//===- SparcInstrInfo.cpp - Sparc Instruction Information -------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the Sparc implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//

#include "SparcInstrInfo.h"
#include "SparcSubtarget.h"
#include "Sparc.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Support/ErrorHandling.h"
#include "SparcGenInstrInfo.inc"
#include "SparcMachineFunctionInfo.h"
using namespace llvm;

SparcInstrInfo::SparcInstrInfo(SparcSubtarget &ST)
  : TargetInstrInfoImpl(SparcInsts, array_lengthof(SparcInsts)),
    RI(ST, *this), Subtarget(ST) {
}

static bool isZeroImm(const MachineOperand &op) {
  return op.isImm() && op.getImm() == 0;
}

/// Return true if the instruction is a register to register move and
/// leave the source and dest operands in the passed parameters.
///
bool SparcInstrInfo::isMoveInstr(const MachineInstr &MI,
                                 unsigned &SrcReg, unsigned &DstReg,
                                 unsigned &SrcSR, unsigned &DstSR) const {
  SrcSR = DstSR = 0; // No sub-registers.

  // We look for 3 kinds of patterns here:
  // or with G0 or 0
  // add with G0 or 0
  // fmovs or FpMOVD (pseudo double move).
  if (MI.getOpcode() == SP::ORrr || MI.getOpcode() == SP::ADDrr) {
    if (MI.getOperand(1).getReg() == SP::G0) {
      DstReg = MI.getOperand(0).getReg();
      SrcReg = MI.getOperand(2).getReg();
      return true;
    } else if (MI.getOperand(2).getReg() == SP::G0) {
      DstReg = MI.getOperand(0).getReg();
      SrcReg = MI.getOperand(1).getReg();
      return true;
    }
  } else if ((MI.getOpcode() == SP::ORri || MI.getOpcode() == SP::ADDri) &&
             isZeroImm(MI.getOperand(2)) && MI.getOperand(1).isReg()) {
    DstReg = MI.getOperand(0).getReg();
    SrcReg = MI.getOperand(1).getReg();
    return true;
  } else if (MI.getOpcode() == SP::FMOVS || MI.getOpcode() == SP::FpMOVD ||
             MI.getOpcode() == SP::FMOVD) {
    SrcReg = MI.getOperand(1).getReg();
    DstReg = MI.getOperand(0).getReg();
    return true;
  }
  return false;
}

/// isLoadFromStackSlot - If the specified machine instruction is a direct
/// load from a stack slot, return the virtual or physical register number of
/// the destination along with the FrameIndex of the loaded stack slot.  If
/// not, return 0.  This predicate must return 0 if the instruction has
/// any side effects other than loading from the stack slot.
unsigned SparcInstrInfo::isLoadFromStackSlot(const MachineInstr *MI,
                                             int &FrameIndex) const {
  if (MI->getOpcode() == SP::LDri ||
      MI->getOpcode() == SP::LDFri ||
      MI->getOpcode() == SP::LDDFri) {
    if (MI->getOperand(1).isFI() && MI->getOperand(2).isImm() &&
        MI->getOperand(2).getImm() == 0) {
      FrameIndex = MI->getOperand(1).getIndex();
      return MI->getOperand(0).getReg();
    }
  }
  return 0;
}

/// isStoreToStackSlot - If the specified machine instruction is a direct
/// store to a stack slot, return the virtual or physical register number of
/// the source reg along with the FrameIndex of the loaded stack slot.  If
/// not, return 0.  This predicate must return 0 if the instruction has
/// any side effects other than storing to the stack slot.
unsigned SparcInstrInfo::isStoreToStackSlot(const MachineInstr *MI,
                                            int &FrameIndex) const {
  if (MI->getOpcode() == SP::STri ||
      MI->getOpcode() == SP::STFri ||
      MI->getOpcode() == SP::STDFri) {
    if (MI->getOperand(0).isFI() && MI->getOperand(1).isImm() &&
        MI->getOperand(1).getImm() == 0) {
      FrameIndex = MI->getOperand(0).getIndex();
      return MI->getOperand(2).getReg();
    }
  }
  return 0;
}

unsigned
SparcInstrInfo::InsertBranch(MachineBasicBlock &MBB,MachineBasicBlock *TBB,
                             MachineBasicBlock *FBB,
                             const SmallVectorImpl<MachineOperand> &Cond)const{
  // FIXME this should probably take a DebugLoc argument
  DebugLoc dl = DebugLoc::getUnknownLoc();
  // Can only insert uncond branches so far.
  assert(Cond.empty() && !FBB && TBB && "Can only handle uncond branches!");
  BuildMI(&MBB, dl, get(SP::BA)).addMBB(TBB);
  return 1;
}

bool SparcInstrInfo::copyRegToReg(MachineBasicBlock &MBB,
                                  MachineBasicBlock::iterator I,
                                  unsigned DestReg, unsigned SrcReg,
                                  const TargetRegisterClass *DestRC,
                                  const TargetRegisterClass *SrcRC) const {
  if (DestRC != SrcRC) {
    // Not yet supported!
    return false;
  }

  DebugLoc DL = DebugLoc::getUnknownLoc();
  if (I != MBB.end()) DL = I->getDebugLoc();

  if (DestRC == SP::IntRegsRegisterClass)
    BuildMI(MBB, I, DL, get(SP::ORrr), DestReg).addReg(SP::G0).addReg(SrcReg);
  else if (DestRC == SP::FPRegsRegisterClass)
    BuildMI(MBB, I, DL, get(SP::FMOVS), DestReg).addReg(SrcReg);
  else if (DestRC == SP::DFPRegsRegisterClass)
    BuildMI(MBB, I, DL, get(Subtarget.isV9() ? SP::FMOVD : SP::FpMOVD),DestReg)
      .addReg(SrcReg);
  else
    // Can't copy this register
    return false;

  return true;
}

void SparcInstrInfo::
storeRegToStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
                    unsigned SrcReg, bool isKill, int FI,
                    const TargetRegisterClass *RC) const {
  DebugLoc DL = DebugLoc::getUnknownLoc();
  if (I != MBB.end()) DL = I->getDebugLoc();

  // On the order of operands here: think "[FrameIdx + 0] = SrcReg".
  if (RC == SP::IntRegsRegisterClass)
    BuildMI(MBB, I, DL, get(SP::STri)).addFrameIndex(FI).addImm(0)
      .addReg(SrcReg, getKillRegState(isKill));
  else if (RC == SP::FPRegsRegisterClass)
    BuildMI(MBB, I, DL, get(SP::STFri)).addFrameIndex(FI).addImm(0)
      .addReg(SrcReg,  getKillRegState(isKill));
  else if (RC == SP::DFPRegsRegisterClass)
    BuildMI(MBB, I, DL, get(SP::STDFri)).addFrameIndex(FI).addImm(0)
      .addReg(SrcReg,  getKillRegState(isKill));
  else
    llvm_unreachable("Can't store this register to stack slot");
}

void SparcInstrInfo::
loadRegFromStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
                     unsigned DestReg, int FI,
                     const TargetRegisterClass *RC) const {
  DebugLoc DL = DebugLoc::getUnknownLoc();
  if (I != MBB.end()) DL = I->getDebugLoc();

  if (RC == SP::IntRegsRegisterClass)
    BuildMI(MBB, I, DL, get(SP::LDri), DestReg).addFrameIndex(FI).addImm(0);
  else if (RC == SP::FPRegsRegisterClass)
    BuildMI(MBB, I, DL, get(SP::LDFri), DestReg).addFrameIndex(FI).addImm(0);
  else if (RC == SP::DFPRegsRegisterClass)
    BuildMI(MBB, I, DL, get(SP::LDDFri), DestReg).addFrameIndex(FI).addImm(0);
  else
    llvm_unreachable("Can't load this register from stack slot");
}

MachineInstr *SparcInstrInfo::foldMemoryOperandImpl(MachineFunction &MF,
                                                    MachineInstr* MI,
                                          const SmallVectorImpl<unsigned> &Ops,
                                                    int FI) const {
  if (Ops.size() != 1) return NULL;

  unsigned OpNum = Ops[0];
  bool isFloat = false;
  MachineInstr *NewMI = NULL;
  switch (MI->getOpcode()) {
  case SP::ORrr:
    if (MI->getOperand(1).isReg() && MI->getOperand(1).getReg() == SP::G0&&
        MI->getOperand(0).isReg() && MI->getOperand(2).isReg()) {
      if (OpNum == 0)    // COPY -> STORE
        NewMI = BuildMI(MF, MI->getDebugLoc(), get(SP::STri))
          .addFrameIndex(FI)
          .addImm(0)
          .addReg(MI->getOperand(2).getReg());
      else               // COPY -> LOAD
        NewMI = BuildMI(MF, MI->getDebugLoc(), get(SP::LDri),
                        MI->getOperand(0).getReg())
          .addFrameIndex(FI)
          .addImm(0);
    }
    break;
  case SP::FMOVS:
    isFloat = true;
    // FALLTHROUGH
  case SP::FMOVD:
    if (OpNum == 0) { // COPY -> STORE
      unsigned SrcReg = MI->getOperand(1).getReg();
      bool isKill = MI->getOperand(1).isKill();
      bool isUndef = MI->getOperand(1).isUndef();
      NewMI = BuildMI(MF, MI->getDebugLoc(),
                      get(isFloat ? SP::STFri : SP::STDFri))
        .addFrameIndex(FI)
        .addImm(0)
        .addReg(SrcReg, getKillRegState(isKill) | getUndefRegState(isUndef));
    } else {             // COPY -> LOAD
      unsigned DstReg = MI->getOperand(0).getReg();
      bool isDead = MI->getOperand(0).isDead();
      bool isUndef = MI->getOperand(0).isUndef();
      NewMI = BuildMI(MF, MI->getDebugLoc(),
                      get(isFloat ? SP::LDFri : SP::LDDFri))
        .addReg(DstReg, RegState::Define |
                getDeadRegState(isDead) | getUndefRegState(isUndef))
        .addFrameIndex(FI)
        .addImm(0);
    }
    break;
  }

  return NewMI;
}

unsigned SparcInstrInfo::getGlobalBaseReg(MachineFunction *MF) const
{
  SparcMachineFunctionInfo *SparcFI = MF->getInfo<SparcMachineFunctionInfo>();
  unsigned GlobalBaseReg = SparcFI->getGlobalBaseReg();
  if (GlobalBaseReg != 0)
    return GlobalBaseReg;

  // Insert the set of GlobalBaseReg into the first MBB of the function
  MachineBasicBlock &FirstMBB = MF->front();
  MachineBasicBlock::iterator MBBI = FirstMBB.begin();
  MachineRegisterInfo &RegInfo = MF->getRegInfo();

  GlobalBaseReg = RegInfo.createVirtualRegister(&SP::IntRegsRegClass);


  DebugLoc dl = DebugLoc::getUnknownLoc();

  BuildMI(FirstMBB, MBBI, dl, get(SP::GETPCX), GlobalBaseReg);
  SparcFI->setGlobalBaseReg(GlobalBaseReg);
  return GlobalBaseReg;
}