Land the Fan (disabled)

src/compiler/register-allocator.h

-// 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.
 
-#ifndef V8_LITHIUM_ALLOCATOR_H_
-#define V8_LITHIUM_ALLOCATOR_H_
-
-#include "src/v8.h"
+#ifndef V8_REGISTER_ALLOCATOR_H_
+#define V8_REGISTER_ALLOCATOR_H_
 
 #include "src/allocation.h"
-#include "src/lithium.h"
+#include "src/compiler/instruction.h"
+#include "src/compiler/node.h"
+#include "src/compiler/schedule.h"
+#include "src/macro-assembler.h"
 #include "src/zone.h"
 
 namespace v8 {
 namespace internal {
 
 // Forward declarations.
-class HBasicBlock;
-class HGraph;
-class HInstruction;
-class HPhi;
-class HTracer;
-class HValue;
 class BitVector;
-class StringStream;
+class InstructionOperand;
+class UnallocatedOperand;
+class ParallelMove;
+class PointerMap;
 
-class LPlatformChunk;
-class LOperand;
-class LUnallocated;
-class LGap;
-class LParallelMove;
-class LPointerMap;
+namespace compiler {
+
+enum RegisterKind {
+  UNALLOCATED_REGISTERS,
+  GENERAL_REGISTERS,
+  DOUBLE_REGISTERS
+};
 
 
-// This class represents a single point of a LOperand's lifetime.
-// For each lithium instruction there are exactly two lifetime positions:
-// the beginning and the end of the instruction. Lifetime positions for
-// different lithium instructions are disjoint.
+// This class represents a single point of a InstructionOperand's lifetime. For
+// each instruction there are exactly two lifetime positions: the beginning and
+// the end of the instruction. Lifetime positions for different instructions are
+// disjoint.
 class LifetimePosition {
  public:
   // Return the lifetime position that corresponds to the beginning of
   // the instruction with the given index.
   static LifetimePosition FromInstructionIndex(int index) {
     return LifetimePosition(index * kStep);
   }
 
   // Returns a numeric representation of this lifetime position.
   int Value() const {
@@ skipping 62 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;
-
-// Iterator for non-null temp operands.
-class TempIterator BASE_EMBEDDED {
- public:
-  inline explicit TempIterator(LInstruction* instr);
-  inline bool Done();
-  inline LOperand* Current();
-  inline void Advance();
-
- private:
-  inline void SkipUninteresting();
-  LInstruction* instr_;
-  int limit_;
-  int current_;
-};
-
-
-// Iterator for non-constant input operands.
-class InputIterator BASE_EMBEDDED {
- public:
-  inline explicit InputIterator(LInstruction* instr);
-  inline bool Done();
-  inline LOperand* Current();
-  inline void Advance();
-
- private:
-  inline void SkipUninteresting();
-  LInstruction* instr_;
-  int limit_;
-  int current_;
-};
-
-
-class UseIterator BASE_EMBEDDED {
- public:
-  inline explicit UseIterator(LInstruction* instr);
-  inline bool Done();
-  inline LOperand* Current();
-  inline void Advance();
-
- private:
-  InputIterator input_iterator_;
-  DeepIterator env_iterator_;
-};
-
-
 // Representation of the non-empty interval [start,end[.
 class UseInterval: public ZoneObject {
  public:
   UseInterval(LifetimePosition start, LifetimePosition end)
       : start_(start), end_(end), next_(NULL) {
     ASSERT(start.Value() < end.Value());
   }
 
   LifetimePosition start() const { return start_; }
   LifetimePosition end() const { return end_; }
   UseInterval* next() const { return next_; }
 
   // Split this interval at the given position without effecting the
   // live range that owns it. The interval must contain the position.
   void SplitAt(LifetimePosition pos, Zone* zone);
 
   // If this interval intersects with other return smallest position
   // that belongs to both of them.
   LifetimePosition Intersect(const UseInterval* other) const {
     if (other->start().Value() < start_.Value()) return other->Intersect(this);
     if (other->start().Value() < end_.Value()) return other->start();
     return LifetimePosition::Invalid();
   }
 
   bool Contains(LifetimePosition point) const {
     return start_.Value() <= point.Value() && point.Value() < end_.Value();
   }
 
- private:
   void set_start(LifetimePosition start) { start_ = start; }
   void set_next(UseInterval* next) { next_ = next; }
 
   LifetimePosition start_;
   LifetimePosition end_;
   UseInterval* next_;
-
-  friend class LiveRange;  // Assigns to start_.
 };
 
 // Representation of a use position.
 class UsePosition: public ZoneObject {
  public:
-  UsePosition(LifetimePosition pos, LOperand* operand, LOperand* hint);
+  UsePosition(LifetimePosition pos, InstructionOperand* operand,
+              InstructionOperand* hint);
 
-  LOperand* operand() const { return operand_; }
+  InstructionOperand* operand() const { return operand_; }
   bool HasOperand() const { return operand_ != NULL; }
 
-  LOperand* hint() const { return hint_; }
+  InstructionOperand* hint() const { return hint_; }
   bool HasHint() const;
   bool RequiresRegister() const;
   bool RegisterIsBeneficial() const;
 
   LifetimePosition pos() const { return pos_; }
   UsePosition* next() const { return next_; }
 
- private:
   void set_next(UsePosition* next) { next_ = next; }
 
-  LOperand* const operand_;
-  LOperand* const hint_;
+  InstructionOperand* const operand_;
+  InstructionOperand* const hint_;
   LifetimePosition const pos_;
   UsePosition* next_;
   bool requires_reg_;
   bool register_beneficial_;
-
-  friend class LiveRange;
 };
 
 // Representation of SSA values' live ranges as a collection of (continuous)
 // intervals over the instruction ordering.
 class LiveRange: public ZoneObject {
  public:
   static const int kInvalidAssignment = 0x7fffffff;
 
   LiveRange(int id, Zone* zone);
 
   UseInterval* first_interval() const { return first_interval_; }
   UsePosition* first_pos() const { return first_pos_; }
   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);
+  InstructionOperand* 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, Zone* zone);
   void MakeSpilled(Zone* zone);
+  bool is_phi() const { return is_phi_; }
+  void set_is_phi(bool is_phi) { is_phi_ = is_phi; }
+  bool is_non_loop_phi() const { return is_non_loop_phi_; }
+  void set_is_non_loop_phi(bool is_non_loop_phi) {
+    is_non_loop_phi_ = is_non_loop_phi;
+  }
 
   // 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!
   UsePosition* NextRegisterPosition(LifetimePosition start);
@@ skipping 15 matching lines @@
   // 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);
 
   RegisterKind Kind() const { return kind_; }
   bool HasRegisterAssigned() const {
     return assigned_register_ != kInvalidAssignment;
   }
   bool IsSpilled() const { return spilled_; }
 
-  LOperand* current_hint_operand() const {
+  InstructionOperand* current_hint_operand() const {
     ASSERT(current_hint_operand_ == FirstHint());
     return current_hint_operand_;
   }
-  LOperand* FirstHint() const {
+  InstructionOperand* FirstHint() const {
     UsePosition* pos = first_pos_;
     while (pos != NULL && !pos->HasHint()) pos = pos->next();
     if (pos != NULL) return pos->hint();
     return NULL;
   }
 
   LifetimePosition Start() const {
     ASSERT(!IsEmpty());
     return first_interval()->start();
   }
 
   LifetimePosition End() const {
     ASSERT(!IsEmpty());
     return last_interval_->end();
   }
 
   bool HasAllocatedSpillOperand() const;
-  LOperand* GetSpillOperand() const { return spill_operand_; }
-  void SetSpillOperand(LOperand* operand);
+  InstructionOperand* GetSpillOperand() const { return spill_operand_; }
+  void SetSpillOperand(InstructionOperand* operand);
 
   void SetSpillStartIndex(int start) {
     spill_start_index_ = Min(start, spill_start_index_);
   }
 
   bool ShouldBeAllocatedBefore(const LiveRange* other) const;
   bool CanCover(LifetimePosition position) const;
   bool Covers(LifetimePosition position);
   LifetimePosition FirstIntersection(LiveRange* other);
 
   // Add a new interval or a new use position to this live range.
   void EnsureInterval(LifetimePosition start,
                       LifetimePosition end,
                       Zone* zone);
   void AddUseInterval(LifetimePosition start,
                       LifetimePosition end,
                       Zone* zone);
-  void AddUsePosition(LifetimePosition pos,
-                      LOperand* operand,
-                      LOperand* hint,
-                      Zone* zone);
+  void AddUsePosition(LifetimePosition pos, InstructionOperand* operand,
+                      InstructionOperand* hint, Zone* zone);
 
   // Shorten the most recently added interval by setting a new start.
   void ShortenTo(LifetimePosition start);
 
 #ifdef DEBUG
   // True if target overlaps an existing interval.
   bool HasOverlap(UseInterval* target) const;
   void Verify() const;
 #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_phi_;
+  bool is_non_loop_phi_;
   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_;
+  InstructionOperand* current_hint_operand_;
+  InstructionOperand* spill_operand_;
   int spill_start_index_;
 
-  friend class LAllocator;  // Assigns to kind_.
+  friend class RegisterAllocator;  // Assigns to kind_.
 };
 
 
-class LAllocator BASE_EMBEDDED {
+class RegisterAllocator BASE_EMBEDDED {
  public:
-  LAllocator(int first_virtual_register, HGraph* graph);
+  explicit RegisterAllocator(InstructionSequence* code);
 
   static void TraceAlloc(const char* msg, ...);
 
-  // Checks whether the value of a given virtual register is tagged.
+  // Checks whether the value of a given virtual register is a reference.
+  // TODO(titzer): rename this to IsReference.
   bool HasTaggedValue(int virtual_register) const;
 
   // Returns the register kind required by the given virtual register.
   RegisterKind RequiredRegisterKind(int virtual_register) const;
 
-  bool Allocate(LChunk* chunk);
+  bool Allocate();
 
   const ZoneList<LiveRange*>* live_ranges() const { return &live_ranges_; }
   const Vector<LiveRange*>* fixed_live_ranges() const {
     return &fixed_live_ranges_;
   }
   const Vector<LiveRange*>* fixed_double_live_ranges() const {
     return &fixed_double_live_ranges_;
   }
 
-  LPlatformChunk* chunk() const { return chunk_; }
-  HGraph* graph() const { return graph_; }
-  Isolate* isolate() const { return graph_->isolate(); }
-  Zone* zone() { return &zone_; }
+  inline InstructionSequence* code() const { return code_; }
+
+  // This zone is for datastructures only needed during register allocation.
+  inline Zone* zone() { return &zone_; }
+
+  // This zone is for InstructionOperands and moves that live beyond register
+  // allocation.
+  inline Zone* code_zone() { return code()->zone(); }
 
   int GetVirtualRegister() {
-    if (next_virtual_register_ >= LUnallocated::kMaxVirtualRegisters) {
+    int vreg = code()->NextVirtualRegister();
+    if (vreg >= UnallocatedOperand::kMaxVirtualRegisters) {
       allocation_ok_ = false;
       // Maintain the invariant that we return something below the maximum.
       return 0;
     }
-    return next_virtual_register_++;
+    return vreg;
   }
 
   bool AllocationOk() { return allocation_ok_; }
 
-  void MarkAsOsrEntry() {
-    // There can be only one.
-    ASSERT(!has_osr_entry_);
-    // Simply set a flag to find and process instruction later.
-    has_osr_entry_ = true;
-  }
-
 #ifdef DEBUG
   void Verify() const;
 #endif
 
   BitVector* assigned_registers() {
     return assigned_registers_;
   }
   BitVector* assigned_double_registers() {
     return assigned_double_registers_;
   }
 
  private:
   void MeetRegisterConstraints();
   void ResolvePhis();
   void BuildLiveRanges();
   void AllocateGeneralRegisters();
   void AllocateDoubleRegisters();
   void ConnectRanges();
   void ResolveControlFlow();
-  void PopulatePointerMaps();
+  void PopulatePointerMaps();  // TODO(titzer): rename to PopulateReferenceMaps.
   void AllocateRegisters();
-  bool CanEagerlyResolveControlFlow(HBasicBlock* block) const;
+  bool CanEagerlyResolveControlFlow(BasicBlock* block) const;
   inline bool SafePointsAreInOrder() const;
 
   // Liveness analysis support.
   void InitializeLivenessAnalysis();
-  BitVector* ComputeLiveOut(HBasicBlock* block);
-  void AddInitialIntervals(HBasicBlock* block, BitVector* live_out);
-  void ProcessInstructions(HBasicBlock* block, BitVector* live);
-  void MeetRegisterConstraints(HBasicBlock* block);
-  void MeetConstraintsBetween(LInstruction* first,
-                              LInstruction* second,
+  BitVector* ComputeLiveOut(BasicBlock* block);
+  void AddInitialIntervals(BasicBlock* block, BitVector* live_out);
+  bool IsOutputRegisterOf(Instruction* instr, int index);
+  bool IsOutputDoubleRegisterOf(Instruction* instr, int index);
+  void ProcessInstructions(BasicBlock* block, BitVector* live);
+  void MeetRegisterConstraints(BasicBlock* block);
+  void MeetConstraintsBetween(Instruction* first,
+                              Instruction* second,
                               int gap_index);
-  void ResolvePhis(HBasicBlock* block);
+  void ResolvePhis(BasicBlock* block);
 
   // Helper methods for building intervals.
-  LOperand* AllocateFixed(LUnallocated* operand, int pos, bool is_tagged);
-  LiveRange* LiveRangeFor(LOperand* operand);
-  void Define(LifetimePosition position, LOperand* operand, LOperand* hint);
-  void Use(LifetimePosition block_start,
-           LifetimePosition position,
-           LOperand* operand,
-           LOperand* hint);
-  void AddConstraintsGapMove(int index, LOperand* from, LOperand* to);
+  InstructionOperand* AllocateFixed(UnallocatedOperand* operand, int pos,
+                                    bool is_tagged);
+  LiveRange* LiveRangeFor(InstructionOperand* operand);
+  void Define(LifetimePosition position, InstructionOperand* operand,
+              InstructionOperand* hint);
+  void Use(LifetimePosition block_start, LifetimePosition position,
+           InstructionOperand* operand, InstructionOperand* hint);
+  void AddConstraintsGapMove(int index, InstructionOperand* from,
+                             InstructionOperand* to);
 
   // Helper methods for updating the life range lists.
   void AddToActive(LiveRange* range);
   void AddToInactive(LiveRange* range);
   void AddToUnhandledSorted(LiveRange* range);
   void AddToUnhandledUnsorted(LiveRange* range);
   void SortUnhandled();
   bool UnhandledIsSorted();
   void ActiveToHandled(LiveRange* range);
   void ActiveToInactive(LiveRange* range);
   void InactiveToHandled(LiveRange* range);
   void InactiveToActive(LiveRange* range);
   void FreeSpillSlot(LiveRange* range);
-  LOperand* TryReuseSpillSlot(LiveRange* range);
+  InstructionOperand* TryReuseSpillSlot(LiveRange* range);
 
   // Helper methods for allocating registers.
   bool TryAllocateFreeReg(LiveRange* range);
   void AllocateBlockedReg(LiveRange* range);
 
   // Live range splitting helpers.
 
   // Split the given range at the given position.
   // If range starts at or after the given position then the
   // original range is returned.
@@ skipping 33 matching lines @@
   // If we are trying to spill a range inside the loop try to
   // hoist spill position out to the point just before the loop.
   LifetimePosition FindOptimalSpillingPos(LiveRange* range,
                                           LifetimePosition pos);
 
   void Spill(LiveRange* range);
   bool IsBlockBoundary(LifetimePosition pos);
 
   // Helper methods for resolving control flow.
   void ResolveControlFlow(LiveRange* range,
-                          HBasicBlock* block,
-                          HBasicBlock* pred);
+                          BasicBlock* block,
+                          BasicBlock* pred);
 
   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);
+  ParallelMove* GetConnectingParallelMove(LifetimePosition pos);
 
   // Return the block which contains give lifetime position.
-  HBasicBlock* GetBlock(LifetimePosition pos);
+  BasicBlock* GetBlock(LifetimePosition pos);
 
   // Helper methods for the fixed registers.
   int RegisterCount() const;
   static int FixedLiveRangeID(int index) { return -index - 1; }
   static int FixedDoubleLiveRangeID(int index);
   LiveRange* FixedLiveRangeFor(int index);
   LiveRange* FixedDoubleLiveRangeFor(int index);
   LiveRange* LiveRangeFor(int index);
-  HPhi* LookupPhi(LOperand* operand) const;
-  LGap* GetLastGap(HBasicBlock* block);
+  GapInstruction* GetLastGap(BasicBlock* block);
 
   const char* RegisterName(int allocation_index);
 
-  inline bool IsGapAt(int index);
-
-  inline LInstruction* InstructionAt(int index);
-
-  inline LGap* GapAt(int index);
+  inline Instruction* InstructionAt(int index) {
+    return code()->InstructionAt(index);
+  }
 
   Zone zone_;
-
-  LPlatformChunk* chunk_;
+  InstructionSequence* code_;
 
   // During liveness analysis keep a mapping from block id to live_in sets
   // for blocks already analyzed.
   ZoneList<BitVector*> live_in_sets_;
 
   // Liveness analysis results.
   ZoneList<LiveRange*> live_ranges_;
 
   // Lists of live ranges
   EmbeddedVector<LiveRange*, Register::kMaxNumAllocatableRegisters>
       fixed_live_ranges_;
   EmbeddedVector<LiveRange*, DoubleRegister::kMaxNumAllocatableRegisters>
       fixed_double_live_ranges_;
   ZoneList<LiveRange*> unhandled_live_ranges_;
   ZoneList<LiveRange*> active_live_ranges_;
   ZoneList<LiveRange*> inactive_live_ranges_;
   ZoneList<LiveRange*> reusable_slots_;
 
-  // Next virtual register number to be assigned to temporaries.
-  int next_virtual_register_;
-  int first_artificial_register_;
-  GrowableBitVector double_artificial_registers_;
-
   RegisterKind mode_;
   int num_registers_;
 
   BitVector* assigned_registers_;
   BitVector* assigned_double_registers_;
 
-  HGraph* graph_;
-
-  bool has_osr_entry_;
-
   // Indicates success or failure during register allocation.
   bool allocation_ok_;
 
 #ifdef DEBUG
   LifetimePosition allocation_finger_;
 #endif
 
-  DISALLOW_COPY_AND_ASSIGN(LAllocator);
+  DISALLOW_COPY_AND_ASSIGN(RegisterAllocator);
 };
 
 
-class LAllocatorPhase : public CompilationPhase {
+class RegisterAllocatorPhase : public CompilationPhase {
  public:
-  LAllocatorPhase(const char* name, LAllocator* allocator);
-  ~LAllocatorPhase();
+  RegisterAllocatorPhase(const char* name, RegisterAllocator* allocator);
+  ~RegisterAllocatorPhase();
 
  private:
-  LAllocator* allocator_;
+  RegisterAllocator* allocator_;
   unsigned allocator_zone_start_allocation_size_;
 
-  DISALLOW_COPY_AND_ASSIGN(LAllocatorPhase);
+  DISALLOW_COPY_AND_ASSIGN(RegisterAllocatorPhase);
 };
 
 
-} }  // namespace v8::internal
+} } }  // namespace v8::internal::compiler
 
-#endif  // V8_LITHIUM_ALLOCATOR_H_
+#endif  // V8_REGISTER_ALLOCATOR_H_