Subzero: Merge SpillVariable functionality directly into Variable.

src/IceTargetLoweringX8664Traits.h

 //===- subzero/src/IceTargetLoweringX8664Traits.h - x86-64 traits -*- C++ -*-=//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 960 matching lines @@
       assert(Var->getType() == IceType_f64);
       Vars = Func->allocateArrayOf<Variable *>(1);
       Vars[0] = Var;
       NumVars = 1;
     }
 
     Variable *Var;
     Portion Part;
   };
 
-  /// SpillVariable decorates a Variable by linking it to another Variable. When
-  /// stack frame offsets are computed, the SpillVariable is given a distinct
-  /// stack slot only if its linked Variable has a register. If the linked
-  /// Variable has a stack slot, then the Variable and SpillVariable share that
-  /// slot.
-  class SpillVariable : public Variable {
-    SpillVariable() = delete;
-    SpillVariable(const SpillVariable &) = delete;
-    SpillVariable &operator=(const SpillVariable &) = delete;
-
-  public:
-    static SpillVariable *create(Cfg *Func, Type Ty, SizeT Index) {
-      return new (Func->allocate<SpillVariable>())
-          SpillVariable(Func, Ty, Index);
-    }
-    constexpr static auto SpillVariableKind =
-        static_cast<OperandKind>(kVariable_Target);
-    static bool classof(const Operand *Operand) {
-      return Operand->getKind() == SpillVariableKind;
-    }
-    void setLinkedTo(Variable *Var) { LinkedTo = Var; }
-    Variable *getLinkedTo() const { return LinkedTo; }
-    // Inherit dump() and emit() from Variable.
-
-  private:
-    SpillVariable(const Cfg *Func, Type Ty, SizeT Index)
-        : Variable(Func, SpillVariableKind, Ty, Index), LinkedTo(nullptr) {}
-    Variable *LinkedTo;
-  };
-
   // Note: The following data structures are defined in IceInstX8664.cpp.
 
   static const struct InstBrAttributesType {
     Cond::BrCond Opposite;
     const char *DisplayString;
     const char *EmitString;
   } InstBrAttributes[];
 
   static const struct InstCmppsAttributesType {
     const char *EmitString;
@@ skipping 10 matching lines @@
     const char *FldString;    // s, l, or <blank>
   } TypeAttributes[];
 };
 
 using Traits = ::Ice::X8664::TargetX8664Traits;
 } // end of namespace X8664
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETARGETLOWERINGX8664TRAITS_H