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      1 //===-- MSP430MCInstLower.cpp - Convert MSP430 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 MSP430 MachineInstrs to their corresponding
     11 // MCInst records.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #include "MSP430MCInstLower.h"
     16 #include "llvm/CodeGen/AsmPrinter.h"
     17 #include "llvm/CodeGen/MachineBasicBlock.h"
     18 #include "llvm/CodeGen/MachineInstr.h"
     19 #include "llvm/MC/MCAsmInfo.h"
     20 #include "llvm/MC/MCContext.h"
     21 #include "llvm/MC/MCExpr.h"
     22 #include "llvm/MC/MCInst.h"
     23 #include "llvm/Target/Mangler.h"
     24 #include "llvm/Support/raw_ostream.h"
     25 #include "llvm/Support/ErrorHandling.h"
     26 #include "llvm/ADT/SmallString.h"
     27 using namespace llvm;
     28 
     29 MCSymbol *MSP430MCInstLower::
     30 GetGlobalAddressSymbol(const MachineOperand &MO) const {
     31   switch (MO.getTargetFlags()) {
     32   default: llvm_unreachable("Unknown target flag on GV operand");
     33   case 0: break;
     34   }
     35 
     36   return Printer.Mang->getSymbol(MO.getGlobal());
     37 }
     38 
     39 MCSymbol *MSP430MCInstLower::
     40 GetExternalSymbolSymbol(const MachineOperand &MO) const {
     41   switch (MO.getTargetFlags()) {
     42   default: assert(0 && "Unknown target flag on GV operand");
     43   case 0: break;
     44   }
     45 
     46   return Printer.GetExternalSymbolSymbol(MO.getSymbolName());
     47 }
     48 
     49 MCSymbol *MSP430MCInstLower::
     50 GetJumpTableSymbol(const MachineOperand &MO) const {
     51   SmallString<256> Name;
     52   raw_svector_ostream(Name) << Printer.MAI->getPrivateGlobalPrefix() << "JTI"
     53                             << Printer.getFunctionNumber() << '_'
     54                             << MO.getIndex();
     55 
     56   switch (MO.getTargetFlags()) {
     57   default: llvm_unreachable("Unknown target flag on GV operand");
     58   case 0: break;
     59   }
     60 
     61   // Create a symbol for the name.
     62   return Ctx.GetOrCreateSymbol(Name.str());
     63 }
     64 
     65 MCSymbol *MSP430MCInstLower::
     66 GetConstantPoolIndexSymbol(const MachineOperand &MO) const {
     67   SmallString<256> Name;
     68   raw_svector_ostream(Name) << Printer.MAI->getPrivateGlobalPrefix() << "CPI"
     69                             << Printer.getFunctionNumber() << '_'
     70                             << MO.getIndex();
     71 
     72   switch (MO.getTargetFlags()) {
     73   default: llvm_unreachable("Unknown target flag on GV operand");
     74   case 0: break;
     75   }
     76 
     77   // Create a symbol for the name.
     78   return Ctx.GetOrCreateSymbol(Name.str());
     79 }
     80 
     81 MCSymbol *MSP430MCInstLower::
     82 GetBlockAddressSymbol(const MachineOperand &MO) const {
     83   switch (MO.getTargetFlags()) {
     84   default: assert(0 && "Unknown target flag on GV operand");
     85   case 0: break;
     86   }
     87 
     88   return Printer.GetBlockAddressSymbol(MO.getBlockAddress());
     89 }
     90 
     91 MCOperand MSP430MCInstLower::
     92 LowerSymbolOperand(const MachineOperand &MO, MCSymbol *Sym) const {
     93   // FIXME: We would like an efficient form for this, so we don't have to do a
     94   // lot of extra uniquing.
     95   const MCExpr *Expr = MCSymbolRefExpr::Create(Sym, Ctx);
     96 
     97   switch (MO.getTargetFlags()) {
     98   default: llvm_unreachable("Unknown target flag on GV operand");
     99   case 0: break;
    100   }
    101 
    102   if (!MO.isJTI() && MO.getOffset())
    103     Expr = MCBinaryExpr::CreateAdd(Expr,
    104                                    MCConstantExpr::Create(MO.getOffset(), Ctx),
    105                                    Ctx);
    106   return MCOperand::CreateExpr(Expr);
    107 }
    108 
    109 void MSP430MCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const {
    110   OutMI.setOpcode(MI->getOpcode());
    111 
    112   for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
    113     const MachineOperand &MO = MI->getOperand(i);
    114 
    115     MCOperand MCOp;
    116     switch (MO.getType()) {
    117     default:
    118       MI->dump();
    119       assert(0 && "unknown operand type");
    120     case MachineOperand::MO_Register:
    121       // Ignore all implicit register operands.
    122       if (MO.isImplicit()) continue;
    123       MCOp = MCOperand::CreateReg(MO.getReg());
    124       break;
    125     case MachineOperand::MO_Immediate:
    126       MCOp = MCOperand::CreateImm(MO.getImm());
    127       break;
    128     case MachineOperand::MO_MachineBasicBlock:
    129       MCOp = MCOperand::CreateExpr(MCSymbolRefExpr::Create(
    130                          MO.getMBB()->getSymbol(), Ctx));
    131       break;
    132     case MachineOperand::MO_GlobalAddress:
    133       MCOp = LowerSymbolOperand(MO, GetGlobalAddressSymbol(MO));
    134       break;
    135     case MachineOperand::MO_ExternalSymbol:
    136       MCOp = LowerSymbolOperand(MO, GetExternalSymbolSymbol(MO));
    137       break;
    138     case MachineOperand::MO_JumpTableIndex:
    139       MCOp = LowerSymbolOperand(MO, GetJumpTableSymbol(MO));
    140       break;
    141     case MachineOperand::MO_ConstantPoolIndex:
    142       MCOp = LowerSymbolOperand(MO, GetConstantPoolIndexSymbol(MO));
    143       break;
    144     case MachineOperand::MO_BlockAddress:
    145       MCOp = LowerSymbolOperand(MO, GetBlockAddressSymbol(MO));
    146     }
    147 
    148     OutMI.addOperand(MCOp);
    149   }
    150 }
    151