Adding MIPS support to GOLD

[David Daney]

Rick Mann wrote:
> 
> On Mar 25, 2008, at 10:22 AM, David Daney wrote:
>> I was thinking about looking at MIPS support, however I think it may 
>> be a bit complicated.  The Multi-GOT support is something that does 
>> not exist for x86, so it would be completely new.  The rest (having 
>> not looked at the gold source code yet), I think would be mostly 
>> straight forward.
> 
> 
> I consider myself a fairly expert programmer, but not in the area of 
> language tools, and sadly it gets harder for me when looking at 
> something like GCC and binutils (I'm really a Mac programmer, using the 
> traditional Mac APIs). Is there someplace I can learn about the GOT, why 
> multi-GOT exists for MIPS and not for x86, how it's used, etc.?
> 

It is a consequence of immediate data being limited to 16 bits in MIPS 
ISAs.  You can only efficiently access 2^14 GOT/PLT entries.  To work 
around this problem, ld generates multiple GOTs if required.


> (If you give me a specific task in binutils, I can probably help. If you 
> tell me to design something, I need to learn more about the problem 
> domain.)

That is a truism.  You would probably need to familiarize yourself with 
the ELF, and the mips psABI specifications for unix/linux

David Daney