using namespace llvm;
+// There is similar code in yaml2coff, but with some slight COFF-specific
+// variations like different initial state. Might be able to deduplicate
+// some day, but also want to make sure that the Mach-O use case is served.
+//
+// This class has a deliberately small interface, since a lot of
+// implementation variation is possible.
+//
+// TODO: Use an ordered container with a suffix-based comparison in order
+// 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;
+ /// \brief The contents of the string table as we build it.
+ std::string Buf;
+public:
+ StringTableBuilder() {
+ Buf.push_back('\0');
+ }
+ /// \returns Index of string in string table.
+ unsigned addString(StringRef S) {
+ StringMapEntry<unsigned> &Entry = StringIndices.GetOrCreateValue(S);
+ unsigned &I = Entry.getValue();
+ if (I != 0)
+ return I;
+ I = Buf.size();
+ Buf.append(S.begin(), S.end());
+ Buf.push_back('\0');
+ return I;
+ }
+ size_t size() const {
+ return Buf.size();
+ }
+ void writeToStream(raw_ostream &OS) {
+ 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;
+
+public:
+ ContiguousBlobAccumulator(uint64_t InitialOffset_)
+ : InitialOffset(InitialOffset_), Buf(), OS(Buf) {}
+ raw_ostream &getOS() { return OS; }
+ uint64_t currentOffset() const { return InitialOffset + OS.tell(); }
+ 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) {
+ return Vec.size() * sizeof(T);
+}
+
+template <class T>
+static void writeVectorData(raw_ostream &OS, const std::vector<T> &Vec) {
+ OS.write((const char *)Vec.data(), vectorDataSize(Vec));
+}
+
+template <class T>
+static void zero(T &Obj) {
+ 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;
+ SHeader.sh_offset = CBA.currentOffset();
+ SHeader.sh_size = STB.size();
+ STB.writeToStream(CBA.getOS());
+ SHeader.sh_addralign = 1;
+}
+
+// FIXME: This function is hideous. Between the sheer number of parameters
+// and the hideous ELF typenames, it's just a travesty. Factor the ELF
+// output into a class (templated on ELFT) and share some typedefs.
template <class ELFT>
-static void writeELF(raw_ostream &OS, const ELFYAML::Object &Doc) {
- const ELFYAML::FileHeader &Hdr = Doc.Header;
+static void handleSymtabSectionHeader(
+ const ELFYAML::Section &Sec,
+ typename object::ELFObjectFile<ELFT>::Elf_Shdr &SHeader,
+ StringTableBuilder &StrTab, ContiguousBlobAccumulator &CBA,
+ unsigned DotStrtabSecNo) {
+
+ 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 = DotStrtabSecNo;
+ // TODO: Once we handle symbol binding, this should be one greater than
+ // symbol table index of the last local symbol.
+ SHeader.sh_info = 0;
+ 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);
+ }
+ for (unsigned i = 0, e = Sec.Symbols.size(); i != e; ++i) {
+ const ELFYAML::Symbol &Sym = Sec.Symbols[i];
+ Elf_Sym Symbol;
+ zero(Symbol);
+ if (!Sym.Name.empty())
+ Symbol.st_name = StrTab.addString(Sym.Name);
+ Symbol.setBindingAndType(Sym.Binding, Sym.Type);
+ Syms.push_back(Symbol);
+ }
+
+ SHeader.sh_offset = CBA.currentOffset();
+ SHeader.sh_size = vectorDataSize(Syms);
+ writeVectorData(CBA.getOS(), Syms);
+}
+
+template <class ELFT>
+static int writeELF(raw_ostream &OS, const ELFYAML::Object &Doc) {
using namespace llvm::ELF;
- using namespace llvm::object;
- typename ELFObjectFile<ELFT>::Elf_Ehdr Header;
- memset(&Header, 0, sizeof(Header));
+ typedef typename object::ELFObjectFile<ELFT>::Elf_Ehdr Elf_Ehdr;
+ typedef typename object::ELFObjectFile<ELFT>::Elf_Shdr Elf_Shdr;
+
+ const ELFYAML::FileHeader &Hdr = Doc.Header;
+
+ 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_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;
-
- // 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_version = EV_CURRENT;
Header.e_entry = Hdr.Entry;
- Header.e_ehsize = sizeof(Header);
+ Header.e_ehsize = sizeof(Elf_Ehdr);
+
+ // TODO: Flesh out section header support.
+ // TODO: Program headers.
- // TODO: Section headers and program headers.
+ Header.e_shentsize = sizeof(Elf_Shdr);
+ // Immediately following the ELF header.
+ Header.e_shoff = sizeof(Header);
+ 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 = Header.e_shnum - 1;
+ const unsigned DotStrtabSecNo = Header.e_shnum - 2;
+
+ 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;
+ }
+ }
+
+ StringTableBuilder SHStrTab;
+ // 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);
+ 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);
+ }
+ StringTableBuilder DotStrTab;
+ for (unsigned i = 0, e = Sections.size(); i != e; ++i) {
+ const ELFYAML::Section &Sec = Sections[i];
+ Elf_Shdr SHeader;
+ zero(SHeader);
+ 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();
+ SHeader.sh_size = Sec.Content.binary_size();
+ Sec.Content.writeAsBinary(CBA.getOS());
+
+ 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 = Sec.AddressAlign;
+ SHeader.sh_entsize = 0;
+ // XXX: Really ugly right now. Need to put common state into a class.
+ if (Sec.Type == ELFYAML::ELF_SHT(SHT_SYMTAB))
+ handleSymtabSectionHeader<ELFT>(Sec, SHeader, DotStrTab, CBA,
+ DotStrtabSecNo);
+ SHeaders.push_back(SHeader);
+ }
+
+ // .strtab string table header.
+ Elf_Shdr DotStrTabSHeader;
+ zero(DotStrTabSHeader);
+ DotStrTabSHeader.sh_name = SHStrTab.addString(StringRef(".strtab"));
+ createStringTableSectionHeader(DotStrTabSHeader, DotStrTab, CBA);
+
+ // Section header string table header.
+ Elf_Shdr SHStrTabSHeader;
+ zero(SHStrTabSHeader);
+ createStringTableSectionHeader(SHStrTabSHeader, SHStrTab, CBA);
OS.write((const char *)&Header, sizeof(Header));
+ writeVectorData(OS, SHeaders);
+ OS.write((const char *)&DotStrTabSHeader, sizeof(DotStrTabSHeader));
+ OS.write((const char *)&SHStrTabSHeader, sizeof(SHStrTabSHeader));
+ CBA.writeBlobToStream(OS);
+ return 0;
}
int yaml2elf(llvm::raw_ostream &Out, llvm::MemoryBuffer *Buf) {
}
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);
+ return writeELF<object::ELFType<support::little, 8, true> >(outs(), Doc);
else
- writeELF<object::ELFType<support::big, 8, true> >(outs(), Doc);
+ return writeELF<object::ELFType<support::big, 8, true> >(outs(), Doc);
} else {
if (Doc.Header.Data == ELFYAML::ELF_ELFDATA(ELF::ELFDATA2LSB))
- writeELF<object::ELFType<support::little, 4, false> >(outs(), Doc);
+ return writeELF<object::ELFType<support::little, 4, false> >(outs(), Doc);
else
- writeELF<object::ELFType<support::big, 4, false> >(outs(), Doc);
+ return writeELF<object::ELFType<support::big, 4, false> >(outs(), Doc);
}
-
- return 0;
}
projects / oota-llvm.git / blobdiff