[Bug preprocessor/60723] Line directives with incorrect system header flag

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60723

--- Comment #32 from CVS 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:ddb7f0a0cac48762ba6408d69538f8115c4a2739

commit r13-3264-gddb7f0a0cac48762ba6408d69538f8115c4a2739
Author: Lewis Hyatt <lhyatt@gmail.com>
Date:   Thu Oct 6 18:05:02 2022 -0400

    preprocessor: Fix tracking of system header state [PR60014,PR60723]

    The token_streamer class (which implements gcc mode -E and
    -save-temps/-no-integrated-cpp) needs to keep track whether the last tokens
    output were in a system header, so that it can generate line marker
    annotations as necessary for a downstream consumer to reconstruct the
    state. The logic for tracking it, which was added by r5-1863 to resolve
    PR60723, has some edge case issues as revealed by the three new test
    cases. The first, coming from the original PR60014, was incidentally fixed
by
    r9-1926 for unrelated reasons. The other two were still failing on master
    prior to this commit. Such code paths were not realizable prior to
r13-1544,
    which made it possible for the token streamer to see CPP_PRAGMA tokens in
more
    contexts.

    The two main issues being corrected here are:

    1) print.prev_was_system_token needs to indicate whether the previous token
    output was in a system location. However, it was not being set on every
token,
    only on those that triggered the main code path; specifically it was not
    triggered on a CPP_PRAGMA token. Testcase 2 covers this case.

    2) The token_streamer uses a variable "line_marker_emitted" to remember
    whether a line marker has been emitted while processing a given token, so
that
    it wouldn't be done more than once in case multiple conditions requiring a
    line marker are true. There was no reason for this to be a member variable
    that retains its value from token to token, since it is just needed for
    tracking the state locally while processing a single given token. The fact
    that it could retain its value for a subsequent token is rather difficult
to
    observe, but testcase 3 demonstrates incorrect behavior resulting from
    that. Moving this to a local variable also simplifies understanding the
    control flow going forward.

    gcc/c-family/ChangeLog:

            PR preprocessor/60014
            PR preprocessor/60723
            * c-ppoutput.cc (class token_streamer): Remove member
            line_marker_emitted to...
            (token_streamer::stream): ...a local variable here. Set
            print.prev_was_system_token on all code paths.

    gcc/testsuite/ChangeLog:

            PR preprocessor/60014
            PR preprocessor/60723
            * gcc.dg/cpp/pr60014-1.c: New test.
            * gcc.dg/cpp/pr60014-1.h: New test.
            * gcc.dg/cpp/pr60014-2.c: New test.
            * gcc.dg/cpp/pr60014-2.h: New test.
            * gcc.dg/cpp/pr60014-3.c: New test.
            * gcc.dg/cpp/pr60014-3.h: New test.