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 (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { 51 const MachineOperand &MO = MI->getOperand(i); 52 53 MCOperand MCOp; 54 switch (MO.getType()) { 55 default: 56 MI->print(errs()); 57 llvm_unreachable("unknown operand type"); 58 case MachineOperand::MO_Register: 59 // Ignore all implicit register operands. 60 if (MO.isImplicit()) 61 continue; 62 MCOp = MCOperand::createReg(MO.getReg()); 63 break; 64 case MachineOperand::MO_Immediate: 65 MCOp = MCOperand::createImm(MO.getImm()); 66 break; 67 case MachineOperand::MO_MachineBasicBlock: 68 MCOp = MCOperand::createExpr( 69 MCSymbolRefExpr::create(MO.getMBB()->getSymbol(), Ctx)); 70 break; 71 case MachineOperand::MO_RegisterMask: 72 continue; 73 case MachineOperand::MO_ExternalSymbol: 74 MCOp = LowerSymbolOperand(MO, GetExternalSymbolSymbol(MO)); 75 break; 76 case MachineOperand::MO_GlobalAddress: 77 MCOp = LowerSymbolOperand(MO, GetGlobalAddressSymbol(MO)); 78 break; 79 } 80 81 OutMI.addOperand(MCOp); 82 } 83 } 84