lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp

   1 //===-- MipsELFObjectWriter.cpp - Mips 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/MipsBaseInfo.h"
  11 #include "MCTargetDesc/MipsFixupKinds.h"
  12 #include "MCTargetDesc/MipsMCTargetDesc.h"
  13 #include "llvm/MC/MCAssembler.h"
  14 #include "llvm/MC/MCELFObjectWriter.h"
  15 #include "llvm/MC/MCExpr.h"
  16 #include "llvm/MC/MCSection.h"
  17 #include "llvm/MC/MCValue.h"
  18 #include "llvm/Support/ErrorHandling.h"
  19 #include <list>
  20
  21 using namespace llvm;
  22
  23 namespace {
  24   class MipsELFObjectWriter : public MCELFObjectTargetWriter {
  25   public:
  26     MipsELFObjectWriter(bool _is64Bit, uint8_t OSABI,
  27                         bool _isN64, bool IsLittleEndian);
  28
  29     virtual ~MipsELFObjectWriter();
  30
  31     unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
  32                           bool IsPCRel) const override;
  33     bool needsRelocateWithSymbol(unsigned Type) const override;
  34   };
  35 }
  36
  37 MipsELFObjectWriter::MipsELFObjectWriter(bool _is64Bit, uint8_t OSABI,
  38                                          bool _isN64, bool IsLittleEndian)
  39   : MCELFObjectTargetWriter(_is64Bit, OSABI, ELF::EM_MIPS,
  40                             /*HasRelocationAddend*/ (_isN64) ? true : false,
  41                             /*IsN64*/ _isN64) {}
  42
  43 MipsELFObjectWriter::~MipsELFObjectWriter() {}
  44
  45 unsigned MipsELFObjectWriter::GetRelocType(const MCValue &Target,
  46                                            const MCFixup &Fixup,
  47                                            bool IsPCRel) const {
  48   // determine the type of the relocation
  49   unsigned Type = (unsigned)ELF::R_MIPS_NONE;
  50   unsigned Kind = (unsigned)Fixup.getKind();
  51
  52   switch (Kind) {
  53   default:
  54     llvm_unreachable("invalid fixup kind!");
  55   case FK_Data_4:
  56     Type = ELF::R_MIPS_32;
  57     break;
  58   case FK_Data_8:
  59     Type = ELF::R_MIPS_64;
  60     break;
  61   case FK_GPRel_4:
  62     if (isN64()) {
  63       Type = setRType((unsigned)ELF::R_MIPS_GPREL32, Type);
  64       Type = setRType2((unsigned)ELF::R_MIPS_64, Type);
  65       Type = setRType3((unsigned)ELF::R_MIPS_NONE, Type);
  66     }
  67     else
  68       Type = ELF::R_MIPS_GPREL32;
  69     break;
  70   case Mips::fixup_Mips_GPREL16:
  71     Type = ELF::R_MIPS_GPREL16;
  72     break;
  73   case Mips::fixup_Mips_26:
  74     Type = ELF::R_MIPS_26;
  75     break;
  76   case Mips::fixup_Mips_CALL16:
  77     Type = ELF::R_MIPS_CALL16;
  78     break;
  79   case Mips::fixup_Mips_GOT_Global:
  80   case Mips::fixup_Mips_GOT_Local:
  81     Type = ELF::R_MIPS_GOT16;
  82     break;
  83   case Mips::fixup_Mips_HI16:
  84     Type = ELF::R_MIPS_HI16;
  85     break;
  86   case Mips::fixup_Mips_LO16:
  87     Type = ELF::R_MIPS_LO16;
  88     break;
  89   case Mips::fixup_Mips_TLSGD:
  90     Type = ELF::R_MIPS_TLS_GD;
  91     break;
  92   case Mips::fixup_Mips_GOTTPREL:
  93     Type = ELF::R_MIPS_TLS_GOTTPREL;
  94     break;
  95   case Mips::fixup_Mips_TPREL_HI:
  96     Type = ELF::R_MIPS_TLS_TPREL_HI16;
  97     break;
  98   case Mips::fixup_Mips_TPREL_LO:
  99     Type = ELF::R_MIPS_TLS_TPREL_LO16;
 100     break;
 101   case Mips::fixup_Mips_TLSLDM:
 102     Type = ELF::R_MIPS_TLS_LDM;
 103     break;
 104   case Mips::fixup_Mips_DTPREL_HI:
 105     Type = ELF::R_MIPS_TLS_DTPREL_HI16;
 106     break;
 107   case Mips::fixup_Mips_DTPREL_LO:
 108     Type = ELF::R_MIPS_TLS_DTPREL_LO16;
 109     break;
 110   case Mips::fixup_Mips_Branch_PCRel:
 111   case Mips::fixup_Mips_PC16:
 112     Type = ELF::R_MIPS_PC16;
 113     break;
 114   case Mips::fixup_Mips_GOT_PAGE:
 115     Type = ELF::R_MIPS_GOT_PAGE;
 116     break;
 117   case Mips::fixup_Mips_GOT_OFST:
 118     Type = ELF::R_MIPS_GOT_OFST;
 119     break;
 120   case Mips::fixup_Mips_GOT_DISP:
 121     Type = ELF::R_MIPS_GOT_DISP;
 122     break;
 123   case Mips::fixup_Mips_GPOFF_HI:
 124     Type = setRType((unsigned)ELF::R_MIPS_GPREL16, Type);
 125     Type = setRType2((unsigned)ELF::R_MIPS_SUB, Type);
 126     Type = setRType3((unsigned)ELF::R_MIPS_HI16, Type);
 127     break;
 128   case Mips::fixup_Mips_GPOFF_LO:
 129     Type = setRType((unsigned)ELF::R_MIPS_GPREL16, Type);
 130     Type = setRType2((unsigned)ELF::R_MIPS_SUB, Type);
 131     Type = setRType3((unsigned)ELF::R_MIPS_LO16, Type);
 132     break;
 133   case Mips::fixup_Mips_HIGHER:
 134     Type = ELF::R_MIPS_HIGHER;
 135     break;
 136   case Mips::fixup_Mips_HIGHEST:
 137     Type = ELF::R_MIPS_HIGHEST;
 138     break;
 139   case Mips::fixup_Mips_GOT_HI16:
 140     Type = ELF::R_MIPS_GOT_HI16;
 141     break;
 142   case Mips::fixup_Mips_GOT_LO16:
 143     Type = ELF::R_MIPS_GOT_LO16;
 144     break;
 145   case Mips::fixup_Mips_CALL_HI16:
 146     Type = ELF::R_MIPS_CALL_HI16;
 147     break;
 148   case Mips::fixup_Mips_CALL_LO16:
 149     Type = ELF::R_MIPS_CALL_LO16;
 150     break;
 151   case Mips::fixup_MICROMIPS_26_S1:
 152     Type = ELF::R_MICROMIPS_26_S1;
 153     break;
 154   case Mips::fixup_MICROMIPS_HI16:
 155     Type = ELF::R_MICROMIPS_HI16;
 156     break;
 157   case Mips::fixup_MICROMIPS_LO16:
 158     Type = ELF::R_MICROMIPS_LO16;
 159     break;
 160   case Mips::fixup_MICROMIPS_GOT16:
 161     Type = ELF::R_MICROMIPS_GOT16;
 162     break;
 163   case Mips::fixup_MICROMIPS_PC16_S1:
 164     Type = ELF::R_MICROMIPS_PC16_S1;
 165     break;
 166   case Mips::fixup_MICROMIPS_CALL16:
 167     Type = ELF::R_MICROMIPS_CALL16;
 168     break;
 169   case Mips::fixup_MICROMIPS_GOT_DISP:
 170     Type = ELF::R_MICROMIPS_GOT_DISP;
 171     break;
 172   case Mips::fixup_MICROMIPS_GOT_PAGE:
 173     Type = ELF::R_MICROMIPS_GOT_PAGE;
 174     break;
 175   case Mips::fixup_MICROMIPS_GOT_OFST:
 176     Type = ELF::R_MICROMIPS_GOT_OFST;
 177     break;
 178   case Mips::fixup_MICROMIPS_TLS_GD:
 179     Type = ELF::R_MICROMIPS_TLS_GD;
 180     break;
 181   case Mips::fixup_MICROMIPS_TLS_LDM:
 182     Type = ELF::R_MICROMIPS_TLS_LDM;
 183     break;
 184   case Mips::fixup_MICROMIPS_TLS_DTPREL_HI16:
 185     Type = ELF::R_MICROMIPS_TLS_DTPREL_HI16;
 186     break;
 187   case Mips::fixup_MICROMIPS_TLS_DTPREL_LO16:
 188     Type = ELF::R_MICROMIPS_TLS_DTPREL_LO16;
 189     break;
 190   case Mips::fixup_MICROMIPS_TLS_TPREL_HI16:
 191     Type = ELF::R_MICROMIPS_TLS_TPREL_HI16;
 192     break;
 193   case Mips::fixup_MICROMIPS_TLS_TPREL_LO16:
 194     Type = ELF::R_MICROMIPS_TLS_TPREL_LO16;
 195     break;
 196   }
 197   return Type;
 198 }
 199
 200 bool
 201 MipsELFObjectWriter::needsRelocateWithSymbol(unsigned Type) const {
 202   // FIXME: This is extremelly conservative. This really needs to use a
 203   // whitelist with a clear explanation for why each realocation needs to
 204   // point to the symbol, not to the section.
 205   switch (Type) {
 206   default:
 207     return true;
 208
 209   case ELF::R_MIPS_26:
 210   case ELF::R_MIPS_LO16:
 211   case ELF::R_MIPS_HI16:
 212   case ELF::R_MIPS_32:
 213   case ELF::R_MIPS_64:
 214   case ELF::R_MIPS_GPREL16:
 215     return false;
 216   }
 217 }
 218
 219 MCObjectWriter *llvm::createMipsELFObjectWriter(raw_ostream &OS,
 220                                                 uint8_t OSABI,
 221                                                 bool IsLittleEndian,
 222                                                 bool Is64Bit) {
 223   MCELFObjectTargetWriter *MOTW = new MipsELFObjectWriter(Is64Bit, OSABI,
 224                                                 (Is64Bit) ? true : false,
 225                                                 IsLittleEndian);
 226   return createELFObjectWriter(MOTW, OS, IsLittleEndian);
 227 }