1 /*
2 * Copyright (c) 1997, 2021, 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 "classfile/vmSymbols.hpp"
27 #include "interpreter/bytecodeStream.hpp"
28 #include "logging/log.hpp"
29 #include "logging/logStream.hpp"
30 #include "memory/allocation.inline.hpp"
31 #include "memory/resourceArea.hpp"
32 #include "oops/constantPool.hpp"
33 #include "oops/generateOopMap.hpp"
34 #include "oops/oop.inline.hpp"
35 #include "oops/symbol.hpp"
36 #include "runtime/handles.inline.hpp"
37 #include "runtime/java.hpp"
38 #include "runtime/os.hpp"
39 #include "runtime/relocator.hpp"
40 #include "runtime/timerTrace.hpp"
41 #include "utilities/bitMap.inline.hpp"
42 #include "utilities/ostream.hpp"
43
44 //
45 //
46 // Compute stack layouts for each instruction in method.
47 //
48 // Problems:
49 // - What to do about jsr with different types of local vars?
50 // Need maps that are conditional on jsr path?
51 // - Jsr and exceptions should be done more efficiently (the retAddr stuff)
52 //
53 // Alternative:
54 // - Could extend verifier to provide this information.
55 // For: one fewer abstract interpreter to maintain. Against: the verifier
56 // solves a bigger problem so slower (undesirable to force verification of
57 // everything?).
58 //
59 // Algorithm:
60 // Partition bytecodes into basic blocks
61 // For each basic block: store entry state (vars, stack). For instructions
62 // inside basic blocks we do not store any state (instead we recompute it
63 // from state produced by previous instruction).
64 //
65 // Perform abstract interpretation of bytecodes over this lattice:
66 //
67 // _--'#'--_
68 // / / \ \
69 // / / \ \
70 // / | | \
71 // 'r' 'v' 'p' ' '
72 // \ | | /
73 // \ \ / /
74 // \ \ / /
75 // -- '@' --
76 //
77 // '#' top, result of conflict merge
78 // 'r' reference type
79 // 'v' value type
80 // 'p' pc type for jsr/ret
81 // ' ' uninitialized; never occurs on operand stack in Java
82 // '@' bottom/unexecuted; initial state each bytecode.
83 //
84 // Basic block headers are the only merge points. We use this iteration to
85 // compute the information:
86 //
87 // find basic blocks;
88 // initialize them with uninitialized state;
89 // initialize first BB according to method signature;
90 // mark first BB changed
91 // while (some BB is changed) do {
92 // perform abstract interpration of all bytecodes in BB;
93 // merge exit state of BB into entry state of all successor BBs,
94 // noting if any of these change;
95 // }
96 //
97 // One additional complication is necessary. The jsr instruction pushes
98 // a return PC on the stack (a 'p' type in the abstract interpretation).
99 // To be able to process "ret" bytecodes, we keep track of these return
100 // PC's in a 'retAddrs' structure in abstract interpreter context (when
101 // processing a "ret" bytecodes, it is not sufficient to know that it gets
102 // an argument of the right type 'p'; we need to know which address it
103 // returns to).
104 //
105 // (Note this comment is borrowed form the original author of the algorithm)
106
107 // ComputeCallStack
108 //
109 // Specialization of SignatureIterator - compute the effects of a call
110 //
111 class ComputeCallStack : public SignatureIterator {
112 CellTypeState *_effect;
113 int _idx;
114
115 void setup();
116 void set(CellTypeState state) { _effect[_idx++] = state; }
117 int length() { return _idx; };
118
119 friend class SignatureIterator; // so do_parameters_on can call do_type
120 void do_type(BasicType type, bool for_return = false) {
121 if (for_return && type == T_VOID) {
122 set(CellTypeState::bottom);
123 } else if (is_reference_type(type)) {
124 set(CellTypeState::ref);
125 } else {
126 assert(is_java_primitive(type), "");
127 set(CellTypeState::value);
128 if (is_double_word_type(type)) {
129 set(CellTypeState::value);
130 }
131 }
132 }
133
134 public:
135 ComputeCallStack(Symbol* signature) : SignatureIterator(signature) {};
136
137 // Compute methods
138 int compute_for_parameters(bool is_static, CellTypeState *effect) {
139 _idx = 0;
140 _effect = effect;
141
142 if (!is_static) {
143 effect[_idx++] = CellTypeState::ref;
144 }
145
146 do_parameters_on(this);
147
148 return length();
149 };
150
151 int compute_for_returntype(CellTypeState *effect) {
152 _idx = 0;
153 _effect = effect;
154 do_type(return_type(), true);
155 set(CellTypeState::bottom); // Always terminate with a bottom state, so ppush works
156
157 return length();
158 }
159 };
160
161 //=========================================================================================
162 // ComputeEntryStack
163 //
164 // Specialization of SignatureIterator - in order to set up first stack frame
165 //
166 class ComputeEntryStack : public SignatureIterator {
167 CellTypeState *_effect;
168 int _idx;
169
170 void setup();
171 void set(CellTypeState state) { _effect[_idx++] = state; }
172 int length() { return _idx; };
173
174 friend class SignatureIterator; // so do_parameters_on can call do_type
175 void do_type(BasicType type, bool for_return = false) {
176 if (for_return && type == T_VOID) {
177 set(CellTypeState::bottom);
178 } else if (is_reference_type(type)) {
179 set(CellTypeState::make_slot_ref(_idx));
180 } else {
181 assert(is_java_primitive(type), "");
182 set(CellTypeState::value);
183 if (is_double_word_type(type)) {
184 set(CellTypeState::value);
185 }
186 }
187 }
188
189 public:
190 ComputeEntryStack(Symbol* signature) : SignatureIterator(signature) {};
191
192 // Compute methods
193 int compute_for_parameters(bool is_static, CellTypeState *effect) {
194 _idx = 0;
195 _effect = effect;
196
197 if (!is_static)
198 effect[_idx++] = CellTypeState::make_slot_ref(0);
199
200 do_parameters_on(this);
201
202 return length();
203 };
204
205 int compute_for_returntype(CellTypeState *effect) {
206 _idx = 0;
207 _effect = effect;
208 do_type(return_type(), true);
209 set(CellTypeState::bottom); // Always terminate with a bottom state, so ppush works
210
211 return length();
212 }
213 };
214
215 //=====================================================================================
216 //
217 // Implementation of RetTable/RetTableEntry
218 //
219 // Contains function to itereate through all bytecodes
220 // and find all return entry points
221 //
222 int RetTable::_init_nof_entries = 10;
223 int RetTableEntry::_init_nof_jsrs = 5;
224
225 RetTableEntry::RetTableEntry(int target, RetTableEntry *next) {
226 _target_bci = target;
227 _jsrs = new GrowableArray<intptr_t>(_init_nof_jsrs);
228 _next = next;
229 }
230
231 void RetTableEntry::add_delta(int bci, int delta) {
232 if (_target_bci > bci) _target_bci += delta;
233
234 for (int k = 0; k < _jsrs->length(); k++) {
235 int jsr = _jsrs->at(k);
236 if (jsr > bci) _jsrs->at_put(k, jsr+delta);
237 }
238 }
239
240 void RetTable::compute_ret_table(const methodHandle& method) {
241 BytecodeStream i(method);
242 Bytecodes::Code bytecode;
243
244 while( (bytecode = i.next()) >= 0) {
245 switch (bytecode) {
246 case Bytecodes::_jsr:
247 add_jsr(i.next_bci(), i.dest());
248 break;
249 case Bytecodes::_jsr_w:
250 add_jsr(i.next_bci(), i.dest_w());
251 break;
252 default:
253 break;
254 }
255 }
256 }
257
258 void RetTable::add_jsr(int return_bci, int target_bci) {
259 RetTableEntry* entry = _first;
260
261 // Scan table for entry
262 for (;entry && entry->target_bci() != target_bci; entry = entry->next());
263
264 if (!entry) {
265 // Allocate new entry and put in list
266 entry = new RetTableEntry(target_bci, _first);
267 _first = entry;
268 }
269
270 // Now "entry" is set. Make sure that the entry is initialized
271 // and has room for the new jsr.
272 entry->add_jsr(return_bci);
273 }
274
275 RetTableEntry* RetTable::find_jsrs_for_target(int targBci) {
276 RetTableEntry *cur = _first;
277
278 while(cur) {
279 assert(cur->target_bci() != -1, "sanity check");
280 if (cur->target_bci() == targBci) return cur;
281 cur = cur->next();
282 }
283 ShouldNotReachHere();
284 return NULL;
285 }
286
287 // The instruction at bci is changing size by "delta". Update the return map.
288 void RetTable::update_ret_table(int bci, int delta) {
289 RetTableEntry *cur = _first;
290 while(cur) {
291 cur->add_delta(bci, delta);
292 cur = cur->next();
293 }
294 }
295
296 //
297 // Celltype state
298 //
299
300 CellTypeState CellTypeState::bottom = CellTypeState::make_bottom();
301 CellTypeState CellTypeState::uninit = CellTypeState::make_any(uninit_value);
302 CellTypeState CellTypeState::ref = CellTypeState::make_any(ref_conflict);
303 CellTypeState CellTypeState::value = CellTypeState::make_any(val_value);
304 CellTypeState CellTypeState::refUninit = CellTypeState::make_any(ref_conflict | uninit_value);
305 CellTypeState CellTypeState::top = CellTypeState::make_top();
306 CellTypeState CellTypeState::addr = CellTypeState::make_any(addr_conflict);
307
308 // Commonly used constants
309 static CellTypeState epsilonCTS[1] = { CellTypeState::bottom };
310 static CellTypeState refCTS = CellTypeState::ref;
311 static CellTypeState valCTS = CellTypeState::value;
312 static CellTypeState vCTS[2] = { CellTypeState::value, CellTypeState::bottom };
313 static CellTypeState rCTS[2] = { CellTypeState::ref, CellTypeState::bottom };
314 static CellTypeState rrCTS[3] = { CellTypeState::ref, CellTypeState::ref, CellTypeState::bottom };
315 static CellTypeState vrCTS[3] = { CellTypeState::value, CellTypeState::ref, CellTypeState::bottom };
316 static CellTypeState vvCTS[3] = { CellTypeState::value, CellTypeState::value, CellTypeState::bottom };
317 static CellTypeState rvrCTS[4] = { CellTypeState::ref, CellTypeState::value, CellTypeState::ref, CellTypeState::bottom };
318 static CellTypeState vvrCTS[4] = { CellTypeState::value, CellTypeState::value, CellTypeState::ref, CellTypeState::bottom };
319 static CellTypeState vvvCTS[4] = { CellTypeState::value, CellTypeState::value, CellTypeState::value, CellTypeState::bottom };
320 static CellTypeState vvvrCTS[5] = { CellTypeState::value, CellTypeState::value, CellTypeState::value, CellTypeState::ref, CellTypeState::bottom };
321 static CellTypeState vvvvCTS[5] = { CellTypeState::value, CellTypeState::value, CellTypeState::value, CellTypeState::value, CellTypeState::bottom };
322
323 char CellTypeState::to_char() const {
324 if (can_be_reference()) {
325 if (can_be_value() || can_be_address())
326 return '#'; // Conflict that needs to be rewritten
327 else
328 return 'r';
329 } else if (can_be_value())
330 return 'v';
331 else if (can_be_address())
332 return 'p';
333 else if (can_be_uninit())
334 return ' ';
335 else
336 return '@';
337 }
338
339
340 // Print a detailed CellTypeState. Indicate all bits that are set. If
341 // the CellTypeState represents an address or a reference, print the
342 // value of the additional information.
343 void CellTypeState::print(outputStream *os) {
344 if (can_be_address()) {
345 os->print("(p");
346 } else {
347 os->print("( ");
348 }
349 if (can_be_reference()) {
350 os->print("r");
351 } else {
352 os->print(" ");
353 }
354 if (can_be_value()) {
355 os->print("v");
356 } else {
357 os->print(" ");
358 }
359 if (can_be_uninit()) {
360 os->print("u|");
361 } else {
362 os->print(" |");
363 }
364 if (is_info_top()) {
365 os->print("Top)");
366 } else if (is_info_bottom()) {
367 os->print("Bot)");
368 } else {
369 if (is_reference()) {
370 int info = get_info();
371 int data = info & ~(ref_not_lock_bit | ref_slot_bit);
372 if (info & ref_not_lock_bit) {
373 // Not a monitor lock reference.
374 if (info & ref_slot_bit) {
375 // slot
376 os->print("slot%d)", data);
377 } else {
378 // line
379 os->print("line%d)", data);
380 }
381 } else {
382 // lock
383 os->print("lock%d)", data);
384 }
385 } else {
386 os->print("%d)", get_info());
387 }
388 }
389 }
390
391 //
392 // Basicblock handling methods
393 //
394
395 void GenerateOopMap::initialize_bb() {
396 _gc_points = 0;
397 _bb_count = 0;
398 _bb_hdr_bits.reinitialize(method()->code_size());
399 }
400
401 void GenerateOopMap::bb_mark_fct(GenerateOopMap *c, int bci, int *data) {
402 assert(bci>= 0 && bci < c->method()->code_size(), "index out of bounds");
403 if (c->is_bb_header(bci))
404 return;
405
406 if (TraceNewOopMapGeneration) {
407 tty->print_cr("Basicblock#%d begins at: %d", c->_bb_count, bci);
408 }
409 c->set_bbmark_bit(bci);
410 c->_bb_count++;
411 }
412
413
414 void GenerateOopMap::mark_bbheaders_and_count_gc_points() {
415 initialize_bb();
416
417 bool fellThrough = false; // False to get first BB marked.
418
419 // First mark all exception handlers as start of a basic-block
420 ExceptionTable excps(method());
421 for(int i = 0; i < excps.length(); i ++) {
422 bb_mark_fct(this, excps.handler_pc(i), NULL);
423 }
424
425 // Then iterate through the code
426 BytecodeStream bcs(_method);
427 Bytecodes::Code bytecode;
428
429 while( (bytecode = bcs.next()) >= 0) {
430 int bci = bcs.bci();
431
432 if (!fellThrough)
433 bb_mark_fct(this, bci, NULL);
434
435 fellThrough = jump_targets_do(&bcs, &GenerateOopMap::bb_mark_fct, NULL);
436
437 /* We will also mark successors of jsr's as basic block headers. */
438 switch (bytecode) {
439 case Bytecodes::_jsr:
440 assert(!fellThrough, "should not happen");
441 bb_mark_fct(this, bci + Bytecodes::length_for(bytecode), NULL);
442 break;
443 case Bytecodes::_jsr_w:
444 assert(!fellThrough, "should not happen");
445 bb_mark_fct(this, bci + Bytecodes::length_for(bytecode), NULL);
446 break;
447 default:
448 break;
449 }
450
451 if (possible_gc_point(&bcs))
452 _gc_points++;
453 }
454 }
455
456 void GenerateOopMap::set_bbmark_bit(int bci) {
457 _bb_hdr_bits.at_put(bci, true);
458 }
459
460 void GenerateOopMap::reachable_basicblock(GenerateOopMap *c, int bci, int *data) {
461 assert(bci>= 0 && bci < c->method()->code_size(), "index out of bounds");
462 BasicBlock* bb = c->get_basic_block_at(bci);
463 if (bb->is_dead()) {
464 bb->mark_as_alive();
465 *data = 1; // Mark basicblock as changed
466 }
467 }
468
469
470 void GenerateOopMap::mark_reachable_code() {
471 int change = 1; // int to get function pointers to work
472
473 // Mark entry basic block as alive and all exception handlers
474 _basic_blocks[0].mark_as_alive();
475 ExceptionTable excps(method());
476 for(int i = 0; i < excps.length(); i++) {
477 BasicBlock *bb = get_basic_block_at(excps.handler_pc(i));
478 // If block is not already alive (due to multiple exception handlers to same bb), then
479 // make it alive
480 if (bb->is_dead()) bb->mark_as_alive();
481 }
482
483 BytecodeStream bcs(_method);
484
485 // Iterate through all basic blocks until we reach a fixpoint
486 while (change) {
487 change = 0;
488
489 for (int i = 0; i < _bb_count; i++) {
490 BasicBlock *bb = &_basic_blocks[i];
491 if (bb->is_alive()) {
492 // Position bytecodestream at last bytecode in basicblock
493 bcs.set_start(bb->_end_bci);
494 bcs.next();
495 Bytecodes::Code bytecode = bcs.code();
496 int bci = bcs.bci();
497 assert(bci == bb->_end_bci, "wrong bci");
498
499 bool fell_through = jump_targets_do(&bcs, &GenerateOopMap::reachable_basicblock, &change);
500
501 // We will also mark successors of jsr's as alive.
502 switch (bytecode) {
503 case Bytecodes::_jsr:
504 case Bytecodes::_jsr_w:
505 assert(!fell_through, "should not happen");
506 reachable_basicblock(this, bci + Bytecodes::length_for(bytecode), &change);
507 break;
508 default:
509 break;
510 }
511 if (fell_through) {
512 // Mark successor as alive
513 if (bb[1].is_dead()) {
514 bb[1].mark_as_alive();
515 change = 1;
516 }
517 }
518 }
519 }
520 }
521 }
522
523 /* If the current instruction in "c" has no effect on control flow,
524 returns "true". Otherwise, calls "jmpFct" one or more times, with
525 "c", an appropriate "pcDelta", and "data" as arguments, then
526 returns "false". There is one exception: if the current
527 instruction is a "ret", returns "false" without calling "jmpFct".
528 Arrangements for tracking the control flow of a "ret" must be made
529 externally. */
530 bool GenerateOopMap::jump_targets_do(BytecodeStream *bcs, jmpFct_t jmpFct, int *data) {
531 int bci = bcs->bci();
532
533 switch (bcs->code()) {
534 case Bytecodes::_ifeq:
535 case Bytecodes::_ifne:
536 case Bytecodes::_iflt:
537 case Bytecodes::_ifge:
538 case Bytecodes::_ifgt:
539 case Bytecodes::_ifle:
540 case Bytecodes::_if_icmpeq:
541 case Bytecodes::_if_icmpne:
542 case Bytecodes::_if_icmplt:
543 case Bytecodes::_if_icmpge:
544 case Bytecodes::_if_icmpgt:
545 case Bytecodes::_if_icmple:
546 case Bytecodes::_if_acmpeq:
547 case Bytecodes::_if_acmpne:
548 case Bytecodes::_ifnull:
549 case Bytecodes::_ifnonnull:
550 (*jmpFct)(this, bcs->dest(), data);
551 (*jmpFct)(this, bci + 3, data);
552 break;
553
554 case Bytecodes::_goto:
555 (*jmpFct)(this, bcs->dest(), data);
556 break;
557 case Bytecodes::_goto_w:
558 (*jmpFct)(this, bcs->dest_w(), data);
559 break;
560 case Bytecodes::_tableswitch:
561 { Bytecode_tableswitch tableswitch(method(), bcs->bcp());
562 int len = tableswitch.length();
563
564 (*jmpFct)(this, bci + tableswitch.default_offset(), data); /* Default. jump address */
565 while (--len >= 0) {
566 (*jmpFct)(this, bci + tableswitch.dest_offset_at(len), data);
567 }
568 break;
569 }
570
571 case Bytecodes::_lookupswitch:
572 { Bytecode_lookupswitch lookupswitch(method(), bcs->bcp());
573 int npairs = lookupswitch.number_of_pairs();
574 (*jmpFct)(this, bci + lookupswitch.default_offset(), data); /* Default. */
575 while(--npairs >= 0) {
576 LookupswitchPair pair = lookupswitch.pair_at(npairs);
577 (*jmpFct)(this, bci + pair.offset(), data);
578 }
579 break;
580 }
581 case Bytecodes::_jsr:
582 assert(bcs->is_wide()==false, "sanity check");
583 (*jmpFct)(this, bcs->dest(), data);
584
585
586
587 break;
588 case Bytecodes::_jsr_w:
589 (*jmpFct)(this, bcs->dest_w(), data);
590 break;
591 case Bytecodes::_wide:
592 ShouldNotReachHere();
593 return true;
594 break;
595 case Bytecodes::_athrow:
596 case Bytecodes::_ireturn:
597 case Bytecodes::_lreturn:
598 case Bytecodes::_freturn:
599 case Bytecodes::_dreturn:
600 case Bytecodes::_areturn:
601 case Bytecodes::_return:
602 case Bytecodes::_ret:
603 break;
604 default:
605 return true;
606 }
607 return false;
608 }
609
610 /* Requires "pc" to be the head of a basic block; returns that basic
611 block. */
612 BasicBlock *GenerateOopMap::get_basic_block_at(int bci) const {
613 BasicBlock* bb = get_basic_block_containing(bci);
614 assert(bb->_bci == bci, "should have found BB");
615 return bb;
616 }
617
618 // Requires "pc" to be the start of an instruction; returns the basic
619 // block containing that instruction. */
620 BasicBlock *GenerateOopMap::get_basic_block_containing(int bci) const {
621 BasicBlock *bbs = _basic_blocks;
622 int lo = 0, hi = _bb_count - 1;
623
624 while (lo <= hi) {
625 int m = (lo + hi) / 2;
626 int mbci = bbs[m]._bci;
627 int nbci;
628
629 if ( m == _bb_count-1) {
630 assert( bci >= mbci && bci < method()->code_size(), "sanity check failed");
631 return bbs+m;
632 } else {
633 nbci = bbs[m+1]._bci;
634 }
635
636 if ( mbci <= bci && bci < nbci) {
637 return bbs+m;
638 } else if (mbci < bci) {
639 lo = m + 1;
640 } else {
641 assert(mbci > bci, "sanity check");
642 hi = m - 1;
643 }
644 }
645
646 fatal("should have found BB");
647 return NULL;
648 }
649
650 void GenerateOopMap::restore_state(BasicBlock *bb)
651 {
652 memcpy(_state, bb->_state, _state_len*sizeof(CellTypeState));
653 _stack_top = bb->_stack_top;
654 _monitor_top = bb->_monitor_top;
655 }
656
657 int GenerateOopMap::next_bb_start_pc(BasicBlock *bb) {
658 int bbNum = bb - _basic_blocks + 1;
659 if (bbNum == _bb_count)
660 return method()->code_size();
661
662 return _basic_blocks[bbNum]._bci;
663 }
664
665 //
666 // CellType handling methods
667 //
668
669 // Allocate memory and throw LinkageError if failure.
670 #define ALLOC_RESOURCE_ARRAY(var, type, count) \
671 var = NEW_RESOURCE_ARRAY_RETURN_NULL(type, count); \
672 if (var == NULL) { \
673 report_error("Cannot reserve enough memory to analyze this method"); \
674 return; \
675 }
676
677
678 void GenerateOopMap::init_state() {
679 _state_len = _max_locals + _max_stack + _max_monitors;
680 ALLOC_RESOURCE_ARRAY(_state, CellTypeState, _state_len);
681 memset(_state, 0, _state_len * sizeof(CellTypeState));
682 int count = MAX3(_max_locals, _max_stack, _max_monitors) + 1/*for null terminator char */;
683 ALLOC_RESOURCE_ARRAY(_state_vec_buf, char, count);
684 }
685
686 void GenerateOopMap::make_context_uninitialized() {
687 CellTypeState* vs = vars();
688
689 for (int i = 0; i < _max_locals; i++)
690 vs[i] = CellTypeState::uninit;
691
692 _stack_top = 0;
693 _monitor_top = 0;
694 }
695
696 int GenerateOopMap::methodsig_to_effect(Symbol* signature, bool is_static, CellTypeState* effect) {
697 ComputeEntryStack ces(signature);
698 return ces.compute_for_parameters(is_static, effect);
699 }
700
701 // Return result of merging cts1 and cts2.
702 CellTypeState CellTypeState::merge(CellTypeState cts, int slot) const {
703 CellTypeState result;
704
705 assert(!is_bottom() && !cts.is_bottom(),
706 "merge of bottom values is handled elsewhere");
707
708 result._state = _state | cts._state;
709
710 // If the top bit is set, we don't need to do any more work.
711 if (!result.is_info_top()) {
712 assert((result.can_be_address() || result.can_be_reference()),
713 "only addresses and references have non-top info");
714
715 if (!equal(cts)) {
716 // The two values being merged are different. Raise to top.
717 if (result.is_reference()) {
718 result = CellTypeState::make_slot_ref(slot);
719 } else {
720 result._state |= info_conflict;
721 }
722 }
723 }
724 assert(result.is_valid_state(), "checking that CTS merge maintains legal state");
725
726 return result;
727 }
728
729 // Merge the variable state for locals and stack from cts into bbts.
730 bool GenerateOopMap::merge_local_state_vectors(CellTypeState* cts,
731 CellTypeState* bbts) {
732 int i;
733 int len = _max_locals + _stack_top;
734 bool change = false;
735
736 for (i = len - 1; i >= 0; i--) {
737 CellTypeState v = cts[i].merge(bbts[i], i);
738 change = change || !v.equal(bbts[i]);
739 bbts[i] = v;
740 }
741
742 return change;
743 }
744
745 // Merge the monitor stack state from cts into bbts.
746 bool GenerateOopMap::merge_monitor_state_vectors(CellTypeState* cts,
747 CellTypeState* bbts) {
748 bool change = false;
749 if (_max_monitors > 0 && _monitor_top != bad_monitors) {
750 // If there are no monitors in the program, or there has been
751 // a monitor matching error before this point in the program,
752 // then we do not merge in the monitor state.
753
754 int base = _max_locals + _max_stack;
755 int len = base + _monitor_top;
756 for (int i = len - 1; i >= base; i--) {
757 CellTypeState v = cts[i].merge(bbts[i], i);
758
759 // Can we prove that, when there has been a change, it will already
760 // have been detected at this point? That would make this equal
761 // check here unnecessary.
762 change = change || !v.equal(bbts[i]);
763 bbts[i] = v;
764 }
765 }
766
767 return change;
768 }
769
770 void GenerateOopMap::copy_state(CellTypeState *dst, CellTypeState *src) {
771 int len = _max_locals + _stack_top;
772 for (int i = 0; i < len; i++) {
773 if (src[i].is_nonlock_reference()) {
774 dst[i] = CellTypeState::make_slot_ref(i);
775 } else {
776 dst[i] = src[i];
777 }
778 }
779 if (_max_monitors > 0 && _monitor_top != bad_monitors) {
780 int base = _max_locals + _max_stack;
781 len = base + _monitor_top;
782 for (int i = base; i < len; i++) {
783 dst[i] = src[i];
784 }
785 }
786 }
787
788
789 // Merge the states for the current block and the next. As long as a
790 // block is reachable the locals and stack must be merged. If the
791 // stack heights don't match then this is a verification error and
792 // it's impossible to interpret the code. Simultaneously monitor
793 // states are being check to see if they nest statically. If monitor
794 // depths match up then their states are merged. Otherwise the
795 // mismatch is simply recorded and interpretation continues since
796 // monitor matching is purely informational and doesn't say anything
797 // about the correctness of the code.
798 void GenerateOopMap::merge_state_into_bb(BasicBlock *bb) {
799 guarantee(bb != NULL, "null basicblock");
800 assert(bb->is_alive(), "merging state into a dead basicblock");
801
802 if (_stack_top == bb->_stack_top) {
803 // always merge local state even if monitors don't match.
804 if (merge_local_state_vectors(_state, bb->_state)) {
805 bb->set_changed(true);
806 }
807 if (_monitor_top == bb->_monitor_top) {
808 // monitors still match so continue merging monitor states.
809 if (merge_monitor_state_vectors(_state, bb->_state)) {
810 bb->set_changed(true);
811 }
812 } else {
813 if (log_is_enabled(Info, monitormismatch)) {
814 report_monitor_mismatch("monitor stack height merge conflict");
815 }
816 // When the monitor stacks are not matched, we set _monitor_top to
817 // bad_monitors. This signals that, from here on, the monitor stack cannot
818 // be trusted. In particular, monitorexit bytecodes may throw
819 // exceptions. We mark this block as changed so that the change
820 // propagates properly.
821 bb->_monitor_top = bad_monitors;
822 bb->set_changed(true);
823 _monitor_safe = false;
824 }
825 } else if (!bb->is_reachable()) {
826 // First time we look at this BB
827 copy_state(bb->_state, _state);
828 bb->_stack_top = _stack_top;
829 bb->_monitor_top = _monitor_top;
830 bb->set_changed(true);
831 } else {
832 verify_error("stack height conflict: %d vs. %d", _stack_top, bb->_stack_top);
833 }
834 }
835
836 void GenerateOopMap::merge_state(GenerateOopMap *gom, int bci, int* data) {
837 gom->merge_state_into_bb(gom->get_basic_block_at(bci));
838 }
839
840 void GenerateOopMap::set_var(int localNo, CellTypeState cts) {
841 assert(cts.is_reference() || cts.is_inline_type() || cts.is_address(),
842 "wrong celltypestate");
843 if (localNo < 0 || localNo > _max_locals) {
844 verify_error("variable write error: r%d", localNo);
845 return;
846 }
847 vars()[localNo] = cts;
848 }
849
850 CellTypeState GenerateOopMap::get_var(int localNo) {
851 assert(localNo < _max_locals + _nof_refval_conflicts, "variable read error");
852 if (localNo < 0 || localNo > _max_locals) {
853 verify_error("variable read error: r%d", localNo);
854 return valCTS; // just to pick something;
855 }
856 return vars()[localNo];
857 }
858
859 CellTypeState GenerateOopMap::pop() {
860 if ( _stack_top <= 0) {
861 verify_error("stack underflow");
862 return valCTS; // just to pick something
863 }
864 return stack()[--_stack_top];
865 }
866
867 void GenerateOopMap::push(CellTypeState cts) {
868 if ( _stack_top >= _max_stack) {
869 verify_error("stack overflow");
870 return;
871 }
872 stack()[_stack_top++] = cts;
873 }
874
875 CellTypeState GenerateOopMap::monitor_pop() {
876 assert(_monitor_top != bad_monitors, "monitor_pop called on error monitor stack");
877 if (_monitor_top == 0) {
878 // We have detected a pop of an empty monitor stack.
879 _monitor_safe = false;
880 _monitor_top = bad_monitors;
881
882 if (log_is_enabled(Info, monitormismatch)) {
883 report_monitor_mismatch("monitor stack underflow");
884 }
885 return CellTypeState::ref; // just to keep the analysis going.
886 }
887 return monitors()[--_monitor_top];
888 }
889
890 void GenerateOopMap::monitor_push(CellTypeState cts) {
891 assert(_monitor_top != bad_monitors, "monitor_push called on error monitor stack");
892 if (_monitor_top >= _max_monitors) {
893 // Some monitorenter is being executed more than once.
894 // This means that the monitor stack cannot be simulated.
895 _monitor_safe = false;
896 _monitor_top = bad_monitors;
897
898 if (log_is_enabled(Info, monitormismatch)) {
899 report_monitor_mismatch("monitor stack overflow");
900 }
901 return;
902 }
903 monitors()[_monitor_top++] = cts;
904 }
905
906 //
907 // Interpretation handling methods
908 //
909
910 void GenerateOopMap::do_interpretation()
911 {
912 // "i" is just for debugging, so we can detect cases where this loop is
913 // iterated more than once.
914 int i = 0;
915 do {
916 #ifndef PRODUCT
917 if (TraceNewOopMapGeneration) {
918 tty->print("\n\nIteration #%d of do_interpretation loop, method:\n", i);
919 method()->print_name(tty);
920 tty->print("\n\n");
921 }
922 #endif
923 _conflict = false;
924 _monitor_safe = true;
925 // init_state is now called from init_basic_blocks. The length of a
926 // state vector cannot be determined until we have made a pass through
927 // the bytecodes counting the possible monitor entries.
928 if (!_got_error) init_basic_blocks();
929 if (!_got_error) setup_method_entry_state();
930 if (!_got_error) interp_all();
931 if (!_got_error) rewrite_refval_conflicts();
932 i++;
933 } while (_conflict && !_got_error);
934 }
935
936 void GenerateOopMap::init_basic_blocks() {
937 // Note: Could consider reserving only the needed space for each BB's state
938 // (entry stack may not be of maximal height for every basic block).
939 // But cumbersome since we don't know the stack heights yet. (Nor the
940 // monitor stack heights...)
941
942 ALLOC_RESOURCE_ARRAY(_basic_blocks, BasicBlock, _bb_count);
943
944 // Make a pass through the bytecodes. Count the number of monitorenters.
945 // This can be used an upper bound on the monitor stack depth in programs
946 // which obey stack discipline with their monitor usage. Initialize the
947 // known information about basic blocks.
948 BytecodeStream j(_method);
949 Bytecodes::Code bytecode;
950
951 int bbNo = 0;
952 int monitor_count = 0;
953 int prev_bci = -1;
954 while( (bytecode = j.next()) >= 0) {
955 if (j.code() == Bytecodes::_monitorenter) {
956 monitor_count++;
957 }
958
959 int bci = j.bci();
960 if (is_bb_header(bci)) {
961 // Initialize the basicblock structure
962 BasicBlock *bb = _basic_blocks + bbNo;
963 bb->_bci = bci;
964 bb->_max_locals = _max_locals;
965 bb->_max_stack = _max_stack;
966 bb->set_changed(false);
967 bb->_stack_top = BasicBlock::_dead_basic_block; // Initialize all basicblocks are dead.
968 bb->_monitor_top = bad_monitors;
969
970 if (bbNo > 0) {
971 _basic_blocks[bbNo - 1]._end_bci = prev_bci;
972 }
973
974 bbNo++;
975 }
976 // Remember prevous bci.
977 prev_bci = bci;
978 }
979 // Set
980 _basic_blocks[bbNo-1]._end_bci = prev_bci;
981
982
983 // Check that the correct number of basicblocks was found
984 if (bbNo !=_bb_count) {
985 if (bbNo < _bb_count) {
986 verify_error("jump into the middle of instruction?");
987 return;
988 } else {
989 verify_error("extra basic blocks - should not happen?");
990 return;
991 }
992 }
993
994 _max_monitors = monitor_count;
995
996 // Now that we have a bound on the depth of the monitor stack, we can
997 // initialize the CellTypeState-related information.
998 init_state();
999
1000 // We allocate space for all state-vectors for all basicblocks in one huge
1001 // chunk. Then in the next part of the code, we set a pointer in each
1002 // _basic_block that points to each piece.
1003
1004 // The product of bbNo and _state_len can get large if there are lots of
1005 // basic blocks and stack/locals/monitors. Need to check to make sure
1006 // we don't overflow the capacity of a pointer.
1007 if ((unsigned)bbNo > UINTPTR_MAX / sizeof(CellTypeState) / _state_len) {
1008 report_error("The amount of memory required to analyze this method "
1009 "exceeds addressable range");
1010 return;
1011 }
1012
1013 CellTypeState *basicBlockState;
1014 ALLOC_RESOURCE_ARRAY(basicBlockState, CellTypeState, bbNo * _state_len);
1015 memset(basicBlockState, 0, bbNo * _state_len * sizeof(CellTypeState));
1016
1017 // Make a pass over the basicblocks and assign their state vectors.
1018 for (int blockNum=0; blockNum < bbNo; blockNum++) {
1019 BasicBlock *bb = _basic_blocks + blockNum;
1020 bb->_state = basicBlockState + blockNum * _state_len;
1021
1022 #ifdef ASSERT
1023 if (blockNum + 1 < bbNo) {
1024 address bcp = _method->bcp_from(bb->_end_bci);
1025 int bc_len = Bytecodes::java_length_at(_method(), bcp);
1026 assert(bb->_end_bci + bc_len == bb[1]._bci, "unmatched bci info in basicblock");
1027 }
1028 #endif
1029 }
1030 #ifdef ASSERT
1031 { BasicBlock *bb = &_basic_blocks[bbNo-1];
1032 address bcp = _method->bcp_from(bb->_end_bci);
1033 int bc_len = Bytecodes::java_length_at(_method(), bcp);
1034 assert(bb->_end_bci + bc_len == _method->code_size(), "wrong end bci");
1035 }
1036 #endif
1037
1038 // Mark all alive blocks
1039 mark_reachable_code();
1040 }
1041
1042 void GenerateOopMap::setup_method_entry_state() {
1043
1044 // Initialize all locals to 'uninit' and set stack-height to 0
1045 make_context_uninitialized();
1046
1047 // Initialize CellState type of arguments
1048 methodsig_to_effect(method()->signature(), method()->is_static(), vars());
1049
1050 // If some references must be pre-assigned to null, then set that up
1051 initialize_vars();
1052
1053 // This is the start state
1054 merge_state_into_bb(&_basic_blocks[0]);
1055
1056 assert(_basic_blocks[0].changed(), "we are not getting off the ground");
1057 }
1058
1059 // The instruction at bci is changing size by "delta". Update the basic blocks.
1060 void GenerateOopMap::update_basic_blocks(int bci, int delta,
1061 int new_method_size) {
1062 assert(new_method_size >= method()->code_size() + delta,
1063 "new method size is too small");
1064
1065 _bb_hdr_bits.reinitialize(new_method_size);
1066
1067 for(int k = 0; k < _bb_count; k++) {
1068 if (_basic_blocks[k]._bci > bci) {
1069 _basic_blocks[k]._bci += delta;
1070 _basic_blocks[k]._end_bci += delta;
1071 }
1072 _bb_hdr_bits.at_put(_basic_blocks[k]._bci, true);
1073 }
1074 }
1075
1076 //
1077 // Initvars handling
1078 //
1079
1080 void GenerateOopMap::initialize_vars() {
1081 for (int k = 0; k < _init_vars->length(); k++)
1082 _state[_init_vars->at(k)] = CellTypeState::make_slot_ref(k);
1083 }
1084
1085 void GenerateOopMap::add_to_ref_init_set(int localNo) {
1086
1087 if (TraceNewOopMapGeneration)
1088 tty->print_cr("Added init vars: %d", localNo);
1089
1090 // Is it already in the set?
1091 if (_init_vars->contains(localNo) )
1092 return;
1093
1094 _init_vars->append(localNo);
1095 }
1096
1097 //
1098 // Interpreration code
1099 //
1100
1101 void GenerateOopMap::interp_all() {
1102 bool change = true;
1103
1104 while (change && !_got_error) {
1105 change = false;
1106 for (int i = 0; i < _bb_count && !_got_error; i++) {
1107 BasicBlock *bb = &_basic_blocks[i];
1108 if (bb->changed()) {
1109 if (_got_error) return;
1110 change = true;
1111 bb->set_changed(false);
1112 interp_bb(bb);
1113 }
1114 }
1115 }
1116 }
1117
1118 void GenerateOopMap::interp_bb(BasicBlock *bb) {
1119
1120 // We do not want to do anything in case the basic-block has not been initialized. This
1121 // will happen in the case where there is dead-code hang around in a method.
1122 assert(bb->is_reachable(), "should be reachable or deadcode exist");
1123 restore_state(bb);
1124
1125 BytecodeStream itr(_method);
1126
1127 // Set iterator interval to be the current basicblock
1128 int lim_bci = next_bb_start_pc(bb);
1129 itr.set_interval(bb->_bci, lim_bci);
1130 assert(lim_bci != bb->_bci, "must be at least one instruction in a basicblock");
1131 itr.next(); // read first instruction
1132
1133 // Iterates through all bytecodes except the last in a basic block.
1134 // We handle the last one special, since there is controlflow change.
1135 while(itr.next_bci() < lim_bci && !_got_error) {
1136 if (_has_exceptions || _monitor_top != 0) {
1137 // We do not need to interpret the results of exceptional
1138 // continuation from this instruction when the method has no
1139 // exception handlers and the monitor stack is currently
1140 // empty.
1141 do_exception_edge(&itr);
1142 }
1143 interp1(&itr);
1144 itr.next();
1145 }
1146
1147 // Handle last instruction.
1148 if (!_got_error) {
1149 assert(itr.next_bci() == lim_bci, "must point to end");
1150 if (_has_exceptions || _monitor_top != 0) {
1151 do_exception_edge(&itr);
1152 }
1153 interp1(&itr);
1154
1155 bool fall_through = jump_targets_do(&itr, GenerateOopMap::merge_state, NULL);
1156 if (_got_error) return;
1157
1158 if (itr.code() == Bytecodes::_ret) {
1159 assert(!fall_through, "cannot be set if ret instruction");
1160 // Automatically handles 'wide' ret indicies
1161 ret_jump_targets_do(&itr, GenerateOopMap::merge_state, itr.get_index(), NULL);
1162 } else if (fall_through) {
1163 // Hit end of BB, but the instr. was a fall-through instruction,
1164 // so perform transition as if the BB ended in a "jump".
1165 if (lim_bci != bb[1]._bci) {
1166 verify_error("bytecodes fell through last instruction");
1167 return;
1168 }
1169 merge_state_into_bb(bb + 1);
1170 }
1171 }
1172 }
1173
1174 void GenerateOopMap::do_exception_edge(BytecodeStream* itr) {
1175 // Only check exception edge, if bytecode can trap
1176 if (!Bytecodes::can_trap(itr->code())) return;
1177 switch (itr->code()) {
1178 case Bytecodes::_aload_0:
1179 // These bytecodes can trap for rewriting. We need to assume that
1180 // they do not throw exceptions to make the monitor analysis work.
1181 return;
1182
1183 case Bytecodes::_ireturn:
1184 case Bytecodes::_lreturn:
1185 case Bytecodes::_freturn:
1186 case Bytecodes::_dreturn:
1187 case Bytecodes::_areturn:
1188 case Bytecodes::_return:
1189 // If the monitor stack height is not zero when we leave the method,
1190 // then we are either exiting with a non-empty stack or we have
1191 // found monitor trouble earlier in our analysis. In either case,
1192 // assume an exception could be taken here.
1193 if (_monitor_top == 0) {
1194 return;
1195 }
1196 break;
1197
1198 case Bytecodes::_monitorexit:
1199 // If the monitor stack height is bad_monitors, then we have detected a
1200 // monitor matching problem earlier in the analysis. If the
1201 // monitor stack height is 0, we are about to pop a monitor
1202 // off of an empty stack. In either case, the bytecode
1203 // could throw an exception.
1204 if (_monitor_top != bad_monitors && _monitor_top != 0) {
1205 return;
1206 }
1207 break;
1208
1209 default:
1210 break;
1211 }
1212
1213 if (_has_exceptions) {
1214 int bci = itr->bci();
1215 ExceptionTable exct(method());
1216 for(int i = 0; i< exct.length(); i++) {
1217 int start_pc = exct.start_pc(i);
1218 int end_pc = exct.end_pc(i);
1219 int handler_pc = exct.handler_pc(i);
1220 int catch_type = exct.catch_type_index(i);
1221
1222 if (start_pc <= bci && bci < end_pc) {
1223 BasicBlock *excBB = get_basic_block_at(handler_pc);
1224 guarantee(excBB != NULL, "no basic block for exception");
1225 CellTypeState *excStk = excBB->stack();
1226 CellTypeState *cOpStck = stack();
1227 CellTypeState cOpStck_0 = cOpStck[0];
1228 int cOpStackTop = _stack_top;
1229
1230 // Exception stacks are always the same.
1231 assert(method()->max_stack() > 0, "sanity check");
1232
1233 // We remembered the size and first element of "cOpStck"
1234 // above; now we temporarily set them to the appropriate
1235 // values for an exception handler. */
1236 cOpStck[0] = CellTypeState::make_slot_ref(_max_locals);
1237 _stack_top = 1;
1238
1239 merge_state_into_bb(excBB);
1240
1241 // Now undo the temporary change.
1242 cOpStck[0] = cOpStck_0;
1243 _stack_top = cOpStackTop;
1244
1245 // If this is a "catch all" handler, then we do not need to
1246 // consider any additional handlers.
1247 if (catch_type == 0) {
1248 return;
1249 }
1250 }
1251 }
1252 }
1253
1254 // It is possible that none of the exception handlers would have caught
1255 // the exception. In this case, we will exit the method. We must
1256 // ensure that the monitor stack is empty in this case.
1257 if (_monitor_top == 0) {
1258 return;
1259 }
1260
1261 // We pessimistically assume that this exception can escape the
1262 // method. (It is possible that it will always be caught, but
1263 // we don't care to analyse the types of the catch clauses.)
1264
1265 // We don't set _monitor_top to bad_monitors because there are no successors
1266 // to this exceptional exit.
1267
1268 if (log_is_enabled(Info, monitormismatch) && _monitor_safe) {
1269 // We check _monitor_safe so that we only report the first mismatched
1270 // exceptional exit.
1271 report_monitor_mismatch("non-empty monitor stack at exceptional exit");
1272 }
1273 _monitor_safe = false;
1274
1275 }
1276
1277 void GenerateOopMap::report_monitor_mismatch(const char *msg) {
1278 ResourceMark rm;
1279 LogStream ls(Log(monitormismatch)::info());
1280 ls.print("Monitor mismatch in method ");
1281 method()->print_short_name(&ls);
1282 ls.print_cr(": %s", msg);
1283 }
1284
1285 void GenerateOopMap::print_states(outputStream *os,
1286 CellTypeState* vec, int num) {
1287 for (int i = 0; i < num; i++) {
1288 vec[i].print(tty);
1289 }
1290 }
1291
1292 // Print the state values at the current bytecode.
1293 void GenerateOopMap::print_current_state(outputStream *os,
1294 BytecodeStream *currentBC,
1295 bool detailed) {
1296 if (detailed) {
1297 os->print(" %4d vars = ", currentBC->bci());
1298 print_states(os, vars(), _max_locals);
1299 os->print(" %s", Bytecodes::name(currentBC->code()));
1300 } else {
1301 os->print(" %4d vars = '%s' ", currentBC->bci(), state_vec_to_string(vars(), _max_locals));
1302 os->print(" stack = '%s' ", state_vec_to_string(stack(), _stack_top));
1303 if (_monitor_top != bad_monitors) {
1304 os->print(" monitors = '%s' \t%s", state_vec_to_string(monitors(), _monitor_top), Bytecodes::name(currentBC->code()));
1305 } else {
1306 os->print(" [bad monitor stack]");
1307 }
1308 }
1309
1310 switch(currentBC->code()) {
1311 case Bytecodes::_invokevirtual:
1312 case Bytecodes::_invokespecial:
1313 case Bytecodes::_invokestatic:
1314 case Bytecodes::_invokedynamic:
1315 case Bytecodes::_invokeinterface: {
1316 int idx = currentBC->has_index_u4() ? currentBC->get_index_u4() : currentBC->get_index_u2_cpcache();
1317 ConstantPool* cp = method()->constants();
1318 int nameAndTypeIdx = cp->name_and_type_ref_index_at(idx);
1319 int signatureIdx = cp->signature_ref_index_at(nameAndTypeIdx);
1320 Symbol* signature = cp->symbol_at(signatureIdx);
1321 os->print("%s", signature->as_C_string());
1322 }
1323 default:
1324 break;
1325 }
1326
1327 if (detailed) {
1328 os->cr();
1329 os->print(" stack = ");
1330 print_states(os, stack(), _stack_top);
1331 os->cr();
1332 if (_monitor_top != bad_monitors) {
1333 os->print(" monitors = ");
1334 print_states(os, monitors(), _monitor_top);
1335 } else {
1336 os->print(" [bad monitor stack]");
1337 }
1338 }
1339
1340 os->cr();
1341 }
1342
1343 // Sets the current state to be the state after executing the
1344 // current instruction, starting in the current state.
1345 void GenerateOopMap::interp1(BytecodeStream *itr) {
1346 if (TraceNewOopMapGeneration) {
1347 print_current_state(tty, itr, TraceNewOopMapGenerationDetailed);
1348 }
1349
1350 // Should we report the results? Result is reported *before* the instruction at the current bci is executed.
1351 // However, not for calls. For calls we do not want to include the arguments, so we postpone the reporting until
1352 // they have been popped (in method ppl).
1353 if (_report_result == true) {
1354 switch(itr->code()) {
1355 case Bytecodes::_invokevirtual:
1356 case Bytecodes::_invokespecial:
1357 case Bytecodes::_invokestatic:
1358 case Bytecodes::_invokedynamic:
1359 case Bytecodes::_invokeinterface:
1360 _itr_send = itr;
1361 _report_result_for_send = true;
1362 break;
1363 default:
1364 fill_stackmap_for_opcodes(itr, vars(), stack(), _stack_top);
1365 break;
1366 }
1367 }
1368
1369 // abstract interpretation of current opcode
1370 switch(itr->code()) {
1371 case Bytecodes::_nop: break;
1372 case Bytecodes::_goto: break;
1373 case Bytecodes::_goto_w: break;
1374 case Bytecodes::_iinc: break;
1375 case Bytecodes::_return: do_return_monitor_check();
1376 break;
1377
1378 case Bytecodes::_aconst_null:
1379 case Bytecodes::_new: ppush1(CellTypeState::make_line_ref(itr->bci()));
1380 break;
1381
1382 case Bytecodes::_defaultvalue: ppush1(CellTypeState::make_line_ref(itr->bci())); break;
1383 case Bytecodes::_withfield: do_withfield(itr->get_index_u2_cpcache(), itr->bci()); break;
1384
1385 case Bytecodes::_iconst_m1:
1386 case Bytecodes::_iconst_0:
1387 case Bytecodes::_iconst_1:
1388 case Bytecodes::_iconst_2:
1389 case Bytecodes::_iconst_3:
1390 case Bytecodes::_iconst_4:
1391 case Bytecodes::_iconst_5:
1392 case Bytecodes::_fconst_0:
1393 case Bytecodes::_fconst_1:
1394 case Bytecodes::_fconst_2:
1395 case Bytecodes::_bipush:
1396 case Bytecodes::_sipush: ppush1(valCTS); break;
1397
1398 case Bytecodes::_lconst_0:
1399 case Bytecodes::_lconst_1:
1400 case Bytecodes::_dconst_0:
1401 case Bytecodes::_dconst_1: ppush(vvCTS); break;
1402
1403 case Bytecodes::_ldc2_w: ppush(vvCTS); break;
1404
1405 case Bytecodes::_ldc: // fall through:
1406 case Bytecodes::_ldc_w: do_ldc(itr->bci()); break;
1407
1408 case Bytecodes::_iload:
1409 case Bytecodes::_fload: ppload(vCTS, itr->get_index()); break;
1410
1411 case Bytecodes::_lload:
1412 case Bytecodes::_dload: ppload(vvCTS,itr->get_index()); break;
1413
1414 case Bytecodes::_aload: ppload(rCTS, itr->get_index()); break;
1415
1416 case Bytecodes::_iload_0:
1417 case Bytecodes::_fload_0: ppload(vCTS, 0); break;
1418 case Bytecodes::_iload_1:
1419 case Bytecodes::_fload_1: ppload(vCTS, 1); break;
1420 case Bytecodes::_iload_2:
1421 case Bytecodes::_fload_2: ppload(vCTS, 2); break;
1422 case Bytecodes::_iload_3:
1423 case Bytecodes::_fload_3: ppload(vCTS, 3); break;
1424
1425 case Bytecodes::_lload_0:
1426 case Bytecodes::_dload_0: ppload(vvCTS, 0); break;
1427 case Bytecodes::_lload_1:
1428 case Bytecodes::_dload_1: ppload(vvCTS, 1); break;
1429 case Bytecodes::_lload_2:
1430 case Bytecodes::_dload_2: ppload(vvCTS, 2); break;
1431 case Bytecodes::_lload_3:
1432 case Bytecodes::_dload_3: ppload(vvCTS, 3); break;
1433
1434 case Bytecodes::_aload_0: ppload(rCTS, 0); break;
1435 case Bytecodes::_aload_1: ppload(rCTS, 1); break;
1436 case Bytecodes::_aload_2: ppload(rCTS, 2); break;
1437 case Bytecodes::_aload_3: ppload(rCTS, 3); break;
1438
1439 case Bytecodes::_iaload:
1440 case Bytecodes::_faload:
1441 case Bytecodes::_baload:
1442 case Bytecodes::_caload:
1443 case Bytecodes::_saload: pp(vrCTS, vCTS); break;
1444
1445 case Bytecodes::_laload: pp(vrCTS, vvCTS); break;
1446 case Bytecodes::_daload: pp(vrCTS, vvCTS); break;
1447
1448 case Bytecodes::_aaload: pp_new_ref(vrCTS, itr->bci()); break;
1449
1450 case Bytecodes::_istore:
1451 case Bytecodes::_fstore: ppstore(vCTS, itr->get_index()); break;
1452
1453 case Bytecodes::_lstore:
1454 case Bytecodes::_dstore: ppstore(vvCTS, itr->get_index()); break;
1455
1456 case Bytecodes::_astore: do_astore(itr->get_index()); break;
1457
1458 case Bytecodes::_istore_0:
1459 case Bytecodes::_fstore_0: ppstore(vCTS, 0); break;
1460 case Bytecodes::_istore_1:
1461 case Bytecodes::_fstore_1: ppstore(vCTS, 1); break;
1462 case Bytecodes::_istore_2:
1463 case Bytecodes::_fstore_2: ppstore(vCTS, 2); break;
1464 case Bytecodes::_istore_3:
1465 case Bytecodes::_fstore_3: ppstore(vCTS, 3); break;
1466
1467 case Bytecodes::_lstore_0:
1468 case Bytecodes::_dstore_0: ppstore(vvCTS, 0); break;
1469 case Bytecodes::_lstore_1:
1470 case Bytecodes::_dstore_1: ppstore(vvCTS, 1); break;
1471 case Bytecodes::_lstore_2:
1472 case Bytecodes::_dstore_2: ppstore(vvCTS, 2); break;
1473 case Bytecodes::_lstore_3:
1474 case Bytecodes::_dstore_3: ppstore(vvCTS, 3); break;
1475
1476 case Bytecodes::_astore_0: do_astore(0); break;
1477 case Bytecodes::_astore_1: do_astore(1); break;
1478 case Bytecodes::_astore_2: do_astore(2); break;
1479 case Bytecodes::_astore_3: do_astore(3); break;
1480
1481 case Bytecodes::_iastore:
1482 case Bytecodes::_fastore:
1483 case Bytecodes::_bastore:
1484 case Bytecodes::_castore:
1485 case Bytecodes::_sastore: ppop(vvrCTS); break;
1486 case Bytecodes::_lastore:
1487 case Bytecodes::_dastore: ppop(vvvrCTS); break;
1488 case Bytecodes::_aastore: ppop(rvrCTS); break;
1489
1490 case Bytecodes::_pop: ppop_any(1); break;
1491 case Bytecodes::_pop2: ppop_any(2); break;
1492
1493 case Bytecodes::_dup: ppdupswap(1, "11"); break;
1494 case Bytecodes::_dup_x1: ppdupswap(2, "121"); break;
1495 case Bytecodes::_dup_x2: ppdupswap(3, "1321"); break;
1496 case Bytecodes::_dup2: ppdupswap(2, "2121"); break;
1497 case Bytecodes::_dup2_x1: ppdupswap(3, "21321"); break;
1498 case Bytecodes::_dup2_x2: ppdupswap(4, "214321"); break;
1499 case Bytecodes::_swap: ppdupswap(2, "12"); break;
1500
1501 case Bytecodes::_iadd:
1502 case Bytecodes::_fadd:
1503 case Bytecodes::_isub:
1504 case Bytecodes::_fsub:
1505 case Bytecodes::_imul:
1506 case Bytecodes::_fmul:
1507 case Bytecodes::_idiv:
1508 case Bytecodes::_fdiv:
1509 case Bytecodes::_irem:
1510 case Bytecodes::_frem:
1511 case Bytecodes::_ishl:
1512 case Bytecodes::_ishr:
1513 case Bytecodes::_iushr:
1514 case Bytecodes::_iand:
1515 case Bytecodes::_ior:
1516 case Bytecodes::_ixor:
1517 case Bytecodes::_l2f:
1518 case Bytecodes::_l2i:
1519 case Bytecodes::_d2f:
1520 case Bytecodes::_d2i:
1521 case Bytecodes::_fcmpl:
1522 case Bytecodes::_fcmpg: pp(vvCTS, vCTS); break;
1523
1524 case Bytecodes::_ladd:
1525 case Bytecodes::_dadd:
1526 case Bytecodes::_lsub:
1527 case Bytecodes::_dsub:
1528 case Bytecodes::_lmul:
1529 case Bytecodes::_dmul:
1530 case Bytecodes::_ldiv:
1531 case Bytecodes::_ddiv:
1532 case Bytecodes::_lrem:
1533 case Bytecodes::_drem:
1534 case Bytecodes::_land:
1535 case Bytecodes::_lor:
1536 case Bytecodes::_lxor: pp(vvvvCTS, vvCTS); break;
1537
1538 case Bytecodes::_ineg:
1539 case Bytecodes::_fneg:
1540 case Bytecodes::_i2f:
1541 case Bytecodes::_f2i:
1542 case Bytecodes::_i2c:
1543 case Bytecodes::_i2s:
1544 case Bytecodes::_i2b: pp(vCTS, vCTS); break;
1545
1546 case Bytecodes::_lneg:
1547 case Bytecodes::_dneg:
1548 case Bytecodes::_l2d:
1549 case Bytecodes::_d2l: pp(vvCTS, vvCTS); break;
1550
1551 case Bytecodes::_lshl:
1552 case Bytecodes::_lshr:
1553 case Bytecodes::_lushr: pp(vvvCTS, vvCTS); break;
1554
1555 case Bytecodes::_i2l:
1556 case Bytecodes::_i2d:
1557 case Bytecodes::_f2l:
1558 case Bytecodes::_f2d: pp(vCTS, vvCTS); break;
1559
1560 case Bytecodes::_lcmp: pp(vvvvCTS, vCTS); break;
1561 case Bytecodes::_dcmpl:
1562 case Bytecodes::_dcmpg: pp(vvvvCTS, vCTS); break;
1563
1564 case Bytecodes::_ifeq:
1565 case Bytecodes::_ifne:
1566 case Bytecodes::_iflt:
1567 case Bytecodes::_ifge:
1568 case Bytecodes::_ifgt:
1569 case Bytecodes::_ifle:
1570 case Bytecodes::_tableswitch: ppop1(valCTS);
1571 break;
1572 case Bytecodes::_ireturn:
1573 case Bytecodes::_freturn: do_return_monitor_check();
1574 ppop1(valCTS);
1575 break;
1576 case Bytecodes::_if_icmpeq:
1577 case Bytecodes::_if_icmpne:
1578 case Bytecodes::_if_icmplt:
1579 case Bytecodes::_if_icmpge:
1580 case Bytecodes::_if_icmpgt:
1581 case Bytecodes::_if_icmple: ppop(vvCTS);
1582 break;
1583
1584 case Bytecodes::_lreturn: do_return_monitor_check();
1585 ppop(vvCTS);
1586 break;
1587
1588 case Bytecodes::_dreturn: do_return_monitor_check();
1589 ppop(vvCTS);
1590 break;
1591
1592 case Bytecodes::_if_acmpeq:
1593 case Bytecodes::_if_acmpne: ppop(rrCTS); break;
1594
1595 case Bytecodes::_jsr: do_jsr(itr->dest()); break;
1596 case Bytecodes::_jsr_w: do_jsr(itr->dest_w()); break;
1597
1598 case Bytecodes::_getstatic: do_field(true, true, itr->get_index_u2_cpcache(), itr->bci()); break;
1599 case Bytecodes::_putstatic: do_field(false, true, itr->get_index_u2_cpcache(), itr->bci()); break;
1600 case Bytecodes::_getfield: do_field(true, false, itr->get_index_u2_cpcache(), itr->bci()); break;
1601 case Bytecodes::_putfield: do_field(false, false, itr->get_index_u2_cpcache(), itr->bci()); break;
1602
1603 case Bytecodes::_invokeinterface:
1604 case Bytecodes::_invokevirtual:
1605 case Bytecodes::_invokespecial: do_method(false, itr->get_index_u2_cpcache(), itr->bci()); break;
1606 case Bytecodes::_invokestatic: do_method(true , itr->get_index_u2_cpcache(), itr->bci()); break;
1607 case Bytecodes::_invokedynamic: do_method(true , itr->get_index_u4(), itr->bci()); break;
1608 case Bytecodes::_newarray:
1609 case Bytecodes::_anewarray: pp_new_ref(vCTS, itr->bci()); break;
1610 case Bytecodes::_checkcast: do_checkcast(); break;
1611 case Bytecodes::_arraylength:
1612 case Bytecodes::_instanceof: pp(rCTS, vCTS); break;
1613 case Bytecodes::_monitorenter: do_monitorenter(itr->bci()); break;
1614 case Bytecodes::_monitorexit: do_monitorexit(itr->bci()); break;
1615
1616 case Bytecodes::_athrow: // handled by do_exception_edge() BUT ...
1617 // vlh(apple): do_exception_edge() does not get
1618 // called if method has no exception handlers
1619 if ((!_has_exceptions) && (_monitor_top > 0)) {
1620 _monitor_safe = false;
1621 }
1622 break;
1623
1624 case Bytecodes::_areturn: do_return_monitor_check();
1625 ppop1(refCTS);
1626 break;
1627
1628 case Bytecodes::_ifnull:
1629 case Bytecodes::_ifnonnull: ppop1(refCTS); break;
1630 case Bytecodes::_multianewarray: do_multianewarray(*(itr->bcp()+3), itr->bci()); break;
1631
1632 case Bytecodes::_wide: fatal("Iterator should skip this bytecode"); break;
1633 case Bytecodes::_ret: break;
1634
1635 // Java opcodes
1636 case Bytecodes::_lookupswitch: ppop1(valCTS); break;
1637
1638 default:
1639 tty->print("unexpected opcode: %d\n", itr->code());
1640 ShouldNotReachHere();
1641 break;
1642 }
1643 }
1644
1645 void GenerateOopMap::check_type(CellTypeState expected, CellTypeState actual) {
1646 if (!expected.equal_kind(actual)) {
1647 verify_error("wrong type on stack (found: %c expected: %c)", actual.to_char(), expected.to_char());
1648 }
1649 }
1650
1651 void GenerateOopMap::ppstore(CellTypeState *in, int loc_no) {
1652 while(!(*in).is_bottom()) {
1653 CellTypeState expected =*in++;
1654 CellTypeState actual = pop();
1655 check_type(expected, actual);
1656 assert(loc_no >= 0, "sanity check");
1657 set_var(loc_no++, actual);
1658 }
1659 }
1660
1661 void GenerateOopMap::ppload(CellTypeState *out, int loc_no) {
1662 while(!(*out).is_bottom()) {
1663 CellTypeState out1 = *out++;
1664 CellTypeState vcts = get_var(loc_no);
1665 assert(out1.can_be_reference() || out1.can_be_value(),
1666 "can only load refs. and values.");
1667 if (out1.is_reference()) {
1668 assert(loc_no>=0, "sanity check");
1669 if (!vcts.is_reference()) {
1670 // We were asked to push a reference, but the type of the
1671 // variable can be something else
1672 _conflict = true;
1673 if (vcts.can_be_uninit()) {
1674 // It is a ref-uninit conflict (at least). If there are other
1675 // problems, we'll get them in the next round
1676 add_to_ref_init_set(loc_no);
1677 vcts = out1;
1678 } else {
1679 // It wasn't a ref-uninit conflict. So must be a
1680 // ref-val or ref-pc conflict. Split the variable.
1681 record_refval_conflict(loc_no);
1682 vcts = out1;
1683 }
1684 push(out1); // recover...
1685 } else {
1686 push(vcts); // preserve reference.
1687 }
1688 // Otherwise it is a conflict, but one that verification would
1689 // have caught if illegal. In particular, it can't be a topCTS
1690 // resulting from mergeing two difference pcCTS's since the verifier
1691 // would have rejected any use of such a merge.
1692 } else {
1693 push(out1); // handle val/init conflict
1694 }
1695 loc_no++;
1696 }
1697 }
1698
1699 void GenerateOopMap::ppdupswap(int poplen, const char *out) {
1700 CellTypeState actual[5];
1701 assert(poplen < 5, "this must be less than length of actual vector");
1702
1703 // Pop all arguments.
1704 for (int i = 0; i < poplen; i++) {
1705 actual[i] = pop();
1706 }
1707 // Field _state is uninitialized when calling push.
1708 for (int i = poplen; i < 5; i++) {
1709 actual[i] = CellTypeState::uninit;
1710 }
1711
1712 // put them back
1713 char push_ch = *out++;
1714 while (push_ch != '\0') {
1715 int idx = push_ch - '1';
1716 assert(idx >= 0 && idx < poplen, "wrong arguments");
1717 push(actual[idx]);
1718 push_ch = *out++;
1719 }
1720 }
1721
1722 void GenerateOopMap::ppop1(CellTypeState out) {
1723 CellTypeState actual = pop();
1724 check_type(out, actual);
1725 }
1726
1727 void GenerateOopMap::ppop(CellTypeState *out) {
1728 while (!(*out).is_bottom()) {
1729 ppop1(*out++);
1730 }
1731 }
1732
1733 void GenerateOopMap::ppush1(CellTypeState in) {
1734 assert(in.is_reference() || in.is_inline_type(), "sanity check");
1735 push(in);
1736 }
1737
1738 void GenerateOopMap::ppush(CellTypeState *in) {
1739 while (!(*in).is_bottom()) {
1740 ppush1(*in++);
1741 }
1742 }
1743
1744 void GenerateOopMap::pp(CellTypeState *in, CellTypeState *out) {
1745 ppop(in);
1746 ppush(out);
1747 }
1748
1749 void GenerateOopMap::pp_new_ref(CellTypeState *in, int bci) {
1750 ppop(in);
1751 ppush1(CellTypeState::make_line_ref(bci));
1752 }
1753
1754 void GenerateOopMap::ppop_any(int poplen) {
1755 if (_stack_top >= poplen) {
1756 _stack_top -= poplen;
1757 } else {
1758 verify_error("stack underflow");
1759 }
1760 }
1761
1762 // Replace all occurences of the state 'match' with the state 'replace'
1763 // in our current state vector.
1764 void GenerateOopMap::replace_all_CTS_matches(CellTypeState match,
1765 CellTypeState replace) {
1766 int i;
1767 int len = _max_locals + _stack_top;
1768 bool change = false;
1769
1770 for (i = len - 1; i >= 0; i--) {
1771 if (match.equal(_state[i])) {
1772 _state[i] = replace;
1773 }
1774 }
1775
1776 if (_monitor_top > 0) {
1777 int base = _max_locals + _max_stack;
1778 len = base + _monitor_top;
1779 for (i = len - 1; i >= base; i--) {
1780 if (match.equal(_state[i])) {
1781 _state[i] = replace;
1782 }
1783 }
1784 }
1785 }
1786
1787 void GenerateOopMap::do_checkcast() {
1788 CellTypeState actual = pop();
1789 check_type(refCTS, actual);
1790 push(actual);
1791 }
1792
1793 void GenerateOopMap::do_monitorenter(int bci) {
1794 CellTypeState actual = pop();
1795 if (_monitor_top == bad_monitors) {
1796 return;
1797 }
1798
1799 // Bail out when we get repeated locks on an identical monitor. This case
1800 // isn't too hard to handle and can be made to work if supporting nested
1801 // redundant synchronized statements becomes a priority.
1802 //
1803 // See also "Note" in do_monitorexit(), below.
1804 if (actual.is_lock_reference()) {
1805 _monitor_top = bad_monitors;
1806 _monitor_safe = false;
1807
1808 if (log_is_enabled(Info, monitormismatch)) {
1809 report_monitor_mismatch("nested redundant lock -- bailout...");
1810 }
1811 return;
1812 }
1813
1814 CellTypeState lock = CellTypeState::make_lock_ref(bci);
1815 check_type(refCTS, actual);
1816 if (!actual.is_info_top()) {
1817 replace_all_CTS_matches(actual, lock);
1818 monitor_push(lock);
1819 }
1820 }
1821
1822 void GenerateOopMap::do_monitorexit(int bci) {
1823 CellTypeState actual = pop();
1824 if (_monitor_top == bad_monitors) {
1825 return;
1826 }
1827 check_type(refCTS, actual);
1828 CellTypeState expected = monitor_pop();
1829 if (!actual.is_lock_reference() || !expected.equal(actual)) {
1830 // The monitor we are exiting is not verifiably the one
1831 // on the top of our monitor stack. This causes a monitor
1832 // mismatch.
1833 _monitor_top = bad_monitors;
1834 _monitor_safe = false;
1835
1836 // We need to mark this basic block as changed so that
1837 // this monitorexit will be visited again. We need to
1838 // do this to ensure that we have accounted for the
1839 // possibility that this bytecode will throw an
1840 // exception.
1841 BasicBlock* bb = get_basic_block_containing(bci);
1842 guarantee(bb != NULL, "no basic block for bci");
1843 bb->set_changed(true);
1844 bb->_monitor_top = bad_monitors;
1845
1846 if (log_is_enabled(Info, monitormismatch)) {
1847 report_monitor_mismatch("improper monitor pair");
1848 }
1849 } else {
1850 // This code is a fix for the case where we have repeated
1851 // locking of the same object in straightline code. We clear
1852 // out the lock when it is popped from the monitor stack
1853 // and replace it with an unobtrusive reference value that can
1854 // be locked again.
1855 //
1856 // Note: when generateOopMap is fixed to properly handle repeated,
1857 // nested, redundant locks on the same object, then this
1858 // fix will need to be removed at that time.
1859 replace_all_CTS_matches(actual, CellTypeState::make_line_ref(bci));
1860 }
1861 }
1862
1863 void GenerateOopMap::do_return_monitor_check() {
1864 if (_monitor_top > 0) {
1865 // The monitor stack must be empty when we leave the method
1866 // for the monitors to be properly matched.
1867 _monitor_safe = false;
1868
1869 // Since there are no successors to the *return bytecode, it
1870 // isn't necessary to set _monitor_top to bad_monitors.
1871
1872 if (log_is_enabled(Info, monitormismatch)) {
1873 report_monitor_mismatch("non-empty monitor stack at return");
1874 }
1875 }
1876 }
1877
1878 void GenerateOopMap::do_jsr(int targ_bci) {
1879 push(CellTypeState::make_addr(targ_bci));
1880 }
1881
1882
1883
1884 void GenerateOopMap::do_ldc(int bci) {
1885 Bytecode_loadconstant ldc(methodHandle(Thread::current(), method()), bci);
1886 ConstantPool* cp = method()->constants();
1887 constantTag tag = cp->tag_at(ldc.pool_index()); // idx is index in resolved_references
1888 BasicType bt = ldc.result_type();
1889 #ifdef ASSERT
1890 BasicType tag_bt = (tag.is_dynamic_constant() || tag.is_dynamic_constant_in_error()) ? bt : tag.basic_type();
1891 assert(bt == tag_bt, "same result");
1892 #endif
1893 CellTypeState cts;
1894 if (is_reference_type(bt)) { // could be T_ARRAY with condy
1895 assert(!tag.is_string_index() && !tag.is_klass_index(), "Unexpected index tag");
1896 cts = CellTypeState::make_line_ref(bci);
1897 } else {
1898 cts = valCTS;
1899 }
1900 ppush1(cts);
1901 }
1902
1903 void GenerateOopMap::do_multianewarray(int dims, int bci) {
1904 assert(dims >= 1, "sanity check");
1905 for(int i = dims -1; i >=0; i--) {
1906 ppop1(valCTS);
1907 }
1908 ppush1(CellTypeState::make_line_ref(bci));
1909 }
1910
1911 void GenerateOopMap::do_astore(int idx) {
1912 CellTypeState r_or_p = pop();
1913 if (!r_or_p.is_address() && !r_or_p.is_reference()) {
1914 // We actually expected ref or pc, but we only report that we expected a ref. It does not
1915 // really matter (at least for now)
1916 verify_error("wrong type on stack (found: %c, expected: {pr})", r_or_p.to_char());
1917 return;
1918 }
1919 set_var(idx, r_or_p);
1920 }
1921
1922 // Copies bottom/zero terminated CTS string from "src" into "dst".
1923 // Does NOT terminate with a bottom. Returns the number of cells copied.
1924 int GenerateOopMap::copy_cts(CellTypeState *dst, CellTypeState *src) {
1925 int idx = 0;
1926 while (!src[idx].is_bottom()) {
1927 dst[idx] = src[idx];
1928 idx++;
1929 }
1930 return idx;
1931 }
1932
1933 void GenerateOopMap::do_field(int is_get, int is_static, int idx, int bci) {
1934 // Dig up signature for field in constant pool
1935 ConstantPool* cp = method()->constants();
1936 int nameAndTypeIdx = cp->name_and_type_ref_index_at(idx);
1937 int signatureIdx = cp->signature_ref_index_at(nameAndTypeIdx);
1938 Symbol* signature = cp->symbol_at(signatureIdx);
1939
1940 CellTypeState temp[4];
1941 CellTypeState *eff = signature_to_effect(signature, bci, temp);
1942
1943 CellTypeState in[4];
1944 CellTypeState *out;
1945 int i = 0;
1946
1947 if (is_get) {
1948 out = eff;
1949 } else {
1950 out = epsilonCTS;
1951 i = copy_cts(in, eff);
1952 }
1953 if (!is_static) {
1954 in[i++] = CellTypeState::ref;
1955 }
1956 in[i] = CellTypeState::bottom;
1957 assert(i<=3, "sanity check");
1958 pp(in, out);
1959 }
1960
1961 void GenerateOopMap::do_method(int is_static, int idx, int bci) {
1962 // Dig up signature for field in constant pool
1963 ConstantPool* cp = _method->constants();
1964 Symbol* signature = cp->signature_ref_at(idx);
1965
1966 // Parse method signature
1967 CellTypeState out[4];
1968 CellTypeState in[MAXARGSIZE+1]; // Includes result
1969 ComputeCallStack cse(signature);
1970
1971 // Compute return type
1972 int res_length= cse.compute_for_returntype(out);
1973
1974 // Temporary hack.
1975 if (out[0].equal(CellTypeState::ref) && out[1].equal(CellTypeState::bottom)) {
1976 out[0] = CellTypeState::make_line_ref(bci);
1977 }
1978
1979 assert(res_length<=4, "max value should be vv");
1980
1981 // Compute arguments
1982 int arg_length = cse.compute_for_parameters(is_static != 0, in);
1983 assert(arg_length<=MAXARGSIZE, "too many locals");
1984
1985 // Pop arguments
1986 for (int i = arg_length - 1; i >= 0; i--) ppop1(in[i]);// Do args in reverse order.
1987
1988 // Report results
1989 if (_report_result_for_send == true) {
1990 fill_stackmap_for_opcodes(_itr_send, vars(), stack(), _stack_top);
1991 _report_result_for_send = false;
1992 }
1993
1994 // Push return address
1995 ppush(out);
1996 }
1997
1998 void GenerateOopMap::do_withfield(int idx, int bci) {
1999 // Dig up signature for field in constant pool
2000 ConstantPool* cp = method()->constants();
2001 int nameAndTypeIdx = cp->name_and_type_ref_index_at(idx);
2002 int signatureIdx = cp->signature_ref_index_at(nameAndTypeIdx);
2003 Symbol* signature = cp->symbol_at(signatureIdx);
2004
2005 // Parse signature (especially simple for fields)
2006 assert(signature->utf8_length() > 0,
2007 "field signatures cannot have zero length");
2008 // The signature is UFT8 encoded, but the first char is always ASCII for signatures.
2009 CellTypeState temp[4];
2010 CellTypeState *eff = signature_to_effect(signature, bci, temp);
2011
2012 CellTypeState in[4];
2013 int i = copy_cts(in, eff);
2014 in[i++] = CellTypeState::ref;
2015 in[i] = CellTypeState::bottom;
2016 assert(i <= 3, "sanity check");
2017
2018 CellTypeState out[2];
2019 out[0] = CellTypeState::ref;
2020 out[1] = CellTypeState::bottom;
2021
2022 pp(in, out);
2023 }
2024
2025 // This is used to parse the signature for fields, since they are very simple...
2026 CellTypeState *GenerateOopMap::signature_to_effect(const Symbol* sig, int bci, CellTypeState *out) {
2027 // Object and array
2028 BasicType bt = Signature::basic_type(sig);
2029 if (is_reference_type(bt)) {
2030 out[0] = CellTypeState::make_line_ref(bci);
2031 out[1] = CellTypeState::bottom;
2032 return out;
2033 }
2034 if (is_double_word_type(bt)) return vvCTS; // Long and Double
2035 if (bt == T_VOID) return epsilonCTS; // Void
2036 return vCTS; // Otherwise
2037 }
2038
2039 uint64_t GenerateOopMap::_total_byte_count = 0;
2040 elapsedTimer GenerateOopMap::_total_oopmap_time;
2041
2042 // This function assumes "bcs" is at a "ret" instruction and that the vars
2043 // state is valid for that instruction. Furthermore, the ret instruction
2044 // must be the last instruction in "bb" (we store information about the
2045 // "ret" in "bb").
2046 void GenerateOopMap::ret_jump_targets_do(BytecodeStream *bcs, jmpFct_t jmpFct, int varNo, int *data) {
2047 CellTypeState ra = vars()[varNo];
2048 if (!ra.is_good_address()) {
2049 verify_error("ret returns from two jsr subroutines?");
2050 return;
2051 }
2052 int target = ra.get_info();
2053
2054 RetTableEntry* rtEnt = _rt.find_jsrs_for_target(target);
2055 int bci = bcs->bci();
2056 for (int i = 0; i < rtEnt->nof_jsrs(); i++) {
2057 int target_bci = rtEnt->jsrs(i);
2058 // Make sure a jrtRet does not set the changed bit for dead basicblock.
2059 BasicBlock* jsr_bb = get_basic_block_containing(target_bci - 1);
2060 debug_only(BasicBlock* target_bb = &jsr_bb[1];)
2061 assert(target_bb == get_basic_block_at(target_bci), "wrong calc. of successor basicblock");
2062 bool alive = jsr_bb->is_alive();
2063 if (TraceNewOopMapGeneration) {
2064 tty->print("pc = %d, ret -> %d alive: %s\n", bci, target_bci, alive ? "true" : "false");
2065 }
2066 if (alive) jmpFct(this, target_bci, data);
2067 }
2068 }
2069
2070 //
2071 // Debug method
2072 //
2073 char* GenerateOopMap::state_vec_to_string(CellTypeState* vec, int len) {
2074 #ifdef ASSERT
2075 int checklen = MAX3(_max_locals, _max_stack, _max_monitors) + 1;
2076 assert(len < checklen, "state_vec_buf overflow");
2077 #endif
2078 for (int i = 0; i < len; i++) _state_vec_buf[i] = vec[i].to_char();
2079 _state_vec_buf[len] = 0;
2080 return _state_vec_buf;
2081 }
2082
2083 void GenerateOopMap::print_time() {
2084 tty->print_cr ("Accumulated oopmap times:");
2085 tty->print_cr ("---------------------------");
2086 tty->print_cr (" Total : %3.3f sec.", GenerateOopMap::_total_oopmap_time.seconds());
2087 tty->print_cr (" (%3.0f bytecodes per sec) ",
2088 GenerateOopMap::_total_byte_count / GenerateOopMap::_total_oopmap_time.seconds());
2089 }
2090
2091 //
2092 // ============ Main Entry Point ===========
2093 //
2094 GenerateOopMap::GenerateOopMap(const methodHandle& method) {
2095 // We have to initialize all variables here, that can be queried directly
2096 _method = method;
2097 _max_locals=0;
2098 _init_vars = NULL;
2099
2100 #ifndef PRODUCT
2101 // If we are doing a detailed trace, include the regular trace information.
2102 if (TraceNewOopMapGenerationDetailed) {
2103 TraceNewOopMapGeneration = true;
2104 }
2105 #endif
2106 }
2107
2108 bool GenerateOopMap::compute_map(Thread* current) {
2109 #ifndef PRODUCT
2110 if (TimeOopMap2) {
2111 method()->print_short_name(tty);
2112 tty->print(" ");
2113 }
2114 if (TimeOopMap) {
2115 _total_byte_count += method()->code_size();
2116 }
2117 #endif
2118 TraceTime t_single("oopmap time", TimeOopMap2);
2119 TraceTime t_all(NULL, &_total_oopmap_time, TimeOopMap);
2120
2121 // Initialize values
2122 _got_error = false;
2123 _conflict = false;
2124 _max_locals = method()->max_locals();
2125 _max_stack = method()->max_stack();
2126 _has_exceptions = (method()->has_exception_handler());
2127 _nof_refval_conflicts = 0;
2128 _init_vars = new GrowableArray<intptr_t>(5); // There are seldom more than 5 init_vars
2129 _report_result = false;
2130 _report_result_for_send = false;
2131 _new_var_map = NULL;
2132 _ret_adr_tos = new GrowableArray<intptr_t>(5); // 5 seems like a good number;
2133 _did_rewriting = false;
2134 _did_relocation = false;
2135
2136 if (TraceNewOopMapGeneration) {
2137 tty->print("Method name: %s\n", method()->name()->as_C_string());
2138 if (Verbose) {
2139 _method->print_codes();
2140 tty->print_cr("Exception table:");
2141 ExceptionTable excps(method());
2142 for(int i = 0; i < excps.length(); i ++) {
2143 tty->print_cr("[%d - %d] -> %d",
2144 excps.start_pc(i), excps.end_pc(i), excps.handler_pc(i));
2145 }
2146 }
2147 }
2148
2149 // if no code - do nothing
2150 // compiler needs info
2151 if (method()->code_size() == 0 || _max_locals + method()->max_stack() == 0) {
2152 fill_stackmap_prolog(0);
2153 fill_stackmap_epilog();
2154 return true;
2155 }
2156 // Step 1: Compute all jump targets and their return value
2157 if (!_got_error)
2158 _rt.compute_ret_table(_method);
2159
2160 // Step 2: Find all basic blocks and count GC points
2161 if (!_got_error)
2162 mark_bbheaders_and_count_gc_points();
2163
2164 // Step 3: Calculate stack maps
2165 if (!_got_error)
2166 do_interpretation();
2167
2168 // Step 4:Return results
2169 if (!_got_error && report_results())
2170 report_result();
2171
2172 return !_got_error;
2173 }
2174
2175 // Error handling methods
2176 //
2177 // If we compute from a suitable JavaThread then we create an exception for the GenerateOopMap
2178 // calling code to retrieve (via exception()) and throw if desired (in most cases errors are ignored).
2179 // Otherwise it is considered a fatal error to hit malformed bytecode.
2180 void GenerateOopMap::error_work(const char *format, va_list ap) {
2181 _got_error = true;
2182 char msg_buffer[512];
2183 os::vsnprintf(msg_buffer, sizeof(msg_buffer), format, ap);
2184 // Append method name
2185 char msg_buffer2[512];
2186 os::snprintf(msg_buffer2, sizeof(msg_buffer2), "%s in method %s", msg_buffer, method()->name()->as_C_string());
2187 Thread* current = Thread::current();
2188 if (current->can_call_java()) {
2189 _exception = Exceptions::new_exception(JavaThread::cast(current),
2190 vmSymbols::java_lang_LinkageError(),
2191 msg_buffer2);
2192 } else {
2193 fatal("%s", msg_buffer2);
2194 }
2195 }
2196
2197 void GenerateOopMap::report_error(const char *format, ...) {
2198 va_list ap;
2199 va_start(ap, format);
2200 error_work(format, ap);
2201 }
2202
2203 void GenerateOopMap::verify_error(const char *format, ...) {
2204 // We do not distinguish between different types of errors for verification
2205 // errors. Let the verifier give a better message.
2206 report_error("Illegal class file encountered. Try running with -Xverify:all");
2207 }
2208
2209 //
2210 // Report result opcodes
2211 //
2212 void GenerateOopMap::report_result() {
2213
2214 if (TraceNewOopMapGeneration) tty->print_cr("Report result pass");
2215
2216 // We now want to report the result of the parse
2217 _report_result = true;
2218
2219 // Prolog code
2220 fill_stackmap_prolog(_gc_points);
2221
2222 // Mark everything changed, then do one interpretation pass.
2223 for (int i = 0; i<_bb_count; i++) {
2224 if (_basic_blocks[i].is_reachable()) {
2225 _basic_blocks[i].set_changed(true);
2226 interp_bb(&_basic_blocks[i]);
2227 }
2228 }
2229
2230 // Note: Since we are skipping dead-code when we are reporting results, then
2231 // the no. of encountered gc-points might be fewer than the previously number
2232 // we have counted. (dead-code is a pain - it should be removed before we get here)
2233 fill_stackmap_epilog();
2234
2235 // Report initvars
2236 fill_init_vars(_init_vars);
2237
2238 _report_result = false;
2239 }
2240
2241 void GenerateOopMap::result_for_basicblock(int bci) {
2242 if (TraceNewOopMapGeneration) tty->print_cr("Report result pass for basicblock");
2243
2244 // We now want to report the result of the parse
2245 _report_result = true;
2246
2247 // Find basicblock and report results
2248 BasicBlock* bb = get_basic_block_containing(bci);
2249 guarantee(bb != NULL, "no basic block for bci");
2250 assert(bb->is_reachable(), "getting result from unreachable basicblock");
2251 bb->set_changed(true);
2252 interp_bb(bb);
2253 }
2254
2255 //
2256 // Conflict handling code
2257 //
2258
2259 void GenerateOopMap::record_refval_conflict(int varNo) {
2260 assert(varNo>=0 && varNo< _max_locals, "index out of range");
2261
2262 if (TraceOopMapRewrites) {
2263 tty->print("### Conflict detected (local no: %d)\n", varNo);
2264 }
2265
2266 if (!_new_var_map) {
2267 _new_var_map = NEW_RESOURCE_ARRAY(int, _max_locals);
2268 for (int k = 0; k < _max_locals; k++) _new_var_map[k] = k;
2269 }
2270
2271 if ( _new_var_map[varNo] == varNo) {
2272 // Check if max. number of locals has been reached
2273 if (_max_locals + _nof_refval_conflicts >= MAX_LOCAL_VARS) {
2274 report_error("Rewriting exceeded local variable limit");
2275 return;
2276 }
2277 _new_var_map[varNo] = _max_locals + _nof_refval_conflicts;
2278 _nof_refval_conflicts++;
2279 }
2280 }
2281
2282 void GenerateOopMap::rewrite_refval_conflicts()
2283 {
2284 // We can get here two ways: Either a rewrite conflict was detected, or
2285 // an uninitialize reference was detected. In the second case, we do not
2286 // do any rewriting, we just want to recompute the reference set with the
2287 // new information
2288
2289 int nof_conflicts = 0; // Used for debugging only
2290
2291 if ( _nof_refval_conflicts == 0 )
2292 return;
2293
2294 // Check if rewrites are allowed in this parse.
2295 if (!allow_rewrites()) {
2296 fatal("Rewriting method not allowed at this stage");
2297 }
2298
2299
2300 // Tracing flag
2301 _did_rewriting = true;
2302
2303 if (TraceOopMapRewrites) {
2304 tty->print_cr("ref/value conflict for method %s - bytecodes are getting rewritten", method()->name()->as_C_string());
2305 method()->print();
2306 method()->print_codes();
2307 }
2308
2309 assert(_new_var_map!=NULL, "nothing to rewrite");
2310 assert(_conflict==true, "We should not be here");
2311
2312 compute_ret_adr_at_TOS();
2313 if (!_got_error) {
2314 for (int k = 0; k < _max_locals && !_got_error; k++) {
2315 if (_new_var_map[k] != k) {
2316 if (TraceOopMapRewrites) {
2317 tty->print_cr("Rewriting: %d -> %d", k, _new_var_map[k]);
2318 }
2319 rewrite_refval_conflict(k, _new_var_map[k]);
2320 if (_got_error) return;
2321 nof_conflicts++;
2322 }
2323 }
2324 }
2325
2326 assert(nof_conflicts == _nof_refval_conflicts, "sanity check");
2327
2328 // Adjust the number of locals
2329 method()->set_max_locals(_max_locals+_nof_refval_conflicts);
2330 _max_locals += _nof_refval_conflicts;
2331
2332 // That was that...
2333 _new_var_map = NULL;
2334 _nof_refval_conflicts = 0;
2335 }
2336
2337 void GenerateOopMap::rewrite_refval_conflict(int from, int to) {
2338 bool startOver;
2339 do {
2340 // Make sure that the BytecodeStream is constructed in the loop, since
2341 // during rewriting a new method is going to be used, and the next time
2342 // around we want to use that.
2343 BytecodeStream bcs(_method);
2344 startOver = false;
2345
2346 while( !startOver && !_got_error &&
2347 // test bcs in case method changed and it became invalid
2348 bcs.next() >=0) {
2349 startOver = rewrite_refval_conflict_inst(&bcs, from, to);
2350 }
2351 } while (startOver && !_got_error);
2352 }
2353
2354 /* If the current instruction is one that uses local variable "from"
2355 in a ref way, change it to use "to". There's a subtle reason why we
2356 renumber the ref uses and not the non-ref uses: non-ref uses may be
2357 2 slots wide (double, long) which would necessitate keeping track of
2358 whether we should add one or two variables to the method. If the change
2359 affected the width of some instruction, returns "TRUE"; otherwise, returns "FALSE".
2360 Another reason for moving ref's value is for solving (addr, ref) conflicts, which
2361 both uses aload/astore methods.
2362 */
2363 bool GenerateOopMap::rewrite_refval_conflict_inst(BytecodeStream *itr, int from, int to) {
2364 Bytecodes::Code bc = itr->code();
2365 int index;
2366 int bci = itr->bci();
2367
2368 if (is_aload(itr, &index) && index == from) {
2369 if (TraceOopMapRewrites) {
2370 tty->print_cr("Rewriting aload at bci: %d", bci);
2371 }
2372 return rewrite_load_or_store(itr, Bytecodes::_aload, Bytecodes::_aload_0, to);
2373 }
2374
2375 if (is_astore(itr, &index) && index == from) {
2376 if (!stack_top_holds_ret_addr(bci)) {
2377 if (TraceOopMapRewrites) {
2378 tty->print_cr("Rewriting astore at bci: %d", bci);
2379 }
2380 return rewrite_load_or_store(itr, Bytecodes::_astore, Bytecodes::_astore_0, to);
2381 } else {
2382 if (TraceOopMapRewrites) {
2383 tty->print_cr("Supress rewriting of astore at bci: %d", bci);
2384 }
2385 }
2386 }
2387
2388 return false;
2389 }
2390
2391 // The argument to this method is:
2392 // bc : Current bytecode
2393 // bcN : either _aload or _astore
2394 // bc0 : either _aload_0 or _astore_0
2395 bool GenerateOopMap::rewrite_load_or_store(BytecodeStream *bcs, Bytecodes::Code bcN, Bytecodes::Code bc0, unsigned int varNo) {
2396 assert(bcN == Bytecodes::_astore || bcN == Bytecodes::_aload, "wrong argument (bcN)");
2397 assert(bc0 == Bytecodes::_astore_0 || bc0 == Bytecodes::_aload_0, "wrong argument (bc0)");
2398 int ilen = Bytecodes::length_at(_method(), bcs->bcp());
2399 int newIlen;
2400
2401 if (ilen == 4) {
2402 // Original instruction was wide; keep it wide for simplicity
2403 newIlen = 4;
2404 } else if (varNo < 4)
2405 newIlen = 1;
2406 else if (varNo >= 256)
2407 newIlen = 4;
2408 else
2409 newIlen = 2;
2410
2411 // If we need to relocate in order to patch the byte, we
2412 // do the patching in a temp. buffer, that is passed to the reloc.
2413 // The patching of the bytecode stream is then done by the Relocator.
2414 // This is neccesary, since relocating the instruction at a certain bci, might
2415 // also relocate that instruction, e.g., if a _goto before it gets widen to a _goto_w.
2416 // Hence, we do not know which bci to patch after relocation.
2417
2418 assert(newIlen <= 4, "sanity check");
2419 u_char inst_buffer[4]; // Max. instruction size is 4.
2420 address bcp;
2421
2422 if (newIlen != ilen) {
2423 // Relocation needed do patching in temp. buffer
2424 bcp = (address)inst_buffer;
2425 } else {
2426 bcp = _method->bcp_from(bcs->bci());
2427 }
2428
2429 // Patch either directly in Method* or in temp. buffer
2430 if (newIlen == 1) {
2431 assert(varNo < 4, "varNo too large");
2432 *bcp = bc0 + varNo;
2433 } else if (newIlen == 2) {
2434 assert(varNo < 256, "2-byte index needed!");
2435 *(bcp + 0) = bcN;
2436 *(bcp + 1) = varNo;
2437 } else {
2438 assert(newIlen == 4, "Wrong instruction length");
2439 *(bcp + 0) = Bytecodes::_wide;
2440 *(bcp + 1) = bcN;
2441 Bytes::put_Java_u2(bcp+2, varNo);
2442 }
2443
2444 if (newIlen != ilen) {
2445 expand_current_instr(bcs->bci(), ilen, newIlen, inst_buffer);
2446 }
2447
2448
2449 return (newIlen != ilen);
2450 }
2451
2452 class RelocCallback : public RelocatorListener {
2453 private:
2454 GenerateOopMap* _gom;
2455 public:
2456 RelocCallback(GenerateOopMap* gom) { _gom = gom; };
2457
2458 // Callback method
2459 virtual void relocated(int bci, int delta, int new_code_length) {
2460 _gom->update_basic_blocks (bci, delta, new_code_length);
2461 _gom->update_ret_adr_at_TOS(bci, delta);
2462 _gom->_rt.update_ret_table (bci, delta);
2463 }
2464 };
2465
2466 // Returns true if expanding was succesful. Otherwise, reports an error and
2467 // returns false.
2468 void GenerateOopMap::expand_current_instr(int bci, int ilen, int newIlen, u_char inst_buffer[]) {
2469 JavaThread* THREAD = JavaThread::current(); // For exception macros.
2470 RelocCallback rcb(this);
2471 Relocator rc(_method, &rcb);
2472 methodHandle m= rc.insert_space_at(bci, newIlen, inst_buffer, THREAD);
2473 if (m.is_null() || HAS_PENDING_EXCEPTION) {
2474 report_error("could not rewrite method - exception occurred or bytecode buffer overflow");
2475 return;
2476 }
2477
2478 // Relocator returns a new method.
2479 _did_relocation = true;
2480 _method = m;
2481 }
2482
2483
2484 bool GenerateOopMap::is_astore(BytecodeStream *itr, int *index) {
2485 Bytecodes::Code bc = itr->code();
2486 switch(bc) {
2487 case Bytecodes::_astore_0:
2488 case Bytecodes::_astore_1:
2489 case Bytecodes::_astore_2:
2490 case Bytecodes::_astore_3:
2491 *index = bc - Bytecodes::_astore_0;
2492 return true;
2493 case Bytecodes::_astore:
2494 *index = itr->get_index();
2495 return true;
2496 default:
2497 return false;
2498 }
2499 }
2500
2501 bool GenerateOopMap::is_aload(BytecodeStream *itr, int *index) {
2502 Bytecodes::Code bc = itr->code();
2503 switch(bc) {
2504 case Bytecodes::_aload_0:
2505 case Bytecodes::_aload_1:
2506 case Bytecodes::_aload_2:
2507 case Bytecodes::_aload_3:
2508 *index = bc - Bytecodes::_aload_0;
2509 return true;
2510
2511 case Bytecodes::_aload:
2512 *index = itr->get_index();
2513 return true;
2514
2515 default:
2516 return false;
2517 }
2518 }
2519
2520
2521 // Return true iff the top of the operand stack holds a return address at
2522 // the current instruction
2523 bool GenerateOopMap::stack_top_holds_ret_addr(int bci) {
2524 for(int i = 0; i < _ret_adr_tos->length(); i++) {
2525 if (_ret_adr_tos->at(i) == bci)
2526 return true;
2527 }
2528
2529 return false;
2530 }
2531
2532 void GenerateOopMap::compute_ret_adr_at_TOS() {
2533 assert(_ret_adr_tos != NULL, "must be initialized");
2534 _ret_adr_tos->clear();
2535
2536 for (int i = 0; i < bb_count(); i++) {
2537 BasicBlock* bb = &_basic_blocks[i];
2538
2539 // Make sure to only check basicblocks that are reachable
2540 if (bb->is_reachable()) {
2541
2542 // For each Basic block we check all instructions
2543 BytecodeStream bcs(_method);
2544 bcs.set_interval(bb->_bci, next_bb_start_pc(bb));
2545
2546 restore_state(bb);
2547
2548 while (bcs.next()>=0 && !_got_error) {
2549 // TDT: should this be is_good_address() ?
2550 if (_stack_top > 0 && stack()[_stack_top-1].is_address()) {
2551 _ret_adr_tos->append(bcs.bci());
2552 if (TraceNewOopMapGeneration) {
2553 tty->print_cr("Ret_adr TOS at bci: %d", bcs.bci());
2554 }
2555 }
2556 interp1(&bcs);
2557 }
2558 }
2559 }
2560 }
2561
2562 void GenerateOopMap::update_ret_adr_at_TOS(int bci, int delta) {
2563 for(int i = 0; i < _ret_adr_tos->length(); i++) {
2564 int v = _ret_adr_tos->at(i);
2565 if (v > bci) _ret_adr_tos->at_put(i, v + delta);
2566 }
2567 }
2568
2569 // ===================================================================
2570
2571 #ifndef PRODUCT
2572 int ResolveOopMapConflicts::_nof_invocations = 0;
2573 int ResolveOopMapConflicts::_nof_rewrites = 0;
2574 int ResolveOopMapConflicts::_nof_relocations = 0;
2575 #endif
2576
2577 methodHandle ResolveOopMapConflicts::do_potential_rewrite(TRAPS) {
2578 if (!compute_map(THREAD)) {
2579 THROW_HANDLE_(exception(), methodHandle());
2580 }
2581
2582 #ifndef PRODUCT
2583 // Tracking and statistics
2584 if (PrintRewrites) {
2585 _nof_invocations++;
2586 if (did_rewriting()) {
2587 _nof_rewrites++;
2588 if (did_relocation()) _nof_relocations++;
2589 tty->print("Method was rewritten %s: ", (did_relocation()) ? "and relocated" : "");
2590 method()->print_value(); tty->cr();
2591 tty->print_cr("Cand.: %d rewrts: %d (%d%%) reloc.: %d (%d%%)",
2592 _nof_invocations,
2593 _nof_rewrites, (_nof_rewrites * 100) / _nof_invocations,
2594 _nof_relocations, (_nof_relocations * 100) / _nof_invocations);
2595 }
2596 }
2597 #endif
2598 return methodHandle(THREAD, method());
2599 }