Sort allocas, compute frame pointer in Cfg pass

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 31 matching lines @@
   IceString getRegName(SizeT RegNum, Type Ty) const override;
   llvm::SmallBitVector getRegisterSet(RegSetMask Include,
                                       RegSetMask Exclude) const override;
   const llvm::SmallBitVector &getRegisterSetForType(Type Ty) const override {
     return TypeToRegisterSet[Ty];
   }
   const llvm::SmallBitVector &getAliasesForRegister(SizeT Reg) const override {
     return RegisterAliases[Reg];
   }
   bool hasFramePointer() const override { return UsesFramePointer; }
+  void setHasFramePointer() override { UsesFramePointer = true; }
   SizeT getStackReg() const override { return RegMIPS32::Reg_SP; }
   SizeT getFrameOrStackReg() const override {
     return UsesFramePointer ? RegMIPS32::Reg_FP : RegMIPS32::Reg_SP;
   }
   size_t typeWidthInBytesOnStack(Type Ty) const override {
     // Round up to the next multiple of 4 bytes. In particular, i1, i8, and i16
     // are rounded up to 4 bytes.
     return (typeWidthInBytes(Ty) + 3) & ~3;
   }
+  uint32_t getStackAlignment() const override {
+    // TODO(sehr): what is the stack alignment?
+    return 1;
+  }
 
   bool shouldSplitToVariable64On32(Type Ty) const override {
     return Ty == IceType_i64;
   }
 
   // TODO(ascull): what is the best size of MIPS?
   SizeT getMinJumpTableSize() const override { return 3; }
   void emitJumpTable(const Cfg *Func,
                      const InstJumpTable *JumpTable) const override;
 
@@ skipping 203 matching lines @@
 protected:
   explicit TargetHeaderMIPS32(GlobalContext *Ctx);
 
 private:
   ~TargetHeaderMIPS32() = default;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETARGETLOWERINGMIPS32_H