| //===- yaml2elf - Convert YAML to a ELF object file -----------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| /// |
| /// \file |
| /// The ELF component of yaml2obj. |
| /// |
| //===----------------------------------------------------------------------===// |
| |
| #include "yaml2obj.h" |
| #include "llvm/ADT/ArrayRef.h" |
| #include "llvm/BinaryFormat/ELF.h" |
| #include "llvm/MC/StringTableBuilder.h" |
| #include "llvm/Object/ELFObjectFile.h" |
| #include "llvm/ObjectYAML/ELFYAML.h" |
| #include "llvm/Support/MemoryBuffer.h" |
| #include "llvm/Support/WithColor.h" |
| #include "llvm/Support/YAMLTraits.h" |
| #include "llvm/Support/raw_ostream.h" |
| |
| using namespace llvm; |
| |
| // This class is used to build up a contiguous binary blob while keeping |
| // track of an offset in the output (which notionally begins at |
| // `InitialOffset`). |
| namespace { |
| class ContiguousBlobAccumulator { |
| const uint64_t InitialOffset; |
| SmallVector<char, 128> Buf; |
| raw_svector_ostream OS; |
| |
| /// \returns The new offset. |
| uint64_t padToAlignment(unsigned Align) { |
| if (Align == 0) |
| Align = 1; |
| uint64_t CurrentOffset = InitialOffset + OS.tell(); |
| uint64_t AlignedOffset = alignTo(CurrentOffset, Align); |
| for (; CurrentOffset != AlignedOffset; ++CurrentOffset) |
| OS.write('\0'); |
| return AlignedOffset; // == CurrentOffset; |
| } |
| |
| public: |
| ContiguousBlobAccumulator(uint64_t InitialOffset_) |
| : InitialOffset(InitialOffset_), Buf(), OS(Buf) {} |
| template <class Integer> |
| raw_ostream &getOSAndAlignedOffset(Integer &Offset, unsigned Align) { |
| Offset = padToAlignment(Align); |
| return OS; |
| } |
| void writeBlobToStream(raw_ostream &Out) { Out << OS.str(); } |
| }; |
| } // end anonymous namespace |
| |
| // Used to keep track of section and symbol names, so that in the YAML file |
| // sections and symbols can be referenced by name instead of by index. |
| namespace { |
| class NameToIdxMap { |
| StringMap<int> Map; |
| public: |
| /// \returns true if name is already present in the map. |
| bool addName(StringRef Name, unsigned i) { |
| return !Map.insert(std::make_pair(Name, (int)i)).second; |
| } |
| /// \returns true if name is not present in the map |
| bool lookup(StringRef Name, unsigned &Idx) const { |
| StringMap<int>::const_iterator I = Map.find(Name); |
| if (I == Map.end()) |
| return true; |
| Idx = I->getValue(); |
| return false; |
| } |
| /// asserts if name is not present in the map |
| unsigned get(StringRef Name) const { |
| unsigned Idx = 0; |
| auto missing = lookup(Name, Idx); |
| (void)missing; |
| assert(!missing && "Expected section not found in index"); |
| return Idx; |
| } |
| unsigned size() const { return Map.size(); } |
| }; |
| } // end anonymous namespace |
| |
| template <class T> |
| static size_t arrayDataSize(ArrayRef<T> A) { |
| return A.size() * sizeof(T); |
| } |
| |
| template <class T> |
| static void writeArrayData(raw_ostream &OS, ArrayRef<T> A) { |
| OS.write((const char *)A.data(), arrayDataSize(A)); |
| } |
| |
| template <class T> |
| static void zero(T &Obj) { |
| memset(&Obj, 0, sizeof(Obj)); |
| } |
| |
| namespace { |
| /// "Single point of truth" for the ELF file construction. |
| /// TODO: This class still has a ways to go before it is truly a "single |
| /// point of truth". |
| template <class ELFT> |
| class ELFState { |
| typedef typename ELFT::Ehdr Elf_Ehdr; |
| typedef typename ELFT::Phdr Elf_Phdr; |
| typedef typename ELFT::Shdr Elf_Shdr; |
| typedef typename ELFT::Sym Elf_Sym; |
| typedef typename ELFT::Rel Elf_Rel; |
| typedef typename ELFT::Rela Elf_Rela; |
| typedef typename ELFT::Relr Elf_Relr; |
| typedef typename ELFT::Dyn Elf_Dyn; |
| |
| enum class SymtabType { Static, Dynamic }; |
| |
| /// The future ".strtab" section. |
| StringTableBuilder DotStrtab{StringTableBuilder::ELF}; |
| |
| /// The future ".shstrtab" section. |
| StringTableBuilder DotShStrtab{StringTableBuilder::ELF}; |
| |
| /// The future ".dynstr" section. |
| StringTableBuilder DotDynstr{StringTableBuilder::ELF}; |
| |
| NameToIdxMap SN2I; |
| NameToIdxMap SymN2I; |
| const ELFYAML::Object &Doc; |
| |
| bool buildSectionIndex(); |
| bool buildSymbolIndex(std::size_t &StartIndex, |
| const std::vector<ELFYAML::Symbol> &Symbols); |
| void initELFHeader(Elf_Ehdr &Header); |
| void initProgramHeaders(std::vector<Elf_Phdr> &PHeaders); |
| bool initSectionHeaders(std::vector<Elf_Shdr> &SHeaders, |
| ContiguousBlobAccumulator &CBA); |
| void initSymtabSectionHeader(Elf_Shdr &SHeader, SymtabType STType, |
| ContiguousBlobAccumulator &CBA); |
| void initStrtabSectionHeader(Elf_Shdr &SHeader, StringRef Name, |
| StringTableBuilder &STB, |
| ContiguousBlobAccumulator &CBA); |
| void setProgramHeaderLayout(std::vector<Elf_Phdr> &PHeaders, |
| std::vector<Elf_Shdr> &SHeaders); |
| void addSymbols(const std::vector<ELFYAML::Symbol> &Symbols, |
| std::vector<Elf_Sym> &Syms, unsigned SymbolBinding, |
| const StringTableBuilder &Strtab); |
| void writeSectionContent(Elf_Shdr &SHeader, |
| const ELFYAML::RawContentSection &Section, |
| ContiguousBlobAccumulator &CBA); |
| bool writeSectionContent(Elf_Shdr &SHeader, |
| const ELFYAML::RelocationSection &Section, |
| ContiguousBlobAccumulator &CBA); |
| bool writeSectionContent(Elf_Shdr &SHeader, const ELFYAML::Group &Group, |
| ContiguousBlobAccumulator &CBA); |
| bool writeSectionContent(Elf_Shdr &SHeader, |
| const ELFYAML::MipsABIFlags &Section, |
| ContiguousBlobAccumulator &CBA); |
| bool hasDynamicSymbols() const; |
| SmallVector<const char *, 5> implicitSectionNames() const; |
| |
| // - SHT_NULL entry (placed first, i.e. 0'th entry) |
| // - symbol table (.symtab) (defaults to after last yaml section) |
| // - string table (.strtab) (defaults to after .symtab) |
| // - section header string table (.shstrtab) (defaults to after .strtab) |
| // - dynamic symbol table (.dynsym) (defaults to after .shstrtab) |
| // - dynamic string table (.dynstr) (defaults to after .dynsym) |
| unsigned getDotSymTabSecNo() const { return SN2I.get(".symtab"); } |
| unsigned getDotStrTabSecNo() const { return SN2I.get(".strtab"); } |
| unsigned getDotShStrTabSecNo() const { return SN2I.get(".shstrtab"); } |
| unsigned getDotDynSymSecNo() const { return SN2I.get(".dynsym"); } |
| unsigned getDotDynStrSecNo() const { return SN2I.get(".dynstr"); } |
| unsigned getSectionCount() const { return SN2I.size() + 1; } |
| |
| ELFState(const ELFYAML::Object &D) : Doc(D) {} |
| |
| public: |
| static int writeELF(raw_ostream &OS, const ELFYAML::Object &Doc); |
| }; |
| } // end anonymous namespace |
| |
| template <class ELFT> |
| void ELFState<ELFT>::initELFHeader(Elf_Ehdr &Header) { |
| using namespace llvm::ELF; |
| zero(Header); |
| Header.e_ident[EI_MAG0] = 0x7f; |
| Header.e_ident[EI_MAG1] = 'E'; |
| Header.e_ident[EI_MAG2] = 'L'; |
| Header.e_ident[EI_MAG3] = 'F'; |
| Header.e_ident[EI_CLASS] = ELFT::Is64Bits ? ELFCLASS64 : ELFCLASS32; |
| bool IsLittleEndian = ELFT::TargetEndianness == support::little; |
| Header.e_ident[EI_DATA] = IsLittleEndian ? ELFDATA2LSB : ELFDATA2MSB; |
| Header.e_ident[EI_VERSION] = EV_CURRENT; |
| Header.e_ident[EI_OSABI] = Doc.Header.OSABI; |
| Header.e_ident[EI_ABIVERSION] = 0; |
| Header.e_type = Doc.Header.Type; |
| Header.e_machine = Doc.Header.Machine; |
| Header.e_version = EV_CURRENT; |
| Header.e_entry = Doc.Header.Entry; |
| Header.e_phoff = sizeof(Header); |
| Header.e_flags = Doc.Header.Flags; |
| Header.e_ehsize = sizeof(Elf_Ehdr); |
| Header.e_phentsize = sizeof(Elf_Phdr); |
| Header.e_phnum = Doc.ProgramHeaders.size(); |
| Header.e_shentsize = sizeof(Elf_Shdr); |
| // Immediately following the ELF header and program headers. |
| Header.e_shoff = |
| sizeof(Header) + sizeof(Elf_Phdr) * Doc.ProgramHeaders.size(); |
| Header.e_shnum = getSectionCount(); |
| Header.e_shstrndx = getDotShStrTabSecNo(); |
| } |
| |
| template <class ELFT> |
| void ELFState<ELFT>::initProgramHeaders(std::vector<Elf_Phdr> &PHeaders) { |
| for (const auto &YamlPhdr : Doc.ProgramHeaders) { |
| Elf_Phdr Phdr; |
| Phdr.p_type = YamlPhdr.Type; |
| Phdr.p_flags = YamlPhdr.Flags; |
| Phdr.p_vaddr = YamlPhdr.VAddr; |
| Phdr.p_paddr = YamlPhdr.PAddr; |
| PHeaders.push_back(Phdr); |
| } |
| } |
| |
| template <class ELFT> |
| bool ELFState<ELFT>::initSectionHeaders(std::vector<Elf_Shdr> &SHeaders, |
| ContiguousBlobAccumulator &CBA) { |
| // Ensure SHN_UNDEF entry is present. An all-zero section header is a |
| // valid SHN_UNDEF entry since SHT_NULL == 0. |
| Elf_Shdr SHeader; |
| zero(SHeader); |
| SHeaders.push_back(SHeader); |
| |
| for (const auto &Sec : Doc.Sections) { |
| zero(SHeader); |
| SHeader.sh_name = DotShStrtab.getOffset(Sec->Name); |
| SHeader.sh_type = Sec->Type; |
| SHeader.sh_flags = Sec->Flags; |
| SHeader.sh_addr = Sec->Address; |
| SHeader.sh_addralign = Sec->AddressAlign; |
| |
| if (!Sec->Link.empty()) { |
| unsigned Index; |
| if (SN2I.lookup(Sec->Link, Index)) { |
| WithColor::error() << "Unknown section referenced: '" << Sec->Link |
| << "' at YAML section '" << Sec->Name << "'.\n"; |
| return false; |
| } |
| SHeader.sh_link = Index; |
| } |
| |
| if (auto S = dyn_cast<ELFYAML::RawContentSection>(Sec.get())) |
| writeSectionContent(SHeader, *S, CBA); |
| else if (auto S = dyn_cast<ELFYAML::RelocationSection>(Sec.get())) { |
| if (S->Link.empty()) |
| // For relocation section set link to .symtab by default. |
| SHeader.sh_link = getDotSymTabSecNo(); |
| |
| unsigned Index; |
| if (SN2I.lookup(S->Info, Index)) { |
| if (S->Info.getAsInteger(0, Index)) { |
| WithColor::error() << "Unknown section referenced: '" << S->Info |
| << "' at YAML section '" << S->Name << "'.\n"; |
| return false; |
| } |
| } |
| SHeader.sh_info = Index; |
| |
| if (!writeSectionContent(SHeader, *S, CBA)) |
| return false; |
| } else if (auto S = dyn_cast<ELFYAML::Group>(Sec.get())) { |
| unsigned SymIdx; |
| if (SymN2I.lookup(S->Info, SymIdx)) { |
| WithColor::error() << "Unknown symbol referenced: '" << S->Info |
| << "' at YAML section '" << S->Name << "'.\n"; |
| return false; |
| } |
| SHeader.sh_info = SymIdx; |
| if (!writeSectionContent(SHeader, *S, CBA)) |
| return false; |
| } else if (auto S = dyn_cast<ELFYAML::MipsABIFlags>(Sec.get())) { |
| if (!writeSectionContent(SHeader, *S, CBA)) |
| return false; |
| } else if (auto S = dyn_cast<ELFYAML::NoBitsSection>(Sec.get())) { |
| SHeader.sh_entsize = 0; |
| SHeader.sh_size = S->Size; |
| // SHT_NOBITS section does not have content |
| // so just to setup the section offset. |
| CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign); |
| } else |
| llvm_unreachable("Unknown section type"); |
| |
| SHeaders.push_back(SHeader); |
| } |
| return true; |
| } |
| |
| template <class ELFT> |
| void ELFState<ELFT>::initSymtabSectionHeader(Elf_Shdr &SHeader, |
| SymtabType STType, |
| ContiguousBlobAccumulator &CBA) { |
| zero(SHeader); |
| bool IsStatic = STType == SymtabType::Static; |
| SHeader.sh_name = DotShStrtab.getOffset(IsStatic ? ".symtab" : ".dynsym"); |
| SHeader.sh_type = IsStatic ? ELF::SHT_SYMTAB : ELF::SHT_DYNSYM; |
| SHeader.sh_link = IsStatic ? getDotStrTabSecNo() : getDotDynStrSecNo(); |
| const auto &Symbols = IsStatic ? Doc.Symbols : Doc.DynamicSymbols; |
| auto &Strtab = IsStatic ? DotStrtab : DotDynstr; |
| // One greater than symbol table index of the last local symbol. |
| SHeader.sh_info = Symbols.Local.size() + 1; |
| SHeader.sh_entsize = sizeof(Elf_Sym); |
| SHeader.sh_addralign = 8; |
| |
| std::vector<Elf_Sym> Syms; |
| { |
| // Ensure STN_UNDEF is present |
| Elf_Sym Sym; |
| zero(Sym); |
| Syms.push_back(Sym); |
| } |
| |
| // Add symbol names to .strtab or .dynstr. |
| for (const auto &Sym : Symbols.Local) |
| Strtab.add(Sym.Name); |
| for (const auto &Sym : Symbols.Global) |
| Strtab.add(Sym.Name); |
| for (const auto &Sym : Symbols.Weak) |
| Strtab.add(Sym.Name); |
| Strtab.finalize(); |
| |
| addSymbols(Symbols.Local, Syms, ELF::STB_LOCAL, Strtab); |
| addSymbols(Symbols.Global, Syms, ELF::STB_GLOBAL, Strtab); |
| addSymbols(Symbols.Weak, Syms, ELF::STB_WEAK, Strtab); |
| |
| writeArrayData( |
| CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign), |
| makeArrayRef(Syms)); |
| SHeader.sh_size = arrayDataSize(makeArrayRef(Syms)); |
| } |
| |
| template <class ELFT> |
| void ELFState<ELFT>::initStrtabSectionHeader(Elf_Shdr &SHeader, StringRef Name, |
| StringTableBuilder &STB, |
| ContiguousBlobAccumulator &CBA) { |
| zero(SHeader); |
| SHeader.sh_name = DotShStrtab.getOffset(Name); |
| SHeader.sh_type = ELF::SHT_STRTAB; |
| STB.write(CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign)); |
| SHeader.sh_size = STB.getSize(); |
| SHeader.sh_addralign = 1; |
| } |
| |
| template <class ELFT> |
| void ELFState<ELFT>::setProgramHeaderLayout(std::vector<Elf_Phdr> &PHeaders, |
| std::vector<Elf_Shdr> &SHeaders) { |
| uint32_t PhdrIdx = 0; |
| for (auto &YamlPhdr : Doc.ProgramHeaders) { |
| auto &PHeader = PHeaders[PhdrIdx++]; |
| |
| if (YamlPhdr.Sections.size()) |
| PHeader.p_offset = UINT32_MAX; |
| else |
| PHeader.p_offset = 0; |
| |
| // Find the minimum offset for the program header. |
| for (auto SecName : YamlPhdr.Sections) { |
| uint32_t Index = 0; |
| SN2I.lookup(SecName.Section, Index); |
| const auto &SHeader = SHeaders[Index]; |
| PHeader.p_offset = std::min(PHeader.p_offset, SHeader.sh_offset); |
| } |
| |
| // Find the maximum offset of the end of a section in order to set p_filesz. |
| PHeader.p_filesz = 0; |
| for (auto SecName : YamlPhdr.Sections) { |
| uint32_t Index = 0; |
| SN2I.lookup(SecName.Section, Index); |
| const auto &SHeader = SHeaders[Index]; |
| uint64_t EndOfSection; |
| if (SHeader.sh_type == llvm::ELF::SHT_NOBITS) |
| EndOfSection = SHeader.sh_offset; |
| else |
| EndOfSection = SHeader.sh_offset + SHeader.sh_size; |
| uint64_t EndOfSegment = PHeader.p_offset + PHeader.p_filesz; |
| EndOfSegment = std::max(EndOfSegment, EndOfSection); |
| PHeader.p_filesz = EndOfSegment - PHeader.p_offset; |
| } |
| |
| // Find the memory size by adding the size of sections at the end of the |
| // segment. These should be empty (size of zero) and NOBITS sections. |
| PHeader.p_memsz = PHeader.p_filesz; |
| for (auto SecName : YamlPhdr.Sections) { |
| uint32_t Index = 0; |
| SN2I.lookup(SecName.Section, Index); |
| const auto &SHeader = SHeaders[Index]; |
| if (SHeader.sh_offset == PHeader.p_offset + PHeader.p_filesz) |
| PHeader.p_memsz += SHeader.sh_size; |
| } |
| |
| // Set the alignment of the segment to be the same as the maximum alignment |
| // of the sections with the same offset so that by default the segment |
| // has a valid and sensible alignment. |
| if (YamlPhdr.Align) { |
| PHeader.p_align = *YamlPhdr.Align; |
| } else { |
| PHeader.p_align = 1; |
| for (auto SecName : YamlPhdr.Sections) { |
| uint32_t Index = 0; |
| SN2I.lookup(SecName.Section, Index); |
| const auto &SHeader = SHeaders[Index]; |
| if (SHeader.sh_offset == PHeader.p_offset) |
| PHeader.p_align = std::max(PHeader.p_align, SHeader.sh_addralign); |
| } |
| } |
| } |
| } |
| |
| template <class ELFT> |
| void ELFState<ELFT>::addSymbols(const std::vector<ELFYAML::Symbol> &Symbols, |
| std::vector<Elf_Sym> &Syms, |
| unsigned SymbolBinding, |
| const StringTableBuilder &Strtab) { |
| for (const auto &Sym : Symbols) { |
| Elf_Sym Symbol; |
| zero(Symbol); |
| if (!Sym.Name.empty()) |
| Symbol.st_name = Strtab.getOffset(Sym.Name); |
| Symbol.setBindingAndType(SymbolBinding, Sym.Type); |
| if (!Sym.Section.empty()) { |
| unsigned Index; |
| if (SN2I.lookup(Sym.Section, Index)) { |
| WithColor::error() << "Unknown section referenced: '" << Sym.Section |
| << "' by YAML symbol " << Sym.Name << ".\n"; |
| exit(1); |
| } |
| Symbol.st_shndx = Index; |
| } else if (Sym.Index) { |
| Symbol.st_shndx = *Sym.Index; |
| } |
| // else Symbol.st_shndex == SHN_UNDEF (== 0), since it was zero'd earlier. |
| Symbol.st_value = Sym.Value; |
| Symbol.st_other = Sym.Other; |
| Symbol.st_size = Sym.Size; |
| Syms.push_back(Symbol); |
| } |
| } |
| |
| template <class ELFT> |
| void |
| ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader, |
| const ELFYAML::RawContentSection &Section, |
| ContiguousBlobAccumulator &CBA) { |
| assert(Section.Size >= Section.Content.binary_size() && |
| "Section size and section content are inconsistent"); |
| raw_ostream &OS = |
| CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign); |
| Section.Content.writeAsBinary(OS); |
| for (auto i = Section.Content.binary_size(); i < Section.Size; ++i) |
| OS.write(0); |
| if (Section.Type == llvm::ELF::SHT_RELR) |
| SHeader.sh_entsize = sizeof(Elf_Relr); |
| else if (Section.Type == llvm::ELF::SHT_DYNAMIC) |
| SHeader.sh_entsize = sizeof(Elf_Dyn); |
| else |
| SHeader.sh_entsize = 0; |
| SHeader.sh_size = Section.Size; |
| } |
| |
| static bool isMips64EL(const ELFYAML::Object &Doc) { |
| return Doc.Header.Machine == ELFYAML::ELF_EM(llvm::ELF::EM_MIPS) && |
| Doc.Header.Class == ELFYAML::ELF_ELFCLASS(ELF::ELFCLASS64) && |
| Doc.Header.Data == ELFYAML::ELF_ELFDATA(ELF::ELFDATA2LSB); |
| } |
| |
| template <class ELFT> |
| bool |
| ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader, |
| const ELFYAML::RelocationSection &Section, |
| ContiguousBlobAccumulator &CBA) { |
| assert((Section.Type == llvm::ELF::SHT_REL || |
| Section.Type == llvm::ELF::SHT_RELA) && |
| "Section type is not SHT_REL nor SHT_RELA"); |
| |
| bool IsRela = Section.Type == llvm::ELF::SHT_RELA; |
| SHeader.sh_entsize = IsRela ? sizeof(Elf_Rela) : sizeof(Elf_Rel); |
| SHeader.sh_size = SHeader.sh_entsize * Section.Relocations.size(); |
| |
| auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign); |
| |
| for (const auto &Rel : Section.Relocations) { |
| unsigned SymIdx = 0; |
| // Some special relocation, R_ARM_v4BX for instance, does not have |
| // an external reference. So it ignores the return value of lookup() |
| // here. |
| if (Rel.Symbol) |
| SymN2I.lookup(*Rel.Symbol, SymIdx); |
| |
| if (IsRela) { |
| Elf_Rela REntry; |
| zero(REntry); |
| REntry.r_offset = Rel.Offset; |
| REntry.r_addend = Rel.Addend; |
| REntry.setSymbolAndType(SymIdx, Rel.Type, isMips64EL(Doc)); |
| OS.write((const char *)&REntry, sizeof(REntry)); |
| } else { |
| Elf_Rel REntry; |
| zero(REntry); |
| REntry.r_offset = Rel.Offset; |
| REntry.setSymbolAndType(SymIdx, Rel.Type, isMips64EL(Doc)); |
| OS.write((const char *)&REntry, sizeof(REntry)); |
| } |
| } |
| return true; |
| } |
| |
| template <class ELFT> |
| bool ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader, |
| const ELFYAML::Group &Section, |
| ContiguousBlobAccumulator &CBA) { |
| typedef typename ELFT::Word Elf_Word; |
| assert(Section.Type == llvm::ELF::SHT_GROUP && |
| "Section type is not SHT_GROUP"); |
| |
| SHeader.sh_entsize = sizeof(Elf_Word); |
| SHeader.sh_size = SHeader.sh_entsize * Section.Members.size(); |
| |
| auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign); |
| |
| for (auto member : Section.Members) { |
| Elf_Word SIdx; |
| unsigned int sectionIndex = 0; |
| if (member.sectionNameOrType == "GRP_COMDAT") |
| sectionIndex = llvm::ELF::GRP_COMDAT; |
| else if (SN2I.lookup(member.sectionNameOrType, sectionIndex)) { |
| WithColor::error() << "Unknown section referenced: '" |
| << member.sectionNameOrType << "' at YAML section' " |
| << Section.Name << "\n"; |
| return false; |
| } |
| SIdx = sectionIndex; |
| OS.write((const char *)&SIdx, sizeof(SIdx)); |
| } |
| return true; |
| } |
| |
| template <class ELFT> |
| bool ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader, |
| const ELFYAML::MipsABIFlags &Section, |
| ContiguousBlobAccumulator &CBA) { |
| assert(Section.Type == llvm::ELF::SHT_MIPS_ABIFLAGS && |
| "Section type is not SHT_MIPS_ABIFLAGS"); |
| |
| object::Elf_Mips_ABIFlags<ELFT> Flags; |
| zero(Flags); |
| SHeader.sh_entsize = sizeof(Flags); |
| SHeader.sh_size = SHeader.sh_entsize; |
| |
| auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign); |
| Flags.version = Section.Version; |
| Flags.isa_level = Section.ISALevel; |
| Flags.isa_rev = Section.ISARevision; |
| Flags.gpr_size = Section.GPRSize; |
| Flags.cpr1_size = Section.CPR1Size; |
| Flags.cpr2_size = Section.CPR2Size; |
| Flags.fp_abi = Section.FpABI; |
| Flags.isa_ext = Section.ISAExtension; |
| Flags.ases = Section.ASEs; |
| Flags.flags1 = Section.Flags1; |
| Flags.flags2 = Section.Flags2; |
| OS.write((const char *)&Flags, sizeof(Flags)); |
| |
| return true; |
| } |
| |
| template <class ELFT> bool ELFState<ELFT>::buildSectionIndex() { |
| for (unsigned i = 0, e = Doc.Sections.size(); i != e; ++i) { |
| StringRef Name = Doc.Sections[i]->Name; |
| DotShStrtab.add(Name); |
| // "+ 1" to take into account the SHT_NULL entry. |
| if (SN2I.addName(Name, i + 1)) { |
| WithColor::error() << "Repeated section name: '" << Name |
| << "' at YAML section number " << i << ".\n"; |
| return false; |
| } |
| } |
| |
| auto SecNo = 1 + Doc.Sections.size(); |
| // Add special sections after input sections, if necessary. |
| for (const auto &Name : implicitSectionNames()) |
| if (!SN2I.addName(Name, SecNo)) { |
| // Account for this section, since it wasn't in the Doc |
| ++SecNo; |
| DotShStrtab.add(Name); |
| } |
| |
| DotShStrtab.finalize(); |
| return true; |
| } |
| |
| template <class ELFT> |
| bool |
| ELFState<ELFT>::buildSymbolIndex(std::size_t &StartIndex, |
| const std::vector<ELFYAML::Symbol> &Symbols) { |
| for (const auto &Sym : Symbols) { |
| ++StartIndex; |
| if (Sym.Name.empty()) |
| continue; |
| if (SymN2I.addName(Sym.Name, StartIndex)) { |
| WithColor::error() << "Repeated symbol name: '" << Sym.Name << "'.\n"; |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| template <class ELFT> |
| int ELFState<ELFT>::writeELF(raw_ostream &OS, const ELFYAML::Object &Doc) { |
| ELFState<ELFT> State(Doc); |
| if (!State.buildSectionIndex()) |
| return 1; |
| |
| std::size_t StartSymIndex = 0; |
| if (!State.buildSymbolIndex(StartSymIndex, Doc.Symbols.Local) || |
| !State.buildSymbolIndex(StartSymIndex, Doc.Symbols.Global) || |
| !State.buildSymbolIndex(StartSymIndex, Doc.Symbols.Weak)) |
| return 1; |
| |
| Elf_Ehdr Header; |
| State.initELFHeader(Header); |
| |
| // TODO: Flesh out section header support. |
| |
| std::vector<Elf_Phdr> PHeaders; |
| State.initProgramHeaders(PHeaders); |
| |
| // XXX: This offset is tightly coupled with the order that we write |
| // things to `OS`. |
| const size_t SectionContentBeginOffset = Header.e_ehsize + |
| Header.e_phentsize * Header.e_phnum + |
| Header.e_shentsize * Header.e_shnum; |
| ContiguousBlobAccumulator CBA(SectionContentBeginOffset); |
| |
| std::vector<Elf_Shdr> SHeaders; |
| if(!State.initSectionHeaders(SHeaders, CBA)) |
| return 1; |
| |
| // Populate SHeaders with implicit sections not present in the Doc |
| for (const auto &Name : State.implicitSectionNames()) |
| if (State.SN2I.get(Name) >= SHeaders.size()) |
| SHeaders.push_back({}); |
| |
| // Initialize the implicit sections |
| auto Index = State.SN2I.get(".symtab"); |
| State.initSymtabSectionHeader(SHeaders[Index], SymtabType::Static, CBA); |
| Index = State.SN2I.get(".strtab"); |
| State.initStrtabSectionHeader(SHeaders[Index], ".strtab", State.DotStrtab, CBA); |
| Index = State.SN2I.get(".shstrtab"); |
| State.initStrtabSectionHeader(SHeaders[Index], ".shstrtab", State.DotShStrtab, CBA); |
| if (State.hasDynamicSymbols()) { |
| Index = State.SN2I.get(".dynsym"); |
| State.initSymtabSectionHeader(SHeaders[Index], SymtabType::Dynamic, CBA); |
| SHeaders[Index].sh_flags |= ELF::SHF_ALLOC; |
| Index = State.SN2I.get(".dynstr"); |
| State.initStrtabSectionHeader(SHeaders[Index], ".dynstr", State.DotDynstr, CBA); |
| SHeaders[Index].sh_flags |= ELF::SHF_ALLOC; |
| } |
| |
| // Now we can decide segment offsets |
| State.setProgramHeaderLayout(PHeaders, SHeaders); |
| |
| OS.write((const char *)&Header, sizeof(Header)); |
| writeArrayData(OS, makeArrayRef(PHeaders)); |
| writeArrayData(OS, makeArrayRef(SHeaders)); |
| CBA.writeBlobToStream(OS); |
| return 0; |
| } |
| |
| template <class ELFT> bool ELFState<ELFT>::hasDynamicSymbols() const { |
| return Doc.DynamicSymbols.Global.size() > 0 || |
| Doc.DynamicSymbols.Weak.size() > 0 || |
| Doc.DynamicSymbols.Local.size() > 0; |
| } |
| |
| template <class ELFT> SmallVector<const char *, 5> ELFState<ELFT>::implicitSectionNames() const { |
| if (!hasDynamicSymbols()) |
| return {".symtab", ".strtab", ".shstrtab"}; |
| return {".symtab", ".strtab", ".shstrtab", ".dynsym", ".dynstr"}; |
| } |
| |
| static bool is64Bit(const ELFYAML::Object &Doc) { |
| return Doc.Header.Class == ELFYAML::ELF_ELFCLASS(ELF::ELFCLASS64); |
| } |
| |
| static bool isLittleEndian(const ELFYAML::Object &Doc) { |
| return Doc.Header.Data == ELFYAML::ELF_ELFDATA(ELF::ELFDATA2LSB); |
| } |
| |
| int yaml2elf(llvm::ELFYAML::Object &Doc, raw_ostream &Out) { |
| if (is64Bit(Doc)) { |
| if (isLittleEndian(Doc)) |
| return ELFState<object::ELF64LE>::writeELF(Out, Doc); |
| else |
| return ELFState<object::ELF64BE>::writeELF(Out, Doc); |
| } else { |
| if (isLittleEndian(Doc)) |
| return ELFState<object::ELF32LE>::writeELF(Out, Doc); |
| else |
| return ELFState<object::ELF32BE>::writeELF(Out, Doc); |
| } |
| } |
