Land the Fan (disabled)

src/compiler/register-allocator.cc

-// Copyright 2012 the V8 project authors. All rights reserved.
+// Copyright 2014 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/v8.h"
+#include "src/compiler/register-allocator.h"
 
+#include "src/compiler/linkage.h"
 #include "src/hydrogen.h"
-#include "src/lithium-allocator-inl.h"
 #include "src/string-stream.h"
 
-#if V8_TARGET_ARCH_IA32
-#include "src/ia32/lithium-ia32.h"  // NOLINT
-#elif V8_TARGET_ARCH_X64
-#include "src/x64/lithium-x64.h"  // NOLINT
-#elif V8_TARGET_ARCH_ARM64
-#include "src/arm64/lithium-arm64.h"  // NOLINT
-#elif V8_TARGET_ARCH_ARM
-#include "src/arm/lithium-arm.h"  // NOLINT
-#elif V8_TARGET_ARCH_MIPS
-#include "src/mips/lithium-mips.h"  // NOLINT
-#elif V8_TARGET_ARCH_MIPS64
-#include "src/mips64/lithium-mips64.h"  // NOLINT
-#elif V8_TARGET_ARCH_X87
-#include "src/x87/lithium-x87.h"  // NOLINT
-#else
-#error "Unknown architecture."
-#endif
-
 namespace v8 {
 namespace internal {
+namespace compiler {
 
 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)
+UsePosition::UsePosition(LifetimePosition pos, InstructionOperand* operand,
+                         InstructionOperand* 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();
+    const UnallocatedOperand* unalloc = UnallocatedOperand::cast(operand_);
+    requires_reg_ = unalloc->HasRegisterPolicy();
     register_beneficial_ = !unalloc->HasAnyPolicy();
   }
   ASSERT(pos_.IsValid());
 }
 
 
 bool UsePosition::HasHint() const {
   return hint_ != NULL && !hint_->IsUnallocated();
 }
 
@@ skipping 43 matching lines @@
   return false;
 }
 
 
 #endif
 
 
 LiveRange::LiveRange(int id, Zone* zone)
     : id_(id),
       spilled_(false),
+      is_phi_(false),
+      is_non_loop_phi_(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) { }
+      spill_operand_(new (zone) InstructionOperand()),
+      spill_start_index_(kMaxInt) {}
 
 
 void LiveRange::set_assigned_register(int reg, Zone* zone) {
   ASSERT(!HasRegisterAssigned() && !IsSpilled());
   assigned_register_ = reg;
   ConvertOperands(zone);
 }
 
 
 void LiveRange::MakeSpilled(Zone* zone) {
   ASSERT(!IsSpilled());
   ASSERT(TopLevel()->HasAllocatedSpillOperand());
   spilled_ = true;
   assigned_register_ = kInvalidAssignment;
   ConvertOperands(zone);
 }
 
 
 bool LiveRange::HasAllocatedSpillOperand() const {
   ASSERT(spill_operand_ != NULL);
   return !spill_operand_->IsIgnored();
 }
 
 
-void LiveRange::SetSpillOperand(LOperand* operand) {
+void LiveRange::SetSpillOperand(InstructionOperand* operand) {
   ASSERT(!operand->IsUnallocated());
   ASSERT(spill_operand_ != NULL);
   ASSERT(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();
@@ skipping 39 matching lines @@
 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;
+InstructionOperand* LiveRange::CreateAssignedOperand(Zone* zone) {
+  InstructionOperand* op = NULL;
   if (HasRegisterAssigned()) {
     ASSERT(!IsSpilled());
     switch (Kind()) {
       case GENERAL_REGISTERS:
-        op = LRegister::Create(assigned_register(), zone);
+        op = RegisterOperand::Create(assigned_register(), zone);
         break;
       case DOUBLE_REGISTERS:
-        op = LDoubleRegister::Create(assigned_register(), zone);
+        op = DoubleRegisterOperand::Create(assigned_register(), zone);
         break;
       default:
         UNREACHABLE();
     }
   } else if (IsSpilled()) {
     ASSERT(!HasRegisterAssigned());
     op = TopLevel()->GetSpillOperand();
     ASSERT(!op->IsUnallocated());
   } else {
-    LUnallocated* unalloc = new(zone) LUnallocated(LUnallocated::NONE);
+    UnallocatedOperand* unalloc =
+        new (zone) UnallocatedOperand(UnallocatedOperand::NONE);
     unalloc->set_virtual_register(id_);
     op = unalloc;
   }
   return op;
 }
 
 
 UseInterval* LiveRange::FirstSearchIntervalForPosition(
     LifetimePosition position) const {
   if (current_interval_ == NULL) return first_interval_;
@@ skipping 118 matching lines @@
     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());
+  RegisterAllocator::TraceAlloc("Shorten live range %d to [%d\n",
+                                id_, start.Value());
   ASSERT(first_interval_ != NULL);
   ASSERT(first_interval_->start().Value() <= start.Value());
   ASSERT(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());
+  RegisterAllocator::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());
+  RegisterAllocator::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.
       ASSERT(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());
+                               InstructionOperand* operand,
+                               InstructionOperand* hint, Zone* zone) {
+  RegisterAllocator::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);
+  InstructionOperand* op = CreateAssignedOperand(zone);
   UsePosition* use_pos = first_pos();
   while (use_pos != NULL) {
     ASSERT(Start().Value() <= use_pos->pos().Value() &&
            use_pos->pos().Value() <= End().Value());
 
     if (use_pos->HasOperand()) {
       ASSERT(op->IsRegister() || op->IsDoubleRegister() ||
              !use_pos->RequiresRegister());
       use_pos->operand()->ConvertTo(op->kind(), op->index());
     }
@@ skipping 42 matching lines @@
       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)
-    : zone_(graph->isolate()),
-      chunk_(NULL),
-      live_in_sets_(graph->blocks()->length(), zone()),
-      live_ranges_(num_values * 2, zone()),
+RegisterAllocator::RegisterAllocator(InstructionSequence* code)
+    : zone_(code->isolate()),
+      code_(code),
+      live_in_sets_(code->BasicBlockCount(), zone()),
+      live_ranges_(code->VirtualRegisterCount() * 2, zone()),
       fixed_live_ranges_(NULL),
       fixed_double_live_ranges_(NULL),
-      unhandled_live_ranges_(num_values * 2, zone()),
+      unhandled_live_ranges_(code->VirtualRegisterCount() * 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) { }
+      allocation_ok_(true) {}
 
 
-void LAllocator::InitializeLivenessAnalysis() {
+void RegisterAllocator::InitializeLivenessAnalysis() {
   // Initialize the live_in sets for each block to NULL.
-  int block_count = graph_->blocks()->length();
+  int block_count = code()->BasicBlockCount();
   live_in_sets_.Initialize(block_count, zone());
   live_in_sets_.AddBlock(NULL, block_count, zone());
 }
 
 
-BitVector* LAllocator::ComputeLiveOut(HBasicBlock* block) {
+BitVector* RegisterAllocator::ComputeLiveOut(BasicBlock* block) {
   // Compute live out for the given block, except not including backward
   // successor edges.
-  BitVector* live_out = new(zone()) BitVector(next_virtual_register_, zone());
+  BitVector* live_out =
+      new (zone()) BitVector(code()->VirtualRegisterCount(), zone());
 
   // Process all successor blocks.
-  for (HSuccessorIterator it(block->end()); !it.Done(); it.Advance()) {
+  BasicBlock::Successors successors = block->successors();
+  for (BasicBlock::Successors::iterator i = successors.begin();
+       i != successors.end(); ++i) {
     // 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()];
+    BasicBlock* successor = *i;
+    BitVector* live_in = live_in_sets_[successor->rpo_number_];
     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());
-      }
+    ASSERT(index >= 0);
+    ASSERT(index < static_cast<int>(successor->PredecessorCount()));
+    for (BasicBlock::const_iterator j = successor->begin();
+         j != successor->end(); ++j) {
+      Node* phi = *j;
+      if (phi->opcode() != IrOpcode::kPhi) continue;
+      Node* input = phi->InputAt(index);
+      live_out->Add(input->id());
     }
   }
 
   return live_out;
 }
 
 
-void LAllocator::AddInitialIntervals(HBasicBlock* block,
-                                     BitVector* live_out) {
+void RegisterAllocator::AddInitialIntervals(BasicBlock* 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) {
+int RegisterAllocator::FixedDoubleLiveRangeID(int index) {
   return -index - 1 - Register::kMaxNumAllocatableRegisters;
 }
 
 
-LOperand* LAllocator::AllocateFixed(LUnallocated* operand,
-                                    int pos,
-                                    bool is_tagged) {
+InstructionOperand* RegisterAllocator::AllocateFixed(
+    UnallocatedOperand* operand, int pos, bool is_tagged) {
   TraceAlloc("Allocating fixed reg for op %d\n", operand->virtual_register());
   ASSERT(operand->HasFixedPolicy());
   if (operand->HasFixedSlotPolicy()) {
-    operand->ConvertTo(LOperand::STACK_SLOT, operand->fixed_slot_index());
+    operand->ConvertTo(InstructionOperand::STACK_SLOT,
+                       operand->fixed_slot_index());
   } else if (operand->HasFixedRegisterPolicy()) {
     int reg_index = operand->fixed_register_index();
-    operand->ConvertTo(LOperand::REGISTER, reg_index);
+    operand->ConvertTo(InstructionOperand::REGISTER, reg_index);
   } else if (operand->HasFixedDoubleRegisterPolicy()) {
     int reg_index = operand->fixed_register_index();
-    operand->ConvertTo(LOperand::DOUBLE_REGISTER, reg_index);
+    operand->ConvertTo(InstructionOperand::DOUBLE_REGISTER, reg_index);
   } else {
     UNREACHABLE();
   }
   if (is_tagged) {
     TraceAlloc("Fixed reg is tagged at %d\n", pos);
-    LInstruction* instr = InstructionAt(pos);
+    Instruction* instr = InstructionAt(pos);
     if (instr->HasPointerMap()) {
-      instr->pointer_map()->RecordPointer(operand, chunk()->zone());
+      instr->pointer_map()->RecordPointer(operand, code_zone());
     }
   }
   return operand;
 }
 
 
-LiveRange* LAllocator::FixedLiveRangeFor(int index) {
+LiveRange* RegisterAllocator::FixedLiveRangeFor(int index) {
   ASSERT(index < Register::kMaxNumAllocatableRegisters);
   LiveRange* result = fixed_live_ranges_[index];
   if (result == NULL) {
-    result = new(zone()) LiveRange(FixedLiveRangeID(index), chunk()->zone());
+    // TODO(titzer): add a utility method to allocate a new LiveRange:
+    // The LiveRange object itself can go in this zone, but the
+    // InstructionOperand needs
+    // to go in the code zone, since it may survive register allocation.
+    result = new(zone()) LiveRange(FixedLiveRangeID(index), code_zone());
     ASSERT(result->IsFixed());
     result->kind_ = GENERAL_REGISTERS;
     SetLiveRangeAssignedRegister(result, index);
     fixed_live_ranges_[index] = result;
   }
   return result;
 }
 
 
-LiveRange* LAllocator::FixedDoubleLiveRangeFor(int index) {
+LiveRange* RegisterAllocator::FixedDoubleLiveRangeFor(int index) {
   ASSERT(index < DoubleRegister::NumAllocatableRegisters());
   LiveRange* result = fixed_double_live_ranges_[index];
   if (result == NULL) {
-    result = new(zone()) LiveRange(FixedDoubleLiveRangeID(index),
-                                   chunk()->zone());
+    result = new(zone()) LiveRange(FixedDoubleLiveRangeID(index), code_zone());
     ASSERT(result->IsFixed());
     result->kind_ = DOUBLE_REGISTERS;
     SetLiveRangeAssignedRegister(result, index);
     fixed_double_live_ranges_[index] = result;
   }
   return result;
 }
 
 
-LiveRange* LAllocator::LiveRangeFor(int index) {
+LiveRange* RegisterAllocator::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());
+    result = new(zone()) LiveRange(index, code_zone());
     live_ranges_[index] = result;
   }
   return result;
 }
 
 
-LGap* LAllocator::GetLastGap(HBasicBlock* block) {
+GapInstruction* RegisterAllocator::GetLastGap(BasicBlock* block) {
   int last_instruction = block->last_instruction_index();
-  int index = chunk_->NearestGapPos(last_instruction);
-  return GapAt(index);
+  return code()->GapAt(last_instruction - 1);
 }
 
 
-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) {
+LiveRange* RegisterAllocator::LiveRangeFor(InstructionOperand* operand) {
   if (operand->IsUnallocated()) {
-    return LiveRangeFor(LUnallocated::cast(operand)->virtual_register());
+    return LiveRangeFor(UnallocatedOperand::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) {
+void RegisterAllocator::Define(LifetimePosition position,
+                               InstructionOperand* operand,
+                               InstructionOperand* 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);
+    UnallocatedOperand* unalloc_operand = UnallocatedOperand::cast(operand);
     range->AddUsePosition(position, unalloc_operand, hint, zone());
   }
 }
 
 
-void LAllocator::Use(LifetimePosition block_start,
-                     LifetimePosition position,
-                     LOperand* operand,
-                     LOperand* hint) {
+void RegisterAllocator::Use(LifetimePosition block_start,
+                            LifetimePosition position,
+                            InstructionOperand* operand,
+                            InstructionOperand* hint) {
   LiveRange* range = LiveRangeFor(operand);
   if (range == NULL) return;
   if (operand->IsUnallocated()) {
-    LUnallocated* unalloc_operand = LUnallocated::cast(operand);
+    UnallocatedOperand* unalloc_operand = UnallocatedOperand::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());
+void RegisterAllocator::AddConstraintsGapMove(int index,
+                                              InstructionOperand* from,
+                                              InstructionOperand* to) {
+  GapInstruction* gap = code()->GapAt(index);
+  ParallelMove* move =
+      gap->GetOrCreateParallelMove(GapInstruction::START, code_zone());
   if (from->IsUnallocated()) {
-    const ZoneList<LMoveOperands>* move_operands = move->move_operands();
+    const ZoneList<MoveOperands>* 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();
+      MoveOperands cur = move_operands->at(i);
+      InstructionOperand* 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());
+        if (UnallocatedOperand::cast(cur_to)->virtual_register() ==
+            UnallocatedOperand::cast(from)->virtual_register()) {
+          move->AddMove(cur.source(), to, code_zone());
           return;
         }
       }
     }
   }
-  move->AddMove(from, to, chunk()->zone());
+  move->AddMove(from, to, code_zone());
 }
 
 
-void LAllocator::MeetRegisterConstraints(HBasicBlock* block) {
+void RegisterAllocator::MeetRegisterConstraints(BasicBlock* block) {
   int start = block->first_instruction_index();
   int end = block->last_instruction_index();
-  if (start == -1) return;
+  ASSERT_NE(-1, start);
   for (int i = start; i <= end; ++i) {
-    if (IsGapAt(i)) {
-      LInstruction* instr = NULL;
-      LInstruction* prev_instr = NULL;
+    if (code()->IsGapAt(i)) {
+      Instruction* instr = NULL;
+      Instruction* 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.
+void RegisterAllocator::MeetConstraintsBetween(Instruction* first,
+                                               Instruction* second,
+                                               int gap_index) {
   if (first != NULL) {
-    for (TempIterator it(first); !it.Done(); it.Advance()) {
-      LUnallocated* temp = LUnallocated::cast(it.Current());
+    // Handle fixed temporaries.
+    for (size_t i = 0; i < first->TempCount(); i++) {
+      UnallocatedOperand* temp = UnallocatedOperand::cast(first->TempAt(i));
       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);
+
+    // Handle constant/fixed output operands.
+    for (size_t i = 0; i < first->OutputCount(); i++) {
+      InstructionOperand* output = first->OutputAt(i);
+      if (output->IsConstant()) {
+        int output_vreg = output->index();
+        LiveRange* range = LiveRangeFor(output_vreg);
         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.
+        range->SetSpillOperand(output);
+      } else {
+        UnallocatedOperand* first_output = UnallocatedOperand::cast(output);
+        LiveRange* range = LiveRangeFor(first_output->virtual_register());
+        bool assigned = false;
+        if (first_output->HasFixedPolicy()) {
+          UnallocatedOperand* output_copy =
+              first_output->CopyUnconstrained(code_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;
+          }
+          code()->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.
+          GapInstruction* gap = code()->GapAt(gap_index);
+          ParallelMove* move =
+              gap->GetOrCreateParallelMove(GapInstruction::BEFORE, code_zone());
+          move->AddMove(first_output, range->GetSpillOperand(), code_zone());
+        }
+      }
+    }
+  }
+
   if (second != NULL) {
-    for (UseIterator it(second); !it.Done(); it.Advance()) {
-      LUnallocated* cur_input = LUnallocated::cast(it.Current());
+    // Handle fixed input operands of second instruction.
+    for (size_t i = 0; i < second->InputCount(); i++) {
+      InstructionOperand* input = second->InputAt(i);
+      if (input->IsImmediate()) continue;  // Ignore immediates.
+      UnallocatedOperand* cur_input = UnallocatedOperand::cast(input);
       if (cur_input->HasFixedPolicy()) {
-        LUnallocated* input_copy = cur_input->CopyUnconstrained(
-            chunk()->zone());
+        UnallocatedOperand* input_copy =
+            cur_input->CopyUnconstrained(code_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.
-        ASSERT(!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());
-        }
-
+      }
+    }
+
+    // Handle "output same as input" for second instruction.
+    for (size_t i = 0; i < second->OutputCount(); i++) {
+      InstructionOperand* output = second->Output();
+      if (!output->IsUnallocated()) continue;
+      UnallocatedOperand* second_output = UnallocatedOperand::cast(output);
+      if (second_output->HasSameAsInputPolicy()) {
+        ASSERT(second->OutputCount() == 1);  // Only valid for one output.
+        UnallocatedOperand* cur_input =
+            UnallocatedOperand::cast(second->InputAt(0));
+        int output_vreg = second_output->virtual_register();
+        int input_vreg = cur_input->virtual_register();
+
+        UnallocatedOperand* input_copy =
+            cur_input->CopyUnconstrained(code_zone());
+        cur_input->set_virtual_register(second_output->virtual_register());
         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) {
+
+        if (HasTaggedValue(input_vreg) && !HasTaggedValue(output_vreg)) {
+          int index = gap_index + 1;
+          Instruction* instr = InstructionAt(index);
+          if (instr->HasPointerMap()) {
+            instr->pointer_map()->RecordPointer(input_copy, code_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.
+        }
+      }
+    }
+  }
+}
+
+
+bool RegisterAllocator::IsOutputRegisterOf(
+    Instruction* instr, int index) {
+  for (size_t i = 0; i < instr->OutputCount(); i++) {
+    InstructionOperand* output = instr->OutputAt(i);
+    if (output->IsRegister() && output->index() == index) return true;
+  }
+  return false;
+}
+
+
+bool RegisterAllocator::IsOutputDoubleRegisterOf(
+    Instruction* instr, int index) {
+  for (size_t i = 0; i < instr->OutputCount(); i++) {
+    InstructionOperand* output = instr->OutputAt(i);
+    if (output->IsDoubleRegister() && output->index() == index) return true;
+  }
+  return false;
+}
+
+
+void RegisterAllocator::ProcessInstructions(BasicBlock* 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) {
+  for (int index = block->last_instruction_index();
+       index >= block_start;
+       index--) {
     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();
+    Instruction* instr = InstructionAt(index);
+    ASSERT(instr != NULL);
+    if (instr->IsGapMoves()) {
+      // Process the moves of the gap instruction, making their sources live.
+      GapInstruction* gap = code()->GapAt(index);
+
+      // TODO(titzer): no need to create the parallel move if it doesn't exist.
+      ParallelMove* move =
+          gap->GetOrCreateParallelMove(GapInstruction::START, code_zone());
+      const ZoneList<MoveOperands>* move_operands = move->move_operands();
       for (int i = 0; i < move_operands->length(); ++i) {
-        LMoveOperands* cur = &move_operands->at(i);
+        MoveOperands* 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())) {
+        InstructionOperand* from = cur->source();
+        InstructionOperand* to = cur->destination();
+        InstructionOperand* hint = to;
+        if (to->IsUnallocated()) {
+          int to_vreg = UnallocatedOperand::cast(to)->virtual_register();
+          LiveRange* to_range = LiveRangeFor(to_vreg);
+          if (to_range->is_phi()) {
+            if (to_range->is_non_loop_phi()) {
+              hint = to_range->current_hint_operand();
+            }
+          } else {
+            if (live->Contains(to_vreg)) {
               Define(curr_position, to, from);
-              live->Remove(LUnallocated::cast(to)->virtual_register());
+              live->Remove(to_vreg);
             } else {
               cur->Eliminate();
               continue;
             }
-          } else {
-            Define(curr_position, to, from);
-          }
+          }
+        } else {
+          Define(curr_position, to, from);
         }
         Use(block_start_position, curr_position, from, hint);
         if (from->IsUnallocated()) {
-          live->Add(LUnallocated::cast(from)->virtual_register());
+          live->Add(UnallocatedOperand::cast(from)->virtual_register());
         }
       }
     } else {
-      ASSERT(!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::kMaxNumAllocatableRegisters; ++i) {
-            if (output == NULL || !output->IsRegister() ||
-                output->index() != i) {
-              LiveRange* range = FixedLiveRangeFor(i);
-              range->AddUseInterval(curr_position,
-                                    curr_position.InstructionEnd(),
-                                    zone());
+      // Process output, inputs, and temps of this non-gap instruction.
+      for (size_t i = 0; i < instr->OutputCount(); i++) {
+        InstructionOperand* output = instr->OutputAt(i);
+        if (output->IsUnallocated()) {
+          int out_vreg = UnallocatedOperand::cast(output)->virtual_register();
+          live->Remove(out_vreg);
+        } else if (output->IsConstant()) {
+          int out_vreg = output->index();
+          live->Remove(out_vreg);
+        }
+        Define(curr_position, output, NULL);
+      }
+
+      if (instr->ClobbersRegisters()) {
+        for (int i = 0; i < Register::kMaxNumAllocatableRegisters; ++i) {
+          if (!IsOutputRegisterOf(instr, i)) {
+            LiveRange* range = FixedLiveRangeFor(i);
+            range->AddUseInterval(curr_position,
+                                  curr_position.InstructionEnd(),
+                                  zone());
+          }
+        }
+      }
+
+      if (instr->ClobbersDoubleRegisters()) {
+        for (int i = 0; i < DoubleRegister::NumAllocatableRegisters(); ++i) {
+          if (!IsOutputDoubleRegisterOf(instr, i)) {
+            LiveRange* range = FixedDoubleLiveRangeFor(i);
+            range->AddUseInterval(curr_position,
+                                  curr_position.InstructionEnd(),
+                                  zone());
+          }
+        }
+      }
+
+      for (size_t i = 0; i < instr->InputCount(); i++) {
+        InstructionOperand* input = instr->InputAt(i);
+        if (input->IsImmediate()) continue;  // Ignore immediates.
+        LifetimePosition use_pos;
+        if (input->IsUnallocated() &&
+            UnallocatedOperand::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(UnallocatedOperand::cast(input)->virtual_register());
+        }
+      }
+
+      for (size_t i = 0; i < instr->TempCount(); i++) {
+        InstructionOperand* temp = instr->TempAt(i);
+        if (instr->ClobbersTemps()) {
+          if (temp->IsRegister()) continue;
+          if (temp->IsUnallocated()) {
+            UnallocatedOperand* temp_unalloc = UnallocatedOperand::cast(temp);
+            if (temp_unalloc->HasFixedPolicy()) {
+              continue;
             }
           }
         }
-
-        if (instr->ClobbersDoubleRegisters(isolate())) {
-          for (int i = 0; i < DoubleRegister::NumAllocatableRegisters(); ++i) {
-            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);
+        Use(block_start_position, curr_position.InstructionEnd(), temp, NULL);
+        Define(curr_position, temp, NULL);
+      }
+    }
+  }
+}
+
+
+void RegisterAllocator::ResolvePhis(BasicBlock* block) {
+  for (BasicBlock::const_iterator i = block->begin();
+       i != block->end(); ++i) {
+    Node* phi = *i;
+    if (phi->opcode() != IrOpcode::kPhi) continue;
+
+    UnallocatedOperand* phi_operand =
+        new (code_zone()) UnallocatedOperand(UnallocatedOperand::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 {
-        ASSERT(!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);
+
+    int j = 0;
+    Node::Inputs inputs = phi->inputs();
+    for (Node::Inputs::iterator iter(inputs.begin());
+         iter != inputs.end(); ++iter, ++j) {
+      Node* op = *iter;
+      // TODO(mstarzinger): Use a ValueInputIterator instead.
+      if (j >= block->PredecessorCount()) continue;
+      UnallocatedOperand* operand =
+          new (code_zone()) UnallocatedOperand(UnallocatedOperand::ANY);
+      operand->set_virtual_register(op->id());
+      BasicBlock* cur_block = block->PredecessorAt(j);
       // The gap move must be added without any special processing as in
       // the AddConstraintsGapMove.
-      chunk_->AddGapMove(cur_block->last_instruction_index() - 1,
+      code()->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());
-        }
-      }
+      Instruction* branch = InstructionAt(cur_block->last_instruction_index());
+      ASSERT(!branch->HasPointerMap());
+      USE(branch);
     }
 
     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) {
-  ASSERT(chunk_ == NULL);
-  chunk_ = static_cast<LPlatformChunk*>(chunk);
-  assigned_registers_ =
-      new(chunk->zone()) BitVector(Register::NumAllocatableRegisters(),
-                                   chunk->zone());
-  assigned_double_registers_ =
-      new(chunk->zone()) BitVector(DoubleRegister::NumAllocatableRegisters(),
-                                   chunk->zone());
+    BlockStartInstruction* block_start = code()->GetBlockStart(block);
+    block_start->GetOrCreateParallelMove(GapInstruction::START, code_zone())
+        ->AddMove(phi_operand, live_range->GetSpillOperand(), code_zone());
+    live_range->SetSpillStartIndex(block->first_instruction_index());
+
+    // We use the phi-ness of some nodes in some later heuristics.
+    live_range->set_is_phi(true);
+    if (!block->IsLoopHeader()) {
+      live_range->set_is_non_loop_phi(true);
+    }
+  }
+}
+
+
+bool RegisterAllocator::Allocate() {
+  assigned_registers_ = new(code_zone())
+      BitVector(Register::NumAllocatableRegisters(), code_zone());
+  assigned_double_registers_ = new(code_zone())
+      BitVector(DoubleRegister::NumAllocatableRegisters(), code_zone());
   MeetRegisterConstraints();
   if (!AllocationOk()) return false;
   ResolvePhis();
   BuildLiveRanges();
   AllocateGeneralRegisters();
   if (!AllocationOk()) return false;
   AllocateDoubleRegisters();
   if (!AllocationOk()) return false;
   PopulatePointerMaps();
   ConnectRanges();
   ResolveControlFlow();
+  code()->frame()->SetAllocatedRegisters(assigned_registers_);
+  code()->frame()->SetAllocatedDoubleRegisters(assigned_double_registers_);
   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);
+void RegisterAllocator::MeetRegisterConstraints() {
+  RegisterAllocatorPhase phase("L_Register constraints", this);
+  for (int i = 0; i < code()->BasicBlockCount(); ++i) {
+    MeetRegisterConstraints(code()->BlockAt(i));
     if (!AllocationOk()) return;
   }
 }
 
 
-void LAllocator::ResolvePhis() {
-  LAllocatorPhase phase("L_Resolve phis", this);
+void RegisterAllocator::ResolvePhis() {
+  RegisterAllocatorPhase 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);
+  for (int i = code()->BasicBlockCount() - 1; i >= 0; --i) {
+    ResolvePhis(code()->BlockAt(i));
   }
 }
 
 
-void LAllocator::ResolveControlFlow(LiveRange* range,
-                                    HBasicBlock* block,
-                                    HBasicBlock* pred) {
+void RegisterAllocator::ResolveControlFlow(LiveRange* range,
+                                           BasicBlock* block,
+                                           BasicBlock* 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)) {
       ASSERT(cur_cover == NULL);
       cur_cover = cur_range;
     }
     if (cur_range->CanCover(pred_end)) {
       ASSERT(pred_cover == NULL);
       pred_cover = cur_range;
     }
     cur_range = cur_range->next();
   }
 
   if (cur_cover->IsSpilled()) return;
   ASSERT(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());
+    InstructionOperand* pred_op =
+        pred_cover->CreateAssignedOperand(code_zone());
+    InstructionOperand* cur_op = cur_cover->CreateAssignedOperand(code_zone());
     if (!pred_op->Equals(cur_op)) {
-      LGap* gap = NULL;
-      if (block->predecessors()->length() == 1) {
-        gap = GapAt(block->first_instruction_index());
+      GapInstruction* gap = NULL;
+      if (block->PredecessorCount() == 1) {
+        gap = code()->GapAt(block->first_instruction_index());
       } else {
-        ASSERT(pred->end()->SecondSuccessor() == NULL);
+        ASSERT(pred->SuccessorCount() == 1);
         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);
-          }
-        }
+        Instruction* branch = InstructionAt(pred->last_instruction_index());
+        ASSERT(!branch->HasPointerMap());
+        USE(branch);
       }
-      gap->GetOrCreateParallelMove(
-          LGap::START, chunk()->zone())->AddMove(pred_op, cur_op,
-                                                 chunk()->zone());
+      gap->GetOrCreateParallelMove(GapInstruction::START, code_zone())
+          ->AddMove(pred_op, cur_op, code_zone());
     }
   }
 }
 
 
-LParallelMove* LAllocator::GetConnectingParallelMove(LifetimePosition pos) {
+ParallelMove* RegisterAllocator::GetConnectingParallelMove(
+    LifetimePosition pos) {
   int index = pos.InstructionIndex();
-  if (IsGapAt(index)) {
-    LGap* gap = GapAt(index);
+  if (code()->IsGapAt(index)) {
+    GapInstruction* gap = code()->GapAt(index);
     return gap->GetOrCreateParallelMove(
-        pos.IsInstructionStart() ? LGap::START : LGap::END, chunk()->zone());
+        pos.IsInstructionStart() ? GapInstruction::START : GapInstruction::END,
+        code_zone());
   }
   int gap_pos = pos.IsInstructionStart() ? (index - 1) : (index + 1);
-  return GapAt(gap_pos)->GetOrCreateParallelMove(
-      (gap_pos < index) ? LGap::AFTER : LGap::BEFORE, chunk()->zone());
+  return code()->GapAt(gap_pos)->GetOrCreateParallelMove(
+      (gap_pos < index) ? GapInstruction::AFTER : GapInstruction::BEFORE,
+      code_zone());
 }
 
 
-HBasicBlock* LAllocator::GetBlock(LifetimePosition pos) {
-  LGap* gap = GapAt(chunk_->NearestGapPos(pos.InstructionIndex()));
-  return gap->block();
+BasicBlock* RegisterAllocator::GetBlock(LifetimePosition pos) {
+  return code()->GetBasicBlock(pos.InstructionIndex());
 }
 
 
-void LAllocator::ConnectRanges() {
-  LAllocatorPhase phase("L_Connect ranges", this);
+void RegisterAllocator::ConnectRanges() {
+  RegisterAllocatorPhase 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());
+            ParallelMove* move = GetConnectingParallelMove(pos);
+            InstructionOperand* prev_operand =
+                first_range->CreateAssignedOperand(code_zone());
+            InstructionOperand* cur_operand =
+                second_range->CreateAssignedOperand(code_zone());
             move->AddMove(prev_operand, cur_operand,
-                          chunk()->zone());
+                          code_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;
+bool RegisterAllocator::CanEagerlyResolveControlFlow(BasicBlock* block) const {
+  if (block->PredecessorCount() != 1) return false;
+  return block->PredecessorAt(0)->rpo_number_ == block->rpo_number_ - 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);
+void RegisterAllocator::ResolveControlFlow() {
+  RegisterAllocatorPhase phase("L_Resolve control flow", this);
+  for (int block_id = 1; block_id < code()->BasicBlockCount(); ++block_id) {
+    BasicBlock* block = code()->BlockAt(block_id);
     if (CanEagerlyResolveControlFlow(block)) continue;
-    BitVector* live = live_in_sets_[block->block_id()];
+    BitVector* live = live_in_sets_[block->rpo_number_];
     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);
+      BasicBlock::Predecessors predecessors = block->predecessors();
+      for (BasicBlock::Predecessors::iterator i = predecessors.begin();
+           i != predecessors.end(); ++i) {
+        BasicBlock* cur = *i;
         LiveRange* cur_range = LiveRangeFor(operand_index);
         ResolveControlFlow(cur_range, block, cur);
       }
       iterator.Advance();
     }
   }
 }
 
 
-void LAllocator::BuildLiveRanges() {
-  LAllocatorPhase phase("L_Build live ranges", this);
+void RegisterAllocator::BuildLiveRanges() {
+  RegisterAllocatorPhase 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);
+  for (int block_id = code()->BasicBlockCount() - 1;
+       block_id >= 0; --block_id) {
+    BasicBlock* block = code()->BlockAt(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) {
+    for (BasicBlock::const_iterator i = block->begin();
+         i != block->end(); ++i) {
+      Node* phi = *i;
+      if (phi->opcode() != IrOpcode::kPhi) continue;
+
       // 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());
+      InstructionOperand* hint = NULL;
+      InstructionOperand* phi_operand = NULL;
+      GapInstruction* gap = GetLastGap(block->PredecessorAt(0));
+
+      // TODO(titzer): no need to create the parallel move if it doesn't exit.
+      ParallelMove* move =
+          gap->GetOrCreateParallelMove(GapInstruction::START, code_zone());
       for (int j = 0; j < move->move_operands()->length(); ++j) {
-        LOperand* to = move->move_operands()->at(j).destination();
+        InstructionOperand* to = move->move_operands()->at(j).destination();
         if (to->IsUnallocated() &&
-            LUnallocated::cast(to)->virtual_register() == phi->id()) {
+            UnallocatedOperand::cast(to)->virtual_register() == phi->id()) {
           hint = move->move_operands()->at(j).source();
           phi_operand = to;
           break;
         }
       }
       ASSERT(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();
+      // Add a live range stretching from the first loop instruction to the last
+      // for each value live on entry to the header.
       BitVector::Iterator iterator(live);
       LifetimePosition start = LifetimePosition::FromInstructionIndex(
           block->first_instruction_index());
+      int end_index =
+          code()->BlockAt(block->loop_end_)->last_instruction_index();
       LifetimePosition end = LifetimePosition::FromInstructionIndex(
-          back_edge->last_instruction_index()).NextInstruction();
+          end_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) {
+      // Insert all values into the live in sets of all blocks in the loop.
+      for (int i = block->rpo_number_ + 1; i < block->loop_end_; ++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();
-        if (chunk_->info()->IsStub()) {
-          CodeStub::Major major_key = chunk_->info()->code_stub()->MajorKey();
-          PrintF("Function: %s\n", CodeStub::MajorName(major_key, false));
+        PrintF("Register allocator error: live v%d reached first block.\n",
+               operand_index);
+        LiveRange* range = LiveRangeFor(operand_index);
+        PrintF("  (first use is at %d)\n", range->first_pos()->pos().Value());
+        CompilationInfo* info = code()->linkage()->info();
+        if (info->IsStub()) {
+          if (info->code_stub() == NULL) {
+            PrintF("\n");
+          } else {
+            CodeStub::Major major_key = info->code_stub()->MajorKey();
+            PrintF("  (function: %s)\n", CodeStub::MajorName(major_key, false));
+          }
         } else {
-          ASSERT(chunk_->info()->IsOptimizing());
+          ASSERT(info->IsOptimizing());
           AllowHandleDereference allow_deref;
-          PrintF("Function: %s\n",
-                 chunk_->info()->function()->debug_name()->ToCString().get());
+          PrintF("  (function: %s)\n",
+                 info->function()->debug_name()->ToCString().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();
       }
       ASSERT(!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());
+
+      // TODO(bmeurer): This is a horrible hack to make sure that for constant
+      // live ranges, every use requires the constant to be in a register.
+      // Without this hack, all uses with "any" policy would get the constant
+      // operand assigned.
+      LiveRange* range = live_ranges_[i];
+      if (range->HasAllocatedSpillOperand() &&
+          range->GetSpillOperand()->IsConstant()) {
+        for (UsePosition* pos = range->first_pos(); pos != NULL;
+             pos = pos->next_) {
+          pos->register_beneficial_ = true;
+          pos->requires_reg_ = true;
+        }
+      }
     }
   }
 }
 
 
-bool LAllocator::SafePointsAreInOrder() const {
-  const ZoneList<LPointerMap*>* pointer_maps = chunk_->pointer_maps();
+bool RegisterAllocator::SafePointsAreInOrder() const {
   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();
+  const PointerMapDeque* pointer_maps = code()->pointer_maps();
+  for (PointerMapDeque::const_iterator it = pointer_maps->begin();
+       it != pointer_maps->end(); ++it) {
+    PointerMap* map = *it;
+    if (safe_point > map->instruction_position()) return false;
+    safe_point = map->instruction_position();
   }
   return true;
 }
 
 
-void LAllocator::PopulatePointerMaps() {
-  LAllocatorPhase phase("L_Populate pointer maps", this);
-  const ZoneList<LPointerMap*>* pointer_maps = chunk_->pointer_maps();
+void RegisterAllocator::PopulatePointerMaps() {
+  RegisterAllocatorPhase phase("L_Populate pointer maps", this);
 
   ASSERT(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;
+  const PointerMapDeque* pointer_maps = code()->pointer_maps();
+  PointerMapDeque::const_iterator first_it = pointer_maps->begin();
   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.
+    // Skip non-reference 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();
       ASSERT(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;
-    }
+    // Most of the ranges are in order, but not all.  Keep an eye on when they
+    // step backwards and reset the first_it so we don't miss any safe points.
+    if (start < last_range_start) first_it = pointer_maps->begin();
     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++;
+    for (; first_it != pointer_maps->end(); ++first_it) {
+      PointerMap* map = *first_it;
+      if (map->instruction_position() >= start) break;
     }
 
     // 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();
+    for (PointerMapDeque::const_iterator it = first_it;
+         it != pointer_maps->end(); ++it) {
+      PointerMap* map = *it;
+      int safe_point = map->instruction_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()) {
+          safe_point >= range->spill_start_index() &&
+          !range->GetSpillOperand()->IsConstant()) {
         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());
+        map->RecordPointer(range->GetSpillOperand(), code_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());
+        InstructionOperand* operand = cur->CreateAssignedOperand(code_zone());
         ASSERT(!operand->IsStackSlot());
-        map->RecordPointer(operand, chunk()->zone());
+        map->RecordPointer(operand, code_zone());
       }
     }
   }
 }
 
 
-void LAllocator::AllocateGeneralRegisters() {
-  LAllocatorPhase phase("L_Allocate general registers", this);
+void RegisterAllocator::AllocateGeneralRegisters() {
+  RegisterAllocatorPhase phase("L_Allocate general registers", this);
   num_registers_ = Register::NumAllocatableRegisters();
   mode_ = GENERAL_REGISTERS;
   AllocateRegisters();
 }
 
 
-void LAllocator::AllocateDoubleRegisters() {
-  LAllocatorPhase phase("L_Allocate double registers", this);
+void RegisterAllocator::AllocateDoubleRegisters() {
+  RegisterAllocatorPhase phase("L_Allocate double registers", this);
   num_registers_ = DoubleRegister::NumAllocatableRegisters();
   mode_ = DOUBLE_REGISTERS;
   AllocateRegisters();
 }
 
 
-void LAllocator::AllocateRegisters() {
+void RegisterAllocator::AllocateRegisters() {
   ASSERT(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();
@@ skipping 28 matching lines @@
 #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())) {
+      if (code()->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()) {
@@ skipping 40 matching lines @@
       AddToActive(current);
     }
   }
 
   reusable_slots_.Rewind(0);
   active_live_ranges_.Rewind(0);
   inactive_live_ranges_.Rewind(0);
 }
 
 
-const char* LAllocator::RegisterName(int allocation_index) {
+const char* RegisterAllocator::RegisterName(int allocation_index) {
   if (mode_ == GENERAL_REGISTERS) {
     return Register::AllocationIndexToString(allocation_index);
   } else {
     return DoubleRegister::AllocationIndexToString(allocation_index);
   }
 }
 
 
-void LAllocator::TraceAlloc(const char* msg, ...) {
+void RegisterAllocator::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();
+bool RegisterAllocator::HasTaggedValue(int virtual_register) const {
+  return code()->IsReference(virtual_register);
 }
 
 
-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;
+RegisterKind RegisterAllocator::RequiredRegisterKind(
+    int virtual_register) const {
+  return (code()->IsDouble(virtual_register)) ? DOUBLE_REGISTERS
+                                              : GENERAL_REGISTERS;
 }
 
 
-void LAllocator::AddToActive(LiveRange* range) {
+void RegisterAllocator::AddToActive(LiveRange* range) {
   TraceAlloc("Add live range %d to active\n", range->id());
   active_live_ranges_.Add(range, zone());
 }
 
 
-void LAllocator::AddToInactive(LiveRange* range) {
+void RegisterAllocator::AddToInactive(LiveRange* range) {
   TraceAlloc("Add live range %d to inactive\n", range->id());
   inactive_live_ranges_.Add(range, zone());
 }
 
 
-void LAllocator::AddToUnhandledSorted(LiveRange* range) {
+void RegisterAllocator::AddToUnhandledSorted(LiveRange* range) {
   if (range == NULL || range->IsEmpty()) return;
   ASSERT(!range->HasRegisterAssigned() && !range->IsSpilled());
   ASSERT(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());
       ASSERT(UnhandledIsSorted());
       return;
     }
   }
   TraceAlloc("Add live range %d to unhandled at start\n", range->id());
   unhandled_live_ranges_.InsertAt(0, range, zone());
   ASSERT(UnhandledIsSorted());
 }
 
 
-void LAllocator::AddToUnhandledUnsorted(LiveRange* range) {
+void RegisterAllocator::AddToUnhandledUnsorted(LiveRange* range) {
   if (range == NULL || range->IsEmpty()) return;
   ASSERT(!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) {
   ASSERT(!(*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() {
+void RegisterAllocator::SortUnhandled() {
   TraceAlloc("Sort unhandled\n");
   unhandled_live_ranges_.Sort(&UnhandledSortHelper);
 }
 
 
-bool LAllocator::UnhandledIsSorted() {
+bool RegisterAllocator::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) {
+void RegisterAllocator::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) {
+  InstructionOperand* spill_operand = range->TopLevel()->GetSpillOperand();
+  if (spill_operand->IsConstant()) return;
+  if (spill_operand->index() >= 0) {
     reusable_slots_.Add(range, zone());
   }
 }
 
 
-LOperand* LAllocator::TryReuseSpillSlot(LiveRange* range) {
+InstructionOperand* RegisterAllocator::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();
+  InstructionOperand* result =
+      reusable_slots_.first()->TopLevel()->GetSpillOperand();
   reusable_slots_.Remove(0);
   return result;
 }
 
 
-void LAllocator::ActiveToHandled(LiveRange* range) {
+void RegisterAllocator::ActiveToHandled(LiveRange* range) {
   ASSERT(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) {
+void RegisterAllocator::ActiveToInactive(LiveRange* range) {
   ASSERT(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) {
+void RegisterAllocator::InactiveToHandled(LiveRange* range) {
   ASSERT(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) {
+void RegisterAllocator::InactiveToActive(LiveRange* range) {
   ASSERT(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());
 }
 
 
 // TryAllocateFreeReg and AllocateBlockedReg assume this
 // when allocating local arrays.
 STATIC_ASSERT(DoubleRegister::kMaxNumAllocatableRegisters >=
               Register::kMaxNumAllocatableRegisters);
 
 
-bool LAllocator::TryAllocateFreeReg(LiveRange* current) {
+bool RegisterAllocator::TryAllocateFreeReg(LiveRange* current) {
   LifetimePosition free_until_pos[DoubleRegister::kMaxNumAllocatableRegisters];
 
   for (int i = 0; i < num_registers_; 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);
     ASSERT(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();
+  InstructionOperand* 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.
@@ skipping 35 matching lines @@
   ASSERT(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) {
+void RegisterAllocator::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::kMaxNumAllocatableRegisters];
@@ skipping 67 matching lines @@
              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 RegisterAllocator::FindOptimalSpillingPos(LiveRange* range,
                                                     LifetimePosition pos) {
-  HBasicBlock* block = GetBlock(pos.InstructionStart());
-  HBasicBlock* loop_header =
-      block->IsLoopHeader() ? block : block->parent_loop_header();
+  BasicBlock* block = GetBlock(pos.InstructionStart());
+  BasicBlock* loop_header =
+      block->IsLoopHeader() ? block : code()->GetContainingLoop(block);
 
   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();
+    loop_header = code()->GetContainingLoop(loop_header);
   }
 
   return pos;
 }
 
 
-void LAllocator::SplitAndSpillIntersecting(LiveRange* current) {
+void RegisterAllocator::SplitAndSpillIntersecting(LiveRange* current) {
   ASSERT(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);
@@ skipping 29 matching lines @@
         }
         if (!AllocationOk()) return;
         InactiveToHandled(range);
         --i;
       }
     }
   }
 }
 
 
-bool LAllocator::IsBlockBoundary(LifetimePosition pos) {
+bool RegisterAllocator::IsBlockBoundary(LifetimePosition pos) {
   return pos.IsInstructionStart() &&
-      InstructionAt(pos.InstructionIndex())->IsLabel();
+      InstructionAt(pos.InstructionIndex())->IsBlockStart();
 }
 
 
-LiveRange* LAllocator::SplitRangeAt(LiveRange* range, LifetimePosition pos) {
+LiveRange* RegisterAllocator::SplitRangeAt(LiveRange* range,
+    LifetimePosition pos) {
   ASSERT(!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.
   ASSERT(pos.IsInstructionStart() ||
-         !chunk_->instructions()->at(pos.InstructionIndex())->IsControl());
+         !InstructionAt(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,
+LiveRange* RegisterAllocator::SplitBetween(LiveRange* range,
                                     LifetimePosition start,
                                     LifetimePosition end) {
   ASSERT(!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);
   ASSERT(split_pos.Value() >= start.Value());
   return SplitRangeAt(range, split_pos);
 }
 
 
-LifetimePosition LAllocator::FindOptimalSplitPos(LifetimePosition start,
+LifetimePosition RegisterAllocator::FindOptimalSplitPos(LifetimePosition start,
                                                  LifetimePosition end) {
   int start_instr = start.InstructionIndex();
   int end_instr = end.InstructionIndex();
   ASSERT(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);
+  BasicBlock* start_block = GetBlock(start);
+  BasicBlock* 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;
+  BasicBlock* 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();
+  // TODO(titzer): fix redundancy below.
+  while (code()->GetContainingLoop(block) != NULL &&
+         code()->GetContainingLoop(block)->rpo_number_ >
+         start_block->rpo_number_) {
+    block = code()->GetContainingLoop(block);
   }
 
   // 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) {
+void RegisterAllocator::SpillAfter(LiveRange* range, LifetimePosition pos) {
   LiveRange* second_part = SplitRangeAt(range, pos);
   if (!AllocationOk()) return;
   Spill(second_part);
 }
 
 
-void LAllocator::SpillBetween(LiveRange* range,
+void RegisterAllocator::SpillBetween(LiveRange* range,
                               LifetimePosition start,
                               LifetimePosition end) {
   SpillBetweenUntil(range, start, start, end);
 }
 
 
-void LAllocator::SpillBetweenUntil(LiveRange* range,
+void RegisterAllocator::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;
 
     ASSERT(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) {
+void RegisterAllocator::Spill(LiveRange* range) {
   ASSERT(!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());
+    InstructionOperand* op = TryReuseSpillSlot(range);
+    if (op == NULL) {
+      // Allocate a new operand referring to the spill slot.
+      RegisterKind kind = range->Kind();
+      int index = code()->frame()->AllocateSpillSlot(kind == DOUBLE_REGISTERS);
+      if (kind == DOUBLE_REGISTERS) {
+        op = DoubleStackSlotOperand::Create(index, zone());
+      } else {
+        ASSERT(kind == GENERAL_REGISTERS);
+        op = StackSlotOperand::Create(index, zone());
+      }
+    }
     first->SetSpillOperand(op);
   }
-  range->MakeSpilled(chunk()->zone());
+  range->MakeSpilled(code_zone());
 }
 
 
-int LAllocator::RegisterCount() const {
+int RegisterAllocator::RegisterCount() const {
   return num_registers_;
 }
 
 
 #ifdef DEBUG
 
 
-void LAllocator::Verify() const {
+void RegisterAllocator::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()),
+void RegisterAllocator::SetLiveRangeAssignedRegister(LiveRange* range,
+                                                     int reg) {
+  if (range->Kind() == DOUBLE_REGISTERS) {
+    assigned_double_registers_->Add(reg);
+  } else {
+    ASSERT(range->Kind() == GENERAL_REGISTERS);
+    assigned_registers_->Add(reg);
+  }
+  range->set_assigned_register(reg, code_zone());
+}
+
+
+RegisterAllocatorPhase::RegisterAllocatorPhase(const char* name,
+                                               RegisterAllocator* allocator)
+    : CompilationPhase(name, allocator->code()->linkage()->info()),
       allocator_(allocator) {
-  if (FLAG_hydrogen_stats) {
+  if (FLAG_turbo_stats) {
     allocator_zone_start_allocation_size_ =
         allocator->zone()->allocation_size();
   }
 }
 
 
-LAllocatorPhase::~LAllocatorPhase() {
-  if (FLAG_hydrogen_stats) {
+RegisterAllocatorPhase::~RegisterAllocatorPhase() {
+  if (FLAG_turbo_stats) {
     unsigned size = allocator_->zone()->allocation_size() -
                     allocator_zone_start_allocation_size_;
-    isolate()->GetHStatistics()->SaveTiming(name(), base::TimeDelta(), size);
+    isolate()->GetTStatistics()->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 v8::internal
+} } }  // namespace v8::internal::compiler