1 #ifdef USE_PRAGMA_IDENT_SRC
2 #pragma ident "@(#)bcEscapeAnalyzer.cpp 1.7 07/05/17 15:49:50 JVM"
3 #endif
4 /*
5 * Copyright 2005-2006 Sun Microsystems, Inc. All Rights Reserved.
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
7 *
8 * This code is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 only, as
10 * published by the Free Software Foundation.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
24 * have any questions.
25 *
26 */
27
28
29 #include "incls/_precompiled.incl"
30 #include "incls/_bcEscapeAnalyzer.cpp.incl"
31
32
33 #ifndef PRODUCT
34 #define TRACE_BCEA(level, code) \
35 if (EstimateArgEscape && BCEATraceLevel >= level) { \
36 code; \
37 }
38 #else
39 #define TRACE_BCEA(level, code)
40 #endif
41
42 // Maintain a map of which aguments a local variable or
43 // stack slot may contain. In addition to tracking
44 // arguments, it tracks two special values, "allocated"
45 // which represents any object allocated in the current
46 // method, and "unknown" which is any other object.
47 // Up to 30 arguments are handled, with the last one
48 // representing summary information for any extra arguments
49 class BCEscapeAnalyzer::ArgumentMap {
50 uint _bits;
51 enum {MAXBIT = 29,
52 ALLOCATED = 1,
53 UNKNOWN = 2};
54
55 uint int_to_bit(uint e) const {
56 if (e > MAXBIT)
57 e = MAXBIT;
58 return (1 << (e + 2));
59 }
60
61 public:
62 ArgumentMap() { _bits = 0;}
63 void set_bits(uint bits) { _bits = bits;}
64 uint get_bits() const { return _bits;}
65 void clear() { _bits = 0;}
66 void set_all() { _bits = ~0u; }
67 bool is_empty() const { return _bits == 0; }
68 bool contains(uint var) const { return (_bits & int_to_bit(var)) != 0; }
69 bool is_singleton(uint var) const { return (_bits == int_to_bit(var)); }
70 bool contains_unknown() const { return (_bits & UNKNOWN) != 0; }
71 bool contains_allocated() const { return (_bits & ALLOCATED) != 0; }
72 bool contains_vars() const { return (_bits & (((1 << MAXBIT) -1) << 2)) != 0; }
73 void set(uint var) { _bits = int_to_bit(var); }
74 void add(uint var) { _bits |= int_to_bit(var); }
75 void add_unknown() { _bits = UNKNOWN; }
76 void add_allocated() { _bits = ALLOCATED; }
77 void set_union(const ArgumentMap &am) { _bits |= am._bits; }
78 void set_intersect(const ArgumentMap &am) { _bits |= am._bits; }
79 void set_difference(const ArgumentMap &am) { _bits &= ~am._bits; }
80 void operator=(const ArgumentMap &am) { _bits = am._bits; }
81 bool operator==(const ArgumentMap &am) { return _bits == am._bits; }
82 bool operator!=(const ArgumentMap &am) { return _bits != am._bits; }
83 };
84
85 class BCEscapeAnalyzer::StateInfo {
86 public:
87 ArgumentMap *_vars;
88 ArgumentMap *_stack;
89 short _stack_height;
90 short _max_stack;
91 bool _initialized;
92 ArgumentMap empty_map;
93
94 StateInfo() {
95 empty_map.clear();
96 }
97
98 ArgumentMap raw_pop() { assert(_stack_height > 0, "stack underflow"); return _stack[--_stack_height]; }
99 ArgumentMap apop() { return raw_pop(); }
100 void spop() { raw_pop(); }
101 void lpop() { spop(); spop(); }
102 void raw_push(ArgumentMap i) { assert(_stack_height < _max_stack, "stack overflow"); _stack[_stack_height++] = i; }
103 void apush(ArgumentMap i) { raw_push(i); }
104 void spush() { raw_push(empty_map); }
105 void lpush() { spush(); spush(); }
106
107 };
108
109 void BCEscapeAnalyzer::set_returned(ArgumentMap vars) {
110 for (int i = 0; i <= _arg_size; i++) {
111 if (vars.contains(i))
112 _arg_returned.set_bit(i);
113 }
114 _return_local = _return_local && !(vars.contains_unknown() || vars.contains_allocated());
115 _return_allocated = _return_allocated && vars.contains_allocated() && !(vars.contains_unknown() || vars.contains_vars());
116 }
117
118
119 // return true if any element of vars is an argument
120 bool BCEscapeAnalyzer::is_argument(ArgumentMap vars) {
121 for (int i = 0; i <= _arg_size; i++) {
122 if (vars.contains(i))
123 return true;
124 }
125 return false;
126 }
127
128 // return true if any element of vars is an arg_stack argument
129 bool BCEscapeAnalyzer::is_arg_stack(ArgumentMap vars){
130 if (_conservative)
131 return true;
132 for (int i = 0; i <= _arg_size; i++) {
133 if (vars.contains(i) && _arg_stack.at(i))
134 return true;
135 }
136 return false;
137 }
138
139 void BCEscapeAnalyzer::clear_bits(ArgumentMap vars, BitMap &bm) {
140 for (int i = 0; i <= _arg_size; i++) {
141 if (vars.contains(i)) {
142 bm.clear_bit(i);
143 }
144 }
145 }
146 void BCEscapeAnalyzer::set_method_escape(ArgumentMap vars) {
147 clear_bits(vars, _arg_local);
148 }
149
150 void BCEscapeAnalyzer::set_global_escape(ArgumentMap vars) {
151 clear_bits(vars, _arg_local);
152 clear_bits(vars, _arg_stack);
153 if (vars.contains_allocated())
154 _allocated_escapes = true;
155 }
156
157 void BCEscapeAnalyzer::set_dirty(ArgumentMap vars) {
158 clear_bits(vars, _dirty);
159 }
160
161 bool BCEscapeAnalyzer::is_recursive_call(ciMethod* callee) {
162 for (BCEscapeAnalyzer* scope = this; scope != NULL; scope = scope->_parent) {
163 if (scope->method() == callee) {
164 return true;
165 }
166 }
167 return false;
168 }
169
170 void BCEscapeAnalyzer::invoke(StateInfo &state, Bytecodes::Code code, ciMethod* target, ciKlass* holder) {
171 int i;
172
173 // retrieve information about the callee
174 ciInstanceKlass* klass = target->holder();
175 ciInstanceKlass* calling_klass = method()->holder();
176 ciInstanceKlass* callee_holder = ciEnv::get_instance_klass_for_declared_method_holder(holder);
177 ciInstanceKlass* actual_recv = callee_holder;
178
179 // compute size of arguments
180 int arg_size = target->arg_size();
181 if (!target->is_loaded() && code == Bytecodes::_invokestatic) {
182 arg_size--;
183 }
184 int arg_base = MAX2(state._stack_height - arg_size, 0);
185
186 // direct recursive calls are skipped if they can be bound statically without introducing
187 // dependencies and if parameters are passed at the same position as in the current method
188 // other calls are skipped if there are no unescaped arguments passed to them
189 bool directly_recursive = (method() == target) &&
190 (code != Bytecodes::_invokevirtual || target->is_final_method() || state._stack[arg_base] .is_empty());
191
192 // check if analysis of callee can safely be skipped
193 bool skip_callee = true;
194 for (i = state._stack_height - 1; i >= arg_base && skip_callee; i--) {
195 ArgumentMap arg = state._stack[i];
196 skip_callee = !is_argument(arg) || !is_arg_stack(arg) || (directly_recursive && arg.is_singleton(i - arg_base));
197 }
198 if (skip_callee) {
199 TRACE_BCEA(3, tty->print_cr("[EA] skipping method %s::%s", holder->name()->as_utf8(), target->name()->as_utf8()));
200 for (i = 0; i < arg_size; i++) {
201 set_method_escape(state.raw_pop());
202 }
203 return;
204 }
205
206 // determine actual method (use CHA if necessary)
207 ciMethod* inline_target = NULL;
208 if (target->is_loaded() && klass->is_loaded()
209 && (klass->is_initialized() || klass->is_interface() && target->holder()->is_initialized())
210 && target->will_link(klass, callee_holder, code)) {
211 if (code == Bytecodes::_invokestatic
212 || code == Bytecodes::_invokespecial
213 || code == Bytecodes::_invokevirtual && target->is_final_method()) {
214 inline_target = target;
215 } else {
216 inline_target = target->find_monomorphic_target(calling_klass, callee_holder, actual_recv);
217 }
218 }
219
220 if (inline_target != NULL && !is_recursive_call(inline_target)) {
221 // analyze callee
222 BCEscapeAnalyzer analyzer(inline_target, this);
223
224 // adjust escape state of actual parameters
225 bool must_record_dependencies = false;
226 for (i = arg_size - 1; i >= 0; i--) {
227 ArgumentMap arg = state.raw_pop();
228 if (!is_argument(arg))
229 continue;
230 if (!is_arg_stack(arg)) {
231 // arguments have already been recognized as escaping
232 } else if (analyzer.is_arg_stack(i) && !analyzer.is_arg_returned(i)) {
233 set_method_escape(arg);
234 must_record_dependencies = true;
235 } else {
236 set_global_escape(arg);
237 }
238 }
239
240 // record dependencies if at least one parameter retained stack-allocatable
241 if (must_record_dependencies) {
242 if (code == Bytecodes::_invokeinterface || code == Bytecodes::_invokevirtual && !target->is_final_method()) {
243 _dependencies.append(actual_recv);
244 _dependencies.append(inline_target);
245 }
246 _dependencies.appendAll(analyzer.dependencies());
247 }
248 } else {
249 TRACE_BCEA(1, tty->print_cr("[EA] virtual method %s is not monomorphic.",
250 target->name()->as_utf8()));
251 // conservatively mark all actual parameters as escaping globally
252 for (i = 0; i < arg_size; i++) {
253 ArgumentMap arg = state.raw_pop();
254 if (!is_argument(arg))
255 continue;
256 set_global_escape(arg);
257 }
258 }
259 }
260
261 bool BCEscapeAnalyzer::contains(uint arg_set1, uint arg_set2) {
262 return ((~arg_set1) | arg_set2) == 0;
263 }
264
265
266 void BCEscapeAnalyzer::iterate_one_block(ciBlock *blk, StateInfo &state, GrowableArray<ciBlock *> &successors) {
267
268 blk->set_processed();
269 ciBytecodeStream s(method());
270 int limit_bci = blk->limit_bci();
271 bool fall_through = false;
272 ArgumentMap allocated_obj;
273 allocated_obj.add_allocated();
274 ArgumentMap unknown_obj;
275 unknown_obj.add_unknown();
276 ArgumentMap empty_map;
277
278 s.reset_to_bci(blk->start_bci());
279 while (s.next() != ciBytecodeStream::EOBC() && s.cur_bci() < limit_bci) {
280 fall_through = true;
281 switch (s.cur_bc()) {
282 case Bytecodes::_nop:
283 break;
284 case Bytecodes::_aconst_null:
285 state.apush(empty_map);
286 break;
287 case Bytecodes::_iconst_m1:
288 case Bytecodes::_iconst_0:
289 case Bytecodes::_iconst_1:
290 case Bytecodes::_iconst_2:
291 case Bytecodes::_iconst_3:
292 case Bytecodes::_iconst_4:
293 case Bytecodes::_iconst_5:
294 case Bytecodes::_fconst_0:
295 case Bytecodes::_fconst_1:
296 case Bytecodes::_fconst_2:
297 case Bytecodes::_bipush:
298 case Bytecodes::_sipush:
299 state.spush();
300 break;
301 case Bytecodes::_lconst_0:
302 case Bytecodes::_lconst_1:
303 case Bytecodes::_dconst_0:
304 case Bytecodes::_dconst_1:
305 state.lpush();
306 break;
307 case Bytecodes::_ldc:
308 case Bytecodes::_ldc_w:
309 case Bytecodes::_ldc2_w:
310 if (type2size[s.get_constant().basic_type()] == 1) {
311 state.spush();
312 } else {
313 state.lpush();
314 }
315 break;
316 case Bytecodes::_aload:
317 state.apush(state._vars[s.get_index()]);
318 break;
319 case Bytecodes::_iload:
320 case Bytecodes::_fload:
321 case Bytecodes::_iload_0:
322 case Bytecodes::_iload_1:
323 case Bytecodes::_iload_2:
324 case Bytecodes::_iload_3:
325 case Bytecodes::_fload_0:
326 case Bytecodes::_fload_1:
327 case Bytecodes::_fload_2:
328 case Bytecodes::_fload_3:
329 state.spush();
330 break;
331 case Bytecodes::_lload:
332 case Bytecodes::_dload:
333 case Bytecodes::_lload_0:
334 case Bytecodes::_lload_1:
335 case Bytecodes::_lload_2:
336 case Bytecodes::_lload_3:
337 case Bytecodes::_dload_0:
338 case Bytecodes::_dload_1:
339 case Bytecodes::_dload_2:
340 case Bytecodes::_dload_3:
341 state.lpush();
342 break;
343 case Bytecodes::_aload_0:
344 state.apush(state._vars[0]);
345 break;
346 case Bytecodes::_aload_1:
347 state.apush(state._vars[1]);
348 break;
349 case Bytecodes::_aload_2:
350 state.apush(state._vars[2]);
351 break;
352 case Bytecodes::_aload_3:
353 state.apush(state._vars[3]);
354 break;
355 case Bytecodes::_iaload:
356 case Bytecodes::_faload:
357 case Bytecodes::_baload:
358 case Bytecodes::_caload:
359 case Bytecodes::_saload:
360 state.spop();
361 set_method_escape(state.apop());
362 state.spush();
363 break;
364 case Bytecodes::_laload:
365 case Bytecodes::_daload:
366 state.spop();
367 set_method_escape(state.apop());
368 state.lpush();
369 break;
370 case Bytecodes::_aaload:
371 { state.spop();
372 ArgumentMap array = state.apop();
373 set_method_escape(array);
374 state.apush(unknown_obj);
375 set_dirty(array);
376 }
377 break;
378 case Bytecodes::_istore:
379 case Bytecodes::_fstore:
380 case Bytecodes::_istore_0:
381 case Bytecodes::_istore_1:
382 case Bytecodes::_istore_2:
383 case Bytecodes::_istore_3:
384 case Bytecodes::_fstore_0:
385 case Bytecodes::_fstore_1:
386 case Bytecodes::_fstore_2:
387 case Bytecodes::_fstore_3:
388 state.spop();
389 break;
390 case Bytecodes::_lstore:
391 case Bytecodes::_dstore:
392 case Bytecodes::_lstore_0:
393 case Bytecodes::_lstore_1:
394 case Bytecodes::_lstore_2:
395 case Bytecodes::_lstore_3:
396 case Bytecodes::_dstore_0:
397 case Bytecodes::_dstore_1:
398 case Bytecodes::_dstore_2:
399 case Bytecodes::_dstore_3:
400 state.lpop();
401 break;
402 case Bytecodes::_astore:
403 state._vars[s.get_index()] = state.apop();
404 break;
405 case Bytecodes::_astore_0:
406 state._vars[0] = state.apop();
407 break;
408 case Bytecodes::_astore_1:
409 state._vars[1] = state.apop();
410 break;
411 case Bytecodes::_astore_2:
412 state._vars[2] = state.apop();
413 break;
414 case Bytecodes::_astore_3:
415 state._vars[3] = state.apop();
416 break;
417 case Bytecodes::_iastore:
418 case Bytecodes::_fastore:
419 case Bytecodes::_bastore:
420 case Bytecodes::_castore:
421 case Bytecodes::_sastore:
422 {
423 state.spop();
424 state.spop();
425 ArgumentMap arr = state.apop();
426 set_method_escape(arr);
427 break;
428 }
429 case Bytecodes::_lastore:
430 case Bytecodes::_dastore:
431 {
432 state.lpop();
433 state.spop();
434 ArgumentMap arr = state.apop();
435 set_method_escape(arr);
436 break;
437 }
438 case Bytecodes::_aastore:
439 {
440 set_global_escape(state.apop());
441 state.spop();
442 ArgumentMap arr = state.apop();
443 break;
444 }
445 case Bytecodes::_pop:
446 state.raw_pop();
447 break;
448 case Bytecodes::_pop2:
449 state.raw_pop();
450 state.raw_pop();
451 break;
452 case Bytecodes::_dup:
453 { ArgumentMap w1 = state.raw_pop();
454 state.raw_push(w1);
455 state.raw_push(w1);
456 }
457 break;
458 case Bytecodes::_dup_x1:
459 { ArgumentMap w1 = state.raw_pop();
460 ArgumentMap w2 = state.raw_pop();
461 state.raw_push(w1);
462 state.raw_push(w2);
463 state.raw_push(w1);
464 }
465 break;
466 case Bytecodes::_dup_x2:
467 { ArgumentMap w1 = state.raw_pop();
468 ArgumentMap w2 = state.raw_pop();
469 ArgumentMap w3 = state.raw_pop();
470 state.raw_push(w1);
471 state.raw_push(w3);
472 state.raw_push(w2);
473 state.raw_push(w1);
474 }
475 break;
476 case Bytecodes::_dup2:
477 { ArgumentMap w1 = state.raw_pop();
478 ArgumentMap w2 = state.raw_pop();
479 state.raw_push(w2);
480 state.raw_push(w1);
481 state.raw_push(w2);
482 state.raw_push(w1);
483 }
484 break;
485 case Bytecodes::_dup2_x1:
486 { ArgumentMap w1 = state.raw_pop();
487 ArgumentMap w2 = state.raw_pop();
488 ArgumentMap w3 = state.raw_pop();
489 state.raw_push(w2);
490 state.raw_push(w1);
491 state.raw_push(w3);
492 state.raw_push(w2);
493 state.raw_push(w1);
494 }
495 break;
496 case Bytecodes::_dup2_x2:
497 { ArgumentMap w1 = state.raw_pop();
498 ArgumentMap w2 = state.raw_pop();
499 ArgumentMap w3 = state.raw_pop();
500 ArgumentMap w4 = state.raw_pop();
501 state.raw_push(w2);
502 state.raw_push(w1);
503 state.raw_push(w4);
504 state.raw_push(w3);
505 state.raw_push(w2);
506 state.raw_push(w1);
507 }
508 break;
509 case Bytecodes::_swap:
510 { ArgumentMap w1 = state.raw_pop();
511 ArgumentMap w2 = state.raw_pop();
512 state.raw_push(w1);
513 state.raw_push(w2);
514 }
515 break;
516 case Bytecodes::_iadd:
517 case Bytecodes::_fadd:
518 case Bytecodes::_isub:
519 case Bytecodes::_fsub:
520 case Bytecodes::_imul:
521 case Bytecodes::_fmul:
522 case Bytecodes::_idiv:
523 case Bytecodes::_fdiv:
524 case Bytecodes::_irem:
525 case Bytecodes::_frem:
526 case Bytecodes::_iand:
527 case Bytecodes::_ior:
528 case Bytecodes::_ixor:
529 state.spop();
530 state.spop();
531 state.spush();
532 break;
533 case Bytecodes::_ladd:
534 case Bytecodes::_dadd:
535 case Bytecodes::_lsub:
536 case Bytecodes::_dsub:
537 case Bytecodes::_lmul:
538 case Bytecodes::_dmul:
539 case Bytecodes::_ldiv:
540 case Bytecodes::_ddiv:
541 case Bytecodes::_lrem:
542 case Bytecodes::_drem:
543 case Bytecodes::_land:
544 case Bytecodes::_lor:
545 case Bytecodes::_lxor:
546 state.lpop();
547 state.lpop();
548 state.lpush();
549 break;
550 case Bytecodes::_ishl:
551 case Bytecodes::_ishr:
552 case Bytecodes::_iushr:
553 state.spop();
554 state.spop();
555 state.spush();
556 break;
557 case Bytecodes::_lshl:
558 case Bytecodes::_lshr:
559 case Bytecodes::_lushr:
560 state.spop();
561 state.lpop();
562 state.lpush();
563 break;
564 case Bytecodes::_ineg:
565 case Bytecodes::_fneg:
566 state.spop();
567 state.spush();
568 break;
569 case Bytecodes::_lneg:
570 case Bytecodes::_dneg:
571 state.lpop();
572 state.lpush();
573 break;
574 case Bytecodes::_iinc:
575 break;
576 case Bytecodes::_i2l:
577 case Bytecodes::_i2d:
578 case Bytecodes::_f2l:
579 case Bytecodes::_f2d:
580 state.spop();
581 state.lpush();
582 break;
583 case Bytecodes::_i2f:
584 case Bytecodes::_f2i:
585 state.spop();
586 state.spush();
587 break;
588 case Bytecodes::_l2i:
589 case Bytecodes::_l2f:
590 case Bytecodes::_d2i:
591 case Bytecodes::_d2f:
592 state.lpop();
593 state.spush();
594 break;
595 case Bytecodes::_l2d:
596 case Bytecodes::_d2l:
597 state.lpop();
598 state.lpush();
599 break;
600 case Bytecodes::_i2b:
601 case Bytecodes::_i2c:
602 case Bytecodes::_i2s:
603 state.spop();
604 state.spush();
605 break;
606 case Bytecodes::_lcmp:
607 case Bytecodes::_dcmpl:
608 case Bytecodes::_dcmpg:
609 state.lpop();
610 state.lpop();
611 state.spush();
612 break;
613 case Bytecodes::_fcmpl:
614 case Bytecodes::_fcmpg:
615 state.spop();
616 state.spop();
617 state.spush();
618 break;
619 case Bytecodes::_ifeq:
620 case Bytecodes::_ifne:
621 case Bytecodes::_iflt:
622 case Bytecodes::_ifge:
623 case Bytecodes::_ifgt:
624 case Bytecodes::_ifle:
625 {
626 state.spop();
627 int dest_bci = s.get_dest();
628 assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
629 assert(s.next_bci() == limit_bci, "branch must end block");
630 successors.push(_methodBlocks->block_containing(dest_bci));
631 break;
632 }
633 case Bytecodes::_if_icmpeq:
634 case Bytecodes::_if_icmpne:
635 case Bytecodes::_if_icmplt:
636 case Bytecodes::_if_icmpge:
637 case Bytecodes::_if_icmpgt:
638 case Bytecodes::_if_icmple:
639 {
640 state.spop();
641 state.spop();
642 int dest_bci = s.get_dest();
643 assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
644 assert(s.next_bci() == limit_bci, "branch must end block");
645 successors.push(_methodBlocks->block_containing(dest_bci));
646 break;
647 }
648 case Bytecodes::_if_acmpeq:
649 case Bytecodes::_if_acmpne:
650 {
651 set_method_escape(state.apop());
652 set_method_escape(state.apop());
653 int dest_bci = s.get_dest();
654 assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
655 assert(s.next_bci() == limit_bci, "branch must end block");
656 successors.push(_methodBlocks->block_containing(dest_bci));
657 break;
658 }
659 case Bytecodes::_goto:
660 {
661 int dest_bci = s.get_dest();
662 assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
663 assert(s.next_bci() == limit_bci, "branch must end block");
664 successors.push(_methodBlocks->block_containing(dest_bci));
665 fall_through = false;
666 break;
667 }
668 case Bytecodes::_jsr:
669 {
670 int dest_bci = s.get_dest();
671 assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
672 assert(s.next_bci() == limit_bci, "branch must end block");
673 state.apush(empty_map);
674 successors.push(_methodBlocks->block_containing(dest_bci));
675 fall_through = false;
676 break;
677 }
678 case Bytecodes::_ret:
679 // we don't track the destination of a "ret" instruction
680 assert(s.next_bci() == limit_bci, "branch must end block");
681 fall_through = false;
682 break;
683 case Bytecodes::_return:
684 assert(s.next_bci() == limit_bci, "return must end block");
685 fall_through = false;
686 break;
687 case Bytecodes::_tableswitch:
688 {
689 state.spop();
690 Bytecode_tableswitch* switch_ = Bytecode_tableswitch_at(s.cur_bcp());
691 int len = switch_->length();
692 int dest_bci;
693 for (int i = 0; i < len; i++) {
694 dest_bci = s.cur_bci() + switch_->dest_offset_at(i);
695 assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
696 successors.push(_methodBlocks->block_containing(dest_bci));
697 }
698 dest_bci = s.cur_bci() + switch_->default_offset();
699 assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
700 successors.push(_methodBlocks->block_containing(dest_bci));
701 assert(s.next_bci() == limit_bci, "branch must end block");
702 fall_through = false;
703 break;
704 }
705 case Bytecodes::_lookupswitch:
706 {
707 state.spop();
708 Bytecode_lookupswitch* switch_ = Bytecode_lookupswitch_at(s.cur_bcp());
709 int len = switch_->number_of_pairs();
710 int dest_bci;
711 for (int i = 0; i < len; i++) {
712 dest_bci = s.cur_bci() + switch_->pair_at(i)->offset();
713 assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
714 successors.push(_methodBlocks->block_containing(dest_bci));
715 }
716 dest_bci = s.cur_bci() + switch_->default_offset();
717 assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
718 successors.push(_methodBlocks->block_containing(dest_bci));
719 fall_through = false;
720 break;
721 }
722 case Bytecodes::_ireturn:
723 case Bytecodes::_freturn:
724 state.spop();
725 fall_through = false;
726 break;
727 case Bytecodes::_lreturn:
728 case Bytecodes::_dreturn:
729 state.lpop();
730 fall_through = false;
731 break;
732 case Bytecodes::_areturn:
733 set_returned(state.apop());
734 fall_through = false;
735 break;
736 case Bytecodes::_getstatic:
737 case Bytecodes::_getfield:
738 { bool will_link;
739 ciField* field = s.get_field(will_link);
740 BasicType field_type = field->type()->basic_type();
741 if (s.cur_bc() != Bytecodes::_getstatic) {
742 set_method_escape(state.apop());
743 }
744 if (field_type == T_OBJECT || field_type == T_ARRAY) {
745 state.apush(unknown_obj);
746 } else if (type2size[field_type] == 1) {
747 state.spush();
748 } else {
749 state.lpush();
750 }
751 }
752 break;
753 case Bytecodes::_putstatic:
754 case Bytecodes::_putfield:
755 { bool will_link;
756 ciField* field = s.get_field(will_link);
757 BasicType field_type = field->type()->basic_type();
758 if (field_type == T_OBJECT || field_type == T_ARRAY) {
759 set_global_escape(state.apop());
760 } else if (type2size[field_type] == 1) {
761 state.spop();
762 } else {
763 state.lpop();
764 }
765 if (s.cur_bc() != Bytecodes::_putstatic) {
766 ArgumentMap p = state.apop();
767 set_method_escape(p);
768 }
769 }
770 break;
771 case Bytecodes::_invokevirtual:
772 case Bytecodes::_invokespecial:
773 case Bytecodes::_invokestatic:
774 case Bytecodes::_invokeinterface:
775 { bool will_link;
776 ciMethod* target = s.get_method(will_link);
777 ciKlass* holder = s.get_declared_method_holder();
778 invoke(state, s.cur_bc(), target, holder);
779 ciType* return_type = target->return_type();
780 if (!return_type->is_primitive_type()) {
781 state.apush(unknown_obj);
782 } else if (return_type->is_one_word()) {
783 state.spush();
784 } else if (return_type->is_two_word()) {
785 state.lpush();
786 }
787 }
788 break;
789 case Bytecodes::_xxxunusedxxx:
790 ShouldNotReachHere();
791 break;
792 case Bytecodes::_new:
793 state.apush(allocated_obj);
794 break;
795 case Bytecodes::_newarray:
796 case Bytecodes::_anewarray:
797 state.spop();
798 state.apush(allocated_obj);
799 break;
800 case Bytecodes::_multianewarray:
801 { int i = s.cur_bcp()[3];
802 while (i-- > 0) state.spop();
803 state.apush(allocated_obj);
804 }
805 break;
806 case Bytecodes::_arraylength:
807 set_method_escape(state.apop());
808 state.spush();
809 break;
810 case Bytecodes::_athrow:
811 set_global_escape(state.apop());
812 fall_through = false;
813 break;
814 case Bytecodes::_checkcast:
815 { ArgumentMap obj = state.apop();
816 set_method_escape(obj);
817 state.apush(obj);
818 }
819 break;
820 case Bytecodes::_instanceof:
821 set_method_escape(state.apop());
822 state.spush();
823 break;
824 case Bytecodes::_monitorenter:
825 case Bytecodes::_monitorexit:
826 state.apop();
827 break;
828 case Bytecodes::_wide:
829 ShouldNotReachHere();
830 break;
831 case Bytecodes::_ifnull:
832 case Bytecodes::_ifnonnull:
833 {
834 set_method_escape(state.apop());
835 int dest_bci = s.get_dest();
836 assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
837 assert(s.next_bci() == limit_bci, "branch must end block");
838 successors.push(_methodBlocks->block_containing(dest_bci));
839 break;
840 }
841 case Bytecodes::_goto_w:
842 {
843 int dest_bci = s.get_far_dest();
844 assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
845 assert(s.next_bci() == limit_bci, "branch must end block");
846 successors.push(_methodBlocks->block_containing(dest_bci));
847 fall_through = false;
848 break;
849 }
850 case Bytecodes::_jsr_w:
851 {
852 int dest_bci = s.get_far_dest();
853 assert(_methodBlocks->is_block_start(dest_bci), "branch destination must start a block");
854 assert(s.next_bci() == limit_bci, "branch must end block");
855 state.apush(empty_map);
856 successors.push(_methodBlocks->block_containing(dest_bci));
857 fall_through = false;
858 break;
859 }
860 case Bytecodes::_breakpoint:
861 break;
862 default:
863 ShouldNotReachHere();
864 break;
865 }
866
867 }
868 if (fall_through) {
869 int fall_through_bci = s.cur_bci();
870 if (fall_through_bci < _method->code_size()) {
871 assert(_methodBlocks->is_block_start(fall_through_bci), "must fall through to block start.");
872 successors.push(_methodBlocks->block_containing(fall_through_bci));
873 }
874 }
875 }
876
877 void BCEscapeAnalyzer::merge_block_states(StateInfo *blockstates, ciBlock *dest, StateInfo *s_state) {
878 StateInfo *d_state = blockstates+dest->index();
879 int nlocals = _method->max_locals();
880
881 // exceptions may cause transfer of control to handlers in the middle of a
882 // block, so we don't merge the incoming state of exception handlers
883 if (dest->is_handler())
884 return;
885 if (!d_state->_initialized ) {
886 // destination not initialized, just copy
887 for (int i = 0; i < nlocals; i++) {
888 d_state->_vars[i] = s_state->_vars[i];
889 }
890 for (int i = 0; i < s_state->_stack_height; i++) {
891 d_state->_stack[i] = s_state->_stack[i];
892 }
893 d_state->_stack_height = s_state->_stack_height;
894 d_state->_max_stack = s_state->_max_stack;
895 d_state->_initialized = true;
896 } else if (!dest->processed()) {
897 // we have not yet walked the bytecodes of dest, we can merge
898 // the states
899 assert(d_state->_stack_height == s_state->_stack_height, "computed stack heights must match");
900 for (int i = 0; i < nlocals; i++) {
901 d_state->_vars[i].set_union(s_state->_vars[i]);
902 }
903 for (int i = 0; i < s_state->_stack_height; i++) {
904 d_state->_stack[i].set_union(s_state->_stack[i]);
905 }
906 } else {
907 // the bytecodes of dest have already been processed, mark any
908 // arguments in the source state which are not in the dest state
909 // as global escape.
910 // Future refinement: we only need to mark these variable to the
911 // maximum escape of any variables in dest state
912 assert(d_state->_stack_height == s_state->_stack_height, "computed stack heights must match");
913 ArgumentMap extra_vars;
914 for (int i = 0; i < nlocals; i++) {
915 ArgumentMap t;
916 t = s_state->_vars[i];
917 t.set_difference(d_state->_vars[i]);
918 extra_vars.set_union(t);
919 }
920 for (int i = 0; i < s_state->_stack_height; i++) {
921 ArgumentMap t;
922 t.clear();
923 t = s_state->_stack[i];
924 t.set_difference(d_state->_stack[i]);
925 extra_vars.set_union(t);
926 }
927 set_global_escape(extra_vars);
928 }
929 }
930
931 void BCEscapeAnalyzer::iterate_blocks(Arena *arena) {
932 int numblocks = _methodBlocks->num_blocks();
933 int stkSize = _method->max_stack();
934 int numLocals = _method->max_locals();
935 StateInfo state;
936
937 int datacount = (numblocks + 1) * (stkSize + numLocals);
938 int datasize = datacount * sizeof(ArgumentMap);
939 StateInfo *blockstates = (StateInfo *) arena->Amalloc(_methodBlocks->num_blocks() * sizeof(StateInfo));
940 ArgumentMap *statedata = (ArgumentMap *) arena->Amalloc(datasize);
941 for (int i = 0; i < datacount; i++) ::new ((void*)&statedata[i]) ArgumentMap();
942 ArgumentMap *dp = statedata;
943 state._vars = dp;
944 dp += numLocals;
945 state._stack = dp;
946 dp += stkSize;
947 state._initialized = false;
948 state._max_stack = stkSize;
949 for (int i = 0; i < numblocks; i++) {
950 blockstates[i]._vars = dp;
951 dp += numLocals;
952 blockstates[i]._stack = dp;
953 dp += stkSize;
954 blockstates[i]._initialized = false;
955 blockstates[i]._stack_height = 0;
956 blockstates[i]._max_stack = stkSize;
957 }
958 GrowableArray<ciBlock *> worklist(arena, numblocks / 4, 0, NULL);
959 GrowableArray<ciBlock *> successors(arena, 4, 0, NULL);
960
961 _methodBlocks->clear_processed();
962
963 // initialize block 0 state from method signature
964 ArgumentMap allVars; // all oop arguments to method
965 ciSignature* sig = method()->signature();
966 int j = 0;
967 if (!method()->is_static()) {
968 // record information for "this"
969 blockstates[0]._vars[j].set(j);
970 allVars.add(j);
971 j++;
972 }
973 for (int i = 0; i < sig->count(); i++) {
974 ciType* t = sig->type_at(i);
975 if (!t->is_primitive_type()) {
976 blockstates[0]._vars[j].set(j);
977 allVars.add(j);
978 }
979 j += t->size();
980 }
981 blockstates[0]._initialized = true;
982 assert(j == _arg_size, "just checking");
983
984 ArgumentMap unknown_map;
985 unknown_map.add_unknown();
986
987 worklist.push(_methodBlocks->block_containing(0));
988 while(worklist.length() > 0) {
989 ciBlock *blk = worklist.pop();
990 StateInfo *blkState = blockstates+blk->index();
991 if (blk->is_handler() || blk->is_ret_target()) {
992 // for an exception handler or a target of a ret instruction, we assume the worst case,
993 // that any variable or stack slot could contain any argument
994 for (int i = 0; i < numLocals; i++) {
995 state._vars[i] = allVars;
996 }
997 if (blk->is_handler()) {
998 state._stack_height = 1;
999 } else {
1000 state._stack_height = blkState->_stack_height;
1001 }
1002 for (int i = 0; i < state._stack_height; i++) {
1003 state._stack[i] = allVars;
1004 }
1005 } else {
1006 for (int i = 0; i < numLocals; i++) {
1007 state._vars[i] = blkState->_vars[i];
1008 }
1009 for (int i = 0; i < blkState->_stack_height; i++) {
1010 state._stack[i] = blkState->_stack[i];
1011 }
1012 state._stack_height = blkState->_stack_height;
1013 }
1014 iterate_one_block(blk, state, successors);
1015 // if this block has any exception handlers, push them
1016 // onto successor list
1017 if (blk->has_handler()) {
1018 DEBUG_ONLY(int handler_count = 0;)
1019 int blk_start = blk->start_bci();
1020 int blk_end = blk->limit_bci();
1021 for (int i = 0; i < numblocks; i++) {
1022 ciBlock *b = _methodBlocks->block(i);
1023 if (b->is_handler()) {
1024 int ex_start = b->ex_start_bci();
1025 int ex_end = b->ex_limit_bci();
1026 if ((ex_start >= blk_start && ex_start < blk_end) ||
1027 (ex_end > blk_start && ex_end <= blk_end)) {
1028 successors.push(b);
1029 }
1030 DEBUG_ONLY(handler_count++;)
1031 }
1032 }
1033 assert(handler_count > 0, "must find at least one handler");
1034 }
1035 // merge computed variable state with successors
1036 while(successors.length() > 0) {
1037 ciBlock *succ = successors.pop();
1038 merge_block_states(blockstates, succ, &state);
1039 if (!succ->processed())
1040 worklist.push(succ);
1041 }
1042 }
1043 }
1044
1045 bool BCEscapeAnalyzer::do_analysis() {
1046 Arena* arena = CURRENT_ENV->arena();
1047 // identify basic blocks
1048 _methodBlocks = _method->get_method_blocks();
1049
1050 iterate_blocks(arena);
1051 // TEMPORARY
1052 return true;
1053 }
1054
1055 vmIntrinsics::ID BCEscapeAnalyzer::known_intrinsic() {
1056 vmIntrinsics::ID iid = method()->intrinsic_id();
1057
1058 if (iid == vmIntrinsics::_getClass ||
1059 iid == vmIntrinsics::_hashCode)
1060 return iid;
1061 else
1062 return vmIntrinsics::_none;
1063 }
1064
1065 bool BCEscapeAnalyzer::compute_escape_for_intrinsic(vmIntrinsics::ID iid) {
1066 ArgumentMap empty;
1067 empty.clear();
1068 switch (iid) {
1069 case vmIntrinsics::_getClass:
1070 _return_local = false;
1071 break;
1072 case vmIntrinsics::_hashCode:
1073 // initialized state is correct
1074 break;
1075 default:
1076 assert(false, "unexpected intrinsic");
1077 }
1078 return true;
1079 }
1080
1081 void BCEscapeAnalyzer::initialize() {
1082 int i;
1083
1084 // clear escape information (method may have been deoptimized)
1085 methodData()->clear_escape_info();
1086
1087 // initialize escape state of object parameters
1088 ciSignature* sig = method()->signature();
1089 int j = 0;
1090 if (!method()->is_static()) {
1091 _arg_local.set_bit(0);
1092 _arg_stack.set_bit(0);
1093 j++;
1094 }
1095 for (i = 0; i < sig->count(); i++) {
1096 ciType* t = sig->type_at(i);
1097 if (!t->is_primitive_type()) {
1098 _arg_local.set_bit(j);
1099 _arg_stack.set_bit(j);
1100 }
1101 j += t->size();
1102 }
1103 assert(j == _arg_size, "just checking");
1104
1105 // start with optimistic assumption
1106 ciType *rt = _method->return_type();
1107 if (rt->is_primitive_type()) {
1108 _return_local = false;
1109 _return_allocated = false;
1110 } else {
1111 _return_local = true;
1112 _return_allocated = true;
1113 }
1114 _allocated_escapes = false;
1115 }
1116
1117 void BCEscapeAnalyzer::clear_escape_info() {
1118 ciSignature* sig = method()->signature();
1119 int arg_count = sig->count();
1120 ArgumentMap var;
1121 for (int i = 0; i < arg_count; i++) {
1122 var.clear();
1123 var.set(i);
1124 set_global_escape(var);
1125 }
1126 _arg_local.clear();
1127 _arg_stack.clear();
1128 _arg_returned.clear();
1129 _return_local = false;
1130 _return_allocated = false;
1131 _allocated_escapes = true;
1132 }
1133
1134
1135 void BCEscapeAnalyzer::compute_escape_info() {
1136 int i;
1137 assert(!methodData()->has_escape_info(), "do not overwrite escape info");
1138
1139 vmIntrinsics::ID iid = known_intrinsic();
1140
1141 // check if method can be analyzed
1142 if (iid == vmIntrinsics::_none && (method()->is_abstract() || method()->is_native() || !method()->holder()->is_initialized()
1143 || _level > MaxBCEAEstimateLevel
1144 || method()->code_size() > MaxBCEAEstimateSize)) {
1145 if (BCEATraceLevel >= 1) {
1146 tty->print("Skipping method because: ");
1147 if (method()->is_abstract())
1148 tty->print_cr("method is abstract.");
1149 else if (method()->is_native())
1150 tty->print_cr("method is native.");
1151 else if (!method()->holder()->is_initialized())
1152 tty->print_cr("class of method is not initialized.");
1153 else if (_level > MaxBCEAEstimateLevel)
1154 tty->print_cr("level (%d) exceeds MaxBCEAEstimateLevel (%d).",
1155 _level, MaxBCEAEstimateLevel);
1156 else if (method()->code_size() > MaxBCEAEstimateSize)
1157 tty->print_cr("code size (%d) exceeds MaxBCEAEstimateSize.",
1158 method()->code_size(), MaxBCEAEstimateSize);
1159 else
1160 ShouldNotReachHere();
1161 }
1162 clear_escape_info();
1163
1164 return;
1165 }
1166
1167 if (BCEATraceLevel >= 1) {
1168 tty->print("[EA] estimating escape information for");
1169 if (iid != vmIntrinsics::_none)
1170 tty->print(" intrinsic");
1171 method()->print_short_name();
1172 tty->print_cr(" (%d bytes)", method()->code_size());
1173 }
1174
1175 bool success;
1176
1177 initialize();
1178
1179 // do not scan method if it has no object parameters
1180 if (_arg_local.is_empty()) {
1181 methodData()->set_eflag(methodDataOopDesc::estimated);
1182 return;
1183 }
1184
1185 if (iid != vmIntrinsics::_none)
1186 success = compute_escape_for_intrinsic(iid);
1187 else {
1188 success = do_analysis();
1189 }
1190
1191 // dump result of bytecode analysis
1192 #ifndef PRODUCT
1193 if (BCEATraceLevel >= 3) {
1194 tty->print("[EA] estimated escape information for");
1195 if (iid != vmIntrinsics::_none)
1196 tty->print(" intrinsic");
1197 method()->print_short_name();
1198 tty->print_cr(has_dependencies() ? " (not stored)" : "");
1199 tty->print(" non-escaping args: ");
1200 _arg_local.print_on(tty);
1201 tty->print(" stack-allocatable args: ");
1202 _arg_stack.print_on(tty);
1203 if (_return_local) {
1204 tty->print(" returned args: ");
1205 _arg_returned.print_on(tty);
1206 } else if (is_return_allocated()) {
1207 tty->print_cr(" allocated return values");
1208 } else {
1209 tty->print_cr(" non-local return values");
1210 }
1211 tty->cr();
1212 tty->print(" flags: ");
1213 if (_return_allocated)
1214 tty->print(" return_allocated");
1215 tty->cr();
1216 }
1217
1218 #endif
1219 // don't store interprocedural escape information if it introduces dependencies
1220 // or if method data is empty
1221 //
1222 if (!has_dependencies() && !methodData()->is_empty()) {
1223 for (i = 0; i < _arg_size; i++) {
1224 if (_arg_local.at(i)) {
1225 assert(_arg_stack.at(i), "inconsistent escape info");
1226 methodData()->set_arg_local(i);
1227 methodData()->set_arg_stack(i);
1228 } else if (_arg_stack.at(i)) {
1229 methodData()->set_arg_stack(i);
1230 }
1231 if (_arg_returned.at(i)) {
1232 methodData()->set_arg_returned(i);
1233 }
1234 }
1235 if (_return_local) {
1236 methodData()->set_eflag(methodDataOopDesc::return_local);
1237 }
1238 methodData()->set_eflag(methodDataOopDesc::estimated);
1239 }
1240 }
1241
1242 void BCEscapeAnalyzer::read_escape_info() {
1243 assert(methodData()->has_escape_info(), "no escape info available");
1244
1245 // read escape information from method descriptor
1246 for (int i = 0; i < _arg_size; i++) {
1247 _arg_local.at_put(i, methodData()->is_arg_local(i));
1248 _arg_stack.at_put(i, methodData()->is_arg_stack(i));
1249 _arg_returned.at_put(i, methodData()->is_arg_returned(i));
1250 }
1251 _return_local = methodData()->eflag_set(methodDataOopDesc::return_local);
1252
1253 // dump result of loaded escape information
1254 #ifndef PRODUCT
1255 if (BCEATraceLevel >= 4) {
1256 tty->print(" non-escaping args: ");
1257 _arg_local.print_on(tty);
1258 tty->print(" stack-allocatable args: ");
1259 _arg_stack.print_on(tty);
1260 if (_return_local) {
1261 tty->print(" returned args: ");
1262 _arg_returned.print_on(tty);
1263 } else {
1264 tty->print_cr(" non-local return values");
1265 }
1266 tty->print(" modified args: ");
1267 tty->cr();
1268 }
1269 #endif
1270
1271 }
1272
1273
1274 BCEscapeAnalyzer::BCEscapeAnalyzer(ciMethod* method, BCEscapeAnalyzer* parent)
1275 : _conservative(method == NULL || !EstimateArgEscape)
1276 , _method(method)
1277 , _methodData(method ? method->method_data() : NULL)
1278 , _arg_size(method ? method->arg_size() : 0)
1279 , _stack()
1280 , _arg_local(_arg_size)
1281 , _arg_stack(_arg_size)
1282 , _arg_returned(_arg_size)
1283 , _dirty(_arg_size)
1284 , _return_local(false)
1285 , _return_allocated(false)
1286 , _allocated_escapes(false)
1287 , _dependencies()
1288 , _parent(parent)
1289 , _level(parent == NULL ? 0 : parent->level() + 1) {
1290 if (!_conservative) {
1291 _arg_local.clear();
1292 _arg_stack.clear();
1293 _arg_returned.clear();
1294 _dirty.clear();
1295 Arena* arena = CURRENT_ENV->arena();
1296
1297 if (methodData() == NULL)
1298 return;
1299 bool printit = _method->should_print_assembly();
1300 if (methodData()->has_escape_info()) {
1301 TRACE_BCEA(2, tty->print_cr("[EA] Reading previous results for %s.%s",
1302 method->holder()->name()->as_utf8(),
1303 method->name()->as_utf8()));
1304 read_escape_info();
1305 } else {
1306 TRACE_BCEA(2, tty->print_cr("[EA] computing results for %s.%s",
1307 method->holder()->name()->as_utf8(),
1308 method->name()->as_utf8()));
1309
1310 compute_escape_info();
1311 methodData()->update_escape_info();
1312 }
1313 }
1314 }
1315
1316 void BCEscapeAnalyzer::copy_dependencies(Dependencies *deps) {
1317 if(!has_dependencies())
1318 return;
1319 for (int i = 0; i < _dependencies.length(); i+=2) {
1320 ciKlass *k = _dependencies[i]->as_klass();
1321 ciMethod *m = _dependencies[i+1]->as_method();
1322 deps->assert_unique_concrete_method(k, m);
1323 }
1324 }
1325