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"
24using namespace llvm;
25
26MCSymbol *
27BPFMCInstLower::GetGlobalAddressSymbol(const MachineOperand &MO) const {
28 return Printer.getSymbol(GV: MO.getGlobal());
29}
30
31MCSymbol *
32BPFMCInstLower::GetExternalSymbolSymbol(const MachineOperand &MO) const {
33 return Printer.GetExternalSymbolSymbol(Sym: MO.getSymbolName());
34}
35
36MCOperand BPFMCInstLower::LowerSymbolOperand(const MachineOperand &MO,
37 MCSymbol *Sym) const {
38
39 const MCExpr *Expr = MCSymbolRefExpr::create(Symbol: Sym, Ctx);
40
41 if (!MO.isJTI() && MO.getOffset())
42 llvm_unreachable("unknown symbol op");
43
44 return MCOperand::createExpr(Val: Expr);
45}
46
47void 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(OS&: 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(Reg: MO.getReg());
61 break;
62 case MachineOperand::MO_Immediate:
63 MCOp = MCOperand::createImm(Val: MO.getImm());
64 break;
65 case MachineOperand::MO_MachineBasicBlock:
66 MCOp = MCOperand::createExpr(
67 Val: MCSymbolRefExpr::create(Symbol: MO.getMBB()->getSymbol(), Ctx));
68 break;
69 case MachineOperand::MO_RegisterMask:
70 continue;
71 case MachineOperand::MO_ExternalSymbol:
72 MCOp = LowerSymbolOperand(MO, Sym: GetExternalSymbolSymbol(MO));
73 break;
74 case MachineOperand::MO_GlobalAddress:
75 MCOp = LowerSymbolOperand(MO, Sym: GetGlobalAddressSymbol(MO));
76 break;
77 case MachineOperand::MO_ConstantPoolIndex:
78 MCOp = LowerSymbolOperand(MO, Sym: Printer.GetCPISymbol(CPID: MO.getIndex()));
79 break;
80 }
81
82 OutMI.addOperand(Op: MCOp);
83 }
84}
85