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//===- Thumb1RegisterInfo.cpp - Thumb-1 Register Information ----*- C++ -*-===//
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// The LLVM Compiler Infrastructure
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//===----------------------------------------------------------------------===//
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// This file contains the Thumb-1 implementation of the TargetRegisterInfo
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//===----------------------------------------------------------------------===//
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#include "ARMAddressingModes.h"
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#include "ARMBaseInstrInfo.h"
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#include "ARMMachineFunctionInfo.h"
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#include "ARMSubtarget.h"
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#include "Thumb1InstrInfo.h"
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#include "Thumb1RegisterInfo.h"
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#include "llvm/Constants.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/Function.h"
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#include "llvm/LLVMContext.h"
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#include "llvm/CodeGen/MachineConstantPool.h"
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#include "llvm/CodeGen/MachineFrameInfo.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineInstrBuilder.h"
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#include "llvm/CodeGen/MachineLocation.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#include "llvm/Target/TargetFrameInfo.h"
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/ADT/BitVector.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/raw_ostream.h"
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Thumb1RegisterInfo::Thumb1RegisterInfo(const ARMBaseInstrInfo &tii,
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const ARMSubtarget &sti)
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: ARMBaseRegisterInfo(tii, sti) {
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/// emitLoadConstPool - Emits a load from constpool to materialize the
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/// specified immediate.
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void Thumb1RegisterInfo::emitLoadConstPool(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator &MBBI,
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unsigned DestReg, unsigned SubIdx,
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ARMCC::CondCodes Pred,
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unsigned PredReg) const {
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MachineFunction &MF = *MBB.getParent();
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MachineConstantPool *ConstantPool = MF.getConstantPool();
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Constant *C = ConstantInt::get(
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Type::getInt32Ty(MBB.getParent()->getFunction()->getContext()), Val);
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unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4);
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BuildMI(MBB, MBBI, dl, TII.get(ARM::tLDRcp))
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.addReg(DestReg, getDefRegState(true), SubIdx)
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.addConstantPoolIndex(Idx).addImm(Pred).addReg(PredReg);
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const TargetRegisterClass*
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Thumb1RegisterInfo::getPhysicalRegisterRegClass(unsigned Reg, EVT VT) const {
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if (isARMLowRegister(Reg))
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return ARM::tGPRRegisterClass;
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case ARM::R8: case ARM::R9: case ARM::R10: case ARM::R11:
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case ARM::R12: case ARM::SP: case ARM::LR: case ARM::PC:
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return ARM::GPRRegisterClass;
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return TargetRegisterInfo::getPhysicalRegisterRegClass(Reg, VT);
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bool Thumb1RegisterInfo::hasReservedCallFrame(MachineFunction &MF) const {
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const MachineFrameInfo *FFI = MF.getFrameInfo();
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unsigned CFSize = FFI->getMaxCallFrameSize();
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// It's not always a good idea to include the call frame as part of the
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// stack frame. ARM (especially Thumb) has small immediate offset to
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// address the stack frame. So a large call frame can cause poor codegen
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// and may even makes it impossible to scavenge a register.
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if (CFSize >= ((1 << 8) - 1) * 4 / 2) // Half of imm8 * 4
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return !MF.getFrameInfo()->hasVarSizedObjects();
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/// emitThumbRegPlusImmInReg - Emits a series of instructions to materialize
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/// a destreg = basereg + immediate in Thumb code. Materialize the immediate
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/// in a register using mov / mvn sequences or load the immediate from a
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void emitThumbRegPlusImmInReg(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator &MBBI,
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unsigned DestReg, unsigned BaseReg,
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int NumBytes, bool CanChangeCC,
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const TargetInstrInfo &TII,
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const Thumb1RegisterInfo& MRI,
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MachineFunction &MF = *MBB.getParent();
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bool isHigh = !isARMLowRegister(DestReg) ||
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(BaseReg != 0 && !isARMLowRegister(BaseReg));
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// Subtract doesn't have high register version. Load the negative value
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// if either base or dest register is a high register. Also, if do not
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// issue sub as part of the sequence if condition register is to be
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if (NumBytes < 0 && !isHigh && CanChangeCC) {
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NumBytes = -NumBytes;
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unsigned LdReg = DestReg;
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if (DestReg == ARM::SP) {
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assert(BaseReg == ARM::SP && "Unexpected!");
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LdReg = MF.getRegInfo().createVirtualRegister(ARM::tGPRRegisterClass);
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if (NumBytes <= 255 && NumBytes >= 0)
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AddDefaultT1CC(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8), LdReg))
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else if (NumBytes < 0 && NumBytes >= -255) {
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AddDefaultT1CC(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8), LdReg))
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AddDefaultT1CC(BuildMI(MBB, MBBI, dl, TII.get(ARM::tRSB), LdReg))
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.addReg(LdReg, RegState::Kill);
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MRI.emitLoadConstPool(MBB, MBBI, dl, LdReg, 0, NumBytes);
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int Opc = (isSub) ? ARM::tSUBrr : (isHigh ? ARM::tADDhirr : ARM::tADDrr);
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MachineInstrBuilder MIB =
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BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg);
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if (Opc != ARM::tADDhirr)
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MIB = AddDefaultT1CC(MIB);
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if (DestReg == ARM::SP || isSub)
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MIB.addReg(BaseReg).addReg(LdReg, RegState::Kill);
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MIB.addReg(LdReg).addReg(BaseReg, RegState::Kill);
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/// calcNumMI - Returns the number of instructions required to materialize
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/// the specific add / sub r, c instruction.
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static unsigned calcNumMI(int Opc, int ExtraOpc, unsigned Bytes,
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unsigned NumBits, unsigned Scale) {
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unsigned Chunk = ((1 << NumBits) - 1) * Scale;
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if (Opc == ARM::tADDrSPi) {
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unsigned ThisVal = (Bytes > Chunk) ? Chunk : Bytes;
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Scale = 1; // Followed by a number of tADDi8.
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Chunk = ((1 << NumBits) - 1) * Scale;
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NumMIs += Bytes / Chunk;
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if ((Bytes % Chunk) != 0)
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/// emitThumbRegPlusImmediate - Emits a series of instructions to materialize
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/// a destreg = basereg + immediate in Thumb code.
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void emitThumbRegPlusImmediate(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator &MBBI,
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unsigned DestReg, unsigned BaseReg,
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int NumBytes, const TargetInstrInfo &TII,
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const Thumb1RegisterInfo& MRI,
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bool isSub = NumBytes < 0;
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unsigned Bytes = (unsigned)NumBytes;
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if (isSub) Bytes = -NumBytes;
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bool isMul4 = (Bytes & 3) == 0;
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bool isTwoAddr = false;
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bool DstNotEqBase = false;
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unsigned NumBits = 1;
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bool NeedPred = false;
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if (DestReg == BaseReg && BaseReg == ARM::SP) {
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assert(isMul4 && "Thumb sp inc / dec size must be multiple of 4!");
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Opc = isSub ? ARM::tSUBspi : ARM::tADDspi;
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} else if (!isSub && BaseReg == ARM::SP) {
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// r1 = add sp, 100 * 4
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ExtraOpc = ARM::tADDi3;
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if (DestReg != BaseReg)
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if (DestReg == ARM::SP) {
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Opc = isSub ? ARM::tSUBspi : ARM::tADDspi;
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assert(isMul4 && "Thumb sp inc / dec size must be multiple of 4!");
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Opc = isSub ? ARM::tSUBi8 : ARM::tADDi8;
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NeedPred = NeedCC = true;
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unsigned NumMIs = calcNumMI(Opc, ExtraOpc, Bytes, NumBits, Scale);
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unsigned Threshold = (DestReg == ARM::SP) ? 3 : 2;
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if (NumMIs > Threshold) {
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// This will expand into too many instructions. Load the immediate from a
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emitThumbRegPlusImmInReg(MBB, MBBI, DestReg, BaseReg, NumBytes, true, TII,
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if (isARMLowRegister(DestReg) && isARMLowRegister(BaseReg)) {
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// If both are low registers, emit DestReg = add BaseReg, max(Imm, 7)
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unsigned Chunk = (1 << 3) - 1;
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unsigned ThisVal = (Bytes > Chunk) ? Chunk : Bytes;
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const TargetInstrDesc &TID = TII.get(isSub ? ARM::tSUBi3 : ARM::tADDi3);
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const MachineInstrBuilder MIB =
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AddDefaultT1CC(BuildMI(MBB, MBBI, dl, TID, DestReg));
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AddDefaultPred(MIB.addReg(BaseReg, RegState::Kill).addImm(ThisVal));
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BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr), DestReg)
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.addReg(BaseReg, RegState::Kill);
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unsigned Chunk = ((1 << NumBits) - 1) * Scale;
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unsigned ThisVal = (Bytes > Chunk) ? Chunk : Bytes;
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// Build the new tADD / tSUB.
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MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg);
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MIB = AddDefaultT1CC(MIB);
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MIB .addReg(DestReg).addImm(ThisVal);
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MIB = AddDefaultPred(MIB);
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bool isKill = BaseReg != ARM::SP;
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MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg);
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MIB = AddDefaultT1CC(MIB);
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MIB.addReg(BaseReg, getKillRegState(isKill)).addImm(ThisVal);
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MIB = AddDefaultPred(MIB);
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if (Opc == ARM::tADDrSPi) {
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Chunk = ((1 << NumBits) - 1) * Scale;
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Opc = isSub ? ARM::tSUBi8 : ARM::tADDi8;
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NeedPred = NeedCC = isTwoAddr = true;
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const TargetInstrDesc &TID = TII.get(ExtraOpc);
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AddDefaultPred(AddDefaultT1CC(BuildMI(MBB, MBBI, dl, TID, DestReg))
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.addReg(DestReg, RegState::Kill)
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.addImm(((unsigned)NumBytes) & 3));
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static void emitSPUpdate(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator &MBBI,
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const TargetInstrInfo &TII, DebugLoc dl,
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const Thumb1RegisterInfo &MRI,
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emitThumbRegPlusImmediate(MBB, MBBI, ARM::SP, ARM::SP, NumBytes, TII,
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void Thumb1RegisterInfo::
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eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
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MachineBasicBlock::iterator I) const {
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if (!hasReservedCallFrame(MF)) {
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// If we have alloca, convert as follows:
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// ADJCALLSTACKDOWN -> sub, sp, sp, amount
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// ADJCALLSTACKUP -> add, sp, sp, amount
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MachineInstr *Old = I;
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DebugLoc dl = Old->getDebugLoc();
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unsigned Amount = Old->getOperand(0).getImm();
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// We need to keep the stack aligned properly. To do this, we round the
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// amount of space needed for the outgoing arguments up to the next
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// alignment boundary.
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unsigned Align = MF.getTarget().getFrameInfo()->getStackAlignment();
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Amount = (Amount+Align-1)/Align*Align;
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// Replace the pseudo instruction with a new instruction...
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unsigned Opc = Old->getOpcode();
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if (Opc == ARM::ADJCALLSTACKDOWN || Opc == ARM::tADJCALLSTACKDOWN) {
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emitSPUpdate(MBB, I, TII, dl, *this, -Amount);
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assert(Opc == ARM::ADJCALLSTACKUP || Opc == ARM::tADJCALLSTACKUP);
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emitSPUpdate(MBB, I, TII, dl, *this, Amount);
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/// emitThumbConstant - Emit a series of instructions to materialize a
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static void emitThumbConstant(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator &MBBI,
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unsigned DestReg, int Imm,
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const TargetInstrInfo &TII,
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const Thumb1RegisterInfo& MRI,
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bool isSub = Imm < 0;
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if (isSub) Imm = -Imm;
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int Chunk = (1 << 8) - 1;
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int ThisVal = (Imm > Chunk) ? Chunk : Imm;
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AddDefaultPred(AddDefaultT1CC(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8),
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emitThumbRegPlusImmediate(MBB, MBBI, DestReg, DestReg, Imm, TII, MRI, dl);
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const TargetInstrDesc &TID = TII.get(ARM::tRSB);
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AddDefaultPred(AddDefaultT1CC(BuildMI(MBB, MBBI, dl, TID, DestReg))
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.addReg(DestReg, RegState::Kill));
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static void removeOperands(MachineInstr &MI, unsigned i) {
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for (unsigned e = MI.getNumOperands(); i != e; ++i)
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MI.RemoveOperand(Op);
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int Thumb1RegisterInfo::
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rewriteFrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
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unsigned FrameReg, int Offset,
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unsigned MOVOpc, unsigned ADDriOpc, unsigned SUBriOpc) const
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// if/when eliminateFrameIndex() conforms with ARMBaseRegisterInfo
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// version then can pull out Thumb1 specific parts here
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/// saveScavengerRegister - Spill the register so it can be used by the
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/// register scavenger. Return true.
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Thumb1RegisterInfo::saveScavengerRegister(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator I,
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MachineBasicBlock::iterator &UseMI,
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const TargetRegisterClass *RC,
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unsigned Reg) const {
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// Thumb1 can't use the emergency spill slot on the stack because
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// ldr/str immediate offsets must be positive, and if we're referencing
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// off the frame pointer (if, for example, there are alloca() calls in
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// the function, the offset will be negative. Use R12 instead since that's
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// a call clobbered register that we know won't be used in Thumb1 mode.
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DebugLoc DL = DebugLoc::getUnknownLoc();
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BuildMI(MBB, I, DL, TII.get(ARM::tMOVtgpr2gpr)).
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addReg(ARM::R12, RegState::Define).addReg(Reg, RegState::Kill);
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// The UseMI is where we would like to restore the register. If there's
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// interference with R12 before then, however, we'll need to restore it
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// before that instead and adjust the UseMI.
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for (MachineBasicBlock::iterator II = I; !done && II != UseMI ; ++II) {
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// If this instruction affects R12, adjust our restore point.
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for (unsigned i = 0, e = II->getNumOperands(); i != e; ++i) {
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const MachineOperand &MO = II->getOperand(i);
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if (!MO.isReg() || MO.isUndef() || !MO.getReg() ||
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TargetRegisterInfo::isVirtualRegister(MO.getReg()))
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if (MO.getReg() == ARM::R12) {
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// Restore the register from R12
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BuildMI(MBB, UseMI, DL, TII.get(ARM::tMOVgpr2tgpr)).
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addReg(Reg, RegState::Define).addReg(ARM::R12, RegState::Kill);
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Thumb1RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
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int SPAdj, int *Value,
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RegScavenger *RS) const{
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MachineInstr &MI = *II;
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MachineBasicBlock &MBB = *MI.getParent();
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MachineFunction &MF = *MBB.getParent();
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ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
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DebugLoc dl = MI.getDebugLoc();
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while (!MI.getOperand(i).isFI()) {
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assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
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unsigned FrameReg = ARM::SP;
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int FrameIndex = MI.getOperand(i).getIndex();
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int Offset = MF.getFrameInfo()->getObjectOffset(FrameIndex) +
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MF.getFrameInfo()->getStackSize() + SPAdj;
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if (AFI->isGPRCalleeSavedArea1Frame(FrameIndex))
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Offset -= AFI->getGPRCalleeSavedArea1Offset();
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else if (AFI->isGPRCalleeSavedArea2Frame(FrameIndex))
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Offset -= AFI->getGPRCalleeSavedArea2Offset();
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else if (MF.getFrameInfo()->hasVarSizedObjects()) {
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assert(SPAdj == 0 && hasFP(MF) && "Unexpected");
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// There are alloca()'s in this function, must reference off the frame
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FrameReg = getFrameRegister(MF);
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Offset -= AFI->getFramePtrSpillOffset();
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unsigned Opcode = MI.getOpcode();
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const TargetInstrDesc &Desc = MI.getDesc();
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unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
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if (Opcode == ARM::tADDrSPi) {
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Offset += MI.getOperand(i+1).getImm();
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// Can't use tADDrSPi if it's based off the frame pointer.
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unsigned NumBits = 0;
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if (FrameReg != ARM::SP) {
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Opcode = ARM::tADDi3;
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MI.setDesc(TII.get(Opcode));
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assert((Offset & 3) == 0 &&
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"Thumb add/sub sp, #imm immediate must be multiple of 4!");
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if (Offset == 0 && getInstrPredicate(&MI, PredReg) == ARMCC::AL) {
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// Turn it into a move.
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MI.setDesc(TII.get(ARM::tMOVgpr2tgpr));
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MI.getOperand(i).ChangeToRegister(FrameReg, false);
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// Remove offset and remaining explicit predicate operands.
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do MI.RemoveOperand(i+1);
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while (MI.getNumOperands() > i+1 &&
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(!MI.getOperand(i+1).isReg() || !MI.getOperand(i+1).isImm()));
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// Common case: small offset, fits into instruction.
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unsigned Mask = (1 << NumBits) - 1;
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if (((Offset / Scale) & ~Mask) == 0) {
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// Replace the FrameIndex with sp / fp
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if (Opcode == ARM::tADDi3) {
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removeOperands(MI, i);
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MachineInstrBuilder MIB(&MI);
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AddDefaultPred(AddDefaultT1CC(MIB).addReg(FrameReg)
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.addImm(Offset / Scale));
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MI.getOperand(i).ChangeToRegister(FrameReg, false);
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MI.getOperand(i+1).ChangeToImmediate(Offset / Scale);
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unsigned DestReg = MI.getOperand(0).getReg();
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unsigned Bytes = (Offset > 0) ? Offset : -Offset;
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unsigned NumMIs = calcNumMI(Opcode, 0, Bytes, NumBits, Scale);
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// MI would expand into a large number of instructions. Don't try to
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// simplify the immediate.
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emitThumbRegPlusImmediate(MBB, II, DestReg, FrameReg, Offset, TII,
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// Translate r0 = add sp, imm to
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// r0 = add sp, 255*4
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// r0 = add r0, (imm - 255*4)
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if (Opcode == ARM::tADDi3) {
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removeOperands(MI, i);
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MachineInstrBuilder MIB(&MI);
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AddDefaultPred(AddDefaultT1CC(MIB).addReg(FrameReg).addImm(Mask));
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MI.getOperand(i).ChangeToRegister(FrameReg, false);
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MI.getOperand(i+1).ChangeToImmediate(Mask);
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Offset = (Offset - Mask * Scale);
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MachineBasicBlock::iterator NII = llvm::next(II);
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emitThumbRegPlusImmediate(MBB, NII, DestReg, DestReg, Offset, TII,
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// Translate r0 = add sp, -imm to
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// r0 = -imm (this is then translated into a series of instructons)
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emitThumbConstant(MBB, II, DestReg, Offset, TII, *this, dl);
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MI.setDesc(TII.get(ARM::tADDhirr));
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MI.getOperand(i).ChangeToRegister(DestReg, false, false, true);
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MI.getOperand(i+1).ChangeToRegister(FrameReg, false);
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if (Opcode == ARM::tADDi3) {
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MachineInstrBuilder MIB(&MI);
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unsigned NumBits = 0;
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case ARMII::AddrModeT1_s: {
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InstrOffs = MI.getOperand(ImmIdx).getImm();
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NumBits = (FrameReg == ARM::SP) ? 8 : 5;
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llvm_unreachable("Unsupported addressing mode!");
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Offset += InstrOffs * Scale;
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assert((Offset & (Scale-1)) == 0 && "Can't encode this offset!");
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// Common case: small offset, fits into instruction.
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MachineOperand &ImmOp = MI.getOperand(ImmIdx);
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int ImmedOffset = Offset / Scale;
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unsigned Mask = (1 << NumBits) - 1;
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if ((unsigned)Offset <= Mask * Scale) {
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// Replace the FrameIndex with sp
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MI.getOperand(i).ChangeToRegister(FrameReg, false);
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ImmOp.ChangeToImmediate(ImmedOffset);
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bool isThumSpillRestore = Opcode == ARM::tRestore || Opcode == ARM::tSpill;
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if (AddrMode == ARMII::AddrModeT1_s) {
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// Thumb tLDRspi, tSTRspi. These will change to instructions that use
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// a different base register.
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Mask = (1 << NumBits) - 1;
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// If this is a thumb spill / restore, we will be using a constpool load to
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// materialize the offset.
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if (AddrMode == ARMII::AddrModeT1_s && isThumSpillRestore)
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ImmOp.ChangeToImmediate(0);
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// Otherwise, it didn't fit. Pull in what we can to simplify the immed.
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ImmedOffset = ImmedOffset & Mask;
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ImmOp.ChangeToImmediate(ImmedOffset);
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Offset &= ~(Mask*Scale);
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// If we get here, the immediate doesn't fit into the instruction. We folded
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// as much as possible above, handle the rest, providing a register that is
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assert(Offset && "This code isn't needed if offset already handled!");
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// Remove predicate first.
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int PIdx = MI.findFirstPredOperandIdx();
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removeOperands(MI, PIdx);
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if (Desc.mayLoad()) {
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// Use the destination register to materialize sp + offset.
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unsigned TmpReg = MI.getOperand(0).getReg();
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if (Opcode == ARM::tRestore) {
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if (FrameReg == ARM::SP)
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emitThumbRegPlusImmInReg(MBB, II, TmpReg, FrameReg,
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Offset, false, TII, *this, dl);
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emitLoadConstPool(MBB, II, dl, TmpReg, 0, Offset);
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emitThumbRegPlusImmediate(MBB, II, TmpReg, FrameReg, Offset, TII,
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MI.setDesc(TII.get(ARM::tLDR));
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MI.getOperand(i).ChangeToRegister(TmpReg, false, false, true);
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// Use [reg, reg] addrmode.
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MI.addOperand(MachineOperand::CreateReg(FrameReg, false));
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else // tLDR has an extra register operand.
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MI.addOperand(MachineOperand::CreateReg(0, false));
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} else if (Desc.mayStore()) {
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VReg = MF.getRegInfo().createVirtualRegister(ARM::tGPRRegisterClass);
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assert (Value && "Frame index virtual allocated, but Value arg is NULL!");
644
if (Opcode == ARM::tSpill) {
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if (FrameReg == ARM::SP)
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emitThumbRegPlusImmInReg(MBB, II, VReg, FrameReg,
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Offset, false, TII, *this, dl);
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emitLoadConstPool(MBB, II, dl, VReg, 0, Offset);
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emitThumbRegPlusImmediate(MBB, II, VReg, FrameReg, Offset, TII,
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MI.setDesc(TII.get(ARM::tSTR));
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MI.getOperand(i).ChangeToRegister(VReg, false, false, true);
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if (UseRR) // Use [reg, reg] addrmode.
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MI.addOperand(MachineOperand::CreateReg(FrameReg, false));
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else // tSTR has an extra register operand.
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MI.addOperand(MachineOperand::CreateReg(0, false));
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assert(false && "Unexpected opcode!");
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// Add predicate back if it's needed.
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if (MI.getDesc().isPredicable()) {
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MachineInstrBuilder MIB(&MI);
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void Thumb1RegisterInfo::emitPrologue(MachineFunction &MF) const {
673
MachineBasicBlock &MBB = MF.front();
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MachineBasicBlock::iterator MBBI = MBB.begin();
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MachineFrameInfo *MFI = MF.getFrameInfo();
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ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
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unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
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unsigned NumBytes = MFI->getStackSize();
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const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
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DebugLoc dl = (MBBI != MBB.end() ?
681
MBBI->getDebugLoc() : DebugLoc::getUnknownLoc());
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// Thumb add/sub sp, imm8 instructions implicitly multiply the offset by 4.
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NumBytes = (NumBytes + 3) & ~3;
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MFI->setStackSize(NumBytes);
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// Determine the sizes of each callee-save spill areas and record which frame
688
// belongs to which callee-save spill areas.
689
unsigned GPRCS1Size = 0, GPRCS2Size = 0, DPRCSSize = 0;
690
int FramePtrSpillFI = 0;
693
emitSPUpdate(MBB, MBBI, TII, dl, *this, -VARegSaveSize);
695
if (!AFI->hasStackFrame()) {
697
emitSPUpdate(MBB, MBBI, TII, dl, *this, -NumBytes);
701
for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
702
unsigned Reg = CSI[i].getReg();
703
int FI = CSI[i].getFrameIdx();
711
FramePtrSpillFI = FI;
712
AFI->addGPRCalleeSavedArea1Frame(FI);
720
FramePtrSpillFI = FI;
721
if (STI.isTargetDarwin()) {
722
AFI->addGPRCalleeSavedArea2Frame(FI);
725
AFI->addGPRCalleeSavedArea1Frame(FI);
730
AFI->addDPRCalleeSavedAreaFrame(FI);
735
if (MBBI != MBB.end() && MBBI->getOpcode() == ARM::tPUSH) {
737
if (MBBI != MBB.end())
738
dl = MBBI->getDebugLoc();
741
// Darwin ABI requires FP to point to the stack slot that contains the
743
if (STI.isTargetDarwin() || hasFP(MF)) {
744
BuildMI(MBB, MBBI, dl, TII.get(ARM::tADDrSPi), FramePtr)
745
.addFrameIndex(FramePtrSpillFI).addImm(0);
748
// Determine starting offsets of spill areas.
749
unsigned DPRCSOffset = NumBytes - (GPRCS1Size + GPRCS2Size + DPRCSSize);
750
unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize;
751
unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size;
752
AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) + NumBytes);
753
AFI->setGPRCalleeSavedArea1Offset(GPRCS1Offset);
754
AFI->setGPRCalleeSavedArea2Offset(GPRCS2Offset);
755
AFI->setDPRCalleeSavedAreaOffset(DPRCSOffset);
757
NumBytes = DPRCSOffset;
759
// Insert it after all the callee-save spills.
760
emitSPUpdate(MBB, MBBI, TII, dl, *this, -NumBytes);
763
if (STI.isTargetELF() && hasFP(MF)) {
764
MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() -
765
AFI->getFramePtrSpillOffset());
768
AFI->setGPRCalleeSavedArea1Size(GPRCS1Size);
769
AFI->setGPRCalleeSavedArea2Size(GPRCS2Size);
770
AFI->setDPRCalleeSavedAreaSize(DPRCSSize);
773
static bool isCalleeSavedRegister(unsigned Reg, const unsigned *CSRegs) {
774
for (unsigned i = 0; CSRegs[i]; ++i)
775
if (Reg == CSRegs[i])
780
static bool isCSRestore(MachineInstr *MI, const unsigned *CSRegs) {
781
if (MI->getOpcode() == ARM::tRestore &&
782
MI->getOperand(1).isFI() &&
783
isCalleeSavedRegister(MI->getOperand(0).getReg(), CSRegs))
785
else if (MI->getOpcode() == ARM::tPOP) {
786
// The first three operands are predicates and such. The last two are
787
// imp-def and imp-use of SP. Check everything in between.
788
for (int i = 3, e = MI->getNumOperands() - 2; i != e; ++i)
789
if (!isCalleeSavedRegister(MI->getOperand(i).getReg(), CSRegs))
796
void Thumb1RegisterInfo::emitEpilogue(MachineFunction &MF,
797
MachineBasicBlock &MBB) const {
798
MachineBasicBlock::iterator MBBI = prior(MBB.end());
799
assert((MBBI->getOpcode() == ARM::tBX_RET ||
800
MBBI->getOpcode() == ARM::tPOP_RET) &&
801
"Can only insert epilog into returning blocks");
802
DebugLoc dl = MBBI->getDebugLoc();
803
MachineFrameInfo *MFI = MF.getFrameInfo();
804
ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
805
unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
806
int NumBytes = (int)MFI->getStackSize();
807
const unsigned *CSRegs = getCalleeSavedRegs();
809
if (!AFI->hasStackFrame()) {
811
emitSPUpdate(MBB, MBBI, TII, dl, *this, NumBytes);
813
// Unwind MBBI to point to first LDR / VLDRD.
814
if (MBBI != MBB.begin()) {
817
while (MBBI != MBB.begin() && isCSRestore(MBBI, CSRegs));
818
if (!isCSRestore(MBBI, CSRegs))
822
// Move SP to start of FP callee save spill area.
823
NumBytes -= (AFI->getGPRCalleeSavedArea1Size() +
824
AFI->getGPRCalleeSavedArea2Size() +
825
AFI->getDPRCalleeSavedAreaSize());
828
NumBytes = AFI->getFramePtrSpillOffset() - NumBytes;
829
// Reset SP based on frame pointer only if the stack frame extends beyond
830
// frame pointer stack slot or target is ELF and the function has FP.
832
emitThumbRegPlusImmediate(MBB, MBBI, ARM::SP, FramePtr, -NumBytes,
835
BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVtgpr2gpr), ARM::SP)
838
if (MBBI->getOpcode() == ARM::tBX_RET &&
839
&MBB.front() != MBBI &&
840
prior(MBBI)->getOpcode() == ARM::tPOP) {
841
MachineBasicBlock::iterator PMBBI = prior(MBBI);
842
emitSPUpdate(MBB, PMBBI, TII, dl, *this, NumBytes);
844
emitSPUpdate(MBB, MBBI, TII, dl, *this, NumBytes);
849
// Move back past the callee-saved register restoration
850
while (MBBI != MBB.end() && isCSRestore(MBBI, CSRegs))
852
// Epilogue for vararg functions: pop LR to R3 and branch off it.
853
AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tPOP)))
854
.addReg(0) // No write back.
855
.addReg(ARM::R3, RegState::Define);
857
emitSPUpdate(MBB, MBBI, TII, dl, *this, VARegSaveSize);
859
BuildMI(MBB, MBBI, dl, TII.get(ARM::tBX_RET_vararg))
860
.addReg(ARM::R3, RegState::Kill);
861
// erase the old tBX_RET instruction