Re: [PATCH 7/8] abg-elf-helpers: migrate more elf helpers (architecture specific helpers)

[Giuliano Procida <gprocida@google.com>]

Hi.

On Mon, 20 Apr 2020 at 12:09, Matthias Maennich <maennich@google.com> wrote:
>
> This migrates more architecture specific helpers over to the
> elf-helpers. No functional change intended.
>
> Signed-off-by: Matthias Maennich <maennich@google.com>

Stray line.

>         * src/abg-dwarf-reader.cc(elf_architecture_is_ppc64): Move
>         function out and adjust callers to call the migrated
>         functions.
>         (elf_architecture_is_big_endian): Likewise.
>         (architecture_word_size): Likewise.
>         (current_elf_file_is_executable): Likewise.
>         (current_elf_file_is_dso): Likewise.
>         * src/abg-elf-helpers.cc (architecture_is_ppc64): Add new function.
>         (architecture_is_big_endian): Likewise.
>         (get_architecture_word_size): Likewise.
>         (is_executable): Likewise.
>         (is_dso): Likewise.
>         * src/abg-elf-helpers.h (architecture_is_ppc64): Add new declaration.
>         (architecture_is_big_endian): Likewise.
>         (get_architecture_word_size): Likewise.
>         (is_executable): Likewise.
>         (is_dso): Likewise.

Reviewed-by: Giuliano Procida <gprocida@google.com>


> Signed-off-by: Matthias Maennich <maennich@google.com>
> ---
>  src/abg-dwarf-reader.cc | 91 ++++-------------------------------------
>  src/abg-elf-helpers.cc  | 79 +++++++++++++++++++++++++++++++++++
>  src/abg-elf-helpers.h   | 18 ++++++++
>  3 files changed, 106 insertions(+), 82 deletions(-)
>
> diff --git a/src/abg-dwarf-reader.cc b/src/abg-dwarf-reader.cc
> index 56da03a60940..dc3332410b1e 100644
> --- a/src/abg-dwarf-reader.cc
> +++ b/src/abg-dwarf-reader.cc
> @@ -5700,10 +5700,10 @@ public:
>      if (!elf_handle())
>        return fn_desc_address;
>
> -    if (!elf_architecture_is_ppc64())
> +    if (!architecture_is_ppc64(elf_handle()))
>        return fn_desc_address;
>
> -    bool is_big_endian = elf_architecture_is_big_endian();
> +    bool is_big_endian = architecture_is_big_endian(elf_handle());
>
>      Elf_Scn *opd_section = find_opd_section();
>      if (!opd_section)
> @@ -5979,7 +5979,7 @@ public:
>    {
>      if (!fun_entry_addr_sym_map_ && !fun_addr_sym_map_)
>        maybe_load_symbol_maps();
> -    if (elf_architecture_is_ppc64())
> +    if (architecture_is_ppc64(elf_handle()))
>        return fun_entry_addr_sym_map_;
>      return fun_addr_sym_map_;
>    }
> @@ -6335,79 +6335,6 @@ public:
>    elf_architecture() const
>    {return elf_architecture_;}
>
> -  /// Return the size of a word for the current architecture.
> -  /// @return the size of a word.
> -  unsigned char
> -  architecture_word_size() const
> -  {
> -    unsigned char word_size = 0;
> -    GElf_Ehdr eh_mem;
> -    GElf_Ehdr* elf_header = gelf_getehdr(elf_handle(), &eh_mem);
> -    if (elf_header->e_ident[EI_CLASS] == ELFCLASS32)
> -      word_size = 4;
> -    else if (elf_header->e_ident[EI_CLASS] == ELFCLASS64)
> -      word_size = 8;
> -    else
> -      ABG_ASSERT_NOT_REACHED;
> -    return word_size;
> -  }
> -
> -  /// Test if the architecture of the current binary is ppc64.
> -  ///
> -  /// @return true iff the architecture of the current binary is ppc64.
> -  bool
> -  elf_architecture_is_ppc64() const
> -  {
> -    GElf_Ehdr eh_mem;
> -    GElf_Ehdr* elf_header = gelf_getehdr(elf_handle(), &eh_mem);
> -
> -    return (elf_header && elf_header->e_machine == EM_PPC64);
> -  }
> -
> -  /// Test if the endianness of the current binary is Big Endian.
> -  ///
> -  /// https://en.wikipedia.org/wiki/Endianness.
> -  ///
> -  /// @return true iff the current binary is Big Endian.
> -  bool
> -  elf_architecture_is_big_endian() const
> -  {
> -    GElf_Ehdr eh_mem;
> -    GElf_Ehdr* elf_header = gelf_getehdr(elf_handle(), &eh_mem);
> -
> -    bool is_big_endian = (elf_header->e_ident[EI_DATA] == ELFDATA2MSB);
> -
> -    if (!is_big_endian)
> -      ABG_ASSERT(elf_header->e_ident[EI_DATA] == ELFDATA2LSB);
> -
> -    return is_big_endian;
> -  }
> -
> -  /// Test if the current elf file being read is an executable.
> -  ///
> -  /// @return true iff the current elf file being read is an
> -  /// executable.
> -  bool
> -  current_elf_file_is_executable() const
> -  {
> -    GElf_Ehdr eh_mem;
> -    GElf_Ehdr* elf_header = gelf_getehdr(elf_handle(), &eh_mem);
> -    return elf_header->e_type == ET_EXEC;
> -  }
> -
> -  /// Test if the current elf file being read is a dynamic shared
> -  /// object.
> -  ///
> -  /// @return true iff the current elf file being read is a
> -  /// dynamic shared object.
> -  bool
> -  current_elf_file_is_dso() const
> -  {
> -    GElf_Ehdr eh_mem;
> -    GElf_Ehdr* elf_header = gelf_getehdr(elf_handle(), &eh_mem);
> -    return elf_header->e_type == ET_DYN;
> -  }
> -
>    /// Getter for the map of global variables symbol address -> global
>    /// variable symbol index.
>    ///
> @@ -6471,7 +6398,7 @@ public:
>      GElf_Ehdr elf_header;
>      ABG_ASSERT(gelf_getehdr(elf_handle(), &elf_header));
>
> -    bool is_ppc64 = elf_architecture_is_ppc64();
> +    bool is_ppc64 = architecture_is_ppc64(elf_handle());
>
>      for (size_t i = 0; i < nb_syms; ++i)
>        {
> @@ -6688,7 +6615,7 @@ public:
>    {
>      Elf_Data*      elf_data = elf_rawdata(section, 0);
>      uint8_t*       bytes = reinterpret_cast<uint8_t*>(elf_data->d_buf);
> -    bool           is_big_endian = elf_architecture_is_big_endian();
> +    bool           is_big_endian = architecture_is_big_endian(elf_handle());
>      elf_symbol_sptr symbol;
>      GElf_Addr      symbol_address = 0;
>
> @@ -6696,7 +6623,7 @@ public:
>      if (position_relative_relocations)
>        symbol_value_size = sizeof(int32_t);
>      else
> -      symbol_value_size = architecture_word_size();
> +      symbol_value_size = get_architecture_word_size(elf_handle());
>
>      const int read_offset = (symbol_offset * symbol_value_size);
>      bytes += read_offset;
> @@ -6886,7 +6813,7 @@ public:
>      if (format == UNDEFINED_KSYMTAB_FORMAT)
>        ;
>      else if (format == PRE_V4_19_KSYMTAB_FORMAT)
> -      result = architecture_word_size();
> +      result = get_architecture_word_size(elf_handle());
>      else if (format == V4_19_KSYMTAB_FORMAT)
>        result = 4;
>      else
> @@ -7065,7 +6992,7 @@ public:
>      //
>      // Lets thus walk the array of entries, and let's read just the
>      // symbol address part of each entry.
> -    bool is_big_endian = elf_architecture_is_big_endian();
> +    bool is_big_endian = architecture_is_big_endian(elf_handle());
>      elf_symbol_sptr symbol;
>      unsigned char symbol_value_size = get_ksymtab_symbol_value_size();
>
> @@ -7367,7 +7294,7 @@ public:
>      if (!fun_addr_sym_map_)
>        fun_addr_sym_map_.reset(new addr_elf_symbol_sptr_map_type);
>
> -    if (!fun_entry_addr_sym_map_ && elf_architecture_is_ppc64())
> +    if (!fun_entry_addr_sym_map_ && architecture_is_ppc64(elf_handle()))
>        fun_entry_addr_sym_map_.reset(new addr_elf_symbol_sptr_map_type);
>
>      if (!var_syms_)
> diff --git a/src/abg-elf-helpers.cc b/src/abg-elf-helpers.cc
> index b77440206fb0..895feb6f7768 100644
> --- a/src/abg-elf-helpers.cc
> +++ b/src/abg-elf-helpers.cc
> @@ -829,6 +829,40 @@ get_version_for_symbol(Elf*                        elf_handle,
>    return false;
>  }
>
> +/// Test if the architecture of the current binary is ppc64.
> +///
> +/// @param elf_handle the ELF handle to consider.
> +///
> +/// @return true iff the architecture of the current binary is ppc64.
> +bool
> +architecture_is_ppc64(Elf* elf_handle)
> +{
> +  GElf_Ehdr  eh_mem;
> +  GElf_Ehdr* elf_header = gelf_getehdr(elf_handle, &eh_mem);
> +  return (elf_header && elf_header->e_machine == EM_PPC64);
> +}
> +
> +/// Test if the endianness of the current binary is Big Endian.
> +///
> +/// https://en.wikipedia.org/wiki/Endianness.
> +///
> +/// @param elf_handle the ELF handle to consider.
> +///
> +/// @return true iff the current binary is Big Endian.
> +bool
> +architecture_is_big_endian(Elf* elf_handle)
> +{
> +  GElf_Ehdr  elf_header;
> +  gelf_getehdr(elf_handle, &elf_header);
> +
> +  bool is_big_endian = (elf_header.e_ident[EI_DATA] == ELFDATA2MSB);
> +
> +  if (!is_big_endian)
> +    ABG_ASSERT(elf_header.e_ident[EI_DATA] == ELFDATA2LSB);
> +
> +  return is_big_endian;
> +}
> +
>  /// Test if the ELF binary denoted by a given ELF handle is a Linux
>  /// Kernel Module.
>  ///
> @@ -907,6 +941,51 @@ get_binary_load_address(Elf* elf_handle, GElf_Addr& load_address)
>    return false;
>  }
>
> +/// Return the size of a word for the current architecture.
> +///
> +/// @param elf_handle the ELF handle to consider.
> +///
> +/// @return the size of a word.
> +unsigned char
> +get_architecture_word_size(Elf* elf_handle)
> +{
> +  unsigned char word_size = 0;
> +  GElf_Ehdr    elf_header;
> +  gelf_getehdr(elf_handle, &elf_header);
> +  if (elf_header.e_ident[EI_CLASS] == ELFCLASS32)
> +    word_size = 4;
> +  else if (elf_header.e_ident[EI_CLASS] == ELFCLASS64)
> +    word_size = 8;
> +  else
> +    ABG_ASSERT_NOT_REACHED;
> +  return word_size;
> +}
> +
> +/// Test if the elf file being read is an executable.
> +///
> +/// @param elf_handle the ELF handle to consider.
> +///
> +/// @return true iff the elf file being read is an / executable.
> +bool
> +is_executable(Elf* elf_handle)
> +{
> +  GElf_Ehdr  elf_header;
> +  gelf_getehdr(elf_handle, &elf_header);
> +  return elf_header.e_type == ET_EXEC;
> +}
> +
> +/// Test if the elf file being read is a dynamic shared / object.
> +///
> +/// @param elf_handle the ELF handle to consider.
> +///
> +/// @return true iff the elf file being read is a / dynamic shared object.
> +bool
> +is_dso(Elf* elf_handle)
> +{
> +  GElf_Ehdr  elf_header;
> +  gelf_getehdr(elf_handle, &elf_header);
> +  return elf_header.e_type == ET_DYN;
> +}
>
>  } // end namespace elf_helpers
>  } // end namespace abigail
> diff --git a/src/abg-elf-helpers.h b/src/abg-elf-helpers.h
> index 8a83bb4f2e95..6eff245a6a30 100644
> --- a/src/abg-elf-helpers.h
> +++ b/src/abg-elf-helpers.h
> @@ -139,6 +139,15 @@ get_version_for_symbol(Elf*                        elf_handle,
>                        bool                     get_def_version,
>                        elf_symbol::version&     version);
>
> +//
> +// Architecture specific helpers
> +//
> +bool
> +architecture_is_ppc64(Elf* elf_handle);
> +
> +bool
> +architecture_is_big_endian(Elf* elf_handle);
> +
>  //
>  // Helpers for Linux Kernel Binaries
>  //
> @@ -156,6 +165,15 @@ is_linux_kernel(Elf *elf_handle);
>  bool
>  get_binary_load_address(Elf* elf_handle, GElf_Addr& load_address);
>
> +unsigned char
> +get_architecture_word_size(Elf* elf_handle);
> +
> +bool
> +is_executable(Elf* elf_handle);
> +
> +bool
> +is_dso(Elf* elf_handle);
> +
>  } // end namespace elf_helpers
>  } // end namespace abigail
>
> --
> 2.26.1.301.g55bc3eb7cb9-goog
>