Refactor register allocator a little bit

src/lithium-allocator.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 113 matching lines @@
   return false;
 }
 
 
 #endif
 
 
 LiveRange::LiveRange(int id, Zone* zone)
     : id_(id),
       spilled_(false),
-      is_double_(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,
-                                      RegisterKind register_kind,
-                                      Zone* zone) {
+void LiveRange::set_assigned_register(int reg, Zone* zone) {
   ASSERT(!HasRegisterAssigned() && !IsSpilled());
   assigned_register_ = reg;
-  is_double_ = (register_kind == DOUBLE_REGISTERS);
   ConvertOperands(zone);
 }
 
 
 void LiveRange::MakeSpilled(Zone* zone) {
   ASSERT(!IsSpilled());
   ASSERT(TopLevel()->HasAllocatedSpillOperand());
   spilled_ = true;
   assigned_register_ = kInvalidAssignment;
   ConvertOperands(zone);
@@ skipping 63 matching lines @@
   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()) {
     ASSERT(!IsSpilled());
-    if (IsDouble()) {
-      op = LDoubleRegister::Create(assigned_register(), zone);
-    } else {
-      op = LRegister::Create(assigned_register(), zone);
+    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()) {
     ASSERT(!HasRegisterAssigned());
     op = TopLevel()->GetSpillOperand();
     ASSERT(!op->IsUnallocated());
   } else {
     LUnallocated* unalloc = new(zone) LUnallocated(LUnallocated::NONE);
     unalloc->set_virtual_register(id_);
     op = unalloc;
   }
@@ skipping 94 matching lines @@
   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
 }
 
 
@@ skipping 181 matching lines @@
       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_(GENERAL_REGISTERS),
+      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());
@@ skipping 79 matching lines @@
   return operand;
 }
 
 
 LiveRange* LAllocator::FixedLiveRangeFor(int index) {
   ASSERT(index < Register::kMaxNumAllocatableRegisters);
   LiveRange* result = fixed_live_ranges_[index];
   if (result == NULL) {
     result = new(zone()) LiveRange(FixedLiveRangeID(index), chunk()->zone());
     ASSERT(result->IsFixed());
-    SetLiveRangeAssignedRegister(result, index, GENERAL_REGISTERS);
+    result->kind_ = GENERAL_REGISTERS;
+    SetLiveRangeAssignedRegister(result, index);
     fixed_live_ranges_[index] = result;
   }
   return result;
 }
 
 
 LiveRange* LAllocator::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());
     ASSERT(result->IsFixed());
-    SetLiveRangeAssignedRegister(result, index, DOUBLE_REGISTERS);
+    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());
   }
@@ skipping 687 matching lines @@
         }
         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());
+    }
+  }
 }
 
 
 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();
@@ skipping 86 matching lines @@
         map->RecordPointer(operand, chunk()->zone());
       }
     }
   }
 }
 
 
 void LAllocator::AllocateGeneralRegisters() {
   LAllocatorPhase phase("L_Allocate general registers", this);
   num_registers_ = Register::NumAllocatableRegisters();
+  mode_ = GENERAL_REGISTERS;
   AllocateRegisters();
 }
 
 
 void LAllocator::AllocateDoubleRegisters() {
   LAllocatorPhase phase("L_Allocate double registers", this);
   num_registers_ = DoubleRegister::NumAllocatableRegisters();
   mode_ = DOUBLE_REGISTERS;
   AllocateRegisters();
 }
 
 
 void LAllocator::AllocateRegisters() {
   ASSERT(unhandled_live_ranges_.is_empty());
 
   for (int i = 0; i < live_ranges_.length(); ++i) {
     if (live_ranges_[i] != NULL) {
-      if (RequiredRegisterKind(live_ranges_[i]->id()) == mode_) {
+      if (live_ranges_[i]->Kind() == mode_) {
         AddToUnhandledUnsorted(live_ranges_[i]);
       }
     }
   }
   SortUnhandled();
   ASSERT(UnhandledIsSorted());
 
   ASSERT(reusable_slots_.is_empty());
   ASSERT(active_live_ranges_.is_empty());
   ASSERT(inactive_live_ranges_.is_empty());
 
   if (mode_ == DOUBLE_REGISTERS) {
     for (int i = 0; i < DoubleRegister::NumAllocatableRegisters(); ++i) {
       LiveRange* current = fixed_double_live_ranges_.at(i);
       if (current != NULL) {
         AddToInactive(current);
       }
     }
   } else {
+    ASSERT(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()) {
     ASSERT(UnhandledIsSorted());
@@ skipping 274 matching lines @@
         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, mode_);
+      SetLiveRangeAssignedRegister(current, register_index);
       return true;
     }
   }
 
   // Find the register which stays free for the longest time.
   int reg = 0;
   for (int i = 1; i < RegisterCount(); ++i) {
     if (free_until_pos[i].Value() > free_until_pos[reg].Value()) {
       reg = i;
     }
@@ skipping 14 matching lines @@
     AddToUnhandledSorted(tail);
   }
 
 
   // Register reg is available at the range start and is free until
   // the range end.
   ASSERT(pos.Value() >= current->End().Value());
   TraceAlloc("Assigning free reg %s to live range %d\n",
              RegisterName(reg),
              current->id());
-  SetLiveRangeAssignedRegister(current, reg, mode_);
+  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.
@@ skipping 64 matching lines @@
                                    block_pos[reg].InstructionStart());
     if (!AllocationOk()) return;
     AddToUnhandledSorted(tail);
   }
 
   // Register reg is not blocked for the whole range.
   ASSERT(block_pos[reg].Value() >= current->End().Value());
   TraceAlloc("Assigning blocked reg %s to live range %d\n",
              RegisterName(reg),
              current->id());
-  SetLiveRangeAssignedRegister(current, reg, mode_);
+  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) {
@@ skipping 196 matching lines @@
 }
 
 
 void LAllocator::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(mode_ == DOUBLE_REGISTERS);
+    if (op == NULL) op = chunk_->GetNextSpillSlot(range->Kind());
     first->SetSpillOperand(op);
   }
   range->MakeSpilled(chunk()->zone());
 }
 
 
 int LAllocator::RegisterCount() const {
   return num_registers_;
 }
 
@@ skipping 34 matching lines @@
     isolate()->GetHTracer()->TraceLiveRanges(name(), allocator_);
   }
 
 #ifdef DEBUG
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 
 } }  // namespace v8::internal