llvm/llvm/include/llvm/Object/ELF.h

//===- ELF.h - ELF object file implementation -------------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file declares the ELFFile template class.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_OBJECT_ELF_H
#define LLVM_OBJECT_ELF_H

#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/MapVector.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/Object/ELFTypes.h"
#include "llvm/Object/Error.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/DataExtractor.h"
#include "llvm/Support/Error.h"
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <limits>
#include <type_traits>
#include <utility>

namespace llvm {
namespace object {

struct VerdAux { … };

struct VerDef { … };

struct VernAux { … };

struct VerNeed { … };

struct VersionEntry { … };

StringRef getELFRelocationTypeName(uint32_t Machine, uint32_t Type);
uint32_t getELFRelativeRelocationType(uint32_t Machine);
StringRef getELFSectionTypeName(uint32_t Machine, uint32_t Type);

// Subclasses of ELFFile may need this for template instantiation
inline std::pair<unsigned char, unsigned char>
getElfArchType(StringRef Object) { … }

enum PPCInstrMasks : uint64_t { … };

template <class ELFT> class ELFFile;

template <class T> struct DataRegion { … };

template <class ELFT>
static std::string getSecIndexForError(const ELFFile<ELFT> &Obj,
                                       const typename ELFT::Shdr &Sec) { … }

template <class ELFT>
static std::string describe(const ELFFile<ELFT> &Obj,
                            const typename ELFT::Shdr &Sec) { … }

template <class ELFT>
static std::string getPhdrIndexForError(const ELFFile<ELFT> &Obj,
                                        const typename ELFT::Phdr &Phdr) { … }

static inline Error defaultWarningHandler(const Twine &Msg) { … }

template <class ELFT>
static bool checkSectionOffsets(const typename ELFT::Phdr &Phdr,
                                const typename ELFT::Shdr &Sec) { … }

// Check that an allocatable section belongs to a virtual address
// space of a segment.
template <class ELFT>
static bool checkSectionVMA(const typename ELFT::Phdr &Phdr,
                            const typename ELFT::Shdr &Sec) { … }

template <class ELFT>
static bool isSectionInSegment(const typename ELFT::Phdr &Phdr,
                               const typename ELFT::Shdr &Sec) { … }

// HdrHandler is called once with the number of relocations and whether the
// relocations have addends. EntryHandler is called once per decoded relocation.
template <bool Is64>
static Error decodeCrel(
    ArrayRef<uint8_t> Content,
    function_ref<void(uint64_t /*relocation count*/, bool /*explicit addends*/)>
        HdrHandler,
    function_ref<void(Elf_Crel_Impl<Is64>)> EntryHandler) { … }

template <class ELFT>
class ELFFile { … };

ELF32LEFile;
ELF64LEFile;
ELF32BEFile;
ELF64BEFile;

template <class ELFT>
inline Expected<const typename ELFT::Shdr *>
getSection(typename ELFT::ShdrRange Sections, uint32_t Index) { … }

template <class ELFT>
inline Expected<uint32_t>
getExtendedSymbolTableIndex(const typename ELFT::Sym &Sym, unsigned SymIndex,
                            DataRegion<typename ELFT::Word> ShndxTable) { … }

template <class ELFT>
Expected<uint32_t>
ELFFile<ELFT>::getSectionIndex(const Elf_Sym &Sym, Elf_Sym_Range Syms,
                               DataRegion<Elf_Word> ShndxTable) const { … }

template <class ELFT>
Expected<const typename ELFT::Shdr *>
ELFFile<ELFT>::getSection(const Elf_Sym &Sym, const Elf_Shdr *SymTab,
                          DataRegion<Elf_Word> ShndxTable) const { … }

template <class ELFT>
Expected<const typename ELFT::Shdr *>
ELFFile<ELFT>::getSection(const Elf_Sym &Sym, Elf_Sym_Range Symbols,
                          DataRegion<Elf_Word> ShndxTable) const { … }

template <class ELFT>
Expected<const typename ELFT::Sym *>
ELFFile<ELFT>::getSymbol(const Elf_Shdr *Sec, uint32_t Index) const { … }

template <class ELFT>
template <typename T>
Expected<ArrayRef<T>>
ELFFile<ELFT>::getSectionContentsAsArray(const Elf_Shdr &Sec) const { … }

template <class ELFT>
Expected<ArrayRef<uint8_t>>
ELFFile<ELFT>::getSegmentContents(const Elf_Phdr &Phdr) const { … }

template <class ELFT>
Expected<ArrayRef<uint8_t>>
ELFFile<ELFT>::getSectionContents(const Elf_Shdr &Sec) const { … }

template <class ELFT>
StringRef ELFFile<ELFT>::getRelocationTypeName(uint32_t Type) const { … }

template <class ELFT>
void ELFFile<ELFT>::getRelocationTypeName(uint32_t Type,
                                          SmallVectorImpl<char> &Result) const { … }

template <class ELFT>
uint32_t ELFFile<ELFT>::getRelativeRelocationType() const { … }

template <class ELFT>
Expected<SmallVector<std::optional<VersionEntry>, 0>>
ELFFile<ELFT>::loadVersionMap(const Elf_Shdr *VerNeedSec,
                              const Elf_Shdr *VerDefSec) const { … }

template <class ELFT>
Expected<const typename ELFT::Sym *>
ELFFile<ELFT>::getRelocationSymbol(const Elf_Rel &Rel,
                                   const Elf_Shdr *SymTab) const { … }

template <class ELFT>
Expected<StringRef>
ELFFile<ELFT>::getSectionStringTable(Elf_Shdr_Range Sections,
                                     WarningHandler WarnHandler) const { … }

/// This function finds the number of dynamic symbols using a GNU hash table.
///
/// @param Table The GNU hash table for .dynsym.
template <class ELFT>
static Expected<uint64_t>
getDynSymtabSizeFromGnuHash(const typename ELFT::GnuHash &Table,
                            const void *BufEnd) { … }

/// This function determines the number of dynamic symbols. It reads section
/// headers first. If section headers are not available, the number of
/// symbols will be inferred by parsing dynamic hash tables.
template <class ELFT>
Expected<uint64_t> ELFFile<ELFT>::getDynSymtabSize() const { … }

template <class ELFT> ELFFile<ELFT>::ELFFile(StringRef Object) : … { … }

template <class ELFT>
Expected<ELFFile<ELFT>> ELFFile<ELFT>::create(StringRef Object) { … }

/// Used by llvm-objdump -d (which needs sections for disassembly) to
/// disassemble objects without a section header table (e.g. ET_CORE objects
/// analyzed by linux perf or ET_EXEC with llvm-strip --strip-sections).
template <class ELFT> void ELFFile<ELFT>::createFakeSections() { … }

template <class ELFT>
Expected<typename ELFT::ShdrRange> ELFFile<ELFT>::sections() const { … }

template <class ELFT>
template <typename T>
Expected<const T *> ELFFile<ELFT>::getEntry(uint32_t Section,
                                            uint32_t Entry) const { … }

template <class ELFT>
template <typename T>
Expected<const T *> ELFFile<ELFT>::getEntry(const Elf_Shdr &Section,
                                            uint32_t Entry) const { … }

template <typename ELFT>
Expected<StringRef> ELFFile<ELFT>::getSymbolVersionByIndex(
    uint32_t SymbolVersionIndex, bool &IsDefault,
    SmallVector<std::optional<VersionEntry>, 0> &VersionMap,
    std::optional<bool> IsSymHidden) const { … }

template <class ELFT>
Expected<std::vector<VerDef>>
ELFFile<ELFT>::getVersionDefinitions(const Elf_Shdr &Sec) const { … }

template <class ELFT>
Expected<std::vector<VerNeed>>
ELFFile<ELFT>::getVersionDependencies(const Elf_Shdr &Sec,
                                      WarningHandler WarnHandler) const { … }

template <class ELFT>
Expected<const typename ELFT::Shdr *>
ELFFile<ELFT>::getSection(uint32_t Index) const { … }

template <class ELFT>
Expected<StringRef>
ELFFile<ELFT>::getStringTable(const Elf_Shdr &Section,
                              WarningHandler WarnHandler) const { … }

template <class ELFT>
Expected<ArrayRef<typename ELFT::Word>>
ELFFile<ELFT>::getSHNDXTable(const Elf_Shdr &Section) const { … }

template <class ELFT>
Expected<ArrayRef<typename ELFT::Word>>
ELFFile<ELFT>::getSHNDXTable(const Elf_Shdr &Section,
                             Elf_Shdr_Range Sections) const { … }

template <class ELFT>
Expected<StringRef>
ELFFile<ELFT>::getStringTableForSymtab(const Elf_Shdr &Sec) const { … }

template <class ELFT>
Expected<StringRef>
ELFFile<ELFT>::getStringTableForSymtab(const Elf_Shdr &Sec,
                                       Elf_Shdr_Range Sections) const { … }

template <class ELFT>
Expected<StringRef>
ELFFile<ELFT>::getLinkAsStrtab(const typename ELFT::Shdr &Sec) const { … }

template <class ELFT>
Expected<StringRef>
ELFFile<ELFT>::getSectionName(const Elf_Shdr &Section,
                              WarningHandler WarnHandler) const { … }

template <class ELFT>
Expected<StringRef> ELFFile<ELFT>::getSectionName(const Elf_Shdr &Section,
                                                  StringRef DotShstrtab) const { … }

/// This function returns the hash value for a symbol in the .dynsym section
/// Name of the API remains consistent as specified in the libelf
/// REF : http://www.sco.com/developers/gabi/latest/ch5.dynamic.html#hash
inline uint32_t hashSysV(StringRef SymbolName) { … }

/// This function returns the hash value for a symbol in the .dynsym section
/// for the GNU hash table. The implementation is defined in the GNU hash ABI.
/// REF : https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=bfd/elf.c#l222
inline uint32_t hashGnu(StringRef Name) { … }

extern template class LLVM_TEMPLATE_ABI llvm::object::ELFFile<ELF32LE>;
extern template class LLVM_TEMPLATE_ABI llvm::object::ELFFile<ELF32BE>;
extern template class LLVM_TEMPLATE_ABI llvm::object::ELFFile<ELF64LE>;
extern template class LLVM_TEMPLATE_ABI llvm::object::ELFFile<ELF64BE>;

} // end namespace object
} // end namespace llvm

#endif // LLVM_OBJECT_ELF_H