X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FObject%2FELF.h;h=eed9bdd69e92de63838e10d1403193e7ea7d1db2;hb=0377a22491ed19ba2d9a6fc0ed34c901a3f56faa;hp=7953dba164f1d4118157521045ecbef93cb411dd;hpb=28bec63a7e95493f681a305c1a6e3b367835d814;p=oota-llvm.git

diff --git a/include/llvm/Object/ELF.h b/include/llvm/Object/ELF.h
index 7953dba164f..eed9bdd69e9 100644
--- a/include/llvm/Object/ELF.h
+++ b/include/llvm/Object/ELF.h
@@ -139,12 +139,9 @@ public:
   typedef Elf_Verneed_Impl<ELFT> Elf_Verneed;
   typedef Elf_Vernaux_Impl<ELFT> Elf_Vernaux;
   typedef Elf_Versym_Impl<ELFT> Elf_Versym;
-  typedef ELFEntityIterator<const Elf_Dyn> Elf_Dyn_Iter;
-  typedef iterator_range<Elf_Dyn_Iter> Elf_Dyn_Range;
-  typedef ELFEntityIterator<const Elf_Rela> Elf_Rela_Iter;
-  typedef ELFEntityIterator<const Elf_Rel> Elf_Rel_Iter;
-  typedef ELFEntityIterator<const Elf_Shdr> Elf_Shdr_Iter;
-  typedef iterator_range<Elf_Shdr_Iter> Elf_Shdr_Range;
+  typedef Elf_Hash_Impl<ELFT> Elf_Hash;
+  typedef iterator_range<const Elf_Dyn *> Elf_Dyn_Range;
+  typedef iterator_range<const Elf_Shdr *> Elf_Shdr_Range;
 
   /// \brief Archive files are 2 byte aligned, so we need this for
   ///     PointerIntPair to work.
@@ -171,17 +168,19 @@ private:
   }
 
   const Elf_Ehdr *Header;
-  const Elf_Shdr *SectionHeaderTable;
-  StringRef DotShstrtab;            // Section header string table.
-  StringRef DotStrtab;              // Symbol header string table.
-  const Elf_Shdr *dot_symtab_sec;   // Symbol table section.
-
-  const Elf_Shdr *SymbolTableSectionHeaderIndex;
+  const Elf_Shdr *SectionHeaderTable = nullptr;
+  StringRef DotShstrtab;                    // Section header string table.
+  StringRef DotStrtab;                      // Symbol header string table.
+  const Elf_Shdr *dot_symtab_sec = nullptr; // Symbol table section.
+  const Elf_Shdr *DotDynSymSec = nullptr;   // Dynamic symbol table section.
+  const Elf_Hash *HashTable = nullptr;
+
+  const Elf_Shdr *SymbolTableSectionHeaderIndex = nullptr;
   DenseMap<const Elf_Sym *, ELF::Elf64_Word> ExtendedSymbolTable;
 
-  const Elf_Shdr *dot_gnu_version_sec;   // .gnu.version
-  const Elf_Shdr *dot_gnu_version_r_sec; // .gnu.version_r
-  const Elf_Shdr *dot_gnu_version_d_sec; // .gnu.version_d
+  const Elf_Shdr *dot_gnu_version_sec = nullptr;   // .gnu.version
+  const Elf_Shdr *dot_gnu_version_r_sec = nullptr; // .gnu.version_r
+  const Elf_Shdr *dot_gnu_version_d_sec = nullptr; // .gnu.version_d
 
   /// \brief Represents a region described by entries in the .dynamic table.
   struct DynRegionInfo {
@@ -197,12 +196,11 @@ private:
   DynRegionInfo DynamicRegion;
   DynRegionInfo DynHashRegion;
   DynRegionInfo DynStrRegion;
-  DynRegionInfo DynSymRegion;
   DynRegionInfo DynRelaRegion;
 
   // Pointer to SONAME entry in dynamic string table
   // This is set the first time getLoadName is called.
-  mutable const char *dt_soname;
+  mutable const char *dt_soname = nullptr;
 
   // Records for each version index the corresponding Verdef or Vernaux entry.
   // This is filled the first time LoadVersionMap() is called.
@@ -230,11 +228,18 @@ private:
   void LoadVersionNeeds(const Elf_Shdr *ec) const;
   void LoadVersionMap() const;
 
+  void scanDynamicTable();
+
 public:
   template<typename T>
   const T        *getEntry(uint32_t Section, uint32_t Entry) const;
   template <typename T>
   const T *getEntry(const Elf_Shdr *Section, uint32_t Entry) const;
+
+  const Elf_Shdr *getDotSymtabSec() const { return dot_symtab_sec; }
+  const Elf_Shdr *getDotDynSymSec() const { return DotDynSymSec; }
+  const Elf_Hash *getHashTable() const { return HashTable; }
+
   ErrorOr<StringRef> getStringTable(const Elf_Shdr *Section) const;
   const char *getDynamicString(uintX_t Offset) const;
   ErrorOr<StringRef> getSymbolVersion(const Elf_Shdr *section,
@@ -264,8 +269,8 @@ public:
       Header->getDataEncoding() == ELF::ELFDATA2LSB;
   }
 
-  Elf_Shdr_Iter section_begin() const;
-  Elf_Shdr_Iter section_end() const;
+  const Elf_Shdr *section_begin() const;
+  const Elf_Shdr *section_end() const;
   Elf_Shdr_Range sections() const {
     return make_range(section_begin(), section_end());
   }
@@ -276,90 +281,108 @@ public:
     return make_range(symbol_begin(), symbol_end());
   }
 
-  Elf_Dyn_Iter dynamic_table_begin() const;
-  /// \param NULLEnd use one past the first DT_NULL entry as the end instead of
-  /// the section size.
-  Elf_Dyn_Iter dynamic_table_end(bool NULLEnd = false) const;
-  Elf_Dyn_Range dynamic_table(bool NULLEnd = false) const {
-    return make_range(dynamic_table_begin(), dynamic_table_end(NULLEnd));
+  const Elf_Dyn *dynamic_table_begin() const;
+  const Elf_Dyn *dynamic_table_end() const;
+  Elf_Dyn_Range dynamic_table() const {
+    return make_range(dynamic_table_begin(), dynamic_table_end());
   }
 
   const Elf_Sym *dynamic_symbol_begin() const {
-    if (!DynSymRegion.Addr)
+    if (!DotDynSymSec)
       return nullptr;
-    if (DynSymRegion.EntSize != sizeof(Elf_Sym))
+    if (DotDynSymSec->sh_entsize != sizeof(Elf_Sym))
       report_fatal_error("Invalid symbol size");
-    return reinterpret_cast<const Elf_Sym *>(DynSymRegion.Addr);
+    return reinterpret_cast<const Elf_Sym *>(base() + DotDynSymSec->sh_offset);
   }
 
   const Elf_Sym *dynamic_symbol_end() const {
-    if (!DynSymRegion.Addr)
+    if (!DotDynSymSec)
       return nullptr;
-    return reinterpret_cast<const Elf_Sym *>(
-        ((const char *)DynSymRegion.Addr + DynSymRegion.Size));
+    return reinterpret_cast<const Elf_Sym *>(base() + DotDynSymSec->sh_offset +
+                                             DotDynSymSec->sh_size);
   }
 
   Elf_Sym_Range dynamic_symbols() const {
     return make_range(dynamic_symbol_begin(), dynamic_symbol_end());
   }
 
-  Elf_Rela_Iter dyn_rela_begin() const {
-    if (DynRelaRegion.Addr)
-      return Elf_Rela_Iter(DynRelaRegion.EntSize,
-        (const char *)DynRelaRegion.Addr);
-    return Elf_Rela_Iter(0, nullptr);
+  const Elf_Rela *dyn_rela_begin() const {
+    if (DynRelaRegion.Size && DynRelaRegion.EntSize != sizeof(Elf_Rela))
+      report_fatal_error("Invalid relocation entry size");
+    return reinterpret_cast<const Elf_Rela *>(DynRelaRegion.Addr);
   }
 
-  Elf_Rela_Iter dyn_rela_end() const {
-    if (DynRelaRegion.Addr)
-      return Elf_Rela_Iter(
-        DynRelaRegion.EntSize,
-        (const char *)DynRelaRegion.Addr + DynRelaRegion.Size);
-    return Elf_Rela_Iter(0, nullptr);
+  const Elf_Rela *dyn_rela_end() const {
+    uint64_t Size = DynRelaRegion.Size;
+    if (Size % sizeof(Elf_Rela))
+      report_fatal_error("Invalid relocation table size");
+    return dyn_rela_begin() + Size / sizeof(Elf_Rela);
+  }
+
+  typedef iterator_range<const Elf_Rela *> Elf_Rela_Range;
+
+  Elf_Rela_Range dyn_relas() const {
+    return make_range(dyn_rela_begin(), dyn_rela_end());
   }
 
-  Elf_Rela_Iter rela_begin(const Elf_Shdr *sec) const {
-    return Elf_Rela_Iter(sec->sh_entsize,
-                         (const char *)(base() + sec->sh_offset));
+  const Elf_Rela *rela_begin(const Elf_Shdr *sec) const {
+    if (sec->sh_entsize != sizeof(Elf_Rela))
+      report_fatal_error("Invalid relocation entry size");
+    return reinterpret_cast<const Elf_Rela *>(base() + sec->sh_offset);
   }
 
-  Elf_Rela_Iter rela_end(const Elf_Shdr *sec) const {
-    return Elf_Rela_Iter(
-        sec->sh_entsize,
-        (const char *)(base() + sec->sh_offset + sec->sh_size));
+  const Elf_Rela *rela_end(const Elf_Shdr *sec) const {
+    uint64_t Size = sec->sh_size;
+    if (Size % sizeof(Elf_Rela))
+      report_fatal_error("Invalid relocation table size");
+    return rela_begin(sec) + Size / sizeof(Elf_Rela);
   }
 
-  Elf_Rel_Iter rel_begin(const Elf_Shdr *sec) const {
-    return Elf_Rel_Iter(sec->sh_entsize,
-                        (const char *)(base() + sec->sh_offset));
+  Elf_Rela_Range relas(const Elf_Shdr *Sec) const {
+    return make_range(rela_begin(Sec), rela_end(Sec));
   }
 
-  Elf_Rel_Iter rel_end(const Elf_Shdr *sec) const {
-    return Elf_Rel_Iter(sec->sh_entsize,
-                        (const char *)(base() + sec->sh_offset + sec->sh_size));
+  const Elf_Rel *rel_begin(const Elf_Shdr *sec) const {
+    if (sec->sh_entsize != sizeof(Elf_Rel))
+      report_fatal_error("Invalid relocation entry size");
+    return reinterpret_cast<const Elf_Rel *>(base() + sec->sh_offset);
+  }
+
+  const Elf_Rel *rel_end(const Elf_Shdr *sec) const {
+    uint64_t Size = sec->sh_size;
+    if (Size % sizeof(Elf_Rel))
+      report_fatal_error("Invalid relocation table size");
+    return rel_begin(sec) + Size / sizeof(Elf_Rel);
+  }
+
+  typedef iterator_range<const Elf_Rel *> Elf_Rel_Range;
+  Elf_Rel_Range rels(const Elf_Shdr *Sec) const {
+    return make_range(rel_begin(Sec), rel_end(Sec));
   }
 
   /// \brief Iterate over program header table.
-  typedef ELFEntityIterator<const Elf_Phdr> Elf_Phdr_Iter;
+  const Elf_Phdr *program_header_begin() const {
+    if (Header->e_phnum && Header->e_phentsize != sizeof(Elf_Phdr))
+      report_fatal_error("Invalid program header size");
+    return reinterpret_cast<const Elf_Phdr *>(base() + Header->e_phoff);
+  }
 
-  Elf_Phdr_Iter program_header_begin() const {
-    return Elf_Phdr_Iter(Header->e_phentsize,
-                         (const char*)base() + Header->e_phoff);
+  const Elf_Phdr *program_header_end() const {
+    return program_header_begin() + Header->e_phnum;
   }
 
-  Elf_Phdr_Iter program_header_end() const {
-    return Elf_Phdr_Iter(Header->e_phentsize,
-                         (const char*)base() +
-                           Header->e_phoff +
-                           (Header->e_phnum * Header->e_phentsize));
+  typedef iterator_range<const Elf_Phdr *> Elf_Phdr_Range;
+
+  const Elf_Phdr_Range program_headers() const {
+    return make_range(program_header_begin(), program_header_end());
   }
 
   uint64_t getNumSections() const;
   uintX_t getStringTableIndex() const;
   ELF::Elf64_Word getExtendedSymbolTableIndex(const Elf_Sym *symb) const;
   const Elf_Ehdr *getHeader() const { return Header; }
-  const Elf_Shdr *getSection(const Elf_Sym *symb) const;
-  const Elf_Shdr *getSection(uint32_t Index) const;
+  ErrorOr<const Elf_Shdr *> getSection(const Elf_Sym *symb) const;
+  ErrorOr<const Elf_Shdr *> getSection(uint32_t Index) const;
   const Elf_Sym *getSymbol(uint32_t index) const;
 
   ErrorOr<StringRef> getStaticSymbolName(const Elf_Sym *Symb) const;
@@ -367,7 +390,6 @@ public:
   ErrorOr<StringRef> getSymbolName(const Elf_Sym *Symb, bool IsDynamic) const;
 
   ErrorOr<StringRef> getSectionName(const Elf_Shdr *Section) const;
-  uint64_t getSymbolIndex(const Elf_Sym *sym) const;
   ErrorOr<ArrayRef<uint8_t> > getSectionContents(const Elf_Shdr *Sec) const;
   StringRef getLoadName() const;
 };
@@ -439,7 +461,7 @@ void ELFFile<ELFT>::LoadVersionNeeds(const Elf_Shdr *sec) const {
 template <class ELFT>
 void ELFFile<ELFT>::LoadVersionMap() const {
   // If there is no dynamic symtab or version table, there is nothing to do.
-  if (!DynSymRegion.Addr || !dot_gnu_version_sec)
+  if (!DotDynSymSec || !dot_gnu_version_sec)
     return;
 
   // Has the VersionMap already been loaded?
@@ -466,11 +488,12 @@ ELFFile<ELFT>::getExtendedSymbolTableIndex(const Elf_Sym *symb) const {
 }
 
 template <class ELFT>
-const typename ELFFile<ELFT>::Elf_Shdr *
+ErrorOr<const typename ELFFile<ELFT>::Elf_Shdr *>
 ELFFile<ELFT>::getSection(const Elf_Sym *symb) const {
-  if (symb->st_shndx == ELF::SHN_XINDEX)
+  uint32_t Index = symb->st_shndx;
+  if (Index == ELF::SHN_XINDEX)
     return getSection(ExtendedSymbolTable.lookup(symb));
-  if (symb->st_shndx >= ELF::SHN_LORESERVE)
+  if (Index == ELF::SHN_UNDEF || Index >= ELF::SHN_LORESERVE)
     return nullptr;
   return getSection(symb->st_shndx);
 }
@@ -533,7 +556,10 @@ std::pair<const typename ELFFile<ELFT>::Elf_Shdr *,
 ELFFile<ELFT>::getRelocationSymbol(const Elf_Shdr *Sec, const RelT *Rel) const {
   if (!Sec->sh_link)
     return std::make_pair(nullptr, nullptr);
-  const Elf_Shdr *SymTable = getSection(Sec->sh_link);
+  ErrorOr<const Elf_Shdr *> SymTableOrErr = getSection(Sec->sh_link);
+  if (std::error_code EC = SymTableOrErr.getError())
+    report_fatal_error(EC.message());
+  const Elf_Shdr *SymTable = *SymTableOrErr;
   return std::make_pair(
       SymTable, getEntry<Elf_Sym>(SymTable, Rel->getSymbol(isMips64EL())));
 }
@@ -561,10 +587,7 @@ typename ELFFile<ELFT>::uintX_t ELFFile<ELFT>::getStringTableIndex() const {
 
 template <class ELFT>
 ELFFile<ELFT>::ELFFile(StringRef Object, std::error_code &EC)
-    : Buf(Object), SectionHeaderTable(nullptr), dot_symtab_sec(nullptr),
-      SymbolTableSectionHeaderIndex(nullptr), dot_gnu_version_sec(nullptr),
-      dot_gnu_version_r_sec(nullptr), dot_gnu_version_d_sec(nullptr),
-      dt_soname(nullptr) {
+    : Buf(Object) {
   const uint64_t FileSize = Buf.size();
 
   if (sizeof(Elf_Ehdr) > FileSize) {
@@ -575,8 +598,10 @@ ELFFile<ELFT>::ELFFile(StringRef Object, std::error_code &EC)
 
   Header = reinterpret_cast<const Elf_Ehdr *>(base());
 
-  if (Header->e_shoff == 0)
+  if (Header->e_shoff == 0) {
+    scanDynamicTable();
     return;
+  }
 
   const uint64_t SectionTableOffset = Header->e_shoff;
 
@@ -601,6 +626,13 @@ ELFFile<ELFT>::ELFFile(StringRef Object, std::error_code &EC)
 
   for (const Elf_Shdr &Sec : sections()) {
     switch (Sec.sh_type) {
+    case ELF::SHT_HASH:
+      if (HashTable) {
+        EC = object_error::parse_failed;
+        return;
+      }
+      HashTable = reinterpret_cast<const Elf_Hash *>(base() + Sec.sh_offset);
+      break;
     case ELF::SHT_SYMTAB_SHNDX:
       if (SymbolTableSectionHeaderIndex) {
         // More than one .symtab_shndx!
@@ -616,36 +648,23 @@ ELFFile<ELFT>::ELFFile(StringRef Object, std::error_code &EC)
         return;
       }
       dot_symtab_sec = &Sec;
-      ErrorOr<StringRef> SymtabOrErr = getStringTable(getSection(Sec.sh_link));
+      ErrorOr<const Elf_Shdr *> SectionOrErr = getSection(Sec.sh_link);
+      if ((EC = SectionOrErr.getError()))
+        return;
+      ErrorOr<StringRef> SymtabOrErr = getStringTable(*SectionOrErr);
       if ((EC = SymtabOrErr.getError()))
         return;
       DotStrtab = *SymtabOrErr;
     } break;
     case ELF::SHT_DYNSYM: {
-      if (DynSymRegion.Addr) {
+      if (DotDynSymSec) {
         // More than one .dynsym!
         EC = object_error::parse_failed;
         return;
       }
-      DynSymRegion.Addr = base() + Sec.sh_offset;
-      DynSymRegion.Size = Sec.sh_size;
-      DynSymRegion.EntSize = Sec.sh_entsize;
-      const Elf_Shdr *DynStr = getSection(Sec.sh_link);
-      DynStrRegion.Addr = base() + DynStr->sh_offset;
-      DynStrRegion.Size = DynStr->sh_size;
-      DynStrRegion.EntSize = DynStr->sh_entsize;
+      DotDynSymSec = &Sec;
       break;
     }
-    case ELF::SHT_DYNAMIC:
-      if (DynamicRegion.Addr) {
-        // More than one .dynamic!
-        EC = object_error::parse_failed;
-        return;
-      }
-      DynamicRegion.Addr = base() + Sec.sh_offset;
-      DynamicRegion.Size = Sec.sh_size;
-      DynamicRegion.EntSize = Sec.sh_entsize;
-      break;
     case ELF::SHT_GNU_versym:
       if (dot_gnu_version_sec != nullptr) {
         // More than one .gnu.version section!
@@ -674,8 +693,11 @@ ELFFile<ELFT>::ELFFile(StringRef Object, std::error_code &EC)
   }
 
   // Get string table sections.
-  ErrorOr<StringRef> SymtabOrErr =
-      getStringTable(getSection(getStringTableIndex()));
+  ErrorOr<const Elf_Shdr *> StrTabSecOrErr = getSection(getStringTableIndex());
+  if ((EC = StrTabSecOrErr.getError()))
+    return;
+
+  ErrorOr<StringRef> SymtabOrErr = getStringTable(*StrTabSecOrErr);
   if ((EC = SymtabOrErr.getError()))
     return;
   DotShstrtab = *SymtabOrErr;
@@ -691,76 +713,82 @@ ELFFile<ELFT>::ELFFile(StringRef Object, std::error_code &EC)
     }
   }
 
-  // Scan program headers.
-  for (Elf_Phdr_Iter PhdrI = program_header_begin(),
-                     PhdrE = program_header_end();
-       PhdrI != PhdrE; ++PhdrI) {
-    if (PhdrI->p_type == ELF::PT_DYNAMIC) {
-      DynamicRegion.Addr = base() + PhdrI->p_offset;
-      DynamicRegion.Size = PhdrI->p_filesz;
-      DynamicRegion.EntSize = sizeof(Elf_Dyn);
-      break;
+  scanDynamicTable();
+
+  EC = std::error_code();
+}
+
+template <class ELFT>
+static bool compareAddr(uint64_t VAddr, const Elf_Phdr_Impl<ELFT> *Phdr) {
+  return VAddr < Phdr->p_vaddr;
+}
+
+template <class ELFT> void ELFFile<ELFT>::scanDynamicTable() {
+  SmallVector<const Elf_Phdr *, 4> LoadSegments;
+  for (const Elf_Phdr &Phdr : program_headers()) {
+    if (Phdr.p_type == ELF::PT_DYNAMIC) {
+      DynamicRegion.Addr = base() + Phdr.p_offset;
+      DynamicRegion.Size = Phdr.p_filesz;
+      continue;
     }
+    if (Phdr.p_type != ELF::PT_LOAD || Phdr.p_filesz == 0)
+      continue;
+    LoadSegments.push_back(&Phdr);
   }
 
-  // Scan dynamic table.
-  for (Elf_Dyn_Iter DynI = dynamic_table_begin(), DynE = dynamic_table_end();
-       DynI != DynE; ++DynI) {
-    switch (DynI->d_tag) {
-    case ELF::DT_RELA: {
-      uint64_t VBase = 0;
-      const uint8_t *FBase = nullptr;
-      for (Elf_Phdr_Iter PhdrI = program_header_begin(),
-                         PhdrE = program_header_end();
-           PhdrI != PhdrE; ++PhdrI) {
-        if (PhdrI->p_type != ELF::PT_LOAD)
-          continue;
-        if (DynI->getPtr() >= PhdrI->p_vaddr &&
-            DynI->getPtr() < PhdrI->p_vaddr + PhdrI->p_memsz) {
-          VBase = PhdrI->p_vaddr;
-          FBase = base() + PhdrI->p_offset;
-          break;
-        }
-      }
-      if (!VBase)
-        return;
-      DynRelaRegion.Addr = FBase + DynI->getPtr() - VBase;
+  auto toMappedAddr = [&](uint64_t VAddr) -> const uint8_t * {
+    const Elf_Phdr **I = std::upper_bound(
+        LoadSegments.begin(), LoadSegments.end(), VAddr, compareAddr<ELFT>);
+    if (I == LoadSegments.begin())
+      report_fatal_error("Virtual address is not in any segment");
+    --I;
+    const Elf_Phdr &Phdr = **I;
+    uint64_t Delta = VAddr - Phdr.p_vaddr;
+    if (Delta >= Phdr.p_filesz)
+      report_fatal_error("Virtual address is not in any segment");
+    return this->base() + Phdr.p_offset + Delta;
+  };
+
+  for (const Elf_Dyn &Dyn : dynamic_table()) {
+    switch (Dyn.d_tag) {
+    case ELF::DT_HASH:
+      if (HashTable)
+        continue;
+      HashTable =
+          reinterpret_cast<const Elf_Hash *>(toMappedAddr(Dyn.getPtr()));
+      break;
+    case ELF::DT_STRTAB:
+      if (!DynStrRegion.Addr)
+        DynStrRegion.Addr = toMappedAddr(Dyn.getPtr());
+      break;
+    case ELF::DT_STRSZ:
+      if (!DynStrRegion.Size)
+        DynStrRegion.Size = Dyn.getVal();
+      break;
+    case ELF::DT_RELA:
+      if (!DynRelaRegion.Addr)
+        DynRelaRegion.Addr = toMappedAddr(Dyn.getPtr());
       break;
-    }
     case ELF::DT_RELASZ:
-      DynRelaRegion.Size = DynI->getVal();
+      DynRelaRegion.Size = Dyn.getVal();
       break;
     case ELF::DT_RELAENT:
-      DynRelaRegion.EntSize = DynI->getVal();
+      DynRelaRegion.EntSize = Dyn.getVal();
     }
   }
-
-  EC = std::error_code();
 }
 
-// Get the symbol table index in the symtab section given a symbol
 template <class ELFT>
-uint64_t ELFFile<ELFT>::getSymbolIndex(const Elf_Sym *Sym) const {
-  uintptr_t SymLoc = uintptr_t(Sym);
-  uintptr_t SymTabLoc = uintptr_t(base() + dot_symtab_sec->sh_offset);
-  assert(SymLoc > SymTabLoc && "Symbol not in symbol table!");
-  uint64_t SymOffset = SymLoc - SymTabLoc;
-  assert(SymOffset % dot_symtab_sec->sh_entsize == 0 &&
-         "Symbol not multiple of symbol size!");
-  return SymOffset / dot_symtab_sec->sh_entsize;
+const typename ELFFile<ELFT>::Elf_Shdr *ELFFile<ELFT>::section_begin() const {
+  if (Header->e_shentsize != sizeof(Elf_Shdr))
+    report_fatal_error(
+        "Invalid section header entry size (e_shentsize) in ELF header");
+  return reinterpret_cast<const Elf_Shdr *>(base() + Header->e_shoff);
 }
 
 template <class ELFT>
-typename ELFFile<ELFT>::Elf_Shdr_Iter ELFFile<ELFT>::section_begin() const {
-  return Elf_Shdr_Iter(Header->e_shentsize,
-                       (const char *)base() + Header->e_shoff);
-}
-
-template <class ELFT>
-typename ELFFile<ELFT>::Elf_Shdr_Iter ELFFile<ELFT>::section_end() const {
-  return Elf_Shdr_Iter(Header->e_shentsize,
-                       (const char *)base() + Header->e_shoff +
-                           (getNumSections() * Header->e_shentsize));
+const typename ELFFile<ELFT>::Elf_Shdr *ELFFile<ELFT>::section_end() const {
+  return section_begin() + getNumSections();
 }
 
 template <class ELFT>
@@ -781,33 +809,19 @@ const typename ELFFile<ELFT>::Elf_Sym *ELFFile<ELFT>::symbol_end() const {
 }
 
 template <class ELFT>
-typename ELFFile<ELFT>::Elf_Dyn_Iter
+const typename ELFFile<ELFT>::Elf_Dyn *
 ELFFile<ELFT>::dynamic_table_begin() const {
-  if (DynamicRegion.Addr)
-    return Elf_Dyn_Iter(DynamicRegion.EntSize,
-                        (const char *)DynamicRegion.Addr);
-  return Elf_Dyn_Iter(0, nullptr);
+  return reinterpret_cast<const Elf_Dyn *>(DynamicRegion.Addr);
 }
 
 template <class ELFT>
-typename ELFFile<ELFT>::Elf_Dyn_Iter
-ELFFile<ELFT>::dynamic_table_end(bool NULLEnd) const {
-  if (!DynamicRegion.Addr)
-    return Elf_Dyn_Iter(0, nullptr);
-  Elf_Dyn_Iter Ret(DynamicRegion.EntSize,
-                    (const char *)DynamicRegion.Addr + DynamicRegion.Size);
+const typename ELFFile<ELFT>::Elf_Dyn *
+ELFFile<ELFT>::dynamic_table_end() const {
+  uint64_t Size = DynamicRegion.Size;
+  if (Size % sizeof(Elf_Dyn))
+    report_fatal_error("Invalid dynamic table size");
 
-  if (NULLEnd) {
-    Elf_Dyn_Iter Start = dynamic_table_begin();
-    while (Start != Ret && Start->getTag() != ELF::DT_NULL)
-      ++Start;
-
-    // Include the DT_NULL.
-    if (Start != Ret)
-      ++Start;
-    Ret = Start;
-  }
-  return Ret;
+  return dynamic_table_begin() + Size / sizeof(Elf_Dyn);
 }
 
 template <class ELFT>
@@ -827,7 +841,10 @@ StringRef ELFFile<ELFT>::getLoadName() const {
 template <class ELFT>
 template <typename T>
 const T *ELFFile<ELFT>::getEntry(uint32_t Section, uint32_t Entry) const {
-  return getEntry<T>(getSection(Section), Entry);
+  ErrorOr<const Elf_Shdr *> Sec = getSection(Section);
+  if (std::error_code EC = Sec.getError())
+    report_fatal_error(EC.message());
+  return getEntry<T>(*Sec, Entry);
 }
 
 template <class ELFT>
@@ -839,17 +856,15 @@ const T *ELFFile<ELFT>::getEntry(const Elf_Shdr *Section,
 }
 
 template <class ELFT>
-const typename ELFFile<ELFT>::Elf_Shdr *
-ELFFile<ELFT>::getSection(uint32_t index) const {
-  if (index == 0)
-    return nullptr;
-  if (!SectionHeaderTable || index >= getNumSections())
-    // FIXME: Proper error handling.
-    report_fatal_error("Invalid section index!");
+ErrorOr<const typename ELFFile<ELFT>::Elf_Shdr *>
+ELFFile<ELFT>::getSection(uint32_t Index) const {
+  assert(SectionHeaderTable && "SectionHeaderTable not initialized!");
+  if (Index >= getNumSections())
+    return object_error::invalid_section_index;
 
   return reinterpret_cast<const Elf_Shdr *>(
-         reinterpret_cast<const char *>(SectionHeaderTable)
-         + (index * Header->e_shentsize));
+      reinterpret_cast<const char *>(SectionHeaderTable) +
+      (Index * Header->e_shentsize));
 }
 
 template <class ELFT>
@@ -869,7 +884,7 @@ ELFFile<ELFT>::getStringTable(const Elf_Shdr *Section) const {
 
 template <class ELFT>
 const char *ELFFile<ELFT>::getDynamicString(uintX_t Offset) const {
-  if (!DynStrRegion.Addr || Offset >= DynStrRegion.Size)
+  if (Offset >= DynStrRegion.Size)
     return nullptr;
   return (const char *)DynStrRegion.Addr + Offset;
 }
@@ -915,7 +930,7 @@ ErrorOr<StringRef> ELFFile<ELFT>::getSymbolVersion(const Elf_Shdr *section,
     StrTab = *StrTabOrErr;
   }
   // Handle non-dynamic symbols.
-  if (section != DynSymRegion.Addr && section != nullptr) {
+  if (section != DotDynSymSec && section != nullptr) {
     // Non-dynamic symbols can have versions in their names
     // A name of the form 'foo@V1' indicates version 'V1', non-default.
     // A name of the form 'foo@@V2' indicates version 'V2', default version.
@@ -946,8 +961,10 @@ ErrorOr<StringRef> ELFFile<ELFT>::getSymbolVersion(const Elf_Shdr *section,
   }
 
   // Determine the position in the symbol table of this entry.
-  size_t entry_index = ((const char *)symb - (const char *)DynSymRegion.Addr) /
-                       DynSymRegion.EntSize;
+  size_t entry_index =
+      (reinterpret_cast<uintptr_t>(symb) - DotDynSymSec->sh_offset -
+       reinterpret_cast<uintptr_t>(base())) /
+      sizeof(Elf_Sym);
 
   // Get the corresponding version index entry
   const Elf_Versym *vs = getEntry<Elf_Versym>(dot_gnu_version_sec, entry_index);