[Bug analyzer/97114] Support for vfuncs in -fanalyzer

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97114

--- Comment #4 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Egas Ribeiro <egas@gcc.gnu.org>:

https://gcc.gnu.org/g:8f1698229d33a74cda7ec9f02575172df10b2774

commit r17-2756-g8f1698229d33a74cda7ec9f02575172df10b2774
Author: Egas Ribeiro <egas.g.ribeiro@gmail.com>
Date:   Sun Jul 5 11:59:51 2026 +0100

    analyzer: support vfunc devirtualization [PR97114]

    The analyzer doesn't currently support virtual function call resolution,
    and has no way to devirtualize concrete calls.

    This patch adds support for devirtualization of virtual methods by
    adding logic around OBJ_TYPE_REF calls and using the information it
    tracks to link the calls back to the concrete subclass implementation
    stored in the OBJ_TYPE_REF_OBJECT's vptr field.

    This approach relies on the pre-existing store binding mechanism to keep
    track of which _ZTV* instance the object's vptr field points to, and
    thus doesn't require any additional modeling of the dynamic type of the
    object to resolve calls.

    can_throw_p is also extended to consider thunks that wrap virtual
    methods when dealing with multiple inheritance, and now checks
    TREE_NOTHROW for more accurate results (i.e considers noexcept
    attributes on methods).

            PR analyzer/97114

    gcc/analyzer/ChangeLog:

            * region-model.cc (can_throw_p): improve NOTHROW detection and
            consider the thunk case.
            (region_model::get_fndecl_for_virtual_call): New function.
            (region_model::get_fndecl_for_call): Update to use
            get_fndecl_for_virtual_call on OBJ_TYPE_REF.
            * region-model.h (class region_model): New decl.

    gcc/testsuite/ChangeLog:

            * g++.dg/analyzer/devirt-1.C: New test.
            * g++.dg/analyzer/devirt-multiple-inheritance-1.C: New test.
            * g++.dg/analyzer/devirt-noexcept-1.C: New test.
            * g++.dg/analyzer/devirt-unknown-1.C: New test.

    Signed-off-by: Egas Ribeiro <egas.g.ribeiro@gmail.com>