[Bug analyzer/112811] ICE in -fanalyzer in has_null_terminator

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112811

--- Comment #1 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by David Malcolm <dmalcolm@gcc.gnu.org>:

https://gcc.gnu.org/g:84096e665c5f7d7ffb07f18a5fd5e804a94b237b

commit r14-8256-g84096e665c5f7d7ffb07f18a5fd5e804a94b237b
Author: David Malcolm <dmalcolm@redhat.com>
Date:   Thu Jan 18 12:11:57 2024 -0500

    analyzer: fix offsets in has_null_terminator [PR112811]

    PR analyzer/112811 reports an ICE attempting to determine whether a
    string is null-terminated.

    The root cause is confusion in the code about whether byte offsets are
    relative to the start of the base region, or relative to the bound
    fragment within the the region.

    This patch rewrites the code to enforce a clearer separation between
    the kinds of offset, fixing the ICE, and adds logging to help track
    down future issues in this area of the code.

    gcc/analyzer/ChangeLog:
            PR analyzer/112811
            * region-model.cc (fragment::dump_to_pp): New.
            (fragment::has_null_terminator): Convert to...
            (svalue_byte_range_has_null_terminator_1): ...this new function,
            updating to use a byte_range relative to the start of the svalue.
            (svalue_byte_range_has_null_terminator): New.
            (fragment::string_cst_has_null_terminator): Convert to...
            (string_cst_has_null_terminator): ...this, updating to use a
            byte_range relative to the start of the svalue.
            (iterable_cluster::dump_to_pp): New.
            (region_model::scan_for_null_terminator): Add logging, moving body
            to...
            (region_model::scan_for_null_terminator_1): ...this new function,
            adding more logging, and updating to use
            svalue_byte_range_has_null_terminator.
            * region-model.h (region_model::scan_for_null_terminator_1): New
            decl.

    gcc/testsuite/ChangeLog:
            PR analyzer/112811
            * c-c++-common/analyzer/strlen-pr112811.c: New test.

    Signed-off-by: David Malcolm <dmalcolm@redhat.com>