[Bug middle-end/109128] [Offload][OpenMP][OpenACC] Static linking with unused offload function will lead to mismatch number of offload fn/symbols

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109128

--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Tobias Burnus <burnus@gcc.gnu.org>:

https://gcc.gnu.org/g:c49d51fa8134f6c7e6c7cf6e4e3007c4fea617c5

commit r14-677-gc49d51fa8134f6c7e6c7cf6e4e3007c4fea617c5
Author: Joseph Myers <joseph@codesourcery.com>
Date:   Thu May 11 10:07:00 2023 +0200

    Implement LDPT_REGISTER_CLAIM_FILE_HOOK_V2 linker plugin hook [PR109128]

    This is one part of the fix for PR109128, along with a corresponding
    binutils's linker change.  Without this patch, what happens in the
    linker, when an unused object in a .a file has offload data, is that
    elf_link_is_defined_archive_symbol calls bfd_link_plugin_object_p,
    which ends up calling the plugin's claim_file_handler, which then
    records the object as one with offload data. That is, the linker never
    decides to use the object in the first place, but use of this _p
    interface (called as part of trying to decide whether to use the
    object) results in the plugin deciding to use its offload data (and a
    consequent mismatch in the offload data present at runtime).

    The new hook allows the linker plugin to distinguish calls to
    claim_file_handler that know the object is being used by the linker
    (from ldmain.c:add_archive_element), from calls that don't know it's
    being used by the linker (from elf_link_is_defined_archive_symbol); in
    the latter case, the plugin should avoid recording the object as one
    with offload data.

            PR middle-end/109128

            include/
            * plugin-api.h (ld_plugin_claim_file_handler_v2)
            (ld_plugin_register_claim_file_v2)
            (LDPT_REGISTER_CLAIM_FILE_HOOK_V2): New.
            (struct ld_plugin_tv): Add tv_register_claim_file_v2.

            lto-plugin/
            * lto-plugin.c (register_claim_file_v2): New.
            (claim_file_handler_v2): New.
            (claim_file_handler): Wrap claim_file_handler_v2.
            (onload): Handle LDPT_REGISTER_CLAIM_FILE_HOOK_V2.