1 /*
2 * Copyright (c) 2005, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "c1/c1_CFGPrinter.hpp"
27 #include "c1/c1_CodeStubs.hpp"
28 #include "c1/c1_Compilation.hpp"
29 #include "c1/c1_FrameMap.hpp"
30 #include "c1/c1_IR.hpp"
31 #include "c1/c1_LIRGenerator.hpp"
32 #include "c1/c1_LinearScan.hpp"
33 #include "c1/c1_ValueStack.hpp"
34 #include "code/vmreg.inline.hpp"
35 #include "runtime/timerTrace.hpp"
36 #include "utilities/bitMap.inline.hpp"
37
38 #ifndef PRODUCT
39
40 static LinearScanStatistic _stat_before_alloc;
41 static LinearScanStatistic _stat_after_asign;
42 static LinearScanStatistic _stat_final;
43
44 static LinearScanTimers _total_timer;
45
46 // helper macro for short definition of timer
47 #define TIME_LINEAR_SCAN(timer_name) TraceTime _block_timer("", _total_timer.timer(LinearScanTimers::timer_name), TimeLinearScan || TimeEachLinearScan, Verbose);
48
49 // helper macro for short definition of trace-output inside code
50 #define TRACE_LINEAR_SCAN(level, code) \
51 if (TraceLinearScanLevel >= level) { \
52 code; \
53 }
54
55 #else
56
57 #define TIME_LINEAR_SCAN(timer_name)
58 #define TRACE_LINEAR_SCAN(level, code)
59
60 #endif
61
62 // Map BasicType to spill size in 32-bit words, matching VMReg's notion of words
63 #ifdef _LP64
64 static int type2spill_size[T_CONFLICT+1]={ -1, 0, 0, 0, 1, 1, 1, 2, 1, 1, 1, 2, 2, 2, 0, 2, 1, 2, 1, -1};
65 #else
66 static int type2spill_size[T_CONFLICT+1]={ -1, 0, 0, 0, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 0, 1, -1, 1, 1, -1};
67 #endif
68
69
70 // Implementation of LinearScan
71
72 LinearScan::LinearScan(IR* ir, LIRGenerator* gen, FrameMap* frame_map)
73 : _compilation(ir->compilation())
74 , _ir(ir)
75 , _gen(gen)
76 , _frame_map(frame_map)
77 , _cached_blocks(*ir->linear_scan_order())
78 , _num_virtual_regs(gen->max_virtual_register_number())
79 , _has_fpu_registers(false)
80 , _num_calls(-1)
81 , _max_spills(0)
82 , _unused_spill_slot(-1)
83 , _intervals(0) // initialized later with correct length
84 , _new_intervals_from_allocation(NULL)
85 , _sorted_intervals(NULL)
86 , _needs_full_resort(false)
87 , _lir_ops(0) // initialized later with correct length
88 , _block_of_op(0) // initialized later with correct length
89 , _has_info(0)
90 , _has_call(0)
91 , _interval_in_loop(0) // initialized later with correct length
92 , _scope_value_cache(0) // initialized later with correct length
93 #ifdef IA32
94 , _fpu_stack_allocator(NULL)
95 #endif
96 {
97 assert(this->ir() != NULL, "check if valid");
98 assert(this->compilation() != NULL, "check if valid");
99 assert(this->gen() != NULL, "check if valid");
100 assert(this->frame_map() != NULL, "check if valid");
101 }
102
103
104 // ********** functions for converting LIR-Operands to register numbers
105 //
106 // Emulate a flat register file comprising physical integer registers,
107 // physical floating-point registers and virtual registers, in that order.
108 // Virtual registers already have appropriate numbers, since V0 is
109 // the number of physical registers.
110 // Returns -1 for hi word if opr is a single word operand.
111 //
112 // Note: the inverse operation (calculating an operand for register numbers)
113 // is done in calc_operand_for_interval()
114
115 int LinearScan::reg_num(LIR_Opr opr) {
116 assert(opr->is_register(), "should not call this otherwise");
117
118 if (opr->is_virtual_register()) {
119 assert(opr->vreg_number() >= nof_regs, "found a virtual register with a fixed-register number");
120 return opr->vreg_number();
121 } else if (opr->is_single_cpu()) {
122 return opr->cpu_regnr();
123 } else if (opr->is_double_cpu()) {
124 return opr->cpu_regnrLo();
125 #ifdef X86
126 } else if (opr->is_single_xmm()) {
127 return opr->fpu_regnr() + pd_first_xmm_reg;
128 } else if (opr->is_double_xmm()) {
129 return opr->fpu_regnrLo() + pd_first_xmm_reg;
130 #endif
131 } else if (opr->is_single_fpu()) {
132 return opr->fpu_regnr() + pd_first_fpu_reg;
133 } else if (opr->is_double_fpu()) {
134 return opr->fpu_regnrLo() + pd_first_fpu_reg;
135 } else {
136 ShouldNotReachHere();
137 return -1;
138 }
139 }
140
141 int LinearScan::reg_numHi(LIR_Opr opr) {
142 assert(opr->is_register(), "should not call this otherwise");
143
144 if (opr->is_virtual_register()) {
145 return -1;
146 } else if (opr->is_single_cpu()) {
147 return -1;
148 } else if (opr->is_double_cpu()) {
149 return opr->cpu_regnrHi();
150 #ifdef X86
151 } else if (opr->is_single_xmm()) {
152 return -1;
153 } else if (opr->is_double_xmm()) {
154 return -1;
155 #endif
156 } else if (opr->is_single_fpu()) {
157 return -1;
158 } else if (opr->is_double_fpu()) {
159 return opr->fpu_regnrHi() + pd_first_fpu_reg;
160 } else {
161 ShouldNotReachHere();
162 return -1;
163 }
164 }
165
166
167 // ********** functions for classification of intervals
168
169 bool LinearScan::is_precolored_interval(const Interval* i) {
170 return i->reg_num() < LinearScan::nof_regs;
171 }
172
173 bool LinearScan::is_virtual_interval(const Interval* i) {
174 return i->reg_num() >= LIR_OprDesc::vreg_base;
175 }
176
177 bool LinearScan::is_precolored_cpu_interval(const Interval* i) {
178 return i->reg_num() < LinearScan::nof_cpu_regs;
179 }
180
181 bool LinearScan::is_virtual_cpu_interval(const Interval* i) {
182 #if defined(__SOFTFP__) || defined(E500V2)
183 return i->reg_num() >= LIR_OprDesc::vreg_base;
184 #else
185 return i->reg_num() >= LIR_OprDesc::vreg_base && (i->type() != T_FLOAT && i->type() != T_DOUBLE);
186 #endif // __SOFTFP__ or E500V2
187 }
188
189 bool LinearScan::is_precolored_fpu_interval(const Interval* i) {
190 return i->reg_num() >= LinearScan::nof_cpu_regs && i->reg_num() < LinearScan::nof_regs;
191 }
192
193 bool LinearScan::is_virtual_fpu_interval(const Interval* i) {
194 #if defined(__SOFTFP__) || defined(E500V2)
195 return false;
196 #else
197 return i->reg_num() >= LIR_OprDesc::vreg_base && (i->type() == T_FLOAT || i->type() == T_DOUBLE);
198 #endif // __SOFTFP__ or E500V2
199 }
200
201 bool LinearScan::is_in_fpu_register(const Interval* i) {
202 // fixed intervals not needed for FPU stack allocation
203 return i->reg_num() >= nof_regs && pd_first_fpu_reg <= i->assigned_reg() && i->assigned_reg() <= pd_last_fpu_reg;
204 }
205
206 bool LinearScan::is_oop_interval(const Interval* i) {
207 // fixed intervals never contain oops
208 return i->reg_num() >= nof_regs && i->type() == T_OBJECT;
209 }
210
211
212 // ********** General helper functions
213
214 // compute next unused stack index that can be used for spilling
215 int LinearScan::allocate_spill_slot(bool double_word) {
216 int spill_slot;
217 if (double_word) {
218 if ((_max_spills & 1) == 1) {
219 // alignment of double-word values
220 // the hole because of the alignment is filled with the next single-word value
221 assert(_unused_spill_slot == -1, "wasting a spill slot");
222 _unused_spill_slot = _max_spills;
223 _max_spills++;
224 }
225 spill_slot = _max_spills;
226 _max_spills += 2;
227
228 } else if (_unused_spill_slot != -1) {
229 // re-use hole that was the result of a previous double-word alignment
230 spill_slot = _unused_spill_slot;
231 _unused_spill_slot = -1;
232
233 } else {
234 spill_slot = _max_spills;
235 _max_spills++;
236 }
237
238 int result = spill_slot + LinearScan::nof_regs + frame_map()->argcount();
239
240 // the class OopMapValue uses only 11 bits for storing the name of the
241 // oop location. So a stack slot bigger than 2^11 leads to an overflow
242 // that is not reported in product builds. Prevent this by checking the
243 // spill slot here (altough this value and the later used location name
244 // are slightly different)
245 if (result > 2000) {
246 bailout("too many stack slots used");
247 }
248
249 return result;
250 }
251
252 void LinearScan::assign_spill_slot(Interval* it) {
253 // assign the canonical spill slot of the parent (if a part of the interval
254 // is already spilled) or allocate a new spill slot
255 if (it->canonical_spill_slot() >= 0) {
256 it->assign_reg(it->canonical_spill_slot());
257 } else {
258 int spill = allocate_spill_slot(type2spill_size[it->type()] == 2);
259 it->set_canonical_spill_slot(spill);
260 it->assign_reg(spill);
261 }
262 }
263
264 void LinearScan::propagate_spill_slots() {
265 if (!frame_map()->finalize_frame(max_spills())) {
266 bailout("frame too large");
267 }
268 }
269
270 // create a new interval with a predefined reg_num
271 // (only used for parent intervals that are created during the building phase)
272 Interval* LinearScan::create_interval(int reg_num) {
273 assert(_intervals.at(reg_num) == NULL, "overwriting exisiting interval");
274
275 Interval* interval = new Interval(reg_num);
276 _intervals.at_put(reg_num, interval);
277
278 // assign register number for precolored intervals
279 if (reg_num < LIR_OprDesc::vreg_base) {
280 interval->assign_reg(reg_num);
281 }
282 return interval;
283 }
284
285 // assign a new reg_num to the interval and append it to the list of intervals
286 // (only used for child intervals that are created during register allocation)
287 void LinearScan::append_interval(Interval* it) {
288 it->set_reg_num(_intervals.length());
289 _intervals.append(it);
290 IntervalList* new_intervals = _new_intervals_from_allocation;
291 if (new_intervals == NULL) {
292 new_intervals = _new_intervals_from_allocation = new IntervalList();
293 }
294 new_intervals->append(it);
295 }
296
297 // copy the vreg-flags if an interval is split
298 void LinearScan::copy_register_flags(Interval* from, Interval* to) {
299 if (gen()->is_vreg_flag_set(from->reg_num(), LIRGenerator::byte_reg)) {
300 gen()->set_vreg_flag(to->reg_num(), LIRGenerator::byte_reg);
301 }
302 if (gen()->is_vreg_flag_set(from->reg_num(), LIRGenerator::callee_saved)) {
303 gen()->set_vreg_flag(to->reg_num(), LIRGenerator::callee_saved);
304 }
305
306 // Note: do not copy the must_start_in_memory flag because it is not necessary for child
307 // intervals (only the very beginning of the interval must be in memory)
308 }
309
310
311 // ********** spill move optimization
312 // eliminate moves from register to stack if stack slot is known to be correct
313
314 // called during building of intervals
315 void LinearScan::change_spill_definition_pos(Interval* interval, int def_pos) {
316 assert(interval->is_split_parent(), "can only be called for split parents");
317
318 switch (interval->spill_state()) {
319 case noDefinitionFound:
320 assert(interval->spill_definition_pos() == -1, "must no be set before");
321 interval->set_spill_definition_pos(def_pos);
322 interval->set_spill_state(oneDefinitionFound);
323 break;
324
325 case oneDefinitionFound:
326 assert(def_pos <= interval->spill_definition_pos(), "positions are processed in reverse order when intervals are created");
327 if (def_pos < interval->spill_definition_pos() - 2) {
328 // second definition found, so no spill optimization possible for this interval
329 interval->set_spill_state(noOptimization);
330 } else {
331 // two consecutive definitions (because of two-operand LIR form)
332 assert(block_of_op_with_id(def_pos) == block_of_op_with_id(interval->spill_definition_pos()), "block must be equal");
333 }
334 break;
335
336 case noOptimization:
337 // nothing to do
338 break;
339
340 default:
341 assert(false, "other states not allowed at this time");
342 }
343 }
344
345 // called during register allocation
346 void LinearScan::change_spill_state(Interval* interval, int spill_pos) {
347 switch (interval->spill_state()) {
348 case oneDefinitionFound: {
349 int def_loop_depth = block_of_op_with_id(interval->spill_definition_pos())->loop_depth();
350 int spill_loop_depth = block_of_op_with_id(spill_pos)->loop_depth();
351
352 if (def_loop_depth < spill_loop_depth) {
353 // the loop depth of the spilling position is higher then the loop depth
354 // at the definition of the interval -> move write to memory out of loop
355 // by storing at definitin of the interval
356 interval->set_spill_state(storeAtDefinition);
357 } else {
358 // the interval is currently spilled only once, so for now there is no
359 // reason to store the interval at the definition
360 interval->set_spill_state(oneMoveInserted);
361 }
362 break;
363 }
364
365 case oneMoveInserted: {
366 // the interval is spilled more then once, so it is better to store it to
367 // memory at the definition
368 interval->set_spill_state(storeAtDefinition);
369 break;
370 }
371
372 case storeAtDefinition:
373 case startInMemory:
374 case noOptimization:
375 case noDefinitionFound:
376 // nothing to do
377 break;
378
379 default:
380 assert(false, "other states not allowed at this time");
381 }
382 }
383
384
385 bool LinearScan::must_store_at_definition(const Interval* i) {
386 return i->is_split_parent() && i->spill_state() == storeAtDefinition;
387 }
388
389 // called once before asignment of register numbers
390 void LinearScan::eliminate_spill_moves() {
391 TIME_LINEAR_SCAN(timer_eliminate_spill_moves);
392 TRACE_LINEAR_SCAN(3, tty->print_cr("***** Eliminating unnecessary spill moves"));
393
394 // collect all intervals that must be stored after their definion.
395 // the list is sorted by Interval::spill_definition_pos
396 Interval* interval;
397 Interval* temp_list;
398 create_unhandled_lists(&interval, &temp_list, must_store_at_definition, NULL);
399
400 #ifdef ASSERT
401 Interval* prev = NULL;
402 Interval* temp = interval;
403 while (temp != Interval::end()) {
404 assert(temp->spill_definition_pos() > 0, "invalid spill definition pos");
405 if (prev != NULL) {
406 assert(temp->from() >= prev->from(), "intervals not sorted");
407 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");
408 }
409
410 assert(temp->canonical_spill_slot() >= LinearScan::nof_regs, "interval has no spill slot assigned");
411 assert(temp->spill_definition_pos() >= temp->from(), "invalid order");
412 assert(temp->spill_definition_pos() <= temp->from() + 2, "only intervals defined once at their start-pos can be optimized");
413
414 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()));
415
416 temp = temp->next();
417 }
418 #endif
419
420 LIR_InsertionBuffer insertion_buffer;
421 int num_blocks = block_count();
422 for (int i = 0; i < num_blocks; i++) {
423 BlockBegin* block = block_at(i);
424 LIR_OpList* instructions = block->lir()->instructions_list();
425 int num_inst = instructions->length();
426 bool has_new = false;
427
428 // iterate all instructions of the block. skip the first because it is always a label
429 for (int j = 1; j < num_inst; j++) {
430 LIR_Op* op = instructions->at(j);
431 int op_id = op->id();
432
433 if (op_id == -1) {
434 // remove move from register to stack if the stack slot is guaranteed to be correct.
435 // only moves that have been inserted by LinearScan can be removed.
436 assert(op->code() == lir_move, "only moves can have a op_id of -1");
437 assert(op->as_Op1() != NULL, "move must be LIR_Op1");
438 assert(op->as_Op1()->result_opr()->is_virtual(), "LinearScan inserts only moves to virtual registers");
439
440 LIR_Op1* op1 = (LIR_Op1*)op;
441 Interval* interval = interval_at(op1->result_opr()->vreg_number());
442
443 if (interval->assigned_reg() >= LinearScan::nof_regs && interval->always_in_memory()) {
444 // move target is a stack slot that is always correct, so eliminate instruction
445 TRACE_LINEAR_SCAN(4, tty->print_cr("eliminating move from interval %d to %d", op1->in_opr()->vreg_number(), op1->result_opr()->vreg_number()));
446 instructions->at_put(j, NULL); // NULL-instructions are deleted by assign_reg_num
447 }
448
449 } else {
450 // insert move from register to stack just after the beginning of the interval
451 assert(interval == Interval::end() || interval->spill_definition_pos() >= op_id, "invalid order");
452 assert(interval == Interval::end() || (interval->is_split_parent() && interval->spill_state() == storeAtDefinition), "invalid interval");
453
454 while (interval != Interval::end() && interval->spill_definition_pos() == op_id) {
455 if (!has_new) {
456 // prepare insertion buffer (appended when all instructions of the block are processed)
457 insertion_buffer.init(block->lir());
458 has_new = true;
459 }
460
461 LIR_Opr from_opr = operand_for_interval(interval);
462 LIR_Opr to_opr = canonical_spill_opr(interval);
463 assert(from_opr->is_fixed_cpu() || from_opr->is_fixed_fpu(), "from operand must be a register");
464 assert(to_opr->is_stack(), "to operand must be a stack slot");
465
466 insertion_buffer.move(j, from_opr, to_opr);
467 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));
468
469 interval = interval->next();
470 }
471 }
472 } // end of instruction iteration
473
474 if (has_new) {
475 block->lir()->append(&insertion_buffer);
476 }
477 } // end of block iteration
478
479 assert(interval == Interval::end(), "missed an interval");
480 }
481
482
483 // ********** Phase 1: number all instructions in all blocks
484 // Compute depth-first and linear scan block orders, and number LIR_Op nodes for linear scan.
485
486 void LinearScan::number_instructions() {
487 {
488 // dummy-timer to measure the cost of the timer itself
489 // (this time is then subtracted from all other timers to get the real value)
490 TIME_LINEAR_SCAN(timer_do_nothing);
491 }
492 TIME_LINEAR_SCAN(timer_number_instructions);
493
494 // Assign IDs to LIR nodes and build a mapping, lir_ops, from ID to LIR_Op node.
495 int num_blocks = block_count();
496 int num_instructions = 0;
497 int i;
498 for (i = 0; i < num_blocks; i++) {
499 num_instructions += block_at(i)->lir()->instructions_list()->length();
500 }
501
502 // initialize with correct length
503 _lir_ops = LIR_OpArray(num_instructions, num_instructions, NULL);
504 _block_of_op = BlockBeginArray(num_instructions, num_instructions, NULL);
505
506 int op_id = 0;
507 int idx = 0;
508
509 for (i = 0; i < num_blocks; i++) {
510 BlockBegin* block = block_at(i);
511 block->set_first_lir_instruction_id(op_id);
512 LIR_OpList* instructions = block->lir()->instructions_list();
513
514 int num_inst = instructions->length();
515 for (int j = 0; j < num_inst; j++) {
516 LIR_Op* op = instructions->at(j);
517 op->set_id(op_id);
518
519 _lir_ops.at_put(idx, op);
520 _block_of_op.at_put(idx, block);
521 assert(lir_op_with_id(op_id) == op, "must match");
522
523 idx++;
524 op_id += 2; // numbering of lir_ops by two
525 }
526 block->set_last_lir_instruction_id(op_id - 2);
527 }
528 assert(idx == num_instructions, "must match");
529 assert(idx * 2 == op_id, "must match");
530
531 _has_call.initialize(num_instructions);
532 _has_info.initialize(num_instructions);
533 }
534
535
536 // ********** Phase 2: compute local live sets separately for each block
537 // (sets live_gen and live_kill for each block)
538
539 void LinearScan::set_live_gen_kill(Value value, LIR_Op* op, BitMap& live_gen, BitMap& live_kill) {
540 LIR_Opr opr = value->operand();
541 Constant* con = value->as_Constant();
542
543 // check some asumptions about debug information
544 assert(!value->type()->is_illegal(), "if this local is used by the interpreter it shouldn't be of indeterminate type");
545 assert(con == NULL || opr->is_virtual() || opr->is_constant() || opr->is_illegal(), "asumption: Constant instructions have only constant operands");
546 assert(con != NULL || opr->is_virtual(), "asumption: non-Constant instructions have only virtual operands");
547
548 if ((con == NULL || con->is_pinned()) && opr->is_register()) {
549 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
550 int reg = opr->vreg_number();
551 if (!live_kill.at(reg)) {
552 live_gen.set_bit(reg);
553 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));
554 }
555 }
556 }
557
558
559 void LinearScan::compute_local_live_sets() {
560 TIME_LINEAR_SCAN(timer_compute_local_live_sets);
561
562 int num_blocks = block_count();
563 int live_size = live_set_size();
564 bool local_has_fpu_registers = false;
565 int local_num_calls = 0;
566 LIR_OpVisitState visitor;
567
568 BitMap2D local_interval_in_loop = BitMap2D(_num_virtual_regs, num_loops());
569
570 // iterate all blocks
571 for (int i = 0; i < num_blocks; i++) {
572 BlockBegin* block = block_at(i);
573
574 ResourceBitMap live_gen(live_size);
575 ResourceBitMap live_kill(live_size);
576
577 if (block->is_set(BlockBegin::exception_entry_flag)) {
578 // Phi functions at the begin of an exception handler are
579 // implicitly defined (= killed) at the beginning of the block.
580 for_each_phi_fun(block, phi,
581 if (!phi->is_illegal()) { live_kill.set_bit(phi->operand()->vreg_number()); }
582 );
583 }
584
585 LIR_OpList* instructions = block->lir()->instructions_list();
586 int num_inst = instructions->length();
587
588 // iterate all instructions of the block. skip the first because it is always a label
589 assert(visitor.no_operands(instructions->at(0)), "first operation must always be a label");
590 for (int j = 1; j < num_inst; j++) {
591 LIR_Op* op = instructions->at(j);
592
593 // visit operation to collect all operands
594 visitor.visit(op);
595
596 if (visitor.has_call()) {
597 _has_call.set_bit(op->id() >> 1);
598 local_num_calls++;
599 }
600 if (visitor.info_count() > 0) {
601 _has_info.set_bit(op->id() >> 1);
602 }
603
604 // iterate input operands of instruction
605 int k, n, reg;
606 n = visitor.opr_count(LIR_OpVisitState::inputMode);
607 for (k = 0; k < n; k++) {
608 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::inputMode, k);
609 assert(opr->is_register(), "visitor should only return register operands");
610
611 if (opr->is_virtual_register()) {
612 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
613 reg = opr->vreg_number();
614 if (!live_kill.at(reg)) {
615 live_gen.set_bit(reg);
616 TRACE_LINEAR_SCAN(4, tty->print_cr(" Setting live_gen for register %d at instruction %d", reg, op->id()));
617 }
618 if (block->loop_index() >= 0) {
619 local_interval_in_loop.set_bit(reg, block->loop_index());
620 }
621 local_has_fpu_registers = local_has_fpu_registers || opr->is_virtual_fpu();
622 }
623
624 #ifdef ASSERT
625 // fixed intervals are never live at block boundaries, so
626 // they need not be processed in live sets.
627 // this is checked by these assertions to be sure about it.
628 // the entry block may have incoming values in registers, which is ok.
629 if (!opr->is_virtual_register() && block != ir()->start()) {
630 reg = reg_num(opr);
631 if (is_processed_reg_num(reg)) {
632 assert(live_kill.at(reg), "using fixed register that is not defined in this block");
633 }
634 reg = reg_numHi(opr);
635 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
636 assert(live_kill.at(reg), "using fixed register that is not defined in this block");
637 }
638 }
639 #endif
640 }
641
642 // Add uses of live locals from interpreter's point of view for proper debug information generation
643 n = visitor.info_count();
644 for (k = 0; k < n; k++) {
645 CodeEmitInfo* info = visitor.info_at(k);
646 ValueStack* stack = info->stack();
647 for_each_state_value(stack, value,
648 set_live_gen_kill(value, op, live_gen, live_kill)
649 );
650 }
651
652 // iterate temp operands of instruction
653 n = visitor.opr_count(LIR_OpVisitState::tempMode);
654 for (k = 0; k < n; k++) {
655 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::tempMode, k);
656 assert(opr->is_register(), "visitor should only return register operands");
657
658 if (opr->is_virtual_register()) {
659 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
660 reg = opr->vreg_number();
661 live_kill.set_bit(reg);
662 if (block->loop_index() >= 0) {
663 local_interval_in_loop.set_bit(reg, block->loop_index());
664 }
665 local_has_fpu_registers = local_has_fpu_registers || opr->is_virtual_fpu();
666 }
667
668 #ifdef ASSERT
669 // fixed intervals are never live at block boundaries, so
670 // they need not be processed in live sets
671 // process them only in debug mode so that this can be checked
672 if (!opr->is_virtual_register()) {
673 reg = reg_num(opr);
674 if (is_processed_reg_num(reg)) {
675 live_kill.set_bit(reg_num(opr));
676 }
677 reg = reg_numHi(opr);
678 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
679 live_kill.set_bit(reg);
680 }
681 }
682 #endif
683 }
684
685 // iterate output operands of instruction
686 n = visitor.opr_count(LIR_OpVisitState::outputMode);
687 for (k = 0; k < n; k++) {
688 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::outputMode, k);
689 assert(opr->is_register(), "visitor should only return register operands");
690
691 if (opr->is_virtual_register()) {
692 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
693 reg = opr->vreg_number();
694 live_kill.set_bit(reg);
695 if (block->loop_index() >= 0) {
696 local_interval_in_loop.set_bit(reg, block->loop_index());
697 }
698 local_has_fpu_registers = local_has_fpu_registers || opr->is_virtual_fpu();
699 }
700
701 #ifdef ASSERT
702 // fixed intervals are never live at block boundaries, so
703 // they need not be processed in live sets
704 // process them only in debug mode so that this can be checked
705 if (!opr->is_virtual_register()) {
706 reg = reg_num(opr);
707 if (is_processed_reg_num(reg)) {
708 live_kill.set_bit(reg_num(opr));
709 }
710 reg = reg_numHi(opr);
711 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
712 live_kill.set_bit(reg);
713 }
714 }
715 #endif
716 }
717 } // end of instruction iteration
718
719 block->set_live_gen (live_gen);
720 block->set_live_kill(live_kill);
721 block->set_live_in (ResourceBitMap(live_size));
722 block->set_live_out (ResourceBitMap(live_size));
723
724 TRACE_LINEAR_SCAN(4, tty->print("live_gen B%d ", block->block_id()); print_bitmap(block->live_gen()));
725 TRACE_LINEAR_SCAN(4, tty->print("live_kill B%d ", block->block_id()); print_bitmap(block->live_kill()));
726 } // end of block iteration
727
728 // propagate local calculated information into LinearScan object
729 _has_fpu_registers = local_has_fpu_registers;
730 compilation()->set_has_fpu_code(local_has_fpu_registers);
731
732 _num_calls = local_num_calls;
733 _interval_in_loop = local_interval_in_loop;
734 }
735
736
737 // ********** Phase 3: perform a backward dataflow analysis to compute global live sets
738 // (sets live_in and live_out for each block)
739
740 void LinearScan::compute_global_live_sets() {
741 TIME_LINEAR_SCAN(timer_compute_global_live_sets);
742
743 int num_blocks = block_count();
744 bool change_occurred;
745 bool change_occurred_in_block;
746 int iteration_count = 0;
747 ResourceBitMap live_out(live_set_size()); // scratch set for calculations
748
749 // Perform a backward dataflow analysis to compute live_out and live_in for each block.
750 // The loop is executed until a fixpoint is reached (no changes in an iteration)
751 // Exception handlers must be processed because not all live values are
752 // present in the state array, e.g. because of global value numbering
753 do {
754 change_occurred = false;
755
756 // iterate all blocks in reverse order
757 for (int i = num_blocks - 1; i >= 0; i--) {
758 BlockBegin* block = block_at(i);
759
760 change_occurred_in_block = false;
761
762 // live_out(block) is the union of live_in(sux), for successors sux of block
763 int n = block->number_of_sux();
764 int e = block->number_of_exception_handlers();
765 if (n + e > 0) {
766 // block has successors
767 if (n > 0) {
768 live_out.set_from(block->sux_at(0)->live_in());
769 for (int j = 1; j < n; j++) {
770 live_out.set_union(block->sux_at(j)->live_in());
771 }
772 } else {
773 live_out.clear();
774 }
775 for (int j = 0; j < e; j++) {
776 live_out.set_union(block->exception_handler_at(j)->live_in());
777 }
778
779 if (!block->live_out().is_same(live_out)) {
780 // A change occurred. Swap the old and new live out sets to avoid copying.
781 ResourceBitMap temp = block->live_out();
782 block->set_live_out(live_out);
783 live_out = temp;
784
785 change_occurred = true;
786 change_occurred_in_block = true;
787 }
788 }
789
790 if (iteration_count == 0 || change_occurred_in_block) {
791 // live_in(block) is the union of live_gen(block) with (live_out(block) & !live_kill(block))
792 // note: live_in has to be computed only in first iteration or if live_out has changed!
793 ResourceBitMap live_in = block->live_in();
794 live_in.set_from(block->live_out());
795 live_in.set_difference(block->live_kill());
796 live_in.set_union(block->live_gen());
797 }
798
799 #ifndef PRODUCT
800 if (TraceLinearScanLevel >= 4) {
801 char c = ' ';
802 if (iteration_count == 0 || change_occurred_in_block) {
803 c = '*';
804 }
805 tty->print("(%d) live_in%c B%d ", iteration_count, c, block->block_id()); print_bitmap(block->live_in());
806 tty->print("(%d) live_out%c B%d ", iteration_count, c, block->block_id()); print_bitmap(block->live_out());
807 }
808 #endif
809 }
810 iteration_count++;
811
812 if (change_occurred && iteration_count > 50) {
813 BAILOUT("too many iterations in compute_global_live_sets");
814 }
815 } while (change_occurred);
816
817
818 #ifdef ASSERT
819 // check that fixed intervals are not live at block boundaries
820 // (live set must be empty at fixed intervals)
821 for (int i = 0; i < num_blocks; i++) {
822 BlockBegin* block = block_at(i);
823 for (int j = 0; j < LIR_OprDesc::vreg_base; j++) {
824 assert(block->live_in().at(j) == false, "live_in set of fixed register must be empty");
825 assert(block->live_out().at(j) == false, "live_out set of fixed register must be empty");
826 assert(block->live_gen().at(j) == false, "live_gen set of fixed register must be empty");
827 }
828 }
829 #endif
830
831 // check that the live_in set of the first block is empty
832 ResourceBitMap live_in_args(ir()->start()->live_in().size());
833 if (!ir()->start()->live_in().is_same(live_in_args)) {
834 #ifdef ASSERT
835 tty->print_cr("Error: live_in set of first block must be empty (when this fails, virtual registers are used before they are defined)");
836 tty->print_cr("affected registers:");
837 print_bitmap(ir()->start()->live_in());
838
839 // print some additional information to simplify debugging
840 for (unsigned int i = 0; i < ir()->start()->live_in().size(); i++) {
841 if (ir()->start()->live_in().at(i)) {
842 Instruction* instr = gen()->instruction_for_vreg(i);
843 tty->print_cr("* vreg %d (HIR instruction %c%d)", i, instr == NULL ? ' ' : instr->type()->tchar(), instr == NULL ? 0 : instr->id());
844
845 for (int j = 0; j < num_blocks; j++) {
846 BlockBegin* block = block_at(j);
847 if (block->live_gen().at(i)) {
848 tty->print_cr(" used in block B%d", block->block_id());
849 }
850 if (block->live_kill().at(i)) {
851 tty->print_cr(" defined in block B%d", block->block_id());
852 }
853 }
854 }
855 }
856
857 #endif
858 // when this fails, virtual registers are used before they are defined.
859 assert(false, "live_in set of first block must be empty");
860 // bailout of if this occurs in product mode.
861 bailout("live_in set of first block not empty");
862 }
863 }
864
865
866 // ********** Phase 4: build intervals
867 // (fills the list _intervals)
868
869 void LinearScan::add_use(Value value, int from, int to, IntervalUseKind use_kind) {
870 assert(!value->type()->is_illegal(), "if this value is used by the interpreter it shouldn't be of indeterminate type");
871 LIR_Opr opr = value->operand();
872 Constant* con = value->as_Constant();
873
874 if ((con == NULL || con->is_pinned()) && opr->is_register()) {
875 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
876 add_use(opr, from, to, use_kind);
877 }
878 }
879
880
881 void LinearScan::add_def(LIR_Opr opr, int def_pos, IntervalUseKind use_kind) {
882 TRACE_LINEAR_SCAN(2, tty->print(" def "); opr->print(tty); tty->print_cr(" def_pos %d (%d)", def_pos, use_kind));
883 assert(opr->is_register(), "should not be called otherwise");
884
885 if (opr->is_virtual_register()) {
886 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
887 add_def(opr->vreg_number(), def_pos, use_kind, opr->type_register());
888
889 } else {
890 int reg = reg_num(opr);
891 if (is_processed_reg_num(reg)) {
892 add_def(reg, def_pos, use_kind, opr->type_register());
893 }
894 reg = reg_numHi(opr);
895 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
896 add_def(reg, def_pos, use_kind, opr->type_register());
897 }
898 }
899 }
900
901 void LinearScan::add_use(LIR_Opr opr, int from, int to, IntervalUseKind use_kind) {
902 TRACE_LINEAR_SCAN(2, tty->print(" use "); opr->print(tty); tty->print_cr(" from %d to %d (%d)", from, to, use_kind));
903 assert(opr->is_register(), "should not be called otherwise");
904
905 if (opr->is_virtual_register()) {
906 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
907 add_use(opr->vreg_number(), from, to, use_kind, opr->type_register());
908
909 } else {
910 int reg = reg_num(opr);
911 if (is_processed_reg_num(reg)) {
912 add_use(reg, from, to, use_kind, opr->type_register());
913 }
914 reg = reg_numHi(opr);
915 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
916 add_use(reg, from, to, use_kind, opr->type_register());
917 }
918 }
919 }
920
921 void LinearScan::add_temp(LIR_Opr opr, int temp_pos, IntervalUseKind use_kind) {
922 TRACE_LINEAR_SCAN(2, tty->print(" temp "); opr->print(tty); tty->print_cr(" temp_pos %d (%d)", temp_pos, use_kind));
923 assert(opr->is_register(), "should not be called otherwise");
924
925 if (opr->is_virtual_register()) {
926 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
927 add_temp(opr->vreg_number(), temp_pos, use_kind, opr->type_register());
928
929 } else {
930 int reg = reg_num(opr);
931 if (is_processed_reg_num(reg)) {
932 add_temp(reg, temp_pos, use_kind, opr->type_register());
933 }
934 reg = reg_numHi(opr);
935 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
936 add_temp(reg, temp_pos, use_kind, opr->type_register());
937 }
938 }
939 }
940
941
942 void LinearScan::add_def(int reg_num, int def_pos, IntervalUseKind use_kind, BasicType type) {
943 Interval* interval = interval_at(reg_num);
944 if (interval != NULL) {
945 assert(interval->reg_num() == reg_num, "wrong interval");
946
947 if (type != T_ILLEGAL) {
948 interval->set_type(type);
949 }
950
951 Range* r = interval->first();
952 if (r->from() <= def_pos) {
953 // Update the starting point (when a range is first created for a use, its
954 // start is the beginning of the current block until a def is encountered.)
955 r->set_from(def_pos);
956 interval->add_use_pos(def_pos, use_kind);
957
958 } else {
959 // Dead value - make vacuous interval
960 // also add use_kind for dead intervals
961 interval->add_range(def_pos, def_pos + 1);
962 interval->add_use_pos(def_pos, use_kind);
963 TRACE_LINEAR_SCAN(2, tty->print_cr("Warning: def of reg %d at %d occurs without use", reg_num, def_pos));
964 }
965
966 } else {
967 // Dead value - make vacuous interval
968 // also add use_kind for dead intervals
969 interval = create_interval(reg_num);
970 if (type != T_ILLEGAL) {
971 interval->set_type(type);
972 }
973
974 interval->add_range(def_pos, def_pos + 1);
975 interval->add_use_pos(def_pos, use_kind);
976 TRACE_LINEAR_SCAN(2, tty->print_cr("Warning: dead value %d at %d in live intervals", reg_num, def_pos));
977 }
978
979 change_spill_definition_pos(interval, def_pos);
980 if (use_kind == noUse && interval->spill_state() <= startInMemory) {
981 // detection of method-parameters and roundfp-results
982 // TODO: move this directly to position where use-kind is computed
983 interval->set_spill_state(startInMemory);
984 }
985 }
986
987 void LinearScan::add_use(int reg_num, int from, int to, IntervalUseKind use_kind, BasicType type) {
988 Interval* interval = interval_at(reg_num);
989 if (interval == NULL) {
990 interval = create_interval(reg_num);
991 }
992 assert(interval->reg_num() == reg_num, "wrong interval");
993
994 if (type != T_ILLEGAL) {
995 interval->set_type(type);
996 }
997
998 interval->add_range(from, to);
999 interval->add_use_pos(to, use_kind);
1000 }
1001
1002 void LinearScan::add_temp(int reg_num, int temp_pos, IntervalUseKind use_kind, BasicType type) {
1003 Interval* interval = interval_at(reg_num);
1004 if (interval == NULL) {
1005 interval = create_interval(reg_num);
1006 }
1007 assert(interval->reg_num() == reg_num, "wrong interval");
1008
1009 if (type != T_ILLEGAL) {
1010 interval->set_type(type);
1011 }
1012
1013 interval->add_range(temp_pos, temp_pos + 1);
1014 interval->add_use_pos(temp_pos, use_kind);
1015 }
1016
1017
1018 // the results of this functions are used for optimizing spilling and reloading
1019 // if the functions return shouldHaveRegister and the interval is spilled,
1020 // it is not reloaded to a register.
1021 IntervalUseKind LinearScan::use_kind_of_output_operand(LIR_Op* op, LIR_Opr opr) {
1022 if (op->code() == lir_move) {
1023 assert(op->as_Op1() != NULL, "lir_move must be LIR_Op1");
1024 LIR_Op1* move = (LIR_Op1*)op;
1025 LIR_Opr res = move->result_opr();
1026 bool result_in_memory = res->is_virtual() && gen()->is_vreg_flag_set(res->vreg_number(), LIRGenerator::must_start_in_memory);
1027
1028 if (result_in_memory) {
1029 // Begin of an interval with must_start_in_memory set.
1030 // This interval will always get a stack slot first, so return noUse.
1031 return noUse;
1032
1033 } else if (move->in_opr()->is_stack()) {
1034 // method argument (condition must be equal to handle_method_arguments)
1035 return noUse;
1036
1037 } else if (move->in_opr()->is_register() && move->result_opr()->is_register()) {
1038 // Move from register to register
1039 if (block_of_op_with_id(op->id())->is_set(BlockBegin::osr_entry_flag)) {
1040 // special handling of phi-function moves inside osr-entry blocks
1041 // input operand must have a register instead of output operand (leads to better register allocation)
1042 return shouldHaveRegister;
1043 }
1044 }
1045 }
1046
1047 if (opr->is_virtual() &&
1048 gen()->is_vreg_flag_set(opr->vreg_number(), LIRGenerator::must_start_in_memory)) {
1049 // result is a stack-slot, so prevent immediate reloading
1050 return noUse;
1051 }
1052
1053 // all other operands require a register
1054 return mustHaveRegister;
1055 }
1056
1057 IntervalUseKind LinearScan::use_kind_of_input_operand(LIR_Op* op, LIR_Opr opr) {
1058 if (op->code() == lir_move) {
1059 assert(op->as_Op1() != NULL, "lir_move must be LIR_Op1");
1060 LIR_Op1* move = (LIR_Op1*)op;
1061 LIR_Opr res = move->result_opr();
1062 bool result_in_memory = res->is_virtual() && gen()->is_vreg_flag_set(res->vreg_number(), LIRGenerator::must_start_in_memory);
1063
1064 if (result_in_memory) {
1065 // Move to an interval with must_start_in_memory set.
1066 // To avoid moves from stack to stack (not allowed) force the input operand to a register
1067 return mustHaveRegister;
1068
1069 } else if (move->in_opr()->is_register() && move->result_opr()->is_register()) {
1070 // Move from register to register
1071 if (block_of_op_with_id(op->id())->is_set(BlockBegin::osr_entry_flag)) {
1072 // special handling of phi-function moves inside osr-entry blocks
1073 // input operand must have a register instead of output operand (leads to better register allocation)
1074 return mustHaveRegister;
1075 }
1076
1077 // The input operand is not forced to a register (moves from stack to register are allowed),
1078 // but it is faster if the input operand is in a register
1079 return shouldHaveRegister;
1080 }
1081 }
1082
1083
1084 #if defined(X86) || defined(S390)
1085 if (op->code() == lir_cmove) {
1086 // conditional moves can handle stack operands
1087 assert(op->result_opr()->is_register(), "result must always be in a register");
1088 return shouldHaveRegister;
1089 }
1090
1091 // optimizations for second input operand of arithmehtic operations on Intel
1092 // this operand is allowed to be on the stack in some cases
1093 BasicType opr_type = opr->type_register();
1094 if (opr_type == T_FLOAT || opr_type == T_DOUBLE) {
1095 if (IA32_ONLY( (UseSSE == 1 && opr_type == T_FLOAT) || UseSSE >= 2 ) NOT_IA32( true )) {
1096 // SSE float instruction (T_DOUBLE only supported with SSE2)
1097 switch (op->code()) {
1098 case lir_cmp:
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 default:
1112 break;
1113 }
1114 } else {
1115 // FPU stack float instruction
1116 switch (op->code()) {
1117 case lir_add:
1118 case lir_sub:
1119 case lir_mul:
1120 case lir_div:
1121 {
1122 assert(op->as_Op2() != NULL, "must be LIR_Op2");
1123 LIR_Op2* op2 = (LIR_Op2*)op;
1124 if (op2->in_opr1() != op2->in_opr2() && op2->in_opr2() == opr) {
1125 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");
1126 return shouldHaveRegister;
1127 }
1128 }
1129 default:
1130 break;
1131 }
1132 }
1133 // We want to sometimes use logical operations on pointers, in particular in GC barriers.
1134 // Since 64bit logical operations do not current support operands on stack, we have to make sure
1135 // T_OBJECT doesn't get spilled along with T_LONG.
1136 } else if (opr_type != T_LONG LP64_ONLY(&& opr_type != T_OBJECT)) {
1137 // integer instruction (note: long operands must always be in register)
1138 switch (op->code()) {
1139 case lir_cmp:
1140 case lir_add:
1141 case lir_sub:
1142 case lir_logic_and:
1143 case lir_logic_or:
1144 case lir_logic_xor:
1145 {
1146 assert(op->as_Op2() != NULL, "must be LIR_Op2");
1147 LIR_Op2* op2 = (LIR_Op2*)op;
1148 if (op2->in_opr1() != op2->in_opr2() && op2->in_opr2() == opr) {
1149 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");
1150 return shouldHaveRegister;
1151 }
1152 }
1153 default:
1154 break;
1155 }
1156 }
1157 #endif // X86 || S390
1158
1159 // all other operands require a register
1160 return mustHaveRegister;
1161 }
1162
1163
1164 void LinearScan::handle_method_arguments(LIR_Op* op) {
1165 // special handling for method arguments (moves from stack to virtual register):
1166 // the interval gets no register assigned, but the stack slot.
1167 // it is split before the first use by the register allocator.
1168
1169 if (op->code() == lir_move) {
1170 assert(op->as_Op1() != NULL, "must be LIR_Op1");
1171 LIR_Op1* move = (LIR_Op1*)op;
1172
1173 if (move->in_opr()->is_stack()) {
1174 #ifdef ASSERT
1175 int arg_size = compilation()->method()->arg_size();
1176 LIR_Opr o = move->in_opr();
1177 if (o->is_single_stack()) {
1178 assert(o->single_stack_ix() >= 0 && o->single_stack_ix() < arg_size, "out of range");
1179 } else if (o->is_double_stack()) {
1180 assert(o->double_stack_ix() >= 0 && o->double_stack_ix() < arg_size, "out of range");
1181 } else {
1182 ShouldNotReachHere();
1183 }
1184
1185 assert(move->id() > 0, "invalid id");
1186 assert(block_of_op_with_id(move->id())->number_of_preds() == 0, "move from stack must be in first block");
1187 assert(move->result_opr()->is_virtual(), "result of move must be a virtual register");
1188
1189 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())));
1190 #endif
1191
1192 Interval* interval = interval_at(reg_num(move->result_opr()));
1193
1194 int stack_slot = LinearScan::nof_regs + (move->in_opr()->is_single_stack() ? move->in_opr()->single_stack_ix() : move->in_opr()->double_stack_ix());
1195 interval->set_canonical_spill_slot(stack_slot);
1196 interval->assign_reg(stack_slot);
1197 }
1198 }
1199 }
1200
1201 void LinearScan::handle_doubleword_moves(LIR_Op* op) {
1202 // special handling for doubleword move from memory to register:
1203 // in this case the registers of the input address and the result
1204 // registers must not overlap -> add a temp range for the input registers
1205 if (op->code() == lir_move) {
1206 assert(op->as_Op1() != NULL, "must be LIR_Op1");
1207 LIR_Op1* move = (LIR_Op1*)op;
1208
1209 if (move->result_opr()->is_double_cpu() && move->in_opr()->is_pointer()) {
1210 LIR_Address* address = move->in_opr()->as_address_ptr();
1211 if (address != NULL) {
1212 if (address->base()->is_valid()) {
1213 add_temp(address->base(), op->id(), noUse);
1214 }
1215 if (address->index()->is_valid()) {
1216 add_temp(address->index(), op->id(), noUse);
1217 }
1218 }
1219 }
1220 }
1221 }
1222
1223 void LinearScan::add_register_hints(LIR_Op* op) {
1224 switch (op->code()) {
1225 case lir_move: // fall through
1226 case lir_convert: {
1227 assert(op->as_Op1() != NULL, "lir_move, lir_convert must be LIR_Op1");
1228 LIR_Op1* move = (LIR_Op1*)op;
1229
1230 LIR_Opr move_from = move->in_opr();
1231 LIR_Opr move_to = move->result_opr();
1232
1233 if (move_to->is_register() && move_from->is_register()) {
1234 Interval* from = interval_at(reg_num(move_from));
1235 Interval* to = interval_at(reg_num(move_to));
1236 if (from != NULL && to != NULL) {
1237 to->set_register_hint(from);
1238 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()));
1239 }
1240 }
1241 break;
1242 }
1243 case lir_cmove: {
1244 assert(op->as_Op2() != NULL, "lir_cmove must be LIR_Op2");
1245 LIR_Op2* cmove = (LIR_Op2*)op;
1246
1247 LIR_Opr move_from = cmove->in_opr1();
1248 LIR_Opr move_to = cmove->result_opr();
1249
1250 if (move_to->is_register() && move_from->is_register()) {
1251 Interval* from = interval_at(reg_num(move_from));
1252 Interval* to = interval_at(reg_num(move_to));
1253 if (from != NULL && to != NULL) {
1254 to->set_register_hint(from);
1255 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()));
1256 }
1257 }
1258 break;
1259 }
1260 default:
1261 break;
1262 }
1263 }
1264
1265
1266 void LinearScan::build_intervals() {
1267 TIME_LINEAR_SCAN(timer_build_intervals);
1268
1269 // initialize interval list with expected number of intervals
1270 // (32 is added to have some space for split children without having to resize the list)
1271 _intervals = IntervalList(num_virtual_regs() + 32);
1272 // initialize all slots that are used by build_intervals
1273 _intervals.at_put_grow(num_virtual_regs() - 1, NULL, NULL);
1274
1275 // create a list with all caller-save registers (cpu, fpu, xmm)
1276 // when an instruction is a call, a temp range is created for all these registers
1277 int num_caller_save_registers = 0;
1278 int caller_save_registers[LinearScan::nof_regs];
1279
1280 int i;
1281 for (i = 0; i < FrameMap::nof_caller_save_cpu_regs(); i++) {
1282 LIR_Opr opr = FrameMap::caller_save_cpu_reg_at(i);
1283 assert(opr->is_valid() && opr->is_register(), "FrameMap should not return invalid operands");
1284 assert(reg_numHi(opr) == -1, "missing addition of range for hi-register");
1285 caller_save_registers[num_caller_save_registers++] = reg_num(opr);
1286 }
1287
1288 // temp ranges for fpu registers are only created when the method has
1289 // virtual fpu operands. Otherwise no allocation for fpu registers is
1290 // performed and so the temp ranges would be useless
1291 if (has_fpu_registers()) {
1292 #ifdef IA32
1293 if (UseSSE < 2) {
1294 #endif // IA32
1295 for (i = 0; i < FrameMap::nof_caller_save_fpu_regs; i++) {
1296 LIR_Opr opr = FrameMap::caller_save_fpu_reg_at(i);
1297 assert(opr->is_valid() && opr->is_register(), "FrameMap should not return invalid operands");
1298 assert(reg_numHi(opr) == -1, "missing addition of range for hi-register");
1299 caller_save_registers[num_caller_save_registers++] = reg_num(opr);
1300 }
1301 #ifdef IA32
1302 }
1303 #endif// IA32
1304
1305 #ifdef X86
1306 if (UseSSE > 0) {
1307 int num_caller_save_xmm_regs = FrameMap::get_num_caller_save_xmms();
1308 for (i = 0; i < num_caller_save_xmm_regs; i ++) {
1309 LIR_Opr opr = FrameMap::caller_save_xmm_reg_at(i);
1310 assert(opr->is_valid() && opr->is_register(), "FrameMap should not return invalid operands");
1311 assert(reg_numHi(opr) == -1, "missing addition of range for hi-register");
1312 caller_save_registers[num_caller_save_registers++] = reg_num(opr);
1313 }
1314 }
1315 #endif // X86
1316 }
1317 assert(num_caller_save_registers <= LinearScan::nof_regs, "out of bounds");
1318
1319
1320 LIR_OpVisitState visitor;
1321
1322 // iterate all blocks in reverse order
1323 for (i = block_count() - 1; i >= 0; i--) {
1324 BlockBegin* block = block_at(i);
1325 LIR_OpList* instructions = block->lir()->instructions_list();
1326 int block_from = block->first_lir_instruction_id();
1327 int block_to = block->last_lir_instruction_id();
1328
1329 assert(block_from == instructions->at(0)->id(), "must be");
1330 assert(block_to == instructions->at(instructions->length() - 1)->id(), "must be");
1331
1332 // Update intervals for registers live at the end of this block;
1333 ResourceBitMap live = block->live_out();
1334 int size = (int)live.size();
1335 for (int number = (int)live.get_next_one_offset(0, size); number < size; number = (int)live.get_next_one_offset(number + 1, size)) {
1336 assert(live.at(number), "should not stop here otherwise");
1337 assert(number >= LIR_OprDesc::vreg_base, "fixed intervals must not be live on block bounds");
1338 TRACE_LINEAR_SCAN(2, tty->print_cr("live in %d to %d", number, block_to + 2));
1339
1340 add_use(number, block_from, block_to + 2, noUse, T_ILLEGAL);
1341
1342 // add special use positions for loop-end blocks when the
1343 // interval is used anywhere inside this loop. It's possible
1344 // that the block was part of a non-natural loop, so it might
1345 // have an invalid loop index.
1346 if (block->is_set(BlockBegin::linear_scan_loop_end_flag) &&
1347 block->loop_index() != -1 &&
1348 is_interval_in_loop(number, block->loop_index())) {
1349 interval_at(number)->add_use_pos(block_to + 1, loopEndMarker);
1350 }
1351 }
1352
1353 // iterate all instructions of the block in reverse order.
1354 // skip the first instruction because it is always a label
1355 // definitions of intervals are processed before uses
1356 assert(visitor.no_operands(instructions->at(0)), "first operation must always be a label");
1357 for (int j = instructions->length() - 1; j >= 1; j--) {
1358 LIR_Op* op = instructions->at(j);
1359 int op_id = op->id();
1360
1361 // visit operation to collect all operands
1362 visitor.visit(op);
1363
1364 // add a temp range for each register if operation destroys caller-save registers
1365 if (visitor.has_call()) {
1366 for (int k = 0; k < num_caller_save_registers; k++) {
1367 add_temp(caller_save_registers[k], op_id, noUse, T_ILLEGAL);
1368 }
1369 TRACE_LINEAR_SCAN(4, tty->print_cr("operation destroys all caller-save registers"));
1370 }
1371
1372 // Add any platform dependent temps
1373 pd_add_temps(op);
1374
1375 // visit definitions (output and temp operands)
1376 int k, n;
1377 n = visitor.opr_count(LIR_OpVisitState::outputMode);
1378 for (k = 0; k < n; k++) {
1379 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::outputMode, k);
1380 assert(opr->is_register(), "visitor should only return register operands");
1381 add_def(opr, op_id, use_kind_of_output_operand(op, opr));
1382 }
1383
1384 n = visitor.opr_count(LIR_OpVisitState::tempMode);
1385 for (k = 0; k < n; k++) {
1386 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::tempMode, k);
1387 assert(opr->is_register(), "visitor should only return register operands");
1388 add_temp(opr, op_id, mustHaveRegister);
1389 }
1390
1391 // visit uses (input operands)
1392 n = visitor.opr_count(LIR_OpVisitState::inputMode);
1393 for (k = 0; k < n; k++) {
1394 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::inputMode, k);
1395 assert(opr->is_register(), "visitor should only return register operands");
1396 add_use(opr, block_from, op_id, use_kind_of_input_operand(op, opr));
1397 }
1398
1399 // Add uses of live locals from interpreter's point of view for proper
1400 // debug information generation
1401 // Treat these operands as temp values (if the life range is extended
1402 // to a call site, the value would be in a register at the call otherwise)
1403 n = visitor.info_count();
1404 for (k = 0; k < n; k++) {
1405 CodeEmitInfo* info = visitor.info_at(k);
1406 ValueStack* stack = info->stack();
1407 for_each_state_value(stack, value,
1408 add_use(value, block_from, op_id + 1, noUse);
1409 );
1410 }
1411
1412 // special steps for some instructions (especially moves)
1413 handle_method_arguments(op);
1414 handle_doubleword_moves(op);
1415 add_register_hints(op);
1416
1417 } // end of instruction iteration
1418 } // end of block iteration
1419
1420
1421 // add the range [0, 1[ to all fixed intervals
1422 // -> the register allocator need not handle unhandled fixed intervals
1423 for (int n = 0; n < LinearScan::nof_regs; n++) {
1424 Interval* interval = interval_at(n);
1425 if (interval != NULL) {
1426 interval->add_range(0, 1);
1427 }
1428 }
1429 }
1430
1431
1432 // ********** Phase 5: actual register allocation
1433
1434 int LinearScan::interval_cmp(Interval** a, Interval** b) {
1435 if (*a != NULL) {
1436 if (*b != NULL) {
1437 return (*a)->from() - (*b)->from();
1438 } else {
1439 return -1;
1440 }
1441 } else {
1442 if (*b != NULL) {
1443 return 1;
1444 } else {
1445 return 0;
1446 }
1447 }
1448 }
1449
1450 #ifndef PRODUCT
1451 int interval_cmp(Interval* const& l, Interval* const& r) {
1452 return l->from() - r->from();
1453 }
1454
1455 bool find_interval(Interval* interval, IntervalArray* intervals) {
1456 bool found;
1457 int idx = intervals->find_sorted<Interval*, interval_cmp>(interval, found);
1458
1459 if (!found) {
1460 return false;
1461 }
1462
1463 int from = interval->from();
1464
1465 // The index we've found using binary search is pointing to an interval
1466 // that is defined in the same place as the interval we were looking for.
1467 // So now we have to look around that index and find exact interval.
1468 for (int i = idx; i >= 0; i--) {
1469 if (intervals->at(i) == interval) {
1470 return true;
1471 }
1472 if (intervals->at(i)->from() != from) {
1473 break;
1474 }
1475 }
1476
1477 for (int i = idx + 1; i < intervals->length(); i++) {
1478 if (intervals->at(i) == interval) {
1479 return true;
1480 }
1481 if (intervals->at(i)->from() != from) {
1482 break;
1483 }
1484 }
1485
1486 return false;
1487 }
1488
1489 bool LinearScan::is_sorted(IntervalArray* intervals) {
1490 int from = -1;
1491 int null_count = 0;
1492
1493 for (int i = 0; i < intervals->length(); i++) {
1494 Interval* it = intervals->at(i);
1495 if (it != NULL) {
1496 assert(from <= it->from(), "Intervals are unordered");
1497 from = it->from();
1498 } else {
1499 null_count++;
1500 }
1501 }
1502
1503 assert(null_count == 0, "Sorted intervals should not contain nulls");
1504
1505 null_count = 0;
1506
1507 for (int i = 0; i < interval_count(); i++) {
1508 Interval* interval = interval_at(i);
1509 if (interval != NULL) {
1510 assert(find_interval(interval, intervals), "Lists do not contain same intervals");
1511 } else {
1512 null_count++;
1513 }
1514 }
1515
1516 assert(interval_count() - null_count == intervals->length(),
1517 "Sorted list should contain the same amount of non-NULL intervals as unsorted list");
1518
1519 return true;
1520 }
1521 #endif
1522
1523 void LinearScan::add_to_list(Interval** first, Interval** prev, Interval* interval) {
1524 if (*prev != NULL) {
1525 (*prev)->set_next(interval);
1526 } else {
1527 *first = interval;
1528 }
1529 *prev = interval;
1530 }
1531
1532 void LinearScan::create_unhandled_lists(Interval** list1, Interval** list2, bool (is_list1)(const Interval* i), bool (is_list2)(const Interval* i)) {
1533 assert(is_sorted(_sorted_intervals), "interval list is not sorted");
1534
1535 *list1 = *list2 = Interval::end();
1536
1537 Interval* list1_prev = NULL;
1538 Interval* list2_prev = NULL;
1539 Interval* v;
1540
1541 const int n = _sorted_intervals->length();
1542 for (int i = 0; i < n; i++) {
1543 v = _sorted_intervals->at(i);
1544 if (v == NULL) continue;
1545
1546 if (is_list1(v)) {
1547 add_to_list(list1, &list1_prev, v);
1548 } else if (is_list2 == NULL || is_list2(v)) {
1549 add_to_list(list2, &list2_prev, v);
1550 }
1551 }
1552
1553 if (list1_prev != NULL) list1_prev->set_next(Interval::end());
1554 if (list2_prev != NULL) list2_prev->set_next(Interval::end());
1555
1556 assert(list1_prev == NULL || list1_prev->next() == Interval::end(), "linear list ends not with sentinel");
1557 assert(list2_prev == NULL || list2_prev->next() == Interval::end(), "linear list ends not with sentinel");
1558 }
1559
1560
1561 void LinearScan::sort_intervals_before_allocation() {
1562 TIME_LINEAR_SCAN(timer_sort_intervals_before);
1563
1564 if (_needs_full_resort) {
1565 // There is no known reason why this should occur but just in case...
1566 assert(false, "should never occur");
1567 // Re-sort existing interval list because an Interval::from() has changed
1568 _sorted_intervals->sort(interval_cmp);
1569 _needs_full_resort = false;
1570 }
1571
1572 IntervalList* unsorted_list = &_intervals;
1573 int unsorted_len = unsorted_list->length();
1574 int sorted_len = 0;
1575 int unsorted_idx;
1576 int sorted_idx = 0;
1577 int sorted_from_max = -1;
1578
1579 // calc number of items for sorted list (sorted list must not contain NULL values)
1580 for (unsorted_idx = 0; unsorted_idx < unsorted_len; unsorted_idx++) {
1581 if (unsorted_list->at(unsorted_idx) != NULL) {
1582 sorted_len++;
1583 }
1584 }
1585 IntervalArray* sorted_list = new IntervalArray(sorted_len, sorted_len, NULL);
1586
1587 // special sorting algorithm: the original interval-list is almost sorted,
1588 // only some intervals are swapped. So this is much faster than a complete QuickSort
1589 for (unsorted_idx = 0; unsorted_idx < unsorted_len; unsorted_idx++) {
1590 Interval* cur_interval = unsorted_list->at(unsorted_idx);
1591
1592 if (cur_interval != NULL) {
1593 int cur_from = cur_interval->from();
1594
1595 if (sorted_from_max <= cur_from) {
1596 sorted_list->at_put(sorted_idx++, cur_interval);
1597 sorted_from_max = cur_interval->from();
1598 } else {
1599 // the asumption that the intervals are already sorted failed,
1600 // so this interval must be sorted in manually
1601 int j;
1602 for (j = sorted_idx - 1; j >= 0 && cur_from < sorted_list->at(j)->from(); j--) {
1603 sorted_list->at_put(j + 1, sorted_list->at(j));
1604 }
1605 sorted_list->at_put(j + 1, cur_interval);
1606 sorted_idx++;
1607 }
1608 }
1609 }
1610 _sorted_intervals = sorted_list;
1611 assert(is_sorted(_sorted_intervals), "intervals unsorted");
1612 }
1613
1614 void LinearScan::sort_intervals_after_allocation() {
1615 TIME_LINEAR_SCAN(timer_sort_intervals_after);
1616
1617 if (_needs_full_resort) {
1618 // Re-sort existing interval list because an Interval::from() has changed
1619 _sorted_intervals->sort(interval_cmp);
1620 _needs_full_resort = false;
1621 }
1622
1623 IntervalArray* old_list = _sorted_intervals;
1624 IntervalList* new_list = _new_intervals_from_allocation;
1625 int old_len = old_list->length();
1626 int new_len = new_list == NULL ? 0 : new_list->length();
1627
1628 if (new_len == 0) {
1629 // no intervals have been added during allocation, so sorted list is already up to date
1630 assert(is_sorted(_sorted_intervals), "intervals unsorted");
1631 return;
1632 }
1633
1634 // conventional sort-algorithm for new intervals
1635 new_list->sort(interval_cmp);
1636
1637 // merge old and new list (both already sorted) into one combined list
1638 int combined_list_len = old_len + new_len;
1639 IntervalArray* combined_list = new IntervalArray(combined_list_len, combined_list_len, NULL);
1640 int old_idx = 0;
1641 int new_idx = 0;
1642
1643 while (old_idx + new_idx < old_len + new_len) {
1644 if (new_idx >= new_len || (old_idx < old_len && old_list->at(old_idx)->from() <= new_list->at(new_idx)->from())) {
1645 combined_list->at_put(old_idx + new_idx, old_list->at(old_idx));
1646 old_idx++;
1647 } else {
1648 combined_list->at_put(old_idx + new_idx, new_list->at(new_idx));
1649 new_idx++;
1650 }
1651 }
1652
1653 _sorted_intervals = combined_list;
1654 assert(is_sorted(_sorted_intervals), "intervals unsorted");
1655 }
1656
1657
1658 void LinearScan::allocate_registers() {
1659 TIME_LINEAR_SCAN(timer_allocate_registers);
1660
1661 Interval* precolored_cpu_intervals, *not_precolored_cpu_intervals;
1662 Interval* precolored_fpu_intervals, *not_precolored_fpu_intervals;
1663
1664 // allocate cpu registers
1665 create_unhandled_lists(&precolored_cpu_intervals, ¬_precolored_cpu_intervals,
1666 is_precolored_cpu_interval, is_virtual_cpu_interval);
1667
1668 // allocate fpu registers
1669 create_unhandled_lists(&precolored_fpu_intervals, ¬_precolored_fpu_intervals,
1670 is_precolored_fpu_interval, is_virtual_fpu_interval);
1671
1672 // the fpu interval allocation cannot be moved down below with the fpu section as
1673 // the cpu_lsw.walk() changes interval positions.
1674
1675 LinearScanWalker cpu_lsw(this, precolored_cpu_intervals, not_precolored_cpu_intervals);
1676 cpu_lsw.walk();
1677 cpu_lsw.finish_allocation();
1678
1679 if (has_fpu_registers()) {
1680 LinearScanWalker fpu_lsw(this, precolored_fpu_intervals, not_precolored_fpu_intervals);
1681 fpu_lsw.walk();
1682 fpu_lsw.finish_allocation();
1683 }
1684 }
1685
1686
1687 // ********** Phase 6: resolve data flow
1688 // (insert moves at edges between blocks if intervals have been split)
1689
1690 // wrapper for Interval::split_child_at_op_id that performs a bailout in product mode
1691 // instead of returning NULL
1692 Interval* LinearScan::split_child_at_op_id(Interval* interval, int op_id, LIR_OpVisitState::OprMode mode) {
1693 Interval* result = interval->split_child_at_op_id(op_id, mode);
1694 if (result != NULL) {
1695 return result;
1696 }
1697
1698 assert(false, "must find an interval, but do a clean bailout in product mode");
1699 result = new Interval(LIR_OprDesc::vreg_base);
1700 result->assign_reg(0);
1701 result->set_type(T_INT);
1702 BAILOUT_("LinearScan: interval is NULL", result);
1703 }
1704
1705
1706 Interval* LinearScan::interval_at_block_begin(BlockBegin* block, int reg_num) {
1707 assert(LinearScan::nof_regs <= reg_num && reg_num < num_virtual_regs(), "register number out of bounds");
1708 assert(interval_at(reg_num) != NULL, "no interval found");
1709
1710 return split_child_at_op_id(interval_at(reg_num), block->first_lir_instruction_id(), LIR_OpVisitState::outputMode);
1711 }
1712
1713 Interval* LinearScan::interval_at_block_end(BlockBegin* block, int reg_num) {
1714 assert(LinearScan::nof_regs <= reg_num && reg_num < num_virtual_regs(), "register number out of bounds");
1715 assert(interval_at(reg_num) != NULL, "no interval found");
1716
1717 return split_child_at_op_id(interval_at(reg_num), block->last_lir_instruction_id() + 1, LIR_OpVisitState::outputMode);
1718 }
1719
1720 Interval* LinearScan::interval_at_op_id(int reg_num, int op_id) {
1721 assert(LinearScan::nof_regs <= reg_num && reg_num < num_virtual_regs(), "register number out of bounds");
1722 assert(interval_at(reg_num) != NULL, "no interval found");
1723
1724 return split_child_at_op_id(interval_at(reg_num), op_id, LIR_OpVisitState::inputMode);
1725 }
1726
1727
1728 void LinearScan::resolve_collect_mappings(BlockBegin* from_block, BlockBegin* to_block, MoveResolver &move_resolver) {
1729 DEBUG_ONLY(move_resolver.check_empty());
1730
1731 const int size = live_set_size();
1732 const ResourceBitMap live_at_edge = to_block->live_in();
1733
1734 // visit all registers where the live_at_edge bit is set
1735 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)) {
1736 assert(r < num_virtual_regs(), "live information set for not exisiting interval");
1737 assert(from_block->live_out().at(r) && to_block->live_in().at(r), "interval not live at this edge");
1738
1739 Interval* from_interval = interval_at_block_end(from_block, r);
1740 Interval* to_interval = interval_at_block_begin(to_block, r);
1741
1742 if (from_interval != to_interval && (from_interval->assigned_reg() != to_interval->assigned_reg() || from_interval->assigned_regHi() != to_interval->assigned_regHi())) {
1743 // need to insert move instruction
1744 move_resolver.add_mapping(from_interval, to_interval);
1745 }
1746 }
1747 }
1748
1749
1750 void LinearScan::resolve_find_insert_pos(BlockBegin* from_block, BlockBegin* to_block, MoveResolver &move_resolver) {
1751 if (from_block->number_of_sux() <= 1) {
1752 TRACE_LINEAR_SCAN(4, tty->print_cr("inserting moves at end of from_block B%d", from_block->block_id()));
1753
1754 LIR_OpList* instructions = from_block->lir()->instructions_list();
1755 LIR_OpBranch* branch = instructions->last()->as_OpBranch();
1756 if (branch != NULL) {
1757 // insert moves before branch
1758 assert(branch->cond() == lir_cond_always, "block does not end with an unconditional jump");
1759 move_resolver.set_insert_position(from_block->lir(), instructions->length() - 2);
1760 } else {
1761 move_resolver.set_insert_position(from_block->lir(), instructions->length() - 1);
1762 }
1763
1764 } else {
1765 TRACE_LINEAR_SCAN(4, tty->print_cr("inserting moves at beginning of to_block B%d", to_block->block_id()));
1766 #ifdef ASSERT
1767 assert(from_block->lir()->instructions_list()->at(0)->as_OpLabel() != NULL, "block does not start with a label");
1768
1769 // because the number of predecessor edges matches the number of
1770 // successor edges, blocks which are reached by switch statements
1771 // may have be more than one predecessor but it will be guaranteed
1772 // that all predecessors will be the same.
1773 for (int i = 0; i < to_block->number_of_preds(); i++) {
1774 assert(from_block == to_block->pred_at(i), "all critical edges must be broken");
1775 }
1776 #endif
1777
1778 move_resolver.set_insert_position(to_block->lir(), 0);
1779 }
1780 }
1781
1782
1783 // insert necessary moves (spilling or reloading) at edges between blocks if interval has been split
1784 void LinearScan::resolve_data_flow() {
1785 TIME_LINEAR_SCAN(timer_resolve_data_flow);
1786
1787 int num_blocks = block_count();
1788 MoveResolver move_resolver(this);
1789 ResourceBitMap block_completed(num_blocks);
1790 ResourceBitMap already_resolved(num_blocks);
1791
1792 int i;
1793 for (i = 0; i < num_blocks; i++) {
1794 BlockBegin* block = block_at(i);
1795
1796 // check if block has only one predecessor and only one successor
1797 if (block->number_of_preds() == 1 && block->number_of_sux() == 1 && block->number_of_exception_handlers() == 0) {
1798 LIR_OpList* instructions = block->lir()->instructions_list();
1799 assert(instructions->at(0)->code() == lir_label, "block must start with label");
1800 assert(instructions->last()->code() == lir_branch, "block with successors must end with branch");
1801 assert(instructions->last()->as_OpBranch()->cond() == lir_cond_always, "block with successor must end with unconditional branch");
1802
1803 // check if block is empty (only label and branch)
1804 if (instructions->length() == 2) {
1805 BlockBegin* pred = block->pred_at(0);
1806 BlockBegin* sux = block->sux_at(0);
1807
1808 // prevent optimization of two consecutive blocks
1809 if (!block_completed.at(pred->linear_scan_number()) && !block_completed.at(sux->linear_scan_number())) {
1810 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()));
1811 block_completed.set_bit(block->linear_scan_number());
1812
1813 // directly resolve between pred and sux (without looking at the empty block between)
1814 resolve_collect_mappings(pred, sux, move_resolver);
1815 if (move_resolver.has_mappings()) {
1816 move_resolver.set_insert_position(block->lir(), 0);
1817 move_resolver.resolve_and_append_moves();
1818 }
1819 }
1820 }
1821 }
1822 }
1823
1824
1825 for (i = 0; i < num_blocks; i++) {
1826 if (!block_completed.at(i)) {
1827 BlockBegin* from_block = block_at(i);
1828 already_resolved.set_from(block_completed);
1829
1830 int num_sux = from_block->number_of_sux();
1831 for (int s = 0; s < num_sux; s++) {
1832 BlockBegin* to_block = from_block->sux_at(s);
1833
1834 // check for duplicate edges between the same blocks (can happen with switch blocks)
1835 if (!already_resolved.at(to_block->linear_scan_number())) {
1836 TRACE_LINEAR_SCAN(3, tty->print_cr("**** processing edge between B%d and B%d", from_block->block_id(), to_block->block_id()));
1837 already_resolved.set_bit(to_block->linear_scan_number());
1838
1839 // collect all intervals that have been split between from_block and to_block
1840 resolve_collect_mappings(from_block, to_block, move_resolver);
1841 if (move_resolver.has_mappings()) {
1842 resolve_find_insert_pos(from_block, to_block, move_resolver);
1843 move_resolver.resolve_and_append_moves();
1844 }
1845 }
1846 }
1847 }
1848 }
1849 }
1850
1851
1852 void LinearScan::resolve_exception_entry(BlockBegin* block, int reg_num, MoveResolver &move_resolver) {
1853 if (interval_at(reg_num) == NULL) {
1854 // if a phi function is never used, no interval is created -> ignore this
1855 return;
1856 }
1857
1858 Interval* interval = interval_at_block_begin(block, reg_num);
1859 int reg = interval->assigned_reg();
1860 int regHi = interval->assigned_regHi();
1861
1862 if ((reg < nof_regs && interval->always_in_memory()) ||
1863 (use_fpu_stack_allocation() && reg >= pd_first_fpu_reg && reg <= pd_last_fpu_reg)) {
1864 // the interval is split to get a short range that is located on the stack
1865 // in the following two cases:
1866 // * the interval started in memory (e.g. method parameter), but is currently in a register
1867 // this is an optimization for exception handling that reduces the number of moves that
1868 // are necessary for resolving the states when an exception uses this exception handler
1869 // * the interval would be on the fpu stack at the begin of the exception handler
1870 // this is not allowed because of the complicated fpu stack handling on Intel
1871
1872 // range that will be spilled to memory
1873 int from_op_id = block->first_lir_instruction_id();
1874 int to_op_id = from_op_id + 1; // short live range of length 1
1875 assert(interval->from() <= from_op_id && interval->to() >= to_op_id,
1876 "no split allowed between exception entry and first instruction");
1877
1878 if (interval->from() != from_op_id) {
1879 // the part before from_op_id is unchanged
1880 interval = interval->split(from_op_id);
1881 interval->assign_reg(reg, regHi);
1882 append_interval(interval);
1883 } else {
1884 _needs_full_resort = true;
1885 }
1886 assert(interval->from() == from_op_id, "must be true now");
1887
1888 Interval* spilled_part = interval;
1889 if (interval->to() != to_op_id) {
1890 // the part after to_op_id is unchanged
1891 spilled_part = interval->split_from_start(to_op_id);
1892 append_interval(spilled_part);
1893 move_resolver.add_mapping(spilled_part, interval);
1894 }
1895 assign_spill_slot(spilled_part);
1896
1897 assert(spilled_part->from() == from_op_id && spilled_part->to() == to_op_id, "just checking");
1898 }
1899 }
1900
1901 void LinearScan::resolve_exception_entry(BlockBegin* block, MoveResolver &move_resolver) {
1902 assert(block->is_set(BlockBegin::exception_entry_flag), "should not call otherwise");
1903 DEBUG_ONLY(move_resolver.check_empty());
1904
1905 // visit all registers where the live_in bit is set
1906 int size = live_set_size();
1907 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)) {
1908 resolve_exception_entry(block, r, move_resolver);
1909 }
1910
1911 // the live_in bits are not set for phi functions of the xhandler entry, so iterate them separately
1912 for_each_phi_fun(block, phi,
1913 if (!phi->is_illegal()) { resolve_exception_entry(block, phi->operand()->vreg_number(), move_resolver); }
1914 );
1915
1916 if (move_resolver.has_mappings()) {
1917 // insert moves after first instruction
1918 move_resolver.set_insert_position(block->lir(), 0);
1919 move_resolver.resolve_and_append_moves();
1920 }
1921 }
1922
1923
1924 void LinearScan::resolve_exception_edge(XHandler* handler, int throwing_op_id, int reg_num, Phi* phi, MoveResolver &move_resolver) {
1925 if (interval_at(reg_num) == NULL) {
1926 // if a phi function is never used, no interval is created -> ignore this
1927 return;
1928 }
1929
1930 // the computation of to_interval is equal to resolve_collect_mappings,
1931 // but from_interval is more complicated because of phi functions
1932 BlockBegin* to_block = handler->entry_block();
1933 Interval* to_interval = interval_at_block_begin(to_block, reg_num);
1934
1935 if (phi != NULL) {
1936 // phi function of the exception entry block
1937 // no moves are created for this phi function in the LIR_Generator, so the
1938 // interval at the throwing instruction must be searched using the operands
1939 // of the phi function
1940 Value from_value = phi->operand_at(handler->phi_operand());
1941
1942 // with phi functions it can happen that the same from_value is used in
1943 // multiple mappings, so notify move-resolver that this is allowed
1944 move_resolver.set_multiple_reads_allowed();
1945
1946 Constant* con = from_value->as_Constant();
1947 if (con != NULL && !con->is_pinned()) {
1948 // unpinned constants may have no register, so add mapping from constant to interval
1949 move_resolver.add_mapping(LIR_OprFact::value_type(con->type()), to_interval);
1950 } else {
1951 // search split child at the throwing op_id
1952 Interval* from_interval = interval_at_op_id(from_value->operand()->vreg_number(), throwing_op_id);
1953 move_resolver.add_mapping(from_interval, to_interval);
1954 }
1955
1956 } else {
1957 // no phi function, so use reg_num also for from_interval
1958 // search split child at the throwing op_id
1959 Interval* from_interval = interval_at_op_id(reg_num, throwing_op_id);
1960 if (from_interval != to_interval) {
1961 // optimization to reduce number of moves: when to_interval is on stack and
1962 // the stack slot is known to be always correct, then no move is necessary
1963 if (!from_interval->always_in_memory() || from_interval->canonical_spill_slot() != to_interval->assigned_reg()) {
1964 move_resolver.add_mapping(from_interval, to_interval);
1965 }
1966 }
1967 }
1968 }
1969
1970 void LinearScan::resolve_exception_edge(XHandler* handler, int throwing_op_id, MoveResolver &move_resolver) {
1971 TRACE_LINEAR_SCAN(4, tty->print_cr("resolving exception handler B%d: throwing_op_id=%d", handler->entry_block()->block_id(), throwing_op_id));
1972
1973 DEBUG_ONLY(move_resolver.check_empty());
1974 assert(handler->lir_op_id() == -1, "already processed this xhandler");
1975 DEBUG_ONLY(handler->set_lir_op_id(throwing_op_id));
1976 assert(handler->entry_code() == NULL, "code already present");
1977
1978 // visit all registers where the live_in bit is set
1979 BlockBegin* block = handler->entry_block();
1980 int size = live_set_size();
1981 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)) {
1982 resolve_exception_edge(handler, throwing_op_id, r, NULL, move_resolver);
1983 }
1984
1985 // the live_in bits are not set for phi functions of the xhandler entry, so iterate them separately
1986 for_each_phi_fun(block, phi,
1987 if (!phi->is_illegal()) { resolve_exception_edge(handler, throwing_op_id, phi->operand()->vreg_number(), phi, move_resolver); }
1988 );
1989
1990 if (move_resolver.has_mappings()) {
1991 LIR_List* entry_code = new LIR_List(compilation());
1992 move_resolver.set_insert_position(entry_code, 0);
1993 move_resolver.resolve_and_append_moves();
1994
1995 entry_code->jump(handler->entry_block());
1996 handler->set_entry_code(entry_code);
1997 }
1998 }
1999
2000
2001 void LinearScan::resolve_exception_handlers() {
2002 MoveResolver move_resolver(this);
2003 LIR_OpVisitState visitor;
2004 int num_blocks = block_count();
2005
2006 int i;
2007 for (i = 0; i < num_blocks; i++) {
2008 BlockBegin* block = block_at(i);
2009 if (block->is_set(BlockBegin::exception_entry_flag)) {
2010 resolve_exception_entry(block, move_resolver);
2011 }
2012 }
2013
2014 for (i = 0; i < num_blocks; i++) {
2015 BlockBegin* block = block_at(i);
2016 LIR_List* ops = block->lir();
2017 int num_ops = ops->length();
2018
2019 // iterate all instructions of the block. skip the first because it is always a label
2020 assert(visitor.no_operands(ops->at(0)), "first operation must always be a label");
2021 for (int j = 1; j < num_ops; j++) {
2022 LIR_Op* op = ops->at(j);
2023 int op_id = op->id();
2024
2025 if (op_id != -1 && has_info(op_id)) {
2026 // visit operation to collect all operands
2027 visitor.visit(op);
2028 assert(visitor.info_count() > 0, "should not visit otherwise");
2029
2030 XHandlers* xhandlers = visitor.all_xhandler();
2031 int n = xhandlers->length();
2032 for (int k = 0; k < n; k++) {
2033 resolve_exception_edge(xhandlers->handler_at(k), op_id, move_resolver);
2034 }
2035
2036 #ifdef ASSERT
2037 } else {
2038 visitor.visit(op);
2039 assert(visitor.all_xhandler()->length() == 0, "missed exception handler");
2040 #endif
2041 }
2042 }
2043 }
2044 }
2045
2046
2047 // ********** Phase 7: assign register numbers back to LIR
2048 // (includes computation of debug information and oop maps)
2049
2050 VMReg LinearScan::vm_reg_for_interval(Interval* interval) {
2051 VMReg reg = interval->cached_vm_reg();
2052 if (!reg->is_valid() ) {
2053 reg = vm_reg_for_operand(operand_for_interval(interval));
2054 interval->set_cached_vm_reg(reg);
2055 }
2056 assert(reg == vm_reg_for_operand(operand_for_interval(interval)), "wrong cached value");
2057 return reg;
2058 }
2059
2060 VMReg LinearScan::vm_reg_for_operand(LIR_Opr opr) {
2061 assert(opr->is_oop(), "currently only implemented for oop operands");
2062 return frame_map()->regname(opr);
2063 }
2064
2065
2066 LIR_Opr LinearScan::operand_for_interval(Interval* interval) {
2067 LIR_Opr opr = interval->cached_opr();
2068 if (opr->is_illegal()) {
2069 opr = calc_operand_for_interval(interval);
2070 interval->set_cached_opr(opr);
2071 }
2072
2073 assert(opr == calc_operand_for_interval(interval), "wrong cached value");
2074 return opr;
2075 }
2076
2077 LIR_Opr LinearScan::calc_operand_for_interval(const Interval* interval) {
2078 int assigned_reg = interval->assigned_reg();
2079 BasicType type = interval->type();
2080
2081 if (assigned_reg >= nof_regs) {
2082 // stack slot
2083 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2084 return LIR_OprFact::stack(assigned_reg - nof_regs, type);
2085
2086 } else {
2087 // register
2088 switch (type) {
2089 case T_OBJECT: {
2090 assert(assigned_reg >= pd_first_cpu_reg && assigned_reg <= pd_last_cpu_reg, "no cpu register");
2091 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2092 return LIR_OprFact::single_cpu_oop(assigned_reg);
2093 }
2094
2095 case T_ADDRESS: {
2096 assert(assigned_reg >= pd_first_cpu_reg && assigned_reg <= pd_last_cpu_reg, "no cpu register");
2097 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2098 return LIR_OprFact::single_cpu_address(assigned_reg);
2099 }
2100
2101 case T_METADATA: {
2102 assert(assigned_reg >= pd_first_cpu_reg && assigned_reg <= pd_last_cpu_reg, "no cpu register");
2103 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2104 return LIR_OprFact::single_cpu_metadata(assigned_reg);
2105 }
2106
2107 #ifdef __SOFTFP__
2108 case T_FLOAT: // fall through
2109 #endif // __SOFTFP__
2110 case T_INT: {
2111 assert(assigned_reg >= pd_first_cpu_reg && assigned_reg <= pd_last_cpu_reg, "no cpu register");
2112 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2113 return LIR_OprFact::single_cpu(assigned_reg);
2114 }
2115
2116 #ifdef __SOFTFP__
2117 case T_DOUBLE: // fall through
2118 #endif // __SOFTFP__
2119 case T_LONG: {
2120 int assigned_regHi = interval->assigned_regHi();
2121 assert(assigned_reg >= pd_first_cpu_reg && assigned_reg <= pd_last_cpu_reg, "no cpu register");
2122 assert(num_physical_regs(T_LONG) == 1 ||
2123 (assigned_regHi >= pd_first_cpu_reg && assigned_regHi <= pd_last_cpu_reg), "no cpu register");
2124
2125 assert(assigned_reg != assigned_regHi, "invalid allocation");
2126 assert(num_physical_regs(T_LONG) == 1 || assigned_reg < assigned_regHi,
2127 "register numbers must be sorted (ensure that e.g. a move from eax,ebx to ebx,eax can not occur)");
2128 assert((assigned_regHi != any_reg) ^ (num_physical_regs(T_LONG) == 1), "must be match");
2129 if (requires_adjacent_regs(T_LONG)) {
2130 assert(assigned_reg % 2 == 0 && assigned_reg + 1 == assigned_regHi, "must be sequential and even");
2131 }
2132
2133 #ifdef _LP64
2134 return LIR_OprFact::double_cpu(assigned_reg, assigned_reg);
2135 #else
2136 #if defined(SPARC) || defined(PPC32)
2137 return LIR_OprFact::double_cpu(assigned_regHi, assigned_reg);
2138 #else
2139 return LIR_OprFact::double_cpu(assigned_reg, assigned_regHi);
2140 #endif // SPARC
2141 #endif // LP64
2142 }
2143
2144 #ifndef __SOFTFP__
2145 case T_FLOAT: {
2146 #ifdef X86
2147 if (UseSSE >= 1) {
2148 int last_xmm_reg = pd_last_xmm_reg;
2149 #ifdef _LP64
2150 if (UseAVX < 3) {
2151 last_xmm_reg = pd_first_xmm_reg + (pd_nof_xmm_regs_frame_map / 2) - 1;
2152 }
2153 #endif
2154 assert(assigned_reg >= pd_first_xmm_reg && assigned_reg <= last_xmm_reg, "no xmm register");
2155 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2156 return LIR_OprFact::single_xmm(assigned_reg - pd_first_xmm_reg);
2157 }
2158 #endif
2159
2160 assert(assigned_reg >= pd_first_fpu_reg && assigned_reg <= pd_last_fpu_reg, "no fpu register");
2161 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2162 return LIR_OprFact::single_fpu(assigned_reg - pd_first_fpu_reg);
2163 }
2164
2165 case T_DOUBLE: {
2166 #ifdef X86
2167 if (UseSSE >= 2) {
2168 int last_xmm_reg = pd_last_xmm_reg;
2169 #ifdef _LP64
2170 if (UseAVX < 3) {
2171 last_xmm_reg = pd_first_xmm_reg + (pd_nof_xmm_regs_frame_map / 2) - 1;
2172 }
2173 #endif
2174 assert(assigned_reg >= pd_first_xmm_reg && assigned_reg <= last_xmm_reg, "no xmm register");
2175 assert(interval->assigned_regHi() == any_reg, "must not have hi register (double xmm values are stored in one register)");
2176 return LIR_OprFact::double_xmm(assigned_reg - pd_first_xmm_reg);
2177 }
2178 #endif
2179
2180 #ifdef SPARC
2181 assert(assigned_reg >= pd_first_fpu_reg && assigned_reg <= pd_last_fpu_reg, "no fpu register");
2182 assert(interval->assigned_regHi() >= pd_first_fpu_reg && interval->assigned_regHi() <= pd_last_fpu_reg, "no fpu register");
2183 assert(assigned_reg % 2 == 0 && assigned_reg + 1 == interval->assigned_regHi(), "must be sequential and even");
2184 LIR_Opr result = LIR_OprFact::double_fpu(interval->assigned_regHi() - pd_first_fpu_reg, assigned_reg - pd_first_fpu_reg);
2185 #elif defined(ARM32)
2186 assert(assigned_reg >= pd_first_fpu_reg && assigned_reg <= pd_last_fpu_reg, "no fpu register");
2187 assert(interval->assigned_regHi() >= pd_first_fpu_reg && interval->assigned_regHi() <= pd_last_fpu_reg, "no fpu register");
2188 assert(assigned_reg % 2 == 0 && assigned_reg + 1 == interval->assigned_regHi(), "must be sequential and even");
2189 LIR_Opr result = LIR_OprFact::double_fpu(assigned_reg - pd_first_fpu_reg, interval->assigned_regHi() - pd_first_fpu_reg);
2190 #else
2191 assert(assigned_reg >= pd_first_fpu_reg && assigned_reg <= pd_last_fpu_reg, "no fpu register");
2192 assert(interval->assigned_regHi() == any_reg, "must not have hi register (double fpu values are stored in one register on Intel)");
2193 LIR_Opr result = LIR_OprFact::double_fpu(assigned_reg - pd_first_fpu_reg);
2194 #endif
2195 return result;
2196 }
2197 #endif // __SOFTFP__
2198
2199 default: {
2200 ShouldNotReachHere();
2201 return LIR_OprFact::illegalOpr;
2202 }
2203 }
2204 }
2205 }
2206
2207 LIR_Opr LinearScan::canonical_spill_opr(Interval* interval) {
2208 assert(interval->canonical_spill_slot() >= nof_regs, "canonical spill slot not set");
2209 return LIR_OprFact::stack(interval->canonical_spill_slot() - nof_regs, interval->type());
2210 }
2211
2212 LIR_Opr LinearScan::color_lir_opr(LIR_Opr opr, int op_id, LIR_OpVisitState::OprMode mode) {
2213 assert(opr->is_virtual(), "should not call this otherwise");
2214
2215 Interval* interval = interval_at(opr->vreg_number());
2216 assert(interval != NULL, "interval must exist");
2217
2218 if (op_id != -1) {
2219 #ifdef ASSERT
2220 BlockBegin* block = block_of_op_with_id(op_id);
2221 if (block->number_of_sux() <= 1 && op_id == block->last_lir_instruction_id()) {
2222 // check if spill moves could have been appended at the end of this block, but
2223 // before the branch instruction. So the split child information for this branch would
2224 // be incorrect.
2225 LIR_OpBranch* branch = block->lir()->instructions_list()->last()->as_OpBranch();
2226 if (branch != NULL) {
2227 if (block->live_out().at(opr->vreg_number())) {
2228 assert(branch->cond() == lir_cond_always, "block does not end with an unconditional jump");
2229 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)");
2230 }
2231 }
2232 }
2233 #endif
2234
2235 // operands are not changed when an interval is split during allocation,
2236 // so search the right interval here
2237 interval = split_child_at_op_id(interval, op_id, mode);
2238 }
2239
2240 LIR_Opr res = operand_for_interval(interval);
2241
2242 #ifdef X86
2243 // new semantic for is_last_use: not only set on definite end of interval,
2244 // but also before hole
2245 // This may still miss some cases (e.g. for dead values), but it is not necessary that the
2246 // last use information is completely correct
2247 // information is only needed for fpu stack allocation
2248 if (res->is_fpu_register()) {
2249 if (opr->is_last_use() || op_id == interval->to() || (op_id != -1 && interval->has_hole_between(op_id, op_id + 1))) {
2250 assert(op_id == -1 || !is_block_begin(op_id), "holes at begin of block may also result from control flow");
2251 res = res->make_last_use();
2252 }
2253 }
2254 #endif
2255
2256 assert(!gen()->is_vreg_flag_set(opr->vreg_number(), LIRGenerator::callee_saved) || !FrameMap::is_caller_save_register(res), "bad allocation");
2257
2258 return res;
2259 }
2260
2261
2262 #ifdef ASSERT
2263 // some methods used to check correctness of debug information
2264
2265 void assert_no_register_values(GrowableArray<ScopeValue*>* values) {
2266 if (values == NULL) {
2267 return;
2268 }
2269
2270 for (int i = 0; i < values->length(); i++) {
2271 ScopeValue* value = values->at(i);
2272
2273 if (value->is_location()) {
2274 Location location = ((LocationValue*)value)->location();
2275 assert(location.where() == Location::on_stack, "value is in register");
2276 }
2277 }
2278 }
2279
2280 void assert_no_register_values(GrowableArray<MonitorValue*>* values) {
2281 if (values == NULL) {
2282 return;
2283 }
2284
2285 for (int i = 0; i < values->length(); i++) {
2286 MonitorValue* value = values->at(i);
2287
2288 if (value->owner()->is_location()) {
2289 Location location = ((LocationValue*)value->owner())->location();
2290 assert(location.where() == Location::on_stack, "owner is in register");
2291 }
2292 assert(value->basic_lock().where() == Location::on_stack, "basic_lock is in register");
2293 }
2294 }
2295
2296 void assert_equal(Location l1, Location l2) {
2297 assert(l1.where() == l2.where() && l1.type() == l2.type() && l1.offset() == l2.offset(), "");
2298 }
2299
2300 void assert_equal(ScopeValue* v1, ScopeValue* v2) {
2301 if (v1->is_location()) {
2302 assert(v2->is_location(), "");
2303 assert_equal(((LocationValue*)v1)->location(), ((LocationValue*)v2)->location());
2304 } else if (v1->is_constant_int()) {
2305 assert(v2->is_constant_int(), "");
2306 assert(((ConstantIntValue*)v1)->value() == ((ConstantIntValue*)v2)->value(), "");
2307 } else if (v1->is_constant_double()) {
2308 assert(v2->is_constant_double(), "");
2309 assert(((ConstantDoubleValue*)v1)->value() == ((ConstantDoubleValue*)v2)->value(), "");
2310 } else if (v1->is_constant_long()) {
2311 assert(v2->is_constant_long(), "");
2312 assert(((ConstantLongValue*)v1)->value() == ((ConstantLongValue*)v2)->value(), "");
2313 } else if (v1->is_constant_oop()) {
2314 assert(v2->is_constant_oop(), "");
2315 assert(((ConstantOopWriteValue*)v1)->value() == ((ConstantOopWriteValue*)v2)->value(), "");
2316 } else {
2317 ShouldNotReachHere();
2318 }
2319 }
2320
2321 void assert_equal(MonitorValue* m1, MonitorValue* m2) {
2322 assert_equal(m1->owner(), m2->owner());
2323 assert_equal(m1->basic_lock(), m2->basic_lock());
2324 }
2325
2326 void assert_equal(IRScopeDebugInfo* d1, IRScopeDebugInfo* d2) {
2327 assert(d1->scope() == d2->scope(), "not equal");
2328 assert(d1->bci() == d2->bci(), "not equal");
2329
2330 if (d1->locals() != NULL) {
2331 assert(d1->locals() != NULL && d2->locals() != NULL, "not equal");
2332 assert(d1->locals()->length() == d2->locals()->length(), "not equal");
2333 for (int i = 0; i < d1->locals()->length(); i++) {
2334 assert_equal(d1->locals()->at(i), d2->locals()->at(i));
2335 }
2336 } else {
2337 assert(d1->locals() == NULL && d2->locals() == NULL, "not equal");
2338 }
2339
2340 if (d1->expressions() != NULL) {
2341 assert(d1->expressions() != NULL && d2->expressions() != NULL, "not equal");
2342 assert(d1->expressions()->length() == d2->expressions()->length(), "not equal");
2343 for (int i = 0; i < d1->expressions()->length(); i++) {
2344 assert_equal(d1->expressions()->at(i), d2->expressions()->at(i));
2345 }
2346 } else {
2347 assert(d1->expressions() == NULL && d2->expressions() == NULL, "not equal");
2348 }
2349
2350 if (d1->monitors() != NULL) {
2351 assert(d1->monitors() != NULL && d2->monitors() != NULL, "not equal");
2352 assert(d1->monitors()->length() == d2->monitors()->length(), "not equal");
2353 for (int i = 0; i < d1->monitors()->length(); i++) {
2354 assert_equal(d1->monitors()->at(i), d2->monitors()->at(i));
2355 }
2356 } else {
2357 assert(d1->monitors() == NULL && d2->monitors() == NULL, "not equal");
2358 }
2359
2360 if (d1->caller() != NULL) {
2361 assert(d1->caller() != NULL && d2->caller() != NULL, "not equal");
2362 assert_equal(d1->caller(), d2->caller());
2363 } else {
2364 assert(d1->caller() == NULL && d2->caller() == NULL, "not equal");
2365 }
2366 }
2367
2368 void check_stack_depth(CodeEmitInfo* info, int stack_end) {
2369 if (info->stack()->bci() != SynchronizationEntryBCI && !info->scope()->method()->is_native()) {
2370 Bytecodes::Code code = info->scope()->method()->java_code_at_bci(info->stack()->bci());
2371 switch (code) {
2372 case Bytecodes::_ifnull : // fall through
2373 case Bytecodes::_ifnonnull : // fall through
2374 case Bytecodes::_ifeq : // fall through
2375 case Bytecodes::_ifne : // fall through
2376 case Bytecodes::_iflt : // fall through
2377 case Bytecodes::_ifge : // fall through
2378 case Bytecodes::_ifgt : // fall through
2379 case Bytecodes::_ifle : // fall through
2380 case Bytecodes::_if_icmpeq : // fall through
2381 case Bytecodes::_if_icmpne : // fall through
2382 case Bytecodes::_if_icmplt : // fall through
2383 case Bytecodes::_if_icmpge : // fall through
2384 case Bytecodes::_if_icmpgt : // fall through
2385 case Bytecodes::_if_icmple : // fall through
2386 case Bytecodes::_if_acmpeq : // fall through
2387 case Bytecodes::_if_acmpne :
2388 assert(stack_end >= -Bytecodes::depth(code), "must have non-empty expression stack at if bytecode");
2389 break;
2390 default:
2391 break;
2392 }
2393 }
2394 }
2395
2396 #endif // ASSERT
2397
2398
2399 IntervalWalker* LinearScan::init_compute_oop_maps() {
2400 // setup lists of potential oops for walking
2401 Interval* oop_intervals;
2402 Interval* non_oop_intervals;
2403
2404 create_unhandled_lists(&oop_intervals, &non_oop_intervals, is_oop_interval, NULL);
2405
2406 // intervals that have no oops inside need not to be processed
2407 // to ensure a walking until the last instruction id, add a dummy interval
2408 // with a high operation id
2409 non_oop_intervals = new Interval(any_reg);
2410 non_oop_intervals->add_range(max_jint - 2, max_jint - 1);
2411
2412 return new IntervalWalker(this, oop_intervals, non_oop_intervals);
2413 }
2414
2415
2416 OopMap* LinearScan::compute_oop_map(IntervalWalker* iw, LIR_Op* op, CodeEmitInfo* info, bool is_call_site) {
2417 TRACE_LINEAR_SCAN(3, tty->print_cr("creating oop map at op_id %d", op->id()));
2418
2419 // walk before the current operation -> intervals that start at
2420 // the operation (= output operands of the operation) are not
2421 // included in the oop map
2422 iw->walk_before(op->id());
2423
2424 int frame_size = frame_map()->framesize();
2425 int arg_count = frame_map()->oop_map_arg_count();
2426 OopMap* map = new OopMap(frame_size, arg_count);
2427
2428 // Iterate through active intervals
2429 for (Interval* interval = iw->active_first(fixedKind); interval != Interval::end(); interval = interval->next()) {
2430 int assigned_reg = interval->assigned_reg();
2431
2432 assert(interval->current_from() <= op->id() && op->id() <= interval->current_to(), "interval should not be active otherwise");
2433 assert(interval->assigned_regHi() == any_reg, "oop must be single word");
2434 assert(interval->reg_num() >= LIR_OprDesc::vreg_base, "fixed interval found");
2435
2436 // Check if this range covers the instruction. Intervals that
2437 // start or end at the current operation are not included in the
2438 // oop map, except in the case of patching moves. For patching
2439 // moves, any intervals which end at this instruction are included
2440 // in the oop map since we may safepoint while doing the patch
2441 // before we've consumed the inputs.
2442 if (op->is_patching() || op->id() < interval->current_to()) {
2443
2444 // caller-save registers must not be included into oop-maps at calls
2445 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");
2446
2447 VMReg name = vm_reg_for_interval(interval);
2448 set_oop(map, name);
2449
2450 // Spill optimization: when the stack value is guaranteed to be always correct,
2451 // then it must be added to the oop map even if the interval is currently in a register
2452 if (interval->always_in_memory() &&
2453 op->id() > interval->spill_definition_pos() &&
2454 interval->assigned_reg() != interval->canonical_spill_slot()) {
2455 assert(interval->spill_definition_pos() > 0, "position not set correctly");
2456 assert(interval->canonical_spill_slot() >= LinearScan::nof_regs, "no spill slot assigned");
2457 assert(interval->assigned_reg() < LinearScan::nof_regs, "interval is on stack, so stack slot is registered twice");
2458
2459 set_oop(map, frame_map()->slot_regname(interval->canonical_spill_slot() - LinearScan::nof_regs));
2460 }
2461 }
2462 }
2463
2464 // add oops from lock stack
2465 assert(info->stack() != NULL, "CodeEmitInfo must always have a stack");
2466 int locks_count = info->stack()->total_locks_size();
2467 for (int i = 0; i < locks_count; i++) {
2468 set_oop(map, frame_map()->monitor_object_regname(i));
2469 }
2470
2471 return map;
2472 }
2473
2474
2475 void LinearScan::compute_oop_map(IntervalWalker* iw, const LIR_OpVisitState &visitor, LIR_Op* op) {
2476 assert(visitor.info_count() > 0, "no oop map needed");
2477
2478 // compute oop_map only for first CodeEmitInfo
2479 // because it is (in most cases) equal for all other infos of the same operation
2480 CodeEmitInfo* first_info = visitor.info_at(0);
2481 OopMap* first_oop_map = compute_oop_map(iw, op, first_info, visitor.has_call());
2482
2483 for (int i = 0; i < visitor.info_count(); i++) {
2484 CodeEmitInfo* info = visitor.info_at(i);
2485 OopMap* oop_map = first_oop_map;
2486
2487 // compute worst case interpreter size in case of a deoptimization
2488 _compilation->update_interpreter_frame_size(info->interpreter_frame_size());
2489
2490 if (info->stack()->locks_size() != first_info->stack()->locks_size()) {
2491 // this info has a different number of locks then the precomputed oop map
2492 // (possible for lock and unlock instructions) -> compute oop map with
2493 // correct lock information
2494 oop_map = compute_oop_map(iw, op, info, visitor.has_call());
2495 }
2496
2497 if (info->_oop_map == NULL) {
2498 info->_oop_map = oop_map;
2499 } else {
2500 // a CodeEmitInfo can not be shared between different LIR-instructions
2501 // because interval splitting can occur anywhere between two instructions
2502 // and so the oop maps must be different
2503 // -> check if the already set oop_map is exactly the one calculated for this operation
2504 assert(info->_oop_map == oop_map, "same CodeEmitInfo used for multiple LIR instructions");
2505 }
2506 }
2507 }
2508
2509
2510 // frequently used constants
2511 // Allocate them with new so they are never destroyed (otherwise, a
2512 // forced exit could destroy these objects while they are still in
2513 // use).
2514 ConstantOopWriteValue* LinearScan::_oop_null_scope_value = new (ResourceObj::C_HEAP, mtCompiler) ConstantOopWriteValue(NULL);
2515 ConstantIntValue* LinearScan::_int_m1_scope_value = new (ResourceObj::C_HEAP, mtCompiler) ConstantIntValue(-1);
2516 ConstantIntValue* LinearScan::_int_0_scope_value = new (ResourceObj::C_HEAP, mtCompiler) ConstantIntValue((jint)0);
2517 ConstantIntValue* LinearScan::_int_1_scope_value = new (ResourceObj::C_HEAP, mtCompiler) ConstantIntValue(1);
2518 ConstantIntValue* LinearScan::_int_2_scope_value = new (ResourceObj::C_HEAP, mtCompiler) ConstantIntValue(2);
2519 LocationValue* _illegal_value = new (ResourceObj::C_HEAP, mtCompiler) LocationValue(Location());
2520
2521 void LinearScan::init_compute_debug_info() {
2522 // cache for frequently used scope values
2523 // (cpu registers and stack slots)
2524 int cache_size = (LinearScan::nof_cpu_regs + frame_map()->argcount() + max_spills()) * 2;
2525 _scope_value_cache = ScopeValueArray(cache_size, cache_size, NULL);
2526 }
2527
2528 MonitorValue* LinearScan::location_for_monitor_index(int monitor_index) {
2529 Location loc;
2530 if (!frame_map()->location_for_monitor_object(monitor_index, &loc)) {
2531 bailout("too large frame");
2532 }
2533 ScopeValue* object_scope_value = new LocationValue(loc);
2534
2535 if (!frame_map()->location_for_monitor_lock(monitor_index, &loc)) {
2536 bailout("too large frame");
2537 }
2538 return new MonitorValue(object_scope_value, loc);
2539 }
2540
2541 LocationValue* LinearScan::location_for_name(int name, Location::Type loc_type) {
2542 Location loc;
2543 if (!frame_map()->locations_for_slot(name, loc_type, &loc)) {
2544 bailout("too large frame");
2545 }
2546 return new LocationValue(loc);
2547 }
2548
2549
2550 int LinearScan::append_scope_value_for_constant(LIR_Opr opr, GrowableArray<ScopeValue*>* scope_values) {
2551 assert(opr->is_constant(), "should not be called otherwise");
2552
2553 LIR_Const* c = opr->as_constant_ptr();
2554 BasicType t = c->type();
2555 switch (t) {
2556 case T_OBJECT: {
2557 jobject value = c->as_jobject();
2558 if (value == NULL) {
2559 scope_values->append(_oop_null_scope_value);
2560 } else {
2561 scope_values->append(new ConstantOopWriteValue(c->as_jobject()));
2562 }
2563 return 1;
2564 }
2565
2566 case T_INT: // fall through
2567 case T_FLOAT: {
2568 int value = c->as_jint_bits();
2569 switch (value) {
2570 case -1: scope_values->append(_int_m1_scope_value); break;
2571 case 0: scope_values->append(_int_0_scope_value); break;
2572 case 1: scope_values->append(_int_1_scope_value); break;
2573 case 2: scope_values->append(_int_2_scope_value); break;
2574 default: scope_values->append(new ConstantIntValue(c->as_jint_bits())); break;
2575 }
2576 return 1;
2577 }
2578
2579 case T_LONG: // fall through
2580 case T_DOUBLE: {
2581 #ifdef _LP64
2582 scope_values->append(_int_0_scope_value);
2583 scope_values->append(new ConstantLongValue(c->as_jlong_bits()));
2584 #else
2585 if (hi_word_offset_in_bytes > lo_word_offset_in_bytes) {
2586 scope_values->append(new ConstantIntValue(c->as_jint_hi_bits()));
2587 scope_values->append(new ConstantIntValue(c->as_jint_lo_bits()));
2588 } else {
2589 scope_values->append(new ConstantIntValue(c->as_jint_lo_bits()));
2590 scope_values->append(new ConstantIntValue(c->as_jint_hi_bits()));
2591 }
2592 #endif
2593 return 2;
2594 }
2595
2596 case T_ADDRESS: {
2597 #ifdef _LP64
2598 scope_values->append(new ConstantLongValue(c->as_jint()));
2599 #else
2600 scope_values->append(new ConstantIntValue(c->as_jint()));
2601 #endif
2602 return 1;
2603 }
2604
2605 default:
2606 ShouldNotReachHere();
2607 return -1;
2608 }
2609 }
2610
2611 int LinearScan::append_scope_value_for_operand(LIR_Opr opr, GrowableArray<ScopeValue*>* scope_values) {
2612 if (opr->is_single_stack()) {
2613 int stack_idx = opr->single_stack_ix();
2614 bool is_oop = opr->is_oop_register();
2615 int cache_idx = (stack_idx + LinearScan::nof_cpu_regs) * 2 + (is_oop ? 1 : 0);
2616
2617 ScopeValue* sv = _scope_value_cache.at(cache_idx);
2618 if (sv == NULL) {
2619 Location::Type loc_type = is_oop ? Location::oop : Location::normal;
2620 sv = location_for_name(stack_idx, loc_type);
2621 _scope_value_cache.at_put(cache_idx, sv);
2622 }
2623
2624 // check if cached value is correct
2625 DEBUG_ONLY(assert_equal(sv, location_for_name(stack_idx, is_oop ? Location::oop : Location::normal)));
2626
2627 scope_values->append(sv);
2628 return 1;
2629
2630 } else if (opr->is_single_cpu()) {
2631 bool is_oop = opr->is_oop_register();
2632 int cache_idx = opr->cpu_regnr() * 2 + (is_oop ? 1 : 0);
2633 Location::Type int_loc_type = NOT_LP64(Location::normal) LP64_ONLY(Location::int_in_long);
2634
2635 ScopeValue* sv = _scope_value_cache.at(cache_idx);
2636 if (sv == NULL) {
2637 Location::Type loc_type = is_oop ? Location::oop : int_loc_type;
2638 VMReg rname = frame_map()->regname(opr);
2639 sv = new LocationValue(Location::new_reg_loc(loc_type, rname));
2640 _scope_value_cache.at_put(cache_idx, sv);
2641 }
2642
2643 // check if cached value is correct
2644 DEBUG_ONLY(assert_equal(sv, new LocationValue(Location::new_reg_loc(is_oop ? Location::oop : int_loc_type, frame_map()->regname(opr)))));
2645
2646 scope_values->append(sv);
2647 return 1;
2648
2649 #ifdef X86
2650 } else if (opr->is_single_xmm()) {
2651 VMReg rname = opr->as_xmm_float_reg()->as_VMReg();
2652 LocationValue* sv = new LocationValue(Location::new_reg_loc(Location::normal, rname));
2653
2654 scope_values->append(sv);
2655 return 1;
2656 #endif
2657
2658 } else if (opr->is_single_fpu()) {
2659 #ifdef IA32
2660 // the exact location of fpu stack values is only known
2661 // during fpu stack allocation, so the stack allocator object
2662 // must be present
2663 assert(use_fpu_stack_allocation(), "should not have float stack values without fpu stack allocation (all floats must be SSE2)");
2664 assert(_fpu_stack_allocator != NULL, "must be present");
2665 opr = _fpu_stack_allocator->to_fpu_stack(opr);
2666 #elif defined(AMD64)
2667 assert(false, "FPU not used on x86-64");
2668 #endif
2669
2670 Location::Type loc_type = float_saved_as_double ? Location::float_in_dbl : Location::normal;
2671 VMReg rname = frame_map()->fpu_regname(opr->fpu_regnr());
2672 #ifndef __SOFTFP__
2673 #ifndef VM_LITTLE_ENDIAN
2674 // On S390 a (single precision) float value occupies only the high
2675 // word of the full double register. So when the double register is
2676 // stored to memory (e.g. by the RegisterSaver), then the float value
2677 // is found at offset 0. I.e. the code below is not needed on S390.
2678 #ifndef S390
2679 if (! float_saved_as_double) {
2680 // On big endian system, we may have an issue if float registers use only
2681 // the low half of the (same) double registers.
2682 // Both the float and the double could have the same regnr but would correspond
2683 // to two different addresses once saved.
2684
2685 // get next safely (no assertion checks)
2686 VMReg next = VMRegImpl::as_VMReg(1+rname->value());
2687 if (next->is_reg() &&
2688 (next->as_FloatRegister() == rname->as_FloatRegister())) {
2689 // the back-end does use the same numbering for the double and the float
2690 rname = next; // VMReg for the low bits, e.g. the real VMReg for the float
2691 }
2692 }
2693 #endif // !S390
2694 #endif
2695 #endif
2696 LocationValue* sv = new LocationValue(Location::new_reg_loc(loc_type, rname));
2697
2698 scope_values->append(sv);
2699 return 1;
2700
2701 } else {
2702 // double-size operands
2703
2704 ScopeValue* first;
2705 ScopeValue* second;
2706
2707 if (opr->is_double_stack()) {
2708 #ifdef _LP64
2709 Location loc1;
2710 Location::Type loc_type = opr->type() == T_LONG ? Location::lng : Location::dbl;
2711 if (!frame_map()->locations_for_slot(opr->double_stack_ix(), loc_type, &loc1, NULL)) {
2712 bailout("too large frame");
2713 }
2714 // Does this reverse on x86 vs. sparc?
2715 first = new LocationValue(loc1);
2716 second = _int_0_scope_value;
2717 #else
2718 Location loc1, loc2;
2719 if (!frame_map()->locations_for_slot(opr->double_stack_ix(), Location::normal, &loc1, &loc2)) {
2720 bailout("too large frame");
2721 }
2722 first = new LocationValue(loc1);
2723 second = new LocationValue(loc2);
2724 #endif // _LP64
2725
2726 } else if (opr->is_double_cpu()) {
2727 #ifdef _LP64
2728 VMReg rname_first = opr->as_register_lo()->as_VMReg();
2729 first = new LocationValue(Location::new_reg_loc(Location::lng, rname_first));
2730 second = _int_0_scope_value;
2731 #else
2732 VMReg rname_first = opr->as_register_lo()->as_VMReg();
2733 VMReg rname_second = opr->as_register_hi()->as_VMReg();
2734
2735 if (hi_word_offset_in_bytes < lo_word_offset_in_bytes) {
2736 // lo/hi and swapped relative to first and second, so swap them
2737 VMReg tmp = rname_first;
2738 rname_first = rname_second;
2739 rname_second = tmp;
2740 }
2741
2742 first = new LocationValue(Location::new_reg_loc(Location::normal, rname_first));
2743 second = new LocationValue(Location::new_reg_loc(Location::normal, rname_second));
2744 #endif //_LP64
2745
2746
2747 #ifdef X86
2748 } else if (opr->is_double_xmm()) {
2749 assert(opr->fpu_regnrLo() == opr->fpu_regnrHi(), "assumed in calculation");
2750 VMReg rname_first = opr->as_xmm_double_reg()->as_VMReg();
2751 # ifdef _LP64
2752 first = new LocationValue(Location::new_reg_loc(Location::dbl, rname_first));
2753 second = _int_0_scope_value;
2754 # else
2755 first = new LocationValue(Location::new_reg_loc(Location::normal, rname_first));
2756 // %%% This is probably a waste but we'll keep things as they were for now
2757 if (true) {
2758 VMReg rname_second = rname_first->next();
2759 second = new LocationValue(Location::new_reg_loc(Location::normal, rname_second));
2760 }
2761 # endif
2762 #endif
2763
2764 } else if (opr->is_double_fpu()) {
2765 // On SPARC, fpu_regnrLo/fpu_regnrHi represents the two halves of
2766 // the double as float registers in the native ordering. On X86,
2767 // fpu_regnrLo is a FPU stack slot whose VMReg represents
2768 // the low-order word of the double and fpu_regnrLo + 1 is the
2769 // name for the other half. *first and *second must represent the
2770 // least and most significant words, respectively.
2771
2772 #ifdef IA32
2773 // the exact location of fpu stack values is only known
2774 // during fpu stack allocation, so the stack allocator object
2775 // must be present
2776 assert(use_fpu_stack_allocation(), "should not have float stack values without fpu stack allocation (all floats must be SSE2)");
2777 assert(_fpu_stack_allocator != NULL, "must be present");
2778 opr = _fpu_stack_allocator->to_fpu_stack(opr);
2779
2780 assert(opr->fpu_regnrLo() == opr->fpu_regnrHi(), "assumed in calculation (only fpu_regnrLo is used)");
2781 #endif
2782 #ifdef IA64
2783 assert(false, "FPU not used on x86-64");
2784 #endif
2785 #ifdef SPARC
2786 assert(opr->fpu_regnrLo() == opr->fpu_regnrHi() + 1, "assumed in calculation (only fpu_regnrHi is used)");
2787 #endif
2788 #ifdef ARM32
2789 assert(opr->fpu_regnrHi() == opr->fpu_regnrLo() + 1, "assumed in calculation (only fpu_regnrLo is used)");
2790 #endif
2791 #ifdef PPC32
2792 assert(opr->fpu_regnrLo() == opr->fpu_regnrHi(), "assumed in calculation (only fpu_regnrHi is used)");
2793 #endif
2794
2795 #ifdef VM_LITTLE_ENDIAN
2796 VMReg rname_first = frame_map()->fpu_regname(opr->fpu_regnrLo());
2797 #else
2798 VMReg rname_first = frame_map()->fpu_regname(opr->fpu_regnrHi());
2799 #endif
2800
2801 #ifdef _LP64
2802 first = new LocationValue(Location::new_reg_loc(Location::dbl, rname_first));
2803 second = _int_0_scope_value;
2804 #else
2805 first = new LocationValue(Location::new_reg_loc(Location::normal, rname_first));
2806 // %%% This is probably a waste but we'll keep things as they were for now
2807 if (true) {
2808 VMReg rname_second = rname_first->next();
2809 second = new LocationValue(Location::new_reg_loc(Location::normal, rname_second));
2810 }
2811 #endif
2812
2813 } else {
2814 ShouldNotReachHere();
2815 first = NULL;
2816 second = NULL;
2817 }
2818
2819 assert(first != NULL && second != NULL, "must be set");
2820 // The convention the interpreter uses is that the second local
2821 // holds the first raw word of the native double representation.
2822 // This is actually reasonable, since locals and stack arrays
2823 // grow downwards in all implementations.
2824 // (If, on some machine, the interpreter's Java locals or stack
2825 // were to grow upwards, the embedded doubles would be word-swapped.)
2826 scope_values->append(second);
2827 scope_values->append(first);
2828 return 2;
2829 }
2830 }
2831
2832
2833 int LinearScan::append_scope_value(int op_id, Value value, GrowableArray<ScopeValue*>* scope_values) {
2834 if (value != NULL) {
2835 LIR_Opr opr = value->operand();
2836 Constant* con = value->as_Constant();
2837
2838 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)");
2839 assert(con != NULL || opr->is_virtual(), "asumption: non-Constant instructions have only virtual operands");
2840
2841 if (con != NULL && !con->is_pinned() && !opr->is_constant()) {
2842 // Unpinned constants may have a virtual operand for a part of the lifetime
2843 // or may be illegal when it was optimized away,
2844 // so always use a constant operand
2845 opr = LIR_OprFact::value_type(con->type());
2846 }
2847 assert(opr->is_virtual() || opr->is_constant(), "other cases not allowed here");
2848
2849 if (opr->is_virtual()) {
2850 LIR_OpVisitState::OprMode mode = LIR_OpVisitState::inputMode;
2851
2852 BlockBegin* block = block_of_op_with_id(op_id);
2853 if (block->number_of_sux() == 1 && op_id == block->last_lir_instruction_id()) {
2854 // generating debug information for the last instruction of a block.
2855 // if this instruction is a branch, spill moves are inserted before this branch
2856 // and so the wrong operand would be returned (spill moves at block boundaries are not
2857 // considered in the live ranges of intervals)
2858 // Solution: use the first op_id of the branch target block instead.
2859 if (block->lir()->instructions_list()->last()->as_OpBranch() != NULL) {
2860 if (block->live_out().at(opr->vreg_number())) {
2861 op_id = block->sux_at(0)->first_lir_instruction_id();
2862 mode = LIR_OpVisitState::outputMode;
2863 }
2864 }
2865 }
2866
2867 // Get current location of operand
2868 // The operand must be live because debug information is considered when building the intervals
2869 // if the interval is not live, color_lir_opr will cause an assertion failure
2870 opr = color_lir_opr(opr, op_id, mode);
2871 assert(!has_call(op_id) || opr->is_stack() || !is_caller_save(reg_num(opr)), "can not have caller-save register operands at calls");
2872
2873 // Append to ScopeValue array
2874 return append_scope_value_for_operand(opr, scope_values);
2875
2876 } else {
2877 assert(value->as_Constant() != NULL, "all other instructions have only virtual operands");
2878 assert(opr->is_constant(), "operand must be constant");
2879
2880 return append_scope_value_for_constant(opr, scope_values);
2881 }
2882 } else {
2883 // append a dummy value because real value not needed
2884 scope_values->append(_illegal_value);
2885 return 1;
2886 }
2887 }
2888
2889
2890 IRScopeDebugInfo* LinearScan::compute_debug_info_for_scope(int op_id, IRScope* cur_scope, ValueStack* cur_state, ValueStack* innermost_state) {
2891 IRScopeDebugInfo* caller_debug_info = NULL;
2892
2893 ValueStack* caller_state = cur_state->caller_state();
2894 if (caller_state != NULL) {
2895 // process recursively to compute outermost scope first
2896 caller_debug_info = compute_debug_info_for_scope(op_id, cur_scope->caller(), caller_state, innermost_state);
2897 }
2898
2899 // initialize these to null.
2900 // If we don't need deopt info or there are no locals, expressions or monitors,
2901 // then these get recorded as no information and avoids the allocation of 0 length arrays.
2902 GrowableArray<ScopeValue*>* locals = NULL;
2903 GrowableArray<ScopeValue*>* expressions = NULL;
2904 GrowableArray<MonitorValue*>* monitors = NULL;
2905
2906 // describe local variable values
2907 int nof_locals = cur_state->locals_size();
2908 if (nof_locals > 0) {
2909 locals = new GrowableArray<ScopeValue*>(nof_locals);
2910
2911 int pos = 0;
2912 while (pos < nof_locals) {
2913 assert(pos < cur_state->locals_size(), "why not?");
2914
2915 Value local = cur_state->local_at(pos);
2916 pos += append_scope_value(op_id, local, locals);
2917
2918 assert(locals->length() == pos, "must match");
2919 }
2920 assert(locals->length() == cur_scope->method()->max_locals(), "wrong number of locals");
2921 assert(locals->length() == cur_state->locals_size(), "wrong number of locals");
2922 } else if (cur_scope->method()->max_locals() > 0) {
2923 assert(cur_state->kind() == ValueStack::EmptyExceptionState, "should be");
2924 nof_locals = cur_scope->method()->max_locals();
2925 locals = new GrowableArray<ScopeValue*>(nof_locals);
2926 for(int i = 0; i < nof_locals; i++) {
2927 locals->append(_illegal_value);
2928 }
2929 }
2930
2931 // describe expression stack
2932 int nof_stack = cur_state->stack_size();
2933 if (nof_stack > 0) {
2934 expressions = new GrowableArray<ScopeValue*>(nof_stack);
2935
2936 int pos = 0;
2937 while (pos < nof_stack) {
2938 Value expression = cur_state->stack_at_inc(pos);
2939 append_scope_value(op_id, expression, expressions);
2940
2941 assert(expressions->length() == pos, "must match");
2942 }
2943 assert(expressions->length() == cur_state->stack_size(), "wrong number of stack entries");
2944 }
2945
2946 // describe monitors
2947 int nof_locks = cur_state->locks_size();
2948 if (nof_locks > 0) {
2949 int lock_offset = cur_state->caller_state() != NULL ? cur_state->caller_state()->total_locks_size() : 0;
2950 monitors = new GrowableArray<MonitorValue*>(nof_locks);
2951 for (int i = 0; i < nof_locks; i++) {
2952 monitors->append(location_for_monitor_index(lock_offset + i));
2953 }
2954 }
2955
2956 return new IRScopeDebugInfo(cur_scope, cur_state->bci(), locals, expressions, monitors, caller_debug_info);
2957 }
2958
2959
2960 void LinearScan::compute_debug_info(CodeEmitInfo* info, int op_id) {
2961 TRACE_LINEAR_SCAN(3, tty->print_cr("creating debug information at op_id %d", op_id));
2962
2963 IRScope* innermost_scope = info->scope();
2964 ValueStack* innermost_state = info->stack();
2965
2966 assert(innermost_scope != NULL && innermost_state != NULL, "why is it missing?");
2967
2968 DEBUG_ONLY(check_stack_depth(info, innermost_state->stack_size()));
2969
2970 if (info->_scope_debug_info == NULL) {
2971 // compute debug information
2972 info->_scope_debug_info = compute_debug_info_for_scope(op_id, innermost_scope, innermost_state, innermost_state);
2973 } else {
2974 // debug information already set. Check that it is correct from the current point of view
2975 DEBUG_ONLY(assert_equal(info->_scope_debug_info, compute_debug_info_for_scope(op_id, innermost_scope, innermost_state, innermost_state)));
2976 }
2977 }
2978
2979
2980 void LinearScan::assign_reg_num(LIR_OpList* instructions, IntervalWalker* iw) {
2981 LIR_OpVisitState visitor;
2982 int num_inst = instructions->length();
2983 bool has_dead = false;
2984
2985 for (int j = 0; j < num_inst; j++) {
2986 LIR_Op* op = instructions->at(j);
2987 if (op == NULL) { // this can happen when spill-moves are removed in eliminate_spill_moves
2988 has_dead = true;
2989 continue;
2990 }
2991 int op_id = op->id();
2992
2993 // visit instruction to get list of operands
2994 visitor.visit(op);
2995
2996 // iterate all modes of the visitor and process all virtual operands
2997 for_each_visitor_mode(mode) {
2998 int n = visitor.opr_count(mode);
2999 for (int k = 0; k < n; k++) {
3000 LIR_Opr opr = visitor.opr_at(mode, k);
3001 if (opr->is_virtual_register()) {
3002 visitor.set_opr_at(mode, k, color_lir_opr(opr, op_id, mode));
3003 }
3004 }
3005 }
3006
3007 if (visitor.info_count() > 0) {
3008 // exception handling
3009 if (compilation()->has_exception_handlers()) {
3010 XHandlers* xhandlers = visitor.all_xhandler();
3011 int n = xhandlers->length();
3012 for (int k = 0; k < n; k++) {
3013 XHandler* handler = xhandlers->handler_at(k);
3014 if (handler->entry_code() != NULL) {
3015 assign_reg_num(handler->entry_code()->instructions_list(), NULL);
3016 }
3017 }
3018 } else {
3019 assert(visitor.all_xhandler()->length() == 0, "missed exception handler");
3020 }
3021
3022 // compute oop map
3023 assert(iw != NULL, "needed for compute_oop_map");
3024 compute_oop_map(iw, visitor, op);
3025
3026 // compute debug information
3027 if (!use_fpu_stack_allocation()) {
3028 // compute debug information if fpu stack allocation is not needed.
3029 // when fpu stack allocation is needed, the debug information can not
3030 // be computed here because the exact location of fpu operands is not known
3031 // -> debug information is created inside the fpu stack allocator
3032 int n = visitor.info_count();
3033 for (int k = 0; k < n; k++) {
3034 compute_debug_info(visitor.info_at(k), op_id);
3035 }
3036 }
3037 }
3038
3039 #ifdef ASSERT
3040 // make sure we haven't made the op invalid.
3041 op->verify();
3042 #endif
3043
3044 // remove useless moves
3045 if (op->code() == lir_move) {
3046 assert(op->as_Op1() != NULL, "move must be LIR_Op1");
3047 LIR_Op1* move = (LIR_Op1*)op;
3048 LIR_Opr src = move->in_opr();
3049 LIR_Opr dst = move->result_opr();
3050 if (dst == src ||
3051 (!dst->is_pointer() && !src->is_pointer() &&
3052 src->is_same_register(dst))) {
3053 instructions->at_put(j, NULL);
3054 has_dead = true;
3055 }
3056 }
3057 }
3058
3059 if (has_dead) {
3060 // iterate all instructions of the block and remove all null-values.
3061 int insert_point = 0;
3062 for (int j = 0; j < num_inst; j++) {
3063 LIR_Op* op = instructions->at(j);
3064 if (op != NULL) {
3065 if (insert_point != j) {
3066 instructions->at_put(insert_point, op);
3067 }
3068 insert_point++;
3069 }
3070 }
3071 instructions->trunc_to(insert_point);
3072 }
3073 }
3074
3075 void LinearScan::assign_reg_num() {
3076 TIME_LINEAR_SCAN(timer_assign_reg_num);
3077
3078 init_compute_debug_info();
3079 IntervalWalker* iw = init_compute_oop_maps();
3080
3081 int num_blocks = block_count();
3082 for (int i = 0; i < num_blocks; i++) {
3083 BlockBegin* block = block_at(i);
3084 assign_reg_num(block->lir()->instructions_list(), iw);
3085 }
3086 }
3087
3088
3089 void LinearScan::do_linear_scan() {
3090 NOT_PRODUCT(_total_timer.begin_method());
3091
3092 number_instructions();
3093
3094 NOT_PRODUCT(print_lir(1, "Before Register Allocation"));
3095
3096 compute_local_live_sets();
3097 compute_global_live_sets();
3098 CHECK_BAILOUT();
3099
3100 build_intervals();
3101 CHECK_BAILOUT();
3102 sort_intervals_before_allocation();
3103
3104 NOT_PRODUCT(print_intervals("Before Register Allocation"));
3105 NOT_PRODUCT(LinearScanStatistic::compute(this, _stat_before_alloc));
3106
3107 allocate_registers();
3108 CHECK_BAILOUT();
3109
3110 resolve_data_flow();
3111 if (compilation()->has_exception_handlers()) {
3112 resolve_exception_handlers();
3113 }
3114 // fill in number of spill slots into frame_map
3115 propagate_spill_slots();
3116 CHECK_BAILOUT();
3117
3118 NOT_PRODUCT(print_intervals("After Register Allocation"));
3119 NOT_PRODUCT(print_lir(2, "LIR after register allocation:"));
3120
3121 sort_intervals_after_allocation();
3122
3123 DEBUG_ONLY(verify());
3124
3125 eliminate_spill_moves();
3126 assign_reg_num();
3127 CHECK_BAILOUT();
3128
3129 NOT_PRODUCT(print_lir(2, "LIR after assignment of register numbers:"));
3130 NOT_PRODUCT(LinearScanStatistic::compute(this, _stat_after_asign));
3131
3132 { TIME_LINEAR_SCAN(timer_allocate_fpu_stack);
3133
3134 if (use_fpu_stack_allocation()) {
3135 allocate_fpu_stack(); // Only has effect on Intel
3136 NOT_PRODUCT(print_lir(2, "LIR after FPU stack allocation:"));
3137 }
3138 }
3139
3140 { TIME_LINEAR_SCAN(timer_optimize_lir);
3141
3142 EdgeMoveOptimizer::optimize(ir()->code());
3143 ControlFlowOptimizer::optimize(ir()->code());
3144 // check that cfg is still correct after optimizations
3145 ir()->verify();
3146 }
3147
3148 NOT_PRODUCT(print_lir(1, "Before Code Generation", false));
3149 NOT_PRODUCT(LinearScanStatistic::compute(this, _stat_final));
3150 NOT_PRODUCT(_total_timer.end_method(this));
3151 }
3152
3153
3154 // ********** Printing functions
3155
3156 #ifndef PRODUCT
3157
3158 void LinearScan::print_timers(double total) {
3159 _total_timer.print(total);
3160 }
3161
3162 void LinearScan::print_statistics() {
3163 _stat_before_alloc.print("before allocation");
3164 _stat_after_asign.print("after assignment of register");
3165 _stat_final.print("after optimization");
3166 }
3167
3168 void LinearScan::print_bitmap(BitMap& b) {
3169 for (unsigned int i = 0; i < b.size(); i++) {
3170 if (b.at(i)) tty->print("%d ", i);
3171 }
3172 tty->cr();
3173 }
3174
3175 void LinearScan::print_intervals(const char* label) {
3176 if (TraceLinearScanLevel >= 1) {
3177 int i;
3178 tty->cr();
3179 tty->print_cr("%s", label);
3180
3181 for (i = 0; i < interval_count(); i++) {
3182 Interval* interval = interval_at(i);
3183 if (interval != NULL) {
3184 interval->print();
3185 }
3186 }
3187
3188 tty->cr();
3189 tty->print_cr("--- Basic Blocks ---");
3190 for (i = 0; i < block_count(); i++) {
3191 BlockBegin* block = block_at(i);
3192 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());
3193 }
3194 tty->cr();
3195 tty->cr();
3196 }
3197
3198 if (PrintCFGToFile) {
3199 CFGPrinter::print_intervals(&_intervals, label);
3200 }
3201 }
3202
3203 void LinearScan::print_lir(int level, const char* label, bool hir_valid) {
3204 if (TraceLinearScanLevel >= level) {
3205 tty->cr();
3206 tty->print_cr("%s", label);
3207 print_LIR(ir()->linear_scan_order());
3208 tty->cr();
3209 }
3210
3211 if (level == 1 && PrintCFGToFile) {
3212 CFGPrinter::print_cfg(ir()->linear_scan_order(), label, hir_valid, true);
3213 }
3214 }
3215
3216 #endif //PRODUCT
3217
3218
3219 // ********** verification functions for allocation
3220 // (check that all intervals have a correct register and that no registers are overwritten)
3221 #ifdef ASSERT
3222
3223 void LinearScan::verify() {
3224 TRACE_LINEAR_SCAN(2, tty->print_cr("********* verifying intervals ******************************************"));
3225 verify_intervals();
3226
3227 TRACE_LINEAR_SCAN(2, tty->print_cr("********* verifying that no oops are in fixed intervals ****************"));
3228 verify_no_oops_in_fixed_intervals();
3229
3230 TRACE_LINEAR_SCAN(2, tty->print_cr("********* verifying that unpinned constants are not alive across block boundaries"));
3231 verify_constants();
3232
3233 TRACE_LINEAR_SCAN(2, tty->print_cr("********* verifying register allocation ********************************"));
3234 verify_registers();
3235
3236 TRACE_LINEAR_SCAN(2, tty->print_cr("********* no errors found **********************************************"));
3237 }
3238
3239 void LinearScan::verify_intervals() {
3240 int len = interval_count();
3241 bool has_error = false;
3242
3243 for (int i = 0; i < len; i++) {
3244 Interval* i1 = interval_at(i);
3245 if (i1 == NULL) continue;
3246
3247 i1->check_split_children();
3248
3249 if (i1->reg_num() != i) {
3250 tty->print_cr("Interval %d is on position %d in list", i1->reg_num(), i); i1->print(); tty->cr();
3251 has_error = true;
3252 }
3253
3254 if (i1->reg_num() >= LIR_OprDesc::vreg_base && i1->type() == T_ILLEGAL) {
3255 tty->print_cr("Interval %d has no type assigned", i1->reg_num()); i1->print(); tty->cr();
3256 has_error = true;
3257 }
3258
3259 if (i1->assigned_reg() == any_reg) {
3260 tty->print_cr("Interval %d has no register assigned", i1->reg_num()); i1->print(); tty->cr();
3261 has_error = true;
3262 }
3263
3264 if (i1->assigned_reg() == i1->assigned_regHi()) {
3265 tty->print_cr("Interval %d: low and high register equal", i1->reg_num()); i1->print(); tty->cr();
3266 has_error = true;
3267 }
3268
3269 if (!is_processed_reg_num(i1->assigned_reg())) {
3270 tty->print_cr("Can not have an Interval for an ignored register"); i1->print(); tty->cr();
3271 has_error = true;
3272 }
3273
3274 // special intervals that are created in MoveResolver
3275 // -> ignore them because the range information has no meaning there
3276 if (i1->from() == 1 && i1->to() == 2) continue;
3277
3278 if (i1->first() == Range::end()) {
3279 tty->print_cr("Interval %d has no Range", i1->reg_num()); i1->print(); tty->cr();
3280 has_error = true;
3281 }
3282
3283 for (Range* r = i1->first(); r != Range::end(); r = r->next()) {
3284 if (r->from() >= r->to()) {
3285 tty->print_cr("Interval %d has zero length range", i1->reg_num()); i1->print(); tty->cr();
3286 has_error = true;
3287 }
3288 }
3289
3290 for (int j = i + 1; j < len; j++) {
3291 Interval* i2 = interval_at(j);
3292 if (i2 == NULL || (i2->from() == 1 && i2->to() == 2)) continue;
3293
3294 int r1 = i1->assigned_reg();
3295 int r1Hi = i1->assigned_regHi();
3296 int r2 = i2->assigned_reg();
3297 int r2Hi = i2->assigned_regHi();
3298 if ((r1 == r2 || r1 == r2Hi || (r1Hi != any_reg && (r1Hi == r2 || r1Hi == r2Hi))) && i1->intersects(i2)) {
3299 tty->print_cr("Intervals %d and %d overlap and have the same register assigned", i1->reg_num(), i2->reg_num());
3300 i1->print(); tty->cr();
3301 i2->print(); tty->cr();
3302 has_error = true;
3303 }
3304 }
3305 }
3306
3307 assert(has_error == false, "register allocation invalid");
3308 }
3309
3310
3311 void LinearScan::verify_no_oops_in_fixed_intervals() {
3312 Interval* fixed_intervals;
3313 Interval* other_intervals;
3314 create_unhandled_lists(&fixed_intervals, &other_intervals, is_precolored_cpu_interval, NULL);
3315
3316 // to ensure a walking until the last instruction id, add a dummy interval
3317 // with a high operation id
3318 other_intervals = new Interval(any_reg);
3319 other_intervals->add_range(max_jint - 2, max_jint - 1);
3320 IntervalWalker* iw = new IntervalWalker(this, fixed_intervals, other_intervals);
3321
3322 LIR_OpVisitState visitor;
3323 for (int i = 0; i < block_count(); i++) {
3324 BlockBegin* block = block_at(i);
3325
3326 LIR_OpList* instructions = block->lir()->instructions_list();
3327
3328 for (int j = 0; j < instructions->length(); j++) {
3329 LIR_Op* op = instructions->at(j);
3330 int op_id = op->id();
3331
3332 visitor.visit(op);
3333
3334 if (visitor.info_count() > 0) {
3335 iw->walk_before(op->id());
3336 bool check_live = true;
3337 if (op->code() == lir_move) {
3338 LIR_Op1* move = (LIR_Op1*)op;
3339 check_live = (move->patch_code() == lir_patch_none);
3340 }
3341 LIR_OpBranch* branch = op->as_OpBranch();
3342 if (branch != NULL && branch->stub() != NULL && branch->stub()->is_exception_throw_stub()) {
3343 // Don't bother checking the stub in this case since the
3344 // exception stub will never return to normal control flow.
3345 check_live = false;
3346 }
3347
3348 // Make sure none of the fixed registers is live across an
3349 // oopmap since we can't handle that correctly.
3350 if (check_live) {
3351 for (Interval* interval = iw->active_first(fixedKind);
3352 interval != Interval::end();
3353 interval = interval->next()) {
3354 if (interval->current_to() > op->id() + 1) {
3355 // This interval is live out of this op so make sure
3356 // that this interval represents some value that's
3357 // referenced by this op either as an input or output.
3358 bool ok = false;
3359 for_each_visitor_mode(mode) {
3360 int n = visitor.opr_count(mode);
3361 for (int k = 0; k < n; k++) {
3362 LIR_Opr opr = visitor.opr_at(mode, k);
3363 if (opr->is_fixed_cpu()) {
3364 if (interval_at(reg_num(opr)) == interval) {
3365 ok = true;
3366 break;
3367 }
3368 int hi = reg_numHi(opr);
3369 if (hi != -1 && interval_at(hi) == interval) {
3370 ok = true;
3371 break;
3372 }
3373 }
3374 }
3375 }
3376 assert(ok, "fixed intervals should never be live across an oopmap point");
3377 }
3378 }
3379 }
3380 }
3381
3382 // oop-maps at calls do not contain registers, so check is not needed
3383 if (!visitor.has_call()) {
3384
3385 for_each_visitor_mode(mode) {
3386 int n = visitor.opr_count(mode);
3387 for (int k = 0; k < n; k++) {
3388 LIR_Opr opr = visitor.opr_at(mode, k);
3389
3390 if (opr->is_fixed_cpu() && opr->is_oop()) {
3391 // operand is a non-virtual cpu register and contains an oop
3392 TRACE_LINEAR_SCAN(4, op->print_on(tty); tty->print("checking operand "); opr->print(); tty->cr());
3393
3394 Interval* interval = interval_at(reg_num(opr));
3395 assert(interval != NULL, "no interval");
3396
3397 if (mode == LIR_OpVisitState::inputMode) {
3398 if (interval->to() >= op_id + 1) {
3399 assert(interval->to() < op_id + 2 ||
3400 interval->has_hole_between(op_id, op_id + 2),
3401 "oop input operand live after instruction");
3402 }
3403 } else if (mode == LIR_OpVisitState::outputMode) {
3404 if (interval->from() <= op_id - 1) {
3405 assert(interval->has_hole_between(op_id - 1, op_id),
3406 "oop input operand live after instruction");
3407 }
3408 }
3409 }
3410 }
3411 }
3412 }
3413 }
3414 }
3415 }
3416
3417
3418 void LinearScan::verify_constants() {
3419 int num_regs = num_virtual_regs();
3420 int size = live_set_size();
3421 int num_blocks = block_count();
3422
3423 for (int i = 0; i < num_blocks; i++) {
3424 BlockBegin* block = block_at(i);
3425 ResourceBitMap live_at_edge = block->live_in();
3426
3427 // visit all registers where the live_at_edge bit is set
3428 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)) {
3429 TRACE_LINEAR_SCAN(4, tty->print("checking interval %d of block B%d", r, block->block_id()));
3430
3431 Value value = gen()->instruction_for_vreg(r);
3432
3433 assert(value != NULL, "all intervals live across block boundaries must have Value");
3434 assert(value->operand()->is_register() && value->operand()->is_virtual(), "value must have virtual operand");
3435 assert(value->operand()->vreg_number() == r, "register number must match");
3436 // TKR assert(value->as_Constant() == NULL || value->is_pinned(), "only pinned constants can be alive accross block boundaries");
3437 }
3438 }
3439 }
3440
3441
3442 class RegisterVerifier: public StackObj {
3443 private:
3444 LinearScan* _allocator;
3445 BlockList _work_list; // all blocks that must be processed
3446 IntervalsList _saved_states; // saved information of previous check
3447
3448 // simplified access to methods of LinearScan
3449 Compilation* compilation() const { return _allocator->compilation(); }
3450 Interval* interval_at(int reg_num) const { return _allocator->interval_at(reg_num); }
3451 int reg_num(LIR_Opr opr) const { return _allocator->reg_num(opr); }
3452
3453 // currently, only registers are processed
3454 int state_size() { return LinearScan::nof_regs; }
3455
3456 // accessors
3457 IntervalList* state_for_block(BlockBegin* block) { return _saved_states.at(block->block_id()); }
3458 void set_state_for_block(BlockBegin* block, IntervalList* saved_state) { _saved_states.at_put(block->block_id(), saved_state); }
3459 void add_to_work_list(BlockBegin* block) { if (!_work_list.contains(block)) _work_list.append(block); }
3460
3461 // helper functions
3462 IntervalList* copy(IntervalList* input_state);
3463 void state_put(IntervalList* input_state, int reg, Interval* interval);
3464 bool check_state(IntervalList* input_state, int reg, Interval* interval);
3465
3466 void process_block(BlockBegin* block);
3467 void process_xhandler(XHandler* xhandler, IntervalList* input_state);
3468 void process_successor(BlockBegin* block, IntervalList* input_state);
3469 void process_operations(LIR_List* ops, IntervalList* input_state);
3470
3471 public:
3472 RegisterVerifier(LinearScan* allocator)
3473 : _allocator(allocator)
3474 , _work_list(16)
3475 , _saved_states(BlockBegin::number_of_blocks(), BlockBegin::number_of_blocks(), NULL)
3476 { }
3477
3478 void verify(BlockBegin* start);
3479 };
3480
3481
3482 // entry function from LinearScan that starts the verification
3483 void LinearScan::verify_registers() {
3484 RegisterVerifier verifier(this);
3485 verifier.verify(block_at(0));
3486 }
3487
3488
3489 void RegisterVerifier::verify(BlockBegin* start) {
3490 // setup input registers (method arguments) for first block
3491 int input_state_len = state_size();
3492 IntervalList* input_state = new IntervalList(input_state_len, input_state_len, NULL);
3493 CallingConvention* args = compilation()->frame_map()->incoming_arguments();
3494 for (int n = 0; n < args->length(); n++) {
3495 LIR_Opr opr = args->at(n);
3496 if (opr->is_register()) {
3497 Interval* interval = interval_at(reg_num(opr));
3498
3499 if (interval->assigned_reg() < state_size()) {
3500 input_state->at_put(interval->assigned_reg(), interval);
3501 }
3502 if (interval->assigned_regHi() != LinearScan::any_reg && interval->assigned_regHi() < state_size()) {
3503 input_state->at_put(interval->assigned_regHi(), interval);
3504 }
3505 }
3506 }
3507
3508 set_state_for_block(start, input_state);
3509 add_to_work_list(start);
3510
3511 // main loop for verification
3512 do {
3513 BlockBegin* block = _work_list.at(0);
3514 _work_list.remove_at(0);
3515
3516 process_block(block);
3517 } while (!_work_list.is_empty());
3518 }
3519
3520 void RegisterVerifier::process_block(BlockBegin* block) {
3521 TRACE_LINEAR_SCAN(2, tty->cr(); tty->print_cr("process_block B%d", block->block_id()));
3522
3523 // must copy state because it is modified
3524 IntervalList* input_state = copy(state_for_block(block));
3525
3526 if (TraceLinearScanLevel >= 4) {
3527 tty->print_cr("Input-State of intervals:");
3528 tty->print(" ");
3529 for (int i = 0; i < state_size(); i++) {
3530 if (input_state->at(i) != NULL) {
3531 tty->print(" %4d", input_state->at(i)->reg_num());
3532 } else {
3533 tty->print(" __");
3534 }
3535 }
3536 tty->cr();
3537 tty->cr();
3538 }
3539
3540 // process all operations of the block
3541 process_operations(block->lir(), input_state);
3542
3543 // iterate all successors
3544 for (int i = 0; i < block->number_of_sux(); i++) {
3545 process_successor(block->sux_at(i), input_state);
3546 }
3547 }
3548
3549 void RegisterVerifier::process_xhandler(XHandler* xhandler, IntervalList* input_state) {
3550 TRACE_LINEAR_SCAN(2, tty->print_cr("process_xhandler B%d", xhandler->entry_block()->block_id()));
3551
3552 // must copy state because it is modified
3553 input_state = copy(input_state);
3554
3555 if (xhandler->entry_code() != NULL) {
3556 process_operations(xhandler->entry_code(), input_state);
3557 }
3558 process_successor(xhandler->entry_block(), input_state);
3559 }
3560
3561 void RegisterVerifier::process_successor(BlockBegin* block, IntervalList* input_state) {
3562 IntervalList* saved_state = state_for_block(block);
3563
3564 if (saved_state != NULL) {
3565 // this block was already processed before.
3566 // check if new input_state is consistent with saved_state
3567
3568 bool saved_state_correct = true;
3569 for (int i = 0; i < state_size(); i++) {
3570 if (input_state->at(i) != saved_state->at(i)) {
3571 // current input_state and previous saved_state assume a different
3572 // interval in this register -> assume that this register is invalid
3573 if (saved_state->at(i) != NULL) {
3574 // invalidate old calculation only if it assumed that
3575 // register was valid. when the register was already invalid,
3576 // then the old calculation was correct.
3577 saved_state_correct = false;
3578 saved_state->at_put(i, NULL);
3579
3580 TRACE_LINEAR_SCAN(4, tty->print_cr("process_successor B%d: invalidating slot %d", block->block_id(), i));
3581 }
3582 }
3583 }
3584
3585 if (saved_state_correct) {
3586 // already processed block with correct input_state
3587 TRACE_LINEAR_SCAN(2, tty->print_cr("process_successor B%d: previous visit already correct", block->block_id()));
3588 } else {
3589 // must re-visit this block
3590 TRACE_LINEAR_SCAN(2, tty->print_cr("process_successor B%d: must re-visit because input state changed", block->block_id()));
3591 add_to_work_list(block);
3592 }
3593
3594 } else {
3595 // block was not processed before, so set initial input_state
3596 TRACE_LINEAR_SCAN(2, tty->print_cr("process_successor B%d: initial visit", block->block_id()));
3597
3598 set_state_for_block(block, copy(input_state));
3599 add_to_work_list(block);
3600 }
3601 }
3602
3603
3604 IntervalList* RegisterVerifier::copy(IntervalList* input_state) {
3605 IntervalList* copy_state = new IntervalList(input_state->length());
3606 copy_state->appendAll(input_state);
3607 return copy_state;
3608 }
3609
3610 void RegisterVerifier::state_put(IntervalList* input_state, int reg, Interval* interval) {
3611 if (reg != LinearScan::any_reg && reg < state_size()) {
3612 if (interval != NULL) {
3613 TRACE_LINEAR_SCAN(4, tty->print_cr(" reg[%d] = %d", reg, interval->reg_num()));
3614 } else if (input_state->at(reg) != NULL) {
3615 TRACE_LINEAR_SCAN(4, tty->print_cr(" reg[%d] = NULL", reg));
3616 }
3617
3618 input_state->at_put(reg, interval);
3619 }
3620 }
3621
3622 bool RegisterVerifier::check_state(IntervalList* input_state, int reg, Interval* interval) {
3623 if (reg != LinearScan::any_reg && reg < state_size()) {
3624 if (input_state->at(reg) != interval) {
3625 tty->print_cr("!! Error in register allocation: register %d does not contain interval %d", reg, interval->reg_num());
3626 return true;
3627 }
3628 }
3629 return false;
3630 }
3631
3632 void RegisterVerifier::process_operations(LIR_List* ops, IntervalList* input_state) {
3633 // visit all instructions of the block
3634 LIR_OpVisitState visitor;
3635 bool has_error = false;
3636
3637 for (int i = 0; i < ops->length(); i++) {
3638 LIR_Op* op = ops->at(i);
3639 visitor.visit(op);
3640
3641 TRACE_LINEAR_SCAN(4, op->print_on(tty));
3642
3643 // check if input operands are correct
3644 int j;
3645 int n = visitor.opr_count(LIR_OpVisitState::inputMode);
3646 for (j = 0; j < n; j++) {
3647 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::inputMode, j);
3648 if (opr->is_register() && LinearScan::is_processed_reg_num(reg_num(opr))) {
3649 Interval* interval = interval_at(reg_num(opr));
3650 if (op->id() != -1) {
3651 interval = interval->split_child_at_op_id(op->id(), LIR_OpVisitState::inputMode);
3652 }
3653
3654 has_error |= check_state(input_state, interval->assigned_reg(), interval->split_parent());
3655 has_error |= check_state(input_state, interval->assigned_regHi(), interval->split_parent());
3656
3657 // When an operand is marked with is_last_use, then the fpu stack allocator
3658 // removes the register from the fpu stack -> the register contains no value
3659 if (opr->is_last_use()) {
3660 state_put(input_state, interval->assigned_reg(), NULL);
3661 state_put(input_state, interval->assigned_regHi(), NULL);
3662 }
3663 }
3664 }
3665
3666 // invalidate all caller save registers at calls
3667 if (visitor.has_call()) {
3668 for (j = 0; j < FrameMap::nof_caller_save_cpu_regs(); j++) {
3669 state_put(input_state, reg_num(FrameMap::caller_save_cpu_reg_at(j)), NULL);
3670 }
3671 for (j = 0; j < FrameMap::nof_caller_save_fpu_regs; j++) {
3672 state_put(input_state, reg_num(FrameMap::caller_save_fpu_reg_at(j)), NULL);
3673 }
3674
3675 #ifdef X86
3676 int num_caller_save_xmm_regs = FrameMap::get_num_caller_save_xmms();
3677 for (j = 0; j < num_caller_save_xmm_regs; j++) {
3678 state_put(input_state, reg_num(FrameMap::caller_save_xmm_reg_at(j)), NULL);
3679 }
3680 #endif
3681 }
3682
3683 // process xhandler before output and temp operands
3684 XHandlers* xhandlers = visitor.all_xhandler();
3685 n = xhandlers->length();
3686 for (int k = 0; k < n; k++) {
3687 process_xhandler(xhandlers->handler_at(k), input_state);
3688 }
3689
3690 // set temp operands (some operations use temp operands also as output operands, so can't set them NULL)
3691 n = visitor.opr_count(LIR_OpVisitState::tempMode);
3692 for (j = 0; j < n; j++) {
3693 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::tempMode, j);
3694 if (opr->is_register() && LinearScan::is_processed_reg_num(reg_num(opr))) {
3695 Interval* interval = interval_at(reg_num(opr));
3696 if (op->id() != -1) {
3697 interval = interval->split_child_at_op_id(op->id(), LIR_OpVisitState::tempMode);
3698 }
3699
3700 state_put(input_state, interval->assigned_reg(), interval->split_parent());
3701 state_put(input_state, interval->assigned_regHi(), interval->split_parent());
3702 }
3703 }
3704
3705 // set output operands
3706 n = visitor.opr_count(LIR_OpVisitState::outputMode);
3707 for (j = 0; j < n; j++) {
3708 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::outputMode, j);
3709 if (opr->is_register() && LinearScan::is_processed_reg_num(reg_num(opr))) {
3710 Interval* interval = interval_at(reg_num(opr));
3711 if (op->id() != -1) {
3712 interval = interval->split_child_at_op_id(op->id(), LIR_OpVisitState::outputMode);
3713 }
3714
3715 state_put(input_state, interval->assigned_reg(), interval->split_parent());
3716 state_put(input_state, interval->assigned_regHi(), interval->split_parent());
3717 }
3718 }
3719 }
3720 assert(has_error == false, "Error in register allocation");
3721 }
3722
3723 #endif // ASSERT
3724
3725
3726
3727 // **** Implementation of MoveResolver ******************************
3728
3729 MoveResolver::MoveResolver(LinearScan* allocator) :
3730 _allocator(allocator),
3731 _insert_list(NULL),
3732 _insert_idx(-1),
3733 _insertion_buffer(),
3734 _mapping_from(8),
3735 _mapping_from_opr(8),
3736 _mapping_to(8),
3737 _multiple_reads_allowed(false)
3738 {
3739 for (int i = 0; i < LinearScan::nof_regs; i++) {
3740 _register_blocked[i] = 0;
3741 }
3742 DEBUG_ONLY(check_empty());
3743 }
3744
3745
3746 #ifdef ASSERT
3747
3748 void MoveResolver::check_empty() {
3749 assert(_mapping_from.length() == 0 && _mapping_from_opr.length() == 0 && _mapping_to.length() == 0, "list must be empty before and after processing");
3750 for (int i = 0; i < LinearScan::nof_regs; i++) {
3751 assert(register_blocked(i) == 0, "register map must be empty before and after processing");
3752 }
3753 assert(_multiple_reads_allowed == false, "must have default value");
3754 }
3755
3756 void MoveResolver::verify_before_resolve() {
3757 assert(_mapping_from.length() == _mapping_from_opr.length(), "length must be equal");
3758 assert(_mapping_from.length() == _mapping_to.length(), "length must be equal");
3759 assert(_insert_list != NULL && _insert_idx != -1, "insert position not set");
3760
3761 int i, j;
3762 if (!_multiple_reads_allowed) {
3763 for (i = 0; i < _mapping_from.length(); i++) {
3764 for (j = i + 1; j < _mapping_from.length(); j++) {
3765 assert(_mapping_from.at(i) == NULL || _mapping_from.at(i) != _mapping_from.at(j), "cannot read from same interval twice");
3766 }
3767 }
3768 }
3769
3770 for (i = 0; i < _mapping_to.length(); i++) {
3771 for (j = i + 1; j < _mapping_to.length(); j++) {
3772 assert(_mapping_to.at(i) != _mapping_to.at(j), "cannot write to same interval twice");
3773 }
3774 }
3775
3776
3777 ResourceBitMap used_regs(LinearScan::nof_regs + allocator()->frame_map()->argcount() + allocator()->max_spills());
3778 if (!_multiple_reads_allowed) {
3779 for (i = 0; i < _mapping_from.length(); i++) {
3780 Interval* it = _mapping_from.at(i);
3781 if (it != NULL) {
3782 assert(!used_regs.at(it->assigned_reg()), "cannot read from same register twice");
3783 used_regs.set_bit(it->assigned_reg());
3784
3785 if (it->assigned_regHi() != LinearScan::any_reg) {
3786 assert(!used_regs.at(it->assigned_regHi()), "cannot read from same register twice");
3787 used_regs.set_bit(it->assigned_regHi());
3788 }
3789 }
3790 }
3791 }
3792
3793 used_regs.clear();
3794 for (i = 0; i < _mapping_to.length(); i++) {
3795 Interval* it = _mapping_to.at(i);
3796 assert(!used_regs.at(it->assigned_reg()), "cannot write to same register twice");
3797 used_regs.set_bit(it->assigned_reg());
3798
3799 if (it->assigned_regHi() != LinearScan::any_reg) {
3800 assert(!used_regs.at(it->assigned_regHi()), "cannot write to same register twice");
3801 used_regs.set_bit(it->assigned_regHi());
3802 }
3803 }
3804
3805 used_regs.clear();
3806 for (i = 0; i < _mapping_from.length(); i++) {
3807 Interval* it = _mapping_from.at(i);
3808 if (it != NULL && it->assigned_reg() >= LinearScan::nof_regs) {
3809 used_regs.set_bit(it->assigned_reg());
3810 }
3811 }
3812 for (i = 0; i < _mapping_to.length(); i++) {
3813 Interval* it = _mapping_to.at(i);
3814 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");
3815 }
3816 }
3817
3818 #endif // ASSERT
3819
3820
3821 // mark assigned_reg and assigned_regHi of the interval as blocked
3822 void MoveResolver::block_registers(Interval* it) {
3823 int reg = it->assigned_reg();
3824 if (reg < LinearScan::nof_regs) {
3825 assert(_multiple_reads_allowed || register_blocked(reg) == 0, "register already marked as used");
3826 set_register_blocked(reg, 1);
3827 }
3828 reg = it->assigned_regHi();
3829 if (reg != LinearScan::any_reg && reg < LinearScan::nof_regs) {
3830 assert(_multiple_reads_allowed || register_blocked(reg) == 0, "register already marked as used");
3831 set_register_blocked(reg, 1);
3832 }
3833 }
3834
3835 // mark assigned_reg and assigned_regHi of the interval as unblocked
3836 void MoveResolver::unblock_registers(Interval* it) {
3837 int reg = it->assigned_reg();
3838 if (reg < LinearScan::nof_regs) {
3839 assert(register_blocked(reg) > 0, "register already marked as unused");
3840 set_register_blocked(reg, -1);
3841 }
3842 reg = it->assigned_regHi();
3843 if (reg != LinearScan::any_reg && reg < LinearScan::nof_regs) {
3844 assert(register_blocked(reg) > 0, "register already marked as unused");
3845 set_register_blocked(reg, -1);
3846 }
3847 }
3848
3849 // check if assigned_reg and assigned_regHi of the to-interval are not blocked (or only blocked by from)
3850 bool MoveResolver::save_to_process_move(Interval* from, Interval* to) {
3851 int from_reg = -1;
3852 int from_regHi = -1;
3853 if (from != NULL) {
3854 from_reg = from->assigned_reg();
3855 from_regHi = from->assigned_regHi();
3856 }
3857
3858 int reg = to->assigned_reg();
3859 if (reg < LinearScan::nof_regs) {
3860 if (register_blocked(reg) > 1 || (register_blocked(reg) == 1 && reg != from_reg && reg != from_regHi)) {
3861 return false;
3862 }
3863 }
3864 reg = to->assigned_regHi();
3865 if (reg != LinearScan::any_reg && reg < LinearScan::nof_regs) {
3866 if (register_blocked(reg) > 1 || (register_blocked(reg) == 1 && reg != from_reg && reg != from_regHi)) {
3867 return false;
3868 }
3869 }
3870
3871 return true;
3872 }
3873
3874
3875 void MoveResolver::create_insertion_buffer(LIR_List* list) {
3876 assert(!_insertion_buffer.initialized(), "overwriting existing buffer");
3877 _insertion_buffer.init(list);
3878 }
3879
3880 void MoveResolver::append_insertion_buffer() {
3881 if (_insertion_buffer.initialized()) {
3882 _insertion_buffer.lir_list()->append(&_insertion_buffer);
3883 }
3884 assert(!_insertion_buffer.initialized(), "must be uninitialized now");
3885
3886 _insert_list = NULL;
3887 _insert_idx = -1;
3888 }
3889
3890 void MoveResolver::insert_move(Interval* from_interval, Interval* to_interval) {
3891 assert(from_interval->reg_num() != to_interval->reg_num(), "from and to interval equal");
3892 assert(from_interval->type() == to_interval->type(), "move between different types");
3893 assert(_insert_list != NULL && _insert_idx != -1, "must setup insert position first");
3894 assert(_insertion_buffer.lir_list() == _insert_list, "wrong insertion buffer");
3895
3896 LIR_Opr from_opr = LIR_OprFact::virtual_register(from_interval->reg_num(), from_interval->type());
3897 LIR_Opr to_opr = LIR_OprFact::virtual_register(to_interval->reg_num(), to_interval->type());
3898
3899 if (!_multiple_reads_allowed) {
3900 // the last_use flag is an optimization for FPU stack allocation. When the same
3901 // input interval is used in more than one move, then it is too difficult to determine
3902 // if this move is really the last use.
3903 from_opr = from_opr->make_last_use();
3904 }
3905 _insertion_buffer.move(_insert_idx, from_opr, to_opr);
3906
3907 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()));
3908 }
3909
3910 void MoveResolver::insert_move(LIR_Opr from_opr, Interval* to_interval) {
3911 assert(from_opr->type() == to_interval->type(), "move between different types");
3912 assert(_insert_list != NULL && _insert_idx != -1, "must setup insert position first");
3913 assert(_insertion_buffer.lir_list() == _insert_list, "wrong insertion buffer");
3914
3915 LIR_Opr to_opr = LIR_OprFact::virtual_register(to_interval->reg_num(), to_interval->type());
3916 _insertion_buffer.move(_insert_idx, from_opr, to_opr);
3917
3918 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()));
3919 }
3920
3921
3922 void MoveResolver::resolve_mappings() {
3923 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));
3924 DEBUG_ONLY(verify_before_resolve());
3925
3926 // Block all registers that are used as input operands of a move.
3927 // When a register is blocked, no move to this register is emitted.
3928 // This is necessary for detecting cycles in moves.
3929 int i;
3930 for (i = _mapping_from.length() - 1; i >= 0; i--) {
3931 Interval* from_interval = _mapping_from.at(i);
3932 if (from_interval != NULL) {
3933 block_registers(from_interval);
3934 }
3935 }
3936
3937 int spill_candidate = -1;
3938 while (_mapping_from.length() > 0) {
3939 bool processed_interval = false;
3940
3941 for (i = _mapping_from.length() - 1; i >= 0; i--) {
3942 Interval* from_interval = _mapping_from.at(i);
3943 Interval* to_interval = _mapping_to.at(i);
3944
3945 if (save_to_process_move(from_interval, to_interval)) {
3946 // this inverval can be processed because target is free
3947 if (from_interval != NULL) {
3948 insert_move(from_interval, to_interval);
3949 unblock_registers(from_interval);
3950 } else {
3951 insert_move(_mapping_from_opr.at(i), to_interval);
3952 }
3953 _mapping_from.remove_at(i);
3954 _mapping_from_opr.remove_at(i);
3955 _mapping_to.remove_at(i);
3956
3957 processed_interval = true;
3958 } else if (from_interval != NULL && from_interval->assigned_reg() < LinearScan::nof_regs) {
3959 // this interval cannot be processed now because target is not free
3960 // it starts in a register, so it is a possible candidate for spilling
3961 spill_candidate = i;
3962 }
3963 }
3964
3965 if (!processed_interval) {
3966 // no move could be processed because there is a cycle in the move list
3967 // (e.g. r1 -> r2, r2 -> r1), so one interval must be spilled to memory
3968 guarantee(spill_candidate != -1, "no interval in register for spilling found");
3969
3970 // create a new spill interval and assign a stack slot to it
3971 Interval* from_interval = _mapping_from.at(spill_candidate);
3972 Interval* spill_interval = new Interval(-1);
3973 spill_interval->set_type(from_interval->type());
3974
3975 // add a dummy range because real position is difficult to calculate
3976 // Note: this range is a special case when the integrity of the allocation is checked
3977 spill_interval->add_range(1, 2);
3978
3979 // do not allocate a new spill slot for temporary interval, but
3980 // use spill slot assigned to from_interval. Otherwise moves from
3981 // one stack slot to another can happen (not allowed by LIR_Assembler
3982 int spill_slot = from_interval->canonical_spill_slot();
3983 if (spill_slot < 0) {
3984 spill_slot = allocator()->allocate_spill_slot(type2spill_size[spill_interval->type()] == 2);
3985 from_interval->set_canonical_spill_slot(spill_slot);
3986 }
3987 spill_interval->assign_reg(spill_slot);
3988 allocator()->append_interval(spill_interval);
3989
3990 TRACE_LINEAR_SCAN(4, tty->print_cr("created new Interval %d for spilling", spill_interval->reg_num()));
3991
3992 // insert a move from register to stack and update the mapping
3993 insert_move(from_interval, spill_interval);
3994 _mapping_from.at_put(spill_candidate, spill_interval);
3995 unblock_registers(from_interval);
3996 }
3997 }
3998
3999 // reset to default value
4000 _multiple_reads_allowed = false;
4001
4002 // check that all intervals have been processed
4003 DEBUG_ONLY(check_empty());
4004 }
4005
4006
4007 void MoveResolver::set_insert_position(LIR_List* insert_list, int insert_idx) {
4008 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));
4009 assert(_insert_list == NULL && _insert_idx == -1, "use move_insert_position instead of set_insert_position when data already set");
4010
4011 create_insertion_buffer(insert_list);
4012 _insert_list = insert_list;
4013 _insert_idx = insert_idx;
4014 }
4015
4016 void MoveResolver::move_insert_position(LIR_List* insert_list, int insert_idx) {
4017 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));
4018
4019 if (_insert_list != NULL && (insert_list != _insert_list || insert_idx != _insert_idx)) {
4020 // insert position changed -> resolve current mappings
4021 resolve_mappings();
4022 }
4023
4024 if (insert_list != _insert_list) {
4025 // block changed -> append insertion_buffer because it is
4026 // bound to a specific block and create a new insertion_buffer
4027 append_insertion_buffer();
4028 create_insertion_buffer(insert_list);
4029 }
4030
4031 _insert_list = insert_list;
4032 _insert_idx = insert_idx;
4033 }
4034
4035 void MoveResolver::add_mapping(Interval* from_interval, Interval* to_interval) {
4036 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()));
4037
4038 _mapping_from.append(from_interval);
4039 _mapping_from_opr.append(LIR_OprFact::illegalOpr);
4040 _mapping_to.append(to_interval);
4041 }
4042
4043
4044 void MoveResolver::add_mapping(LIR_Opr from_opr, Interval* to_interval) {
4045 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()));
4046 assert(from_opr->is_constant(), "only for constants");
4047
4048 _mapping_from.append(NULL);
4049 _mapping_from_opr.append(from_opr);
4050 _mapping_to.append(to_interval);
4051 }
4052
4053 void MoveResolver::resolve_and_append_moves() {
4054 if (has_mappings()) {
4055 resolve_mappings();
4056 }
4057 append_insertion_buffer();
4058 }
4059
4060
4061
4062 // **** Implementation of Range *************************************
4063
4064 Range::Range(int from, int to, Range* next) :
4065 _from(from),
4066 _to(to),
4067 _next(next)
4068 {
4069 }
4070
4071 // initialize sentinel
4072 Range* Range::_end = NULL;
4073 void Range::initialize(Arena* arena) {
4074 _end = new (arena) Range(max_jint, max_jint, NULL);
4075 }
4076
4077 int Range::intersects_at(Range* r2) const {
4078 const Range* r1 = this;
4079
4080 assert(r1 != NULL && r2 != NULL, "null ranges not allowed");
4081 assert(r1 != _end && r2 != _end, "empty ranges not allowed");
4082
4083 do {
4084 if (r1->from() < r2->from()) {
4085 if (r1->to() <= r2->from()) {
4086 r1 = r1->next(); if (r1 == _end) return -1;
4087 } else {
4088 return r2->from();
4089 }
4090 } else if (r2->from() < r1->from()) {
4091 if (r2->to() <= r1->from()) {
4092 r2 = r2->next(); if (r2 == _end) return -1;
4093 } else {
4094 return r1->from();
4095 }
4096 } else { // r1->from() == r2->from()
4097 if (r1->from() == r1->to()) {
4098 r1 = r1->next(); if (r1 == _end) return -1;
4099 } else if (r2->from() == r2->to()) {
4100 r2 = r2->next(); if (r2 == _end) return -1;
4101 } else {
4102 return r1->from();
4103 }
4104 }
4105 } while (true);
4106 }
4107
4108 #ifndef PRODUCT
4109 void Range::print(outputStream* out) const {
4110 out->print("[%d, %d[ ", _from, _to);
4111 }
4112 #endif
4113
4114
4115
4116 // **** Implementation of Interval **********************************
4117
4118 // initialize sentinel
4119 Interval* Interval::_end = NULL;
4120 void Interval::initialize(Arena* arena) {
4121 Range::initialize(arena);
4122 _end = new (arena) Interval(-1);
4123 }
4124
4125 Interval::Interval(int reg_num) :
4126 _reg_num(reg_num),
4127 _type(T_ILLEGAL),
4128 _first(Range::end()),
4129 _use_pos_and_kinds(12),
4130 _current(Range::end()),
4131 _next(_end),
4132 _state(invalidState),
4133 _assigned_reg(LinearScan::any_reg),
4134 _assigned_regHi(LinearScan::any_reg),
4135 _cached_to(-1),
4136 _cached_opr(LIR_OprFact::illegalOpr),
4137 _cached_vm_reg(VMRegImpl::Bad()),
4138 _split_children(NULL),
4139 _canonical_spill_slot(-1),
4140 _insert_move_when_activated(false),
4141 _spill_state(noDefinitionFound),
4142 _spill_definition_pos(-1),
4143 _register_hint(NULL)
4144 {
4145 _split_parent = this;
4146 _current_split_child = this;
4147 }
4148
4149 int Interval::calc_to() {
4150 assert(_first != Range::end(), "interval has no range");
4151
4152 Range* r = _first;
4153 while (r->next() != Range::end()) {
4154 r = r->next();
4155 }
4156 return r->to();
4157 }
4158
4159
4160 #ifdef ASSERT
4161 // consistency check of split-children
4162 void Interval::check_split_children() {
4163 if (_split_children != NULL && _split_children->length() > 0) {
4164 assert(is_split_parent(), "only split parents can have children");
4165
4166 for (int i = 0; i < _split_children->length(); i++) {
4167 Interval* i1 = _split_children->at(i);
4168
4169 assert(i1->split_parent() == this, "not a split child of this interval");
4170 assert(i1->type() == type(), "must be equal for all split children");
4171 assert(i1->canonical_spill_slot() == canonical_spill_slot(), "must be equal for all split children");
4172
4173 for (int j = i + 1; j < _split_children->length(); j++) {
4174 Interval* i2 = _split_children->at(j);
4175
4176 assert(i1->reg_num() != i2->reg_num(), "same register number");
4177
4178 if (i1->from() < i2->from()) {
4179 assert(i1->to() <= i2->from() && i1->to() < i2->to(), "intervals overlapping");
4180 } else {
4181 assert(i2->from() < i1->from(), "intervals start at same op_id");
4182 assert(i2->to() <= i1->from() && i2->to() < i1->to(), "intervals overlapping");
4183 }
4184 }
4185 }
4186 }
4187 }
4188 #endif // ASSERT
4189
4190 Interval* Interval::register_hint(bool search_split_child) const {
4191 if (!search_split_child) {
4192 return _register_hint;
4193 }
4194
4195 if (_register_hint != NULL) {
4196 assert(_register_hint->is_split_parent(), "ony split parents are valid hint registers");
4197
4198 if (_register_hint->assigned_reg() >= 0 && _register_hint->assigned_reg() < LinearScan::nof_regs) {
4199 return _register_hint;
4200
4201 } else if (_register_hint->_split_children != NULL && _register_hint->_split_children->length() > 0) {
4202 // search the first split child that has a register assigned
4203 int len = _register_hint->_split_children->length();
4204 for (int i = 0; i < len; i++) {
4205 Interval* cur = _register_hint->_split_children->at(i);
4206
4207 if (cur->assigned_reg() >= 0 && cur->assigned_reg() < LinearScan::nof_regs) {
4208 return cur;
4209 }
4210 }
4211 }
4212 }
4213
4214 // no hint interval found that has a register assigned
4215 return NULL;
4216 }
4217
4218
4219 Interval* Interval::split_child_at_op_id(int op_id, LIR_OpVisitState::OprMode mode) {
4220 assert(is_split_parent(), "can only be called for split parents");
4221 assert(op_id >= 0, "invalid op_id (method can not be called for spill moves)");
4222
4223 Interval* result;
4224 if (_split_children == NULL || _split_children->length() == 0) {
4225 result = this;
4226 } else {
4227 result = NULL;
4228 int len = _split_children->length();
4229
4230 // in outputMode, the end of the interval (op_id == cur->to()) is not valid
4231 int to_offset = (mode == LIR_OpVisitState::outputMode ? 0 : 1);
4232
4233 int i;
4234 for (i = 0; i < len; i++) {
4235 Interval* cur = _split_children->at(i);
4236 if (cur->from() <= op_id && op_id < cur->to() + to_offset) {
4237 if (i > 0) {
4238 // exchange current split child to start of list (faster access for next call)
4239 _split_children->at_put(i, _split_children->at(0));
4240 _split_children->at_put(0, cur);
4241 }
4242
4243 // interval found
4244 result = cur;
4245 break;
4246 }
4247 }
4248
4249 #ifdef ASSERT
4250 for (i = 0; i < len; i++) {
4251 Interval* tmp = _split_children->at(i);
4252 if (tmp != result && tmp->from() <= op_id && op_id < tmp->to() + to_offset) {
4253 tty->print_cr("two valid result intervals found for op_id %d: %d and %d", op_id, result->reg_num(), tmp->reg_num());
4254 result->print();
4255 tmp->print();
4256 assert(false, "two valid result intervals found");
4257 }
4258 }
4259 #endif
4260 }
4261
4262 assert(result != NULL, "no matching interval found");
4263 assert(result->covers(op_id, mode), "op_id not covered by interval");
4264
4265 return result;
4266 }
4267
4268
4269 // returns the last split child that ends before the given op_id
4270 Interval* Interval::split_child_before_op_id(int op_id) {
4271 assert(op_id >= 0, "invalid op_id");
4272
4273 Interval* parent = split_parent();
4274 Interval* result = NULL;
4275
4276 assert(parent->_split_children != NULL, "no split children available");
4277 int len = parent->_split_children->length();
4278 assert(len > 0, "no split children available");
4279
4280 for (int i = len - 1; i >= 0; i--) {
4281 Interval* cur = parent->_split_children->at(i);
4282 if (cur->to() <= op_id && (result == NULL || result->to() < cur->to())) {
4283 result = cur;
4284 }
4285 }
4286
4287 assert(result != NULL, "no split child found");
4288 return result;
4289 }
4290
4291
4292 // Note: use positions are sorted descending -> first use has highest index
4293 int Interval::first_usage(IntervalUseKind min_use_kind) const {
4294 assert(LinearScan::is_virtual_interval(this), "cannot access use positions for fixed intervals");
4295
4296 for (int i = _use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
4297 if (_use_pos_and_kinds.at(i + 1) >= min_use_kind) {
4298 return _use_pos_and_kinds.at(i);
4299 }
4300 }
4301 return max_jint;
4302 }
4303
4304 int Interval::next_usage(IntervalUseKind min_use_kind, int from) const {
4305 assert(LinearScan::is_virtual_interval(this), "cannot access use positions for fixed intervals");
4306
4307 for (int i = _use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
4308 if (_use_pos_and_kinds.at(i) >= from && _use_pos_and_kinds.at(i + 1) >= min_use_kind) {
4309 return _use_pos_and_kinds.at(i);
4310 }
4311 }
4312 return max_jint;
4313 }
4314
4315 int Interval::next_usage_exact(IntervalUseKind exact_use_kind, int from) const {
4316 assert(LinearScan::is_virtual_interval(this), "cannot access use positions for fixed intervals");
4317
4318 for (int i = _use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
4319 if (_use_pos_and_kinds.at(i) >= from && _use_pos_and_kinds.at(i + 1) == exact_use_kind) {
4320 return _use_pos_and_kinds.at(i);
4321 }
4322 }
4323 return max_jint;
4324 }
4325
4326 int Interval::previous_usage(IntervalUseKind min_use_kind, int from) const {
4327 assert(LinearScan::is_virtual_interval(this), "cannot access use positions for fixed intervals");
4328
4329 int prev = 0;
4330 for (int i = _use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
4331 if (_use_pos_and_kinds.at(i) > from) {
4332 return prev;
4333 }
4334 if (_use_pos_and_kinds.at(i + 1) >= min_use_kind) {
4335 prev = _use_pos_and_kinds.at(i);
4336 }
4337 }
4338 return prev;
4339 }
4340
4341 void Interval::add_use_pos(int pos, IntervalUseKind use_kind) {
4342 assert(covers(pos, LIR_OpVisitState::inputMode), "use position not covered by live range");
4343
4344 // do not add use positions for precolored intervals because
4345 // they are never used
4346 if (use_kind != noUse && reg_num() >= LIR_OprDesc::vreg_base) {
4347 #ifdef ASSERT
4348 assert(_use_pos_and_kinds.length() % 2 == 0, "must be");
4349 for (int i = 0; i < _use_pos_and_kinds.length(); i += 2) {
4350 assert(pos <= _use_pos_and_kinds.at(i), "already added a use-position with lower position");
4351 assert(_use_pos_and_kinds.at(i + 1) >= firstValidKind && _use_pos_and_kinds.at(i + 1) <= lastValidKind, "invalid use kind");
4352 if (i > 0) {
4353 assert(_use_pos_and_kinds.at(i) < _use_pos_and_kinds.at(i - 2), "not sorted descending");
4354 }
4355 }
4356 #endif
4357
4358 // Note: add_use is called in descending order, so list gets sorted
4359 // automatically by just appending new use positions
4360 int len = _use_pos_and_kinds.length();
4361 if (len == 0 || _use_pos_and_kinds.at(len - 2) > pos) {
4362 _use_pos_and_kinds.append(pos);
4363 _use_pos_and_kinds.append(use_kind);
4364 } else if (_use_pos_and_kinds.at(len - 1) < use_kind) {
4365 assert(_use_pos_and_kinds.at(len - 2) == pos, "list not sorted correctly");
4366 _use_pos_and_kinds.at_put(len - 1, use_kind);
4367 }
4368 }
4369 }
4370
4371 void Interval::add_range(int from, int to) {
4372 assert(from < to, "invalid range");
4373 assert(first() == Range::end() || to < first()->next()->from(), "not inserting at begin of interval");
4374 assert(from <= first()->to(), "not inserting at begin of interval");
4375
4376 if (first()->from() <= to) {
4377 // join intersecting ranges
4378 first()->set_from(MIN2(from, first()->from()));
4379 first()->set_to (MAX2(to, first()->to()));
4380 } else {
4381 // insert new range
4382 _first = new Range(from, to, first());
4383 }
4384 }
4385
4386 Interval* Interval::new_split_child() {
4387 // allocate new interval
4388 Interval* result = new Interval(-1);
4389 result->set_type(type());
4390
4391 Interval* parent = split_parent();
4392 result->_split_parent = parent;
4393 result->set_register_hint(parent);
4394
4395 // insert new interval in children-list of parent
4396 if (parent->_split_children == NULL) {
4397 assert(is_split_parent(), "list must be initialized at first split");
4398
4399 parent->_split_children = new IntervalList(4);
4400 parent->_split_children->append(this);
4401 }
4402 parent->_split_children->append(result);
4403
4404 return result;
4405 }
4406
4407 // split this interval at the specified position and return
4408 // the remainder as a new interval.
4409 //
4410 // when an interval is split, a bi-directional link is established between the original interval
4411 // (the split parent) and the intervals that are split off this interval (the split children)
4412 // When a split child is split again, the new created interval is also a direct child
4413 // of the original parent (there is no tree of split children stored, but a flat list)
4414 // All split children are spilled to the same stack slot (stored in _canonical_spill_slot)
4415 //
4416 // Note: The new interval has no valid reg_num
4417 Interval* Interval::split(int split_pos) {
4418 assert(LinearScan::is_virtual_interval(this), "cannot split fixed intervals");
4419
4420 // allocate new interval
4421 Interval* result = new_split_child();
4422
4423 // split the ranges
4424 Range* prev = NULL;
4425 Range* cur = _first;
4426 while (cur != Range::end() && cur->to() <= split_pos) {
4427 prev = cur;
4428 cur = cur->next();
4429 }
4430 assert(cur != Range::end(), "split interval after end of last range");
4431
4432 if (cur->from() < split_pos) {
4433 result->_first = new Range(split_pos, cur->to(), cur->next());
4434 cur->set_to(split_pos);
4435 cur->set_next(Range::end());
4436
4437 } else {
4438 assert(prev != NULL, "split before start of first range");
4439 result->_first = cur;
4440 prev->set_next(Range::end());
4441 }
4442 result->_current = result->_first;
4443 _cached_to = -1; // clear cached value
4444
4445 // split list of use positions
4446 int total_len = _use_pos_and_kinds.length();
4447 int start_idx = total_len - 2;
4448 while (start_idx >= 0 && _use_pos_and_kinds.at(start_idx) < split_pos) {
4449 start_idx -= 2;
4450 }
4451
4452 intStack new_use_pos_and_kinds(total_len - start_idx);
4453 int i;
4454 for (i = start_idx + 2; i < total_len; i++) {
4455 new_use_pos_and_kinds.append(_use_pos_and_kinds.at(i));
4456 }
4457
4458 _use_pos_and_kinds.trunc_to(start_idx + 2);
4459 result->_use_pos_and_kinds = _use_pos_and_kinds;
4460 _use_pos_and_kinds = new_use_pos_and_kinds;
4461
4462 #ifdef ASSERT
4463 assert(_use_pos_and_kinds.length() % 2 == 0, "must have use kind for each use pos");
4464 assert(result->_use_pos_and_kinds.length() % 2 == 0, "must have use kind for each use pos");
4465 assert(_use_pos_and_kinds.length() + result->_use_pos_and_kinds.length() == total_len, "missed some entries");
4466
4467 for (i = 0; i < _use_pos_and_kinds.length(); i += 2) {
4468 assert(_use_pos_and_kinds.at(i) < split_pos, "must be");
4469 assert(_use_pos_and_kinds.at(i + 1) >= firstValidKind && _use_pos_and_kinds.at(i + 1) <= lastValidKind, "invalid use kind");
4470 }
4471 for (i = 0; i < result->_use_pos_and_kinds.length(); i += 2) {
4472 assert(result->_use_pos_and_kinds.at(i) >= split_pos, "must be");
4473 assert(result->_use_pos_and_kinds.at(i + 1) >= firstValidKind && result->_use_pos_and_kinds.at(i + 1) <= lastValidKind, "invalid use kind");
4474 }
4475 #endif
4476
4477 return result;
4478 }
4479
4480 // split this interval at the specified position and return
4481 // the head as a new interval (the original interval is the tail)
4482 //
4483 // Currently, only the first range can be split, and the new interval
4484 // must not have split positions
4485 Interval* Interval::split_from_start(int split_pos) {
4486 assert(LinearScan::is_virtual_interval(this), "cannot split fixed intervals");
4487 assert(split_pos > from() && split_pos < to(), "can only split inside interval");
4488 assert(split_pos > _first->from() && split_pos <= _first->to(), "can only split inside first range");
4489 assert(first_usage(noUse) > split_pos, "can not split when use positions are present");
4490
4491 // allocate new interval
4492 Interval* result = new_split_child();
4493
4494 // the new created interval has only one range (checked by assertion above),
4495 // so the splitting of the ranges is very simple
4496 result->add_range(_first->from(), split_pos);
4497
4498 if (split_pos == _first->to()) {
4499 assert(_first->next() != Range::end(), "must not be at end");
4500 _first = _first->next();
4501 } else {
4502 _first->set_from(split_pos);
4503 }
4504
4505 return result;
4506 }
4507
4508
4509 // returns true if the op_id is inside the interval
4510 bool Interval::covers(int op_id, LIR_OpVisitState::OprMode mode) const {
4511 Range* cur = _first;
4512
4513 while (cur != Range::end() && cur->to() < op_id) {
4514 cur = cur->next();
4515 }
4516 if (cur != Range::end()) {
4517 assert(cur->to() != cur->next()->from(), "ranges not separated");
4518
4519 if (mode == LIR_OpVisitState::outputMode) {
4520 return cur->from() <= op_id && op_id < cur->to();
4521 } else {
4522 return cur->from() <= op_id && op_id <= cur->to();
4523 }
4524 }
4525 return false;
4526 }
4527
4528 // returns true if the interval has any hole between hole_from and hole_to
4529 // (even if the hole has only the length 1)
4530 bool Interval::has_hole_between(int hole_from, int hole_to) {
4531 assert(hole_from < hole_to, "check");
4532 assert(from() <= hole_from && hole_to <= to(), "index out of interval");
4533
4534 Range* cur = _first;
4535 while (cur != Range::end()) {
4536 assert(cur->to() < cur->next()->from(), "no space between ranges");
4537
4538 // hole-range starts before this range -> hole
4539 if (hole_from < cur->from()) {
4540 return true;
4541
4542 // hole-range completely inside this range -> no hole
4543 } else if (hole_to <= cur->to()) {
4544 return false;
4545
4546 // overlapping of hole-range with this range -> hole
4547 } else if (hole_from <= cur->to()) {
4548 return true;
4549 }
4550
4551 cur = cur->next();
4552 }
4553
4554 return false;
4555 }
4556
4557
4558 #ifndef PRODUCT
4559 void Interval::print(outputStream* out) const {
4560 const char* SpillState2Name[] = { "no definition", "no spill store", "one spill store", "store at definition", "start in memory", "no optimization" };
4561 const char* UseKind2Name[] = { "N", "L", "S", "M" };
4562
4563 const char* type_name;
4564 LIR_Opr opr = LIR_OprFact::illegal();
4565 if (reg_num() < LIR_OprDesc::vreg_base) {
4566 type_name = "fixed";
4567 // need a temporary operand for fixed intervals because type() cannot be called
4568 #ifdef X86
4569 int last_xmm_reg = pd_last_xmm_reg;
4570 #ifdef _LP64
4571 if (UseAVX < 3) {
4572 last_xmm_reg = pd_first_xmm_reg + (pd_nof_xmm_regs_frame_map / 2) - 1;
4573 }
4574 #endif
4575 #endif
4576 if (assigned_reg() >= pd_first_cpu_reg && assigned_reg() <= pd_last_cpu_reg) {
4577 opr = LIR_OprFact::single_cpu(assigned_reg());
4578 } else if (assigned_reg() >= pd_first_fpu_reg && assigned_reg() <= pd_last_fpu_reg) {
4579 opr = LIR_OprFact::single_fpu(assigned_reg() - pd_first_fpu_reg);
4580 #ifdef X86
4581 } else if (assigned_reg() >= pd_first_xmm_reg && assigned_reg() <= last_xmm_reg) {
4582 opr = LIR_OprFact::single_xmm(assigned_reg() - pd_first_xmm_reg);
4583 #endif
4584 } else {
4585 ShouldNotReachHere();
4586 }
4587 } else {
4588 type_name = type2name(type());
4589 if (assigned_reg() != -1 &&
4590 (LinearScan::num_physical_regs(type()) == 1 || assigned_regHi() != -1)) {
4591 opr = LinearScan::calc_operand_for_interval(this);
4592 }
4593 }
4594
4595 out->print("%d %s ", reg_num(), type_name);
4596 if (opr->is_valid()) {
4597 out->print("\"");
4598 opr->print(out);
4599 out->print("\" ");
4600 }
4601 out->print("%d %d ", split_parent()->reg_num(), (register_hint(false) != NULL ? register_hint(false)->reg_num() : -1));
4602
4603 // print ranges
4604 Range* cur = _first;
4605 while (cur != Range::end()) {
4606 cur->print(out);
4607 cur = cur->next();
4608 assert(cur != NULL, "range list not closed with range sentinel");
4609 }
4610
4611 // print use positions
4612 int prev = 0;
4613 assert(_use_pos_and_kinds.length() % 2 == 0, "must be");
4614 for (int i =_use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
4615 assert(_use_pos_and_kinds.at(i + 1) >= firstValidKind && _use_pos_and_kinds.at(i + 1) <= lastValidKind, "invalid use kind");
4616 assert(prev < _use_pos_and_kinds.at(i), "use positions not sorted");
4617
4618 out->print("%d %s ", _use_pos_and_kinds.at(i), UseKind2Name[_use_pos_and_kinds.at(i + 1)]);
4619 prev = _use_pos_and_kinds.at(i);
4620 }
4621
4622 out->print(" \"%s\"", SpillState2Name[spill_state()]);
4623 out->cr();
4624 }
4625 #endif
4626
4627
4628
4629 // **** Implementation of IntervalWalker ****************************
4630
4631 IntervalWalker::IntervalWalker(LinearScan* allocator, Interval* unhandled_fixed_first, Interval* unhandled_any_first)
4632 : _compilation(allocator->compilation())
4633 , _allocator(allocator)
4634 {
4635 _unhandled_first[fixedKind] = unhandled_fixed_first;
4636 _unhandled_first[anyKind] = unhandled_any_first;
4637 _active_first[fixedKind] = Interval::end();
4638 _inactive_first[fixedKind] = Interval::end();
4639 _active_first[anyKind] = Interval::end();
4640 _inactive_first[anyKind] = Interval::end();
4641 _current_position = -1;
4642 _current = NULL;
4643 next_interval();
4644 }
4645
4646
4647 // append interval in order of current range from()
4648 void IntervalWalker::append_sorted(Interval** list, Interval* interval) {
4649 Interval* prev = NULL;
4650 Interval* cur = *list;
4651 while (cur->current_from() < interval->current_from()) {
4652 prev = cur; cur = cur->next();
4653 }
4654 if (prev == NULL) {
4655 *list = interval;
4656 } else {
4657 prev->set_next(interval);
4658 }
4659 interval->set_next(cur);
4660 }
4661
4662 void IntervalWalker::append_to_unhandled(Interval** list, Interval* interval) {
4663 assert(interval->from() >= current()->current_from(), "cannot append new interval before current walk position");
4664
4665 Interval* prev = NULL;
4666 Interval* cur = *list;
4667 while (cur->from() < interval->from() || (cur->from() == interval->from() && cur->first_usage(noUse) < interval->first_usage(noUse))) {
4668 prev = cur; cur = cur->next();
4669 }
4670 if (prev == NULL) {
4671 *list = interval;
4672 } else {
4673 prev->set_next(interval);
4674 }
4675 interval->set_next(cur);
4676 }
4677
4678
4679 inline bool IntervalWalker::remove_from_list(Interval** list, Interval* i) {
4680 while (*list != Interval::end() && *list != i) {
4681 list = (*list)->next_addr();
4682 }
4683 if (*list != Interval::end()) {
4684 assert(*list == i, "check");
4685 *list = (*list)->next();
4686 return true;
4687 } else {
4688 return false;
4689 }
4690 }
4691
4692 void IntervalWalker::remove_from_list(Interval* i) {
4693 bool deleted;
4694
4695 if (i->state() == activeState) {
4696 deleted = remove_from_list(active_first_addr(anyKind), i);
4697 } else {
4698 assert(i->state() == inactiveState, "invalid state");
4699 deleted = remove_from_list(inactive_first_addr(anyKind), i);
4700 }
4701
4702 assert(deleted, "interval has not been found in list");
4703 }
4704
4705
4706 void IntervalWalker::walk_to(IntervalState state, int from) {
4707 assert (state == activeState || state == inactiveState, "wrong state");
4708 for_each_interval_kind(kind) {
4709 Interval** prev = state == activeState ? active_first_addr(kind) : inactive_first_addr(kind);
4710 Interval* next = *prev;
4711 while (next->current_from() <= from) {
4712 Interval* cur = next;
4713 next = cur->next();
4714
4715 bool range_has_changed = false;
4716 while (cur->current_to() <= from) {
4717 cur->next_range();
4718 range_has_changed = true;
4719 }
4720
4721 // also handle move from inactive list to active list
4722 range_has_changed = range_has_changed || (state == inactiveState && cur->current_from() <= from);
4723
4724 if (range_has_changed) {
4725 // remove cur from list
4726 *prev = next;
4727 if (cur->current_at_end()) {
4728 // move to handled state (not maintained as a list)
4729 cur->set_state(handledState);
4730 interval_moved(cur, kind, state, handledState);
4731 } else if (cur->current_from() <= from){
4732 // sort into active list
4733 append_sorted(active_first_addr(kind), cur);
4734 cur->set_state(activeState);
4735 if (*prev == cur) {
4736 assert(state == activeState, "check");
4737 prev = cur->next_addr();
4738 }
4739 interval_moved(cur, kind, state, activeState);
4740 } else {
4741 // sort into inactive list
4742 append_sorted(inactive_first_addr(kind), cur);
4743 cur->set_state(inactiveState);
4744 if (*prev == cur) {
4745 assert(state == inactiveState, "check");
4746 prev = cur->next_addr();
4747 }
4748 interval_moved(cur, kind, state, inactiveState);
4749 }
4750 } else {
4751 prev = cur->next_addr();
4752 continue;
4753 }
4754 }
4755 }
4756 }
4757
4758
4759 void IntervalWalker::next_interval() {
4760 IntervalKind kind;
4761 Interval* any = _unhandled_first[anyKind];
4762 Interval* fixed = _unhandled_first[fixedKind];
4763
4764 if (any != Interval::end()) {
4765 // intervals may start at same position -> prefer fixed interval
4766 kind = fixed != Interval::end() && fixed->from() <= any->from() ? fixedKind : anyKind;
4767
4768 assert (kind == fixedKind && fixed->from() <= any->from() ||
4769 kind == anyKind && any->from() <= fixed->from(), "wrong interval!!!");
4770 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");
4771
4772 } else if (fixed != Interval::end()) {
4773 kind = fixedKind;
4774 } else {
4775 _current = NULL; return;
4776 }
4777 _current_kind = kind;
4778 _current = _unhandled_first[kind];
4779 _unhandled_first[kind] = _current->next();
4780 _current->set_next(Interval::end());
4781 _current->rewind_range();
4782 }
4783
4784
4785 void IntervalWalker::walk_to(int lir_op_id) {
4786 assert(_current_position <= lir_op_id, "can not walk backwards");
4787 while (current() != NULL) {
4788 bool is_active = current()->from() <= lir_op_id;
4789 int id = is_active ? current()->from() : lir_op_id;
4790
4791 TRACE_LINEAR_SCAN(2, if (_current_position < id) { tty->cr(); tty->print_cr("walk_to(%d) **************************************************************", id); })
4792
4793 // set _current_position prior to call of walk_to
4794 _current_position = id;
4795
4796 // call walk_to even if _current_position == id
4797 walk_to(activeState, id);
4798 walk_to(inactiveState, id);
4799
4800 if (is_active) {
4801 current()->set_state(activeState);
4802 if (activate_current()) {
4803 append_sorted(active_first_addr(current_kind()), current());
4804 interval_moved(current(), current_kind(), unhandledState, activeState);
4805 }
4806
4807 next_interval();
4808 } else {
4809 return;
4810 }
4811 }
4812 }
4813
4814 void IntervalWalker::interval_moved(Interval* interval, IntervalKind kind, IntervalState from, IntervalState to) {
4815 #ifndef PRODUCT
4816 if (TraceLinearScanLevel >= 4) {
4817 #define print_state(state) \
4818 switch(state) {\
4819 case unhandledState: tty->print("unhandled"); break;\
4820 case activeState: tty->print("active"); break;\
4821 case inactiveState: tty->print("inactive"); break;\
4822 case handledState: tty->print("handled"); break;\
4823 default: ShouldNotReachHere(); \
4824 }
4825
4826 print_state(from); tty->print(" to "); print_state(to);
4827 tty->fill_to(23);
4828 interval->print();
4829
4830 #undef print_state
4831 }
4832 #endif
4833 }
4834
4835
4836
4837 // **** Implementation of LinearScanWalker **************************
4838
4839 LinearScanWalker::LinearScanWalker(LinearScan* allocator, Interval* unhandled_fixed_first, Interval* unhandled_any_first)
4840 : IntervalWalker(allocator, unhandled_fixed_first, unhandled_any_first)
4841 , _move_resolver(allocator)
4842 {
4843 for (int i = 0; i < LinearScan::nof_regs; i++) {
4844 _spill_intervals[i] = new IntervalList(2);
4845 }
4846 }
4847
4848
4849 inline void LinearScanWalker::init_use_lists(bool only_process_use_pos) {
4850 for (int i = _first_reg; i <= _last_reg; i++) {
4851 _use_pos[i] = max_jint;
4852
4853 if (!only_process_use_pos) {
4854 _block_pos[i] = max_jint;
4855 _spill_intervals[i]->clear();
4856 }
4857 }
4858 }
4859
4860 inline void LinearScanWalker::exclude_from_use(int reg) {
4861 assert(reg < LinearScan::nof_regs, "interval must have a register assigned (stack slots not allowed)");
4862 if (reg >= _first_reg && reg <= _last_reg) {
4863 _use_pos[reg] = 0;
4864 }
4865 }
4866 inline void LinearScanWalker::exclude_from_use(Interval* i) {
4867 assert(i->assigned_reg() != any_reg, "interval has no register assigned");
4868
4869 exclude_from_use(i->assigned_reg());
4870 exclude_from_use(i->assigned_regHi());
4871 }
4872
4873 inline void LinearScanWalker::set_use_pos(int reg, Interval* i, int use_pos, bool only_process_use_pos) {
4874 assert(use_pos != 0, "must use exclude_from_use to set use_pos to 0");
4875
4876 if (reg >= _first_reg && reg <= _last_reg) {
4877 if (_use_pos[reg] > use_pos) {
4878 _use_pos[reg] = use_pos;
4879 }
4880 if (!only_process_use_pos) {
4881 _spill_intervals[reg]->append(i);
4882 }
4883 }
4884 }
4885 inline void LinearScanWalker::set_use_pos(Interval* i, int use_pos, bool only_process_use_pos) {
4886 assert(i->assigned_reg() != any_reg, "interval has no register assigned");
4887 if (use_pos != -1) {
4888 set_use_pos(i->assigned_reg(), i, use_pos, only_process_use_pos);
4889 set_use_pos(i->assigned_regHi(), i, use_pos, only_process_use_pos);
4890 }
4891 }
4892
4893 inline void LinearScanWalker::set_block_pos(int reg, Interval* i, int block_pos) {
4894 if (reg >= _first_reg && reg <= _last_reg) {
4895 if (_block_pos[reg] > block_pos) {
4896 _block_pos[reg] = block_pos;
4897 }
4898 if (_use_pos[reg] > block_pos) {
4899 _use_pos[reg] = block_pos;
4900 }
4901 }
4902 }
4903 inline void LinearScanWalker::set_block_pos(Interval* i, int block_pos) {
4904 assert(i->assigned_reg() != any_reg, "interval has no register assigned");
4905 if (block_pos != -1) {
4906 set_block_pos(i->assigned_reg(), i, block_pos);
4907 set_block_pos(i->assigned_regHi(), i, block_pos);
4908 }
4909 }
4910
4911
4912 void LinearScanWalker::free_exclude_active_fixed() {
4913 Interval* list = active_first(fixedKind);
4914 while (list != Interval::end()) {
4915 assert(list->assigned_reg() < LinearScan::nof_regs, "active interval must have a register assigned");
4916 exclude_from_use(list);
4917 list = list->next();
4918 }
4919 }
4920
4921 void LinearScanWalker::free_exclude_active_any() {
4922 Interval* list = active_first(anyKind);
4923 while (list != Interval::end()) {
4924 exclude_from_use(list);
4925 list = list->next();
4926 }
4927 }
4928
4929 void LinearScanWalker::free_collect_inactive_fixed(Interval* cur) {
4930 Interval* list = inactive_first(fixedKind);
4931 while (list != Interval::end()) {
4932 if (cur->to() <= list->current_from()) {
4933 assert(list->current_intersects_at(cur) == -1, "must not intersect");
4934 set_use_pos(list, list->current_from(), true);
4935 } else {
4936 set_use_pos(list, list->current_intersects_at(cur), true);
4937 }
4938 list = list->next();
4939 }
4940 }
4941
4942 void LinearScanWalker::free_collect_inactive_any(Interval* cur) {
4943 Interval* list = inactive_first(anyKind);
4944 while (list != Interval::end()) {
4945 set_use_pos(list, list->current_intersects_at(cur), true);
4946 list = list->next();
4947 }
4948 }
4949
4950 void LinearScanWalker::spill_exclude_active_fixed() {
4951 Interval* list = active_first(fixedKind);
4952 while (list != Interval::end()) {
4953 exclude_from_use(list);
4954 list = list->next();
4955 }
4956 }
4957
4958 void LinearScanWalker::spill_block_inactive_fixed(Interval* cur) {
4959 Interval* list = inactive_first(fixedKind);
4960 while (list != Interval::end()) {
4961 if (cur->to() > list->current_from()) {
4962 set_block_pos(list, list->current_intersects_at(cur));
4963 } else {
4964 assert(list->current_intersects_at(cur) == -1, "invalid optimization: intervals intersect");
4965 }
4966
4967 list = list->next();
4968 }
4969 }
4970
4971 void LinearScanWalker::spill_collect_active_any() {
4972 Interval* list = active_first(anyKind);
4973 while (list != Interval::end()) {
4974 set_use_pos(list, MIN2(list->next_usage(loopEndMarker, _current_position), list->to()), false);
4975 list = list->next();
4976 }
4977 }
4978
4979 void LinearScanWalker::spill_collect_inactive_any(Interval* cur) {
4980 Interval* list = inactive_first(anyKind);
4981 while (list != Interval::end()) {
4982 if (list->current_intersects(cur)) {
4983 set_use_pos(list, MIN2(list->next_usage(loopEndMarker, _current_position), list->to()), false);
4984 }
4985 list = list->next();
4986 }
4987 }
4988
4989
4990 void LinearScanWalker::insert_move(int op_id, Interval* src_it, Interval* dst_it) {
4991 // output all moves here. When source and target are equal, the move is
4992 // optimized away later in assign_reg_nums
4993
4994 op_id = (op_id + 1) & ~1;
4995 BlockBegin* op_block = allocator()->block_of_op_with_id(op_id);
4996 assert(op_id > 0 && allocator()->block_of_op_with_id(op_id - 2) == op_block, "cannot insert move at block boundary");
4997
4998 // calculate index of instruction inside instruction list of current block
4999 // the minimal index (for a block with no spill moves) can be calculated because the
5000 // numbering of instructions is known.
5001 // When the block already contains spill moves, the index must be increased until the
5002 // correct index is reached.
5003 LIR_OpList* list = op_block->lir()->instructions_list();
5004 int index = (op_id - list->at(0)->id()) / 2;
5005 assert(list->at(index)->id() <= op_id, "error in calculation");
5006
5007 while (list->at(index)->id() != op_id) {
5008 index++;
5009 assert(0 <= index && index < list->length(), "index out of bounds");
5010 }
5011 assert(1 <= index && index < list->length(), "index out of bounds");
5012 assert(list->at(index)->id() == op_id, "error in calculation");
5013
5014 // insert new instruction before instruction at position index
5015 _move_resolver.move_insert_position(op_block->lir(), index - 1);
5016 _move_resolver.add_mapping(src_it, dst_it);
5017 }
5018
5019
5020 int LinearScanWalker::find_optimal_split_pos(BlockBegin* min_block, BlockBegin* max_block, int max_split_pos) {
5021 int from_block_nr = min_block->linear_scan_number();
5022 int to_block_nr = max_block->linear_scan_number();
5023
5024 assert(0 <= from_block_nr && from_block_nr < block_count(), "out of range");
5025 assert(0 <= to_block_nr && to_block_nr < block_count(), "out of range");
5026 assert(from_block_nr < to_block_nr, "must cross block boundary");
5027
5028 // Try to split at end of max_block. If this would be after
5029 // max_split_pos, then use the begin of max_block
5030 int optimal_split_pos = max_block->last_lir_instruction_id() + 2;
5031 if (optimal_split_pos > max_split_pos) {
5032 optimal_split_pos = max_block->first_lir_instruction_id();
5033 }
5034
5035 int min_loop_depth = max_block->loop_depth();
5036 for (int i = to_block_nr - 1; i >= from_block_nr; i--) {
5037 BlockBegin* cur = block_at(i);
5038
5039 if (cur->loop_depth() < min_loop_depth) {
5040 // block with lower loop-depth found -> split at the end of this block
5041 min_loop_depth = cur->loop_depth();
5042 optimal_split_pos = cur->last_lir_instruction_id() + 2;
5043 }
5044 }
5045 assert(optimal_split_pos > allocator()->max_lir_op_id() || allocator()->is_block_begin(optimal_split_pos), "algorithm must move split pos to block boundary");
5046
5047 return optimal_split_pos;
5048 }
5049
5050
5051 int LinearScanWalker::find_optimal_split_pos(Interval* it, int min_split_pos, int max_split_pos, bool do_loop_optimization) {
5052 int optimal_split_pos = -1;
5053 if (min_split_pos == max_split_pos) {
5054 // trivial case, no optimization of split position possible
5055 TRACE_LINEAR_SCAN(4, tty->print_cr(" min-pos and max-pos are equal, no optimization possible"));
5056 optimal_split_pos = min_split_pos;
5057
5058 } else {
5059 assert(min_split_pos < max_split_pos, "must be true then");
5060 assert(min_split_pos > 0, "cannot access min_split_pos - 1 otherwise");
5061
5062 // reason for using min_split_pos - 1: when the minimal split pos is exactly at the
5063 // beginning of a block, then min_split_pos is also a possible split position.
5064 // Use the block before as min_block, because then min_block->last_lir_instruction_id() + 2 == min_split_pos
5065 BlockBegin* min_block = allocator()->block_of_op_with_id(min_split_pos - 1);
5066
5067 // reason for using max_split_pos - 1: otherwise there would be an assertion failure
5068 // when an interval ends at the end of the last block of the method
5069 // (in this case, max_split_pos == allocator()->max_lir_op_id() + 2, and there is no
5070 // block at this op_id)
5071 BlockBegin* max_block = allocator()->block_of_op_with_id(max_split_pos - 1);
5072
5073 assert(min_block->linear_scan_number() <= max_block->linear_scan_number(), "invalid order");
5074 if (min_block == max_block) {
5075 // split position cannot be moved to block boundary, so split as late as possible
5076 TRACE_LINEAR_SCAN(4, tty->print_cr(" cannot move split pos to block boundary because min_pos and max_pos are in same block"));
5077 optimal_split_pos = max_split_pos;
5078
5079 } else if (it->has_hole_between(max_split_pos - 1, max_split_pos) && !allocator()->is_block_begin(max_split_pos)) {
5080 // Do not move split position if the interval has a hole before max_split_pos.
5081 // Intervals resulting from Phi-Functions have more than one definition (marked
5082 // as mustHaveRegister) with a hole before each definition. When the register is needed
5083 // for the second definition, an earlier reloading is unnecessary.
5084 TRACE_LINEAR_SCAN(4, tty->print_cr(" interval has hole just before max_split_pos, so splitting at max_split_pos"));
5085 optimal_split_pos = max_split_pos;
5086
5087 } else {
5088 // seach optimal block boundary between min_split_pos and max_split_pos
5089 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()));
5090
5091 if (do_loop_optimization) {
5092 // Loop optimization: if a loop-end marker is found between min- and max-position,
5093 // then split before this loop
5094 int loop_end_pos = it->next_usage_exact(loopEndMarker, min_block->last_lir_instruction_id() + 2);
5095 TRACE_LINEAR_SCAN(4, tty->print_cr(" loop optimization: loop end found at pos %d", loop_end_pos));
5096
5097 assert(loop_end_pos > min_split_pos, "invalid order");
5098 if (loop_end_pos < max_split_pos) {
5099 // loop-end marker found between min- and max-position
5100 // if it is not the end marker for the same loop as the min-position, then move
5101 // the max-position to this loop block.
5102 // Desired result: uses tagged as shouldHaveRegister inside a loop cause a reloading
5103 // of the interval (normally, only mustHaveRegister causes a reloading)
5104 BlockBegin* loop_block = allocator()->block_of_op_with_id(loop_end_pos);
5105
5106 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()));
5107 assert(loop_block != min_block, "loop_block and min_block must be different because block boundary is needed between");
5108
5109 optimal_split_pos = find_optimal_split_pos(min_block, loop_block, loop_block->last_lir_instruction_id() + 2);
5110 if (optimal_split_pos == loop_block->last_lir_instruction_id() + 2) {
5111 optimal_split_pos = -1;
5112 TRACE_LINEAR_SCAN(4, tty->print_cr(" loop optimization not necessary"));
5113 } else {
5114 TRACE_LINEAR_SCAN(4, tty->print_cr(" loop optimization successful"));
5115 }
5116 }
5117 }
5118
5119 if (optimal_split_pos == -1) {
5120 // not calculated by loop optimization
5121 optimal_split_pos = find_optimal_split_pos(min_block, max_block, max_split_pos);
5122 }
5123 }
5124 }
5125 TRACE_LINEAR_SCAN(4, tty->print_cr(" optimal split position: %d", optimal_split_pos));
5126
5127 return optimal_split_pos;
5128 }
5129
5130
5131 /*
5132 split an interval at the optimal position between min_split_pos and
5133 max_split_pos in two parts:
5134 1) the left part has already a location assigned
5135 2) the right part is sorted into to the unhandled-list
5136 */
5137 void LinearScanWalker::split_before_usage(Interval* it, int min_split_pos, int max_split_pos) {
5138 TRACE_LINEAR_SCAN(2, tty->print ("----- splitting interval: "); it->print());
5139 TRACE_LINEAR_SCAN(2, tty->print_cr(" between %d and %d", min_split_pos, max_split_pos));
5140
5141 assert(it->from() < min_split_pos, "cannot split at start of interval");
5142 assert(current_position() < min_split_pos, "cannot split before current position");
5143 assert(min_split_pos <= max_split_pos, "invalid order");
5144 assert(max_split_pos <= it->to(), "cannot split after end of interval");
5145
5146 int optimal_split_pos = find_optimal_split_pos(it, min_split_pos, max_split_pos, true);
5147
5148 assert(min_split_pos <= optimal_split_pos && optimal_split_pos <= max_split_pos, "out of range");
5149 assert(optimal_split_pos <= it->to(), "cannot split after end of interval");
5150 assert(optimal_split_pos > it->from(), "cannot split at start of interval");
5151
5152 if (optimal_split_pos == it->to() && it->next_usage(mustHaveRegister, min_split_pos) == max_jint) {
5153 // the split position would be just before the end of the interval
5154 // -> no split at all necessary
5155 TRACE_LINEAR_SCAN(4, tty->print_cr(" no split necessary because optimal split position is at end of interval"));
5156 return;
5157 }
5158
5159 // must calculate this before the actual split is performed and before split position is moved to odd op_id
5160 bool move_necessary = !allocator()->is_block_begin(optimal_split_pos) && !it->has_hole_between(optimal_split_pos - 1, optimal_split_pos);
5161
5162 if (!allocator()->is_block_begin(optimal_split_pos)) {
5163 // move position before actual instruction (odd op_id)
5164 optimal_split_pos = (optimal_split_pos - 1) | 1;
5165 }
5166
5167 TRACE_LINEAR_SCAN(4, tty->print_cr(" splitting at position %d", optimal_split_pos));
5168 assert(allocator()->is_block_begin(optimal_split_pos) || (optimal_split_pos % 2 == 1), "split pos must be odd when not on block boundary");
5169 assert(!allocator()->is_block_begin(optimal_split_pos) || (optimal_split_pos % 2 == 0), "split pos must be even on block boundary");
5170
5171 Interval* split_part = it->split(optimal_split_pos);
5172
5173 allocator()->append_interval(split_part);
5174 allocator()->copy_register_flags(it, split_part);
5175 split_part->set_insert_move_when_activated(move_necessary);
5176 append_to_unhandled(unhandled_first_addr(anyKind), split_part);
5177
5178 TRACE_LINEAR_SCAN(2, tty->print_cr(" split interval in two parts (insert_move_when_activated: %d)", move_necessary));
5179 TRACE_LINEAR_SCAN(2, tty->print (" "); it->print());
5180 TRACE_LINEAR_SCAN(2, tty->print (" "); split_part->print());
5181 }
5182
5183 /*
5184 split an interval at the optimal position between min_split_pos and
5185 max_split_pos in two parts:
5186 1) the left part has already a location assigned
5187 2) the right part is always on the stack and therefore ignored in further processing
5188 */
5189 void LinearScanWalker::split_for_spilling(Interval* it) {
5190 // calculate allowed range of splitting position
5191 int max_split_pos = current_position();
5192 int min_split_pos = MAX2(it->previous_usage(shouldHaveRegister, max_split_pos) + 1, it->from());
5193
5194 TRACE_LINEAR_SCAN(2, tty->print ("----- splitting and spilling interval: "); it->print());
5195 TRACE_LINEAR_SCAN(2, tty->print_cr(" between %d and %d", min_split_pos, max_split_pos));
5196
5197 assert(it->state() == activeState, "why spill interval that is not active?");
5198 assert(it->from() <= min_split_pos, "cannot split before start of interval");
5199 assert(min_split_pos <= max_split_pos, "invalid order");
5200 assert(max_split_pos < it->to(), "cannot split at end end of interval");
5201 assert(current_position() < it->to(), "interval must not end before current position");
5202
5203 if (min_split_pos == it->from()) {
5204 // the whole interval is never used, so spill it entirely to memory
5205 TRACE_LINEAR_SCAN(2, tty->print_cr(" spilling entire interval because split pos is at beginning of interval"));
5206 assert(it->first_usage(shouldHaveRegister) > current_position(), "interval must not have use position before current_position");
5207
5208 allocator()->assign_spill_slot(it);
5209 allocator()->change_spill_state(it, min_split_pos);
5210
5211 // Also kick parent intervals out of register to memory when they have no use
5212 // position. This avoids short interval in register surrounded by intervals in
5213 // memory -> avoid useless moves from memory to register and back
5214 Interval* parent = it;
5215 while (parent != NULL && parent->is_split_child()) {
5216 parent = parent->split_child_before_op_id(parent->from());
5217
5218 if (parent->assigned_reg() < LinearScan::nof_regs) {
5219 if (parent->first_usage(shouldHaveRegister) == max_jint) {
5220 // parent is never used, so kick it out of its assigned register
5221 TRACE_LINEAR_SCAN(4, tty->print_cr(" kicking out interval %d out of its register because it is never used", parent->reg_num()));
5222 allocator()->assign_spill_slot(parent);
5223 } else {
5224 // do not go further back because the register is actually used by the interval
5225 parent = NULL;
5226 }
5227 }
5228 }
5229
5230 } else {
5231 // search optimal split pos, split interval and spill only the right hand part
5232 int optimal_split_pos = find_optimal_split_pos(it, min_split_pos, max_split_pos, false);
5233
5234 assert(min_split_pos <= optimal_split_pos && optimal_split_pos <= max_split_pos, "out of range");
5235 assert(optimal_split_pos < it->to(), "cannot split at end of interval");
5236 assert(optimal_split_pos >= it->from(), "cannot split before start of interval");
5237
5238 if (!allocator()->is_block_begin(optimal_split_pos)) {
5239 // move position before actual instruction (odd op_id)
5240 optimal_split_pos = (optimal_split_pos - 1) | 1;
5241 }
5242
5243 TRACE_LINEAR_SCAN(4, tty->print_cr(" splitting at position %d", optimal_split_pos));
5244 assert(allocator()->is_block_begin(optimal_split_pos) || (optimal_split_pos % 2 == 1), "split pos must be odd when not on block boundary");
5245 assert(!allocator()->is_block_begin(optimal_split_pos) || (optimal_split_pos % 2 == 0), "split pos must be even on block boundary");
5246
5247 Interval* spilled_part = it->split(optimal_split_pos);
5248 allocator()->append_interval(spilled_part);
5249 allocator()->assign_spill_slot(spilled_part);
5250 allocator()->change_spill_state(spilled_part, optimal_split_pos);
5251
5252 if (!allocator()->is_block_begin(optimal_split_pos)) {
5253 TRACE_LINEAR_SCAN(4, tty->print_cr(" inserting move from interval %d to %d", it->reg_num(), spilled_part->reg_num()));
5254 insert_move(optimal_split_pos, it, spilled_part);
5255 }
5256
5257 // the current_split_child is needed later when moves are inserted for reloading
5258 assert(spilled_part->current_split_child() == it, "overwriting wrong current_split_child");
5259 spilled_part->make_current_split_child();
5260
5261 TRACE_LINEAR_SCAN(2, tty->print_cr(" split interval in two parts"));
5262 TRACE_LINEAR_SCAN(2, tty->print (" "); it->print());
5263 TRACE_LINEAR_SCAN(2, tty->print (" "); spilled_part->print());
5264 }
5265 }
5266
5267
5268 void LinearScanWalker::split_stack_interval(Interval* it) {
5269 int min_split_pos = current_position() + 1;
5270 int max_split_pos = MIN2(it->first_usage(shouldHaveRegister), it->to());
5271
5272 split_before_usage(it, min_split_pos, max_split_pos);
5273 }
5274
5275 void LinearScanWalker::split_when_partial_register_available(Interval* it, int register_available_until) {
5276 int min_split_pos = MAX2(it->previous_usage(shouldHaveRegister, register_available_until), it->from() + 1);
5277 int max_split_pos = register_available_until;
5278
5279 split_before_usage(it, min_split_pos, max_split_pos);
5280 }
5281
5282 void LinearScanWalker::split_and_spill_interval(Interval* it) {
5283 assert(it->state() == activeState || it->state() == inactiveState, "other states not allowed");
5284
5285 int current_pos = current_position();
5286 if (it->state() == inactiveState) {
5287 // the interval is currently inactive, so no spill slot is needed for now.
5288 // when the split part is activated, the interval has a new chance to get a register,
5289 // so in the best case no stack slot is necessary
5290 assert(it->has_hole_between(current_pos - 1, current_pos + 1), "interval can not be inactive otherwise");
5291 split_before_usage(it, current_pos + 1, current_pos + 1);
5292
5293 } else {
5294 // search the position where the interval must have a register and split
5295 // at the optimal position before.
5296 // The new created part is added to the unhandled list and will get a register
5297 // when it is activated
5298 int min_split_pos = current_pos + 1;
5299 int max_split_pos = MIN2(it->next_usage(mustHaveRegister, min_split_pos), it->to());
5300
5301 split_before_usage(it, min_split_pos, max_split_pos);
5302
5303 assert(it->next_usage(mustHaveRegister, current_pos) == max_jint, "the remaining part is spilled to stack and therefore has no register");
5304 split_for_spilling(it);
5305 }
5306 }
5307
5308
5309 int LinearScanWalker::find_free_reg(int reg_needed_until, int interval_to, int hint_reg, int ignore_reg, bool* need_split) {
5310 int min_full_reg = any_reg;
5311 int max_partial_reg = any_reg;
5312
5313 for (int i = _first_reg; i <= _last_reg; i++) {
5314 if (i == ignore_reg) {
5315 // this register must be ignored
5316
5317 } else if (_use_pos[i] >= interval_to) {
5318 // this register is free for the full interval
5319 if (min_full_reg == any_reg || i == hint_reg || (_use_pos[i] < _use_pos[min_full_reg] && min_full_reg != hint_reg)) {
5320 min_full_reg = i;
5321 }
5322 } else if (_use_pos[i] > reg_needed_until) {
5323 // this register is at least free until reg_needed_until
5324 if (max_partial_reg == any_reg || i == hint_reg || (_use_pos[i] > _use_pos[max_partial_reg] && max_partial_reg != hint_reg)) {
5325 max_partial_reg = i;
5326 }
5327 }
5328 }
5329
5330 if (min_full_reg != any_reg) {
5331 return min_full_reg;
5332 } else if (max_partial_reg != any_reg) {
5333 *need_split = true;
5334 return max_partial_reg;
5335 } else {
5336 return any_reg;
5337 }
5338 }
5339
5340 int LinearScanWalker::find_free_double_reg(int reg_needed_until, int interval_to, int hint_reg, bool* need_split) {
5341 assert((_last_reg - _first_reg + 1) % 2 == 0, "adjust algorithm");
5342
5343 int min_full_reg = any_reg;
5344 int max_partial_reg = any_reg;
5345
5346 for (int i = _first_reg; i < _last_reg; i+=2) {
5347 if (_use_pos[i] >= interval_to && _use_pos[i + 1] >= interval_to) {
5348 // this register is free for the full interval
5349 if (min_full_reg == any_reg || i == hint_reg || (_use_pos[i] < _use_pos[min_full_reg] && min_full_reg != hint_reg)) {
5350 min_full_reg = i;
5351 }
5352 } else if (_use_pos[i] > reg_needed_until && _use_pos[i + 1] > reg_needed_until) {
5353 // this register is at least free until reg_needed_until
5354 if (max_partial_reg == any_reg || i == hint_reg || (_use_pos[i] > _use_pos[max_partial_reg] && max_partial_reg != hint_reg)) {
5355 max_partial_reg = i;
5356 }
5357 }
5358 }
5359
5360 if (min_full_reg != any_reg) {
5361 return min_full_reg;
5362 } else if (max_partial_reg != any_reg) {
5363 *need_split = true;
5364 return max_partial_reg;
5365 } else {
5366 return any_reg;
5367 }
5368 }
5369
5370
5371 bool LinearScanWalker::alloc_free_reg(Interval* cur) {
5372 TRACE_LINEAR_SCAN(2, tty->print("trying to find free register for "); cur->print());
5373
5374 init_use_lists(true);
5375 free_exclude_active_fixed();
5376 free_exclude_active_any();
5377 free_collect_inactive_fixed(cur);
5378 free_collect_inactive_any(cur);
5379 assert(unhandled_first(fixedKind) == Interval::end(), "must not have unhandled fixed intervals because all fixed intervals have a use at position 0");
5380
5381 // _use_pos contains the start of the next interval that has this register assigned
5382 // (either as a fixed register or a normal allocated register in the past)
5383 // only intervals overlapping with cur are processed, non-overlapping invervals can be ignored safely
5384 TRACE_LINEAR_SCAN(4, tty->print_cr(" state of registers:"));
5385 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]));
5386
5387 int hint_reg, hint_regHi;
5388 Interval* register_hint = cur->register_hint();
5389 if (register_hint != NULL) {
5390 hint_reg = register_hint->assigned_reg();
5391 hint_regHi = register_hint->assigned_regHi();
5392
5393 if (allocator()->is_precolored_cpu_interval(register_hint)) {
5394 assert(hint_reg != any_reg && hint_regHi == any_reg, "must be for fixed intervals");
5395 hint_regHi = hint_reg + 1; // connect e.g. eax-edx
5396 }
5397 TRACE_LINEAR_SCAN(4, tty->print(" hint registers %d, %d from interval ", hint_reg, hint_regHi); register_hint->print());
5398
5399 } else {
5400 hint_reg = any_reg;
5401 hint_regHi = any_reg;
5402 }
5403 assert(hint_reg == any_reg || hint_reg != hint_regHi, "hint reg and regHi equal");
5404 assert(cur->assigned_reg() == any_reg && cur->assigned_regHi() == any_reg, "register already assigned to interval");
5405
5406 // the register must be free at least until this position
5407 int reg_needed_until = cur->from() + 1;
5408 int interval_to = cur->to();
5409
5410 bool need_split = false;
5411 int split_pos;
5412 int reg;
5413 int regHi = any_reg;
5414
5415 if (_adjacent_regs) {
5416 reg = find_free_double_reg(reg_needed_until, interval_to, hint_reg, &need_split);
5417 regHi = reg + 1;
5418 if (reg == any_reg) {
5419 return false;
5420 }
5421 split_pos = MIN2(_use_pos[reg], _use_pos[regHi]);
5422
5423 } else {
5424 reg = find_free_reg(reg_needed_until, interval_to, hint_reg, any_reg, &need_split);
5425 if (reg == any_reg) {
5426 return false;
5427 }
5428 split_pos = _use_pos[reg];
5429
5430 if (_num_phys_regs == 2) {
5431 regHi = find_free_reg(reg_needed_until, interval_to, hint_regHi, reg, &need_split);
5432
5433 if (_use_pos[reg] < interval_to && regHi == any_reg) {
5434 // do not split interval if only one register can be assigned until the split pos
5435 // (when one register is found for the whole interval, split&spill is only
5436 // performed for the hi register)
5437 return false;
5438
5439 } else if (regHi != any_reg) {
5440 split_pos = MIN2(split_pos, _use_pos[regHi]);
5441
5442 // sort register numbers to prevent e.g. a move from eax,ebx to ebx,eax
5443 if (reg > regHi) {
5444 int temp = reg;
5445 reg = regHi;
5446 regHi = temp;
5447 }
5448 }
5449 }
5450 }
5451
5452 cur->assign_reg(reg, regHi);
5453 TRACE_LINEAR_SCAN(2, tty->print_cr("selected register %d, %d", reg, regHi));
5454
5455 assert(split_pos > 0, "invalid split_pos");
5456 if (need_split) {
5457 // register not available for full interval, so split it
5458 split_when_partial_register_available(cur, split_pos);
5459 }
5460
5461 // only return true if interval is completely assigned
5462 return _num_phys_regs == 1 || regHi != any_reg;
5463 }
5464
5465
5466 int LinearScanWalker::find_locked_reg(int reg_needed_until, int interval_to, int ignore_reg, bool* need_split) {
5467 int max_reg = any_reg;
5468
5469 for (int i = _first_reg; i <= _last_reg; i++) {
5470 if (i == ignore_reg) {
5471 // this register must be ignored
5472
5473 } else if (_use_pos[i] > reg_needed_until) {
5474 if (max_reg == any_reg || _use_pos[i] > _use_pos[max_reg]) {
5475 max_reg = i;
5476 }
5477 }
5478 }
5479
5480 if (max_reg != any_reg && _block_pos[max_reg] <= interval_to) {
5481 *need_split = true;
5482 }
5483
5484 return max_reg;
5485 }
5486
5487 int LinearScanWalker::find_locked_double_reg(int reg_needed_until, int interval_to, bool* need_split) {
5488 assert((_last_reg - _first_reg + 1) % 2 == 0, "adjust algorithm");
5489
5490 int max_reg = any_reg;
5491
5492 for (int i = _first_reg; i < _last_reg; i+=2) {
5493 if (_use_pos[i] > reg_needed_until && _use_pos[i + 1] > reg_needed_until) {
5494 if (max_reg == any_reg || _use_pos[i] > _use_pos[max_reg]) {
5495 max_reg = i;
5496 }
5497 }
5498 }
5499
5500 if (max_reg != any_reg &&
5501 (_block_pos[max_reg] <= interval_to || _block_pos[max_reg + 1] <= interval_to)) {
5502 *need_split = true;
5503 }
5504
5505 return max_reg;
5506 }
5507
5508 void LinearScanWalker::split_and_spill_intersecting_intervals(int reg, int regHi) {
5509 assert(reg != any_reg, "no register assigned");
5510
5511 for (int i = 0; i < _spill_intervals[reg]->length(); i++) {
5512 Interval* it = _spill_intervals[reg]->at(i);
5513 remove_from_list(it);
5514 split_and_spill_interval(it);
5515 }
5516
5517 if (regHi != any_reg) {
5518 IntervalList* processed = _spill_intervals[reg];
5519 for (int i = 0; i < _spill_intervals[regHi]->length(); i++) {
5520 Interval* it = _spill_intervals[regHi]->at(i);
5521 if (processed->find(it) == -1) {
5522 remove_from_list(it);
5523 split_and_spill_interval(it);
5524 }
5525 }
5526 }
5527 }
5528
5529
5530 // Split an Interval and spill it to memory so that cur can be placed in a register
5531 void LinearScanWalker::alloc_locked_reg(Interval* cur) {
5532 TRACE_LINEAR_SCAN(2, tty->print("need to split and spill to get register for "); cur->print());
5533
5534 // collect current usage of registers
5535 init_use_lists(false);
5536 spill_exclude_active_fixed();
5537 assert(unhandled_first(fixedKind) == Interval::end(), "must not have unhandled fixed intervals because all fixed intervals have a use at position 0");
5538 spill_block_inactive_fixed(cur);
5539 spill_collect_active_any();
5540 spill_collect_inactive_any(cur);
5541
5542 #ifndef PRODUCT
5543 if (TraceLinearScanLevel >= 4) {
5544 tty->print_cr(" state of registers:");
5545 for (int i = _first_reg; i <= _last_reg; i++) {
5546 tty->print(" reg %d: use_pos: %d, block_pos: %d, intervals: ", i, _use_pos[i], _block_pos[i]);
5547 for (int j = 0; j < _spill_intervals[i]->length(); j++) {
5548 tty->print("%d ", _spill_intervals[i]->at(j)->reg_num());
5549 }
5550 tty->cr();
5551 }
5552 }
5553 #endif
5554
5555 // the register must be free at least until this position
5556 int reg_needed_until = MIN2(cur->first_usage(mustHaveRegister), cur->from() + 1);
5557 int interval_to = cur->to();
5558 assert (reg_needed_until > 0 && reg_needed_until < max_jint, "interval has no use");
5559
5560 int split_pos = 0;
5561 int use_pos = 0;
5562 bool need_split = false;
5563 int reg, regHi;
5564
5565 if (_adjacent_regs) {
5566 reg = find_locked_double_reg(reg_needed_until, interval_to, &need_split);
5567 regHi = reg + 1;
5568
5569 if (reg != any_reg) {
5570 use_pos = MIN2(_use_pos[reg], _use_pos[regHi]);
5571 split_pos = MIN2(_block_pos[reg], _block_pos[regHi]);
5572 }
5573 } else {
5574 reg = find_locked_reg(reg_needed_until, interval_to, cur->assigned_reg(), &need_split);
5575 regHi = any_reg;
5576
5577 if (reg != any_reg) {
5578 use_pos = _use_pos[reg];
5579 split_pos = _block_pos[reg];
5580
5581 if (_num_phys_regs == 2) {
5582 if (cur->assigned_reg() != any_reg) {
5583 regHi = reg;
5584 reg = cur->assigned_reg();
5585 } else {
5586 regHi = find_locked_reg(reg_needed_until, interval_to, reg, &need_split);
5587 if (regHi != any_reg) {
5588 use_pos = MIN2(use_pos, _use_pos[regHi]);
5589 split_pos = MIN2(split_pos, _block_pos[regHi]);
5590 }
5591 }
5592
5593 if (regHi != any_reg && reg > regHi) {
5594 // sort register numbers to prevent e.g. a move from eax,ebx to ebx,eax
5595 int temp = reg;
5596 reg = regHi;
5597 regHi = temp;
5598 }
5599 }
5600 }
5601 }
5602
5603 if (reg == any_reg || (_num_phys_regs == 2 && regHi == any_reg) || use_pos <= cur->first_usage(mustHaveRegister)) {
5604 // the first use of cur is later than the spilling position -> spill cur
5605 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));
5606
5607 if (cur->first_usage(mustHaveRegister) <= cur->from() + 1) {
5608 assert(false, "cannot spill interval that is used in first instruction (possible reason: no register found)");
5609 // assign a reasonable register and do a bailout in product mode to avoid errors
5610 allocator()->assign_spill_slot(cur);
5611 BAILOUT("LinearScan: no register found");
5612 }
5613
5614 split_and_spill_interval(cur);
5615 } else {
5616 TRACE_LINEAR_SCAN(4, tty->print_cr("decided to use register %d, %d", reg, regHi));
5617 assert(reg != any_reg && (_num_phys_regs == 1 || regHi != any_reg), "no register found");
5618 assert(split_pos > 0, "invalid split_pos");
5619 assert(need_split == false || split_pos > cur->from(), "splitting interval at from");
5620
5621 cur->assign_reg(reg, regHi);
5622 if (need_split) {
5623 // register not available for full interval, so split it
5624 split_when_partial_register_available(cur, split_pos);
5625 }
5626
5627 // perform splitting and spilling for all affected intervalls
5628 split_and_spill_intersecting_intervals(reg, regHi);
5629 }
5630 }
5631
5632 bool LinearScanWalker::no_allocation_possible(Interval* cur) {
5633 #ifdef X86
5634 // fast calculation of intervals that can never get a register because the
5635 // the next instruction is a call that blocks all registers
5636 // Note: this does not work if callee-saved registers are available (e.g. on Sparc)
5637
5638 // check if this interval is the result of a split operation
5639 // (an interval got a register until this position)
5640 int pos = cur->from();
5641 if ((pos & 1) == 1) {
5642 // the current instruction is a call that blocks all registers
5643 if (pos < allocator()->max_lir_op_id() && allocator()->has_call(pos + 1)) {
5644 TRACE_LINEAR_SCAN(4, tty->print_cr(" free register cannot be available because all registers blocked by following call"));
5645
5646 // safety check that there is really no register available
5647 assert(alloc_free_reg(cur) == false, "found a register for this interval");
5648 return true;
5649 }
5650
5651 }
5652 #endif
5653 return false;
5654 }
5655
5656 void LinearScanWalker::init_vars_for_alloc(Interval* cur) {
5657 BasicType type = cur->type();
5658 _num_phys_regs = LinearScan::num_physical_regs(type);
5659 _adjacent_regs = LinearScan::requires_adjacent_regs(type);
5660
5661 if (pd_init_regs_for_alloc(cur)) {
5662 // the appropriate register range was selected.
5663 } else if (type == T_FLOAT || type == T_DOUBLE) {
5664 _first_reg = pd_first_fpu_reg;
5665 _last_reg = pd_last_fpu_reg;
5666 } else {
5667 _first_reg = pd_first_cpu_reg;
5668 _last_reg = FrameMap::last_cpu_reg();
5669 }
5670
5671 assert(0 <= _first_reg && _first_reg < LinearScan::nof_regs, "out of range");
5672 assert(0 <= _last_reg && _last_reg < LinearScan::nof_regs, "out of range");
5673 }
5674
5675
5676 bool LinearScanWalker::is_move(LIR_Op* op, Interval* from, Interval* to) {
5677 if (op->code() != lir_move) {
5678 return false;
5679 }
5680 assert(op->as_Op1() != NULL, "move must be LIR_Op1");
5681
5682 LIR_Opr in = ((LIR_Op1*)op)->in_opr();
5683 LIR_Opr res = ((LIR_Op1*)op)->result_opr();
5684 return in->is_virtual() && res->is_virtual() && in->vreg_number() == from->reg_num() && res->vreg_number() == to->reg_num();
5685 }
5686
5687 // optimization (especially for phi functions of nested loops):
5688 // assign same spill slot to non-intersecting intervals
5689 void LinearScanWalker::combine_spilled_intervals(Interval* cur) {
5690 if (cur->is_split_child()) {
5691 // optimization is only suitable for split parents
5692 return;
5693 }
5694
5695 Interval* register_hint = cur->register_hint(false);
5696 if (register_hint == NULL) {
5697 // cur is not the target of a move, otherwise register_hint would be set
5698 return;
5699 }
5700 assert(register_hint->is_split_parent(), "register hint must be split parent");
5701
5702 if (cur->spill_state() != noOptimization || register_hint->spill_state() != noOptimization) {
5703 // combining the stack slots for intervals where spill move optimization is applied
5704 // is not benefitial and would cause problems
5705 return;
5706 }
5707
5708 int begin_pos = cur->from();
5709 int end_pos = cur->to();
5710 if (end_pos > allocator()->max_lir_op_id() || (begin_pos & 1) != 0 || (end_pos & 1) != 0) {
5711 // safety check that lir_op_with_id is allowed
5712 return;
5713 }
5714
5715 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)) {
5716 // cur and register_hint are not connected with two moves
5717 return;
5718 }
5719
5720 Interval* begin_hint = register_hint->split_child_at_op_id(begin_pos, LIR_OpVisitState::inputMode);
5721 Interval* end_hint = register_hint->split_child_at_op_id(end_pos, LIR_OpVisitState::outputMode);
5722 if (begin_hint == end_hint || begin_hint->to() != begin_pos || end_hint->from() != end_pos) {
5723 // register_hint must be split, otherwise the re-writing of use positions does not work
5724 return;
5725 }
5726
5727 assert(begin_hint->assigned_reg() != any_reg, "must have register assigned");
5728 assert(end_hint->assigned_reg() == any_reg, "must not have register assigned");
5729 assert(cur->first_usage(mustHaveRegister) == begin_pos, "must have use position at begin of interval because of move");
5730 assert(end_hint->first_usage(mustHaveRegister) == end_pos, "must have use position at begin of interval because of move");
5731
5732 if (begin_hint->assigned_reg() < LinearScan::nof_regs) {
5733 // register_hint is not spilled at begin_pos, so it would not be benefitial to immediately spill cur
5734 return;
5735 }
5736 assert(register_hint->canonical_spill_slot() != -1, "must be set when part of interval was spilled");
5737
5738 // modify intervals such that cur gets the same stack slot as register_hint
5739 // delete use positions to prevent the intervals to get a register at beginning
5740 cur->set_canonical_spill_slot(register_hint->canonical_spill_slot());
5741 cur->remove_first_use_pos();
5742 end_hint->remove_first_use_pos();
5743 }
5744
5745
5746 // allocate a physical register or memory location to an interval
5747 bool LinearScanWalker::activate_current() {
5748 Interval* cur = current();
5749 bool result = true;
5750
5751 TRACE_LINEAR_SCAN(2, tty->print ("+++++ activating interval "); cur->print());
5752 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()));
5753
5754 if (cur->assigned_reg() >= LinearScan::nof_regs) {
5755 // activating an interval that has a stack slot assigned -> split it at first use position
5756 // used for method parameters
5757 TRACE_LINEAR_SCAN(4, tty->print_cr(" interval has spill slot assigned (method parameter) -> split it before first use"));
5758
5759 split_stack_interval(cur);
5760 result = false;
5761
5762 } else if (allocator()->gen()->is_vreg_flag_set(cur->reg_num(), LIRGenerator::must_start_in_memory)) {
5763 // activating an interval that must start in a stack slot, but may get a register later
5764 // used for lir_roundfp: rounding is done by store to stack and reload later
5765 TRACE_LINEAR_SCAN(4, tty->print_cr(" interval must start in stack slot -> split it before first use"));
5766 assert(cur->assigned_reg() == any_reg && cur->assigned_regHi() == any_reg, "register already assigned");
5767
5768 allocator()->assign_spill_slot(cur);
5769 split_stack_interval(cur);
5770 result = false;
5771
5772 } else if (cur->assigned_reg() == any_reg) {
5773 // interval has not assigned register -> normal allocation
5774 // (this is the normal case for most intervals)
5775 TRACE_LINEAR_SCAN(4, tty->print_cr(" normal allocation of register"));
5776
5777 // assign same spill slot to non-intersecting intervals
5778 combine_spilled_intervals(cur);
5779
5780 init_vars_for_alloc(cur);
5781 if (no_allocation_possible(cur) || !alloc_free_reg(cur)) {
5782 // no empty register available.
5783 // split and spill another interval so that this interval gets a register
5784 alloc_locked_reg(cur);
5785 }
5786
5787 // spilled intervals need not be move to active-list
5788 if (cur->assigned_reg() >= LinearScan::nof_regs) {
5789 result = false;
5790 }
5791 }
5792
5793 // load spilled values that become active from stack slot to register
5794 if (cur->insert_move_when_activated()) {
5795 assert(cur->is_split_child(), "must be");
5796 assert(cur->current_split_child() != NULL, "must be");
5797 assert(cur->current_split_child()->reg_num() != cur->reg_num(), "cannot insert move between same interval");
5798 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()));
5799
5800 insert_move(cur->from(), cur->current_split_child(), cur);
5801 }
5802 cur->make_current_split_child();
5803
5804 return result; // true = interval is moved to active list
5805 }
5806
5807
5808 // Implementation of EdgeMoveOptimizer
5809
5810 EdgeMoveOptimizer::EdgeMoveOptimizer() :
5811 _edge_instructions(4),
5812 _edge_instructions_idx(4)
5813 {
5814 }
5815
5816 void EdgeMoveOptimizer::optimize(BlockList* code) {
5817 EdgeMoveOptimizer optimizer = EdgeMoveOptimizer();
5818
5819 // ignore the first block in the list (index 0 is not processed)
5820 for (int i = code->length() - 1; i >= 1; i--) {
5821 BlockBegin* block = code->at(i);
5822
5823 if (block->number_of_preds() > 1 && !block->is_set(BlockBegin::exception_entry_flag)) {
5824 optimizer.optimize_moves_at_block_end(block);
5825 }
5826 if (block->number_of_sux() == 2) {
5827 optimizer.optimize_moves_at_block_begin(block);
5828 }
5829 }
5830 }
5831
5832
5833 // clear all internal data structures
5834 void EdgeMoveOptimizer::init_instructions() {
5835 _edge_instructions.clear();
5836 _edge_instructions_idx.clear();
5837 }
5838
5839 // append a lir-instruction-list and the index of the current operation in to the list
5840 void EdgeMoveOptimizer::append_instructions(LIR_OpList* instructions, int instructions_idx) {
5841 _edge_instructions.append(instructions);
5842 _edge_instructions_idx.append(instructions_idx);
5843 }
5844
5845 // return the current operation of the given edge (predecessor or successor)
5846 LIR_Op* EdgeMoveOptimizer::instruction_at(int edge) {
5847 LIR_OpList* instructions = _edge_instructions.at(edge);
5848 int idx = _edge_instructions_idx.at(edge);
5849
5850 if (idx < instructions->length()) {
5851 return instructions->at(idx);
5852 } else {
5853 return NULL;
5854 }
5855 }
5856
5857 // removes the current operation of the given edge (predecessor or successor)
5858 void EdgeMoveOptimizer::remove_cur_instruction(int edge, bool decrement_index) {
5859 LIR_OpList* instructions = _edge_instructions.at(edge);
5860 int idx = _edge_instructions_idx.at(edge);
5861 instructions->remove_at(idx);
5862
5863 if (decrement_index) {
5864 _edge_instructions_idx.at_put(edge, idx - 1);
5865 }
5866 }
5867
5868
5869 bool EdgeMoveOptimizer::operations_different(LIR_Op* op1, LIR_Op* op2) {
5870 if (op1 == NULL || op2 == NULL) {
5871 // at least one block is already empty -> no optimization possible
5872 return true;
5873 }
5874
5875 if (op1->code() == lir_move && op2->code() == lir_move) {
5876 assert(op1->as_Op1() != NULL, "move must be LIR_Op1");
5877 assert(op2->as_Op1() != NULL, "move must be LIR_Op1");
5878 LIR_Op1* move1 = (LIR_Op1*)op1;
5879 LIR_Op1* move2 = (LIR_Op1*)op2;
5880 if (move1->info() == move2->info() && move1->in_opr() == move2->in_opr() && move1->result_opr() == move2->result_opr()) {
5881 // these moves are exactly equal and can be optimized
5882 return false;
5883 }
5884
5885 } else if (op1->code() == lir_fxch && op2->code() == lir_fxch) {
5886 assert(op1->as_Op1() != NULL, "fxch must be LIR_Op1");
5887 assert(op2->as_Op1() != NULL, "fxch must be LIR_Op1");
5888 LIR_Op1* fxch1 = (LIR_Op1*)op1;
5889 LIR_Op1* fxch2 = (LIR_Op1*)op2;
5890 if (fxch1->in_opr()->as_jint() == fxch2->in_opr()->as_jint()) {
5891 // equal FPU stack operations can be optimized
5892 return false;
5893 }
5894
5895 } else if (op1->code() == lir_fpop_raw && op2->code() == lir_fpop_raw) {
5896 // equal FPU stack operations can be optimized
5897 return false;
5898 }
5899
5900 // no optimization possible
5901 return true;
5902 }
5903
5904 void EdgeMoveOptimizer::optimize_moves_at_block_end(BlockBegin* block) {
5905 TRACE_LINEAR_SCAN(4, tty->print_cr("optimizing moves at end of block B%d", block->block_id()));
5906
5907 if (block->is_predecessor(block)) {
5908 // currently we can't handle this correctly.
5909 return;
5910 }
5911
5912 init_instructions();
5913 int num_preds = block->number_of_preds();
5914 assert(num_preds > 1, "do not call otherwise");
5915 assert(!block->is_set(BlockBegin::exception_entry_flag), "exception handlers not allowed");
5916
5917 // setup a list with the lir-instructions of all predecessors
5918 int i;
5919 for (i = 0; i < num_preds; i++) {
5920 BlockBegin* pred = block->pred_at(i);
5921 LIR_OpList* pred_instructions = pred->lir()->instructions_list();
5922
5923 if (pred->number_of_sux() != 1) {
5924 // this can happen with switch-statements where multiple edges are between
5925 // the same blocks.
5926 return;
5927 }
5928
5929 assert(pred->number_of_sux() == 1, "can handle only one successor");
5930 assert(pred->sux_at(0) == block, "invalid control flow");
5931 assert(pred_instructions->last()->code() == lir_branch, "block with successor must end with branch");
5932 assert(pred_instructions->last()->as_OpBranch() != NULL, "branch must be LIR_OpBranch");
5933 assert(pred_instructions->last()->as_OpBranch()->cond() == lir_cond_always, "block must end with unconditional branch");
5934
5935 if (pred_instructions->last()->info() != NULL) {
5936 // can not optimize instructions when debug info is needed
5937 return;
5938 }
5939
5940 // ignore the unconditional branch at the end of the block
5941 append_instructions(pred_instructions, pred_instructions->length() - 2);
5942 }
5943
5944
5945 // process lir-instructions while all predecessors end with the same instruction
5946 while (true) {
5947 LIR_Op* op = instruction_at(0);
5948 for (i = 1; i < num_preds; i++) {
5949 if (operations_different(op, instruction_at(i))) {
5950 // these instructions are different and cannot be optimized ->
5951 // no further optimization possible
5952 return;
5953 }
5954 }
5955
5956 TRACE_LINEAR_SCAN(4, tty->print("found instruction that is equal in all %d predecessors: ", num_preds); op->print());
5957
5958 // insert the instruction at the beginning of the current block
5959 block->lir()->insert_before(1, op);
5960
5961 // delete the instruction at the end of all predecessors
5962 for (i = 0; i < num_preds; i++) {
5963 remove_cur_instruction(i, true);
5964 }
5965 }
5966 }
5967
5968
5969 void EdgeMoveOptimizer::optimize_moves_at_block_begin(BlockBegin* block) {
5970 TRACE_LINEAR_SCAN(4, tty->print_cr("optimization moves at begin of block B%d", block->block_id()));
5971
5972 init_instructions();
5973 int num_sux = block->number_of_sux();
5974
5975 LIR_OpList* cur_instructions = block->lir()->instructions_list();
5976
5977 assert(num_sux == 2, "method should not be called otherwise");
5978 assert(cur_instructions->last()->code() == lir_branch, "block with successor must end with branch");
5979 assert(cur_instructions->last()->as_OpBranch() != NULL, "branch must be LIR_OpBranch");
5980 assert(cur_instructions->last()->as_OpBranch()->cond() == lir_cond_always, "block must end with unconditional branch");
5981
5982 if (cur_instructions->last()->info() != NULL) {
5983 // can no optimize instructions when debug info is needed
5984 return;
5985 }
5986
5987 LIR_Op* branch = cur_instructions->at(cur_instructions->length() - 2);
5988 if (branch->info() != NULL || (branch->code() != lir_branch && branch->code() != lir_cond_float_branch)) {
5989 // not a valid case for optimization
5990 // currently, only blocks that end with two branches (conditional branch followed
5991 // by unconditional branch) are optimized
5992 return;
5993 }
5994
5995 // now it is guaranteed that the block ends with two branch instructions.
5996 // the instructions are inserted at the end of the block before these two branches
5997 int insert_idx = cur_instructions->length() - 2;
5998
5999 int i;
6000 #ifdef ASSERT
6001 for (i = insert_idx - 1; i >= 0; i--) {
6002 LIR_Op* op = cur_instructions->at(i);
6003 if ((op->code() == lir_branch || op->code() == lir_cond_float_branch) && ((LIR_OpBranch*)op)->block() != NULL) {
6004 assert(false, "block with two successors can have only two branch instructions");
6005 }
6006 }
6007 #endif
6008
6009 // setup a list with the lir-instructions of all successors
6010 for (i = 0; i < num_sux; i++) {
6011 BlockBegin* sux = block->sux_at(i);
6012 LIR_OpList* sux_instructions = sux->lir()->instructions_list();
6013
6014 assert(sux_instructions->at(0)->code() == lir_label, "block must start with label");
6015
6016 if (sux->number_of_preds() != 1) {
6017 // this can happen with switch-statements where multiple edges are between
6018 // the same blocks.
6019 return;
6020 }
6021 assert(sux->pred_at(0) == block, "invalid control flow");
6022 assert(!sux->is_set(BlockBegin::exception_entry_flag), "exception handlers not allowed");
6023
6024 // ignore the label at the beginning of the block
6025 append_instructions(sux_instructions, 1);
6026 }
6027
6028 // process lir-instructions while all successors begin with the same instruction
6029 while (true) {
6030 LIR_Op* op = instruction_at(0);
6031 for (i = 1; i < num_sux; i++) {
6032 if (operations_different(op, instruction_at(i))) {
6033 // these instructions are different and cannot be optimized ->
6034 // no further optimization possible
6035 return;
6036 }
6037 }
6038
6039 TRACE_LINEAR_SCAN(4, tty->print("----- found instruction that is equal in all %d successors: ", num_sux); op->print());
6040
6041 // insert instruction at end of current block
6042 block->lir()->insert_before(insert_idx, op);
6043 insert_idx++;
6044
6045 // delete the instructions at the beginning of all successors
6046 for (i = 0; i < num_sux; i++) {
6047 remove_cur_instruction(i, false);
6048 }
6049 }
6050 }
6051
6052
6053 // Implementation of ControlFlowOptimizer
6054
6055 ControlFlowOptimizer::ControlFlowOptimizer() :
6056 _original_preds(4)
6057 {
6058 }
6059
6060 void ControlFlowOptimizer::optimize(BlockList* code) {
6061 ControlFlowOptimizer optimizer = ControlFlowOptimizer();
6062
6063 // push the OSR entry block to the end so that we're not jumping over it.
6064 BlockBegin* osr_entry = code->at(0)->end()->as_Base()->osr_entry();
6065 if (osr_entry) {
6066 int index = osr_entry->linear_scan_number();
6067 assert(code->at(index) == osr_entry, "wrong index");
6068 code->remove_at(index);
6069 code->append(osr_entry);
6070 }
6071
6072 optimizer.reorder_short_loops(code);
6073 optimizer.delete_empty_blocks(code);
6074 optimizer.delete_unnecessary_jumps(code);
6075 optimizer.delete_jumps_to_return(code);
6076 }
6077
6078 void ControlFlowOptimizer::reorder_short_loop(BlockList* code, BlockBegin* header_block, int header_idx) {
6079 int i = header_idx + 1;
6080 int max_end = MIN2(header_idx + ShortLoopSize, code->length());
6081 while (i < max_end && code->at(i)->loop_depth() >= header_block->loop_depth()) {
6082 i++;
6083 }
6084
6085 if (i == code->length() || code->at(i)->loop_depth() < header_block->loop_depth()) {
6086 int end_idx = i - 1;
6087 BlockBegin* end_block = code->at(end_idx);
6088
6089 if (end_block->number_of_sux() == 1 && end_block->sux_at(0) == header_block) {
6090 // short loop from header_idx to end_idx found -> reorder blocks such that
6091 // the header_block is the last block instead of the first block of the loop
6092 TRACE_LINEAR_SCAN(1, tty->print_cr("Reordering short loop: length %d, header B%d, end B%d",
6093 end_idx - header_idx + 1,
6094 header_block->block_id(), end_block->block_id()));
6095
6096 for (int j = header_idx; j < end_idx; j++) {
6097 code->at_put(j, code->at(j + 1));
6098 }
6099 code->at_put(end_idx, header_block);
6100
6101 // correct the flags so that any loop alignment occurs in the right place.
6102 assert(code->at(end_idx)->is_set(BlockBegin::backward_branch_target_flag), "must be backward branch target");
6103 code->at(end_idx)->clear(BlockBegin::backward_branch_target_flag);
6104 code->at(header_idx)->set(BlockBegin::backward_branch_target_flag);
6105 }
6106 }
6107 }
6108
6109 void ControlFlowOptimizer::reorder_short_loops(BlockList* code) {
6110 for (int i = code->length() - 1; i >= 0; i--) {
6111 BlockBegin* block = code->at(i);
6112
6113 if (block->is_set(BlockBegin::linear_scan_loop_header_flag)) {
6114 reorder_short_loop(code, block, i);
6115 }
6116 }
6117
6118 DEBUG_ONLY(verify(code));
6119 }
6120
6121 // only blocks with exactly one successor can be deleted. Such blocks
6122 // must always end with an unconditional branch to this successor
6123 bool ControlFlowOptimizer::can_delete_block(BlockBegin* block) {
6124 if (block->number_of_sux() != 1 || block->number_of_exception_handlers() != 0 || block->is_entry_block()) {
6125 return false;
6126 }
6127
6128 LIR_OpList* instructions = block->lir()->instructions_list();
6129
6130 assert(instructions->length() >= 2, "block must have label and branch");
6131 assert(instructions->at(0)->code() == lir_label, "first instruction must always be a label");
6132 assert(instructions->last()->as_OpBranch() != NULL, "last instrcution must always be a branch");
6133 assert(instructions->last()->as_OpBranch()->cond() == lir_cond_always, "branch must be unconditional");
6134 assert(instructions->last()->as_OpBranch()->block() == block->sux_at(0), "branch target must be the successor");
6135
6136 // block must have exactly one successor
6137
6138 if (instructions->length() == 2 && instructions->last()->info() == NULL) {
6139 return true;
6140 }
6141 return false;
6142 }
6143
6144 // substitute branch targets in all branch-instructions of this blocks
6145 void ControlFlowOptimizer::substitute_branch_target(BlockBegin* block, BlockBegin* target_from, BlockBegin* target_to) {
6146 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()));
6147
6148 LIR_OpList* instructions = block->lir()->instructions_list();
6149
6150 assert(instructions->at(0)->code() == lir_label, "first instruction must always be a label");
6151 for (int i = instructions->length() - 1; i >= 1; i--) {
6152 LIR_Op* op = instructions->at(i);
6153
6154 if (op->code() == lir_branch || op->code() == lir_cond_float_branch) {
6155 assert(op->as_OpBranch() != NULL, "branch must be of type LIR_OpBranch");
6156 LIR_OpBranch* branch = (LIR_OpBranch*)op;
6157
6158 if (branch->block() == target_from) {
6159 branch->change_block(target_to);
6160 }
6161 if (branch->ublock() == target_from) {
6162 branch->change_ublock(target_to);
6163 }
6164 }
6165 }
6166 }
6167
6168 void ControlFlowOptimizer::delete_empty_blocks(BlockList* code) {
6169 int old_pos = 0;
6170 int new_pos = 0;
6171 int num_blocks = code->length();
6172
6173 while (old_pos < num_blocks) {
6174 BlockBegin* block = code->at(old_pos);
6175
6176 if (can_delete_block(block)) {
6177 BlockBegin* new_target = block->sux_at(0);
6178
6179 // propagate backward branch target flag for correct code alignment
6180 if (block->is_set(BlockBegin::backward_branch_target_flag)) {
6181 new_target->set(BlockBegin::backward_branch_target_flag);
6182 }
6183
6184 // collect a list with all predecessors that contains each predecessor only once
6185 // the predecessors of cur are changed during the substitution, so a copy of the
6186 // predecessor list is necessary
6187 int j;
6188 _original_preds.clear();
6189 for (j = block->number_of_preds() - 1; j >= 0; j--) {
6190 BlockBegin* pred = block->pred_at(j);
6191 if (_original_preds.find(pred) == -1) {
6192 _original_preds.append(pred);
6193 }
6194 }
6195
6196 for (j = _original_preds.length() - 1; j >= 0; j--) {
6197 BlockBegin* pred = _original_preds.at(j);
6198 substitute_branch_target(pred, block, new_target);
6199 pred->substitute_sux(block, new_target);
6200 }
6201 } else {
6202 // adjust position of this block in the block list if blocks before
6203 // have been deleted
6204 if (new_pos != old_pos) {
6205 code->at_put(new_pos, code->at(old_pos));
6206 }
6207 new_pos++;
6208 }
6209 old_pos++;
6210 }
6211 code->trunc_to(new_pos);
6212
6213 DEBUG_ONLY(verify(code));
6214 }
6215
6216 void ControlFlowOptimizer::delete_unnecessary_jumps(BlockList* code) {
6217 // skip the last block because there a branch is always necessary
6218 for (int i = code->length() - 2; i >= 0; i--) {
6219 BlockBegin* block = code->at(i);
6220 LIR_OpList* instructions = block->lir()->instructions_list();
6221
6222 LIR_Op* last_op = instructions->last();
6223 if (last_op->code() == lir_branch) {
6224 assert(last_op->as_OpBranch() != NULL, "branch must be of type LIR_OpBranch");
6225 LIR_OpBranch* last_branch = (LIR_OpBranch*)last_op;
6226
6227 assert(last_branch->block() != NULL, "last branch must always have a block as target");
6228 assert(last_branch->label() == last_branch->block()->label(), "must be equal");
6229
6230 if (last_branch->info() == NULL) {
6231 if (last_branch->block() == code->at(i + 1)) {
6232
6233 TRACE_LINEAR_SCAN(3, tty->print_cr("Deleting unconditional branch at end of block B%d", block->block_id()));
6234
6235 // delete last branch instruction
6236 instructions->trunc_to(instructions->length() - 1);
6237
6238 } else {
6239 LIR_Op* prev_op = instructions->at(instructions->length() - 2);
6240 if (prev_op->code() == lir_branch || prev_op->code() == lir_cond_float_branch) {
6241 assert(prev_op->as_OpBranch() != NULL, "branch must be of type LIR_OpBranch");
6242 LIR_OpBranch* prev_branch = (LIR_OpBranch*)prev_op;
6243
6244 if (prev_branch->stub() == NULL) {
6245
6246 LIR_Op2* prev_cmp = NULL;
6247 // There might be a cmove inserted for profiling which depends on the same
6248 // compare. If we change the condition of the respective compare, we have
6249 // to take care of this cmove as well.
6250 LIR_Op2* prev_cmove = NULL;
6251
6252 for(int j = instructions->length() - 3; j >= 0 && prev_cmp == NULL; j--) {
6253 prev_op = instructions->at(j);
6254 // check for the cmove
6255 if (prev_op->code() == lir_cmove) {
6256 assert(prev_op->as_Op2() != NULL, "cmove must be of type LIR_Op2");
6257 prev_cmove = (LIR_Op2*)prev_op;
6258 assert(prev_branch->cond() == prev_cmove->condition(), "should be the same");
6259 }
6260 if (prev_op->code() == lir_cmp) {
6261 assert(prev_op->as_Op2() != NULL, "branch must be of type LIR_Op2");
6262 prev_cmp = (LIR_Op2*)prev_op;
6263 assert(prev_branch->cond() == prev_cmp->condition(), "should be the same");
6264 }
6265 }
6266 // Guarantee because it is dereferenced below.
6267 guarantee(prev_cmp != NULL, "should have found comp instruction for branch");
6268 if (prev_branch->block() == code->at(i + 1) && prev_branch->info() == NULL) {
6269
6270 TRACE_LINEAR_SCAN(3, tty->print_cr("Negating conditional branch and deleting unconditional branch at end of block B%d", block->block_id()));
6271
6272 // eliminate a conditional branch to the immediate successor
6273 prev_branch->change_block(last_branch->block());
6274 prev_branch->negate_cond();
6275 prev_cmp->set_condition(prev_branch->cond());
6276 instructions->trunc_to(instructions->length() - 1);
6277 // if we do change the condition, we have to change the cmove as well
6278 if (prev_cmove != NULL) {
6279 prev_cmove->set_condition(prev_branch->cond());
6280 LIR_Opr t = prev_cmove->in_opr1();
6281 prev_cmove->set_in_opr1(prev_cmove->in_opr2());
6282 prev_cmove->set_in_opr2(t);
6283 }
6284 }
6285 }
6286 }
6287 }
6288 }
6289 }
6290 }
6291
6292 DEBUG_ONLY(verify(code));
6293 }
6294
6295 void ControlFlowOptimizer::delete_jumps_to_return(BlockList* code) {
6296 #ifdef ASSERT
6297 ResourceBitMap return_converted(BlockBegin::number_of_blocks());
6298 #endif
6299
6300 for (int i = code->length() - 1; i >= 0; i--) {
6301 BlockBegin* block = code->at(i);
6302 LIR_OpList* cur_instructions = block->lir()->instructions_list();
6303 LIR_Op* cur_last_op = cur_instructions->last();
6304
6305 assert(cur_instructions->at(0)->code() == lir_label, "first instruction must always be a label");
6306 if (cur_instructions->length() == 2 && cur_last_op->code() == lir_return) {
6307 // the block contains only a label and a return
6308 // if a predecessor ends with an unconditional jump to this block, then the jump
6309 // can be replaced with a return instruction
6310 //
6311 // Note: the original block with only a return statement cannot be deleted completely
6312 // because the predecessors might have other (conditional) jumps to this block
6313 // -> this may lead to unnecesary return instructions in the final code
6314
6315 assert(cur_last_op->info() == NULL, "return instructions do not have debug information");
6316 assert(block->number_of_sux() == 0 ||
6317 (return_converted.at(block->block_id()) && block->number_of_sux() == 1),
6318 "blocks that end with return must not have successors");
6319
6320 assert(cur_last_op->as_Op1() != NULL, "return must be LIR_Op1");
6321 LIR_Opr return_opr = ((LIR_Op1*)cur_last_op)->in_opr();
6322
6323 for (int j = block->number_of_preds() - 1; j >= 0; j--) {
6324 BlockBegin* pred = block->pred_at(j);
6325 LIR_OpList* pred_instructions = pred->lir()->instructions_list();
6326 LIR_Op* pred_last_op = pred_instructions->last();
6327
6328 if (pred_last_op->code() == lir_branch) {
6329 assert(pred_last_op->as_OpBranch() != NULL, "branch must be LIR_OpBranch");
6330 LIR_OpBranch* pred_last_branch = (LIR_OpBranch*)pred_last_op;
6331
6332 if (pred_last_branch->block() == block && pred_last_branch->cond() == lir_cond_always && pred_last_branch->info() == NULL) {
6333 // replace the jump to a return with a direct return
6334 // Note: currently the edge between the blocks is not deleted
6335 pred_instructions->at_put(pred_instructions->length() - 1, new LIR_Op1(lir_return, return_opr));
6336 #ifdef ASSERT
6337 return_converted.set_bit(pred->block_id());
6338 #endif
6339 }
6340 }
6341 }
6342 }
6343 }
6344 }
6345
6346
6347 #ifdef ASSERT
6348 void ControlFlowOptimizer::verify(BlockList* code) {
6349 for (int i = 0; i < code->length(); i++) {
6350 BlockBegin* block = code->at(i);
6351 LIR_OpList* instructions = block->lir()->instructions_list();
6352
6353 int j;
6354 for (j = 0; j < instructions->length(); j++) {
6355 LIR_OpBranch* op_branch = instructions->at(j)->as_OpBranch();
6356
6357 if (op_branch != NULL) {
6358 assert(op_branch->block() == NULL || code->find(op_branch->block()) != -1, "branch target not valid");
6359 assert(op_branch->ublock() == NULL || code->find(op_branch->ublock()) != -1, "branch target not valid");
6360 }
6361 }
6362
6363 for (j = 0; j < block->number_of_sux() - 1; j++) {
6364 BlockBegin* sux = block->sux_at(j);
6365 assert(code->find(sux) != -1, "successor not valid");
6366 }
6367
6368 for (j = 0; j < block->number_of_preds() - 1; j++) {
6369 BlockBegin* pred = block->pred_at(j);
6370 assert(code->find(pred) != -1, "successor not valid");
6371 }
6372 }
6373 }
6374 #endif
6375
6376
6377 #ifndef PRODUCT
6378
6379 // Implementation of LinearStatistic
6380
6381 const char* LinearScanStatistic::counter_name(int counter_idx) {
6382 switch (counter_idx) {
6383 case counter_method: return "compiled methods";
6384 case counter_fpu_method: return "methods using fpu";
6385 case counter_loop_method: return "methods with loops";
6386 case counter_exception_method:return "methods with xhandler";
6387
6388 case counter_loop: return "loops";
6389 case counter_block: return "blocks";
6390 case counter_loop_block: return "blocks inside loop";
6391 case counter_exception_block: return "exception handler entries";
6392 case counter_interval: return "intervals";
6393 case counter_fixed_interval: return "fixed intervals";
6394 case counter_range: return "ranges";
6395 case counter_fixed_range: return "fixed ranges";
6396 case counter_use_pos: return "use positions";
6397 case counter_fixed_use_pos: return "fixed use positions";
6398 case counter_spill_slots: return "spill slots";
6399
6400 // counter for classes of lir instructions
6401 case counter_instruction: return "total instructions";
6402 case counter_label: return "labels";
6403 case counter_entry: return "method entries";
6404 case counter_return: return "method returns";
6405 case counter_call: return "method calls";
6406 case counter_move: return "moves";
6407 case counter_cmp: return "compare";
6408 case counter_cond_branch: return "conditional branches";
6409 case counter_uncond_branch: return "unconditional branches";
6410 case counter_stub_branch: return "branches to stub";
6411 case counter_alu: return "artithmetic + logic";
6412 case counter_alloc: return "allocations";
6413 case counter_sync: return "synchronisation";
6414 case counter_throw: return "throw";
6415 case counter_unwind: return "unwind";
6416 case counter_typecheck: return "type+null-checks";
6417 case counter_fpu_stack: return "fpu-stack";
6418 case counter_misc_inst: return "other instructions";
6419 case counter_other_inst: return "misc. instructions";
6420
6421 // counter for different types of moves
6422 case counter_move_total: return "total moves";
6423 case counter_move_reg_reg: return "register->register";
6424 case counter_move_reg_stack: return "register->stack";
6425 case counter_move_stack_reg: return "stack->register";
6426 case counter_move_stack_stack:return "stack->stack";
6427 case counter_move_reg_mem: return "register->memory";
6428 case counter_move_mem_reg: return "memory->register";
6429 case counter_move_const_any: return "constant->any";
6430
6431 case blank_line_1: return "";
6432 case blank_line_2: return "";
6433
6434 default: ShouldNotReachHere(); return "";
6435 }
6436 }
6437
6438 LinearScanStatistic::Counter LinearScanStatistic::base_counter(int counter_idx) {
6439 if (counter_idx == counter_fpu_method || counter_idx == counter_loop_method || counter_idx == counter_exception_method) {
6440 return counter_method;
6441 } else if (counter_idx == counter_loop_block || counter_idx == counter_exception_block) {
6442 return counter_block;
6443 } else if (counter_idx >= counter_instruction && counter_idx <= counter_other_inst) {
6444 return counter_instruction;
6445 } else if (counter_idx >= counter_move_total && counter_idx <= counter_move_const_any) {
6446 return counter_move_total;
6447 }
6448 return invalid_counter;
6449 }
6450
6451 LinearScanStatistic::LinearScanStatistic() {
6452 for (int i = 0; i < number_of_counters; i++) {
6453 _counters_sum[i] = 0;
6454 _counters_max[i] = -1;
6455 }
6456
6457 }
6458
6459 // add the method-local numbers to the total sum
6460 void LinearScanStatistic::sum_up(LinearScanStatistic &method_statistic) {
6461 for (int i = 0; i < number_of_counters; i++) {
6462 _counters_sum[i] += method_statistic._counters_sum[i];
6463 _counters_max[i] = MAX2(_counters_max[i], method_statistic._counters_sum[i]);
6464 }
6465 }
6466
6467 void LinearScanStatistic::print(const char* title) {
6468 if (CountLinearScan || TraceLinearScanLevel > 0) {
6469 tty->cr();
6470 tty->print_cr("***** LinearScan statistic - %s *****", title);
6471
6472 for (int i = 0; i < number_of_counters; i++) {
6473 if (_counters_sum[i] > 0 || _counters_max[i] >= 0) {
6474 tty->print("%25s: %8d", counter_name(i), _counters_sum[i]);
6475
6476 LinearScanStatistic::Counter cntr = base_counter(i);
6477 if (cntr != invalid_counter) {
6478 tty->print(" (%5.1f%%) ", _counters_sum[i] * 100.0 / _counters_sum[cntr]);
6479 } else {
6480 tty->print(" ");
6481 }
6482
6483 if (_counters_max[i] >= 0) {
6484 tty->print("%8d", _counters_max[i]);
6485 }
6486 }
6487 tty->cr();
6488 }
6489 }
6490 }
6491
6492 void LinearScanStatistic::collect(LinearScan* allocator) {
6493 inc_counter(counter_method);
6494 if (allocator->has_fpu_registers()) {
6495 inc_counter(counter_fpu_method);
6496 }
6497 if (allocator->num_loops() > 0) {
6498 inc_counter(counter_loop_method);
6499 }
6500 inc_counter(counter_loop, allocator->num_loops());
6501 inc_counter(counter_spill_slots, allocator->max_spills());
6502
6503 int i;
6504 for (i = 0; i < allocator->interval_count(); i++) {
6505 Interval* cur = allocator->interval_at(i);
6506
6507 if (cur != NULL) {
6508 inc_counter(counter_interval);
6509 inc_counter(counter_use_pos, cur->num_use_positions());
6510 if (LinearScan::is_precolored_interval(cur)) {
6511 inc_counter(counter_fixed_interval);
6512 inc_counter(counter_fixed_use_pos, cur->num_use_positions());
6513 }
6514
6515 Range* range = cur->first();
6516 while (range != Range::end()) {
6517 inc_counter(counter_range);
6518 if (LinearScan::is_precolored_interval(cur)) {
6519 inc_counter(counter_fixed_range);
6520 }
6521 range = range->next();
6522 }
6523 }
6524 }
6525
6526 bool has_xhandlers = false;
6527 // Note: only count blocks that are in code-emit order
6528 for (i = 0; i < allocator->ir()->code()->length(); i++) {
6529 BlockBegin* cur = allocator->ir()->code()->at(i);
6530
6531 inc_counter(counter_block);
6532 if (cur->loop_depth() > 0) {
6533 inc_counter(counter_loop_block);
6534 }
6535 if (cur->is_set(BlockBegin::exception_entry_flag)) {
6536 inc_counter(counter_exception_block);
6537 has_xhandlers = true;
6538 }
6539
6540 LIR_OpList* instructions = cur->lir()->instructions_list();
6541 for (int j = 0; j < instructions->length(); j++) {
6542 LIR_Op* op = instructions->at(j);
6543
6544 inc_counter(counter_instruction);
6545
6546 switch (op->code()) {
6547 case lir_label: inc_counter(counter_label); break;
6548 case lir_std_entry:
6549 case lir_osr_entry: inc_counter(counter_entry); break;
6550 case lir_return: inc_counter(counter_return); break;
6551
6552 case lir_rtcall:
6553 case lir_static_call:
6554 case lir_optvirtual_call:
6555 case lir_virtual_call: inc_counter(counter_call); break;
6556
6557 case lir_move: {
6558 inc_counter(counter_move);
6559 inc_counter(counter_move_total);
6560
6561 LIR_Opr in = op->as_Op1()->in_opr();
6562 LIR_Opr res = op->as_Op1()->result_opr();
6563 if (in->is_register()) {
6564 if (res->is_register()) {
6565 inc_counter(counter_move_reg_reg);
6566 } else if (res->is_stack()) {
6567 inc_counter(counter_move_reg_stack);
6568 } else if (res->is_address()) {
6569 inc_counter(counter_move_reg_mem);
6570 } else {
6571 ShouldNotReachHere();
6572 }
6573 } else if (in->is_stack()) {
6574 if (res->is_register()) {
6575 inc_counter(counter_move_stack_reg);
6576 } else {
6577 inc_counter(counter_move_stack_stack);
6578 }
6579 } else if (in->is_address()) {
6580 assert(res->is_register(), "must be");
6581 inc_counter(counter_move_mem_reg);
6582 } else if (in->is_constant()) {
6583 inc_counter(counter_move_const_any);
6584 } else {
6585 ShouldNotReachHere();
6586 }
6587 break;
6588 }
6589
6590 case lir_cmp: inc_counter(counter_cmp); break;
6591
6592 case lir_branch:
6593 case lir_cond_float_branch: {
6594 LIR_OpBranch* branch = op->as_OpBranch();
6595 if (branch->block() == NULL) {
6596 inc_counter(counter_stub_branch);
6597 } else if (branch->cond() == lir_cond_always) {
6598 inc_counter(counter_uncond_branch);
6599 } else {
6600 inc_counter(counter_cond_branch);
6601 }
6602 break;
6603 }
6604
6605 case lir_neg:
6606 case lir_add:
6607 case lir_sub:
6608 case lir_mul:
6609 case lir_mul_strictfp:
6610 case lir_div:
6611 case lir_div_strictfp:
6612 case lir_rem:
6613 case lir_sqrt:
6614 case lir_abs:
6615 case lir_log10:
6616 case lir_logic_and:
6617 case lir_logic_or:
6618 case lir_logic_xor:
6619 case lir_shl:
6620 case lir_shr:
6621 case lir_ushr: inc_counter(counter_alu); break;
6622
6623 case lir_alloc_object:
6624 case lir_alloc_array: inc_counter(counter_alloc); break;
6625
6626 case lir_monaddr:
6627 case lir_lock:
6628 case lir_unlock: inc_counter(counter_sync); break;
6629
6630 case lir_throw: inc_counter(counter_throw); break;
6631
6632 case lir_unwind: inc_counter(counter_unwind); break;
6633
6634 case lir_null_check:
6635 case lir_leal:
6636 case lir_instanceof:
6637 case lir_checkcast:
6638 case lir_store_check: inc_counter(counter_typecheck); break;
6639
6640 case lir_fpop_raw:
6641 case lir_fxch:
6642 case lir_fld: inc_counter(counter_fpu_stack); break;
6643
6644 case lir_nop:
6645 case lir_push:
6646 case lir_pop:
6647 case lir_convert:
6648 case lir_roundfp:
6649 case lir_cmove: inc_counter(counter_misc_inst); break;
6650
6651 default: inc_counter(counter_other_inst); break;
6652 }
6653 }
6654 }
6655
6656 if (has_xhandlers) {
6657 inc_counter(counter_exception_method);
6658 }
6659 }
6660
6661 void LinearScanStatistic::compute(LinearScan* allocator, LinearScanStatistic &global_statistic) {
6662 if (CountLinearScan || TraceLinearScanLevel > 0) {
6663
6664 LinearScanStatistic local_statistic = LinearScanStatistic();
6665
6666 local_statistic.collect(allocator);
6667 global_statistic.sum_up(local_statistic);
6668
6669 if (TraceLinearScanLevel > 2) {
6670 local_statistic.print("current local statistic");
6671 }
6672 }
6673 }
6674
6675
6676 // Implementation of LinearTimers
6677
6678 LinearScanTimers::LinearScanTimers() {
6679 for (int i = 0; i < number_of_timers; i++) {
6680 timer(i)->reset();
6681 }
6682 }
6683
6684 const char* LinearScanTimers::timer_name(int idx) {
6685 switch (idx) {
6686 case timer_do_nothing: return "Nothing (Time Check)";
6687 case timer_number_instructions: return "Number Instructions";
6688 case timer_compute_local_live_sets: return "Local Live Sets";
6689 case timer_compute_global_live_sets: return "Global Live Sets";
6690 case timer_build_intervals: return "Build Intervals";
6691 case timer_sort_intervals_before: return "Sort Intervals Before";
6692 case timer_allocate_registers: return "Allocate Registers";
6693 case timer_resolve_data_flow: return "Resolve Data Flow";
6694 case timer_sort_intervals_after: return "Sort Intervals After";
6695 case timer_eliminate_spill_moves: return "Spill optimization";
6696 case timer_assign_reg_num: return "Assign Reg Num";
6697 case timer_allocate_fpu_stack: return "Allocate FPU Stack";
6698 case timer_optimize_lir: return "Optimize LIR";
6699 default: ShouldNotReachHere(); return "";
6700 }
6701 }
6702
6703 void LinearScanTimers::begin_method() {
6704 if (TimeEachLinearScan) {
6705 // reset all timers to measure only current method
6706 for (int i = 0; i < number_of_timers; i++) {
6707 timer(i)->reset();
6708 }
6709 }
6710 }
6711
6712 void LinearScanTimers::end_method(LinearScan* allocator) {
6713 if (TimeEachLinearScan) {
6714
6715 double c = timer(timer_do_nothing)->seconds();
6716 double total = 0;
6717 for (int i = 1; i < number_of_timers; i++) {
6718 total += timer(i)->seconds() - c;
6719 }
6720
6721 if (total >= 0.0005) {
6722 // print all information in one line for automatic processing
6723 tty->print("@"); allocator->compilation()->method()->print_name();
6724
6725 tty->print("@ %d ", allocator->compilation()->method()->code_size());
6726 tty->print("@ %d ", allocator->block_at(allocator->block_count() - 1)->last_lir_instruction_id() / 2);
6727 tty->print("@ %d ", allocator->block_count());
6728 tty->print("@ %d ", allocator->num_virtual_regs());
6729 tty->print("@ %d ", allocator->interval_count());
6730 tty->print("@ %d ", allocator->_num_calls);
6731 tty->print("@ %d ", allocator->num_loops());
6732
6733 tty->print("@ %6.6f ", total);
6734 for (int i = 1; i < number_of_timers; i++) {
6735 tty->print("@ %4.1f ", ((timer(i)->seconds() - c) / total) * 100);
6736 }
6737 tty->cr();
6738 }
6739 }
6740 }
6741
6742 void LinearScanTimers::print(double total_time) {
6743 if (TimeLinearScan) {
6744 // correction value: sum of dummy-timer that only measures the time that
6745 // is necesary to start and stop itself
6746 double c = timer(timer_do_nothing)->seconds();
6747
6748 for (int i = 0; i < number_of_timers; i++) {
6749 double t = timer(i)->seconds();
6750 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);
6751 }
6752 }
6753 }
6754
6755 #endif // #ifndef PRODUCT