C++ XCoreFunctionInfo::hasEHSpillSlot方法代码示例

//.........这里部分代码省略.........

  const AttributeSet &PAL = MF.getFunction()->getAttributes();
  if (PAL.hasAttrSomewhere(Attribute::Nest))
    BuildMI(MBB, MBBI, dl, TII.get(XCore::LDWSP_ru6), XCore::R11).addImm(0);
    // FIX: Needs addMemOperand() but can't use getFixedStack() or getStack().

  // Work out frame sizes.
  // We will adjust the SP in stages towards the final FrameSize.
  assert(MFI->getStackSize()%4 == 0 && "Misaligned frame size");
  const int FrameSize = MFI->getStackSize() / 4;
  int Adjusted = 0;

  bool saveLR = XFI->hasLRSpillSlot();
  bool UseENTSP = saveLR && FrameSize
                  && (MFI->getObjectOffset(XFI->getLRSpillSlot()) == 0);
  if (UseENTSP)
    saveLR = false;
  bool FP = hasFP(MF);
  bool emitFrameMoves = XCoreRegisterInfo::needsFrameMoves(MF);

  if (UseENTSP) {
    // Allocate space on the stack at the same time as saving LR.
    Adjusted = (FrameSize > MaxImmU16) ? MaxImmU16 : FrameSize;
    int Opcode = isImmU6(Adjusted) ? XCore::ENTSP_u6 : XCore::ENTSP_lu6;
    MBB.addLiveIn(XCore::LR);
    MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(Opcode));
    MIB.addImm(Adjusted);
    MIB->addRegisterKilled(XCore::LR, MF.getSubtarget().getRegisterInfo(),
                           true);
    if (emitFrameMoves) {
      EmitDefCfaOffset(MBB, MBBI, dl, TII, MMI, Adjusted*4);
      unsigned DRegNum = MRI->getDwarfRegNum(XCore::LR, true);
      EmitCfiOffset(MBB, MBBI, dl, TII, MMI, DRegNum, 0);
    }
  }

  // If necessary, save LR and FP to the stack, as we EXTSP.
  SmallVector<StackSlotInfo,2> SpillList;
  GetSpillList(SpillList, MFI, XFI, saveLR, FP);
  // We want the nearest (negative) offsets first, so reverse list.
  std::reverse(SpillList.begin(), SpillList.end());
  for (unsigned i = 0, e = SpillList.size(); i != e; ++i) {
    assert(SpillList[i].Offset % 4 == 0 && "Misaligned stack offset");
    assert(SpillList[i].Offset <= 0 && "Unexpected positive stack offset");
    int OffsetFromTop = - SpillList[i].Offset/4;
    IfNeededExtSP(MBB, MBBI, dl, TII, MMI, OffsetFromTop, Adjusted, FrameSize,
                  emitFrameMoves);
    int Offset = Adjusted - OffsetFromTop;
    int Opcode = isImmU6(Offset) ? XCore::STWSP_ru6 : XCore::STWSP_lru6;
    MBB.addLiveIn(SpillList[i].Reg);
    BuildMI(MBB, MBBI, dl, TII.get(Opcode))
      .addReg(SpillList[i].Reg, RegState::Kill)
      .addImm(Offset)
      .addMemOperand(getFrameIndexMMO(MBB, SpillList[i].FI,
                                      MachineMemOperand::MOStore));
    if (emitFrameMoves) {
      unsigned DRegNum = MRI->getDwarfRegNum(SpillList[i].Reg, true);
      EmitCfiOffset(MBB, MBBI, dl, TII, MMI, DRegNum, SpillList[i].Offset);
    }
  }

  // Complete any remaining Stack adjustment.
  IfNeededExtSP(MBB, MBBI, dl, TII, MMI, FrameSize, Adjusted, FrameSize,
                emitFrameMoves);
  assert(Adjusted==FrameSize && "IfNeededExtSP has not completed adjustment");

  if (FP) {
    // Set the FP from the SP.
    BuildMI(MBB, MBBI, dl, TII.get(XCore::LDAWSP_ru6), FramePtr).addImm(0);
    if (emitFrameMoves)
      EmitDefCfaRegister(MBB, MBBI, dl, TII, MMI,
                         MRI->getDwarfRegNum(FramePtr, true));
  }

  if (emitFrameMoves) {
    // Frame moves for callee saved.
    for (const auto &SpillLabel : XFI->getSpillLabels()) {
      MachineBasicBlock::iterator Pos = SpillLabel.first;
      ++Pos;
      const CalleeSavedInfo &CSI = SpillLabel.second;
      int Offset = MFI->getObjectOffset(CSI.getFrameIdx());
      unsigned DRegNum = MRI->getDwarfRegNum(CSI.getReg(), true);
      EmitCfiOffset(MBB, Pos, dl, TII, MMI, DRegNum, Offset);
    }
    if (XFI->hasEHSpillSlot()) {
      // The unwinder requires stack slot & CFI offsets for the exception info.
      // We do not save/spill these registers.
      SmallVector<StackSlotInfo,2> SpillList;
      GetEHSpillList(SpillList, MFI, XFI,
                     MF.getSubtarget().getTargetLowering());
      assert(SpillList.size()==2 && "Unexpected SpillList size");
      EmitCfiOffset(MBB, MBBI, dl, TII, MMI,
                    MRI->getDwarfRegNum(SpillList[0].Reg, true),
                    SpillList[0].Offset);
      EmitCfiOffset(MBB, MBBI, dl, TII, MMI,
                    MRI->getDwarfRegNum(SpillList[1].Reg, true),
                    SpillList[1].Offset);
    }
  }
}