bool SystemZFrameLowering::
restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
const std::vector<CalleeSavedInfo> &CSI,
const TargetRegisterInfo *TRI) const {
if (CSI.empty())
return false;
MachineFunction &MF = *MBB.getParent();
const TargetInstrInfo *TII = MF.getTarget().getInstrInfo();
SystemZMachineFunctionInfo *ZFI = MF.getInfo<SystemZMachineFunctionInfo>();
bool HasFP = hasFP(MF);
DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
// Restore FPRs in the normal TargetInstrInfo way.
for (unsigned I = 0, E = CSI.size(); I != E; ++I) {
unsigned Reg = CSI[I].getReg();
if (SystemZ::FP64BitRegClass.contains(Reg))
TII->loadRegFromStackSlot(MBB, MBBI, Reg, CSI[I].getFrameIdx(),
&SystemZ::FP64BitRegClass, TRI);
}
// Restore call-saved GPRs (but not call-clobbered varargs, which at
// this point might hold return values).
unsigned LowGPR = ZFI->getLowSavedGPR();
unsigned HighGPR = ZFI->getHighSavedGPR();
unsigned StartOffset = RegSpillOffsets[LowGPR];
if (LowGPR) {
// If we saved any of %r2-%r5 as varargs, we should also be saving
// and restoring %r6. If we're saving %r6 or above, we should be
// restoring it too.
assert(LowGPR != HighGPR && "Should be loading %r15 and something else");
// Build an LMG instruction.
MachineInstrBuilder MIB = BuildMI(MBB, MBBI, DL, TII->get(SystemZ::LMG));
// Add the explicit register operands.
MIB.addReg(LowGPR, RegState::Define);
MIB.addReg(HighGPR, RegState::Define);
// Add the address.
MIB.addReg(HasFP ? SystemZ::R11D : SystemZ::R15D);
MIB.addImm(StartOffset);
// Do a second scan adding regs as being defined by instruction
for (unsigned I = 0, E = CSI.size(); I != E; ++I) {
unsigned Reg = CSI[I].getReg();
if (Reg != LowGPR && Reg != HighGPR)
MIB.addReg(Reg, RegState::ImplicitDefine);
}
}
return true;
}
void SystemZFrameLowering::emitEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
const SystemZInstrInfo *ZII =
static_cast<const SystemZInstrInfo*>(MF.getTarget().getInstrInfo());
SystemZMachineFunctionInfo *ZFI = MF.getInfo<SystemZMachineFunctionInfo>();
// Skip the return instruction.
assert(MBBI->getOpcode() == SystemZ::RET &&
"Can only insert epilogue into returning blocks");
uint64_t StackSize = getAllocatedStackSize(MF);
if (ZFI->getLowSavedGPR()) {
--MBBI;
unsigned Opcode = MBBI->getOpcode();
if (Opcode != SystemZ::LMG)
llvm_unreachable("Expected to see callee-save register restore code");
unsigned AddrOpNo = 2;
DebugLoc DL = MBBI->getDebugLoc();
uint64_t Offset = StackSize + MBBI->getOperand(AddrOpNo + 1).getImm();
unsigned NewOpcode = ZII->getOpcodeForOffset(Opcode, Offset);
// If the offset is too large, use the largest stack-aligned offset
// and add the rest to the base register (the stack or frame pointer).
if (!NewOpcode) {
uint64_t NumBytes = Offset - 0x7fff8;
emitIncrement(MBB, MBBI, DL, MBBI->getOperand(AddrOpNo).getReg(),
NumBytes, ZII);
Offset -= NumBytes;
NewOpcode = ZII->getOpcodeForOffset(Opcode, Offset);
assert(NewOpcode && "No restore instruction available");
}
MBBI->setDesc(ZII->get(NewOpcode));
MBBI->getOperand(AddrOpNo + 1).ChangeToImmediate(Offset);
} else if (StackSize) {
DebugLoc DL = MBBI->getDebugLoc();
emitIncrement(MBB, MBBI, DL, SystemZ::R15D, StackSize, ZII);
}
}
void SystemZFrameLowering::emitPrologue(MachineFunction &MF) const {
MachineBasicBlock &MBB = MF.front();
MachineFrameInfo *MFFrame = MF.getFrameInfo();
auto *ZII =
static_cast<const SystemZInstrInfo*>(MF.getTarget().getInstrInfo());
SystemZMachineFunctionInfo *ZFI = MF.getInfo<SystemZMachineFunctionInfo>();
MachineBasicBlock::iterator MBBI = MBB.begin();
MachineModuleInfo &MMI = MF.getMMI();
const MCRegisterInfo *MRI = MMI.getContext().getRegisterInfo();
const std::vector<CalleeSavedInfo> &CSI = MFFrame->getCalleeSavedInfo();
bool HasFP = hasFP(MF);
DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
// The current offset of the stack pointer from the CFA.
int64_t SPOffsetFromCFA = -SystemZMC::CFAOffsetFromInitialSP;
if (ZFI->getLowSavedGPR()) {
// Skip over the GPR saves.
if (MBBI != MBB.end() && MBBI->getOpcode() == SystemZ::STMG)
++MBBI;
else
llvm_unreachable("Couldn't skip over GPR saves");
// Add CFI for the GPR saves.
for (auto &Save : CSI) {
unsigned Reg = Save.getReg();
if (SystemZ::GR64BitRegClass.contains(Reg)) {
int64_t Offset = SPOffsetFromCFA + RegSpillOffsets[Reg];
unsigned CFIIndex = MMI.addFrameInst(MCCFIInstruction::createOffset(
nullptr, MRI->getDwarfRegNum(Reg, true), Offset));
BuildMI(MBB, MBBI, DL, ZII->get(TargetOpcode::CFI_INSTRUCTION))
.addCFIIndex(CFIIndex);
}
}
}
uint64_t StackSize = getAllocatedStackSize(MF);
if (StackSize) {
// Allocate StackSize bytes.
int64_t Delta = -int64_t(StackSize);
emitIncrement(MBB, MBBI, DL, SystemZ::R15D, Delta, ZII);
// Add CFI for the allocation.
unsigned CFIIndex = MMI.addFrameInst(
MCCFIInstruction::createDefCfaOffset(nullptr, SPOffsetFromCFA + Delta));
BuildMI(MBB, MBBI, DL, ZII->get(TargetOpcode::CFI_INSTRUCTION))
.addCFIIndex(CFIIndex);
SPOffsetFromCFA += Delta;
}
if (HasFP) {
// Copy the base of the frame to R11.
BuildMI(MBB, MBBI, DL, ZII->get(SystemZ::LGR), SystemZ::R11D)
.addReg(SystemZ::R15D);
// Add CFI for the new frame location.
unsigned HardFP = MRI->getDwarfRegNum(SystemZ::R11D, true);
unsigned CFIIndex = MMI.addFrameInst(
MCCFIInstruction::createDefCfaRegister(nullptr, HardFP));
BuildMI(MBB, MBBI, DL, ZII->get(TargetOpcode::CFI_INSTRUCTION))
.addCFIIndex(CFIIndex);
// Mark the FramePtr as live at the beginning of every block except
// the entry block. (We'll have marked R11 as live on entry when
// saving the GPRs.)
for (auto I = std::next(MF.begin()), E = MF.end(); I != E; ++I)
I->addLiveIn(SystemZ::R11D);
}
// Skip over the FPR saves.
SmallVector<unsigned, 8> CFIIndexes;
for (auto &Save : CSI) {
unsigned Reg = Save.getReg();
if (SystemZ::FP64BitRegClass.contains(Reg)) {
if (MBBI != MBB.end() &&
(MBBI->getOpcode() == SystemZ::STD ||
MBBI->getOpcode() == SystemZ::STDY))
++MBBI;
else
llvm_unreachable("Couldn't skip over FPR save");
// Add CFI for the this save.
unsigned DwarfReg = MRI->getDwarfRegNum(Reg, true);
int64_t Offset = getFrameIndexOffset(MF, Save.getFrameIdx());
unsigned CFIIndex = MMI.addFrameInst(MCCFIInstruction::createOffset(
nullptr, DwarfReg, SPOffsetFromCFA + Offset));
CFIIndexes.push_back(CFIIndex);
}
}
// Complete the CFI for the FPR saves, modelling them as taking effect
// after the last save.
for (auto CFIIndex : CFIIndexes) {
BuildMI(MBB, MBBI, DL, ZII->get(TargetOpcode::CFI_INSTRUCTION))
.addCFIIndex(CFIIndex);
}
}
void SystemZFrameLowering::emitPrologue(MachineFunction &MF) const {
MachineBasicBlock &MBB = MF.front();
MachineFrameInfo *MFFrame = MF.getFrameInfo();
const SystemZInstrInfo *ZII =
static_cast<const SystemZInstrInfo*>(MF.getTarget().getInstrInfo());
SystemZMachineFunctionInfo *ZFI = MF.getInfo<SystemZMachineFunctionInfo>();
MachineBasicBlock::iterator MBBI = MBB.begin();
MachineModuleInfo &MMI = MF.getMMI();
const std::vector<CalleeSavedInfo> &CSI = MFFrame->getCalleeSavedInfo();
bool HasFP = hasFP(MF);
DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
// The current offset of the stack pointer from the CFA.
int64_t SPOffsetFromCFA = -SystemZMC::CFAOffsetFromInitialSP;
if (ZFI->getLowSavedGPR()) {
// Skip over the GPR saves.
if (MBBI != MBB.end() && MBBI->getOpcode() == SystemZ::STMG)
++MBBI;
else
llvm_unreachable("Couldn't skip over GPR saves");
// Add CFI for the GPR saves.
MCSymbol *GPRSaveLabel = MMI.getContext().CreateTempSymbol();
BuildMI(MBB, MBBI, DL,
ZII->get(TargetOpcode::PROLOG_LABEL)).addSym(GPRSaveLabel);
for (std::vector<CalleeSavedInfo>::const_iterator
I = CSI.begin(), E = CSI.end(); I != E; ++I) {
unsigned Reg = I->getReg();
if (SystemZ::GR64BitRegClass.contains(Reg)) {
int64_t Offset = SPOffsetFromCFA + RegSpillOffsets[Reg];
MachineLocation StackSlot(MachineLocation::VirtualFP, Offset);
MachineLocation RegValue(Reg);
MMI.addFrameMove(GPRSaveLabel, StackSlot, RegValue);
}
}
}
uint64_t StackSize = getAllocatedStackSize(MF);
if (StackSize) {
// Allocate StackSize bytes.
int64_t Delta = -int64_t(StackSize);
emitIncrement(MBB, MBBI, DL, SystemZ::R15D, Delta, ZII);
// Add CFI for the allocation.
MCSymbol *AdjustSPLabel = MMI.getContext().CreateTempSymbol();
BuildMI(MBB, MBBI, DL, ZII->get(TargetOpcode::PROLOG_LABEL))
.addSym(AdjustSPLabel);
MachineLocation FPDest(MachineLocation::VirtualFP);
MachineLocation FPSrc(MachineLocation::VirtualFP, SPOffsetFromCFA + Delta);
MMI.addFrameMove(AdjustSPLabel, FPDest, FPSrc);
SPOffsetFromCFA += Delta;
}
if (HasFP) {
// Copy the base of the frame to R11.
BuildMI(MBB, MBBI, DL, ZII->get(SystemZ::LGR), SystemZ::R11D)
.addReg(SystemZ::R15D);
// Add CFI for the new frame location.
MCSymbol *SetFPLabel = MMI.getContext().CreateTempSymbol();
BuildMI(MBB, MBBI, DL, ZII->get(TargetOpcode::PROLOG_LABEL))
.addSym(SetFPLabel);
MachineLocation HardFP(SystemZ::R11D);
MachineLocation VirtualFP(MachineLocation::VirtualFP);
MMI.addFrameMove(SetFPLabel, HardFP, VirtualFP);
// Mark the FramePtr as live at the beginning of every block except
// the entry block. (We'll have marked R11 as live on entry when
// saving the GPRs.)
for (MachineFunction::iterator
I = llvm::next(MF.begin()), E = MF.end(); I != E; ++I)
I->addLiveIn(SystemZ::R11D);
}
// Skip over the FPR saves.
MCSymbol *FPRSaveLabel = 0;
for (std::vector<CalleeSavedInfo>::const_iterator
I = CSI.begin(), E = CSI.end(); I != E; ++I) {
unsigned Reg = I->getReg();
if (SystemZ::FP64BitRegClass.contains(Reg)) {
if (MBBI != MBB.end() &&
(MBBI->getOpcode() == SystemZ::STD ||
MBBI->getOpcode() == SystemZ::STDY))
++MBBI;
else
llvm_unreachable("Couldn't skip over FPR save");
// Add CFI for the this save.
if (!FPRSaveLabel)
FPRSaveLabel = MMI.getContext().CreateTempSymbol();
unsigned Reg = I->getReg();
int64_t Offset = getFrameIndexOffset(MF, I->getFrameIdx());
MachineLocation Slot(MachineLocation::VirtualFP,
SPOffsetFromCFA + Offset);
MachineLocation RegValue(Reg);
MMI.addFrameMove(FPRSaveLabel, Slot, RegValue);
}
}
// Complete the CFI for the FPR saves, modelling them as taking effect
// after the last save.
if (FPRSaveLabel)
BuildMI(MBB, MBBI, DL, ZII->get(TargetOpcode::PROLOG_LABEL))
.addSym(FPRSaveLabel);
}