[Subzero][MIPS32] Implements variable alloca for MIPS32

src/IceTargetLoweringMIPS32.h

 //===- subzero/src/IceTargetLoweringMIPS32.h - MIPS32 lowering ---*- C++-*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 545 matching lines @@
   makeRandomRegisterPermutation(llvm::SmallVectorImpl<RegNumT> &Permutation,
                                 const SmallBitVector &ExcludeRegisters,
                                 uint64_t Salt) const override;
 
   OperandMIPS32Mem *formMemoryOperand(Operand *Ptr, Type Ty);
 
   bool UsesFramePointer = false;
   bool NeedsStackAlignment = false;
   bool MaybeLeafFunc = true;
   bool PrologEmitsFixedAllocas = false;
+  bool VariableAllocaUsed = false;
   uint32_t MaxOutArgsSizeBytes = 0;
   uint32_t TotalStackSizeBytes = 0;
   static SmallBitVector TypeToRegisterSet[RCMIPS32_NUM];
   static SmallBitVector TypeToRegisterSetUnfiltered[RCMIPS32_NUM];
   static SmallBitVector RegisterAliases[RegMIPS32::Reg_NUM];
   SmallBitVector RegsUsed;
   VarList PhysicalRegisters[IceType_NUM];
   VarList PreservedGPRs;
   static constexpr uint32_t CHAR_BITS = 8;
   static constexpr uint32_t INT32_BITS = 32;
@@ skipping 105 matching lines @@
   explicit TargetHeaderMIPS32(GlobalContext *Ctx);
 
 private:
   ~TargetHeaderMIPS32() = default;
 };
 
 } // end of namespace MIPS32
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETARGETLOWERINGMIPS32_H