[yaml2obj] Move core yaml2obj code into lib and include for use in unit tests
Reviewers: jhenderson, rupprecht, MaskRay, grimar, labath
Reviewed By: rupprecht
Subscribers: gribozavr, mgrang, seiya, mgorny, sbc100, hiraditya, aheejin, jakehehrlich, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65255
llvm-svn: 368119
diff --git a/llvm/lib/ObjectYAML/ELFEmitter.cpp b/llvm/lib/ObjectYAML/ELFEmitter.cpp
new file mode 100644
index 0000000..370d620
--- /dev/null
+++ b/llvm/lib/ObjectYAML/ELFEmitter.cpp
@@ -0,0 +1,1083 @@
+//===- 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/StringSet.h"
+#include "llvm/BinaryFormat/ELF.h"
+#include "llvm/MC/StringTableBuilder.h"
+#include "llvm/Object/ELFObjectFile.h"
+#include "llvm/ObjectYAML/ELFYAML.h"
+#include "llvm/ObjectYAML/yaml2obj.h"
+#include "llvm/Support/EndianStream.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`).
+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);
+ OS.write_zeros(AlignedOffset - CurrentOffset);
+ 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(); }
+};
+
+// 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(); }
+};
+
+/// "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 ELFT::Ehdr Elf_Ehdr;
+ typedef typename ELFT::Phdr Elf_Phdr;
+ typedef typename ELFT::Shdr Elf_Shdr;
+ typedef typename ELFT::Sym Elf_Sym;
+ typedef typename ELFT::Rel Elf_Rel;
+ typedef typename ELFT::Rela Elf_Rela;
+ typedef typename ELFT::Relr Elf_Relr;
+ typedef typename ELFT::Dyn Elf_Dyn;
+
+ 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;
+ ELFYAML::Object &Doc;
+
+ bool buildSectionIndex();
+ bool buildSymbolIndex(ArrayRef<ELFYAML::Symbol> Symbols);
+ void initELFHeader(Elf_Ehdr &Header);
+ void initProgramHeaders(std::vector<Elf_Phdr> &PHeaders);
+ bool initImplicitHeader(ELFState<ELFT> &State, ContiguousBlobAccumulator &CBA,
+ Elf_Shdr &Header, StringRef SecName,
+ ELFYAML::Section *YAMLSec);
+ bool initSectionHeaders(ELFState<ELFT> &State,
+ 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 setProgramHeaderLayout(std::vector<Elf_Phdr> &PHeaders,
+ std::vector<Elf_Shdr> &SHeaders);
+ bool 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::SymverSection &Section,
+ ContiguousBlobAccumulator &CBA);
+ bool writeSectionContent(Elf_Shdr &SHeader,
+ const ELFYAML::VerneedSection &Section,
+ ContiguousBlobAccumulator &CBA);
+ bool writeSectionContent(Elf_Shdr &SHeader,
+ const ELFYAML::VerdefSection &Section,
+ ContiguousBlobAccumulator &CBA);
+ bool writeSectionContent(Elf_Shdr &SHeader,
+ const ELFYAML::MipsABIFlags &Section,
+ ContiguousBlobAccumulator &CBA);
+ bool writeSectionContent(Elf_Shdr &SHeader,
+ const ELFYAML::DynamicSection &Section,
+ ContiguousBlobAccumulator &CBA);
+ ELFState(ELFYAML::Object &D);
+
+public:
+ static int writeELF(raw_ostream &OS, ELFYAML::Object &Doc);
+
+private:
+ void finalizeStrings();
+};
+} // 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) : Doc(D) {
+ StringSet<> DocSections;
+ for (std::unique_ptr<ELFYAML::Section> &D : Doc.Sections)
+ if (!D->Name.empty())
+ DocSections.insert(D->Name);
+
+ // Insert SHT_NULL section implicitly when it is not defined in YAML.
+ if (Doc.Sections.empty() || Doc.Sections.front()->Type != ELF::SHT_NULL)
+ Doc.Sections.insert(
+ Doc.Sections.begin(),
+ llvm::make_unique<ELFYAML::Section>(
+ ELFYAML::Section::SectionKind::RawContent, /*IsImplicit=*/true));
+
+ std::vector<StringRef> ImplicitSections = {".symtab", ".strtab", ".shstrtab"};
+ if (!Doc.DynamicSymbols.empty())
+ ImplicitSections.insert(ImplicitSections.end(), {".dynsym", ".dynstr"});
+
+ // 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 = llvm::make_unique<ELFYAML::Section>(
+ ELFYAML::Section::SectionKind::RawContent, true /*IsImplicit*/);
+ Sec->Name = SecName;
+ Doc.Sections.push_back(std::move(Sec));
+ }
+}
+
+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;
+ 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;
+ 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 =
+ Doc.Header.SHEntSize ? (uint16_t)*Doc.Header.SHEntSize : sizeof(Elf_Shdr);
+ // Immediately following the ELF header and program headers.
+ Header.e_shoff =
+ Doc.Header.SHOffset
+ ? (typename ELFT::uint)(*Doc.Header.SHOffset)
+ : sizeof(Header) + sizeof(Elf_Phdr) * Doc.ProgramHeaders.size();
+ Header.e_shnum =
+ Doc.Header.SHNum ? (uint16_t)*Doc.Header.SHNum : Doc.Sections.size();
+ Header.e_shstrndx = Doc.Header.SHStrNdx ? (uint16_t)*Doc.Header.SHStrNdx
+ : SN2I.get(".shstrtab");
+}
+
+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);
+ }
+}
+
+static bool convertSectionIndex(NameToIdxMap &SN2I, StringRef SecName,
+ StringRef IndexSrc, unsigned &IndexDest) {
+ if (!SN2I.lookup(IndexSrc, IndexDest) && !to_integer(IndexSrc, IndexDest)) {
+ WithColor::error() << "Unknown section referenced: '" << IndexSrc
+ << "' at YAML section '" << SecName << "'.\n";
+ return false;
+ }
+ return true;
+}
+
+template <class ELFT>
+bool ELFState<ELFT>::initImplicitHeader(ELFState<ELFT> &State,
+ 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")
+ State.initSymtabSectionHeader(Header, SymtabType::Static, CBA, YAMLSec);
+ else if (SecName == ".strtab")
+ State.initStrtabSectionHeader(Header, SecName, State.DotStrtab, CBA,
+ YAMLSec);
+ else if (SecName == ".shstrtab")
+ State.initStrtabSectionHeader(Header, SecName, State.DotShStrtab, CBA,
+ YAMLSec);
+
+ else if (SecName == ".dynsym")
+ State.initSymtabSectionHeader(Header, SymtabType::Dynamic, CBA, YAMLSec);
+ else if (SecName == ".dynstr")
+ State.initStrtabSectionHeader(Header, SecName, State.DotDynstr, CBA,
+ YAMLSec);
+ else
+ return false;
+
+ // Override the sh_offset/sh_size fields if requested.
+ if (YAMLSec) {
+ if (YAMLSec->ShOffset)
+ Header.sh_offset = *YAMLSec->ShOffset;
+ if (YAMLSec->ShSize)
+ Header.sh_size = *YAMLSec->ShSize;
+ }
+
+ return true;
+}
+
+static StringRef dropUniqueSuffix(StringRef S) {
+ size_t SuffixPos = S.rfind(" [");
+ if (SuffixPos == StringRef::npos)
+ return S;
+ return S.substr(0, SuffixPos);
+}
+
+template <class ELFT>
+bool ELFState<ELFT>::initSectionHeaders(ELFState<ELFT> &State,
+ 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.Sections.size());
+
+ for (size_t I = 0; I < Doc.Sections.size(); ++I) {
+ ELFYAML::Section *Sec = Doc.Sections[I].get();
+ if (I == 0 && Sec->IsImplicit)
+ continue;
+
+ // 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.
+ Elf_Shdr &SHeader = SHeaders[I];
+ if (initImplicitHeader(State, 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 = DotShStrtab.getOffset(dropUniqueSuffix(Sec->Name));
+ SHeader.sh_type = Sec->Type;
+ if (Sec->Flags)
+ SHeader.sh_flags = *Sec->Flags;
+ SHeader.sh_addr = Sec->Address;
+ SHeader.sh_addralign = Sec->AddressAlign;
+
+ if (!Sec->Link.empty()) {
+ unsigned Index;
+ if (!convertSectionIndex(SN2I, Sec->Name, Sec->Link, Index))
+ return false;
+ SHeader.sh_link = Index;
+ }
+
+ if (I == 0) {
+ 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;
+ }
+ if (Sec->EntSize)
+ SHeader.sh_entsize = *Sec->EntSize;
+ } else if (auto S = dyn_cast<ELFYAML::RawContentSection>(Sec)) {
+ if (!writeSectionContent(SHeader, *S, CBA))
+ return false;
+ } else if (auto S = dyn_cast<ELFYAML::RelocationSection>(Sec)) {
+ if (!writeSectionContent(SHeader, *S, CBA))
+ return false;
+ } else if (auto S = dyn_cast<ELFYAML::Group>(Sec)) {
+ if (!writeSectionContent(SHeader, *S, CBA))
+ return false;
+ } else if (auto S = dyn_cast<ELFYAML::MipsABIFlags>(Sec)) {
+ if (!writeSectionContent(SHeader, *S, CBA))
+ return false;
+ } else if (auto S = dyn_cast<ELFYAML::NoBitsSection>(Sec)) {
+ 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 if (auto S = dyn_cast<ELFYAML::DynamicSection>(Sec)) {
+ if (!writeSectionContent(SHeader, *S, CBA))
+ return false;
+ } else if (auto S = dyn_cast<ELFYAML::SymverSection>(Sec)) {
+ if (!writeSectionContent(SHeader, *S, CBA))
+ return false;
+ } else if (auto S = dyn_cast<ELFYAML::VerneedSection>(Sec)) {
+ if (!writeSectionContent(SHeader, *S, CBA))
+ return false;
+ } else if (auto S = dyn_cast<ELFYAML::VerdefSection>(Sec)) {
+ if (!writeSectionContent(SHeader, *S, CBA))
+ return false;
+ } else
+ llvm_unreachable("Unknown section type");
+
+ // Override the sh_offset/sh_size fields if requested.
+ if (Sec) {
+ if (Sec->ShOffset)
+ SHeader.sh_offset = *Sec->ShOffset;
+ if (Sec->ShSize)
+ SHeader.sh_size = *Sec->ShSize;
+ }
+ }
+
+ return true;
+}
+
+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();
+}
+
+static uint64_t writeRawSectionData(raw_ostream &OS,
+ const ELFYAML::RawContentSection &RawSec) {
+ size_t ContentSize = 0;
+ if (RawSec.Content) {
+ RawSec.Content->writeAsBinary(OS);
+ ContentSize = RawSec.Content->binary_size();
+ }
+
+ if (!RawSec.Size)
+ return ContentSize;
+
+ OS.write_zeros(*RawSec.Size - ContentSize);
+ return *RawSec.Size;
+}
+
+template <class ELFT>
+static std::vector<typename ELFT::Sym>
+toELFSymbols(NameToIdxMap &SN2I, ArrayRef<ELFYAML::Symbol> Symbols,
+ const StringTableBuilder &Strtab) {
+ using Elf_Sym = typename ELFT::Sym;
+
+ std::vector<Elf_Sym> Ret;
+ Ret.resize(Symbols.size() + 1);
+
+ size_t I = 0;
+ for (const auto &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.NameIndex)
+ Symbol.st_name = *Sym.NameIndex;
+ else if (!Sym.Name.empty())
+ Symbol.st_name = Strtab.getOffset(dropUniqueSuffix(Sym.Name));
+
+ Symbol.setBindingAndType(Sym.Binding, Sym.Type);
+ if (!Sym.Section.empty()) {
+ unsigned Index;
+ if (!SN2I.lookup(Sym.Section, Index)) {
+ WithColor::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;
+ }
+
+ return Ret;
+}
+
+template <class ELFT>
+void ELFState<ELFT>::initSymtabSectionHeader(Elf_Shdr &SHeader,
+ SymtabType STType,
+ ContiguousBlobAccumulator &CBA,
+ ELFYAML::Section *YAMLSec) {
+
+ bool IsStatic = STType == SymtabType::Static;
+ const auto &Symbols = IsStatic ? Doc.Symbols : Doc.DynamicSymbols;
+
+ ELFYAML::RawContentSection *RawSec =
+ dyn_cast_or_null<ELFYAML::RawContentSection>(YAMLSec);
+ if (RawSec && !Symbols.empty() && (RawSec->Content || RawSec->Size)) {
+ if (RawSec->Content)
+ WithColor::error() << "Cannot specify both `Content` and " +
+ (IsStatic ? Twine("`Symbols`")
+ : Twine("`DynamicSymbols`")) +
+ " for symbol table section '"
+ << RawSec->Name << "'.\n";
+ if (RawSec->Size)
+ WithColor::error() << "Cannot specify both `Size` and " +
+ (IsStatic ? Twine("`Symbols`")
+ : Twine("`DynamicSymbols`")) +
+ " for symbol table section '"
+ << RawSec->Name << "'.\n";
+ exit(1);
+ }
+
+ zero(SHeader);
+ SHeader.sh_name = DotShStrtab.getOffset(IsStatic ? ".symtab" : ".dynsym");
+
+ if (YAMLSec)
+ SHeader.sh_type = YAMLSec->Type;
+ else
+ SHeader.sh_type = IsStatic ? ELF::SHT_SYMTAB : ELF::SHT_DYNSYM;
+
+ if (RawSec && !RawSec->Link.empty()) {
+ // If the Link field is explicitly defined in the document,
+ // we should use it.
+ unsigned Index;
+ if (!convertSectionIndex(SN2I, RawSec->Name, RawSec->Link, Index))
+ return;
+ SHeader.sh_link = Index;
+ } else {
+ // When we describe the .dynsym section in the document explicitly, it is
+ // allowed to omit the "DynamicSymbols" tag. In this case .dynstr is not
+ // added implicitly and we should be able to leave the Link zeroed if
+ // .dynstr is not defined.
+ unsigned Link = 0;
+ if (IsStatic)
+ Link = SN2I.get(".strtab");
+ else
+ SN2I.lookup(".dynstr", Link);
+ SHeader.sh_link = Link;
+ }
+
+ 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_entsize = (YAMLSec && YAMLSec->EntSize)
+ ? (uint64_t)(*YAMLSec->EntSize)
+ : sizeof(Elf_Sym);
+ SHeader.sh_addralign = YAMLSec ? (uint64_t)YAMLSec->AddressAlign : 8;
+ SHeader.sh_addr = YAMLSec ? (uint64_t)YAMLSec->Address : 0;
+
+ auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
+ if (RawSec && (RawSec->Content || RawSec->Size)) {
+ assert(Symbols.empty());
+ SHeader.sh_size = writeRawSectionData(OS, *RawSec);
+ return;
+ }
+
+ std::vector<Elf_Sym> Syms =
+ toELFSymbols<ELFT>(SN2I, Symbols, IsStatic ? DotStrtab : DotDynstr);
+ writeArrayData(OS, makeArrayRef(Syms));
+ SHeader.sh_size = arrayDataSize(makeArrayRef(Syms));
+}
+
+template <class ELFT>
+void ELFState<ELFT>::initStrtabSectionHeader(Elf_Shdr &SHeader, StringRef Name,
+ StringTableBuilder &STB,
+ ContiguousBlobAccumulator &CBA,
+ ELFYAML::Section *YAMLSec) {
+ zero(SHeader);
+ SHeader.sh_name = DotShStrtab.getOffset(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);
+
+ auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
+ if (RawSec && (RawSec->Content || RawSec->Size)) {
+ SHeader.sh_size = writeRawSectionData(OS, *RawSec);
+ } else {
+ STB.write(OS);
+ SHeader.sh_size = STB.getSize();
+ }
+
+ if (YAMLSec && YAMLSec->EntSize)
+ SHeader.sh_entsize = *YAMLSec->EntSize;
+
+ 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;
+
+ // If the section is explicitly described in the YAML
+ // then we want to use its section address.
+ if (YAMLSec)
+ SHeader.sh_addr = YAMLSec->Address;
+}
+
+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<Elf_Shdr *> Sections;
+ for (const ELFYAML::SectionName &SecName : YamlPhdr.Sections) {
+ unsigned Index;
+ if (!SN2I.lookup(SecName.Section, Index)) {
+ WithColor::error() << "Unknown section referenced: '" << SecName.Section
+ << "' by program header.\n";
+ exit(1);
+ }
+ Sections.push_back(&SHeaders[Index]);
+ }
+
+ if (YamlPhdr.Offset) {
+ PHeader.p_offset = *YamlPhdr.Offset;
+ } else {
+ if (YamlPhdr.Sections.size())
+ PHeader.p_offset = UINT32_MAX;
+ else
+ PHeader.p_offset = 0;
+
+ // Find the minimum offset for the program header.
+ for (Elf_Shdr *SHeader : Sections)
+ 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,
+ // if not set explicitly.
+ if (YamlPhdr.FileSize) {
+ PHeader.p_filesz = *YamlPhdr.FileSize;
+ } else {
+ PHeader.p_filesz = 0;
+ for (Elf_Shdr *SHeader : Sections) {
+ 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;
+ }
+ }
+
+ // If not set explicitly, 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.
+ if (YamlPhdr.MemSize) {
+ PHeader.p_memsz = *YamlPhdr.MemSize;
+ } else {
+ PHeader.p_memsz = PHeader.p_filesz;
+ for (Elf_Shdr *SHeader : Sections)
+ 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 (Elf_Shdr *SHeader : Sections)
+ if (SHeader->sh_offset == PHeader.p_offset)
+ PHeader.p_align = std::max(PHeader.p_align, SHeader->sh_addralign);
+ }
+ }
+}
+
+template <class ELFT>
+bool ELFState<ELFT>::writeSectionContent(
+ Elf_Shdr &SHeader, const ELFYAML::RawContentSection &Section,
+ ContiguousBlobAccumulator &CBA) {
+ raw_ostream &OS =
+ CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
+ SHeader.sh_size = writeRawSectionData(OS, Section);
+
+ if (Section.EntSize)
+ SHeader.sh_entsize = *Section.EntSize;
+ else if (Section.Type == llvm::ELF::SHT_RELR)
+ SHeader.sh_entsize = sizeof(Elf_Relr);
+ else
+ SHeader.sh_entsize = 0;
+
+ if (Section.Info)
+ SHeader.sh_info = *Section.Info;
+
+ return true;
+}
+
+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();
+
+ // For relocation section set link to .symtab by default.
+ if (Section.Link.empty())
+ SHeader.sh_link = SN2I.get(".symtab");
+
+ unsigned Index = 0;
+ if (!Section.RelocatableSec.empty() &&
+ !convertSectionIndex(SN2I, Section.Name, Section.RelocatableSec, Index))
+ return false;
+ SHeader.sh_info = Index;
+
+ auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
+
+ for (const auto &Rel : Section.Relocations) {
+ unsigned SymIdx = 0;
+ // If a relocation references a symbol, try to look one up in the symbol
+ // table. If it is not there, treat the value as a symbol index.
+ if (Rel.Symbol && !SymN2I.lookup(*Rel.Symbol, SymIdx) &&
+ !to_integer(*Rel.Symbol, SymIdx)) {
+ WithColor::error() << "Unknown symbol referenced: '" << *Rel.Symbol
+ << "' at YAML section '" << Section.Name << "'.\n";
+ return false;
+ }
+
+ 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) {
+ assert(Section.Type == llvm::ELF::SHT_GROUP &&
+ "Section type is not SHT_GROUP");
+
+ SHeader.sh_entsize = 4;
+ SHeader.sh_size = SHeader.sh_entsize * Section.Members.size();
+
+ unsigned SymIdx;
+ if (!SymN2I.lookup(Section.Signature, SymIdx) &&
+ !to_integer(Section.Signature, SymIdx)) {
+ WithColor::error() << "Unknown symbol referenced: '" << Section.Signature
+ << "' at YAML section '" << Section.Name << "'.\n";
+ return false;
+ }
+ SHeader.sh_info = SymIdx;
+
+ raw_ostream &OS =
+ CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
+
+ for (const ELFYAML::SectionOrType &Member : Section.Members) {
+ unsigned int SectionIndex = 0;
+ if (Member.sectionNameOrType == "GRP_COMDAT")
+ SectionIndex = llvm::ELF::GRP_COMDAT;
+ else if (!convertSectionIndex(SN2I, Section.Name, Member.sectionNameOrType,
+ SectionIndex))
+ return false;
+ support::endian::write<uint32_t>(OS, SectionIndex, ELFT::TargetEndianness);
+ }
+ return true;
+}
+
+template <class ELFT>
+bool ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
+ const ELFYAML::SymverSection &Section,
+ ContiguousBlobAccumulator &CBA) {
+ raw_ostream &OS =
+ CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
+ for (uint16_t Version : Section.Entries)
+ support::endian::write<uint16_t>(OS, Version, ELFT::TargetEndianness);
+
+ SHeader.sh_entsize = Section.EntSize ? (uint64_t)*Section.EntSize : 2;
+ SHeader.sh_size = Section.Entries.size() * SHeader.sh_entsize;
+ return true;
+}
+
+template <class ELFT>
+bool ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
+ const ELFYAML::VerdefSection &Section,
+ ContiguousBlobAccumulator &CBA) {
+ typedef typename ELFT::Verdef Elf_Verdef;
+ typedef typename ELFT::Verdaux Elf_Verdaux;
+ raw_ostream &OS =
+ CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
+
+ 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;
+ VerDef.vd_flags = E.Flags;
+ VerDef.vd_ndx = E.VersionNdx;
+ VerDef.vd_hash = E.Hash;
+ 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);
+ OS.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);
+ OS.write((const char *)&VernAux, sizeof(Elf_Verdaux));
+ }
+ }
+
+ SHeader.sh_size = Section.Entries.size() * sizeof(Elf_Verdef) +
+ AuxCnt * sizeof(Elf_Verdaux);
+ SHeader.sh_info = Section.Info;
+
+ return true;
+}
+
+template <class ELFT>
+bool ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
+ const ELFYAML::VerneedSection &Section,
+ ContiguousBlobAccumulator &CBA) {
+ typedef typename ELFT::Verneed Elf_Verneed;
+ typedef typename ELFT::Vernaux Elf_Vernaux;
+
+ auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
+
+ 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);
+ OS.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);
+ OS.write((const char *)&VernAux, sizeof(Elf_Vernaux));
+ }
+ }
+
+ SHeader.sh_size = Section.VerneedV.size() * sizeof(Elf_Verneed) +
+ AuxCnt * sizeof(Elf_Vernaux);
+ SHeader.sh_info = Section.Info;
+
+ 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>::writeSectionContent(Elf_Shdr &SHeader,
+ const ELFYAML::DynamicSection &Section,
+ ContiguousBlobAccumulator &CBA) {
+ typedef typename ELFT::uint uintX_t;
+
+ assert(Section.Type == llvm::ELF::SHT_DYNAMIC &&
+ "Section type is not SHT_DYNAMIC");
+
+ if (!Section.Entries.empty() && Section.Content) {
+ WithColor::error()
+ << "Cannot specify both raw content and explicit entries "
+ "for dynamic section '"
+ << Section.Name << "'.\n";
+ return false;
+ }
+
+ if (Section.Content)
+ SHeader.sh_size = Section.Content->binary_size();
+ else
+ SHeader.sh_size = 2 * sizeof(uintX_t) * Section.Entries.size();
+ if (Section.EntSize)
+ SHeader.sh_entsize = *Section.EntSize;
+ else
+ SHeader.sh_entsize = sizeof(Elf_Dyn);
+
+ raw_ostream &OS =
+ CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
+ for (const ELFYAML::DynamicEntry &DE : Section.Entries) {
+ support::endian::write<uintX_t>(OS, DE.Tag, ELFT::TargetEndianness);
+ support::endian::write<uintX_t>(OS, DE.Val, ELFT::TargetEndianness);
+ }
+ if (Section.Content)
+ Section.Content->writeAsBinary(OS);
+
+ 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;
+ if (Name.empty())
+ continue;
+
+ DotShStrtab.add(dropUniqueSuffix(Name));
+ if (!SN2I.addName(Name, I)) {
+ WithColor::error() << "Repeated section name: '" << Name
+ << "' at YAML section number " << I << ".\n";
+ return false;
+ }
+ }
+
+ DotShStrtab.finalize();
+ return true;
+}
+
+template <class ELFT>
+bool ELFState<ELFT>::buildSymbolIndex(ArrayRef<ELFYAML::Symbol> Symbols) {
+ bool GlobalSymbolSeen = false;
+ std::size_t I = 0;
+ for (const auto &Sym : Symbols) {
+ ++I;
+
+ StringRef Name = Sym.Name;
+ if (Sym.Binding.value == ELF::STB_LOCAL && GlobalSymbolSeen) {
+ WithColor::error() << "Local symbol '" + Name +
+ "' after global in Symbols list.\n";
+ return false;
+ }
+ if (Sym.Binding.value != ELF::STB_LOCAL)
+ GlobalSymbolSeen = true;
+
+ if (!Name.empty() && !SymN2I.addName(Name, I)) {
+ WithColor::error() << "Repeated symbol name: '" << Name << "'.\n";
+ return false;
+ }
+ }
+ return true;
+}
+
+template <class ELFT> void ELFState<ELFT>::finalizeStrings() {
+ // Add the regular symbol names to .strtab section.
+ for (const ELFYAML::Symbol &Sym : Doc.Symbols)
+ DotStrtab.add(dropUniqueSuffix(Sym.Name));
+ DotStrtab.finalize();
+
+ // Add the dynamic symbol names to .dynstr section.
+ for (const ELFYAML::Symbol &Sym : Doc.DynamicSymbols)
+ DotDynstr.add(dropUniqueSuffix(Sym.Name));
+
+ // SHT_GNU_verdef and SHT_GNU_verneed sections might also
+ // add strings to .dynstr section.
+ for (const std::unique_ptr<ELFYAML::Section> &Sec : Doc.Sections) {
+ if (auto VerNeed = dyn_cast<ELFYAML::VerneedSection>(Sec.get())) {
+ 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.get())) {
+ for (const ELFYAML::VerdefEntry &E : VerDef->Entries)
+ for (StringRef Name : E.VerNames)
+ DotDynstr.add(Name);
+ }
+ }
+
+ DotDynstr.finalize();
+}
+
+template <class ELFT>
+int ELFState<ELFT>::writeELF(raw_ostream &OS, ELFYAML::Object &Doc) {
+ ELFState<ELFT> State(Doc);
+
+ // 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();
+
+ if (!State.buildSectionIndex())
+ return 1;
+
+ if (!State.buildSymbolIndex(Doc.Symbols))
+ 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(State, SHeaders, CBA))
+ return 1;
+
+ // 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;
+}
+
+namespace llvm {
+namespace yaml {
+
+int yaml2elf(llvm::ELFYAML::Object &Doc, raw_ostream &Out) {
+ 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);
+ return ELFState<object::ELF64BE>::writeELF(Out, Doc);
+ }
+ if (IsLE)
+ return ELFState<object::ELF32LE>::writeELF(Out, Doc);
+ return ELFState<object::ELF32BE>::writeELF(Out, Doc);
+}
+
+} // namespace yaml
+} // namespace llvm