Re: Mixing 32-bit and 64-bit DWARF2/3 sections

[Daniel Jacobowitz <drow@false.org>]

On Sun, Nov 07, 2004 at 05:28:41PM +0100, Mark Kettenis wrote:
>    Date: Sun, 7 Nov 2004 10:31:44 -0500
>    From: Daniel Jacobowitz <drow@false.org>
> 
>    On Sun, Nov 07, 2004 at 03:28:07PM +0100, Mark Kettenis wrote:
>    > Currently GDB barfs when you use it on an executable that contains
>    > compilation units that mix 32-bit and 64-bit DWARF sections.  Looking
>    > at the (latest?) DWARF3 draft it doesn't seem to be unreasonable that
>    > it does so:
>    > 
>    >   "The 32-bit and 64-bit DWARF format conventions must not be
>    >    intermixed within a single compilation unit."
> 
>    I'd read that as saying that GDB should support what you describe. 
>    This isn't mixing them within a single compilation unit.  What falls
>    down?
> 
> No I'm really talking about mixing 32-bit and 64-bit DWARF format
> within the same compilation unit.  In the case of OpenBSD/mips64 GCC
> generates a 32-bit .debug_info section and .file directives that
> contain the line info.  These .file directives are then converted by
> gas into 64-bit .debug_line sections.
> 
> When GDB reads these it dumps core.  I'm working on patches to fix
> this, but I'm not yet completely satisfied with them.

Ah!  I understand now, thanks.

I think GDB should complain noisily about this.  One nice fix to this
in gas would be for it to detect the format of .debug_info and match it
when generating .debug_line.  Another would be to add command line
options for 32-bit and 64-bit .debug_line and make GCC instruct it on
which to use - that's a bit more complicated to implement.

-- 
Daniel Jacobowitz