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-rw-r--r--tools/yaml2obj/yaml2elf.cpp237
1 files changed, 162 insertions, 75 deletions
diff --git a/tools/yaml2obj/yaml2elf.cpp b/tools/yaml2obj/yaml2elf.cpp
index 21506d9..bb52cda 100644
--- a/tools/yaml2obj/yaml2elf.cpp
+++ b/tools/yaml2obj/yaml2elf.cpp
@@ -16,6 +16,7 @@
#include "llvm/ADT/ArrayRef.h"
#include "llvm/Object/ELFObjectFile.h"
#include "llvm/Object/ELFYAML.h"
+#include "llvm/Object/StringTableBuilder.h"
#include "llvm/Support/ELF.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/YAMLTraits.h"
@@ -23,47 +24,6 @@
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`).
@@ -94,23 +54,23 @@ public:
};
} // 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.
+// 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 SectionNameToIdxMap {
+class NameToIdxMap {
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);
+ bool addName(StringRef Name, unsigned i) {
+ StringMapEntry<int> &Entry = Map.GetOrCreateValue(Name, -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);
+ bool lookup(StringRef Name, unsigned &Idx) const {
+ StringMap<int>::const_iterator I = Map.find(Name);
if (I == Map.end())
return true;
Idx = I->getValue();
@@ -143,6 +103,8 @@ class ELFState {
typedef typename object::ELFFile<ELFT>::Elf_Ehdr Elf_Ehdr;
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;
@@ -150,10 +112,13 @@ class ELFState {
/// \brief The future ".shstrtab" section.
StringTableBuilder DotShStrtab;
- SectionNameToIdxMap SN2I;
+ 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);
bool initSectionHeaders(std::vector<Elf_Shdr> &SHeaders,
ContiguousBlobAccumulator &CBA);
@@ -164,6 +129,12 @@ class ELFState {
ContiguousBlobAccumulator &CBA);
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);
// - SHT_NULL entry (placed first, i.e. 0'th entry)
// - symbol table (.symtab) (placed third to last)
@@ -217,28 +188,48 @@ bool ELFState<ELFT>::initSectionHeaders(std::vector<Elf_Shdr> &SHeaders,
zero(SHeader);
SHeaders.push_back(SHeader);
+ for (const auto &Sec : Doc.Sections)
+ DotShStrtab.add(Sec->Name);
+ DotShStrtab.finalize();
+
for (const auto &Sec : Doc.Sections) {
zero(SHeader);
- SHeader.sh_name = DotShStrtab.addString(Sec.Name);
- SHeader.sh_type = Sec.Type;
- SHeader.sh_flags = Sec.Flags;
- SHeader.sh_addr = Sec.Address;
-
- Sec.Content.writeAsBinary(CBA.getOSAndAlignedOffset(SHeader.sh_offset));
- SHeader.sh_size = Sec.Content.binary_size();
+ 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()) {
+ if (!Sec->Link.empty()) {
unsigned Index;
- if (SN2I.lookupSection(Sec.Link, Index)) {
- errs() << "error: Unknown section referenced: '" << Sec.Link
- << "' at YAML section '" << Sec.Name << "'.\n";
- return false;;
+ 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;
}
- SHeader.sh_info = 0;
- SHeader.sh_addralign = Sec.AddressAlign;
- SHeader.sh_entsize = 0;
+
+ 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)) {
+ 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
+ llvm_unreachable("Unknown section type");
+
SHeaders.push_back(SHeader);
}
return true;
@@ -248,7 +239,7 @@ template <class ELFT>
void ELFState<ELFT>::initSymtabSectionHeader(Elf_Shdr &SHeader,
ContiguousBlobAccumulator &CBA) {
zero(SHeader);
- SHeader.sh_name = DotShStrtab.addString(StringRef(".symtab"));
+ 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.
@@ -262,6 +253,16 @@ void ELFState<ELFT>::initSymtabSectionHeader(Elf_Shdr &SHeader,
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);
@@ -276,10 +277,10 @@ void ELFState<ELFT>::initStrtabSectionHeader(Elf_Shdr &SHeader, StringRef Name,
StringTableBuilder &STB,
ContiguousBlobAccumulator &CBA) {
zero(SHeader);
- SHeader.sh_name = DotShStrtab.addString(Name);
+ SHeader.sh_name = DotShStrtab.getOffset(Name);
SHeader.sh_type = ELF::SHT_STRTAB;
- STB.writeToStream(CBA.getOSAndAlignedOffset(SHeader.sh_offset));
- SHeader.sh_size = STB.size();
+ CBA.getOSAndAlignedOffset(SHeader.sh_offset) << STB.data();
+ SHeader.sh_size = STB.data().size();
SHeader.sh_addralign = 1;
}
@@ -291,11 +292,11 @@ void ELFState<ELFT>::addSymbols(const std::vector<ELFYAML::Symbol> &Symbols,
Elf_Sym Symbol;
zero(Symbol);
if (!Sym.Name.empty())
- Symbol.st_name = DotStrtab.addString(Sym.Name);
+ Symbol.st_name = DotStrtab.getOffset(Sym.Name);
Symbol.setBindingAndType(SymbolBinding, Sym.Type);
if (!Sym.Section.empty()) {
unsigned Index;
- if (SN2I.lookupSection(Sym.Section, Index)) {
+ if (SN2I.lookup(Sym.Section, Index)) {
errs() << "error: Unknown section referenced: '" << Sym.Section
<< "' by YAML symbol " << Sym.Name << ".\n";
exit(1);
@@ -308,13 +309,71 @@ void ELFState<ELFT>::addSymbols(const std::vector<ELFYAML::Symbol> &Symbols,
}
}
+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);
+ 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;
+}
+
+template <class ELFT>
+bool
+ELFState<ELFT>::writeSectionContent(Elf_Shdr &SHeader,
+ const ELFYAML::RelocationSection &Section,
+ ContiguousBlobAccumulator &CBA) {
+ if (Section.Type != llvm::ELF::SHT_REL &&
+ Section.Type != llvm::ELF::SHT_RELA) {
+ errs() << "error: Invalid relocation section type.\n";
+ return false;
+ }
+
+ 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);
+
+ for (const auto &Rel : Section.Relocations) {
+ unsigned SymIdx;
+ if (SymN2I.lookup(Rel.Symbol, SymIdx)) {
+ errs() << "error: Unknown symbol referenced: '" << Rel.Symbol
+ << "' at YAML relocation.\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);
+ OS.write((const char *)&REntry, sizeof(REntry));
+ } else {
+ Elf_Rel REntry;
+ zero(REntry);
+ REntry.r_offset = Rel.Offset;
+ REntry.setSymbolAndType(SymIdx, Rel.Type);
+ OS.write((const char *)&REntry, sizeof(REntry));
+ }
+ }
+ return true;
+}
+
template <class ELFT> bool ELFState<ELFT>::buildSectionIndex() {
SN2I.addName(".symtab", getDotSymTabSecNo());
SN2I.addName(".strtab", getDotStrTabSecNo());
SN2I.addName(".shstrtab", getDotShStrTabSecNo());
for (unsigned i = 0, e = Doc.Sections.size(); i != e; ++i) {
- StringRef Name = Doc.Sections[i].Name;
+ StringRef Name = Doc.Sections[i]->Name;
if (Name.empty())
continue;
// "+ 1" to take into account the SHT_NULL entry.
@@ -328,11 +387,33 @@ template <class ELFT> bool ELFState<ELFT>::buildSectionIndex() {
}
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);
@@ -345,6 +426,12 @@ int ELFState<ELFT>::writeELF(raw_ostream &OS, const ELFYAML::Object &Doc) {
Header.e_ehsize + Header.e_shentsize * Header.e_shnum;
ContiguousBlobAccumulator CBA(SectionContentBeginOffset);
+ // Doc might not contain .symtab, .strtab and .shstrtab sections,
+ // but we will emit them, so make sure to add them to ShStrTabSHeader.
+ State.DotShStrtab.add(".symtab");
+ State.DotShStrtab.add(".strtab");
+ State.DotShStrtab.add(".shstrtab");
+
std::vector<Elf_Shdr> SHeaders;
if(!State.initSectionHeaders(SHeaders, CBA))
return 1;
@@ -395,13 +482,13 @@ int yaml2elf(llvm::raw_ostream &Out, llvm::MemoryBuffer *Buf) {
typedef ELFType<support::big, 4, false> BE32;
if (is64Bit(Doc)) {
if (isLittleEndian(Doc))
- return ELFState<LE64>::writeELF(outs(), Doc);
+ return ELFState<LE64>::writeELF(Out, Doc);
else
- return ELFState<BE64>::writeELF(outs(), Doc);
+ return ELFState<BE64>::writeELF(Out, Doc);
} else {
if (isLittleEndian(Doc))
- return ELFState<LE32>::writeELF(outs(), Doc);
+ return ELFState<LE32>::writeELF(Out, Doc);
else
- return ELFState<BE32>::writeELF(outs(), Doc);
+ return ELFState<BE32>::writeELF(Out, Doc);
}
}
generated by cgit v1.1 at 2024-12-22 16:43:26 +0000