RPCS3/archived-llvm
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm.git synced 2026-01-31 01:25:19 +01:00
Code Issues Packages Projects Releases Wiki Activity
Files
38f2fbe008c197076929dddce618c2f00a626cf2
archived-llvm/tools/yaml2obj/yaml2elf.cpp
Dave Lee 9a5be1f566 Reapply: Allow yaml2obj to order implicit sections for ELF 
Summary:
This change allows yaml input to control the order of implicitly added sections
(`.symtab`, `.strtab`, `.shstrtab`). The order is controlled by adding a
placeholder section of the given name to the Sections field.

This change is to support changes in D39582, where it is desirable to control
the location of the `.dynsym` section.

This reapplied version fixes:
  1. use of a function call within an assert
  2. failing lld test which has an unnamed section
  3. incorrect section count when given an unnamed section

Additionally, one more test to cover the unnamed section failure.

Reviewers: compnerd, jakehehrlich

Reviewed By: jakehehrlich

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D39749

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317789 91177308-0d34-0410-b5e6-96231b3b80d8
2017-11-09 14:53:43 +00:00

677 lines
24 KiB
C++
Raw Blame History

//===- yaml2elf - Convert YAML to a ELF object file -----------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// \brief The ELF component of yaml2obj.
///
//===----------------------------------------------------------------------===//
#include "yaml2obj.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/MC/StringTableBuilder.h"
#include "llvm/Object/ELFObjectFile.h"
#include "llvm/ObjectYAML/ELFYAML.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/YAMLTraits.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
// This class is used to build up a contiguous binary blob while keeping
// track of an offset in the output (which notionally begins at
// `InitialOffset`).
namespace {
class ContiguousBlobAccumulator {
const uint64_t InitialOffset;
SmallVector<char, 128> Buf;
raw_svector_ostream OS;
/// \returns The new offset.
uint64_t padToAlignment(unsigned Align) {
if (Align == 0)
Align = 1;
uint64_t CurrentOffset = InitialOffset + OS.tell();
uint64_t AlignedOffset = alignTo(CurrentOffset, Align);
for (; CurrentOffset != AlignedOffset; ++CurrentOffset)
OS.write('\0');
return AlignedOffset; // == CurrentOffset;
}
public:
ContiguousBlobAccumulator(uint64_t InitialOffset_)
: InitialOffset(InitialOffset_), Buf(), OS(Buf) {}
template <class Integer>
raw_ostream &getOSAndAlignedOffset(Integer &Offset, unsigned Align) {
Offset = padToAlignment(Align);
return OS;
}
void writeBlobToStream(raw_ostream &Out) { Out << OS.str(); }
};
} // end anonymous namespace
// Used to keep track of section and symbol names, so that in the YAML file
// sections and symbols can be referenced by name instead of by index.
namespace {
class NameToIdxMap {
StringMap<int> Map;
public:
/// \returns true if name is already present in the map.
bool addName(StringRef Name, unsigned i) {
return !Map.insert(std::make_pair(Name, (int)i)).second;
}
/// \returns true if name is not present in the map
bool lookup(StringRef Name, unsigned &Idx) const {
StringMap<int>::const_iterator I = Map.find(Name);
if (I == Map.end())
return true;
Idx = I->getValue();
return false;
}
/// asserts if name is not present in the map
unsigned get(StringRef Name) const {
unsigned Idx = 0;
auto missing = lookup(Name, Idx);
(void)missing;
assert(!missing && "Expected section not found in index");
return Idx;
}
unsigned size() const { return Map.size(); }
};
} // end anonymous namespace
template <class T>
static size_t arrayDataSize(ArrayRef<T> A) {
return A.size() * sizeof(T);
}
template <class T>
static void writeArrayData(raw_ostream &OS, ArrayRef<T> A) {
OS.write((const char *)A.data(), arrayDataSize(A));
}
template <class T>
static void zero(T &Obj) {
memset(&Obj, 0, sizeof(Obj));
}
namespace {
/// \brief "Single point of truth" for the ELF file construction.
/// TODO: This class still has a ways to go before it is truly a "single
/// point of truth".
template <class ELFT>
class ELFState {
typedef typename object::ELFFile<ELFT>::Elf_Ehdr Elf_Ehdr;
typedef typename object::ELFFile<ELFT>::Elf_Phdr Elf_Phdr;
typedef typename object::ELFFile<ELFT>::Elf_Shdr Elf_Shdr;
typedef typename object::ELFFile<ELFT>::Elf_Sym Elf_Sym;
typedef typename object::ELFFile<ELFT>::Elf_Rel Elf_Rel;
typedef typename object::ELFFile<ELFT>::Elf_Rela Elf_Rela;
/// \brief The future ".strtab" section.
StringTableBuilder DotStrtab{StringTableBuilder::ELF};
/// \brief The future ".shstrtab" section.
StringTableBuilder DotShStrtab{StringTableBuilder::ELF};
NameToIdxMap SN2I;
NameToIdxMap SymN2I;
const ELFYAML::Object &Doc;
bool buildSectionIndex();
bool buildSymbolIndex(std::size_t &StartIndex,
const std::vector<ELFYAML::Symbol> &Symbols);
void initELFHeader(Elf_Ehdr &Header);
void initProgramHeaders(std::vector<Elf_Phdr> &PHeaders);
bool initSectionHeaders(std::vector<Elf_Shdr> &SHeaders,
ContiguousBlobAccumulator &CBA);
void initSymtabSectionHeader(Elf_Shdr &SHeader,
ContiguousBlobAccumulator &CBA);
void initStrtabSectionHeader(Elf_Shdr &SHeader, StringRef Name,
StringTableBuilder &STB,
ContiguousBlobAccumulator &CBA);
void setProgramHeaderLayout(std::vector<Elf_Phdr> &PHeaders,
std::vector<Elf_Shdr> &SHeaders);
void addSymbols(const std::vector<ELFYAML::Symbol> &Symbols,
std::vector<Elf_Sym> &Syms, unsigned SymbolBinding);
void writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::RawContentSection &Section,
ContiguousBlobAccumulator &CBA);
bool writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::RelocationSection &Section,
ContiguousBlobAccumulator &CBA);
bool writeSectionContent(Elf_Shdr &SHeader, const ELFYAML::Group &Group,
ContiguousBlobAccumulator &CBA);
bool writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::MipsABIFlags &Section,
ContiguousBlobAccumulator &CBA);
// - SHT_NULL entry (placed first, i.e. 0'th entry)
// - symbol table (.symtab) (defaults to third to last)
// - string table (.strtab) (defaults to second to last)
// - section header string table (.shstrtab) (defaults to last)
unsigned getDotSymTabSecNo() const { return SN2I.get(".symtab"); }
unsigned getDotStrTabSecNo() const { return SN2I.get(".strtab"); }
unsigned getDotShStrTabSecNo() const { return SN2I.get(".shstrtab"); }
unsigned getSectionCount() const { return SN2I.size() + 1; }
ELFState(const ELFYAML::Object &D) : Doc(D) {}
public:
static int writeELF(raw_ostream &OS, const ELFYAML::Object &Doc);
};
static const char * const ImplicitSecNames[] = {".symtab", ".strtab", ".shstrtab"};
} // end anonymous namespace
template <class ELFT>
void ELFState<ELFT>::initELFHeader(Elf_Ehdr &Header) {
using namespace llvm::ELF;
zero(Header);
Header.e_ident[EI_MAG0] = 0x7f;
Header.e_ident[EI_MAG1] = 'E';
Header.e_ident[EI_MAG2] = 'L';
Header.e_ident[EI_MAG3] = 'F';
Header.e_ident[EI_CLASS] = ELFT::Is64Bits ? ELFCLASS64 : ELFCLASS32;
bool IsLittleEndian = ELFT::TargetEndianness == support::little;
Header.e_ident[EI_DATA] = IsLittleEndian ? ELFDATA2LSB : ELFDATA2MSB;
Header.e_ident[EI_VERSION] = EV_CURRENT;
Header.e_ident[EI_OSABI] = Doc.Header.OSABI;
Header.e_ident[EI_ABIVERSION] = 0;
Header.e_type = Doc.Header.Type;
Header.e_machine = Doc.Header.Machine;
Header.e_version = EV_CURRENT;
Header.e_entry = Doc.Header.Entry;
Header.e_phoff = sizeof(Header);
Header.e_flags = Doc.Header.Flags;
Header.e_ehsize = sizeof(Elf_Ehdr);
Header.e_phentsize = sizeof(Elf_Phdr);
Header.e_phnum = Doc.ProgramHeaders.size();
Header.e_shentsize = sizeof(Elf_Shdr);
// Immediately following the ELF header and program headers.
Header.e_shoff =
sizeof(Header) + sizeof(Elf_Phdr) * Doc.ProgramHeaders.size();
Header.e_shnum = getSectionCount();
Header.e_shstrndx = getDotShStrTabSecNo();
}
template <class ELFT>
void ELFState<ELFT>::initProgramHeaders(std::vector<Elf_Phdr> &PHeaders) {
for (const auto &YamlPhdr : Doc.ProgramHeaders) {
Elf_Phdr Phdr;
Phdr.p_type = YamlPhdr.Type;
Phdr.p_flags = YamlPhdr.Flags;
Phdr.p_vaddr = YamlPhdr.VAddr;
Phdr.p_paddr = YamlPhdr.PAddr;
PHeaders.push_back(Phdr);
}
}
template <class ELFT>
bool 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.
Elf_Shdr SHeader;
zero(SHeader);
SHeaders.push_back(SHeader);
for (const auto &Sec : Doc.Sections) {
zero(SHeader);
SHeader.sh_name = DotShStrtab.getOffset(Sec->Name);
SHeader.sh_type = Sec->Type;
SHeader.sh_flags = Sec->Flags;
SHeader.sh_addr = Sec->Address;
SHeader.sh_addralign = Sec->AddressAlign;
if (!Sec->Link.empty()) {
unsigned Index;
if (SN2I.lookup(Sec->Link, Index)) {
errs() << "error: Unknown section referenced: '" << Sec->Link
<< "' at YAML section '" << Sec->Name << "'.\n";
return false;
}
SHeader.sh_link = Index;
}
if (auto S = dyn_cast<ELFYAML::RawContentSection>(Sec.get()))
writeSectionContent(SHeader, *S, CBA);
else if (auto S = dyn_cast<ELFYAML::RelocationSection>(Sec.get())) {
if (S->Link.empty())
// For relocation section set link to .symtab by default.
SHeader.sh_link = getDotSymTabSecNo();
unsigned Index;
if (SN2I.lookup(S->Info, Index)) {
if (S->Info.getAsInteger(0, Index)) {
errs() << "error: Unknown section referenced: '" << S->Info
<< "' at YAML section '" << S->Name << "'.\n";
return false;
}
}
SHeader.sh_info = Index;
if (!writeSectionContent(SHeader, *S, CBA))
return false;
} else if (auto S = dyn_cast<ELFYAML::Group>(Sec.get())) {
unsigned SymIdx;
if (SymN2I.lookup(S->Info, SymIdx)) {
errs() << "error: Unknown symbol referenced: '" << S->Info
<< "' at YAML section '" << S->Name << "'.\n";
return false;
}
SHeader.sh_info = SymIdx;
if (!writeSectionContent(SHeader, *S, CBA))
return false;
} else if (auto S = dyn_cast<ELFYAML::MipsABIFlags>(Sec.get())) {
if (!writeSectionContent(SHeader, *S, CBA))
return false;
} else if (auto S = dyn_cast<ELFYAML::NoBitsSection>(Sec.get())) {
SHeader.sh_entsize = 0;
SHeader.sh_size = S->Size;
// SHT_NOBITS section does not have content
// so just to setup the section offset.
CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
} else
llvm_unreachable("Unknown section type");
SHeaders.push_back(SHeader);
}
return true;
}
template <class ELFT>
void ELFState<ELFT>::initSymtabSectionHeader(Elf_Shdr &SHeader,
ContiguousBlobAccumulator &CBA) {
zero(SHeader);
SHeader.sh_name = DotShStrtab.getOffset(".symtab");
SHeader.sh_type = ELF::SHT_SYMTAB;
SHeader.sh_link = getDotStrTabSecNo();
// One greater than symbol table index of the last local symbol.
SHeader.sh_info = Doc.Symbols.Local.size() + 1;
SHeader.sh_entsize = sizeof(Elf_Sym);
SHeader.sh_addralign = 8;
std::vector<Elf_Sym> Syms;
{
// Ensure STN_UNDEF is present
Elf_Sym Sym;
zero(Sym);
Syms.push_back(Sym);
}
// Add symbol names to .strtab.
for (const auto &Sym : Doc.Symbols.Local)
DotStrtab.add(Sym.Name);
for (const auto &Sym : Doc.Symbols.Global)
DotStrtab.add(Sym.Name);
for (const auto &Sym : Doc.Symbols.Weak)
DotStrtab.add(Sym.Name);
DotStrtab.finalize();
addSymbols(Doc.Symbols.Local, Syms, ELF::STB_LOCAL);
addSymbols(Doc.Symbols.Global, Syms, ELF::STB_GLOBAL);
addSymbols(Doc.Symbols.Weak, Syms, ELF::STB_WEAK);
writeArrayData(
CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign),
makeArrayRef(Syms));
SHeader.sh_size = arrayDataSize(makeArrayRef(Syms));
}
template <class ELFT>
void ELFState<ELFT>::initStrtabSectionHeader(Elf_Shdr &SHeader, StringRef Name,
StringTableBuilder &STB,
ContiguousBlobAccumulator &CBA) {
zero(SHeader);
SHeader.sh_name = DotShStrtab.getOffset(Name);
SHeader.sh_type = ELF::SHT_STRTAB;
STB.write(CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign));
SHeader.sh_size = STB.getSize();
SHeader.sh_addralign = 1;
}
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) {
auto &PHeader = PHeaders[PhdrIdx++];
if (YamlPhdr.Sections.size())
PHeader.p_offset = UINT32_MAX;
else
PHeader.p_offset = 0;
// Find the minimum offset for the program header.
for (auto SecName : YamlPhdr.Sections) {
uint32_t Index = 0;
SN2I.lookup(SecName.Section, Index);
const auto &SHeader = SHeaders[Index];
PHeader.p_offset = std::min(PHeader.p_offset, SHeader.sh_offset);
}
// Find the maximum offset of the end of a section in order to set p_filesz.
PHeader.p_filesz = 0;
for (auto SecName : YamlPhdr.Sections) {
uint32_t Index = 0;
SN2I.lookup(SecName.Section, Index);
const auto &SHeader = SHeaders[Index];
uint64_t EndOfSection;
if (SHeader.sh_type == llvm::ELF::SHT_NOBITS)
EndOfSection = SHeader.sh_offset;
else
EndOfSection = SHeader.sh_offset + SHeader.sh_size;
uint64_t EndOfSegment = PHeader.p_offset + PHeader.p_filesz;
EndOfSegment = std::max(EndOfSegment, EndOfSection);
PHeader.p_filesz = EndOfSegment - PHeader.p_offset;
}
// Find the memory size by adding the size of sections at the end of the
// segment. These should be empty (size of zero) and NOBITS sections.
PHeader.p_memsz = PHeader.p_filesz;
for (auto SecName : YamlPhdr.Sections) {
uint32_t Index = 0;
SN2I.lookup(SecName.Section, Index);
const auto &SHeader = SHeaders[Index];
if (SHeader.sh_offset == PHeader.p_offset + PHeader.p_filesz)
PHeader.p_memsz += SHeader.sh_size;
}
// Set the alignment of the segment to be the same as the maximum alignment
// of the sections with the same offset so that by default the segment
// has a valid and sensible alignment.
if (YamlPhdr.Align) {
PHeader.p_align = *YamlPhdr.Align;
} else {
PHeader.p_align = 1;
for (auto SecName : YamlPhdr.Sections) {
uint32_t Index = 0;
SN2I.lookup(SecName.Section, Index);
const auto &SHeader = SHeaders[Index];
if (SHeader.sh_offset == PHeader.p_offset)
PHeader.p_align = std::max(PHeader.p_align, SHeader.sh_addralign);
}
}
}
}
template <class ELFT>
void ELFState<ELFT>::addSymbols(const std::vector<ELFYAML::Symbol> &Symbols,
std::vector<Elf_Sym> &Syms,
unsigned SymbolBinding) {
for (const auto &Sym : Symbols) {
Elf_Sym Symbol;
zero(Symbol);
if (!Sym.Name.empty())
Symbol.st_name = DotStrtab.getOffset(Sym.Name);
Symbol.setBindingAndType(SymbolBinding, Sym.Type);
if (!Sym.Section.empty()) {
unsigned Index;
if (SN2I.lookup(Sym.Section, Index)) {
errs() << "error: Unknown section referenced: '" << Sym.Section
<< "' by YAML symbol " << Sym.Name << ".\n";
exit(1);
}
Symbol.st_shndx = Index;
} else if (Sym.Index) {
Symbol.st_shndx = *Sym.Index;
}
// else Symbol.st_shndex == SHN_UNDEF (== 0), since it was zero'd earlier.
Symbol.st_value = Sym.Value;
Symbol.st_other = Sym.Other;
Symbol.st_size = Sym.Size;
Syms.push_back(Symbol);
}
}
template <class ELFT>
void
ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::RawContentSection &Section,
ContiguousBlobAccumulator &CBA) {
assert(Section.Size >= Section.Content.binary_size() &&
"Section size and section content are inconsistent");
raw_ostream &OS =
CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
Section.Content.writeAsBinary(OS);
for (auto i = Section.Content.binary_size(); i < Section.Size; ++i)
OS.write(0);
SHeader.sh_entsize = 0;
SHeader.sh_size = Section.Size;
}
static bool isMips64EL(const ELFYAML::Object &Doc) {
return Doc.Header.Machine == ELFYAML::ELF_EM(llvm::ELF::EM_MIPS) &&
Doc.Header.Class == ELFYAML::ELF_ELFCLASS(ELF::ELFCLASS64) &&
Doc.Header.Data == ELFYAML::ELF_ELFDATA(ELF::ELFDATA2LSB);
}
template <class ELFT>
bool
ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::RelocationSection &Section,
ContiguousBlobAccumulator &CBA) {
assert((Section.Type == llvm::ELF::SHT_REL ||
Section.Type == llvm::ELF::SHT_RELA) &&
"Section type is not SHT_REL nor SHT_RELA");
bool IsRela = Section.Type == llvm::ELF::SHT_RELA;
SHeader.sh_entsize = IsRela ? sizeof(Elf_Rela) : sizeof(Elf_Rel);
SHeader.sh_size = SHeader.sh_entsize * Section.Relocations.size();
auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
for (const auto &Rel : Section.Relocations) {
unsigned SymIdx = 0;
// Some special relocation, R_ARM_v4BX for instance, does not have
// an external reference. So it ignores the return value of lookup()
// here.
if (Rel.Symbol)
SymN2I.lookup(*Rel.Symbol, SymIdx);
if (IsRela) {
Elf_Rela REntry;
zero(REntry);
REntry.r_offset = Rel.Offset;
REntry.r_addend = Rel.Addend;
REntry.setSymbolAndType(SymIdx, Rel.Type, isMips64EL(Doc));
OS.write((const char *)&REntry, sizeof(REntry));
} else {
Elf_Rel REntry;
zero(REntry);
REntry.r_offset = Rel.Offset;
REntry.setSymbolAndType(SymIdx, Rel.Type, isMips64EL(Doc));
OS.write((const char *)&REntry, sizeof(REntry));
}
}
return true;
}
template <class ELFT>
bool ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::Group &Section,
ContiguousBlobAccumulator &CBA) {
typedef typename object::ELFFile<ELFT>::Elf_Word Elf_Word;
assert(Section.Type == llvm::ELF::SHT_GROUP &&
"Section type is not SHT_GROUP");
SHeader.sh_entsize = sizeof(Elf_Word);
SHeader.sh_size = SHeader.sh_entsize * Section.Members.size();
auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
for (auto member : Section.Members) {
Elf_Word SIdx;
unsigned int sectionIndex = 0;
if (member.sectionNameOrType == "GRP_COMDAT")
sectionIndex = llvm::ELF::GRP_COMDAT;
else if (SN2I.lookup(member.sectionNameOrType, sectionIndex)) {
errs() << "error: Unknown section referenced: '"
<< member.sectionNameOrType << "' at YAML section' "
<< Section.Name << "\n";
return false;
}
SIdx = sectionIndex;
OS.write((const char *)&SIdx, sizeof(SIdx));
}
return true;
}
template <class ELFT>
bool ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
const ELFYAML::MipsABIFlags &Section,
ContiguousBlobAccumulator &CBA) {
assert(Section.Type == llvm::ELF::SHT_MIPS_ABIFLAGS &&
"Section type is not SHT_MIPS_ABIFLAGS");
object::Elf_Mips_ABIFlags<ELFT> Flags;
zero(Flags);
SHeader.sh_entsize = sizeof(Flags);
SHeader.sh_size = SHeader.sh_entsize;
auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
Flags.version = Section.Version;
Flags.isa_level = Section.ISALevel;
Flags.isa_rev = Section.ISARevision;
Flags.gpr_size = Section.GPRSize;
Flags.cpr1_size = Section.CPR1Size;
Flags.cpr2_size = Section.CPR2Size;
Flags.fp_abi = Section.FpABI;
Flags.isa_ext = Section.ISAExtension;
Flags.ases = Section.ASEs;
Flags.flags1 = Section.Flags1;
Flags.flags2 = Section.Flags2;
OS.write((const char *)&Flags, sizeof(Flags));
return true;
}
template <class ELFT> bool ELFState<ELFT>::buildSectionIndex() {
for (unsigned i = 0, e = Doc.Sections.size(); i != e; ++i) {
StringRef Name = Doc.Sections[i]->Name;
DotShStrtab.add(Name);
// "+ 1" to take into account the SHT_NULL entry.
if (SN2I.addName(Name, i + 1)) {
errs() << "error: Repeated section name: '" << Name
<< "' at YAML section number " << i << ".\n";
return false;
}
}
auto SecNo = 1 + Doc.Sections.size();
// Add special sections after input sections, if necessary.
for (const auto &Name : ImplicitSecNames)
if (!SN2I.addName(Name, SecNo)) {
// Account for this section, since it wasn't in the Doc
++SecNo;
DotShStrtab.add(Name);
}
DotShStrtab.finalize();
return true;
}
template <class ELFT>
bool
ELFState<ELFT>::buildSymbolIndex(std::size_t &StartIndex,
const std::vector<ELFYAML::Symbol> &Symbols) {
for (const auto &Sym : Symbols) {
++StartIndex;
if (Sym.Name.empty())
continue;
if (SymN2I.addName(Sym.Name, StartIndex)) {
errs() << "error: Repeated symbol name: '" << Sym.Name << "'.\n";
return false;
}
}
return true;
}
template <class ELFT>
int ELFState<ELFT>::writeELF(raw_ostream &OS, const ELFYAML::Object &Doc) {
ELFState<ELFT> State(Doc);
if (!State.buildSectionIndex())
return 1;
std::size_t StartSymIndex = 0;
if (!State.buildSymbolIndex(StartSymIndex, Doc.Symbols.Local) ||
!State.buildSymbolIndex(StartSymIndex, Doc.Symbols.Global) ||
!State.buildSymbolIndex(StartSymIndex, Doc.Symbols.Weak))
return 1;
Elf_Ehdr Header;
State.initELFHeader(Header);
// TODO: Flesh out section header support.
std::vector<Elf_Phdr> PHeaders;
State.initProgramHeaders(PHeaders);
// XXX: This offset is tightly coupled with the order that we write
// things to `OS`.
const size_t SectionContentBeginOffset = Header.e_ehsize +
Header.e_phentsize * Header.e_phnum +
Header.e_shentsize * Header.e_shnum;
ContiguousBlobAccumulator CBA(SectionContentBeginOffset);
std::vector<Elf_Shdr> SHeaders;
if(!State.initSectionHeaders(SHeaders, CBA))
return 1;
// Populate SHeaders with implicit sections not present in the Doc
for (const auto &Name : ImplicitSecNames)
if (State.SN2I.get(Name) >= SHeaders.size())
SHeaders.push_back({});
// Initialize the implicit sections
auto Index = State.SN2I.get(".symtab");
State.initSymtabSectionHeader(SHeaders[Index], CBA);
Index = State.SN2I.get(".strtab");
State.initStrtabSectionHeader(SHeaders[Index], ".strtab", State.DotStrtab, CBA);
Index = State.SN2I.get(".shstrtab");
State.initStrtabSectionHeader(SHeaders[Index], ".shstrtab", State.DotShStrtab, CBA);
// Now we can decide segment offsets
State.setProgramHeaderLayout(PHeaders, SHeaders);
OS.write((const char *)&Header, sizeof(Header));
writeArrayData(OS, makeArrayRef(PHeaders));
writeArrayData(OS, makeArrayRef(SHeaders));
CBA.writeBlobToStream(OS);
return 0;
}
static bool is64Bit(const ELFYAML::Object &Doc) {
return Doc.Header.Class == ELFYAML::ELF_ELFCLASS(ELF::ELFCLASS64);
}
static bool isLittleEndian(const ELFYAML::Object &Doc) {
return Doc.Header.Data == ELFYAML::ELF_ELFDATA(ELF::ELFDATA2LSB);
}
int yaml2elf(llvm::ELFYAML::Object &Doc, raw_ostream &Out) {
using object::ELFType;
typedef ELFType<support::little, true> LE64;
typedef ELFType<support::big, true> BE64;
typedef ELFType<support::little, false> LE32;
typedef ELFType<support::big, false> BE32;
if (is64Bit(Doc)) {
if (isLittleEndian(Doc))
return ELFState<LE64>::writeELF(Out, Doc);
else
return ELFState<BE64>::writeELF(Out, Doc);
} else {
if (isLittleEndian(Doc))
return ELFState<LE32>::writeELF(Out, Doc);
else
return ELFState<BE32>::writeELF(Out, Doc);
}
}
Reference in New Issue View Git Blame Copy Permalink