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llvm-project/llvm/lib/ObjectYAML/ELFEmitter.cpp

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//===- 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 "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/MC/StringTableBuilder.h"
#include "llvm/Object/ELFObjectFile.h"
#include "llvm/ObjectYAML/DWARFEmitter.h"
#include "llvm/ObjectYAML/DWARFYAML.h"
#include "llvm/ObjectYAML/ELFYAML.h"
#include "llvm/ObjectYAML/yaml2obj.h"
#include "llvm/Support/EndianStream.h"
#include "llvm/Support/Errc.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/LEB128.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`).
// The blob might be limited to an arbitrary size. All attempts to write data
// are ignored and the error condition is remembered once the limit is reached.
// Such an approach allows us to simplify the code by delaying error reporting
// and doing it at a convenient time.
namespace {
class ContiguousBlobAccumulator {
const uint64_t InitialOffset;
const uint64_t MaxSize;
SmallVector<char, 128> Buf;
raw_svector_ostream OS;
Error ReachedLimitErr = Error::success();
bool checkLimit(uint64_t Size) {
if (!ReachedLimitErr && getOffset() + Size <= MaxSize)
return true;
if (!ReachedLimitErr)
ReachedLimitErr = createStringError(errc::invalid_argument,
"reached the output size limit");
return false;
}
public:
ContiguousBlobAccumulator(uint64_t BaseOffset, uint64_t SizeLimit)
: InitialOffset(BaseOffset), MaxSize(SizeLimit), OS(Buf) {}
uint64_t tell() const { return OS.tell(); }
uint64_t getOffset() const { return InitialOffset + OS.tell(); }
void writeBlobToStream(raw_ostream &Out) const { Out << OS.str(); }
Error takeLimitError() {
// Request to write 0 bytes to check we did not reach the limit.
checkLimit(0);
return std::move(ReachedLimitErr);
}
/// \returns The new offset.
uint64_t padToAlignment(unsigned Align) {
uint64_t CurrentOffset = getOffset();
if (ReachedLimitErr)
return CurrentOffset;
uint64_t AlignedOffset = alignTo(CurrentOffset, Align == 0 ? 1 : Align);
uint64_t PaddingSize = AlignedOffset - CurrentOffset;
if (!checkLimit(PaddingSize))
return CurrentOffset;
writeZeros(PaddingSize);
return AlignedOffset;
}
raw_ostream *getRawOS(uint64_t Size) {
if (checkLimit(Size))
return &OS;
return nullptr;
}
void writeAsBinary(const yaml::BinaryRef &Bin, uint64_t N = UINT64_MAX) {
if (!checkLimit(Bin.binary_size()))
return;
Bin.writeAsBinary(OS, N);
}
void writeZeros(uint64_t Num) {
if (checkLimit(Num))
OS.write_zeros(Num);
}
void write(const char *Ptr, size_t Size) {
if (checkLimit(Size))
OS.write(Ptr, Size);
}
void write(unsigned char C) {
if (checkLimit(1))
OS.write(C);
}
unsigned writeULEB128(uint64_t Val) {
if (!checkLimit(sizeof(uint64_t)))
return 0;
return encodeULEB128(Val, OS);
}
template <typename T> void write(T Val, support::endianness E) {
if (checkLimit(sizeof(T)))
support::endian::write<T>(OS, Val, E);
}
void updateDataAt(uint64_t Pos, void *Data, size_t Size) {
assert(Pos >= InitialOffset && Pos + Size <= getOffset());
memcpy(&Buf[Pos - InitialOffset], Data, Size);
}
};
// 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.
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(); }
};
namespace {
struct Fragment {
uint64_t Offset;
uint64_t Size;
uint32_t Type;
uint64_t AddrAlign;
};
} // 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 {
LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
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;
NameToIdxMap DynSymN2I;
ELFYAML::Object &Doc;
StringSet<> ExcludedSectionHeaders;
uint64_t LocationCounter = 0;
bool HasError = false;
yaml::ErrorHandler ErrHandler;
void reportError(const Twine &Msg);
void reportError(Error Err);
std::vector<Elf_Sym> toELFSymbols(ArrayRef<ELFYAML::Symbol> Symbols,
const StringTableBuilder &Strtab);
unsigned toSectionIndex(StringRef S, StringRef LocSec, StringRef LocSym = "");
unsigned toSymbolIndex(StringRef S, StringRef LocSec, bool IsDynamic);
void buildSectionIndex();
void buildSymbolIndexes();
void initProgramHeaders(std::vector<Elf_Phdr> &PHeaders);
bool initImplicitHeader(ContiguousBlobAccumulator &CBA, Elf_Shdr &Header,
StringRef SecName, ELFYAML::Section *YAMLSec);
void initSectionHeaders(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 initDWARFSectionHeader(Elf_Shdr &SHeader, StringRef Name,
ContiguousBlobAccumulator &CBA,
ELFYAML::Section *YAMLSec);
void setProgramHeaderLayout(std::vector<Elf_Phdr> &PHeaders,
std::vector<Elf_Shdr> &SHeaders);
std::vector<Fragment>
getPhdrFragments(const ELFYAML::ProgramHeader &Phdr,
ArrayRef<typename ELFT::Shdr> SHeaders);
void finalizeStrings();
void writeELFHeader(raw_ostream &OS);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::NoBitsSection &Section,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::RawContentSection &Section,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::RelocationSection &Section,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::RelrSection &Section,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::GroupSection &Group,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::SymtabShndxSection &Shndx,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::SymverSection &Section,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::VerneedSection &Section,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::VerdefSection &Section,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::ARMIndexTableSection &Section,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::MipsABIFlags &Section,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::DynamicSection &Section,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::StackSizesSection &Section,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::BBAddrMapSection &Section,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::HashSection &Section,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::AddrsigSection &Section,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::NoteSection &Section,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::GnuHashSection &Section,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::LinkerOptionsSection &Section,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::DependentLibrariesSection &Section,
ContiguousBlobAccumulator &CBA);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::CallGraphProfileSection &Section,
ContiguousBlobAccumulator &CBA);
void writeFill(ELFYAML::Fill &Fill, ContiguousBlobAccumulator &CBA);
ELFState(ELFYAML::Object &D, yaml::ErrorHandler EH);
void assignSectionAddress(Elf_Shdr &SHeader, ELFYAML::Section *YAMLSec);
DenseMap<StringRef, size_t> buildSectionHeaderReorderMap();
BumpPtrAllocator StringAlloc;
uint64_t alignToOffset(ContiguousBlobAccumulator &CBA, uint64_t Align,
llvm::Optional<llvm::yaml::Hex64> Offset);
uint64_t getSectionNameOffset(StringRef Name);
public:
static bool writeELF(raw_ostream &OS, ELFYAML::Object &Doc,
yaml::ErrorHandler EH, uint64_t MaxSize);
};
} // 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)); }
template <class ELFT>
ELFState<ELFT>::ELFState(ELFYAML::Object &D, yaml::ErrorHandler EH)
: Doc(D), ErrHandler(EH) {
std::vector<ELFYAML::Section *> Sections = Doc.getSections();
// Insert SHT_NULL section implicitly when it is not defined in YAML.
if (Sections.empty() || Sections.front()->Type != ELF::SHT_NULL)
Doc.Chunks.insert(
Doc.Chunks.begin(),
std::make_unique<ELFYAML::Section>(
ELFYAML::Chunk::ChunkKind::RawContent, /*IsImplicit=*/true));
StringSet<> DocSections;
ELFYAML::SectionHeaderTable *SecHdrTable = nullptr;
for (size_t I = 0; I < Doc.Chunks.size(); ++I) {
const std::unique_ptr<ELFYAML::Chunk> &C = Doc.Chunks[I];
// We might have an explicit section header table declaration.
if (auto S = dyn_cast<ELFYAML::SectionHeaderTable>(C.get())) {
if (SecHdrTable)
reportError("multiple section header tables are not allowed");
SecHdrTable = S;
continue;
}
// We add a technical suffix for each unnamed section/fill. It does not
// affect the output, but allows us to map them by name in the code and
// report better error messages.
if (C->Name.empty()) {
std::string NewName = ELFYAML::appendUniqueSuffix(
/*Name=*/"", "index " + Twine(I));
C->Name = StringRef(NewName).copy(StringAlloc);
assert(ELFYAML::dropUniqueSuffix(C->Name).empty());
}
if (!DocSections.insert(C->Name).second)
reportError("repeated section/fill name: '" + C->Name +
"' at YAML section/fill number " + Twine(I));
}
std::vector<StringRef> ImplicitSections;
if (Doc.DynamicSymbols)
ImplicitSections.insert(ImplicitSections.end(), {".dynsym", ".dynstr"});
if (Doc.Symbols)
ImplicitSections.push_back(".symtab");
if (Doc.DWARF)
for (StringRef DebugSecName : Doc.DWARF->getNonEmptySectionNames()) {
std::string SecName = ("." + DebugSecName).str();
ImplicitSections.push_back(StringRef(SecName).copy(StringAlloc));
}
ImplicitSections.insert(ImplicitSections.end(), {".strtab"});
if (!SecHdrTable || !SecHdrTable->NoHeaders.getValueOr(false))
ImplicitSections.insert(ImplicitSections.end(), {".shstrtab"});
// Insert placeholders for implicit sections that are not
// defined explicitly in YAML.
for (StringRef SecName : ImplicitSections) {
if (DocSections.count(SecName))
continue;
std::unique_ptr<ELFYAML::Section> Sec = std::make_unique<ELFYAML::Section>(
ELFYAML::Chunk::ChunkKind::RawContent, true /*IsImplicit*/);
Sec->Name = SecName;
if (SecName == ".dynsym")
Sec->Type = ELF::SHT_DYNSYM;
else if (SecName == ".symtab")
Sec->Type = ELF::SHT_SYMTAB;
else
Sec->Type = ELF::SHT_STRTAB;
// When the section header table is explicitly defined at the end of the
// sections list, it is reasonable to assume that the user wants to reorder
// section headers, but still wants to place the section header table after
// all sections, like it normally happens. In this case we want to insert
// other implicit sections right before the section header table.
if (Doc.Chunks.back().get() == SecHdrTable)
Doc.Chunks.insert(Doc.Chunks.end() - 1, std::move(Sec));
else
Doc.Chunks.push_back(std::move(Sec));
}
// Insert the section header table implicitly at the end, when it is not
// explicitly defined.
if (!SecHdrTable)
Doc.Chunks.push_back(
std::make_unique<ELFYAML::SectionHeaderTable>(/*IsImplicit=*/true));
}
template <class ELFT>
void ELFState<ELFT>::writeELFHeader(raw_ostream &OS) {
using namespace llvm::ELF;
Elf_Ehdr Header;
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;
if (Doc.Header.Machine)
Header.e_machine = *Doc.Header.Machine;
else
Header.e_machine = EM_NONE;
Header.e_version = EV_CURRENT;
Header.e_entry = Doc.Header.Entry;
Header.e_flags = Doc.Header.Flags;
Header.e_ehsize = sizeof(Elf_Ehdr);
if (Doc.Header.EPhOff)
Header.e_phoff = *Doc.Header.EPhOff;
else if (!Doc.ProgramHeaders.empty())
Header.e_phoff = sizeof(Header);
else
Header.e_phoff = 0;
if (Doc.Header.EPhEntSize)
Header.e_phentsize = *Doc.Header.EPhEntSize;
else if (!Doc.ProgramHeaders.empty())
Header.e_phentsize = sizeof(Elf_Phdr);
else
Header.e_phentsize = 0;
if (Doc.Header.EPhNum)
Header.e_phnum = *Doc.Header.EPhNum;
else if (!Doc.ProgramHeaders.empty())
Header.e_phnum = Doc.ProgramHeaders.size();
else
Header.e_phnum = 0;
Header.e_shentsize = Doc.Header.EShEntSize ? (uint16_t)*Doc.Header.EShEntSize
: sizeof(Elf_Shdr);
const ELFYAML::SectionHeaderTable &SectionHeaders =
Doc.getSectionHeaderTable();
if (Doc.Header.EShOff)
Header.e_shoff = *Doc.Header.EShOff;
else if (SectionHeaders.Offset)
Header.e_shoff = *SectionHeaders.Offset;
else
Header.e_shoff = 0;
if (Doc.Header.EShNum)
Header.e_shnum = *Doc.Header.EShNum;
else
Header.e_shnum = SectionHeaders.getNumHeaders(Doc.getSections().size());
if (Doc.Header.EShStrNdx)
Header.e_shstrndx = *Doc.Header.EShStrNdx;
else if (SectionHeaders.Offset && !ExcludedSectionHeaders.count(".shstrtab"))
Header.e_shstrndx = SN2I.get(".shstrtab");
else
Header.e_shstrndx = 0;
OS.write((const char *)&Header, sizeof(Header));
}
template <class ELFT>
void ELFState<ELFT>::initProgramHeaders(std::vector<Elf_Phdr> &PHeaders) {
DenseMap<StringRef, ELFYAML::Fill *> NameToFill;
DenseMap<StringRef, size_t> NameToIndex;
for (size_t I = 0, E = Doc.Chunks.size(); I != E; ++I) {
if (auto S = dyn_cast<ELFYAML::Fill>(Doc.Chunks[I].get()))
NameToFill[S->Name] = S;
NameToIndex[Doc.Chunks[I]->Name] = I + 1;
}
std::vector<ELFYAML::Section *> Sections = Doc.getSections();
for (size_t I = 0, E = Doc.ProgramHeaders.size(); I != E; ++I) {
ELFYAML::ProgramHeader &YamlPhdr = Doc.ProgramHeaders[I];
Elf_Phdr Phdr;
zero(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);
if (!YamlPhdr.FirstSec && !YamlPhdr.LastSec)
continue;
// Get the index of the section, or 0 in the case when the section doesn't exist.
size_t First = NameToIndex[*YamlPhdr.FirstSec];
if (!First)
reportError("unknown section or fill referenced: '" + *YamlPhdr.FirstSec +
"' by the 'FirstSec' key of the program header with index " +
Twine(I));
size_t Last = NameToIndex[*YamlPhdr.LastSec];
if (!Last)
reportError("unknown section or fill referenced: '" + *YamlPhdr.LastSec +
"' by the 'LastSec' key of the program header with index " +
Twine(I));
if (!First || !Last)
continue;
if (First > Last)
reportError("program header with index " + Twine(I) +
": the section index of " + *YamlPhdr.FirstSec +
" is greater than the index of " + *YamlPhdr.LastSec);
for (size_t I = First; I <= Last; ++I)
YamlPhdr.Chunks.push_back(Doc.Chunks[I - 1].get());
}
}
template <class ELFT>
unsigned ELFState<ELFT>::toSectionIndex(StringRef S, StringRef LocSec,
StringRef LocSym) {
assert(LocSec.empty() || LocSym.empty());
unsigned Index;
if (!SN2I.lookup(S, Index) && !to_integer(S, Index)) {
if (!LocSym.empty())
reportError("unknown section referenced: '" + S + "' by YAML symbol '" +
LocSym + "'");
else
reportError("unknown section referenced: '" + S + "' by YAML section '" +
LocSec + "'");
return 0;
}
const ELFYAML::SectionHeaderTable &SectionHeaders =
Doc.getSectionHeaderTable();
if (SectionHeaders.IsImplicit ||
(SectionHeaders.NoHeaders && !SectionHeaders.NoHeaders.getValue()) ||
SectionHeaders.isDefault())
return Index;
assert(!SectionHeaders.NoHeaders.getValueOr(false) ||
!SectionHeaders.Sections);
size_t FirstExcluded =
SectionHeaders.Sections ? SectionHeaders.Sections->size() : 0;
if (Index >= FirstExcluded) {
if (LocSym.empty())
reportError("unable to link '" + LocSec + "' to excluded section '" + S +
"'");
else
reportError("excluded section referenced: '" + S + "' by symbol '" +
LocSym + "'");
}
return Index;
}
template <class ELFT>
unsigned ELFState<ELFT>::toSymbolIndex(StringRef S, StringRef LocSec,
bool IsDynamic) {
const NameToIdxMap &SymMap = IsDynamic ? DynSymN2I : SymN2I;
unsigned Index;
// Here we try to look up S in the symbol table. If it is not there,
// treat its value as a symbol index.
if (!SymMap.lookup(S, Index) && !to_integer(S, Index)) {
reportError("unknown symbol referenced: '" + S + "' by YAML section '" +
LocSec + "'");
return 0;
}
return Index;
}
template <class ELFT>
static void overrideFields(ELFYAML::Section *From, typename ELFT::Shdr &To) {
if (!From)
return;
if (From->ShAddrAlign)
To.sh_addralign = *From->ShAddrAlign;
if (From->ShFlags)
To.sh_flags = *From->ShFlags;
if (From->ShName)
To.sh_name = *From->ShName;
if (From->ShOffset)
To.sh_offset = *From->ShOffset;
if (From->ShSize)
To.sh_size = *From->ShSize;
if (From->ShType)
To.sh_type = *From->ShType;
}
template <class ELFT>
bool ELFState<ELFT>::initImplicitHeader(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")
initSymtabSectionHeader(Header, SymtabType::Static, CBA, YAMLSec);
else if (SecName == ".strtab")
initStrtabSectionHeader(Header, SecName, DotStrtab, CBA, YAMLSec);
else if (SecName == ".shstrtab")
initStrtabSectionHeader(Header, SecName, DotShStrtab, CBA, YAMLSec);
else if (SecName == ".dynsym")
initSymtabSectionHeader(Header, SymtabType::Dynamic, CBA, YAMLSec);
else if (SecName == ".dynstr")
initStrtabSectionHeader(Header, SecName, DotDynstr, CBA, YAMLSec);
else if (SecName.startswith(".debug_")) {
// If a ".debug_*" section's type is a preserved one, e.g., SHT_DYNAMIC, we
// will not treat it as a debug section.
if (YAMLSec && !isa<ELFYAML::RawContentSection>(YAMLSec))
return false;
initDWARFSectionHeader(Header, SecName, CBA, YAMLSec);
} else
return false;
LocationCounter += Header.sh_size;
// Override section fields if requested.
overrideFields<ELFT>(YAMLSec, Header);
return true;
}
constexpr char SuffixStart = '(';
constexpr char SuffixEnd = ')';
std::string llvm::ELFYAML::appendUniqueSuffix(StringRef Name,
const Twine &Msg) {
// Do not add a space when a Name is empty.
std::string Ret = Name.empty() ? "" : Name.str() + ' ';
return Ret + (Twine(SuffixStart) + Msg + Twine(SuffixEnd)).str();
}
StringRef llvm::ELFYAML::dropUniqueSuffix(StringRef S) {
if (S.empty() || S.back() != SuffixEnd)
return S;
// A special case for empty names. See appendUniqueSuffix() above.
size_t SuffixPos = S.rfind(SuffixStart);
if (SuffixPos == 0)
return "";
if (SuffixPos == StringRef::npos || S[SuffixPos - 1] != ' ')
return S;
return S.substr(0, SuffixPos - 1);
}
template <class ELFT>
uint64_t ELFState<ELFT>::getSectionNameOffset(StringRef Name) {
// If a section is excluded from section headers, we do not save its name in
// the string table.
if (ExcludedSectionHeaders.count(Name))
return 0;
return DotShStrtab.getOffset(Name);
}
static uint64_t writeContent(ContiguousBlobAccumulator &CBA,
const Optional<yaml::BinaryRef> &Content,
const Optional<llvm::yaml::Hex64> &Size) {
size_t ContentSize = 0;
if (Content) {
CBA.writeAsBinary(*Content);
ContentSize = Content->binary_size();
}
if (!Size)
return ContentSize;
CBA.writeZeros(*Size - ContentSize);
return *Size;
}
static StringRef getDefaultLinkSec(unsigned SecType) {
switch (SecType) {
case ELF::SHT_REL:
case ELF::SHT_RELA:
case ELF::SHT_GROUP:
case ELF::SHT_LLVM_CALL_GRAPH_PROFILE:
case ELF::SHT_LLVM_ADDRSIG:
return ".symtab";
case ELF::SHT_GNU_versym:
case ELF::SHT_HASH:
case ELF::SHT_GNU_HASH:
return ".dynsym";
case ELF::SHT_DYNSYM:
case ELF::SHT_GNU_verdef:
case ELF::SHT_GNU_verneed:
return ".dynstr";
case ELF::SHT_SYMTAB:
return ".strtab";
default:
return "";
}
}
template <class ELFT>
void ELFState<ELFT>::initSectionHeaders(std::vector<Elf_Shdr> &SHeaders,
ContiguousBlobAccumulator &CBA) {
// Ensure SHN_UNDEF entry is present. An all-zero section header is a
// valid SHN_UNDEF entry since SHT_NULL == 0.
SHeaders.resize(Doc.getSections().size());
for (const std::unique_ptr<ELFYAML::Chunk> &D : Doc.Chunks) {
if (ELFYAML::Fill *S = dyn_cast<ELFYAML::Fill>(D.get())) {
S->Offset = alignToOffset(CBA, /*Align=*/1, S->Offset);
writeFill(*S, CBA);
LocationCounter += S->Size;
continue;
}
if (ELFYAML::SectionHeaderTable *S =
dyn_cast<ELFYAML::SectionHeaderTable>(D.get())) {
if (S->NoHeaders.getValueOr(false))
continue;
if (!S->Offset)
S->Offset = alignToOffset(CBA, sizeof(typename ELFT::uint),
/*Offset=*/None);
else
S->Offset = alignToOffset(CBA, /*Align=*/1, S->Offset);
uint64_t Size = S->getNumHeaders(SHeaders.size()) * sizeof(Elf_Shdr);
// The full section header information might be not available here, so
// fill the space with zeroes as a placeholder.
CBA.writeZeros(Size);
LocationCounter += Size;
continue;
}
ELFYAML::Section *Sec = cast<ELFYAML::Section>(D.get());
bool IsFirstUndefSection = Sec == Doc.getSections().front();
if (IsFirstUndefSection && Sec->IsImplicit)
continue;
Elf_Shdr &SHeader = SHeaders[SN2I.get(Sec->Name)];
if (Sec->Link) {
SHeader.sh_link = toSectionIndex(*Sec->Link, Sec->Name);
} else {
StringRef LinkSec = getDefaultLinkSec(Sec->Type);
unsigned Link = 0;
if (!LinkSec.empty() && !ExcludedSectionHeaders.count(LinkSec) &&
SN2I.lookup(LinkSec, Link))
SHeader.sh_link = Link;
}
if (Sec->EntSize)
SHeader.sh_entsize = *Sec->EntSize;
else
SHeader.sh_entsize = ELFYAML::getDefaultShEntSize<ELFT>(
Doc.Header.Machine.getValueOr(ELF::EM_NONE), Sec->Type, Sec->Name);
// 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.
if (initImplicitHeader(CBA, SHeader, Sec->Name,
Sec->IsImplicit ? nullptr : 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 =
getSectionNameOffset(ELFYAML::dropUniqueSuffix(Sec->Name));
SHeader.sh_type = Sec->Type;
if (Sec->Flags)
SHeader.sh_flags = *Sec->Flags;
SHeader.sh_addralign = Sec->AddressAlign;
// Set the offset for all sections, except the SHN_UNDEF section with index
// 0 when not explicitly requested.
if (!IsFirstUndefSection || Sec->Offset)
SHeader.sh_offset = alignToOffset(CBA, SHeader.sh_addralign, Sec->Offset);
assignSectionAddress(SHeader, Sec);
if (IsFirstUndefSection) {
if (auto RawSec = dyn_cast<ELFYAML::RawContentSection>(Sec)) {
// We do not write any content for special SHN_UNDEF section.
if (RawSec->Size)
SHeader.sh_size = *RawSec->Size;
if (RawSec->Info)
SHeader.sh_info = *RawSec->Info;
}
LocationCounter += SHeader.sh_size;
overrideFields<ELFT>(Sec, SHeader);
continue;
}
if (!isa<ELFYAML::NoBitsSection>(Sec) && (Sec->Content || Sec->Size))
SHeader.sh_size = writeContent(CBA, Sec->Content, Sec->Size);
if (auto S = dyn_cast<ELFYAML::RawContentSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::SymtabShndxSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::RelocationSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::RelrSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::GroupSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::ARMIndexTableSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::MipsABIFlags>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::NoBitsSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::DynamicSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::SymverSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::VerneedSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::VerdefSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::StackSizesSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::HashSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::AddrsigSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::LinkerOptionsSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::NoteSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::GnuHashSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::DependentLibrariesSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::CallGraphProfileSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else if (auto S = dyn_cast<ELFYAML::BBAddrMapSection>(Sec)) {
writeSectionContent(SHeader, *S, CBA);
} else {
llvm_unreachable("Unknown section type");
}
LocationCounter += SHeader.sh_size;
// Override section fields if requested.
overrideFields<ELFT>(Sec, SHeader);
}
}
template <class ELFT>
void ELFState<ELFT>::assignSectionAddress(Elf_Shdr &SHeader,
ELFYAML::Section *YAMLSec) {
if (YAMLSec && YAMLSec->Address) {
SHeader.sh_addr = *YAMLSec->Address;
LocationCounter = *YAMLSec->Address;
return;
}
// sh_addr represents the address in the memory image of a process. Sections
// in a relocatable object file or non-allocatable sections do not need
// sh_addr assignment.
if (Doc.Header.Type.value == ELF::ET_REL ||
!(SHeader.sh_flags & ELF::SHF_ALLOC))
return;
LocationCounter =
alignTo(LocationCounter, SHeader.sh_addralign ? SHeader.sh_addralign : 1);
SHeader.sh_addr = LocationCounter;
}
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();
}
template <class ELFT>
std::vector<typename ELFT::Sym>
ELFState<ELFT>::toELFSymbols(ArrayRef<ELFYAML::Symbol> Symbols,
const StringTableBuilder &Strtab) {
std::vector<Elf_Sym> Ret;
Ret.resize(Symbols.size() + 1);
size_t I = 0;
for (const ELFYAML::Symbol &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.StName)
Symbol.st_name = *Sym.StName;
else if (!Sym.Name.empty())
Symbol.st_name = Strtab.getOffset(ELFYAML::dropUniqueSuffix(Sym.Name));
Symbol.setBindingAndType(Sym.Binding, Sym.Type);
if (Sym.Section)
Symbol.st_shndx = toSectionIndex(*Sym.Section, "", Sym.Name);
else if (Sym.Index)
Symbol.st_shndx = *Sym.Index;
Symbol.st_value = Sym.Value.getValueOr(yaml::Hex64(0));
Symbol.st_other = Sym.Other ? *Sym.Other : 0;
Symbol.st_size = Sym.Size.getValueOr(yaml::Hex64(0));
}
return Ret;
}
template <class ELFT>
void ELFState<ELFT>::initSymtabSectionHeader(Elf_Shdr &SHeader,
SymtabType STType,
ContiguousBlobAccumulator &CBA,
ELFYAML::Section *YAMLSec) {
bool IsStatic = STType == SymtabType::Static;
ArrayRef<ELFYAML::Symbol> Symbols;
if (IsStatic && Doc.Symbols)
Symbols = *Doc.Symbols;
else if (!IsStatic && Doc.DynamicSymbols)
Symbols = *Doc.DynamicSymbols;
ELFYAML::RawContentSection *RawSec =
dyn_cast_or_null<ELFYAML::RawContentSection>(YAMLSec);
if (RawSec && (RawSec->Content || RawSec->Size)) {
bool HasSymbolsDescription =
(IsStatic && Doc.Symbols) || (!IsStatic && Doc.DynamicSymbols);
if (HasSymbolsDescription) {
StringRef Property = (IsStatic ? "`Symbols`" : "`DynamicSymbols`");
if (RawSec->Content)
reportError("cannot specify both `Content` and " + Property +
" for symbol table section '" + RawSec->Name + "'");
if (RawSec->Size)
reportError("cannot specify both `Size` and " + Property +
" for symbol table section '" + RawSec->Name + "'");
return;
}
}
SHeader.sh_name = getSectionNameOffset(IsStatic ? ".symtab" : ".dynsym");
if (YAMLSec)
SHeader.sh_type = YAMLSec->Type;
else
SHeader.sh_type = IsStatic ? ELF::SHT_SYMTAB : ELF::SHT_DYNSYM;
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_addralign = YAMLSec ? (uint64_t)YAMLSec->AddressAlign : 8;
assignSectionAddress(SHeader, YAMLSec);
SHeader.sh_offset =
alignToOffset(CBA, SHeader.sh_addralign, RawSec ? RawSec->Offset : None);
if (RawSec && (RawSec->Content || RawSec->Size)) {
assert(Symbols.empty());
SHeader.sh_size = writeContent(CBA, RawSec->Content, RawSec->Size);
return;
}
std::vector<Elf_Sym> Syms =
toELFSymbols(Symbols, IsStatic ? DotStrtab : DotDynstr);
SHeader.sh_size = Syms.size() * sizeof(Elf_Sym);
CBA.write((const char *)Syms.data(), SHeader.sh_size);
}
template <class ELFT>
void ELFState<ELFT>::initStrtabSectionHeader(Elf_Shdr &SHeader, StringRef Name,
StringTableBuilder &STB,
ContiguousBlobAccumulator &CBA,
ELFYAML::Section *YAMLSec) {
SHeader.sh_name = getSectionNameOffset(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);
SHeader.sh_offset = alignToOffset(CBA, SHeader.sh_addralign,
YAMLSec ? YAMLSec->Offset : None);
if (RawSec && (RawSec->Content || RawSec->Size)) {
SHeader.sh_size = writeContent(CBA, RawSec->Content, RawSec->Size);
} else {
if (raw_ostream *OS = CBA.getRawOS(STB.getSize()))
STB.write(*OS);
SHeader.sh_size = STB.getSize();
}
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;
assignSectionAddress(SHeader, YAMLSec);
}
static bool shouldEmitDWARF(DWARFYAML::Data &DWARF, StringRef Name) {
SetVector<StringRef> DebugSecNames = DWARF.getNonEmptySectionNames();
return Name.consume_front(".") && DebugSecNames.count(Name);
}
template <class ELFT>
Expected<uint64_t> emitDWARF(typename ELFT::Shdr &SHeader, StringRef Name,
const DWARFYAML::Data &DWARF,
ContiguousBlobAccumulator &CBA) {
// We are unable to predict the size of debug data, so we request to write 0
// bytes. This should always return us an output stream unless CBA is already
// in an error state.
raw_ostream *OS = CBA.getRawOS(0);
if (!OS)
return 0;
uint64_t BeginOffset = CBA.tell();
auto EmitFunc = DWARFYAML::getDWARFEmitterByName(Name.substr(1));
if (Error Err = EmitFunc(*OS, DWARF))
return std::move(Err);
return CBA.tell() - BeginOffset;
}
template <class ELFT>
void ELFState<ELFT>::initDWARFSectionHeader(Elf_Shdr &SHeader, StringRef Name,
ContiguousBlobAccumulator &CBA,
ELFYAML::Section *YAMLSec) {
SHeader.sh_name = getSectionNameOffset(ELFYAML::dropUniqueSuffix(Name));
SHeader.sh_type = YAMLSec ? YAMLSec->Type : ELF::SHT_PROGBITS;
SHeader.sh_addralign = YAMLSec ? (uint64_t)YAMLSec->AddressAlign : 1;
SHeader.sh_offset = alignToOffset(CBA, SHeader.sh_addralign,
YAMLSec ? YAMLSec->Offset : None);
ELFYAML::RawContentSection *RawSec =
dyn_cast_or_null<ELFYAML::RawContentSection>(YAMLSec);
if (Doc.DWARF && shouldEmitDWARF(*Doc.DWARF, Name)) {
if (RawSec && (RawSec->Content || RawSec->Size))
reportError("cannot specify section '" + Name +
"' contents in the 'DWARF' entry and the 'Content' "
"or 'Size' in the 'Sections' entry at the same time");
else {
if (Expected<uint64_t> ShSizeOrErr =
emitDWARF<ELFT>(SHeader, Name, *Doc.DWARF, CBA))
SHeader.sh_size = *ShSizeOrErr;
else
reportError(ShSizeOrErr.takeError());
}
} else if (RawSec)
SHeader.sh_size = writeContent(CBA, RawSec->Content, RawSec->Size);
else
llvm_unreachable("debug sections can only be initialized via the 'DWARF' "
"entry or a RawContentSection");
if (RawSec && RawSec->Info)
SHeader.sh_info = *RawSec->Info;
if (YAMLSec && YAMLSec->Flags)
SHeader.sh_flags = *YAMLSec->Flags;
else if (Name == ".debug_str")
SHeader.sh_flags = ELF::SHF_MERGE | ELF::SHF_STRINGS;
assignSectionAddress(SHeader, YAMLSec);
}
template <class ELFT> void ELFState<ELFT>::reportError(const Twine &Msg) {
ErrHandler(Msg);
HasError = true;
}
template <class ELFT> void ELFState<ELFT>::reportError(Error Err) {
handleAllErrors(std::move(Err), [&](const ErrorInfoBase &Err) {
reportError(Err.message());
});
}
template <class ELFT>
std::vector<Fragment>
ELFState<ELFT>::getPhdrFragments(const ELFYAML::ProgramHeader &Phdr,
ArrayRef<Elf_Shdr> SHeaders) {
std::vector<Fragment> Ret;
for (const ELFYAML::Chunk *C : Phdr.Chunks) {
if (const ELFYAML::Fill *F = dyn_cast<ELFYAML::Fill>(C)) {
Ret.push_back({*F->Offset, F->Size, llvm::ELF::SHT_PROGBITS,
/*ShAddrAlign=*/1});
continue;
}
const ELFYAML::Section *S = cast<ELFYAML::Section>(C);
const Elf_Shdr &H = SHeaders[SN2I.get(S->Name)];
Ret.push_back({H.sh_offset, H.sh_size, H.sh_type, H.sh_addralign});
}
return Ret;
}
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<Fragment> Fragments = getPhdrFragments(YamlPhdr, SHeaders);
if (!llvm::is_sorted(Fragments, [](const Fragment &A, const Fragment &B) {
return A.Offset < B.Offset;
}))
reportError("sections in the program header with index " +
Twine(PhdrIdx) + " are not sorted by their file offset");
if (YamlPhdr.Offset) {
if (!Fragments.empty() && *YamlPhdr.Offset > Fragments.front().Offset)
reportError("'Offset' for segment with index " + Twine(PhdrIdx) +
" must be less than or equal to the minimum file offset of "
"all included sections (0x" +
Twine::utohexstr(Fragments.front().Offset) + ")");
PHeader.p_offset = *YamlPhdr.Offset;
} else if (!Fragments.empty()) {
PHeader.p_offset = Fragments.front().Offset;
}
// Set the file size if not set explicitly.
if (YamlPhdr.FileSize) {
PHeader.p_filesz = *YamlPhdr.FileSize;
} else if (!Fragments.empty()) {
uint64_t FileSize = Fragments.back().Offset - PHeader.p_offset;
// SHT_NOBITS sections occupy no physical space in a file, we should not
// take their sizes into account when calculating the file size of a
// segment.
if (Fragments.back().Type != llvm::ELF::SHT_NOBITS)
FileSize += Fragments.back().Size;
PHeader.p_filesz = FileSize;
}
// Find the maximum offset of the end of a section in order to set p_memsz.
uint64_t MemOffset = PHeader.p_offset;
for (const Fragment &F : Fragments)
MemOffset = std::max(MemOffset, F.Offset + F.Size);
// Set the memory size if not set explicitly.
PHeader.p_memsz = YamlPhdr.MemSize ? uint64_t(*YamlPhdr.MemSize)
: MemOffset - PHeader.p_offset;
if (YamlPhdr.Align) {
PHeader.p_align = *YamlPhdr.Align;
} else {
// Set the alignment of the segment to be the maximum alignment of the
// sections so that by default the segment has a valid and sensible
// alignment.
PHeader.p_align = 1;
for (const Fragment &F : Fragments)
PHeader.p_align = std::max((uint64_t)PHeader.p_align, F.AddrAlign);
}
}
}
bool llvm::ELFYAML::shouldAllocateFileSpace(
ArrayRef<ELFYAML::ProgramHeader> Phdrs, const ELFYAML::NoBitsSection &S) {
for (const ELFYAML::ProgramHeader &PH : Phdrs) {
auto It = llvm::find_if(
PH.Chunks, [&](ELFYAML::Chunk *C) { return C->Name == S.Name; });
if (std::any_of(It, PH.Chunks.end(), [](ELFYAML::Chunk *C) {
return (isa<ELFYAML::Fill>(C) ||
cast<ELFYAML::Section>(C)->Type != ELF::SHT_NOBITS);
}))
return true;
}
return false;
}
template <class ELFT>
void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::NoBitsSection &S,
ContiguousBlobAccumulator &CBA) {
if (!S.Size)
return;
SHeader.sh_size = *S.Size;
// When a nobits section is followed by a non-nobits section or fill
// in the same segment, we allocate the file space for it. This behavior
// matches linkers.
if (shouldAllocateFileSpace(Doc.ProgramHeaders, S))
CBA.writeZeros(*S.Size);
}
template <class ELFT>
void ELFState<ELFT>::writeSectionContent(
Elf_Shdr &SHeader, const ELFYAML::RawContentSection &Section,
ContiguousBlobAccumulator &CBA) {
if (Section.Info)
SHeader.sh_info = *Section.Info;
}
static bool isMips64EL(const ELFYAML::Object &Obj) {
return Obj.getMachine() == llvm::ELF::EM_MIPS &&
Obj.Header.Class == ELFYAML::ELF_ELFCLASS(ELF::ELFCLASS64) &&
Obj.Header.Data == ELFYAML::ELF_ELFDATA(ELF::ELFDATA2LSB);
}
template <class ELFT>
void 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");
if (!Section.RelocatableSec.empty())
SHeader.sh_info = toSectionIndex(Section.RelocatableSec, Section.Name);
if (!Section.Relocations)
return;
const bool IsRela = Section.Type == llvm::ELF::SHT_RELA;
for (const ELFYAML::Relocation &Rel : *Section.Relocations) {
const bool IsDynamic = Section.Link && (*Section.Link == ".dynsym");
unsigned SymIdx =
Rel.Symbol ? toSymbolIndex(*Rel.Symbol, Section.Name, IsDynamic) : 0;
if (IsRela) {
Elf_Rela REntry;
zero(REntry);
REntry.r_offset = Rel.Offset;
REntry.r_addend = Rel.Addend;
REntry.setSymbolAndType(SymIdx, Rel.Type, isMips64EL(Doc));
CBA.write((const char *)&REntry, sizeof(REntry));
} else {
Elf_Rel REntry;
zero(REntry);
REntry.r_offset = Rel.Offset;
REntry.setSymbolAndType(SymIdx, Rel.Type, isMips64EL(Doc));
CBA.write((const char *)&REntry, sizeof(REntry));
}
}
SHeader.sh_size = (IsRela ? sizeof(Elf_Rela) : sizeof(Elf_Rel)) *
Section.Relocations->size();
}
template <class ELFT>
void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::RelrSection &Section,
ContiguousBlobAccumulator &CBA) {
if (!Section.Entries)
return;
for (llvm::yaml::Hex64 E : *Section.Entries) {
if (!ELFT::Is64Bits && E > UINT32_MAX)
reportError(Section.Name + ": the value is too large for 32-bits: 0x" +
Twine::utohexstr(E));
CBA.write<uintX_t>(E, ELFT::TargetEndianness);
}
SHeader.sh_size = sizeof(uintX_t) * Section.Entries->size();
}
template <class ELFT>
void ELFState<ELFT>::writeSectionContent(
Elf_Shdr &SHeader, const ELFYAML::SymtabShndxSection &Shndx,
ContiguousBlobAccumulator &CBA) {
if (Shndx.Content || Shndx.Size) {
SHeader.sh_size = writeContent(CBA, Shndx.Content, Shndx.Size);
return;
}
if (!Shndx.Entries)
return;
for (uint32_t E : *Shndx.Entries)
CBA.write<uint32_t>(E, ELFT::TargetEndianness);
SHeader.sh_size = Shndx.Entries->size() * SHeader.sh_entsize;
}
template <class ELFT>
void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::GroupSection &Section,
ContiguousBlobAccumulator &CBA) {
assert(Section.Type == llvm::ELF::SHT_GROUP &&
"Section type is not SHT_GROUP");
if (Section.Signature)
SHeader.sh_info =
toSymbolIndex(*Section.Signature, Section.Name, /*IsDynamic=*/false);
if (!Section.Members)
return;
for (const ELFYAML::SectionOrType &Member : *Section.Members) {
unsigned int SectionIndex = 0;
if (Member.sectionNameOrType == "GRP_COMDAT")
SectionIndex = llvm::ELF::GRP_COMDAT;
else
SectionIndex = toSectionIndex(Member.sectionNameOrType, Section.Name);
CBA.write<uint32_t>(SectionIndex, ELFT::TargetEndianness);
}
SHeader.sh_size = SHeader.sh_entsize * Section.Members->size();
}
template <class ELFT>
void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::SymverSection &Section,
ContiguousBlobAccumulator &CBA) {
if (!Section.Entries)
return;
for (uint16_t Version : *Section.Entries)
CBA.write<uint16_t>(Version, ELFT::TargetEndianness);
SHeader.sh_size = Section.Entries->size() * SHeader.sh_entsize;
}
template <class ELFT>
void ELFState<ELFT>::writeSectionContent(
Elf_Shdr &SHeader, const ELFYAML::StackSizesSection &Section,
ContiguousBlobAccumulator &CBA) {
if (!Section.Entries)
return;
if (!Section.Entries)
return;
for (const ELFYAML::StackSizeEntry &E : *Section.Entries) {
CBA.write<uintX_t>(E.Address, ELFT::TargetEndianness);
SHeader.sh_size += sizeof(uintX_t) + CBA.writeULEB128(E.Size);
}
}
template <class ELFT>
void ELFState<ELFT>::writeSectionContent(
Elf_Shdr &SHeader, const ELFYAML::BBAddrMapSection &Section,
ContiguousBlobAccumulator &CBA) {
if (!Section.Entries)
return;
for (const ELFYAML::BBAddrMapEntry &E : *Section.Entries) {
// Write the address of the function.
CBA.write<uintX_t>(E.Address, ELFT::TargetEndianness);
// Write number of BBEntries (number of basic blocks in the function).
size_t NumBlocks = E.BBEntries ? E.BBEntries->size() : 0;
SHeader.sh_size += sizeof(uintX_t) + CBA.writeULEB128(NumBlocks);
if (!NumBlocks)
continue;
// Write all BBEntries.
for (const ELFYAML::BBAddrMapEntry::BBEntry &BBE : *E.BBEntries)
SHeader.sh_size += CBA.writeULEB128(BBE.AddressOffset) +
CBA.writeULEB128(BBE.Size) +
CBA.writeULEB128(BBE.Metadata);
}
}
template <class ELFT>
void ELFState<ELFT>::writeSectionContent(
Elf_Shdr &SHeader, const ELFYAML::LinkerOptionsSection &Section,
ContiguousBlobAccumulator &CBA) {
if (!Section.Options)
return;
for (const ELFYAML::LinkerOption &LO : *Section.Options) {
CBA.write(LO.Key.data(), LO.Key.size());
CBA.write('\0');
CBA.write(LO.Value.data(), LO.Value.size());
CBA.write('\0');
SHeader.sh_size += (LO.Key.size() + LO.Value.size() + 2);
}
}
template <class ELFT>
void ELFState<ELFT>::writeSectionContent(
Elf_Shdr &SHeader, const ELFYAML::DependentLibrariesSection &Section,
ContiguousBlobAccumulator &CBA) {
if (!Section.Libs)
return;
for (StringRef Lib : *Section.Libs) {
CBA.write(Lib.data(), Lib.size());
CBA.write('\0');
SHeader.sh_size += Lib.size() + 1;
}
}
template <class ELFT>
uint64_t
ELFState<ELFT>::alignToOffset(ContiguousBlobAccumulator &CBA, uint64_t Align,
llvm::Optional<llvm::yaml::Hex64> Offset) {
uint64_t CurrentOffset = CBA.getOffset();
uint64_t AlignedOffset;
if (Offset) {
if ((uint64_t)*Offset < CurrentOffset) {
reportError("the 'Offset' value (0x" +
Twine::utohexstr((uint64_t)*Offset) + ") goes backward");
return CurrentOffset;
}
// We ignore an alignment when an explicit offset has been requested.
AlignedOffset = *Offset;
} else {
AlignedOffset = alignTo(CurrentOffset, std::max(Align, (uint64_t)1));
}
CBA.writeZeros(AlignedOffset - CurrentOffset);
return AlignedOffset;
}
template <class ELFT>
void ELFState<ELFT>::writeSectionContent(
Elf_Shdr &SHeader, const ELFYAML::CallGraphProfileSection &Section,
ContiguousBlobAccumulator &CBA) {
if (!Section.Entries)
return;
for (const ELFYAML::CallGraphEntry &E : *Section.Entries) {
unsigned From = toSymbolIndex(E.From, Section.Name, /*IsDynamic=*/false);
unsigned To = toSymbolIndex(E.To, Section.Name, /*IsDynamic=*/false);
CBA.write<uint32_t>(From, ELFT::TargetEndianness);
CBA.write<uint32_t>(To, ELFT::TargetEndianness);
CBA.write<uint64_t>(E.Weight, ELFT::TargetEndianness);
SHeader.sh_size += 16;
}
}
template <class ELFT>
void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::HashSection &Section,
ContiguousBlobAccumulator &CBA) {
if (!Section.Bucket)
return;
if (!Section.Bucket)
return;
CBA.write<uint32_t>(
Section.NBucket.getValueOr(llvm::yaml::Hex64(Section.Bucket->size())),
ELFT::TargetEndianness);
CBA.write<uint32_t>(
Section.NChain.getValueOr(llvm::yaml::Hex64(Section.Chain->size())),
ELFT::TargetEndianness);
for (uint32_t Val : *Section.Bucket)
CBA.write<uint32_t>(Val, ELFT::TargetEndianness);
for (uint32_t Val : *Section.Chain)
CBA.write<uint32_t>(Val, ELFT::TargetEndianness);
SHeader.sh_size = (2 + Section.Bucket->size() + Section.Chain->size()) * 4;
}
template <class ELFT>
void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::VerdefSection &Section,
ContiguousBlobAccumulator &CBA) {
if (Section.Info)
SHeader.sh_info = *Section.Info;
else if (Section.Entries)
SHeader.sh_info = Section.Entries->size();
if (!Section.Entries)
return;
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.getValueOr(1);
VerDef.vd_flags = E.Flags.getValueOr(0);
VerDef.vd_ndx = E.VersionNdx.getValueOr(0);
VerDef.vd_hash = E.Hash.getValueOr(0);
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);
CBA.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);
CBA.write((const char *)&VernAux, sizeof(Elf_Verdaux));
}
}
SHeader.sh_size = Section.Entries->size() * sizeof(Elf_Verdef) +
AuxCnt * sizeof(Elf_Verdaux);
}
template <class ELFT>
void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::VerneedSection &Section,
ContiguousBlobAccumulator &CBA) {
if (Section.Info)
SHeader.sh_info = *Section.Info;
else if (Section.VerneedV)
SHeader.sh_info = Section.VerneedV->size();
if (!Section.VerneedV)
return;
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);
CBA.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);
CBA.write((const char *)&VernAux, sizeof(Elf_Vernaux));
}
}
SHeader.sh_size = Section.VerneedV->size() * sizeof(Elf_Verneed) +
AuxCnt * sizeof(Elf_Vernaux);
}
template <class ELFT>
void ELFState<ELFT>::writeSectionContent(
Elf_Shdr &SHeader, const ELFYAML::ARMIndexTableSection &Section,
ContiguousBlobAccumulator &CBA) {
if (!Section.Entries)
return;
for (const ELFYAML::ARMIndexTableEntry &E : *Section.Entries) {
CBA.write<uint32_t>(E.Offset, ELFT::TargetEndianness);
CBA.write<uint32_t>(E.Value, ELFT::TargetEndianness);
}
SHeader.sh_size = Section.Entries->size() * 8;
}
template <class ELFT>
void 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_size = SHeader.sh_entsize;
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;
CBA.write((const char *)&Flags, sizeof(Flags));
}
template <class ELFT>
void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::DynamicSection &Section,
ContiguousBlobAccumulator &CBA) {
assert(Section.Type == llvm::ELF::SHT_DYNAMIC &&
"Section type is not SHT_DYNAMIC");
if (!Section.Entries)
return;
for (const ELFYAML::DynamicEntry &DE : *Section.Entries) {
CBA.write<uintX_t>(DE.Tag, ELFT::TargetEndianness);
CBA.write<uintX_t>(DE.Val, ELFT::TargetEndianness);
}
SHeader.sh_size = 2 * sizeof(uintX_t) * Section.Entries->size();
}
template <class ELFT>
void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::AddrsigSection &Section,
ContiguousBlobAccumulator &CBA) {
if (!Section.Symbols)
return;
if (!Section.Symbols)
return;
for (StringRef Sym : *Section.Symbols)
SHeader.sh_size +=
CBA.writeULEB128(toSymbolIndex(Sym, Section.Name, /*IsDynamic=*/false));
}
template <class ELFT>
void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::NoteSection &Section,
ContiguousBlobAccumulator &CBA) {
if (!Section.Notes)
return;
uint64_t Offset = CBA.tell();
for (const ELFYAML::NoteEntry &NE : *Section.Notes) {
// Write name size.
if (NE.Name.empty())
CBA.write<uint32_t>(0, ELFT::TargetEndianness);
else
CBA.write<uint32_t>(NE.Name.size() + 1, ELFT::TargetEndianness);
// Write description size.
if (NE.Desc.binary_size() == 0)
CBA.write<uint32_t>(0, ELFT::TargetEndianness);
else
CBA.write<uint32_t>(NE.Desc.binary_size(), ELFT::TargetEndianness);
// Write type.
CBA.write<uint32_t>(NE.Type, ELFT::TargetEndianness);
// Write name, null terminator and padding.
if (!NE.Name.empty()) {
CBA.write(NE.Name.data(), NE.Name.size());
CBA.write('\0');
CBA.padToAlignment(4);
}
// Write description and padding.
if (NE.Desc.binary_size() != 0) {
CBA.writeAsBinary(NE.Desc);
CBA.padToAlignment(4);
}
}
SHeader.sh_size = CBA.tell() - Offset;
}
template <class ELFT>
void ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::GnuHashSection &Section,
ContiguousBlobAccumulator &CBA) {
if (!Section.HashBuckets)
return;
if (!Section.Header)
return;
// We write the header first, starting with the hash buckets count. Normally
// it is the number of entries in HashBuckets, but the "NBuckets" property can
// be used to override this field, which is useful for producing broken
// objects.
if (Section.Header->NBuckets)
CBA.write<uint32_t>(*Section.Header->NBuckets, ELFT::TargetEndianness);
else
CBA.write<uint32_t>(Section.HashBuckets->size(), ELFT::TargetEndianness);
// Write the index of the first symbol in the dynamic symbol table accessible
// via the hash table.
CBA.write<uint32_t>(Section.Header->SymNdx, ELFT::TargetEndianness);
// Write the number of words in the Bloom filter. As above, the "MaskWords"
// property can be used to set this field to any value.
if (Section.Header->MaskWords)
CBA.write<uint32_t>(*Section.Header->MaskWords, ELFT::TargetEndianness);
else
CBA.write<uint32_t>(Section.BloomFilter->size(), ELFT::TargetEndianness);
// Write the shift constant used by the Bloom filter.
CBA.write<uint32_t>(Section.Header->Shift2, ELFT::TargetEndianness);
// We've finished writing the header. Now write the Bloom filter.
for (llvm::yaml::Hex64 Val : *Section.BloomFilter)
CBA.write<uintX_t>(Val, ELFT::TargetEndianness);
// Write an array of hash buckets.
for (llvm::yaml::Hex32 Val : *Section.HashBuckets)
CBA.write<uint32_t>(Val, ELFT::TargetEndianness);
// Write an array of hash values.
for (llvm::yaml::Hex32 Val : *Section.HashValues)
CBA.write<uint32_t>(Val, ELFT::TargetEndianness);
SHeader.sh_size = 16 /*Header size*/ +
Section.BloomFilter->size() * sizeof(typename ELFT::uint) +
Section.HashBuckets->size() * 4 +
Section.HashValues->size() * 4;
}
template <class ELFT>
void ELFState<ELFT>::writeFill(ELFYAML::Fill &Fill,
ContiguousBlobAccumulator &CBA) {
size_t PatternSize = Fill.Pattern ? Fill.Pattern->binary_size() : 0;
if (!PatternSize) {
CBA.writeZeros(Fill.Size);
return;
}
// Fill the content with the specified pattern.
uint64_t Written = 0;
for (; Written + PatternSize <= Fill.Size; Written += PatternSize)
CBA.writeAsBinary(*Fill.Pattern);
CBA.writeAsBinary(*Fill.Pattern, Fill.Size - Written);
}
template <class ELFT>
DenseMap<StringRef, size_t> ELFState<ELFT>::buildSectionHeaderReorderMap() {
const ELFYAML::SectionHeaderTable &SectionHeaders =
Doc.getSectionHeaderTable();
if (SectionHeaders.IsImplicit || SectionHeaders.NoHeaders ||
SectionHeaders.isDefault())
return DenseMap<StringRef, size_t>();
DenseMap<StringRef, size_t> Ret;
size_t SecNdx = 0;
StringSet<> Seen;
auto AddSection = [&](const ELFYAML::SectionHeader &Hdr) {
if (!Ret.try_emplace(Hdr.Name, ++SecNdx).second)
reportError("repeated section name: '" + Hdr.Name +
"' in the section header description");
Seen.insert(Hdr.Name);
};
if (SectionHeaders.Sections)
for (const ELFYAML::SectionHeader &Hdr : *SectionHeaders.Sections)
AddSection(Hdr);
if (SectionHeaders.Excluded)
for (const ELFYAML::SectionHeader &Hdr : *SectionHeaders.Excluded)
AddSection(Hdr);
for (const ELFYAML::Section *S : Doc.getSections()) {
// Ignore special first SHT_NULL section.
if (S == Doc.getSections().front())
continue;
if (!Seen.count(S->Name))
reportError("section '" + S->Name +
"' should be present in the 'Sections' or 'Excluded' lists");
Seen.erase(S->Name);
}
for (const auto &It : Seen)
reportError("section header contains undefined section '" + It.getKey() +
"'");
return Ret;
}
template <class ELFT> void ELFState<ELFT>::buildSectionIndex() {
// A YAML description can have an explicit section header declaration that
// allows to change the order of section headers.
DenseMap<StringRef, size_t> ReorderMap = buildSectionHeaderReorderMap();
if (HasError)
return;
// Build excluded section headers map.
std::vector<ELFYAML::Section *> Sections = Doc.getSections();
const ELFYAML::SectionHeaderTable &SectionHeaders =
Doc.getSectionHeaderTable();
if (SectionHeaders.Excluded)
for (const ELFYAML::SectionHeader &Hdr : *SectionHeaders.Excluded)
if (!ExcludedSectionHeaders.insert(Hdr.Name).second)
llvm_unreachable("buildSectionIndex() failed");
if (SectionHeaders.NoHeaders.getValueOr(false))
for (const ELFYAML::Section *S : Sections)
if (!ExcludedSectionHeaders.insert(S->Name).second)
llvm_unreachable("buildSectionIndex() failed");
size_t SecNdx = -1;
for (const ELFYAML::Section *S : Sections) {
++SecNdx;
size_t Index = ReorderMap.empty() ? SecNdx : ReorderMap.lookup(S->Name);
if (!SN2I.addName(S->Name, Index))
llvm_unreachable("buildSectionIndex() failed");
if (!ExcludedSectionHeaders.count(S->Name))
DotShStrtab.add(ELFYAML::dropUniqueSuffix(S->Name));
}
DotShStrtab.finalize();
}
template <class ELFT> void ELFState<ELFT>::buildSymbolIndexes() {
auto Build = [this](ArrayRef<ELFYAML::Symbol> V, NameToIdxMap &Map) {
for (size_t I = 0, S = V.size(); I < S; ++I) {
const ELFYAML::Symbol &Sym = V[I];
if (!Sym.Name.empty() && !Map.addName(Sym.Name, I + 1))
reportError("repeated symbol name: '" + Sym.Name + "'");
}
};
if (Doc.Symbols)
Build(*Doc.Symbols, SymN2I);
if (Doc.DynamicSymbols)
Build(*Doc.DynamicSymbols, DynSymN2I);
}
template <class ELFT> void ELFState<ELFT>::finalizeStrings() {
// Add the regular symbol names to .strtab section.
if (Doc.Symbols)
for (const ELFYAML::Symbol &Sym : *Doc.Symbols)
DotStrtab.add(ELFYAML::dropUniqueSuffix(Sym.Name));
DotStrtab.finalize();
// Add the dynamic symbol names to .dynstr section.
if (Doc.DynamicSymbols)
for (const ELFYAML::Symbol &Sym : *Doc.DynamicSymbols)
DotDynstr.add(ELFYAML::dropUniqueSuffix(Sym.Name));
// SHT_GNU_verdef and SHT_GNU_verneed sections might also
// add strings to .dynstr section.
for (const ELFYAML::Chunk *Sec : Doc.getSections()) {
if (auto VerNeed = dyn_cast<ELFYAML::VerneedSection>(Sec)) {
if (VerNeed->VerneedV) {
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)) {
if (VerDef->Entries)
for (const ELFYAML::VerdefEntry &E : *VerDef->Entries)
for (StringRef Name : E.VerNames)
DotDynstr.add(Name);
}
}
DotDynstr.finalize();
}
template <class ELFT>
bool ELFState<ELFT>::writeELF(raw_ostream &OS, ELFYAML::Object &Doc,
yaml::ErrorHandler EH, uint64_t MaxSize) {
ELFState<ELFT> State(Doc, EH);
if (State.HasError)
return false;
// 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();
State.buildSectionIndex();
State.buildSymbolIndexes();
if (State.HasError)
return false;
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 =
sizeof(Elf_Ehdr) + sizeof(Elf_Phdr) * Doc.ProgramHeaders.size();
// It is quite easy to accidentally create output with yaml2obj that is larger
// than intended, for example, due to an issue in the YAML description.
// We limit the maximum allowed output size, but also provide a command line
// option to change this limitation.
ContiguousBlobAccumulator CBA(SectionContentBeginOffset, MaxSize);
std::vector<Elf_Shdr> SHeaders;
State.initSectionHeaders(SHeaders, CBA);
// Now we can decide segment offsets.
State.setProgramHeaderLayout(PHeaders, SHeaders);
bool ReachedLimit = CBA.getOffset() > MaxSize;
if (Error E = CBA.takeLimitError()) {
// We report a custom error message instead below.
consumeError(std::move(E));
ReachedLimit = true;
}
if (ReachedLimit)
State.reportError(
"the desired output size is greater than permitted. Use the "
"--max-size option to change the limit");
if (State.HasError)
return false;
State.writeELFHeader(OS);
writeArrayData(OS, makeArrayRef(PHeaders));
const ELFYAML::SectionHeaderTable &SHT = Doc.getSectionHeaderTable();
if (!SHT.NoHeaders.getValueOr(false))
CBA.updateDataAt(*SHT.Offset, SHeaders.data(),
SHT.getNumHeaders(SHeaders.size()) * sizeof(Elf_Shdr));
CBA.writeBlobToStream(OS);
return true;
}
namespace llvm {
namespace yaml {
bool yaml2elf(llvm::ELFYAML::Object &Doc, raw_ostream &Out, ErrorHandler EH,
uint64_t MaxSize) {
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, EH, MaxSize);
return ELFState<object::ELF64BE>::writeELF(Out, Doc, EH, MaxSize);
}
if (IsLE)
return ELFState<object::ELF32LE>::writeELF(Out, Doc, EH, MaxSize);
return ELFState<object::ELF32BE>::writeELF(Out, Doc, EH, MaxSize);
}
} // namespace yaml
} // namespace llvm
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