[Bug analyzer/108524] -Wanalyzer-infinite-recursion false positives seen in qemu's JSON parser

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108524

--- Comment #2 from CVS 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:7bffea89f1f164efc10dd37d979a83c4c5fbfa7e

commit r13-5388-g7bffea89f1f164efc10dd37d979a83c4c5fbfa7e
Author: David Malcolm <dmalcolm@redhat.com>
Date:   Thu Jan 26 09:12:21 2023 -0500

    analyzer: fix false positives from -Wanalyzer-infinite-recursion [PR108524]

    Reject -Wanalyzer-infinite-recursion diagnostics in which control flow
    has been affected by conjured_svalues between the initial call to a
    function and the subsequent entry to that function.  This prevents false
    positives such as in qemu's recursive JSON parser where function calls are
    changing state in the rest of the program (e.g. consuming tokens), despite
    the modelled state being effectively identical at both nested entrypoints.

    gcc/analyzer/ChangeLog:
            PR analyzer/108524
            * analyzer.h (class feasible_node): New forward decl.
            * diagnostic-manager.cc (epath_finder::get_best_epath): Add "pd"
            param.
            (epath_finder::explore_feasible_paths): Likewise.
            (epath_finder::process_worklist_item): Likewise.  Use it to call
            pending_diagnostic::check_valid_fpath_p on the final fpath to
            give pending_diagnostic a way to add additional restrictions on
            feasibility.
            (saved_diagnostic::calc_best_epath): Pass pending_diagnostic to
            epath_finder::get_best_epath.
            * infinite-recursion.cc: Include "analyzer/feasible-graph.h".
            (infinite_recursion_diagnostic::check_valid_fpath_p): New.
            (infinite_recursion_diagnostic::fedge_uses_conjured_svalue_p): New.
            (infinite_recursion_diagnostic::expr_uses_conjured_svalue_p): New.
            * pending-diagnostic.h (pending_diagnostic::check_valid_fpath_p):
            New vfunc.

    gcc/testsuite/ChangeLog:
            PR analyzer/108524
            * gcc.dg/analyzer/infinite-recursion-pr108524-1.c: New test.
            * gcc.dg/analyzer/infinite-recursion-pr108524-2.c: New test.
            *
gcc.dg/analyzer/infinite-recursion-pr108524-qobject-json-parser.c:
            New test.

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