Re: [PATCH 3/6] Pass section index to start_compunit_symtab

[Simon Marchi <simark@simark.ca>]

>  /* Subroutine of augment_type_symtab to simplify it.
> diff --git a/gdb/buildsym.h b/gdb/buildsym.h
> index 9724607f3d9..0464c738114 100644
> --- a/gdb/buildsym.h
> +++ b/gdb/buildsym.h
> @@ -146,18 +146,23 @@ struct buildsym_compunit
>       (or NULL if not known).
>  
>       NAME and NAME_FOR_ID have the same purpose as for the start_subfile
> -     method.  */
> +     method.
> +
> +     SECTION_INDEX is the index of the section for the compunit and
> +     for block symbols in this compunit.  Normally SECT_OFF_TEXT.  */

I don't understand this comment, specifically how a compunit can "have"
a single section.  Don't compunits define data and text symbols, which
have different sections, for instance?

From what I can see, this section index is ultimately use to apply /
unapply a relocation offset when dealing with call sites (e.g.
compunit_symtab::find_call_site), so it makes sense that we want the
text section (call site addresses are code addresses).  So maybe the
comment and / or the field name could reflect that this is the section
index for the code / text section.  Just saying "section index" doesn't
tell much about which section it is.

I'm curious to know why we have to store that and we can't always use
SECT_OFF_TEXT, but I guess that will come with the following patches.

Simon