Re: [RFA] DWARF multiple comp unit header support - Revision - Part 1

[Jim Blandy <jimb at redhat dot com>]

This looks good.  Some comments:

Petr Sorfa <petrs@caldera.com> writes:
> 2002-07-12 Petr Sorfa (petrs@caldera.com)
> 
>         *  dwarf2read.c (ABBREV_HASH_SIZE): moved definition
>            forward in the code to be defined before
>            struct comp_unit_head.
>            (comp_unit_head): Added several new members,
>            some are being used with this patch, some not.
>            offset - Offset of the cu_header in .debug_info
>            begin_offset - Base offset of cu_header into program
>            next - Next comp unit head in program
>            dwarf2_abbrevs - abbreviation tables associated with
>            comp unit header.

The members must be documented in the code, and thus need only be
named in the ChangeLog entry.

> *************** struct comp_unit_head
> *** 174,179 ****
> --- 179,194 ----
>       unsigned int offset_size;	/* size of file offsets; either 4 or 8 */
>       unsigned int initial_length_size; /* size of the length field; either
>                                            4 or 12 */
> + 
> +     /* New information for the comp unit head so as to keep a list
> +        of available ones for a program. */
> +     unsigned int offset; /* Offset of the cu_header in .debug_info */
> +     char *base_offset; /* Base offset after cu_header into program */
> +     char *begin_offset; /* Base offset of cu_header into program */
> +     struct comp_unit_head *next; /* Next comp unit head in program */
> + 
> +     struct abbrev_info *dwarf2_abbrevs[ABBREV_HASH_SIZE]; /* DWARF abbrev
> +                                                              table */
>     };
>   
>   /* The line number information for a compilation unit (found in the

These comments need to be much more expansive.  It's very important
that data structures be clearly explained.  How is "Base offset
*after* cu_header into program" different from "Base offset *of*
cu_header into program"?

Have you compared test suite results with and without this patch?