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      1 //===-- MBlazeMCInstLower.cpp - Convert MBlaze MachineInstr to an 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 MBlaze MachineInstrs to their corresponding
     11 // MCInst records.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #include "MBlazeMCInstLower.h"
     16 #include "MBlazeInstrInfo.h"
     17 #include "llvm/ADT/SmallString.h"
     18 #include "llvm/CodeGen/AsmPrinter.h"
     19 #include "llvm/CodeGen/MachineBasicBlock.h"
     20 #include "llvm/CodeGen/MachineInstr.h"
     21 #include "llvm/IR/Constants.h"
     22 #include "llvm/MC/MCAsmInfo.h"
     23 #include "llvm/MC/MCContext.h"
     24 #include "llvm/MC/MCExpr.h"
     25 #include "llvm/MC/MCInst.h"
     26 #include "llvm/Support/Debug.h"
     27 #include "llvm/Support/ErrorHandling.h"
     28 #include "llvm/Support/raw_ostream.h"
     29 #include "llvm/Target/Mangler.h"
     30 using namespace llvm;
     31 
     32 MCSymbol *MBlazeMCInstLower::
     33 GetGlobalAddressSymbol(const MachineOperand &MO) const {
     34   switch (MO.getTargetFlags()) {
     35   default: llvm_unreachable("Unknown target flag on GV operand");
     36   case 0:  break;
     37   }
     38 
     39   return Printer.Mang->getSymbol(MO.getGlobal());
     40 }
     41 
     42 MCSymbol *MBlazeMCInstLower::
     43 GetExternalSymbolSymbol(const MachineOperand &MO) const {
     44   switch (MO.getTargetFlags()) {
     45   default: llvm_unreachable("Unknown target flag on GV operand");
     46   case 0:  break;
     47   }
     48 
     49   return Printer.GetExternalSymbolSymbol(MO.getSymbolName());
     50 }
     51 
     52 MCSymbol *MBlazeMCInstLower::
     53 GetJumpTableSymbol(const MachineOperand &MO) const {
     54   SmallString<256> Name;
     55   raw_svector_ostream(Name) << Printer.MAI->getPrivateGlobalPrefix() << "JTI"
     56                             << Printer.getFunctionNumber() << '_'
     57                             << MO.getIndex();
     58   switch (MO.getTargetFlags()) {
     59   default: llvm_unreachable("Unknown target flag on GV operand");
     60   case 0:  break;
     61   }
     62 
     63   // Create a symbol for the name.
     64   return Ctx.GetOrCreateSymbol(Name.str());
     65 }
     66 
     67 MCSymbol *MBlazeMCInstLower::
     68 GetConstantPoolIndexSymbol(const MachineOperand &MO) const {
     69   SmallString<256> Name;
     70   raw_svector_ostream(Name) << Printer.MAI->getPrivateGlobalPrefix() << "CPI"
     71                             << Printer.getFunctionNumber() << '_'
     72                             << MO.getIndex();
     73 
     74   switch (MO.getTargetFlags()) {
     75   default:
     76       llvm_unreachable("Unknown target flag on GV operand");
     77 
     78   case 0: break;
     79   }
     80 
     81   // Create a symbol for the name.
     82   return Ctx.GetOrCreateSymbol(Name.str());
     83 }
     84 
     85 MCSymbol *MBlazeMCInstLower::
     86 GetBlockAddressSymbol(const MachineOperand &MO) const {
     87   switch (MO.getTargetFlags()) {
     88   default: llvm_unreachable("Unknown target flag on GV operand");
     89   case 0: break;
     90   }
     91 
     92   return Printer.GetBlockAddressSymbol(MO.getBlockAddress());
     93 }
     94 
     95 MCOperand MBlazeMCInstLower::
     96 LowerSymbolOperand(const MachineOperand &MO, MCSymbol *Sym) const {
     97   // FIXME: We would like an efficient form for this, so we don't have to do a
     98   // lot of extra uniquing.
     99   const MCExpr *Expr = MCSymbolRefExpr::Create(Sym, Ctx);
    100 
    101   switch (MO.getTargetFlags()) {
    102   default:
    103       llvm_unreachable("Unknown target flag on GV operand");
    104 
    105   case 0: break;
    106   }
    107 
    108   if (!MO.isJTI() && MO.getOffset())
    109     Expr = MCBinaryExpr::CreateAdd(Expr,
    110                                    MCConstantExpr::Create(MO.getOffset(), Ctx),
    111                                    Ctx);
    112   return MCOperand::CreateExpr(Expr);
    113 }
    114 
    115 void MBlazeMCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const {
    116   OutMI.setOpcode(MI->getOpcode());
    117 
    118   for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
    119     const MachineOperand &MO = MI->getOperand(i);
    120 
    121     MCOperand MCOp;
    122     switch (MO.getType()) {
    123     default: llvm_unreachable("unknown operand type");
    124     case MachineOperand::MO_Register:
    125       // Ignore all implicit register operands.
    126       if (MO.isImplicit()) continue;
    127       MCOp = MCOperand::CreateReg(MO.getReg());
    128       break;
    129     case MachineOperand::MO_Immediate:
    130       MCOp = MCOperand::CreateImm(MO.getImm());
    131       break;
    132     case MachineOperand::MO_MachineBasicBlock:
    133       MCOp = MCOperand::CreateExpr(MCSymbolRefExpr::Create(
    134                          MO.getMBB()->getSymbol(), Ctx));
    135       break;
    136     case MachineOperand::MO_GlobalAddress:
    137       MCOp = LowerSymbolOperand(MO, GetGlobalAddressSymbol(MO));
    138       break;
    139     case MachineOperand::MO_ExternalSymbol:
    140       MCOp = LowerSymbolOperand(MO, GetExternalSymbolSymbol(MO));
    141       break;
    142     case MachineOperand::MO_JumpTableIndex:
    143       MCOp = LowerSymbolOperand(MO, GetJumpTableSymbol(MO));
    144       break;
    145     case MachineOperand::MO_ConstantPoolIndex:
    146       MCOp = LowerSymbolOperand(MO, GetConstantPoolIndexSymbol(MO));
    147       break;
    148     case MachineOperand::MO_BlockAddress:
    149       MCOp = LowerSymbolOperand(MO, GetBlockAddressSymbol(MO));
    150       break;
    151     case MachineOperand::MO_FPImmediate: {
    152       bool ignored;
    153       APFloat FVal = MO.getFPImm()->getValueAPF();
    154       FVal.convert(APFloat::IEEEsingle, APFloat::rmTowardZero, &ignored);
    155 
    156       APInt IVal = FVal.bitcastToAPInt();
    157       uint64_t Val = *IVal.getRawData();
    158       MCOp = MCOperand::CreateImm(Val);
    159       break;
    160     }
    161     case MachineOperand::MO_RegisterMask:
    162       continue;
    163     }
    164 
    165     OutMI.addOperand(MCOp);
    166   }
    167 }
    168