I've committed this patch.
-cary
2013-06-10 Cary Coutant <ccout...@google.com>
gcc/
* dwarf2out.c (hash_external_ref): Use die_symbol or signature
for hash so that hash table traversal order is deterministic.
> Index: gcc/dwarf2out.c
> ===================================================================
> --- gcc/dwarf2out.c (revision 198260)
> +++ gcc/dwarf2out.c (working copy)
> @@ -7385,7 +7385,22 @@ static hashval_t
> hash_external_ref (const void *p)
> {
> const struct external_ref *r = (const struct external_ref *)p;
> - return htab_hash_pointer (r->type);
> + dw_die_ref die = r->type;
> + hashval_t h = 0;
> +
> + /* We can't use the address of the DIE for hashing, because
> + that will make the order of the stub DIEs non-deterministic. */
> + if (! die->comdat_type_p)
> + /* We have a symbol; use it to compute a hash. */
> + h = htab_hash_string (die->die_id.die_symbol);
> + else
> + {
> + /* We have a type signature; use a subset of the bits as the hash.
> + The 8-byte signature is at least as large as hashval_t. */
> + comdat_type_node_ref type_node = die->die_id.die_type_node;
> + memcpy (&h, type_node->signature, sizeof (h));
> + }
> + return h;
> }
>
> /* Compare external_refs. */
