[Bug preprocessor/105608] [11/12/13/14 Regression] ICE: in linemap_add with a really long defined macro on the command line r11-338-g2a0225e47868fbfc

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105608

--- Comment #15 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Lewis Hyatt <lhyatt@gcc.gnu.org>:

https://gcc.gnu.org/g:019dc63819befb2b82077fb2d76b5dd670946f36

commit r14-8698-g019dc63819befb2b82077fb2d76b5dd670946f36
Author: Lewis Hyatt <lhyatt@gmail.com>
Date:   Wed Jan 31 15:50:11 2024 -0500

    libcpp: Stabilize the location for macros restored after PCH load
[PR105608]

    libcpp currently lacks the infrastructure to assign correct locations to
    macros that were defined prior to loading a PCH and then restored
    afterwards. While I plan to address that fully for GCC 15, this patch
    improves things by using at least a valid location, even if it's not the
    best one. Without this change, libcpp uses pfile->directive_line as the
    location for the restored macros, but this location_t applies to the old
    line map, not the one that was just restored from the PCH, so the resulting
    location is unpredictable and depends on what was stored in the line maps
    before. With this change, all restored macros get assigned locations at the
    line of the #include that triggered the PCH restore. A future patch will
    store the actual file name and line number of each definition and then
    synthesize locations in the new line map pointing to the right place.

    gcc/c-family/ChangeLog:

            PR preprocessor/105608
            * c-pch.cc (c_common_read_pch): Adjust line map so that libcpp
            assigns a location to restored macros which is the same location
            that triggered the PCH include.

    libcpp/ChangeLog:

            PR preprocessor/105608
            * pch.cc (cpp_read_state): Set a valid location for restored
            macros.