc);
1206 guarantee(excBB != NULL, "no basic block for exception");
1207 CellTypeState *excStk = excBB->stack();
1208 CellTypeState *cOpStck = stack();
1209 CellTypeState cOpStck_0 = cOpStck[0];
1210 int cOpStackTop = _stack_top;
1211
1212 // Exception stacks are always the same.
1213 assert(method()->max_stack() > 0, "sanity check");
1214
1215 // We remembered the size and first element of "cOpStck"
1216 // above; now we temporarily set them to the appropriate
1217 // values for an exception handler. */
1218 cOpStck[0] = CellTypeState::make_slot_ref(_max_locals);
1219 _stack_top = 1;
1220
1221 merge_state_into_bb(excBB);
1222
1223 // Now undo the temporary change.
1224 cOpStck[0] = cOpStck_0;
1225 _stack_top = cOpStackTop;
1226
1227 // If this is a "catch all" handler, then we do not need to
1228 // consider any additional handlers.
1229 if (catch_type == 0) {
1230 return;
1231 }
1232 }
1233 }
1234 }
1235
1236 // It is possible that none of the exception handlers would have caught
1237 // the exception. In this case, we will exit the method. We must
1238 // ensure that the monitor stack is empty in this case.
1239 if (_monitor_top == 0) {
1240 return;
1241 }
1242
1243 // We pessimistically assume that this exception can escape the
1244 // method. (It is possible that it will always be caught, but
1245 // we don't care to analyse the types of the catch clauses.)
1246
1247 // We don't set _monitor_top to bad_monitors because there are no successors
1248 // to this exceptional exit.
1249
1250 if (log_is_enabled(Info, monitormismatch) && _monitor_safe) {
1251 // We check _monitor_safe so that we only report the first mismatched
1252 // exceptional exit.
1253 report_monitor_mismatch("non-empty monitor stack at exceptional exit");
1254 }
1255 _monitor_safe = false;
1256
1257 }
1258
1259 void GenerateOopMap::report_monitor_mismatch(const char *msg) {
1260 ResourceMark rm;
1261 outputStream* out = Log(monitormismatch)::info_stream();
1262 out->print("Monitor mismatch in method ");
1263 method()->print_short_name(out);
1264 out->print_cr(": %s", msg);
1265 }
1266
1267 void GenerateOopMap::print_states(outputStream *os,
1268 CellTypeState* vec, int num) {
1269 for (int i = 0; i < num; i++) {
1270 vec[i].print(tty);
1271 }
1272 }
1273
1274 // Print the state values at the current bytecode.
1275 void GenerateOopMap::print_current_state(outputStream *os,
1276 BytecodeStream *currentBC,
1277 bool detailed) {
1278
1279 if (detailed) {
1280 os->print(" %4d vars = ", currentBC->bci());
1281 print_states(os, vars(), _max_locals);
1282 os->print(" %s", Bytecodes::name(currentBC->code()));
1283 switch(currentBC->code()) {
1284 case Bytecodes::_invokevirtual:
1285 case Bytecodes::_invokespecial:
1286 case Bytecodes::_invokestatic:
1287 case Bytecodes::_invokedynamic:
1288 case Bytecodes::_invokeinterface:
1289 int idx = currentBC->has_index_u4() ? currentBC->get_index_u4() : currentBC->get_index_u2_cpcache();
1290 ConstantPool* cp = method()->constants();
1291 int nameAndTypeIdx = cp->name_and_type_ref_index_at(idx);
1292 int signatureIdx = cp->signature_ref_index_at(nameAndTypeIdx);
1293 Symbol* signature = cp->symbol_at(signatureIdx);
1294 os->print("%s", signature->as_C_string());
1295 }
1296 os->cr();
1297 os->print(" stack = ");
1298 print_states(os, stack(), _stack_top);
1299 os->cr();
1300 if (_monitor_top != bad_monitors) {
1301 os->print(" monitors = ");
1302 print_states(os, monitors(), _monitor_top);
1303 } else {
1304 os->print(" [bad monitor stack]");
1305 }
1306 os->cr();
1307 } else {
1308 os->print(" %4d vars = '%s' ", currentBC->bci(), state_vec_to_string(vars(), _max_locals));
1309 os->print(" stack = '%s' ", state_vec_to_string(stack(), _stack_top));
1310 if (_monitor_top != bad_monitors) {
1311 os->print(" monitors = '%s' \t%s", state_vec_to_string(monitors(), _monitor_top), Bytecodes::name(currentBC->code()));
1312 } else {
1313 os->print(" [bad monitor stack]");
1314 }
1315 switch(currentBC->code()) {
1316 case Bytecodes::_invokevirtual:
1317 case Bytecodes::_invokespecial:
1318 case Bytecodes::_invokestatic:
1319 case Bytecodes::_invokedynamic:
1320 case Bytecodes::_invokeinterface:
1321 int idx = currentBC->has_index_u4() ? currentBC->get_index_u4() : currentBC->get_index_u2_cpcache();
1322 ConstantPool* cp = method()->constants();
1323 int nameAndTypeIdx = cp->name_and_type_ref_index_at(idx);
1324 int signatureIdx = cp->signature_ref_index_at(nameAndTypeIdx);
1325 Symbol* signature = cp->symbol_at(signatureIdx);
1326 os->print("%s", signature->as_C_string());
1327 }
1328 os->cr();
1329 }
1330 }
1331
1332 // Sets the current state to be the state after executing the
1333 // current instruction, starting in the current state.
1334 void GenerateOopMap::interp1(BytecodeStream *itr) {
1335 if (TraceNewOopMapGeneration) {
1336 print_current_state(tty, itr, TraceNewOopMapGenerationDetailed);
1337 }
1338
1339 // Should we report the results? Result is reported *before* the instruction at the current bci is executed.
1340 // However, not for calls. For calls we do not want to include the arguments, so we postpone the reporting until
1341 // they have been popped (in method ppl).
1342 if (_report_result == true) {
1343 switch(itr->code()) {
1344 case Bytecodes::_invokevirtual:
1345 case Bytecodes::_invokespecial:
1346 case Bytecodes::_invokestatic:
1347 case Bytecodes::_invokedynamic:
1348 case Bytecodes::_invokeinterface:
1349 _itr_send = itr;
1350 _report_result_for_send = true;
1351 break;
1352 default:
1353 fill_stackmap_for_opcodes(itr, vars(), stack(), _stack_top);
1354 break;
1355 }
1356 }
1357
1358 // abstract interpretation of current opcode
1359 switch(itr->code()) {
1360 case Bytecodes::_nop: break;
1361 case Bytecodes::_goto: break;
1362 case Bytecodes::_goto_w: break;
1363 case Bytecodes::_iinc: break;
1364 case Bytecodes::_return: do_return_monitor_check();
1365 break;
1366
1367 case Bytecodes::_aconst_null:
1368 case Bytecodes::_new: ppush1(CellTypeState::make_line_ref(itr->bci()));
1369 break;
1370
1371 case Bytecodes::_iconst_m1:
1372 case Bytecodes::_iconst_0:
1373 case Bytecodes::_iconst_1:
1374 case Bytecodes::_iconst_2:
1375 case Bytecodes::_iconst_3:
1376 case Bytecodes::_iconst_4:
1377 case Bytecodes::_iconst_5:
1378 case Bytecodes::_fconst_0:
1379 case Bytecodes::_fconst_1:
1380 case Bytecodes::_fconst_2:
1381 case Bytecodes::_bipush:
1382 case Bytecodes::_sipush: ppush1(valCTS); break;
1383
1384 case Bytecodes::_lconst_0:
1385 case Bytecodes::_lconst_1:
1386 case Bytecodes::_dconst_0:
1387 case Bytecodes::_dconst_1: ppush(vvCTS); break;
1388
1389 case Bytecodes::_ldc2_w: ppush(vvCTS); break;
1390
1391 case Bytecodes::_ldc: // fall through:
1392 case Bytecodes::_ldc_w: do_ldc(itr->bci()); break;
1393
1394 case Bytecodes::_iload:
1395 case Bytecodes::_fload: ppload(vCTS, itr->get_index()); break;
1396
1397 case Bytecodes::_lload:
1398 case Bytecodes::_dload: ppload(vvCTS,itr->get_index()); break;
1399
1400 case Bytecodes::_aload: ppload(rCTS, itr->get_index()); break;
1401
1402 case Bytecodes::_iload_0:
1403 case Bytecodes::_fload_0: ppload(vCTS, 0); break;
1404 case Bytecodes::_iload_1:
1405 case Bytecodes::_fload_1: ppload(vCTS, 1); break;
1406 case Bytecodes::_iload_2:
1407 case Bytecodes::_fload_2: ppload(vCTS, 2); break;
1408 case Bytecodes::_iload_3:
1409 case Bytecodes::_fload_3: ppload(vCTS, 3); break;
1410
1411 case Bytecodes::_lload_0:
1412 case Bytecodes::_dload_0: ppload(vvCTS, 0); break;
1413 case Bytecodes::_lload_1:
1414 case Bytecodes::_dload_1: ppload(vvCTS, 1); break;
1415 case Bytecodes::_lload_2:
1416 case Bytecodes::_dload_2: ppload(vvCTS, 2); break;
1417 case Bytecodes::_lload_3:
1418 case Bytecodes::_dload_3: ppload(vvCTS, 3); break;
1419
1420 case Bytecodes::_aload_0: ppload(rCTS, 0); break;
1421 case Bytecodes::_aload_1: ppload(rCTS, 1); break;
1422 case Bytecodes::_aload_2: ppload(rCTS, 2); break;
1423 case Bytecodes::_aload_3: ppload(rCTS, 3); break;
1424
1425 case Bytecodes::_iaload:
1426 case Bytecodes::_faload:
1427 case Bytecodes::_baload:
1428 case Bytecodes::_caload:
1429 case Bytecodes::_saload: pp(vrCTS, vCTS); break;
1430
1431 case Bytecodes::_laload: pp(vrCTS, vvCTS); break;
1432 case Bytecodes::_daload: pp(vrCTS, vvCTS); break;
1433
1434 case Bytecodes::_aaload: pp_new_ref(vrCTS, itr->bci()); break;
1435
1436 case Bytecodes::_istore:
1437 case Bytecodes::_fstore: ppstore(vCTS, itr->get_index()); break;
1438
1439 case Bytecodes::_lstore:
1440 case Bytecodes::_dstore: ppstore(vvCTS, itr->get_index()); break;
1441
1442 case Bytecodes::_astore: do_astore(itr->get_index()); break;
1443
1444 case Bytecodes::_istore_0:
1445 case Bytecodes::_fstore_0: ppstore(vCTS, 0); break;
1446 case Bytecodes::_istore_1:
1447 case Bytecodes::_fstore_1: ppstore(vCTS, 1); break;
1448 case Bytecodes::_istore_2:
1449 case Bytecodes::_fstore_2: ppstore(vCTS, 2); break;
1450 case Bytecodes::_istore_3:
1451 case Bytecodes::_fstore_3: ppstore(vCTS, 3); break;
1452
1453 case Bytecodes::_lstore_0:
1454 case Bytecodes::_dstore_0: ppstore(vvCTS, 0); break;
1455 case Bytecodes::_lstore_1:
1456 case Bytecodes::_dstore_1: ppstore(vvCTS, 1); break;
1457 case Bytecodes::_lstore_2:
1458 case Bytecodes::_dstore_2: ppstore(vvCTS, 2); break;
1459 case Bytecodes::_lstore_3:
1460 case Bytecodes::_dstore_3: ppstore(vvCTS, 3); break;
1461
1462 case Bytecodes::_astore_0: do_astore(0); break;
1463 case Bytecodes::_astore_1: do_astore(1); break;
1464 case Bytecodes::_astore_2: do_astore(2); break;
1465 case Bytecodes::_astore_3: do_astore(3); break;
1466
1467 case Bytecodes::_iastore:
1468 case Bytecodes::_fastore:
1469 case Bytecodes::_bastore:
1470 case Bytecodes::_castore:
1471 case Bytecodes::_sastore: ppop(vvrCTS); break;
1472 case Bytecodes::_lastore:
1473 case Bytecodes::_dastore: ppop(vvvrCTS); break;
1474 case Bytecodes::_aastore: ppop(rvrCTS); break;
1475
1476 case Bytecodes::_pop: ppop_any(1); break;
1477 case Bytecodes::_pop2: ppop_any(2); break;
1478
1479 case Bytecodes::_dup: ppdupswap(1, "11"); break;
1480 case Bytecodes::_dup_x1: ppdupswap(2, "121"); break;
1481 case Bytecodes::_dup_x2: ppdupswap(3, "1321"); break;
1482 case Bytecodes::_dup2: ppdupswap(2, "2121"); break;
1483 case Bytecodes::_dup2_x1: ppdupswap(3, "21321"); break;
1484 case Bytecodes::_dup2_x2: ppdupswap(4, "214321"); break;
1485 case Bytecodes::_swap: ppdupswap(2, "12"); break;
1486
1487 case Bytecodes::_iadd:
1488 case Bytecodes::_fadd:
1489 case Bytecodes::_isub:
1490 case Bytecodes::_fsub:
1491 case Bytecodes::_imul:
1492 case Bytecodes::_fmul:
1493 case Bytecodes::_idiv:
1494 case Bytecodes::_fdiv:
1495 case Bytecodes::_irem:
1496 case Bytecodes::_frem:
1497 case Bytecodes::_ishl:
1498 case Bytecodes::_ishr:
1499 case Bytecodes::_iushr:
1500 case Bytecodes::_iand:
1501 case Bytecodes::_ior:
1502 case Bytecodes::_ixor:
1503 case Bytecodes::_l2f:
1504 case Bytecodes::_l2i:
1505 case Bytecodes::_d2f:
1506 case Bytecodes::_d2i:
1507 case Bytecodes::_fcmpl:
1508 case Bytecodes::_fcmpg: pp(vvCTS, vCTS); break;
1509
1510 case Bytecodes::_ladd:
1511 case Bytecodes::_dadd:
1512 case Bytecodes::_lsub:
1513 case Bytecodes::_dsub:
1514 case Bytecodes::_lmul:
1515 case Bytecodes::_dmul:
1516 case Bytecodes::_ldiv:
1517 case Bytecodes::_ddiv:
1518 case Bytecodes::_lrem:
1519 case Bytecodes::_drem:
1520 case Bytecodes::_land:
1521 case Bytecodes::_lor:
1522 case Bytecodes::_lxor: pp(vvvvCTS, vvCTS); break;
1523
1524 case Bytecodes::_ineg:
1525 case Bytecodes::_fneg:
1526 case Bytecodes::_i2f:
1527 case Bytecodes::_f2i:
1528 case Bytecodes::_i2c:
1529 case Bytecodes::_i2s:
1530 case Bytecodes::_i2b: pp(vCTS, vCTS); break;
1531
1532 case Bytecodes::_lneg:
1533 case Bytecodes::_dneg:
1534 case Bytecodes::_l2d:
1535 case Bytecodes::_d2l: pp(vvCTS, vvCTS); break;
1536
1537 case Bytecodes::_lshl:
1538 case Bytecodes::_lshr:
1539 case Bytecodes::_lushr: pp(vvvCTS, vvCTS); break;
1540
1541 case Bytecodes::_i2l:
1542 case Bytecodes::_i2d:
1543 case Bytecodes::_f2l:
1544 case Bytecodes::_f2d: pp(vCTS, vvCTS); break;
1545
1546 case Bytecodes::_lcmp: pp(vvvvCTS, vCTS); break;
1547 case Bytecodes::_dcmpl:
1548 case Bytecodes::_dcmpg: pp(vvvvCTS, vCTS); break;
1549
1550 case Bytecodes::_ifeq:
1551 case Bytecodes::_ifne:
1552 case Bytecodes::_iflt:
1553 case Bytecodes::_ifge:
1554 case Bytecodes::_ifgt:
1555 case Bytecodes::_ifle:
1556 case Bytecodes::_tableswitch: ppop1(valCTS);
1557 break;
1558 case Bytecodes::_ireturn:
1559 case Bytecodes::_freturn: do_return_monitor_check();
1560 ppop1(valCTS);
1561 break;
1562 case Bytecodes::_if_icmpeq:
1563 case Bytecodes::_if_icmpne:
1564 case Bytecodes::_if_icmplt:
1565 case Bytecodes::_if_icmpge:
1566 case Bytecodes::_if_icmpgt:
1567 case Bytecodes::_if_icmple: ppop(vvCTS);
1568 break;
1569
1570 case Bytecodes::_lreturn: do_return_monitor_check();
1571 ppop(vvCTS);
1572 break;
1573
1574 case Bytecodes::_dreturn: do_return_monitor_check();
1575 ppop(vvCTS);
1576 break;
1577
1578 case Bytecodes::_if_acmpeq:
1579 case Bytecodes::_if_acmpne: ppop(rrCTS); break;
1580
1581 case Bytecodes::_jsr: do_jsr(itr->dest()); break;
1582 case Bytecodes::_jsr_w: do_jsr(itr->dest_w()); break;
1583
1584 case Bytecodes::_getstatic: do_field(true, true, itr->get_index_u2_cpcache(), itr->bci()); break;
1585 case Bytecodes::_putstatic: do_field(false, true, itr->get_index_u2_cpcache(), itr->bci()); break;
1586 case Bytecodes::_getfield: do_field(true, false, itr->get_index_u2_cpcache(), itr->bci()); break;
1587 case Bytecodes::_putfield: do_field(false, false, itr->get_index_u2_cpcache(), itr->bci()); break;
1588
1589 case Bytecodes::_invokevirtual:
1590 case Bytecodes::_invokespecial: do_method(false, false, itr->get_index_u2_cpcache(), itr->bci()); break;
1591 case Bytecodes::_invokestatic: do_method(true, false, itr->get_index_u2_cpcache(), itr->bci()); break;
1592 case Bytecodes::_invokedynamic: do_method(true, false, itr->get_index_u4(), itr->bci()); break;
1593 case Bytecodes::_invokeinterface: do_method(false, true, itr->get_index_u2_cpcache(), itr->bci()); break;
1594 case Bytecodes::_newarray:
1595 case Bytecodes::_anewarray: pp_new_ref(vCTS, itr->bci()); break;
1596 case Bytecodes::_checkcast: do_checkcast(); break;
1597 case Bytecodes::_arraylength:
1598 case Bytecodes::_instanceof: pp(rCTS, vCTS); break;
1599 case Bytecodes::_monitorenter: do_monitorenter(itr->bci()); break;
1600 case Bytecodes::_monitorexit: do_monitorexit(itr->bci()); break;
1601
1602 case Bytecodes::_athrow: // handled by do_exception_edge() BUT ...
1603 // vlh(apple): do_exception_edge() does not get
1604 // called if method has no exception handlers
1605 if ((!_has_exceptions) && (_monitor_top > 0)) {
1606 _monitor_safe = false;
1607 }
1608 break;
1609
1610 case Bytecodes::_areturn: do_return_monitor_check();
1611 ppop1(refCTS);
1612 break;
1613 case Bytecodes::_ifnull:
1614 case Bytecodes::_ifnonnull: ppop1(refCTS); break;
1615 case Bytecodes::_multianewarray: do_multianewarray(*(itr->bcp()+3), itr->bci()); break;
1616
1617 case Bytecodes::_wide: fatal("Iterator should skip this bytecode"); break;
1618 case Bytecodes::_ret: break;
1619
1620 // Java opcodes
1621 case Bytecodes::_lookupswitch: ppop1(valCTS); break;
1622
1623 default:
1624 tty->print("unexpected opcode: %d\n", itr->code());
1625 ShouldNotReachHere();
1626 break;
1627 }
1628 }
1629
1630 void GenerateOopMap::check_type(CellTypeState expected, CellTypeState actual) {
1631 if (!expected.equal_kind(actual)) {
1632 verify_error("wrong type on stack (found: %c expected: %c)", actual.to_char(), expected.to_char());
1633 }
1634 }
1635
1636 void GenerateOopMap::ppstore(CellTypeState *in, int loc_no) {
1637 while(!(*in).is_bottom()) {
1638 CellTypeState expected =*in++;
1639 CellTypeState actual = pop();
1640 check_type(expected, actual);
1641 assert(loc_no >= 0, "sanity check");
1642 set_var(loc_no++, actual);
1643 }
1644 }
1645
1646 void GenerateOopMap::ppload(CellTypeState *out, int loc_no) {
1647 while(!(*out).is_bottom()) {
1648 CellTypeState out1 = *out++;
1649 CellTypeState vcts = get_var(loc_no);
1650 assert(out1.can_be_reference() || out1.can_be_value(),
1651 "can only load refs. and values.");
1652 if (out1.is_reference()) {
1653 assert(loc_no>=0, "sanity check");
1654 if (!vcts.is_reference()) {
1655 // We were asked to push a reference, but the type of the
1656 // variable can be something else
1657 _conflict = true;
1658 if (vcts.can_be_uninit()) {
1659 // It is a ref-uninit conflict (at least). If there are other
1660 // problems, we'll get them in the next round
1661 add_to_ref_init_set(loc_no);
1662 vcts = out1;
1663 } else {
1664 // It wasn't a ref-uninit conflict. So must be a
1665 // ref-val or ref-pc conflict. Split the variable.
1666 record_refval_conflict(loc_no);
1667 vcts = out1;
1668 }
1669 push(out1); // recover...
1670 } else {
1671 push(vcts); // preserve reference.
1672 }
1673 // Otherwise it is a conflict, but one that verification would
1674 // have caught if illegal. In particular, it can't be a topCTS
1675 // resulting from mergeing two difference pcCTS's since the verifier
1676 // would have rejected any use of such a merge.
1677 } else {
1678 push(out1); // handle val/init conflict
1679 }
1680 loc_no++;
1681 }
1682 }
1683
1684 void GenerateOopMap::ppdupswap(int poplen, const char *out) {
1685 CellTypeState actual[5];
1686 assert(poplen < 5, "this must be less than length of actual vector");
1687
1688 // pop all arguments
1689 for (int i = 0; i < poplen; i++) { actual[i] = pop(); }
1690 // Field _state is uninitialized when calling push.
1691 for (int i = poplen; i < 5; i++) { actual[i] = CellTypeState::uninit; }
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 }