gold linker: Access section start & end address w/o using a linker script

[Ian Lance Taylor]

On Sat, Feb 1, 2014 at 5:14 PM, Kevin <ancafe@ymail.com> wrote:
> Ian Lance Taylor <iant <at> google.com> writes:
>
>>
>> On Mon, Apr 22, 2013 at 4:39 AM, Raphael Zulliger
>  <zulli73 <at> gmail.com> wrote:
>> >
>> > Is there a chance to enhance gold to better support such use cases?
> Or is that out-of focus for gold? I'm not
>> familiar with linking internals, but I think that providing additional
> start/end address symbols for> section names starting with a '.' wouldn't
>  be that tricky to be added, right?
>>
>> I'm fine with it.  Look for uses of is_cident in the gold source code.
>>
>> Ian
>>
>>
>
>
> Thanks for the tip Ian.  In that routine one could easily ignore a
> leading ".".  In abstract one might want to handle "." inside the
> name, or translate characters (such as "$") allowed in ELF symbols but
> not in C (or in some other language), whereby a simple concept starts
> to get out of hand; thus:
>
> - Could we assume that standard ELF section names can be mapped to C
> identifiers just by mapping the leading "."?
>
> - What mapping would you suggest?  If the leading "." is dropped then
> the resulting would collide with a common name (text or data in
> particular).  This problem seems unsolvable in general, so should one
> make an effort at all (mapping "." to a single underscore for
> example)?

The linker doesn't define symbols that are the section names: it adds
"__start_" and "__stop_" before them.  I think it would be fine to
just turn a leading '.' into a '_' for this purpose.

Ian