RelocationValueRef RuntimeDyldMachO::getRelocationValueRef( const ObjectFile &BaseTObj, const relocation_iterator &RI, const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID) { const MachOObjectFile &Obj = static_cast<const MachOObjectFile &>(BaseTObj); MachO::any_relocation_info RelInfo = Obj.getRelocation(RI->getRawDataRefImpl()); RelocationValueRef Value; bool IsExternal = Obj.getPlainRelocationExternal(RelInfo); if (IsExternal) { symbol_iterator Symbol = RI->getSymbol(); StringRef TargetName; Symbol->getName(TargetName); SymbolTableMap::const_iterator SI = GlobalSymbolTable.find(TargetName.data()); if (SI != GlobalSymbolTable.end()) { Value.SectionID = SI->second.first; Value.Offset = SI->second.second + RE.Addend; } else { Value.SymbolName = TargetName.data(); Value.Offset = RE.Addend; } } else { SectionRef Sec = Obj.getRelocationSection(RelInfo); bool IsCode = Sec.isText(); Value.SectionID = findOrEmitSection(Obj, Sec, IsCode, ObjSectionToID); uint64_t Addr = Sec.getAddress(); Value.Offset = RE.Addend - Addr; } return Value; }
RelocationValueRef RuntimeDyldMachO::getRelocationValueRef( const ObjectFile &BaseTObj, const relocation_iterator &RI, const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID) { const MachOObjectFile &Obj = static_cast<const MachOObjectFile &>(BaseTObj); MachO::any_relocation_info RelInfo = Obj.getRelocation(RI->getRawDataRefImpl()); RelocationValueRef Value; bool IsExternal = Obj.getPlainRelocationExternal(RelInfo); if (IsExternal) { symbol_iterator Symbol = RI->getSymbol(); ErrorOr<StringRef> TargetNameOrErr = Symbol->getName(); if (std::error_code EC = TargetNameOrErr.getError()) report_fatal_error(EC.message()); StringRef TargetName = *TargetNameOrErr; RTDyldSymbolTable::const_iterator SI = GlobalSymbolTable.find(TargetName.data()); if (SI != GlobalSymbolTable.end()) { const auto &SymInfo = SI->second; Value.SectionID = SymInfo.getSectionID(); Value.Offset = SymInfo.getOffset() + RE.Addend; } else { Value.SymbolName = TargetName.data(); Value.Offset = RE.Addend; } } else { SectionRef Sec = Obj.getAnyRelocationSection(RelInfo); bool IsCode = Sec.isText(); Value.SectionID = findOrEmitSection(Obj, Sec, IsCode, ObjSectionToID); uint64_t Addr = Sec.getAddress(); Value.Offset = RE.Addend - Addr; } return Value; }
relocation_iterator RuntimeDyldMachO::processRelocationRef( unsigned SectionID, relocation_iterator RelI, ObjectImage &Obj, ObjSectionToIDMap &ObjSectionToID, const SymbolTableMap &Symbols, StubMap &Stubs) { const ObjectFile *OF = Obj.getObjectFile(); const MachOObjectFile *MachO = static_cast<const MachOObjectFile *>(OF); MachO::any_relocation_info RE = MachO->getRelocation(RelI->getRawDataRefImpl()); uint32_t RelType = MachO->getAnyRelocationType(RE); // FIXME: Properly handle scattered relocations. // For now, optimistically skip these: they can often be ignored, as // the static linker will already have applied the relocation, and it // only needs to be reapplied if symbols move relative to one another. // Note: This will fail horribly where the relocations *do* need to be // applied, but that was already the case. if (MachO->isRelocationScattered(RE)) return ++RelI; RelocationValueRef Value; SectionEntry &Section = Sections[SectionID]; bool isExtern = MachO->getPlainRelocationExternal(RE); bool IsPCRel = MachO->getAnyRelocationPCRel(RE); unsigned Size = MachO->getAnyRelocationLength(RE); uint64_t Offset; RelI->getOffset(Offset); uint8_t *LocalAddress = Section.Address + Offset; unsigned NumBytes = 1 << Size; uint64_t Addend = 0; memcpy(&Addend, LocalAddress, NumBytes); if (isExtern) { // Obtain the symbol name which is referenced in the relocation symbol_iterator Symbol = RelI->getSymbol(); StringRef TargetName; Symbol->getName(TargetName); // First search for the symbol in the local symbol table SymbolTableMap::const_iterator lsi = Symbols.find(TargetName.data()); if (lsi != Symbols.end()) { Value.SectionID = lsi->second.first; Value.Addend = lsi->second.second + Addend; } else { // Search for the symbol in the global symbol table SymbolTableMap::const_iterator gsi = GlobalSymbolTable.find(TargetName.data()); if (gsi != GlobalSymbolTable.end()) { Value.SectionID = gsi->second.first; Value.Addend = gsi->second.second + Addend; } else { Value.SymbolName = TargetName.data(); Value.Addend = Addend; } } } else { SectionRef Sec = MachO->getRelocationSection(RE); bool IsCode = false; Sec.isText(IsCode); Value.SectionID = findOrEmitSection(Obj, Sec, IsCode, ObjSectionToID); uint64_t Addr; Sec.getAddress(Addr); Value.Addend = Addend - Addr; if (IsPCRel) Value.Addend += Offset + NumBytes; } if (Arch == Triple::x86_64 && (RelType == MachO::X86_64_RELOC_GOT || RelType == MachO::X86_64_RELOC_GOT_LOAD)) { assert(IsPCRel); assert(Size == 2); StubMap::const_iterator i = Stubs.find(Value); uint8_t *Addr; if (i != Stubs.end()) { Addr = Section.Address + i->second; } else { Stubs[Value] = Section.StubOffset; uint8_t *GOTEntry = Section.Address + Section.StubOffset; RelocationEntry RE(SectionID, Section.StubOffset, MachO::X86_64_RELOC_UNSIGNED, 0, false, 3); if (Value.SymbolName) addRelocationForSymbol(RE, Value.SymbolName); else addRelocationForSection(RE, Value.SectionID); Section.StubOffset += 8; Addr = GOTEntry; } resolveRelocation(Section, Offset, (uint64_t)Addr, MachO::X86_64_RELOC_UNSIGNED, Value.Addend, true, 2); } else if (Arch == Triple::arm && (RelType & 0xf) == MachO::ARM_RELOC_BR24) { // This is an ARM branch relocation, need to use a stub function. // Look up for existing stub. StubMap::const_iterator i = Stubs.find(Value); if (i != Stubs.end()) resolveRelocation(Section, Offset, (uint64_t)Section.Address + i->second, RelType, 0, IsPCRel, Size); else { // Create a new stub function. Stubs[Value] = Section.StubOffset; uint8_t *StubTargetAddr = createStubFunction(Section.Address + Section.StubOffset); RelocationEntry RE(SectionID, StubTargetAddr - Section.Address, MachO::GENERIC_RELOC_VANILLA, Value.Addend); if (Value.SymbolName) addRelocationForSymbol(RE, Value.SymbolName); else addRelocationForSection(RE, Value.SectionID); resolveRelocation(Section, Offset, (uint64_t)Section.Address + Section.StubOffset, RelType, 0, IsPCRel, Size); Section.StubOffset += getMaxStubSize(); } } else { RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, IsPCRel, Size); if (Value.SymbolName) addRelocationForSymbol(RE, Value.SymbolName); else addRelocationForSection(RE, Value.SectionID); } return ++RelI; }