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     unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
  28                           bool IsPCRel) const override;
  29   };
  30 }
  31
  32 X86ELFObjectWriter::X86ELFObjectWriter(bool IsELF64, uint8_t OSABI,
  33                                        uint16_t EMachine)
  34   : MCELFObjectTargetWriter(IsELF64, OSABI, EMachine,
  35                             // Only i386 uses Rel instead of RelA.
  36                             /*HasRelocationAddend*/ EMachine != ELF::EM_386) {}
  37
  38 X86ELFObjectWriter::~X86ELFObjectWriter()
  39 {}
  40
  41 unsigned X86ELFObjectWriter::GetRelocType(const MCValue &Target,
  42                                           const MCFixup &Fixup,
  43                                           bool IsPCRel) const {
  44   // determine the type of the relocation
  45
  46   MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant();
  47   if (getEMachine() == ELF::EM_X86_64) {
  48     if (IsPCRel) {
  49       switch ((unsigned)Fixup.getKind()) {
  50       default:
  51         llvm_unreachable("invalid fixup kind!");
  52
  53       case FK_Data_8:
  54         return ELF::R_X86_64_PC64;
  55       case FK_Data_4:
  56         return ELF::R_X86_64_PC32;
  57       case FK_Data_2:
  58         return ELF::R_X86_64_PC16;
  59       case FK_Data_1:
  60         return ELF::R_X86_64_PC8;
  61       case FK_PCRel_8:
  62         assert(Modifier == MCSymbolRefExpr::VK_None);
  63         return ELF::R_X86_64_PC64;
  64       case X86::reloc_signed_4byte:
  65       case X86::reloc_riprel_4byte_movq_load:
  66       case X86::reloc_riprel_4byte:
  67       case FK_PCRel_4:
  68         switch (Modifier) {
  69         default:
  70           llvm_unreachable("Unimplemented");
  71         case MCSymbolRefExpr::VK_None:
  72           return ELF::R_X86_64_PC32;
  73         case MCSymbolRefExpr::VK_PLT:
  74           return ELF::R_X86_64_PLT32;
  75         case MCSymbolRefExpr::VK_GOTPCREL:
  76           return ELF::R_X86_64_GOTPCREL;
  77         case MCSymbolRefExpr::VK_GOTTPOFF:
  78           return ELF::R_X86_64_GOTTPOFF;
  79         case MCSymbolRefExpr::VK_TLSGD:
  80           return ELF::R_X86_64_TLSGD;
  81         case MCSymbolRefExpr::VK_TLSLD:
  82           return ELF::R_X86_64_TLSLD;
  83         }
  84         break;
  85       case FK_PCRel_2:
  86         assert(Modifier == MCSymbolRefExpr::VK_None);
  87         return ELF::R_X86_64_PC16;
  88       case FK_PCRel_1:
  89         assert(Modifier == MCSymbolRefExpr::VK_None);
  90         return ELF::R_X86_64_PC8;
  91       }
  92     } else {
  93       switch ((unsigned)Fixup.getKind()) {
  94       default:
  95         llvm_unreachable("invalid fixup kind!");
  96       case X86::reloc_global_offset_table8:
  97         return ELF::R_X86_64_GOTPC64;
  98       case X86::reloc_global_offset_table:
  99         return ELF::R_X86_64_GOTPC32;
 100       case FK_Data_8:
 101         switch (Modifier) {
 102         default:
 103           llvm_unreachable("Unimplemented");
 104         case MCSymbolRefExpr::VK_None:
 105           return ELF::R_X86_64_64;
 106         case MCSymbolRefExpr::VK_GOT:
 107           return ELF::R_X86_64_GOT64;
 108         case MCSymbolRefExpr::VK_GOTOFF:
 109           return ELF::R_X86_64_GOTOFF64;
 110         case MCSymbolRefExpr::VK_TPOFF:
 111           return ELF::R_X86_64_TPOFF64;
 112         case MCSymbolRefExpr::VK_DTPOFF:
 113           return ELF::R_X86_64_DTPOFF64;
 114         case MCSymbolRefExpr::VK_SIZE:
 115           return ELF::R_X86_64_SIZE64;
 116         }
 117         break;
 118       case X86::reloc_signed_4byte:
 119         switch (Modifier) {
 120         default:
 121           llvm_unreachable("Unimplemented");
 122         case MCSymbolRefExpr::VK_None:
 123           return ELF::R_X86_64_32S;
 124         case MCSymbolRefExpr::VK_GOT:
 125           return ELF::R_X86_64_GOT32;
 126         case MCSymbolRefExpr::VK_GOTPCREL:
 127           return ELF::R_X86_64_GOTPCREL;
 128         case MCSymbolRefExpr::VK_TPOFF:
 129           return ELF::R_X86_64_TPOFF32;
 130         case MCSymbolRefExpr::VK_DTPOFF:
 131           return ELF::R_X86_64_DTPOFF32;
 132         case MCSymbolRefExpr::VK_SIZE:
 133           return ELF::R_X86_64_SIZE32;
 134         }
 135         break;
 136       case FK_Data_4:
 137         return ELF::R_X86_64_32;
 138       case FK_Data_2:
 139         return ELF::R_X86_64_16;
 140       case FK_PCRel_1:
 141       case FK_Data_1:
 142         return ELF::R_X86_64_8;
 143       }
 144     }
 145   } else {
 146     assert(getEMachine() == ELF::EM_386 && "Unsupported ELF machine type.");
 147     if (IsPCRel) {
 148       switch ((unsigned)Fixup.getKind()) {
 149       default:
 150         llvm_unreachable("invalid fixup kind!");
 151
 152       case X86::reloc_global_offset_table:
 153         return ELF::R_386_GOTPC;
 154       case FK_PCRel_1:
 155       case FK_Data_1:
 156         switch (Modifier) {
 157         default:
 158           llvm_unreachable("Unimplemented");
 159         case MCSymbolRefExpr::VK_None:
 160           return ELF::R_386_PC8;
 161         }
 162         break;
 163
 164       case FK_PCRel_2:
 165       case FK_Data_2:
 166         switch (Modifier) {
 167         default:
 168           llvm_unreachable("Unimplemented");
 169         case MCSymbolRefExpr::VK_None:
 170           return ELF::R_386_PC16;
 171         }
 172         break;
 173
 174       case X86::reloc_riprel_4byte:
 175       case X86::reloc_signed_4byte:
 176       case FK_PCRel_4:
 177       case FK_Data_4:
 178         switch (Modifier) {
 179         default:
 180           llvm_unreachable("Unimplemented");
 181         case MCSymbolRefExpr::VK_None:
 182           return ELF::R_386_PC32;
 183         case MCSymbolRefExpr::VK_PLT:
 184           return ELF::R_386_PLT32;
 185         }
 186         break;
 187       }
 188     } else {
 189       switch ((unsigned)Fixup.getKind()) {
 190       default:
 191         llvm_unreachable("invalid fixup kind!");
 192
 193       case X86::reloc_global_offset_table:
 194         return ELF::R_386_GOTPC;
 195         break;
 196
 197       // FIXME: Should we avoid selecting reloc_signed_4byte in 32 bit mode
 198       // instead?
 199       case X86::reloc_signed_4byte:
 200       case FK_PCRel_4:
 201       case FK_Data_4:
 202         switch (Modifier) {
 203         default:
 204           llvm_unreachable("Unimplemented");
 205         case MCSymbolRefExpr::VK_None:
 206           return  ELF::R_386_32;
 207         case MCSymbolRefExpr::VK_GOT:
 208           return ELF::R_386_GOT32;
 209         case MCSymbolRefExpr::VK_PLT:
 210           return ELF::R_386_PLT32;
 211         case MCSymbolRefExpr::VK_GOTOFF:
 212           return ELF::R_386_GOTOFF;
 213         case MCSymbolRefExpr::VK_TLSGD:
 214           return ELF::R_386_TLS_GD;
 215         case MCSymbolRefExpr::VK_TPOFF:
 216           return ELF::R_386_TLS_LE_32;
 217         case MCSymbolRefExpr::VK_INDNTPOFF:
 218           return ELF::R_386_TLS_IE;
 219         case MCSymbolRefExpr::VK_NTPOFF:
 220           return ELF::R_386_TLS_LE;
 221         case MCSymbolRefExpr::VK_GOTNTPOFF:
 222           return  ELF::R_386_TLS_GOTIE;
 223         case MCSymbolRefExpr::VK_TLSLDM:
 224           return ELF::R_386_TLS_LDM;
 225         case MCSymbolRefExpr::VK_DTPOFF:
 226           return ELF::R_386_TLS_LDO_32;
 227         case MCSymbolRefExpr::VK_GOTTPOFF:
 228           return ELF::R_386_TLS_IE_32;
 229         }
 230         break;
 231       case FK_Data_2:
 232         return ELF::R_386_16;
 233       case FK_PCRel_1:
 234       case FK_Data_1:
 235         return ELF::R_386_8;
 236       }
 237     }
 238   }
 239 }
 240
 241 MCObjectWriter *llvm::createX86ELFObjectWriter(raw_ostream &OS,
 242                                                bool IsELF64,
 243                                                uint8_t OSABI,
 244                                                uint16_t EMachine) {
 245   MCELFObjectTargetWriter *MOTW =
 246     new X86ELFObjectWriter(IsELF64, OSABI, EMachine);
 247   return createELFObjectWriter(MOTW, OS,  /*IsLittleEndian=*/true);
 248 }