Re: [RFA] Artifical dwarf2 debug info

[Daniel Jacobowitz <drow@mvista.com>]

On Mon, Dec 16, 2002 at 02:58:18PM +0100, Michal Ludvig wrote:
> Daniel Jacobowitz wrote:
> >On Sun, Dec 15, 2002 at 01:48:12AM +0100, Michal Ludvig wrote:
> >
> >>this long patch provides a fix for a very annoying fact, that GDB on 
> >>x86-64 can't do backtraces from hand-optimized assembler functions (that 
> >>applies for example to glibc's memset, str*, etc as well as to syscall 
> >>wrappers).
> >
> >Workaround, really - just for some particular functions...
> 
> Yes, but still better than nothing ;-)

Yeah.

> OK, the attached patch has a modified gdbarch.sh and regenerated 
> gdbarch.[ch].
> 
> I've also put a description into gdbint.texinfo

OK, Eli will have to approve that part.

> >>OK to commit to branch and mainline?
> >
> >I do not believe this is appropriate for the branch, at least until
> >it's sat on mainline without causing problems for some time.
> 
> It shouldn't cause any problems because all the machinery is invoked if 
> and only if the target allowed it, and then if a FDE isn't found for a 
> particular function. Typically only two or three times on x86-64 and 
> zero times on other archs.
> 
> Can I put it at least to mainline?

A little way to go yet.  Please don't just export things from
dwarf2cfi:

> +/* Common Information Entry - holds information that is shared among many
> +   Frame Descriptors.  */
> +struct cie_unit

This is fine for now.

> +/* Frame Description Entry.  */
> +struct fde_unit
> +{

So's this.

> +struct fde_array
> +{
> +  struct fde_unit **array;
> +  int elems;
> +  int array_size;
> +};
> +
> +extern struct cie_unit *cie_chunks;
> +extern struct fde_array fde_chunks;
> +

But these aren't.  Add a function to link a new FDE or CIE, please.

> +struct cie_unit *cie_unit_alloc (void);
> +struct fde_unit *fde_unit_alloc (void);

These make sense...

> +void fde_chunks_need_space (void);
> +int compare_fde_unit (const void *a, const void *b);

But these aren't necessary if you add said function.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer