lib/Target/RISCV/MCTargetDesc/RISCVELFObjectWriter.cpp

   1 //===-- RISCVELFObjectWriter.cpp - RISCV ELF Writer -----------------------===//
   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 #include "MCTargetDesc/RISCVFixupKinds.h"
  10 #include "MCTargetDesc/RISCVMCExpr.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   const MCExpr *Expr = Fixup.getValue();
  52   // Determine the type of the relocation
  53   unsigned Kind = Fixup.getTargetKind();
  54   if (IsPCRel) {
  55     switch (Kind) {
  56     default:
  57       llvm_unreachable("invalid fixup kind!");
  58     case FK_Data_4:
  59     case FK_PCRel_4:
  60       return ELF::R_RISCV_32_PCREL;
  61     case RISCV::fixup_riscv_pcrel_hi20:
  62       return ELF::R_RISCV_PCREL_HI20;
  63     case RISCV::fixup_riscv_pcrel_lo12_i:
  64       return ELF::R_RISCV_PCREL_LO12_I;
  65     case RISCV::fixup_riscv_pcrel_lo12_s:
  66       return ELF::R_RISCV_PCREL_LO12_S;
  67     case RISCV::fixup_riscv_got_hi20:
  68       return ELF::R_RISCV_GOT_HI20;
  69     case RISCV::fixup_riscv_tls_got_hi20:
  70       return ELF::R_RISCV_TLS_GOT_HI20;
  71     case RISCV::fixup_riscv_tls_gd_hi20:
  72       return ELF::R_RISCV_TLS_GD_HI20;
  73     case RISCV::fixup_riscv_jal:
  74       return ELF::R_RISCV_JAL;
  75     case RISCV::fixup_riscv_branch:
  76       return ELF::R_RISCV_BRANCH;
  77     case RISCV::fixup_riscv_rvc_jump:
  78       return ELF::R_RISCV_RVC_JUMP;
  79     case RISCV::fixup_riscv_rvc_branch:
  80       return ELF::R_RISCV_RVC_BRANCH;
  81     case RISCV::fixup_riscv_call:
  82       return ELF::R_RISCV_CALL;
  83     case RISCV::fixup_riscv_call_plt:
  84       return ELF::R_RISCV_CALL_PLT;
  85     }
  86   }
  87
  88   switch (Kind) {
  89   default:
  90     llvm_unreachable("invalid fixup kind!");
  91   case FK_Data_4:
  92     if (Expr->getKind() == MCExpr::Target &&
  93         cast<RISCVMCExpr>(Expr)->getKind() == RISCVMCExpr::VK_RISCV_32_PCREL)
  94       return ELF::R_RISCV_32_PCREL;
  95     return ELF::R_RISCV_32;
  96   case FK_Data_8:
  97     return ELF::R_RISCV_64;
  98   case FK_Data_Add_1:
  99     return ELF::R_RISCV_ADD8;
 100   case FK_Data_Add_2:
 101     return ELF::R_RISCV_ADD16;
 102   case FK_Data_Add_4:
 103     return ELF::R_RISCV_ADD32;
 104   case FK_Data_Add_8:
 105     return ELF::R_RISCV_ADD64;
 106   case FK_Data_Add_6b:
 107     return ELF::R_RISCV_SET6;
 108   case FK_Data_Sub_1:
 109     return ELF::R_RISCV_SUB8;
 110   case FK_Data_Sub_2:
 111     return ELF::R_RISCV_SUB16;
 112   case FK_Data_Sub_4:
 113     return ELF::R_RISCV_SUB32;
 114   case FK_Data_Sub_8:
 115     return ELF::R_RISCV_SUB64;
 116   case FK_Data_Sub_6b:
 117     return ELF::R_RISCV_SUB6;
 118   case RISCV::fixup_riscv_hi20:
 119     return ELF::R_RISCV_HI20;
 120   case RISCV::fixup_riscv_lo12_i:
 121     return ELF::R_RISCV_LO12_I;
 122   case RISCV::fixup_riscv_lo12_s:
 123     return ELF::R_RISCV_LO12_S;
 124   case RISCV::fixup_riscv_tprel_hi20:
 125     return ELF::R_RISCV_TPREL_HI20;
 126   case RISCV::fixup_riscv_tprel_lo12_i:
 127     return ELF::R_RISCV_TPREL_LO12_I;
 128   case RISCV::fixup_riscv_tprel_lo12_s:
 129     return ELF::R_RISCV_TPREL_LO12_S;
 130   case RISCV::fixup_riscv_tprel_add:
 131     return ELF::R_RISCV_TPREL_ADD;
 132   case RISCV::fixup_riscv_relax:
 133     return ELF::R_RISCV_RELAX;
 134   case RISCV::fixup_riscv_align:
 135     return ELF::R_RISCV_ALIGN;
 136   }
 137 }
 138
 139 std::unique_ptr<MCObjectTargetWriter>
 140 llvm::createRISCVELFObjectWriter(uint8_t OSABI, bool Is64Bit) {
 141   return std::make_unique<RISCVELFObjectWriter>(OSABI, Is64Bit);
 142 }