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

// FrameIndex represent objects inside a abstract stack.
// We must replace FrameIndex with an stack/frame pointer
// direct reference.
void MipsRegisterInfo::
eliminateFrameIndex(MachineBasicBlock::iterator II, int SPAdj,
                    RegScavenger *RS) const {
  MachineInstr &MI = *II;
  MachineFunction &MF = *MI.getParent()->getParent();
  MachineFrameInfo *MFI = MF.getFrameInfo();
  MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();

  unsigned i = 0;
  while (!MI.getOperand(i).isFI()) {
    ++i;
    assert(i < MI.getNumOperands() &&
           "Instr doesn't have FrameIndex operand!");
  }

  DEBUG(errs() << "\nFunction : " << MF.getFunction()->getName() << "\n";
        errs() << "<--------->\n" << MI);

  int FrameIndex = MI.getOperand(i).getIndex();
  uint64_t stackSize = MF.getFrameInfo()->getStackSize();
  int64_t spOffset = MF.getFrameInfo()->getObjectOffset(FrameIndex);

  DEBUG(errs() << "FrameIndex : " << FrameIndex << "\n"
               << "spOffset   : " << spOffset << "\n"
               << "stackSize  : " << stackSize << "\n");

  const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
  int MinCSFI = 0;
  int MaxCSFI = -1;

  if (CSI.size()) {
    MinCSFI = CSI[0].getFrameIdx();
    MaxCSFI = CSI[CSI.size() - 1].getFrameIdx();
  }

  // The following stack frame objects are always referenced relative to $sp:
  //  1. Outgoing arguments.
  //  2. Pointer to dynamically allocated stack space.
  //  3. Locations for callee-saved registers.
  // Everything else is referenced relative to whatever register
  // getFrameRegister() returns.
  unsigned FrameReg;

  if (MipsFI->isOutArgFI(FrameIndex) || MipsFI->isDynAllocFI(FrameIndex) ||
      (FrameIndex >= MinCSFI && FrameIndex <= MaxCSFI))
    FrameReg = Subtarget.isABI_N64() ? Mips::SP_64 : Mips::SP;
  else
    FrameReg = getFrameRegister(MF);

  // Calculate final offset.
  // - There is no need to change the offset if the frame object is one of the
  //   following: an outgoing argument, pointer to a dynamically allocated
  //   stack space or a $gp restore location,
  // - If the frame object is any of the following, its offset must be adjusted
  //   by adding the size of the stack:
  //   incoming argument, callee-saved register location or local variable.
  int64_t Offset;

  if (MipsFI->isOutArgFI(FrameIndex) || MipsFI->isGPFI(FrameIndex) ||
      MipsFI->isDynAllocFI(FrameIndex))
    Offset = spOffset;
  else
    Offset = spOffset + (int64_t)stackSize;

  Offset    += MI.getOperand(i+1).getImm();

  DEBUG(errs() << "Offset     : " << Offset << "\n" << "<--------->\n");

  // If MI is not a debug value, make sure Offset fits in the 16-bit immediate
  // field.
  if (!MI.isDebugValue() && !isInt<16>(Offset)) {
    MachineBasicBlock &MBB = *MI.getParent();
    DebugLoc DL = II->getDebugLoc();
    MipsAnalyzeImmediate AnalyzeImm;
    unsigned Size = Subtarget.isABI_N64() ? 64 : 32;
    unsigned LUi = Subtarget.isABI_N64() ? Mips::LUi64 : Mips::LUi;
    unsigned ADDu = Subtarget.isABI_N64() ? Mips::DADDu : Mips::ADDu;
    unsigned ZEROReg = Subtarget.isABI_N64() ? Mips::ZERO_64 : Mips::ZERO;
    unsigned ATReg = Subtarget.isABI_N64() ? Mips::AT_64 : Mips::AT;
    const MipsAnalyzeImmediate::InstSeq &Seq =
      AnalyzeImm.Analyze(Offset, Size, true /* LastInstrIsADDiu */);
    MipsAnalyzeImmediate::InstSeq::const_iterator Inst = Seq.begin();

    // FIXME: change this when mips goes MC".
    BuildMI(MBB, II, DL, TII.get(Mips::NOAT));

    // The first instruction can be a LUi, which is different from other
    // instructions (ADDiu, ORI and SLL) in that it does not have a register
    // operand.
    if (Inst->Opc == LUi)
      BuildMI(MBB, II, DL, TII.get(LUi), ATReg)
        .addImm(SignExtend64<16>(Inst->ImmOpnd));
    else
      BuildMI(MBB, II, DL, TII.get(Inst->Opc), ATReg).addReg(ZEROReg)
        .addImm(SignExtend64<16>(Inst->ImmOpnd));

    // Build the remaining instructions in Seq except for the last one.
//.........这里部分代码省略.........