C++ MipsFunctionInfo::getRAStackOffset方法代码示例

void MipsFrameInfo::emitPrologue(MachineFunction &MF) const {
  MachineBasicBlock &MBB   = MF.front();
  MachineFrameInfo *MFI    = MF.getFrameInfo();
  MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
  const MipsRegisterInfo *RegInfo =
    static_cast<const MipsRegisterInfo*>(MF.getTarget().getRegisterInfo());
  const MipsInstrInfo &TII =
    *static_cast<const MipsInstrInfo*>(MF.getTarget().getInstrInfo());
  MachineBasicBlock::iterator MBBI = MBB.begin();
  DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
  bool isPIC = (MF.getTarget().getRelocationModel() == Reloc::PIC_);

  // Get the right frame order for Mips.
  adjustMipsStackFrame(MF);

  // Get the number of bytes to allocate from the FrameInfo.
  unsigned StackSize = MFI->getStackSize();

  // No need to allocate space on the stack.
  if (StackSize == 0 && !MFI->adjustsStack()) return;

  int FPOffset = MipsFI->getFPStackOffset();
  int RAOffset = MipsFI->getRAStackOffset();

  BuildMI(MBB, MBBI, dl, TII.get(Mips::NOREORDER));

  // TODO: check need from GP here.
  if (isPIC && STI.isABI_O32())
    BuildMI(MBB, MBBI, dl, TII.get(Mips::CPLOAD))
      .addReg(RegInfo->getPICCallReg());
  BuildMI(MBB, MBBI, dl, TII.get(Mips::NOMACRO));

  // Adjust stack : addi sp, sp, (-imm)
  BuildMI(MBB, MBBI, dl, TII.get(Mips::ADDiu), Mips::SP)
      .addReg(Mips::SP).addImm(-StackSize);

  // Save the return address only if the function isnt a leaf one.
  // sw  $ra, stack_loc($sp)
  if (MFI->adjustsStack()) {
    BuildMI(MBB, MBBI, dl, TII.get(Mips::SW))
        .addReg(Mips::RA).addImm(RAOffset).addReg(Mips::SP);
  }

  // if framepointer enabled, save it and set it
  // to point to the stack pointer
  if (hasFP(MF)) {
    // sw  $fp,stack_loc($sp)
    BuildMI(MBB, MBBI, dl, TII.get(Mips::SW))
      .addReg(Mips::FP).addImm(FPOffset).addReg(Mips::SP);

    // move $fp, $sp
    BuildMI(MBB, MBBI, dl, TII.get(Mips::ADDu), Mips::FP)
      .addReg(Mips::SP).addReg(Mips::ZERO);
  }

  // Restore GP from the saved stack location
  if (MipsFI->needGPSaveRestore())
    BuildMI(MBB, MBBI, dl, TII.get(Mips::CPRESTORE))
      .addImm(MipsFI->getGPStackOffset());
}

void MipsFrameInfo::emitEpilogue(MachineFunction &MF,
                                 MachineBasicBlock &MBB) const {
  MachineBasicBlock::iterator MBBI = prior(MBB.end());
  MachineFrameInfo *MFI            = MF.getFrameInfo();
  MipsFunctionInfo *MipsFI         = MF.getInfo<MipsFunctionInfo>();
  const MipsInstrInfo &TII =
    *static_cast<const MipsInstrInfo*>(MF.getTarget().getInstrInfo());
  DebugLoc dl = MBBI->getDebugLoc();

  // Get the number of bytes from FrameInfo
  int NumBytes = (int) MFI->getStackSize();

  // Get the FI's where RA and FP are saved.
  int FPOffset = MipsFI->getFPStackOffset();
  int RAOffset = MipsFI->getRAStackOffset();

  // if framepointer enabled, restore it and restore the
  // stack pointer
  if (hasFP(MF)) {
    // move $sp, $fp
    BuildMI(MBB, MBBI, dl, TII.get(Mips::ADDu), Mips::SP)
      .addReg(Mips::FP).addReg(Mips::ZERO);

    // lw  $fp,stack_loc($sp)
    BuildMI(MBB, MBBI, dl, TII.get(Mips::LW), Mips::FP)
      .addImm(FPOffset).addReg(Mips::SP);
  }

  // Restore the return address only if the function isnt a leaf one.
  // lw  $ra, stack_loc($sp)
  if (MFI->adjustsStack()) {
    BuildMI(MBB, MBBI, dl, TII.get(Mips::LW), Mips::RA)
      .addImm(RAOffset).addReg(Mips::SP);
  }

  // adjust stack  : insert addi sp, sp, (imm)
  if (NumBytes) {
    BuildMI(MBB, MBBI, dl, TII.get(Mips::ADDiu), Mips::SP)
      .addReg(Mips::SP).addImm(NumBytes);
  }
}

void MipsFrameLowering::emitEpilogue(MachineFunction &MF,
                                 MachineBasicBlock &MBB) const {
  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
  MachineFrameInfo *MFI            = MF.getFrameInfo();
  MipsFunctionInfo *MipsFI         = MF.getInfo<MipsFunctionInfo>();
  const MipsInstrInfo &TII =
    *static_cast<const MipsInstrInfo*>(MF.getTarget().getInstrInfo());
  DebugLoc dl = MBBI->getDebugLoc();

  // Get the number of bytes from FrameInfo
  int NumBytes = (int) MFI->getStackSize();

  // Get the FI's where RA and FP are saved.
  int FPOffset = MipsFI->getFPStackOffset();
  int RAOffset = MipsFI->getRAStackOffset();

  unsigned NewReg = 0;
  int NewImm = 0;
  bool ATUsed = false;

  // if framepointer enabled, restore it and restore the
  // stack pointer
  if (hasFP(MF)) {
    // move $sp, $fp
    BuildMI(MBB, MBBI, dl, TII.get(Mips::ADDu), Mips::SP)
      .addReg(Mips::FP).addReg(Mips::ZERO);

    // lw  $fp,stack_loc($sp)
    ATUsed = expandRegLargeImmPair(Mips::SP, FPOffset, NewReg, NewImm, MBB,
                                                MBBI);
    BuildMI(MBB, MBBI, dl, TII.get(Mips::LW), Mips::FP)
      .addImm(NewImm).addReg(NewReg);

    // FIXME: change this when mips goes MC".
    if (ATUsed)
      BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
  }

  // Restore the return address only if the function isnt a leaf one.
  // lw  $ra, stack_loc($sp)
  if (MFI->adjustsStack()) {
    expandRegLargeImmPair(Mips::SP, RAOffset, NewReg, NewImm, MBB, MBBI);
    BuildMI(MBB, MBBI, dl, TII.get(Mips::LW), Mips::RA)
      .addImm(NewImm).addReg(NewReg);

    // FIXME: change this when mips goes MC".
    if (ATUsed)
      BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
  }

  // adjust stack  : insert addi sp, sp, (imm)
  if (NumBytes) {
    expandRegLargeImmPair(Mips::SP, NumBytes, NewReg, NewImm, MBB, MBBI);
    BuildMI(MBB, MBBI, dl, TII.get(Mips::ADDiu), Mips::SP)
      .addReg(NewReg).addImm(NewImm);

    // FIXME: change this when mips goes MC".
    if (ATUsed)
      BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
  }
}