[PATCH v2] Add a trie to map quickly from address range to compilation unit.

[Alan Modra]

On Fri, Apr 08, 2022 at 12:43:14PM +0200, Jan Beulich wrote:
> On 08.04.2022 12:38, Alan Modra wrote:
> > On Fri, Apr 08, 2022 at 10:05:55AM +0200, Jan Beulich via Binutils wrote:
> >> On 04.04.2022 09:32, Steinar H. Gunderson via Binutils wrote:
> >>> +  if (leaf != NULL)
> >>> +    leaf->head.num_room_in_leaf = TRIE_LEAF_SIZE;
> >>> +  return (struct trie_node *) leaf;
> >>
> >> Furthermore, with casts being somewhat risky in general (and there not
> >> being more fine-grained C++-like casts in C), I think it would be better
> >> to use &leaf->head in such cases.
> > 
> > Except that if leaf can be NULL then &leaf->head is undefined
> > according to the C standard.  ubsan will complain.  I dislike casts
> > too, but this is one annoying case where C requires one.
> 
>   if (leaf == NULL)
>     return NULL;
>   leaf->head.num_room_in_leaf = TRIE_LEAF_SIZE;
>   return &leaf->head;

Yes, that's fine.

  return leaf ? &leaf->head : NULL;

works too but I find it a little awkward.

BTW, a cast to the proper type is no better really than
  return (void *) leaf;
Minimal typing and makes C++ heads explode.  :-)

I'm not trying to lay down style rules here.  Anything that avoids
ubsan errors is OK as far as I'm concerned.

-- 
Alan Modra
Australia Development Lab, IBM