Re: sections, overview of their meaning?

[Torsten Mohr <tmohr at s dot netic dot de>]

Hi Nick,

thanks a lot for your help, i really appreciate that.

I first tried to ask for an overview of sections because i
don't want to flood the group with questions about every section.
I want to make sure that every section in an own linker script
goes where it should go (ROM, RAM , ignored, ...).

Basically, i'd like to ask for nearly all sections in the
original V850 linker script, except the obvious ones like
.text, .data, .bss, ... .  What is ".dynamic" doing, what
are all the .rel* and .rela* for?
What about .ctors and .dtors?  They sound like C++ constructors
and destructors, but do they contain code (ROM) or data (RAM)
used in the constructors?


Would it make sense to set up an ordered list of the
sections with a description and a comment what platform(s)
it is used in?


Best regards,
Torsten.


> Hi Torsten,
>
> > there are lots of different sections in linker scripts, i know
> > some of them but there are quite many that i don't know.
> >
> > Is there somewhere an overview on the sections and what is meant
> > to go into them?
>
> Sorry no.  Sections can have arbitrary names and arbitrary contents, and
> there is no one single place where these names and contents are specified.
>
> Some section names are commonly known and have a reasonably well defined
> purpose.  You probably know these names already.  eg: .text for code,
> .data for initialised, modifiable data, .bss for zero-initialised or
> uninitialised data, .rdata for non-modifiable data.
>
> Other sections are often documented in the EABI for each particular
> processor.  So for example the ARM EABI describes sections called
> .ARM.exidx and .ARM.attributes.  (I tried to find a V850 based example,
> but I cannot find the ABI for this processor).
>
> Otherwise the best guess is the name of the section itself.  Sometimes
> there will be comments in the linker script explaining what the section
> is for, but this is not always done.  For example the .zdata data
> section used by the V850 linker scripts is there for data that is
> accessed relative to r0 register, as hinted at by the "z" in the name,
> and the .rosdata section is for read-only data that is accessed via the
> global pointer register (r4), as hinted at by the definition of the __gp
> symbol in the .sdata section.
>
> For sections that still mystify you please feel free to ask on this
> list, or search for references to them in the code for gas and gcc.
>
> Cheers
>    Nick