lib/Target/XCore/XCoreMCInstLower.cpp

   1 //===-- XCoreMCInstLower.cpp - Convert XCore MachineInstr to MCInst -------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 ///
   9 /// \file
  10 /// This file contains code to lower XCore MachineInstrs to their
  11 /// corresponding MCInst records.
  12 ///
  13 //===----------------------------------------------------------------------===//
  14 #include "XCoreMCInstLower.h"
  15 #include "llvm/CodeGen/AsmPrinter.h"
  16 #include "llvm/CodeGen/MachineFunction.h"
  17 #include "llvm/CodeGen/MachineInstr.h"
  18 #include "llvm/CodeGen/MachineOperand.h"
  19 #include "llvm/IR/Mangler.h"
  20 #include "llvm/MC/MCContext.h"
  21 #include "llvm/MC/MCExpr.h"
  22 #include "llvm/MC/MCInst.h"
  23
  24 using namespace llvm;
  25
  26 XCoreMCInstLower::XCoreMCInstLower(class AsmPrinter &asmprinter)
  27     : Printer(asmprinter) {}
  28
  29 void XCoreMCInstLower::Initialize(MCContext *C) { Ctx = C; }
  30
  31 MCOperand XCoreMCInstLower::LowerSymbolOperand(const MachineOperand &MO,
  32                                                MachineOperandType MOTy,
  33                                                unsigned Offset) const {
  34   MCSymbolRefExpr::VariantKind Kind = MCSymbolRefExpr::VK_None;
  35   const MCSymbol *Symbol;
  36
  37   switch (MOTy) {
  38     case MachineOperand::MO_MachineBasicBlock:
  39       Symbol = MO.getMBB()->getSymbol();
  40       break;
  41     case MachineOperand::MO_GlobalAddress:
  42       Symbol = Printer.getSymbol(MO.getGlobal());
  43       Offset += MO.getOffset();
  44       break;
  45     case MachineOperand::MO_BlockAddress:
  46       Symbol = Printer.GetBlockAddressSymbol(MO.getBlockAddress());
  47       Offset += MO.getOffset();
  48       break;
  49     case MachineOperand::MO_ExternalSymbol:
  50       Symbol = Printer.GetExternalSymbolSymbol(MO.getSymbolName());
  51       Offset += MO.getOffset();
  52       break;
  53     case MachineOperand::MO_JumpTableIndex:
  54       Symbol = Printer.GetJTISymbol(MO.getIndex());
  55       break;
  56     case MachineOperand::MO_ConstantPoolIndex:
  57       Symbol = Printer.GetCPISymbol(MO.getIndex());
  58       Offset += MO.getOffset();
  59       break;
  60     default:
  61       llvm_unreachable("<unknown operand type>");
  62   }
  63
  64   const MCSymbolRefExpr *MCSym = MCSymbolRefExpr::create(Symbol, Kind, *Ctx);
  65
  66   if (!Offset)
  67     return MCOperand::createExpr(MCSym);
  68
  69   // Assume offset is never negative.
  70   assert(Offset > 0);
  71
  72   const MCConstantExpr *OffsetExpr =  MCConstantExpr::create(Offset, *Ctx);
  73   const MCBinaryExpr *Add = MCBinaryExpr::createAdd(MCSym, OffsetExpr, *Ctx);
  74   return MCOperand::createExpr(Add);
  75 }
  76
  77 MCOperand XCoreMCInstLower::LowerOperand(const MachineOperand &MO,
  78                                          unsigned offset) const {
  79   MachineOperandType MOTy = MO.getType();
  80
  81   switch (MOTy) {
  82     default: llvm_unreachable("unknown operand type");
  83     case MachineOperand::MO_Register:
  84       // Ignore all implicit register operands.
  85       if (MO.isImplicit()) break;
  86       return MCOperand::createReg(MO.getReg());
  87     case MachineOperand::MO_Immediate:
  88       return MCOperand::createImm(MO.getImm() + offset);
  89     case MachineOperand::MO_MachineBasicBlock:
  90     case MachineOperand::MO_GlobalAddress:
  91     case MachineOperand::MO_ExternalSymbol:
  92     case MachineOperand::MO_JumpTableIndex:
  93     case MachineOperand::MO_ConstantPoolIndex:
  94     case MachineOperand::MO_BlockAddress:
  95       return LowerSymbolOperand(MO, MOTy, offset);
  96     case MachineOperand::MO_RegisterMask:
  97       break;
  98   }
  99
 100   return MCOperand();
 101 }
 102
 103 void XCoreMCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const {
 104   OutMI.setOpcode(MI->getOpcode());
 105
 106   for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
 107     const MachineOperand &MO = MI->getOperand(i);
 108     MCOperand MCOp = LowerOperand(MO);
 109
 110     if (MCOp.isValid())
 111       OutMI.addOperand(MCOp);
 112   }
 113 }