[Bug c++/100673] New: [coroutines] Non-template, UDT await_suspend return-type results in ICE.

[Bug c++/100673] New: [coroutines] Non-template, UDT await_suspend return-type results in ICE.

[jehelset at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100673

            Bug ID: 100673
           Summary: [coroutines] Non-template, UDT await_suspend
                    return-type results in ICE.
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jehelset at gmail dot com
  Target Milestone: ---

Created attachment 50844
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50844&action=edit
ICE on non-template UDT  await_suspend return-type.

A non-template udt return-type from await_suspend will ICE on trunk:

https://godbolt.org/z/Gn7djfrac

#0  build_co_await (loc=674010823, a=0x7ffff163f1c0, suspend_kind=<optimized
out>) at ../../gcc/cp/coroutines.cc:993
993           tree tt = CLASSTYPE_TI_TEMPLATE (susp_return_type);

Relevant code:
  else if (TREE_CODE (susp_return_type) == RECORD_TYPE
           && CLASS_TYPE_P (susp_return_type))
    {
      tree tt = CLASSTYPE_TI_TEMPLATE (susp_return_type);
      if (tt == coro_handle_templ)
        ok = true;
    }

Seems to be checking the validity of the await_suspend call, to produce a
helpful diagnostic. Perhaps the conditional also needs to verify that
CLASSTYPE_TEMPLATE_INFO (coro_handle_templ) is non-NULL, before using
CLASSTYPE_TI_TEMPLATE.

Seemed to be the case on 10.3, 11.1 and on 12.0. 10.2 failed to compile it
without crashing.

[Bug c++/100673] [coroutines] Non-template, UDT await_suspend return-type results in ICE.

[jehelset at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100673

--- Comment #1 from John Eivind Helset <jehelset at gmail dot com> ---
Created attachment 50854
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50854&action=edit
Add CLASSTYPE_TEMPLATE_INFO guard and test-case.

Tried to guard the the conditional with CLASSTYPE_TEMPLATE_INFO as it seemed
like the common approach in the codebase, to verify that the return-type was a
template. And a testcase.

Remove the guard to observe ICE in the test-case.

[Bug c++/100673] [coroutines] Non-template, UDT await_suspend return-type results in ICE.

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100673

Iain Sandoe <iains at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2021-10-1
                 CC|                            |iains at gcc dot gnu.org

--- Comment #2 from Iain Sandoe <iains at gcc dot gnu.org> ---
thanks for the patch - queued to apply.

[Bug c++/100673] [coroutines] Non-template, UDT await_suspend return-type results in ICE.

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100673

Iain Sandoe <iains at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

[Bug c++/100673] [coroutines] Non-template, UDT await_suspend return-type results in ICE.

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100673

Iain Sandoe <iains at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |iains at gcc dot gnu.org

[Bug c++/100673] [coroutines] Non-template, UDT await_suspend return-type results in ICE.

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100673

--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Iain D Sandoe <iains@gcc.gnu.org>:

https://gcc.gnu.org/g:8009c79b64b532d8a0966fe3c6d636369df6e35d

commit r12-4101-g8009c79b64b532d8a0966fe3c6d636369df6e35d
Author: John Eivind Helset <jehelset@gmail.com>
Date:   Sat May 22 01:53:22 2021 +0200

    coroutines: Fix ICE with an invalid await_suspend type [PR100673].

    The reported ICE occurs when an invalid (non-template) type is found
    as the return for an await_suspend.

    Fixed by amending build_co_await to ensure that await_suspend return-
    type is a template-instantiation before checking to see if it is a
    valid coroutine handle type.

    Signed-off-by: John Eivind Helset <jehelset@gmail.com>
    Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>

            PR c++/100673

    gcc/cp/ChangeLog:

            * coroutines.cc (build_co_await): Guard against NULL
            await_suspend types.

    gcc/testsuite/ChangeLog:

            * g++.dg/coroutines/pr100673.C: New test.

[Bug c++/100673] [coroutines] Non-template, UDT await_suspend return-type results in ICE.

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100673

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jack.cui2 at foxmail dot com

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 103790 has been marked as a duplicate of this bug. ***

[Bug c++/100673] [coroutines] Non-template, UDT await_suspend return-type results in ICE.

[jehelset at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100673

John Eivind Helset <jehelset at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #5 from John Eivind Helset <jehelset at gmail dot com> ---
Looks good now!