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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/Constants.h"
     18 #include "llvm/CodeGen/AsmPrinter.h"
     19 #include "llvm/CodeGen/MachineBasicBlock.h"
     20 #include "llvm/CodeGen/MachineInstr.h"
     21 #include "llvm/MC/MCAsmInfo.h"
     22 #include "llvm/MC/MCContext.h"
     23 #include "llvm/MC/MCExpr.h"
     24 #include "llvm/MC/MCInst.h"
     25 #include "llvm/Target/Mangler.h"
     26 #include "llvm/Support/Debug.h"
     27 #include "llvm/Support/raw_ostream.h"
     28 #include "llvm/Support/ErrorHandling.h"
     29 #include "llvm/ADT/SmallString.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:
     89       assert(0 && "Unknown target flag on GV operand");
     90 
     91   case 0: break;
     92   }
     93 
     94   return Printer.GetBlockAddressSymbol(MO.getBlockAddress());
     95 }
     96 
     97 MCOperand MBlazeMCInstLower::
     98 LowerSymbolOperand(const MachineOperand &MO, MCSymbol *Sym) const {
     99   // FIXME: We would like an efficient form for this, so we don't have to do a
    100   // lot of extra uniquing.
    101   const MCExpr *Expr = MCSymbolRefExpr::Create(Sym, Ctx);
    102 
    103   switch (MO.getTargetFlags()) {
    104   default:
    105       llvm_unreachable("Unknown target flag on GV operand");
    106 
    107   case 0: break;
    108   }
    109 
    110   if (!MO.isJTI() && MO.getOffset())
    111     Expr = MCBinaryExpr::CreateAdd(Expr,
    112                                    MCConstantExpr::Create(MO.getOffset(), Ctx),
    113                                    Ctx);
    114   return MCOperand::CreateExpr(Expr);
    115 }
    116 
    117 void MBlazeMCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const {
    118   OutMI.setOpcode(MI->getOpcode());
    119 
    120   for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
    121     const MachineOperand &MO = MI->getOperand(i);
    122 
    123     MCOperand MCOp;
    124     switch (MO.getType()) {
    125     default: llvm_unreachable("unknown operand type");
    126     case MachineOperand::MO_Register:
    127       // Ignore all implicit register operands.
    128       if (MO.isImplicit()) continue;
    129       MCOp = MCOperand::CreateReg(MO.getReg());
    130       break;
    131     case MachineOperand::MO_Immediate:
    132       MCOp = MCOperand::CreateImm(MO.getImm());
    133       break;
    134     case MachineOperand::MO_MachineBasicBlock:
    135       MCOp = MCOperand::CreateExpr(MCSymbolRefExpr::Create(
    136                          MO.getMBB()->getSymbol(), Ctx));
    137       break;
    138     case MachineOperand::MO_GlobalAddress:
    139       MCOp = LowerSymbolOperand(MO, GetGlobalAddressSymbol(MO));
    140       break;
    141     case MachineOperand::MO_ExternalSymbol:
    142       MCOp = LowerSymbolOperand(MO, GetExternalSymbolSymbol(MO));
    143       break;
    144     case MachineOperand::MO_JumpTableIndex:
    145       MCOp = LowerSymbolOperand(MO, GetJumpTableSymbol(MO));
    146       break;
    147     case MachineOperand::MO_ConstantPoolIndex:
    148       MCOp = LowerSymbolOperand(MO, GetConstantPoolIndexSymbol(MO));
    149       break;
    150     case MachineOperand::MO_BlockAddress:
    151       MCOp = LowerSymbolOperand(MO, GetBlockAddressSymbol(MO));
    152       break;
    153     case MachineOperand::MO_FPImmediate:
    154       bool ignored;
    155       APFloat FVal = MO.getFPImm()->getValueAPF();
    156       FVal.convert(APFloat::IEEEsingle, APFloat::rmTowardZero, &ignored);
    157 
    158       APInt IVal = FVal.bitcastToAPInt();
    159       uint64_t Val = *IVal.getRawData();
    160       MCOp = MCOperand::CreateImm(Val);
    161       break;
    162     }
    163 
    164     OutMI.addOperand(MCOp);
    165   }
    166 }
    167