Mercurial > jdk8-mips64-public > hotspot / file comparison

comparison: src/share/vm/c1/c1_RangeCheckElimination.cpp

src/share/vm/c1/c1_RangeCheckElimination.cpp

changeset 4860
46f6f063b272
child 4869
d595e8ddadd9
equal deleted inserted replaced
4780:98f3af397705 4860:46f6f063b272
1 /*
2 * Copyright (c) 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_ValueStack.hpp"
27 #include "c1/c1_RangeCheckElimination.hpp"
28 #include "c1/c1_IR.hpp"
29 #include "c1/c1_Canonicalizer.hpp"
30 #include "c1/c1_ValueMap.hpp"
31 #include "ci/ciMethodData.hpp"
32 #include "runtime/deoptimization.hpp"
33
34 // Macros for the Trace and the Assertion flag
35 #ifdef ASSERT
36 #define TRACE_RANGE_CHECK_ELIMINATION(code) if (TraceRangeCheckElimination) { code; }
37 #define ASSERT_RANGE_CHECK_ELIMINATION(code) if (AssertRangeCheckElimination) { code; }
38 #define TRACE_OR_ASSERT_RANGE_CHECK_ELIMINATION(code) if (TraceRangeCheckElimination || AssertRangeCheckElimination) { code; }
39 #else
40 #define TRACE_RANGE_CHECK_ELIMINATION(code)
41 #define ASSERT_RANGE_CHECK_ELIMINATION(code)
42 #define TRACE_OR_ASSERT_RANGE_CHECK_ELIMINATION(code)
43 #endif
44
45 // Entry point for the optimization
46 void RangeCheckElimination::eliminate(IR *ir) {
47 bool do_elimination = ir->compilation()->has_access_indexed();
48 ASSERT_RANGE_CHECK_ELIMINATION(do_elimination = true);
49 if (do_elimination) {
50 RangeCheckEliminator rce(ir);
51 }
52 }
53
54 // Constructor
55 RangeCheckEliminator::RangeCheckEliminator(IR *ir) :
56 _bounds(Instruction::number_of_instructions(), NULL),
57 _access_indexed_info(Instruction::number_of_instructions(), NULL)
58 {
59 _visitor.set_range_check_eliminator(this);
60 _ir = ir;
61 _number_of_instructions = Instruction::number_of_instructions();
62 _optimistic = ir->compilation()->is_optimistic();
63
64 TRACE_RANGE_CHECK_ELIMINATION(
65 tty->print_cr("");
66 tty->print_cr("Range check elimination");
67 ir->method()->print_name(tty);
68 tty->print_cr("");
69 );
70
71 TRACE_RANGE_CHECK_ELIMINATION(
72 tty->print_cr("optimistic=%d", (int)_optimistic);
73 );
74
75 #ifdef ASSERT
76 // Verifies several conditions that must be true on the IR-input. Only used for debugging purposes.
77 TRACE_RANGE_CHECK_ELIMINATION(
78 tty->print_cr("Verification of IR . . .");
79 );
80 Verification verification(ir);
81 #endif
82
83 // Set process block flags
84 // Optimization so a blocks is only processed if it contains an access indexed instruction or if
85 // one of its children in the dominator tree contains an access indexed instruction.
86 set_process_block_flags(ir->start());
87
88 // Pass over instructions in the dominator tree
89 TRACE_RANGE_CHECK_ELIMINATION(
90 tty->print_cr("Starting pass over dominator tree . . .")
91 );
92 calc_bounds(ir->start(), NULL);
93
94 TRACE_RANGE_CHECK_ELIMINATION(
95 tty->print_cr("Finished!")
96 );
97 }
98
99 // Instruction specific work for some instructions
100 // Constant
101 void RangeCheckEliminator::Visitor::do_Constant(Constant *c) {
102 IntConstant *ic = c->type()->as_IntConstant();
103 if (ic != NULL) {
104 int value = ic->value();
105 _bound = new Bound(value, NULL, value, NULL);
106 }
107 }
108
109 // LogicOp
110 void RangeCheckEliminator::Visitor::do_LogicOp(LogicOp *lo) {
111 if (lo->type()->as_IntType() && lo->op() == Bytecodes::_iand && (lo->x()->as_Constant() || lo->y()->as_Constant())) {
112 int constant = 0;
113 Constant *c = lo->x()->as_Constant();
114 if (c != NULL) {
115 constant = c->type()->as_IntConstant()->value();
116 } else {
117 constant = lo->y()->as_Constant()->type()->as_IntConstant()->value();
118 }
119 if (constant >= 0) {
120 _bound = new Bound(0, NULL, constant, NULL);
121 }
122 }
123 }
124
125 // Phi
126 void RangeCheckEliminator::Visitor::do_Phi(Phi *phi) {
127 if (!phi->type()->as_IntType() && !phi->type()->as_ObjectType()) return;
128
129 BlockBegin *block = phi->block();
130 int op_count = phi->operand_count();
131 bool has_upper = true;
132 bool has_lower = true;
133 assert(phi, "Phi must not be null");
134 Bound *bound = NULL;
135
136 // TODO: support more difficult phis
137 for (int i=0; i<op_count; i++) {
138 Value v = phi->operand_at(i);
139
140 if (v == phi) continue;
141
142 // Check if instruction is connected with phi itself
143 Op2 *op2 = v->as_Op2();
144 if (op2 != NULL) {
145 Value x = op2->x();
146 Value y = op2->y();
147 if ((x == phi || y == phi)) {
148 Value other = x;
149 if (other == phi) {
150 other = y;
151 }
152 ArithmeticOp *ao = v->as_ArithmeticOp();
153 if (ao != NULL && ao->op() == Bytecodes::_iadd) {
154 assert(ao->op() == Bytecodes::_iadd, "Has to be add!");
155 if (ao->type()->as_IntType()) {
156 Constant *c = other->as_Constant();
157 if (c != NULL) {
158 assert(c->type()->as_IntConstant(), "Constant has to be of type integer");
159 int value = c->type()->as_IntConstant()->value();
160 if (value == 1) {
161 has_upper = false;
162 } else if (value > 1) {
163 // Overflow not guaranteed
164 has_upper = false;
165 has_lower = false;
166 } else if (value < 0) {
167 has_lower = false;
168 }
169 continue;
170 }
171 }
172 }
173 }
174 }
175
176 // No connection -> new bound
177 Bound *v_bound = _rce->get_bound(v);
178 Bound *cur_bound;
179 int cur_constant = 0;
180 Value cur_value = v;
181
182 if (v->type()->as_IntConstant()) {
183 cur_constant = v->type()->as_IntConstant()->value();
184 cur_value = NULL;
185 }
186 if (!v_bound->has_upper() || !v_bound->has_lower()) {
187 cur_bound = new Bound(cur_constant, cur_value, cur_constant, cur_value);
188 } else {
189 cur_bound = v_bound;
190 }
191 if (cur_bound) {
192 if (!bound) {
193 bound = cur_bound->copy();
194 } else {
195 bound->or_op(cur_bound);
196 }
197 } else {
198 // No bound!
199 bound = NULL;
200 break;
201 }
202 }
203
204 if (bound) {
205 if (!has_upper) {
206 bound->remove_upper();
207 }
208 if (!has_lower) {
209 bound->remove_lower();
210 }
211 _bound = bound;
212 } else {
213 _bound = new Bound();
214 }
215 }
216
217
218 // ArithmeticOp
219 void RangeCheckEliminator::Visitor::do_ArithmeticOp(ArithmeticOp *ao) {
220 Value x = ao->x();
221 Value y = ao->y();
222
223 if (ao->op() == Bytecodes::_irem) {
224 Bound* x_bound = _rce->get_bound(x);
225 Bound* y_bound = _rce->get_bound(y);
226 if (x_bound->lower() >= 0 && x_bound->lower_instr() == NULL && y->as_ArrayLength() != NULL) {
227 _bound = new Bound(0, NULL, -1, y);
228 } else {
229 _bound = new Bound();
230 }
231 } else if (!x->as_Constant() || !y->as_Constant()) {
232 assert(!x->as_Constant() || !y->as_Constant(), "One of the operands must be non-constant!");
233 if (((x->as_Constant() || y->as_Constant()) && (ao->op() == Bytecodes::_iadd)) || (y->as_Constant() && ao->op() == Bytecodes::_isub)) {
234 assert(ao->op() == Bytecodes::_iadd || ao->op() == Bytecodes::_isub, "Operand must be iadd or isub");
235
236 if (y->as_Constant()) {
237 Value tmp = x;
238 x = y;
239 y = tmp;
240 }
241 assert(x->as_Constant()->type()->as_IntConstant(), "Constant must be int constant!");
242
243 // Constant now in x
244 int const_value = x->as_Constant()->type()->as_IntConstant()->value();
245 if (ao->op() == Bytecodes::_iadd || const_value != min_jint) {
246 if (ao->op() == Bytecodes::_isub) {
247 const_value = -const_value;
248 }
249
250 Bound * bound = _rce->get_bound(y);
251 if (bound->has_upper() && bound->has_lower()) {
252 int new_lower = bound->lower() + const_value;
253 jlong new_lowerl = ((jlong)bound->lower()) + const_value;
254 int new_upper = bound->upper() + const_value;
255 jlong new_upperl = ((jlong)bound->upper()) + const_value;
256
257 if (((jlong)new_lower) == new_lowerl && ((jlong)new_upper == new_upperl)) {
258 Bound *newBound = new Bound(new_lower, bound->lower_instr(), new_upper, bound->upper_instr());
259 _bound = newBound;
260 } else {
261 // overflow
262 _bound = new Bound();
263 }
264 } else {
265 _bound = new Bound();
266 }
267 } else {
268 _bound = new Bound();
269 }
270 } else {
271 Bound *bound = _rce->get_bound(x);
272 if (ao->op() == Bytecodes::_isub) {
273 if (bound->lower_instr() == y) {
274 _bound = new Bound(Instruction::geq, NULL, bound->lower());
275 } else {
276 _bound = new Bound();
277 }
278 } else {
279 _bound = new Bound();
280 }
281 }
282 }
283 }
284
285 // IfOp
286 void RangeCheckEliminator::Visitor::do_IfOp(IfOp *ifOp)
287 {
288 if (ifOp->tval()->type()->as_IntConstant() && ifOp->fval()->type()->as_IntConstant()) {
289 int min = ifOp->tval()->type()->as_IntConstant()->value();
290 int max = ifOp->fval()->type()->as_IntConstant()->value();
291 if (min > max) {
292 // min ^= max ^= min ^= max;
293 int tmp = min;
294 min = max;
295 max = tmp;
296 }
297 _bound = new Bound(min, NULL, max, NULL);
298 }
299 }
300
301 // Get bound. Returns the current bound on Value v. Normally this is the topmost element on the bound stack.
302 RangeCheckEliminator::Bound *RangeCheckEliminator::get_bound(Value v) {
303 // Wrong type or NULL -> No bound
304 if (!v || (!v->type()->as_IntType() && !v->type()->as_ObjectType())) return NULL;
305
306 if (!_bounds[v->id()]) {
307 // First (default) bound is calculated
308 // Create BoundStack
309 _bounds[v->id()] = new BoundStack();
310 _visitor.clear_bound();
311 Value visit_value = v;
312 visit_value->visit(&_visitor);
313 Bound *bound = _visitor.bound();
314 if (bound) {
315 _bounds[v->id()]->push(bound);
316 }
317 if (_bounds[v->id()]->length() == 0) {
318 assert(!(v->as_Constant() && v->type()->as_IntConstant()), "constants not handled here");
319 _bounds[v->id()]->push(new Bound());
320 }
321 } else if (_bounds[v->id()]->length() == 0) {
322 // To avoid endless loops, bound is currently in calculation -> nothing known about it
323 return new Bound();
324 }
325
326 // Return bound
327 return _bounds[v->id()]->top();
328 }
329
330 // Update bound
331 void RangeCheckEliminator::update_bound(IntegerStack &pushed, Value v, Instruction::Condition cond, Value value, int constant) {
332 if (cond == Instruction::gtr) {
333 cond = Instruction::geq;
334 constant++;
335 } else if (cond == Instruction::lss) {
336 cond = Instruction::leq;
337 constant--;
338 }
339 Bound *bound = new Bound(cond, value, constant);
340 update_bound(pushed, v, bound);
341 }
342
343 // Checks for loop invariance. Returns true if the instruction is outside of the loop which is identified by loop_header.
344 bool RangeCheckEliminator::loop_invariant(BlockBegin *loop_header, Instruction *instruction) {
345 assert(loop_header, "Loop header must not be null!");
346 if (!instruction) return true;
347 return instruction->dominator_depth() < loop_header->dominator_depth();
348 }
349
350 // Update bound. Pushes a new bound onto the stack. Tries to do a conjunction with the current bound.
351 void RangeCheckEliminator::update_bound(IntegerStack &pushed, Value v, Bound *bound) {
352 if (v->as_Constant()) {
353 // No bound update for constants
354 return;
355 }
356 if (!_bounds[v->id()]) {
357 get_bound(v);
358 assert(_bounds[v->id()], "Now Stack must exist");
359 }
360 Bound *top = NULL;
361 if (_bounds[v->id()]->length() > 0) {
362 top = _bounds[v->id()]->top();
363 }
364 if (top) {
365 bound->and_op(top);
366 }
367 _bounds[v->id()]->push(bound);
368 pushed.append(v->id());
369 }
370
371 // Add instruction + idx for in block motion
372 void RangeCheckEliminator::add_access_indexed_info(InstructionList &indices, int idx, Value instruction, AccessIndexed *ai) {
373 int id = instruction->id();
374 AccessIndexedInfo *aii = _access_indexed_info[id];
375 if (aii == NULL) {
376 aii = new AccessIndexedInfo();
377 _access_indexed_info[id] = aii;
378 indices.append(instruction);
379 aii->_min = idx;
380 aii->_max = idx;
381 aii->_list = new AccessIndexedList();
382 } else if (idx >= aii->_min && idx <= aii->_max) {
383 remove_range_check(ai);
384 return;
385 }
386 aii->_min = MIN2(aii->_min, idx);
387 aii->_max = MAX2(aii->_max, idx);
388 aii->_list->append(ai);
389 }
390
391 // In block motion. Tries to reorder checks in order to reduce some of them.
392 // Example:
393 // a[i] = 0;
394 // a[i+2] = 0;
395 // a[i+1] = 0;
396 // In this example the check for a[i+1] would be considered as unnecessary during the first iteration.
397 // After this i is only checked once for i >= 0 and i+2 < a.length before the first array access. If this
398 // check fails, deoptimization is called.
399 void RangeCheckEliminator::in_block_motion(BlockBegin *block, AccessIndexedList &accessIndexed, InstructionList &arrays) {
400 InstructionList indices;
401
402 // Now iterate over all arrays
403 for (int i=0; i<arrays.length(); i++) {
404 int max_constant = -1;
405 AccessIndexedList list_constant;
406 Value array = arrays.at(i);
407
408 // For all AccessIndexed-instructions in this block concerning the current array.
409 for(int j=0; j<accessIndexed.length(); j++) {
410 AccessIndexed *ai = accessIndexed.at(j);
411 if (ai->array() != array || !ai->check_flag(Instruction::NeedsRangeCheckFlag)) continue;
412
413 Value index = ai->index();
414 Constant *c = index->as_Constant();
415 if (c != NULL) {
416 int constant_value = c->type()->as_IntConstant()->value();
417 if (constant_value >= 0) {
418 if (constant_value <= max_constant) {
419 // No range check needed for this
420 remove_range_check(ai);
421 } else {
422 max_constant = constant_value;
423 list_constant.append(ai);
424 }
425 }
426 } else {
427 int last_integer = 0;
428 Instruction *last_instruction = index;
429 int base = 0;
430 ArithmeticOp *ao = index->as_ArithmeticOp();
431
432 while (ao != NULL && (ao->x()->as_Constant() || ao->y()->as_Constant()) && (ao->op() == Bytecodes::_iadd || ao->op() == Bytecodes::_isub)) {
433 c = ao->y()->as_Constant();
434 Instruction *other = ao->x();
435 if (!c && ao->op() == Bytecodes::_iadd) {
436 c = ao->x()->as_Constant();
437 other = ao->y();
438 }
439
440 if (c) {
441 int value = c->type()->as_IntConstant()->value();
442 if (value != min_jint) {
443 if (ao->op() == Bytecodes::_isub) {
444 value = -value;
445 }
446 base += value;
447 last_integer = base;
448 last_instruction = other;
449 }
450 index = other;
451 } else {
452 break;
453 }
454 ao = index->as_ArithmeticOp();
455 }
456 add_access_indexed_info(indices, last_integer, last_instruction, ai);
457 }
458 }
459
460 // Iterate over all different indices
461 if (_optimistic) {
462 for (int i=0; i<indices.length(); i++) {
463 Instruction *index_instruction = indices.at(i);
464 AccessIndexedInfo *info = _access_indexed_info[index_instruction->id()];
465 assert(info != NULL, "Info must not be null");
466
467 // if idx < 0, max > 0, max + idx may fall between 0 and
468 // length-1 and if min < 0, min + idx may overflow and be >=
469 // 0. The predicate wouldn't trigger but some accesses could
470 // be with a negative index. This test guarantees that for the
471 // min and max value that are kept the predicate can't let
472 // some incorrect accesses happen.
473 bool range_cond = (info->_max < 0 || info->_max + min_jint <= info->_min);
474
475 // Generate code only if more than 2 range checks can be eliminated because of that.
476 // 2 because at least 2 comparisons are done
477 if (info->_list->length() > 2 && range_cond) {
478 AccessIndexed *first = info->_list->at(0);
479 Instruction *insert_position = first->prev();
480 assert(insert_position->next() == first, "prev was calculated");
481 ValueStack *state = first->state_before();
482
483 // Load min Constant
484 Constant *min_constant = NULL;
485 if (info->_min != 0) {
486 min_constant = new Constant(new IntConstant(info->_min));
487 NOT_PRODUCT(min_constant->set_printable_bci(first->printable_bci()));
488 insert_position = insert_position->insert_after(min_constant);
489 }
490
491 // Load max Constant
492 Constant *max_constant = NULL;
493 if (info->_max != 0) {
494 max_constant = new Constant(new IntConstant(info->_max));
495 NOT_PRODUCT(max_constant->set_printable_bci(first->printable_bci()));
496 insert_position = insert_position->insert_after(max_constant);
497 }
498
499 // Load array length
500 Value length_instr = first->length();
501 if (!length_instr) {
502 ArrayLength *length = new ArrayLength(array, first->state_before()->copy());
503 length->set_exception_state(length->state_before());
504 length->set_flag(Instruction::DeoptimizeOnException, true);
505 insert_position = insert_position->insert_after_same_bci(length);
506 length_instr = length;
507 }
508
509 // Calculate lower bound
510 Instruction *lower_compare = index_instruction;
511 if (min_constant) {
512 ArithmeticOp *ao = new ArithmeticOp(Bytecodes::_iadd, min_constant, lower_compare, false, NULL);
513 insert_position = insert_position->insert_after_same_bci(ao);
514 lower_compare = ao;
515 }
516
517 // Calculate upper bound
518 Instruction *upper_compare = index_instruction;
519 if (max_constant) {
520 ArithmeticOp *ao = new ArithmeticOp(Bytecodes::_iadd, max_constant, upper_compare, false, NULL);
521 insert_position = insert_position->insert_after_same_bci(ao);
522 upper_compare = ao;
523 }
524
525 // Trick with unsigned compare is done
526 int bci = NOT_PRODUCT(first->printable_bci()) PRODUCT_ONLY(-1);
527 insert_position = predicate(upper_compare, Instruction::aeq, length_instr, state, insert_position, bci);
528 insert_position = predicate_cmp_with_const(lower_compare, Instruction::leq, -1, state, insert_position);
529 for (int j = 0; j<info->_list->length(); j++) {
530 AccessIndexed *ai = info->_list->at(j);
531 remove_range_check(ai);
532 }
533 }
534 _access_indexed_info[index_instruction->id()] = NULL;
535 }
536 indices.clear();
537
538 if (list_constant.length() > 1) {
539 AccessIndexed *first = list_constant.at(0);
540 Instruction *insert_position = first->prev();
541 ValueStack *state = first->state_before();
542 // Load max Constant
543 Constant *constant = new Constant(new IntConstant(max_constant));
544 NOT_PRODUCT(constant->set_printable_bci(first->printable_bci()));
545 insert_position = insert_position->insert_after(constant);
546 Instruction *compare_instr = constant;
547 Value length_instr = first->length();
548 if (!length_instr) {
549 ArrayLength *length = new ArrayLength(array, state->copy());
550 length->set_exception_state(length->state_before());
551 length->set_flag(Instruction::DeoptimizeOnException, true);
552 insert_position = insert_position->insert_after_same_bci(length);
553 length_instr = length;
554 }
555 // Compare for greater or equal to array length
556 insert_position = predicate(compare_instr, Instruction::geq, length_instr, state, insert_position);
557 for (int j = 0; j<list_constant.length(); j++) {
558 AccessIndexed *ai = list_constant.at(j);
559 remove_range_check(ai);
560 }
561 }
562 }
563 }
564 }
565
566 bool RangeCheckEliminator::set_process_block_flags(BlockBegin *block) {
567 Instruction *cur = block;
568 bool process = false;
569
570 while (cur) {
571 process |= (cur->as_AccessIndexed() != NULL);
572 cur = cur->next();
573 }
574
575 BlockList *dominates = block->dominates();
576 for (int i=0; i<dominates->length(); i++) {
577 BlockBegin *next = dominates->at(i);
578 process |= set_process_block_flags(next);
579 }
580
581 if (!process) {
582 block->set(BlockBegin::donot_eliminate_range_checks);
583 }
584 return process;
585 }
586
587 bool RangeCheckEliminator::is_ok_for_deoptimization(Instruction *insert_position, Instruction *array_instr, Instruction *length_instr, Instruction *lower_instr, int lower, Instruction *upper_instr, int upper) {
588 bool upper_check = true;
589 assert(lower_instr || lower >= 0, "If no lower_instr present, lower must be greater 0");
590 assert(!lower_instr || lower_instr->dominator_depth() <= insert_position->dominator_depth(), "Dominator depth must be smaller");
591 assert(!upper_instr || upper_instr->dominator_depth() <= insert_position->dominator_depth(), "Dominator depth must be smaller");
592 assert(array_instr, "Array instruction must exist");
593 assert(array_instr->dominator_depth() <= insert_position->dominator_depth(), "Dominator depth must be smaller");
594 assert(!length_instr || length_instr->dominator_depth() <= insert_position->dominator_depth(), "Dominator depth must be smaller");
595
596 if (upper_instr && upper_instr->as_ArrayLength() && upper_instr->as_ArrayLength()->array() == array_instr) {
597 // static check
598 if (upper >= 0) return false; // would always trigger a deopt:
599 // array_length + x >= array_length, x >= 0 is always true
600 upper_check = false;
601 }
602 if (lower_instr && lower_instr->as_ArrayLength() && lower_instr->as_ArrayLength()->array() == array_instr) {
603 if (lower > 0) return false;
604 }
605 // No upper check required -> skip
606 if (upper_check && upper_instr && upper_instr->type()->as_ObjectType() && upper_instr == array_instr) {
607 // upper_instr is object means that the upper bound is the length
608 // of the upper_instr.
609 return false;
610 }
611 return true;
612 }
613
614 Instruction* RangeCheckEliminator::insert_after(Instruction* insert_position, Instruction* instr, int bci) {
615 if (bci != -1) {
616 NOT_PRODUCT(instr->set_printable_bci(bci));
617 return insert_position->insert_after(instr);
618 } else {
619 return insert_position->insert_after_same_bci(instr);
620 }
621 }
622
623 Instruction* RangeCheckEliminator::predicate(Instruction* left, Instruction::Condition cond, Instruction* right, ValueStack* state, Instruction *insert_position, int bci) {
624 RangeCheckPredicate *deoptimize = new RangeCheckPredicate(left, cond, true, right, state->copy());
625 return insert_after(insert_position, deoptimize, bci);
626 }
627
628 Instruction* RangeCheckEliminator::predicate_cmp_with_const(Instruction* instr, Instruction::Condition cond, int constant, ValueStack* state, Instruction *insert_position, int bci) {
629 Constant *const_instr = new Constant(new IntConstant(constant));
630 insert_position = insert_after(insert_position, const_instr, bci);
631 return predicate(instr, cond, const_instr, state, insert_position);
632 }
633
634 Instruction* RangeCheckEliminator::predicate_add(Instruction* left, int left_const, Instruction::Condition cond, Instruction* right, ValueStack* state, Instruction *insert_position, int bci) {
635 Constant *constant = new Constant(new IntConstant(left_const));
636 insert_position = insert_after(insert_position, constant, bci);
637 ArithmeticOp *ao = new ArithmeticOp(Bytecodes::_iadd, constant, left, false, NULL);
638 insert_position = insert_position->insert_after_same_bci(ao);
639 return predicate(ao, cond, right, state, insert_position);
640 }
641
642 Instruction* RangeCheckEliminator::predicate_add_cmp_with_const(Instruction* left, int left_const, Instruction::Condition cond, int constant, ValueStack* state, Instruction *insert_position, int bci) {
643 Constant *const_instr = new Constant(new IntConstant(constant));
644 insert_position = insert_after(insert_position, const_instr, bci);
645 return predicate_add(left, left_const, cond, const_instr, state, insert_position);
646 }
647
648 // Insert deoptimization, returns true if sucessful or false if range check should not be removed
649 void RangeCheckEliminator::insert_deoptimization(ValueStack *state, Instruction *insert_position, Instruction *array_instr, Instruction *length_instr, Instruction *lower_instr, int lower, Instruction *upper_instr, int upper, AccessIndexed *ai) {
650 assert(is_ok_for_deoptimization(insert_position, array_instr, length_instr, lower_instr, lower, upper_instr, upper), "should have been tested before");
651 bool upper_check = !(upper_instr && upper_instr->as_ArrayLength() && upper_instr->as_ArrayLength()->array() == array_instr);
652
653 int bci = NOT_PRODUCT(ai->printable_bci()) PRODUCT_ONLY(-1);
654 if (lower_instr) {
655 assert(!lower_instr->type()->as_ObjectType(), "Must not be object type");
656 if (lower == 0) {
657 // Compare for less than 0
658 insert_position = predicate_cmp_with_const(lower_instr, Instruction::lss, 0, state, insert_position, bci);
659 } else if (lower > 0) {
660 // Compare for smaller 0
661 insert_position = predicate_add_cmp_with_const(lower_instr, lower, Instruction::lss, 0, state, insert_position, bci);
662 } else {
663 assert(lower < 0, "");
664 // Add 1
665 lower++;
666 lower = -lower;
667 // Compare for smaller or equal 0
668 insert_position = predicate_cmp_with_const(lower_instr, Instruction::leq, lower, state, insert_position, bci);
669 }
670 }
671
672 // We need to know length of array
673 if (!length_instr) {
674 // Load length if necessary
675 ArrayLength *length = new ArrayLength(array_instr, state->copy());
676 NOT_PRODUCT(length->set_printable_bci(ai->printable_bci()));
677 length->set_exception_state(length->state_before());
678 length->set_flag(Instruction::DeoptimizeOnException, true);
679 insert_position = insert_position->insert_after(length);
680 length_instr = length;
681 }
682
683 // No upper check required -> skip
684 if (!upper_check) return;
685
686 if (!upper_instr) {
687 // Compare for geq array.length
688 insert_position = predicate_cmp_with_const(length_instr, Instruction::leq, upper, state, insert_position, bci);
689 } else {
690 if (upper_instr->type()->as_ObjectType()) {
691 assert(state, "must not be null");
692 assert(upper_instr != array_instr, "should be");
693 ArrayLength *length = new ArrayLength(upper_instr, state->copy());
694 NOT_PRODUCT(length->set_printable_bci(ai->printable_bci()));
695 length->set_flag(Instruction::DeoptimizeOnException, true);
696 length->set_exception_state(length->state_before());
697 insert_position = insert_position->insert_after(length);
698 upper_instr = length;
699 }
700 assert(upper_instr->type()->as_IntType(), "Must not be object type!");
701
702 if (upper == 0) {
703 // Compare for geq array.length
704 insert_position = predicate(upper_instr, Instruction::geq, length_instr, state, insert_position, bci);
705 } else if (upper < 0) {
706 // Compare for geq array.length
707 insert_position = predicate_add(upper_instr, upper, Instruction::geq, length_instr, state, insert_position, bci);
708 } else {
709 assert(upper > 0, "");
710 upper = -upper;
711 // Compare for geq array.length
712 insert_position = predicate_add(length_instr, upper, Instruction::leq, upper_instr, state, insert_position, bci);
713 }
714 }
715 }
716
717 // Add if condition
718 void RangeCheckEliminator::add_if_condition(IntegerStack &pushed, Value x, Value y, Instruction::Condition condition) {
719 if (y->as_Constant()) return;
720
721 int const_value = 0;
722 Value instr_value = x;
723 Constant *c = x->as_Constant();
724 ArithmeticOp *ao = x->as_ArithmeticOp();
725
726 if (c != NULL) {
727 const_value = c->type()->as_IntConstant()->value();
728 instr_value = NULL;
729 } else if (ao != NULL && (!ao->x()->as_Constant() || !ao->y()->as_Constant()) && ((ao->op() == Bytecodes::_isub && ao->y()->as_Constant()) || ao->op() == Bytecodes::_iadd)) {
730 assert(!ao->x()->as_Constant() || !ao->y()->as_Constant(), "At least one operator must be non-constant!");
731 assert(ao->op() == Bytecodes::_isub || ao->op() == Bytecodes::_iadd, "Operation has to be add or sub!");
732 c = ao->x()->as_Constant();
733 if (c != NULL) {
734 const_value = c->type()->as_IntConstant()->value();
735 instr_value = ao->y();
736 } else {
737 c = ao->y()->as_Constant();
738 if (c != NULL) {
739 const_value = c->type()->as_IntConstant()->value();
740 instr_value = ao->x();
741 }
742 }
743 if (ao->op() == Bytecodes::_isub) {
744 assert(ao->y()->as_Constant(), "1 - x not supported, only x - 1 is valid!");
745 if (const_value > min_jint) {
746 const_value = -const_value;
747 } else {
748 const_value = 0;
749 instr_value = x;
750 }
751 }
752 }
753
754 update_bound(pushed, y, condition, instr_value, const_value);
755 }
756
757 // Process If
758 void RangeCheckEliminator::process_if(IntegerStack &pushed, BlockBegin *block, If *cond) {
759 // Only if we are direct true / false successor and NOT both ! (even this may occur)
760 if ((cond->tsux() == block || cond->fsux() == block) && cond->tsux() != cond->fsux()) {
761 Instruction::Condition condition = cond->cond();
762 if (cond->fsux() == block) {
763 condition = Instruction::negate(condition);
764 }
765 Value x = cond->x();
766 Value y = cond->y();
767 if (x->type()->as_IntType() && y->type()->as_IntType()) {
768 add_if_condition(pushed, y, x, condition);
769 add_if_condition(pushed, x, y, Instruction::mirror(condition));
770 }
771 }
772 }
773
774 // Process access indexed
775 void RangeCheckEliminator::process_access_indexed(BlockBegin *loop_header, BlockBegin *block, AccessIndexed *ai) {
776 TRACE_RANGE_CHECK_ELIMINATION(
777 tty->fill_to(block->dominator_depth()*2)
778 );
779 TRACE_RANGE_CHECK_ELIMINATION(
780 tty->print_cr("Access indexed: index=%d length=%d", ai->index()->id(), ai->length()->id())
781 );
782
783 if (ai->check_flag(Instruction::NeedsRangeCheckFlag)) {
784 Bound *index_bound = get_bound(ai->index());
785 if (!index_bound->has_lower() || !index_bound->has_upper()) {
786 TRACE_RANGE_CHECK_ELIMINATION(
787 tty->fill_to(block->dominator_depth()*2);
788 tty->print_cr("Index instruction %d has no lower and/or no upper bound!", ai->index()->id())
789 );
790 return;
791 }
792
793 Bound *array_bound;
794 if (ai->length()) {
795 array_bound = get_bound(ai->length());
796 } else {
797 array_bound = get_bound(ai->array());
798 }
799
800 if (in_array_bound(index_bound, ai->array()) ||
801 (index_bound && array_bound && index_bound->is_smaller(array_bound) && !index_bound->lower_instr() && index_bound->lower() >= 0)) {
802 TRACE_RANGE_CHECK_ELIMINATION(
803 tty->fill_to(block->dominator_depth()*2);
804 tty->print_cr("Bounds check for instruction %d in block B%d can be fully eliminated!", ai->id(), ai->block()->block_id())
805 );
806
807 remove_range_check(ai);
808 } else if (_optimistic && loop_header) {
809 assert(ai->array(), "Array must not be null!");
810 assert(ai->index(), "Index must not be null!");
811
812 // Array instruction
813 Instruction *array_instr = ai->array();
814 if (!loop_invariant(loop_header, array_instr)) {
815 TRACE_RANGE_CHECK_ELIMINATION(
816 tty->fill_to(block->dominator_depth()*2);
817 tty->print_cr("Array %d is not loop invariant to header B%d", ai->array()->id(), loop_header->block_id())
818 );
819 return;
820 }
821
822 // Lower instruction
823 Value index_instr = ai->index();
824 Value lower_instr = index_bound->lower_instr();
825 if (!loop_invariant(loop_header, lower_instr)) {
826 TRACE_RANGE_CHECK_ELIMINATION(
827 tty->fill_to(block->dominator_depth()*2);
828 tty->print_cr("Lower instruction %d not loop invariant!", lower_instr->id())
829 );
830 return;
831 }
832 if (!lower_instr && index_bound->lower() < 0) {
833 TRACE_RANGE_CHECK_ELIMINATION(
834 tty->fill_to(block->dominator_depth()*2);
835 tty->print_cr("Lower bound smaller than 0 (%d)!", index_bound->lower())
836 );
837 return;
838 }
839
840 // Upper instruction
841 Value upper_instr = index_bound->upper_instr();
842 if (!loop_invariant(loop_header, upper_instr)) {
843 TRACE_RANGE_CHECK_ELIMINATION(
844 tty->fill_to(block->dominator_depth()*2);
845 tty->print_cr("Upper instruction %d not loop invariant!", upper_instr->id())
846 );
847 return;
848 }
849
850 // Length instruction
851 Value length_instr = ai->length();
852 if (!loop_invariant(loop_header, length_instr)) {
853 // Generate length instruction yourself!
854 length_instr = NULL;
855 }
856
857 TRACE_RANGE_CHECK_ELIMINATION(
858 tty->fill_to(block->dominator_depth()*2);
859 tty->print_cr("LOOP INVARIANT access indexed %d found in block B%d!", ai->id(), ai->block()->block_id())
860 );
861
862 BlockBegin *pred_block = loop_header->dominator();
863 assert(pred_block != NULL, "Every loop header has a dominator!");
864 BlockEnd *pred_block_end = pred_block->end();
865 Instruction *insert_position = pred_block_end->prev();
866 ValueStack *state = pred_block_end->state_before();
867 if (pred_block_end->as_Goto() && state == NULL) state = pred_block_end->state();
868 assert(state, "State must not be null");
869
870 // Add deoptimization to dominator of loop header
871 TRACE_RANGE_CHECK_ELIMINATION(
872 tty->fill_to(block->dominator_depth()*2);
873 tty->print_cr("Inserting deopt at bci %d in block B%d!", state->bci(), insert_position->block()->block_id())
874 );
875
876 if (!is_ok_for_deoptimization(insert_position, array_instr, length_instr, lower_instr, index_bound->lower(), upper_instr, index_bound->upper())) {
877 TRACE_RANGE_CHECK_ELIMINATION(
878 tty->fill_to(block->dominator_depth()*2);
879 tty->print_cr("Could not eliminate because of static analysis!")
880 );
881 return;
882 }
883
884 insert_deoptimization(state, insert_position, array_instr, length_instr, lower_instr, index_bound->lower(), upper_instr, index_bound->upper(), ai);
885
886 // Finally remove the range check!
887 remove_range_check(ai);
888 }
889 }
890 }
891
892 void RangeCheckEliminator::remove_range_check(AccessIndexed *ai) {
893 ai->set_flag(Instruction::NeedsRangeCheckFlag, false);
894 // no range check, no need for the length instruction anymore
895 ai->clear_length();
896
897 TRACE_RANGE_CHECK_ELIMINATION(
898 tty->fill_to(ai->dominator_depth()*2);
899 tty->print_cr("Range check for instruction %d eliminated!", ai->id());
900 );
901
902 ASSERT_RANGE_CHECK_ELIMINATION(
903 Value array_length = ai->length();
904 if (!array_length) {
905 array_length = ai->array();
906 assert(array_length->type()->as_ObjectType(), "Has to be object type!");
907 }
908 int cur_constant = -1;
909 Value cur_value = array_length;
910 if (cur_value->type()->as_IntConstant()) {
911 cur_constant += cur_value->type()->as_IntConstant()->value();
912 cur_value = NULL;
913 }
914 Bound *new_index_bound = new Bound(0, NULL, cur_constant, cur_value);
915 add_assertions(new_index_bound, ai->index(), ai);
916 );
917 }
918
919 // Calculate bounds for instruction in this block and children blocks in the dominator tree
920 void RangeCheckEliminator::calc_bounds(BlockBegin *block, BlockBegin *loop_header) {
921 // Ensures a valid loop_header
922 assert(!loop_header || loop_header->is_set(BlockBegin::linear_scan_loop_header_flag), "Loop header has to be real !");
923
924 // Tracing output
925 TRACE_RANGE_CHECK_ELIMINATION(
926 tty->fill_to(block->dominator_depth()*2);
927 tty->print_cr("Block B%d", block->block_id());
928 );
929
930 // Pushed stack for conditions
931 IntegerStack pushed;
932 // Process If
933 BlockBegin *parent = block->dominator();
934 if (parent != NULL) {
935 If *cond = parent->end()->as_If();
936 if (cond != NULL) {
937 process_if(pushed, block, cond);
938 }
939 }
940
941 // Interate over current block
942 InstructionList arrays;
943 AccessIndexedList accessIndexed;
944 Instruction *cur = block;
945
946 while (cur) {
947 // Ensure cur wasn't inserted during the elimination
948 if (cur->id() < this->_bounds.length()) {
949 // Process only if it is an access indexed instruction
950 AccessIndexed *ai = cur->as_AccessIndexed();
951 if (ai != NULL) {
952 process_access_indexed(loop_header, block, ai);
953 accessIndexed.append(ai);
954 if (!arrays.contains(ai->array())) {
955 arrays.append(ai->array());
956 }
957 Bound *b = get_bound(ai->index());
958 if (!b->lower_instr()) {
959 // Lower bound is constant
960 update_bound(pushed, ai->index(), Instruction::geq, NULL, 0);
961 }
962 if (!b->has_upper()) {
963 if (ai->length() && ai->length()->type()->as_IntConstant()) {
964 int value = ai->length()->type()->as_IntConstant()->value();
965 update_bound(pushed, ai->index(), Instruction::lss, NULL, value);
966 } else {
967 // Has no upper bound
968 Instruction *instr = ai->length();
969 if (instr != NULL) instr = ai->array();
970 update_bound(pushed, ai->index(), Instruction::lss, instr, 0);
971 }
972 }
973 }
974 }
975 cur = cur->next();
976 }
977
978 // Output current condition stack
979 TRACE_RANGE_CHECK_ELIMINATION(dump_condition_stack(block));
980
981 // Do in block motion of range checks
982 in_block_motion(block, accessIndexed, arrays);
983
984 // Call all dominated blocks
985 for (int i=0; i<block->dominates()->length(); i++) {
986 BlockBegin *next = block->dominates()->at(i);
987 if (!next->is_set(BlockBegin::donot_eliminate_range_checks)) {
988 // if current block is a loop header and:
989 // - next block belongs to the same loop
990 // or
991 // - next block belongs to an inner loop
992 // then current block is the loop header for next block
993 if (block->is_set(BlockBegin::linear_scan_loop_header_flag) && (block->loop_index() == next->loop_index() || next->loop_depth() > block->loop_depth())) {
994 calc_bounds(next, block);
995 } else {
996 calc_bounds(next, loop_header);
997 }
998 }
999 }
1000
1001 // Reset stack
1002 for (int i=0; i<pushed.length(); i++) {
1003 _bounds[pushed[i]]->pop();
1004 }
1005 }
1006
1007 #ifndef PRODUCT
1008 // Dump condition stack
1009 void RangeCheckEliminator::dump_condition_stack(BlockBegin *block) {
1010 for (int i=0; i<_ir->linear_scan_order()->length(); i++) {
1011 BlockBegin *cur_block = _ir->linear_scan_order()->at(i);
1012 Instruction *instr = cur_block;
1013 for_each_phi_fun(cur_block, phi,
1014 BoundStack *bound_stack = _bounds.at(phi->id());
1015 if (bound_stack && bound_stack->length() > 0) {
1016 Bound *bound = bound_stack->top();
1017 if ((bound->has_lower() || bound->has_upper()) && (bound->lower_instr() != phi || bound->upper_instr() != phi || bound->lower() != 0 || bound->upper() != 0)) {
1018 TRACE_RANGE_CHECK_ELIMINATION(tty->fill_to(2*block->dominator_depth());
1019 tty->print("i%d", phi->id());
1020 tty->print(": ");
1021 bound->print();
1022 tty->print_cr("");
1023 );
1024 }
1025 });
1026
1027 while (!instr->as_BlockEnd()) {
1028 if (instr->id() < _bounds.length()) {
1029 BoundStack *bound_stack = _bounds.at(instr->id());
1030 if (bound_stack && bound_stack->length() > 0) {
1031 Bound *bound = bound_stack->top();
1032 if ((bound->has_lower() || bound->has_upper()) && (bound->lower_instr() != instr || bound->upper_instr() != instr || bound->lower() != 0 || bound->upper() != 0)) {
1033 TRACE_RANGE_CHECK_ELIMINATION(tty->fill_to(2*block->dominator_depth());
1034 tty->print("i%d", instr->id());
1035 tty->print(": ");
1036 bound->print();
1037 tty->print_cr("");
1038 );
1039 }
1040 }
1041 }
1042 instr = instr->next();
1043 }
1044 }
1045 }
1046 #endif
1047
1048 // Verification or the IR
1049 RangeCheckEliminator::Verification::Verification(IR *ir) : _used(BlockBegin::number_of_blocks(), false) {
1050 this->_ir = ir;
1051 ir->iterate_linear_scan_order(this);
1052 }
1053
1054 // Verify this block
1055 void RangeCheckEliminator::Verification::block_do(BlockBegin *block) {
1056 If *cond = block->end()->as_If();
1057 // Watch out: tsux and fsux can be the same!
1058 if (block->number_of_sux() > 1) {
1059 for (int i=0; i<block->number_of_sux(); i++) {
1060 BlockBegin *sux = block->sux_at(i);
1061 BlockBegin *pred = NULL;
1062 for (int j=0; j<sux->number_of_preds(); j++) {
1063 BlockBegin *cur = sux->pred_at(j);
1064 assert(cur != NULL, "Predecessor must not be null");
1065 if (!pred) {
1066 pred = cur;
1067 }
1068 assert(cur == pred, "Block must not have more than one predecessor if its predecessor has more than one successor");
1069 }
1070 assert(sux->number_of_preds() >= 1, "Block must have at least one predecessor");
1071 assert(sux->pred_at(0) == block, "Wrong successor");
1072 }
1073 }
1074
1075 BlockBegin *dominator = block->dominator();
1076 if (dominator) {
1077 assert(block != _ir->start(), "Start block must not have a dominator!");
1078 assert(can_reach(dominator, block), "Dominator can't reach his block !");
1079 assert(can_reach(_ir->start(), dominator), "Dominator is unreachable !");
1080 assert(!can_reach(_ir->start(), block, dominator), "Wrong dominator ! Block can be reached anyway !");
1081 BlockList *all_blocks = _ir->linear_scan_order();
1082 for (int i=0; i<all_blocks->length(); i++) {
1083 BlockBegin *cur = all_blocks->at(i);
1084 if (cur != dominator && cur != block) {
1085 assert(can_reach(dominator, block, cur), "There has to be another dominator!");
1086 }
1087 }
1088 } else {
1089 assert(block == _ir->start(), "Only start block must not have a dominator");
1090 }
1091
1092 if (block->is_set(BlockBegin::linear_scan_loop_header_flag)) {
1093 int loop_index = block->loop_index();
1094 BlockList *all_blocks = _ir->linear_scan_order();
1095 assert(block->number_of_preds() >= 1, "Block must have at least one predecessor");
1096 assert(!block->is_set(BlockBegin::exception_entry_flag), "Loop header must not be exception handler!");
1097 // Sometimes, the backbranch comes from an exception handler. In
1098 // this case, loop indexes/loop depths may not appear correct.
1099 bool loop_through_xhandler = false;
1100 for (int i = 0; i < block->number_of_exception_handlers(); i++) {
1101 BlockBegin *xhandler = block->exception_handler_at(i);
1102 for (int j = 0; j < block->number_of_preds(); j++) {
1103 if (dominates(xhandler, block->pred_at(j)) || xhandler == block->pred_at(j)) {
1104 loop_through_xhandler = true;
1105 }
1106 }
1107 }
1108
1109 for (int i=0; i<block->number_of_sux(); i++) {
1110 BlockBegin *sux = block->sux_at(i);
1111 assert(sux->loop_depth() != block->loop_depth() || sux->loop_index() == block->loop_index() || loop_through_xhandler, "Loop index has to be same");
1112 assert(sux->loop_depth() == block->loop_depth() || sux->loop_index() != block->loop_index(), "Loop index has to be different");
1113 }
1114
1115 for (int i=0; i<all_blocks->length(); i++) {
1116 BlockBegin *cur = all_blocks->at(i);
1117 if (cur->loop_index() == loop_index && cur != block) {
1118 assert(dominates(block->dominator(), cur), "Dominator of loop header must dominate all loop blocks");
1119 }
1120 }
1121 }
1122
1123 Instruction *cur = block;
1124 while (cur) {
1125 assert(cur->block() == block, "Block begin has to be set correctly!");
1126 cur = cur->next();
1127 }
1128 }
1129
1130 // Loop header must dominate all loop blocks
1131 bool RangeCheckEliminator::Verification::dominates(BlockBegin *dominator, BlockBegin *block) {
1132 BlockBegin *cur = block->dominator();
1133 while (cur && cur != dominator) {
1134 cur = cur->dominator();
1135 }
1136 return cur == dominator;
1137 }
1138
1139 // Try to reach Block end beginning in Block start and not using Block dont_use
1140 bool RangeCheckEliminator::Verification::can_reach(BlockBegin *start, BlockBegin *end, BlockBegin *dont_use /* = NULL */) {
1141 if (start == end) return start != dont_use;
1142 // Simple BSF from start to end
1143 // BlockBeginList _current;
1144 for (int i=0; i<_used.length(); i++) {
1145 _used[i] = false;
1146 }
1147 _current.truncate(0);
1148 _successors.truncate(0);
1149 if (start != dont_use) {
1150 _current.push(start);
1151 _used[start->block_id()] = true;
1152 }
1153
1154 // BlockBeginList _successors;
1155 while (_current.length() > 0) {
1156 BlockBegin *cur = _current.pop();
1157 // Add exception handlers to list
1158 for (int i=0; i<cur->number_of_exception_handlers(); i++) {
1159 BlockBegin *xhandler = cur->exception_handler_at(i);
1160 _successors.push(xhandler);
1161 // Add exception handlers of _successors to list
1162 for (int j=0; j<xhandler->number_of_exception_handlers(); j++) {
1163 BlockBegin *sux_xhandler = xhandler->exception_handler_at(j);
1164 _successors.push(sux_xhandler);
1165 }
1166 }
1167 // Add normal _successors to list
1168 for (int i=0; i<cur->number_of_sux(); i++) {
1169 BlockBegin *sux = cur->sux_at(i);
1170 _successors.push(sux);
1171 // Add exception handlers of _successors to list
1172 for (int j=0; j<sux->number_of_exception_handlers(); j++) {
1173 BlockBegin *xhandler = sux->exception_handler_at(j);
1174 _successors.push(xhandler);
1175 }
1176 }
1177 for (int i=0; i<_successors.length(); i++) {
1178 BlockBegin *sux = _successors[i];
1179 assert(sux != NULL, "Successor must not be NULL!");
1180 if (sux == end) {
1181 return true;
1182 }
1183 if (sux != dont_use && !_used[sux->block_id()]) {
1184 _used[sux->block_id()] = true;
1185 _current.push(sux);
1186 }
1187 }
1188 _successors.truncate(0);
1189 }
1190
1191 return false;
1192 }
1193
1194 // Bound
1195 RangeCheckEliminator::Bound::~Bound() {
1196 }
1197
1198 // Bound constructor
1199 RangeCheckEliminator::Bound::Bound() {
1200 init();
1201 this->_lower = min_jint;
1202 this->_upper = max_jint;
1203 this->_lower_instr = NULL;
1204 this->_upper_instr = NULL;
1205 }
1206
1207 // Bound constructor
1208 RangeCheckEliminator::Bound::Bound(int lower, Value lower_instr, int upper, Value upper_instr) {
1209 init();
1210 assert(!lower_instr || !lower_instr->as_Constant() || !lower_instr->type()->as_IntConstant(), "Must not be constant!");
1211 assert(!upper_instr || !upper_instr->as_Constant() || !upper_instr->type()->as_IntConstant(), "Must not be constant!");
1212 this->_lower = lower;
1213 this->_upper = upper;
1214 this->_lower_instr = lower_instr;
1215 this->_upper_instr = upper_instr;
1216 }
1217
1218 // Bound constructor
1219 RangeCheckEliminator::Bound::Bound(Instruction::Condition cond, Value v, int constant) {
1220 assert(!v || (v->type() && (v->type()->as_IntType() || v->type()->as_ObjectType())), "Type must be array or integer!");
1221 assert(!v || !v->as_Constant() || !v->type()->as_IntConstant(), "Must not be constant!");
1222
1223 init();
1224 if (cond == Instruction::eql) {
1225 _lower = constant;
1226 _lower_instr = v;
1227 _upper = constant;
1228 _upper_instr = v;
1229 } else if (cond == Instruction::neq) {
1230 _lower = min_jint;
1231 _upper = max_jint;
1232 _lower_instr = NULL;
1233 _upper_instr = NULL;
1234 if (v == NULL) {
1235 if (constant == min_jint) {
1236 _lower++;
1237 }
1238 if (constant == max_jint) {
1239 _upper--;
1240 }
1241 }
1242 } else if (cond == Instruction::geq) {
1243 _lower = constant;
1244 _lower_instr = v;
1245 _upper = max_jint;
1246 _upper_instr = NULL;
1247 } else if (cond == Instruction::leq) {
1248 _lower = min_jint;
1249 _lower_instr = NULL;
1250 _upper = constant;
1251 _upper_instr = v;
1252 } else {
1253 ShouldNotReachHere();
1254 }
1255 }
1256
1257 // Set lower
1258 void RangeCheckEliminator::Bound::set_lower(int value, Value v) {
1259 assert(!v || !v->as_Constant() || !v->type()->as_IntConstant(), "Must not be constant!");
1260 this->_lower = value;
1261 this->_lower_instr = v;
1262 }
1263
1264 // Set upper
1265 void RangeCheckEliminator::Bound::set_upper(int value, Value v) {
1266 assert(!v || !v->as_Constant() || !v->type()->as_IntConstant(), "Must not be constant!");
1267 this->_upper = value;
1268 this->_upper_instr = v;
1269 }
1270
1271 // Add constant -> no overflow may occur
1272 void RangeCheckEliminator::Bound::add_constant(int value) {
1273 this->_lower += value;
1274 this->_upper += value;
1275 }
1276
1277 // Init
1278 void RangeCheckEliminator::Bound::init() {
1279 }
1280
1281 // or
1282 void RangeCheckEliminator::Bound::or_op(Bound *b) {
1283 // Watch out, bound is not guaranteed not to overflow!
1284 // Update lower bound
1285 if (_lower_instr != b->_lower_instr || (_lower_instr && _lower != b->_lower)) {
1286 _lower_instr = NULL;
1287 _lower = min_jint;
1288 } else {
1289 _lower = MIN2(_lower, b->_lower);
1290 }
1291 // Update upper bound
1292 if (_upper_instr != b->_upper_instr || (_upper_instr && _upper != b->_upper)) {
1293 _upper_instr = NULL;
1294 _upper = max_jint;
1295 } else {
1296 _upper = MAX2(_upper, b->_upper);
1297 }
1298 }
1299
1300 // and
1301 void RangeCheckEliminator::Bound::and_op(Bound *b) {
1302 // Update lower bound
1303 if (_lower_instr == b->_lower_instr) {
1304 _lower = MAX2(_lower, b->_lower);
1305 }
1306 if (b->has_lower()) {
1307 bool set = true;
1308 if (_lower_instr != NULL && b->_lower_instr != NULL) {
1309 set = (_lower_instr->dominator_depth() > b->_lower_instr->dominator_depth());
1310 }
1311 if (set) {
1312 _lower = b->_lower;
1313 _lower_instr = b->_lower_instr;
1314 }
1315 }
1316 // Update upper bound
1317 if (_upper_instr == b->_upper_instr) {
1318 _upper = MIN2(_upper, b->_upper);
1319 }
1320 if (b->has_upper()) {
1321 bool set = true;
1322 if (_upper_instr != NULL && b->_upper_instr != NULL) {
1323 set = (_upper_instr->dominator_depth() > b->_upper_instr->dominator_depth());
1324 }
1325 if (set) {
1326 _upper = b->_upper;
1327 _upper_instr = b->_upper_instr;
1328 }
1329 }
1330 }
1331
1332 // has_upper
1333 bool RangeCheckEliminator::Bound::has_upper() {
1334 return _upper_instr != NULL || _upper < max_jint;
1335 }
1336
1337 // is_smaller
1338 bool RangeCheckEliminator::Bound::is_smaller(Bound *b) {
1339 if (b->_lower_instr != _upper_instr) {
1340 return false;
1341 }
1342 return _upper < b->_lower;
1343 }
1344
1345 // has_lower
1346 bool RangeCheckEliminator::Bound::has_lower() {
1347 return _lower_instr != NULL || _lower > min_jint;
1348 }
1349
1350 // in_array_bound
1351 bool RangeCheckEliminator::in_array_bound(Bound *bound, Value array){
1352 if (!bound) return false;
1353 assert(array != NULL, "Must not be null!");
1354 assert(bound != NULL, "Must not be null!");
1355 if (bound->lower() >=0 && bound->lower_instr() == NULL && bound->upper() < 0 && bound->upper_instr() != NULL) {
1356 ArrayLength *len = bound->upper_instr()->as_ArrayLength();
1357 if (bound->upper_instr() == array || (len != NULL && len->array() == array)) {
1358 return true;
1359 }
1360 }
1361 return false;
1362 }
1363
1364 // remove_lower
1365 void RangeCheckEliminator::Bound::remove_lower() {
1366 _lower = min_jint;
1367 _lower_instr = NULL;
1368 }
1369
1370 // remove_upper
1371 void RangeCheckEliminator::Bound::remove_upper() {
1372 _upper = max_jint;
1373 _upper_instr = NULL;
1374 }
1375
1376 // upper
1377 int RangeCheckEliminator::Bound::upper() {
1378 return _upper;
1379 }
1380
1381 // lower
1382 int RangeCheckEliminator::Bound::lower() {
1383 return _lower;
1384 }
1385
1386 // upper_instr
1387 Value RangeCheckEliminator::Bound::upper_instr() {
1388 return _upper_instr;
1389 }
1390
1391 // lower_instr
1392 Value RangeCheckEliminator::Bound::lower_instr() {
1393 return _lower_instr;
1394 }
1395
1396 // print
1397 void RangeCheckEliminator::Bound::print() {
1398 tty->print("");
1399 if (this->_lower_instr || this->_lower != min_jint) {
1400 if (this->_lower_instr) {
1401 tty->print("i%d", this->_lower_instr->id());
1402 if (this->_lower > 0) {
1403 tty->print("+%d", _lower);
1404 }
1405 if (this->_lower < 0) {
1406 tty->print("%d", _lower);
1407 }
1408 } else {
1409 tty->print("%d", _lower);
1410 }
1411 tty->print(" <= ");
1412 }
1413 tty->print("x");
1414 if (this->_upper_instr || this->_upper != max_jint) {
1415 tty->print(" <= ");
1416 if (this->_upper_instr) {
1417 tty->print("i%d", this->_upper_instr->id());
1418 if (this->_upper > 0) {
1419 tty->print("+%d", _upper);
1420 }
1421 if (this->_upper < 0) {
1422 tty->print("%d", _upper);
1423 }
1424 } else {
1425 tty->print("%d", _upper);
1426 }
1427 }
1428 }
1429
1430 // Copy
1431 RangeCheckEliminator::Bound *RangeCheckEliminator::Bound::copy() {
1432 Bound *b = new Bound();
1433 b->_lower = _lower;
1434 b->_lower_instr = _lower_instr;
1435 b->_upper = _upper;
1436 b->_upper_instr = _upper_instr;
1437 return b;
1438 }
1439
1440 #ifdef ASSERT
1441 // Add assertion
1442 void RangeCheckEliminator::Bound::add_assertion(Instruction *instruction, Instruction *position, int i, Value instr, Instruction::Condition cond) {
1443 Instruction *result = position;
1444 Instruction *compare_with = NULL;
1445 ValueStack *state = position->state_before();
1446 if (position->as_BlockEnd() && !position->as_Goto()) {
1447 state = position->as_BlockEnd()->state_before();
1448 }
1449 Instruction *instruction_before = position->prev();
1450 if (position->as_Return() && Compilation::current()->method()->is_synchronized() && instruction_before->as_MonitorExit()) {
1451 instruction_before = instruction_before->prev();
1452 }
1453 result = instruction_before;
1454 // Load constant only if needed
1455 Constant *constant = NULL;
1456 if (i != 0 || !instr) {
1457 constant = new Constant(new IntConstant(i));
1458 NOT_PRODUCT(constant->set_printable_bci(position->printable_bci()));
1459 result = result->insert_after(constant);
1460 compare_with = constant;
1461 }
1462
1463 if (instr) {
1464 assert(instr->type()->as_ObjectType() || instr->type()->as_IntType(), "Type must be array or integer!");
1465 compare_with = instr;
1466 // Load array length if necessary
1467 Instruction *op = instr;
1468 if (instr->type()->as_ObjectType()) {
1469 assert(state, "must not be null");
1470 ArrayLength *length = new ArrayLength(instr, state->copy());
1471 NOT_PRODUCT(length->set_printable_bci(position->printable_bci()));
1472 length->set_exception_state(length->state_before());
1473 result = result->insert_after(length);
1474 op = length;
1475 compare_with = length;
1476 }
1477 // Add operation only if necessary
1478 if (constant) {
1479 ArithmeticOp *ao = new ArithmeticOp(Bytecodes::_iadd, constant, op, false, NULL);
1480 NOT_PRODUCT(ao->set_printable_bci(position->printable_bci()));
1481 result = result->insert_after(ao);
1482 compare_with = ao;
1483 // TODO: Check that add operation does not overflow!
1484 }
1485 }
1486 assert(compare_with != NULL, "You have to compare with something!");
1487 assert(instruction != NULL, "Instruction must not be null!");
1488
1489 if (instruction->type()->as_ObjectType()) {
1490 // Load array length if necessary
1491 Instruction *op = instruction;
1492 assert(state, "must not be null");
1493 ArrayLength *length = new ArrayLength(instruction, state->copy());
1494 length->set_exception_state(length->state_before());
1495 NOT_PRODUCT(length->set_printable_bci(position->printable_bci()));
1496 result = result->insert_after(length);
1497 instruction = length;
1498 }
1499
1500 Assert *assert = new Assert(instruction, cond, false, compare_with);
1501 NOT_PRODUCT(assert->set_printable_bci(position->printable_bci()));
1502 result->insert_after(assert);
1503 }
1504
1505 // Add assertions
1506 void RangeCheckEliminator::add_assertions(Bound *bound, Instruction *instruction, Instruction *position) {
1507 // Add lower bound assertion
1508 if (bound->has_lower()) {
1509 bound->add_assertion(instruction, position, bound->lower(), bound->lower_instr(), Instruction::geq);
1510 }
1511 // Add upper bound assertion
1512 if (bound->has_upper()) {
1513 bound->add_assertion(instruction, position, bound->upper(), bound->upper_instr(), Instruction::leq);
1514 }
1515 }
1516 #endif
1517

Mercurial Repository: jdk8-mips64-public/hotspot

mercurial