[Turbofan] Add the concept of aliasing to RegisterConfiguration.

src/compiler/register-allocator.h

 // 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_REGISTER_ALLOCATOR_H_
 #define V8_REGISTER_ALLOCATOR_H_
 
 #include "src/compiler/instruction.h"
 #include "src/ostreams.h"
 #include "src/register-configuration.h"
@@ skipping 660 matching lines @@
 std::ostream& operator<<(std::ostream& os,
                          const PrintableLiveRange& printable_range);
 
 
 class SpillRange final : public ZoneObject {
  public:
   static const int kUnassignedSlot = -1;
   SpillRange(TopLevelLiveRange* range, Zone* zone);
 
   UseInterval* interval() const { return use_interval_; }
-  // Currently, only 4 or 8 byte slots are supported.
-  int ByteWidth() const;

[bbudge, 2016/06/21 23:09:35]

This is redundant, as a byte_width() getter is defined below.

[Mircea Trofin, 2016/06/22 06:07:34]

Acknowledged.

+
   bool IsEmpty() const { return live_ranges_.empty(); }
   bool TryMerge(SpillRange* other);
   bool HasSlot() const { return assigned_slot_ != kUnassignedSlot; }
 
   void set_assigned_slot(int index) {
     DCHECK_EQ(kUnassignedSlot, assigned_slot_);
     assigned_slot_ = index;
   }
   int assigned_slot() {
     DCHECK_NE(kUnassignedSlot, assigned_slot_);
@@ skipping 68 matching lines @@
   const ZoneVector<TopLevelLiveRange*>& live_ranges() const {
     return live_ranges_;
   }
   ZoneVector<TopLevelLiveRange*>& live_ranges() { return live_ranges_; }
   const ZoneVector<TopLevelLiveRange*>& fixed_live_ranges() const {
     return fixed_live_ranges_;
   }
   ZoneVector<TopLevelLiveRange*>& fixed_live_ranges() {
     return fixed_live_ranges_;
   }
+  ZoneVector<TopLevelLiveRange*>& fixed_float_live_ranges() {
+    return fixed_float_live_ranges_;
+  }
+  const ZoneVector<TopLevelLiveRange*>& fixed_float_live_ranges() const {
+    return fixed_float_live_ranges_;
+  }
   ZoneVector<TopLevelLiveRange*>& fixed_double_live_ranges() {
     return fixed_double_live_ranges_;
   }
   const ZoneVector<TopLevelLiveRange*>& fixed_double_live_ranges() const {
     return fixed_double_live_ranges_;
   }
   ZoneVector<BitVector*>& live_in_sets() { return live_in_sets_; }
   ZoneVector<BitVector*>& live_out_sets() { return live_out_sets_; }
   ZoneVector<SpillRange*>& spill_ranges() { return spill_ranges_; }
   DelayedReferences& delayed_references() { return delayed_references_; }
   InstructionSequence* code() const { return code_; }
-  // This zone is for datastructures only needed during register allocation
+  // This zone is for data structures only needed during register allocation
   // phases.
   Zone* allocation_zone() const { return allocation_zone_; }
   // This zone is for InstructionOperands and moves that live beyond register
   // allocation.
   Zone* code_zone() const { return code()->zone(); }
   Frame* frame() const { return frame_; }
   const char* debug_name() const { return debug_name_; }
   const RegisterConfiguration* config() const { return config_; }
 
   MachineRepresentation RepresentationFor(int virtual_register);
@@ skipping 10 matching lines @@
                            const InstructionOperand& from,
                            const InstructionOperand& to);
 
   bool IsReference(TopLevelLiveRange* top_range) const {
     return code()->IsReference(top_range->vreg());
   }
 
   bool ExistsUseWithoutDefinition();
   bool RangesDefinedInDeferredStayInDeferred();
 
-  void MarkAllocated(RegisterKind kind, int index);
+  void MarkAllocated(MachineRepresentation rep, int index);
 
   PhiMapValue* InitializePhiMap(const InstructionBlock* block,
                                 PhiInstruction* phi);
   PhiMapValue* GetPhiMapValueFor(TopLevelLiveRange* top_range);
   PhiMapValue* GetPhiMapValueFor(int virtual_register);
   bool IsBlockBoundary(LifetimePosition pos) const;
 
   RangesWithPreassignedSlots& preassigned_slot_ranges() {
     return preassigned_slot_ranges_;
   }
 
  private:
   int GetNextLiveRangeId();
 
   Zone* const allocation_zone_;
   Frame* const frame_;
   InstructionSequence* const code_;
   const char* const debug_name_;
   const RegisterConfiguration* const config_;
   PhiMap phi_map_;
   ZoneVector<BitVector*> live_in_sets_;
   ZoneVector<BitVector*> live_out_sets_;
   ZoneVector<TopLevelLiveRange*> live_ranges_;
   ZoneVector<TopLevelLiveRange*> fixed_live_ranges_;
+  ZoneVector<TopLevelLiveRange*> fixed_float_live_ranges_;
   ZoneVector<TopLevelLiveRange*> fixed_double_live_ranges_;
   ZoneVector<SpillRange*> spill_ranges_;
   DelayedReferences delayed_references_;
   BitVector* assigned_registers_;
   BitVector* assigned_double_registers_;
   int virtual_register_count_;
   RangesWithPreassignedSlots preassigned_slot_ranges_;
 
   DISALLOW_COPY_AND_ASSIGN(RegisterAllocationData);
 };
@@ skipping 56 matching lines @@
                                           const TopLevelLiveRange* range) const;
   bool NextIntervalStartsInDifferentBlocks(const UseInterval* interval) const;
 
   // Liveness analysis support.
   void AddInitialIntervals(const InstructionBlock* block, BitVector* live_out);
   void ProcessInstructions(const InstructionBlock* block, BitVector* live);
   void ProcessPhis(const InstructionBlock* block, BitVector* live);
   void ProcessLoopHeader(const InstructionBlock* block, BitVector* live);
 
   static int FixedLiveRangeID(int index) { return -index - 1; }
-  int FixedDoubleLiveRangeID(int index);
+  int FixedFPLiveRangeID(int index, MachineRepresentation rep);
   TopLevelLiveRange* FixedLiveRangeFor(int index);
-  TopLevelLiveRange* FixedDoubleLiveRangeFor(int index);
+  TopLevelLiveRange* FixedFPLiveRangeFor(int index, MachineRepresentation rep);
 
   void MapPhiHint(InstructionOperand* operand, UsePosition* use_pos);
   void ResolvePhiHint(InstructionOperand* operand, UsePosition* use_pos);
 
   UsePosition* NewUsePosition(LifetimePosition pos, InstructionOperand* operand,
                               void* hint, UsePositionHintType hint_type);
   UsePosition* NewUsePosition(LifetimePosition pos) {
     return NewUsePosition(pos, nullptr, nullptr, UsePositionHintType::kNone);
   }
   TopLevelLiveRange* LiveRangeFor(InstructionOperand* operand);
@@ skipping 13 matching lines @@
 
   RegisterAllocationData* const data_;
   ZoneMap<InstructionOperand*, UsePosition*> phi_hints_;
 
   DISALLOW_COPY_AND_ASSIGN(LiveRangeBuilder);
 };
 
 
 class RegisterAllocator : public ZoneObject {
  public:
-  explicit RegisterAllocator(RegisterAllocationData* data, RegisterKind kind);
+  RegisterAllocator(RegisterAllocationData* data, RegisterKind kind);
 
  protected:
   RegisterAllocationData* data() const { return data_; }
   InstructionSequence* code() const { return data()->code(); }
   RegisterKind mode() const { return mode_; }
   int num_registers() const { return num_registers_; }
   int num_allocatable_registers() const { return num_allocatable_registers_; }
-  int allocatable_register_code(int allocatable_index) const {
-    return allocatable_register_codes_[allocatable_index];
+  const int* allocatable_register_codes() const {
+    return allocatable_register_codes_;
   }
+  bool no_combining() const { return no_combining_; }

[Mircea Trofin, 2016/06/22 06:07:34]

could you add a comment as to what this represents? Should it be no_aliasing
rather?

[bbudge, 2016/06/22 20:16:04]

Done.

[Mircea Trofin, 2016/06/22 21:37:37]

Where?

[bbudge, 2016/06/22 21:51:13]

See the next revision. As for your question, I considered no_aliasing() but
decided that since all platforms have aliasing (OVERLAP for Intel, COMBINE for
ARM), that this was preferable. Note that no_combine() is always true when
allocating general regs.

 
   // TODO(mtrofin): explain why splitting in gap START is always OK.
   LifetimePosition GetSplitPositionForInstruction(const LiveRange* range,
                                                   int instruction_index);
 
   Zone* allocation_zone() const { return data()->allocation_zone(); }
 
   // Find the optimal split for ranges defined by a memory operand, e.g.
   // constants or function parameters passed on the stack.
   void SplitAndSpillRangesDefinedByMemoryOperand(bool operands_only);
@@ skipping 31 matching lines @@
   const ZoneVector<TopLevelLiveRange*>& GetFixedRegisters() const;
   const char* RegisterName(int allocation_index) const;
 
  private:
   RegisterAllocationData* const data_;
   const RegisterKind mode_;
   const int num_registers_;
   int num_allocatable_registers_;
   const int* allocatable_register_codes_;
 
+ private:
+  bool no_combining_;
+
   DISALLOW_COPY_AND_ASSIGN(RegisterAllocator);
 };
 
 
 class LinearScanAllocator final : public RegisterAllocator {
  public:
   LinearScanAllocator(RegisterAllocationData* data, RegisterKind kind,
                       Zone* local_zone);
 
   // Phase 4: compute register assignments.
@@ skipping 145 matching lines @@
   RegisterAllocationData* const data_;
 
   DISALLOW_COPY_AND_ASSIGN(LiveRangeConnector);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_REGISTER_ALLOCATOR_H_