Re: [gold] PowerPC PLT

[Ian Lance Taylor <iant at google dot com>]

"David Edelsohn" <dje.gcc@gmail.com> writes:

> On Tue, Nov 18, 2008 at 10:49 AM, Ian Lance Taylor <iant@google.com> wrote:
>
>>> +       // Define blrl instruction at _G_O_T_ - 4 for old ABI.
>>> +       this->got_->add_constant(blrl);
>>>         // Define _GLOBAL_OFFSET_TABLE_ at the start of the .got section.
>>> +       Symbol *got_anchor =
>>>         symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
>>> !                                 this->got_plt_,
>>>                                   0, 0, elfcpp::STT_OBJECT,
>>>                                   elfcpp::STB_LOCAL,
>>>                                   elfcpp::STV_HIDDEN, 0,
>>>                                   false, false);
>>> +       // ???
>>> +       got_anchor->set_got_offset (GOT_TYPE_STANDARD, 1);
>>
>> Calling set_got_offset here may be correct but it seems odd.  Normally
>> the linker calls set_got_offset for a symbol which is referenced by a
>> relocation type which requires a GOT entry.  _GLOBAL_OFFSET_TABLE_
>> points to the GOT but it does not itself have a GOT entry.
>
> Thanks for the explanations and feedback.  My intent was to set the
> beginning of the GOT at _G_O_T_, allowing for the blrl instruction
> immediately before it.  I think it is better and simpler not to try to support
> the old PPC32 ABI in gold.

Defining _GLOBAL_OFFSET_TABLE_ is sensible and appropriate.  Calling
set_got_offset on that symbol seems unnecessary.

Ian