1 //=-- BPFMCInstLower.cpp - Convert BPF MachineInstr to an 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 // This file contains code to lower BPF MachineInstrs to their corresponding 10 // MCInst records. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "BPFMCInstLower.h" 15 #include "llvm/CodeGen/AsmPrinter.h" 16 #include "llvm/CodeGen/MachineBasicBlock.h" 17 #include "llvm/CodeGen/MachineInstr.h" 18 #include "llvm/MC/MCAsmInfo.h" 19 #include "llvm/MC/MCContext.h" 20 #include "llvm/MC/MCExpr.h" 21 #include "llvm/MC/MCInst.h" 22 #include "llvm/Support/ErrorHandling.h" 23 #include "llvm/Support/raw_ostream.h" 24 using namespace llvm; 25 26 MCSymbol * 27 BPFMCInstLower::GetGlobalAddressSymbol(const MachineOperand &MO) const { 28 return Printer.getSymbol(MO.getGlobal()); 29 } 30 31 MCSymbol * 32 BPFMCInstLower::GetExternalSymbolSymbol(const MachineOperand &MO) const { 33 return Printer.GetExternalSymbolSymbol(MO.getSymbolName()); 34 } 35 36 MCOperand BPFMCInstLower::LowerSymbolOperand(const MachineOperand &MO, 37 MCSymbol *Sym) const { 38 39 const MCExpr *Expr = MCSymbolRefExpr::create(Sym, Ctx); 40 41 if (!MO.isJTI() && MO.getOffset()) 42 llvm_unreachable("unknown symbol op"); 43 44 return MCOperand::createExpr(Expr); 45 } 46 47 void BPFMCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const { 48 OutMI.setOpcode(MI->getOpcode()); 49 50 for (const MachineOperand &MO : MI->operands()) { 51 MCOperand MCOp; 52 switch (MO.getType()) { 53 default: 54 MI->print(errs()); 55 llvm_unreachable("unknown operand type"); 56 case MachineOperand::MO_Register: 57 // Ignore all implicit register operands. 58 if (MO.isImplicit()) 59 continue; 60 MCOp = MCOperand::createReg(MO.getReg()); 61 break; 62 case MachineOperand::MO_Immediate: 63 MCOp = MCOperand::createImm(MO.getImm()); 64 break; 65 case MachineOperand::MO_MachineBasicBlock: 66 MCOp = MCOperand::createExpr( 67 MCSymbolRefExpr::create(MO.getMBB()->getSymbol(), Ctx)); 68 break; 69 case MachineOperand::MO_RegisterMask: 70 continue; 71 case MachineOperand::MO_ExternalSymbol: 72 MCOp = LowerSymbolOperand(MO, GetExternalSymbolSymbol(MO)); 73 break; 74 case MachineOperand::MO_GlobalAddress: 75 MCOp = LowerSymbolOperand(MO, GetGlobalAddressSymbol(MO)); 76 break; 77 } 78 79 OutMI.addOperand(MCOp); 80 } 81 } 82