Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 1 | // Copyright 2012 the V8 project authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | #include "src/crankshaft/lithium-allocator.h" |
| 6 | |
| 7 | #include "src/crankshaft/hydrogen.h" |
| 8 | #include "src/crankshaft/lithium-inl.h" |
| 9 | #include "src/crankshaft/lithium-allocator-inl.h" |
| 10 | #include "src/register-configuration.h" |
| 11 | #include "src/string-stream.h" |
| 12 | |
| 13 | namespace v8 { |
| 14 | namespace internal { |
| 15 | |
| 16 | static inline LifetimePosition Min(LifetimePosition a, LifetimePosition b) { |
| 17 | return a.Value() < b.Value() ? a : b; |
| 18 | } |
| 19 | |
| 20 | |
| 21 | static inline LifetimePosition Max(LifetimePosition a, LifetimePosition b) { |
| 22 | return a.Value() > b.Value() ? a : b; |
| 23 | } |
| 24 | |
| 25 | |
| 26 | UsePosition::UsePosition(LifetimePosition pos, |
| 27 | LOperand* operand, |
| 28 | LOperand* hint) |
| 29 | : operand_(operand), |
| 30 | hint_(hint), |
| 31 | pos_(pos), |
| 32 | next_(NULL), |
| 33 | requires_reg_(false), |
| 34 | register_beneficial_(true) { |
| 35 | if (operand_ != NULL && operand_->IsUnallocated()) { |
| 36 | LUnallocated* unalloc = LUnallocated::cast(operand_); |
| 37 | requires_reg_ = unalloc->HasRegisterPolicy() || |
| 38 | unalloc->HasDoubleRegisterPolicy(); |
| 39 | register_beneficial_ = !unalloc->HasAnyPolicy(); |
| 40 | } |
| 41 | DCHECK(pos_.IsValid()); |
| 42 | } |
| 43 | |
| 44 | |
| 45 | bool UsePosition::HasHint() const { |
| 46 | return hint_ != NULL && !hint_->IsUnallocated(); |
| 47 | } |
| 48 | |
| 49 | |
| 50 | bool UsePosition::RequiresRegister() const { |
| 51 | return requires_reg_; |
| 52 | } |
| 53 | |
| 54 | |
| 55 | bool UsePosition::RegisterIsBeneficial() const { |
| 56 | return register_beneficial_; |
| 57 | } |
| 58 | |
| 59 | |
| 60 | void UseInterval::SplitAt(LifetimePosition pos, Zone* zone) { |
| 61 | DCHECK(Contains(pos) && pos.Value() != start().Value()); |
| 62 | UseInterval* after = new(zone) UseInterval(pos, end_); |
| 63 | after->next_ = next_; |
| 64 | next_ = after; |
| 65 | end_ = pos; |
| 66 | } |
| 67 | |
| 68 | |
| 69 | #ifdef DEBUG |
| 70 | |
| 71 | |
| 72 | void LiveRange::Verify() const { |
| 73 | UsePosition* cur = first_pos_; |
| 74 | while (cur != NULL) { |
| 75 | DCHECK(Start().Value() <= cur->pos().Value() && |
| 76 | cur->pos().Value() <= End().Value()); |
| 77 | cur = cur->next(); |
| 78 | } |
| 79 | } |
| 80 | |
| 81 | |
| 82 | bool LiveRange::HasOverlap(UseInterval* target) const { |
| 83 | UseInterval* current_interval = first_interval_; |
| 84 | while (current_interval != NULL) { |
| 85 | // Intervals overlap if the start of one is contained in the other. |
| 86 | if (current_interval->Contains(target->start()) || |
| 87 | target->Contains(current_interval->start())) { |
| 88 | return true; |
| 89 | } |
| 90 | current_interval = current_interval->next(); |
| 91 | } |
| 92 | return false; |
| 93 | } |
| 94 | |
| 95 | |
| 96 | #endif |
| 97 | |
| 98 | |
| 99 | LiveRange::LiveRange(int id, Zone* zone) |
| 100 | : id_(id), |
| 101 | spilled_(false), |
| 102 | kind_(UNALLOCATED_REGISTERS), |
| 103 | assigned_register_(kInvalidAssignment), |
| 104 | last_interval_(NULL), |
| 105 | first_interval_(NULL), |
| 106 | first_pos_(NULL), |
| 107 | parent_(NULL), |
| 108 | next_(NULL), |
| 109 | current_interval_(NULL), |
| 110 | last_processed_use_(NULL), |
| 111 | current_hint_operand_(NULL), |
| 112 | spill_operand_(new (zone) LOperand()), |
| 113 | spill_start_index_(kMaxInt) {} |
| 114 | |
| 115 | |
| 116 | void LiveRange::set_assigned_register(int reg, Zone* zone) { |
| 117 | DCHECK(!HasRegisterAssigned() && !IsSpilled()); |
| 118 | assigned_register_ = reg; |
| 119 | ConvertOperands(zone); |
| 120 | } |
| 121 | |
| 122 | |
| 123 | void LiveRange::MakeSpilled(Zone* zone) { |
| 124 | DCHECK(!IsSpilled()); |
| 125 | DCHECK(TopLevel()->HasAllocatedSpillOperand()); |
| 126 | spilled_ = true; |
| 127 | assigned_register_ = kInvalidAssignment; |
| 128 | ConvertOperands(zone); |
| 129 | } |
| 130 | |
| 131 | |
| 132 | bool LiveRange::HasAllocatedSpillOperand() const { |
| 133 | DCHECK(spill_operand_ != NULL); |
| 134 | return !spill_operand_->IsIgnored(); |
| 135 | } |
| 136 | |
| 137 | |
| 138 | void LiveRange::SetSpillOperand(LOperand* operand) { |
| 139 | DCHECK(!operand->IsUnallocated()); |
| 140 | DCHECK(spill_operand_ != NULL); |
| 141 | DCHECK(spill_operand_->IsIgnored()); |
| 142 | spill_operand_->ConvertTo(operand->kind(), operand->index()); |
| 143 | } |
| 144 | |
| 145 | |
| 146 | UsePosition* LiveRange::NextUsePosition(LifetimePosition start) { |
| 147 | UsePosition* use_pos = last_processed_use_; |
| 148 | if (use_pos == NULL) use_pos = first_pos(); |
| 149 | while (use_pos != NULL && use_pos->pos().Value() < start.Value()) { |
| 150 | use_pos = use_pos->next(); |
| 151 | } |
| 152 | last_processed_use_ = use_pos; |
| 153 | return use_pos; |
| 154 | } |
| 155 | |
| 156 | |
| 157 | UsePosition* LiveRange::NextUsePositionRegisterIsBeneficial( |
| 158 | LifetimePosition start) { |
| 159 | UsePosition* pos = NextUsePosition(start); |
| 160 | while (pos != NULL && !pos->RegisterIsBeneficial()) { |
| 161 | pos = pos->next(); |
| 162 | } |
| 163 | return pos; |
| 164 | } |
| 165 | |
| 166 | |
| 167 | UsePosition* LiveRange::PreviousUsePositionRegisterIsBeneficial( |
| 168 | LifetimePosition start) { |
| 169 | UsePosition* pos = first_pos(); |
| 170 | UsePosition* prev = NULL; |
| 171 | while (pos != NULL && pos->pos().Value() < start.Value()) { |
| 172 | if (pos->RegisterIsBeneficial()) prev = pos; |
| 173 | pos = pos->next(); |
| 174 | } |
| 175 | return prev; |
| 176 | } |
| 177 | |
| 178 | |
| 179 | UsePosition* LiveRange::NextRegisterPosition(LifetimePosition start) { |
| 180 | UsePosition* pos = NextUsePosition(start); |
| 181 | while (pos != NULL && !pos->RequiresRegister()) { |
| 182 | pos = pos->next(); |
| 183 | } |
| 184 | return pos; |
| 185 | } |
| 186 | |
| 187 | |
| 188 | bool LiveRange::CanBeSpilled(LifetimePosition pos) { |
| 189 | // We cannot spill a live range that has a use requiring a register |
| 190 | // at the current or the immediate next position. |
| 191 | UsePosition* use_pos = NextRegisterPosition(pos); |
| 192 | if (use_pos == NULL) return true; |
| 193 | return |
| 194 | use_pos->pos().Value() > pos.NextInstruction().InstructionEnd().Value(); |
| 195 | } |
| 196 | |
| 197 | |
| 198 | LOperand* LiveRange::CreateAssignedOperand(Zone* zone) { |
| 199 | LOperand* op = NULL; |
| 200 | if (HasRegisterAssigned()) { |
| 201 | DCHECK(!IsSpilled()); |
| 202 | switch (Kind()) { |
| 203 | case GENERAL_REGISTERS: |
| 204 | op = LRegister::Create(assigned_register(), zone); |
| 205 | break; |
| 206 | case DOUBLE_REGISTERS: |
| 207 | op = LDoubleRegister::Create(assigned_register(), zone); |
| 208 | break; |
| 209 | default: |
| 210 | UNREACHABLE(); |
| 211 | } |
| 212 | } else if (IsSpilled()) { |
| 213 | DCHECK(!HasRegisterAssigned()); |
| 214 | op = TopLevel()->GetSpillOperand(); |
| 215 | DCHECK(!op->IsUnallocated()); |
| 216 | } else { |
| 217 | LUnallocated* unalloc = new(zone) LUnallocated(LUnallocated::NONE); |
| 218 | unalloc->set_virtual_register(id_); |
| 219 | op = unalloc; |
| 220 | } |
| 221 | return op; |
| 222 | } |
| 223 | |
| 224 | |
| 225 | UseInterval* LiveRange::FirstSearchIntervalForPosition( |
| 226 | LifetimePosition position) const { |
| 227 | if (current_interval_ == NULL) return first_interval_; |
| 228 | if (current_interval_->start().Value() > position.Value()) { |
| 229 | current_interval_ = NULL; |
| 230 | return first_interval_; |
| 231 | } |
| 232 | return current_interval_; |
| 233 | } |
| 234 | |
| 235 | |
| 236 | void LiveRange::AdvanceLastProcessedMarker( |
| 237 | UseInterval* to_start_of, LifetimePosition but_not_past) const { |
| 238 | if (to_start_of == NULL) return; |
| 239 | if (to_start_of->start().Value() > but_not_past.Value()) return; |
| 240 | LifetimePosition start = |
| 241 | current_interval_ == NULL ? LifetimePosition::Invalid() |
| 242 | : current_interval_->start(); |
| 243 | if (to_start_of->start().Value() > start.Value()) { |
| 244 | current_interval_ = to_start_of; |
| 245 | } |
| 246 | } |
| 247 | |
| 248 | |
| 249 | void LiveRange::SplitAt(LifetimePosition position, |
| 250 | LiveRange* result, |
| 251 | Zone* zone) { |
| 252 | DCHECK(Start().Value() < position.Value()); |
| 253 | DCHECK(result->IsEmpty()); |
| 254 | // Find the last interval that ends before the position. If the |
| 255 | // position is contained in one of the intervals in the chain, we |
| 256 | // split that interval and use the first part. |
| 257 | UseInterval* current = FirstSearchIntervalForPosition(position); |
| 258 | |
| 259 | // If the split position coincides with the beginning of a use interval |
| 260 | // we need to split use positons in a special way. |
| 261 | bool split_at_start = false; |
| 262 | |
| 263 | if (current->start().Value() == position.Value()) { |
| 264 | // When splitting at start we need to locate the previous use interval. |
| 265 | current = first_interval_; |
| 266 | } |
| 267 | |
| 268 | while (current != NULL) { |
| 269 | if (current->Contains(position)) { |
| 270 | current->SplitAt(position, zone); |
| 271 | break; |
| 272 | } |
| 273 | UseInterval* next = current->next(); |
| 274 | if (next->start().Value() >= position.Value()) { |
| 275 | split_at_start = (next->start().Value() == position.Value()); |
| 276 | break; |
| 277 | } |
| 278 | current = next; |
| 279 | } |
| 280 | |
| 281 | // Partition original use intervals to the two live ranges. |
| 282 | UseInterval* before = current; |
| 283 | UseInterval* after = before->next(); |
| 284 | result->last_interval_ = (last_interval_ == before) |
| 285 | ? after // Only interval in the range after split. |
| 286 | : last_interval_; // Last interval of the original range. |
| 287 | result->first_interval_ = after; |
| 288 | last_interval_ = before; |
| 289 | |
| 290 | // Find the last use position before the split and the first use |
| 291 | // position after it. |
| 292 | UsePosition* use_after = first_pos_; |
| 293 | UsePosition* use_before = NULL; |
| 294 | if (split_at_start) { |
| 295 | // The split position coincides with the beginning of a use interval (the |
| 296 | // end of a lifetime hole). Use at this position should be attributed to |
| 297 | // the split child because split child owns use interval covering it. |
| 298 | while (use_after != NULL && use_after->pos().Value() < position.Value()) { |
| 299 | use_before = use_after; |
| 300 | use_after = use_after->next(); |
| 301 | } |
| 302 | } else { |
| 303 | while (use_after != NULL && use_after->pos().Value() <= position.Value()) { |
| 304 | use_before = use_after; |
| 305 | use_after = use_after->next(); |
| 306 | } |
| 307 | } |
| 308 | |
| 309 | // Partition original use positions to the two live ranges. |
| 310 | if (use_before != NULL) { |
| 311 | use_before->next_ = NULL; |
| 312 | } else { |
| 313 | first_pos_ = NULL; |
| 314 | } |
| 315 | result->first_pos_ = use_after; |
| 316 | |
| 317 | // Discard cached iteration state. It might be pointing |
| 318 | // to the use that no longer belongs to this live range. |
| 319 | last_processed_use_ = NULL; |
| 320 | current_interval_ = NULL; |
| 321 | |
| 322 | // Link the new live range in the chain before any of the other |
| 323 | // ranges linked from the range before the split. |
| 324 | result->parent_ = (parent_ == NULL) ? this : parent_; |
| 325 | result->kind_ = result->parent_->kind_; |
| 326 | result->next_ = next_; |
| 327 | next_ = result; |
| 328 | |
| 329 | #ifdef DEBUG |
| 330 | Verify(); |
| 331 | result->Verify(); |
| 332 | #endif |
| 333 | } |
| 334 | |
| 335 | |
| 336 | // This implements an ordering on live ranges so that they are ordered by their |
| 337 | // start positions. This is needed for the correctness of the register |
| 338 | // allocation algorithm. If two live ranges start at the same offset then there |
| 339 | // is a tie breaker based on where the value is first used. This part of the |
| 340 | // ordering is merely a heuristic. |
| 341 | bool LiveRange::ShouldBeAllocatedBefore(const LiveRange* other) const { |
| 342 | LifetimePosition start = Start(); |
| 343 | LifetimePosition other_start = other->Start(); |
| 344 | if (start.Value() == other_start.Value()) { |
| 345 | UsePosition* pos = first_pos(); |
| 346 | if (pos == NULL) return false; |
| 347 | UsePosition* other_pos = other->first_pos(); |
| 348 | if (other_pos == NULL) return true; |
| 349 | return pos->pos().Value() < other_pos->pos().Value(); |
| 350 | } |
| 351 | return start.Value() < other_start.Value(); |
| 352 | } |
| 353 | |
| 354 | |
| 355 | void LiveRange::ShortenTo(LifetimePosition start) { |
| 356 | LAllocator::TraceAlloc("Shorten live range %d to [%d\n", id_, start.Value()); |
| 357 | DCHECK(first_interval_ != NULL); |
| 358 | DCHECK(first_interval_->start().Value() <= start.Value()); |
| 359 | DCHECK(start.Value() < first_interval_->end().Value()); |
| 360 | first_interval_->set_start(start); |
| 361 | } |
| 362 | |
| 363 | |
| 364 | void LiveRange::EnsureInterval(LifetimePosition start, |
| 365 | LifetimePosition end, |
| 366 | Zone* zone) { |
| 367 | LAllocator::TraceAlloc("Ensure live range %d in interval [%d %d[\n", |
| 368 | id_, |
| 369 | start.Value(), |
| 370 | end.Value()); |
| 371 | LifetimePosition new_end = end; |
| 372 | while (first_interval_ != NULL && |
| 373 | first_interval_->start().Value() <= end.Value()) { |
| 374 | if (first_interval_->end().Value() > end.Value()) { |
| 375 | new_end = first_interval_->end(); |
| 376 | } |
| 377 | first_interval_ = first_interval_->next(); |
| 378 | } |
| 379 | |
| 380 | UseInterval* new_interval = new(zone) UseInterval(start, new_end); |
| 381 | new_interval->next_ = first_interval_; |
| 382 | first_interval_ = new_interval; |
| 383 | if (new_interval->next() == NULL) { |
| 384 | last_interval_ = new_interval; |
| 385 | } |
| 386 | } |
| 387 | |
| 388 | |
| 389 | void LiveRange::AddUseInterval(LifetimePosition start, |
| 390 | LifetimePosition end, |
| 391 | Zone* zone) { |
| 392 | LAllocator::TraceAlloc("Add to live range %d interval [%d %d[\n", |
| 393 | id_, |
| 394 | start.Value(), |
| 395 | end.Value()); |
| 396 | if (first_interval_ == NULL) { |
| 397 | UseInterval* interval = new(zone) UseInterval(start, end); |
| 398 | first_interval_ = interval; |
| 399 | last_interval_ = interval; |
| 400 | } else { |
| 401 | if (end.Value() == first_interval_->start().Value()) { |
| 402 | first_interval_->set_start(start); |
| 403 | } else if (end.Value() < first_interval_->start().Value()) { |
| 404 | UseInterval* interval = new(zone) UseInterval(start, end); |
| 405 | interval->set_next(first_interval_); |
| 406 | first_interval_ = interval; |
| 407 | } else { |
| 408 | // Order of instruction's processing (see ProcessInstructions) guarantees |
| 409 | // that each new use interval either precedes or intersects with |
| 410 | // last added interval. |
| 411 | DCHECK(start.Value() < first_interval_->end().Value()); |
| 412 | first_interval_->start_ = Min(start, first_interval_->start_); |
| 413 | first_interval_->end_ = Max(end, first_interval_->end_); |
| 414 | } |
| 415 | } |
| 416 | } |
| 417 | |
| 418 | |
| 419 | void LiveRange::AddUsePosition(LifetimePosition pos, |
| 420 | LOperand* operand, |
| 421 | LOperand* hint, |
| 422 | Zone* zone) { |
| 423 | LAllocator::TraceAlloc("Add to live range %d use position %d\n", |
| 424 | id_, |
| 425 | pos.Value()); |
| 426 | UsePosition* use_pos = new(zone) UsePosition(pos, operand, hint); |
| 427 | UsePosition* prev_hint = NULL; |
| 428 | UsePosition* prev = NULL; |
| 429 | UsePosition* current = first_pos_; |
| 430 | while (current != NULL && current->pos().Value() < pos.Value()) { |
| 431 | prev_hint = current->HasHint() ? current : prev_hint; |
| 432 | prev = current; |
| 433 | current = current->next(); |
| 434 | } |
| 435 | |
| 436 | if (prev == NULL) { |
| 437 | use_pos->set_next(first_pos_); |
| 438 | first_pos_ = use_pos; |
| 439 | } else { |
| 440 | use_pos->next_ = prev->next_; |
| 441 | prev->next_ = use_pos; |
| 442 | } |
| 443 | |
| 444 | if (prev_hint == NULL && use_pos->HasHint()) { |
| 445 | current_hint_operand_ = hint; |
| 446 | } |
| 447 | } |
| 448 | |
| 449 | |
| 450 | void LiveRange::ConvertOperands(Zone* zone) { |
| 451 | LOperand* op = CreateAssignedOperand(zone); |
| 452 | UsePosition* use_pos = first_pos(); |
| 453 | while (use_pos != NULL) { |
| 454 | DCHECK(Start().Value() <= use_pos->pos().Value() && |
| 455 | use_pos->pos().Value() <= End().Value()); |
| 456 | |
| 457 | if (use_pos->HasOperand()) { |
| 458 | DCHECK(op->IsRegister() || op->IsDoubleRegister() || |
| 459 | !use_pos->RequiresRegister()); |
| 460 | use_pos->operand()->ConvertTo(op->kind(), op->index()); |
| 461 | } |
| 462 | use_pos = use_pos->next(); |
| 463 | } |
| 464 | } |
| 465 | |
| 466 | |
| 467 | bool LiveRange::CanCover(LifetimePosition position) const { |
| 468 | if (IsEmpty()) return false; |
| 469 | return Start().Value() <= position.Value() && |
| 470 | position.Value() < End().Value(); |
| 471 | } |
| 472 | |
| 473 | |
| 474 | bool LiveRange::Covers(LifetimePosition position) { |
| 475 | if (!CanCover(position)) return false; |
| 476 | UseInterval* start_search = FirstSearchIntervalForPosition(position); |
| 477 | for (UseInterval* interval = start_search; |
| 478 | interval != NULL; |
| 479 | interval = interval->next()) { |
| 480 | DCHECK(interval->next() == NULL || |
| 481 | interval->next()->start().Value() >= interval->start().Value()); |
| 482 | AdvanceLastProcessedMarker(interval, position); |
| 483 | if (interval->Contains(position)) return true; |
| 484 | if (interval->start().Value() > position.Value()) return false; |
| 485 | } |
| 486 | return false; |
| 487 | } |
| 488 | |
| 489 | |
| 490 | LifetimePosition LiveRange::FirstIntersection(LiveRange* other) { |
| 491 | UseInterval* b = other->first_interval(); |
| 492 | if (b == NULL) return LifetimePosition::Invalid(); |
| 493 | LifetimePosition advance_last_processed_up_to = b->start(); |
| 494 | UseInterval* a = FirstSearchIntervalForPosition(b->start()); |
| 495 | while (a != NULL && b != NULL) { |
| 496 | if (a->start().Value() > other->End().Value()) break; |
| 497 | if (b->start().Value() > End().Value()) break; |
| 498 | LifetimePosition cur_intersection = a->Intersect(b); |
| 499 | if (cur_intersection.IsValid()) { |
| 500 | return cur_intersection; |
| 501 | } |
| 502 | if (a->start().Value() < b->start().Value()) { |
| 503 | a = a->next(); |
| 504 | if (a == NULL || a->start().Value() > other->End().Value()) break; |
| 505 | AdvanceLastProcessedMarker(a, advance_last_processed_up_to); |
| 506 | } else { |
| 507 | b = b->next(); |
| 508 | } |
| 509 | } |
| 510 | return LifetimePosition::Invalid(); |
| 511 | } |
| 512 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 513 | LAllocator::LAllocator(int num_values, HGraph* graph) |
Ben Murdoch | da12d29 | 2016-06-02 14:46:10 +0100 | [diff] [blame^] | 514 | : zone_(graph->isolate()->allocator()), |
| 515 | chunk_(NULL), |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 516 | live_in_sets_(graph->blocks()->length(), zone()), |
| 517 | live_ranges_(num_values * 2, zone()), |
| 518 | fixed_live_ranges_(NULL), |
| 519 | fixed_double_live_ranges_(NULL), |
| 520 | unhandled_live_ranges_(num_values * 2, zone()), |
| 521 | active_live_ranges_(8, zone()), |
| 522 | inactive_live_ranges_(8, zone()), |
| 523 | reusable_slots_(8, zone()), |
| 524 | next_virtual_register_(num_values), |
| 525 | first_artificial_register_(num_values), |
| 526 | mode_(UNALLOCATED_REGISTERS), |
| 527 | num_registers_(-1), |
| 528 | graph_(graph), |
| 529 | has_osr_entry_(false), |
| 530 | allocation_ok_(true) {} |
| 531 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 532 | void LAllocator::InitializeLivenessAnalysis() { |
| 533 | // Initialize the live_in sets for each block to NULL. |
| 534 | int block_count = graph_->blocks()->length(); |
| 535 | live_in_sets_.Initialize(block_count, zone()); |
| 536 | live_in_sets_.AddBlock(NULL, block_count, zone()); |
| 537 | } |
| 538 | |
| 539 | |
| 540 | BitVector* LAllocator::ComputeLiveOut(HBasicBlock* block) { |
| 541 | // Compute live out for the given block, except not including backward |
| 542 | // successor edges. |
| 543 | BitVector* live_out = new(zone()) BitVector(next_virtual_register_, zone()); |
| 544 | |
| 545 | // Process all successor blocks. |
| 546 | for (HSuccessorIterator it(block->end()); !it.Done(); it.Advance()) { |
| 547 | // Add values live on entry to the successor. Note the successor's |
| 548 | // live_in will not be computed yet for backwards edges. |
| 549 | HBasicBlock* successor = it.Current(); |
| 550 | BitVector* live_in = live_in_sets_[successor->block_id()]; |
| 551 | if (live_in != NULL) live_out->Union(*live_in); |
| 552 | |
| 553 | // All phi input operands corresponding to this successor edge are live |
| 554 | // out from this block. |
| 555 | int index = successor->PredecessorIndexOf(block); |
| 556 | const ZoneList<HPhi*>* phis = successor->phis(); |
| 557 | for (int i = 0; i < phis->length(); ++i) { |
| 558 | HPhi* phi = phis->at(i); |
| 559 | if (!phi->OperandAt(index)->IsConstant()) { |
| 560 | live_out->Add(phi->OperandAt(index)->id()); |
| 561 | } |
| 562 | } |
| 563 | } |
| 564 | |
| 565 | return live_out; |
| 566 | } |
| 567 | |
| 568 | |
| 569 | void LAllocator::AddInitialIntervals(HBasicBlock* block, |
| 570 | BitVector* live_out) { |
| 571 | // Add an interval that includes the entire block to the live range for |
| 572 | // each live_out value. |
| 573 | LifetimePosition start = LifetimePosition::FromInstructionIndex( |
| 574 | block->first_instruction_index()); |
| 575 | LifetimePosition end = LifetimePosition::FromInstructionIndex( |
| 576 | block->last_instruction_index()).NextInstruction(); |
| 577 | BitVector::Iterator iterator(live_out); |
| 578 | while (!iterator.Done()) { |
| 579 | int operand_index = iterator.Current(); |
| 580 | LiveRange* range = LiveRangeFor(operand_index); |
| 581 | range->AddUseInterval(start, end, zone()); |
| 582 | iterator.Advance(); |
| 583 | } |
| 584 | } |
| 585 | |
| 586 | |
| 587 | int LAllocator::FixedDoubleLiveRangeID(int index) { |
| 588 | return -index - 1 - Register::kNumRegisters; |
| 589 | } |
| 590 | |
| 591 | |
| 592 | LOperand* LAllocator::AllocateFixed(LUnallocated* operand, |
| 593 | int pos, |
| 594 | bool is_tagged) { |
| 595 | TraceAlloc("Allocating fixed reg for op %d\n", operand->virtual_register()); |
| 596 | DCHECK(operand->HasFixedPolicy()); |
| 597 | if (operand->HasFixedSlotPolicy()) { |
| 598 | operand->ConvertTo(LOperand::STACK_SLOT, operand->fixed_slot_index()); |
| 599 | } else if (operand->HasFixedRegisterPolicy()) { |
| 600 | int reg_index = operand->fixed_register_index(); |
| 601 | operand->ConvertTo(LOperand::REGISTER, reg_index); |
| 602 | } else if (operand->HasFixedDoubleRegisterPolicy()) { |
| 603 | int reg_index = operand->fixed_register_index(); |
| 604 | operand->ConvertTo(LOperand::DOUBLE_REGISTER, reg_index); |
| 605 | } else { |
| 606 | UNREACHABLE(); |
| 607 | } |
| 608 | if (is_tagged) { |
| 609 | TraceAlloc("Fixed reg is tagged at %d\n", pos); |
| 610 | LInstruction* instr = InstructionAt(pos); |
| 611 | if (instr->HasPointerMap()) { |
| 612 | instr->pointer_map()->RecordPointer(operand, chunk()->zone()); |
| 613 | } |
| 614 | } |
| 615 | return operand; |
| 616 | } |
| 617 | |
| 618 | |
| 619 | LiveRange* LAllocator::FixedLiveRangeFor(int index) { |
| 620 | DCHECK(index < Register::kNumRegisters); |
| 621 | LiveRange* result = fixed_live_ranges_[index]; |
| 622 | if (result == NULL) { |
| 623 | result = new(zone()) LiveRange(FixedLiveRangeID(index), chunk()->zone()); |
| 624 | DCHECK(result->IsFixed()); |
| 625 | result->kind_ = GENERAL_REGISTERS; |
| 626 | SetLiveRangeAssignedRegister(result, index); |
| 627 | fixed_live_ranges_[index] = result; |
| 628 | } |
| 629 | return result; |
| 630 | } |
| 631 | |
| 632 | |
| 633 | LiveRange* LAllocator::FixedDoubleLiveRangeFor(int index) { |
| 634 | DCHECK(index < DoubleRegister::kMaxNumRegisters); |
| 635 | LiveRange* result = fixed_double_live_ranges_[index]; |
| 636 | if (result == NULL) { |
| 637 | result = new(zone()) LiveRange(FixedDoubleLiveRangeID(index), |
| 638 | chunk()->zone()); |
| 639 | DCHECK(result->IsFixed()); |
| 640 | result->kind_ = DOUBLE_REGISTERS; |
| 641 | SetLiveRangeAssignedRegister(result, index); |
| 642 | fixed_double_live_ranges_[index] = result; |
| 643 | } |
| 644 | return result; |
| 645 | } |
| 646 | |
| 647 | |
| 648 | LiveRange* LAllocator::LiveRangeFor(int index) { |
| 649 | if (index >= live_ranges_.length()) { |
| 650 | live_ranges_.AddBlock(NULL, index - live_ranges_.length() + 1, zone()); |
| 651 | } |
| 652 | LiveRange* result = live_ranges_[index]; |
| 653 | if (result == NULL) { |
| 654 | result = new(zone()) LiveRange(index, chunk()->zone()); |
| 655 | live_ranges_[index] = result; |
| 656 | } |
| 657 | return result; |
| 658 | } |
| 659 | |
| 660 | |
| 661 | LGap* LAllocator::GetLastGap(HBasicBlock* block) { |
| 662 | int last_instruction = block->last_instruction_index(); |
| 663 | int index = chunk_->NearestGapPos(last_instruction); |
| 664 | return GapAt(index); |
| 665 | } |
| 666 | |
| 667 | |
| 668 | HPhi* LAllocator::LookupPhi(LOperand* operand) const { |
| 669 | if (!operand->IsUnallocated()) return NULL; |
| 670 | int index = LUnallocated::cast(operand)->virtual_register(); |
| 671 | HValue* instr = graph_->LookupValue(index); |
| 672 | if (instr != NULL && instr->IsPhi()) { |
| 673 | return HPhi::cast(instr); |
| 674 | } |
| 675 | return NULL; |
| 676 | } |
| 677 | |
| 678 | |
| 679 | LiveRange* LAllocator::LiveRangeFor(LOperand* operand) { |
| 680 | if (operand->IsUnallocated()) { |
| 681 | return LiveRangeFor(LUnallocated::cast(operand)->virtual_register()); |
| 682 | } else if (operand->IsRegister()) { |
| 683 | return FixedLiveRangeFor(operand->index()); |
| 684 | } else if (operand->IsDoubleRegister()) { |
| 685 | return FixedDoubleLiveRangeFor(operand->index()); |
| 686 | } else { |
| 687 | return NULL; |
| 688 | } |
| 689 | } |
| 690 | |
| 691 | |
| 692 | void LAllocator::Define(LifetimePosition position, |
| 693 | LOperand* operand, |
| 694 | LOperand* hint) { |
| 695 | LiveRange* range = LiveRangeFor(operand); |
| 696 | if (range == NULL) return; |
| 697 | |
| 698 | if (range->IsEmpty() || range->Start().Value() > position.Value()) { |
| 699 | // Can happen if there is a definition without use. |
| 700 | range->AddUseInterval(position, position.NextInstruction(), zone()); |
| 701 | range->AddUsePosition(position.NextInstruction(), NULL, NULL, zone()); |
| 702 | } else { |
| 703 | range->ShortenTo(position); |
| 704 | } |
| 705 | |
| 706 | if (operand->IsUnallocated()) { |
| 707 | LUnallocated* unalloc_operand = LUnallocated::cast(operand); |
| 708 | range->AddUsePosition(position, unalloc_operand, hint, zone()); |
| 709 | } |
| 710 | } |
| 711 | |
| 712 | |
| 713 | void LAllocator::Use(LifetimePosition block_start, |
| 714 | LifetimePosition position, |
| 715 | LOperand* operand, |
| 716 | LOperand* hint) { |
| 717 | LiveRange* range = LiveRangeFor(operand); |
| 718 | if (range == NULL) return; |
| 719 | if (operand->IsUnallocated()) { |
| 720 | LUnallocated* unalloc_operand = LUnallocated::cast(operand); |
| 721 | range->AddUsePosition(position, unalloc_operand, hint, zone()); |
| 722 | } |
| 723 | range->AddUseInterval(block_start, position, zone()); |
| 724 | } |
| 725 | |
| 726 | |
| 727 | void LAllocator::AddConstraintsGapMove(int index, |
| 728 | LOperand* from, |
| 729 | LOperand* to) { |
| 730 | LGap* gap = GapAt(index); |
| 731 | LParallelMove* move = gap->GetOrCreateParallelMove(LGap::START, |
| 732 | chunk()->zone()); |
| 733 | if (from->IsUnallocated()) { |
| 734 | const ZoneList<LMoveOperands>* move_operands = move->move_operands(); |
| 735 | for (int i = 0; i < move_operands->length(); ++i) { |
| 736 | LMoveOperands cur = move_operands->at(i); |
| 737 | LOperand* cur_to = cur.destination(); |
| 738 | if (cur_to->IsUnallocated()) { |
| 739 | if (LUnallocated::cast(cur_to)->virtual_register() == |
| 740 | LUnallocated::cast(from)->virtual_register()) { |
| 741 | move->AddMove(cur.source(), to, chunk()->zone()); |
| 742 | return; |
| 743 | } |
| 744 | } |
| 745 | } |
| 746 | } |
| 747 | move->AddMove(from, to, chunk()->zone()); |
| 748 | } |
| 749 | |
| 750 | |
| 751 | void LAllocator::MeetRegisterConstraints(HBasicBlock* block) { |
| 752 | int start = block->first_instruction_index(); |
| 753 | int end = block->last_instruction_index(); |
| 754 | if (start == -1) return; |
| 755 | for (int i = start; i <= end; ++i) { |
| 756 | if (IsGapAt(i)) { |
| 757 | LInstruction* instr = NULL; |
| 758 | LInstruction* prev_instr = NULL; |
| 759 | if (i < end) instr = InstructionAt(i + 1); |
| 760 | if (i > start) prev_instr = InstructionAt(i - 1); |
| 761 | MeetConstraintsBetween(prev_instr, instr, i); |
| 762 | if (!AllocationOk()) return; |
| 763 | } |
| 764 | } |
| 765 | } |
| 766 | |
| 767 | |
| 768 | void LAllocator::MeetConstraintsBetween(LInstruction* first, |
| 769 | LInstruction* second, |
| 770 | int gap_index) { |
| 771 | // Handle fixed temporaries. |
| 772 | if (first != NULL) { |
| 773 | for (TempIterator it(first); !it.Done(); it.Advance()) { |
| 774 | LUnallocated* temp = LUnallocated::cast(it.Current()); |
| 775 | if (temp->HasFixedPolicy()) { |
| 776 | AllocateFixed(temp, gap_index - 1, false); |
| 777 | } |
| 778 | } |
| 779 | } |
| 780 | |
| 781 | // Handle fixed output operand. |
| 782 | if (first != NULL && first->Output() != NULL) { |
| 783 | LUnallocated* first_output = LUnallocated::cast(first->Output()); |
| 784 | LiveRange* range = LiveRangeFor(first_output->virtual_register()); |
| 785 | bool assigned = false; |
| 786 | if (first_output->HasFixedPolicy()) { |
| 787 | LUnallocated* output_copy = first_output->CopyUnconstrained( |
| 788 | chunk()->zone()); |
| 789 | bool is_tagged = HasTaggedValue(first_output->virtual_register()); |
| 790 | AllocateFixed(first_output, gap_index, is_tagged); |
| 791 | |
| 792 | // This value is produced on the stack, we never need to spill it. |
| 793 | if (first_output->IsStackSlot()) { |
| 794 | range->SetSpillOperand(first_output); |
| 795 | range->SetSpillStartIndex(gap_index - 1); |
| 796 | assigned = true; |
| 797 | } |
| 798 | chunk_->AddGapMove(gap_index, first_output, output_copy); |
| 799 | } |
| 800 | |
| 801 | if (!assigned) { |
| 802 | range->SetSpillStartIndex(gap_index); |
| 803 | |
| 804 | // This move to spill operand is not a real use. Liveness analysis |
| 805 | // and splitting of live ranges do not account for it. |
| 806 | // Thus it should be inserted to a lifetime position corresponding to |
| 807 | // the instruction end. |
| 808 | LGap* gap = GapAt(gap_index); |
| 809 | LParallelMove* move = gap->GetOrCreateParallelMove(LGap::BEFORE, |
| 810 | chunk()->zone()); |
| 811 | move->AddMove(first_output, range->GetSpillOperand(), |
| 812 | chunk()->zone()); |
| 813 | } |
| 814 | } |
| 815 | |
| 816 | // Handle fixed input operands of second instruction. |
| 817 | if (second != NULL) { |
| 818 | for (UseIterator it(second); !it.Done(); it.Advance()) { |
| 819 | LUnallocated* cur_input = LUnallocated::cast(it.Current()); |
| 820 | if (cur_input->HasFixedPolicy()) { |
| 821 | LUnallocated* input_copy = cur_input->CopyUnconstrained( |
| 822 | chunk()->zone()); |
| 823 | bool is_tagged = HasTaggedValue(cur_input->virtual_register()); |
| 824 | AllocateFixed(cur_input, gap_index + 1, is_tagged); |
| 825 | AddConstraintsGapMove(gap_index, input_copy, cur_input); |
| 826 | } else if (cur_input->HasWritableRegisterPolicy()) { |
| 827 | // The live range of writable input registers always goes until the end |
| 828 | // of the instruction. |
| 829 | DCHECK(!cur_input->IsUsedAtStart()); |
| 830 | |
| 831 | LUnallocated* input_copy = cur_input->CopyUnconstrained( |
| 832 | chunk()->zone()); |
| 833 | int vreg = GetVirtualRegister(); |
| 834 | if (!AllocationOk()) return; |
| 835 | cur_input->set_virtual_register(vreg); |
| 836 | |
| 837 | if (RequiredRegisterKind(input_copy->virtual_register()) == |
| 838 | DOUBLE_REGISTERS) { |
| 839 | double_artificial_registers_.Add( |
| 840 | cur_input->virtual_register() - first_artificial_register_, |
| 841 | zone()); |
| 842 | } |
| 843 | |
| 844 | AddConstraintsGapMove(gap_index, input_copy, cur_input); |
| 845 | } |
| 846 | } |
| 847 | } |
| 848 | |
| 849 | // Handle "output same as input" for second instruction. |
| 850 | if (second != NULL && second->Output() != NULL) { |
| 851 | LUnallocated* second_output = LUnallocated::cast(second->Output()); |
| 852 | if (second_output->HasSameAsInputPolicy()) { |
| 853 | LUnallocated* cur_input = LUnallocated::cast(second->FirstInput()); |
| 854 | int output_vreg = second_output->virtual_register(); |
| 855 | int input_vreg = cur_input->virtual_register(); |
| 856 | |
| 857 | LUnallocated* input_copy = cur_input->CopyUnconstrained( |
| 858 | chunk()->zone()); |
| 859 | cur_input->set_virtual_register(second_output->virtual_register()); |
| 860 | AddConstraintsGapMove(gap_index, input_copy, cur_input); |
| 861 | |
| 862 | if (HasTaggedValue(input_vreg) && !HasTaggedValue(output_vreg)) { |
| 863 | int index = gap_index + 1; |
| 864 | LInstruction* instr = InstructionAt(index); |
| 865 | if (instr->HasPointerMap()) { |
| 866 | instr->pointer_map()->RecordPointer(input_copy, chunk()->zone()); |
| 867 | } |
| 868 | } else if (!HasTaggedValue(input_vreg) && HasTaggedValue(output_vreg)) { |
| 869 | // The input is assumed to immediately have a tagged representation, |
| 870 | // before the pointer map can be used. I.e. the pointer map at the |
| 871 | // instruction will include the output operand (whose value at the |
| 872 | // beginning of the instruction is equal to the input operand). If |
| 873 | // this is not desired, then the pointer map at this instruction needs |
| 874 | // to be adjusted manually. |
| 875 | } |
| 876 | } |
| 877 | } |
| 878 | } |
| 879 | |
| 880 | |
| 881 | void LAllocator::ProcessInstructions(HBasicBlock* block, BitVector* live) { |
| 882 | int block_start = block->first_instruction_index(); |
| 883 | int index = block->last_instruction_index(); |
| 884 | |
| 885 | LifetimePosition block_start_position = |
| 886 | LifetimePosition::FromInstructionIndex(block_start); |
| 887 | |
| 888 | while (index >= block_start) { |
| 889 | LifetimePosition curr_position = |
| 890 | LifetimePosition::FromInstructionIndex(index); |
| 891 | |
| 892 | if (IsGapAt(index)) { |
| 893 | // We have a gap at this position. |
| 894 | LGap* gap = GapAt(index); |
| 895 | LParallelMove* move = gap->GetOrCreateParallelMove(LGap::START, |
| 896 | chunk()->zone()); |
| 897 | const ZoneList<LMoveOperands>* move_operands = move->move_operands(); |
| 898 | for (int i = 0; i < move_operands->length(); ++i) { |
| 899 | LMoveOperands* cur = &move_operands->at(i); |
| 900 | if (cur->IsIgnored()) continue; |
| 901 | LOperand* from = cur->source(); |
| 902 | LOperand* to = cur->destination(); |
| 903 | HPhi* phi = LookupPhi(to); |
| 904 | LOperand* hint = to; |
| 905 | if (phi != NULL) { |
| 906 | // This is a phi resolving move. |
| 907 | if (!phi->block()->IsLoopHeader()) { |
| 908 | hint = LiveRangeFor(phi->id())->current_hint_operand(); |
| 909 | } |
| 910 | } else { |
| 911 | if (to->IsUnallocated()) { |
| 912 | if (live->Contains(LUnallocated::cast(to)->virtual_register())) { |
| 913 | Define(curr_position, to, from); |
| 914 | live->Remove(LUnallocated::cast(to)->virtual_register()); |
| 915 | } else { |
| 916 | cur->Eliminate(); |
| 917 | continue; |
| 918 | } |
| 919 | } else { |
| 920 | Define(curr_position, to, from); |
| 921 | } |
| 922 | } |
| 923 | Use(block_start_position, curr_position, from, hint); |
| 924 | if (from->IsUnallocated()) { |
| 925 | live->Add(LUnallocated::cast(from)->virtual_register()); |
| 926 | } |
| 927 | } |
| 928 | } else { |
| 929 | DCHECK(!IsGapAt(index)); |
| 930 | LInstruction* instr = InstructionAt(index); |
| 931 | |
| 932 | if (instr != NULL) { |
| 933 | LOperand* output = instr->Output(); |
| 934 | if (output != NULL) { |
| 935 | if (output->IsUnallocated()) { |
| 936 | live->Remove(LUnallocated::cast(output)->virtual_register()); |
| 937 | } |
| 938 | Define(curr_position, output, NULL); |
| 939 | } |
| 940 | |
| 941 | if (instr->ClobbersRegisters()) { |
| 942 | for (int i = 0; i < Register::kNumRegisters; ++i) { |
| 943 | if (Register::from_code(i).IsAllocatable()) { |
| 944 | if (output == NULL || !output->IsRegister() || |
| 945 | output->index() != i) { |
| 946 | LiveRange* range = FixedLiveRangeFor(i); |
| 947 | range->AddUseInterval(curr_position, |
| 948 | curr_position.InstructionEnd(), zone()); |
| 949 | } |
| 950 | } |
| 951 | } |
| 952 | } |
| 953 | |
| 954 | if (instr->ClobbersDoubleRegisters(isolate())) { |
| 955 | for (int i = 0; i < DoubleRegister::kMaxNumRegisters; ++i) { |
| 956 | if (DoubleRegister::from_code(i).IsAllocatable()) { |
| 957 | if (output == NULL || !output->IsDoubleRegister() || |
| 958 | output->index() != i) { |
| 959 | LiveRange* range = FixedDoubleLiveRangeFor(i); |
| 960 | range->AddUseInterval(curr_position, |
| 961 | curr_position.InstructionEnd(), zone()); |
| 962 | } |
| 963 | } |
| 964 | } |
| 965 | } |
| 966 | |
| 967 | for (UseIterator it(instr); !it.Done(); it.Advance()) { |
| 968 | LOperand* input = it.Current(); |
| 969 | |
| 970 | LifetimePosition use_pos; |
| 971 | if (input->IsUnallocated() && |
| 972 | LUnallocated::cast(input)->IsUsedAtStart()) { |
| 973 | use_pos = curr_position; |
| 974 | } else { |
| 975 | use_pos = curr_position.InstructionEnd(); |
| 976 | } |
| 977 | |
| 978 | Use(block_start_position, use_pos, input, NULL); |
| 979 | if (input->IsUnallocated()) { |
| 980 | live->Add(LUnallocated::cast(input)->virtual_register()); |
| 981 | } |
| 982 | } |
| 983 | |
| 984 | for (TempIterator it(instr); !it.Done(); it.Advance()) { |
| 985 | LOperand* temp = it.Current(); |
| 986 | if (instr->ClobbersTemps()) { |
| 987 | if (temp->IsRegister()) continue; |
| 988 | if (temp->IsUnallocated()) { |
| 989 | LUnallocated* temp_unalloc = LUnallocated::cast(temp); |
| 990 | if (temp_unalloc->HasFixedPolicy()) { |
| 991 | continue; |
| 992 | } |
| 993 | } |
| 994 | } |
| 995 | Use(block_start_position, curr_position.InstructionEnd(), temp, NULL); |
| 996 | Define(curr_position, temp, NULL); |
| 997 | |
| 998 | if (temp->IsUnallocated()) { |
| 999 | LUnallocated* temp_unalloc = LUnallocated::cast(temp); |
| 1000 | if (temp_unalloc->HasDoubleRegisterPolicy()) { |
| 1001 | double_artificial_registers_.Add( |
| 1002 | temp_unalloc->virtual_register() - first_artificial_register_, |
| 1003 | zone()); |
| 1004 | } |
| 1005 | } |
| 1006 | } |
| 1007 | } |
| 1008 | } |
| 1009 | |
| 1010 | index = index - 1; |
| 1011 | } |
| 1012 | } |
| 1013 | |
| 1014 | |
| 1015 | void LAllocator::ResolvePhis(HBasicBlock* block) { |
| 1016 | const ZoneList<HPhi*>* phis = block->phis(); |
| 1017 | for (int i = 0; i < phis->length(); ++i) { |
| 1018 | HPhi* phi = phis->at(i); |
| 1019 | LUnallocated* phi_operand = |
| 1020 | new (chunk()->zone()) LUnallocated(LUnallocated::NONE); |
| 1021 | phi_operand->set_virtual_register(phi->id()); |
| 1022 | for (int j = 0; j < phi->OperandCount(); ++j) { |
| 1023 | HValue* op = phi->OperandAt(j); |
| 1024 | LOperand* operand = NULL; |
| 1025 | if (op->IsConstant() && op->EmitAtUses()) { |
| 1026 | HConstant* constant = HConstant::cast(op); |
| 1027 | operand = chunk_->DefineConstantOperand(constant); |
| 1028 | } else { |
| 1029 | DCHECK(!op->EmitAtUses()); |
| 1030 | LUnallocated* unalloc = |
| 1031 | new(chunk()->zone()) LUnallocated(LUnallocated::ANY); |
| 1032 | unalloc->set_virtual_register(op->id()); |
| 1033 | operand = unalloc; |
| 1034 | } |
| 1035 | HBasicBlock* cur_block = block->predecessors()->at(j); |
| 1036 | // The gap move must be added without any special processing as in |
| 1037 | // the AddConstraintsGapMove. |
| 1038 | chunk_->AddGapMove(cur_block->last_instruction_index() - 1, |
| 1039 | operand, |
| 1040 | phi_operand); |
| 1041 | |
| 1042 | // We are going to insert a move before the branch instruction. |
| 1043 | // Some branch instructions (e.g. loops' back edges) |
| 1044 | // can potentially cause a GC so they have a pointer map. |
| 1045 | // By inserting a move we essentially create a copy of a |
| 1046 | // value which is invisible to PopulatePointerMaps(), because we store |
| 1047 | // it into a location different from the operand of a live range |
| 1048 | // covering a branch instruction. |
| 1049 | // Thus we need to manually record a pointer. |
| 1050 | LInstruction* branch = |
| 1051 | InstructionAt(cur_block->last_instruction_index()); |
| 1052 | if (branch->HasPointerMap()) { |
| 1053 | if (phi->representation().IsTagged() && !phi->type().IsSmi()) { |
| 1054 | branch->pointer_map()->RecordPointer(phi_operand, chunk()->zone()); |
| 1055 | } else if (!phi->representation().IsDouble()) { |
| 1056 | branch->pointer_map()->RecordUntagged(phi_operand, chunk()->zone()); |
| 1057 | } |
| 1058 | } |
| 1059 | } |
| 1060 | |
| 1061 | LiveRange* live_range = LiveRangeFor(phi->id()); |
| 1062 | LLabel* label = chunk_->GetLabel(phi->block()->block_id()); |
| 1063 | label->GetOrCreateParallelMove(LGap::START, chunk()->zone())-> |
| 1064 | AddMove(phi_operand, live_range->GetSpillOperand(), chunk()->zone()); |
| 1065 | live_range->SetSpillStartIndex(phi->block()->first_instruction_index()); |
| 1066 | } |
| 1067 | } |
| 1068 | |
| 1069 | |
| 1070 | bool LAllocator::Allocate(LChunk* chunk) { |
| 1071 | DCHECK(chunk_ == NULL); |
| 1072 | chunk_ = static_cast<LPlatformChunk*>(chunk); |
| 1073 | assigned_registers_ = |
| 1074 | new (chunk->zone()) BitVector(Register::kNumRegisters, chunk->zone()); |
| 1075 | assigned_double_registers_ = new (chunk->zone()) |
| 1076 | BitVector(DoubleRegister::kMaxNumRegisters, chunk->zone()); |
| 1077 | MeetRegisterConstraints(); |
| 1078 | if (!AllocationOk()) return false; |
| 1079 | ResolvePhis(); |
| 1080 | BuildLiveRanges(); |
| 1081 | AllocateGeneralRegisters(); |
| 1082 | if (!AllocationOk()) return false; |
| 1083 | AllocateDoubleRegisters(); |
| 1084 | if (!AllocationOk()) return false; |
| 1085 | PopulatePointerMaps(); |
| 1086 | ConnectRanges(); |
| 1087 | ResolveControlFlow(); |
| 1088 | return true; |
| 1089 | } |
| 1090 | |
| 1091 | |
| 1092 | void LAllocator::MeetRegisterConstraints() { |
| 1093 | LAllocatorPhase phase("L_Register constraints", this); |
| 1094 | const ZoneList<HBasicBlock*>* blocks = graph_->blocks(); |
| 1095 | for (int i = 0; i < blocks->length(); ++i) { |
| 1096 | HBasicBlock* block = blocks->at(i); |
| 1097 | MeetRegisterConstraints(block); |
| 1098 | if (!AllocationOk()) return; |
| 1099 | } |
| 1100 | } |
| 1101 | |
| 1102 | |
| 1103 | void LAllocator::ResolvePhis() { |
| 1104 | LAllocatorPhase phase("L_Resolve phis", this); |
| 1105 | |
| 1106 | // Process the blocks in reverse order. |
| 1107 | const ZoneList<HBasicBlock*>* blocks = graph_->blocks(); |
| 1108 | for (int block_id = blocks->length() - 1; block_id >= 0; --block_id) { |
| 1109 | HBasicBlock* block = blocks->at(block_id); |
| 1110 | ResolvePhis(block); |
| 1111 | } |
| 1112 | } |
| 1113 | |
| 1114 | |
| 1115 | void LAllocator::ResolveControlFlow(LiveRange* range, |
| 1116 | HBasicBlock* block, |
| 1117 | HBasicBlock* pred) { |
| 1118 | LifetimePosition pred_end = |
| 1119 | LifetimePosition::FromInstructionIndex(pred->last_instruction_index()); |
| 1120 | LifetimePosition cur_start = |
| 1121 | LifetimePosition::FromInstructionIndex(block->first_instruction_index()); |
| 1122 | LiveRange* pred_cover = NULL; |
| 1123 | LiveRange* cur_cover = NULL; |
| 1124 | LiveRange* cur_range = range; |
| 1125 | while (cur_range != NULL && (cur_cover == NULL || pred_cover == NULL)) { |
| 1126 | if (cur_range->CanCover(cur_start)) { |
| 1127 | DCHECK(cur_cover == NULL); |
| 1128 | cur_cover = cur_range; |
| 1129 | } |
| 1130 | if (cur_range->CanCover(pred_end)) { |
| 1131 | DCHECK(pred_cover == NULL); |
| 1132 | pred_cover = cur_range; |
| 1133 | } |
| 1134 | cur_range = cur_range->next(); |
| 1135 | } |
| 1136 | |
| 1137 | if (cur_cover->IsSpilled()) return; |
| 1138 | DCHECK(pred_cover != NULL && cur_cover != NULL); |
| 1139 | if (pred_cover != cur_cover) { |
| 1140 | LOperand* pred_op = pred_cover->CreateAssignedOperand(chunk()->zone()); |
| 1141 | LOperand* cur_op = cur_cover->CreateAssignedOperand(chunk()->zone()); |
| 1142 | if (!pred_op->Equals(cur_op)) { |
| 1143 | LGap* gap = NULL; |
| 1144 | if (block->predecessors()->length() == 1) { |
| 1145 | gap = GapAt(block->first_instruction_index()); |
| 1146 | } else { |
| 1147 | DCHECK(pred->end()->SecondSuccessor() == NULL); |
| 1148 | gap = GetLastGap(pred); |
| 1149 | |
| 1150 | // We are going to insert a move before the branch instruction. |
| 1151 | // Some branch instructions (e.g. loops' back edges) |
| 1152 | // can potentially cause a GC so they have a pointer map. |
| 1153 | // By inserting a move we essentially create a copy of a |
| 1154 | // value which is invisible to PopulatePointerMaps(), because we store |
| 1155 | // it into a location different from the operand of a live range |
| 1156 | // covering a branch instruction. |
| 1157 | // Thus we need to manually record a pointer. |
| 1158 | LInstruction* branch = InstructionAt(pred->last_instruction_index()); |
| 1159 | if (branch->HasPointerMap()) { |
| 1160 | if (HasTaggedValue(range->id())) { |
| 1161 | branch->pointer_map()->RecordPointer(cur_op, chunk()->zone()); |
| 1162 | } else if (!cur_op->IsDoubleStackSlot() && |
| 1163 | !cur_op->IsDoubleRegister()) { |
| 1164 | branch->pointer_map()->RemovePointer(cur_op); |
| 1165 | } |
| 1166 | } |
| 1167 | } |
| 1168 | gap->GetOrCreateParallelMove( |
| 1169 | LGap::START, chunk()->zone())->AddMove(pred_op, cur_op, |
| 1170 | chunk()->zone()); |
| 1171 | } |
| 1172 | } |
| 1173 | } |
| 1174 | |
| 1175 | |
| 1176 | LParallelMove* LAllocator::GetConnectingParallelMove(LifetimePosition pos) { |
| 1177 | int index = pos.InstructionIndex(); |
| 1178 | if (IsGapAt(index)) { |
| 1179 | LGap* gap = GapAt(index); |
| 1180 | return gap->GetOrCreateParallelMove( |
| 1181 | pos.IsInstructionStart() ? LGap::START : LGap::END, chunk()->zone()); |
| 1182 | } |
| 1183 | int gap_pos = pos.IsInstructionStart() ? (index - 1) : (index + 1); |
| 1184 | return GapAt(gap_pos)->GetOrCreateParallelMove( |
| 1185 | (gap_pos < index) ? LGap::AFTER : LGap::BEFORE, chunk()->zone()); |
| 1186 | } |
| 1187 | |
| 1188 | |
| 1189 | HBasicBlock* LAllocator::GetBlock(LifetimePosition pos) { |
| 1190 | LGap* gap = GapAt(chunk_->NearestGapPos(pos.InstructionIndex())); |
| 1191 | return gap->block(); |
| 1192 | } |
| 1193 | |
| 1194 | |
| 1195 | void LAllocator::ConnectRanges() { |
| 1196 | LAllocatorPhase phase("L_Connect ranges", this); |
| 1197 | for (int i = 0; i < live_ranges()->length(); ++i) { |
| 1198 | LiveRange* first_range = live_ranges()->at(i); |
| 1199 | if (first_range == NULL || first_range->parent() != NULL) continue; |
| 1200 | |
| 1201 | LiveRange* second_range = first_range->next(); |
| 1202 | while (second_range != NULL) { |
| 1203 | LifetimePosition pos = second_range->Start(); |
| 1204 | |
| 1205 | if (!second_range->IsSpilled()) { |
| 1206 | // Add gap move if the two live ranges touch and there is no block |
| 1207 | // boundary. |
| 1208 | if (first_range->End().Value() == pos.Value()) { |
| 1209 | bool should_insert = true; |
| 1210 | if (IsBlockBoundary(pos)) { |
| 1211 | should_insert = CanEagerlyResolveControlFlow(GetBlock(pos)); |
| 1212 | } |
| 1213 | if (should_insert) { |
| 1214 | LParallelMove* move = GetConnectingParallelMove(pos); |
| 1215 | LOperand* prev_operand = first_range->CreateAssignedOperand( |
| 1216 | chunk()->zone()); |
| 1217 | LOperand* cur_operand = second_range->CreateAssignedOperand( |
| 1218 | chunk()->zone()); |
| 1219 | move->AddMove(prev_operand, cur_operand, |
| 1220 | chunk()->zone()); |
| 1221 | } |
| 1222 | } |
| 1223 | } |
| 1224 | |
| 1225 | first_range = second_range; |
| 1226 | second_range = second_range->next(); |
| 1227 | } |
| 1228 | } |
| 1229 | } |
| 1230 | |
| 1231 | |
| 1232 | bool LAllocator::CanEagerlyResolveControlFlow(HBasicBlock* block) const { |
| 1233 | if (block->predecessors()->length() != 1) return false; |
| 1234 | return block->predecessors()->first()->block_id() == block->block_id() - 1; |
| 1235 | } |
| 1236 | |
| 1237 | |
| 1238 | void LAllocator::ResolveControlFlow() { |
| 1239 | LAllocatorPhase phase("L_Resolve control flow", this); |
| 1240 | const ZoneList<HBasicBlock*>* blocks = graph_->blocks(); |
| 1241 | for (int block_id = 1; block_id < blocks->length(); ++block_id) { |
| 1242 | HBasicBlock* block = blocks->at(block_id); |
| 1243 | if (CanEagerlyResolveControlFlow(block)) continue; |
| 1244 | BitVector* live = live_in_sets_[block->block_id()]; |
| 1245 | BitVector::Iterator iterator(live); |
| 1246 | while (!iterator.Done()) { |
| 1247 | int operand_index = iterator.Current(); |
| 1248 | for (int i = 0; i < block->predecessors()->length(); ++i) { |
| 1249 | HBasicBlock* cur = block->predecessors()->at(i); |
| 1250 | LiveRange* cur_range = LiveRangeFor(operand_index); |
| 1251 | ResolveControlFlow(cur_range, block, cur); |
| 1252 | } |
| 1253 | iterator.Advance(); |
| 1254 | } |
| 1255 | } |
| 1256 | } |
| 1257 | |
| 1258 | |
| 1259 | void LAllocator::BuildLiveRanges() { |
| 1260 | LAllocatorPhase phase("L_Build live ranges", this); |
| 1261 | InitializeLivenessAnalysis(); |
| 1262 | // Process the blocks in reverse order. |
| 1263 | const ZoneList<HBasicBlock*>* blocks = graph_->blocks(); |
| 1264 | for (int block_id = blocks->length() - 1; block_id >= 0; --block_id) { |
| 1265 | HBasicBlock* block = blocks->at(block_id); |
| 1266 | BitVector* live = ComputeLiveOut(block); |
| 1267 | // Initially consider all live_out values live for the entire block. We |
| 1268 | // will shorten these intervals if necessary. |
| 1269 | AddInitialIntervals(block, live); |
| 1270 | |
| 1271 | // Process the instructions in reverse order, generating and killing |
| 1272 | // live values. |
| 1273 | ProcessInstructions(block, live); |
| 1274 | // All phi output operands are killed by this block. |
| 1275 | const ZoneList<HPhi*>* phis = block->phis(); |
| 1276 | for (int i = 0; i < phis->length(); ++i) { |
| 1277 | // The live range interval already ends at the first instruction of the |
| 1278 | // block. |
| 1279 | HPhi* phi = phis->at(i); |
| 1280 | live->Remove(phi->id()); |
| 1281 | |
| 1282 | LOperand* hint = NULL; |
| 1283 | LOperand* phi_operand = NULL; |
| 1284 | LGap* gap = GetLastGap(phi->block()->predecessors()->at(0)); |
| 1285 | LParallelMove* move = gap->GetOrCreateParallelMove(LGap::START, |
| 1286 | chunk()->zone()); |
| 1287 | for (int j = 0; j < move->move_operands()->length(); ++j) { |
| 1288 | LOperand* to = move->move_operands()->at(j).destination(); |
| 1289 | if (to->IsUnallocated() && |
| 1290 | LUnallocated::cast(to)->virtual_register() == phi->id()) { |
| 1291 | hint = move->move_operands()->at(j).source(); |
| 1292 | phi_operand = to; |
| 1293 | break; |
| 1294 | } |
| 1295 | } |
| 1296 | DCHECK(hint != NULL); |
| 1297 | |
| 1298 | LifetimePosition block_start = LifetimePosition::FromInstructionIndex( |
| 1299 | block->first_instruction_index()); |
| 1300 | Define(block_start, phi_operand, hint); |
| 1301 | } |
| 1302 | |
| 1303 | // Now live is live_in for this block except not including values live |
| 1304 | // out on backward successor edges. |
| 1305 | live_in_sets_[block_id] = live; |
| 1306 | |
| 1307 | // If this block is a loop header go back and patch up the necessary |
| 1308 | // predecessor blocks. |
| 1309 | if (block->IsLoopHeader()) { |
| 1310 | // TODO(kmillikin): Need to be able to get the last block of the loop |
| 1311 | // in the loop information. Add a live range stretching from the first |
| 1312 | // loop instruction to the last for each value live on entry to the |
| 1313 | // header. |
| 1314 | HBasicBlock* back_edge = block->loop_information()->GetLastBackEdge(); |
| 1315 | BitVector::Iterator iterator(live); |
| 1316 | LifetimePosition start = LifetimePosition::FromInstructionIndex( |
| 1317 | block->first_instruction_index()); |
| 1318 | LifetimePosition end = LifetimePosition::FromInstructionIndex( |
| 1319 | back_edge->last_instruction_index()).NextInstruction(); |
| 1320 | while (!iterator.Done()) { |
| 1321 | int operand_index = iterator.Current(); |
| 1322 | LiveRange* range = LiveRangeFor(operand_index); |
| 1323 | range->EnsureInterval(start, end, zone()); |
| 1324 | iterator.Advance(); |
| 1325 | } |
| 1326 | |
| 1327 | for (int i = block->block_id() + 1; i <= back_edge->block_id(); ++i) { |
| 1328 | live_in_sets_[i]->Union(*live); |
| 1329 | } |
| 1330 | } |
| 1331 | |
| 1332 | #ifdef DEBUG |
| 1333 | if (block_id == 0) { |
| 1334 | BitVector::Iterator iterator(live); |
| 1335 | bool found = false; |
| 1336 | while (!iterator.Done()) { |
| 1337 | found = true; |
| 1338 | int operand_index = iterator.Current(); |
| 1339 | { |
| 1340 | AllowHandleDereference allow_deref; |
| 1341 | PrintF("Function: %s\n", chunk_->info()->GetDebugName().get()); |
| 1342 | } |
| 1343 | PrintF("Value %d used before first definition!\n", operand_index); |
| 1344 | LiveRange* range = LiveRangeFor(operand_index); |
| 1345 | PrintF("First use is at %d\n", range->first_pos()->pos().Value()); |
| 1346 | iterator.Advance(); |
| 1347 | } |
| 1348 | DCHECK(!found); |
| 1349 | } |
| 1350 | #endif |
| 1351 | } |
| 1352 | |
| 1353 | for (int i = 0; i < live_ranges_.length(); ++i) { |
| 1354 | if (live_ranges_[i] != NULL) { |
| 1355 | live_ranges_[i]->kind_ = RequiredRegisterKind(live_ranges_[i]->id()); |
| 1356 | } |
| 1357 | } |
| 1358 | } |
| 1359 | |
| 1360 | |
| 1361 | bool LAllocator::SafePointsAreInOrder() const { |
| 1362 | const ZoneList<LPointerMap*>* pointer_maps = chunk_->pointer_maps(); |
| 1363 | int safe_point = 0; |
| 1364 | for (int i = 0; i < pointer_maps->length(); ++i) { |
| 1365 | LPointerMap* map = pointer_maps->at(i); |
| 1366 | if (safe_point > map->lithium_position()) return false; |
| 1367 | safe_point = map->lithium_position(); |
| 1368 | } |
| 1369 | return true; |
| 1370 | } |
| 1371 | |
| 1372 | |
| 1373 | void LAllocator::PopulatePointerMaps() { |
| 1374 | LAllocatorPhase phase("L_Populate pointer maps", this); |
| 1375 | const ZoneList<LPointerMap*>* pointer_maps = chunk_->pointer_maps(); |
| 1376 | |
| 1377 | DCHECK(SafePointsAreInOrder()); |
| 1378 | |
| 1379 | // Iterate over all safe point positions and record a pointer |
| 1380 | // for all spilled live ranges at this point. |
| 1381 | int first_safe_point_index = 0; |
| 1382 | int last_range_start = 0; |
| 1383 | for (int range_idx = 0; range_idx < live_ranges()->length(); ++range_idx) { |
| 1384 | LiveRange* range = live_ranges()->at(range_idx); |
| 1385 | if (range == NULL) continue; |
| 1386 | // Iterate over the first parts of multi-part live ranges. |
| 1387 | if (range->parent() != NULL) continue; |
| 1388 | // Skip non-pointer values. |
| 1389 | if (!HasTaggedValue(range->id())) continue; |
| 1390 | // Skip empty live ranges. |
| 1391 | if (range->IsEmpty()) continue; |
| 1392 | |
| 1393 | // Find the extent of the range and its children. |
| 1394 | int start = range->Start().InstructionIndex(); |
| 1395 | int end = 0; |
| 1396 | for (LiveRange* cur = range; cur != NULL; cur = cur->next()) { |
| 1397 | LifetimePosition this_end = cur->End(); |
| 1398 | if (this_end.InstructionIndex() > end) end = this_end.InstructionIndex(); |
| 1399 | DCHECK(cur->Start().InstructionIndex() >= start); |
| 1400 | } |
| 1401 | |
| 1402 | // Most of the ranges are in order, but not all. Keep an eye on when |
| 1403 | // they step backwards and reset the first_safe_point_index so we don't |
| 1404 | // miss any safe points. |
| 1405 | if (start < last_range_start) { |
| 1406 | first_safe_point_index = 0; |
| 1407 | } |
| 1408 | last_range_start = start; |
| 1409 | |
| 1410 | // Step across all the safe points that are before the start of this range, |
| 1411 | // recording how far we step in order to save doing this for the next range. |
| 1412 | while (first_safe_point_index < pointer_maps->length()) { |
| 1413 | LPointerMap* map = pointer_maps->at(first_safe_point_index); |
| 1414 | int safe_point = map->lithium_position(); |
| 1415 | if (safe_point >= start) break; |
| 1416 | first_safe_point_index++; |
| 1417 | } |
| 1418 | |
| 1419 | // Step through the safe points to see whether they are in the range. |
| 1420 | for (int safe_point_index = first_safe_point_index; |
| 1421 | safe_point_index < pointer_maps->length(); |
| 1422 | ++safe_point_index) { |
| 1423 | LPointerMap* map = pointer_maps->at(safe_point_index); |
| 1424 | int safe_point = map->lithium_position(); |
| 1425 | |
| 1426 | // The safe points are sorted so we can stop searching here. |
| 1427 | if (safe_point - 1 > end) break; |
| 1428 | |
| 1429 | // Advance to the next active range that covers the current |
| 1430 | // safe point position. |
| 1431 | LifetimePosition safe_point_pos = |
| 1432 | LifetimePosition::FromInstructionIndex(safe_point); |
| 1433 | LiveRange* cur = range; |
| 1434 | while (cur != NULL && !cur->Covers(safe_point_pos)) { |
| 1435 | cur = cur->next(); |
| 1436 | } |
| 1437 | if (cur == NULL) continue; |
| 1438 | |
| 1439 | // Check if the live range is spilled and the safe point is after |
| 1440 | // the spill position. |
| 1441 | if (range->HasAllocatedSpillOperand() && |
| 1442 | safe_point >= range->spill_start_index()) { |
| 1443 | TraceAlloc("Pointer for range %d (spilled at %d) at safe point %d\n", |
| 1444 | range->id(), range->spill_start_index(), safe_point); |
| 1445 | map->RecordPointer(range->GetSpillOperand(), chunk()->zone()); |
| 1446 | } |
| 1447 | |
| 1448 | if (!cur->IsSpilled()) { |
| 1449 | TraceAlloc("Pointer in register for range %d (start at %d) " |
| 1450 | "at safe point %d\n", |
| 1451 | cur->id(), cur->Start().Value(), safe_point); |
| 1452 | LOperand* operand = cur->CreateAssignedOperand(chunk()->zone()); |
| 1453 | DCHECK(!operand->IsStackSlot()); |
| 1454 | map->RecordPointer(operand, chunk()->zone()); |
| 1455 | } |
| 1456 | } |
| 1457 | } |
| 1458 | } |
| 1459 | |
| 1460 | |
| 1461 | void LAllocator::AllocateGeneralRegisters() { |
| 1462 | LAllocatorPhase phase("L_Allocate general registers", this); |
| 1463 | num_registers_ = |
| 1464 | RegisterConfiguration::ArchDefault(RegisterConfiguration::CRANKSHAFT) |
| 1465 | ->num_allocatable_general_registers(); |
| 1466 | allocatable_register_codes_ = |
| 1467 | RegisterConfiguration::ArchDefault(RegisterConfiguration::CRANKSHAFT) |
| 1468 | ->allocatable_general_codes(); |
| 1469 | mode_ = GENERAL_REGISTERS; |
| 1470 | AllocateRegisters(); |
| 1471 | } |
| 1472 | |
| 1473 | |
| 1474 | void LAllocator::AllocateDoubleRegisters() { |
| 1475 | LAllocatorPhase phase("L_Allocate double registers", this); |
| 1476 | num_registers_ = |
| 1477 | RegisterConfiguration::ArchDefault(RegisterConfiguration::CRANKSHAFT) |
| 1478 | ->num_allocatable_double_registers(); |
| 1479 | allocatable_register_codes_ = |
| 1480 | RegisterConfiguration::ArchDefault(RegisterConfiguration::CRANKSHAFT) |
| 1481 | ->allocatable_double_codes(); |
| 1482 | mode_ = DOUBLE_REGISTERS; |
| 1483 | AllocateRegisters(); |
| 1484 | } |
| 1485 | |
| 1486 | |
| 1487 | void LAllocator::AllocateRegisters() { |
| 1488 | DCHECK(unhandled_live_ranges_.is_empty()); |
| 1489 | |
| 1490 | for (int i = 0; i < live_ranges_.length(); ++i) { |
| 1491 | if (live_ranges_[i] != NULL) { |
| 1492 | if (live_ranges_[i]->Kind() == mode_) { |
| 1493 | AddToUnhandledUnsorted(live_ranges_[i]); |
| 1494 | } |
| 1495 | } |
| 1496 | } |
| 1497 | SortUnhandled(); |
| 1498 | DCHECK(UnhandledIsSorted()); |
| 1499 | |
| 1500 | DCHECK(reusable_slots_.is_empty()); |
| 1501 | DCHECK(active_live_ranges_.is_empty()); |
| 1502 | DCHECK(inactive_live_ranges_.is_empty()); |
| 1503 | |
| 1504 | if (mode_ == DOUBLE_REGISTERS) { |
| 1505 | for (int i = 0; i < fixed_double_live_ranges_.length(); ++i) { |
| 1506 | LiveRange* current = fixed_double_live_ranges_.at(i); |
| 1507 | if (current != NULL) { |
| 1508 | AddToInactive(current); |
| 1509 | } |
| 1510 | } |
| 1511 | } else { |
| 1512 | DCHECK(mode_ == GENERAL_REGISTERS); |
| 1513 | for (int i = 0; i < fixed_live_ranges_.length(); ++i) { |
| 1514 | LiveRange* current = fixed_live_ranges_.at(i); |
| 1515 | if (current != NULL) { |
| 1516 | AddToInactive(current); |
| 1517 | } |
| 1518 | } |
| 1519 | } |
| 1520 | |
| 1521 | while (!unhandled_live_ranges_.is_empty()) { |
| 1522 | DCHECK(UnhandledIsSorted()); |
| 1523 | LiveRange* current = unhandled_live_ranges_.RemoveLast(); |
| 1524 | DCHECK(UnhandledIsSorted()); |
| 1525 | LifetimePosition position = current->Start(); |
| 1526 | #ifdef DEBUG |
| 1527 | allocation_finger_ = position; |
| 1528 | #endif |
| 1529 | TraceAlloc("Processing interval %d start=%d\n", |
| 1530 | current->id(), |
| 1531 | position.Value()); |
| 1532 | |
| 1533 | if (current->HasAllocatedSpillOperand()) { |
| 1534 | TraceAlloc("Live range %d already has a spill operand\n", current->id()); |
| 1535 | LifetimePosition next_pos = position; |
| 1536 | if (IsGapAt(next_pos.InstructionIndex())) { |
| 1537 | next_pos = next_pos.NextInstruction(); |
| 1538 | } |
| 1539 | UsePosition* pos = current->NextUsePositionRegisterIsBeneficial(next_pos); |
| 1540 | // If the range already has a spill operand and it doesn't need a |
| 1541 | // register immediately, split it and spill the first part of the range. |
| 1542 | if (pos == NULL) { |
| 1543 | Spill(current); |
| 1544 | continue; |
| 1545 | } else if (pos->pos().Value() > |
| 1546 | current->Start().NextInstruction().Value()) { |
| 1547 | // Do not spill live range eagerly if use position that can benefit from |
| 1548 | // the register is too close to the start of live range. |
| 1549 | SpillBetween(current, current->Start(), pos->pos()); |
| 1550 | if (!AllocationOk()) return; |
| 1551 | DCHECK(UnhandledIsSorted()); |
| 1552 | continue; |
| 1553 | } |
| 1554 | } |
| 1555 | |
| 1556 | for (int i = 0; i < active_live_ranges_.length(); ++i) { |
| 1557 | LiveRange* cur_active = active_live_ranges_.at(i); |
| 1558 | if (cur_active->End().Value() <= position.Value()) { |
| 1559 | ActiveToHandled(cur_active); |
| 1560 | --i; // The live range was removed from the list of active live ranges. |
| 1561 | } else if (!cur_active->Covers(position)) { |
| 1562 | ActiveToInactive(cur_active); |
| 1563 | --i; // The live range was removed from the list of active live ranges. |
| 1564 | } |
| 1565 | } |
| 1566 | |
| 1567 | for (int i = 0; i < inactive_live_ranges_.length(); ++i) { |
| 1568 | LiveRange* cur_inactive = inactive_live_ranges_.at(i); |
| 1569 | if (cur_inactive->End().Value() <= position.Value()) { |
| 1570 | InactiveToHandled(cur_inactive); |
| 1571 | --i; // Live range was removed from the list of inactive live ranges. |
| 1572 | } else if (cur_inactive->Covers(position)) { |
| 1573 | InactiveToActive(cur_inactive); |
| 1574 | --i; // Live range was removed from the list of inactive live ranges. |
| 1575 | } |
| 1576 | } |
| 1577 | |
| 1578 | DCHECK(!current->HasRegisterAssigned() && !current->IsSpilled()); |
| 1579 | |
| 1580 | bool result = TryAllocateFreeReg(current); |
| 1581 | if (!AllocationOk()) return; |
| 1582 | |
| 1583 | if (!result) AllocateBlockedReg(current); |
| 1584 | if (!AllocationOk()) return; |
| 1585 | |
| 1586 | if (current->HasRegisterAssigned()) { |
| 1587 | AddToActive(current); |
| 1588 | } |
| 1589 | } |
| 1590 | |
| 1591 | reusable_slots_.Rewind(0); |
| 1592 | active_live_ranges_.Rewind(0); |
| 1593 | inactive_live_ranges_.Rewind(0); |
| 1594 | } |
| 1595 | |
| 1596 | |
| 1597 | const char* LAllocator::RegisterName(int allocation_index) { |
| 1598 | if (mode_ == GENERAL_REGISTERS) { |
| 1599 | return Register::from_code(allocation_index).ToString(); |
| 1600 | } else { |
| 1601 | return DoubleRegister::from_code(allocation_index).ToString(); |
| 1602 | } |
| 1603 | } |
| 1604 | |
| 1605 | |
| 1606 | void LAllocator::TraceAlloc(const char* msg, ...) { |
| 1607 | if (FLAG_trace_alloc) { |
| 1608 | va_list arguments; |
| 1609 | va_start(arguments, msg); |
| 1610 | base::OS::VPrint(msg, arguments); |
| 1611 | va_end(arguments); |
| 1612 | } |
| 1613 | } |
| 1614 | |
| 1615 | |
| 1616 | bool LAllocator::HasTaggedValue(int virtual_register) const { |
| 1617 | HValue* value = graph_->LookupValue(virtual_register); |
| 1618 | if (value == NULL) return false; |
| 1619 | return value->representation().IsTagged() && !value->type().IsSmi(); |
| 1620 | } |
| 1621 | |
| 1622 | |
| 1623 | RegisterKind LAllocator::RequiredRegisterKind(int virtual_register) const { |
| 1624 | if (virtual_register < first_artificial_register_) { |
| 1625 | HValue* value = graph_->LookupValue(virtual_register); |
| 1626 | if (value != NULL && value->representation().IsDouble()) { |
| 1627 | return DOUBLE_REGISTERS; |
| 1628 | } |
| 1629 | } else if (double_artificial_registers_.Contains( |
| 1630 | virtual_register - first_artificial_register_)) { |
| 1631 | return DOUBLE_REGISTERS; |
| 1632 | } |
| 1633 | |
| 1634 | return GENERAL_REGISTERS; |
| 1635 | } |
| 1636 | |
| 1637 | |
| 1638 | void LAllocator::AddToActive(LiveRange* range) { |
| 1639 | TraceAlloc("Add live range %d to active\n", range->id()); |
| 1640 | active_live_ranges_.Add(range, zone()); |
| 1641 | } |
| 1642 | |
| 1643 | |
| 1644 | void LAllocator::AddToInactive(LiveRange* range) { |
| 1645 | TraceAlloc("Add live range %d to inactive\n", range->id()); |
| 1646 | inactive_live_ranges_.Add(range, zone()); |
| 1647 | } |
| 1648 | |
| 1649 | |
| 1650 | void LAllocator::AddToUnhandledSorted(LiveRange* range) { |
| 1651 | if (range == NULL || range->IsEmpty()) return; |
| 1652 | DCHECK(!range->HasRegisterAssigned() && !range->IsSpilled()); |
| 1653 | DCHECK(allocation_finger_.Value() <= range->Start().Value()); |
| 1654 | for (int i = unhandled_live_ranges_.length() - 1; i >= 0; --i) { |
| 1655 | LiveRange* cur_range = unhandled_live_ranges_.at(i); |
| 1656 | if (range->ShouldBeAllocatedBefore(cur_range)) { |
| 1657 | TraceAlloc("Add live range %d to unhandled at %d\n", range->id(), i + 1); |
| 1658 | unhandled_live_ranges_.InsertAt(i + 1, range, zone()); |
| 1659 | DCHECK(UnhandledIsSorted()); |
| 1660 | return; |
| 1661 | } |
| 1662 | } |
| 1663 | TraceAlloc("Add live range %d to unhandled at start\n", range->id()); |
| 1664 | unhandled_live_ranges_.InsertAt(0, range, zone()); |
| 1665 | DCHECK(UnhandledIsSorted()); |
| 1666 | } |
| 1667 | |
| 1668 | |
| 1669 | void LAllocator::AddToUnhandledUnsorted(LiveRange* range) { |
| 1670 | if (range == NULL || range->IsEmpty()) return; |
| 1671 | DCHECK(!range->HasRegisterAssigned() && !range->IsSpilled()); |
| 1672 | TraceAlloc("Add live range %d to unhandled unsorted at end\n", range->id()); |
| 1673 | unhandled_live_ranges_.Add(range, zone()); |
| 1674 | } |
| 1675 | |
| 1676 | |
| 1677 | static int UnhandledSortHelper(LiveRange* const* a, LiveRange* const* b) { |
| 1678 | DCHECK(!(*a)->ShouldBeAllocatedBefore(*b) || |
| 1679 | !(*b)->ShouldBeAllocatedBefore(*a)); |
| 1680 | if ((*a)->ShouldBeAllocatedBefore(*b)) return 1; |
| 1681 | if ((*b)->ShouldBeAllocatedBefore(*a)) return -1; |
| 1682 | return (*a)->id() - (*b)->id(); |
| 1683 | } |
| 1684 | |
| 1685 | |
| 1686 | // Sort the unhandled live ranges so that the ranges to be processed first are |
| 1687 | // at the end of the array list. This is convenient for the register allocation |
| 1688 | // algorithm because it is efficient to remove elements from the end. |
| 1689 | void LAllocator::SortUnhandled() { |
| 1690 | TraceAlloc("Sort unhandled\n"); |
| 1691 | unhandled_live_ranges_.Sort(&UnhandledSortHelper); |
| 1692 | } |
| 1693 | |
| 1694 | |
| 1695 | bool LAllocator::UnhandledIsSorted() { |
| 1696 | int len = unhandled_live_ranges_.length(); |
| 1697 | for (int i = 1; i < len; i++) { |
| 1698 | LiveRange* a = unhandled_live_ranges_.at(i - 1); |
| 1699 | LiveRange* b = unhandled_live_ranges_.at(i); |
| 1700 | if (a->Start().Value() < b->Start().Value()) return false; |
| 1701 | } |
| 1702 | return true; |
| 1703 | } |
| 1704 | |
| 1705 | |
| 1706 | void LAllocator::FreeSpillSlot(LiveRange* range) { |
| 1707 | // Check that we are the last range. |
| 1708 | if (range->next() != NULL) return; |
| 1709 | |
| 1710 | if (!range->TopLevel()->HasAllocatedSpillOperand()) return; |
| 1711 | |
| 1712 | int index = range->TopLevel()->GetSpillOperand()->index(); |
| 1713 | if (index >= 0) { |
| 1714 | reusable_slots_.Add(range, zone()); |
| 1715 | } |
| 1716 | } |
| 1717 | |
| 1718 | |
| 1719 | LOperand* LAllocator::TryReuseSpillSlot(LiveRange* range) { |
| 1720 | if (reusable_slots_.is_empty()) return NULL; |
| 1721 | if (reusable_slots_.first()->End().Value() > |
| 1722 | range->TopLevel()->Start().Value()) { |
| 1723 | return NULL; |
| 1724 | } |
| 1725 | LOperand* result = reusable_slots_.first()->TopLevel()->GetSpillOperand(); |
| 1726 | reusable_slots_.Remove(0); |
| 1727 | return result; |
| 1728 | } |
| 1729 | |
| 1730 | |
| 1731 | void LAllocator::ActiveToHandled(LiveRange* range) { |
| 1732 | DCHECK(active_live_ranges_.Contains(range)); |
| 1733 | active_live_ranges_.RemoveElement(range); |
| 1734 | TraceAlloc("Moving live range %d from active to handled\n", range->id()); |
| 1735 | FreeSpillSlot(range); |
| 1736 | } |
| 1737 | |
| 1738 | |
| 1739 | void LAllocator::ActiveToInactive(LiveRange* range) { |
| 1740 | DCHECK(active_live_ranges_.Contains(range)); |
| 1741 | active_live_ranges_.RemoveElement(range); |
| 1742 | inactive_live_ranges_.Add(range, zone()); |
| 1743 | TraceAlloc("Moving live range %d from active to inactive\n", range->id()); |
| 1744 | } |
| 1745 | |
| 1746 | |
| 1747 | void LAllocator::InactiveToHandled(LiveRange* range) { |
| 1748 | DCHECK(inactive_live_ranges_.Contains(range)); |
| 1749 | inactive_live_ranges_.RemoveElement(range); |
| 1750 | TraceAlloc("Moving live range %d from inactive to handled\n", range->id()); |
| 1751 | FreeSpillSlot(range); |
| 1752 | } |
| 1753 | |
| 1754 | |
| 1755 | void LAllocator::InactiveToActive(LiveRange* range) { |
| 1756 | DCHECK(inactive_live_ranges_.Contains(range)); |
| 1757 | inactive_live_ranges_.RemoveElement(range); |
| 1758 | active_live_ranges_.Add(range, zone()); |
| 1759 | TraceAlloc("Moving live range %d from inactive to active\n", range->id()); |
| 1760 | } |
| 1761 | |
| 1762 | |
| 1763 | bool LAllocator::TryAllocateFreeReg(LiveRange* current) { |
| 1764 | DCHECK(DoubleRegister::kMaxNumRegisters >= Register::kNumRegisters); |
| 1765 | |
| 1766 | LifetimePosition free_until_pos[DoubleRegister::kMaxNumRegisters]; |
| 1767 | |
| 1768 | for (int i = 0; i < DoubleRegister::kMaxNumRegisters; i++) { |
| 1769 | free_until_pos[i] = LifetimePosition::MaxPosition(); |
| 1770 | } |
| 1771 | |
| 1772 | for (int i = 0; i < active_live_ranges_.length(); ++i) { |
| 1773 | LiveRange* cur_active = active_live_ranges_.at(i); |
| 1774 | free_until_pos[cur_active->assigned_register()] = |
| 1775 | LifetimePosition::FromInstructionIndex(0); |
| 1776 | } |
| 1777 | |
| 1778 | for (int i = 0; i < inactive_live_ranges_.length(); ++i) { |
| 1779 | LiveRange* cur_inactive = inactive_live_ranges_.at(i); |
| 1780 | DCHECK(cur_inactive->End().Value() > current->Start().Value()); |
| 1781 | LifetimePosition next_intersection = |
| 1782 | cur_inactive->FirstIntersection(current); |
| 1783 | if (!next_intersection.IsValid()) continue; |
| 1784 | int cur_reg = cur_inactive->assigned_register(); |
| 1785 | free_until_pos[cur_reg] = Min(free_until_pos[cur_reg], next_intersection); |
| 1786 | } |
| 1787 | |
| 1788 | LOperand* hint = current->FirstHint(); |
| 1789 | if (hint != NULL && (hint->IsRegister() || hint->IsDoubleRegister())) { |
| 1790 | int register_index = hint->index(); |
| 1791 | TraceAlloc( |
| 1792 | "Found reg hint %s (free until [%d) for live range %d (end %d[).\n", |
| 1793 | RegisterName(register_index), |
| 1794 | free_until_pos[register_index].Value(), |
| 1795 | current->id(), |
| 1796 | current->End().Value()); |
| 1797 | |
| 1798 | // The desired register is free until the end of the current live range. |
| 1799 | if (free_until_pos[register_index].Value() >= current->End().Value()) { |
| 1800 | TraceAlloc("Assigning preferred reg %s to live range %d\n", |
| 1801 | RegisterName(register_index), |
| 1802 | current->id()); |
| 1803 | SetLiveRangeAssignedRegister(current, register_index); |
| 1804 | return true; |
| 1805 | } |
| 1806 | } |
| 1807 | |
| 1808 | // Find the register which stays free for the longest time. |
| 1809 | int reg = allocatable_register_codes_[0]; |
| 1810 | for (int i = 1; i < RegisterCount(); ++i) { |
| 1811 | int code = allocatable_register_codes_[i]; |
| 1812 | if (free_until_pos[code].Value() > free_until_pos[reg].Value()) { |
| 1813 | reg = code; |
| 1814 | } |
| 1815 | } |
| 1816 | |
| 1817 | LifetimePosition pos = free_until_pos[reg]; |
| 1818 | |
| 1819 | if (pos.Value() <= current->Start().Value()) { |
| 1820 | // All registers are blocked. |
| 1821 | return false; |
| 1822 | } |
| 1823 | |
| 1824 | if (pos.Value() < current->End().Value()) { |
| 1825 | // Register reg is available at the range start but becomes blocked before |
| 1826 | // the range end. Split current at position where it becomes blocked. |
| 1827 | LiveRange* tail = SplitRangeAt(current, pos); |
| 1828 | if (!AllocationOk()) return false; |
| 1829 | AddToUnhandledSorted(tail); |
| 1830 | } |
| 1831 | |
| 1832 | |
| 1833 | // Register reg is available at the range start and is free until |
| 1834 | // the range end. |
| 1835 | DCHECK(pos.Value() >= current->End().Value()); |
| 1836 | TraceAlloc("Assigning free reg %s to live range %d\n", |
| 1837 | RegisterName(reg), |
| 1838 | current->id()); |
| 1839 | SetLiveRangeAssignedRegister(current, reg); |
| 1840 | |
| 1841 | return true; |
| 1842 | } |
| 1843 | |
| 1844 | |
| 1845 | void LAllocator::AllocateBlockedReg(LiveRange* current) { |
| 1846 | UsePosition* register_use = current->NextRegisterPosition(current->Start()); |
| 1847 | if (register_use == NULL) { |
| 1848 | // There is no use in the current live range that requires a register. |
| 1849 | // We can just spill it. |
| 1850 | Spill(current); |
| 1851 | return; |
| 1852 | } |
| 1853 | |
| 1854 | |
| 1855 | LifetimePosition use_pos[DoubleRegister::kMaxNumRegisters]; |
| 1856 | LifetimePosition block_pos[DoubleRegister::kMaxNumRegisters]; |
| 1857 | |
| 1858 | for (int i = 0; i < DoubleRegister::kMaxNumRegisters; i++) { |
| 1859 | use_pos[i] = block_pos[i] = LifetimePosition::MaxPosition(); |
| 1860 | } |
| 1861 | |
| 1862 | for (int i = 0; i < active_live_ranges_.length(); ++i) { |
| 1863 | LiveRange* range = active_live_ranges_[i]; |
| 1864 | int cur_reg = range->assigned_register(); |
| 1865 | if (range->IsFixed() || !range->CanBeSpilled(current->Start())) { |
| 1866 | block_pos[cur_reg] = use_pos[cur_reg] = |
| 1867 | LifetimePosition::FromInstructionIndex(0); |
| 1868 | } else { |
| 1869 | UsePosition* next_use = range->NextUsePositionRegisterIsBeneficial( |
| 1870 | current->Start()); |
| 1871 | if (next_use == NULL) { |
| 1872 | use_pos[cur_reg] = range->End(); |
| 1873 | } else { |
| 1874 | use_pos[cur_reg] = next_use->pos(); |
| 1875 | } |
| 1876 | } |
| 1877 | } |
| 1878 | |
| 1879 | for (int i = 0; i < inactive_live_ranges_.length(); ++i) { |
| 1880 | LiveRange* range = inactive_live_ranges_.at(i); |
| 1881 | DCHECK(range->End().Value() > current->Start().Value()); |
| 1882 | LifetimePosition next_intersection = range->FirstIntersection(current); |
| 1883 | if (!next_intersection.IsValid()) continue; |
| 1884 | int cur_reg = range->assigned_register(); |
| 1885 | if (range->IsFixed()) { |
| 1886 | block_pos[cur_reg] = Min(block_pos[cur_reg], next_intersection); |
| 1887 | use_pos[cur_reg] = Min(block_pos[cur_reg], use_pos[cur_reg]); |
| 1888 | } else { |
| 1889 | use_pos[cur_reg] = Min(use_pos[cur_reg], next_intersection); |
| 1890 | } |
| 1891 | } |
| 1892 | |
| 1893 | int reg = allocatable_register_codes_[0]; |
| 1894 | for (int i = 1; i < RegisterCount(); ++i) { |
| 1895 | int code = allocatable_register_codes_[i]; |
| 1896 | if (use_pos[code].Value() > use_pos[reg].Value()) { |
| 1897 | reg = code; |
| 1898 | } |
| 1899 | } |
| 1900 | |
| 1901 | LifetimePosition pos = use_pos[reg]; |
| 1902 | |
| 1903 | if (pos.Value() < register_use->pos().Value()) { |
| 1904 | // All registers are blocked before the first use that requires a register. |
| 1905 | // Spill starting part of live range up to that use. |
| 1906 | SpillBetween(current, current->Start(), register_use->pos()); |
| 1907 | return; |
| 1908 | } |
| 1909 | |
| 1910 | if (block_pos[reg].Value() < current->End().Value()) { |
| 1911 | // Register becomes blocked before the current range end. Split before that |
| 1912 | // position. |
| 1913 | LiveRange* tail = SplitBetween(current, |
| 1914 | current->Start(), |
| 1915 | block_pos[reg].InstructionStart()); |
| 1916 | if (!AllocationOk()) return; |
| 1917 | AddToUnhandledSorted(tail); |
| 1918 | } |
| 1919 | |
| 1920 | // Register reg is not blocked for the whole range. |
| 1921 | DCHECK(block_pos[reg].Value() >= current->End().Value()); |
| 1922 | TraceAlloc("Assigning blocked reg %s to live range %d\n", |
| 1923 | RegisterName(reg), |
| 1924 | current->id()); |
| 1925 | SetLiveRangeAssignedRegister(current, reg); |
| 1926 | |
| 1927 | // This register was not free. Thus we need to find and spill |
| 1928 | // parts of active and inactive live regions that use the same register |
| 1929 | // at the same lifetime positions as current. |
| 1930 | SplitAndSpillIntersecting(current); |
| 1931 | } |
| 1932 | |
| 1933 | |
| 1934 | LifetimePosition LAllocator::FindOptimalSpillingPos(LiveRange* range, |
| 1935 | LifetimePosition pos) { |
| 1936 | HBasicBlock* block = GetBlock(pos.InstructionStart()); |
| 1937 | HBasicBlock* loop_header = |
| 1938 | block->IsLoopHeader() ? block : block->parent_loop_header(); |
| 1939 | |
| 1940 | if (loop_header == NULL) return pos; |
| 1941 | |
| 1942 | UsePosition* prev_use = |
| 1943 | range->PreviousUsePositionRegisterIsBeneficial(pos); |
| 1944 | |
| 1945 | while (loop_header != NULL) { |
| 1946 | // We are going to spill live range inside the loop. |
| 1947 | // If possible try to move spilling position backwards to loop header. |
| 1948 | // This will reduce number of memory moves on the back edge. |
| 1949 | LifetimePosition loop_start = LifetimePosition::FromInstructionIndex( |
| 1950 | loop_header->first_instruction_index()); |
| 1951 | |
| 1952 | if (range->Covers(loop_start)) { |
| 1953 | if (prev_use == NULL || prev_use->pos().Value() < loop_start.Value()) { |
| 1954 | // No register beneficial use inside the loop before the pos. |
| 1955 | pos = loop_start; |
| 1956 | } |
| 1957 | } |
| 1958 | |
| 1959 | // Try hoisting out to an outer loop. |
| 1960 | loop_header = loop_header->parent_loop_header(); |
| 1961 | } |
| 1962 | |
| 1963 | return pos; |
| 1964 | } |
| 1965 | |
| 1966 | |
| 1967 | void LAllocator::SplitAndSpillIntersecting(LiveRange* current) { |
| 1968 | DCHECK(current->HasRegisterAssigned()); |
| 1969 | int reg = current->assigned_register(); |
| 1970 | LifetimePosition split_pos = current->Start(); |
| 1971 | for (int i = 0; i < active_live_ranges_.length(); ++i) { |
| 1972 | LiveRange* range = active_live_ranges_[i]; |
| 1973 | if (range->assigned_register() == reg) { |
| 1974 | UsePosition* next_pos = range->NextRegisterPosition(current->Start()); |
| 1975 | LifetimePosition spill_pos = FindOptimalSpillingPos(range, split_pos); |
| 1976 | if (next_pos == NULL) { |
| 1977 | SpillAfter(range, spill_pos); |
| 1978 | } else { |
| 1979 | // When spilling between spill_pos and next_pos ensure that the range |
| 1980 | // remains spilled at least until the start of the current live range. |
| 1981 | // This guarantees that we will not introduce new unhandled ranges that |
| 1982 | // start before the current range as this violates allocation invariant |
| 1983 | // and will lead to an inconsistent state of active and inactive |
| 1984 | // live-ranges: ranges are allocated in order of their start positions, |
| 1985 | // ranges are retired from active/inactive when the start of the |
| 1986 | // current live-range is larger than their end. |
| 1987 | SpillBetweenUntil(range, spill_pos, current->Start(), next_pos->pos()); |
| 1988 | } |
| 1989 | if (!AllocationOk()) return; |
| 1990 | ActiveToHandled(range); |
| 1991 | --i; |
| 1992 | } |
| 1993 | } |
| 1994 | |
| 1995 | for (int i = 0; i < inactive_live_ranges_.length(); ++i) { |
| 1996 | LiveRange* range = inactive_live_ranges_[i]; |
| 1997 | DCHECK(range->End().Value() > current->Start().Value()); |
| 1998 | if (range->assigned_register() == reg && !range->IsFixed()) { |
| 1999 | LifetimePosition next_intersection = range->FirstIntersection(current); |
| 2000 | if (next_intersection.IsValid()) { |
| 2001 | UsePosition* next_pos = range->NextRegisterPosition(current->Start()); |
| 2002 | if (next_pos == NULL) { |
| 2003 | SpillAfter(range, split_pos); |
| 2004 | } else { |
| 2005 | next_intersection = Min(next_intersection, next_pos->pos()); |
| 2006 | SpillBetween(range, split_pos, next_intersection); |
| 2007 | } |
| 2008 | if (!AllocationOk()) return; |
| 2009 | InactiveToHandled(range); |
| 2010 | --i; |
| 2011 | } |
| 2012 | } |
| 2013 | } |
| 2014 | } |
| 2015 | |
| 2016 | |
| 2017 | bool LAllocator::IsBlockBoundary(LifetimePosition pos) { |
| 2018 | return pos.IsInstructionStart() && |
| 2019 | InstructionAt(pos.InstructionIndex())->IsLabel(); |
| 2020 | } |
| 2021 | |
| 2022 | |
| 2023 | LiveRange* LAllocator::SplitRangeAt(LiveRange* range, LifetimePosition pos) { |
| 2024 | DCHECK(!range->IsFixed()); |
| 2025 | TraceAlloc("Splitting live range %d at %d\n", range->id(), pos.Value()); |
| 2026 | |
| 2027 | if (pos.Value() <= range->Start().Value()) return range; |
| 2028 | |
| 2029 | // We can't properly connect liveranges if split occured at the end |
| 2030 | // of control instruction. |
| 2031 | DCHECK(pos.IsInstructionStart() || |
| 2032 | !chunk_->instructions()->at(pos.InstructionIndex())->IsControl()); |
| 2033 | |
| 2034 | int vreg = GetVirtualRegister(); |
| 2035 | if (!AllocationOk()) return NULL; |
| 2036 | LiveRange* result = LiveRangeFor(vreg); |
| 2037 | range->SplitAt(pos, result, zone()); |
| 2038 | return result; |
| 2039 | } |
| 2040 | |
| 2041 | |
| 2042 | LiveRange* LAllocator::SplitBetween(LiveRange* range, |
| 2043 | LifetimePosition start, |
| 2044 | LifetimePosition end) { |
| 2045 | DCHECK(!range->IsFixed()); |
| 2046 | TraceAlloc("Splitting live range %d in position between [%d, %d]\n", |
| 2047 | range->id(), |
| 2048 | start.Value(), |
| 2049 | end.Value()); |
| 2050 | |
| 2051 | LifetimePosition split_pos = FindOptimalSplitPos(start, end); |
| 2052 | DCHECK(split_pos.Value() >= start.Value()); |
| 2053 | return SplitRangeAt(range, split_pos); |
| 2054 | } |
| 2055 | |
| 2056 | |
| 2057 | LifetimePosition LAllocator::FindOptimalSplitPos(LifetimePosition start, |
| 2058 | LifetimePosition end) { |
| 2059 | int start_instr = start.InstructionIndex(); |
| 2060 | int end_instr = end.InstructionIndex(); |
| 2061 | DCHECK(start_instr <= end_instr); |
| 2062 | |
| 2063 | // We have no choice |
| 2064 | if (start_instr == end_instr) return end; |
| 2065 | |
| 2066 | HBasicBlock* start_block = GetBlock(start); |
| 2067 | HBasicBlock* end_block = GetBlock(end); |
| 2068 | |
| 2069 | if (end_block == start_block) { |
| 2070 | // The interval is split in the same basic block. Split at the latest |
| 2071 | // possible position. |
| 2072 | return end; |
| 2073 | } |
| 2074 | |
| 2075 | HBasicBlock* block = end_block; |
| 2076 | // Find header of outermost loop. |
| 2077 | while (block->parent_loop_header() != NULL && |
| 2078 | block->parent_loop_header()->block_id() > start_block->block_id()) { |
| 2079 | block = block->parent_loop_header(); |
| 2080 | } |
| 2081 | |
| 2082 | // We did not find any suitable outer loop. Split at the latest possible |
| 2083 | // position unless end_block is a loop header itself. |
| 2084 | if (block == end_block && !end_block->IsLoopHeader()) return end; |
| 2085 | |
| 2086 | return LifetimePosition::FromInstructionIndex( |
| 2087 | block->first_instruction_index()); |
| 2088 | } |
| 2089 | |
| 2090 | |
| 2091 | void LAllocator::SpillAfter(LiveRange* range, LifetimePosition pos) { |
| 2092 | LiveRange* second_part = SplitRangeAt(range, pos); |
| 2093 | if (!AllocationOk()) return; |
| 2094 | Spill(second_part); |
| 2095 | } |
| 2096 | |
| 2097 | |
| 2098 | void LAllocator::SpillBetween(LiveRange* range, |
| 2099 | LifetimePosition start, |
| 2100 | LifetimePosition end) { |
| 2101 | SpillBetweenUntil(range, start, start, end); |
| 2102 | } |
| 2103 | |
| 2104 | |
| 2105 | void LAllocator::SpillBetweenUntil(LiveRange* range, |
| 2106 | LifetimePosition start, |
| 2107 | LifetimePosition until, |
| 2108 | LifetimePosition end) { |
| 2109 | CHECK(start.Value() < end.Value()); |
| 2110 | LiveRange* second_part = SplitRangeAt(range, start); |
| 2111 | if (!AllocationOk()) return; |
| 2112 | |
| 2113 | if (second_part->Start().Value() < end.Value()) { |
| 2114 | // The split result intersects with [start, end[. |
| 2115 | // Split it at position between ]start+1, end[, spill the middle part |
| 2116 | // and put the rest to unhandled. |
| 2117 | LiveRange* third_part = SplitBetween( |
| 2118 | second_part, |
| 2119 | Max(second_part->Start().InstructionEnd(), until), |
| 2120 | end.PrevInstruction().InstructionEnd()); |
| 2121 | if (!AllocationOk()) return; |
| 2122 | |
| 2123 | DCHECK(third_part != second_part); |
| 2124 | |
| 2125 | Spill(second_part); |
| 2126 | AddToUnhandledSorted(third_part); |
| 2127 | } else { |
| 2128 | // The split result does not intersect with [start, end[. |
| 2129 | // Nothing to spill. Just put it to unhandled as whole. |
| 2130 | AddToUnhandledSorted(second_part); |
| 2131 | } |
| 2132 | } |
| 2133 | |
| 2134 | |
| 2135 | void LAllocator::Spill(LiveRange* range) { |
| 2136 | DCHECK(!range->IsSpilled()); |
| 2137 | TraceAlloc("Spilling live range %d\n", range->id()); |
| 2138 | LiveRange* first = range->TopLevel(); |
| 2139 | |
| 2140 | if (!first->HasAllocatedSpillOperand()) { |
| 2141 | LOperand* op = TryReuseSpillSlot(range); |
| 2142 | if (op == NULL) op = chunk_->GetNextSpillSlot(range->Kind()); |
| 2143 | first->SetSpillOperand(op); |
| 2144 | } |
| 2145 | range->MakeSpilled(chunk()->zone()); |
| 2146 | } |
| 2147 | |
| 2148 | |
| 2149 | int LAllocator::RegisterCount() const { |
| 2150 | return num_registers_; |
| 2151 | } |
| 2152 | |
| 2153 | |
| 2154 | #ifdef DEBUG |
| 2155 | |
| 2156 | |
| 2157 | void LAllocator::Verify() const { |
| 2158 | for (int i = 0; i < live_ranges()->length(); ++i) { |
| 2159 | LiveRange* current = live_ranges()->at(i); |
| 2160 | if (current != NULL) current->Verify(); |
| 2161 | } |
| 2162 | } |
| 2163 | |
| 2164 | |
| 2165 | #endif |
| 2166 | |
| 2167 | |
| 2168 | LAllocatorPhase::LAllocatorPhase(const char* name, LAllocator* allocator) |
| 2169 | : CompilationPhase(name, allocator->graph()->info()), |
| 2170 | allocator_(allocator) { |
| 2171 | if (FLAG_hydrogen_stats) { |
| 2172 | allocator_zone_start_allocation_size_ = |
| 2173 | allocator->zone()->allocation_size(); |
| 2174 | } |
| 2175 | } |
| 2176 | |
| 2177 | |
| 2178 | LAllocatorPhase::~LAllocatorPhase() { |
| 2179 | if (FLAG_hydrogen_stats) { |
| 2180 | size_t size = allocator_->zone()->allocation_size() - |
| 2181 | allocator_zone_start_allocation_size_; |
| 2182 | isolate()->GetHStatistics()->SaveTiming(name(), base::TimeDelta(), size); |
| 2183 | } |
| 2184 | |
| 2185 | if (ShouldProduceTraceOutput()) { |
| 2186 | isolate()->GetHTracer()->TraceLithium(name(), allocator_->chunk()); |
| 2187 | isolate()->GetHTracer()->TraceLiveRanges(name(), allocator_); |
| 2188 | } |
| 2189 | |
| 2190 | #ifdef DEBUG |
| 2191 | if (allocator_ != NULL) allocator_->Verify(); |
| 2192 | #endif |
| 2193 | } |
| 2194 | |
| 2195 | |
| 2196 | } // namespace internal |
| 2197 | } // namespace v8 |