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:
 105         switch (Modifier) {
 106         default:
 107           llvm_unreachable("Unimplemented");
 108         case MCSymbolRefExpr::VK_None:
 109           Type = ELF::R_X86_64_64;
 110           break;
 111         case MCSymbolRefExpr::VK_GOT:
 112           Type = ELF::R_X86_64_GOT64;
 113           break;
 114         case MCSymbolRefExpr::VK_GOTOFF:
 115           Type = ELF::R_X86_64_GOTOFF64;
 116           break;
 117         case MCSymbolRefExpr::VK_TPOFF:
 118           Type = ELF::R_X86_64_TPOFF64;
 119           break;
 120         case MCSymbolRefExpr::VK_DTPOFF:
 121           Type = ELF::R_X86_64_DTPOFF64;
 122           break;
 123         }
 124         break;
 125       case X86::reloc_signed_4byte:
 126         switch (Modifier) {
 127         default:
 128           llvm_unreachable("Unimplemented");
 129         case MCSymbolRefExpr::VK_None:
 130           Type = ELF::R_X86_64_32S;
 131           break;
 132         case MCSymbolRefExpr::VK_GOT:
 133           Type = ELF::R_X86_64_GOT32;
 134           break;
 135         case MCSymbolRefExpr::VK_GOTPCREL:
 136           Type = ELF::R_X86_64_GOTPCREL;
 137           break;
 138         case MCSymbolRefExpr::VK_TPOFF:
 139           Type = ELF::R_X86_64_TPOFF32;
 140           break;
 141         case MCSymbolRefExpr::VK_DTPOFF:
 142           Type = ELF::R_X86_64_DTPOFF32;
 143           break;
 144         }
 145         break;
 146       case FK_Data_4:
 147         Type = ELF::R_X86_64_32;
 148         break;
 149       case FK_Data_2: Type = ELF::R_X86_64_16; break;
 150       case FK_PCRel_1:
 151       case FK_Data_1: Type = ELF::R_X86_64_8; break;
 152       }
 153     }
 154   } else if (getEMachine() == ELF::EM_386) {
 155     if (IsPCRel) {
 156       switch ((unsigned)Fixup.getKind()) {
 157       default: llvm_unreachable("invalid fixup kind!");
 158
 159       case X86::reloc_global_offset_table:
 160         Type = ELF::R_386_GOTPC;
 161         break;
 162
 163       case X86::reloc_signed_4byte:
 164       case FK_PCRel_4:
 165       case FK_Data_4:
 166         switch (Modifier) {
 167         default:
 168           llvm_unreachable("Unimplemented");
 169         case MCSymbolRefExpr::VK_None:
 170           Type = ELF::R_386_PC32;
 171           break;
 172         case MCSymbolRefExpr::VK_PLT:
 173           Type = ELF::R_386_PLT32;
 174           break;
 175         }
 176         break;
 177       }
 178     } else {
 179       switch ((unsigned)Fixup.getKind()) {
 180       default: llvm_unreachable("invalid fixup kind!");
 181
 182       case X86::reloc_global_offset_table:
 183         Type = ELF::R_386_GOTPC;
 184         break;
 185
 186       // FIXME: Should we avoid selecting reloc_signed_4byte in 32 bit mode
 187       // instead?
 188       case X86::reloc_signed_4byte:
 189       case FK_PCRel_4:
 190       case FK_Data_4:
 191         switch (Modifier) {
 192         default:
 193           llvm_unreachable("Unimplemented");
 194         case MCSymbolRefExpr::VK_None:
 195           Type = ELF::R_386_32;
 196           break;
 197         case MCSymbolRefExpr::VK_GOT:
 198           Type = ELF::R_386_GOT32;
 199           break;
 200         case MCSymbolRefExpr::VK_GOTOFF:
 201           Type = ELF::R_386_GOTOFF;
 202           break;
 203         case MCSymbolRefExpr::VK_TLSGD:
 204           Type = ELF::R_386_TLS_GD;
 205           break;
 206         case MCSymbolRefExpr::VK_TPOFF:
 207           Type = ELF::R_386_TLS_LE_32;
 208           break;
 209         case MCSymbolRefExpr::VK_INDNTPOFF:
 210           Type = ELF::R_386_TLS_IE;
 211           break;
 212         case MCSymbolRefExpr::VK_NTPOFF:
 213           Type = ELF::R_386_TLS_LE;
 214           break;
 215         case MCSymbolRefExpr::VK_GOTNTPOFF:
 216           Type = ELF::R_386_TLS_GOTIE;
 217           break;
 218         case MCSymbolRefExpr::VK_TLSLDM:
 219           Type = ELF::R_386_TLS_LDM;
 220           break;
 221         case MCSymbolRefExpr::VK_DTPOFF:
 222           Type = ELF::R_386_TLS_LDO_32;
 223           break;
 224         case MCSymbolRefExpr::VK_GOTTPOFF:
 225           Type = ELF::R_386_TLS_IE_32;
 226           break;
 227         }
 228         break;
 229       case FK_Data_2: Type = ELF::R_386_16; break;
 230       case FK_PCRel_1:
 231       case FK_Data_1: Type = ELF::R_386_8; break;
 232       }
 233     }
 234   } else
 235     llvm_unreachable("Unsupported ELF machine type.");
 236
 237   return Type;
 238 }
 239
 240 MCObjectWriter *llvm::createX86ELFObjectWriter(raw_ostream &OS,
 241                                                bool IsELF64,
 242                                                uint8_t OSABI,
 243                                                uint16_t EMachine) {
 244   MCELFObjectTargetWriter *MOTW =
 245     new X86ELFObjectWriter(IsELF64, OSABI, EMachine);
 246   return createELFObjectWriter(MOTW, OS,  /*IsLittleEndian=*/true);
 247 }