Hello Jakub, hi Honza,

On 8/31/20 5:53 PM, Jakub Jelinek wrote:
> On Mon, Aug 03, 2020 at 05:37:40PM +0200, Tobias Burnus wrote:
>> It turned out that the omp_discover_declare_target_tgt_fn_r
>> discovered all nodes – but as it tagged the C++ alias nodes
>> and not the streamed-out nodes, no device function was created
...
>>         if (node != NULL)
>>      {
>> +      if (node->cpp_implicit_alias)
>> +        {
>> +          node = node->get_alias_target ();
>> +          if (!omp_declare_target_fn_p (node->decl))
>> +            ((vec<tree> *) data)->safe_push (node->decl);
>> +          DECL_ATTRIBUTES (node->decl)
>> +            = tree_cons (id, NULL_TREE, DECL_ATTRIBUTES (node->decl));
>> +        }
>>        node->offloadable = 1;
> I don't see what is special on cpp_implicit_alias here, compared to any
> other aliases.
> So, I wonder if the code shouldn't do:
> ...

Granted that cpp_implicit_alias is not special; however,
for the alias attribute, the name is different and, thus,
the decl is in a different sym node.

Updated version attached. Does it seem to make sense?

Tobias


>        tree decl = *tp;
>        symtab_node *node = symtab_node::get (decl);
>        if (node != NULL)
>       {
>         symtab_node *anode = node->ultimate_alias_target ();
>         if (anode && anode != node)
>           {
>             decl = anode->decl;
>             gcc_assert (TREE_CODE (decl) == FUNCTION_DECL);
>             if (omp_declare_target_fn_p (*tp)
>                 || lookup_attribute ("omp declare target host",
>                                      DECL_ATTRIBUTES (decl)))
>               return NULL_TREE;
>             node = anode;
>           }
>       }
>        tree id = get_identifier ("omp declare target");
>        if (!DECL_EXTERNAL (decl) && DECL_SAVED_TREE (decl))
>          ((vec<tree> *) data)->safe_push (decl);
>        DECL_ATTRIBUTES (decl) = tree_cons (id, NULL_TREE, DECL_ATTRIBUTES (decl));
>        if (node != NULL)
>          {
>            node->offloadable = 1;
>            if (ENABLE_OFFLOADING)
>              g->have_offload = true;
>          }
>
> Otherwise, if we have say:
> void foo () { }
> void bar () __attribute__((alias ("foo")));
> void baz () __attribute__((alias ("bar")));
> int
> main ()
> {
>    #pragma omp target
>    baz ();
> }
> we won't mark foo as being declare target.
> Though, maybe that is not enough and we need to mark all the aliases from
> node to the ultimate alias that way (so perhaps instead iterate one
> get_alias_target (if node->alias) by one and mark all the decls the way the
> code marks right now (i.e. pushes those non-DECL_EXTERNAL with
> DECL_SAVED_TREE for further processing and add attributes to all of them?
>
>       Jakub
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