1 //===-- PPCELFObjectWriter.cpp - PPC 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/PPCMCTargetDesc.h" 11 #include "MCTargetDesc/PPCFixupKinds.h" 12 #include "llvm/ADT/STLExtras.h" 13 #include "llvm/MC/MCELFObjectWriter.h" 14 #include "llvm/MC/MCExpr.h" 15 #include "llvm/MC/MCValue.h" 16 #include "llvm/Support/ErrorHandling.h" 17 18 using namespace llvm; 19 20 namespace { 21 class PPCELFObjectWriter : public MCELFObjectTargetWriter { 22 public: 23 PPCELFObjectWriter(bool Is64Bit, uint8_t OSABI); 24 25 virtual ~PPCELFObjectWriter(); 26 protected: 27 virtual unsigned getRelocTypeInner(const MCValue &Target, 28 const MCFixup &Fixup, 29 bool IsPCRel) const; 30 virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup, 31 bool IsPCRel, bool IsRelocWithSymbol, 32 int64_t Addend) const; 33 virtual const MCSymbol *undefinedExplicitRelSym(const MCValue &Target, 34 const MCFixup &Fixup, 35 bool IsPCRel) const; 36 virtual void adjustFixupOffset(const MCFixup &Fixup, uint64_t &RelocOffset); 37 38 virtual void sortRelocs(const MCAssembler &Asm, 39 std::vector<ELFRelocationEntry> &Relocs); 40 }; 41 42 class PPCELFRelocationEntry : public ELFRelocationEntry { 43 public: 44 PPCELFRelocationEntry(const ELFRelocationEntry &RE); 45 bool operator<(const PPCELFRelocationEntry &RE) const { 46 return (RE.r_offset < r_offset || 47 (RE.r_offset == r_offset && RE.Type > Type)); 48 } 49 }; 50 } 51 52 PPCELFRelocationEntry::PPCELFRelocationEntry(const ELFRelocationEntry &RE) 53 : ELFRelocationEntry(RE.r_offset, RE.Index, RE.Type, RE.Symbol, 54 RE.r_addend, *RE.Fixup) {} 55 56 PPCELFObjectWriter::PPCELFObjectWriter(bool Is64Bit, uint8_t OSABI) 57 : MCELFObjectTargetWriter(Is64Bit, OSABI, 58 Is64Bit ? ELF::EM_PPC64 : ELF::EM_PPC, 59 /*HasRelocationAddend*/ true) {} 60 61 PPCELFObjectWriter::~PPCELFObjectWriter() { 62 } 63 64 unsigned PPCELFObjectWriter::getRelocTypeInner(const MCValue &Target, 65 const MCFixup &Fixup, 66 bool IsPCRel) const 67 { 68 MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ? 69 MCSymbolRefExpr::VK_None : Target.getSymA()->getKind(); 70 71 // determine the type of the relocation 72 unsigned Type; 73 if (IsPCRel) { 74 switch ((unsigned)Fixup.getKind()) { 75 default: 76 llvm_unreachable("Unimplemented"); 77 case PPC::fixup_ppc_br24: 78 Type = ELF::R_PPC_REL24; 79 break; 80 case FK_PCRel_4: 81 Type = ELF::R_PPC_REL32; 82 break; 83 } 84 } else { 85 switch ((unsigned)Fixup.getKind()) { 86 default: llvm_unreachable("invalid fixup kind!"); 87 case PPC::fixup_ppc_br24: 88 Type = ELF::R_PPC_ADDR24; 89 break; 90 case PPC::fixup_ppc_brcond14: 91 Type = ELF::R_PPC_ADDR14; // XXX: or BRNTAKEN?_ 92 break; 93 case PPC::fixup_ppc_ha16: 94 switch (Modifier) { 95 default: llvm_unreachable("Unsupported Modifier"); 96 case MCSymbolRefExpr::VK_PPC_TPREL16_HA: 97 Type = ELF::R_PPC_TPREL16_HA; 98 break; 99 case MCSymbolRefExpr::VK_PPC_DTPREL16_HA: 100 Type = ELF::R_PPC64_DTPREL16_HA; 101 break; 102 case MCSymbolRefExpr::VK_None: 103 Type = ELF::R_PPC_ADDR16_HA; 104 break; 105 case MCSymbolRefExpr::VK_PPC_TOC16_HA: 106 Type = ELF::R_PPC64_TOC16_HA; 107 break; 108 case MCSymbolRefExpr::VK_PPC_GOT_TPREL16_HA: 109 Type = ELF::R_PPC64_GOT_TPREL16_HA; 110 break; 111 case MCSymbolRefExpr::VK_PPC_GOT_TLSGD16_HA: 112 Type = ELF::R_PPC64_GOT_TLSGD16_HA; 113 break; 114 case MCSymbolRefExpr::VK_PPC_GOT_TLSLD16_HA: 115 Type = ELF::R_PPC64_GOT_TLSLD16_HA; 116 break; 117 } 118 break; 119 case PPC::fixup_ppc_lo16: 120 switch (Modifier) { 121 default: llvm_unreachable("Unsupported Modifier"); 122 case MCSymbolRefExpr::VK_PPC_TPREL16_LO: 123 Type = ELF::R_PPC_TPREL16_LO; 124 break; 125 case MCSymbolRefExpr::VK_PPC_DTPREL16_LO: 126 Type = ELF::R_PPC64_DTPREL16_LO; 127 break; 128 case MCSymbolRefExpr::VK_None: 129 Type = ELF::R_PPC_ADDR16_LO; 130 break; 131 case MCSymbolRefExpr::VK_PPC_TOC16_LO: 132 Type = ELF::R_PPC64_TOC16_LO; 133 break; 134 case MCSymbolRefExpr::VK_PPC_GOT_TLSGD16_LO: 135 Type = ELF::R_PPC64_GOT_TLSGD16_LO; 136 break; 137 case MCSymbolRefExpr::VK_PPC_GOT_TLSLD16_LO: 138 Type = ELF::R_PPC64_GOT_TLSLD16_LO; 139 break; 140 } 141 break; 142 case PPC::fixup_ppc_lo14: 143 Type = ELF::R_PPC_ADDR14; 144 break; 145 case PPC::fixup_ppc_toc: 146 Type = ELF::R_PPC64_TOC; 147 break; 148 case PPC::fixup_ppc_toc16: 149 Type = ELF::R_PPC64_TOC16; 150 break; 151 case PPC::fixup_ppc_toc16_ds: 152 switch (Modifier) { 153 default: llvm_unreachable("Unsupported Modifier"); 154 case MCSymbolRefExpr::VK_PPC_TOC_ENTRY: 155 Type = ELF::R_PPC64_TOC16_DS; 156 break; 157 case MCSymbolRefExpr::VK_PPC_TOC16_LO: 158 Type = ELF::R_PPC64_TOC16_LO_DS; 159 break; 160 case MCSymbolRefExpr::VK_PPC_GOT_TPREL16_LO: 161 Type = ELF::R_PPC64_GOT_TPREL16_LO_DS; 162 break; 163 } 164 break; 165 case PPC::fixup_ppc_tlsreg: 166 Type = ELF::R_PPC64_TLS; 167 break; 168 case PPC::fixup_ppc_nofixup: 169 switch (Modifier) { 170 default: llvm_unreachable("Unsupported Modifier"); 171 case MCSymbolRefExpr::VK_PPC_TLSGD: 172 Type = ELF::R_PPC64_TLSGD; 173 break; 174 case MCSymbolRefExpr::VK_PPC_TLSLD: 175 Type = ELF::R_PPC64_TLSLD; 176 break; 177 } 178 break; 179 case FK_Data_8: 180 switch (Modifier) { 181 default: llvm_unreachable("Unsupported Modifier"); 182 case MCSymbolRefExpr::VK_PPC_TOC: 183 Type = ELF::R_PPC64_TOC; 184 break; 185 case MCSymbolRefExpr::VK_None: 186 Type = ELF::R_PPC64_ADDR64; 187 break; 188 } 189 break; 190 case FK_Data_4: 191 Type = ELF::R_PPC_ADDR32; 192 break; 193 case FK_Data_2: 194 Type = ELF::R_PPC_ADDR16; 195 break; 196 } 197 } 198 return Type; 199 } 200 201 unsigned PPCELFObjectWriter::GetRelocType(const MCValue &Target, 202 const MCFixup &Fixup, 203 bool IsPCRel, 204 bool IsRelocWithSymbol, 205 int64_t Addend) const { 206 return getRelocTypeInner(Target, Fixup, IsPCRel); 207 } 208 209 const MCSymbol *PPCELFObjectWriter::undefinedExplicitRelSym(const MCValue &Target, 210 const MCFixup &Fixup, 211 bool IsPCRel) const { 212 assert(Target.getSymA() && "SymA cannot be 0"); 213 const MCSymbol &Symbol = Target.getSymA()->getSymbol().AliasedSymbol(); 214 215 unsigned RelocType = getRelocTypeInner(Target, Fixup, IsPCRel); 216 217 // The .odp creation emits a relocation against the symbol ".TOC." which 218 // create a R_PPC64_TOC relocation. However the relocation symbol name 219 // in final object creation should be NULL, since the symbol does not 220 // really exist, it is just the reference to TOC base for the current 221 // object file. 222 bool EmitThisSym = RelocType != ELF::R_PPC64_TOC; 223 224 if (EmitThisSym && !Symbol.isTemporary()) 225 return &Symbol; 226 return NULL; 227 } 228 229 void PPCELFObjectWriter:: 230 adjustFixupOffset(const MCFixup &Fixup, uint64_t &RelocOffset) { 231 switch ((unsigned)Fixup.getKind()) { 232 case PPC::fixup_ppc_ha16: 233 case PPC::fixup_ppc_lo16: 234 case PPC::fixup_ppc_toc16: 235 case PPC::fixup_ppc_toc16_ds: 236 RelocOffset += 2; 237 break; 238 default: 239 break; 240 } 241 } 242 243 // The standard sorter only sorts on the r_offset field, but PowerPC can 244 // have multiple relocations at the same offset. Sort secondarily on the 245 // relocation type to avoid nondeterminism. 246 void PPCELFObjectWriter::sortRelocs(const MCAssembler &Asm, 247 std::vector<ELFRelocationEntry> &Relocs) { 248 249 // Copy to a temporary vector of relocation entries having a different 250 // sort function. 251 std::vector<PPCELFRelocationEntry> TmpRelocs; 252 253 for (std::vector<ELFRelocationEntry>::iterator R = Relocs.begin(); 254 R != Relocs.end(); ++R) { 255 TmpRelocs.push_back(PPCELFRelocationEntry(*R)); 256 } 257 258 // Sort in place by ascending r_offset and descending r_type. 259 array_pod_sort(TmpRelocs.begin(), TmpRelocs.end()); 260 261 // Copy back to the original vector. 262 unsigned I = 0; 263 for (std::vector<PPCELFRelocationEntry>::iterator R = TmpRelocs.begin(); 264 R != TmpRelocs.end(); ++R, ++I) { 265 Relocs[I] = ELFRelocationEntry(R->r_offset, R->Index, R->Type, 266 R->Symbol, R->r_addend, *R->Fixup); 267 } 268 } 269 270 271 MCObjectWriter *llvm::createPPCELFObjectWriter(raw_ostream &OS, 272 bool Is64Bit, 273 uint8_t OSABI) { 274 MCELFObjectTargetWriter *MOTW = new PPCELFObjectWriter(Is64Bit, OSABI); 275 return createELFObjectWriter(MOTW, OS, /*IsLittleEndian=*/false); 276 } 277