1 /*
2 * Copyright (c) 2005, 2011, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "c1/c1_CFGPrinter.hpp"
27 #include "c1/c1_CodeStubs.hpp"
28 #include "c1/c1_Compilation.hpp"
29 #include "c1/c1_FrameMap.hpp"
30 #include "c1/c1_IR.hpp"
31 #include "c1/c1_LIRGenerator.hpp"
32 #include "c1/c1_LinearScan.hpp"
33 #include "c1/c1_ValueStack.hpp"
34 #include "utilities/bitMap.inline.hpp"
35 #ifdef TARGET_ARCH_x86
36 # include "vmreg_x86.inline.hpp"
37 #endif
38 #ifdef TARGET_ARCH_sparc
39 # include "vmreg_sparc.inline.hpp"
40 #endif
41 #ifdef TARGET_ARCH_zero
42 # include "vmreg_zero.inline.hpp"
43 #endif
44 #ifdef TARGET_ARCH_arm
45 # include "vmreg_arm.inline.hpp"
46 #endif
47 #ifdef TARGET_ARCH_ppc
48 # include "vmreg_ppc.inline.hpp"
49 #endif
50
51
52 #ifndef PRODUCT
53
54 static LinearScanStatistic _stat_before_alloc;
55 static LinearScanStatistic _stat_after_asign;
56 static LinearScanStatistic _stat_final;
57
58 static LinearScanTimers _total_timer;
59
60 // helper macro for short definition of timer
61 #define TIME_LINEAR_SCAN(timer_name) TraceTime _block_timer("", _total_timer.timer(LinearScanTimers::timer_name), TimeLinearScan || TimeEachLinearScan, Verbose);
62
63 // helper macro for short definition of trace-output inside code
64 #define TRACE_LINEAR_SCAN(level, code) \
65 if (TraceLinearScanLevel >= level) { \
66 code; \
67 }
68
69 #else
70
71 #define TIME_LINEAR_SCAN(timer_name)
72 #define TRACE_LINEAR_SCAN(level, code)
73
74 #endif
75
76 // Map BasicType to spill size in 32-bit words, matching VMReg's notion of words
77 #ifdef _LP64
78 static int type2spill_size[T_CONFLICT+1]={ -1, 0, 0, 0, 1, 1, 1, 2, 1, 1, 1, 2, 2, 2, 0, 1, -1};
79 #else
80 static int type2spill_size[T_CONFLICT+1]={ -1, 0, 0, 0, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 0, 1, -1};
81 #endif
82
83
84 // Implementation of LinearScan
85
86 LinearScan::LinearScan(IR* ir, LIRGenerator* gen, FrameMap* frame_map)
87 : _compilation(ir->compilation())
88 , _ir(ir)
89 , _gen(gen)
90 , _frame_map(frame_map)
91 , _num_virtual_regs(gen->max_virtual_register_number())
92 , _has_fpu_registers(false)
93 , _num_calls(-1)
94 , _max_spills(0)
95 , _unused_spill_slot(-1)
96 , _intervals(0) // initialized later with correct length
97 , _new_intervals_from_allocation(new IntervalList())
98 , _sorted_intervals(NULL)
99 , _needs_full_resort(false)
100 , _lir_ops(0) // initialized later with correct length
101 , _block_of_op(0) // initialized later with correct length
102 , _has_info(0)
103 , _has_call(0)
104 , _scope_value_cache(0) // initialized later with correct length
105 , _interval_in_loop(0, 0) // initialized later with correct length
106 , _cached_blocks(*ir->linear_scan_order())
107 #ifdef X86
108 , _fpu_stack_allocator(NULL)
109 #endif
110 {
111 assert(this->ir() != NULL, "check if valid");
112 assert(this->compilation() != NULL, "check if valid");
113 assert(this->gen() != NULL, "check if valid");
114 assert(this->frame_map() != NULL, "check if valid");
115 }
116
117
118 // ********** functions for converting LIR-Operands to register numbers
119 //
120 // Emulate a flat register file comprising physical integer registers,
121 // physical floating-point registers and virtual registers, in that order.
122 // Virtual registers already have appropriate numbers, since V0 is
123 // the number of physical registers.
124 // Returns -1 for hi word if opr is a single word operand.
125 //
126 // Note: the inverse operation (calculating an operand for register numbers)
127 // is done in calc_operand_for_interval()
128
129 int LinearScan::reg_num(LIR_Opr opr) {
130 assert(opr->is_register(), "should not call this otherwise");
131
132 if (opr->is_virtual_register()) {
133 assert(opr->vreg_number() >= nof_regs, "found a virtual register with a fixed-register number");
134 return opr->vreg_number();
135 } else if (opr->is_single_cpu()) {
136 return opr->cpu_regnr();
137 } else if (opr->is_double_cpu()) {
138 return opr->cpu_regnrLo();
139 #ifdef X86
140 } else if (opr->is_single_xmm()) {
141 return opr->fpu_regnr() + pd_first_xmm_reg;
142 } else if (opr->is_double_xmm()) {
143 return opr->fpu_regnrLo() + pd_first_xmm_reg;
144 #endif
145 } else if (opr->is_single_fpu()) {
146 return opr->fpu_regnr() + pd_first_fpu_reg;
147 } else if (opr->is_double_fpu()) {
148 return opr->fpu_regnrLo() + pd_first_fpu_reg;
149 } else {
150 ShouldNotReachHere();
151 return -1;
152 }
153 }
154
155 int LinearScan::reg_numHi(LIR_Opr opr) {
156 assert(opr->is_register(), "should not call this otherwise");
157
158 if (opr->is_virtual_register()) {
159 return -1;
160 } else if (opr->is_single_cpu()) {
161 return -1;
162 } else if (opr->is_double_cpu()) {
163 return opr->cpu_regnrHi();
164 #ifdef X86
165 } else if (opr->is_single_xmm()) {
166 return -1;
167 } else if (opr->is_double_xmm()) {
168 return -1;
169 #endif
170 } else if (opr->is_single_fpu()) {
171 return -1;
172 } else if (opr->is_double_fpu()) {
173 return opr->fpu_regnrHi() + pd_first_fpu_reg;
174 } else {
175 ShouldNotReachHere();
176 return -1;
177 }
178 }
179
180
181 // ********** functions for classification of intervals
182
183 bool LinearScan::is_precolored_interval(const Interval* i) {
184 return i->reg_num() < LinearScan::nof_regs;
185 }
186
187 bool LinearScan::is_virtual_interval(const Interval* i) {
188 return i->reg_num() >= LIR_OprDesc::vreg_base;
189 }
190
191 bool LinearScan::is_precolored_cpu_interval(const Interval* i) {
192 return i->reg_num() < LinearScan::nof_cpu_regs;
193 }
194
195 bool LinearScan::is_virtual_cpu_interval(const Interval* i) {
196 #if defined(__SOFTFP__) || defined(E500V2)
197 return i->reg_num() >= LIR_OprDesc::vreg_base;
198 #else
199 return i->reg_num() >= LIR_OprDesc::vreg_base && (i->type() != T_FLOAT && i->type() != T_DOUBLE);
200 #endif // __SOFTFP__ or E500V2
201 }
202
203 bool LinearScan::is_precolored_fpu_interval(const Interval* i) {
204 return i->reg_num() >= LinearScan::nof_cpu_regs && i->reg_num() < LinearScan::nof_regs;
205 }
206
207 bool LinearScan::is_virtual_fpu_interval(const Interval* i) {
208 #if defined(__SOFTFP__) || defined(E500V2)
209 return false;
210 #else
211 return i->reg_num() >= LIR_OprDesc::vreg_base && (i->type() == T_FLOAT || i->type() == T_DOUBLE);
212 #endif // __SOFTFP__ or E500V2
213 }
214
215 bool LinearScan::is_in_fpu_register(const Interval* i) {
216 // fixed intervals not needed for FPU stack allocation
217 return i->reg_num() >= nof_regs && pd_first_fpu_reg <= i->assigned_reg() && i->assigned_reg() <= pd_last_fpu_reg;
218 }
219
220 bool LinearScan::is_oop_interval(const Interval* i) {
221 // fixed intervals never contain oops
222 return i->reg_num() >= nof_regs && i->type() == T_OBJECT;
223 }
224
225
226 // ********** General helper functions
227
228 // compute next unused stack index that can be used for spilling
229 int LinearScan::allocate_spill_slot(bool double_word) {
230 int spill_slot;
231 if (double_word) {
232 if ((_max_spills & 1) == 1) {
233 // alignment of double-word values
234 // the hole because of the alignment is filled with the next single-word value
235 assert(_unused_spill_slot == -1, "wasting a spill slot");
236 _unused_spill_slot = _max_spills;
237 _max_spills++;
238 }
239 spill_slot = _max_spills;
240 _max_spills += 2;
241
242 } else if (_unused_spill_slot != -1) {
243 // re-use hole that was the result of a previous double-word alignment
244 spill_slot = _unused_spill_slot;
245 _unused_spill_slot = -1;
246
247 } else {
248 spill_slot = _max_spills;
249 _max_spills++;
250 }
251
252 int result = spill_slot + LinearScan::nof_regs + frame_map()->argcount();
253
254 // the class OopMapValue uses only 11 bits for storing the name of the
255 // oop location. So a stack slot bigger than 2^11 leads to an overflow
256 // that is not reported in product builds. Prevent this by checking the
257 // spill slot here (altough this value and the later used location name
258 // are slightly different)
259 if (result > 2000) {
260 bailout("too many stack slots used");
261 }
262
263 return result;
264 }
265
266 void LinearScan::assign_spill_slot(Interval* it) {
267 // assign the canonical spill slot of the parent (if a part of the interval
268 // is already spilled) or allocate a new spill slot
269 if (it->canonical_spill_slot() >= 0) {
270 it->assign_reg(it->canonical_spill_slot());
271 } else {
272 int spill = allocate_spill_slot(type2spill_size[it->type()] == 2);
273 it->set_canonical_spill_slot(spill);
274 it->assign_reg(spill);
275 }
276 }
277
278 void LinearScan::propagate_spill_slots() {
279 if (!frame_map()->finalize_frame(max_spills())) {
280 bailout("frame too large");
281 }
282 }
283
284 // create a new interval with a predefined reg_num
285 // (only used for parent intervals that are created during the building phase)
286 Interval* LinearScan::create_interval(int reg_num) {
287 assert(_intervals.at(reg_num) == NULL, "overwriting exisiting interval");
288
289 Interval* interval = new Interval(reg_num);
290 _intervals.at_put(reg_num, interval);
291
292 // assign register number for precolored intervals
293 if (reg_num < LIR_OprDesc::vreg_base) {
294 interval->assign_reg(reg_num);
295 }
296 return interval;
297 }
298
299 // assign a new reg_num to the interval and append it to the list of intervals
300 // (only used for child intervals that are created during register allocation)
301 void LinearScan::append_interval(Interval* it) {
302 it->set_reg_num(_intervals.length());
303 _intervals.append(it);
304 _new_intervals_from_allocation->append(it);
305 }
306
307 // copy the vreg-flags if an interval is split
308 void LinearScan::copy_register_flags(Interval* from, Interval* to) {
309 if (gen()->is_vreg_flag_set(from->reg_num(), LIRGenerator::byte_reg)) {
310 gen()->set_vreg_flag(to->reg_num(), LIRGenerator::byte_reg);
311 }
312 if (gen()->is_vreg_flag_set(from->reg_num(), LIRGenerator::callee_saved)) {
313 gen()->set_vreg_flag(to->reg_num(), LIRGenerator::callee_saved);
314 }
315
316 // Note: do not copy the must_start_in_memory flag because it is not necessary for child
317 // intervals (only the very beginning of the interval must be in memory)
318 }
319
320
321 // ********** spill move optimization
322 // eliminate moves from register to stack if stack slot is known to be correct
323
324 // called during building of intervals
325 void LinearScan::change_spill_definition_pos(Interval* interval, int def_pos) {
326 assert(interval->is_split_parent(), "can only be called for split parents");
327
328 switch (interval->spill_state()) {
329 case noDefinitionFound:
330 assert(interval->spill_definition_pos() == -1, "must no be set before");
331 interval->set_spill_definition_pos(def_pos);
332 interval->set_spill_state(oneDefinitionFound);
333 break;
334
335 case oneDefinitionFound:
336 assert(def_pos <= interval->spill_definition_pos(), "positions are processed in reverse order when intervals are created");
337 if (def_pos < interval->spill_definition_pos() - 2) {
338 // second definition found, so no spill optimization possible for this interval
339 interval->set_spill_state(noOptimization);
340 } else {
341 // two consecutive definitions (because of two-operand LIR form)
342 assert(block_of_op_with_id(def_pos) == block_of_op_with_id(interval->spill_definition_pos()), "block must be equal");
343 }
344 break;
345
346 case noOptimization:
347 // nothing to do
348 break;
349
350 default:
351 assert(false, "other states not allowed at this time");
352 }
353 }
354
355 // called during register allocation
356 void LinearScan::change_spill_state(Interval* interval, int spill_pos) {
357 switch (interval->spill_state()) {
358 case oneDefinitionFound: {
359 int def_loop_depth = block_of_op_with_id(interval->spill_definition_pos())->loop_depth();
360 int spill_loop_depth = block_of_op_with_id(spill_pos)->loop_depth();
361
362 if (def_loop_depth < spill_loop_depth) {
363 // the loop depth of the spilling position is higher then the loop depth
364 // at the definition of the interval -> move write to memory out of loop
365 // by storing at definitin of the interval
366 interval->set_spill_state(storeAtDefinition);
367 } else {
368 // the interval is currently spilled only once, so for now there is no
369 // reason to store the interval at the definition
370 interval->set_spill_state(oneMoveInserted);
371 }
372 break;
373 }
374
375 case oneMoveInserted: {
376 // the interval is spilled more then once, so it is better to store it to
377 // memory at the definition
378 interval->set_spill_state(storeAtDefinition);
379 break;
380 }
381
382 case storeAtDefinition:
383 case startInMemory:
384 case noOptimization:
385 case noDefinitionFound:
386 // nothing to do
387 break;
388
389 default:
390 assert(false, "other states not allowed at this time");
391 }
392 }
393
394
395 bool LinearScan::must_store_at_definition(const Interval* i) {
396 return i->is_split_parent() && i->spill_state() == storeAtDefinition;
397 }
398
399 // called once before asignment of register numbers
400 void LinearScan::eliminate_spill_moves() {
401 TIME_LINEAR_SCAN(timer_eliminate_spill_moves);
402 TRACE_LINEAR_SCAN(3, tty->print_cr("***** Eliminating unnecessary spill moves"));
403
404 // collect all intervals that must be stored after their definion.
405 // the list is sorted by Interval::spill_definition_pos
406 Interval* interval;
407 Interval* temp_list;
408 create_unhandled_lists(&interval, &temp_list, must_store_at_definition, NULL);
409
410 #ifdef ASSERT
411 Interval* prev = NULL;
412 Interval* temp = interval;
413 while (temp != Interval::end()) {
414 assert(temp->spill_definition_pos() > 0, "invalid spill definition pos");
415 if (prev != NULL) {
416 assert(temp->from() >= prev->from(), "intervals not sorted");
417 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");
418 }
419
420 assert(temp->canonical_spill_slot() >= LinearScan::nof_regs, "interval has no spill slot assigned");
421 assert(temp->spill_definition_pos() >= temp->from(), "invalid order");
422 assert(temp->spill_definition_pos() <= temp->from() + 2, "only intervals defined once at their start-pos can be optimized");
423
424 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()));
425
426 temp = temp->next();
427 }
428 #endif
429
430 LIR_InsertionBuffer insertion_buffer;
431 int num_blocks = block_count();
432 for (int i = 0; i < num_blocks; i++) {
433 BlockBegin* block = block_at(i);
434 LIR_OpList* instructions = block->lir()->instructions_list();
435 int num_inst = instructions->length();
436 bool has_new = false;
437
438 // iterate all instructions of the block. skip the first because it is always a label
439 for (int j = 1; j < num_inst; j++) {
440 LIR_Op* op = instructions->at(j);
441 int op_id = op->id();
442
443 if (op_id == -1) {
444 // remove move from register to stack if the stack slot is guaranteed to be correct.
445 // only moves that have been inserted by LinearScan can be removed.
446 assert(op->code() == lir_move, "only moves can have a op_id of -1");
447 assert(op->as_Op1() != NULL, "move must be LIR_Op1");
448 assert(op->as_Op1()->result_opr()->is_virtual(), "LinearScan inserts only moves to virtual registers");
449
450 LIR_Op1* op1 = (LIR_Op1*)op;
451 Interval* interval = interval_at(op1->result_opr()->vreg_number());
452
453 if (interval->assigned_reg() >= LinearScan::nof_regs && interval->always_in_memory()) {
454 // move target is a stack slot that is always correct, so eliminate instruction
455 TRACE_LINEAR_SCAN(4, tty->print_cr("eliminating move from interval %d to %d", op1->in_opr()->vreg_number(), op1->result_opr()->vreg_number()));
456 instructions->at_put(j, NULL); // NULL-instructions are deleted by assign_reg_num
457 }
458
459 } else {
460 // insert move from register to stack just after the beginning of the interval
461 assert(interval == Interval::end() || interval->spill_definition_pos() >= op_id, "invalid order");
462 assert(interval == Interval::end() || (interval->is_split_parent() && interval->spill_state() == storeAtDefinition), "invalid interval");
463
464 while (interval != Interval::end() && interval->spill_definition_pos() == op_id) {
465 if (!has_new) {
466 // prepare insertion buffer (appended when all instructions of the block are processed)
467 insertion_buffer.init(block->lir());
468 has_new = true;
469 }
470
471 LIR_Opr from_opr = operand_for_interval(interval);
472 LIR_Opr to_opr = canonical_spill_opr(interval);
473 assert(from_opr->is_fixed_cpu() || from_opr->is_fixed_fpu(), "from operand must be a register");
474 assert(to_opr->is_stack(), "to operand must be a stack slot");
475
476 insertion_buffer.move(j, from_opr, to_opr);
477 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));
478
479 interval = interval->next();
480 }
481 }
482 } // end of instruction iteration
483
484 if (has_new) {
485 block->lir()->append(&insertion_buffer);
486 }
487 } // end of block iteration
488
489 assert(interval == Interval::end(), "missed an interval");
490 }
491
492
493 // ********** Phase 1: number all instructions in all blocks
494 // Compute depth-first and linear scan block orders, and number LIR_Op nodes for linear scan.
495
496 void LinearScan::number_instructions() {
497 {
498 // dummy-timer to measure the cost of the timer itself
499 // (this time is then subtracted from all other timers to get the real value)
500 TIME_LINEAR_SCAN(timer_do_nothing);
501 }
502 TIME_LINEAR_SCAN(timer_number_instructions);
503
504 // Assign IDs to LIR nodes and build a mapping, lir_ops, from ID to LIR_Op node.
505 int num_blocks = block_count();
506 int num_instructions = 0;
507 int i;
508 for (i = 0; i < num_blocks; i++) {
509 num_instructions += block_at(i)->lir()->instructions_list()->length();
510 }
511
512 // initialize with correct length
513 _lir_ops = LIR_OpArray(num_instructions);
514 _block_of_op = BlockBeginArray(num_instructions);
515
516 int op_id = 0;
517 int idx = 0;
518
519 for (i = 0; i < num_blocks; i++) {
520 BlockBegin* block = block_at(i);
521 block->set_first_lir_instruction_id(op_id);
522 LIR_OpList* instructions = block->lir()->instructions_list();
523
524 int num_inst = instructions->length();
525 for (int j = 0; j < num_inst; j++) {
526 LIR_Op* op = instructions->at(j);
527 op->set_id(op_id);
528
529 _lir_ops.at_put(idx, op);
530 _block_of_op.at_put(idx, block);
531 assert(lir_op_with_id(op_id) == op, "must match");
532
533 idx++;
534 op_id += 2; // numbering of lir_ops by two
535 }
536 block->set_last_lir_instruction_id(op_id - 2);
537 }
538 assert(idx == num_instructions, "must match");
539 assert(idx * 2 == op_id, "must match");
540
541 _has_call = BitMap(num_instructions); _has_call.clear();
542 _has_info = BitMap(num_instructions); _has_info.clear();
543 }
544
545
546 // ********** Phase 2: compute local live sets separately for each block
547 // (sets live_gen and live_kill for each block)
548
549 void LinearScan::set_live_gen_kill(Value value, LIR_Op* op, BitMap& live_gen, BitMap& live_kill) {
550 LIR_Opr opr = value->operand();
551 Constant* con = value->as_Constant();
552
553 // check some asumptions about debug information
554 assert(!value->type()->is_illegal(), "if this local is used by the interpreter it shouldn't be of indeterminate type");
555 assert(con == NULL || opr->is_virtual() || opr->is_constant() || opr->is_illegal(), "asumption: Constant instructions have only constant operands");
556 assert(con != NULL || opr->is_virtual(), "asumption: non-Constant instructions have only virtual operands");
557
558 if ((con == NULL || con->is_pinned()) && opr->is_register()) {
559 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
560 int reg = opr->vreg_number();
561 if (!live_kill.at(reg)) {
562 live_gen.set_bit(reg);
563 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));
564 }
565 }
566 }
567
568
569 void LinearScan::compute_local_live_sets() {
570 TIME_LINEAR_SCAN(timer_compute_local_live_sets);
571
572 int num_blocks = block_count();
573 int live_size = live_set_size();
574 bool local_has_fpu_registers = false;
575 int local_num_calls = 0;
576 LIR_OpVisitState visitor;
577
578 BitMap2D local_interval_in_loop = BitMap2D(_num_virtual_regs, num_loops());
579 local_interval_in_loop.clear();
580
581 // iterate all blocks
582 for (int i = 0; i < num_blocks; i++) {
583 BlockBegin* block = block_at(i);
584
585 BitMap live_gen(live_size); live_gen.clear();
586 BitMap live_kill(live_size); live_kill.clear();
587
588 if (block->is_set(BlockBegin::exception_entry_flag)) {
589 // Phi functions at the begin of an exception handler are
590 // implicitly defined (= killed) at the beginning of the block.
591 for_each_phi_fun(block, phi,
592 live_kill.set_bit(phi->operand()->vreg_number())
593 );
594 }
595
596 LIR_OpList* instructions = block->lir()->instructions_list();
597 int num_inst = instructions->length();
598
599 // iterate all instructions of the block. skip the first because it is always a label
600 assert(visitor.no_operands(instructions->at(0)), "first operation must always be a label");
601 for (int j = 1; j < num_inst; j++) {
602 LIR_Op* op = instructions->at(j);
603
604 // visit operation to collect all operands
605 visitor.visit(op);
606
607 if (visitor.has_call()) {
608 _has_call.set_bit(op->id() >> 1);
609 local_num_calls++;
610 }
611 if (visitor.info_count() > 0) {
612 _has_info.set_bit(op->id() >> 1);
613 }
614
615 // iterate input operands of instruction
616 int k, n, reg;
617 n = visitor.opr_count(LIR_OpVisitState::inputMode);
618 for (k = 0; k < n; k++) {
619 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::inputMode, k);
620 assert(opr->is_register(), "visitor should only return register operands");
621
622 if (opr->is_virtual_register()) {
623 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
624 reg = opr->vreg_number();
625 if (!live_kill.at(reg)) {
626 live_gen.set_bit(reg);
627 TRACE_LINEAR_SCAN(4, tty->print_cr(" Setting live_gen for register %d at instruction %d", reg, op->id()));
628 }
629 if (block->loop_index() >= 0) {
630 local_interval_in_loop.set_bit(reg, block->loop_index());
631 }
632 local_has_fpu_registers = local_has_fpu_registers || opr->is_virtual_fpu();
633 }
634
635 #ifdef ASSERT
636 // fixed intervals are never live at block boundaries, so
637 // they need not be processed in live sets.
638 // this is checked by these assertions to be sure about it.
639 // the entry block may have incoming values in registers, which is ok.
640 if (!opr->is_virtual_register() && block != ir()->start()) {
641 reg = reg_num(opr);
642 if (is_processed_reg_num(reg)) {
643 assert(live_kill.at(reg), "using fixed register that is not defined in this block");
644 }
645 reg = reg_numHi(opr);
646 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
647 assert(live_kill.at(reg), "using fixed register that is not defined in this block");
648 }
649 }
650 #endif
651 }
652
653 // Add uses of live locals from interpreter's point of view for proper debug information generation
654 n = visitor.info_count();
655 for (k = 0; k < n; k++) {
656 CodeEmitInfo* info = visitor.info_at(k);
657 ValueStack* stack = info->stack();
658 for_each_state_value(stack, value,
659 set_live_gen_kill(value, op, live_gen, live_kill)
660 );
661 }
662
663 // iterate temp operands of instruction
664 n = visitor.opr_count(LIR_OpVisitState::tempMode);
665 for (k = 0; k < n; k++) {
666 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::tempMode, k);
667 assert(opr->is_register(), "visitor should only return register operands");
668
669 if (opr->is_virtual_register()) {
670 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
671 reg = opr->vreg_number();
672 live_kill.set_bit(reg);
673 if (block->loop_index() >= 0) {
674 local_interval_in_loop.set_bit(reg, block->loop_index());
675 }
676 local_has_fpu_registers = local_has_fpu_registers || opr->is_virtual_fpu();
677 }
678
679 #ifdef ASSERT
680 // fixed intervals are never live at block boundaries, so
681 // they need not be processed in live sets
682 // process them only in debug mode so that this can be checked
683 if (!opr->is_virtual_register()) {
684 reg = reg_num(opr);
685 if (is_processed_reg_num(reg)) {
686 live_kill.set_bit(reg_num(opr));
687 }
688 reg = reg_numHi(opr);
689 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
690 live_kill.set_bit(reg);
691 }
692 }
693 #endif
694 }
695
696 // iterate output operands of instruction
697 n = visitor.opr_count(LIR_OpVisitState::outputMode);
698 for (k = 0; k < n; k++) {
699 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::outputMode, k);
700 assert(opr->is_register(), "visitor should only return register operands");
701
702 if (opr->is_virtual_register()) {
703 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
704 reg = opr->vreg_number();
705 live_kill.set_bit(reg);
706 if (block->loop_index() >= 0) {
707 local_interval_in_loop.set_bit(reg, block->loop_index());
708 }
709 local_has_fpu_registers = local_has_fpu_registers || opr->is_virtual_fpu();
710 }
711
712 #ifdef ASSERT
713 // fixed intervals are never live at block boundaries, so
714 // they need not be processed in live sets
715 // process them only in debug mode so that this can be checked
716 if (!opr->is_virtual_register()) {
717 reg = reg_num(opr);
718 if (is_processed_reg_num(reg)) {
719 live_kill.set_bit(reg_num(opr));
720 }
721 reg = reg_numHi(opr);
722 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
723 live_kill.set_bit(reg);
724 }
725 }
726 #endif
727 }
728 } // end of instruction iteration
729
730 block->set_live_gen (live_gen);
731 block->set_live_kill(live_kill);
732 block->set_live_in (BitMap(live_size)); block->live_in().clear();
733 block->set_live_out (BitMap(live_size)); block->live_out().clear();
734
735 TRACE_LINEAR_SCAN(4, tty->print("live_gen B%d ", block->block_id()); print_bitmap(block->live_gen()));
736 TRACE_LINEAR_SCAN(4, tty->print("live_kill B%d ", block->block_id()); print_bitmap(block->live_kill()));
737 } // end of block iteration
738
739 // propagate local calculated information into LinearScan object
740 _has_fpu_registers = local_has_fpu_registers;
741 compilation()->set_has_fpu_code(local_has_fpu_registers);
742
743 _num_calls = local_num_calls;
744 _interval_in_loop = local_interval_in_loop;
745 }
746
747
748 // ********** Phase 3: perform a backward dataflow analysis to compute global live sets
749 // (sets live_in and live_out for each block)
750
751 void LinearScan::compute_global_live_sets() {
752 TIME_LINEAR_SCAN(timer_compute_global_live_sets);
753
754 int num_blocks = block_count();
755 bool change_occurred;
756 bool change_occurred_in_block;
757 int iteration_count = 0;
758 BitMap live_out(live_set_size()); live_out.clear(); // scratch set for calculations
759
760 // Perform a backward dataflow analysis to compute live_out and live_in for each block.
761 // The loop is executed until a fixpoint is reached (no changes in an iteration)
762 // Exception handlers must be processed because not all live values are
763 // present in the state array, e.g. because of global value numbering
764 do {
765 change_occurred = false;
766
767 // iterate all blocks in reverse order
768 for (int i = num_blocks - 1; i >= 0; i--) {
769 BlockBegin* block = block_at(i);
770
771 change_occurred_in_block = false;
772
773 // live_out(block) is the union of live_in(sux), for successors sux of block
774 int n = block->number_of_sux();
775 int e = block->number_of_exception_handlers();
776 if (n + e > 0) {
777 // block has successors
778 if (n > 0) {
779 live_out.set_from(block->sux_at(0)->live_in());
780 for (int j = 1; j < n; j++) {
781 live_out.set_union(block->sux_at(j)->live_in());
782 }
783 } else {
784 live_out.clear();
785 }
786 for (int j = 0; j < e; j++) {
787 live_out.set_union(block->exception_handler_at(j)->live_in());
788 }
789
790 if (!block->live_out().is_same(live_out)) {
791 // A change occurred. Swap the old and new live out sets to avoid copying.
792 BitMap temp = block->live_out();
793 block->set_live_out(live_out);
794 live_out = temp;
795
796 change_occurred = true;
797 change_occurred_in_block = true;
798 }
799 }
800
801 if (iteration_count == 0 || change_occurred_in_block) {
802 // live_in(block) is the union of live_gen(block) with (live_out(block) & !live_kill(block))
803 // note: live_in has to be computed only in first iteration or if live_out has changed!
804 BitMap live_in = block->live_in();
805 live_in.set_from(block->live_out());
806 live_in.set_difference(block->live_kill());
807 live_in.set_union(block->live_gen());
808 }
809
810 #ifndef PRODUCT
811 if (TraceLinearScanLevel >= 4) {
812 char c = ' ';
813 if (iteration_count == 0 || change_occurred_in_block) {
814 c = '*';
815 }
816 tty->print("(%d) live_in%c B%d ", iteration_count, c, block->block_id()); print_bitmap(block->live_in());
817 tty->print("(%d) live_out%c B%d ", iteration_count, c, block->block_id()); print_bitmap(block->live_out());
818 }
819 #endif
820 }
821 iteration_count++;
822
823 if (change_occurred && iteration_count > 50) {
824 BAILOUT("too many iterations in compute_global_live_sets");
825 }
826 } while (change_occurred);
827
828
829 #ifdef ASSERT
830 // check that fixed intervals are not live at block boundaries
831 // (live set must be empty at fixed intervals)
832 for (int i = 0; i < num_blocks; i++) {
833 BlockBegin* block = block_at(i);
834 for (int j = 0; j < LIR_OprDesc::vreg_base; j++) {
835 assert(block->live_in().at(j) == false, "live_in set of fixed register must be empty");
836 assert(block->live_out().at(j) == false, "live_out set of fixed register must be empty");
837 assert(block->live_gen().at(j) == false, "live_gen set of fixed register must be empty");
838 }
839 }
840 #endif
841
842 // check that the live_in set of the first block is empty
843 BitMap live_in_args(ir()->start()->live_in().size());
844 live_in_args.clear();
845 if (!ir()->start()->live_in().is_same(live_in_args)) {
846 #ifdef ASSERT
847 tty->print_cr("Error: live_in set of first block must be empty (when this fails, virtual registers are used before they are defined)");
848 tty->print_cr("affected registers:");
849 print_bitmap(ir()->start()->live_in());
850
851 // print some additional information to simplify debugging
852 for (unsigned int i = 0; i < ir()->start()->live_in().size(); i++) {
853 if (ir()->start()->live_in().at(i)) {
854 Instruction* instr = gen()->instruction_for_vreg(i);
855 tty->print_cr("* vreg %d (HIR instruction %c%d)", i, instr == NULL ? ' ' : instr->type()->tchar(), instr == NULL ? 0 : instr->id());
856
857 for (int j = 0; j < num_blocks; j++) {
858 BlockBegin* block = block_at(j);
859 if (block->live_gen().at(i)) {
860 tty->print_cr(" used in block B%d", block->block_id());
861 }
862 if (block->live_kill().at(i)) {
863 tty->print_cr(" defined in block B%d", block->block_id());
864 }
865 }
866 }
867 }
868
869 #endif
870 // when this fails, virtual registers are used before they are defined.
871 assert(false, "live_in set of first block must be empty");
872 // bailout of if this occurs in product mode.
873 bailout("live_in set of first block not empty");
874 }
875 }
876
877
878 // ********** Phase 4: build intervals
879 // (fills the list _intervals)
880
881 void LinearScan::add_use(Value value, int from, int to, IntervalUseKind use_kind) {
882 assert(!value->type()->is_illegal(), "if this value is used by the interpreter it shouldn't be of indeterminate type");
883 LIR_Opr opr = value->operand();
884 Constant* con = value->as_Constant();
885
886 if ((con == NULL || con->is_pinned()) && opr->is_register()) {
887 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
888 add_use(opr, from, to, use_kind);
889 }
890 }
891
892
893 void LinearScan::add_def(LIR_Opr opr, int def_pos, IntervalUseKind use_kind) {
894 TRACE_LINEAR_SCAN(2, tty->print(" def "); opr->print(tty); tty->print_cr(" def_pos %d (%d)", def_pos, use_kind));
895 assert(opr->is_register(), "should not be called otherwise");
896
897 if (opr->is_virtual_register()) {
898 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
899 add_def(opr->vreg_number(), def_pos, use_kind, opr->type_register());
900
901 } else {
902 int reg = reg_num(opr);
903 if (is_processed_reg_num(reg)) {
904 add_def(reg, def_pos, use_kind, opr->type_register());
905 }
906 reg = reg_numHi(opr);
907 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
908 add_def(reg, def_pos, use_kind, opr->type_register());
909 }
910 }
911 }
912
913 void LinearScan::add_use(LIR_Opr opr, int from, int to, IntervalUseKind use_kind) {
914 TRACE_LINEAR_SCAN(2, tty->print(" use "); opr->print(tty); tty->print_cr(" from %d to %d (%d)", from, to, use_kind));
915 assert(opr->is_register(), "should not be called otherwise");
916
917 if (opr->is_virtual_register()) {
918 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
919 add_use(opr->vreg_number(), from, to, use_kind, opr->type_register());
920
921 } else {
922 int reg = reg_num(opr);
923 if (is_processed_reg_num(reg)) {
924 add_use(reg, from, to, use_kind, opr->type_register());
925 }
926 reg = reg_numHi(opr);
927 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
928 add_use(reg, from, to, use_kind, opr->type_register());
929 }
930 }
931 }
932
933 void LinearScan::add_temp(LIR_Opr opr, int temp_pos, IntervalUseKind use_kind) {
934 TRACE_LINEAR_SCAN(2, tty->print(" temp "); opr->print(tty); tty->print_cr(" temp_pos %d (%d)", temp_pos, use_kind));
935 assert(opr->is_register(), "should not be called otherwise");
936
937 if (opr->is_virtual_register()) {
938 assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
939 add_temp(opr->vreg_number(), temp_pos, use_kind, opr->type_register());
940
941 } else {
942 int reg = reg_num(opr);
943 if (is_processed_reg_num(reg)) {
944 add_temp(reg, temp_pos, use_kind, opr->type_register());
945 }
946 reg = reg_numHi(opr);
947 if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
948 add_temp(reg, temp_pos, use_kind, opr->type_register());
949 }
950 }
951 }
952
953
954 void LinearScan::add_def(int reg_num, int def_pos, IntervalUseKind use_kind, BasicType type) {
955 Interval* interval = interval_at(reg_num);
956 if (interval != NULL) {
957 assert(interval->reg_num() == reg_num, "wrong interval");
958
959 if (type != T_ILLEGAL) {
960 interval->set_type(type);
961 }
962
963 Range* r = interval->first();
964 if (r->from() <= def_pos) {
965 // Update the starting point (when a range is first created for a use, its
966 // start is the beginning of the current block until a def is encountered.)
967 r->set_from(def_pos);
968 interval->add_use_pos(def_pos, use_kind);
969
970 } else {
971 // Dead value - make vacuous interval
972 // also add use_kind for dead intervals
973 interval->add_range(def_pos, def_pos + 1);
974 interval->add_use_pos(def_pos, use_kind);
975 TRACE_LINEAR_SCAN(2, tty->print_cr("Warning: def of reg %d at %d occurs without use", reg_num, def_pos));
976 }
977
978 } else {
979 // Dead value - make vacuous interval
980 // also add use_kind for dead intervals
981 interval = create_interval(reg_num);
982 if (type != T_ILLEGAL) {
983 interval->set_type(type);
984 }
985
986 interval->add_range(def_pos, def_pos + 1);
987 interval->add_use_pos(def_pos, use_kind);
988 TRACE_LINEAR_SCAN(2, tty->print_cr("Warning: dead value %d at %d in live intervals", reg_num, def_pos));
989 }
990
991 change_spill_definition_pos(interval, def_pos);
992 if (use_kind == noUse && interval->spill_state() <= startInMemory) {
993 // detection of method-parameters and roundfp-results
994 // TODO: move this directly to position where use-kind is computed
995 interval->set_spill_state(startInMemory);
996 }
997 }
998
999 void LinearScan::add_use(int reg_num, int from, int to, IntervalUseKind use_kind, BasicType type) {
1000 Interval* interval = interval_at(reg_num);
1001 if (interval == NULL) {
1002 interval = create_interval(reg_num);
1003 }
1004 assert(interval->reg_num() == reg_num, "wrong interval");
1005
1006 if (type != T_ILLEGAL) {
1007 interval->set_type(type);
1008 }
1009
1010 interval->add_range(from, to);
1011 interval->add_use_pos(to, use_kind);
1012 }
1013
1014 void LinearScan::add_temp(int reg_num, int temp_pos, IntervalUseKind use_kind, BasicType type) {
1015 Interval* interval = interval_at(reg_num);
1016 if (interval == NULL) {
1017 interval = create_interval(reg_num);
1018 }
1019 assert(interval->reg_num() == reg_num, "wrong interval");
1020
1021 if (type != T_ILLEGAL) {
1022 interval->set_type(type);
1023 }
1024
1025 interval->add_range(temp_pos, temp_pos + 1);
1026 interval->add_use_pos(temp_pos, use_kind);
1027 }
1028
1029
1030 // the results of this functions are used for optimizing spilling and reloading
1031 // if the functions return shouldHaveRegister and the interval is spilled,
1032 // it is not reloaded to a register.
1033 IntervalUseKind LinearScan::use_kind_of_output_operand(LIR_Op* op, LIR_Opr opr) {
1034 if (op->code() == lir_move) {
1035 assert(op->as_Op1() != NULL, "lir_move must be LIR_Op1");
1036 LIR_Op1* move = (LIR_Op1*)op;
1037 LIR_Opr res = move->result_opr();
1038 bool result_in_memory = res->is_virtual() && gen()->is_vreg_flag_set(res->vreg_number(), LIRGenerator::must_start_in_memory);
1039
1040 if (result_in_memory) {
1041 // Begin of an interval with must_start_in_memory set.
1042 // This interval will always get a stack slot first, so return noUse.
1043 return noUse;
1044
1045 } else if (move->in_opr()->is_stack()) {
1046 // method argument (condition must be equal to handle_method_arguments)
1047 return noUse;
1048
1049 } else if (move->in_opr()->is_register() && move->result_opr()->is_register()) {
1050 // Move from register to register
1051 if (block_of_op_with_id(op->id())->is_set(BlockBegin::osr_entry_flag)) {
1052 // special handling of phi-function moves inside osr-entry blocks
1053 // input operand must have a register instead of output operand (leads to better register allocation)
1054 return shouldHaveRegister;
1055 }
1056 }
1057 }
1058
1059 if (opr->is_virtual() &&
1060 gen()->is_vreg_flag_set(opr->vreg_number(), LIRGenerator::must_start_in_memory)) {
1061 // result is a stack-slot, so prevent immediate reloading
1062 return noUse;
1063 }
1064
1065 // all other operands require a register
1066 return mustHaveRegister;
1067 }
1068
1069 IntervalUseKind LinearScan::use_kind_of_input_operand(LIR_Op* op, LIR_Opr opr) {
1070 if (op->code() == lir_move) {
1071 assert(op->as_Op1() != NULL, "lir_move must be LIR_Op1");
1072 LIR_Op1* move = (LIR_Op1*)op;
1073 LIR_Opr res = move->result_opr();
1074 bool result_in_memory = res->is_virtual() && gen()->is_vreg_flag_set(res->vreg_number(), LIRGenerator::must_start_in_memory);
1075
1076 if (result_in_memory) {
1077 // Move to an interval with must_start_in_memory set.
1078 // To avoid moves from stack to stack (not allowed) force the input operand to a register
1079 return mustHaveRegister;
1080
1081 } else if (move->in_opr()->is_register() && move->result_opr()->is_register()) {
1082 // Move from register to register
1083 if (block_of_op_with_id(op->id())->is_set(BlockBegin::osr_entry_flag)) {
1084 // special handling of phi-function moves inside osr-entry blocks
1085 // input operand must have a register instead of output operand (leads to better register allocation)
1086 return mustHaveRegister;
1087 }
1088
1089 // The input operand is not forced to a register (moves from stack to register are allowed),
1090 // but it is faster if the input operand is in a register
1091 return shouldHaveRegister;
1092 }
1093 }
1094
1095
1096 #ifdef X86
1097 if (op->code() == lir_cmove) {
1098 // conditional moves can handle stack operands
1099 assert(op->result_opr()->is_register(), "result must always be in a register");
1100 return shouldHaveRegister;
1101 }
1102
1103 // optimizations for second input operand of arithmehtic operations on Intel
1104 // this operand is allowed to be on the stack in some cases
1105 BasicType opr_type = opr->type_register();
1106 if (opr_type == T_FLOAT || opr_type == T_DOUBLE) {
1107 if ((UseSSE == 1 && opr_type == T_FLOAT) || UseSSE >= 2) {
1108 // SSE float instruction (T_DOUBLE only supported with SSE2)
1109 switch (op->code()) {
1110 case lir_cmp:
1111 case lir_add:
1112 case lir_sub:
1113 case lir_mul:
1114 case lir_div:
1115 {
1116 assert(op->as_Op2() != NULL, "must be LIR_Op2");
1117 LIR_Op2* op2 = (LIR_Op2*)op;
1118 if (op2->in_opr1() != op2->in_opr2() && op2->in_opr2() == opr) {
1119 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");
1120 return shouldHaveRegister;
1121 }
1122 }
1123 }
1124 } else {
1125 // FPU stack float instruction
1126 switch (op->code()) {
1127 case lir_add:
1128 case lir_sub:
1129 case lir_mul:
1130 case lir_div:
1131 {
1132 assert(op->as_Op2() != NULL, "must be LIR_Op2");
1133 LIR_Op2* op2 = (LIR_Op2*)op;
1134 if (op2->in_opr1() != op2->in_opr2() && op2->in_opr2() == opr) {
1135 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");
1136 return shouldHaveRegister;
1137 }
1138 }
1139 }
1140 }
1141
1142 } else if (opr_type != T_LONG) {
1143 // integer instruction (note: long operands must always be in register)
1144 switch (op->code()) {
1145 case lir_cmp:
1146 case lir_add:
1147 case lir_sub:
1148 case lir_logic_and:
1149 case lir_logic_or:
1150 case lir_logic_xor:
1151 {
1152 assert(op->as_Op2() != NULL, "must be LIR_Op2");
1153 LIR_Op2* op2 = (LIR_Op2*)op;
1154 if (op2->in_opr1() != op2->in_opr2() && op2->in_opr2() == opr) {
1155 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");
1156 return shouldHaveRegister;
1157 }
1158 }
1159 }
1160 }
1161 #endif // X86
1162
1163 // all other operands require a register
1164 return mustHaveRegister;
1165 }
1166
1167
1168 void LinearScan::handle_method_arguments(LIR_Op* op) {
1169 // special handling for method arguments (moves from stack to virtual register):
1170 // the interval gets no register assigned, but the stack slot.
1171 // it is split before the first use by the register allocator.
1172
1173 if (op->code() == lir_move) {
1174 assert(op->as_Op1() != NULL, "must be LIR_Op1");
1175 LIR_Op1* move = (LIR_Op1*)op;
1176
1177 if (move->in_opr()->is_stack()) {
1178 #ifdef ASSERT
1179 int arg_size = compilation()->method()->arg_size();
1180 LIR_Opr o = move->in_opr();
1181 if (o->is_single_stack()) {
1182 assert(o->single_stack_ix() >= 0 && o->single_stack_ix() < arg_size, "out of range");
1183 } else if (o->is_double_stack()) {
1184 assert(o->double_stack_ix() >= 0 && o->double_stack_ix() < arg_size, "out of range");
1185 } else {
1186 ShouldNotReachHere();
1187 }
1188
1189 assert(move->id() > 0, "invalid id");
1190 assert(block_of_op_with_id(move->id())->number_of_preds() == 0, "move from stack must be in first block");
1191 assert(move->result_opr()->is_virtual(), "result of move must be a virtual register");
1192
1193 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())));
1194 #endif
1195
1196 Interval* interval = interval_at(reg_num(move->result_opr()));
1197
1198 int stack_slot = LinearScan::nof_regs + (move->in_opr()->is_single_stack() ? move->in_opr()->single_stack_ix() : move->in_opr()->double_stack_ix());
1199 interval->set_canonical_spill_slot(stack_slot);
1200 interval->assign_reg(stack_slot);
1201 }
1202 }
1203 }
1204
1205 void LinearScan::handle_doubleword_moves(LIR_Op* op) {
1206 // special handling for doubleword move from memory to register:
1207 // in this case the registers of the input address and the result
1208 // registers must not overlap -> add a temp range for the input registers
1209 if (op->code() == lir_move) {
1210 assert(op->as_Op1() != NULL, "must be LIR_Op1");
1211 LIR_Op1* move = (LIR_Op1*)op;
1212
1213 if (move->result_opr()->is_double_cpu() && move->in_opr()->is_pointer()) {
1214 LIR_Address* address = move->in_opr()->as_address_ptr();
1215 if (address != NULL) {
1216 if (address->base()->is_valid()) {
1217 add_temp(address->base(), op->id(), noUse);
1218 }
1219 if (address->index()->is_valid()) {
1220 add_temp(address->index(), op->id(), noUse);
1221 }
1222 }
1223 }
1224 }
1225 }
1226
1227 void LinearScan::add_register_hints(LIR_Op* op) {
1228 switch (op->code()) {
1229 case lir_move: // fall through
1230 case lir_convert: {
1231 assert(op->as_Op1() != NULL, "lir_move, lir_convert must be LIR_Op1");
1232 LIR_Op1* move = (LIR_Op1*)op;
1233
1234 LIR_Opr move_from = move->in_opr();
1235 LIR_Opr move_to = move->result_opr();
1236
1237 if (move_to->is_register() && move_from->is_register()) {
1238 Interval* from = interval_at(reg_num(move_from));
1239 Interval* to = interval_at(reg_num(move_to));
1240 if (from != NULL && to != NULL) {
1241 to->set_register_hint(from);
1242 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()));
1243 }
1244 }
1245 break;
1246 }
1247 case lir_cmove: {
1248 assert(op->as_Op2() != NULL, "lir_cmove must be LIR_Op2");
1249 LIR_Op2* cmove = (LIR_Op2*)op;
1250
1251 LIR_Opr move_from = cmove->in_opr1();
1252 LIR_Opr move_to = cmove->result_opr();
1253
1254 if (move_to->is_register() && move_from->is_register()) {
1255 Interval* from = interval_at(reg_num(move_from));
1256 Interval* to = interval_at(reg_num(move_to));
1257 if (from != NULL && to != NULL) {
1258 to->set_register_hint(from);
1259 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()));
1260 }
1261 }
1262 break;
1263 }
1264 }
1265 }
1266
1267
1268 void LinearScan::build_intervals() {
1269 TIME_LINEAR_SCAN(timer_build_intervals);
1270
1271 // initialize interval list with expected number of intervals
1272 // (32 is added to have some space for split children without having to resize the list)
1273 _intervals = IntervalList(num_virtual_regs() + 32);
1274 // initialize all slots that are used by build_intervals
1275 _intervals.at_put_grow(num_virtual_regs() - 1, NULL, NULL);
1276
1277 // create a list with all caller-save registers (cpu, fpu, xmm)
1278 // when an instruction is a call, a temp range is created for all these registers
1279 int num_caller_save_registers = 0;
1280 int caller_save_registers[LinearScan::nof_regs];
1281
1282 int i;
1283 for (i = 0; i < FrameMap::nof_caller_save_cpu_regs(); i++) {
1284 LIR_Opr opr = FrameMap::caller_save_cpu_reg_at(i);
1285 assert(opr->is_valid() && opr->is_register(), "FrameMap should not return invalid operands");
1286 assert(reg_numHi(opr) == -1, "missing addition of range for hi-register");
1287 caller_save_registers[num_caller_save_registers++] = reg_num(opr);
1288 }
1289
1290 // temp ranges for fpu registers are only created when the method has
1291 // virtual fpu operands. Otherwise no allocation for fpu registers is
1292 // perfomed and so the temp ranges would be useless
1293 if (has_fpu_registers()) {
1294 #ifdef X86
1295 if (UseSSE < 2) {
1296 #endif
1297 for (i = 0; i < FrameMap::nof_caller_save_fpu_regs; i++) {
1298 LIR_Opr opr = FrameMap::caller_save_fpu_reg_at(i);
1299 assert(opr->is_valid() && opr->is_register(), "FrameMap should not return invalid operands");
1300 assert(reg_numHi(opr) == -1, "missing addition of range for hi-register");
1301 caller_save_registers[num_caller_save_registers++] = reg_num(opr);
1302 }
1303 #ifdef X86
1304 }
1305 if (UseSSE > 0) {
1306 for (i = 0; i < FrameMap::nof_caller_save_xmm_regs; i++) {
1307 LIR_Opr opr = FrameMap::caller_save_xmm_reg_at(i);
1308 assert(opr->is_valid() && opr->is_register(), "FrameMap should not return invalid operands");
1309 assert(reg_numHi(opr) == -1, "missing addition of range for hi-register");
1310 caller_save_registers[num_caller_save_registers++] = reg_num(opr);
1311 }
1312 }
1313 #endif
1314 }
1315 assert(num_caller_save_registers <= LinearScan::nof_regs, "out of bounds");
1316
1317
1318 LIR_OpVisitState visitor;
1319
1320 // iterate all blocks in reverse order
1321 for (i = block_count() - 1; i >= 0; i--) {
1322 BlockBegin* block = block_at(i);
1323 LIR_OpList* instructions = block->lir()->instructions_list();
1324 int block_from = block->first_lir_instruction_id();
1325 int block_to = block->last_lir_instruction_id();
1326
1327 assert(block_from == instructions->at(0)->id(), "must be");
1328 assert(block_to == instructions->at(instructions->length() - 1)->id(), "must be");
1329
1330 // Update intervals for registers live at the end of this block;
1331 BitMap live = block->live_out();
1332 int size = (int)live.size();
1333 for (int number = (int)live.get_next_one_offset(0, size); number < size; number = (int)live.get_next_one_offset(number + 1, size)) {
1334 assert(live.at(number), "should not stop here otherwise");
1335 assert(number >= LIR_OprDesc::vreg_base, "fixed intervals must not be live on block bounds");
1336 TRACE_LINEAR_SCAN(2, tty->print_cr("live in %d to %d", number, block_to + 2));
1337
1338 add_use(number, block_from, block_to + 2, noUse, T_ILLEGAL);
1339
1340 // add special use positions for loop-end blocks when the
1341 // interval is used anywhere inside this loop. It's possible
1342 // that the block was part of a non-natural loop, so it might
1343 // have an invalid loop index.
1344 if (block->is_set(BlockBegin::linear_scan_loop_end_flag) &&
1345 block->loop_index() != -1 &&
1346 is_interval_in_loop(number, block->loop_index())) {
1347 interval_at(number)->add_use_pos(block_to + 1, loopEndMarker);
1348 }
1349 }
1350
1351 // iterate all instructions of the block in reverse order.
1352 // skip the first instruction because it is always a label
1353 // definitions of intervals are processed before uses
1354 assert(visitor.no_operands(instructions->at(0)), "first operation must always be a label");
1355 for (int j = instructions->length() - 1; j >= 1; j--) {
1356 LIR_Op* op = instructions->at(j);
1357 int op_id = op->id();
1358
1359 // visit operation to collect all operands
1360 visitor.visit(op);
1361
1362 // add a temp range for each register if operation destroys caller-save registers
1363 if (visitor.has_call()) {
1364 for (int k = 0; k < num_caller_save_registers; k++) {
1365 add_temp(caller_save_registers[k], op_id, noUse, T_ILLEGAL);
1366 }
1367 TRACE_LINEAR_SCAN(4, tty->print_cr("operation destroys all caller-save registers"));
1368 }
1369
1370 // Add any platform dependent temps
1371 pd_add_temps(op);
1372
1373 // visit definitions (output and temp operands)
1374 int k, n;
1375 n = visitor.opr_count(LIR_OpVisitState::outputMode);
1376 for (k = 0; k < n; k++) {
1377 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::outputMode, k);
1378 assert(opr->is_register(), "visitor should only return register operands");
1379 add_def(opr, op_id, use_kind_of_output_operand(op, opr));
1380 }
1381
1382 n = visitor.opr_count(LIR_OpVisitState::tempMode);
1383 for (k = 0; k < n; k++) {
1384 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::tempMode, k);
1385 assert(opr->is_register(), "visitor should only return register operands");
1386 add_temp(opr, op_id, mustHaveRegister);
1387 }
1388
1389 // visit uses (input operands)
1390 n = visitor.opr_count(LIR_OpVisitState::inputMode);
1391 for (k = 0; k < n; k++) {
1392 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::inputMode, k);
1393 assert(opr->is_register(), "visitor should only return register operands");
1394 add_use(opr, block_from, op_id, use_kind_of_input_operand(op, opr));
1395 }
1396
1397 // Add uses of live locals from interpreter's point of view for proper
1398 // debug information generation
1399 // Treat these operands as temp values (if the life range is extended
1400 // to a call site, the value would be in a register at the call otherwise)
1401 n = visitor.info_count();
1402 for (k = 0; k < n; k++) {
1403 CodeEmitInfo* info = visitor.info_at(k);
1404 ValueStack* stack = info->stack();
1405 for_each_state_value(stack, value,
1406 add_use(value, block_from, op_id + 1, noUse);
1407 );
1408 }
1409
1410 // special steps for some instructions (especially moves)
1411 handle_method_arguments(op);
1412 handle_doubleword_moves(op);
1413 add_register_hints(op);
1414
1415 } // end of instruction iteration
1416 } // end of block iteration
1417
1418
1419 // add the range [0, 1[ to all fixed intervals
1420 // -> the register allocator need not handle unhandled fixed intervals
1421 for (int n = 0; n < LinearScan::nof_regs; n++) {
1422 Interval* interval = interval_at(n);
1423 if (interval != NULL) {
1424 interval->add_range(0, 1);
1425 }
1426 }
1427 }
1428
1429
1430 // ********** Phase 5: actual register allocation
1431
1432 int LinearScan::interval_cmp(Interval** a, Interval** b) {
1433 if (*a != NULL) {
1434 if (*b != NULL) {
1435 return (*a)->from() - (*b)->from();
1436 } else {
1437 return -1;
1438 }
1439 } else {
1440 if (*b != NULL) {
1441 return 1;
1442 } else {
1443 return 0;
1444 }
1445 }
1446 }
1447
1448 #ifndef PRODUCT
1449 bool LinearScan::is_sorted(IntervalArray* intervals) {
1450 int from = -1;
1451 int i, j;
1452 for (i = 0; i < intervals->length(); i ++) {
1453 Interval* it = intervals->at(i);
1454 if (it != NULL) {
1455 if (from > it->from()) {
1456 assert(false, "");
1457 return false;
1458 }
1459 from = it->from();
1460 }
1461 }
1462
1463 // check in both directions if sorted list and unsorted list contain same intervals
1464 for (i = 0; i < interval_count(); i++) {
1465 if (interval_at(i) != NULL) {
1466 int num_found = 0;
1467 for (j = 0; j < intervals->length(); j++) {
1468 if (interval_at(i) == intervals->at(j)) {
1469 num_found++;
1470 }
1471 }
1472 assert(num_found == 1, "lists do not contain same intervals");
1473 }
1474 }
1475 for (j = 0; j < intervals->length(); j++) {
1476 int num_found = 0;
1477 for (i = 0; i < interval_count(); i++) {
1478 if (interval_at(i) == intervals->at(j)) {
1479 num_found++;
1480 }
1481 }
1482 assert(num_found == 1, "lists do not contain same intervals");
1483 }
1484
1485 return true;
1486 }
1487 #endif
1488
1489 void LinearScan::add_to_list(Interval** first, Interval** prev, Interval* interval) {
1490 if (*prev != NULL) {
1491 (*prev)->set_next(interval);
1492 } else {
1493 *first = interval;
1494 }
1495 *prev = interval;
1496 }
1497
1498 void LinearScan::create_unhandled_lists(Interval** list1, Interval** list2, bool (is_list1)(const Interval* i), bool (is_list2)(const Interval* i)) {
1499 assert(is_sorted(_sorted_intervals), "interval list is not sorted");
1500
1501 *list1 = *list2 = Interval::end();
1502
1503 Interval* list1_prev = NULL;
1504 Interval* list2_prev = NULL;
1505 Interval* v;
1506
1507 const int n = _sorted_intervals->length();
1508 for (int i = 0; i < n; i++) {
1509 v = _sorted_intervals->at(i);
1510 if (v == NULL) continue;
1511
1512 if (is_list1(v)) {
1513 add_to_list(list1, &list1_prev, v);
1514 } else if (is_list2 == NULL || is_list2(v)) {
1515 add_to_list(list2, &list2_prev, v);
1516 }
1517 }
1518
1519 if (list1_prev != NULL) list1_prev->set_next(Interval::end());
1520 if (list2_prev != NULL) list2_prev->set_next(Interval::end());
1521
1522 assert(list1_prev == NULL || list1_prev->next() == Interval::end(), "linear list ends not with sentinel");
1523 assert(list2_prev == NULL || list2_prev->next() == Interval::end(), "linear list ends not with sentinel");
1524 }
1525
1526
1527 void LinearScan::sort_intervals_before_allocation() {
1528 TIME_LINEAR_SCAN(timer_sort_intervals_before);
1529
1530 if (_needs_full_resort) {
1531 // There is no known reason why this should occur but just in case...
1532 assert(false, "should never occur");
1533 // Re-sort existing interval list because an Interval::from() has changed
1534 _sorted_intervals->sort(interval_cmp);
1535 _needs_full_resort = false;
1536 }
1537
1538 IntervalList* unsorted_list = &_intervals;
1539 int unsorted_len = unsorted_list->length();
1540 int sorted_len = 0;
1541 int unsorted_idx;
1542 int sorted_idx = 0;
1543 int sorted_from_max = -1;
1544
1545 // calc number of items for sorted list (sorted list must not contain NULL values)
1546 for (unsorted_idx = 0; unsorted_idx < unsorted_len; unsorted_idx++) {
1547 if (unsorted_list->at(unsorted_idx) != NULL) {
1548 sorted_len++;
1549 }
1550 }
1551 IntervalArray* sorted_list = new IntervalArray(sorted_len);
1552
1553 // special sorting algorithm: the original interval-list is almost sorted,
1554 // only some intervals are swapped. So this is much faster than a complete QuickSort
1555 for (unsorted_idx = 0; unsorted_idx < unsorted_len; unsorted_idx++) {
1556 Interval* cur_interval = unsorted_list->at(unsorted_idx);
1557
1558 if (cur_interval != NULL) {
1559 int cur_from = cur_interval->from();
1560
1561 if (sorted_from_max <= cur_from) {
1562 sorted_list->at_put(sorted_idx++, cur_interval);
1563 sorted_from_max = cur_interval->from();
1564 } else {
1565 // the asumption that the intervals are already sorted failed,
1566 // so this interval must be sorted in manually
1567 int j;
1568 for (j = sorted_idx - 1; j >= 0 && cur_from < sorted_list->at(j)->from(); j--) {
1569 sorted_list->at_put(j + 1, sorted_list->at(j));
1570 }
1571 sorted_list->at_put(j + 1, cur_interval);
1572 sorted_idx++;
1573 }
1574 }
1575 }
1576 _sorted_intervals = sorted_list;
1577 assert(is_sorted(_sorted_intervals), "intervals unsorted");
1578 }
1579
1580 void LinearScan::sort_intervals_after_allocation() {
1581 TIME_LINEAR_SCAN(timer_sort_intervals_after);
1582
1583 if (_needs_full_resort) {
1584 // Re-sort existing interval list because an Interval::from() has changed
1585 _sorted_intervals->sort(interval_cmp);
1586 _needs_full_resort = false;
1587 }
1588
1589 IntervalArray* old_list = _sorted_intervals;
1590 IntervalList* new_list = _new_intervals_from_allocation;
1591 int old_len = old_list->length();
1592 int new_len = new_list->length();
1593
1594 if (new_len == 0) {
1595 // no intervals have been added during allocation, so sorted list is already up to date
1596 assert(is_sorted(_sorted_intervals), "intervals unsorted");
1597 return;
1598 }
1599
1600 // conventional sort-algorithm for new intervals
1601 new_list->sort(interval_cmp);
1602
1603 // merge old and new list (both already sorted) into one combined list
1604 IntervalArray* combined_list = new IntervalArray(old_len + new_len);
1605 int old_idx = 0;
1606 int new_idx = 0;
1607
1608 while (old_idx + new_idx < old_len + new_len) {
1609 if (new_idx >= new_len || (old_idx < old_len && old_list->at(old_idx)->from() <= new_list->at(new_idx)->from())) {
1610 combined_list->at_put(old_idx + new_idx, old_list->at(old_idx));
1611 old_idx++;
1612 } else {
1613 combined_list->at_put(old_idx + new_idx, new_list->at(new_idx));
1614 new_idx++;
1615 }
1616 }
1617
1618 _sorted_intervals = combined_list;
1619 assert(is_sorted(_sorted_intervals), "intervals unsorted");
1620 }
1621
1622
1623 void LinearScan::allocate_registers() {
1624 TIME_LINEAR_SCAN(timer_allocate_registers);
1625
1626 Interval* precolored_cpu_intervals, *not_precolored_cpu_intervals;
1627 Interval* precolored_fpu_intervals, *not_precolored_fpu_intervals;
1628
1629 create_unhandled_lists(&precolored_cpu_intervals, ¬_precolored_cpu_intervals, is_precolored_cpu_interval, is_virtual_cpu_interval);
1630 if (has_fpu_registers()) {
1631 create_unhandled_lists(&precolored_fpu_intervals, ¬_precolored_fpu_intervals, is_precolored_fpu_interval, is_virtual_fpu_interval);
1632 #ifdef ASSERT
1633 } else {
1634 // fpu register allocation is omitted because no virtual fpu registers are present
1635 // just check this again...
1636 create_unhandled_lists(&precolored_fpu_intervals, ¬_precolored_fpu_intervals, is_precolored_fpu_interval, is_virtual_fpu_interval);
1637 assert(not_precolored_fpu_intervals == Interval::end(), "missed an uncolored fpu interval");
1638 #endif
1639 }
1640
1641 // allocate cpu registers
1642 LinearScanWalker cpu_lsw(this, precolored_cpu_intervals, not_precolored_cpu_intervals);
1643 cpu_lsw.walk();
1644 cpu_lsw.finish_allocation();
1645
1646 if (has_fpu_registers()) {
1647 // allocate fpu registers
1648 LinearScanWalker fpu_lsw(this, precolored_fpu_intervals, not_precolored_fpu_intervals);
1649 fpu_lsw.walk();
1650 fpu_lsw.finish_allocation();
1651 }
1652 }
1653
1654
1655 // ********** Phase 6: resolve data flow
1656 // (insert moves at edges between blocks if intervals have been split)
1657
1658 // wrapper for Interval::split_child_at_op_id that performs a bailout in product mode
1659 // instead of returning NULL
1660 Interval* LinearScan::split_child_at_op_id(Interval* interval, int op_id, LIR_OpVisitState::OprMode mode) {
1661 Interval* result = interval->split_child_at_op_id(op_id, mode);
1662 if (result != NULL) {
1663 return result;
1664 }
1665
1666 assert(false, "must find an interval, but do a clean bailout in product mode");
1667 result = new Interval(LIR_OprDesc::vreg_base);
1668 result->assign_reg(0);
1669 result->set_type(T_INT);
1670 BAILOUT_("LinearScan: interval is NULL", result);
1671 }
1672
1673
1674 Interval* LinearScan::interval_at_block_begin(BlockBegin* block, int reg_num) {
1675 assert(LinearScan::nof_regs <= reg_num && reg_num < num_virtual_regs(), "register number out of bounds");
1676 assert(interval_at(reg_num) != NULL, "no interval found");
1677
1678 return split_child_at_op_id(interval_at(reg_num), block->first_lir_instruction_id(), LIR_OpVisitState::outputMode);
1679 }
1680
1681 Interval* LinearScan::interval_at_block_end(BlockBegin* block, int reg_num) {
1682 assert(LinearScan::nof_regs <= reg_num && reg_num < num_virtual_regs(), "register number out of bounds");
1683 assert(interval_at(reg_num) != NULL, "no interval found");
1684
1685 return split_child_at_op_id(interval_at(reg_num), block->last_lir_instruction_id() + 1, LIR_OpVisitState::outputMode);
1686 }
1687
1688 Interval* LinearScan::interval_at_op_id(int reg_num, int op_id) {
1689 assert(LinearScan::nof_regs <= reg_num && reg_num < num_virtual_regs(), "register number out of bounds");
1690 assert(interval_at(reg_num) != NULL, "no interval found");
1691
1692 return split_child_at_op_id(interval_at(reg_num), op_id, LIR_OpVisitState::inputMode);
1693 }
1694
1695
1696 void LinearScan::resolve_collect_mappings(BlockBegin* from_block, BlockBegin* to_block, MoveResolver &move_resolver) {
1697 DEBUG_ONLY(move_resolver.check_empty());
1698
1699 const int num_regs = num_virtual_regs();
1700 const int size = live_set_size();
1701 const BitMap live_at_edge = to_block->live_in();
1702
1703 // visit all registers where the live_at_edge bit is set
1704 for (int r = (int)live_at_edge.get_next_one_offset(0, size); r < size; r = (int)live_at_edge.get_next_one_offset(r + 1, size)) {
1705 assert(r < num_regs, "live information set for not exisiting interval");
1706 assert(from_block->live_out().at(r) && to_block->live_in().at(r), "interval not live at this edge");
1707
1708 Interval* from_interval = interval_at_block_end(from_block, r);
1709 Interval* to_interval = interval_at_block_begin(to_block, r);
1710
1711 if (from_interval != to_interval && (from_interval->assigned_reg() != to_interval->assigned_reg() || from_interval->assigned_regHi() != to_interval->assigned_regHi())) {
1712 // need to insert move instruction
1713 move_resolver.add_mapping(from_interval, to_interval);
1714 }
1715 }
1716 }
1717
1718
1719 void LinearScan::resolve_find_insert_pos(BlockBegin* from_block, BlockBegin* to_block, MoveResolver &move_resolver) {
1720 if (from_block->number_of_sux() <= 1) {
1721 TRACE_LINEAR_SCAN(4, tty->print_cr("inserting moves at end of from_block B%d", from_block->block_id()));
1722
1723 LIR_OpList* instructions = from_block->lir()->instructions_list();
1724 LIR_OpBranch* branch = instructions->last()->as_OpBranch();
1725 if (branch != NULL) {
1726 // insert moves before branch
1727 assert(branch->cond() == lir_cond_always, "block does not end with an unconditional jump");
1728 move_resolver.set_insert_position(from_block->lir(), instructions->length() - 2);
1729 } else {
1730 move_resolver.set_insert_position(from_block->lir(), instructions->length() - 1);
1731 }
1732
1733 } else {
1734 TRACE_LINEAR_SCAN(4, tty->print_cr("inserting moves at beginning of to_block B%d", to_block->block_id()));
1735 #ifdef ASSERT
1736 assert(from_block->lir()->instructions_list()->at(0)->as_OpLabel() != NULL, "block does not start with a label");
1737
1738 // because the number of predecessor edges matches the number of
1739 // successor edges, blocks which are reached by switch statements
1740 // may have be more than one predecessor but it will be guaranteed
1741 // that all predecessors will be the same.
1742 for (int i = 0; i < to_block->number_of_preds(); i++) {
1743 assert(from_block == to_block->pred_at(i), "all critical edges must be broken");
1744 }
1745 #endif
1746
1747 move_resolver.set_insert_position(to_block->lir(), 0);
1748 }
1749 }
1750
1751
1752 // insert necessary moves (spilling or reloading) at edges between blocks if interval has been split
1753 void LinearScan::resolve_data_flow() {
1754 TIME_LINEAR_SCAN(timer_resolve_data_flow);
1755
1756 int num_blocks = block_count();
1757 MoveResolver move_resolver(this);
1758 BitMap block_completed(num_blocks); block_completed.clear();
1759 BitMap already_resolved(num_blocks); already_resolved.clear();
1760
1761 int i;
1762 for (i = 0; i < num_blocks; i++) {
1763 BlockBegin* block = block_at(i);
1764
1765 // check if block has only one predecessor and only one successor
1766 if (block->number_of_preds() == 1 && block->number_of_sux() == 1 && block->number_of_exception_handlers() == 0) {
1767 LIR_OpList* instructions = block->lir()->instructions_list();
1768 assert(instructions->at(0)->code() == lir_label, "block must start with label");
1769 assert(instructions->last()->code() == lir_branch, "block with successors must end with branch");
1770 assert(instructions->last()->as_OpBranch()->cond() == lir_cond_always, "block with successor must end with unconditional branch");
1771
1772 // check if block is empty (only label and branch)
1773 if (instructions->length() == 2) {
1774 BlockBegin* pred = block->pred_at(0);
1775 BlockBegin* sux = block->sux_at(0);
1776
1777 // prevent optimization of two consecutive blocks
1778 if (!block_completed.at(pred->linear_scan_number()) && !block_completed.at(sux->linear_scan_number())) {
1779 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()));
1780 block_completed.set_bit(block->linear_scan_number());
1781
1782 // directly resolve between pred and sux (without looking at the empty block between)
1783 resolve_collect_mappings(pred, sux, move_resolver);
1784 if (move_resolver.has_mappings()) {
1785 move_resolver.set_insert_position(block->lir(), 0);
1786 move_resolver.resolve_and_append_moves();
1787 }
1788 }
1789 }
1790 }
1791 }
1792
1793
1794 for (i = 0; i < num_blocks; i++) {
1795 if (!block_completed.at(i)) {
1796 BlockBegin* from_block = block_at(i);
1797 already_resolved.set_from(block_completed);
1798
1799 int num_sux = from_block->number_of_sux();
1800 for (int s = 0; s < num_sux; s++) {
1801 BlockBegin* to_block = from_block->sux_at(s);
1802
1803 // check for duplicate edges between the same blocks (can happen with switch blocks)
1804 if (!already_resolved.at(to_block->linear_scan_number())) {
1805 TRACE_LINEAR_SCAN(3, tty->print_cr("**** processing edge between B%d and B%d", from_block->block_id(), to_block->block_id()));
1806 already_resolved.set_bit(to_block->linear_scan_number());
1807
1808 // collect all intervals that have been split between from_block and to_block
1809 resolve_collect_mappings(from_block, to_block, move_resolver);
1810 if (move_resolver.has_mappings()) {
1811 resolve_find_insert_pos(from_block, to_block, move_resolver);
1812 move_resolver.resolve_and_append_moves();
1813 }
1814 }
1815 }
1816 }
1817 }
1818 }
1819
1820
1821 void LinearScan::resolve_exception_entry(BlockBegin* block, int reg_num, MoveResolver &move_resolver) {
1822 if (interval_at(reg_num) == NULL) {
1823 // if a phi function is never used, no interval is created -> ignore this
1824 return;
1825 }
1826
1827 Interval* interval = interval_at_block_begin(block, reg_num);
1828 int reg = interval->assigned_reg();
1829 int regHi = interval->assigned_regHi();
1830
1831 if ((reg < nof_regs && interval->always_in_memory()) ||
1832 (use_fpu_stack_allocation() && reg >= pd_first_fpu_reg && reg <= pd_last_fpu_reg)) {
1833 // the interval is split to get a short range that is located on the stack
1834 // in the following two cases:
1835 // * the interval started in memory (e.g. method parameter), but is currently in a register
1836 // this is an optimization for exception handling that reduces the number of moves that
1837 // are necessary for resolving the states when an exception uses this exception handler
1838 // * the interval would be on the fpu stack at the begin of the exception handler
1839 // this is not allowed because of the complicated fpu stack handling on Intel
1840
1841 // range that will be spilled to memory
1842 int from_op_id = block->first_lir_instruction_id();
1843 int to_op_id = from_op_id + 1; // short live range of length 1
1844 assert(interval->from() <= from_op_id && interval->to() >= to_op_id,
1845 "no split allowed between exception entry and first instruction");
1846
1847 if (interval->from() != from_op_id) {
1848 // the part before from_op_id is unchanged
1849 interval = interval->split(from_op_id);
1850 interval->assign_reg(reg, regHi);
1851 append_interval(interval);
1852 } else {
1853 _needs_full_resort = true;
1854 }
1855 assert(interval->from() == from_op_id, "must be true now");
1856
1857 Interval* spilled_part = interval;
1858 if (interval->to() != to_op_id) {
1859 // the part after to_op_id is unchanged
1860 spilled_part = interval->split_from_start(to_op_id);
1861 append_interval(spilled_part);
1862 move_resolver.add_mapping(spilled_part, interval);
1863 }
1864 assign_spill_slot(spilled_part);
1865
1866 assert(spilled_part->from() == from_op_id && spilled_part->to() == to_op_id, "just checking");
1867 }
1868 }
1869
1870 void LinearScan::resolve_exception_entry(BlockBegin* block, MoveResolver &move_resolver) {
1871 assert(block->is_set(BlockBegin::exception_entry_flag), "should not call otherwise");
1872 DEBUG_ONLY(move_resolver.check_empty());
1873
1874 // visit all registers where the live_in bit is set
1875 int size = live_set_size();
1876 for (int r = (int)block->live_in().get_next_one_offset(0, size); r < size; r = (int)block->live_in().get_next_one_offset(r + 1, size)) {
1877 resolve_exception_entry(block, r, move_resolver);
1878 }
1879
1880 // the live_in bits are not set for phi functions of the xhandler entry, so iterate them separately
1881 for_each_phi_fun(block, phi,
1882 resolve_exception_entry(block, phi->operand()->vreg_number(), move_resolver)
1883 );
1884
1885 if (move_resolver.has_mappings()) {
1886 // insert moves after first instruction
1887 move_resolver.set_insert_position(block->lir(), 1);
1888 move_resolver.resolve_and_append_moves();
1889 }
1890 }
1891
1892
1893 void LinearScan::resolve_exception_edge(XHandler* handler, int throwing_op_id, int reg_num, Phi* phi, MoveResolver &move_resolver) {
1894 if (interval_at(reg_num) == NULL) {
1895 // if a phi function is never used, no interval is created -> ignore this
1896 return;
1897 }
1898
1899 // the computation of to_interval is equal to resolve_collect_mappings,
1900 // but from_interval is more complicated because of phi functions
1901 BlockBegin* to_block = handler->entry_block();
1902 Interval* to_interval = interval_at_block_begin(to_block, reg_num);
1903
1904 if (phi != NULL) {
1905 // phi function of the exception entry block
1906 // no moves are created for this phi function in the LIR_Generator, so the
1907 // interval at the throwing instruction must be searched using the operands
1908 // of the phi function
1909 Value from_value = phi->operand_at(handler->phi_operand());
1910
1911 // with phi functions it can happen that the same from_value is used in
1912 // multiple mappings, so notify move-resolver that this is allowed
1913 move_resolver.set_multiple_reads_allowed();
1914
1915 Constant* con = from_value->as_Constant();
1916 if (con != NULL && !con->is_pinned()) {
1917 // unpinned constants may have no register, so add mapping from constant to interval
1918 move_resolver.add_mapping(LIR_OprFact::value_type(con->type()), to_interval);
1919 } else {
1920 // search split child at the throwing op_id
1921 Interval* from_interval = interval_at_op_id(from_value->operand()->vreg_number(), throwing_op_id);
1922 move_resolver.add_mapping(from_interval, to_interval);
1923 }
1924
1925 } else {
1926 // no phi function, so use reg_num also for from_interval
1927 // search split child at the throwing op_id
1928 Interval* from_interval = interval_at_op_id(reg_num, throwing_op_id);
1929 if (from_interval != to_interval) {
1930 // optimization to reduce number of moves: when to_interval is on stack and
1931 // the stack slot is known to be always correct, then no move is necessary
1932 if (!from_interval->always_in_memory() || from_interval->canonical_spill_slot() != to_interval->assigned_reg()) {
1933 move_resolver.add_mapping(from_interval, to_interval);
1934 }
1935 }
1936 }
1937 }
1938
1939 void LinearScan::resolve_exception_edge(XHandler* handler, int throwing_op_id, MoveResolver &move_resolver) {
1940 TRACE_LINEAR_SCAN(4, tty->print_cr("resolving exception handler B%d: throwing_op_id=%d", handler->entry_block()->block_id(), throwing_op_id));
1941
1942 DEBUG_ONLY(move_resolver.check_empty());
1943 assert(handler->lir_op_id() == -1, "already processed this xhandler");
1944 DEBUG_ONLY(handler->set_lir_op_id(throwing_op_id));
1945 assert(handler->entry_code() == NULL, "code already present");
1946
1947 // visit all registers where the live_in bit is set
1948 BlockBegin* block = handler->entry_block();
1949 int size = live_set_size();
1950 for (int r = (int)block->live_in().get_next_one_offset(0, size); r < size; r = (int)block->live_in().get_next_one_offset(r + 1, size)) {
1951 resolve_exception_edge(handler, throwing_op_id, r, NULL, move_resolver);
1952 }
1953
1954 // the live_in bits are not set for phi functions of the xhandler entry, so iterate them separately
1955 for_each_phi_fun(block, phi,
1956 resolve_exception_edge(handler, throwing_op_id, phi->operand()->vreg_number(), phi, move_resolver)
1957 );
1958
1959 if (move_resolver.has_mappings()) {
1960 LIR_List* entry_code = new LIR_List(compilation());
1961 move_resolver.set_insert_position(entry_code, 0);
1962 move_resolver.resolve_and_append_moves();
1963
1964 entry_code->jump(handler->entry_block());
1965 handler->set_entry_code(entry_code);
1966 }
1967 }
1968
1969
1970 void LinearScan::resolve_exception_handlers() {
1971 MoveResolver move_resolver(this);
1972 LIR_OpVisitState visitor;
1973 int num_blocks = block_count();
1974
1975 int i;
1976 for (i = 0; i < num_blocks; i++) {
1977 BlockBegin* block = block_at(i);
1978 if (block->is_set(BlockBegin::exception_entry_flag)) {
1979 resolve_exception_entry(block, move_resolver);
1980 }
1981 }
1982
1983 for (i = 0; i < num_blocks; i++) {
1984 BlockBegin* block = block_at(i);
1985 LIR_List* ops = block->lir();
1986 int num_ops = ops->length();
1987
1988 // iterate all instructions of the block. skip the first because it is always a label
1989 assert(visitor.no_operands(ops->at(0)), "first operation must always be a label");
1990 for (int j = 1; j < num_ops; j++) {
1991 LIR_Op* op = ops->at(j);
1992 int op_id = op->id();
1993
1994 if (op_id != -1 && has_info(op_id)) {
1995 // visit operation to collect all operands
1996 visitor.visit(op);
1997 assert(visitor.info_count() > 0, "should not visit otherwise");
1998
1999 XHandlers* xhandlers = visitor.all_xhandler();
2000 int n = xhandlers->length();
2001 for (int k = 0; k < n; k++) {
2002 resolve_exception_edge(xhandlers->handler_at(k), op_id, move_resolver);
2003 }
2004
2005 #ifdef ASSERT
2006 } else {
2007 visitor.visit(op);
2008 assert(visitor.all_xhandler()->length() == 0, "missed exception handler");
2009 #endif
2010 }
2011 }
2012 }
2013 }
2014
2015
2016 // ********** Phase 7: assign register numbers back to LIR
2017 // (includes computation of debug information and oop maps)
2018
2019 VMReg LinearScan::vm_reg_for_interval(Interval* interval) {
2020 VMReg reg = interval->cached_vm_reg();
2021 if (!reg->is_valid() ) {
2022 reg = vm_reg_for_operand(operand_for_interval(interval));
2023 interval->set_cached_vm_reg(reg);
2024 }
2025 assert(reg == vm_reg_for_operand(operand_for_interval(interval)), "wrong cached value");
2026 return reg;
2027 }
2028
2029 VMReg LinearScan::vm_reg_for_operand(LIR_Opr opr) {
2030 assert(opr->is_oop(), "currently only implemented for oop operands");
2031 return frame_map()->regname(opr);
2032 }
2033
2034
2035 LIR_Opr LinearScan::operand_for_interval(Interval* interval) {
2036 LIR_Opr opr = interval->cached_opr();
2037 if (opr->is_illegal()) {
2038 opr = calc_operand_for_interval(interval);
2039 interval->set_cached_opr(opr);
2040 }
2041
2042 assert(opr == calc_operand_for_interval(interval), "wrong cached value");
2043 return opr;
2044 }
2045
2046 LIR_Opr LinearScan::calc_operand_for_interval(const Interval* interval) {
2047 int assigned_reg = interval->assigned_reg();
2048 BasicType type = interval->type();
2049
2050 if (assigned_reg >= nof_regs) {
2051 // stack slot
2052 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2053 return LIR_OprFact::stack(assigned_reg - nof_regs, type);
2054
2055 } else {
2056 // register
2057 switch (type) {
2058 case T_OBJECT: {
2059 assert(assigned_reg >= pd_first_cpu_reg && assigned_reg <= pd_last_cpu_reg, "no cpu register");
2060 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2061 return LIR_OprFact::single_cpu_oop(assigned_reg);
2062 }
2063
2064 case T_ADDRESS: {
2065 assert(assigned_reg >= pd_first_cpu_reg && assigned_reg <= pd_last_cpu_reg, "no cpu register");
2066 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2067 return LIR_OprFact::single_cpu_address(assigned_reg);
2068 }
2069
2070 #ifdef __SOFTFP__
2071 case T_FLOAT: // fall through
2072 #endif // __SOFTFP__
2073 case T_INT: {
2074 assert(assigned_reg >= pd_first_cpu_reg && assigned_reg <= pd_last_cpu_reg, "no cpu register");
2075 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2076 return LIR_OprFact::single_cpu(assigned_reg);
2077 }
2078
2079 #ifdef __SOFTFP__
2080 case T_DOUBLE: // fall through
2081 #endif // __SOFTFP__
2082 case T_LONG: {
2083 int assigned_regHi = interval->assigned_regHi();
2084 assert(assigned_reg >= pd_first_cpu_reg && assigned_reg <= pd_last_cpu_reg, "no cpu register");
2085 assert(num_physical_regs(T_LONG) == 1 ||
2086 (assigned_regHi >= pd_first_cpu_reg && assigned_regHi <= pd_last_cpu_reg), "no cpu register");
2087
2088 assert(assigned_reg != assigned_regHi, "invalid allocation");
2089 assert(num_physical_regs(T_LONG) == 1 || assigned_reg < assigned_regHi,
2090 "register numbers must be sorted (ensure that e.g. a move from eax,ebx to ebx,eax can not occur)");
2091 assert((assigned_regHi != any_reg) ^ (num_physical_regs(T_LONG) == 1), "must be match");
2092 if (requires_adjacent_regs(T_LONG)) {
2093 assert(assigned_reg % 2 == 0 && assigned_reg + 1 == assigned_regHi, "must be sequential and even");
2094 }
2095
2096 #ifdef _LP64
2097 return LIR_OprFact::double_cpu(assigned_reg, assigned_reg);
2098 #else
2099 #if defined(SPARC) || defined(PPC)
2100 return LIR_OprFact::double_cpu(assigned_regHi, assigned_reg);
2101 #else
2102 return LIR_OprFact::double_cpu(assigned_reg, assigned_regHi);
2103 #endif // SPARC
2104 #endif // LP64
2105 }
2106
2107 #ifndef __SOFTFP__
2108 case T_FLOAT: {
2109 #ifdef X86
2110 if (UseSSE >= 1) {
2111 assert(assigned_reg >= pd_first_xmm_reg && assigned_reg <= pd_last_xmm_reg, "no xmm register");
2112 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2113 return LIR_OprFact::single_xmm(assigned_reg - pd_first_xmm_reg);
2114 }
2115 #endif
2116
2117 assert(assigned_reg >= pd_first_fpu_reg && assigned_reg <= pd_last_fpu_reg, "no fpu register");
2118 assert(interval->assigned_regHi() == any_reg, "must not have hi register");
2119 return LIR_OprFact::single_fpu(assigned_reg - pd_first_fpu_reg);
2120 }
2121
2122 case T_DOUBLE: {
2123 #ifdef X86
2124 if (UseSSE >= 2) {
2125 assert(assigned_reg >= pd_first_xmm_reg && assigned_reg <= pd_last_xmm_reg, "no xmm register");
2126 assert(interval->assigned_regHi() == any_reg, "must not have hi register (double xmm values are stored in one register)");
2127 return LIR_OprFact::double_xmm(assigned_reg - pd_first_xmm_reg);
2128 }
2129 #endif
2130
2131 #ifdef SPARC
2132 assert(assigned_reg >= pd_first_fpu_reg && assigned_reg <= pd_last_fpu_reg, "no fpu register");
2133 assert(interval->assigned_regHi() >= pd_first_fpu_reg && interval->assigned_regHi() <= pd_last_fpu_reg, "no fpu register");
2134 assert(assigned_reg % 2 == 0 && assigned_reg + 1 == interval->assigned_regHi(), "must be sequential and even");
2135 LIR_Opr result = LIR_OprFact::double_fpu(interval->assigned_regHi() - pd_first_fpu_reg, assigned_reg - pd_first_fpu_reg);
2136 #elif defined(ARM)
2137 assert(assigned_reg >= pd_first_fpu_reg && assigned_reg <= pd_last_fpu_reg, "no fpu register");
2138 assert(interval->assigned_regHi() >= pd_first_fpu_reg && interval->assigned_regHi() <= pd_last_fpu_reg, "no fpu register");
2139 assert(assigned_reg % 2 == 0 && assigned_reg + 1 == interval->assigned_regHi(), "must be sequential and even");
2140 LIR_Opr result = LIR_OprFact::double_fpu(assigned_reg - pd_first_fpu_reg, interval->assigned_regHi() - pd_first_fpu_reg);
2141 #else
2142 assert(assigned_reg >= pd_first_fpu_reg && assigned_reg <= pd_last_fpu_reg, "no fpu register");
2143 assert(interval->assigned_regHi() == any_reg, "must not have hi register (double fpu values are stored in one register on Intel)");
2144 LIR_Opr result = LIR_OprFact::double_fpu(assigned_reg - pd_first_fpu_reg);
2145 #endif
2146 return result;
2147 }
2148 #endif // __SOFTFP__
2149
2150 default: {
2151 ShouldNotReachHere();
2152 return LIR_OprFact::illegalOpr;
2153 }
2154 }
2155 }
2156 }
2157
2158 LIR_Opr LinearScan::canonical_spill_opr(Interval* interval) {
2159 assert(interval->canonical_spill_slot() >= nof_regs, "canonical spill slot not set");
2160 return LIR_OprFact::stack(interval->canonical_spill_slot() - nof_regs, interval->type());
2161 }
2162
2163 LIR_Opr LinearScan::color_lir_opr(LIR_Opr opr, int op_id, LIR_OpVisitState::OprMode mode) {
2164 assert(opr->is_virtual(), "should not call this otherwise");
2165
2166 Interval* interval = interval_at(opr->vreg_number());
2167 assert(interval != NULL, "interval must exist");
2168
2169 if (op_id != -1) {
2170 #ifdef ASSERT
2171 BlockBegin* block = block_of_op_with_id(op_id);
2172 if (block->number_of_sux() <= 1 && op_id == block->last_lir_instruction_id()) {
2173 // check if spill moves could have been appended at the end of this block, but
2174 // before the branch instruction. So the split child information for this branch would
2175 // be incorrect.
2176 LIR_OpBranch* branch = block->lir()->instructions_list()->last()->as_OpBranch();
2177 if (branch != NULL) {
2178 if (block->live_out().at(opr->vreg_number())) {
2179 assert(branch->cond() == lir_cond_always, "block does not end with an unconditional jump");
2180 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)");
2181 }
2182 }
2183 }
2184 #endif
2185
2186 // operands are not changed when an interval is split during allocation,
2187 // so search the right interval here
2188 interval = split_child_at_op_id(interval, op_id, mode);
2189 }
2190
2191 LIR_Opr res = operand_for_interval(interval);
2192
2193 #ifdef X86
2194 // new semantic for is_last_use: not only set on definite end of interval,
2195 // but also before hole
2196 // This may still miss some cases (e.g. for dead values), but it is not necessary that the
2197 // last use information is completely correct
2198 // information is only needed for fpu stack allocation
2199 if (res->is_fpu_register()) {
2200 if (opr->is_last_use() || op_id == interval->to() || (op_id != -1 && interval->has_hole_between(op_id, op_id + 1))) {
2201 assert(op_id == -1 || !is_block_begin(op_id), "holes at begin of block may also result from control flow");
2202 res = res->make_last_use();
2203 }
2204 }
2205 #endif
2206
2207 assert(!gen()->is_vreg_flag_set(opr->vreg_number(), LIRGenerator::callee_saved) || !FrameMap::is_caller_save_register(res), "bad allocation");
2208
2209 return res;
2210 }
2211
2212
2213 #ifdef ASSERT
2214 // some methods used to check correctness of debug information
2215
2216 void assert_no_register_values(GrowableArray<ScopeValue*>* values) {
2217 if (values == NULL) {
2218 return;
2219 }
2220
2221 for (int i = 0; i < values->length(); i++) {
2222 ScopeValue* value = values->at(i);
2223
2224 if (value->is_location()) {
2225 Location location = ((LocationValue*)value)->location();
2226 assert(location.where() == Location::on_stack, "value is in register");
2227 }
2228 }
2229 }
2230
2231 void assert_no_register_values(GrowableArray<MonitorValue*>* values) {
2232 if (values == NULL) {
2233 return;
2234 }
2235
2236 for (int i = 0; i < values->length(); i++) {
2237 MonitorValue* value = values->at(i);
2238
2239 if (value->owner()->is_location()) {
2240 Location location = ((LocationValue*)value->owner())->location();
2241 assert(location.where() == Location::on_stack, "owner is in register");
2242 }
2243 assert(value->basic_lock().where() == Location::on_stack, "basic_lock is in register");
2244 }
2245 }
2246
2247 void assert_equal(Location l1, Location l2) {
2248 assert(l1.where() == l2.where() && l1.type() == l2.type() && l1.offset() == l2.offset(), "");
2249 }
2250
2251 void assert_equal(ScopeValue* v1, ScopeValue* v2) {
2252 if (v1->is_location()) {
2253 assert(v2->is_location(), "");
2254 assert_equal(((LocationValue*)v1)->location(), ((LocationValue*)v2)->location());
2255 } else if (v1->is_constant_int()) {
2256 assert(v2->is_constant_int(), "");
2257 assert(((ConstantIntValue*)v1)->value() == ((ConstantIntValue*)v2)->value(), "");
2258 } else if (v1->is_constant_double()) {
2259 assert(v2->is_constant_double(), "");
2260 assert(((ConstantDoubleValue*)v1)->value() == ((ConstantDoubleValue*)v2)->value(), "");
2261 } else if (v1->is_constant_long()) {
2262 assert(v2->is_constant_long(), "");
2263 assert(((ConstantLongValue*)v1)->value() == ((ConstantLongValue*)v2)->value(), "");
2264 } else if (v1->is_constant_oop()) {
2265 assert(v2->is_constant_oop(), "");
2266 assert(((ConstantOopWriteValue*)v1)->value() == ((ConstantOopWriteValue*)v2)->value(), "");
2267 } else {
2268 ShouldNotReachHere();
2269 }
2270 }
2271
2272 void assert_equal(MonitorValue* m1, MonitorValue* m2) {
2273 assert_equal(m1->owner(), m2->owner());
2274 assert_equal(m1->basic_lock(), m2->basic_lock());
2275 }
2276
2277 void assert_equal(IRScopeDebugInfo* d1, IRScopeDebugInfo* d2) {
2278 assert(d1->scope() == d2->scope(), "not equal");
2279 assert(d1->bci() == d2->bci(), "not equal");
2280
2281 if (d1->locals() != NULL) {
2282 assert(d1->locals() != NULL && d2->locals() != NULL, "not equal");
2283 assert(d1->locals()->length() == d2->locals()->length(), "not equal");
2284 for (int i = 0; i < d1->locals()->length(); i++) {
2285 assert_equal(d1->locals()->at(i), d2->locals()->at(i));
2286 }
2287 } else {
2288 assert(d1->locals() == NULL && d2->locals() == NULL, "not equal");
2289 }
2290
2291 if (d1->expressions() != NULL) {
2292 assert(d1->expressions() != NULL && d2->expressions() != NULL, "not equal");
2293 assert(d1->expressions()->length() == d2->expressions()->length(), "not equal");
2294 for (int i = 0; i < d1->expressions()->length(); i++) {
2295 assert_equal(d1->expressions()->at(i), d2->expressions()->at(i));
2296 }
2297 } else {
2298 assert(d1->expressions() == NULL && d2->expressions() == NULL, "not equal");
2299 }
2300
2301 if (d1->monitors() != NULL) {
2302 assert(d1->monitors() != NULL && d2->monitors() != NULL, "not equal");
2303 assert(d1->monitors()->length() == d2->monitors()->length(), "not equal");
2304 for (int i = 0; i < d1->monitors()->length(); i++) {
2305 assert_equal(d1->monitors()->at(i), d2->monitors()->at(i));
2306 }
2307 } else {
2308 assert(d1->monitors() == NULL && d2->monitors() == NULL, "not equal");
2309 }
2310
2311 if (d1->caller() != NULL) {
2312 assert(d1->caller() != NULL && d2->caller() != NULL, "not equal");
2313 assert_equal(d1->caller(), d2->caller());
2314 } else {
2315 assert(d1->caller() == NULL && d2->caller() == NULL, "not equal");
2316 }
2317 }
2318
2319 void check_stack_depth(CodeEmitInfo* info, int stack_end) {
2320 if (info->stack()->bci() != SynchronizationEntryBCI && !info->scope()->method()->is_native()) {
2321 Bytecodes::Code code = info->scope()->method()->java_code_at_bci(info->stack()->bci());
2322 switch (code) {
2323 case Bytecodes::_ifnull : // fall through
2324 case Bytecodes::_ifnonnull : // fall through
2325 case Bytecodes::_ifeq : // fall through
2326 case Bytecodes::_ifne : // fall through
2327 case Bytecodes::_iflt : // fall through
2328 case Bytecodes::_ifge : // fall through
2329 case Bytecodes::_ifgt : // fall through
2330 case Bytecodes::_ifle : // fall through
2331 case Bytecodes::_if_icmpeq : // fall through
2332 case Bytecodes::_if_icmpne : // fall through
2333 case Bytecodes::_if_icmplt : // fall through
2334 case Bytecodes::_if_icmpge : // fall through
2335 case Bytecodes::_if_icmpgt : // fall through
2336 case Bytecodes::_if_icmple : // fall through
2337 case Bytecodes::_if_acmpeq : // fall through
2338 case Bytecodes::_if_acmpne :
2339 assert(stack_end >= -Bytecodes::depth(code), "must have non-empty expression stack at if bytecode");
2340 break;
2341 }
2342 }
2343 }
2344
2345 #endif // ASSERT
2346
2347
2348 IntervalWalker* LinearScan::init_compute_oop_maps() {
2349 // setup lists of potential oops for walking
2350 Interval* oop_intervals;
2351 Interval* non_oop_intervals;
2352
2353 create_unhandled_lists(&oop_intervals, &non_oop_intervals, is_oop_interval, NULL);
2354
2355 // intervals that have no oops inside need not to be processed
2356 // to ensure a walking until the last instruction id, add a dummy interval
2357 // with a high operation id
2358 non_oop_intervals = new Interval(any_reg);
2359 non_oop_intervals->add_range(max_jint - 2, max_jint - 1);
2360
2361 return new IntervalWalker(this, oop_intervals, non_oop_intervals);
2362 }
2363
2364
2365 OopMap* LinearScan::compute_oop_map(IntervalWalker* iw, LIR_Op* op, CodeEmitInfo* info, bool is_call_site) {
2366 TRACE_LINEAR_SCAN(3, tty->print_cr("creating oop map at op_id %d", op->id()));
2367
2368 // walk before the current operation -> intervals that start at
2369 // the operation (= output operands of the operation) are not
2370 // included in the oop map
2371 iw->walk_before(op->id());
2372
2373 int frame_size = frame_map()->framesize();
2374 int arg_count = frame_map()->oop_map_arg_count();
2375 OopMap* map = new OopMap(frame_size, arg_count);
2376
2377 // Check if this is a patch site.
2378 bool is_patch_info = false;
2379 if (op->code() == lir_move) {
2380 assert(!is_call_site, "move must not be a call site");
2381 assert(op->as_Op1() != NULL, "move must be LIR_Op1");
2382 LIR_Op1* move = (LIR_Op1*)op;
2383
2384 is_patch_info = move->patch_code() != lir_patch_none;
2385 }
2386
2387 // Iterate through active intervals
2388 for (Interval* interval = iw->active_first(fixedKind); interval != Interval::end(); interval = interval->next()) {
2389 int assigned_reg = interval->assigned_reg();
2390
2391 assert(interval->current_from() <= op->id() && op->id() <= interval->current_to(), "interval should not be active otherwise");
2392 assert(interval->assigned_regHi() == any_reg, "oop must be single word");
2393 assert(interval->reg_num() >= LIR_OprDesc::vreg_base, "fixed interval found");
2394
2395 // Check if this range covers the instruction. Intervals that
2396 // start or end at the current operation are not included in the
2397 // oop map, except in the case of patching moves. For patching
2398 // moves, any intervals which end at this instruction are included
2399 // in the oop map since we may safepoint while doing the patch
2400 // before we've consumed the inputs.
2401 if (is_patch_info || op->id() < interval->current_to()) {
2402
2403 // caller-save registers must not be included into oop-maps at calls
2404 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");
2405
2406 VMReg name = vm_reg_for_interval(interval);
2407 set_oop(map, name);
2408
2409 // Spill optimization: when the stack value is guaranteed to be always correct,
2410 // then it must be added to the oop map even if the interval is currently in a register
2411 if (interval->always_in_memory() &&
2412 op->id() > interval->spill_definition_pos() &&
2413 interval->assigned_reg() != interval->canonical_spill_slot()) {
2414 assert(interval->spill_definition_pos() > 0, "position not set correctly");
2415 assert(interval->canonical_spill_slot() >= LinearScan::nof_regs, "no spill slot assigned");
2416 assert(interval->assigned_reg() < LinearScan::nof_regs, "interval is on stack, so stack slot is registered twice");
2417
2418 set_oop(map, frame_map()->slot_regname(interval->canonical_spill_slot() - LinearScan::nof_regs));
2419 }
2420 }
2421 }
2422
2423 // add oops from lock stack
2424 assert(info->stack() != NULL, "CodeEmitInfo must always have a stack");
2425 int locks_count = info->stack()->total_locks_size();
2426 for (int i = 0; i < locks_count; i++) {
2427 set_oop(map, frame_map()->monitor_object_regname(i));
2428 }
2429
2430 return map;
2431 }
2432
2433
2434 void LinearScan::compute_oop_map(IntervalWalker* iw, const LIR_OpVisitState &visitor, LIR_Op* op) {
2435 assert(visitor.info_count() > 0, "no oop map needed");
2436
2437 // compute oop_map only for first CodeEmitInfo
2438 // because it is (in most cases) equal for all other infos of the same operation
2439 CodeEmitInfo* first_info = visitor.info_at(0);
2440 OopMap* first_oop_map = compute_oop_map(iw, op, first_info, visitor.has_call());
2441
2442 for (int i = 0; i < visitor.info_count(); i++) {
2443 CodeEmitInfo* info = visitor.info_at(i);
2444 OopMap* oop_map = first_oop_map;
2445
2446 if (info->stack()->locks_size() != first_info->stack()->locks_size()) {
2447 // this info has a different number of locks then the precomputed oop map
2448 // (possible for lock and unlock instructions) -> compute oop map with
2449 // correct lock information
2450 oop_map = compute_oop_map(iw, op, info, visitor.has_call());
2451 }
2452
2453 if (info->_oop_map == NULL) {
2454 info->_oop_map = oop_map;
2455 } else {
2456 // a CodeEmitInfo can not be shared between different LIR-instructions
2457 // because interval splitting can occur anywhere between two instructions
2458 // and so the oop maps must be different
2459 // -> check if the already set oop_map is exactly the one calculated for this operation
2460 assert(info->_oop_map == oop_map, "same CodeEmitInfo used for multiple LIR instructions");
2461 }
2462 }
2463 }
2464
2465
2466 // frequently used constants
2467 // Allocate them with new so they are never destroyed (otherwise, a
2468 // forced exit could destroy these objects while they are still in
2469 // use).
2470 ConstantOopWriteValue* LinearScan::_oop_null_scope_value = new (ResourceObj::C_HEAP) ConstantOopWriteValue(NULL);
2471 ConstantIntValue* LinearScan::_int_m1_scope_value = new (ResourceObj::C_HEAP) ConstantIntValue(-1);
2472 ConstantIntValue* LinearScan::_int_0_scope_value = new (ResourceObj::C_HEAP) ConstantIntValue(0);
2473 ConstantIntValue* LinearScan::_int_1_scope_value = new (ResourceObj::C_HEAP) ConstantIntValue(1);
2474 ConstantIntValue* LinearScan::_int_2_scope_value = new (ResourceObj::C_HEAP) ConstantIntValue(2);
2475 LocationValue* _illegal_value = new (ResourceObj::C_HEAP) LocationValue(Location());
2476
2477 void LinearScan::init_compute_debug_info() {
2478 // cache for frequently used scope values
2479 // (cpu registers and stack slots)
2480 _scope_value_cache = ScopeValueArray((LinearScan::nof_cpu_regs + frame_map()->argcount() + max_spills()) * 2, NULL);
2481 }
2482
2483 MonitorValue* LinearScan::location_for_monitor_index(int monitor_index) {
2484 Location loc;
2485 if (!frame_map()->location_for_monitor_object(monitor_index, &loc)) {
2486 bailout("too large frame");
2487 }
2488 ScopeValue* object_scope_value = new LocationValue(loc);
2489
2490 if (!frame_map()->location_for_monitor_lock(monitor_index, &loc)) {
2491 bailout("too large frame");
2492 }
2493 return new MonitorValue(object_scope_value, loc);
2494 }
2495
2496 LocationValue* LinearScan::location_for_name(int name, Location::Type loc_type) {
2497 Location loc;
2498 if (!frame_map()->locations_for_slot(name, loc_type, &loc)) {
2499 bailout("too large frame");
2500 }
2501 return new LocationValue(loc);
2502 }
2503
2504
2505 int LinearScan::append_scope_value_for_constant(LIR_Opr opr, GrowableArray<ScopeValue*>* scope_values) {
2506 assert(opr->is_constant(), "should not be called otherwise");
2507
2508 LIR_Const* c = opr->as_constant_ptr();
2509 BasicType t = c->type();
2510 switch (t) {
2511 case T_OBJECT: {
2512 jobject value = c->as_jobject();
2513 if (value == NULL) {
2514 scope_values->append(_oop_null_scope_value);
2515 } else {
2516 scope_values->append(new ConstantOopWriteValue(c->as_jobject()));
2517 }
2518 return 1;
2519 }
2520
2521 case T_INT: // fall through
2522 case T_FLOAT: {
2523 int value = c->as_jint_bits();
2524 switch (value) {
2525 case -1: scope_values->append(_int_m1_scope_value); break;
2526 case 0: scope_values->append(_int_0_scope_value); break;
2527 case 1: scope_values->append(_int_1_scope_value); break;
2528 case 2: scope_values->append(_int_2_scope_value); break;
2529 default: scope_values->append(new ConstantIntValue(c->as_jint_bits())); break;
2530 }
2531 return 1;
2532 }
2533
2534 case T_LONG: // fall through
2535 case T_DOUBLE: {
2536 #ifdef _LP64
2537 scope_values->append(_int_0_scope_value);
2538 scope_values->append(new ConstantLongValue(c->as_jlong_bits()));
2539 #else
2540 if (hi_word_offset_in_bytes > lo_word_offset_in_bytes) {
2541 scope_values->append(new ConstantIntValue(c->as_jint_hi_bits()));
2542 scope_values->append(new ConstantIntValue(c->as_jint_lo_bits()));
2543 } else {
2544 scope_values->append(new ConstantIntValue(c->as_jint_lo_bits()));
2545 scope_values->append(new ConstantIntValue(c->as_jint_hi_bits()));
2546 }
2547 #endif
2548 return 2;
2549 }
2550
2551 case T_ADDRESS: {
2552 #ifdef _LP64
2553 scope_values->append(new ConstantLongValue(c->as_jint()));
2554 #else
2555 scope_values->append(new ConstantIntValue(c->as_jint()));
2556 #endif
2557 return 1;
2558 }
2559
2560 default:
2561 ShouldNotReachHere();
2562 return -1;
2563 }
2564 }
2565
2566 int LinearScan::append_scope_value_for_operand(LIR_Opr opr, GrowableArray<ScopeValue*>* scope_values) {
2567 if (opr->is_single_stack()) {
2568 int stack_idx = opr->single_stack_ix();
2569 bool is_oop = opr->is_oop_register();
2570 int cache_idx = (stack_idx + LinearScan::nof_cpu_regs) * 2 + (is_oop ? 1 : 0);
2571
2572 ScopeValue* sv = _scope_value_cache.at(cache_idx);
2573 if (sv == NULL) {
2574 Location::Type loc_type = is_oop ? Location::oop : Location::normal;
2575 sv = location_for_name(stack_idx, loc_type);
2576 _scope_value_cache.at_put(cache_idx, sv);
2577 }
2578
2579 // check if cached value is correct
2580 DEBUG_ONLY(assert_equal(sv, location_for_name(stack_idx, is_oop ? Location::oop : Location::normal)));
2581
2582 scope_values->append(sv);
2583 return 1;
2584
2585 } else if (opr->is_single_cpu()) {
2586 bool is_oop = opr->is_oop_register();
2587 int cache_idx = opr->cpu_regnr() * 2 + (is_oop ? 1 : 0);
2588 Location::Type int_loc_type = NOT_LP64(Location::normal) LP64_ONLY(Location::int_in_long);
2589
2590 ScopeValue* sv = _scope_value_cache.at(cache_idx);
2591 if (sv == NULL) {
2592 Location::Type loc_type = is_oop ? Location::oop : int_loc_type;
2593 VMReg rname = frame_map()->regname(opr);
2594 sv = new LocationValue(Location::new_reg_loc(loc_type, rname));
2595 _scope_value_cache.at_put(cache_idx, sv);
2596 }
2597
2598 // check if cached value is correct
2599 DEBUG_ONLY(assert_equal(sv, new LocationValue(Location::new_reg_loc(is_oop ? Location::oop : int_loc_type, frame_map()->regname(opr)))));
2600
2601 scope_values->append(sv);
2602 return 1;
2603
2604 #ifdef X86
2605 } else if (opr->is_single_xmm()) {
2606 VMReg rname = opr->as_xmm_float_reg()->as_VMReg();
2607 LocationValue* sv = new LocationValue(Location::new_reg_loc(Location::normal, rname));
2608
2609 scope_values->append(sv);
2610 return 1;
2611 #endif
2612
2613 } else if (opr->is_single_fpu()) {
2614 #ifdef X86
2615 // the exact location of fpu stack values is only known
2616 // during fpu stack allocation, so the stack allocator object
2617 // must be present
2618 assert(use_fpu_stack_allocation(), "should not have float stack values without fpu stack allocation (all floats must be SSE2)");
2619 assert(_fpu_stack_allocator != NULL, "must be present");
2620 opr = _fpu_stack_allocator->to_fpu_stack(opr);
2621 #endif
2622
2623 Location::Type loc_type = float_saved_as_double ? Location::float_in_dbl : Location::normal;
2624 VMReg rname = frame_map()->fpu_regname(opr->fpu_regnr());
2625 #ifndef __SOFTFP__
2626 #ifndef VM_LITTLE_ENDIAN
2627 if (! float_saved_as_double) {
2628 // On big endian system, we may have an issue if float registers use only
2629 // the low half of the (same) double registers.
2630 // Both the float and the double could have the same regnr but would correspond
2631 // to two different addresses once saved.
2632
2633 // get next safely (no assertion checks)
2634 VMReg next = VMRegImpl::as_VMReg(1+rname->value());
2635 if (next->is_reg() &&
2636 (next->as_FloatRegister() == rname->as_FloatRegister())) {
2637 // the back-end does use the same numbering for the double and the float
2638 rname = next; // VMReg for the low bits, e.g. the real VMReg for the float
2639 }
2640 }
2641 #endif
2642 #endif
2643 LocationValue* sv = new LocationValue(Location::new_reg_loc(loc_type, rname));
2644
2645 scope_values->append(sv);
2646 return 1;
2647
2648 } else {
2649 // double-size operands
2650
2651 ScopeValue* first;
2652 ScopeValue* second;
2653
2654 if (opr->is_double_stack()) {
2655 #ifdef _LP64
2656 Location loc1;
2657 Location::Type loc_type = opr->type() == T_LONG ? Location::lng : Location::dbl;
2658 if (!frame_map()->locations_for_slot(opr->double_stack_ix(), loc_type, &loc1, NULL)) {
2659 bailout("too large frame");
2660 }
2661 // Does this reverse on x86 vs. sparc?
2662 first = new LocationValue(loc1);
2663 second = _int_0_scope_value;
2664 #else
2665 Location loc1, loc2;
2666 if (!frame_map()->locations_for_slot(opr->double_stack_ix(), Location::normal, &loc1, &loc2)) {
2667 bailout("too large frame");
2668 }
2669 first = new LocationValue(loc1);
2670 second = new LocationValue(loc2);
2671 #endif // _LP64
2672
2673 } else if (opr->is_double_cpu()) {
2674 #ifdef _LP64
2675 VMReg rname_first = opr->as_register_lo()->as_VMReg();
2676 first = new LocationValue(Location::new_reg_loc(Location::lng, rname_first));
2677 second = _int_0_scope_value;
2678 #else
2679 VMReg rname_first = opr->as_register_lo()->as_VMReg();
2680 VMReg rname_second = opr->as_register_hi()->as_VMReg();
2681
2682 if (hi_word_offset_in_bytes < lo_word_offset_in_bytes) {
2683 // lo/hi and swapped relative to first and second, so swap them
2684 VMReg tmp = rname_first;
2685 rname_first = rname_second;
2686 rname_second = tmp;
2687 }
2688
2689 first = new LocationValue(Location::new_reg_loc(Location::normal, rname_first));
2690 second = new LocationValue(Location::new_reg_loc(Location::normal, rname_second));
2691 #endif //_LP64
2692
2693
2694 #ifdef X86
2695 } else if (opr->is_double_xmm()) {
2696 assert(opr->fpu_regnrLo() == opr->fpu_regnrHi(), "assumed in calculation");
2697 VMReg rname_first = opr->as_xmm_double_reg()->as_VMReg();
2698 # ifdef _LP64
2699 first = new LocationValue(Location::new_reg_loc(Location::dbl, rname_first));
2700 second = _int_0_scope_value;
2701 # else
2702 first = new LocationValue(Location::new_reg_loc(Location::normal, rname_first));
2703 // %%% This is probably a waste but we'll keep things as they were for now
2704 if (true) {
2705 VMReg rname_second = rname_first->next();
2706 second = new LocationValue(Location::new_reg_loc(Location::normal, rname_second));
2707 }
2708 # endif
2709 #endif
2710
2711 } else if (opr->is_double_fpu()) {
2712 // On SPARC, fpu_regnrLo/fpu_regnrHi represents the two halves of
2713 // the double as float registers in the native ordering. On X86,
2714 // fpu_regnrLo is a FPU stack slot whose VMReg represents
2715 // the low-order word of the double and fpu_regnrLo + 1 is the
2716 // name for the other half. *first and *second must represent the
2717 // least and most significant words, respectively.
2718
2719 #ifdef X86
2720 // the exact location of fpu stack values is only known
2721 // during fpu stack allocation, so the stack allocator object
2722 // must be present
2723 assert(use_fpu_stack_allocation(), "should not have float stack values without fpu stack allocation (all floats must be SSE2)");
2724 assert(_fpu_stack_allocator != NULL, "must be present");
2725 opr = _fpu_stack_allocator->to_fpu_stack(opr);
2726
2727 assert(opr->fpu_regnrLo() == opr->fpu_regnrHi(), "assumed in calculation (only fpu_regnrLo is used)");
2728 #endif
2729 #ifdef SPARC
2730 assert(opr->fpu_regnrLo() == opr->fpu_regnrHi() + 1, "assumed in calculation (only fpu_regnrHi is used)");
2731 #endif
2732 #ifdef ARM
2733 assert(opr->fpu_regnrHi() == opr->fpu_regnrLo() + 1, "assumed in calculation (only fpu_regnrLo is used)");
2734 #endif
2735 #ifdef PPC
2736 assert(opr->fpu_regnrLo() == opr->fpu_regnrHi(), "assumed in calculation (only fpu_regnrHi is used)");
2737 #endif
2738
2739 #ifdef VM_LITTLE_ENDIAN
2740 VMReg rname_first = frame_map()->fpu_regname(opr->fpu_regnrLo());
2741 #else
2742 VMReg rname_first = frame_map()->fpu_regname(opr->fpu_regnrHi());
2743 #endif
2744
2745 #ifdef _LP64
2746 first = new LocationValue(Location::new_reg_loc(Location::dbl, rname_first));
2747 second = _int_0_scope_value;
2748 #else
2749 first = new LocationValue(Location::new_reg_loc(Location::normal, rname_first));
2750 // %%% This is probably a waste but we'll keep things as they were for now
2751 if (true) {
2752 VMReg rname_second = rname_first->next();
2753 second = new LocationValue(Location::new_reg_loc(Location::normal, rname_second));
2754 }
2755 #endif
2756
2757 } else {
2758 ShouldNotReachHere();
2759 first = NULL;
2760 second = NULL;
2761 }
2762
2763 assert(first != NULL && second != NULL, "must be set");
2764 // The convention the interpreter uses is that the second local
2765 // holds the first raw word of the native double representation.
2766 // This is actually reasonable, since locals and stack arrays
2767 // grow downwards in all implementations.
2768 // (If, on some machine, the interpreter's Java locals or stack
2769 // were to grow upwards, the embedded doubles would be word-swapped.)
2770 scope_values->append(second);
2771 scope_values->append(first);
2772 return 2;
2773 }
2774 }
2775
2776
2777 int LinearScan::append_scope_value(int op_id, Value value, GrowableArray<ScopeValue*>* scope_values) {
2778 if (value != NULL) {
2779 LIR_Opr opr = value->operand();
2780 Constant* con = value->as_Constant();
2781
2782 assert(con == NULL || opr->is_virtual() || opr->is_constant() || opr->is_illegal(), "asumption: Constant instructions have only constant operands (or illegal if constant is optimized away)");
2783 assert(con != NULL || opr->is_virtual(), "asumption: non-Constant instructions have only virtual operands");
2784
2785 if (con != NULL && !con->is_pinned() && !opr->is_constant()) {
2786 // Unpinned constants may have a virtual operand for a part of the lifetime
2787 // or may be illegal when it was optimized away,
2788 // so always use a constant operand
2789 opr = LIR_OprFact::value_type(con->type());
2790 }
2791 assert(opr->is_virtual() || opr->is_constant(), "other cases not allowed here");
2792
2793 if (opr->is_virtual()) {
2794 LIR_OpVisitState::OprMode mode = LIR_OpVisitState::inputMode;
2795
2796 BlockBegin* block = block_of_op_with_id(op_id);
2797 if (block->number_of_sux() == 1 && op_id == block->last_lir_instruction_id()) {
2798 // generating debug information for the last instruction of a block.
2799 // if this instruction is a branch, spill moves are inserted before this branch
2800 // and so the wrong operand would be returned (spill moves at block boundaries are not
2801 // considered in the live ranges of intervals)
2802 // Solution: use the first op_id of the branch target block instead.
2803 if (block->lir()->instructions_list()->last()->as_OpBranch() != NULL) {
2804 if (block->live_out().at(opr->vreg_number())) {
2805 op_id = block->sux_at(0)->first_lir_instruction_id();
2806 mode = LIR_OpVisitState::outputMode;
2807 }
2808 }
2809 }
2810
2811 // Get current location of operand
2812 // The operand must be live because debug information is considered when building the intervals
2813 // if the interval is not live, color_lir_opr will cause an assertion failure
2814 opr = color_lir_opr(opr, op_id, mode);
2815 assert(!has_call(op_id) || opr->is_stack() || !is_caller_save(reg_num(opr)), "can not have caller-save register operands at calls");
2816
2817 // Append to ScopeValue array
2818 return append_scope_value_for_operand(opr, scope_values);
2819
2820 } else {
2821 assert(value->as_Constant() != NULL, "all other instructions have only virtual operands");
2822 assert(opr->is_constant(), "operand must be constant");
2823
2824 return append_scope_value_for_constant(opr, scope_values);
2825 }
2826 } else {
2827 // append a dummy value because real value not needed
2828 scope_values->append(_illegal_value);
2829 return 1;
2830 }
2831 }
2832
2833
2834 IRScopeDebugInfo* LinearScan::compute_debug_info_for_scope(int op_id, IRScope* cur_scope, ValueStack* cur_state, ValueStack* innermost_state) {
2835 IRScopeDebugInfo* caller_debug_info = NULL;
2836
2837 ValueStack* caller_state = cur_state->caller_state();
2838 if (caller_state != NULL) {
2839 // process recursively to compute outermost scope first
2840 caller_debug_info = compute_debug_info_for_scope(op_id, cur_scope->caller(), caller_state, innermost_state);
2841 }
2842
2843 // initialize these to null.
2844 // If we don't need deopt info or there are no locals, expressions or monitors,
2845 // then these get recorded as no information and avoids the allocation of 0 length arrays.
2846 GrowableArray<ScopeValue*>* locals = NULL;
2847 GrowableArray<ScopeValue*>* expressions = NULL;
2848 GrowableArray<MonitorValue*>* monitors = NULL;
2849
2850 // describe local variable values
2851 int nof_locals = cur_state->locals_size();
2852 if (nof_locals > 0) {
2853 locals = new GrowableArray<ScopeValue*>(nof_locals);
2854
2855 int pos = 0;
2856 while (pos < nof_locals) {
2857 assert(pos < cur_state->locals_size(), "why not?");
2858
2859 Value local = cur_state->local_at(pos);
2860 pos += append_scope_value(op_id, local, locals);
2861
2862 assert(locals->length() == pos, "must match");
2863 }
2864 assert(locals->length() == cur_scope->method()->max_locals(), "wrong number of locals");
2865 assert(locals->length() == cur_state->locals_size(), "wrong number of locals");
2866 } else if (cur_scope->method()->max_locals() > 0) {
2867 assert(cur_state->kind() == ValueStack::EmptyExceptionState, "should be");
2868 nof_locals = cur_scope->method()->max_locals();
2869 locals = new GrowableArray<ScopeValue*>(nof_locals);
2870 for(int i = 0; i < nof_locals; i++) {
2871 locals->append(_illegal_value);
2872 }
2873 }
2874
2875 // describe expression stack
2876 int nof_stack = cur_state->stack_size();
2877 if (nof_stack > 0) {
2878 expressions = new GrowableArray<ScopeValue*>(nof_stack);
2879
2880 int pos = 0;
2881 while (pos < nof_stack) {
2882 Value expression = cur_state->stack_at_inc(pos);
2883 append_scope_value(op_id, expression, expressions);
2884
2885 assert(expressions->length() == pos, "must match");
2886 }
2887 assert(expressions->length() == cur_state->stack_size(), "wrong number of stack entries");
2888 }
2889
2890 // describe monitors
2891 int nof_locks = cur_state->locks_size();
2892 if (nof_locks > 0) {
2893 int lock_offset = cur_state->caller_state() != NULL ? cur_state->caller_state()->total_locks_size() : 0;
2894 monitors = new GrowableArray<MonitorValue*>(nof_locks);
2895 for (int i = 0; i < nof_locks; i++) {
2896 monitors->append(location_for_monitor_index(lock_offset + i));
2897 }
2898 }
2899
2900 return new IRScopeDebugInfo(cur_scope, cur_state->bci(), locals, expressions, monitors, caller_debug_info);
2901 }
2902
2903
2904 void LinearScan::compute_debug_info(CodeEmitInfo* info, int op_id) {
2905 TRACE_LINEAR_SCAN(3, tty->print_cr("creating debug information at op_id %d", op_id));
2906
2907 IRScope* innermost_scope = info->scope();
2908 ValueStack* innermost_state = info->stack();
2909
2910 assert(innermost_scope != NULL && innermost_state != NULL, "why is it missing?");
2911
2912 DEBUG_ONLY(check_stack_depth(info, innermost_state->stack_size()));
2913
2914 if (info->_scope_debug_info == NULL) {
2915 // compute debug information
2916 info->_scope_debug_info = compute_debug_info_for_scope(op_id, innermost_scope, innermost_state, innermost_state);
2917 } else {
2918 // debug information already set. Check that it is correct from the current point of view
2919 DEBUG_ONLY(assert_equal(info->_scope_debug_info, compute_debug_info_for_scope(op_id, innermost_scope, innermost_state, innermost_state)));
2920 }
2921 }
2922
2923
2924 void LinearScan::assign_reg_num(LIR_OpList* instructions, IntervalWalker* iw) {
2925 LIR_OpVisitState visitor;
2926 int num_inst = instructions->length();
2927 bool has_dead = false;
2928
2929 for (int j = 0; j < num_inst; j++) {
2930 LIR_Op* op = instructions->at(j);
2931 if (op == NULL) { // this can happen when spill-moves are removed in eliminate_spill_moves
2932 has_dead = true;
2933 continue;
2934 }
2935 int op_id = op->id();
2936
2937 // visit instruction to get list of operands
2938 visitor.visit(op);
2939
2940 // iterate all modes of the visitor and process all virtual operands
2941 for_each_visitor_mode(mode) {
2942 int n = visitor.opr_count(mode);
2943 for (int k = 0; k < n; k++) {
2944 LIR_Opr opr = visitor.opr_at(mode, k);
2945 if (opr->is_virtual_register()) {
2946 visitor.set_opr_at(mode, k, color_lir_opr(opr, op_id, mode));
2947 }
2948 }
2949 }
2950
2951 if (visitor.info_count() > 0) {
2952 // exception handling
2953 if (compilation()->has_exception_handlers()) {
2954 XHandlers* xhandlers = visitor.all_xhandler();
2955 int n = xhandlers->length();
2956 for (int k = 0; k < n; k++) {
2957 XHandler* handler = xhandlers->handler_at(k);
2958 if (handler->entry_code() != NULL) {
2959 assign_reg_num(handler->entry_code()->instructions_list(), NULL);
2960 }
2961 }
2962 } else {
2963 assert(visitor.all_xhandler()->length() == 0, "missed exception handler");
2964 }
2965
2966 // compute oop map
2967 assert(iw != NULL, "needed for compute_oop_map");
2968 compute_oop_map(iw, visitor, op);
2969
2970 // compute debug information
2971 if (!use_fpu_stack_allocation()) {
2972 // compute debug information if fpu stack allocation is not needed.
2973 // when fpu stack allocation is needed, the debug information can not
2974 // be computed here because the exact location of fpu operands is not known
2975 // -> debug information is created inside the fpu stack allocator
2976 int n = visitor.info_count();
2977 for (int k = 0; k < n; k++) {
2978 compute_debug_info(visitor.info_at(k), op_id);
2979 }
2980 }
2981 }
2982
2983 #ifdef ASSERT
2984 // make sure we haven't made the op invalid.
2985 op->verify();
2986 #endif
2987
2988 // remove useless moves
2989 if (op->code() == lir_move) {
2990 assert(op->as_Op1() != NULL, "move must be LIR_Op1");
2991 LIR_Op1* move = (LIR_Op1*)op;
2992 LIR_Opr src = move->in_opr();
2993 LIR_Opr dst = move->result_opr();
2994 if (dst == src ||
2995 !dst->is_pointer() && !src->is_pointer() &&
2996 src->is_same_register(dst)) {
2997 instructions->at_put(j, NULL);
2998 has_dead = true;
2999 }
3000 }
3001 }
3002
3003 if (has_dead) {
3004 // iterate all instructions of the block and remove all null-values.
3005 int insert_point = 0;
3006 for (int j = 0; j < num_inst; j++) {
3007 LIR_Op* op = instructions->at(j);
3008 if (op != NULL) {
3009 if (insert_point != j) {
3010 instructions->at_put(insert_point, op);
3011 }
3012 insert_point++;
3013 }
3014 }
3015 instructions->truncate(insert_point);
3016 }
3017 }
3018
3019 void LinearScan::assign_reg_num() {
3020 TIME_LINEAR_SCAN(timer_assign_reg_num);
3021
3022 init_compute_debug_info();
3023 IntervalWalker* iw = init_compute_oop_maps();
3024
3025 int num_blocks = block_count();
3026 for (int i = 0; i < num_blocks; i++) {
3027 BlockBegin* block = block_at(i);
3028 assign_reg_num(block->lir()->instructions_list(), iw);
3029 }
3030 }
3031
3032
3033 void LinearScan::do_linear_scan() {
3034 NOT_PRODUCT(_total_timer.begin_method());
3035
3036 number_instructions();
3037
3038 NOT_PRODUCT(print_lir(1, "Before Register Allocation"));
3039
3040 compute_local_live_sets();
3041 compute_global_live_sets();
3042 CHECK_BAILOUT();
3043
3044 build_intervals();
3045 CHECK_BAILOUT();
3046 sort_intervals_before_allocation();
3047
3048 NOT_PRODUCT(print_intervals("Before Register Allocation"));
3049 NOT_PRODUCT(LinearScanStatistic::compute(this, _stat_before_alloc));
3050
3051 allocate_registers();
3052 CHECK_BAILOUT();
3053
3054 resolve_data_flow();
3055 if (compilation()->has_exception_handlers()) {
3056 resolve_exception_handlers();
3057 }
3058 // fill in number of spill slots into frame_map
3059 propagate_spill_slots();
3060 CHECK_BAILOUT();
3061
3062 NOT_PRODUCT(print_intervals("After Register Allocation"));
3063 NOT_PRODUCT(print_lir(2, "LIR after register allocation:"));
3064
3065 sort_intervals_after_allocation();
3066
3067 DEBUG_ONLY(verify());
3068
3069 eliminate_spill_moves();
3070 assign_reg_num();
3071 CHECK_BAILOUT();
3072
3073 NOT_PRODUCT(print_lir(2, "LIR after assignment of register numbers:"));
3074 NOT_PRODUCT(LinearScanStatistic::compute(this, _stat_after_asign));
3075
3076 { TIME_LINEAR_SCAN(timer_allocate_fpu_stack);
3077
3078 if (use_fpu_stack_allocation()) {
3079 allocate_fpu_stack(); // Only has effect on Intel
3080 NOT_PRODUCT(print_lir(2, "LIR after FPU stack allocation:"));
3081 }
3082 }
3083
3084 { TIME_LINEAR_SCAN(timer_optimize_lir);
3085
3086 EdgeMoveOptimizer::optimize(ir()->code());
3087 ControlFlowOptimizer::optimize(ir()->code());
3088 // check that cfg is still correct after optimizations
3089 ir()->verify();
3090 }
3091
3092 NOT_PRODUCT(print_lir(1, "Before Code Generation", false));
3093 NOT_PRODUCT(LinearScanStatistic::compute(this, _stat_final));
3094 NOT_PRODUCT(_total_timer.end_method(this));
3095 }
3096
3097
3098 // ********** Printing functions
3099
3100 #ifndef PRODUCT
3101
3102 void LinearScan::print_timers(double total) {
3103 _total_timer.print(total);
3104 }
3105
3106 void LinearScan::print_statistics() {
3107 _stat_before_alloc.print("before allocation");
3108 _stat_after_asign.print("after assignment of register");
3109 _stat_final.print("after optimization");
3110 }
3111
3112 void LinearScan::print_bitmap(BitMap& b) {
3113 for (unsigned int i = 0; i < b.size(); i++) {
3114 if (b.at(i)) tty->print("%d ", i);
3115 }
3116 tty->cr();
3117 }
3118
3119 void LinearScan::print_intervals(const char* label) {
3120 if (TraceLinearScanLevel >= 1) {
3121 int i;
3122 tty->cr();
3123 tty->print_cr("%s", label);
3124
3125 for (i = 0; i < interval_count(); i++) {
3126 Interval* interval = interval_at(i);
3127 if (interval != NULL) {
3128 interval->print();
3129 }
3130 }
3131
3132 tty->cr();
3133 tty->print_cr("--- Basic Blocks ---");
3134 for (i = 0; i < block_count(); i++) {
3135 BlockBegin* block = block_at(i);
3136 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());
3137 }
3138 tty->cr();
3139 tty->cr();
3140 }
3141
3142 if (PrintCFGToFile) {
3143 CFGPrinter::print_intervals(&_intervals, label);
3144 }
3145 }
3146
3147 void LinearScan::print_lir(int level, const char* label, bool hir_valid) {
3148 if (TraceLinearScanLevel >= level) {
3149 tty->cr();
3150 tty->print_cr("%s", label);
3151 print_LIR(ir()->linear_scan_order());
3152 tty->cr();
3153 }
3154
3155 if (level == 1 && PrintCFGToFile) {
3156 CFGPrinter::print_cfg(ir()->linear_scan_order(), label, hir_valid, true);
3157 }
3158 }
3159
3160 #endif //PRODUCT
3161
3162
3163 // ********** verification functions for allocation
3164 // (check that all intervals have a correct register and that no registers are overwritten)
3165 #ifdef ASSERT
3166
3167 void LinearScan::verify() {
3168 TRACE_LINEAR_SCAN(2, tty->print_cr("********* verifying intervals ******************************************"));
3169 verify_intervals();
3170
3171 TRACE_LINEAR_SCAN(2, tty->print_cr("********* verifying that no oops are in fixed intervals ****************"));
3172 verify_no_oops_in_fixed_intervals();
3173
3174 TRACE_LINEAR_SCAN(2, tty->print_cr("********* verifying that unpinned constants are not alive across block boundaries"));
3175 verify_constants();
3176
3177 TRACE_LINEAR_SCAN(2, tty->print_cr("********* verifying register allocation ********************************"));
3178 verify_registers();
3179
3180 TRACE_LINEAR_SCAN(2, tty->print_cr("********* no errors found **********************************************"));
3181 }
3182
3183 void LinearScan::verify_intervals() {
3184 int len = interval_count();
3185 bool has_error = false;
3186
3187 for (int i = 0; i < len; i++) {
3188 Interval* i1 = interval_at(i);
3189 if (i1 == NULL) continue;
3190
3191 i1->check_split_children();
3192
3193 if (i1->reg_num() != i) {
3194 tty->print_cr("Interval %d is on position %d in list", i1->reg_num(), i); i1->print(); tty->cr();
3195 has_error = true;
3196 }
3197
3198 if (i1->reg_num() >= LIR_OprDesc::vreg_base && i1->type() == T_ILLEGAL) {
3199 tty->print_cr("Interval %d has no type assigned", i1->reg_num()); i1->print(); tty->cr();
3200 has_error = true;
3201 }
3202
3203 if (i1->assigned_reg() == any_reg) {
3204 tty->print_cr("Interval %d has no register assigned", i1->reg_num()); i1->print(); tty->cr();
3205 has_error = true;
3206 }
3207
3208 if (i1->assigned_reg() == i1->assigned_regHi()) {
3209 tty->print_cr("Interval %d: low and high register equal", i1->reg_num()); i1->print(); tty->cr();
3210 has_error = true;
3211 }
3212
3213 if (!is_processed_reg_num(i1->assigned_reg())) {
3214 tty->print_cr("Can not have an Interval for an ignored register"); i1->print(); tty->cr();
3215 has_error = true;
3216 }
3217
3218 if (i1->first() == Range::end()) {
3219 tty->print_cr("Interval %d has no Range", i1->reg_num()); i1->print(); tty->cr();
3220 has_error = true;
3221 }
3222
3223 for (Range* r = i1->first(); r != Range::end(); r = r->next()) {
3224 if (r->from() >= r->to()) {
3225 tty->print_cr("Interval %d has zero length range", i1->reg_num()); i1->print(); tty->cr();
3226 has_error = true;
3227 }
3228 }
3229
3230 for (int j = i + 1; j < len; j++) {
3231 Interval* i2 = interval_at(j);
3232 if (i2 == NULL) continue;
3233
3234 // special intervals that are created in MoveResolver
3235 // -> ignore them because the range information has no meaning there
3236 if (i1->from() == 1 && i1->to() == 2) continue;
3237 if (i2->from() == 1 && i2->to() == 2) continue;
3238
3239 int r1 = i1->assigned_reg();
3240 int r1Hi = i1->assigned_regHi();
3241 int r2 = i2->assigned_reg();
3242 int r2Hi = i2->assigned_regHi();
3243 if (i1->intersects(i2) && (r1 == r2 || r1 == r2Hi || (r1Hi != any_reg && (r1Hi == r2 || r1Hi == r2Hi)))) {
3244 tty->print_cr("Intervals %d and %d overlap and have the same register assigned", i1->reg_num(), i2->reg_num());
3245 i1->print(); tty->cr();
3246 i2->print(); tty->cr();
3247 has_error = true;
3248 }
3249 }
3250 }
3251
3252 assert(has_error == false, "register allocation invalid");
3253 }
3254
3255
3256 void LinearScan::verify_no_oops_in_fixed_intervals() {
3257 Interval* fixed_intervals;
3258 Interval* other_intervals;
3259 create_unhandled_lists(&fixed_intervals, &other_intervals, is_precolored_cpu_interval, NULL);
3260
3261 // to ensure a walking until the last instruction id, add a dummy interval
3262 // with a high operation id
3263 other_intervals = new Interval(any_reg);
3264 other_intervals->add_range(max_jint - 2, max_jint - 1);
3265 IntervalWalker* iw = new IntervalWalker(this, fixed_intervals, other_intervals);
3266
3267 LIR_OpVisitState visitor;
3268 for (int i = 0; i < block_count(); i++) {
3269 BlockBegin* block = block_at(i);
3270
3271 LIR_OpList* instructions = block->lir()->instructions_list();
3272
3273 for (int j = 0; j < instructions->length(); j++) {
3274 LIR_Op* op = instructions->at(j);
3275 int op_id = op->id();
3276
3277 visitor.visit(op);
3278
3279 if (visitor.info_count() > 0) {
3280 iw->walk_before(op->id());
3281 bool check_live = true;
3282 if (op->code() == lir_move) {
3283 LIR_Op1* move = (LIR_Op1*)op;
3284 check_live = (move->patch_code() == lir_patch_none);
3285 }
3286 LIR_OpBranch* branch = op->as_OpBranch();
3287 if (branch != NULL && branch->stub() != NULL && branch->stub()->is_exception_throw_stub()) {
3288 // Don't bother checking the stub in this case since the
3289 // exception stub will never return to normal control flow.
3290 check_live = false;
3291 }
3292
3293 // Make sure none of the fixed registers is live across an
3294 // oopmap since we can't handle that correctly.
3295 if (check_live) {
3296 for (Interval* interval = iw->active_first(fixedKind);
3297 interval != Interval::end();
3298 interval = interval->next()) {
3299 if (interval->current_to() > op->id() + 1) {
3300 // This interval is live out of this op so make sure
3301 // that this interval represents some value that's
3302 // referenced by this op either as an input or output.
3303 bool ok = false;
3304 for_each_visitor_mode(mode) {
3305 int n = visitor.opr_count(mode);
3306 for (int k = 0; k < n; k++) {
3307 LIR_Opr opr = visitor.opr_at(mode, k);
3308 if (opr->is_fixed_cpu()) {
3309 if (interval_at(reg_num(opr)) == interval) {
3310 ok = true;
3311 break;
3312 }
3313 int hi = reg_numHi(opr);
3314 if (hi != -1 && interval_at(hi) == interval) {
3315 ok = true;
3316 break;
3317 }
3318 }
3319 }
3320 }
3321 assert(ok, "fixed intervals should never be live across an oopmap point");
3322 }
3323 }
3324 }
3325 }
3326
3327 // oop-maps at calls do not contain registers, so check is not needed
3328 if (!visitor.has_call()) {
3329
3330 for_each_visitor_mode(mode) {
3331 int n = visitor.opr_count(mode);
3332 for (int k = 0; k < n; k++) {
3333 LIR_Opr opr = visitor.opr_at(mode, k);
3334
3335 if (opr->is_fixed_cpu() && opr->is_oop()) {
3336 // operand is a non-virtual cpu register and contains an oop
3337 TRACE_LINEAR_SCAN(4, op->print_on(tty); tty->print("checking operand "); opr->print(); tty->cr());
3338
3339 Interval* interval = interval_at(reg_num(opr));
3340 assert(interval != NULL, "no interval");
3341
3342 if (mode == LIR_OpVisitState::inputMode) {
3343 if (interval->to() >= op_id + 1) {
3344 assert(interval->to() < op_id + 2 ||
3345 interval->has_hole_between(op_id, op_id + 2),
3346 "oop input operand live after instruction");
3347 }
3348 } else if (mode == LIR_OpVisitState::outputMode) {
3349 if (interval->from() <= op_id - 1) {
3350 assert(interval->has_hole_between(op_id - 1, op_id),
3351 "oop input operand live after instruction");
3352 }
3353 }
3354 }
3355 }
3356 }
3357 }
3358 }
3359 }
3360 }
3361
3362
3363 void LinearScan::verify_constants() {
3364 int num_regs = num_virtual_regs();
3365 int size = live_set_size();
3366 int num_blocks = block_count();
3367
3368 for (int i = 0; i < num_blocks; i++) {
3369 BlockBegin* block = block_at(i);
3370 BitMap live_at_edge = block->live_in();
3371
3372 // visit all registers where the live_at_edge bit is set
3373 for (int r = (int)live_at_edge.get_next_one_offset(0, size); r < size; r = (int)live_at_edge.get_next_one_offset(r + 1, size)) {
3374 TRACE_LINEAR_SCAN(4, tty->print("checking interval %d of block B%d", r, block->block_id()));
3375
3376 Value value = gen()->instruction_for_vreg(r);
3377
3378 assert(value != NULL, "all intervals live across block boundaries must have Value");
3379 assert(value->operand()->is_register() && value->operand()->is_virtual(), "value must have virtual operand");
3380 assert(value->operand()->vreg_number() == r, "register number must match");
3381 // TKR assert(value->as_Constant() == NULL || value->is_pinned(), "only pinned constants can be alive accross block boundaries");
3382 }
3383 }
3384 }
3385
3386
3387 class RegisterVerifier: public StackObj {
3388 private:
3389 LinearScan* _allocator;
3390 BlockList _work_list; // all blocks that must be processed
3391 IntervalsList _saved_states; // saved information of previous check
3392
3393 // simplified access to methods of LinearScan
3394 Compilation* compilation() const { return _allocator->compilation(); }
3395 Interval* interval_at(int reg_num) const { return _allocator->interval_at(reg_num); }
3396 int reg_num(LIR_Opr opr) const { return _allocator->reg_num(opr); }
3397
3398 // currently, only registers are processed
3399 int state_size() { return LinearScan::nof_regs; }
3400
3401 // accessors
3402 IntervalList* state_for_block(BlockBegin* block) { return _saved_states.at(block->block_id()); }
3403 void set_state_for_block(BlockBegin* block, IntervalList* saved_state) { _saved_states.at_put(block->block_id(), saved_state); }
3404 void add_to_work_list(BlockBegin* block) { if (!_work_list.contains(block)) _work_list.append(block); }
3405
3406 // helper functions
3407 IntervalList* copy(IntervalList* input_state);
3408 void state_put(IntervalList* input_state, int reg, Interval* interval);
3409 bool check_state(IntervalList* input_state, int reg, Interval* interval);
3410
3411 void process_block(BlockBegin* block);
3412 void process_xhandler(XHandler* xhandler, IntervalList* input_state);
3413 void process_successor(BlockBegin* block, IntervalList* input_state);
3414 void process_operations(LIR_List* ops, IntervalList* input_state);
3415
3416 public:
3417 RegisterVerifier(LinearScan* allocator)
3418 : _allocator(allocator)
3419 , _work_list(16)
3420 , _saved_states(BlockBegin::number_of_blocks(), NULL)
3421 { }
3422
3423 void verify(BlockBegin* start);
3424 };
3425
3426
3427 // entry function from LinearScan that starts the verification
3428 void LinearScan::verify_registers() {
3429 RegisterVerifier verifier(this);
3430 verifier.verify(block_at(0));
3431 }
3432
3433
3434 void RegisterVerifier::verify(BlockBegin* start) {
3435 // setup input registers (method arguments) for first block
3436 IntervalList* input_state = new IntervalList(state_size(), NULL);
3437 CallingConvention* args = compilation()->frame_map()->incoming_arguments();
3438 for (int n = 0; n < args->length(); n++) {
3439 LIR_Opr opr = args->at(n);
3440 if (opr->is_register()) {
3441 Interval* interval = interval_at(reg_num(opr));
3442
3443 if (interval->assigned_reg() < state_size()) {
3444 input_state->at_put(interval->assigned_reg(), interval);
3445 }
3446 if (interval->assigned_regHi() != LinearScan::any_reg && interval->assigned_regHi() < state_size()) {
3447 input_state->at_put(interval->assigned_regHi(), interval);
3448 }
3449 }
3450 }
3451
3452 set_state_for_block(start, input_state);
3453 add_to_work_list(start);
3454
3455 // main loop for verification
3456 do {
3457 BlockBegin* block = _work_list.at(0);
3458 _work_list.remove_at(0);
3459
3460 process_block(block);
3461 } while (!_work_list.is_empty());
3462 }
3463
3464 void RegisterVerifier::process_block(BlockBegin* block) {
3465 TRACE_LINEAR_SCAN(2, tty->cr(); tty->print_cr("process_block B%d", block->block_id()));
3466
3467 // must copy state because it is modified
3468 IntervalList* input_state = copy(state_for_block(block));
3469
3470 if (TraceLinearScanLevel >= 4) {
3471 tty->print_cr("Input-State of intervals:");
3472 tty->print(" ");
3473 for (int i = 0; i < state_size(); i++) {
3474 if (input_state->at(i) != NULL) {
3475 tty->print(" %4d", input_state->at(i)->reg_num());
3476 } else {
3477 tty->print(" __");
3478 }
3479 }
3480 tty->cr();
3481 tty->cr();
3482 }
3483
3484 // process all operations of the block
3485 process_operations(block->lir(), input_state);
3486
3487 // iterate all successors
3488 for (int i = 0; i < block->number_of_sux(); i++) {
3489 process_successor(block->sux_at(i), input_state);
3490 }
3491 }
3492
3493 void RegisterVerifier::process_xhandler(XHandler* xhandler, IntervalList* input_state) {
3494 TRACE_LINEAR_SCAN(2, tty->print_cr("process_xhandler B%d", xhandler->entry_block()->block_id()));
3495
3496 // must copy state because it is modified
3497 input_state = copy(input_state);
3498
3499 if (xhandler->entry_code() != NULL) {
3500 process_operations(xhandler->entry_code(), input_state);
3501 }
3502 process_successor(xhandler->entry_block(), input_state);
3503 }
3504
3505 void RegisterVerifier::process_successor(BlockBegin* block, IntervalList* input_state) {
3506 IntervalList* saved_state = state_for_block(block);
3507
3508 if (saved_state != NULL) {
3509 // this block was already processed before.
3510 // check if new input_state is consistent with saved_state
3511
3512 bool saved_state_correct = true;
3513 for (int i = 0; i < state_size(); i++) {
3514 if (input_state->at(i) != saved_state->at(i)) {
3515 // current input_state and previous saved_state assume a different
3516 // interval in this register -> assume that this register is invalid
3517 if (saved_state->at(i) != NULL) {
3518 // invalidate old calculation only if it assumed that
3519 // register was valid. when the register was already invalid,
3520 // then the old calculation was correct.
3521 saved_state_correct = false;
3522 saved_state->at_put(i, NULL);
3523
3524 TRACE_LINEAR_SCAN(4, tty->print_cr("process_successor B%d: invalidating slot %d", block->block_id(), i));
3525 }
3526 }
3527 }
3528
3529 if (saved_state_correct) {
3530 // already processed block with correct input_state
3531 TRACE_LINEAR_SCAN(2, tty->print_cr("process_successor B%d: previous visit already correct", block->block_id()));
3532 } else {
3533 // must re-visit this block
3534 TRACE_LINEAR_SCAN(2, tty->print_cr("process_successor B%d: must re-visit because input state changed", block->block_id()));
3535 add_to_work_list(block);
3536 }
3537
3538 } else {
3539 // block was not processed before, so set initial input_state
3540 TRACE_LINEAR_SCAN(2, tty->print_cr("process_successor B%d: initial visit", block->block_id()));
3541
3542 set_state_for_block(block, copy(input_state));
3543 add_to_work_list(block);
3544 }
3545 }
3546
3547
3548 IntervalList* RegisterVerifier::copy(IntervalList* input_state) {
3549 IntervalList* copy_state = new IntervalList(input_state->length());
3550 copy_state->push_all(input_state);
3551 return copy_state;
3552 }
3553
3554 void RegisterVerifier::state_put(IntervalList* input_state, int reg, Interval* interval) {
3555 if (reg != LinearScan::any_reg && reg < state_size()) {
3556 if (interval != NULL) {
3557 TRACE_LINEAR_SCAN(4, tty->print_cr(" reg[%d] = %d", reg, interval->reg_num()));
3558 } else if (input_state->at(reg) != NULL) {
3559 TRACE_LINEAR_SCAN(4, tty->print_cr(" reg[%d] = NULL", reg));
3560 }
3561
3562 input_state->at_put(reg, interval);
3563 }
3564 }
3565
3566 bool RegisterVerifier::check_state(IntervalList* input_state, int reg, Interval* interval) {
3567 if (reg != LinearScan::any_reg && reg < state_size()) {
3568 if (input_state->at(reg) != interval) {
3569 tty->print_cr("!! Error in register allocation: register %d does not contain interval %d", reg, interval->reg_num());
3570 return true;
3571 }
3572 }
3573 return false;
3574 }
3575
3576 void RegisterVerifier::process_operations(LIR_List* ops, IntervalList* input_state) {
3577 // visit all instructions of the block
3578 LIR_OpVisitState visitor;
3579 bool has_error = false;
3580
3581 for (int i = 0; i < ops->length(); i++) {
3582 LIR_Op* op = ops->at(i);
3583 visitor.visit(op);
3584
3585 TRACE_LINEAR_SCAN(4, op->print_on(tty));
3586
3587 // check if input operands are correct
3588 int j;
3589 int n = visitor.opr_count(LIR_OpVisitState::inputMode);
3590 for (j = 0; j < n; j++) {
3591 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::inputMode, j);
3592 if (opr->is_register() && LinearScan::is_processed_reg_num(reg_num(opr))) {
3593 Interval* interval = interval_at(reg_num(opr));
3594 if (op->id() != -1) {
3595 interval = interval->split_child_at_op_id(op->id(), LIR_OpVisitState::inputMode);
3596 }
3597
3598 has_error |= check_state(input_state, interval->assigned_reg(), interval->split_parent());
3599 has_error |= check_state(input_state, interval->assigned_regHi(), interval->split_parent());
3600
3601 // When an operand is marked with is_last_use, then the fpu stack allocator
3602 // removes the register from the fpu stack -> the register contains no value
3603 if (opr->is_last_use()) {
3604 state_put(input_state, interval->assigned_reg(), NULL);
3605 state_put(input_state, interval->assigned_regHi(), NULL);
3606 }
3607 }
3608 }
3609
3610 // invalidate all caller save registers at calls
3611 if (visitor.has_call()) {
3612 for (j = 0; j < FrameMap::nof_caller_save_cpu_regs(); j++) {
3613 state_put(input_state, reg_num(FrameMap::caller_save_cpu_reg_at(j)), NULL);
3614 }
3615 for (j = 0; j < FrameMap::nof_caller_save_fpu_regs; j++) {
3616 state_put(input_state, reg_num(FrameMap::caller_save_fpu_reg_at(j)), NULL);
3617 }
3618
3619 #ifdef X86
3620 for (j = 0; j < FrameMap::nof_caller_save_xmm_regs; j++) {
3621 state_put(input_state, reg_num(FrameMap::caller_save_xmm_reg_at(j)), NULL);
3622 }
3623 #endif
3624 }
3625
3626 // process xhandler before output and temp operands
3627 XHandlers* xhandlers = visitor.all_xhandler();
3628 n = xhandlers->length();
3629 for (int k = 0; k < n; k++) {
3630 process_xhandler(xhandlers->handler_at(k), input_state);
3631 }
3632
3633 // set temp operands (some operations use temp operands also as output operands, so can't set them NULL)
3634 n = visitor.opr_count(LIR_OpVisitState::tempMode);
3635 for (j = 0; j < n; j++) {
3636 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::tempMode, j);
3637 if (opr->is_register() && LinearScan::is_processed_reg_num(reg_num(opr))) {
3638 Interval* interval = interval_at(reg_num(opr));
3639 if (op->id() != -1) {
3640 interval = interval->split_child_at_op_id(op->id(), LIR_OpVisitState::tempMode);
3641 }
3642
3643 state_put(input_state, interval->assigned_reg(), interval->split_parent());
3644 state_put(input_state, interval->assigned_regHi(), interval->split_parent());
3645 }
3646 }
3647
3648 // set output operands
3649 n = visitor.opr_count(LIR_OpVisitState::outputMode);
3650 for (j = 0; j < n; j++) {
3651 LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::outputMode, j);
3652 if (opr->is_register() && LinearScan::is_processed_reg_num(reg_num(opr))) {
3653 Interval* interval = interval_at(reg_num(opr));
3654 if (op->id() != -1) {
3655 interval = interval->split_child_at_op_id(op->id(), LIR_OpVisitState::outputMode);
3656 }
3657
3658 state_put(input_state, interval->assigned_reg(), interval->split_parent());
3659 state_put(input_state, interval->assigned_regHi(), interval->split_parent());
3660 }
3661 }
3662 }
3663 assert(has_error == false, "Error in register allocation");
3664 }
3665
3666 #endif // ASSERT
3667
3668
3669
3670 // **** Implementation of MoveResolver ******************************
3671
3672 MoveResolver::MoveResolver(LinearScan* allocator) :
3673 _allocator(allocator),
3674 _multiple_reads_allowed(false),
3675 _mapping_from(8),
3676 _mapping_from_opr(8),
3677 _mapping_to(8),
3678 _insert_list(NULL),
3679 _insert_idx(-1),
3680 _insertion_buffer()
3681 {
3682 for (int i = 0; i < LinearScan::nof_regs; i++) {
3683 _register_blocked[i] = 0;
3684 }
3685 DEBUG_ONLY(check_empty());
3686 }
3687
3688
3689 #ifdef ASSERT
3690
3691 void MoveResolver::check_empty() {
3692 assert(_mapping_from.length() == 0 && _mapping_from_opr.length() == 0 && _mapping_to.length() == 0, "list must be empty before and after processing");
3693 for (int i = 0; i < LinearScan::nof_regs; i++) {
3694 assert(register_blocked(i) == 0, "register map must be empty before and after processing");
3695 }
3696 assert(_multiple_reads_allowed == false, "must have default value");
3697 }
3698
3699 void MoveResolver::verify_before_resolve() {
3700 assert(_mapping_from.length() == _mapping_from_opr.length(), "length must be equal");
3701 assert(_mapping_from.length() == _mapping_to.length(), "length must be equal");
3702 assert(_insert_list != NULL && _insert_idx != -1, "insert position not set");
3703
3704 int i, j;
3705 if (!_multiple_reads_allowed) {
3706 for (i = 0; i < _mapping_from.length(); i++) {
3707 for (j = i + 1; j < _mapping_from.length(); j++) {
3708 assert(_mapping_from.at(i) == NULL || _mapping_from.at(i) != _mapping_from.at(j), "cannot read from same interval twice");
3709 }
3710 }
3711 }
3712
3713 for (i = 0; i < _mapping_to.length(); i++) {
3714 for (j = i + 1; j < _mapping_to.length(); j++) {
3715 assert(_mapping_to.at(i) != _mapping_to.at(j), "cannot write to same interval twice");
3716 }
3717 }
3718
3719
3720 BitMap used_regs(LinearScan::nof_regs + allocator()->frame_map()->argcount() + allocator()->max_spills());
3721 used_regs.clear();
3722 if (!_multiple_reads_allowed) {
3723 for (i = 0; i < _mapping_from.length(); i++) {
3724 Interval* it = _mapping_from.at(i);
3725 if (it != NULL) {
3726 assert(!used_regs.at(it->assigned_reg()), "cannot read from same register twice");
3727 used_regs.set_bit(it->assigned_reg());
3728
3729 if (it->assigned_regHi() != LinearScan::any_reg) {
3730 assert(!used_regs.at(it->assigned_regHi()), "cannot read from same register twice");
3731 used_regs.set_bit(it->assigned_regHi());
3732 }
3733 }
3734 }
3735 }
3736
3737 used_regs.clear();
3738 for (i = 0; i < _mapping_to.length(); i++) {
3739 Interval* it = _mapping_to.at(i);
3740 assert(!used_regs.at(it->assigned_reg()), "cannot write to same register twice");
3741 used_regs.set_bit(it->assigned_reg());
3742
3743 if (it->assigned_regHi() != LinearScan::any_reg) {
3744 assert(!used_regs.at(it->assigned_regHi()), "cannot write to same register twice");
3745 used_regs.set_bit(it->assigned_regHi());
3746 }
3747 }
3748
3749 used_regs.clear();
3750 for (i = 0; i < _mapping_from.length(); i++) {
3751 Interval* it = _mapping_from.at(i);
3752 if (it != NULL && it->assigned_reg() >= LinearScan::nof_regs) {
3753 used_regs.set_bit(it->assigned_reg());
3754 }
3755 }
3756 for (i = 0; i < _mapping_to.length(); i++) {
3757 Interval* it = _mapping_to.at(i);
3758 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");
3759 }
3760 }
3761
3762 #endif // ASSERT
3763
3764
3765 // mark assigned_reg and assigned_regHi of the interval as blocked
3766 void MoveResolver::block_registers(Interval* it) {
3767 int reg = it->assigned_reg();
3768 if (reg < LinearScan::nof_regs) {
3769 assert(_multiple_reads_allowed || register_blocked(reg) == 0, "register already marked as used");
3770 set_register_blocked(reg, 1);
3771 }
3772 reg = it->assigned_regHi();
3773 if (reg != LinearScan::any_reg && reg < LinearScan::nof_regs) {
3774 assert(_multiple_reads_allowed || register_blocked(reg) == 0, "register already marked as used");
3775 set_register_blocked(reg, 1);
3776 }
3777 }
3778
3779 // mark assigned_reg and assigned_regHi of the interval as unblocked
3780 void MoveResolver::unblock_registers(Interval* it) {
3781 int reg = it->assigned_reg();
3782 if (reg < LinearScan::nof_regs) {
3783 assert(register_blocked(reg) > 0, "register already marked as unused");
3784 set_register_blocked(reg, -1);
3785 }
3786 reg = it->assigned_regHi();
3787 if (reg != LinearScan::any_reg && reg < LinearScan::nof_regs) {
3788 assert(register_blocked(reg) > 0, "register already marked as unused");
3789 set_register_blocked(reg, -1);
3790 }
3791 }
3792
3793 // check if assigned_reg and assigned_regHi of the to-interval are not blocked (or only blocked by from)
3794 bool MoveResolver::save_to_process_move(Interval* from, Interval* to) {
3795 int from_reg = -1;
3796 int from_regHi = -1;
3797 if (from != NULL) {
3798 from_reg = from->assigned_reg();
3799 from_regHi = from->assigned_regHi();
3800 }
3801
3802 int reg = to->assigned_reg();
3803 if (reg < LinearScan::nof_regs) {
3804 if (register_blocked(reg) > 1 || (register_blocked(reg) == 1 && reg != from_reg && reg != from_regHi)) {
3805 return false;
3806 }
3807 }
3808 reg = to->assigned_regHi();
3809 if (reg != LinearScan::any_reg && reg < LinearScan::nof_regs) {
3810 if (register_blocked(reg) > 1 || (register_blocked(reg) == 1 && reg != from_reg && reg != from_regHi)) {
3811 return false;
3812 }
3813 }
3814
3815 return true;
3816 }
3817
3818
3819 void MoveResolver::create_insertion_buffer(LIR_List* list) {
3820 assert(!_insertion_buffer.initialized(), "overwriting existing buffer");
3821 _insertion_buffer.init(list);
3822 }
3823
3824 void MoveResolver::append_insertion_buffer() {
3825 if (_insertion_buffer.initialized()) {
3826 _insertion_buffer.lir_list()->append(&_insertion_buffer);
3827 }
3828 assert(!_insertion_buffer.initialized(), "must be uninitialized now");
3829
3830 _insert_list = NULL;
3831 _insert_idx = -1;
3832 }
3833
3834 void MoveResolver::insert_move(Interval* from_interval, Interval* to_interval) {
3835 assert(from_interval->reg_num() != to_interval->reg_num(), "from and to interval equal");
3836 assert(from_interval->type() == to_interval->type(), "move between different types");
3837 assert(_insert_list != NULL && _insert_idx != -1, "must setup insert position first");
3838 assert(_insertion_buffer.lir_list() == _insert_list, "wrong insertion buffer");
3839
3840 LIR_Opr from_opr = LIR_OprFact::virtual_register(from_interval->reg_num(), from_interval->type());
3841 LIR_Opr to_opr = LIR_OprFact::virtual_register(to_interval->reg_num(), to_interval->type());
3842
3843 if (!_multiple_reads_allowed) {
3844 // the last_use flag is an optimization for FPU stack allocation. When the same
3845 // input interval is used in more than one move, then it is too difficult to determine
3846 // if this move is really the last use.
3847 from_opr = from_opr->make_last_use();
3848 }
3849 _insertion_buffer.move(_insert_idx, from_opr, to_opr);
3850
3851 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()));
3852 }
3853
3854 void MoveResolver::insert_move(LIR_Opr from_opr, Interval* to_interval) {
3855 assert(from_opr->type() == to_interval->type(), "move between different types");
3856 assert(_insert_list != NULL && _insert_idx != -1, "must setup insert position first");
3857 assert(_insertion_buffer.lir_list() == _insert_list, "wrong insertion buffer");
3858
3859 LIR_Opr to_opr = LIR_OprFact::virtual_register(to_interval->reg_num(), to_interval->type());
3860 _insertion_buffer.move(_insert_idx, from_opr, to_opr);
3861
3862 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()));
3863 }
3864
3865
3866 void MoveResolver::resolve_mappings() {
3867 TRACE_LINEAR_SCAN(4, tty->print_cr("MoveResolver: resolving mappings for Block B%d, index %d", _insert_list->block() != NULL ? _insert_list->block()->block_id() : -1, _insert_idx));
3868 DEBUG_ONLY(verify_before_resolve());
3869
3870 // Block all registers that are used as input operands of a move.
3871 // When a register is blocked, no move to this register is emitted.
3872 // This is necessary for detecting cycles in moves.
3873 int i;
3874 for (i = _mapping_from.length() - 1; i >= 0; i--) {
3875 Interval* from_interval = _mapping_from.at(i);
3876 if (from_interval != NULL) {
3877 block_registers(from_interval);
3878 }
3879 }
3880
3881 int spill_candidate = -1;
3882 while (_mapping_from.length() > 0) {
3883 bool processed_interval = false;
3884
3885 for (i = _mapping_from.length() - 1; i >= 0; i--) {
3886 Interval* from_interval = _mapping_from.at(i);
3887 Interval* to_interval = _mapping_to.at(i);
3888
3889 if (save_to_process_move(from_interval, to_interval)) {
3890 // this inverval can be processed because target is free
3891 if (from_interval != NULL) {
3892 insert_move(from_interval, to_interval);
3893 unblock_registers(from_interval);
3894 } else {
3895 insert_move(_mapping_from_opr.at(i), to_interval);
3896 }
3897 _mapping_from.remove_at(i);
3898 _mapping_from_opr.remove_at(i);
3899 _mapping_to.remove_at(i);
3900
3901 processed_interval = true;
3902 } else if (from_interval != NULL && from_interval->assigned_reg() < LinearScan::nof_regs) {
3903 // this interval cannot be processed now because target is not free
3904 // it starts in a register, so it is a possible candidate for spilling
3905 spill_candidate = i;
3906 }
3907 }
3908
3909 if (!processed_interval) {
3910 // no move could be processed because there is a cycle in the move list
3911 // (e.g. r1 -> r2, r2 -> r1), so one interval must be spilled to memory
3912 assert(spill_candidate != -1, "no interval in register for spilling found");
3913
3914 // create a new spill interval and assign a stack slot to it
3915 Interval* from_interval = _mapping_from.at(spill_candidate);
3916 Interval* spill_interval = new Interval(-1);
3917 spill_interval->set_type(from_interval->type());
3918
3919 // add a dummy range because real position is difficult to calculate
3920 // Note: this range is a special case when the integrity of the allocation is checked
3921 spill_interval->add_range(1, 2);
3922
3923 // do not allocate a new spill slot for temporary interval, but
3924 // use spill slot assigned to from_interval. Otherwise moves from
3925 // one stack slot to another can happen (not allowed by LIR_Assembler
3926 int spill_slot = from_interval->canonical_spill_slot();
3927 if (spill_slot < 0) {
3928 spill_slot = allocator()->allocate_spill_slot(type2spill_size[spill_interval->type()] == 2);
3929 from_interval->set_canonical_spill_slot(spill_slot);
3930 }
3931 spill_interval->assign_reg(spill_slot);
3932 allocator()->append_interval(spill_interval);
3933
3934 TRACE_LINEAR_SCAN(4, tty->print_cr("created new Interval %d for spilling", spill_interval->reg_num()));
3935
3936 // insert a move from register to stack and update the mapping
3937 insert_move(from_interval, spill_interval);
3938 _mapping_from.at_put(spill_candidate, spill_interval);
3939 unblock_registers(from_interval);
3940 }
3941 }
3942
3943 // reset to default value
3944 _multiple_reads_allowed = false;
3945
3946 // check that all intervals have been processed
3947 DEBUG_ONLY(check_empty());
3948 }
3949
3950
3951 void MoveResolver::set_insert_position(LIR_List* insert_list, int insert_idx) {
3952 TRACE_LINEAR_SCAN(4, tty->print_cr("MoveResolver: setting insert position to Block B%d, index %d", insert_list->block() != NULL ? insert_list->block()->block_id() : -1, insert_idx));
3953 assert(_insert_list == NULL && _insert_idx == -1, "use move_insert_position instead of set_insert_position when data already set");
3954
3955 create_insertion_buffer(insert_list);
3956 _insert_list = insert_list;
3957 _insert_idx = insert_idx;
3958 }
3959
3960 void MoveResolver::move_insert_position(LIR_List* insert_list, int insert_idx) {
3961 TRACE_LINEAR_SCAN(4, tty->print_cr("MoveResolver: moving insert position to Block B%d, index %d", insert_list->block() != NULL ? insert_list->block()->block_id() : -1, insert_idx));
3962
3963 if (_insert_list != NULL && (insert_list != _insert_list || insert_idx != _insert_idx)) {
3964 // insert position changed -> resolve current mappings
3965 resolve_mappings();
3966 }
3967
3968 if (insert_list != _insert_list) {
3969 // block changed -> append insertion_buffer because it is
3970 // bound to a specific block and create a new insertion_buffer
3971 append_insertion_buffer();
3972 create_insertion_buffer(insert_list);
3973 }
3974
3975 _insert_list = insert_list;
3976 _insert_idx = insert_idx;
3977 }
3978
3979 void MoveResolver::add_mapping(Interval* from_interval, Interval* to_interval) {
3980 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()));
3981
3982 _mapping_from.append(from_interval);
3983 _mapping_from_opr.append(LIR_OprFact::illegalOpr);
3984 _mapping_to.append(to_interval);
3985 }
3986
3987
3988 void MoveResolver::add_mapping(LIR_Opr from_opr, Interval* to_interval) {
3989 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()));
3990 assert(from_opr->is_constant(), "only for constants");
3991
3992 _mapping_from.append(NULL);
3993 _mapping_from_opr.append(from_opr);
3994 _mapping_to.append(to_interval);
3995 }
3996
3997 void MoveResolver::resolve_and_append_moves() {
3998 if (has_mappings()) {
3999 resolve_mappings();
4000 }
4001 append_insertion_buffer();
4002 }
4003
4004
4005
4006 // **** Implementation of Range *************************************
4007
4008 Range::Range(int from, int to, Range* next) :
4009 _from(from),
4010 _to(to),
4011 _next(next)
4012 {
4013 }
4014
4015 // initialize sentinel
4016 Range* Range::_end = NULL;
4017 void Range::initialize(Arena* arena) {
4018 _end = new (arena) Range(max_jint, max_jint, NULL);
4019 }
4020
4021 int Range::intersects_at(Range* r2) const {
4022 const Range* r1 = this;
4023
4024 assert(r1 != NULL && r2 != NULL, "null ranges not allowed");
4025 assert(r1 != _end && r2 != _end, "empty ranges not allowed");
4026
4027 do {
4028 if (r1->from() < r2->from()) {
4029 if (r1->to() <= r2->from()) {
4030 r1 = r1->next(); if (r1 == _end) return -1;
4031 } else {
4032 return r2->from();
4033 }
4034 } else if (r2->from() < r1->from()) {
4035 if (r2->to() <= r1->from()) {
4036 r2 = r2->next(); if (r2 == _end) return -1;
4037 } else {
4038 return r1->from();
4039 }
4040 } else { // r1->from() == r2->from()
4041 if (r1->from() == r1->to()) {
4042 r1 = r1->next(); if (r1 == _end) return -1;
4043 } else if (r2->from() == r2->to()) {
4044 r2 = r2->next(); if (r2 == _end) return -1;
4045 } else {
4046 return r1->from();
4047 }
4048 }
4049 } while (true);
4050 }
4051
4052 #ifndef PRODUCT
4053 void Range::print(outputStream* out) const {
4054 out->print("[%d, %d[ ", _from, _to);
4055 }
4056 #endif
4057
4058
4059
4060 // **** Implementation of Interval **********************************
4061
4062 // initialize sentinel
4063 Interval* Interval::_end = NULL;
4064 void Interval::initialize(Arena* arena) {
4065 Range::initialize(arena);
4066 _end = new (arena) Interval(-1);
4067 }
4068
4069 Interval::Interval(int reg_num) :
4070 _reg_num(reg_num),
4071 _type(T_ILLEGAL),
4072 _first(Range::end()),
4073 _use_pos_and_kinds(12),
4074 _current(Range::end()),
4075 _next(_end),
4076 _state(invalidState),
4077 _assigned_reg(LinearScan::any_reg),
4078 _assigned_regHi(LinearScan::any_reg),
4079 _cached_to(-1),
4080 _cached_opr(LIR_OprFact::illegalOpr),
4081 _cached_vm_reg(VMRegImpl::Bad()),
4082 _split_children(0),
4083 _canonical_spill_slot(-1),
4084 _insert_move_when_activated(false),
4085 _register_hint(NULL),
4086 _spill_state(noDefinitionFound),
4087 _spill_definition_pos(-1)
4088 {
4089 _split_parent = this;
4090 _current_split_child = this;
4091 }
4092
4093 int Interval::calc_to() {
4094 assert(_first != Range::end(), "interval has no range");
4095
4096 Range* r = _first;
4097 while (r->next() != Range::end()) {
4098 r = r->next();
4099 }
4100 return r->to();
4101 }
4102
4103
4104 #ifdef ASSERT
4105 // consistency check of split-children
4106 void Interval::check_split_children() {
4107 if (_split_children.length() > 0) {
4108 assert(is_split_parent(), "only split parents can have children");
4109
4110 for (int i = 0; i < _split_children.length(); i++) {
4111 Interval* i1 = _split_children.at(i);
4112
4113 assert(i1->split_parent() == this, "not a split child of this interval");
4114 assert(i1->type() == type(), "must be equal for all split children");
4115 assert(i1->canonical_spill_slot() == canonical_spill_slot(), "must be equal for all split children");
4116
4117 for (int j = i + 1; j < _split_children.length(); j++) {
4118 Interval* i2 = _split_children.at(j);
4119
4120 assert(i1->reg_num() != i2->reg_num(), "same register number");
4121
4122 if (i1->from() < i2->from()) {
4123 assert(i1->to() <= i2->from() && i1->to() < i2->to(), "intervals overlapping");
4124 } else {
4125 assert(i2->from() < i1->from(), "intervals start at same op_id");
4126 assert(i2->to() <= i1->from() && i2->to() < i1->to(), "intervals overlapping");
4127 }
4128 }
4129 }
4130 }
4131 }
4132 #endif // ASSERT
4133
4134 Interval* Interval::register_hint(bool search_split_child) const {
4135 if (!search_split_child) {
4136 return _register_hint;
4137 }
4138
4139 if (_register_hint != NULL) {
4140 assert(_register_hint->is_split_parent(), "ony split parents are valid hint registers");
4141
4142 if (_register_hint->assigned_reg() >= 0 && _register_hint->assigned_reg() < LinearScan::nof_regs) {
4143 return _register_hint;
4144
4145 } else if (_register_hint->_split_children.length() > 0) {
4146 // search the first split child that has a register assigned
4147 int len = _register_hint->_split_children.length();
4148 for (int i = 0; i < len; i++) {
4149 Interval* cur = _register_hint->_split_children.at(i);
4150
4151 if (cur->assigned_reg() >= 0 && cur->assigned_reg() < LinearScan::nof_regs) {
4152 return cur;
4153 }
4154 }
4155 }
4156 }
4157
4158 // no hint interval found that has a register assigned
4159 return NULL;
4160 }
4161
4162
4163 Interval* Interval::split_child_at_op_id(int op_id, LIR_OpVisitState::OprMode mode) {
4164 assert(is_split_parent(), "can only be called for split parents");
4165 assert(op_id >= 0, "invalid op_id (method can not be called for spill moves)");
4166
4167 Interval* result;
4168 if (_split_children.length() == 0) {
4169 result = this;
4170 } else {
4171 result = NULL;
4172 int len = _split_children.length();
4173
4174 // in outputMode, the end of the interval (op_id == cur->to()) is not valid
4175 int to_offset = (mode == LIR_OpVisitState::outputMode ? 0 : 1);
4176
4177 int i;
4178 for (i = 0; i < len; i++) {
4179 Interval* cur = _split_children.at(i);
4180 if (cur->from() <= op_id && op_id < cur->to() + to_offset) {
4181 if (i > 0) {
4182 // exchange current split child to start of list (faster access for next call)
4183 _split_children.at_put(i, _split_children.at(0));
4184 _split_children.at_put(0, cur);
4185 }
4186
4187 // interval found
4188 result = cur;
4189 break;
4190 }
4191 }
4192
4193 #ifdef ASSERT
4194 for (i = 0; i < len; i++) {
4195 Interval* tmp = _split_children.at(i);
4196 if (tmp != result && tmp->from() <= op_id && op_id < tmp->to() + to_offset) {
4197 tty->print_cr("two valid result intervals found for op_id %d: %d and %d", op_id, result->reg_num(), tmp->reg_num());
4198 result->print();
4199 tmp->print();
4200 assert(false, "two valid result intervals found");
4201 }
4202 }
4203 #endif
4204 }
4205
4206 assert(result != NULL, "no matching interval found");
4207 assert(result->covers(op_id, mode), "op_id not covered by interval");
4208
4209 return result;
4210 }
4211
4212
4213 // returns the last split child that ends before the given op_id
4214 Interval* Interval::split_child_before_op_id(int op_id) {
4215 assert(op_id >= 0, "invalid op_id");
4216
4217 Interval* parent = split_parent();
4218 Interval* result = NULL;
4219
4220 int len = parent->_split_children.length();
4221 assert(len > 0, "no split children available");
4222
4223 for (int i = len - 1; i >= 0; i--) {
4224 Interval* cur = parent->_split_children.at(i);
4225 if (cur->to() <= op_id && (result == NULL || result->to() < cur->to())) {
4226 result = cur;
4227 }
4228 }
4229
4230 assert(result != NULL, "no split child found");
4231 return result;
4232 }
4233
4234
4235 // checks if op_id is covered by any split child
4236 bool Interval::split_child_covers(int op_id, LIR_OpVisitState::OprMode mode) {
4237 assert(is_split_parent(), "can only be called for split parents");
4238 assert(op_id >= 0, "invalid op_id (method can not be called for spill moves)");
4239
4240 if (_split_children.length() == 0) {
4241 // simple case if interval was not split
4242 return covers(op_id, mode);
4243
4244 } else {
4245 // extended case: check all split children
4246 int len = _split_children.length();
4247 for (int i = 0; i < len; i++) {
4248 Interval* cur = _split_children.at(i);
4249 if (cur->covers(op_id, mode)) {
4250 return true;
4251 }
4252 }
4253 return false;
4254 }
4255 }
4256
4257
4258 // Note: use positions are sorted descending -> first use has highest index
4259 int Interval::first_usage(IntervalUseKind min_use_kind) const {
4260 assert(LinearScan::is_virtual_interval(this), "cannot access use positions for fixed intervals");
4261
4262 for (int i = _use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
4263 if (_use_pos_and_kinds.at(i + 1) >= min_use_kind) {
4264 return _use_pos_and_kinds.at(i);
4265 }
4266 }
4267 return max_jint;
4268 }
4269
4270 int Interval::next_usage(IntervalUseKind min_use_kind, int from) const {
4271 assert(LinearScan::is_virtual_interval(this), "cannot access use positions for fixed intervals");
4272
4273 for (int i = _use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
4274 if (_use_pos_and_kinds.at(i) >= from && _use_pos_and_kinds.at(i + 1) >= min_use_kind) {
4275 return _use_pos_and_kinds.at(i);
4276 }
4277 }
4278 return max_jint;
4279 }
4280
4281 int Interval::next_usage_exact(IntervalUseKind exact_use_kind, int from) const {
4282 assert(LinearScan::is_virtual_interval(this), "cannot access use positions for fixed intervals");
4283
4284 for (int i = _use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
4285 if (_use_pos_and_kinds.at(i) >= from && _use_pos_and_kinds.at(i + 1) == exact_use_kind) {
4286 return _use_pos_and_kinds.at(i);
4287 }
4288 }
4289 return max_jint;
4290 }
4291
4292 int Interval::previous_usage(IntervalUseKind min_use_kind, int from) const {
4293 assert(LinearScan::is_virtual_interval(this), "cannot access use positions for fixed intervals");
4294
4295 int prev = 0;
4296 for (int i = _use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
4297 if (_use_pos_and_kinds.at(i) > from) {
4298 return prev;
4299 }
4300 if (_use_pos_and_kinds.at(i + 1) >= min_use_kind) {
4301 prev = _use_pos_and_kinds.at(i);
4302 }
4303 }
4304 return prev;
4305 }
4306
4307 void Interval::add_use_pos(int pos, IntervalUseKind use_kind) {
4308 assert(covers(pos, LIR_OpVisitState::inputMode), "use position not covered by live range");
4309
4310 // do not add use positions for precolored intervals because
4311 // they are never used
4312 if (use_kind != noUse && reg_num() >= LIR_OprDesc::vreg_base) {
4313 #ifdef ASSERT
4314 assert(_use_pos_and_kinds.length() % 2 == 0, "must be");
4315 for (int i = 0; i < _use_pos_and_kinds.length(); i += 2) {
4316 assert(pos <= _use_pos_and_kinds.at(i), "already added a use-position with lower position");
4317 assert(_use_pos_and_kinds.at(i + 1) >= firstValidKind && _use_pos_and_kinds.at(i + 1) <= lastValidKind, "invalid use kind");
4318 if (i > 0) {
4319 assert(_use_pos_and_kinds.at(i) < _use_pos_and_kinds.at(i - 2), "not sorted descending");
4320 }
4321 }
4322 #endif
4323
4324 // Note: add_use is called in descending order, so list gets sorted
4325 // automatically by just appending new use positions
4326 int len = _use_pos_and_kinds.length();
4327 if (len == 0 || _use_pos_and_kinds.at(len - 2) > pos) {
4328 _use_pos_and_kinds.append(pos);
4329 _use_pos_and_kinds.append(use_kind);
4330 } else if (_use_pos_and_kinds.at(len - 1) < use_kind) {
4331 assert(_use_pos_and_kinds.at(len - 2) == pos, "list not sorted correctly");
4332 _use_pos_and_kinds.at_put(len - 1, use_kind);
4333 }
4334 }
4335 }
4336
4337 void Interval::add_range(int from, int to) {
4338 assert(from < to, "invalid range");
4339 assert(first() == Range::end() || to < first()->next()->from(), "not inserting at begin of interval");
4340 assert(from <= first()->to(), "not inserting at begin of interval");
4341
4342 if (first()->from() <= to) {
4343 // join intersecting ranges
4344 first()->set_from(MIN2(from, first()->from()));
4345 first()->set_to (MAX2(to, first()->to()));
4346 } else {
4347 // insert new range
4348 _first = new Range(from, to, first());
4349 }
4350 }
4351
4352 Interval* Interval::new_split_child() {
4353 // allocate new interval
4354 Interval* result = new Interval(-1);
4355 result->set_type(type());
4356
4357 Interval* parent = split_parent();
4358 result->_split_parent = parent;
4359 result->set_register_hint(parent);
4360
4361 // insert new interval in children-list of parent
4362 if (parent->_split_children.length() == 0) {
4363 assert(is_split_parent(), "list must be initialized at first split");
4364
4365 parent->_split_children = IntervalList(4);
4366 parent->_split_children.append(this);
4367 }
4368 parent->_split_children.append(result);
4369
4370 return result;
4371 }
4372
4373 // split this interval at the specified position and return
4374 // the remainder as a new interval.
4375 //
4376 // when an interval is split, a bi-directional link is established between the original interval
4377 // (the split parent) and the intervals that are split off this interval (the split children)
4378 // When a split child is split again, the new created interval is also a direct child
4379 // of the original parent (there is no tree of split children stored, but a flat list)
4380 // All split children are spilled to the same stack slot (stored in _canonical_spill_slot)
4381 //
4382 // Note: The new interval has no valid reg_num
4383 Interval* Interval::split(int split_pos) {
4384 assert(LinearScan::is_virtual_interval(this), "cannot split fixed intervals");
4385
4386 // allocate new interval
4387 Interval* result = new_split_child();
4388
4389 // split the ranges
4390 Range* prev = NULL;
4391 Range* cur = _first;
4392 while (cur != Range::end() && cur->to() <= split_pos) {
4393 prev = cur;
4394 cur = cur->next();
4395 }
4396 assert(cur != Range::end(), "split interval after end of last range");
4397
4398 if (cur->from() < split_pos) {
4399 result->_first = new Range(split_pos, cur->to(), cur->next());
4400 cur->set_to(split_pos);
4401 cur->set_next(Range::end());
4402
4403 } else {
4404 assert(prev != NULL, "split before start of first range");
4405 result->_first = cur;
4406 prev->set_next(Range::end());
4407 }
4408 result->_current = result->_first;
4409 _cached_to = -1; // clear cached value
4410
4411 // split list of use positions
4412 int total_len = _use_pos_and_kinds.length();
4413 int start_idx = total_len - 2;
4414 while (start_idx >= 0 && _use_pos_and_kinds.at(start_idx) < split_pos) {
4415 start_idx -= 2;
4416 }
4417
4418 intStack new_use_pos_and_kinds(total_len - start_idx);
4419 int i;
4420 for (i = start_idx + 2; i < total_len; i++) {
4421 new_use_pos_and_kinds.append(_use_pos_and_kinds.at(i));
4422 }
4423
4424 _use_pos_and_kinds.truncate(start_idx + 2);
4425 result->_use_pos_and_kinds = _use_pos_and_kinds;
4426 _use_pos_and_kinds = new_use_pos_and_kinds;
4427
4428 #ifdef ASSERT
4429 assert(_use_pos_and_kinds.length() % 2 == 0, "must have use kind for each use pos");
4430 assert(result->_use_pos_and_kinds.length() % 2 == 0, "must have use kind for each use pos");
4431 assert(_use_pos_and_kinds.length() + result->_use_pos_and_kinds.length() == total_len, "missed some entries");
4432
4433 for (i = 0; i < _use_pos_and_kinds.length(); i += 2) {
4434 assert(_use_pos_and_kinds.at(i) < split_pos, "must be");
4435 assert(_use_pos_and_kinds.at(i + 1) >= firstValidKind && _use_pos_and_kinds.at(i + 1) <= lastValidKind, "invalid use kind");
4436 }
4437 for (i = 0; i < result->_use_pos_and_kinds.length(); i += 2) {
4438 assert(result->_use_pos_and_kinds.at(i) >= split_pos, "must be");
4439 assert(result->_use_pos_and_kinds.at(i + 1) >= firstValidKind && result->_use_pos_and_kinds.at(i + 1) <= lastValidKind, "invalid use kind");
4440 }
4441 #endif
4442
4443 return result;
4444 }
4445
4446 // split this interval at the specified position and return
4447 // the head as a new interval (the original interval is the tail)
4448 //
4449 // Currently, only the first range can be split, and the new interval
4450 // must not have split positions
4451 Interval* Interval::split_from_start(int split_pos) {
4452 assert(LinearScan::is_virtual_interval(this), "cannot split fixed intervals");
4453 assert(split_pos > from() && split_pos < to(), "can only split inside interval");
4454 assert(split_pos > _first->from() && split_pos <= _first->to(), "can only split inside first range");
4455 assert(first_usage(noUse) > split_pos, "can not split when use positions are present");
4456
4457 // allocate new interval
4458 Interval* result = new_split_child();
4459
4460 // the new created interval has only one range (checked by assertion above),
4461 // so the splitting of the ranges is very simple
4462 result->add_range(_first->from(), split_pos);
4463
4464 if (split_pos == _first->to()) {
4465 assert(_first->next() != Range::end(), "must not be at end");
4466 _first = _first->next();
4467 } else {
4468 _first->set_from(split_pos);
4469 }
4470
4471 return result;
4472 }
4473
4474
4475 // returns true if the op_id is inside the interval
4476 bool Interval::covers(int op_id, LIR_OpVisitState::OprMode mode) const {
4477 Range* cur = _first;
4478
4479 while (cur != Range::end() && cur->to() < op_id) {
4480 cur = cur->next();
4481 }
4482 if (cur != Range::end()) {
4483 assert(cur->to() != cur->next()->from(), "ranges not separated");
4484
4485 if (mode == LIR_OpVisitState::outputMode) {
4486 return cur->from() <= op_id && op_id < cur->to();
4487 } else {
4488 return cur->from() <= op_id && op_id <= cur->to();
4489 }
4490 }
4491 return false;
4492 }
4493
4494 // returns true if the interval has any hole between hole_from and hole_to
4495 // (even if the hole has only the length 1)
4496 bool Interval::has_hole_between(int hole_from, int hole_to) {
4497 assert(hole_from < hole_to, "check");
4498 assert(from() <= hole_from && hole_to <= to(), "index out of interval");
4499
4500 Range* cur = _first;
4501 while (cur != Range::end()) {
4502 assert(cur->to() < cur->next()->from(), "no space between ranges");
4503
4504 // hole-range starts before this range -> hole
4505 if (hole_from < cur->from()) {
4506 return true;
4507
4508 // hole-range completely inside this range -> no hole
4509 } else if (hole_to <= cur->to()) {
4510 return false;
4511
4512 // overlapping of hole-range with this range -> hole
4513 } else if (hole_from <= cur->to()) {
4514 return true;
4515 }
4516
4517 cur = cur->next();
4518 }
4519
4520 return false;
4521 }
4522
4523
4524 #ifndef PRODUCT
4525 void Interval::print(outputStream* out) const {
4526 const char* SpillState2Name[] = { "no definition", "no spill store", "one spill store", "store at definition", "start in memory", "no optimization" };
4527 const char* UseKind2Name[] = { "N", "L", "S", "M" };
4528
4529 const char* type_name;
4530 LIR_Opr opr = LIR_OprFact::illegal();
4531 if (reg_num() < LIR_OprDesc::vreg_base) {
4532 type_name = "fixed";
4533 // need a temporary operand for fixed intervals because type() cannot be called
4534 if (assigned_reg() >= pd_first_cpu_reg && assigned_reg() <= pd_last_cpu_reg) {
4535 opr = LIR_OprFact::single_cpu(assigned_reg());
4536 } else if (assigned_reg() >= pd_first_fpu_reg && assigned_reg() <= pd_last_fpu_reg) {
4537 opr = LIR_OprFact::single_fpu(assigned_reg() - pd_first_fpu_reg);
4538 #ifdef X86
4539 } else if (assigned_reg() >= pd_first_xmm_reg && assigned_reg() <= pd_last_xmm_reg) {
4540 opr = LIR_OprFact::single_xmm(assigned_reg() - pd_first_xmm_reg);
4541 #endif
4542 } else {
4543 ShouldNotReachHere();
4544 }
4545 } else {
4546 type_name = type2name(type());
4547 if (assigned_reg() != -1 &&
4548 (LinearScan::num_physical_regs(type()) == 1 || assigned_regHi() != -1)) {
4549 opr = LinearScan::calc_operand_for_interval(this);
4550 }
4551 }
4552
4553 out->print("%d %s ", reg_num(), type_name);
4554 if (opr->is_valid()) {
4555 out->print("\"");
4556 opr->print(out);
4557 out->print("\" ");
4558 }
4559 out->print("%d %d ", split_parent()->reg_num(), (register_hint(false) != NULL ? register_hint(false)->reg_num() : -1));
4560
4561 // print ranges
4562 Range* cur = _first;
4563 while (cur != Range::end()) {
4564 cur->print(out);
4565 cur = cur->next();
4566 assert(cur != NULL, "range list not closed with range sentinel");
4567 }
4568
4569 // print use positions
4570 int prev = 0;
4571 assert(_use_pos_and_kinds.length() % 2 == 0, "must be");
4572 for (int i =_use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
4573 assert(_use_pos_and_kinds.at(i + 1) >= firstValidKind && _use_pos_and_kinds.at(i + 1) <= lastValidKind, "invalid use kind");
4574 assert(prev < _use_pos_and_kinds.at(i), "use positions not sorted");
4575
4576 out->print("%d %s ", _use_pos_and_kinds.at(i), UseKind2Name[_use_pos_and_kinds.at(i + 1)]);
4577 prev = _use_pos_and_kinds.at(i);
4578 }
4579
4580 out->print(" \"%s\"", SpillState2Name[spill_state()]);
4581 out->cr();
4582 }
4583 #endif
4584
4585
4586
4587 // **** Implementation of IntervalWalker ****************************
4588
4589 IntervalWalker::IntervalWalker(LinearScan* allocator, Interval* unhandled_fixed_first, Interval* unhandled_any_first)
4590 : _compilation(allocator->compilation())
4591 , _allocator(allocator)
4592 {
4593 _unhandled_first[fixedKind] = unhandled_fixed_first;
4594 _unhandled_first[anyKind] = unhandled_any_first;
4595 _active_first[fixedKind] = Interval::end();
4596 _inactive_first[fixedKind] = Interval::end();
4597 _active_first[anyKind] = Interval::end();
4598 _inactive_first[anyKind] = Interval::end();
4599 _current_position = -1;
4600 _current = NULL;
4601 next_interval();
4602 }
4603
4604
4605 // append interval at top of list
4606 void IntervalWalker::append_unsorted(Interval** list, Interval* interval) {
4607 interval->set_next(*list); *list = interval;
4608 }
4609
4610
4611 // append interval in order of current range from()
4612 void IntervalWalker::append_sorted(Interval** list, Interval* interval) {
4613 Interval* prev = NULL;
4614 Interval* cur = *list;
4615 while (cur->current_from() < interval->current_from()) {
4616 prev = cur; cur = cur->next();
4617 }
4618 if (prev == NULL) {
4619 *list = interval;
4620 } else {
4621 prev->set_next(interval);
4622 }
4623 interval->set_next(cur);
4624 }
4625
4626 void IntervalWalker::append_to_unhandled(Interval** list, Interval* interval) {
4627 assert(interval->from() >= current()->current_from(), "cannot append new interval before current walk position");
4628
4629 Interval* prev = NULL;
4630 Interval* cur = *list;
4631 while (cur->from() < interval->from() || (cur->from() == interval->from() && cur->first_usage(noUse) < interval->first_usage(noUse))) {
4632 prev = cur; cur = cur->next();
4633 }
4634 if (prev == NULL) {
4635 *list = interval;
4636 } else {
4637 prev->set_next(interval);
4638 }
4639 interval->set_next(cur);
4640 }
4641
4642
4643 inline bool IntervalWalker::remove_from_list(Interval** list, Interval* i) {
4644 while (*list != Interval::end() && *list != i) {
4645 list = (*list)->next_addr();
4646 }
4647 if (*list != Interval::end()) {
4648 assert(*list == i, "check");
4649 *list = (*list)->next();
4650 return true;
4651 } else {
4652 return false;
4653 }
4654 }
4655
4656 void IntervalWalker::remove_from_list(Interval* i) {
4657 bool deleted;
4658
4659 if (i->state() == activeState) {
4660 deleted = remove_from_list(active_first_addr(anyKind), i);
4661 } else {
4662 assert(i->state() == inactiveState, "invalid state");
4663 deleted = remove_from_list(inactive_first_addr(anyKind), i);
4664 }
4665
4666 assert(deleted, "interval has not been found in list");
4667 }
4668
4669
4670 void IntervalWalker::walk_to(IntervalState state, int from) {
4671 assert (state == activeState || state == inactiveState, "wrong state");
4672 for_each_interval_kind(kind) {
4673 Interval** prev = state == activeState ? active_first_addr(kind) : inactive_first_addr(kind);
4674 Interval* next = *prev;
4675 while (next->current_from() <= from) {
4676 Interval* cur = next;
4677 next = cur->next();
4678
4679 bool range_has_changed = false;
4680 while (cur->current_to() <= from) {
4681 cur->next_range();
4682 range_has_changed = true;
4683 }
4684
4685 // also handle move from inactive list to active list
4686 range_has_changed = range_has_changed || (state == inactiveState && cur->current_from() <= from);
4687
4688 if (range_has_changed) {
4689 // remove cur from list
4690 *prev = next;
4691 if (cur->current_at_end()) {
4692 // move to handled state (not maintained as a list)
4693 cur->set_state(handledState);
4694 interval_moved(cur, kind, state, handledState);
4695 } else if (cur->current_from() <= from){
4696 // sort into active list
4697 append_sorted(active_first_addr(kind), cur);
4698 cur->set_state(activeState);
4699 if (*prev == cur) {
4700 assert(state == activeState, "check");
4701 prev = cur->next_addr();
4702 }
4703 interval_moved(cur, kind, state, activeState);
4704 } else {
4705 // sort into inactive list
4706 append_sorted(inactive_first_addr(kind), cur);
4707 cur->set_state(inactiveState);
4708 if (*prev == cur) {
4709 assert(state == inactiveState, "check");
4710 prev = cur->next_addr();
4711 }
4712 interval_moved(cur, kind, state, inactiveState);
4713 }
4714 } else {
4715 prev = cur->next_addr();
4716 continue;
4717 }
4718 }
4719 }
4720 }
4721
4722
4723 void IntervalWalker::next_interval() {
4724 IntervalKind kind;
4725 Interval* any = _unhandled_first[anyKind];
4726 Interval* fixed = _unhandled_first[fixedKind];
4727
4728 if (any != Interval::end()) {
4729 // intervals may start at same position -> prefer fixed interval
4730 kind = fixed != Interval::end() && fixed->from() <= any->from() ? fixedKind : anyKind;
4731
4732 assert (kind == fixedKind && fixed->from() <= any->from() ||
4733 kind == anyKind && any->from() <= fixed->from(), "wrong interval!!!");
4734 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");
4735
4736 } else if (fixed != Interval::end()) {
4737 kind = fixedKind;
4738 } else {
4739 _current = NULL; return;
4740 }
4741 _current_kind = kind;
4742 _current = _unhandled_first[kind];
4743 _unhandled_first[kind] = _current->next();
4744 _current->set_next(Interval::end());
4745 _current->rewind_range();
4746 }
4747
4748
4749 void IntervalWalker::walk_to(int lir_op_id) {
4750 assert(_current_position <= lir_op_id, "can not walk backwards");
4751 while (current() != NULL) {
4752 bool is_active = current()->from() <= lir_op_id;
4753 int id = is_active ? current()->from() : lir_op_id;
4754
4755 TRACE_LINEAR_SCAN(2, if (_current_position < id) { tty->cr(); tty->print_cr("walk_to(%d) **************************************************************", id); })
4756
4757 // set _current_position prior to call of walk_to
4758 _current_position = id;
4759
4760 // call walk_to even if _current_position == id
4761 walk_to(activeState, id);
4762 walk_to(inactiveState, id);
4763
4764 if (is_active) {
4765 current()->set_state(activeState);
4766 if (activate_current()) {
4767 append_sorted(active_first_addr(current_kind()), current());
4768 interval_moved(current(), current_kind(), unhandledState, activeState);
4769 }
4770
4771 next_interval();
4772 } else {
4773 return;
4774 }
4775 }
4776 }
4777
4778 void IntervalWalker::interval_moved(Interval* interval, IntervalKind kind, IntervalState from, IntervalState to) {
4779 #ifndef PRODUCT
4780 if (TraceLinearScanLevel >= 4) {
4781 #define print_state(state) \
4782 switch(state) {\
4783 case unhandledState: tty->print("unhandled"); break;\
4784 case activeState: tty->print("active"); break;\
4785 case inactiveState: tty->print("inactive"); break;\
4786 case handledState: tty->print("handled"); break;\
4787 default: ShouldNotReachHere(); \
4788 }
4789
4790 print_state(from); tty->print(" to "); print_state(to);
4791 tty->fill_to(23);
4792 interval->print();
4793
4794 #undef print_state
4795 }
4796 #endif
4797 }
4798
4799
4800
4801 // **** Implementation of LinearScanWalker **************************
4802
4803 LinearScanWalker::LinearScanWalker(LinearScan* allocator, Interval* unhandled_fixed_first, Interval* unhandled_any_first)
4804 : IntervalWalker(allocator, unhandled_fixed_first, unhandled_any_first)
4805 , _move_resolver(allocator)
4806 {
4807 for (int i = 0; i < LinearScan::nof_regs; i++) {
4808 _spill_intervals[i] = new IntervalList(2);
4809 }
4810 }
4811
4812
4813 inline void LinearScanWalker::init_use_lists(bool only_process_use_pos) {
4814 for (int i = _first_reg; i <= _last_reg; i++) {
4815 _use_pos[i] = max_jint;
4816
4817 if (!only_process_use_pos) {
4818 _block_pos[i] = max_jint;
4819 _spill_intervals[i]->clear();
4820 }
4821 }
4822 }
4823
4824 inline void LinearScanWalker::exclude_from_use(int reg) {
4825 assert(reg < LinearScan::nof_regs, "interval must have a register assigned (stack slots not allowed)");
4826 if (reg >= _first_reg && reg <= _last_reg) {
4827 _use_pos[reg] = 0;
4828 }
4829 }
4830 inline void LinearScanWalker::exclude_from_use(Interval* i) {
4831 assert(i->assigned_reg() != any_reg, "interval has no register assigned");
4832
4833 exclude_from_use(i->assigned_reg());
4834 exclude_from_use(i->assigned_regHi());
4835 }
4836
4837 inline void LinearScanWalker::set_use_pos(int reg, Interval* i, int use_pos, bool only_process_use_pos) {
4838 assert(use_pos != 0, "must use exclude_from_use to set use_pos to 0");
4839
4840 if (reg >= _first_reg && reg <= _last_reg) {
4841 if (_use_pos[reg] > use_pos) {
4842 _use_pos[reg] = use_pos;
4843 }
4844 if (!only_process_use_pos) {
4845 _spill_intervals[reg]->append(i);
4846 }
4847 }
4848 }
4849 inline void LinearScanWalker::set_use_pos(Interval* i, int use_pos, bool only_process_use_pos) {
4850 assert(i->assigned_reg() != any_reg, "interval has no register assigned");
4851 if (use_pos != -1) {
4852 set_use_pos(i->assigned_reg(), i, use_pos, only_process_use_pos);
4853 set_use_pos(i->assigned_regHi(), i, use_pos, only_process_use_pos);
4854 }
4855 }
4856
4857 inline void LinearScanWalker::set_block_pos(int reg, Interval* i, int block_pos) {
4858 if (reg >= _first_reg && reg <= _last_reg) {
4859 if (_block_pos[reg] > block_pos) {
4860 _block_pos[reg] = block_pos;
4861 }
4862 if (_use_pos[reg] > block_pos) {
4863 _use_pos[reg] = block_pos;
4864 }
4865 }
4866 }
4867 inline void LinearScanWalker::set_block_pos(Interval* i, int block_pos) {
4868 assert(i->assigned_reg() != any_reg, "interval has no register assigned");
4869 if (block_pos != -1) {
4870 set_block_pos(i->assigned_reg(), i, block_pos);
4871 set_block_pos(i->assigned_regHi(), i, block_pos);
4872 }
4873 }
4874
4875
4876 void LinearScanWalker::free_exclude_active_fixed() {
4877 Interval* list = active_first(fixedKind);
4878 while (list != Interval::end()) {
4879 assert(list->assigned_reg() < LinearScan::nof_regs, "active interval must have a register assigned");
4880 exclude_from_use(list);
4881 list = list->next();
4882 }
4883 }
4884
4885 void LinearScanWalker::free_exclude_active_any() {
4886 Interval* list = active_first(anyKind);
4887 while (list != Interval::end()) {
4888 exclude_from_use(list);
4889 list = list->next();
4890 }
4891 }
4892
4893 void LinearScanWalker::free_collect_inactive_fixed(Interval* cur) {
4894 Interval* list = inactive_first(fixedKind);
4895 while (list != Interval::end()) {
4896 if (cur->to() <= list->current_from()) {
4897 assert(list->current_intersects_at(cur) == -1, "must not intersect");
4898 set_use_pos(list, list->current_from(), true);
4899 } else {
4900 set_use_pos(list, list->current_intersects_at(cur), true);
4901 }
4902 list = list->next();
4903 }
4904 }
4905
4906 void LinearScanWalker::free_collect_inactive_any(Interval* cur) {
4907 Interval* list = inactive_first(anyKind);
4908 while (list != Interval::end()) {
4909 set_use_pos(list, list->current_intersects_at(cur), true);
4910 list = list->next();
4911 }
4912 }
4913
4914 void LinearScanWalker::free_collect_unhandled(IntervalKind kind, Interval* cur) {
4915 Interval* list = unhandled_first(kind);
4916 while (list != Interval::end()) {
4917 set_use_pos(list, list->intersects_at(cur), true);
4918 if (kind == fixedKind && cur->to() <= list->from()) {
4919 set_use_pos(list, list->from(), true);
4920 }
4921 list = list->next();
4922 }
4923 }
4924
4925 void LinearScanWalker::spill_exclude_active_fixed() {
4926 Interval* list = active_first(fixedKind);
4927 while (list != Interval::end()) {
4928 exclude_from_use(list);
4929 list = list->next();
4930 }
4931 }
4932
4933 void LinearScanWalker::spill_block_unhandled_fixed(Interval* cur) {
4934 Interval* list = unhandled_first(fixedKind);
4935 while (list != Interval::end()) {
4936 set_block_pos(list, list->intersects_at(cur));
4937 list = list->next();
4938 }
4939 }
4940
4941 void LinearScanWalker::spill_block_inactive_fixed(Interval* cur) {
4942 Interval* list = inactive_first(fixedKind);
4943 while (list != Interval::end()) {
4944 if (cur->to() > list->current_from()) {
4945 set_block_pos(list, list->current_intersects_at(cur));
4946 } else {
4947 assert(list->current_intersects_at(cur) == -1, "invalid optimization: intervals intersect");
4948 }
4949
4950 list = list->next();
4951 }
4952 }
4953
4954 void LinearScanWalker::spill_collect_active_any() {
4955 Interval* list = active_first(anyKind);
4956 while (list != Interval::end()) {
4957 set_use_pos(list, MIN2(list->next_usage(loopEndMarker, _current_position), list->to()), false);
4958 list = list->next();
4959 }
4960 }
4961
4962 void LinearScanWalker::spill_collect_inactive_any(Interval* cur) {
4963 Interval* list = inactive_first(anyKind);
4964 while (list != Interval::end()) {
4965 if (list->current_intersects(cur)) {
4966 set_use_pos(list, MIN2(list->next_usage(loopEndMarker, _current_position), list->to()), false);
4967 }
4968 list = list->next();
4969 }
4970 }
4971
4972
4973 void LinearScanWalker::insert_move(int op_id, Interval* src_it, Interval* dst_it) {
4974 // output all moves here. When source and target are equal, the move is
4975 // optimized away later in assign_reg_nums
4976
4977 op_id = (op_id + 1) & ~1;
4978 BlockBegin* op_block = allocator()->block_of_op_with_id(op_id);
4979 assert(op_id > 0 && allocator()->block_of_op_with_id(op_id - 2) == op_block, "cannot insert move at block boundary");
4980
4981 // calculate index of instruction inside instruction list of current block
4982 // the minimal index (for a block with no spill moves) can be calculated because the
4983 // numbering of instructions is known.
4984 // When the block already contains spill moves, the index must be increased until the
4985 // correct index is reached.
4986 LIR_OpList* list = op_block->lir()->instructions_list();
4987 int index = (op_id - list->at(0)->id()) / 2;
4988 assert(list->at(index)->id() <= op_id, "error in calculation");
4989
4990 while (list->at(index)->id() != op_id) {
4991 index++;
4992 assert(0 <= index && index < list->length(), "index out of bounds");
4993 }
4994 assert(1 <= index && index < list->length(), "index out of bounds");
4995 assert(list->at(index)->id() == op_id, "error in calculation");
4996
4997 // insert new instruction before instruction at position index
4998 _move_resolver.move_insert_position(op_block->lir(), index - 1);
4999 _move_resolver.add_mapping(src_it, dst_it);
5000 }
5001
5002
5003 int LinearScanWalker::find_optimal_split_pos(BlockBegin* min_block, BlockBegin* max_block, int max_split_pos) {
5004 int from_block_nr = min_block->linear_scan_number();
5005 int to_block_nr = max_block->linear_scan_number();
5006
5007 assert(0 <= from_block_nr && from_block_nr < block_count(), "out of range");
5008 assert(0 <= to_block_nr && to_block_nr < block_count(), "out of range");
5009 assert(from_block_nr < to_block_nr, "must cross block boundary");
5010
5011 // Try to split at end of max_block. If this would be after
5012 // max_split_pos, then use the begin of max_block
5013 int optimal_split_pos = max_block->last_lir_instruction_id() + 2;
5014 if (optimal_split_pos > max_split_pos) {
5015 optimal_split_pos = max_block->first_lir_instruction_id();
5016 }
5017
5018 int min_loop_depth = max_block->loop_depth();
5019 for (int i = to_block_nr - 1; i >= from_block_nr; i--) {
5020 BlockBegin* cur = block_at(i);
5021
5022 if (cur->loop_depth() < min_loop_depth) {
5023 // block with lower loop-depth found -> split at the end of this block
5024 min_loop_depth = cur->loop_depth();
5025 optimal_split_pos = cur->last_lir_instruction_id() + 2;
5026 }
5027 }
5028 assert(optimal_split_pos > allocator()->max_lir_op_id() || allocator()->is_block_begin(optimal_split_pos), "algorithm must move split pos to block boundary");
5029
5030 return optimal_split_pos;
5031 }
5032
5033
5034 int LinearScanWalker::find_optimal_split_pos(Interval* it, int min_split_pos, int max_split_pos, bool do_loop_optimization) {
5035 int optimal_split_pos = -1;
5036 if (min_split_pos == max_split_pos) {
5037 // trivial case, no optimization of split position possible
5038 TRACE_LINEAR_SCAN(4, tty->print_cr(" min-pos and max-pos are equal, no optimization possible"));
5039 optimal_split_pos = min_split_pos;
5040
5041 } else {
5042 assert(min_split_pos < max_split_pos, "must be true then");
5043 assert(min_split_pos > 0, "cannot access min_split_pos - 1 otherwise");
5044
5045 // reason for using min_split_pos - 1: when the minimal split pos is exactly at the
5046 // beginning of a block, then min_split_pos is also a possible split position.
5047 // Use the block before as min_block, because then min_block->last_lir_instruction_id() + 2 == min_split_pos
5048 BlockBegin* min_block = allocator()->block_of_op_with_id(min_split_pos - 1);
5049
5050 // reason for using max_split_pos - 1: otherwise there would be an assertion failure
5051 // when an interval ends at the end of the last block of the method
5052 // (in this case, max_split_pos == allocator()->max_lir_op_id() + 2, and there is no
5053 // block at this op_id)
5054 BlockBegin* max_block = allocator()->block_of_op_with_id(max_split_pos - 1);
5055
5056 assert(min_block->linear_scan_number() <= max_block->linear_scan_number(), "invalid order");
5057 if (min_block == max_block) {
5058 // split position cannot be moved to block boundary, so split as late as possible
5059 TRACE_LINEAR_SCAN(4, tty->print_cr(" cannot move split pos to block boundary because min_pos and max_pos are in same block"));
5060 optimal_split_pos = max_split_pos;
5061
5062 } else if (it->has_hole_between(max_split_pos - 1, max_split_pos) && !allocator()->is_block_begin(max_split_pos)) {
5063 // Do not move split position if the interval has a hole before max_split_pos.
5064 // Intervals resulting from Phi-Functions have more than one definition (marked
5065 // as mustHaveRegister) with a hole before each definition. When the register is needed
5066 // for the second definition, an earlier reloading is unnecessary.
5067 TRACE_LINEAR_SCAN(4, tty->print_cr(" interval has hole just before max_split_pos, so splitting at max_split_pos"));
5068 optimal_split_pos = max_split_pos;
5069
5070 } else {
5071 // seach optimal block boundary between min_split_pos and max_split_pos
5072 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()));
5073
5074 if (do_loop_optimization) {
5075 // Loop optimization: if a loop-end marker is found between min- and max-position,
5076 // then split before this loop
5077 int loop_end_pos = it->next_usage_exact(loopEndMarker, min_block->last_lir_instruction_id() + 2);
5078 TRACE_LINEAR_SCAN(4, tty->print_cr(" loop optimization: loop end found at pos %d", loop_end_pos));
5079
5080 assert(loop_end_pos > min_split_pos, "invalid order");
5081 if (loop_end_pos < max_split_pos) {
5082 // loop-end marker found between min- and max-position
5083 // if it is not the end marker for the same loop as the min-position, then move
5084 // the max-position to this loop block.
5085 // Desired result: uses tagged as shouldHaveRegister inside a loop cause a reloading
5086 // of the interval (normally, only mustHaveRegister causes a reloading)
5087 BlockBegin* loop_block = allocator()->block_of_op_with_id(loop_end_pos);
5088
5089 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()));
5090 assert(loop_block != min_block, "loop_block and min_block must be different because block boundary is needed between");
5091
5092 optimal_split_pos = find_optimal_split_pos(min_block, loop_block, loop_block->last_lir_instruction_id() + 2);
5093 if (optimal_split_pos == loop_block->last_lir_instruction_id() + 2) {
5094 optimal_split_pos = -1;
5095 TRACE_LINEAR_SCAN(4, tty->print_cr(" loop optimization not necessary"));
5096 } else {
5097 TRACE_LINEAR_SCAN(4, tty->print_cr(" loop optimization successful"));
5098 }
5099 }
5100 }
5101
5102 if (optimal_split_pos == -1) {
5103 // not calculated by loop optimization
5104 optimal_split_pos = find_optimal_split_pos(min_block, max_block, max_split_pos);
5105 }
5106 }
5107 }
5108 TRACE_LINEAR_SCAN(4, tty->print_cr(" optimal split position: %d", optimal_split_pos));
5109
5110 return optimal_split_pos;
5111 }
5112
5113
5114 /*
5115 split an interval at the optimal position between min_split_pos and
5116 max_split_pos in two parts:
5117 1) the left part has already a location assigned
5118 2) the right part is sorted into to the unhandled-list
5119 */
5120 void LinearScanWalker::split_before_usage(Interval* it, int min_split_pos, int max_split_pos) {
5121 TRACE_LINEAR_SCAN(2, tty->print ("----- splitting interval: "); it->print());
5122 TRACE_LINEAR_SCAN(2, tty->print_cr(" between %d and %d", min_split_pos, max_split_pos));
5123
5124 assert(it->from() < min_split_pos, "cannot split at start of interval");
5125 assert(current_position() < min_split_pos, "cannot split before current position");
5126 assert(min_split_pos <= max_split_pos, "invalid order");
5127 assert(max_split_pos <= it->to(), "cannot split after end of interval");
5128
5129 int optimal_split_pos = find_optimal_split_pos(it, min_split_pos, max_split_pos, true);
5130
5131 assert(min_split_pos <= optimal_split_pos && optimal_split_pos <= max_split_pos, "out of range");
5132 assert(optimal_split_pos <= it->to(), "cannot split after end of interval");
5133 assert(optimal_split_pos > it->from(), "cannot split at start of interval");
5134
5135 if (optimal_split_pos == it->to() && it->next_usage(mustHaveRegister, min_split_pos) == max_jint) {
5136 // the split position would be just before the end of the interval
5137 // -> no split at all necessary
5138 TRACE_LINEAR_SCAN(4, tty->print_cr(" no split necessary because optimal split position is at end of interval"));
5139 return;
5140 }
5141
5142 // must calculate this before the actual split is performed and before split position is moved to odd op_id
5143 bool move_necessary = !allocator()->is_block_begin(optimal_split_pos) && !it->has_hole_between(optimal_split_pos - 1, optimal_split_pos);
5144
5145 if (!allocator()->is_block_begin(optimal_split_pos)) {
5146 // move position before actual instruction (odd op_id)
5147 optimal_split_pos = (optimal_split_pos - 1) | 1;
5148 }
5149
5150 TRACE_LINEAR_SCAN(4, tty->print_cr(" splitting at position %d", optimal_split_pos));
5151 assert(allocator()->is_block_begin(optimal_split_pos) || (optimal_split_pos % 2 == 1), "split pos must be odd when not on block boundary");
5152 assert(!allocator()->is_block_begin(optimal_split_pos) || (optimal_split_pos % 2 == 0), "split pos must be even on block boundary");
5153
5154 Interval* split_part = it->split(optimal_split_pos);
5155
5156 allocator()->append_interval(split_part);
5157 allocator()->copy_register_flags(it, split_part);
5158 split_part->set_insert_move_when_activated(move_necessary);
5159 append_to_unhandled(unhandled_first_addr(anyKind), split_part);
5160
5161 TRACE_LINEAR_SCAN(2, tty->print_cr(" split interval in two parts (insert_move_when_activated: %d)", move_necessary));
5162 TRACE_LINEAR_SCAN(2, tty->print (" "); it->print());
5163 TRACE_LINEAR_SCAN(2, tty->print (" "); split_part->print());
5164 }
5165
5166 /*
5167 split an interval at the optimal position between min_split_pos and
5168 max_split_pos in two parts:
5169 1) the left part has already a location assigned
5170 2) the right part is always on the stack and therefore ignored in further processing
5171 */
5172 void LinearScanWalker::split_for_spilling(Interval* it) {
5173 // calculate allowed range of splitting position
5174 int max_split_pos = current_position();
5175 int min_split_pos = MAX2(it->previous_usage(shouldHaveRegister, max_split_pos) + 1, it->from());
5176
5177 TRACE_LINEAR_SCAN(2, tty->print ("----- splitting and spilling interval: "); it->print());
5178 TRACE_LINEAR_SCAN(2, tty->print_cr(" between %d and %d", min_split_pos, max_split_pos));
5179
5180 assert(it->state() == activeState, "why spill interval that is not active?");
5181 assert(it->from() <= min_split_pos, "cannot split before start of interval");
5182 assert(min_split_pos <= max_split_pos, "invalid order");
5183 assert(max_split_pos < it->to(), "cannot split at end end of interval");
5184 assert(current_position() < it->to(), "interval must not end before current position");
5185
5186 if (min_split_pos == it->from()) {
5187 // the whole interval is never used, so spill it entirely to memory
5188 TRACE_LINEAR_SCAN(2, tty->print_cr(" spilling entire interval because split pos is at beginning of interval"));
5189 assert(it->first_usage(shouldHaveRegister) > current_position(), "interval must not have use position before current_position");
5190
5191 allocator()->assign_spill_slot(it);
5192 allocator()->change_spill_state(it, min_split_pos);
5193
5194 // Also kick parent intervals out of register to memory when they have no use
5195 // position. This avoids short interval in register surrounded by intervals in
5196 // memory -> avoid useless moves from memory to register and back
5197 Interval* parent = it;
5198 while (parent != NULL && parent->is_split_child()) {
5199 parent = parent->split_child_before_op_id(parent->from());
5200
5201 if (parent->assigned_reg() < LinearScan::nof_regs) {
5202 if (parent->first_usage(shouldHaveRegister) == max_jint) {
5203 // parent is never used, so kick it out of its assigned register
5204 TRACE_LINEAR_SCAN(4, tty->print_cr(" kicking out interval %d out of its register because it is never used", parent->reg_num()));
5205 allocator()->assign_spill_slot(parent);
5206 } else {
5207 // do not go further back because the register is actually used by the interval
5208 parent = NULL;
5209 }
5210 }
5211 }
5212
5213 } else {
5214 // search optimal split pos, split interval and spill only the right hand part
5215 int optimal_split_pos = find_optimal_split_pos(it, min_split_pos, max_split_pos, false);
5216
5217 assert(min_split_pos <= optimal_split_pos && optimal_split_pos <= max_split_pos, "out of range");
5218 assert(optimal_split_pos < it->to(), "cannot split at end of interval");
5219 assert(optimal_split_pos >= it->from(), "cannot split before start of interval");
5220
5221 if (!allocator()->is_block_begin(optimal_split_pos)) {
5222 // move position before actual instruction (odd op_id)
5223 optimal_split_pos = (optimal_split_pos - 1) | 1;
5224 }
5225
5226 TRACE_LINEAR_SCAN(4, tty->print_cr(" splitting at position %d", optimal_split_pos));
5227 assert(allocator()->is_block_begin(optimal_split_pos) || (optimal_split_pos % 2 == 1), "split pos must be odd when not on block boundary");
5228 assert(!allocator()->is_block_begin(optimal_split_pos) || (optimal_split_pos % 2 == 0), "split pos must be even on block boundary");
5229
5230 Interval* spilled_part = it->split(optimal_split_pos);
5231 allocator()->append_interval(spilled_part);
5232 allocator()->assign_spill_slot(spilled_part);
5233 allocator()->change_spill_state(spilled_part, optimal_split_pos);
5234
5235 if (!allocator()->is_block_begin(optimal_split_pos)) {
5236 TRACE_LINEAR_SCAN(4, tty->print_cr(" inserting move from interval %d to %d", it->reg_num(), spilled_part->reg_num()));
5237 insert_move(optimal_split_pos, it, spilled_part);
5238 }
5239
5240 // the current_split_child is needed later when moves are inserted for reloading
5241 assert(spilled_part->current_split_child() == it, "overwriting wrong current_split_child");
5242 spilled_part->make_current_split_child();
5243
5244 TRACE_LINEAR_SCAN(2, tty->print_cr(" split interval in two parts"));
5245 TRACE_LINEAR_SCAN(2, tty->print (" "); it->print());
5246 TRACE_LINEAR_SCAN(2, tty->print (" "); spilled_part->print());
5247 }
5248 }
5249
5250
5251 void LinearScanWalker::split_stack_interval(Interval* it) {
5252 int min_split_pos = current_position() + 1;
5253 int max_split_pos = MIN2(it->first_usage(shouldHaveRegister), it->to());
5254
5255 split_before_usage(it, min_split_pos, max_split_pos);
5256 }
5257
5258 void LinearScanWalker::split_when_partial_register_available(Interval* it, int register_available_until) {
5259 int min_split_pos = MAX2(it->previous_usage(shouldHaveRegister, register_available_until), it->from() + 1);
5260 int max_split_pos = register_available_until;
5261
5262 split_before_usage(it, min_split_pos, max_split_pos);
5263 }
5264
5265 void LinearScanWalker::split_and_spill_interval(Interval* it) {
5266 assert(it->state() == activeState || it->state() == inactiveState, "other states not allowed");
5267
5268 int current_pos = current_position();
5269 if (it->state() == inactiveState) {
5270 // the interval is currently inactive, so no spill slot is needed for now.
5271 // when the split part is activated, the interval has a new chance to get a register,
5272 // so in the best case no stack slot is necessary
5273 assert(it->has_hole_between(current_pos - 1, current_pos + 1), "interval can not be inactive otherwise");
5274 split_before_usage(it, current_pos + 1, current_pos + 1);
5275
5276 } else {
5277 // search the position where the interval must have a register and split
5278 // at the optimal position before.
5279 // The new created part is added to the unhandled list and will get a register
5280 // when it is activated
5281 int min_split_pos = current_pos + 1;
5282 int max_split_pos = MIN2(it->next_usage(mustHaveRegister, min_split_pos), it->to());
5283
5284 split_before_usage(it, min_split_pos, max_split_pos);
5285
5286 assert(it->next_usage(mustHaveRegister, current_pos) == max_jint, "the remaining part is spilled to stack and therefore has no register");
5287 split_for_spilling(it);
5288 }
5289 }
5290
5291
5292 int LinearScanWalker::find_free_reg(int reg_needed_until, int interval_to, int hint_reg, int ignore_reg, bool* need_split) {
5293 int min_full_reg = any_reg;
5294 int max_partial_reg = any_reg;
5295
5296 for (int i = _first_reg; i <= _last_reg; i++) {
5297 if (i == ignore_reg) {
5298 // this register must be ignored
5299
5300 } else if (_use_pos[i] >= interval_to) {
5301 // this register is free for the full interval
5302 if (min_full_reg == any_reg || i == hint_reg || (_use_pos[i] < _use_pos[min_full_reg] && min_full_reg != hint_reg)) {
5303 min_full_reg = i;
5304 }
5305 } else if (_use_pos[i] > reg_needed_until) {
5306 // this register is at least free until reg_needed_until
5307 if (max_partial_reg == any_reg || i == hint_reg || (_use_pos[i] > _use_pos[max_partial_reg] && max_partial_reg != hint_reg)) {
5308 max_partial_reg = i;
5309 }
5310 }
5311 }
5312
5313 if (min_full_reg != any_reg) {
5314 return min_full_reg;
5315 } else if (max_partial_reg != any_reg) {
5316 *need_split = true;
5317 return max_partial_reg;
5318 } else {
5319 return any_reg;
5320 }
5321 }
5322
5323 int LinearScanWalker::find_free_double_reg(int reg_needed_until, int interval_to, int hint_reg, bool* need_split) {
5324 assert((_last_reg - _first_reg + 1) % 2 == 0, "adjust algorithm");
5325
5326 int min_full_reg = any_reg;
5327 int max_partial_reg = any_reg;
5328
5329 for (int i = _first_reg; i < _last_reg; i+=2) {
5330 if (_use_pos[i] >= interval_to && _use_pos[i + 1] >= interval_to) {
5331 // this register is free for the full interval
5332 if (min_full_reg == any_reg || i == hint_reg || (_use_pos[i] < _use_pos[min_full_reg] && min_full_reg != hint_reg)) {
5333 min_full_reg = i;
5334 }
5335 } else if (_use_pos[i] > reg_needed_until && _use_pos[i + 1] > reg_needed_until) {
5336 // this register is at least free until reg_needed_until
5337 if (max_partial_reg == any_reg || i == hint_reg || (_use_pos[i] > _use_pos[max_partial_reg] && max_partial_reg != hint_reg)) {
5338 max_partial_reg = i;
5339 }
5340 }
5341 }
5342
5343 if (min_full_reg != any_reg) {
5344 return min_full_reg;
5345 } else if (max_partial_reg != any_reg) {
5346 *need_split = true;
5347 return max_partial_reg;
5348 } else {
5349 return any_reg;
5350 }
5351 }
5352
5353
5354 bool LinearScanWalker::alloc_free_reg(Interval* cur) {
5355 TRACE_LINEAR_SCAN(2, tty->print("trying to find free register for "); cur->print());
5356
5357 init_use_lists(true);
5358 free_exclude_active_fixed();
5359 free_exclude_active_any();
5360 free_collect_inactive_fixed(cur);
5361 free_collect_inactive_any(cur);
5362 // free_collect_unhandled(fixedKind, cur);
5363 assert(unhandled_first(fixedKind) == Interval::end(), "must not have unhandled fixed intervals because all fixed intervals have a use at position 0");
5364
5365 // _use_pos contains the start of the next interval that has this register assigned
5366 // (either as a fixed register or a normal allocated register in the past)
5367 // only intervals overlapping with cur are processed, non-overlapping invervals can be ignored safely
5368 TRACE_LINEAR_SCAN(4, tty->print_cr(" state of registers:"));
5369 TRACE_LINEAR_SCAN(4, for (int i = _first_reg; i <= _last_reg; i++) tty->print_cr(" reg %d: use_pos: %d", i, _use_pos[i]));
5370
5371 int hint_reg, hint_regHi;
5372 Interval* register_hint = cur->register_hint();
5373 if (register_hint != NULL) {
5374 hint_reg = register_hint->assigned_reg();
5375 hint_regHi = register_hint->assigned_regHi();
5376
5377 if (allocator()->is_precolored_cpu_interval(register_hint)) {
5378 assert(hint_reg != any_reg && hint_regHi == any_reg, "must be for fixed intervals");
5379 hint_regHi = hint_reg + 1; // connect e.g. eax-edx
5380 }
5381 TRACE_LINEAR_SCAN(4, tty->print(" hint registers %d, %d from interval ", hint_reg, hint_regHi); register_hint->print());
5382
5383 } else {
5384 hint_reg = any_reg;
5385 hint_regHi = any_reg;
5386 }
5387 assert(hint_reg == any_reg || hint_reg != hint_regHi, "hint reg and regHi equal");
5388 assert(cur->assigned_reg() == any_reg && cur->assigned_regHi() == any_reg, "register already assigned to interval");
5389
5390 // the register must be free at least until this position
5391 int reg_needed_until = cur->from() + 1;
5392 int interval_to = cur->to();
5393
5394 bool need_split = false;
5395 int split_pos = -1;
5396 int reg = any_reg;
5397 int regHi = any_reg;
5398
5399 if (_adjacent_regs) {
5400 reg = find_free_double_reg(reg_needed_until, interval_to, hint_reg, &need_split);
5401 regHi = reg + 1;
5402 if (reg == any_reg) {
5403 return false;
5404 }
5405 split_pos = MIN2(_use_pos[reg], _use_pos[regHi]);
5406
5407 } else {
5408 reg = find_free_reg(reg_needed_until, interval_to, hint_reg, any_reg, &need_split);
5409 if (reg == any_reg) {
5410 return false;
5411 }
5412 split_pos = _use_pos[reg];
5413
5414 if (_num_phys_regs == 2) {
5415 regHi = find_free_reg(reg_needed_until, interval_to, hint_regHi, reg, &need_split);
5416
5417 if (_use_pos[reg] < interval_to && regHi == any_reg) {
5418 // do not split interval if only one register can be assigned until the split pos
5419 // (when one register is found for the whole interval, split&spill is only
5420 // performed for the hi register)
5421 return false;
5422
5423 } else if (regHi != any_reg) {
5424 split_pos = MIN2(split_pos, _use_pos[regHi]);
5425
5426 // sort register numbers to prevent e.g. a move from eax,ebx to ebx,eax
5427 if (reg > regHi) {
5428 int temp = reg;
5429 reg = regHi;
5430 regHi = temp;
5431 }
5432 }
5433 }
5434 }
5435
5436 cur->assign_reg(reg, regHi);
5437 TRACE_LINEAR_SCAN(2, tty->print_cr("selected register %d, %d", reg, regHi));
5438
5439 assert(split_pos > 0, "invalid split_pos");
5440 if (need_split) {
5441 // register not available for full interval, so split it
5442 split_when_partial_register_available(cur, split_pos);
5443 }
5444
5445 // only return true if interval is completely assigned
5446 return _num_phys_regs == 1 || regHi != any_reg;
5447 }
5448
5449
5450 int LinearScanWalker::find_locked_reg(int reg_needed_until, int interval_to, int hint_reg, int ignore_reg, bool* need_split) {
5451 int max_reg = any_reg;
5452
5453 for (int i = _first_reg; i <= _last_reg; i++) {
5454 if (i == ignore_reg) {
5455 // this register must be ignored
5456
5457 } else if (_use_pos[i] > reg_needed_until) {
5458 if (max_reg == any_reg || i == hint_reg || (_use_pos[i] > _use_pos[max_reg] && max_reg != hint_reg)) {
5459 max_reg = i;
5460 }
5461 }
5462 }
5463
5464 if (max_reg != any_reg && _block_pos[max_reg] <= interval_to) {
5465 *need_split = true;
5466 }
5467
5468 return max_reg;
5469 }
5470
5471 int LinearScanWalker::find_locked_double_reg(int reg_needed_until, int interval_to, int hint_reg, bool* need_split) {
5472 assert((_last_reg - _first_reg + 1) % 2 == 0, "adjust algorithm");
5473
5474 int max_reg = any_reg;
5475
5476 for (int i = _first_reg; i < _last_reg; i+=2) {
5477 if (_use_pos[i] > reg_needed_until && _use_pos[i + 1] > reg_needed_until) {
5478 if (max_reg == any_reg || _use_pos[i] > _use_pos[max_reg]) {
5479 max_reg = i;
5480 }
5481 }
5482 }
5483
5484 if (_block_pos[max_reg] <= interval_to || _block_pos[max_reg + 1] <= interval_to) {
5485 *need_split = true;
5486 }
5487
5488 return max_reg;
5489 }
5490
5491 void LinearScanWalker::split_and_spill_intersecting_intervals(int reg, int regHi) {
5492 assert(reg != any_reg, "no register assigned");
5493
5494 for (int i = 0; i < _spill_intervals[reg]->length(); i++) {
5495 Interval* it = _spill_intervals[reg]->at(i);
5496 remove_from_list(it);
5497 split_and_spill_interval(it);
5498 }
5499
5500 if (regHi != any_reg) {
5501 IntervalList* processed = _spill_intervals[reg];
5502 for (int i = 0; i < _spill_intervals[regHi]->length(); i++) {
5503 Interval* it = _spill_intervals[regHi]->at(i);
5504 if (processed->index_of(it) == -1) {
5505 remove_from_list(it);
5506 split_and_spill_interval(it);
5507 }
5508 }
5509 }
5510 }
5511
5512
5513 // Split an Interval and spill it to memory so that cur can be placed in a register
5514 void LinearScanWalker::alloc_locked_reg(Interval* cur) {
5515 TRACE_LINEAR_SCAN(2, tty->print("need to split and spill to get register for "); cur->print());
5516
5517 // collect current usage of registers
5518 init_use_lists(false);
5519 spill_exclude_active_fixed();
5520 // spill_block_unhandled_fixed(cur);
5521 assert(unhandled_first(fixedKind) == Interval::end(), "must not have unhandled fixed intervals because all fixed intervals have a use at position 0");
5522 spill_block_inactive_fixed(cur);
5523 spill_collect_active_any();
5524 spill_collect_inactive_any(cur);
5525
5526 #ifndef PRODUCT
5527 if (TraceLinearScanLevel >= 4) {
5528 tty->print_cr(" state of registers:");
5529 for (int i = _first_reg; i <= _last_reg; i++) {
5530 tty->print(" reg %d: use_pos: %d, block_pos: %d, intervals: ", i, _use_pos[i], _block_pos[i]);
5531 for (int j = 0; j < _spill_intervals[i]->length(); j++) {
5532 tty->print("%d ", _spill_intervals[i]->at(j)->reg_num());
5533 }
5534 tty->cr();
5535 }
5536 }
5537 #endif
5538
5539 // the register must be free at least until this position
5540 int reg_needed_until = MIN2(cur->first_usage(mustHaveRegister), cur->from() + 1);
5541 int interval_to = cur->to();
5542 assert (reg_needed_until > 0 && reg_needed_until < max_jint, "interval has no use");
5543
5544 int split_pos = 0;
5545 int use_pos = 0;
5546 bool need_split = false;
5547 int reg, regHi;
5548
5549 if (_adjacent_regs) {
5550 reg = find_locked_double_reg(reg_needed_until, interval_to, any_reg, &need_split);
5551 regHi = reg + 1;
5552
5553 if (reg != any_reg) {
5554 use_pos = MIN2(_use_pos[reg], _use_pos[regHi]);
5555 split_pos = MIN2(_block_pos[reg], _block_pos[regHi]);
5556 }
5557 } else {
5558 reg = find_locked_reg(reg_needed_until, interval_to, any_reg, cur->assigned_reg(), &need_split);
5559 regHi = any_reg;
5560
5561 if (reg != any_reg) {
5562 use_pos = _use_pos[reg];
5563 split_pos = _block_pos[reg];
5564
5565 if (_num_phys_regs == 2) {
5566 if (cur->assigned_reg() != any_reg) {
5567 regHi = reg;
5568 reg = cur->assigned_reg();
5569 } else {
5570 regHi = find_locked_reg(reg_needed_until, interval_to, any_reg, reg, &need_split);
5571 if (regHi != any_reg) {
5572 use_pos = MIN2(use_pos, _use_pos[regHi]);
5573 split_pos = MIN2(split_pos, _block_pos[regHi]);
5574 }
5575 }
5576
5577 if (regHi != any_reg && reg > regHi) {
5578 // sort register numbers to prevent e.g. a move from eax,ebx to ebx,eax
5579 int temp = reg;
5580 reg = regHi;
5581 regHi = temp;
5582 }
5583 }
5584 }
5585 }
5586
5587 if (reg == any_reg || (_num_phys_regs == 2 && regHi == any_reg) || use_pos <= cur->first_usage(mustHaveRegister)) {
5588 // the first use of cur is later than the spilling position -> spill cur
5589 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));
5590
5591 if (cur->first_usage(mustHaveRegister) <= cur->from() + 1) {
5592 assert(false, "cannot spill interval that is used in first instruction (possible reason: no register found)");
5593 // assign a reasonable register and do a bailout in product mode to avoid errors
5594 allocator()->assign_spill_slot(cur);
5595 BAILOUT("LinearScan: no register found");
5596 }
5597
5598 split_and_spill_interval(cur);
5599 } else {
5600 TRACE_LINEAR_SCAN(4, tty->print_cr("decided to use register %d, %d", reg, regHi));
5601 assert(reg != any_reg && (_num_phys_regs == 1 || regHi != any_reg), "no register found");
5602 assert(split_pos > 0, "invalid split_pos");
5603 assert(need_split == false || split_pos > cur->from(), "splitting interval at from");
5604
5605 cur->assign_reg(reg, regHi);
5606 if (need_split) {
5607 // register not available for full interval, so split it
5608 split_when_partial_register_available(cur, split_pos);
5609 }
5610
5611 // perform splitting and spilling for all affected intervalls
5612 split_and_spill_intersecting_intervals(reg, regHi);
5613 }
5614 }
5615
5616 bool LinearScanWalker::no_allocation_possible(Interval* cur) {
5617 #ifdef X86
5618 // fast calculation of intervals that can never get a register because the
5619 // the next instruction is a call that blocks all registers
5620 // Note: this does not work if callee-saved registers are available (e.g. on Sparc)
5621
5622 // check if this interval is the result of a split operation
5623 // (an interval got a register until this position)
5624 int pos = cur->from();
5625 if ((pos & 1) == 1) {
5626 // the current instruction is a call that blocks all registers
5627 if (pos < allocator()->max_lir_op_id() && allocator()->has_call(pos + 1)) {
5628 TRACE_LINEAR_SCAN(4, tty->print_cr(" free register cannot be available because all registers blocked by following call"));
5629
5630 // safety check that there is really no register available
5631 assert(alloc_free_reg(cur) == false, "found a register for this interval");
5632 return true;
5633 }
5634
5635 }
5636 #endif
5637 return false;
5638 }
5639
5640 void LinearScanWalker::init_vars_for_alloc(Interval* cur) {
5641 BasicType type = cur->type();
5642 _num_phys_regs = LinearScan::num_physical_regs(type);
5643 _adjacent_regs = LinearScan::requires_adjacent_regs(type);
5644
5645 if (pd_init_regs_for_alloc(cur)) {
5646 // the appropriate register range was selected.
5647 } else if (type == T_FLOAT || type == T_DOUBLE) {
5648 _first_reg = pd_first_fpu_reg;
5649 _last_reg = pd_last_fpu_reg;
5650 } else {
5651 _first_reg = pd_first_cpu_reg;
5652 _last_reg = FrameMap::last_cpu_reg();
5653 }
5654
5655 assert(0 <= _first_reg && _first_reg < LinearScan::nof_regs, "out of range");
5656 assert(0 <= _last_reg && _last_reg < LinearScan::nof_regs, "out of range");
5657 }
5658
5659
5660 bool LinearScanWalker::is_move(LIR_Op* op, Interval* from, Interval* to) {
5661 if (op->code() != lir_move) {
5662 return false;
5663 }
5664 assert(op->as_Op1() != NULL, "move must be LIR_Op1");
5665
5666 LIR_Opr in = ((LIR_Op1*)op)->in_opr();
5667 LIR_Opr res = ((LIR_Op1*)op)->result_opr();
5668 return in->is_virtual() && res->is_virtual() && in->vreg_number() == from->reg_num() && res->vreg_number() == to->reg_num();
5669 }
5670
5671 // optimization (especially for phi functions of nested loops):
5672 // assign same spill slot to non-intersecting intervals
5673 void LinearScanWalker::combine_spilled_intervals(Interval* cur) {
5674 if (cur->is_split_child()) {
5675 // optimization is only suitable for split parents
5676 return;
5677 }
5678
5679 Interval* register_hint = cur->register_hint(false);
5680 if (register_hint == NULL) {
5681 // cur is not the target of a move, otherwise register_hint would be set
5682 return;
5683 }
5684 assert(register_hint->is_split_parent(), "register hint must be split parent");
5685
5686 if (cur->spill_state() != noOptimization || register_hint->spill_state() != noOptimization) {
5687 // combining the stack slots for intervals where spill move optimization is applied
5688 // is not benefitial and would cause problems
5689 return;
5690 }
5691
5692 int begin_pos = cur->from();
5693 int end_pos = cur->to();
5694 if (end_pos > allocator()->max_lir_op_id() || (begin_pos & 1) != 0 || (end_pos & 1) != 0) {
5695 // safety check that lir_op_with_id is allowed
5696 return;
5697 }
5698
5699 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)) {
5700 // cur and register_hint are not connected with two moves
5701 return;
5702 }
5703
5704 Interval* begin_hint = register_hint->split_child_at_op_id(begin_pos, LIR_OpVisitState::inputMode);
5705 Interval* end_hint = register_hint->split_child_at_op_id(end_pos, LIR_OpVisitState::outputMode);
5706 if (begin_hint == end_hint || begin_hint->to() != begin_pos || end_hint->from() != end_pos) {
5707 // register_hint must be split, otherwise the re-writing of use positions does not work
5708 return;
5709 }
5710
5711 assert(begin_hint->assigned_reg() != any_reg, "must have register assigned");
5712 assert(end_hint->assigned_reg() == any_reg, "must not have register assigned");
5713 assert(cur->first_usage(mustHaveRegister) == begin_pos, "must have use position at begin of interval because of move");
5714 assert(end_hint->first_usage(mustHaveRegister) == end_pos, "must have use position at begin of interval because of move");
5715
5716 if (begin_hint->assigned_reg() < LinearScan::nof_regs) {
5717 // register_hint is not spilled at begin_pos, so it would not be benefitial to immediately spill cur
5718 return;
5719 }
5720 assert(register_hint->canonical_spill_slot() != -1, "must be set when part of interval was spilled");
5721
5722 // modify intervals such that cur gets the same stack slot as register_hint
5723 // delete use positions to prevent the intervals to get a register at beginning
5724 cur->set_canonical_spill_slot(register_hint->canonical_spill_slot());
5725 cur->remove_first_use_pos();
5726 end_hint->remove_first_use_pos();
5727 }
5728
5729
5730 // allocate a physical register or memory location to an interval
5731 bool LinearScanWalker::activate_current() {
5732 Interval* cur = current();
5733 bool result = true;
5734
5735 TRACE_LINEAR_SCAN(2, tty->print ("+++++ activating interval "); cur->print());
5736 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()));
5737
5738 if (cur->assigned_reg() >= LinearScan::nof_regs) {
5739 // activating an interval that has a stack slot assigned -> split it at first use position
5740 // used for method parameters
5741 TRACE_LINEAR_SCAN(4, tty->print_cr(" interval has spill slot assigned (method parameter) -> split it before first use"));
5742
5743 split_stack_interval(cur);
5744 result = false;
5745
5746 } else if (allocator()->gen()->is_vreg_flag_set(cur->reg_num(), LIRGenerator::must_start_in_memory)) {
5747 // activating an interval that must start in a stack slot, but may get a register later
5748 // used for lir_roundfp: rounding is done by store to stack and reload later
5749 TRACE_LINEAR_SCAN(4, tty->print_cr(" interval must start in stack slot -> split it before first use"));
5750 assert(cur->assigned_reg() == any_reg && cur->assigned_regHi() == any_reg, "register already assigned");
5751
5752 allocator()->assign_spill_slot(cur);
5753 split_stack_interval(cur);
5754 result = false;
5755
5756 } else if (cur->assigned_reg() == any_reg) {
5757 // interval has not assigned register -> normal allocation
5758 // (this is the normal case for most intervals)
5759 TRACE_LINEAR_SCAN(4, tty->print_cr(" normal allocation of register"));
5760
5761 // assign same spill slot to non-intersecting intervals
5762 combine_spilled_intervals(cur);
5763
5764 init_vars_for_alloc(cur);
5765 if (no_allocation_possible(cur) || !alloc_free_reg(cur)) {
5766 // no empty register available.
5767 // split and spill another interval so that this interval gets a register
5768 alloc_locked_reg(cur);
5769 }
5770
5771 // spilled intervals need not be move to active-list
5772 if (cur->assigned_reg() >= LinearScan::nof_regs) {
5773 result = false;
5774 }
5775 }
5776
5777 // load spilled values that become active from stack slot to register
5778 if (cur->insert_move_when_activated()) {
5779 assert(cur->is_split_child(), "must be");
5780 assert(cur->current_split_child() != NULL, "must be");
5781 assert(cur->current_split_child()->reg_num() != cur->reg_num(), "cannot insert move between same interval");
5782 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()));
5783
5784 insert_move(cur->from(), cur->current_split_child(), cur);
5785 }
5786 cur->make_current_split_child();
5787
5788 return result; // true = interval is moved to active list
5789 }
5790
5791
5792 // Implementation of EdgeMoveOptimizer
5793
5794 EdgeMoveOptimizer::EdgeMoveOptimizer() :
5795 _edge_instructions(4),
5796 _edge_instructions_idx(4)
5797 {
5798 }
5799
5800 void EdgeMoveOptimizer::optimize(BlockList* code) {
5801 EdgeMoveOptimizer optimizer = EdgeMoveOptimizer();
5802
5803 // ignore the first block in the list (index 0 is not processed)
5804 for (int i = code->length() - 1; i >= 1; i--) {
5805 BlockBegin* block = code->at(i);
5806
5807 if (block->number_of_preds() > 1 && !block->is_set(BlockBegin::exception_entry_flag)) {
5808 optimizer.optimize_moves_at_block_end(block);
5809 }
5810 if (block->number_of_sux() == 2) {
5811 optimizer.optimize_moves_at_block_begin(block);
5812 }
5813 }
5814 }
5815
5816
5817 // clear all internal data structures
5818 void EdgeMoveOptimizer::init_instructions() {
5819 _edge_instructions.clear();
5820 _edge_instructions_idx.clear();
5821 }
5822
5823 // append a lir-instruction-list and the index of the current operation in to the list
5824 void EdgeMoveOptimizer::append_instructions(LIR_OpList* instructions, int instructions_idx) {
5825 _edge_instructions.append(instructions);
5826 _edge_instructions_idx.append(instructions_idx);
5827 }
5828
5829 // return the current operation of the given edge (predecessor or successor)
5830 LIR_Op* EdgeMoveOptimizer::instruction_at(int edge) {
5831 LIR_OpList* instructions = _edge_instructions.at(edge);
5832 int idx = _edge_instructions_idx.at(edge);
5833
5834 if (idx < instructions->length()) {
5835 return instructions->at(idx);
5836 } else {
5837 return NULL;
5838 }
5839 }
5840
5841 // removes the current operation of the given edge (predecessor or successor)
5842 void EdgeMoveOptimizer::remove_cur_instruction(int edge, bool decrement_index) {
5843 LIR_OpList* instructions = _edge_instructions.at(edge);
5844 int idx = _edge_instructions_idx.at(edge);
5845 instructions->remove_at(idx);
5846
5847 if (decrement_index) {
5848 _edge_instructions_idx.at_put(edge, idx - 1);
5849 }
5850 }
5851
5852
5853 bool EdgeMoveOptimizer::operations_different(LIR_Op* op1, LIR_Op* op2) {
5854 if (op1 == NULL || op2 == NULL) {
5855 // at least one block is already empty -> no optimization possible
5856 return true;
5857 }
5858
5859 if (op1->code() == lir_move && op2->code() == lir_move) {
5860 assert(op1->as_Op1() != NULL, "move must be LIR_Op1");
5861 assert(op2->as_Op1() != NULL, "move must be LIR_Op1");
5862 LIR_Op1* move1 = (LIR_Op1*)op1;
5863 LIR_Op1* move2 = (LIR_Op1*)op2;
5864 if (move1->info() == move2->info() && move1->in_opr() == move2->in_opr() && move1->result_opr() == move2->result_opr()) {
5865 // these moves are exactly equal and can be optimized
5866 return false;
5867 }
5868
5869 } else if (op1->code() == lir_fxch && op2->code() == lir_fxch) {
5870 assert(op1->as_Op1() != NULL, "fxch must be LIR_Op1");
5871 assert(op2->as_Op1() != NULL, "fxch must be LIR_Op1");
5872 LIR_Op1* fxch1 = (LIR_Op1*)op1;
5873 LIR_Op1* fxch2 = (LIR_Op1*)op2;
5874 if (fxch1->in_opr()->as_jint() == fxch2->in_opr()->as_jint()) {
5875 // equal FPU stack operations can be optimized
5876 return false;
5877 }
5878
5879 } else if (op1->code() == lir_fpop_raw && op2->code() == lir_fpop_raw) {
5880 // equal FPU stack operations can be optimized
5881 return false;
5882 }
5883
5884 // no optimization possible
5885 return true;
5886 }
5887
5888 void EdgeMoveOptimizer::optimize_moves_at_block_end(BlockBegin* block) {
5889 TRACE_LINEAR_SCAN(4, tty->print_cr("optimizing moves at end of block B%d", block->block_id()));
5890
5891 if (block->is_predecessor(block)) {
5892 // currently we can't handle this correctly.
5893 return;
5894 }
5895
5896 init_instructions();
5897 int num_preds = block->number_of_preds();
5898 assert(num_preds > 1, "do not call otherwise");
5899 assert(!block->is_set(BlockBegin::exception_entry_flag), "exception handlers not allowed");
5900
5901 // setup a list with the lir-instructions of all predecessors
5902 int i;
5903 for (i = 0; i < num_preds; i++) {
5904 BlockBegin* pred = block->pred_at(i);
5905 LIR_OpList* pred_instructions = pred->lir()->instructions_list();
5906
5907 if (pred->number_of_sux() != 1) {
5908 // this can happen with switch-statements where multiple edges are between
5909 // the same blocks.
5910 return;
5911 }
5912
5913 assert(pred->number_of_sux() == 1, "can handle only one successor");
5914 assert(pred->sux_at(0) == block, "invalid control flow");
5915 assert(pred_instructions->last()->code() == lir_branch, "block with successor must end with branch");
5916 assert(pred_instructions->last()->as_OpBranch() != NULL, "branch must be LIR_OpBranch");
5917 assert(pred_instructions->last()->as_OpBranch()->cond() == lir_cond_always, "block must end with unconditional branch");
5918
5919 if (pred_instructions->last()->info() != NULL) {
5920 // can not optimize instructions when debug info is needed
5921 return;
5922 }
5923
5924 // ignore the unconditional branch at the end of the block
5925 append_instructions(pred_instructions, pred_instructions->length() - 2);
5926 }
5927
5928
5929 // process lir-instructions while all predecessors end with the same instruction
5930 while (true) {
5931 LIR_Op* op = instruction_at(0);
5932 for (i = 1; i < num_preds; i++) {
5933 if (operations_different(op, instruction_at(i))) {
5934 // these instructions are different and cannot be optimized ->
5935 // no further optimization possible
5936 return;
5937 }
5938 }
5939
5940 TRACE_LINEAR_SCAN(4, tty->print("found instruction that is equal in all %d predecessors: ", num_preds); op->print());
5941
5942 // insert the instruction at the beginning of the current block
5943 block->lir()->insert_before(1, op);
5944
5945 // delete the instruction at the end of all predecessors
5946 for (i = 0; i < num_preds; i++) {
5947 remove_cur_instruction(i, true);
5948 }
5949 }
5950 }
5951
5952
5953 void EdgeMoveOptimizer::optimize_moves_at_block_begin(BlockBegin* block) {
5954 TRACE_LINEAR_SCAN(4, tty->print_cr("optimization moves at begin of block B%d", block->block_id()));
5955
5956 init_instructions();
5957 int num_sux = block->number_of_sux();
5958
5959 LIR_OpList* cur_instructions = block->lir()->instructions_list();
5960
5961 assert(num_sux == 2, "method should not be called otherwise");
5962 assert(cur_instructions->last()->code() == lir_branch, "block with successor must end with branch");
5963 assert(cur_instructions->last()->as_OpBranch() != NULL, "branch must be LIR_OpBranch");
5964 assert(cur_instructions->last()->as_OpBranch()->cond() == lir_cond_always, "block must end with unconditional branch");
5965
5966 if (cur_instructions->last()->info() != NULL) {
5967 // can no optimize instructions when debug info is needed
5968 return;
5969 }
5970
5971 LIR_Op* branch = cur_instructions->at(cur_instructions->length() - 2);
5972 if (branch->info() != NULL || (branch->code() != lir_branch && branch->code() != lir_cond_float_branch)) {
5973 // not a valid case for optimization
5974 // currently, only blocks that end with two branches (conditional branch followed
5975 // by unconditional branch) are optimized
5976 return;
5977 }
5978
5979 // now it is guaranteed that the block ends with two branch instructions.
5980 // the instructions are inserted at the end of the block before these two branches
5981 int insert_idx = cur_instructions->length() - 2;
5982
5983 int i;
5984 #ifdef ASSERT
5985 for (i = insert_idx - 1; i >= 0; i--) {
5986 LIR_Op* op = cur_instructions->at(i);
5987 if ((op->code() == lir_branch || op->code() == lir_cond_float_branch) && ((LIR_OpBranch*)op)->block() != NULL) {
5988 assert(false, "block with two successors can have only two branch instructions");
5989 }
5990 }
5991 #endif
5992
5993 // setup a list with the lir-instructions of all successors
5994 for (i = 0; i < num_sux; i++) {
5995 BlockBegin* sux = block->sux_at(i);
5996 LIR_OpList* sux_instructions = sux->lir()->instructions_list();
5997
5998 assert(sux_instructions->at(0)->code() == lir_label, "block must start with label");
5999
6000 if (sux->number_of_preds() != 1) {
6001 // this can happen with switch-statements where multiple edges are between
6002 // the same blocks.
6003 return;
6004 }
6005 assert(sux->pred_at(0) == block, "invalid control flow");
6006 assert(!sux->is_set(BlockBegin::exception_entry_flag), "exception handlers not allowed");
6007
6008 // ignore the label at the beginning of the block
6009 append_instructions(sux_instructions, 1);
6010 }
6011
6012 // process lir-instructions while all successors begin with the same instruction
6013 while (true) {
6014 LIR_Op* op = instruction_at(0);
6015 for (i = 1; i < num_sux; i++) {
6016 if (operations_different(op, instruction_at(i))) {
6017 // these instructions are different and cannot be optimized ->
6018 // no further optimization possible
6019 return;
6020 }
6021 }
6022
6023 TRACE_LINEAR_SCAN(4, tty->print("----- found instruction that is equal in all %d successors: ", num_sux); op->print());
6024
6025 // insert instruction at end of current block
6026 block->lir()->insert_before(insert_idx, op);
6027 insert_idx++;
6028
6029 // delete the instructions at the beginning of all successors
6030 for (i = 0; i < num_sux; i++) {
6031 remove_cur_instruction(i, false);
6032 }
6033 }
6034 }
6035
6036
6037 // Implementation of ControlFlowOptimizer
6038
6039 ControlFlowOptimizer::ControlFlowOptimizer() :
6040 _original_preds(4)
6041 {
6042 }
6043
6044 void ControlFlowOptimizer::optimize(BlockList* code) {
6045 ControlFlowOptimizer optimizer = ControlFlowOptimizer();
6046
6047 // push the OSR entry block to the end so that we're not jumping over it.
6048 BlockBegin* osr_entry = code->at(0)->end()->as_Base()->osr_entry();
6049 if (osr_entry) {
6050 int index = osr_entry->linear_scan_number();
6051 assert(code->at(index) == osr_entry, "wrong index");
6052 code->remove_at(index);
6053 code->append(osr_entry);
6054 }
6055
6056 optimizer.reorder_short_loops(code);
6057 optimizer.delete_empty_blocks(code);
6058 optimizer.delete_unnecessary_jumps(code);
6059 optimizer.delete_jumps_to_return(code);
6060 }
6061
6062 void ControlFlowOptimizer::reorder_short_loop(BlockList* code, BlockBegin* header_block, int header_idx) {
6063 int i = header_idx + 1;
6064 int max_end = MIN2(header_idx + ShortLoopSize, code->length());
6065 while (i < max_end && code->at(i)->loop_depth() >= header_block->loop_depth()) {
6066 i++;
6067 }
6068
6069 if (i == code->length() || code->at(i)->loop_depth() < header_block->loop_depth()) {
6070 int end_idx = i - 1;
6071 BlockBegin* end_block = code->at(end_idx);
6072
6073 if (end_block->number_of_sux() == 1 && end_block->sux_at(0) == header_block) {
6074 // short loop from header_idx to end_idx found -> reorder blocks such that
6075 // the header_block is the last block instead of the first block of the loop
6076 TRACE_LINEAR_SCAN(1, tty->print_cr("Reordering short loop: length %d, header B%d, end B%d",
6077 end_idx - header_idx + 1,
6078 header_block->block_id(), end_block->block_id()));
6079
6080 for (int j = header_idx; j < end_idx; j++) {
6081 code->at_put(j, code->at(j + 1));
6082 }
6083 code->at_put(end_idx, header_block);
6084
6085 // correct the flags so that any loop alignment occurs in the right place.
6086 assert(code->at(end_idx)->is_set(BlockBegin::backward_branch_target_flag), "must be backward branch target");
6087 code->at(end_idx)->clear(BlockBegin::backward_branch_target_flag);
6088 code->at(header_idx)->set(BlockBegin::backward_branch_target_flag);
6089 }
6090 }
6091 }
6092
6093 void ControlFlowOptimizer::reorder_short_loops(BlockList* code) {
6094 for (int i = code->length() - 1; i >= 0; i--) {
6095 BlockBegin* block = code->at(i);
6096
6097 if (block->is_set(BlockBegin::linear_scan_loop_header_flag)) {
6098 reorder_short_loop(code, block, i);
6099 }
6100 }
6101
6102 DEBUG_ONLY(verify(code));
6103 }
6104
6105 // only blocks with exactly one successor can be deleted. Such blocks
6106 // must always end with an unconditional branch to this successor
6107 bool ControlFlowOptimizer::can_delete_block(BlockBegin* block) {
6108 if (block->number_of_sux() != 1 || block->number_of_exception_handlers() != 0 || block->is_entry_block()) {
6109 return false;
6110 }
6111
6112 LIR_OpList* instructions = block->lir()->instructions_list();
6113
6114 assert(instructions->length() >= 2, "block must have label and branch");
6115 assert(instructions->at(0)->code() == lir_label, "first instruction must always be a label");
6116 assert(instructions->last()->as_OpBranch() != NULL, "last instrcution must always be a branch");
6117 assert(instructions->last()->as_OpBranch()->cond() == lir_cond_always, "branch must be unconditional");
6118 assert(instructions->last()->as_OpBranch()->block() == block->sux_at(0), "branch target must be the successor");
6119
6120 // block must have exactly one successor
6121
6122 if (instructions->length() == 2 && instructions->last()->info() == NULL) {
6123 return true;
6124 }
6125 return false;
6126 }
6127
6128 // substitute branch targets in all branch-instructions of this blocks
6129 void ControlFlowOptimizer::substitute_branch_target(BlockBegin* block, BlockBegin* target_from, BlockBegin* target_to) {
6130 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()));
6131
6132 LIR_OpList* instructions = block->lir()->instructions_list();
6133
6134 assert(instructions->at(0)->code() == lir_label, "first instruction must always be a label");
6135 for (int i = instructions->length() - 1; i >= 1; i--) {
6136 LIR_Op* op = instructions->at(i);
6137
6138 if (op->code() == lir_branch || op->code() == lir_cond_float_branch) {
6139 assert(op->as_OpBranch() != NULL, "branch must be of type LIR_OpBranch");
6140 LIR_OpBranch* branch = (LIR_OpBranch*)op;
6141
6142 if (branch->block() == target_from) {
6143 branch->change_block(target_to);
6144 }
6145 if (branch->ublock() == target_from) {
6146 branch->change_ublock(target_to);
6147 }
6148 }
6149 }
6150 }
6151
6152 void ControlFlowOptimizer::delete_empty_blocks(BlockList* code) {
6153 int old_pos = 0;
6154 int new_pos = 0;
6155 int num_blocks = code->length();
6156
6157 while (old_pos < num_blocks) {
6158 BlockBegin* block = code->at(old_pos);
6159
6160 if (can_delete_block(block)) {
6161 BlockBegin* new_target = block->sux_at(0);
6162
6163 // propagate backward branch target flag for correct code alignment
6164 if (block->is_set(BlockBegin::backward_branch_target_flag)) {
6165 new_target->set(BlockBegin::backward_branch_target_flag);
6166 }
6167
6168 // collect a list with all predecessors that contains each predecessor only once
6169 // the predecessors of cur are changed during the substitution, so a copy of the
6170 // predecessor list is necessary
6171 int j;
6172 _original_preds.clear();
6173 for (j = block->number_of_preds() - 1; j >= 0; j--) {
6174 BlockBegin* pred = block->pred_at(j);
6175 if (_original_preds.index_of(pred) == -1) {
6176 _original_preds.append(pred);
6177 }
6178 }
6179
6180 for (j = _original_preds.length() - 1; j >= 0; j--) {
6181 BlockBegin* pred = _original_preds.at(j);
6182 substitute_branch_target(pred, block, new_target);
6183 pred->substitute_sux(block, new_target);
6184 }
6185 } else {
6186 // adjust position of this block in the block list if blocks before
6187 // have been deleted
6188 if (new_pos != old_pos) {
6189 code->at_put(new_pos, code->at(old_pos));
6190 }
6191 new_pos++;
6192 }
6193 old_pos++;
6194 }
6195 code->truncate(new_pos);
6196
6197 DEBUG_ONLY(verify(code));
6198 }
6199
6200 void ControlFlowOptimizer::delete_unnecessary_jumps(BlockList* code) {
6201 // skip the last block because there a branch is always necessary
6202 for (int i = code->length() - 2; i >= 0; i--) {
6203 BlockBegin* block = code->at(i);
6204 LIR_OpList* instructions = block->lir()->instructions_list();
6205
6206 LIR_Op* last_op = instructions->last();
6207 if (last_op->code() == lir_branch) {
6208 assert(last_op->as_OpBranch() != NULL, "branch must be of type LIR_OpBranch");
6209 LIR_OpBranch* last_branch = (LIR_OpBranch*)last_op;
6210
6211 assert(last_branch->block() != NULL, "last branch must always have a block as target");
6212 assert(last_branch->label() == last_branch->block()->label(), "must be equal");
6213
6214 if (last_branch->info() == NULL) {
6215 if (last_branch->block() == code->at(i + 1)) {
6216
6217 TRACE_LINEAR_SCAN(3, tty->print_cr("Deleting unconditional branch at end of block B%d", block->block_id()));
6218
6219 // delete last branch instruction
6220 instructions->truncate(instructions->length() - 1);
6221
6222 } else {
6223 LIR_Op* prev_op = instructions->at(instructions->length() - 2);
6224 if (prev_op->code() == lir_branch || prev_op->code() == lir_cond_float_branch) {
6225 assert(prev_op->as_OpBranch() != NULL, "branch must be of type LIR_OpBranch");
6226 LIR_OpBranch* prev_branch = (LIR_OpBranch*)prev_op;
6227
6228 LIR_Op2* prev_cmp = NULL;
6229
6230 for(int j = instructions->length() - 3; j >= 0 && prev_cmp == NULL; j--) {
6231 prev_op = instructions->at(j);
6232 if(prev_op->code() == lir_cmp) {
6233 assert(prev_op->as_Op2() != NULL, "branch must be of type LIR_Op2");
6234 prev_cmp = (LIR_Op2*)prev_op;
6235 assert(prev_branch->cond() == prev_cmp->condition(), "should be the same");
6236 }
6237 }
6238 assert(prev_cmp != NULL, "should have found comp instruction for branch");
6239 if (prev_branch->block() == code->at(i + 1) && prev_branch->info() == NULL) {
6240
6241 TRACE_LINEAR_SCAN(3, tty->print_cr("Negating conditional branch and deleting unconditional branch at end of block B%d", block->block_id()));
6242
6243 // eliminate a conditional branch to the immediate successor
6244 prev_branch->change_block(last_branch->block());
6245 prev_branch->negate_cond();
6246 prev_cmp->set_condition(prev_branch->cond());
6247 instructions->truncate(instructions->length() - 1);
6248 }
6249 }
6250 }
6251 }
6252 }
6253 }
6254
6255 DEBUG_ONLY(verify(code));
6256 }
6257
6258 void ControlFlowOptimizer::delete_jumps_to_return(BlockList* code) {
6259 #ifdef ASSERT
6260 BitMap return_converted(BlockBegin::number_of_blocks());
6261 return_converted.clear();
6262 #endif
6263
6264 for (int i = code->length() - 1; i >= 0; i--) {
6265 BlockBegin* block = code->at(i);
6266 LIR_OpList* cur_instructions = block->lir()->instructions_list();
6267 LIR_Op* cur_last_op = cur_instructions->last();
6268
6269 assert(cur_instructions->at(0)->code() == lir_label, "first instruction must always be a label");
6270 if (cur_instructions->length() == 2 && cur_last_op->code() == lir_return) {
6271 // the block contains only a label and a return
6272 // if a predecessor ends with an unconditional jump to this block, then the jump
6273 // can be replaced with a return instruction
6274 //
6275 // Note: the original block with only a return statement cannot be deleted completely
6276 // because the predecessors might have other (conditional) jumps to this block
6277 // -> this may lead to unnecesary return instructions in the final code
6278
6279 assert(cur_last_op->info() == NULL, "return instructions do not have debug information");
6280 assert(block->number_of_sux() == 0 ||
6281 (return_converted.at(block->block_id()) && block->number_of_sux() == 1),
6282 "blocks that end with return must not have successors");
6283
6284 assert(cur_last_op->as_Op1() != NULL, "return must be LIR_Op1");
6285 LIR_Opr return_opr = ((LIR_Op1*)cur_last_op)->in_opr();
6286
6287 for (int j = block->number_of_preds() - 1; j >= 0; j--) {
6288 BlockBegin* pred = block->pred_at(j);
6289 LIR_OpList* pred_instructions = pred->lir()->instructions_list();
6290 LIR_Op* pred_last_op = pred_instructions->last();
6291
6292 if (pred_last_op->code() == lir_branch) {
6293 assert(pred_last_op->as_OpBranch() != NULL, "branch must be LIR_OpBranch");
6294 LIR_OpBranch* pred_last_branch = (LIR_OpBranch*)pred_last_op;
6295
6296 if (pred_last_branch->block() == block && pred_last_branch->cond() == lir_cond_always && pred_last_branch->info() == NULL) {
6297 // replace the jump to a return with a direct return
6298 // Note: currently the edge between the blocks is not deleted
6299 pred_instructions->at_put(pred_instructions->length() - 1, new LIR_Op1(lir_return, return_opr));
6300 #ifdef ASSERT
6301 return_converted.set_bit(pred->block_id());
6302 #endif
6303 }
6304 }
6305 }
6306 }
6307 }
6308 }
6309
6310
6311 #ifdef ASSERT
6312 void ControlFlowOptimizer::verify(BlockList* code) {
6313 for (int i = 0; i < code->length(); i++) {
6314 BlockBegin* block = code->at(i);
6315 LIR_OpList* instructions = block->lir()->instructions_list();
6316
6317 int j;
6318 for (j = 0; j < instructions->length(); j++) {
6319 LIR_OpBranch* op_branch = instructions->at(j)->as_OpBranch();
6320
6321 if (op_branch != NULL) {
6322 assert(op_branch->block() == NULL || code->index_of(op_branch->block()) != -1, "branch target not valid");
6323 assert(op_branch->ublock() == NULL || code->index_of(op_branch->ublock()) != -1, "branch target not valid");
6324 }
6325 }
6326
6327 for (j = 0; j < block->number_of_sux() - 1; j++) {
6328 BlockBegin* sux = block->sux_at(j);
6329 assert(code->index_of(sux) != -1, "successor not valid");
6330 }
6331
6332 for (j = 0; j < block->number_of_preds() - 1; j++) {
6333 BlockBegin* pred = block->pred_at(j);
6334 assert(code->index_of(pred) != -1, "successor not valid");
6335 }
6336 }
6337 }
6338 #endif
6339
6340
6341 #ifndef PRODUCT
6342
6343 // Implementation of LinearStatistic
6344
6345 const char* LinearScanStatistic::counter_name(int counter_idx) {
6346 switch (counter_idx) {
6347 case counter_method: return "compiled methods";
6348 case counter_fpu_method: return "methods using fpu";
6349 case counter_loop_method: return "methods with loops";
6350 case counter_exception_method:return "methods with xhandler";
6351
6352 case counter_loop: return "loops";
6353 case counter_block: return "blocks";
6354 case counter_loop_block: return "blocks inside loop";
6355 case counter_exception_block: return "exception handler entries";
6356 case counter_interval: return "intervals";
6357 case counter_fixed_interval: return "fixed intervals";
6358 case counter_range: return "ranges";
6359 case counter_fixed_range: return "fixed ranges";
6360 case counter_use_pos: return "use positions";
6361 case counter_fixed_use_pos: return "fixed use positions";
6362 case counter_spill_slots: return "spill slots";
6363
6364 // counter for classes of lir instructions
6365 case counter_instruction: return "total instructions";
6366 case counter_label: return "labels";
6367 case counter_entry: return "method entries";
6368 case counter_return: return "method returns";
6369 case counter_call: return "method calls";
6370 case counter_move: return "moves";
6371 case counter_cmp: return "compare";
6372 case counter_cond_branch: return "conditional branches";
6373 case counter_uncond_branch: return "unconditional branches";
6374 case counter_stub_branch: return "branches to stub";
6375 case counter_alu: return "artithmetic + logic";
6376 case counter_alloc: return "allocations";
6377 case counter_sync: return "synchronisation";
6378 case counter_throw: return "throw";
6379 case counter_unwind: return "unwind";
6380 case counter_typecheck: return "type+null-checks";
6381 case counter_fpu_stack: return "fpu-stack";
6382 case counter_misc_inst: return "other instructions";
6383 case counter_other_inst: return "misc. instructions";
6384
6385 // counter for different types of moves
6386 case counter_move_total: return "total moves";
6387 case counter_move_reg_reg: return "register->register";
6388 case counter_move_reg_stack: return "register->stack";
6389 case counter_move_stack_reg: return "stack->register";
6390 case counter_move_stack_stack:return "stack->stack";
6391 case counter_move_reg_mem: return "register->memory";
6392 case counter_move_mem_reg: return "memory->register";
6393 case counter_move_const_any: return "constant->any";
6394
6395 case blank_line_1: return "";
6396 case blank_line_2: return "";
6397
6398 default: ShouldNotReachHere(); return "";
6399 }
6400 }
6401
6402 LinearScanStatistic::Counter LinearScanStatistic::base_counter(int counter_idx) {
6403 if (counter_idx == counter_fpu_method || counter_idx == counter_loop_method || counter_idx == counter_exception_method) {
6404 return counter_method;
6405 } else if (counter_idx == counter_loop_block || counter_idx == counter_exception_block) {
6406 return counter_block;
6407 } else if (counter_idx >= counter_instruction && counter_idx <= counter_other_inst) {
6408 return counter_instruction;
6409 } else if (counter_idx >= counter_move_total && counter_idx <= counter_move_const_any) {
6410 return counter_move_total;
6411 }
6412 return invalid_counter;
6413 }
6414
6415 LinearScanStatistic::LinearScanStatistic() {
6416 for (int i = 0; i < number_of_counters; i++) {
6417 _counters_sum[i] = 0;
6418 _counters_max[i] = -1;
6419 }
6420
6421 }
6422
6423 // add the method-local numbers to the total sum
6424 void LinearScanStatistic::sum_up(LinearScanStatistic &method_statistic) {
6425 for (int i = 0; i < number_of_counters; i++) {
6426 _counters_sum[i] += method_statistic._counters_sum[i];
6427 _counters_max[i] = MAX2(_counters_max[i], method_statistic._counters_sum[i]);
6428 }
6429 }
6430
6431 void LinearScanStatistic::print(const char* title) {
6432 if (CountLinearScan || TraceLinearScanLevel > 0) {
6433 tty->cr();
6434 tty->print_cr("***** LinearScan statistic - %s *****", title);
6435
6436 for (int i = 0; i < number_of_counters; i++) {
6437 if (_counters_sum[i] > 0 || _counters_max[i] >= 0) {
6438 tty->print("%25s: %8d", counter_name(i), _counters_sum[i]);
6439
6440 if (base_counter(i) != invalid_counter) {
6441 tty->print(" (%5.1f%%) ", _counters_sum[i] * 100.0 / _counters_sum[base_counter(i)]);
6442 } else {
6443 tty->print(" ");
6444 }
6445
6446 if (_counters_max[i] >= 0) {
6447 tty->print("%8d", _counters_max[i]);
6448 }
6449 }
6450 tty->cr();
6451 }
6452 }
6453 }
6454
6455 void LinearScanStatistic::collect(LinearScan* allocator) {
6456 inc_counter(counter_method);
6457 if (allocator->has_fpu_registers()) {
6458 inc_counter(counter_fpu_method);
6459 }
6460 if (allocator->num_loops() > 0) {
6461 inc_counter(counter_loop_method);
6462 }
6463 inc_counter(counter_loop, allocator->num_loops());
6464 inc_counter(counter_spill_slots, allocator->max_spills());
6465
6466 int i;
6467 for (i = 0; i < allocator->interval_count(); i++) {
6468 Interval* cur = allocator->interval_at(i);
6469
6470 if (cur != NULL) {
6471 inc_counter(counter_interval);
6472 inc_counter(counter_use_pos, cur->num_use_positions());
6473 if (LinearScan::is_precolored_interval(cur)) {
6474 inc_counter(counter_fixed_interval);
6475 inc_counter(counter_fixed_use_pos, cur->num_use_positions());
6476 }
6477
6478 Range* range = cur->first();
6479 while (range != Range::end()) {
6480 inc_counter(counter_range);
6481 if (LinearScan::is_precolored_interval(cur)) {
6482 inc_counter(counter_fixed_range);
6483 }
6484 range = range->next();
6485 }
6486 }
6487 }
6488
6489 bool has_xhandlers = false;
6490 // Note: only count blocks that are in code-emit order
6491 for (i = 0; i < allocator->ir()->code()->length(); i++) {
6492 BlockBegin* cur = allocator->ir()->code()->at(i);
6493
6494 inc_counter(counter_block);
6495 if (cur->loop_depth() > 0) {
6496 inc_counter(counter_loop_block);
6497 }
6498 if (cur->is_set(BlockBegin::exception_entry_flag)) {
6499 inc_counter(counter_exception_block);
6500 has_xhandlers = true;
6501 }
6502
6503 LIR_OpList* instructions = cur->lir()->instructions_list();
6504 for (int j = 0; j < instructions->length(); j++) {
6505 LIR_Op* op = instructions->at(j);
6506
6507 inc_counter(counter_instruction);
6508
6509 switch (op->code()) {
6510 case lir_label: inc_counter(counter_label); break;
6511 case lir_std_entry:
6512 case lir_osr_entry: inc_counter(counter_entry); break;
6513 case lir_return: inc_counter(counter_return); break;
6514
6515 case lir_rtcall:
6516 case lir_static_call:
6517 case lir_optvirtual_call:
6518 case lir_virtual_call: inc_counter(counter_call); break;
6519
6520 case lir_move: {
6521 inc_counter(counter_move);
6522 inc_counter(counter_move_total);
6523
6524 LIR_Opr in = op->as_Op1()->in_opr();
6525 LIR_Opr res = op->as_Op1()->result_opr();
6526 if (in->is_register()) {
6527 if (res->is_register()) {
6528 inc_counter(counter_move_reg_reg);
6529 } else if (res->is_stack()) {
6530 inc_counter(counter_move_reg_stack);
6531 } else if (res->is_address()) {
6532 inc_counter(counter_move_reg_mem);
6533 } else {
6534 ShouldNotReachHere();
6535 }
6536 } else if (in->is_stack()) {
6537 if (res->is_register()) {
6538 inc_counter(counter_move_stack_reg);
6539 } else {
6540 inc_counter(counter_move_stack_stack);
6541 }
6542 } else if (in->is_address()) {
6543 assert(res->is_register(), "must be");
6544 inc_counter(counter_move_mem_reg);
6545 } else if (in->is_constant()) {
6546 inc_counter(counter_move_const_any);
6547 } else {
6548 ShouldNotReachHere();
6549 }
6550 break;
6551 }
6552
6553 case lir_cmp: inc_counter(counter_cmp); break;
6554
6555 case lir_branch:
6556 case lir_cond_float_branch: {
6557 LIR_OpBranch* branch = op->as_OpBranch();
6558 if (branch->block() == NULL) {
6559 inc_counter(counter_stub_branch);
6560 } else if (branch->cond() == lir_cond_always) {
6561 inc_counter(counter_uncond_branch);
6562 } else {
6563 inc_counter(counter_cond_branch);
6564 }
6565 break;
6566 }
6567
6568 case lir_neg:
6569 case lir_add:
6570 case lir_sub:
6571 case lir_mul:
6572 case lir_mul_strictfp:
6573 case lir_div:
6574 case lir_div_strictfp:
6575 case lir_rem:
6576 case lir_sqrt:
6577 case lir_sin:
6578 case lir_cos:
6579 case lir_abs:
6580 case lir_log10:
6581 case lir_log:
6582 case lir_logic_and:
6583 case lir_logic_or:
6584 case lir_logic_xor:
6585 case lir_shl:
6586 case lir_shr:
6587 case lir_ushr: inc_counter(counter_alu); break;
6588
6589 case lir_alloc_object:
6590 case lir_alloc_array: inc_counter(counter_alloc); break;
6591
6592 case lir_monaddr:
6593 case lir_lock:
6594 case lir_unlock: inc_counter(counter_sync); break;
6595
6596 case lir_throw: inc_counter(counter_throw); break;
6597
6598 case lir_unwind: inc_counter(counter_unwind); break;
6599
6600 case lir_null_check:
6601 case lir_leal:
6602 case lir_instanceof:
6603 case lir_checkcast:
6604 case lir_store_check: inc_counter(counter_typecheck); break;
6605
6606 case lir_fpop_raw:
6607 case lir_fxch:
6608 case lir_fld: inc_counter(counter_fpu_stack); break;
6609
6610 case lir_nop:
6611 case lir_push:
6612 case lir_pop:
6613 case lir_convert:
6614 case lir_roundfp:
6615 case lir_cmove: inc_counter(counter_misc_inst); break;
6616
6617 default: inc_counter(counter_other_inst); break;
6618 }
6619 }
6620 }
6621
6622 if (has_xhandlers) {
6623 inc_counter(counter_exception_method);
6624 }
6625 }
6626
6627 void LinearScanStatistic::compute(LinearScan* allocator, LinearScanStatistic &global_statistic) {
6628 if (CountLinearScan || TraceLinearScanLevel > 0) {
6629
6630 LinearScanStatistic local_statistic = LinearScanStatistic();
6631
6632 local_statistic.collect(allocator);
6633 global_statistic.sum_up(local_statistic);
6634
6635 if (TraceLinearScanLevel > 2) {
6636 local_statistic.print("current local statistic");
6637 }
6638 }
6639 }
6640
6641
6642 // Implementation of LinearTimers
6643
6644 LinearScanTimers::LinearScanTimers() {
6645 for (int i = 0; i < number_of_timers; i++) {
6646 timer(i)->reset();
6647 }
6648 }
6649
6650 const char* LinearScanTimers::timer_name(int idx) {
6651 switch (idx) {
6652 case timer_do_nothing: return "Nothing (Time Check)";
6653 case timer_number_instructions: return "Number Instructions";
6654 case timer_compute_local_live_sets: return "Local Live Sets";
6655 case timer_compute_global_live_sets: return "Global Live Sets";
6656 case timer_build_intervals: return "Build Intervals";
6657 case timer_sort_intervals_before: return "Sort Intervals Before";
6658 case timer_allocate_registers: return "Allocate Registers";
6659 case timer_resolve_data_flow: return "Resolve Data Flow";
6660 case timer_sort_intervals_after: return "Sort Intervals After";
6661 case timer_eliminate_spill_moves: return "Spill optimization";
6662 case timer_assign_reg_num: return "Assign Reg Num";
6663 case timer_allocate_fpu_stack: return "Allocate FPU Stack";
6664 case timer_optimize_lir: return "Optimize LIR";
6665 default: ShouldNotReachHere(); return "";
6666 }
6667 }
6668
6669 void LinearScanTimers::begin_method() {
6670 if (TimeEachLinearScan) {
6671 // reset all timers to measure only current method
6672 for (int i = 0; i < number_of_timers; i++) {
6673 timer(i)->reset();
6674 }
6675 }
6676 }
6677
6678 void LinearScanTimers::end_method(LinearScan* allocator) {
6679 if (TimeEachLinearScan) {
6680
6681 double c = timer(timer_do_nothing)->seconds();
6682 double total = 0;
6683 for (int i = 1; i < number_of_timers; i++) {
6684 total += timer(i)->seconds() - c;
6685 }
6686
6687 if (total >= 0.0005) {
6688 // print all information in one line for automatic processing
6689 tty->print("@"); allocator->compilation()->method()->print_name();
6690
6691 tty->print("@ %d ", allocator->compilation()->method()->code_size());
6692 tty->print("@ %d ", allocator->block_at(allocator->block_count() - 1)->last_lir_instruction_id() / 2);
6693 tty->print("@ %d ", allocator->block_count());
6694 tty->print("@ %d ", allocator->num_virtual_regs());
6695 tty->print("@ %d ", allocator->interval_count());
6696 tty->print("@ %d ", allocator->_num_calls);
6697 tty->print("@ %d ", allocator->num_loops());
6698
6699 tty->print("@ %6.6f ", total);
6700 for (int i = 1; i < number_of_timers; i++) {
6701 tty->print("@ %4.1f ", ((timer(i)->seconds() - c) / total) * 100);
6702 }
6703 tty->cr();
6704 }
6705 }
6706 }
6707
6708 void LinearScanTimers::print(double total_time) {
6709 if (TimeLinearScan) {
6710 // correction value: sum of dummy-timer that only measures the time that
6711 // is necesary to start and stop itself
6712 double c = timer(timer_do_nothing)->seconds();
6713
6714 for (int i = 0; i < number_of_timers; i++) {
6715 double t = timer(i)->seconds();
6716 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);
6717 }
6718 }
6719 }
6720
6721 #endif // #ifndef PRODUCT