| //===-- ThumbRegisterInfo.cpp - Thumb-1 Register Information -------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file contains the Thumb-1 implementation of the TargetRegisterInfo |
| // class. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "ThumbRegisterInfo.h" |
| #include "ARMBaseInstrInfo.h" |
| #include "ARMMachineFunctionInfo.h" |
| #include "ARMSubtarget.h" |
| #include "MCTargetDesc/ARMAddressingModes.h" |
| #include "llvm/CodeGen/MachineConstantPool.h" |
| #include "llvm/CodeGen/MachineFrameInfo.h" |
| #include "llvm/CodeGen/MachineFunction.h" |
| #include "llvm/CodeGen/MachineInstrBuilder.h" |
| #include "llvm/CodeGen/MachineRegisterInfo.h" |
| #include "llvm/CodeGen/RegisterScavenging.h" |
| #include "llvm/IR/Constants.h" |
| #include "llvm/IR/DerivedTypes.h" |
| #include "llvm/IR/Function.h" |
| #include "llvm/IR/LLVMContext.h" |
| #include "llvm/Support/CommandLine.h" |
| #include "llvm/Support/ErrorHandling.h" |
| #include "llvm/CodeGen/TargetFrameLowering.h" |
| #include "llvm/Target/TargetMachine.h" |
| |
| namespace llvm { |
| extern cl::opt<bool> ReuseFrameIndexVals; |
| } |
| |
| using namespace llvm; |
| |
| ThumbRegisterInfo::ThumbRegisterInfo() : ARMBaseRegisterInfo() {} |
| |
| const TargetRegisterClass * |
| ThumbRegisterInfo::getLargestLegalSuperClass(const TargetRegisterClass *RC, |
| const MachineFunction &MF) const { |
| if (!MF.getSubtarget<ARMSubtarget>().isThumb1Only()) |
| return ARMBaseRegisterInfo::getLargestLegalSuperClass(RC, MF); |
| |
| if (ARM::tGPRRegClass.hasSubClassEq(RC)) |
| return &ARM::tGPRRegClass; |
| return ARMBaseRegisterInfo::getLargestLegalSuperClass(RC, MF); |
| } |
| |
| const TargetRegisterClass * |
| ThumbRegisterInfo::getPointerRegClass(const MachineFunction &MF, |
| unsigned Kind) const { |
| if (!MF.getSubtarget<ARMSubtarget>().isThumb1Only()) |
| return ARMBaseRegisterInfo::getPointerRegClass(MF, Kind); |
| return &ARM::tGPRRegClass; |
| } |
| |
| static void emitThumb1LoadConstPool(MachineBasicBlock &MBB, |
| MachineBasicBlock::iterator &MBBI, |
| const DebugLoc &dl, unsigned DestReg, |
| unsigned SubIdx, int Val, |
| ARMCC::CondCodes Pred, unsigned PredReg, |
| unsigned MIFlags) { |
| MachineFunction &MF = *MBB.getParent(); |
| const ARMSubtarget &STI = MF.getSubtarget<ARMSubtarget>(); |
| const TargetInstrInfo &TII = *STI.getInstrInfo(); |
| MachineConstantPool *ConstantPool = MF.getConstantPool(); |
| const Constant *C = ConstantInt::get( |
| Type::getInt32Ty(MBB.getParent()->getFunction().getContext()), Val); |
| unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4); |
| |
| BuildMI(MBB, MBBI, dl, TII.get(ARM::tLDRpci)) |
| .addReg(DestReg, getDefRegState(true), SubIdx) |
| .addConstantPoolIndex(Idx).addImm(Pred).addReg(PredReg) |
| .setMIFlags(MIFlags); |
| } |
| |
| static void emitThumb2LoadConstPool(MachineBasicBlock &MBB, |
| MachineBasicBlock::iterator &MBBI, |
| const DebugLoc &dl, unsigned DestReg, |
| unsigned SubIdx, int Val, |
| ARMCC::CondCodes Pred, unsigned PredReg, |
| unsigned MIFlags) { |
| MachineFunction &MF = *MBB.getParent(); |
| const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo(); |
| MachineConstantPool *ConstantPool = MF.getConstantPool(); |
| const Constant *C = ConstantInt::get( |
| Type::getInt32Ty(MBB.getParent()->getFunction().getContext()), Val); |
| unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4); |
| |
| BuildMI(MBB, MBBI, dl, TII.get(ARM::t2LDRpci)) |
| .addReg(DestReg, getDefRegState(true), SubIdx) |
| .addConstantPoolIndex(Idx) |
| .add(predOps(ARMCC::AL)) |
| .setMIFlags(MIFlags); |
| } |
| |
| /// emitLoadConstPool - Emits a load from constpool to materialize the |
| /// specified immediate. |
| void ThumbRegisterInfo::emitLoadConstPool( |
| MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI, |
| const DebugLoc &dl, unsigned DestReg, unsigned SubIdx, int Val, |
| ARMCC::CondCodes Pred, unsigned PredReg, unsigned MIFlags) const { |
| MachineFunction &MF = *MBB.getParent(); |
| const ARMSubtarget &STI = MF.getSubtarget<ARMSubtarget>(); |
| if (STI.isThumb1Only()) { |
| assert((isARMLowRegister(DestReg) || isVirtualRegister(DestReg)) && |
| "Thumb1 does not have ldr to high register"); |
| return emitThumb1LoadConstPool(MBB, MBBI, dl, DestReg, SubIdx, Val, Pred, |
| PredReg, MIFlags); |
| } |
| return emitThumb2LoadConstPool(MBB, MBBI, dl, DestReg, SubIdx, Val, Pred, |
| PredReg, MIFlags); |
| } |
| |
| /// emitThumbRegPlusImmInReg - Emits a series of instructions to materialize |
| /// a destreg = basereg + immediate in Thumb code. Materialize the immediate |
| /// in a register using mov / mvn sequences or load the immediate from a |
| /// constpool entry. |
| static void emitThumbRegPlusImmInReg( |
| MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI, |
| const DebugLoc &dl, unsigned DestReg, unsigned BaseReg, int NumBytes, |
| bool CanChangeCC, const TargetInstrInfo &TII, |
| const ARMBaseRegisterInfo &MRI, unsigned MIFlags = MachineInstr::NoFlags) { |
| MachineFunction &MF = *MBB.getParent(); |
| const ARMSubtarget &ST = MF.getSubtarget<ARMSubtarget>(); |
| bool isHigh = !isARMLowRegister(DestReg) || |
| (BaseReg != 0 && !isARMLowRegister(BaseReg)); |
| bool isSub = false; |
| // Subtract doesn't have high register version. Load the negative value |
| // if either base or dest register is a high register. Also, if do not |
| // issue sub as part of the sequence if condition register is to be |
| // preserved. |
| if (NumBytes < 0 && !isHigh && CanChangeCC) { |
| isSub = true; |
| NumBytes = -NumBytes; |
| } |
| unsigned LdReg = DestReg; |
| if (DestReg == ARM::SP) |
| assert(BaseReg == ARM::SP && "Unexpected!"); |
| if (!isARMLowRegister(DestReg) && !MRI.isVirtualRegister(DestReg)) |
| LdReg = MF.getRegInfo().createVirtualRegister(&ARM::tGPRRegClass); |
| |
| if (NumBytes <= 255 && NumBytes >= 0 && CanChangeCC) { |
| BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8), LdReg) |
| .add(t1CondCodeOp()) |
| .addImm(NumBytes) |
| .setMIFlags(MIFlags); |
| } else if (NumBytes < 0 && NumBytes >= -255 && CanChangeCC) { |
| BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8), LdReg) |
| .add(t1CondCodeOp()) |
| .addImm(NumBytes) |
| .setMIFlags(MIFlags); |
| BuildMI(MBB, MBBI, dl, TII.get(ARM::tRSB), LdReg) |
| .add(t1CondCodeOp()) |
| .addReg(LdReg, RegState::Kill) |
| .setMIFlags(MIFlags); |
| } else if (ST.genExecuteOnly()) { |
| BuildMI(MBB, MBBI, dl, TII.get(ARM::t2MOVi32imm), LdReg) |
| .addImm(NumBytes).setMIFlags(MIFlags); |
| } else |
| MRI.emitLoadConstPool(MBB, MBBI, dl, LdReg, 0, NumBytes, ARMCC::AL, 0, |
| MIFlags); |
| |
| // Emit add / sub. |
| int Opc = (isSub) ? ARM::tSUBrr |
| : ((isHigh || !CanChangeCC) ? ARM::tADDhirr : ARM::tADDrr); |
| MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg); |
| if (Opc != ARM::tADDhirr) |
| MIB = MIB.add(t1CondCodeOp()); |
| if (DestReg == ARM::SP || isSub) |
| MIB.addReg(BaseReg).addReg(LdReg, RegState::Kill); |
| else |
| MIB.addReg(LdReg).addReg(BaseReg, RegState::Kill); |
| MIB.add(predOps(ARMCC::AL)); |
| } |
| |
| /// emitThumbRegPlusImmediate - Emits a series of instructions to materialize |
| /// a destreg = basereg + immediate in Thumb code. Tries a series of ADDs or |
| /// SUBs first, and uses a constant pool value if the instruction sequence would |
| /// be too long. This is allowed to modify the condition flags. |
| void llvm::emitThumbRegPlusImmediate(MachineBasicBlock &MBB, |
| MachineBasicBlock::iterator &MBBI, |
| const DebugLoc &dl, unsigned DestReg, |
| unsigned BaseReg, int NumBytes, |
| const TargetInstrInfo &TII, |
| const ARMBaseRegisterInfo &MRI, |
| unsigned MIFlags) { |
| bool isSub = NumBytes < 0; |
| unsigned Bytes = (unsigned)NumBytes; |
| if (isSub) Bytes = -NumBytes; |
| |
| int CopyOpc = 0; |
| unsigned CopyBits = 0; |
| unsigned CopyScale = 1; |
| bool CopyNeedsCC = false; |
| int ExtraOpc = 0; |
| unsigned ExtraBits = 0; |
| unsigned ExtraScale = 1; |
| bool ExtraNeedsCC = false; |
| |
| // Strategy: |
| // We need to select two types of instruction, maximizing the available |
| // immediate range of each. The instructions we use will depend on whether |
| // DestReg and BaseReg are low, high or the stack pointer. |
| // * CopyOpc - DestReg = BaseReg + imm |
| // This will be emitted once if DestReg != BaseReg, and never if |
| // DestReg == BaseReg. |
| // * ExtraOpc - DestReg = DestReg + imm |
| // This will be emitted as many times as necessary to add the |
| // full immediate. |
| // If the immediate ranges of these instructions are not large enough to cover |
| // NumBytes with a reasonable number of instructions, we fall back to using a |
| // value loaded from a constant pool. |
| if (DestReg == ARM::SP) { |
| if (BaseReg == ARM::SP) { |
| // sp -> sp |
| // Already in right reg, no copy needed |
| } else { |
| // low -> sp or high -> sp |
| CopyOpc = ARM::tMOVr; |
| CopyBits = 0; |
| } |
| ExtraOpc = isSub ? ARM::tSUBspi : ARM::tADDspi; |
| ExtraBits = 7; |
| ExtraScale = 4; |
| } else if (isARMLowRegister(DestReg)) { |
| if (BaseReg == ARM::SP) { |
| // sp -> low |
| assert(!isSub && "Thumb1 does not have tSUBrSPi"); |
| CopyOpc = ARM::tADDrSPi; |
| CopyBits = 8; |
| CopyScale = 4; |
| } else if (DestReg == BaseReg) { |
| // low -> same low |
| // Already in right reg, no copy needed |
| } else if (isARMLowRegister(BaseReg)) { |
| // low -> different low |
| CopyOpc = isSub ? ARM::tSUBi3 : ARM::tADDi3; |
| CopyBits = 3; |
| CopyNeedsCC = true; |
| } else { |
| // high -> low |
| CopyOpc = ARM::tMOVr; |
| CopyBits = 0; |
| } |
| ExtraOpc = isSub ? ARM::tSUBi8 : ARM::tADDi8; |
| ExtraBits = 8; |
| ExtraNeedsCC = true; |
| } else /* DestReg is high */ { |
| if (DestReg == BaseReg) { |
| // high -> same high |
| // Already in right reg, no copy needed |
| } else { |
| // {low,high,sp} -> high |
| CopyOpc = ARM::tMOVr; |
| CopyBits = 0; |
| } |
| ExtraOpc = 0; |
| } |
| |
| // We could handle an unaligned immediate with an unaligned copy instruction |
| // and an aligned extra instruction, but this case is not currently needed. |
| assert(((Bytes & 3) == 0 || ExtraScale == 1) && |
| "Unaligned offset, but all instructions require alignment"); |
| |
| unsigned CopyRange = ((1 << CopyBits) - 1) * CopyScale; |
| // If we would emit the copy with an immediate of 0, just use tMOVr. |
| if (CopyOpc && Bytes < CopyScale) { |
| CopyOpc = ARM::tMOVr; |
| CopyScale = 1; |
| CopyNeedsCC = false; |
| CopyRange = 0; |
| } |
| unsigned ExtraRange = ((1 << ExtraBits) - 1) * ExtraScale; // per instruction |
| unsigned RequiredCopyInstrs = CopyOpc ? 1 : 0; |
| unsigned RangeAfterCopy = (CopyRange > Bytes) ? 0 : (Bytes - CopyRange); |
| |
| // We could handle this case when the copy instruction does not require an |
| // aligned immediate, but we do not currently do this. |
| assert(RangeAfterCopy % ExtraScale == 0 && |
| "Extra instruction requires immediate to be aligned"); |
| |
| unsigned RequiredExtraInstrs; |
| if (ExtraRange) |
| RequiredExtraInstrs = alignTo(RangeAfterCopy, ExtraRange) / ExtraRange; |
| else if (RangeAfterCopy > 0) |
| // We need an extra instruction but none is available |
| RequiredExtraInstrs = 1000000; |
| else |
| RequiredExtraInstrs = 0; |
| unsigned RequiredInstrs = RequiredCopyInstrs + RequiredExtraInstrs; |
| unsigned Threshold = (DestReg == ARM::SP) ? 3 : 2; |
| |
| // Use a constant pool, if the sequence of ADDs/SUBs is too expensive. |
| if (RequiredInstrs > Threshold) { |
| emitThumbRegPlusImmInReg(MBB, MBBI, dl, |
| DestReg, BaseReg, NumBytes, true, |
| TII, MRI, MIFlags); |
| return; |
| } |
| |
| // Emit zero or one copy instructions |
| if (CopyOpc) { |
| unsigned CopyImm = std::min(Bytes, CopyRange) / CopyScale; |
| Bytes -= CopyImm * CopyScale; |
| |
| MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(CopyOpc), DestReg); |
| if (CopyNeedsCC) |
| MIB = MIB.add(t1CondCodeOp()); |
| MIB.addReg(BaseReg, RegState::Kill); |
| if (CopyOpc != ARM::tMOVr) { |
| MIB.addImm(CopyImm); |
| } |
| MIB.setMIFlags(MIFlags).add(predOps(ARMCC::AL)); |
| |
| BaseReg = DestReg; |
| } |
| |
| // Emit zero or more in-place add/sub instructions |
| while (Bytes) { |
| unsigned ExtraImm = std::min(Bytes, ExtraRange) / ExtraScale; |
| Bytes -= ExtraImm * ExtraScale; |
| |
| MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(ExtraOpc), DestReg); |
| if (ExtraNeedsCC) |
| MIB = MIB.add(t1CondCodeOp()); |
| MIB.addReg(BaseReg) |
| .addImm(ExtraImm) |
| .add(predOps(ARMCC::AL)) |
| .setMIFlags(MIFlags); |
| } |
| } |
| |
| static void removeOperands(MachineInstr &MI, unsigned i) { |
| unsigned Op = i; |
| for (unsigned e = MI.getNumOperands(); i != e; ++i) |
| MI.RemoveOperand(Op); |
| } |
| |
| /// convertToNonSPOpcode - Change the opcode to the non-SP version, because |
| /// we're replacing the frame index with a non-SP register. |
| static unsigned convertToNonSPOpcode(unsigned Opcode) { |
| switch (Opcode) { |
| case ARM::tLDRspi: |
| return ARM::tLDRi; |
| |
| case ARM::tSTRspi: |
| return ARM::tSTRi; |
| } |
| |
| return Opcode; |
| } |
| |
| bool ThumbRegisterInfo::rewriteFrameIndex(MachineBasicBlock::iterator II, |
| unsigned FrameRegIdx, |
| unsigned FrameReg, int &Offset, |
| const ARMBaseInstrInfo &TII) const { |
| MachineInstr &MI = *II; |
| MachineBasicBlock &MBB = *MI.getParent(); |
| assert(MBB.getParent()->getSubtarget<ARMSubtarget>().isThumb1Only() && |
| "This isn't needed for thumb2!"); |
| DebugLoc dl = MI.getDebugLoc(); |
| MachineInstrBuilder MIB(*MBB.getParent(), &MI); |
| unsigned Opcode = MI.getOpcode(); |
| const MCInstrDesc &Desc = MI.getDesc(); |
| unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask); |
| |
| if (Opcode == ARM::tADDframe) { |
| Offset += MI.getOperand(FrameRegIdx+1).getImm(); |
| unsigned DestReg = MI.getOperand(0).getReg(); |
| |
| emitThumbRegPlusImmediate(MBB, II, dl, DestReg, FrameReg, Offset, TII, |
| *this); |
| MBB.erase(II); |
| return true; |
| } else { |
| if (AddrMode != ARMII::AddrModeT1_s) |
| llvm_unreachable("Unsupported addressing mode!"); |
| |
| unsigned ImmIdx = FrameRegIdx + 1; |
| int InstrOffs = MI.getOperand(ImmIdx).getImm(); |
| unsigned NumBits = (FrameReg == ARM::SP) ? 8 : 5; |
| unsigned Scale = 4; |
| |
| Offset += InstrOffs * Scale; |
| assert((Offset & (Scale - 1)) == 0 && "Can't encode this offset!"); |
| |
| // Common case: small offset, fits into instruction. |
| MachineOperand &ImmOp = MI.getOperand(ImmIdx); |
| int ImmedOffset = Offset / Scale; |
| unsigned Mask = (1 << NumBits) - 1; |
| |
| if ((unsigned)Offset <= Mask * Scale) { |
| // Replace the FrameIndex with the frame register (e.g., sp). |
| MI.getOperand(FrameRegIdx).ChangeToRegister(FrameReg, false); |
| ImmOp.ChangeToImmediate(ImmedOffset); |
| |
| // If we're using a register where sp was stored, convert the instruction |
| // to the non-SP version. |
| unsigned NewOpc = convertToNonSPOpcode(Opcode); |
| if (NewOpc != Opcode && FrameReg != ARM::SP) |
| MI.setDesc(TII.get(NewOpc)); |
| |
| return true; |
| } |
| |
| NumBits = 5; |
| Mask = (1 << NumBits) - 1; |
| |
| // If this is a thumb spill / restore, we will be using a constpool load to |
| // materialize the offset. |
| if (Opcode == ARM::tLDRspi || Opcode == ARM::tSTRspi) { |
| ImmOp.ChangeToImmediate(0); |
| } else { |
| // Otherwise, it didn't fit. Pull in what we can to simplify the immed. |
| ImmedOffset = ImmedOffset & Mask; |
| ImmOp.ChangeToImmediate(ImmedOffset); |
| Offset &= ~(Mask * Scale); |
| } |
| } |
| |
| return Offset == 0; |
| } |
| |
| void ThumbRegisterInfo::resolveFrameIndex(MachineInstr &MI, unsigned BaseReg, |
| int64_t Offset) const { |
| const MachineFunction &MF = *MI.getParent()->getParent(); |
| const ARMSubtarget &STI = MF.getSubtarget<ARMSubtarget>(); |
| if (!STI.isThumb1Only()) |
| return ARMBaseRegisterInfo::resolveFrameIndex(MI, BaseReg, Offset); |
| |
| const ARMBaseInstrInfo &TII = *STI.getInstrInfo(); |
| int Off = Offset; // ARM doesn't need the general 64-bit offsets |
| unsigned i = 0; |
| |
| while (!MI.getOperand(i).isFI()) { |
| ++i; |
| assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!"); |
| } |
| bool Done = rewriteFrameIndex(MI, i, BaseReg, Off, TII); |
| assert (Done && "Unable to resolve frame index!"); |
| (void)Done; |
| } |
| |
| /// saveScavengerRegister - Spill the register so it can be used by the |
| /// register scavenger. Return true. |
| bool ThumbRegisterInfo::saveScavengerRegister( |
| MachineBasicBlock &MBB, MachineBasicBlock::iterator I, |
| MachineBasicBlock::iterator &UseMI, const TargetRegisterClass *RC, |
| unsigned Reg) const { |
| |
| const ARMSubtarget &STI = MBB.getParent()->getSubtarget<ARMSubtarget>(); |
| if (!STI.isThumb1Only()) |
| return ARMBaseRegisterInfo::saveScavengerRegister(MBB, I, UseMI, RC, Reg); |
| |
| // Thumb1 can't use the emergency spill slot on the stack because |
| // ldr/str immediate offsets must be positive, and if we're referencing |
| // off the frame pointer (if, for example, there are alloca() calls in |
| // the function, the offset will be negative. Use R12 instead since that's |
| // a call clobbered register that we know won't be used in Thumb1 mode. |
| const TargetInstrInfo &TII = *STI.getInstrInfo(); |
| DebugLoc DL; |
| BuildMI(MBB, I, DL, TII.get(ARM::tMOVr)) |
| .addReg(ARM::R12, RegState::Define) |
| .addReg(Reg, RegState::Kill) |
| .add(predOps(ARMCC::AL)); |
| |
| // The UseMI is where we would like to restore the register. If there's |
| // interference with R12 before then, however, we'll need to restore it |
| // before that instead and adjust the UseMI. |
| bool done = false; |
| for (MachineBasicBlock::iterator II = I; !done && II != UseMI ; ++II) { |
| if (II->isDebugInstr()) |
| continue; |
| // If this instruction affects R12, adjust our restore point. |
| for (unsigned i = 0, e = II->getNumOperands(); i != e; ++i) { |
| const MachineOperand &MO = II->getOperand(i); |
| if (MO.isRegMask() && MO.clobbersPhysReg(ARM::R12)) { |
| UseMI = II; |
| done = true; |
| break; |
| } |
| if (!MO.isReg() || MO.isUndef() || !MO.getReg() || |
| TargetRegisterInfo::isVirtualRegister(MO.getReg())) |
| continue; |
| if (MO.getReg() == ARM::R12) { |
| UseMI = II; |
| done = true; |
| break; |
| } |
| } |
| } |
| // Restore the register from R12 |
| BuildMI(MBB, UseMI, DL, TII.get(ARM::tMOVr)) |
| .addReg(Reg, RegState::Define) |
| .addReg(ARM::R12, RegState::Kill) |
| .add(predOps(ARMCC::AL)); |
| |
| return true; |
| } |
| |
| void ThumbRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II, |
| int SPAdj, unsigned FIOperandNum, |
| RegScavenger *RS) const { |
| MachineInstr &MI = *II; |
| MachineBasicBlock &MBB = *MI.getParent(); |
| MachineFunction &MF = *MBB.getParent(); |
| const ARMSubtarget &STI = MF.getSubtarget<ARMSubtarget>(); |
| if (!STI.isThumb1Only()) |
| return ARMBaseRegisterInfo::eliminateFrameIndex(II, SPAdj, FIOperandNum, |
| RS); |
| |
| unsigned VReg = 0; |
| const ARMBaseInstrInfo &TII = *STI.getInstrInfo(); |
| DebugLoc dl = MI.getDebugLoc(); |
| MachineInstrBuilder MIB(*MBB.getParent(), &MI); |
| |
| unsigned FrameReg; |
| int FrameIndex = MI.getOperand(FIOperandNum).getIndex(); |
| const ARMFrameLowering *TFI = getFrameLowering(MF); |
| int Offset = TFI->ResolveFrameIndexReference(MF, FrameIndex, FrameReg, SPAdj); |
| |
| // PEI::scavengeFrameVirtualRegs() cannot accurately track SPAdj because the |
| // call frame setup/destroy instructions have already been eliminated. That |
| // means the stack pointer cannot be used to access the emergency spill slot |
| // when !hasReservedCallFrame(). |
| #ifndef NDEBUG |
| if (RS && FrameReg == ARM::SP && RS->isScavengingFrameIndex(FrameIndex)){ |
| assert(STI.getFrameLowering()->hasReservedCallFrame(MF) && |
| "Cannot use SP to access the emergency spill slot in " |
| "functions without a reserved call frame"); |
| assert(!MF.getFrameInfo().hasVarSizedObjects() && |
| "Cannot use SP to access the emergency spill slot in " |
| "functions with variable sized frame objects"); |
| } |
| #endif // NDEBUG |
| |
| // Special handling of dbg_value instructions. |
| if (MI.isDebugValue()) { |
| MI.getOperand(FIOperandNum). ChangeToRegister(FrameReg, false /*isDef*/); |
| MI.getOperand(FIOperandNum+1).ChangeToImmediate(Offset); |
| return; |
| } |
| |
| // Modify MI as necessary to handle as much of 'Offset' as possible |
| assert(MF.getInfo<ARMFunctionInfo>()->isThumbFunction() && |
| "This eliminateFrameIndex only supports Thumb1!"); |
| if (rewriteFrameIndex(MI, FIOperandNum, FrameReg, Offset, TII)) |
| return; |
| |
| // If we get here, the immediate doesn't fit into the instruction. We folded |
| // as much as possible above, handle the rest, providing a register that is |
| // SP+LargeImm. |
| assert(Offset && "This code isn't needed if offset already handled!"); |
| |
| unsigned Opcode = MI.getOpcode(); |
| |
| // Remove predicate first. |
| int PIdx = MI.findFirstPredOperandIdx(); |
| if (PIdx != -1) |
| removeOperands(MI, PIdx); |
| |
| if (MI.mayLoad()) { |
| // Use the destination register to materialize sp + offset. |
| unsigned TmpReg = MI.getOperand(0).getReg(); |
| bool UseRR = false; |
| if (Opcode == ARM::tLDRspi) { |
| if (FrameReg == ARM::SP || STI.genExecuteOnly()) |
| emitThumbRegPlusImmInReg(MBB, II, dl, TmpReg, FrameReg, |
| Offset, false, TII, *this); |
| else { |
| emitLoadConstPool(MBB, II, dl, TmpReg, 0, Offset); |
| UseRR = true; |
| } |
| } else { |
| emitThumbRegPlusImmediate(MBB, II, dl, TmpReg, FrameReg, Offset, TII, |
| *this); |
| } |
| |
| MI.setDesc(TII.get(UseRR ? ARM::tLDRr : ARM::tLDRi)); |
| MI.getOperand(FIOperandNum).ChangeToRegister(TmpReg, false, false, true); |
| if (UseRR) |
| // Use [reg, reg] addrmode. Replace the immediate operand w/ the frame |
| // register. The offset is already handled in the vreg value. |
| MI.getOperand(FIOperandNum+1).ChangeToRegister(FrameReg, false, false, |
| false); |
| } else if (MI.mayStore()) { |
| VReg = MF.getRegInfo().createVirtualRegister(&ARM::tGPRRegClass); |
| bool UseRR = false; |
| |
| if (Opcode == ARM::tSTRspi) { |
| if (FrameReg == ARM::SP || STI.genExecuteOnly()) |
| emitThumbRegPlusImmInReg(MBB, II, dl, VReg, FrameReg, |
| Offset, false, TII, *this); |
| else { |
| emitLoadConstPool(MBB, II, dl, VReg, 0, Offset); |
| UseRR = true; |
| } |
| } else |
| emitThumbRegPlusImmediate(MBB, II, dl, VReg, FrameReg, Offset, TII, |
| *this); |
| MI.setDesc(TII.get(UseRR ? ARM::tSTRr : ARM::tSTRi)); |
| MI.getOperand(FIOperandNum).ChangeToRegister(VReg, false, false, true); |
| if (UseRR) |
| // Use [reg, reg] addrmode. Replace the immediate operand w/ the frame |
| // register. The offset is already handled in the vreg value. |
| MI.getOperand(FIOperandNum+1).ChangeToRegister(FrameReg, false, false, |
| false); |
| } else { |
| llvm_unreachable("Unexpected opcode!"); |
| } |
| |
| // Add predicate back if it's needed. |
| if (MI.isPredicable()) |
| MIB.add(predOps(ARMCC::AL)); |
| } |
