[Bug c++/106820] internal compiler error: in function_and_variable_visibility [for std::shared_ptr<data>{b,??} use via <memory> module]

["markmigm at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106820

--- Comment #3 from Mark Millard <markmigm at gmail dot com> ---
(In reply to Mark Millard from comment #2)

I managed to build lang/gcc12 with -g -O0 in use and so
can report:

The failing assert looks like:

      gcc_assert ((!DECL_WEAK (node->decl)
                  && !DECL_COMDAT (node->decl))
                  || TREE_PUBLIC (node->decl)
                  || node->weakref

                  || DECL_EXTERNAL (node->decl));

And in a debugger I see:

(lldb) print node->decl->decl_with_vis.weak_flag
(unsigned int) $2 = 1
(lldb) print node->decl->decl_with_vis.comdat_flag
(unsigned int) $3 = 0
(lldb) print node->weakref
(unsigned int) $4 = 0
(lldb) print node->decl->decl_common.decl_flag_1
(unsigned int) $5 = 0

and:

(lldb) call debug_tree(node->decl)
 <function_decl 0x9986ca00 __gthrw_pthread_mutex_unlock
    type <function_type 0x939e7e70
        type <integer_type 0x8cd415e8 int sizes-gimplified public type_6 SI
            size <integer_cst 0x8cd40258 constant 32>
            unit-size <integer_cst 0x8cd40270 constant 4>
            align:32 warn_if_not_align:0 symtab:0 alias-set -1 canonical-type
0x8cd415e8 precision:32 min <integer_cst 0x8cd40210 -2147483648> max
<integer_cst 0x8cd40228 2147483647>
            pointer_to_this <pointer_type 0x8cd48a80> reference_to_this
<reference_type 0x9bb63000>>
        SI size <integer_cst 0x8cd40258 32> unit-size <integer_cst 0x8cd40270
4>
        align:32 warn_if_not_align:0 symtab:0 alias-set -1 canonical-type
0x939e7f18
        arg-types <tree_list 0x9986d168 value <pointer_type 0x939e7a80>
            chain <tree_list 0x8cd2b938 value <void_type 0x8cd41f18 void>>>
        pointer_to_this <pointer_type 0x99870150>>
    addressable used static tree_3 weak in_system_header decl_5 decl_6 DI
/usr/local/lib/gcc12/include/c++/aarch64-portbld-freebsd14.0/bits/gthr-default.h:121:1
align:32 warn_if_not_align:0 context <translation_unit_decl 0x8cd3e000
module_shared_ptr_alias_construction_failure.cpp>
    attributes <tree_list 0x9986d230
        purpose <identifier_node 0x939ca980 alias
            normal local bindings <0x0>>
        value <tree_list 0x9986d258
            value <string_cst 0x939c6d80 type <array_type 0x939e77e0>
                readonly constant static "pthread_mutex_unlock\000">>
        chain <tree_list 0x9986d280
            purpose <identifier_node 0x939ca9c0 weakref
                normal local bindings <0x0>>>>
    full-name "int __gthrw_pthread_mutex_unlock(pthread_mutex**)"
    module 1:/usr/local/lib/gcc12/include/c++/memory exported chain
<function_decl 0x9986c900 __gthread_trigger>>