1 /*
2 * Copyright 2005-2009 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 #include "incls/_precompiled.incl"
26 #include "incls/_c1_LinearScan.cpp.incl"
27
28
29 #ifndef PRODUCT
30
31 static LinearScanStatistic _stat_before_alloc;
32 static LinearScanStatistic _stat_after_asign;
33 static LinearScanStatistic _stat_final;
34
35 static LinearScanTimers _total_timer;
36
37 // helper macro for short definition of timer
38 #define TIME_LINEAR_SCAN(timer_name) TraceTime _block_timer("", _total_timer.timer(LinearScanTimers::timer_name), TimeLinearScan || TimeEachLinearScan, Verbose);
39
40 // helper macro for short definition of trace-output inside code
41 #define TRACE_LINEAR_SCAN(level, code) \
42 if (TraceLinearScanLevel >= level) { \
43 code; \
44 }
45
46 #else
47
48 #define TIME_LINEAR_SCAN(timer_name)
49 #define TRACE_LINEAR_SCAN(level, code)
50
51 #endif
52
53 // Map BasicType to spill size in 32-bit words, matching VMReg's notion of words
54 #ifdef _LP64
55 static int type2spill_size[T_CONFLICT+1]={ -1, 0, 0, 0, 1, 1, 1, 2, 1, 1, 1, 2, 2, 2, 0, 1, -1};
56 #else
57 static int type2spill_size[T_CONFLICT+1]={ -1, 0, 0, 0, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 0, 1, -1};
58 #endif
59
60
61 // Implementation of LinearScan
62
63 LinearScan::LinearScan(IR* ir, LIRGenerator* gen, FrameMap* frame_map)
64 : _compilation(ir->compilation())
65 , _ir(ir)
66 , _gen(gen)
67 , _frame_map(frame_map)
68 , _num_virtual_regs(gen->max_virtual_register_number())
69 , _has_fpu_registers(false)
70 , _num_calls(-1)
71 , _max_spills(0)
72 , _unused_spill_slot(-1)
73 , _intervals(0) // initialized later with correct length
74 , _new_intervals_from_allocation(new IntervalList())
75 , _sorted_intervals(NULL)
76 , _lir_ops(0) // initialized later with correct length
77 , _block_of_op(0) // initialized later with correct length
78 , _has_info(0)
79 , _has_call(0)
80 , _scope_value_cache(0) // initialized later with correct length
81 , _interval_in_loop(0, 0) // initialized later with correct length
82 , _cached_blocks(*ir->linear_scan_order())
83 #ifdef X86
84 , _fpu_stack_allocator(NULL)
85 #endif
86 {
87 // note: to use more than on instance of LinearScan at a time this function call has to
88 // be moved somewhere outside of this constructor:
89 Interval::initialize();
90
91 assert(this->ir() != NULL, "check if valid");
92 assert(this->compilation() != NULL, "check if valid");
93 assert(this->gen() != NULL, "check if valid");
94 assert(this->frame_map() != NULL, "check if valid");
95 }
96
97
98 // ********** functions for converting LIR-Operands to register numbers
99 //
100 // Emulate a flat register file comprising physical integer registers,
101 // physical floating-point registers and virtual registers, in that order.
102 // Virtual registers already have appropriate numbers, since V0 is
103 // the number of physical registers.
104 // Returns -1 for hi word if opr is a single word operand.
105 //
106 // Note: the inverse operation (calculating an operand for register numbers)
107 // is done in calc_operand_for_interval()
108
109 int LinearScan::reg_num(LIR_Opr opr) {
110 assert(opr->is_register(), "should not call this otherwise");
111
112 if (opr->is_virtual_register()) {
113 assert(opr->vreg_number() >= nof_regs, "found a virtual register with a fixed-register number");
114 return opr->vreg_number();
115 } else if (opr->is_single_cpu()) {
116 return opr->cpu_regnr();
117 } else if (opr->is_double_cpu()) {
118 return opr->cpu_regnrLo();
119 #ifdef X86
120 } else if (opr->is_single_xmm()) {
121 return opr->fpu_regnr() + pd_first_xmm_reg;
122 } else if (opr->is_double_xmm()) {
123 return opr->fpu_regnrLo() + pd_first_xmm_reg;
124 #endif
125 } else if (opr->is_single_fpu()) {
126 return opr->fpu_regnr() + pd_first_fpu_reg;
127 } else if (opr->is_double_fpu()) {
128 return opr->fpu_regnrLo() + pd_first_fpu_reg;
129 } else {
130 ShouldNotReachHere();
131 return -1;
132 }
133 }
134
135 int LinearScan::reg_numHi(LIR_Opr opr) {
136 assert(opr->is_register(), "should not call this otherwise");
137
138 if (opr->is_virtual_register()) {
139 return -1;
140 } else if (opr->is_single_cpu()) {
141 return -1;
142 } else if (opr->is_double_cpu()) {
143 return opr->cpu_regnrHi();
144 #ifdef X86
145 } else if (opr->is_single_xmm()) {
146 return -1;
147 } else if (opr->is_double_xmm()) {
148 return -1;
149 #endif
150 } else if (opr->is_single_fpu()) {
151 return -1;
152 } else if (opr->is_double_fpu()) {
153 return opr->fpu_regnrHi() + pd_first_fpu_reg;
154 } else {
155 ShouldNotReachHere();
156 return -1;
157 }
158 }
159
160
161 // ********** functions for classification of intervals
162
163 bool LinearScan::is_precolored_interval(const Interval* i) {
164 return i->reg_num() < LinearScan::nof_regs;
165 }
166
167 bool LinearScan::is_virtual_interval(const Interval* i) {
168 return i->reg_num() >= LIR_OprDesc::vreg_base;
169 }
170
171 bool LinearScan::is_precolored_cpu_interval(const Interval* i) {
172 return i->reg_num() < LinearScan::nof_cpu_regs;
173 }
174
175 bool LinearScan::is_virtual_cpu_interval(const Interval* i) {
176 return i->reg_num() >= LIR_OprDesc::vreg_base && (i->type() != T_FLOAT && i->type() != T_DOUBLE);
177 }
178
179 bool LinearScan::is_precolored_fpu_interval(const Interval* i) {
180 return i->reg_num() >= LinearScan::nof_cpu_regs && i->reg_num() < LinearScan::nof_regs;
181 }
182
183 bool LinearScan::is_virtual_fpu_interval(const Interval* i) {
184 return i->reg_num() >= LIR_OprDesc::vreg_base && (i->type() == T_FLOAT || i->type() == T_DOUBLE);
185 }
186
187 bool LinearScan::is_in_fpu_register(const Interval* i) {
188 // fixed intervals not needed for FPU stack allocation
189 return i->reg_num() >= nof_regs && pd_first_fpu_reg <= i->assigned_reg() && i->assigned_reg() <= pd_last_fpu_reg;
190 }
191
192 bool LinearScan::is_oop_interval(const Interval* i) {
193 // fixed intervals never contain oops
194 return i->reg_num() >= nof_regs && i->type() == T_OBJECT;
195 }
196
197
198 // ********** General helper functions
199
200 // compute next unused stack index that can be used for spilling
201 int LinearScan::allocate_spill_slot(bool double_word) {
202 int spill_slot;
203 if (double_word) {
204 if ((_max_spills & 1) == 1) {
205 // alignment of double-word values
206 // the hole because of the alignment is filled with the next single-word value
207 assert(_unused_spill_slot == -1, "wasting a spill slot");
208 _unused_spill_slot = _max_spills;
209 _max_spills++;
210 }
211 spill_slot = _max_spills;
212 _max_spills += 2;
213
214 } else if (_unused_spill_slot != -1) {
215 // re-use hole that was the result of a previous double-word alignment
216 spill_slot = _unused_spill_slot;
217 _unused_spill_slot = -1;
218
219 } else {
220 spill_slot = _max_spills;
221 _max_spills++;
222 }
223
224 int result = spill_slot + LinearScan::nof_regs + frame_map()->argcount();
225
226 // the class OopMapValue uses only 11 bits for storing the name of the
227 // oop location. So a stack slot bigger than 2^11 leads to an overflow
228 // that is not reported in product builds. Prevent this by checking the
229 // spill slot here (altough this value and the later used location name
230 // are slightly different)
231 if (result > 2000) {
232 bailout("too many stack slots used");
233 }
234
235 return result;
236 }
237
238 void LinearScan::assign_spill_slot(Interval* it) {
239 // assign the canonical spill slot of the parent (if a part of the interval
240 // is already spilled) or allocate a new spill slot
241 if (it->canonical_spill_slot() >= 0) {
242 it->assign_reg(it->canonical_spill_slot());
243 } else {
244 int spill = allocate_spill_slot(type2spill_size[it->type()] == 2);
245 it->set_canonical_spill_slot(spill);
246 it->assign_reg(spill);
247 }
248 }
249
250 void LinearScan::propagate_spill_slots() {
251 if (!frame_map()->finalize_frame(max_spills())) {
252 bailout("frame too large");
253 }
254 }
255
256 // create a new interval with a predefined reg_num
257 // (only used for parent intervals that are created during the building phase)
258 Interval* LinearScan::create_interval(int reg_num) {
259 assert(_intervals.at(reg_num) == NULL, "overwriting exisiting interval");
260
261 Interval* interval = new Interval(reg_num);
262 _intervals.at_put(reg_num, interval);
263
264 // assign register number for precolored intervals
265 if (reg_num < LIR_OprDesc::vreg_base) {
266 interval->assign_reg(reg_num);
267 }
268 return interval;
269 }
270
271 // assign a new reg_num to the interval and append it to the list of intervals
272 // (only used for child intervals that are created during register allocation)
273 void LinearScan::append_interval(Interval* it) {
274 it->set_reg_num(_intervals.length());
275 _intervals.append(it);
276 _new_intervals_from_allocation->append(it);
277 }
278
279 // copy the vreg-flags if an interval is split
280 void LinearScan::copy_register_flags(Interval* from, Interval* to) {
281 if (gen()->is_vreg_flag_set(from->reg_num(), LIRGenerator::byte_reg)) {
282 gen()->set_vreg_flag(to->reg_num(), LIRGenerator::byte_reg);
283 }
284 if (gen()->is_vreg_flag_set(from->reg_num(), LIRGenerator::callee_saved)) {
285 gen()->set_vreg_flag(to->reg_num(), LIRGenerator::callee_saved);
286 }
287
288 // Note: do not copy the must_start_in_memory flag because it is not necessary for child
289 // intervals (only the very beginning of the interval must be in memory)
290 }
291
292
293 // ********** spill move optimization
294 // eliminate moves from register to stack if stack slot is known to be correct
295
296 // called during building of intervals
297 void LinearScan::change_spill_definition_pos(Interval* interval, int def_pos) {
298 assert(interval->is_split_parent(), "can only be called for split parents");
299
300 switch (interval->spill_state()) {
301 case noDefinitionFound:
302 assert(interval->spill_definition_pos() == -1, "must no be set before");
303 interval->set_spill_definition_pos(def_pos);
304 interval->set_spill_state(oneDefinitionFound);
305 break;
306
307 case oneDefinitionFound:
308 assert(def_pos <= interval->spill_definition_pos(), "positions are processed in reverse order when intervals are created");
309 if (def_pos < interval->spill_definition_pos() - 2) {
310 // second definition found, so no spill optimization possible for this interval
311 interval->set_spill_state(noOptimization);
312 } else {
313 // two consecutive definitions (because of two-operand LIR form)
314 assert(block_of_op_with_id(def_pos) == block_of_op_with_id(interval->spill_definition_pos()), "block must be equal");
315 }
316 break;
317
318 case noOptimization:
319 // nothing to do
320 break;
321
322 default:
323 assert(false, "other states not allowed at this time");
324 }
325 }
326
327 // called during register allocation
328 void LinearScan::change_spill_state(Interval* interval, int spill_pos) {
329 switch (interval->spill_state()) {
330 case oneDefinitionFound: {
331 int def_loop_depth = block_of_op_with_id(interval->spill_definition_pos())->loop_depth();
332 int spill_loop_depth = block_of_op_with_id(spill_pos)->loop_depth();
333
334 if (def_loop_depth < spill_loop_depth) {
335 // the loop depth of the spilling position is higher then the loop depth
336 // at the definition of the interval -> move write to memory out of loop
337 // by storing at definitin of the interval
338 interval->set_spill_state(storeAtDefinition);
339 } else {
340 // the interval is currently spilled only once, so for now there is no
341 // reason to store the interval at the definition
342 interval->set_spill_state(oneMoveInserted);
343 }
344 break;
345 }
346
347 case oneMoveInserted: {
348 // the interval is spilled more then once, so it is better to store it to
349 // memory at the definition
350 interval->set_spill_state(storeAtDefinition);
351 break;
352 }
353
354 case storeAtDefinition:
355 case startInMemory:
356 case noOptimization:
357 case noDefinitionFound:
358 // nothing to do
359 break;
360
361 default:
362 assert(false, "other states not allowed at this time");
363 }
364 }
365
366
367 bool LinearScan::must_store_at_definition(const Interval* i) {
368 return i->is_split_parent() && i->spill_state() == storeAtDefinition;
369 }
370
371 // called once before asignment of register numbers
372 void LinearScan::eliminate_spill_moves() {
373 TIME_LINEAR_SCAN(timer_eliminate_spill_moves);
374 TRACE_LINEAR_SCAN(3, tty->print_cr("***** Eliminating unnecessary spill moves"));
375
376 // collect all intervals that must be stored after their definion.
377 // the list is sorted by Interval::spill_definition_pos
378 Interval* interval;
379 Interval* temp_list;
380 create_unhandled_lists(&interval, &temp_list, must_store_at_definition, NULL);
381
382 #ifdef ASSERT
383 Interval* prev = NULL;
384 Interval* temp = interval;
385 while (temp != Interval::end()) {
386 assert(temp->spill_definition_pos() > 0, "invalid spill definition pos");
387 if (prev != NULL) {
388 assert(temp->from() >= prev->from(), "intervals not sorted");
389 assert(temp->spill_definition_pos() >= prev->spill_definition_pos(), "when intervals are sorted by from, then they must also be sorted by spill_definition_pos");
390 }
391
392 assert(temp->canonical_spill_slot() >= LinearScan::nof_regs, "interval has no spill slot assigned");
393 assert(temp->spill_definition_pos() >= temp->from(), "invalid order");
394 assert(temp->spill_definition_pos() <= temp->from() + 2, "only intervals defined once at their start-pos can be optimized");
395
396 TRACE_LINEAR_SCAN(4, tty->print_cr("interval %d (from %d to %d) must be stored at %d", temp->reg_num(), temp->from(), temp->to(), temp->spill_definition_pos()));
397
398 temp = temp->next();
399 }
400 #endif
401
402 LIR_InsertionBuffer insertion_buffer;
403 int num_blocks = block_count();
404 for (int i = 0; i < num_blocks; i++) {
405 BlockBegin* block = block_at(i);
406 LIR_OpList* instructions = block->lir()->instructions_list();
407 int num_inst = instructions->length();
408 bool has_new = false;
409
410 // iterate all instructions of the block. skip the first because it is always a label
411 for (int j = 1; j < num_inst; j++) {
412 LIR_Op* op = instructions->at(j);
413 int op_id = op->id();
414
415 if (op_id == -1) {
416 // remove move from register to stack if the stack slot is guaranteed to be correct.
417 // only moves that have been inserted by LinearScan can be removed.
418 assert(op->code() == lir_move, "only moves can have a op_id of -1");
419 assert(op->as_Op1() != NULL, "move must be LIR_Op1");
420 assert(op->as_Op1()->result_opr()->is_virtual(), "LinearScan inserts only moves to virtual registers");
421
422 LIR_Op1* op1 = (LIR_Op1*)op;
423 Interval* interval = interval_at(op1->result_opr()->vreg_number());
424
425 if (interval->assigned_reg() >= LinearScan::nof_regs && interval->always_in_memory()) {
426 // move target is a stack slot that is always correct, so eliminate instruction
427 TRACE_LINEAR_SCAN(4, tty->print_cr("eliminating move from interval %d to %d", op1->in_opr()->vreg_number(), op1->result_opr()->vreg_number()));
428 instructions->at_put(j, NULL); // NULL-instructions are deleted by assign_reg_num
429 }
430
431 } else {
432 // insert move from register to stack just after the beginning of the interval
433 assert(interval == Interval::end() || interval->spill_definition_pos() >= op_id, "invalid order");
434 assert(interval == Interval::end() || (interval->is_split_parent() && interval->spill_state() == storeAtDefinition), "invalid interval");
435
436 while (interval != Interval::end() && interval->spill_definition_pos() == op_id) {
437 if (!has_new) {
438 // prepare insertion buffer (appended when all instructions of the block are processed)
439 insertion_buffer.init(block->lir());
440 has_new = true;
441 }
442
443 LIR_Opr from_opr = operand_for_interval(interval);
444 LIR_Opr to_opr = canonical_spill_opr(interval);
445 assert(from_opr->is_fixed_cpu() || from_opr->is_fixed_fpu(), "from operand must be a register");
446 assert(to_opr->is_stack(), "to operand must be a stack slot");
447
448 insertion_buffer.move(j, from_opr, to_opr);
449 TRACE_LINEAR_SCAN(4, tty->print_cr("inserting move after definition of interval %d to stack slot %d at op_id %d", interval->reg_num(), interval->canonical_spill_slot() - LinearScan::nof_regs, op_id));
450
451 interval = interval->next();
452 }
453 }
454 } // end of instruction iteration
455
456 if (has_new) {
457 block->lir()->append(&insertion_buffer);
458 }
459 } // end of block iteration
460
461 assert(interval == Interval::end(), "missed an interval");
462 }
463
464
465 // ********** Phase 1: number all instructions in all blocks
466 // Compute depth-first and linear scan block orders, and number LIR_Op nodes for linear scan.
467
468 void LinearScan::number_instructions() {
469 {
470 // dummy-timer to measure the cost of the timer itself
471 // (this time is then subtracted from all other timers to get the real value)
472 TIME_LINEAR_SCAN(timer_do_nothing);
473 }
474 TIME_LINEAR_SCAN(timer_number_instructions);
475
476 // Assign IDs to LIR nodes and build a mapping, lir_ops, from ID to LIR_Op node.
477 int num_blocks = block_count();
478 int num_instructions = 0;
479 int i;
480 for (i = 0; i < num_blocks; i++) {
481 num_instructions += block_at(i)->lir()->instructions_list()->length();
482 }
483
484 // initialize with correct length
485 _lir_ops = LIR_OpArray(num_instructions);
486 _block_of_op = BlockBeginArray(num_instructions);
487
488 int op_id = 0;
489 int idx = 0;
490
491 for (i = 0; i < num_blocks; i++) {
492 BlockBegin* block = block_at(i);
493 block->set_first_lir_instruction_id(op_id);
494 LIR_OpList* instructions = block->lir()->instructions_list();
495
496 int num_inst = instructions->length();
497 for (int j = 0; j < num_inst; j++) {
498 LIR_Op* op = instructions->at(j);
499 op->set_id(op_id);
500
501 _lir_ops.at_put(idx, op);
502 _block_of_op.at_put(idx, block);
503 assert(lir_op_with_id(op_id) == op, "must match");
504
505 idx++;
506 op_id += 2; // numbering of lir_ops by two
507 }
508 block->set_last_lir_instruction_id(op_id - 2);
509 }
510 assert(idx == num_instructions, "must match");
511 assert(idx * 2 == op_id, "must match");
512
513 _has_call = BitMap(num_instructions); _has_call.clear();
514 _has_info = BitMap(num_instructions); _has_info.clear();
515 }
516
517
518 // ********** Phase 2: compute local live sets separately for each block
519 // (sets live_gen and live_kill for each block)
520
521 void LinearScan::set_live_gen_kill(Value value, LIR_Op* op, BitMap& live_gen, BitMap& live_kill) {
522 LIR_Opr opr = value->operand();
523 Constant* con = value->as_Constant();
524
525 // check some asumptions about debug information
526 assert(!value->type()->is_illegal(), "if this local is used by the interpreter it shouldn't be of indeterminate type");
527 assert(con == NULL || opr->is_virtual() || opr->is_constant() || opr->is_illegal(), "asumption: Constant instructions have only constant operands");
528 assert(con != NULL || opr->is_virtual(), "asumption: non-Constant instructions have only virtual operands");
529
530 if ((con == NULL || con->is_pinned()) && opr->is_register()) {
531 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
532 int reg = opr->vreg_number();
533 if (!live_kill.at(reg)) {
534 live_gen.set_bit(reg);
535 TRACE_LINEAR_SCAN(4, tty->print_cr(" Setting live_gen for value %c%d, LIR op_id %d, register number %d", value->type()->tchar(), value->id(), op->id(), reg));
536 }
537 }
538 }
539
540
541 void LinearScan::compute_local_live_sets() {
542 TIME_LINEAR_SCAN(timer_compute_local_live_sets);
543
544 int num_blocks = block_count();
545 int live_size = live_set_size();
546 bool local_has_fpu_registers = false;
547 int local_num_calls = 0;
548 LIR_OpVisitState visitor;
549
550 BitMap2D local_interval_in_loop = BitMap2D(_num_virtual_regs, num_loops());
551 local_interval_in_loop.clear();
552
553 // iterate all blocks
554 for (int i = 0; i < num_blocks; i++) {
555 BlockBegin* block = block_at(i);
556
557 BitMap live_gen(live_size); live_gen.clear();
558 BitMap live_kill(live_size); live_kill.clear();
559
560 if (block->is_set(BlockBegin::exception_entry_flag)) {
561 // Phi functions at the begin of an exception handler are
562 // implicitly defined (= killed) at the beginning of the block.
563 for_each_phi_fun(block, phi,
564 live_kill.set_bit(phi->operand()->vreg_number())
565 );
566 }
567
568 LIR_OpList* instructions = block->lir()->instructions_list();
569 int num_inst = instructions->length();
570
571 // iterate all instructions of the block. skip the first because it is always a label
572 assert(visitor.no_operands(instructions->at(0)), "first operation must always be a label");
573 for (int j = 1; j < num_inst; j++) {
574 LIR_Op* op = instructions->at(j);
575
576 // visit operation to collect all operands
577 visitor.visit(op);
578
579 if (visitor.has_call()) {
580 _has_call.set_bit(op->id() >> 1);
581 local_num_calls++;
582 }
583 if (visitor.info_count() > 0) {
584 _has_info.set_bit(op->id() >> 1);
585 }
586
587 // iterate input operands of instruction
588 int k, n, reg;
589 n = visitor.opr_count(LIR_OpVisitState::inputMode);
590 for (k = 0; k < n; k++) {
591 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::inputMode, k);
592 assert(opr->is_register(), "visitor should only return register operands");
593
594 if (opr->is_virtual_register()) {
595 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
596 reg = opr->vreg_number();
597 if (!live_kill.at(reg)) {
598 live_gen.set_bit(reg);
599 TRACE_LINEAR_SCAN(4, tty->print_cr(" Setting live_gen for register %d at instruction %d", reg, op->id()));
600 }
601 if (block->loop_index() >= 0) {
602 local_interval_in_loop.set_bit(reg, block->loop_index());
603 }
604 local_has_fpu_registers = local_has_fpu_registers || opr->is_virtual_fpu();
605 }
606
607 #ifdef ASSERT
608 // fixed intervals are never live at block boundaries, so
609 // they need not be processed in live sets.
610 // this is checked by these assertions to be sure about it.
611 // the entry block may have incoming values in registers, which is ok.
612 if (!opr->is_virtual_register() && block != ir()->start()) {
613 reg = reg_num(opr);
614 if (is_processed_reg_num(reg)) {
615 assert(live_kill.at(reg), "using fixed register that is not defined in this block");
616 }
617 reg = reg_numHi(opr);
618 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
619 assert(live_kill.at(reg), "using fixed register that is not defined in this block");
620 }
621 }
622 #endif
623 }
624
625 // Add uses of live locals from interpreter's point of view for proper debug information generation
626 n = visitor.info_count();
627 for (k = 0; k < n; k++) {
628 CodeEmitInfo* info = visitor.info_at(k);
629 ValueStack* stack = info->stack();
630 for_each_state_value(stack, value,
631 set_live_gen_kill(value, op, live_gen, live_kill)
632 );
633 }
634
635 // iterate temp operands of instruction
636 n = visitor.opr_count(LIR_OpVisitState::tempMode);
637 for (k = 0; k < n; k++) {
638 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::tempMode, k);
639 assert(opr->is_register(), "visitor should only return register operands");
640
641 if (opr->is_virtual_register()) {
642 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
643 reg = opr->vreg_number();
644 live_kill.set_bit(reg);
645 if (block->loop_index() >= 0) {
646 local_interval_in_loop.set_bit(reg, block->loop_index());
647 }
648 local_has_fpu_registers = local_has_fpu_registers || opr->is_virtual_fpu();
649 }
650
651 #ifdef ASSERT
652 // fixed intervals are never live at block boundaries, so
653 // they need not be processed in live sets
654 // process them only in debug mode so that this can be checked
655 if (!opr->is_virtual_register()) {
656 reg = reg_num(opr);
657 if (is_processed_reg_num(reg)) {
658 live_kill.set_bit(reg_num(opr));
659 }
660 reg = reg_numHi(opr);
661 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
662 live_kill.set_bit(reg);
663 }
664 }
665 #endif
666 }
667
668 // iterate output operands of instruction
669 n = visitor.opr_count(LIR_OpVisitState::outputMode);
670 for (k = 0; k < n; k++) {
671 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::outputMode, k);
672 assert(opr->is_register(), "visitor should only return register operands");
673
674 if (opr->is_virtual_register()) {
675 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
676 reg = opr->vreg_number();
677 live_kill.set_bit(reg);
678 if (block->loop_index() >= 0) {
679 local_interval_in_loop.set_bit(reg, block->loop_index());
680 }
681 local_has_fpu_registers = local_has_fpu_registers || opr->is_virtual_fpu();
682 }
683
684 #ifdef ASSERT
685 // fixed intervals are never live at block boundaries, so
686 // they need not be processed in live sets
687 // process them only in debug mode so that this can be checked
688 if (!opr->is_virtual_register()) {
689 reg = reg_num(opr);
690 if (is_processed_reg_num(reg)) {
691 live_kill.set_bit(reg_num(opr));
692 }
693 reg = reg_numHi(opr);
694 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
695 live_kill.set_bit(reg);
696 }
697 }
698 #endif
699 }
700 } // end of instruction iteration
701
702 block->set_live_gen (live_gen);
703 block->set_live_kill(live_kill);
704 block->set_live_in (BitMap(live_size)); block->live_in().clear();
705 block->set_live_out (BitMap(live_size)); block->live_out().clear();
706
707 TRACE_LINEAR_SCAN(4, tty->print("live_gen B%d ", block->block_id()); print_bitmap(block->live_gen()));
708 TRACE_LINEAR_SCAN(4, tty->print("live_kill B%d ", block->block_id()); print_bitmap(block->live_kill()));
709 } // end of block iteration
710
711 // propagate local calculated information into LinearScan object
712 _has_fpu_registers = local_has_fpu_registers;
713 compilation()->set_has_fpu_code(local_has_fpu_registers);
714
715 _num_calls = local_num_calls;
716 _interval_in_loop = local_interval_in_loop;
717 }
718
719
720 // ********** Phase 3: perform a backward dataflow analysis to compute global live sets
721 // (sets live_in and live_out for each block)
722
723 void LinearScan::compute_global_live_sets() {
724 TIME_LINEAR_SCAN(timer_compute_global_live_sets);
725
726 int num_blocks = block_count();
727 bool change_occurred;
728 bool change_occurred_in_block;
729 int iteration_count = 0;
730 BitMap live_out(live_set_size()); live_out.clear(); // scratch set for calculations
731
732 // Perform a backward dataflow analysis to compute live_out and live_in for each block.
733 // The loop is executed until a fixpoint is reached (no changes in an iteration)
734 // Exception handlers must be processed because not all live values are
735 // present in the state array, e.g. because of global value numbering
736 do {
737 change_occurred = false;
738
739 // iterate all blocks in reverse order
740 for (int i = num_blocks - 1; i >= 0; i--) {
741 BlockBegin* block = block_at(i);
742
743 change_occurred_in_block = false;
744
745 // live_out(block) is the union of live_in(sux), for successors sux of block
746 int n = block->number_of_sux();
747 int e = block->number_of_exception_handlers();
748 if (n + e > 0) {
749 // block has successors
750 if (n > 0) {
751 live_out.set_from(block->sux_at(0)->live_in());
752 for (int j = 1; j < n; j++) {
753 live_out.set_union(block->sux_at(j)->live_in());
754 }
755 } else {
756 live_out.clear();
757 }
758 for (int j = 0; j < e; j++) {
759 live_out.set_union(block->exception_handler_at(j)->live_in());
760 }
761
762 if (!block->live_out().is_same(live_out)) {
763 // A change occurred. Swap the old and new live out sets to avoid copying.
764 BitMap temp = block->live_out();
765 block->set_live_out(live_out);
766 live_out = temp;
767
768 change_occurred = true;
769 change_occurred_in_block = true;
770 }
771 }
772
773 if (iteration_count == 0 || change_occurred_in_block) {
774 // live_in(block) is the union of live_gen(block) with (live_out(block) & !live_kill(block))
775 // note: live_in has to be computed only in first iteration or if live_out has changed!
776 BitMap live_in = block->live_in();
777 live_in.set_from(block->live_out());
778 live_in.set_difference(block->live_kill());
779 live_in.set_union(block->live_gen());
780 }
781
782 #ifndef PRODUCT
783 if (TraceLinearScanLevel >= 4) {
784 char c = ' ';
785 if (iteration_count == 0 || change_occurred_in_block) {
786 c = '*';
787 }
788 tty->print("(%d) live_in%c B%d ", iteration_count, c, block->block_id()); print_bitmap(block->live_in());
789 tty->print("(%d) live_out%c B%d ", iteration_count, c, block->block_id()); print_bitmap(block->live_out());
790 }
791 #endif
792 }
793 iteration_count++;
794
795 if (change_occurred && iteration_count > 50) {
796 BAILOUT("too many iterations in compute_global_live_sets");
797 }
798 } while (change_occurred);
799
800
801 #ifdef ASSERT
802 // check that fixed intervals are not live at block boundaries
803 // (live set must be empty at fixed intervals)
804 for (int i = 0; i < num_blocks; i++) {
805 BlockBegin* block = block_at(i);
806 for (int j = 0; j < LIR_OprDesc::vreg_base; j++) {
807 assert(block->live_in().at(j) == false, "live_in set of fixed register must be empty");
808 assert(block->live_out().at(j) == false, "live_out set of fixed register must be empty");
809 assert(block->live_gen().at(j) == false, "live_gen set of fixed register must be empty");
810 }
811 }
812 #endif
813
814 // check that the live_in set of the first block is empty
815 BitMap live_in_args(ir()->start()->live_in().size());
816 live_in_args.clear();
817 if (!ir()->start()->live_in().is_same(live_in_args)) {
818 #ifdef ASSERT
819 tty->print_cr("Error: live_in set of first block must be empty (when this fails, virtual registers are used before they are defined)");
820 tty->print_cr("affected registers:");
821 print_bitmap(ir()->start()->live_in());
822
823 // print some additional information to simplify debugging
824 for (unsigned int i = 0; i < ir()->start()->live_in().size(); i++) {
825 if (ir()->start()->live_in().at(i)) {
826 Instruction* instr = gen()->instruction_for_vreg(i);
827 tty->print_cr("* vreg %d (HIR instruction %c%d)", i, instr == NULL ? ' ' : instr->type()->tchar(), instr == NULL ? 0 : instr->id());
828
829 for (int j = 0; j < num_blocks; j++) {
830 BlockBegin* block = block_at(j);
831 if (block->live_gen().at(i)) {
832 tty->print_cr(" used in block B%d", block->block_id());
833 }
834 if (block->live_kill().at(i)) {
835 tty->print_cr(" defined in block B%d", block->block_id());
836 }
837 }
838 }
839 }
840
841 #endif
842 // when this fails, virtual registers are used before they are defined.
843 assert(false, "live_in set of first block must be empty");
844 // bailout of if this occurs in product mode.
845 bailout("live_in set of first block not empty");
846 }
847 }
848
849
850 // ********** Phase 4: build intervals
851 // (fills the list _intervals)
852
853 void LinearScan::add_use(Value value, int from, int to, IntervalUseKind use_kind) {
854 assert(!value->type()->is_illegal(), "if this value is used by the interpreter it shouldn't be of indeterminate type");
855 LIR_Opr opr = value->operand();
856 Constant* con = value->as_Constant();
857
858 if ((con == NULL || con->is_pinned()) && opr->is_register()) {
859 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
860 add_use(opr, from, to, use_kind);
861 }
862 }
863
864
865 void LinearScan::add_def(LIR_Opr opr, int def_pos, IntervalUseKind use_kind) {
866 TRACE_LINEAR_SCAN(2, tty->print(" def "); opr->print(tty); tty->print_cr(" def_pos %d (%d)", def_pos, use_kind));
867 assert(opr->is_register(), "should not be called otherwise");
868
869 if (opr->is_virtual_register()) {
870 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
871 add_def(opr->vreg_number(), def_pos, use_kind, opr->type_register());
872
873 } else {
874 int reg = reg_num(opr);
875 if (is_processed_reg_num(reg)) {
876 add_def(reg, def_pos, use_kind, opr->type_register());
877 }
878 reg = reg_numHi(opr);
879 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
880 add_def(reg, def_pos, use_kind, opr->type_register());
881 }
882 }
883 }
884
885 void LinearScan::add_use(LIR_Opr opr, int from, int to, IntervalUseKind use_kind) {
886 TRACE_LINEAR_SCAN(2, tty->print(" use "); opr->print(tty); tty->print_cr(" from %d to %d (%d)", from, to, use_kind));
887 assert(opr->is_register(), "should not be called otherwise");
888
889 if (opr->is_virtual_register()) {
890 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
891 add_use(opr->vreg_number(), from, to, use_kind, opr->type_register());
892
893 } else {
894 int reg = reg_num(opr);
895 if (is_processed_reg_num(reg)) {
896 add_use(reg, from, to, use_kind, opr->type_register());
897 }
898 reg = reg_numHi(opr);
899 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
900 add_use(reg, from, to, use_kind, opr->type_register());
901 }
902 }
903 }
904
905 void LinearScan::add_temp(LIR_Opr opr, int temp_pos, IntervalUseKind use_kind) {
906 TRACE_LINEAR_SCAN(2, tty->print(" temp "); opr->print(tty); tty->print_cr(" temp_pos %d (%d)", temp_pos, use_kind));
907 assert(opr->is_register(), "should not be called otherwise");
908
909 if (opr->is_virtual_register()) {
910 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
911 add_temp(opr->vreg_number(), temp_pos, use_kind, opr->type_register());
912
913 } else {
914 int reg = reg_num(opr);
915 if (is_processed_reg_num(reg)) {
916 add_temp(reg, temp_pos, use_kind, opr->type_register());
917 }
918 reg = reg_numHi(opr);
919 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
920 add_temp(reg, temp_pos, use_kind, opr->type_register());
921 }
922 }
923 }
924
925
926 void LinearScan::add_def(int reg_num, int def_pos, IntervalUseKind use_kind, BasicType type) {
927 Interval* interval = interval_at(reg_num);
928 if (interval != NULL) {
929 assert(interval->reg_num() == reg_num, "wrong interval");
930
931 if (type != T_ILLEGAL) {
932 interval->set_type(type);
933 }
934
935 Range* r = interval->first();
936 if (r->from() <= def_pos) {
937 // Update the starting point (when a range is first created for a use, its
938 // start is the beginning of the current block until a def is encountered.)
939 r->set_from(def_pos);
940 interval->add_use_pos(def_pos, use_kind);
941
942 } else {
943 // Dead value - make vacuous interval
944 // also add use_kind for dead intervals
945 interval->add_range(def_pos, def_pos + 1);
946 interval->add_use_pos(def_pos, use_kind);
947 TRACE_LINEAR_SCAN(2, tty->print_cr("Warning: def of reg %d at %d occurs without use", reg_num, def_pos));
948 }
949
950 } else {
951 // Dead value - make vacuous interval
952 // also add use_kind for dead intervals
953 interval = create_interval(reg_num);
954 if (type != T_ILLEGAL) {
955 interval->set_type(type);
956 }
957
958 interval->add_range(def_pos, def_pos + 1);
959 interval->add_use_pos(def_pos, use_kind);
960 TRACE_LINEAR_SCAN(2, tty->print_cr("Warning: dead value %d at %d in live intervals", reg_num, def_pos));
961 }
962
963 change_spill_definition_pos(interval, def_pos);
964 if (use_kind == noUse && interval->spill_state() <= startInMemory) {
965 // detection of method-parameters and roundfp-results
966 // TODO: move this directly to position where use-kind is computed
967 interval->set_spill_state(startInMemory);
968 }
969 }
970
971 void LinearScan::add_use(int reg_num, int from, int to, IntervalUseKind use_kind, BasicType type) {
972 Interval* interval = interval_at(reg_num);
973 if (interval == NULL) {
974 interval = create_interval(reg_num);
975 }
976 assert(interval->reg_num() == reg_num, "wrong interval");
977
978 if (type != T_ILLEGAL) {
979 interval->set_type(type);
980 }
981
982 interval->add_range(from, to);
983 interval->add_use_pos(to, use_kind);
984 }
985
986 void LinearScan::add_temp(int reg_num, int temp_pos, IntervalUseKind use_kind, BasicType type) {
987 Interval* interval = interval_at(reg_num);
988 if (interval == NULL) {
989 interval = create_interval(reg_num);
990 }
991 assert(interval->reg_num() == reg_num, "wrong interval");
992
993 if (type != T_ILLEGAL) {
994 interval->set_type(type);
995 }
996
997 interval->add_range(temp_pos, temp_pos + 1);
998 interval->add_use_pos(temp_pos, use_kind);
999 }
1000
1001
1002 // the results of this functions are used for optimizing spilling and reloading
1003 // if the functions return shouldHaveRegister and the interval is spilled,
1004 // it is not reloaded to a register.
1005 IntervalUseKind LinearScan::use_kind_of_output_operand(LIR_Op* op, LIR_Opr opr) {
1006 if (op->code() == lir_move) {
1007 assert(op->as_Op1() != NULL, "lir_move must be LIR_Op1");
1008 LIR_Op1* move = (LIR_Op1*)op;
1009 LIR_Opr res = move->result_opr();
1010 bool result_in_memory = res->is_virtual() && gen()->is_vreg_flag_set(res->vreg_number(), LIRGenerator::must_start_in_memory);
1011
1012 if (result_in_memory) {
1013 // Begin of an interval with must_start_in_memory set.
1014 // This interval will always get a stack slot first, so return noUse.
1015 return noUse;
1016
1017 } else if (move->in_opr()->is_stack()) {
1018 // method argument (condition must be equal to handle_method_arguments)
1019 return noUse;
1020
1021 } else if (move->in_opr()->is_register() && move->result_opr()->is_register()) {
1022 // Move from register to register
1023 if (block_of_op_with_id(op->id())->is_set(BlockBegin::osr_entry_flag)) {
1024 // special handling of phi-function moves inside osr-entry blocks
1025 // input operand must have a register instead of output operand (leads to better register allocation)
1026 return shouldHaveRegister;
1027 }
1028 }
1029 }
1030
1031 if (opr->is_virtual() &&
1032 gen()->is_vreg_flag_set(opr->vreg_number(), LIRGenerator::must_start_in_memory)) {
1033 // result is a stack-slot, so prevent immediate reloading
1034 return noUse;
1035 }
1036
1037 // all other operands require a register
1038 return mustHaveRegister;
1039 }
1040
1041 IntervalUseKind LinearScan::use_kind_of_input_operand(LIR_Op* op, LIR_Opr opr) {
1042 if (op->code() == lir_move) {
1043 assert(op->as_Op1() != NULL, "lir_move must be LIR_Op1");
1044 LIR_Op1* move = (LIR_Op1*)op;
1045 LIR_Opr res = move->result_opr();
1046 bool result_in_memory = res->is_virtual() && gen()->is_vreg_flag_set(res->vreg_number(), LIRGenerator::must_start_in_memory);
1047
1048 if (result_in_memory) {
1049 // Move to an interval with must_start_in_memory set.
1050 // To avoid moves from stack to stack (not allowed) force the input operand to a register
1051 return mustHaveRegister;
1052
1053 } else if (move->in_opr()->is_register() && move->result_opr()->is_register()) {
1054 // Move from register to register
1055 if (block_of_op_with_id(op->id())->is_set(BlockBegin::osr_entry_flag)) {
1056 // special handling of phi-function moves inside osr-entry blocks
1057 // input operand must have a register instead of output operand (leads to better register allocation)
1058 return mustHaveRegister;
1059 }
1060
1061 // The input operand is not forced to a register (moves from stack to register are allowed),
1062 // but it is faster if the input operand is in a register
1063 return shouldHaveRegister;
1064 }
1065 }
1066
1067
1068 #ifdef X86
1069 if (op->code() == lir_cmove) {
1070 // conditional moves can handle stack operands
1071 assert(op->result_opr()->is_register(), "result must always be in a register");
1072 return shouldHaveRegister;
1073 }
1074
1075 // optimizations for second input operand of arithmehtic operations on Intel
1076 // this operand is allowed to be on the stack in some cases
1077 BasicType opr_type = opr->type_register();
1078 if (opr_type == T_FLOAT || opr_type == T_DOUBLE) {
1079 if ((UseSSE == 1 && opr_type == T_FLOAT) || UseSSE >= 2) {
1080 // SSE float instruction (T_DOUBLE only supported with SSE2)
1081 switch (op->code()) {
1082 case lir_cmp:
1083 case lir_add:
1084 case lir_sub:
1085 case lir_mul:
1086 case lir_div:
1087 {
1088 assert(op->as_Op2() != NULL, "must be LIR_Op2");
1089 LIR_Op2* op2 = (LIR_Op2*)op;
1090 if (op2->in_opr1() != op2->in_opr2() && op2->in_opr2() == opr) {
1091 assert((op2->result_opr()->is_register() || op->code() == lir_cmp) && op2->in_opr1()->is_register(), "cannot mark second operand as stack if others are not in register");
1092 return shouldHaveRegister;
1093 }
1094 }
1095 }
1096 } else {
1097 // FPU stack float instruction
1098 switch (op->code()) {
1099 case lir_add:
1100 case lir_sub:
1101 case lir_mul:
1102 case lir_div:
1103 {
1104 assert(op->as_Op2() != NULL, "must be LIR_Op2");
1105 LIR_Op2* op2 = (LIR_Op2*)op;
1106 if (op2->in_opr1() != op2->in_opr2() && op2->in_opr2() == opr) {
1107 assert((op2->result_opr()->is_register() || op->code() == lir_cmp) && op2->in_opr1()->is_register(), "cannot mark second operand as stack if others are not in register");
1108 return shouldHaveRegister;
1109 }
1110 }
1111 }
1112 }
1113
1114 } else if (opr_type != T_LONG) {
1115 // integer instruction (note: long operands must always be in register)
1116 switch (op->code()) {
1117 case lir_cmp:
1118 case lir_add:
1119 case lir_sub:
1120 case lir_logic_and:
1121 case lir_logic_or:
1122 case lir_logic_xor:
1123 {
1124 assert(op->as_Op2() != NULL, "must be LIR_Op2");
1125 LIR_Op2* op2 = (LIR_Op2*)op;
1126 if (op2->in_opr1() != op2->in_opr2() && op2->in_opr2() == opr) {
1127 assert((op2->result_opr()->is_register() || op->code() == lir_cmp) && op2->in_opr1()->is_register(), "cannot mark second operand as stack if others are not in register");
1128 return shouldHaveRegister;
1129 }
1130 }
1131 }
1132 }
1133 #endif // X86
1134
1135 // all other operands require a register
1136 return mustHaveRegister;
1137 }
1138
1139
1140 void LinearScan::handle_method_arguments(LIR_Op* op) {
1141 // special handling for method arguments (moves from stack to virtual register):
1142 // the interval gets no register assigned, but the stack slot.
1143 // it is split before the first use by the register allocator.
1144
1145 if (op->code() == lir_move) {
1146 assert(op->as_Op1() != NULL, "must be LIR_Op1");
1147 LIR_Op1* move = (LIR_Op1*)op;
1148
1149 if (move->in_opr()->is_stack()) {
1150 #ifdef ASSERT
1151 int arg_size = compilation()->method()->arg_size();
1152 LIR_Opr o = move->in_opr();
1153 if (o->is_single_stack()) {
1154 assert(o->single_stack_ix() >= 0 && o->single_stack_ix() < arg_size, "out of range");
1155 } else if (o->is_double_stack()) {
1156 assert(o->double_stack_ix() >= 0 && o->double_stack_ix() < arg_size, "out of range");
1157 } else {
1158 ShouldNotReachHere();
1159 }
1160
1161 assert(move->id() > 0, "invalid id");
1162 assert(block_of_op_with_id(move->id())->number_of_preds() == 0, "move from stack must be in first block");
1163 assert(move->result_opr()->is_virtual(), "result of move must be a virtual register");
1164
1165 TRACE_LINEAR_SCAN(4, tty->print_cr("found move from stack slot %d to vreg %d", o->is_single_stack() ? o->single_stack_ix() : o->double_stack_ix(), reg_num(move->result_opr())));
1166 #endif
1167
1168 Interval* interval = interval_at(reg_num(move->result_opr()));
1169
1170 int stack_slot = LinearScan::nof_regs + (move->in_opr()->is_single_stack() ? move->in_opr()->single_stack_ix() : move->in_opr()->double_stack_ix());
1171 interval->set_canonical_spill_slot(stack_slot);
1172 interval->assign_reg(stack_slot);
1173 }
1174 }
1175 }
1176
1177 void LinearScan::handle_doubleword_moves(LIR_Op* op) {
1178 // special handling for doubleword move from memory to register:
1179 // in this case the registers of the input address and the result
1180 // registers must not overlap -> add a temp range for the input registers
1181 if (op->code() == lir_move) {
1182 assert(op->as_Op1() != NULL, "must be LIR_Op1");
1183 LIR_Op1* move = (LIR_Op1*)op;
1184
1185 if (move->result_opr()->is_double_cpu() && move->in_opr()->is_pointer()) {
1186 LIR_Address* address = move->in_opr()->as_address_ptr();
1187 if (address != NULL) {
1188 if (address->base()->is_valid()) {
1189 add_temp(address->base(), op->id(), noUse);
1190 }
1191 if (address->index()->is_valid()) {
1192 add_temp(address->index(), op->id(), noUse);
1193 }
1194 }
1195 }
1196 }
1197 }
1198
1199 void LinearScan::add_register_hints(LIR_Op* op) {
1200 switch (op->code()) {
1201 case lir_move: // fall through
1202 case lir_convert: {
1203 assert(op->as_Op1() != NULL, "lir_move, lir_convert must be LIR_Op1");
1204 LIR_Op1* move = (LIR_Op1*)op;
1205
1206 LIR_Opr move_from = move->in_opr();
1207 LIR_Opr move_to = move->result_opr();
1208
1209 if (move_to->is_register() && move_from->is_register()) {
1210 Interval* from = interval_at(reg_num(move_from));
1211 Interval* to = interval_at(reg_num(move_to));
1212 if (from != NULL && to != NULL) {
1213 to->set_register_hint(from);
1214 TRACE_LINEAR_SCAN(4, tty->print_cr("operation at op_id %d: added hint from interval %d to %d", move->id(), from->reg_num(), to->reg_num()));
1215 }
1216 }
1217 break;
1218 }
1219 case lir_cmove: {
1220 assert(op->as_Op2() != NULL, "lir_cmove must be LIR_Op2");
1221 LIR_Op2* cmove = (LIR_Op2*)op;
1222
1223 LIR_Opr move_from = cmove->in_opr1();
1224 LIR_Opr move_to = cmove->result_opr();
1225
1226 if (move_to->is_register() && move_from->is_register()) {
1227 Interval* from = interval_at(reg_num(move_from));
1228 Interval* to = interval_at(reg_num(move_to));
1229 if (from != NULL && to != NULL) {
1230 to->set_register_hint(from);
1231 TRACE_LINEAR_SCAN(4, tty->print_cr("operation at op_id %d: added hint from interval %d to %d", cmove->id(), from->reg_num(), to->reg_num()));
1232 }
1233 }
1234 break;
1235 }
1236 }
1237 }
1238
1239
1240 void LinearScan::build_intervals() {
1241 TIME_LINEAR_SCAN(timer_build_intervals);
1242
1243 // initialize interval list with expected number of intervals
1244 // (32 is added to have some space for split children without having to resize the list)
1245 _intervals = IntervalList(num_virtual_regs() + 32);
1246 // initialize all slots that are used by build_intervals
1247 _intervals.at_put_grow(num_virtual_regs() - 1, NULL, NULL);
1248
1249 // create a list with all caller-save registers (cpu, fpu, xmm)
1250 // when an instruction is a call, a temp range is created for all these registers
1251 int num_caller_save_registers = 0;
1252 int caller_save_registers[LinearScan::nof_regs];
1253
1254 int i;
1255 for (i = 0; i < FrameMap::nof_caller_save_cpu_regs; i++) {
1256 LIR_Opr opr = FrameMap::caller_save_cpu_reg_at(i);
1257 assert(opr->is_valid() && opr->is_register(), "FrameMap should not return invalid operands");
1258 assert(reg_numHi(opr) == -1, "missing addition of range for hi-register");
1259 caller_save_registers[num_caller_save_registers++] = reg_num(opr);
1260 }
1261
1262 // temp ranges for fpu registers are only created when the method has
1263 // virtual fpu operands. Otherwise no allocation for fpu registers is
1264 // perfomed and so the temp ranges would be useless
1265 if (has_fpu_registers()) {
1266 #ifdef X86
1267 if (UseSSE < 2) {
1268 #endif
1269 for (i = 0; i < FrameMap::nof_caller_save_fpu_regs; i++) {
1270 LIR_Opr opr = FrameMap::caller_save_fpu_reg_at(i);
1271 assert(opr->is_valid() && opr->is_register(), "FrameMap should not return invalid operands");
1272 assert(reg_numHi(opr) == -1, "missing addition of range for hi-register");
1273 caller_save_registers[num_caller_save_registers++] = reg_num(opr);
1274 }
1275 #ifdef X86
1276 }
1277 if (UseSSE > 0) {
1278 for (i = 0; i < FrameMap::nof_caller_save_xmm_regs; i++) {
1279 LIR_Opr opr = FrameMap::caller_save_xmm_reg_at(i);
1280 assert(opr->is_valid() && opr->is_register(), "FrameMap should not return invalid operands");
1281 assert(reg_numHi(opr) == -1, "missing addition of range for hi-register");
1282 caller_save_registers[num_caller_save_registers++] = reg_num(opr);
1283 }
1284 }
1285 #endif
1286 }
1287 assert(num_caller_save_registers <= LinearScan::nof_regs, "out of bounds");
1288
1289
1290 LIR_OpVisitState visitor;
1291
1292 // iterate all blocks in reverse order
1293 for (i = block_count() - 1; i >= 0; i--) {
1294 BlockBegin* block = block_at(i);
1295 LIR_OpList* instructions = block->lir()->instructions_list();
1296 int block_from = block->first_lir_instruction_id();
1297 int block_to = block->last_lir_instruction_id();
1298
1299 assert(block_from == instructions->at(0)->id(), "must be");
1300 assert(block_to == instructions->at(instructions->length() - 1)->id(), "must be");
1301
1302 // Update intervals for registers live at the end of this block;
1303 BitMap live = block->live_out();
1304 int size = (int)live.size();
1305 for (int number = (int)live.get_next_one_offset(0, size); number < size; number = (int)live.get_next_one_offset(number + 1, size)) {
1306 assert(live.at(number), "should not stop here otherwise");
1307 assert(number >= LIR_OprDesc::vreg_base, "fixed intervals must not be live on block bounds");
1308 TRACE_LINEAR_SCAN(2, tty->print_cr("live in %d to %d", number, block_to + 2));
1309
1310 add_use(number, block_from, block_to + 2, noUse, T_ILLEGAL);
1311
1312 // add special use positions for loop-end blocks when the
1313 // interval is used anywhere inside this loop. It's possible
1314 // that the block was part of a non-natural loop, so it might
1315 // have an invalid loop index.
1316 if (block->is_set(BlockBegin::linear_scan_loop_end_flag) &&
1317 block->loop_index() != -1 &&
1318 is_interval_in_loop(number, block->loop_index())) {
1319 interval_at(number)->add_use_pos(block_to + 1, loopEndMarker);
1320 }
1321 }
1322
1323 // iterate all instructions of the block in reverse order.
1324 // skip the first instruction because it is always a label
1325 // definitions of intervals are processed before uses
1326 assert(visitor.no_operands(instructions->at(0)), "first operation must always be a label");
1327 for (int j = instructions->length() - 1; j >= 1; j--) {
1328 LIR_Op* op = instructions->at(j);
1329 int op_id = op->id();
1330
1331 // visit operation to collect all operands
1332 visitor.visit(op);
1333
1334 // add a temp range for each register if operation destroys caller-save registers
1335 if (visitor.has_call()) {
1336 for (int k = 0; k < num_caller_save_registers; k++) {
1337 add_temp(caller_save_registers[k], op_id, noUse, T_ILLEGAL);
1338 }
1339 TRACE_LINEAR_SCAN(4, tty->print_cr("operation destroys all caller-save registers"));
1340 }
1341
1342 // Add any platform dependent temps
1343 pd_add_temps(op);
1344
1345 // visit definitions (output and temp operands)
1346 int k, n;
1347 n = visitor.opr_count(LIR_OpVisitState::outputMode);
1348 for (k = 0; k < n; k++) {
1349 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::outputMode, k);
1350 assert(opr->is_register(), "visitor should only return register operands");
1351 add_def(opr, op_id, use_kind_of_output_operand(op, opr));
1352 }
1353
1354 n = visitor.opr_count(LIR_OpVisitState::tempMode);
1355 for (k = 0; k < n; k++) {
1356 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::tempMode, k);
1357 assert(opr->is_register(), "visitor should only return register operands");
1358 add_temp(opr, op_id, mustHaveRegister);
1359 }
1360
1361 // visit uses (input operands)
1362 n = visitor.opr_count(LIR_OpVisitState::inputMode);
1363 for (k = 0; k < n; k++) {
1364 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::inputMode, k);
1365 assert(opr->is_register(), "visitor should only return register operands");
1366 add_use(opr, block_from, op_id, use_kind_of_input_operand(op, opr));
1367 }
1368
1369 // Add uses of live locals from interpreter's point of view for proper
1370 // debug information generation
1371 // Treat these operands as temp values (if the life range is extended
1372 // to a call site, the value would be in a register at the call otherwise)
1373 n = visitor.info_count();
1374 for (k = 0; k < n; k++) {
1375 CodeEmitInfo* info = visitor.info_at(k);
1376 ValueStack* stack = info->stack();
1377 for_each_state_value(stack, value,
1378 add_use(value, block_from, op_id + 1, noUse);
1379 );
1380 }
1381
1382 // special steps for some instructions (especially moves)
1383 handle_method_arguments(op);
1384 handle_doubleword_moves(op);
1385 add_register_hints(op);
1386
1387 } // end of instruction iteration
1388 } // end of block iteration
1389
1390
1391 // add the range [0, 1[ to all fixed intervals
1392 // -> the register allocator need not handle unhandled fixed intervals
1393 for (int n = 0; n < LinearScan::nof_regs; n++) {
1394 Interval* interval = interval_at(n);
1395 if (interval != NULL) {
1396 interval->add_range(0, 1);
1397 }
1398 }
1399 }
1400
1401
1402 // ********** Phase 5: actual register allocation
1403
1404 int LinearScan::interval_cmp(Interval** a, Interval** b) {
1405 if (*a != NULL) {
1406 if (*b != NULL) {
1407 return (*a)->from() - (*b)->from();
1408 } else {
1409 return -1;
1410 }
1411 } else {
1412 if (*b != NULL) {
1413 return 1;
1414 } else {
1415 return 0;
1416 }
1417 }
1418 }
1419
1420 #ifndef PRODUCT
1421 bool LinearScan::is_sorted(IntervalArray* intervals) {
1422 int from = -1;
1423 int i, j;
1424 for (i = 0; i < intervals->length(); i ++) {
1425 Interval* it = intervals->at(i);
1426 if (it != NULL) {
1427 if (from > it->from()) {
1428 assert(false, "");
1429 return false;
1430 }
1431 from = it->from();
1432 }
1433 }
1434
1435 // check in both directions if sorted list and unsorted list contain same intervals
1436 for (i = 0; i < interval_count(); i++) {
1437 if (interval_at(i) != NULL) {
1438 int num_found = 0;
1439 for (j = 0; j < intervals->length(); j++) {
1440 if (interval_at(i) == intervals->at(j)) {
1441 num_found++;
1442 }
1443 }
1444 assert(num_found == 1, "lists do not contain same intervals");
1445 }
1446 }
1447 for (j = 0; j < intervals->length(); j++) {
1448 int num_found = 0;
1449 for (i = 0; i < interval_count(); i++) {
1450 if (interval_at(i) == intervals->at(j)) {
1451 num_found++;
1452 }
1453 }
1454 assert(num_found == 1, "lists do not contain same intervals");
1455 }
1456
1457 return true;
1458 }
1459 #endif
1460
1461 void LinearScan::add_to_list(Interval** first, Interval** prev, Interval* interval) {
1462 if (*prev != NULL) {
1463 (*prev)->set_next(interval);
1464 } else {
1465 *first = interval;
1466 }
1467 *prev = interval;
1468 }
1469
1470 void LinearScan::create_unhandled_lists(Interval** list1, Interval** list2, bool (is_list1)(const Interval* i), bool (is_list2)(const Interval* i)) {
1471 assert(is_sorted(_sorted_intervals), "interval list is not sorted");
1472
1473 *list1 = *list2 = Interval::end();
1474
1475 Interval* list1_prev = NULL;
1476 Interval* list2_prev = NULL;
1477 Interval* v;
1478
1479 const int n = _sorted_intervals->length();
1480 for (int i = 0; i < n; i++) {
1481 v = _sorted_intervals->at(i);
1482 if (v == NULL) continue;
1483
1484 if (is_list1(v)) {
1485 add_to_list(list1, &list1_prev, v);
1486 } else if (is_list2 == NULL || is_list2(v)) {
1487 add_to_list(list2, &list2_prev, v);
1488 }
1489 }
1490
1491 if (list1_prev != NULL) list1_prev->set_next(Interval::end());
1492 if (list2_prev != NULL) list2_prev->set_next(Interval::end());
1493
1494 assert(list1_prev == NULL || list1_prev->next() == Interval::end(), "linear list ends not with sentinel");
1495 assert(list2_prev == NULL || list2_prev->next() == Interval::end(), "linear list ends not with sentinel");
1496 }
1497
1498
1499 void LinearScan::sort_intervals_before_allocation() {
1500 TIME_LINEAR_SCAN(timer_sort_intervals_before);
1501
1502 IntervalList* unsorted_list = &_intervals;
1503 int unsorted_len = unsorted_list->length();
1504 int sorted_len = 0;
1505 int unsorted_idx;
1506 int sorted_idx = 0;
1507 int sorted_from_max = -1;
1508
1509 // calc number of items for sorted list (sorted list must not contain NULL values)
1510 for (unsorted_idx = 0; unsorted_idx < unsorted_len; unsorted_idx++) {
1511 if (unsorted_list->at(unsorted_idx) != NULL) {
1512 sorted_len++;
1513 }
1514 }
1515 IntervalArray* sorted_list = new IntervalArray(sorted_len);
1516
1517 // special sorting algorithm: the original interval-list is almost sorted,
1518 // only some intervals are swapped. So this is much faster than a complete QuickSort
1519 for (unsorted_idx = 0; unsorted_idx < unsorted_len; unsorted_idx++) {
1520 Interval* cur_interval = unsorted_list->at(unsorted_idx);
1521
1522 if (cur_interval != NULL) {
1523 int cur_from = cur_interval->from();
1524
1525 if (sorted_from_max <= cur_from) {
1526 sorted_list->at_put(sorted_idx++, cur_interval);
1527 sorted_from_max = cur_interval->from();
1528 } else {
1529 // the asumption that the intervals are already sorted failed,
1530 // so this interval must be sorted in manually
1531 int j;
1532 for (j = sorted_idx - 1; j >= 0 && cur_from < sorted_list->at(j)->from(); j--) {
1533 sorted_list->at_put(j + 1, sorted_list->at(j));
1534 }
1535 sorted_list->at_put(j + 1, cur_interval);
1536 sorted_idx++;
1537 }
1538 }
1539 }
1540 _sorted_intervals = sorted_list;
1541 }
1542
1543 void LinearScan::sort_intervals_after_allocation() {
1544 TIME_LINEAR_SCAN(timer_sort_intervals_after);
1545
1546 IntervalArray* old_list = _sorted_intervals;
1547 IntervalList* new_list = _new_intervals_from_allocation;
1548 int old_len = old_list->length();
1549 int new_len = new_list->length();
1550
1551 if (new_len == 0) {
1552 // no intervals have been added during allocation, so sorted list is already up to date
1553 return;
1554 }
1555
1556 // conventional sort-algorithm for new intervals
1557 new_list->sort(interval_cmp);
1558
1559 // merge old and new list (both already sorted) into one combined list
1560 IntervalArray* combined_list = new IntervalArray(old_len + new_len);
1561 int old_idx = 0;
1562 int new_idx = 0;
1563
1564 while (old_idx + new_idx < old_len + new_len) {
1565 if (new_idx >= new_len || (old_idx < old_len && old_list->at(old_idx)->from() <= new_list->at(new_idx)->from())) {
1566 combined_list->at_put(old_idx + new_idx, old_list->at(old_idx));
1567 old_idx++;
1568 } else {
1569 combined_list->at_put(old_idx + new_idx, new_list->at(new_idx));
1570 new_idx++;
1571 }
1572 }
1573
1574 _sorted_intervals = combined_list;
1575 }
1576
1577
1578 void LinearScan::allocate_registers() {
1579 TIME_LINEAR_SCAN(timer_allocate_registers);
1580
1581 Interval* precolored_cpu_intervals, *not_precolored_cpu_intervals;
1582 Interval* precolored_fpu_intervals, *not_precolored_fpu_intervals;
1583
1584 create_unhandled_lists(&precolored_cpu_intervals, ¬_precolored_cpu_intervals, is_precolored_cpu_interval, is_virtual_cpu_interval);
1585 if (has_fpu_registers()) {
1586 create_unhandled_lists(&precolored_fpu_intervals, ¬_precolored_fpu_intervals, is_precolored_fpu_interval, is_virtual_fpu_interval);
1587 #ifdef ASSERT
1588 } else {
1589 // fpu register allocation is omitted because no virtual fpu registers are present
1590 // just check this again...
1591 create_unhandled_lists(&precolored_fpu_intervals, ¬_precolored_fpu_intervals, is_precolored_fpu_interval, is_virtual_fpu_interval);
1592 assert(not_precolored_fpu_intervals == Interval::end(), "missed an uncolored fpu interval");
1593 #endif
1594 }
1595
1596 // allocate cpu registers
1597 LinearScanWalker cpu_lsw(this, precolored_cpu_intervals, not_precolored_cpu_intervals);
1598 cpu_lsw.walk();
1599 cpu_lsw.finish_allocation();
1600
1601 if (has_fpu_registers()) {
1602 // allocate fpu registers
1603 LinearScanWalker fpu_lsw(this, precolored_fpu_intervals, not_precolored_fpu_intervals);
1604 fpu_lsw.walk();
1605 fpu_lsw.finish_allocation();
1606 }
1607 }
1608
1609
1610 // ********** Phase 6: resolve data flow
1611 // (insert moves at edges between blocks if intervals have been split)
1612
1613 // wrapper for Interval::split_child_at_op_id that performs a bailout in product mode
1614 // instead of returning NULL
1615 Interval* LinearScan::split_child_at_op_id(Interval* interval, int op_id, LIR_OpVisitState::OprMode mode) {
1616 Interval* result = interval->split_child_at_op_id(op_id, mode);
1617 if (result != NULL) {
1618 return result;
1619 }
1620
1621 assert(false, "must find an interval, but do a clean bailout in product mode");
1622 result = new Interval(LIR_OprDesc::vreg_base);
1623 result->assign_reg(0);
1624 result->set_type(T_INT);
1625 BAILOUT_("LinearScan: interval is NULL", result);
1626 }
1627
1628
1629 Interval* LinearScan::interval_at_block_begin(BlockBegin* block, int reg_num) {
1630 assert(LinearScan::nof_regs <= reg_num && reg_num < num_virtual_regs(), "register number out of bounds");
1631 assert(interval_at(reg_num) != NULL, "no interval found");
1632
1633 return split_child_at_op_id(interval_at(reg_num), block->first_lir_instruction_id(), LIR_OpVisitState::outputMode);
1634 }
1635
1636 Interval* LinearScan::interval_at_block_end(BlockBegin* block, int reg_num) {
1637 assert(LinearScan::nof_regs <= reg_num && reg_num < num_virtual_regs(), "register number out of bounds");
1638 assert(interval_at(reg_num) != NULL, "no interval found");
1639
1640 return split_child_at_op_id(interval_at(reg_num), block->last_lir_instruction_id() + 1, LIR_OpVisitState::outputMode);
1641 }
1642
1643 Interval* LinearScan::interval_at_op_id(int reg_num, int op_id) {
1644 assert(LinearScan::nof_regs <= reg_num && reg_num < num_virtual_regs(), "register number out of bounds");
1645 assert(interval_at(reg_num) != NULL, "no interval found");
1646
1647 return split_child_at_op_id(interval_at(reg_num), op_id, LIR_OpVisitState::inputMode);
1648 }
1649
1650
1651 void LinearScan::resolve_collect_mappings(BlockBegin* from_block, BlockBegin* to_block, MoveResolver &move_resolver) {
1652 DEBUG_ONLY(move_resolver.check_empty());
1653
1654 const int num_regs = num_virtual_regs();
1655 const int size = live_set_size();
1656 const BitMap live_at_edge = to_block->live_in();
1657
1658 // visit all registers where the live_at_edge bit is set
1659 for (int r = (int)live_at_edge.get_next_one_offset(0, size); r < size; r = (int)live_at_edge.get_next_one_offset(r + 1, size)) {
1660 assert(r < num_regs, "live information set for not exisiting interval");
1661 assert(from_block->live_out().at(r) && to_block->live_in().at(r), "interval not live at this edge");
1662
1663 Interval* from_interval = interval_at_block_end(from_block, r);
1664 Interval* to_interval = interval_at_block_begin(to_block, r);
1665
1666 if (from_interval != to_interval && (from_interval->assigned_reg() != to_interval->assigned_reg() || from_interval->assigned_regHi() != to_interval->assigned_regHi())) {
1667 // need to insert move instruction
1668 move_resolver.add_mapping(from_interval, to_interval);
1669 }
1670 }
1671 }
1672
1673
1674 void LinearScan::resolve_find_insert_pos(BlockBegin* from_block, BlockBegin* to_block, MoveResolver &move_resolver) {
1675 if (from_block->number_of_sux() <= 1) {
1676 TRACE_LINEAR_SCAN(4, tty->print_cr("inserting moves at end of from_block B%d", from_block->block_id()));
1677
1678 LIR_OpList* instructions = from_block->lir()->instructions_list();
1679 LIR_OpBranch* branch = instructions->last()->as_OpBranch();
1680 if (branch != NULL) {
1681 // insert moves before branch
1682 assert(branch->cond() == lir_cond_always, "block does not end with an unconditional jump");
1683 move_resolver.set_insert_position(from_block->lir(), instructions->length() - 2);
1684 } else {
1685 move_resolver.set_insert_position(from_block->lir(), instructions->length() - 1);
1686 }
1687
1688 } else {
1689 TRACE_LINEAR_SCAN(4, tty->print_cr("inserting moves at beginning of to_block B%d", to_block->block_id()));
1690 #ifdef ASSERT
1691 assert(from_block->lir()->instructions_list()->at(0)->as_OpLabel() != NULL, "block does not start with a label");
1692
1693 // because the number of predecessor edges matches the number of
1694 // successor edges, blocks which are reached by switch statements
1695 // may have be more than one predecessor but it will be guaranteed
1696 // that all predecessors will be the same.
1697 for (int i = 0; i < to_block->number_of_preds(); i++) {
1698 assert(from_block == to_block->pred_at(i), "all critical edges must be broken");
1699 }
1700 #endif
1701
1702 move_resolver.set_insert_position(to_block->lir(), 0);
1703 }
1704 }
1705
1706
1707 // insert necessary moves (spilling or reloading) at edges between blocks if interval has been split
1708 void LinearScan::resolve_data_flow() {
1709 TIME_LINEAR_SCAN(timer_resolve_data_flow);
1710
1711 int num_blocks = block_count();
1712 MoveResolver move_resolver(this);
1713 BitMap block_completed(num_blocks); block_completed.clear();
1714 BitMap already_resolved(num_blocks); already_resolved.clear();
1715
1716 int i;
1717 for (i = 0; i < num_blocks; i++) {
1718 BlockBegin* block = block_at(i);
1719
1720 // check if block has only one predecessor and only one successor
1721 if (block->number_of_preds() == 1 && block->number_of_sux() == 1 && block->number_of_exception_handlers() == 0) {
1722 LIR_OpList* instructions = block->lir()->instructions_list();
1723 assert(instructions->at(0)->code() == lir_label, "block must start with label");
1724 assert(instructions->last()->code() == lir_branch, "block with successors must end with branch");
1725 assert(instructions->last()->as_OpBranch()->cond() == lir_cond_always, "block with successor must end with unconditional branch");
1726
1727 // check if block is empty (only label and branch)
1728 if (instructions->length() == 2) {
1729 BlockBegin* pred = block->pred_at(0);
1730 BlockBegin* sux = block->sux_at(0);
1731
1732 // prevent optimization of two consecutive blocks
1733 if (!block_completed.at(pred->linear_scan_number()) && !block_completed.at(sux->linear_scan_number())) {
1734 TRACE_LINEAR_SCAN(3, tty->print_cr("**** optimizing empty block B%d (pred: B%d, sux: B%d)", block->block_id(), pred->block_id(), sux->block_id()));
1735 block_completed.set_bit(block->linear_scan_number());
1736
1737 // directly resolve between pred and sux (without looking at the empty block between)
1738 resolve_collect_mappings(pred, sux, move_resolver);
1739 if (move_resolver.has_mappings()) {
1740 move_resolver.set_insert_position(block->lir(), 0);
1741 move_resolver.resolve_and_append_moves();
1742 }
1743 }
1744 }
1745 }
1746 }
1747
1748
1749 for (i = 0; i < num_blocks; i++) {
1750 if (!block_completed.at(i)) {
1751 BlockBegin* from_block = block_at(i);
1752 already_resolved.set_from(block_completed);
1753
1754 int num_sux = from_block->number_of_sux();
1755 for (int s = 0; s < num_sux; s++) {
1756 BlockBegin* to_block = from_block->sux_at(s);
1757
1758 // check for duplicate edges between the same blocks (can happen with switch blocks)
1759 if (!already_resolved.at(to_block->linear_scan_number())) {
1760 TRACE_LINEAR_SCAN(3, tty->print_cr("**** processing edge between B%d and B%d", from_block->block_id(), to_block->block_id()));
1761 already_resolved.set_bit(to_block->linear_scan_number());
1762
1763 // collect all intervals that have been split between from_block and to_block
1764 resolve_collect_mappings(from_block, to_block, move_resolver);
1765 if (move_resolver.has_mappings()) {
1766 resolve_find_insert_pos(from_block, to_block, move_resolver);
1767 move_resolver.resolve_and_append_moves();
1768 }
1769 }
1770 }
1771 }
1772 }
1773 }
1774
1775
1776 void LinearScan::resolve_exception_entry(BlockBegin* block, int reg_num, MoveResolver &move_resolver) {
1777 if (interval_at(reg_num) == NULL) {
1778 // if a phi function is never used, no interval is created -> ignore this
1779 return;
1780 }
1781
1782 Interval* interval = interval_at_block_begin(block, reg_num);
1783 int reg = interval->assigned_reg();
1784 int regHi = interval->assigned_regHi();
1785
1786 if ((reg < nof_regs && interval->always_in_memory()) ||
1787 (use_fpu_stack_allocation() && reg >= pd_first_fpu_reg && reg <= pd_last_fpu_reg)) {
1788 // the interval is split to get a short range that is located on the stack
1789 // in the following two cases:
1790 // * the interval started in memory (e.g. method parameter), but is currently in a register
1791 // this is an optimization for exception handling that reduces the number of moves that
1792 // are necessary for resolving the states when an exception uses this exception handler
1793 // * the interval would be on the fpu stack at the begin of the exception handler
1794 // this is not allowed because of the complicated fpu stack handling on Intel
1795
1796 // range that will be spilled to memory
1797 int from_op_id = block->first_lir_instruction_id();
1798 int to_op_id = from_op_id + 1; // short live range of length 1
1799 assert(interval->from() <= from_op_id && interval->to() >= to_op_id,
1800 "no split allowed between exception entry and first instruction");
1801
1802 if (interval->from() != from_op_id) {
1803 // the part before from_op_id is unchanged
1804 interval = interval->split(from_op_id);
1805 interval->assign_reg(reg, regHi);
1806 append_interval(interval);
1807 }
1808 assert(interval->from() == from_op_id, "must be true now");
1809
1810 Interval* spilled_part = interval;
1811 if (interval->to() != to_op_id) {
1812 // the part after to_op_id is unchanged
1813 spilled_part = interval->split_from_start(to_op_id);
1814 append_interval(spilled_part);
1815 move_resolver.add_mapping(spilled_part, interval);
1816 }
1817 assign_spill_slot(spilled_part);
1818
1819 assert(spilled_part->from() == from_op_id && spilled_part->to() == to_op_id, "just checking");
1820 }
1821 }
1822
1823 void LinearScan::resolve_exception_entry(BlockBegin* block, MoveResolver &move_resolver) {
1824 assert(block->is_set(BlockBegin::exception_entry_flag), "should not call otherwise");
1825 DEBUG_ONLY(move_resolver.check_empty());
1826
1827 // visit all registers where the live_in bit is set
1828 int size = live_set_size();
1829 for (int r = (int)block->live_in().get_next_one_offset(0, size); r < size; r = (int)block->live_in().get_next_one_offset(r + 1, size)) {
1830 resolve_exception_entry(block, r, move_resolver);
1831 }
1832
1833 // the live_in bits are not set for phi functions of the xhandler entry, so iterate them separately
1834 for_each_phi_fun(block, phi,
1835 resolve_exception_entry(block, phi->operand()->vreg_number(), move_resolver)
1836 );
1837
1838 if (move_resolver.has_mappings()) {
1839 // insert moves after first instruction
1840 move_resolver.set_insert_position(block->lir(), 1);
1841 move_resolver.resolve_and_append_moves();
1842 }
1843 }
1844
1845
1846 void LinearScan::resolve_exception_edge(XHandler* handler, int throwing_op_id, int reg_num, Phi* phi, MoveResolver &move_resolver) {
1847 if (interval_at(reg_num) == NULL) {
1848 // if a phi function is never used, no interval is created -> ignore this
1849 return;
1850 }
1851
1852 // the computation of to_interval is equal to resolve_collect_mappings,
1853 // but from_interval is more complicated because of phi functions
1854 BlockBegin* to_block = handler->entry_block();
1855 Interval* to_interval = interval_at_block_begin(to_block, reg_num);
1856
1857 if (phi != NULL) {
1858 // phi function of the exception entry block
1859 // no moves are created for this phi function in the LIR_Generator, so the
1860 // interval at the throwing instruction must be searched using the operands
1861 // of the phi function
1862 Value from_value = phi->operand_at(handler->phi_operand());
1863
1864 // with phi functions it can happen that the same from_value is used in
1865 // multiple mappings, so notify move-resolver that this is allowed
1866 move_resolver.set_multiple_reads_allowed();
1867
1868 Constant* con = from_value->as_Constant();
1869 if (con != NULL && !con->is_pinned()) {
1870 // unpinned constants may have no register, so add mapping from constant to interval
1871 move_resolver.add_mapping(LIR_OprFact::value_type(con->type()), to_interval);
1872 } else {
1873 // search split child at the throwing op_id
1874 Interval* from_interval = interval_at_op_id(from_value->operand()->vreg_number(), throwing_op_id);
1875 move_resolver.add_mapping(from_interval, to_interval);
1876 }
1877
1878 } else {
1879 // no phi function, so use reg_num also for from_interval
1880 // search split child at the throwing op_id
1881 Interval* from_interval = interval_at_op_id(reg_num, throwing_op_id);
1882 if (from_interval != to_interval) {
1883 // optimization to reduce number of moves: when to_interval is on stack and
1884 // the stack slot is known to be always correct, then no move is necessary
1885 if (!from_interval->always_in_memory() || from_interval->canonical_spill_slot() != to_interval->assigned_reg()) {
1886 move_resolver.add_mapping(from_interval, to_interval);
1887 }
1888 }
1889 }
1890 }
1891
1892 void LinearScan::resolve_exception_edge(XHandler* handler, int throwing_op_id, MoveResolver &move_resolver) {
1893 TRACE_LINEAR_SCAN(4, tty->print_cr("resolving exception handler B%d: throwing_op_id=%d", handler->entry_block()->block_id(), throwing_op_id));
1894
1895 DEBUG_ONLY(move_resolver.check_empty());
1896 assert(handler->lir_op_id() == -1, "already processed this xhandler");
1897 DEBUG_ONLY(handler->set_lir_op_id(throwing_op_id));
1898 assert(handler->entry_code() == NULL, "code already present");
1899
1900 // visit all registers where the live_in bit is set
1901 BlockBegin* block = handler->entry_block();
1902 int size = live_set_size();
1903 for (int r = (int)block->live_in().get_next_one_offset(0, size); r < size; r = (int)block->live_in().get_next_one_offset(r + 1, size)) {
1904 resolve_exception_edge(handler, throwing_op_id, r, NULL, move_resolver);
1905 }
1906
1907 // the live_in bits are not set for phi functions of the xhandler entry, so iterate them separately
1908 for_each_phi_fun(block, phi,
1909 resolve_exception_edge(handler, throwing_op_id, phi->operand()->vreg_number(), phi, move_resolver)
1910 );
1911
1912 if (move_resolver.has_mappings()) {
1913 LIR_List* entry_code = new LIR_List(compilation());
1914 move_resolver.set_insert_position(entry_code, 0);
1915 move_resolver.resolve_and_append_moves();
1916
1917 entry_code->jump(handler->entry_block());
1918 handler->set_entry_code(entry_code);
1919 }
1920 }
1921
1922
1923 void LinearScan::resolve_exception_handlers() {
1924 MoveResolver move_resolver(this);
1925 LIR_OpVisitState visitor;
1926 int num_blocks = block_count();
1927
1928 int i;
1929 for (i = 0; i < num_blocks; i++) {
1930 BlockBegin* block = block_at(i);
1931 if (block->is_set(BlockBegin::exception_entry_flag)) {
1932 resolve_exception_entry(block, move_resolver);
1933 }
1934 }
1935
1936 for (i = 0; i < num_blocks; i++) {
1937 BlockBegin* block = block_at(i);
1938 LIR_List* ops = block->lir();
1939 int num_ops = ops->length();
1940
1941 // iterate all instructions of the block. skip the first because it is always a label
1942 assert(visitor.no_operands(ops->at(0)), "first operation must always be a label");
1943 for (int j = 1; j < num_ops; j++) {
1944 LIR_Op* op = ops->at(j);
1945 int op_id = op->id();
1946
1947 if (op_id != -1 && has_info(op_id)) {
1948 // visit operation to collect all operands
1949 visitor.visit(op);
1950 assert(visitor.info_count() > 0, "should not visit otherwise");
1951
1952 XHandlers* xhandlers = visitor.all_xhandler();
1953 int n = xhandlers->length();
1954 for (int k = 0; k < n; k++) {
1955 resolve_exception_edge(xhandlers->handler_at(k), op_id, move_resolver);
1956 }
1957
1958 #ifdef ASSERT
1959 } else {
1960 visitor.visit(op);
1961 assert(visitor.all_xhandler()->length() == 0, "missed exception handler");
1962 #endif
1963 }
1964 }
1965 }
1966 }
1967
1968
1969 // ********** Phase 7: assign register numbers back to LIR
1970 // (includes computation of debug information and oop maps)
1971
1972 VMReg LinearScan::vm_reg_for_interval(Interval* interval) {
1973 VMReg reg = interval->cached_vm_reg();
1974 if (!reg->is_valid() ) {
1975 reg = vm_reg_for_operand(operand_for_interval(interval));
1976 interval->set_cached_vm_reg(reg);
1977 }
1978 assert(reg == vm_reg_for_operand(operand_for_interval(interval)), "wrong cached value");
1979 return reg;
1980 }
1981
1982 VMReg LinearScan::vm_reg_for_operand(LIR_Opr opr) {
1983 assert(opr->is_oop(), "currently only implemented for oop operands");
1984 return frame_map()->regname(opr);
1985 }
1986
1987
1988 LIR_Opr LinearScan::operand_for_interval(Interval* interval) {
1989 LIR_Opr opr = interval->cached_opr();
1990 if (opr->is_illegal()) {
1991 opr = calc_operand_for_interval(interval);
1992 interval->set_cached_opr(opr);
1993 }
1994
1995 assert(opr == calc_operand_for_interval(interval), "wrong cached value");
1996 return opr;
1997 }
1998
1999 LIR_Opr LinearScan::calc_operand_for_interval(const Interval* interval) {
2000 int assigned_reg = interval->assigned_reg();
2001 BasicType type = interval->type();
2002
2003 if (assigned_reg >= nof_regs) {
2004 // stack slot
2005 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2006 return LIR_OprFact::stack(assigned_reg - nof_regs, type);
2007
2008 } else {
2009 // register
2010 switch (type) {
2011 case T_OBJECT: {
2012 assert(assigned_reg >= pd_first_cpu_reg && assigned_reg <= pd_last_cpu_reg, "no cpu register");
2013 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2014 return LIR_OprFact::single_cpu_oop(assigned_reg);
2015 }
2016
2017 case T_INT: {
2018 assert(assigned_reg >= pd_first_cpu_reg && assigned_reg <= pd_last_cpu_reg, "no cpu register");
2019 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2020 return LIR_OprFact::single_cpu(assigned_reg);
2021 }
2022
2023 case T_LONG: {
2024 int assigned_regHi = interval->assigned_regHi();
2025 assert(assigned_reg >= pd_first_cpu_reg && assigned_reg <= pd_last_cpu_reg, "no cpu register");
2026 assert(num_physical_regs(T_LONG) == 1 ||
2027 (assigned_regHi >= pd_first_cpu_reg && assigned_regHi <= pd_last_cpu_reg), "no cpu register");
2028
2029 assert(assigned_reg != assigned_regHi, "invalid allocation");
2030 assert(num_physical_regs(T_LONG) == 1 || assigned_reg < assigned_regHi,
2031 "register numbers must be sorted (ensure that e.g. a move from eax,ebx to ebx,eax can not occur)");
2032 assert((assigned_regHi != any_reg) ^ (num_physical_regs(T_LONG) == 1), "must be match");
2033 if (requires_adjacent_regs(T_LONG)) {
2034 assert(assigned_reg % 2 == 0 && assigned_reg + 1 == assigned_regHi, "must be sequential and even");
2035 }
2036
2037 #ifdef _LP64
2038 return LIR_OprFact::double_cpu(assigned_reg, assigned_reg);
2039 #else
2040 #ifdef SPARC
2041 return LIR_OprFact::double_cpu(assigned_regHi, assigned_reg);
2042 #else
2043 return LIR_OprFact::double_cpu(assigned_reg, assigned_regHi);
2044 #endif // SPARC
2045 #endif // LP64
2046 }
2047
2048 case T_FLOAT: {
2049 #ifdef X86
2050 if (UseSSE >= 1) {
2051 assert(assigned_reg >= pd_first_xmm_reg && assigned_reg <= pd_last_xmm_reg, "no xmm register");
2052 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2053 return LIR_OprFact::single_xmm(assigned_reg - pd_first_xmm_reg);
2054 }
2055 #endif
2056
2057 assert(assigned_reg >= pd_first_fpu_reg && assigned_reg <= pd_last_fpu_reg, "no fpu register");
2058 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2059 return LIR_OprFact::single_fpu(assigned_reg - pd_first_fpu_reg);
2060 }
2061
2062 case T_DOUBLE: {
2063 #ifdef X86
2064 if (UseSSE >= 2) {
2065 assert(assigned_reg >= pd_first_xmm_reg && assigned_reg <= pd_last_xmm_reg, "no xmm register");
2066 assert(interval->assigned_regHi() == any_reg, "must not have hi register (double xmm values are stored in one register)");
2067 return LIR_OprFact::double_xmm(assigned_reg - pd_first_xmm_reg);
2068 }
2069 #endif
2070
2071 #ifdef SPARC
2072 assert(assigned_reg >= pd_first_fpu_reg && assigned_reg <= pd_last_fpu_reg, "no fpu register");
2073 assert(interval->assigned_regHi() >= pd_first_fpu_reg && interval->assigned_regHi() <= pd_last_fpu_reg, "no fpu register");
2074 assert(assigned_reg % 2 == 0 && assigned_reg + 1 == interval->assigned_regHi(), "must be sequential and even");
2075 LIR_Opr result = LIR_OprFact::double_fpu(interval->assigned_regHi() - pd_first_fpu_reg, assigned_reg - pd_first_fpu_reg);
2076 #else
2077 assert(assigned_reg >= pd_first_fpu_reg && assigned_reg <= pd_last_fpu_reg, "no fpu register");
2078 assert(interval->assigned_regHi() == any_reg, "must not have hi register (double fpu values are stored in one register on Intel)");
2079 LIR_Opr result = LIR_OprFact::double_fpu(assigned_reg - pd_first_fpu_reg);
2080 #endif
2081 return result;
2082 }
2083
2084 default: {
2085 ShouldNotReachHere();
2086 return LIR_OprFact::illegalOpr;
2087 }
2088 }
2089 }
2090 }
2091
2092 LIR_Opr LinearScan::canonical_spill_opr(Interval* interval) {
2093 assert(interval->canonical_spill_slot() >= nof_regs, "canonical spill slot not set");
2094 return LIR_OprFact::stack(interval->canonical_spill_slot() - nof_regs, interval->type());
2095 }
2096
2097 LIR_Opr LinearScan::color_lir_opr(LIR_Opr opr, int op_id, LIR_OpVisitState::OprMode mode) {
2098 assert(opr->is_virtual(), "should not call this otherwise");
2099
2100 Interval* interval = interval_at(opr->vreg_number());
2101 assert(interval != NULL, "interval must exist");
2102
2103 if (op_id != -1) {
2104 #ifdef ASSERT
2105 BlockBegin* block = block_of_op_with_id(op_id);
2106 if (block->number_of_sux() <= 1 && op_id == block->last_lir_instruction_id()) {
2107 // check if spill moves could have been appended at the end of this block, but
2108 // before the branch instruction. So the split child information for this branch would
2109 // be incorrect.
2110 LIR_OpBranch* branch = block->lir()->instructions_list()->last()->as_OpBranch();
2111 if (branch != NULL) {
2112 if (block->live_out().at(opr->vreg_number())) {
2113 assert(branch->cond() == lir_cond_always, "block does not end with an unconditional jump");
2114 assert(false, "can't get split child for the last branch of a block because the information would be incorrect (moves are inserted before the branch in resolve_data_flow)");
2115 }
2116 }
2117 }
2118 #endif
2119
2120 // operands are not changed when an interval is split during allocation,
2121 // so search the right interval here
2122 interval = split_child_at_op_id(interval, op_id, mode);
2123 }
2124
2125 LIR_Opr res = operand_for_interval(interval);
2126
2127 #ifdef X86
2128 // new semantic for is_last_use: not only set on definite end of interval,
2129 // but also before hole
2130 // This may still miss some cases (e.g. for dead values), but it is not necessary that the
2131 // last use information is completely correct
2132 // information is only needed for fpu stack allocation
2133 if (res->is_fpu_register()) {
2134 if (opr->is_last_use() || op_id == interval->to() || (op_id != -1 && interval->has_hole_between(op_id, op_id + 1))) {
2135 assert(op_id == -1 || !is_block_begin(op_id), "holes at begin of block may also result from control flow");
2136 res = res->make_last_use();
2137 }
2138 }
2139 #endif
2140
2141 assert(!gen()->is_vreg_flag_set(opr->vreg_number(), LIRGenerator::callee_saved) || !FrameMap::is_caller_save_register(res), "bad allocation");
2142
2143 return res;
2144 }
2145
2146
2147 #ifdef ASSERT
2148 // some methods used to check correctness of debug information
2149
2150 void assert_no_register_values(GrowableArray<ScopeValue*>* values) {
2151 if (values == NULL) {
2152 return;
2153 }
2154
2155 for (int i = 0; i < values->length(); i++) {
2156 ScopeValue* value = values->at(i);
2157
2158 if (value->is_location()) {
2159 Location location = ((LocationValue*)value)->location();
2160 assert(location.where() == Location::on_stack, "value is in register");
2161 }
2162 }
2163 }
2164
2165 void assert_no_register_values(GrowableArray<MonitorValue*>* values) {
2166 if (values == NULL) {
2167 return;
2168 }
2169
2170 for (int i = 0; i < values->length(); i++) {
2171 MonitorValue* value = values->at(i);
2172
2173 if (value->owner()->is_location()) {
2174 Location location = ((LocationValue*)value->owner())->location();
2175 assert(location.where() == Location::on_stack, "owner is in register");
2176 }
2177 assert(value->basic_lock().where() == Location::on_stack, "basic_lock is in register");
2178 }
2179 }
2180
2181 void assert_equal(Location l1, Location l2) {
2182 assert(l1.where() == l2.where() && l1.type() == l2.type() && l1.offset() == l2.offset(), "");
2183 }
2184
2185 void assert_equal(ScopeValue* v1, ScopeValue* v2) {
2186 if (v1->is_location()) {
2187 assert(v2->is_location(), "");
2188 assert_equal(((LocationValue*)v1)->location(), ((LocationValue*)v2)->location());
2189 } else if (v1->is_constant_int()) {
2190 assert(v2->is_constant_int(), "");
2191 assert(((ConstantIntValue*)v1)->value() == ((ConstantIntValue*)v2)->value(), "");
2192 } else if (v1->is_constant_double()) {
2193 assert(v2->is_constant_double(), "");
2194 assert(((ConstantDoubleValue*)v1)->value() == ((ConstantDoubleValue*)v2)->value(), "");
2195 } else if (v1->is_constant_long()) {
2196 assert(v2->is_constant_long(), "");
2197 assert(((ConstantLongValue*)v1)->value() == ((ConstantLongValue*)v2)->value(), "");
2198 } else if (v1->is_constant_oop()) {
2199 assert(v2->is_constant_oop(), "");
2200 assert(((ConstantOopWriteValue*)v1)->value() == ((ConstantOopWriteValue*)v2)->value(), "");
2201 } else {
2202 ShouldNotReachHere();
2203 }
2204 }
2205
2206 void assert_equal(MonitorValue* m1, MonitorValue* m2) {
2207 assert_equal(m1->owner(), m2->owner());
2208 assert_equal(m1->basic_lock(), m2->basic_lock());
2209 }
2210
2211 void assert_equal(IRScopeDebugInfo* d1, IRScopeDebugInfo* d2) {
2212 assert(d1->scope() == d2->scope(), "not equal");
2213 assert(d1->bci() == d2->bci(), "not equal");
2214
2215 if (d1->locals() != NULL) {
2216 assert(d1->locals() != NULL && d2->locals() != NULL, "not equal");
2217 assert(d1->locals()->length() == d2->locals()->length(), "not equal");
2218 for (int i = 0; i < d1->locals()->length(); i++) {
2219 assert_equal(d1->locals()->at(i), d2->locals()->at(i));
2220 }
2221 } else {
2222 assert(d1->locals() == NULL && d2->locals() == NULL, "not equal");
2223 }
2224
2225 if (d1->expressions() != NULL) {
2226 assert(d1->expressions() != NULL && d2->expressions() != NULL, "not equal");
2227 assert(d1->expressions()->length() == d2->expressions()->length(), "not equal");
2228 for (int i = 0; i < d1->expressions()->length(); i++) {
2229 assert_equal(d1->expressions()->at(i), d2->expressions()->at(i));
2230 }
2231 } else {
2232 assert(d1->expressions() == NULL && d2->expressions() == NULL, "not equal");
2233 }
2234
2235 if (d1->monitors() != NULL) {
2236 assert(d1->monitors() != NULL && d2->monitors() != NULL, "not equal");
2237 assert(d1->monitors()->length() == d2->monitors()->length(), "not equal");
2238 for (int i = 0; i < d1->monitors()->length(); i++) {
2239 assert_equal(d1->monitors()->at(i), d2->monitors()->at(i));
2240 }
2241 } else {
2242 assert(d1->monitors() == NULL && d2->monitors() == NULL, "not equal");
2243 }
2244
2245 if (d1->caller() != NULL) {
2246 assert(d1->caller() != NULL && d2->caller() != NULL, "not equal");
2247 assert_equal(d1->caller(), d2->caller());
2248 } else {
2249 assert(d1->caller() == NULL && d2->caller() == NULL, "not equal");
2250 }
2251 }
2252
2253 void check_stack_depth(CodeEmitInfo* info, int stack_end) {
2254 if (info->bci() != SynchronizationEntryBCI && !info->scope()->method()->is_native()) {
2255 Bytecodes::Code code = info->scope()->method()->java_code_at_bci(info->bci());
2256 switch (code) {
2257 case Bytecodes::_ifnull : // fall through
2258 case Bytecodes::_ifnonnull : // fall through
2259 case Bytecodes::_ifeq : // fall through
2260 case Bytecodes::_ifne : // fall through
2261 case Bytecodes::_iflt : // fall through
2262 case Bytecodes::_ifge : // fall through
2263 case Bytecodes::_ifgt : // fall through
2264 case Bytecodes::_ifle : // fall through
2265 case Bytecodes::_if_icmpeq : // fall through
2266 case Bytecodes::_if_icmpne : // fall through
2267 case Bytecodes::_if_icmplt : // fall through
2268 case Bytecodes::_if_icmpge : // fall through
2269 case Bytecodes::_if_icmpgt : // fall through
2270 case Bytecodes::_if_icmple : // fall through
2271 case Bytecodes::_if_acmpeq : // fall through
2272 case Bytecodes::_if_acmpne :
2273 assert(stack_end >= -Bytecodes::depth(code), "must have non-empty expression stack at if bytecode");
2274 break;
2275 }
2276 }
2277 }
2278
2279 #endif // ASSERT
2280
2281
2282 IntervalWalker* LinearScan::init_compute_oop_maps() {
2283 // setup lists of potential oops for walking
2284 Interval* oop_intervals;
2285 Interval* non_oop_intervals;
2286
2287 create_unhandled_lists(&oop_intervals, &non_oop_intervals, is_oop_interval, NULL);
2288
2289 // intervals that have no oops inside need not to be processed
2290 // to ensure a walking until the last instruction id, add a dummy interval
2291 // with a high operation id
2292 non_oop_intervals = new Interval(any_reg);
2293 non_oop_intervals->add_range(max_jint - 2, max_jint - 1);
2294
2295 return new IntervalWalker(this, oop_intervals, non_oop_intervals);
2296 }
2297
2298
2299 OopMap* LinearScan::compute_oop_map(IntervalWalker* iw, LIR_Op* op, CodeEmitInfo* info, bool is_call_site) {
2300 TRACE_LINEAR_SCAN(3, tty->print_cr("creating oop map at op_id %d", op->id()));
2301
2302 // walk before the current operation -> intervals that start at
2303 // the operation (= output operands of the operation) are not
2304 // included in the oop map
2305 iw->walk_before(op->id());
2306
2307 int frame_size = frame_map()->framesize();
2308 int arg_count = frame_map()->oop_map_arg_count();
2309 OopMap* map = new OopMap(frame_size, arg_count);
2310
2311 // Check if this is a patch site.
2312 bool is_patch_info = false;
2313 if (op->code() == lir_move) {
2314 assert(!is_call_site, "move must not be a call site");
2315 assert(op->as_Op1() != NULL, "move must be LIR_Op1");
2316 LIR_Op1* move = (LIR_Op1*)op;
2317
2318 is_patch_info = move->patch_code() != lir_patch_none;
2319 }
2320
2321 // Iterate through active intervals
2322 for (Interval* interval = iw->active_first(fixedKind); interval != Interval::end(); interval = interval->next()) {
2323 int assigned_reg = interval->assigned_reg();
2324
2325 assert(interval->current_from() <= op->id() && op->id() <= interval->current_to(), "interval should not be active otherwise");
2326 assert(interval->assigned_regHi() == any_reg, "oop must be single word");
2327 assert(interval->reg_num() >= LIR_OprDesc::vreg_base, "fixed interval found");
2328
2329 // Check if this range covers the instruction. Intervals that
2330 // start or end at the current operation are not included in the
2331 // oop map, except in the case of patching moves. For patching
2332 // moves, any intervals which end at this instruction are included
2333 // in the oop map since we may safepoint while doing the patch
2334 // before we've consumed the inputs.
2335 if (is_patch_info || op->id() < interval->current_to()) {
2336
2337 // caller-save registers must not be included into oop-maps at calls
2338 assert(!is_call_site || assigned_reg >= nof_regs || !is_caller_save(assigned_reg), "interval is in a caller-save register at a call -> register will be overwritten");
2339
2340 VMReg name = vm_reg_for_interval(interval);
2341 map->set_oop(name);
2342
2343 // Spill optimization: when the stack value is guaranteed to be always correct,
2344 // then it must be added to the oop map even if the interval is currently in a register
2345 if (interval->always_in_memory() &&
2346 op->id() > interval->spill_definition_pos() &&
2347 interval->assigned_reg() != interval->canonical_spill_slot()) {
2348 assert(interval->spill_definition_pos() > 0, "position not set correctly");
2349 assert(interval->canonical_spill_slot() >= LinearScan::nof_regs, "no spill slot assigned");
2350 assert(interval->assigned_reg() < LinearScan::nof_regs, "interval is on stack, so stack slot is registered twice");
2351
2352 map->set_oop(frame_map()->slot_regname(interval->canonical_spill_slot() - LinearScan::nof_regs));
2353 }
2354 }
2355 }
2356
2357 // add oops from lock stack
2358 assert(info->stack() != NULL, "CodeEmitInfo must always have a stack");
2359 int locks_count = info->stack()->locks_size();
2360 for (int i = 0; i < locks_count; i++) {
2361 map->set_oop(frame_map()->monitor_object_regname(i));
2362 }
2363
2364 return map;
2365 }
2366
2367
2368 void LinearScan::compute_oop_map(IntervalWalker* iw, const LIR_OpVisitState &visitor, LIR_Op* op) {
2369 assert(visitor.info_count() > 0, "no oop map needed");
2370
2371 // compute oop_map only for first CodeEmitInfo
2372 // because it is (in most cases) equal for all other infos of the same operation
2373 CodeEmitInfo* first_info = visitor.info_at(0);
2374 OopMap* first_oop_map = compute_oop_map(iw, op, first_info, visitor.has_call());
2375
2376 for (int i = 0; i < visitor.info_count(); i++) {
2377 CodeEmitInfo* info = visitor.info_at(i);
2378 OopMap* oop_map = first_oop_map;
2379
2380 if (info->stack()->locks_size() != first_info->stack()->locks_size()) {
2381 // this info has a different number of locks then the precomputed oop map
2382 // (possible for lock and unlock instructions) -> compute oop map with
2383 // correct lock information
2384 oop_map = compute_oop_map(iw, op, info, visitor.has_call());
2385 }
2386
2387 if (info->_oop_map == NULL) {
2388 info->_oop_map = oop_map;
2389 } else {
2390 // a CodeEmitInfo can not be shared between different LIR-instructions
2391 // because interval splitting can occur anywhere between two instructions
2392 // and so the oop maps must be different
2393 // -> check if the already set oop_map is exactly the one calculated for this operation
2394 assert(info->_oop_map == oop_map, "same CodeEmitInfo used for multiple LIR instructions");
2395 }
2396 }
2397 }
2398
2399
2400 // frequently used constants
2401 ConstantOopWriteValue LinearScan::_oop_null_scope_value = ConstantOopWriteValue(NULL);
2402 ConstantIntValue LinearScan::_int_m1_scope_value = ConstantIntValue(-1);
2403 ConstantIntValue LinearScan::_int_0_scope_value = ConstantIntValue(0);
2404 ConstantIntValue LinearScan::_int_1_scope_value = ConstantIntValue(1);
2405 ConstantIntValue LinearScan::_int_2_scope_value = ConstantIntValue(2);
2406 LocationValue _illegal_value = LocationValue(Location());
2407
2408 void LinearScan::init_compute_debug_info() {
2409 // cache for frequently used scope values
2410 // (cpu registers and stack slots)
2411 _scope_value_cache = ScopeValueArray((LinearScan::nof_cpu_regs + frame_map()->argcount() + max_spills()) * 2, NULL);
2412 }
2413
2414 MonitorValue* LinearScan::location_for_monitor_index(int monitor_index) {
2415 Location loc;
2416 if (!frame_map()->location_for_monitor_object(monitor_index, &loc)) {
2417 bailout("too large frame");
2418 }
2419 ScopeValue* object_scope_value = new LocationValue(loc);
2420
2421 if (!frame_map()->location_for_monitor_lock(monitor_index, &loc)) {
2422 bailout("too large frame");
2423 }
2424 return new MonitorValue(object_scope_value, loc);
2425 }
2426
2427 LocationValue* LinearScan::location_for_name(int name, Location::Type loc_type) {
2428 Location loc;
2429 if (!frame_map()->locations_for_slot(name, loc_type, &loc)) {
2430 bailout("too large frame");
2431 }
2432 return new LocationValue(loc);
2433 }
2434
2435
2436 int LinearScan::append_scope_value_for_constant(LIR_Opr opr, GrowableArray<ScopeValue*>* scope_values) {
2437 assert(opr->is_constant(), "should not be called otherwise");
2438
2439 LIR_Const* c = opr->as_constant_ptr();
2440 BasicType t = c->type();
2441 switch (t) {
2442 case T_OBJECT: {
2443 jobject value = c->as_jobject();
2444 if (value == NULL) {
2445 scope_values->append(&_oop_null_scope_value);
2446 } else {
2447 scope_values->append(new ConstantOopWriteValue(c->as_jobject()));
2448 }
2449 return 1;
2450 }
2451
2452 case T_INT: // fall through
2453 case T_FLOAT: {
2454 int value = c->as_jint_bits();
2455 switch (value) {
2456 case -1: scope_values->append(&_int_m1_scope_value); break;
2457 case 0: scope_values->append(&_int_0_scope_value); break;
2458 case 1: scope_values->append(&_int_1_scope_value); break;
2459 case 2: scope_values->append(&_int_2_scope_value); break;
2460 default: scope_values->append(new ConstantIntValue(c->as_jint_bits())); break;
2461 }
2462 return 1;
2463 }
2464
2465 case T_LONG: // fall through
2466 case T_DOUBLE: {
2467 #ifdef _LP64
2468 scope_values->append(&_int_0_scope_value);
2469 scope_values->append(new ConstantLongValue(c->as_jlong_bits()));
2470 #else
2471 if (hi_word_offset_in_bytes > lo_word_offset_in_bytes) {
2472 scope_values->append(new ConstantIntValue(c->as_jint_hi_bits()));
2473 scope_values->append(new ConstantIntValue(c->as_jint_lo_bits()));
2474 } else {
2475 scope_values->append(new ConstantIntValue(c->as_jint_lo_bits()));
2476 scope_values->append(new ConstantIntValue(c->as_jint_hi_bits()));
2477 }
2478 #endif
2479 return 2;
2480 }
2481
2482 case T_ADDRESS: {
2483 #ifdef _LP64
2484 scope_values->append(new ConstantLongValue(c->as_jint()));
2485 #else
2486 scope_values->append(new ConstantIntValue(c->as_jint()));
2487 #endif
2488 return 1;
2489 }
2490
2491 default:
2492 ShouldNotReachHere();
2493 return -1;
2494 }
2495 }
2496
2497 int LinearScan::append_scope_value_for_operand(LIR_Opr opr, GrowableArray<ScopeValue*>* scope_values) {
2498 if (opr->is_single_stack()) {
2499 int stack_idx = opr->single_stack_ix();
2500 bool is_oop = opr->is_oop_register();
2501 int cache_idx = (stack_idx + LinearScan::nof_cpu_regs) * 2 + (is_oop ? 1 : 0);
2502
2503 ScopeValue* sv = _scope_value_cache.at(cache_idx);
2504 if (sv == NULL) {
2505 Location::Type loc_type = is_oop ? Location::oop : Location::normal;
2506 sv = location_for_name(stack_idx, loc_type);
2507 _scope_value_cache.at_put(cache_idx, sv);
2508 }
2509
2510 // check if cached value is correct
2511 DEBUG_ONLY(assert_equal(sv, location_for_name(stack_idx, is_oop ? Location::oop : Location::normal)));
2512
2513 scope_values->append(sv);
2514 return 1;
2515
2516 } else if (opr->is_single_cpu()) {
2517 bool is_oop = opr->is_oop_register();
2518 int cache_idx = opr->cpu_regnr() * 2 + (is_oop ? 1 : 0);
2519 Location::Type int_loc_type = NOT_LP64(Location::normal) LP64_ONLY(Location::int_in_long);
2520
2521 ScopeValue* sv = _scope_value_cache.at(cache_idx);
2522 if (sv == NULL) {
2523 Location::Type loc_type = is_oop ? Location::oop : int_loc_type;
2524 VMReg rname = frame_map()->regname(opr);
2525 sv = new LocationValue(Location::new_reg_loc(loc_type, rname));
2526 _scope_value_cache.at_put(cache_idx, sv);
2527 }
2528
2529 // check if cached value is correct
2530 DEBUG_ONLY(assert_equal(sv, new LocationValue(Location::new_reg_loc(is_oop ? Location::oop : int_loc_type, frame_map()->regname(opr)))));
2531
2532 scope_values->append(sv);
2533 return 1;
2534
2535 #ifdef X86
2536 } else if (opr->is_single_xmm()) {
2537 VMReg rname = opr->as_xmm_float_reg()->as_VMReg();
2538 LocationValue* sv = new LocationValue(Location::new_reg_loc(Location::normal, rname));
2539
2540 scope_values->append(sv);
2541 return 1;
2542 #endif
2543
2544 } else if (opr->is_single_fpu()) {
2545 #ifdef X86
2546 // the exact location of fpu stack values is only known
2547 // during fpu stack allocation, so the stack allocator object
2548 // must be present
2549 assert(use_fpu_stack_allocation(), "should not have float stack values without fpu stack allocation (all floats must be SSE2)");
2550 assert(_fpu_stack_allocator != NULL, "must be present");
2551 opr = _fpu_stack_allocator->to_fpu_stack(opr);
2552 #endif
2553
2554 Location::Type loc_type = float_saved_as_double ? Location::float_in_dbl : Location::normal;
2555 VMReg rname = frame_map()->fpu_regname(opr->fpu_regnr());
2556 LocationValue* sv = new LocationValue(Location::new_reg_loc(loc_type, rname));
2557
2558 scope_values->append(sv);
2559 return 1;
2560
2561 } else {
2562 // double-size operands
2563
2564 ScopeValue* first;
2565 ScopeValue* second;
2566
2567 if (opr->is_double_stack()) {
2568 #ifdef _LP64
2569 Location loc1;
2570 Location::Type loc_type = opr->type() == T_LONG ? Location::lng : Location::dbl;
2571 if (!frame_map()->locations_for_slot(opr->double_stack_ix(), loc_type, &loc1, NULL)) {
2572 bailout("too large frame");
2573 }
2574 // Does this reverse on x86 vs. sparc?
2575 first = new LocationValue(loc1);
2576 second = &_int_0_scope_value;
2577 #else
2578 Location loc1, loc2;
2579 if (!frame_map()->locations_for_slot(opr->double_stack_ix(), Location::normal, &loc1, &loc2)) {
2580 bailout("too large frame");
2581 }
2582 first = new LocationValue(loc1);
2583 second = new LocationValue(loc2);
2584 #endif // _LP64
2585
2586 } else if (opr->is_double_cpu()) {
2587 #ifdef _LP64
2588 VMReg rname_first = opr->as_register_lo()->as_VMReg();
2589 first = new LocationValue(Location::new_reg_loc(Location::lng, rname_first));
2590 second = &_int_0_scope_value;
2591 #else
2592 VMReg rname_first = opr->as_register_lo()->as_VMReg();
2593 VMReg rname_second = opr->as_register_hi()->as_VMReg();
2594
2595 if (hi_word_offset_in_bytes < lo_word_offset_in_bytes) {
2596 // lo/hi and swapped relative to first and second, so swap them
2597 VMReg tmp = rname_first;
2598 rname_first = rname_second;
2599 rname_second = tmp;
2600 }
2601
2602 first = new LocationValue(Location::new_reg_loc(Location::normal, rname_first));
2603 second = new LocationValue(Location::new_reg_loc(Location::normal, rname_second));
2604 #endif //_LP64
2605
2606
2607 #ifdef X86
2608 } else if (opr->is_double_xmm()) {
2609 assert(opr->fpu_regnrLo() == opr->fpu_regnrHi(), "assumed in calculation");
2610 VMReg rname_first = opr->as_xmm_double_reg()->as_VMReg();
2611 # ifdef _LP64
2612 first = new LocationValue(Location::new_reg_loc(Location::dbl, rname_first));
2613 second = &_int_0_scope_value;
2614 # else
2615 first = new LocationValue(Location::new_reg_loc(Location::normal, rname_first));
2616 // %%% This is probably a waste but we'll keep things as they were for now
2617 if (true) {
2618 VMReg rname_second = rname_first->next();
2619 second = new LocationValue(Location::new_reg_loc(Location::normal, rname_second));
2620 }
2621 # endif
2622 #endif
2623
2624 } else if (opr->is_double_fpu()) {
2625 // On SPARC, fpu_regnrLo/fpu_regnrHi represents the two halves of
2626 // the double as float registers in the native ordering. On X86,
2627 // fpu_regnrLo is a FPU stack slot whose VMReg represents
2628 // the low-order word of the double and fpu_regnrLo + 1 is the
2629 // name for the other half. *first and *second must represent the
2630 // least and most significant words, respectively.
2631
2632 #ifdef X86
2633 // the exact location of fpu stack values is only known
2634 // during fpu stack allocation, so the stack allocator object
2635 // must be present
2636 assert(use_fpu_stack_allocation(), "should not have float stack values without fpu stack allocation (all floats must be SSE2)");
2637 assert(_fpu_stack_allocator != NULL, "must be present");
2638 opr = _fpu_stack_allocator->to_fpu_stack(opr);
2639
2640 assert(opr->fpu_regnrLo() == opr->fpu_regnrHi(), "assumed in calculation (only fpu_regnrHi is used)");
2641 #endif
2642 #ifdef SPARC
2643 assert(opr->fpu_regnrLo() == opr->fpu_regnrHi() + 1, "assumed in calculation (only fpu_regnrHi is used)");
2644 #endif
2645
2646 VMReg rname_first = frame_map()->fpu_regname(opr->fpu_regnrHi());
2647 #ifdef _LP64
2648 first = new LocationValue(Location::new_reg_loc(Location::dbl, rname_first));
2649 second = &_int_0_scope_value;
2650 #else
2651 first = new LocationValue(Location::new_reg_loc(Location::normal, rname_first));
2652 // %%% This is probably a waste but we'll keep things as they were for now
2653 if (true) {
2654 VMReg rname_second = rname_first->next();
2655 second = new LocationValue(Location::new_reg_loc(Location::normal, rname_second));
2656 }
2657 #endif
2658
2659 } else {
2660 ShouldNotReachHere();
2661 first = NULL;
2662 second = NULL;
2663 }
2664
2665 assert(first != NULL && second != NULL, "must be set");
2666 // The convention the interpreter uses is that the second local
2667 // holds the first raw word of the native double representation.
2668 // This is actually reasonable, since locals and stack arrays
2669 // grow downwards in all implementations.
2670 // (If, on some machine, the interpreter's Java locals or stack
2671 // were to grow upwards, the embedded doubles would be word-swapped.)
2672 scope_values->append(second);
2673 scope_values->append(first);
2674 return 2;
2675 }
2676 }
2677
2678
2679 int LinearScan::append_scope_value(int op_id, Value value, GrowableArray<ScopeValue*>* scope_values) {
2680 if (value != NULL) {
2681 LIR_Opr opr = value->operand();
2682 Constant* con = value->as_Constant();
2683
2684 assert(con == NULL || opr->is_virtual() || opr->is_constant() || opr->is_illegal(), "asumption: Constant instructions have only constant operands (or illegal if constant is optimized away)");
2685 assert(con != NULL || opr->is_virtual(), "asumption: non-Constant instructions have only virtual operands");
2686
2687 if (con != NULL && !con->is_pinned() && !opr->is_constant()) {
2688 // Unpinned constants may have a virtual operand for a part of the lifetime
2689 // or may be illegal when it was optimized away,
2690 // so always use a constant operand
2691 opr = LIR_OprFact::value_type(con->type());
2692 }
2693 assert(opr->is_virtual() || opr->is_constant(), "other cases not allowed here");
2694
2695 if (opr->is_virtual()) {
2696 LIR_OpVisitState::OprMode mode = LIR_OpVisitState::inputMode;
2697
2698 BlockBegin* block = block_of_op_with_id(op_id);
2699 if (block->number_of_sux() == 1 && op_id == block->last_lir_instruction_id()) {
2700 // generating debug information for the last instruction of a block.
2701 // if this instruction is a branch, spill moves are inserted before this branch
2702 // and so the wrong operand would be returned (spill moves at block boundaries are not
2703 // considered in the live ranges of intervals)
2704 // Solution: use the first op_id of the branch target block instead.
2705 if (block->lir()->instructions_list()->last()->as_OpBranch() != NULL) {
2706 if (block->live_out().at(opr->vreg_number())) {
2707 op_id = block->sux_at(0)->first_lir_instruction_id();
2708 mode = LIR_OpVisitState::outputMode;
2709 }
2710 }
2711 }
2712
2713 // Get current location of operand
2714 // The operand must be live because debug information is considered when building the intervals
2715 // if the interval is not live, color_lir_opr will cause an assertion failure
2716 opr = color_lir_opr(opr, op_id, mode);
2717 assert(!has_call(op_id) || opr->is_stack() || !is_caller_save(reg_num(opr)), "can not have caller-save register operands at calls");
2718
2719 // Append to ScopeValue array
2720 return append_scope_value_for_operand(opr, scope_values);
2721
2722 } else {
2723 assert(value->as_Constant() != NULL, "all other instructions have only virtual operands");
2724 assert(opr->is_constant(), "operand must be constant");
2725
2726 return append_scope_value_for_constant(opr, scope_values);
2727 }
2728 } else {
2729 // append a dummy value because real value not needed
2730 scope_values->append(&_illegal_value);
2731 return 1;
2732 }
2733 }
2734
2735
2736 IRScopeDebugInfo* LinearScan::compute_debug_info_for_scope(int op_id, IRScope* cur_scope, ValueStack* cur_state, ValueStack* innermost_state, int cur_bci, int stack_end, int locks_end) {
2737 IRScopeDebugInfo* caller_debug_info = NULL;
2738 int stack_begin, locks_begin;
2739
2740 ValueStack* caller_state = cur_scope->caller_state();
2741 if (caller_state != NULL) {
2742 // process recursively to compute outermost scope first
2743 stack_begin = caller_state->stack_size();
2744 locks_begin = caller_state->locks_size();
2745 caller_debug_info = compute_debug_info_for_scope(op_id, cur_scope->caller(), caller_state, innermost_state, cur_scope->caller_bci(), stack_begin, locks_begin);
2746 } else {
2747 stack_begin = 0;
2748 locks_begin = 0;
2749 }
2750
2751 // initialize these to null.
2752 // If we don't need deopt info or there are no locals, expressions or monitors,
2753 // then these get recorded as no information and avoids the allocation of 0 length arrays.
2754 GrowableArray<ScopeValue*>* locals = NULL;
2755 GrowableArray<ScopeValue*>* expressions = NULL;
2756 GrowableArray<MonitorValue*>* monitors = NULL;
2757
2758 // describe local variable values
2759 int nof_locals = cur_scope->method()->max_locals();
2760 if (nof_locals > 0) {
2761 locals = new GrowableArray<ScopeValue*>(nof_locals);
2762
2763 int pos = 0;
2764 while (pos < nof_locals) {
2765 assert(pos < cur_state->locals_size(), "why not?");
2766
2767 Value local = cur_state->local_at(pos);
2768 pos += append_scope_value(op_id, local, locals);
2769
2770 assert(locals->length() == pos, "must match");
2771 }
2772 assert(locals->length() == cur_scope->method()->max_locals(), "wrong number of locals");
2773 assert(locals->length() == cur_state->locals_size(), "wrong number of locals");
2774 }
2775
2776
2777 // describe expression stack
2778 //
2779 // When we inline methods containing exception handlers, the
2780 // "lock_stacks" are changed to preserve expression stack values
2781 // in caller scopes when exception handlers are present. This
2782 // can cause callee stacks to be smaller than caller stacks.
2783 if (stack_end > innermost_state->stack_size()) {
2784 stack_end = innermost_state->stack_size();
2785 }
2786
2787
2788
2789 int nof_stack = stack_end - stack_begin;
2790 if (nof_stack > 0) {
2791 expressions = new GrowableArray<ScopeValue*>(nof_stack);
2792
2793 int pos = stack_begin;
2794 while (pos < stack_end) {
2795 Value expression = innermost_state->stack_at_inc(pos);
2796 append_scope_value(op_id, expression, expressions);
2797
2798 assert(expressions->length() + stack_begin == pos, "must match");
2799 }
2800 }
2801
2802 // describe monitors
2803 assert(locks_begin <= locks_end, "error in scope iteration");
2804 int nof_locks = locks_end - locks_begin;
2805 if (nof_locks > 0) {
2806 monitors = new GrowableArray<MonitorValue*>(nof_locks);
2807 for (int i = locks_begin; i < locks_end; i++) {
2808 monitors->append(location_for_monitor_index(i));
2809 }
2810 }
2811
2812 return new IRScopeDebugInfo(cur_scope, cur_bci, locals, expressions, monitors, caller_debug_info);
2813 }
2814
2815
2816 void LinearScan::compute_debug_info(CodeEmitInfo* info, int op_id) {
2817 if (!compilation()->needs_debug_information()) {
2818 return;
2819 }
2820 TRACE_LINEAR_SCAN(3, tty->print_cr("creating debug information at op_id %d", op_id));
2821
2822 IRScope* innermost_scope = info->scope();
2823 ValueStack* innermost_state = info->stack();
2824
2825 assert(innermost_scope != NULL && innermost_state != NULL, "why is it missing?");
2826
2827 int stack_end = innermost_state->stack_size();
2828 int locks_end = innermost_state->locks_size();
2829
2830 DEBUG_ONLY(check_stack_depth(info, stack_end));
2831
2832 if (info->_scope_debug_info == NULL) {
2833 // compute debug information
2834 info->_scope_debug_info = compute_debug_info_for_scope(op_id, innermost_scope, innermost_state, innermost_state, info->bci(), stack_end, locks_end);
2835 } else {
2836 // debug information already set. Check that it is correct from the current point of view
2837 DEBUG_ONLY(assert_equal(info->_scope_debug_info, compute_debug_info_for_scope(op_id, innermost_scope, innermost_state, innermost_state, info->bci(), stack_end, locks_end)));
2838 }
2839 }
2840
2841
2842 void LinearScan::assign_reg_num(LIR_OpList* instructions, IntervalWalker* iw) {
2843 LIR_OpVisitState visitor;
2844 int num_inst = instructions->length();
2845 bool has_dead = false;
2846
2847 for (int j = 0; j < num_inst; j++) {
2848 LIR_Op* op = instructions->at(j);
2849 if (op == NULL) { // this can happen when spill-moves are removed in eliminate_spill_moves
2850 has_dead = true;
2851 continue;
2852 }
2853 int op_id = op->id();
2854
2855 // visit instruction to get list of operands
2856 visitor.visit(op);
2857
2858 // iterate all modes of the visitor and process all virtual operands
2859 for_each_visitor_mode(mode) {
2860 int n = visitor.opr_count(mode);
2861 for (int k = 0; k < n; k++) {
2862 LIR_Opr opr = visitor.opr_at(mode, k);
2863 if (opr->is_virtual_register()) {
2864 visitor.set_opr_at(mode, k, color_lir_opr(opr, op_id, mode));
2865 }
2866 }
2867 }
2868
2869 if (visitor.info_count() > 0) {
2870 // exception handling
2871 if (compilation()->has_exception_handlers()) {
2872 XHandlers* xhandlers = visitor.all_xhandler();
2873 int n = xhandlers->length();
2874 for (int k = 0; k < n; k++) {
2875 XHandler* handler = xhandlers->handler_at(k);
2876 if (handler->entry_code() != NULL) {
2877 assign_reg_num(handler->entry_code()->instructions_list(), NULL);
2878 }
2879 }
2880 } else {
2881 assert(visitor.all_xhandler()->length() == 0, "missed exception handler");
2882 }
2883
2884 // compute oop map
2885 assert(iw != NULL, "needed for compute_oop_map");
2886 compute_oop_map(iw, visitor, op);
2887
2888 // compute debug information
2889 if (!use_fpu_stack_allocation()) {
2890 // compute debug information if fpu stack allocation is not needed.
2891 // when fpu stack allocation is needed, the debug information can not
2892 // be computed here because the exact location of fpu operands is not known
2893 // -> debug information is created inside the fpu stack allocator
2894 int n = visitor.info_count();
2895 for (int k = 0; k < n; k++) {
2896 compute_debug_info(visitor.info_at(k), op_id);
2897 }
2898 }
2899 }
2900
2901 #ifdef ASSERT
2902 // make sure we haven't made the op invalid.
2903 op->verify();
2904 #endif
2905
2906 // remove useless moves
2907 if (op->code() == lir_move) {
2908 assert(op->as_Op1() != NULL, "move must be LIR_Op1");
2909 LIR_Op1* move = (LIR_Op1*)op;
2910 LIR_Opr src = move->in_opr();
2911 LIR_Opr dst = move->result_opr();
2912 if (dst == src ||
2913 !dst->is_pointer() && !src->is_pointer() &&
2914 src->is_same_register(dst)) {
2915 instructions->at_put(j, NULL);
2916 has_dead = true;
2917 }
2918 }
2919 }
2920
2921 if (has_dead) {
2922 // iterate all instructions of the block and remove all null-values.
2923 int insert_point = 0;
2924 for (int j = 0; j < num_inst; j++) {
2925 LIR_Op* op = instructions->at(j);
2926 if (op != NULL) {
2927 if (insert_point != j) {
2928 instructions->at_put(insert_point, op);
2929 }
2930 insert_point++;
2931 }
2932 }
2933 instructions->truncate(insert_point);
2934 }
2935 }
2936
2937 void LinearScan::assign_reg_num() {
2938 TIME_LINEAR_SCAN(timer_assign_reg_num);
2939
2940 init_compute_debug_info();
2941 IntervalWalker* iw = init_compute_oop_maps();
2942
2943 int num_blocks = block_count();
2944 for (int i = 0; i < num_blocks; i++) {
2945 BlockBegin* block = block_at(i);
2946 assign_reg_num(block->lir()->instructions_list(), iw);
2947 }
2948 }
2949
2950
2951 void LinearScan::do_linear_scan() {
2952 NOT_PRODUCT(_total_timer.begin_method());
2953
2954 number_instructions();
2955
2956 NOT_PRODUCT(print_lir(1, "Before Register Allocation"));
2957
2958 compute_local_live_sets();
2959 compute_global_live_sets();
2960 CHECK_BAILOUT();
2961
2962 build_intervals();
2963 CHECK_BAILOUT();
2964 sort_intervals_before_allocation();
2965
2966 NOT_PRODUCT(print_intervals("Before Register Allocation"));
2967 NOT_PRODUCT(LinearScanStatistic::compute(this, _stat_before_alloc));
2968
2969 allocate_registers();
2970 CHECK_BAILOUT();
2971
2972 resolve_data_flow();
2973 if (compilation()->has_exception_handlers()) {
2974 resolve_exception_handlers();
2975 }
2976 // fill in number of spill slots into frame_map
2977 propagate_spill_slots();
2978 CHECK_BAILOUT();
2979
2980 NOT_PRODUCT(print_intervals("After Register Allocation"));
2981 NOT_PRODUCT(print_lir(2, "LIR after register allocation:"));
2982
2983 sort_intervals_after_allocation();
2984
2985 DEBUG_ONLY(verify());
2986
2987 eliminate_spill_moves();
2988 assign_reg_num();
2989 CHECK_BAILOUT();
2990
2991 NOT_PRODUCT(print_lir(2, "LIR after assignment of register numbers:"));
2992 NOT_PRODUCT(LinearScanStatistic::compute(this, _stat_after_asign));
2993
2994 { TIME_LINEAR_SCAN(timer_allocate_fpu_stack);
2995
2996 if (use_fpu_stack_allocation()) {
2997 allocate_fpu_stack(); // Only has effect on Intel
2998 NOT_PRODUCT(print_lir(2, "LIR after FPU stack allocation:"));
2999 }
3000 }
3001
3002 { TIME_LINEAR_SCAN(timer_optimize_lir);
3003
3004 EdgeMoveOptimizer::optimize(ir()->code());
3005 ControlFlowOptimizer::optimize(ir()->code());
3006 // check that cfg is still correct after optimizations
3007 ir()->verify();
3008 }
3009
3010 NOT_PRODUCT(print_lir(1, "Before Code Generation", false));
3011 NOT_PRODUCT(LinearScanStatistic::compute(this, _stat_final));
3012 NOT_PRODUCT(_total_timer.end_method(this));
3013 }
3014
3015
3016 // ********** Printing functions
3017
3018 #ifndef PRODUCT
3019
3020 void LinearScan::print_timers(double total) {
3021 _total_timer.print(total);
3022 }
3023
3024 void LinearScan::print_statistics() {
3025 _stat_before_alloc.print("before allocation");
3026 _stat_after_asign.print("after assignment of register");
3027 _stat_final.print("after optimization");
3028 }
3029
3030 void LinearScan::print_bitmap(BitMap& b) {
3031 for (unsigned int i = 0; i < b.size(); i++) {
3032 if (b.at(i)) tty->print("%d ", i);
3033 }
3034 tty->cr();
3035 }
3036
3037 void LinearScan::print_intervals(const char* label) {
3038 if (TraceLinearScanLevel >= 1) {
3039 int i;
3040 tty->cr();
3041 tty->print_cr("%s", label);
3042
3043 for (i = 0; i < interval_count(); i++) {
3044 Interval* interval = interval_at(i);
3045 if (interval != NULL) {
3046 interval->print();
3047 }
3048 }
3049
3050 tty->cr();
3051 tty->print_cr("--- Basic Blocks ---");
3052 for (i = 0; i < block_count(); i++) {
3053 BlockBegin* block = block_at(i);
3054 tty->print("B%d [%d, %d, %d, %d] ", block->block_id(), block->first_lir_instruction_id(), block->last_lir_instruction_id(), block->loop_index(), block->loop_depth());
3055 }
3056 tty->cr();
3057 tty->cr();
3058 }
3059
3060 if (PrintCFGToFile) {
3061 CFGPrinter::print_intervals(&_intervals, label);
3062 }
3063 }
3064
3065 void LinearScan::print_lir(int level, const char* label, bool hir_valid) {
3066 if (TraceLinearScanLevel >= level) {
3067 tty->cr();
3068 tty->print_cr("%s", label);
3069 print_LIR(ir()->linear_scan_order());
3070 tty->cr();
3071 }
3072
3073 if (level == 1 && PrintCFGToFile) {
3074 CFGPrinter::print_cfg(ir()->linear_scan_order(), label, hir_valid, true);
3075 }
3076 }
3077
3078 #endif //PRODUCT
3079
3080
3081 // ********** verification functions for allocation
3082 // (check that all intervals have a correct register and that no registers are overwritten)
3083 #ifdef ASSERT
3084
3085 void LinearScan::verify() {
3086 TRACE_LINEAR_SCAN(2, tty->print_cr("********* verifying intervals ******************************************"));
3087 verify_intervals();
3088
3089 TRACE_LINEAR_SCAN(2, tty->print_cr("********* verifying that no oops are in fixed intervals ****************"));
3090 verify_no_oops_in_fixed_intervals();
3091
3092 TRACE_LINEAR_SCAN(2, tty->print_cr("********* verifying that unpinned constants are not alive across block boundaries"));
3093 verify_constants();
3094
3095 TRACE_LINEAR_SCAN(2, tty->print_cr("********* verifying register allocation ********************************"));
3096 verify_registers();
3097
3098 TRACE_LINEAR_SCAN(2, tty->print_cr("********* no errors found **********************************************"));
3099 }
3100
3101 void LinearScan::verify_intervals() {
3102 int len = interval_count();
3103 bool has_error = false;
3104
3105 for (int i = 0; i < len; i++) {
3106 Interval* i1 = interval_at(i);
3107 if (i1 == NULL) continue;
3108
3109 i1->check_split_children();
3110
3111 if (i1->reg_num() != i) {
3112 tty->print_cr("Interval %d is on position %d in list", i1->reg_num(), i); i1->print(); tty->cr();
3113 has_error = true;
3114 }
3115
3116 if (i1->reg_num() >= LIR_OprDesc::vreg_base && i1->type() == T_ILLEGAL) {
3117 tty->print_cr("Interval %d has no type assigned", i1->reg_num()); i1->print(); tty->cr();
3118 has_error = true;
3119 }
3120
3121 if (i1->assigned_reg() == any_reg) {
3122 tty->print_cr("Interval %d has no register assigned", i1->reg_num()); i1->print(); tty->cr();
3123 has_error = true;
3124 }
3125
3126 if (i1->assigned_reg() == i1->assigned_regHi()) {
3127 tty->print_cr("Interval %d: low and high register equal", i1->reg_num()); i1->print(); tty->cr();
3128 has_error = true;
3129 }
3130
3131 if (!is_processed_reg_num(i1->assigned_reg())) {
3132 tty->print_cr("Can not have an Interval for an ignored register"); i1->print(); tty->cr();
3133 has_error = true;
3134 }
3135
3136 if (i1->first() == Range::end()) {
3137 tty->print_cr("Interval %d has no Range", i1->reg_num()); i1->print(); tty->cr();
3138 has_error = true;
3139 }
3140
3141 for (Range* r = i1->first(); r != Range::end(); r = r->next()) {
3142 if (r->from() >= r->to()) {
3143 tty->print_cr("Interval %d has zero length range", i1->reg_num()); i1->print(); tty->cr();
3144 has_error = true;
3145 }
3146 }
3147
3148 for (int j = i + 1; j < len; j++) {
3149 Interval* i2 = interval_at(j);
3150 if (i2 == NULL) continue;
3151
3152 // special intervals that are created in MoveResolver
3153 // -> ignore them because the range information has no meaning there
3154 if (i1->from() == 1 && i1->to() == 2) continue;
3155 if (i2->from() == 1 && i2->to() == 2) continue;
3156
3157 int r1 = i1->assigned_reg();
3158 int r1Hi = i1->assigned_regHi();
3159 int r2 = i2->assigned_reg();
3160 int r2Hi = i2->assigned_regHi();
3161 if (i1->intersects(i2) && (r1 == r2 || r1 == r2Hi || (r1Hi != any_reg && (r1Hi == r2 || r1Hi == r2Hi)))) {
3162 tty->print_cr("Intervals %d and %d overlap and have the same register assigned", i1->reg_num(), i2->reg_num());
3163 i1->print(); tty->cr();
3164 i2->print(); tty->cr();
3165 has_error = true;
3166 }
3167 }
3168 }
3169
3170 assert(has_error == false, "register allocation invalid");
3171 }
3172
3173
3174 void LinearScan::verify_no_oops_in_fixed_intervals() {
3175 Interval* fixed_intervals;
3176 Interval* other_intervals;
3177 create_unhandled_lists(&fixed_intervals, &other_intervals, is_precolored_cpu_interval, NULL);
3178
3179 // to ensure a walking until the last instruction id, add a dummy interval
3180 // with a high operation id
3181 other_intervals = new Interval(any_reg);
3182 other_intervals->add_range(max_jint - 2, max_jint - 1);
3183 IntervalWalker* iw = new IntervalWalker(this, fixed_intervals, other_intervals);
3184
3185 LIR_OpVisitState visitor;
3186 for (int i = 0; i < block_count(); i++) {
3187 BlockBegin* block = block_at(i);
3188
3189 LIR_OpList* instructions = block->lir()->instructions_list();
3190
3191 for (int j = 0; j < instructions->length(); j++) {
3192 LIR_Op* op = instructions->at(j);
3193 int op_id = op->id();
3194
3195 visitor.visit(op);
3196
3197 if (visitor.info_count() > 0) {
3198 iw->walk_before(op->id());
3199 bool check_live = true;
3200 if (op->code() == lir_move) {
3201 LIR_Op1* move = (LIR_Op1*)op;
3202 check_live = (move->patch_code() == lir_patch_none);
3203 }
3204 LIR_OpBranch* branch = op->as_OpBranch();
3205 if (branch != NULL && branch->stub() != NULL && branch->stub()->is_exception_throw_stub()) {
3206 // Don't bother checking the stub in this case since the
3207 // exception stub will never return to normal control flow.
3208 check_live = false;
3209 }
3210
3211 // Make sure none of the fixed registers is live across an
3212 // oopmap since we can't handle that correctly.
3213 if (check_live) {
3214 for (Interval* interval = iw->active_first(fixedKind);
3215 interval != Interval::end();
3216 interval = interval->next()) {
3217 if (interval->current_to() > op->id() + 1) {
3218 // This interval is live out of this op so make sure
3219 // that this interval represents some value that's
3220 // referenced by this op either as an input or output.
3221 bool ok = false;
3222 for_each_visitor_mode(mode) {
3223 int n = visitor.opr_count(mode);
3224 for (int k = 0; k < n; k++) {
3225 LIR_Opr opr = visitor.opr_at(mode, k);
3226 if (opr->is_fixed_cpu()) {
3227 if (interval_at(reg_num(opr)) == interval) {
3228 ok = true;
3229 break;
3230 }
3231 int hi = reg_numHi(opr);
3232 if (hi != -1 && interval_at(hi) == interval) {
3233 ok = true;
3234 break;
3235 }
3236 }
3237 }
3238 }
3239 assert(ok, "fixed intervals should never be live across an oopmap point");
3240 }
3241 }
3242 }
3243 }
3244
3245 // oop-maps at calls do not contain registers, so check is not needed
3246 if (!visitor.has_call()) {
3247
3248 for_each_visitor_mode(mode) {
3249 int n = visitor.opr_count(mode);
3250 for (int k = 0; k < n; k++) {
3251 LIR_Opr opr = visitor.opr_at(mode, k);
3252
3253 if (opr->is_fixed_cpu() && opr->is_oop()) {
3254 // operand is a non-virtual cpu register and contains an oop
3255 TRACE_LINEAR_SCAN(4, op->print_on(tty); tty->print("checking operand "); opr->print(); tty->cr());
3256
3257 Interval* interval = interval_at(reg_num(opr));
3258 assert(interval != NULL, "no interval");
3259
3260 if (mode == LIR_OpVisitState::inputMode) {
3261 if (interval->to() >= op_id + 1) {
3262 assert(interval->to() < op_id + 2 ||
3263 interval->has_hole_between(op_id, op_id + 2),
3264 "oop input operand live after instruction");
3265 }
3266 } else if (mode == LIR_OpVisitState::outputMode) {
3267 if (interval->from() <= op_id - 1) {
3268 assert(interval->has_hole_between(op_id - 1, op_id),
3269 "oop input operand live after instruction");
3270 }
3271 }
3272 }
3273 }
3274 }
3275 }
3276 }
3277 }
3278 }
3279
3280
3281 void LinearScan::verify_constants() {
3282 int num_regs = num_virtual_regs();
3283 int size = live_set_size();
3284 int num_blocks = block_count();
3285
3286 for (int i = 0; i < num_blocks; i++) {
3287 BlockBegin* block = block_at(i);
3288 BitMap live_at_edge = block->live_in();
3289
3290 // visit all registers where the live_at_edge bit is set
3291 for (int r = (int)live_at_edge.get_next_one_offset(0, size); r < size; r = (int)live_at_edge.get_next_one_offset(r + 1, size)) {
3292 TRACE_LINEAR_SCAN(4, tty->print("checking interval %d of block B%d", r, block->block_id()));
3293
3294 Value value = gen()->instruction_for_vreg(r);
3295
3296 assert(value != NULL, "all intervals live across block boundaries must have Value");
3297 assert(value->operand()->is_register() && value->operand()->is_virtual(), "value must have virtual operand");
3298 assert(value->operand()->vreg_number() == r, "register number must match");
3299 // TKR assert(value->as_Constant() == NULL || value->is_pinned(), "only pinned constants can be alive accross block boundaries");
3300 }
3301 }
3302 }
3303
3304
3305 class RegisterVerifier: public StackObj {
3306 private:
3307 LinearScan* _allocator;
3308 BlockList _work_list; // all blocks that must be processed
3309 IntervalsList _saved_states; // saved information of previous check
3310
3311 // simplified access to methods of LinearScan
3312 Compilation* compilation() const { return _allocator->compilation(); }
3313 Interval* interval_at(int reg_num) const { return _allocator->interval_at(reg_num); }
3314 int reg_num(LIR_Opr opr) const { return _allocator->reg_num(opr); }
3315
3316 // currently, only registers are processed
3317 int state_size() { return LinearScan::nof_regs; }
3318
3319 // accessors
3320 IntervalList* state_for_block(BlockBegin* block) { return _saved_states.at(block->block_id()); }
3321 void set_state_for_block(BlockBegin* block, IntervalList* saved_state) { _saved_states.at_put(block->block_id(), saved_state); }
3322 void add_to_work_list(BlockBegin* block) { if (!_work_list.contains(block)) _work_list.append(block); }
3323
3324 // helper functions
3325 IntervalList* copy(IntervalList* input_state);
3326 void state_put(IntervalList* input_state, int reg, Interval* interval);
3327 bool check_state(IntervalList* input_state, int reg, Interval* interval);
3328
3329 void process_block(BlockBegin* block);
3330 void process_xhandler(XHandler* xhandler, IntervalList* input_state);
3331 void process_successor(BlockBegin* block, IntervalList* input_state);
3332 void process_operations(LIR_List* ops, IntervalList* input_state);
3333
3334 public:
3335 RegisterVerifier(LinearScan* allocator)
3336 : _allocator(allocator)
3337 , _work_list(16)
3338 , _saved_states(BlockBegin::number_of_blocks(), NULL)
3339 { }
3340
3341 void verify(BlockBegin* start);
3342 };
3343
3344
3345 // entry function from LinearScan that starts the verification
3346 void LinearScan::verify_registers() {
3347 RegisterVerifier verifier(this);
3348 verifier.verify(block_at(0));
3349 }
3350
3351
3352 void RegisterVerifier::verify(BlockBegin* start) {
3353 // setup input registers (method arguments) for first block
3354 IntervalList* input_state = new IntervalList(state_size(), NULL);
3355 CallingConvention* args = compilation()->frame_map()->incoming_arguments();
3356 for (int n = 0; n < args->length(); n++) {
3357 LIR_Opr opr = args->at(n);
3358 if (opr->is_register()) {
3359 Interval* interval = interval_at(reg_num(opr));
3360
3361 if (interval->assigned_reg() < state_size()) {
3362 input_state->at_put(interval->assigned_reg(), interval);
3363 }
3364 if (interval->assigned_regHi() != LinearScan::any_reg && interval->assigned_regHi() < state_size()) {
3365 input_state->at_put(interval->assigned_regHi(), interval);
3366 }
3367 }
3368 }
3369
3370 set_state_for_block(start, input_state);
3371 add_to_work_list(start);
3372
3373 // main loop for verification
3374 do {
3375 BlockBegin* block = _work_list.at(0);
3376 _work_list.remove_at(0);
3377
3378 process_block(block);
3379 } while (!_work_list.is_empty());
3380 }
3381
3382 void RegisterVerifier::process_block(BlockBegin* block) {
3383 TRACE_LINEAR_SCAN(2, tty->cr(); tty->print_cr("process_block B%d", block->block_id()));
3384
3385 // must copy state because it is modified
3386 IntervalList* input_state = copy(state_for_block(block));
3387
3388 if (TraceLinearScanLevel >= 4) {
3389 tty->print_cr("Input-State of intervals:");
3390 tty->print(" ");
3391 for (int i = 0; i < state_size(); i++) {
3392 if (input_state->at(i) != NULL) {
3393 tty->print(" %4d", input_state->at(i)->reg_num());
3394 } else {
3395 tty->print(" __");
3396 }
3397 }
3398 tty->cr();
3399 tty->cr();
3400 }
3401
3402 // process all operations of the block
3403 process_operations(block->lir(), input_state);
3404
3405 // iterate all successors
3406 for (int i = 0; i < block->number_of_sux(); i++) {
3407 process_successor(block->sux_at(i), input_state);
3408 }
3409 }
3410
3411 void RegisterVerifier::process_xhandler(XHandler* xhandler, IntervalList* input_state) {
3412 TRACE_LINEAR_SCAN(2, tty->print_cr("process_xhandler B%d", xhandler->entry_block()->block_id()));
3413
3414 // must copy state because it is modified
3415 input_state = copy(input_state);
3416
3417 if (xhandler->entry_code() != NULL) {
3418 process_operations(xhandler->entry_code(), input_state);
3419 }
3420 process_successor(xhandler->entry_block(), input_state);
3421 }
3422
3423 void RegisterVerifier::process_successor(BlockBegin* block, IntervalList* input_state) {
3424 IntervalList* saved_state = state_for_block(block);
3425
3426 if (saved_state != NULL) {
3427 // this block was already processed before.
3428 // check if new input_state is consistent with saved_state
3429
3430 bool saved_state_correct = true;
3431 for (int i = 0; i < state_size(); i++) {
3432 if (input_state->at(i) != saved_state->at(i)) {
3433 // current input_state and previous saved_state assume a different
3434 // interval in this register -> assume that this register is invalid
3435 if (saved_state->at(i) != NULL) {
3436 // invalidate old calculation only if it assumed that
3437 // register was valid. when the register was already invalid,
3438 // then the old calculation was correct.
3439 saved_state_correct = false;
3440 saved_state->at_put(i, NULL);
3441
3442 TRACE_LINEAR_SCAN(4, tty->print_cr("process_successor B%d: invalidating slot %d", block->block_id(), i));
3443 }
3444 }
3445 }
3446
3447 if (saved_state_correct) {
3448 // already processed block with correct input_state
3449 TRACE_LINEAR_SCAN(2, tty->print_cr("process_successor B%d: previous visit already correct", block->block_id()));
3450 } else {
3451 // must re-visit this block
3452 TRACE_LINEAR_SCAN(2, tty->print_cr("process_successor B%d: must re-visit because input state changed", block->block_id()));
3453 add_to_work_list(block);
3454 }
3455
3456 } else {
3457 // block was not processed before, so set initial input_state
3458 TRACE_LINEAR_SCAN(2, tty->print_cr("process_successor B%d: initial visit", block->block_id()));
3459
3460 set_state_for_block(block, copy(input_state));
3461 add_to_work_list(block);
3462 }
3463 }
3464
3465
3466 IntervalList* RegisterVerifier::copy(IntervalList* input_state) {
3467 IntervalList* copy_state = new IntervalList(input_state->length());
3468 copy_state->push_all(input_state);
3469 return copy_state;
3470 }
3471
3472 void RegisterVerifier::state_put(IntervalList* input_state, int reg, Interval* interval) {
3473 if (reg != LinearScan::any_reg && reg < state_size()) {
3474 if (interval != NULL) {
3475 TRACE_LINEAR_SCAN(4, tty->print_cr(" reg[%d] = %d", reg, interval->reg_num()));
3476 } else if (input_state->at(reg) != NULL) {
3477 TRACE_LINEAR_SCAN(4, tty->print_cr(" reg[%d] = NULL", reg));
3478 }
3479
3480 input_state->at_put(reg, interval);
3481 }
3482 }
3483
3484 bool RegisterVerifier::check_state(IntervalList* input_state, int reg, Interval* interval) {
3485 if (reg != LinearScan::any_reg && reg < state_size()) {
3486 if (input_state->at(reg) != interval) {
3487 tty->print_cr("!! Error in register allocation: register %d does not contain interval %d", reg, interval->reg_num());
3488 return true;
3489 }
3490 }
3491 return false;
3492 }
3493
3494 void RegisterVerifier::process_operations(LIR_List* ops, IntervalList* input_state) {
3495 // visit all instructions of the block
3496 LIR_OpVisitState visitor;
3497 bool has_error = false;
3498
3499 for (int i = 0; i < ops->length(); i++) {
3500 LIR_Op* op = ops->at(i);
3501 visitor.visit(op);
3502
3503 TRACE_LINEAR_SCAN(4, op->print_on(tty));
3504
3505 // check if input operands are correct
3506 int j;
3507 int n = visitor.opr_count(LIR_OpVisitState::inputMode);
3508 for (j = 0; j < n; j++) {
3509 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::inputMode, j);
3510 if (opr->is_register() && LinearScan::is_processed_reg_num(reg_num(opr))) {
3511 Interval* interval = interval_at(reg_num(opr));
3512 if (op->id() != -1) {
3513 interval = interval->split_child_at_op_id(op->id(), LIR_OpVisitState::inputMode);
3514 }
3515
3516 has_error |= check_state(input_state, interval->assigned_reg(), interval->split_parent());
3517 has_error |= check_state(input_state, interval->assigned_regHi(), interval->split_parent());
3518
3519 // When an operand is marked with is_last_use, then the fpu stack allocator
3520 // removes the register from the fpu stack -> the register contains no value
3521 if (opr->is_last_use()) {
3522 state_put(input_state, interval->assigned_reg(), NULL);
3523 state_put(input_state, interval->assigned_regHi(), NULL);
3524 }
3525 }
3526 }
3527
3528 // invalidate all caller save registers at calls
3529 if (visitor.has_call()) {
3530 for (j = 0; j < FrameMap::nof_caller_save_cpu_regs; j++) {
3531 state_put(input_state, reg_num(FrameMap::caller_save_cpu_reg_at(j)), NULL);
3532 }
3533 for (j = 0; j < FrameMap::nof_caller_save_fpu_regs; j++) {
3534 state_put(input_state, reg_num(FrameMap::caller_save_fpu_reg_at(j)), NULL);
3535 }
3536
3537 #ifdef X86
3538 for (j = 0; j < FrameMap::nof_caller_save_xmm_regs; j++) {
3539 state_put(input_state, reg_num(FrameMap::caller_save_xmm_reg_at(j)), NULL);
3540 }
3541 #endif
3542 }
3543
3544 // process xhandler before output and temp operands
3545 XHandlers* xhandlers = visitor.all_xhandler();
3546 n = xhandlers->length();
3547 for (int k = 0; k < n; k++) {
3548 process_xhandler(xhandlers->handler_at(k), input_state);
3549 }
3550
3551 // set temp operands (some operations use temp operands also as output operands, so can't set them NULL)
3552 n = visitor.opr_count(LIR_OpVisitState::tempMode);
3553 for (j = 0; j < n; j++) {
3554 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::tempMode, j);
3555 if (opr->is_register() && LinearScan::is_processed_reg_num(reg_num(opr))) {
3556 Interval* interval = interval_at(reg_num(opr));
3557 if (op->id() != -1) {
3558 interval = interval->split_child_at_op_id(op->id(), LIR_OpVisitState::tempMode);
3559 }
3560
3561 state_put(input_state, interval->assigned_reg(), interval->split_parent());
3562 state_put(input_state, interval->assigned_regHi(), interval->split_parent());
3563 }
3564 }
3565
3566 // set output operands
3567 n = visitor.opr_count(LIR_OpVisitState::outputMode);
3568 for (j = 0; j < n; j++) {
3569 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::outputMode, j);
3570 if (opr->is_register() && LinearScan::is_processed_reg_num(reg_num(opr))) {
3571 Interval* interval = interval_at(reg_num(opr));
3572 if (op->id() != -1) {
3573 interval = interval->split_child_at_op_id(op->id(), LIR_OpVisitState::outputMode);
3574 }
3575
3576 state_put(input_state, interval->assigned_reg(), interval->split_parent());
3577 state_put(input_state, interval->assigned_regHi(), interval->split_parent());
3578 }
3579 }
3580 }
3581 assert(has_error == false, "Error in register allocation");
3582 }
3583
3584 #endif // ASSERT
3585
3586
3587
3588 // **** Implementation of MoveResolver ******************************
3589
3590 MoveResolver::MoveResolver(LinearScan* allocator) :
3591 _allocator(allocator),
3592 _multiple_reads_allowed(false),
3593 _mapping_from(8),
3594 _mapping_from_opr(8),
3595 _mapping_to(8),
3596 _insert_list(NULL),
3597 _insert_idx(-1),
3598 _insertion_buffer()
3599 {
3600 for (int i = 0; i < LinearScan::nof_regs; i++) {
3601 _register_blocked[i] = 0;
3602 }
3603 DEBUG_ONLY(check_empty());
3604 }
3605
3606
3607 #ifdef ASSERT
3608
3609 void MoveResolver::check_empty() {
3610 assert(_mapping_from.length() == 0 && _mapping_from_opr.length() == 0 && _mapping_to.length() == 0, "list must be empty before and after processing");
3611 for (int i = 0; i < LinearScan::nof_regs; i++) {
3612 assert(register_blocked(i) == 0, "register map must be empty before and after processing");
3613 }
3614 assert(_multiple_reads_allowed == false, "must have default value");
3615 }
3616
3617 void MoveResolver::verify_before_resolve() {
3618 assert(_mapping_from.length() == _mapping_from_opr.length(), "length must be equal");
3619 assert(_mapping_from.length() == _mapping_to.length(), "length must be equal");
3620 assert(_insert_list != NULL && _insert_idx != -1, "insert position not set");
3621
3622 int i, j;
3623 if (!_multiple_reads_allowed) {
3624 for (i = 0; i < _mapping_from.length(); i++) {
3625 for (j = i + 1; j < _mapping_from.length(); j++) {
3626 assert(_mapping_from.at(i) == NULL || _mapping_from.at(i) != _mapping_from.at(j), "cannot read from same interval twice");
3627 }
3628 }
3629 }
3630
3631 for (i = 0; i < _mapping_to.length(); i++) {
3632 for (j = i + 1; j < _mapping_to.length(); j++) {
3633 assert(_mapping_to.at(i) != _mapping_to.at(j), "cannot write to same interval twice");
3634 }
3635 }
3636
3637
3638 BitMap used_regs(LinearScan::nof_regs + allocator()->frame_map()->argcount() + allocator()->max_spills());
3639 used_regs.clear();
3640 if (!_multiple_reads_allowed) {
3641 for (i = 0; i < _mapping_from.length(); i++) {
3642 Interval* it = _mapping_from.at(i);
3643 if (it != NULL) {
3644 assert(!used_regs.at(it->assigned_reg()), "cannot read from same register twice");
3645 used_regs.set_bit(it->assigned_reg());
3646
3647 if (it->assigned_regHi() != LinearScan::any_reg) {
3648 assert(!used_regs.at(it->assigned_regHi()), "cannot read from same register twice");
3649 used_regs.set_bit(it->assigned_regHi());
3650 }
3651 }
3652 }
3653 }
3654
3655 used_regs.clear();
3656 for (i = 0; i < _mapping_to.length(); i++) {
3657 Interval* it = _mapping_to.at(i);
3658 assert(!used_regs.at(it->assigned_reg()), "cannot write to same register twice");
3659 used_regs.set_bit(it->assigned_reg());
3660
3661 if (it->assigned_regHi() != LinearScan::any_reg) {
3662 assert(!used_regs.at(it->assigned_regHi()), "cannot write to same register twice");
3663 used_regs.set_bit(it->assigned_regHi());
3664 }
3665 }
3666
3667 used_regs.clear();
3668 for (i = 0; i < _mapping_from.length(); i++) {
3669 Interval* it = _mapping_from.at(i);
3670 if (it != NULL && it->assigned_reg() >= LinearScan::nof_regs) {
3671 used_regs.set_bit(it->assigned_reg());
3672 }
3673 }
3674 for (i = 0; i < _mapping_to.length(); i++) {
3675 Interval* it = _mapping_to.at(i);
3676 assert(!used_regs.at(it->assigned_reg()) || it->assigned_reg() == _mapping_from.at(i)->assigned_reg(), "stack slots used in _mapping_from must be disjoint to _mapping_to");
3677 }
3678 }
3679
3680 #endif // ASSERT
3681
3682
3683 // mark assigned_reg and assigned_regHi of the interval as blocked
3684 void MoveResolver::block_registers(Interval* it) {
3685 int reg = it->assigned_reg();
3686 if (reg < LinearScan::nof_regs) {
3687 assert(_multiple_reads_allowed || register_blocked(reg) == 0, "register already marked as used");
3688 set_register_blocked(reg, 1);
3689 }
3690 reg = it->assigned_regHi();
3691 if (reg != LinearScan::any_reg && reg < LinearScan::nof_regs) {
3692 assert(_multiple_reads_allowed || register_blocked(reg) == 0, "register already marked as used");
3693 set_register_blocked(reg, 1);
3694 }
3695 }
3696
3697 // mark assigned_reg and assigned_regHi of the interval as unblocked
3698 void MoveResolver::unblock_registers(Interval* it) {
3699 int reg = it->assigned_reg();
3700 if (reg < LinearScan::nof_regs) {
3701 assert(register_blocked(reg) > 0, "register already marked as unused");
3702 set_register_blocked(reg, -1);
3703 }
3704 reg = it->assigned_regHi();
3705 if (reg != LinearScan::any_reg && reg < LinearScan::nof_regs) {
3706 assert(register_blocked(reg) > 0, "register already marked as unused");
3707 set_register_blocked(reg, -1);
3708 }
3709 }
3710
3711 // check if assigned_reg and assigned_regHi of the to-interval are not blocked (or only blocked by from)
3712 bool MoveResolver::save_to_process_move(Interval* from, Interval* to) {
3713 int from_reg = -1;
3714 int from_regHi = -1;
3715 if (from != NULL) {
3716 from_reg = from->assigned_reg();
3717 from_regHi = from->assigned_regHi();
3718 }
3719
3720 int reg = to->assigned_reg();
3721 if (reg < LinearScan::nof_regs) {
3722 if (register_blocked(reg) > 1 || (register_blocked(reg) == 1 && reg != from_reg && reg != from_regHi)) {
3723 return false;
3724 }
3725 }
3726 reg = to->assigned_regHi();
3727 if (reg != LinearScan::any_reg && reg < LinearScan::nof_regs) {
3728 if (register_blocked(reg) > 1 || (register_blocked(reg) == 1 && reg != from_reg && reg != from_regHi)) {
3729 return false;
3730 }
3731 }
3732
3733 return true;
3734 }
3735
3736
3737 void MoveResolver::create_insertion_buffer(LIR_List* list) {
3738 assert(!_insertion_buffer.initialized(), "overwriting existing buffer");
3739 _insertion_buffer.init(list);
3740 }
3741
3742 void MoveResolver::append_insertion_buffer() {
3743 if (_insertion_buffer.initialized()) {
3744 _insertion_buffer.lir_list()->append(&_insertion_buffer);
3745 }
3746 assert(!_insertion_buffer.initialized(), "must be uninitialized now");
3747
3748 _insert_list = NULL;
3749 _insert_idx = -1;
3750 }
3751
3752 void MoveResolver::insert_move(Interval* from_interval, Interval* to_interval) {
3753 assert(from_interval->reg_num() != to_interval->reg_num(), "from and to interval equal");
3754 assert(from_interval->type() == to_interval->type(), "move between different types");
3755 assert(_insert_list != NULL && _insert_idx != -1, "must setup insert position first");
3756 assert(_insertion_buffer.lir_list() == _insert_list, "wrong insertion buffer");
3757
3758 LIR_Opr from_opr = LIR_OprFact::virtual_register(from_interval->reg_num(), from_interval->type());
3759 LIR_Opr to_opr = LIR_OprFact::virtual_register(to_interval->reg_num(), to_interval->type());
3760
3761 if (!_multiple_reads_allowed) {
3762 // the last_use flag is an optimization for FPU stack allocation. When the same
3763 // input interval is used in more than one move, then it is too difficult to determine
3764 // if this move is really the last use.
3765 from_opr = from_opr->make_last_use();
3766 }
3767 _insertion_buffer.move(_insert_idx, from_opr, to_opr);
3768
3769 TRACE_LINEAR_SCAN(4, tty->print_cr("MoveResolver: inserted move from register %d (%d, %d) to %d (%d, %d)", from_interval->reg_num(), from_interval->assigned_reg(), from_interval->assigned_regHi(), to_interval->reg_num(), to_interval->assigned_reg(), to_interval->assigned_regHi()));
3770 }
3771
3772 void MoveResolver::insert_move(LIR_Opr from_opr, Interval* to_interval) {
3773 assert(from_opr->type() == to_interval->type(), "move between different types");
3774 assert(_insert_list != NULL && _insert_idx != -1, "must setup insert position first");
3775 assert(_insertion_buffer.lir_list() == _insert_list, "wrong insertion buffer");
3776
3777 LIR_Opr to_opr = LIR_OprFact::virtual_register(to_interval->reg_num(), to_interval->type());
3778 _insertion_buffer.move(_insert_idx, from_opr, to_opr);
3779
3780 TRACE_LINEAR_SCAN(4, tty->print("MoveResolver: inserted move from constant "); from_opr->print(); tty->print_cr(" to %d (%d, %d)", to_interval->reg_num(), to_interval->assigned_reg(), to_interval->assigned_regHi()));
3781 }
3782
3783
3784 void MoveResolver::resolve_mappings() {
3785 TRACE_LINEAR_SCAN(4, tty->print_cr("MoveResolver: resolving mappings for Block B%d, index %d", _insert_list->block() != NULL ? _insert_list->block()->block_id() : -1, _insert_idx));
3786 DEBUG_ONLY(verify_before_resolve());
3787
3788 // Block all registers that are used as input operands of a move.
3789 // When a register is blocked, no move to this register is emitted.
3790 // This is necessary for detecting cycles in moves.
3791 int i;
3792 for (i = _mapping_from.length() - 1; i >= 0; i--) {
3793 Interval* from_interval = _mapping_from.at(i);
3794 if (from_interval != NULL) {
3795 block_registers(from_interval);
3796 }
3797 }
3798
3799 int spill_candidate = -1;
3800 while (_mapping_from.length() > 0) {
3801 bool processed_interval = false;
3802
3803 for (i = _mapping_from.length() - 1; i >= 0; i--) {
3804 Interval* from_interval = _mapping_from.at(i);
3805 Interval* to_interval = _mapping_to.at(i);
3806
3807 if (save_to_process_move(from_interval, to_interval)) {
3808 // this inverval can be processed because target is free
3809 if (from_interval != NULL) {
3810 insert_move(from_interval, to_interval);
3811 unblock_registers(from_interval);
3812 } else {
3813 insert_move(_mapping_from_opr.at(i), to_interval);
3814 }
3815 _mapping_from.remove_at(i);
3816 _mapping_from_opr.remove_at(i);
3817 _mapping_to.remove_at(i);
3818
3819 processed_interval = true;
3820 } else if (from_interval != NULL && from_interval->assigned_reg() < LinearScan::nof_regs) {
3821 // this interval cannot be processed now because target is not free
3822 // it starts in a register, so it is a possible candidate for spilling
3823 spill_candidate = i;
3824 }
3825 }
3826
3827 if (!processed_interval) {
3828 // no move could be processed because there is a cycle in the move list
3829 // (e.g. r1 -> r2, r2 -> r1), so one interval must be spilled to memory
3830 assert(spill_candidate != -1, "no interval in register for spilling found");
3831
3832 // create a new spill interval and assign a stack slot to it
3833 Interval* from_interval = _mapping_from.at(spill_candidate);
3834 Interval* spill_interval = new Interval(-1);
3835 spill_interval->set_type(from_interval->type());
3836
3837 // add a dummy range because real position is difficult to calculate
3838 // Note: this range is a special case when the integrity of the allocation is checked
3839 spill_interval->add_range(1, 2);
3840
3841 // do not allocate a new spill slot for temporary interval, but
3842 // use spill slot assigned to from_interval. Otherwise moves from
3843 // one stack slot to another can happen (not allowed by LIR_Assembler
3844 int spill_slot = from_interval->canonical_spill_slot();
3845 if (spill_slot < 0) {
3846 spill_slot = allocator()->allocate_spill_slot(type2spill_size[spill_interval->type()] == 2);
3847 from_interval->set_canonical_spill_slot(spill_slot);
3848 }
3849 spill_interval->assign_reg(spill_slot);
3850 allocator()->append_interval(spill_interval);
3851
3852 TRACE_LINEAR_SCAN(4, tty->print_cr("created new Interval %d for spilling", spill_interval->reg_num()));
3853
3854 // insert a move from register to stack and update the mapping
3855 insert_move(from_interval, spill_interval);
3856 _mapping_from.at_put(spill_candidate, spill_interval);
3857 unblock_registers(from_interval);
3858 }
3859 }
3860
3861 // reset to default value
3862 _multiple_reads_allowed = false;
3863
3864 // check that all intervals have been processed
3865 DEBUG_ONLY(check_empty());
3866 }
3867
3868
3869 void MoveResolver::set_insert_position(LIR_List* insert_list, int insert_idx) {
3870 TRACE_LINEAR_SCAN(4, tty->print_cr("MoveResolver: setting insert position to Block B%d, index %d", insert_list->block() != NULL ? insert_list->block()->block_id() : -1, insert_idx));
3871 assert(_insert_list == NULL && _insert_idx == -1, "use move_insert_position instead of set_insert_position when data already set");
3872
3873 create_insertion_buffer(insert_list);
3874 _insert_list = insert_list;
3875 _insert_idx = insert_idx;
3876 }
3877
3878 void MoveResolver::move_insert_position(LIR_List* insert_list, int insert_idx) {
3879 TRACE_LINEAR_SCAN(4, tty->print_cr("MoveResolver: moving insert position to Block B%d, index %d", insert_list->block() != NULL ? insert_list->block()->block_id() : -1, insert_idx));
3880
3881 if (_insert_list != NULL && (insert_list != _insert_list || insert_idx != _insert_idx)) {
3882 // insert position changed -> resolve current mappings
3883 resolve_mappings();
3884 }
3885
3886 if (insert_list != _insert_list) {
3887 // block changed -> append insertion_buffer because it is
3888 // bound to a specific block and create a new insertion_buffer
3889 append_insertion_buffer();
3890 create_insertion_buffer(insert_list);
3891 }
3892
3893 _insert_list = insert_list;
3894 _insert_idx = insert_idx;
3895 }
3896
3897 void MoveResolver::add_mapping(Interval* from_interval, Interval* to_interval) {
3898 TRACE_LINEAR_SCAN(4, tty->print_cr("MoveResolver: adding mapping from %d (%d, %d) to %d (%d, %d)", from_interval->reg_num(), from_interval->assigned_reg(), from_interval->assigned_regHi(), to_interval->reg_num(), to_interval->assigned_reg(), to_interval->assigned_regHi()));
3899
3900 _mapping_from.append(from_interval);
3901 _mapping_from_opr.append(LIR_OprFact::illegalOpr);
3902 _mapping_to.append(to_interval);
3903 }
3904
3905
3906 void MoveResolver::add_mapping(LIR_Opr from_opr, Interval* to_interval) {
3907 TRACE_LINEAR_SCAN(4, tty->print("MoveResolver: adding mapping from "); from_opr->print(); tty->print_cr(" to %d (%d, %d)", to_interval->reg_num(), to_interval->assigned_reg(), to_interval->assigned_regHi()));
3908 assert(from_opr->is_constant(), "only for constants");
3909
3910 _mapping_from.append(NULL);
3911 _mapping_from_opr.append(from_opr);
3912 _mapping_to.append(to_interval);
3913 }
3914
3915 void MoveResolver::resolve_and_append_moves() {
3916 if (has_mappings()) {
3917 resolve_mappings();
3918 }
3919 append_insertion_buffer();
3920 }
3921
3922
3923
3924 // **** Implementation of Range *************************************
3925
3926 Range::Range(int from, int to, Range* next) :
3927 _from(from),
3928 _to(to),
3929 _next(next)
3930 {
3931 }
3932
3933 // initialize sentinel
3934 Range* Range::_end = NULL;
3935 void Range::initialize() {
3936 _end = new Range(max_jint, max_jint, NULL);
3937 }
3938
3939 int Range::intersects_at(Range* r2) const {
3940 const Range* r1 = this;
3941
3942 assert(r1 != NULL && r2 != NULL, "null ranges not allowed");
3943 assert(r1 != _end && r2 != _end, "empty ranges not allowed");
3944
3945 do {
3946 if (r1->from() < r2->from()) {
3947 if (r1->to() <= r2->from()) {
3948 r1 = r1->next(); if (r1 == _end) return -1;
3949 } else {
3950 return r2->from();
3951 }
3952 } else if (r2->from() < r1->from()) {
3953 if (r2->to() <= r1->from()) {
3954 r2 = r2->next(); if (r2 == _end) return -1;
3955 } else {
3956 return r1->from();
3957 }
3958 } else { // r1->from() == r2->from()
3959 if (r1->from() == r1->to()) {
3960 r1 = r1->next(); if (r1 == _end) return -1;
3961 } else if (r2->from() == r2->to()) {
3962 r2 = r2->next(); if (r2 == _end) return -1;
3963 } else {
3964 return r1->from();
3965 }
3966 }
3967 } while (true);
3968 }
3969
3970 #ifndef PRODUCT
3971 void Range::print(outputStream* out) const {
3972 out->print("[%d, %d[ ", _from, _to);
3973 }
3974 #endif
3975
3976
3977
3978 // **** Implementation of Interval **********************************
3979
3980 // initialize sentinel
3981 Interval* Interval::_end = NULL;
3982 void Interval::initialize() {
3983 Range::initialize();
3984 _end = new Interval(-1);
3985 }
3986
3987 Interval::Interval(int reg_num) :
3988 _reg_num(reg_num),
3989 _type(T_ILLEGAL),
3990 _first(Range::end()),
3991 _use_pos_and_kinds(12),
3992 _current(Range::end()),
3993 _next(_end),
3994 _state(invalidState),
3995 _assigned_reg(LinearScan::any_reg),
3996 _assigned_regHi(LinearScan::any_reg),
3997 _cached_to(-1),
3998 _cached_opr(LIR_OprFact::illegalOpr),
3999 _cached_vm_reg(VMRegImpl::Bad()),
4000 _split_children(0),
4001 _canonical_spill_slot(-1),
4002 _insert_move_when_activated(false),
4003 _register_hint(NULL),
4004 _spill_state(noDefinitionFound),
4005 _spill_definition_pos(-1)
4006 {
4007 _split_parent = this;
4008 _current_split_child = this;
4009 }
4010
4011 int Interval::calc_to() {
4012 assert(_first != Range::end(), "interval has no range");
4013
4014 Range* r = _first;
4015 while (r->next() != Range::end()) {
4016 r = r->next();
4017 }
4018 return r->to();
4019 }
4020
4021
4022 #ifdef ASSERT
4023 // consistency check of split-children
4024 void Interval::check_split_children() {
4025 if (_split_children.length() > 0) {
4026 assert(is_split_parent(), "only split parents can have children");
4027
4028 for (int i = 0; i < _split_children.length(); i++) {
4029 Interval* i1 = _split_children.at(i);
4030
4031 assert(i1->split_parent() == this, "not a split child of this interval");
4032 assert(i1->type() == type(), "must be equal for all split children");
4033 assert(i1->canonical_spill_slot() == canonical_spill_slot(), "must be equal for all split children");
4034
4035 for (int j = i + 1; j < _split_children.length(); j++) {
4036 Interval* i2 = _split_children.at(j);
4037
4038 assert(i1->reg_num() != i2->reg_num(), "same register number");
4039
4040 if (i1->from() < i2->from()) {
4041 assert(i1->to() <= i2->from() && i1->to() < i2->to(), "intervals overlapping");
4042 } else {
4043 assert(i2->from() < i1->from(), "intervals start at same op_id");
4044 assert(i2->to() <= i1->from() && i2->to() < i1->to(), "intervals overlapping");
4045 }
4046 }
4047 }
4048 }
4049 }
4050 #endif // ASSERT
4051
4052 Interval* Interval::register_hint(bool search_split_child) const {
4053 if (!search_split_child) {
4054 return _register_hint;
4055 }
4056
4057 if (_register_hint != NULL) {
4058 assert(_register_hint->is_split_parent(), "ony split parents are valid hint registers");
4059
4060 if (_register_hint->assigned_reg() >= 0 && _register_hint->assigned_reg() < LinearScan::nof_regs) {
4061 return _register_hint;
4062
4063 } else if (_register_hint->_split_children.length() > 0) {
4064 // search the first split child that has a register assigned
4065 int len = _register_hint->_split_children.length();
4066 for (int i = 0; i < len; i++) {
4067 Interval* cur = _register_hint->_split_children.at(i);
4068
4069 if (cur->assigned_reg() >= 0 && cur->assigned_reg() < LinearScan::nof_regs) {
4070 return cur;
4071 }
4072 }
4073 }
4074 }
4075
4076 // no hint interval found that has a register assigned
4077 return NULL;
4078 }
4079
4080
4081 Interval* Interval::split_child_at_op_id(int op_id, LIR_OpVisitState::OprMode mode) {
4082 assert(is_split_parent(), "can only be called for split parents");
4083 assert(op_id >= 0, "invalid op_id (method can not be called for spill moves)");
4084
4085 Interval* result;
4086 if (_split_children.length() == 0) {
4087 result = this;
4088 } else {
4089 result = NULL;
4090 int len = _split_children.length();
4091
4092 // in outputMode, the end of the interval (op_id == cur->to()) is not valid
4093 int to_offset = (mode == LIR_OpVisitState::outputMode ? 0 : 1);
4094
4095 int i;
4096 for (i = 0; i < len; i++) {
4097 Interval* cur = _split_children.at(i);
4098 if (cur->from() <= op_id && op_id < cur->to() + to_offset) {
4099 if (i > 0) {
4100 // exchange current split child to start of list (faster access for next call)
4101 _split_children.at_put(i, _split_children.at(0));
4102 _split_children.at_put(0, cur);
4103 }
4104
4105 // interval found
4106 result = cur;
4107 break;
4108 }
4109 }
4110
4111 #ifdef ASSERT
4112 for (i = 0; i < len; i++) {
4113 Interval* tmp = _split_children.at(i);
4114 if (tmp != result && tmp->from() <= op_id && op_id < tmp->to() + to_offset) {
4115 tty->print_cr("two valid result intervals found for op_id %d: %d and %d", op_id, result->reg_num(), tmp->reg_num());
4116 result->print();
4117 tmp->print();
4118 assert(false, "two valid result intervals found");
4119 }
4120 }
4121 #endif
4122 }
4123
4124 assert(result != NULL, "no matching interval found");
4125 assert(result->covers(op_id, mode), "op_id not covered by interval");
4126
4127 return result;
4128 }
4129
4130
4131 // returns the last split child that ends before the given op_id
4132 Interval* Interval::split_child_before_op_id(int op_id) {
4133 assert(op_id >= 0, "invalid op_id");
4134
4135 Interval* parent = split_parent();
4136 Interval* result = NULL;
4137
4138 int len = parent->_split_children.length();
4139 assert(len > 0, "no split children available");
4140
4141 for (int i = len - 1; i >= 0; i--) {
4142 Interval* cur = parent->_split_children.at(i);
4143 if (cur->to() <= op_id && (result == NULL || result->to() < cur->to())) {
4144 result = cur;
4145 }
4146 }
4147
4148 assert(result != NULL, "no split child found");
4149 return result;
4150 }
4151
4152
4153 // checks if op_id is covered by any split child
4154 bool Interval::split_child_covers(int op_id, LIR_OpVisitState::OprMode mode) {
4155 assert(is_split_parent(), "can only be called for split parents");
4156 assert(op_id >= 0, "invalid op_id (method can not be called for spill moves)");
4157
4158 if (_split_children.length() == 0) {
4159 // simple case if interval was not split
4160 return covers(op_id, mode);
4161
4162 } else {
4163 // extended case: check all split children
4164 int len = _split_children.length();
4165 for (int i = 0; i < len; i++) {
4166 Interval* cur = _split_children.at(i);
4167 if (cur->covers(op_id, mode)) {
4168 return true;
4169 }
4170 }
4171 return false;
4172 }
4173 }
4174
4175
4176 // Note: use positions are sorted descending -> first use has highest index
4177 int Interval::first_usage(IntervalUseKind min_use_kind) const {
4178 assert(LinearScan::is_virtual_interval(this), "cannot access use positions for fixed intervals");
4179
4180 for (int i = _use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
4181 if (_use_pos_and_kinds.at(i + 1) >= min_use_kind) {
4182 return _use_pos_and_kinds.at(i);
4183 }
4184 }
4185 return max_jint;
4186 }
4187
4188 int Interval::next_usage(IntervalUseKind min_use_kind, int from) const {
4189 assert(LinearScan::is_virtual_interval(this), "cannot access use positions for fixed intervals");
4190
4191 for (int i = _use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
4192 if (_use_pos_and_kinds.at(i) >= from && _use_pos_and_kinds.at(i + 1) >= min_use_kind) {
4193 return _use_pos_and_kinds.at(i);
4194 }
4195 }
4196 return max_jint;
4197 }
4198
4199 int Interval::next_usage_exact(IntervalUseKind exact_use_kind, int from) const {
4200 assert(LinearScan::is_virtual_interval(this), "cannot access use positions for fixed intervals");
4201
4202 for (int i = _use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
4203 if (_use_pos_and_kinds.at(i) >= from && _use_pos_and_kinds.at(i + 1) == exact_use_kind) {
4204 return _use_pos_and_kinds.at(i);
4205 }
4206 }
4207 return max_jint;
4208 }
4209
4210 int Interval::previous_usage(IntervalUseKind min_use_kind, int from) const {
4211 assert(LinearScan::is_virtual_interval(this), "cannot access use positions for fixed intervals");
4212
4213 int prev = 0;
4214 for (int i = _use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
4215 if (_use_pos_and_kinds.at(i) > from) {
4216 return prev;
4217 }
4218 if (_use_pos_and_kinds.at(i + 1) >= min_use_kind) {
4219 prev = _use_pos_and_kinds.at(i);
4220 }
4221 }
4222 return prev;
4223 }
4224
4225 void Interval::add_use_pos(int pos, IntervalUseKind use_kind) {
4226 assert(covers(pos, LIR_OpVisitState::inputMode), "use position not covered by live range");
4227
4228 // do not add use positions for precolored intervals because
4229 // they are never used
4230 if (use_kind != noUse && reg_num() >= LIR_OprDesc::vreg_base) {
4231 #ifdef ASSERT
4232 assert(_use_pos_and_kinds.length() % 2 == 0, "must be");
4233 for (int i = 0; i < _use_pos_and_kinds.length(); i += 2) {
4234 assert(pos <= _use_pos_and_kinds.at(i), "already added a use-position with lower position");
4235 assert(_use_pos_and_kinds.at(i + 1) >= firstValidKind && _use_pos_and_kinds.at(i + 1) <= lastValidKind, "invalid use kind");
4236 if (i > 0) {
4237 assert(_use_pos_and_kinds.at(i) < _use_pos_and_kinds.at(i - 2), "not sorted descending");
4238 }
4239 }
4240 #endif
4241
4242 // Note: add_use is called in descending order, so list gets sorted
4243 // automatically by just appending new use positions
4244 int len = _use_pos_and_kinds.length();
4245 if (len == 0 || _use_pos_and_kinds.at(len - 2) > pos) {
4246 _use_pos_and_kinds.append(pos);
4247 _use_pos_and_kinds.append(use_kind);
4248 } else if (_use_pos_and_kinds.at(len - 1) < use_kind) {
4249 assert(_use_pos_and_kinds.at(len - 2) == pos, "list not sorted correctly");
4250 _use_pos_and_kinds.at_put(len - 1, use_kind);
4251 }
4252 }
4253 }
4254
4255 void Interval::add_range(int from, int to) {
4256 assert(from < to, "invalid range");
4257 assert(first() == Range::end() || to < first()->next()->from(), "not inserting at begin of interval");
4258 assert(from <= first()->to(), "not inserting at begin of interval");
4259
4260 if (first()->from() <= to) {
4261 // join intersecting ranges
4262 first()->set_from(MIN2(from, first()->from()));
4263 first()->set_to (MAX2(to, first()->to()));
4264 } else {
4265 // insert new range
4266 _first = new Range(from, to, first());
4267 }
4268 }
4269
4270 Interval* Interval::new_split_child() {
4271 // allocate new interval
4272 Interval* result = new Interval(-1);
4273 result->set_type(type());
4274
4275 Interval* parent = split_parent();
4276 result->_split_parent = parent;
4277 result->set_register_hint(parent);
4278
4279 // insert new interval in children-list of parent
4280 if (parent->_split_children.length() == 0) {
4281 assert(is_split_parent(), "list must be initialized at first split");
4282
4283 parent->_split_children = IntervalList(4);
4284 parent->_split_children.append(this);
4285 }
4286 parent->_split_children.append(result);
4287
4288 return result;
4289 }
4290
4291 // split this interval at the specified position and return
4292 // the remainder as a new interval.
4293 //
4294 // when an interval is split, a bi-directional link is established between the original interval
4295 // (the split parent) and the intervals that are split off this interval (the split children)
4296 // When a split child is split again, the new created interval is also a direct child
4297 // of the original parent (there is no tree of split children stored, but a flat list)
4298 // All split children are spilled to the same stack slot (stored in _canonical_spill_slot)
4299 //
4300 // Note: The new interval has no valid reg_num
4301 Interval* Interval::split(int split_pos) {
4302 assert(LinearScan::is_virtual_interval(this), "cannot split fixed intervals");
4303
4304 // allocate new interval
4305 Interval* result = new_split_child();
4306
4307 // split the ranges
4308 Range* prev = NULL;
4309 Range* cur = _first;
4310 while (cur != Range::end() && cur->to() <= split_pos) {
4311 prev = cur;
4312 cur = cur->next();
4313 }
4314 assert(cur != Range::end(), "split interval after end of last range");
4315
4316 if (cur->from() < split_pos) {
4317 result->_first = new Range(split_pos, cur->to(), cur->next());
4318 cur->set_to(split_pos);
4319 cur->set_next(Range::end());
4320
4321 } else {
4322 assert(prev != NULL, "split before start of first range");
4323 result->_first = cur;
4324 prev->set_next(Range::end());
4325 }
4326 result->_current = result->_first;
4327 _cached_to = -1; // clear cached value
4328
4329 // split list of use positions
4330 int total_len = _use_pos_and_kinds.length();
4331 int start_idx = total_len - 2;
4332 while (start_idx >= 0 && _use_pos_and_kinds.at(start_idx) < split_pos) {
4333 start_idx -= 2;
4334 }
4335
4336 intStack new_use_pos_and_kinds(total_len - start_idx);
4337 int i;
4338 for (i = start_idx + 2; i < total_len; i++) {
4339 new_use_pos_and_kinds.append(_use_pos_and_kinds.at(i));
4340 }
4341
4342 _use_pos_and_kinds.truncate(start_idx + 2);
4343 result->_use_pos_and_kinds = _use_pos_and_kinds;
4344 _use_pos_and_kinds = new_use_pos_and_kinds;
4345
4346 #ifdef ASSERT
4347 assert(_use_pos_and_kinds.length() % 2 == 0, "must have use kind for each use pos");
4348 assert(result->_use_pos_and_kinds.length() % 2 == 0, "must have use kind for each use pos");
4349 assert(_use_pos_and_kinds.length() + result->_use_pos_and_kinds.length() == total_len, "missed some entries");
4350
4351 for (i = 0; i < _use_pos_and_kinds.length(); i += 2) {
4352 assert(_use_pos_and_kinds.at(i) < split_pos, "must be");
4353 assert(_use_pos_and_kinds.at(i + 1) >= firstValidKind && _use_pos_and_kinds.at(i + 1) <= lastValidKind, "invalid use kind");
4354 }
4355 for (i = 0; i < result->_use_pos_and_kinds.length(); i += 2) {
4356 assert(result->_use_pos_and_kinds.at(i) >= split_pos, "must be");
4357 assert(result->_use_pos_and_kinds.at(i + 1) >= firstValidKind && result->_use_pos_and_kinds.at(i + 1) <= lastValidKind, "invalid use kind");
4358 }
4359 #endif
4360
4361 return result;
4362 }
4363
4364 // split this interval at the specified position and return
4365 // the head as a new interval (the original interval is the tail)
4366 //
4367 // Currently, only the first range can be split, and the new interval
4368 // must not have split positions
4369 Interval* Interval::split_from_start(int split_pos) {
4370 assert(LinearScan::is_virtual_interval(this), "cannot split fixed intervals");
4371 assert(split_pos > from() && split_pos < to(), "can only split inside interval");
4372 assert(split_pos > _first->from() && split_pos <= _first->to(), "can only split inside first range");
4373 assert(first_usage(noUse) > split_pos, "can not split when use positions are present");
4374
4375 // allocate new interval
4376 Interval* result = new_split_child();
4377
4378 // the new created interval has only one range (checked by assertion above),
4379 // so the splitting of the ranges is very simple
4380 result->add_range(_first->from(), split_pos);
4381
4382 if (split_pos == _first->to()) {
4383 assert(_first->next() != Range::end(), "must not be at end");
4384 _first = _first->next();
4385 } else {
4386 _first->set_from(split_pos);
4387 }
4388
4389 return result;
4390 }
4391
4392
4393 // returns true if the op_id is inside the interval
4394 bool Interval::covers(int op_id, LIR_OpVisitState::OprMode mode) const {
4395 Range* cur = _first;
4396
4397 while (cur != Range::end() && cur->to() < op_id) {
4398 cur = cur->next();
4399 }
4400 if (cur != Range::end()) {
4401 assert(cur->to() != cur->next()->from(), "ranges not separated");
4402
4403 if (mode == LIR_OpVisitState::outputMode) {
4404 return cur->from() <= op_id && op_id < cur->to();
4405 } else {
4406 return cur->from() <= op_id && op_id <= cur->to();
4407 }
4408 }
4409 return false;
4410 }
4411
4412 // returns true if the interval has any hole between hole_from and hole_to
4413 // (even if the hole has only the length 1)
4414 bool Interval::has_hole_between(int hole_from, int hole_to) {
4415 assert(hole_from < hole_to, "check");
4416 assert(from() <= hole_from && hole_to <= to(), "index out of interval");
4417
4418 Range* cur = _first;
4419 while (cur != Range::end()) {
4420 assert(cur->to() < cur->next()->from(), "no space between ranges");
4421
4422 // hole-range starts before this range -> hole
4423 if (hole_from < cur->from()) {
4424 return true;
4425
4426 // hole-range completely inside this range -> no hole
4427 } else if (hole_to <= cur->to()) {
4428 return false;
4429
4430 // overlapping of hole-range with this range -> hole
4431 } else if (hole_from <= cur->to()) {
4432 return true;
4433 }
4434
4435 cur = cur->next();
4436 }
4437
4438 return false;
4439 }
4440
4441
4442 #ifndef PRODUCT
4443 void Interval::print(outputStream* out) const {
4444 const char* SpillState2Name[] = { "no definition", "no spill store", "one spill store", "store at definition", "start in memory", "no optimization" };
4445 const char* UseKind2Name[] = { "N", "L", "S", "M" };
4446
4447 const char* type_name;
4448 LIR_Opr opr = LIR_OprFact::illegal();
4449 if (reg_num() < LIR_OprDesc::vreg_base) {
4450 type_name = "fixed";
4451 // need a temporary operand for fixed intervals because type() cannot be called
4452 if (assigned_reg() >= pd_first_cpu_reg && assigned_reg() <= pd_last_cpu_reg) {
4453 opr = LIR_OprFact::single_cpu(assigned_reg());
4454 } else if (assigned_reg() >= pd_first_fpu_reg && assigned_reg() <= pd_last_fpu_reg) {
4455 opr = LIR_OprFact::single_fpu(assigned_reg() - pd_first_fpu_reg);
4456 #ifdef X86
4457 } else if (assigned_reg() >= pd_first_xmm_reg && assigned_reg() <= pd_last_xmm_reg) {
4458 opr = LIR_OprFact::single_xmm(assigned_reg() - pd_first_xmm_reg);
4459 #endif
4460 } else {
4461 ShouldNotReachHere();
4462 }
4463 } else {
4464 type_name = type2name(type());
4465 if (assigned_reg() != -1) {
4466 opr = LinearScan::calc_operand_for_interval(this);
4467 }
4468 }
4469
4470 out->print("%d %s ", reg_num(), type_name);
4471 if (opr->is_valid()) {
4472 out->print("\"");
4473 opr->print(out);
4474 out->print("\" ");
4475 }
4476 out->print("%d %d ", split_parent()->reg_num(), (register_hint(false) != NULL ? register_hint(false)->reg_num() : -1));
4477
4478 // print ranges
4479 Range* cur = _first;
4480 while (cur != Range::end()) {
4481 cur->print(out);
4482 cur = cur->next();
4483 assert(cur != NULL, "range list not closed with range sentinel");
4484 }
4485
4486 // print use positions
4487 int prev = 0;
4488 assert(_use_pos_and_kinds.length() % 2 == 0, "must be");
4489 for (int i =_use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
4490 assert(_use_pos_and_kinds.at(i + 1) >= firstValidKind && _use_pos_and_kinds.at(i + 1) <= lastValidKind, "invalid use kind");
4491 assert(prev < _use_pos_and_kinds.at(i), "use positions not sorted");
4492
4493 out->print("%d %s ", _use_pos_and_kinds.at(i), UseKind2Name[_use_pos_and_kinds.at(i + 1)]);
4494 prev = _use_pos_and_kinds.at(i);
4495 }
4496
4497 out->print(" \"%s\"", SpillState2Name[spill_state()]);
4498 out->cr();
4499 }
4500 #endif
4501
4502
4503
4504 // **** Implementation of IntervalWalker ****************************
4505
4506 IntervalWalker::IntervalWalker(LinearScan* allocator, Interval* unhandled_fixed_first, Interval* unhandled_any_first)
4507 : _compilation(allocator->compilation())
4508 , _allocator(allocator)
4509 {
4510 _unhandled_first[fixedKind] = unhandled_fixed_first;
4511 _unhandled_first[anyKind] = unhandled_any_first;
4512 _active_first[fixedKind] = Interval::end();
4513 _inactive_first[fixedKind] = Interval::end();
4514 _active_first[anyKind] = Interval::end();
4515 _inactive_first[anyKind] = Interval::end();
4516 _current_position = -1;
4517 _current = NULL;
4518 next_interval();
4519 }
4520
4521
4522 // append interval at top of list
4523 void IntervalWalker::append_unsorted(Interval** list, Interval* interval) {
4524 interval->set_next(*list); *list = interval;
4525 }
4526
4527
4528 // append interval in order of current range from()
4529 void IntervalWalker::append_sorted(Interval** list, Interval* interval) {
4530 Interval* prev = NULL;
4531 Interval* cur = *list;
4532 while (cur->current_from() < interval->current_from()) {
4533 prev = cur; cur = cur->next();
4534 }
4535 if (prev == NULL) {
4536 *list = interval;
4537 } else {
4538 prev->set_next(interval);
4539 }
4540 interval->set_next(cur);
4541 }
4542
4543 void IntervalWalker::append_to_unhandled(Interval** list, Interval* interval) {
4544 assert(interval->from() >= current()->current_from(), "cannot append new interval before current walk position");
4545
4546 Interval* prev = NULL;
4547 Interval* cur = *list;
4548 while (cur->from() < interval->from() || (cur->from() == interval->from() && cur->first_usage(noUse) < interval->first_usage(noUse))) {
4549 prev = cur; cur = cur->next();
4550 }
4551 if (prev == NULL) {
4552 *list = interval;
4553 } else {
4554 prev->set_next(interval);
4555 }
4556 interval->set_next(cur);
4557 }
4558
4559
4560 inline bool IntervalWalker::remove_from_list(Interval** list, Interval* i) {
4561 while (*list != Interval::end() && *list != i) {
4562 list = (*list)->next_addr();
4563 }
4564 if (*list != Interval::end()) {
4565 assert(*list == i, "check");
4566 *list = (*list)->next();
4567 return true;
4568 } else {
4569 return false;
4570 }
4571 }
4572
4573 void IntervalWalker::remove_from_list(Interval* i) {
4574 bool deleted;
4575
4576 if (i->state() == activeState) {
4577 deleted = remove_from_list(active_first_addr(anyKind), i);
4578 } else {
4579 assert(i->state() == inactiveState, "invalid state");
4580 deleted = remove_from_list(inactive_first_addr(anyKind), i);
4581 }
4582
4583 assert(deleted, "interval has not been found in list");
4584 }
4585
4586
4587 void IntervalWalker::walk_to(IntervalState state, int from) {
4588 assert (state == activeState || state == inactiveState, "wrong state");
4589 for_each_interval_kind(kind) {
4590 Interval** prev = state == activeState ? active_first_addr(kind) : inactive_first_addr(kind);
4591 Interval* next = *prev;
4592 while (next->current_from() <= from) {
4593 Interval* cur = next;
4594 next = cur->next();
4595
4596 bool range_has_changed = false;
4597 while (cur->current_to() <= from) {
4598 cur->next_range();
4599 range_has_changed = true;
4600 }
4601
4602 // also handle move from inactive list to active list
4603 range_has_changed = range_has_changed || (state == inactiveState && cur->current_from() <= from);
4604
4605 if (range_has_changed) {
4606 // remove cur from list
4607 *prev = next;
4608 if (cur->current_at_end()) {
4609 // move to handled state (not maintained as a list)
4610 cur->set_state(handledState);
4611 interval_moved(cur, kind, state, handledState);
4612 } else if (cur->current_from() <= from){
4613 // sort into active list
4614 append_sorted(active_first_addr(kind), cur);
4615 cur->set_state(activeState);
4616 if (*prev == cur) {
4617 assert(state == activeState, "check");
4618 prev = cur->next_addr();
4619 }
4620 interval_moved(cur, kind, state, activeState);
4621 } else {
4622 // sort into inactive list
4623 append_sorted(inactive_first_addr(kind), cur);
4624 cur->set_state(inactiveState);
4625 if (*prev == cur) {
4626 assert(state == inactiveState, "check");
4627 prev = cur->next_addr();
4628 }
4629 interval_moved(cur, kind, state, inactiveState);
4630 }
4631 } else {
4632 prev = cur->next_addr();
4633 continue;
4634 }
4635 }
4636 }
4637 }
4638
4639
4640 void IntervalWalker::next_interval() {
4641 IntervalKind kind;
4642 Interval* any = _unhandled_first[anyKind];
4643 Interval* fixed = _unhandled_first[fixedKind];
4644
4645 if (any != Interval::end()) {
4646 // intervals may start at same position -> prefer fixed interval
4647 kind = fixed != Interval::end() && fixed->from() <= any->from() ? fixedKind : anyKind;
4648
4649 assert (kind == fixedKind && fixed->from() <= any->from() ||
4650 kind == anyKind && any->from() <= fixed->from(), "wrong interval!!!");
4651 assert(any == Interval::end() || fixed == Interval::end() || any->from() != fixed->from() || kind == fixedKind, "if fixed and any-Interval start at same position, fixed must be processed first");
4652
4653 } else if (fixed != Interval::end()) {
4654 kind = fixedKind;
4655 } else {
4656 _current = NULL; return;
4657 }
4658 _current_kind = kind;
4659 _current = _unhandled_first[kind];
4660 _unhandled_first[kind] = _current->next();
4661 _current->set_next(Interval::end());
4662 _current->rewind_range();
4663 }
4664
4665
4666 void IntervalWalker::walk_to(int lir_op_id) {
4667 assert(_current_position <= lir_op_id, "can not walk backwards");
4668 while (current() != NULL) {
4669 bool is_active = current()->from() <= lir_op_id;
4670 int id = is_active ? current()->from() : lir_op_id;
4671
4672 TRACE_LINEAR_SCAN(2, if (_current_position < id) { tty->cr(); tty->print_cr("walk_to(%d) **************************************************************", id); })
4673
4674 // set _current_position prior to call of walk_to
4675 _current_position = id;
4676
4677 // call walk_to even if _current_position == id
4678 walk_to(activeState, id);
4679 walk_to(inactiveState, id);
4680
4681 if (is_active) {
4682 current()->set_state(activeState);
4683 if (activate_current()) {
4684 append_sorted(active_first_addr(current_kind()), current());
4685 interval_moved(current(), current_kind(), unhandledState, activeState);
4686 }
4687
4688 next_interval();
4689 } else {
4690 return;
4691 }
4692 }
4693 }
4694
4695 void IntervalWalker::interval_moved(Interval* interval, IntervalKind kind, IntervalState from, IntervalState to) {
4696 #ifndef PRODUCT
4697 if (TraceLinearScanLevel >= 4) {
4698 #define print_state(state) \
4699 switch(state) {\
4700 case unhandledState: tty->print("unhandled"); break;\
4701 case activeState: tty->print("active"); break;\
4702 case inactiveState: tty->print("inactive"); break;\
4703 case handledState: tty->print("handled"); break;\
4704 default: ShouldNotReachHere(); \
4705 }
4706
4707 print_state(from); tty->print(" to "); print_state(to);
4708 tty->fill_to(23);
4709 interval->print();
4710
4711 #undef print_state
4712 }
4713 #endif
4714 }
4715
4716
4717
4718 // **** Implementation of LinearScanWalker **************************
4719
4720 LinearScanWalker::LinearScanWalker(LinearScan* allocator, Interval* unhandled_fixed_first, Interval* unhandled_any_first)
4721 : IntervalWalker(allocator, unhandled_fixed_first, unhandled_any_first)
4722 , _move_resolver(allocator)
4723 {
4724 for (int i = 0; i < LinearScan::nof_regs; i++) {
4725 _spill_intervals[i] = new IntervalList(2);
4726 }
4727 }
4728
4729
4730 inline void LinearScanWalker::init_use_lists(bool only_process_use_pos) {
4731 for (int i = _first_reg; i <= _last_reg; i++) {
4732 _use_pos[i] = max_jint;
4733
4734 if (!only_process_use_pos) {
4735 _block_pos[i] = max_jint;
4736 _spill_intervals[i]->clear();
4737 }
4738 }
4739 }
4740
4741 inline void LinearScanWalker::exclude_from_use(int reg) {
4742 assert(reg < LinearScan::nof_regs, "interval must have a register assigned (stack slots not allowed)");
4743 if (reg >= _first_reg && reg <= _last_reg) {
4744 _use_pos[reg] = 0;
4745 }
4746 }
4747 inline void LinearScanWalker::exclude_from_use(Interval* i) {
4748 assert(i->assigned_reg() != any_reg, "interval has no register assigned");
4749
4750 exclude_from_use(i->assigned_reg());
4751 exclude_from_use(i->assigned_regHi());
4752 }
4753
4754 inline void LinearScanWalker::set_use_pos(int reg, Interval* i, int use_pos, bool only_process_use_pos) {
4755 assert(use_pos != 0, "must use exclude_from_use to set use_pos to 0");
4756
4757 if (reg >= _first_reg && reg <= _last_reg) {
4758 if (_use_pos[reg] > use_pos) {
4759 _use_pos[reg] = use_pos;
4760 }
4761 if (!only_process_use_pos) {
4762 _spill_intervals[reg]->append(i);
4763 }
4764 }
4765 }
4766 inline void LinearScanWalker::set_use_pos(Interval* i, int use_pos, bool only_process_use_pos) {
4767 assert(i->assigned_reg() != any_reg, "interval has no register assigned");
4768 if (use_pos != -1) {
4769 set_use_pos(i->assigned_reg(), i, use_pos, only_process_use_pos);
4770 set_use_pos(i->assigned_regHi(), i, use_pos, only_process_use_pos);
4771 }
4772 }
4773
4774 inline void LinearScanWalker::set_block_pos(int reg, Interval* i, int block_pos) {
4775 if (reg >= _first_reg && reg <= _last_reg) {
4776 if (_block_pos[reg] > block_pos) {
4777 _block_pos[reg] = block_pos;
4778 }
4779 if (_use_pos[reg] > block_pos) {
4780 _use_pos[reg] = block_pos;
4781 }
4782 }
4783 }
4784 inline void LinearScanWalker::set_block_pos(Interval* i, int block_pos) {
4785 assert(i->assigned_reg() != any_reg, "interval has no register assigned");
4786 if (block_pos != -1) {
4787 set_block_pos(i->assigned_reg(), i, block_pos);
4788 set_block_pos(i->assigned_regHi(), i, block_pos);
4789 }
4790 }
4791
4792
4793 void LinearScanWalker::free_exclude_active_fixed() {
4794 Interval* list = active_first(fixedKind);
4795 while (list != Interval::end()) {
4796 assert(list->assigned_reg() < LinearScan::nof_regs, "active interval must have a register assigned");
4797 exclude_from_use(list);
4798 list = list->next();
4799 }
4800 }
4801
4802 void LinearScanWalker::free_exclude_active_any() {
4803 Interval* list = active_first(anyKind);
4804 while (list != Interval::end()) {
4805 exclude_from_use(list);
4806 list = list->next();
4807 }
4808 }
4809
4810 void LinearScanWalker::free_collect_inactive_fixed(Interval* cur) {
4811 Interval* list = inactive_first(fixedKind);
4812 while (list != Interval::end()) {
4813 if (cur->to() <= list->current_from()) {
4814 assert(list->current_intersects_at(cur) == -1, "must not intersect");
4815 set_use_pos(list, list->current_from(), true);
4816 } else {
4817 set_use_pos(list, list->current_intersects_at(cur), true);
4818 }
4819 list = list->next();
4820 }
4821 }
4822
4823 void LinearScanWalker::free_collect_inactive_any(Interval* cur) {
4824 Interval* list = inactive_first(anyKind);
4825 while (list != Interval::end()) {
4826 set_use_pos(list, list->current_intersects_at(cur), true);
4827 list = list->next();
4828 }
4829 }
4830
4831 void LinearScanWalker::free_collect_unhandled(IntervalKind kind, Interval* cur) {
4832 Interval* list = unhandled_first(kind);
4833 while (list != Interval::end()) {
4834 set_use_pos(list, list->intersects_at(cur), true);
4835 if (kind == fixedKind && cur->to() <= list->from()) {
4836 set_use_pos(list, list->from(), true);
4837 }
4838 list = list->next();
4839 }
4840 }
4841
4842 void LinearScanWalker::spill_exclude_active_fixed() {
4843 Interval* list = active_first(fixedKind);
4844 while (list != Interval::end()) {
4845 exclude_from_use(list);
4846 list = list->next();
4847 }
4848 }
4849
4850 void LinearScanWalker::spill_block_unhandled_fixed(Interval* cur) {
4851 Interval* list = unhandled_first(fixedKind);
4852 while (list != Interval::end()) {
4853 set_block_pos(list, list->intersects_at(cur));
4854 list = list->next();
4855 }
4856 }
4857
4858 void LinearScanWalker::spill_block_inactive_fixed(Interval* cur) {
4859 Interval* list = inactive_first(fixedKind);
4860 while (list != Interval::end()) {
4861 if (cur->to() > list->current_from()) {
4862 set_block_pos(list, list->current_intersects_at(cur));
4863 } else {
4864 assert(list->current_intersects_at(cur) == -1, "invalid optimization: intervals intersect");
4865 }
4866
4867 list = list->next();
4868 }
4869 }
4870
4871 void LinearScanWalker::spill_collect_active_any() {
4872 Interval* list = active_first(anyKind);
4873 while (list != Interval::end()) {
4874 set_use_pos(list, MIN2(list->next_usage(loopEndMarker, _current_position), list->to()), false);
4875 list = list->next();
4876 }
4877 }
4878
4879 void LinearScanWalker::spill_collect_inactive_any(Interval* cur) {
4880 Interval* list = inactive_first(anyKind);
4881 while (list != Interval::end()) {
4882 if (list->current_intersects(cur)) {
4883 set_use_pos(list, MIN2(list->next_usage(loopEndMarker, _current_position), list->to()), false);
4884 }
4885 list = list->next();
4886 }
4887 }
4888
4889
4890 void LinearScanWalker::insert_move(int op_id, Interval* src_it, Interval* dst_it) {
4891 // output all moves here. When source and target are equal, the move is
4892 // optimized away later in assign_reg_nums
4893
4894 op_id = (op_id + 1) & ~1;
4895 BlockBegin* op_block = allocator()->block_of_op_with_id(op_id);
4896 assert(op_id > 0 && allocator()->block_of_op_with_id(op_id - 2) == op_block, "cannot insert move at block boundary");
4897
4898 // calculate index of instruction inside instruction list of current block
4899 // the minimal index (for a block with no spill moves) can be calculated because the
4900 // numbering of instructions is known.
4901 // When the block already contains spill moves, the index must be increased until the
4902 // correct index is reached.
4903 LIR_OpList* list = op_block->lir()->instructions_list();
4904 int index = (op_id - list->at(0)->id()) / 2;
4905 assert(list->at(index)->id() <= op_id, "error in calculation");
4906
4907 while (list->at(index)->id() != op_id) {
4908 index++;
4909 assert(0 <= index && index < list->length(), "index out of bounds");
4910 }
4911 assert(1 <= index && index < list->length(), "index out of bounds");
4912 assert(list->at(index)->id() == op_id, "error in calculation");
4913
4914 // insert new instruction before instruction at position index
4915 _move_resolver.move_insert_position(op_block->lir(), index - 1);
4916 _move_resolver.add_mapping(src_it, dst_it);
4917 }
4918
4919
4920 int LinearScanWalker::find_optimal_split_pos(BlockBegin* min_block, BlockBegin* max_block, int max_split_pos) {
4921 int from_block_nr = min_block->linear_scan_number();
4922 int to_block_nr = max_block->linear_scan_number();
4923
4924 assert(0 <= from_block_nr && from_block_nr < block_count(), "out of range");
4925 assert(0 <= to_block_nr && to_block_nr < block_count(), "out of range");
4926 assert(from_block_nr < to_block_nr, "must cross block boundary");
4927
4928 // Try to split at end of max_block. If this would be after
4929 // max_split_pos, then use the begin of max_block
4930 int optimal_split_pos = max_block->last_lir_instruction_id() + 2;
4931 if (optimal_split_pos > max_split_pos) {
4932 optimal_split_pos = max_block->first_lir_instruction_id();
4933 }
4934
4935 int min_loop_depth = max_block->loop_depth();
4936 for (int i = to_block_nr - 1; i >= from_block_nr; i--) {
4937 BlockBegin* cur = block_at(i);
4938
4939 if (cur->loop_depth() < min_loop_depth) {
4940 // block with lower loop-depth found -> split at the end of this block
4941 min_loop_depth = cur->loop_depth();
4942 optimal_split_pos = cur->last_lir_instruction_id() + 2;
4943 }
4944 }
4945 assert(optimal_split_pos > allocator()->max_lir_op_id() || allocator()->is_block_begin(optimal_split_pos), "algorithm must move split pos to block boundary");
4946
4947 return optimal_split_pos;
4948 }
4949
4950
4951 int LinearScanWalker::find_optimal_split_pos(Interval* it, int min_split_pos, int max_split_pos, bool do_loop_optimization) {
4952 int optimal_split_pos = -1;
4953 if (min_split_pos == max_split_pos) {
4954 // trivial case, no optimization of split position possible
4955 TRACE_LINEAR_SCAN(4, tty->print_cr(" min-pos and max-pos are equal, no optimization possible"));
4956 optimal_split_pos = min_split_pos;
4957
4958 } else {
4959 assert(min_split_pos < max_split_pos, "must be true then");
4960 assert(min_split_pos > 0, "cannot access min_split_pos - 1 otherwise");
4961
4962 // reason for using min_split_pos - 1: when the minimal split pos is exactly at the
4963 // beginning of a block, then min_split_pos is also a possible split position.
4964 // Use the block before as min_block, because then min_block->last_lir_instruction_id() + 2 == min_split_pos
4965 BlockBegin* min_block = allocator()->block_of_op_with_id(min_split_pos - 1);
4966
4967 // reason for using max_split_pos - 1: otherwise there would be an assertion failure
4968 // when an interval ends at the end of the last block of the method
4969 // (in this case, max_split_pos == allocator()->max_lir_op_id() + 2, and there is no
4970 // block at this op_id)
4971 BlockBegin* max_block = allocator()->block_of_op_with_id(max_split_pos - 1);
4972
4973 assert(min_block->linear_scan_number() <= max_block->linear_scan_number(), "invalid order");
4974 if (min_block == max_block) {
4975 // split position cannot be moved to block boundary, so split as late as possible
4976 TRACE_LINEAR_SCAN(4, tty->print_cr(" cannot move split pos to block boundary because min_pos and max_pos are in same block"));
4977 optimal_split_pos = max_split_pos;
4978
4979 } else if (it->has_hole_between(max_split_pos - 1, max_split_pos) && !allocator()->is_block_begin(max_split_pos)) {
4980 // Do not move split position if the interval has a hole before max_split_pos.
4981 // Intervals resulting from Phi-Functions have more than one definition (marked
4982 // as mustHaveRegister) with a hole before each definition. When the register is needed
4983 // for the second definition, an earlier reloading is unnecessary.
4984 TRACE_LINEAR_SCAN(4, tty->print_cr(" interval has hole just before max_split_pos, so splitting at max_split_pos"));
4985 optimal_split_pos = max_split_pos;
4986
4987 } else {
4988 // seach optimal block boundary between min_split_pos and max_split_pos
4989 TRACE_LINEAR_SCAN(4, tty->print_cr(" moving split pos to optimal block boundary between block B%d and B%d", min_block->block_id(), max_block->block_id()));
4990
4991 if (do_loop_optimization) {
4992 // Loop optimization: if a loop-end marker is found between min- and max-position,
4993 // then split before this loop
4994 int loop_end_pos = it->next_usage_exact(loopEndMarker, min_block->last_lir_instruction_id() + 2);
4995 TRACE_LINEAR_SCAN(4, tty->print_cr(" loop optimization: loop end found at pos %d", loop_end_pos));
4996
4997 assert(loop_end_pos > min_split_pos, "invalid order");
4998 if (loop_end_pos < max_split_pos) {
4999 // loop-end marker found between min- and max-position
5000 // if it is not the end marker for the same loop as the min-position, then move
5001 // the max-position to this loop block.
5002 // Desired result: uses tagged as shouldHaveRegister inside a loop cause a reloading
5003 // of the interval (normally, only mustHaveRegister causes a reloading)
5004 BlockBegin* loop_block = allocator()->block_of_op_with_id(loop_end_pos);
5005
5006 TRACE_LINEAR_SCAN(4, tty->print_cr(" interval is used in loop that ends in block B%d, so trying to move max_block back from B%d to B%d", loop_block->block_id(), max_block->block_id(), loop_block->block_id()));
5007 assert(loop_block != min_block, "loop_block and min_block must be different because block boundary is needed between");
5008
5009 optimal_split_pos = find_optimal_split_pos(min_block, loop_block, loop_block->last_lir_instruction_id() + 2);
5010 if (optimal_split_pos == loop_block->last_lir_instruction_id() + 2) {
5011 optimal_split_pos = -1;
5012 TRACE_LINEAR_SCAN(4, tty->print_cr(" loop optimization not necessary"));
5013 } else {
5014 TRACE_LINEAR_SCAN(4, tty->print_cr(" loop optimization successful"));
5015 }
5016 }
5017 }
5018
5019 if (optimal_split_pos == -1) {
5020 // not calculated by loop optimization
5021 optimal_split_pos = find_optimal_split_pos(min_block, max_block, max_split_pos);
5022 }
5023 }
5024 }
5025 TRACE_LINEAR_SCAN(4, tty->print_cr(" optimal split position: %d", optimal_split_pos));
5026
5027 return optimal_split_pos;
5028 }
5029
5030
5031 /*
5032 split an interval at the optimal position between min_split_pos and
5033 max_split_pos in two parts:
5034 1) the left part has already a location assigned
5035 2) the right part is sorted into to the unhandled-list
5036 */
5037 void LinearScanWalker::split_before_usage(Interval* it, int min_split_pos, int max_split_pos) {
5038 TRACE_LINEAR_SCAN(2, tty->print ("----- splitting interval: "); it->print());
5039 TRACE_LINEAR_SCAN(2, tty->print_cr(" between %d and %d", min_split_pos, max_split_pos));
5040
5041 assert(it->from() < min_split_pos, "cannot split at start of interval");
5042 assert(current_position() < min_split_pos, "cannot split before current position");
5043 assert(min_split_pos <= max_split_pos, "invalid order");
5044 assert(max_split_pos <= it->to(), "cannot split after end of interval");
5045
5046 int optimal_split_pos = find_optimal_split_pos(it, min_split_pos, max_split_pos, true);
5047
5048 assert(min_split_pos <= optimal_split_pos && optimal_split_pos <= max_split_pos, "out of range");
5049 assert(optimal_split_pos <= it->to(), "cannot split after end of interval");
5050 assert(optimal_split_pos > it->from(), "cannot split at start of interval");
5051
5052 if (optimal_split_pos == it->to() && it->next_usage(mustHaveRegister, min_split_pos) == max_jint) {
5053 // the split position would be just before the end of the interval
5054 // -> no split at all necessary
5055 TRACE_LINEAR_SCAN(4, tty->print_cr(" no split necessary because optimal split position is at end of interval"));
5056 return;
5057 }
5058
5059 // must calculate this before the actual split is performed and before split position is moved to odd op_id
5060 bool move_necessary = !allocator()->is_block_begin(optimal_split_pos) && !it->has_hole_between(optimal_split_pos - 1, optimal_split_pos);
5061
5062 if (!allocator()->is_block_begin(optimal_split_pos)) {
5063 // move position before actual instruction (odd op_id)
5064 optimal_split_pos = (optimal_split_pos - 1) | 1;
5065 }
5066
5067 TRACE_LINEAR_SCAN(4, tty->print_cr(" splitting at position %d", optimal_split_pos));
5068 assert(allocator()->is_block_begin(optimal_split_pos) || (optimal_split_pos % 2 == 1), "split pos must be odd when not on block boundary");
5069 assert(!allocator()->is_block_begin(optimal_split_pos) || (optimal_split_pos % 2 == 0), "split pos must be even on block boundary");
5070
5071 Interval* split_part = it->split(optimal_split_pos);
5072
5073 allocator()->append_interval(split_part);
5074 allocator()->copy_register_flags(it, split_part);
5075 split_part->set_insert_move_when_activated(move_necessary);
5076 append_to_unhandled(unhandled_first_addr(anyKind), split_part);
5077
5078 TRACE_LINEAR_SCAN(2, tty->print_cr(" split interval in two parts (insert_move_when_activated: %d)", move_necessary));
5079 TRACE_LINEAR_SCAN(2, tty->print (" "); it->print());
5080 TRACE_LINEAR_SCAN(2, tty->print (" "); split_part->print());
5081 }
5082
5083 /*
5084 split an interval at the optimal position between min_split_pos and
5085 max_split_pos in two parts:
5086 1) the left part has already a location assigned
5087 2) the right part is always on the stack and therefore ignored in further processing
5088 */
5089 void LinearScanWalker::split_for_spilling(Interval* it) {
5090 // calculate allowed range of splitting position
5091 int max_split_pos = current_position();
5092 int min_split_pos = MAX2(it->previous_usage(shouldHaveRegister, max_split_pos) + 1, it->from());
5093
5094 TRACE_LINEAR_SCAN(2, tty->print ("----- splitting and spilling interval: "); it->print());
5095 TRACE_LINEAR_SCAN(2, tty->print_cr(" between %d and %d", min_split_pos, max_split_pos));
5096
5097 assert(it->state() == activeState, "why spill interval that is not active?");
5098 assert(it->from() <= min_split_pos, "cannot split before start of interval");
5099 assert(min_split_pos <= max_split_pos, "invalid order");
5100 assert(max_split_pos < it->to(), "cannot split at end end of interval");
5101 assert(current_position() < it->to(), "interval must not end before current position");
5102
5103 if (min_split_pos == it->from()) {
5104 // the whole interval is never used, so spill it entirely to memory
5105 TRACE_LINEAR_SCAN(2, tty->print_cr(" spilling entire interval because split pos is at beginning of interval"));
5106 assert(it->first_usage(shouldHaveRegister) > current_position(), "interval must not have use position before current_position");
5107
5108 allocator()->assign_spill_slot(it);
5109 allocator()->change_spill_state(it, min_split_pos);
5110
5111 // Also kick parent intervals out of register to memory when they have no use
5112 // position. This avoids short interval in register surrounded by intervals in
5113 // memory -> avoid useless moves from memory to register and back
5114 Interval* parent = it;
5115 while (parent != NULL && parent->is_split_child()) {
5116 parent = parent->split_child_before_op_id(parent->from());
5117
5118 if (parent->assigned_reg() < LinearScan::nof_regs) {
5119 if (parent->first_usage(shouldHaveRegister) == max_jint) {
5120 // parent is never used, so kick it out of its assigned register
5121 TRACE_LINEAR_SCAN(4, tty->print_cr(" kicking out interval %d out of its register because it is never used", parent->reg_num()));
5122 allocator()->assign_spill_slot(parent);
5123 } else {
5124 // do not go further back because the register is actually used by the interval
5125 parent = NULL;
5126 }
5127 }
5128 }
5129
5130 } else {
5131 // search optimal split pos, split interval and spill only the right hand part
5132 int optimal_split_pos = find_optimal_split_pos(it, min_split_pos, max_split_pos, false);
5133
5134 assert(min_split_pos <= optimal_split_pos && optimal_split_pos <= max_split_pos, "out of range");
5135 assert(optimal_split_pos < it->to(), "cannot split at end of interval");
5136 assert(optimal_split_pos >= it->from(), "cannot split before start of interval");
5137
5138 if (!allocator()->is_block_begin(optimal_split_pos)) {
5139 // move position before actual instruction (odd op_id)
5140 optimal_split_pos = (optimal_split_pos - 1) | 1;
5141 }
5142
5143 TRACE_LINEAR_SCAN(4, tty->print_cr(" splitting at position %d", optimal_split_pos));
5144 assert(allocator()->is_block_begin(optimal_split_pos) || (optimal_split_pos % 2 == 1), "split pos must be odd when not on block boundary");
5145 assert(!allocator()->is_block_begin(optimal_split_pos) || (optimal_split_pos % 2 == 0), "split pos must be even on block boundary");
5146
5147 Interval* spilled_part = it->split(optimal_split_pos);
5148 allocator()->append_interval(spilled_part);
5149 allocator()->assign_spill_slot(spilled_part);
5150 allocator()->change_spill_state(spilled_part, optimal_split_pos);
5151
5152 if (!allocator()->is_block_begin(optimal_split_pos)) {
5153 TRACE_LINEAR_SCAN(4, tty->print_cr(" inserting move from interval %d to %d", it->reg_num(), spilled_part->reg_num()));
5154 insert_move(optimal_split_pos, it, spilled_part);
5155 }
5156
5157 // the current_split_child is needed later when moves are inserted for reloading
5158 assert(spilled_part->current_split_child() == it, "overwriting wrong current_split_child");
5159 spilled_part->make_current_split_child();
5160
5161 TRACE_LINEAR_SCAN(2, tty->print_cr(" split interval in two parts"));
5162 TRACE_LINEAR_SCAN(2, tty->print (" "); it->print());
5163 TRACE_LINEAR_SCAN(2, tty->print (" "); spilled_part->print());
5164 }
5165 }
5166
5167
5168 void LinearScanWalker::split_stack_interval(Interval* it) {
5169 int min_split_pos = current_position() + 1;
5170 int max_split_pos = MIN2(it->first_usage(shouldHaveRegister), it->to());
5171
5172 split_before_usage(it, min_split_pos, max_split_pos);
5173 }
5174
5175 void LinearScanWalker::split_when_partial_register_available(Interval* it, int register_available_until) {
5176 int min_split_pos = MAX2(it->previous_usage(shouldHaveRegister, register_available_until), it->from() + 1);
5177 int max_split_pos = register_available_until;
5178
5179 split_before_usage(it, min_split_pos, max_split_pos);
5180 }
5181
5182 void LinearScanWalker::split_and_spill_interval(Interval* it) {
5183 assert(it->state() == activeState || it->state() == inactiveState, "other states not allowed");
5184
5185 int current_pos = current_position();
5186 if (it->state() == inactiveState) {
5187 // the interval is currently inactive, so no spill slot is needed for now.
5188 // when the split part is activated, the interval has a new chance to get a register,
5189 // so in the best case no stack slot is necessary
5190 assert(it->has_hole_between(current_pos - 1, current_pos + 1), "interval can not be inactive otherwise");
5191 split_before_usage(it, current_pos + 1, current_pos + 1);
5192
5193 } else {
5194 // search the position where the interval must have a register and split
5195 // at the optimal position before.
5196 // The new created part is added to the unhandled list and will get a register
5197 // when it is activated
5198 int min_split_pos = current_pos + 1;
5199 int max_split_pos = MIN2(it->next_usage(mustHaveRegister, min_split_pos), it->to());
5200
5201 split_before_usage(it, min_split_pos, max_split_pos);
5202
5203 assert(it->next_usage(mustHaveRegister, current_pos) == max_jint, "the remaining part is spilled to stack and therefore has no register");
5204 split_for_spilling(it);
5205 }
5206 }
5207
5208
5209 int LinearScanWalker::find_free_reg(int reg_needed_until, int interval_to, int hint_reg, int ignore_reg, bool* need_split) {
5210 int min_full_reg = any_reg;
5211 int max_partial_reg = any_reg;
5212
5213 for (int i = _first_reg; i <= _last_reg; i++) {
5214 if (i == ignore_reg) {
5215 // this register must be ignored
5216
5217 } else if (_use_pos[i] >= interval_to) {
5218 // this register is free for the full interval
5219 if (min_full_reg == any_reg || i == hint_reg || (_use_pos[i] < _use_pos[min_full_reg] && min_full_reg != hint_reg)) {
5220 min_full_reg = i;
5221 }
5222 } else if (_use_pos[i] > reg_needed_until) {
5223 // this register is at least free until reg_needed_until
5224 if (max_partial_reg == any_reg || i == hint_reg || (_use_pos[i] > _use_pos[max_partial_reg] && max_partial_reg != hint_reg)) {
5225 max_partial_reg = i;
5226 }
5227 }
5228 }
5229
5230 if (min_full_reg != any_reg) {
5231 return min_full_reg;
5232 } else if (max_partial_reg != any_reg) {
5233 *need_split = true;
5234 return max_partial_reg;
5235 } else {
5236 return any_reg;
5237 }
5238 }
5239
5240 int LinearScanWalker::find_free_double_reg(int reg_needed_until, int interval_to, int hint_reg, bool* need_split) {
5241 assert((_last_reg - _first_reg + 1) % 2 == 0, "adjust algorithm");
5242
5243 int min_full_reg = any_reg;
5244 int max_partial_reg = any_reg;
5245
5246 for (int i = _first_reg; i < _last_reg; i+=2) {
5247 if (_use_pos[i] >= interval_to && _use_pos[i + 1] >= interval_to) {
5248 // this register is free for the full interval
5249 if (min_full_reg == any_reg || i == hint_reg || (_use_pos[i] < _use_pos[min_full_reg] && min_full_reg != hint_reg)) {
5250 min_full_reg = i;
5251 }
5252 } else if (_use_pos[i] > reg_needed_until && _use_pos[i + 1] > reg_needed_until) {
5253 // this register is at least free until reg_needed_until
5254 if (max_partial_reg == any_reg || i == hint_reg || (_use_pos[i] > _use_pos[max_partial_reg] && max_partial_reg != hint_reg)) {
5255 max_partial_reg = i;
5256 }
5257 }
5258 }
5259
5260 if (min_full_reg != any_reg) {
5261 return min_full_reg;
5262 } else if (max_partial_reg != any_reg) {
5263 *need_split = true;
5264 return max_partial_reg;
5265 } else {
5266 return any_reg;
5267 }
5268 }
5269
5270
5271 bool LinearScanWalker::alloc_free_reg(Interval* cur) {
5272 TRACE_LINEAR_SCAN(2, tty->print("trying to find free register for "); cur->print());
5273
5274 init_use_lists(true);
5275 free_exclude_active_fixed();
5276 free_exclude_active_any();
5277 free_collect_inactive_fixed(cur);
5278 free_collect_inactive_any(cur);
5279 // free_collect_unhandled(fixedKind, cur);
5280 assert(unhandled_first(fixedKind) == Interval::end(), "must not have unhandled fixed intervals because all fixed intervals have a use at position 0");
5281
5282 // _use_pos contains the start of the next interval that has this register assigned
5283 // (either as a fixed register or a normal allocated register in the past)
5284 // only intervals overlapping with cur are processed, non-overlapping invervals can be ignored safely
5285 TRACE_LINEAR_SCAN(4, tty->print_cr(" state of registers:"));
5286 TRACE_LINEAR_SCAN(4, for (int i = _first_reg; i <= _last_reg; i++) tty->print_cr(" reg %d: use_pos: %d", i, _use_pos[i]));
5287
5288 int hint_reg, hint_regHi;
5289 Interval* register_hint = cur->register_hint();
5290 if (register_hint != NULL) {
5291 hint_reg = register_hint->assigned_reg();
5292 hint_regHi = register_hint->assigned_regHi();
5293
5294 if (allocator()->is_precolored_cpu_interval(register_hint)) {
5295 assert(hint_reg != any_reg && hint_regHi == any_reg, "must be for fixed intervals");
5296 hint_regHi = hint_reg + 1; // connect e.g. eax-edx
5297 }
5298 TRACE_LINEAR_SCAN(4, tty->print(" hint registers %d, %d from interval ", hint_reg, hint_regHi); register_hint->print());
5299
5300 } else {
5301 hint_reg = any_reg;
5302 hint_regHi = any_reg;
5303 }
5304 assert(hint_reg == any_reg || hint_reg != hint_regHi, "hint reg and regHi equal");
5305 assert(cur->assigned_reg() == any_reg && cur->assigned_regHi() == any_reg, "register already assigned to interval");
5306
5307 // the register must be free at least until this position
5308 int reg_needed_until = cur->from() + 1;
5309 int interval_to = cur->to();
5310
5311 bool need_split = false;
5312 int split_pos = -1;
5313 int reg = any_reg;
5314 int regHi = any_reg;
5315
5316 if (_adjacent_regs) {
5317 reg = find_free_double_reg(reg_needed_until, interval_to, hint_reg, &need_split);
5318 regHi = reg + 1;
5319 if (reg == any_reg) {
5320 return false;
5321 }
5322 split_pos = MIN2(_use_pos[reg], _use_pos[regHi]);
5323
5324 } else {
5325 reg = find_free_reg(reg_needed_until, interval_to, hint_reg, any_reg, &need_split);
5326 if (reg == any_reg) {
5327 return false;
5328 }
5329 split_pos = _use_pos[reg];
5330
5331 if (_num_phys_regs == 2) {
5332 regHi = find_free_reg(reg_needed_until, interval_to, hint_regHi, reg, &need_split);
5333
5334 if (_use_pos[reg] < interval_to && regHi == any_reg) {
5335 // do not split interval if only one register can be assigned until the split pos
5336 // (when one register is found for the whole interval, split&spill is only
5337 // performed for the hi register)
5338 return false;
5339
5340 } else if (regHi != any_reg) {
5341 split_pos = MIN2(split_pos, _use_pos[regHi]);
5342
5343 // sort register numbers to prevent e.g. a move from eax,ebx to ebx,eax
5344 if (reg > regHi) {
5345 int temp = reg;
5346 reg = regHi;
5347 regHi = temp;
5348 }
5349 }
5350 }
5351 }
5352
5353 cur->assign_reg(reg, regHi);
5354 TRACE_LINEAR_SCAN(2, tty->print_cr("selected register %d, %d", reg, regHi));
5355
5356 assert(split_pos > 0, "invalid split_pos");
5357 if (need_split) {
5358 // register not available for full interval, so split it
5359 split_when_partial_register_available(cur, split_pos);
5360 }
5361
5362 // only return true if interval is completely assigned
5363 return _num_phys_regs == 1 || regHi != any_reg;
5364 }
5365
5366
5367 int LinearScanWalker::find_locked_reg(int reg_needed_until, int interval_to, int hint_reg, int ignore_reg, bool* need_split) {
5368 int max_reg = any_reg;
5369
5370 for (int i = _first_reg; i <= _last_reg; i++) {
5371 if (i == ignore_reg) {
5372 // this register must be ignored
5373
5374 } else if (_use_pos[i] > reg_needed_until) {
5375 if (max_reg == any_reg || i == hint_reg || (_use_pos[i] > _use_pos[max_reg] && max_reg != hint_reg)) {
5376 max_reg = i;
5377 }
5378 }
5379 }
5380
5381 if (max_reg != any_reg && _block_pos[max_reg] <= interval_to) {
5382 *need_split = true;
5383 }
5384
5385 return max_reg;
5386 }
5387
5388 int LinearScanWalker::find_locked_double_reg(int reg_needed_until, int interval_to, int hint_reg, bool* need_split) {
5389 assert((_last_reg - _first_reg + 1) % 2 == 0, "adjust algorithm");
5390
5391 int max_reg = any_reg;
5392
5393 for (int i = _first_reg; i < _last_reg; i+=2) {
5394 if (_use_pos[i] > reg_needed_until && _use_pos[i + 1] > reg_needed_until) {
5395 if (max_reg == any_reg || _use_pos[i] > _use_pos[max_reg]) {
5396 max_reg = i;
5397 }
5398 }
5399 }
5400
5401 if (_block_pos[max_reg] <= interval_to || _block_pos[max_reg + 1] <= interval_to) {
5402 *need_split = true;
5403 }
5404
5405 return max_reg;
5406 }
5407
5408 void LinearScanWalker::split_and_spill_intersecting_intervals(int reg, int regHi) {
5409 assert(reg != any_reg, "no register assigned");
5410
5411 for (int i = 0; i < _spill_intervals[reg]->length(); i++) {
5412 Interval* it = _spill_intervals[reg]->at(i);
5413 remove_from_list(it);
5414 split_and_spill_interval(it);
5415 }
5416
5417 if (regHi != any_reg) {
5418 IntervalList* processed = _spill_intervals[reg];
5419 for (int i = 0; i < _spill_intervals[regHi]->length(); i++) {
5420 Interval* it = _spill_intervals[regHi]->at(i);
5421 if (processed->index_of(it) == -1) {
5422 remove_from_list(it);
5423 split_and_spill_interval(it);
5424 }
5425 }
5426 }
5427 }
5428
5429
5430 // Split an Interval and spill it to memory so that cur can be placed in a register
5431 void LinearScanWalker::alloc_locked_reg(Interval* cur) {
5432 TRACE_LINEAR_SCAN(2, tty->print("need to split and spill to get register for "); cur->print());
5433
5434 // collect current usage of registers
5435 init_use_lists(false);
5436 spill_exclude_active_fixed();
5437 // spill_block_unhandled_fixed(cur);
5438 assert(unhandled_first(fixedKind) == Interval::end(), "must not have unhandled fixed intervals because all fixed intervals have a use at position 0");
5439 spill_block_inactive_fixed(cur);
5440 spill_collect_active_any();
5441 spill_collect_inactive_any(cur);
5442
5443 #ifndef PRODUCT
5444 if (TraceLinearScanLevel >= 4) {
5445 tty->print_cr(" state of registers:");
5446 for (int i = _first_reg; i <= _last_reg; i++) {
5447 tty->print(" reg %d: use_pos: %d, block_pos: %d, intervals: ", i, _use_pos[i], _block_pos[i]);
5448 for (int j = 0; j < _spill_intervals[i]->length(); j++) {
5449 tty->print("%d ", _spill_intervals[i]->at(j)->reg_num());
5450 }
5451 tty->cr();
5452 }
5453 }
5454 #endif
5455
5456 // the register must be free at least until this position
5457 int reg_needed_until = MIN2(cur->first_usage(mustHaveRegister), cur->from() + 1);
5458 int interval_to = cur->to();
5459 assert (reg_needed_until > 0 && reg_needed_until < max_jint, "interval has no use");
5460
5461 int split_pos = 0;
5462 int use_pos = 0;
5463 bool need_split = false;
5464 int reg, regHi;
5465
5466 if (_adjacent_regs) {
5467 reg = find_locked_double_reg(reg_needed_until, interval_to, any_reg, &need_split);
5468 regHi = reg + 1;
5469
5470 if (reg != any_reg) {
5471 use_pos = MIN2(_use_pos[reg], _use_pos[regHi]);
5472 split_pos = MIN2(_block_pos[reg], _block_pos[regHi]);
5473 }
5474 } else {
5475 reg = find_locked_reg(reg_needed_until, interval_to, any_reg, cur->assigned_reg(), &need_split);
5476 regHi = any_reg;
5477
5478 if (reg != any_reg) {
5479 use_pos = _use_pos[reg];
5480 split_pos = _block_pos[reg];
5481
5482 if (_num_phys_regs == 2) {
5483 if (cur->assigned_reg() != any_reg) {
5484 regHi = reg;
5485 reg = cur->assigned_reg();
5486 } else {
5487 regHi = find_locked_reg(reg_needed_until, interval_to, any_reg, reg, &need_split);
5488 if (regHi != any_reg) {
5489 use_pos = MIN2(use_pos, _use_pos[regHi]);
5490 split_pos = MIN2(split_pos, _block_pos[regHi]);
5491 }
5492 }
5493
5494 if (regHi != any_reg && reg > regHi) {
5495 // sort register numbers to prevent e.g. a move from eax,ebx to ebx,eax
5496 int temp = reg;
5497 reg = regHi;
5498 regHi = temp;
5499 }
5500 }
5501 }
5502 }
5503
5504 if (reg == any_reg || (_num_phys_regs == 2 && regHi == any_reg) || use_pos <= cur->first_usage(mustHaveRegister)) {
5505 // the first use of cur is later than the spilling position -> spill cur
5506 TRACE_LINEAR_SCAN(4, tty->print_cr("able to spill current interval. first_usage(register): %d, use_pos: %d", cur->first_usage(mustHaveRegister), use_pos));
5507
5508 if (cur->first_usage(mustHaveRegister) <= cur->from() + 1) {
5509 assert(false, "cannot spill interval that is used in first instruction (possible reason: no register found)");
5510 // assign a reasonable register and do a bailout in product mode to avoid errors
5511 allocator()->assign_spill_slot(cur);
5512 BAILOUT("LinearScan: no register found");
5513 }
5514
5515 split_and_spill_interval(cur);
5516 } else {
5517 TRACE_LINEAR_SCAN(4, tty->print_cr("decided to use register %d, %d", reg, regHi));
5518 assert(reg != any_reg && (_num_phys_regs == 1 || regHi != any_reg), "no register found");
5519 assert(split_pos > 0, "invalid split_pos");
5520 assert(need_split == false || split_pos > cur->from(), "splitting interval at from");
5521
5522 cur->assign_reg(reg, regHi);
5523 if (need_split) {
5524 // register not available for full interval, so split it
5525 split_when_partial_register_available(cur, split_pos);
5526 }
5527
5528 // perform splitting and spilling for all affected intervalls
5529 split_and_spill_intersecting_intervals(reg, regHi);
5530 }
5531 }
5532
5533 bool LinearScanWalker::no_allocation_possible(Interval* cur) {
5534 #ifdef X86
5535 // fast calculation of intervals that can never get a register because the
5536 // the next instruction is a call that blocks all registers
5537 // Note: this does not work if callee-saved registers are available (e.g. on Sparc)
5538
5539 // check if this interval is the result of a split operation
5540 // (an interval got a register until this position)
5541 int pos = cur->from();
5542 if ((pos & 1) == 1) {
5543 // the current instruction is a call that blocks all registers
5544 if (pos < allocator()->max_lir_op_id() && allocator()->has_call(pos + 1)) {
5545 TRACE_LINEAR_SCAN(4, tty->print_cr(" free register cannot be available because all registers blocked by following call"));
5546
5547 // safety check that there is really no register available
5548 assert(alloc_free_reg(cur) == false, "found a register for this interval");
5549 return true;
5550 }
5551
5552 }
5553 #endif
5554 return false;
5555 }
5556
5557 void LinearScanWalker::init_vars_for_alloc(Interval* cur) {
5558 BasicType type = cur->type();
5559 _num_phys_regs = LinearScan::num_physical_regs(type);
5560 _adjacent_regs = LinearScan::requires_adjacent_regs(type);
5561
5562 if (pd_init_regs_for_alloc(cur)) {
5563 // the appropriate register range was selected.
5564 } else if (type == T_FLOAT || type == T_DOUBLE) {
5565 _first_reg = pd_first_fpu_reg;
5566 _last_reg = pd_last_fpu_reg;
5567 } else {
5568 _first_reg = pd_first_cpu_reg;
5569 _last_reg = pd_last_cpu_reg;
5570 }
5571
5572 assert(0 <= _first_reg && _first_reg < LinearScan::nof_regs, "out of range");
5573 assert(0 <= _last_reg && _last_reg < LinearScan::nof_regs, "out of range");
5574 }
5575
5576
5577 bool LinearScanWalker::is_move(LIR_Op* op, Interval* from, Interval* to) {
5578 if (op->code() != lir_move) {
5579 return false;
5580 }
5581 assert(op->as_Op1() != NULL, "move must be LIR_Op1");
5582
5583 LIR_Opr in = ((LIR_Op1*)op)->in_opr();
5584 LIR_Opr res = ((LIR_Op1*)op)->result_opr();
5585 return in->is_virtual() && res->is_virtual() && in->vreg_number() == from->reg_num() && res->vreg_number() == to->reg_num();
5586 }
5587
5588 // optimization (especially for phi functions of nested loops):
5589 // assign same spill slot to non-intersecting intervals
5590 void LinearScanWalker::combine_spilled_intervals(Interval* cur) {
5591 if (cur->is_split_child()) {
5592 // optimization is only suitable for split parents
5593 return;
5594 }
5595
5596 Interval* register_hint = cur->register_hint(false);
5597 if (register_hint == NULL) {
5598 // cur is not the target of a move, otherwise register_hint would be set
5599 return;
5600 }
5601 assert(register_hint->is_split_parent(), "register hint must be split parent");
5602
5603 if (cur->spill_state() != noOptimization || register_hint->spill_state() != noOptimization) {
5604 // combining the stack slots for intervals where spill move optimization is applied
5605 // is not benefitial and would cause problems
5606 return;
5607 }
5608
5609 int begin_pos = cur->from();
5610 int end_pos = cur->to();
5611 if (end_pos > allocator()->max_lir_op_id() || (begin_pos & 1) != 0 || (end_pos & 1) != 0) {
5612 // safety check that lir_op_with_id is allowed
5613 return;
5614 }
5615
5616 if (!is_move(allocator()->lir_op_with_id(begin_pos), register_hint, cur) || !is_move(allocator()->lir_op_with_id(end_pos), cur, register_hint)) {
5617 // cur and register_hint are not connected with two moves
5618 return;
5619 }
5620
5621 Interval* begin_hint = register_hint->split_child_at_op_id(begin_pos, LIR_OpVisitState::inputMode);
5622 Interval* end_hint = register_hint->split_child_at_op_id(end_pos, LIR_OpVisitState::outputMode);
5623 if (begin_hint == end_hint || begin_hint->to() != begin_pos || end_hint->from() != end_pos) {
5624 // register_hint must be split, otherwise the re-writing of use positions does not work
5625 return;
5626 }
5627
5628 assert(begin_hint->assigned_reg() != any_reg, "must have register assigned");
5629 assert(end_hint->assigned_reg() == any_reg, "must not have register assigned");
5630 assert(cur->first_usage(mustHaveRegister) == begin_pos, "must have use position at begin of interval because of move");
5631 assert(end_hint->first_usage(mustHaveRegister) == end_pos, "must have use position at begin of interval because of move");
5632
5633 if (begin_hint->assigned_reg() < LinearScan::nof_regs) {
5634 // register_hint is not spilled at begin_pos, so it would not be benefitial to immediately spill cur
5635 return;
5636 }
5637 assert(register_hint->canonical_spill_slot() != -1, "must be set when part of interval was spilled");
5638
5639 // modify intervals such that cur gets the same stack slot as register_hint
5640 // delete use positions to prevent the intervals to get a register at beginning
5641 cur->set_canonical_spill_slot(register_hint->canonical_spill_slot());
5642 cur->remove_first_use_pos();
5643 end_hint->remove_first_use_pos();
5644 }
5645
5646
5647 // allocate a physical register or memory location to an interval
5648 bool LinearScanWalker::activate_current() {
5649 Interval* cur = current();
5650 bool result = true;
5651
5652 TRACE_LINEAR_SCAN(2, tty->print ("+++++ activating interval "); cur->print());
5653 TRACE_LINEAR_SCAN(4, tty->print_cr(" split_parent: %d, insert_move_when_activated: %d", cur->split_parent()->reg_num(), cur->insert_move_when_activated()));
5654
5655 if (cur->assigned_reg() >= LinearScan::nof_regs) {
5656 // activating an interval that has a stack slot assigned -> split it at first use position
5657 // used for method parameters
5658 TRACE_LINEAR_SCAN(4, tty->print_cr(" interval has spill slot assigned (method parameter) -> split it before first use"));
5659
5660 split_stack_interval(cur);
5661 result = false;
5662
5663 } else if (allocator()->gen()->is_vreg_flag_set(cur->reg_num(), LIRGenerator::must_start_in_memory)) {
5664 // activating an interval that must start in a stack slot, but may get a register later
5665 // used for lir_roundfp: rounding is done by store to stack and reload later
5666 TRACE_LINEAR_SCAN(4, tty->print_cr(" interval must start in stack slot -> split it before first use"));
5667 assert(cur->assigned_reg() == any_reg && cur->assigned_regHi() == any_reg, "register already assigned");
5668
5669 allocator()->assign_spill_slot(cur);
5670 split_stack_interval(cur);
5671 result = false;
5672
5673 } else if (cur->assigned_reg() == any_reg) {
5674 // interval has not assigned register -> normal allocation
5675 // (this is the normal case for most intervals)
5676 TRACE_LINEAR_SCAN(4, tty->print_cr(" normal allocation of register"));
5677
5678 // assign same spill slot to non-intersecting intervals
5679 combine_spilled_intervals(cur);
5680
5681 init_vars_for_alloc(cur);
5682 if (no_allocation_possible(cur) || !alloc_free_reg(cur)) {
5683 // no empty register available.
5684 // split and spill another interval so that this interval gets a register
5685 alloc_locked_reg(cur);
5686 }
5687
5688 // spilled intervals need not be move to active-list
5689 if (cur->assigned_reg() >= LinearScan::nof_regs) {
5690 result = false;
5691 }
5692 }
5693
5694 // load spilled values that become active from stack slot to register
5695 if (cur->insert_move_when_activated()) {
5696 assert(cur->is_split_child(), "must be");
5697 assert(cur->current_split_child() != NULL, "must be");
5698 assert(cur->current_split_child()->reg_num() != cur->reg_num(), "cannot insert move between same interval");
5699 TRACE_LINEAR_SCAN(4, tty->print_cr("Inserting move from interval %d to %d because insert_move_when_activated is set", cur->current_split_child()->reg_num(), cur->reg_num()));
5700
5701 insert_move(cur->from(), cur->current_split_child(), cur);
5702 }
5703 cur->make_current_split_child();
5704
5705 return result; // true = interval is moved to active list
5706 }
5707
5708
5709 // Implementation of EdgeMoveOptimizer
5710
5711 EdgeMoveOptimizer::EdgeMoveOptimizer() :
5712 _edge_instructions(4),
5713 _edge_instructions_idx(4)
5714 {
5715 }
5716
5717 void EdgeMoveOptimizer::optimize(BlockList* code) {
5718 EdgeMoveOptimizer optimizer = EdgeMoveOptimizer();
5719
5720 // ignore the first block in the list (index 0 is not processed)
5721 for (int i = code->length() - 1; i >= 1; i--) {
5722 BlockBegin* block = code->at(i);
5723
5724 if (block->number_of_preds() > 1 && !block->is_set(BlockBegin::exception_entry_flag)) {
5725 optimizer.optimize_moves_at_block_end(block);
5726 }
5727 if (block->number_of_sux() == 2) {
5728 optimizer.optimize_moves_at_block_begin(block);
5729 }
5730 }
5731 }
5732
5733
5734 // clear all internal data structures
5735 void EdgeMoveOptimizer::init_instructions() {
5736 _edge_instructions.clear();
5737 _edge_instructions_idx.clear();
5738 }
5739
5740 // append a lir-instruction-list and the index of the current operation in to the list
5741 void EdgeMoveOptimizer::append_instructions(LIR_OpList* instructions, int instructions_idx) {
5742 _edge_instructions.append(instructions);
5743 _edge_instructions_idx.append(instructions_idx);
5744 }
5745
5746 // return the current operation of the given edge (predecessor or successor)
5747 LIR_Op* EdgeMoveOptimizer::instruction_at(int edge) {
5748 LIR_OpList* instructions = _edge_instructions.at(edge);
5749 int idx = _edge_instructions_idx.at(edge);
5750
5751 if (idx < instructions->length()) {
5752 return instructions->at(idx);
5753 } else {
5754 return NULL;
5755 }
5756 }
5757
5758 // removes the current operation of the given edge (predecessor or successor)
5759 void EdgeMoveOptimizer::remove_cur_instruction(int edge, bool decrement_index) {
5760 LIR_OpList* instructions = _edge_instructions.at(edge);
5761 int idx = _edge_instructions_idx.at(edge);
5762 instructions->remove_at(idx);
5763
5764 if (decrement_index) {
5765 _edge_instructions_idx.at_put(edge, idx - 1);
5766 }
5767 }
5768
5769
5770 bool EdgeMoveOptimizer::operations_different(LIR_Op* op1, LIR_Op* op2) {
5771 if (op1 == NULL || op2 == NULL) {
5772 // at least one block is already empty -> no optimization possible
5773 return true;
5774 }
5775
5776 if (op1->code() == lir_move && op2->code() == lir_move) {
5777 assert(op1->as_Op1() != NULL, "move must be LIR_Op1");
5778 assert(op2->as_Op1() != NULL, "move must be LIR_Op1");
5779 LIR_Op1* move1 = (LIR_Op1*)op1;
5780 LIR_Op1* move2 = (LIR_Op1*)op2;
5781 if (move1->info() == move2->info() && move1->in_opr() == move2->in_opr() && move1->result_opr() == move2->result_opr()) {
5782 // these moves are exactly equal and can be optimized
5783 return false;
5784 }
5785
5786 } else if (op1->code() == lir_fxch && op2->code() == lir_fxch) {
5787 assert(op1->as_Op1() != NULL, "fxch must be LIR_Op1");
5788 assert(op2->as_Op1() != NULL, "fxch must be LIR_Op1");
5789 LIR_Op1* fxch1 = (LIR_Op1*)op1;
5790 LIR_Op1* fxch2 = (LIR_Op1*)op2;
5791 if (fxch1->in_opr()->as_jint() == fxch2->in_opr()->as_jint()) {
5792 // equal FPU stack operations can be optimized
5793 return false;
5794 }
5795
5796 } else if (op1->code() == lir_fpop_raw && op2->code() == lir_fpop_raw) {
5797 // equal FPU stack operations can be optimized
5798 return false;
5799 }
5800
5801 // no optimization possible
5802 return true;
5803 }
5804
5805 void EdgeMoveOptimizer::optimize_moves_at_block_end(BlockBegin* block) {
5806 TRACE_LINEAR_SCAN(4, tty->print_cr("optimizing moves at end of block B%d", block->block_id()));
5807
5808 if (block->is_predecessor(block)) {
5809 // currently we can't handle this correctly.
5810 return;
5811 }
5812
5813 init_instructions();
5814 int num_preds = block->number_of_preds();
5815 assert(num_preds > 1, "do not call otherwise");
5816 assert(!block->is_set(BlockBegin::exception_entry_flag), "exception handlers not allowed");
5817
5818 // setup a list with the lir-instructions of all predecessors
5819 int i;
5820 for (i = 0; i < num_preds; i++) {
5821 BlockBegin* pred = block->pred_at(i);
5822 LIR_OpList* pred_instructions = pred->lir()->instructions_list();
5823
5824 if (pred->number_of_sux() != 1) {
5825 // this can happen with switch-statements where multiple edges are between
5826 // the same blocks.
5827 return;
5828 }
5829
5830 assert(pred->number_of_sux() == 1, "can handle only one successor");
5831 assert(pred->sux_at(0) == block, "invalid control flow");
5832 assert(pred_instructions->last()->code() == lir_branch, "block with successor must end with branch");
5833 assert(pred_instructions->last()->as_OpBranch() != NULL, "branch must be LIR_OpBranch");
5834 assert(pred_instructions->last()->as_OpBranch()->cond() == lir_cond_always, "block must end with unconditional branch");
5835
5836 if (pred_instructions->last()->info() != NULL) {
5837 // can not optimize instructions when debug info is needed
5838 return;
5839 }
5840
5841 // ignore the unconditional branch at the end of the block
5842 append_instructions(pred_instructions, pred_instructions->length() - 2);
5843 }
5844
5845
5846 // process lir-instructions while all predecessors end with the same instruction
5847 while (true) {
5848 LIR_Op* op = instruction_at(0);
5849 for (i = 1; i < num_preds; i++) {
5850 if (operations_different(op, instruction_at(i))) {
5851 // these instructions are different and cannot be optimized ->
5852 // no further optimization possible
5853 return;
5854 }
5855 }
5856
5857 TRACE_LINEAR_SCAN(4, tty->print("found instruction that is equal in all %d predecessors: ", num_preds); op->print());
5858
5859 // insert the instruction at the beginning of the current block
5860 block->lir()->insert_before(1, op);
5861
5862 // delete the instruction at the end of all predecessors
5863 for (i = 0; i < num_preds; i++) {
5864 remove_cur_instruction(i, true);
5865 }
5866 }
5867 }
5868
5869
5870 void EdgeMoveOptimizer::optimize_moves_at_block_begin(BlockBegin* block) {
5871 TRACE_LINEAR_SCAN(4, tty->print_cr("optimization moves at begin of block B%d", block->block_id()));
5872
5873 init_instructions();
5874 int num_sux = block->number_of_sux();
5875
5876 LIR_OpList* cur_instructions = block->lir()->instructions_list();
5877
5878 assert(num_sux == 2, "method should not be called otherwise");
5879 assert(cur_instructions->last()->code() == lir_branch, "block with successor must end with branch");
5880 assert(cur_instructions->last()->as_OpBranch() != NULL, "branch must be LIR_OpBranch");
5881 assert(cur_instructions->last()->as_OpBranch()->cond() == lir_cond_always, "block must end with unconditional branch");
5882
5883 if (cur_instructions->last()->info() != NULL) {
5884 // can no optimize instructions when debug info is needed
5885 return;
5886 }
5887
5888 LIR_Op* branch = cur_instructions->at(cur_instructions->length() - 2);
5889 if (branch->info() != NULL || (branch->code() != lir_branch && branch->code() != lir_cond_float_branch)) {
5890 // not a valid case for optimization
5891 // currently, only blocks that end with two branches (conditional branch followed
5892 // by unconditional branch) are optimized
5893 return;
5894 }
5895
5896 // now it is guaranteed that the block ends with two branch instructions.
5897 // the instructions are inserted at the end of the block before these two branches
5898 int insert_idx = cur_instructions->length() - 2;
5899
5900 int i;
5901 #ifdef ASSERT
5902 for (i = insert_idx - 1; i >= 0; i--) {
5903 LIR_Op* op = cur_instructions->at(i);
5904 if ((op->code() == lir_branch || op->code() == lir_cond_float_branch) && ((LIR_OpBranch*)op)->block() != NULL) {
5905 assert(false, "block with two successors can have only two branch instructions");
5906 }
5907 }
5908 #endif
5909
5910 // setup a list with the lir-instructions of all successors
5911 for (i = 0; i < num_sux; i++) {
5912 BlockBegin* sux = block->sux_at(i);
5913 LIR_OpList* sux_instructions = sux->lir()->instructions_list();
5914
5915 assert(sux_instructions->at(0)->code() == lir_label, "block must start with label");
5916
5917 if (sux->number_of_preds() != 1) {
5918 // this can happen with switch-statements where multiple edges are between
5919 // the same blocks.
5920 return;
5921 }
5922 assert(sux->pred_at(0) == block, "invalid control flow");
5923 assert(!sux->is_set(BlockBegin::exception_entry_flag), "exception handlers not allowed");
5924
5925 // ignore the label at the beginning of the block
5926 append_instructions(sux_instructions, 1);
5927 }
5928
5929 // process lir-instructions while all successors begin with the same instruction
5930 while (true) {
5931 LIR_Op* op = instruction_at(0);
5932 for (i = 1; i < num_sux; i++) {
5933 if (operations_different(op, instruction_at(i))) {
5934 // these instructions are different and cannot be optimized ->
5935 // no further optimization possible
5936 return;
5937 }
5938 }
5939
5940 TRACE_LINEAR_SCAN(4, tty->print("----- found instruction that is equal in all %d successors: ", num_sux); op->print());
5941
5942 // insert instruction at end of current block
5943 block->lir()->insert_before(insert_idx, op);
5944 insert_idx++;
5945
5946 // delete the instructions at the beginning of all successors
5947 for (i = 0; i < num_sux; i++) {
5948 remove_cur_instruction(i, false);
5949 }
5950 }
5951 }
5952
5953
5954 // Implementation of ControlFlowOptimizer
5955
5956 ControlFlowOptimizer::ControlFlowOptimizer() :
5957 _original_preds(4)
5958 {
5959 }
5960
5961 void ControlFlowOptimizer::optimize(BlockList* code) {
5962 ControlFlowOptimizer optimizer = ControlFlowOptimizer();
5963
5964 // push the OSR entry block to the end so that we're not jumping over it.
5965 BlockBegin* osr_entry = code->at(0)->end()->as_Base()->osr_entry();
5966 if (osr_entry) {
5967 int index = osr_entry->linear_scan_number();
5968 assert(code->at(index) == osr_entry, "wrong index");
5969 code->remove_at(index);
5970 code->append(osr_entry);
5971 }
5972
5973 optimizer.reorder_short_loops(code);
5974 optimizer.delete_empty_blocks(code);
5975 optimizer.delete_unnecessary_jumps(code);
5976 optimizer.delete_jumps_to_return(code);
5977 }
5978
5979 void ControlFlowOptimizer::reorder_short_loop(BlockList* code, BlockBegin* header_block, int header_idx) {
5980 int i = header_idx + 1;
5981 int max_end = MIN2(header_idx + ShortLoopSize, code->length());
5982 while (i < max_end && code->at(i)->loop_depth() >= header_block->loop_depth()) {
5983 i++;
5984 }
5985
5986 if (i == code->length() || code->at(i)->loop_depth() < header_block->loop_depth()) {
5987 int end_idx = i - 1;
5988 BlockBegin* end_block = code->at(end_idx);
5989
5990 if (end_block->number_of_sux() == 1 && end_block->sux_at(0) == header_block) {
5991 // short loop from header_idx to end_idx found -> reorder blocks such that
5992 // the header_block is the last block instead of the first block of the loop
5993 TRACE_LINEAR_SCAN(1, tty->print_cr("Reordering short loop: length %d, header B%d, end B%d",
5994 end_idx - header_idx + 1,
5995 header_block->block_id(), end_block->block_id()));
5996
5997 for (int j = header_idx; j < end_idx; j++) {
5998 code->at_put(j, code->at(j + 1));
5999 }
6000 code->at_put(end_idx, header_block);
6001
6002 // correct the flags so that any loop alignment occurs in the right place.
6003 assert(code->at(end_idx)->is_set(BlockBegin::backward_branch_target_flag), "must be backward branch target");
6004 code->at(end_idx)->clear(BlockBegin::backward_branch_target_flag);
6005 code->at(header_idx)->set(BlockBegin::backward_branch_target_flag);
6006 }
6007 }
6008 }
6009
6010 void ControlFlowOptimizer::reorder_short_loops(BlockList* code) {
6011 for (int i = code->length() - 1; i >= 0; i--) {
6012 BlockBegin* block = code->at(i);
6013
6014 if (block->is_set(BlockBegin::linear_scan_loop_header_flag)) {
6015 reorder_short_loop(code, block, i);
6016 }
6017 }
6018
6019 DEBUG_ONLY(verify(code));
6020 }
6021
6022 // only blocks with exactly one successor can be deleted. Such blocks
6023 // must always end with an unconditional branch to this successor
6024 bool ControlFlowOptimizer::can_delete_block(BlockBegin* block) {
6025 if (block->number_of_sux() != 1 || block->number_of_exception_handlers() != 0 || block->is_entry_block()) {
6026 return false;
6027 }
6028
6029 LIR_OpList* instructions = block->lir()->instructions_list();
6030
6031 assert(instructions->length() >= 2, "block must have label and branch");
6032 assert(instructions->at(0)->code() == lir_label, "first instruction must always be a label");
6033 assert(instructions->last()->as_OpBranch() != NULL, "last instrcution must always be a branch");
6034 assert(instructions->last()->as_OpBranch()->cond() == lir_cond_always, "branch must be unconditional");
6035 assert(instructions->last()->as_OpBranch()->block() == block->sux_at(0), "branch target must be the successor");
6036
6037 // block must have exactly one successor
6038
6039 if (instructions->length() == 2 && instructions->last()->info() == NULL) {
6040 return true;
6041 }
6042 return false;
6043 }
6044
6045 // substitute branch targets in all branch-instructions of this blocks
6046 void ControlFlowOptimizer::substitute_branch_target(BlockBegin* block, BlockBegin* target_from, BlockBegin* target_to) {
6047 TRACE_LINEAR_SCAN(3, tty->print_cr("Deleting empty block: substituting from B%d to B%d inside B%d", target_from->block_id(), target_to->block_id(), block->block_id()));
6048
6049 LIR_OpList* instructions = block->lir()->instructions_list();
6050
6051 assert(instructions->at(0)->code() == lir_label, "first instruction must always be a label");
6052 for (int i = instructions->length() - 1; i >= 1; i--) {
6053 LIR_Op* op = instructions->at(i);
6054
6055 if (op->code() == lir_branch || op->code() == lir_cond_float_branch) {
6056 assert(op->as_OpBranch() != NULL, "branch must be of type LIR_OpBranch");
6057 LIR_OpBranch* branch = (LIR_OpBranch*)op;
6058
6059 if (branch->block() == target_from) {
6060 branch->change_block(target_to);
6061 }
6062 if (branch->ublock() == target_from) {
6063 branch->change_ublock(target_to);
6064 }
6065 }
6066 }
6067 }
6068
6069 void ControlFlowOptimizer::delete_empty_blocks(BlockList* code) {
6070 int old_pos = 0;
6071 int new_pos = 0;
6072 int num_blocks = code->length();
6073
6074 while (old_pos < num_blocks) {
6075 BlockBegin* block = code->at(old_pos);
6076
6077 if (can_delete_block(block)) {
6078 BlockBegin* new_target = block->sux_at(0);
6079
6080 // propagate backward branch target flag for correct code alignment
6081 if (block->is_set(BlockBegin::backward_branch_target_flag)) {
6082 new_target->set(BlockBegin::backward_branch_target_flag);
6083 }
6084
6085 // collect a list with all predecessors that contains each predecessor only once
6086 // the predecessors of cur are changed during the substitution, so a copy of the
6087 // predecessor list is necessary
6088 int j;
6089 _original_preds.clear();
6090 for (j = block->number_of_preds() - 1; j >= 0; j--) {
6091 BlockBegin* pred = block->pred_at(j);
6092 if (_original_preds.index_of(pred) == -1) {
6093 _original_preds.append(pred);
6094 }
6095 }
6096
6097 for (j = _original_preds.length() - 1; j >= 0; j--) {
6098 BlockBegin* pred = _original_preds.at(j);
6099 substitute_branch_target(pred, block, new_target);
6100 pred->substitute_sux(block, new_target);
6101 }
6102 } else {
6103 // adjust position of this block in the block list if blocks before
6104 // have been deleted
6105 if (new_pos != old_pos) {
6106 code->at_put(new_pos, code->at(old_pos));
6107 }
6108 new_pos++;
6109 }
6110 old_pos++;
6111 }
6112 code->truncate(new_pos);
6113
6114 DEBUG_ONLY(verify(code));
6115 }
6116
6117 void ControlFlowOptimizer::delete_unnecessary_jumps(BlockList* code) {
6118 // skip the last block because there a branch is always necessary
6119 for (int i = code->length() - 2; i >= 0; i--) {
6120 BlockBegin* block = code->at(i);
6121 LIR_OpList* instructions = block->lir()->instructions_list();
6122
6123 LIR_Op* last_op = instructions->last();
6124 if (last_op->code() == lir_branch) {
6125 assert(last_op->as_OpBranch() != NULL, "branch must be of type LIR_OpBranch");
6126 LIR_OpBranch* last_branch = (LIR_OpBranch*)last_op;
6127
6128 assert(last_branch->block() != NULL, "last branch must always have a block as target");
6129 assert(last_branch->label() == last_branch->block()->label(), "must be equal");
6130
6131 if (last_branch->info() == NULL) {
6132 if (last_branch->block() == code->at(i + 1)) {
6133
6134 TRACE_LINEAR_SCAN(3, tty->print_cr("Deleting unconditional branch at end of block B%d", block->block_id()));
6135
6136 // delete last branch instruction
6137 instructions->truncate(instructions->length() - 1);
6138
6139 } else {
6140 LIR_Op* prev_op = instructions->at(instructions->length() - 2);
6141 if (prev_op->code() == lir_branch || prev_op->code() == lir_cond_float_branch) {
6142 assert(prev_op->as_OpBranch() != NULL, "branch must be of type LIR_OpBranch");
6143 LIR_OpBranch* prev_branch = (LIR_OpBranch*)prev_op;
6144
6145 if (prev_branch->block() == code->at(i + 1) && prev_branch->info() == NULL) {
6146
6147 TRACE_LINEAR_SCAN(3, tty->print_cr("Negating conditional branch and deleting unconditional branch at end of block B%d", block->block_id()));
6148
6149 // eliminate a conditional branch to the immediate successor
6150 prev_branch->change_block(last_branch->block());
6151 prev_branch->negate_cond();
6152 instructions->truncate(instructions->length() - 1);
6153 }
6154 }
6155 }
6156 }
6157 }
6158 }
6159
6160 DEBUG_ONLY(verify(code));
6161 }
6162
6163 void ControlFlowOptimizer::delete_jumps_to_return(BlockList* code) {
6164 #ifdef ASSERT
6165 BitMap return_converted(BlockBegin::number_of_blocks());
6166 return_converted.clear();
6167 #endif
6168
6169 for (int i = code->length() - 1; i >= 0; i--) {
6170 BlockBegin* block = code->at(i);
6171 LIR_OpList* cur_instructions = block->lir()->instructions_list();
6172 LIR_Op* cur_last_op = cur_instructions->last();
6173
6174 assert(cur_instructions->at(0)->code() == lir_label, "first instruction must always be a label");
6175 if (cur_instructions->length() == 2 && cur_last_op->code() == lir_return) {
6176 // the block contains only a label and a return
6177 // if a predecessor ends with an unconditional jump to this block, then the jump
6178 // can be replaced with a return instruction
6179 //
6180 // Note: the original block with only a return statement cannot be deleted completely
6181 // because the predecessors might have other (conditional) jumps to this block
6182 // -> this may lead to unnecesary return instructions in the final code
6183
6184 assert(cur_last_op->info() == NULL, "return instructions do not have debug information");
6185 assert(block->number_of_sux() == 0 ||
6186 (return_converted.at(block->block_id()) && block->number_of_sux() == 1),
6187 "blocks that end with return must not have successors");
6188
6189 assert(cur_last_op->as_Op1() != NULL, "return must be LIR_Op1");
6190 LIR_Opr return_opr = ((LIR_Op1*)cur_last_op)->in_opr();
6191
6192 for (int j = block->number_of_preds() - 1; j >= 0; j--) {
6193 BlockBegin* pred = block->pred_at(j);
6194 LIR_OpList* pred_instructions = pred->lir()->instructions_list();
6195 LIR_Op* pred_last_op = pred_instructions->last();
6196
6197 if (pred_last_op->code() == lir_branch) {
6198 assert(pred_last_op->as_OpBranch() != NULL, "branch must be LIR_OpBranch");
6199 LIR_OpBranch* pred_last_branch = (LIR_OpBranch*)pred_last_op;
6200
6201 if (pred_last_branch->block() == block && pred_last_branch->cond() == lir_cond_always && pred_last_branch->info() == NULL) {
6202 // replace the jump to a return with a direct return
6203 // Note: currently the edge between the blocks is not deleted
6204 pred_instructions->at_put(pred_instructions->length() - 1, new LIR_Op1(lir_return, return_opr));
6205 #ifdef ASSERT
6206 return_converted.set_bit(pred->block_id());
6207 #endif
6208 }
6209 }
6210 }
6211 }
6212 }
6213 }
6214
6215
6216 #ifdef ASSERT
6217 void ControlFlowOptimizer::verify(BlockList* code) {
6218 for (int i = 0; i < code->length(); i++) {
6219 BlockBegin* block = code->at(i);
6220 LIR_OpList* instructions = block->lir()->instructions_list();
6221
6222 int j;
6223 for (j = 0; j < instructions->length(); j++) {
6224 LIR_OpBranch* op_branch = instructions->at(j)->as_OpBranch();
6225
6226 if (op_branch != NULL) {
6227 assert(op_branch->block() == NULL || code->index_of(op_branch->block()) != -1, "branch target not valid");
6228 assert(op_branch->ublock() == NULL || code->index_of(op_branch->ublock()) != -1, "branch target not valid");
6229 }
6230 }
6231
6232 for (j = 0; j < block->number_of_sux() - 1; j++) {
6233 BlockBegin* sux = block->sux_at(j);
6234 assert(code->index_of(sux) != -1, "successor not valid");
6235 }
6236
6237 for (j = 0; j < block->number_of_preds() - 1; j++) {
6238 BlockBegin* pred = block->pred_at(j);
6239 assert(code->index_of(pred) != -1, "successor not valid");
6240 }
6241 }
6242 }
6243 #endif
6244
6245
6246 #ifndef PRODUCT
6247
6248 // Implementation of LinearStatistic
6249
6250 const char* LinearScanStatistic::counter_name(int counter_idx) {
6251 switch (counter_idx) {
6252 case counter_method: return "compiled methods";
6253 case counter_fpu_method: return "methods using fpu";
6254 case counter_loop_method: return "methods with loops";
6255 case counter_exception_method:return "methods with xhandler";
6256
6257 case counter_loop: return "loops";
6258 case counter_block: return "blocks";
6259 case counter_loop_block: return "blocks inside loop";
6260 case counter_exception_block: return "exception handler entries";
6261 case counter_interval: return "intervals";
6262 case counter_fixed_interval: return "fixed intervals";
6263 case counter_range: return "ranges";
6264 case counter_fixed_range: return "fixed ranges";
6265 case counter_use_pos: return "use positions";
6266 case counter_fixed_use_pos: return "fixed use positions";
6267 case counter_spill_slots: return "spill slots";
6268
6269 // counter for classes of lir instructions
6270 case counter_instruction: return "total instructions";
6271 case counter_label: return "labels";
6272 case counter_entry: return "method entries";
6273 case counter_return: return "method returns";
6274 case counter_call: return "method calls";
6275 case counter_move: return "moves";
6276 case counter_cmp: return "compare";
6277 case counter_cond_branch: return "conditional branches";
6278 case counter_uncond_branch: return "unconditional branches";
6279 case counter_stub_branch: return "branches to stub";
6280 case counter_alu: return "artithmetic + logic";
6281 case counter_alloc: return "allocations";
6282 case counter_sync: return "synchronisation";
6283 case counter_throw: return "throw";
6284 case counter_unwind: return "unwind";
6285 case counter_typecheck: return "type+null-checks";
6286 case counter_fpu_stack: return "fpu-stack";
6287 case counter_misc_inst: return "other instructions";
6288 case counter_other_inst: return "misc. instructions";
6289
6290 // counter for different types of moves
6291 case counter_move_total: return "total moves";
6292 case counter_move_reg_reg: return "register->register";
6293 case counter_move_reg_stack: return "register->stack";
6294 case counter_move_stack_reg: return "stack->register";
6295 case counter_move_stack_stack:return "stack->stack";
6296 case counter_move_reg_mem: return "register->memory";
6297 case counter_move_mem_reg: return "memory->register";
6298 case counter_move_const_any: return "constant->any";
6299
6300 case blank_line_1: return "";
6301 case blank_line_2: return "";
6302
6303 default: ShouldNotReachHere(); return "";
6304 }
6305 }
6306
6307 LinearScanStatistic::Counter LinearScanStatistic::base_counter(int counter_idx) {
6308 if (counter_idx == counter_fpu_method || counter_idx == counter_loop_method || counter_idx == counter_exception_method) {
6309 return counter_method;
6310 } else if (counter_idx == counter_loop_block || counter_idx == counter_exception_block) {
6311 return counter_block;
6312 } else if (counter_idx >= counter_instruction && counter_idx <= counter_other_inst) {
6313 return counter_instruction;
6314 } else if (counter_idx >= counter_move_total && counter_idx <= counter_move_const_any) {
6315 return counter_move_total;
6316 }
6317 return invalid_counter;
6318 }
6319
6320 LinearScanStatistic::LinearScanStatistic() {
6321 for (int i = 0; i < number_of_counters; i++) {
6322 _counters_sum[i] = 0;
6323 _counters_max[i] = -1;
6324 }
6325
6326 }
6327
6328 // add the method-local numbers to the total sum
6329 void LinearScanStatistic::sum_up(LinearScanStatistic &method_statistic) {
6330 for (int i = 0; i < number_of_counters; i++) {
6331 _counters_sum[i] += method_statistic._counters_sum[i];
6332 _counters_max[i] = MAX2(_counters_max[i], method_statistic._counters_sum[i]);
6333 }
6334 }
6335
6336 void LinearScanStatistic::print(const char* title) {
6337 if (CountLinearScan || TraceLinearScanLevel > 0) {
6338 tty->cr();
6339 tty->print_cr("***** LinearScan statistic - %s *****", title);
6340
6341 for (int i = 0; i < number_of_counters; i++) {
6342 if (_counters_sum[i] > 0 || _counters_max[i] >= 0) {
6343 tty->print("%25s: %8d", counter_name(i), _counters_sum[i]);
6344
6345 if (base_counter(i) != invalid_counter) {
6346 tty->print(" (%5.1f%%) ", _counters_sum[i] * 100.0 / _counters_sum[base_counter(i)]);
6347 } else {
6348 tty->print(" ");
6349 }
6350
6351 if (_counters_max[i] >= 0) {
6352 tty->print("%8d", _counters_max[i]);
6353 }
6354 }
6355 tty->cr();
6356 }
6357 }
6358 }
6359
6360 void LinearScanStatistic::collect(LinearScan* allocator) {
6361 inc_counter(counter_method);
6362 if (allocator->has_fpu_registers()) {
6363 inc_counter(counter_fpu_method);
6364 }
6365 if (allocator->num_loops() > 0) {
6366 inc_counter(counter_loop_method);
6367 }
6368 inc_counter(counter_loop, allocator->num_loops());
6369 inc_counter(counter_spill_slots, allocator->max_spills());
6370
6371 int i;
6372 for (i = 0; i < allocator->interval_count(); i++) {
6373 Interval* cur = allocator->interval_at(i);
6374
6375 if (cur != NULL) {
6376 inc_counter(counter_interval);
6377 inc_counter(counter_use_pos, cur->num_use_positions());
6378 if (LinearScan::is_precolored_interval(cur)) {
6379 inc_counter(counter_fixed_interval);
6380 inc_counter(counter_fixed_use_pos, cur->num_use_positions());
6381 }
6382
6383 Range* range = cur->first();
6384 while (range != Range::end()) {
6385 inc_counter(counter_range);
6386 if (LinearScan::is_precolored_interval(cur)) {
6387 inc_counter(counter_fixed_range);
6388 }
6389 range = range->next();
6390 }
6391 }
6392 }
6393
6394 bool has_xhandlers = false;
6395 // Note: only count blocks that are in code-emit order
6396 for (i = 0; i < allocator->ir()->code()->length(); i++) {
6397 BlockBegin* cur = allocator->ir()->code()->at(i);
6398
6399 inc_counter(counter_block);
6400 if (cur->loop_depth() > 0) {
6401 inc_counter(counter_loop_block);
6402 }
6403 if (cur->is_set(BlockBegin::exception_entry_flag)) {
6404 inc_counter(counter_exception_block);
6405 has_xhandlers = true;
6406 }
6407
6408 LIR_OpList* instructions = cur->lir()->instructions_list();
6409 for (int j = 0; j < instructions->length(); j++) {
6410 LIR_Op* op = instructions->at(j);
6411
6412 inc_counter(counter_instruction);
6413
6414 switch (op->code()) {
6415 case lir_label: inc_counter(counter_label); break;
6416 case lir_std_entry:
6417 case lir_osr_entry: inc_counter(counter_entry); break;
6418 case lir_return: inc_counter(counter_return); break;
6419
6420 case lir_rtcall:
6421 case lir_static_call:
6422 case lir_optvirtual_call:
6423 case lir_virtual_call: inc_counter(counter_call); break;
6424
6425 case lir_move: {
6426 inc_counter(counter_move);
6427 inc_counter(counter_move_total);
6428
6429 LIR_Opr in = op->as_Op1()->in_opr();
6430 LIR_Opr res = op->as_Op1()->result_opr();
6431 if (in->is_register()) {
6432 if (res->is_register()) {
6433 inc_counter(counter_move_reg_reg);
6434 } else if (res->is_stack()) {
6435 inc_counter(counter_move_reg_stack);
6436 } else if (res->is_address()) {
6437 inc_counter(counter_move_reg_mem);
6438 } else {
6439 ShouldNotReachHere();
6440 }
6441 } else if (in->is_stack()) {
6442 if (res->is_register()) {
6443 inc_counter(counter_move_stack_reg);
6444 } else {
6445 inc_counter(counter_move_stack_stack);
6446 }
6447 } else if (in->is_address()) {
6448 assert(res->is_register(), "must be");
6449 inc_counter(counter_move_mem_reg);
6450 } else if (in->is_constant()) {
6451 inc_counter(counter_move_const_any);
6452 } else {
6453 ShouldNotReachHere();
6454 }
6455 break;
6456 }
6457
6458 case lir_cmp: inc_counter(counter_cmp); break;
6459
6460 case lir_branch:
6461 case lir_cond_float_branch: {
6462 LIR_OpBranch* branch = op->as_OpBranch();
6463 if (branch->block() == NULL) {
6464 inc_counter(counter_stub_branch);
6465 } else if (branch->cond() == lir_cond_always) {
6466 inc_counter(counter_uncond_branch);
6467 } else {
6468 inc_counter(counter_cond_branch);
6469 }
6470 break;
6471 }
6472
6473 case lir_neg:
6474 case lir_add:
6475 case lir_sub:
6476 case lir_mul:
6477 case lir_mul_strictfp:
6478 case lir_div:
6479 case lir_div_strictfp:
6480 case lir_rem:
6481 case lir_sqrt:
6482 case lir_sin:
6483 case lir_cos:
6484 case lir_abs:
6485 case lir_log10:
6486 case lir_log:
6487 case lir_logic_and:
6488 case lir_logic_or:
6489 case lir_logic_xor:
6490 case lir_shl:
6491 case lir_shr:
6492 case lir_ushr: inc_counter(counter_alu); break;
6493
6494 case lir_alloc_object:
6495 case lir_alloc_array: inc_counter(counter_alloc); break;
6496
6497 case lir_monaddr:
6498 case lir_lock:
6499 case lir_unlock: inc_counter(counter_sync); break;
6500
6501 case lir_throw: inc_counter(counter_throw); break;
6502
6503 case lir_unwind: inc_counter(counter_unwind); break;
6504
6505 case lir_null_check:
6506 case lir_leal:
6507 case lir_instanceof:
6508 case lir_checkcast:
6509 case lir_store_check: inc_counter(counter_typecheck); break;
6510
6511 case lir_fpop_raw:
6512 case lir_fxch:
6513 case lir_fld: inc_counter(counter_fpu_stack); break;
6514
6515 case lir_nop:
6516 case lir_push:
6517 case lir_pop:
6518 case lir_convert:
6519 case lir_roundfp:
6520 case lir_cmove: inc_counter(counter_misc_inst); break;
6521
6522 default: inc_counter(counter_other_inst); break;
6523 }
6524 }
6525 }
6526
6527 if (has_xhandlers) {
6528 inc_counter(counter_exception_method);
6529 }
6530 }
6531
6532 void LinearScanStatistic::compute(LinearScan* allocator, LinearScanStatistic &global_statistic) {
6533 if (CountLinearScan || TraceLinearScanLevel > 0) {
6534
6535 LinearScanStatistic local_statistic = LinearScanStatistic();
6536
6537 local_statistic.collect(allocator);
6538 global_statistic.sum_up(local_statistic);
6539
6540 if (TraceLinearScanLevel > 2) {
6541 local_statistic.print("current local statistic");
6542 }
6543 }
6544 }
6545
6546
6547 // Implementation of LinearTimers
6548
6549 LinearScanTimers::LinearScanTimers() {
6550 for (int i = 0; i < number_of_timers; i++) {
6551 timer(i)->reset();
6552 }
6553 }
6554
6555 const char* LinearScanTimers::timer_name(int idx) {
6556 switch (idx) {
6557 case timer_do_nothing: return "Nothing (Time Check)";
6558 case timer_number_instructions: return "Number Instructions";
6559 case timer_compute_local_live_sets: return "Local Live Sets";
6560 case timer_compute_global_live_sets: return "Global Live Sets";
6561 case timer_build_intervals: return "Build Intervals";
6562 case timer_sort_intervals_before: return "Sort Intervals Before";
6563 case timer_allocate_registers: return "Allocate Registers";
6564 case timer_resolve_data_flow: return "Resolve Data Flow";
6565 case timer_sort_intervals_after: return "Sort Intervals After";
6566 case timer_eliminate_spill_moves: return "Spill optimization";
6567 case timer_assign_reg_num: return "Assign Reg Num";
6568 case timer_allocate_fpu_stack: return "Allocate FPU Stack";
6569 case timer_optimize_lir: return "Optimize LIR";
6570 default: ShouldNotReachHere(); return "";
6571 }
6572 }
6573
6574 void LinearScanTimers::begin_method() {
6575 if (TimeEachLinearScan) {
6576 // reset all timers to measure only current method
6577 for (int i = 0; i < number_of_timers; i++) {
6578 timer(i)->reset();
6579 }
6580 }
6581 }
6582
6583 void LinearScanTimers::end_method(LinearScan* allocator) {
6584 if (TimeEachLinearScan) {
6585
6586 double c = timer(timer_do_nothing)->seconds();
6587 double total = 0;
6588 for (int i = 1; i < number_of_timers; i++) {
6589 total += timer(i)->seconds() - c;
6590 }
6591
6592 if (total >= 0.0005) {
6593 // print all information in one line for automatic processing
6594 tty->print("@"); allocator->compilation()->method()->print_name();
6595
6596 tty->print("@ %d ", allocator->compilation()->method()->code_size());
6597 tty->print("@ %d ", allocator->block_at(allocator->block_count() - 1)->last_lir_instruction_id() / 2);
6598 tty->print("@ %d ", allocator->block_count());
6599 tty->print("@ %d ", allocator->num_virtual_regs());
6600 tty->print("@ %d ", allocator->interval_count());
6601 tty->print("@ %d ", allocator->_num_calls);
6602 tty->print("@ %d ", allocator->num_loops());
6603
6604 tty->print("@ %6.6f ", total);
6605 for (int i = 1; i < number_of_timers; i++) {
6606 tty->print("@ %4.1f ", ((timer(i)->seconds() - c) / total) * 100);
6607 }
6608 tty->cr();
6609 }
6610 }
6611 }
6612
6613 void LinearScanTimers::print(double total_time) {
6614 if (TimeLinearScan) {
6615 // correction value: sum of dummy-timer that only measures the time that
6616 // is necesary to start and stop itself
6617 double c = timer(timer_do_nothing)->seconds();
6618
6619 for (int i = 0; i < number_of_timers; i++) {
6620 double t = timer(i)->seconds();
6621 tty->print_cr(" %25s: %6.3f s (%4.1f%%) corrected: %6.3f s (%4.1f%%)", timer_name(i), t, (t / total_time) * 100.0, t - c, (t - c) / (total_time - 2 * number_of_timers * c) * 100);
6622 }
6623 }
6624 }
6625
6626 #endif // #ifndef PRODUCT