Ben Murdoch | b0fe162 | 2011-05-05 13:52:32 +0100 | [diff] [blame] | 1 | // Copyright 2010 the V8 project authors. All rights reserved. |
| 2 | // Redistribution and use in source and binary forms, with or without |
| 3 | // modification, are permitted provided that the following conditions are |
| 4 | // met: |
| 5 | // |
| 6 | // * Redistributions of source code must retain the above copyright |
| 7 | // notice, this list of conditions and the following disclaimer. |
| 8 | // * Redistributions in binary form must reproduce the above |
| 9 | // copyright notice, this list of conditions and the following |
| 10 | // disclaimer in the documentation and/or other materials provided |
| 11 | // with the distribution. |
| 12 | // * Neither the name of Google Inc. nor the names of its |
| 13 | // contributors may be used to endorse or promote products derived |
| 14 | // from this software without specific prior written permission. |
| 15 | // |
| 16 | // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 17 | // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 18 | // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 19 | // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 20 | // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 21 | // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 22 | // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 23 | // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 24 | // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 25 | // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 26 | // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 27 | |
| 28 | #include "lithium-allocator.h" |
| 29 | |
Ben Murdoch | b0fe162 | 2011-05-05 13:52:32 +0100 | [diff] [blame] | 30 | #include "hydrogen.h" |
| 31 | #include "string-stream.h" |
| 32 | |
| 33 | #if V8_TARGET_ARCH_IA32 |
| 34 | #include "ia32/lithium-ia32.h" |
| 35 | #elif V8_TARGET_ARCH_X64 |
| 36 | #include "x64/lithium-x64.h" |
| 37 | #elif V8_TARGET_ARCH_ARM |
| 38 | #include "arm/lithium-arm.h" |
| 39 | #else |
| 40 | #error "Unknown architecture." |
| 41 | #endif |
| 42 | |
| 43 | namespace v8 { |
| 44 | namespace internal { |
| 45 | |
| 46 | |
| 47 | #define DEFINE_OPERAND_CACHE(name, type) \ |
| 48 | name name::cache[name::kNumCachedOperands]; \ |
| 49 | void name::SetupCache() { \ |
| 50 | for (int i = 0; i < kNumCachedOperands; i++) { \ |
| 51 | cache[i].ConvertTo(type, i); \ |
| 52 | } \ |
| 53 | } |
| 54 | |
| 55 | DEFINE_OPERAND_CACHE(LConstantOperand, CONSTANT_OPERAND) |
| 56 | DEFINE_OPERAND_CACHE(LStackSlot, STACK_SLOT) |
| 57 | DEFINE_OPERAND_CACHE(LDoubleStackSlot, DOUBLE_STACK_SLOT) |
| 58 | DEFINE_OPERAND_CACHE(LRegister, REGISTER) |
| 59 | DEFINE_OPERAND_CACHE(LDoubleRegister, DOUBLE_REGISTER) |
| 60 | |
| 61 | #undef DEFINE_OPERAND_CACHE |
| 62 | |
| 63 | |
| 64 | static inline LifetimePosition Min(LifetimePosition a, LifetimePosition b) { |
| 65 | return a.Value() < b.Value() ? a : b; |
| 66 | } |
| 67 | |
| 68 | |
| 69 | static inline LifetimePosition Max(LifetimePosition a, LifetimePosition b) { |
| 70 | return a.Value() > b.Value() ? a : b; |
| 71 | } |
| 72 | |
| 73 | |
| 74 | void LOperand::PrintTo(StringStream* stream) { |
| 75 | LUnallocated* unalloc = NULL; |
| 76 | switch (kind()) { |
| 77 | case INVALID: |
| 78 | break; |
| 79 | case UNALLOCATED: |
| 80 | unalloc = LUnallocated::cast(this); |
| 81 | stream->Add("v%d", unalloc->virtual_register()); |
| 82 | switch (unalloc->policy()) { |
| 83 | case LUnallocated::NONE: |
| 84 | break; |
| 85 | case LUnallocated::FIXED_REGISTER: { |
| 86 | const char* register_name = |
| 87 | Register::AllocationIndexToString(unalloc->fixed_index()); |
| 88 | stream->Add("(=%s)", register_name); |
| 89 | break; |
| 90 | } |
| 91 | case LUnallocated::FIXED_DOUBLE_REGISTER: { |
| 92 | const char* double_register_name = |
| 93 | DoubleRegister::AllocationIndexToString(unalloc->fixed_index()); |
| 94 | stream->Add("(=%s)", double_register_name); |
| 95 | break; |
| 96 | } |
| 97 | case LUnallocated::FIXED_SLOT: |
| 98 | stream->Add("(=%dS)", unalloc->fixed_index()); |
| 99 | break; |
| 100 | case LUnallocated::MUST_HAVE_REGISTER: |
| 101 | stream->Add("(R)"); |
| 102 | break; |
| 103 | case LUnallocated::WRITABLE_REGISTER: |
| 104 | stream->Add("(WR)"); |
| 105 | break; |
| 106 | case LUnallocated::SAME_AS_FIRST_INPUT: |
| 107 | stream->Add("(1)"); |
| 108 | break; |
Ben Murdoch | b0fe162 | 2011-05-05 13:52:32 +0100 | [diff] [blame] | 109 | case LUnallocated::ANY: |
| 110 | stream->Add("(-)"); |
| 111 | break; |
| 112 | case LUnallocated::IGNORE: |
| 113 | stream->Add("(0)"); |
| 114 | break; |
| 115 | } |
| 116 | break; |
| 117 | case CONSTANT_OPERAND: |
| 118 | stream->Add("[constant:%d]", index()); |
| 119 | break; |
| 120 | case STACK_SLOT: |
| 121 | stream->Add("[stack:%d]", index()); |
| 122 | break; |
| 123 | case DOUBLE_STACK_SLOT: |
| 124 | stream->Add("[double_stack:%d]", index()); |
| 125 | break; |
| 126 | case REGISTER: |
| 127 | stream->Add("[%s|R]", Register::AllocationIndexToString(index())); |
| 128 | break; |
| 129 | case DOUBLE_REGISTER: |
| 130 | stream->Add("[%s|R]", DoubleRegister::AllocationIndexToString(index())); |
| 131 | break; |
| 132 | case ARGUMENT: |
| 133 | stream->Add("[arg:%d]", index()); |
| 134 | break; |
| 135 | } |
| 136 | } |
| 137 | |
| 138 | int LOperand::VirtualRegister() { |
| 139 | LUnallocated* unalloc = LUnallocated::cast(this); |
| 140 | return unalloc->virtual_register(); |
| 141 | } |
| 142 | |
| 143 | |
| 144 | bool UsePosition::RequiresRegister() const { |
| 145 | return requires_reg_; |
| 146 | } |
| 147 | |
| 148 | |
| 149 | bool UsePosition::RegisterIsBeneficial() const { |
| 150 | return register_beneficial_; |
| 151 | } |
| 152 | |
| 153 | |
| 154 | void UseInterval::SplitAt(LifetimePosition pos) { |
| 155 | ASSERT(Contains(pos) && pos.Value() != start().Value()); |
| 156 | UseInterval* after = new UseInterval(pos, end_); |
| 157 | after->next_ = next_; |
| 158 | next_ = after; |
| 159 | end_ = pos; |
| 160 | } |
| 161 | |
| 162 | |
| 163 | #ifdef DEBUG |
| 164 | |
| 165 | |
| 166 | void LiveRange::Verify() const { |
| 167 | UsePosition* cur = first_pos_; |
| 168 | while (cur != NULL) { |
| 169 | ASSERT(Start().Value() <= cur->pos().Value() && |
| 170 | cur->pos().Value() <= End().Value()); |
| 171 | cur = cur->next(); |
| 172 | } |
| 173 | } |
| 174 | |
| 175 | |
| 176 | bool LiveRange::HasOverlap(UseInterval* target) const { |
| 177 | UseInterval* current_interval = first_interval_; |
| 178 | while (current_interval != NULL) { |
| 179 | // Intervals overlap if the start of one is contained in the other. |
| 180 | if (current_interval->Contains(target->start()) || |
| 181 | target->Contains(current_interval->start())) { |
| 182 | return true; |
| 183 | } |
| 184 | current_interval = current_interval->next(); |
| 185 | } |
| 186 | return false; |
| 187 | } |
| 188 | |
| 189 | |
| 190 | #endif |
| 191 | |
| 192 | |
| 193 | UsePosition* LiveRange::NextUsePosition(LifetimePosition start) { |
| 194 | UsePosition* use_pos = last_processed_use_; |
| 195 | if (use_pos == NULL) use_pos = first_pos(); |
| 196 | while (use_pos != NULL && use_pos->pos().Value() < start.Value()) { |
| 197 | use_pos = use_pos->next(); |
| 198 | } |
| 199 | last_processed_use_ = use_pos; |
| 200 | return use_pos; |
| 201 | } |
| 202 | |
| 203 | |
| 204 | UsePosition* LiveRange::NextUsePositionRegisterIsBeneficial( |
| 205 | LifetimePosition start) { |
| 206 | UsePosition* pos = NextUsePosition(start); |
| 207 | while (pos != NULL && !pos->RegisterIsBeneficial()) { |
| 208 | pos = pos->next(); |
| 209 | } |
| 210 | return pos; |
| 211 | } |
| 212 | |
| 213 | |
| 214 | UsePosition* LiveRange::NextRegisterPosition(LifetimePosition start) { |
| 215 | UsePosition* pos = NextUsePosition(start); |
| 216 | while (pos != NULL && !pos->RequiresRegister()) { |
| 217 | pos = pos->next(); |
| 218 | } |
| 219 | return pos; |
| 220 | } |
| 221 | |
| 222 | |
| 223 | bool LiveRange::CanBeSpilled(LifetimePosition pos) { |
| 224 | // TODO(kmillikin): Comment. Now. |
| 225 | if (pos.Value() <= Start().Value() && HasRegisterAssigned()) return false; |
| 226 | |
| 227 | // We cannot spill a live range that has a use requiring a register |
| 228 | // at the current or the immediate next position. |
| 229 | UsePosition* use_pos = NextRegisterPosition(pos); |
| 230 | if (use_pos == NULL) return true; |
| 231 | return use_pos->pos().Value() > pos.NextInstruction().Value(); |
| 232 | } |
| 233 | |
| 234 | |
| 235 | UsePosition* LiveRange::FirstPosWithHint() const { |
| 236 | UsePosition* pos = first_pos_; |
| 237 | while (pos != NULL && !pos->HasHint()) pos = pos->next(); |
| 238 | return pos; |
| 239 | } |
| 240 | |
| 241 | |
| 242 | LOperand* LiveRange::CreateAssignedOperand() { |
| 243 | LOperand* op = NULL; |
| 244 | if (HasRegisterAssigned()) { |
| 245 | ASSERT(!IsSpilled()); |
| 246 | if (IsDouble()) { |
| 247 | op = LDoubleRegister::Create(assigned_register()); |
| 248 | } else { |
| 249 | op = LRegister::Create(assigned_register()); |
| 250 | } |
| 251 | } else if (IsSpilled()) { |
| 252 | ASSERT(!HasRegisterAssigned()); |
| 253 | op = TopLevel()->GetSpillOperand(); |
| 254 | ASSERT(!op->IsUnallocated()); |
| 255 | } else { |
| 256 | LUnallocated* unalloc = new LUnallocated(LUnallocated::NONE); |
| 257 | unalloc->set_virtual_register(id_); |
| 258 | op = unalloc; |
| 259 | } |
| 260 | return op; |
| 261 | } |
| 262 | |
| 263 | |
| 264 | UseInterval* LiveRange::FirstSearchIntervalForPosition( |
| 265 | LifetimePosition position) const { |
| 266 | if (current_interval_ == NULL) return first_interval_; |
| 267 | if (current_interval_->start().Value() > position.Value()) { |
| 268 | current_interval_ = NULL; |
| 269 | return first_interval_; |
| 270 | } |
| 271 | return current_interval_; |
| 272 | } |
| 273 | |
| 274 | |
| 275 | void LiveRange::AdvanceLastProcessedMarker( |
| 276 | UseInterval* to_start_of, LifetimePosition but_not_past) const { |
| 277 | if (to_start_of == NULL) return; |
| 278 | if (to_start_of->start().Value() > but_not_past.Value()) return; |
| 279 | LifetimePosition start = |
| 280 | current_interval_ == NULL ? LifetimePosition::Invalid() |
| 281 | : current_interval_->start(); |
| 282 | if (to_start_of->start().Value() > start.Value()) { |
| 283 | current_interval_ = to_start_of; |
| 284 | } |
| 285 | } |
| 286 | |
| 287 | |
| 288 | void LiveRange::SplitAt(LifetimePosition position, LiveRange* result) { |
| 289 | ASSERT(Start().Value() < position.Value()); |
| 290 | ASSERT(result->IsEmpty()); |
| 291 | // Find the last interval that ends before the position. If the |
| 292 | // position is contained in one of the intervals in the chain, we |
| 293 | // split that interval and use the first part. |
| 294 | UseInterval* current = FirstSearchIntervalForPosition(position); |
| 295 | |
| 296 | // If the split position coincides with the beginning of a use interval |
| 297 | // we need to split use positons in a special way. |
| 298 | bool split_at_start = false; |
| 299 | |
| 300 | while (current != NULL) { |
| 301 | if (current->Contains(position)) { |
| 302 | current->SplitAt(position); |
| 303 | break; |
| 304 | } |
| 305 | UseInterval* next = current->next(); |
| 306 | if (next->start().Value() >= position.Value()) { |
| 307 | split_at_start = (next->start().Value() == position.Value()); |
| 308 | break; |
| 309 | } |
| 310 | current = next; |
| 311 | } |
| 312 | |
| 313 | // Partition original use intervals to the two live ranges. |
| 314 | UseInterval* before = current; |
| 315 | UseInterval* after = before->next(); |
| 316 | result->last_interval_ = (last_interval_ == before) |
| 317 | ? after // Only interval in the range after split. |
| 318 | : last_interval_; // Last interval of the original range. |
| 319 | result->first_interval_ = after; |
| 320 | last_interval_ = before; |
| 321 | |
| 322 | // Find the last use position before the split and the first use |
| 323 | // position after it. |
| 324 | UsePosition* use_after = first_pos_; |
| 325 | UsePosition* use_before = NULL; |
| 326 | if (split_at_start) { |
| 327 | // The split position coincides with the beginning of a use interval (the |
| 328 | // end of a lifetime hole). Use at this position should be attributed to |
| 329 | // the split child because split child owns use interval covering it. |
| 330 | while (use_after != NULL && use_after->pos().Value() < position.Value()) { |
| 331 | use_before = use_after; |
| 332 | use_after = use_after->next(); |
| 333 | } |
| 334 | } else { |
| 335 | while (use_after != NULL && use_after->pos().Value() <= position.Value()) { |
| 336 | use_before = use_after; |
| 337 | use_after = use_after->next(); |
| 338 | } |
| 339 | } |
| 340 | |
| 341 | // Partition original use positions to the two live ranges. |
| 342 | if (use_before != NULL) { |
| 343 | use_before->next_ = NULL; |
| 344 | } else { |
| 345 | first_pos_ = NULL; |
| 346 | } |
| 347 | result->first_pos_ = use_after; |
| 348 | |
| 349 | // Link the new live range in the chain before any of the other |
| 350 | // ranges linked from the range before the split. |
| 351 | result->parent_ = (parent_ == NULL) ? this : parent_; |
| 352 | result->next_ = next_; |
| 353 | next_ = result; |
| 354 | |
| 355 | #ifdef DEBUG |
| 356 | Verify(); |
| 357 | result->Verify(); |
| 358 | #endif |
| 359 | } |
| 360 | |
| 361 | |
| 362 | // This implements an ordering on live ranges so that they are ordered by their |
| 363 | // start positions. This is needed for the correctness of the register |
| 364 | // allocation algorithm. If two live ranges start at the same offset then there |
| 365 | // is a tie breaker based on where the value is first used. This part of the |
| 366 | // ordering is merely a heuristic. |
| 367 | bool LiveRange::ShouldBeAllocatedBefore(const LiveRange* other) const { |
| 368 | LifetimePosition start = Start(); |
| 369 | LifetimePosition other_start = other->Start(); |
| 370 | if (start.Value() == other_start.Value()) { |
| 371 | UsePosition* pos = FirstPosWithHint(); |
| 372 | if (pos == NULL) return false; |
| 373 | UsePosition* other_pos = other->first_pos(); |
| 374 | if (other_pos == NULL) return true; |
| 375 | return pos->pos().Value() < other_pos->pos().Value(); |
| 376 | } |
| 377 | return start.Value() < other_start.Value(); |
| 378 | } |
| 379 | |
| 380 | |
| 381 | void LiveRange::ShortenTo(LifetimePosition start) { |
| 382 | LAllocator::TraceAlloc("Shorten live range %d to [%d\n", id_, start.Value()); |
| 383 | ASSERT(first_interval_ != NULL); |
| 384 | ASSERT(first_interval_->start().Value() <= start.Value()); |
| 385 | ASSERT(start.Value() < first_interval_->end().Value()); |
| 386 | first_interval_->set_start(start); |
| 387 | } |
| 388 | |
| 389 | |
| 390 | void LiveRange::EnsureInterval(LifetimePosition start, LifetimePosition end) { |
| 391 | LAllocator::TraceAlloc("Ensure live range %d in interval [%d %d[\n", |
| 392 | id_, |
| 393 | start.Value(), |
| 394 | end.Value()); |
| 395 | LifetimePosition new_end = end; |
| 396 | while (first_interval_ != NULL && |
| 397 | first_interval_->start().Value() <= end.Value()) { |
| 398 | if (first_interval_->end().Value() > end.Value()) { |
| 399 | new_end = first_interval_->end(); |
| 400 | } |
| 401 | first_interval_ = first_interval_->next(); |
| 402 | } |
| 403 | |
| 404 | UseInterval* new_interval = new UseInterval(start, new_end); |
| 405 | new_interval->next_ = first_interval_; |
| 406 | first_interval_ = new_interval; |
| 407 | if (new_interval->next() == NULL) { |
| 408 | last_interval_ = new_interval; |
| 409 | } |
| 410 | } |
| 411 | |
| 412 | |
| 413 | void LiveRange::AddUseInterval(LifetimePosition start, LifetimePosition end) { |
| 414 | LAllocator::TraceAlloc("Add to live range %d interval [%d %d[\n", |
| 415 | id_, |
| 416 | start.Value(), |
| 417 | end.Value()); |
| 418 | if (first_interval_ == NULL) { |
| 419 | UseInterval* interval = new UseInterval(start, end); |
| 420 | first_interval_ = interval; |
| 421 | last_interval_ = interval; |
| 422 | } else { |
| 423 | if (end.Value() == first_interval_->start().Value()) { |
| 424 | first_interval_->set_start(start); |
| 425 | } else if (end.Value() < first_interval_->start().Value()) { |
| 426 | UseInterval* interval = new UseInterval(start, end); |
| 427 | interval->set_next(first_interval_); |
| 428 | first_interval_ = interval; |
| 429 | } else { |
| 430 | // Order of instruction's processing (see ProcessInstructions) guarantees |
| 431 | // that each new use interval either precedes or intersects with |
| 432 | // last added interval. |
| 433 | ASSERT(start.Value() < first_interval_->end().Value()); |
| 434 | first_interval_->start_ = Min(start, first_interval_->start_); |
| 435 | first_interval_->end_ = Max(end, first_interval_->end_); |
| 436 | } |
| 437 | } |
| 438 | } |
| 439 | |
| 440 | |
| 441 | UsePosition* LiveRange::AddUsePosition(LifetimePosition pos, |
| 442 | LOperand* operand) { |
| 443 | LAllocator::TraceAlloc("Add to live range %d use position %d\n", |
| 444 | id_, |
| 445 | pos.Value()); |
| 446 | UsePosition* use_pos = new UsePosition(pos, operand); |
| 447 | UsePosition* prev = NULL; |
| 448 | UsePosition* current = first_pos_; |
| 449 | while (current != NULL && current->pos().Value() < pos.Value()) { |
| 450 | prev = current; |
| 451 | current = current->next(); |
| 452 | } |
| 453 | |
| 454 | if (prev == NULL) { |
| 455 | use_pos->set_next(first_pos_); |
| 456 | first_pos_ = use_pos; |
| 457 | } else { |
| 458 | use_pos->next_ = prev->next_; |
| 459 | prev->next_ = use_pos; |
| 460 | } |
| 461 | |
| 462 | return use_pos; |
| 463 | } |
| 464 | |
| 465 | |
| 466 | void LiveRange::ConvertOperands() { |
| 467 | LOperand* op = CreateAssignedOperand(); |
| 468 | UsePosition* use_pos = first_pos(); |
| 469 | while (use_pos != NULL) { |
| 470 | ASSERT(Start().Value() <= use_pos->pos().Value() && |
| 471 | use_pos->pos().Value() <= End().Value()); |
| 472 | |
| 473 | if (use_pos->HasOperand()) { |
| 474 | ASSERT(op->IsRegister() || op->IsDoubleRegister() || |
| 475 | !use_pos->RequiresRegister()); |
| 476 | use_pos->operand()->ConvertTo(op->kind(), op->index()); |
| 477 | } |
| 478 | use_pos = use_pos->next(); |
| 479 | } |
| 480 | } |
| 481 | |
| 482 | |
| 483 | UsePosition* LiveRange::AddUsePosition(LifetimePosition pos) { |
| 484 | return AddUsePosition(pos, CreateAssignedOperand()); |
| 485 | } |
| 486 | |
| 487 | |
| 488 | bool LiveRange::CanCover(LifetimePosition position) const { |
| 489 | if (IsEmpty()) return false; |
| 490 | return Start().Value() <= position.Value() && |
| 491 | position.Value() < End().Value(); |
| 492 | } |
| 493 | |
| 494 | |
| 495 | bool LiveRange::Covers(LifetimePosition position) { |
| 496 | if (!CanCover(position)) return false; |
| 497 | UseInterval* start_search = FirstSearchIntervalForPosition(position); |
| 498 | for (UseInterval* interval = start_search; |
| 499 | interval != NULL; |
| 500 | interval = interval->next()) { |
| 501 | ASSERT(interval->next() == NULL || |
| 502 | interval->next()->start().Value() >= interval->start().Value()); |
| 503 | AdvanceLastProcessedMarker(interval, position); |
| 504 | if (interval->Contains(position)) return true; |
| 505 | if (interval->start().Value() > position.Value()) return false; |
| 506 | } |
| 507 | return false; |
| 508 | } |
| 509 | |
| 510 | |
| 511 | LifetimePosition LiveRange::FirstIntersection(LiveRange* other) { |
| 512 | UseInterval* b = other->first_interval(); |
| 513 | if (b == NULL) return LifetimePosition::Invalid(); |
| 514 | LifetimePosition advance_last_processed_up_to = b->start(); |
| 515 | UseInterval* a = FirstSearchIntervalForPosition(b->start()); |
| 516 | while (a != NULL && b != NULL) { |
| 517 | if (a->start().Value() > other->End().Value()) break; |
| 518 | if (b->start().Value() > End().Value()) break; |
| 519 | LifetimePosition cur_intersection = a->Intersect(b); |
| 520 | if (cur_intersection.IsValid()) { |
| 521 | return cur_intersection; |
| 522 | } |
| 523 | if (a->start().Value() < b->start().Value()) { |
| 524 | a = a->next(); |
| 525 | if (a == NULL || a->start().Value() > other->End().Value()) break; |
| 526 | AdvanceLastProcessedMarker(a, advance_last_processed_up_to); |
| 527 | } else { |
| 528 | b = b->next(); |
| 529 | } |
| 530 | } |
| 531 | return LifetimePosition::Invalid(); |
| 532 | } |
| 533 | |
| 534 | |
| 535 | void LAllocator::InitializeLivenessAnalysis() { |
| 536 | // Initialize the live_in sets for each block to NULL. |
| 537 | int block_count = graph()->blocks()->length(); |
| 538 | live_in_sets_.Initialize(block_count); |
| 539 | live_in_sets_.AddBlock(NULL, block_count); |
| 540 | } |
| 541 | |
| 542 | |
| 543 | BitVector* LAllocator::ComputeLiveOut(HBasicBlock* block) { |
| 544 | // Compute live out for the given block, except not including backward |
| 545 | // successor edges. |
| 546 | BitVector* live_out = new BitVector(next_virtual_register_); |
| 547 | |
| 548 | // Process all successor blocks. |
| 549 | HBasicBlock* successor = block->end()->FirstSuccessor(); |
| 550 | while (successor != NULL) { |
| 551 | // Add values live on entry to the successor. Note the successor's |
| 552 | // live_in will not be computed yet for backwards edges. |
| 553 | BitVector* live_in = live_in_sets_[successor->block_id()]; |
| 554 | if (live_in != NULL) live_out->Union(*live_in); |
| 555 | |
| 556 | // All phi input operands corresponding to this successor edge are live |
| 557 | // out from this block. |
| 558 | int index = successor->PredecessorIndexOf(block); |
| 559 | const ZoneList<HPhi*>* phis = successor->phis(); |
| 560 | for (int i = 0; i < phis->length(); ++i) { |
| 561 | HPhi* phi = phis->at(i); |
| 562 | if (!phi->OperandAt(index)->IsConstant()) { |
| 563 | live_out->Add(phi->OperandAt(index)->id()); |
| 564 | } |
| 565 | } |
| 566 | |
| 567 | // Check if we are done with second successor. |
| 568 | if (successor == block->end()->SecondSuccessor()) break; |
| 569 | |
| 570 | successor = block->end()->SecondSuccessor(); |
| 571 | } |
| 572 | |
| 573 | return live_out; |
| 574 | } |
| 575 | |
| 576 | |
| 577 | void LAllocator::AddInitialIntervals(HBasicBlock* block, |
| 578 | BitVector* live_out) { |
| 579 | // Add an interval that includes the entire block to the live range for |
| 580 | // each live_out value. |
| 581 | LifetimePosition start = LifetimePosition::FromInstructionIndex( |
| 582 | block->first_instruction_index()); |
| 583 | LifetimePosition end = LifetimePosition::FromInstructionIndex( |
| 584 | block->last_instruction_index()).NextInstruction(); |
| 585 | BitVector::Iterator iterator(live_out); |
| 586 | while (!iterator.Done()) { |
| 587 | int operand_index = iterator.Current(); |
| 588 | LiveRange* range = LiveRangeFor(operand_index); |
| 589 | range->AddUseInterval(start, end); |
| 590 | iterator.Advance(); |
| 591 | } |
| 592 | } |
| 593 | |
| 594 | |
| 595 | int LAllocator::FixedDoubleLiveRangeID(int index) { |
| 596 | return -index - 1 - Register::kNumAllocatableRegisters; |
| 597 | } |
| 598 | |
| 599 | |
| 600 | LOperand* LAllocator::AllocateFixed(LUnallocated* operand, |
| 601 | int pos, |
| 602 | bool is_tagged) { |
| 603 | TraceAlloc("Allocating fixed reg for op %d\n", operand->virtual_register()); |
| 604 | ASSERT(operand->HasFixedPolicy()); |
| 605 | if (operand->policy() == LUnallocated::FIXED_SLOT) { |
| 606 | operand->ConvertTo(LOperand::STACK_SLOT, operand->fixed_index()); |
| 607 | } else if (operand->policy() == LUnallocated::FIXED_REGISTER) { |
| 608 | int reg_index = operand->fixed_index(); |
| 609 | operand->ConvertTo(LOperand::REGISTER, reg_index); |
| 610 | } else if (operand->policy() == LUnallocated::FIXED_DOUBLE_REGISTER) { |
| 611 | int reg_index = operand->fixed_index(); |
| 612 | operand->ConvertTo(LOperand::DOUBLE_REGISTER, reg_index); |
| 613 | } else { |
| 614 | UNREACHABLE(); |
| 615 | } |
| 616 | if (is_tagged) { |
| 617 | TraceAlloc("Fixed reg is tagged at %d\n", pos); |
| 618 | LInstruction* instr = chunk_->instructions()->at(pos); |
| 619 | if (instr->HasPointerMap()) { |
| 620 | instr->pointer_map()->RecordPointer(operand); |
| 621 | } |
| 622 | } |
| 623 | return operand; |
| 624 | } |
| 625 | |
| 626 | |
| 627 | LiveRange* LAllocator::FixedLiveRangeFor(int index) { |
| 628 | if (index >= fixed_live_ranges_.length()) { |
| 629 | fixed_live_ranges_.AddBlock(NULL, |
| 630 | index - fixed_live_ranges_.length() + 1); |
| 631 | } |
| 632 | |
| 633 | LiveRange* result = fixed_live_ranges_[index]; |
| 634 | if (result == NULL) { |
| 635 | result = new LiveRange(FixedLiveRangeID(index)); |
| 636 | ASSERT(result->IsFixed()); |
| 637 | result->set_assigned_register(index, GENERAL_REGISTERS); |
| 638 | fixed_live_ranges_[index] = result; |
| 639 | } |
| 640 | return result; |
| 641 | } |
| 642 | |
| 643 | |
| 644 | LiveRange* LAllocator::FixedDoubleLiveRangeFor(int index) { |
| 645 | if (index >= fixed_double_live_ranges_.length()) { |
| 646 | fixed_double_live_ranges_.AddBlock(NULL, |
| 647 | index - fixed_double_live_ranges_.length() + 1); |
| 648 | } |
| 649 | |
| 650 | LiveRange* result = fixed_double_live_ranges_[index]; |
| 651 | if (result == NULL) { |
| 652 | result = new LiveRange(FixedDoubleLiveRangeID(index)); |
| 653 | ASSERT(result->IsFixed()); |
| 654 | result->set_assigned_register(index, DOUBLE_REGISTERS); |
| 655 | fixed_double_live_ranges_[index] = result; |
| 656 | } |
| 657 | return result; |
| 658 | } |
| 659 | |
| 660 | LiveRange* LAllocator::LiveRangeFor(int index) { |
| 661 | if (index >= live_ranges_.length()) { |
| 662 | live_ranges_.AddBlock(NULL, index - live_ranges_.length() + 1); |
| 663 | } |
| 664 | LiveRange* result = live_ranges_[index]; |
| 665 | if (result == NULL) { |
| 666 | result = new LiveRange(index); |
| 667 | live_ranges_[index] = result; |
| 668 | } |
| 669 | return result; |
| 670 | } |
| 671 | |
| 672 | |
| 673 | LGap* LAllocator::GetLastGap(HBasicBlock* block) const { |
| 674 | int last_instruction = block->last_instruction_index(); |
| 675 | int index = chunk_->NearestGapPos(last_instruction); |
| 676 | return chunk_->GetGapAt(index); |
| 677 | } |
| 678 | |
| 679 | |
| 680 | HPhi* LAllocator::LookupPhi(LOperand* operand) const { |
| 681 | if (!operand->IsUnallocated()) return NULL; |
| 682 | int index = operand->VirtualRegister(); |
| 683 | HValue* instr = graph()->LookupValue(index); |
| 684 | if (instr != NULL && instr->IsPhi()) { |
| 685 | return HPhi::cast(instr); |
| 686 | } |
| 687 | return NULL; |
| 688 | } |
| 689 | |
| 690 | |
| 691 | LiveRange* LAllocator::LiveRangeFor(LOperand* operand) { |
| 692 | if (operand->IsUnallocated()) { |
| 693 | return LiveRangeFor(LUnallocated::cast(operand)->virtual_register()); |
| 694 | } else if (operand->IsRegister()) { |
| 695 | return FixedLiveRangeFor(operand->index()); |
| 696 | } else if (operand->IsDoubleRegister()) { |
| 697 | return FixedDoubleLiveRangeFor(operand->index()); |
| 698 | } else { |
| 699 | return NULL; |
| 700 | } |
| 701 | } |
| 702 | |
| 703 | |
| 704 | void LAllocator::Define(LifetimePosition position, |
| 705 | LOperand* operand, |
| 706 | LOperand* hint) { |
| 707 | LiveRange* range = LiveRangeFor(operand); |
| 708 | if (range == NULL) return; |
| 709 | |
| 710 | if (range->IsEmpty() || range->Start().Value() > position.Value()) { |
| 711 | // Can happen if there is a definition without use. |
| 712 | range->AddUseInterval(position, position.NextInstruction()); |
| 713 | range->AddUsePosition(position.NextInstruction(), NULL); |
| 714 | } else { |
| 715 | range->ShortenTo(position); |
| 716 | } |
| 717 | |
| 718 | if (operand->IsUnallocated()) { |
| 719 | LUnallocated* unalloc_operand = LUnallocated::cast(operand); |
| 720 | range->AddUsePosition(position, unalloc_operand)->set_hint(hint); |
| 721 | } |
| 722 | } |
| 723 | |
| 724 | |
| 725 | void LAllocator::Use(LifetimePosition block_start, |
| 726 | LifetimePosition position, |
| 727 | LOperand* operand, |
| 728 | LOperand* hint) { |
| 729 | LiveRange* range = LiveRangeFor(operand); |
| 730 | if (range == NULL) return; |
| 731 | if (operand->IsUnallocated()) { |
| 732 | LUnallocated* unalloc_operand = LUnallocated::cast(operand); |
| 733 | range->AddUsePosition(position, unalloc_operand)->set_hint(hint); |
| 734 | } |
| 735 | range->AddUseInterval(block_start, position); |
| 736 | } |
| 737 | |
| 738 | |
| 739 | void LAllocator::AddConstraintsGapMove(int index, |
| 740 | LOperand* from, |
| 741 | LOperand* to) { |
| 742 | LGap* gap = chunk_->GetGapAt(index); |
| 743 | LParallelMove* move = gap->GetOrCreateParallelMove(LGap::START); |
| 744 | if (from->IsUnallocated()) { |
| 745 | const ZoneList<LMoveOperands>* move_operands = move->move_operands(); |
| 746 | for (int i = 0; i < move_operands->length(); ++i) { |
| 747 | LMoveOperands cur = move_operands->at(i); |
| 748 | LOperand* cur_to = cur.to(); |
| 749 | if (cur_to->IsUnallocated()) { |
| 750 | if (cur_to->VirtualRegister() == from->VirtualRegister()) { |
| 751 | move->AddMove(cur.from(), to); |
| 752 | return; |
| 753 | } |
| 754 | } |
| 755 | } |
| 756 | } |
| 757 | move->AddMove(from, to); |
| 758 | } |
| 759 | |
| 760 | |
| 761 | void LAllocator::MeetRegisterConstraints(HBasicBlock* block) { |
| 762 | int start = block->first_instruction_index(); |
| 763 | int end = block->last_instruction_index(); |
| 764 | for (int i = start; i <= end; ++i) { |
| 765 | if (chunk_->IsGapAt(i)) { |
| 766 | InstructionSummary* summary = NULL; |
| 767 | InstructionSummary* prev_summary = NULL; |
| 768 | if (i < end) summary = GetSummary(i + 1); |
| 769 | if (i > start) prev_summary = GetSummary(i - 1); |
| 770 | MeetConstraintsBetween(prev_summary, summary, i); |
| 771 | } |
| 772 | } |
| 773 | } |
| 774 | |
| 775 | |
| 776 | void LAllocator::MeetConstraintsBetween(InstructionSummary* first, |
| 777 | InstructionSummary* second, |
| 778 | int gap_index) { |
| 779 | // Handle fixed temporaries. |
| 780 | if (first != NULL) { |
| 781 | for (int i = 0; i < first->TempCount(); ++i) { |
| 782 | LUnallocated* temp = LUnallocated::cast(first->TempAt(i)); |
| 783 | if (temp->HasFixedPolicy()) { |
| 784 | AllocateFixed(temp, gap_index - 1, false); |
| 785 | } |
| 786 | } |
| 787 | } |
| 788 | |
| 789 | // Handle fixed output operand. |
| 790 | if (first != NULL && first->Output() != NULL) { |
| 791 | LUnallocated* first_output = LUnallocated::cast(first->Output()); |
| 792 | LiveRange* range = LiveRangeFor(first_output->VirtualRegister()); |
| 793 | bool assigned = false; |
| 794 | if (first_output->HasFixedPolicy()) { |
| 795 | LUnallocated* output_copy = first_output->CopyUnconstrained(); |
| 796 | bool is_tagged = HasTaggedValue(first_output->VirtualRegister()); |
| 797 | AllocateFixed(first_output, gap_index, is_tagged); |
| 798 | |
| 799 | // This value is produced on the stack, we never need to spill it. |
| 800 | if (first_output->IsStackSlot()) { |
| 801 | range->SetSpillOperand(first_output); |
| 802 | range->SetSpillStartIndex(gap_index - 1); |
| 803 | assigned = true; |
| 804 | } |
| 805 | chunk_->AddGapMove(gap_index, first_output, output_copy); |
| 806 | } |
| 807 | |
| 808 | if (!assigned) { |
| 809 | range->SetSpillStartIndex(gap_index); |
| 810 | |
| 811 | // This move to spill operand is not a real use. Liveness analysis |
| 812 | // and splitting of live ranges do not account for it. |
| 813 | // Thus it should be inserted to a lifetime position corresponding to |
| 814 | // the instruction end. |
| 815 | LGap* gap = chunk_->GetGapAt(gap_index); |
| 816 | LParallelMove* move = gap->GetOrCreateParallelMove(LGap::BEFORE); |
| 817 | move->AddMove(first_output, range->GetSpillOperand()); |
| 818 | } |
| 819 | } |
| 820 | |
| 821 | // Handle fixed input operands of second instruction. |
| 822 | if (second != NULL) { |
| 823 | for (int i = 0; i < second->InputCount(); ++i) { |
| 824 | LUnallocated* cur_input = LUnallocated::cast(second->InputAt(i)); |
| 825 | if (cur_input->HasFixedPolicy()) { |
| 826 | LUnallocated* input_copy = cur_input->CopyUnconstrained(); |
| 827 | bool is_tagged = HasTaggedValue(cur_input->VirtualRegister()); |
| 828 | AllocateFixed(cur_input, gap_index + 1, is_tagged); |
| 829 | AddConstraintsGapMove(gap_index, input_copy, cur_input); |
| 830 | } else if (cur_input->policy() == LUnallocated::WRITABLE_REGISTER) { |
| 831 | LUnallocated* input_copy = cur_input->CopyUnconstrained(); |
| 832 | cur_input->set_virtual_register(next_virtual_register_++); |
Steve Block | 9fac840 | 2011-05-12 15:51:54 +0100 | [diff] [blame^] | 833 | |
| 834 | if (RequiredRegisterKind(input_copy->virtual_register()) == |
| 835 | DOUBLE_REGISTERS) { |
| 836 | double_artificial_registers_.Add( |
| 837 | cur_input->virtual_register() - first_artificial_register_); |
| 838 | } |
| 839 | |
Ben Murdoch | b0fe162 | 2011-05-05 13:52:32 +0100 | [diff] [blame] | 840 | second->AddTemp(cur_input); |
| 841 | AddConstraintsGapMove(gap_index, input_copy, cur_input); |
| 842 | } |
| 843 | } |
| 844 | } |
| 845 | |
| 846 | // Handle "output same as input" for second instruction. |
| 847 | if (second != NULL && second->Output() != NULL) { |
| 848 | LUnallocated* second_output = LUnallocated::cast(second->Output()); |
| 849 | if (second_output->HasSameAsInputPolicy()) { |
| 850 | LUnallocated* cur_input = LUnallocated::cast(second->InputAt(0)); |
| 851 | int output_vreg = second_output->VirtualRegister(); |
| 852 | int input_vreg = cur_input->VirtualRegister(); |
| 853 | |
| 854 | LUnallocated* input_copy = cur_input->CopyUnconstrained(); |
| 855 | cur_input->set_virtual_register(second_output->virtual_register()); |
| 856 | AddConstraintsGapMove(gap_index, input_copy, cur_input); |
| 857 | |
| 858 | if (HasTaggedValue(input_vreg) && !HasTaggedValue(output_vreg)) { |
| 859 | int index = gap_index + 1; |
| 860 | LInstruction* instr = chunk_->instructions()->at(index); |
| 861 | if (instr->HasPointerMap()) { |
| 862 | instr->pointer_map()->RecordPointer(input_copy); |
| 863 | } |
| 864 | } else if (!HasTaggedValue(input_vreg) && HasTaggedValue(output_vreg)) { |
| 865 | // The input is assumed to immediately have a tagged representation, |
| 866 | // before the pointer map can be used. I.e. the pointer map at the |
| 867 | // instruction will include the output operand (whose value at the |
| 868 | // beginning of the instruction is equal to the input operand). If |
| 869 | // this is not desired, then the pointer map at this instruction needs |
| 870 | // to be adjusted manually. |
| 871 | } |
| 872 | } |
| 873 | } |
| 874 | } |
| 875 | |
| 876 | |
| 877 | void LAllocator::ProcessInstructions(HBasicBlock* block, BitVector* live) { |
| 878 | int block_start = block->first_instruction_index(); |
| 879 | int index = block->last_instruction_index(); |
| 880 | |
| 881 | LifetimePosition block_start_position = |
| 882 | LifetimePosition::FromInstructionIndex(block_start); |
| 883 | |
| 884 | while (index >= block_start) { |
| 885 | LifetimePosition curr_position = |
| 886 | LifetimePosition::FromInstructionIndex(index); |
| 887 | |
| 888 | if (chunk_->IsGapAt(index)) { |
| 889 | // We have a gap at this position. |
| 890 | LGap* gap = chunk_->GetGapAt(index); |
| 891 | LParallelMove* move = gap->GetOrCreateParallelMove(LGap::START); |
| 892 | const ZoneList<LMoveOperands>* move_operands = move->move_operands(); |
| 893 | for (int i = 0; i < move_operands->length(); ++i) { |
| 894 | LMoveOperands* cur = &move_operands->at(i); |
| 895 | if (cur->IsIgnored()) continue; |
| 896 | LOperand* from = cur->from(); |
| 897 | LOperand* to = cur->to(); |
| 898 | HPhi* phi = LookupPhi(to); |
| 899 | LOperand* hint = to; |
| 900 | if (phi != NULL) { |
| 901 | // This is a phi resolving move. |
| 902 | if (!phi->block()->IsLoopHeader()) { |
| 903 | hint = LiveRangeFor(phi->id())->FirstHint(); |
| 904 | } |
| 905 | } else { |
| 906 | if (to->IsUnallocated()) { |
| 907 | if (live->Contains(to->VirtualRegister())) { |
| 908 | Define(curr_position, to, from); |
| 909 | live->Remove(to->VirtualRegister()); |
| 910 | } else { |
| 911 | cur->Eliminate(); |
| 912 | continue; |
| 913 | } |
| 914 | } else { |
| 915 | Define(curr_position, to, from); |
| 916 | } |
| 917 | } |
| 918 | Use(block_start_position, curr_position, from, hint); |
| 919 | if (from->IsUnallocated()) { |
| 920 | live->Add(from->VirtualRegister()); |
| 921 | } |
| 922 | } |
| 923 | } else { |
| 924 | ASSERT(!chunk_->IsGapAt(index)); |
| 925 | InstructionSummary* summary = GetSummary(index); |
| 926 | |
| 927 | if (summary != NULL) { |
| 928 | LOperand* output = summary->Output(); |
| 929 | if (output != NULL) { |
| 930 | if (output->IsUnallocated()) live->Remove(output->VirtualRegister()); |
| 931 | Define(curr_position, output, NULL); |
| 932 | } |
| 933 | |
| 934 | if (summary->IsCall()) { |
| 935 | for (int i = 0; i < Register::kNumAllocatableRegisters; ++i) { |
| 936 | if (output == NULL || !output->IsRegister() || |
| 937 | output->index() != i) { |
| 938 | LiveRange* range = FixedLiveRangeFor(i); |
| 939 | range->AddUseInterval(curr_position, |
| 940 | curr_position.InstructionEnd()); |
| 941 | } |
| 942 | } |
| 943 | for (int i = 0; i < DoubleRegister::kNumAllocatableRegisters; ++i) { |
| 944 | if (output == NULL || !output->IsDoubleRegister() || |
| 945 | output->index() != i) { |
| 946 | LiveRange* range = FixedDoubleLiveRangeFor(i); |
| 947 | range->AddUseInterval(curr_position, |
| 948 | curr_position.InstructionEnd()); |
| 949 | } |
| 950 | } |
| 951 | } |
| 952 | |
| 953 | for (int i = 0; i < summary->InputCount(); ++i) { |
| 954 | LOperand* input = summary->InputAt(i); |
| 955 | |
| 956 | LifetimePosition use_pos; |
| 957 | if (input->IsUnallocated() && |
| 958 | LUnallocated::cast(input)->IsUsedAtStart()) { |
| 959 | use_pos = curr_position; |
| 960 | } else { |
| 961 | use_pos = curr_position.InstructionEnd(); |
| 962 | } |
| 963 | |
| 964 | Use(block_start_position, use_pos, input, NULL); |
| 965 | if (input->IsUnallocated()) live->Add(input->VirtualRegister()); |
| 966 | } |
| 967 | |
| 968 | for (int i = 0; i < summary->TempCount(); ++i) { |
| 969 | LOperand* temp = summary->TempAt(i); |
| 970 | if (summary->IsCall()) { |
| 971 | if (temp->IsRegister()) continue; |
| 972 | if (temp->IsUnallocated()) { |
| 973 | LUnallocated* temp_unalloc = LUnallocated::cast(temp); |
| 974 | if (temp_unalloc->HasFixedPolicy()) { |
| 975 | continue; |
| 976 | } |
| 977 | } |
| 978 | } |
| 979 | Use(block_start_position, curr_position.InstructionEnd(), temp, NULL); |
| 980 | Define(curr_position, temp, NULL); |
| 981 | } |
| 982 | } |
| 983 | } |
| 984 | |
| 985 | index = index - 1; |
| 986 | } |
| 987 | } |
| 988 | |
| 989 | |
| 990 | void LAllocator::ResolvePhis(HBasicBlock* block) { |
| 991 | const ZoneList<HPhi*>* phis = block->phis(); |
| 992 | for (int i = 0; i < phis->length(); ++i) { |
| 993 | HPhi* phi = phis->at(i); |
| 994 | LUnallocated* phi_operand = new LUnallocated(LUnallocated::NONE); |
| 995 | phi_operand->set_virtual_register(phi->id()); |
| 996 | for (int j = 0; j < phi->OperandCount(); ++j) { |
| 997 | HValue* op = phi->OperandAt(j); |
| 998 | LOperand* operand = NULL; |
| 999 | if (op->IsConstant() && op->EmitAtUses()) { |
| 1000 | HConstant* constant = HConstant::cast(op); |
| 1001 | operand = chunk_->DefineConstantOperand(constant); |
| 1002 | } else { |
| 1003 | ASSERT(!op->EmitAtUses()); |
| 1004 | LUnallocated* unalloc = new LUnallocated(LUnallocated::NONE); |
| 1005 | unalloc->set_virtual_register(op->id()); |
| 1006 | operand = unalloc; |
| 1007 | } |
| 1008 | HBasicBlock* cur_block = block->predecessors()->at(j); |
| 1009 | // The gap move must be added without any special processing as in |
| 1010 | // the AddConstraintsGapMove. |
| 1011 | chunk_->AddGapMove(cur_block->last_instruction_index() - 1, |
| 1012 | operand, |
| 1013 | phi_operand); |
| 1014 | } |
| 1015 | |
| 1016 | LiveRange* live_range = LiveRangeFor(phi->id()); |
| 1017 | LLabel* label = chunk_->GetLabel(phi->block()->block_id()); |
| 1018 | label->GetOrCreateParallelMove(LGap::START)-> |
| 1019 | AddMove(phi_operand, live_range->GetSpillOperand()); |
| 1020 | live_range->SetSpillStartIndex(phi->block()->first_instruction_index()); |
| 1021 | } |
| 1022 | } |
| 1023 | |
| 1024 | |
| 1025 | void LAllocator::Allocate(LChunk* chunk) { |
| 1026 | ASSERT(chunk_ == NULL); |
| 1027 | chunk_ = chunk; |
| 1028 | MeetRegisterConstraints(); |
| 1029 | ResolvePhis(); |
| 1030 | BuildLiveRanges(); |
| 1031 | AllocateGeneralRegisters(); |
| 1032 | AllocateDoubleRegisters(); |
| 1033 | PopulatePointerMaps(); |
| 1034 | if (has_osr_entry_) ProcessOsrEntry(); |
| 1035 | ConnectRanges(); |
| 1036 | ResolveControlFlow(); |
| 1037 | } |
| 1038 | |
| 1039 | |
| 1040 | void LAllocator::MeetRegisterConstraints() { |
| 1041 | HPhase phase("Register constraints", chunk()); |
Steve Block | 9fac840 | 2011-05-12 15:51:54 +0100 | [diff] [blame^] | 1042 | first_artificial_register_ = next_virtual_register_; |
Ben Murdoch | b0fe162 | 2011-05-05 13:52:32 +0100 | [diff] [blame] | 1043 | const ZoneList<HBasicBlock*>* blocks = graph()->blocks(); |
| 1044 | for (int i = 0; i < blocks->length(); ++i) { |
| 1045 | HBasicBlock* block = blocks->at(i); |
| 1046 | MeetRegisterConstraints(block); |
| 1047 | } |
| 1048 | } |
| 1049 | |
| 1050 | |
| 1051 | void LAllocator::ResolvePhis() { |
| 1052 | HPhase phase("Resolve phis", chunk()); |
| 1053 | |
| 1054 | // Process the blocks in reverse order. |
| 1055 | const ZoneList<HBasicBlock*>* blocks = graph()->blocks(); |
| 1056 | for (int block_id = blocks->length() - 1; block_id >= 0; --block_id) { |
| 1057 | HBasicBlock* block = blocks->at(block_id); |
| 1058 | ResolvePhis(block); |
| 1059 | } |
| 1060 | } |
| 1061 | |
| 1062 | |
| 1063 | void LAllocator::ResolveControlFlow(LiveRange* range, |
| 1064 | HBasicBlock* block, |
| 1065 | HBasicBlock* pred) { |
| 1066 | LifetimePosition pred_end = |
| 1067 | LifetimePosition::FromInstructionIndex(pred->last_instruction_index()). |
| 1068 | PrevInstruction(); |
| 1069 | |
| 1070 | LifetimePosition cur_start = |
| 1071 | LifetimePosition::FromInstructionIndex(block->first_instruction_index()); |
| 1072 | LiveRange* pred_cover = NULL; |
| 1073 | LiveRange* cur_cover = NULL; |
| 1074 | LiveRange* cur_range = range; |
| 1075 | while (cur_range != NULL && (cur_cover == NULL || pred_cover == NULL)) { |
| 1076 | if (cur_range->CanCover(cur_start)) { |
| 1077 | ASSERT(cur_cover == NULL); |
| 1078 | cur_cover = cur_range; |
| 1079 | } |
| 1080 | if (cur_range->CanCover(pred_end)) { |
| 1081 | ASSERT(pred_cover == NULL); |
| 1082 | pred_cover = cur_range; |
| 1083 | } |
| 1084 | cur_range = cur_range->next(); |
| 1085 | } |
| 1086 | |
| 1087 | if (cur_cover->IsSpilled()) return; |
| 1088 | ASSERT(pred_cover != NULL && cur_cover != NULL); |
| 1089 | if (pred_cover != cur_cover) { |
| 1090 | LOperand* pred_op = pred_cover->CreateAssignedOperand(); |
| 1091 | LOperand* cur_op = cur_cover->CreateAssignedOperand(); |
| 1092 | if (!pred_op->Equals(cur_op)) { |
| 1093 | LGap* gap = NULL; |
| 1094 | if (block->predecessors()->length() == 1) { |
| 1095 | gap = chunk_->GetGapAt(block->first_instruction_index()); |
| 1096 | } else { |
| 1097 | ASSERT(pred->end()->SecondSuccessor() == NULL); |
| 1098 | gap = GetLastGap(pred); |
| 1099 | } |
| 1100 | gap->GetOrCreateParallelMove(LGap::START)->AddMove(pred_op, cur_op); |
| 1101 | } |
| 1102 | } |
| 1103 | } |
| 1104 | |
| 1105 | |
| 1106 | LParallelMove* LAllocator::GetConnectingParallelMove(LifetimePosition pos) { |
| 1107 | int index = pos.InstructionIndex(); |
| 1108 | if (chunk_->IsGapAt(index)) { |
| 1109 | LGap* gap = chunk_->GetGapAt(index); |
| 1110 | return gap->GetOrCreateParallelMove( |
| 1111 | pos.IsInstructionStart() ? LGap::START : LGap::END); |
| 1112 | } |
| 1113 | int gap_pos = pos.IsInstructionStart() ? (index - 1) : (index + 1); |
| 1114 | return chunk_->GetGapAt(gap_pos)->GetOrCreateParallelMove( |
| 1115 | (gap_pos < index) ? LGap::AFTER : LGap::BEFORE); |
| 1116 | } |
| 1117 | |
| 1118 | |
| 1119 | HBasicBlock* LAllocator::GetBlock(LifetimePosition pos) { |
| 1120 | LGap* gap = chunk_->GetGapAt(chunk_->NearestGapPos(pos.InstructionIndex())); |
| 1121 | return gap->block(); |
| 1122 | } |
| 1123 | |
| 1124 | |
| 1125 | void LAllocator::ConnectRanges() { |
| 1126 | HPhase phase("Connect ranges", this); |
| 1127 | for (int i = 0; i < live_ranges()->length(); ++i) { |
| 1128 | LiveRange* first_range = live_ranges()->at(i); |
| 1129 | if (first_range == NULL || first_range->parent() != NULL) continue; |
| 1130 | |
| 1131 | LiveRange* second_range = first_range->next(); |
| 1132 | while (second_range != NULL) { |
| 1133 | LifetimePosition pos = second_range->Start(); |
| 1134 | |
| 1135 | if (!second_range->IsSpilled()) { |
| 1136 | // Add gap move if the two live ranges touch and there is no block |
| 1137 | // boundary. |
| 1138 | if (first_range->End().Value() == pos.Value()) { |
| 1139 | bool should_insert = true; |
| 1140 | if (IsBlockBoundary(pos)) { |
| 1141 | should_insert = CanEagerlyResolveControlFlow(GetBlock(pos)); |
| 1142 | } |
| 1143 | if (should_insert) { |
| 1144 | LParallelMove* move = GetConnectingParallelMove(pos); |
| 1145 | LOperand* prev_operand = first_range->CreateAssignedOperand(); |
| 1146 | LOperand* cur_operand = second_range->CreateAssignedOperand(); |
| 1147 | move->AddMove(prev_operand, cur_operand); |
| 1148 | } |
| 1149 | } |
| 1150 | } |
| 1151 | |
| 1152 | first_range = second_range; |
| 1153 | second_range = second_range->next(); |
| 1154 | } |
| 1155 | } |
| 1156 | } |
| 1157 | |
| 1158 | |
| 1159 | bool LAllocator::CanEagerlyResolveControlFlow(HBasicBlock* block) const { |
| 1160 | if (block->predecessors()->length() != 1) return false; |
| 1161 | return block->predecessors()->first()->block_id() == block->block_id() - 1; |
| 1162 | } |
| 1163 | |
| 1164 | |
| 1165 | void LAllocator::ResolveControlFlow() { |
| 1166 | HPhase phase("Resolve control flow", this); |
| 1167 | const ZoneList<HBasicBlock*>* blocks = graph()->blocks(); |
| 1168 | for (int block_id = 1; block_id < blocks->length(); ++block_id) { |
| 1169 | HBasicBlock* block = blocks->at(block_id); |
| 1170 | if (CanEagerlyResolveControlFlow(block)) continue; |
| 1171 | BitVector* live = live_in_sets_[block->block_id()]; |
| 1172 | BitVector::Iterator iterator(live); |
| 1173 | while (!iterator.Done()) { |
| 1174 | int operand_index = iterator.Current(); |
| 1175 | for (int i = 0; i < block->predecessors()->length(); ++i) { |
| 1176 | HBasicBlock* cur = block->predecessors()->at(i); |
| 1177 | LiveRange* cur_range = LiveRangeFor(operand_index); |
| 1178 | ResolveControlFlow(cur_range, block, cur); |
| 1179 | } |
| 1180 | iterator.Advance(); |
| 1181 | } |
| 1182 | } |
| 1183 | } |
| 1184 | |
| 1185 | |
| 1186 | void LAllocator::BuildLiveRanges() { |
| 1187 | HPhase phase("Build live ranges", this); |
| 1188 | InitializeLivenessAnalysis(); |
| 1189 | // Process the blocks in reverse order. |
| 1190 | const ZoneList<HBasicBlock*>* blocks = graph()->blocks(); |
| 1191 | for (int block_id = blocks->length() - 1; block_id >= 0; --block_id) { |
| 1192 | HBasicBlock* block = blocks->at(block_id); |
| 1193 | BitVector* live = ComputeLiveOut(block); |
| 1194 | // Initially consider all live_out values live for the entire block. We |
| 1195 | // will shorten these intervals if necessary. |
| 1196 | AddInitialIntervals(block, live); |
| 1197 | |
| 1198 | // Process the instructions in reverse order, generating and killing |
| 1199 | // live values. |
| 1200 | ProcessInstructions(block, live); |
| 1201 | // All phi output operands are killed by this block. |
| 1202 | const ZoneList<HPhi*>* phis = block->phis(); |
| 1203 | for (int i = 0; i < phis->length(); ++i) { |
| 1204 | // The live range interval already ends at the first instruction of the |
| 1205 | // block. |
| 1206 | HPhi* phi = phis->at(i); |
| 1207 | live->Remove(phi->id()); |
| 1208 | |
| 1209 | LOperand* hint = NULL; |
| 1210 | LOperand* phi_operand = NULL; |
| 1211 | LGap* gap = GetLastGap(phi->block()->predecessors()->at(0)); |
| 1212 | LParallelMove* move = gap->GetOrCreateParallelMove(LGap::START); |
| 1213 | for (int j = 0; j < move->move_operands()->length(); ++j) { |
| 1214 | LOperand* to = move->move_operands()->at(j).to(); |
| 1215 | if (to->IsUnallocated() && to->VirtualRegister() == phi->id()) { |
| 1216 | hint = move->move_operands()->at(j).from(); |
| 1217 | phi_operand = to; |
| 1218 | break; |
| 1219 | } |
| 1220 | } |
| 1221 | ASSERT(hint != NULL); |
| 1222 | |
| 1223 | LifetimePosition block_start = LifetimePosition::FromInstructionIndex( |
| 1224 | block->first_instruction_index()); |
| 1225 | Define(block_start, phi_operand, hint); |
| 1226 | } |
| 1227 | |
| 1228 | // Now live is live_in for this block except not including values live |
| 1229 | // out on backward successor edges. |
| 1230 | live_in_sets_[block_id] = live; |
| 1231 | |
| 1232 | // If this block is a loop header go back and patch up the necessary |
| 1233 | // predecessor blocks. |
| 1234 | if (block->IsLoopHeader()) { |
| 1235 | // TODO(kmillikin): Need to be able to get the last block of the loop |
| 1236 | // in the loop information. Add a live range stretching from the first |
| 1237 | // loop instruction to the last for each value live on entry to the |
| 1238 | // header. |
| 1239 | HBasicBlock* back_edge = block->loop_information()->GetLastBackEdge(); |
| 1240 | BitVector::Iterator iterator(live); |
| 1241 | LifetimePosition start = LifetimePosition::FromInstructionIndex( |
| 1242 | block->first_instruction_index()); |
| 1243 | LifetimePosition end = LifetimePosition::FromInstructionIndex( |
| 1244 | back_edge->last_instruction_index()); |
| 1245 | while (!iterator.Done()) { |
| 1246 | int operand_index = iterator.Current(); |
| 1247 | LiveRange* range = LiveRangeFor(operand_index); |
| 1248 | range->EnsureInterval(start, end); |
| 1249 | iterator.Advance(); |
| 1250 | } |
| 1251 | |
| 1252 | for (int i = block->block_id() + 1; i <= back_edge->block_id(); ++i) { |
| 1253 | live_in_sets_[i]->Union(*live); |
| 1254 | } |
| 1255 | } |
| 1256 | |
| 1257 | #ifdef DEBUG |
| 1258 | if (block_id == 0) { |
| 1259 | BitVector::Iterator iterator(live); |
| 1260 | bool found = false; |
| 1261 | while (!iterator.Done()) { |
| 1262 | found = true; |
| 1263 | int operand_index = iterator.Current(); |
| 1264 | PrintF("Function: %s\n", |
| 1265 | *graph()->info()->function()->debug_name()->ToCString()); |
| 1266 | PrintF("Value %d used before first definition!\n", operand_index); |
| 1267 | LiveRange* range = LiveRangeFor(operand_index); |
| 1268 | PrintF("First use is at %d\n", range->first_pos()->pos().Value()); |
| 1269 | iterator.Advance(); |
| 1270 | } |
| 1271 | ASSERT(!found); |
| 1272 | } |
| 1273 | #endif |
| 1274 | } |
| 1275 | } |
| 1276 | |
| 1277 | |
| 1278 | bool LAllocator::SafePointsAreInOrder() const { |
| 1279 | const ZoneList<LPointerMap*>* pointer_maps = chunk_->pointer_maps(); |
| 1280 | int safe_point = 0; |
| 1281 | for (int i = 0; i < pointer_maps->length(); ++i) { |
| 1282 | LPointerMap* map = pointer_maps->at(i); |
| 1283 | if (safe_point > map->lithium_position()) return false; |
| 1284 | safe_point = map->lithium_position(); |
| 1285 | } |
| 1286 | return true; |
| 1287 | } |
| 1288 | |
| 1289 | |
| 1290 | void LAllocator::PopulatePointerMaps() { |
| 1291 | HPhase phase("Populate pointer maps", this); |
| 1292 | const ZoneList<LPointerMap*>* pointer_maps = chunk_->pointer_maps(); |
| 1293 | |
| 1294 | ASSERT(SafePointsAreInOrder()); |
| 1295 | |
| 1296 | // Iterate over all safe point positions and record a pointer |
| 1297 | // for all spilled live ranges at this point. |
| 1298 | int first_safe_point_index = 0; |
| 1299 | int last_range_start = 0; |
| 1300 | for (int range_idx = 0; range_idx < live_ranges()->length(); ++range_idx) { |
| 1301 | LiveRange* range = live_ranges()->at(range_idx); |
| 1302 | if (range == NULL) continue; |
| 1303 | // Iterate over the first parts of multi-part live ranges. |
| 1304 | if (range->parent() != NULL) continue; |
| 1305 | // Skip non-pointer values. |
| 1306 | if (!HasTaggedValue(range->id())) continue; |
| 1307 | // Skip empty live ranges. |
| 1308 | if (range->IsEmpty()) continue; |
| 1309 | |
| 1310 | // Find the extent of the range and its children. |
| 1311 | int start = range->Start().InstructionIndex(); |
| 1312 | int end = 0; |
| 1313 | for (LiveRange* cur = range; cur != NULL; cur = cur->next()) { |
| 1314 | LifetimePosition this_end = cur->End(); |
| 1315 | if (this_end.InstructionIndex() > end) end = this_end.InstructionIndex(); |
| 1316 | ASSERT(cur->Start().InstructionIndex() >= start); |
| 1317 | } |
| 1318 | |
| 1319 | // Most of the ranges are in order, but not all. Keep an eye on when |
| 1320 | // they step backwards and reset the first_safe_point_index so we don't |
| 1321 | // miss any safe points. |
| 1322 | if (start < last_range_start) { |
| 1323 | first_safe_point_index = 0; |
| 1324 | } |
| 1325 | last_range_start = start; |
| 1326 | |
| 1327 | // Step across all the safe points that are before the start of this range, |
| 1328 | // recording how far we step in order to save doing this for the next range. |
| 1329 | while (first_safe_point_index < pointer_maps->length()) { |
| 1330 | LPointerMap* map = pointer_maps->at(first_safe_point_index); |
| 1331 | int safe_point = map->lithium_position(); |
| 1332 | if (safe_point >= start) break; |
| 1333 | first_safe_point_index++; |
| 1334 | } |
| 1335 | |
| 1336 | // Step through the safe points to see whether they are in the range. |
| 1337 | for (int safe_point_index = first_safe_point_index; |
| 1338 | safe_point_index < pointer_maps->length(); |
| 1339 | ++safe_point_index) { |
| 1340 | LPointerMap* map = pointer_maps->at(safe_point_index); |
| 1341 | int safe_point = map->lithium_position(); |
| 1342 | |
| 1343 | // The safe points are sorted so we can stop searching here. |
| 1344 | if (safe_point - 1 > end) break; |
| 1345 | |
| 1346 | // Advance to the next active range that covers the current |
| 1347 | // safe point position. |
| 1348 | LifetimePosition safe_point_pos = |
| 1349 | LifetimePosition::FromInstructionIndex(safe_point); |
| 1350 | LiveRange* cur = range; |
| 1351 | while (cur != NULL && !cur->Covers(safe_point_pos.PrevInstruction())) { |
| 1352 | cur = cur->next(); |
| 1353 | } |
| 1354 | if (cur == NULL) continue; |
| 1355 | |
| 1356 | // Check if the live range is spilled and the safe point is after |
| 1357 | // the spill position. |
| 1358 | if (range->HasAllocatedSpillOperand() && |
| 1359 | safe_point >= range->spill_start_index()) { |
| 1360 | TraceAlloc("Pointer for range %d (spilled at %d) at safe point %d\n", |
| 1361 | range->id(), range->spill_start_index(), safe_point); |
| 1362 | map->RecordPointer(range->GetSpillOperand()); |
| 1363 | } |
| 1364 | |
| 1365 | if (!cur->IsSpilled()) { |
| 1366 | TraceAlloc("Pointer in register for range %d (start at %d) " |
| 1367 | "at safe point %d\n", |
| 1368 | cur->id(), cur->Start().Value(), safe_point); |
| 1369 | LOperand* operand = cur->CreateAssignedOperand(); |
| 1370 | ASSERT(!operand->IsStackSlot()); |
| 1371 | map->RecordPointer(operand); |
| 1372 | } |
| 1373 | } |
| 1374 | } |
| 1375 | } |
| 1376 | |
| 1377 | |
| 1378 | void LAllocator::ProcessOsrEntry() { |
| 1379 | const ZoneList<LInstruction*>* instrs = chunk_->instructions(); |
| 1380 | |
| 1381 | // Linear search for the OSR entry instruction in the chunk. |
| 1382 | int index = -1; |
| 1383 | while (++index < instrs->length() && |
| 1384 | !instrs->at(index)->IsOsrEntry()) { |
| 1385 | } |
| 1386 | ASSERT(index < instrs->length()); |
| 1387 | LOsrEntry* instruction = LOsrEntry::cast(instrs->at(index)); |
| 1388 | |
| 1389 | LifetimePosition position = LifetimePosition::FromInstructionIndex(index); |
| 1390 | for (int i = 0; i < live_ranges()->length(); ++i) { |
| 1391 | LiveRange* range = live_ranges()->at(i); |
| 1392 | if (range != NULL) { |
| 1393 | if (range->Covers(position) && |
| 1394 | range->HasRegisterAssigned() && |
| 1395 | range->TopLevel()->HasAllocatedSpillOperand()) { |
| 1396 | int reg_index = range->assigned_register(); |
| 1397 | LOperand* spill_operand = range->TopLevel()->GetSpillOperand(); |
| 1398 | if (range->IsDouble()) { |
| 1399 | instruction->MarkSpilledDoubleRegister(reg_index, spill_operand); |
| 1400 | } else { |
| 1401 | instruction->MarkSpilledRegister(reg_index, spill_operand); |
| 1402 | } |
| 1403 | } |
| 1404 | } |
| 1405 | } |
| 1406 | } |
| 1407 | |
| 1408 | |
| 1409 | void LAllocator::AllocateGeneralRegisters() { |
| 1410 | HPhase phase("Allocate general registers", this); |
| 1411 | num_registers_ = Register::kNumAllocatableRegisters; |
| 1412 | mode_ = GENERAL_REGISTERS; |
| 1413 | AllocateRegisters(); |
| 1414 | } |
| 1415 | |
| 1416 | |
| 1417 | void LAllocator::AllocateDoubleRegisters() { |
| 1418 | HPhase phase("Allocate double registers", this); |
| 1419 | num_registers_ = DoubleRegister::kNumAllocatableRegisters; |
| 1420 | mode_ = DOUBLE_REGISTERS; |
| 1421 | AllocateRegisters(); |
| 1422 | } |
| 1423 | |
| 1424 | |
| 1425 | void LAllocator::AllocateRegisters() { |
| 1426 | ASSERT(mode_ != NONE); |
| 1427 | reusable_slots_.Clear(); |
| 1428 | |
| 1429 | for (int i = 0; i < live_ranges_.length(); ++i) { |
| 1430 | if (live_ranges_[i] != NULL) { |
| 1431 | if (RequiredRegisterKind(live_ranges_[i]->id()) == mode_) { |
| 1432 | AddToUnhandledUnsorted(live_ranges_[i]); |
| 1433 | } |
| 1434 | } |
| 1435 | } |
| 1436 | SortUnhandled(); |
| 1437 | ASSERT(UnhandledIsSorted()); |
| 1438 | |
| 1439 | ASSERT(active_live_ranges_.is_empty()); |
| 1440 | ASSERT(inactive_live_ranges_.is_empty()); |
| 1441 | |
| 1442 | if (mode_ == DOUBLE_REGISTERS) { |
| 1443 | for (int i = 0; i < fixed_double_live_ranges_.length(); ++i) { |
| 1444 | LiveRange* current = fixed_double_live_ranges_.at(i); |
| 1445 | if (current != NULL) { |
| 1446 | AddToInactive(current); |
| 1447 | } |
| 1448 | } |
| 1449 | } else { |
| 1450 | for (int i = 0; i < fixed_live_ranges_.length(); ++i) { |
| 1451 | LiveRange* current = fixed_live_ranges_.at(i); |
| 1452 | if (current != NULL) { |
| 1453 | AddToInactive(current); |
| 1454 | } |
| 1455 | } |
| 1456 | } |
| 1457 | |
| 1458 | while (!unhandled_live_ranges_.is_empty()) { |
| 1459 | ASSERT(UnhandledIsSorted()); |
| 1460 | LiveRange* current = unhandled_live_ranges_.RemoveLast(); |
| 1461 | ASSERT(UnhandledIsSorted()); |
| 1462 | LifetimePosition position = current->Start(); |
| 1463 | TraceAlloc("Processing interval %d start=%d\n", |
| 1464 | current->id(), |
| 1465 | position.Value()); |
| 1466 | |
| 1467 | if (current->HasAllocatedSpillOperand()) { |
| 1468 | TraceAlloc("Live range %d already has a spill operand\n", current->id()); |
| 1469 | LifetimePosition next_pos = position; |
| 1470 | if (chunk_->IsGapAt(next_pos.InstructionIndex())) { |
| 1471 | next_pos = next_pos.NextInstruction(); |
| 1472 | } |
| 1473 | UsePosition* pos = current->NextUsePositionRegisterIsBeneficial(next_pos); |
| 1474 | // If the range already has a spill operand and it doesn't need a |
| 1475 | // register immediately, split it and spill the first part of the range. |
| 1476 | if (pos == NULL) { |
| 1477 | Spill(current); |
| 1478 | continue; |
| 1479 | } else if (pos->pos().Value() > |
| 1480 | current->Start().NextInstruction().Value()) { |
| 1481 | // Do not spill live range eagerly if use position that can benefit from |
| 1482 | // the register is too close to the start of live range. |
| 1483 | SpillBetween(current, current->Start(), pos->pos()); |
| 1484 | ASSERT(UnhandledIsSorted()); |
| 1485 | continue; |
| 1486 | } |
| 1487 | } |
| 1488 | |
| 1489 | for (int i = 0; i < active_live_ranges_.length(); ++i) { |
| 1490 | LiveRange* cur_active = active_live_ranges_.at(i); |
| 1491 | if (cur_active->End().Value() <= position.Value()) { |
| 1492 | ActiveToHandled(cur_active); |
| 1493 | --i; // The live range was removed from the list of active live ranges. |
| 1494 | } else if (!cur_active->Covers(position)) { |
| 1495 | ActiveToInactive(cur_active); |
| 1496 | --i; // The live range was removed from the list of active live ranges. |
| 1497 | } |
| 1498 | } |
| 1499 | |
| 1500 | for (int i = 0; i < inactive_live_ranges_.length(); ++i) { |
| 1501 | LiveRange* cur_inactive = inactive_live_ranges_.at(i); |
| 1502 | if (cur_inactive->End().Value() <= position.Value()) { |
| 1503 | InactiveToHandled(cur_inactive); |
| 1504 | --i; // Live range was removed from the list of inactive live ranges. |
| 1505 | } else if (cur_inactive->Covers(position)) { |
| 1506 | InactiveToActive(cur_inactive); |
| 1507 | --i; // Live range was removed from the list of inactive live ranges. |
| 1508 | } |
| 1509 | } |
| 1510 | |
| 1511 | ASSERT(!current->HasRegisterAssigned() && !current->IsSpilled()); |
| 1512 | |
| 1513 | bool result = TryAllocateFreeReg(current); |
| 1514 | if (!result) { |
| 1515 | AllocateBlockedReg(current); |
| 1516 | } |
| 1517 | |
| 1518 | if (current->HasRegisterAssigned()) { |
| 1519 | AddToActive(current); |
| 1520 | } |
| 1521 | } |
| 1522 | |
| 1523 | active_live_ranges_.Clear(); |
| 1524 | inactive_live_ranges_.Clear(); |
| 1525 | } |
| 1526 | |
| 1527 | |
| 1528 | void LAllocator::Setup() { |
| 1529 | LConstantOperand::SetupCache(); |
| 1530 | LStackSlot::SetupCache(); |
| 1531 | LDoubleStackSlot::SetupCache(); |
| 1532 | LRegister::SetupCache(); |
| 1533 | LDoubleRegister::SetupCache(); |
| 1534 | } |
| 1535 | |
| 1536 | |
| 1537 | const char* LAllocator::RegisterName(int allocation_index) { |
| 1538 | ASSERT(mode_ != NONE); |
| 1539 | if (mode_ == GENERAL_REGISTERS) { |
| 1540 | return Register::AllocationIndexToString(allocation_index); |
| 1541 | } else { |
| 1542 | return DoubleRegister::AllocationIndexToString(allocation_index); |
| 1543 | } |
| 1544 | } |
| 1545 | |
| 1546 | |
| 1547 | void LAllocator::TraceAlloc(const char* msg, ...) { |
| 1548 | if (FLAG_trace_alloc) { |
| 1549 | va_list arguments; |
| 1550 | va_start(arguments, msg); |
| 1551 | OS::VPrint(msg, arguments); |
| 1552 | va_end(arguments); |
| 1553 | } |
| 1554 | } |
| 1555 | |
| 1556 | |
| 1557 | void LAllocator::RecordUse(HValue* value, LUnallocated* operand) { |
| 1558 | operand->set_virtual_register(value->id()); |
| 1559 | current_summary()->AddInput(operand); |
| 1560 | } |
| 1561 | |
| 1562 | |
| 1563 | bool LAllocator::HasTaggedValue(int virtual_register) const { |
| 1564 | HValue* value = graph()->LookupValue(virtual_register); |
| 1565 | if (value == NULL) return false; |
| 1566 | return value->representation().IsTagged(); |
| 1567 | } |
| 1568 | |
| 1569 | |
| 1570 | RegisterKind LAllocator::RequiredRegisterKind(int virtual_register) const { |
Steve Block | 9fac840 | 2011-05-12 15:51:54 +0100 | [diff] [blame^] | 1571 | if (virtual_register < first_artificial_register_) { |
| 1572 | HValue* value = graph()->LookupValue(virtual_register); |
| 1573 | if (value != NULL && value->representation().IsDouble()) { |
| 1574 | return DOUBLE_REGISTERS; |
| 1575 | } |
| 1576 | } else if (double_artificial_registers_.Contains( |
| 1577 | virtual_register - first_artificial_register_)) { |
Ben Murdoch | b0fe162 | 2011-05-05 13:52:32 +0100 | [diff] [blame] | 1578 | return DOUBLE_REGISTERS; |
| 1579 | } |
Steve Block | 9fac840 | 2011-05-12 15:51:54 +0100 | [diff] [blame^] | 1580 | |
Ben Murdoch | b0fe162 | 2011-05-05 13:52:32 +0100 | [diff] [blame] | 1581 | return GENERAL_REGISTERS; |
| 1582 | } |
| 1583 | |
| 1584 | |
| 1585 | void LAllocator::MarkAsCall() { |
Steve Block | 9fac840 | 2011-05-12 15:51:54 +0100 | [diff] [blame^] | 1586 | // Call instructions can use only fixed registers as |
| 1587 | // temporaries and outputs because all registers |
| 1588 | // are blocked by the calling convention. |
| 1589 | // Inputs can use either fixed register or have a short lifetime (be |
| 1590 | // used at start of the instruction). |
| 1591 | InstructionSummary* summary = current_summary(); |
| 1592 | #ifdef DEBUG |
| 1593 | ASSERT(summary->Output() == NULL || |
| 1594 | LUnallocated::cast(summary->Output())->HasFixedPolicy() || |
| 1595 | !LUnallocated::cast(summary->Output())->HasRegisterPolicy()); |
| 1596 | for (int i = 0; i < summary->InputCount(); i++) { |
| 1597 | ASSERT(LUnallocated::cast(summary->InputAt(i))->HasFixedPolicy() || |
| 1598 | LUnallocated::cast(summary->InputAt(i))->IsUsedAtStart() || |
| 1599 | !LUnallocated::cast(summary->InputAt(i))->HasRegisterPolicy()); |
| 1600 | } |
| 1601 | for (int i = 0; i < summary->TempCount(); i++) { |
| 1602 | ASSERT(LUnallocated::cast(summary->TempAt(i))->HasFixedPolicy() || |
| 1603 | !LUnallocated::cast(summary->TempAt(i))->HasRegisterPolicy()); |
| 1604 | } |
| 1605 | #endif |
| 1606 | summary->MarkAsCall(); |
Ben Murdoch | b0fe162 | 2011-05-05 13:52:32 +0100 | [diff] [blame] | 1607 | } |
| 1608 | |
| 1609 | |
| 1610 | void LAllocator::RecordDefinition(HInstruction* instr, LUnallocated* operand) { |
| 1611 | operand->set_virtual_register(instr->id()); |
| 1612 | current_summary()->SetOutput(operand); |
| 1613 | } |
| 1614 | |
| 1615 | |
| 1616 | void LAllocator::RecordTemporary(LUnallocated* operand) { |
| 1617 | ASSERT(next_virtual_register_ < LUnallocated::kMaxVirtualRegisters); |
| 1618 | if (!operand->HasFixedPolicy()) { |
| 1619 | operand->set_virtual_register(next_virtual_register_++); |
| 1620 | } |
| 1621 | current_summary()->AddTemp(operand); |
| 1622 | } |
| 1623 | |
| 1624 | |
| 1625 | int LAllocator::max_initial_value_ids() { |
| 1626 | return LUnallocated::kMaxVirtualRegisters / 32; |
| 1627 | } |
| 1628 | |
| 1629 | |
| 1630 | void LAllocator::BeginInstruction() { |
| 1631 | if (next_summary_ == NULL) { |
| 1632 | next_summary_ = new InstructionSummary(); |
| 1633 | } |
| 1634 | summary_stack_.Add(next_summary_); |
| 1635 | next_summary_ = NULL; |
| 1636 | } |
| 1637 | |
| 1638 | |
| 1639 | void LAllocator::SummarizeInstruction(int index) { |
| 1640 | InstructionSummary* sum = summary_stack_.RemoveLast(); |
| 1641 | if (summaries_.length() <= index) { |
| 1642 | summaries_.AddBlock(NULL, index + 1 - summaries_.length()); |
| 1643 | } |
| 1644 | ASSERT(summaries_[index] == NULL); |
| 1645 | if (sum->Output() != NULL || sum->InputCount() > 0 || sum->TempCount() > 0) { |
| 1646 | summaries_[index] = sum; |
| 1647 | } else { |
| 1648 | next_summary_ = sum; |
| 1649 | } |
| 1650 | } |
| 1651 | |
| 1652 | |
| 1653 | void LAllocator::OmitInstruction() { |
| 1654 | summary_stack_.RemoveLast(); |
| 1655 | } |
| 1656 | |
| 1657 | |
| 1658 | void LAllocator::AddToActive(LiveRange* range) { |
| 1659 | TraceAlloc("Add live range %d to active\n", range->id()); |
| 1660 | active_live_ranges_.Add(range); |
| 1661 | } |
| 1662 | |
| 1663 | |
| 1664 | void LAllocator::AddToInactive(LiveRange* range) { |
| 1665 | TraceAlloc("Add live range %d to inactive\n", range->id()); |
| 1666 | inactive_live_ranges_.Add(range); |
| 1667 | } |
| 1668 | |
| 1669 | |
| 1670 | void LAllocator::AddToUnhandledSorted(LiveRange* range) { |
| 1671 | if (range == NULL || range->IsEmpty()) return; |
| 1672 | ASSERT(!range->HasRegisterAssigned() && !range->IsSpilled()); |
| 1673 | for (int i = unhandled_live_ranges_.length() - 1; i >= 0; --i) { |
| 1674 | LiveRange* cur_range = unhandled_live_ranges_.at(i); |
| 1675 | if (range->ShouldBeAllocatedBefore(cur_range)) { |
| 1676 | TraceAlloc("Add live range %d to unhandled at %d\n", range->id(), i + 1); |
| 1677 | unhandled_live_ranges_.InsertAt(i + 1, range); |
| 1678 | ASSERT(UnhandledIsSorted()); |
| 1679 | return; |
| 1680 | } |
| 1681 | } |
| 1682 | TraceAlloc("Add live range %d to unhandled at start\n", range->id()); |
| 1683 | unhandled_live_ranges_.InsertAt(0, range); |
| 1684 | ASSERT(UnhandledIsSorted()); |
| 1685 | } |
| 1686 | |
| 1687 | |
| 1688 | void LAllocator::AddToUnhandledUnsorted(LiveRange* range) { |
| 1689 | if (range == NULL || range->IsEmpty()) return; |
| 1690 | ASSERT(!range->HasRegisterAssigned() && !range->IsSpilled()); |
| 1691 | TraceAlloc("Add live range %d to unhandled unsorted at end\n", range->id()); |
| 1692 | unhandled_live_ranges_.Add(range); |
| 1693 | } |
| 1694 | |
| 1695 | |
| 1696 | static int UnhandledSortHelper(LiveRange* const* a, LiveRange* const* b) { |
| 1697 | ASSERT(!(*a)->ShouldBeAllocatedBefore(*b) || |
| 1698 | !(*b)->ShouldBeAllocatedBefore(*a)); |
| 1699 | if ((*a)->ShouldBeAllocatedBefore(*b)) return 1; |
| 1700 | if ((*b)->ShouldBeAllocatedBefore(*a)) return -1; |
| 1701 | return (*a)->id() - (*b)->id(); |
| 1702 | } |
| 1703 | |
| 1704 | |
| 1705 | // Sort the unhandled live ranges so that the ranges to be processed first are |
| 1706 | // at the end of the array list. This is convenient for the register allocation |
| 1707 | // algorithm because it is efficient to remove elements from the end. |
| 1708 | void LAllocator::SortUnhandled() { |
| 1709 | TraceAlloc("Sort unhandled\n"); |
| 1710 | unhandled_live_ranges_.Sort(&UnhandledSortHelper); |
| 1711 | } |
| 1712 | |
| 1713 | |
| 1714 | bool LAllocator::UnhandledIsSorted() { |
| 1715 | int len = unhandled_live_ranges_.length(); |
| 1716 | for (int i = 1; i < len; i++) { |
| 1717 | LiveRange* a = unhandled_live_ranges_.at(i - 1); |
| 1718 | LiveRange* b = unhandled_live_ranges_.at(i); |
| 1719 | if (a->Start().Value() < b->Start().Value()) return false; |
| 1720 | } |
| 1721 | return true; |
| 1722 | } |
| 1723 | |
| 1724 | |
| 1725 | void LAllocator::FreeSpillSlot(LiveRange* range) { |
| 1726 | // Check that we are the last range. |
| 1727 | if (range->next() != NULL) return; |
| 1728 | |
| 1729 | if (!range->TopLevel()->HasAllocatedSpillOperand()) return; |
| 1730 | |
| 1731 | int index = range->TopLevel()->GetSpillOperand()->index(); |
| 1732 | if (index >= 0) { |
| 1733 | reusable_slots_.Add(range); |
| 1734 | } |
| 1735 | } |
| 1736 | |
| 1737 | |
| 1738 | LOperand* LAllocator::TryReuseSpillSlot(LiveRange* range) { |
| 1739 | if (reusable_slots_.is_empty()) return NULL; |
| 1740 | if (reusable_slots_.first()->End().Value() > |
| 1741 | range->TopLevel()->Start().Value()) { |
| 1742 | return NULL; |
| 1743 | } |
| 1744 | LOperand* result = reusable_slots_.first()->TopLevel()->GetSpillOperand(); |
| 1745 | reusable_slots_.Remove(0); |
| 1746 | return result; |
| 1747 | } |
| 1748 | |
| 1749 | |
| 1750 | void LAllocator::ActiveToHandled(LiveRange* range) { |
| 1751 | ASSERT(active_live_ranges_.Contains(range)); |
| 1752 | active_live_ranges_.RemoveElement(range); |
| 1753 | TraceAlloc("Moving live range %d from active to handled\n", range->id()); |
| 1754 | FreeSpillSlot(range); |
| 1755 | } |
| 1756 | |
| 1757 | |
| 1758 | void LAllocator::ActiveToInactive(LiveRange* range) { |
| 1759 | ASSERT(active_live_ranges_.Contains(range)); |
| 1760 | active_live_ranges_.RemoveElement(range); |
| 1761 | inactive_live_ranges_.Add(range); |
| 1762 | TraceAlloc("Moving live range %d from active to inactive\n", range->id()); |
| 1763 | } |
| 1764 | |
| 1765 | |
| 1766 | void LAllocator::InactiveToHandled(LiveRange* range) { |
| 1767 | ASSERT(inactive_live_ranges_.Contains(range)); |
| 1768 | inactive_live_ranges_.RemoveElement(range); |
| 1769 | TraceAlloc("Moving live range %d from inactive to handled\n", range->id()); |
| 1770 | FreeSpillSlot(range); |
| 1771 | } |
| 1772 | |
| 1773 | |
| 1774 | void LAllocator::InactiveToActive(LiveRange* range) { |
| 1775 | ASSERT(inactive_live_ranges_.Contains(range)); |
| 1776 | inactive_live_ranges_.RemoveElement(range); |
| 1777 | active_live_ranges_.Add(range); |
| 1778 | TraceAlloc("Moving live range %d from inactive to active\n", range->id()); |
| 1779 | } |
| 1780 | |
| 1781 | |
| 1782 | // TryAllocateFreeReg and AllocateBlockedReg assume this |
| 1783 | // when allocating local arrays. |
| 1784 | STATIC_ASSERT(DoubleRegister::kNumAllocatableRegisters >= |
| 1785 | Register::kNumAllocatableRegisters); |
| 1786 | |
| 1787 | |
| 1788 | bool LAllocator::TryAllocateFreeReg(LiveRange* current) { |
| 1789 | LifetimePosition free_until_pos[DoubleRegister::kNumAllocatableRegisters]; |
| 1790 | |
| 1791 | for (int i = 0; i < DoubleRegister::kNumAllocatableRegisters; i++) { |
| 1792 | free_until_pos[i] = LifetimePosition::MaxPosition(); |
| 1793 | } |
| 1794 | |
| 1795 | for (int i = 0; i < active_live_ranges_.length(); ++i) { |
| 1796 | LiveRange* cur_active = active_live_ranges_.at(i); |
| 1797 | free_until_pos[cur_active->assigned_register()] = |
| 1798 | LifetimePosition::FromInstructionIndex(0); |
| 1799 | } |
| 1800 | |
| 1801 | for (int i = 0; i < inactive_live_ranges_.length(); ++i) { |
| 1802 | LiveRange* cur_inactive = inactive_live_ranges_.at(i); |
| 1803 | ASSERT(cur_inactive->End().Value() > current->Start().Value()); |
| 1804 | LifetimePosition next_intersection = |
| 1805 | cur_inactive->FirstIntersection(current); |
| 1806 | if (!next_intersection.IsValid()) continue; |
| 1807 | int cur_reg = cur_inactive->assigned_register(); |
| 1808 | free_until_pos[cur_reg] = Min(free_until_pos[cur_reg], next_intersection); |
| 1809 | } |
| 1810 | |
| 1811 | UsePosition* hinted_use = current->FirstPosWithHint(); |
| 1812 | if (hinted_use != NULL) { |
| 1813 | LOperand* hint = hinted_use->hint(); |
| 1814 | if (hint->IsRegister() || hint->IsDoubleRegister()) { |
| 1815 | int register_index = hint->index(); |
| 1816 | TraceAlloc( |
| 1817 | "Found reg hint %s (free until [%d) for live range %d (end %d[).\n", |
| 1818 | RegisterName(register_index), |
| 1819 | free_until_pos[register_index].Value(), |
| 1820 | current->id(), |
| 1821 | current->End().Value()); |
| 1822 | |
| 1823 | // The desired register is free until the end of the current live range. |
| 1824 | if (free_until_pos[register_index].Value() >= current->End().Value()) { |
| 1825 | TraceAlloc("Assigning preferred reg %s to live range %d\n", |
| 1826 | RegisterName(register_index), |
| 1827 | current->id()); |
| 1828 | current->set_assigned_register(register_index, mode_); |
| 1829 | return true; |
| 1830 | } |
| 1831 | } |
| 1832 | } |
| 1833 | |
| 1834 | // Find the register which stays free for the longest time. |
| 1835 | int reg = 0; |
| 1836 | for (int i = 1; i < RegisterCount(); ++i) { |
| 1837 | if (free_until_pos[i].Value() > free_until_pos[reg].Value()) { |
| 1838 | reg = i; |
| 1839 | } |
| 1840 | } |
| 1841 | |
| 1842 | LifetimePosition pos = free_until_pos[reg]; |
| 1843 | |
| 1844 | if (pos.Value() <= current->Start().Value()) { |
| 1845 | // All registers are blocked. |
| 1846 | return false; |
| 1847 | } |
| 1848 | |
| 1849 | if (pos.Value() < current->End().Value()) { |
| 1850 | // Register reg is available at the range start but becomes blocked before |
| 1851 | // the range end. Split current at position where it becomes blocked. |
| 1852 | LiveRange* tail = SplitAt(current, pos); |
| 1853 | AddToUnhandledSorted(tail); |
| 1854 | } |
| 1855 | |
| 1856 | |
| 1857 | // Register reg is available at the range start and is free until |
| 1858 | // the range end. |
| 1859 | ASSERT(pos.Value() >= current->End().Value()); |
| 1860 | TraceAlloc("Assigning free reg %s to live range %d\n", |
| 1861 | RegisterName(reg), |
| 1862 | current->id()); |
| 1863 | current->set_assigned_register(reg, mode_); |
| 1864 | |
| 1865 | return true; |
| 1866 | } |
| 1867 | |
| 1868 | |
| 1869 | void LAllocator::AllocateBlockedReg(LiveRange* current) { |
| 1870 | UsePosition* register_use = current->NextRegisterPosition(current->Start()); |
| 1871 | if (register_use == NULL) { |
| 1872 | // There is no use in the current live range that requires a register. |
| 1873 | // We can just spill it. |
| 1874 | Spill(current); |
| 1875 | return; |
| 1876 | } |
| 1877 | |
| 1878 | |
| 1879 | LifetimePosition use_pos[DoubleRegister::kNumAllocatableRegisters]; |
| 1880 | LifetimePosition block_pos[DoubleRegister::kNumAllocatableRegisters]; |
| 1881 | |
| 1882 | for (int i = 0; i < DoubleRegister::kNumAllocatableRegisters; i++) { |
| 1883 | use_pos[i] = block_pos[i] = LifetimePosition::MaxPosition(); |
| 1884 | } |
| 1885 | |
| 1886 | for (int i = 0; i < active_live_ranges_.length(); ++i) { |
| 1887 | LiveRange* range = active_live_ranges_[i]; |
| 1888 | int cur_reg = range->assigned_register(); |
| 1889 | if (range->IsFixed() || !range->CanBeSpilled(current->Start())) { |
| 1890 | block_pos[cur_reg] = use_pos[cur_reg] = |
| 1891 | LifetimePosition::FromInstructionIndex(0); |
| 1892 | } else { |
| 1893 | UsePosition* next_use = range->NextUsePositionRegisterIsBeneficial( |
| 1894 | current->Start()); |
| 1895 | if (next_use == NULL) { |
| 1896 | use_pos[cur_reg] = range->End(); |
| 1897 | } else { |
| 1898 | use_pos[cur_reg] = next_use->pos(); |
| 1899 | } |
| 1900 | } |
| 1901 | } |
| 1902 | |
| 1903 | for (int i = 0; i < inactive_live_ranges_.length(); ++i) { |
| 1904 | LiveRange* range = inactive_live_ranges_.at(i); |
| 1905 | ASSERT(range->End().Value() > current->Start().Value()); |
| 1906 | LifetimePosition next_intersection = range->FirstIntersection(current); |
| 1907 | if (!next_intersection.IsValid()) continue; |
| 1908 | int cur_reg = range->assigned_register(); |
| 1909 | if (range->IsFixed()) { |
| 1910 | block_pos[cur_reg] = Min(block_pos[cur_reg], next_intersection); |
| 1911 | use_pos[cur_reg] = Min(block_pos[cur_reg], use_pos[cur_reg]); |
| 1912 | } else { |
| 1913 | use_pos[cur_reg] = Min(use_pos[cur_reg], next_intersection); |
| 1914 | } |
| 1915 | } |
| 1916 | |
| 1917 | int reg = 0; |
| 1918 | for (int i = 1; i < RegisterCount(); ++i) { |
| 1919 | if (use_pos[i].Value() > use_pos[reg].Value()) { |
| 1920 | reg = i; |
| 1921 | } |
| 1922 | } |
| 1923 | |
| 1924 | LifetimePosition pos = use_pos[reg]; |
| 1925 | |
| 1926 | if (pos.Value() < register_use->pos().Value()) { |
| 1927 | // All registers are blocked before the first use that requires a register. |
| 1928 | // Spill starting part of live range up to that use. |
| 1929 | // |
| 1930 | // Corner case: the first use position is equal to the start of the range. |
| 1931 | // In this case we have nothing to spill and SpillBetween will just return |
| 1932 | // this range to the list of unhandled ones. This will lead to the infinite |
| 1933 | // loop. |
| 1934 | ASSERT(current->Start().Value() < register_use->pos().Value()); |
| 1935 | SpillBetween(current, current->Start(), register_use->pos()); |
| 1936 | return; |
| 1937 | } |
| 1938 | |
| 1939 | if (block_pos[reg].Value() < current->End().Value()) { |
| 1940 | // Register becomes blocked before the current range end. Split before that |
| 1941 | // position. |
| 1942 | LiveRange* tail = SplitBetween(current, |
| 1943 | current->Start(), |
| 1944 | block_pos[reg].InstructionStart()); |
| 1945 | AddToUnhandledSorted(tail); |
| 1946 | } |
| 1947 | |
| 1948 | // Register reg is not blocked for the whole range. |
| 1949 | ASSERT(block_pos[reg].Value() >= current->End().Value()); |
| 1950 | TraceAlloc("Assigning blocked reg %s to live range %d\n", |
| 1951 | RegisterName(reg), |
| 1952 | current->id()); |
| 1953 | current->set_assigned_register(reg, mode_); |
| 1954 | |
| 1955 | // This register was not free. Thus we need to find and spill |
| 1956 | // parts of active and inactive live regions that use the same register |
| 1957 | // at the same lifetime positions as current. |
| 1958 | SplitAndSpillIntersecting(current); |
| 1959 | } |
| 1960 | |
| 1961 | |
| 1962 | void LAllocator::SplitAndSpillIntersecting(LiveRange* current) { |
| 1963 | ASSERT(current->HasRegisterAssigned()); |
| 1964 | int reg = current->assigned_register(); |
| 1965 | LifetimePosition split_pos = current->Start(); |
| 1966 | for (int i = 0; i < active_live_ranges_.length(); ++i) { |
| 1967 | LiveRange* range = active_live_ranges_[i]; |
| 1968 | if (range->assigned_register() == reg) { |
| 1969 | UsePosition* next_pos = range->NextRegisterPosition(current->Start()); |
| 1970 | if (next_pos == NULL) { |
| 1971 | SpillAfter(range, split_pos); |
| 1972 | } else { |
| 1973 | SpillBetween(range, split_pos, next_pos->pos()); |
| 1974 | } |
| 1975 | ActiveToHandled(range); |
| 1976 | --i; |
| 1977 | } |
| 1978 | } |
| 1979 | |
| 1980 | for (int i = 0; i < inactive_live_ranges_.length(); ++i) { |
| 1981 | LiveRange* range = inactive_live_ranges_[i]; |
| 1982 | ASSERT(range->End().Value() > current->Start().Value()); |
| 1983 | if (range->assigned_register() == reg && !range->IsFixed()) { |
| 1984 | LifetimePosition next_intersection = range->FirstIntersection(current); |
| 1985 | if (next_intersection.IsValid()) { |
| 1986 | UsePosition* next_pos = range->NextRegisterPosition(current->Start()); |
| 1987 | if (next_pos == NULL) { |
| 1988 | SpillAfter(range, split_pos); |
| 1989 | } else { |
| 1990 | next_intersection = Min(next_intersection, next_pos->pos()); |
| 1991 | SpillBetween(range, split_pos, next_intersection); |
| 1992 | } |
| 1993 | InactiveToHandled(range); |
| 1994 | --i; |
| 1995 | } |
| 1996 | } |
| 1997 | } |
| 1998 | } |
| 1999 | |
| 2000 | |
| 2001 | bool LAllocator::IsBlockBoundary(LifetimePosition pos) { |
| 2002 | return pos.IsInstructionStart() && |
| 2003 | chunk_->instructions()->at(pos.InstructionIndex())->IsLabel(); |
| 2004 | } |
| 2005 | |
| 2006 | |
| 2007 | void LAllocator::AddGapMove(int pos, LiveRange* prev, LiveRange* next) { |
| 2008 | UsePosition* prev_pos = prev->AddUsePosition( |
| 2009 | LifetimePosition::FromInstructionIndex(pos)); |
| 2010 | UsePosition* next_pos = next->AddUsePosition( |
| 2011 | LifetimePosition::FromInstructionIndex(pos)); |
| 2012 | LOperand* prev_operand = prev_pos->operand(); |
| 2013 | LOperand* next_operand = next_pos->operand(); |
| 2014 | LGap* gap = chunk_->GetGapAt(pos); |
| 2015 | gap->GetOrCreateParallelMove(LGap::START)-> |
| 2016 | AddMove(prev_operand, next_operand); |
| 2017 | next_pos->set_hint(prev_operand); |
| 2018 | } |
| 2019 | |
| 2020 | |
| 2021 | LiveRange* LAllocator::SplitAt(LiveRange* range, LifetimePosition pos) { |
| 2022 | ASSERT(!range->IsFixed()); |
| 2023 | TraceAlloc("Splitting live range %d at %d\n", range->id(), pos.Value()); |
| 2024 | |
| 2025 | if (pos.Value() <= range->Start().Value()) return range; |
| 2026 | |
| 2027 | LiveRange* result = LiveRangeFor(next_virtual_register_++); |
| 2028 | range->SplitAt(pos, result); |
| 2029 | return result; |
| 2030 | } |
| 2031 | |
| 2032 | |
| 2033 | LiveRange* LAllocator::SplitBetween(LiveRange* range, |
| 2034 | LifetimePosition start, |
| 2035 | LifetimePosition end) { |
| 2036 | ASSERT(!range->IsFixed()); |
| 2037 | TraceAlloc("Splitting live range %d in position between [%d, %d]\n", |
| 2038 | range->id(), |
| 2039 | start.Value(), |
| 2040 | end.Value()); |
| 2041 | |
| 2042 | LifetimePosition split_pos = FindOptimalSplitPos(start, end); |
| 2043 | ASSERT(split_pos.Value() >= start.Value()); |
| 2044 | return SplitAt(range, split_pos); |
| 2045 | } |
| 2046 | |
| 2047 | |
| 2048 | LifetimePosition LAllocator::FindOptimalSplitPos(LifetimePosition start, |
| 2049 | LifetimePosition end) { |
| 2050 | int start_instr = start.InstructionIndex(); |
| 2051 | int end_instr = end.InstructionIndex(); |
| 2052 | ASSERT(start_instr <= end_instr); |
| 2053 | |
| 2054 | // We have no choice |
| 2055 | if (start_instr == end_instr) return end; |
| 2056 | |
| 2057 | HBasicBlock* end_block = GetBlock(start); |
| 2058 | HBasicBlock* start_block = GetBlock(end); |
| 2059 | |
| 2060 | if (end_block == start_block) { |
| 2061 | // The interval is split in the same basic block. Split at latest possible |
| 2062 | // position. |
| 2063 | return end; |
| 2064 | } |
| 2065 | |
| 2066 | HBasicBlock* block = end_block; |
| 2067 | // Find header of outermost loop. |
| 2068 | while (block->parent_loop_header() != NULL && |
| 2069 | block->parent_loop_header()->block_id() > start_block->block_id()) { |
| 2070 | block = block->parent_loop_header(); |
| 2071 | } |
| 2072 | |
| 2073 | if (block == end_block) return end; |
| 2074 | |
| 2075 | return LifetimePosition::FromInstructionIndex( |
| 2076 | block->first_instruction_index()); |
| 2077 | } |
| 2078 | |
| 2079 | |
| 2080 | void LAllocator::SpillAfter(LiveRange* range, LifetimePosition pos) { |
| 2081 | LiveRange* second_part = SplitAt(range, pos); |
| 2082 | Spill(second_part); |
| 2083 | } |
| 2084 | |
| 2085 | |
| 2086 | void LAllocator::SpillBetween(LiveRange* range, |
| 2087 | LifetimePosition start, |
| 2088 | LifetimePosition end) { |
| 2089 | ASSERT(start.Value() < end.Value()); |
| 2090 | LiveRange* second_part = SplitAt(range, start); |
| 2091 | |
| 2092 | if (second_part->Start().Value() < end.Value()) { |
| 2093 | // The split result intersects with [start, end[. |
| 2094 | // Split it at position between ]start+1, end[, spill the middle part |
| 2095 | // and put the rest to unhandled. |
| 2096 | LiveRange* third_part = SplitBetween( |
| 2097 | second_part, |
| 2098 | second_part->Start().InstructionEnd(), |
| 2099 | end.PrevInstruction().InstructionEnd()); |
| 2100 | |
| 2101 | ASSERT(third_part != second_part); |
| 2102 | |
| 2103 | Spill(second_part); |
| 2104 | AddToUnhandledSorted(third_part); |
| 2105 | } else { |
| 2106 | // The split result does not intersect with [start, end[. |
| 2107 | // Nothing to spill. Just put it to unhandled as whole. |
| 2108 | AddToUnhandledSorted(second_part); |
| 2109 | } |
| 2110 | } |
| 2111 | |
| 2112 | |
| 2113 | void LAllocator::Spill(LiveRange* range) { |
| 2114 | ASSERT(!range->IsSpilled()); |
| 2115 | TraceAlloc("Spilling live range %d\n", range->id()); |
| 2116 | LiveRange* first = range->TopLevel(); |
| 2117 | |
| 2118 | if (!first->HasAllocatedSpillOperand()) { |
| 2119 | LOperand* op = TryReuseSpillSlot(range); |
| 2120 | if (op == NULL) op = chunk_->GetNextSpillSlot(mode_ == DOUBLE_REGISTERS); |
| 2121 | first->SetSpillOperand(op); |
| 2122 | } |
| 2123 | range->MakeSpilled(); |
| 2124 | } |
| 2125 | |
| 2126 | |
| 2127 | int LAllocator::RegisterCount() const { |
| 2128 | return num_registers_; |
| 2129 | } |
| 2130 | |
| 2131 | |
| 2132 | #ifdef DEBUG |
| 2133 | |
| 2134 | |
| 2135 | void LAllocator::Verify() const { |
| 2136 | for (int i = 0; i < live_ranges()->length(); ++i) { |
| 2137 | LiveRange* current = live_ranges()->at(i); |
| 2138 | if (current != NULL) current->Verify(); |
| 2139 | } |
| 2140 | } |
| 2141 | |
| 2142 | |
| 2143 | #endif |
| 2144 | |
| 2145 | |
| 2146 | } } // namespace v8::internal |