[llvm] r241765 - [Object][ELF] Support dumping hash-tables from files with no section table.

Rui Ueyama ruiu at google.com
Wed Jul 8 17:38:31 PDT 2015


Michael,

This patch doesn't seem to compile with Clang on Linux.

On Wed, Jul 8, 2015 at 5:21 PM, Michael J. Spencer <bigcheesegs at gmail.com>
wrote:

> Author: mspencer
> Date: Wed Jul  8 19:21:06 2015
> New Revision: 241765
>
> URL: http://llvm.org/viewvc/llvm-project?rev=241765&view=rev
> Log:
> [Object][ELF] Support dumping hash-tables from files with no section table.
>
> Added:
>     llvm/trunk/test/Object/Inputs/no-section-table.so
>     llvm/trunk/test/Object/no-section-table.test
> Modified:
>     llvm/trunk/include/llvm/Object/ELF.h
>     llvm/trunk/include/llvm/Object/ELFTypes.h
>     llvm/trunk/tools/llvm-readobj/ELFDumper.cpp
>     llvm/trunk/tools/llvm-readobj/ObjDumper.h
>     llvm/trunk/tools/llvm-readobj/StreamWriter.h
>     llvm/trunk/tools/llvm-readobj/llvm-readobj.cpp
>
> Modified: llvm/trunk/include/llvm/Object/ELF.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Object/ELF.h?rev=241765&r1=241764&r2=241765&view=diff
>
> ==============================================================================
> --- llvm/trunk/include/llvm/Object/ELF.h (original)
> +++ llvm/trunk/include/llvm/Object/ELF.h Wed Jul  8 19:21:06 2015
> @@ -16,6 +16,7 @@
>
>  #include "llvm/ADT/ArrayRef.h"
>  #include "llvm/ADT/DenseMap.h"
> +#include "llvm/ADT/IntervalMap.h"
>  #include "llvm/ADT/PointerIntPair.h"
>  #include "llvm/ADT/SmallVector.h"
>  #include "llvm/ADT/StringSwitch.h"
> @@ -139,6 +140,7 @@ public:
>    typedef Elf_Verneed_Impl<ELFT> Elf_Verneed;
>    typedef Elf_Vernaux_Impl<ELFT> Elf_Vernaux;
>    typedef Elf_Versym_Impl<ELFT> Elf_Versym;
> +  typedef Elf_Hash<ELFT> Elf_Hash;
>    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;
> @@ -176,6 +178,7 @@ private:
>    const Elf_Shdr *dot_symtab_sec = nullptr; // Symbol table section.
>    StringRef DynSymStrTab;                   // Dynnamic symbol string
> table.
>    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;
> @@ -229,6 +232,8 @@ 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;
> @@ -237,6 +242,7 @@ public:
>
>    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;
> @@ -578,8 +584,10 @@ ELFFile<ELFT>::ELFFile(StringRef Object,
>
>    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;
>
> @@ -604,6 +612,13 @@ ELFFile<ELFT>::ELFFile(StringRef Object,
>
>    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!
> @@ -701,7 +716,21 @@ ELFFile<ELFT>::ELFFile(StringRef Object,
>      }
>    }
>
> -  // Scan program headers.
> +  scanDynamicTable();
> +
> +  EC = std::error_code();
> +}
> +
> +template <class ELFT>
> +void ELFFile<ELFT>::scanDynamicTable() {
> +  // Build load-address to file-offset map.
> +  typedef typename IntervalMap<
> +      uintX_t, uintptr_t,
> +      IntervalMapImpl::NodeSizer<uintX_t, uintptr_t>::LeafSize,
> +      IntervalMapHalfOpenInfo<uintX_t>> LoadMapT;
> +  LoadMapT::Allocator Alloc;
> +  LoadMapT LoadMap(Alloc);
> +
>    for (Elf_Phdr_Iter PhdrI = program_header_begin(),
>                       PhdrE = program_header_end();
>         PhdrI != PhdrE; ++PhdrI) {
> @@ -709,34 +738,36 @@ ELFFile<ELFT>::ELFFile(StringRef Object,
>        DynamicRegion.Addr = base() + PhdrI->p_offset;
>        DynamicRegion.Size = PhdrI->p_filesz;
>        DynamicRegion.EntSize = sizeof(Elf_Dyn);
> -      break;
> +      continue;
>      }
> +    if (PhdrI->p_type != ELF::PT_LOAD)
> +      continue;
> +    if (PhdrI->p_filesz == 0)
> +      continue;
> +    LoadMap.insert(PhdrI->p_vaddr, PhdrI->p_vaddr + PhdrI->p_filesz,
> +                   PhdrI->p_offset);
>    }
>
> -  // Scan dynamic table.
> +  auto toMappedAddr = [&](uint64_t VAddr) -> const uint8_t * {
> +    auto I = LoadMap.find(VAddr);
> +    if (I == LoadMap.end())
> +      return nullptr;
> +    return base() + I.value() + (VAddr - I.start());
> +  };
> +
>    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;
> +    case ELF::DT_HASH:
> +      if (HashTable)
> +        continue;
> +      HashTable =
> +          reinterpret_cast<const Elf_Hash
> *>(toMappedAddr(DynI->getPtr()));
> +      break;
> +    case ELF::DT_RELA:
> +      if (!DynRelaRegion.Addr)
> +        DynRelaRegion.Addr = toMappedAddr(DynI->getPtr());
>        break;
> -    }
>      case ELF::DT_RELASZ:
>        DynRelaRegion.Size = DynI->getVal();
>        break;
> @@ -744,8 +775,6 @@ ELFFile<ELFT>::ELFFile(StringRef Object,
>        DynRelaRegion.EntSize = DynI->getVal();
>      }
>    }
> -
> -  EC = std::error_code();
>  }
>
>  template <class ELFT>
>
> Modified: llvm/trunk/include/llvm/Object/ELFTypes.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Object/ELFTypes.h?rev=241765&r1=241764&r2=241765&view=diff
>
> ==============================================================================
> --- llvm/trunk/include/llvm/Object/ELFTypes.h (original)
> +++ llvm/trunk/include/llvm/Object/ELFTypes.h Wed Jul  8 19:21:06 2015
> @@ -10,6 +10,7 @@
>  #ifndef LLVM_OBJECT_ELFTYPES_H
>  #define LLVM_OBJECT_ELFTYPES_H
>
> +#include "llvm/ADT/ArrayRef.h"
>  #include "llvm/Object/Error.h"
>  #include "llvm/Support/DataTypes.h"
>  #include "llvm/Support/ELF.h"
> @@ -463,6 +464,23 @@ struct Elf_Phdr_Impl<ELFType<TargetEndia
>    Elf_Xword p_align;  // Segment alignment constraint
>  };
>
> +// ELFT needed for endianess.
> +template <class ELFT>
> +struct Elf_Hash {
> +  LLVM_ELF_IMPORT_TYPES_ELFT(ELFT);
> +  Elf_Word nbucket;
> +  Elf_Word nchain;
> +
> +  ArrayRef<const Elf_Word> buckets() const {
> +    return ArrayRef<const Elf_Word>(&nbucket + 2, &nbucket + 2 + nbucket);
> +  }
> +
> +  ArrayRef<const Elf_Word> chains() const {
> +    return ArrayRef<const Elf_Word>(&nbucket + 2 + nbucket,
> +                                    &nbucket + 2 + nbucket + nchain);
> +  }
> +};
> +
>  // MIPS .reginfo section
>  template <class ELFT>
>  struct Elf_Mips_RegInfo;
>
> Added: llvm/trunk/test/Object/Inputs/no-section-table.so
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Object/Inputs/no-section-table.so?rev=241765&view=auto
>
> ==============================================================================
> Binary files llvm/trunk/test/Object/Inputs/no-section-table.so (added) and
> llvm/trunk/test/Object/Inputs/no-section-table.so Wed Jul  8 19:21:06 2015
> differ
>
> Added: llvm/trunk/test/Object/no-section-table.test
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Object/no-section-table.test?rev=241765&view=auto
>
> ==============================================================================
> --- llvm/trunk/test/Object/no-section-table.test (added)
> +++ llvm/trunk/test/Object/no-section-table.test Wed Jul  8 19:21:06 2015
> @@ -0,0 +1,8 @@
> +RUN: llvm-readobj %p/Inputs/no-section-table.so -hash-table | FileCheck %s
> +
> +CHECK: HashTable {
> +CHECK:   Num Buckets: 3
> +CHECK:   Num Chains: 13
> +CHECK:   Buckets: [12, 10, 11]
> +CHECK:   Chains: [0, 0, 0, 0, 2, 3, 4, 0, 7, 5, 6, 8, 9]
> +CHECK: }
>
> Modified: llvm/trunk/tools/llvm-readobj/ELFDumper.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-readobj/ELFDumper.cpp?rev=241765&r1=241764&r2=241765&view=diff
>
> ==============================================================================
> --- llvm/trunk/tools/llvm-readobj/ELFDumper.cpp (original)
> +++ llvm/trunk/tools/llvm-readobj/ELFDumper.cpp Wed Jul  8 19:21:06 2015
> @@ -56,6 +56,7 @@ public:
>    void printDynamicTable() override;
>    void printNeededLibraries() override;
>    void printProgramHeaders() override;
> +  void printHashTable() override;
>
>    void printAttributes() override;
>    void printMipsPLTGOT() override;
> @@ -1119,6 +1120,18 @@ void ELFDumper<ELFT>::printProgramHeader
>    }
>  }
>
> +template <typename ELFT>
> +void ELFDumper<ELFT>::printHashTable() {
> +  DictScope D(W, "HashTable");
> +  auto HT = Obj->getHashTable();
> +  if (!HT)
> +    return;
> +  W.printNumber("Num Buckets", HT->nbucket);
> +  W.printNumber("Num Chains", HT->nchain);
> +  W.printList("Buckets", HT->buckets());
> +  W.printList("Chains", HT->chains());
> +}
> +
>  template <class ELFT>
>  void ELFDumper<ELFT>::printAttributes() {
>    W.startLine() << "Attributes not implemented.\n";
>
> Modified: llvm/trunk/tools/llvm-readobj/ObjDumper.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-readobj/ObjDumper.h?rev=241765&r1=241764&r2=241765&view=diff
>
> ==============================================================================
> --- llvm/trunk/tools/llvm-readobj/ObjDumper.h (original)
> +++ llvm/trunk/tools/llvm-readobj/ObjDumper.h Wed Jul  8 19:21:06 2015
> @@ -37,6 +37,7 @@ public:
>    virtual void printDynamicTable() { }
>    virtual void printNeededLibraries() { }
>    virtual void printProgramHeaders() { }
> +  virtual void printHashTable() { }
>
>    // Only implemented for ARM ELF at this time.
>    virtual void printAttributes() { }
>
> Modified: llvm/trunk/tools/llvm-readobj/StreamWriter.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-readobj/StreamWriter.h?rev=241765&r1=241764&r2=241765&view=diff
>
> ==============================================================================
> --- llvm/trunk/tools/llvm-readobj/StreamWriter.h (original)
> +++ llvm/trunk/tools/llvm-readobj/StreamWriter.h Wed Jul  8 19:21:06 2015
> @@ -181,8 +181,8 @@ public:
>      startLine() << Label << ": " << (Value ? "Yes" : "No") << '\n';
>    }
>
> -  template <typename T_>
> -  void printList(StringRef Label, const SmallVectorImpl<T_> &List) {
> +  template <typename T>
> +  void printList(StringRef Label, const T &List) {
>      startLine() << Label << ": [";
>      bool Comma = false;
>      for (const auto &Item : List) {
>
> Modified: llvm/trunk/tools/llvm-readobj/llvm-readobj.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-readobj/llvm-readobj.cpp?rev=241765&r1=241764&r2=241765&view=diff
>
> ==============================================================================
> --- llvm/trunk/tools/llvm-readobj/llvm-readobj.cpp (original)
> +++ llvm/trunk/tools/llvm-readobj/llvm-readobj.cpp Wed Jul  8 19:21:06 2015
> @@ -127,6 +127,10 @@ namespace opts {
>    cl::opt<bool> ProgramHeaders("program-headers",
>      cl::desc("Display ELF program headers"));
>
> +  // -hash-table
> +  cl::opt<bool> HashTable("hash-table",
> +    cl::desc("Display ELF hash table"));
> +
>    // -expand-relocs
>    cl::opt<bool> ExpandRelocs("expand-relocs",
>      cl::desc("Expand each shown relocation to multiple lines"));
> @@ -300,6 +304,8 @@ static void dumpObject(const ObjectFile
>      Dumper->printNeededLibraries();
>    if (opts::ProgramHeaders)
>      Dumper->printProgramHeaders();
> +  if (opts::HashTable)
> +    Dumper->printHashTable();
>    if (Obj->getArch() == llvm::Triple::arm && Obj->isELF())
>      if (opts::ARMAttributes)
>        Dumper->printAttributes();
>
>
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