llvm-project/llvm/lib/Target/Mips/MipsMCInstLower.cpp

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C++

//===-- MipsMCInstLower.cpp - Convert Mips MachineInstr to MCInst ---------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains code to lower Mips MachineInstrs to their corresponding
// MCInst records.
//
//===----------------------------------------------------------------------===//
#include "MipsAsmPrinter.h"
#include "MipsInstrInfo.h"
#include "MipsMCInstLower.h"
#include "MCTargetDesc/MipsBaseInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/Target/Mangler.h"
using namespace llvm;
MipsMCInstLower::MipsMCInstLower(Mangler *mang, const MachineFunction &mf,
MipsAsmPrinter &asmprinter)
: Ctx(mf.getContext()), Mang(mang), AsmPrinter(asmprinter) {}
MCOperand MipsMCInstLower::LowerSymbolOperand(const MachineOperand &MO,
MachineOperandType MOTy,
unsigned Offset) const {
MCSymbolRefExpr::VariantKind Kind;
const MCSymbol *Symbol;
switch(MO.getTargetFlags()) {
default: llvm_unreachable("Invalid target flag!");
case MipsII::MO_NO_FLAG: Kind = MCSymbolRefExpr::VK_None; break;
case MipsII::MO_GPREL: Kind = MCSymbolRefExpr::VK_Mips_GPREL; break;
case MipsII::MO_GOT_CALL: Kind = MCSymbolRefExpr::VK_Mips_GOT_CALL; break;
case MipsII::MO_GOT16: Kind = MCSymbolRefExpr::VK_Mips_GOT16; break;
case MipsII::MO_GOT: Kind = MCSymbolRefExpr::VK_Mips_GOT; break;
case MipsII::MO_ABS_HI: Kind = MCSymbolRefExpr::VK_Mips_ABS_HI; break;
case MipsII::MO_ABS_LO: Kind = MCSymbolRefExpr::VK_Mips_ABS_LO; break;
case MipsII::MO_TLSGD: Kind = MCSymbolRefExpr::VK_Mips_TLSGD; break;
case MipsII::MO_TLSLDM: Kind = MCSymbolRefExpr::VK_Mips_TLSLDM; break;
case MipsII::MO_DTPREL_HI: Kind = MCSymbolRefExpr::VK_Mips_DTPREL_HI; break;
case MipsII::MO_DTPREL_LO: Kind = MCSymbolRefExpr::VK_Mips_DTPREL_LO; break;
case MipsII::MO_GOTTPREL: Kind = MCSymbolRefExpr::VK_Mips_GOTTPREL; break;
case MipsII::MO_TPREL_HI: Kind = MCSymbolRefExpr::VK_Mips_TPREL_HI; break;
case MipsII::MO_TPREL_LO: Kind = MCSymbolRefExpr::VK_Mips_TPREL_LO; break;
case MipsII::MO_GPOFF_HI: Kind = MCSymbolRefExpr::VK_Mips_GPOFF_HI; break;
case MipsII::MO_GPOFF_LO: Kind = MCSymbolRefExpr::VK_Mips_GPOFF_LO; break;
case MipsII::MO_GOT_DISP: Kind = MCSymbolRefExpr::VK_Mips_GOT_DISP; break;
case MipsII::MO_GOT_PAGE: Kind = MCSymbolRefExpr::VK_Mips_GOT_PAGE; break;
case MipsII::MO_GOT_OFST: Kind = MCSymbolRefExpr::VK_Mips_GOT_OFST; break;
}
switch (MOTy) {
case MachineOperand::MO_MachineBasicBlock:
Symbol = MO.getMBB()->getSymbol();
break;
case MachineOperand::MO_GlobalAddress:
Symbol = Mang->getSymbol(MO.getGlobal());
break;
case MachineOperand::MO_BlockAddress:
Symbol = AsmPrinter.GetBlockAddressSymbol(MO.getBlockAddress());
break;
case MachineOperand::MO_ExternalSymbol:
Symbol = AsmPrinter.GetExternalSymbolSymbol(MO.getSymbolName());
break;
case MachineOperand::MO_JumpTableIndex:
Symbol = AsmPrinter.GetJTISymbol(MO.getIndex());
break;
case MachineOperand::MO_ConstantPoolIndex:
Symbol = AsmPrinter.GetCPISymbol(MO.getIndex());
if (MO.getOffset())
Offset += MO.getOffset();
break;
default:
llvm_unreachable("<unknown operand type>");
}
const MCSymbolRefExpr *MCSym = MCSymbolRefExpr::Create(Symbol, Kind, Ctx);
if (!Offset)
return MCOperand::CreateExpr(MCSym);
// Assume offset is never negative.
assert(Offset > 0);
const MCConstantExpr *OffsetExpr = MCConstantExpr::Create(Offset, Ctx);
const MCBinaryExpr *AddExpr = MCBinaryExpr::CreateAdd(MCSym, OffsetExpr, Ctx);
return MCOperand::CreateExpr(AddExpr);
}
// Lower ".cpload $reg" to
// "lui $gp, %hi(_gp_disp)"
// "addiu $gp, $gp, %lo(_gp_disp)"
// "addu $gp. $gp, $reg"
void MipsMCInstLower::LowerCPLOAD(const MachineInstr *MI,
SmallVector<MCInst, 4>& MCInsts) {
MCInst Lui, Addiu, Addu;
StringRef SymName("_gp_disp");
const MCSymbol *Symbol = Ctx.GetOrCreateSymbol(SymName);
const MCSymbolRefExpr *MCSym;
// lui $gp, %hi(_gp_disp)
Lui.setOpcode(Mips::LUi);
Lui.addOperand(MCOperand::CreateReg(Mips::GP));
MCSym = MCSymbolRefExpr::Create(Symbol, MCSymbolRefExpr::VK_Mips_ABS_HI, Ctx);
Lui.addOperand(MCOperand::CreateExpr(MCSym));
MCInsts.push_back(Lui);
// addiu $gp, $gp, %lo(_gp_disp)
Addiu.setOpcode(Mips::ADDiu);
Addiu.addOperand(MCOperand::CreateReg(Mips::GP));
Addiu.addOperand(MCOperand::CreateReg(Mips::GP));
MCSym = MCSymbolRefExpr::Create(Symbol, MCSymbolRefExpr::VK_Mips_ABS_LO, Ctx);
Addiu.addOperand(MCOperand::CreateExpr(MCSym));
MCInsts.push_back(Addiu);
// addu $gp. $gp, $reg
Addu.setOpcode(Mips::ADDu);
Addu.addOperand(MCOperand::CreateReg(Mips::GP));
Addu.addOperand(MCOperand::CreateReg(Mips::GP));
const MachineOperand &MO = MI->getOperand(0);
assert(MO.isReg() && "CPLOAD's operand must be a register.");
Addu.addOperand(MCOperand::CreateReg(MO.getReg()));
MCInsts.push_back(Addu);
}
// Lower ".cprestore offset" to "sw $gp, offset($sp)".
void MipsMCInstLower::LowerCPRESTORE(const MachineInstr *MI,
SmallVector<MCInst, 4>& MCInsts) {
const MachineOperand &MO = MI->getOperand(0);
assert(MO.isImm() && "CPRESTORE's operand must be an immediate.");
unsigned Offset = MO.getImm(), Reg = Mips::SP;
MCInst Sw;
if (Offset >= 0x8000) {
unsigned Hi = (Offset >> 16) + ((Offset & 0x8000) != 0);
Offset &= 0xffff;
Reg = Mips::AT;
// lui at,hi
// addu at,at,sp
MCInsts.resize(2);
MCInsts[0].setOpcode(Mips::LUi);
MCInsts[0].addOperand(MCOperand::CreateReg(Mips::AT));
MCInsts[0].addOperand(MCOperand::CreateImm(Hi));
MCInsts[1].setOpcode(Mips::ADDu);
MCInsts[1].addOperand(MCOperand::CreateReg(Mips::AT));
MCInsts[1].addOperand(MCOperand::CreateReg(Mips::AT));
MCInsts[1].addOperand(MCOperand::CreateReg(Mips::SP));
}
Sw.setOpcode(Mips::SW);
Sw.addOperand(MCOperand::CreateReg(Mips::GP));
Sw.addOperand(MCOperand::CreateReg(Reg));
Sw.addOperand(MCOperand::CreateImm(Offset));
MCInsts.push_back(Sw);
}
MCOperand MipsMCInstLower::LowerOperand(const MachineOperand& MO,
unsigned offset) const {
MachineOperandType MOTy = MO.getType();
switch (MOTy) {
default: llvm_unreachable("unknown operand type");
case MachineOperand::MO_Register:
// Ignore all implicit register operands.
if (MO.isImplicit()) break;
return MCOperand::CreateReg(MO.getReg());
case MachineOperand::MO_Immediate:
return MCOperand::CreateImm(MO.getImm() + offset);
case MachineOperand::MO_MachineBasicBlock:
case MachineOperand::MO_GlobalAddress:
case MachineOperand::MO_ExternalSymbol:
case MachineOperand::MO_JumpTableIndex:
case MachineOperand::MO_ConstantPoolIndex:
case MachineOperand::MO_BlockAddress:
return LowerSymbolOperand(MO, MOTy, offset);
case MachineOperand::MO_RegisterMask:
break;
}
return MCOperand();
}
void MipsMCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const {
OutMI.setOpcode(MI->getOpcode());
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI->getOperand(i);
MCOperand MCOp = LowerOperand(MO);
if (MCOp.isValid())
OutMI.addOperand(MCOp);
}
}
void MipsMCInstLower::LowerUnalignedLoadStore(const MachineInstr *MI,
SmallVector<MCInst,
4>& MCInsts) {
unsigned Opc = MI->getOpcode();
MCInst Instr1, Instr2, Instr3, Move;
bool TwoInstructions = false;
assert(MI->getNumOperands() == 3);
assert(MI->getOperand(0).isReg());
assert(MI->getOperand(1).isReg());
MCOperand Target = LowerOperand(MI->getOperand(0));
MCOperand Base = LowerOperand(MI->getOperand(1));
MCOperand ATReg = MCOperand::CreateReg(Mips::AT);
MCOperand ZeroReg = MCOperand::CreateReg(Mips::ZERO);
MachineOperand UnLoweredName = MI->getOperand(2);
MCOperand Name = LowerOperand(UnLoweredName);
Move.setOpcode(Mips::ADDu);
Move.addOperand(Target);
Move.addOperand(ATReg);
Move.addOperand(ZeroReg);
switch (Opc) {
case Mips::ULW: {
// FIXME: only works for little endian right now
MCOperand AdjName = LowerOperand(UnLoweredName, 3);
if (Base.getReg() == (Target.getReg())) {
Instr1.setOpcode(Mips::LWL);
Instr1.addOperand(ATReg);
Instr1.addOperand(Base);
Instr1.addOperand(AdjName);
Instr2.setOpcode(Mips::LWR);
Instr2.addOperand(ATReg);
Instr2.addOperand(Base);
Instr2.addOperand(Name);
Instr3 = Move;
} else {
TwoInstructions = true;
Instr1.setOpcode(Mips::LWL);
Instr1.addOperand(Target);
Instr1.addOperand(Base);
Instr1.addOperand(AdjName);
Instr2.setOpcode(Mips::LWR);
Instr2.addOperand(Target);
Instr2.addOperand(Base);
Instr2.addOperand(Name);
}
break;
}
case Mips::ULHu: {
// FIXME: only works for little endian right now
MCOperand AdjName = LowerOperand(UnLoweredName, 1);
Instr1.setOpcode(Mips::LBu);
Instr1.addOperand(ATReg);
Instr1.addOperand(Base);
Instr1.addOperand(AdjName);
Instr2.setOpcode(Mips::LBu);
Instr2.addOperand(Target);
Instr2.addOperand(Base);
Instr2.addOperand(Name);
Instr3.setOpcode(Mips::INS);
Instr3.addOperand(Target);
Instr3.addOperand(ATReg);
Instr3.addOperand(MCOperand::CreateImm(0x8));
Instr3.addOperand(MCOperand::CreateImm(0x18));
break;
}
case Mips::USW: {
// FIXME: only works for little endian right now
assert (Base.getReg() != Target.getReg());
TwoInstructions = true;
MCOperand AdjName = LowerOperand(UnLoweredName, 3);
Instr1.setOpcode(Mips::SWL);
Instr1.addOperand(Target);
Instr1.addOperand(Base);
Instr1.addOperand(AdjName);
Instr2.setOpcode(Mips::SWR);
Instr2.addOperand(Target);
Instr2.addOperand(Base);
Instr2.addOperand(Name);
break;
}
case Mips::USH: {
MCOperand AdjName = LowerOperand(UnLoweredName, 1);
Instr1.setOpcode(Mips::SB);
Instr1.addOperand(Target);
Instr1.addOperand(Base);
Instr1.addOperand(Name);
Instr2.setOpcode(Mips::SRL);
Instr2.addOperand(ATReg);
Instr2.addOperand(Target);
Instr2.addOperand(MCOperand::CreateImm(8));
Instr3.setOpcode(Mips::SB);
Instr3.addOperand(ATReg);
Instr3.addOperand(Base);
Instr3.addOperand(AdjName);
break;
}
default:
// FIXME: need to add others
llvm_unreachable("unaligned instruction not processed");
}
MCInsts.push_back(Instr1);
MCInsts.push_back(Instr2);
if (!TwoInstructions) MCInsts.push_back(Instr3);
}