| //===- Object.h -------------------------------------------------*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_TOOLS_OBJCOPY_OBJECT_H |
| #define LLVM_TOOLS_OBJCOPY_OBJECT_H |
| |
| #include "llvm/ADT/ArrayRef.h" |
| #include "llvm/ADT/StringRef.h" |
| #include "llvm/ADT/Twine.h" |
| #include "llvm/BinaryFormat/ELF.h" |
| #include "llvm/MC/StringTableBuilder.h" |
| #include "llvm/Object/ELFObjectFile.h" |
| #include <cstddef> |
| #include <cstdint> |
| #include <functional> |
| #include <memory> |
| #include <set> |
| #include <vector> |
| |
| namespace llvm { |
| |
| class FileOutputBuffer; |
| class SectionBase; |
| class Segment; |
| |
| class SectionTableRef { |
| private: |
| ArrayRef<std::unique_ptr<SectionBase>> Sections; |
| |
| public: |
| SectionTableRef(ArrayRef<std::unique_ptr<SectionBase>> Secs) |
| : Sections(Secs) {} |
| SectionTableRef(const SectionTableRef &) = default; |
| |
| SectionBase *getSection(uint16_t Index, Twine ErrMsg); |
| |
| template <class T> |
| T *getSectionOfType(uint16_t Index, Twine IndexErrMsg, Twine TypeErrMsg); |
| }; |
| |
| class SectionBase { |
| public: |
| StringRef Name; |
| Segment *ParentSegment = nullptr; |
| uint64_t HeaderOffset; |
| uint64_t OriginalOffset; |
| uint32_t Index; |
| |
| uint64_t Addr = 0; |
| uint64_t Align = 1; |
| uint32_t EntrySize = 0; |
| uint64_t Flags = 0; |
| uint64_t Info = 0; |
| uint64_t Link = ELF::SHN_UNDEF; |
| uint64_t NameIndex = 0; |
| uint64_t Offset = 0; |
| uint64_t Size = 0; |
| uint64_t Type = ELF::SHT_NULL; |
| |
| virtual ~SectionBase() = default; |
| |
| virtual void initialize(SectionTableRef SecTable); |
| virtual void finalize(); |
| virtual void removeSectionReferences(const SectionBase *Sec); |
| template <class ELFT> void writeHeader(FileOutputBuffer &Out) const; |
| virtual void writeSection(FileOutputBuffer &Out) const = 0; |
| }; |
| |
| class Segment { |
| private: |
| struct SectionCompare { |
| bool operator()(const SectionBase *Lhs, const SectionBase *Rhs) const { |
| // Some sections might have the same address if one of them is empty. To |
| // fix this we can use the lexicographic ordering on ->Addr and the |
| // address of the actully stored section. |
| if (Lhs->OriginalOffset == Rhs->OriginalOffset) |
| return Lhs < Rhs; |
| return Lhs->OriginalOffset < Rhs->OriginalOffset; |
| } |
| }; |
| |
| std::set<const SectionBase *, SectionCompare> Sections; |
| ArrayRef<uint8_t> Contents; |
| |
| public: |
| uint64_t Align; |
| uint64_t FileSize; |
| uint32_t Flags; |
| uint32_t Index; |
| uint64_t MemSize; |
| uint64_t Offset; |
| uint64_t PAddr; |
| uint64_t Type; |
| uint64_t VAddr; |
| |
| uint64_t OriginalOffset; |
| Segment *ParentSegment = nullptr; |
| |
| Segment(ArrayRef<uint8_t> Data) : Contents(Data) {} |
| |
| const SectionBase *firstSection() const { |
| if (!Sections.empty()) |
| return *Sections.begin(); |
| return nullptr; |
| } |
| |
| void removeSection(const SectionBase *Sec) { Sections.erase(Sec); } |
| void addSection(const SectionBase *Sec) { Sections.insert(Sec); } |
| template <class ELFT> void writeHeader(FileOutputBuffer &Out) const; |
| void writeSegment(FileOutputBuffer &Out) const; |
| }; |
| |
| class Section : public SectionBase { |
| private: |
| ArrayRef<uint8_t> Contents; |
| |
| public: |
| Section(ArrayRef<uint8_t> Data) : Contents(Data) {} |
| |
| void writeSection(FileOutputBuffer &Out) const override; |
| }; |
| |
| class OwnedDataSection : public SectionBase { |
| private: |
| std::vector<uint8_t> Data; |
| |
| public: |
| OwnedDataSection(StringRef SecName, ArrayRef<uint8_t> Data) |
| : Data(std::begin(Data), std::end(Data)) { |
| Name = SecName; |
| Type = ELF::SHT_PROGBITS; |
| Size = Data.size(); |
| } |
| void writeSection(FileOutputBuffer &Out) const override; |
| }; |
| |
| // There are two types of string tables that can exist, dynamic and not dynamic. |
| // In the dynamic case the string table is allocated. Changing a dynamic string |
| // table would mean altering virtual addresses and thus the memory image. So |
| // dynamic string tables should not have an interface to modify them or |
| // reconstruct them. This type lets us reconstruct a string table. To avoid |
| // this class being used for dynamic string tables (which has happened) the |
| // classof method checks that the particular instance is not allocated. This |
| // then agrees with the makeSection method used to construct most sections. |
| class StringTableSection : public SectionBase { |
| private: |
| StringTableBuilder StrTabBuilder; |
| |
| public: |
| StringTableSection() : StrTabBuilder(StringTableBuilder::ELF) { |
| Type = ELF::SHT_STRTAB; |
| } |
| |
| void addString(StringRef Name); |
| uint32_t findIndex(StringRef Name) const; |
| void finalize() override; |
| void writeSection(FileOutputBuffer &Out) const override; |
| |
| static bool classof(const SectionBase *S) { |
| if (S->Flags & ELF::SHF_ALLOC) |
| return false; |
| return S->Type == ELF::SHT_STRTAB; |
| } |
| }; |
| |
| // Symbols have a st_shndx field that normally stores an index but occasionally |
| // stores a different special value. This enum keeps track of what the st_shndx |
| // field means. Most of the values are just copies of the special SHN_* values. |
| // SYMBOL_SIMPLE_INDEX means that the st_shndx is just an index of a section. |
| enum SymbolShndxType { |
| SYMBOL_SIMPLE_INDEX = 0, |
| SYMBOL_ABS = ELF::SHN_ABS, |
| SYMBOL_COMMON = ELF::SHN_COMMON, |
| SYMBOL_HEXAGON_SCOMMON = ELF::SHN_HEXAGON_SCOMMON, |
| SYMBOL_HEXAGON_SCOMMON_2 = ELF::SHN_HEXAGON_SCOMMON_2, |
| SYMBOL_HEXAGON_SCOMMON_4 = ELF::SHN_HEXAGON_SCOMMON_4, |
| SYMBOL_HEXAGON_SCOMMON_8 = ELF::SHN_HEXAGON_SCOMMON_8, |
| }; |
| |
| struct Symbol { |
| uint8_t Binding; |
| SectionBase *DefinedIn = nullptr; |
| SymbolShndxType ShndxType; |
| uint32_t Index; |
| StringRef Name; |
| uint32_t NameIndex; |
| uint64_t Size; |
| uint8_t Type; |
| uint64_t Value; |
| uint8_t Visibility; |
| |
| uint16_t getShndx() const; |
| }; |
| |
| class SymbolTableSection : public SectionBase { |
| protected: |
| std::vector<std::unique_ptr<Symbol>> Symbols; |
| StringTableSection *SymbolNames = nullptr; |
| |
| using SymPtr = std::unique_ptr<Symbol>; |
| |
| public: |
| void setStrTab(StringTableSection *StrTab) { SymbolNames = StrTab; } |
| void addSymbol(StringRef Name, uint8_t Bind, uint8_t Type, |
| SectionBase *DefinedIn, uint64_t Value, uint8_t Visibility, |
| uint16_t Shndx, uint64_t Sz); |
| void addSymbolNames(); |
| const SectionBase *getStrTab() const { return SymbolNames; } |
| const Symbol *getSymbolByIndex(uint32_t Index) const; |
| void removeSectionReferences(const SectionBase *Sec) override; |
| void initialize(SectionTableRef SecTable) override; |
| void finalize() override; |
| |
| static bool classof(const SectionBase *S) { |
| return S->Type == ELF::SHT_SYMTAB; |
| } |
| }; |
| |
| // Only writeSection depends on the ELF type so we implement it in a subclass. |
| template <class ELFT> class SymbolTableSectionImpl : public SymbolTableSection { |
| void writeSection(FileOutputBuffer &Out) const override; |
| }; |
| |
| struct Relocation { |
| const Symbol *RelocSymbol = nullptr; |
| uint64_t Offset; |
| uint64_t Addend; |
| uint32_t Type; |
| }; |
| |
| // All relocation sections denote relocations to apply to another section. |
| // However, some relocation sections use a dynamic symbol table and others use |
| // a regular symbol table. Because the types of the two symbol tables differ in |
| // our system (because they should behave differently) we can't uniformly |
| // represent all relocations with the same base class if we expose an interface |
| // that mentions the symbol table type. So we split the two base types into two |
| // different classes, one which handles the section the relocation is applied to |
| // and another which handles the symbol table type. The symbol table type is |
| // taken as a type parameter to the class (see RelocSectionWithSymtabBase). |
| class RelocationSectionBase : public SectionBase { |
| protected: |
| SectionBase *SecToApplyRel = nullptr; |
| |
| public: |
| const SectionBase *getSection() const { return SecToApplyRel; } |
| void setSection(SectionBase *Sec) { SecToApplyRel = Sec; } |
| |
| static bool classof(const SectionBase *S) { |
| return S->Type == ELF::SHT_REL || S->Type == ELF::SHT_RELA; |
| } |
| }; |
| |
| // Takes the symbol table type to use as a parameter so that we can deduplicate |
| // that code between the two symbol table types. |
| template <class SymTabType> |
| class RelocSectionWithSymtabBase : public RelocationSectionBase { |
| private: |
| SymTabType *Symbols = nullptr; |
| |
| protected: |
| RelocSectionWithSymtabBase() = default; |
| |
| public: |
| void setSymTab(SymTabType *StrTab) { Symbols = StrTab; } |
| void removeSectionReferences(const SectionBase *Sec) override; |
| void initialize(SectionTableRef SecTable) override; |
| void finalize() override; |
| }; |
| |
| template <class ELFT> |
| class RelocationSection |
| : public RelocSectionWithSymtabBase<SymbolTableSection> { |
| private: |
| using Elf_Rel = typename ELFT::Rel; |
| using Elf_Rela = typename ELFT::Rela; |
| |
| std::vector<Relocation> Relocations; |
| |
| template <class T> void writeRel(T *Buf) const; |
| |
| public: |
| void addRelocation(Relocation Rel) { Relocations.push_back(Rel); } |
| void writeSection(FileOutputBuffer &Out) const override; |
| |
| static bool classof(const SectionBase *S) { |
| if (S->Flags & ELF::SHF_ALLOC) |
| return false; |
| return S->Type == ELF::SHT_REL || S->Type == ELF::SHT_RELA; |
| } |
| }; |
| |
| class SectionWithStrTab : public Section { |
| private: |
| const SectionBase *StrTab = nullptr; |
| |
| public: |
| SectionWithStrTab(ArrayRef<uint8_t> Data) : Section(Data) {} |
| |
| void setStrTab(const SectionBase *StringTable) { StrTab = StringTable; } |
| void removeSectionReferences(const SectionBase *Sec) override; |
| void initialize(SectionTableRef SecTable) override; |
| void finalize() override; |
| static bool classof(const SectionBase *S); |
| }; |
| |
| class DynamicSymbolTableSection : public SectionWithStrTab { |
| public: |
| DynamicSymbolTableSection(ArrayRef<uint8_t> Data) : SectionWithStrTab(Data) {} |
| |
| static bool classof(const SectionBase *S) { |
| return S->Type == ELF::SHT_DYNSYM; |
| } |
| }; |
| |
| class DynamicSection : public SectionWithStrTab { |
| public: |
| DynamicSection(ArrayRef<uint8_t> Data) : SectionWithStrTab(Data) {} |
| |
| static bool classof(const SectionBase *S) { |
| return S->Type == ELF::SHT_DYNAMIC; |
| } |
| }; |
| |
| class DynamicRelocationSection |
| : public RelocSectionWithSymtabBase<DynamicSymbolTableSection> { |
| private: |
| ArrayRef<uint8_t> Contents; |
| |
| public: |
| DynamicRelocationSection(ArrayRef<uint8_t> Data) : Contents(Data) {} |
| |
| void writeSection(FileOutputBuffer &Out) const override; |
| |
| static bool classof(const SectionBase *S) { |
| if (!(S->Flags & ELF::SHF_ALLOC)) |
| return false; |
| return S->Type == ELF::SHT_REL || S->Type == ELF::SHT_RELA; |
| } |
| }; |
| |
| template <class ELFT> class Object { |
| private: |
| using SecPtr = std::unique_ptr<SectionBase>; |
| using SegPtr = std::unique_ptr<Segment>; |
| |
| using Elf_Shdr = typename ELFT::Shdr; |
| using Elf_Ehdr = typename ELFT::Ehdr; |
| using Elf_Phdr = typename ELFT::Phdr; |
| |
| void initSymbolTable(const object::ELFFile<ELFT> &ElfFile, |
| SymbolTableSection *SymTab, SectionTableRef SecTable); |
| SecPtr makeSection(const object::ELFFile<ELFT> &ElfFile, |
| const Elf_Shdr &Shdr); |
| void readProgramHeaders(const object::ELFFile<ELFT> &ElfFile); |
| SectionTableRef readSectionHeaders(const object::ELFFile<ELFT> &ElfFile); |
| |
| protected: |
| StringTableSection *SectionNames = nullptr; |
| SymbolTableSection *SymbolTable = nullptr; |
| std::vector<SecPtr> Sections; |
| std::vector<SegPtr> Segments; |
| |
| void writeHeader(FileOutputBuffer &Out) const; |
| void writeProgramHeaders(FileOutputBuffer &Out) const; |
| void writeSectionData(FileOutputBuffer &Out) const; |
| void writeSectionHeaders(FileOutputBuffer &Out) const; |
| |
| public: |
| uint8_t Ident[16]; |
| uint64_t Entry; |
| uint64_t SHOffset; |
| uint32_t Type; |
| uint32_t Machine; |
| uint32_t Version; |
| uint32_t Flags; |
| bool WriteSectionHeaders = true; |
| |
| Object(const object::ELFObjectFile<ELFT> &Obj); |
| virtual ~Object() = default; |
| |
| const SymbolTableSection *getSymTab() const { return SymbolTable; } |
| const SectionBase *getSectionHeaderStrTab() const { return SectionNames; } |
| void removeSections(std::function<bool(const SectionBase &)> ToRemove); |
| void addSection(StringRef SecName, ArrayRef<uint8_t> Data); |
| virtual size_t totalSize() const = 0; |
| virtual void finalize() = 0; |
| virtual void write(FileOutputBuffer &Out) const = 0; |
| }; |
| |
| template <class ELFT> class ELFObject : public Object<ELFT> { |
| private: |
| using SecPtr = std::unique_ptr<SectionBase>; |
| using SegPtr = std::unique_ptr<Segment>; |
| |
| using Elf_Shdr = typename ELFT::Shdr; |
| using Elf_Ehdr = typename ELFT::Ehdr; |
| using Elf_Phdr = typename ELFT::Phdr; |
| |
| void sortSections(); |
| void assignOffsets(); |
| |
| public: |
| ELFObject(const object::ELFObjectFile<ELFT> &Obj) : Object<ELFT>(Obj) {} |
| |
| void finalize() override; |
| size_t totalSize() const override; |
| void write(FileOutputBuffer &Out) const override; |
| }; |
| |
| template <class ELFT> class BinaryObject : public Object<ELFT> { |
| private: |
| using SecPtr = std::unique_ptr<SectionBase>; |
| using SegPtr = std::unique_ptr<Segment>; |
| |
| uint64_t TotalSize; |
| |
| public: |
| BinaryObject(const object::ELFObjectFile<ELFT> &Obj) : Object<ELFT>(Obj) {} |
| |
| void finalize() override; |
| size_t totalSize() const override; |
| void write(FileOutputBuffer &Out) const override; |
| }; |
| |
| } // end namespace llvm |
| |
| #endif // LLVM_TOOLS_OBJCOPY_OBJECT_H |