[Bug c++/99389] New: [modules] bad serialization of data

[Bug c++/99389] New: [modules] bad serialization of data

[nathan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99389

            Bug ID: 99389
           Summary: [modules] bad serialization of data
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: nathan at gcc dot gnu.org
  Target Milestone: ---

Triaging 99377 runs into this:

// bug_a.ii
template<typename _CharT>
class basic_string_view
{
public:
  basic_string_view(const _CharT* __str) noexcept
  {}
  bool
    empty() const noexcept
  { return !_M_len; }

private:
  unsigned _M_len;
};

using string_view = basic_string_view<char>;

// bug_b.ii
export module hello;

import "bug_a.ii";

export inline bool Check (const string_view& n)
{
  return !n.empty ();
}


// bug_c.ii
import hello;

int main ()
{
  return Check ("World") ? 0 : 1;
}

./cc1plus -quiet -fmodule-header   bug_a.ii && ./cc1plus -quiet -fmodules-ts
bug_b.ii && ./cc1plus -quiet -fmodules-ts bug_c.ii
In module imported at bug_c.ii:1:1:
hello: In function 'int main()':
hello: error: failed to read compiled module cluster 1: Bad file data
hello: note: compiled module file is 'gcm.cache/hello.gcm'
hello: error: failed to read compiled module cluster 2: Bad file data
bug_c.ii:5:10: fatal error: failed to load binding '::Check@hello'
    5 |   return Check ("World") ? 0 : 1;
      |          ^~~~~

we failed to find _M_len as that instantiation's not (yet?) loaded

[Bug c++/99389] [modules] bad serialization of data

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99389

--- Comment #1 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Nathan Sidwell <nathan@gcc.gnu.org>:

https://gcc.gnu.org/g:4d66685e49d20e0c7a87c5fa0757c7eb63ffcdaa

commit r11-7524-g4d66685e49d20e0c7a87c5fa0757c7eb63ffcdaa
Author: Nathan Sidwell <nathan@acm.org>
Date:   Fri Mar 5 05:25:54 2021 -0800

    c++: instantiating imported specializations [PR 99389]

    When an incomplete class specialization is imported, and is completed
    by instantiation, we were failing to mark the instantiation, and thus
    didn't stream it out.  Leading to errors in importing as we had
    members of an incomplete type.

            PR c++/99389
            gcc/cp/
            * pt.c (instantiate_class_template_1): Set instantiating module
            here.
            gcc/testsuite/
            * g++.dg/modules/pr99389_a.H: New.
            * g++.dg/modules/pr99389_b.C: New.
            * g++.dg/modules/pr99389_c.C: New.

[Bug c++/99389] [modules] bad serialization of data

[nathan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99389

Nathan Sidwell <nathan at gcc dot gnu.org> changed:

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

--- Comment #2 from Nathan Sidwell <nathan at gcc dot gnu.org> ---
4d66685e49d 2021-03-05 | c++: instantiating imported specializations [PR 99389]