[Bug lto/94237] [10 regression] Many (100s) of new LTO fails on Darwin targets

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94237

--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Iain D Sandoe <iains@gcc.gnu.org>:

https://gcc.gnu.org/g:dfb25dfe3d34703f6e493664831dfaf53672b07b

commit r10-7316-gdfb25dfe3d34703f6e493664831dfaf53672b07b
Author: Iain Sandoe <iain@sandoe.co.uk>
Date:   Sat Mar 21 13:20:47 2020 +0000

    Darwin: Handle NULL DECL_SIZE_TYPE in machopic_select_section (PR94237).

    A recent change in the LTO streaming arrangement means that it is
    now possible for machopic_select_section () to be called with a NULL
    value for DECL_SIZE_TYPE - corresponding to an incomplete or not-yet-
    laid out type.

    When section anchors are present, and we are generating assembler, we
    normally need to know the object size when choosing the section, since
    zero-sized objects must be placed in sections that forbid section
    anchors.

    In the current circumstance, the objective of the earlier streaming of
    this data is to allow nm to determine BSS c.f. Data symbols (when used
    with the LTO plugin).  Since Darwin does not yet make use of the plugin
    this fix is a bit of future-proofing.  We now emit the 'generic' section
    for the decl (absent knowing its size) - which will still be correct in
    determining the BSS c.f. Data case.

    gcc/ChangeLog:

    2020-03-21  Iain Sandoe  <iain@sandoe.co.uk>

            PR lto/94237
            * config/darwin.c (darwin_mergeable_constant_section): Collect
            section anchor checks into the caller.
            (machopic_select_section): Collect section anchor checks into
            the determination of 'effective zero-size' objects.  When the
            size is unknown, assume it is non-zero, and thus return the
            'generic' section for the DECL.