| //===- yaml2elf - Convert YAML to a ELF object file -----------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| /// |
| /// \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/EndianStream.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); |
| OS.write_zeros(AlignedOffset - CurrentOffset); |
| 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<unsigned> Map; |
| |
| public: |
| /// \Returns false if name is already present in the map. |
| bool addName(StringRef Name, unsigned Ndx) { |
| return Map.insert({Name, Ndx}).second; |
| } |
| /// \Returns false if name is not present in the map. |
| bool lookup(StringRef Name, unsigned &Idx) const { |
| auto I = Map.find(Name); |
| if (I == Map.end()) |
| return false; |
| Idx = I->getValue(); |
| return true; |
| } |
| /// Asserts if name is not present in the map. |
| unsigned get(StringRef Name) const { |
| unsigned Idx; |
| if (lookup(Name, Idx)) |
| return Idx; |
| assert(false && "Expected section not found in index"); |
| return 0; |
| } |
| 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(ArrayRef<ELFYAML::Symbol> Symbols); |
| void initELFHeader(Elf_Ehdr &Header); |
| void initProgramHeaders(std::vector<Elf_Phdr> &PHeaders); |
| bool initImplicitHeader(ELFState<ELFT> &State, ContiguousBlobAccumulator &CBA, |
| Elf_Shdr &Header, StringRef SecName, |
| ELFYAML::Section *YAMLSec); |
| bool initSectionHeaders(ELFState<ELFT> &State, |
| std::vector<Elf_Shdr> &SHeaders, |
| ContiguousBlobAccumulator &CBA); |
| void initSymtabSectionHeader(Elf_Shdr &SHeader, SymtabType STType, |
| ContiguousBlobAccumulator &CBA, |
| ELFYAML::Section *YAMLSec); |
| void initStrtabSectionHeader(Elf_Shdr &SHeader, StringRef Name, |
| StringTableBuilder &STB, |
| ContiguousBlobAccumulator &CBA, |
| ELFYAML::Section *YAMLSec); |
| void setProgramHeaderLayout(std::vector<Elf_Phdr> &PHeaders, |
| std::vector<Elf_Shdr> &SHeaders); |
| bool 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::SymverSection &Section, |
| ContiguousBlobAccumulator &CBA); |
| bool writeSectionContent(Elf_Shdr &SHeader, |
| const ELFYAML::VerneedSection &Section, |
| ContiguousBlobAccumulator &CBA); |
| bool writeSectionContent(Elf_Shdr &SHeader, |
| const ELFYAML::VerdefSection &Section, |
| ContiguousBlobAccumulator &CBA); |
| bool writeSectionContent(Elf_Shdr &SHeader, |
| const ELFYAML::MipsABIFlags &Section, |
| ContiguousBlobAccumulator &CBA); |
| bool writeSectionContent(Elf_Shdr &SHeader, |
| const ELFYAML::DynamicSection &Section, |
| ContiguousBlobAccumulator &CBA); |
| std::vector<StringRef> implicitSectionNames() const; |
| |
| ELFState(const ELFYAML::Object &D) : Doc(D) {} |
| |
| public: |
| static int writeELF(raw_ostream &OS, const ELFYAML::Object &Doc); |
| |
| private: |
| void finalizeStrings(); |
| }; |
| } // 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; |
| Header.e_ident[EI_DATA] = Doc.Header.Data; |
| Header.e_ident[EI_VERSION] = EV_CURRENT; |
| Header.e_ident[EI_OSABI] = Doc.Header.OSABI; |
| Header.e_ident[EI_ABIVERSION] = Doc.Header.ABIVersion; |
| 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 = |
| Doc.Header.SHEntSize ? (uint16_t)*Doc.Header.SHEntSize : sizeof(Elf_Shdr); |
| // Immediately following the ELF header and program headers. |
| Header.e_shoff = |
| Doc.Header.SHOffset |
| ? (uint16_t)*Doc.Header.SHOffset |
| : sizeof(Header) + sizeof(Elf_Phdr) * Doc.ProgramHeaders.size(); |
| Header.e_shnum = |
| Doc.Header.SHNum ? (uint16_t)*Doc.Header.SHNum : SN2I.size() + 1; |
| Header.e_shstrndx = Doc.Header.SHStrNdx ? (uint16_t)*Doc.Header.SHStrNdx |
| : SN2I.get(".shstrtab"); |
| } |
| |
| 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); |
| } |
| } |
| |
| static bool convertSectionIndex(NameToIdxMap &SN2I, StringRef SecName, |
| StringRef IndexSrc, unsigned &IndexDest) { |
| if (!SN2I.lookup(IndexSrc, IndexDest) && !to_integer(IndexSrc, IndexDest)) { |
| WithColor::error() << "Unknown section referenced: '" << IndexSrc |
| << "' at YAML section '" << SecName << "'.\n"; |
| return false; |
| } |
| return true; |
| } |
| |
| template <class ELFT> |
| bool ELFState<ELFT>::initImplicitHeader(ELFState<ELFT> &State, |
| ContiguousBlobAccumulator &CBA, |
| Elf_Shdr &Header, StringRef SecName, |
| ELFYAML::Section *YAMLSec) { |
| // Check if the header was already initialized. |
| if (Header.sh_offset) |
| return false; |
| |
| if (SecName == ".symtab") |
| State.initSymtabSectionHeader(Header, SymtabType::Static, CBA, YAMLSec); |
| else if (SecName == ".strtab") |
| State.initStrtabSectionHeader(Header, SecName, State.DotStrtab, CBA, |
| YAMLSec); |
| else if (SecName == ".shstrtab") |
| State.initStrtabSectionHeader(Header, SecName, State.DotShStrtab, CBA, |
| YAMLSec); |
| |
| else if (SecName == ".dynsym") |
| State.initSymtabSectionHeader(Header, SymtabType::Dynamic, CBA, YAMLSec); |
| else if (SecName == ".dynstr") |
| State.initStrtabSectionHeader(Header, SecName, State.DotDynstr, CBA, |
| YAMLSec); |
| else |
| return false; |
| |
| // Override the sh_offset/sh_size fields if requested. |
| if (YAMLSec) { |
| if (YAMLSec->ShOffset) |
| Header.sh_offset = *YAMLSec->ShOffset; |
| if (YAMLSec->ShSize) |
| Header.sh_size = *YAMLSec->ShSize; |
| } |
| |
| return true; |
| } |
| |
| static StringRef dropUniqueSuffix(StringRef S) { |
| size_t SuffixPos = S.rfind(" ["); |
| if (SuffixPos == StringRef::npos) |
| return S; |
| return S.substr(0, SuffixPos); |
| } |
| |
| template <class ELFT> |
| bool ELFState<ELFT>::initSectionHeaders(ELFState<ELFT> &State, |
| std::vector<Elf_Shdr> &SHeaders, |
| ContiguousBlobAccumulator &CBA) { |
| // Build a list of sections we are going to add implicitly. |
| std::vector<StringRef> ImplicitSections; |
| for (StringRef Name : State.implicitSectionNames()) |
| if (State.SN2I.get(Name) > Doc.Sections.size()) |
| ImplicitSections.push_back(Name); |
| |
| // Ensure SHN_UNDEF entry is present. An all-zero section header is a |
| // valid SHN_UNDEF entry since SHT_NULL == 0. |
| SHeaders.resize(Doc.Sections.size() + ImplicitSections.size() + 1); |
| zero(SHeaders[0]); |
| |
| for (size_t I = 1; I < Doc.Sections.size() + ImplicitSections.size() + 1; ++I) { |
| Elf_Shdr &SHeader = SHeaders[I]; |
| zero(SHeader); |
| ELFYAML::Section *Sec = |
| I > Doc.Sections.size() ? nullptr : Doc.Sections[I - 1].get(); |
| |
| // We have a few sections like string or symbol tables that are usually |
| // added implicitly to the end. However, if they are explicitly specified |
| // in the YAML, we need to write them here. This ensures the file offset |
| // remains correct. |
| StringRef SecName = |
| Sec ? Sec->Name : ImplicitSections[I - Doc.Sections.size() - 1]; |
| if (initImplicitHeader(State, CBA, SHeader, SecName, Sec)) |
| continue; |
| |
| assert(Sec && "It can't be null unless it is an implicit section. But all " |
| "implicit sections should already have been handled above."); |
| |
| SHeader.sh_name = DotShStrtab.getOffset(dropUniqueSuffix(SecName)); |
| SHeader.sh_type = Sec->Type; |
| if (Sec->Flags) |
| SHeader.sh_flags = *Sec->Flags; |
| SHeader.sh_addr = Sec->Address; |
| SHeader.sh_addralign = Sec->AddressAlign; |
| |
| if (!Sec->Link.empty()) { |
| unsigned Index; |
| if (!convertSectionIndex(SN2I, Sec->Name, Sec->Link, Index)) |
| return false; |
| SHeader.sh_link = Index; |
| } |
| |
| if (auto S = dyn_cast<ELFYAML::RawContentSection>(Sec)) { |
| if (!writeSectionContent(SHeader, *S, CBA)) |
| return false; |
| } else if (auto S = dyn_cast<ELFYAML::RelocationSection>(Sec)) { |
| if (!writeSectionContent(SHeader, *S, CBA)) |
| return false; |
| } else if (auto S = dyn_cast<ELFYAML::Group>(Sec)) { |
| if (!writeSectionContent(SHeader, *S, CBA)) |
| return false; |
| } else if (auto S = dyn_cast<ELFYAML::MipsABIFlags>(Sec)) { |
| if (!writeSectionContent(SHeader, *S, CBA)) |
| return false; |
| } else if (auto S = dyn_cast<ELFYAML::NoBitsSection>(Sec)) { |
| 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 if (auto S = dyn_cast<ELFYAML::DynamicSection>(Sec)) { |
| if (!writeSectionContent(SHeader, *S, CBA)) |
| return false; |
| } else if (auto S = dyn_cast<ELFYAML::SymverSection>(Sec)) { |
| if (!writeSectionContent(SHeader, *S, CBA)) |
| return false; |
| } else if (auto S = dyn_cast<ELFYAML::VerneedSection>(Sec)) { |
| if (!writeSectionContent(SHeader, *S, CBA)) |
| return false; |
| } else if (auto S = dyn_cast<ELFYAML::VerdefSection>(Sec)) { |
| if (!writeSectionContent(SHeader, *S, CBA)) |
| return false; |
| } else |
| llvm_unreachable("Unknown section type"); |
| |
| // Override the sh_offset/sh_size fields if requested. |
| if (Sec) { |
| if (Sec->ShOffset) |
| SHeader.sh_offset = *Sec->ShOffset; |
| if (Sec->ShSize) |
| SHeader.sh_size = *Sec->ShSize; |
| } |
| } |
| |
| return true; |
| } |
| |
| static size_t findFirstNonGlobal(ArrayRef<ELFYAML::Symbol> Symbols) { |
| for (size_t I = 0; I < Symbols.size(); ++I) |
| if (Symbols[I].Binding.value != ELF::STB_LOCAL) |
| return I; |
| return Symbols.size(); |
| } |
| |
| static uint64_t writeRawSectionData(raw_ostream &OS, |
| const ELFYAML::RawContentSection &RawSec) { |
| size_t ContentSize = 0; |
| if (RawSec.Content) { |
| RawSec.Content->writeAsBinary(OS); |
| ContentSize = RawSec.Content->binary_size(); |
| } |
| |
| if (!RawSec.Size) |
| return ContentSize; |
| |
| OS.write_zeros(*RawSec.Size - ContentSize); |
| return *RawSec.Size; |
| } |
| |
| template <class ELFT> |
| static std::vector<typename ELFT::Sym> |
| toELFSymbols(NameToIdxMap &SN2I, ArrayRef<ELFYAML::Symbol> Symbols, |
| const StringTableBuilder &Strtab) { |
| using Elf_Sym = typename ELFT::Sym; |
| |
| std::vector<Elf_Sym> Ret; |
| Ret.resize(Symbols.size() + 1); |
| |
| size_t I = 0; |
| for (const auto &Sym : Symbols) { |
| Elf_Sym &Symbol = Ret[++I]; |
| |
| // If NameIndex, which contains the name offset, is explicitly specified, we |
| // use it. This is useful for preparing broken objects. Otherwise, we add |
| // the specified Name to the string table builder to get its offset. |
| if (Sym.NameIndex) |
| Symbol.st_name = *Sym.NameIndex; |
| else if (!Sym.Name.empty()) |
| Symbol.st_name = Strtab.getOffset(dropUniqueSuffix(Sym.Name)); |
| |
| Symbol.setBindingAndType(Sym.Binding, 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; |
| } |
| |
| return Ret; |
| } |
| |
| template <class ELFT> |
| void ELFState<ELFT>::initSymtabSectionHeader(Elf_Shdr &SHeader, |
| SymtabType STType, |
| ContiguousBlobAccumulator &CBA, |
| ELFYAML::Section *YAMLSec) { |
| |
| bool IsStatic = STType == SymtabType::Static; |
| const auto &Symbols = IsStatic ? Doc.Symbols : Doc.DynamicSymbols; |
| |
| ELFYAML::RawContentSection *RawSec = |
| dyn_cast_or_null<ELFYAML::RawContentSection>(YAMLSec); |
| if (RawSec && !Symbols.empty() && (RawSec->Content || RawSec->Size)) { |
| if (RawSec->Content) |
| WithColor::error() << "Cannot specify both `Content` and " + |
| (IsStatic ? Twine("`Symbols`") |
| : Twine("`DynamicSymbols`")) + |
| " for symbol table section '" |
| << RawSec->Name << "'.\n"; |
| if (RawSec->Size) |
| WithColor::error() << "Cannot specify both `Size` and " + |
| (IsStatic ? Twine("`Symbols`") |
| : Twine("`DynamicSymbols`")) + |
| " for symbol table section '" |
| << RawSec->Name << "'.\n"; |
| exit(1); |
| } |
| |
| zero(SHeader); |
| SHeader.sh_name = DotShStrtab.getOffset(IsStatic ? ".symtab" : ".dynsym"); |
| |
| if (YAMLSec) |
| SHeader.sh_type = YAMLSec->Type; |
| else |
| SHeader.sh_type = IsStatic ? ELF::SHT_SYMTAB : ELF::SHT_DYNSYM; |
| |
| if (RawSec && !RawSec->Link.empty()) { |
| // If the Link field is explicitly defined in the document, |
| // we should use it. |
| unsigned Index; |
| if (!convertSectionIndex(SN2I, RawSec->Name, RawSec->Link, Index)) |
| return; |
| SHeader.sh_link = Index; |
| } else { |
| // When we describe the .dynsym section in the document explicitly, it is |
| // allowed to omit the "DynamicSymbols" tag. In this case .dynstr is not |
| // added implicitly and we should be able to leave the Link zeroed if |
| // .dynstr is not defined. |
| unsigned Link = 0; |
| if (IsStatic) |
| Link = SN2I.get(".strtab"); |
| else |
| SN2I.lookup(".dynstr", Link); |
| SHeader.sh_link = Link; |
| } |
| |
| if (YAMLSec && YAMLSec->Flags) |
| SHeader.sh_flags = *YAMLSec->Flags; |
| else if (!IsStatic) |
| SHeader.sh_flags = ELF::SHF_ALLOC; |
| |
| // If the symbol table section is explicitly described in the YAML |
| // then we should set the fields requested. |
| SHeader.sh_info = (RawSec && RawSec->Info) ? (unsigned)(*RawSec->Info) |
| : findFirstNonGlobal(Symbols) + 1; |
| SHeader.sh_entsize = (YAMLSec && YAMLSec->EntSize) |
| ? (uint64_t)(*YAMLSec->EntSize) |
| : sizeof(Elf_Sym); |
| SHeader.sh_addralign = YAMLSec ? (uint64_t)YAMLSec->AddressAlign : 8; |
| SHeader.sh_addr = YAMLSec ? (uint64_t)YAMLSec->Address : 0; |
| |
| auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign); |
| if (RawSec && (RawSec->Content || RawSec->Size)) { |
| assert(Symbols.empty()); |
| SHeader.sh_size = writeRawSectionData(OS, *RawSec); |
| return; |
| } |
| |
| std::vector<Elf_Sym> Syms = |
| toELFSymbols<ELFT>(SN2I, Symbols, IsStatic ? DotStrtab : DotDynstr); |
| writeArrayData(OS, makeArrayRef(Syms)); |
| SHeader.sh_size = arrayDataSize(makeArrayRef(Syms)); |
| } |
| |
| template <class ELFT> |
| void ELFState<ELFT>::initStrtabSectionHeader(Elf_Shdr &SHeader, StringRef Name, |
| StringTableBuilder &STB, |
| ContiguousBlobAccumulator &CBA, |
| ELFYAML::Section *YAMLSec) { |
| zero(SHeader); |
| SHeader.sh_name = DotShStrtab.getOffset(Name); |
| SHeader.sh_type = YAMLSec ? YAMLSec->Type : ELF::SHT_STRTAB; |
| SHeader.sh_addralign = YAMLSec ? (uint64_t)YAMLSec->AddressAlign : 1; |
| |
| ELFYAML::RawContentSection *RawSec = |
| dyn_cast_or_null<ELFYAML::RawContentSection>(YAMLSec); |
| |
| auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign); |
| if (RawSec && (RawSec->Content || RawSec->Size)) { |
| SHeader.sh_size = writeRawSectionData(OS, *RawSec); |
| } else { |
| STB.write(OS); |
| SHeader.sh_size = STB.getSize(); |
| } |
| |
| if (YAMLSec && YAMLSec->EntSize) |
| SHeader.sh_entsize = *YAMLSec->EntSize; |
| |
| if (RawSec && RawSec->Info) |
| SHeader.sh_info = *RawSec->Info; |
| |
| if (YAMLSec && YAMLSec->Flags) |
| SHeader.sh_flags = *YAMLSec->Flags; |
| else if (Name == ".dynstr") |
| SHeader.sh_flags = ELF::SHF_ALLOC; |
| |
| // If the section is explicitly described in the YAML |
| // then we want to use its section address. |
| if (YAMLSec) |
| SHeader.sh_addr = YAMLSec->Address; |
| } |
| |
| 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) { |
| Elf_Phdr &PHeader = PHeaders[PhdrIdx++]; |
| |
| std::vector<Elf_Shdr *> Sections; |
| for (const ELFYAML::SectionName &SecName : YamlPhdr.Sections) { |
| unsigned Index; |
| if (!SN2I.lookup(SecName.Section, Index)) { |
| WithColor::error() << "Unknown section referenced: '" << SecName.Section |
| << "' by program header.\n"; |
| exit(1); |
| } |
| Sections.push_back(&SHeaders[Index]); |
| } |
| |
| if (YamlPhdr.Offset) { |
| PHeader.p_offset = *YamlPhdr.Offset; |
| } else { |
| if (YamlPhdr.Sections.size()) |
| PHeader.p_offset = UINT32_MAX; |
| else |
| PHeader.p_offset = 0; |
| |
| // Find the minimum offset for the program header. |
| for (Elf_Shdr *SHeader : Sections) |
| 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, |
| // if not set explicitly. |
| if (YamlPhdr.FileSize) { |
| PHeader.p_filesz = *YamlPhdr.FileSize; |
| } else { |
| PHeader.p_filesz = 0; |
| for (Elf_Shdr *SHeader : Sections) { |
| 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; |
| } |
| } |
| |
| // If not set explicitly, 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. |
| if (YamlPhdr.MemSize) { |
| PHeader.p_memsz = *YamlPhdr.MemSize; |
| } else { |
| PHeader.p_memsz = PHeader.p_filesz; |
| for (Elf_Shdr *SHeader : Sections) |
| 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 (Elf_Shdr *SHeader : Sections) |
| if (SHeader->sh_offset == PHeader.p_offset) |
| PHeader.p_align = std::max(PHeader.p_align, SHeader->sh_addralign); |
| } |
| } |
| } |
| |
| template <class ELFT> |
| bool ELFState<ELFT>::writeSectionContent( |
| Elf_Shdr &SHeader, const ELFYAML::RawContentSection &Section, |
| ContiguousBlobAccumulator &CBA) { |
| raw_ostream &OS = |
| CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign); |
| SHeader.sh_size = writeRawSectionData(OS, Section); |
| |
| if (Section.EntSize) |
| SHeader.sh_entsize = *Section.EntSize; |
| else if (Section.Type == llvm::ELF::SHT_RELR) |
| SHeader.sh_entsize = sizeof(Elf_Relr); |
| else |
| SHeader.sh_entsize = 0; |
| |
| if (Section.Info) |
| SHeader.sh_info = *Section.Info; |
| |
| return true; |
| } |
| |
| 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(); |
| |
| // For relocation section set link to .symtab by default. |
| if (Section.Link.empty()) |
| SHeader.sh_link = SN2I.get(".symtab"); |
| |
| unsigned Index = 0; |
| if (!Section.RelocatableSec.empty() && |
| !convertSectionIndex(SN2I, Section.Name, Section.RelocatableSec, Index)) |
| return false; |
| SHeader.sh_info = Index; |
| |
| auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign); |
| |
| for (const auto &Rel : Section.Relocations) { |
| unsigned SymIdx = 0; |
| // If a relocation references a symbol, try to look one up in the symbol |
| // table. If it is not there, treat the value as a symbol index. |
| if (Rel.Symbol && !SymN2I.lookup(*Rel.Symbol, SymIdx) && |
| !to_integer(*Rel.Symbol, SymIdx)) { |
| WithColor::error() << "Unknown symbol referenced: '" << *Rel.Symbol |
| << "' at YAML section '" << Section.Name << "'.\n"; |
| return false; |
| } |
| |
| 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) { |
| assert(Section.Type == llvm::ELF::SHT_GROUP && |
| "Section type is not SHT_GROUP"); |
| |
| SHeader.sh_entsize = 4; |
| SHeader.sh_size = SHeader.sh_entsize * Section.Members.size(); |
| |
| unsigned SymIdx; |
| if (!SymN2I.lookup(Section.Signature, SymIdx) && |
| !to_integer(Section.Signature, SymIdx)) { |
| WithColor::error() << "Unknown symbol referenced: '" << Section.Signature |
| << "' at YAML section '" << Section.Name << "'.\n"; |
| return false; |
| } |
| SHeader.sh_info = SymIdx; |
| |
| raw_ostream &OS = |
| CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign); |
| |
| for (const ELFYAML::SectionOrType &Member : Section.Members) { |
| unsigned int SectionIndex = 0; |
| if (Member.sectionNameOrType == "GRP_COMDAT") |
| SectionIndex = llvm::ELF::GRP_COMDAT; |
| else if (!convertSectionIndex(SN2I, Section.Name, Member.sectionNameOrType, |
| SectionIndex)) |
| return false; |
| support::endian::write<uint32_t>(OS, SectionIndex, ELFT::TargetEndianness); |
| } |
| return true; |
| } |
| |
| template <class ELFT> |
| bool ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader, |
| const ELFYAML::SymverSection &Section, |
| ContiguousBlobAccumulator &CBA) { |
| raw_ostream &OS = |
| CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign); |
| for (uint16_t Version : Section.Entries) |
| support::endian::write<uint16_t>(OS, Version, ELFT::TargetEndianness); |
| |
| SHeader.sh_entsize = 2; |
| SHeader.sh_size = Section.Entries.size() * SHeader.sh_entsize; |
| return true; |
| } |
| |
| template <class ELFT> |
| bool ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader, |
| const ELFYAML::VerdefSection &Section, |
| ContiguousBlobAccumulator &CBA) { |
| typedef typename ELFT::Verdef Elf_Verdef; |
| typedef typename ELFT::Verdaux Elf_Verdaux; |
| raw_ostream &OS = |
| CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign); |
| |
| uint64_t AuxCnt = 0; |
| for (size_t I = 0; I < Section.Entries.size(); ++I) { |
| const ELFYAML::VerdefEntry &E = Section.Entries[I]; |
| |
| Elf_Verdef VerDef; |
| VerDef.vd_version = E.Version; |
| VerDef.vd_flags = E.Flags; |
| VerDef.vd_ndx = E.VersionNdx; |
| VerDef.vd_hash = E.Hash; |
| VerDef.vd_aux = sizeof(Elf_Verdef); |
| VerDef.vd_cnt = E.VerNames.size(); |
| if (I == Section.Entries.size() - 1) |
| VerDef.vd_next = 0; |
| else |
| VerDef.vd_next = |
| sizeof(Elf_Verdef) + E.VerNames.size() * sizeof(Elf_Verdaux); |
| OS.write((const char *)&VerDef, sizeof(Elf_Verdef)); |
| |
| for (size_t J = 0; J < E.VerNames.size(); ++J, ++AuxCnt) { |
| Elf_Verdaux VernAux; |
| VernAux.vda_name = DotDynstr.getOffset(E.VerNames[J]); |
| if (J == E.VerNames.size() - 1) |
| VernAux.vda_next = 0; |
| else |
| VernAux.vda_next = sizeof(Elf_Verdaux); |
| OS.write((const char *)&VernAux, sizeof(Elf_Verdaux)); |
| } |
| } |
| |
| SHeader.sh_size = Section.Entries.size() * sizeof(Elf_Verdef) + |
| AuxCnt * sizeof(Elf_Verdaux); |
| SHeader.sh_info = Section.Info; |
| |
| return true; |
| } |
| |
| template <class ELFT> |
| bool ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader, |
| const ELFYAML::VerneedSection &Section, |
| ContiguousBlobAccumulator &CBA) { |
| typedef typename ELFT::Verneed Elf_Verneed; |
| typedef typename ELFT::Vernaux Elf_Vernaux; |
| |
| auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign); |
| |
| uint64_t AuxCnt = 0; |
| for (size_t I = 0; I < Section.VerneedV.size(); ++I) { |
| const ELFYAML::VerneedEntry &VE = Section.VerneedV[I]; |
| |
| Elf_Verneed VerNeed; |
| VerNeed.vn_version = VE.Version; |
| VerNeed.vn_file = DotDynstr.getOffset(VE.File); |
| if (I == Section.VerneedV.size() - 1) |
| VerNeed.vn_next = 0; |
| else |
| VerNeed.vn_next = |
| sizeof(Elf_Verneed) + VE.AuxV.size() * sizeof(Elf_Vernaux); |
| VerNeed.vn_cnt = VE.AuxV.size(); |
| VerNeed.vn_aux = sizeof(Elf_Verneed); |
| OS.write((const char *)&VerNeed, sizeof(Elf_Verneed)); |
| |
| for (size_t J = 0; J < VE.AuxV.size(); ++J, ++AuxCnt) { |
| const ELFYAML::VernauxEntry &VAuxE = VE.AuxV[J]; |
| |
| Elf_Vernaux VernAux; |
| VernAux.vna_hash = VAuxE.Hash; |
| VernAux.vna_flags = VAuxE.Flags; |
| VernAux.vna_other = VAuxE.Other; |
| VernAux.vna_name = DotDynstr.getOffset(VAuxE.Name); |
| if (J == VE.AuxV.size() - 1) |
| VernAux.vna_next = 0; |
| else |
| VernAux.vna_next = sizeof(Elf_Vernaux); |
| OS.write((const char *)&VernAux, sizeof(Elf_Vernaux)); |
| } |
| } |
| |
| SHeader.sh_size = Section.VerneedV.size() * sizeof(Elf_Verneed) + |
| AuxCnt * sizeof(Elf_Vernaux); |
| SHeader.sh_info = Section.Info; |
| |
| 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>::writeSectionContent(Elf_Shdr &SHeader, |
| const ELFYAML::DynamicSection &Section, |
| ContiguousBlobAccumulator &CBA) { |
| typedef typename ELFT::uint uintX_t; |
| |
| assert(Section.Type == llvm::ELF::SHT_DYNAMIC && |
| "Section type is not SHT_DYNAMIC"); |
| |
| if (!Section.Entries.empty() && Section.Content) { |
| WithColor::error() |
| << "Cannot specify both raw content and explicit entries " |
| "for dynamic section '" |
| << Section.Name << "'.\n"; |
| return false; |
| } |
| |
| if (Section.Content) |
| SHeader.sh_size = Section.Content->binary_size(); |
| else |
| SHeader.sh_size = 2 * sizeof(uintX_t) * Section.Entries.size(); |
| if (Section.EntSize) |
| SHeader.sh_entsize = *Section.EntSize; |
| else |
| SHeader.sh_entsize = sizeof(Elf_Dyn); |
| |
| raw_ostream &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign); |
| for (const ELFYAML::DynamicEntry &DE : Section.Entries) { |
| support::endian::write<uintX_t>(OS, DE.Tag, ELFT::TargetEndianness); |
| support::endian::write<uintX_t>(OS, DE.Val, ELFT::TargetEndianness); |
| } |
| if (Section.Content) |
| Section.Content->writeAsBinary(OS); |
| |
| 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(dropUniqueSuffix(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 (StringRef 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(ArrayRef<ELFYAML::Symbol> Symbols) { |
| bool GlobalSymbolSeen = false; |
| std::size_t I = 0; |
| for (const auto &Sym : Symbols) { |
| ++I; |
| |
| StringRef Name = Sym.Name; |
| if (Sym.Binding.value == ELF::STB_LOCAL && GlobalSymbolSeen) { |
| WithColor::error() << "Local symbol '" + Name + |
| "' after global in Symbols list.\n"; |
| return false; |
| } |
| if (Sym.Binding.value != ELF::STB_LOCAL) |
| GlobalSymbolSeen = true; |
| |
| if (!Name.empty() && !SymN2I.addName(Name, I)) { |
| WithColor::error() << "Repeated symbol name: '" << Name << "'.\n"; |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| template <class ELFT> void ELFState<ELFT>::finalizeStrings() { |
| // Add the regular symbol names to .strtab section. |
| for (const ELFYAML::Symbol &Sym : Doc.Symbols) |
| DotStrtab.add(dropUniqueSuffix(Sym.Name)); |
| DotStrtab.finalize(); |
| |
| // Add the dynamic symbol names to .dynstr section. |
| for (const ELFYAML::Symbol &Sym : Doc.DynamicSymbols) |
| DotDynstr.add(dropUniqueSuffix(Sym.Name)); |
| |
| // SHT_GNU_verdef and SHT_GNU_verneed sections might also |
| // add strings to .dynstr section. |
| for (const std::unique_ptr<ELFYAML::Section> &Sec : Doc.Sections) { |
| if (auto VerNeed = dyn_cast<ELFYAML::VerneedSection>(Sec.get())) { |
| for (const ELFYAML::VerneedEntry &VE : VerNeed->VerneedV) { |
| DotDynstr.add(VE.File); |
| for (const ELFYAML::VernauxEntry &Aux : VE.AuxV) |
| DotDynstr.add(Aux.Name); |
| } |
| } else if (auto VerDef = dyn_cast<ELFYAML::VerdefSection>(Sec.get())) { |
| for (const ELFYAML::VerdefEntry &E : VerDef->Entries) |
| for (StringRef Name : E.VerNames) |
| DotDynstr.add(Name); |
| } |
| } |
| |
| DotDynstr.finalize(); |
| } |
| |
| template <class ELFT> |
| int ELFState<ELFT>::writeELF(raw_ostream &OS, const ELFYAML::Object &Doc) { |
| ELFState<ELFT> State(Doc); |
| |
| // Finalize .strtab and .dynstr sections. We do that early because want to |
| // finalize the string table builders before writing the content of the |
| // sections that might want to use them. |
| State.finalizeStrings(); |
| |
| if (!State.buildSectionIndex()) |
| return 1; |
| |
| if (!State.buildSymbolIndex(Doc.Symbols)) |
| 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(State, SHeaders, CBA)) |
| return 1; |
| |
| // 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> |
| std::vector<StringRef> ELFState<ELFT>::implicitSectionNames() const { |
| if (Doc.DynamicSymbols.empty()) |
| return {".symtab", ".strtab", ".shstrtab"}; |
| return {".symtab", ".strtab", ".shstrtab", ".dynsym", ".dynstr"}; |
| } |
| |
| int yaml2elf(llvm::ELFYAML::Object &Doc, raw_ostream &Out) { |
| bool IsLE = Doc.Header.Data == ELFYAML::ELF_ELFDATA(ELF::ELFDATA2LSB); |
| bool Is64Bit = Doc.Header.Class == ELFYAML::ELF_ELFCLASS(ELF::ELFCLASS64); |
| if (Is64Bit) { |
| if (IsLE) |
| return ELFState<object::ELF64LE>::writeELF(Out, Doc); |
| return ELFState<object::ELF64BE>::writeELF(Out, Doc); |
| } |
| if (IsLE) |
| return ELFState<object::ELF32LE>::writeELF(Out, Doc); |
| return ELFState<object::ELF32BE>::writeELF(Out, Doc); |
| } |