1 //=-- BPFMCInstLower.cpp - Convert BPF 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 BPF MachineInstrs to their corresponding 11 // MCInst records. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "BPFMCInstLower.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/Support/ErrorHandling.h" 24 #include "llvm/Support/raw_ostream.h" 25 using namespace llvm; 26 27 MCSymbol * GetGlobalAddressSymbol(const MachineOperand & MO) const28BPFMCInstLower::GetGlobalAddressSymbol(const MachineOperand &MO) const { 29 return Printer.getSymbol(MO.getGlobal()); 30 } 31 32 MCSymbol * GetExternalSymbolSymbol(const MachineOperand & MO) const33BPFMCInstLower::GetExternalSymbolSymbol(const MachineOperand &MO) const { 34 return Printer.GetExternalSymbolSymbol(MO.getSymbolName()); 35 } 36 LowerSymbolOperand(const MachineOperand & MO,MCSymbol * Sym) const37MCOperand BPFMCInstLower::LowerSymbolOperand(const MachineOperand &MO, 38 MCSymbol *Sym) const { 39 40 const MCExpr *Expr = MCSymbolRefExpr::create(Sym, Ctx); 41 42 if (!MO.isJTI() && MO.getOffset()) 43 llvm_unreachable("unknown symbol op"); 44 45 return MCOperand::createExpr(Expr); 46 } 47 Lower(const MachineInstr * MI,MCInst & OutMI) const48void BPFMCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const { 49 OutMI.setOpcode(MI->getOpcode()); 50 51 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { 52 const MachineOperand &MO = MI->getOperand(i); 53 54 MCOperand MCOp; 55 switch (MO.getType()) { 56 default: 57 MI->print(errs()); 58 llvm_unreachable("unknown operand type"); 59 case MachineOperand::MO_Register: 60 // Ignore all implicit register operands. 61 if (MO.isImplicit()) 62 continue; 63 MCOp = MCOperand::createReg(MO.getReg()); 64 break; 65 case MachineOperand::MO_Immediate: 66 MCOp = MCOperand::createImm(MO.getImm()); 67 break; 68 case MachineOperand::MO_MachineBasicBlock: 69 MCOp = MCOperand::createExpr( 70 MCSymbolRefExpr::create(MO.getMBB()->getSymbol(), Ctx)); 71 break; 72 case MachineOperand::MO_RegisterMask: 73 continue; 74 case MachineOperand::MO_ExternalSymbol: 75 MCOp = LowerSymbolOperand(MO, GetExternalSymbolSymbol(MO)); 76 break; 77 case MachineOperand::MO_GlobalAddress: 78 MCOp = LowerSymbolOperand(MO, GetGlobalAddressSymbol(MO)); 79 break; 80 } 81 82 OutMI.addOperand(MCOp); 83 } 84 } 85