Re: [Libunwind-devel] Interest in .debug_frame support?

[Daniel Jacobowitz]

Hi Arun,

On Wed, Oct 03, 2007 at 08:20:08AM -0700, Arun Sharma wrote:
>  This is a
> > debugging feature, so I'm willing to put extra data on the target
> > during it, probably using .gnu_debuglink to point at separate files.
> > But the overhead of .eh_frame is not acceptable.
> 
> 
> Can you describe what are the overheads you're worried about? Just the
> binary size?

Many of our customers are embedded systems developers.  Although the
thresholds have changed as everything gets smaller, faster, cheaper,
and better, file size and memory usage are both major concerns.  I
don't want to rely on .eh_frame because we can't strip allocated
sections in the deployment process; we'd have to rebuild without
them, with everything that implies about validation.

.gnu_debuglink, on the other hand, is easy.  It's not allocated so
we can strip it if we want to.  And it's a small fixed size per
library rather than proportional to code size, so in most cases we
can leave it in.  Removing files that are only used during debugging
is easy too.

(Also, I'm trying to do this particular project for a toolchain that's
been in the field for a while; telling people to rebuild everything
they want to trace and turn on .eh_frame generation is not going to
get me very far.)

-- 
Daniel Jacobowitz
CodeSourcery