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/PPCFixupKinds.h" 11 #include "MCTargetDesc/PPCMCTargetDesc.h" 12 #include "llvm/MC/MCELFObjectWriter.h" 13 #include "llvm/Support/ErrorHandling.h" 14 #include "llvm/MC/MCExpr.h" 15 #include "llvm/MC/MCValue.h" 16 17 using namespace llvm; 18 19 namespace { 20 class PPCELFObjectWriter : public MCELFObjectTargetWriter { 21 public: 22 PPCELFObjectWriter(bool Is64Bit, uint8_t OSABI); 23 24 virtual ~PPCELFObjectWriter(); 25 protected: 26 virtual unsigned getRelocTypeInner(const MCValue &Target, 27 const MCFixup &Fixup, 28 bool IsPCRel) const; 29 virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup, 30 bool IsPCRel, bool IsRelocWithSymbol, 31 int64_t Addend) const; 32 virtual const MCSymbol *undefinedExplicitRelSym(const MCValue &Target, 33 const MCFixup &Fixup, 34 bool IsPCRel) const; 35 virtual void adjustFixupOffset(const MCFixup &Fixup, uint64_t &RelocOffset); 36 }; 37 } 38 39 PPCELFObjectWriter::PPCELFObjectWriter(bool Is64Bit, uint8_t OSABI) 40 : MCELFObjectTargetWriter(Is64Bit, OSABI, 41 Is64Bit ? ELF::EM_PPC64 : ELF::EM_PPC, 42 /*HasRelocationAddend*/ true) {} 43 44 PPCELFObjectWriter::~PPCELFObjectWriter() { 45 } 46 47 unsigned PPCELFObjectWriter::getRelocTypeInner(const MCValue &Target, 48 const MCFixup &Fixup, 49 bool IsPCRel) const 50 { 51 MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ? 52 MCSymbolRefExpr::VK_None : Target.getSymA()->getKind(); 53 54 // determine the type of the relocation 55 unsigned Type; 56 if (IsPCRel) { 57 switch ((unsigned)Fixup.getKind()) { 58 default: 59 llvm_unreachable("Unimplemented"); 60 case PPC::fixup_ppc_br24: 61 Type = ELF::R_PPC_REL24; 62 break; 63 case FK_PCRel_4: 64 Type = ELF::R_PPC_REL32; 65 break; 66 } 67 } else { 68 switch ((unsigned)Fixup.getKind()) { 69 default: llvm_unreachable("invalid fixup kind!"); 70 case PPC::fixup_ppc_br24: 71 Type = ELF::R_PPC_ADDR24; 72 break; 73 case PPC::fixup_ppc_brcond14: 74 Type = ELF::R_PPC_ADDR14; // XXX: or BRNTAKEN?_ 75 break; 76 case PPC::fixup_ppc_ha16: 77 switch (Modifier) { 78 default: llvm_unreachable("Unsupported Modifier"); 79 case MCSymbolRefExpr::VK_PPC_TPREL16_HA: 80 Type = ELF::R_PPC_TPREL16_HA; 81 break; 82 case MCSymbolRefExpr::VK_None: 83 Type = ELF::R_PPC_ADDR16_HA; 84 break; 85 } 86 break; 87 case PPC::fixup_ppc_lo16: 88 switch (Modifier) { 89 default: llvm_unreachable("Unsupported Modifier"); 90 case MCSymbolRefExpr::VK_PPC_TPREL16_LO: 91 Type = ELF::R_PPC_TPREL16_LO; 92 break; 93 case MCSymbolRefExpr::VK_None: 94 Type = ELF::R_PPC_ADDR16_LO; 95 break; 96 } 97 break; 98 case PPC::fixup_ppc_lo14: 99 Type = ELF::R_PPC_ADDR14; 100 break; 101 case PPC::fixup_ppc_toc: 102 Type = ELF::R_PPC64_TOC; 103 break; 104 case PPC::fixup_ppc_toc16: 105 Type = ELF::R_PPC64_TOC16; 106 break; 107 case PPC::fixup_ppc_toc16_ds: 108 Type = ELF::R_PPC64_TOC16_DS; 109 break; 110 case FK_Data_8: 111 switch (Modifier) { 112 default: llvm_unreachable("Unsupported Modifier"); 113 case MCSymbolRefExpr::VK_PPC_TOC: 114 Type = ELF::R_PPC64_TOC; 115 break; 116 case MCSymbolRefExpr::VK_None: 117 Type = ELF::R_PPC64_ADDR64; 118 break; 119 } 120 break; 121 case FK_Data_4: 122 Type = ELF::R_PPC_ADDR32; 123 break; 124 case FK_Data_2: 125 Type = ELF::R_PPC_ADDR16; 126 break; 127 } 128 } 129 return Type; 130 } 131 132 unsigned PPCELFObjectWriter::GetRelocType(const MCValue &Target, 133 const MCFixup &Fixup, 134 bool IsPCRel, 135 bool IsRelocWithSymbol, 136 int64_t Addend) const { 137 return getRelocTypeInner(Target, Fixup, IsPCRel); 138 } 139 140 const MCSymbol *PPCELFObjectWriter::undefinedExplicitRelSym(const MCValue &Target, 141 const MCFixup &Fixup, 142 bool IsPCRel) const { 143 assert(Target.getSymA() && "SymA cannot be 0"); 144 const MCSymbol &Symbol = Target.getSymA()->getSymbol().AliasedSymbol(); 145 146 unsigned RelocType = getRelocTypeInner(Target, Fixup, IsPCRel); 147 148 // The .odp creation emits a relocation against the symbol ".TOC." which 149 // create a R_PPC64_TOC relocation. However the relocation symbol name 150 // in final object creation should be NULL, since the symbol does not 151 // really exist, it is just the reference to TOC base for the current 152 // object file. 153 bool EmitThisSym = RelocType != ELF::R_PPC64_TOC; 154 155 if (EmitThisSym && !Symbol.isTemporary()) 156 return &Symbol; 157 return NULL; 158 } 159 160 void PPCELFObjectWriter:: 161 adjustFixupOffset(const MCFixup &Fixup, uint64_t &RelocOffset) { 162 switch ((unsigned)Fixup.getKind()) { 163 case PPC::fixup_ppc_ha16: 164 case PPC::fixup_ppc_lo16: 165 case PPC::fixup_ppc_toc16: 166 case PPC::fixup_ppc_toc16_ds: 167 RelocOffset += 2; 168 break; 169 default: 170 break; 171 } 172 } 173 174 MCObjectWriter *llvm::createPPCELFObjectWriter(raw_ostream &OS, 175 bool Is64Bit, 176 uint8_t OSABI) { 177 MCELFObjectTargetWriter *MOTW = new PPCELFObjectWriter(Is64Bit, OSABI); 178 return createELFObjectWriter(MOTW, OS, /*IsLittleEndian=*/false); 179 } 180