[Bug c++/99174] New: [modules] ICE with recursive inclusion of header-unit

[Bug c++/99174] New: [modules] ICE with recursive inclusion of header-unit

[nathan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99174

            Bug ID: 99174
           Summary: [modules] ICE with recursive inclusion of header-unit
           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: ---

self-inclusion considered dangerous

// 1_b.ii
import "./1_b.ii";



./cc1plus -quiet -std=c++20 -fmodule-header 1_b.ii                              
1_b.ii:1:1: internal compiler error: in read_preprocessor, at
cp/module.cc:17891
    1 | import "./1_b.ii";
      | ^~~~~~
0xce6da8 module_state::read_preprocessor(bool)
        ../../../src/gcc/cp/module.cc:17891
0xceb5db preprocess_module(module_state*, unsigned int, bool, bool, bool,
cpp_reader*)
        ../../../src/gcc/cp/module.cc:19446
0xc73707 module_token_filter::resume(int, int, tree_node*, unsigned int)
        ../../../src/gcc/cp/lex.c:520
0xc71c69 module_token_lang(int, int, tree_node*, unsigned int, unsigned long)
        ../../../src/gcc/cp/lex.c:557
0xd26638 cp_lexer_new_main
        ../../../src/gcc/cp/parser.c:658
0xd90362 c_parse_file()
        ../../../src/gcc/cp/parser.c:45168
0xf5194e c_common_parse_file()
        ../../../src/gcc/c-family/c-opts.c:1218

[Bug c++/99174] [modules] ICE with recursive inclusion of header-unit

[nathan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99174

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |nathan at gcc dot gnu.org
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2021-02-22
     Ever confirmed|0                           |1

[Bug c++/99174] [modules] ICE with recursive inclusion of header-unit

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99174

--- 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:afed55036b65526be006d55f003f670ebeadb223

commit r11-7324-gafed55036b65526be006d55f003f670ebeadb223
Author: Nathan Sidwell <nathan@acm.org>
Date:   Mon Feb 22 07:43:56 2021 -0800

    c++: Recursing header imports and other duplicates [PR 99174]

    The fix for 98741 introduced two issues.  (a) recursive header units
    iced because we tried to read the preprocessor state after having
    failed to read the config.  (b) we could have duplicate imports of
    named modules in our pending queue, and that would lead to duplicate
    requests for pathnames, which coupled with the use of a null-pathname
    to indicate we'd asked could lead to desynchronization with the module
    mapper.  Fixed by adding a 'visited' flag to module state, so we ask
    exactly once.

            PR c++/99174
            gcc/cp
            * module.cc (struct module_state): Add visited_p flag.
            (name_pending_imports): Use it to avoid duplicate requests.
            (preprocess_module): Don't read preprocessor state if we failed to
            load a module's config.
            gcc/testsuite/
            * g++.dg/modules/pr99174-1_a.C: New.
            * g++.dg/modules/pr99174-1_b.C: New.
            * g++.dg/modules/pr99174-1_c.C: New.
            * g++.dg/modules/pr99174.H: New.

[Bug c++/99174] [modules] ICE with recursive inclusion of header-unit

[nathan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99174

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

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

--- Comment #2 from Nathan Sidwell <nathan at gcc dot gnu.org> ---
afed55036b6 2021-02-22 | c++: Recursing header imports and other duplicates [PR
99174]