lib/Target/Mips/MipsMachineFunction.h

//===-- MipsMachineFunctionInfo.h - Private data used for Mips ----*- C++ -*-=//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares the Mips specific subclass of MachineFunctionInfo.
//
//===----------------------------------------------------------------------===//

#ifndef MIPS_MACHINE_FUNCTION_INFO_H
#define MIPS_MACHINE_FUNCTION_INFO_H

#include <utility>
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/VectorExtras.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFrameInfo.h"

namespace llvm {

/// MipsFunctionInfo - This class is derived from MachineFunction private
/// Mips target-specific information for each MachineFunction.
class MipsFunctionInfo : public MachineFunctionInfo {

private:
  MachineFunction& MF;
  /// SRetReturnReg - Some subtargets require that sret lowering includes
  /// returning the value of the returned struct in a register. This field
  /// holds the virtual register into which the sret argument is passed.
  unsigned SRetReturnReg;

  /// GlobalBaseReg - keeps track of the virtual register initialized for
  /// use as the global base register. This is used for PIC in some PIC
  /// relocation models.
  unsigned GlobalBaseReg;

  /// VarArgsFrameIndex - FrameIndex for start of varargs area.
  int VarArgsFrameIndex;

  // Range of frame object indices.
  // InArgFIRange: Range of indices of all frame objects created during call to
  //               LowerFormalArguments.
  // OutArgFIRange: Range of indices of all frame objects created during call to
  //                LowerCall except for the frame object for restoring $gp. 
  std::pair<int, int> InArgFIRange, OutArgFIRange;
  int GPFI; // Index of the frame object for restoring $gp 
  mutable int DynAllocFI; // Frame index of dynamically allocated stack area.   
  unsigned MaxCallFrameSize;

public:
  MipsFunctionInfo(MachineFunction& MF)
  : MF(MF), SRetReturnReg(0), GlobalBaseReg(0),
    VarArgsFrameIndex(0), InArgFIRange(std::make_pair(-1, 0)),
    OutArgFIRange(std::make_pair(-1, 0)), GPFI(0), DynAllocFI(0),
    MaxCallFrameSize(0)
  {}

  bool isInArgFI(int FI) const {
    return FI <= InArgFIRange.first && FI >= InArgFIRange.second;
  }
  void setLastInArgFI(int FI) { InArgFIRange.second = FI; }

  bool isOutArgFI(int FI) const { 
    return FI <= OutArgFIRange.first && FI >= OutArgFIRange.second;
  }
  void extendOutArgFIRange(int FirstFI, int LastFI) {
    if (!OutArgFIRange.second)
      // this must be the first time this function was called.
      OutArgFIRange.first = FirstFI;
    OutArgFIRange.second = LastFI;
  }

  int getGPFI() const { return GPFI; }
  void setGPFI(int FI) { GPFI = FI; }
  bool needGPSaveRestore() const { return getGPFI(); }
  bool isGPFI(int FI) const { return GPFI && GPFI == FI; }

  // The first call to this function creates a frame object for dynamically
  // allocated stack area.
  int getDynAllocFI() const {
    if (!DynAllocFI)
      DynAllocFI = MF.getFrameInfo()->CreateFixedObject(4, 0, true);

    return DynAllocFI;
  }
  bool isDynAllocFI(int FI) const { return DynAllocFI && DynAllocFI == FI; }

  unsigned getSRetReturnReg() const { return SRetReturnReg; }
  void setSRetReturnReg(unsigned Reg) { SRetReturnReg = Reg; }

  unsigned getGlobalBaseReg() const { return GlobalBaseReg; }
  void setGlobalBaseReg(unsigned Reg) { GlobalBaseReg = Reg; }

  int getVarArgsFrameIndex() const { return VarArgsFrameIndex; }
  void setVarArgsFrameIndex(int Index) { VarArgsFrameIndex = Index; }

  unsigned getMaxCallFrameSize() const { return MaxCallFrameSize; }
  void setMaxCallFrameSize(unsigned S) { MaxCallFrameSize = S; }
};

} // end of namespace llvm

#endif // MIPS_MACHINE_FUNCTION_INFO_H