ARM: Add a postRA pass to legalize stack offsets. Greedy approach (reserve IP).

src/IceOperand.h

 //===- subzero/src/IceOperand.h - High-level operands -----------*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 485 matching lines @@
   /// Used primarily for syntactic correctness of textual assembly
   /// emission.  Note that only basic information is copied, in
   /// particular not IsArgument, IsImplicitArgument, IgnoreLiveness,
   /// RegNumTmp, Weight, Live, LoVar, HiVar, VarsReal.
   Variable *asType(Type Ty);
 
   void emit(const Cfg *Func) const override;
   using Operand::dump;
   void dump(const Cfg *Func, Ostream &Str) const override;
 
+  /// Return reg num of base register, if different from stack/frame register.
+  virtual int32_t getBaseRegNum() const { return NoRegister; }
+
   static bool classof(const Operand *Operand) {
     OperandKind Kind = Operand->getKind();
     return Kind >= kVariable && Kind <= kVariable_Num;
   }
 
 protected:
   Variable(OperandKind K, Type Ty, SizeT Index)
       : Operand(K, Ty), Number(Index) {
     Vars = VarsReal;
     Vars[0] = this;
@@ skipping 134 matching lines @@
 private:
   const Cfg *Func;
   MetadataKind Kind;
   std::vector<VariableTracking> Metadata;
   const static InstDefList NoDefinitions;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEOPERAND_H