contrib/llvm/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp

   1 //===-- X86ELFObjectWriter.cpp - X86 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/X86FixupKinds.h"
  11 #include "MCTargetDesc/X86MCTargetDesc.h"
  12 #include "llvm/MC/MCELFObjectWriter.h"
  13 #include "llvm/MC/MCExpr.h"
  14 #include "llvm/MC/MCValue.h"
  15 #include "llvm/Support/ELF.h"
  16 #include "llvm/Support/ErrorHandling.h"
  17
  18 using namespace llvm;
  19
  20 namespace {
  21   class X86ELFObjectWriter : public MCELFObjectTargetWriter {
  22   public:
  23     X86ELFObjectWriter(bool IsELF64, uint8_t OSABI, uint16_t EMachine);
  24
  25     virtual ~X86ELFObjectWriter();
  26   protected:
  27     virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
  28                                   bool IsPCRel, bool IsRelocWithSymbol,
  29                                   int64_t Addend) const;
  30   };
  31 }
  32
  33 X86ELFObjectWriter::X86ELFObjectWriter(bool IsELF64, uint8_t OSABI,
  34                                        uint16_t EMachine)
  35   : MCELFObjectTargetWriter(IsELF64, OSABI, EMachine,
  36                             // Only i386 uses Rel instead of RelA.
  37                             /*HasRelocationAddend*/ EMachine != ELF::EM_386) {}
  38
  39 X86ELFObjectWriter::~X86ELFObjectWriter()
  40 {}
  41
  42 unsigned X86ELFObjectWriter::GetRelocType(const MCValue &Target,
  43                                           const MCFixup &Fixup,
  44                                           bool IsPCRel,
  45                                           bool IsRelocWithSymbol,
  46                                           int64_t Addend) const {
  47   // determine the type of the relocation
  48
  49   MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
  50     MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
  51   unsigned Type;
  52   if (getEMachine() == ELF::EM_X86_64) {
  53     if (IsPCRel) {
  54       switch ((unsigned)Fixup.getKind()) {
  55       default: llvm_unreachable("invalid fixup kind!");
  56
  57       case FK_Data_8: Type = ELF::R_X86_64_PC64; break;
  58       case FK_Data_4: Type = ELF::R_X86_64_PC32; break;
  59       case FK_Data_2: Type = ELF::R_X86_64_PC16; break;
  60
  61       case FK_PCRel_8:
  62         assert(Modifier == MCSymbolRefExpr::VK_None);
  63         Type = ELF::R_X86_64_PC64;
  64         break;
  65       case X86::reloc_signed_4byte:
  66       case X86::reloc_riprel_4byte_movq_load:
  67       case X86::reloc_riprel_4byte:
  68       case FK_PCRel_4:
  69         switch (Modifier) {
  70         default:
  71           llvm_unreachable("Unimplemented");
  72         case MCSymbolRefExpr::VK_None:
  73           Type = ELF::R_X86_64_PC32;
  74           break;
  75         case MCSymbolRefExpr::VK_PLT:
  76           Type = ELF::R_X86_64_PLT32;
  77           break;
  78         case MCSymbolRefExpr::VK_GOTPCREL:
  79           Type = ELF::R_X86_64_GOTPCREL;
  80           break;
  81         case MCSymbolRefExpr::VK_GOTTPOFF:
  82           Type = ELF::R_X86_64_GOTTPOFF;
  83         break;
  84         case MCSymbolRefExpr::VK_TLSGD:
  85           Type = ELF::R_X86_64_TLSGD;
  86           break;
  87         case MCSymbolRefExpr::VK_TLSLD:
  88           Type = ELF::R_X86_64_TLSLD;
  89           break;
  90         }
  91         break;
  92       case FK_PCRel_2:
  93         assert(Modifier == MCSymbolRefExpr::VK_None);
  94         Type = ELF::R_X86_64_PC16;
  95         break;
  96       case FK_PCRel_1:
  97         assert(Modifier == MCSymbolRefExpr::VK_None);
  98         Type = ELF::R_X86_64_PC8;
  99         break;
 100       }
 101     } else {
 102       switch ((unsigned)Fixup.getKind()) {
 103       default: llvm_unreachable("invalid fixup kind!");
 104       case FK_Data_8: Type = ELF::R_X86_64_64; break;
 105       case X86::reloc_signed_4byte:
 106         switch (Modifier) {
 107         default:
 108           llvm_unreachable("Unimplemented");
 109         case MCSymbolRefExpr::VK_None:
 110           Type = ELF::R_X86_64_32S;
 111           break;
 112         case MCSymbolRefExpr::VK_GOT:
 113           Type = ELF::R_X86_64_GOT32;
 114           break;
 115         case MCSymbolRefExpr::VK_GOTPCREL:
 116           Type = ELF::R_X86_64_GOTPCREL;
 117           break;
 118         case MCSymbolRefExpr::VK_TPOFF:
 119           Type = ELF::R_X86_64_TPOFF32;
 120           break;
 121         case MCSymbolRefExpr::VK_DTPOFF:
 122           Type = ELF::R_X86_64_DTPOFF32;
 123           break;
 124         }
 125         break;
 126       case FK_Data_4:
 127         Type = ELF::R_X86_64_32;
 128         break;
 129       case FK_Data_2: Type = ELF::R_X86_64_16; break;
 130       case FK_PCRel_1:
 131       case FK_Data_1: Type = ELF::R_X86_64_8; break;
 132       }
 133     }
 134   } else if (getEMachine() == ELF::EM_386) {
 135     if (IsPCRel) {
 136       switch ((unsigned)Fixup.getKind()) {
 137       default: llvm_unreachable("invalid fixup kind!");
 138
 139       case X86::reloc_global_offset_table:
 140         Type = ELF::R_386_GOTPC;
 141         break;
 142
 143       case X86::reloc_signed_4byte:
 144       case FK_PCRel_4:
 145       case FK_Data_4:
 146         switch (Modifier) {
 147         default:
 148           llvm_unreachable("Unimplemented");
 149         case MCSymbolRefExpr::VK_None:
 150           Type = ELF::R_386_PC32;
 151           break;
 152         case MCSymbolRefExpr::VK_PLT:
 153           Type = ELF::R_386_PLT32;
 154           break;
 155         }
 156         break;
 157       }
 158     } else {
 159       switch ((unsigned)Fixup.getKind()) {
 160       default: llvm_unreachable("invalid fixup kind!");
 161
 162       case X86::reloc_global_offset_table:
 163         Type = ELF::R_386_GOTPC;
 164         break;
 165
 166       // FIXME: Should we avoid selecting reloc_signed_4byte in 32 bit mode
 167       // instead?
 168       case X86::reloc_signed_4byte:
 169       case FK_PCRel_4:
 170       case FK_Data_4:
 171         switch (Modifier) {
 172         default:
 173           llvm_unreachable("Unimplemented");
 174         case MCSymbolRefExpr::VK_None:
 175           Type = ELF::R_386_32;
 176           break;
 177         case MCSymbolRefExpr::VK_GOT:
 178           Type = ELF::R_386_GOT32;
 179           break;
 180         case MCSymbolRefExpr::VK_GOTOFF:
 181           Type = ELF::R_386_GOTOFF;
 182           break;
 183         case MCSymbolRefExpr::VK_TLSGD:
 184           Type = ELF::R_386_TLS_GD;
 185           break;
 186         case MCSymbolRefExpr::VK_TPOFF:
 187           Type = ELF::R_386_TLS_LE_32;
 188           break;
 189         case MCSymbolRefExpr::VK_INDNTPOFF:
 190           Type = ELF::R_386_TLS_IE;
 191           break;
 192         case MCSymbolRefExpr::VK_NTPOFF:
 193           Type = ELF::R_386_TLS_LE;
 194           break;
 195         case MCSymbolRefExpr::VK_GOTNTPOFF:
 196           Type = ELF::R_386_TLS_GOTIE;
 197           break;
 198         case MCSymbolRefExpr::VK_TLSLDM:
 199           Type = ELF::R_386_TLS_LDM;
 200           break;
 201         case MCSymbolRefExpr::VK_DTPOFF:
 202           Type = ELF::R_386_TLS_LDO_32;
 203           break;
 204         case MCSymbolRefExpr::VK_GOTTPOFF:
 205           Type = ELF::R_386_TLS_IE_32;
 206           break;
 207         }
 208         break;
 209       case FK_Data_2: Type = ELF::R_386_16; break;
 210       case FK_PCRel_1:
 211       case FK_Data_1: Type = ELF::R_386_8; break;
 212       }
 213     }
 214   } else
 215     llvm_unreachable("Unsupported ELF machine type.");
 216
 217   return Type;
 218 }
 219
 220 MCObjectWriter *llvm::createX86ELFObjectWriter(raw_ostream &OS,
 221                                                bool IsELF64,
 222                                                uint8_t OSABI,
 223                                                uint16_t EMachine) {
 224   MCELFObjectTargetWriter *MOTW =
 225     new X86ELFObjectWriter(IsELF64, OSABI, EMachine);
 226   return createELFObjectWriter(MOTW, OS,  /*IsLittleEndian=*/true);
 227 }