//===-- Mips16InstrInfo.cpp - Mips16 Instruction Information --------------===//
//
//                     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 Mips16 implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//

#include "Mips16InstrInfo.h"
#include "MipsTargetMachine.h"
#include "MipsMachineFunction.h"
#include "InstPrinter/MipsInstPrinter.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringRef.h"

using namespace llvm;

Mips16InstrInfo::Mips16InstrInfo(MipsTargetMachine &tm)
  : MipsInstrInfo(tm, /* FIXME: set mips16 unconditional br */ 0),
    RI(*tm.getSubtargetImpl()) {}

const MipsRegisterInfo &Mips16InstrInfo::getRegisterInfo() const {
  return RI;
}

/// 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 Mips16InstrInfo::
isLoadFromStackSlot(const MachineInstr *MI, int &FrameIndex) const
{
  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 Mips16InstrInfo::
isStoreToStackSlot(const MachineInstr *MI, int &FrameIndex) const
{
  return 0;
}

void Mips16InstrInfo::copyPhysReg(MachineBasicBlock &MBB,
                                  MachineBasicBlock::iterator I, DebugLoc DL,
                                  unsigned DestReg, unsigned SrcReg,
                                  bool KillSrc) const {
  unsigned Opc = 0, ZeroReg = 0;

  if (Mips::CPURegsRegClass.contains(DestReg)) { // Copy to CPU Reg.
    if (Mips::CPURegsRegClass.contains(SrcReg))
      Opc = Mips::Mov32R16;
  }

  assert(Opc && "Cannot copy registers");

  MachineInstrBuilder MIB = BuildMI(MBB, I, DL, get(Opc));

  if (DestReg)
    MIB.addReg(DestReg, RegState::Define);

  if (ZeroReg)
    MIB.addReg(ZeroReg);

  if (SrcReg)
    MIB.addReg(SrcReg, getKillRegState(KillSrc));
}

void Mips16InstrInfo::
storeRegToStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
                    unsigned SrcReg, bool isKill, int FI,
                    const TargetRegisterClass *RC,
                    const TargetRegisterInfo *TRI) const {
  assert(false && "Implement this function.");
}

void Mips16InstrInfo::
loadRegFromStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
                     unsigned DestReg, int FI,
                     const TargetRegisterClass *RC,
                     const TargetRegisterInfo *TRI) const {
  assert(false && "Implement this function.");
}

bool Mips16InstrInfo::expandPostRAPseudo(MachineBasicBlock::iterator MI) const {
  MachineBasicBlock &MBB = *MI->getParent();

  switch(MI->getDesc().getOpcode()) {
  default:
    return false;
  case Mips::RetRA16:
    ExpandRetRA16(MBB, MI, Mips::JrRa16);
    break;
  }

  MBB.erase(MI);
  return true;
}

/// GetOppositeBranchOpc - Return the inverse of the specified
/// opcode, e.g. turning BEQ to BNE.
unsigned Mips16InstrInfo::GetOppositeBranchOpc(unsigned Opc) const {
  assert(false && "Implement this function.");
  return 0;
}

unsigned Mips16InstrInfo::GetAnalyzableBrOpc(unsigned Opc) const {
  return 0;
}

void Mips16InstrInfo::ExpandRetRA16(MachineBasicBlock &MBB,
                                  MachineBasicBlock::iterator I,
                                  unsigned Opc) const {
  BuildMI(MBB, I, I->getDebugLoc(), get(Opc));
}

const MipsInstrInfo *llvm::createMips16InstrInfo(MipsTargetMachine &TM) {
  return new Mips16InstrInfo(TM);
}