Re: [RFC] Passing MIPS debug hints between gcc and gdb

Richard Sandiford
2006-05-18T10:09:17Z

Mark Mitchell <mark@codesourcery.com> writes:
> Fred Fish wrote:
>> On Thursday 11 May 2006 02:57, Richard Sandiford wrote:
>>> Using empty sections was always a hack, to be honest (modelled on the
>>> old .gcc_compiled_v3 thing, whatever it was called). I suppose we
>>> should be using note sections really.
>>
>> Wouldn't that be ELF specific, [...]

Yes, but that isn't a problem. MIPS gcc only supports ELF targets
these days.

>> [...] as well as requiring the linker to
>> merge hint strings? I'm a little unclear on just what capabilities
>> the current linker has to merge section contents so that "hint
>> strings" put into a note section wouldn't be duplicated in the final
>> linked output, one for each compilation unit.
>
> The ARM EABI contains a specification for object-file attributes,
> including rules about how to merge them. The specification is quite
> general; there are mechanisms for compiler extension, etc.
>
> It is indeed ELF-specific, but I would guess you could use the same
> technique on other object formats that allow additional sections.
>
> I'm not sure what the current state of support for this feature is in
> Binutils, but I think we should consider using the ARM strategy on all
> platforms without a previously defined mechanism of their own; we want
> it anyhow (for ARM), and we can presumably avoid duplicate effort/code
> by reusing the code.

I haven't looked at the ARM EABI in detail, but FWIW, that principle
sounds good to me too. I agree that it's better to avoid reinventing
the wheel.

Richard