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 Type = ELF::R_PPC_ADDR16_HA; 78 break; 79 case PPC::fixup_ppc_lo16: 80 Type = ELF::R_PPC_ADDR16_LO; 81 break; 82 case PPC::fixup_ppc_lo14: 83 Type = ELF::R_PPC_ADDR14; 84 break; 85 case PPC::fixup_ppc_toc: 86 Type = ELF::R_PPC64_TOC; 87 break; 88 case PPC::fixup_ppc_toc16: 89 Type = ELF::R_PPC64_TOC16; 90 break; 91 case PPC::fixup_ppc_toc16_ds: 92 Type = ELF::R_PPC64_TOC16_DS; 93 break; 94 case FK_Data_8: 95 switch (Modifier) { 96 default: llvm_unreachable("Unsupported Modifier"); 97 case MCSymbolRefExpr::VK_PPC_TOC: 98 Type = ELF::R_PPC64_TOC; 99 break; 100 case MCSymbolRefExpr::VK_None: 101 Type = ELF::R_PPC64_ADDR64; 102 break; 103 } 104 break; 105 case FK_Data_4: 106 Type = ELF::R_PPC_ADDR32; 107 break; 108 case FK_Data_2: 109 Type = ELF::R_PPC_ADDR16; 110 break; 111 } 112 } 113 return Type; 114 } 115 116 unsigned PPCELFObjectWriter::GetRelocType(const MCValue &Target, 117 const MCFixup &Fixup, 118 bool IsPCRel, 119 bool IsRelocWithSymbol, 120 int64_t Addend) const { 121 return getRelocTypeInner(Target, Fixup, IsPCRel); 122 } 123 124 const MCSymbol *PPCELFObjectWriter::undefinedExplicitRelSym(const MCValue &Target, 125 const MCFixup &Fixup, 126 bool IsPCRel) const { 127 assert(Target.getSymA() && "SymA cannot be 0"); 128 const MCSymbol &Symbol = Target.getSymA()->getSymbol().AliasedSymbol(); 129 130 unsigned RelocType = getRelocTypeInner(Target, Fixup, IsPCRel); 131 132 // The .odp creation emits a relocation against the symbol ".TOC." which 133 // create a R_PPC64_TOC relocation. However the relocation symbol name 134 // in final object creation should be NULL, since the symbol does not 135 // really exist, it is just the reference to TOC base for the current 136 // object file. 137 bool EmitThisSym = RelocType != ELF::R_PPC64_TOC; 138 139 if (EmitThisSym && !Symbol.isTemporary()) 140 return &Symbol; 141 return NULL; 142 } 143 144 void PPCELFObjectWriter:: 145 adjustFixupOffset(const MCFixup &Fixup, uint64_t &RelocOffset) { 146 switch ((unsigned)Fixup.getKind()) { 147 case PPC::fixup_ppc_ha16: 148 case PPC::fixup_ppc_lo16: 149 case PPC::fixup_ppc_toc16: 150 case PPC::fixup_ppc_toc16_ds: 151 RelocOffset += 2; 152 break; 153 default: 154 break; 155 } 156 } 157 158 MCObjectWriter *llvm::createPPCELFObjectWriter(raw_ostream &OS, 159 bool Is64Bit, 160 uint8_t OSABI) { 161 MCELFObjectTargetWriter *MOTW = new PPCELFObjectWriter(Is64Bit, OSABI); 162 return createELFObjectWriter(MOTW, OS, /*IsLittleEndian=*/false); 163 } 164