1 //===-- RISCVELFObjectWriter.cpp - RISCV 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/RISCVFixupKinds.h"
11 #include "MCTargetDesc/RISCVMCTargetDesc.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 
17 using namespace llvm;
18 
19 namespace {
20 class RISCVELFObjectWriter : public MCELFObjectTargetWriter {
21 public:
22   RISCVELFObjectWriter(uint8_t OSABI, bool Is64Bit);
23 
24   ~RISCVELFObjectWriter() override;
25 
26   // Return true if the given relocation must be with a symbol rather than
27   // section plus offset.
28   bool needsRelocateWithSymbol(const MCSymbol &Sym,
29                                unsigned Type) const override {
30     // TODO: this is very conservative, update once RISC-V psABI requirements
31     //       are clarified.
32     return true;
33   }
34 
35 protected:
36   unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
37                         const MCFixup &Fixup, bool IsPCRel) const override;
38 };
39 }
40 
41 RISCVELFObjectWriter::RISCVELFObjectWriter(uint8_t OSABI, bool Is64Bit)
42     : MCELFObjectTargetWriter(Is64Bit, OSABI, ELF::EM_RISCV,
43                               /*HasRelocationAddend*/ true) {}
44 
45 RISCVELFObjectWriter::~RISCVELFObjectWriter() {}
46 
47 unsigned RISCVELFObjectWriter::getRelocType(MCContext &Ctx,
48                                             const MCValue &Target,
49                                             const MCFixup &Fixup,
50                                             bool IsPCRel) const {
51   // Determine the type of the relocation
52   switch ((unsigned)Fixup.getKind()) {
53   default:
54     llvm_unreachable("invalid fixup kind!");
55   case FK_Data_4:
56     return ELF::R_RISCV_32;
57   case FK_Data_8:
58     return ELF::R_RISCV_64;
59   case RISCV::fixup_riscv_hi20:
60     return ELF::R_RISCV_HI20;
61   case RISCV::fixup_riscv_lo12_i:
62     return ELF::R_RISCV_LO12_I;
63   case RISCV::fixup_riscv_lo12_s:
64     return ELF::R_RISCV_LO12_S;
65   case RISCV::fixup_riscv_pcrel_hi20:
66     return ELF::R_RISCV_PCREL_HI20;
67   case RISCV::fixup_riscv_pcrel_lo12_i:
68     return ELF::R_RISCV_PCREL_LO12_I;
69   case RISCV::fixup_riscv_pcrel_lo12_s:
70     return ELF::R_RISCV_PCREL_LO12_S;
71   case RISCV::fixup_riscv_jal:
72     return ELF::R_RISCV_JAL;
73   case RISCV::fixup_riscv_branch:
74     return ELF::R_RISCV_BRANCH;
75   case RISCV::fixup_riscv_rvc_jump:
76     return ELF::R_RISCV_RVC_JUMP;
77   case RISCV::fixup_riscv_rvc_branch:
78     return ELF::R_RISCV_RVC_BRANCH;
79   case RISCV::fixup_riscv_call:
80     return ELF::R_RISCV_CALL;
81   }
82 }
83 
84 std::unique_ptr<MCObjectTargetWriter>
85 llvm::createRISCVELFObjectWriter(uint8_t OSABI, bool Is64Bit) {
86   return llvm::make_unique<RISCVELFObjectWriter>(OSABI, Is64Bit);
87 }
88