[Bug middle-end/96390] [OpenMP] Link errors on the offload side for C++ code with templates

[burnus at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96390

Tobias Burnus  changed:

   What|Removed |Added

 Status|UNCONFIRMED |RESOLVED
 Resolution|--- |FIXED

--- Comment #5 from Tobias Burnus  ---
FIXED on GCC 11 (= mainline).

[Bug middle-end/96390] [OpenMP] Link errors on the offload side for C++ code with templates

[cvs-commit at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96390

--- Comment #4 from CVS Commits  ---
The master branch has been updated by Tobias Burnus :

https://gcc.gnu.org/g:2a10a2c0689db280ee3a94164504b7196b8370f4

commit r11-3505-g2a10a2c0689db280ee3a94164504b7196b8370f4
Author: Tobias Burnus 
Date:   Mon Sep 28 18:08:05 2020 +0200

OpenMP: Handle cpp_implicit_alias in declare-target discovery (PR96390)

gcc/ChangeLog:

PR middle-end/96390
* omp-offload.c (omp_discover_declare_target_tgt_fn_r): Handle
alias nodes.

libgomp/ChangeLog:

PR middle-end/96390
* testsuite/libgomp.c++/pr96390.C: New test.
* testsuite/libgomp.c-c++-common/pr96390.c: New test.

[Bug middle-end/96390] [OpenMP] Link errors on the offload side for C++ code with templates

[burnus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96390

--- Comment #3 from Tobias Burnus  ---
The following helps with the "S<0>::S()" problem – but then one runs into the
"V<1>::V" problem.

--- a/gcc/omp-offload.c
+++ b/gcc/omp-offload.c
@@ -207,6 +207,12 @@ omp_discover_declare_target_tgt_fn_r (tree *tp, int 
   symtab_node *node = symtab_node::get (*tp);
   if (node != NULL)
{
+ if (node->cpp_implicit_alias)
+   {
+ node = node->get_alias_target ();
+ DECL_ATTRIBUTES (node->decl)
+   = tree_cons (id, NULL_TREE, DECL_ATTRIBUTES (node->decl));
+   }
  node->offloadable = 1;
  if (ENABLE_OFFLOADING)
g->have_offload = true;

[Bug middle-end/96390] [OpenMP] Link errors on the offload side for C++ code with templates

[burnus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96390

--- Comment #2 from Tobias Burnus  ---
omp-offload.c's omp_discover_declare_target_tgt_fn_r sees the

::S()"

It does not call
 ((vec *) data)->safe_push (*tp);
to add it to the work list. (→ follow up issue for "V"?)

However, it sets the attribute (+ updates the node); in
omp_discover_declare_target_tgt_fn_r:

(gdb) p *tp
$27 = (tree) 0x77648e00
(gdb) p debug_tree((*tp)->decl_common.attributes)
 >>

But later in dump_function_to_file:

(gdb) p fndecl
$30 = (tree) 0x77648f00
(gdb) p debug_tree(fndecl->decl_common.attributes)

$31 = void

Thus, there is now a different tree – with DECL_ATTRIBUTES stripped.

[Bug middle-end/96390] [OpenMP] Link errors on the offload side for C++ code with templates

[burnus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96390

--- Comment #1 from Tobias Burnus  ---
Created attachment 48961
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48961=edit
Test case from https://bugs.llvm.org/show_bug.cgi?id=43771 (basis for sollve_vv
test case, by Jonas Hahnfeld)