1 //===-- BPFELFObjectWriter.cpp - BPF ELF Writer ---------------------------===//
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 #include "MCTargetDesc/BPFMCTargetDesc.h"
11 #include "llvm/BinaryFormat/ELF.h"
12 #include "llvm/MC/MCELFObjectWriter.h"
13 #include "llvm/MC/MCFixup.h"
14 #include "llvm/MC/MCObjectWriter.h"
15 #include "llvm/Support/ErrorHandling.h"
16 #include <cstdint>
17
18 using namespace llvm;
19
20 namespace {
21
22 class BPFELFObjectWriter : public MCELFObjectTargetWriter {
23 public:
24 BPFELFObjectWriter(uint8_t OSABI);
25 ~BPFELFObjectWriter() override = default;
26
27 protected:
28 unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
29 const MCFixup &Fixup, bool IsPCRel) const override;
30 };
31
32 } // end anonymous namespace
33
BPFELFObjectWriter(uint8_t OSABI)34 BPFELFObjectWriter::BPFELFObjectWriter(uint8_t OSABI)
35 : MCELFObjectTargetWriter(/*Is64Bit*/ true, OSABI, ELF::EM_BPF,
36 /*HasRelocationAddend*/ false) {}
37
getRelocType(MCContext & Ctx,const MCValue & Target,const MCFixup & Fixup,bool IsPCRel) const38 unsigned BPFELFObjectWriter::getRelocType(MCContext &Ctx, const MCValue &Target,
39 const MCFixup &Fixup,
40 bool IsPCRel) const {
41 // determine the type of the relocation
42 switch ((unsigned)Fixup.getKind()) {
43 default:
44 llvm_unreachable("invalid fixup kind!");
45 case FK_SecRel_8:
46 return ELF::R_BPF_64_64;
47 case FK_PCRel_4:
48 case FK_SecRel_4:
49 return ELF::R_BPF_64_32;
50 case FK_Data_8:
51 return ELF::R_BPF_64_64;
52 case FK_Data_4:
53 return ELF::R_BPF_64_32;
54 }
55 }
56
57 std::unique_ptr<MCObjectTargetWriter>
createBPFELFObjectWriter(uint8_t OSABI)58 llvm::createBPFELFObjectWriter(uint8_t OSABI) {
59 return llvm::make_unique<BPFELFObjectWriter>(OSABI);
60 }
61