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      1 //===-- MipsMCInstLower.cpp - Convert Mips MachineInstr to MCInst ---------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file contains code to lower Mips MachineInstrs to their corresponding
     11 // MCInst records.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 #include "MipsMCInstLower.h"
     15 #include "MCTargetDesc/MipsBaseInfo.h"
     16 #include "MipsAsmPrinter.h"
     17 #include "MipsInstrInfo.h"
     18 #include "llvm/CodeGen/MachineFunction.h"
     19 #include "llvm/CodeGen/MachineInstr.h"
     20 #include "llvm/CodeGen/MachineOperand.h"
     21 #include "llvm/MC/MCContext.h"
     22 #include "llvm/MC/MCExpr.h"
     23 #include "llvm/MC/MCInst.h"
     24 #include "llvm/Target/Mangler.h"
     25 
     26 using namespace llvm;
     27 
     28 MipsMCInstLower::MipsMCInstLower(MipsAsmPrinter &asmprinter)
     29   : AsmPrinter(asmprinter) {}
     30 
     31 void MipsMCInstLower::Initialize(Mangler *M, MCContext *C) {
     32   Mang = M;
     33   Ctx = C;
     34 }
     35 
     36 MCOperand MipsMCInstLower::LowerSymbolOperand(const MachineOperand &MO,
     37                                               MachineOperandType MOTy,
     38                                               unsigned Offset) const {
     39   MCSymbolRefExpr::VariantKind Kind;
     40   const MCSymbol *Symbol;
     41 
     42   switch(MO.getTargetFlags()) {
     43   default:                   llvm_unreachable("Invalid target flag!");
     44   case MipsII::MO_NO_FLAG:   Kind = MCSymbolRefExpr::VK_None; break;
     45   case MipsII::MO_GPREL:     Kind = MCSymbolRefExpr::VK_Mips_GPREL; break;
     46   case MipsII::MO_GOT_CALL:  Kind = MCSymbolRefExpr::VK_Mips_GOT_CALL; break;
     47   case MipsII::MO_GOT16:     Kind = MCSymbolRefExpr::VK_Mips_GOT16; break;
     48   case MipsII::MO_GOT:       Kind = MCSymbolRefExpr::VK_Mips_GOT; break;
     49   case MipsII::MO_ABS_HI:    Kind = MCSymbolRefExpr::VK_Mips_ABS_HI; break;
     50   case MipsII::MO_ABS_LO:    Kind = MCSymbolRefExpr::VK_Mips_ABS_LO; break;
     51   case MipsII::MO_TLSGD:     Kind = MCSymbolRefExpr::VK_Mips_TLSGD; break;
     52   case MipsII::MO_TLSLDM:    Kind = MCSymbolRefExpr::VK_Mips_TLSLDM; break;
     53   case MipsII::MO_DTPREL_HI: Kind = MCSymbolRefExpr::VK_Mips_DTPREL_HI; break;
     54   case MipsII::MO_DTPREL_LO: Kind = MCSymbolRefExpr::VK_Mips_DTPREL_LO; break;
     55   case MipsII::MO_GOTTPREL:  Kind = MCSymbolRefExpr::VK_Mips_GOTTPREL; break;
     56   case MipsII::MO_TPREL_HI:  Kind = MCSymbolRefExpr::VK_Mips_TPREL_HI; break;
     57   case MipsII::MO_TPREL_LO:  Kind = MCSymbolRefExpr::VK_Mips_TPREL_LO; break;
     58   case MipsII::MO_GPOFF_HI:  Kind = MCSymbolRefExpr::VK_Mips_GPOFF_HI; break;
     59   case MipsII::MO_GPOFF_LO:  Kind = MCSymbolRefExpr::VK_Mips_GPOFF_LO; break;
     60   case MipsII::MO_GOT_DISP:  Kind = MCSymbolRefExpr::VK_Mips_GOT_DISP; break;
     61   case MipsII::MO_GOT_PAGE:  Kind = MCSymbolRefExpr::VK_Mips_GOT_PAGE; break;
     62   case MipsII::MO_GOT_OFST:  Kind = MCSymbolRefExpr::VK_Mips_GOT_OFST; break;
     63   case MipsII::MO_HIGHER:    Kind = MCSymbolRefExpr::VK_Mips_HIGHER; break;
     64   case MipsII::MO_HIGHEST:   Kind = MCSymbolRefExpr::VK_Mips_HIGHEST; break;
     65   case MipsII::MO_GOT_HI16:  Kind = MCSymbolRefExpr::VK_Mips_GOT_HI16; break;
     66   case MipsII::MO_GOT_LO16:  Kind = MCSymbolRefExpr::VK_Mips_GOT_LO16; break;
     67   case MipsII::MO_CALL_HI16: Kind = MCSymbolRefExpr::VK_Mips_CALL_HI16; break;
     68   case MipsII::MO_CALL_LO16: Kind = MCSymbolRefExpr::VK_Mips_CALL_LO16; break;
     69   }
     70 
     71   switch (MOTy) {
     72   case MachineOperand::MO_MachineBasicBlock:
     73     Symbol = MO.getMBB()->getSymbol();
     74     break;
     75 
     76   case MachineOperand::MO_GlobalAddress:
     77     Symbol = Mang->getSymbol(MO.getGlobal());
     78     Offset += MO.getOffset();
     79     break;
     80 
     81   case MachineOperand::MO_BlockAddress:
     82     Symbol = AsmPrinter.GetBlockAddressSymbol(MO.getBlockAddress());
     83     Offset += MO.getOffset();
     84     break;
     85 
     86   case MachineOperand::MO_ExternalSymbol:
     87     Symbol = AsmPrinter.GetExternalSymbolSymbol(MO.getSymbolName());
     88     Offset += MO.getOffset();
     89     break;
     90 
     91   case MachineOperand::MO_JumpTableIndex:
     92     Symbol = AsmPrinter.GetJTISymbol(MO.getIndex());
     93     break;
     94 
     95   case MachineOperand::MO_ConstantPoolIndex:
     96     Symbol = AsmPrinter.GetCPISymbol(MO.getIndex());
     97     Offset += MO.getOffset();
     98     break;
     99 
    100   default:
    101     llvm_unreachable("<unknown operand type>");
    102   }
    103 
    104   const MCSymbolRefExpr *MCSym = MCSymbolRefExpr::Create(Symbol, Kind, *Ctx);
    105 
    106   if (!Offset)
    107     return MCOperand::CreateExpr(MCSym);
    108 
    109   // Assume offset is never negative.
    110   assert(Offset > 0);
    111 
    112   const MCConstantExpr *OffsetExpr =  MCConstantExpr::Create(Offset, *Ctx);
    113   const MCBinaryExpr *Add = MCBinaryExpr::CreateAdd(MCSym, OffsetExpr, *Ctx);
    114   return MCOperand::CreateExpr(Add);
    115 }
    116 
    117 /*
    118 static void CreateMCInst(MCInst& Inst, unsigned Opc, const MCOperand &Opnd0,
    119                          const MCOperand &Opnd1,
    120                          const MCOperand &Opnd2 = MCOperand()) {
    121   Inst.setOpcode(Opc);
    122   Inst.addOperand(Opnd0);
    123   Inst.addOperand(Opnd1);
    124   if (Opnd2.isValid())
    125     Inst.addOperand(Opnd2);
    126 }
    127 */
    128 
    129 MCOperand MipsMCInstLower::LowerOperand(const MachineOperand &MO,
    130                                         unsigned offset) const {
    131   MachineOperandType MOTy = MO.getType();
    132 
    133   switch (MOTy) {
    134   default: llvm_unreachable("unknown operand type");
    135   case MachineOperand::MO_Register:
    136     // Ignore all implicit register operands.
    137     if (MO.isImplicit()) break;
    138     return MCOperand::CreateReg(MO.getReg());
    139   case MachineOperand::MO_Immediate:
    140     return MCOperand::CreateImm(MO.getImm() + offset);
    141   case MachineOperand::MO_MachineBasicBlock:
    142   case MachineOperand::MO_GlobalAddress:
    143   case MachineOperand::MO_ExternalSymbol:
    144   case MachineOperand::MO_JumpTableIndex:
    145   case MachineOperand::MO_ConstantPoolIndex:
    146   case MachineOperand::MO_BlockAddress:
    147     return LowerSymbolOperand(MO, MOTy, offset);
    148   case MachineOperand::MO_RegisterMask:
    149     break;
    150  }
    151 
    152   return MCOperand();
    153 }
    154 
    155 void MipsMCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const {
    156   OutMI.setOpcode(MI->getOpcode());
    157 
    158   for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
    159     const MachineOperand &MO = MI->getOperand(i);
    160     MCOperand MCOp = LowerOperand(MO);
    161 
    162     if (MCOp.isValid())
    163       OutMI.addOperand(MCOp);
    164   }
    165 }
    166 
    167