// to deduplicate suffixes. std::map<> with a custom comparator is likely
// to be the simplest implementation, but a suffix trie could be more
// suitable for the job.
+namespace {
class StringTableBuilder {
/// \brief Indices of strings currently present in `Buf`.
StringMap<unsigned> StringIndices;
OS.write(Buf.data(), Buf.size());
}
};
+} // end anonymous namespace
// 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) {
+ uint64_t CurrentOffset = InitialOffset + OS.tell();
+ uint64_t AlignedOffset = RoundUpToAlignment(CurrentOffset, Align);
+ for (; CurrentOffset != AlignedOffset; ++CurrentOffset)
+ OS.write('\0');
+ return AlignedOffset; // == CurrentOffset;
+ }
+
public:
- ContiguousBlobAccumulator(uint64_t InitialOffset_, SmallVectorImpl<char> &Buf)
- : InitialOffset(InitialOffset_), OS(Buf) {}
- raw_ostream &getOS() { return OS; }
- uint64_t currentOffset() const { return InitialOffset + OS.tell(); }
+ ContiguousBlobAccumulator(uint64_t InitialOffset_)
+ : InitialOffset(InitialOffset_), Buf(), OS(Buf) {}
+ template <class Integer>
+ raw_ostream &getOSAndAlignedOffset(Integer &Offset, unsigned Align = 16) {
+ Offset = padToAlignment(Align);
+ return OS;
+ }
void writeBlobToStream(raw_ostream &Out) { Out << OS.str(); }
};
+} // end anonymous namespace
+
+// Used to keep track of section names, so that in the YAML file sections
+// can be referenced by name instead of by index.
+namespace {
+class SectionNameToIdxMap {
+ StringMap<int> Map;
+public:
+ /// \returns true if name is already present in the map.
+ bool addName(StringRef SecName, unsigned i) {
+ StringMapEntry<int> &Entry = Map.GetOrCreateValue(SecName, -1);
+ if (Entry.getValue() != -1)
+ return true;
+ Entry.setValue((int)i);
+ return false;
+ }
+ /// \returns true if name is not present in the map
+ bool lookupSection(StringRef SecName, unsigned &Idx) const {
+ StringMap<int>::const_iterator I = Map.find(SecName);
+ if (I == Map.end())
+ return true;
+ Idx = I->getValue();
+ return false;
+ }
+};
+} // end anonymous namespace
template <class T>
static size_t vectorDataSize(const std::vector<T> &Vec) {
memset(&Obj, 0, sizeof(Obj));
}
+/// \brief Create a string table in `SHeader`, which we assume is already
+/// zero'd.
+template <class Elf_Shdr>
+static void createStringTableSectionHeader(Elf_Shdr &SHeader,
+ StringTableBuilder &STB,
+ ContiguousBlobAccumulator &CBA) {
+ SHeader.sh_type = ELF::SHT_STRTAB;
+ STB.writeToStream(CBA.getOSAndAlignedOffset(SHeader.sh_offset));
+ SHeader.sh_size = STB.size();
+ SHeader.sh_addralign = 1;
+}
+
+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>
-static void writeELF(raw_ostream &OS, const ELFYAML::Object &Doc) {
+class ELFState {
+ /// \brief The future ".strtab" section.
+ StringTableBuilder DotStrtab;
+ /// \brief The section number of the ".strtab" section.
+ unsigned DotStrtabSecNo;
+ /// \brief The accumulated contents of all sections so far.
+ ContiguousBlobAccumulator &SectionContentAccum;
+ typedef typename object::ELFObjectFile<ELFT>::Elf_Ehdr Elf_Ehdr;
+ /// \brief The ELF file header.
+ Elf_Ehdr &Header;
+
+ SectionNameToIdxMap &SN2I;
+
+public:
+
+ ELFState(Elf_Ehdr &Header_, ContiguousBlobAccumulator &Accum,
+ unsigned DotStrtabSecNo_, SectionNameToIdxMap &SN2I_)
+ : DotStrtab(), DotStrtabSecNo(DotStrtabSecNo_),
+ SectionContentAccum(Accum), Header(Header_), SN2I(SN2I_) {}
+
+ unsigned getDotStrTabSecNo() const { return DotStrtabSecNo; }
+ StringTableBuilder &getStringTable() { return DotStrtab; }
+ ContiguousBlobAccumulator &getSectionContentAccum() {
+ return SectionContentAccum;
+ }
+ SectionNameToIdxMap &getSN2I() { return SN2I; }
+};
+} // end anonymous namespace
+
+// FIXME: At this point it is fairly clear that we need to refactor these
+// static functions into methods of a class sharing some typedefs. These
+// ELF type names are insane.
+template <class ELFT>
+static void
+addSymbols(const std::vector<ELFYAML::Symbol> &Symbols, ELFState<ELFT> &State,
+ std::vector<typename object::ELFObjectFile<ELFT>::Elf_Sym> &Syms,
+ unsigned SymbolBinding) {
+ typedef typename object::ELFObjectFile<ELFT>::Elf_Sym Elf_Sym;
+ for (unsigned i = 0, e = Symbols.size(); i != e; ++i) {
+ const ELFYAML::Symbol &Sym = Symbols[i];
+ Elf_Sym Symbol;
+ zero(Symbol);
+ if (!Sym.Name.empty())
+ Symbol.st_name = State.getStringTable().addString(Sym.Name);
+ Symbol.setBindingAndType(SymbolBinding, Sym.Type);
+ if (!Sym.Section.empty()) {
+ unsigned Index;
+ if (State.getSN2I().lookupSection(Sym.Section, Index)) {
+ errs() << "error: Unknown section referenced: '" << Sym.Section
+ << "' by YAML symbol " << Sym.Name << ".\n";
+ exit(1);
+ }
+ Symbol.st_shndx = Index;
+ } // else Symbol.st_shndex == SHN_UNDEF (== 0), since it was zero'd earlier.
+ Symbol.st_value = Sym.Value;
+ Symbol.st_size = Sym.Size;
+ Syms.push_back(Symbol);
+ }
+}
+
+template <class ELFT>
+static void handleSymtabSectionHeader(
+ const ELFYAML::LocalGlobalWeakSymbols &Symbols, ELFState<ELFT> &State,
+ typename object::ELFObjectFile<ELFT>::Elf_Shdr &SHeader) {
+
+ typedef typename object::ELFObjectFile<ELFT>::Elf_Sym Elf_Sym;
+ // TODO: Ensure that a manually specified `Link` field is diagnosed as an
+ // error for SHT_SYMTAB.
+ SHeader.sh_link = State.getDotStrTabSecNo();
+ // One greater than symbol table index of the last local symbol.
+ SHeader.sh_info = Symbols.Local.size() + 1;
+ SHeader.sh_entsize = sizeof(Elf_Sym);
+
+ std::vector<Elf_Sym> Syms;
+ {
+ // Ensure STN_UNDEF is present
+ Elf_Sym Sym;
+ zero(Sym);
+ Syms.push_back(Sym);
+ }
+ addSymbols(Symbols.Local, State, Syms, ELF::STB_LOCAL);
+ addSymbols(Symbols.Global, State, Syms, ELF::STB_GLOBAL);
+ addSymbols(Symbols.Weak, State, Syms, ELF::STB_WEAK);
+
+ ContiguousBlobAccumulator &CBA = State.getSectionContentAccum();
+ writeVectorData(CBA.getOSAndAlignedOffset(SHeader.sh_offset), Syms);
+ SHeader.sh_size = vectorDataSize(Syms);
+}
+
+template <class ELFT>
+static int writeELF(raw_ostream &OS, const ELFYAML::Object &Doc) {
using namespace llvm::ELF;
- using namespace llvm::object;
- typedef typename ELFObjectFile<ELFT>::Elf_Ehdr Elf_Ehdr;
- typedef typename ELFObjectFile<ELFT>::Elf_Shdr Elf_Shdr;
+ typedef typename object::ELFObjectFile<ELFT>::Elf_Ehdr Elf_Ehdr;
+ typedef typename object::ELFObjectFile<ELFT>::Elf_Shdr Elf_Shdr;
const ELFYAML::FileHeader &Hdr = Doc.Header;
bool IsLittleEndian = ELFT::TargetEndianness == support::little;
Header.e_ident[EI_DATA] = IsLittleEndian ? ELFDATA2LSB : ELFDATA2MSB;
Header.e_ident[EI_VERSION] = EV_CURRENT;
- // TODO: Implement ELF_ELFOSABI enum.
- Header.e_ident[EI_OSABI] = ELFOSABI_NONE;
- // TODO: Implement ELF_ABIVERSION enum.
+ Header.e_ident[EI_OSABI] = Hdr.OSABI;
Header.e_ident[EI_ABIVERSION] = 0;
Header.e_type = Hdr.Type;
Header.e_machine = Hdr.Machine;
Header.e_shentsize = sizeof(Elf_Shdr);
// Immediately following the ELF header.
Header.e_shoff = sizeof(Header);
- std::vector<ELFYAML::Section> Sections = Doc.Sections;
- if (Sections.empty() || Sections.front().Type != SHT_NULL) {
- ELFYAML::Section S;
- S.Type = SHT_NULL;
- zero(S.Flags);
- Sections.insert(Sections.begin(), S);
- }
- // "+ 1" for string table.
- Header.e_shnum = Sections.size() + 1;
+ const std::vector<ELFYAML::Section> &Sections = Doc.Sections;
+ // "+ 3" for
+ // - SHT_NULL entry (placed first, i.e. 0'th entry)
+ // - string table (.strtab) (placed second to last)
+ // - section header string table. (placed last)
+ Header.e_shnum = Sections.size() + 3;
// Place section header string table last.
- Header.e_shstrndx = Sections.size();
+ Header.e_shstrndx = Header.e_shnum - 1;
+ const unsigned DotStrtabSecNo = Header.e_shnum - 2;
- StringTableBuilder StrTab;
- SmallVector<char, 128> Buf;
// XXX: This offset is tightly coupled with the order that we write
// things to `OS`.
const size_t SectionContentBeginOffset =
Header.e_ehsize + Header.e_shentsize * Header.e_shnum;
- ContiguousBlobAccumulator CBA(SectionContentBeginOffset, Buf);
+ ContiguousBlobAccumulator CBA(SectionContentBeginOffset);
+ SectionNameToIdxMap SN2I;
+ for (unsigned i = 0, e = Sections.size(); i != e; ++i) {
+ StringRef Name = Sections[i].Name;
+ if (Name.empty())
+ continue;
+ // "+ 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 1;
+ }
+ }
+
+ ELFState<ELFT> State(Header, CBA, DotStrtabSecNo, SN2I);
+
+ StringTableBuilder SHStrTab;
std::vector<Elf_Shdr> SHeaders;
+ {
+ // Ensure SHN_UNDEF entry is present. An all-zero section header is a
+ // valid SHN_UNDEF entry since SHT_NULL == 0.
+ Elf_Shdr SHdr;
+ zero(SHdr);
+ SHeaders.push_back(SHdr);
+ }
for (unsigned i = 0, e = Sections.size(); i != e; ++i) {
const ELFYAML::Section &Sec = Sections[i];
Elf_Shdr SHeader;
zero(SHeader);
- SHeader.sh_name = StrTab.addString(Sec.Name);
+ SHeader.sh_name = SHStrTab.addString(Sec.Name);
SHeader.sh_type = Sec.Type;
SHeader.sh_flags = Sec.Flags;
SHeader.sh_addr = Sec.Address;
- SHeader.sh_offset = CBA.currentOffset();
+ Sec.Content.writeAsBinary(CBA.getOSAndAlignedOffset(SHeader.sh_offset));
SHeader.sh_size = Sec.Content.binary_size();
- Sec.Content.writeAsBinary(CBA.getOS());
- SHeader.sh_link = 0;
+ if (!Sec.Link.empty()) {
+ unsigned Index;
+ if (SN2I.lookupSection(Sec.Link, Index)) {
+ errs() << "error: Unknown section referenced: '" << Sec.Link
+ << "' at YAML section number " << i << ".\n";
+ return 1;
+ }
+ SHeader.sh_link = Index;
+ }
SHeader.sh_info = 0;
- SHeader.sh_addralign = 1;
+ SHeader.sh_addralign = Sec.AddressAlign;
SHeader.sh_entsize = 0;
+ // XXX: Really ugly right now. Should not be writing to `CBA` above
+ // (and setting sh_offset and sh_size) when going through this branch
+ // here.
+ if (Sec.Type == ELFYAML::ELF_SHT(SHT_SYMTAB))
+ handleSymtabSectionHeader<ELFT>(Sec.Symbols, State, SHeader);
SHeaders.push_back(SHeader);
}
- // String table header.
- Elf_Shdr StrTabSHeader;
- zero(StrTabSHeader);
- StrTabSHeader.sh_name = 0;
- StrTabSHeader.sh_type = SHT_STRTAB;
- StrTabSHeader.sh_flags = 0;
- StrTabSHeader.sh_addr = 0;
- StrTabSHeader.sh_offset = CBA.currentOffset();
- StrTabSHeader.sh_size = StrTab.size();
- StrTab.writeToStream(CBA.getOS());
- StrTabSHeader.sh_link = 0;
- StrTabSHeader.sh_info = 0;
- StrTabSHeader.sh_addralign = 1;
- StrTabSHeader.sh_entsize = 0;
+ // .strtab string table header.
+ Elf_Shdr DotStrTabSHeader;
+ zero(DotStrTabSHeader);
+ DotStrTabSHeader.sh_name = SHStrTab.addString(StringRef(".strtab"));
+ createStringTableSectionHeader(DotStrTabSHeader, State.getStringTable(), CBA);
+ SHeaders.push_back(DotStrTabSHeader);
+
+ // Section header string table header.
+ Elf_Shdr SHStrTabSHeader;
+ zero(SHStrTabSHeader);
+ createStringTableSectionHeader(SHStrTabSHeader, SHStrTab, CBA);
+ SHeaders.push_back(SHStrTabSHeader);
OS.write((const char *)&Header, sizeof(Header));
writeVectorData(OS, SHeaders);
- OS.write((const char *)&StrTabSHeader, sizeof(StrTabSHeader));
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::raw_ostream &Out, llvm::MemoryBuffer *Buf) {
errs() << "yaml2obj: Failed to parse YAML file!\n";
return 1;
}
- if (Doc.Header.Class == ELFYAML::ELF_ELFCLASS(ELF::ELFCLASS64)) {
- if (Doc.Header.Data == ELFYAML::ELF_ELFDATA(ELF::ELFDATA2LSB))
- writeELF<object::ELFType<support::little, 8, true> >(outs(), Doc);
+ using object::ELFType;
+ typedef ELFType<support::little, 8, true> LE64;
+ typedef ELFType<support::big, 8, true> BE64;
+ typedef ELFType<support::little, 4, false> LE32;
+ typedef ELFType<support::big, 4, false> BE32;
+ if (is64Bit(Doc)) {
+ if (isLittleEndian(Doc))
+ return writeELF<LE64>(outs(), Doc);
else
- writeELF<object::ELFType<support::big, 8, true> >(outs(), Doc);
+ return writeELF<BE64>(outs(), Doc);
} else {
- if (Doc.Header.Data == ELFYAML::ELF_ELFDATA(ELF::ELFDATA2LSB))
- writeELF<object::ELFType<support::little, 4, false> >(outs(), Doc);
+ if (isLittleEndian(Doc))
+ return writeELF<LE32>(outs(), Doc);
else
- writeELF<object::ELFType<support::big, 4, false> >(outs(), Doc);
+ return writeELF<BE32>(outs(), Doc);
}
-
- return 0;
}
projects / oota-llvm.git / blobdiff