Upgrade V8 to version 4.9.385.28
https://chromium.googlesource.com/v8/v8/+/4.9.385.28
FPIIM-449
Change-Id: I4b2e74289d4bf3667f2f3dc8aa2e541f63e26eb4
diff --git a/src/crankshaft/lithium-allocator.cc b/src/crankshaft/lithium-allocator.cc
new file mode 100644
index 0000000..5d05292
--- /dev/null
+++ b/src/crankshaft/lithium-allocator.cc
@@ -0,0 +1,2198 @@
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/crankshaft/lithium-allocator.h"
+
+#include "src/crankshaft/hydrogen.h"
+#include "src/crankshaft/lithium-inl.h"
+#include "src/crankshaft/lithium-allocator-inl.h"
+#include "src/register-configuration.h"
+#include "src/string-stream.h"
+
+namespace v8 {
+namespace internal {
+
+static inline LifetimePosition Min(LifetimePosition a, LifetimePosition b) {
+ return a.Value() < b.Value() ? a : b;
+}
+
+
+static inline LifetimePosition Max(LifetimePosition a, LifetimePosition b) {
+ return a.Value() > b.Value() ? a : b;
+}
+
+
+UsePosition::UsePosition(LifetimePosition pos,
+ LOperand* operand,
+ LOperand* hint)
+ : operand_(operand),
+ hint_(hint),
+ pos_(pos),
+ next_(NULL),
+ requires_reg_(false),
+ register_beneficial_(true) {
+ if (operand_ != NULL && operand_->IsUnallocated()) {
+ LUnallocated* unalloc = LUnallocated::cast(operand_);
+ requires_reg_ = unalloc->HasRegisterPolicy() ||
+ unalloc->HasDoubleRegisterPolicy();
+ register_beneficial_ = !unalloc->HasAnyPolicy();
+ }
+ DCHECK(pos_.IsValid());
+}
+
+
+bool UsePosition::HasHint() const {
+ return hint_ != NULL && !hint_->IsUnallocated();
+}
+
+
+bool UsePosition::RequiresRegister() const {
+ return requires_reg_;
+}
+
+
+bool UsePosition::RegisterIsBeneficial() const {
+ return register_beneficial_;
+}
+
+
+void UseInterval::SplitAt(LifetimePosition pos, Zone* zone) {
+ DCHECK(Contains(pos) && pos.Value() != start().Value());
+ UseInterval* after = new(zone) UseInterval(pos, end_);
+ after->next_ = next_;
+ next_ = after;
+ end_ = pos;
+}
+
+
+#ifdef DEBUG
+
+
+void LiveRange::Verify() const {
+ UsePosition* cur = first_pos_;
+ while (cur != NULL) {
+ DCHECK(Start().Value() <= cur->pos().Value() &&
+ cur->pos().Value() <= End().Value());
+ cur = cur->next();
+ }
+}
+
+
+bool LiveRange::HasOverlap(UseInterval* target) const {
+ UseInterval* current_interval = first_interval_;
+ while (current_interval != NULL) {
+ // Intervals overlap if the start of one is contained in the other.
+ if (current_interval->Contains(target->start()) ||
+ target->Contains(current_interval->start())) {
+ return true;
+ }
+ current_interval = current_interval->next();
+ }
+ return false;
+}
+
+
+#endif
+
+
+LiveRange::LiveRange(int id, Zone* zone)
+ : id_(id),
+ spilled_(false),
+ kind_(UNALLOCATED_REGISTERS),
+ assigned_register_(kInvalidAssignment),
+ last_interval_(NULL),
+ first_interval_(NULL),
+ first_pos_(NULL),
+ parent_(NULL),
+ next_(NULL),
+ current_interval_(NULL),
+ last_processed_use_(NULL),
+ current_hint_operand_(NULL),
+ spill_operand_(new (zone) LOperand()),
+ spill_start_index_(kMaxInt) {}
+
+
+void LiveRange::set_assigned_register(int reg, Zone* zone) {
+ DCHECK(!HasRegisterAssigned() && !IsSpilled());
+ assigned_register_ = reg;
+ ConvertOperands(zone);
+}
+
+
+void LiveRange::MakeSpilled(Zone* zone) {
+ DCHECK(!IsSpilled());
+ DCHECK(TopLevel()->HasAllocatedSpillOperand());
+ spilled_ = true;
+ assigned_register_ = kInvalidAssignment;
+ ConvertOperands(zone);
+}
+
+
+bool LiveRange::HasAllocatedSpillOperand() const {
+ DCHECK(spill_operand_ != NULL);
+ return !spill_operand_->IsIgnored();
+}
+
+
+void LiveRange::SetSpillOperand(LOperand* operand) {
+ DCHECK(!operand->IsUnallocated());
+ DCHECK(spill_operand_ != NULL);
+ DCHECK(spill_operand_->IsIgnored());
+ spill_operand_->ConvertTo(operand->kind(), operand->index());
+}
+
+
+UsePosition* LiveRange::NextUsePosition(LifetimePosition start) {
+ UsePosition* use_pos = last_processed_use_;
+ if (use_pos == NULL) use_pos = first_pos();
+ while (use_pos != NULL && use_pos->pos().Value() < start.Value()) {
+ use_pos = use_pos->next();
+ }
+ last_processed_use_ = use_pos;
+ return use_pos;
+}
+
+
+UsePosition* LiveRange::NextUsePositionRegisterIsBeneficial(
+ LifetimePosition start) {
+ UsePosition* pos = NextUsePosition(start);
+ while (pos != NULL && !pos->RegisterIsBeneficial()) {
+ pos = pos->next();
+ }
+ return pos;
+}
+
+
+UsePosition* LiveRange::PreviousUsePositionRegisterIsBeneficial(
+ LifetimePosition start) {
+ UsePosition* pos = first_pos();
+ UsePosition* prev = NULL;
+ while (pos != NULL && pos->pos().Value() < start.Value()) {
+ if (pos->RegisterIsBeneficial()) prev = pos;
+ pos = pos->next();
+ }
+ return prev;
+}
+
+
+UsePosition* LiveRange::NextRegisterPosition(LifetimePosition start) {
+ UsePosition* pos = NextUsePosition(start);
+ while (pos != NULL && !pos->RequiresRegister()) {
+ pos = pos->next();
+ }
+ return pos;
+}
+
+
+bool LiveRange::CanBeSpilled(LifetimePosition pos) {
+ // We cannot spill a live range that has a use requiring a register
+ // at the current or the immediate next position.
+ UsePosition* use_pos = NextRegisterPosition(pos);
+ if (use_pos == NULL) return true;
+ return
+ use_pos->pos().Value() > pos.NextInstruction().InstructionEnd().Value();
+}
+
+
+LOperand* LiveRange::CreateAssignedOperand(Zone* zone) {
+ LOperand* op = NULL;
+ if (HasRegisterAssigned()) {
+ DCHECK(!IsSpilled());
+ switch (Kind()) {
+ case GENERAL_REGISTERS:
+ op = LRegister::Create(assigned_register(), zone);
+ break;
+ case DOUBLE_REGISTERS:
+ op = LDoubleRegister::Create(assigned_register(), zone);
+ break;
+ default:
+ UNREACHABLE();
+ }
+ } else if (IsSpilled()) {
+ DCHECK(!HasRegisterAssigned());
+ op = TopLevel()->GetSpillOperand();
+ DCHECK(!op->IsUnallocated());
+ } else {
+ LUnallocated* unalloc = new(zone) LUnallocated(LUnallocated::NONE);
+ unalloc->set_virtual_register(id_);
+ op = unalloc;
+ }
+ return op;
+}
+
+
+UseInterval* LiveRange::FirstSearchIntervalForPosition(
+ LifetimePosition position) const {
+ if (current_interval_ == NULL) return first_interval_;
+ if (current_interval_->start().Value() > position.Value()) {
+ current_interval_ = NULL;
+ return first_interval_;
+ }
+ return current_interval_;
+}
+
+
+void LiveRange::AdvanceLastProcessedMarker(
+ UseInterval* to_start_of, LifetimePosition but_not_past) const {
+ if (to_start_of == NULL) return;
+ if (to_start_of->start().Value() > but_not_past.Value()) return;
+ LifetimePosition start =
+ current_interval_ == NULL ? LifetimePosition::Invalid()
+ : current_interval_->start();
+ if (to_start_of->start().Value() > start.Value()) {
+ current_interval_ = to_start_of;
+ }
+}
+
+
+void LiveRange::SplitAt(LifetimePosition position,
+ LiveRange* result,
+ Zone* zone) {
+ DCHECK(Start().Value() < position.Value());
+ DCHECK(result->IsEmpty());
+ // Find the last interval that ends before the position. If the
+ // position is contained in one of the intervals in the chain, we
+ // split that interval and use the first part.
+ UseInterval* current = FirstSearchIntervalForPosition(position);
+
+ // If the split position coincides with the beginning of a use interval
+ // we need to split use positons in a special way.
+ bool split_at_start = false;
+
+ if (current->start().Value() == position.Value()) {
+ // When splitting at start we need to locate the previous use interval.
+ current = first_interval_;
+ }
+
+ while (current != NULL) {
+ if (current->Contains(position)) {
+ current->SplitAt(position, zone);
+ break;
+ }
+ UseInterval* next = current->next();
+ if (next->start().Value() >= position.Value()) {
+ split_at_start = (next->start().Value() == position.Value());
+ break;
+ }
+ current = next;
+ }
+
+ // Partition original use intervals to the two live ranges.
+ UseInterval* before = current;
+ UseInterval* after = before->next();
+ result->last_interval_ = (last_interval_ == before)
+ ? after // Only interval in the range after split.
+ : last_interval_; // Last interval of the original range.
+ result->first_interval_ = after;
+ last_interval_ = before;
+
+ // Find the last use position before the split and the first use
+ // position after it.
+ UsePosition* use_after = first_pos_;
+ UsePosition* use_before = NULL;
+ if (split_at_start) {
+ // The split position coincides with the beginning of a use interval (the
+ // end of a lifetime hole). Use at this position should be attributed to
+ // the split child because split child owns use interval covering it.
+ while (use_after != NULL && use_after->pos().Value() < position.Value()) {
+ use_before = use_after;
+ use_after = use_after->next();
+ }
+ } else {
+ while (use_after != NULL && use_after->pos().Value() <= position.Value()) {
+ use_before = use_after;
+ use_after = use_after->next();
+ }
+ }
+
+ // Partition original use positions to the two live ranges.
+ if (use_before != NULL) {
+ use_before->next_ = NULL;
+ } else {
+ first_pos_ = NULL;
+ }
+ result->first_pos_ = use_after;
+
+ // Discard cached iteration state. It might be pointing
+ // to the use that no longer belongs to this live range.
+ last_processed_use_ = NULL;
+ current_interval_ = NULL;
+
+ // Link the new live range in the chain before any of the other
+ // ranges linked from the range before the split.
+ result->parent_ = (parent_ == NULL) ? this : parent_;
+ result->kind_ = result->parent_->kind_;
+ result->next_ = next_;
+ next_ = result;
+
+#ifdef DEBUG
+ Verify();
+ result->Verify();
+#endif
+}
+
+
+// This implements an ordering on live ranges so that they are ordered by their
+// start positions. This is needed for the correctness of the register
+// allocation algorithm. If two live ranges start at the same offset then there
+// is a tie breaker based on where the value is first used. This part of the
+// ordering is merely a heuristic.
+bool LiveRange::ShouldBeAllocatedBefore(const LiveRange* other) const {
+ LifetimePosition start = Start();
+ LifetimePosition other_start = other->Start();
+ if (start.Value() == other_start.Value()) {
+ UsePosition* pos = first_pos();
+ if (pos == NULL) return false;
+ UsePosition* other_pos = other->first_pos();
+ if (other_pos == NULL) return true;
+ return pos->pos().Value() < other_pos->pos().Value();
+ }
+ return start.Value() < other_start.Value();
+}
+
+
+void LiveRange::ShortenTo(LifetimePosition start) {
+ LAllocator::TraceAlloc("Shorten live range %d to [%d\n", id_, start.Value());
+ DCHECK(first_interval_ != NULL);
+ DCHECK(first_interval_->start().Value() <= start.Value());
+ DCHECK(start.Value() < first_interval_->end().Value());
+ first_interval_->set_start(start);
+}
+
+
+void LiveRange::EnsureInterval(LifetimePosition start,
+ LifetimePosition end,
+ Zone* zone) {
+ LAllocator::TraceAlloc("Ensure live range %d in interval [%d %d[\n",
+ id_,
+ start.Value(),
+ end.Value());
+ LifetimePosition new_end = end;
+ while (first_interval_ != NULL &&
+ first_interval_->start().Value() <= end.Value()) {
+ if (first_interval_->end().Value() > end.Value()) {
+ new_end = first_interval_->end();
+ }
+ first_interval_ = first_interval_->next();
+ }
+
+ UseInterval* new_interval = new(zone) UseInterval(start, new_end);
+ new_interval->next_ = first_interval_;
+ first_interval_ = new_interval;
+ if (new_interval->next() == NULL) {
+ last_interval_ = new_interval;
+ }
+}
+
+
+void LiveRange::AddUseInterval(LifetimePosition start,
+ LifetimePosition end,
+ Zone* zone) {
+ LAllocator::TraceAlloc("Add to live range %d interval [%d %d[\n",
+ id_,
+ start.Value(),
+ end.Value());
+ if (first_interval_ == NULL) {
+ UseInterval* interval = new(zone) UseInterval(start, end);
+ first_interval_ = interval;
+ last_interval_ = interval;
+ } else {
+ if (end.Value() == first_interval_->start().Value()) {
+ first_interval_->set_start(start);
+ } else if (end.Value() < first_interval_->start().Value()) {
+ UseInterval* interval = new(zone) UseInterval(start, end);
+ interval->set_next(first_interval_);
+ first_interval_ = interval;
+ } else {
+ // Order of instruction's processing (see ProcessInstructions) guarantees
+ // that each new use interval either precedes or intersects with
+ // last added interval.
+ DCHECK(start.Value() < first_interval_->end().Value());
+ first_interval_->start_ = Min(start, first_interval_->start_);
+ first_interval_->end_ = Max(end, first_interval_->end_);
+ }
+ }
+}
+
+
+void LiveRange::AddUsePosition(LifetimePosition pos,
+ LOperand* operand,
+ LOperand* hint,
+ Zone* zone) {
+ LAllocator::TraceAlloc("Add to live range %d use position %d\n",
+ id_,
+ pos.Value());
+ UsePosition* use_pos = new(zone) UsePosition(pos, operand, hint);
+ UsePosition* prev_hint = NULL;
+ UsePosition* prev = NULL;
+ UsePosition* current = first_pos_;
+ while (current != NULL && current->pos().Value() < pos.Value()) {
+ prev_hint = current->HasHint() ? current : prev_hint;
+ prev = current;
+ current = current->next();
+ }
+
+ if (prev == NULL) {
+ use_pos->set_next(first_pos_);
+ first_pos_ = use_pos;
+ } else {
+ use_pos->next_ = prev->next_;
+ prev->next_ = use_pos;
+ }
+
+ if (prev_hint == NULL && use_pos->HasHint()) {
+ current_hint_operand_ = hint;
+ }
+}
+
+
+void LiveRange::ConvertOperands(Zone* zone) {
+ LOperand* op = CreateAssignedOperand(zone);
+ UsePosition* use_pos = first_pos();
+ while (use_pos != NULL) {
+ DCHECK(Start().Value() <= use_pos->pos().Value() &&
+ use_pos->pos().Value() <= End().Value());
+
+ if (use_pos->HasOperand()) {
+ DCHECK(op->IsRegister() || op->IsDoubleRegister() ||
+ !use_pos->RequiresRegister());
+ use_pos->operand()->ConvertTo(op->kind(), op->index());
+ }
+ use_pos = use_pos->next();
+ }
+}
+
+
+bool LiveRange::CanCover(LifetimePosition position) const {
+ if (IsEmpty()) return false;
+ return Start().Value() <= position.Value() &&
+ position.Value() < End().Value();
+}
+
+
+bool LiveRange::Covers(LifetimePosition position) {
+ if (!CanCover(position)) return false;
+ UseInterval* start_search = FirstSearchIntervalForPosition(position);
+ for (UseInterval* interval = start_search;
+ interval != NULL;
+ interval = interval->next()) {
+ DCHECK(interval->next() == NULL ||
+ interval->next()->start().Value() >= interval->start().Value());
+ AdvanceLastProcessedMarker(interval, position);
+ if (interval->Contains(position)) return true;
+ if (interval->start().Value() > position.Value()) return false;
+ }
+ return false;
+}
+
+
+LifetimePosition LiveRange::FirstIntersection(LiveRange* other) {
+ UseInterval* b = other->first_interval();
+ if (b == NULL) return LifetimePosition::Invalid();
+ LifetimePosition advance_last_processed_up_to = b->start();
+ UseInterval* a = FirstSearchIntervalForPosition(b->start());
+ while (a != NULL && b != NULL) {
+ if (a->start().Value() > other->End().Value()) break;
+ if (b->start().Value() > End().Value()) break;
+ LifetimePosition cur_intersection = a->Intersect(b);
+ if (cur_intersection.IsValid()) {
+ return cur_intersection;
+ }
+ if (a->start().Value() < b->start().Value()) {
+ a = a->next();
+ if (a == NULL || a->start().Value() > other->End().Value()) break;
+ AdvanceLastProcessedMarker(a, advance_last_processed_up_to);
+ } else {
+ b = b->next();
+ }
+ }
+ return LifetimePosition::Invalid();
+}
+
+
+LAllocator::LAllocator(int num_values, HGraph* graph)
+ : chunk_(NULL),
+ live_in_sets_(graph->blocks()->length(), zone()),
+ live_ranges_(num_values * 2, zone()),
+ fixed_live_ranges_(NULL),
+ fixed_double_live_ranges_(NULL),
+ unhandled_live_ranges_(num_values * 2, zone()),
+ active_live_ranges_(8, zone()),
+ inactive_live_ranges_(8, zone()),
+ reusable_slots_(8, zone()),
+ next_virtual_register_(num_values),
+ first_artificial_register_(num_values),
+ mode_(UNALLOCATED_REGISTERS),
+ num_registers_(-1),
+ graph_(graph),
+ has_osr_entry_(false),
+ allocation_ok_(true) {}
+
+
+void LAllocator::InitializeLivenessAnalysis() {
+ // Initialize the live_in sets for each block to NULL.
+ int block_count = graph_->blocks()->length();
+ live_in_sets_.Initialize(block_count, zone());
+ live_in_sets_.AddBlock(NULL, block_count, zone());
+}
+
+
+BitVector* LAllocator::ComputeLiveOut(HBasicBlock* block) {
+ // Compute live out for the given block, except not including backward
+ // successor edges.
+ BitVector* live_out = new(zone()) BitVector(next_virtual_register_, zone());
+
+ // Process all successor blocks.
+ for (HSuccessorIterator it(block->end()); !it.Done(); it.Advance()) {
+ // Add values live on entry to the successor. Note the successor's
+ // live_in will not be computed yet for backwards edges.
+ HBasicBlock* successor = it.Current();
+ BitVector* live_in = live_in_sets_[successor->block_id()];
+ if (live_in != NULL) live_out->Union(*live_in);
+
+ // All phi input operands corresponding to this successor edge are live
+ // out from this block.
+ int index = successor->PredecessorIndexOf(block);
+ const ZoneList<HPhi*>* phis = successor->phis();
+ for (int i = 0; i < phis->length(); ++i) {
+ HPhi* phi = phis->at(i);
+ if (!phi->OperandAt(index)->IsConstant()) {
+ live_out->Add(phi->OperandAt(index)->id());
+ }
+ }
+ }
+
+ return live_out;
+}
+
+
+void LAllocator::AddInitialIntervals(HBasicBlock* block,
+ BitVector* live_out) {
+ // Add an interval that includes the entire block to the live range for
+ // each live_out value.
+ LifetimePosition start = LifetimePosition::FromInstructionIndex(
+ block->first_instruction_index());
+ LifetimePosition end = LifetimePosition::FromInstructionIndex(
+ block->last_instruction_index()).NextInstruction();
+ BitVector::Iterator iterator(live_out);
+ while (!iterator.Done()) {
+ int operand_index = iterator.Current();
+ LiveRange* range = LiveRangeFor(operand_index);
+ range->AddUseInterval(start, end, zone());
+ iterator.Advance();
+ }
+}
+
+
+int LAllocator::FixedDoubleLiveRangeID(int index) {
+ return -index - 1 - Register::kNumRegisters;
+}
+
+
+LOperand* LAllocator::AllocateFixed(LUnallocated* operand,
+ int pos,
+ bool is_tagged) {
+ TraceAlloc("Allocating fixed reg for op %d\n", operand->virtual_register());
+ DCHECK(operand->HasFixedPolicy());
+ if (operand->HasFixedSlotPolicy()) {
+ operand->ConvertTo(LOperand::STACK_SLOT, operand->fixed_slot_index());
+ } else if (operand->HasFixedRegisterPolicy()) {
+ int reg_index = operand->fixed_register_index();
+ operand->ConvertTo(LOperand::REGISTER, reg_index);
+ } else if (operand->HasFixedDoubleRegisterPolicy()) {
+ int reg_index = operand->fixed_register_index();
+ operand->ConvertTo(LOperand::DOUBLE_REGISTER, reg_index);
+ } else {
+ UNREACHABLE();
+ }
+ if (is_tagged) {
+ TraceAlloc("Fixed reg is tagged at %d\n", pos);
+ LInstruction* instr = InstructionAt(pos);
+ if (instr->HasPointerMap()) {
+ instr->pointer_map()->RecordPointer(operand, chunk()->zone());
+ }
+ }
+ return operand;
+}
+
+
+LiveRange* LAllocator::FixedLiveRangeFor(int index) {
+ DCHECK(index < Register::kNumRegisters);
+ LiveRange* result = fixed_live_ranges_[index];
+ if (result == NULL) {
+ result = new(zone()) LiveRange(FixedLiveRangeID(index), chunk()->zone());
+ DCHECK(result->IsFixed());
+ result->kind_ = GENERAL_REGISTERS;
+ SetLiveRangeAssignedRegister(result, index);
+ fixed_live_ranges_[index] = result;
+ }
+ return result;
+}
+
+
+LiveRange* LAllocator::FixedDoubleLiveRangeFor(int index) {
+ DCHECK(index < DoubleRegister::kMaxNumRegisters);
+ LiveRange* result = fixed_double_live_ranges_[index];
+ if (result == NULL) {
+ result = new(zone()) LiveRange(FixedDoubleLiveRangeID(index),
+ chunk()->zone());
+ DCHECK(result->IsFixed());
+ result->kind_ = DOUBLE_REGISTERS;
+ SetLiveRangeAssignedRegister(result, index);
+ fixed_double_live_ranges_[index] = result;
+ }
+ return result;
+}
+
+
+LiveRange* LAllocator::LiveRangeFor(int index) {
+ if (index >= live_ranges_.length()) {
+ live_ranges_.AddBlock(NULL, index - live_ranges_.length() + 1, zone());
+ }
+ LiveRange* result = live_ranges_[index];
+ if (result == NULL) {
+ result = new(zone()) LiveRange(index, chunk()->zone());
+ live_ranges_[index] = result;
+ }
+ return result;
+}
+
+
+LGap* LAllocator::GetLastGap(HBasicBlock* block) {
+ int last_instruction = block->last_instruction_index();
+ int index = chunk_->NearestGapPos(last_instruction);
+ return GapAt(index);
+}
+
+
+HPhi* LAllocator::LookupPhi(LOperand* operand) const {
+ if (!operand->IsUnallocated()) return NULL;
+ int index = LUnallocated::cast(operand)->virtual_register();
+ HValue* instr = graph_->LookupValue(index);
+ if (instr != NULL && instr->IsPhi()) {
+ return HPhi::cast(instr);
+ }
+ return NULL;
+}
+
+
+LiveRange* LAllocator::LiveRangeFor(LOperand* operand) {
+ if (operand->IsUnallocated()) {
+ return LiveRangeFor(LUnallocated::cast(operand)->virtual_register());
+ } else if (operand->IsRegister()) {
+ return FixedLiveRangeFor(operand->index());
+ } else if (operand->IsDoubleRegister()) {
+ return FixedDoubleLiveRangeFor(operand->index());
+ } else {
+ return NULL;
+ }
+}
+
+
+void LAllocator::Define(LifetimePosition position,
+ LOperand* operand,
+ LOperand* hint) {
+ LiveRange* range = LiveRangeFor(operand);
+ if (range == NULL) return;
+
+ if (range->IsEmpty() || range->Start().Value() > position.Value()) {
+ // Can happen if there is a definition without use.
+ range->AddUseInterval(position, position.NextInstruction(), zone());
+ range->AddUsePosition(position.NextInstruction(), NULL, NULL, zone());
+ } else {
+ range->ShortenTo(position);
+ }
+
+ if (operand->IsUnallocated()) {
+ LUnallocated* unalloc_operand = LUnallocated::cast(operand);
+ range->AddUsePosition(position, unalloc_operand, hint, zone());
+ }
+}
+
+
+void LAllocator::Use(LifetimePosition block_start,
+ LifetimePosition position,
+ LOperand* operand,
+ LOperand* hint) {
+ LiveRange* range = LiveRangeFor(operand);
+ if (range == NULL) return;
+ if (operand->IsUnallocated()) {
+ LUnallocated* unalloc_operand = LUnallocated::cast(operand);
+ range->AddUsePosition(position, unalloc_operand, hint, zone());
+ }
+ range->AddUseInterval(block_start, position, zone());
+}
+
+
+void LAllocator::AddConstraintsGapMove(int index,
+ LOperand* from,
+ LOperand* to) {
+ LGap* gap = GapAt(index);
+ LParallelMove* move = gap->GetOrCreateParallelMove(LGap::START,
+ chunk()->zone());
+ if (from->IsUnallocated()) {
+ const ZoneList<LMoveOperands>* move_operands = move->move_operands();
+ for (int i = 0; i < move_operands->length(); ++i) {
+ LMoveOperands cur = move_operands->at(i);
+ LOperand* cur_to = cur.destination();
+ if (cur_to->IsUnallocated()) {
+ if (LUnallocated::cast(cur_to)->virtual_register() ==
+ LUnallocated::cast(from)->virtual_register()) {
+ move->AddMove(cur.source(), to, chunk()->zone());
+ return;
+ }
+ }
+ }
+ }
+ move->AddMove(from, to, chunk()->zone());
+}
+
+
+void LAllocator::MeetRegisterConstraints(HBasicBlock* block) {
+ int start = block->first_instruction_index();
+ int end = block->last_instruction_index();
+ if (start == -1) return;
+ for (int i = start; i <= end; ++i) {
+ if (IsGapAt(i)) {
+ LInstruction* instr = NULL;
+ LInstruction* prev_instr = NULL;
+ if (i < end) instr = InstructionAt(i + 1);
+ if (i > start) prev_instr = InstructionAt(i - 1);
+ MeetConstraintsBetween(prev_instr, instr, i);
+ if (!AllocationOk()) return;
+ }
+ }
+}
+
+
+void LAllocator::MeetConstraintsBetween(LInstruction* first,
+ LInstruction* second,
+ int gap_index) {
+ // Handle fixed temporaries.
+ if (first != NULL) {
+ for (TempIterator it(first); !it.Done(); it.Advance()) {
+ LUnallocated* temp = LUnallocated::cast(it.Current());
+ if (temp->HasFixedPolicy()) {
+ AllocateFixed(temp, gap_index - 1, false);
+ }
+ }
+ }
+
+ // Handle fixed output operand.
+ if (first != NULL && first->Output() != NULL) {
+ LUnallocated* first_output = LUnallocated::cast(first->Output());
+ LiveRange* range = LiveRangeFor(first_output->virtual_register());
+ bool assigned = false;
+ if (first_output->HasFixedPolicy()) {
+ LUnallocated* output_copy = first_output->CopyUnconstrained(
+ chunk()->zone());
+ bool is_tagged = HasTaggedValue(first_output->virtual_register());
+ AllocateFixed(first_output, gap_index, is_tagged);
+
+ // This value is produced on the stack, we never need to spill it.
+ if (first_output->IsStackSlot()) {
+ range->SetSpillOperand(first_output);
+ range->SetSpillStartIndex(gap_index - 1);
+ assigned = true;
+ }
+ chunk_->AddGapMove(gap_index, first_output, output_copy);
+ }
+
+ if (!assigned) {
+ range->SetSpillStartIndex(gap_index);
+
+ // This move to spill operand is not a real use. Liveness analysis
+ // and splitting of live ranges do not account for it.
+ // Thus it should be inserted to a lifetime position corresponding to
+ // the instruction end.
+ LGap* gap = GapAt(gap_index);
+ LParallelMove* move = gap->GetOrCreateParallelMove(LGap::BEFORE,
+ chunk()->zone());
+ move->AddMove(first_output, range->GetSpillOperand(),
+ chunk()->zone());
+ }
+ }
+
+ // Handle fixed input operands of second instruction.
+ if (second != NULL) {
+ for (UseIterator it(second); !it.Done(); it.Advance()) {
+ LUnallocated* cur_input = LUnallocated::cast(it.Current());
+ if (cur_input->HasFixedPolicy()) {
+ LUnallocated* input_copy = cur_input->CopyUnconstrained(
+ chunk()->zone());
+ bool is_tagged = HasTaggedValue(cur_input->virtual_register());
+ AllocateFixed(cur_input, gap_index + 1, is_tagged);
+ AddConstraintsGapMove(gap_index, input_copy, cur_input);
+ } else if (cur_input->HasWritableRegisterPolicy()) {
+ // The live range of writable input registers always goes until the end
+ // of the instruction.
+ DCHECK(!cur_input->IsUsedAtStart());
+
+ LUnallocated* input_copy = cur_input->CopyUnconstrained(
+ chunk()->zone());
+ int vreg = GetVirtualRegister();
+ if (!AllocationOk()) return;
+ cur_input->set_virtual_register(vreg);
+
+ if (RequiredRegisterKind(input_copy->virtual_register()) ==
+ DOUBLE_REGISTERS) {
+ double_artificial_registers_.Add(
+ cur_input->virtual_register() - first_artificial_register_,
+ zone());
+ }
+
+ AddConstraintsGapMove(gap_index, input_copy, cur_input);
+ }
+ }
+ }
+
+ // Handle "output same as input" for second instruction.
+ if (second != NULL && second->Output() != NULL) {
+ LUnallocated* second_output = LUnallocated::cast(second->Output());
+ if (second_output->HasSameAsInputPolicy()) {
+ LUnallocated* cur_input = LUnallocated::cast(second->FirstInput());
+ int output_vreg = second_output->virtual_register();
+ int input_vreg = cur_input->virtual_register();
+
+ LUnallocated* input_copy = cur_input->CopyUnconstrained(
+ chunk()->zone());
+ cur_input->set_virtual_register(second_output->virtual_register());
+ AddConstraintsGapMove(gap_index, input_copy, cur_input);
+
+ if (HasTaggedValue(input_vreg) && !HasTaggedValue(output_vreg)) {
+ int index = gap_index + 1;
+ LInstruction* instr = InstructionAt(index);
+ if (instr->HasPointerMap()) {
+ instr->pointer_map()->RecordPointer(input_copy, chunk()->zone());
+ }
+ } else if (!HasTaggedValue(input_vreg) && HasTaggedValue(output_vreg)) {
+ // The input is assumed to immediately have a tagged representation,
+ // before the pointer map can be used. I.e. the pointer map at the
+ // instruction will include the output operand (whose value at the
+ // beginning of the instruction is equal to the input operand). If
+ // this is not desired, then the pointer map at this instruction needs
+ // to be adjusted manually.
+ }
+ }
+ }
+}
+
+
+void LAllocator::ProcessInstructions(HBasicBlock* block, BitVector* live) {
+ int block_start = block->first_instruction_index();
+ int index = block->last_instruction_index();
+
+ LifetimePosition block_start_position =
+ LifetimePosition::FromInstructionIndex(block_start);
+
+ while (index >= block_start) {
+ LifetimePosition curr_position =
+ LifetimePosition::FromInstructionIndex(index);
+
+ if (IsGapAt(index)) {
+ // We have a gap at this position.
+ LGap* gap = GapAt(index);
+ LParallelMove* move = gap->GetOrCreateParallelMove(LGap::START,
+ chunk()->zone());
+ const ZoneList<LMoveOperands>* move_operands = move->move_operands();
+ for (int i = 0; i < move_operands->length(); ++i) {
+ LMoveOperands* cur = &move_operands->at(i);
+ if (cur->IsIgnored()) continue;
+ LOperand* from = cur->source();
+ LOperand* to = cur->destination();
+ HPhi* phi = LookupPhi(to);
+ LOperand* hint = to;
+ if (phi != NULL) {
+ // This is a phi resolving move.
+ if (!phi->block()->IsLoopHeader()) {
+ hint = LiveRangeFor(phi->id())->current_hint_operand();
+ }
+ } else {
+ if (to->IsUnallocated()) {
+ if (live->Contains(LUnallocated::cast(to)->virtual_register())) {
+ Define(curr_position, to, from);
+ live->Remove(LUnallocated::cast(to)->virtual_register());
+ } else {
+ cur->Eliminate();
+ continue;
+ }
+ } else {
+ Define(curr_position, to, from);
+ }
+ }
+ Use(block_start_position, curr_position, from, hint);
+ if (from->IsUnallocated()) {
+ live->Add(LUnallocated::cast(from)->virtual_register());
+ }
+ }
+ } else {
+ DCHECK(!IsGapAt(index));
+ LInstruction* instr = InstructionAt(index);
+
+ if (instr != NULL) {
+ LOperand* output = instr->Output();
+ if (output != NULL) {
+ if (output->IsUnallocated()) {
+ live->Remove(LUnallocated::cast(output)->virtual_register());
+ }
+ Define(curr_position, output, NULL);
+ }
+
+ if (instr->ClobbersRegisters()) {
+ for (int i = 0; i < Register::kNumRegisters; ++i) {
+ if (Register::from_code(i).IsAllocatable()) {
+ if (output == NULL || !output->IsRegister() ||
+ output->index() != i) {
+ LiveRange* range = FixedLiveRangeFor(i);
+ range->AddUseInterval(curr_position,
+ curr_position.InstructionEnd(), zone());
+ }
+ }
+ }
+ }
+
+ if (instr->ClobbersDoubleRegisters(isolate())) {
+ for (int i = 0; i < DoubleRegister::kMaxNumRegisters; ++i) {
+ if (DoubleRegister::from_code(i).IsAllocatable()) {
+ if (output == NULL || !output->IsDoubleRegister() ||
+ output->index() != i) {
+ LiveRange* range = FixedDoubleLiveRangeFor(i);
+ range->AddUseInterval(curr_position,
+ curr_position.InstructionEnd(), zone());
+ }
+ }
+ }
+ }
+
+ for (UseIterator it(instr); !it.Done(); it.Advance()) {
+ LOperand* input = it.Current();
+
+ LifetimePosition use_pos;
+ if (input->IsUnallocated() &&
+ LUnallocated::cast(input)->IsUsedAtStart()) {
+ use_pos = curr_position;
+ } else {
+ use_pos = curr_position.InstructionEnd();
+ }
+
+ Use(block_start_position, use_pos, input, NULL);
+ if (input->IsUnallocated()) {
+ live->Add(LUnallocated::cast(input)->virtual_register());
+ }
+ }
+
+ for (TempIterator it(instr); !it.Done(); it.Advance()) {
+ LOperand* temp = it.Current();
+ if (instr->ClobbersTemps()) {
+ if (temp->IsRegister()) continue;
+ if (temp->IsUnallocated()) {
+ LUnallocated* temp_unalloc = LUnallocated::cast(temp);
+ if (temp_unalloc->HasFixedPolicy()) {
+ continue;
+ }
+ }
+ }
+ Use(block_start_position, curr_position.InstructionEnd(), temp, NULL);
+ Define(curr_position, temp, NULL);
+
+ if (temp->IsUnallocated()) {
+ LUnallocated* temp_unalloc = LUnallocated::cast(temp);
+ if (temp_unalloc->HasDoubleRegisterPolicy()) {
+ double_artificial_registers_.Add(
+ temp_unalloc->virtual_register() - first_artificial_register_,
+ zone());
+ }
+ }
+ }
+ }
+ }
+
+ index = index - 1;
+ }
+}
+
+
+void LAllocator::ResolvePhis(HBasicBlock* block) {
+ const ZoneList<HPhi*>* phis = block->phis();
+ for (int i = 0; i < phis->length(); ++i) {
+ HPhi* phi = phis->at(i);
+ LUnallocated* phi_operand =
+ new (chunk()->zone()) LUnallocated(LUnallocated::NONE);
+ phi_operand->set_virtual_register(phi->id());
+ for (int j = 0; j < phi->OperandCount(); ++j) {
+ HValue* op = phi->OperandAt(j);
+ LOperand* operand = NULL;
+ if (op->IsConstant() && op->EmitAtUses()) {
+ HConstant* constant = HConstant::cast(op);
+ operand = chunk_->DefineConstantOperand(constant);
+ } else {
+ DCHECK(!op->EmitAtUses());
+ LUnallocated* unalloc =
+ new(chunk()->zone()) LUnallocated(LUnallocated::ANY);
+ unalloc->set_virtual_register(op->id());
+ operand = unalloc;
+ }
+ HBasicBlock* cur_block = block->predecessors()->at(j);
+ // The gap move must be added without any special processing as in
+ // the AddConstraintsGapMove.
+ chunk_->AddGapMove(cur_block->last_instruction_index() - 1,
+ operand,
+ phi_operand);
+
+ // We are going to insert a move before the branch instruction.
+ // Some branch instructions (e.g. loops' back edges)
+ // can potentially cause a GC so they have a pointer map.
+ // By inserting a move we essentially create a copy of a
+ // value which is invisible to PopulatePointerMaps(), because we store
+ // it into a location different from the operand of a live range
+ // covering a branch instruction.
+ // Thus we need to manually record a pointer.
+ LInstruction* branch =
+ InstructionAt(cur_block->last_instruction_index());
+ if (branch->HasPointerMap()) {
+ if (phi->representation().IsTagged() && !phi->type().IsSmi()) {
+ branch->pointer_map()->RecordPointer(phi_operand, chunk()->zone());
+ } else if (!phi->representation().IsDouble()) {
+ branch->pointer_map()->RecordUntagged(phi_operand, chunk()->zone());
+ }
+ }
+ }
+
+ LiveRange* live_range = LiveRangeFor(phi->id());
+ LLabel* label = chunk_->GetLabel(phi->block()->block_id());
+ label->GetOrCreateParallelMove(LGap::START, chunk()->zone())->
+ AddMove(phi_operand, live_range->GetSpillOperand(), chunk()->zone());
+ live_range->SetSpillStartIndex(phi->block()->first_instruction_index());
+ }
+}
+
+
+bool LAllocator::Allocate(LChunk* chunk) {
+ DCHECK(chunk_ == NULL);
+ chunk_ = static_cast<LPlatformChunk*>(chunk);
+ assigned_registers_ =
+ new (chunk->zone()) BitVector(Register::kNumRegisters, chunk->zone());
+ assigned_double_registers_ = new (chunk->zone())
+ BitVector(DoubleRegister::kMaxNumRegisters, chunk->zone());
+ MeetRegisterConstraints();
+ if (!AllocationOk()) return false;
+ ResolvePhis();
+ BuildLiveRanges();
+ AllocateGeneralRegisters();
+ if (!AllocationOk()) return false;
+ AllocateDoubleRegisters();
+ if (!AllocationOk()) return false;
+ PopulatePointerMaps();
+ ConnectRanges();
+ ResolveControlFlow();
+ return true;
+}
+
+
+void LAllocator::MeetRegisterConstraints() {
+ LAllocatorPhase phase("L_Register constraints", this);
+ const ZoneList<HBasicBlock*>* blocks = graph_->blocks();
+ for (int i = 0; i < blocks->length(); ++i) {
+ HBasicBlock* block = blocks->at(i);
+ MeetRegisterConstraints(block);
+ if (!AllocationOk()) return;
+ }
+}
+
+
+void LAllocator::ResolvePhis() {
+ LAllocatorPhase phase("L_Resolve phis", this);
+
+ // Process the blocks in reverse order.
+ const ZoneList<HBasicBlock*>* blocks = graph_->blocks();
+ for (int block_id = blocks->length() - 1; block_id >= 0; --block_id) {
+ HBasicBlock* block = blocks->at(block_id);
+ ResolvePhis(block);
+ }
+}
+
+
+void LAllocator::ResolveControlFlow(LiveRange* range,
+ HBasicBlock* block,
+ HBasicBlock* pred) {
+ LifetimePosition pred_end =
+ LifetimePosition::FromInstructionIndex(pred->last_instruction_index());
+ LifetimePosition cur_start =
+ LifetimePosition::FromInstructionIndex(block->first_instruction_index());
+ LiveRange* pred_cover = NULL;
+ LiveRange* cur_cover = NULL;
+ LiveRange* cur_range = range;
+ while (cur_range != NULL && (cur_cover == NULL || pred_cover == NULL)) {
+ if (cur_range->CanCover(cur_start)) {
+ DCHECK(cur_cover == NULL);
+ cur_cover = cur_range;
+ }
+ if (cur_range->CanCover(pred_end)) {
+ DCHECK(pred_cover == NULL);
+ pred_cover = cur_range;
+ }
+ cur_range = cur_range->next();
+ }
+
+ if (cur_cover->IsSpilled()) return;
+ DCHECK(pred_cover != NULL && cur_cover != NULL);
+ if (pred_cover != cur_cover) {
+ LOperand* pred_op = pred_cover->CreateAssignedOperand(chunk()->zone());
+ LOperand* cur_op = cur_cover->CreateAssignedOperand(chunk()->zone());
+ if (!pred_op->Equals(cur_op)) {
+ LGap* gap = NULL;
+ if (block->predecessors()->length() == 1) {
+ gap = GapAt(block->first_instruction_index());
+ } else {
+ DCHECK(pred->end()->SecondSuccessor() == NULL);
+ gap = GetLastGap(pred);
+
+ // We are going to insert a move before the branch instruction.
+ // Some branch instructions (e.g. loops' back edges)
+ // can potentially cause a GC so they have a pointer map.
+ // By inserting a move we essentially create a copy of a
+ // value which is invisible to PopulatePointerMaps(), because we store
+ // it into a location different from the operand of a live range
+ // covering a branch instruction.
+ // Thus we need to manually record a pointer.
+ LInstruction* branch = InstructionAt(pred->last_instruction_index());
+ if (branch->HasPointerMap()) {
+ if (HasTaggedValue(range->id())) {
+ branch->pointer_map()->RecordPointer(cur_op, chunk()->zone());
+ } else if (!cur_op->IsDoubleStackSlot() &&
+ !cur_op->IsDoubleRegister()) {
+ branch->pointer_map()->RemovePointer(cur_op);
+ }
+ }
+ }
+ gap->GetOrCreateParallelMove(
+ LGap::START, chunk()->zone())->AddMove(pred_op, cur_op,
+ chunk()->zone());
+ }
+ }
+}
+
+
+LParallelMove* LAllocator::GetConnectingParallelMove(LifetimePosition pos) {
+ int index = pos.InstructionIndex();
+ if (IsGapAt(index)) {
+ LGap* gap = GapAt(index);
+ return gap->GetOrCreateParallelMove(
+ pos.IsInstructionStart() ? LGap::START : LGap::END, chunk()->zone());
+ }
+ int gap_pos = pos.IsInstructionStart() ? (index - 1) : (index + 1);
+ return GapAt(gap_pos)->GetOrCreateParallelMove(
+ (gap_pos < index) ? LGap::AFTER : LGap::BEFORE, chunk()->zone());
+}
+
+
+HBasicBlock* LAllocator::GetBlock(LifetimePosition pos) {
+ LGap* gap = GapAt(chunk_->NearestGapPos(pos.InstructionIndex()));
+ return gap->block();
+}
+
+
+void LAllocator::ConnectRanges() {
+ LAllocatorPhase phase("L_Connect ranges", this);
+ for (int i = 0; i < live_ranges()->length(); ++i) {
+ LiveRange* first_range = live_ranges()->at(i);
+ if (first_range == NULL || first_range->parent() != NULL) continue;
+
+ LiveRange* second_range = first_range->next();
+ while (second_range != NULL) {
+ LifetimePosition pos = second_range->Start();
+
+ if (!second_range->IsSpilled()) {
+ // Add gap move if the two live ranges touch and there is no block
+ // boundary.
+ if (first_range->End().Value() == pos.Value()) {
+ bool should_insert = true;
+ if (IsBlockBoundary(pos)) {
+ should_insert = CanEagerlyResolveControlFlow(GetBlock(pos));
+ }
+ if (should_insert) {
+ LParallelMove* move = GetConnectingParallelMove(pos);
+ LOperand* prev_operand = first_range->CreateAssignedOperand(
+ chunk()->zone());
+ LOperand* cur_operand = second_range->CreateAssignedOperand(
+ chunk()->zone());
+ move->AddMove(prev_operand, cur_operand,
+ chunk()->zone());
+ }
+ }
+ }
+
+ first_range = second_range;
+ second_range = second_range->next();
+ }
+ }
+}
+
+
+bool LAllocator::CanEagerlyResolveControlFlow(HBasicBlock* block) const {
+ if (block->predecessors()->length() != 1) return false;
+ return block->predecessors()->first()->block_id() == block->block_id() - 1;
+}
+
+
+void LAllocator::ResolveControlFlow() {
+ LAllocatorPhase phase("L_Resolve control flow", this);
+ const ZoneList<HBasicBlock*>* blocks = graph_->blocks();
+ for (int block_id = 1; block_id < blocks->length(); ++block_id) {
+ HBasicBlock* block = blocks->at(block_id);
+ if (CanEagerlyResolveControlFlow(block)) continue;
+ BitVector* live = live_in_sets_[block->block_id()];
+ BitVector::Iterator iterator(live);
+ while (!iterator.Done()) {
+ int operand_index = iterator.Current();
+ for (int i = 0; i < block->predecessors()->length(); ++i) {
+ HBasicBlock* cur = block->predecessors()->at(i);
+ LiveRange* cur_range = LiveRangeFor(operand_index);
+ ResolveControlFlow(cur_range, block, cur);
+ }
+ iterator.Advance();
+ }
+ }
+}
+
+
+void LAllocator::BuildLiveRanges() {
+ LAllocatorPhase phase("L_Build live ranges", this);
+ InitializeLivenessAnalysis();
+ // Process the blocks in reverse order.
+ const ZoneList<HBasicBlock*>* blocks = graph_->blocks();
+ for (int block_id = blocks->length() - 1; block_id >= 0; --block_id) {
+ HBasicBlock* block = blocks->at(block_id);
+ BitVector* live = ComputeLiveOut(block);
+ // Initially consider all live_out values live for the entire block. We
+ // will shorten these intervals if necessary.
+ AddInitialIntervals(block, live);
+
+ // Process the instructions in reverse order, generating and killing
+ // live values.
+ ProcessInstructions(block, live);
+ // All phi output operands are killed by this block.
+ const ZoneList<HPhi*>* phis = block->phis();
+ for (int i = 0; i < phis->length(); ++i) {
+ // The live range interval already ends at the first instruction of the
+ // block.
+ HPhi* phi = phis->at(i);
+ live->Remove(phi->id());
+
+ LOperand* hint = NULL;
+ LOperand* phi_operand = NULL;
+ LGap* gap = GetLastGap(phi->block()->predecessors()->at(0));
+ LParallelMove* move = gap->GetOrCreateParallelMove(LGap::START,
+ chunk()->zone());
+ for (int j = 0; j < move->move_operands()->length(); ++j) {
+ LOperand* to = move->move_operands()->at(j).destination();
+ if (to->IsUnallocated() &&
+ LUnallocated::cast(to)->virtual_register() == phi->id()) {
+ hint = move->move_operands()->at(j).source();
+ phi_operand = to;
+ break;
+ }
+ }
+ DCHECK(hint != NULL);
+
+ LifetimePosition block_start = LifetimePosition::FromInstructionIndex(
+ block->first_instruction_index());
+ Define(block_start, phi_operand, hint);
+ }
+
+ // Now live is live_in for this block except not including values live
+ // out on backward successor edges.
+ live_in_sets_[block_id] = live;
+
+ // If this block is a loop header go back and patch up the necessary
+ // predecessor blocks.
+ if (block->IsLoopHeader()) {
+ // TODO(kmillikin): Need to be able to get the last block of the loop
+ // in the loop information. Add a live range stretching from the first
+ // loop instruction to the last for each value live on entry to the
+ // header.
+ HBasicBlock* back_edge = block->loop_information()->GetLastBackEdge();
+ BitVector::Iterator iterator(live);
+ LifetimePosition start = LifetimePosition::FromInstructionIndex(
+ block->first_instruction_index());
+ LifetimePosition end = LifetimePosition::FromInstructionIndex(
+ back_edge->last_instruction_index()).NextInstruction();
+ while (!iterator.Done()) {
+ int operand_index = iterator.Current();
+ LiveRange* range = LiveRangeFor(operand_index);
+ range->EnsureInterval(start, end, zone());
+ iterator.Advance();
+ }
+
+ for (int i = block->block_id() + 1; i <= back_edge->block_id(); ++i) {
+ live_in_sets_[i]->Union(*live);
+ }
+ }
+
+#ifdef DEBUG
+ if (block_id == 0) {
+ BitVector::Iterator iterator(live);
+ bool found = false;
+ while (!iterator.Done()) {
+ found = true;
+ int operand_index = iterator.Current();
+ {
+ AllowHandleDereference allow_deref;
+ PrintF("Function: %s\n", chunk_->info()->GetDebugName().get());
+ }
+ PrintF("Value %d used before first definition!\n", operand_index);
+ LiveRange* range = LiveRangeFor(operand_index);
+ PrintF("First use is at %d\n", range->first_pos()->pos().Value());
+ iterator.Advance();
+ }
+ DCHECK(!found);
+ }
+#endif
+ }
+
+ for (int i = 0; i < live_ranges_.length(); ++i) {
+ if (live_ranges_[i] != NULL) {
+ live_ranges_[i]->kind_ = RequiredRegisterKind(live_ranges_[i]->id());
+ }
+ }
+}
+
+
+bool LAllocator::SafePointsAreInOrder() const {
+ const ZoneList<LPointerMap*>* pointer_maps = chunk_->pointer_maps();
+ int safe_point = 0;
+ for (int i = 0; i < pointer_maps->length(); ++i) {
+ LPointerMap* map = pointer_maps->at(i);
+ if (safe_point > map->lithium_position()) return false;
+ safe_point = map->lithium_position();
+ }
+ return true;
+}
+
+
+void LAllocator::PopulatePointerMaps() {
+ LAllocatorPhase phase("L_Populate pointer maps", this);
+ const ZoneList<LPointerMap*>* pointer_maps = chunk_->pointer_maps();
+
+ DCHECK(SafePointsAreInOrder());
+
+ // Iterate over all safe point positions and record a pointer
+ // for all spilled live ranges at this point.
+ int first_safe_point_index = 0;
+ int last_range_start = 0;
+ for (int range_idx = 0; range_idx < live_ranges()->length(); ++range_idx) {
+ LiveRange* range = live_ranges()->at(range_idx);
+ if (range == NULL) continue;
+ // Iterate over the first parts of multi-part live ranges.
+ if (range->parent() != NULL) continue;
+ // Skip non-pointer values.
+ if (!HasTaggedValue(range->id())) continue;
+ // Skip empty live ranges.
+ if (range->IsEmpty()) continue;
+
+ // Find the extent of the range and its children.
+ int start = range->Start().InstructionIndex();
+ int end = 0;
+ for (LiveRange* cur = range; cur != NULL; cur = cur->next()) {
+ LifetimePosition this_end = cur->End();
+ if (this_end.InstructionIndex() > end) end = this_end.InstructionIndex();
+ DCHECK(cur->Start().InstructionIndex() >= start);
+ }
+
+ // Most of the ranges are in order, but not all. Keep an eye on when
+ // they step backwards and reset the first_safe_point_index so we don't
+ // miss any safe points.
+ if (start < last_range_start) {
+ first_safe_point_index = 0;
+ }
+ last_range_start = start;
+
+ // Step across all the safe points that are before the start of this range,
+ // recording how far we step in order to save doing this for the next range.
+ while (first_safe_point_index < pointer_maps->length()) {
+ LPointerMap* map = pointer_maps->at(first_safe_point_index);
+ int safe_point = map->lithium_position();
+ if (safe_point >= start) break;
+ first_safe_point_index++;
+ }
+
+ // Step through the safe points to see whether they are in the range.
+ for (int safe_point_index = first_safe_point_index;
+ safe_point_index < pointer_maps->length();
+ ++safe_point_index) {
+ LPointerMap* map = pointer_maps->at(safe_point_index);
+ int safe_point = map->lithium_position();
+
+ // The safe points are sorted so we can stop searching here.
+ if (safe_point - 1 > end) break;
+
+ // Advance to the next active range that covers the current
+ // safe point position.
+ LifetimePosition safe_point_pos =
+ LifetimePosition::FromInstructionIndex(safe_point);
+ LiveRange* cur = range;
+ while (cur != NULL && !cur->Covers(safe_point_pos)) {
+ cur = cur->next();
+ }
+ if (cur == NULL) continue;
+
+ // Check if the live range is spilled and the safe point is after
+ // the spill position.
+ if (range->HasAllocatedSpillOperand() &&
+ safe_point >= range->spill_start_index()) {
+ TraceAlloc("Pointer for range %d (spilled at %d) at safe point %d\n",
+ range->id(), range->spill_start_index(), safe_point);
+ map->RecordPointer(range->GetSpillOperand(), chunk()->zone());
+ }
+
+ if (!cur->IsSpilled()) {
+ TraceAlloc("Pointer in register for range %d (start at %d) "
+ "at safe point %d\n",
+ cur->id(), cur->Start().Value(), safe_point);
+ LOperand* operand = cur->CreateAssignedOperand(chunk()->zone());
+ DCHECK(!operand->IsStackSlot());
+ map->RecordPointer(operand, chunk()->zone());
+ }
+ }
+ }
+}
+
+
+void LAllocator::AllocateGeneralRegisters() {
+ LAllocatorPhase phase("L_Allocate general registers", this);
+ num_registers_ =
+ RegisterConfiguration::ArchDefault(RegisterConfiguration::CRANKSHAFT)
+ ->num_allocatable_general_registers();
+ allocatable_register_codes_ =
+ RegisterConfiguration::ArchDefault(RegisterConfiguration::CRANKSHAFT)
+ ->allocatable_general_codes();
+ mode_ = GENERAL_REGISTERS;
+ AllocateRegisters();
+}
+
+
+void LAllocator::AllocateDoubleRegisters() {
+ LAllocatorPhase phase("L_Allocate double registers", this);
+ num_registers_ =
+ RegisterConfiguration::ArchDefault(RegisterConfiguration::CRANKSHAFT)
+ ->num_allocatable_double_registers();
+ allocatable_register_codes_ =
+ RegisterConfiguration::ArchDefault(RegisterConfiguration::CRANKSHAFT)
+ ->allocatable_double_codes();
+ mode_ = DOUBLE_REGISTERS;
+ AllocateRegisters();
+}
+
+
+void LAllocator::AllocateRegisters() {
+ DCHECK(unhandled_live_ranges_.is_empty());
+
+ for (int i = 0; i < live_ranges_.length(); ++i) {
+ if (live_ranges_[i] != NULL) {
+ if (live_ranges_[i]->Kind() == mode_) {
+ AddToUnhandledUnsorted(live_ranges_[i]);
+ }
+ }
+ }
+ SortUnhandled();
+ DCHECK(UnhandledIsSorted());
+
+ DCHECK(reusable_slots_.is_empty());
+ DCHECK(active_live_ranges_.is_empty());
+ DCHECK(inactive_live_ranges_.is_empty());
+
+ if (mode_ == DOUBLE_REGISTERS) {
+ for (int i = 0; i < fixed_double_live_ranges_.length(); ++i) {
+ LiveRange* current = fixed_double_live_ranges_.at(i);
+ if (current != NULL) {
+ AddToInactive(current);
+ }
+ }
+ } else {
+ DCHECK(mode_ == GENERAL_REGISTERS);
+ for (int i = 0; i < fixed_live_ranges_.length(); ++i) {
+ LiveRange* current = fixed_live_ranges_.at(i);
+ if (current != NULL) {
+ AddToInactive(current);
+ }
+ }
+ }
+
+ while (!unhandled_live_ranges_.is_empty()) {
+ DCHECK(UnhandledIsSorted());
+ LiveRange* current = unhandled_live_ranges_.RemoveLast();
+ DCHECK(UnhandledIsSorted());
+ LifetimePosition position = current->Start();
+#ifdef DEBUG
+ allocation_finger_ = position;
+#endif
+ TraceAlloc("Processing interval %d start=%d\n",
+ current->id(),
+ position.Value());
+
+ if (current->HasAllocatedSpillOperand()) {
+ TraceAlloc("Live range %d already has a spill operand\n", current->id());
+ LifetimePosition next_pos = position;
+ if (IsGapAt(next_pos.InstructionIndex())) {
+ next_pos = next_pos.NextInstruction();
+ }
+ UsePosition* pos = current->NextUsePositionRegisterIsBeneficial(next_pos);
+ // If the range already has a spill operand and it doesn't need a
+ // register immediately, split it and spill the first part of the range.
+ if (pos == NULL) {
+ Spill(current);
+ continue;
+ } else if (pos->pos().Value() >
+ current->Start().NextInstruction().Value()) {
+ // Do not spill live range eagerly if use position that can benefit from
+ // the register is too close to the start of live range.
+ SpillBetween(current, current->Start(), pos->pos());
+ if (!AllocationOk()) return;
+ DCHECK(UnhandledIsSorted());
+ continue;
+ }
+ }
+
+ for (int i = 0; i < active_live_ranges_.length(); ++i) {
+ LiveRange* cur_active = active_live_ranges_.at(i);
+ if (cur_active->End().Value() <= position.Value()) {
+ ActiveToHandled(cur_active);
+ --i; // The live range was removed from the list of active live ranges.
+ } else if (!cur_active->Covers(position)) {
+ ActiveToInactive(cur_active);
+ --i; // The live range was removed from the list of active live ranges.
+ }
+ }
+
+ for (int i = 0; i < inactive_live_ranges_.length(); ++i) {
+ LiveRange* cur_inactive = inactive_live_ranges_.at(i);
+ if (cur_inactive->End().Value() <= position.Value()) {
+ InactiveToHandled(cur_inactive);
+ --i; // Live range was removed from the list of inactive live ranges.
+ } else if (cur_inactive->Covers(position)) {
+ InactiveToActive(cur_inactive);
+ --i; // Live range was removed from the list of inactive live ranges.
+ }
+ }
+
+ DCHECK(!current->HasRegisterAssigned() && !current->IsSpilled());
+
+ bool result = TryAllocateFreeReg(current);
+ if (!AllocationOk()) return;
+
+ if (!result) AllocateBlockedReg(current);
+ if (!AllocationOk()) return;
+
+ if (current->HasRegisterAssigned()) {
+ AddToActive(current);
+ }
+ }
+
+ reusable_slots_.Rewind(0);
+ active_live_ranges_.Rewind(0);
+ inactive_live_ranges_.Rewind(0);
+}
+
+
+const char* LAllocator::RegisterName(int allocation_index) {
+ if (mode_ == GENERAL_REGISTERS) {
+ return Register::from_code(allocation_index).ToString();
+ } else {
+ return DoubleRegister::from_code(allocation_index).ToString();
+ }
+}
+
+
+void LAllocator::TraceAlloc(const char* msg, ...) {
+ if (FLAG_trace_alloc) {
+ va_list arguments;
+ va_start(arguments, msg);
+ base::OS::VPrint(msg, arguments);
+ va_end(arguments);
+ }
+}
+
+
+bool LAllocator::HasTaggedValue(int virtual_register) const {
+ HValue* value = graph_->LookupValue(virtual_register);
+ if (value == NULL) return false;
+ return value->representation().IsTagged() && !value->type().IsSmi();
+}
+
+
+RegisterKind LAllocator::RequiredRegisterKind(int virtual_register) const {
+ if (virtual_register < first_artificial_register_) {
+ HValue* value = graph_->LookupValue(virtual_register);
+ if (value != NULL && value->representation().IsDouble()) {
+ return DOUBLE_REGISTERS;
+ }
+ } else if (double_artificial_registers_.Contains(
+ virtual_register - first_artificial_register_)) {
+ return DOUBLE_REGISTERS;
+ }
+
+ return GENERAL_REGISTERS;
+}
+
+
+void LAllocator::AddToActive(LiveRange* range) {
+ TraceAlloc("Add live range %d to active\n", range->id());
+ active_live_ranges_.Add(range, zone());
+}
+
+
+void LAllocator::AddToInactive(LiveRange* range) {
+ TraceAlloc("Add live range %d to inactive\n", range->id());
+ inactive_live_ranges_.Add(range, zone());
+}
+
+
+void LAllocator::AddToUnhandledSorted(LiveRange* range) {
+ if (range == NULL || range->IsEmpty()) return;
+ DCHECK(!range->HasRegisterAssigned() && !range->IsSpilled());
+ DCHECK(allocation_finger_.Value() <= range->Start().Value());
+ for (int i = unhandled_live_ranges_.length() - 1; i >= 0; --i) {
+ LiveRange* cur_range = unhandled_live_ranges_.at(i);
+ if (range->ShouldBeAllocatedBefore(cur_range)) {
+ TraceAlloc("Add live range %d to unhandled at %d\n", range->id(), i + 1);
+ unhandled_live_ranges_.InsertAt(i + 1, range, zone());
+ DCHECK(UnhandledIsSorted());
+ return;
+ }
+ }
+ TraceAlloc("Add live range %d to unhandled at start\n", range->id());
+ unhandled_live_ranges_.InsertAt(0, range, zone());
+ DCHECK(UnhandledIsSorted());
+}
+
+
+void LAllocator::AddToUnhandledUnsorted(LiveRange* range) {
+ if (range == NULL || range->IsEmpty()) return;
+ DCHECK(!range->HasRegisterAssigned() && !range->IsSpilled());
+ TraceAlloc("Add live range %d to unhandled unsorted at end\n", range->id());
+ unhandled_live_ranges_.Add(range, zone());
+}
+
+
+static int UnhandledSortHelper(LiveRange* const* a, LiveRange* const* b) {
+ DCHECK(!(*a)->ShouldBeAllocatedBefore(*b) ||
+ !(*b)->ShouldBeAllocatedBefore(*a));
+ if ((*a)->ShouldBeAllocatedBefore(*b)) return 1;
+ if ((*b)->ShouldBeAllocatedBefore(*a)) return -1;
+ return (*a)->id() - (*b)->id();
+}
+
+
+// Sort the unhandled live ranges so that the ranges to be processed first are
+// at the end of the array list. This is convenient for the register allocation
+// algorithm because it is efficient to remove elements from the end.
+void LAllocator::SortUnhandled() {
+ TraceAlloc("Sort unhandled\n");
+ unhandled_live_ranges_.Sort(&UnhandledSortHelper);
+}
+
+
+bool LAllocator::UnhandledIsSorted() {
+ int len = unhandled_live_ranges_.length();
+ for (int i = 1; i < len; i++) {
+ LiveRange* a = unhandled_live_ranges_.at(i - 1);
+ LiveRange* b = unhandled_live_ranges_.at(i);
+ if (a->Start().Value() < b->Start().Value()) return false;
+ }
+ return true;
+}
+
+
+void LAllocator::FreeSpillSlot(LiveRange* range) {
+ // Check that we are the last range.
+ if (range->next() != NULL) return;
+
+ if (!range->TopLevel()->HasAllocatedSpillOperand()) return;
+
+ int index = range->TopLevel()->GetSpillOperand()->index();
+ if (index >= 0) {
+ reusable_slots_.Add(range, zone());
+ }
+}
+
+
+LOperand* LAllocator::TryReuseSpillSlot(LiveRange* range) {
+ if (reusable_slots_.is_empty()) return NULL;
+ if (reusable_slots_.first()->End().Value() >
+ range->TopLevel()->Start().Value()) {
+ return NULL;
+ }
+ LOperand* result = reusable_slots_.first()->TopLevel()->GetSpillOperand();
+ reusable_slots_.Remove(0);
+ return result;
+}
+
+
+void LAllocator::ActiveToHandled(LiveRange* range) {
+ DCHECK(active_live_ranges_.Contains(range));
+ active_live_ranges_.RemoveElement(range);
+ TraceAlloc("Moving live range %d from active to handled\n", range->id());
+ FreeSpillSlot(range);
+}
+
+
+void LAllocator::ActiveToInactive(LiveRange* range) {
+ DCHECK(active_live_ranges_.Contains(range));
+ active_live_ranges_.RemoveElement(range);
+ inactive_live_ranges_.Add(range, zone());
+ TraceAlloc("Moving live range %d from active to inactive\n", range->id());
+}
+
+
+void LAllocator::InactiveToHandled(LiveRange* range) {
+ DCHECK(inactive_live_ranges_.Contains(range));
+ inactive_live_ranges_.RemoveElement(range);
+ TraceAlloc("Moving live range %d from inactive to handled\n", range->id());
+ FreeSpillSlot(range);
+}
+
+
+void LAllocator::InactiveToActive(LiveRange* range) {
+ DCHECK(inactive_live_ranges_.Contains(range));
+ inactive_live_ranges_.RemoveElement(range);
+ active_live_ranges_.Add(range, zone());
+ TraceAlloc("Moving live range %d from inactive to active\n", range->id());
+}
+
+
+bool LAllocator::TryAllocateFreeReg(LiveRange* current) {
+ DCHECK(DoubleRegister::kMaxNumRegisters >= Register::kNumRegisters);
+
+ LifetimePosition free_until_pos[DoubleRegister::kMaxNumRegisters];
+
+ for (int i = 0; i < DoubleRegister::kMaxNumRegisters; i++) {
+ free_until_pos[i] = LifetimePosition::MaxPosition();
+ }
+
+ for (int i = 0; i < active_live_ranges_.length(); ++i) {
+ LiveRange* cur_active = active_live_ranges_.at(i);
+ free_until_pos[cur_active->assigned_register()] =
+ LifetimePosition::FromInstructionIndex(0);
+ }
+
+ for (int i = 0; i < inactive_live_ranges_.length(); ++i) {
+ LiveRange* cur_inactive = inactive_live_ranges_.at(i);
+ DCHECK(cur_inactive->End().Value() > current->Start().Value());
+ LifetimePosition next_intersection =
+ cur_inactive->FirstIntersection(current);
+ if (!next_intersection.IsValid()) continue;
+ int cur_reg = cur_inactive->assigned_register();
+ free_until_pos[cur_reg] = Min(free_until_pos[cur_reg], next_intersection);
+ }
+
+ LOperand* hint = current->FirstHint();
+ if (hint != NULL && (hint->IsRegister() || hint->IsDoubleRegister())) {
+ int register_index = hint->index();
+ TraceAlloc(
+ "Found reg hint %s (free until [%d) for live range %d (end %d[).\n",
+ RegisterName(register_index),
+ free_until_pos[register_index].Value(),
+ current->id(),
+ current->End().Value());
+
+ // The desired register is free until the end of the current live range.
+ if (free_until_pos[register_index].Value() >= current->End().Value()) {
+ TraceAlloc("Assigning preferred reg %s to live range %d\n",
+ RegisterName(register_index),
+ current->id());
+ SetLiveRangeAssignedRegister(current, register_index);
+ return true;
+ }
+ }
+
+ // Find the register which stays free for the longest time.
+ int reg = allocatable_register_codes_[0];
+ for (int i = 1; i < RegisterCount(); ++i) {
+ int code = allocatable_register_codes_[i];
+ if (free_until_pos[code].Value() > free_until_pos[reg].Value()) {
+ reg = code;
+ }
+ }
+
+ LifetimePosition pos = free_until_pos[reg];
+
+ if (pos.Value() <= current->Start().Value()) {
+ // All registers are blocked.
+ return false;
+ }
+
+ if (pos.Value() < current->End().Value()) {
+ // Register reg is available at the range start but becomes blocked before
+ // the range end. Split current at position where it becomes blocked.
+ LiveRange* tail = SplitRangeAt(current, pos);
+ if (!AllocationOk()) return false;
+ AddToUnhandledSorted(tail);
+ }
+
+
+ // Register reg is available at the range start and is free until
+ // the range end.
+ DCHECK(pos.Value() >= current->End().Value());
+ TraceAlloc("Assigning free reg %s to live range %d\n",
+ RegisterName(reg),
+ current->id());
+ SetLiveRangeAssignedRegister(current, reg);
+
+ return true;
+}
+
+
+void LAllocator::AllocateBlockedReg(LiveRange* current) {
+ UsePosition* register_use = current->NextRegisterPosition(current->Start());
+ if (register_use == NULL) {
+ // There is no use in the current live range that requires a register.
+ // We can just spill it.
+ Spill(current);
+ return;
+ }
+
+
+ LifetimePosition use_pos[DoubleRegister::kMaxNumRegisters];
+ LifetimePosition block_pos[DoubleRegister::kMaxNumRegisters];
+
+ for (int i = 0; i < DoubleRegister::kMaxNumRegisters; i++) {
+ use_pos[i] = block_pos[i] = LifetimePosition::MaxPosition();
+ }
+
+ for (int i = 0; i < active_live_ranges_.length(); ++i) {
+ LiveRange* range = active_live_ranges_[i];
+ int cur_reg = range->assigned_register();
+ if (range->IsFixed() || !range->CanBeSpilled(current->Start())) {
+ block_pos[cur_reg] = use_pos[cur_reg] =
+ LifetimePosition::FromInstructionIndex(0);
+ } else {
+ UsePosition* next_use = range->NextUsePositionRegisterIsBeneficial(
+ current->Start());
+ if (next_use == NULL) {
+ use_pos[cur_reg] = range->End();
+ } else {
+ use_pos[cur_reg] = next_use->pos();
+ }
+ }
+ }
+
+ for (int i = 0; i < inactive_live_ranges_.length(); ++i) {
+ LiveRange* range = inactive_live_ranges_.at(i);
+ DCHECK(range->End().Value() > current->Start().Value());
+ LifetimePosition next_intersection = range->FirstIntersection(current);
+ if (!next_intersection.IsValid()) continue;
+ int cur_reg = range->assigned_register();
+ if (range->IsFixed()) {
+ block_pos[cur_reg] = Min(block_pos[cur_reg], next_intersection);
+ use_pos[cur_reg] = Min(block_pos[cur_reg], use_pos[cur_reg]);
+ } else {
+ use_pos[cur_reg] = Min(use_pos[cur_reg], next_intersection);
+ }
+ }
+
+ int reg = allocatable_register_codes_[0];
+ for (int i = 1; i < RegisterCount(); ++i) {
+ int code = allocatable_register_codes_[i];
+ if (use_pos[code].Value() > use_pos[reg].Value()) {
+ reg = code;
+ }
+ }
+
+ LifetimePosition pos = use_pos[reg];
+
+ if (pos.Value() < register_use->pos().Value()) {
+ // All registers are blocked before the first use that requires a register.
+ // Spill starting part of live range up to that use.
+ SpillBetween(current, current->Start(), register_use->pos());
+ return;
+ }
+
+ if (block_pos[reg].Value() < current->End().Value()) {
+ // Register becomes blocked before the current range end. Split before that
+ // position.
+ LiveRange* tail = SplitBetween(current,
+ current->Start(),
+ block_pos[reg].InstructionStart());
+ if (!AllocationOk()) return;
+ AddToUnhandledSorted(tail);
+ }
+
+ // Register reg is not blocked for the whole range.
+ DCHECK(block_pos[reg].Value() >= current->End().Value());
+ TraceAlloc("Assigning blocked reg %s to live range %d\n",
+ RegisterName(reg),
+ current->id());
+ SetLiveRangeAssignedRegister(current, reg);
+
+ // This register was not free. Thus we need to find and spill
+ // parts of active and inactive live regions that use the same register
+ // at the same lifetime positions as current.
+ SplitAndSpillIntersecting(current);
+}
+
+
+LifetimePosition LAllocator::FindOptimalSpillingPos(LiveRange* range,
+ LifetimePosition pos) {
+ HBasicBlock* block = GetBlock(pos.InstructionStart());
+ HBasicBlock* loop_header =
+ block->IsLoopHeader() ? block : block->parent_loop_header();
+
+ if (loop_header == NULL) return pos;
+
+ UsePosition* prev_use =
+ range->PreviousUsePositionRegisterIsBeneficial(pos);
+
+ while (loop_header != NULL) {
+ // We are going to spill live range inside the loop.
+ // If possible try to move spilling position backwards to loop header.
+ // This will reduce number of memory moves on the back edge.
+ LifetimePosition loop_start = LifetimePosition::FromInstructionIndex(
+ loop_header->first_instruction_index());
+
+ if (range->Covers(loop_start)) {
+ if (prev_use == NULL || prev_use->pos().Value() < loop_start.Value()) {
+ // No register beneficial use inside the loop before the pos.
+ pos = loop_start;
+ }
+ }
+
+ // Try hoisting out to an outer loop.
+ loop_header = loop_header->parent_loop_header();
+ }
+
+ return pos;
+}
+
+
+void LAllocator::SplitAndSpillIntersecting(LiveRange* current) {
+ DCHECK(current->HasRegisterAssigned());
+ int reg = current->assigned_register();
+ LifetimePosition split_pos = current->Start();
+ for (int i = 0; i < active_live_ranges_.length(); ++i) {
+ LiveRange* range = active_live_ranges_[i];
+ if (range->assigned_register() == reg) {
+ UsePosition* next_pos = range->NextRegisterPosition(current->Start());
+ LifetimePosition spill_pos = FindOptimalSpillingPos(range, split_pos);
+ if (next_pos == NULL) {
+ SpillAfter(range, spill_pos);
+ } else {
+ // When spilling between spill_pos and next_pos ensure that the range
+ // remains spilled at least until the start of the current live range.
+ // This guarantees that we will not introduce new unhandled ranges that
+ // start before the current range as this violates allocation invariant
+ // and will lead to an inconsistent state of active and inactive
+ // live-ranges: ranges are allocated in order of their start positions,
+ // ranges are retired from active/inactive when the start of the
+ // current live-range is larger than their end.
+ SpillBetweenUntil(range, spill_pos, current->Start(), next_pos->pos());
+ }
+ if (!AllocationOk()) return;
+ ActiveToHandled(range);
+ --i;
+ }
+ }
+
+ for (int i = 0; i < inactive_live_ranges_.length(); ++i) {
+ LiveRange* range = inactive_live_ranges_[i];
+ DCHECK(range->End().Value() > current->Start().Value());
+ if (range->assigned_register() == reg && !range->IsFixed()) {
+ LifetimePosition next_intersection = range->FirstIntersection(current);
+ if (next_intersection.IsValid()) {
+ UsePosition* next_pos = range->NextRegisterPosition(current->Start());
+ if (next_pos == NULL) {
+ SpillAfter(range, split_pos);
+ } else {
+ next_intersection = Min(next_intersection, next_pos->pos());
+ SpillBetween(range, split_pos, next_intersection);
+ }
+ if (!AllocationOk()) return;
+ InactiveToHandled(range);
+ --i;
+ }
+ }
+ }
+}
+
+
+bool LAllocator::IsBlockBoundary(LifetimePosition pos) {
+ return pos.IsInstructionStart() &&
+ InstructionAt(pos.InstructionIndex())->IsLabel();
+}
+
+
+LiveRange* LAllocator::SplitRangeAt(LiveRange* range, LifetimePosition pos) {
+ DCHECK(!range->IsFixed());
+ TraceAlloc("Splitting live range %d at %d\n", range->id(), pos.Value());
+
+ if (pos.Value() <= range->Start().Value()) return range;
+
+ // We can't properly connect liveranges if split occured at the end
+ // of control instruction.
+ DCHECK(pos.IsInstructionStart() ||
+ !chunk_->instructions()->at(pos.InstructionIndex())->IsControl());
+
+ int vreg = GetVirtualRegister();
+ if (!AllocationOk()) return NULL;
+ LiveRange* result = LiveRangeFor(vreg);
+ range->SplitAt(pos, result, zone());
+ return result;
+}
+
+
+LiveRange* LAllocator::SplitBetween(LiveRange* range,
+ LifetimePosition start,
+ LifetimePosition end) {
+ DCHECK(!range->IsFixed());
+ TraceAlloc("Splitting live range %d in position between [%d, %d]\n",
+ range->id(),
+ start.Value(),
+ end.Value());
+
+ LifetimePosition split_pos = FindOptimalSplitPos(start, end);
+ DCHECK(split_pos.Value() >= start.Value());
+ return SplitRangeAt(range, split_pos);
+}
+
+
+LifetimePosition LAllocator::FindOptimalSplitPos(LifetimePosition start,
+ LifetimePosition end) {
+ int start_instr = start.InstructionIndex();
+ int end_instr = end.InstructionIndex();
+ DCHECK(start_instr <= end_instr);
+
+ // We have no choice
+ if (start_instr == end_instr) return end;
+
+ HBasicBlock* start_block = GetBlock(start);
+ HBasicBlock* end_block = GetBlock(end);
+
+ if (end_block == start_block) {
+ // The interval is split in the same basic block. Split at the latest
+ // possible position.
+ return end;
+ }
+
+ HBasicBlock* block = end_block;
+ // Find header of outermost loop.
+ while (block->parent_loop_header() != NULL &&
+ block->parent_loop_header()->block_id() > start_block->block_id()) {
+ block = block->parent_loop_header();
+ }
+
+ // We did not find any suitable outer loop. Split at the latest possible
+ // position unless end_block is a loop header itself.
+ if (block == end_block && !end_block->IsLoopHeader()) return end;
+
+ return LifetimePosition::FromInstructionIndex(
+ block->first_instruction_index());
+}
+
+
+void LAllocator::SpillAfter(LiveRange* range, LifetimePosition pos) {
+ LiveRange* second_part = SplitRangeAt(range, pos);
+ if (!AllocationOk()) return;
+ Spill(second_part);
+}
+
+
+void LAllocator::SpillBetween(LiveRange* range,
+ LifetimePosition start,
+ LifetimePosition end) {
+ SpillBetweenUntil(range, start, start, end);
+}
+
+
+void LAllocator::SpillBetweenUntil(LiveRange* range,
+ LifetimePosition start,
+ LifetimePosition until,
+ LifetimePosition end) {
+ CHECK(start.Value() < end.Value());
+ LiveRange* second_part = SplitRangeAt(range, start);
+ if (!AllocationOk()) return;
+
+ if (second_part->Start().Value() < end.Value()) {
+ // The split result intersects with [start, end[.
+ // Split it at position between ]start+1, end[, spill the middle part
+ // and put the rest to unhandled.
+ LiveRange* third_part = SplitBetween(
+ second_part,
+ Max(second_part->Start().InstructionEnd(), until),
+ end.PrevInstruction().InstructionEnd());
+ if (!AllocationOk()) return;
+
+ DCHECK(third_part != second_part);
+
+ Spill(second_part);
+ AddToUnhandledSorted(third_part);
+ } else {
+ // The split result does not intersect with [start, end[.
+ // Nothing to spill. Just put it to unhandled as whole.
+ AddToUnhandledSorted(second_part);
+ }
+}
+
+
+void LAllocator::Spill(LiveRange* range) {
+ DCHECK(!range->IsSpilled());
+ TraceAlloc("Spilling live range %d\n", range->id());
+ LiveRange* first = range->TopLevel();
+
+ if (!first->HasAllocatedSpillOperand()) {
+ LOperand* op = TryReuseSpillSlot(range);
+ if (op == NULL) op = chunk_->GetNextSpillSlot(range->Kind());
+ first->SetSpillOperand(op);
+ }
+ range->MakeSpilled(chunk()->zone());
+}
+
+
+int LAllocator::RegisterCount() const {
+ return num_registers_;
+}
+
+
+#ifdef DEBUG
+
+
+void LAllocator::Verify() const {
+ for (int i = 0; i < live_ranges()->length(); ++i) {
+ LiveRange* current = live_ranges()->at(i);
+ if (current != NULL) current->Verify();
+ }
+}
+
+
+#endif
+
+
+LAllocatorPhase::LAllocatorPhase(const char* name, LAllocator* allocator)
+ : CompilationPhase(name, allocator->graph()->info()),
+ allocator_(allocator) {
+ if (FLAG_hydrogen_stats) {
+ allocator_zone_start_allocation_size_ =
+ allocator->zone()->allocation_size();
+ }
+}
+
+
+LAllocatorPhase::~LAllocatorPhase() {
+ if (FLAG_hydrogen_stats) {
+ size_t size = allocator_->zone()->allocation_size() -
+ allocator_zone_start_allocation_size_;
+ isolate()->GetHStatistics()->SaveTiming(name(), base::TimeDelta(), size);
+ }
+
+ if (ShouldProduceTraceOutput()) {
+ isolate()->GetHTracer()->TraceLithium(name(), allocator_->chunk());
+ isolate()->GetHTracer()->TraceLiveRanges(name(), allocator_);
+ }
+
+#ifdef DEBUG
+ if (allocator_ != NULL) allocator_->Verify();
+#endif
+}
+
+
+} // namespace internal
+} // namespace v8