[Bug c++/98626] New: UBSAN: vec.h:591:30: runtime error: member access within null pointer of type 'struct vec'

[Bug c++/98626] New: UBSAN: vec.h:591:30: runtime error: member access within null pointer of type 'struct vec'

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98626

            Bug ID: 98626
           Summary: UBSAN: vec.h:591:30: runtime error: member access
                    within null pointer of type 'struct vec'
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: marxin at gcc dot gnu.org
                CC: nathan at gcc dot gnu.org
            Blocks: 63426
  Target Milestone: ---

I see the following with UBSAN compiler:

$ ./xg++ -B.
/home/marxin/Programming/gcc/gcc/testsuite/g++.dg/modules/mod-decl-2_a.C -c
-fmodules-ts
...
$ ./xg++ -B.
/home/marxin/Programming/gcc/gcc/testsuite/g++.dg/modules/mod-decl-2_b.C -c
-fmodules-ts
/home/marxin/Programming/gcc/gcc/testsuite/g++.dg/modules/mod-decl-2_b.C:4:1:
error: cannot import module in its own purview
    4 | import bob; // { dg-error "cannot import module.* in its own purview" }
      | ^~~~~~
In module imported at
/home/marxin/Programming/gcc/gcc/testsuite/g++.dg/modules/mod-decl-2_b.C:4:1:
bob: note: module ‘bob’ declared here
/home/marxin/Programming/gcc2/gcc/cp/typeck.c:4024:33: runtime error: member
call on null pointer of type 'struct vec'
    #0 0x1403445 in cp_build_function_call_vec(tree_node*, vec<tree_node*,
va_gc, vl_embed>**, int, tree_node*)
/home/marxin/Programming/gcc2/gcc/cp/typeck.c:4024
    #1 0xfdd5bf in module_add_import_initializers()
/home/marxin/Programming/gcc2/gcc/cp/module.cc:18995
    #2 0xdc20f9 in start_objects
/home/marxin/Programming/gcc2/gcc/cp/decl2.c:3745
    #3 0xdc4b3b in generate_ctor_or_dtor_function
/home/marxin/Programming/gcc2/gcc/cp/decl2.c:4310
    #4 0xdccb6c in c_parse_final_cleanups()
/home/marxin/Programming/gcc2/gcc/cp/decl2.c:5234
    #5 0x15ae87f in c_common_parse_file()
/home/marxin/Programming/gcc2/gcc/c-family/c-opts.c:1233
    #6 0x2ccb435 in compile_file /home/marxin/Programming/gcc2/gcc/toplev.c:457
    #7 0x2cd3e17 in do_compile /home/marxin/Programming/gcc2/gcc/toplev.c:2193
    #8 0x2cd441a in toplev::main(int, char**)
/home/marxin/Programming/gcc2/gcc/toplev.c:2332
    #9 0x59b3bff in main /home/marxin/Programming/gcc2/gcc/main.c:39
    #10 0x7ffff6ce5151 in __libc_start_main (/lib64/libc.so.6+0x28151)
    #11 0xa82bdd in _start
(/home/marxin/Programming/gcc2/objdir/gcc/cc1plus+0xa82bdd)


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63426
[Bug 63426] [meta-bug] Issues found with -fsanitize=undefined

[Bug c++/98626] UBSAN: vec.h:591:30: runtime error: member access within null pointer of type 'struct vec'

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98626

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2021-01-11
     Ever confirmed|0                           |1

[Bug c++/98626] UBSAN: vec.h:591:30: runtime error: member access within null pointer of type 'struct vec'

[nathan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98626

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED

--- Comment #1 from Nathan Sidwell <nathan at gcc dot gnu.org> ---
magic configure: --with-build-config=bootstrap-ubsan

[Bug c++/98626] UBSAN: vec.h:591:30: runtime error: member access within null pointer of type 'struct vec'

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98626

--- Comment #2 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:11cbea852b0ae2b0f17a9caeaf6344d689231c2f

commit r11-6647-g11cbea852b0ae2b0f17a9caeaf6344d689231c2f
Author: Nathan Sidwell <nathan@acm.org>
Date:   Wed Jan 13 05:13:12 2021 -0800

    c++: Fix cp_build_function_call_vec [PR 98626]

    I misunderstood the cp_build_function_call_vec API, thinking a NULL
    vector was an acceptable way of passing no arguments.  You need to
    pass a vector of no elements.

            PR c++/98626
            gcc/cp/
            * module.cc (module_add_import_initializers):  Pass a
            zero-element argument vector.

[Bug c++/98626] UBSAN: vec.h:591:30: runtime error: member access within null pointer of type 'struct vec'

[nathan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98626

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

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

--- Comment #3 from Nathan Sidwell <nathan at gcc dot gnu.org> ---
Fixed 11cbea852b0 2021-01-13 | c++: Fix cp_build_function_call_vec [PR 98626]