1 /*
2 * Copyright (c) 1999, 2012, 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 "c1/c1_Canonicalizer.hpp"
27 #include "c1/c1_Optimizer.hpp"
28 #include "c1/c1_ValueMap.hpp"
29 #include "c1/c1_ValueSet.hpp"
30 #include "c1/c1_ValueStack.hpp"
31 #include "utilities/bitMap.inline.hpp"
32 #include "compiler/compileLog.hpp"
33
34 define_array(ValueSetArray, ValueSet*);
35 define_stack(ValueSetList, ValueSetArray);
36
37
38 Optimizer::Optimizer(IR* ir) {
39 assert(ir->is_valid(), "IR must be valid");
40 _ir = ir;
41 }
42
43 class CE_Eliminator: public BlockClosure {
44 private:
45 IR* _hir;
46 int _cee_count; // the number of CEs successfully eliminated
47 int _ifop_count; // the number of IfOps successfully simplified
48 int _has_substitution;
49
50 public:
51 CE_Eliminator(IR* hir) : _cee_count(0), _ifop_count(0), _hir(hir) {
52 _has_substitution = false;
53 _hir->iterate_preorder(this);
54 if (_has_substitution) {
55 // substituted some ifops/phis, so resolve the substitution
56 SubstitutionResolver sr(_hir);
57 }
58
59 CompileLog* log = _hir->compilation()->log();
60 if (log != NULL)
61 log->set_context("optimize name='cee'");
62 }
63
64 ~CE_Eliminator() {
65 CompileLog* log = _hir->compilation()->log();
66 if (log != NULL)
67 log->clear_context(); // skip marker if nothing was printed
68 }
69
70 int cee_count() const { return _cee_count; }
71 int ifop_count() const { return _ifop_count; }
72
73 void adjust_exception_edges(BlockBegin* block, BlockBegin* sux) {
74 int e = sux->number_of_exception_handlers();
75 for (int i = 0; i < e; i++) {
76 BlockBegin* xhandler = sux->exception_handler_at(i);
77 block->add_exception_handler(xhandler);
78
79 assert(xhandler->is_predecessor(sux), "missing predecessor");
80 if (sux->number_of_preds() == 0) {
81 // sux is disconnected from graph so disconnect from exception handlers
82 xhandler->remove_predecessor(sux);
83 }
84 if (!xhandler->is_predecessor(block)) {
85 xhandler->add_predecessor(block);
86 }
87 }
88 }
89
90 virtual void block_do(BlockBegin* block);
91
92 private:
93 Value make_ifop(Value x, Instruction::Condition cond, Value y, Value tval, Value fval);
94 };
95
96 void CE_Eliminator::block_do(BlockBegin* block) {
97 // 1) find conditional expression
98 // check if block ends with an If
99 If* if_ = block->end()->as_If();
100 if (if_ == NULL) return;
101
102 // check if If works on int or object types
103 // (we cannot handle If's working on long, float or doubles yet,
104 // since IfOp doesn't support them - these If's show up if cmp
105 // operations followed by If's are eliminated)
106 ValueType* if_type = if_->x()->type();
107 if (!if_type->is_int() && !if_type->is_object()) return;
108
109 BlockBegin* t_block = if_->tsux();
110 BlockBegin* f_block = if_->fsux();
111 Instruction* t_cur = t_block->next();
112 Instruction* f_cur = f_block->next();
113
114 // one Constant may be present between BlockBegin and BlockEnd
115 Value t_const = NULL;
116 Value f_const = NULL;
117 if (t_cur->as_Constant() != NULL && !t_cur->can_trap()) {
118 t_const = t_cur;
119 t_cur = t_cur->next();
120 }
121 if (f_cur->as_Constant() != NULL && !f_cur->can_trap()) {
122 f_const = f_cur;
123 f_cur = f_cur->next();
124 }
125
126 // check if both branches end with a goto
127 Goto* t_goto = t_cur->as_Goto();
128 if (t_goto == NULL) return;
129 Goto* f_goto = f_cur->as_Goto();
130 if (f_goto == NULL) return;
131
132 // check if both gotos merge into the same block
133 BlockBegin* sux = t_goto->default_sux();
134 if (sux != f_goto->default_sux()) return;
135
136 // check if at least one word was pushed on sux_state
137 // inlining depths must match
138 ValueStack* if_state = if_->state();
139 ValueStack* sux_state = sux->state();
140 if (if_state->scope()->level() > sux_state->scope()->level()) {
141 while (sux_state->scope() != if_state->scope()) {
142 if_state = if_state->caller_state();
143 assert(if_state != NULL, "states do not match up");
144 }
145 } else if (if_state->scope()->level() < sux_state->scope()->level()) {
146 while (sux_state->scope() != if_state->scope()) {
147 sux_state = sux_state->caller_state();
148 assert(sux_state != NULL, "states do not match up");
149 }
150 }
151
152 if (sux_state->stack_size() <= if_state->stack_size()) return;
153
154 // check if phi function is present at end of successor stack and that
155 // only this phi was pushed on the stack
156 Value sux_phi = sux_state->stack_at(if_state->stack_size());
157 if (sux_phi == NULL || sux_phi->as_Phi() == NULL || sux_phi->as_Phi()->block() != sux) return;
158 if (sux_phi->type()->size() != sux_state->stack_size() - if_state->stack_size()) return;
159
160 // get the values that were pushed in the true- and false-branch
161 Value t_value = t_goto->state()->stack_at(if_state->stack_size());
162 Value f_value = f_goto->state()->stack_at(if_state->stack_size());
163
164 // backend does not support floats
165 assert(t_value->type()->base() == f_value->type()->base(), "incompatible types");
166 if (t_value->type()->is_float_kind()) return;
167
168 // check that successor has no other phi functions but sux_phi
169 // this can happen when t_block or f_block contained additonal stores to local variables
170 // that are no longer represented by explicit instructions
171 for_each_phi_fun(sux, phi,
172 if (phi != sux_phi) return;
173 );
174 // true and false blocks can't have phis
175 for_each_phi_fun(t_block, phi, return; );
176 for_each_phi_fun(f_block, phi, return; );
177
178 // 2) substitute conditional expression
179 // with an IfOp followed by a Goto
180 // cut if_ away and get node before
181 Instruction* cur_end = if_->prev();
182
183 // append constants of true- and false-block if necessary
184 // clone constants because original block must not be destroyed
185 assert((t_value != f_const && f_value != t_const) || t_const == f_const, "mismatch");
186 if (t_value == t_const) {
187 t_value = new Constant(t_const->type());
188 NOT_PRODUCT(t_value->set_printable_bci(if_->printable_bci()));
189 cur_end = cur_end->set_next(t_value);
190 }
191 if (f_value == f_const) {
192 f_value = new Constant(f_const->type());
193 NOT_PRODUCT(f_value->set_printable_bci(if_->printable_bci()));
194 cur_end = cur_end->set_next(f_value);
195 }
196
197 Value result = make_ifop(if_->x(), if_->cond(), if_->y(), t_value, f_value);
198 assert(result != NULL, "make_ifop must return a non-null instruction");
199 if (!result->is_linked() && result->can_be_linked()) {
200 NOT_PRODUCT(result->set_printable_bci(if_->printable_bci()));
201 cur_end = cur_end->set_next(result);
202 }
203
204 // append Goto to successor
205 ValueStack* state_before = if_->state_before();
206 Goto* goto_ = new Goto(sux, state_before, if_->is_safepoint() || t_goto->is_safepoint() || f_goto->is_safepoint());
207
208 // prepare state for Goto
209 ValueStack* goto_state = if_state;
210 goto_state = goto_state->copy(ValueStack::StateAfter, goto_state->bci());
211 goto_state->push(result->type(), result);
212 assert(goto_state->is_same(sux_state), "states must match now");
213 goto_->set_state(goto_state);
214
215 cur_end = cur_end->set_next(goto_, goto_state->bci());
216
217 // Adjust control flow graph
218 BlockBegin::disconnect_edge(block, t_block);
219 BlockBegin::disconnect_edge(block, f_block);
220 if (t_block->number_of_preds() == 0) {
221 BlockBegin::disconnect_edge(t_block, sux);
222 }
223 adjust_exception_edges(block, t_block);
224 if (f_block->number_of_preds() == 0) {
225 BlockBegin::disconnect_edge(f_block, sux);
226 }
227 adjust_exception_edges(block, f_block);
228
229 // update block end
230 block->set_end(goto_);
231
232 // substitute the phi if possible
233 if (sux_phi->as_Phi()->operand_count() == 1) {
234 assert(sux_phi->as_Phi()->operand_at(0) == result, "screwed up phi");
235 sux_phi->set_subst(result);
236 _has_substitution = true;
237 }
238
239 // 3) successfully eliminated a conditional expression
240 _cee_count++;
241 if (PrintCEE) {
242 tty->print_cr("%d. CEE in B%d (B%d B%d)", cee_count(), block->block_id(), t_block->block_id(), f_block->block_id());
243 tty->print_cr("%d. IfOp in B%d", ifop_count(), block->block_id());
244 }
245
246 _hir->verify();
247 }
248
249 Value CE_Eliminator::make_ifop(Value x, Instruction::Condition cond, Value y, Value tval, Value fval) {
250 if (!OptimizeIfOps) {
251 return new IfOp(x, cond, y, tval, fval);
252 }
253
254 tval = tval->subst();
255 fval = fval->subst();
256 if (tval == fval) {
257 _ifop_count++;
258 return tval;
259 }
260
261 x = x->subst();
262 y = y->subst();
263
264 Constant* y_const = y->as_Constant();
265 if (y_const != NULL) {
266 IfOp* x_ifop = x->as_IfOp();
267 if (x_ifop != NULL) { // x is an ifop, y is a constant
268 Constant* x_tval_const = x_ifop->tval()->subst()->as_Constant();
269 Constant* x_fval_const = x_ifop->fval()->subst()->as_Constant();
270
271 if (x_tval_const != NULL && x_fval_const != NULL) {
272 Instruction::Condition x_ifop_cond = x_ifop->cond();
273
274 Constant::CompareResult t_compare_res = x_tval_const->compare(cond, y_const);
275 Constant::CompareResult f_compare_res = x_fval_const->compare(cond, y_const);
276
277 // not_comparable here is a valid return in case we're comparing unloaded oop constants
278 if (t_compare_res != Constant::not_comparable && f_compare_res != Constant::not_comparable) {
279 Value new_tval = t_compare_res == Constant::cond_true ? tval : fval;
280 Value new_fval = f_compare_res == Constant::cond_true ? tval : fval;
281
282 _ifop_count++;
283 if (new_tval == new_fval) {
284 return new_tval;
285 } else {
286 return new IfOp(x_ifop->x(), x_ifop_cond, x_ifop->y(), new_tval, new_fval);
287 }
288 }
289 }
290 } else {
291 Constant* x_const = x->as_Constant();
292 if (x_const != NULL) { // x and y are constants
293 Constant::CompareResult x_compare_res = x_const->compare(cond, y_const);
294 // not_comparable here is a valid return in case we're comparing unloaded oop constants
295 if (x_compare_res != Constant::not_comparable) {
296 _ifop_count++;
297 return x_compare_res == Constant::cond_true ? tval : fval;
298 }
299 }
300 }
301 }
302 return new IfOp(x, cond, y, tval, fval);
303 }
304
305 void Optimizer::eliminate_conditional_expressions() {
306 // find conditional expressions & replace them with IfOps
307 CE_Eliminator ce(ir());
308 }
309
310 class BlockMerger: public BlockClosure {
311 private:
312 IR* _hir;
313 int _merge_count; // the number of block pairs successfully merged
314
315 public:
316 BlockMerger(IR* hir)
317 : _hir(hir)
318 , _merge_count(0)
319 {
320 _hir->iterate_preorder(this);
321 CompileLog* log = _hir->compilation()->log();
322 if (log != NULL)
323 log->set_context("optimize name='eliminate_blocks'");
324 }
325
326 ~BlockMerger() {
327 CompileLog* log = _hir->compilation()->log();
328 if (log != NULL)
329 log->clear_context(); // skip marker if nothing was printed
330 }
331
332 bool try_merge(BlockBegin* block) {
333 BlockEnd* end = block->end();
334 if (end->as_Goto() != NULL) {
335 assert(end->number_of_sux() == 1, "end must have exactly one successor");
336 // Note: It would be sufficient to check for the number of successors (= 1)
337 // in order to decide if this block can be merged potentially. That
338 // would then also include switch statements w/ only a default case.
339 // However, in that case we would need to make sure the switch tag
340 // expression is executed if it can produce observable side effects.
341 // We should probably have the canonicalizer simplifying such switch
342 // statements and then we are sure we don't miss these merge opportunities
343 // here (was bug - gri 7/7/99).
344 BlockBegin* sux = end->default_sux();
345 if (sux->number_of_preds() == 1 && !sux->is_entry_block() && !end->is_safepoint()) {
346 // merge the two blocks
347
348 #ifdef ASSERT
349 // verify that state at the end of block and at the beginning of sux are equal
350 // no phi functions must be present at beginning of sux
351 ValueStack* sux_state = sux->state();
352 ValueStack* end_state = end->state();
353
354 assert(end_state->scope() == sux_state->scope(), "scopes must match");
355 assert(end_state->stack_size() == sux_state->stack_size(), "stack not equal");
356 assert(end_state->locals_size() == sux_state->locals_size(), "locals not equal");
357
358 int index;
359 Value sux_value;
360 for_each_stack_value(sux_state, index, sux_value) {
361 assert(sux_value == end_state->stack_at(index), "stack not equal");
362 }
363 for_each_local_value(sux_state, index, sux_value) {
364 assert(sux_value == end_state->local_at(index), "locals not equal");
365 }
366 assert(sux_state->caller_state() == end_state->caller_state(), "caller not equal");
367 #endif
368
369 // find instruction before end & append first instruction of sux block
370 Instruction* prev = end->prev();
371 Instruction* next = sux->next();
372 assert(prev->as_BlockEnd() == NULL, "must not be a BlockEnd");
373 prev->set_next(next);
374 prev->fixup_block_pointers();
375 sux->disconnect_from_graph();
376 block->set_end(sux->end());
377 // add exception handlers of deleted block, if any
378 for (int k = 0; k < sux->number_of_exception_handlers(); k++) {
379 BlockBegin* xhandler = sux->exception_handler_at(k);
380 block->add_exception_handler(xhandler);
381
382 // also substitute predecessor of exception handler
383 assert(xhandler->is_predecessor(sux), "missing predecessor");
384 xhandler->remove_predecessor(sux);
385 if (!xhandler->is_predecessor(block)) {
386 xhandler->add_predecessor(block);
387 }
388 }
389
390 // debugging output
391 _merge_count++;
392 if (PrintBlockElimination) {
393 tty->print_cr("%d. merged B%d & B%d (stack size = %d)",
394 _merge_count, block->block_id(), sux->block_id(), sux->state()->stack_size());
395 }
396
397 _hir->verify();
398
399 If* if_ = block->end()->as_If();
400 if (if_) {
401 IfOp* ifop = if_->x()->as_IfOp();
402 Constant* con = if_->y()->as_Constant();
403 bool swapped = false;
404 if (!con || !ifop) {
405 ifop = if_->y()->as_IfOp();
406 con = if_->x()->as_Constant();
407 swapped = true;
408 }
409 if (con && ifop) {
410 Constant* tval = ifop->tval()->as_Constant();
411 Constant* fval = ifop->fval()->as_Constant();
412 if (tval && fval) {
413 // Find the instruction before if_, starting with ifop.
414 // When if_ and ifop are not in the same block, prev
415 // becomes NULL In such (rare) cases it is not
416 // profitable to perform the optimization.
417 Value prev = ifop;
418 while (prev != NULL && prev->next() != if_) {
419 prev = prev->next();
420 }
421
422 if (prev != NULL) {
423 Instruction::Condition cond = if_->cond();
424 BlockBegin* tsux = if_->tsux();
425 BlockBegin* fsux = if_->fsux();
426 if (swapped) {
427 cond = Instruction::mirror(cond);
428 }
429
430 BlockBegin* tblock = tval->compare(cond, con, tsux, fsux);
431 BlockBegin* fblock = fval->compare(cond, con, tsux, fsux);
432 if (tblock != fblock && !if_->is_safepoint()) {
433 If* newif = new If(ifop->x(), ifop->cond(), false, ifop->y(),
434 tblock, fblock, if_->state_before(), if_->is_safepoint());
435 newif->set_state(if_->state()->copy());
436
437 assert(prev->next() == if_, "must be guaranteed by above search");
438 NOT_PRODUCT(newif->set_printable_bci(if_->printable_bci()));
439 prev->set_next(newif);
440 block->set_end(newif);
441
442 _merge_count++;
443 if (PrintBlockElimination) {
444 tty->print_cr("%d. replaced If and IfOp at end of B%d with single If", _merge_count, block->block_id());
445 }
446
447 _hir->verify();
448 }
449 }
450 }
451 }
452 }
453
454 return true;
455 }
456 }
457 return false;
458 }
459
460 virtual void block_do(BlockBegin* block) {
461 _hir->verify();
462 // repeat since the same block may merge again
463 while (try_merge(block)) {
464 _hir->verify();
465 }
466 }
467 };
468
469
470 void Optimizer::eliminate_blocks() {
471 // merge blocks if possible
472 BlockMerger bm(ir());
473 }
474
475
476 class NullCheckEliminator;
477 class NullCheckVisitor: public InstructionVisitor {
478 private:
479 NullCheckEliminator* _nce;
480 NullCheckEliminator* nce() { return _nce; }
481
482 public:
483 NullCheckVisitor() {}
484
485 void set_eliminator(NullCheckEliminator* nce) { _nce = nce; }
486
487 void do_Phi (Phi* x);
488 void do_Local (Local* x);
489 void do_Constant (Constant* x);
490 void do_LoadField (LoadField* x);
491 void do_StoreField (StoreField* x);
492 void do_ArrayLength (ArrayLength* x);
493 void do_LoadIndexed (LoadIndexed* x);
494 void do_StoreIndexed (StoreIndexed* x);
495 void do_NegateOp (NegateOp* x);
496 void do_ArithmeticOp (ArithmeticOp* x);
497 void do_ShiftOp (ShiftOp* x);
498 void do_LogicOp (LogicOp* x);
499 void do_CompareOp (CompareOp* x);
500 void do_IfOp (IfOp* x);
501 void do_Convert (Convert* x);
502 void do_NullCheck (NullCheck* x);
503 void do_TypeCast (TypeCast* x);
504 void do_Invoke (Invoke* x);
505 void do_NewInstance (NewInstance* x);
506 void do_NewTypeArray (NewTypeArray* x);
507 void do_NewObjectArray (NewObjectArray* x);
508 void do_NewMultiArray (NewMultiArray* x);
509 void do_CheckCast (CheckCast* x);
510 void do_InstanceOf (InstanceOf* x);
511 void do_MonitorEnter (MonitorEnter* x);
512 void do_MonitorExit (MonitorExit* x);
513 void do_Intrinsic (Intrinsic* x);
514 void do_BlockBegin (BlockBegin* x);
515 void do_Goto (Goto* x);
516 void do_If (If* x);
517 void do_IfInstanceOf (IfInstanceOf* x);
518 void do_TableSwitch (TableSwitch* x);
519 void do_LookupSwitch (LookupSwitch* x);
520 void do_Return (Return* x);
521 void do_Throw (Throw* x);
522 void do_Base (Base* x);
523 void do_OsrEntry (OsrEntry* x);
524 void do_ExceptionObject(ExceptionObject* x);
525 void do_RoundFP (RoundFP* x);
526 void do_UnsafeGetRaw (UnsafeGetRaw* x);
527 void do_UnsafePutRaw (UnsafePutRaw* x);
528 void do_UnsafeGetObject(UnsafeGetObject* x);
529 void do_UnsafePutObject(UnsafePutObject* x);
530 void do_UnsafeGetAndSetObject(UnsafeGetAndSetObject* x);
531 void do_UnsafePrefetchRead (UnsafePrefetchRead* x);
532 void do_UnsafePrefetchWrite(UnsafePrefetchWrite* x);
533 void do_ProfileCall (ProfileCall* x);
534 void do_ProfileReturnType (ProfileReturnType* x);
535 void do_ProfileInvoke (ProfileInvoke* x);
536 void do_RuntimeCall (RuntimeCall* x);
537 void do_MemBar (MemBar* x);
538 void do_RangeCheckPredicate(RangeCheckPredicate* x);
539 #ifdef ASSERT
540 void do_Assert (Assert* x);
541 #endif
542 };
543
544
545 // Because of a static contained within (for the purpose of iteration
546 // over instructions), it is only valid to have one of these active at
547 // a time
548 class NullCheckEliminator: public ValueVisitor {
549 private:
550 Optimizer* _opt;
551
552 ValueSet* _visitable_instructions; // Visit each instruction only once per basic block
553 BlockList* _work_list; // Basic blocks to visit
554
555 bool visitable(Value x) {
556 assert(_visitable_instructions != NULL, "check");
557 return _visitable_instructions->contains(x);
558 }
559 void mark_visited(Value x) {
560 assert(_visitable_instructions != NULL, "check");
561 _visitable_instructions->remove(x);
562 }
563 void mark_visitable(Value x) {
564 assert(_visitable_instructions != NULL, "check");
565 _visitable_instructions->put(x);
566 }
567 void clear_visitable_state() {
568 assert(_visitable_instructions != NULL, "check");
569 _visitable_instructions->clear();
570 }
571
572 ValueSet* _set; // current state, propagated to subsequent BlockBegins
573 ValueSetList _block_states; // BlockBegin null-check states for all processed blocks
574 NullCheckVisitor _visitor;
575 NullCheck* _last_explicit_null_check;
576
577 bool set_contains(Value x) { assert(_set != NULL, "check"); return _set->contains(x); }
578 void set_put (Value x) { assert(_set != NULL, "check"); _set->put(x); }
579 void set_remove (Value x) { assert(_set != NULL, "check"); _set->remove(x); }
580
581 BlockList* work_list() { return _work_list; }
582
583 void iterate_all();
584 void iterate_one(BlockBegin* block);
585
586 ValueSet* state() { return _set; }
587 void set_state_from (ValueSet* state) { _set->set_from(state); }
588 ValueSet* state_for (BlockBegin* block) { return _block_states[block->block_id()]; }
589 void set_state_for (BlockBegin* block, ValueSet* stack) { _block_states[block->block_id()] = stack; }
590 // Returns true if caused a change in the block's state.
591 bool merge_state_for(BlockBegin* block,
592 ValueSet* incoming_state);
593
594 public:
595 // constructor
596 NullCheckEliminator(Optimizer* opt)
597 : _opt(opt)
598 , _set(new ValueSet())
599 , _last_explicit_null_check(NULL)
600 , _block_states(BlockBegin::number_of_blocks(), NULL)
601 , _work_list(new BlockList()) {
602 _visitable_instructions = new ValueSet();
603 _visitor.set_eliminator(this);
604 CompileLog* log = _opt->ir()->compilation()->log();
605 if (log != NULL)
606 log->set_context("optimize name='null_check_elimination'");
607 }
608
609 ~NullCheckEliminator() {
610 CompileLog* log = _opt->ir()->compilation()->log();
611 if (log != NULL)
612 log->clear_context(); // skip marker if nothing was printed
613 }
614
615 Optimizer* opt() { return _opt; }
616 IR* ir () { return opt()->ir(); }
617
618 // Process a graph
619 void iterate(BlockBegin* root);
620
621 void visit(Value* f);
622
623 // In some situations (like NullCheck(x); getfield(x)) the debug
624 // information from the explicit NullCheck can be used to populate
625 // the getfield, even if the two instructions are in different
626 // scopes; this allows implicit null checks to be used but the
627 // correct exception information to be generated. We must clear the
628 // last-traversed NullCheck when we reach a potentially-exception-
629 // throwing instruction, as well as in some other cases.
630 void set_last_explicit_null_check(NullCheck* check) { _last_explicit_null_check = check; }
631 NullCheck* last_explicit_null_check() { return _last_explicit_null_check; }
632 Value last_explicit_null_check_obj() { return (_last_explicit_null_check
633 ? _last_explicit_null_check->obj()
634 : NULL); }
635 NullCheck* consume_last_explicit_null_check() {
636 _last_explicit_null_check->unpin(Instruction::PinExplicitNullCheck);
637 _last_explicit_null_check->set_can_trap(false);
638 return _last_explicit_null_check;
639 }
640 void clear_last_explicit_null_check() { _last_explicit_null_check = NULL; }
641
642 // Handlers for relevant instructions
643 // (separated out from NullCheckVisitor for clarity)
644
645 // The basic contract is that these must leave the instruction in
646 // the desired state; must not assume anything about the state of
647 // the instruction. We make multiple passes over some basic blocks
648 // and the last pass is the only one whose result is valid.
649 void handle_AccessField (AccessField* x);
650 void handle_ArrayLength (ArrayLength* x);
651 void handle_LoadIndexed (LoadIndexed* x);
652 void handle_StoreIndexed (StoreIndexed* x);
653 void handle_NullCheck (NullCheck* x);
654 void handle_Invoke (Invoke* x);
655 void handle_NewInstance (NewInstance* x);
656 void handle_NewArray (NewArray* x);
657 void handle_AccessMonitor (AccessMonitor* x);
658 void handle_Intrinsic (Intrinsic* x);
659 void handle_ExceptionObject (ExceptionObject* x);
660 void handle_Phi (Phi* x);
661 void handle_ProfileCall (ProfileCall* x);
662 void handle_ProfileReturnType (ProfileReturnType* x);
663 };
664
665
666 // NEEDS_CLEANUP
667 // There may be other instructions which need to clear the last
668 // explicit null check. Anything across which we can not hoist the
669 // debug information for a NullCheck instruction must clear it. It
670 // might be safer to pattern match "NullCheck ; {AccessField,
671 // ArrayLength, LoadIndexed}" but it is more easily structured this way.
672 // Should test to see performance hit of clearing it for all handlers
673 // with empty bodies below. If it is negligible then we should leave
674 // that in for safety, otherwise should think more about it.
675 void NullCheckVisitor::do_Phi (Phi* x) { nce()->handle_Phi(x); }
676 void NullCheckVisitor::do_Local (Local* x) {}
677 void NullCheckVisitor::do_Constant (Constant* x) { /* FIXME: handle object constants */ }
678 void NullCheckVisitor::do_LoadField (LoadField* x) { nce()->handle_AccessField(x); }
679 void NullCheckVisitor::do_StoreField (StoreField* x) { nce()->handle_AccessField(x); }
680 void NullCheckVisitor::do_ArrayLength (ArrayLength* x) { nce()->handle_ArrayLength(x); }
681 void NullCheckVisitor::do_LoadIndexed (LoadIndexed* x) { nce()->handle_LoadIndexed(x); }
682 void NullCheckVisitor::do_StoreIndexed (StoreIndexed* x) { nce()->handle_StoreIndexed(x); }
683 void NullCheckVisitor::do_NegateOp (NegateOp* x) {}
684 void NullCheckVisitor::do_ArithmeticOp (ArithmeticOp* x) { if (x->can_trap()) nce()->clear_last_explicit_null_check(); }
685 void NullCheckVisitor::do_ShiftOp (ShiftOp* x) {}
686 void NullCheckVisitor::do_LogicOp (LogicOp* x) {}
687 void NullCheckVisitor::do_CompareOp (CompareOp* x) {}
688 void NullCheckVisitor::do_IfOp (IfOp* x) {}
689 void NullCheckVisitor::do_Convert (Convert* x) {}
690 void NullCheckVisitor::do_NullCheck (NullCheck* x) { nce()->handle_NullCheck(x); }
691 void NullCheckVisitor::do_TypeCast (TypeCast* x) {}
692 void NullCheckVisitor::do_Invoke (Invoke* x) { nce()->handle_Invoke(x); }
693 void NullCheckVisitor::do_NewInstance (NewInstance* x) { nce()->handle_NewInstance(x); }
694 void NullCheckVisitor::do_NewTypeArray (NewTypeArray* x) { nce()->handle_NewArray(x); }
695 void NullCheckVisitor::do_NewObjectArray (NewObjectArray* x) { nce()->handle_NewArray(x); }
696 void NullCheckVisitor::do_NewMultiArray (NewMultiArray* x) { nce()->handle_NewArray(x); }
697 void NullCheckVisitor::do_CheckCast (CheckCast* x) { nce()->clear_last_explicit_null_check(); }
698 void NullCheckVisitor::do_InstanceOf (InstanceOf* x) {}
699 void NullCheckVisitor::do_MonitorEnter (MonitorEnter* x) { nce()->handle_AccessMonitor(x); }
700 void NullCheckVisitor::do_MonitorExit (MonitorExit* x) { nce()->handle_AccessMonitor(x); }
701 void NullCheckVisitor::do_Intrinsic (Intrinsic* x) { nce()->handle_Intrinsic(x); }
702 void NullCheckVisitor::do_BlockBegin (BlockBegin* x) {}
703 void NullCheckVisitor::do_Goto (Goto* x) {}
704 void NullCheckVisitor::do_If (If* x) {}
705 void NullCheckVisitor::do_IfInstanceOf (IfInstanceOf* x) {}
706 void NullCheckVisitor::do_TableSwitch (TableSwitch* x) {}
707 void NullCheckVisitor::do_LookupSwitch (LookupSwitch* x) {}
708 void NullCheckVisitor::do_Return (Return* x) {}
709 void NullCheckVisitor::do_Throw (Throw* x) { nce()->clear_last_explicit_null_check(); }
710 void NullCheckVisitor::do_Base (Base* x) {}
711 void NullCheckVisitor::do_OsrEntry (OsrEntry* x) {}
712 void NullCheckVisitor::do_ExceptionObject(ExceptionObject* x) { nce()->handle_ExceptionObject(x); }
713 void NullCheckVisitor::do_RoundFP (RoundFP* x) {}
714 void NullCheckVisitor::do_UnsafeGetRaw (UnsafeGetRaw* x) {}
715 void NullCheckVisitor::do_UnsafePutRaw (UnsafePutRaw* x) {}
716 void NullCheckVisitor::do_UnsafeGetObject(UnsafeGetObject* x) {}
717 void NullCheckVisitor::do_UnsafePutObject(UnsafePutObject* x) {}
718 void NullCheckVisitor::do_UnsafeGetAndSetObject(UnsafeGetAndSetObject* x) {}
719 void NullCheckVisitor::do_UnsafePrefetchRead (UnsafePrefetchRead* x) {}
720 void NullCheckVisitor::do_UnsafePrefetchWrite(UnsafePrefetchWrite* x) {}
721 void NullCheckVisitor::do_ProfileCall (ProfileCall* x) { nce()->clear_last_explicit_null_check();
722 nce()->handle_ProfileCall(x); }
723 void NullCheckVisitor::do_ProfileReturnType (ProfileReturnType* x) { nce()->handle_ProfileReturnType(x); }
724 void NullCheckVisitor::do_ProfileInvoke (ProfileInvoke* x) {}
725 void NullCheckVisitor::do_RuntimeCall (RuntimeCall* x) {}
726 void NullCheckVisitor::do_MemBar (MemBar* x) {}
727 void NullCheckVisitor::do_RangeCheckPredicate(RangeCheckPredicate* x) {}
728 #ifdef ASSERT
729 void NullCheckVisitor::do_Assert (Assert* x) {}
730 #endif
731
732 void NullCheckEliminator::visit(Value* p) {
733 assert(*p != NULL, "should not find NULL instructions");
734 if (visitable(*p)) {
735 mark_visited(*p);
736 (*p)->visit(&_visitor);
737 }
738 }
739
740 bool NullCheckEliminator::merge_state_for(BlockBegin* block, ValueSet* incoming_state) {
741 ValueSet* state = state_for(block);
742 if (state == NULL) {
743 state = incoming_state->copy();
744 set_state_for(block, state);
745 return true;
746 } else {
747 bool changed = state->set_intersect(incoming_state);
748 if (PrintNullCheckElimination && changed) {
749 tty->print_cr("Block %d's null check state changed", block->block_id());
750 }
751 return changed;
752 }
753 }
754
755
756 void NullCheckEliminator::iterate_all() {
757 while (work_list()->length() > 0) {
758 iterate_one(work_list()->pop());
759 }
760 }
761
762
763 void NullCheckEliminator::iterate_one(BlockBegin* block) {
764 clear_visitable_state();
765 // clear out an old explicit null checks
766 set_last_explicit_null_check(NULL);
767
768 if (PrintNullCheckElimination) {
769 tty->print_cr(" ...iterating block %d in null check elimination for %s::%s%s",
770 block->block_id(),
771 ir()->method()->holder()->name()->as_utf8(),
772 ir()->method()->name()->as_utf8(),
773 ir()->method()->signature()->as_symbol()->as_utf8());
774 }
775
776 // Create new state if none present (only happens at root)
777 if (state_for(block) == NULL) {
778 ValueSet* tmp_state = new ValueSet();
779 set_state_for(block, tmp_state);
780 // Initial state is that local 0 (receiver) is non-null for
781 // non-static methods
782 ValueStack* stack = block->state();
783 IRScope* scope = stack->scope();
784 ciMethod* method = scope->method();
785 if (!method->is_static()) {
786 Local* local0 = stack->local_at(0)->as_Local();
787 assert(local0 != NULL, "must be");
788 assert(local0->type() == objectType, "invalid type of receiver");
789
790 if (local0 != NULL) {
791 // Local 0 is used in this scope
792 tmp_state->put(local0);
793 if (PrintNullCheckElimination) {
794 tty->print_cr("Local 0 (value %d) proven non-null upon entry", local0->id());
795 }
796 }
797 }
798 }
799
800 // Must copy block's state to avoid mutating it during iteration
801 // through the block -- otherwise "not-null" states can accidentally
802 // propagate "up" through the block during processing of backward
803 // branches and algorithm is incorrect (and does not converge)
804 set_state_from(state_for(block));
805
806 // allow visiting of Phis belonging to this block
807 for_each_phi_fun(block, phi,
808 mark_visitable(phi);
809 );
810
811 BlockEnd* e = block->end();
812 assert(e != NULL, "incomplete graph");
813 int i;
814
815 // Propagate the state before this block into the exception
816 // handlers. They aren't true successors since we aren't guaranteed
817 // to execute the whole block before executing them. Also putting
818 // them on first seems to help reduce the amount of iteration to
819 // reach a fixed point.
820 for (i = 0; i < block->number_of_exception_handlers(); i++) {
821 BlockBegin* next = block->exception_handler_at(i);
822 if (merge_state_for(next, state())) {
823 if (!work_list()->contains(next)) {
824 work_list()->push(next);
825 }
826 }
827 }
828
829 // Iterate through block, updating state.
830 for (Instruction* instr = block; instr != NULL; instr = instr->next()) {
831 // Mark instructions in this block as visitable as they are seen
832 // in the instruction list. This keeps the iteration from
833 // visiting instructions which are references in other blocks or
834 // visiting instructions more than once.
835 mark_visitable(instr);
836 if (instr->is_pinned() || instr->can_trap() || (instr->as_NullCheck() != NULL)) {
837 mark_visited(instr);
838 instr->input_values_do(this);
839 instr->visit(&_visitor);
840 }
841 }
842
843 // Propagate state to successors if necessary
844 for (i = 0; i < e->number_of_sux(); i++) {
845 BlockBegin* next = e->sux_at(i);
846 if (merge_state_for(next, state())) {
847 if (!work_list()->contains(next)) {
848 work_list()->push(next);
849 }
850 }
851 }
852 }
853
854
855 void NullCheckEliminator::iterate(BlockBegin* block) {
856 work_list()->push(block);
857 iterate_all();
858 }
859
860 void NullCheckEliminator::handle_AccessField(AccessField* x) {
861 if (x->is_static()) {
862 if (x->as_LoadField() != NULL) {
863 // If the field is a non-null static final object field (as is
864 // often the case for sun.misc.Unsafe), put this LoadField into
865 // the non-null map
866 ciField* field = x->field();
867 if (field->is_constant()) {
868 ciConstant field_val = field->constant_value();
869 BasicType field_type = field_val.basic_type();
870 if (field_type == T_OBJECT || field_type == T_ARRAY) {
871 ciObject* obj_val = field_val.as_object();
872 if (!obj_val->is_null_object()) {
873 if (PrintNullCheckElimination) {
874 tty->print_cr("AccessField %d proven non-null by static final non-null oop check",
875 x->id());
876 }
877 set_put(x);
878 }
879 }
880 }
881 }
882 // Be conservative
883 clear_last_explicit_null_check();
884 return;
885 }
886
887 Value obj = x->obj();
888 if (set_contains(obj)) {
889 // Value is non-null => update AccessField
890 if (last_explicit_null_check_obj() == obj && !x->needs_patching()) {
891 x->set_explicit_null_check(consume_last_explicit_null_check());
892 x->set_needs_null_check(true);
893 if (PrintNullCheckElimination) {
894 tty->print_cr("Folded NullCheck %d into AccessField %d's null check for value %d",
895 x->explicit_null_check()->id(), x->id(), obj->id());
896 }
897 } else {
898 x->set_explicit_null_check(NULL);
899 x->set_needs_null_check(false);
900 if (PrintNullCheckElimination) {
901 tty->print_cr("Eliminated AccessField %d's null check for value %d", x->id(), obj->id());
902 }
903 }
904 } else {
905 set_put(obj);
906 if (PrintNullCheckElimination) {
907 tty->print_cr("AccessField %d of value %d proves value to be non-null", x->id(), obj->id());
908 }
909 // Ensure previous passes do not cause wrong state
910 x->set_needs_null_check(true);
911 x->set_explicit_null_check(NULL);
912 }
913 clear_last_explicit_null_check();
914 }
915
916
917 void NullCheckEliminator::handle_ArrayLength(ArrayLength* x) {
918 Value array = x->array();
919 if (set_contains(array)) {
920 // Value is non-null => update AccessArray
921 if (last_explicit_null_check_obj() == array) {
922 x->set_explicit_null_check(consume_last_explicit_null_check());
923 x->set_needs_null_check(true);
924 if (PrintNullCheckElimination) {
925 tty->print_cr("Folded NullCheck %d into ArrayLength %d's null check for value %d",
926 x->explicit_null_check()->id(), x->id(), array->id());
927 }
928 } else {
929 x->set_explicit_null_check(NULL);
930 x->set_needs_null_check(false);
931 if (PrintNullCheckElimination) {
932 tty->print_cr("Eliminated ArrayLength %d's null check for value %d", x->id(), array->id());
933 }
934 }
935 } else {
936 set_put(array);
937 if (PrintNullCheckElimination) {
938 tty->print_cr("ArrayLength %d of value %d proves value to be non-null", x->id(), array->id());
939 }
940 // Ensure previous passes do not cause wrong state
941 x->set_needs_null_check(true);
942 x->set_explicit_null_check(NULL);
943 }
944 clear_last_explicit_null_check();
945 }
946
947
948 void NullCheckEliminator::handle_LoadIndexed(LoadIndexed* x) {
949 Value array = x->array();
950 if (set_contains(array)) {
951 // Value is non-null => update AccessArray
952 if (last_explicit_null_check_obj() == array) {
953 x->set_explicit_null_check(consume_last_explicit_null_check());
954 x->set_needs_null_check(true);
955 if (PrintNullCheckElimination) {
956 tty->print_cr("Folded NullCheck %d into LoadIndexed %d's null check for value %d",
957 x->explicit_null_check()->id(), x->id(), array->id());
958 }
959 } else {
960 x->set_explicit_null_check(NULL);
961 x->set_needs_null_check(false);
962 if (PrintNullCheckElimination) {
963 tty->print_cr("Eliminated LoadIndexed %d's null check for value %d", x->id(), array->id());
964 }
965 }
966 } else {
967 set_put(array);
968 if (PrintNullCheckElimination) {
969 tty->print_cr("LoadIndexed %d of value %d proves value to be non-null", x->id(), array->id());
970 }
971 // Ensure previous passes do not cause wrong state
972 x->set_needs_null_check(true);
973 x->set_explicit_null_check(NULL);
974 }
975 clear_last_explicit_null_check();
976 }
977
978
979 void NullCheckEliminator::handle_StoreIndexed(StoreIndexed* x) {
980 Value array = x->array();
981 if (set_contains(array)) {
982 // Value is non-null => update AccessArray
983 if (PrintNullCheckElimination) {
984 tty->print_cr("Eliminated StoreIndexed %d's null check for value %d", x->id(), array->id());
985 }
986 x->set_needs_null_check(false);
987 } else {
988 set_put(array);
989 if (PrintNullCheckElimination) {
990 tty->print_cr("StoreIndexed %d of value %d proves value to be non-null", x->id(), array->id());
991 }
992 // Ensure previous passes do not cause wrong state
993 x->set_needs_null_check(true);
994 }
995 clear_last_explicit_null_check();
996 }
997
998
999 void NullCheckEliminator::handle_NullCheck(NullCheck* x) {
1000 Value obj = x->obj();
1001 if (set_contains(obj)) {
1002 // Already proven to be non-null => this NullCheck is useless
1003 if (PrintNullCheckElimination) {
1004 tty->print_cr("Eliminated NullCheck %d for value %d", x->id(), obj->id());
1005 }
1006 // Don't unpin since that may shrink obj's live range and make it unavailable for debug info.
1007 // The code generator won't emit LIR for a NullCheck that cannot trap.
1008 x->set_can_trap(false);
1009 } else {
1010 // May be null => add to map and set last explicit NullCheck
1011 x->set_can_trap(true);
1012 // make sure it's pinned if it can trap
1013 x->pin(Instruction::PinExplicitNullCheck);
1014 set_put(obj);
1015 set_last_explicit_null_check(x);
1016 if (PrintNullCheckElimination) {
1017 tty->print_cr("NullCheck %d of value %d proves value to be non-null", x->id(), obj->id());
1018 }
1019 }
1020 }
1021
1022
1023 void NullCheckEliminator::handle_Invoke(Invoke* x) {
1024 if (!x->has_receiver()) {
1025 // Be conservative
1026 clear_last_explicit_null_check();
1027 return;
1028 }
1029
1030 Value recv = x->receiver();
1031 if (!set_contains(recv)) {
1032 set_put(recv);
1033 if (PrintNullCheckElimination) {
1034 tty->print_cr("Invoke %d of value %d proves value to be non-null", x->id(), recv->id());
1035 }
1036 }
1037 clear_last_explicit_null_check();
1038 }
1039
1040
1041 void NullCheckEliminator::handle_NewInstance(NewInstance* x) {
1042 set_put(x);
1043 if (PrintNullCheckElimination) {
1044 tty->print_cr("NewInstance %d is non-null", x->id());
1045 }
1046 }
1047
1048
1049 void NullCheckEliminator::handle_NewArray(NewArray* x) {
1050 set_put(x);
1051 if (PrintNullCheckElimination) {
1052 tty->print_cr("NewArray %d is non-null", x->id());
1053 }
1054 }
1055
1056
1057 void NullCheckEliminator::handle_ExceptionObject(ExceptionObject* x) {
1058 set_put(x);
1059 if (PrintNullCheckElimination) {
1060 tty->print_cr("ExceptionObject %d is non-null", x->id());
1061 }
1062 }
1063
1064
1065 void NullCheckEliminator::handle_AccessMonitor(AccessMonitor* x) {
1066 Value obj = x->obj();
1067 if (set_contains(obj)) {
1068 // Value is non-null => update AccessMonitor
1069 if (PrintNullCheckElimination) {
1070 tty->print_cr("Eliminated AccessMonitor %d's null check for value %d", x->id(), obj->id());
1071 }
1072 x->set_needs_null_check(false);
1073 } else {
1074 set_put(obj);
1075 if (PrintNullCheckElimination) {
1076 tty->print_cr("AccessMonitor %d of value %d proves value to be non-null", x->id(), obj->id());
1077 }
1078 // Ensure previous passes do not cause wrong state
1079 x->set_needs_null_check(true);
1080 }
1081 clear_last_explicit_null_check();
1082 }
1083
1084
1085 void NullCheckEliminator::handle_Intrinsic(Intrinsic* x) {
1086 if (!x->has_receiver()) {
1087 if (x->id() == vmIntrinsics::_arraycopy) {
1088 for (int i = 0; i < x->number_of_arguments(); i++) {
1089 x->set_arg_needs_null_check(i, !set_contains(x->argument_at(i)));
1090 }
1091 }
1092
1093 // Be conservative
1094 clear_last_explicit_null_check();
1095 return;
1096 }
1097
1098 Value recv = x->receiver();
1099 if (set_contains(recv)) {
1100 // Value is non-null => update Intrinsic
1101 if (PrintNullCheckElimination) {
1102 tty->print_cr("Eliminated Intrinsic %d's null check for value %d", x->id(), recv->id());
1103 }
1104 x->set_needs_null_check(false);
1105 } else {
1106 set_put(recv);
1107 if (PrintNullCheckElimination) {
1108 tty->print_cr("Intrinsic %d of value %d proves value to be non-null", x->id(), recv->id());
1109 }
1110 // Ensure previous passes do not cause wrong state
1111 x->set_needs_null_check(true);
1112 }
1113 clear_last_explicit_null_check();
1114 }
1115
1116
1117 void NullCheckEliminator::handle_Phi(Phi* x) {
1118 int i;
1119 bool all_non_null = true;
1120 if (x->is_illegal()) {
1121 all_non_null = false;
1122 } else {
1123 for (i = 0; i < x->operand_count(); i++) {
1124 Value input = x->operand_at(i);
1125 if (!set_contains(input)) {
1126 all_non_null = false;
1127 }
1128 }
1129 }
1130
1131 if (all_non_null) {
1132 // Value is non-null => update Phi
1133 if (PrintNullCheckElimination) {
1134 tty->print_cr("Eliminated Phi %d's null check for phifun because all inputs are non-null", x->id());
1135 }
1136 x->set_needs_null_check(false);
1137 } else if (set_contains(x)) {
1138 set_remove(x);
1139 }
1140 }
1141
1142 void NullCheckEliminator::handle_ProfileCall(ProfileCall* x) {
1143 for (int i = 0; i < x->nb_profiled_args(); i++) {
1144 x->set_arg_needs_null_check(i, !set_contains(x->profiled_arg_at(i)));
1145 }
1146 }
1147
1148 void NullCheckEliminator::handle_ProfileReturnType(ProfileReturnType* x) {
1149 x->set_needs_null_check(!set_contains(x->ret()));
1150 }
1151
1152 void Optimizer::eliminate_null_checks() {
1153 ResourceMark rm;
1154
1155 NullCheckEliminator nce(this);
1156
1157 if (PrintNullCheckElimination) {
1158 tty->print_cr("Starting null check elimination for method %s::%s%s",
1159 ir()->method()->holder()->name()->as_utf8(),
1160 ir()->method()->name()->as_utf8(),
1161 ir()->method()->signature()->as_symbol()->as_utf8());
1162 }
1163
1164 // Apply to graph
1165 nce.iterate(ir()->start());
1166
1167 // walk over the graph looking for exception
1168 // handlers and iterate over them as well
1169 int nblocks = BlockBegin::number_of_blocks();
1170 BlockList blocks(nblocks);
1171 boolArray visited_block(nblocks, false);
1172
1173 blocks.push(ir()->start());
1174 visited_block[ir()->start()->block_id()] = true;
1175 for (int i = 0; i < blocks.length(); i++) {
1176 BlockBegin* b = blocks[i];
1177 // exception handlers need to be treated as additional roots
1178 for (int e = b->number_of_exception_handlers(); e-- > 0; ) {
1179 BlockBegin* excp = b->exception_handler_at(e);
1180 int id = excp->block_id();
1181 if (!visited_block[id]) {
1182 blocks.push(excp);
1183 visited_block[id] = true;
1184 nce.iterate(excp);
1185 }
1186 }
1187 // traverse successors
1188 BlockEnd *end = b->end();
1189 for (int s = end->number_of_sux(); s-- > 0; ) {
1190 BlockBegin* next = end->sux_at(s);
1191 int id = next->block_id();
1192 if (!visited_block[id]) {
1193 blocks.push(next);
1194 visited_block[id] = true;
1195 }
1196 }
1197 }
1198
1199
1200 if (PrintNullCheckElimination) {
1201 tty->print_cr("Done with null check elimination for method %s::%s%s",
1202 ir()->method()->holder()->name()->as_utf8(),
1203 ir()->method()->name()->as_utf8(),
1204 ir()->method()->signature()->as_symbol()->as_utf8());
1205 }
1206 }