Re: [GOLD][PATCH] Set SHF_LINK_ORDER flags of ARM EXIDX sections.

[=?big5?b?RG91ZyBLd2FuICjD9q62vHcp?= <dougkwan at google dot com>]

Gold does not handle SHF_LINK_ORDER flag in general, we drop the flag
when searching for an output section.

Output_section*
Layout::choose_output_section(const Relobj* relobj, const char* name,
                              elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
                              bool is_input_section, Output_section_order order,
                              bool is_relro)
...

  // Some flags in the input section should not be automatically
  // copied to the output section.
  flags &= ~ (elfcpp::SHF_INFO_LINK
              | elfcpp::SHF_LINK_ORDER
              | elfcpp::SHF_GROUP
              | elfcpp::SHF_MERGE


在 2010年10月19日下午10:07，Ian Lance Taylor <iant@google.com> 寫道：
> "Doug Kwan (關振德)" <dougkwan@google.com> writes:
>
>>     This patch changes code writing output section headers so that the
>> SHF_LINK_ORDER flag of a section of type SHT_ARM_EXIDX is always set.
>> The flag is required to be set for such a section by the ARM EHABI.
>> The existing code drops the SHF_LINK_ORDER flag and that confuses
>> other tools.  Gold does not handle SHF_LINK_ORDER in general but the
>> ARM back-end can handle the EXIDX sections.
>>
>> -Doug
>>
>>
>> 2010-10-19  Doug Kwan  <dougkwan@google.com>
>>
>>         * output.cc(Output_section::write_header): Set SHF_LINK_ORDER flags of
>>         ARM EXIDX sections.
>
> I don't see the ARM backend actually creating any SHT_ARM_EXIDX
> sections.  So it seems to me that they are input sections.  If the ABI
> requires the input sections to have the SHF_LINK_ORDER flag set, then
> that setting should carry through to the output section.  Does that not
> happen?
>
> Ian
>