Skip to content

Commit

Permalink
Revert r317046, "Object: Move some code from ELF.h into ELF.cpp."
Browse files Browse the repository at this point in the history
This change resulted in a measured 1.5-2% perf regression linking
chrome.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317371 91177308-0d34-0410-b5e6-96231b3b80d8
  • Loading branch information
pcc committed Nov 3, 2017
1 parent 4fedc84 commit 9cf32a0
Showing 2 changed files with 263 additions and 263 deletions.
263 changes: 263 additions & 0 deletions include/llvm/Object/ELF.h
Original file line number Diff line number Diff line change
@@ -204,6 +204,46 @@ getExtendedSymbolTableIndex(const typename ELFT::Sym *Sym,
return ShndxTable[Index];
}

template <class ELFT>
Expected<uint32_t>
ELFFile<ELFT>::getSectionIndex(const Elf_Sym *Sym, Elf_Sym_Range Syms,
ArrayRef<Elf_Word> ShndxTable) const {
uint32_t Index = Sym->st_shndx;
if (Index == ELF::SHN_XINDEX) {
auto ErrorOrIndex = getExtendedSymbolTableIndex<ELFT>(
Sym, Syms.begin(), ShndxTable);
if (!ErrorOrIndex)
return ErrorOrIndex.takeError();
return *ErrorOrIndex;
}
if (Index == ELF::SHN_UNDEF || Index >= ELF::SHN_LORESERVE)
return 0;
return Index;
}

template <class ELFT>
Expected<const typename ELFT::Shdr *>
ELFFile<ELFT>::getSection(const Elf_Sym *Sym, const Elf_Shdr *SymTab,
ArrayRef<Elf_Word> ShndxTable) const {
auto SymsOrErr = symbols(SymTab);
if (!SymsOrErr)
return SymsOrErr.takeError();
return getSection(Sym, *SymsOrErr, ShndxTable);
}

template <class ELFT>
Expected<const typename ELFT::Shdr *>
ELFFile<ELFT>::getSection(const Elf_Sym *Sym, Elf_Sym_Range Symbols,
ArrayRef<Elf_Word> ShndxTable) const {
auto IndexOrErr = getSectionIndex(Sym, Symbols, ShndxTable);
if (!IndexOrErr)
return IndexOrErr.takeError();
uint32_t Index = *IndexOrErr;
if (Index == 0)
return nullptr;
return getSection(Index);
}

template <class ELFT>
inline Expected<const typename ELFT::Sym *>
getSymbol(typename ELFT::SymRange Symbols, uint32_t Index) {
@@ -212,6 +252,15 @@ getSymbol(typename ELFT::SymRange Symbols, uint32_t Index) {
return &Symbols[Index];
}

template <class ELFT>
Expected<const typename ELFT::Sym *>
ELFFile<ELFT>::getSymbol(const Elf_Shdr *Sec, uint32_t Index) const {
auto SymtabOrErr = symbols(Sec);
if (!SymtabOrErr)
return SymtabOrErr.takeError();
return object::getSymbol<ELFT>(*SymtabOrErr, Index);
}

template <class ELFT>
template <typename T>
Expected<ArrayRef<T>>
@@ -232,6 +281,119 @@ ELFFile<ELFT>::getSectionContentsAsArray(const Elf_Shdr *Sec) const {
return makeArrayRef(Start, Size / sizeof(T));
}

template <class ELFT>
Expected<ArrayRef<uint8_t>>
ELFFile<ELFT>::getSectionContents(const Elf_Shdr *Sec) const {
return getSectionContentsAsArray<uint8_t>(Sec);
}

template <class ELFT>
StringRef ELFFile<ELFT>::getRelocationTypeName(uint32_t Type) const {
return getELFRelocationTypeName(getHeader()->e_machine, Type);
}

template <class ELFT>
void ELFFile<ELFT>::getRelocationTypeName(uint32_t Type,
SmallVectorImpl<char> &Result) const {
if (!isMipsELF64()) {
StringRef Name = getRelocationTypeName(Type);
Result.append(Name.begin(), Name.end());
} else {
// The Mips N64 ABI allows up to three operations to be specified per
// relocation record. Unfortunately there's no easy way to test for the
// presence of N64 ELFs as they have no special flag that identifies them
// as being N64. We can safely assume at the moment that all Mips
// ELFCLASS64 ELFs are N64. New Mips64 ABIs should provide enough
// information to disambiguate between old vs new ABIs.
uint8_t Type1 = (Type >> 0) & 0xFF;
uint8_t Type2 = (Type >> 8) & 0xFF;
uint8_t Type3 = (Type >> 16) & 0xFF;

// Concat all three relocation type names.
StringRef Name = getRelocationTypeName(Type1);
Result.append(Name.begin(), Name.end());

Name = getRelocationTypeName(Type2);
Result.append(1, '/');
Result.append(Name.begin(), Name.end());

Name = getRelocationTypeName(Type3);
Result.append(1, '/');
Result.append(Name.begin(), Name.end());
}
}

template <class ELFT>
Expected<const typename ELFT::Sym *>
ELFFile<ELFT>::getRelocationSymbol(const Elf_Rel *Rel,
const Elf_Shdr *SymTab) const {
uint32_t Index = Rel->getSymbol(isMips64EL());
if (Index == 0)
return nullptr;
return getEntry<Elf_Sym>(SymTab, Index);
}

template <class ELFT>
Expected<StringRef>
ELFFile<ELFT>::getSectionStringTable(Elf_Shdr_Range Sections) const {
uint32_t Index = getHeader()->e_shstrndx;
if (Index == ELF::SHN_XINDEX)
Index = Sections[0].sh_link;

if (!Index) // no section string table.
return "";
if (Index >= Sections.size())
return createError("invalid section index");
return getStringTable(&Sections[Index]);
}

template <class ELFT> ELFFile<ELFT>::ELFFile(StringRef Object) : Buf(Object) {}

template <class ELFT>
Expected<ELFFile<ELFT>> ELFFile<ELFT>::create(StringRef Object) {
if (sizeof(Elf_Ehdr) > Object.size())
return createError("Invalid buffer");
return ELFFile(Object);
}

template <class ELFT>
Expected<typename ELFT::ShdrRange> ELFFile<ELFT>::sections() const {
const uintX_t SectionTableOffset = getHeader()->e_shoff;
if (SectionTableOffset == 0)
return ArrayRef<Elf_Shdr>();

if (getHeader()->e_shentsize != sizeof(Elf_Shdr))
return createError(
"invalid section header entry size (e_shentsize) in ELF header");

const uint64_t FileSize = Buf.size();

if (SectionTableOffset + sizeof(Elf_Shdr) > FileSize)
return createError("section header table goes past the end of the file");

// Invalid address alignment of section headers
if (SectionTableOffset & (alignof(Elf_Shdr) - 1))
return createError("invalid alignment of section headers");

const Elf_Shdr *First =
reinterpret_cast<const Elf_Shdr *>(base() + SectionTableOffset);

uintX_t NumSections = getHeader()->e_shnum;
if (NumSections == 0)
NumSections = First->sh_size;

if (NumSections > UINT64_MAX / sizeof(Elf_Shdr))
return createError("section table goes past the end of file");

const uint64_t SectionTableSize = NumSections * sizeof(Elf_Shdr);

// Section table goes past end of file!
if (SectionTableOffset + SectionTableSize > FileSize)
return createError("section table goes past the end of file");

return makeArrayRef(First, NumSections);
}

template <class ELFT>
template <typename T>
Expected<const T *> ELFFile<ELFT>::getEntry(uint32_t Section,
@@ -254,6 +416,107 @@ Expected<const T *> ELFFile<ELFT>::getEntry(const Elf_Shdr *Section,
return reinterpret_cast<const T *>(base() + Pos);
}

template <class ELFT>
Expected<const typename ELFT::Shdr *>
ELFFile<ELFT>::getSection(uint32_t Index) const {
auto TableOrErr = sections();
if (!TableOrErr)
return TableOrErr.takeError();
return object::getSection<ELFT>(*TableOrErr, Index);
}

template <class ELFT>
Expected<StringRef>
ELFFile<ELFT>::getStringTable(const Elf_Shdr *Section) const {
if (Section->sh_type != ELF::SHT_STRTAB)
return createError("invalid sh_type for string table, expected SHT_STRTAB");
auto V = getSectionContentsAsArray<char>(Section);
if (!V)
return V.takeError();
ArrayRef<char> Data = *V;
if (Data.empty())
return createError("empty string table");
if (Data.back() != '\0')
return createError("string table non-null terminated");
return StringRef(Data.begin(), Data.size());
}

template <class ELFT>
Expected<ArrayRef<typename ELFT::Word>>
ELFFile<ELFT>::getSHNDXTable(const Elf_Shdr &Section) const {
auto SectionsOrErr = sections();
if (!SectionsOrErr)
return SectionsOrErr.takeError();
return getSHNDXTable(Section, *SectionsOrErr);
}

template <class ELFT>
Expected<ArrayRef<typename ELFT::Word>>
ELFFile<ELFT>::getSHNDXTable(const Elf_Shdr &Section,
Elf_Shdr_Range Sections) const {
assert(Section.sh_type == ELF::SHT_SYMTAB_SHNDX);
auto VOrErr = getSectionContentsAsArray<Elf_Word>(&Section);
if (!VOrErr)
return VOrErr.takeError();
ArrayRef<Elf_Word> V = *VOrErr;
auto SymTableOrErr = object::getSection<ELFT>(Sections, Section.sh_link);
if (!SymTableOrErr)
return SymTableOrErr.takeError();
const Elf_Shdr &SymTable = **SymTableOrErr;
if (SymTable.sh_type != ELF::SHT_SYMTAB &&
SymTable.sh_type != ELF::SHT_DYNSYM)
return createError("invalid sh_type");
if (V.size() != (SymTable.sh_size / sizeof(Elf_Sym)))
return createError("invalid section contents size");
return V;
}

template <class ELFT>
Expected<StringRef>
ELFFile<ELFT>::getStringTableForSymtab(const Elf_Shdr &Sec) const {
auto SectionsOrErr = sections();
if (!SectionsOrErr)
return SectionsOrErr.takeError();
return getStringTableForSymtab(Sec, *SectionsOrErr);
}

template <class ELFT>
Expected<StringRef>
ELFFile<ELFT>::getStringTableForSymtab(const Elf_Shdr &Sec,
Elf_Shdr_Range Sections) const {

if (Sec.sh_type != ELF::SHT_SYMTAB && Sec.sh_type != ELF::SHT_DYNSYM)
return createError(
"invalid sh_type for symbol table, expected SHT_SYMTAB or SHT_DYNSYM");
auto SectionOrErr = object::getSection<ELFT>(Sections, Sec.sh_link);
if (!SectionOrErr)
return SectionOrErr.takeError();
return getStringTable(*SectionOrErr);
}

template <class ELFT>
Expected<StringRef>
ELFFile<ELFT>::getSectionName(const Elf_Shdr *Section) const {
auto SectionsOrErr = sections();
if (!SectionsOrErr)
return SectionsOrErr.takeError();
auto Table = getSectionStringTable(*SectionsOrErr);
if (!Table)
return Table.takeError();
return getSectionName(Section, *Table);
}

template <class ELFT>
Expected<StringRef> ELFFile<ELFT>::getSectionName(const Elf_Shdr *Section,
StringRef DotShstrtab) const {
uint32_t Offset = Section->sh_name;
if (Offset == 0)
return StringRef();
if (Offset >= DotShstrtab.size())
return createError("invalid string offset");
return StringRef(DotShstrtab.data() + Offset);
}

/// This function returns the hash value for a symbol in the .dynsym section
/// Name of the API remains consistent as specified in the libelf
/// REF : http://www.sco.com/developers/gabi/latest/ch5.dynamic.html#hash
Loading

0 comments on commit 9cf32a0

Please sign in to comment.