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 "BPFAsmPrinter.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/MC/MCStreamer.h"
24#include "llvm/Support/ErrorHandling.h"
25#include "llvm/Support/raw_ostream.h"
26using namespace llvm;
27
28MCSymbol *
29BPFMCInstLower::GetGlobalAddressSymbol(const MachineOperand &MO) const {
30 return Printer.getSymbol(GV: MO.getGlobal());
31}
32
33MCSymbol *
34BPFMCInstLower::GetExternalSymbolSymbol(const MachineOperand &MO) const {
35 return Printer.GetExternalSymbolSymbol(Sym: MO.getSymbolName());
36}
37
38MCOperand BPFMCInstLower::LowerSymbolOperand(const MachineOperand &MO,
39 MCSymbol *Sym) const {
40
41 const MCExpr *Expr = MCSymbolRefExpr::create(Symbol: Sym, Ctx);
42
43 if (!MO.isJTI() && MO.getOffset())
44 llvm_unreachable("unknown symbol op");
45
46 return MCOperand::createExpr(Val: Expr);
47}
48
49void BPFMCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const {
50 OutMI.setOpcode(MI->getOpcode());
51
52 for (const MachineOperand &MO : MI->operands()) {
53 MCOperand MCOp;
54 switch (MO.getType()) {
55 default:
56 MI->print(OS&: 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(Reg: MO.getReg());
63 break;
64 case MachineOperand::MO_Immediate:
65 MCOp = MCOperand::createImm(Val: MO.getImm());
66 break;
67 case MachineOperand::MO_MachineBasicBlock:
68 MCOp = MCOperand::createExpr(
69 Val: MCSymbolRefExpr::create(Symbol: MO.getMBB()->getSymbol(), Ctx));
70 break;
71 case MachineOperand::MO_RegisterMask:
72 continue;
73 case MachineOperand::MO_ExternalSymbol:
74 MCOp = LowerSymbolOperand(MO, Sym: GetExternalSymbolSymbol(MO));
75 break;
76 case MachineOperand::MO_GlobalAddress:
77 MCOp = LowerSymbolOperand(MO, Sym: GetGlobalAddressSymbol(MO));
78 break;
79 case MachineOperand::MO_ConstantPoolIndex:
80 MCOp = LowerSymbolOperand(MO, Sym: Printer.GetCPISymbol(CPID: MO.getIndex()));
81 break;
82 case MachineOperand::MO_JumpTableIndex:
83 MCOp = LowerSymbolOperand(MO, Sym: Printer.getJTPublicSymbol(JTI: MO.getIndex()));
84 break;
85 }
86
87 OutMI.addOperand(Op: MCOp);
88 }
89}
90