bool Z80FrameLowering::restoreCalleeSavedRegisters(
MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
std::vector<CalleeSavedInfo> &CSI,
const TargetRegisterInfo *TRI) const {
const MachineFunction &MF = *MBB.getParent();
bool UseShadow = shouldUseShadow(MF);
DebugLoc DL = MBB.findDebugLoc(MI);
for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
unsigned Reg = CSI[i].getReg();
// Non-index registers can be spilled to shadow registers.
if (UseShadow && !Z80::I24RegClass.contains(Reg) &&
!Z80::I16RegClass.contains(Reg))
continue;
MachineInstrBuilder MIB;
if (Reg == Z80::AF)
MIB = BuildMI(MBB, MI, DL, TII.get(Is24Bit ? Z80::POP24AF
: Z80::POP16AF));
else
MIB = BuildMI(MBB, MI, DL, TII.get(Is24Bit ? Z80::POP24r : Z80::POP16r),
Reg);
MIB.setMIFlag(MachineInstr::FrameDestroy);
}
if (UseShadow)
shadowCalleeSavedRegisters(MBB, MI, DL, MachineInstr::FrameDestroy, CSI);
return true;
}
bool Z80FrameLowering::spillCalleeSavedRegisters(
MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
const std::vector<CalleeSavedInfo> &CSI,
const TargetRegisterInfo *TRI) const {
const MachineFunction &MF = *MBB.getParent();
const MachineRegisterInfo &MRI = MF.getRegInfo();
bool UseShadow = shouldUseShadow(MF);
DebugLoc DL = MBB.findDebugLoc(MI);
if (UseShadow)
shadowCalleeSavedRegisters(MBB, MI, DL, MachineInstr::FrameSetup, CSI);
for (unsigned i = CSI.size(); i != 0; --i) {
unsigned Reg = CSI[i - 1].getReg();
// Non-index registers can be spilled to shadow registers.
if (UseShadow && !Z80::I24RegClass.contains(Reg) &&
!Z80::I16RegClass.contains(Reg))
continue;
bool isLiveIn = MRI.isLiveIn(Reg);
if (!isLiveIn)
MBB.addLiveIn(Reg);
// Decide whether we can add a kill flag to the use.
bool CanKill = !isLiveIn;
// Check if any subregister is live-in
if (CanKill) {
for (MCRegAliasIterator AReg(Reg, TRI, false); AReg.isValid(); ++AReg) {
if (MRI.isLiveIn(*AReg)) {
CanKill = false;
break;
}
}
}
// Do not set a kill flag on values that are also marked as live-in. This
// happens with the @llvm-returnaddress intrinsic and with arguments
// passed in callee saved registers.
// Omitting the kill flags is conservatively correct even if the live-in
// is not used after all.
MachineInstrBuilder MIB;
if (Reg == Z80::AF)
MIB = BuildMI(MBB, MI, DL, TII.get(Is24Bit ? Z80::PUSH24AF
: Z80::PUSH16AF));
else
MIB = BuildMI(MBB, MI, DL, TII.get(Is24Bit ? Z80::PUSH24r : Z80::PUSH16r))
.addReg(Reg, getKillRegState(CanKill));
MIB.setMIFlag(MachineInstr::FrameSetup);
}
return true;
}
