1 /*
2 * Copyright (c) 2005, 2025, 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 "c1/c1_CFGPrinter.hpp"
26 #include "c1/c1_CodeStubs.hpp"
27 #include "c1/c1_Compilation.hpp"
28 #include "c1/c1_FrameMap.hpp"
29 #include "c1/c1_IR.hpp"
30 #include "c1/c1_LinearScan.hpp"
31 #include "c1/c1_LIRGenerator.hpp"
32 #include "c1/c1_ValueStack.hpp"
33 #include "code/vmreg.inline.hpp"
34 #include "runtime/timerTrace.hpp"
35 #include "utilities/bitMap.inline.hpp"
36
37 #ifndef PRODUCT
38
39 static LinearScanStatistic _stat_before_alloc;
40 static LinearScanStatistic _stat_after_asign;
41 static LinearScanStatistic _stat_final;
42
43 static LinearScanTimers _total_timer;
44
45 // helper macro for short definition of timer
46 #define TIME_LINEAR_SCAN(timer_name) TraceTime _block_timer("", _total_timer.timer(LinearScanTimers::timer_name), TimeLinearScan || TimeEachLinearScan, Verbose);
47
48 #else
49 #define TIME_LINEAR_SCAN(timer_name)
50 #endif
51
52 #ifdef ASSERT
53
54 // helper macro for short definition of trace-output inside code
55 #define TRACE_LINEAR_SCAN(level, code) \
56 if (TraceLinearScanLevel >= level) { \
57 code; \
58 }
59 #else
60 #define TRACE_LINEAR_SCAN(level, code)
61 #endif
62
63 // Map BasicType to spill size in 32-bit words, matching VMReg's notion of words
64 #ifdef _LP64
65 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};
66 #else
67 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};
68 #endif
69
70
71 // Implementation of LinearScan
72
73 LinearScan::LinearScan(IR* ir, LIRGenerator* gen, FrameMap* frame_map)
74 : _compilation(ir->compilation())
75 , _ir(ir)
76 , _gen(gen)
77 , _frame_map(frame_map)
78 , _cached_blocks(*ir->linear_scan_order())
79 , _num_virtual_regs(gen->max_virtual_register_number())
80 , _has_fpu_registers(false)
81 , _num_calls(-1)
82 , _max_spills(0)
83 , _unused_spill_slot(-1)
84 , _intervals(0) // initialized later with correct length
85 , _new_intervals_from_allocation(nullptr)
86 , _sorted_intervals(nullptr)
87 , _needs_full_resort(false)
88 , _lir_ops(0) // initialized later with correct length
89 , _block_of_op(0) // initialized later with correct length
90 , _has_info(0)
91 , _has_call(0)
92 , _interval_in_loop(0) // initialized later with correct length
93 , _scope_value_cache(0) // initialized later with correct length
94 {
95 assert(this->ir() != nullptr, "check if valid");
96 assert(this->compilation() != nullptr, "check if valid");
97 assert(this->gen() != nullptr, "check if valid");
98 assert(this->frame_map() != nullptr, "check if valid");
99 }
100
101
102 // ********** functions for converting LIR-Operands to register numbers
103 //
104 // Emulate a flat register file comprising physical integer registers,
105 // physical floating-point registers and virtual registers, in that order.
106 // Virtual registers already have appropriate numbers, since V0 is
107 // the number of physical registers.
108 // Returns -1 for hi word if opr is a single word operand.
109 //
110 // Note: the inverse operation (calculating an operand for register numbers)
111 // is done in calc_operand_for_interval()
112
113 int LinearScan::reg_num(LIR_Opr opr) {
114 assert(opr->is_register(), "should not call this otherwise");
115
116 if (opr->is_virtual_register()) {
117 assert(opr->vreg_number() >= nof_regs, "found a virtual register with a fixed-register number");
118 return opr->vreg_number();
119 } else if (opr->is_single_cpu()) {
120 return opr->cpu_regnr();
121 } else if (opr->is_double_cpu()) {
122 return opr->cpu_regnrLo();
123 #ifdef X86
124 } else if (opr->is_single_xmm()) {
125 return opr->fpu_regnr() + pd_first_xmm_reg;
126 } else if (opr->is_double_xmm()) {
127 return opr->fpu_regnrLo() + pd_first_xmm_reg;
128 #endif
129 } else if (opr->is_single_fpu()) {
130 return opr->fpu_regnr() + pd_first_fpu_reg;
131 } else if (opr->is_double_fpu()) {
132 return opr->fpu_regnrLo() + pd_first_fpu_reg;
133 } else {
134 ShouldNotReachHere();
135 return -1;
136 }
137 }
138
139 int LinearScan::reg_numHi(LIR_Opr opr) {
140 assert(opr->is_register(), "should not call this otherwise");
141
142 if (opr->is_virtual_register()) {
143 return -1;
144 } else if (opr->is_single_cpu()) {
145 return -1;
146 } else if (opr->is_double_cpu()) {
147 return opr->cpu_regnrHi();
148 #ifdef X86
149 } else if (opr->is_single_xmm()) {
150 return -1;
151 } else if (opr->is_double_xmm()) {
152 return -1;
153 #endif
154 } else if (opr->is_single_fpu()) {
155 return -1;
156 } else if (opr->is_double_fpu()) {
157 return opr->fpu_regnrHi() + pd_first_fpu_reg;
158 } else {
159 ShouldNotReachHere();
160 return -1;
161 }
162 }
163
164
165 // ********** functions for classification of intervals
166
167 bool LinearScan::is_precolored_interval(const Interval* i) {
168 return i->reg_num() < LinearScan::nof_regs;
169 }
170
171 bool LinearScan::is_virtual_interval(const Interval* i) {
172 return i->reg_num() >= LIR_Opr::vreg_base;
173 }
174
175 bool LinearScan::is_precolored_cpu_interval(const Interval* i) {
176 return i->reg_num() < LinearScan::nof_cpu_regs;
177 }
178
179 bool LinearScan::is_virtual_cpu_interval(const Interval* i) {
180 #if defined(__SOFTFP__) || defined(E500V2)
181 return i->reg_num() >= LIR_Opr::vreg_base;
182 #else
183 return i->reg_num() >= LIR_Opr::vreg_base && (i->type() != T_FLOAT && i->type() != T_DOUBLE);
184 #endif // __SOFTFP__ or E500V2
185 }
186
187 bool LinearScan::is_precolored_fpu_interval(const Interval* i) {
188 return i->reg_num() >= LinearScan::nof_cpu_regs && i->reg_num() < LinearScan::nof_regs;
189 }
190
191 bool LinearScan::is_virtual_fpu_interval(const Interval* i) {
192 #if defined(__SOFTFP__) || defined(E500V2)
193 return false;
194 #else
195 return i->reg_num() >= LIR_Opr::vreg_base && (i->type() == T_FLOAT || i->type() == T_DOUBLE);
196 #endif // __SOFTFP__ or E500V2
197 }
198
199 bool LinearScan::is_in_fpu_register(const Interval* i) {
200 // fixed intervals not needed for FPU stack allocation
201 return i->reg_num() >= nof_regs && pd_first_fpu_reg <= i->assigned_reg() && i->assigned_reg() <= pd_last_fpu_reg;
202 }
203
204 bool LinearScan::is_oop_interval(const Interval* i) {
205 // fixed intervals never contain oops
206 return i->reg_num() >= nof_regs && i->type() == T_OBJECT;
207 }
208
209
210 // ********** General helper functions
211
212 // compute next unused stack index that can be used for spilling
213 int LinearScan::allocate_spill_slot(bool double_word) {
214 int spill_slot;
215 if (double_word) {
216 if ((_max_spills & 1) == 1) {
217 // alignment of double-word values
218 // the hole because of the alignment is filled with the next single-word value
219 assert(_unused_spill_slot == -1, "wasting a spill slot");
220 _unused_spill_slot = _max_spills;
221 _max_spills++;
222 }
223 spill_slot = _max_spills;
224 _max_spills += 2;
225
226 } else if (_unused_spill_slot != -1) {
227 // re-use hole that was the result of a previous double-word alignment
228 spill_slot = _unused_spill_slot;
229 _unused_spill_slot = -1;
230
231 } else {
232 spill_slot = _max_spills;
233 _max_spills++;
234 }
235
236 int result = spill_slot + LinearScan::nof_regs + frame_map()->argcount();
237
238 // if too many slots used, bailout compilation.
239 if (result > 2000) {
240 bailout("too many stack slots used");
241 }
242
243 return result;
244 }
245
246 void LinearScan::assign_spill_slot(Interval* it) {
247 // assign the canonical spill slot of the parent (if a part of the interval
248 // is already spilled) or allocate a new spill slot
249 if (it->canonical_spill_slot() >= 0) {
250 it->assign_reg(it->canonical_spill_slot());
251 } else {
252 int spill = allocate_spill_slot(type2spill_size[it->type()] == 2);
253 it->set_canonical_spill_slot(spill);
254 it->assign_reg(spill);
255 }
256 }
257
258 void LinearScan::propagate_spill_slots() {
259 if (!frame_map()->finalize_frame(max_spills())) {
260 bailout("frame too large");
261 }
262 }
263
264 // create a new interval with a predefined reg_num
265 // (only used for parent intervals that are created during the building phase)
266 Interval* LinearScan::create_interval(int reg_num) {
267 assert(_intervals.at(reg_num) == nullptr, "overwriting existing interval");
268
269 Interval* interval = new Interval(reg_num);
270 _intervals.at_put(reg_num, interval);
271
272 // assign register number for precolored intervals
273 if (reg_num < LIR_Opr::vreg_base) {
274 interval->assign_reg(reg_num);
275 }
276 return interval;
277 }
278
279 // assign a new reg_num to the interval and append it to the list of intervals
280 // (only used for child intervals that are created during register allocation)
281 void LinearScan::append_interval(Interval* it) {
282 it->set_reg_num(_intervals.length());
283 _intervals.append(it);
284 IntervalList* new_intervals = _new_intervals_from_allocation;
285 if (new_intervals == nullptr) {
286 new_intervals = _new_intervals_from_allocation = new IntervalList();
287 }
288 new_intervals->append(it);
289 }
290
291 // copy the vreg-flags if an interval is split
292 void LinearScan::copy_register_flags(Interval* from, Interval* to) {
293 if (gen()->is_vreg_flag_set(from->reg_num(), LIRGenerator::byte_reg)) {
294 gen()->set_vreg_flag(to->reg_num(), LIRGenerator::byte_reg);
295 }
296 if (gen()->is_vreg_flag_set(from->reg_num(), LIRGenerator::callee_saved)) {
297 gen()->set_vreg_flag(to->reg_num(), LIRGenerator::callee_saved);
298 }
299
300 // Note: do not copy the must_start_in_memory flag because it is not necessary for child
301 // intervals (only the very beginning of the interval must be in memory)
302 }
303
304
305 // ********** spill move optimization
306 // eliminate moves from register to stack if stack slot is known to be correct
307
308 // called during building of intervals
309 void LinearScan::change_spill_definition_pos(Interval* interval, int def_pos) {
310 assert(interval->is_split_parent(), "can only be called for split parents");
311
312 switch (interval->spill_state()) {
313 case noDefinitionFound:
314 assert(interval->spill_definition_pos() == -1, "must no be set before");
315 interval->set_spill_definition_pos(def_pos);
316 interval->set_spill_state(oneDefinitionFound);
317 break;
318
319 case oneDefinitionFound:
320 assert(def_pos <= interval->spill_definition_pos(), "positions are processed in reverse order when intervals are created");
321 if (def_pos < interval->spill_definition_pos() - 2) {
322 // second definition found, so no spill optimization possible for this interval
323 interval->set_spill_state(noOptimization);
324 } else {
325 // two consecutive definitions (because of two-operand LIR form)
326 assert(block_of_op_with_id(def_pos) == block_of_op_with_id(interval->spill_definition_pos()), "block must be equal");
327 }
328 break;
329
330 case noOptimization:
331 // nothing to do
332 break;
333
334 default:
335 assert(false, "other states not allowed at this time");
336 }
337 }
338
339 // called during register allocation
340 void LinearScan::change_spill_state(Interval* interval, int spill_pos) {
341 switch (interval->spill_state()) {
342 case oneDefinitionFound: {
343 int def_loop_depth = block_of_op_with_id(interval->spill_definition_pos())->loop_depth();
344 int spill_loop_depth = block_of_op_with_id(spill_pos)->loop_depth();
345
346 if (def_loop_depth < spill_loop_depth) {
347 // the loop depth of the spilling position is higher then the loop depth
348 // at the definition of the interval -> move write to memory out of loop
349 // by storing at definitin of the interval
350 interval->set_spill_state(storeAtDefinition);
351 } else {
352 // the interval is currently spilled only once, so for now there is no
353 // reason to store the interval at the definition
354 interval->set_spill_state(oneMoveInserted);
355 }
356 break;
357 }
358
359 case oneMoveInserted: {
360 // the interval is spilled more then once, so it is better to store it to
361 // memory at the definition
362 interval->set_spill_state(storeAtDefinition);
363 break;
364 }
365
366 case storeAtDefinition:
367 case startInMemory:
368 case noOptimization:
369 case noDefinitionFound:
370 // nothing to do
371 break;
372
373 default:
374 assert(false, "other states not allowed at this time");
375 }
376 }
377
378
379 bool LinearScan::must_store_at_definition(const Interval* i) {
380 return i->is_split_parent() && i->spill_state() == storeAtDefinition;
381 }
382
383 // called once before assignment of register numbers
384 void LinearScan::eliminate_spill_moves() {
385 TIME_LINEAR_SCAN(timer_eliminate_spill_moves);
386 TRACE_LINEAR_SCAN(3, tty->print_cr("***** Eliminating unnecessary spill moves"));
387
388 // collect all intervals that must be stored after their definion.
389 // the list is sorted by Interval::spill_definition_pos
390 Interval* interval;
391 Interval* temp_list;
392 create_unhandled_lists(&interval, &temp_list, must_store_at_definition, nullptr);
393
394 #ifdef ASSERT
395 Interval* prev = nullptr;
396 Interval* temp = interval;
397 while (temp != Interval::end()) {
398 assert(temp->spill_definition_pos() > 0, "invalid spill definition pos");
399 if (prev != nullptr) {
400 assert(temp->from() >= prev->from(), "intervals not sorted");
401 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");
402 }
403
404 assert(temp->canonical_spill_slot() >= LinearScan::nof_regs, "interval has no spill slot assigned");
405 assert(temp->spill_definition_pos() >= temp->from(), "invalid order");
406 assert(temp->spill_definition_pos() <= temp->from() + 2, "only intervals defined once at their start-pos can be optimized");
407
408 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()));
409
410 temp = temp->next();
411 }
412 #endif
413
414 LIR_InsertionBuffer insertion_buffer;
415 int num_blocks = block_count();
416 for (int i = 0; i < num_blocks; i++) {
417 BlockBegin* block = block_at(i);
418 LIR_OpList* instructions = block->lir()->instructions_list();
419 int num_inst = instructions->length();
420 bool has_new = false;
421
422 // iterate all instructions of the block. skip the first because it is always a label
423 for (int j = 1; j < num_inst; j++) {
424 LIR_Op* op = instructions->at(j);
425 int op_id = op->id();
426
427 if (op_id == -1) {
428 // remove move from register to stack if the stack slot is guaranteed to be correct.
429 // only moves that have been inserted by LinearScan can be removed.
430 assert(op->code() == lir_move, "only moves can have a op_id of -1");
431 assert(op->as_Op1() != nullptr, "move must be LIR_Op1");
432 assert(op->as_Op1()->result_opr()->is_virtual(), "LinearScan inserts only moves to virtual registers");
433
434 LIR_Op1* op1 = (LIR_Op1*)op;
435 Interval* interval = interval_at(op1->result_opr()->vreg_number());
436
437 if (interval->assigned_reg() >= LinearScan::nof_regs && interval->always_in_memory()) {
438 // move target is a stack slot that is always correct, so eliminate instruction
439 TRACE_LINEAR_SCAN(4, tty->print_cr("eliminating move from interval %d to %d", op1->in_opr()->vreg_number(), op1->result_opr()->vreg_number()));
440 instructions->at_put(j, nullptr); // null-instructions are deleted by assign_reg_num
441 }
442
443 } else {
444 // insert move from register to stack just after the beginning of the interval
445 assert(interval == Interval::end() || interval->spill_definition_pos() >= op_id, "invalid order");
446 assert(interval == Interval::end() || (interval->is_split_parent() && interval->spill_state() == storeAtDefinition), "invalid interval");
447
448 while (interval != Interval::end() && interval->spill_definition_pos() == op_id) {
449 if (!has_new) {
450 // prepare insertion buffer (appended when all instructions of the block are processed)
451 insertion_buffer.init(block->lir());
452 has_new = true;
453 }
454
455 LIR_Opr from_opr = operand_for_interval(interval);
456 LIR_Opr to_opr = canonical_spill_opr(interval);
457 assert(from_opr->is_fixed_cpu() || from_opr->is_fixed_fpu(), "from operand must be a register");
458 assert(to_opr->is_stack(), "to operand must be a stack slot");
459
460 insertion_buffer.move(j, from_opr, to_opr);
461 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));
462
463 interval = interval->next();
464 }
465 }
466 } // end of instruction iteration
467
468 if (has_new) {
469 block->lir()->append(&insertion_buffer);
470 }
471 } // end of block iteration
472
473 assert(interval == Interval::end(), "missed an interval");
474 }
475
476
477 // ********** Phase 1: number all instructions in all blocks
478 // Compute depth-first and linear scan block orders, and number LIR_Op nodes for linear scan.
479
480 void LinearScan::number_instructions() {
481 {
482 // dummy-timer to measure the cost of the timer itself
483 // (this time is then subtracted from all other timers to get the real value)
484 TIME_LINEAR_SCAN(timer_do_nothing);
485 }
486 TIME_LINEAR_SCAN(timer_number_instructions);
487
488 // Assign IDs to LIR nodes and build a mapping, lir_ops, from ID to LIR_Op node.
489 int num_blocks = block_count();
490 int num_instructions = 0;
491 int i;
492 for (i = 0; i < num_blocks; i++) {
493 num_instructions += block_at(i)->lir()->instructions_list()->length();
494 }
495
496 // initialize with correct length
497 _lir_ops = LIR_OpArray(num_instructions, num_instructions, nullptr);
498 _block_of_op = BlockBeginArray(num_instructions, num_instructions, nullptr);
499
500 int op_id = 0;
501 int idx = 0;
502
503 for (i = 0; i < num_blocks; i++) {
504 BlockBegin* block = block_at(i);
505 block->set_first_lir_instruction_id(op_id);
506 LIR_OpList* instructions = block->lir()->instructions_list();
507
508 int num_inst = instructions->length();
509 for (int j = 0; j < num_inst; j++) {
510 LIR_Op* op = instructions->at(j);
511 op->set_id(op_id);
512
513 _lir_ops.at_put(idx, op);
514 _block_of_op.at_put(idx, block);
515 assert(lir_op_with_id(op_id) == op, "must match");
516
517 idx++;
518 op_id += 2; // numbering of lir_ops by two
519 }
520 block->set_last_lir_instruction_id(op_id - 2);
521 }
522 assert(idx == num_instructions, "must match");
523 assert(idx * 2 == op_id, "must match");
524
525 _has_call.initialize(num_instructions);
526 _has_info.initialize(num_instructions);
527 }
528
529
530 // ********** Phase 2: compute local live sets separately for each block
531 // (sets live_gen and live_kill for each block)
532
533 void LinearScan::set_live_gen_kill(Value value, LIR_Op* op, BitMap& live_gen, BitMap& live_kill) {
534 LIR_Opr opr = value->operand();
535 Constant* con = value->as_Constant();
536
537 // check some asumptions about debug information
538 assert(!value->type()->is_illegal(), "if this local is used by the interpreter it shouldn't be of indeterminate type");
539 assert(con == nullptr || opr->is_virtual() || opr->is_constant() || opr->is_illegal(), "assumption: Constant instructions have only constant operands");
540 assert(con != nullptr || opr->is_virtual(), "assumption: non-Constant instructions have only virtual operands");
541
542 if ((con == nullptr || con->is_pinned()) && opr->is_register()) {
543 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
544 int reg = opr->vreg_number();
545 if (!live_kill.at(reg)) {
546 live_gen.set_bit(reg);
547 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));
548 }
549 }
550 }
551
552
553 void LinearScan::compute_local_live_sets() {
554 TIME_LINEAR_SCAN(timer_compute_local_live_sets);
555
556 int num_blocks = block_count();
557 int live_size = live_set_size();
558 bool local_has_fpu_registers = false;
559 int local_num_calls = 0;
560 LIR_OpVisitState visitor;
561
562 BitMap2D local_interval_in_loop = BitMap2D(_num_virtual_regs, num_loops());
563
564 // iterate all blocks
565 for (int i = 0; i < num_blocks; i++) {
566 BlockBegin* block = block_at(i);
567
568 ResourceBitMap live_gen(live_size);
569 ResourceBitMap live_kill(live_size);
570
571 if (block->is_set(BlockBegin::exception_entry_flag)) {
572 // Phi functions at the begin of an exception handler are
573 // implicitly defined (= killed) at the beginning of the block.
574 for_each_phi_fun(block, phi,
575 if (!phi->is_illegal()) { live_kill.set_bit(phi->operand()->vreg_number()); }
576 );
577 }
578
579 LIR_OpList* instructions = block->lir()->instructions_list();
580 int num_inst = instructions->length();
581
582 // iterate all instructions of the block. skip the first because it is always a label
583 assert(visitor.no_operands(instructions->at(0)), "first operation must always be a label");
584 for (int j = 1; j < num_inst; j++) {
585 LIR_Op* op = instructions->at(j);
586
587 // visit operation to collect all operands
588 visitor.visit(op);
589
590 if (visitor.has_call()) {
591 _has_call.set_bit(op->id() >> 1);
592 local_num_calls++;
593 }
594 if (visitor.info_count() > 0) {
595 _has_info.set_bit(op->id() >> 1);
596 }
597
598 // iterate input operands of instruction
599 int k, n, reg;
600 n = visitor.opr_count(LIR_OpVisitState::inputMode);
601 for (k = 0; k < n; k++) {
602 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::inputMode, k);
603 assert(opr->is_register(), "visitor should only return register operands");
604
605 if (opr->is_virtual_register()) {
606 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
607 reg = opr->vreg_number();
608 if (!live_kill.at(reg)) {
609 live_gen.set_bit(reg);
610 TRACE_LINEAR_SCAN(4, tty->print_cr(" Setting live_gen for register %d at instruction %d", reg, op->id()));
611 }
612 if (block->loop_index() >= 0) {
613 local_interval_in_loop.set_bit(reg, block->loop_index());
614 }
615 local_has_fpu_registers = local_has_fpu_registers || opr->is_virtual_fpu();
616 }
617
618 #ifdef ASSERT
619 // fixed intervals are never live at block boundaries, so
620 // they need not be processed in live sets.
621 // this is checked by these assertions to be sure about it.
622 // the entry block may have incoming values in registers, which is ok.
623 if (!opr->is_virtual_register() && block != ir()->start()) {
624 reg = reg_num(opr);
625 if (is_processed_reg_num(reg)) {
626 assert(live_kill.at(reg), "using fixed register that is not defined in this block");
627 }
628 reg = reg_numHi(opr);
629 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
630 assert(live_kill.at(reg), "using fixed register that is not defined in this block");
631 }
632 }
633 #endif
634 }
635
636 // Add uses of live locals from interpreter's point of view for proper debug information generation
637 n = visitor.info_count();
638 for (k = 0; k < n; k++) {
639 CodeEmitInfo* info = visitor.info_at(k);
640 ValueStack* stack = info->stack();
641 for_each_state_value(stack, value,
642 set_live_gen_kill(value, op, live_gen, live_kill);
643 local_has_fpu_registers = local_has_fpu_registers || value->type()->is_float_kind();
644 );
645 }
646
647 // iterate temp operands of instruction
648 n = visitor.opr_count(LIR_OpVisitState::tempMode);
649 for (k = 0; k < n; k++) {
650 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::tempMode, k);
651 assert(opr->is_register(), "visitor should only return register operands");
652
653 if (opr->is_virtual_register()) {
654 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
655 reg = opr->vreg_number();
656 live_kill.set_bit(reg);
657 if (block->loop_index() >= 0) {
658 local_interval_in_loop.set_bit(reg, block->loop_index());
659 }
660 local_has_fpu_registers = local_has_fpu_registers || opr->is_virtual_fpu();
661 }
662
663 #ifdef ASSERT
664 // fixed intervals are never live at block boundaries, so
665 // they need not be processed in live sets
666 // process them only in debug mode so that this can be checked
667 if (!opr->is_virtual_register()) {
668 reg = reg_num(opr);
669 if (is_processed_reg_num(reg)) {
670 live_kill.set_bit(reg_num(opr));
671 }
672 reg = reg_numHi(opr);
673 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
674 live_kill.set_bit(reg);
675 }
676 }
677 #endif
678 }
679
680 // iterate output operands of instruction
681 n = visitor.opr_count(LIR_OpVisitState::outputMode);
682 for (k = 0; k < n; k++) {
683 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::outputMode, k);
684 assert(opr->is_register(), "visitor should only return register operands");
685
686 if (opr->is_virtual_register()) {
687 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
688 reg = opr->vreg_number();
689 live_kill.set_bit(reg);
690 if (block->loop_index() >= 0) {
691 local_interval_in_loop.set_bit(reg, block->loop_index());
692 }
693 local_has_fpu_registers = local_has_fpu_registers || opr->is_virtual_fpu();
694 }
695
696 #ifdef ASSERT
697 // fixed intervals are never live at block boundaries, so
698 // they need not be processed in live sets
699 // process them only in debug mode so that this can be checked
700 if (!opr->is_virtual_register()) {
701 reg = reg_num(opr);
702 if (is_processed_reg_num(reg)) {
703 live_kill.set_bit(reg_num(opr));
704 }
705 reg = reg_numHi(opr);
706 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
707 live_kill.set_bit(reg);
708 }
709 }
710 #endif
711 }
712 } // end of instruction iteration
713
714 block->set_live_gen (live_gen);
715 block->set_live_kill(live_kill);
716 block->set_live_in (ResourceBitMap(live_size));
717 block->set_live_out (ResourceBitMap(live_size));
718
719 TRACE_LINEAR_SCAN(4, tty->print("live_gen B%d ", block->block_id()); print_bitmap(block->live_gen()));
720 TRACE_LINEAR_SCAN(4, tty->print("live_kill B%d ", block->block_id()); print_bitmap(block->live_kill()));
721 } // end of block iteration
722
723 // propagate local calculated information into LinearScan object
724 _has_fpu_registers = local_has_fpu_registers;
725 compilation()->set_has_fpu_code(local_has_fpu_registers);
726
727 _num_calls = local_num_calls;
728 _interval_in_loop = local_interval_in_loop;
729 }
730
731
732 // ********** Phase 3: perform a backward dataflow analysis to compute global live sets
733 // (sets live_in and live_out for each block)
734
735 void LinearScan::compute_global_live_sets() {
736 TIME_LINEAR_SCAN(timer_compute_global_live_sets);
737
738 int num_blocks = block_count();
739 bool change_occurred;
740 bool change_occurred_in_block;
741 int iteration_count = 0;
742 ResourceBitMap live_out(live_set_size()); // scratch set for calculations
743
744 // Perform a backward dataflow analysis to compute live_out and live_in for each block.
745 // The loop is executed until a fixpoint is reached (no changes in an iteration)
746 // Exception handlers must be processed because not all live values are
747 // present in the state array, e.g. because of global value numbering
748 do {
749 change_occurred = false;
750
751 // iterate all blocks in reverse order
752 for (int i = num_blocks - 1; i >= 0; i--) {
753 BlockBegin* block = block_at(i);
754
755 change_occurred_in_block = false;
756
757 // live_out(block) is the union of live_in(sux), for successors sux of block
758 int n = block->number_of_sux();
759 int e = block->number_of_exception_handlers();
760 if (n + e > 0) {
761 // block has successors
762 if (n > 0) {
763 live_out.set_from(block->sux_at(0)->live_in());
764 for (int j = 1; j < n; j++) {
765 live_out.set_union(block->sux_at(j)->live_in());
766 }
767 } else {
768 live_out.clear();
769 }
770 for (int j = 0; j < e; j++) {
771 live_out.set_union(block->exception_handler_at(j)->live_in());
772 }
773
774 if (!block->live_out().is_same(live_out)) {
775 // A change occurred. Swap the old and new live out sets to avoid copying.
776 ResourceBitMap temp = block->live_out();
777 block->set_live_out(live_out);
778 live_out = temp;
779
780 change_occurred = true;
781 change_occurred_in_block = true;
782 }
783 }
784
785 if (iteration_count == 0 || change_occurred_in_block) {
786 // live_in(block) is the union of live_gen(block) with (live_out(block) & !live_kill(block))
787 // note: live_in has to be computed only in first iteration or if live_out has changed!
788 ResourceBitMap live_in = block->live_in();
789 live_in.set_from(block->live_out());
790 live_in.set_difference(block->live_kill());
791 live_in.set_union(block->live_gen());
792 }
793
794 #ifdef ASSERT
795 if (TraceLinearScanLevel >= 4) {
796 char c = ' ';
797 if (iteration_count == 0 || change_occurred_in_block) {
798 c = '*';
799 }
800 tty->print("(%d) live_in%c B%d ", iteration_count, c, block->block_id()); print_bitmap(block->live_in());
801 tty->print("(%d) live_out%c B%d ", iteration_count, c, block->block_id()); print_bitmap(block->live_out());
802 }
803 #endif
804 }
805 iteration_count++;
806
807 if (change_occurred && iteration_count > 50) {
808 BAILOUT("too many iterations in compute_global_live_sets");
809 }
810 } while (change_occurred);
811
812
813 #ifdef ASSERT
814 // check that fixed intervals are not live at block boundaries
815 // (live set must be empty at fixed intervals)
816 for (int i = 0; i < num_blocks; i++) {
817 BlockBegin* block = block_at(i);
818 for (int j = 0; j < LIR_Opr::vreg_base; j++) {
819 assert(block->live_in().at(j) == false, "live_in set of fixed register must be empty");
820 assert(block->live_out().at(j) == false, "live_out set of fixed register must be empty");
821 assert(block->live_gen().at(j) == false, "live_gen set of fixed register must be empty");
822 }
823 }
824 #endif
825
826 // check that the live_in set of the first block is empty
827 ResourceBitMap live_in_args(ir()->start()->live_in().size());
828 if (!ir()->start()->live_in().is_same(live_in_args)) {
829 #ifdef ASSERT
830 tty->print_cr("Error: live_in set of first block must be empty (when this fails, virtual registers are used before they are defined)");
831 tty->print_cr("affected registers:");
832 print_bitmap(ir()->start()->live_in());
833
834 // print some additional information to simplify debugging
835 for (unsigned int i = 0; i < ir()->start()->live_in().size(); i++) {
836 if (ir()->start()->live_in().at(i)) {
837 Instruction* instr = gen()->instruction_for_vreg(i);
838 tty->print_cr("* vreg %d (HIR instruction %c%d)", i, instr == nullptr ? ' ' : instr->type()->tchar(), instr == nullptr ? 0 : instr->id());
839
840 for (int j = 0; j < num_blocks; j++) {
841 BlockBegin* block = block_at(j);
842 if (block->live_gen().at(i)) {
843 tty->print_cr(" used in block B%d", block->block_id());
844 }
845 if (block->live_kill().at(i)) {
846 tty->print_cr(" defined in block B%d", block->block_id());
847 }
848 }
849 }
850 }
851
852 #endif
853 // when this fails, virtual registers are used before they are defined.
854 assert(false, "live_in set of first block must be empty");
855 // bailout of if this occurs in product mode.
856 bailout("live_in set of first block not empty");
857 }
858 }
859
860
861 // ********** Phase 4: build intervals
862 // (fills the list _intervals)
863
864 void LinearScan::add_use(Value value, int from, int to, IntervalUseKind use_kind) {
865 assert(!value->type()->is_illegal(), "if this value is used by the interpreter it shouldn't be of indeterminate type");
866 LIR_Opr opr = value->operand();
867 Constant* con = value->as_Constant();
868
869 if ((con == nullptr || con->is_pinned()) && opr->is_register()) {
870 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
871 add_use(opr, from, to, use_kind);
872 }
873 }
874
875
876 void LinearScan::add_def(LIR_Opr opr, int def_pos, IntervalUseKind use_kind) {
877 TRACE_LINEAR_SCAN(2, tty->print(" def "); opr->print(tty); tty->print_cr(" def_pos %d (%d)", def_pos, use_kind));
878 assert(opr->is_register(), "should not be called otherwise");
879
880 if (opr->is_virtual_register()) {
881 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
882 add_def(opr->vreg_number(), def_pos, use_kind, opr->type_register());
883
884 } else {
885 int reg = reg_num(opr);
886 if (is_processed_reg_num(reg)) {
887 add_def(reg, def_pos, use_kind, opr->type_register());
888 }
889 reg = reg_numHi(opr);
890 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
891 add_def(reg, def_pos, use_kind, opr->type_register());
892 }
893 }
894 }
895
896 void LinearScan::add_use(LIR_Opr opr, int from, int to, IntervalUseKind use_kind) {
897 TRACE_LINEAR_SCAN(2, tty->print(" use "); opr->print(tty); tty->print_cr(" from %d to %d (%d)", from, to, use_kind));
898 assert(opr->is_register(), "should not be called otherwise");
899
900 if (opr->is_virtual_register()) {
901 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
902 add_use(opr->vreg_number(), from, to, use_kind, opr->type_register());
903
904 } else {
905 int reg = reg_num(opr);
906 if (is_processed_reg_num(reg)) {
907 add_use(reg, from, to, use_kind, opr->type_register());
908 }
909 reg = reg_numHi(opr);
910 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
911 add_use(reg, from, to, use_kind, opr->type_register());
912 }
913 }
914 }
915
916 void LinearScan::add_temp(LIR_Opr opr, int temp_pos, IntervalUseKind use_kind) {
917 TRACE_LINEAR_SCAN(2, tty->print(" temp "); opr->print(tty); tty->print_cr(" temp_pos %d (%d)", temp_pos, use_kind));
918 assert(opr->is_register(), "should not be called otherwise");
919
920 if (opr->is_virtual_register()) {
921 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
922 add_temp(opr->vreg_number(), temp_pos, use_kind, opr->type_register());
923
924 } else {
925 int reg = reg_num(opr);
926 if (is_processed_reg_num(reg)) {
927 add_temp(reg, temp_pos, use_kind, opr->type_register());
928 }
929 reg = reg_numHi(opr);
930 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
931 add_temp(reg, temp_pos, use_kind, opr->type_register());
932 }
933 }
934 }
935
936
937 void LinearScan::add_def(int reg_num, int def_pos, IntervalUseKind use_kind, BasicType type) {
938 Interval* interval = interval_at(reg_num);
939 if (interval != nullptr) {
940 assert(interval->reg_num() == reg_num, "wrong interval");
941
942 if (type != T_ILLEGAL) {
943 interval->set_type(type);
944 }
945
946 Range* r = interval->first();
947 if (r->from() <= def_pos) {
948 // Update the starting point (when a range is first created for a use, its
949 // start is the beginning of the current block until a def is encountered.)
950 r->set_from(def_pos);
951 interval->add_use_pos(def_pos, use_kind);
952
953 } else {
954 // Dead value - make vacuous interval
955 // also add use_kind for dead intervals
956 interval->add_range(def_pos, def_pos + 1);
957 interval->add_use_pos(def_pos, use_kind);
958 TRACE_LINEAR_SCAN(2, tty->print_cr("Warning: def of reg %d at %d occurs without use", reg_num, def_pos));
959 }
960
961 } else {
962 // Dead value - make vacuous interval
963 // also add use_kind for dead intervals
964 interval = create_interval(reg_num);
965 if (type != T_ILLEGAL) {
966 interval->set_type(type);
967 }
968
969 interval->add_range(def_pos, def_pos + 1);
970 interval->add_use_pos(def_pos, use_kind);
971 TRACE_LINEAR_SCAN(2, tty->print_cr("Warning: dead value %d at %d in live intervals", reg_num, def_pos));
972 }
973
974 change_spill_definition_pos(interval, def_pos);
975 if (use_kind == noUse && interval->spill_state() <= startInMemory) {
976 // detection of method-parameters and roundfp-results
977 // TODO: move this directly to position where use-kind is computed
978 interval->set_spill_state(startInMemory);
979 }
980 }
981
982 void LinearScan::add_use(int reg_num, int from, int to, IntervalUseKind use_kind, BasicType type) {
983 Interval* interval = interval_at(reg_num);
984 if (interval == nullptr) {
985 interval = create_interval(reg_num);
986 }
987 assert(interval->reg_num() == reg_num, "wrong interval");
988
989 if (type != T_ILLEGAL) {
990 interval->set_type(type);
991 }
992
993 interval->add_range(from, to);
994 interval->add_use_pos(to, use_kind);
995 }
996
997 void LinearScan::add_temp(int reg_num, int temp_pos, IntervalUseKind use_kind, BasicType type) {
998 Interval* interval = interval_at(reg_num);
999 if (interval == nullptr) {
1000 interval = create_interval(reg_num);
1001 }
1002 assert(interval->reg_num() == reg_num, "wrong interval");
1003
1004 if (type != T_ILLEGAL) {
1005 interval->set_type(type);
1006 }
1007
1008 interval->add_range(temp_pos, temp_pos + 1);
1009 interval->add_use_pos(temp_pos, use_kind);
1010 }
1011
1012
1013 // the results of this functions are used for optimizing spilling and reloading
1014 // if the functions return shouldHaveRegister and the interval is spilled,
1015 // it is not reloaded to a register.
1016 IntervalUseKind LinearScan::use_kind_of_output_operand(LIR_Op* op, LIR_Opr opr) {
1017 if (op->code() == lir_move) {
1018 assert(op->as_Op1() != nullptr, "lir_move must be LIR_Op1");
1019 LIR_Op1* move = (LIR_Op1*)op;
1020 LIR_Opr res = move->result_opr();
1021 bool result_in_memory = res->is_virtual() && gen()->is_vreg_flag_set(res->vreg_number(), LIRGenerator::must_start_in_memory);
1022
1023 if (result_in_memory) {
1024 // Begin of an interval with must_start_in_memory set.
1025 // This interval will always get a stack slot first, so return noUse.
1026 return noUse;
1027
1028 } else if (move->in_opr()->is_stack()) {
1029 // method argument (condition must be equal to handle_method_arguments)
1030 return noUse;
1031
1032 } else if (move->in_opr()->is_register() && move->result_opr()->is_register()) {
1033 // Move from register to register
1034 if (block_of_op_with_id(op->id())->is_set(BlockBegin::osr_entry_flag)) {
1035 // special handling of phi-function moves inside osr-entry blocks
1036 // input operand must have a register instead of output operand (leads to better register allocation)
1037 return shouldHaveRegister;
1038 }
1039 }
1040 }
1041
1042 if (opr->is_virtual() &&
1043 gen()->is_vreg_flag_set(opr->vreg_number(), LIRGenerator::must_start_in_memory)) {
1044 // result is a stack-slot, so prevent immediate reloading
1045 return noUse;
1046 }
1047
1048 // all other operands require a register
1049 return mustHaveRegister;
1050 }
1051
1052 IntervalUseKind LinearScan::use_kind_of_input_operand(LIR_Op* op, LIR_Opr opr) {
1053 if (op->code() == lir_move) {
1054 assert(op->as_Op1() != nullptr, "lir_move must be LIR_Op1");
1055 LIR_Op1* move = (LIR_Op1*)op;
1056 LIR_Opr res = move->result_opr();
1057 bool result_in_memory = res->is_virtual() && gen()->is_vreg_flag_set(res->vreg_number(), LIRGenerator::must_start_in_memory);
1058
1059 if (result_in_memory) {
1060 // Move to an interval with must_start_in_memory set.
1061 // To avoid moves from stack to stack (not allowed) force the input operand to a register
1062 return mustHaveRegister;
1063
1064 } else if (move->in_opr()->is_register() && move->result_opr()->is_register()) {
1065 // Move from register to register
1066 if (block_of_op_with_id(op->id())->is_set(BlockBegin::osr_entry_flag)) {
1067 // special handling of phi-function moves inside osr-entry blocks
1068 // input operand must have a register instead of output operand (leads to better register allocation)
1069 return mustHaveRegister;
1070 }
1071
1072 // The input operand is not forced to a register (moves from stack to register are allowed),
1073 // but it is faster if the input operand is in a register
1074 return shouldHaveRegister;
1075 }
1076 }
1077
1078
1079 #if defined(X86) || defined(S390)
1080 if (op->code() == lir_cmove) {
1081 // conditional moves can handle stack operands
1082 assert(op->result_opr()->is_register(), "result must always be in a register");
1083 return shouldHaveRegister;
1084 }
1085
1086 // optimizations for second input operand of arithmehtic operations on Intel
1087 // this operand is allowed to be on the stack in some cases
1088 BasicType opr_type = opr->type_register();
1089 if (opr_type == T_FLOAT || opr_type == T_DOUBLE) {
1090 if (IA32_ONLY( (UseSSE == 1 && opr_type == T_FLOAT) || UseSSE >= 2 ) NOT_IA32( true )) {
1091 // SSE float instruction (T_DOUBLE only supported with SSE2)
1092 switch (op->code()) {
1093 case lir_cmp:
1094 case lir_add:
1095 case lir_sub:
1096 case lir_mul:
1097 case lir_div:
1098 {
1099 assert(op->as_Op2() != nullptr, "must be LIR_Op2");
1100 LIR_Op2* op2 = (LIR_Op2*)op;
1101 if (op2->in_opr1() != op2->in_opr2() && op2->in_opr2() == opr) {
1102 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");
1103 return shouldHaveRegister;
1104 }
1105 }
1106 default:
1107 break;
1108 }
1109 } else {
1110 // FPU stack float instruction
1111 switch (op->code()) {
1112 case lir_add:
1113 case lir_sub:
1114 case lir_mul:
1115 case lir_div:
1116 {
1117 assert(op->as_Op2() != nullptr, "must be LIR_Op2");
1118 LIR_Op2* op2 = (LIR_Op2*)op;
1119 if (op2->in_opr1() != op2->in_opr2() && op2->in_opr2() == opr) {
1120 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");
1121 return shouldHaveRegister;
1122 }
1123 }
1124 default:
1125 break;
1126 }
1127 }
1128 // We want to sometimes use logical operations on pointers, in particular in GC barriers.
1129 // Since 64bit logical operations do not current support operands on stack, we have to make sure
1130 // T_OBJECT doesn't get spilled along with T_LONG.
1131 } else if (opr_type != T_LONG LP64_ONLY(&& opr_type != T_OBJECT)) {
1132 // integer instruction (note: long operands must always be in register)
1133 switch (op->code()) {
1134 case lir_cmp:
1135 case lir_add:
1136 case lir_sub:
1137 case lir_logic_and:
1138 case lir_logic_or:
1139 case lir_logic_xor:
1140 {
1141 assert(op->as_Op2() != nullptr, "must be LIR_Op2");
1142 LIR_Op2* op2 = (LIR_Op2*)op;
1143 if (op2->in_opr1() != op2->in_opr2() && op2->in_opr2() == opr) {
1144 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");
1145 return shouldHaveRegister;
1146 }
1147 }
1148 default:
1149 break;
1150 }
1151 }
1152 #endif // X86 || S390
1153
1154 // all other operands require a register
1155 return mustHaveRegister;
1156 }
1157
1158
1159 void LinearScan::handle_method_arguments(LIR_Op* op) {
1160 // special handling for method arguments (moves from stack to virtual register):
1161 // the interval gets no register assigned, but the stack slot.
1162 // it is split before the first use by the register allocator.
1163
1164 if (op->code() == lir_move) {
1165 assert(op->as_Op1() != nullptr, "must be LIR_Op1");
1166 LIR_Op1* move = (LIR_Op1*)op;
1167
1168 if (move->in_opr()->is_stack()) {
1169 #ifdef ASSERT
1170 int arg_size = compilation()->method()->arg_size();
1171 LIR_Opr o = move->in_opr();
1172 if (o->is_single_stack()) {
1173 assert(o->single_stack_ix() >= 0 && o->single_stack_ix() < arg_size, "out of range");
1174 } else if (o->is_double_stack()) {
1175 assert(o->double_stack_ix() >= 0 && o->double_stack_ix() < arg_size, "out of range");
1176 } else {
1177 ShouldNotReachHere();
1178 }
1179
1180 assert(move->id() > 0, "invalid id");
1181 assert(block_of_op_with_id(move->id())->number_of_preds() == 0, "move from stack must be in first block");
1182 assert(move->result_opr()->is_virtual(), "result of move must be a virtual register");
1183
1184 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())));
1185 #endif
1186
1187 Interval* interval = interval_at(reg_num(move->result_opr()));
1188
1189 int stack_slot = LinearScan::nof_regs + (move->in_opr()->is_single_stack() ? move->in_opr()->single_stack_ix() : move->in_opr()->double_stack_ix());
1190 interval->set_canonical_spill_slot(stack_slot);
1191 interval->assign_reg(stack_slot);
1192 }
1193 }
1194 }
1195
1196 void LinearScan::handle_doubleword_moves(LIR_Op* op) {
1197 // special handling for doubleword move from memory to register:
1198 // in this case the registers of the input address and the result
1199 // registers must not overlap -> add a temp range for the input registers
1200 if (op->code() == lir_move) {
1201 assert(op->as_Op1() != nullptr, "must be LIR_Op1");
1202 LIR_Op1* move = (LIR_Op1*)op;
1203
1204 if (move->result_opr()->is_double_cpu() && move->in_opr()->is_pointer()) {
1205 LIR_Address* address = move->in_opr()->as_address_ptr();
1206 if (address != nullptr) {
1207 if (address->base()->is_valid()) {
1208 add_temp(address->base(), op->id(), noUse);
1209 }
1210 if (address->index()->is_valid()) {
1211 add_temp(address->index(), op->id(), noUse);
1212 }
1213 }
1214 }
1215 }
1216 }
1217
1218 void LinearScan::add_register_hints(LIR_Op* op) {
1219 switch (op->code()) {
1220 case lir_move: // fall through
1221 case lir_convert: {
1222 assert(op->as_Op1() != nullptr, "lir_move, lir_convert must be LIR_Op1");
1223 LIR_Op1* move = (LIR_Op1*)op;
1224
1225 LIR_Opr move_from = move->in_opr();
1226 LIR_Opr move_to = move->result_opr();
1227
1228 if (move_to->is_register() && move_from->is_register()) {
1229 Interval* from = interval_at(reg_num(move_from));
1230 Interval* to = interval_at(reg_num(move_to));
1231 if (from != nullptr && to != nullptr) {
1232 to->set_register_hint(from);
1233 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()));
1234 }
1235 }
1236 break;
1237 }
1238 case lir_cmove: {
1239 assert(op->as_Op4() != nullptr, "lir_cmove must be LIR_Op4");
1240 LIR_Op4* cmove = (LIR_Op4*)op;
1241
1242 LIR_Opr move_from = cmove->in_opr1();
1243 LIR_Opr move_to = cmove->result_opr();
1244
1245 if (move_to->is_register() && move_from->is_register()) {
1246 Interval* from = interval_at(reg_num(move_from));
1247 Interval* to = interval_at(reg_num(move_to));
1248 if (from != nullptr && to != nullptr) {
1249 to->set_register_hint(from);
1250 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()));
1251 }
1252 }
1253 break;
1254 }
1255 default:
1256 break;
1257 }
1258 }
1259
1260
1261 void LinearScan::build_intervals() {
1262 TIME_LINEAR_SCAN(timer_build_intervals);
1263
1264 // initialize interval list with expected number of intervals
1265 // (32 is added to have some space for split children without having to resize the list)
1266 _intervals = IntervalList(num_virtual_regs() + 32);
1267 // initialize all slots that are used by build_intervals
1268 _intervals.at_put_grow(num_virtual_regs() - 1, nullptr, nullptr);
1269
1270 // create a list with all caller-save registers (cpu, fpu, xmm)
1271 // when an instruction is a call, a temp range is created for all these registers
1272 int num_caller_save_registers = 0;
1273 int caller_save_registers[LinearScan::nof_regs];
1274
1275 int i;
1276 for (i = 0; i < FrameMap::nof_caller_save_cpu_regs(); i++) {
1277 LIR_Opr opr = FrameMap::caller_save_cpu_reg_at(i);
1278 assert(opr->is_valid() && opr->is_register(), "FrameMap should not return invalid operands");
1279 assert(reg_numHi(opr) == -1, "missing addition of range for hi-register");
1280 caller_save_registers[num_caller_save_registers++] = reg_num(opr);
1281 }
1282
1283 // temp ranges for fpu registers are only created when the method has
1284 // virtual fpu operands. Otherwise no allocation for fpu registers is
1285 // performed and so the temp ranges would be useless
1286 if (has_fpu_registers()) {
1287 #ifdef X86
1288 if (UseSSE < 2) {
1289 #endif // X86
1290 for (i = 0; i < FrameMap::nof_caller_save_fpu_regs; i++) {
1291 LIR_Opr opr = FrameMap::caller_save_fpu_reg_at(i);
1292 assert(opr->is_valid() && opr->is_register(), "FrameMap should not return invalid operands");
1293 assert(reg_numHi(opr) == -1, "missing addition of range for hi-register");
1294 caller_save_registers[num_caller_save_registers++] = reg_num(opr);
1295 }
1296 #ifdef X86
1297 }
1298 #endif // X86
1299
1300 #ifdef X86
1301 if (UseSSE > 0) {
1302 int num_caller_save_xmm_regs = FrameMap::get_num_caller_save_xmms();
1303 for (i = 0; i < num_caller_save_xmm_regs; i ++) {
1304 LIR_Opr opr = FrameMap::caller_save_xmm_reg_at(i);
1305 assert(opr->is_valid() && opr->is_register(), "FrameMap should not return invalid operands");
1306 assert(reg_numHi(opr) == -1, "missing addition of range for hi-register");
1307 caller_save_registers[num_caller_save_registers++] = reg_num(opr);
1308 }
1309 }
1310 #endif // X86
1311 }
1312 assert(num_caller_save_registers <= LinearScan::nof_regs, "out of bounds");
1313
1314
1315 LIR_OpVisitState visitor;
1316
1317 // iterate all blocks in reverse order
1318 for (i = block_count() - 1; i >= 0; i--) {
1319 BlockBegin* block = block_at(i);
1320 LIR_OpList* instructions = block->lir()->instructions_list();
1321 int block_from = block->first_lir_instruction_id();
1322 int block_to = block->last_lir_instruction_id();
1323
1324 assert(block_from == instructions->at(0)->id(), "must be");
1325 assert(block_to == instructions->at(instructions->length() - 1)->id(), "must be");
1326
1327 // Update intervals for registers live at the end of this block;
1328 ResourceBitMap& live = block->live_out();
1329 auto updater = [&](BitMap::idx_t index) {
1330 int number = static_cast<int>(index);
1331 assert(number >= LIR_Opr::vreg_base, "fixed intervals must not be live on block bounds");
1332 TRACE_LINEAR_SCAN(2, tty->print_cr("live in %d to %d", number, block_to + 2));
1333
1334 add_use(number, block_from, block_to + 2, noUse, T_ILLEGAL);
1335
1336 // add special use positions for loop-end blocks when the
1337 // interval is used anywhere inside this loop. It's possible
1338 // that the block was part of a non-natural loop, so it might
1339 // have an invalid loop index.
1340 if (block->is_set(BlockBegin::linear_scan_loop_end_flag) &&
1341 block->loop_index() != -1 &&
1342 is_interval_in_loop(number, block->loop_index())) {
1343 interval_at(number)->add_use_pos(block_to + 1, loopEndMarker);
1344 }
1345 };
1346 live.iterate(updater);
1347
1348 // iterate all instructions of the block in reverse order.
1349 // skip the first instruction because it is always a label
1350 // definitions of intervals are processed before uses
1351 assert(visitor.no_operands(instructions->at(0)), "first operation must always be a label");
1352 for (int j = instructions->length() - 1; j >= 1; j--) {
1353 LIR_Op* op = instructions->at(j);
1354 int op_id = op->id();
1355
1356 // visit operation to collect all operands
1357 visitor.visit(op);
1358
1359 // add a temp range for each register if operation destroys caller-save registers
1360 if (visitor.has_call()) {
1361 for (int k = 0; k < num_caller_save_registers; k++) {
1362 add_temp(caller_save_registers[k], op_id, noUse, T_ILLEGAL);
1363 }
1364 TRACE_LINEAR_SCAN(4, tty->print_cr("operation destroys all caller-save registers"));
1365 }
1366
1367 // Add any platform dependent temps
1368 pd_add_temps(op);
1369
1370 // visit definitions (output and temp operands)
1371 int k, n;
1372 n = visitor.opr_count(LIR_OpVisitState::outputMode);
1373 for (k = 0; k < n; k++) {
1374 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::outputMode, k);
1375 assert(opr->is_register(), "visitor should only return register operands");
1376 add_def(opr, op_id, use_kind_of_output_operand(op, opr));
1377 }
1378
1379 n = visitor.opr_count(LIR_OpVisitState::tempMode);
1380 for (k = 0; k < n; k++) {
1381 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::tempMode, k);
1382 assert(opr->is_register(), "visitor should only return register operands");
1383 add_temp(opr, op_id, mustHaveRegister);
1384 }
1385
1386 // visit uses (input operands)
1387 n = visitor.opr_count(LIR_OpVisitState::inputMode);
1388 for (k = 0; k < n; k++) {
1389 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::inputMode, k);
1390 assert(opr->is_register(), "visitor should only return register operands");
1391 add_use(opr, block_from, op_id, use_kind_of_input_operand(op, opr));
1392 }
1393
1394 // Add uses of live locals from interpreter's point of view for proper
1395 // debug information generation
1396 // Treat these operands as temp values (if the life range is extended
1397 // to a call site, the value would be in a register at the call otherwise)
1398 n = visitor.info_count();
1399 for (k = 0; k < n; k++) {
1400 CodeEmitInfo* info = visitor.info_at(k);
1401 ValueStack* stack = info->stack();
1402 for_each_state_value(stack, value,
1403 add_use(value, block_from, op_id + 1, noUse);
1404 );
1405 }
1406
1407 // special steps for some instructions (especially moves)
1408 handle_method_arguments(op);
1409 handle_doubleword_moves(op);
1410 add_register_hints(op);
1411
1412 } // end of instruction iteration
1413 } // end of block iteration
1414
1415
1416 // add the range [0, 1[ to all fixed intervals
1417 // -> the register allocator need not handle unhandled fixed intervals
1418 for (int n = 0; n < LinearScan::nof_regs; n++) {
1419 Interval* interval = interval_at(n);
1420 if (interval != nullptr) {
1421 interval->add_range(0, 1);
1422 }
1423 }
1424 }
1425
1426
1427 // ********** Phase 5: actual register allocation
1428
1429 int LinearScan::interval_cmp(Interval** a, Interval** b) {
1430 if (*a != nullptr) {
1431 if (*b != nullptr) {
1432 return (*a)->from() - (*b)->from();
1433 } else {
1434 return -1;
1435 }
1436 } else {
1437 if (*b != nullptr) {
1438 return 1;
1439 } else {
1440 return 0;
1441 }
1442 }
1443 }
1444
1445 #ifdef ASSERT
1446 static int interval_cmp(Interval* const& l, Interval* const& r) {
1447 return l->from() - r->from();
1448 }
1449
1450 static bool find_interval(Interval* interval, IntervalArray* intervals) {
1451 bool found;
1452 int idx = intervals->find_sorted<Interval*, interval_cmp>(interval, found);
1453
1454 if (!found) {
1455 return false;
1456 }
1457
1458 int from = interval->from();
1459
1460 // The index we've found using binary search is pointing to an interval
1461 // that is defined in the same place as the interval we were looking for.
1462 // So now we have to look around that index and find exact interval.
1463 for (int i = idx; i >= 0; i--) {
1464 if (intervals->at(i) == interval) {
1465 return true;
1466 }
1467 if (intervals->at(i)->from() != from) {
1468 break;
1469 }
1470 }
1471
1472 for (int i = idx + 1; i < intervals->length(); i++) {
1473 if (intervals->at(i) == interval) {
1474 return true;
1475 }
1476 if (intervals->at(i)->from() != from) {
1477 break;
1478 }
1479 }
1480
1481 return false;
1482 }
1483
1484 bool LinearScan::is_sorted(IntervalArray* intervals) {
1485 int from = -1;
1486 int null_count = 0;
1487
1488 for (int i = 0; i < intervals->length(); i++) {
1489 Interval* it = intervals->at(i);
1490 if (it != nullptr) {
1491 assert(from <= it->from(), "Intervals are unordered");
1492 from = it->from();
1493 } else {
1494 null_count++;
1495 }
1496 }
1497
1498 assert(null_count == 0, "Sorted intervals should not contain nulls");
1499
1500 null_count = 0;
1501
1502 for (int i = 0; i < interval_count(); i++) {
1503 Interval* interval = interval_at(i);
1504 if (interval != nullptr) {
1505 assert(find_interval(interval, intervals), "Lists do not contain same intervals");
1506 } else {
1507 null_count++;
1508 }
1509 }
1510
1511 assert(interval_count() - null_count == intervals->length(),
1512 "Sorted list should contain the same amount of non-null intervals as unsorted list");
1513
1514 return true;
1515 }
1516 #endif
1517
1518 void LinearScan::add_to_list(Interval** first, Interval** prev, Interval* interval) {
1519 if (*prev != nullptr) {
1520 (*prev)->set_next(interval);
1521 } else {
1522 *first = interval;
1523 }
1524 *prev = interval;
1525 }
1526
1527 void LinearScan::create_unhandled_lists(Interval** list1, Interval** list2, bool (is_list1)(const Interval* i), bool (is_list2)(const Interval* i)) {
1528 assert(is_sorted(_sorted_intervals), "interval list is not sorted");
1529
1530 *list1 = *list2 = Interval::end();
1531
1532 Interval* list1_prev = nullptr;
1533 Interval* list2_prev = nullptr;
1534 Interval* v;
1535
1536 const int n = _sorted_intervals->length();
1537 for (int i = 0; i < n; i++) {
1538 v = _sorted_intervals->at(i);
1539 if (v == nullptr) continue;
1540
1541 if (is_list1(v)) {
1542 add_to_list(list1, &list1_prev, v);
1543 } else if (is_list2 == nullptr || is_list2(v)) {
1544 add_to_list(list2, &list2_prev, v);
1545 }
1546 }
1547
1548 if (list1_prev != nullptr) list1_prev->set_next(Interval::end());
1549 if (list2_prev != nullptr) list2_prev->set_next(Interval::end());
1550
1551 assert(list1_prev == nullptr || list1_prev->next() == Interval::end(), "linear list ends not with sentinel");
1552 assert(list2_prev == nullptr || list2_prev->next() == Interval::end(), "linear list ends not with sentinel");
1553 }
1554
1555
1556 void LinearScan::sort_intervals_before_allocation() {
1557 TIME_LINEAR_SCAN(timer_sort_intervals_before);
1558
1559 if (_needs_full_resort) {
1560 // There is no known reason why this should occur but just in case...
1561 assert(false, "should never occur");
1562 // Re-sort existing interval list because an Interval::from() has changed
1563 _sorted_intervals->sort(interval_cmp);
1564 _needs_full_resort = false;
1565 }
1566
1567 IntervalList* unsorted_list = &_intervals;
1568 int unsorted_len = unsorted_list->length();
1569 int sorted_len = 0;
1570 int unsorted_idx;
1571 int sorted_idx = 0;
1572 int sorted_from_max = -1;
1573
1574 // calc number of items for sorted list (sorted list must not contain null values)
1575 for (unsorted_idx = 0; unsorted_idx < unsorted_len; unsorted_idx++) {
1576 if (unsorted_list->at(unsorted_idx) != nullptr) {
1577 sorted_len++;
1578 }
1579 }
1580 IntervalArray* sorted_list = new IntervalArray(sorted_len, sorted_len, nullptr);
1581
1582 // special sorting algorithm: the original interval-list is almost sorted,
1583 // only some intervals are swapped. So this is much faster than a complete QuickSort
1584 for (unsorted_idx = 0; unsorted_idx < unsorted_len; unsorted_idx++) {
1585 Interval* cur_interval = unsorted_list->at(unsorted_idx);
1586
1587 if (cur_interval != nullptr) {
1588 int cur_from = cur_interval->from();
1589
1590 if (sorted_from_max <= cur_from) {
1591 sorted_list->at_put(sorted_idx++, cur_interval);
1592 sorted_from_max = cur_interval->from();
1593 } else {
1594 // the assumption that the intervals are already sorted failed,
1595 // so this interval must be sorted in manually
1596 int j;
1597 for (j = sorted_idx - 1; j >= 0 && cur_from < sorted_list->at(j)->from(); j--) {
1598 sorted_list->at_put(j + 1, sorted_list->at(j));
1599 }
1600 sorted_list->at_put(j + 1, cur_interval);
1601 sorted_idx++;
1602 }
1603 }
1604 }
1605 _sorted_intervals = sorted_list;
1606 assert(is_sorted(_sorted_intervals), "intervals unsorted");
1607 }
1608
1609 void LinearScan::sort_intervals_after_allocation() {
1610 TIME_LINEAR_SCAN(timer_sort_intervals_after);
1611
1612 if (_needs_full_resort) {
1613 // Re-sort existing interval list because an Interval::from() has changed
1614 _sorted_intervals->sort(interval_cmp);
1615 _needs_full_resort = false;
1616 }
1617
1618 IntervalArray* old_list = _sorted_intervals;
1619 IntervalList* new_list = _new_intervals_from_allocation;
1620 int old_len = old_list->length();
1621 int new_len = new_list == nullptr ? 0 : new_list->length();
1622
1623 if (new_len == 0) {
1624 // no intervals have been added during allocation, so sorted list is already up to date
1625 assert(is_sorted(_sorted_intervals), "intervals unsorted");
1626 return;
1627 }
1628
1629 // conventional sort-algorithm for new intervals
1630 new_list->sort(interval_cmp);
1631
1632 // merge old and new list (both already sorted) into one combined list
1633 int combined_list_len = old_len + new_len;
1634 IntervalArray* combined_list = new IntervalArray(combined_list_len, combined_list_len, nullptr);
1635 int old_idx = 0;
1636 int new_idx = 0;
1637
1638 while (old_idx + new_idx < old_len + new_len) {
1639 if (new_idx >= new_len || (old_idx < old_len && old_list->at(old_idx)->from() <= new_list->at(new_idx)->from())) {
1640 combined_list->at_put(old_idx + new_idx, old_list->at(old_idx));
1641 old_idx++;
1642 } else {
1643 combined_list->at_put(old_idx + new_idx, new_list->at(new_idx));
1644 new_idx++;
1645 }
1646 }
1647
1648 _sorted_intervals = combined_list;
1649 assert(is_sorted(_sorted_intervals), "intervals unsorted");
1650 }
1651
1652
1653 void LinearScan::allocate_registers() {
1654 TIME_LINEAR_SCAN(timer_allocate_registers);
1655
1656 Interval* precolored_cpu_intervals, *not_precolored_cpu_intervals;
1657 Interval* precolored_fpu_intervals, *not_precolored_fpu_intervals;
1658
1659 // collect cpu intervals
1660 create_unhandled_lists(&precolored_cpu_intervals, ¬_precolored_cpu_intervals,
1661 is_precolored_cpu_interval, is_virtual_cpu_interval);
1662
1663 // collect fpu intervals
1664 create_unhandled_lists(&precolored_fpu_intervals, ¬_precolored_fpu_intervals,
1665 is_precolored_fpu_interval, is_virtual_fpu_interval);
1666 // this fpu interval collection cannot be moved down below with the allocation section as
1667 // the cpu_lsw.walk() changes interval positions.
1668
1669 if (!has_fpu_registers()) {
1670 #ifdef ASSERT
1671 assert(not_precolored_fpu_intervals == Interval::end(), "missed an uncolored fpu interval");
1672 #else
1673 if (not_precolored_fpu_intervals != Interval::end()) {
1674 BAILOUT("missed an uncolored fpu interval");
1675 }
1676 #endif
1677 }
1678
1679 // allocate cpu registers
1680 LinearScanWalker cpu_lsw(this, precolored_cpu_intervals, not_precolored_cpu_intervals);
1681 cpu_lsw.walk();
1682 cpu_lsw.finish_allocation();
1683
1684 if (has_fpu_registers()) {
1685 // allocate fpu registers
1686 LinearScanWalker fpu_lsw(this, precolored_fpu_intervals, not_precolored_fpu_intervals);
1687 fpu_lsw.walk();
1688 fpu_lsw.finish_allocation();
1689 }
1690 }
1691
1692
1693 // ********** Phase 6: resolve data flow
1694 // (insert moves at edges between blocks if intervals have been split)
1695
1696 // wrapper for Interval::split_child_at_op_id that performs a bailout in product mode
1697 // instead of returning null
1698 Interval* LinearScan::split_child_at_op_id(Interval* interval, int op_id, LIR_OpVisitState::OprMode mode) {
1699 Interval* result = interval->split_child_at_op_id(op_id, mode);
1700 if (result != nullptr) {
1701 return result;
1702 }
1703
1704 assert(false, "must find an interval, but do a clean bailout in product mode");
1705 result = new Interval(LIR_Opr::vreg_base);
1706 result->assign_reg(0);
1707 result->set_type(T_INT);
1708 BAILOUT_("LinearScan: interval is null", result);
1709 }
1710
1711
1712 Interval* LinearScan::interval_at_block_begin(BlockBegin* block, int reg_num) {
1713 assert(LinearScan::nof_regs <= reg_num && reg_num < num_virtual_regs(), "register number out of bounds");
1714 assert(interval_at(reg_num) != nullptr, "no interval found");
1715
1716 return split_child_at_op_id(interval_at(reg_num), block->first_lir_instruction_id(), LIR_OpVisitState::outputMode);
1717 }
1718
1719 Interval* LinearScan::interval_at_block_end(BlockBegin* block, int reg_num) {
1720 assert(LinearScan::nof_regs <= reg_num && reg_num < num_virtual_regs(), "register number out of bounds");
1721 assert(interval_at(reg_num) != nullptr, "no interval found");
1722
1723 return split_child_at_op_id(interval_at(reg_num), block->last_lir_instruction_id() + 1, LIR_OpVisitState::outputMode);
1724 }
1725
1726 Interval* LinearScan::interval_at_op_id(int reg_num, int op_id) {
1727 assert(LinearScan::nof_regs <= reg_num && reg_num < num_virtual_regs(), "register number out of bounds");
1728 assert(interval_at(reg_num) != nullptr, "no interval found");
1729
1730 return split_child_at_op_id(interval_at(reg_num), op_id, LIR_OpVisitState::inputMode);
1731 }
1732
1733
1734 void LinearScan::resolve_collect_mappings(BlockBegin* from_block, BlockBegin* to_block, MoveResolver &move_resolver) {
1735 DEBUG_ONLY(move_resolver.check_empty());
1736
1737 // visit all registers where the live_at_edge bit is set
1738 const ResourceBitMap& live_at_edge = to_block->live_in();
1739 auto visitor = [&](BitMap::idx_t index) {
1740 int r = static_cast<int>(index);
1741 assert(r < num_virtual_regs(), "live information set for not existing interval");
1742 assert(from_block->live_out().at(r) && to_block->live_in().at(r), "interval not live at this edge");
1743
1744 Interval* from_interval = interval_at_block_end(from_block, r);
1745 Interval* to_interval = interval_at_block_begin(to_block, r);
1746
1747 if (from_interval != to_interval && (from_interval->assigned_reg() != to_interval->assigned_reg() || from_interval->assigned_regHi() != to_interval->assigned_regHi())) {
1748 // need to insert move instruction
1749 move_resolver.add_mapping(from_interval, to_interval);
1750 }
1751 };
1752 live_at_edge.iterate(visitor, 0, live_set_size());
1753 }
1754
1755
1756 void LinearScan::resolve_find_insert_pos(BlockBegin* from_block, BlockBegin* to_block, MoveResolver &move_resolver) {
1757 if (from_block->number_of_sux() <= 1) {
1758 TRACE_LINEAR_SCAN(4, tty->print_cr("inserting moves at end of from_block B%d", from_block->block_id()));
1759
1760 LIR_OpList* instructions = from_block->lir()->instructions_list();
1761 LIR_OpBranch* branch = instructions->last()->as_OpBranch();
1762 if (branch != nullptr) {
1763 // insert moves before branch
1764 assert(branch->cond() == lir_cond_always, "block does not end with an unconditional jump");
1765 move_resolver.set_insert_position(from_block->lir(), instructions->length() - 2);
1766 } else {
1767 move_resolver.set_insert_position(from_block->lir(), instructions->length() - 1);
1768 }
1769
1770 } else {
1771 TRACE_LINEAR_SCAN(4, tty->print_cr("inserting moves at beginning of to_block B%d", to_block->block_id()));
1772 #ifdef ASSERT
1773 assert(from_block->lir()->instructions_list()->at(0)->as_OpLabel() != nullptr, "block does not start with a label");
1774
1775 // because the number of predecessor edges matches the number of
1776 // successor edges, blocks which are reached by switch statements
1777 // may have be more than one predecessor but it will be guaranteed
1778 // that all predecessors will be the same.
1779 for (int i = 0; i < to_block->number_of_preds(); i++) {
1780 assert(from_block == to_block->pred_at(i), "all critical edges must be broken");
1781 }
1782 #endif
1783
1784 move_resolver.set_insert_position(to_block->lir(), 0);
1785 }
1786 }
1787
1788
1789 // insert necessary moves (spilling or reloading) at edges between blocks if interval has been split
1790 void LinearScan::resolve_data_flow() {
1791 TIME_LINEAR_SCAN(timer_resolve_data_flow);
1792
1793 int num_blocks = block_count();
1794 MoveResolver move_resolver(this);
1795 ResourceBitMap block_completed(num_blocks);
1796 ResourceBitMap already_resolved(num_blocks);
1797
1798 int i;
1799 for (i = 0; i < num_blocks; i++) {
1800 BlockBegin* block = block_at(i);
1801
1802 // check if block has only one predecessor and only one successor
1803 if (block->number_of_preds() == 1 && block->number_of_sux() == 1 && block->number_of_exception_handlers() == 0) {
1804 LIR_OpList* instructions = block->lir()->instructions_list();
1805 assert(instructions->at(0)->code() == lir_label, "block must start with label");
1806 assert(instructions->last()->code() == lir_branch, "block with successors must end with branch");
1807 assert(instructions->last()->as_OpBranch()->cond() == lir_cond_always, "block with successor must end with unconditional branch");
1808
1809 // check if block is empty (only label and branch)
1810 if (instructions->length() == 2) {
1811 BlockBegin* pred = block->pred_at(0);
1812 BlockBegin* sux = block->sux_at(0);
1813
1814 // prevent optimization of two consecutive blocks
1815 if (!block_completed.at(pred->linear_scan_number()) && !block_completed.at(sux->linear_scan_number())) {
1816 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()));
1817 block_completed.set_bit(block->linear_scan_number());
1818
1819 // directly resolve between pred and sux (without looking at the empty block between)
1820 resolve_collect_mappings(pred, sux, move_resolver);
1821 if (move_resolver.has_mappings()) {
1822 move_resolver.set_insert_position(block->lir(), 0);
1823 move_resolver.resolve_and_append_moves();
1824 }
1825 }
1826 }
1827 }
1828 }
1829
1830
1831 for (i = 0; i < num_blocks; i++) {
1832 if (!block_completed.at(i)) {
1833 BlockBegin* from_block = block_at(i);
1834 already_resolved.set_from(block_completed);
1835
1836 int num_sux = from_block->number_of_sux();
1837 for (int s = 0; s < num_sux; s++) {
1838 BlockBegin* to_block = from_block->sux_at(s);
1839
1840 // check for duplicate edges between the same blocks (can happen with switch blocks)
1841 if (!already_resolved.at(to_block->linear_scan_number())) {
1842 TRACE_LINEAR_SCAN(3, tty->print_cr("**** processing edge between B%d and B%d", from_block->block_id(), to_block->block_id()));
1843 already_resolved.set_bit(to_block->linear_scan_number());
1844
1845 // collect all intervals that have been split between from_block and to_block
1846 resolve_collect_mappings(from_block, to_block, move_resolver);
1847 if (move_resolver.has_mappings()) {
1848 resolve_find_insert_pos(from_block, to_block, move_resolver);
1849 move_resolver.resolve_and_append_moves();
1850 }
1851 }
1852 }
1853 }
1854 }
1855 }
1856
1857
1858 void LinearScan::resolve_exception_entry(BlockBegin* block, int reg_num, MoveResolver &move_resolver) {
1859 if (interval_at(reg_num) == nullptr) {
1860 // if a phi function is never used, no interval is created -> ignore this
1861 return;
1862 }
1863
1864 Interval* interval = interval_at_block_begin(block, reg_num);
1865 int reg = interval->assigned_reg();
1866 int regHi = interval->assigned_regHi();
1867
1868 if ((reg < nof_regs && interval->always_in_memory())) {
1869 // the interval is split to get a short range that is located on the stack
1870 // in the following case:
1871 // * the interval started in memory (e.g. method parameter), but is currently in a register
1872 // this is an optimization for exception handling that reduces the number of moves that
1873 // are necessary for resolving the states when an exception uses this exception handler
1874
1875 // range that will be spilled to memory
1876 int from_op_id = block->first_lir_instruction_id();
1877 int to_op_id = from_op_id + 1; // short live range of length 1
1878 assert(interval->from() <= from_op_id && interval->to() >= to_op_id,
1879 "no split allowed between exception entry and first instruction");
1880
1881 if (interval->from() != from_op_id) {
1882 // the part before from_op_id is unchanged
1883 interval = interval->split(from_op_id);
1884 interval->assign_reg(reg, regHi);
1885 append_interval(interval);
1886 } else {
1887 _needs_full_resort = true;
1888 }
1889 assert(interval->from() == from_op_id, "must be true now");
1890
1891 Interval* spilled_part = interval;
1892 if (interval->to() != to_op_id) {
1893 // the part after to_op_id is unchanged
1894 spilled_part = interval->split_from_start(to_op_id);
1895 append_interval(spilled_part);
1896 move_resolver.add_mapping(spilled_part, interval);
1897 }
1898 assign_spill_slot(spilled_part);
1899
1900 assert(spilled_part->from() == from_op_id && spilled_part->to() == to_op_id, "just checking");
1901 }
1902 }
1903
1904 void LinearScan::resolve_exception_entry(BlockBegin* block, MoveResolver &move_resolver) {
1905 assert(block->is_set(BlockBegin::exception_entry_flag), "should not call otherwise");
1906 DEBUG_ONLY(move_resolver.check_empty());
1907
1908 // visit all registers where the live_in bit is set
1909 auto resolver = [&](BitMap::idx_t index) {
1910 int r = static_cast<int>(index);
1911 resolve_exception_entry(block, r, move_resolver);
1912 };
1913 block->live_in().iterate(resolver, 0, live_set_size());
1914
1915 // the live_in bits are not set for phi functions of the xhandler entry, so iterate them separately
1916 for_each_phi_fun(block, phi,
1917 if (!phi->is_illegal()) { resolve_exception_entry(block, phi->operand()->vreg_number(), move_resolver); }
1918 );
1919
1920 if (move_resolver.has_mappings()) {
1921 // insert moves after first instruction
1922 move_resolver.set_insert_position(block->lir(), 0);
1923 move_resolver.resolve_and_append_moves();
1924 }
1925 }
1926
1927
1928 void LinearScan::resolve_exception_edge(XHandler* handler, int throwing_op_id, int reg_num, Phi* phi, MoveResolver &move_resolver) {
1929 if (interval_at(reg_num) == nullptr) {
1930 // if a phi function is never used, no interval is created -> ignore this
1931 return;
1932 }
1933
1934 // the computation of to_interval is equal to resolve_collect_mappings,
1935 // but from_interval is more complicated because of phi functions
1936 BlockBegin* to_block = handler->entry_block();
1937 Interval* to_interval = interval_at_block_begin(to_block, reg_num);
1938
1939 if (phi != nullptr) {
1940 // phi function of the exception entry block
1941 // no moves are created for this phi function in the LIR_Generator, so the
1942 // interval at the throwing instruction must be searched using the operands
1943 // of the phi function
1944 Value from_value = phi->operand_at(handler->phi_operand());
1945 if (from_value == nullptr) {
1946 // We have reached here in a kotlin application running with JVMTI
1947 // capability "can_access_local_variables".
1948 // The illegal state is not yet propagated to this phi. Do it here.
1949 phi->make_illegal();
1950 // We can skip the illegal phi edge.
1951 return;
1952 }
1953
1954 // with phi functions it can happen that the same from_value is used in
1955 // multiple mappings, so notify move-resolver that this is allowed
1956 move_resolver.set_multiple_reads_allowed();
1957
1958 Constant* con = from_value->as_Constant();
1959 if (con != nullptr && (!con->is_pinned() || con->operand()->is_constant())) {
1960 // Need a mapping from constant to interval if unpinned (may have no register) or if the operand is a constant (no register).
1961 move_resolver.add_mapping(LIR_OprFact::value_type(con->type()), to_interval);
1962 } else {
1963 // search split child at the throwing op_id
1964 Interval* from_interval = interval_at_op_id(from_value->operand()->vreg_number(), throwing_op_id);
1965 move_resolver.add_mapping(from_interval, to_interval);
1966 }
1967 } else {
1968 // no phi function, so use reg_num also for from_interval
1969 // search split child at the throwing op_id
1970 Interval* from_interval = interval_at_op_id(reg_num, throwing_op_id);
1971 if (from_interval != to_interval) {
1972 // optimization to reduce number of moves: when to_interval is on stack and
1973 // the stack slot is known to be always correct, then no move is necessary
1974 if (!from_interval->always_in_memory() || from_interval->canonical_spill_slot() != to_interval->assigned_reg()) {
1975 move_resolver.add_mapping(from_interval, to_interval);
1976 }
1977 }
1978 }
1979 }
1980
1981 void LinearScan::resolve_exception_edge(XHandler* handler, int throwing_op_id, MoveResolver &move_resolver) {
1982 TRACE_LINEAR_SCAN(4, tty->print_cr("resolving exception handler B%d: throwing_op_id=%d", handler->entry_block()->block_id(), throwing_op_id));
1983
1984 DEBUG_ONLY(move_resolver.check_empty());
1985 assert(handler->lir_op_id() == -1, "already processed this xhandler");
1986 DEBUG_ONLY(handler->set_lir_op_id(throwing_op_id));
1987 assert(handler->entry_code() == nullptr, "code already present");
1988
1989 // visit all registers where the live_in bit is set
1990 BlockBegin* block = handler->entry_block();
1991 auto resolver = [&](BitMap::idx_t index) {
1992 int r = static_cast<int>(index);
1993 resolve_exception_edge(handler, throwing_op_id, r, nullptr, move_resolver);
1994 };
1995 block->live_in().iterate(resolver, 0, live_set_size());
1996
1997 // the live_in bits are not set for phi functions of the xhandler entry, so iterate them separately
1998 for_each_phi_fun(block, phi,
1999 if (!phi->is_illegal()) { resolve_exception_edge(handler, throwing_op_id, phi->operand()->vreg_number(), phi, move_resolver); }
2000 );
2001
2002 if (move_resolver.has_mappings()) {
2003 LIR_List* entry_code = new LIR_List(compilation());
2004 move_resolver.set_insert_position(entry_code, 0);
2005 move_resolver.resolve_and_append_moves();
2006
2007 entry_code->jump(handler->entry_block());
2008 handler->set_entry_code(entry_code);
2009 }
2010 }
2011
2012
2013 void LinearScan::resolve_exception_handlers() {
2014 MoveResolver move_resolver(this);
2015 LIR_OpVisitState visitor;
2016 int num_blocks = block_count();
2017
2018 int i;
2019 for (i = 0; i < num_blocks; i++) {
2020 BlockBegin* block = block_at(i);
2021 if (block->is_set(BlockBegin::exception_entry_flag)) {
2022 resolve_exception_entry(block, move_resolver);
2023 }
2024 }
2025
2026 for (i = 0; i < num_blocks; i++) {
2027 BlockBegin* block = block_at(i);
2028 LIR_List* ops = block->lir();
2029 int num_ops = ops->length();
2030
2031 // iterate all instructions of the block. skip the first because it is always a label
2032 assert(visitor.no_operands(ops->at(0)), "first operation must always be a label");
2033 for (int j = 1; j < num_ops; j++) {
2034 LIR_Op* op = ops->at(j);
2035 int op_id = op->id();
2036
2037 if (op_id != -1 && has_info(op_id)) {
2038 // visit operation to collect all operands
2039 visitor.visit(op);
2040 assert(visitor.info_count() > 0, "should not visit otherwise");
2041
2042 XHandlers* xhandlers = visitor.all_xhandler();
2043 int n = xhandlers->length();
2044 for (int k = 0; k < n; k++) {
2045 resolve_exception_edge(xhandlers->handler_at(k), op_id, move_resolver);
2046 }
2047
2048 #ifdef ASSERT
2049 } else {
2050 visitor.visit(op);
2051 assert(visitor.all_xhandler()->length() == 0, "missed exception handler");
2052 #endif
2053 }
2054 }
2055 }
2056 }
2057
2058
2059 // ********** Phase 7: assign register numbers back to LIR
2060 // (includes computation of debug information and oop maps)
2061
2062 VMReg LinearScan::vm_reg_for_interval(Interval* interval) {
2063 VMReg reg = interval->cached_vm_reg();
2064 if (!reg->is_valid() ) {
2065 reg = vm_reg_for_operand(operand_for_interval(interval));
2066 interval->set_cached_vm_reg(reg);
2067 }
2068 assert(reg == vm_reg_for_operand(operand_for_interval(interval)), "wrong cached value");
2069 return reg;
2070 }
2071
2072 VMReg LinearScan::vm_reg_for_operand(LIR_Opr opr) {
2073 assert(opr->is_oop(), "currently only implemented for oop operands");
2074 return frame_map()->regname(opr);
2075 }
2076
2077
2078 LIR_Opr LinearScan::operand_for_interval(Interval* interval) {
2079 LIR_Opr opr = interval->cached_opr();
2080 if (opr->is_illegal()) {
2081 opr = calc_operand_for_interval(interval);
2082 interval->set_cached_opr(opr);
2083 }
2084
2085 assert(opr == calc_operand_for_interval(interval), "wrong cached value");
2086 return opr;
2087 }
2088
2089 LIR_Opr LinearScan::calc_operand_for_interval(const Interval* interval) {
2090 int assigned_reg = interval->assigned_reg();
2091 BasicType type = interval->type();
2092
2093 if (assigned_reg >= nof_regs) {
2094 // stack slot
2095 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2096 return LIR_OprFact::stack(assigned_reg - nof_regs, type);
2097
2098 } else {
2099 // register
2100 switch (type) {
2101 case T_OBJECT: {
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_oop(assigned_reg);
2105 }
2106
2107 case T_ADDRESS: {
2108 assert(assigned_reg >= pd_first_cpu_reg && assigned_reg <= pd_last_cpu_reg, "no cpu register");
2109 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2110 return LIR_OprFact::single_cpu_address(assigned_reg);
2111 }
2112
2113 case T_METADATA: {
2114 assert(assigned_reg >= pd_first_cpu_reg && assigned_reg <= pd_last_cpu_reg, "no cpu register");
2115 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2116 return LIR_OprFact::single_cpu_metadata(assigned_reg);
2117 }
2118
2119 #ifdef __SOFTFP__
2120 case T_FLOAT: // fall through
2121 #endif // __SOFTFP__
2122 case T_INT: {
2123 assert(assigned_reg >= pd_first_cpu_reg && assigned_reg <= pd_last_cpu_reg, "no cpu register");
2124 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2125 return LIR_OprFact::single_cpu(assigned_reg);
2126 }
2127
2128 #ifdef __SOFTFP__
2129 case T_DOUBLE: // fall through
2130 #endif // __SOFTFP__
2131 case T_LONG: {
2132 int assigned_regHi = interval->assigned_regHi();
2133 assert(assigned_reg >= pd_first_cpu_reg && assigned_reg <= pd_last_cpu_reg, "no cpu register");
2134 assert(num_physical_regs(T_LONG) == 1 ||
2135 (assigned_regHi >= pd_first_cpu_reg && assigned_regHi <= pd_last_cpu_reg), "no cpu register");
2136
2137 assert(assigned_reg != assigned_regHi, "invalid allocation");
2138 assert(num_physical_regs(T_LONG) == 1 || assigned_reg < assigned_regHi,
2139 "register numbers must be sorted (ensure that e.g. a move from eax,ebx to ebx,eax can not occur)");
2140 assert((assigned_regHi != any_reg) ^ (num_physical_regs(T_LONG) == 1), "must be match");
2141 if (requires_adjacent_regs(T_LONG)) {
2142 assert(assigned_reg % 2 == 0 && assigned_reg + 1 == assigned_regHi, "must be sequential and even");
2143 }
2144
2145 #ifdef _LP64
2146 return LIR_OprFact::double_cpu(assigned_reg, assigned_reg);
2147 #else
2148 return LIR_OprFact::double_cpu(assigned_reg, assigned_regHi);
2149 #endif // LP64
2150 }
2151
2152 #ifndef __SOFTFP__
2153 case T_FLOAT: {
2154 #ifdef X86
2155 if (UseSSE >= 1) {
2156 int last_xmm_reg = pd_last_xmm_reg;
2157 #ifdef _LP64
2158 if (UseAVX < 3) {
2159 last_xmm_reg = pd_first_xmm_reg + (pd_nof_xmm_regs_frame_map / 2) - 1;
2160 }
2161 #endif // LP64
2162 assert(assigned_reg >= pd_first_xmm_reg && assigned_reg <= last_xmm_reg, "no xmm register");
2163 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2164 return LIR_OprFact::single_xmm(assigned_reg - pd_first_xmm_reg);
2165 }
2166 #endif // X86
2167
2168 assert(assigned_reg >= pd_first_fpu_reg && assigned_reg <= pd_last_fpu_reg, "no fpu register");
2169 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2170 return LIR_OprFact::single_fpu(assigned_reg - pd_first_fpu_reg);
2171 }
2172
2173 case T_DOUBLE: {
2174 #ifdef X86
2175 if (UseSSE >= 2) {
2176 int last_xmm_reg = pd_last_xmm_reg;
2177 #ifdef _LP64
2178 if (UseAVX < 3) {
2179 last_xmm_reg = pd_first_xmm_reg + (pd_nof_xmm_regs_frame_map / 2) - 1;
2180 }
2181 #endif // LP64
2182 assert(assigned_reg >= pd_first_xmm_reg && assigned_reg <= last_xmm_reg, "no xmm register");
2183 assert(interval->assigned_regHi() == any_reg, "must not have hi register (double xmm values are stored in one register)");
2184 return LIR_OprFact::double_xmm(assigned_reg - pd_first_xmm_reg);
2185 }
2186 #endif // X86
2187
2188 #if defined(ARM32)
2189 assert(assigned_reg >= pd_first_fpu_reg && assigned_reg <= pd_last_fpu_reg, "no fpu register");
2190 assert(interval->assigned_regHi() >= pd_first_fpu_reg && interval->assigned_regHi() <= pd_last_fpu_reg, "no fpu register");
2191 assert(assigned_reg % 2 == 0 && assigned_reg + 1 == interval->assigned_regHi(), "must be sequential and even");
2192 LIR_Opr result = LIR_OprFact::double_fpu(assigned_reg - pd_first_fpu_reg, interval->assigned_regHi() - pd_first_fpu_reg);
2193 #else
2194 assert(assigned_reg >= pd_first_fpu_reg && assigned_reg <= pd_last_fpu_reg, "no fpu register");
2195 assert(interval->assigned_regHi() == any_reg, "must not have hi register (double fpu values are stored in one register on Intel)");
2196 LIR_Opr result = LIR_OprFact::double_fpu(assigned_reg - pd_first_fpu_reg);
2197 #endif
2198 return result;
2199 }
2200 #endif // __SOFTFP__
2201
2202 default: {
2203 ShouldNotReachHere();
2204 return LIR_OprFact::illegalOpr;
2205 }
2206 }
2207 }
2208 }
2209
2210 LIR_Opr LinearScan::canonical_spill_opr(Interval* interval) {
2211 assert(interval->canonical_spill_slot() >= nof_regs, "canonical spill slot not set");
2212 return LIR_OprFact::stack(interval->canonical_spill_slot() - nof_regs, interval->type());
2213 }
2214
2215 LIR_Opr LinearScan::color_lir_opr(LIR_Opr opr, int op_id, LIR_OpVisitState::OprMode mode) {
2216 assert(opr->is_virtual(), "should not call this otherwise");
2217
2218 Interval* interval = interval_at(opr->vreg_number());
2219 assert(interval != nullptr, "interval must exist");
2220
2221 if (op_id != -1) {
2222 #ifdef ASSERT
2223 BlockBegin* block = block_of_op_with_id(op_id);
2224 if (block->number_of_sux() <= 1 && op_id == block->last_lir_instruction_id()) {
2225 // check if spill moves could have been appended at the end of this block, but
2226 // before the branch instruction. So the split child information for this branch would
2227 // be incorrect.
2228 LIR_OpBranch* branch = block->lir()->instructions_list()->last()->as_OpBranch();
2229 if (branch != nullptr) {
2230 if (block->live_out().at(opr->vreg_number())) {
2231 assert(branch->cond() == lir_cond_always, "block does not end with an unconditional jump");
2232 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)");
2233 }
2234 }
2235 }
2236 #endif
2237
2238 // operands are not changed when an interval is split during allocation,
2239 // so search the right interval here
2240 interval = split_child_at_op_id(interval, op_id, mode);
2241 }
2242
2243 LIR_Opr res = operand_for_interval(interval);
2244
2245 #ifdef X86
2246 // new semantic for is_last_use: not only set on definite end of interval,
2247 // but also before hole
2248 // This may still miss some cases (e.g. for dead values), but it is not necessary that the
2249 // last use information is completely correct
2250 // information is only needed for fpu stack allocation
2251 if (res->is_fpu_register()) {
2252 if (opr->is_last_use() || op_id == interval->to() || (op_id != -1 && interval->has_hole_between(op_id, op_id + 1))) {
2253 assert(op_id == -1 || !is_block_begin(op_id), "holes at begin of block may also result from control flow");
2254 res = res->make_last_use();
2255 }
2256 }
2257 #endif
2258
2259 assert(!gen()->is_vreg_flag_set(opr->vreg_number(), LIRGenerator::callee_saved) || !FrameMap::is_caller_save_register(res), "bad allocation");
2260
2261 return res;
2262 }
2263
2264
2265 #ifdef ASSERT
2266 // some methods used to check correctness of debug information
2267
2268 void assert_no_register_values(GrowableArray<ScopeValue*>* values) {
2269 if (values == nullptr) {
2270 return;
2271 }
2272
2273 for (int i = 0; i < values->length(); i++) {
2274 ScopeValue* value = values->at(i);
2275
2276 if (value->is_location()) {
2277 Location location = ((LocationValue*)value)->location();
2278 assert(location.where() == Location::on_stack, "value is in register");
2279 }
2280 }
2281 }
2282
2283 void assert_no_register_values(GrowableArray<MonitorValue*>* values) {
2284 if (values == nullptr) {
2285 return;
2286 }
2287
2288 for (int i = 0; i < values->length(); i++) {
2289 MonitorValue* value = values->at(i);
2290
2291 if (value->owner()->is_location()) {
2292 Location location = ((LocationValue*)value->owner())->location();
2293 assert(location.where() == Location::on_stack, "owner is in register");
2294 }
2295 assert(value->basic_lock().where() == Location::on_stack, "basic_lock is in register");
2296 }
2297 }
2298
2299 static void assert_equal(Location l1, Location l2) {
2300 assert(l1.where() == l2.where() && l1.type() == l2.type() && l1.offset() == l2.offset(), "");
2301 }
2302
2303 static void assert_equal(ScopeValue* v1, ScopeValue* v2) {
2304 if (v1->is_location()) {
2305 assert(v2->is_location(), "");
2306 assert_equal(((LocationValue*)v1)->location(), ((LocationValue*)v2)->location());
2307 } else if (v1->is_constant_int()) {
2308 assert(v2->is_constant_int(), "");
2309 assert(((ConstantIntValue*)v1)->value() == ((ConstantIntValue*)v2)->value(), "");
2310 } else if (v1->is_constant_double()) {
2311 assert(v2->is_constant_double(), "");
2312 assert(((ConstantDoubleValue*)v1)->value() == ((ConstantDoubleValue*)v2)->value(), "");
2313 } else if (v1->is_constant_long()) {
2314 assert(v2->is_constant_long(), "");
2315 assert(((ConstantLongValue*)v1)->value() == ((ConstantLongValue*)v2)->value(), "");
2316 } else if (v1->is_constant_oop()) {
2317 assert(v2->is_constant_oop(), "");
2318 assert(((ConstantOopWriteValue*)v1)->value() == ((ConstantOopWriteValue*)v2)->value(), "");
2319 } else {
2320 ShouldNotReachHere();
2321 }
2322 }
2323
2324 static void assert_equal(MonitorValue* m1, MonitorValue* m2) {
2325 assert_equal(m1->owner(), m2->owner());
2326 assert_equal(m1->basic_lock(), m2->basic_lock());
2327 }
2328
2329 static void assert_equal(IRScopeDebugInfo* d1, IRScopeDebugInfo* d2) {
2330 assert(d1->scope() == d2->scope(), "not equal");
2331 assert(d1->bci() == d2->bci(), "not equal");
2332
2333 if (d1->locals() != nullptr) {
2334 assert(d1->locals() != nullptr && d2->locals() != nullptr, "not equal");
2335 assert(d1->locals()->length() == d2->locals()->length(), "not equal");
2336 for (int i = 0; i < d1->locals()->length(); i++) {
2337 assert_equal(d1->locals()->at(i), d2->locals()->at(i));
2338 }
2339 } else {
2340 assert(d1->locals() == nullptr && d2->locals() == nullptr, "not equal");
2341 }
2342
2343 if (d1->expressions() != nullptr) {
2344 assert(d1->expressions() != nullptr && d2->expressions() != nullptr, "not equal");
2345 assert(d1->expressions()->length() == d2->expressions()->length(), "not equal");
2346 for (int i = 0; i < d1->expressions()->length(); i++) {
2347 assert_equal(d1->expressions()->at(i), d2->expressions()->at(i));
2348 }
2349 } else {
2350 assert(d1->expressions() == nullptr && d2->expressions() == nullptr, "not equal");
2351 }
2352
2353 if (d1->monitors() != nullptr) {
2354 assert(d1->monitors() != nullptr && d2->monitors() != nullptr, "not equal");
2355 assert(d1->monitors()->length() == d2->monitors()->length(), "not equal");
2356 for (int i = 0; i < d1->monitors()->length(); i++) {
2357 assert_equal(d1->monitors()->at(i), d2->monitors()->at(i));
2358 }
2359 } else {
2360 assert(d1->monitors() == nullptr && d2->monitors() == nullptr, "not equal");
2361 }
2362
2363 if (d1->caller() != nullptr) {
2364 assert(d1->caller() != nullptr && d2->caller() != nullptr, "not equal");
2365 assert_equal(d1->caller(), d2->caller());
2366 } else {
2367 assert(d1->caller() == nullptr && d2->caller() == nullptr, "not equal");
2368 }
2369 }
2370
2371 static void check_stack_depth(CodeEmitInfo* info, int stack_end) {
2372 if (info->stack()->bci() != SynchronizationEntryBCI && !info->scope()->method()->is_native()) {
2373 Bytecodes::Code code = info->scope()->method()->java_code_at_bci(info->stack()->bci());
2374 switch (code) {
2375 case Bytecodes::_ifnull : // fall through
2376 case Bytecodes::_ifnonnull : // fall through
2377 case Bytecodes::_ifeq : // fall through
2378 case Bytecodes::_ifne : // fall through
2379 case Bytecodes::_iflt : // fall through
2380 case Bytecodes::_ifge : // fall through
2381 case Bytecodes::_ifgt : // fall through
2382 case Bytecodes::_ifle : // fall through
2383 case Bytecodes::_if_icmpeq : // fall through
2384 case Bytecodes::_if_icmpne : // fall through
2385 case Bytecodes::_if_icmplt : // fall through
2386 case Bytecodes::_if_icmpge : // fall through
2387 case Bytecodes::_if_icmpgt : // fall through
2388 case Bytecodes::_if_icmple : // fall through
2389 case Bytecodes::_if_acmpeq : // fall through
2390 case Bytecodes::_if_acmpne :
2391 assert(stack_end >= -Bytecodes::depth(code), "must have non-empty expression stack at if bytecode");
2392 break;
2393 default:
2394 break;
2395 }
2396 }
2397 }
2398
2399 #endif // ASSERT
2400
2401
2402 IntervalWalker* LinearScan::init_compute_oop_maps() {
2403 // setup lists of potential oops for walking
2404 Interval* oop_intervals;
2405 Interval* non_oop_intervals;
2406
2407 create_unhandled_lists(&oop_intervals, &non_oop_intervals, is_oop_interval, nullptr);
2408
2409 // intervals that have no oops inside need not to be processed
2410 // to ensure a walking until the last instruction id, add a dummy interval
2411 // with a high operation id
2412 non_oop_intervals = new Interval(any_reg);
2413 non_oop_intervals->add_range(max_jint - 2, max_jint - 1);
2414
2415 return new IntervalWalker(this, oop_intervals, non_oop_intervals);
2416 }
2417
2418
2419 OopMap* LinearScan::compute_oop_map(IntervalWalker* iw, LIR_Op* op, CodeEmitInfo* info, bool is_call_site) {
2420 TRACE_LINEAR_SCAN(3, tty->print_cr("creating oop map at op_id %d", op->id()));
2421
2422 // walk before the current operation -> intervals that start at
2423 // the operation (= output operands of the operation) are not
2424 // included in the oop map
2425 iw->walk_before(op->id());
2426
2427 int frame_size = frame_map()->framesize();
2428 int arg_count = frame_map()->oop_map_arg_count();
2429 OopMap* map = new OopMap(frame_size, arg_count);
2430
2431 // Iterate through active intervals
2432 for (Interval* interval = iw->active_first(fixedKind); interval != Interval::end(); interval = interval->next()) {
2433 int assigned_reg = interval->assigned_reg();
2434
2435 assert(interval->current_from() <= op->id() && op->id() <= interval->current_to(), "interval should not be active otherwise");
2436 assert(interval->assigned_regHi() == any_reg, "oop must be single word");
2437 assert(interval->reg_num() >= LIR_Opr::vreg_base, "fixed interval found");
2438
2439 // Check if this range covers the instruction. Intervals that
2440 // start or end at the current operation are not included in the
2441 // oop map, except in the case of patching moves. For patching
2442 // moves, any intervals which end at this instruction are included
2443 // in the oop map since we may safepoint while doing the patch
2444 // before we've consumed the inputs.
2445 if (op->is_patching() || op->id() < interval->current_to()) {
2446
2447 // caller-save registers must not be included into oop-maps at calls
2448 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");
2449
2450 VMReg name = vm_reg_for_interval(interval);
2451 set_oop(map, name);
2452
2453 // Spill optimization: when the stack value is guaranteed to be always correct,
2454 // then it must be added to the oop map even if the interval is currently in a register
2455 if (interval->always_in_memory() &&
2456 op->id() > interval->spill_definition_pos() &&
2457 interval->assigned_reg() != interval->canonical_spill_slot()) {
2458 assert(interval->spill_definition_pos() > 0, "position not set correctly");
2459 assert(interval->canonical_spill_slot() >= LinearScan::nof_regs, "no spill slot assigned");
2460 assert(interval->assigned_reg() < LinearScan::nof_regs, "interval is on stack, so stack slot is registered twice");
2461
2462 set_oop(map, frame_map()->slot_regname(interval->canonical_spill_slot() - LinearScan::nof_regs));
2463 }
2464 }
2465 }
2466
2467 // add oops from lock stack
2468 assert(info->stack() != nullptr, "CodeEmitInfo must always have a stack");
2469 int locks_count = info->stack()->total_locks_size();
2470 for (int i = 0; i < locks_count; i++) {
2471 set_oop(map, frame_map()->monitor_object_regname(i));
2472 }
2473
2474 return map;
2475 }
2476
2477
2478 void LinearScan::compute_oop_map(IntervalWalker* iw, const LIR_OpVisitState &visitor, LIR_Op* op) {
2479 assert(visitor.info_count() > 0, "no oop map needed");
2480
2481 // compute oop_map only for first CodeEmitInfo
2482 // because it is (in most cases) equal for all other infos of the same operation
2483 CodeEmitInfo* first_info = visitor.info_at(0);
2484 OopMap* first_oop_map = compute_oop_map(iw, op, first_info, visitor.has_call());
2485
2486 for (int i = 0; i < visitor.info_count(); i++) {
2487 CodeEmitInfo* info = visitor.info_at(i);
2488 OopMap* oop_map = first_oop_map;
2489
2490 // compute worst case interpreter size in case of a deoptimization
2491 _compilation->update_interpreter_frame_size(info->interpreter_frame_size());
2492
2493 if (info->stack()->locks_size() != first_info->stack()->locks_size()) {
2494 // this info has a different number of locks then the precomputed oop map
2495 // (possible for lock and unlock instructions) -> compute oop map with
2496 // correct lock information
2497 oop_map = compute_oop_map(iw, op, info, visitor.has_call());
2498 }
2499
2500 if (info->_oop_map == nullptr) {
2501 info->_oop_map = oop_map;
2502 } else {
2503 // a CodeEmitInfo can not be shared between different LIR-instructions
2504 // because interval splitting can occur anywhere between two instructions
2505 // and so the oop maps must be different
2506 // -> check if the already set oop_map is exactly the one calculated for this operation
2507 assert(info->_oop_map == oop_map, "same CodeEmitInfo used for multiple LIR instructions");
2508 }
2509 }
2510 }
2511
2512
2513 // frequently used constants
2514 // Allocate them with new so they are never destroyed (otherwise, a
2515 // forced exit could destroy these objects while they are still in
2516 // use).
2517 ConstantOopWriteValue* LinearScan::_oop_null_scope_value = new (mtCompiler) ConstantOopWriteValue(nullptr);
2518 ConstantIntValue* LinearScan::_int_m1_scope_value = new (mtCompiler) ConstantIntValue(-1);
2519 ConstantIntValue* LinearScan::_int_0_scope_value = new (mtCompiler) ConstantIntValue((jint)0);
2520 ConstantIntValue* LinearScan::_int_1_scope_value = new (mtCompiler) ConstantIntValue(1);
2521 ConstantIntValue* LinearScan::_int_2_scope_value = new (mtCompiler) ConstantIntValue(2);
2522 LocationValue* _illegal_value = new (mtCompiler) LocationValue(Location());
2523
2524 void LinearScan::init_compute_debug_info() {
2525 // cache for frequently used scope values
2526 // (cpu registers and stack slots)
2527 int cache_size = (LinearScan::nof_cpu_regs + frame_map()->argcount() + max_spills()) * 2;
2528 _scope_value_cache = ScopeValueArray(cache_size, cache_size, nullptr);
2529 }
2530
2531 MonitorValue* LinearScan::location_for_monitor_index(int monitor_index) {
2532 Location loc;
2533 if (!frame_map()->location_for_monitor_object(monitor_index, &loc)) {
2534 bailout("too large frame");
2535 }
2536 ScopeValue* object_scope_value = new LocationValue(loc);
2537
2538 if (!frame_map()->location_for_monitor_lock(monitor_index, &loc)) {
2539 bailout("too large frame");
2540 }
2541 return new MonitorValue(object_scope_value, loc);
2542 }
2543
2544 LocationValue* LinearScan::location_for_name(int name, Location::Type loc_type) {
2545 Location loc;
2546 if (!frame_map()->locations_for_slot(name, loc_type, &loc)) {
2547 bailout("too large frame");
2548 }
2549 return new LocationValue(loc);
2550 }
2551
2552
2553 int LinearScan::append_scope_value_for_constant(LIR_Opr opr, GrowableArray<ScopeValue*>* scope_values) {
2554 assert(opr->is_constant(), "should not be called otherwise");
2555
2556 LIR_Const* c = opr->as_constant_ptr();
2557 BasicType t = c->type();
2558 switch (t) {
2559 case T_OBJECT: {
2560 jobject value = c->as_jobject();
2561 if (value == nullptr) {
2562 scope_values->append(_oop_null_scope_value);
2563 } else {
2564 scope_values->append(new ConstantOopWriteValue(c->as_jobject()));
2565 }
2566 return 1;
2567 }
2568
2569 case T_INT: // fall through
2570 case T_FLOAT: {
2571 int value = c->as_jint_bits();
2572 switch (value) {
2573 case -1: scope_values->append(_int_m1_scope_value); break;
2574 case 0: scope_values->append(_int_0_scope_value); break;
2575 case 1: scope_values->append(_int_1_scope_value); break;
2576 case 2: scope_values->append(_int_2_scope_value); break;
2577 default: scope_values->append(new ConstantIntValue(c->as_jint_bits())); break;
2578 }
2579 return 1;
2580 }
2581
2582 case T_LONG: // fall through
2583 case T_DOUBLE: {
2584 #ifdef _LP64
2585 scope_values->append(_int_0_scope_value);
2586 scope_values->append(new ConstantLongValue(c->as_jlong_bits()));
2587 #else
2588 if (hi_word_offset_in_bytes > lo_word_offset_in_bytes) {
2589 scope_values->append(new ConstantIntValue(c->as_jint_hi_bits()));
2590 scope_values->append(new ConstantIntValue(c->as_jint_lo_bits()));
2591 } else {
2592 scope_values->append(new ConstantIntValue(c->as_jint_lo_bits()));
2593 scope_values->append(new ConstantIntValue(c->as_jint_hi_bits()));
2594 }
2595 #endif
2596 return 2;
2597 }
2598
2599 case T_ADDRESS: {
2600 #ifdef _LP64
2601 scope_values->append(new ConstantLongValue(c->as_jint()));
2602 #else
2603 scope_values->append(new ConstantIntValue(c->as_jint()));
2604 #endif
2605 return 1;
2606 }
2607
2608 default:
2609 ShouldNotReachHere();
2610 return -1;
2611 }
2612 }
2613
2614 int LinearScan::append_scope_value_for_operand(LIR_Opr opr, GrowableArray<ScopeValue*>* scope_values) {
2615 if (opr->is_single_stack()) {
2616 int stack_idx = opr->single_stack_ix();
2617 bool is_oop = opr->is_oop_register();
2618 int cache_idx = (stack_idx + LinearScan::nof_cpu_regs) * 2 + (is_oop ? 1 : 0);
2619
2620 ScopeValue* sv = _scope_value_cache.at(cache_idx);
2621 if (sv == nullptr) {
2622 Location::Type loc_type = is_oop ? Location::oop : Location::normal;
2623 sv = location_for_name(stack_idx, loc_type);
2624 _scope_value_cache.at_put(cache_idx, sv);
2625 }
2626
2627 // check if cached value is correct
2628 DEBUG_ONLY(assert_equal(sv, location_for_name(stack_idx, is_oop ? Location::oop : Location::normal)));
2629
2630 scope_values->append(sv);
2631 return 1;
2632
2633 } else if (opr->is_single_cpu()) {
2634 bool is_oop = opr->is_oop_register();
2635 int cache_idx = opr->cpu_regnr() * 2 + (is_oop ? 1 : 0);
2636 Location::Type int_loc_type = NOT_LP64(Location::normal) LP64_ONLY(Location::int_in_long);
2637
2638 ScopeValue* sv = _scope_value_cache.at(cache_idx);
2639 if (sv == nullptr) {
2640 Location::Type loc_type = is_oop ? Location::oop : int_loc_type;
2641 VMReg rname = frame_map()->regname(opr);
2642 sv = new LocationValue(Location::new_reg_loc(loc_type, rname));
2643 _scope_value_cache.at_put(cache_idx, sv);
2644 }
2645
2646 // check if cached value is correct
2647 DEBUG_ONLY(assert_equal(sv, new LocationValue(Location::new_reg_loc(is_oop ? Location::oop : int_loc_type, frame_map()->regname(opr)))));
2648
2649 scope_values->append(sv);
2650 return 1;
2651
2652 #ifdef X86
2653 } else if (opr->is_single_xmm()) {
2654 VMReg rname = opr->as_xmm_float_reg()->as_VMReg();
2655 LocationValue* sv = new LocationValue(Location::new_reg_loc(Location::normal, rname));
2656
2657 scope_values->append(sv);
2658 return 1;
2659 #endif
2660
2661 } else if (opr->is_single_fpu()) {
2662 #if defined(AMD64)
2663 assert(false, "FPU not used on x86-64");
2664 #endif
2665 Location::Type loc_type = float_saved_as_double ? Location::float_in_dbl : Location::normal;
2666 VMReg rname = frame_map()->fpu_regname(opr->fpu_regnr());
2667 #ifndef __SOFTFP__
2668 #ifndef VM_LITTLE_ENDIAN
2669 // On S390 a (single precision) float value occupies only the high
2670 // word of the full double register. So when the double register is
2671 // stored to memory (e.g. by the RegisterSaver), then the float value
2672 // is found at offset 0. I.e. the code below is not needed on S390.
2673 #ifndef S390
2674 if (! float_saved_as_double) {
2675 // On big endian system, we may have an issue if float registers use only
2676 // the low half of the (same) double registers.
2677 // Both the float and the double could have the same regnr but would correspond
2678 // to two different addresses once saved.
2679
2680 // get next safely (no assertion checks)
2681 VMReg next = VMRegImpl::as_VMReg(1+rname->value());
2682 if (next->is_reg() &&
2683 (next->as_FloatRegister() == rname->as_FloatRegister())) {
2684 // the back-end does use the same numbering for the double and the float
2685 rname = next; // VMReg for the low bits, e.g. the real VMReg for the float
2686 }
2687 }
2688 #endif // !S390
2689 #endif
2690 #endif
2691 LocationValue* sv = new LocationValue(Location::new_reg_loc(loc_type, rname));
2692
2693 scope_values->append(sv);
2694 return 1;
2695
2696 } else {
2697 // double-size operands
2698
2699 ScopeValue* first;
2700 ScopeValue* second;
2701
2702 if (opr->is_double_stack()) {
2703 #ifdef _LP64
2704 Location loc1;
2705 Location::Type loc_type = opr->type() == T_LONG ? Location::lng : Location::dbl;
2706 if (!frame_map()->locations_for_slot(opr->double_stack_ix(), loc_type, &loc1, nullptr)) {
2707 bailout("too large frame");
2708 }
2709
2710 first = new LocationValue(loc1);
2711 second = _int_0_scope_value;
2712 #else
2713 Location loc1, loc2;
2714 if (!frame_map()->locations_for_slot(opr->double_stack_ix(), Location::normal, &loc1, &loc2)) {
2715 bailout("too large frame");
2716 }
2717 first = new LocationValue(loc1);
2718 second = new LocationValue(loc2);
2719 #endif // _LP64
2720
2721 } else if (opr->is_double_cpu()) {
2722 #ifdef _LP64
2723 VMReg rname_first = opr->as_register_lo()->as_VMReg();
2724 first = new LocationValue(Location::new_reg_loc(Location::lng, rname_first));
2725 second = _int_0_scope_value;
2726 #else
2727 VMReg rname_first = opr->as_register_lo()->as_VMReg();
2728 VMReg rname_second = opr->as_register_hi()->as_VMReg();
2729
2730 if (hi_word_offset_in_bytes < lo_word_offset_in_bytes) {
2731 // lo/hi and swapped relative to first and second, so swap them
2732 VMReg tmp = rname_first;
2733 rname_first = rname_second;
2734 rname_second = tmp;
2735 }
2736
2737 first = new LocationValue(Location::new_reg_loc(Location::normal, rname_first));
2738 second = new LocationValue(Location::new_reg_loc(Location::normal, rname_second));
2739 #endif //_LP64
2740
2741
2742 #ifdef X86
2743 } else if (opr->is_double_xmm()) {
2744 assert(opr->fpu_regnrLo() == opr->fpu_regnrHi(), "assumed in calculation");
2745 VMReg rname_first = opr->as_xmm_double_reg()->as_VMReg();
2746 # ifdef _LP64
2747 first = new LocationValue(Location::new_reg_loc(Location::dbl, rname_first));
2748 second = _int_0_scope_value;
2749 # else
2750 first = new LocationValue(Location::new_reg_loc(Location::normal, rname_first));
2751 // %%% This is probably a waste but we'll keep things as they were for now
2752 if (true) {
2753 VMReg rname_second = rname_first->next();
2754 second = new LocationValue(Location::new_reg_loc(Location::normal, rname_second));
2755 }
2756 # endif
2757 #endif
2758
2759 } else if (opr->is_double_fpu()) {
2760 // On SPARC, fpu_regnrLo/fpu_regnrHi represents the two halves of
2761 // the double as float registers in the native ordering. On X86,
2762 // fpu_regnrLo is a FPU stack slot whose VMReg represents
2763 // the low-order word of the double and fpu_regnrLo + 1 is the
2764 // name for the other half. *first and *second must represent the
2765 // least and most significant words, respectively.
2766
2767 #ifdef AMD64
2768 assert(false, "FPU not used on x86-64");
2769 #endif
2770 #ifdef ARM32
2771 assert(opr->fpu_regnrHi() == opr->fpu_regnrLo() + 1, "assumed in calculation (only fpu_regnrLo is used)");
2772 #endif
2773
2774 #ifdef VM_LITTLE_ENDIAN
2775 VMReg rname_first = frame_map()->fpu_regname(opr->fpu_regnrLo());
2776 #else
2777 VMReg rname_first = frame_map()->fpu_regname(opr->fpu_regnrHi());
2778 #endif
2779
2780 #ifdef _LP64
2781 first = new LocationValue(Location::new_reg_loc(Location::dbl, rname_first));
2782 second = _int_0_scope_value;
2783 #else
2784 first = new LocationValue(Location::new_reg_loc(Location::normal, rname_first));
2785 // %%% This is probably a waste but we'll keep things as they were for now
2786 if (true) {
2787 VMReg rname_second = rname_first->next();
2788 second = new LocationValue(Location::new_reg_loc(Location::normal, rname_second));
2789 }
2790 #endif
2791
2792 } else {
2793 ShouldNotReachHere();
2794 first = nullptr;
2795 second = nullptr;
2796 }
2797
2798 assert(first != nullptr && second != nullptr, "must be set");
2799 // The convention the interpreter uses is that the second local
2800 // holds the first raw word of the native double representation.
2801 // This is actually reasonable, since locals and stack arrays
2802 // grow downwards in all implementations.
2803 // (If, on some machine, the interpreter's Java locals or stack
2804 // were to grow upwards, the embedded doubles would be word-swapped.)
2805 scope_values->append(second);
2806 scope_values->append(first);
2807 return 2;
2808 }
2809 }
2810
2811
2812 int LinearScan::append_scope_value(int op_id, Value value, GrowableArray<ScopeValue*>* scope_values) {
2813 if (value != nullptr) {
2814 LIR_Opr opr = value->operand();
2815 Constant* con = value->as_Constant();
2816
2817 assert(con == nullptr || opr->is_virtual() || opr->is_constant() || opr->is_illegal(), "assumption: Constant instructions have only constant operands (or illegal if constant is optimized away)");
2818 assert(con != nullptr || opr->is_virtual(), "assumption: non-Constant instructions have only virtual operands");
2819
2820 if (con != nullptr && !con->is_pinned() && !opr->is_constant()) {
2821 // Unpinned constants may have a virtual operand for a part of the lifetime
2822 // or may be illegal when it was optimized away,
2823 // so always use a constant operand
2824 opr = LIR_OprFact::value_type(con->type());
2825 }
2826 assert(opr->is_virtual() || opr->is_constant(), "other cases not allowed here");
2827
2828 if (opr->is_virtual()) {
2829 LIR_OpVisitState::OprMode mode = LIR_OpVisitState::inputMode;
2830
2831 BlockBegin* block = block_of_op_with_id(op_id);
2832 if (block->number_of_sux() == 1 && op_id == block->last_lir_instruction_id()) {
2833 // generating debug information for the last instruction of a block.
2834 // if this instruction is a branch, spill moves are inserted before this branch
2835 // and so the wrong operand would be returned (spill moves at block boundaries are not
2836 // considered in the live ranges of intervals)
2837 // Solution: use the first op_id of the branch target block instead.
2838 if (block->lir()->instructions_list()->last()->as_OpBranch() != nullptr) {
2839 if (block->live_out().at(opr->vreg_number())) {
2840 op_id = block->sux_at(0)->first_lir_instruction_id();
2841 mode = LIR_OpVisitState::outputMode;
2842 }
2843 }
2844 }
2845
2846 // Get current location of operand
2847 // The operand must be live because debug information is considered when building the intervals
2848 // if the interval is not live, color_lir_opr will cause an assertion failure
2849 opr = color_lir_opr(opr, op_id, mode);
2850 assert(!has_call(op_id) || opr->is_stack() || !is_caller_save(reg_num(opr)), "can not have caller-save register operands at calls");
2851
2852 // Append to ScopeValue array
2853 return append_scope_value_for_operand(opr, scope_values);
2854
2855 } else {
2856 assert(value->as_Constant() != nullptr, "all other instructions have only virtual operands");
2857 assert(opr->is_constant(), "operand must be constant");
2858
2859 return append_scope_value_for_constant(opr, scope_values);
2860 }
2861 } else {
2862 // append a dummy value because real value not needed
2863 scope_values->append(_illegal_value);
2864 return 1;
2865 }
2866 }
2867
2868
2869 IRScopeDebugInfo* LinearScan::compute_debug_info_for_scope(int op_id, IRScope* cur_scope, ValueStack* cur_state, ValueStack* innermost_state) {
2870 IRScopeDebugInfo* caller_debug_info = nullptr;
2871
2872 ValueStack* caller_state = cur_state->caller_state();
2873 if (caller_state != nullptr) {
2874 // process recursively to compute outermost scope first
2875 caller_debug_info = compute_debug_info_for_scope(op_id, cur_scope->caller(), caller_state, innermost_state);
2876 }
2877
2878 // initialize these to null.
2879 // If we don't need deopt info or there are no locals, expressions or monitors,
2880 // then these get recorded as no information and avoids the allocation of 0 length arrays.
2881 GrowableArray<ScopeValue*>* locals = nullptr;
2882 GrowableArray<ScopeValue*>* expressions = nullptr;
2883 GrowableArray<MonitorValue*>* monitors = nullptr;
2884
2885 // describe local variable values
2886 int nof_locals = cur_state->locals_size();
2887 if (nof_locals > 0) {
2888 locals = new GrowableArray<ScopeValue*>(nof_locals);
2889
2890 int pos = 0;
2891 while (pos < nof_locals) {
2892 assert(pos < cur_state->locals_size(), "why not?");
2893
2894 Value local = cur_state->local_at(pos);
2895 pos += append_scope_value(op_id, local, locals);
2896
2897 assert(locals->length() == pos, "must match");
2898 }
2899 assert(locals->length() == nof_locals, "wrong number of locals");
2900 }
2901 assert(nof_locals == cur_scope->method()->max_locals(), "wrong number of locals");
2902 assert(nof_locals == cur_state->locals_size(), "wrong number of locals");
2903
2904 // describe expression stack
2905 int nof_stack = cur_state->stack_size();
2906 if (nof_stack > 0) {
2907 expressions = new GrowableArray<ScopeValue*>(nof_stack);
2908
2909 int pos = 0;
2910 while (pos < nof_stack) {
2911 Value expression = cur_state->stack_at(pos);
2912 pos += append_scope_value(op_id, expression, expressions);
2913
2914 assert(expressions->length() == pos, "must match");
2915 }
2916 assert(expressions->length() == cur_state->stack_size(), "wrong number of stack entries");
2917 }
2918
2919 // describe monitors
2920 int nof_locks = cur_state->locks_size();
2921 if (nof_locks > 0) {
2922 int lock_offset = cur_state->caller_state() != nullptr ? cur_state->caller_state()->total_locks_size() : 0;
2923 monitors = new GrowableArray<MonitorValue*>(nof_locks);
2924 for (int i = 0; i < nof_locks; i++) {
2925 monitors->append(location_for_monitor_index(lock_offset + i));
2926 }
2927 }
2928
2929 return new IRScopeDebugInfo(cur_scope, cur_state->bci(), locals, expressions, monitors, caller_debug_info);
2930 }
2931
2932
2933 void LinearScan::compute_debug_info(CodeEmitInfo* info, int op_id) {
2934 TRACE_LINEAR_SCAN(3, tty->print_cr("creating debug information at op_id %d", op_id));
2935
2936 IRScope* innermost_scope = info->scope();
2937 ValueStack* innermost_state = info->stack();
2938
2939 assert(innermost_scope != nullptr && innermost_state != nullptr, "why is it missing?");
2940
2941 DEBUG_ONLY(check_stack_depth(info, innermost_state->stack_size()));
2942
2943 if (info->_scope_debug_info == nullptr) {
2944 // compute debug information
2945 info->_scope_debug_info = compute_debug_info_for_scope(op_id, innermost_scope, innermost_state, innermost_state);
2946 } else {
2947 // debug information already set. Check that it is correct from the current point of view
2948 DEBUG_ONLY(assert_equal(info->_scope_debug_info, compute_debug_info_for_scope(op_id, innermost_scope, innermost_state, innermost_state)));
2949 }
2950 }
2951
2952
2953 void LinearScan::assign_reg_num(LIR_OpList* instructions, IntervalWalker* iw) {
2954 LIR_OpVisitState visitor;
2955 int num_inst = instructions->length();
2956 bool has_dead = false;
2957
2958 for (int j = 0; j < num_inst; j++) {
2959 LIR_Op* op = instructions->at(j);
2960 if (op == nullptr) { // this can happen when spill-moves are removed in eliminate_spill_moves
2961 has_dead = true;
2962 continue;
2963 }
2964 int op_id = op->id();
2965
2966 // visit instruction to get list of operands
2967 visitor.visit(op);
2968
2969 // iterate all modes of the visitor and process all virtual operands
2970 for_each_visitor_mode(mode) {
2971 int n = visitor.opr_count(mode);
2972 for (int k = 0; k < n; k++) {
2973 LIR_Opr opr = visitor.opr_at(mode, k);
2974 if (opr->is_virtual_register()) {
2975 visitor.set_opr_at(mode, k, color_lir_opr(opr, op_id, mode));
2976 }
2977 }
2978 }
2979
2980 if (visitor.info_count() > 0) {
2981 // exception handling
2982 if (compilation()->has_exception_handlers()) {
2983 XHandlers* xhandlers = visitor.all_xhandler();
2984 int n = xhandlers->length();
2985 for (int k = 0; k < n; k++) {
2986 XHandler* handler = xhandlers->handler_at(k);
2987 if (handler->entry_code() != nullptr) {
2988 assign_reg_num(handler->entry_code()->instructions_list(), nullptr);
2989 }
2990 }
2991 } else {
2992 assert(visitor.all_xhandler()->length() == 0, "missed exception handler");
2993 }
2994
2995 // compute oop map
2996 assert(iw != nullptr, "needed for compute_oop_map");
2997 compute_oop_map(iw, visitor, op);
2998
2999 // compute debug information
3000 int n = visitor.info_count();
3001 for (int k = 0; k < n; k++) {
3002 compute_debug_info(visitor.info_at(k), op_id);
3003 }
3004 }
3005
3006 #ifdef ASSERT
3007 // make sure we haven't made the op invalid.
3008 op->verify();
3009 #endif
3010
3011 // remove useless moves
3012 if (op->code() == lir_move) {
3013 assert(op->as_Op1() != nullptr, "move must be LIR_Op1");
3014 LIR_Op1* move = (LIR_Op1*)op;
3015 LIR_Opr src = move->in_opr();
3016 LIR_Opr dst = move->result_opr();
3017 if (dst == src ||
3018 (!dst->is_pointer() && !src->is_pointer() &&
3019 src->is_same_register(dst))) {
3020 instructions->at_put(j, nullptr);
3021 has_dead = true;
3022 }
3023 }
3024 }
3025
3026 if (has_dead) {
3027 // iterate all instructions of the block and remove all null-values.
3028 int insert_point = 0;
3029 for (int j = 0; j < num_inst; j++) {
3030 LIR_Op* op = instructions->at(j);
3031 if (op != nullptr) {
3032 if (insert_point != j) {
3033 instructions->at_put(insert_point, op);
3034 }
3035 insert_point++;
3036 }
3037 }
3038 instructions->trunc_to(insert_point);
3039 }
3040 }
3041
3042 void LinearScan::assign_reg_num() {
3043 TIME_LINEAR_SCAN(timer_assign_reg_num);
3044
3045 init_compute_debug_info();
3046 IntervalWalker* iw = init_compute_oop_maps();
3047
3048 int num_blocks = block_count();
3049 for (int i = 0; i < num_blocks; i++) {
3050 BlockBegin* block = block_at(i);
3051 assign_reg_num(block->lir()->instructions_list(), iw);
3052 }
3053 }
3054
3055
3056 void LinearScan::do_linear_scan() {
3057 NOT_PRODUCT(_total_timer.begin_method());
3058
3059 number_instructions();
3060
3061 NOT_PRODUCT(print_lir(1, "Before Register Allocation"));
3062
3063 compute_local_live_sets();
3064 compute_global_live_sets();
3065 CHECK_BAILOUT();
3066
3067 build_intervals();
3068 CHECK_BAILOUT();
3069 sort_intervals_before_allocation();
3070
3071 NOT_PRODUCT(print_intervals("Before Register Allocation"));
3072 NOT_PRODUCT(LinearScanStatistic::compute(this, _stat_before_alloc));
3073
3074 allocate_registers();
3075 CHECK_BAILOUT();
3076
3077 resolve_data_flow();
3078 if (compilation()->has_exception_handlers()) {
3079 resolve_exception_handlers();
3080 }
3081 // fill in number of spill slots into frame_map
3082 propagate_spill_slots();
3083 CHECK_BAILOUT();
3084
3085 NOT_PRODUCT(print_intervals("After Register Allocation"));
3086 NOT_PRODUCT(print_lir(2, "LIR after register allocation:"));
3087
3088 sort_intervals_after_allocation();
3089
3090 DEBUG_ONLY(verify());
3091
3092 eliminate_spill_moves();
3093 assign_reg_num();
3094 CHECK_BAILOUT();
3095
3096 NOT_PRODUCT(print_lir(2, "LIR after assignment of register numbers:"));
3097 NOT_PRODUCT(LinearScanStatistic::compute(this, _stat_after_asign));
3098
3099 #ifndef RISCV
3100 // Disable these optimizations on riscv temporarily, because it does not
3101 // work when the comparison operands are bound to branches or cmoves.
3102 { TIME_LINEAR_SCAN(timer_optimize_lir);
3103
3104 EdgeMoveOptimizer::optimize(ir()->code());
3105 ControlFlowOptimizer::optimize(ir()->code());
3106 // check that cfg is still correct after optimizations
3107 ir()->verify();
3108 }
3109 #endif
3110
3111 NOT_PRODUCT(print_lir(1, "Before Code Generation", false));
3112 NOT_PRODUCT(LinearScanStatistic::compute(this, _stat_final));
3113 NOT_PRODUCT(_total_timer.end_method(this));
3114 }
3115
3116
3117 // ********** Printing functions
3118
3119 #ifndef PRODUCT
3120
3121 void LinearScan::print_timers(double total) {
3122 _total_timer.print(total);
3123 }
3124
3125 void LinearScan::print_statistics() {
3126 _stat_before_alloc.print("before allocation");
3127 _stat_after_asign.print("after assignment of register");
3128 _stat_final.print("after optimization");
3129 }
3130
3131 void LinearScan::print_bitmap(BitMap& b) {
3132 for (unsigned int i = 0; i < b.size(); i++) {
3133 if (b.at(i)) tty->print("%d ", i);
3134 }
3135 tty->cr();
3136 }
3137
3138 void LinearScan::print_intervals(const char* label) {
3139 if (TraceLinearScanLevel >= 1) {
3140 int i;
3141 tty->cr();
3142 tty->print_cr("%s", label);
3143
3144 for (i = 0; i < interval_count(); i++) {
3145 Interval* interval = interval_at(i);
3146 if (interval != nullptr) {
3147 interval->print();
3148 }
3149 }
3150
3151 tty->cr();
3152 tty->print_cr("--- Basic Blocks ---");
3153 for (i = 0; i < block_count(); i++) {
3154 BlockBegin* block = block_at(i);
3155 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());
3156 }
3157 tty->cr();
3158 tty->cr();
3159 }
3160
3161 if (PrintCFGToFile) {
3162 CFGPrinter::print_intervals(&_intervals, label);
3163 }
3164 }
3165
3166 void LinearScan::print_lir(int level, const char* label, bool hir_valid) {
3167 if (TraceLinearScanLevel >= level) {
3168 tty->cr();
3169 tty->print_cr("%s", label);
3170 print_LIR(ir()->linear_scan_order());
3171 tty->cr();
3172 }
3173
3174 if (level == 1 && PrintCFGToFile) {
3175 CFGPrinter::print_cfg(ir()->linear_scan_order(), label, hir_valid, true);
3176 }
3177 }
3178
3179 void LinearScan::print_reg_num(outputStream* out, int reg_num) {
3180 if (reg_num == -1) {
3181 out->print("[ANY]");
3182 return;
3183 } else if (reg_num >= LIR_Opr::vreg_base) {
3184 out->print("[VREG %d]", reg_num);
3185 return;
3186 }
3187
3188 LIR_Opr opr = get_operand(reg_num);
3189 assert(opr->is_valid(), "unknown register");
3190 opr->print(out);
3191 }
3192
3193 LIR_Opr LinearScan::get_operand(int reg_num) {
3194 LIR_Opr opr = LIR_OprFact::illegal();
3195
3196 #ifdef X86
3197 int last_xmm_reg = pd_last_xmm_reg;
3198 #ifdef _LP64
3199 if (UseAVX < 3) {
3200 last_xmm_reg = pd_first_xmm_reg + (pd_nof_xmm_regs_frame_map / 2) - 1;
3201 }
3202 #endif
3203 #endif
3204 if (reg_num >= pd_first_cpu_reg && reg_num <= pd_last_cpu_reg) {
3205 opr = LIR_OprFact::single_cpu(reg_num);
3206 } else if (reg_num >= pd_first_fpu_reg && reg_num <= pd_last_fpu_reg) {
3207 opr = LIR_OprFact::single_fpu(reg_num - pd_first_fpu_reg);
3208 #ifdef X86
3209 } else if (reg_num >= pd_first_xmm_reg && reg_num <= last_xmm_reg) {
3210 opr = LIR_OprFact::single_xmm(reg_num - pd_first_xmm_reg);
3211 #endif
3212 } else {
3213 // reg_num == -1 or a virtual register, return the illegal operand
3214 }
3215 return opr;
3216 }
3217
3218 Interval* LinearScan::find_interval_at(int reg_num) const {
3219 if (reg_num < 0 || reg_num >= _intervals.length()) {
3220 return nullptr;
3221 }
3222 return interval_at(reg_num);
3223 }
3224
3225 #endif // PRODUCT
3226
3227
3228 // ********** verification functions for allocation
3229 // (check that all intervals have a correct register and that no registers are overwritten)
3230 #ifdef ASSERT
3231
3232 void LinearScan::verify() {
3233 TRACE_LINEAR_SCAN(2, tty->print_cr("********* verifying intervals ******************************************"));
3234 verify_intervals();
3235
3236 TRACE_LINEAR_SCAN(2, tty->print_cr("********* verifying that no oops are in fixed intervals ****************"));
3237 verify_no_oops_in_fixed_intervals();
3238
3239 TRACE_LINEAR_SCAN(2, tty->print_cr("********* verifying that unpinned constants are not alive across block boundaries"));
3240 verify_constants();
3241
3242 TRACE_LINEAR_SCAN(2, tty->print_cr("********* verifying register allocation ********************************"));
3243 verify_registers();
3244
3245 TRACE_LINEAR_SCAN(2, tty->print_cr("********* no errors found **********************************************"));
3246 }
3247
3248 void LinearScan::verify_intervals() {
3249 int len = interval_count();
3250 bool has_error = false;
3251
3252 for (int i = 0; i < len; i++) {
3253 Interval* i1 = interval_at(i);
3254 if (i1 == nullptr) continue;
3255
3256 i1->check_split_children();
3257
3258 if (i1->reg_num() != i) {
3259 tty->print_cr("Interval %d is on position %d in list", i1->reg_num(), i); i1->print(); tty->cr();
3260 has_error = true;
3261 }
3262
3263 if (i1->reg_num() >= LIR_Opr::vreg_base && i1->type() == T_ILLEGAL) {
3264 tty->print_cr("Interval %d has no type assigned", i1->reg_num()); i1->print(); tty->cr();
3265 has_error = true;
3266 }
3267
3268 if (i1->assigned_reg() == any_reg) {
3269 tty->print_cr("Interval %d has no register assigned", i1->reg_num()); i1->print(); tty->cr();
3270 has_error = true;
3271 }
3272
3273 if (i1->assigned_reg() == i1->assigned_regHi()) {
3274 tty->print_cr("Interval %d: low and high register equal", i1->reg_num()); i1->print(); tty->cr();
3275 has_error = true;
3276 }
3277
3278 if (!is_processed_reg_num(i1->assigned_reg())) {
3279 tty->print_cr("Can not have an Interval for an ignored register"); i1->print(); tty->cr();
3280 has_error = true;
3281 }
3282
3283 // special intervals that are created in MoveResolver
3284 // -> ignore them because the range information has no meaning there
3285 if (i1->from() == 1 && i1->to() == 2) continue;
3286
3287 if (i1->first() == Range::end()) {
3288 tty->print_cr("Interval %d has no Range", i1->reg_num()); i1->print(); tty->cr();
3289 has_error = true;
3290 }
3291
3292 for (Range* r = i1->first(); r != Range::end(); r = r->next()) {
3293 if (r->from() >= r->to()) {
3294 tty->print_cr("Interval %d has zero length range", i1->reg_num()); i1->print(); tty->cr();
3295 has_error = true;
3296 }
3297 }
3298
3299 for (int j = i + 1; j < len; j++) {
3300 Interval* i2 = interval_at(j);
3301 if (i2 == nullptr || (i2->from() == 1 && i2->to() == 2)) continue;
3302
3303 int r1 = i1->assigned_reg();
3304 int r1Hi = i1->assigned_regHi();
3305 int r2 = i2->assigned_reg();
3306 int r2Hi = i2->assigned_regHi();
3307 if ((r1 == r2 || r1 == r2Hi || (r1Hi != any_reg && (r1Hi == r2 || r1Hi == r2Hi))) && i1->intersects(i2)) {
3308 tty->print_cr("Intervals %d and %d overlap and have the same register assigned", i1->reg_num(), i2->reg_num());
3309 i1->print(); tty->cr();
3310 i2->print(); tty->cr();
3311 has_error = true;
3312 }
3313 }
3314 }
3315
3316 assert(has_error == false, "register allocation invalid");
3317 }
3318
3319
3320 void LinearScan::verify_no_oops_in_fixed_intervals() {
3321 Interval* fixed_intervals;
3322 Interval* other_intervals;
3323 create_unhandled_lists(&fixed_intervals, &other_intervals, is_precolored_cpu_interval, nullptr);
3324
3325 // to ensure a walking until the last instruction id, add a dummy interval
3326 // with a high operation id
3327 other_intervals = new Interval(any_reg);
3328 other_intervals->add_range(max_jint - 2, max_jint - 1);
3329 IntervalWalker* iw = new IntervalWalker(this, fixed_intervals, other_intervals);
3330
3331 LIR_OpVisitState visitor;
3332 for (int i = 0; i < block_count(); i++) {
3333 BlockBegin* block = block_at(i);
3334
3335 LIR_OpList* instructions = block->lir()->instructions_list();
3336
3337 for (int j = 0; j < instructions->length(); j++) {
3338 LIR_Op* op = instructions->at(j);
3339 int op_id = op->id();
3340
3341 visitor.visit(op);
3342
3343 if (visitor.info_count() > 0) {
3344 iw->walk_before(op->id());
3345 bool check_live = true;
3346 if (op->code() == lir_move) {
3347 LIR_Op1* move = (LIR_Op1*)op;
3348 check_live = (move->patch_code() == lir_patch_none);
3349 }
3350 LIR_OpBranch* branch = op->as_OpBranch();
3351 if (branch != nullptr && branch->stub() != nullptr && branch->stub()->is_exception_throw_stub()) {
3352 // Don't bother checking the stub in this case since the
3353 // exception stub will never return to normal control flow.
3354 check_live = false;
3355 }
3356
3357 // Make sure none of the fixed registers is live across an
3358 // oopmap since we can't handle that correctly.
3359 if (check_live) {
3360 for (Interval* interval = iw->active_first(fixedKind);
3361 interval != Interval::end();
3362 interval = interval->next()) {
3363 if (interval->current_to() > op->id() + 1) {
3364 // This interval is live out of this op so make sure
3365 // that this interval represents some value that's
3366 // referenced by this op either as an input or output.
3367 bool ok = false;
3368 for_each_visitor_mode(mode) {
3369 int n = visitor.opr_count(mode);
3370 for (int k = 0; k < n; k++) {
3371 LIR_Opr opr = visitor.opr_at(mode, k);
3372 if (opr->is_fixed_cpu()) {
3373 if (interval_at(reg_num(opr)) == interval) {
3374 ok = true;
3375 break;
3376 }
3377 int hi = reg_numHi(opr);
3378 if (hi != -1 && interval_at(hi) == interval) {
3379 ok = true;
3380 break;
3381 }
3382 }
3383 }
3384 }
3385 assert(ok, "fixed intervals should never be live across an oopmap point");
3386 }
3387 }
3388 }
3389 }
3390
3391 // oop-maps at calls do not contain registers, so check is not needed
3392 if (!visitor.has_call()) {
3393
3394 for_each_visitor_mode(mode) {
3395 int n = visitor.opr_count(mode);
3396 for (int k = 0; k < n; k++) {
3397 LIR_Opr opr = visitor.opr_at(mode, k);
3398
3399 if (opr->is_fixed_cpu() && opr->is_oop()) {
3400 // operand is a non-virtual cpu register and contains an oop
3401 TRACE_LINEAR_SCAN(4, op->print_on(tty); tty->print("checking operand "); opr->print(); tty->cr());
3402
3403 Interval* interval = interval_at(reg_num(opr));
3404 assert(interval != nullptr, "no interval");
3405
3406 if (mode == LIR_OpVisitState::inputMode) {
3407 if (interval->to() >= op_id + 1) {
3408 assert(interval->to() < op_id + 2 ||
3409 interval->has_hole_between(op_id, op_id + 2),
3410 "oop input operand live after instruction");
3411 }
3412 } else if (mode == LIR_OpVisitState::outputMode) {
3413 if (interval->from() <= op_id - 1) {
3414 assert(interval->has_hole_between(op_id - 1, op_id),
3415 "oop input operand live after instruction");
3416 }
3417 }
3418 }
3419 }
3420 }
3421 }
3422 }
3423 }
3424 }
3425
3426
3427 void LinearScan::verify_constants() {
3428 int num_regs = num_virtual_regs();
3429 int size = live_set_size();
3430 int num_blocks = block_count();
3431
3432 for (int i = 0; i < num_blocks; i++) {
3433 BlockBegin* block = block_at(i);
3434 ResourceBitMap& live_at_edge = block->live_in();
3435
3436 // visit all registers where the live_at_edge bit is set
3437 auto visitor = [&](BitMap::idx_t index) {
3438 int r = static_cast<int>(index);
3439 TRACE_LINEAR_SCAN(4, tty->print("checking interval %d of block B%d", r, block->block_id()));
3440
3441 Value value = gen()->instruction_for_vreg(r);
3442
3443 assert(value != nullptr, "all intervals live across block boundaries must have Value");
3444 assert(value->operand()->is_register() && value->operand()->is_virtual(), "value must have virtual operand");
3445 assert(value->operand()->vreg_number() == r, "register number must match");
3446 // TKR assert(value->as_Constant() == nullptr || value->is_pinned(), "only pinned constants can be alive across block boundaries");
3447 };
3448 live_at_edge.iterate(visitor, 0, size);
3449 }
3450 }
3451
3452
3453 class RegisterVerifier: public StackObj {
3454 private:
3455 LinearScan* _allocator;
3456 BlockList _work_list; // all blocks that must be processed
3457 IntervalsList _saved_states; // saved information of previous check
3458
3459 // simplified access to methods of LinearScan
3460 Compilation* compilation() const { return _allocator->compilation(); }
3461 Interval* interval_at(int reg_num) const { return _allocator->interval_at(reg_num); }
3462 int reg_num(LIR_Opr opr) const { return _allocator->reg_num(opr); }
3463
3464 // currently, only registers are processed
3465 int state_size() { return LinearScan::nof_regs; }
3466
3467 // accessors
3468 IntervalList* state_for_block(BlockBegin* block) { return _saved_states.at(block->block_id()); }
3469 void set_state_for_block(BlockBegin* block, IntervalList* saved_state) { _saved_states.at_put(block->block_id(), saved_state); }
3470 void add_to_work_list(BlockBegin* block) { if (!_work_list.contains(block)) _work_list.append(block); }
3471
3472 // helper functions
3473 IntervalList* copy(IntervalList* input_state);
3474 void state_put(IntervalList* input_state, int reg, Interval* interval);
3475 bool check_state(IntervalList* input_state, int reg, Interval* interval);
3476
3477 void process_block(BlockBegin* block);
3478 void process_xhandler(XHandler* xhandler, IntervalList* input_state);
3479 void process_successor(BlockBegin* block, IntervalList* input_state);
3480 void process_operations(LIR_List* ops, IntervalList* input_state);
3481
3482 public:
3483 RegisterVerifier(LinearScan* allocator)
3484 : _allocator(allocator)
3485 , _work_list(16)
3486 , _saved_states(BlockBegin::number_of_blocks(), BlockBegin::number_of_blocks(), nullptr)
3487 { }
3488
3489 void verify(BlockBegin* start);
3490 };
3491
3492
3493 // entry function from LinearScan that starts the verification
3494 void LinearScan::verify_registers() {
3495 RegisterVerifier verifier(this);
3496 verifier.verify(block_at(0));
3497 }
3498
3499
3500 void RegisterVerifier::verify(BlockBegin* start) {
3501 // setup input registers (method arguments) for first block
3502 int input_state_len = state_size();
3503 IntervalList* input_state = new IntervalList(input_state_len, input_state_len, nullptr);
3504 CallingConvention* args = compilation()->frame_map()->incoming_arguments();
3505 for (int n = 0; n < args->length(); n++) {
3506 LIR_Opr opr = args->at(n);
3507 if (opr->is_register()) {
3508 Interval* interval = interval_at(reg_num(opr));
3509
3510 if (interval->assigned_reg() < state_size()) {
3511 input_state->at_put(interval->assigned_reg(), interval);
3512 }
3513 if (interval->assigned_regHi() != LinearScan::any_reg && interval->assigned_regHi() < state_size()) {
3514 input_state->at_put(interval->assigned_regHi(), interval);
3515 }
3516 }
3517 }
3518
3519 set_state_for_block(start, input_state);
3520 add_to_work_list(start);
3521
3522 // main loop for verification
3523 do {
3524 BlockBegin* block = _work_list.at(0);
3525 _work_list.remove_at(0);
3526
3527 process_block(block);
3528 } while (!_work_list.is_empty());
3529 }
3530
3531 void RegisterVerifier::process_block(BlockBegin* block) {
3532 TRACE_LINEAR_SCAN(2, tty->cr(); tty->print_cr("process_block B%d", block->block_id()));
3533
3534 // must copy state because it is modified
3535 IntervalList* input_state = copy(state_for_block(block));
3536
3537 if (TraceLinearScanLevel >= 4) {
3538 tty->print_cr("Input-State of intervals:");
3539 tty->print(" ");
3540 for (int i = 0; i < state_size(); i++) {
3541 if (input_state->at(i) != nullptr) {
3542 tty->print(" %4d", input_state->at(i)->reg_num());
3543 } else {
3544 tty->print(" __");
3545 }
3546 }
3547 tty->cr();
3548 tty->cr();
3549 }
3550
3551 // process all operations of the block
3552 process_operations(block->lir(), input_state);
3553
3554 // iterate all successors
3555 for (int i = 0; i < block->number_of_sux(); i++) {
3556 process_successor(block->sux_at(i), input_state);
3557 }
3558 }
3559
3560 void RegisterVerifier::process_xhandler(XHandler* xhandler, IntervalList* input_state) {
3561 TRACE_LINEAR_SCAN(2, tty->print_cr("process_xhandler B%d", xhandler->entry_block()->block_id()));
3562
3563 // must copy state because it is modified
3564 input_state = copy(input_state);
3565
3566 if (xhandler->entry_code() != nullptr) {
3567 process_operations(xhandler->entry_code(), input_state);
3568 }
3569 process_successor(xhandler->entry_block(), input_state);
3570 }
3571
3572 void RegisterVerifier::process_successor(BlockBegin* block, IntervalList* input_state) {
3573 IntervalList* saved_state = state_for_block(block);
3574
3575 if (saved_state != nullptr) {
3576 // this block was already processed before.
3577 // check if new input_state is consistent with saved_state
3578
3579 bool saved_state_correct = true;
3580 for (int i = 0; i < state_size(); i++) {
3581 if (input_state->at(i) != saved_state->at(i)) {
3582 // current input_state and previous saved_state assume a different
3583 // interval in this register -> assume that this register is invalid
3584 if (saved_state->at(i) != nullptr) {
3585 // invalidate old calculation only if it assumed that
3586 // register was valid. when the register was already invalid,
3587 // then the old calculation was correct.
3588 saved_state_correct = false;
3589 saved_state->at_put(i, nullptr);
3590
3591 TRACE_LINEAR_SCAN(4, tty->print_cr("process_successor B%d: invalidating slot %d", block->block_id(), i));
3592 }
3593 }
3594 }
3595
3596 if (saved_state_correct) {
3597 // already processed block with correct input_state
3598 TRACE_LINEAR_SCAN(2, tty->print_cr("process_successor B%d: previous visit already correct", block->block_id()));
3599 } else {
3600 // must re-visit this block
3601 TRACE_LINEAR_SCAN(2, tty->print_cr("process_successor B%d: must re-visit because input state changed", block->block_id()));
3602 add_to_work_list(block);
3603 }
3604
3605 } else {
3606 // block was not processed before, so set initial input_state
3607 TRACE_LINEAR_SCAN(2, tty->print_cr("process_successor B%d: initial visit", block->block_id()));
3608
3609 set_state_for_block(block, copy(input_state));
3610 add_to_work_list(block);
3611 }
3612 }
3613
3614
3615 IntervalList* RegisterVerifier::copy(IntervalList* input_state) {
3616 IntervalList* copy_state = new IntervalList(input_state->length());
3617 copy_state->appendAll(input_state);
3618 return copy_state;
3619 }
3620
3621 void RegisterVerifier::state_put(IntervalList* input_state, int reg, Interval* interval) {
3622 if (reg != LinearScan::any_reg && reg < state_size()) {
3623 if (interval != nullptr) {
3624 TRACE_LINEAR_SCAN(4, tty->print_cr(" reg[%d] = %d", reg, interval->reg_num()));
3625 } else if (input_state->at(reg) != nullptr) {
3626 TRACE_LINEAR_SCAN(4, tty->print_cr(" reg[%d] = null", reg));
3627 }
3628
3629 input_state->at_put(reg, interval);
3630 }
3631 }
3632
3633 bool RegisterVerifier::check_state(IntervalList* input_state, int reg, Interval* interval) {
3634 if (reg != LinearScan::any_reg && reg < state_size()) {
3635 if (input_state->at(reg) != interval) {
3636 tty->print_cr("!! Error in register allocation: register %d does not contain interval %d", reg, interval->reg_num());
3637 return true;
3638 }
3639 }
3640 return false;
3641 }
3642
3643 void RegisterVerifier::process_operations(LIR_List* ops, IntervalList* input_state) {
3644 // visit all instructions of the block
3645 LIR_OpVisitState visitor;
3646 bool has_error = false;
3647
3648 for (int i = 0; i < ops->length(); i++) {
3649 LIR_Op* op = ops->at(i);
3650 visitor.visit(op);
3651
3652 TRACE_LINEAR_SCAN(4, op->print_on(tty));
3653
3654 // check if input operands are correct
3655 int j;
3656 int n = visitor.opr_count(LIR_OpVisitState::inputMode);
3657 for (j = 0; j < n; j++) {
3658 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::inputMode, j);
3659 if (opr->is_register() && LinearScan::is_processed_reg_num(reg_num(opr))) {
3660 Interval* interval = interval_at(reg_num(opr));
3661 if (op->id() != -1) {
3662 interval = interval->split_child_at_op_id(op->id(), LIR_OpVisitState::inputMode);
3663 }
3664
3665 has_error |= check_state(input_state, interval->assigned_reg(), interval->split_parent());
3666 has_error |= check_state(input_state, interval->assigned_regHi(), interval->split_parent());
3667
3668 // When an operand is marked with is_last_use, then the fpu stack allocator
3669 // removes the register from the fpu stack -> the register contains no value
3670 if (opr->is_last_use()) {
3671 state_put(input_state, interval->assigned_reg(), nullptr);
3672 state_put(input_state, interval->assigned_regHi(), nullptr);
3673 }
3674 }
3675 }
3676
3677 // invalidate all caller save registers at calls
3678 if (visitor.has_call()) {
3679 for (j = 0; j < FrameMap::nof_caller_save_cpu_regs(); j++) {
3680 state_put(input_state, reg_num(FrameMap::caller_save_cpu_reg_at(j)), nullptr);
3681 }
3682 for (j = 0; j < FrameMap::nof_caller_save_fpu_regs; j++) {
3683 state_put(input_state, reg_num(FrameMap::caller_save_fpu_reg_at(j)), nullptr);
3684 }
3685
3686 #ifdef X86
3687 int num_caller_save_xmm_regs = FrameMap::get_num_caller_save_xmms();
3688 for (j = 0; j < num_caller_save_xmm_regs; j++) {
3689 state_put(input_state, reg_num(FrameMap::caller_save_xmm_reg_at(j)), nullptr);
3690 }
3691 #endif
3692 }
3693
3694 // process xhandler before output and temp operands
3695 XHandlers* xhandlers = visitor.all_xhandler();
3696 n = xhandlers->length();
3697 for (int k = 0; k < n; k++) {
3698 process_xhandler(xhandlers->handler_at(k), input_state);
3699 }
3700
3701 // set temp operands (some operations use temp operands also as output operands, so can't set them null)
3702 n = visitor.opr_count(LIR_OpVisitState::tempMode);
3703 for (j = 0; j < n; j++) {
3704 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::tempMode, j);
3705 if (opr->is_register() && LinearScan::is_processed_reg_num(reg_num(opr))) {
3706 Interval* interval = interval_at(reg_num(opr));
3707 if (op->id() != -1) {
3708 interval = interval->split_child_at_op_id(op->id(), LIR_OpVisitState::tempMode);
3709 }
3710
3711 state_put(input_state, interval->assigned_reg(), interval->split_parent());
3712 state_put(input_state, interval->assigned_regHi(), interval->split_parent());
3713 }
3714 }
3715
3716 // set output operands
3717 n = visitor.opr_count(LIR_OpVisitState::outputMode);
3718 for (j = 0; j < n; j++) {
3719 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::outputMode, j);
3720 if (opr->is_register() && LinearScan::is_processed_reg_num(reg_num(opr))) {
3721 Interval* interval = interval_at(reg_num(opr));
3722 if (op->id() != -1) {
3723 interval = interval->split_child_at_op_id(op->id(), LIR_OpVisitState::outputMode);
3724 }
3725
3726 state_put(input_state, interval->assigned_reg(), interval->split_parent());
3727 state_put(input_state, interval->assigned_regHi(), interval->split_parent());
3728 }
3729 }
3730 }
3731 assert(has_error == false, "Error in register allocation");
3732 }
3733
3734 #endif // ASSERT
3735
3736
3737
3738 // **** Implementation of MoveResolver ******************************
3739
3740 MoveResolver::MoveResolver(LinearScan* allocator) :
3741 _allocator(allocator),
3742 _insert_list(nullptr),
3743 _insert_idx(-1),
3744 _insertion_buffer(),
3745 _mapping_from(8),
3746 _mapping_from_opr(8),
3747 _mapping_to(8),
3748 _multiple_reads_allowed(false)
3749 {
3750 for (int i = 0; i < LinearScan::nof_regs; i++) {
3751 _register_blocked[i] = 0;
3752 }
3753 DEBUG_ONLY(check_empty());
3754 }
3755
3756
3757 #ifdef ASSERT
3758
3759 void MoveResolver::check_empty() {
3760 assert(_mapping_from.length() == 0 && _mapping_from_opr.length() == 0 && _mapping_to.length() == 0, "list must be empty before and after processing");
3761 for (int i = 0; i < LinearScan::nof_regs; i++) {
3762 assert(register_blocked(i) == 0, "register map must be empty before and after processing");
3763 }
3764 assert(_multiple_reads_allowed == false, "must have default value");
3765 }
3766
3767 void MoveResolver::verify_before_resolve() {
3768 assert(_mapping_from.length() == _mapping_from_opr.length(), "length must be equal");
3769 assert(_mapping_from.length() == _mapping_to.length(), "length must be equal");
3770 assert(_insert_list != nullptr && _insert_idx != -1, "insert position not set");
3771
3772 int i, j;
3773 if (!_multiple_reads_allowed) {
3774 for (i = 0; i < _mapping_from.length(); i++) {
3775 for (j = i + 1; j < _mapping_from.length(); j++) {
3776 assert(_mapping_from.at(i) == nullptr || _mapping_from.at(i) != _mapping_from.at(j), "cannot read from same interval twice");
3777 }
3778 }
3779 }
3780
3781 for (i = 0; i < _mapping_to.length(); i++) {
3782 for (j = i + 1; j < _mapping_to.length(); j++) {
3783 assert(_mapping_to.at(i) != _mapping_to.at(j), "cannot write to same interval twice");
3784 }
3785 }
3786
3787
3788 ResourceBitMap used_regs(LinearScan::nof_regs + allocator()->frame_map()->argcount() + allocator()->max_spills());
3789 if (!_multiple_reads_allowed) {
3790 for (i = 0; i < _mapping_from.length(); i++) {
3791 Interval* it = _mapping_from.at(i);
3792 if (it != nullptr) {
3793 assert(!used_regs.at(it->assigned_reg()), "cannot read from same register twice");
3794 used_regs.set_bit(it->assigned_reg());
3795
3796 if (it->assigned_regHi() != LinearScan::any_reg) {
3797 assert(!used_regs.at(it->assigned_regHi()), "cannot read from same register twice");
3798 used_regs.set_bit(it->assigned_regHi());
3799 }
3800 }
3801 }
3802 }
3803
3804 used_regs.clear();
3805 for (i = 0; i < _mapping_to.length(); i++) {
3806 Interval* it = _mapping_to.at(i);
3807 assert(!used_regs.at(it->assigned_reg()), "cannot write to same register twice");
3808 used_regs.set_bit(it->assigned_reg());
3809
3810 if (it->assigned_regHi() != LinearScan::any_reg) {
3811 assert(!used_regs.at(it->assigned_regHi()), "cannot write to same register twice");
3812 used_regs.set_bit(it->assigned_regHi());
3813 }
3814 }
3815
3816 used_regs.clear();
3817 for (i = 0; i < _mapping_from.length(); i++) {
3818 Interval* it = _mapping_from.at(i);
3819 if (it != nullptr && it->assigned_reg() >= LinearScan::nof_regs) {
3820 used_regs.set_bit(it->assigned_reg());
3821 }
3822 }
3823 for (i = 0; i < _mapping_to.length(); i++) {
3824 Interval* it = _mapping_to.at(i);
3825 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");
3826 }
3827 }
3828
3829 #endif // ASSERT
3830
3831
3832 // mark assigned_reg and assigned_regHi of the interval as blocked
3833 void MoveResolver::block_registers(Interval* it) {
3834 int reg = it->assigned_reg();
3835 if (reg < LinearScan::nof_regs) {
3836 assert(_multiple_reads_allowed || register_blocked(reg) == 0, "register already marked as used");
3837 set_register_blocked(reg, 1);
3838 }
3839 reg = it->assigned_regHi();
3840 if (reg != LinearScan::any_reg && reg < LinearScan::nof_regs) {
3841 assert(_multiple_reads_allowed || register_blocked(reg) == 0, "register already marked as used");
3842 set_register_blocked(reg, 1);
3843 }
3844 }
3845
3846 // mark assigned_reg and assigned_regHi of the interval as unblocked
3847 void MoveResolver::unblock_registers(Interval* it) {
3848 int reg = it->assigned_reg();
3849 if (reg < LinearScan::nof_regs) {
3850 assert(register_blocked(reg) > 0, "register already marked as unused");
3851 set_register_blocked(reg, -1);
3852 }
3853 reg = it->assigned_regHi();
3854 if (reg != LinearScan::any_reg && reg < LinearScan::nof_regs) {
3855 assert(register_blocked(reg) > 0, "register already marked as unused");
3856 set_register_blocked(reg, -1);
3857 }
3858 }
3859
3860 // check if assigned_reg and assigned_regHi of the to-interval are not blocked (or only blocked by from)
3861 bool MoveResolver::save_to_process_move(Interval* from, Interval* to) {
3862 int from_reg = -1;
3863 int from_regHi = -1;
3864 if (from != nullptr) {
3865 from_reg = from->assigned_reg();
3866 from_regHi = from->assigned_regHi();
3867 }
3868
3869 int reg = to->assigned_reg();
3870 if (reg < LinearScan::nof_regs) {
3871 if (register_blocked(reg) > 1 || (register_blocked(reg) == 1 && reg != from_reg && reg != from_regHi)) {
3872 return false;
3873 }
3874 }
3875 reg = to->assigned_regHi();
3876 if (reg != LinearScan::any_reg && reg < LinearScan::nof_regs) {
3877 if (register_blocked(reg) > 1 || (register_blocked(reg) == 1 && reg != from_reg && reg != from_regHi)) {
3878 return false;
3879 }
3880 }
3881
3882 return true;
3883 }
3884
3885
3886 void MoveResolver::create_insertion_buffer(LIR_List* list) {
3887 assert(!_insertion_buffer.initialized(), "overwriting existing buffer");
3888 _insertion_buffer.init(list);
3889 }
3890
3891 void MoveResolver::append_insertion_buffer() {
3892 if (_insertion_buffer.initialized()) {
3893 _insertion_buffer.lir_list()->append(&_insertion_buffer);
3894 }
3895 assert(!_insertion_buffer.initialized(), "must be uninitialized now");
3896
3897 _insert_list = nullptr;
3898 _insert_idx = -1;
3899 }
3900
3901 void MoveResolver::insert_move(Interval* from_interval, Interval* to_interval) {
3902 assert(from_interval->reg_num() != to_interval->reg_num(), "from and to interval equal");
3903 assert(from_interval->type() == to_interval->type(), "move between different types");
3904 assert(_insert_list != nullptr && _insert_idx != -1, "must setup insert position first");
3905 assert(_insertion_buffer.lir_list() == _insert_list, "wrong insertion buffer");
3906
3907 LIR_Opr from_opr = get_virtual_register(from_interval);
3908 LIR_Opr to_opr = get_virtual_register(to_interval);
3909
3910 if (!_multiple_reads_allowed) {
3911 // the last_use flag is an optimization for FPU stack allocation. When the same
3912 // input interval is used in more than one move, then it is too difficult to determine
3913 // if this move is really the last use.
3914 from_opr = from_opr->make_last_use();
3915 }
3916 _insertion_buffer.move(_insert_idx, from_opr, to_opr);
3917
3918 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()));
3919 }
3920
3921 void MoveResolver::insert_move(LIR_Opr from_opr, Interval* to_interval) {
3922 assert(from_opr->type() == to_interval->type(), "move between different types");
3923 assert(_insert_list != nullptr && _insert_idx != -1, "must setup insert position first");
3924 assert(_insertion_buffer.lir_list() == _insert_list, "wrong insertion buffer");
3925
3926 LIR_Opr to_opr = get_virtual_register(to_interval);
3927 _insertion_buffer.move(_insert_idx, from_opr, to_opr);
3928
3929 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()));
3930 }
3931
3932 LIR_Opr MoveResolver::get_virtual_register(Interval* interval) {
3933 // Add a little fudge factor for the bailout since the bailout is only checked periodically. This allows us to hand out
3934 // a few extra registers before we really run out which helps to avoid to trip over assertions.
3935 int reg_num = interval->reg_num();
3936 if (reg_num + 20 >= LIR_Opr::vreg_max) {
3937 _allocator->bailout("out of virtual registers in linear scan");
3938 if (reg_num + 2 >= LIR_Opr::vreg_max) {
3939 // Wrap it around and continue until bailout really happens to avoid hitting assertions.
3940 reg_num = LIR_Opr::vreg_base;
3941 }
3942 }
3943 LIR_Opr vreg = LIR_OprFact::virtual_register(reg_num, interval->type());
3944 assert(vreg != LIR_OprFact::illegal(), "ran out of virtual registers");
3945 return vreg;
3946 }
3947
3948 void MoveResolver::resolve_mappings() {
3949 TRACE_LINEAR_SCAN(4, tty->print_cr("MoveResolver: resolving mappings for Block B%d, index %d", _insert_list->block() != nullptr ? _insert_list->block()->block_id() : -1, _insert_idx));
3950 DEBUG_ONLY(verify_before_resolve());
3951
3952 // Block all registers that are used as input operands of a move.
3953 // When a register is blocked, no move to this register is emitted.
3954 // This is necessary for detecting cycles in moves.
3955 int i;
3956 for (i = _mapping_from.length() - 1; i >= 0; i--) {
3957 Interval* from_interval = _mapping_from.at(i);
3958 if (from_interval != nullptr) {
3959 block_registers(from_interval);
3960 }
3961 }
3962
3963 int spill_candidate = -1;
3964 while (_mapping_from.length() > 0) {
3965 bool processed_interval = false;
3966
3967 for (i = _mapping_from.length() - 1; i >= 0; i--) {
3968 Interval* from_interval = _mapping_from.at(i);
3969 Interval* to_interval = _mapping_to.at(i);
3970
3971 if (save_to_process_move(from_interval, to_interval)) {
3972 // this interval can be processed because target is free
3973 if (from_interval != nullptr) {
3974 insert_move(from_interval, to_interval);
3975 unblock_registers(from_interval);
3976 } else {
3977 insert_move(_mapping_from_opr.at(i), to_interval);
3978 }
3979 _mapping_from.remove_at(i);
3980 _mapping_from_opr.remove_at(i);
3981 _mapping_to.remove_at(i);
3982
3983 processed_interval = true;
3984 } else if (from_interval != nullptr && from_interval->assigned_reg() < LinearScan::nof_regs) {
3985 // this interval cannot be processed now because target is not free
3986 // it starts in a register, so it is a possible candidate for spilling
3987 spill_candidate = i;
3988 }
3989 }
3990
3991 if (!processed_interval) {
3992 // no move could be processed because there is a cycle in the move list
3993 // (e.g. r1 -> r2, r2 -> r1), so one interval must be spilled to memory
3994 guarantee(spill_candidate != -1, "no interval in register for spilling found");
3995
3996 // create a new spill interval and assign a stack slot to it
3997 Interval* from_interval = _mapping_from.at(spill_candidate);
3998 Interval* spill_interval = new Interval(-1);
3999 spill_interval->set_type(from_interval->type());
4000
4001 // add a dummy range because real position is difficult to calculate
4002 // Note: this range is a special case when the integrity of the allocation is checked
4003 spill_interval->add_range(1, 2);
4004
4005 // do not allocate a new spill slot for temporary interval, but
4006 // use spill slot assigned to from_interval. Otherwise moves from
4007 // one stack slot to another can happen (not allowed by LIR_Assembler
4008 int spill_slot = from_interval->canonical_spill_slot();
4009 if (spill_slot < 0) {
4010 spill_slot = allocator()->allocate_spill_slot(type2spill_size[spill_interval->type()] == 2);
4011 from_interval->set_canonical_spill_slot(spill_slot);
4012 }
4013 spill_interval->assign_reg(spill_slot);
4014 allocator()->append_interval(spill_interval);
4015
4016 TRACE_LINEAR_SCAN(4, tty->print_cr("created new Interval %d for spilling", spill_interval->reg_num()));
4017
4018 // insert a move from register to stack and update the mapping
4019 insert_move(from_interval, spill_interval);
4020 _mapping_from.at_put(spill_candidate, spill_interval);
4021 unblock_registers(from_interval);
4022 }
4023 }
4024
4025 // reset to default value
4026 _multiple_reads_allowed = false;
4027
4028 // check that all intervals have been processed
4029 DEBUG_ONLY(check_empty());
4030 }
4031
4032
4033 void MoveResolver::set_insert_position(LIR_List* insert_list, int insert_idx) {
4034 TRACE_LINEAR_SCAN(4, tty->print_cr("MoveResolver: setting insert position to Block B%d, index %d", insert_list->block() != nullptr ? insert_list->block()->block_id() : -1, insert_idx));
4035 assert(_insert_list == nullptr && _insert_idx == -1, "use move_insert_position instead of set_insert_position when data already set");
4036
4037 create_insertion_buffer(insert_list);
4038 _insert_list = insert_list;
4039 _insert_idx = insert_idx;
4040 }
4041
4042 void MoveResolver::move_insert_position(LIR_List* insert_list, int insert_idx) {
4043 TRACE_LINEAR_SCAN(4, tty->print_cr("MoveResolver: moving insert position to Block B%d, index %d", insert_list->block() != nullptr ? insert_list->block()->block_id() : -1, insert_idx));
4044
4045 if (_insert_list != nullptr && (insert_list != _insert_list || insert_idx != _insert_idx)) {
4046 // insert position changed -> resolve current mappings
4047 resolve_mappings();
4048 }
4049
4050 if (insert_list != _insert_list) {
4051 // block changed -> append insertion_buffer because it is
4052 // bound to a specific block and create a new insertion_buffer
4053 append_insertion_buffer();
4054 create_insertion_buffer(insert_list);
4055 }
4056
4057 _insert_list = insert_list;
4058 _insert_idx = insert_idx;
4059 }
4060
4061 void MoveResolver::add_mapping(Interval* from_interval, Interval* to_interval) {
4062 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()));
4063
4064 _mapping_from.append(from_interval);
4065 _mapping_from_opr.append(LIR_OprFact::illegalOpr);
4066 _mapping_to.append(to_interval);
4067 }
4068
4069
4070 void MoveResolver::add_mapping(LIR_Opr from_opr, Interval* to_interval) {
4071 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()));
4072 assert(from_opr->is_constant(), "only for constants");
4073
4074 _mapping_from.append(nullptr);
4075 _mapping_from_opr.append(from_opr);
4076 _mapping_to.append(to_interval);
4077 }
4078
4079 void MoveResolver::resolve_and_append_moves() {
4080 if (has_mappings()) {
4081 resolve_mappings();
4082 }
4083 append_insertion_buffer();
4084 }
4085
4086
4087
4088 // **** Implementation of Range *************************************
4089
4090 Range::Range(int from, int to, Range* next) :
4091 _from(from),
4092 _to(to),
4093 _next(next)
4094 {
4095 }
4096
4097 // initialize sentinel
4098 Range* Range::_end = nullptr;
4099 void Range::initialize() {
4100 assert(_end == nullptr, "Range initialized more than once");
4101 alignas(Range) static uint8_t end_storage[sizeof(Range)];
4102 _end = ::new(static_cast<void*>(end_storage)) Range(max_jint, max_jint, nullptr);
4103 }
4104
4105 int Range::intersects_at(Range* r2) const {
4106 const Range* r1 = this;
4107
4108 assert(r1 != nullptr && r2 != nullptr, "null ranges not allowed");
4109 assert(r1 != _end && r2 != _end, "empty ranges not allowed");
4110
4111 do {
4112 if (r1->from() < r2->from()) {
4113 if (r1->to() <= r2->from()) {
4114 r1 = r1->next(); if (r1 == _end) return -1;
4115 } else {
4116 return r2->from();
4117 }
4118 } else if (r2->from() < r1->from()) {
4119 if (r2->to() <= r1->from()) {
4120 r2 = r2->next(); if (r2 == _end) return -1;
4121 } else {
4122 return r1->from();
4123 }
4124 } else { // r1->from() == r2->from()
4125 if (r1->from() == r1->to()) {
4126 r1 = r1->next(); if (r1 == _end) return -1;
4127 } else if (r2->from() == r2->to()) {
4128 r2 = r2->next(); if (r2 == _end) return -1;
4129 } else {
4130 return r1->from();
4131 }
4132 }
4133 } while (true);
4134 }
4135
4136 #ifndef PRODUCT
4137 void Range::print(outputStream* out) const {
4138 out->print("[%d, %d[ ", _from, _to);
4139 }
4140 #endif
4141
4142
4143
4144 // **** Implementation of Interval **********************************
4145
4146 // initialize sentinel
4147 Interval* Interval::_end = nullptr;
4148 void Interval::initialize() {
4149 Range::initialize();
4150 assert(_end == nullptr, "Interval initialized more than once");
4151 alignas(Interval) static uint8_t end_storage[sizeof(Interval)];
4152 _end = ::new(static_cast<void*>(end_storage)) Interval(-1);
4153 }
4154
4155 Interval::Interval(int reg_num) :
4156 _reg_num(reg_num),
4157 _type(T_ILLEGAL),
4158 _first(Range::end()),
4159 _use_pos_and_kinds(12),
4160 _current(Range::end()),
4161 _next(_end),
4162 _state(invalidState),
4163 _assigned_reg(LinearScan::any_reg),
4164 _assigned_regHi(LinearScan::any_reg),
4165 _cached_to(-1),
4166 _cached_opr(LIR_OprFact::illegalOpr),
4167 _cached_vm_reg(VMRegImpl::Bad()),
4168 _split_children(nullptr),
4169 _canonical_spill_slot(-1),
4170 _insert_move_when_activated(false),
4171 _spill_state(noDefinitionFound),
4172 _spill_definition_pos(-1),
4173 _register_hint(nullptr)
4174 {
4175 _split_parent = this;
4176 _current_split_child = this;
4177 }
4178
4179 int Interval::calc_to() {
4180 assert(_first != Range::end(), "interval has no range");
4181
4182 Range* r = _first;
4183 while (r->next() != Range::end()) {
4184 r = r->next();
4185 }
4186 return r->to();
4187 }
4188
4189
4190 #ifdef ASSERT
4191 // consistency check of split-children
4192 void Interval::check_split_children() {
4193 if (_split_children != nullptr && _split_children->length() > 0) {
4194 assert(is_split_parent(), "only split parents can have children");
4195
4196 for (int i = 0; i < _split_children->length(); i++) {
4197 Interval* i1 = _split_children->at(i);
4198
4199 assert(i1->split_parent() == this, "not a split child of this interval");
4200 assert(i1->type() == type(), "must be equal for all split children");
4201 assert(i1->canonical_spill_slot() == canonical_spill_slot(), "must be equal for all split children");
4202
4203 for (int j = i + 1; j < _split_children->length(); j++) {
4204 Interval* i2 = _split_children->at(j);
4205
4206 assert(i1->reg_num() != i2->reg_num(), "same register number");
4207
4208 if (i1->from() < i2->from()) {
4209 assert(i1->to() <= i2->from() && i1->to() < i2->to(), "intervals overlapping");
4210 } else {
4211 assert(i2->from() < i1->from(), "intervals start at same op_id");
4212 assert(i2->to() <= i1->from() && i2->to() < i1->to(), "intervals overlapping");
4213 }
4214 }
4215 }
4216 }
4217 }
4218 #endif // ASSERT
4219
4220 Interval* Interval::register_hint(bool search_split_child) const {
4221 if (!search_split_child) {
4222 return _register_hint;
4223 }
4224
4225 if (_register_hint != nullptr) {
4226 assert(_register_hint->is_split_parent(), "only split parents are valid hint registers");
4227
4228 if (_register_hint->assigned_reg() >= 0 && _register_hint->assigned_reg() < LinearScan::nof_regs) {
4229 return _register_hint;
4230
4231 } else if (_register_hint->_split_children != nullptr && _register_hint->_split_children->length() > 0) {
4232 // search the first split child that has a register assigned
4233 int len = _register_hint->_split_children->length();
4234 for (int i = 0; i < len; i++) {
4235 Interval* cur = _register_hint->_split_children->at(i);
4236
4237 if (cur->assigned_reg() >= 0 && cur->assigned_reg() < LinearScan::nof_regs) {
4238 return cur;
4239 }
4240 }
4241 }
4242 }
4243
4244 // no hint interval found that has a register assigned
4245 return nullptr;
4246 }
4247
4248
4249 Interval* Interval::split_child_at_op_id(int op_id, LIR_OpVisitState::OprMode mode) {
4250 assert(is_split_parent(), "can only be called for split parents");
4251 assert(op_id >= 0, "invalid op_id (method can not be called for spill moves)");
4252
4253 Interval* result;
4254 if (_split_children == nullptr || _split_children->length() == 0) {
4255 result = this;
4256 } else {
4257 result = nullptr;
4258 int len = _split_children->length();
4259
4260 // in outputMode, the end of the interval (op_id == cur->to()) is not valid
4261 int to_offset = (mode == LIR_OpVisitState::outputMode ? 0 : 1);
4262
4263 int i;
4264 for (i = 0; i < len; i++) {
4265 Interval* cur = _split_children->at(i);
4266 if (cur->from() <= op_id && op_id < cur->to() + to_offset) {
4267 if (i > 0) {
4268 // exchange current split child to start of list (faster access for next call)
4269 _split_children->at_put(i, _split_children->at(0));
4270 _split_children->at_put(0, cur);
4271 }
4272
4273 // interval found
4274 result = cur;
4275 break;
4276 }
4277 }
4278
4279 #ifdef ASSERT
4280 for (i = 0; i < len; i++) {
4281 Interval* tmp = _split_children->at(i);
4282 if (tmp != result && tmp->from() <= op_id && op_id < tmp->to() + to_offset) {
4283 tty->print_cr("two valid result intervals found for op_id %d: %d and %d", op_id, result->reg_num(), tmp->reg_num());
4284 result->print();
4285 tmp->print();
4286 assert(false, "two valid result intervals found");
4287 }
4288 }
4289 #endif
4290 }
4291
4292 assert(result != nullptr, "no matching interval found");
4293 assert(result->covers(op_id, mode), "op_id not covered by interval");
4294
4295 return result;
4296 }
4297
4298
4299 // returns the last split child that ends before the given op_id
4300 Interval* Interval::split_child_before_op_id(int op_id) {
4301 assert(op_id >= 0, "invalid op_id");
4302
4303 Interval* parent = split_parent();
4304 Interval* result = nullptr;
4305
4306 assert(parent->_split_children != nullptr, "no split children available");
4307 int len = parent->_split_children->length();
4308 assert(len > 0, "no split children available");
4309
4310 for (int i = len - 1; i >= 0; i--) {
4311 Interval* cur = parent->_split_children->at(i);
4312 if (cur->to() <= op_id && (result == nullptr || result->to() < cur->to())) {
4313 result = cur;
4314 }
4315 }
4316
4317 assert(result != nullptr, "no split child found");
4318 return result;
4319 }
4320
4321
4322 // Note: use positions are sorted descending -> first use has highest index
4323 int Interval::first_usage(IntervalUseKind min_use_kind) const {
4324 assert(LinearScan::is_virtual_interval(this), "cannot access use positions for fixed intervals");
4325
4326 for (int i = _use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
4327 if (_use_pos_and_kinds.at(i + 1) >= min_use_kind) {
4328 return _use_pos_and_kinds.at(i);
4329 }
4330 }
4331 return max_jint;
4332 }
4333
4334 int Interval::next_usage(IntervalUseKind min_use_kind, int from) const {
4335 assert(LinearScan::is_virtual_interval(this), "cannot access use positions for fixed intervals");
4336
4337 for (int i = _use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
4338 if (_use_pos_and_kinds.at(i) >= from && _use_pos_and_kinds.at(i + 1) >= min_use_kind) {
4339 return _use_pos_and_kinds.at(i);
4340 }
4341 }
4342 return max_jint;
4343 }
4344
4345 int Interval::next_usage_exact(IntervalUseKind exact_use_kind, int from) const {
4346 assert(LinearScan::is_virtual_interval(this), "cannot access use positions for fixed intervals");
4347
4348 for (int i = _use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
4349 if (_use_pos_and_kinds.at(i) >= from && _use_pos_and_kinds.at(i + 1) == exact_use_kind) {
4350 return _use_pos_and_kinds.at(i);
4351 }
4352 }
4353 return max_jint;
4354 }
4355
4356 int Interval::previous_usage(IntervalUseKind min_use_kind, int from) const {
4357 assert(LinearScan::is_virtual_interval(this), "cannot access use positions for fixed intervals");
4358
4359 int prev = 0;
4360 for (int i = _use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
4361 if (_use_pos_and_kinds.at(i) > from) {
4362 return prev;
4363 }
4364 if (_use_pos_and_kinds.at(i + 1) >= min_use_kind) {
4365 prev = _use_pos_and_kinds.at(i);
4366 }
4367 }
4368 return prev;
4369 }
4370
4371 void Interval::add_use_pos(int pos, IntervalUseKind use_kind) {
4372 assert(covers(pos, LIR_OpVisitState::inputMode), "use position not covered by live range");
4373
4374 // do not add use positions for precolored intervals because
4375 // they are never used
4376 if (use_kind != noUse && reg_num() >= LIR_Opr::vreg_base) {
4377 #ifdef ASSERT
4378 assert(_use_pos_and_kinds.length() % 2 == 0, "must be");
4379 for (int i = 0; i < _use_pos_and_kinds.length(); i += 2) {
4380 assert(pos <= _use_pos_and_kinds.at(i), "already added a use-position with lower position");
4381 assert(_use_pos_and_kinds.at(i + 1) >= firstValidKind && _use_pos_and_kinds.at(i + 1) <= lastValidKind, "invalid use kind");
4382 if (i > 0) {
4383 assert(_use_pos_and_kinds.at(i) < _use_pos_and_kinds.at(i - 2), "not sorted descending");
4384 }
4385 }
4386 #endif
4387
4388 // Note: add_use is called in descending order, so list gets sorted
4389 // automatically by just appending new use positions
4390 int len = _use_pos_and_kinds.length();
4391 if (len == 0 || _use_pos_and_kinds.at(len - 2) > pos) {
4392 _use_pos_and_kinds.append(pos);
4393 _use_pos_and_kinds.append(use_kind);
4394 } else if (_use_pos_and_kinds.at(len - 1) < use_kind) {
4395 assert(_use_pos_and_kinds.at(len - 2) == pos, "list not sorted correctly");
4396 _use_pos_and_kinds.at_put(len - 1, use_kind);
4397 }
4398 }
4399 }
4400
4401 void Interval::add_range(int from, int to) {
4402 assert(from < to, "invalid range");
4403 assert(first() == Range::end() || to < first()->next()->from(), "not inserting at begin of interval");
4404 assert(from <= first()->to(), "not inserting at begin of interval");
4405
4406 if (first()->from() <= to) {
4407 // join intersecting ranges
4408 first()->set_from(MIN2(from, first()->from()));
4409 first()->set_to (MAX2(to, first()->to()));
4410 } else {
4411 // insert new range
4412 _first = new Range(from, to, first());
4413 }
4414 }
4415
4416 Interval* Interval::new_split_child() {
4417 // allocate new interval
4418 Interval* result = new Interval(-1);
4419 result->set_type(type());
4420
4421 Interval* parent = split_parent();
4422 result->_split_parent = parent;
4423 result->set_register_hint(parent);
4424
4425 // insert new interval in children-list of parent
4426 if (parent->_split_children == nullptr) {
4427 assert(is_split_parent(), "list must be initialized at first split");
4428
4429 parent->_split_children = new IntervalList(4);
4430 parent->_split_children->append(this);
4431 }
4432 parent->_split_children->append(result);
4433
4434 return result;
4435 }
4436
4437 // split this interval at the specified position and return
4438 // the remainder as a new interval.
4439 //
4440 // when an interval is split, a bi-directional link is established between the original interval
4441 // (the split parent) and the intervals that are split off this interval (the split children)
4442 // When a split child is split again, the new created interval is also a direct child
4443 // of the original parent (there is no tree of split children stored, but a flat list)
4444 // All split children are spilled to the same stack slot (stored in _canonical_spill_slot)
4445 //
4446 // Note: The new interval has no valid reg_num
4447 Interval* Interval::split(int split_pos) {
4448 assert(LinearScan::is_virtual_interval(this), "cannot split fixed intervals");
4449
4450 // allocate new interval
4451 Interval* result = new_split_child();
4452
4453 // split the ranges
4454 Range* prev = nullptr;
4455 Range* cur = _first;
4456 while (cur != Range::end() && cur->to() <= split_pos) {
4457 prev = cur;
4458 cur = cur->next();
4459 }
4460 assert(cur != Range::end(), "split interval after end of last range");
4461
4462 if (cur->from() < split_pos) {
4463 result->_first = new Range(split_pos, cur->to(), cur->next());
4464 cur->set_to(split_pos);
4465 cur->set_next(Range::end());
4466
4467 } else {
4468 assert(prev != nullptr, "split before start of first range");
4469 result->_first = cur;
4470 prev->set_next(Range::end());
4471 }
4472 result->_current = result->_first;
4473 _cached_to = -1; // clear cached value
4474
4475 // split list of use positions
4476 int total_len = _use_pos_and_kinds.length();
4477 int start_idx = total_len - 2;
4478 while (start_idx >= 0 && _use_pos_and_kinds.at(start_idx) < split_pos) {
4479 start_idx -= 2;
4480 }
4481
4482 intStack new_use_pos_and_kinds(total_len - start_idx);
4483 int i;
4484 for (i = start_idx + 2; i < total_len; i++) {
4485 new_use_pos_and_kinds.append(_use_pos_and_kinds.at(i));
4486 }
4487
4488 _use_pos_and_kinds.trunc_to(start_idx + 2);
4489 result->_use_pos_and_kinds = _use_pos_and_kinds;
4490 _use_pos_and_kinds = new_use_pos_and_kinds;
4491
4492 #ifdef ASSERT
4493 assert(_use_pos_and_kinds.length() % 2 == 0, "must have use kind for each use pos");
4494 assert(result->_use_pos_and_kinds.length() % 2 == 0, "must have use kind for each use pos");
4495 assert(_use_pos_and_kinds.length() + result->_use_pos_and_kinds.length() == total_len, "missed some entries");
4496
4497 for (i = 0; i < _use_pos_and_kinds.length(); i += 2) {
4498 assert(_use_pos_and_kinds.at(i) < split_pos, "must be");
4499 assert(_use_pos_and_kinds.at(i + 1) >= firstValidKind && _use_pos_and_kinds.at(i + 1) <= lastValidKind, "invalid use kind");
4500 }
4501 for (i = 0; i < result->_use_pos_and_kinds.length(); i += 2) {
4502 assert(result->_use_pos_and_kinds.at(i) >= split_pos, "must be");
4503 assert(result->_use_pos_and_kinds.at(i + 1) >= firstValidKind && result->_use_pos_and_kinds.at(i + 1) <= lastValidKind, "invalid use kind");
4504 }
4505 #endif
4506
4507 return result;
4508 }
4509
4510 // split this interval at the specified position and return
4511 // the head as a new interval (the original interval is the tail)
4512 //
4513 // Currently, only the first range can be split, and the new interval
4514 // must not have split positions
4515 Interval* Interval::split_from_start(int split_pos) {
4516 assert(LinearScan::is_virtual_interval(this), "cannot split fixed intervals");
4517 assert(split_pos > from() && split_pos < to(), "can only split inside interval");
4518 assert(split_pos > _first->from() && split_pos <= _first->to(), "can only split inside first range");
4519 assert(first_usage(noUse) > split_pos, "can not split when use positions are present");
4520
4521 // allocate new interval
4522 Interval* result = new_split_child();
4523
4524 // the new created interval has only one range (checked by assertion above),
4525 // so the splitting of the ranges is very simple
4526 result->add_range(_first->from(), split_pos);
4527
4528 if (split_pos == _first->to()) {
4529 assert(_first->next() != Range::end(), "must not be at end");
4530 _first = _first->next();
4531 } else {
4532 _first->set_from(split_pos);
4533 }
4534
4535 return result;
4536 }
4537
4538
4539 // returns true if the op_id is inside the interval
4540 bool Interval::covers(int op_id, LIR_OpVisitState::OprMode mode) const {
4541 Range* cur = _first;
4542
4543 while (cur != Range::end() && cur->to() < op_id) {
4544 cur = cur->next();
4545 }
4546 if (cur != Range::end()) {
4547 assert(cur->to() != cur->next()->from(), "ranges not separated");
4548
4549 if (mode == LIR_OpVisitState::outputMode) {
4550 return cur->from() <= op_id && op_id < cur->to();
4551 } else {
4552 return cur->from() <= op_id && op_id <= cur->to();
4553 }
4554 }
4555 return false;
4556 }
4557
4558 // returns true if the interval has any hole between hole_from and hole_to
4559 // (even if the hole has only the length 1)
4560 bool Interval::has_hole_between(int hole_from, int hole_to) {
4561 assert(hole_from < hole_to, "check");
4562 assert(from() <= hole_from && hole_to <= to(), "index out of interval");
4563
4564 Range* cur = _first;
4565 while (cur != Range::end()) {
4566 assert(cur->to() < cur->next()->from(), "no space between ranges");
4567
4568 // hole-range starts before this range -> hole
4569 if (hole_from < cur->from()) {
4570 return true;
4571
4572 // hole-range completely inside this range -> no hole
4573 } else if (hole_to <= cur->to()) {
4574 return false;
4575
4576 // overlapping of hole-range with this range -> hole
4577 } else if (hole_from <= cur->to()) {
4578 return true;
4579 }
4580
4581 cur = cur->next();
4582 }
4583
4584 return false;
4585 }
4586
4587 // Check if there is an intersection with any of the split children of 'interval'
4588 bool Interval::intersects_any_children_of(Interval* interval) const {
4589 if (interval->_split_children != nullptr) {
4590 for (int i = 0; i < interval->_split_children->length(); i++) {
4591 if (intersects(interval->_split_children->at(i))) {
4592 return true;
4593 }
4594 }
4595 }
4596 return false;
4597 }
4598
4599
4600 #ifndef PRODUCT
4601 void Interval::print_on(outputStream* out, bool is_cfg_printer) const {
4602 const char* SpillState2Name[] = { "no definition", "no spill store", "one spill store", "store at definition", "start in memory", "no optimization" };
4603 const char* UseKind2Name[] = { "N", "L", "S", "M" };
4604
4605 const char* type_name;
4606 if (reg_num() < LIR_Opr::vreg_base) {
4607 type_name = "fixed";
4608 } else {
4609 type_name = type2name(type());
4610 }
4611 out->print("%d %s ", reg_num(), type_name);
4612
4613 if (is_cfg_printer) {
4614 // Special version for compatibility with C1 Visualizer.
4615 LIR_Opr opr = LinearScan::get_operand(reg_num());
4616 if (opr->is_valid()) {
4617 out->print("\"");
4618 opr->print(out);
4619 out->print("\" ");
4620 }
4621 } else {
4622 // Improved output for normal debugging.
4623 if (reg_num() < LIR_Opr::vreg_base) {
4624 LinearScan::print_reg_num(out, assigned_reg());
4625 } else if (assigned_reg() != -1 && (LinearScan::num_physical_regs(type()) == 1 || assigned_regHi() != -1)) {
4626 LinearScan::calc_operand_for_interval(this)->print(out);
4627 } else {
4628 // Virtual register that has no assigned register yet.
4629 out->print("[ANY]");
4630 }
4631 out->print(" ");
4632 }
4633 out->print("%d %d ", split_parent()->reg_num(), (register_hint(false) != nullptr ? register_hint(false)->reg_num() : -1));
4634
4635 // print ranges
4636 Range* cur = _first;
4637 while (cur != Range::end()) {
4638 cur->print(out);
4639 cur = cur->next();
4640 assert(cur != nullptr, "range list not closed with range sentinel");
4641 }
4642
4643 // print use positions
4644 int prev = 0;
4645 assert(_use_pos_and_kinds.length() % 2 == 0, "must be");
4646 for (int i =_use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
4647 assert(_use_pos_and_kinds.at(i + 1) >= firstValidKind && _use_pos_and_kinds.at(i + 1) <= lastValidKind, "invalid use kind");
4648 assert(prev < _use_pos_and_kinds.at(i), "use positions not sorted");
4649
4650 out->print("%d %s ", _use_pos_and_kinds.at(i), UseKind2Name[_use_pos_and_kinds.at(i + 1)]);
4651 prev = _use_pos_and_kinds.at(i);
4652 }
4653
4654 out->print(" \"%s\"", SpillState2Name[spill_state()]);
4655 out->cr();
4656 }
4657
4658 void Interval::print_parent() const {
4659 if (_split_parent != this) {
4660 _split_parent->print_on(tty);
4661 } else {
4662 tty->print_cr("Parent: this");
4663 }
4664 }
4665
4666 void Interval::print_children() const {
4667 if (_split_children == nullptr) {
4668 tty->print_cr("Children: []");
4669 } else {
4670 tty->print_cr("Children:");
4671 for (int i = 0; i < _split_children->length(); i++) {
4672 tty->print("%d: ", i);
4673 _split_children->at(i)->print_on(tty);
4674 }
4675 }
4676 }
4677 #endif // NOT PRODUCT
4678
4679
4680
4681
4682 // **** Implementation of IntervalWalker ****************************
4683
4684 IntervalWalker::IntervalWalker(LinearScan* allocator, Interval* unhandled_fixed_first, Interval* unhandled_any_first)
4685 : _compilation(allocator->compilation())
4686 , _allocator(allocator)
4687 {
4688 _unhandled_first[fixedKind] = unhandled_fixed_first;
4689 _unhandled_first[anyKind] = unhandled_any_first;
4690 _active_first[fixedKind] = Interval::end();
4691 _inactive_first[fixedKind] = Interval::end();
4692 _active_first[anyKind] = Interval::end();
4693 _inactive_first[anyKind] = Interval::end();
4694 _current_position = -1;
4695 _current = nullptr;
4696 next_interval();
4697 }
4698
4699
4700 // append interval in order of current range from()
4701 void IntervalWalker::append_sorted(Interval** list, Interval* interval) {
4702 Interval* prev = nullptr;
4703 Interval* cur = *list;
4704 while (cur->current_from() < interval->current_from()) {
4705 prev = cur; cur = cur->next();
4706 }
4707 if (prev == nullptr) {
4708 *list = interval;
4709 } else {
4710 prev->set_next(interval);
4711 }
4712 interval->set_next(cur);
4713 }
4714
4715 void IntervalWalker::append_to_unhandled(Interval** list, Interval* interval) {
4716 assert(interval->from() >= current()->current_from(), "cannot append new interval before current walk position");
4717
4718 Interval* prev = nullptr;
4719 Interval* cur = *list;
4720 while (cur->from() < interval->from() || (cur->from() == interval->from() && cur->first_usage(noUse) < interval->first_usage(noUse))) {
4721 prev = cur; cur = cur->next();
4722 }
4723 if (prev == nullptr) {
4724 *list = interval;
4725 } else {
4726 prev->set_next(interval);
4727 }
4728 interval->set_next(cur);
4729 }
4730
4731
4732 inline bool IntervalWalker::remove_from_list(Interval** list, Interval* i) {
4733 while (*list != Interval::end() && *list != i) {
4734 list = (*list)->next_addr();
4735 }
4736 if (*list != Interval::end()) {
4737 assert(*list == i, "check");
4738 *list = (*list)->next();
4739 return true;
4740 } else {
4741 return false;
4742 }
4743 }
4744
4745 void IntervalWalker::remove_from_list(Interval* i) {
4746 bool deleted;
4747
4748 if (i->state() == activeState) {
4749 deleted = remove_from_list(active_first_addr(anyKind), i);
4750 } else {
4751 assert(i->state() == inactiveState, "invalid state");
4752 deleted = remove_from_list(inactive_first_addr(anyKind), i);
4753 }
4754
4755 assert(deleted, "interval has not been found in list");
4756 }
4757
4758
4759 void IntervalWalker::walk_to(IntervalState state, int from) {
4760 assert (state == activeState || state == inactiveState, "wrong state");
4761 for_each_interval_kind(kind) {
4762 Interval** prev = state == activeState ? active_first_addr(kind) : inactive_first_addr(kind);
4763 Interval* next = *prev;
4764 while (next->current_from() <= from) {
4765 Interval* cur = next;
4766 next = cur->next();
4767
4768 bool range_has_changed = false;
4769 while (cur->current_to() <= from) {
4770 cur->next_range();
4771 range_has_changed = true;
4772 }
4773
4774 // also handle move from inactive list to active list
4775 range_has_changed = range_has_changed || (state == inactiveState && cur->current_from() <= from);
4776
4777 if (range_has_changed) {
4778 // remove cur from list
4779 *prev = next;
4780 if (cur->current_at_end()) {
4781 // move to handled state (not maintained as a list)
4782 cur->set_state(handledState);
4783 DEBUG_ONLY(interval_moved(cur, kind, state, handledState);)
4784 } else if (cur->current_from() <= from){
4785 // sort into active list
4786 append_sorted(active_first_addr(kind), cur);
4787 cur->set_state(activeState);
4788 if (*prev == cur) {
4789 assert(state == activeState, "check");
4790 prev = cur->next_addr();
4791 }
4792 DEBUG_ONLY(interval_moved(cur, kind, state, activeState);)
4793 } else {
4794 // sort into inactive list
4795 append_sorted(inactive_first_addr(kind), cur);
4796 cur->set_state(inactiveState);
4797 if (*prev == cur) {
4798 assert(state == inactiveState, "check");
4799 prev = cur->next_addr();
4800 }
4801 DEBUG_ONLY(interval_moved(cur, kind, state, inactiveState);)
4802 }
4803 } else {
4804 prev = cur->next_addr();
4805 continue;
4806 }
4807 }
4808 }
4809 }
4810
4811
4812 void IntervalWalker::next_interval() {
4813 IntervalKind kind;
4814 Interval* any = _unhandled_first[anyKind];
4815 Interval* fixed = _unhandled_first[fixedKind];
4816
4817 if (any != Interval::end()) {
4818 // intervals may start at same position -> prefer fixed interval
4819 kind = fixed != Interval::end() && fixed->from() <= any->from() ? fixedKind : anyKind;
4820
4821 assert((kind == fixedKind && fixed->from() <= any->from()) ||
4822 (kind == anyKind && any->from() <= fixed->from()), "wrong interval!!!");
4823 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");
4824
4825 } else if (fixed != Interval::end()) {
4826 kind = fixedKind;
4827 } else {
4828 _current = nullptr; return;
4829 }
4830 _current_kind = kind;
4831 _current = _unhandled_first[kind];
4832 _unhandled_first[kind] = _current->next();
4833 _current->set_next(Interval::end());
4834 _current->rewind_range();
4835 }
4836
4837
4838 void IntervalWalker::walk_to(int lir_op_id) {
4839 assert(_current_position <= lir_op_id, "can not walk backwards");
4840 while (current() != nullptr) {
4841 bool is_active = current()->from() <= lir_op_id;
4842 int id = is_active ? current()->from() : lir_op_id;
4843
4844 TRACE_LINEAR_SCAN(2, if (_current_position < id) { tty->cr(); tty->print_cr("walk_to(%d) **************************************************************", id); })
4845
4846 // set _current_position prior to call of walk_to
4847 _current_position = id;
4848
4849 // call walk_to even if _current_position == id
4850 walk_to(activeState, id);
4851 walk_to(inactiveState, id);
4852
4853 if (is_active) {
4854 current()->set_state(activeState);
4855 if (activate_current()) {
4856 append_sorted(active_first_addr(current_kind()), current());
4857 DEBUG_ONLY(interval_moved(current(), current_kind(), unhandledState, activeState);)
4858 }
4859
4860 next_interval();
4861 } else {
4862 return;
4863 }
4864 }
4865 }
4866
4867 #ifdef ASSERT
4868 void IntervalWalker::interval_moved(Interval* interval, IntervalKind kind, IntervalState from, IntervalState to) {
4869 if (TraceLinearScanLevel >= 4) {
4870 #define print_state(state) \
4871 switch(state) {\
4872 case unhandledState: tty->print("unhandled"); break;\
4873 case activeState: tty->print("active"); break;\
4874 case inactiveState: tty->print("inactive"); break;\
4875 case handledState: tty->print("handled"); break;\
4876 default: ShouldNotReachHere(); \
4877 }
4878
4879 print_state(from); tty->print(" to "); print_state(to);
4880 tty->fill_to(23);
4881 interval->print();
4882
4883 #undef print_state
4884 }
4885 }
4886 #endif // ASSERT
4887
4888 // **** Implementation of LinearScanWalker **************************
4889
4890 LinearScanWalker::LinearScanWalker(LinearScan* allocator, Interval* unhandled_fixed_first, Interval* unhandled_any_first)
4891 : IntervalWalker(allocator, unhandled_fixed_first, unhandled_any_first)
4892 , _move_resolver(allocator)
4893 {
4894 for (int i = 0; i < LinearScan::nof_regs; i++) {
4895 _spill_intervals[i] = new IntervalList(2);
4896 }
4897 }
4898
4899
4900 inline void LinearScanWalker::init_use_lists(bool only_process_use_pos) {
4901 for (int i = _first_reg; i <= _last_reg; i++) {
4902 _use_pos[i] = max_jint;
4903
4904 if (!only_process_use_pos) {
4905 _block_pos[i] = max_jint;
4906 _spill_intervals[i]->clear();
4907 }
4908 }
4909 }
4910
4911 inline void LinearScanWalker::exclude_from_use(int reg) {
4912 assert(reg < LinearScan::nof_regs, "interval must have a register assigned (stack slots not allowed)");
4913 if (reg >= _first_reg && reg <= _last_reg) {
4914 _use_pos[reg] = 0;
4915 }
4916 }
4917 inline void LinearScanWalker::exclude_from_use(Interval* i) {
4918 assert(i->assigned_reg() != any_reg, "interval has no register assigned");
4919
4920 exclude_from_use(i->assigned_reg());
4921 exclude_from_use(i->assigned_regHi());
4922 }
4923
4924 inline void LinearScanWalker::set_use_pos(int reg, Interval* i, int use_pos, bool only_process_use_pos) {
4925 assert(use_pos != 0, "must use exclude_from_use to set use_pos to 0");
4926
4927 if (reg >= _first_reg && reg <= _last_reg) {
4928 if (_use_pos[reg] > use_pos) {
4929 _use_pos[reg] = use_pos;
4930 }
4931 if (!only_process_use_pos) {
4932 _spill_intervals[reg]->append(i);
4933 }
4934 }
4935 }
4936 inline void LinearScanWalker::set_use_pos(Interval* i, int use_pos, bool only_process_use_pos) {
4937 assert(i->assigned_reg() != any_reg, "interval has no register assigned");
4938 if (use_pos != -1) {
4939 set_use_pos(i->assigned_reg(), i, use_pos, only_process_use_pos);
4940 set_use_pos(i->assigned_regHi(), i, use_pos, only_process_use_pos);
4941 }
4942 }
4943
4944 inline void LinearScanWalker::set_block_pos(int reg, Interval* i, int block_pos) {
4945 if (reg >= _first_reg && reg <= _last_reg) {
4946 if (_block_pos[reg] > block_pos) {
4947 _block_pos[reg] = block_pos;
4948 }
4949 if (_use_pos[reg] > block_pos) {
4950 _use_pos[reg] = block_pos;
4951 }
4952 }
4953 }
4954 inline void LinearScanWalker::set_block_pos(Interval* i, int block_pos) {
4955 assert(i->assigned_reg() != any_reg, "interval has no register assigned");
4956 if (block_pos != -1) {
4957 set_block_pos(i->assigned_reg(), i, block_pos);
4958 set_block_pos(i->assigned_regHi(), i, block_pos);
4959 }
4960 }
4961
4962
4963 void LinearScanWalker::free_exclude_active_fixed() {
4964 Interval* list = active_first(fixedKind);
4965 while (list != Interval::end()) {
4966 assert(list->assigned_reg() < LinearScan::nof_regs, "active interval must have a register assigned");
4967 exclude_from_use(list);
4968 list = list->next();
4969 }
4970 }
4971
4972 void LinearScanWalker::free_exclude_active_any() {
4973 Interval* list = active_first(anyKind);
4974 while (list != Interval::end()) {
4975 exclude_from_use(list);
4976 list = list->next();
4977 }
4978 }
4979
4980 void LinearScanWalker::free_collect_inactive_fixed(Interval* cur) {
4981 Interval* list = inactive_first(fixedKind);
4982 while (list != Interval::end()) {
4983 if (cur->to() <= list->current_from()) {
4984 assert(list->current_intersects_at(cur) == -1, "must not intersect");
4985 set_use_pos(list, list->current_from(), true);
4986 } else {
4987 set_use_pos(list, list->current_intersects_at(cur), true);
4988 }
4989 list = list->next();
4990 }
4991 }
4992
4993 void LinearScanWalker::free_collect_inactive_any(Interval* cur) {
4994 Interval* list = inactive_first(anyKind);
4995 while (list != Interval::end()) {
4996 set_use_pos(list, list->current_intersects_at(cur), true);
4997 list = list->next();
4998 }
4999 }
5000
5001 void LinearScanWalker::spill_exclude_active_fixed() {
5002 Interval* list = active_first(fixedKind);
5003 while (list != Interval::end()) {
5004 exclude_from_use(list);
5005 list = list->next();
5006 }
5007 }
5008
5009 void LinearScanWalker::spill_block_inactive_fixed(Interval* cur) {
5010 Interval* list = inactive_first(fixedKind);
5011 while (list != Interval::end()) {
5012 if (cur->to() > list->current_from()) {
5013 set_block_pos(list, list->current_intersects_at(cur));
5014 } else {
5015 assert(list->current_intersects_at(cur) == -1, "invalid optimization: intervals intersect");
5016 }
5017
5018 list = list->next();
5019 }
5020 }
5021
5022 void LinearScanWalker::spill_collect_active_any() {
5023 Interval* list = active_first(anyKind);
5024 while (list != Interval::end()) {
5025 set_use_pos(list, MIN2(list->next_usage(loopEndMarker, _current_position), list->to()), false);
5026 list = list->next();
5027 }
5028 }
5029
5030 void LinearScanWalker::spill_collect_inactive_any(Interval* cur) {
5031 Interval* list = inactive_first(anyKind);
5032 while (list != Interval::end()) {
5033 if (list->current_intersects(cur)) {
5034 set_use_pos(list, MIN2(list->next_usage(loopEndMarker, _current_position), list->to()), false);
5035 }
5036 list = list->next();
5037 }
5038 }
5039
5040
5041 void LinearScanWalker::insert_move(int op_id, Interval* src_it, Interval* dst_it) {
5042 // output all moves here. When source and target are equal, the move is
5043 // optimized away later in assign_reg_nums
5044
5045 op_id = (op_id + 1) & ~1;
5046 BlockBegin* op_block = allocator()->block_of_op_with_id(op_id);
5047 assert(op_id > 0 && allocator()->block_of_op_with_id(op_id - 2) == op_block, "cannot insert move at block boundary");
5048
5049 // calculate index of instruction inside instruction list of current block
5050 // the minimal index (for a block with no spill moves) can be calculated because the
5051 // numbering of instructions is known.
5052 // When the block already contains spill moves, the index must be increased until the
5053 // correct index is reached.
5054 LIR_OpList* list = op_block->lir()->instructions_list();
5055 int index = (op_id - list->at(0)->id()) / 2;
5056 assert(list->at(index)->id() <= op_id, "error in calculation");
5057
5058 while (list->at(index)->id() != op_id) {
5059 index++;
5060 assert(0 <= index && index < list->length(), "index out of bounds");
5061 }
5062 assert(1 <= index && index < list->length(), "index out of bounds");
5063 assert(list->at(index)->id() == op_id, "error in calculation");
5064
5065 // insert new instruction before instruction at position index
5066 _move_resolver.move_insert_position(op_block->lir(), index - 1);
5067 _move_resolver.add_mapping(src_it, dst_it);
5068 }
5069
5070
5071 int LinearScanWalker::find_optimal_split_pos(BlockBegin* min_block, BlockBegin* max_block, int max_split_pos) {
5072 int from_block_nr = min_block->linear_scan_number();
5073 int to_block_nr = max_block->linear_scan_number();
5074
5075 assert(0 <= from_block_nr && from_block_nr < block_count(), "out of range");
5076 assert(0 <= to_block_nr && to_block_nr < block_count(), "out of range");
5077 assert(from_block_nr < to_block_nr, "must cross block boundary");
5078
5079 // Try to split at end of max_block. If this would be after
5080 // max_split_pos, then use the begin of max_block
5081 int optimal_split_pos = max_block->last_lir_instruction_id() + 2;
5082 if (optimal_split_pos > max_split_pos) {
5083 optimal_split_pos = max_block->first_lir_instruction_id();
5084 }
5085
5086 int min_loop_depth = max_block->loop_depth();
5087 for (int i = to_block_nr - 1; i >= from_block_nr; i--) {
5088 BlockBegin* cur = block_at(i);
5089
5090 if (cur->loop_depth() < min_loop_depth) {
5091 // block with lower loop-depth found -> split at the end of this block
5092 min_loop_depth = cur->loop_depth();
5093 optimal_split_pos = cur->last_lir_instruction_id() + 2;
5094 }
5095 }
5096 assert(optimal_split_pos > allocator()->max_lir_op_id() || allocator()->is_block_begin(optimal_split_pos), "algorithm must move split pos to block boundary");
5097
5098 return optimal_split_pos;
5099 }
5100
5101
5102 int LinearScanWalker::find_optimal_split_pos(Interval* it, int min_split_pos, int max_split_pos, bool do_loop_optimization) {
5103 int optimal_split_pos = -1;
5104 if (min_split_pos == max_split_pos) {
5105 // trivial case, no optimization of split position possible
5106 TRACE_LINEAR_SCAN(4, tty->print_cr(" min-pos and max-pos are equal, no optimization possible"));
5107 optimal_split_pos = min_split_pos;
5108
5109 } else {
5110 assert(min_split_pos < max_split_pos, "must be true then");
5111 assert(min_split_pos > 0, "cannot access min_split_pos - 1 otherwise");
5112
5113 // reason for using min_split_pos - 1: when the minimal split pos is exactly at the
5114 // beginning of a block, then min_split_pos is also a possible split position.
5115 // Use the block before as min_block, because then min_block->last_lir_instruction_id() + 2 == min_split_pos
5116 BlockBegin* min_block = allocator()->block_of_op_with_id(min_split_pos - 1);
5117
5118 // reason for using max_split_pos - 1: otherwise there would be an assertion failure
5119 // when an interval ends at the end of the last block of the method
5120 // (in this case, max_split_pos == allocator()->max_lir_op_id() + 2, and there is no
5121 // block at this op_id)
5122 BlockBegin* max_block = allocator()->block_of_op_with_id(max_split_pos - 1);
5123
5124 assert(min_block->linear_scan_number() <= max_block->linear_scan_number(), "invalid order");
5125 if (min_block == max_block) {
5126 // split position cannot be moved to block boundary, so split as late as possible
5127 TRACE_LINEAR_SCAN(4, tty->print_cr(" cannot move split pos to block boundary because min_pos and max_pos are in same block"));
5128 optimal_split_pos = max_split_pos;
5129
5130 } else if (it->has_hole_between(max_split_pos - 1, max_split_pos) && !allocator()->is_block_begin(max_split_pos)) {
5131 // Do not move split position if the interval has a hole before max_split_pos.
5132 // Intervals resulting from Phi-Functions have more than one definition (marked
5133 // as mustHaveRegister) with a hole before each definition. When the register is needed
5134 // for the second definition, an earlier reloading is unnecessary.
5135 TRACE_LINEAR_SCAN(4, tty->print_cr(" interval has hole just before max_split_pos, so splitting at max_split_pos"));
5136 optimal_split_pos = max_split_pos;
5137
5138 } else {
5139 // search optimal block boundary between min_split_pos and max_split_pos
5140 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()));
5141
5142 if (do_loop_optimization) {
5143 // Loop optimization: if a loop-end marker is found between min- and max-position,
5144 // then split before this loop
5145 int loop_end_pos = it->next_usage_exact(loopEndMarker, min_block->last_lir_instruction_id() + 2);
5146 TRACE_LINEAR_SCAN(4, tty->print_cr(" loop optimization: loop end found at pos %d", loop_end_pos));
5147
5148 assert(loop_end_pos > min_split_pos, "invalid order");
5149 if (loop_end_pos < max_split_pos) {
5150 // loop-end marker found between min- and max-position
5151 // if it is not the end marker for the same loop as the min-position, then move
5152 // the max-position to this loop block.
5153 // Desired result: uses tagged as shouldHaveRegister inside a loop cause a reloading
5154 // of the interval (normally, only mustHaveRegister causes a reloading)
5155 BlockBegin* loop_block = allocator()->block_of_op_with_id(loop_end_pos);
5156
5157 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()));
5158 assert(loop_block != min_block, "loop_block and min_block must be different because block boundary is needed between");
5159
5160 optimal_split_pos = find_optimal_split_pos(min_block, loop_block, loop_block->last_lir_instruction_id() + 2);
5161 if (optimal_split_pos == loop_block->last_lir_instruction_id() + 2) {
5162 optimal_split_pos = -1;
5163 TRACE_LINEAR_SCAN(4, tty->print_cr(" loop optimization not necessary"));
5164 } else {
5165 TRACE_LINEAR_SCAN(4, tty->print_cr(" loop optimization successful"));
5166 }
5167 }
5168 }
5169
5170 if (optimal_split_pos == -1) {
5171 // not calculated by loop optimization
5172 optimal_split_pos = find_optimal_split_pos(min_block, max_block, max_split_pos);
5173 }
5174 }
5175 }
5176 TRACE_LINEAR_SCAN(4, tty->print_cr(" optimal split position: %d", optimal_split_pos));
5177
5178 return optimal_split_pos;
5179 }
5180
5181
5182 /*
5183 split an interval at the optimal position between min_split_pos and
5184 max_split_pos in two parts:
5185 1) the left part has already a location assigned
5186 2) the right part is sorted into to the unhandled-list
5187 */
5188 void LinearScanWalker::split_before_usage(Interval* it, int min_split_pos, int max_split_pos) {
5189 TRACE_LINEAR_SCAN(2, tty->print ("----- splitting interval: "); it->print());
5190 TRACE_LINEAR_SCAN(2, tty->print_cr(" between %d and %d", min_split_pos, max_split_pos));
5191
5192 assert(it->from() < min_split_pos, "cannot split at start of interval");
5193 assert(current_position() < min_split_pos, "cannot split before current position");
5194 assert(min_split_pos <= max_split_pos, "invalid order");
5195 assert(max_split_pos <= it->to(), "cannot split after end of interval");
5196
5197 int optimal_split_pos = find_optimal_split_pos(it, min_split_pos, max_split_pos, true);
5198
5199 assert(min_split_pos <= optimal_split_pos && optimal_split_pos <= max_split_pos, "out of range");
5200 assert(optimal_split_pos <= it->to(), "cannot split after end of interval");
5201 assert(optimal_split_pos > it->from(), "cannot split at start of interval");
5202
5203 if (optimal_split_pos == it->to() && it->next_usage(mustHaveRegister, min_split_pos) == max_jint) {
5204 // the split position would be just before the end of the interval
5205 // -> no split at all necessary
5206 TRACE_LINEAR_SCAN(4, tty->print_cr(" no split necessary because optimal split position is at end of interval"));
5207 return;
5208 }
5209
5210 // must calculate this before the actual split is performed and before split position is moved to odd op_id
5211 bool move_necessary = !allocator()->is_block_begin(optimal_split_pos) && !it->has_hole_between(optimal_split_pos - 1, optimal_split_pos);
5212
5213 if (!allocator()->is_block_begin(optimal_split_pos)) {
5214 // move position before actual instruction (odd op_id)
5215 optimal_split_pos = (optimal_split_pos - 1) | 1;
5216 }
5217
5218 TRACE_LINEAR_SCAN(4, tty->print_cr(" splitting at position %d", optimal_split_pos));
5219 assert(allocator()->is_block_begin(optimal_split_pos) || (optimal_split_pos % 2 == 1), "split pos must be odd when not on block boundary");
5220 assert(!allocator()->is_block_begin(optimal_split_pos) || (optimal_split_pos % 2 == 0), "split pos must be even on block boundary");
5221
5222 Interval* split_part = it->split(optimal_split_pos);
5223
5224 allocator()->append_interval(split_part);
5225 allocator()->copy_register_flags(it, split_part);
5226 split_part->set_insert_move_when_activated(move_necessary);
5227 append_to_unhandled(unhandled_first_addr(anyKind), split_part);
5228
5229 TRACE_LINEAR_SCAN(2, tty->print_cr(" split interval in two parts (insert_move_when_activated: %d)", move_necessary));
5230 TRACE_LINEAR_SCAN(2, tty->print (" "); it->print());
5231 TRACE_LINEAR_SCAN(2, tty->print (" "); split_part->print());
5232 }
5233
5234 /*
5235 split an interval at the optimal position between min_split_pos and
5236 max_split_pos in two parts:
5237 1) the left part has already a location assigned
5238 2) the right part is always on the stack and therefore ignored in further processing
5239 */
5240 void LinearScanWalker::split_for_spilling(Interval* it) {
5241 // calculate allowed range of splitting position
5242 int max_split_pos = current_position();
5243 int min_split_pos = MAX2(it->previous_usage(shouldHaveRegister, max_split_pos) + 1, it->from());
5244
5245 TRACE_LINEAR_SCAN(2, tty->print ("----- splitting and spilling interval: "); it->print());
5246 TRACE_LINEAR_SCAN(2, tty->print_cr(" between %d and %d", min_split_pos, max_split_pos));
5247
5248 assert(it->state() == activeState, "why spill interval that is not active?");
5249 assert(it->from() <= min_split_pos, "cannot split before start of interval");
5250 assert(min_split_pos <= max_split_pos, "invalid order");
5251 assert(max_split_pos < it->to(), "cannot split at end end of interval");
5252 assert(current_position() < it->to(), "interval must not end before current position");
5253
5254 if (min_split_pos == it->from()) {
5255 // the whole interval is never used, so spill it entirely to memory
5256 TRACE_LINEAR_SCAN(2, tty->print_cr(" spilling entire interval because split pos is at beginning of interval"));
5257 assert(it->first_usage(shouldHaveRegister) > current_position(), "interval must not have use position before current_position");
5258
5259 allocator()->assign_spill_slot(it);
5260 allocator()->change_spill_state(it, min_split_pos);
5261
5262 // Also kick parent intervals out of register to memory when they have no use
5263 // position. This avoids short interval in register surrounded by intervals in
5264 // memory -> avoid useless moves from memory to register and back
5265 Interval* parent = it;
5266 while (parent != nullptr && parent->is_split_child()) {
5267 parent = parent->split_child_before_op_id(parent->from());
5268
5269 if (parent->assigned_reg() < LinearScan::nof_regs) {
5270 if (parent->first_usage(shouldHaveRegister) == max_jint) {
5271 // parent is never used, so kick it out of its assigned register
5272 TRACE_LINEAR_SCAN(4, tty->print_cr(" kicking out interval %d out of its register because it is never used", parent->reg_num()));
5273 allocator()->assign_spill_slot(parent);
5274 } else {
5275 // do not go further back because the register is actually used by the interval
5276 parent = nullptr;
5277 }
5278 }
5279 }
5280
5281 } else {
5282 // search optimal split pos, split interval and spill only the right hand part
5283 int optimal_split_pos = find_optimal_split_pos(it, min_split_pos, max_split_pos, false);
5284
5285 assert(min_split_pos <= optimal_split_pos && optimal_split_pos <= max_split_pos, "out of range");
5286 assert(optimal_split_pos < it->to(), "cannot split at end of interval");
5287 assert(optimal_split_pos >= it->from(), "cannot split before start of interval");
5288
5289 if (!allocator()->is_block_begin(optimal_split_pos)) {
5290 // move position before actual instruction (odd op_id)
5291 optimal_split_pos = (optimal_split_pos - 1) | 1;
5292 }
5293
5294 TRACE_LINEAR_SCAN(4, tty->print_cr(" splitting at position %d", optimal_split_pos));
5295 assert(allocator()->is_block_begin(optimal_split_pos) || (optimal_split_pos % 2 == 1), "split pos must be odd when not on block boundary");
5296 assert(!allocator()->is_block_begin(optimal_split_pos) || (optimal_split_pos % 2 == 0), "split pos must be even on block boundary");
5297
5298 Interval* spilled_part = it->split(optimal_split_pos);
5299 allocator()->append_interval(spilled_part);
5300 allocator()->assign_spill_slot(spilled_part);
5301 allocator()->change_spill_state(spilled_part, optimal_split_pos);
5302
5303 if (!allocator()->is_block_begin(optimal_split_pos)) {
5304 TRACE_LINEAR_SCAN(4, tty->print_cr(" inserting move from interval %d to %d", it->reg_num(), spilled_part->reg_num()));
5305 insert_move(optimal_split_pos, it, spilled_part);
5306 }
5307
5308 // the current_split_child is needed later when moves are inserted for reloading
5309 assert(spilled_part->current_split_child() == it, "overwriting wrong current_split_child");
5310 spilled_part->make_current_split_child();
5311
5312 TRACE_LINEAR_SCAN(2, tty->print_cr(" split interval in two parts"));
5313 TRACE_LINEAR_SCAN(2, tty->print (" "); it->print());
5314 TRACE_LINEAR_SCAN(2, tty->print (" "); spilled_part->print());
5315 }
5316 }
5317
5318
5319 void LinearScanWalker::split_stack_interval(Interval* it) {
5320 int min_split_pos = current_position() + 1;
5321 int max_split_pos = MIN2(it->first_usage(shouldHaveRegister), it->to());
5322
5323 split_before_usage(it, min_split_pos, max_split_pos);
5324 }
5325
5326 void LinearScanWalker::split_when_partial_register_available(Interval* it, int register_available_until) {
5327 int min_split_pos = MAX2(it->previous_usage(shouldHaveRegister, register_available_until), it->from() + 1);
5328 int max_split_pos = register_available_until;
5329
5330 split_before_usage(it, min_split_pos, max_split_pos);
5331 }
5332
5333 void LinearScanWalker::split_and_spill_interval(Interval* it) {
5334 assert(it->state() == activeState || it->state() == inactiveState, "other states not allowed");
5335
5336 int current_pos = current_position();
5337 if (it->state() == inactiveState) {
5338 // the interval is currently inactive, so no spill slot is needed for now.
5339 // when the split part is activated, the interval has a new chance to get a register,
5340 // so in the best case no stack slot is necessary
5341 assert(it->has_hole_between(current_pos - 1, current_pos + 1), "interval can not be inactive otherwise");
5342 split_before_usage(it, current_pos + 1, current_pos + 1);
5343
5344 } else {
5345 // search the position where the interval must have a register and split
5346 // at the optimal position before.
5347 // The new created part is added to the unhandled list and will get a register
5348 // when it is activated
5349 int min_split_pos = current_pos + 1;
5350 int max_split_pos = MIN2(it->next_usage(mustHaveRegister, min_split_pos), it->to());
5351
5352 split_before_usage(it, min_split_pos, max_split_pos);
5353
5354 assert(it->next_usage(mustHaveRegister, current_pos) == max_jint, "the remaining part is spilled to stack and therefore has no register");
5355 split_for_spilling(it);
5356 }
5357 }
5358
5359 int LinearScanWalker::find_free_reg(int reg_needed_until, int interval_to, int hint_reg, int ignore_reg, bool* need_split) {
5360 int min_full_reg = any_reg;
5361 int max_partial_reg = any_reg;
5362
5363 for (int i = _first_reg; i <= _last_reg; i++) {
5364 if (i == ignore_reg) {
5365 // this register must be ignored
5366
5367 } else if (_use_pos[i] >= interval_to) {
5368 // this register is free for the full interval
5369 if (min_full_reg == any_reg || i == hint_reg || (_use_pos[i] < _use_pos[min_full_reg] && min_full_reg != hint_reg)) {
5370 min_full_reg = i;
5371 }
5372 } else if (_use_pos[i] > reg_needed_until) {
5373 // this register is at least free until reg_needed_until
5374 if (max_partial_reg == any_reg || i == hint_reg || (_use_pos[i] > _use_pos[max_partial_reg] && max_partial_reg != hint_reg)) {
5375 max_partial_reg = i;
5376 }
5377 }
5378 }
5379
5380 if (min_full_reg != any_reg) {
5381 return min_full_reg;
5382 } else if (max_partial_reg != any_reg) {
5383 *need_split = true;
5384 return max_partial_reg;
5385 } else {
5386 return any_reg;
5387 }
5388 }
5389
5390 int LinearScanWalker::find_free_double_reg(int reg_needed_until, int interval_to, int hint_reg, bool* need_split) {
5391 assert((_last_reg - _first_reg + 1) % 2 == 0, "adjust algorithm");
5392
5393 int min_full_reg = any_reg;
5394 int max_partial_reg = any_reg;
5395
5396 for (int i = _first_reg; i < _last_reg; i+=2) {
5397 if (_use_pos[i] >= interval_to && _use_pos[i + 1] >= interval_to) {
5398 // this register is free for the full interval
5399 if (min_full_reg == any_reg || i == hint_reg || (_use_pos[i] < _use_pos[min_full_reg] && min_full_reg != hint_reg)) {
5400 min_full_reg = i;
5401 }
5402 } else if (_use_pos[i] > reg_needed_until && _use_pos[i + 1] > reg_needed_until) {
5403 // this register is at least free until reg_needed_until
5404 if (max_partial_reg == any_reg || i == hint_reg || (_use_pos[i] > _use_pos[max_partial_reg] && max_partial_reg != hint_reg)) {
5405 max_partial_reg = i;
5406 }
5407 }
5408 }
5409
5410 if (min_full_reg != any_reg) {
5411 return min_full_reg;
5412 } else if (max_partial_reg != any_reg) {
5413 *need_split = true;
5414 return max_partial_reg;
5415 } else {
5416 return any_reg;
5417 }
5418 }
5419
5420 bool LinearScanWalker::alloc_free_reg(Interval* cur) {
5421 TRACE_LINEAR_SCAN(2, tty->print("trying to find free register for "); cur->print());
5422
5423 init_use_lists(true);
5424 free_exclude_active_fixed();
5425 free_exclude_active_any();
5426 free_collect_inactive_fixed(cur);
5427 free_collect_inactive_any(cur);
5428 assert(unhandled_first(fixedKind) == Interval::end(), "must not have unhandled fixed intervals because all fixed intervals have a use at position 0");
5429
5430 // _use_pos contains the start of the next interval that has this register assigned
5431 // (either as a fixed register or a normal allocated register in the past)
5432 // only intervals overlapping with cur are processed, non-overlapping invervals can be ignored safely
5433 #ifdef ASSERT
5434 if (TraceLinearScanLevel >= 4) {
5435 tty->print_cr(" state of registers:");
5436 for (int i = _first_reg; i <= _last_reg; i++) {
5437 tty->print(" reg %d (", i);
5438 LinearScan::print_reg_num(i);
5439 tty->print_cr("): use_pos: %d", _use_pos[i]);
5440 }
5441 }
5442 #endif
5443
5444 int hint_reg, hint_regHi;
5445 Interval* register_hint = cur->register_hint();
5446 if (register_hint != nullptr) {
5447 hint_reg = register_hint->assigned_reg();
5448 hint_regHi = register_hint->assigned_regHi();
5449
5450 if (_num_phys_regs == 2 && allocator()->is_precolored_cpu_interval(register_hint)) {
5451 assert(hint_reg != any_reg && hint_regHi == any_reg, "must be for fixed intervals");
5452 hint_regHi = hint_reg + 1; // connect e.g. eax-edx
5453 }
5454 #ifdef ASSERT
5455 if (TraceLinearScanLevel >= 4) {
5456 tty->print(" hint registers %d (", hint_reg);
5457 LinearScan::print_reg_num(hint_reg);
5458 tty->print("), %d (", hint_regHi);
5459 LinearScan::print_reg_num(hint_regHi);
5460 tty->print(") from interval ");
5461 register_hint->print();
5462 }
5463 #endif
5464 } else {
5465 hint_reg = any_reg;
5466 hint_regHi = any_reg;
5467 }
5468 assert(hint_reg == any_reg || hint_reg != hint_regHi, "hint reg and regHi equal");
5469 assert(cur->assigned_reg() == any_reg && cur->assigned_regHi() == any_reg, "register already assigned to interval");
5470
5471 // the register must be free at least until this position
5472 int reg_needed_until = cur->from() + 1;
5473 int interval_to = cur->to();
5474
5475 bool need_split = false;
5476 int split_pos;
5477 int reg;
5478 int regHi = any_reg;
5479
5480 if (_adjacent_regs) {
5481 reg = find_free_double_reg(reg_needed_until, interval_to, hint_reg, &need_split);
5482 regHi = reg + 1;
5483 if (reg == any_reg) {
5484 return false;
5485 }
5486 split_pos = MIN2(_use_pos[reg], _use_pos[regHi]);
5487
5488 } else {
5489 reg = find_free_reg(reg_needed_until, interval_to, hint_reg, any_reg, &need_split);
5490 if (reg == any_reg) {
5491 return false;
5492 }
5493 split_pos = _use_pos[reg];
5494
5495 if (_num_phys_regs == 2) {
5496 regHi = find_free_reg(reg_needed_until, interval_to, hint_regHi, reg, &need_split);
5497
5498 if (_use_pos[reg] < interval_to && regHi == any_reg) {
5499 // do not split interval if only one register can be assigned until the split pos
5500 // (when one register is found for the whole interval, split&spill is only
5501 // performed for the hi register)
5502 return false;
5503
5504 } else if (regHi != any_reg) {
5505 split_pos = MIN2(split_pos, _use_pos[regHi]);
5506
5507 // sort register numbers to prevent e.g. a move from eax,ebx to ebx,eax
5508 if (reg > regHi) {
5509 int temp = reg;
5510 reg = regHi;
5511 regHi = temp;
5512 }
5513 }
5514 }
5515 }
5516
5517 cur->assign_reg(reg, regHi);
5518 #ifdef ASSERT
5519 if (TraceLinearScanLevel >= 2) {
5520 tty->print(" selected registers %d (", reg);
5521 LinearScan::print_reg_num(reg);
5522 tty->print("), %d (", regHi);
5523 LinearScan::print_reg_num(regHi);
5524 tty->print_cr(")");
5525 }
5526 #endif
5527 assert(split_pos > 0, "invalid split_pos");
5528 if (need_split) {
5529 // register not available for full interval, so split it
5530 split_when_partial_register_available(cur, split_pos);
5531 }
5532
5533 // only return true if interval is completely assigned
5534 return _num_phys_regs == 1 || regHi != any_reg;
5535 }
5536
5537
5538 int LinearScanWalker::find_locked_reg(int reg_needed_until, int interval_to, int ignore_reg, bool* need_split) {
5539 int max_reg = any_reg;
5540
5541 for (int i = _first_reg; i <= _last_reg; i++) {
5542 if (i == ignore_reg) {
5543 // this register must be ignored
5544
5545 } else if (_use_pos[i] > reg_needed_until) {
5546 if (max_reg == any_reg || _use_pos[i] > _use_pos[max_reg]) {
5547 max_reg = i;
5548 }
5549 }
5550 }
5551
5552 if (max_reg != any_reg && _block_pos[max_reg] <= interval_to) {
5553 *need_split = true;
5554 }
5555
5556 return max_reg;
5557 }
5558
5559 int LinearScanWalker::find_locked_double_reg(int reg_needed_until, int interval_to, bool* need_split) {
5560 assert((_last_reg - _first_reg + 1) % 2 == 0, "adjust algorithm");
5561
5562 int max_reg = any_reg;
5563
5564 for (int i = _first_reg; i < _last_reg; i+=2) {
5565 if (_use_pos[i] > reg_needed_until && _use_pos[i + 1] > reg_needed_until) {
5566 if (max_reg == any_reg || _use_pos[i] > _use_pos[max_reg]) {
5567 max_reg = i;
5568 }
5569 }
5570 }
5571
5572 if (max_reg != any_reg &&
5573 (_block_pos[max_reg] <= interval_to || _block_pos[max_reg + 1] <= interval_to)) {
5574 *need_split = true;
5575 }
5576
5577 return max_reg;
5578 }
5579
5580 void LinearScanWalker::split_and_spill_intersecting_intervals(int reg, int regHi) {
5581 assert(reg != any_reg, "no register assigned");
5582
5583 for (int i = 0; i < _spill_intervals[reg]->length(); i++) {
5584 Interval* it = _spill_intervals[reg]->at(i);
5585 remove_from_list(it);
5586 split_and_spill_interval(it);
5587 }
5588
5589 if (regHi != any_reg) {
5590 IntervalList* processed = _spill_intervals[reg];
5591 for (int i = 0; i < _spill_intervals[regHi]->length(); i++) {
5592 Interval* it = _spill_intervals[regHi]->at(i);
5593 if (processed->find(it) == -1) {
5594 remove_from_list(it);
5595 split_and_spill_interval(it);
5596 }
5597 }
5598 }
5599 }
5600
5601
5602 // Split an Interval and spill it to memory so that cur can be placed in a register
5603 void LinearScanWalker::alloc_locked_reg(Interval* cur) {
5604 TRACE_LINEAR_SCAN(2, tty->print("need to split and spill to get register for "); cur->print());
5605
5606 // collect current usage of registers
5607 init_use_lists(false);
5608 spill_exclude_active_fixed();
5609 assert(unhandled_first(fixedKind) == Interval::end(), "must not have unhandled fixed intervals because all fixed intervals have a use at position 0");
5610 spill_block_inactive_fixed(cur);
5611 spill_collect_active_any();
5612 spill_collect_inactive_any(cur);
5613
5614 #ifdef ASSERT
5615 if (TraceLinearScanLevel >= 4) {
5616 tty->print_cr(" state of registers:");
5617 for (int i = _first_reg; i <= _last_reg; i++) {
5618 tty->print(" reg %d(", i);
5619 LinearScan::print_reg_num(i);
5620 tty->print("): use_pos: %d, block_pos: %d, intervals: ", _use_pos[i], _block_pos[i]);
5621 for (int j = 0; j < _spill_intervals[i]->length(); j++) {
5622 tty->print("%d ", _spill_intervals[i]->at(j)->reg_num());
5623 }
5624 tty->cr();
5625 }
5626 }
5627 #endif
5628
5629 // the register must be free at least until this position
5630 int reg_needed_until = MIN2(cur->first_usage(mustHaveRegister), cur->from() + 1);
5631 int interval_to = cur->to();
5632 assert (reg_needed_until > 0 && reg_needed_until < max_jint, "interval has no use");
5633
5634 int split_pos = 0;
5635 int use_pos = 0;
5636 bool need_split = false;
5637 int reg, regHi;
5638
5639 if (_adjacent_regs) {
5640 reg = find_locked_double_reg(reg_needed_until, interval_to, &need_split);
5641 regHi = reg + 1;
5642
5643 if (reg != any_reg) {
5644 use_pos = MIN2(_use_pos[reg], _use_pos[regHi]);
5645 split_pos = MIN2(_block_pos[reg], _block_pos[regHi]);
5646 }
5647 } else {
5648 reg = find_locked_reg(reg_needed_until, interval_to, cur->assigned_reg(), &need_split);
5649 regHi = any_reg;
5650
5651 if (reg != any_reg) {
5652 use_pos = _use_pos[reg];
5653 split_pos = _block_pos[reg];
5654
5655 if (_num_phys_regs == 2) {
5656 if (cur->assigned_reg() != any_reg) {
5657 regHi = reg;
5658 reg = cur->assigned_reg();
5659 } else {
5660 regHi = find_locked_reg(reg_needed_until, interval_to, reg, &need_split);
5661 if (regHi != any_reg) {
5662 use_pos = MIN2(use_pos, _use_pos[regHi]);
5663 split_pos = MIN2(split_pos, _block_pos[regHi]);
5664 }
5665 }
5666
5667 if (regHi != any_reg && reg > regHi) {
5668 // sort register numbers to prevent e.g. a move from eax,ebx to ebx,eax
5669 int temp = reg;
5670 reg = regHi;
5671 regHi = temp;
5672 }
5673 }
5674 }
5675 }
5676
5677 if (reg == any_reg || (_num_phys_regs == 2 && regHi == any_reg) || use_pos <= cur->first_usage(mustHaveRegister)) {
5678 // the first use of cur is later than the spilling position -> spill cur
5679 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));
5680
5681 if (cur->first_usage(mustHaveRegister) <= cur->from() + 1) {
5682 assert(false, "cannot spill interval that is used in first instruction (possible reason: no register found)");
5683 // assign a reasonable register and do a bailout in product mode to avoid errors
5684 allocator()->assign_spill_slot(cur);
5685 BAILOUT("LinearScan: no register found");
5686 }
5687
5688 split_and_spill_interval(cur);
5689 } else {
5690 #ifdef ASSERT
5691 if (TraceLinearScanLevel >= 4) {
5692 tty->print("decided to use register %d (", reg);
5693 LinearScan::print_reg_num(reg);
5694 tty->print("), %d (", regHi);
5695 LinearScan::print_reg_num(regHi);
5696 tty->print_cr(")");
5697 }
5698 #endif
5699 assert(reg != any_reg && (_num_phys_regs == 1 || regHi != any_reg), "no register found");
5700 assert(split_pos > 0, "invalid split_pos");
5701 assert(need_split == false || split_pos > cur->from(), "splitting interval at from");
5702
5703 cur->assign_reg(reg, regHi);
5704 if (need_split) {
5705 // register not available for full interval, so split it
5706 split_when_partial_register_available(cur, split_pos);
5707 }
5708
5709 // perform splitting and spilling for all affected intervals
5710 split_and_spill_intersecting_intervals(reg, regHi);
5711 }
5712 }
5713
5714 bool LinearScanWalker::no_allocation_possible(Interval* cur) {
5715 #ifdef X86
5716 // fast calculation of intervals that can never get a register because the
5717 // the next instruction is a call that blocks all registers
5718 // Note: this does not work if callee-saved registers are available (e.g. on Sparc)
5719
5720 // check if this interval is the result of a split operation
5721 // (an interval got a register until this position)
5722 int pos = cur->from();
5723 if ((pos & 1) == 1) {
5724 // the current instruction is a call that blocks all registers
5725 if (pos < allocator()->max_lir_op_id() && allocator()->has_call(pos + 1)) {
5726 TRACE_LINEAR_SCAN(4, tty->print_cr(" free register cannot be available because all registers blocked by following call"));
5727
5728 // safety check that there is really no register available
5729 assert(alloc_free_reg(cur) == false, "found a register for this interval");
5730 return true;
5731 }
5732
5733 }
5734 #endif
5735 return false;
5736 }
5737
5738 void LinearScanWalker::init_vars_for_alloc(Interval* cur) {
5739 BasicType type = cur->type();
5740 _num_phys_regs = LinearScan::num_physical_regs(type);
5741 _adjacent_regs = LinearScan::requires_adjacent_regs(type);
5742
5743 if (pd_init_regs_for_alloc(cur)) {
5744 // the appropriate register range was selected.
5745 } else if (type == T_FLOAT || type == T_DOUBLE) {
5746 _first_reg = pd_first_fpu_reg;
5747 _last_reg = pd_last_fpu_reg;
5748 } else {
5749 _first_reg = pd_first_cpu_reg;
5750 _last_reg = FrameMap::last_cpu_reg();
5751 }
5752
5753 assert(0 <= _first_reg && _first_reg < LinearScan::nof_regs, "out of range");
5754 assert(0 <= _last_reg && _last_reg < LinearScan::nof_regs, "out of range");
5755 }
5756
5757
5758 bool LinearScanWalker::is_move(LIR_Op* op, Interval* from, Interval* to) {
5759 if (op->code() != lir_move) {
5760 return false;
5761 }
5762 assert(op->as_Op1() != nullptr, "move must be LIR_Op1");
5763
5764 LIR_Opr in = ((LIR_Op1*)op)->in_opr();
5765 LIR_Opr res = ((LIR_Op1*)op)->result_opr();
5766 return in->is_virtual() && res->is_virtual() && in->vreg_number() == from->reg_num() && res->vreg_number() == to->reg_num();
5767 }
5768
5769 // optimization (especially for phi functions of nested loops):
5770 // assign same spill slot to non-intersecting intervals
5771 void LinearScanWalker::combine_spilled_intervals(Interval* cur) {
5772 if (cur->is_split_child()) {
5773 // optimization is only suitable for split parents
5774 return;
5775 }
5776
5777 Interval* register_hint = cur->register_hint(false);
5778 if (register_hint == nullptr) {
5779 // cur is not the target of a move, otherwise register_hint would be set
5780 return;
5781 }
5782 assert(register_hint->is_split_parent(), "register hint must be split parent");
5783
5784 if (cur->spill_state() != noOptimization || register_hint->spill_state() != noOptimization) {
5785 // combining the stack slots for intervals where spill move optimization is applied
5786 // is not benefitial and would cause problems
5787 return;
5788 }
5789
5790 int begin_pos = cur->from();
5791 int end_pos = cur->to();
5792 if (end_pos > allocator()->max_lir_op_id() || (begin_pos & 1) != 0 || (end_pos & 1) != 0) {
5793 // safety check that lir_op_with_id is allowed
5794 return;
5795 }
5796
5797 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)) {
5798 // cur and register_hint are not connected with two moves
5799 return;
5800 }
5801
5802 Interval* begin_hint = register_hint->split_child_at_op_id(begin_pos, LIR_OpVisitState::inputMode);
5803 Interval* end_hint = register_hint->split_child_at_op_id(end_pos, LIR_OpVisitState::outputMode);
5804 if (begin_hint == end_hint || begin_hint->to() != begin_pos || end_hint->from() != end_pos) {
5805 // register_hint must be split, otherwise the re-writing of use positions does not work
5806 return;
5807 }
5808
5809 assert(begin_hint->assigned_reg() != any_reg, "must have register assigned");
5810 assert(end_hint->assigned_reg() == any_reg, "must not have register assigned");
5811 assert(cur->first_usage(mustHaveRegister) == begin_pos, "must have use position at begin of interval because of move");
5812 assert(end_hint->first_usage(mustHaveRegister) == end_pos, "must have use position at begin of interval because of move");
5813
5814 if (begin_hint->assigned_reg() < LinearScan::nof_regs) {
5815 // register_hint is not spilled at begin_pos, so it would not be benefitial to immediately spill cur
5816 return;
5817 }
5818 assert(register_hint->canonical_spill_slot() != -1, "must be set when part of interval was spilled");
5819 assert(!cur->intersects(register_hint), "cur should not intersect register_hint");
5820
5821 if (cur->intersects_any_children_of(register_hint)) {
5822 // Bail out if cur intersects any split children of register_hint, which have the same spill slot as their parent. An overlap of two intervals with
5823 // the same spill slot could result in a situation where both intervals are spilled at the same time to the same stack location which is not correct.
5824 return;
5825 }
5826
5827 // modify intervals such that cur gets the same stack slot as register_hint
5828 // delete use positions to prevent the intervals to get a register at beginning
5829 cur->set_canonical_spill_slot(register_hint->canonical_spill_slot());
5830 cur->remove_first_use_pos();
5831 end_hint->remove_first_use_pos();
5832 }
5833
5834
5835 // allocate a physical register or memory location to an interval
5836 bool LinearScanWalker::activate_current() {
5837 Interval* cur = current();
5838 bool result = true;
5839
5840 TRACE_LINEAR_SCAN(2, tty->print ("+++++ activating interval "); cur->print());
5841 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()));
5842
5843 if (cur->assigned_reg() >= LinearScan::nof_regs) {
5844 // activating an interval that has a stack slot assigned -> split it at first use position
5845 // used for method parameters
5846 TRACE_LINEAR_SCAN(4, tty->print_cr(" interval has spill slot assigned (method parameter) -> split it before first use"));
5847
5848 split_stack_interval(cur);
5849 result = false;
5850
5851 } else if (allocator()->gen()->is_vreg_flag_set(cur->reg_num(), LIRGenerator::must_start_in_memory)) {
5852 // activating an interval that must start in a stack slot, but may get a register later
5853 TRACE_LINEAR_SCAN(4, tty->print_cr(" interval must start in stack slot -> split it before first use"));
5854 assert(cur->assigned_reg() == any_reg && cur->assigned_regHi() == any_reg, "register already assigned");
5855
5856 allocator()->assign_spill_slot(cur);
5857 split_stack_interval(cur);
5858 result = false;
5859
5860 } else if (cur->assigned_reg() == any_reg) {
5861 // interval has not assigned register -> normal allocation
5862 // (this is the normal case for most intervals)
5863 TRACE_LINEAR_SCAN(4, tty->print_cr(" normal allocation of register"));
5864
5865 // assign same spill slot to non-intersecting intervals
5866 combine_spilled_intervals(cur);
5867
5868 init_vars_for_alloc(cur);
5869 if (no_allocation_possible(cur) || !alloc_free_reg(cur)) {
5870 // no empty register available.
5871 // split and spill another interval so that this interval gets a register
5872 alloc_locked_reg(cur);
5873 }
5874
5875 // spilled intervals need not be move to active-list
5876 if (cur->assigned_reg() >= LinearScan::nof_regs) {
5877 result = false;
5878 }
5879 }
5880
5881 // load spilled values that become active from stack slot to register
5882 if (cur->insert_move_when_activated()) {
5883 assert(cur->is_split_child(), "must be");
5884 assert(cur->current_split_child() != nullptr, "must be");
5885 assert(cur->current_split_child()->reg_num() != cur->reg_num(), "cannot insert move between same interval");
5886 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()));
5887
5888 insert_move(cur->from(), cur->current_split_child(), cur);
5889 }
5890 cur->make_current_split_child();
5891
5892 return result; // true = interval is moved to active list
5893 }
5894
5895
5896 // Implementation of EdgeMoveOptimizer
5897
5898 EdgeMoveOptimizer::EdgeMoveOptimizer() :
5899 _edge_instructions(4),
5900 _edge_instructions_idx(4)
5901 {
5902 }
5903
5904 void EdgeMoveOptimizer::optimize(BlockList* code) {
5905 EdgeMoveOptimizer optimizer = EdgeMoveOptimizer();
5906
5907 // ignore the first block in the list (index 0 is not processed)
5908 for (int i = code->length() - 1; i >= 1; i--) {
5909 BlockBegin* block = code->at(i);
5910
5911 if (block->number_of_preds() > 1 && !block->is_set(BlockBegin::exception_entry_flag)) {
5912 optimizer.optimize_moves_at_block_end(block);
5913 }
5914 if (block->number_of_sux() == 2) {
5915 optimizer.optimize_moves_at_block_begin(block);
5916 }
5917 }
5918 }
5919
5920
5921 // clear all internal data structures
5922 void EdgeMoveOptimizer::init_instructions() {
5923 _edge_instructions.clear();
5924 _edge_instructions_idx.clear();
5925 }
5926
5927 // append a lir-instruction-list and the index of the current operation in to the list
5928 void EdgeMoveOptimizer::append_instructions(LIR_OpList* instructions, int instructions_idx) {
5929 _edge_instructions.append(instructions);
5930 _edge_instructions_idx.append(instructions_idx);
5931 }
5932
5933 // return the current operation of the given edge (predecessor or successor)
5934 LIR_Op* EdgeMoveOptimizer::instruction_at(int edge) {
5935 LIR_OpList* instructions = _edge_instructions.at(edge);
5936 int idx = _edge_instructions_idx.at(edge);
5937
5938 if (idx < instructions->length()) {
5939 return instructions->at(idx);
5940 } else {
5941 return nullptr;
5942 }
5943 }
5944
5945 // removes the current operation of the given edge (predecessor or successor)
5946 void EdgeMoveOptimizer::remove_cur_instruction(int edge, bool decrement_index) {
5947 LIR_OpList* instructions = _edge_instructions.at(edge);
5948 int idx = _edge_instructions_idx.at(edge);
5949 instructions->remove_at(idx);
5950
5951 if (decrement_index) {
5952 _edge_instructions_idx.at_put(edge, idx - 1);
5953 }
5954 }
5955
5956
5957 bool EdgeMoveOptimizer::operations_different(LIR_Op* op1, LIR_Op* op2) {
5958 if (op1 == nullptr || op2 == nullptr) {
5959 // at least one block is already empty -> no optimization possible
5960 return true;
5961 }
5962
5963 if (op1->code() == lir_move && op2->code() == lir_move) {
5964 assert(op1->as_Op1() != nullptr, "move must be LIR_Op1");
5965 assert(op2->as_Op1() != nullptr, "move must be LIR_Op1");
5966 LIR_Op1* move1 = (LIR_Op1*)op1;
5967 LIR_Op1* move2 = (LIR_Op1*)op2;
5968 if (move1->info() == move2->info() && move1->in_opr() == move2->in_opr() && move1->result_opr() == move2->result_opr()) {
5969 // these moves are exactly equal and can be optimized
5970 return false;
5971 }
5972 }
5973
5974 // no optimization possible
5975 return true;
5976 }
5977
5978 void EdgeMoveOptimizer::optimize_moves_at_block_end(BlockBegin* block) {
5979 TRACE_LINEAR_SCAN(4, tty->print_cr("optimizing moves at end of block B%d", block->block_id()));
5980
5981 if (block->is_predecessor(block)) {
5982 // currently we can't handle this correctly.
5983 return;
5984 }
5985
5986 init_instructions();
5987 int num_preds = block->number_of_preds();
5988 assert(num_preds > 1, "do not call otherwise");
5989 assert(!block->is_set(BlockBegin::exception_entry_flag), "exception handlers not allowed");
5990
5991 // setup a list with the lir-instructions of all predecessors
5992 int i;
5993 for (i = 0; i < num_preds; i++) {
5994 BlockBegin* pred = block->pred_at(i);
5995 LIR_OpList* pred_instructions = pred->lir()->instructions_list();
5996
5997 if (pred->number_of_sux() != 1) {
5998 // this can happen with switch-statements where multiple edges are between
5999 // the same blocks.
6000 return;
6001 }
6002
6003 assert(pred->number_of_sux() == 1, "can handle only one successor");
6004 assert(pred->sux_at(0) == block, "invalid control flow");
6005 assert(pred_instructions->last()->code() == lir_branch, "block with successor must end with branch");
6006 assert(pred_instructions->last()->as_OpBranch() != nullptr, "branch must be LIR_OpBranch");
6007 assert(pred_instructions->last()->as_OpBranch()->cond() == lir_cond_always, "block must end with unconditional branch");
6008
6009 if (pred_instructions->last()->info() != nullptr) {
6010 // can not optimize instructions when debug info is needed
6011 return;
6012 }
6013
6014 // ignore the unconditional branch at the end of the block
6015 append_instructions(pred_instructions, pred_instructions->length() - 2);
6016 }
6017
6018
6019 // process lir-instructions while all predecessors end with the same instruction
6020 while (true) {
6021 LIR_Op* op = instruction_at(0);
6022 for (i = 1; i < num_preds; i++) {
6023 if (operations_different(op, instruction_at(i))) {
6024 // these instructions are different and cannot be optimized ->
6025 // no further optimization possible
6026 return;
6027 }
6028 }
6029
6030 TRACE_LINEAR_SCAN(4, tty->print("found instruction that is equal in all %d predecessors: ", num_preds); op->print());
6031
6032 // insert the instruction at the beginning of the current block
6033 block->lir()->insert_before(1, op);
6034
6035 // delete the instruction at the end of all predecessors
6036 for (i = 0; i < num_preds; i++) {
6037 remove_cur_instruction(i, true);
6038 }
6039 }
6040 }
6041
6042
6043 void EdgeMoveOptimizer::optimize_moves_at_block_begin(BlockBegin* block) {
6044 TRACE_LINEAR_SCAN(4, tty->print_cr("optimization moves at begin of block B%d", block->block_id()));
6045
6046 init_instructions();
6047 int num_sux = block->number_of_sux();
6048
6049 LIR_OpList* cur_instructions = block->lir()->instructions_list();
6050
6051 assert(num_sux == 2, "method should not be called otherwise");
6052 assert(cur_instructions->last()->code() == lir_branch, "block with successor must end with branch");
6053 assert(cur_instructions->last()->as_OpBranch() != nullptr, "branch must be LIR_OpBranch");
6054 assert(cur_instructions->last()->as_OpBranch()->cond() == lir_cond_always, "block must end with unconditional branch");
6055
6056 if (cur_instructions->last()->info() != nullptr) {
6057 // can no optimize instructions when debug info is needed
6058 return;
6059 }
6060
6061 LIR_Op* branch = cur_instructions->at(cur_instructions->length() - 2);
6062 if (branch->info() != nullptr || (branch->code() != lir_branch && branch->code() != lir_cond_float_branch)) {
6063 // not a valid case for optimization
6064 // currently, only blocks that end with two branches (conditional branch followed
6065 // by unconditional branch) are optimized
6066 return;
6067 }
6068
6069 // now it is guaranteed that the block ends with two branch instructions.
6070 // the instructions are inserted at the end of the block before these two branches
6071 int insert_idx = cur_instructions->length() - 2;
6072
6073 int i;
6074 #ifdef ASSERT
6075 for (i = insert_idx - 1; i >= 0; i--) {
6076 LIR_Op* op = cur_instructions->at(i);
6077 if ((op->code() == lir_branch || op->code() == lir_cond_float_branch) && ((LIR_OpBranch*)op)->block() != nullptr) {
6078 assert(false, "block with two successors can have only two branch instructions");
6079 }
6080 }
6081 #endif
6082
6083 // setup a list with the lir-instructions of all successors
6084 for (i = 0; i < num_sux; i++) {
6085 BlockBegin* sux = block->sux_at(i);
6086 LIR_OpList* sux_instructions = sux->lir()->instructions_list();
6087
6088 assert(sux_instructions->at(0)->code() == lir_label, "block must start with label");
6089
6090 if (sux->number_of_preds() != 1) {
6091 // this can happen with switch-statements where multiple edges are between
6092 // the same blocks.
6093 return;
6094 }
6095 assert(sux->pred_at(0) == block, "invalid control flow");
6096 assert(!sux->is_set(BlockBegin::exception_entry_flag), "exception handlers not allowed");
6097
6098 // ignore the label at the beginning of the block
6099 append_instructions(sux_instructions, 1);
6100 }
6101
6102 // process lir-instructions while all successors begin with the same instruction
6103 while (true) {
6104 LIR_Op* op = instruction_at(0);
6105 for (i = 1; i < num_sux; i++) {
6106 if (operations_different(op, instruction_at(i))) {
6107 // these instructions are different and cannot be optimized ->
6108 // no further optimization possible
6109 return;
6110 }
6111 }
6112
6113 TRACE_LINEAR_SCAN(4, tty->print("----- found instruction that is equal in all %d successors: ", num_sux); op->print());
6114
6115 // insert instruction at end of current block
6116 block->lir()->insert_before(insert_idx, op);
6117 insert_idx++;
6118
6119 // delete the instructions at the beginning of all successors
6120 for (i = 0; i < num_sux; i++) {
6121 remove_cur_instruction(i, false);
6122 }
6123 }
6124 }
6125
6126
6127 // Implementation of ControlFlowOptimizer
6128
6129 ControlFlowOptimizer::ControlFlowOptimizer() :
6130 _original_preds(4)
6131 {
6132 }
6133
6134 void ControlFlowOptimizer::optimize(BlockList* code) {
6135 ControlFlowOptimizer optimizer = ControlFlowOptimizer();
6136
6137 // push the OSR entry block to the end so that we're not jumping over it.
6138 BlockBegin* osr_entry = code->at(0)->end()->as_Base()->osr_entry();
6139 if (osr_entry) {
6140 int index = osr_entry->linear_scan_number();
6141 assert(code->at(index) == osr_entry, "wrong index");
6142 code->remove_at(index);
6143 code->append(osr_entry);
6144 }
6145
6146 optimizer.reorder_short_loops(code);
6147 optimizer.delete_empty_blocks(code);
6148 optimizer.delete_unnecessary_jumps(code);
6149 optimizer.delete_jumps_to_return(code);
6150 }
6151
6152 void ControlFlowOptimizer::reorder_short_loop(BlockList* code, BlockBegin* header_block, int header_idx) {
6153 int i = header_idx + 1;
6154 int max_end = MIN2(header_idx + ShortLoopSize, code->length());
6155 while (i < max_end && code->at(i)->loop_depth() >= header_block->loop_depth()) {
6156 i++;
6157 }
6158
6159 if (i == code->length() || code->at(i)->loop_depth() < header_block->loop_depth()) {
6160 int end_idx = i - 1;
6161 BlockBegin* end_block = code->at(end_idx);
6162
6163 if (end_block->number_of_sux() == 1 && end_block->sux_at(0) == header_block) {
6164 // short loop from header_idx to end_idx found -> reorder blocks such that
6165 // the header_block is the last block instead of the first block of the loop
6166 TRACE_LINEAR_SCAN(1, tty->print_cr("Reordering short loop: length %d, header B%d, end B%d",
6167 end_idx - header_idx + 1,
6168 header_block->block_id(), end_block->block_id()));
6169
6170 for (int j = header_idx; j < end_idx; j++) {
6171 code->at_put(j, code->at(j + 1));
6172 }
6173 code->at_put(end_idx, header_block);
6174
6175 // correct the flags so that any loop alignment occurs in the right place.
6176 assert(code->at(end_idx)->is_set(BlockBegin::backward_branch_target_flag), "must be backward branch target");
6177 code->at(end_idx)->clear(BlockBegin::backward_branch_target_flag);
6178 code->at(header_idx)->set(BlockBegin::backward_branch_target_flag);
6179 }
6180 }
6181 }
6182
6183 void ControlFlowOptimizer::reorder_short_loops(BlockList* code) {
6184 for (int i = code->length() - 1; i >= 0; i--) {
6185 BlockBegin* block = code->at(i);
6186
6187 if (block->is_set(BlockBegin::linear_scan_loop_header_flag)) {
6188 reorder_short_loop(code, block, i);
6189 }
6190 }
6191
6192 DEBUG_ONLY(verify(code));
6193 }
6194
6195 // only blocks with exactly one successor can be deleted. Such blocks
6196 // must always end with an unconditional branch to this successor
6197 bool ControlFlowOptimizer::can_delete_block(BlockBegin* block) {
6198 if (block->number_of_sux() != 1 || block->number_of_exception_handlers() != 0 || block->is_entry_block()) {
6199 return false;
6200 }
6201
6202 LIR_OpList* instructions = block->lir()->instructions_list();
6203
6204 assert(instructions->length() >= 2, "block must have label and branch");
6205 assert(instructions->at(0)->code() == lir_label, "first instruction must always be a label");
6206 assert(instructions->last()->as_OpBranch() != nullptr, "last instruction must always be a branch");
6207 assert(instructions->last()->as_OpBranch()->cond() == lir_cond_always, "branch must be unconditional");
6208 assert(instructions->last()->as_OpBranch()->block() == block->sux_at(0), "branch target must be the successor");
6209
6210 // block must have exactly one successor
6211
6212 if (instructions->length() == 2 && instructions->last()->info() == nullptr) {
6213 return true;
6214 }
6215 return false;
6216 }
6217
6218 // substitute branch targets in all branch-instructions of this blocks
6219 void ControlFlowOptimizer::substitute_branch_target(BlockBegin* block, BlockBegin* target_from, BlockBegin* target_to) {
6220 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()));
6221
6222 LIR_OpList* instructions = block->lir()->instructions_list();
6223
6224 assert(instructions->at(0)->code() == lir_label, "first instruction must always be a label");
6225 for (int i = instructions->length() - 1; i >= 1; i--) {
6226 LIR_Op* op = instructions->at(i);
6227
6228 if (op->code() == lir_branch || op->code() == lir_cond_float_branch) {
6229 assert(op->as_OpBranch() != nullptr, "branch must be of type LIR_OpBranch");
6230 LIR_OpBranch* branch = (LIR_OpBranch*)op;
6231
6232 if (branch->block() == target_from) {
6233 branch->change_block(target_to);
6234 }
6235 if (branch->ublock() == target_from) {
6236 branch->change_ublock(target_to);
6237 }
6238 }
6239 }
6240 }
6241
6242 void ControlFlowOptimizer::delete_empty_blocks(BlockList* code) {
6243 int old_pos = 0;
6244 int new_pos = 0;
6245 int num_blocks = code->length();
6246
6247 while (old_pos < num_blocks) {
6248 BlockBegin* block = code->at(old_pos);
6249
6250 if (can_delete_block(block)) {
6251 BlockBegin* new_target = block->sux_at(0);
6252
6253 // propagate backward branch target flag for correct code alignment
6254 if (block->is_set(BlockBegin::backward_branch_target_flag)) {
6255 new_target->set(BlockBegin::backward_branch_target_flag);
6256 }
6257
6258 // collect a list with all predecessors that contains each predecessor only once
6259 // the predecessors of cur are changed during the substitution, so a copy of the
6260 // predecessor list is necessary
6261 int j;
6262 _original_preds.clear();
6263 for (j = block->number_of_preds() - 1; j >= 0; j--) {
6264 BlockBegin* pred = block->pred_at(j);
6265 if (_original_preds.find(pred) == -1) {
6266 _original_preds.append(pred);
6267 }
6268 }
6269
6270 for (j = _original_preds.length() - 1; j >= 0; j--) {
6271 BlockBegin* pred = _original_preds.at(j);
6272 substitute_branch_target(pred, block, new_target);
6273 pred->substitute_sux(block, new_target);
6274 }
6275 } else {
6276 // adjust position of this block in the block list if blocks before
6277 // have been deleted
6278 if (new_pos != old_pos) {
6279 code->at_put(new_pos, code->at(old_pos));
6280 }
6281 new_pos++;
6282 }
6283 old_pos++;
6284 }
6285 code->trunc_to(new_pos);
6286
6287 DEBUG_ONLY(verify(code));
6288 }
6289
6290 void ControlFlowOptimizer::delete_unnecessary_jumps(BlockList* code) {
6291 // skip the last block because there a branch is always necessary
6292 for (int i = code->length() - 2; i >= 0; i--) {
6293 BlockBegin* block = code->at(i);
6294 LIR_OpList* instructions = block->lir()->instructions_list();
6295
6296 LIR_Op* last_op = instructions->last();
6297 if (last_op->code() == lir_branch) {
6298 assert(last_op->as_OpBranch() != nullptr, "branch must be of type LIR_OpBranch");
6299 LIR_OpBranch* last_branch = (LIR_OpBranch*)last_op;
6300
6301 assert(last_branch->block() != nullptr, "last branch must always have a block as target");
6302 assert(last_branch->label() == last_branch->block()->label(), "must be equal");
6303
6304 if (last_branch->info() == nullptr) {
6305 if (last_branch->block() == code->at(i + 1)) {
6306
6307 TRACE_LINEAR_SCAN(3, tty->print_cr("Deleting unconditional branch at end of block B%d", block->block_id()));
6308
6309 // delete last branch instruction
6310 instructions->trunc_to(instructions->length() - 1);
6311
6312 } else {
6313 LIR_Op* prev_op = instructions->at(instructions->length() - 2);
6314 if (prev_op->code() == lir_branch || prev_op->code() == lir_cond_float_branch) {
6315 assert(prev_op->as_OpBranch() != nullptr, "branch must be of type LIR_OpBranch");
6316 LIR_OpBranch* prev_branch = (LIR_OpBranch*)prev_op;
6317
6318 if (prev_branch->stub() == nullptr) {
6319
6320 LIR_Op2* prev_cmp = nullptr;
6321 // There might be a cmove inserted for profiling which depends on the same
6322 // compare. If we change the condition of the respective compare, we have
6323 // to take care of this cmove as well.
6324 LIR_Op4* prev_cmove = nullptr;
6325
6326 for(int j = instructions->length() - 3; j >= 0 && prev_cmp == nullptr; j--) {
6327 prev_op = instructions->at(j);
6328 // check for the cmove
6329 if (prev_op->code() == lir_cmove) {
6330 assert(prev_op->as_Op4() != nullptr, "cmove must be of type LIR_Op4");
6331 prev_cmove = (LIR_Op4*)prev_op;
6332 assert(prev_branch->cond() == prev_cmove->condition(), "should be the same");
6333 }
6334 if (prev_op->code() == lir_cmp) {
6335 assert(prev_op->as_Op2() != nullptr, "branch must be of type LIR_Op2");
6336 prev_cmp = (LIR_Op2*)prev_op;
6337 assert(prev_branch->cond() == prev_cmp->condition(), "should be the same");
6338 }
6339 }
6340 // Guarantee because it is dereferenced below.
6341 guarantee(prev_cmp != nullptr, "should have found comp instruction for branch");
6342 if (prev_branch->block() == code->at(i + 1) && prev_branch->info() == nullptr) {
6343
6344 TRACE_LINEAR_SCAN(3, tty->print_cr("Negating conditional branch and deleting unconditional branch at end of block B%d", block->block_id()));
6345
6346 // eliminate a conditional branch to the immediate successor
6347 prev_branch->change_block(last_branch->block());
6348 prev_branch->negate_cond();
6349 prev_cmp->set_condition(prev_branch->cond());
6350 instructions->trunc_to(instructions->length() - 1);
6351 // if we do change the condition, we have to change the cmove as well
6352 if (prev_cmove != nullptr) {
6353 prev_cmove->set_condition(prev_branch->cond());
6354 LIR_Opr t = prev_cmove->in_opr1();
6355 prev_cmove->set_in_opr1(prev_cmove->in_opr2());
6356 prev_cmove->set_in_opr2(t);
6357 }
6358 }
6359 }
6360 }
6361 }
6362 }
6363 }
6364 }
6365
6366 DEBUG_ONLY(verify(code));
6367 }
6368
6369 void ControlFlowOptimizer::delete_jumps_to_return(BlockList* code) {
6370 #ifdef ASSERT
6371 ResourceBitMap return_converted(BlockBegin::number_of_blocks());
6372 #endif
6373
6374 for (int i = code->length() - 1; i >= 0; i--) {
6375 BlockBegin* block = code->at(i);
6376 LIR_OpList* cur_instructions = block->lir()->instructions_list();
6377 LIR_Op* cur_last_op = cur_instructions->last();
6378
6379 assert(cur_instructions->at(0)->code() == lir_label, "first instruction must always be a label");
6380 if (cur_instructions->length() == 2 && cur_last_op->code() == lir_return) {
6381 // the block contains only a label and a return
6382 // if a predecessor ends with an unconditional jump to this block, then the jump
6383 // can be replaced with a return instruction
6384 //
6385 // Note: the original block with only a return statement cannot be deleted completely
6386 // because the predecessors might have other (conditional) jumps to this block
6387 // -> this may lead to unnecessary return instructions in the final code
6388
6389 assert(cur_last_op->info() == nullptr, "return instructions do not have debug information");
6390 assert(block->number_of_sux() == 0 ||
6391 (return_converted.at(block->block_id()) && block->number_of_sux() == 1),
6392 "blocks that end with return must not have successors");
6393
6394 assert(cur_last_op->as_Op1() != nullptr, "return must be LIR_Op1");
6395 LIR_Opr return_opr = ((LIR_Op1*)cur_last_op)->in_opr();
6396
6397 for (int j = block->number_of_preds() - 1; j >= 0; j--) {
6398 BlockBegin* pred = block->pred_at(j);
6399 LIR_OpList* pred_instructions = pred->lir()->instructions_list();
6400 LIR_Op* pred_last_op = pred_instructions->last();
6401
6402 if (pred_last_op->code() == lir_branch) {
6403 assert(pred_last_op->as_OpBranch() != nullptr, "branch must be LIR_OpBranch");
6404 LIR_OpBranch* pred_last_branch = (LIR_OpBranch*)pred_last_op;
6405
6406 if (pred_last_branch->block() == block && pred_last_branch->cond() == lir_cond_always && pred_last_branch->info() == nullptr) {
6407 // replace the jump to a return with a direct return
6408 // Note: currently the edge between the blocks is not deleted
6409 pred_instructions->at_put(pred_instructions->length() - 1, new LIR_OpReturn(return_opr));
6410 #ifdef ASSERT
6411 return_converted.set_bit(pred->block_id());
6412 #endif
6413 }
6414 }
6415 }
6416 }
6417 }
6418 }
6419
6420
6421 #ifdef ASSERT
6422 void ControlFlowOptimizer::verify(BlockList* code) {
6423 for (int i = 0; i < code->length(); i++) {
6424 BlockBegin* block = code->at(i);
6425 LIR_OpList* instructions = block->lir()->instructions_list();
6426
6427 int j;
6428 for (j = 0; j < instructions->length(); j++) {
6429 LIR_OpBranch* op_branch = instructions->at(j)->as_OpBranch();
6430
6431 if (op_branch != nullptr) {
6432 assert(op_branch->block() == nullptr || code->find(op_branch->block()) != -1, "branch target not valid");
6433 assert(op_branch->ublock() == nullptr || code->find(op_branch->ublock()) != -1, "branch target not valid");
6434 }
6435 }
6436
6437 for (j = 0; j < block->number_of_sux() - 1; j++) {
6438 BlockBegin* sux = block->sux_at(j);
6439 assert(code->find(sux) != -1, "successor not valid");
6440 }
6441
6442 for (j = 0; j < block->number_of_preds() - 1; j++) {
6443 BlockBegin* pred = block->pred_at(j);
6444 assert(code->find(pred) != -1, "successor not valid");
6445 }
6446 }
6447 }
6448 #endif
6449
6450
6451 #ifndef PRODUCT
6452
6453 // Implementation of LinearStatistic
6454
6455 const char* LinearScanStatistic::counter_name(int counter_idx) {
6456 switch (counter_idx) {
6457 case counter_method: return "compiled methods";
6458 case counter_fpu_method: return "methods using fpu";
6459 case counter_loop_method: return "methods with loops";
6460 case counter_exception_method:return "methods with xhandler";
6461
6462 case counter_loop: return "loops";
6463 case counter_block: return "blocks";
6464 case counter_loop_block: return "blocks inside loop";
6465 case counter_exception_block: return "exception handler entries";
6466 case counter_interval: return "intervals";
6467 case counter_fixed_interval: return "fixed intervals";
6468 case counter_range: return "ranges";
6469 case counter_fixed_range: return "fixed ranges";
6470 case counter_use_pos: return "use positions";
6471 case counter_fixed_use_pos: return "fixed use positions";
6472 case counter_spill_slots: return "spill slots";
6473
6474 // counter for classes of lir instructions
6475 case counter_instruction: return "total instructions";
6476 case counter_label: return "labels";
6477 case counter_entry: return "method entries";
6478 case counter_return: return "method returns";
6479 case counter_call: return "method calls";
6480 case counter_move: return "moves";
6481 case counter_cmp: return "compare";
6482 case counter_cond_branch: return "conditional branches";
6483 case counter_uncond_branch: return "unconditional branches";
6484 case counter_stub_branch: return "branches to stub";
6485 case counter_alu: return "artithmetic + logic";
6486 case counter_alloc: return "allocations";
6487 case counter_sync: return "synchronisation";
6488 case counter_throw: return "throw";
6489 case counter_unwind: return "unwind";
6490 case counter_typecheck: return "type+null-checks";
6491 case counter_misc_inst: return "other instructions";
6492 case counter_other_inst: return "misc. instructions";
6493
6494 // counter for different types of moves
6495 case counter_move_total: return "total moves";
6496 case counter_move_reg_reg: return "register->register";
6497 case counter_move_reg_stack: return "register->stack";
6498 case counter_move_stack_reg: return "stack->register";
6499 case counter_move_stack_stack:return "stack->stack";
6500 case counter_move_reg_mem: return "register->memory";
6501 case counter_move_mem_reg: return "memory->register";
6502 case counter_move_const_any: return "constant->any";
6503
6504 case blank_line_1: return "";
6505 case blank_line_2: return "";
6506
6507 default: ShouldNotReachHere(); return "";
6508 }
6509 }
6510
6511 LinearScanStatistic::Counter LinearScanStatistic::base_counter(int counter_idx) {
6512 if (counter_idx == counter_fpu_method || counter_idx == counter_loop_method || counter_idx == counter_exception_method) {
6513 return counter_method;
6514 } else if (counter_idx == counter_loop_block || counter_idx == counter_exception_block) {
6515 return counter_block;
6516 } else if (counter_idx >= counter_instruction && counter_idx <= counter_other_inst) {
6517 return counter_instruction;
6518 } else if (counter_idx >= counter_move_total && counter_idx <= counter_move_const_any) {
6519 return counter_move_total;
6520 }
6521 return invalid_counter;
6522 }
6523
6524 LinearScanStatistic::LinearScanStatistic() {
6525 for (int i = 0; i < number_of_counters; i++) {
6526 _counters_sum[i] = 0;
6527 _counters_max[i] = -1;
6528 }
6529
6530 }
6531
6532 // add the method-local numbers to the total sum
6533 void LinearScanStatistic::sum_up(LinearScanStatistic &method_statistic) {
6534 for (int i = 0; i < number_of_counters; i++) {
6535 _counters_sum[i] += method_statistic._counters_sum[i];
6536 _counters_max[i] = MAX2(_counters_max[i], method_statistic._counters_sum[i]);
6537 }
6538 }
6539
6540 void LinearScanStatistic::print(const char* title) {
6541 if (CountLinearScan || TraceLinearScanLevel > 0) {
6542 tty->cr();
6543 tty->print_cr("***** LinearScan statistic - %s *****", title);
6544
6545 for (int i = 0; i < number_of_counters; i++) {
6546 if (_counters_sum[i] > 0 || _counters_max[i] >= 0) {
6547 tty->print("%25s: %8d", counter_name(i), _counters_sum[i]);
6548
6549 LinearScanStatistic::Counter cntr = base_counter(i);
6550 if (cntr != invalid_counter) {
6551 tty->print(" (%5.1f%%) ", _counters_sum[i] * 100.0 / _counters_sum[cntr]);
6552 } else {
6553 tty->print(" ");
6554 }
6555
6556 if (_counters_max[i] >= 0) {
6557 tty->print("%8d", _counters_max[i]);
6558 }
6559 }
6560 tty->cr();
6561 }
6562 }
6563 }
6564
6565 void LinearScanStatistic::collect(LinearScan* allocator) {
6566 inc_counter(counter_method);
6567 if (allocator->has_fpu_registers()) {
6568 inc_counter(counter_fpu_method);
6569 }
6570 if (allocator->num_loops() > 0) {
6571 inc_counter(counter_loop_method);
6572 }
6573 inc_counter(counter_loop, allocator->num_loops());
6574 inc_counter(counter_spill_slots, allocator->max_spills());
6575
6576 int i;
6577 for (i = 0; i < allocator->interval_count(); i++) {
6578 Interval* cur = allocator->interval_at(i);
6579
6580 if (cur != nullptr) {
6581 inc_counter(counter_interval);
6582 inc_counter(counter_use_pos, cur->num_use_positions());
6583 if (LinearScan::is_precolored_interval(cur)) {
6584 inc_counter(counter_fixed_interval);
6585 inc_counter(counter_fixed_use_pos, cur->num_use_positions());
6586 }
6587
6588 Range* range = cur->first();
6589 while (range != Range::end()) {
6590 inc_counter(counter_range);
6591 if (LinearScan::is_precolored_interval(cur)) {
6592 inc_counter(counter_fixed_range);
6593 }
6594 range = range->next();
6595 }
6596 }
6597 }
6598
6599 bool has_xhandlers = false;
6600 // Note: only count blocks that are in code-emit order
6601 for (i = 0; i < allocator->ir()->code()->length(); i++) {
6602 BlockBegin* cur = allocator->ir()->code()->at(i);
6603
6604 inc_counter(counter_block);
6605 if (cur->loop_depth() > 0) {
6606 inc_counter(counter_loop_block);
6607 }
6608 if (cur->is_set(BlockBegin::exception_entry_flag)) {
6609 inc_counter(counter_exception_block);
6610 has_xhandlers = true;
6611 }
6612
6613 LIR_OpList* instructions = cur->lir()->instructions_list();
6614 for (int j = 0; j < instructions->length(); j++) {
6615 LIR_Op* op = instructions->at(j);
6616
6617 inc_counter(counter_instruction);
6618
6619 switch (op->code()) {
6620 case lir_label: inc_counter(counter_label); break;
6621 case lir_std_entry:
6622 case lir_osr_entry: inc_counter(counter_entry); break;
6623 case lir_return: inc_counter(counter_return); break;
6624
6625 case lir_rtcall:
6626 case lir_static_call:
6627 case lir_optvirtual_call: inc_counter(counter_call); break;
6628
6629 case lir_move: {
6630 inc_counter(counter_move);
6631 inc_counter(counter_move_total);
6632
6633 LIR_Opr in = op->as_Op1()->in_opr();
6634 LIR_Opr res = op->as_Op1()->result_opr();
6635 if (in->is_register()) {
6636 if (res->is_register()) {
6637 inc_counter(counter_move_reg_reg);
6638 } else if (res->is_stack()) {
6639 inc_counter(counter_move_reg_stack);
6640 } else if (res->is_address()) {
6641 inc_counter(counter_move_reg_mem);
6642 } else {
6643 ShouldNotReachHere();
6644 }
6645 } else if (in->is_stack()) {
6646 if (res->is_register()) {
6647 inc_counter(counter_move_stack_reg);
6648 } else {
6649 inc_counter(counter_move_stack_stack);
6650 }
6651 } else if (in->is_address()) {
6652 assert(res->is_register(), "must be");
6653 inc_counter(counter_move_mem_reg);
6654 } else if (in->is_constant()) {
6655 inc_counter(counter_move_const_any);
6656 } else {
6657 ShouldNotReachHere();
6658 }
6659 break;
6660 }
6661
6662 case lir_cmp: inc_counter(counter_cmp); break;
6663
6664 case lir_branch:
6665 case lir_cond_float_branch: {
6666 LIR_OpBranch* branch = op->as_OpBranch();
6667 if (branch->block() == nullptr) {
6668 inc_counter(counter_stub_branch);
6669 } else if (branch->cond() == lir_cond_always) {
6670 inc_counter(counter_uncond_branch);
6671 } else {
6672 inc_counter(counter_cond_branch);
6673 }
6674 break;
6675 }
6676
6677 case lir_neg:
6678 case lir_add:
6679 case lir_sub:
6680 case lir_mul:
6681 case lir_div:
6682 case lir_rem:
6683 case lir_sqrt:
6684 case lir_abs:
6685 case lir_f2hf:
6686 case lir_hf2f:
6687 case lir_logic_and:
6688 case lir_logic_or:
6689 case lir_logic_xor:
6690 case lir_shl:
6691 case lir_shr:
6692 case lir_ushr: inc_counter(counter_alu); break;
6693
6694 case lir_alloc_object:
6695 case lir_alloc_array: inc_counter(counter_alloc); break;
6696
6697 case lir_monaddr:
6698 case lir_lock:
6699 case lir_unlock: inc_counter(counter_sync); break;
6700
6701 case lir_throw: inc_counter(counter_throw); break;
6702
6703 case lir_unwind: inc_counter(counter_unwind); break;
6704
6705 case lir_null_check:
6706 case lir_leal:
6707 case lir_instanceof:
6708 case lir_checkcast:
6709 case lir_store_check: inc_counter(counter_typecheck); break;
6710
6711 case lir_nop:
6712 case lir_push:
6713 case lir_pop:
6714 case lir_convert:
6715 case lir_cmove: inc_counter(counter_misc_inst); break;
6716
6717 default: inc_counter(counter_other_inst); break;
6718 }
6719 }
6720 }
6721
6722 if (has_xhandlers) {
6723 inc_counter(counter_exception_method);
6724 }
6725 }
6726
6727 void LinearScanStatistic::compute(LinearScan* allocator, LinearScanStatistic &global_statistic) {
6728 if (CountLinearScan || TraceLinearScanLevel > 0) {
6729
6730 LinearScanStatistic local_statistic = LinearScanStatistic();
6731
6732 local_statistic.collect(allocator);
6733 global_statistic.sum_up(local_statistic);
6734
6735 if (TraceLinearScanLevel > 2) {
6736 local_statistic.print("current local statistic");
6737 }
6738 }
6739 }
6740
6741
6742 // Implementation of LinearTimers
6743
6744 LinearScanTimers::LinearScanTimers() {
6745 for (int i = 0; i < number_of_timers; i++) {
6746 timer(i)->reset();
6747 }
6748 }
6749
6750 const char* LinearScanTimers::timer_name(int idx) {
6751 switch (idx) {
6752 case timer_do_nothing: return "Nothing (Time Check)";
6753 case timer_number_instructions: return "Number Instructions";
6754 case timer_compute_local_live_sets: return "Local Live Sets";
6755 case timer_compute_global_live_sets: return "Global Live Sets";
6756 case timer_build_intervals: return "Build Intervals";
6757 case timer_sort_intervals_before: return "Sort Intervals Before";
6758 case timer_allocate_registers: return "Allocate Registers";
6759 case timer_resolve_data_flow: return "Resolve Data Flow";
6760 case timer_sort_intervals_after: return "Sort Intervals After";
6761 case timer_eliminate_spill_moves: return "Spill optimization";
6762 case timer_assign_reg_num: return "Assign Reg Num";
6763 case timer_optimize_lir: return "Optimize LIR";
6764 default: ShouldNotReachHere(); return "";
6765 }
6766 }
6767
6768 void LinearScanTimers::begin_method() {
6769 if (TimeEachLinearScan) {
6770 // reset all timers to measure only current method
6771 for (int i = 0; i < number_of_timers; i++) {
6772 timer(i)->reset();
6773 }
6774 }
6775 }
6776
6777 void LinearScanTimers::end_method(LinearScan* allocator) {
6778 if (TimeEachLinearScan) {
6779
6780 double c = timer(timer_do_nothing)->seconds();
6781 double total = 0;
6782 for (int i = 1; i < number_of_timers; i++) {
6783 total += timer(i)->seconds() - c;
6784 }
6785
6786 if (total >= 0.0005) {
6787 // print all information in one line for automatic processing
6788 tty->print("@"); allocator->compilation()->method()->print_name();
6789
6790 tty->print("@ %d ", allocator->compilation()->method()->code_size());
6791 tty->print("@ %d ", allocator->block_at(allocator->block_count() - 1)->last_lir_instruction_id() / 2);
6792 tty->print("@ %d ", allocator->block_count());
6793 tty->print("@ %d ", allocator->num_virtual_regs());
6794 tty->print("@ %d ", allocator->interval_count());
6795 tty->print("@ %d ", allocator->_num_calls);
6796 tty->print("@ %d ", allocator->num_loops());
6797
6798 tty->print("@ %6.6f ", total);
6799 for (int i = 1; i < number_of_timers; i++) {
6800 tty->print("@ %4.1f ", ((timer(i)->seconds() - c) / total) * 100);
6801 }
6802 tty->cr();
6803 }
6804 }
6805 }
6806
6807 void LinearScanTimers::print(double total_time) {
6808 if (TimeLinearScan) {
6809 // correction value: sum of dummy-timer that only measures the time that
6810 // is necessary to start and stop itself
6811 double c = timer(timer_do_nothing)->seconds();
6812
6813 for (int i = 0; i < number_of_timers; i++) {
6814 double t = timer(i)->seconds();
6815 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);
6816 }
6817 }
6818 }
6819
6820 #endif // #ifndef PRODUCT