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