[PATCH] gold: Maintain sparc ELF header bits properly

[Cary Coutant]

[cc'ing iant explicitly, in case this thread didn't make it through
his filters.]

-cary


On Mon, Apr 23, 2012 at 2:21 PM, David Miller <davem@davemloft.net> wrote:
> From: David Miller <davem@davemloft.net>
> Date: Fri, 20 Apr 2012 18:44:48 -0400 (EDT)
>
>> From: Cary Coutant <ccoutant@google.com>
>> Date: Fri, 20 Apr 2012 15:32:48 -0700
>>
>>>> It really would have been nice if I could just call down into the
>>>> default implementations after I did the sparc specific bits, but
>>>> it's not possible to just simply say:
>>>>
>>>>  this->do_make_elf_object_implementation(...)
>>>
>>> Sure it is:
>>>
>>>     Target::do_make_elf_object(name, input_file, offset, ehdr);
>>
>> Indeed, that does the trick, thanks!
>
> Ping?
>
>> gold/
>>
>>       * sparc.cc (class Target_sparc): Add elf_machine_, elf_flags_,
>>       and elf_flags_set_.
>>       (Target_sparc::Target_sparc): Initialize new fields.
>>       (Target_sparc::do_make_elf_object): New function.
>>       (Target_sparc::do_adjust_elf_header): New function.
>> ---
>>  gold/sparc.cc |  112 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
>>  1 file changed, 111 insertions(+), 1 deletion(-)
>>
>> diff --git a/gold/sparc.cc b/gold/sparc.cc
>> index 762da42..004a265 100644
>> --- a/gold/sparc.cc
>> +++ b/gold/sparc.cc
>> @@ -60,7 +60,9 @@ class Target_sparc : public Sized_target<size, big_endian>
>>      : Sized_target<size, big_endian>(&sparc_info),
>>        got_(NULL), plt_(NULL), rela_dyn_(NULL), rela_ifunc_(NULL),
>>        copy_relocs_(elfcpp::R_SPARC_COPY), dynbss_(NULL),
>> -      got_mod_index_offset_(-1U), tls_get_addr_sym_(NULL)
>> +      got_mod_index_offset_(-1U), tls_get_addr_sym_(NULL),
>> +      elf_machine_(sparc_info.machine_code), elf_flags_(0),
>> +      elf_flags_set_(false)
>>    {
>>    }
>>
>> @@ -206,6 +208,15 @@ class Target_sparc : public Sized_target<size, big_endian>
>>    unsigned int
>>    plt_entry_size() const;
>>
>> + protected:
>> +  // Make an ELF object.
>> +  Object*
>> +  do_make_elf_object(const std::string&, Input_file*, off_t,
>> +                  const elfcpp::Ehdr<size, big_endian>& ehdr);
>> +
>> +  void
>> +  do_adjust_elf_header(unsigned char* view, int len) const;
>> +
>>   private:
>>
>>    // The class which scans relocations.
>> @@ -432,6 +443,12 @@ class Target_sparc : public Sized_target<size, big_endian>
>>    unsigned int got_mod_index_offset_;
>>    // Cached pointer to __tls_get_addr symbol
>>    Symbol* tls_get_addr_sym_;
>> +  // Accumulated elf machine type
>> +  elfcpp::Elf_Half elf_machine_;
>> +  // Accumulated elf header flags
>> +  elfcpp::Elf_Word elf_flags_;
>> +  // Whether elf_flags_ has been set for the first time yet
>> +  bool elf_flags_set_;
>>  };
>>
>>  template<>
>> @@ -4071,6 +4088,99 @@ Target_sparc<size, big_endian>::do_dynsym_value(const Symbol* gsym) const
>>    return this->plt_section()->address() + gsym->plt_offset();
>>  }
>>
>> +// do_make_elf_object to override the same function in the base class.
>> +// We need to use a target-specific sub-class of
>> +// Sized_relobj_file<size, big_endian> to process SPARC specific bits
>> +// of the ELF headers.  Hence we need to have our own ELF object creation.
>> +
>> +template<int size, bool big_endian>
>> +Object*
>> +Target_sparc<size, big_endian>::do_make_elf_object(
>> +    const std::string& name,
>> +    Input_file* input_file,
>> +    off_t offset, const elfcpp::Ehdr<size, big_endian>& ehdr)
>> +{
>> +  elfcpp::Elf_Word omm, mm, flags = ehdr.get_e_flags();
>> +  elfcpp::Elf_Half machine = ehdr.get_e_machine();
>> +
>> +  switch (machine)
>> +    {
>> +    case elfcpp::EM_SPARC32PLUS:
>> +      this->elf_machine_ = elfcpp::EM_SPARC32PLUS;
>> +      break;
>> +
>> +    case elfcpp::EM_SPARC:
>> +    case elfcpp::EM_SPARCV9:
>> +      break;
>> +
>> +    default:
>> +      break;
>> +    }
>> +
>> +  if (!this->elf_flags_set_)
>> +    {
>> +      this->elf_flags_ = flags;
>> +      this->elf_flags_set_ = true;
>> +    }
>> +  else
>> +    {
>> +      // Accumulate cpu feature bits.
>> +      this->elf_flags_ |= (flags & (elfcpp::EF_SPARC_32PLUS
>> +                                 | elfcpp::EF_SPARC_SUN_US1
>> +                                 | elfcpp::EF_SPARC_HAL_R1
>> +                                 | elfcpp::EF_SPARC_SUN_US3));
>> +
>> +      // Bump the memory model setting to the most restrictive
>> +      // one we encounter.
>> +      omm = (this->elf_flags_ & elfcpp::EF_SPARCV9_MM);
>> +      mm = (flags & elfcpp::EF_SPARCV9_MM);
>> +      if (omm != mm)
>> +     {
>> +       if (mm == elfcpp::EF_SPARCV9_TSO)
>> +         {
>> +           this->elf_flags_ &= ~elfcpp::EF_SPARCV9_MM;
>> +           this->elf_flags_ |= elfcpp::EF_SPARCV9_TSO;
>> +         }
>> +       else if (mm == elfcpp::EF_SPARCV9_PSO
>> +                && omm == elfcpp::EF_SPARCV9_RMO)
>> +         {
>> +           this->elf_flags_ &= ~elfcpp::EF_SPARCV9_MM;
>> +           this->elf_flags_ |= elfcpp::EF_SPARCV9_PSO;
>> +         }
>> +     }
>> +    }
>> +
>> +  // Validate that the little-endian flag matches how we've
>> +  // been instantiated.
>> +  if (!(flags & elfcpp::EF_SPARC_LEDATA) != big_endian)
>> +    {
>> +      if (big_endian)
>> +     gold_error(_("%s: Little endian elf flag set on BE object"),
>> +                  name.c_str());
>> +      else
>> +     gold_error(_("%s: Little endian elf flag clear on LE object"),
>> +                  name.c_str());
>> +    }
>> +
>> +  return Target::do_make_elf_object(name, input_file, offset, ehdr);
>> +}
>> +
>> +// Adjust ELF file header.
>> +
>> +template<int size, bool big_endian>
>> +void
>> +Target_sparc<size, big_endian>::do_adjust_elf_header(
>> +    unsigned char* view,
>> +    int len) const
>> +{
>> +  elfcpp::Ehdr_write<size, big_endian> oehdr(view);
>> +
>> +  oehdr.put_e_machine(this->elf_machine_);
>> +  oehdr.put_e_flags(this->elf_flags_);
>> +
>> +  Sized_target<size, big_endian>::do_adjust_elf_header(view, len);
>> +}
>> +
>>  // The selector for sparc object files.
>>
>>  template<int size, bool big_endian>
>> --
>> 1.7.9.5
>>