lib/Target/ARM/ARMMCInstLower.cpp

   1 //===-- ARMMCInstLower.cpp - Convert ARM 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 ARM MachineInstrs to their corresponding
  11 // MCInst records.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "ARM.h"
  16 #include "ARMAsmPrinter.h"
  17 #include "ARMMCExpr.h"
  18 #include "llvm/Constants.h"
  19 #include "llvm/CodeGen/MachineBasicBlock.h"
  20 #include "llvm/MC/MCExpr.h"
  21 #include "llvm/MC/MCInst.h"
  22 #include "llvm/Target/Mangler.h"
  23 using namespace llvm;
  24
  25
  26 MCOperand ARMAsmPrinter::GetSymbolRef(const MachineOperand &MO,
  27                                       const MCSymbol *Symbol) {
  28   const MCExpr *Expr;
  29   switch (MO.getTargetFlags()) {
  30   default: {
  31     Expr = MCSymbolRefExpr::Create(Symbol, MCSymbolRefExpr::VK_None,
  32                                    OutContext);
  33     switch (MO.getTargetFlags()) {
  34     default:
  35       assert(0 && "Unknown target flag on symbol operand");
  36     case 0:
  37       break;
  38     case ARMII::MO_LO16:
  39       Expr = MCSymbolRefExpr::Create(Symbol, MCSymbolRefExpr::VK_None,
  40                                      OutContext);
  41       Expr = ARMMCExpr::CreateLower16(Expr, OutContext);
  42       break;
  43     case ARMII::MO_HI16:
  44       Expr = MCSymbolRefExpr::Create(Symbol, MCSymbolRefExpr::VK_None,
  45                                      OutContext);
  46       Expr = ARMMCExpr::CreateUpper16(Expr, OutContext);
  47       break;
  48     }
  49     break;
  50   }
  51
  52   case ARMII::MO_PLT:
  53     Expr = MCSymbolRefExpr::Create(Symbol, MCSymbolRefExpr::VK_ARM_PLT,
  54                                    OutContext);
  55     break;
  56   }
  57
  58   if (!MO.isJTI() && MO.getOffset())
  59     Expr = MCBinaryExpr::CreateAdd(Expr,
  60                                    MCConstantExpr::Create(MO.getOffset(),
  61                                                           OutContext),
  62                                    OutContext);
  63   return MCOperand::CreateExpr(Expr);
  64
  65 }
  66
  67 bool ARMAsmPrinter::lowerOperand(const MachineOperand &MO,
  68                                  MCOperand &MCOp) {
  69   switch (MO.getType()) {
  70   default:
  71     assert(0 && "unknown operand type");
  72     return false;
  73   case MachineOperand::MO_Register:
  74     // Ignore all non-CPSR implicit register operands.
  75     if (MO.isImplicit() && MO.getReg() != ARM::CPSR)
  76       return false;
  77     assert(!MO.getSubReg() && "Subregs should be eliminated!");
  78     MCOp = MCOperand::CreateReg(MO.getReg());
  79     break;
  80   case MachineOperand::MO_Immediate:
  81     MCOp = MCOperand::CreateImm(MO.getImm());
  82     break;
  83   case MachineOperand::MO_MachineBasicBlock:
  84     MCOp = MCOperand::CreateExpr(MCSymbolRefExpr::Create(
  85         MO.getMBB()->getSymbol(), OutContext));
  86     break;
  87   case MachineOperand::MO_GlobalAddress:
  88     MCOp = GetSymbolRef(MO, Mang->getSymbol(MO.getGlobal()));
  89     break;
  90   case MachineOperand::MO_ExternalSymbol:
  91    MCOp = GetSymbolRef(MO,
  92                         GetExternalSymbolSymbol(MO.getSymbolName()));
  93     break;
  94   case MachineOperand::MO_JumpTableIndex:
  95     MCOp = GetSymbolRef(MO, GetJTISymbol(MO.getIndex()));
  96     break;
  97   case MachineOperand::MO_ConstantPoolIndex:
  98     MCOp = GetSymbolRef(MO, GetCPISymbol(MO.getIndex()));
  99     break;
 100   case MachineOperand::MO_BlockAddress:
 101     MCOp = GetSymbolRef(MO, GetBlockAddressSymbol(MO.getBlockAddress()));
 102     break;
 103   case MachineOperand::MO_FPImmediate: {
 104     APFloat Val = MO.getFPImm()->getValueAPF();
 105     bool ignored;
 106     Val.convert(APFloat::IEEEdouble, APFloat::rmTowardZero, &ignored);
 107     MCOp = MCOperand::CreateFPImm(Val.convertToDouble());
 108     break;
 109   }
 110   }
 111   return true;
 112 }
 113
 114 void llvm::LowerARMMachineInstrToMCInst(const MachineInstr *MI, MCInst &OutMI,
 115                                         ARMAsmPrinter &AP) {
 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     if (AP.lowerOperand(MO, MCOp))
 123       OutMI.addOperand(MCOp);
 124   }
 125 }