Refactor register allocator a little bit

src/lithium-allocator.h

 // 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 128 matching lines @@
   // Code relies on kStep being a power of two.
   STATIC_ASSERT(IS_POWER_OF_TWO(kStep));
 
   explicit LifetimePosition(int value) : value_(value) { }
 
   int value_;
 };
 
 
 enum RegisterKind {
+  UNALLOCATED_REGISTERS,
   GENERAL_REGISTERS,
   DOUBLE_REGISTERS
 };
 
 
 // A register-allocator view of a Lithium instruction. It contains the id of
 // the output operand and a list of input operand uses.
 
 class LInstruction;
 class LEnvironment;
@@ skipping 124 matching lines @@
   LiveRange* parent() const { return parent_; }
   LiveRange* TopLevel() { return (parent_ == NULL) ? this : parent_; }
   LiveRange* next() const { return next_; }
   bool IsChild() const { return parent() != NULL; }
   int id() const { return id_; }
   bool IsFixed() const { return id_ < 0; }
   bool IsEmpty() const { return first_interval() == NULL; }
   LOperand* CreateAssignedOperand(Zone* zone);
   int assigned_register() const { return assigned_register_; }
   int spill_start_index() const { return spill_start_index_; }
-  void set_assigned_register(int reg,
-                             RegisterKind register_kind,
-                             Zone* zone);
+  void set_assigned_register(int reg, Zone* zone);
   void MakeSpilled(Zone* zone);
 
   // Returns use position in this live range that follows both start
   // and last processed use position.
   // Modifies internal state of live range!
   UsePosition* NextUsePosition(LifetimePosition start);
 
   // Returns use position for which register is required in this live
   // range and which follows both start and last processed use position
   // Modifies internal state of live range!
@@ skipping 10 matching lines @@
 
   // Can this live range be spilled at this position.
   bool CanBeSpilled(LifetimePosition pos);
 
   // Split this live range at the given position which must follow the start of
   // the range.
   // All uses following the given position will be moved from this
   // live range to the result live range.
   void SplitAt(LifetimePosition position, LiveRange* result, Zone* zone);
 
-  bool IsDouble() const { return is_double_; }
+  RegisterKind Kind() const { return kind_; }
   bool HasRegisterAssigned() const {
     return assigned_register_ != kInvalidAssignment;
   }
   bool IsSpilled() const { return spilled_; }
 
   LOperand* current_hint_operand() const {
     ASSERT(current_hint_operand_ == FirstHint());
     return current_hint_operand_;
   }
   LOperand* FirstHint() const {
@@ skipping 48 matching lines @@
 #endif
 
  private:
   void ConvertOperands(Zone* zone);
   UseInterval* FirstSearchIntervalForPosition(LifetimePosition position) const;
   void AdvanceLastProcessedMarker(UseInterval* to_start_of,
                                   LifetimePosition but_not_past) const;
 
   int id_;
   bool spilled_;
-  bool is_double_;
+  RegisterKind kind_;
   int assigned_register_;
   UseInterval* last_interval_;
   UseInterval* first_interval_;
   UsePosition* first_pos_;
   LiveRange* parent_;
   LiveRange* next_;
   // This is used as a cache, it doesn't affect correctness.
   mutable UseInterval* current_interval_;
   UsePosition* last_processed_use_;
   // This is used as a cache, it's invalid outside of BuildLiveRanges.
   LOperand* current_hint_operand_;
   LOperand* spill_operand_;
   int spill_start_index_;
+
+  friend class LAllocator;  // Assigns to kind_.
 };
 
 
 class LAllocator BASE_EMBEDDED {
  public:
   LAllocator(int first_virtual_register, HGraph* graph);
 
   static void TraceAlloc(const char* msg, ...);
 
   // Checks whether the value of a given virtual register is tagged.
@@ skipping 142 matching lines @@
                                           LifetimePosition pos);
 
   void Spill(LiveRange* range);
   bool IsBlockBoundary(LifetimePosition pos);
 
   // Helper methods for resolving control flow.
   void ResolveControlFlow(LiveRange* range,
                           HBasicBlock* block,
                           HBasicBlock* pred);
 
-  inline void SetLiveRangeAssignedRegister(LiveRange* range,
-                                           int reg,
-                                           RegisterKind register_kind);
+  inline void SetLiveRangeAssignedRegister(LiveRange* range, int reg);
 
   // Return parallel move that should be used to connect ranges split at the
   // given position.
   LParallelMove* GetConnectingParallelMove(LifetimePosition pos);
 
   // Return the block which contains give lifetime position.
   HBasicBlock* GetBlock(LifetimePosition pos);
 
   // Helper methods for the fixed registers.
   int RegisterCount() const;
@@ skipping 69 matching lines @@
   LAllocator* allocator_;
   unsigned allocator_zone_start_allocation_size_;
 
   DISALLOW_COPY_AND_ASSIGN(LAllocatorPhase);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_LITHIUM_ALLOCATOR_H_