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elf2yaml.cpp
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elf2yaml.cpp
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//===------ utils/elf2yaml.cpp - obj2yaml conversion tool -------*- 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
//
//===----------------------------------------------------------------------===//
#include "obj2yaml.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/Twine.h"
#include "llvm/DebugInfo/DWARF/DWARFContext.h"
#include "llvm/Object/ELFObjectFile.h"
#include "llvm/ObjectYAML/DWARFYAML.h"
#include "llvm/ObjectYAML/ELFYAML.h"
#include "llvm/Support/DataExtractor.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/YAMLTraits.h"
using namespace llvm;
namespace {
template <class ELFT>
class ELFDumper {
typedef object::Elf_Sym_Impl<ELFT> Elf_Sym;
typedef typename ELFT::Dyn Elf_Dyn;
typedef typename ELFT::Shdr Elf_Shdr;
typedef typename ELFT::Word Elf_Word;
typedef typename ELFT::Rel Elf_Rel;
typedef typename ELFT::Rela Elf_Rela;
using Elf_Relr = typename ELFT::Relr;
using Elf_Nhdr = typename ELFT::Nhdr;
using Elf_Note = typename ELFT::Note;
ArrayRef<Elf_Shdr> Sections;
ArrayRef<Elf_Sym> SymTable;
DenseMap<StringRef, uint32_t> UsedSectionNames;
std::vector<std::string> SectionNames;
DenseMap<StringRef, uint32_t> UsedSymbolNames;
std::vector<std::string> SymbolNames;
BumpPtrAllocator StringAllocator;
Expected<StringRef> getUniquedSectionName(const Elf_Shdr *Sec);
Expected<StringRef> getUniquedSymbolName(const Elf_Sym *Sym,
StringRef StrTable,
const Elf_Shdr *SymTab);
Expected<StringRef> getSymbolName(uint32_t SymtabNdx, uint32_t SymbolNdx);
const object::ELFFile<ELFT> &Obj;
std::unique_ptr<DWARFContext> DWARFCtx;
ArrayRef<Elf_Word> ShndxTable;
Expected<std::vector<ELFYAML::ProgramHeader>>
dumpProgramHeaders(ArrayRef<std::unique_ptr<ELFYAML::Chunk>> Sections);
Optional<DWARFYAML::Data>
dumpDWARFSections(std::vector<std::unique_ptr<ELFYAML::Chunk>> &Sections);
Error dumpSymbols(const Elf_Shdr *Symtab,
std::vector<ELFYAML::Symbol> &Symbols);
Error dumpSymbol(const Elf_Sym *Sym, const Elf_Shdr *SymTab,
StringRef StrTable, ELFYAML::Symbol &S);
Expected<std::vector<std::unique_ptr<ELFYAML::Chunk>>> dumpSections();
Error dumpCommonSection(const Elf_Shdr *Shdr, ELFYAML::Section &S);
Error dumpCommonRelocationSection(const Elf_Shdr *Shdr,
ELFYAML::RelocationSection &S);
template <class RelT>
Error dumpRelocation(const RelT *Rel, const Elf_Shdr *SymTab,
ELFYAML::Relocation &R);
Expected<ELFYAML::AddrsigSection *> dumpAddrsigSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::LinkerOptionsSection *>
dumpLinkerOptionsSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::DependentLibrariesSection *>
dumpDependentLibrariesSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::CallGraphProfileSection *>
dumpCallGraphProfileSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::DynamicSection *> dumpDynamicSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::RelocationSection *> dumpRelocSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::RelrSection *> dumpRelrSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::RawContentSection *>
dumpContentSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::SymtabShndxSection *>
dumpSymtabShndxSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::NoBitsSection *> dumpNoBitsSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::HashSection *> dumpHashSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::NoteSection *> dumpNoteSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::GnuHashSection *> dumpGnuHashSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::VerdefSection *> dumpVerdefSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::SymverSection *> dumpSymverSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::VerneedSection *> dumpVerneedSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::Group *> dumpGroup(const Elf_Shdr *Shdr);
Expected<ELFYAML::MipsABIFlags *> dumpMipsABIFlags(const Elf_Shdr *Shdr);
Expected<ELFYAML::StackSizesSection *>
dumpStackSizesSection(const Elf_Shdr *Shdr);
Expected<ELFYAML::RawContentSection *>
dumpPlaceholderSection(const Elf_Shdr *Shdr);
bool shouldPrintSection(const ELFYAML::Section &S, const Elf_Shdr &SHdr,
Optional<DWARFYAML::Data> DWARF);
public:
ELFDumper(const object::ELFFile<ELFT> &O, std::unique_ptr<DWARFContext> DCtx);
Expected<ELFYAML::Object *> dump();
};
}
template <class ELFT>
ELFDumper<ELFT>::ELFDumper(const object::ELFFile<ELFT> &O,
std::unique_ptr<DWARFContext> DCtx)
: Obj(O), DWARFCtx(std::move(DCtx)) {}
template <class ELFT>
Expected<StringRef>
ELFDumper<ELFT>::getUniquedSectionName(const Elf_Shdr *Sec) {
unsigned SecIndex = Sec - &Sections[0];
assert(&Sections[SecIndex] == Sec);
if (!SectionNames[SecIndex].empty())
return SectionNames[SecIndex];
auto NameOrErr = Obj.getSectionName(Sec);
if (!NameOrErr)
return NameOrErr;
StringRef Name = *NameOrErr;
// In some specific cases we might have more than one section without a
// name (sh_name == 0). It normally doesn't happen, but when we have this case
// it doesn't make sense to uniquify their names and add noise to the output.
if (Name.empty())
return "";
std::string &Ret = SectionNames[SecIndex];
auto It = UsedSectionNames.insert({Name, 0});
if (!It.second)
Ret = ELFYAML::appendUniqueSuffix(Name, Twine(++It.first->second));
else
Ret = std::string(Name);
return Ret;
}
template <class ELFT>
Expected<StringRef>
ELFDumper<ELFT>::getUniquedSymbolName(const Elf_Sym *Sym, StringRef StrTable,
const Elf_Shdr *SymTab) {
Expected<StringRef> SymbolNameOrErr = Sym->getName(StrTable);
if (!SymbolNameOrErr)
return SymbolNameOrErr;
StringRef Name = *SymbolNameOrErr;
if (Name.empty() && Sym->getType() == ELF::STT_SECTION) {
auto ShdrOrErr = Obj.getSection(Sym, SymTab, ShndxTable);
if (!ShdrOrErr)
return ShdrOrErr.takeError();
return getUniquedSectionName(*ShdrOrErr);
}
// Symbols in .symtab can have duplicate names. For example, it is a common
// situation for local symbols in a relocatable object. Here we assign unique
// suffixes for such symbols so that we can differentiate them.
if (SymTab->sh_type == ELF::SHT_SYMTAB) {
unsigned Index = Sym - SymTable.data();
if (!SymbolNames[Index].empty())
return SymbolNames[Index];
auto It = UsedSymbolNames.insert({Name, 0});
if (!It.second)
SymbolNames[Index] =
ELFYAML::appendUniqueSuffix(Name, Twine(++It.first->second));
else
SymbolNames[Index] = std::string(Name);
return SymbolNames[Index];
}
return Name;
}
template <class ELFT>
bool ELFDumper<ELFT>::shouldPrintSection(const ELFYAML::Section &S,
const Elf_Shdr &SHdr,
Optional<DWARFYAML::Data> DWARF) {
// We only print the SHT_NULL section at index 0 when it
// has at least one non-null field, because yaml2obj
// normally creates the zero section at index 0 implicitly.
if (S.Type == ELF::SHT_NULL && (&SHdr == &Sections[0])) {
const uint8_t *Begin = reinterpret_cast<const uint8_t *>(&SHdr);
const uint8_t *End = Begin + sizeof(Elf_Shdr);
return std::find_if(Begin, End, [](uint8_t V) { return V != 0; }) != End;
}
// Normally we use "DWARF:" to describe contents of DWARF sections. Sometimes
// the content of DWARF sections can be successfully parsed into the "DWARF:"
// entry but their section headers may have special flags, entry size, address
// alignment, etc. We will preserve the header for them under such
// circumstances.
if (DWARF && DWARF->getNonEmptySectionNames().count(S.Name.substr(1))) {
if (const ELFYAML::RawContentSection *RawSec =
dyn_cast<const ELFYAML::RawContentSection>(&S))
return RawSec->Type != ELF::SHT_PROGBITS || RawSec->Flags ||
!RawSec->Link.empty() || RawSec->Info ||
RawSec->AddressAlign != 1 || RawSec->EntSize;
}
// Normally we use "Symbols:" and "DynamicSymbols:" to describe contents of
// symbol tables. We also build and emit corresponding string tables
// implicitly. But sometimes it is important to preserve positions and virtual
// addresses of allocatable sections, e.g. for creating program headers.
// Generally we are trying to reduce noise in the YAML output. Because
// of that we do not print non-allocatable versions of such sections and
// assume they are placed at the end.
if (S.Type == ELF::SHT_STRTAB || S.Type == ELF::SHT_SYMTAB ||
S.Type == ELF::SHT_DYNSYM)
return S.Flags.getValueOr(ELFYAML::ELF_SHF(0)) & ELF::SHF_ALLOC;
return true;
}
template <class ELFT> Expected<ELFYAML::Object *> ELFDumper<ELFT>::dump() {
auto Y = std::make_unique<ELFYAML::Object>();
// Dump header. We do not dump EPh* and ESh* fields. When not explicitly set,
// the values are set by yaml2obj automatically and there is no need to dump
// them here.
Y->Header.Class = ELFYAML::ELF_ELFCLASS(Obj.getHeader()->getFileClass());
Y->Header.Data = ELFYAML::ELF_ELFDATA(Obj.getHeader()->getDataEncoding());
Y->Header.OSABI = Obj.getHeader()->e_ident[ELF::EI_OSABI];
Y->Header.ABIVersion = Obj.getHeader()->e_ident[ELF::EI_ABIVERSION];
Y->Header.Type = Obj.getHeader()->e_type;
Y->Header.Machine = ELFYAML::ELF_EM(Obj.getHeader()->e_machine);
Y->Header.Flags = Obj.getHeader()->e_flags;
Y->Header.Entry = Obj.getHeader()->e_entry;
// Dump sections
auto SectionsOrErr = Obj.sections();
if (!SectionsOrErr)
return SectionsOrErr.takeError();
Sections = *SectionsOrErr;
SectionNames.resize(Sections.size());
// Dump symbols. We need to do this early because other sections might want
// to access the deduplicated symbol names that we also create here.
const Elf_Shdr *SymTab = nullptr;
const Elf_Shdr *SymTabShndx = nullptr;
const Elf_Shdr *DynSymTab = nullptr;
for (const Elf_Shdr &Sec : Sections) {
if (Sec.sh_type == ELF::SHT_SYMTAB) {
SymTab = &Sec;
} else if (Sec.sh_type == ELF::SHT_DYNSYM) {
DynSymTab = &Sec;
} else if (Sec.sh_type == ELF::SHT_SYMTAB_SHNDX) {
// ABI allows us to have one SHT_SYMTAB_SHNDX for each symbol table.
// We only support having the SHT_SYMTAB_SHNDX for SHT_SYMTAB now.
if (SymTabShndx)
return createStringError(
errc::not_supported,
"multiple SHT_SYMTAB_SHNDX sections are not supported");
SymTabShndx = &Sec;
}
}
// We need to locate the SHT_SYMTAB_SHNDX section early, because it might be
// needed for dumping symbols.
if (SymTabShndx) {
if (!SymTab ||
SymTabShndx->sh_link != (unsigned)(SymTab - Sections.begin()))
return createStringError(
errc::not_supported,
"only SHT_SYMTAB_SHNDX associated with SHT_SYMTAB are supported");
auto TableOrErr = Obj.getSHNDXTable(*SymTabShndx);
if (!TableOrErr)
return TableOrErr.takeError();
ShndxTable = *TableOrErr;
}
if (SymTab) {
Y->Symbols.emplace();
if (Error E = dumpSymbols(SymTab, *Y->Symbols))
return std::move(E);
}
if (DynSymTab) {
Y->DynamicSymbols.emplace();
if (Error E = dumpSymbols(DynSymTab, *Y->DynamicSymbols))
return std::move(E);
}
// We dump all sections first. It is simple and allows us to verify that all
// sections are valid and also to generalize the code. But we are not going to
// keep all of them in the final output (see comments for
// 'shouldPrintSection()'). Undesired chunks will be removed later.
Expected<std::vector<std::unique_ptr<ELFYAML::Chunk>>> ChunksOrErr =
dumpSections();
if (!ChunksOrErr)
return ChunksOrErr.takeError();
std::vector<std::unique_ptr<ELFYAML::Chunk>> Chunks = std::move(*ChunksOrErr);
// Dump program headers.
Expected<std::vector<ELFYAML::ProgramHeader>> PhdrsOrErr =
dumpProgramHeaders(Chunks);
if (!PhdrsOrErr)
return PhdrsOrErr.takeError();
Y->ProgramHeaders = std::move(*PhdrsOrErr);
// Dump DWARF sections.
Y->DWARF = dumpDWARFSections(Chunks);
llvm::erase_if(Chunks, [this, &Y](const std::unique_ptr<ELFYAML::Chunk> &C) {
const ELFYAML::Section &S = cast<ELFYAML::Section>(*C.get());
return !shouldPrintSection(S, Sections[S.OriginalSecNdx], Y->DWARF);
});
Y->Chunks = std::move(Chunks);
return Y.release();
}
template <class ELFT>
static bool isInSegment(const ELFYAML::Section &Sec,
const typename ELFT::Shdr &SHdr,
const typename ELFT::Phdr &Phdr) {
if (Sec.Type == ELF::SHT_NULL)
return false;
// A section is within a segment when its location in a file is within the
// [p_offset, p_offset + p_filesz] region.
bool FileOffsetsMatch =
SHdr.sh_offset >= Phdr.p_offset &&
(SHdr.sh_offset + SHdr.sh_size <= Phdr.p_offset + Phdr.p_filesz);
bool VirtualAddressesMatch = SHdr.sh_addr >= Phdr.p_vaddr &&
SHdr.sh_addr <= Phdr.p_vaddr + Phdr.p_memsz;
if (FileOffsetsMatch) {
// An empty section on the edges of a program header can be outside of the
// virtual address space of the segment. This means it is not included in
// the segment and we should ignore it.
if (SHdr.sh_size == 0 && (SHdr.sh_offset == Phdr.p_offset ||
SHdr.sh_offset == Phdr.p_offset + Phdr.p_filesz))
return VirtualAddressesMatch;
return true;
}
// SHT_NOBITS sections usually occupy no physical space in a file. Such
// sections belong to a segment when they reside in the segment's virtual
// address space.
if (Sec.Type != ELF::SHT_NOBITS)
return false;
return VirtualAddressesMatch;
}
template <class ELFT>
Expected<std::vector<ELFYAML::ProgramHeader>>
ELFDumper<ELFT>::dumpProgramHeaders(
ArrayRef<std::unique_ptr<ELFYAML::Chunk>> Chunks) {
std::vector<ELFYAML::ProgramHeader> Ret;
Expected<typename ELFT::PhdrRange> PhdrsOrErr = Obj.program_headers();
if (!PhdrsOrErr)
return PhdrsOrErr.takeError();
for (const typename ELFT::Phdr &Phdr : *PhdrsOrErr) {
ELFYAML::ProgramHeader PH;
PH.Type = Phdr.p_type;
PH.Flags = Phdr.p_flags;
PH.VAddr = Phdr.p_vaddr;
PH.PAddr = Phdr.p_paddr;
// yaml2obj sets the alignment of a segment to 1 by default.
// We do not print the default alignment to reduce noise in the output.
if (Phdr.p_align != 1)
PH.Align = static_cast<llvm::yaml::Hex64>(Phdr.p_align);
// Here we match sections with segments.
// It is not possible to have a non-Section chunk, because
// obj2yaml does not create Fill chunks.
for (const std::unique_ptr<ELFYAML::Chunk> &C : Chunks) {
ELFYAML::Section &S = cast<ELFYAML::Section>(*C.get());
if (isInSegment<ELFT>(S, Sections[S.OriginalSecNdx], Phdr))
PH.Sections.push_back({S.Name});
}
Ret.push_back(PH);
}
return Ret;
}
template <class ELFT>
Optional<DWARFYAML::Data> ELFDumper<ELFT>::dumpDWARFSections(
std::vector<std::unique_ptr<ELFYAML::Chunk>> &Sections) {
DWARFYAML::Data DWARF;
for (std::unique_ptr<ELFYAML::Chunk> &C : Sections) {
if (!C->Name.startswith(".debug_"))
continue;
if (ELFYAML::RawContentSection *RawSec =
dyn_cast<ELFYAML::RawContentSection>(C.get())) {
Error Err = Error::success();
cantFail(std::move(Err));
if (RawSec->Name == ".debug_aranges")
Err = dumpDebugARanges(*DWARFCtx.get(), DWARF);
// If the DWARF section cannot be successfully parsed, emit raw content
// instead of an entry in the DWARF section of the YAML.
if (Err)
consumeError(std::move(Err));
else
RawSec->Content.reset();
}
}
if (DWARF.getNonEmptySectionNames().empty())
return None;
return DWARF;
}
template <class ELFT>
Expected<ELFYAML::RawContentSection *>
ELFDumper<ELFT>::dumpPlaceholderSection(const Elf_Shdr *Shdr) {
auto S = std::make_unique<ELFYAML::RawContentSection>();
if (Error E = dumpCommonSection(Shdr, *S.get()))
return std::move(E);
return S.release();
}
template <class ELFT>
Expected<std::vector<std::unique_ptr<ELFYAML::Chunk>>>
ELFDumper<ELFT>::dumpSections() {
std::vector<std::unique_ptr<ELFYAML::Chunk>> Ret;
auto Add = [&](Expected<ELFYAML::Chunk *> SecOrErr) -> Error {
if (!SecOrErr)
return SecOrErr.takeError();
Ret.emplace_back(*SecOrErr);
return Error::success();
};
auto GetDumper = [this](unsigned Type)
-> std::function<Expected<ELFYAML::Chunk *>(const Elf_Shdr *)> {
switch (Type) {
case ELF::SHT_DYNAMIC:
return [this](const Elf_Shdr *S) { return dumpDynamicSection(S); };
case ELF::SHT_SYMTAB_SHNDX:
return [this](const Elf_Shdr *S) { return dumpSymtabShndxSection(S); };
case ELF::SHT_REL:
case ELF::SHT_RELA:
return [this](const Elf_Shdr *S) { return dumpRelocSection(S); };
case ELF::SHT_RELR:
return [this](const Elf_Shdr *S) { return dumpRelrSection(S); };
case ELF::SHT_GROUP:
return [this](const Elf_Shdr *S) { return dumpGroup(S); };
case ELF::SHT_MIPS_ABIFLAGS:
return [this](const Elf_Shdr *S) { return dumpMipsABIFlags(S); };
case ELF::SHT_NOBITS:
return [this](const Elf_Shdr *S) { return dumpNoBitsSection(S); };
case ELF::SHT_NOTE:
return [this](const Elf_Shdr *S) { return dumpNoteSection(S); };
case ELF::SHT_HASH:
return [this](const Elf_Shdr *S) { return dumpHashSection(S); };
case ELF::SHT_GNU_HASH:
return [this](const Elf_Shdr *S) { return dumpGnuHashSection(S); };
case ELF::SHT_GNU_verdef:
return [this](const Elf_Shdr *S) { return dumpVerdefSection(S); };
case ELF::SHT_GNU_versym:
return [this](const Elf_Shdr *S) { return dumpSymverSection(S); };
case ELF::SHT_GNU_verneed:
return [this](const Elf_Shdr *S) { return dumpVerneedSection(S); };
case ELF::SHT_LLVM_ADDRSIG:
return [this](const Elf_Shdr *S) { return dumpAddrsigSection(S); };
case ELF::SHT_LLVM_LINKER_OPTIONS:
return [this](const Elf_Shdr *S) { return dumpLinkerOptionsSection(S); };
case ELF::SHT_LLVM_DEPENDENT_LIBRARIES:
return [this](const Elf_Shdr *S) {
return dumpDependentLibrariesSection(S);
};
case ELF::SHT_LLVM_CALL_GRAPH_PROFILE:
return
[this](const Elf_Shdr *S) { return dumpCallGraphProfileSection(S); };
case ELF::SHT_STRTAB:
case ELF::SHT_SYMTAB:
case ELF::SHT_DYNSYM:
// The contents of these sections are described by other parts of the YAML
// file. But we still want to dump them, because their properties can be
// important. See comments for 'shouldPrintSection()' for more details.
return [this](const Elf_Shdr *S) { return dumpPlaceholderSection(S); };
default:
return nullptr;
}
};
for (const Elf_Shdr &Sec : Sections) {
// We have dedicated dumping functions for most of the section types.
// Try to use one of them first.
if (std::function<Expected<ELFYAML::Chunk *>(const Elf_Shdr *)> DumpFn =
GetDumper(Sec.sh_type)) {
if (Error E = Add(DumpFn(&Sec)))
return std::move(E);
continue;
}
// Recognize some special SHT_PROGBITS sections by name.
if (Sec.sh_type == ELF::SHT_PROGBITS) {
auto NameOrErr = getUniquedSectionName(&Sec);
if (!NameOrErr)
return NameOrErr.takeError();
if (ELFYAML::StackSizesSection::nameMatches(*NameOrErr)) {
if (Error E = Add(dumpStackSizesSection(&Sec)))
return std::move(E);
continue;
}
}
if (Error E = Add(dumpContentSection(&Sec)))
return std::move(E);
}
return std::move(Ret);
}
template <class ELFT>
Error ELFDumper<ELFT>::dumpSymbols(const Elf_Shdr *Symtab,
std::vector<ELFYAML::Symbol> &Symbols) {
if (!Symtab)
return Error::success();
auto StrTableOrErr = Obj.getStringTableForSymtab(*Symtab);
if (!StrTableOrErr)
return StrTableOrErr.takeError();
StringRef StrTable = *StrTableOrErr;
auto SymtabOrErr = Obj.symbols(Symtab);
if (!SymtabOrErr)
return SymtabOrErr.takeError();
if (Symtab->sh_type == ELF::SHT_SYMTAB) {
SymTable = *SymtabOrErr;
SymbolNames.resize(SymTable.size());
}
for (const auto &Sym : (*SymtabOrErr).drop_front()) {
ELFYAML::Symbol S;
if (auto EC = dumpSymbol(&Sym, Symtab, StrTable, S))
return EC;
Symbols.push_back(S);
}
return Error::success();
}
template <class ELFT>
Error ELFDumper<ELFT>::dumpSymbol(const Elf_Sym *Sym, const Elf_Shdr *SymTab,
StringRef StrTable, ELFYAML::Symbol &S) {
S.Type = Sym->getType();
S.Value = Sym->st_value;
S.Size = Sym->st_size;
S.Other = Sym->st_other;
S.Binding = Sym->getBinding();
Expected<StringRef> SymbolNameOrErr =
getUniquedSymbolName(Sym, StrTable, SymTab);
if (!SymbolNameOrErr)
return SymbolNameOrErr.takeError();
S.Name = SymbolNameOrErr.get();
if (Sym->st_shndx >= ELF::SHN_LORESERVE) {
S.Index = (ELFYAML::ELF_SHN)Sym->st_shndx;
return Error::success();
}
auto ShdrOrErr = Obj.getSection(Sym, SymTab, ShndxTable);
if (!ShdrOrErr)
return ShdrOrErr.takeError();
const Elf_Shdr *Shdr = *ShdrOrErr;
if (!Shdr)
return Error::success();
auto NameOrErr = getUniquedSectionName(Shdr);
if (!NameOrErr)
return NameOrErr.takeError();
S.Section = NameOrErr.get();
return Error::success();
}
template <class ELFT>
template <class RelT>
Error ELFDumper<ELFT>::dumpRelocation(const RelT *Rel, const Elf_Shdr *SymTab,
ELFYAML::Relocation &R) {
R.Type = Rel->getType(Obj.isMips64EL());
R.Offset = Rel->r_offset;
R.Addend = 0;
auto SymOrErr = Obj.getRelocationSymbol(Rel, SymTab);
if (!SymOrErr)
return SymOrErr.takeError();
// We have might have a relocation with symbol index 0,
// e.g. R_X86_64_NONE or R_X86_64_GOTPC32.
const Elf_Sym *Sym = *SymOrErr;
if (!Sym)
return Error::success();
auto StrTabSec = Obj.getSection(SymTab->sh_link);
if (!StrTabSec)
return StrTabSec.takeError();
auto StrTabOrErr = Obj.getStringTable(*StrTabSec);
if (!StrTabOrErr)
return StrTabOrErr.takeError();
Expected<StringRef> NameOrErr =
getUniquedSymbolName(Sym, *StrTabOrErr, SymTab);
if (!NameOrErr)
return NameOrErr.takeError();
R.Symbol = NameOrErr.get();
return Error::success();
}
template <class ELFT>
static unsigned getDefaultShEntSize(ELFYAML::ELF_SHT SecType) {
switch (SecType) {
case ELF::SHT_REL:
return sizeof(typename ELFT::Rel);
case ELF::SHT_RELA:
return sizeof(typename ELFT::Rela);
case ELF::SHT_RELR:
return sizeof(typename ELFT::Relr);
case ELF::SHT_DYNAMIC:
return sizeof(typename ELFT::Dyn);
default:
return 0;
}
}
template <class ELFT>
Error ELFDumper<ELFT>::dumpCommonSection(const Elf_Shdr *Shdr,
ELFYAML::Section &S) {
// Dump fields. We do not dump the ShOffset field. When not explicitly
// set, the value is set by yaml2obj automatically.
S.Type = Shdr->sh_type;
if (Shdr->sh_flags)
S.Flags = static_cast<ELFYAML::ELF_SHF>(Shdr->sh_flags);
if (Shdr->sh_addr)
S.Address = static_cast<uint64_t>(Shdr->sh_addr);
S.AddressAlign = Shdr->sh_addralign;
if (Shdr->sh_entsize != getDefaultShEntSize<ELFT>(S.Type))
S.EntSize = static_cast<llvm::yaml::Hex64>(Shdr->sh_entsize);
S.OriginalSecNdx = Shdr - &Sections[0];
auto NameOrErr = getUniquedSectionName(Shdr);
if (!NameOrErr)
return NameOrErr.takeError();
S.Name = NameOrErr.get();
if (Shdr->sh_link != ELF::SHN_UNDEF) {
auto LinkSection = Obj.getSection(Shdr->sh_link);
if (!LinkSection)
return make_error<StringError>(
"unable to resolve sh_link reference in section '" + S.Name +
"': " + toString(LinkSection.takeError()),
inconvertibleErrorCode());
NameOrErr = getUniquedSectionName(*LinkSection);
if (!NameOrErr)
return NameOrErr.takeError();
S.Link = NameOrErr.get();
}
return Error::success();
}
template <class ELFT>
Error ELFDumper<ELFT>::dumpCommonRelocationSection(
const Elf_Shdr *Shdr, ELFYAML::RelocationSection &S) {
if (Error E = dumpCommonSection(Shdr, S))
return E;
// Having a zero sh_info field is normal: .rela.dyn is a dynamic
// relocation section that normally has no value in this field.
if (!Shdr->sh_info)
return Error::success();
auto InfoSection = Obj.getSection(Shdr->sh_info);
if (!InfoSection)
return InfoSection.takeError();
auto NameOrErr = getUniquedSectionName(*InfoSection);
if (!NameOrErr)
return NameOrErr.takeError();
S.RelocatableSec = NameOrErr.get();
return Error::success();
}
template <class ELFT>
Expected<ELFYAML::StackSizesSection *>
ELFDumper<ELFT>::dumpStackSizesSection(const Elf_Shdr *Shdr) {
auto S = std::make_unique<ELFYAML::StackSizesSection>();
if (Error E = dumpCommonSection(Shdr, *S))
return std::move(E);
auto ContentOrErr = Obj.getSectionContents(Shdr);
if (!ContentOrErr)
return ContentOrErr.takeError();
ArrayRef<uint8_t> Content = *ContentOrErr;
DataExtractor Data(Content, Obj.isLE(), ELFT::Is64Bits ? 8 : 4);
std::vector<ELFYAML::StackSizeEntry> Entries;
DataExtractor::Cursor Cur(0);
while (Cur && Cur.tell() < Content.size()) {
uint64_t Address = Data.getAddress(Cur);
uint64_t Size = Data.getULEB128(Cur);
Entries.push_back({Address, Size});
}
if (Content.empty() || !Cur) {
// If .stack_sizes cannot be decoded, we dump it as an array of bytes.
consumeError(Cur.takeError());
S->Content = yaml::BinaryRef(Content);
} else {
S->Entries = std::move(Entries);
}
return S.release();
}
template <class ELFT>
Expected<ELFYAML::AddrsigSection *>
ELFDumper<ELFT>::dumpAddrsigSection(const Elf_Shdr *Shdr) {
auto S = std::make_unique<ELFYAML::AddrsigSection>();
if (Error E = dumpCommonSection(Shdr, *S))
return std::move(E);
auto ContentOrErr = Obj.getSectionContents(Shdr);
if (!ContentOrErr)
return ContentOrErr.takeError();
ArrayRef<uint8_t> Content = *ContentOrErr;
DataExtractor::Cursor Cur(0);
DataExtractor Data(Content, Obj.isLE(), /*AddressSize=*/0);
std::vector<ELFYAML::YAMLFlowString> Symbols;
while (Cur && Cur.tell() < Content.size()) {
uint64_t SymNdx = Data.getULEB128(Cur);
if (!Cur)
break;
Expected<StringRef> SymbolName = getSymbolName(Shdr->sh_link, SymNdx);
if (!SymbolName || SymbolName->empty()) {
consumeError(SymbolName.takeError());
Symbols.emplace_back(
StringRef(std::to_string(SymNdx)).copy(StringAllocator));
continue;
}
Symbols.emplace_back(*SymbolName);
}
if (Cur) {
S->Symbols = std::move(Symbols);
return S.release();
}
consumeError(Cur.takeError());
S->Content = yaml::BinaryRef(Content);
return S.release();
}
template <class ELFT>
Expected<ELFYAML::LinkerOptionsSection *>
ELFDumper<ELFT>::dumpLinkerOptionsSection(const Elf_Shdr *Shdr) {
auto S = std::make_unique<ELFYAML::LinkerOptionsSection>();
if (Error E = dumpCommonSection(Shdr, *S))
return std::move(E);
auto ContentOrErr = Obj.getSectionContents(Shdr);
if (!ContentOrErr)
return ContentOrErr.takeError();
ArrayRef<uint8_t> Content = *ContentOrErr;
if (Content.empty() || Content.back() != 0) {
S->Content = Content;
return S.release();
}
SmallVector<StringRef, 16> Strings;
toStringRef(Content.drop_back()).split(Strings, '\0');
if (Strings.size() % 2 != 0) {
S->Content = Content;
return S.release();
}
S->Options.emplace();
for (size_t I = 0, E = Strings.size(); I != E; I += 2)
S->Options->push_back({Strings[I], Strings[I + 1]});
return S.release();
}
template <class ELFT>
Expected<ELFYAML::DependentLibrariesSection *>
ELFDumper<ELFT>::dumpDependentLibrariesSection(const Elf_Shdr *Shdr) {
auto DL = std::make_unique<ELFYAML::DependentLibrariesSection>();
if (Error E = dumpCommonSection(Shdr, *DL))
return std::move(E);
Expected<ArrayRef<uint8_t>> ContentOrErr = Obj.getSectionContents(Shdr);
if (!ContentOrErr)
return ContentOrErr.takeError();
ArrayRef<uint8_t> Content = *ContentOrErr;
if (!Content.empty() && Content.back() != 0) {
DL->Content = Content;
return DL.release();
}
DL->Libs.emplace();
for (const uint8_t *I = Content.begin(), *E = Content.end(); I < E;) {
StringRef Lib((const char *)I);
DL->Libs->emplace_back(Lib);
I += Lib.size() + 1;
}
return DL.release();
}
template <class ELFT>
Expected<ELFYAML::CallGraphProfileSection *>
ELFDumper<ELFT>::dumpCallGraphProfileSection(const Elf_Shdr *Shdr) {
auto S = std::make_unique<ELFYAML::CallGraphProfileSection>();
if (Error E = dumpCommonSection(Shdr, *S))
return std::move(E);
Expected<ArrayRef<uint8_t>> ContentOrErr = Obj.getSectionContents(Shdr);
if (!ContentOrErr)
return ContentOrErr.takeError();
ArrayRef<uint8_t> Content = *ContentOrErr;
// Dump the section by using the Content key when it is truncated.
// There is no need to create either "Content" or "Entries" fields when the
// section is empty.
if (Content.empty() || Content.size() % 16 != 0) {
if (!Content.empty())
S->Content = yaml::BinaryRef(Content);
return S.release();
}
std::vector<ELFYAML::CallGraphEntry> Entries(Content.size() / 16);
DataExtractor Data(Content, Obj.isLE(), /*AddressSize=*/0);
DataExtractor::Cursor Cur(0);
auto ReadEntry = [&](ELFYAML::CallGraphEntry &E) {
uint32_t FromSymIndex = Data.getU32(Cur);
uint32_t ToSymIndex = Data.getU32(Cur);
E.Weight = Data.getU64(Cur);
if (!Cur) {
consumeError(Cur.takeError());
return false;
}
Expected<StringRef> From = getSymbolName(Shdr->sh_link, FromSymIndex);
Expected<StringRef> To = getSymbolName(Shdr->sh_link, ToSymIndex);
if (From && To) {
E.From = *From;
E.To = *To;
return true;
}
consumeError(From.takeError());
consumeError(To.takeError());
return false;
};
for (ELFYAML::CallGraphEntry &E : Entries) {
if (ReadEntry(E))
continue;
S->Content = yaml::BinaryRef(Content);
return S.release();
}
S->Entries = std::move(Entries);
return S.release();
}
template <class ELFT>
Expected<ELFYAML::DynamicSection *>
ELFDumper<ELFT>::dumpDynamicSection(const Elf_Shdr *Shdr) {
auto S = std::make_unique<ELFYAML::DynamicSection>();
if (Error E = dumpCommonSection(Shdr, *S))
return std::move(E);
auto DynTagsOrErr = Obj.template getSectionContentsAsArray<Elf_Dyn>(Shdr);
if (!DynTagsOrErr)
return DynTagsOrErr.takeError();
for (const Elf_Dyn &Dyn : *DynTagsOrErr)
S->Entries.push_back({(ELFYAML::ELF_DYNTAG)Dyn.getTag(), Dyn.getVal()});
return S.release();
}
template <class ELFT>
Expected<ELFYAML::RelocationSection *>
ELFDumper<ELFT>::dumpRelocSection(const Elf_Shdr *Shdr) {
auto S = std::make_unique<ELFYAML::RelocationSection>();
if (auto E = dumpCommonRelocationSection(Shdr, *S))
return std::move(E);
auto SymTabOrErr = Obj.getSection(Shdr->sh_link);
if (!SymTabOrErr)
return SymTabOrErr.takeError();
const Elf_Shdr *SymTab = *SymTabOrErr;
if (Shdr->sh_type == ELF::SHT_REL) {
auto Rels = Obj.rels(Shdr);
if (!Rels)
return Rels.takeError();
for (const Elf_Rel &Rel : *Rels) {
ELFYAML::Relocation R;
if (Error E = dumpRelocation(&Rel, SymTab, R))
return std::move(E);
S->Relocations.push_back(R);
}
} else {
auto Rels = Obj.relas(Shdr);
if (!Rels)
return Rels.takeError();
for (const Elf_Rela &Rel : *Rels) {
ELFYAML::Relocation R;
if (Error E = dumpRelocation(&Rel, SymTab, R))
return std::move(E);
R.Addend = Rel.r_addend;
S->Relocations.push_back(R);
}
}
return S.release();
}
template <class ELFT>
Expected<ELFYAML::RelrSection *>
ELFDumper<ELFT>::dumpRelrSection(const Elf_Shdr *Shdr) {
auto S = std::make_unique<ELFYAML::RelrSection>();
if (auto E = dumpCommonSection(Shdr, *S))
return std::move(E);
if (Expected<ArrayRef<Elf_Relr>> Relrs = Obj.relrs(Shdr)) {
S->Entries.emplace();
for (Elf_Relr Rel : *Relrs)
S->Entries->emplace_back(Rel);
return S.release();
} else {
// Ignore. We are going to dump the data as raw content below.
consumeError(Relrs.takeError());
}
Expected<ArrayRef<uint8_t>> ContentOrErr = Obj.getSectionContents(Shdr);
if (!ContentOrErr)
return ContentOrErr.takeError();
S->Content = *ContentOrErr;
return S.release();
}
template <class ELFT>
Expected<ELFYAML::RawContentSection *>
ELFDumper<ELFT>::dumpContentSection(const Elf_Shdr *Shdr) {
auto S = std::make_unique<ELFYAML::RawContentSection>();
if (Error E = dumpCommonSection(Shdr, *S))
return std::move(E);
unsigned SecIndex = Shdr - &Sections[0];
if (SecIndex != 0 || Shdr->sh_type != ELF::SHT_NULL) {
auto ContentOrErr = Obj.getSectionContents(Shdr);
if (!ContentOrErr)
return ContentOrErr.takeError();
ArrayRef<uint8_t> Content = *ContentOrErr;
if (!Content.empty())
S->Content = yaml::BinaryRef(Content);
} else {
S->Size = static_cast<llvm::yaml::Hex64>(Shdr->sh_size);
}
if (Shdr->sh_info)
S->Info = static_cast<llvm::yaml::Hex64>(Shdr->sh_info);
return S.release();
}
template <class ELFT>
Expected<ELFYAML::SymtabShndxSection *>
ELFDumper<ELFT>::dumpSymtabShndxSection(const Elf_Shdr *Shdr) {
auto S = std::make_unique<ELFYAML::SymtabShndxSection>();
if (Error E = dumpCommonSection(Shdr, *S))
return std::move(E);
auto EntriesOrErr = Obj.template getSectionContentsAsArray<Elf_Word>(Shdr);