| //===-- RuntimeDyldELF.cpp - Run-time dynamic linker for MC-JIT -*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // Implementation of ELF support for the MC-JIT runtime dynamic linker. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "RuntimeDyldELF.h" |
| #include "RuntimeDyldCheckerImpl.h" |
| #include "Targets/RuntimeDyldELFMips.h" |
| #include "llvm/ADT/IntervalMap.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/ADT/StringRef.h" |
| #include "llvm/ADT/Triple.h" |
| #include "llvm/BinaryFormat/ELF.h" |
| #include "llvm/MC/MCStreamer.h" |
| #include "llvm/Object/ELFObjectFile.h" |
| #include "llvm/Object/ObjectFile.h" |
| #include "llvm/Support/Endian.h" |
| #include "llvm/Support/MemoryBuffer.h" |
| #include "llvm/Support/TargetRegistry.h" |
| |
| using namespace llvm; |
| using namespace llvm::object; |
| using namespace llvm::support::endian; |
| |
| #define DEBUG_TYPE "dyld" |
| |
| static void or32le(void *P, int32_t V) { write32le(P, read32le(P) | V); } |
| |
| static void or32AArch64Imm(void *L, uint64_t Imm) { |
| or32le(L, (Imm & 0xFFF) << 10); |
| } |
| |
| template <class T> static void write(bool isBE, void *P, T V) { |
| isBE ? write<T, support::big>(P, V) : write<T, support::little>(P, V); |
| } |
| |
| static void write32AArch64Addr(void *L, uint64_t Imm) { |
| uint32_t ImmLo = (Imm & 0x3) << 29; |
| uint32_t ImmHi = (Imm & 0x1FFFFC) << 3; |
| uint64_t Mask = (0x3 << 29) | (0x1FFFFC << 3); |
| write32le(L, (read32le(L) & ~Mask) | ImmLo | ImmHi); |
| } |
| |
| // Return the bits [Start, End] from Val shifted Start bits. |
| // For instance, getBits(0xF0, 4, 8) returns 0xF. |
| static uint64_t getBits(uint64_t Val, int Start, int End) { |
| uint64_t Mask = ((uint64_t)1 << (End + 1 - Start)) - 1; |
| return (Val >> Start) & Mask; |
| } |
| |
| namespace { |
| |
| template <class ELFT> class DyldELFObject : public ELFObjectFile<ELFT> { |
| LLVM_ELF_IMPORT_TYPES_ELFT(ELFT) |
| |
| typedef Elf_Shdr_Impl<ELFT> Elf_Shdr; |
| typedef Elf_Sym_Impl<ELFT> Elf_Sym; |
| typedef Elf_Rel_Impl<ELFT, false> Elf_Rel; |
| typedef Elf_Rel_Impl<ELFT, true> Elf_Rela; |
| |
| typedef Elf_Ehdr_Impl<ELFT> Elf_Ehdr; |
| |
| typedef typename ELFDataTypeTypedefHelper<ELFT>::value_type addr_type; |
| |
| public: |
| DyldELFObject(MemoryBufferRef Wrapper, std::error_code &ec); |
| |
| void updateSectionAddress(const SectionRef &Sec, uint64_t Addr); |
| |
| void updateSymbolAddress(const SymbolRef &SymRef, uint64_t Addr); |
| |
| // Methods for type inquiry through isa, cast and dyn_cast |
| static bool classof(const Binary *v) { |
| return (isa<ELFObjectFile<ELFT>>(v) && |
| classof(cast<ELFObjectFile<ELFT>>(v))); |
| } |
| static bool classof(const ELFObjectFile<ELFT> *v) { |
| return v->isDyldType(); |
| } |
| }; |
| |
| |
| |
| // The MemoryBuffer passed into this constructor is just a wrapper around the |
| // actual memory. Ultimately, the Binary parent class will take ownership of |
| // this MemoryBuffer object but not the underlying memory. |
| template <class ELFT> |
| DyldELFObject<ELFT>::DyldELFObject(MemoryBufferRef Wrapper, std::error_code &EC) |
| : ELFObjectFile<ELFT>(Wrapper, EC) { |
| this->isDyldELFObject = true; |
| } |
| |
| template <class ELFT> |
| void DyldELFObject<ELFT>::updateSectionAddress(const SectionRef &Sec, |
| uint64_t Addr) { |
| DataRefImpl ShdrRef = Sec.getRawDataRefImpl(); |
| Elf_Shdr *shdr = |
| const_cast<Elf_Shdr *>(reinterpret_cast<const Elf_Shdr *>(ShdrRef.p)); |
| |
| // This assumes the address passed in matches the target address bitness |
| // The template-based type cast handles everything else. |
| shdr->sh_addr = static_cast<addr_type>(Addr); |
| } |
| |
| template <class ELFT> |
| void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef, |
| uint64_t Addr) { |
| |
| Elf_Sym *sym = const_cast<Elf_Sym *>( |
| ELFObjectFile<ELFT>::getSymbol(SymRef.getRawDataRefImpl())); |
| |
| // This assumes the address passed in matches the target address bitness |
| // The template-based type cast handles everything else. |
| sym->st_value = static_cast<addr_type>(Addr); |
| } |
| |
| class LoadedELFObjectInfo final |
| : public LoadedObjectInfoHelper<LoadedELFObjectInfo, |
| RuntimeDyld::LoadedObjectInfo> { |
| public: |
| LoadedELFObjectInfo(RuntimeDyldImpl &RTDyld, ObjSectionToIDMap ObjSecToIDMap) |
| : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {} |
| |
| OwningBinary<ObjectFile> |
| getObjectForDebug(const ObjectFile &Obj) const override; |
| }; |
| |
| template <typename ELFT> |
| std::unique_ptr<DyldELFObject<ELFT>> |
| createRTDyldELFObject(MemoryBufferRef Buffer, |
| const ObjectFile &SourceObject, |
| const LoadedELFObjectInfo &L, |
| std::error_code &ec) { |
| typedef typename ELFFile<ELFT>::Elf_Shdr Elf_Shdr; |
| typedef typename ELFDataTypeTypedefHelper<ELFT>::value_type addr_type; |
| |
| std::unique_ptr<DyldELFObject<ELFT>> Obj = |
| llvm::make_unique<DyldELFObject<ELFT>>(Buffer, ec); |
| |
| // Iterate over all sections in the object. |
| auto SI = SourceObject.section_begin(); |
| for (const auto &Sec : Obj->sections()) { |
| StringRef SectionName; |
| Sec.getName(SectionName); |
| if (SectionName != "") { |
| DataRefImpl ShdrRef = Sec.getRawDataRefImpl(); |
| Elf_Shdr *shdr = const_cast<Elf_Shdr *>( |
| reinterpret_cast<const Elf_Shdr *>(ShdrRef.p)); |
| |
| if (uint64_t SecLoadAddr = L.getSectionLoadAddress(*SI)) { |
| // This assumes that the address passed in matches the target address |
| // bitness. The template-based type cast handles everything else. |
| shdr->sh_addr = static_cast<addr_type>(SecLoadAddr); |
| } |
| } |
| ++SI; |
| } |
| |
| return Obj; |
| } |
| |
| OwningBinary<ObjectFile> createELFDebugObject(const ObjectFile &Obj, |
| const LoadedELFObjectInfo &L) { |
| assert(Obj.isELF() && "Not an ELF object file."); |
| |
| std::unique_ptr<MemoryBuffer> Buffer = |
| MemoryBuffer::getMemBufferCopy(Obj.getData(), Obj.getFileName()); |
| |
| std::error_code ec; |
| |
| std::unique_ptr<ObjectFile> DebugObj; |
| if (Obj.getBytesInAddress() == 4 && Obj.isLittleEndian()) { |
| typedef ELFType<support::little, false> ELF32LE; |
| DebugObj = createRTDyldELFObject<ELF32LE>(Buffer->getMemBufferRef(), Obj, L, |
| ec); |
| } else if (Obj.getBytesInAddress() == 4 && !Obj.isLittleEndian()) { |
| typedef ELFType<support::big, false> ELF32BE; |
| DebugObj = createRTDyldELFObject<ELF32BE>(Buffer->getMemBufferRef(), Obj, L, |
| ec); |
| } else if (Obj.getBytesInAddress() == 8 && !Obj.isLittleEndian()) { |
| typedef ELFType<support::big, true> ELF64BE; |
| DebugObj = createRTDyldELFObject<ELF64BE>(Buffer->getMemBufferRef(), Obj, L, |
| ec); |
| } else if (Obj.getBytesInAddress() == 8 && Obj.isLittleEndian()) { |
| typedef ELFType<support::little, true> ELF64LE; |
| DebugObj = createRTDyldELFObject<ELF64LE>(Buffer->getMemBufferRef(), Obj, L, |
| ec); |
| } else |
| llvm_unreachable("Unexpected ELF format"); |
| |
| assert(!ec && "Could not construct copy ELF object file"); |
| |
| return OwningBinary<ObjectFile>(std::move(DebugObj), std::move(Buffer)); |
| } |
| |
| OwningBinary<ObjectFile> |
| LoadedELFObjectInfo::getObjectForDebug(const ObjectFile &Obj) const { |
| return createELFDebugObject(Obj, *this); |
| } |
| |
| } // anonymous namespace |
| |
| namespace llvm { |
| |
| RuntimeDyldELF::RuntimeDyldELF(RuntimeDyld::MemoryManager &MemMgr, |
| JITSymbolResolver &Resolver) |
| : RuntimeDyldImpl(MemMgr, Resolver), GOTSectionID(0), CurrentGOTIndex(0) {} |
| RuntimeDyldELF::~RuntimeDyldELF() {} |
| |
| void RuntimeDyldELF::registerEHFrames() { |
| for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) { |
| SID EHFrameSID = UnregisteredEHFrameSections[i]; |
| uint8_t *EHFrameAddr = Sections[EHFrameSID].getAddress(); |
| uint64_t EHFrameLoadAddr = Sections[EHFrameSID].getLoadAddress(); |
| size_t EHFrameSize = Sections[EHFrameSID].getSize(); |
| MemMgr.registerEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize); |
| } |
| UnregisteredEHFrameSections.clear(); |
| } |
| |
| std::unique_ptr<RuntimeDyldELF> |
| llvm::RuntimeDyldELF::create(Triple::ArchType Arch, |
| RuntimeDyld::MemoryManager &MemMgr, |
| JITSymbolResolver &Resolver) { |
| switch (Arch) { |
| default: |
| return make_unique<RuntimeDyldELF>(MemMgr, Resolver); |
| case Triple::mips: |
| case Triple::mipsel: |
| case Triple::mips64: |
| case Triple::mips64el: |
| return make_unique<RuntimeDyldELFMips>(MemMgr, Resolver); |
| } |
| } |
| |
| std::unique_ptr<RuntimeDyld::LoadedObjectInfo> |
| RuntimeDyldELF::loadObject(const object::ObjectFile &O) { |
| if (auto ObjSectionToIDOrErr = loadObjectImpl(O)) |
| return llvm::make_unique<LoadedELFObjectInfo>(*this, *ObjSectionToIDOrErr); |
| else { |
| HasError = true; |
| raw_string_ostream ErrStream(ErrorStr); |
| logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream, ""); |
| return nullptr; |
| } |
| } |
| |
| void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section, |
| uint64_t Offset, uint64_t Value, |
| uint32_t Type, int64_t Addend, |
| uint64_t SymOffset) { |
| switch (Type) { |
| default: |
| llvm_unreachable("Relocation type not implemented yet!"); |
| break; |
| case ELF::R_X86_64_NONE: |
| break; |
| case ELF::R_X86_64_64: { |
| support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = |
| Value + Addend; |
| DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at " |
| << format("%p\n", Section.getAddressWithOffset(Offset))); |
| break; |
| } |
| case ELF::R_X86_64_32: |
| case ELF::R_X86_64_32S: { |
| Value += Addend; |
| assert((Type == ELF::R_X86_64_32 && (Value <= UINT32_MAX)) || |
| (Type == ELF::R_X86_64_32S && |
| ((int64_t)Value <= INT32_MAX && (int64_t)Value >= INT32_MIN))); |
| uint32_t TruncatedAddr = (Value & 0xFFFFFFFF); |
| support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = |
| TruncatedAddr; |
| DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr) << " at " |
| << format("%p\n", Section.getAddressWithOffset(Offset))); |
| break; |
| } |
| case ELF::R_X86_64_PC8: { |
| uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); |
| int64_t RealOffset = Value + Addend - FinalAddress; |
| assert(isInt<8>(RealOffset)); |
| int8_t TruncOffset = (RealOffset & 0xFF); |
| Section.getAddress()[Offset] = TruncOffset; |
| break; |
| } |
| case ELF::R_X86_64_PC32: { |
| uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); |
| int64_t RealOffset = Value + Addend - FinalAddress; |
| assert(isInt<32>(RealOffset)); |
| int32_t TruncOffset = (RealOffset & 0xFFFFFFFF); |
| support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = |
| TruncOffset; |
| break; |
| } |
| case ELF::R_X86_64_PC64: { |
| uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); |
| int64_t RealOffset = Value + Addend - FinalAddress; |
| support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) = |
| RealOffset; |
| break; |
| } |
| } |
| } |
| |
| void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section, |
| uint64_t Offset, uint32_t Value, |
| uint32_t Type, int32_t Addend) { |
| switch (Type) { |
| case ELF::R_386_32: { |
| support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = |
| Value + Addend; |
| break; |
| } |
| case ELF::R_386_PC32: { |
| uint32_t FinalAddress = |
| Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF; |
| uint32_t RealOffset = Value + Addend - FinalAddress; |
| support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) = |
| RealOffset; |
| break; |
| } |
| default: |
| // There are other relocation types, but it appears these are the |
| // only ones currently used by the LLVM ELF object writer |
| llvm_unreachable("Relocation type not implemented yet!"); |
| break; |
| } |
| } |
| |
| void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section, |
| uint64_t Offset, uint64_t Value, |
| uint32_t Type, int64_t Addend) { |
| uint32_t *TargetPtr = |
| reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset)); |
| uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); |
| // Data should use target endian. Code should always use little endian. |
| bool isBE = Arch == Triple::aarch64_be; |
| |
| DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x" |
| << format("%llx", Section.getAddressWithOffset(Offset)) |
| << " FinalAddress: 0x" << format("%llx", FinalAddress) |
| << " Value: 0x" << format("%llx", Value) << " Type: 0x" |
| << format("%x", Type) << " Addend: 0x" << format("%llx", Addend) |
| << "\n"); |
| |
| switch (Type) { |
| default: |
| llvm_unreachable("Relocation type not implemented yet!"); |
| break; |
| case ELF::R_AARCH64_ABS64: |
| write(isBE, TargetPtr, Value + Addend); |
| break; |
| case ELF::R_AARCH64_PREL32: { |
| uint64_t Result = Value + Addend - FinalAddress; |
| assert(static_cast<int64_t>(Result) >= INT32_MIN && |
| static_cast<int64_t>(Result) <= UINT32_MAX); |
| write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU)); |
| break; |
| } |
| case ELF::R_AARCH64_PREL64: |
| write(isBE, TargetPtr, Value + Addend - FinalAddress); |
| break; |
| case ELF::R_AARCH64_CALL26: // fallthrough |
| case ELF::R_AARCH64_JUMP26: { |
| // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the |
| // calculation. |
| uint64_t BranchImm = Value + Addend - FinalAddress; |
| |
| // "Check that -2^27 <= result < 2^27". |
| assert(isInt<28>(BranchImm)); |
| or32le(TargetPtr, (BranchImm & 0x0FFFFFFC) >> 2); |
| break; |
| } |
| case ELF::R_AARCH64_MOVW_UABS_G3: |
| or32le(TargetPtr, ((Value + Addend) & 0xFFFF000000000000) >> 43); |
| break; |
| case ELF::R_AARCH64_MOVW_UABS_G2_NC: |
| or32le(TargetPtr, ((Value + Addend) & 0xFFFF00000000) >> 27); |
| break; |
| case ELF::R_AARCH64_MOVW_UABS_G1_NC: |
| or32le(TargetPtr, ((Value + Addend) & 0xFFFF0000) >> 11); |
| break; |
| case ELF::R_AARCH64_MOVW_UABS_G0_NC: |
| or32le(TargetPtr, ((Value + Addend) & 0xFFFF) << 5); |
| break; |
| case ELF::R_AARCH64_ADR_PREL_PG_HI21: { |
| // Operation: Page(S+A) - Page(P) |
| uint64_t Result = |
| ((Value + Addend) & ~0xfffULL) - (FinalAddress & ~0xfffULL); |
| |
| // Check that -2^32 <= X < 2^32 |
| assert(isInt<33>(Result) && "overflow check failed for relocation"); |
| |
| // Immediate goes in bits 30:29 + 5:23 of ADRP instruction, taken |
| // from bits 32:12 of X. |
| write32AArch64Addr(TargetPtr, Result >> 12); |
| break; |
| } |
| case ELF::R_AARCH64_ADD_ABS_LO12_NC: |
| // Operation: S + A |
| // Immediate goes in bits 21:10 of LD/ST instruction, taken |
| // from bits 11:0 of X |
| or32AArch64Imm(TargetPtr, Value + Addend); |
| break; |
| case ELF::R_AARCH64_LDST8_ABS_LO12_NC: |
| // Operation: S + A |
| // Immediate goes in bits 21:10 of LD/ST instruction, taken |
| // from bits 11:0 of X |
| or32AArch64Imm(TargetPtr, getBits(Value + Addend, 0, 11)); |
| break; |
| case ELF::R_AARCH64_LDST16_ABS_LO12_NC: |
| // Operation: S + A |
| // Immediate goes in bits 21:10 of LD/ST instruction, taken |
| // from bits 11:1 of X |
| or32AArch64Imm(TargetPtr, getBits(Value + Addend, 1, 11)); |
| break; |
| case ELF::R_AARCH64_LDST32_ABS_LO12_NC: |
| // Operation: S + A |
| // Immediate goes in bits 21:10 of LD/ST instruction, taken |
| // from bits 11:2 of X |
| or32AArch64Imm(TargetPtr, getBits(Value + Addend, 2, 11)); |
| break; |
| case ELF::R_AARCH64_LDST64_ABS_LO12_NC: |
| // Operation: S + A |
| // Immediate goes in bits 21:10 of LD/ST instruction, taken |
| // from bits 11:3 of X |
| or32AArch64Imm(TargetPtr, getBits(Value + Addend, 3, 11)); |
| break; |
| case ELF::R_AARCH64_LDST128_ABS_LO12_NC: |
| // Operation: S + A |
| // Immediate goes in bits 21:10 of LD/ST instruction, taken |
| // from bits 11:4 of X |
| or32AArch64Imm(TargetPtr, getBits(Value + Addend, 4, 11)); |
| break; |
| } |
| } |
| |
| void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section, |
| uint64_t Offset, uint32_t Value, |
| uint32_t Type, int32_t Addend) { |
| // TODO: Add Thumb relocations. |
| uint32_t *TargetPtr = |
| reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset)); |
| uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF; |
| Value += Addend; |
| |
| DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: " |
| << Section.getAddressWithOffset(Offset) |
| << " FinalAddress: " << format("%p", FinalAddress) << " Value: " |
| << format("%x", Value) << " Type: " << format("%x", Type) |
| << " Addend: " << format("%x", Addend) << "\n"); |
| |
| switch (Type) { |
| default: |
| llvm_unreachable("Not implemented relocation type!"); |
| |
| case ELF::R_ARM_NONE: |
| break; |
| // Write a 31bit signed offset |
| case ELF::R_ARM_PREL31: |
| support::ulittle32_t::ref{TargetPtr} = |
| (support::ulittle32_t::ref{TargetPtr} & 0x80000000) | |
| ((Value - FinalAddress) & ~0x80000000); |
| break; |
| case ELF::R_ARM_TARGET1: |
| case ELF::R_ARM_ABS32: |
| support::ulittle32_t::ref{TargetPtr} = Value; |
| break; |
| // Write first 16 bit of 32 bit value to the mov instruction. |
| // Last 4 bit should be shifted. |
| case ELF::R_ARM_MOVW_ABS_NC: |
| case ELF::R_ARM_MOVT_ABS: |
| if (Type == ELF::R_ARM_MOVW_ABS_NC) |
| Value = Value & 0xFFFF; |
| else if (Type == ELF::R_ARM_MOVT_ABS) |
| Value = (Value >> 16) & 0xFFFF; |
| support::ulittle32_t::ref{TargetPtr} = |
| (support::ulittle32_t::ref{TargetPtr} & ~0x000F0FFF) | (Value & 0xFFF) | |
| (((Value >> 12) & 0xF) << 16); |
| break; |
| // Write 24 bit relative value to the branch instruction. |
| case ELF::R_ARM_PC24: // Fall through. |
| case ELF::R_ARM_CALL: // Fall through. |
| case ELF::R_ARM_JUMP24: |
| int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8); |
| RelValue = (RelValue & 0x03FFFFFC) >> 2; |
| assert((support::ulittle32_t::ref{TargetPtr} & 0xFFFFFF) == 0xFFFFFE); |
| support::ulittle32_t::ref{TargetPtr} = |
| (support::ulittle32_t::ref{TargetPtr} & 0xFF000000) | RelValue; |
| break; |
| } |
| } |
| |
| void RuntimeDyldELF::setMipsABI(const ObjectFile &Obj) { |
| if (Arch == Triple::UnknownArch || |
| !StringRef(Triple::getArchTypePrefix(Arch)).equals("mips")) { |
| IsMipsO32ABI = false; |
| IsMipsN32ABI = false; |
| IsMipsN64ABI = false; |
| return; |
| } |
| unsigned AbiVariant; |
| Obj.getPlatformFlags(AbiVariant); |
| IsMipsO32ABI = AbiVariant & ELF::EF_MIPS_ABI_O32; |
| IsMipsN32ABI = AbiVariant & ELF::EF_MIPS_ABI2; |
| IsMipsN64ABI = Obj.getFileFormatName().equals("ELF64-mips"); |
| } |
| |
| // Return the .TOC. section and offset. |
| Error RuntimeDyldELF::findPPC64TOCSection(const ELFObjectFileBase &Obj, |
| ObjSectionToIDMap &LocalSections, |
| RelocationValueRef &Rel) { |
| // Set a default SectionID in case we do not find a TOC section below. |
| // This may happen for references to TOC base base (sym@toc, .odp |
| // relocation) without a .toc directive. In this case just use the |
| // first section (which is usually the .odp) since the code won't |
| // reference the .toc base directly. |
| Rel.SymbolName = nullptr; |
| Rel.SectionID = 0; |
| |
| // The TOC consists of sections .got, .toc, .tocbss, .plt in that |
| // order. The TOC starts where the first of these sections starts. |
| for (auto &Section: Obj.sections()) { |
| StringRef SectionName; |
| if (auto EC = Section.getName(SectionName)) |
| return errorCodeToError(EC); |
| |
| if (SectionName == ".got" |
| || SectionName == ".toc" |
| || SectionName == ".tocbss" |
| || SectionName == ".plt") { |
| if (auto SectionIDOrErr = |
| findOrEmitSection(Obj, Section, false, LocalSections)) |
| Rel.SectionID = *SectionIDOrErr; |
| else |
| return SectionIDOrErr.takeError(); |
| break; |
| } |
| } |
| |
| // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000 |
| // thus permitting a full 64 Kbytes segment. |
| Rel.Addend = 0x8000; |
| |
| return Error::success(); |
| } |
| |
| // Returns the sections and offset associated with the ODP entry referenced |
| // by Symbol. |
| Error RuntimeDyldELF::findOPDEntrySection(const ELFObjectFileBase &Obj, |
| ObjSectionToIDMap &LocalSections, |
| RelocationValueRef &Rel) { |
| // Get the ELF symbol value (st_value) to compare with Relocation offset in |
| // .opd entries |
| for (section_iterator si = Obj.section_begin(), se = Obj.section_end(); |
| si != se; ++si) { |
| section_iterator RelSecI = si->getRelocatedSection(); |
| if (RelSecI == Obj.section_end()) |
| continue; |
| |
| StringRef RelSectionName; |
| if (auto EC = RelSecI->getName(RelSectionName)) |
| return errorCodeToError(EC); |
| |
| if (RelSectionName != ".opd") |
| continue; |
| |
| for (elf_relocation_iterator i = si->relocation_begin(), |
| e = si->relocation_end(); |
| i != e;) { |
| // The R_PPC64_ADDR64 relocation indicates the first field |
| // of a .opd entry |
| uint64_t TypeFunc = i->getType(); |
| if (TypeFunc != ELF::R_PPC64_ADDR64) { |
| ++i; |
| continue; |
| } |
| |
| uint64_t TargetSymbolOffset = i->getOffset(); |
| symbol_iterator TargetSymbol = i->getSymbol(); |
| int64_t Addend; |
| if (auto AddendOrErr = i->getAddend()) |
| Addend = *AddendOrErr; |
| else |
| return errorCodeToError(AddendOrErr.getError()); |
| |
| ++i; |
| if (i == e) |
| break; |
| |
| // Just check if following relocation is a R_PPC64_TOC |
| uint64_t TypeTOC = i->getType(); |
| if (TypeTOC != ELF::R_PPC64_TOC) |
| continue; |
| |
| // Finally compares the Symbol value and the target symbol offset |
| // to check if this .opd entry refers to the symbol the relocation |
| // points to. |
| if (Rel.Addend != (int64_t)TargetSymbolOffset) |
| continue; |
| |
| section_iterator TSI = Obj.section_end(); |
| if (auto TSIOrErr = TargetSymbol->getSection()) |
| TSI = *TSIOrErr; |
| else |
| return TSIOrErr.takeError(); |
| assert(TSI != Obj.section_end() && "TSI should refer to a valid section"); |
| |
| bool IsCode = TSI->isText(); |
| if (auto SectionIDOrErr = findOrEmitSection(Obj, *TSI, IsCode, |
| LocalSections)) |
| Rel.SectionID = *SectionIDOrErr; |
| else |
| return SectionIDOrErr.takeError(); |
| Rel.Addend = (intptr_t)Addend; |
| return Error::success(); |
| } |
| } |
| llvm_unreachable("Attempting to get address of ODP entry!"); |
| } |
| |
| // Relocation masks following the #lo(value), #hi(value), #ha(value), |
| // #higher(value), #highera(value), #highest(value), and #highesta(value) |
| // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi |
| // document. |
| |
| static inline uint16_t applyPPClo(uint64_t value) { return value & 0xffff; } |
| |
| static inline uint16_t applyPPChi(uint64_t value) { |
| return (value >> 16) & 0xffff; |
| } |
| |
| static inline uint16_t applyPPCha (uint64_t value) { |
| return ((value + 0x8000) >> 16) & 0xffff; |
| } |
| |
| static inline uint16_t applyPPChigher(uint64_t value) { |
| return (value >> 32) & 0xffff; |
| } |
| |
| static inline uint16_t applyPPChighera (uint64_t value) { |
| return ((value + 0x8000) >> 32) & 0xffff; |
| } |
| |
| static inline uint16_t applyPPChighest(uint64_t value) { |
| return (value >> 48) & 0xffff; |
| } |
| |
| static inline uint16_t applyPPChighesta (uint64_t value) { |
| return ((value + 0x8000) >> 48) & 0xffff; |
| } |
| |
| void RuntimeDyldELF::resolvePPC32Relocation(const SectionEntry &Section, |
| uint64_t Offset, uint64_t Value, |
| uint32_t Type, int64_t Addend) { |
| uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); |
| switch (Type) { |
| default: |
| llvm_unreachable("Relocation type not implemented yet!"); |
| break; |
| case ELF::R_PPC_ADDR16_LO: |
| writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); |
| break; |
| case ELF::R_PPC_ADDR16_HI: |
| writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); |
| break; |
| case ELF::R_PPC_ADDR16_HA: |
| writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); |
| break; |
| } |
| } |
| |
| void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section, |
| uint64_t Offset, uint64_t Value, |
| uint32_t Type, int64_t Addend) { |
| uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); |
| switch (Type) { |
| default: |
| llvm_unreachable("Relocation type not implemented yet!"); |
| break; |
| case ELF::R_PPC64_ADDR16: |
| writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); |
| break; |
| case ELF::R_PPC64_ADDR16_DS: |
| writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); |
| break; |
| case ELF::R_PPC64_ADDR16_LO: |
| writeInt16BE(LocalAddress, applyPPClo(Value + Addend)); |
| break; |
| case ELF::R_PPC64_ADDR16_LO_DS: |
| writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3); |
| break; |
| case ELF::R_PPC64_ADDR16_HI: |
| writeInt16BE(LocalAddress, applyPPChi(Value + Addend)); |
| break; |
| case ELF::R_PPC64_ADDR16_HA: |
| writeInt16BE(LocalAddress, applyPPCha(Value + Addend)); |
| break; |
| case ELF::R_PPC64_ADDR16_HIGHER: |
| writeInt16BE(LocalAddress, applyPPChigher(Value + Addend)); |
| break; |
| case ELF::R_PPC64_ADDR16_HIGHERA: |
| writeInt16BE(LocalAddress, applyPPChighera(Value + Addend)); |
| break; |
| case ELF::R_PPC64_ADDR16_HIGHEST: |
| writeInt16BE(LocalAddress, applyPPChighest(Value + Addend)); |
| break; |
| case ELF::R_PPC64_ADDR16_HIGHESTA: |
| writeInt16BE(LocalAddress, applyPPChighesta(Value + Addend)); |
| break; |
| case ELF::R_PPC64_ADDR14: { |
| assert(((Value + Addend) & 3) == 0); |
| // Preserve the AA/LK bits in the branch instruction |
| uint8_t aalk = *(LocalAddress + 3); |
| writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc)); |
| } break; |
| case ELF::R_PPC64_REL16_LO: { |
| uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); |
| uint64_t Delta = Value - FinalAddress + Addend; |
| writeInt16BE(LocalAddress, applyPPClo(Delta)); |
| } break; |
| case ELF::R_PPC64_REL16_HI: { |
| uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); |
| uint64_t Delta = Value - FinalAddress + Addend; |
| writeInt16BE(LocalAddress, applyPPChi(Delta)); |
| } break; |
| case ELF::R_PPC64_REL16_HA: { |
| uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); |
| uint64_t Delta = Value - FinalAddress + Addend; |
| writeInt16BE(LocalAddress, applyPPCha(Delta)); |
| } break; |
| case ELF::R_PPC64_ADDR32: { |
| int64_t Result = static_cast<int64_t>(Value + Addend); |
| if (SignExtend64<32>(Result) != Result) |
| llvm_unreachable("Relocation R_PPC64_ADDR32 overflow"); |
| writeInt32BE(LocalAddress, Result); |
| } break; |
| case ELF::R_PPC64_REL24: { |
| uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); |
| int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend); |
| if (SignExtend64<26>(delta) != delta) |
| llvm_unreachable("Relocation R_PPC64_REL24 overflow"); |
| // Generates a 'bl <address>' instruction |
| writeInt32BE(LocalAddress, 0x48000001 | (delta & 0x03FFFFFC)); |
| } break; |
| case ELF::R_PPC64_REL32: { |
| uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); |
| int64_t delta = static_cast<int64_t>(Value - FinalAddress + Addend); |
| if (SignExtend64<32>(delta) != delta) |
| llvm_unreachable("Relocation R_PPC64_REL32 overflow"); |
| writeInt32BE(LocalAddress, delta); |
| } break; |
| case ELF::R_PPC64_REL64: { |
| uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset); |
| uint64_t Delta = Value - FinalAddress + Addend; |
| writeInt64BE(LocalAddress, Delta); |
| } break; |
| case ELF::R_PPC64_ADDR64: |
| writeInt64BE(LocalAddress, Value + Addend); |
| break; |
| } |
| } |
| |
| void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section, |
| uint64_t Offset, uint64_t Value, |
| uint32_t Type, int64_t Addend) { |
| uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); |
| switch (Type) { |
| default: |
| llvm_unreachable("Relocation type not implemented yet!"); |
| break; |
| case ELF::R_390_PC16DBL: |
| case ELF::R_390_PLT16DBL: { |
| int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); |
| assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow"); |
| writeInt16BE(LocalAddress, Delta / 2); |
| break; |
| } |
| case ELF::R_390_PC32DBL: |
| case ELF::R_390_PLT32DBL: { |
| int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); |
| assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow"); |
| writeInt32BE(LocalAddress, Delta / 2); |
| break; |
| } |
| case ELF::R_390_PC16: { |
| int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); |
| assert(int16_t(Delta) == Delta && "R_390_PC16 overflow"); |
| writeInt16BE(LocalAddress, Delta); |
| break; |
| } |
| case ELF::R_390_PC32: { |
| int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); |
| assert(int32_t(Delta) == Delta && "R_390_PC32 overflow"); |
| writeInt32BE(LocalAddress, Delta); |
| break; |
| } |
| case ELF::R_390_PC64: { |
| int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset); |
| writeInt64BE(LocalAddress, Delta); |
| break; |
| } |
| case ELF::R_390_8: |
| *LocalAddress = (uint8_t)(Value + Addend); |
| break; |
| case ELF::R_390_16: |
| writeInt16BE(LocalAddress, Value + Addend); |
| break; |
| case ELF::R_390_32: |
| writeInt32BE(LocalAddress, Value + Addend); |
| break; |
| case ELF::R_390_64: |
| writeInt64BE(LocalAddress, Value + Addend); |
| break; |
| } |
| } |
| |
| void RuntimeDyldELF::resolveBPFRelocation(const SectionEntry &Section, |
| uint64_t Offset, uint64_t Value, |
| uint32_t Type, int64_t Addend) { |
| bool isBE = Arch == Triple::bpfeb; |
| |
| switch (Type) { |
| default: |
| llvm_unreachable("Relocation type not implemented yet!"); |
| break; |
| case ELF::R_BPF_NONE: |
| break; |
| case ELF::R_BPF_64_64: { |
| write(isBE, Section.getAddressWithOffset(Offset), Value + Addend); |
| DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at " |
| << format("%p\n", Section.getAddressWithOffset(Offset))); |
| break; |
| } |
| case ELF::R_BPF_64_32: { |
| Value += Addend; |
| assert(Value <= UINT32_MAX); |
| write(isBE, Section.getAddressWithOffset(Offset), static_cast<uint32_t>(Value)); |
| DEBUG(dbgs() << "Writing " << format("%p", Value) << " at " |
| << format("%p\n", Section.getAddressWithOffset(Offset))); |
| break; |
| } |
| } |
| } |
| |
| // The target location for the relocation is described by RE.SectionID and |
| // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each |
| // SectionEntry has three members describing its location. |
| // SectionEntry::Address is the address at which the section has been loaded |
| // into memory in the current (host) process. SectionEntry::LoadAddress is the |
| // address that the section will have in the target process. |
| // SectionEntry::ObjAddress is the address of the bits for this section in the |
| // original emitted object image (also in the current address space). |
| // |
| // Relocations will be applied as if the section were loaded at |
| // SectionEntry::LoadAddress, but they will be applied at an address based |
| // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to |
| // Target memory contents if they are required for value calculations. |
| // |
| // The Value parameter here is the load address of the symbol for the |
| // relocation to be applied. For relocations which refer to symbols in the |
| // current object Value will be the LoadAddress of the section in which |
| // the symbol resides (RE.Addend provides additional information about the |
| // symbol location). For external symbols, Value will be the address of the |
| // symbol in the target address space. |
| void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE, |
| uint64_t Value) { |
| const SectionEntry &Section = Sections[RE.SectionID]; |
| return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend, |
| RE.SymOffset, RE.SectionID); |
| } |
| |
| void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section, |
| uint64_t Offset, uint64_t Value, |
| uint32_t Type, int64_t Addend, |
| uint64_t SymOffset, SID SectionID) { |
| switch (Arch) { |
| case Triple::x86_64: |
| resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset); |
| break; |
| case Triple::x86: |
| resolveX86Relocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, |
| (uint32_t)(Addend & 0xffffffffL)); |
| break; |
| case Triple::aarch64: |
| case Triple::aarch64_be: |
| resolveAArch64Relocation(Section, Offset, Value, Type, Addend); |
| break; |
| case Triple::arm: // Fall through. |
| case Triple::armeb: |
| case Triple::thumb: |
| case Triple::thumbeb: |
| resolveARMRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type, |
| (uint32_t)(Addend & 0xffffffffL)); |
| break; |
| case Triple::ppc: |
| resolvePPC32Relocation(Section, Offset, Value, Type, Addend); |
| break; |
| case Triple::ppc64: // Fall through. |
| case Triple::ppc64le: |
| resolvePPC64Relocation(Section, Offset, Value, Type, Addend); |
| break; |
| case Triple::systemz: |
| resolveSystemZRelocation(Section, Offset, Value, Type, Addend); |
| break; |
| case Triple::bpfel: |
| case Triple::bpfeb: |
| resolveBPFRelocation(Section, Offset, Value, Type, Addend); |
| break; |
| default: |
| llvm_unreachable("Unsupported CPU type!"); |
| } |
| } |
| |
| void *RuntimeDyldELF::computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const { |
| return (void *)(Sections[SectionID].getObjAddress() + Offset); |
| } |
| |
| void RuntimeDyldELF::processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value) { |
| RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset); |
| if (Value.SymbolName) |
| addRelocationForSymbol(RE, Value.SymbolName); |
| else |
| addRelocationForSection(RE, Value.SectionID); |
| } |
| |
| uint32_t RuntimeDyldELF::getMatchingLoRelocation(uint32_t RelType, |
| bool IsLocal) const { |
| switch (RelType) { |
| case ELF::R_MICROMIPS_GOT16: |
| if (IsLocal) |
| return ELF::R_MICROMIPS_LO16; |
| break; |
| case ELF::R_MICROMIPS_HI16: |
| return ELF::R_MICROMIPS_LO16; |
| case ELF::R_MIPS_GOT16: |
| if (IsLocal) |
| return ELF::R_MIPS_LO16; |
| break; |
| case ELF::R_MIPS_HI16: |
| return ELF::R_MIPS_LO16; |
| case ELF::R_MIPS_PCHI16: |
| return ELF::R_MIPS_PCLO16; |
| default: |
| break; |
| } |
| return ELF::R_MIPS_NONE; |
| } |
| |
| // Sometimes we don't need to create thunk for a branch. |
| // This typically happens when branch target is located |
| // in the same object file. In such case target is either |
| // a weak symbol or symbol in a different executable section. |
| // This function checks if branch target is located in the |
| // same object file and if distance between source and target |
| // fits R_AARCH64_CALL26 relocation. If both conditions are |
| // met, it emits direct jump to the target and returns true. |
| // Otherwise false is returned and thunk is created. |
| bool RuntimeDyldELF::resolveAArch64ShortBranch( |
| unsigned SectionID, relocation_iterator RelI, |
| const RelocationValueRef &Value) { |
| uint64_t Address; |
| if (Value.SymbolName) { |
| auto Loc = GlobalSymbolTable.find(Value.SymbolName); |
| |
| // Don't create direct branch for external symbols. |
| if (Loc == GlobalSymbolTable.end()) |
| return false; |
| |
| const auto &SymInfo = Loc->second; |
| Address = |
| uint64_t(Sections[SymInfo.getSectionID()].getLoadAddressWithOffset( |
| SymInfo.getOffset())); |
| } else { |
| Address = uint64_t(Sections[Value.SectionID].getLoadAddress()); |
| } |
| uint64_t Offset = RelI->getOffset(); |
| uint64_t SourceAddress = Sections[SectionID].getLoadAddressWithOffset(Offset); |
| |
| // R_AARCH64_CALL26 requires immediate to be in range -2^27 <= imm < 2^27 |
| // If distance between source and target is out of range then we should |
| // create thunk. |
| if (!isInt<28>(Address + Value.Addend - SourceAddress)) |
| return false; |
| |
| resolveRelocation(Sections[SectionID], Offset, Address, RelI->getType(), |
| Value.Addend); |
| |
| return true; |
| } |
| |
| void RuntimeDyldELF::resolveAArch64Branch(unsigned SectionID, |
| const RelocationValueRef &Value, |
| relocation_iterator RelI, |
| StubMap &Stubs) { |
| |
| DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation."); |
| SectionEntry &Section = Sections[SectionID]; |
| |
| uint64_t Offset = RelI->getOffset(); |
| unsigned RelType = RelI->getType(); |
| // Look for an existing stub. |
| StubMap::const_iterator i = Stubs.find(Value); |
| if (i != Stubs.end()) { |
| resolveRelocation(Section, Offset, |
| (uint64_t)Section.getAddressWithOffset(i->second), |
| RelType, 0); |
| DEBUG(dbgs() << " Stub function found\n"); |
| } else if (!resolveAArch64ShortBranch(SectionID, RelI, Value)) { |
| // Create a new stub function. |
| DEBUG(dbgs() << " Create a new stub function\n"); |
| Stubs[Value] = Section.getStubOffset(); |
| uint8_t *StubTargetAddr = createStubFunction( |
| Section.getAddressWithOffset(Section.getStubOffset())); |
| |
| RelocationEntry REmovz_g3(SectionID, StubTargetAddr - Section.getAddress(), |
| ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend); |
| RelocationEntry REmovk_g2(SectionID, |
| StubTargetAddr - Section.getAddress() + 4, |
| ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend); |
| RelocationEntry REmovk_g1(SectionID, |
| StubTargetAddr - Section.getAddress() + 8, |
| ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend); |
| RelocationEntry REmovk_g0(SectionID, |
| StubTargetAddr - Section.getAddress() + 12, |
| ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend); |
| |
| if (Value.SymbolName) { |
| addRelocationForSymbol(REmovz_g3, Value.SymbolName); |
| addRelocationForSymbol(REmovk_g2, Value.SymbolName); |
| addRelocationForSymbol(REmovk_g1, Value.SymbolName); |
| addRelocationForSymbol(REmovk_g0, Value.SymbolName); |
| } else { |
| addRelocationForSection(REmovz_g3, Value.SectionID); |
| addRelocationForSection(REmovk_g2, Value.SectionID); |
| addRelocationForSection(REmovk_g1, Value.SectionID); |
| addRelocationForSection(REmovk_g0, Value.SectionID); |
| } |
| resolveRelocation(Section, Offset, |
| reinterpret_cast<uint64_t>(Section.getAddressWithOffset( |
| Section.getStubOffset())), |
| RelType, 0); |
| Section.advanceStubOffset(getMaxStubSize()); |
| } |
| } |
| |
| Expected<relocation_iterator> |
| RuntimeDyldELF::processRelocationRef( |
| unsigned SectionID, relocation_iterator RelI, const ObjectFile &O, |
| ObjSectionToIDMap &ObjSectionToID, StubMap &Stubs) { |
| const auto &Obj = cast<ELFObjectFileBase>(O); |
| uint64_t RelType = RelI->getType(); |
| ErrorOr<int64_t> AddendOrErr = ELFRelocationRef(*RelI).getAddend(); |
| int64_t Addend = AddendOrErr ? *AddendOrErr : 0; |
| elf_symbol_iterator Symbol = RelI->getSymbol(); |
| |
| // Obtain the symbol name which is referenced in the relocation |
| StringRef TargetName; |
| if (Symbol != Obj.symbol_end()) { |
| if (auto TargetNameOrErr = Symbol->getName()) |
| TargetName = *TargetNameOrErr; |
| else |
| return TargetNameOrErr.takeError(); |
| } |
| DEBUG(dbgs() << "\t\tRelType: " << RelType << " Addend: " << Addend |
| << " TargetName: " << TargetName << "\n"); |
| RelocationValueRef Value; |
| // First search for the symbol in the local symbol table |
| SymbolRef::Type SymType = SymbolRef::ST_Unknown; |
| |
| // Search for the symbol in the global symbol table |
| RTDyldSymbolTable::const_iterator gsi = GlobalSymbolTable.end(); |
| if (Symbol != Obj.symbol_end()) { |
| gsi = GlobalSymbolTable.find(TargetName.data()); |
| Expected<SymbolRef::Type> SymTypeOrErr = Symbol->getType(); |
| if (!SymTypeOrErr) { |
| std::string Buf; |
| raw_string_ostream OS(Buf); |
| logAllUnhandledErrors(SymTypeOrErr.takeError(), OS, ""); |
| OS.flush(); |
| report_fatal_error(Buf); |
| } |
| SymType = *SymTypeOrErr; |
| } |
| if (gsi != GlobalSymbolTable.end()) { |
| const auto &SymInfo = gsi->second; |
| Value.SectionID = SymInfo.getSectionID(); |
| Value.Offset = SymInfo.getOffset(); |
| Value.Addend = SymInfo.getOffset() + Addend; |
| } else { |
| switch (SymType) { |
| case SymbolRef::ST_Debug: { |
| // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously |
| // and can be changed by another developers. Maybe best way is add |
| // a new symbol type ST_Section to SymbolRef and use it. |
| auto SectionOrErr = Symbol->getSection(); |
| if (!SectionOrErr) { |
| std::string Buf; |
| raw_string_ostream OS(Buf); |
| logAllUnhandledErrors(SectionOrErr.takeError(), OS, ""); |
| OS.flush(); |
| report_fatal_error(Buf); |
| } |
| section_iterator si = *SectionOrErr; |
| if (si == Obj.section_end()) |
| llvm_unreachable("Symbol section not found, bad object file format!"); |
| DEBUG(dbgs() << "\t\tThis is section symbol\n"); |
| bool isCode = si->isText(); |
| if (auto SectionIDOrErr = findOrEmitSection(Obj, (*si), isCode, |
| ObjSectionToID)) |
| Value.SectionID = *SectionIDOrErr; |
| else |
| return SectionIDOrErr.takeError(); |
| Value.Addend = Addend; |
| break; |
| } |
| case SymbolRef::ST_Data: |
| case SymbolRef::ST_Function: |
| case SymbolRef::ST_Unknown: { |
| Value.SymbolName = TargetName.data(); |
| Value.Addend = Addend; |
| |
| // Absolute relocations will have a zero symbol ID (STN_UNDEF), which |
| // will manifest here as a NULL symbol name. |
| // We can set this as a valid (but empty) symbol name, and rely |
| // on addRelocationForSymbol to handle this. |
| if (!Value.SymbolName) |
| Value.SymbolName = ""; |
| break; |
| } |
| default: |
| llvm_unreachable("Unresolved symbol type!"); |
| break; |
| } |
| } |
| |
| uint64_t Offset = RelI->getOffset(); |
| |
| DEBUG(dbgs() << "\t\tSectionID: " << SectionID << " Offset: " << Offset |
| << "\n"); |
| if ((Arch == Triple::aarch64 || Arch == Triple::aarch64_be)) { |
| if (RelType == ELF::R_AARCH64_CALL26 || RelType == ELF::R_AARCH64_JUMP26) { |
| resolveAArch64Branch(SectionID, Value, RelI, Stubs); |
| } else if (RelType == ELF::R_AARCH64_ADR_GOT_PAGE) { |
| // Craete new GOT entry or find existing one. If GOT entry is |
| // to be created, then we also emit ABS64 relocation for it. |
| uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64); |
| resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, |
| ELF::R_AARCH64_ADR_PREL_PG_HI21); |
| |
| } else if (RelType == ELF::R_AARCH64_LD64_GOT_LO12_NC) { |
| uint64_t GOTOffset = findOrAllocGOTEntry(Value, ELF::R_AARCH64_ABS64); |
| resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, |
| ELF::R_AARCH64_LDST64_ABS_LO12_NC); |
| } else { |
| processSimpleRelocation(SectionID, Offset, RelType, Value); |
| } |
| } else if (Arch == Triple::arm) { |
| if (RelType == ELF::R_ARM_PC24 || RelType == ELF::R_ARM_CALL || |
| RelType == ELF::R_ARM_JUMP24) { |
| // This is an ARM branch relocation, need to use a stub function. |
| DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.\n"); |
| SectionEntry &Section = Sections[SectionID]; |
| |
| // Look for an existing stub. |
| StubMap::const_iterator i = Stubs.find(Value); |
| if (i != Stubs.end()) { |
| resolveRelocation( |
| Section, Offset, |
| reinterpret_cast<uint64_t>(Section.getAddressWithOffset(i->second)), |
| RelType, 0); |
| DEBUG(dbgs() << " Stub function found\n"); |
| } else { |
| // Create a new stub function. |
| DEBUG(dbgs() << " Create a new stub function\n"); |
| Stubs[Value] = Section.getStubOffset(); |
| uint8_t *StubTargetAddr = createStubFunction( |
| Section.getAddressWithOffset(Section.getStubOffset())); |
| RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), |
| ELF::R_ARM_ABS32, Value.Addend); |
| if (Value.SymbolName) |
| addRelocationForSymbol(RE, Value.SymbolName); |
| else |
| addRelocationForSection(RE, Value.SectionID); |
| |
| resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>( |
| Section.getAddressWithOffset( |
| Section.getStubOffset())), |
| RelType, 0); |
| Section.advanceStubOffset(getMaxStubSize()); |
| } |
| } else { |
| uint32_t *Placeholder = |
| reinterpret_cast<uint32_t*>(computePlaceholderAddress(SectionID, Offset)); |
| if (RelType == ELF::R_ARM_PREL31 || RelType == ELF::R_ARM_TARGET1 || |
| RelType == ELF::R_ARM_ABS32) { |
| Value.Addend += *Placeholder; |
| } else if (RelType == ELF::R_ARM_MOVW_ABS_NC || RelType == ELF::R_ARM_MOVT_ABS) { |
| // See ELF for ARM documentation |
| Value.Addend += (int16_t)((*Placeholder & 0xFFF) | (((*Placeholder >> 16) & 0xF) << 12)); |
| } |
| processSimpleRelocation(SectionID, Offset, RelType, Value); |
| } |
| } else if (IsMipsO32ABI) { |
| uint8_t *Placeholder = reinterpret_cast<uint8_t *>( |
| computePlaceholderAddress(SectionID, Offset)); |
| uint32_t Opcode = readBytesUnaligned(Placeholder, 4); |
| if (RelType == ELF::R_MIPS_26) { |
| // This is an Mips branch relocation, need to use a stub function. |
| DEBUG(dbgs() << "\t\tThis is a Mips branch relocation."); |
| SectionEntry &Section = Sections[SectionID]; |
| |
| // Extract the addend from the instruction. |
| // We shift up by two since the Value will be down shifted again |
| // when applying the relocation. |
| uint32_t Addend = (Opcode & 0x03ffffff) << 2; |
| |
| Value.Addend += Addend; |
| |
| // Look up for existing stub. |
| StubMap::const_iterator i = Stubs.find(Value); |
| if (i != Stubs.end()) { |
| RelocationEntry RE(SectionID, Offset, RelType, i->second); |
| addRelocationForSection(RE, SectionID); |
| DEBUG(dbgs() << " Stub function found\n"); |
| } else { |
| // Create a new stub function. |
| DEBUG(dbgs() << " Create a new stub function\n"); |
| Stubs[Value] = Section.getStubOffset(); |
| |
| unsigned AbiVariant; |
| O.getPlatformFlags(AbiVariant); |
| |
| uint8_t *StubTargetAddr = createStubFunction( |
| Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant); |
| |
| // Creating Hi and Lo relocations for the filled stub instructions. |
| RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(), |
| ELF::R_MIPS_HI16, Value.Addend); |
| RelocationEntry RELo(SectionID, |
| StubTargetAddr - Section.getAddress() + 4, |
| ELF::R_MIPS_LO16, Value.Addend); |
| |
| if (Value.SymbolName) { |
| addRelocationForSymbol(REHi, Value.SymbolName); |
| addRelocationForSymbol(RELo, Value.SymbolName); |
| } |
| else { |
| addRelocationForSection(REHi, Value.SectionID); |
| addRelocationForSection(RELo, Value.SectionID); |
| } |
| |
| RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset()); |
| addRelocationForSection(RE, SectionID); |
| Section.advanceStubOffset(getMaxStubSize()); |
| } |
| } else if (RelType == ELF::R_MIPS_HI16 || RelType == ELF::R_MIPS_PCHI16) { |
| int64_t Addend = (Opcode & 0x0000ffff) << 16; |
| RelocationEntry RE(SectionID, Offset, RelType, Addend); |
| PendingRelocs.push_back(std::make_pair(Value, RE)); |
| } else if (RelType == ELF::R_MIPS_LO16 || RelType == ELF::R_MIPS_PCLO16) { |
| int64_t Addend = Value.Addend + SignExtend32<16>(Opcode & 0x0000ffff); |
| for (auto I = PendingRelocs.begin(); I != PendingRelocs.end();) { |
| const RelocationValueRef &MatchingValue = I->first; |
| RelocationEntry &Reloc = I->second; |
| if (MatchingValue == Value && |
| RelType == getMatchingLoRelocation(Reloc.RelType) && |
| SectionID == Reloc.SectionID) { |
| Reloc.Addend += Addend; |
| if (Value.SymbolName) |
| addRelocationForSymbol(Reloc, Value.SymbolName); |
| else |
| addRelocationForSection(Reloc, Value.SectionID); |
| I = PendingRelocs.erase(I); |
| } else |
| ++I; |
| } |
| RelocationEntry RE(SectionID, Offset, RelType, Addend); |
| if (Value.SymbolName) |
| addRelocationForSymbol(RE, Value.SymbolName); |
| else |
| addRelocationForSection(RE, Value.SectionID); |
| } else { |
| if (RelType == ELF::R_MIPS_32) |
| Value.Addend += Opcode; |
| else if (RelType == ELF::R_MIPS_PC16) |
| Value.Addend += SignExtend32<18>((Opcode & 0x0000ffff) << 2); |
| else if (RelType == ELF::R_MIPS_PC19_S2) |
| Value.Addend += SignExtend32<21>((Opcode & 0x0007ffff) << 2); |
| else if (RelType == ELF::R_MIPS_PC21_S2) |
| Value.Addend += SignExtend32<23>((Opcode & 0x001fffff) << 2); |
| else if (RelType == ELF::R_MIPS_PC26_S2) |
| Value.Addend += SignExtend32<28>((Opcode & 0x03ffffff) << 2); |
| processSimpleRelocation(SectionID, Offset, RelType, Value); |
| } |
| } else if (IsMipsN32ABI || IsMipsN64ABI) { |
| uint32_t r_type = RelType & 0xff; |
| RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); |
| if (r_type == ELF::R_MIPS_CALL16 || r_type == ELF::R_MIPS_GOT_PAGE |
| || r_type == ELF::R_MIPS_GOT_DISP) { |
| StringMap<uint64_t>::iterator i = GOTSymbolOffsets.find(TargetName); |
| if (i != GOTSymbolOffsets.end()) |
| RE.SymOffset = i->second; |
| else { |
| RE.SymOffset = allocateGOTEntries(1); |
| GOTSymbolOffsets[TargetName] = RE.SymOffset; |
| } |
| } |
| if (Value.SymbolName) |
| addRelocationForSymbol(RE, Value.SymbolName); |
| else |
| addRelocationForSection(RE, Value.SectionID); |
| } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) { |
| if (RelType == ELF::R_PPC64_REL24) { |
| // Determine ABI variant in use for this object. |
| unsigned AbiVariant; |
| Obj.getPlatformFlags(AbiVariant); |
| AbiVariant &= ELF::EF_PPC64_ABI; |
| // A PPC branch relocation will need a stub function if the target is |
| // an external symbol (either Value.SymbolName is set, or SymType is |
| // Symbol::ST_Unknown) or if the target address is not within the |
| // signed 24-bits branch address. |
| SectionEntry &Section = Sections[SectionID]; |
| uint8_t *Target = Section.getAddressWithOffset(Offset); |
| bool RangeOverflow = false; |
| if (!Value.SymbolName && SymType != SymbolRef::ST_Unknown) { |
| if (AbiVariant != 2) { |
| // In the ELFv1 ABI, a function call may point to the .opd entry, |
| // so the final symbol value is calculated based on the relocation |
| // values in the .opd section. |
| if (auto Err = findOPDEntrySection(Obj, ObjSectionToID, Value)) |
| return std::move(Err); |
| } else { |
| // In the ELFv2 ABI, a function symbol may provide a local entry |
| // point, which must be used for direct calls. |
| uint8_t SymOther = Symbol->getOther(); |
| Value.Addend += ELF::decodePPC64LocalEntryOffset(SymOther); |
| } |
| uint8_t *RelocTarget = |
| Sections[Value.SectionID].getAddressWithOffset(Value.Addend); |
| int64_t delta = static_cast<int64_t>(Target - RelocTarget); |
| // If it is within 26-bits branch range, just set the branch target |
| if (SignExtend64<26>(delta) == delta) { |
| RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); |
| addRelocationForSection(RE, Value.SectionID); |
| } else { |
| RangeOverflow = true; |
| } |
| } |
| if (Value.SymbolName || SymType == SymbolRef::ST_Unknown || |
| RangeOverflow) { |
| // It is an external symbol (either Value.SymbolName is set, or |
| // SymType is SymbolRef::ST_Unknown) or out of range. |
| StubMap::const_iterator i = Stubs.find(Value); |
| if (i != Stubs.end()) { |
| // Symbol function stub already created, just relocate to it |
| resolveRelocation(Section, Offset, |
| reinterpret_cast<uint64_t>( |
| Section.getAddressWithOffset(i->second)), |
| RelType, 0); |
| DEBUG(dbgs() << " Stub function found\n"); |
| } else { |
| // Create a new stub function. |
| DEBUG(dbgs() << " Create a new stub function\n"); |
| Stubs[Value] = Section.getStubOffset(); |
| uint8_t *StubTargetAddr = createStubFunction( |
| Section.getAddressWithOffset(Section.getStubOffset()), |
| AbiVariant); |
| RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(), |
| ELF::R_PPC64_ADDR64, Value.Addend); |
| |
| // Generates the 64-bits address loads as exemplified in section |
| // 4.5.1 in PPC64 ELF ABI. Note that the relocations need to |
| // apply to the low part of the instructions, so we have to update |
| // the offset according to the target endianness. |
| uint64_t StubRelocOffset = StubTargetAddr - Section.getAddress(); |
| if (!IsTargetLittleEndian) |
| StubRelocOffset += 2; |
| |
| RelocationEntry REhst(SectionID, StubRelocOffset + 0, |
| ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend); |
| RelocationEntry REhr(SectionID, StubRelocOffset + 4, |
| ELF::R_PPC64_ADDR16_HIGHER, Value.Addend); |
| RelocationEntry REh(SectionID, StubRelocOffset + 12, |
| ELF::R_PPC64_ADDR16_HI, Value.Addend); |
| RelocationEntry REl(SectionID, StubRelocOffset + 16, |
| ELF::R_PPC64_ADDR16_LO, Value.Addend); |
| |
| if (Value.SymbolName) { |
| addRelocationForSymbol(REhst, Value.SymbolName); |
| addRelocationForSymbol(REhr, Value.SymbolName); |
| addRelocationForSymbol(REh, Value.SymbolName); |
| addRelocationForSymbol(REl, Value.SymbolName); |
| } else { |
| addRelocationForSection(REhst, Value.SectionID); |
| addRelocationForSection(REhr, Value.SectionID); |
| addRelocationForSection(REh, Value.SectionID); |
| addRelocationForSection(REl, Value.SectionID); |
| } |
| |
| resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>( |
| Section.getAddressWithOffset( |
| Section.getStubOffset())), |
| RelType, 0); |
| Section.advanceStubOffset(getMaxStubSize()); |
| } |
| if (Value.SymbolName || SymType == SymbolRef::ST_Unknown) { |
| // Restore the TOC for external calls |
| if (AbiVariant == 2) |
| writeInt32BE(Target + 4, 0xE8410018); // ld r2,28(r1) |
| else |
| writeInt32BE(Target + 4, 0xE8410028); // ld r2,40(r1) |
| } |
| } |
| } else if (RelType == ELF::R_PPC64_TOC16 || |
| RelType == ELF::R_PPC64_TOC16_DS || |
| RelType == ELF::R_PPC64_TOC16_LO || |
| RelType == ELF::R_PPC64_TOC16_LO_DS || |
| RelType == ELF::R_PPC64_TOC16_HI || |
| RelType == ELF::R_PPC64_TOC16_HA) { |
| // These relocations are supposed to subtract the TOC address from |
| // the final value. This does not fit cleanly into the RuntimeDyld |
| // scheme, since there may be *two* sections involved in determining |
| // the relocation value (the section of the symbol referred to by the |
| // relocation, and the TOC section associated with the current module). |
| // |
| // Fortunately, these relocations are currently only ever generated |
| // referring to symbols that themselves reside in the TOC, which means |
| // that the two sections are actually the same. Thus they cancel out |
| // and we can immediately resolve the relocation right now. |
| switch (RelType) { |
| case ELF::R_PPC64_TOC16: RelType = ELF::R_PPC64_ADDR16; break; |
| case ELF::R_PPC64_TOC16_DS: RelType = ELF::R_PPC64_ADDR16_DS; break; |
| case ELF::R_PPC64_TOC16_LO: RelType = ELF::R_PPC64_ADDR16_LO; break; |
| case ELF::R_PPC64_TOC16_LO_DS: RelType = ELF::R_PPC64_ADDR16_LO_DS; break; |
| case ELF::R_PPC64_TOC16_HI: RelType = ELF::R_PPC64_ADDR16_HI; break; |
| case ELF::R_PPC64_TOC16_HA: RelType = ELF::R_PPC64_ADDR16_HA; break; |
| default: llvm_unreachable("Wrong relocation type."); |
| } |
| |
| RelocationValueRef TOCValue; |
| if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, TOCValue)) |
| return std::move(Err); |
| if (Value.SymbolName || Value.SectionID != TOCValue.SectionID) |
| llvm_unreachable("Unsupported TOC relocation."); |
| Value.Addend -= TOCValue.Addend; |
| resolveRelocation(Sections[SectionID], Offset, Value.Addend, RelType, 0); |
| } else { |
| // There are two ways to refer to the TOC address directly: either |
| // via a ELF::R_PPC64_TOC relocation (where both symbol and addend are |
| // ignored), or via any relocation that refers to the magic ".TOC." |
| // symbols (in which case the addend is respected). |
| if (RelType == ELF::R_PPC64_TOC) { |
| RelType = ELF::R_PPC64_ADDR64; |
| if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) |
| return std::move(Err); |
| } else if (TargetName == ".TOC.") { |
| if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value)) |
| return std::move(Err); |
| Value.Addend += Addend; |
| } |
| |
| RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); |
| |
| if (Value.SymbolName) |
| addRelocationForSymbol(RE, Value.SymbolName); |
| else |
| addRelocationForSection(RE, Value.SectionID); |
| } |
| } else if (Arch == Triple::systemz && |
| (RelType == ELF::R_390_PLT32DBL || RelType == ELF::R_390_GOTENT)) { |
| // Create function stubs for both PLT and GOT references, regardless of |
| // whether the GOT reference is to data or code. The stub contains the |
| // full address of the symbol, as needed by GOT references, and the |
| // executable part only adds an overhead of 8 bytes. |
| // |
| // We could try to conserve space by allocating the code and data |
| // parts of the stub separately. However, as things stand, we allocate |
| // a stub for every relocation, so using a GOT in JIT code should be |
| // no less space efficient than using an explicit constant pool. |
| DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation."); |
| SectionEntry &Section = Sections[SectionID]; |
| |
| // Look for an existing stub. |
| StubMap::const_iterator i = Stubs.find(Value); |
| uintptr_t StubAddress; |
| if (i != Stubs.end()) { |
| StubAddress = uintptr_t(Section.getAddressWithOffset(i->second)); |
| DEBUG(dbgs() << " Stub function found\n"); |
| } else { |
| // Create a new stub function. |
| DEBUG(dbgs() << " Create a new stub function\n"); |
| |
| uintptr_t BaseAddress = uintptr_t(Section.getAddress()); |
| uintptr_t StubAlignment = getStubAlignment(); |
| StubAddress = |
| (BaseAddress + Section.getStubOffset() + StubAlignment - 1) & |
| -StubAlignment; |
| unsigned StubOffset = StubAddress - BaseAddress; |
| |
| Stubs[Value] = StubOffset; |
| createStubFunction((uint8_t *)StubAddress); |
| RelocationEntry RE(SectionID, StubOffset + 8, ELF::R_390_64, |
| Value.Offset); |
| if (Value.SymbolName) |
| addRelocationForSymbol(RE, Value.SymbolName); |
| else |
| addRelocationForSection(RE, Value.SectionID); |
| Section.advanceStubOffset(getMaxStubSize()); |
| } |
| |
| if (RelType == ELF::R_390_GOTENT) |
| resolveRelocation(Section, Offset, StubAddress + 8, ELF::R_390_PC32DBL, |
| Addend); |
| else |
| resolveRelocation(Section, Offset, StubAddress, RelType, Addend); |
| } else if (Arch == Triple::x86_64) { |
| if (RelType == ELF::R_X86_64_PLT32) { |
| // The way the PLT relocations normally work is that the linker allocates |
| // the |
| // PLT and this relocation makes a PC-relative call into the PLT. The PLT |
| // entry will then jump to an address provided by the GOT. On first call, |
| // the |
| // GOT address will point back into PLT code that resolves the symbol. After |
| // the first call, the GOT entry points to the actual function. |
| // |
| // For local functions we're ignoring all of that here and just replacing |
| // the PLT32 relocation type with PC32, which will translate the relocation |
| // into a PC-relative call directly to the function. For external symbols we |
| // can't be sure the function will be within 2^32 bytes of the call site, so |
| // we need to create a stub, which calls into the GOT. This case is |
| // equivalent to the usual PLT implementation except that we use the stub |
| // mechanism in RuntimeDyld (which puts stubs at the end of the section) |
| // rather than allocating a PLT section. |
| if (Value.SymbolName) { |
| // This is a call to an external function. |
| // Look for an existing stub. |
| SectionEntry &Section = Sections[SectionID]; |
| StubMap::const_iterator i = Stubs.find(Value); |
| uintptr_t StubAddress; |
| if (i != Stubs.end()) { |
| StubAddress = uintptr_t(Section.getAddress()) + i->second; |
| DEBUG(dbgs() << " Stub function found\n"); |
| } else { |
| // Create a new stub function (equivalent to a PLT entry). |
| DEBUG(dbgs() << " Create a new stub function\n"); |
| |
| uintptr_t BaseAddress = uintptr_t(Section.getAddress()); |
| uintptr_t StubAlignment = getStubAlignment(); |
| StubAddress = |
| (BaseAddress + Section.getStubOffset() + StubAlignment - 1) & |
| -StubAlignment; |
| unsigned StubOffset = StubAddress - BaseAddress; |
| Stubs[Value] = StubOffset; |
| createStubFunction((uint8_t *)StubAddress); |
| |
| // Bump our stub offset counter |
| Section.advanceStubOffset(getMaxStubSize()); |
| |
| // Allocate a GOT Entry |
| uint64_t GOTOffset = allocateGOTEntries(1); |
| |
| // The load of the GOT address has an addend of -4 |
| resolveGOTOffsetRelocation(SectionID, StubOffset + 2, GOTOffset - 4, |
| ELF::R_X86_64_PC32); |
| |
| // Fill in the value of the symbol we're targeting into the GOT |
| addRelocationForSymbol( |
| computeGOTOffsetRE(GOTOffset, 0, ELF::R_X86_64_64), |
| Value.SymbolName); |
| } |
| |
| // Make the target call a call into the stub table. |
| resolveRelocation(Section, Offset, StubAddress, ELF::R_X86_64_PC32, |
| Addend); |
| } else { |
| RelocationEntry RE(SectionID, Offset, ELF::R_X86_64_PC32, Value.Addend, |
| Value.Offset); |
| addRelocationForSection(RE, Value.SectionID); |
| } |
| } else if (RelType == ELF::R_X86_64_GOTPCREL || |
| RelType == ELF::R_X86_64_GOTPCRELX || |
| RelType == ELF::R_X86_64_REX_GOTPCRELX) { |
| uint64_t GOTOffset = allocateGOTEntries(1); |
| resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend, |
| ELF::R_X86_64_PC32); |
| |
| // Fill in the value of the symbol we're targeting into the GOT |
| RelocationEntry RE = |
| computeGOTOffsetRE(GOTOffset, Value.Offset, ELF::R_X86_64_64); |
| if (Value.SymbolName) |
| addRelocationForSymbol(RE, Value.SymbolName); |
| else |
| addRelocationForSection(RE, Value.SectionID); |
| } else if (RelType == ELF::R_X86_64_PC32) { |
| Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); |
| processSimpleRelocation(SectionID, Offset, RelType, Value); |
| } else if (RelType == ELF::R_X86_64_PC64) { |
| Value.Addend += support::ulittle64_t::ref(computePlaceholderAddress(SectionID, Offset)); |
| processSimpleRelocation(SectionID, Offset, RelType, Value); |
| } else { |
| processSimpleRelocation(SectionID, Offset, RelType, Value); |
| } |
| } else { |
| if (Arch == Triple::x86) { |
| Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset)); |
| } |
| processSimpleRelocation(SectionID, Offset, RelType, Value); |
| } |
| return ++RelI; |
| } |
| |
| size_t RuntimeDyldELF::getGOTEntrySize() { |
| // We don't use the GOT in all of these cases, but it's essentially free |
| // to put them all here. |
| size_t Result = 0; |
| switch (Arch) { |
| case Triple::x86_64: |
| case Triple::aarch64: |
| case Triple::aarch64_be: |
| case Triple::ppc64: |
| case Triple::ppc64le: |
| case Triple::systemz: |
| Result = sizeof(uint64_t); |
| break; |
| case Triple::x86: |
| case Triple::arm: |
| case Triple::thumb: |
| Result = sizeof(uint32_t); |
| break; |
| case Triple::mips: |
| case Triple::mipsel: |
| case Triple::mips64: |
| case Triple::mips64el: |
| if (IsMipsO32ABI || IsMipsN32ABI) |
| Result = sizeof(uint32_t); |
| else if (IsMipsN64ABI) |
| Result = sizeof(uint64_t); |
| else |
| llvm_unreachable("Mips ABI not handled"); |
| break; |
| default: |
| llvm_unreachable("Unsupported CPU type!"); |
| } |
| return Result; |
| } |
| |
| uint64_t RuntimeDyldELF::allocateGOTEntries(unsigned no) { |
| if (GOTSectionID == 0) { |
| GOTSectionID = Sections.size(); |
| // Reserve a section id. We'll allocate the section later |
| // once we know the total size |
| Sections.push_back(SectionEntry(".got", nullptr, 0, 0, 0)); |
| } |
| uint64_t StartOffset = CurrentGOTIndex * getGOTEntrySize(); |
| CurrentGOTIndex += no; |
| return StartOffset; |
| } |
| |
| uint64_t RuntimeDyldELF::findOrAllocGOTEntry(const RelocationValueRef &Value, |
| unsigned GOTRelType) { |
| auto E = GOTOffsetMap.insert({Value, 0}); |
| if (E.second) { |
| uint64_t GOTOffset = allocateGOTEntries(1); |
| |
| // Create relocation for newly created GOT entry |
| RelocationEntry RE = |
| computeGOTOffsetRE(GOTOffset, Value.Offset, GOTRelType); |
| if (Value.SymbolName) |
| addRelocationForSymbol(RE, Value.SymbolName); |
| else |
| addRelocationForSection(RE, Value.SectionID); |
| |
| E.first->second = GOTOffset; |
| } |
| |
| return E.first->second; |
| } |
| |
| void RuntimeDyldELF::resolveGOTOffsetRelocation(unsigned SectionID, |
| uint64_t Offset, |
| uint64_t GOTOffset, |
| uint32_t Type) { |
| // Fill in the relative address of the GOT Entry into the stub |
| RelocationEntry GOTRE(SectionID, Offset, Type, GOTOffset); |
| addRelocationForSection(GOTRE, GOTSectionID); |
| } |
| |
| RelocationEntry RuntimeDyldELF::computeGOTOffsetRE(uint64_t GOTOffset, |
| uint64_t SymbolOffset, |
| uint32_t Type) { |
| return RelocationEntry(GOTSectionID, GOTOffset, Type, SymbolOffset); |
| } |
| |
| Error RuntimeDyldELF::finalizeLoad(const ObjectFile &Obj, |
| ObjSectionToIDMap &SectionMap) { |
| if (IsMipsO32ABI) |
| if (!PendingRelocs.empty()) |
| return make_error<RuntimeDyldError>("Can't find matching LO16 reloc"); |
| |
| // If necessary, allocate the global offset table |
| if (GOTSectionID != 0) { |
| // Allocate memory for the section |
| size_t TotalSize = CurrentGOTIndex * getGOTEntrySize(); |
| uint8_t *Addr = MemMgr.allocateDataSection(TotalSize, getGOTEntrySize(), |
| GOTSectionID, ".got", false); |
| if (!Addr) |
| return make_error<RuntimeDyldError>("Unable to allocate memory for GOT!"); |
| |
| Sections[GOTSectionID] = |
| SectionEntry(".got", Addr, TotalSize, TotalSize, 0); |
| |
| if (Checker) |
| Checker->registerSection(Obj.getFileName(), GOTSectionID); |
| |
| // For now, initialize all GOT entries to zero. We'll fill them in as |
| // needed when GOT-based relocations are applied. |
| memset(Addr, 0, TotalSize); |
| if (IsMipsN32ABI || IsMipsN64ABI) { |
| // To correctly resolve Mips GOT relocations, we need a mapping from |
| // object's sections to GOTs. |
| for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end(); |
| SI != SE; ++SI) { |
| if (SI->relocation_begin() != SI->relocation_end()) { |
| section_iterator RelocatedSection = SI->getRelocatedSection(); |
| ObjSectionToIDMap::iterator i = SectionMap.find(*RelocatedSection); |
| assert (i != SectionMap.end()); |
| SectionToGOTMap[i->second] = GOTSectionID; |
| } |
| } |
| GOTSymbolOffsets.clear(); |
| } |
| } |
| |
| // Look for and record the EH frame section. |
| ObjSectionToIDMap::iterator i, e; |
| for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) { |
| const SectionRef &Section = i->first; |
| StringRef Name; |
| Section.getName(Name); |
| if (Name == ".eh_frame") { |
| UnregisteredEHFrameSections.push_back(i->second); |
| break; |
| } |
| } |
| |
| GOTSectionID = 0; |
| CurrentGOTIndex = 0; |
| |
| return Error::success(); |
| } |
| |
| bool RuntimeDyldELF::isCompatibleFile(const object::ObjectFile &Obj) const { |
| return Obj.isELF(); |
| } |
| |
| bool RuntimeDyldELF::relocationNeedsGot(const RelocationRef &R) const { |
| unsigned RelTy = R.getType(); |
| if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) |
| return RelTy == ELF::R_AARCH64_ADR_GOT_PAGE || |
| RelTy == ELF::R_AARCH64_LD64_GOT_LO12_NC; |
| |
| if (Arch == Triple::x86_64) |
| return RelTy == ELF::R_X86_64_GOTPCREL || |
| RelTy == ELF::R_X86_64_GOTPCRELX || |
| RelTy == ELF::R_X86_64_REX_GOTPCRELX; |
| return false; |
| } |
| |
| bool RuntimeDyldELF::relocationNeedsStub(const RelocationRef &R) const { |
| if (Arch != Triple::x86_64) |
| return true; // Conservative answer |
| |
| switch (R.getType()) { |
| default: |
| return true; // Conservative answer |
| |
| |
| case ELF::R_X86_64_GOTPCREL: |
| case ELF::R_X86_64_GOTPCRELX: |
| case ELF::R_X86_64_REX_GOTPCRELX: |
| case ELF::R_X86_64_PC32: |
| case ELF::R_X86_64_PC64: |
| case ELF::R_X86_64_64: |
| // We know that these reloation types won't need a stub function. This list |
| // can be extended as needed. |
| return false; |
| } |
| } |
| |
| } // namespace llvm |