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 is64Bit, uint8_t OSABI);
  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 Is64Bit, uint8_t OSABI)
  34   : MCELFObjectTargetWriter(Is64Bit, OSABI,
  35                             Is64Bit ?  ELF::EM_X86_64 : ELF::EM_386,
  36                             /*HasRelocationAddend*/ Is64Bit) {}
  37
  38 X86ELFObjectWriter::~X86ELFObjectWriter()
  39 {}
  40
  41 unsigned X86ELFObjectWriter::GetRelocType(const MCValue &Target,
  42                                           const MCFixup &Fixup,
  43                                           bool IsPCRel,
  44                                           bool IsRelocWithSymbol,
  45                                           int64_t Addend) const {
  46   // determine the type of the relocation
  47
  48   MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
  49     MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
  50   unsigned Type;
  51   if (is64Bit()) {
  52     if (IsPCRel) {
  53       switch ((unsigned)Fixup.getKind()) {
  54       default: llvm_unreachable("invalid fixup kind!");
  55
  56       case FK_Data_8: Type = ELF::R_X86_64_PC64; break;
  57       case FK_Data_4: Type = ELF::R_X86_64_PC32; break;
  58       case FK_Data_2: Type = ELF::R_X86_64_PC16; break;
  59
  60       case FK_PCRel_8:
  61         assert(Modifier == MCSymbolRefExpr::VK_None);
  62         Type = ELF::R_X86_64_PC64;
  63         break;
  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           Type = ELF::R_X86_64_PC32;
  73           break;
  74         case MCSymbolRefExpr::VK_PLT:
  75           Type = ELF::R_X86_64_PLT32;
  76           break;
  77         case MCSymbolRefExpr::VK_GOTPCREL:
  78           Type = ELF::R_X86_64_GOTPCREL;
  79           break;
  80         case MCSymbolRefExpr::VK_GOTTPOFF:
  81           Type = ELF::R_X86_64_GOTTPOFF;
  82         break;
  83         case MCSymbolRefExpr::VK_TLSGD:
  84           Type = ELF::R_X86_64_TLSGD;
  85           break;
  86         case MCSymbolRefExpr::VK_TLSLD:
  87           Type = ELF::R_X86_64_TLSLD;
  88           break;
  89         }
  90         break;
  91       case FK_PCRel_2:
  92         assert(Modifier == MCSymbolRefExpr::VK_None);
  93         Type = ELF::R_X86_64_PC16;
  94         break;
  95       case FK_PCRel_1:
  96         assert(Modifier == MCSymbolRefExpr::VK_None);
  97         Type = ELF::R_X86_64_PC8;
  98         break;
  99       }
 100     } else {
 101       switch ((unsigned)Fixup.getKind()) {
 102       default: llvm_unreachable("invalid fixup kind!");
 103       case FK_Data_8: Type = ELF::R_X86_64_64; break;
 104       case X86::reloc_signed_4byte:
 105         switch (Modifier) {
 106         default:
 107           llvm_unreachable("Unimplemented");
 108         case MCSymbolRefExpr::VK_None:
 109           Type = ELF::R_X86_64_32S;
 110           break;
 111         case MCSymbolRefExpr::VK_GOT:
 112           Type = ELF::R_X86_64_GOT32;
 113           break;
 114         case MCSymbolRefExpr::VK_GOTPCREL:
 115           Type = ELF::R_X86_64_GOTPCREL;
 116           break;
 117         case MCSymbolRefExpr::VK_TPOFF:
 118           Type = ELF::R_X86_64_TPOFF32;
 119           break;
 120         case MCSymbolRefExpr::VK_DTPOFF:
 121           Type = ELF::R_X86_64_DTPOFF32;
 122           break;
 123         }
 124         break;
 125       case FK_Data_4:
 126         Type = ELF::R_X86_64_32;
 127         break;
 128       case FK_Data_2: Type = ELF::R_X86_64_16; break;
 129       case FK_PCRel_1:
 130       case FK_Data_1: Type = ELF::R_X86_64_8; break;
 131       }
 132     }
 133   } else {
 134     if (IsPCRel) {
 135       switch ((unsigned)Fixup.getKind()) {
 136       default: llvm_unreachable("invalid fixup kind!");
 137
 138       case X86::reloc_global_offset_table:
 139         Type = ELF::R_386_GOTPC;
 140         break;
 141
 142       case X86::reloc_signed_4byte:
 143       case FK_PCRel_4:
 144       case FK_Data_4:
 145         switch (Modifier) {
 146         default:
 147           llvm_unreachable("Unimplemented");
 148         case MCSymbolRefExpr::VK_None:
 149           Type = ELF::R_386_PC32;
 150           break;
 151         case MCSymbolRefExpr::VK_PLT:
 152           Type = ELF::R_386_PLT32;
 153           break;
 154         }
 155         break;
 156       }
 157     } else {
 158       switch ((unsigned)Fixup.getKind()) {
 159       default: llvm_unreachable("invalid fixup kind!");
 160
 161       case X86::reloc_global_offset_table:
 162         Type = ELF::R_386_GOTPC;
 163         break;
 164
 165       // FIXME: Should we avoid selecting reloc_signed_4byte in 32 bit mode
 166       // instead?
 167       case X86::reloc_signed_4byte:
 168       case FK_PCRel_4:
 169       case FK_Data_4:
 170         switch (Modifier) {
 171         default:
 172           llvm_unreachable("Unimplemented");
 173         case MCSymbolRefExpr::VK_None:
 174           Type = ELF::R_386_32;
 175           break;
 176         case MCSymbolRefExpr::VK_GOT:
 177           Type = ELF::R_386_GOT32;
 178           break;
 179         case MCSymbolRefExpr::VK_GOTOFF:
 180           Type = ELF::R_386_GOTOFF;
 181           break;
 182         case MCSymbolRefExpr::VK_TLSGD:
 183           Type = ELF::R_386_TLS_GD;
 184           break;
 185         case MCSymbolRefExpr::VK_TPOFF:
 186           Type = ELF::R_386_TLS_LE_32;
 187           break;
 188         case MCSymbolRefExpr::VK_INDNTPOFF:
 189           Type = ELF::R_386_TLS_IE;
 190           break;
 191         case MCSymbolRefExpr::VK_NTPOFF:
 192           Type = ELF::R_386_TLS_LE;
 193           break;
 194         case MCSymbolRefExpr::VK_GOTNTPOFF:
 195           Type = ELF::R_386_TLS_GOTIE;
 196           break;
 197         case MCSymbolRefExpr::VK_TLSLDM:
 198           Type = ELF::R_386_TLS_LDM;
 199           break;
 200         case MCSymbolRefExpr::VK_DTPOFF:
 201           Type = ELF::R_386_TLS_LDO_32;
 202           break;
 203         case MCSymbolRefExpr::VK_GOTTPOFF:
 204           Type = ELF::R_386_TLS_IE_32;
 205           break;
 206         }
 207         break;
 208       case FK_Data_2: Type = ELF::R_386_16; break;
 209       case FK_PCRel_1:
 210       case FK_Data_1: Type = ELF::R_386_8; break;
 211       }
 212     }
 213   }
 214
 215   return Type;
 216 }
 217
 218 MCObjectWriter *llvm::createX86ELFObjectWriter(raw_ostream &OS,
 219                                                bool Is64Bit,
 220                                                uint8_t OSABI) {
 221   MCELFObjectTargetWriter *MOTW =
 222     new X86ELFObjectWriter(Is64Bit, OSABI);
 223   return createELFObjectWriter(MOTW, OS,  /*IsLittleEndian=*/true);
 224 }