Re: gdb can't handle a DIE with both sibling and children

Daniel Jacobowitz
2003-07-31T18:20:58Z

On Thu, Jul 31, 2003 at 11:13:55AM -0700, H. J. Lu wrote:
> It is entirely possible for a DIE with both sibling and children. But
> scan_partial_symbols () has
>
> /* If the die has a sibling, skip to the sibling. Do not skip
> enumeration types, we want to record their enumerators. Do
> not skip namespaces, we want to record symbols inside
> them. */
> if (pdi.sibling
> && pdi.tag != DW_TAG_enumeration_type
> && pdi.tag != DW_TAG_namespace)
> {
> info_ptr = pdi.sibling;
> }
> else if (pdi.has_children)
> {
> /* Die has children, but either the optional DW_AT_sibling
> attribute is missing or we want to look at them. */
> nesting_level++;
> }
>
> That is we can't handle a DIE with both sibling and children. How
> should we fix that?

Why don't you be more specific? What problem is it causing, on what
input?

It seems quite clear that the code above is deliberately only visiting
children of DW_TAG_enumeration_type and DW_TAG_namespace, since those
are the only things whose children it needs to visit. I don't know why
it was written that way, which does seem strange; I imagine it does a
lot of useless recursing. Probably because once we get to a nested die
with no siblings, this little algorithm has no way of finding the
parent except for scanning through all the children. This looks like a
bug.

--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer